From 0588fa30db44fd2d4032b36a061c87478a43fbee Mon Sep 17 00:00:00 2001 From: Steven Rostedt Date: Mon, 21 Mar 2011 22:59:21 -0400 Subject: tracing: Convert trace_printk() formats for module to const char * The trace_printk() formats for modules do not show up in the debugfs/tracing/printk_formats file. Only the formats that are for trace_printk()s that are in the kernel core. To facilitate the change to add trace_printk() formats from modules into that file as well, we need to convert the structure that holds the formats from char fmt[], into const char *fmt, and allocate them separately. Signed-off-by: Steven Rostedt --- kernel/trace/trace_printk.c | 17 +++++++++++------ 1 file changed, 11 insertions(+), 6 deletions(-) (limited to 'kernel') diff --git a/kernel/trace/trace_printk.c b/kernel/trace/trace_printk.c index 2547d88..b8b2681 100644 --- a/kernel/trace/trace_printk.c +++ b/kernel/trace/trace_printk.c @@ -32,7 +32,7 @@ static DEFINE_MUTEX(btrace_mutex); struct trace_bprintk_fmt { struct list_head list; - char fmt[0]; + const char *fmt; }; static inline struct trace_bprintk_fmt *lookup_format(const char *fmt) @@ -49,6 +49,7 @@ static void hold_module_trace_bprintk_format(const char **start, const char **end) { const char **iter; + char *fmt; mutex_lock(&btrace_mutex); for (iter = start; iter < end; iter++) { @@ -58,14 +59,18 @@ void hold_module_trace_bprintk_format(const char **start, const char **end) continue; } - tb_fmt = kmalloc(offsetof(struct trace_bprintk_fmt, fmt) - + strlen(*iter) + 1, GFP_KERNEL); - if (tb_fmt) { + tb_fmt = kmalloc(sizeof(*tb_fmt), GFP_KERNEL); + if (tb_fmt) + fmt = kmalloc(strlen(*iter) + 1, GFP_KERNEL); + if (tb_fmt && fmt) { list_add_tail(&tb_fmt->list, &trace_bprintk_fmt_list); - strcpy(tb_fmt->fmt, *iter); + strcpy(fmt, *iter); + tb_fmt->fmt = fmt; *iter = tb_fmt->fmt; - } else + } else { + kfree(tb_fmt); *iter = NULL; + } } mutex_unlock(&btrace_mutex); } -- cgit v1.1 From 1813dc3776c22ad4b0294a6df8434b9a02c98109 Mon Sep 17 00:00:00 2001 From: Steven Rostedt Date: Mon, 21 Mar 2011 23:36:31 -0400 Subject: tracing: Print trace_bprintk() formats for modules too The file debugfs/tracing/printk_formats maps the addresses to the formats that are used by trace_bprintk() so that userspace tools can read the buffer and be able to decode trace_bprintk events to get the format saved when reading the ring buffer directly. This is because trace_bprintk() does not store the format into the buffer, but just the address of the format, which is hidden in the kernel memory. But currently it only exports trace_bprintk()s from the kernel core and not for modules. The modules need their formats exported as well. Signed-off-by: Steven Rostedt --- kernel/trace/trace_printk.c | 103 +++++++++++++++++++++++++++++++++++++++++--- 1 file changed, 97 insertions(+), 6 deletions(-) (limited to 'kernel') diff --git a/kernel/trace/trace_printk.c b/kernel/trace/trace_printk.c index b8b2681..dff763b 100644 --- a/kernel/trace/trace_printk.c +++ b/kernel/trace/trace_printk.c @@ -89,6 +89,76 @@ static int module_trace_bprintk_format_notify(struct notifier_block *self, return 0; } +/* + * The debugfs/tracing/printk_formats file maps the addresses with + * the ASCII formats that are used in the bprintk events in the + * buffer. For userspace tools to be able to decode the events from + * the buffer, they need to be able to map the address with the format. + * + * The addresses of the bprintk formats are in their own section + * __trace_printk_fmt. But for modules we copy them into a link list. + * The code to print the formats and their addresses passes around the + * address of the fmt string. If the fmt address passed into the seq + * functions is within the kernel core __trace_printk_fmt section, then + * it simply uses the next pointer in the list. + * + * When the fmt pointer is outside the kernel core __trace_printk_fmt + * section, then we need to read the link list pointers. The trick is + * we pass the address of the string to the seq function just like + * we do for the kernel core formats. To get back the structure that + * holds the format, we simply use containerof() and then go to the + * next format in the list. + */ +static const char ** +find_next_mod_format(int start_index, void *v, const char **fmt, loff_t *pos) +{ + struct trace_bprintk_fmt *mod_fmt; + + if (list_empty(&trace_bprintk_fmt_list)) + return NULL; + + /* + * v will point to the address of the fmt record from t_next + * v will be NULL from t_start. + * If this is the first pointer or called from start + * then we need to walk the list. + */ + if (!v || start_index == *pos) { + struct trace_bprintk_fmt *p; + + /* search the module list */ + list_for_each_entry(p, &trace_bprintk_fmt_list, list) { + if (start_index == *pos) + return &p->fmt; + start_index++; + } + /* pos > index */ + return NULL; + } + + /* + * v points to the address of the fmt field in the mod list + * structure that holds the module print format. + */ + mod_fmt = container_of(v, typeof(*mod_fmt), fmt); + if (mod_fmt->list.next == &trace_bprintk_fmt_list) + return NULL; + + mod_fmt = container_of(mod_fmt->list.next, typeof(*mod_fmt), list); + + return &mod_fmt->fmt; +} + +static void format_mod_start(void) +{ + mutex_lock(&btrace_mutex); +} + +static void format_mod_stop(void) +{ + mutex_unlock(&btrace_mutex); +} + #else /* !CONFIG_MODULES */ __init static int module_trace_bprintk_format_notify(struct notifier_block *self, @@ -96,6 +166,13 @@ module_trace_bprintk_format_notify(struct notifier_block *self, { return 0; } +static inline const char ** +find_next_mod_format(int start_index, void *v, const char **fmt, loff_t *pos) +{ + return NULL; +} +static inline void format_mod_start(void) { } +static inline void format_mod_stop(void) { } #endif /* CONFIG_MODULES */ @@ -158,20 +235,33 @@ int __ftrace_vprintk(unsigned long ip, const char *fmt, va_list ap) } EXPORT_SYMBOL_GPL(__ftrace_vprintk); +static const char **find_next(void *v, loff_t *pos) +{ + const char **fmt = v; + int start_index; + + if (!fmt) + fmt = __start___trace_bprintk_fmt + *pos; + + start_index = __stop___trace_bprintk_fmt - __start___trace_bprintk_fmt; + + if (*pos < start_index) + return fmt; + + return find_next_mod_format(start_index, v, fmt, pos); +} + static void * t_start(struct seq_file *m, loff_t *pos) { - const char **fmt = __start___trace_bprintk_fmt + *pos; - - if ((unsigned long)fmt >= (unsigned long)__stop___trace_bprintk_fmt) - return NULL; - return fmt; + format_mod_start(); + return find_next(NULL, pos); } static void *t_next(struct seq_file *m, void * v, loff_t *pos) { (*pos)++; - return t_start(m, pos); + return find_next(v, pos); } static int t_show(struct seq_file *m, void *v) @@ -210,6 +300,7 @@ static int t_show(struct seq_file *m, void *v) static void t_stop(struct seq_file *m, void *p) { + format_mod_stop(); } static const struct seq_operations show_format_seq_ops = { -- cgit v1.1 From ee5e51f51be755830f57445e268ba50e88ccbdbb Mon Sep 17 00:00:00 2001 From: Jiri Olsa Date: Fri, 25 Mar 2011 12:05:18 +0100 Subject: tracing: Avoid soft lockup in trace_pipe running following commands: # enable the binary option echo 1 > ./options/bin # disable context info option echo 0 > ./options/context-info # tracing only events echo 1 > ./events/enable cat trace_pipe plus forcing system to generate many tracing events, is causing lockup (in NON preemptive kernels) inside tracing_read_pipe function. The issue is also easily reproduced by running ltp stress test. (ftrace_stress_test.sh) The reasons are: - bin/hex/raw output functions for events are set to trace_nop_print function, which prints nothing and returns TRACE_TYPE_HANDLED value - LOST EVENT trace do not handle trace_seq overflow These reasons force the while loop in tracing_read_pipe function never to break. The attached patch fixies handling of lost event trace, and changes trace_nop_print to print minimal info, which is needed for the correct tracing_read_pipe processing. v2 changes: - omit the cond_resched changes by trace_nop_print changes - WARN changed to WARN_ONCE and added info to be able to find out the culprit v3 changes: - make more accurate patch comment Signed-off-by: Jiri Olsa LKML-Reference: <20110325110518.GC1922@jolsa.brq.redhat.com> Signed-off-by: Steven Rostedt --- kernel/trace/trace.c | 15 ++++++++++++--- kernel/trace/trace_output.c | 3 +++ 2 files changed, 15 insertions(+), 3 deletions(-) (limited to 'kernel') diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c index 9541c27..5af42f4 100644 --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -2013,9 +2013,10 @@ enum print_line_t print_trace_line(struct trace_iterator *iter) { enum print_line_t ret; - if (iter->lost_events) - trace_seq_printf(&iter->seq, "CPU:%d [LOST %lu EVENTS]\n", - iter->cpu, iter->lost_events); + if (iter->lost_events && + !trace_seq_printf(&iter->seq, "CPU:%d [LOST %lu EVENTS]\n", + iter->cpu, iter->lost_events)) + return TRACE_TYPE_PARTIAL_LINE; if (iter->trace && iter->trace->print_line) { ret = iter->trace->print_line(iter); @@ -3229,6 +3230,14 @@ waitagain: if (iter->seq.len >= cnt) break; + + /* + * Setting the full flag means we reached the trace_seq buffer + * size and we should leave by partial output condition above. + * One of the trace_seq_* functions is not used properly. + */ + WARN_ONCE(iter->seq.full, "full flag set for trace type %d", + iter->ent->type); } trace_access_unlock(iter->cpu_file); trace_event_read_unlock(); diff --git a/kernel/trace/trace_output.c b/kernel/trace/trace_output.c index 456be90..cf535cc 100644 --- a/kernel/trace/trace_output.c +++ b/kernel/trace/trace_output.c @@ -830,6 +830,9 @@ EXPORT_SYMBOL_GPL(unregister_ftrace_event); enum print_line_t trace_nop_print(struct trace_iterator *iter, int flags, struct trace_event *event) { + if (!trace_seq_printf(&iter->seq, "type: %d\n", iter->ent->type)) + return TRACE_TYPE_PARTIAL_LINE; + return TRACE_TYPE_HANDLED; } -- cgit v1.1 From d430d3d7e646eb1eac2bb4aa244a644312e67c76 Mon Sep 17 00:00:00 2001 From: Jason Baron Date: Wed, 16 Mar 2011 17:29:47 -0400 Subject: jump label: Introduce static_branch() interface Introduce: static __always_inline bool static_branch(struct jump_label_key *key); instead of the old JUMP_LABEL(key, label) macro. In this way, jump labels become really easy to use: Define: struct jump_label_key jump_key; Can be used as: if (static_branch(&jump_key)) do unlikely code enable/disale via: jump_label_inc(&jump_key); jump_label_dec(&jump_key); that's it! For the jump labels disabled case, the static_branch() becomes an atomic_read(), and jump_label_inc()/dec() are simply atomic_inc(), atomic_dec() operations. We show testing results for this change below. Thanks to H. Peter Anvin for suggesting the 'static_branch()' construct. Since we now require a 'struct jump_label_key *key', we can store a pointer into the jump table addresses. In this way, we can enable/disable jump labels, in basically constant time. This change allows us to completely remove the previous hashtable scheme. Thanks to Peter Zijlstra for this re-write. Testing: I ran a series of 'tbench 20' runs 5 times (with reboots) for 3 configurations, where tracepoints were disabled. jump label configured in avg: 815.6 jump label *not* configured in (using atomic reads) avg: 800.1 jump label *not* configured in (regular reads) avg: 803.4 Signed-off-by: Peter Zijlstra LKML-Reference: <20110316212947.GA8792@redhat.com> Signed-off-by: Jason Baron Suggested-by: H. Peter Anvin Tested-by: David Daney Acked-by: Ralf Baechle Acked-by: David S. Miller Acked-by: Mathieu Desnoyers Signed-off-by: Steven Rostedt --- kernel/jump_label.c | 539 +++++++++++++++++++++------------------------------- kernel/perf_event.c | 4 +- kernel/tracepoint.c | 23 +-- 3 files changed, 229 insertions(+), 337 deletions(-) (limited to 'kernel') diff --git a/kernel/jump_label.c b/kernel/jump_label.c index 3b79bd9..74d1c09 100644 --- a/kernel/jump_label.c +++ b/kernel/jump_label.c @@ -2,43 +2,23 @@ * jump label support * * Copyright (C) 2009 Jason Baron + * Copyright (C) 2011 Peter Zijlstra * */ -#include #include #include #include #include -#include #include #include #include +#include #ifdef HAVE_JUMP_LABEL -#define JUMP_LABEL_HASH_BITS 6 -#define JUMP_LABEL_TABLE_SIZE (1 << JUMP_LABEL_HASH_BITS) -static struct hlist_head jump_label_table[JUMP_LABEL_TABLE_SIZE]; - /* mutex to protect coming/going of the the jump_label table */ static DEFINE_MUTEX(jump_label_mutex); -struct jump_label_entry { - struct hlist_node hlist; - struct jump_entry *table; - int nr_entries; - /* hang modules off here */ - struct hlist_head modules; - unsigned long key; -}; - -struct jump_label_module_entry { - struct hlist_node hlist; - struct jump_entry *table; - int nr_entries; - struct module *mod; -}; - void jump_label_lock(void) { mutex_lock(&jump_label_mutex); @@ -49,6 +29,11 @@ void jump_label_unlock(void) mutex_unlock(&jump_label_mutex); } +bool jump_label_enabled(struct jump_label_key *key) +{ + return !!atomic_read(&key->enabled); +} + static int jump_label_cmp(const void *a, const void *b) { const struct jump_entry *jea = a; @@ -64,7 +49,7 @@ static int jump_label_cmp(const void *a, const void *b) } static void -sort_jump_label_entries(struct jump_entry *start, struct jump_entry *stop) +jump_label_sort_entries(struct jump_entry *start, struct jump_entry *stop) { unsigned long size; @@ -73,118 +58,25 @@ sort_jump_label_entries(struct jump_entry *start, struct jump_entry *stop) sort(start, size, sizeof(struct jump_entry), jump_label_cmp, NULL); } -static struct jump_label_entry *get_jump_label_entry(jump_label_t key) -{ - struct hlist_head *head; - struct hlist_node *node; - struct jump_label_entry *e; - u32 hash = jhash((void *)&key, sizeof(jump_label_t), 0); - - head = &jump_label_table[hash & (JUMP_LABEL_TABLE_SIZE - 1)]; - hlist_for_each_entry(e, node, head, hlist) { - if (key == e->key) - return e; - } - return NULL; -} +static void jump_label_update(struct jump_label_key *key, int enable); -static struct jump_label_entry * -add_jump_label_entry(jump_label_t key, int nr_entries, struct jump_entry *table) +void jump_label_inc(struct jump_label_key *key) { - struct hlist_head *head; - struct jump_label_entry *e; - u32 hash; - - e = get_jump_label_entry(key); - if (e) - return ERR_PTR(-EEXIST); - - e = kmalloc(sizeof(struct jump_label_entry), GFP_KERNEL); - if (!e) - return ERR_PTR(-ENOMEM); - - hash = jhash((void *)&key, sizeof(jump_label_t), 0); - head = &jump_label_table[hash & (JUMP_LABEL_TABLE_SIZE - 1)]; - e->key = key; - e->table = table; - e->nr_entries = nr_entries; - INIT_HLIST_HEAD(&(e->modules)); - hlist_add_head(&e->hlist, head); - return e; -} + if (atomic_inc_not_zero(&key->enabled)) + return; -static int -build_jump_label_hashtable(struct jump_entry *start, struct jump_entry *stop) -{ - struct jump_entry *iter, *iter_begin; - struct jump_label_entry *entry; - int count; - - sort_jump_label_entries(start, stop); - iter = start; - while (iter < stop) { - entry = get_jump_label_entry(iter->key); - if (!entry) { - iter_begin = iter; - count = 0; - while ((iter < stop) && - (iter->key == iter_begin->key)) { - iter++; - count++; - } - entry = add_jump_label_entry(iter_begin->key, - count, iter_begin); - if (IS_ERR(entry)) - return PTR_ERR(entry); - } else { - WARN_ONCE(1, KERN_ERR "build_jump_hashtable: unexpected entry!\n"); - return -1; - } - } - return 0; + jump_label_lock(); + if (atomic_add_return(1, &key->enabled) == 1) + jump_label_update(key, JUMP_LABEL_ENABLE); + jump_label_unlock(); } -/*** - * jump_label_update - update jump label text - * @key - key value associated with a a jump label - * @type - enum set to JUMP_LABEL_ENABLE or JUMP_LABEL_DISABLE - * - * Will enable/disable the jump for jump label @key, depending on the - * value of @type. - * - */ - -void jump_label_update(unsigned long key, enum jump_label_type type) +void jump_label_dec(struct jump_label_key *key) { - struct jump_entry *iter; - struct jump_label_entry *entry; - struct hlist_node *module_node; - struct jump_label_module_entry *e_module; - int count; + if (!atomic_dec_and_mutex_lock(&key->enabled, &jump_label_mutex)) + return; - jump_label_lock(); - entry = get_jump_label_entry((jump_label_t)key); - if (entry) { - count = entry->nr_entries; - iter = entry->table; - while (count--) { - if (kernel_text_address(iter->code)) - arch_jump_label_transform(iter, type); - iter++; - } - /* eanble/disable jump labels in modules */ - hlist_for_each_entry(e_module, module_node, &(entry->modules), - hlist) { - count = e_module->nr_entries; - iter = e_module->table; - while (count--) { - if (iter->key && - kernel_text_address(iter->code)) - arch_jump_label_transform(iter, type); - iter++; - } - } - } + jump_label_update(key, JUMP_LABEL_DISABLE); jump_label_unlock(); } @@ -197,77 +89,33 @@ static int addr_conflict(struct jump_entry *entry, void *start, void *end) return 0; } -#ifdef CONFIG_MODULES - -static int module_conflict(void *start, void *end) +static int __jump_label_text_reserved(struct jump_entry *iter_start, + struct jump_entry *iter_stop, void *start, void *end) { - struct hlist_head *head; - struct hlist_node *node, *node_next, *module_node, *module_node_next; - struct jump_label_entry *e; - struct jump_label_module_entry *e_module; struct jump_entry *iter; - int i, count; - int conflict = 0; - - for (i = 0; i < JUMP_LABEL_TABLE_SIZE; i++) { - head = &jump_label_table[i]; - hlist_for_each_entry_safe(e, node, node_next, head, hlist) { - hlist_for_each_entry_safe(e_module, module_node, - module_node_next, - &(e->modules), hlist) { - count = e_module->nr_entries; - iter = e_module->table; - while (count--) { - if (addr_conflict(iter, start, end)) { - conflict = 1; - goto out; - } - iter++; - } - } - } - } -out: - return conflict; -} - -#endif - -/*** - * jump_label_text_reserved - check if addr range is reserved - * @start: start text addr - * @end: end text addr - * - * checks if the text addr located between @start and @end - * overlaps with any of the jump label patch addresses. Code - * that wants to modify kernel text should first verify that - * it does not overlap with any of the jump label addresses. - * Caller must hold jump_label_mutex. - * - * returns 1 if there is an overlap, 0 otherwise - */ -int jump_label_text_reserved(void *start, void *end) -{ - struct jump_entry *iter; - struct jump_entry *iter_start = __start___jump_table; - struct jump_entry *iter_stop = __start___jump_table; - int conflict = 0; iter = iter_start; while (iter < iter_stop) { - if (addr_conflict(iter, start, end)) { - conflict = 1; - goto out; - } + if (addr_conflict(iter, start, end)) + return 1; iter++; } - /* now check modules */ -#ifdef CONFIG_MODULES - conflict = module_conflict(start, end); -#endif -out: - return conflict; + return 0; +} + +static void __jump_label_update(struct jump_label_key *key, + struct jump_entry *entry, int enable) +{ + for (; entry->key == (jump_label_t)(unsigned long)key; entry++) { + /* + * entry->code set to 0 invalidates module init text sections + * kernel_text_address() verifies we are not in core kernel + * init code, see jump_label_invalidate_module_init(). + */ + if (entry->code && kernel_text_address(entry->code)) + arch_jump_label_transform(entry, enable); + } } /* @@ -277,142 +125,173 @@ void __weak arch_jump_label_text_poke_early(jump_label_t addr) { } -static __init int init_jump_label(void) +static __init int jump_label_init(void) { - int ret; struct jump_entry *iter_start = __start___jump_table; struct jump_entry *iter_stop = __stop___jump_table; + struct jump_label_key *key = NULL; struct jump_entry *iter; jump_label_lock(); - ret = build_jump_label_hashtable(__start___jump_table, - __stop___jump_table); - iter = iter_start; - while (iter < iter_stop) { + jump_label_sort_entries(iter_start, iter_stop); + + for (iter = iter_start; iter < iter_stop; iter++) { arch_jump_label_text_poke_early(iter->code); - iter++; + if (iter->key == (jump_label_t)(unsigned long)key) + continue; + + key = (struct jump_label_key *)(unsigned long)iter->key; + atomic_set(&key->enabled, 0); + key->entries = iter; +#ifdef CONFIG_MODULES + key->next = NULL; +#endif } jump_label_unlock(); - return ret; + + return 0; } -early_initcall(init_jump_label); +early_initcall(jump_label_init); #ifdef CONFIG_MODULES -static struct jump_label_module_entry * -add_jump_label_module_entry(struct jump_label_entry *entry, - struct jump_entry *iter_begin, - int count, struct module *mod) +struct jump_label_mod { + struct jump_label_mod *next; + struct jump_entry *entries; + struct module *mod; +}; + +static int __jump_label_mod_text_reserved(void *start, void *end) +{ + struct module *mod; + + mod = __module_text_address((unsigned long)start); + if (!mod) + return 0; + + WARN_ON_ONCE(__module_text_address((unsigned long)end) != mod); + + return __jump_label_text_reserved(mod->jump_entries, + mod->jump_entries + mod->num_jump_entries, + start, end); +} + +static void __jump_label_mod_update(struct jump_label_key *key, int enable) +{ + struct jump_label_mod *mod = key->next; + + while (mod) { + __jump_label_update(key, mod->entries, enable); + mod = mod->next; + } +} + +/*** + * apply_jump_label_nops - patch module jump labels with arch_get_jump_label_nop() + * @mod: module to patch + * + * Allow for run-time selection of the optimal nops. Before the module + * loads patch these with arch_get_jump_label_nop(), which is specified by + * the arch specific jump label code. + */ +void jump_label_apply_nops(struct module *mod) { - struct jump_label_module_entry *e; - - e = kmalloc(sizeof(struct jump_label_module_entry), GFP_KERNEL); - if (!e) - return ERR_PTR(-ENOMEM); - e->mod = mod; - e->nr_entries = count; - e->table = iter_begin; - hlist_add_head(&e->hlist, &entry->modules); - return e; + struct jump_entry *iter_start = mod->jump_entries; + struct jump_entry *iter_stop = iter_start + mod->num_jump_entries; + struct jump_entry *iter; + + /* if the module doesn't have jump label entries, just return */ + if (iter_start == iter_stop) + return; + + for (iter = iter_start; iter < iter_stop; iter++) + arch_jump_label_text_poke_early(iter->code); } -static int add_jump_label_module(struct module *mod) +static int jump_label_add_module(struct module *mod) { - struct jump_entry *iter, *iter_begin; - struct jump_label_entry *entry; - struct jump_label_module_entry *module_entry; - int count; + struct jump_entry *iter_start = mod->jump_entries; + struct jump_entry *iter_stop = iter_start + mod->num_jump_entries; + struct jump_entry *iter; + struct jump_label_key *key = NULL; + struct jump_label_mod *jlm; /* if the module doesn't have jump label entries, just return */ - if (!mod->num_jump_entries) + if (iter_start == iter_stop) return 0; - sort_jump_label_entries(mod->jump_entries, - mod->jump_entries + mod->num_jump_entries); - iter = mod->jump_entries; - while (iter < mod->jump_entries + mod->num_jump_entries) { - entry = get_jump_label_entry(iter->key); - iter_begin = iter; - count = 0; - while ((iter < mod->jump_entries + mod->num_jump_entries) && - (iter->key == iter_begin->key)) { - iter++; - count++; - } - if (!entry) { - entry = add_jump_label_entry(iter_begin->key, 0, NULL); - if (IS_ERR(entry)) - return PTR_ERR(entry); + jump_label_sort_entries(iter_start, iter_stop); + + for (iter = iter_start; iter < iter_stop; iter++) { + if (iter->key == (jump_label_t)(unsigned long)key) + continue; + + key = (struct jump_label_key *)(unsigned long)iter->key; + + if (__module_address(iter->key) == mod) { + atomic_set(&key->enabled, 0); + key->entries = iter; + key->next = NULL; + continue; } - module_entry = add_jump_label_module_entry(entry, iter_begin, - count, mod); - if (IS_ERR(module_entry)) - return PTR_ERR(module_entry); + + jlm = kzalloc(sizeof(struct jump_label_mod), GFP_KERNEL); + if (!jlm) + return -ENOMEM; + + jlm->mod = mod; + jlm->entries = iter; + jlm->next = key->next; + key->next = jlm; + + if (jump_label_enabled(key)) + __jump_label_update(key, iter, JUMP_LABEL_ENABLE); } + return 0; } -static void remove_jump_label_module(struct module *mod) +static void jump_label_del_module(struct module *mod) { - struct hlist_head *head; - struct hlist_node *node, *node_next, *module_node, *module_node_next; - struct jump_label_entry *e; - struct jump_label_module_entry *e_module; - int i; + struct jump_entry *iter_start = mod->jump_entries; + struct jump_entry *iter_stop = iter_start + mod->num_jump_entries; + struct jump_entry *iter; + struct jump_label_key *key = NULL; + struct jump_label_mod *jlm, **prev; - /* if the module doesn't have jump label entries, just return */ - if (!mod->num_jump_entries) - return; + for (iter = iter_start; iter < iter_stop; iter++) { + if (iter->key == (jump_label_t)(unsigned long)key) + continue; + + key = (struct jump_label_key *)(unsigned long)iter->key; + + if (__module_address(iter->key) == mod) + continue; + + prev = &key->next; + jlm = key->next; - for (i = 0; i < JUMP_LABEL_TABLE_SIZE; i++) { - head = &jump_label_table[i]; - hlist_for_each_entry_safe(e, node, node_next, head, hlist) { - hlist_for_each_entry_safe(e_module, module_node, - module_node_next, - &(e->modules), hlist) { - if (e_module->mod == mod) { - hlist_del(&e_module->hlist); - kfree(e_module); - } - } - if (hlist_empty(&e->modules) && (e->nr_entries == 0)) { - hlist_del(&e->hlist); - kfree(e); - } + while (jlm && jlm->mod != mod) { + prev = &jlm->next; + jlm = jlm->next; + } + + if (jlm) { + *prev = jlm->next; + kfree(jlm); } } } -static void remove_jump_label_module_init(struct module *mod) +static void jump_label_invalidate_module_init(struct module *mod) { - struct hlist_head *head; - struct hlist_node *node, *node_next, *module_node, *module_node_next; - struct jump_label_entry *e; - struct jump_label_module_entry *e_module; + struct jump_entry *iter_start = mod->jump_entries; + struct jump_entry *iter_stop = iter_start + mod->num_jump_entries; struct jump_entry *iter; - int i, count; - - /* if the module doesn't have jump label entries, just return */ - if (!mod->num_jump_entries) - return; - for (i = 0; i < JUMP_LABEL_TABLE_SIZE; i++) { - head = &jump_label_table[i]; - hlist_for_each_entry_safe(e, node, node_next, head, hlist) { - hlist_for_each_entry_safe(e_module, module_node, - module_node_next, - &(e->modules), hlist) { - if (e_module->mod != mod) - continue; - count = e_module->nr_entries; - iter = e_module->table; - while (count--) { - if (within_module_init(iter->code, mod)) - iter->key = 0; - iter++; - } - } - } + for (iter = iter_start; iter < iter_stop; iter++) { + if (within_module_init(iter->code, mod)) + iter->code = 0; } } @@ -426,59 +305,77 @@ jump_label_module_notify(struct notifier_block *self, unsigned long val, switch (val) { case MODULE_STATE_COMING: jump_label_lock(); - ret = add_jump_label_module(mod); + ret = jump_label_add_module(mod); if (ret) - remove_jump_label_module(mod); + jump_label_del_module(mod); jump_label_unlock(); break; case MODULE_STATE_GOING: jump_label_lock(); - remove_jump_label_module(mod); + jump_label_del_module(mod); jump_label_unlock(); break; case MODULE_STATE_LIVE: jump_label_lock(); - remove_jump_label_module_init(mod); + jump_label_invalidate_module_init(mod); jump_label_unlock(); break; } - return ret; -} -/*** - * apply_jump_label_nops - patch module jump labels with arch_get_jump_label_nop() - * @mod: module to patch - * - * Allow for run-time selection of the optimal nops. Before the module - * loads patch these with arch_get_jump_label_nop(), which is specified by - * the arch specific jump label code. - */ -void jump_label_apply_nops(struct module *mod) -{ - struct jump_entry *iter; - - /* if the module doesn't have jump label entries, just return */ - if (!mod->num_jump_entries) - return; - - iter = mod->jump_entries; - while (iter < mod->jump_entries + mod->num_jump_entries) { - arch_jump_label_text_poke_early(iter->code); - iter++; - } + return notifier_from_errno(ret); } struct notifier_block jump_label_module_nb = { .notifier_call = jump_label_module_notify, - .priority = 0, + .priority = 1, /* higher than tracepoints */ }; -static __init int init_jump_label_module(void) +static __init int jump_label_init_module(void) { return register_module_notifier(&jump_label_module_nb); } -early_initcall(init_jump_label_module); +early_initcall(jump_label_init_module); #endif /* CONFIG_MODULES */ +/*** + * jump_label_text_reserved - check if addr range is reserved + * @start: start text addr + * @end: end text addr + * + * checks if the text addr located between @start and @end + * overlaps with any of the jump label patch addresses. Code + * that wants to modify kernel text should first verify that + * it does not overlap with any of the jump label addresses. + * Caller must hold jump_label_mutex. + * + * returns 1 if there is an overlap, 0 otherwise + */ +int jump_label_text_reserved(void *start, void *end) +{ + int ret = __jump_label_text_reserved(__start___jump_table, + __stop___jump_table, start, end); + + if (ret) + return ret; + +#ifdef CONFIG_MODULES + ret = __jump_label_mod_text_reserved(start, end); +#endif + return ret; +} + +static void jump_label_update(struct jump_label_key *key, int enable) +{ + struct jump_entry *entry = key->entries; + + /* if there are no users, entry can be NULL */ + if (entry) + __jump_label_update(key, entry, enable); + +#ifdef CONFIG_MODULES + __jump_label_mod_update(key, enable); +#endif +} + #endif diff --git a/kernel/perf_event.c b/kernel/perf_event.c index c75925c..d665e92 100644 --- a/kernel/perf_event.c +++ b/kernel/perf_event.c @@ -125,7 +125,7 @@ enum event_type_t { * perf_sched_events : >0 events exist * perf_cgroup_events: >0 per-cpu cgroup events exist on this cpu */ -atomic_t perf_sched_events __read_mostly; +struct jump_label_key perf_sched_events __read_mostly; static DEFINE_PER_CPU(atomic_t, perf_cgroup_events); static atomic_t nr_mmap_events __read_mostly; @@ -5417,7 +5417,7 @@ fail: return err; } -atomic_t perf_swevent_enabled[PERF_COUNT_SW_MAX]; +struct jump_label_key perf_swevent_enabled[PERF_COUNT_SW_MAX]; static void sw_perf_event_destroy(struct perf_event *event) { diff --git a/kernel/tracepoint.c b/kernel/tracepoint.c index 68187af..b219f14 100644 --- a/kernel/tracepoint.c +++ b/kernel/tracepoint.c @@ -251,9 +251,9 @@ static void set_tracepoint(struct tracepoint_entry **entry, { WARN_ON(strcmp((*entry)->name, elem->name) != 0); - if (elem->regfunc && !elem->state && active) + if (elem->regfunc && !jump_label_enabled(&elem->key) && active) elem->regfunc(); - else if (elem->unregfunc && elem->state && !active) + else if (elem->unregfunc && jump_label_enabled(&elem->key) && !active) elem->unregfunc(); /* @@ -264,13 +264,10 @@ static void set_tracepoint(struct tracepoint_entry **entry, * is used. */ rcu_assign_pointer(elem->funcs, (*entry)->funcs); - if (!elem->state && active) { - jump_label_enable(&elem->state); - elem->state = active; - } else if (elem->state && !active) { - jump_label_disable(&elem->state); - elem->state = active; - } + if (active && !jump_label_enabled(&elem->key)) + jump_label_inc(&elem->key); + else if (!active && jump_label_enabled(&elem->key)) + jump_label_dec(&elem->key); } /* @@ -281,13 +278,11 @@ static void set_tracepoint(struct tracepoint_entry **entry, */ static void disable_tracepoint(struct tracepoint *elem) { - if (elem->unregfunc && elem->state) + if (elem->unregfunc && jump_label_enabled(&elem->key)) elem->unregfunc(); - if (elem->state) { - jump_label_disable(&elem->state); - elem->state = 0; - } + if (jump_label_enabled(&elem->key)) + jump_label_dec(&elem->key); rcu_assign_pointer(elem->funcs, NULL); } -- cgit v1.1 From f4ad9bd208c98f32a6f9136618e0b8bebe3fb370 Mon Sep 17 00:00:00 2001 From: Shaohua Li Date: Fri, 8 Apr 2011 12:53:09 +0800 Subject: sched: Eliminate dead code from wakeup_gran() calc_delta_fair() checks NICE_0_LOAD already, delete duplicate check. Signed-off-by: Shaohua Li Signed-off-by: Peter Zijlstra Cc: Mike Galbraith Link: http://lkml.kernel.org/r/1302238389.3981.92.camel@sli10-conroe Signed-off-by: Ingo Molnar --- kernel/sched_fair.c | 5 +---- 1 file changed, 1 insertion(+), 4 deletions(-) (limited to 'kernel') diff --git a/kernel/sched_fair.c b/kernel/sched_fair.c index 6fa833a..4ee50f0 100644 --- a/kernel/sched_fair.c +++ b/kernel/sched_fair.c @@ -1789,10 +1789,7 @@ wakeup_gran(struct sched_entity *curr, struct sched_entity *se) * This is especially important for buddies when the leftmost * task is higher priority than the buddy. */ - if (unlikely(se->load.weight != NICE_0_LOAD)) - gran = calc_delta_fair(gran, se); - - return gran; + return calc_delta_fair(gran, se); } /* -- cgit v1.1 From c4a8849af939082052d8117f9ea3e170a99ff232 Mon Sep 17 00:00:00 2001 From: Peter Zijlstra Date: Thu, 7 Apr 2011 14:09:42 +0200 Subject: sched: Remove obsolete arch_ prefixes Non weak static functions clearly are not arch specific, so remove the arch_ prefix. Signed-off-by: Peter Zijlstra Cc: Mike Galbraith Cc: Nick Piggin Cc: Linus Torvalds Cc: Andrew Morton Link: http://lkml.kernel.org/r/20110407122941.820460566@chello.nl Signed-off-by: Ingo Molnar --- kernel/sched.c | 14 +++++++------- 1 file changed, 7 insertions(+), 7 deletions(-) (limited to 'kernel') diff --git a/kernel/sched.c b/kernel/sched.c index 4801363..d3e183c 100644 --- a/kernel/sched.c +++ b/kernel/sched.c @@ -231,7 +231,7 @@ static void destroy_rt_bandwidth(struct rt_bandwidth *rt_b) #endif /* - * sched_domains_mutex serializes calls to arch_init_sched_domains, + * sched_domains_mutex serializes calls to init_sched_domains, * detach_destroy_domains and partition_sched_domains. */ static DEFINE_MUTEX(sched_domains_mutex); @@ -7670,7 +7670,7 @@ void free_sched_domains(cpumask_var_t doms[], unsigned int ndoms) * For now this just excludes isolated cpus, but could be used to * exclude other special cases in the future. */ -static int arch_init_sched_domains(const struct cpumask *cpu_map) +static int init_sched_domains(const struct cpumask *cpu_map) { int err; @@ -7687,7 +7687,7 @@ static int arch_init_sched_domains(const struct cpumask *cpu_map) return err; } -static void arch_destroy_sched_domains(const struct cpumask *cpu_map, +static void destroy_sched_domains(const struct cpumask *cpu_map, struct cpumask *tmpmask) { free_sched_groups(cpu_map, tmpmask); @@ -7706,7 +7706,7 @@ static void detach_destroy_domains(const struct cpumask *cpu_map) for_each_cpu(i, cpu_map) cpu_attach_domain(NULL, &def_root_domain, i); synchronize_sched(); - arch_destroy_sched_domains(cpu_map, to_cpumask(tmpmask)); + destroy_sched_domains(cpu_map, to_cpumask(tmpmask)); } /* handle null as "default" */ @@ -7815,7 +7815,7 @@ match2: } #if defined(CONFIG_SCHED_MC) || defined(CONFIG_SCHED_SMT) -static void arch_reinit_sched_domains(void) +static void reinit_sched_domains(void) { get_online_cpus(); @@ -7848,7 +7848,7 @@ static ssize_t sched_power_savings_store(const char *buf, size_t count, int smt) else sched_mc_power_savings = level; - arch_reinit_sched_domains(); + reinit_sched_domains(); return count; } @@ -7974,7 +7974,7 @@ void __init sched_init_smp(void) #endif get_online_cpus(); mutex_lock(&sched_domains_mutex); - arch_init_sched_domains(cpu_active_mask); + init_sched_domains(cpu_active_mask); cpumask_andnot(non_isolated_cpus, cpu_possible_mask, cpu_isolated_map); if (cpumask_empty(non_isolated_cpus)) cpumask_set_cpu(smp_processor_id(), non_isolated_cpus); -- cgit v1.1 From d274cb30f4a08045492d3f0c47cdf1a25668b1f5 Mon Sep 17 00:00:00 2001 From: Peter Zijlstra Date: Thu, 7 Apr 2011 14:09:43 +0200 Subject: sched: Simplify ->cpu_power initialization The code in update_group_power() does what init_sched_groups_power() does and more, so remove the special init_ code and call the generic code instead. Also move the sd->span_weight initialization because update_group_power() needs it. Signed-off-by: Peter Zijlstra Cc: Mike Galbraith Cc: Nick Piggin Cc: Linus Torvalds Cc: Andrew Morton Link: http://lkml.kernel.org/r/20110407122941.875856012@chello.nl Signed-off-by: Ingo Molnar --- kernel/sched.c | 44 +++++--------------------------------------- 1 file changed, 5 insertions(+), 39 deletions(-) (limited to 'kernel') diff --git a/kernel/sched.c b/kernel/sched.c index d3e183c..50d5fd3 100644 --- a/kernel/sched.c +++ b/kernel/sched.c @@ -6679,9 +6679,6 @@ cpu_attach_domain(struct sched_domain *sd, struct root_domain *rd, int cpu) struct rq *rq = cpu_rq(cpu); struct sched_domain *tmp; - for (tmp = sd; tmp; tmp = tmp->parent) - tmp->span_weight = cpumask_weight(sched_domain_span(tmp)); - /* Remove the sched domains which do not contribute to scheduling. */ for (tmp = sd; tmp; ) { struct sched_domain *parent = tmp->parent; @@ -7159,11 +7156,6 @@ static void free_sched_groups(const struct cpumask *cpu_map, */ static void init_sched_groups_power(int cpu, struct sched_domain *sd) { - struct sched_domain *child; - struct sched_group *group; - long power; - int weight; - WARN_ON(!sd || !sd->groups); if (cpu != group_first_cpu(sd->groups)) @@ -7171,36 +7163,7 @@ static void init_sched_groups_power(int cpu, struct sched_domain *sd) sd->groups->group_weight = cpumask_weight(sched_group_cpus(sd->groups)); - child = sd->child; - - sd->groups->cpu_power = 0; - - if (!child) { - power = SCHED_LOAD_SCALE; - weight = cpumask_weight(sched_domain_span(sd)); - /* - * SMT siblings share the power of a single core. - * Usually multiple threads get a better yield out of - * that one core than a single thread would have, - * reflect that in sd->smt_gain. - */ - if ((sd->flags & SD_SHARE_CPUPOWER) && weight > 1) { - power *= sd->smt_gain; - power /= weight; - power >>= SCHED_LOAD_SHIFT; - } - sd->groups->cpu_power += power; - return; - } - - /* - * Add cpu_power of each child group to this groups cpu_power. - */ - group = child->groups; - do { - sd->groups->cpu_power += group->cpu_power; - group = group->next; - } while (group != child->groups); + update_group_power(sd, cpu); } /* @@ -7507,7 +7470,7 @@ static int __build_sched_domains(const struct cpumask *cpu_map, { enum s_alloc alloc_state = sa_none; struct s_data d; - struct sched_domain *sd; + struct sched_domain *sd, *tmp; int i; #ifdef CONFIG_NUMA d.sd_allnodes = 0; @@ -7530,6 +7493,9 @@ static int __build_sched_domains(const struct cpumask *cpu_map, sd = __build_book_sched_domain(&d, cpu_map, attr, sd, i); sd = __build_mc_sched_domain(&d, cpu_map, attr, sd, i); sd = __build_smt_sched_domain(&d, cpu_map, attr, sd, i); + + for (tmp = sd; tmp; tmp = tmp->parent) + tmp->span_weight = cpumask_weight(sched_domain_span(tmp)); } for_each_cpu(i, cpu_map) { -- cgit v1.1 From a06dadbec5c5df0bf3a35f33616f67d10ca9ba28 Mon Sep 17 00:00:00 2001 From: Peter Zijlstra Date: Thu, 7 Apr 2011 14:09:44 +0200 Subject: sched: Simplify build_sched_groups() Notice that the mask being computed is the same as the domain span we just computed. By using the domain_span we can avoid some mask allocations and computations. Signed-off-by: Peter Zijlstra Cc: Mike Galbraith Cc: Nick Piggin Cc: Linus Torvalds Cc: Andrew Morton Link: http://lkml.kernel.org/r/20110407122941.925028189@chello.nl Signed-off-by: Ingo Molnar --- kernel/sched.c | 52 ++++++++++++++++------------------------------------ 1 file changed, 16 insertions(+), 36 deletions(-) (limited to 'kernel') diff --git a/kernel/sched.c b/kernel/sched.c index 50d5fd3..e3818f1 100644 --- a/kernel/sched.c +++ b/kernel/sched.c @@ -6866,9 +6866,6 @@ struct s_data { cpumask_var_t notcovered; #endif cpumask_var_t nodemask; - cpumask_var_t this_sibling_map; - cpumask_var_t this_core_map; - cpumask_var_t this_book_map; cpumask_var_t send_covered; cpumask_var_t tmpmask; struct sched_group **sched_group_nodes; @@ -6880,9 +6877,6 @@ enum s_alloc { sa_rootdomain, sa_tmpmask, sa_send_covered, - sa_this_book_map, - sa_this_core_map, - sa_this_sibling_map, sa_nodemask, sa_sched_group_nodes, #ifdef CONFIG_NUMA @@ -7251,12 +7245,6 @@ static void __free_domain_allocs(struct s_data *d, enum s_alloc what, free_cpumask_var(d->tmpmask); /* fall through */ case sa_send_covered: free_cpumask_var(d->send_covered); /* fall through */ - case sa_this_book_map: - free_cpumask_var(d->this_book_map); /* fall through */ - case sa_this_core_map: - free_cpumask_var(d->this_core_map); /* fall through */ - case sa_this_sibling_map: - free_cpumask_var(d->this_sibling_map); /* fall through */ case sa_nodemask: free_cpumask_var(d->nodemask); /* fall through */ case sa_sched_group_nodes: @@ -7295,14 +7283,8 @@ static enum s_alloc __visit_domain_allocation_hell(struct s_data *d, #endif if (!alloc_cpumask_var(&d->nodemask, GFP_KERNEL)) return sa_sched_group_nodes; - if (!alloc_cpumask_var(&d->this_sibling_map, GFP_KERNEL)) - return sa_nodemask; - if (!alloc_cpumask_var(&d->this_core_map, GFP_KERNEL)) - return sa_this_sibling_map; - if (!alloc_cpumask_var(&d->this_book_map, GFP_KERNEL)) - return sa_this_core_map; if (!alloc_cpumask_var(&d->send_covered, GFP_KERNEL)) - return sa_this_book_map; + return sa_nodemask; if (!alloc_cpumask_var(&d->tmpmask, GFP_KERNEL)) return sa_send_covered; d->rd = alloc_rootdomain(); @@ -7414,39 +7396,40 @@ static struct sched_domain *__build_smt_sched_domain(struct s_data *d, static void build_sched_groups(struct s_data *d, enum sched_domain_level l, const struct cpumask *cpu_map, int cpu) { + struct sched_domain *sd; + switch (l) { #ifdef CONFIG_SCHED_SMT case SD_LV_SIBLING: /* set up CPU (sibling) groups */ - cpumask_and(d->this_sibling_map, cpu_map, - topology_thread_cpumask(cpu)); - if (cpu == cpumask_first(d->this_sibling_map)) - init_sched_build_groups(d->this_sibling_map, cpu_map, + sd = &per_cpu(cpu_domains, cpu).sd; + if (cpu == cpumask_first(sched_domain_span(sd))) + init_sched_build_groups(sched_domain_span(sd), cpu_map, &cpu_to_cpu_group, d->send_covered, d->tmpmask); break; #endif #ifdef CONFIG_SCHED_MC case SD_LV_MC: /* set up multi-core groups */ - cpumask_and(d->this_core_map, cpu_map, cpu_coregroup_mask(cpu)); - if (cpu == cpumask_first(d->this_core_map)) - init_sched_build_groups(d->this_core_map, cpu_map, + sd = &per_cpu(core_domains, cpu).sd; + if (cpu == cpumask_first(sched_domain_span(sd))) + init_sched_build_groups(sched_domain_span(sd), cpu_map, &cpu_to_core_group, d->send_covered, d->tmpmask); break; #endif #ifdef CONFIG_SCHED_BOOK case SD_LV_BOOK: /* set up book groups */ - cpumask_and(d->this_book_map, cpu_map, cpu_book_mask(cpu)); - if (cpu == cpumask_first(d->this_book_map)) - init_sched_build_groups(d->this_book_map, cpu_map, + sd = &per_cpu(book_domains, cpu).sd; + if (cpu == cpumask_first(sched_domain_span(sd))) + init_sched_build_groups(sched_domain_span(sd), cpu_map, &cpu_to_book_group, d->send_covered, d->tmpmask); break; #endif case SD_LV_CPU: /* set up physical groups */ - cpumask_and(d->nodemask, cpumask_of_node(cpu), cpu_map); - if (!cpumask_empty(d->nodemask)) - init_sched_build_groups(d->nodemask, cpu_map, + sd = &per_cpu(phys_domains, cpu).sd; + if (cpu == cpumask_first(sched_domain_span(sd))) + init_sched_build_groups(sched_domain_span(sd), cpu_map, &cpu_to_phys_group, d->send_covered, d->tmpmask); break; @@ -7502,11 +7485,8 @@ static int __build_sched_domains(const struct cpumask *cpu_map, build_sched_groups(&d, SD_LV_SIBLING, cpu_map, i); build_sched_groups(&d, SD_LV_BOOK, cpu_map, i); build_sched_groups(&d, SD_LV_MC, cpu_map, i); - } - - /* Set up physical groups */ - for (i = 0; i < nr_node_ids; i++) build_sched_groups(&d, SD_LV_CPU, cpu_map, i); + } #ifdef CONFIG_NUMA /* Set up node groups */ -- cgit v1.1 From cd4ea6ae3982f6861da3b510e69cbc194f331d83 Mon Sep 17 00:00:00 2001 From: Peter Zijlstra Date: Thu, 7 Apr 2011 14:09:45 +0200 Subject: sched: Change NODE sched_domain group creation The NODE sched_domain is 'special' in that it allocates sched_groups per CPU, instead of sharing the sched_groups between all CPUs. While this might have some benefits on large NUMA and avoid remote memory accesses when iterating the sched_groups, this does break current code that assumes sched_groups are shared between all sched_domains (since the dynamic cpu_power patches). So refactor the NODE groups to behave like all other groups. (The ALLNODES domain again shared its groups across the CPUs for some reason). If someone does measure a performance decrease due to this change we need to revisit this and come up with another way to have both dynamic cpu_power and NUMA work nice together. Signed-off-by: Peter Zijlstra Cc: Mike Galbraith Cc: Nick Piggin Cc: Linus Torvalds Cc: Andrew Morton Link: http://lkml.kernel.org/r/20110407122941.978111700@chello.nl Signed-off-by: Ingo Molnar --- kernel/sched.c | 229 ++++++++------------------------------------------------- 1 file changed, 32 insertions(+), 197 deletions(-) (limited to 'kernel') diff --git a/kernel/sched.c b/kernel/sched.c index e3818f1..72d561f 100644 --- a/kernel/sched.c +++ b/kernel/sched.c @@ -6861,29 +6861,18 @@ struct static_sched_domain { struct s_data { #ifdef CONFIG_NUMA int sd_allnodes; - cpumask_var_t domainspan; - cpumask_var_t covered; - cpumask_var_t notcovered; #endif cpumask_var_t nodemask; cpumask_var_t send_covered; cpumask_var_t tmpmask; - struct sched_group **sched_group_nodes; struct root_domain *rd; }; enum s_alloc { - sa_sched_groups = 0, sa_rootdomain, sa_tmpmask, sa_send_covered, sa_nodemask, - sa_sched_group_nodes, -#ifdef CONFIG_NUMA - sa_notcovered, - sa_covered, - sa_domainspan, -#endif sa_none, }; @@ -6979,18 +6968,10 @@ cpu_to_phys_group(int cpu, const struct cpumask *cpu_map, } #ifdef CONFIG_NUMA -/* - * The init_sched_build_groups can't handle what we want to do with node - * groups, so roll our own. Now each node has its own list of groups which - * gets dynamically allocated. - */ static DEFINE_PER_CPU(struct static_sched_domain, node_domains); -static struct sched_group ***sched_group_nodes_bycpu; - -static DEFINE_PER_CPU(struct static_sched_domain, allnodes_domains); -static DEFINE_PER_CPU(struct static_sched_group, sched_group_allnodes); +static DEFINE_PER_CPU(struct static_sched_group, sched_group_node); -static int cpu_to_allnodes_group(int cpu, const struct cpumask *cpu_map, +static int cpu_to_node_group(int cpu, const struct cpumask *cpu_map, struct sched_group **sg, struct cpumask *nodemask) { @@ -7000,142 +6981,27 @@ static int cpu_to_allnodes_group(int cpu, const struct cpumask *cpu_map, group = cpumask_first(nodemask); if (sg) - *sg = &per_cpu(sched_group_allnodes, group).sg; + *sg = &per_cpu(sched_group_node, group).sg; return group; } -static void init_numa_sched_groups_power(struct sched_group *group_head) -{ - struct sched_group *sg = group_head; - int j; - - if (!sg) - return; - do { - for_each_cpu(j, sched_group_cpus(sg)) { - struct sched_domain *sd; - - sd = &per_cpu(phys_domains, j).sd; - if (j != group_first_cpu(sd->groups)) { - /* - * Only add "power" once for each - * physical package. - */ - continue; - } - - sg->cpu_power += sd->groups->cpu_power; - } - sg = sg->next; - } while (sg != group_head); -} +static DEFINE_PER_CPU(struct static_sched_domain, allnodes_domains); +static DEFINE_PER_CPU(struct static_sched_group, sched_group_allnodes); -static int build_numa_sched_groups(struct s_data *d, - const struct cpumask *cpu_map, int num) +static int cpu_to_allnodes_group(int cpu, const struct cpumask *cpu_map, + struct sched_group **sg, + struct cpumask *nodemask) { - struct sched_domain *sd; - struct sched_group *sg, *prev; - int n, j; - - cpumask_clear(d->covered); - cpumask_and(d->nodemask, cpumask_of_node(num), cpu_map); - if (cpumask_empty(d->nodemask)) { - d->sched_group_nodes[num] = NULL; - goto out; - } - - sched_domain_node_span(num, d->domainspan); - cpumask_and(d->domainspan, d->domainspan, cpu_map); - - sg = kmalloc_node(sizeof(struct sched_group) + cpumask_size(), - GFP_KERNEL, num); - if (!sg) { - printk(KERN_WARNING "Can not alloc domain group for node %d\n", - num); - return -ENOMEM; - } - d->sched_group_nodes[num] = sg; - - for_each_cpu(j, d->nodemask) { - sd = &per_cpu(node_domains, j).sd; - sd->groups = sg; - } + int group; - sg->cpu_power = 0; - cpumask_copy(sched_group_cpus(sg), d->nodemask); - sg->next = sg; - cpumask_or(d->covered, d->covered, d->nodemask); + cpumask_and(nodemask, cpumask_of_node(cpu_to_node(cpu)), cpu_map); + group = cpumask_first(nodemask); - prev = sg; - for (j = 0; j < nr_node_ids; j++) { - n = (num + j) % nr_node_ids; - cpumask_complement(d->notcovered, d->covered); - cpumask_and(d->tmpmask, d->notcovered, cpu_map); - cpumask_and(d->tmpmask, d->tmpmask, d->domainspan); - if (cpumask_empty(d->tmpmask)) - break; - cpumask_and(d->tmpmask, d->tmpmask, cpumask_of_node(n)); - if (cpumask_empty(d->tmpmask)) - continue; - sg = kmalloc_node(sizeof(struct sched_group) + cpumask_size(), - GFP_KERNEL, num); - if (!sg) { - printk(KERN_WARNING - "Can not alloc domain group for node %d\n", j); - return -ENOMEM; - } - sg->cpu_power = 0; - cpumask_copy(sched_group_cpus(sg), d->tmpmask); - sg->next = prev->next; - cpumask_or(d->covered, d->covered, d->tmpmask); - prev->next = sg; - prev = sg; - } -out: - return 0; + if (sg) + *sg = &per_cpu(sched_group_allnodes, group).sg; + return group; } -#endif /* CONFIG_NUMA */ - -#ifdef CONFIG_NUMA -/* Free memory allocated for various sched_group structures */ -static void free_sched_groups(const struct cpumask *cpu_map, - struct cpumask *nodemask) -{ - int cpu, i; - for_each_cpu(cpu, cpu_map) { - struct sched_group **sched_group_nodes - = sched_group_nodes_bycpu[cpu]; - - if (!sched_group_nodes) - continue; - - for (i = 0; i < nr_node_ids; i++) { - struct sched_group *oldsg, *sg = sched_group_nodes[i]; - - cpumask_and(nodemask, cpumask_of_node(i), cpu_map); - if (cpumask_empty(nodemask)) - continue; - - if (sg == NULL) - continue; - sg = sg->next; -next_sg: - oldsg = sg; - sg = sg->next; - kfree(oldsg); - if (oldsg != sched_group_nodes[i]) - goto next_sg; - } - kfree(sched_group_nodes); - sched_group_nodes_bycpu[cpu] = NULL; - } -} -#else /* !CONFIG_NUMA */ -static void free_sched_groups(const struct cpumask *cpu_map, - struct cpumask *nodemask) -{ -} #endif /* CONFIG_NUMA */ /* @@ -7236,9 +7102,6 @@ static void __free_domain_allocs(struct s_data *d, enum s_alloc what, const struct cpumask *cpu_map) { switch (what) { - case sa_sched_groups: - free_sched_groups(cpu_map, d->tmpmask); /* fall through */ - d->sched_group_nodes = NULL; case sa_rootdomain: free_rootdomain(d->rd); /* fall through */ case sa_tmpmask: @@ -7247,16 +7110,6 @@ static void __free_domain_allocs(struct s_data *d, enum s_alloc what, free_cpumask_var(d->send_covered); /* fall through */ case sa_nodemask: free_cpumask_var(d->nodemask); /* fall through */ - case sa_sched_group_nodes: -#ifdef CONFIG_NUMA - kfree(d->sched_group_nodes); /* fall through */ - case sa_notcovered: - free_cpumask_var(d->notcovered); /* fall through */ - case sa_covered: - free_cpumask_var(d->covered); /* fall through */ - case sa_domainspan: - free_cpumask_var(d->domainspan); /* fall through */ -#endif case sa_none: break; } @@ -7265,24 +7118,8 @@ static void __free_domain_allocs(struct s_data *d, enum s_alloc what, static enum s_alloc __visit_domain_allocation_hell(struct s_data *d, const struct cpumask *cpu_map) { -#ifdef CONFIG_NUMA - if (!alloc_cpumask_var(&d->domainspan, GFP_KERNEL)) - return sa_none; - if (!alloc_cpumask_var(&d->covered, GFP_KERNEL)) - return sa_domainspan; - if (!alloc_cpumask_var(&d->notcovered, GFP_KERNEL)) - return sa_covered; - /* Allocate the per-node list of sched groups */ - d->sched_group_nodes = kcalloc(nr_node_ids, - sizeof(struct sched_group *), GFP_KERNEL); - if (!d->sched_group_nodes) { - printk(KERN_WARNING "Can not alloc sched group node list\n"); - return sa_notcovered; - } - sched_group_nodes_bycpu[cpumask_first(cpu_map)] = d->sched_group_nodes; -#endif if (!alloc_cpumask_var(&d->nodemask, GFP_KERNEL)) - return sa_sched_group_nodes; + return sa_none; if (!alloc_cpumask_var(&d->send_covered, GFP_KERNEL)) return sa_nodemask; if (!alloc_cpumask_var(&d->tmpmask, GFP_KERNEL)) @@ -7322,6 +7159,7 @@ static struct sched_domain *__build_numa_sched_domains(struct s_data *d, if (parent) parent->child = sd; cpumask_and(sched_domain_span(sd), sched_domain_span(sd), cpu_map); + cpu_to_node_group(i, cpu_map, &sd->groups, d->tmpmask); #endif return sd; } @@ -7434,6 +7272,13 @@ static void build_sched_groups(struct s_data *d, enum sched_domain_level l, d->send_covered, d->tmpmask); break; #ifdef CONFIG_NUMA + case SD_LV_NODE: + sd = &per_cpu(node_domains, cpu).sd; + if (cpu == cpumask_first(sched_domain_span(sd))) + init_sched_build_groups(sched_domain_span(sd), cpu_map, + &cpu_to_node_group, + d->send_covered, d->tmpmask); + case SD_LV_ALLNODES: init_sched_build_groups(cpu_map, cpu_map, &cpu_to_allnodes_group, d->send_covered, d->tmpmask); @@ -7462,7 +7307,6 @@ static int __build_sched_domains(const struct cpumask *cpu_map, alloc_state = __visit_domain_allocation_hell(&d, cpu_map); if (alloc_state != sa_rootdomain) goto error; - alloc_state = sa_sched_groups; /* * Set up domains for cpus specified by the cpu_map. @@ -7486,16 +7330,13 @@ static int __build_sched_domains(const struct cpumask *cpu_map, build_sched_groups(&d, SD_LV_BOOK, cpu_map, i); build_sched_groups(&d, SD_LV_MC, cpu_map, i); build_sched_groups(&d, SD_LV_CPU, cpu_map, i); + build_sched_groups(&d, SD_LV_NODE, cpu_map, i); } #ifdef CONFIG_NUMA /* Set up node groups */ if (d.sd_allnodes) build_sched_groups(&d, SD_LV_ALLNODES, cpu_map, 0); - - for (i = 0; i < nr_node_ids; i++) - if (build_numa_sched_groups(&d, cpu_map, i)) - goto error; #endif /* Calculate CPU power for physical packages and nodes */ @@ -7524,15 +7365,16 @@ static int __build_sched_domains(const struct cpumask *cpu_map, } #ifdef CONFIG_NUMA - for (i = 0; i < nr_node_ids; i++) - init_numa_sched_groups_power(d.sched_group_nodes[i]); + for_each_cpu(i, cpu_map) { + sd = &per_cpu(node_domains, i).sd; + init_sched_groups_power(i, sd); + } if (d.sd_allnodes) { - struct sched_group *sg; - - cpu_to_allnodes_group(cpumask_first(cpu_map), cpu_map, &sg, - d.tmpmask); - init_numa_sched_groups_power(sg); + for_each_cpu(i, cpu_map) { + sd = &per_cpu(allnodes_domains, i).sd; + init_sched_groups_power(i, sd); + } } #endif @@ -7550,7 +7392,6 @@ static int __build_sched_domains(const struct cpumask *cpu_map, cpu_attach_domain(sd, d.rd, i); } - d.sched_group_nodes = NULL; /* don't free this we still need it */ __free_domain_allocs(&d, sa_tmpmask, cpu_map); return 0; @@ -7636,7 +7477,6 @@ static int init_sched_domains(const struct cpumask *cpu_map) static void destroy_sched_domains(const struct cpumask *cpu_map, struct cpumask *tmpmask) { - free_sched_groups(cpu_map, tmpmask); } /* @@ -7913,11 +7753,6 @@ void __init sched_init_smp(void) alloc_cpumask_var(&non_isolated_cpus, GFP_KERNEL); alloc_cpumask_var(&fallback_doms, GFP_KERNEL); -#if defined(CONFIG_NUMA) - sched_group_nodes_bycpu = kzalloc(nr_cpu_ids * sizeof(void **), - GFP_KERNEL); - BUG_ON(sched_group_nodes_bycpu == NULL); -#endif get_online_cpus(); mutex_lock(&sched_domains_mutex); init_sched_domains(cpu_active_mask); -- cgit v1.1 From 3739494e08da50c8a68d65eed5ba3012a54b40d4 Mon Sep 17 00:00:00 2001 From: Peter Zijlstra Date: Thu, 7 Apr 2011 14:09:46 +0200 Subject: sched: Clean up some ALLNODES code Signed-off-by: Peter Zijlstra Cc: Mike Galbraith Cc: Nick Piggin Cc: Linus Torvalds Cc: Andrew Morton Link: http://lkml.kernel.org/r/20110407122942.025636011@chello.nl Signed-off-by: Ingo Molnar --- kernel/sched.c | 11 ++++------- 1 file changed, 4 insertions(+), 7 deletions(-) (limited to 'kernel') diff --git a/kernel/sched.c b/kernel/sched.c index 72d561f..fa10cf7 100644 --- a/kernel/sched.c +++ b/kernel/sched.c @@ -7280,7 +7280,9 @@ static void build_sched_groups(struct s_data *d, enum sched_domain_level l, d->send_covered, d->tmpmask); case SD_LV_ALLNODES: - init_sched_build_groups(cpu_map, cpu_map, &cpu_to_allnodes_group, + if (cpu == cpumask_first(cpu_map)) + init_sched_build_groups(cpu_map, cpu_map, + &cpu_to_allnodes_group, d->send_covered, d->tmpmask); break; #endif @@ -7331,14 +7333,9 @@ static int __build_sched_domains(const struct cpumask *cpu_map, build_sched_groups(&d, SD_LV_MC, cpu_map, i); build_sched_groups(&d, SD_LV_CPU, cpu_map, i); build_sched_groups(&d, SD_LV_NODE, cpu_map, i); + build_sched_groups(&d, SD_LV_ALLNODES, cpu_map, i); } -#ifdef CONFIG_NUMA - /* Set up node groups */ - if (d.sd_allnodes) - build_sched_groups(&d, SD_LV_ALLNODES, cpu_map, 0); -#endif - /* Calculate CPU power for physical packages and nodes */ #ifdef CONFIG_SCHED_SMT for_each_cpu(i, cpu_map) { -- cgit v1.1 From 1cf51902546d60b8a7a6aba2dd557bd4ba8840ea Mon Sep 17 00:00:00 2001 From: Peter Zijlstra Date: Thu, 7 Apr 2011 14:09:47 +0200 Subject: sched: Simplify sched_group creation Instead of calling build_sched_groups() for each possible sched_domain we might have created, note that we can simply iterate the sched_domain tree and call it for each sched_domain present. Signed-off-by: Peter Zijlstra Cc: Mike Galbraith Cc: Nick Piggin Cc: Linus Torvalds Cc: Andrew Morton Link: http://lkml.kernel.org/r/20110407122942.077862519@chello.nl Signed-off-by: Ingo Molnar --- kernel/sched.c | 24 +++++------------------- 1 file changed, 5 insertions(+), 19 deletions(-) (limited to 'kernel') diff --git a/kernel/sched.c b/kernel/sched.c index fa10cf7..e66d24a 100644 --- a/kernel/sched.c +++ b/kernel/sched.c @@ -7231,15 +7231,12 @@ static struct sched_domain *__build_smt_sched_domain(struct s_data *d, return sd; } -static void build_sched_groups(struct s_data *d, enum sched_domain_level l, +static void build_sched_groups(struct s_data *d, struct sched_domain *sd, const struct cpumask *cpu_map, int cpu) { - struct sched_domain *sd; - - switch (l) { + switch (sd->level) { #ifdef CONFIG_SCHED_SMT case SD_LV_SIBLING: /* set up CPU (sibling) groups */ - sd = &per_cpu(cpu_domains, cpu).sd; if (cpu == cpumask_first(sched_domain_span(sd))) init_sched_build_groups(sched_domain_span(sd), cpu_map, &cpu_to_cpu_group, @@ -7248,7 +7245,6 @@ static void build_sched_groups(struct s_data *d, enum sched_domain_level l, #endif #ifdef CONFIG_SCHED_MC case SD_LV_MC: /* set up multi-core groups */ - sd = &per_cpu(core_domains, cpu).sd; if (cpu == cpumask_first(sched_domain_span(sd))) init_sched_build_groups(sched_domain_span(sd), cpu_map, &cpu_to_core_group, @@ -7257,7 +7253,6 @@ static void build_sched_groups(struct s_data *d, enum sched_domain_level l, #endif #ifdef CONFIG_SCHED_BOOK case SD_LV_BOOK: /* set up book groups */ - sd = &per_cpu(book_domains, cpu).sd; if (cpu == cpumask_first(sched_domain_span(sd))) init_sched_build_groups(sched_domain_span(sd), cpu_map, &cpu_to_book_group, @@ -7265,7 +7260,6 @@ static void build_sched_groups(struct s_data *d, enum sched_domain_level l, break; #endif case SD_LV_CPU: /* set up physical groups */ - sd = &per_cpu(phys_domains, cpu).sd; if (cpu == cpumask_first(sched_domain_span(sd))) init_sched_build_groups(sched_domain_span(sd), cpu_map, &cpu_to_phys_group, @@ -7273,7 +7267,6 @@ static void build_sched_groups(struct s_data *d, enum sched_domain_level l, break; #ifdef CONFIG_NUMA case SD_LV_NODE: - sd = &per_cpu(node_domains, cpu).sd; if (cpu == cpumask_first(sched_domain_span(sd))) init_sched_build_groups(sched_domain_span(sd), cpu_map, &cpu_to_node_group, @@ -7323,17 +7316,10 @@ static int __build_sched_domains(const struct cpumask *cpu_map, sd = __build_mc_sched_domain(&d, cpu_map, attr, sd, i); sd = __build_smt_sched_domain(&d, cpu_map, attr, sd, i); - for (tmp = sd; tmp; tmp = tmp->parent) + for (tmp = sd; tmp; tmp = tmp->parent) { tmp->span_weight = cpumask_weight(sched_domain_span(tmp)); - } - - for_each_cpu(i, cpu_map) { - build_sched_groups(&d, SD_LV_SIBLING, cpu_map, i); - build_sched_groups(&d, SD_LV_BOOK, cpu_map, i); - build_sched_groups(&d, SD_LV_MC, cpu_map, i); - build_sched_groups(&d, SD_LV_CPU, cpu_map, i); - build_sched_groups(&d, SD_LV_NODE, cpu_map, i); - build_sched_groups(&d, SD_LV_ALLNODES, cpu_map, i); + build_sched_groups(&d, tmp, cpu_map, i); + } } /* Calculate CPU power for physical packages and nodes */ -- cgit v1.1 From 21d42ccfd6c6c11f96c2acfd32a85cfc33514d3a Mon Sep 17 00:00:00 2001 From: Peter Zijlstra Date: Thu, 7 Apr 2011 14:09:48 +0200 Subject: sched: Simplify finding the lowest sched_domain Instead of relying on knowing the build order and various CONFIG_ flags simply remember the bottom most sched_domain when we created the domain hierarchy. Signed-off-by: Peter Zijlstra Cc: Mike Galbraith Cc: Nick Piggin Cc: Linus Torvalds Cc: Andrew Morton Link: http://lkml.kernel.org/r/20110407122942.134511046@chello.nl Signed-off-by: Ingo Molnar --- kernel/sched.c | 23 +++++++++++++---------- 1 file changed, 13 insertions(+), 10 deletions(-) (limited to 'kernel') diff --git a/kernel/sched.c b/kernel/sched.c index e66d24a..d6992bf 100644 --- a/kernel/sched.c +++ b/kernel/sched.c @@ -6865,11 +6865,13 @@ struct s_data { cpumask_var_t nodemask; cpumask_var_t send_covered; cpumask_var_t tmpmask; + struct sched_domain ** __percpu sd; struct root_domain *rd; }; enum s_alloc { sa_rootdomain, + sa_sd, sa_tmpmask, sa_send_covered, sa_nodemask, @@ -7104,6 +7106,8 @@ static void __free_domain_allocs(struct s_data *d, enum s_alloc what, switch (what) { case sa_rootdomain: free_rootdomain(d->rd); /* fall through */ + case sa_sd: + free_percpu(d->sd); /* fall through */ case sa_tmpmask: free_cpumask_var(d->tmpmask); /* fall through */ case sa_send_covered: @@ -7124,10 +7128,15 @@ static enum s_alloc __visit_domain_allocation_hell(struct s_data *d, return sa_nodemask; if (!alloc_cpumask_var(&d->tmpmask, GFP_KERNEL)) return sa_send_covered; + d->sd = alloc_percpu(struct sched_domain *); + if (!d->sd) { + printk(KERN_WARNING "Cannot alloc per-cpu pointers\n"); + return sa_tmpmask; + } d->rd = alloc_rootdomain(); if (!d->rd) { printk(KERN_WARNING "Cannot alloc root domain\n"); - return sa_tmpmask; + return sa_sd; } return sa_rootdomain; } @@ -7316,6 +7325,8 @@ static int __build_sched_domains(const struct cpumask *cpu_map, sd = __build_mc_sched_domain(&d, cpu_map, attr, sd, i); sd = __build_smt_sched_domain(&d, cpu_map, attr, sd, i); + *per_cpu_ptr(d.sd, i) = sd; + for (tmp = sd; tmp; tmp = tmp->parent) { tmp->span_weight = cpumask_weight(sched_domain_span(tmp)); build_sched_groups(&d, tmp, cpu_map, i); @@ -7363,15 +7374,7 @@ static int __build_sched_domains(const struct cpumask *cpu_map, /* Attach the domains */ for_each_cpu(i, cpu_map) { -#ifdef CONFIG_SCHED_SMT - sd = &per_cpu(cpu_domains, i).sd; -#elif defined(CONFIG_SCHED_MC) - sd = &per_cpu(core_domains, i).sd; -#elif defined(CONFIG_SCHED_BOOK) - sd = &per_cpu(book_domains, i).sd; -#else - sd = &per_cpu(phys_domains, i).sd; -#endif + sd = *per_cpu_ptr(d.sd, i); cpu_attach_domain(sd, d.rd, i); } -- cgit v1.1 From a9c9a9b6bff27ac9c746344a9c1a19bf3327002c Mon Sep 17 00:00:00 2001 From: Peter Zijlstra Date: Thu, 7 Apr 2011 14:09:49 +0200 Subject: sched: Simplify sched_groups_power initialization Again, instead of relying on knowing the possible domains and their order, simply rely on the sched_domain tree and whatever domains are present in there to initialize the sched_group cpu_power. Note: we need to iterate the CPU mask backwards because of the cpumask_first() condition for iterating up the tree. By iterating the mask backwards we ensure all groups of a domain are set-up before starting on the parent groups that rely on its children to be completely done. Signed-off-by: Peter Zijlstra Cc: Mike Galbraith Cc: Nick Piggin Cc: Linus Torvalds Cc: Andrew Morton Link: http://lkml.kernel.org/r/20110407122942.187335414@chello.nl Signed-off-by: Ingo Molnar --- kernel/sched.c | 39 +++++---------------------------------- 1 file changed, 5 insertions(+), 34 deletions(-) (limited to 'kernel') diff --git a/kernel/sched.c b/kernel/sched.c index d6992bf..1cca59e 100644 --- a/kernel/sched.c +++ b/kernel/sched.c @@ -7334,43 +7334,14 @@ static int __build_sched_domains(const struct cpumask *cpu_map, } /* Calculate CPU power for physical packages and nodes */ -#ifdef CONFIG_SCHED_SMT - for_each_cpu(i, cpu_map) { - sd = &per_cpu(cpu_domains, i).sd; - init_sched_groups_power(i, sd); - } -#endif -#ifdef CONFIG_SCHED_MC - for_each_cpu(i, cpu_map) { - sd = &per_cpu(core_domains, i).sd; - init_sched_groups_power(i, sd); - } -#endif -#ifdef CONFIG_SCHED_BOOK - for_each_cpu(i, cpu_map) { - sd = &per_cpu(book_domains, i).sd; - init_sched_groups_power(i, sd); - } -#endif - - for_each_cpu(i, cpu_map) { - sd = &per_cpu(phys_domains, i).sd; - init_sched_groups_power(i, sd); - } - -#ifdef CONFIG_NUMA - for_each_cpu(i, cpu_map) { - sd = &per_cpu(node_domains, i).sd; - init_sched_groups_power(i, sd); - } + for (i = nr_cpumask_bits-1; i >= 0; i--) { + if (!cpumask_test_cpu(i, cpu_map)) + continue; - if (d.sd_allnodes) { - for_each_cpu(i, cpu_map) { - sd = &per_cpu(allnodes_domains, i).sd; + sd = *per_cpu_ptr(d.sd, i); + for (; sd; sd = sd->parent) init_sched_groups_power(i, sd); - } } -#endif /* Attach the domains */ for_each_cpu(i, cpu_map) { -- cgit v1.1 From dce840a08702bd13a9a186e07e63d1ef82256b5e Mon Sep 17 00:00:00 2001 From: Peter Zijlstra Date: Thu, 7 Apr 2011 14:09:50 +0200 Subject: sched: Dynamically allocate sched_domain/sched_group data-structures Instead of relying on static allocations for the sched_domain and sched_group trees, dynamically allocate and RCU free them. Allocating this dynamically also allows for some build_sched_groups() simplification since we can now (like with other simplifications) rely on the sched_domain tree instead of hard-coded knowledge. One tricky to note is that detach_destroy_domains() needs to hold rcu_read_lock() over the entire tear-down, per-cpu is not sufficient since that can lead to partial sched_group existance (could possibly be solved by doing the tear-down backwards but this is much more robust). A concequence of the above is that we can no longer print the sched_domain debug stuff from cpu_attach_domain() since that might now run with preemption disabled (due to classic RCU etc.) and sched_domain_debug() does some GFP_KERNEL allocations. Another thing to note is that we now fully rely on normal RCU and not RCU-sched, this is because with the new and exiting RCU flavours we grew over the years BH doesn't necessarily hold off RCU-sched grace periods (-rt is known to break this). This would in fact already cause us grief since we do sched_domain/sched_group iterations from softirq context. This patch is somewhat larger than I would like it to be, but I didn't find any means of shrinking/splitting this. Signed-off-by: Peter Zijlstra Cc: Mike Galbraith Cc: Nick Piggin Cc: Linus Torvalds Cc: Andrew Morton Link: http://lkml.kernel.org/r/20110407122942.245307941@chello.nl Signed-off-by: Ingo Molnar --- kernel/sched.c | 479 +++++++++++++++++++++------------------------------- kernel/sched_fair.c | 30 +++- 2 files changed, 213 insertions(+), 296 deletions(-) (limited to 'kernel') diff --git a/kernel/sched.c b/kernel/sched.c index 1cca59e..6520484 100644 --- a/kernel/sched.c +++ b/kernel/sched.c @@ -417,6 +417,7 @@ struct rt_rq { */ struct root_domain { atomic_t refcount; + struct rcu_head rcu; cpumask_var_t span; cpumask_var_t online; @@ -571,7 +572,7 @@ static inline int cpu_of(struct rq *rq) #define rcu_dereference_check_sched_domain(p) \ rcu_dereference_check((p), \ - rcu_read_lock_sched_held() || \ + rcu_read_lock_held() || \ lockdep_is_held(&sched_domains_mutex)) /* @@ -6572,12 +6573,11 @@ sd_parent_degenerate(struct sched_domain *sd, struct sched_domain *parent) return 1; } -static void free_rootdomain(struct root_domain *rd) +static void free_rootdomain(struct rcu_head *rcu) { - synchronize_sched(); + struct root_domain *rd = container_of(rcu, struct root_domain, rcu); cpupri_cleanup(&rd->cpupri); - free_cpumask_var(rd->rto_mask); free_cpumask_var(rd->online); free_cpumask_var(rd->span); @@ -6618,7 +6618,7 @@ static void rq_attach_root(struct rq *rq, struct root_domain *rd) raw_spin_unlock_irqrestore(&rq->lock, flags); if (old_rd) - free_rootdomain(old_rd); + call_rcu_sched(&old_rd->rcu, free_rootdomain); } static int init_rootdomain(struct root_domain *rd) @@ -6669,6 +6669,25 @@ static struct root_domain *alloc_rootdomain(void) return rd; } +static void free_sched_domain(struct rcu_head *rcu) +{ + struct sched_domain *sd = container_of(rcu, struct sched_domain, rcu); + if (atomic_dec_and_test(&sd->groups->ref)) + kfree(sd->groups); + kfree(sd); +} + +static void destroy_sched_domain(struct sched_domain *sd, int cpu) +{ + call_rcu(&sd->rcu, free_sched_domain); +} + +static void destroy_sched_domains(struct sched_domain *sd, int cpu) +{ + for (; sd; sd = sd->parent) + destroy_sched_domain(sd, cpu); +} + /* * Attach the domain 'sd' to 'cpu' as its base domain. Callers must * hold the hotplug lock. @@ -6689,20 +6708,25 @@ cpu_attach_domain(struct sched_domain *sd, struct root_domain *rd, int cpu) tmp->parent = parent->parent; if (parent->parent) parent->parent->child = tmp; + destroy_sched_domain(parent, cpu); } else tmp = tmp->parent; } if (sd && sd_degenerate(sd)) { + tmp = sd; sd = sd->parent; + destroy_sched_domain(tmp, cpu); if (sd) sd->child = NULL; } - sched_domain_debug(sd, cpu); + /* sched_domain_debug(sd, cpu); */ rq_attach_root(rq, rd); + tmp = rq->sd; rcu_assign_pointer(rq->sd, sd); + destroy_sched_domains(tmp, cpu); } /* cpus with isolated domains */ @@ -6718,56 +6742,6 @@ static int __init isolated_cpu_setup(char *str) __setup("isolcpus=", isolated_cpu_setup); -/* - * init_sched_build_groups takes the cpumask we wish to span, and a pointer - * to a function which identifies what group(along with sched group) a CPU - * belongs to. The return value of group_fn must be a >= 0 and < nr_cpu_ids - * (due to the fact that we keep track of groups covered with a struct cpumask). - * - * init_sched_build_groups will build a circular linked list of the groups - * covered by the given span, and will set each group's ->cpumask correctly, - * and ->cpu_power to 0. - */ -static void -init_sched_build_groups(const struct cpumask *span, - const struct cpumask *cpu_map, - int (*group_fn)(int cpu, const struct cpumask *cpu_map, - struct sched_group **sg, - struct cpumask *tmpmask), - struct cpumask *covered, struct cpumask *tmpmask) -{ - struct sched_group *first = NULL, *last = NULL; - int i; - - cpumask_clear(covered); - - for_each_cpu(i, span) { - struct sched_group *sg; - int group = group_fn(i, cpu_map, &sg, tmpmask); - int j; - - if (cpumask_test_cpu(i, covered)) - continue; - - cpumask_clear(sched_group_cpus(sg)); - sg->cpu_power = 0; - - for_each_cpu(j, span) { - if (group_fn(j, cpu_map, NULL, tmpmask) != group) - continue; - - cpumask_set_cpu(j, covered); - cpumask_set_cpu(j, sched_group_cpus(sg)); - } - if (!first) - first = sg; - if (last) - last->next = sg; - last = sg; - } - last->next = first; -} - #define SD_NODES_PER_DOMAIN 16 #ifdef CONFIG_NUMA @@ -6858,154 +6832,96 @@ struct static_sched_domain { DECLARE_BITMAP(span, CONFIG_NR_CPUS); }; +struct sd_data { + struct sched_domain **__percpu sd; + struct sched_group **__percpu sg; +}; + struct s_data { #ifdef CONFIG_NUMA int sd_allnodes; #endif cpumask_var_t nodemask; cpumask_var_t send_covered; - cpumask_var_t tmpmask; struct sched_domain ** __percpu sd; + struct sd_data sdd[SD_LV_MAX]; struct root_domain *rd; }; enum s_alloc { sa_rootdomain, sa_sd, - sa_tmpmask, + sa_sd_storage, sa_send_covered, sa_nodemask, sa_none, }; /* - * SMT sched-domains: + * Assumes the sched_domain tree is fully constructed */ -#ifdef CONFIG_SCHED_SMT -static DEFINE_PER_CPU(struct static_sched_domain, cpu_domains); -static DEFINE_PER_CPU(struct static_sched_group, sched_groups); - -static int -cpu_to_cpu_group(int cpu, const struct cpumask *cpu_map, - struct sched_group **sg, struct cpumask *unused) +static int get_group(int cpu, struct sd_data *sdd, struct sched_group **sg) { - if (sg) - *sg = &per_cpu(sched_groups, cpu).sg; - return cpu; -} -#endif /* CONFIG_SCHED_SMT */ + struct sched_domain *sd = *per_cpu_ptr(sdd->sd, cpu); + struct sched_domain *child = sd->child; -/* - * multi-core sched-domains: - */ -#ifdef CONFIG_SCHED_MC -static DEFINE_PER_CPU(struct static_sched_domain, core_domains); -static DEFINE_PER_CPU(struct static_sched_group, sched_group_core); + if (child) + cpu = cpumask_first(sched_domain_span(child)); -static int -cpu_to_core_group(int cpu, const struct cpumask *cpu_map, - struct sched_group **sg, struct cpumask *mask) -{ - int group; -#ifdef CONFIG_SCHED_SMT - cpumask_and(mask, topology_thread_cpumask(cpu), cpu_map); - group = cpumask_first(mask); -#else - group = cpu; -#endif if (sg) - *sg = &per_cpu(sched_group_core, group).sg; - return group; + *sg = *per_cpu_ptr(sdd->sg, cpu); + + return cpu; } -#endif /* CONFIG_SCHED_MC */ /* - * book sched-domains: + * build_sched_groups takes the cpumask we wish to span, and a pointer + * to a function which identifies what group(along with sched group) a CPU + * belongs to. The return value of group_fn must be a >= 0 and < nr_cpu_ids + * (due to the fact that we keep track of groups covered with a struct cpumask). + * + * build_sched_groups will build a circular linked list of the groups + * covered by the given span, and will set each group's ->cpumask correctly, + * and ->cpu_power to 0. */ -#ifdef CONFIG_SCHED_BOOK -static DEFINE_PER_CPU(struct static_sched_domain, book_domains); -static DEFINE_PER_CPU(struct static_sched_group, sched_group_book); - -static int -cpu_to_book_group(int cpu, const struct cpumask *cpu_map, - struct sched_group **sg, struct cpumask *mask) -{ - int group = cpu; -#ifdef CONFIG_SCHED_MC - cpumask_and(mask, cpu_coregroup_mask(cpu), cpu_map); - group = cpumask_first(mask); -#elif defined(CONFIG_SCHED_SMT) - cpumask_and(mask, topology_thread_cpumask(cpu), cpu_map); - group = cpumask_first(mask); -#endif - if (sg) - *sg = &per_cpu(sched_group_book, group).sg; - return group; -} -#endif /* CONFIG_SCHED_BOOK */ - -static DEFINE_PER_CPU(struct static_sched_domain, phys_domains); -static DEFINE_PER_CPU(struct static_sched_group, sched_group_phys); - -static int -cpu_to_phys_group(int cpu, const struct cpumask *cpu_map, - struct sched_group **sg, struct cpumask *mask) +static void +build_sched_groups(struct sched_domain *sd, struct cpumask *covered) { - int group; -#ifdef CONFIG_SCHED_BOOK - cpumask_and(mask, cpu_book_mask(cpu), cpu_map); - group = cpumask_first(mask); -#elif defined(CONFIG_SCHED_MC) - cpumask_and(mask, cpu_coregroup_mask(cpu), cpu_map); - group = cpumask_first(mask); -#elif defined(CONFIG_SCHED_SMT) - cpumask_and(mask, topology_thread_cpumask(cpu), cpu_map); - group = cpumask_first(mask); -#else - group = cpu; -#endif - if (sg) - *sg = &per_cpu(sched_group_phys, group).sg; - return group; -} - -#ifdef CONFIG_NUMA -static DEFINE_PER_CPU(struct static_sched_domain, node_domains); -static DEFINE_PER_CPU(struct static_sched_group, sched_group_node); + struct sched_group *first = NULL, *last = NULL; + struct sd_data *sdd = sd->private; + const struct cpumask *span = sched_domain_span(sd); + int i; -static int cpu_to_node_group(int cpu, const struct cpumask *cpu_map, - struct sched_group **sg, - struct cpumask *nodemask) -{ - int group; + cpumask_clear(covered); - cpumask_and(nodemask, cpumask_of_node(cpu_to_node(cpu)), cpu_map); - group = cpumask_first(nodemask); + for_each_cpu(i, span) { + struct sched_group *sg; + int group = get_group(i, sdd, &sg); + int j; - if (sg) - *sg = &per_cpu(sched_group_node, group).sg; - return group; -} + if (cpumask_test_cpu(i, covered)) + continue; -static DEFINE_PER_CPU(struct static_sched_domain, allnodes_domains); -static DEFINE_PER_CPU(struct static_sched_group, sched_group_allnodes); + cpumask_clear(sched_group_cpus(sg)); + sg->cpu_power = 0; -static int cpu_to_allnodes_group(int cpu, const struct cpumask *cpu_map, - struct sched_group **sg, - struct cpumask *nodemask) -{ - int group; + for_each_cpu(j, span) { + if (get_group(j, sdd, NULL) != group) + continue; - cpumask_and(nodemask, cpumask_of_node(cpu_to_node(cpu)), cpu_map); - group = cpumask_first(nodemask); + cpumask_set_cpu(j, covered); + cpumask_set_cpu(j, sched_group_cpus(sg)); + } - if (sg) - *sg = &per_cpu(sched_group_allnodes, group).sg; - return group; + if (!first) + first = sg; + if (last) + last->next = sg; + last = sg; + } + last->next = first; } -#endif /* CONFIG_NUMA */ - /* * Initialize sched groups cpu_power. * @@ -7039,15 +6955,15 @@ static void init_sched_groups_power(int cpu, struct sched_domain *sd) # define SD_INIT_NAME(sd, type) do { } while (0) #endif -#define SD_INIT(sd, type) sd_init_##type(sd) - -#define SD_INIT_FUNC(type) \ -static noinline void sd_init_##type(struct sched_domain *sd) \ -{ \ - memset(sd, 0, sizeof(*sd)); \ - *sd = SD_##type##_INIT; \ - sd->level = SD_LV_##type; \ - SD_INIT_NAME(sd, type); \ +#define SD_INIT_FUNC(type) \ +static noinline struct sched_domain *sd_init_##type(struct s_data *d, int cpu) \ +{ \ + struct sched_domain *sd = *per_cpu_ptr(d->sdd[SD_LV_##type].sd, cpu); \ + *sd = SD_##type##_INIT; \ + sd->level = SD_LV_##type; \ + SD_INIT_NAME(sd, type); \ + sd->private = &d->sdd[SD_LV_##type]; \ + return sd; \ } SD_INIT_FUNC(CPU) @@ -7103,13 +7019,22 @@ static void set_domain_attribute(struct sched_domain *sd, static void __free_domain_allocs(struct s_data *d, enum s_alloc what, const struct cpumask *cpu_map) { + int i, j; + switch (what) { case sa_rootdomain: - free_rootdomain(d->rd); /* fall through */ + free_rootdomain(&d->rd->rcu); /* fall through */ case sa_sd: free_percpu(d->sd); /* fall through */ - case sa_tmpmask: - free_cpumask_var(d->tmpmask); /* fall through */ + case sa_sd_storage: + for (i = 0; i < SD_LV_MAX; i++) { + for_each_cpu(j, cpu_map) { + kfree(*per_cpu_ptr(d->sdd[i].sd, j)); + kfree(*per_cpu_ptr(d->sdd[i].sg, j)); + } + free_percpu(d->sdd[i].sd); + free_percpu(d->sdd[i].sg); + } /* fall through */ case sa_send_covered: free_cpumask_var(d->send_covered); /* fall through */ case sa_nodemask: @@ -7122,25 +7047,70 @@ static void __free_domain_allocs(struct s_data *d, enum s_alloc what, static enum s_alloc __visit_domain_allocation_hell(struct s_data *d, const struct cpumask *cpu_map) { + int i, j; + + memset(d, 0, sizeof(*d)); + if (!alloc_cpumask_var(&d->nodemask, GFP_KERNEL)) return sa_none; if (!alloc_cpumask_var(&d->send_covered, GFP_KERNEL)) return sa_nodemask; - if (!alloc_cpumask_var(&d->tmpmask, GFP_KERNEL)) - return sa_send_covered; - d->sd = alloc_percpu(struct sched_domain *); - if (!d->sd) { - printk(KERN_WARNING "Cannot alloc per-cpu pointers\n"); - return sa_tmpmask; + for (i = 0; i < SD_LV_MAX; i++) { + d->sdd[i].sd = alloc_percpu(struct sched_domain *); + if (!d->sdd[i].sd) + return sa_sd_storage; + + d->sdd[i].sg = alloc_percpu(struct sched_group *); + if (!d->sdd[i].sg) + return sa_sd_storage; + + for_each_cpu(j, cpu_map) { + struct sched_domain *sd; + struct sched_group *sg; + + sd = kzalloc_node(sizeof(struct sched_domain) + cpumask_size(), + GFP_KERNEL, cpu_to_node(j)); + if (!sd) + return sa_sd_storage; + + *per_cpu_ptr(d->sdd[i].sd, j) = sd; + + sg = kzalloc_node(sizeof(struct sched_group) + cpumask_size(), + GFP_KERNEL, cpu_to_node(j)); + if (!sg) + return sa_sd_storage; + + *per_cpu_ptr(d->sdd[i].sg, j) = sg; + } } + d->sd = alloc_percpu(struct sched_domain *); + if (!d->sd) + return sa_sd_storage; d->rd = alloc_rootdomain(); - if (!d->rd) { - printk(KERN_WARNING "Cannot alloc root domain\n"); + if (!d->rd) return sa_sd; - } return sa_rootdomain; } +/* + * NULL the sd_data elements we've used to build the sched_domain and + * sched_group structure so that the subsequent __free_domain_allocs() + * will not free the data we're using. + */ +static void claim_allocations(int cpu, struct sched_domain *sd) +{ + struct sd_data *sdd = sd->private; + struct sched_group *sg = sd->groups; + + WARN_ON_ONCE(*per_cpu_ptr(sdd->sd, cpu) != sd); + *per_cpu_ptr(sdd->sd, cpu) = NULL; + + if (cpu == cpumask_first(sched_group_cpus(sg))) { + WARN_ON_ONCE(*per_cpu_ptr(sdd->sg, cpu) != sg); + *per_cpu_ptr(sdd->sg, cpu) = NULL; + } +} + static struct sched_domain *__build_numa_sched_domains(struct s_data *d, const struct cpumask *cpu_map, struct sched_domain_attr *attr, int i) { @@ -7151,24 +7121,20 @@ static struct sched_domain *__build_numa_sched_domains(struct s_data *d, d->sd_allnodes = 0; if (cpumask_weight(cpu_map) > SD_NODES_PER_DOMAIN * cpumask_weight(d->nodemask)) { - sd = &per_cpu(allnodes_domains, i).sd; - SD_INIT(sd, ALLNODES); + sd = sd_init_ALLNODES(d, i); set_domain_attribute(sd, attr); cpumask_copy(sched_domain_span(sd), cpu_map); - cpu_to_allnodes_group(i, cpu_map, &sd->groups, d->tmpmask); d->sd_allnodes = 1; } parent = sd; - sd = &per_cpu(node_domains, i).sd; - SD_INIT(sd, NODE); + sd = sd_init_NODE(d, i); set_domain_attribute(sd, attr); sched_domain_node_span(cpu_to_node(i), sched_domain_span(sd)); sd->parent = parent; if (parent) parent->child = sd; cpumask_and(sched_domain_span(sd), sched_domain_span(sd), cpu_map); - cpu_to_node_group(i, cpu_map, &sd->groups, d->tmpmask); #endif return sd; } @@ -7178,14 +7144,12 @@ static struct sched_domain *__build_cpu_sched_domain(struct s_data *d, struct sched_domain *parent, int i) { struct sched_domain *sd; - sd = &per_cpu(phys_domains, i).sd; - SD_INIT(sd, CPU); + sd = sd_init_CPU(d, i); set_domain_attribute(sd, attr); cpumask_copy(sched_domain_span(sd), d->nodemask); sd->parent = parent; if (parent) parent->child = sd; - cpu_to_phys_group(i, cpu_map, &sd->groups, d->tmpmask); return sd; } @@ -7195,13 +7159,11 @@ static struct sched_domain *__build_book_sched_domain(struct s_data *d, { struct sched_domain *sd = parent; #ifdef CONFIG_SCHED_BOOK - sd = &per_cpu(book_domains, i).sd; - SD_INIT(sd, BOOK); + sd = sd_init_BOOK(d, i); set_domain_attribute(sd, attr); cpumask_and(sched_domain_span(sd), cpu_map, cpu_book_mask(i)); sd->parent = parent; parent->child = sd; - cpu_to_book_group(i, cpu_map, &sd->groups, d->tmpmask); #endif return sd; } @@ -7212,13 +7174,11 @@ static struct sched_domain *__build_mc_sched_domain(struct s_data *d, { struct sched_domain *sd = parent; #ifdef CONFIG_SCHED_MC - sd = &per_cpu(core_domains, i).sd; - SD_INIT(sd, MC); + sd = sd_init_MC(d, i); set_domain_attribute(sd, attr); cpumask_and(sched_domain_span(sd), cpu_map, cpu_coregroup_mask(i)); sd->parent = parent; parent->child = sd; - cpu_to_core_group(i, cpu_map, &sd->groups, d->tmpmask); #endif return sd; } @@ -7229,92 +7189,32 @@ static struct sched_domain *__build_smt_sched_domain(struct s_data *d, { struct sched_domain *sd = parent; #ifdef CONFIG_SCHED_SMT - sd = &per_cpu(cpu_domains, i).sd; - SD_INIT(sd, SIBLING); + sd = sd_init_SIBLING(d, i); set_domain_attribute(sd, attr); cpumask_and(sched_domain_span(sd), cpu_map, topology_thread_cpumask(i)); sd->parent = parent; parent->child = sd; - cpu_to_cpu_group(i, cpu_map, &sd->groups, d->tmpmask); #endif return sd; } -static void build_sched_groups(struct s_data *d, struct sched_domain *sd, - const struct cpumask *cpu_map, int cpu) -{ - switch (sd->level) { -#ifdef CONFIG_SCHED_SMT - case SD_LV_SIBLING: /* set up CPU (sibling) groups */ - if (cpu == cpumask_first(sched_domain_span(sd))) - init_sched_build_groups(sched_domain_span(sd), cpu_map, - &cpu_to_cpu_group, - d->send_covered, d->tmpmask); - break; -#endif -#ifdef CONFIG_SCHED_MC - case SD_LV_MC: /* set up multi-core groups */ - if (cpu == cpumask_first(sched_domain_span(sd))) - init_sched_build_groups(sched_domain_span(sd), cpu_map, - &cpu_to_core_group, - d->send_covered, d->tmpmask); - break; -#endif -#ifdef CONFIG_SCHED_BOOK - case SD_LV_BOOK: /* set up book groups */ - if (cpu == cpumask_first(sched_domain_span(sd))) - init_sched_build_groups(sched_domain_span(sd), cpu_map, - &cpu_to_book_group, - d->send_covered, d->tmpmask); - break; -#endif - case SD_LV_CPU: /* set up physical groups */ - if (cpu == cpumask_first(sched_domain_span(sd))) - init_sched_build_groups(sched_domain_span(sd), cpu_map, - &cpu_to_phys_group, - d->send_covered, d->tmpmask); - break; -#ifdef CONFIG_NUMA - case SD_LV_NODE: - if (cpu == cpumask_first(sched_domain_span(sd))) - init_sched_build_groups(sched_domain_span(sd), cpu_map, - &cpu_to_node_group, - d->send_covered, d->tmpmask); - - case SD_LV_ALLNODES: - if (cpu == cpumask_first(cpu_map)) - init_sched_build_groups(cpu_map, cpu_map, - &cpu_to_allnodes_group, - d->send_covered, d->tmpmask); - break; -#endif - default: - break; - } -} - /* * Build sched domains for a given set of cpus and attach the sched domains * to the individual cpus */ -static int __build_sched_domains(const struct cpumask *cpu_map, - struct sched_domain_attr *attr) +static int build_sched_domains(const struct cpumask *cpu_map, + struct sched_domain_attr *attr) { enum s_alloc alloc_state = sa_none; + struct sched_domain *sd; struct s_data d; - struct sched_domain *sd, *tmp; int i; -#ifdef CONFIG_NUMA - d.sd_allnodes = 0; -#endif alloc_state = __visit_domain_allocation_hell(&d, cpu_map); if (alloc_state != sa_rootdomain) goto error; - /* - * Set up domains for cpus specified by the cpu_map. - */ + /* Set up domains for cpus specified by the cpu_map. */ for_each_cpu(i, cpu_map) { cpumask_and(d.nodemask, cpumask_of_node(cpu_to_node(i)), cpu_map); @@ -7326,10 +7226,19 @@ static int __build_sched_domains(const struct cpumask *cpu_map, sd = __build_smt_sched_domain(&d, cpu_map, attr, sd, i); *per_cpu_ptr(d.sd, i) = sd; + } + + /* Build the groups for the domains */ + for_each_cpu(i, cpu_map) { + for (sd = *per_cpu_ptr(d.sd, i); sd; sd = sd->parent) { + sd->span_weight = cpumask_weight(sched_domain_span(sd)); + get_group(i, sd->private, &sd->groups); + atomic_inc(&sd->groups->ref); - for (tmp = sd; tmp; tmp = tmp->parent) { - tmp->span_weight = cpumask_weight(sched_domain_span(tmp)); - build_sched_groups(&d, tmp, cpu_map, i); + if (i != cpumask_first(sched_domain_span(sd))) + continue; + + build_sched_groups(sd, d.send_covered); } } @@ -7338,18 +7247,21 @@ static int __build_sched_domains(const struct cpumask *cpu_map, if (!cpumask_test_cpu(i, cpu_map)) continue; - sd = *per_cpu_ptr(d.sd, i); - for (; sd; sd = sd->parent) + for (sd = *per_cpu_ptr(d.sd, i); sd; sd = sd->parent) { + claim_allocations(i, sd); init_sched_groups_power(i, sd); + } } /* Attach the domains */ + rcu_read_lock(); for_each_cpu(i, cpu_map) { sd = *per_cpu_ptr(d.sd, i); cpu_attach_domain(sd, d.rd, i); } + rcu_read_unlock(); - __free_domain_allocs(&d, sa_tmpmask, cpu_map); + __free_domain_allocs(&d, sa_sd, cpu_map); return 0; error: @@ -7357,11 +7269,6 @@ error: return -ENOMEM; } -static int build_sched_domains(const struct cpumask *cpu_map) -{ - return __build_sched_domains(cpu_map, NULL); -} - static cpumask_var_t *doms_cur; /* current sched domains */ static int ndoms_cur; /* number of sched domains in 'doms_cur' */ static struct sched_domain_attr *dattr_cur; @@ -7425,31 +7332,24 @@ static int init_sched_domains(const struct cpumask *cpu_map) doms_cur = &fallback_doms; cpumask_andnot(doms_cur[0], cpu_map, cpu_isolated_map); dattr_cur = NULL; - err = build_sched_domains(doms_cur[0]); + err = build_sched_domains(doms_cur[0], NULL); register_sched_domain_sysctl(); return err; } -static void destroy_sched_domains(const struct cpumask *cpu_map, - struct cpumask *tmpmask) -{ -} - /* * Detach sched domains from a group of cpus specified in cpu_map * These cpus will now be attached to the NULL domain */ static void detach_destroy_domains(const struct cpumask *cpu_map) { - /* Save because hotplug lock held. */ - static DECLARE_BITMAP(tmpmask, CONFIG_NR_CPUS); int i; + rcu_read_lock(); for_each_cpu(i, cpu_map) cpu_attach_domain(NULL, &def_root_domain, i); - synchronize_sched(); - destroy_sched_domains(cpu_map, to_cpumask(tmpmask)); + rcu_read_unlock(); } /* handle null as "default" */ @@ -7538,8 +7438,7 @@ match1: goto match2; } /* no match - add a new doms_new */ - __build_sched_domains(doms_new[i], - dattr_new ? dattr_new + i : NULL); + build_sched_domains(doms_new[i], dattr_new ? dattr_new + i : NULL); match2: ; } diff --git a/kernel/sched_fair.c b/kernel/sched_fair.c index 4ee50f0..4a8ac7c 100644 --- a/kernel/sched_fair.c +++ b/kernel/sched_fair.c @@ -1622,6 +1622,7 @@ static int select_idle_sibling(struct task_struct *p, int target) /* * Otherwise, iterate the domains and find an elegible idle cpu. */ + rcu_read_lock(); for_each_domain(target, sd) { if (!(sd->flags & SD_SHARE_PKG_RESOURCES)) break; @@ -1641,6 +1642,7 @@ static int select_idle_sibling(struct task_struct *p, int target) cpumask_test_cpu(prev_cpu, sched_domain_span(sd))) break; } + rcu_read_unlock(); return target; } @@ -1673,6 +1675,7 @@ select_task_rq_fair(struct rq *rq, struct task_struct *p, int sd_flag, int wake_ new_cpu = prev_cpu; } + rcu_read_lock(); for_each_domain(cpu, tmp) { if (!(tmp->flags & SD_LOAD_BALANCE)) continue; @@ -1723,9 +1726,10 @@ select_task_rq_fair(struct rq *rq, struct task_struct *p, int sd_flag, int wake_ if (affine_sd) { if (cpu == prev_cpu || wake_affine(affine_sd, p, sync)) - return select_idle_sibling(p, cpu); - else - return select_idle_sibling(p, prev_cpu); + prev_cpu = cpu; + + new_cpu = select_idle_sibling(p, prev_cpu); + goto unlock; } while (sd) { @@ -1766,6 +1770,8 @@ select_task_rq_fair(struct rq *rq, struct task_struct *p, int sd_flag, int wake_ } /* while loop will break here if sd == NULL */ } +unlock: + rcu_read_unlock(); return new_cpu; } @@ -3462,6 +3468,7 @@ static void idle_balance(int this_cpu, struct rq *this_rq) raw_spin_unlock(&this_rq->lock); update_shares(this_cpu); + rcu_read_lock(); for_each_domain(this_cpu, sd) { unsigned long interval; int balance = 1; @@ -3483,6 +3490,7 @@ static void idle_balance(int this_cpu, struct rq *this_rq) break; } } + rcu_read_unlock(); raw_spin_lock(&this_rq->lock); @@ -3531,6 +3539,7 @@ static int active_load_balance_cpu_stop(void *data) double_lock_balance(busiest_rq, target_rq); /* Search for an sd spanning us and the target CPU. */ + rcu_read_lock(); for_each_domain(target_cpu, sd) { if ((sd->flags & SD_LOAD_BALANCE) && cpumask_test_cpu(busiest_cpu, sched_domain_span(sd))) @@ -3546,6 +3555,7 @@ static int active_load_balance_cpu_stop(void *data) else schedstat_inc(sd, alb_failed); } + rcu_read_unlock(); double_unlock_balance(busiest_rq, target_rq); out_unlock: busiest_rq->active_balance = 0; @@ -3672,6 +3682,7 @@ static int find_new_ilb(int cpu) { struct sched_domain *sd; struct sched_group *ilb_group; + int ilb = nr_cpu_ids; /* * Have idle load balancer selection from semi-idle packages only @@ -3687,20 +3698,25 @@ static int find_new_ilb(int cpu) if (cpumask_weight(nohz.idle_cpus_mask) < 2) goto out_done; + rcu_read_lock(); for_each_flag_domain(cpu, sd, SD_POWERSAVINGS_BALANCE) { ilb_group = sd->groups; do { - if (is_semi_idle_group(ilb_group)) - return cpumask_first(nohz.grp_idle_mask); + if (is_semi_idle_group(ilb_group)) { + ilb = cpumask_first(nohz.grp_idle_mask); + goto unlock; + } ilb_group = ilb_group->next; } while (ilb_group != sd->groups); } +unlock: + rcu_read_unlock(); out_done: - return nr_cpu_ids; + return ilb; } #else /* (CONFIG_SCHED_MC || CONFIG_SCHED_SMT) */ static inline int find_new_ilb(int call_cpu) @@ -3845,6 +3861,7 @@ static void rebalance_domains(int cpu, enum cpu_idle_type idle) update_shares(cpu); + rcu_read_lock(); for_each_domain(cpu, sd) { if (!(sd->flags & SD_LOAD_BALANCE)) continue; @@ -3890,6 +3907,7 @@ out: if (!balance) break; } + rcu_read_unlock(); /* * next_balance will be updated only when there is a need. -- cgit v1.1 From 822ff793c34a5d4c8b5f3f9ce932602233d96464 Mon Sep 17 00:00:00 2001 From: Peter Zijlstra Date: Thu, 7 Apr 2011 14:09:51 +0200 Subject: sched: Simplify the free path some If we check the root_domain reference count we can see if its been used or not, use this observation to simplify some of the return paths. Signed-off-by: Peter Zijlstra Cc: Mike Galbraith Cc: Nick Piggin Cc: Linus Torvalds Cc: Andrew Morton Link: http://lkml.kernel.org/r/20110407122942.298339503@chello.nl Signed-off-by: Ingo Molnar --- kernel/sched.c | 11 +++++------ 1 file changed, 5 insertions(+), 6 deletions(-) (limited to 'kernel') diff --git a/kernel/sched.c b/kernel/sched.c index 6520484..72c194c 100644 --- a/kernel/sched.c +++ b/kernel/sched.c @@ -7023,7 +7023,8 @@ static void __free_domain_allocs(struct s_data *d, enum s_alloc what, switch (what) { case sa_rootdomain: - free_rootdomain(&d->rd->rcu); /* fall through */ + if (!atomic_read(&d->rd->refcount)) + free_rootdomain(&d->rd->rcu); /* fall through */ case sa_sd: free_percpu(d->sd); /* fall through */ case sa_sd_storage: @@ -7208,7 +7209,7 @@ static int build_sched_domains(const struct cpumask *cpu_map, enum s_alloc alloc_state = sa_none; struct sched_domain *sd; struct s_data d; - int i; + int i, ret = -ENOMEM; alloc_state = __visit_domain_allocation_hell(&d, cpu_map); if (alloc_state != sa_rootdomain) @@ -7261,12 +7262,10 @@ static int build_sched_domains(const struct cpumask *cpu_map, } rcu_read_unlock(); - __free_domain_allocs(&d, sa_sd, cpu_map); - return 0; - + ret = 0; error: __free_domain_allocs(&d, alloc_state, cpu_map); - return -ENOMEM; + return ret; } static cpumask_var_t *doms_cur; /* current sched domains */ -- cgit v1.1 From a6c75f2f8d988ecfecf971f98f1cb6fc4de522fe Mon Sep 17 00:00:00 2001 From: Peter Zijlstra Date: Thu, 7 Apr 2011 14:09:52 +0200 Subject: sched: Avoid using sd->level Don't use sd->level for identifying properties of the domain. Signed-off-by: Peter Zijlstra Cc: Mike Galbraith Cc: Nick Piggin Cc: Linus Torvalds Cc: Andrew Morton Link: http://lkml.kernel.org/r/20110407122942.350174079@chello.nl Signed-off-by: Ingo Molnar --- kernel/sched_fair.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'kernel') diff --git a/kernel/sched_fair.c b/kernel/sched_fair.c index 4a8ac7c..9c5679c 100644 --- a/kernel/sched_fair.c +++ b/kernel/sched_fair.c @@ -2651,7 +2651,7 @@ fix_small_capacity(struct sched_domain *sd, struct sched_group *group) /* * Only siblings can have significantly less than SCHED_LOAD_SCALE */ - if (sd->level != SD_LV_SIBLING) + if (!(sd->flags & SD_SHARE_CPUPOWER)) return 0; /* -- cgit v1.1 From 3bd65a80affb9768b91f03c56dba46ee79525f9b Mon Sep 17 00:00:00 2001 From: Peter Zijlstra Date: Thu, 7 Apr 2011 14:09:54 +0200 Subject: sched: Simplify NODE/ALLNODES domain creation Don't treat ALLNODES/NODE different for difference's sake. Simply always create the ALLNODES domain and let the sd_degenerate() checks kill it when its redundant. This simplifies the code flow. Signed-off-by: Peter Zijlstra Cc: Mike Galbraith Cc: Nick Piggin Cc: Linus Torvalds Cc: Andrew Morton Link: http://lkml.kernel.org/r/20110407122942.455464579@chello.nl Signed-off-by: Ingo Molnar --- kernel/sched.c | 40 ++++++++++++++++++++++------------------ 1 file changed, 22 insertions(+), 18 deletions(-) (limited to 'kernel') diff --git a/kernel/sched.c b/kernel/sched.c index 72c194c..d395fe5 100644 --- a/kernel/sched.c +++ b/kernel/sched.c @@ -6838,9 +6838,6 @@ struct sd_data { }; struct s_data { -#ifdef CONFIG_NUMA - int sd_allnodes; -#endif cpumask_var_t nodemask; cpumask_var_t send_covered; struct sched_domain ** __percpu sd; @@ -7112,30 +7109,35 @@ static void claim_allocations(int cpu, struct sched_domain *sd) } } -static struct sched_domain *__build_numa_sched_domains(struct s_data *d, - const struct cpumask *cpu_map, struct sched_domain_attr *attr, int i) +static struct sched_domain *__build_allnodes_sched_domain(struct s_data *d, + const struct cpumask *cpu_map, struct sched_domain_attr *attr, + struct sched_domain *parent, int i) { struct sched_domain *sd = NULL; #ifdef CONFIG_NUMA - struct sched_domain *parent; - - d->sd_allnodes = 0; - if (cpumask_weight(cpu_map) > - SD_NODES_PER_DOMAIN * cpumask_weight(d->nodemask)) { - sd = sd_init_ALLNODES(d, i); - set_domain_attribute(sd, attr); - cpumask_copy(sched_domain_span(sd), cpu_map); - d->sd_allnodes = 1; - } - parent = sd; + sd = sd_init_ALLNODES(d, i); + set_domain_attribute(sd, attr); + cpumask_copy(sched_domain_span(sd), cpu_map); + sd->parent = parent; + if (parent) + parent->child = sd; +#endif + return sd; +} +static struct sched_domain *__build_node_sched_domain(struct s_data *d, + const struct cpumask *cpu_map, struct sched_domain_attr *attr, + struct sched_domain *parent, int i) +{ + struct sched_domain *sd = NULL; +#ifdef CONFIG_NUMA sd = sd_init_NODE(d, i); set_domain_attribute(sd, attr); sched_domain_node_span(cpu_to_node(i), sched_domain_span(sd)); + cpumask_and(sched_domain_span(sd), sched_domain_span(sd), cpu_map); sd->parent = parent; if (parent) parent->child = sd; - cpumask_and(sched_domain_span(sd), sched_domain_span(sd), cpu_map); #endif return sd; } @@ -7220,7 +7222,9 @@ static int build_sched_domains(const struct cpumask *cpu_map, cpumask_and(d.nodemask, cpumask_of_node(cpu_to_node(i)), cpu_map); - sd = __build_numa_sched_domains(&d, cpu_map, attr, i); + sd = NULL; + sd = __build_allnodes_sched_domain(&d, cpu_map, attr, sd, i); + sd = __build_node_sched_domain(&d, cpu_map, attr, sd, i); sd = __build_cpu_sched_domain(&d, cpu_map, attr, sd, i); sd = __build_book_sched_domain(&d, cpu_map, attr, sd, i); sd = __build_mc_sched_domain(&d, cpu_map, attr, sd, i); -- cgit v1.1 From bf28b253266ebd73c331dde24d64606afde32ceb Mon Sep 17 00:00:00 2001 From: Peter Zijlstra Date: Thu, 7 Apr 2011 14:09:55 +0200 Subject: sched: Remove nodemask allocation There's only one nodemask user left so remove it with a direct computation and save some memory and reduce some code-flow complexity. Signed-off-by: Peter Zijlstra Cc: Mike Galbraith Cc: Nick Piggin Cc: Linus Torvalds Cc: Andrew Morton Link: http://lkml.kernel.org/r/20110407122942.505608966@chello.nl Signed-off-by: Ingo Molnar --- kernel/sched.c | 14 +++----------- 1 file changed, 3 insertions(+), 11 deletions(-) (limited to 'kernel') diff --git a/kernel/sched.c b/kernel/sched.c index d395fe5..f4d3a62 100644 --- a/kernel/sched.c +++ b/kernel/sched.c @@ -6838,7 +6838,6 @@ struct sd_data { }; struct s_data { - cpumask_var_t nodemask; cpumask_var_t send_covered; struct sched_domain ** __percpu sd; struct sd_data sdd[SD_LV_MAX]; @@ -6850,7 +6849,6 @@ enum s_alloc { sa_sd, sa_sd_storage, sa_send_covered, - sa_nodemask, sa_none, }; @@ -7035,8 +7033,6 @@ static void __free_domain_allocs(struct s_data *d, enum s_alloc what, } /* fall through */ case sa_send_covered: free_cpumask_var(d->send_covered); /* fall through */ - case sa_nodemask: - free_cpumask_var(d->nodemask); /* fall through */ case sa_none: break; } @@ -7049,10 +7045,8 @@ static enum s_alloc __visit_domain_allocation_hell(struct s_data *d, memset(d, 0, sizeof(*d)); - if (!alloc_cpumask_var(&d->nodemask, GFP_KERNEL)) - return sa_none; if (!alloc_cpumask_var(&d->send_covered, GFP_KERNEL)) - return sa_nodemask; + return sa_none; for (i = 0; i < SD_LV_MAX; i++) { d->sdd[i].sd = alloc_percpu(struct sched_domain *); if (!d->sdd[i].sd) @@ -7149,7 +7143,8 @@ static struct sched_domain *__build_cpu_sched_domain(struct s_data *d, struct sched_domain *sd; sd = sd_init_CPU(d, i); set_domain_attribute(sd, attr); - cpumask_copy(sched_domain_span(sd), d->nodemask); + cpumask_and(sched_domain_span(sd), + cpumask_of_node(cpu_to_node(i)), cpu_map); sd->parent = parent; if (parent) parent->child = sd; @@ -7219,9 +7214,6 @@ static int build_sched_domains(const struct cpumask *cpu_map, /* Set up domains for cpus specified by the cpu_map. */ for_each_cpu(i, cpu_map) { - cpumask_and(d.nodemask, cpumask_of_node(cpu_to_node(i)), - cpu_map); - sd = NULL; sd = __build_allnodes_sched_domain(&d, cpu_map, attr, sd, i); sd = __build_node_sched_domain(&d, cpu_map, attr, sd, i); -- cgit v1.1 From 7dd04b730749f957c116f363524fd622b05e5141 Mon Sep 17 00:00:00 2001 From: Peter Zijlstra Date: Thu, 7 Apr 2011 14:09:56 +0200 Subject: sched: Remove some dead code Signed-off-by: Peter Zijlstra Cc: Mike Galbraith Cc: Nick Piggin Cc: Linus Torvalds Cc: Andrew Morton Link: http://lkml.kernel.org/r/20110407122942.553814623@chello.nl Signed-off-by: Ingo Molnar --- kernel/sched.c | 16 ---------------- 1 file changed, 16 deletions(-) (limited to 'kernel') diff --git a/kernel/sched.c b/kernel/sched.c index f4d3a62..5ec685c 100644 --- a/kernel/sched.c +++ b/kernel/sched.c @@ -6816,22 +6816,6 @@ static void sched_domain_node_span(int node, struct cpumask *span) int sched_smt_power_savings = 0, sched_mc_power_savings = 0; -/* - * The cpus mask in sched_group and sched_domain hangs off the end. - * - * ( See the the comments in include/linux/sched.h:struct sched_group - * and struct sched_domain. ) - */ -struct static_sched_group { - struct sched_group sg; - DECLARE_BITMAP(cpus, CONFIG_NR_CPUS); -}; - -struct static_sched_domain { - struct sched_domain sd; - DECLARE_BITMAP(span, CONFIG_NR_CPUS); -}; - struct sd_data { struct sched_domain **__percpu sd; struct sched_group **__percpu sg; -- cgit v1.1 From f96225fd51893b6650cffd5427f13f6b1b356488 Mon Sep 17 00:00:00 2001 From: Peter Zijlstra Date: Thu, 7 Apr 2011 14:09:57 +0200 Subject: sched: Create persistent sched_domains_tmpmask Since sched domain creation is fully serialized by the sched_domains_mutex we can create a single persistent tmpmask to use during domain creation. This removes the need for s_data::send_covered. Signed-off-by: Peter Zijlstra Cc: Mike Galbraith Cc: Nick Piggin Cc: Linus Torvalds Cc: Andrew Morton Link: http://lkml.kernel.org/r/20110407122942.607287405@chello.nl Signed-off-by: Ingo Molnar --- kernel/sched.c | 17 +++++++++-------- 1 file changed, 9 insertions(+), 8 deletions(-) (limited to 'kernel') diff --git a/kernel/sched.c b/kernel/sched.c index 5ec685c..fd73e91 100644 --- a/kernel/sched.c +++ b/kernel/sched.c @@ -6822,7 +6822,6 @@ struct sd_data { }; struct s_data { - cpumask_var_t send_covered; struct sched_domain ** __percpu sd; struct sd_data sdd[SD_LV_MAX]; struct root_domain *rd; @@ -6832,7 +6831,6 @@ enum s_alloc { sa_rootdomain, sa_sd, sa_sd_storage, - sa_send_covered, sa_none, }; @@ -6853,6 +6851,8 @@ static int get_group(int cpu, struct sd_data *sdd, struct sched_group **sg) return cpu; } +static cpumask_var_t sched_domains_tmpmask; /* sched_domains_mutex */ + /* * build_sched_groups takes the cpumask we wish to span, and a pointer * to a function which identifies what group(along with sched group) a CPU @@ -6864,13 +6864,17 @@ static int get_group(int cpu, struct sd_data *sdd, struct sched_group **sg) * and ->cpu_power to 0. */ static void -build_sched_groups(struct sched_domain *sd, struct cpumask *covered) +build_sched_groups(struct sched_domain *sd) { struct sched_group *first = NULL, *last = NULL; struct sd_data *sdd = sd->private; const struct cpumask *span = sched_domain_span(sd); + struct cpumask *covered; int i; + lockdep_assert_held(&sched_domains_mutex); + covered = sched_domains_tmpmask; + cpumask_clear(covered); for_each_cpu(i, span) { @@ -7015,8 +7019,6 @@ static void __free_domain_allocs(struct s_data *d, enum s_alloc what, free_percpu(d->sdd[i].sd); free_percpu(d->sdd[i].sg); } /* fall through */ - case sa_send_covered: - free_cpumask_var(d->send_covered); /* fall through */ case sa_none: break; } @@ -7029,8 +7031,6 @@ static enum s_alloc __visit_domain_allocation_hell(struct s_data *d, memset(d, 0, sizeof(*d)); - if (!alloc_cpumask_var(&d->send_covered, GFP_KERNEL)) - return sa_none; for (i = 0; i < SD_LV_MAX; i++) { d->sdd[i].sd = alloc_percpu(struct sched_domain *); if (!d->sdd[i].sd) @@ -7219,7 +7219,7 @@ static int build_sched_domains(const struct cpumask *cpu_map, if (i != cpumask_first(sched_domain_span(sd))) continue; - build_sched_groups(sd, d.send_covered); + build_sched_groups(sd); } } @@ -7896,6 +7896,7 @@ void __init sched_init(void) /* Allocate the nohz_cpu_mask if CONFIG_CPUMASK_OFFSTACK */ zalloc_cpumask_var(&nohz_cpu_mask, GFP_NOWAIT); + zalloc_cpumask_var(&sched_domains_tmpmask, GFP_NOWAIT); #ifdef CONFIG_SMP #ifdef CONFIG_NO_HZ zalloc_cpumask_var(&nohz.idle_cpus_mask, GFP_NOWAIT); -- cgit v1.1 From 4cb988395da6e16627a8be69729e50cd72ebb23e Mon Sep 17 00:00:00 2001 From: Peter Zijlstra Date: Thu, 7 Apr 2011 14:09:58 +0200 Subject: sched: Avoid allocations in sched_domain_debug() Since we're all serialized by sched_domains_mutex we can use sched_domains_tmpmask and avoid having to do allocations. This means we can use sched_domains_debug() for cpu_attach_domain() again. Signed-off-by: Peter Zijlstra Cc: Mike Galbraith Cc: Nick Piggin Cc: Linus Torvalds Cc: Andrew Morton Link: http://lkml.kernel.org/r/20110407122942.664347467@chello.nl Signed-off-by: Ingo Molnar --- kernel/sched.c | 17 +++++------------ 1 file changed, 5 insertions(+), 12 deletions(-) (limited to 'kernel') diff --git a/kernel/sched.c b/kernel/sched.c index fd73e91..35fc995 100644 --- a/kernel/sched.c +++ b/kernel/sched.c @@ -6395,6 +6395,8 @@ early_initcall(migration_init); #ifdef CONFIG_SMP +static cpumask_var_t sched_domains_tmpmask; /* sched_domains_mutex */ + #ifdef CONFIG_SCHED_DEBUG static __read_mostly int sched_domain_debug_enabled; @@ -6490,7 +6492,6 @@ static int sched_domain_debug_one(struct sched_domain *sd, int cpu, int level, static void sched_domain_debug(struct sched_domain *sd, int cpu) { - cpumask_var_t groupmask; int level = 0; if (!sched_domain_debug_enabled) @@ -6503,20 +6504,14 @@ static void sched_domain_debug(struct sched_domain *sd, int cpu) printk(KERN_DEBUG "CPU%d attaching sched-domain:\n", cpu); - if (!alloc_cpumask_var(&groupmask, GFP_KERNEL)) { - printk(KERN_DEBUG "Cannot load-balance (out of memory)\n"); - return; - } - for (;;) { - if (sched_domain_debug_one(sd, cpu, level, groupmask)) + if (sched_domain_debug_one(sd, cpu, level, sched_domains_tmpmask)) break; level++; sd = sd->parent; if (!sd) break; } - free_cpumask_var(groupmask); } #else /* !CONFIG_SCHED_DEBUG */ # define sched_domain_debug(sd, cpu) do { } while (0) @@ -6721,7 +6716,7 @@ cpu_attach_domain(struct sched_domain *sd, struct root_domain *rd, int cpu) sd->child = NULL; } - /* sched_domain_debug(sd, cpu); */ + sched_domain_debug(sd, cpu); rq_attach_root(rq, rd); tmp = rq->sd; @@ -6851,8 +6846,6 @@ static int get_group(int cpu, struct sd_data *sdd, struct sched_group **sg) return cpu; } -static cpumask_var_t sched_domains_tmpmask; /* sched_domains_mutex */ - /* * build_sched_groups takes the cpumask we wish to span, and a pointer * to a function which identifies what group(along with sched group) a CPU @@ -7896,8 +7889,8 @@ void __init sched_init(void) /* Allocate the nohz_cpu_mask if CONFIG_CPUMASK_OFFSTACK */ zalloc_cpumask_var(&nohz_cpu_mask, GFP_NOWAIT); - zalloc_cpumask_var(&sched_domains_tmpmask, GFP_NOWAIT); #ifdef CONFIG_SMP + zalloc_cpumask_var(&sched_domains_tmpmask, GFP_NOWAIT); #ifdef CONFIG_NO_HZ zalloc_cpumask_var(&nohz.idle_cpus_mask, GFP_NOWAIT); alloc_cpumask_var(&nohz.grp_idle_mask, GFP_NOWAIT); -- cgit v1.1 From d3081f52f29da1ba6c27685519a9222b39eac763 Mon Sep 17 00:00:00 2001 From: Peter Zijlstra Date: Thu, 7 Apr 2011 14:09:59 +0200 Subject: sched: Create proper cpu_$DOM_mask() functions In order to unify the sched domain creation more, create proper cpu_$DOM_mask() functions for those domains that didn't already have one. Use the sched_domains_tmpmask for the weird NUMA domain span. Signed-off-by: Peter Zijlstra Cc: Mike Galbraith Cc: Nick Piggin Cc: Linus Torvalds Cc: Andrew Morton Link: http://lkml.kernel.org/r/20110407122942.717702108@chello.nl Signed-off-by: Ingo Molnar --- kernel/sched.c | 22 +++++++++++++++++----- 1 file changed, 17 insertions(+), 5 deletions(-) (limited to 'kernel') diff --git a/kernel/sched.c b/kernel/sched.c index 35fc995..3ae1e02 100644 --- a/kernel/sched.c +++ b/kernel/sched.c @@ -6807,8 +6807,22 @@ static void sched_domain_node_span(int node, struct cpumask *span) cpumask_or(span, span, cpumask_of_node(next_node)); } } + +static const struct cpumask *cpu_node_mask(int cpu) +{ + lockdep_assert_held(&sched_domains_mutex); + + sched_domain_node_span(cpu_to_node(cpu), sched_domains_tmpmask); + + return sched_domains_tmpmask; +} #endif /* CONFIG_NUMA */ +static const struct cpumask *cpu_cpu_mask(int cpu) +{ + return cpumask_of_node(cpu_to_node(cpu)); +} + int sched_smt_power_savings = 0, sched_mc_power_savings = 0; struct sd_data { @@ -7088,7 +7102,7 @@ static struct sched_domain *__build_allnodes_sched_domain(struct s_data *d, #ifdef CONFIG_NUMA sd = sd_init_ALLNODES(d, i); set_domain_attribute(sd, attr); - cpumask_copy(sched_domain_span(sd), cpu_map); + cpumask_and(sched_domain_span(sd), cpu_map, cpu_possible_mask); sd->parent = parent; if (parent) parent->child = sd; @@ -7104,8 +7118,7 @@ static struct sched_domain *__build_node_sched_domain(struct s_data *d, #ifdef CONFIG_NUMA sd = sd_init_NODE(d, i); set_domain_attribute(sd, attr); - sched_domain_node_span(cpu_to_node(i), sched_domain_span(sd)); - cpumask_and(sched_domain_span(sd), sched_domain_span(sd), cpu_map); + cpumask_and(sched_domain_span(sd), cpu_map, cpu_node_mask(i)); sd->parent = parent; if (parent) parent->child = sd; @@ -7120,8 +7133,7 @@ static struct sched_domain *__build_cpu_sched_domain(struct s_data *d, struct sched_domain *sd; sd = sd_init_CPU(d, i); set_domain_attribute(sd, attr); - cpumask_and(sched_domain_span(sd), - cpumask_of_node(cpu_to_node(i)), cpu_map); + cpumask_and(sched_domain_span(sd), cpu_map, cpu_cpu_mask(i)); sd->parent = parent; if (parent) parent->child = sd; -- cgit v1.1 From eb7a74e6cd936c00749e2921b9e058631d986648 Mon Sep 17 00:00:00 2001 From: Peter Zijlstra Date: Thu, 7 Apr 2011 14:10:00 +0200 Subject: sched: Stuff the sched_domain creation in a data-structure In order to make the topology contruction fully dynamic, remove the still hard-coded list of possible domains and stick them in a data-structure. Signed-off-by: Peter Zijlstra Cc: Mike Galbraith Cc: Nick Piggin Cc: Linus Torvalds Cc: Andrew Morton Link: http://lkml.kernel.org/r/20110407122942.770335383@chello.nl Signed-off-by: Ingo Molnar --- kernel/sched.c | 32 ++++++++++++++++++++++++++------ 1 file changed, 26 insertions(+), 6 deletions(-) (limited to 'kernel') diff --git a/kernel/sched.c b/kernel/sched.c index 3ae1e02..f0e1821 100644 --- a/kernel/sched.c +++ b/kernel/sched.c @@ -6843,6 +6843,16 @@ enum s_alloc { sa_none, }; +typedef struct sched_domain *(*sched_domain_build_f)(struct s_data *d, + const struct cpumask *cpu_map, struct sched_domain_attr *attr, + struct sched_domain *parent, int cpu); + +typedef const struct cpumask *(*sched_domain_mask_f)(int cpu); + +struct sched_domain_topology_level { + sched_domain_build_f build; +}; + /* * Assumes the sched_domain tree is fully constructed */ @@ -7185,6 +7195,18 @@ static struct sched_domain *__build_smt_sched_domain(struct s_data *d, return sd; } +static struct sched_domain_topology_level default_topology[] = { + { __build_allnodes_sched_domain, }, + { __build_node_sched_domain, }, + { __build_cpu_sched_domain, }, + { __build_book_sched_domain, }, + { __build_mc_sched_domain, }, + { __build_smt_sched_domain, }, + { NULL, }, +}; + +static struct sched_domain_topology_level *sched_domain_topology = default_topology; + /* * Build sched domains for a given set of cpus and attach the sched domains * to the individual cpus @@ -7203,13 +7225,11 @@ static int build_sched_domains(const struct cpumask *cpu_map, /* Set up domains for cpus specified by the cpu_map. */ for_each_cpu(i, cpu_map) { + struct sched_domain_topology_level *tl; + sd = NULL; - sd = __build_allnodes_sched_domain(&d, cpu_map, attr, sd, i); - sd = __build_node_sched_domain(&d, cpu_map, attr, sd, i); - sd = __build_cpu_sched_domain(&d, cpu_map, attr, sd, i); - sd = __build_book_sched_domain(&d, cpu_map, attr, sd, i); - sd = __build_mc_sched_domain(&d, cpu_map, attr, sd, i); - sd = __build_smt_sched_domain(&d, cpu_map, attr, sd, i); + for (tl = sched_domain_topology; tl->build; tl++) + sd = tl->build(&d, cpu_map, attr, sd, i); *per_cpu_ptr(d.sd, i) = sd; } -- cgit v1.1 From 2c402dc3bb502e9dd74fce72c14d293fcef4719d Mon Sep 17 00:00:00 2001 From: Peter Zijlstra Date: Thu, 7 Apr 2011 14:10:01 +0200 Subject: sched: Unify the sched_domain build functions Since all the __build_$DOM_sched_domain() functions do pretty much the same thing, unify them. Signed-off-by: Peter Zijlstra Cc: Mike Galbraith Cc: Nick Piggin Cc: Linus Torvalds Cc: Andrew Morton Link: http://lkml.kernel.org/r/20110407122942.826347257@chello.nl Signed-off-by: Ingo Molnar --- kernel/sched.c | 133 +++++++++++++++++---------------------------------------- 1 file changed, 39 insertions(+), 94 deletions(-) (limited to 'kernel') diff --git a/kernel/sched.c b/kernel/sched.c index f0e1821..00d1e37 100644 --- a/kernel/sched.c +++ b/kernel/sched.c @@ -6816,6 +6816,11 @@ static const struct cpumask *cpu_node_mask(int cpu) return sched_domains_tmpmask; } + +static const struct cpumask *cpu_allnodes_mask(int cpu) +{ + return cpu_possible_mask; +} #endif /* CONFIG_NUMA */ static const struct cpumask *cpu_cpu_mask(int cpu) @@ -6843,14 +6848,12 @@ enum s_alloc { sa_none, }; -typedef struct sched_domain *(*sched_domain_build_f)(struct s_data *d, - const struct cpumask *cpu_map, struct sched_domain_attr *attr, - struct sched_domain *parent, int cpu); - +typedef struct sched_domain *(*sched_domain_init_f)(struct s_data *d, int cpu); typedef const struct cpumask *(*sched_domain_mask_f)(int cpu); struct sched_domain_topology_level { - sched_domain_build_f build; + sched_domain_init_f init; + sched_domain_mask_f mask; }; /* @@ -7104,109 +7107,51 @@ static void claim_allocations(int cpu, struct sched_domain *sd) } } -static struct sched_domain *__build_allnodes_sched_domain(struct s_data *d, - const struct cpumask *cpu_map, struct sched_domain_attr *attr, - struct sched_domain *parent, int i) +#ifdef CONFIG_SCHED_SMT +static const struct cpumask *cpu_smt_mask(int cpu) { - struct sched_domain *sd = NULL; -#ifdef CONFIG_NUMA - sd = sd_init_ALLNODES(d, i); - set_domain_attribute(sd, attr); - cpumask_and(sched_domain_span(sd), cpu_map, cpu_possible_mask); - sd->parent = parent; - if (parent) - parent->child = sd; -#endif - return sd; + return topology_thread_cpumask(cpu); } +#endif -static struct sched_domain *__build_node_sched_domain(struct s_data *d, - const struct cpumask *cpu_map, struct sched_domain_attr *attr, - struct sched_domain *parent, int i) -{ - struct sched_domain *sd = NULL; +static struct sched_domain_topology_level default_topology[] = { #ifdef CONFIG_NUMA - sd = sd_init_NODE(d, i); - set_domain_attribute(sd, attr); - cpumask_and(sched_domain_span(sd), cpu_map, cpu_node_mask(i)); - sd->parent = parent; - if (parent) - parent->child = sd; + { sd_init_ALLNODES, cpu_allnodes_mask, }, + { sd_init_NODE, cpu_node_mask, }, #endif - return sd; -} - -static struct sched_domain *__build_cpu_sched_domain(struct s_data *d, - const struct cpumask *cpu_map, struct sched_domain_attr *attr, - struct sched_domain *parent, int i) -{ - struct sched_domain *sd; - sd = sd_init_CPU(d, i); - set_domain_attribute(sd, attr); - cpumask_and(sched_domain_span(sd), cpu_map, cpu_cpu_mask(i)); - sd->parent = parent; - if (parent) - parent->child = sd; - return sd; -} - -static struct sched_domain *__build_book_sched_domain(struct s_data *d, - const struct cpumask *cpu_map, struct sched_domain_attr *attr, - struct sched_domain *parent, int i) -{ - struct sched_domain *sd = parent; + { sd_init_CPU, cpu_cpu_mask, }, #ifdef CONFIG_SCHED_BOOK - sd = sd_init_BOOK(d, i); - set_domain_attribute(sd, attr); - cpumask_and(sched_domain_span(sd), cpu_map, cpu_book_mask(i)); - sd->parent = parent; - parent->child = sd; + { sd_init_BOOK, cpu_book_mask, }, #endif - return sd; -} - -static struct sched_domain *__build_mc_sched_domain(struct s_data *d, - const struct cpumask *cpu_map, struct sched_domain_attr *attr, - struct sched_domain *parent, int i) -{ - struct sched_domain *sd = parent; #ifdef CONFIG_SCHED_MC - sd = sd_init_MC(d, i); - set_domain_attribute(sd, attr); - cpumask_and(sched_domain_span(sd), cpu_map, cpu_coregroup_mask(i)); - sd->parent = parent; - parent->child = sd; + { sd_init_MC, cpu_coregroup_mask, }, #endif - return sd; -} - -static struct sched_domain *__build_smt_sched_domain(struct s_data *d, - const struct cpumask *cpu_map, struct sched_domain_attr *attr, - struct sched_domain *parent, int i) -{ - struct sched_domain *sd = parent; #ifdef CONFIG_SCHED_SMT - sd = sd_init_SIBLING(d, i); - set_domain_attribute(sd, attr); - cpumask_and(sched_domain_span(sd), cpu_map, topology_thread_cpumask(i)); - sd->parent = parent; - parent->child = sd; + { sd_init_SIBLING, cpu_smt_mask, }, #endif - return sd; -} - -static struct sched_domain_topology_level default_topology[] = { - { __build_allnodes_sched_domain, }, - { __build_node_sched_domain, }, - { __build_cpu_sched_domain, }, - { __build_book_sched_domain, }, - { __build_mc_sched_domain, }, - { __build_smt_sched_domain, }, { NULL, }, }; static struct sched_domain_topology_level *sched_domain_topology = default_topology; +struct sched_domain *build_sched_domain(struct sched_domain_topology_level *tl, + struct s_data *d, const struct cpumask *cpu_map, + struct sched_domain_attr *attr, struct sched_domain *parent, + int cpu) +{ + struct sched_domain *sd = tl->init(d, cpu); + if (!sd) + return parent; + + set_domain_attribute(sd, attr); + cpumask_and(sched_domain_span(sd), cpu_map, tl->mask(cpu)); + sd->parent = parent; + if (parent) + parent->child = sd; + + return sd; +} + /* * Build sched domains for a given set of cpus and attach the sched domains * to the individual cpus @@ -7228,8 +7173,8 @@ static int build_sched_domains(const struct cpumask *cpu_map, struct sched_domain_topology_level *tl; sd = NULL; - for (tl = sched_domain_topology; tl->build; tl++) - sd = tl->build(&d, cpu_map, attr, sd, i); + for (tl = sched_domain_topology; tl->init; tl++) + sd = build_sched_domain(tl, &d, cpu_map, attr, sd, i); *per_cpu_ptr(d.sd, i) = sd; } -- cgit v1.1 From d069b916f7b50021d41d6ce498f86da32a7afaec Mon Sep 17 00:00:00 2001 From: Peter Zijlstra Date: Thu, 7 Apr 2011 14:10:02 +0200 Subject: sched: Reverse the topology list In order to get rid of static sched_domain::level assignments, reverse the topology iteration. Signed-off-by: Peter Zijlstra Cc: Mike Galbraith Cc: Nick Piggin Cc: Linus Torvalds Cc: Andrew Morton Link: http://lkml.kernel.org/r/20110407122942.876506131@chello.nl Signed-off-by: Ingo Molnar --- kernel/sched.c | 34 ++++++++++++++++++++-------------- 1 file changed, 20 insertions(+), 14 deletions(-) (limited to 'kernel') diff --git a/kernel/sched.c b/kernel/sched.c index 00d1e37..38bc53b 100644 --- a/kernel/sched.c +++ b/kernel/sched.c @@ -7114,20 +7114,23 @@ static const struct cpumask *cpu_smt_mask(int cpu) } #endif +/* + * Topology list, bottom-up. + */ static struct sched_domain_topology_level default_topology[] = { -#ifdef CONFIG_NUMA - { sd_init_ALLNODES, cpu_allnodes_mask, }, - { sd_init_NODE, cpu_node_mask, }, -#endif - { sd_init_CPU, cpu_cpu_mask, }, -#ifdef CONFIG_SCHED_BOOK - { sd_init_BOOK, cpu_book_mask, }, +#ifdef CONFIG_SCHED_SMT + { sd_init_SIBLING, cpu_smt_mask, }, #endif #ifdef CONFIG_SCHED_MC { sd_init_MC, cpu_coregroup_mask, }, #endif -#ifdef CONFIG_SCHED_SMT - { sd_init_SIBLING, cpu_smt_mask, }, +#ifdef CONFIG_SCHED_BOOK + { sd_init_BOOK, cpu_book_mask, }, +#endif + { sd_init_CPU, cpu_cpu_mask, }, +#ifdef CONFIG_NUMA + { sd_init_NODE, cpu_node_mask, }, + { sd_init_ALLNODES, cpu_allnodes_mask, }, #endif { NULL, }, }; @@ -7136,18 +7139,18 @@ static struct sched_domain_topology_level *sched_domain_topology = default_topol struct sched_domain *build_sched_domain(struct sched_domain_topology_level *tl, struct s_data *d, const struct cpumask *cpu_map, - struct sched_domain_attr *attr, struct sched_domain *parent, + struct sched_domain_attr *attr, struct sched_domain *child, int cpu) { struct sched_domain *sd = tl->init(d, cpu); if (!sd) - return parent; + return child; set_domain_attribute(sd, attr); cpumask_and(sched_domain_span(sd), cpu_map, tl->mask(cpu)); - sd->parent = parent; - if (parent) - parent->child = sd; + if (child) + child->parent = sd; + sd->child = child; return sd; } @@ -7176,6 +7179,9 @@ static int build_sched_domains(const struct cpumask *cpu_map, for (tl = sched_domain_topology; tl->init; tl++) sd = build_sched_domain(tl, &d, cpu_map, attr, sd, i); + while (sd->child) + sd = sd->child; + *per_cpu_ptr(d.sd, i) = sd; } -- cgit v1.1 From 54ab4ff4316eb329d2c1acc110fbc623d2966931 Mon Sep 17 00:00:00 2001 From: Peter Zijlstra Date: Thu, 7 Apr 2011 14:10:03 +0200 Subject: sched: Move sched domain storage into the topology list In order to remove the last dependency on the statid domain levels, move the sd_data storage into the topology structure. Signed-off-by: Peter Zijlstra Cc: Mike Galbraith Cc: Nick Piggin Cc: Linus Torvalds Cc: Andrew Morton Link: http://lkml.kernel.org/r/20110407122942.924926412@chello.nl Signed-off-by: Ingo Molnar --- kernel/sched.c | 129 ++++++++++++++++++++++++++++++++++----------------------- 1 file changed, 77 insertions(+), 52 deletions(-) (limited to 'kernel') diff --git a/kernel/sched.c b/kernel/sched.c index 38bc53b..3231e19 100644 --- a/kernel/sched.c +++ b/kernel/sched.c @@ -6837,7 +6837,6 @@ struct sd_data { struct s_data { struct sched_domain ** __percpu sd; - struct sd_data sdd[SD_LV_MAX]; struct root_domain *rd; }; @@ -6848,12 +6847,15 @@ enum s_alloc { sa_none, }; -typedef struct sched_domain *(*sched_domain_init_f)(struct s_data *d, int cpu); +struct sched_domain_topology_level; + +typedef struct sched_domain *(*sched_domain_init_f)(struct sched_domain_topology_level *tl, int cpu); typedef const struct cpumask *(*sched_domain_mask_f)(int cpu); struct sched_domain_topology_level { sched_domain_init_f init; sched_domain_mask_f mask; + struct sd_data data; }; /* @@ -6958,15 +6960,16 @@ static void init_sched_groups_power(int cpu, struct sched_domain *sd) # define SD_INIT_NAME(sd, type) do { } while (0) #endif -#define SD_INIT_FUNC(type) \ -static noinline struct sched_domain *sd_init_##type(struct s_data *d, int cpu) \ -{ \ - struct sched_domain *sd = *per_cpu_ptr(d->sdd[SD_LV_##type].sd, cpu); \ - *sd = SD_##type##_INIT; \ - sd->level = SD_LV_##type; \ - SD_INIT_NAME(sd, type); \ - sd->private = &d->sdd[SD_LV_##type]; \ - return sd; \ +#define SD_INIT_FUNC(type) \ +static noinline struct sched_domain * \ +sd_init_##type(struct sched_domain_topology_level *tl, int cpu) \ +{ \ + struct sched_domain *sd = *per_cpu_ptr(tl->data.sd, cpu); \ + *sd = SD_##type##_INIT; \ + sd->level = SD_LV_##type; \ + SD_INIT_NAME(sd, type); \ + sd->private = &tl->data; \ + return sd; \ } SD_INIT_FUNC(CPU) @@ -7019,11 +7022,12 @@ static void set_domain_attribute(struct sched_domain *sd, } } +static void __sdt_free(const struct cpumask *cpu_map); +static int __sdt_alloc(const struct cpumask *cpu_map); + static void __free_domain_allocs(struct s_data *d, enum s_alloc what, const struct cpumask *cpu_map) { - int i, j; - switch (what) { case sa_rootdomain: if (!atomic_read(&d->rd->refcount)) @@ -7031,14 +7035,7 @@ static void __free_domain_allocs(struct s_data *d, enum s_alloc what, case sa_sd: free_percpu(d->sd); /* fall through */ case sa_sd_storage: - for (i = 0; i < SD_LV_MAX; i++) { - for_each_cpu(j, cpu_map) { - kfree(*per_cpu_ptr(d->sdd[i].sd, j)); - kfree(*per_cpu_ptr(d->sdd[i].sg, j)); - } - free_percpu(d->sdd[i].sd); - free_percpu(d->sdd[i].sg); - } /* fall through */ + __sdt_free(cpu_map); /* fall through */ case sa_none: break; } @@ -7047,38 +7044,10 @@ static void __free_domain_allocs(struct s_data *d, enum s_alloc what, static enum s_alloc __visit_domain_allocation_hell(struct s_data *d, const struct cpumask *cpu_map) { - int i, j; - memset(d, 0, sizeof(*d)); - for (i = 0; i < SD_LV_MAX; i++) { - d->sdd[i].sd = alloc_percpu(struct sched_domain *); - if (!d->sdd[i].sd) - return sa_sd_storage; - - d->sdd[i].sg = alloc_percpu(struct sched_group *); - if (!d->sdd[i].sg) - return sa_sd_storage; - - for_each_cpu(j, cpu_map) { - struct sched_domain *sd; - struct sched_group *sg; - - sd = kzalloc_node(sizeof(struct sched_domain) + cpumask_size(), - GFP_KERNEL, cpu_to_node(j)); - if (!sd) - return sa_sd_storage; - - *per_cpu_ptr(d->sdd[i].sd, j) = sd; - - sg = kzalloc_node(sizeof(struct sched_group) + cpumask_size(), - GFP_KERNEL, cpu_to_node(j)); - if (!sg) - return sa_sd_storage; - - *per_cpu_ptr(d->sdd[i].sg, j) = sg; - } - } + if (__sdt_alloc(cpu_map)) + return sa_sd_storage; d->sd = alloc_percpu(struct sched_domain *); if (!d->sd) return sa_sd_storage; @@ -7137,12 +7106,68 @@ static struct sched_domain_topology_level default_topology[] = { static struct sched_domain_topology_level *sched_domain_topology = default_topology; +static int __sdt_alloc(const struct cpumask *cpu_map) +{ + struct sched_domain_topology_level *tl; + int j; + + for (tl = sched_domain_topology; tl->init; tl++) { + struct sd_data *sdd = &tl->data; + + sdd->sd = alloc_percpu(struct sched_domain *); + if (!sdd->sd) + return -ENOMEM; + + sdd->sg = alloc_percpu(struct sched_group *); + if (!sdd->sg) + return -ENOMEM; + + for_each_cpu(j, cpu_map) { + struct sched_domain *sd; + struct sched_group *sg; + + sd = kzalloc_node(sizeof(struct sched_domain) + cpumask_size(), + GFP_KERNEL, cpu_to_node(j)); + if (!sd) + return -ENOMEM; + + *per_cpu_ptr(sdd->sd, j) = sd; + + sg = kzalloc_node(sizeof(struct sched_group) + cpumask_size(), + GFP_KERNEL, cpu_to_node(j)); + if (!sg) + return -ENOMEM; + + *per_cpu_ptr(sdd->sg, j) = sg; + } + } + + return 0; +} + +static void __sdt_free(const struct cpumask *cpu_map) +{ + struct sched_domain_topology_level *tl; + int j; + + for (tl = sched_domain_topology; tl->init; tl++) { + struct sd_data *sdd = &tl->data; + + for_each_cpu(j, cpu_map) { + kfree(*per_cpu_ptr(sdd->sd, j)); + kfree(*per_cpu_ptr(sdd->sg, j)); + } + free_percpu(sdd->sd); + free_percpu(sdd->sg); + } +} + struct sched_domain *build_sched_domain(struct sched_domain_topology_level *tl, struct s_data *d, const struct cpumask *cpu_map, struct sched_domain_attr *attr, struct sched_domain *child, int cpu) { - struct sched_domain *sd = tl->init(d, cpu); + struct sched_domain *sd = tl->init(tl, cpu); if (!sd) return child; -- cgit v1.1 From 60495e7760d8ee364695006af37309b0755e0e17 Mon Sep 17 00:00:00 2001 From: Peter Zijlstra Date: Thu, 7 Apr 2011 14:10:04 +0200 Subject: sched: Dynamic sched_domain::level Remove the SD_LV_ enum and use dynamic level assignments. Signed-off-by: Peter Zijlstra Cc: Mike Galbraith Cc: Nick Piggin Cc: Linus Torvalds Cc: Andrew Morton Link: http://lkml.kernel.org/r/20110407122942.969433965@chello.nl Signed-off-by: Ingo Molnar --- kernel/cpuset.c | 2 +- kernel/sched.c | 9 ++++++--- 2 files changed, 7 insertions(+), 4 deletions(-) (limited to 'kernel') diff --git a/kernel/cpuset.c b/kernel/cpuset.c index 33eee16..2bb8c2e 100644 --- a/kernel/cpuset.c +++ b/kernel/cpuset.c @@ -1159,7 +1159,7 @@ int current_cpuset_is_being_rebound(void) static int update_relax_domain_level(struct cpuset *cs, s64 val) { #ifdef CONFIG_SMP - if (val < -1 || val >= SD_LV_MAX) + if (val < -1 || val >= sched_domain_level_max) return -EINVAL; #endif diff --git a/kernel/sched.c b/kernel/sched.c index 3231e19..506cb81 100644 --- a/kernel/sched.c +++ b/kernel/sched.c @@ -6966,7 +6966,6 @@ sd_init_##type(struct sched_domain_topology_level *tl, int cpu) \ { \ struct sched_domain *sd = *per_cpu_ptr(tl->data.sd, cpu); \ *sd = SD_##type##_INIT; \ - sd->level = SD_LV_##type; \ SD_INIT_NAME(sd, type); \ sd->private = &tl->data; \ return sd; \ @@ -6988,13 +6987,14 @@ SD_INIT_FUNC(CPU) #endif static int default_relax_domain_level = -1; +int sched_domain_level_max; static int __init setup_relax_domain_level(char *str) { unsigned long val; val = simple_strtoul(str, NULL, 0); - if (val < SD_LV_MAX) + if (val < sched_domain_level_max) default_relax_domain_level = val; return 1; @@ -7173,8 +7173,11 @@ struct sched_domain *build_sched_domain(struct sched_domain_topology_level *tl, set_domain_attribute(sd, attr); cpumask_and(sched_domain_span(sd), cpu_map, tl->mask(cpu)); - if (child) + if (child) { + sd->level = child->level + 1; + sched_domain_level_max = max(sched_domain_level_max, sd->level); child->parent = sd; + } sd->child = child; return sd; -- cgit v1.1 From 3ca7a440da394808571dad32d33d3bc0389982e6 Mon Sep 17 00:00:00 2001 From: Peter Zijlstra Date: Tue, 5 Apr 2011 17:23:40 +0200 Subject: sched: Always provide p->on_cpu Always provide p->on_cpu so that we can determine if its on a cpu without having to lock the rq. Reviewed-by: Frank Rowand Signed-off-by: Peter Zijlstra Cc: Mike Galbraith Cc: Nick Piggin Cc: Linus Torvalds Cc: Andrew Morton Link: http://lkml.kernel.org/r/20110405152728.785452014@chello.nl Signed-off-by: Ingo Molnar --- kernel/sched.c | 46 +++++++++++++++++++++++++++++----------------- 1 file changed, 29 insertions(+), 17 deletions(-) (limited to 'kernel') diff --git a/kernel/sched.c b/kernel/sched.c index a187c3f..cd2593e 100644 --- a/kernel/sched.c +++ b/kernel/sched.c @@ -838,18 +838,39 @@ static inline int task_current(struct rq *rq, struct task_struct *p) return rq->curr == p; } -#ifndef __ARCH_WANT_UNLOCKED_CTXSW static inline int task_running(struct rq *rq, struct task_struct *p) { +#ifdef CONFIG_SMP + return p->on_cpu; +#else return task_current(rq, p); +#endif } +#ifndef __ARCH_WANT_UNLOCKED_CTXSW static inline void prepare_lock_switch(struct rq *rq, struct task_struct *next) { +#ifdef CONFIG_SMP + /* + * We can optimise this out completely for !SMP, because the + * SMP rebalancing from interrupt is the only thing that cares + * here. + */ + next->on_cpu = 1; +#endif } static inline void finish_lock_switch(struct rq *rq, struct task_struct *prev) { +#ifdef CONFIG_SMP + /* + * After ->on_cpu is cleared, the task can be moved to a different CPU. + * We must ensure this doesn't happen until the switch is completely + * finished. + */ + smp_wmb(); + prev->on_cpu = 0; +#endif #ifdef CONFIG_DEBUG_SPINLOCK /* this is a valid case when another task releases the spinlock */ rq->lock.owner = current; @@ -865,15 +886,6 @@ static inline void finish_lock_switch(struct rq *rq, struct task_struct *prev) } #else /* __ARCH_WANT_UNLOCKED_CTXSW */ -static inline int task_running(struct rq *rq, struct task_struct *p) -{ -#ifdef CONFIG_SMP - return p->oncpu; -#else - return task_current(rq, p); -#endif -} - static inline void prepare_lock_switch(struct rq *rq, struct task_struct *next) { #ifdef CONFIG_SMP @@ -882,7 +894,7 @@ static inline void prepare_lock_switch(struct rq *rq, struct task_struct *next) * SMP rebalancing from interrupt is the only thing that cares * here. */ - next->oncpu = 1; + next->on_cpu = 1; #endif #ifdef __ARCH_WANT_INTERRUPTS_ON_CTXSW raw_spin_unlock_irq(&rq->lock); @@ -895,12 +907,12 @@ static inline void finish_lock_switch(struct rq *rq, struct task_struct *prev) { #ifdef CONFIG_SMP /* - * After ->oncpu is cleared, the task can be moved to a different CPU. + * After ->on_cpu is cleared, the task can be moved to a different CPU. * We must ensure this doesn't happen until the switch is completely * finished. */ smp_wmb(); - prev->oncpu = 0; + prev->on_cpu = 0; #endif #ifndef __ARCH_WANT_INTERRUPTS_ON_CTXSW local_irq_enable(); @@ -2686,8 +2698,8 @@ void sched_fork(struct task_struct *p, int clone_flags) if (likely(sched_info_on())) memset(&p->sched_info, 0, sizeof(p->sched_info)); #endif -#if defined(CONFIG_SMP) && defined(__ARCH_WANT_UNLOCKED_CTXSW) - p->oncpu = 0; +#if defined(CONFIG_SMP) + p->on_cpu = 0; #endif #ifdef CONFIG_PREEMPT /* Want to start with kernel preemption disabled. */ @@ -5776,8 +5788,8 @@ void __cpuinit init_idle(struct task_struct *idle, int cpu) rcu_read_unlock(); rq->curr = rq->idle = idle; -#if defined(CONFIG_SMP) && defined(__ARCH_WANT_UNLOCKED_CTXSW) - idle->oncpu = 1; +#if defined(CONFIG_SMP) + idle->on_cpu = 1; #endif raw_spin_unlock_irqrestore(&rq->lock, flags); -- cgit v1.1 From c6eb3dda25892f1f974f5420f63e6721aab02f6f Mon Sep 17 00:00:00 2001 From: Peter Zijlstra Date: Tue, 5 Apr 2011 17:23:41 +0200 Subject: mutex: Use p->on_cpu for the adaptive spin Since we now have p->on_cpu unconditionally available, use it to re-implement mutex_spin_on_owner. Requested-by: Thomas Gleixner Reviewed-by: Frank Rowand Cc: Mike Galbraith Cc: Nick Piggin Cc: Linus Torvalds Cc: Andrew Morton Signed-off-by: Ingo Molnar Signed-off-by: Peter Zijlstra Link: http://lkml.kernel.org/r/20110405152728.826338173@chello.nl --- kernel/mutex-debug.c | 2 +- kernel/mutex-debug.h | 2 +- kernel/mutex.c | 2 +- kernel/mutex.h | 2 +- kernel/sched.c | 83 +++++++++++++++++++++------------------------------- 5 files changed, 37 insertions(+), 54 deletions(-) (limited to 'kernel') diff --git a/kernel/mutex-debug.c b/kernel/mutex-debug.c index ec815a9..73da83a 100644 --- a/kernel/mutex-debug.c +++ b/kernel/mutex-debug.c @@ -75,7 +75,7 @@ void debug_mutex_unlock(struct mutex *lock) return; DEBUG_LOCKS_WARN_ON(lock->magic != lock); - DEBUG_LOCKS_WARN_ON(lock->owner != current_thread_info()); + DEBUG_LOCKS_WARN_ON(lock->owner != current); DEBUG_LOCKS_WARN_ON(!lock->wait_list.prev && !lock->wait_list.next); mutex_clear_owner(lock); } diff --git a/kernel/mutex-debug.h b/kernel/mutex-debug.h index 57d527a..0799fd3 100644 --- a/kernel/mutex-debug.h +++ b/kernel/mutex-debug.h @@ -29,7 +29,7 @@ extern void debug_mutex_init(struct mutex *lock, const char *name, static inline void mutex_set_owner(struct mutex *lock) { - lock->owner = current_thread_info(); + lock->owner = current; } static inline void mutex_clear_owner(struct mutex *lock) diff --git a/kernel/mutex.c b/kernel/mutex.c index c4195fa..fe4706c 100644 --- a/kernel/mutex.c +++ b/kernel/mutex.c @@ -160,7 +160,7 @@ __mutex_lock_common(struct mutex *lock, long state, unsigned int subclass, */ for (;;) { - struct thread_info *owner; + struct task_struct *owner; /* * If we own the BKL, then don't spin. The owner of diff --git a/kernel/mutex.h b/kernel/mutex.h index 67578ca..4115fbf 100644 --- a/kernel/mutex.h +++ b/kernel/mutex.h @@ -19,7 +19,7 @@ #ifdef CONFIG_SMP static inline void mutex_set_owner(struct mutex *lock) { - lock->owner = current_thread_info(); + lock->owner = current; } static inline void mutex_clear_owner(struct mutex *lock) diff --git a/kernel/sched.c b/kernel/sched.c index cd2593e..55cc503 100644 --- a/kernel/sched.c +++ b/kernel/sched.c @@ -4173,70 +4173,53 @@ need_resched: EXPORT_SYMBOL(schedule); #ifdef CONFIG_MUTEX_SPIN_ON_OWNER -/* - * Look out! "owner" is an entirely speculative pointer - * access and not reliable. - */ -int mutex_spin_on_owner(struct mutex *lock, struct thread_info *owner) -{ - unsigned int cpu; - struct rq *rq; - if (!sched_feat(OWNER_SPIN)) - return 0; +static inline bool owner_running(struct mutex *lock, struct task_struct *owner) +{ + bool ret = false; -#ifdef CONFIG_DEBUG_PAGEALLOC - /* - * Need to access the cpu field knowing that - * DEBUG_PAGEALLOC could have unmapped it if - * the mutex owner just released it and exited. - */ - if (probe_kernel_address(&owner->cpu, cpu)) - return 0; -#else - cpu = owner->cpu; -#endif + rcu_read_lock(); + if (lock->owner != owner) + goto fail; /* - * Even if the access succeeded (likely case), - * the cpu field may no longer be valid. + * Ensure we emit the owner->on_cpu, dereference _after_ checking + * lock->owner still matches owner, if that fails, owner might + * point to free()d memory, if it still matches, the rcu_read_lock() + * ensures the memory stays valid. */ - if (cpu >= nr_cpumask_bits) - return 0; + barrier(); - /* - * We need to validate that we can do a - * get_cpu() and that we have the percpu area. - */ - if (!cpu_online(cpu)) - return 0; + ret = owner->on_cpu; +fail: + rcu_read_unlock(); - rq = cpu_rq(cpu); + return ret; +} - for (;;) { - /* - * Owner changed, break to re-assess state. - */ - if (lock->owner != owner) { - /* - * If the lock has switched to a different owner, - * we likely have heavy contention. Return 0 to quit - * optimistic spinning and not contend further: - */ - if (lock->owner) - return 0; - break; - } +/* + * Look out! "owner" is an entirely speculative pointer + * access and not reliable. + */ +int mutex_spin_on_owner(struct mutex *lock, struct task_struct *owner) +{ + if (!sched_feat(OWNER_SPIN)) + return 0; - /* - * Is that owner really running on that cpu? - */ - if (task_thread_info(rq->curr) != owner || need_resched()) + while (owner_running(lock, owner)) { + if (need_resched()) return 0; arch_mutex_cpu_relax(); } + /* + * If the owner changed to another task there is likely + * heavy contention, stop spinning. + */ + if (lock->owner) + return 0; + return 1; } #endif -- cgit v1.1 From c2f7115e2e52a6c187b8c1f54f0e4970bb677be0 Mon Sep 17 00:00:00 2001 From: Peter Zijlstra Date: Wed, 13 Apr 2011 13:28:56 +0200 Subject: sched: Move wq_worker_waking to the correct site wq_worker_waking_up() needs to match wq_worker_sleeping(), since the latter is only called on deactivate, move the former near activate. Signed-off-by: Peter Zijlstra Cc: Tejun Heo Link: http://lkml.kernel.org/n/top-t3m7n70n9frmv4pv2n5fwmov@git.kernel.org Signed-off-by: Ingo Molnar --- kernel/sched.c | 7 ++++--- 1 file changed, 4 insertions(+), 3 deletions(-) (limited to 'kernel') diff --git a/kernel/sched.c b/kernel/sched.c index 55cc503..81ab58e 100644 --- a/kernel/sched.c +++ b/kernel/sched.c @@ -2421,6 +2421,10 @@ static inline void ttwu_activate(struct task_struct *p, struct rq *rq, schedstat_inc(p, se.statistics.nr_wakeups_remote); activate_task(rq, p, en_flags); + + /* if a worker is waking up, notify workqueue */ + if (p->flags & PF_WQ_WORKER) + wq_worker_waking_up(p, cpu_of(rq)); } static inline void ttwu_post_activation(struct task_struct *p, struct rq *rq, @@ -2445,9 +2449,6 @@ static inline void ttwu_post_activation(struct task_struct *p, struct rq *rq, rq->idle_stamp = 0; } #endif - /* if a worker is waking up, notify workqueue */ - if ((p->flags & PF_WQ_WORKER) && success) - wq_worker_waking_up(p, cpu_of(rq)); } /** -- cgit v1.1 From 893633817f5b58f5227365d74344e0170a718213 Mon Sep 17 00:00:00 2001 From: Peter Zijlstra Date: Tue, 5 Apr 2011 17:23:42 +0200 Subject: sched: Change the ttwu() success details try_to_wake_up() would only return a success when it would have to place a task on a rq, change that to every time we change p->state to TASK_RUNNING, because that's the real measure of wakeups. This results in that success is always true for the tracepoints. Reviewed-by: Frank Rowand Cc: Mike Galbraith Cc: Nick Piggin Cc: Linus Torvalds Cc: Andrew Morton Signed-off-by: Ingo Molnar Signed-off-by: Peter Zijlstra Link: http://lkml.kernel.org/r/20110405152728.866866929@chello.nl --- kernel/sched.c | 16 +++++++--------- 1 file changed, 7 insertions(+), 9 deletions(-) (limited to 'kernel') diff --git a/kernel/sched.c b/kernel/sched.c index 81ab58e..3919aa4 100644 --- a/kernel/sched.c +++ b/kernel/sched.c @@ -2427,10 +2427,10 @@ static inline void ttwu_activate(struct task_struct *p, struct rq *rq, wq_worker_waking_up(p, cpu_of(rq)); } -static inline void ttwu_post_activation(struct task_struct *p, struct rq *rq, - int wake_flags, bool success) +static void +ttwu_post_activation(struct task_struct *p, struct rq *rq, int wake_flags) { - trace_sched_wakeup(p, success); + trace_sched_wakeup(p, true); check_preempt_curr(rq, p, wake_flags); p->state = TASK_RUNNING; @@ -2546,9 +2546,9 @@ out_activate: #endif /* CONFIG_SMP */ ttwu_activate(p, rq, wake_flags & WF_SYNC, orig_cpu != cpu, cpu == this_cpu, en_flags); - success = 1; out_running: - ttwu_post_activation(p, rq, wake_flags, success); + ttwu_post_activation(p, rq, wake_flags); + success = 1; out: task_rq_unlock(rq, &flags); put_cpu(); @@ -2567,7 +2567,6 @@ out: static void try_to_wake_up_local(struct task_struct *p) { struct rq *rq = task_rq(p); - bool success = false; BUG_ON(rq != this_rq()); BUG_ON(p == current); @@ -2582,9 +2581,8 @@ static void try_to_wake_up_local(struct task_struct *p) schedstat_inc(rq, ttwu_local); } ttwu_activate(p, rq, false, false, true, ENQUEUE_WAKEUP); - success = true; } - ttwu_post_activation(p, rq, 0, success); + ttwu_post_activation(p, rq, 0); } /** @@ -2747,7 +2745,7 @@ void wake_up_new_task(struct task_struct *p, unsigned long clone_flags) rq = task_rq_lock(p, &flags); activate_task(rq, p, 0); - trace_sched_wakeup_new(p, 1); + trace_sched_wakeup_new(p, true); check_preempt_curr(rq, p, WF_FORK); #ifdef CONFIG_SMP if (p->sched_class->task_woken) -- cgit v1.1 From d7c01d27ab767a30d672d1fd657aa8336ebdcbca Mon Sep 17 00:00:00 2001 From: Peter Zijlstra Date: Tue, 5 Apr 2011 17:23:43 +0200 Subject: sched: Clean up ttwu() stats Collect all ttwu() stat code into a single function and ensure its always called for an actual wakeup (changing p->state to TASK_RUNNING). Reviewed-by: Frank Rowand Cc: Mike Galbraith Cc: Nick Piggin Cc: Linus Torvalds Cc: Andrew Morton Signed-off-by: Ingo Molnar Signed-off-by: Peter Zijlstra Link: http://lkml.kernel.org/r/20110405152728.908177058@chello.nl --- kernel/sched.c | 75 +++++++++++++++++++++++++++++++--------------------------- 1 file changed, 40 insertions(+), 35 deletions(-) (limited to 'kernel') diff --git a/kernel/sched.c b/kernel/sched.c index 3919aa4..4481638 100644 --- a/kernel/sched.c +++ b/kernel/sched.c @@ -2406,20 +2406,43 @@ static void update_avg(u64 *avg, u64 sample) } #endif -static inline void ttwu_activate(struct task_struct *p, struct rq *rq, - bool is_sync, bool is_migrate, bool is_local, - unsigned long en_flags) +static void +ttwu_stat(struct rq *rq, struct task_struct *p, int cpu, int wake_flags) { +#ifdef CONFIG_SCHEDSTATS +#ifdef CONFIG_SMP + int this_cpu = smp_processor_id(); + + if (cpu == this_cpu) { + schedstat_inc(rq, ttwu_local); + schedstat_inc(p, se.statistics.nr_wakeups_local); + } else { + struct sched_domain *sd; + + schedstat_inc(p, se.statistics.nr_wakeups_remote); + for_each_domain(this_cpu, sd) { + if (cpumask_test_cpu(cpu, sched_domain_span(sd))) { + schedstat_inc(sd, ttwu_wake_remote); + break; + } + } + } +#endif /* CONFIG_SMP */ + + schedstat_inc(rq, ttwu_count); schedstat_inc(p, se.statistics.nr_wakeups); - if (is_sync) + + if (wake_flags & WF_SYNC) schedstat_inc(p, se.statistics.nr_wakeups_sync); - if (is_migrate) + + if (cpu != task_cpu(p)) schedstat_inc(p, se.statistics.nr_wakeups_migrate); - if (is_local) - schedstat_inc(p, se.statistics.nr_wakeups_local); - else - schedstat_inc(p, se.statistics.nr_wakeups_remote); +#endif /* CONFIG_SCHEDSTATS */ +} + +static void ttwu_activate(struct rq *rq, struct task_struct *p, int en_flags) +{ activate_task(rq, p, en_flags); /* if a worker is waking up, notify workqueue */ @@ -2481,12 +2504,12 @@ static int try_to_wake_up(struct task_struct *p, unsigned int state, if (!(p->state & state)) goto out; + cpu = task_cpu(p); + if (p->se.on_rq) goto out_running; - cpu = task_cpu(p); orig_cpu = cpu; - #ifdef CONFIG_SMP if (unlikely(task_running(rq, p))) goto out_activate; @@ -2527,27 +2550,12 @@ static int try_to_wake_up(struct task_struct *p, unsigned int state, WARN_ON(task_cpu(p) != cpu); WARN_ON(p->state != TASK_WAKING); -#ifdef CONFIG_SCHEDSTATS - schedstat_inc(rq, ttwu_count); - if (cpu == this_cpu) - schedstat_inc(rq, ttwu_local); - else { - struct sched_domain *sd; - for_each_domain(this_cpu, sd) { - if (cpumask_test_cpu(cpu, sched_domain_span(sd))) { - schedstat_inc(sd, ttwu_wake_remote); - break; - } - } - } -#endif /* CONFIG_SCHEDSTATS */ - out_activate: #endif /* CONFIG_SMP */ - ttwu_activate(p, rq, wake_flags & WF_SYNC, orig_cpu != cpu, - cpu == this_cpu, en_flags); + ttwu_activate(rq, p, en_flags); out_running: ttwu_post_activation(p, rq, wake_flags); + ttwu_stat(rq, p, cpu, wake_flags); success = 1; out: task_rq_unlock(rq, &flags); @@ -2575,14 +2583,11 @@ static void try_to_wake_up_local(struct task_struct *p) if (!(p->state & TASK_NORMAL)) return; - if (!p->se.on_rq) { - if (likely(!task_running(rq, p))) { - schedstat_inc(rq, ttwu_count); - schedstat_inc(rq, ttwu_local); - } - ttwu_activate(p, rq, false, false, true, ENQUEUE_WAKEUP); - } + if (!p->se.on_rq) + ttwu_activate(rq, p, ENQUEUE_WAKEUP); + ttwu_post_activation(p, rq, 0); + ttwu_stat(rq, p, smp_processor_id(), 0); } /** -- cgit v1.1 From fd2f4419b4cbe8fe90796df9617c355762afd6a4 Mon Sep 17 00:00:00 2001 From: Peter Zijlstra Date: Tue, 5 Apr 2011 17:23:44 +0200 Subject: sched: Provide p->on_rq Provide a generic p->on_rq because the p->se.on_rq semantics are unfavourable for lockless wakeups but needed for sched_fair. In particular, p->on_rq is only cleared when we actually dequeue the task in schedule() and not on any random dequeue as done by things like __migrate_task() and __sched_setscheduler(). This also allows us to remove p->se usage from !sched_fair code. Reviewed-by: Frank Rowand Cc: Mike Galbraith Cc: Nick Piggin Cc: Linus Torvalds Cc: Andrew Morton Signed-off-by: Ingo Molnar Signed-off-by: Peter Zijlstra Link: http://lkml.kernel.org/r/20110405152728.949545047@chello.nl --- kernel/sched.c | 38 ++++++++++++++++++++------------------ kernel/sched_debug.c | 2 +- kernel/sched_rt.c | 16 ++++++++-------- kernel/sched_stoptask.c | 2 +- 4 files changed, 30 insertions(+), 28 deletions(-) (limited to 'kernel') diff --git a/kernel/sched.c b/kernel/sched.c index 4481638..dece28e 100644 --- a/kernel/sched.c +++ b/kernel/sched.c @@ -1785,7 +1785,6 @@ static void enqueue_task(struct rq *rq, struct task_struct *p, int flags) update_rq_clock(rq); sched_info_queued(p); p->sched_class->enqueue_task(rq, p, flags); - p->se.on_rq = 1; } static void dequeue_task(struct rq *rq, struct task_struct *p, int flags) @@ -1793,7 +1792,6 @@ static void dequeue_task(struct rq *rq, struct task_struct *p, int flags) update_rq_clock(rq); sched_info_dequeued(p); p->sched_class->dequeue_task(rq, p, flags); - p->se.on_rq = 0; } /* @@ -2128,7 +2126,7 @@ static void check_preempt_curr(struct rq *rq, struct task_struct *p, int flags) * A queue event has occurred, and we're going to schedule. In * this case, we can save a useless back to back clock update. */ - if (rq->curr->se.on_rq && test_tsk_need_resched(rq->curr)) + if (rq->curr->on_rq && test_tsk_need_resched(rq->curr)) rq->skip_clock_update = 1; } @@ -2203,7 +2201,7 @@ static bool migrate_task(struct task_struct *p, struct rq *rq) * If the task is not on a runqueue (and not running), then * the next wake-up will properly place the task. */ - return p->se.on_rq || task_running(rq, p); + return p->on_rq || task_running(rq, p); } /* @@ -2263,7 +2261,7 @@ unsigned long wait_task_inactive(struct task_struct *p, long match_state) rq = task_rq_lock(p, &flags); trace_sched_wait_task(p); running = task_running(rq, p); - on_rq = p->se.on_rq; + on_rq = p->on_rq; ncsw = 0; if (!match_state || p->state == match_state) ncsw = p->nvcsw | LONG_MIN; /* sets MSB */ @@ -2444,6 +2442,7 @@ ttwu_stat(struct rq *rq, struct task_struct *p, int cpu, int wake_flags) static void ttwu_activate(struct rq *rq, struct task_struct *p, int en_flags) { activate_task(rq, p, en_flags); + p->on_rq = 1; /* if a worker is waking up, notify workqueue */ if (p->flags & PF_WQ_WORKER) @@ -2506,7 +2505,7 @@ static int try_to_wake_up(struct task_struct *p, unsigned int state, cpu = task_cpu(p); - if (p->se.on_rq) + if (p->on_rq) goto out_running; orig_cpu = cpu; @@ -2583,7 +2582,7 @@ static void try_to_wake_up_local(struct task_struct *p) if (!(p->state & TASK_NORMAL)) return; - if (!p->se.on_rq) + if (!p->on_rq) ttwu_activate(rq, p, ENQUEUE_WAKEUP); ttwu_post_activation(p, rq, 0); @@ -2620,19 +2619,21 @@ int wake_up_state(struct task_struct *p, unsigned int state) */ static void __sched_fork(struct task_struct *p) { + p->on_rq = 0; + + p->se.on_rq = 0; p->se.exec_start = 0; p->se.sum_exec_runtime = 0; p->se.prev_sum_exec_runtime = 0; p->se.nr_migrations = 0; p->se.vruntime = 0; + INIT_LIST_HEAD(&p->se.group_node); #ifdef CONFIG_SCHEDSTATS memset(&p->se.statistics, 0, sizeof(p->se.statistics)); #endif INIT_LIST_HEAD(&p->rt.run_list); - p->se.on_rq = 0; - INIT_LIST_HEAD(&p->se.group_node); #ifdef CONFIG_PREEMPT_NOTIFIERS INIT_HLIST_HEAD(&p->preempt_notifiers); @@ -2750,6 +2751,7 @@ void wake_up_new_task(struct task_struct *p, unsigned long clone_flags) rq = task_rq_lock(p, &flags); activate_task(rq, p, 0); + p->on_rq = 1; trace_sched_wakeup_new(p, true); check_preempt_curr(rq, p, WF_FORK); #ifdef CONFIG_SMP @@ -4051,7 +4053,7 @@ static inline void schedule_debug(struct task_struct *prev) static void put_prev_task(struct rq *rq, struct task_struct *prev) { - if (prev->se.on_rq) + if (prev->on_rq) update_rq_clock(rq); prev->sched_class->put_prev_task(rq, prev); } @@ -4126,7 +4128,9 @@ need_resched: if (to_wakeup) try_to_wake_up_local(to_wakeup); } + deactivate_task(rq, prev, DEQUEUE_SLEEP); + prev->on_rq = 0; /* * If we are going to sleep and we have plugged IO queued, make @@ -4695,7 +4699,7 @@ void rt_mutex_setprio(struct task_struct *p, int prio) trace_sched_pi_setprio(p, prio); oldprio = p->prio; prev_class = p->sched_class; - on_rq = p->se.on_rq; + on_rq = p->on_rq; running = task_current(rq, p); if (on_rq) dequeue_task(rq, p, 0); @@ -4743,7 +4747,7 @@ void set_user_nice(struct task_struct *p, long nice) p->static_prio = NICE_TO_PRIO(nice); goto out_unlock; } - on_rq = p->se.on_rq; + on_rq = p->on_rq; if (on_rq) dequeue_task(rq, p, 0); @@ -4877,8 +4881,6 @@ static struct task_struct *find_process_by_pid(pid_t pid) static void __setscheduler(struct rq *rq, struct task_struct *p, int policy, int prio) { - BUG_ON(p->se.on_rq); - p->policy = policy; p->rt_priority = prio; p->normal_prio = normal_prio(p); @@ -5044,7 +5046,7 @@ recheck: raw_spin_unlock_irqrestore(&p->pi_lock, flags); goto recheck; } - on_rq = p->se.on_rq; + on_rq = p->on_rq; running = task_current(rq, p); if (on_rq) deactivate_task(rq, p, 0); @@ -5965,7 +5967,7 @@ static int __migrate_task(struct task_struct *p, int src_cpu, int dest_cpu) * If we're not on a rq, the next wake-up will ensure we're * placed properly. */ - if (p->se.on_rq) { + if (p->on_rq) { deactivate_task(rq_src, p, 0); set_task_cpu(p, dest_cpu); activate_task(rq_dest, p, 0); @@ -8339,7 +8341,7 @@ static void normalize_task(struct rq *rq, struct task_struct *p) int old_prio = p->prio; int on_rq; - on_rq = p->se.on_rq; + on_rq = p->on_rq; if (on_rq) deactivate_task(rq, p, 0); __setscheduler(rq, p, SCHED_NORMAL, 0); @@ -8682,7 +8684,7 @@ void sched_move_task(struct task_struct *tsk) rq = task_rq_lock(tsk, &flags); running = task_current(rq, tsk); - on_rq = tsk->se.on_rq; + on_rq = tsk->on_rq; if (on_rq) dequeue_task(rq, tsk, 0); diff --git a/kernel/sched_debug.c b/kernel/sched_debug.c index 7bacd83..3669bec6 100644 --- a/kernel/sched_debug.c +++ b/kernel/sched_debug.c @@ -152,7 +152,7 @@ static void print_rq(struct seq_file *m, struct rq *rq, int rq_cpu) read_lock_irqsave(&tasklist_lock, flags); do_each_thread(g, p) { - if (!p->se.on_rq || task_cpu(p) != rq_cpu) + if (!p->on_rq || task_cpu(p) != rq_cpu) continue; print_task(m, rq, p); diff --git a/kernel/sched_rt.c b/kernel/sched_rt.c index e7cebdc..9ca4f5f 100644 --- a/kernel/sched_rt.c +++ b/kernel/sched_rt.c @@ -1136,7 +1136,7 @@ static void put_prev_task_rt(struct rq *rq, struct task_struct *p) * The previous task needs to be made eligible for pushing * if it is still active */ - if (p->se.on_rq && p->rt.nr_cpus_allowed > 1) + if (on_rt_rq(&p->rt) && p->rt.nr_cpus_allowed > 1) enqueue_pushable_task(rq, p); } @@ -1287,7 +1287,7 @@ static struct rq *find_lock_lowest_rq(struct task_struct *task, struct rq *rq) !cpumask_test_cpu(lowest_rq->cpu, &task->cpus_allowed) || task_running(rq, task) || - !task->se.on_rq)) { + !task->on_rq)) { raw_spin_unlock(&lowest_rq->lock); lowest_rq = NULL; @@ -1321,7 +1321,7 @@ static struct task_struct *pick_next_pushable_task(struct rq *rq) BUG_ON(task_current(rq, p)); BUG_ON(p->rt.nr_cpus_allowed <= 1); - BUG_ON(!p->se.on_rq); + BUG_ON(!p->on_rq); BUG_ON(!rt_task(p)); return p; @@ -1467,7 +1467,7 @@ static int pull_rt_task(struct rq *this_rq) */ if (p && (p->prio < this_rq->rt.highest_prio.curr)) { WARN_ON(p == src_rq->curr); - WARN_ON(!p->se.on_rq); + WARN_ON(!p->on_rq); /* * There's a chance that p is higher in priority @@ -1538,7 +1538,7 @@ static void set_cpus_allowed_rt(struct task_struct *p, * Update the migration status of the RQ if we have an RT task * which is running AND changing its weight value. */ - if (p->se.on_rq && (weight != p->rt.nr_cpus_allowed)) { + if (p->on_rq && (weight != p->rt.nr_cpus_allowed)) { struct rq *rq = task_rq(p); if (!task_current(rq, p)) { @@ -1608,7 +1608,7 @@ static void switched_from_rt(struct rq *rq, struct task_struct *p) * we may need to handle the pulling of RT tasks * now. */ - if (p->se.on_rq && !rq->rt.rt_nr_running) + if (p->on_rq && !rq->rt.rt_nr_running) pull_rt_task(rq); } @@ -1638,7 +1638,7 @@ static void switched_to_rt(struct rq *rq, struct task_struct *p) * If that current running task is also an RT task * then see if we can move to another run queue. */ - if (p->se.on_rq && rq->curr != p) { + if (p->on_rq && rq->curr != p) { #ifdef CONFIG_SMP if (rq->rt.overloaded && push_rt_task(rq) && /* Don't resched if we changed runqueues */ @@ -1657,7 +1657,7 @@ static void switched_to_rt(struct rq *rq, struct task_struct *p) static void prio_changed_rt(struct rq *rq, struct task_struct *p, int oldprio) { - if (!p->se.on_rq) + if (!p->on_rq) return; if (rq->curr == p) { diff --git a/kernel/sched_stoptask.c b/kernel/sched_stoptask.c index 1ba2bd4..f607de4 100644 --- a/kernel/sched_stoptask.c +++ b/kernel/sched_stoptask.c @@ -26,7 +26,7 @@ static struct task_struct *pick_next_task_stop(struct rq *rq) { struct task_struct *stop = rq->stop; - if (stop && stop->se.on_rq) + if (stop && stop->on_rq) return stop; return NULL; -- cgit v1.1 From 013fdb8086acaae5f8eb96f9ad48fcd98882ac46 Mon Sep 17 00:00:00 2001 From: Peter Zijlstra Date: Tue, 5 Apr 2011 17:23:45 +0200 Subject: sched: Serialize p->cpus_allowed and ttwu() using p->pi_lock Currently p->pi_lock already serializes p->sched_class, also put p->cpus_allowed and try_to_wake_up() under it, this prepares the way to do the first part of ttwu() without holding rq->lock. By having p->sched_class and p->cpus_allowed serialized by p->pi_lock, we prepare the way to call select_task_rq() without holding rq->lock. Reviewed-by: Frank Rowand Signed-off-by: Peter Zijlstra Cc: Mike Galbraith Cc: Nick Piggin Cc: Linus Torvalds Cc: Andrew Morton Link: http://lkml.kernel.org/r/20110405152728.990364093@chello.nl Signed-off-by: Ingo Molnar --- kernel/sched.c | 37 ++++++++++++++++--------------------- 1 file changed, 16 insertions(+), 21 deletions(-) (limited to 'kernel') diff --git a/kernel/sched.c b/kernel/sched.c index dece28e..d398f2f 100644 --- a/kernel/sched.c +++ b/kernel/sched.c @@ -2340,7 +2340,7 @@ EXPORT_SYMBOL_GPL(kick_process); #ifdef CONFIG_SMP /* - * ->cpus_allowed is protected by either TASK_WAKING or rq->lock held. + * ->cpus_allowed is protected by both rq->lock and p->pi_lock */ static int select_fallback_rq(int cpu, struct task_struct *p) { @@ -2373,7 +2373,7 @@ static int select_fallback_rq(int cpu, struct task_struct *p) } /* - * The caller (fork, wakeup) owns TASK_WAKING, ->cpus_allowed is stable. + * The caller (fork, wakeup) owns p->pi_lock, ->cpus_allowed is stable. */ static inline int select_task_rq(struct rq *rq, struct task_struct *p, int sd_flags, int wake_flags) @@ -2499,7 +2499,8 @@ static int try_to_wake_up(struct task_struct *p, unsigned int state, this_cpu = get_cpu(); smp_wmb(); - rq = task_rq_lock(p, &flags); + raw_spin_lock_irqsave(&p->pi_lock, flags); + rq = __task_rq_lock(p); if (!(p->state & state)) goto out; @@ -2557,7 +2558,8 @@ out_running: ttwu_stat(rq, p, cpu, wake_flags); success = 1; out: - task_rq_unlock(rq, &flags); + __task_rq_unlock(rq); + raw_spin_unlock_irqrestore(&p->pi_lock, flags); put_cpu(); return success; @@ -4694,6 +4696,8 @@ void rt_mutex_setprio(struct task_struct *p, int prio) BUG_ON(prio < 0 || prio > MAX_PRIO); + lockdep_assert_held(&p->pi_lock); + rq = task_rq_lock(p, &flags); trace_sched_pi_setprio(p, prio); @@ -5317,7 +5321,6 @@ long sched_getaffinity(pid_t pid, struct cpumask *mask) { struct task_struct *p; unsigned long flags; - struct rq *rq; int retval; get_online_cpus(); @@ -5332,9 +5335,9 @@ long sched_getaffinity(pid_t pid, struct cpumask *mask) if (retval) goto out_unlock; - rq = task_rq_lock(p, &flags); + raw_spin_lock_irqsave(&p->pi_lock, flags); cpumask_and(mask, &p->cpus_allowed, cpu_online_mask); - task_rq_unlock(rq, &flags); + raw_spin_unlock_irqrestore(&p->pi_lock, flags); out_unlock: rcu_read_unlock(); @@ -5882,18 +5885,8 @@ int set_cpus_allowed_ptr(struct task_struct *p, const struct cpumask *new_mask) unsigned int dest_cpu; int ret = 0; - /* - * Serialize against TASK_WAKING so that ttwu() and wunt() can - * drop the rq->lock and still rely on ->cpus_allowed. - */ -again: - while (task_is_waking(p)) - cpu_relax(); - rq = task_rq_lock(p, &flags); - if (task_is_waking(p)) { - task_rq_unlock(rq, &flags); - goto again; - } + raw_spin_lock_irqsave(&p->pi_lock, flags); + rq = __task_rq_lock(p); if (!cpumask_intersects(new_mask, cpu_active_mask)) { ret = -EINVAL; @@ -5921,13 +5914,15 @@ again: if (migrate_task(p, rq)) { struct migration_arg arg = { p, dest_cpu }; /* Need help from migration thread: drop lock and wait. */ - task_rq_unlock(rq, &flags); + __task_rq_unlock(rq); + raw_spin_unlock_irqrestore(&p->pi_lock, flags); stop_one_cpu(cpu_of(rq), migration_cpu_stop, &arg); tlb_migrate_finish(p->mm); return 0; } out: - task_rq_unlock(rq, &flags); + __task_rq_unlock(rq); + raw_spin_unlock_irqrestore(&p->pi_lock, flags); return ret; } -- cgit v1.1 From 7608dec2ce2004c234339bef8c8074e5e601d0e9 Mon Sep 17 00:00:00 2001 From: Peter Zijlstra Date: Tue, 5 Apr 2011 17:23:46 +0200 Subject: sched: Drop the rq argument to sched_class::select_task_rq() In preparation of calling select_task_rq() without rq->lock held, drop the dependency on the rq argument. Reviewed-by: Frank Rowand Signed-off-by: Peter Zijlstra Cc: Mike Galbraith Cc: Nick Piggin Cc: Linus Torvalds Cc: Andrew Morton Link: http://lkml.kernel.org/r/20110405152729.031077745@chello.nl Signed-off-by: Ingo Molnar --- kernel/sched.c | 20 +++++++++++--------- kernel/sched_fair.c | 2 +- kernel/sched_idletask.c | 2 +- kernel/sched_rt.c | 38 ++++++++++++++++++++++++++------------ kernel/sched_stoptask.c | 3 +-- 5 files changed, 40 insertions(+), 25 deletions(-) (limited to 'kernel') diff --git a/kernel/sched.c b/kernel/sched.c index d398f2f..d4b815d 100644 --- a/kernel/sched.c +++ b/kernel/sched.c @@ -2195,13 +2195,15 @@ static int migration_cpu_stop(void *data); * The task's runqueue lock must be held. * Returns true if you have to wait for migration thread. */ -static bool migrate_task(struct task_struct *p, struct rq *rq) +static bool need_migrate_task(struct task_struct *p) { /* * If the task is not on a runqueue (and not running), then * the next wake-up will properly place the task. */ - return p->on_rq || task_running(rq, p); + bool running = p->on_rq || p->on_cpu; + smp_rmb(); /* finish_lock_switch() */ + return running; } /* @@ -2376,9 +2378,9 @@ static int select_fallback_rq(int cpu, struct task_struct *p) * The caller (fork, wakeup) owns p->pi_lock, ->cpus_allowed is stable. */ static inline -int select_task_rq(struct rq *rq, struct task_struct *p, int sd_flags, int wake_flags) +int select_task_rq(struct task_struct *p, int sd_flags, int wake_flags) { - int cpu = p->sched_class->select_task_rq(rq, p, sd_flags, wake_flags); + int cpu = p->sched_class->select_task_rq(p, sd_flags, wake_flags); /* * In order not to call set_task_cpu() on a blocking task we need @@ -2533,7 +2535,7 @@ static int try_to_wake_up(struct task_struct *p, unsigned int state, en_flags |= ENQUEUE_WAKING; } - cpu = select_task_rq(rq, p, SD_BALANCE_WAKE, wake_flags); + cpu = select_task_rq(p, SD_BALANCE_WAKE, wake_flags); if (cpu != orig_cpu) set_task_cpu(p, cpu); __task_rq_unlock(rq); @@ -2744,7 +2746,7 @@ void wake_up_new_task(struct task_struct *p, unsigned long clone_flags) * We set TASK_WAKING so that select_task_rq() can drop rq->lock * without people poking at ->cpus_allowed. */ - cpu = select_task_rq(rq, p, SD_BALANCE_FORK, 0); + cpu = select_task_rq(p, SD_BALANCE_FORK, 0); set_task_cpu(p, cpu); p->state = TASK_RUNNING; @@ -3474,7 +3476,7 @@ void sched_exec(void) int dest_cpu; rq = task_rq_lock(p, &flags); - dest_cpu = p->sched_class->select_task_rq(rq, p, SD_BALANCE_EXEC, 0); + dest_cpu = p->sched_class->select_task_rq(p, SD_BALANCE_EXEC, 0); if (dest_cpu == smp_processor_id()) goto unlock; @@ -3482,7 +3484,7 @@ void sched_exec(void) * select_task_rq() can race against ->cpus_allowed */ if (cpumask_test_cpu(dest_cpu, &p->cpus_allowed) && - likely(cpu_active(dest_cpu)) && migrate_task(p, rq)) { + likely(cpu_active(dest_cpu)) && need_migrate_task(p)) { struct migration_arg arg = { p, dest_cpu }; task_rq_unlock(rq, &flags); @@ -5911,7 +5913,7 @@ int set_cpus_allowed_ptr(struct task_struct *p, const struct cpumask *new_mask) goto out; dest_cpu = cpumask_any_and(cpu_active_mask, new_mask); - if (migrate_task(p, rq)) { + if (need_migrate_task(p)) { struct migration_arg arg = { p, dest_cpu }; /* Need help from migration thread: drop lock and wait. */ __task_rq_unlock(rq); diff --git a/kernel/sched_fair.c b/kernel/sched_fair.c index 4ee50f0..96b2c95 100644 --- a/kernel/sched_fair.c +++ b/kernel/sched_fair.c @@ -1657,7 +1657,7 @@ static int select_idle_sibling(struct task_struct *p, int target) * preempt must be disabled. */ static int -select_task_rq_fair(struct rq *rq, struct task_struct *p, int sd_flag, int wake_flags) +select_task_rq_fair(struct task_struct *p, int sd_flag, int wake_flags) { struct sched_domain *tmp, *affine_sd = NULL, *sd = NULL; int cpu = smp_processor_id(); diff --git a/kernel/sched_idletask.c b/kernel/sched_idletask.c index a776a63..0a51882 100644 --- a/kernel/sched_idletask.c +++ b/kernel/sched_idletask.c @@ -7,7 +7,7 @@ #ifdef CONFIG_SMP static int -select_task_rq_idle(struct rq *rq, struct task_struct *p, int sd_flag, int flags) +select_task_rq_idle(struct task_struct *p, int sd_flag, int flags) { return task_cpu(p); /* IDLE tasks as never migrated */ } diff --git a/kernel/sched_rt.c b/kernel/sched_rt.c index 9ca4f5f..19ecb31 100644 --- a/kernel/sched_rt.c +++ b/kernel/sched_rt.c @@ -977,13 +977,23 @@ static void yield_task_rt(struct rq *rq) static int find_lowest_rq(struct task_struct *task); static int -select_task_rq_rt(struct rq *rq, struct task_struct *p, int sd_flag, int flags) +select_task_rq_rt(struct task_struct *p, int sd_flag, int flags) { + struct task_struct *curr; + struct rq *rq; + int cpu; + if (sd_flag != SD_BALANCE_WAKE) return smp_processor_id(); + cpu = task_cpu(p); + rq = cpu_rq(cpu); + + rcu_read_lock(); + curr = ACCESS_ONCE(rq->curr); /* unlocked access */ + /* - * If the current task is an RT task, then + * If the current task on @p's runqueue is an RT task, then * try to see if we can wake this RT task up on another * runqueue. Otherwise simply start this RT task * on its current runqueue. @@ -997,21 +1007,25 @@ select_task_rq_rt(struct rq *rq, struct task_struct *p, int sd_flag, int flags) * lock? * * For equal prio tasks, we just let the scheduler sort it out. + * + * Otherwise, just let it ride on the affined RQ and the + * post-schedule router will push the preempted task away + * + * This test is optimistic, if we get it wrong the load-balancer + * will have to sort it out. */ - if (unlikely(rt_task(rq->curr)) && - (rq->curr->rt.nr_cpus_allowed < 2 || - rq->curr->prio < p->prio) && + if (curr && unlikely(rt_task(curr)) && + (curr->rt.nr_cpus_allowed < 2 || + curr->prio < p->prio) && (p->rt.nr_cpus_allowed > 1)) { - int cpu = find_lowest_rq(p); + int target = find_lowest_rq(p); - return (cpu == -1) ? task_cpu(p) : cpu; + if (target != -1) + cpu = target; } + rcu_read_unlock(); - /* - * Otherwise, just let it ride on the affined RQ and the - * post-schedule router will push the preempted task away - */ - return task_cpu(p); + return cpu; } static void check_preempt_equal_prio(struct rq *rq, struct task_struct *p) diff --git a/kernel/sched_stoptask.c b/kernel/sched_stoptask.c index f607de4..6f43763 100644 --- a/kernel/sched_stoptask.c +++ b/kernel/sched_stoptask.c @@ -9,8 +9,7 @@ #ifdef CONFIG_SMP static int -select_task_rq_stop(struct rq *rq, struct task_struct *p, - int sd_flag, int flags) +select_task_rq_stop(struct task_struct *p, int sd_flag, int flags) { return task_cpu(p); /* stop tasks as never migrate */ } -- cgit v1.1 From 74f8e4b2335de45485b8d5b31a504747f13c8070 Mon Sep 17 00:00:00 2001 From: Peter Zijlstra Date: Tue, 5 Apr 2011 17:23:47 +0200 Subject: sched: Remove rq argument to sched_class::task_waking() In preparation of calling this without rq->lock held, remove the dependency on the rq argument. Reviewed-by: Frank Rowand Signed-off-by: Peter Zijlstra Cc: Mike Galbraith Cc: Nick Piggin Cc: Linus Torvalds Cc: Andrew Morton Link: http://lkml.kernel.org/r/20110405152729.071474242@chello.nl Signed-off-by: Ingo Molnar --- kernel/sched.c | 2 +- kernel/sched_fair.c | 4 +++- 2 files changed, 4 insertions(+), 2 deletions(-) (limited to 'kernel') diff --git a/kernel/sched.c b/kernel/sched.c index d4b815d..46f42ca 100644 --- a/kernel/sched.c +++ b/kernel/sched.c @@ -2531,7 +2531,7 @@ static int try_to_wake_up(struct task_struct *p, unsigned int state, p->state = TASK_WAKING; if (p->sched_class->task_waking) { - p->sched_class->task_waking(rq, p); + p->sched_class->task_waking(p); en_flags |= ENQUEUE_WAKING; } diff --git a/kernel/sched_fair.c b/kernel/sched_fair.c index 96b2c95..ad4c414f 100644 --- a/kernel/sched_fair.c +++ b/kernel/sched_fair.c @@ -1372,11 +1372,13 @@ static void dequeue_task_fair(struct rq *rq, struct task_struct *p, int flags) #ifdef CONFIG_SMP -static void task_waking_fair(struct rq *rq, struct task_struct *p) +static void task_waking_fair(struct task_struct *p) { struct sched_entity *se = &p->se; struct cfs_rq *cfs_rq = cfs_rq_of(se); + lockdep_assert_held(&task_rq(p)->lock); + se->vruntime -= cfs_rq->min_vruntime; } -- cgit v1.1 From 3fe1698b7fe05aeb063564e71e40d09f28d8e80c Mon Sep 17 00:00:00 2001 From: Peter Zijlstra Date: Tue, 5 Apr 2011 17:23:48 +0200 Subject: sched: Deal with non-atomic min_vruntime reads on 32bits In order to avoid reading partial updated min_vruntime values on 32bit implement a seqcount like solution. Reviewed-by: Frank Rowand Signed-off-by: Peter Zijlstra Cc: Mike Galbraith Cc: Nick Piggin Cc: Linus Torvalds Cc: Andrew Morton Link: http://lkml.kernel.org/r/20110405152729.111378493@chello.nl Signed-off-by: Ingo Molnar --- kernel/sched.c | 3 +++ kernel/sched_fair.c | 19 +++++++++++++++++-- 2 files changed, 20 insertions(+), 2 deletions(-) (limited to 'kernel') diff --git a/kernel/sched.c b/kernel/sched.c index 46f42ca..7a5eb26 100644 --- a/kernel/sched.c +++ b/kernel/sched.c @@ -312,6 +312,9 @@ struct cfs_rq { u64 exec_clock; u64 min_vruntime; +#ifndef CONFIG_64BIT + u64 min_vruntime_copy; +#endif struct rb_root tasks_timeline; struct rb_node *rb_leftmost; diff --git a/kernel/sched_fair.c b/kernel/sched_fair.c index ad4c414f..054cebb 100644 --- a/kernel/sched_fair.c +++ b/kernel/sched_fair.c @@ -358,6 +358,10 @@ static void update_min_vruntime(struct cfs_rq *cfs_rq) } cfs_rq->min_vruntime = max_vruntime(cfs_rq->min_vruntime, vruntime); +#ifndef CONFIG_64BIT + smp_wmb(); + cfs_rq->min_vruntime_copy = cfs_rq->min_vruntime; +#endif } /* @@ -1376,10 +1380,21 @@ static void task_waking_fair(struct task_struct *p) { struct sched_entity *se = &p->se; struct cfs_rq *cfs_rq = cfs_rq_of(se); + u64 min_vruntime; - lockdep_assert_held(&task_rq(p)->lock); +#ifndef CONFIG_64BIT + u64 min_vruntime_copy; - se->vruntime -= cfs_rq->min_vruntime; + do { + min_vruntime_copy = cfs_rq->min_vruntime_copy; + smp_rmb(); + min_vruntime = cfs_rq->min_vruntime; + } while (min_vruntime != min_vruntime_copy); +#else + min_vruntime = cfs_rq->min_vruntime; +#endif + + se->vruntime -= min_vruntime; } #ifdef CONFIG_FAIR_GROUP_SCHED -- cgit v1.1 From a8e4f2eaecc9bfa4954adf79a04f4f22fddd829c Mon Sep 17 00:00:00 2001 From: Peter Zijlstra Date: Tue, 5 Apr 2011 17:23:49 +0200 Subject: sched: Delay task_contributes_to_load() In prepratation of having to call task_contributes_to_load() without holding rq->lock, we need to store the result until we do and can update the rq accounting accordingly. Reviewed-by: Frank Rowand Cc: Mike Galbraith Cc: Nick Piggin Cc: Linus Torvalds Cc: Andrew Morton Signed-off-by: Ingo Molnar Signed-off-by: Peter Zijlstra Link: http://lkml.kernel.org/r/20110405152729.151523907@chello.nl --- kernel/sched.c | 16 ++++------------ 1 file changed, 4 insertions(+), 12 deletions(-) (limited to 'kernel') diff --git a/kernel/sched.c b/kernel/sched.c index 7a5eb26..fd32b78 100644 --- a/kernel/sched.c +++ b/kernel/sched.c @@ -2519,18 +2519,7 @@ static int try_to_wake_up(struct task_struct *p, unsigned int state, if (unlikely(task_running(rq, p))) goto out_activate; - /* - * In order to handle concurrent wakeups and release the rq->lock - * we put the task in TASK_WAKING state. - * - * First fix up the nr_uninterruptible count: - */ - if (task_contributes_to_load(p)) { - if (likely(cpu_online(orig_cpu))) - rq->nr_uninterruptible--; - else - this_rq()->nr_uninterruptible--; - } + p->sched_contributes_to_load = !!task_contributes_to_load(p); p->state = TASK_WAKING; if (p->sched_class->task_waking) { @@ -2555,6 +2544,9 @@ static int try_to_wake_up(struct task_struct *p, unsigned int state, WARN_ON(task_cpu(p) != cpu); WARN_ON(p->state != TASK_WAKING); + if (p->sched_contributes_to_load) + rq->nr_uninterruptible--; + out_activate: #endif /* CONFIG_SMP */ ttwu_activate(rq, p, en_flags); -- cgit v1.1 From 2acca55ed98ad9b9aa25e7e587ebe306c0313dc7 Mon Sep 17 00:00:00 2001 From: Peter Zijlstra Date: Tue, 5 Apr 2011 17:23:50 +0200 Subject: sched: Also serialize ttwu_local() with p->pi_lock Since we now serialize ttwu() using p->pi_lock, we also need to serialize ttwu_local() using that, otherwise, once we drop the rq->lock from ttwu() it can race with ttwu_local(). Reviewed-by: Frank Rowand Cc: Mike Galbraith Cc: Nick Piggin Cc: Linus Torvalds Cc: Andrew Morton Signed-off-by: Ingo Molnar Signed-off-by: Peter Zijlstra Link: http://lkml.kernel.org/r/20110405152729.192366907@chello.nl --- kernel/sched.c | 31 +++++++++++++++++++------------ 1 file changed, 19 insertions(+), 12 deletions(-) (limited to 'kernel') diff --git a/kernel/sched.c b/kernel/sched.c index fd32b78..6b269b7 100644 --- a/kernel/sched.c +++ b/kernel/sched.c @@ -2566,9 +2566,9 @@ out: * try_to_wake_up_local - try to wake up a local task with rq lock held * @p: the thread to be awakened * - * Put @p on the run-queue if it's not already there. The caller must + * Put @p on the run-queue if it's not already there. The caller must * ensure that this_rq() is locked, @p is bound to this_rq() and not - * the current task. this_rq() stays locked over invocation. + * the current task. */ static void try_to_wake_up_local(struct task_struct *p) { @@ -2578,14 +2578,22 @@ static void try_to_wake_up_local(struct task_struct *p) BUG_ON(p == current); lockdep_assert_held(&rq->lock); + if (!raw_spin_trylock(&p->pi_lock)) { + raw_spin_unlock(&rq->lock); + raw_spin_lock(&p->pi_lock); + raw_spin_lock(&rq->lock); + } + if (!(p->state & TASK_NORMAL)) - return; + goto out; if (!p->on_rq) ttwu_activate(rq, p, ENQUEUE_WAKEUP); ttwu_post_activation(p, rq, 0); ttwu_stat(rq, p, smp_processor_id(), 0); +out: + raw_spin_unlock(&p->pi_lock); } /** @@ -4114,11 +4122,13 @@ need_resched: if (unlikely(signal_pending_state(prev->state, prev))) { prev->state = TASK_RUNNING; } else { + deactivate_task(rq, prev, DEQUEUE_SLEEP); + prev->on_rq = 0; + /* - * If a worker is going to sleep, notify and - * ask workqueue whether it wants to wake up a - * task to maintain concurrency. If so, wake - * up the task. + * If a worker went to sleep, notify and ask workqueue + * whether it wants to wake up a task to maintain + * concurrency. */ if (prev->flags & PF_WQ_WORKER) { struct task_struct *to_wakeup; @@ -4128,12 +4138,9 @@ need_resched: try_to_wake_up_local(to_wakeup); } - deactivate_task(rq, prev, DEQUEUE_SLEEP); - prev->on_rq = 0; - /* - * If we are going to sleep and we have plugged IO queued, make - * sure to submit it to avoid deadlocks. + * If we are going to sleep and we have plugged IO + * queued, make sure to submit it to avoid deadlocks. */ if (blk_needs_flush_plug(prev)) { raw_spin_unlock(&rq->lock); -- cgit v1.1 From 0122ec5b02f766c355b3168df53a6c038a24fa0d Mon Sep 17 00:00:00 2001 From: Peter Zijlstra Date: Tue, 5 Apr 2011 17:23:51 +0200 Subject: sched: Add p->pi_lock to task_rq_lock() In order to be able to call set_task_cpu() while either holding p->pi_lock or task_rq(p)->lock we need to hold both locks in order to stabilize task_rq(). This makes task_rq_lock() acquire both locks, and have __task_rq_lock() validate that p->pi_lock is held. This increases the locking overhead for most scheduler syscalls but allows reduction of rq->lock contention for some scheduler hot paths (ttwu). Reviewed-by: Frank Rowand Signed-off-by: Peter Zijlstra Cc: Mike Galbraith Cc: Nick Piggin Cc: Linus Torvalds Cc: Andrew Morton Link: http://lkml.kernel.org/r/20110405152729.232781355@chello.nl Signed-off-by: Ingo Molnar --- kernel/sched.c | 103 ++++++++++++++++++++++++++------------------------------- 1 file changed, 47 insertions(+), 56 deletions(-) (limited to 'kernel') diff --git a/kernel/sched.c b/kernel/sched.c index 6b269b7..f155127 100644 --- a/kernel/sched.c +++ b/kernel/sched.c @@ -599,7 +599,7 @@ static inline int cpu_of(struct rq *rq) * Return the group to which this tasks belongs. * * We use task_subsys_state_check() and extend the RCU verification - * with lockdep_is_held(&task_rq(p)->lock) because cpu_cgroup_attach() + * with lockdep_is_held(&p->pi_lock) because cpu_cgroup_attach() * holds that lock for each task it moves into the cgroup. Therefore * by holding that lock, we pin the task to the current cgroup. */ @@ -609,7 +609,7 @@ static inline struct task_group *task_group(struct task_struct *p) struct cgroup_subsys_state *css; css = task_subsys_state_check(p, cpu_cgroup_subsys_id, - lockdep_is_held(&task_rq(p)->lock)); + lockdep_is_held(&p->pi_lock)); tg = container_of(css, struct task_group, css); return autogroup_task_group(p, tg); @@ -924,23 +924,15 @@ static inline void finish_lock_switch(struct rq *rq, struct task_struct *prev) #endif /* __ARCH_WANT_UNLOCKED_CTXSW */ /* - * Check whether the task is waking, we use this to synchronize ->cpus_allowed - * against ttwu(). - */ -static inline int task_is_waking(struct task_struct *p) -{ - return unlikely(p->state == TASK_WAKING); -} - -/* - * __task_rq_lock - lock the runqueue a given task resides on. - * Must be called interrupts disabled. + * __task_rq_lock - lock the rq @p resides on. */ static inline struct rq *__task_rq_lock(struct task_struct *p) __acquires(rq->lock) { struct rq *rq; + lockdep_assert_held(&p->pi_lock); + for (;;) { rq = task_rq(p); raw_spin_lock(&rq->lock); @@ -951,22 +943,22 @@ static inline struct rq *__task_rq_lock(struct task_struct *p) } /* - * task_rq_lock - lock the runqueue a given task resides on and disable - * interrupts. Note the ordering: we can safely lookup the task_rq without - * explicitly disabling preemption. + * task_rq_lock - lock p->pi_lock and lock the rq @p resides on. */ static struct rq *task_rq_lock(struct task_struct *p, unsigned long *flags) + __acquires(p->pi_lock) __acquires(rq->lock) { struct rq *rq; for (;;) { - local_irq_save(*flags); + raw_spin_lock_irqsave(&p->pi_lock, *flags); rq = task_rq(p); raw_spin_lock(&rq->lock); if (likely(rq == task_rq(p))) return rq; - raw_spin_unlock_irqrestore(&rq->lock, *flags); + raw_spin_unlock(&rq->lock); + raw_spin_unlock_irqrestore(&p->pi_lock, *flags); } } @@ -976,10 +968,13 @@ static void __task_rq_unlock(struct rq *rq) raw_spin_unlock(&rq->lock); } -static inline void task_rq_unlock(struct rq *rq, unsigned long *flags) +static inline void +task_rq_unlock(struct rq *rq, struct task_struct *p, unsigned long *flags) __releases(rq->lock) + __releases(p->pi_lock) { - raw_spin_unlock_irqrestore(&rq->lock, *flags); + raw_spin_unlock(&rq->lock); + raw_spin_unlock_irqrestore(&p->pi_lock, *flags); } /* @@ -2175,6 +2170,11 @@ void set_task_cpu(struct task_struct *p, unsigned int new_cpu) */ WARN_ON_ONCE(p->state != TASK_RUNNING && p->state != TASK_WAKING && !(task_thread_info(p)->preempt_count & PREEMPT_ACTIVE)); + +#ifdef CONFIG_LOCKDEP + WARN_ON_ONCE(debug_locks && !(lockdep_is_held(&p->pi_lock) || + lockdep_is_held(&task_rq(p)->lock))); +#endif #endif trace_sched_migrate_task(p, new_cpu); @@ -2270,7 +2270,7 @@ unsigned long wait_task_inactive(struct task_struct *p, long match_state) ncsw = 0; if (!match_state || p->state == match_state) ncsw = p->nvcsw | LONG_MIN; /* sets MSB */ - task_rq_unlock(rq, &flags); + task_rq_unlock(rq, p, &flags); /* * If it changed from the expected state, bail out now. @@ -2652,6 +2652,7 @@ static void __sched_fork(struct task_struct *p) */ void sched_fork(struct task_struct *p, int clone_flags) { + unsigned long flags; int cpu = get_cpu(); __sched_fork(p); @@ -2702,9 +2703,9 @@ void sched_fork(struct task_struct *p, int clone_flags) * * Silence PROVE_RCU. */ - rcu_read_lock(); + raw_spin_lock_irqsave(&p->pi_lock, flags); set_task_cpu(p, cpu); - rcu_read_unlock(); + raw_spin_unlock_irqrestore(&p->pi_lock, flags); #if defined(CONFIG_SCHEDSTATS) || defined(CONFIG_TASK_DELAY_ACCT) if (likely(sched_info_on())) @@ -2753,7 +2754,7 @@ void wake_up_new_task(struct task_struct *p, unsigned long clone_flags) set_task_cpu(p, cpu); p->state = TASK_RUNNING; - task_rq_unlock(rq, &flags); + task_rq_unlock(rq, p, &flags); #endif rq = task_rq_lock(p, &flags); @@ -2765,7 +2766,7 @@ void wake_up_new_task(struct task_struct *p, unsigned long clone_flags) if (p->sched_class->task_woken) p->sched_class->task_woken(rq, p); #endif - task_rq_unlock(rq, &flags); + task_rq_unlock(rq, p, &flags); put_cpu(); } @@ -3490,12 +3491,12 @@ void sched_exec(void) likely(cpu_active(dest_cpu)) && need_migrate_task(p)) { struct migration_arg arg = { p, dest_cpu }; - task_rq_unlock(rq, &flags); + task_rq_unlock(rq, p, &flags); stop_one_cpu(cpu_of(rq), migration_cpu_stop, &arg); return; } unlock: - task_rq_unlock(rq, &flags); + task_rq_unlock(rq, p, &flags); } #endif @@ -3532,7 +3533,7 @@ unsigned long long task_delta_exec(struct task_struct *p) rq = task_rq_lock(p, &flags); ns = do_task_delta_exec(p, rq); - task_rq_unlock(rq, &flags); + task_rq_unlock(rq, p, &flags); return ns; } @@ -3550,7 +3551,7 @@ unsigned long long task_sched_runtime(struct task_struct *p) rq = task_rq_lock(p, &flags); ns = p->se.sum_exec_runtime + do_task_delta_exec(p, rq); - task_rq_unlock(rq, &flags); + task_rq_unlock(rq, p, &flags); return ns; } @@ -3574,7 +3575,7 @@ unsigned long long thread_group_sched_runtime(struct task_struct *p) rq = task_rq_lock(p, &flags); thread_group_cputime(p, &totals); ns = totals.sum_exec_runtime + do_task_delta_exec(p, rq); - task_rq_unlock(rq, &flags); + task_rq_unlock(rq, p, &flags); return ns; } @@ -4693,16 +4694,13 @@ EXPORT_SYMBOL(sleep_on_timeout); */ void rt_mutex_setprio(struct task_struct *p, int prio) { - unsigned long flags; int oldprio, on_rq, running; struct rq *rq; const struct sched_class *prev_class; BUG_ON(prio < 0 || prio > MAX_PRIO); - lockdep_assert_held(&p->pi_lock); - - rq = task_rq_lock(p, &flags); + rq = __task_rq_lock(p); trace_sched_pi_setprio(p, prio); oldprio = p->prio; @@ -4727,7 +4725,7 @@ void rt_mutex_setprio(struct task_struct *p, int prio) enqueue_task(rq, p, oldprio < prio ? ENQUEUE_HEAD : 0); check_class_changed(rq, p, prev_class, oldprio); - task_rq_unlock(rq, &flags); + __task_rq_unlock(rq); } #endif @@ -4775,7 +4773,7 @@ void set_user_nice(struct task_struct *p, long nice) resched_task(rq->curr); } out_unlock: - task_rq_unlock(rq, &flags); + task_rq_unlock(rq, p, &flags); } EXPORT_SYMBOL(set_user_nice); @@ -5003,20 +5001,17 @@ recheck: /* * make sure no PI-waiters arrive (or leave) while we are * changing the priority of the task: - */ - raw_spin_lock_irqsave(&p->pi_lock, flags); - /* + * * To be able to change p->policy safely, the appropriate * runqueue lock must be held. */ - rq = __task_rq_lock(p); + rq = task_rq_lock(p, &flags); /* * Changing the policy of the stop threads its a very bad idea */ if (p == rq->stop) { - __task_rq_unlock(rq); - raw_spin_unlock_irqrestore(&p->pi_lock, flags); + task_rq_unlock(rq, p, &flags); return -EINVAL; } @@ -5040,8 +5035,7 @@ recheck: if (rt_bandwidth_enabled() && rt_policy(policy) && task_group(p)->rt_bandwidth.rt_runtime == 0 && !task_group_is_autogroup(task_group(p))) { - __task_rq_unlock(rq); - raw_spin_unlock_irqrestore(&p->pi_lock, flags); + task_rq_unlock(rq, p, &flags); return -EPERM; } } @@ -5050,8 +5044,7 @@ recheck: /* recheck policy now with rq lock held */ if (unlikely(oldpolicy != -1 && oldpolicy != p->policy)) { policy = oldpolicy = -1; - __task_rq_unlock(rq); - raw_spin_unlock_irqrestore(&p->pi_lock, flags); + task_rq_unlock(rq, p, &flags); goto recheck; } on_rq = p->on_rq; @@ -5073,8 +5066,7 @@ recheck: activate_task(rq, p, 0); check_class_changed(rq, p, prev_class, oldprio); - __task_rq_unlock(rq); - raw_spin_unlock_irqrestore(&p->pi_lock, flags); + task_rq_unlock(rq, p, &flags); rt_mutex_adjust_pi(p); @@ -5666,7 +5658,7 @@ SYSCALL_DEFINE2(sched_rr_get_interval, pid_t, pid, rq = task_rq_lock(p, &flags); time_slice = p->sched_class->get_rr_interval(rq, p); - task_rq_unlock(rq, &flags); + task_rq_unlock(rq, p, &flags); rcu_read_unlock(); jiffies_to_timespec(time_slice, &t); @@ -5889,8 +5881,7 @@ int set_cpus_allowed_ptr(struct task_struct *p, const struct cpumask *new_mask) unsigned int dest_cpu; int ret = 0; - raw_spin_lock_irqsave(&p->pi_lock, flags); - rq = __task_rq_lock(p); + rq = task_rq_lock(p, &flags); if (!cpumask_intersects(new_mask, cpu_active_mask)) { ret = -EINVAL; @@ -5918,15 +5909,13 @@ int set_cpus_allowed_ptr(struct task_struct *p, const struct cpumask *new_mask) if (need_migrate_task(p)) { struct migration_arg arg = { p, dest_cpu }; /* Need help from migration thread: drop lock and wait. */ - __task_rq_unlock(rq); - raw_spin_unlock_irqrestore(&p->pi_lock, flags); + task_rq_unlock(rq, p, &flags); stop_one_cpu(cpu_of(rq), migration_cpu_stop, &arg); tlb_migrate_finish(p->mm); return 0; } out: - __task_rq_unlock(rq); - raw_spin_unlock_irqrestore(&p->pi_lock, flags); + task_rq_unlock(rq, p, &flags); return ret; } @@ -5954,6 +5943,7 @@ static int __migrate_task(struct task_struct *p, int src_cpu, int dest_cpu) rq_src = cpu_rq(src_cpu); rq_dest = cpu_rq(dest_cpu); + raw_spin_lock(&p->pi_lock); double_rq_lock(rq_src, rq_dest); /* Already moved. */ if (task_cpu(p) != src_cpu) @@ -5976,6 +5966,7 @@ done: ret = 1; fail: double_rq_unlock(rq_src, rq_dest); + raw_spin_unlock(&p->pi_lock); return ret; } @@ -8702,7 +8693,7 @@ void sched_move_task(struct task_struct *tsk) if (on_rq) enqueue_task(rq, tsk, 0); - task_rq_unlock(rq, &flags); + task_rq_unlock(rq, tsk, &flags); } #endif /* CONFIG_CGROUP_SCHED */ -- cgit v1.1 From ab2515c4b98f7bc4fa11cad9fa0f811d63a72a26 Mon Sep 17 00:00:00 2001 From: Peter Zijlstra Date: Tue, 5 Apr 2011 17:23:52 +0200 Subject: sched: Drop rq->lock from first part of wake_up_new_task() Since p->pi_lock now protects all things needed to call select_task_rq() avoid the double remote rq->lock acquisition and rely on p->pi_lock. Reviewed-by: Frank Rowand Signed-off-by: Peter Zijlstra Cc: Mike Galbraith Cc: Nick Piggin Cc: Linus Torvalds Cc: Andrew Morton Link: http://lkml.kernel.org/r/20110405152729.273362517@chello.nl Signed-off-by: Ingo Molnar --- kernel/sched.c | 17 +++-------------- 1 file changed, 3 insertions(+), 14 deletions(-) (limited to 'kernel') diff --git a/kernel/sched.c b/kernel/sched.c index f155127..7c5494d 100644 --- a/kernel/sched.c +++ b/kernel/sched.c @@ -2736,28 +2736,18 @@ void wake_up_new_task(struct task_struct *p, unsigned long clone_flags) { unsigned long flags; struct rq *rq; - int cpu __maybe_unused = get_cpu(); + raw_spin_lock_irqsave(&p->pi_lock, flags); #ifdef CONFIG_SMP - rq = task_rq_lock(p, &flags); - p->state = TASK_WAKING; - /* * Fork balancing, do it here and not earlier because: * - cpus_allowed can change in the fork path * - any previously selected cpu might disappear through hotplug - * - * We set TASK_WAKING so that select_task_rq() can drop rq->lock - * without people poking at ->cpus_allowed. */ - cpu = select_task_rq(p, SD_BALANCE_FORK, 0); - set_task_cpu(p, cpu); - - p->state = TASK_RUNNING; - task_rq_unlock(rq, p, &flags); + set_task_cpu(p, select_task_rq(p, SD_BALANCE_FORK, 0)); #endif - rq = task_rq_lock(p, &flags); + rq = __task_rq_lock(p); activate_task(rq, p, 0); p->on_rq = 1; trace_sched_wakeup_new(p, true); @@ -2767,7 +2757,6 @@ void wake_up_new_task(struct task_struct *p, unsigned long clone_flags) p->sched_class->task_woken(rq, p); #endif task_rq_unlock(rq, p, &flags); - put_cpu(); } #ifdef CONFIG_PREEMPT_NOTIFIERS -- cgit v1.1 From 8f42ced974df7d5af2de4cf5ea21fe978c7e4478 Mon Sep 17 00:00:00 2001 From: Peter Zijlstra Date: Tue, 5 Apr 2011 17:23:53 +0200 Subject: sched: Drop rq->lock from sched_exec() Since we can now call select_task_rq() and set_task_cpu() with only p->pi_lock held, and sched_exec() load-balancing has always been optimistic, drop all rq->lock usage. Oleg also noted that need_migrate_task() will always be true for current, so don't bother calling that at all. Reviewed-by: Frank Rowand Signed-off-by: Peter Zijlstra Cc: Mike Galbraith Cc: Nick Piggin Cc: Linus Torvalds Cc: Andrew Morton Link: http://lkml.kernel.org/r/20110405152729.314204889@chello.nl Signed-off-by: Ingo Molnar --- kernel/sched.c | 15 +++++---------- 1 file changed, 5 insertions(+), 10 deletions(-) (limited to 'kernel') diff --git a/kernel/sched.c b/kernel/sched.c index 7c5494d..1be1a09 100644 --- a/kernel/sched.c +++ b/kernel/sched.c @@ -3465,27 +3465,22 @@ void sched_exec(void) { struct task_struct *p = current; unsigned long flags; - struct rq *rq; int dest_cpu; - rq = task_rq_lock(p, &flags); + raw_spin_lock_irqsave(&p->pi_lock, flags); dest_cpu = p->sched_class->select_task_rq(p, SD_BALANCE_EXEC, 0); if (dest_cpu == smp_processor_id()) goto unlock; - /* - * select_task_rq() can race against ->cpus_allowed - */ - if (cpumask_test_cpu(dest_cpu, &p->cpus_allowed) && - likely(cpu_active(dest_cpu)) && need_migrate_task(p)) { + if (likely(cpu_active(dest_cpu))) { struct migration_arg arg = { p, dest_cpu }; - task_rq_unlock(rq, p, &flags); - stop_one_cpu(cpu_of(rq), migration_cpu_stop, &arg); + raw_spin_unlock_irqrestore(&p->pi_lock, flags); + stop_one_cpu(task_cpu(p), migration_cpu_stop, &arg); return; } unlock: - task_rq_unlock(rq, p, &flags); + raw_spin_unlock_irqrestore(&p->pi_lock, flags); } #endif -- cgit v1.1 From e4a52bcb9a18142d79e231b6733cabdbf2e67c1f Mon Sep 17 00:00:00 2001 From: Peter Zijlstra Date: Tue, 5 Apr 2011 17:23:54 +0200 Subject: sched: Remove rq->lock from the first half of ttwu() Currently ttwu() does two rq->lock acquisitions, once on the task's old rq, holding it over the p->state fiddling and load-balance pass. Then it drops the old rq->lock to acquire the new rq->lock. By having serialized ttwu(), p->sched_class, p->cpus_allowed with p->pi_lock, we can now drop the whole first rq->lock acquisition. The p->pi_lock serializing concurrent ttwu() calls protects p->state, which we will set to TASK_WAKING to bridge possible p->pi_lock to rq->lock gaps and serialize set_task_cpu() calls against task_rq_lock(). The p->pi_lock serialization of p->sched_class allows us to call scheduling class methods without holding the rq->lock, and the serialization of p->cpus_allowed allows us to do the load-balancing bits without races. Reviewed-by: Frank Rowand Cc: Mike Galbraith Cc: Nick Piggin Cc: Linus Torvalds Cc: Andrew Morton Signed-off-by: Ingo Molnar Signed-off-by: Peter Zijlstra Link: http://lkml.kernel.org/r/20110405152729.354401150@chello.nl --- kernel/sched.c | 65 +++++++++++++++++++++++++++++++++------------------------- 1 file changed, 37 insertions(+), 28 deletions(-) (limited to 'kernel') diff --git a/kernel/sched.c b/kernel/sched.c index 1be1a09..871dd9e 100644 --- a/kernel/sched.c +++ b/kernel/sched.c @@ -2493,69 +2493,78 @@ ttwu_post_activation(struct task_struct *p, struct rq *rq, int wake_flags) * Returns %true if @p was woken up, %false if it was already running * or @state didn't match @p's state. */ -static int try_to_wake_up(struct task_struct *p, unsigned int state, - int wake_flags) +static int +try_to_wake_up(struct task_struct *p, unsigned int state, int wake_flags) { - int cpu, orig_cpu, this_cpu, success = 0; + int cpu, this_cpu, success = 0; unsigned long flags; - unsigned long en_flags = ENQUEUE_WAKEUP; struct rq *rq; this_cpu = get_cpu(); smp_wmb(); raw_spin_lock_irqsave(&p->pi_lock, flags); - rq = __task_rq_lock(p); if (!(p->state & state)) goto out; cpu = task_cpu(p); - if (p->on_rq) - goto out_running; + if (p->on_rq) { + rq = __task_rq_lock(p); + if (p->on_rq) + goto out_running; + __task_rq_unlock(rq); + } - orig_cpu = cpu; #ifdef CONFIG_SMP - if (unlikely(task_running(rq, p))) - goto out_activate; + while (p->on_cpu) { +#ifdef __ARCH_WANT_INTERRUPTS_ON_CTXSW + /* + * If called from interrupt context we could have landed in the + * middle of schedule(), in this case we should take care not + * to spin on ->on_cpu if p is current, since that would + * deadlock. + */ + if (p == current) + goto out_activate; +#endif + cpu_relax(); + } + /* + * Pairs with the smp_wmb() in finish_lock_switch(). + */ + smp_rmb(); p->sched_contributes_to_load = !!task_contributes_to_load(p); p->state = TASK_WAKING; - if (p->sched_class->task_waking) { + if (p->sched_class->task_waking) p->sched_class->task_waking(p); - en_flags |= ENQUEUE_WAKING; - } cpu = select_task_rq(p, SD_BALANCE_WAKE, wake_flags); - if (cpu != orig_cpu) - set_task_cpu(p, cpu); - __task_rq_unlock(rq); +#ifdef __ARCH_WANT_INTERRUPTS_ON_CTXSW +out_activate: +#endif +#endif /* CONFIG_SMP */ rq = cpu_rq(cpu); raw_spin_lock(&rq->lock); - /* - * We migrated the task without holding either rq->lock, however - * since the task is not on the task list itself, nobody else - * will try and migrate the task, hence the rq should match the - * cpu we just moved it to. - */ - WARN_ON(task_cpu(p) != cpu); - WARN_ON(p->state != TASK_WAKING); +#ifdef CONFIG_SMP + if (cpu != task_cpu(p)) + set_task_cpu(p, cpu); if (p->sched_contributes_to_load) rq->nr_uninterruptible--; +#endif -out_activate: -#endif /* CONFIG_SMP */ - ttwu_activate(rq, p, en_flags); + ttwu_activate(rq, p, ENQUEUE_WAKEUP | ENQUEUE_WAKING); out_running: ttwu_post_activation(p, rq, wake_flags); ttwu_stat(rq, p, cpu, wake_flags); success = 1; -out: __task_rq_unlock(rq); +out: raw_spin_unlock_irqrestore(&p->pi_lock, flags); put_cpu(); -- cgit v1.1 From b84cb5df1f9ad6da3f214c638d5fb08d0c99de1f Mon Sep 17 00:00:00 2001 From: Peter Zijlstra Date: Tue, 5 Apr 2011 17:23:55 +0200 Subject: sched: Remove rq argument from ttwu_stat() In order to call ttwu_stat() without holding rq->lock we must remove its rq argument. Since we need to change rq stats, account to the local rq instead of the task rq, this is safe since we have IRQs disabled. Reviewed-by: Frank Rowand Cc: Mike Galbraith Cc: Nick Piggin Cc: Linus Torvalds Cc: Andrew Morton Signed-off-by: Ingo Molnar Signed-off-by: Peter Zijlstra Link: http://lkml.kernel.org/r/20110405152729.394638826@chello.nl --- kernel/sched.c | 9 ++++++--- 1 file changed, 6 insertions(+), 3 deletions(-) (limited to 'kernel') diff --git a/kernel/sched.c b/kernel/sched.c index 871dd9e..5ec2e8b 100644 --- a/kernel/sched.c +++ b/kernel/sched.c @@ -2410,9 +2410,11 @@ static void update_avg(u64 *avg, u64 sample) #endif static void -ttwu_stat(struct rq *rq, struct task_struct *p, int cpu, int wake_flags) +ttwu_stat(struct task_struct *p, int cpu, int wake_flags) { #ifdef CONFIG_SCHEDSTATS + struct rq *rq = this_rq(); + #ifdef CONFIG_SMP int this_cpu = smp_processor_id(); @@ -2561,9 +2563,10 @@ out_activate: ttwu_activate(rq, p, ENQUEUE_WAKEUP | ENQUEUE_WAKING); out_running: ttwu_post_activation(p, rq, wake_flags); - ttwu_stat(rq, p, cpu, wake_flags); success = 1; __task_rq_unlock(rq); + + ttwu_stat(p, cpu, wake_flags); out: raw_spin_unlock_irqrestore(&p->pi_lock, flags); put_cpu(); @@ -2600,7 +2603,7 @@ static void try_to_wake_up_local(struct task_struct *p) ttwu_activate(rq, p, ENQUEUE_WAKEUP); ttwu_post_activation(p, rq, 0); - ttwu_stat(rq, p, smp_processor_id(), 0); + ttwu_stat(p, smp_processor_id(), 0); out: raw_spin_unlock(&p->pi_lock); } -- cgit v1.1 From 23f41eeb42ce7f6f1210904e49e84718f02cb61c Mon Sep 17 00:00:00 2001 From: Peter Zijlstra Date: Tue, 5 Apr 2011 17:23:56 +0200 Subject: sched: Rename ttwu_post_activation() to ttwu_do_wakeup() The ttwu_post_activation() code does the core wakeup, it sets TASK_RUNNING and performs wakeup-preemption, so give is a more descriptive name. Reviewed-by: Frank Rowand Cc: Mike Galbraith Cc: Nick Piggin Cc: Linus Torvalds Cc: Andrew Morton Signed-off-by: Ingo Molnar Signed-off-by: Peter Zijlstra Link: http://lkml.kernel.org/r/20110405152729.434609705@chello.nl --- kernel/sched.c | 9 ++++++--- 1 file changed, 6 insertions(+), 3 deletions(-) (limited to 'kernel') diff --git a/kernel/sched.c b/kernel/sched.c index 5ec2e8b..e309dba 100644 --- a/kernel/sched.c +++ b/kernel/sched.c @@ -2456,8 +2456,11 @@ static void ttwu_activate(struct rq *rq, struct task_struct *p, int en_flags) wq_worker_waking_up(p, cpu_of(rq)); } +/* + * Mark the task runnable and perform wakeup-preemption. + */ static void -ttwu_post_activation(struct task_struct *p, struct rq *rq, int wake_flags) +ttwu_do_wakeup(struct rq *rq, struct task_struct *p, int wake_flags) { trace_sched_wakeup(p, true); check_preempt_curr(rq, p, wake_flags); @@ -2562,7 +2565,7 @@ out_activate: ttwu_activate(rq, p, ENQUEUE_WAKEUP | ENQUEUE_WAKING); out_running: - ttwu_post_activation(p, rq, wake_flags); + ttwu_do_wakeup(rq, p, wake_flags); success = 1; __task_rq_unlock(rq); @@ -2602,7 +2605,7 @@ static void try_to_wake_up_local(struct task_struct *p) if (!p->on_rq) ttwu_activate(rq, p, ENQUEUE_WAKEUP); - ttwu_post_activation(p, rq, 0); + ttwu_do_wakeup(rq, p, 0); ttwu_stat(p, smp_processor_id(), 0); out: raw_spin_unlock(&p->pi_lock); -- cgit v1.1 From c05fbafba1c5482bee399b360288fa405415e126 Mon Sep 17 00:00:00 2001 From: Peter Zijlstra Date: Tue, 5 Apr 2011 17:23:57 +0200 Subject: sched: Restructure ttwu() some more Factor our helper functions to make the inner workings of try_to_wake_up() more obvious, this also allows for adding remote queues. Reviewed-by: Frank Rowand Cc: Mike Galbraith Cc: Nick Piggin Cc: Linus Torvalds Cc: Andrew Morton Signed-off-by: Ingo Molnar Signed-off-by: Peter Zijlstra Link: http://lkml.kernel.org/r/20110405152729.475848012@chello.nl --- kernel/sched.c | 91 +++++++++++++++++++++++++++++++++++++--------------------- 1 file changed, 58 insertions(+), 33 deletions(-) (limited to 'kernel') diff --git a/kernel/sched.c b/kernel/sched.c index e309dba..7d8b85f 100644 --- a/kernel/sched.c +++ b/kernel/sched.c @@ -2483,6 +2483,48 @@ ttwu_do_wakeup(struct rq *rq, struct task_struct *p, int wake_flags) #endif } +static void +ttwu_do_activate(struct rq *rq, struct task_struct *p, int wake_flags) +{ +#ifdef CONFIG_SMP + if (p->sched_contributes_to_load) + rq->nr_uninterruptible--; +#endif + + ttwu_activate(rq, p, ENQUEUE_WAKEUP | ENQUEUE_WAKING); + ttwu_do_wakeup(rq, p, wake_flags); +} + +/* + * Called in case the task @p isn't fully descheduled from its runqueue, + * in this case we must do a remote wakeup. Its a 'light' wakeup though, + * since all we need to do is flip p->state to TASK_RUNNING, since + * the task is still ->on_rq. + */ +static int ttwu_remote(struct task_struct *p, int wake_flags) +{ + struct rq *rq; + int ret = 0; + + rq = __task_rq_lock(p); + if (p->on_rq) { + ttwu_do_wakeup(rq, p, wake_flags); + ret = 1; + } + __task_rq_unlock(rq); + + return ret; +} + +static void ttwu_queue(struct task_struct *p, int cpu) +{ + struct rq *rq = cpu_rq(cpu); + + raw_spin_lock(&rq->lock); + ttwu_do_activate(rq, p, 0); + raw_spin_unlock(&rq->lock); +} + /** * try_to_wake_up - wake up a thread * @p: the thread to be awakened @@ -2501,27 +2543,25 @@ ttwu_do_wakeup(struct rq *rq, struct task_struct *p, int wake_flags) static int try_to_wake_up(struct task_struct *p, unsigned int state, int wake_flags) { - int cpu, this_cpu, success = 0; unsigned long flags; - struct rq *rq; - - this_cpu = get_cpu(); + int cpu, success = 0; smp_wmb(); raw_spin_lock_irqsave(&p->pi_lock, flags); if (!(p->state & state)) goto out; + success = 1; /* we're going to change ->state */ cpu = task_cpu(p); - if (p->on_rq) { - rq = __task_rq_lock(p); - if (p->on_rq) - goto out_running; - __task_rq_unlock(rq); - } + if (p->on_rq && ttwu_remote(p, wake_flags)) + goto stat; #ifdef CONFIG_SMP + /* + * If the owning (remote) cpu is still in the middle of schedule() with + * this task as prev, wait until its done referencing the task. + */ while (p->on_cpu) { #ifdef __ARCH_WANT_INTERRUPTS_ON_CTXSW /* @@ -2530,8 +2570,10 @@ try_to_wake_up(struct task_struct *p, unsigned int state, int wake_flags) * to spin on ->on_cpu if p is current, since that would * deadlock. */ - if (p == current) - goto out_activate; + if (p == current) { + ttwu_queue(p, cpu); + goto stat; + } #endif cpu_relax(); } @@ -2547,32 +2589,15 @@ try_to_wake_up(struct task_struct *p, unsigned int state, int wake_flags) p->sched_class->task_waking(p); cpu = select_task_rq(p, SD_BALANCE_WAKE, wake_flags); -#ifdef __ARCH_WANT_INTERRUPTS_ON_CTXSW -out_activate: -#endif -#endif /* CONFIG_SMP */ - - rq = cpu_rq(cpu); - raw_spin_lock(&rq->lock); - -#ifdef CONFIG_SMP - if (cpu != task_cpu(p)) + if (task_cpu(p) != cpu) set_task_cpu(p, cpu); +#endif /* CONFIG_SMP */ - if (p->sched_contributes_to_load) - rq->nr_uninterruptible--; -#endif - - ttwu_activate(rq, p, ENQUEUE_WAKEUP | ENQUEUE_WAKING); -out_running: - ttwu_do_wakeup(rq, p, wake_flags); - success = 1; - __task_rq_unlock(rq); - + ttwu_queue(p, cpu); +stat: ttwu_stat(p, cpu, wake_flags); out: raw_spin_unlock_irqrestore(&p->pi_lock, flags); - put_cpu(); return success; } -- cgit v1.1 From 317f394160e9beb97d19a84c39b7e5eb3d7815a8 Mon Sep 17 00:00:00 2001 From: Peter Zijlstra Date: Tue, 5 Apr 2011 17:23:58 +0200 Subject: sched: Move the second half of ttwu() to the remote cpu Now that we've removed the rq->lock requirement from the first part of ttwu() and can compute placement without holding any rq->lock, ensure we execute the second half of ttwu() on the actual cpu we want the task to run on. This avoids having to take rq->lock and doing the task enqueue remotely, saving lots on cacheline transfers. As measured using: http://oss.oracle.com/~mason/sembench.c $ for i in /sys/devices/system/cpu/cpu*/cpufreq/scaling_governor ; do echo performance > $i; done $ echo 4096 32000 64 128 > /proc/sys/kernel/sem $ ./sembench -t 2048 -w 1900 -o 0 unpatched: run time 30 seconds 647278 worker burns per second patched: run time 30 seconds 816715 worker burns per second Reviewed-by: Frank Rowand Cc: Mike Galbraith Cc: Nick Piggin Cc: Linus Torvalds Cc: Andrew Morton Signed-off-by: Ingo Molnar Signed-off-by: Peter Zijlstra Link: http://lkml.kernel.org/r/20110405152729.515897185@chello.nl --- kernel/sched.c | 56 +++++++++++++++++++++++++++++++++++++++++++++++++ kernel/sched_features.h | 6 ++++++ 2 files changed, 62 insertions(+) (limited to 'kernel') diff --git a/kernel/sched.c b/kernel/sched.c index 7d8b85f..9e3ede1 100644 --- a/kernel/sched.c +++ b/kernel/sched.c @@ -556,6 +556,10 @@ struct rq { unsigned int ttwu_count; unsigned int ttwu_local; #endif + +#ifdef CONFIG_SMP + struct task_struct *wake_list; +#endif }; static DEFINE_PER_CPU_SHARED_ALIGNED(struct rq, runqueues); @@ -2516,10 +2520,61 @@ static int ttwu_remote(struct task_struct *p, int wake_flags) return ret; } +#ifdef CONFIG_SMP +static void sched_ttwu_pending(void) +{ + struct rq *rq = this_rq(); + struct task_struct *list = xchg(&rq->wake_list, NULL); + + if (!list) + return; + + raw_spin_lock(&rq->lock); + + while (list) { + struct task_struct *p = list; + list = list->wake_entry; + ttwu_do_activate(rq, p, 0); + } + + raw_spin_unlock(&rq->lock); +} + +void scheduler_ipi(void) +{ + sched_ttwu_pending(); +} + +static void ttwu_queue_remote(struct task_struct *p, int cpu) +{ + struct rq *rq = cpu_rq(cpu); + struct task_struct *next = rq->wake_list; + + for (;;) { + struct task_struct *old = next; + + p->wake_entry = next; + next = cmpxchg(&rq->wake_list, old, p); + if (next == old) + break; + } + + if (!next) + smp_send_reschedule(cpu); +} +#endif + static void ttwu_queue(struct task_struct *p, int cpu) { struct rq *rq = cpu_rq(cpu); +#if defined(CONFIG_SMP) && defined(CONFIG_SCHED_TTWU_QUEUE) + if (sched_feat(TTWU_QUEUE) && cpu != smp_processor_id()) { + ttwu_queue_remote(p, cpu); + return; + } +#endif + raw_spin_lock(&rq->lock); ttwu_do_activate(rq, p, 0); raw_spin_unlock(&rq->lock); @@ -6331,6 +6386,7 @@ migration_call(struct notifier_block *nfb, unsigned long action, void *hcpu) #ifdef CONFIG_HOTPLUG_CPU case CPU_DYING: + sched_ttwu_pending(); /* Update our root-domain */ raw_spin_lock_irqsave(&rq->lock, flags); if (rq->rd) { diff --git a/kernel/sched_features.h b/kernel/sched_features.h index 68e69ac..be40f73 100644 --- a/kernel/sched_features.h +++ b/kernel/sched_features.h @@ -64,3 +64,9 @@ SCHED_FEAT(OWNER_SPIN, 1) * Decrement CPU power based on irq activity */ SCHED_FEAT(NONIRQ_POWER, 1) + +/* + * Queue remote wakeups on the target CPU and process them + * using the scheduler IPI. Reduces rq->lock contention/bounces. + */ +SCHED_FEAT(TTWU_QUEUE, 1) -- cgit v1.1 From bd8e7dded88a3e1c085c333f19ff31387616f71a Mon Sep 17 00:00:00 2001 From: Peter Zijlstra Date: Tue, 5 Apr 2011 17:23:59 +0200 Subject: sched: Remove need_migrate_task() Oleg noticed that need_migrate_task() doesn't need the ->on_cpu check now that ttwu() doesn't do remote enqueues for !->on_rq && ->on_cpu, so remove the helper and replace the single instance with a direct ->on_rq test. Suggested-by: Oleg Nesterov Reviewed-by: Frank Rowand Signed-off-by: Peter Zijlstra Cc: Mike Galbraith Cc: Nick Piggin Cc: Linus Torvalds Cc: Andrew Morton Link: http://lkml.kernel.org/r/20110405152729.556674812@chello.nl Signed-off-by: Ingo Molnar --- kernel/sched.c | 17 +---------------- 1 file changed, 1 insertion(+), 16 deletions(-) (limited to 'kernel') diff --git a/kernel/sched.c b/kernel/sched.c index 9e3ede1..cd597c7 100644 --- a/kernel/sched.c +++ b/kernel/sched.c @@ -2199,21 +2199,6 @@ struct migration_arg { static int migration_cpu_stop(void *data); /* - * The task's runqueue lock must be held. - * Returns true if you have to wait for migration thread. - */ -static bool need_migrate_task(struct task_struct *p) -{ - /* - * If the task is not on a runqueue (and not running), then - * the next wake-up will properly place the task. - */ - bool running = p->on_rq || p->on_cpu; - smp_rmb(); /* finish_lock_switch() */ - return running; -} - -/* * wait_task_inactive - wait for a thread to unschedule. * * If @match_state is nonzero, it's the @p->state value just checked and @@ -5985,7 +5970,7 @@ int set_cpus_allowed_ptr(struct task_struct *p, const struct cpumask *new_mask) goto out; dest_cpu = cpumask_any_and(cpu_active_mask, new_mask); - if (need_migrate_task(p)) { + if (p->on_rq) { struct migration_arg arg = { p, dest_cpu }; /* Need help from migration thread: drop lock and wait. */ task_rq_unlock(rq, p, &flags); -- cgit v1.1 From 69c80f3e9d3c569f8a3cee94ba1a324b5a7fa6b9 Mon Sep 17 00:00:00 2001 From: Venkatesh Pallipadi Date: Wed, 13 Apr 2011 18:21:09 -0700 Subject: sched: Make set_*_buddy() work on non-task entities Make set_*_buddy() work on non-task sched_entity, to facilitate the use of next_buddy to cache a group entity in cases where one of the tasks within that entity sleeps or gets preempted. set_skip_buddy() was incorrectly comparing the policy of task that is yielding to be not equal to SCHED_IDLE. Yielding should happen even when task yielding is SCHED_IDLE. This change removes the policy check on the yielding task. Signed-off-by: Venkatesh Pallipadi Signed-off-by: Peter Zijlstra Link: http://lkml.kernel.org/r/1302744070-30079-2-git-send-email-venki@google.com Signed-off-by: Ingo Molnar --- kernel/sched_fair.c | 24 ++++++++++++------------ 1 file changed, 12 insertions(+), 12 deletions(-) (limited to 'kernel') diff --git a/kernel/sched_fair.c b/kernel/sched_fair.c index 8744593..501ab63 100644 --- a/kernel/sched_fair.c +++ b/kernel/sched_fair.c @@ -1846,26 +1846,26 @@ wakeup_preempt_entity(struct sched_entity *curr, struct sched_entity *se) static void set_last_buddy(struct sched_entity *se) { - if (likely(task_of(se)->policy != SCHED_IDLE)) { - for_each_sched_entity(se) - cfs_rq_of(se)->last = se; - } + if (entity_is_task(se) && unlikely(task_of(se)->policy == SCHED_IDLE)) + return; + + for_each_sched_entity(se) + cfs_rq_of(se)->last = se; } static void set_next_buddy(struct sched_entity *se) { - if (likely(task_of(se)->policy != SCHED_IDLE)) { - for_each_sched_entity(se) - cfs_rq_of(se)->next = se; - } + if (entity_is_task(se) && unlikely(task_of(se)->policy == SCHED_IDLE)) + return; + + for_each_sched_entity(se) + cfs_rq_of(se)->next = se; } static void set_skip_buddy(struct sched_entity *se) { - if (likely(task_of(se)->policy != SCHED_IDLE)) { - for_each_sched_entity(se) - cfs_rq_of(se)->skip = se; - } + for_each_sched_entity(se) + cfs_rq_of(se)->skip = se; } /* -- cgit v1.1 From 2f36825b176f67e5c5228aa33d828bc39718811f Mon Sep 17 00:00:00 2001 From: Venkatesh Pallipadi Date: Thu, 14 Apr 2011 10:30:53 -0700 Subject: sched: Next buddy hint on sleep and preempt path When a task in a taskgroup sleeps, pick_next_task starts all the way back at the root and picks the task/taskgroup with the min vruntime across all runnable tasks. But when there are many frequently sleeping tasks across different taskgroups, it makes better sense to stay with same taskgroup for its slice period (or until all tasks in the taskgroup sleeps) instead of switching cross taskgroup on each sleep after a short runtime. This helps specifically where taskgroups corresponds to a process with multiple threads. The change reduces the number of CR3 switches in this case. Example: Two taskgroups with 2 threads each which are running for 2ms and sleeping for 1ms. Looking at sched:sched_switch shows: BEFORE: taskgroup_1 threads [5004, 5005], taskgroup_2 threads [5016, 5017] cpu-soaker-5004 [003] 3683.391089 cpu-soaker-5016 [003] 3683.393106 cpu-soaker-5005 [003] 3683.395119 cpu-soaker-5017 [003] 3683.397130 cpu-soaker-5004 [003] 3683.399143 cpu-soaker-5016 [003] 3683.401155 cpu-soaker-5005 [003] 3683.403168 cpu-soaker-5017 [003] 3683.405170 AFTER: taskgroup_1 threads [21890, 21891], taskgroup_2 threads [21934, 21935] cpu-soaker-21890 [003] 865.895494 cpu-soaker-21935 [003] 865.897506 cpu-soaker-21934 [003] 865.899520 cpu-soaker-21935 [003] 865.901532 cpu-soaker-21934 [003] 865.903543 cpu-soaker-21935 [003] 865.905546 cpu-soaker-21891 [003] 865.907548 cpu-soaker-21890 [003] 865.909560 cpu-soaker-21891 [003] 865.911571 cpu-soaker-21890 [003] 865.913582 cpu-soaker-21891 [003] 865.915594 cpu-soaker-21934 [003] 865.917606 Similar problem is there when there are multiple taskgroups and say a task A preempts currently running task B of taskgroup_1. On schedule, pick_next_task can pick an unrelated task on taskgroup_2. Here it would be better to give some preference to task B on pick_next_task. A simple (may be extreme case) benchmark I tried was tbench with 2 tbench client processes with 2 threads each running on a single CPU. Avg throughput across 5 50 sec runs was: BEFORE: 105.84 MB/sec AFTER: 112.42 MB/sec Signed-off-by: Venkatesh Pallipadi Acked-by: Rik van Riel Signed-off-by: Peter Zijlstra Link: http://lkml.kernel.org/r/1302802253-25760-1-git-send-email-venki@google.com Signed-off-by: Ingo Molnar --- kernel/sched_fair.c | 26 +++++++++++++++++++++++--- 1 file changed, 23 insertions(+), 3 deletions(-) (limited to 'kernel') diff --git a/kernel/sched_fair.c b/kernel/sched_fair.c index 501ab63..5280272 100644 --- a/kernel/sched_fair.c +++ b/kernel/sched_fair.c @@ -1344,6 +1344,8 @@ enqueue_task_fair(struct rq *rq, struct task_struct *p, int flags) hrtick_update(rq); } +static void set_next_buddy(struct sched_entity *se); + /* * The dequeue_task method is called before nr_running is * decreased. We remove the task from the rbtree and @@ -1353,14 +1355,22 @@ static void dequeue_task_fair(struct rq *rq, struct task_struct *p, int flags) { struct cfs_rq *cfs_rq; struct sched_entity *se = &p->se; + int task_sleep = flags & DEQUEUE_SLEEP; for_each_sched_entity(se) { cfs_rq = cfs_rq_of(se); dequeue_entity(cfs_rq, se, flags); /* Don't dequeue parent if it has other entities besides us */ - if (cfs_rq->load.weight) + if (cfs_rq->load.weight) { + /* + * Bias pick_next to pick a task from this cfs_rq, as + * p is sleeping when it is within its sched_slice. + */ + if (task_sleep && parent_entity(se)) + set_next_buddy(parent_entity(se)); break; + } flags |= DEQUEUE_SLEEP; } @@ -1877,12 +1887,15 @@ static void check_preempt_wakeup(struct rq *rq, struct task_struct *p, int wake_ struct sched_entity *se = &curr->se, *pse = &p->se; struct cfs_rq *cfs_rq = task_cfs_rq(curr); int scale = cfs_rq->nr_running >= sched_nr_latency; + int next_buddy_marked = 0; if (unlikely(se == pse)) return; - if (sched_feat(NEXT_BUDDY) && scale && !(wake_flags & WF_FORK)) + if (sched_feat(NEXT_BUDDY) && scale && !(wake_flags & WF_FORK)) { set_next_buddy(pse); + next_buddy_marked = 1; + } /* * We can come here with TIF_NEED_RESCHED already set from new task @@ -1910,8 +1923,15 @@ static void check_preempt_wakeup(struct rq *rq, struct task_struct *p, int wake_ update_curr(cfs_rq); find_matching_se(&se, &pse); BUG_ON(!pse); - if (wakeup_preempt_entity(se, pse) == 1) + if (wakeup_preempt_entity(se, pse) == 1) { + /* + * Bias pick_next to pick the sched entity that is + * triggering this preemption. + */ + if (!next_buddy_marked) + set_next_buddy(pse); goto preempt; + } return; -- cgit v1.1 From 057f3fadb347e9c51b07e1b277bbdda79f976768 Mon Sep 17 00:00:00 2001 From: Peter Zijlstra Date: Mon, 18 Apr 2011 11:24:34 +0200 Subject: sched: Fix sched_domain iterations vs. RCU Vladis Kletnieks reported a new RCU debug warning in the scheduler. Since commit dce840a08702b ("sched: Dynamically allocate sched_domain/ sched_group data-structures") the sched_domain trees are protected by RCU instead of RCU-sched. This means that we need to include rcu_read_lock() protection when we iterate them since disabling preemption doesn't suffice anymore. Reported-by: Valdis.Kletnieks@vt.edu Signed-off-by: Peter Zijlstra Link: http://lkml.kernel.org/r/1302882741.2388.241.camel@twins Signed-off-by: Ingo Molnar --- kernel/sched.c | 14 +++++++++++--- 1 file changed, 11 insertions(+), 3 deletions(-) (limited to 'kernel') diff --git a/kernel/sched.c b/kernel/sched.c index 0cfe031..27d3e73 100644 --- a/kernel/sched.c +++ b/kernel/sched.c @@ -1208,11 +1208,17 @@ int get_nohz_timer_target(void) int i; struct sched_domain *sd; + rcu_read_lock(); for_each_domain(cpu, sd) { - for_each_cpu(i, sched_domain_span(sd)) - if (!idle_cpu(i)) - return i; + for_each_cpu(i, sched_domain_span(sd)) { + if (!idle_cpu(i)) { + cpu = i; + goto unlock; + } + } } +unlock: + rcu_read_unlock(); return cpu; } /* @@ -2415,12 +2421,14 @@ ttwu_stat(struct task_struct *p, int cpu, int wake_flags) struct sched_domain *sd; schedstat_inc(p, se.statistics.nr_wakeups_remote); + rcu_read_lock(); for_each_domain(this_cpu, sd) { if (cpumask_test_cpu(cpu, sched_domain_span(sd))) { schedstat_inc(sd, ttwu_wake_remote); break; } } + rcu_read_unlock(); } #endif /* CONFIG_SMP */ -- cgit v1.1 From 088ab0b4d855d68a0f0c16b72fb8e492a533aaa1 Mon Sep 17 00:00:00 2001 From: Ludwig Nussel Date: Mon, 28 Feb 2011 15:57:17 +0100 Subject: kernel/ksysfs.c: expose file_caps_enabled in sysfs A kernel booted with no_file_caps allows to install fscaps on a binary but doesn't actually honor the fscaps when running the binary. Userspace currently has no sane way to determine whether installing fscaps actually has any effect. Since parsing /proc/cmdline is fragile this patch exposes the current setting (1 or 0) via /sys/kernel/fscaps Signed-off-by: Ludwig Nussel Signed-off-by: Greg Kroah-Hartman --- kernel/ksysfs.c | 10 ++++++++++ 1 file changed, 10 insertions(+) (limited to 'kernel') diff --git a/kernel/ksysfs.c b/kernel/ksysfs.c index 0b624e7..3b053c0 100644 --- a/kernel/ksysfs.c +++ b/kernel/ksysfs.c @@ -16,6 +16,7 @@ #include #include #include +#include #define KERNEL_ATTR_RO(_name) \ static struct kobj_attribute _name##_attr = __ATTR_RO(_name) @@ -131,6 +132,14 @@ KERNEL_ATTR_RO(vmcoreinfo); #endif /* CONFIG_KEXEC */ +/* whether file capabilities are enabled */ +static ssize_t fscaps_show(struct kobject *kobj, + struct kobj_attribute *attr, char *buf) +{ + return sprintf(buf, "%d\n", file_caps_enabled); +} +KERNEL_ATTR_RO(fscaps); + /* * Make /sys/kernel/notes give the raw contents of our kernel .notes section. */ @@ -158,6 +167,7 @@ struct kobject *kernel_kobj; EXPORT_SYMBOL_GPL(kernel_kobj); static struct attribute * kernel_attrs[] = { + &fscaps_attr.attr, #if defined(CONFIG_HOTPLUG) &uevent_seqnum_attr.attr, &uevent_helper_attr.attr, -- cgit v1.1 From d3bf52e998056a6002b2aecfe1d25486376382ac Mon Sep 17 00:00:00 2001 From: Rakib Mullick Date: Wed, 20 Apr 2011 21:27:32 +0600 Subject: sched: Remove obsolete comment from scheduler_tick() scheduler_tick() is no longer called by fork code - this got discarded a long time ago by commit bc947631d1d532 ("sched: improve efficiency of sched_fork()"). So, remove the comment which still claims otherwise. Signed-off-by: Rakib Mullick Cc: Peter Zijlstra Link: http://lkml.kernel.org/r/BANLkTimO4iGP0QpaHO1HHF1QOnVcQpc0cw@mail.gmail.com Signed-off-by: Ingo Molnar --- kernel/sched.c | 3 --- 1 file changed, 3 deletions(-) (limited to 'kernel') diff --git a/kernel/sched.c b/kernel/sched.c index 30a29ad..8cb0a57 100644 --- a/kernel/sched.c +++ b/kernel/sched.c @@ -4002,9 +4002,6 @@ void thread_group_times(struct task_struct *p, cputime_t *ut, cputime_t *st) /* * This function gets called by the timer code, with HZ frequency. * We call it with interrupts disabled. - * - * It also gets called by the fork code, when changing the parent's - * timeslices. */ void scheduler_tick(void) { -- cgit v1.1 From 3003eba313dd0e0502dd71548c36fe7c19801ce5 Mon Sep 17 00:00:00 2001 From: Steven Rostedt Date: Wed, 20 Apr 2011 21:41:54 -0400 Subject: lockdep: Print a nicer description for irq lock inversions Locking order inversion due to interrupts is a subtle problem. When an irq lockiinversion discovered by lockdep it currently reports something like: [ INFO: HARDIRQ-safe -> HARDIRQ-unsafe lock order detected ] ... and then prints out the locks that are involved, as back traces. Judging by lkml feedback developers were routinely confused by what a HARDIRQ->safe to unsafe issue is all about, and sometimes even blew it off as a bug in lockdep. It is not obvious when lockdep prints this message about a lock that is never taken in interrupt context. After explaining the problems that lockdep is reporting, I decided to add a description of the problem in visual form. Now the following is shown: --- other info that might help us debug this: Possible interrupt unsafe locking scenario: CPU0 CPU1 ---- ---- lock(lockA); local_irq_disable(); lock(&rq->lock); lock(lockA); lock(&rq->lock); *** DEADLOCK *** --- The above is the case when the unsafe lock is taken while holding a lock taken in irq context. But when a lock is taken that also grabs a unsafe lock, the call chain is shown: --- other info that might help us debug this: Chain exists of: &rq->lock --> lockA --> lockC Possible interrupt unsafe locking scenario: CPU0 CPU1 ---- ---- lock(lockC); local_irq_disable(); lock(&rq->lock); lock(lockA); lock(&rq->lock); *** DEADLOCK *** Signed-off-by: Steven Rostedt Acked-by: Peter Zijlstra Cc: Frederic Weisbecker Cc: Linus Torvalds Cc: Andrew Morton Link: http://lkml.kernel.org/r/20110421014259.132728798@goodmis.org Signed-off-by: Ingo Molnar --- kernel/lockdep.c | 70 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 70 insertions(+) (limited to 'kernel') diff --git a/kernel/lockdep.c b/kernel/lockdep.c index 53a6895..7b2ffee 100644 --- a/kernel/lockdep.c +++ b/kernel/lockdep.c @@ -490,6 +490,18 @@ void get_usage_chars(struct lock_class *class, char usage[LOCK_USAGE_CHARS]) usage[i] = '\0'; } +static int __print_lock_name(struct lock_class *class) +{ + char str[KSYM_NAME_LEN]; + const char *name; + + name = class->name; + if (!name) + name = __get_key_name(class->key, str); + + return printk("%s", name); +} + static void print_lock_name(struct lock_class *class) { char str[KSYM_NAME_LEN], usage[LOCK_USAGE_CHARS]; @@ -1325,6 +1337,62 @@ print_shortest_lock_dependencies(struct lock_list *leaf, return; } +static void +print_irq_lock_scenario(struct lock_list *safe_entry, + struct lock_list *unsafe_entry, + struct held_lock *prev, + struct held_lock *next) +{ + struct lock_class *safe_class = safe_entry->class; + struct lock_class *unsafe_class = unsafe_entry->class; + struct lock_class *middle_class = hlock_class(prev); + + if (middle_class == safe_class) + middle_class = hlock_class(next); + + /* + * A direct locking problem where unsafe_class lock is taken + * directly by safe_class lock, then all we need to show + * is the deadlock scenario, as it is obvious that the + * unsafe lock is taken under the safe lock. + * + * But if there is a chain instead, where the safe lock takes + * an intermediate lock (middle_class) where this lock is + * not the same as the safe lock, then the lock chain is + * used to describe the problem. Otherwise we would need + * to show a different CPU case for each link in the chain + * from the safe_class lock to the unsafe_class lock. + */ + if (middle_class != unsafe_class) { + printk("Chain exists of:\n "); + __print_lock_name(safe_class); + printk(" --> "); + __print_lock_name(middle_class); + printk(" --> "); + __print_lock_name(unsafe_class); + printk("\n\n"); + } + + printk(" Possible interrupt unsafe locking scenario:\n\n"); + printk(" CPU0 CPU1\n"); + printk(" ---- ----\n"); + printk(" lock("); + __print_lock_name(unsafe_class); + printk(");\n"); + printk(" local_irq_disable();\n"); + printk(" lock("); + __print_lock_name(safe_class); + printk(");\n"); + printk(" lock("); + __print_lock_name(middle_class); + printk(");\n"); + printk(" \n"); + printk(" lock("); + __print_lock_name(safe_class); + printk(");\n"); + printk("\n *** DEADLOCK ***\n\n"); +} + static int print_bad_irq_dependency(struct task_struct *curr, struct lock_list *prev_root, @@ -1376,6 +1444,8 @@ print_bad_irq_dependency(struct task_struct *curr, print_stack_trace(forwards_entry->class->usage_traces + bit2, 1); printk("\nother info that might help us debug this:\n\n"); + print_irq_lock_scenario(backwards_entry, forwards_entry, prev, next); + lockdep_print_held_locks(curr); printk("\nthe dependencies between %s-irq-safe lock", irqclass); -- cgit v1.1 From f4185812aa046ecb97e8817e10148cacdd7a6baa Mon Sep 17 00:00:00 2001 From: Steven Rostedt Date: Wed, 20 Apr 2011 21:41:55 -0400 Subject: lockdep: Print a nicer description for normal deadlocks The lockdep output can be pretty cryptic, having nicer output can save a lot of head scratching. When a normal deadlock scenario is detected by lockdep (lock A -> lock B and there exists a place where lock B -> lock A) we now get the following new output: other info that might help us debug this: Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(lockB); lock(lockA); lock(lockB); lock(lockA); *** DEADLOCK *** On cases where there's a deeper chair, it shows the partial chain that can cause the issue: Chain exists of: lockC --> lockA --> lockB Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(lockB); lock(lockA); lock(lockB); lock(lockC); *** DEADLOCK *** Signed-off-by: Steven Rostedt Acked-by: Peter Zijlstra Cc: Frederic Weisbecker Cc: Linus Torvalds Cc: Andrew Morton Link: http://lkml.kernel.org/r/20110421014259.380621789@goodmis.org Signed-off-by: Ingo Molnar --- kernel/lockdep.c | 55 +++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 55 insertions(+) (limited to 'kernel') diff --git a/kernel/lockdep.c b/kernel/lockdep.c index 7b2ffee..73cebd7 100644 --- a/kernel/lockdep.c +++ b/kernel/lockdep.c @@ -1065,6 +1065,56 @@ print_circular_bug_entry(struct lock_list *target, int depth) return 0; } +static void +print_circular_lock_scenario(struct held_lock *src, + struct held_lock *tgt, + struct lock_list *prt) +{ + struct lock_class *source = hlock_class(src); + struct lock_class *target = hlock_class(tgt); + struct lock_class *parent = prt->class; + + /* + * A direct locking problem where unsafe_class lock is taken + * directly by safe_class lock, then all we need to show + * is the deadlock scenario, as it is obvious that the + * unsafe lock is taken under the safe lock. + * + * But if there is a chain instead, where the safe lock takes + * an intermediate lock (middle_class) where this lock is + * not the same as the safe lock, then the lock chain is + * used to describe the problem. Otherwise we would need + * to show a different CPU case for each link in the chain + * from the safe_class lock to the unsafe_class lock. + */ + if (parent != source) { + printk("Chain exists of:\n "); + __print_lock_name(source); + printk(" --> "); + __print_lock_name(parent); + printk(" --> "); + __print_lock_name(target); + printk("\n\n"); + } + + printk(" Possible unsafe locking scenario:\n\n"); + printk(" CPU0 CPU1\n"); + printk(" ---- ----\n"); + printk(" lock("); + __print_lock_name(target); + printk(");\n"); + printk(" lock("); + __print_lock_name(parent); + printk(");\n"); + printk(" lock("); + __print_lock_name(target); + printk(");\n"); + printk(" lock("); + __print_lock_name(source); + printk(");\n"); + printk("\n *** DEADLOCK ***\n\n"); +} + /* * When a circular dependency is detected, print the * header first: @@ -1108,6 +1158,7 @@ static noinline int print_circular_bug(struct lock_list *this, { struct task_struct *curr = current; struct lock_list *parent; + struct lock_list *first_parent; int depth; if (!debug_locks_off_graph_unlock() || debug_locks_silent) @@ -1121,6 +1172,7 @@ static noinline int print_circular_bug(struct lock_list *this, print_circular_bug_header(target, depth, check_src, check_tgt); parent = get_lock_parent(target); + first_parent = parent; while (parent) { print_circular_bug_entry(parent, --depth); @@ -1128,6 +1180,9 @@ static noinline int print_circular_bug(struct lock_list *this, } printk("\nother info that might help us debug this:\n\n"); + print_circular_lock_scenario(check_src, check_tgt, + first_parent); + lockdep_print_held_locks(curr); printk("\nstack backtrace:\n"); -- cgit v1.1 From 48702ecf308e53f176c1f6fdc193d622ded54ac0 Mon Sep 17 00:00:00 2001 From: Steven Rostedt Date: Wed, 20 Apr 2011 21:41:56 -0400 Subject: lockdep: Print a nicer description for simple deadlocks Lockdep output can be pretty cryptic, having nicer output can save a lot of head scratching. When a simple deadlock scenario is detected by lockdep (lock A -> lock A) we now get the following new output: other info that might help us debug this: Possible unsafe locking scenario: CPU0 ---- lock(&(lock)->rlock); lock(&(lock)->rlock); *** DEADLOCK *** Signed-off-by: Steven Rostedt Acked-by: Peter Zijlstra Cc: Frederic Weisbecker Cc: Linus Torvalds Cc: Andrew Morton Link: http://lkml.kernel.org/r/20110421014259.643930104@goodmis.org Signed-off-by: Ingo Molnar --- kernel/lockdep.c | 21 +++++++++++++++++++++ 1 file changed, 21 insertions(+) (limited to 'kernel') diff --git a/kernel/lockdep.c b/kernel/lockdep.c index 73cebd7..c4cc5d1 100644 --- a/kernel/lockdep.c +++ b/kernel/lockdep.c @@ -1664,6 +1664,26 @@ static inline void inc_chains(void) #endif +static void +print_deadlock_scenario(struct held_lock *nxt, + struct held_lock *prv) +{ + struct lock_class *next = hlock_class(nxt); + struct lock_class *prev = hlock_class(prv); + + printk(" Possible unsafe locking scenario:\n\n"); + printk(" CPU0\n"); + printk(" ----\n"); + printk(" lock("); + __print_lock_name(prev); + printk(");\n"); + printk(" lock("); + __print_lock_name(next); + printk(");\n"); + printk("\n *** DEADLOCK ***\n\n"); + printk(" May be due to missing lock nesting notation\n\n"); +} + static int print_deadlock_bug(struct task_struct *curr, struct held_lock *prev, struct held_lock *next) @@ -1682,6 +1702,7 @@ print_deadlock_bug(struct task_struct *curr, struct held_lock *prev, print_lock(prev); printk("\nother info that might help us debug this:\n"); + print_deadlock_scenario(next, prev); lockdep_print_held_locks(curr); printk("\nstack backtrace:\n"); -- cgit v1.1 From dad3d7435e1d8c254d6877dc06852dc00c5da812 Mon Sep 17 00:00:00 2001 From: Steven Rostedt Date: Wed, 20 Apr 2011 21:41:57 -0400 Subject: lockdep: Print a nicer description for irq inversion bugs Irq inversion and irq dependency bugs are only subtly different. The diffenerence lies where the interrupt occurred. For irq dependency: irq_disable lock(A) lock(B) unlock(B) unlock(A) irq_enable lock(B) unlock(B) lock(A) The interrupt comes in after it has been established that lock A can be held when taking an irq unsafe lock. Lockdep detects the problem when taking lock A in interrupt context. With the irq_inversion the irq happens before it is established and lockdep detects the problem with the taking of lock B: lock(A) irq_disable lock(A) lock(B) unlock(B) unlock(A) irq_enable lock(B) unlock(B) Since the problem with the locking logic for both of these issues is in actuality the same, they both should report the same scenario. This patch implements that and prints this: other info that might help us debug this: Chain exists of: &rq->lock --> lockA --> lockC Possible interrupt unsafe locking scenario: CPU0 CPU1 ---- ---- lock(lockC); local_irq_disable(); lock(&rq->lock); lock(lockA); lock(&rq->lock); *** DEADLOCK *** Signed-off-by: Steven Rostedt Acked-by: Peter Zijlstra Cc: Frederic Weisbecker Cc: Linus Torvalds Cc: Andrew Morton Link: http://lkml.kernel.org/r/20110421014259.910720381@goodmis.org Signed-off-by: Ingo Molnar --- kernel/lockdep.c | 34 +++++++++++++++++++++++++++++----- 1 file changed, 29 insertions(+), 5 deletions(-) (limited to 'kernel') diff --git a/kernel/lockdep.c b/kernel/lockdep.c index c4cc5d1..0b497dd 100644 --- a/kernel/lockdep.c +++ b/kernel/lockdep.c @@ -1395,15 +1395,15 @@ print_shortest_lock_dependencies(struct lock_list *leaf, static void print_irq_lock_scenario(struct lock_list *safe_entry, struct lock_list *unsafe_entry, - struct held_lock *prev, - struct held_lock *next) + struct lock_class *prev_class, + struct lock_class *next_class) { struct lock_class *safe_class = safe_entry->class; struct lock_class *unsafe_class = unsafe_entry->class; - struct lock_class *middle_class = hlock_class(prev); + struct lock_class *middle_class = prev_class; if (middle_class == safe_class) - middle_class = hlock_class(next); + middle_class = next_class; /* * A direct locking problem where unsafe_class lock is taken @@ -1499,7 +1499,8 @@ print_bad_irq_dependency(struct task_struct *curr, print_stack_trace(forwards_entry->class->usage_traces + bit2, 1); printk("\nother info that might help us debug this:\n\n"); - print_irq_lock_scenario(backwards_entry, forwards_entry, prev, next); + print_irq_lock_scenario(backwards_entry, forwards_entry, + hlock_class(prev), hlock_class(next)); lockdep_print_held_locks(curr); @@ -2219,6 +2220,10 @@ print_irq_inversion_bug(struct task_struct *curr, struct held_lock *this, int forwards, const char *irqclass) { + struct lock_list *entry = other; + struct lock_list *middle = NULL; + int depth; + if (!debug_locks_off_graph_unlock() || debug_locks_silent) return 0; @@ -2237,6 +2242,25 @@ print_irq_inversion_bug(struct task_struct *curr, printk("\n\nand interrupts could create inverse lock ordering between them.\n\n"); printk("\nother info that might help us debug this:\n"); + + /* Find a middle lock (if one exists) */ + depth = get_lock_depth(other); + do { + if (depth == 0 && (entry != root)) { + printk("lockdep:%s bad path found in chain graph\n", __func__); + break; + } + middle = entry; + entry = get_lock_parent(entry); + depth--; + } while (entry && entry != root && (depth >= 0)); + if (forwards) + print_irq_lock_scenario(root, other, + middle ? middle->class : root->class, other->class); + else + print_irq_lock_scenario(other, root, + middle ? middle->class : other->class, root->class); + lockdep_print_held_locks(curr); printk("\nthe shortest dependencies between 2nd lock and 1st lock:\n"); -- cgit v1.1 From 6be8c3935b914dfbc24b27c91c2b6d583645e61a Mon Sep 17 00:00:00 2001 From: Steven Rostedt Date: Wed, 20 Apr 2011 21:41:58 -0400 Subject: lockdep: Replace "Bad BFS generated tree" message with something less cryptic The message of "Bad BFS generated tree" is a bit confusing. Replace it with a more sane error message. Thanks to Peter Zijlstra for helping me come up with a better message. Signed-off-by: Steven Rostedt Acked-by: Peter Zijlstra Cc: Frederic Weisbecker Cc: Linus Torvalds Cc: Andrew Morton Link: http://lkml.kernel.org/r/20110421014300.135521252@goodmis.org Signed-off-by: Ingo Molnar --- kernel/lockdep.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'kernel') diff --git a/kernel/lockdep.c b/kernel/lockdep.c index 0b497dd..270cfa4 100644 --- a/kernel/lockdep.c +++ b/kernel/lockdep.c @@ -1381,7 +1381,7 @@ print_shortest_lock_dependencies(struct lock_list *leaf, printk("\n"); if (depth == 0 && (entry != root)) { - printk("lockdep:%s bad BFS generated tree\n", __func__); + printk("lockdep:%s bad path found in chain graph\n", __func__); break; } -- cgit v1.1 From 282b5c2f6f663c008444321fd8fcdd374596046b Mon Sep 17 00:00:00 2001 From: Steven Rostedt Date: Wed, 20 Apr 2011 21:41:59 -0400 Subject: lockdep: Print a nicer description for simple irq lock inversions Lockdep output can be pretty cryptic, having nicer output can save a lot of head scratching. When a simple irq inversion scenario is detected by lockdep (lock A taken in interrupt context but also in thread context without disabling interrupts) we now get the following (hopefully more informative) output: other info that might help us debug this: Possible unsafe locking scenario: CPU0 ---- lock(lockA); lock(lockA); *** DEADLOCK *** Signed-off-by: Steven Rostedt Acked-by: Peter Zijlstra Cc: Frederic Weisbecker Cc: Linus Torvalds Cc: Andrew Morton Link: http://lkml.kernel.org/r/20110421014300.436140880@goodmis.org Signed-off-by: Ingo Molnar --- kernel/lockdep.c | 20 ++++++++++++++++++++ 1 file changed, 20 insertions(+) (limited to 'kernel') diff --git a/kernel/lockdep.c b/kernel/lockdep.c index 270cfa4..27c609f 100644 --- a/kernel/lockdep.c +++ b/kernel/lockdep.c @@ -2158,6 +2158,24 @@ static void check_chain_key(struct task_struct *curr) #endif } +static void +print_usage_bug_scenario(struct held_lock *lock) +{ + struct lock_class *class = hlock_class(lock); + + printk(" Possible unsafe locking scenario:\n\n"); + printk(" CPU0\n"); + printk(" ----\n"); + printk(" lock("); + __print_lock_name(class); + printk(");\n"); + printk(" \n"); + printk(" lock("); + __print_lock_name(class); + printk(");\n"); + printk("\n *** DEADLOCK ***\n\n"); +} + static int print_usage_bug(struct task_struct *curr, struct held_lock *this, enum lock_usage_bit prev_bit, enum lock_usage_bit new_bit) @@ -2186,6 +2204,8 @@ print_usage_bug(struct task_struct *curr, struct held_lock *this, print_irqtrace_events(curr); printk("\nother info that might help us debug this:\n"); + print_usage_bug_scenario(this); + lockdep_print_held_locks(curr); printk("\nstack backtrace:\n"); -- cgit v1.1 From e0944ee63f7249802be74454cef81c97630ae1cd Mon Sep 17 00:00:00 2001 From: Steven Rostedt Date: Wed, 20 Apr 2011 21:42:00 -0400 Subject: lockdep: Remove cmpxchg to update nr_chain_hlocks For some reason nr_chain_hlocks is updated with cmpxchg, but this is performed inside of the lockdep global "grab_lock()", which also makes simple modification of this variable atomic. Remove the cmpxchg logic for updating nr_chain_hlocks and simplify the code. Signed-off-by: Steven Rostedt Acked-by: Peter Zijlstra Cc: Frederic Weisbecker Cc: Linus Torvalds Cc: Andrew Morton Link: http://lkml.kernel.org/r/20110421014300.727863282@goodmis.org Signed-off-by: Ingo Molnar --- kernel/lockdep.c | 14 ++++---------- 1 file changed, 4 insertions(+), 10 deletions(-) (limited to 'kernel') diff --git a/kernel/lockdep.c b/kernel/lockdep.c index 27c609f..63437d0 100644 --- a/kernel/lockdep.c +++ b/kernel/lockdep.c @@ -1973,7 +1973,7 @@ static inline int lookup_chain_cache(struct task_struct *curr, struct list_head *hash_head = chainhashentry(chain_key); struct lock_chain *chain; struct held_lock *hlock_curr, *hlock_next; - int i, j, n, cn; + int i, j; if (DEBUG_LOCKS_WARN_ON(!irqs_disabled())) return 0; @@ -2033,15 +2033,9 @@ cache_hit: } i++; chain->depth = curr->lockdep_depth + 1 - i; - cn = nr_chain_hlocks; - while (cn + chain->depth <= MAX_LOCKDEP_CHAIN_HLOCKS) { - n = cmpxchg(&nr_chain_hlocks, cn, cn + chain->depth); - if (n == cn) - break; - cn = n; - } - if (likely(cn + chain->depth <= MAX_LOCKDEP_CHAIN_HLOCKS)) { - chain->base = cn; + if (likely(nr_chain_hlocks + chain->depth <= MAX_LOCKDEP_CHAIN_HLOCKS)) { + chain->base = nr_chain_hlocks; + nr_chain_hlocks += chain->depth; for (j = 0; j < chain->depth - 1; j++, i++) { int lock_id = curr->held_locks[i].class_idx - 1; chain_hlocks[chain->base + j] = lock_id; -- cgit v1.1 From 7f1b1244e159a8490d7fb13667c6cb7e1e75046b Mon Sep 17 00:00:00 2001 From: Paul Mundt Date: Thu, 7 Apr 2011 06:01:44 +0900 Subject: genirq: Support per-IRQ thread disabling. This adds support for disabling threading on a per-IRQ basis via the IRQ status instead of the IRQ flow, which is necessary for interrupts that don't follow the natural IRQ flow channels, such as those that are virtually created. The new APIs added are simply: irq_set_thread() irq_set_nothread() which follow the rest of the IRQ status routines. Chained handlers also have IRQ_NOTHREAD set on them automatically, making the lack of threading explicit rather than implicit. Subsequently, the nothread flag can be viewed through the standard genirq debugging facilities. [ tglx: Fixed cleanup fallout ] Signed-off-by: Paul Mundt Link: http://lkml.kernel.org/r/%3C20110406210135.GF18426%40linux-sh.org%3E Signed-off-by: Thomas Gleixner --- kernel/irq/chip.c | 1 + kernel/irq/debug.h | 1 + kernel/irq/manage.c | 3 ++- kernel/irq/settings.h | 17 +++++++++++++++++ 4 files changed, 21 insertions(+), 1 deletion(-) (limited to 'kernel') diff --git a/kernel/irq/chip.c b/kernel/irq/chip.c index 4af1e2b..52d856d 100644 --- a/kernel/irq/chip.c +++ b/kernel/irq/chip.c @@ -573,6 +573,7 @@ __irq_set_handler(unsigned int irq, irq_flow_handler_t handle, int is_chained, if (handle != handle_bad_irq && is_chained) { irq_settings_set_noprobe(desc); irq_settings_set_norequest(desc); + irq_settings_set_nothread(desc); irq_startup(desc); } out: diff --git a/kernel/irq/debug.h b/kernel/irq/debug.h index 306cba3..97a8bfa 100644 --- a/kernel/irq/debug.h +++ b/kernel/irq/debug.h @@ -27,6 +27,7 @@ static inline void print_irq_desc(unsigned int irq, struct irq_desc *desc) P(IRQ_PER_CPU); P(IRQ_NOPROBE); P(IRQ_NOREQUEST); + P(IRQ_NOTHREAD); P(IRQ_NOAUTOEN); PS(IRQS_AUTODETECT); diff --git a/kernel/irq/manage.c b/kernel/irq/manage.c index 07c1611..f7ce002 100644 --- a/kernel/irq/manage.c +++ b/kernel/irq/manage.c @@ -900,7 +900,8 @@ __setup_irq(unsigned int irq, struct irq_desc *desc, struct irqaction *new) */ new->handler = irq_nested_primary_handler; } else { - irq_setup_forced_threading(new); + if (irq_settings_can_thread(desc)) + irq_setup_forced_threading(new); } /* diff --git a/kernel/irq/settings.h b/kernel/irq/settings.h index 0d91730..f166783 100644 --- a/kernel/irq/settings.h +++ b/kernel/irq/settings.h @@ -8,6 +8,7 @@ enum { _IRQ_LEVEL = IRQ_LEVEL, _IRQ_NOPROBE = IRQ_NOPROBE, _IRQ_NOREQUEST = IRQ_NOREQUEST, + _IRQ_NOTHREAD = IRQ_NOTHREAD, _IRQ_NOAUTOEN = IRQ_NOAUTOEN, _IRQ_MOVE_PCNTXT = IRQ_MOVE_PCNTXT, _IRQ_NO_BALANCING = IRQ_NO_BALANCING, @@ -20,6 +21,7 @@ enum { #define IRQ_LEVEL GOT_YOU_MORON #define IRQ_NOPROBE GOT_YOU_MORON #define IRQ_NOREQUEST GOT_YOU_MORON +#define IRQ_NOTHREAD GOT_YOU_MORON #define IRQ_NOAUTOEN GOT_YOU_MORON #define IRQ_NESTED_THREAD GOT_YOU_MORON #undef IRQF_MODIFY_MASK @@ -94,6 +96,21 @@ static inline void irq_settings_set_norequest(struct irq_desc *desc) desc->status_use_accessors |= _IRQ_NOREQUEST; } +static inline bool irq_settings_can_thread(struct irq_desc *desc) +{ + return !(desc->status_use_accessors & _IRQ_NOTHREAD); +} + +static inline void irq_settings_clr_nothread(struct irq_desc *desc) +{ + desc->status_use_accessors &= ~_IRQ_NOTHREAD; +} + +static inline void irq_settings_set_nothread(struct irq_desc *desc) +{ + desc->status_use_accessors |= _IRQ_NOTHREAD; +} + static inline bool irq_settings_can_probe(struct irq_desc *desc) { return !(desc->status_use_accessors & _IRQ_NOPROBE); -- cgit v1.1 From 7d8280624797bbe2f5170bd3c85c75a8c9c74242 Mon Sep 17 00:00:00 2001 From: Thomas Gleixner Date: Sun, 3 Apr 2011 11:42:53 +0200 Subject: genirq: Implement a generic interrupt chip Implement a generic interrupt chip, which is configurable and is able to handle the most common irq chip implementations. Signed-off-by: Thomas Gleixner Cc: linux-arm-kernel@lists.infradead.org Tested-by: H Hartley Sweeten Tested-by: Tony Lindgren Tested-by; Kevin Hilman --- kernel/irq/Makefile | 1 + kernel/irq/generic-chip.c | 261 ++++++++++++++++++++++++++++++++++++++++++++++ 2 files changed, 262 insertions(+) create mode 100644 kernel/irq/generic-chip.c (limited to 'kernel') diff --git a/kernel/irq/Makefile b/kernel/irq/Makefile index 54329cd..e7a13bd 100644 --- a/kernel/irq/Makefile +++ b/kernel/irq/Makefile @@ -1,5 +1,6 @@ obj-y := irqdesc.o handle.o manage.o spurious.o resend.o chip.o dummychip.o devres.o +obj-y += generic-chip.o obj-$(CONFIG_GENERIC_IRQ_PROBE) += autoprobe.o obj-$(CONFIG_PROC_FS) += proc.o obj-$(CONFIG_GENERIC_PENDING_IRQ) += migration.o diff --git a/kernel/irq/generic-chip.c b/kernel/irq/generic-chip.c new file mode 100644 index 0000000..eb23e59 --- /dev/null +++ b/kernel/irq/generic-chip.c @@ -0,0 +1,261 @@ +/* + * Library implementing the most common irq chip callback functions + * + * Copyright (C) 2011, Thomas Gleixner + */ +#include +#include +#include +#include +#include + +#include "internals.h" + +static inline struct irq_chip_regs *cur_regs(struct irq_data *d) +{ + return &container_of(d->chip, struct irq_chip_type, chip)->regs; +} + +/** + * irq_gc_noop - NOOP function + * @d: irq_data + */ +void irq_gc_noop(struct irq_data *d) +{ +} + +/** + * irq_gc_mask_disable_reg - Mask chip via disable register + * @d: irq_data + * + * Chip has separate enable/disable registers instead of a single mask + * register. + */ +void irq_gc_mask_disable_reg(struct irq_data *d) +{ + struct irq_chip_generic *gc = irq_data_get_irq_chip_data(d); + u32 mask = 1 << (d->irq - gc->irq_base); + + irq_gc_lock(gc); + irq_reg_writel(mask, gc->reg_base + cur_regs(d)->disable); + gc->mask_cache &= ~mask; + irq_gc_unlock(gc); +} + +/** + * irq_gc_mask_set_mask_bit - Mask chip via setting bit in mask register + * @d: irq_data + * + * Chip has a single mask register. Values of this register are cached + * and protected by gc->lock + */ +void irq_gc_mask_set_bit(struct irq_data *d) +{ + struct irq_chip_generic *gc = irq_data_get_irq_chip_data(d); + u32 mask = 1 << (d->irq - gc->irq_base); + + irq_gc_lock(gc); + gc->mask_cache |= mask; + irq_reg_writel(gc->mask_cache, gc->reg_base + cur_regs(d)->mask); + irq_gc_unlock(gc); +} + +/** + * irq_gc_mask_set_mask_bit - Mask chip via clearing bit in mask register + * @d: irq_data + * + * Chip has a single mask register. Values of this register are cached + * and protected by gc->lock + */ +void irq_gc_mask_clr_bit(struct irq_data *d) +{ + struct irq_chip_generic *gc = irq_data_get_irq_chip_data(d); + u32 mask = 1 << (d->irq - gc->irq_base); + + irq_gc_lock(gc); + gc->mask_cache &= ~mask; + irq_reg_writel(gc->mask_cache, gc->reg_base + cur_regs(d)->mask); + irq_gc_unlock(gc); +} + +/** + * irq_gc_unmask_enable_reg - Unmask chip via enable register + * @d: irq_data + * + * Chip has separate enable/disable registers instead of a single mask + * register. + */ +void irq_gc_unmask_enable_reg(struct irq_data *d) +{ + struct irq_chip_generic *gc = irq_data_get_irq_chip_data(d); + u32 mask = 1 << (d->irq - gc->irq_base); + + irq_gc_lock(gc); + irq_reg_writel(mask, gc->reg_base + cur_regs(d)->enable); + gc->mask_cache |= mask; + irq_gc_unlock(gc); +} + +/** + * irq_gc_ack - Ack pending interrupt + * @d: irq_data + */ +void irq_gc_ack(struct irq_data *d) +{ + struct irq_chip_generic *gc = irq_data_get_irq_chip_data(d); + u32 mask = 1 << (d->irq - gc->irq_base); + + irq_gc_lock(gc); + irq_reg_writel(mask, gc->reg_base + cur_regs(d)->ack); + irq_gc_unlock(gc); +} + +/** + * irq_gc_mask_disable_reg_and_ack- Mask and ack pending interrupt + * @d: irq_data + */ +void irq_gc_mask_disable_reg_and_ack(struct irq_data *d) +{ + struct irq_chip_generic *gc = irq_data_get_irq_chip_data(d); + u32 mask = 1 << (d->irq - gc->irq_base); + + irq_gc_lock(gc); + irq_reg_writel(mask, gc->reg_base + cur_regs(d)->mask); + irq_reg_writel(mask, gc->reg_base + cur_regs(d)->ack); + irq_gc_unlock(gc); +} + +/** + * irq_gc_eoi - EOI interrupt + * @d: irq_data + */ +void irq_gc_eoi(struct irq_data *d) +{ + struct irq_chip_generic *gc = irq_data_get_irq_chip_data(d); + u32 mask = 1 << (d->irq - gc->irq_base); + + irq_gc_lock(gc); + irq_reg_writel(mask, gc->reg_base + cur_regs(d)->eoi); + irq_gc_unlock(gc); +} + +/** + * irq_gc_set_wake - Set/clr wake bit for an interrupt + * @d: irq_data + * + * For chips where the wake from suspend functionality is not + * configured in a separate register and the wakeup active state is + * just stored in a bitmask. + */ +int irq_gc_set_wake(struct irq_data *d, unsigned int on) +{ + struct irq_chip_generic *gc = irq_data_get_irq_chip_data(d); + u32 mask = 1 << (d->irq - gc->irq_base); + + if (!(mask & gc->wake_enabled)) + return -EINVAL; + + irq_gc_lock(gc); + if (on) + gc->wake_active |= mask; + else + gc->wake_active &= ~mask; + irq_gc_unlock(gc); + return 0; +} + +/** + * irq_alloc_generic_chip - Allocate a generic chip and initialize it + * @name: Name of the irq chip + * @num_ct: Number of irq_chip_type instances associated with this + * @irq_base: Interrupt base nr for this chip + * @reg_base: Register base address (virtual) + * @handler: Default flow handler associated with this chip + * + * Returns an initialized irq_chip_generic structure. The chip defaults + * to the primary (index 0) irq_chip_type and @handler + */ +struct irq_chip_generic * +irq_alloc_generic_chip(const char *name, int num_ct, unsigned int irq_base, + void __iomem *reg_base, irq_flow_handler_t handler) +{ + struct irq_chip_generic *gc; + unsigned long sz = sizeof(*gc) + num_ct * sizeof(struct irq_chip_type); + + gc = kzalloc(sz, GFP_KERNEL); + if (gc) { + raw_spin_lock_init(&gc->lock); + gc->num_ct = num_ct; + gc->irq_base = irq_base; + gc->reg_base = reg_base; + gc->chip_types->chip.name = name; + gc->chip_types->handler = handler; + } + return gc; +} + +/* + * Separate lockdep class for interrupt chip which can nest irq_desc + * lock. + */ +static struct lock_class_key irq_nested_lock_class; + +/** + * irq_setup_generic_chip - Setup a range of interrupts with a generic chip + * @gc: Generic irq chip holding all data + * @msk: Bitmask holding the irqs to initialize relative to gc->irq_base + * @flags: Flags for initialization + * @clr: IRQ_* bits to clear + * @set: IRQ_* bits to set + * + * Set up max. 32 interrupts starting from gc->irq_base. Note, this + * initializes all interrupts to the primary irq_chip_type and its + * associated handler. + */ +void irq_setup_generic_chip(struct irq_chip_generic *gc, u32 msk, + enum irq_gc_flags flags, unsigned int clr, + unsigned int set) +{ + struct irq_chip_type *ct = gc->chip_types; + unsigned int i; + + /* Init mask cache ? */ + if (flags & IRQ_GC_INIT_MASK_CACHE) + gc->mask_cache = irq_reg_readl(gc->reg_base + ct->regs.mask); + + for (i = gc->irq_base; msk; msk >>= 1, i++) { + if (!msk & 0x01) + continue; + + if (flags & IRQ_GC_INIT_NESTED_LOCK) + irq_set_lockdep_class(i, &irq_nested_lock_class); + + irq_set_chip_and_handler(i, &ct->chip, ct->handler); + irq_set_chip_data(i, gc); + irq_modify_status(i, clr, set); + } + gc->irq_cnt = i - gc->irq_base; +} + +/** + * irq_setup_alt_chip - Switch to alternative chip + * @d: irq_data for this interrupt + * @type Flow type to be initialized + * + * Only to be called from chip->irq_set_type() callbacks. + */ +int irq_setup_alt_chip(struct irq_data *d, unsigned int type) +{ + struct irq_chip_generic *gc = irq_data_get_irq_chip_data(d); + struct irq_chip_type *ct = gc->chip_types; + unsigned int i; + + for (i = 0; i < gc->num_ct; i++, ct++) { + if (ct->type & type) { + d->chip = &ct->chip; + irq_data_to_desc(d)->handle_irq = ct->handler; + return 0; + } + } + return -EINVAL; +} -- cgit v1.1 From cfefd21e693dca791bf9ecfc9dd3794facad533c Mon Sep 17 00:00:00 2001 From: Thomas Gleixner Date: Fri, 15 Apr 2011 22:36:08 +0200 Subject: genirq: Add chip suspend and resume callbacks These callbacks are only called in the syscore suspend/resume code on interrupt chips which have been registered via the generic irq chip mechanism. Calling those callbacks per irq would be rather icky, but with the generic irq chip mechanism we can call this per registered chip. Signed-off-by: Thomas Gleixner Cc: linux-arm-kernel@lists.infradead.org --- kernel/irq/generic-chip.c | 93 +++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 93 insertions(+) (limited to 'kernel') diff --git a/kernel/irq/generic-chip.c b/kernel/irq/generic-chip.c index eb23e59..31a9db7 100644 --- a/kernel/irq/generic-chip.c +++ b/kernel/irq/generic-chip.c @@ -8,9 +8,13 @@ #include #include #include +#include #include "internals.h" +static LIST_HEAD(gc_list); +static DEFINE_RAW_SPINLOCK(gc_lock); + static inline struct irq_chip_regs *cur_regs(struct irq_data *d) { return &container_of(d->chip, struct irq_chip_type, chip)->regs; @@ -219,6 +223,10 @@ void irq_setup_generic_chip(struct irq_chip_generic *gc, u32 msk, struct irq_chip_type *ct = gc->chip_types; unsigned int i; + raw_spin_lock(&gc_lock); + list_add_tail(&gc->list, &gc_list); + raw_spin_unlock(&gc_lock); + /* Init mask cache ? */ if (flags & IRQ_GC_INIT_MASK_CACHE) gc->mask_cache = irq_reg_readl(gc->reg_base + ct->regs.mask); @@ -259,3 +267,88 @@ int irq_setup_alt_chip(struct irq_data *d, unsigned int type) } return -EINVAL; } + +/** + * irq_remove_generic_chip - Remove a chip + * @gc: Generic irq chip holding all data + * @msk: Bitmask holding the irqs to initialize relative to gc->irq_base + * @clr: IRQ_* bits to clear + * @set: IRQ_* bits to set + * + * Remove up to 32 interrupts starting from gc->irq_base. + */ +void irq_remove_generic_chip(struct irq_chip_generic *gc, u32 msk, + unsigned int clr, unsigned int set) +{ + unsigned int i = gc->irq_base; + + raw_spin_lock(&gc_lock); + list_del(&gc->list); + raw_spin_unlock(&gc_lock); + + for (; msk; msk >>= 1, i++) { + if (!msk & 0x01) + continue; + + /* Remove handler first. That will mask the irq line */ + irq_set_handler(i, NULL); + irq_set_chip(i, &no_irq_chip); + irq_set_chip_data(i, NULL); + irq_modify_status(i, clr, set); + } +} + +#ifdef CONFIG_PM +static int irq_gc_suspend(void) +{ + struct irq_chip_generic *gc; + + list_for_each_entry(gc, &gc_list, list) { + struct irq_chip_type *ct = gc->chip_types; + + if (ct->chip.irq_suspend) + ct->chip.irq_suspend(irq_get_irq_data(gc->irq_base)); + } + return 0; +} + +static void irq_gc_resume(void) +{ + struct irq_chip_generic *gc; + + list_for_each_entry(gc, &gc_list, list) { + struct irq_chip_type *ct = gc->chip_types; + + if (ct->chip.irq_resume) + ct->chip.irq_resume(irq_get_irq_data(gc->irq_base)); + } +} +#else +#define irq_gc_suspend NULL +#define irq_gc_resume NULL +#endif + +static void irq_gc_shutdown(void) +{ + struct irq_chip_generic *gc; + + list_for_each_entry(gc, &gc_list, list) { + struct irq_chip_type *ct = gc->chip_types; + + if (ct->chip.irq_pm_shutdown) + ct->chip.irq_pm_shutdown(irq_get_irq_data(gc->irq_base)); + } +} + +static struct syscore_ops irq_gc_syscore_ops = { + .suspend = irq_gc_suspend, + .resume = irq_gc_resume, + .shutdown = irq_gc_shutdown, +}; + +static int __init irq_gc_init_ops(void) +{ + register_syscore_ops(&irq_gc_syscore_ops); + return 0; +} +device_initcall(irq_gc_init_ops); -- cgit v1.1 From 625f2a378e5a10f45fdc37932fc9f8a21676de9e Mon Sep 17 00:00:00 2001 From: Jonathan Corbet Date: Fri, 22 Apr 2011 11:19:10 -0600 Subject: sched: Get rid of lock_depth Neil Brown pointed out that lock_depth somehow escaped the BKL removal work. Let's get rid of it now. Note that the perf scripting utilities still have a bunch of code for dealing with common_lock_depth in tracepoints; I have left that in place in case anybody wants to use that code with older kernels. Suggested-by: Neil Brown Signed-off-by: Jonathan Corbet Cc: Arnd Bergmann Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: Linus Torvalds Cc: Andrew Morton Link: http://lkml.kernel.org/r/20110422111910.456c0e84@bike.lwn.net Signed-off-by: Ingo Molnar --- kernel/fork.c | 1 - kernel/mutex.c | 7 ------- kernel/sched.c | 11 +---------- kernel/sched_debug.c | 4 ---- kernel/trace/trace_kprobe.c | 1 - 5 files changed, 1 insertion(+), 23 deletions(-) (limited to 'kernel') diff --git a/kernel/fork.c b/kernel/fork.c index e7548de..aca6287 100644 --- a/kernel/fork.c +++ b/kernel/fork.c @@ -1103,7 +1103,6 @@ static struct task_struct *copy_process(unsigned long clone_flags, posix_cpu_timers_init(p); - p->lock_depth = -1; /* -1 = no lock */ do_posix_clock_monotonic_gettime(&p->start_time); p->real_start_time = p->start_time; monotonic_to_bootbased(&p->real_start_time); diff --git a/kernel/mutex.c b/kernel/mutex.c index fe4706c..2c938e2 100644 --- a/kernel/mutex.c +++ b/kernel/mutex.c @@ -163,13 +163,6 @@ __mutex_lock_common(struct mutex *lock, long state, unsigned int subclass, struct task_struct *owner; /* - * If we own the BKL, then don't spin. The owner of - * the mutex might be waiting on us to release the BKL. - */ - if (unlikely(current->lock_depth >= 0)) - break; - - /* * If there's an owner, wait for it to either * release the lock or go to sleep. */ diff --git a/kernel/sched.c b/kernel/sched.c index 8cb0a57..9cde2dd 100644 --- a/kernel/sched.c +++ b/kernel/sched.c @@ -4121,12 +4121,6 @@ static inline void schedule_debug(struct task_struct *prev) profile_hit(SCHED_PROFILING, __builtin_return_address(0)); schedstat_inc(this_rq(), sched_count); -#ifdef CONFIG_SCHEDSTATS - if (unlikely(prev->lock_depth >= 0)) { - schedstat_inc(this_rq(), rq_sched_info.bkl_count); - schedstat_inc(prev, sched_info.bkl_count); - } -#endif } static void put_prev_task(struct rq *rq, struct task_struct *prev) @@ -5852,11 +5846,8 @@ void __cpuinit init_idle(struct task_struct *idle, int cpu) raw_spin_unlock_irqrestore(&rq->lock, flags); /* Set the preempt count _outside_ the spinlocks! */ -#if defined(CONFIG_PREEMPT) - task_thread_info(idle)->preempt_count = (idle->lock_depth >= 0); -#else task_thread_info(idle)->preempt_count = 0; -#endif + /* * The idle tasks have their own, simple scheduling class: */ diff --git a/kernel/sched_debug.c b/kernel/sched_debug.c index 3669bec6..a6710a1 100644 --- a/kernel/sched_debug.c +++ b/kernel/sched_debug.c @@ -296,9 +296,6 @@ static void print_cpu(struct seq_file *m, int cpu) P(ttwu_count); P(ttwu_local); - SEQ_printf(m, " .%-30s: %d\n", "bkl_count", - rq->rq_sched_info.bkl_count); - #undef P #undef P64 #endif @@ -441,7 +438,6 @@ void proc_sched_show_task(struct task_struct *p, struct seq_file *m) P(se.statistics.wait_count); PN(se.statistics.iowait_sum); P(se.statistics.iowait_count); - P(sched_info.bkl_count); P(se.nr_migrations); P(se.statistics.nr_migrations_cold); P(se.statistics.nr_failed_migrations_affine); diff --git a/kernel/trace/trace_kprobe.c b/kernel/trace/trace_kprobe.c index 35d55a3..f925c45 100644 --- a/kernel/trace/trace_kprobe.c +++ b/kernel/trace/trace_kprobe.c @@ -53,7 +53,6 @@ const char *reserved_field_names[] = { "common_preempt_count", "common_pid", "common_tgid", - "common_lock_depth", FIELD_STRING_IP, FIELD_STRING_RETIP, FIELD_STRING_FUNC, -- cgit v1.1 From bf26c018490c2fce7fe9b629083b96ce0e6ad019 Mon Sep 17 00:00:00 2001 From: Frederic Weisbecker Date: Thu, 7 Apr 2011 16:53:20 +0200 Subject: ptrace: Prepare to fix racy accesses on task breakpoints When a task is traced and is in a stopped state, the tracer may execute a ptrace request to examine the tracee state and get its task struct. Right after, the tracee can be killed and thus its breakpoints released. This can happen concurrently when the tracer is in the middle of reading or modifying these breakpoints, leading to dereferencing a freed pointer. Hence, to prepare the fix, create a generic breakpoint reference holding API. When a reference on the breakpoints of a task is held, the breakpoints won't be released until the last reference is dropped. After that, no more ptrace request on the task's breakpoints can be serviced for the tracer. Reported-by: Oleg Nesterov Signed-off-by: Frederic Weisbecker Cc: Ingo Molnar Cc: Peter Zijlstra Cc: Will Deacon Cc: Prasad Cc: Paul Mundt Cc: v2.6.33.. Link: http://lkml.kernel.org/r/1302284067-7860-2-git-send-email-fweisbec@gmail.com --- kernel/exit.c | 2 +- kernel/ptrace.c | 17 +++++++++++++++++ 2 files changed, 18 insertions(+), 1 deletion(-) (limited to 'kernel') diff --git a/kernel/exit.c b/kernel/exit.c index f5d2f63..8dd8741 100644 --- a/kernel/exit.c +++ b/kernel/exit.c @@ -1016,7 +1016,7 @@ NORET_TYPE void do_exit(long code) /* * FIXME: do that only when needed, using sched_exit tracepoint */ - flush_ptrace_hw_breakpoint(tsk); + ptrace_put_breakpoints(tsk); exit_notify(tsk, group_dead); #ifdef CONFIG_NUMA diff --git a/kernel/ptrace.c b/kernel/ptrace.c index 0fc1eed..dc7ab65 100644 --- a/kernel/ptrace.c +++ b/kernel/ptrace.c @@ -22,6 +22,7 @@ #include #include #include +#include /* @@ -879,3 +880,19 @@ asmlinkage long compat_sys_ptrace(compat_long_t request, compat_long_t pid, return ret; } #endif /* CONFIG_COMPAT */ + +#ifdef CONFIG_HAVE_HW_BREAKPOINT +int ptrace_get_breakpoints(struct task_struct *tsk) +{ + if (atomic_inc_not_zero(&tsk->ptrace_bp_refcnt)) + return 0; + + return -1; +} + +void ptrace_put_breakpoints(struct task_struct *tsk) +{ + if (atomic_dec_and_test(&tsk->ptrace_bp_refcnt)) + flush_ptrace_hw_breakpoint(tsk); +} +#endif /* CONFIG_HAVE_HW_BREAKPOINT */ -- cgit v1.1 From e7e09cd667a43d8287f85d453a16fc0ec1e2c7b7 Mon Sep 17 00:00:00 2001 From: Jonathan Cameron Date: Tue, 19 Apr 2011 12:43:47 +0100 Subject: params.c: Use new strtobool function to process boolean inputs No functional changes. Signed-off-by: Jonathan Cameron Signed-off-by: Greg Kroah-Hartman --- kernel/params.c | 14 ++++---------- 1 file changed, 4 insertions(+), 10 deletions(-) (limited to 'kernel') diff --git a/kernel/params.c b/kernel/params.c index 7ab388a..6888761 100644 --- a/kernel/params.c +++ b/kernel/params.c @@ -297,21 +297,15 @@ EXPORT_SYMBOL(param_ops_charp); int param_set_bool(const char *val, const struct kernel_param *kp) { bool v; + int ret; /* No equals means "set"... */ if (!val) val = "1"; /* One of =[yYnN01] */ - switch (val[0]) { - case 'y': case 'Y': case '1': - v = true; - break; - case 'n': case 'N': case '0': - v = false; - break; - default: - return -EINVAL; - } + ret = strtobool(val, &v); + if (ret) + return ret; if (kp->flags & KPARAM_ISBOOL) *(bool *)kp->arg = v; -- cgit v1.1 From 1437f5bca3c2d162f058cba37dfbeb20f619040d Mon Sep 17 00:00:00 2001 From: Hillf Danton Date: Sat, 23 Apr 2011 21:29:05 +0800 Subject: sched: Remove noop in alloc_rt_sched_group() The rq varible, though computed for each possible cpu, has nothing to do in the function, so it can be removed. This also eliminates a build warning. Signed-off-by: Hillf Danton Reviewed-by: Yong Zhang Signed-off-by: Peter Zijlstra Link: http://lkml.kernel.org/r/BANLkTin-FfQfqW5ym1iuEmrk8s777Y1LAg@mail.gmail.com Signed-off-by: Ingo Molnar --- kernel/sched.c | 3 --- 1 file changed, 3 deletions(-) (limited to 'kernel') diff --git a/kernel/sched.c b/kernel/sched.c index 9cde2dd..f11a2a5 100644 --- a/kernel/sched.c +++ b/kernel/sched.c @@ -8226,7 +8226,6 @@ int alloc_rt_sched_group(struct task_group *tg, struct task_group *parent) { struct rt_rq *rt_rq; struct sched_rt_entity *rt_se; - struct rq *rq; int i; tg->rt_rq = kzalloc(sizeof(rt_rq) * nr_cpu_ids, GFP_KERNEL); @@ -8240,8 +8239,6 @@ int alloc_rt_sched_group(struct task_group *tg, struct task_group *parent) ktime_to_ns(def_rt_bandwidth.rt_period), 0); for_each_possible_cpu(i) { - rq = cpu_rq(i); - rt_rq = kzalloc_node(sizeof(struct rt_rq), GFP_KERNEL, cpu_to_node(i)); if (!rt_rq) -- cgit v1.1 From e11feaa1192a079ba8e88a12121e9b12d55d4239 Mon Sep 17 00:00:00 2001 From: Jeff Mahoney Date: Wed, 27 Apr 2011 14:27:24 -0400 Subject: watchdog, hung_task_timeout: Add Kconfig configurable default This patch allows the default value for sysctl_hung_task_timeout_secs to be set at build time. The feature carries virtually no overhead, so it makes sense to keep it enabled. On heavily loaded systems, though, it can end up triggering stack traces when there is no bug other than the system being underprovisioned. We use this patch to keep the hung task facility available but disabled at boot-time. The default of 120 seconds is preserved. As a note, commit e162b39a may have accidentally reverted commit fb822db4, which raised the default from 120 seconds to 480 seconds. Signed-off-by: Jeff Mahoney Acked-by: Mandeep Singh Baines Link: http://lkml.kernel.org/r/4DB8600C.8080000@suse.com Signed-off-by: Ingo Molnar --- kernel/hung_task.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'kernel') diff --git a/kernel/hung_task.c b/kernel/hung_task.c index 53ead17..ea64012 100644 --- a/kernel/hung_task.c +++ b/kernel/hung_task.c @@ -33,7 +33,7 @@ unsigned long __read_mostly sysctl_hung_task_check_count = PID_MAX_LIMIT; /* * Zero means infinite timeout - no checking done: */ -unsigned long __read_mostly sysctl_hung_task_timeout_secs = 120; +unsigned long __read_mostly sysctl_hung_task_timeout_secs = CONFIG_DEFAULT_HUNG_TASK_TIMEOUT; unsigned long __read_mostly sysctl_hung_task_warnings = 10; -- cgit v1.1 From 85eb8c8d0b0900c073b0e6f89979ac9c439ade1a Mon Sep 17 00:00:00 2001 From: "Rafael J. Wysocki" Date: Sat, 30 Apr 2011 00:25:44 +0200 Subject: PM / Runtime: Generic clock manipulation rountines for runtime PM (v6) Many different platforms and subsystems may want to disable device clocks during suspend and enable them during resume which is going to be done in a very similar way in all those cases. For this reason, provide generic routines for the manipulation of device clocks during suspend and resume. Convert the ARM shmobile platform to using the new routines. Signed-off-by: Rafael J. Wysocki --- kernel/power/Kconfig | 4 ++++ 1 file changed, 4 insertions(+) (limited to 'kernel') diff --git a/kernel/power/Kconfig b/kernel/power/Kconfig index 6de9a8f..d74ad4a 100644 --- a/kernel/power/Kconfig +++ b/kernel/power/Kconfig @@ -229,3 +229,7 @@ config PM_OPP representing individual voltage domains and provides SOC implementations a ready to use framework to manage OPPs. For more information, read + +config PM_RUNTIME_CLK + def_bool y + depends on PM_RUNTIME && HAVE_CLK -- cgit v1.1 From 058e297d34a404caaa5ed277de15698d8dc43000 Mon Sep 17 00:00:00 2001 From: Steven Rostedt Date: Fri, 29 Apr 2011 22:35:33 -0400 Subject: ftrace: Only update the function code on write to filter files If function tracing is enabled, a read of the filter files will cause the call to stop_machine to update the function trace sites. It should only call stop_machine on write. Cc: stable@kernel.org Signed-off-by: Steven Rostedt --- kernel/trace/ftrace.c | 12 +++++++----- 1 file changed, 7 insertions(+), 5 deletions(-) (limited to 'kernel') diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c index ee24fa1..666880d 100644 --- a/kernel/trace/ftrace.c +++ b/kernel/trace/ftrace.c @@ -2413,14 +2413,16 @@ ftrace_regex_release(struct inode *inode, struct file *file, int enable) ftrace_match_records(parser->buffer, parser->idx, enable); } - mutex_lock(&ftrace_lock); - if (ftrace_start_up && ftrace_enabled) - ftrace_run_update_code(FTRACE_ENABLE_CALLS); - mutex_unlock(&ftrace_lock); - trace_parser_put(parser); kfree(iter); + if (file->f_mode & FMODE_WRITE) { + mutex_lock(&ftrace_lock); + if (ftrace_start_up && ftrace_enabled) + ftrace_run_update_code(FTRACE_ENABLE_CALLS); + mutex_unlock(&ftrace_lock); + } + mutex_unlock(&ftrace_regex_lock); return 0; } -- cgit v1.1 From 0778d9ad33898faab7bf6316108b471790376e35 Mon Sep 17 00:00:00 2001 From: Steven Rostedt Date: Fri, 29 Apr 2011 10:36:31 -0400 Subject: ftrace: Make FTRACE_WARN_ON() work in if condition Let FTRACE_WARN_ON() be used as a stand alone statement or inside a conditional: if (FTRACE_WARN_ON(x)) Signed-off-by: Steven Rostedt --- kernel/trace/ftrace.c | 16 ++++++++++------ 1 file changed, 10 insertions(+), 6 deletions(-) (limited to 'kernel') diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c index ee24fa1..4ff65599 100644 --- a/kernel/trace/ftrace.c +++ b/kernel/trace/ftrace.c @@ -39,16 +39,20 @@ #include "trace_stat.h" #define FTRACE_WARN_ON(cond) \ - do { \ - if (WARN_ON(cond)) \ + ({ \ + int ___r = cond; \ + if (WARN_ON(___r)) \ ftrace_kill(); \ - } while (0) + ___r; \ + }) #define FTRACE_WARN_ON_ONCE(cond) \ - do { \ - if (WARN_ON_ONCE(cond)) \ + ({ \ + int ___r = cond; \ + if (WARN_ON_ONCE(___r)) \ ftrace_kill(); \ - } while (0) + ___r; \ + }) /* hash bits for specific function selection */ #define FTRACE_HASH_BITS 7 -- cgit v1.1 From 8ab2b7efd3e2ccf2c2dda3206b8171ecdbd0af40 Mon Sep 17 00:00:00 2001 From: Steven Rostedt Date: Thu, 21 Apr 2011 22:41:35 -0400 Subject: ftrace: Remove unnecessary disabling of irqs The disabling of interrupts around ftrace_update_code() was used to protect against the evil ftrace daemon from years past. But that daemon has long been killed. It is safe to keep interrupts enabled while updating the initial mcount into nops. The ftrace_mutex is also held which keeps other users at bay. Signed-off-by: Steven Rostedt --- kernel/trace/ftrace.c | 4 ---- 1 file changed, 4 deletions(-) (limited to 'kernel') diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c index 4ff65599..f199fb2 100644 --- a/kernel/trace/ftrace.c +++ b/kernel/trace/ftrace.c @@ -2707,7 +2707,6 @@ static int ftrace_process_locs(struct module *mod, { unsigned long *p; unsigned long addr; - unsigned long flags; mutex_lock(&ftrace_lock); p = start; @@ -2724,10 +2723,7 @@ static int ftrace_process_locs(struct module *mod, ftrace_record_ip(addr); } - /* disable interrupts to prevent kstop machine */ - local_irq_save(flags); ftrace_update_code(mod); - local_irq_restore(flags); mutex_unlock(&ftrace_lock); return 0; -- cgit v1.1 From 3499e461147636bf55c41128d83b679ac6ab2d86 Mon Sep 17 00:00:00 2001 From: Steven Rostedt Date: Thu, 21 Apr 2011 22:59:12 -0400 Subject: ftrace: Remove failures file The failures file in the debugfs tracing directory would list the functions that failed to convert when the old dead ftrace daemon tried to update code but failed. Since this code is now dead along with the daemon the failures file is useless. Remove it. Signed-off-by: Steven Rostedt --- kernel/trace/ftrace.c | 39 ++------------------------------------- 1 file changed, 2 insertions(+), 37 deletions(-) (limited to 'kernel') diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c index f199fb2..97b30f8 100644 --- a/kernel/trace/ftrace.c +++ b/kernel/trace/ftrace.c @@ -1355,9 +1355,8 @@ static int __init ftrace_dyn_table_alloc(unsigned long num_to_init) enum { FTRACE_ITER_FILTER = (1 << 0), FTRACE_ITER_NOTRACE = (1 << 1), - FTRACE_ITER_FAILURES = (1 << 2), - FTRACE_ITER_PRINTALL = (1 << 3), - FTRACE_ITER_HASH = (1 << 4), + FTRACE_ITER_PRINTALL = (1 << 2), + FTRACE_ITER_HASH = (1 << 3), }; #define FTRACE_BUFF_MAX (KSYM_SYMBOL_LEN+4) /* room for wildcards */ @@ -1487,12 +1486,6 @@ t_next(struct seq_file *m, void *v, loff_t *pos) rec = &iter->pg->records[iter->idx++]; if ((rec->flags & FTRACE_FL_FREE) || - (!(iter->flags & FTRACE_ITER_FAILURES) && - (rec->flags & FTRACE_FL_FAILED)) || - - ((iter->flags & FTRACE_ITER_FAILURES) && - !(rec->flags & FTRACE_FL_FAILED)) || - ((iter->flags & FTRACE_ITER_FILTER) && !(rec->flags & FTRACE_FL_FILTER)) || @@ -1633,24 +1626,6 @@ ftrace_avail_open(struct inode *inode, struct file *file) return ret; } -static int -ftrace_failures_open(struct inode *inode, struct file *file) -{ - int ret; - struct seq_file *m; - struct ftrace_iterator *iter; - - ret = ftrace_avail_open(inode, file); - if (!ret) { - m = file->private_data; - iter = m->private; - iter->flags = FTRACE_ITER_FAILURES; - } - - return ret; -} - - static void ftrace_filter_reset(int enable) { struct ftrace_page *pg; @@ -2448,13 +2423,6 @@ static const struct file_operations ftrace_avail_fops = { .release = seq_release_private, }; -static const struct file_operations ftrace_failures_fops = { - .open = ftrace_failures_open, - .read = seq_read, - .llseek = seq_lseek, - .release = seq_release_private, -}; - static const struct file_operations ftrace_filter_fops = { .open = ftrace_filter_open, .read = seq_read, @@ -2683,9 +2651,6 @@ static __init int ftrace_init_dyn_debugfs(struct dentry *d_tracer) trace_create_file("available_filter_functions", 0444, d_tracer, NULL, &ftrace_avail_fops); - trace_create_file("failures", 0444, - d_tracer, NULL, &ftrace_failures_fops); - trace_create_file("set_ftrace_filter", 0644, d_tracer, NULL, &ftrace_filter_fops); -- cgit v1.1 From 45a4a2372b364107cabea79f255b333236626416 Mon Sep 17 00:00:00 2001 From: Steven Rostedt Date: Thu, 21 Apr 2011 23:16:46 -0400 Subject: ftrace: Remove FTRACE_FL_FAILED flag Since we disable all function tracer processing if we detect that a modification of a instruction had failed, we do not need to track that the record has failed. No more ftrace processing is allowed, and the FTRACE_FL_FAILED flag is pointless. Removing this flag simplifies some of the code, but some ftrace_disabled checks needed to be added or move around a little. Signed-off-by: Steven Rostedt --- kernel/trace/ftrace.c | 76 +++++++++++++++++++++++++++++++-------------------- 1 file changed, 47 insertions(+), 29 deletions(-) (limited to 'kernel') diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c index 97b30f8..eb19fae 100644 --- a/kernel/trace/ftrace.c +++ b/kernel/trace/ftrace.c @@ -1083,19 +1083,20 @@ static void ftrace_replace_code(int enable) struct ftrace_page *pg; int failed; + if (unlikely(ftrace_disabled)) + return; + do_for_each_ftrace_rec(pg, rec) { /* * Skip over free records, records that have * failed and not converted. */ if (rec->flags & FTRACE_FL_FREE || - rec->flags & FTRACE_FL_FAILED || !(rec->flags & FTRACE_FL_CONVERTED)) continue; failed = __ftrace_replace_code(rec, enable); if (failed) { - rec->flags |= FTRACE_FL_FAILED; ftrace_bug(failed, rec->ip); /* Stop processing */ return; @@ -1111,10 +1112,12 @@ ftrace_code_disable(struct module *mod, struct dyn_ftrace *rec) ip = rec->ip; + if (unlikely(ftrace_disabled)) + return 0; + ret = ftrace_make_nop(mod, rec, MCOUNT_ADDR); if (ret) { ftrace_bug(ret, ip); - rec->flags |= FTRACE_FL_FAILED; return 0; } return 1; @@ -1466,6 +1469,9 @@ t_next(struct seq_file *m, void *v, loff_t *pos) struct ftrace_iterator *iter = m->private; struct dyn_ftrace *rec = NULL; + if (unlikely(ftrace_disabled)) + return NULL; + if (iter->flags & FTRACE_ITER_HASH) return t_hash_next(m, pos); @@ -1518,6 +1524,10 @@ static void *t_start(struct seq_file *m, loff_t *pos) loff_t l; mutex_lock(&ftrace_lock); + + if (unlikely(ftrace_disabled)) + return NULL; + /* * If an lseek was done, then reset and start from beginning. */ @@ -1636,8 +1646,6 @@ static void ftrace_filter_reset(int enable) if (enable) ftrace_filtered = 0; do_for_each_ftrace_rec(pg, rec) { - if (rec->flags & FTRACE_FL_FAILED) - continue; rec->flags &= ~type; } while_for_each_ftrace_rec(); mutex_unlock(&ftrace_lock); @@ -1767,9 +1775,6 @@ static int ftrace_match_records(char *buff, int len, int enable) mutex_lock(&ftrace_lock); do_for_each_ftrace_rec(pg, rec) { - if (rec->flags & FTRACE_FL_FAILED) - continue; - if (ftrace_match_record(rec, search, search_len, type)) { if (not) rec->flags &= ~flag; @@ -1837,10 +1842,11 @@ static int ftrace_match_module_records(char *buff, char *mod, int enable) } mutex_lock(&ftrace_lock); - do_for_each_ftrace_rec(pg, rec) { - if (rec->flags & FTRACE_FL_FAILED) - continue; + if (unlikely(ftrace_disabled)) + goto out_unlock; + + do_for_each_ftrace_rec(pg, rec) { if (ftrace_match_module_record(rec, mod, search, search_len, type)) { @@ -1854,6 +1860,7 @@ static int ftrace_match_module_records(char *buff, char *mod, int enable) ftrace_filtered = 1; } while_for_each_ftrace_rec(); + out_unlock: mutex_unlock(&ftrace_lock); return found; @@ -2008,10 +2015,11 @@ register_ftrace_function_probe(char *glob, struct ftrace_probe_ops *ops, return -EINVAL; mutex_lock(&ftrace_lock); - do_for_each_ftrace_rec(pg, rec) { - if (rec->flags & FTRACE_FL_FAILED) - continue; + if (unlikely(ftrace_disabled)) + goto out_unlock; + + do_for_each_ftrace_rec(pg, rec) { if (!ftrace_match_record(rec, search, len, type)) continue; @@ -2218,6 +2226,10 @@ ftrace_regex_write(struct file *file, const char __user *ubuf, mutex_lock(&ftrace_regex_lock); + ret = -ENODEV; + if (unlikely(ftrace_disabled)) + goto out_unlock; + if (file->f_mode & FMODE_READ) { struct seq_file *m = file->private_data; iter = m->private; @@ -2545,9 +2557,6 @@ ftrace_set_func(unsigned long *array, int *idx, char *buffer) bool exists; int i; - if (ftrace_disabled) - return -ENODEV; - /* decode regex */ type = filter_parse_regex(buffer, strlen(buffer), &search, ¬); if (!not && *idx >= FTRACE_GRAPH_MAX_FUNCS) @@ -2556,9 +2565,15 @@ ftrace_set_func(unsigned long *array, int *idx, char *buffer) search_len = strlen(search); mutex_lock(&ftrace_lock); + + if (unlikely(ftrace_disabled)) { + mutex_unlock(&ftrace_lock); + return -ENODEV; + } + do_for_each_ftrace_rec(pg, rec) { - if (rec->flags & (FTRACE_FL_FAILED | FTRACE_FL_FREE)) + if (rec->flags & FTRACE_FL_FREE) continue; if (ftrace_match_record(rec, search, search_len, type)) { @@ -2700,10 +2715,11 @@ void ftrace_release_mod(struct module *mod) struct dyn_ftrace *rec; struct ftrace_page *pg; + mutex_lock(&ftrace_lock); + if (ftrace_disabled) - return; + goto out_unlock; - mutex_lock(&ftrace_lock); do_for_each_ftrace_rec(pg, rec) { if (within_module_core(rec->ip, mod)) { /* @@ -2714,6 +2730,7 @@ void ftrace_release_mod(struct module *mod) ftrace_free_rec(rec); } } while_for_each_ftrace_rec(); + out_unlock: mutex_unlock(&ftrace_lock); } @@ -3108,16 +3125,17 @@ void ftrace_kill(void) */ int register_ftrace_function(struct ftrace_ops *ops) { - int ret; - - if (unlikely(ftrace_disabled)) - return -1; + int ret = -1; mutex_lock(&ftrace_lock); + if (unlikely(ftrace_disabled)) + goto out_unlock; + ret = __register_ftrace_function(ops); ftrace_startup(0); + out_unlock: mutex_unlock(&ftrace_lock); return ret; } @@ -3145,14 +3163,14 @@ ftrace_enable_sysctl(struct ctl_table *table, int write, void __user *buffer, size_t *lenp, loff_t *ppos) { - int ret; - - if (unlikely(ftrace_disabled)) - return -ENODEV; + int ret = -ENODEV; mutex_lock(&ftrace_lock); - ret = proc_dointvec(table, write, buffer, lenp, ppos); + if (unlikely(ftrace_disabled)) + goto out; + + ret = proc_dointvec(table, write, buffer, lenp, ppos); if (ret || !write || (last_ftrace_enabled == !!ftrace_enabled)) goto out; -- cgit v1.1 From d2c8c3eafbf715306ec891e7ca52d3d999acbe31 Mon Sep 17 00:00:00 2001 From: Steven Rostedt Date: Mon, 25 Apr 2011 14:32:42 -0400 Subject: ftrace: Remove FTRACE_FL_CONVERTED flag Since we disable all function tracer processing if we detect that a modification of a instruction had failed, we do not need to track that the record has failed. No more ftrace processing is allowed, and the FTRACE_FL_CONVERTED flag is pointless. The FTRACE_FL_CONVERTED flag was used to denote records that were successfully converted from mcount calls into nops. But if a single record fails, all of ftrace is disabled. Signed-off-by: Steven Rostedt --- kernel/trace/ftrace.c | 12 ++++-------- 1 file changed, 4 insertions(+), 8 deletions(-) (limited to 'kernel') diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c index eb19fae..9abaaf4 100644 --- a/kernel/trace/ftrace.c +++ b/kernel/trace/ftrace.c @@ -1087,12 +1087,8 @@ static void ftrace_replace_code(int enable) return; do_for_each_ftrace_rec(pg, rec) { - /* - * Skip over free records, records that have - * failed and not converted. - */ - if (rec->flags & FTRACE_FL_FREE || - !(rec->flags & FTRACE_FL_CONVERTED)) + /* Skip over free records */ + if (rec->flags & FTRACE_FL_FREE) continue; failed = __ftrace_replace_code(rec, enable); @@ -1280,10 +1276,10 @@ static int ftrace_update_code(struct module *mod) */ if (!ftrace_code_disable(mod, p)) { ftrace_free_rec(p); - continue; + /* Game over */ + break; } - p->flags |= FTRACE_FL_CONVERTED; ftrace_update_cnt++; /* -- cgit v1.1 From 996e87be7f537fb34638875dd37083166c733425 Mon Sep 17 00:00:00 2001 From: Steven Rostedt Date: Tue, 26 Apr 2011 16:11:03 -0400 Subject: ftrace: Move record update for normal and modules into a separate function The updating of a function record is moved to a single function. This will allow us to add specific changes in one location for both modules and kernel functions. Later patches will determine if the function record itself needs to be updated (which enables the mcount caller), or just the ftrace_ops needs the update. Signed-off-by: Steven Rostedt --- kernel/trace/ftrace.c | 19 +++++++++++-------- 1 file changed, 11 insertions(+), 8 deletions(-) (limited to 'kernel') diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c index 9abaaf4..5b758ea 100644 --- a/kernel/trace/ftrace.c +++ b/kernel/trace/ftrace.c @@ -1743,6 +1743,15 @@ static int ftrace_match(char *str, char *regex, int len, int type) return matched; } +static void +update_record(struct dyn_ftrace *rec, unsigned long flag, int not) +{ + if (not) + rec->flags &= ~flag; + else + rec->flags |= flag; +} + static int ftrace_match_record(struct dyn_ftrace *rec, char *regex, int len, int type) { @@ -1772,10 +1781,7 @@ static int ftrace_match_records(char *buff, int len, int enable) do_for_each_ftrace_rec(pg, rec) { if (ftrace_match_record(rec, search, search_len, type)) { - if (not) - rec->flags &= ~flag; - else - rec->flags |= flag; + update_record(rec, flag, not); found = 1; } /* @@ -1846,10 +1852,7 @@ static int ftrace_match_module_records(char *buff, char *mod, int enable) if (ftrace_match_module_record(rec, mod, search, search_len, type)) { - if (not) - rec->flags &= ~flag; - else - rec->flags |= flag; + update_record(rec, flag, not); found = 1; } if (enable && (rec->flags & FTRACE_FL_FILTER)) -- cgit v1.1 From 491d0dcfb9707e1f83eff93ca503eb7573162ef2 Mon Sep 17 00:00:00 2001 From: Steven Rostedt Date: Wed, 27 Apr 2011 21:43:36 -0400 Subject: ftrace: Consolidate updating of ftrace_trace_function There are three locations that perform almost identical functions in order to update the ftrace_trace_function (the ftrace function variable that gets called by mcount). Consolidate these into a single function called update_ftrace_function(). Signed-off-by: Steven Rostedt --- kernel/trace/ftrace.c | 95 ++++++++++++++++++--------------------------------- 1 file changed, 34 insertions(+), 61 deletions(-) (limited to 'kernel') diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c index 5b758ea..33bcc71 100644 --- a/kernel/trace/ftrace.c +++ b/kernel/trace/ftrace.c @@ -151,6 +151,34 @@ static void ftrace_test_stop_func(unsigned long ip, unsigned long parent_ip) } #endif +static void update_ftrace_function(void) +{ + ftrace_func_t func; + + /* + * If there's only one function registered, then call that + * function directly. Otherwise, we need to iterate over the + * registered callers. + */ + if (ftrace_list == &ftrace_list_end || + ftrace_list->next == &ftrace_list_end) + func = ftrace_list->func; + else + func = ftrace_list_func; + + /* If we filter on pids, update to use the pid function */ + if (!list_empty(&ftrace_pids)) { + set_ftrace_pid_function(func); + func = ftrace_pid_func; + } +#ifdef CONFIG_HAVE_FUNCTION_TRACE_MCOUNT_TEST + ftrace_trace_function = func; +#else + __ftrace_trace_function = func; + ftrace_trace_function = ftrace_test_stop_func; +#endif +} + static int __register_ftrace_function(struct ftrace_ops *ops) { ops->next = ftrace_list; @@ -162,30 +190,8 @@ static int __register_ftrace_function(struct ftrace_ops *ops) */ rcu_assign_pointer(ftrace_list, ops); - if (ftrace_enabled) { - ftrace_func_t func; - - if (ops->next == &ftrace_list_end) - func = ops->func; - else - func = ftrace_list_func; - - if (!list_empty(&ftrace_pids)) { - set_ftrace_pid_function(func); - func = ftrace_pid_func; - } - - /* - * For one func, simply call it directly. - * For more than one func, call the chain. - */ -#ifdef CONFIG_HAVE_FUNCTION_TRACE_MCOUNT_TEST - ftrace_trace_function = func; -#else - __ftrace_trace_function = func; - ftrace_trace_function = ftrace_test_stop_func; -#endif - } + if (ftrace_enabled) + update_ftrace_function(); return 0; } @@ -213,52 +219,19 @@ static int __unregister_ftrace_function(struct ftrace_ops *ops) *p = (*p)->next; - if (ftrace_enabled) { - /* If we only have one func left, then call that directly */ - if (ftrace_list->next == &ftrace_list_end) { - ftrace_func_t func = ftrace_list->func; - - if (!list_empty(&ftrace_pids)) { - set_ftrace_pid_function(func); - func = ftrace_pid_func; - } -#ifdef CONFIG_HAVE_FUNCTION_TRACE_MCOUNT_TEST - ftrace_trace_function = func; -#else - __ftrace_trace_function = func; -#endif - } - } + if (ftrace_enabled) + update_ftrace_function(); return 0; } static void ftrace_update_pid_func(void) { - ftrace_func_t func; - + /* Only do something if we are tracing something */ if (ftrace_trace_function == ftrace_stub) return; -#ifdef CONFIG_HAVE_FUNCTION_TRACE_MCOUNT_TEST - func = ftrace_trace_function; -#else - func = __ftrace_trace_function; -#endif - - if (!list_empty(&ftrace_pids)) { - set_ftrace_pid_function(func); - func = ftrace_pid_func; - } else { - if (func == ftrace_pid_func) - func = ftrace_pid_function; - } - -#ifdef CONFIG_HAVE_FUNCTION_TRACE_MCOUNT_TEST - ftrace_trace_function = func; -#else - __ftrace_trace_function = func; -#endif + update_ftrace_function(); } #ifdef CONFIG_FUNCTION_PROFILER -- cgit v1.1 From b9df92d2a94eef8811061aecb1396290df440e2e Mon Sep 17 00:00:00 2001 From: Steven Rostedt Date: Thu, 28 Apr 2011 20:32:08 -0400 Subject: ftrace: Consolidate the function match routines for normal and mods The code used for matching functions is almost identical between normal selecting of functions and using the :mod: feature of set_ftrace_notrace. Consolidate the two users into one function. Signed-off-by: Steven Rostedt --- kernel/trace/ftrace.c | 98 +++++++++++++++++++-------------------------------- 1 file changed, 36 insertions(+), 62 deletions(-) (limited to 'kernel') diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c index 33bcc71..4f19dbb 100644 --- a/kernel/trace/ftrace.c +++ b/kernel/trace/ftrace.c @@ -1726,34 +1726,52 @@ update_record(struct dyn_ftrace *rec, unsigned long flag, int not) } static int -ftrace_match_record(struct dyn_ftrace *rec, char *regex, int len, int type) +ftrace_match_record(struct dyn_ftrace *rec, char *mod, + char *regex, int len, int type) { char str[KSYM_SYMBOL_LEN]; + char *modname; + + kallsyms_lookup(rec->ip, NULL, NULL, &modname, str); + + if (mod) { + /* module lookup requires matching the module */ + if (!modname || strcmp(modname, mod)) + return 0; + + /* blank search means to match all funcs in the mod */ + if (!len) + return 1; + } - kallsyms_lookup(rec->ip, NULL, NULL, NULL, str); return ftrace_match(str, regex, len, type); } -static int ftrace_match_records(char *buff, int len, int enable) +static int match_records(char *buff, int len, char *mod, int enable, int not) { - unsigned int search_len; + unsigned search_len = 0; struct ftrace_page *pg; struct dyn_ftrace *rec; + int type = MATCH_FULL; + char *search = buff; unsigned long flag; - char *search; - int type; - int not; int found = 0; - flag = enable ? FTRACE_FL_FILTER : FTRACE_FL_NOTRACE; - type = filter_parse_regex(buff, len, &search, ¬); + if (len) { + type = filter_parse_regex(buff, len, &search, ¬); + search_len = strlen(search); + } - search_len = strlen(search); + flag = enable ? FTRACE_FL_FILTER : FTRACE_FL_NOTRACE; mutex_lock(&ftrace_lock); + + if (unlikely(ftrace_disabled)) + goto out_unlock; + do_for_each_ftrace_rec(pg, rec) { - if (ftrace_match_record(rec, search, search_len, type)) { + if (ftrace_match_record(rec, mod, search, search_len, type)) { update_record(rec, flag, not); found = 1; } @@ -1763,43 +1781,23 @@ static int ftrace_match_records(char *buff, int len, int enable) */ if (enable && (rec->flags & FTRACE_FL_FILTER)) ftrace_filtered = 1; + } while_for_each_ftrace_rec(); + out_unlock: mutex_unlock(&ftrace_lock); return found; } static int -ftrace_match_module_record(struct dyn_ftrace *rec, char *mod, - char *regex, int len, int type) +ftrace_match_records(char *buff, int len, int enable) { - char str[KSYM_SYMBOL_LEN]; - char *modname; - - kallsyms_lookup(rec->ip, NULL, NULL, &modname, str); - - if (!modname || strcmp(modname, mod)) - return 0; - - /* blank search means to match all funcs in the mod */ - if (len) - return ftrace_match(str, regex, len, type); - else - return 1; + return match_records(buff, len, NULL, enable, 0); } static int ftrace_match_module_records(char *buff, char *mod, int enable) { - unsigned search_len = 0; - struct ftrace_page *pg; - struct dyn_ftrace *rec; - int type = MATCH_FULL; - char *search = buff; - unsigned long flag; int not = 0; - int found = 0; - - flag = enable ? FTRACE_FL_FILTER : FTRACE_FL_NOTRACE; /* blank or '*' mean the same */ if (strcmp(buff, "*") == 0) @@ -1811,31 +1809,7 @@ static int ftrace_match_module_records(char *buff, char *mod, int enable) not = 1; } - if (strlen(buff)) { - type = filter_parse_regex(buff, strlen(buff), &search, ¬); - search_len = strlen(search); - } - - mutex_lock(&ftrace_lock); - - if (unlikely(ftrace_disabled)) - goto out_unlock; - - do_for_each_ftrace_rec(pg, rec) { - - if (ftrace_match_module_record(rec, mod, - search, search_len, type)) { - update_record(rec, flag, not); - found = 1; - } - if (enable && (rec->flags & FTRACE_FL_FILTER)) - ftrace_filtered = 1; - - } while_for_each_ftrace_rec(); - out_unlock: - mutex_unlock(&ftrace_lock); - - return found; + return match_records(buff, strlen(buff), mod, enable, not); } /* @@ -1993,7 +1967,7 @@ register_ftrace_function_probe(char *glob, struct ftrace_probe_ops *ops, do_for_each_ftrace_rec(pg, rec) { - if (!ftrace_match_record(rec, search, len, type)) + if (!ftrace_match_record(rec, NULL, search, len, type)) continue; entry = kmalloc(sizeof(*entry), GFP_KERNEL); @@ -2548,7 +2522,7 @@ ftrace_set_func(unsigned long *array, int *idx, char *buffer) if (rec->flags & FTRACE_FL_FREE) continue; - if (ftrace_match_record(rec, search, search_len, type)) { + if (ftrace_match_record(rec, NULL, search, search_len, type)) { /* if it is in the array */ exists = false; for (i = 0; i < *idx; i++) { -- cgit v1.1 From c42321c76b0ef472e3bae4bfcb0f46ab19e038ef Mon Sep 17 00:00:00 2001 From: Thomas Gleixner Date: Mon, 2 May 2011 18:16:22 +0200 Subject: genirq: Make generic irq chip depend on CONFIG_GENERIC_IRQ_CHIP Only compile it in when there are users. Signed-off-by: Thomas Gleixner Cc: linux-arm-kernel@lists.infradead.org --- kernel/irq/Kconfig | 4 ++++ kernel/irq/Makefile | 2 +- 2 files changed, 5 insertions(+), 1 deletion(-) (limited to 'kernel') diff --git a/kernel/irq/Kconfig b/kernel/irq/Kconfig index c574f9a..d1d051b3 100644 --- a/kernel/irq/Kconfig +++ b/kernel/irq/Kconfig @@ -48,6 +48,10 @@ config IRQ_PREFLOW_FASTEOI config IRQ_EDGE_EOI_HANDLER bool +# Generic configurable interrupt chip implementation +config GENERIC_IRQ_CHIP + bool + # Support forced irq threading config IRQ_FORCED_THREADING bool diff --git a/kernel/irq/Makefile b/kernel/irq/Makefile index e7a13bd..7329005 100644 --- a/kernel/irq/Makefile +++ b/kernel/irq/Makefile @@ -1,6 +1,6 @@ obj-y := irqdesc.o handle.o manage.o spurious.o resend.o chip.o dummychip.o devres.o -obj-y += generic-chip.o +obj-$(CONFIG_GENERIC_IRQ_CHIP) += generic-chip.o obj-$(CONFIG_GENERIC_IRQ_PROBE) += autoprobe.o obj-$(CONFIG_PROC_FS) += proc.o obj-$(CONFIG_GENERIC_PENDING_IRQ) += migration.o -- cgit v1.1 From 94b2c363dcf732a4edab4ed66041cb36e7f28fbf Mon Sep 17 00:00:00 2001 From: Geert Uytterhoeven Date: Sat, 30 Apr 2011 22:56:20 +0200 Subject: genirq: Fix typo CONFIG_GENIRC_IRQ_SHOW_LEVEL commit ab7798ffcf98b11a9525cf65bacdae3fd58d357f ("genirq: Expand generic show_interrupts()") added the Kconfig option GENERIC_IRQ_SHOW_LEVEL to accomodate PowerPC, but this doesn't actually enable the functionality due to a typo in the #ifdef check. Signed-off-by: Geert Uytterhoeven Cc: Linux/PPC Development Link: http://lkml.kernel.org/r/%3Calpine.DEB.2.00.1104302251370.19068%40ayla.of.borg%3E Signed-off-by: Thomas Gleixner --- kernel/irq/proc.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'kernel') diff --git a/kernel/irq/proc.c b/kernel/irq/proc.c index dd201bd..834899f 100644 --- a/kernel/irq/proc.c +++ b/kernel/irq/proc.c @@ -419,7 +419,7 @@ int show_interrupts(struct seq_file *p, void *v) } else { seq_printf(p, " %8s", "None"); } -#ifdef CONFIG_GENIRC_IRQ_SHOW_LEVEL +#ifdef CONFIG_GENERIC_IRQ_SHOW_LEVEL seq_printf(p, " %-8s", irqd_is_level_type(&desc->irq_data) ? "Level" : "Edge"); #endif if (desc->name) -- cgit v1.1 From fae85b7c8bcc7de9c0a2698587e20c15beb7d5a6 Mon Sep 17 00:00:00 2001 From: Borislav Petkov Date: Tue, 26 Oct 2010 20:24:03 +0200 Subject: perf: Start the restructuring mv kernel/perf_event.c -> kernel/events/core.c. From there, all further sensible splitting can happen. The idea is that due to perf_event.c becoming pretty sizable and with the advent of the marriage with ftrace, splitting functionality into its logical parts should help speeding up the unification and to manage the complexity of the subsystem. Signed-off-by: Borislav Petkov --- kernel/Makefile | 5 +- kernel/events/Makefile | 5 + kernel/events/core.c | 7455 ++++++++++++++++++++++++++++++++++++++++++++++++ kernel/perf_event.c | 7455 ------------------------------------------------ 4 files changed, 7463 insertions(+), 7457 deletions(-) create mode 100644 kernel/events/Makefile create mode 100644 kernel/events/core.c delete mode 100644 kernel/perf_event.c (limited to 'kernel') diff --git a/kernel/Makefile b/kernel/Makefile index 85cbfb3..7981530 100644 --- a/kernel/Makefile +++ b/kernel/Makefile @@ -21,7 +21,6 @@ CFLAGS_REMOVE_mutex-debug.o = -pg CFLAGS_REMOVE_rtmutex-debug.o = -pg CFLAGS_REMOVE_cgroup-debug.o = -pg CFLAGS_REMOVE_sched_clock.o = -pg -CFLAGS_REMOVE_perf_event.o = -pg CFLAGS_REMOVE_irq_work.o = -pg endif @@ -103,7 +102,9 @@ obj-$(CONFIG_RING_BUFFER) += trace/ obj-$(CONFIG_TRACEPOINTS) += trace/ obj-$(CONFIG_SMP) += sched_cpupri.o obj-$(CONFIG_IRQ_WORK) += irq_work.o -obj-$(CONFIG_PERF_EVENTS) += perf_event.o + +obj-$(CONFIG_PERF_EVENTS) += events/ + obj-$(CONFIG_HAVE_HW_BREAKPOINT) += hw_breakpoint.o obj-$(CONFIG_USER_RETURN_NOTIFIER) += user-return-notifier.o obj-$(CONFIG_PADATA) += padata.o diff --git a/kernel/events/Makefile b/kernel/events/Makefile new file mode 100644 index 0000000..26c00e4 --- /dev/null +++ b/kernel/events/Makefile @@ -0,0 +1,5 @@ +ifdef CONFIG_FUNCTION_TRACER +CFLAGS_REMOVE_core.o = -pg +endif + +obj-y += core.o diff --git a/kernel/events/core.c b/kernel/events/core.c new file mode 100644 index 0000000..440bc48 --- /dev/null +++ b/kernel/events/core.c @@ -0,0 +1,7455 @@ +/* + * Performance events core code: + * + * Copyright (C) 2008 Thomas Gleixner + * Copyright (C) 2008-2009 Red Hat, Inc., Ingo Molnar + * Copyright (C) 2008-2009 Red Hat, Inc., Peter Zijlstra + * Copyright © 2009 Paul Mackerras, IBM Corp. + * + * For licensing details see kernel-base/COPYING + */ + +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include + +#include + +struct remote_function_call { + struct task_struct *p; + int (*func)(void *info); + void *info; + int ret; +}; + +static void remote_function(void *data) +{ + struct remote_function_call *tfc = data; + struct task_struct *p = tfc->p; + + if (p) { + tfc->ret = -EAGAIN; + if (task_cpu(p) != smp_processor_id() || !task_curr(p)) + return; + } + + tfc->ret = tfc->func(tfc->info); +} + +/** + * task_function_call - call a function on the cpu on which a task runs + * @p: the task to evaluate + * @func: the function to be called + * @info: the function call argument + * + * Calls the function @func when the task is currently running. This might + * be on the current CPU, which just calls the function directly + * + * returns: @func return value, or + * -ESRCH - when the process isn't running + * -EAGAIN - when the process moved away + */ +static int +task_function_call(struct task_struct *p, int (*func) (void *info), void *info) +{ + struct remote_function_call data = { + .p = p, + .func = func, + .info = info, + .ret = -ESRCH, /* No such (running) process */ + }; + + if (task_curr(p)) + smp_call_function_single(task_cpu(p), remote_function, &data, 1); + + return data.ret; +} + +/** + * cpu_function_call - call a function on the cpu + * @func: the function to be called + * @info: the function call argument + * + * Calls the function @func on the remote cpu. + * + * returns: @func return value or -ENXIO when the cpu is offline + */ +static int cpu_function_call(int cpu, int (*func) (void *info), void *info) +{ + struct remote_function_call data = { + .p = NULL, + .func = func, + .info = info, + .ret = -ENXIO, /* No such CPU */ + }; + + smp_call_function_single(cpu, remote_function, &data, 1); + + return data.ret; +} + +#define PERF_FLAG_ALL (PERF_FLAG_FD_NO_GROUP |\ + PERF_FLAG_FD_OUTPUT |\ + PERF_FLAG_PID_CGROUP) + +enum event_type_t { + EVENT_FLEXIBLE = 0x1, + EVENT_PINNED = 0x2, + EVENT_ALL = EVENT_FLEXIBLE | EVENT_PINNED, +}; + +/* + * perf_sched_events : >0 events exist + * perf_cgroup_events: >0 per-cpu cgroup events exist on this cpu + */ +struct jump_label_key perf_sched_events __read_mostly; +static DEFINE_PER_CPU(atomic_t, perf_cgroup_events); + +static atomic_t nr_mmap_events __read_mostly; +static atomic_t nr_comm_events __read_mostly; +static atomic_t nr_task_events __read_mostly; + +static LIST_HEAD(pmus); +static DEFINE_MUTEX(pmus_lock); +static struct srcu_struct pmus_srcu; + +/* + * perf event paranoia level: + * -1 - not paranoid at all + * 0 - disallow raw tracepoint access for unpriv + * 1 - disallow cpu events for unpriv + * 2 - disallow kernel profiling for unpriv + */ +int sysctl_perf_event_paranoid __read_mostly = 1; + +/* Minimum for 512 kiB + 1 user control page */ +int sysctl_perf_event_mlock __read_mostly = 512 + (PAGE_SIZE / 1024); /* 'free' kiB per user */ + +/* + * max perf event sample rate + */ +#define DEFAULT_MAX_SAMPLE_RATE 100000 +int sysctl_perf_event_sample_rate __read_mostly = DEFAULT_MAX_SAMPLE_RATE; +static int max_samples_per_tick __read_mostly = + DIV_ROUND_UP(DEFAULT_MAX_SAMPLE_RATE, HZ); + +int perf_proc_update_handler(struct ctl_table *table, int write, + void __user *buffer, size_t *lenp, + loff_t *ppos) +{ + int ret = proc_dointvec(table, write, buffer, lenp, ppos); + + if (ret || !write) + return ret; + + max_samples_per_tick = DIV_ROUND_UP(sysctl_perf_event_sample_rate, HZ); + + return 0; +} + +static atomic64_t perf_event_id; + +static void cpu_ctx_sched_out(struct perf_cpu_context *cpuctx, + enum event_type_t event_type); + +static void cpu_ctx_sched_in(struct perf_cpu_context *cpuctx, + enum event_type_t event_type, + struct task_struct *task); + +static void update_context_time(struct perf_event_context *ctx); +static u64 perf_event_time(struct perf_event *event); + +void __weak perf_event_print_debug(void) { } + +extern __weak const char *perf_pmu_name(void) +{ + return "pmu"; +} + +static inline u64 perf_clock(void) +{ + return local_clock(); +} + +static inline struct perf_cpu_context * +__get_cpu_context(struct perf_event_context *ctx) +{ + return this_cpu_ptr(ctx->pmu->pmu_cpu_context); +} + +#ifdef CONFIG_CGROUP_PERF + +/* + * Must ensure cgroup is pinned (css_get) before calling + * this function. In other words, we cannot call this function + * if there is no cgroup event for the current CPU context. + */ +static inline struct perf_cgroup * +perf_cgroup_from_task(struct task_struct *task) +{ + return container_of(task_subsys_state(task, perf_subsys_id), + struct perf_cgroup, css); +} + +static inline bool +perf_cgroup_match(struct perf_event *event) +{ + struct perf_event_context *ctx = event->ctx; + struct perf_cpu_context *cpuctx = __get_cpu_context(ctx); + + return !event->cgrp || event->cgrp == cpuctx->cgrp; +} + +static inline void perf_get_cgroup(struct perf_event *event) +{ + css_get(&event->cgrp->css); +} + +static inline void perf_put_cgroup(struct perf_event *event) +{ + css_put(&event->cgrp->css); +} + +static inline void perf_detach_cgroup(struct perf_event *event) +{ + perf_put_cgroup(event); + event->cgrp = NULL; +} + +static inline int is_cgroup_event(struct perf_event *event) +{ + return event->cgrp != NULL; +} + +static inline u64 perf_cgroup_event_time(struct perf_event *event) +{ + struct perf_cgroup_info *t; + + t = per_cpu_ptr(event->cgrp->info, event->cpu); + return t->time; +} + +static inline void __update_cgrp_time(struct perf_cgroup *cgrp) +{ + struct perf_cgroup_info *info; + u64 now; + + now = perf_clock(); + + info = this_cpu_ptr(cgrp->info); + + info->time += now - info->timestamp; + info->timestamp = now; +} + +static inline void update_cgrp_time_from_cpuctx(struct perf_cpu_context *cpuctx) +{ + struct perf_cgroup *cgrp_out = cpuctx->cgrp; + if (cgrp_out) + __update_cgrp_time(cgrp_out); +} + +static inline void update_cgrp_time_from_event(struct perf_event *event) +{ + struct perf_cgroup *cgrp; + + /* + * ensure we access cgroup data only when needed and + * when we know the cgroup is pinned (css_get) + */ + if (!is_cgroup_event(event)) + return; + + cgrp = perf_cgroup_from_task(current); + /* + * Do not update time when cgroup is not active + */ + if (cgrp == event->cgrp) + __update_cgrp_time(event->cgrp); +} + +static inline void +perf_cgroup_set_timestamp(struct task_struct *task, + struct perf_event_context *ctx) +{ + struct perf_cgroup *cgrp; + struct perf_cgroup_info *info; + + /* + * ctx->lock held by caller + * ensure we do not access cgroup data + * unless we have the cgroup pinned (css_get) + */ + if (!task || !ctx->nr_cgroups) + return; + + cgrp = perf_cgroup_from_task(task); + info = this_cpu_ptr(cgrp->info); + info->timestamp = ctx->timestamp; +} + +#define PERF_CGROUP_SWOUT 0x1 /* cgroup switch out every event */ +#define PERF_CGROUP_SWIN 0x2 /* cgroup switch in events based on task */ + +/* + * reschedule events based on the cgroup constraint of task. + * + * mode SWOUT : schedule out everything + * mode SWIN : schedule in based on cgroup for next + */ +void perf_cgroup_switch(struct task_struct *task, int mode) +{ + struct perf_cpu_context *cpuctx; + struct pmu *pmu; + unsigned long flags; + + /* + * disable interrupts to avoid geting nr_cgroup + * changes via __perf_event_disable(). Also + * avoids preemption. + */ + local_irq_save(flags); + + /* + * we reschedule only in the presence of cgroup + * constrained events. + */ + rcu_read_lock(); + + list_for_each_entry_rcu(pmu, &pmus, entry) { + + cpuctx = this_cpu_ptr(pmu->pmu_cpu_context); + + perf_pmu_disable(cpuctx->ctx.pmu); + + /* + * perf_cgroup_events says at least one + * context on this CPU has cgroup events. + * + * ctx->nr_cgroups reports the number of cgroup + * events for a context. + */ + if (cpuctx->ctx.nr_cgroups > 0) { + + if (mode & PERF_CGROUP_SWOUT) { + cpu_ctx_sched_out(cpuctx, EVENT_ALL); + /* + * must not be done before ctxswout due + * to event_filter_match() in event_sched_out() + */ + cpuctx->cgrp = NULL; + } + + if (mode & PERF_CGROUP_SWIN) { + WARN_ON_ONCE(cpuctx->cgrp); + /* set cgrp before ctxsw in to + * allow event_filter_match() to not + * have to pass task around + */ + cpuctx->cgrp = perf_cgroup_from_task(task); + cpu_ctx_sched_in(cpuctx, EVENT_ALL, task); + } + } + + perf_pmu_enable(cpuctx->ctx.pmu); + } + + rcu_read_unlock(); + + local_irq_restore(flags); +} + +static inline void perf_cgroup_sched_out(struct task_struct *task) +{ + perf_cgroup_switch(task, PERF_CGROUP_SWOUT); +} + +static inline void perf_cgroup_sched_in(struct task_struct *task) +{ + perf_cgroup_switch(task, PERF_CGROUP_SWIN); +} + +static inline int perf_cgroup_connect(int fd, struct perf_event *event, + struct perf_event_attr *attr, + struct perf_event *group_leader) +{ + struct perf_cgroup *cgrp; + struct cgroup_subsys_state *css; + struct file *file; + int ret = 0, fput_needed; + + file = fget_light(fd, &fput_needed); + if (!file) + return -EBADF; + + css = cgroup_css_from_dir(file, perf_subsys_id); + if (IS_ERR(css)) { + ret = PTR_ERR(css); + goto out; + } + + cgrp = container_of(css, struct perf_cgroup, css); + event->cgrp = cgrp; + + /* must be done before we fput() the file */ + perf_get_cgroup(event); + + /* + * all events in a group must monitor + * the same cgroup because a task belongs + * to only one perf cgroup at a time + */ + if (group_leader && group_leader->cgrp != cgrp) { + perf_detach_cgroup(event); + ret = -EINVAL; + } +out: + fput_light(file, fput_needed); + return ret; +} + +static inline void +perf_cgroup_set_shadow_time(struct perf_event *event, u64 now) +{ + struct perf_cgroup_info *t; + t = per_cpu_ptr(event->cgrp->info, event->cpu); + event->shadow_ctx_time = now - t->timestamp; +} + +static inline void +perf_cgroup_defer_enabled(struct perf_event *event) +{ + /* + * when the current task's perf cgroup does not match + * the event's, we need to remember to call the + * perf_mark_enable() function the first time a task with + * a matching perf cgroup is scheduled in. + */ + if (is_cgroup_event(event) && !perf_cgroup_match(event)) + event->cgrp_defer_enabled = 1; +} + +static inline void +perf_cgroup_mark_enabled(struct perf_event *event, + struct perf_event_context *ctx) +{ + struct perf_event *sub; + u64 tstamp = perf_event_time(event); + + if (!event->cgrp_defer_enabled) + return; + + event->cgrp_defer_enabled = 0; + + event->tstamp_enabled = tstamp - event->total_time_enabled; + list_for_each_entry(sub, &event->sibling_list, group_entry) { + if (sub->state >= PERF_EVENT_STATE_INACTIVE) { + sub->tstamp_enabled = tstamp - sub->total_time_enabled; + sub->cgrp_defer_enabled = 0; + } + } +} +#else /* !CONFIG_CGROUP_PERF */ + +static inline bool +perf_cgroup_match(struct perf_event *event) +{ + return true; +} + +static inline void perf_detach_cgroup(struct perf_event *event) +{} + +static inline int is_cgroup_event(struct perf_event *event) +{ + return 0; +} + +static inline u64 perf_cgroup_event_cgrp_time(struct perf_event *event) +{ + return 0; +} + +static inline void update_cgrp_time_from_event(struct perf_event *event) +{ +} + +static inline void update_cgrp_time_from_cpuctx(struct perf_cpu_context *cpuctx) +{ +} + +static inline void perf_cgroup_sched_out(struct task_struct *task) +{ +} + +static inline void perf_cgroup_sched_in(struct task_struct *task) +{ +} + +static inline int perf_cgroup_connect(pid_t pid, struct perf_event *event, + struct perf_event_attr *attr, + struct perf_event *group_leader) +{ + return -EINVAL; +} + +static inline void +perf_cgroup_set_timestamp(struct task_struct *task, + struct perf_event_context *ctx) +{ +} + +void +perf_cgroup_switch(struct task_struct *task, struct task_struct *next) +{ +} + +static inline void +perf_cgroup_set_shadow_time(struct perf_event *event, u64 now) +{ +} + +static inline u64 perf_cgroup_event_time(struct perf_event *event) +{ + return 0; +} + +static inline void +perf_cgroup_defer_enabled(struct perf_event *event) +{ +} + +static inline void +perf_cgroup_mark_enabled(struct perf_event *event, + struct perf_event_context *ctx) +{ +} +#endif + +void perf_pmu_disable(struct pmu *pmu) +{ + int *count = this_cpu_ptr(pmu->pmu_disable_count); + if (!(*count)++) + pmu->pmu_disable(pmu); +} + +void perf_pmu_enable(struct pmu *pmu) +{ + int *count = this_cpu_ptr(pmu->pmu_disable_count); + if (!--(*count)) + pmu->pmu_enable(pmu); +} + +static DEFINE_PER_CPU(struct list_head, rotation_list); + +/* + * perf_pmu_rotate_start() and perf_rotate_context() are fully serialized + * because they're strictly cpu affine and rotate_start is called with IRQs + * disabled, while rotate_context is called from IRQ context. + */ +static void perf_pmu_rotate_start(struct pmu *pmu) +{ + struct perf_cpu_context *cpuctx = this_cpu_ptr(pmu->pmu_cpu_context); + struct list_head *head = &__get_cpu_var(rotation_list); + + WARN_ON(!irqs_disabled()); + + if (list_empty(&cpuctx->rotation_list)) + list_add(&cpuctx->rotation_list, head); +} + +static void get_ctx(struct perf_event_context *ctx) +{ + WARN_ON(!atomic_inc_not_zero(&ctx->refcount)); +} + +static void free_ctx(struct rcu_head *head) +{ + struct perf_event_context *ctx; + + ctx = container_of(head, struct perf_event_context, rcu_head); + kfree(ctx); +} + +static void put_ctx(struct perf_event_context *ctx) +{ + if (atomic_dec_and_test(&ctx->refcount)) { + if (ctx->parent_ctx) + put_ctx(ctx->parent_ctx); + if (ctx->task) + put_task_struct(ctx->task); + call_rcu(&ctx->rcu_head, free_ctx); + } +} + +static void unclone_ctx(struct perf_event_context *ctx) +{ + if (ctx->parent_ctx) { + put_ctx(ctx->parent_ctx); + ctx->parent_ctx = NULL; + } +} + +static u32 perf_event_pid(struct perf_event *event, struct task_struct *p) +{ + /* + * only top level events have the pid namespace they were created in + */ + if (event->parent) + event = event->parent; + + return task_tgid_nr_ns(p, event->ns); +} + +static u32 perf_event_tid(struct perf_event *event, struct task_struct *p) +{ + /* + * only top level events have the pid namespace they were created in + */ + if (event->parent) + event = event->parent; + + return task_pid_nr_ns(p, event->ns); +} + +/* + * If we inherit events we want to return the parent event id + * to userspace. + */ +static u64 primary_event_id(struct perf_event *event) +{ + u64 id = event->id; + + if (event->parent) + id = event->parent->id; + + return id; +} + +/* + * Get the perf_event_context for a task and lock it. + * This has to cope with with the fact that until it is locked, + * the context could get moved to another task. + */ +static struct perf_event_context * +perf_lock_task_context(struct task_struct *task, int ctxn, unsigned long *flags) +{ + struct perf_event_context *ctx; + + rcu_read_lock(); +retry: + ctx = rcu_dereference(task->perf_event_ctxp[ctxn]); + if (ctx) { + /* + * If this context is a clone of another, it might + * get swapped for another underneath us by + * perf_event_task_sched_out, though the + * rcu_read_lock() protects us from any context + * getting freed. Lock the context and check if it + * got swapped before we could get the lock, and retry + * if so. If we locked the right context, then it + * can't get swapped on us any more. + */ + raw_spin_lock_irqsave(&ctx->lock, *flags); + if (ctx != rcu_dereference(task->perf_event_ctxp[ctxn])) { + raw_spin_unlock_irqrestore(&ctx->lock, *flags); + goto retry; + } + + if (!atomic_inc_not_zero(&ctx->refcount)) { + raw_spin_unlock_irqrestore(&ctx->lock, *flags); + ctx = NULL; + } + } + rcu_read_unlock(); + return ctx; +} + +/* + * Get the context for a task and increment its pin_count so it + * can't get swapped to another task. This also increments its + * reference count so that the context can't get freed. + */ +static struct perf_event_context * +perf_pin_task_context(struct task_struct *task, int ctxn) +{ + struct perf_event_context *ctx; + unsigned long flags; + + ctx = perf_lock_task_context(task, ctxn, &flags); + if (ctx) { + ++ctx->pin_count; + raw_spin_unlock_irqrestore(&ctx->lock, flags); + } + return ctx; +} + +static void perf_unpin_context(struct perf_event_context *ctx) +{ + unsigned long flags; + + raw_spin_lock_irqsave(&ctx->lock, flags); + --ctx->pin_count; + raw_spin_unlock_irqrestore(&ctx->lock, flags); +} + +/* + * Update the record of the current time in a context. + */ +static void update_context_time(struct perf_event_context *ctx) +{ + u64 now = perf_clock(); + + ctx->time += now - ctx->timestamp; + ctx->timestamp = now; +} + +static u64 perf_event_time(struct perf_event *event) +{ + struct perf_event_context *ctx = event->ctx; + + if (is_cgroup_event(event)) + return perf_cgroup_event_time(event); + + return ctx ? ctx->time : 0; +} + +/* + * Update the total_time_enabled and total_time_running fields for a event. + */ +static void update_event_times(struct perf_event *event) +{ + struct perf_event_context *ctx = event->ctx; + u64 run_end; + + if (event->state < PERF_EVENT_STATE_INACTIVE || + event->group_leader->state < PERF_EVENT_STATE_INACTIVE) + return; + /* + * in cgroup mode, time_enabled represents + * the time the event was enabled AND active + * tasks were in the monitored cgroup. This is + * independent of the activity of the context as + * there may be a mix of cgroup and non-cgroup events. + * + * That is why we treat cgroup events differently + * here. + */ + if (is_cgroup_event(event)) + run_end = perf_event_time(event); + else if (ctx->is_active) + run_end = ctx->time; + else + run_end = event->tstamp_stopped; + + event->total_time_enabled = run_end - event->tstamp_enabled; + + if (event->state == PERF_EVENT_STATE_INACTIVE) + run_end = event->tstamp_stopped; + else + run_end = perf_event_time(event); + + event->total_time_running = run_end - event->tstamp_running; + +} + +/* + * Update total_time_enabled and total_time_running for all events in a group. + */ +static void update_group_times(struct perf_event *leader) +{ + struct perf_event *event; + + update_event_times(leader); + list_for_each_entry(event, &leader->sibling_list, group_entry) + update_event_times(event); +} + +static struct list_head * +ctx_group_list(struct perf_event *event, struct perf_event_context *ctx) +{ + if (event->attr.pinned) + return &ctx->pinned_groups; + else + return &ctx->flexible_groups; +} + +/* + * Add a event from the lists for its context. + * Must be called with ctx->mutex and ctx->lock held. + */ +static void +list_add_event(struct perf_event *event, struct perf_event_context *ctx) +{ + WARN_ON_ONCE(event->attach_state & PERF_ATTACH_CONTEXT); + event->attach_state |= PERF_ATTACH_CONTEXT; + + /* + * If we're a stand alone event or group leader, we go to the context + * list, group events are kept attached to the group so that + * perf_group_detach can, at all times, locate all siblings. + */ + if (event->group_leader == event) { + struct list_head *list; + + if (is_software_event(event)) + event->group_flags |= PERF_GROUP_SOFTWARE; + + list = ctx_group_list(event, ctx); + list_add_tail(&event->group_entry, list); + } + + if (is_cgroup_event(event)) + ctx->nr_cgroups++; + + list_add_rcu(&event->event_entry, &ctx->event_list); + if (!ctx->nr_events) + perf_pmu_rotate_start(ctx->pmu); + ctx->nr_events++; + if (event->attr.inherit_stat) + ctx->nr_stat++; +} + +/* + * Called at perf_event creation and when events are attached/detached from a + * group. + */ +static void perf_event__read_size(struct perf_event *event) +{ + int entry = sizeof(u64); /* value */ + int size = 0; + int nr = 1; + + if (event->attr.read_format & PERF_FORMAT_TOTAL_TIME_ENABLED) + size += sizeof(u64); + + if (event->attr.read_format & PERF_FORMAT_TOTAL_TIME_RUNNING) + size += sizeof(u64); + + if (event->attr.read_format & PERF_FORMAT_ID) + entry += sizeof(u64); + + if (event->attr.read_format & PERF_FORMAT_GROUP) { + nr += event->group_leader->nr_siblings; + size += sizeof(u64); + } + + size += entry * nr; + event->read_size = size; +} + +static void perf_event__header_size(struct perf_event *event) +{ + struct perf_sample_data *data; + u64 sample_type = event->attr.sample_type; + u16 size = 0; + + perf_event__read_size(event); + + if (sample_type & PERF_SAMPLE_IP) + size += sizeof(data->ip); + + if (sample_type & PERF_SAMPLE_ADDR) + size += sizeof(data->addr); + + if (sample_type & PERF_SAMPLE_PERIOD) + size += sizeof(data->period); + + if (sample_type & PERF_SAMPLE_READ) + size += event->read_size; + + event->header_size = size; +} + +static void perf_event__id_header_size(struct perf_event *event) +{ + struct perf_sample_data *data; + u64 sample_type = event->attr.sample_type; + u16 size = 0; + + if (sample_type & PERF_SAMPLE_TID) + size += sizeof(data->tid_entry); + + if (sample_type & PERF_SAMPLE_TIME) + size += sizeof(data->time); + + if (sample_type & PERF_SAMPLE_ID) + size += sizeof(data->id); + + if (sample_type & PERF_SAMPLE_STREAM_ID) + size += sizeof(data->stream_id); + + if (sample_type & PERF_SAMPLE_CPU) + size += sizeof(data->cpu_entry); + + event->id_header_size = size; +} + +static void perf_group_attach(struct perf_event *event) +{ + struct perf_event *group_leader = event->group_leader, *pos; + + /* + * We can have double attach due to group movement in perf_event_open. + */ + if (event->attach_state & PERF_ATTACH_GROUP) + return; + + event->attach_state |= PERF_ATTACH_GROUP; + + if (group_leader == event) + return; + + if (group_leader->group_flags & PERF_GROUP_SOFTWARE && + !is_software_event(event)) + group_leader->group_flags &= ~PERF_GROUP_SOFTWARE; + + list_add_tail(&event->group_entry, &group_leader->sibling_list); + group_leader->nr_siblings++; + + perf_event__header_size(group_leader); + + list_for_each_entry(pos, &group_leader->sibling_list, group_entry) + perf_event__header_size(pos); +} + +/* + * Remove a event from the lists for its context. + * Must be called with ctx->mutex and ctx->lock held. + */ +static void +list_del_event(struct perf_event *event, struct perf_event_context *ctx) +{ + struct perf_cpu_context *cpuctx; + /* + * We can have double detach due to exit/hot-unplug + close. + */ + if (!(event->attach_state & PERF_ATTACH_CONTEXT)) + return; + + event->attach_state &= ~PERF_ATTACH_CONTEXT; + + if (is_cgroup_event(event)) { + ctx->nr_cgroups--; + cpuctx = __get_cpu_context(ctx); + /* + * if there are no more cgroup events + * then cler cgrp to avoid stale pointer + * in update_cgrp_time_from_cpuctx() + */ + if (!ctx->nr_cgroups) + cpuctx->cgrp = NULL; + } + + ctx->nr_events--; + if (event->attr.inherit_stat) + ctx->nr_stat--; + + list_del_rcu(&event->event_entry); + + if (event->group_leader == event) + list_del_init(&event->group_entry); + + update_group_times(event); + + /* + * If event was in error state, then keep it + * that way, otherwise bogus counts will be + * returned on read(). The only way to get out + * of error state is by explicit re-enabling + * of the event + */ + if (event->state > PERF_EVENT_STATE_OFF) + event->state = PERF_EVENT_STATE_OFF; +} + +static void perf_group_detach(struct perf_event *event) +{ + struct perf_event *sibling, *tmp; + struct list_head *list = NULL; + + /* + * We can have double detach due to exit/hot-unplug + close. + */ + if (!(event->attach_state & PERF_ATTACH_GROUP)) + return; + + event->attach_state &= ~PERF_ATTACH_GROUP; + + /* + * If this is a sibling, remove it from its group. + */ + if (event->group_leader != event) { + list_del_init(&event->group_entry); + event->group_leader->nr_siblings--; + goto out; + } + + if (!list_empty(&event->group_entry)) + list = &event->group_entry; + + /* + * If this was a group event with sibling events then + * upgrade the siblings to singleton events by adding them + * to whatever list we are on. + */ + list_for_each_entry_safe(sibling, tmp, &event->sibling_list, group_entry) { + if (list) + list_move_tail(&sibling->group_entry, list); + sibling->group_leader = sibling; + + /* Inherit group flags from the previous leader */ + sibling->group_flags = event->group_flags; + } + +out: + perf_event__header_size(event->group_leader); + + list_for_each_entry(tmp, &event->group_leader->sibling_list, group_entry) + perf_event__header_size(tmp); +} + +static inline int +event_filter_match(struct perf_event *event) +{ + return (event->cpu == -1 || event->cpu == smp_processor_id()) + && perf_cgroup_match(event); +} + +static void +event_sched_out(struct perf_event *event, + struct perf_cpu_context *cpuctx, + struct perf_event_context *ctx) +{ + u64 tstamp = perf_event_time(event); + u64 delta; + /* + * An event which could not be activated because of + * filter mismatch still needs to have its timings + * maintained, otherwise bogus information is return + * via read() for time_enabled, time_running: + */ + if (event->state == PERF_EVENT_STATE_INACTIVE + && !event_filter_match(event)) { + delta = tstamp - event->tstamp_stopped; + event->tstamp_running += delta; + event->tstamp_stopped = tstamp; + } + + if (event->state != PERF_EVENT_STATE_ACTIVE) + return; + + event->state = PERF_EVENT_STATE_INACTIVE; + if (event->pending_disable) { + event->pending_disable = 0; + event->state = PERF_EVENT_STATE_OFF; + } + event->tstamp_stopped = tstamp; + event->pmu->del(event, 0); + event->oncpu = -1; + + if (!is_software_event(event)) + cpuctx->active_oncpu--; + ctx->nr_active--; + if (event->attr.exclusive || !cpuctx->active_oncpu) + cpuctx->exclusive = 0; +} + +static void +group_sched_out(struct perf_event *group_event, + struct perf_cpu_context *cpuctx, + struct perf_event_context *ctx) +{ + struct perf_event *event; + int state = group_event->state; + + event_sched_out(group_event, cpuctx, ctx); + + /* + * Schedule out siblings (if any): + */ + list_for_each_entry(event, &group_event->sibling_list, group_entry) + event_sched_out(event, cpuctx, ctx); + + if (state == PERF_EVENT_STATE_ACTIVE && group_event->attr.exclusive) + cpuctx->exclusive = 0; +} + +/* + * Cross CPU call to remove a performance event + * + * We disable the event on the hardware level first. After that we + * remove it from the context list. + */ +static int __perf_remove_from_context(void *info) +{ + struct perf_event *event = info; + struct perf_event_context *ctx = event->ctx; + struct perf_cpu_context *cpuctx = __get_cpu_context(ctx); + + raw_spin_lock(&ctx->lock); + event_sched_out(event, cpuctx, ctx); + list_del_event(event, ctx); + raw_spin_unlock(&ctx->lock); + + return 0; +} + + +/* + * Remove the event from a task's (or a CPU's) list of events. + * + * CPU events are removed with a smp call. For task events we only + * call when the task is on a CPU. + * + * If event->ctx is a cloned context, callers must make sure that + * every task struct that event->ctx->task could possibly point to + * remains valid. This is OK when called from perf_release since + * that only calls us on the top-level context, which can't be a clone. + * When called from perf_event_exit_task, it's OK because the + * context has been detached from its task. + */ +static void perf_remove_from_context(struct perf_event *event) +{ + struct perf_event_context *ctx = event->ctx; + struct task_struct *task = ctx->task; + + lockdep_assert_held(&ctx->mutex); + + if (!task) { + /* + * Per cpu events are removed via an smp call and + * the removal is always successful. + */ + cpu_function_call(event->cpu, __perf_remove_from_context, event); + return; + } + +retry: + if (!task_function_call(task, __perf_remove_from_context, event)) + return; + + raw_spin_lock_irq(&ctx->lock); + /* + * If we failed to find a running task, but find the context active now + * that we've acquired the ctx->lock, retry. + */ + if (ctx->is_active) { + raw_spin_unlock_irq(&ctx->lock); + goto retry; + } + + /* + * Since the task isn't running, its safe to remove the event, us + * holding the ctx->lock ensures the task won't get scheduled in. + */ + list_del_event(event, ctx); + raw_spin_unlock_irq(&ctx->lock); +} + +/* + * Cross CPU call to disable a performance event + */ +static int __perf_event_disable(void *info) +{ + struct perf_event *event = info; + struct perf_event_context *ctx = event->ctx; + struct perf_cpu_context *cpuctx = __get_cpu_context(ctx); + + /* + * If this is a per-task event, need to check whether this + * event's task is the current task on this cpu. + * + * Can trigger due to concurrent perf_event_context_sched_out() + * flipping contexts around. + */ + if (ctx->task && cpuctx->task_ctx != ctx) + return -EINVAL; + + raw_spin_lock(&ctx->lock); + + /* + * If the event is on, turn it off. + * If it is in error state, leave it in error state. + */ + if (event->state >= PERF_EVENT_STATE_INACTIVE) { + update_context_time(ctx); + update_cgrp_time_from_event(event); + update_group_times(event); + if (event == event->group_leader) + group_sched_out(event, cpuctx, ctx); + else + event_sched_out(event, cpuctx, ctx); + event->state = PERF_EVENT_STATE_OFF; + } + + raw_spin_unlock(&ctx->lock); + + return 0; +} + +/* + * Disable a event. + * + * If event->ctx is a cloned context, callers must make sure that + * every task struct that event->ctx->task could possibly point to + * remains valid. This condition is satisifed when called through + * perf_event_for_each_child or perf_event_for_each because they + * hold the top-level event's child_mutex, so any descendant that + * goes to exit will block in sync_child_event. + * When called from perf_pending_event it's OK because event->ctx + * is the current context on this CPU and preemption is disabled, + * hence we can't get into perf_event_task_sched_out for this context. + */ +void perf_event_disable(struct perf_event *event) +{ + struct perf_event_context *ctx = event->ctx; + struct task_struct *task = ctx->task; + + if (!task) { + /* + * Disable the event on the cpu that it's on + */ + cpu_function_call(event->cpu, __perf_event_disable, event); + return; + } + +retry: + if (!task_function_call(task, __perf_event_disable, event)) + return; + + raw_spin_lock_irq(&ctx->lock); + /* + * If the event is still active, we need to retry the cross-call. + */ + if (event->state == PERF_EVENT_STATE_ACTIVE) { + raw_spin_unlock_irq(&ctx->lock); + /* + * Reload the task pointer, it might have been changed by + * a concurrent perf_event_context_sched_out(). + */ + task = ctx->task; + goto retry; + } + + /* + * Since we have the lock this context can't be scheduled + * in, so we can change the state safely. + */ + if (event->state == PERF_EVENT_STATE_INACTIVE) { + update_group_times(event); + event->state = PERF_EVENT_STATE_OFF; + } + raw_spin_unlock_irq(&ctx->lock); +} + +static void perf_set_shadow_time(struct perf_event *event, + struct perf_event_context *ctx, + u64 tstamp) +{ + /* + * use the correct time source for the time snapshot + * + * We could get by without this by leveraging the + * fact that to get to this function, the caller + * has most likely already called update_context_time() + * and update_cgrp_time_xx() and thus both timestamp + * are identical (or very close). Given that tstamp is, + * already adjusted for cgroup, we could say that: + * tstamp - ctx->timestamp + * is equivalent to + * tstamp - cgrp->timestamp. + * + * Then, in perf_output_read(), the calculation would + * work with no changes because: + * - event is guaranteed scheduled in + * - no scheduled out in between + * - thus the timestamp would be the same + * + * But this is a bit hairy. + * + * So instead, we have an explicit cgroup call to remain + * within the time time source all along. We believe it + * is cleaner and simpler to understand. + */ + if (is_cgroup_event(event)) + perf_cgroup_set_shadow_time(event, tstamp); + else + event->shadow_ctx_time = tstamp - ctx->timestamp; +} + +#define MAX_INTERRUPTS (~0ULL) + +static void perf_log_throttle(struct perf_event *event, int enable); + +static int +event_sched_in(struct perf_event *event, + struct perf_cpu_context *cpuctx, + struct perf_event_context *ctx) +{ + u64 tstamp = perf_event_time(event); + + if (event->state <= PERF_EVENT_STATE_OFF) + return 0; + + event->state = PERF_EVENT_STATE_ACTIVE; + event->oncpu = smp_processor_id(); + + /* + * Unthrottle events, since we scheduled we might have missed several + * ticks already, also for a heavily scheduling task there is little + * guarantee it'll get a tick in a timely manner. + */ + if (unlikely(event->hw.interrupts == MAX_INTERRUPTS)) { + perf_log_throttle(event, 1); + event->hw.interrupts = 0; + } + + /* + * The new state must be visible before we turn it on in the hardware: + */ + smp_wmb(); + + if (event->pmu->add(event, PERF_EF_START)) { + event->state = PERF_EVENT_STATE_INACTIVE; + event->oncpu = -1; + return -EAGAIN; + } + + event->tstamp_running += tstamp - event->tstamp_stopped; + + perf_set_shadow_time(event, ctx, tstamp); + + if (!is_software_event(event)) + cpuctx->active_oncpu++; + ctx->nr_active++; + + if (event->attr.exclusive) + cpuctx->exclusive = 1; + + return 0; +} + +static int +group_sched_in(struct perf_event *group_event, + struct perf_cpu_context *cpuctx, + struct perf_event_context *ctx) +{ + struct perf_event *event, *partial_group = NULL; + struct pmu *pmu = group_event->pmu; + u64 now = ctx->time; + bool simulate = false; + + if (group_event->state == PERF_EVENT_STATE_OFF) + return 0; + + pmu->start_txn(pmu); + + if (event_sched_in(group_event, cpuctx, ctx)) { + pmu->cancel_txn(pmu); + return -EAGAIN; + } + + /* + * Schedule in siblings as one group (if any): + */ + list_for_each_entry(event, &group_event->sibling_list, group_entry) { + if (event_sched_in(event, cpuctx, ctx)) { + partial_group = event; + goto group_error; + } + } + + if (!pmu->commit_txn(pmu)) + return 0; + +group_error: + /* + * Groups can be scheduled in as one unit only, so undo any + * partial group before returning: + * The events up to the failed event are scheduled out normally, + * tstamp_stopped will be updated. + * + * The failed events and the remaining siblings need to have + * their timings updated as if they had gone thru event_sched_in() + * and event_sched_out(). This is required to get consistent timings + * across the group. This also takes care of the case where the group + * could never be scheduled by ensuring tstamp_stopped is set to mark + * the time the event was actually stopped, such that time delta + * calculation in update_event_times() is correct. + */ + list_for_each_entry(event, &group_event->sibling_list, group_entry) { + if (event == partial_group) + simulate = true; + + if (simulate) { + event->tstamp_running += now - event->tstamp_stopped; + event->tstamp_stopped = now; + } else { + event_sched_out(event, cpuctx, ctx); + } + } + event_sched_out(group_event, cpuctx, ctx); + + pmu->cancel_txn(pmu); + + return -EAGAIN; +} + +/* + * Work out whether we can put this event group on the CPU now. + */ +static int group_can_go_on(struct perf_event *event, + struct perf_cpu_context *cpuctx, + int can_add_hw) +{ + /* + * Groups consisting entirely of software events can always go on. + */ + if (event->group_flags & PERF_GROUP_SOFTWARE) + return 1; + /* + * If an exclusive group is already on, no other hardware + * events can go on. + */ + if (cpuctx->exclusive) + return 0; + /* + * If this group is exclusive and there are already + * events on the CPU, it can't go on. + */ + if (event->attr.exclusive && cpuctx->active_oncpu) + return 0; + /* + * Otherwise, try to add it if all previous groups were able + * to go on. + */ + return can_add_hw; +} + +static void add_event_to_ctx(struct perf_event *event, + struct perf_event_context *ctx) +{ + u64 tstamp = perf_event_time(event); + + list_add_event(event, ctx); + perf_group_attach(event); + event->tstamp_enabled = tstamp; + event->tstamp_running = tstamp; + event->tstamp_stopped = tstamp; +} + +static void perf_event_context_sched_in(struct perf_event_context *ctx, + struct task_struct *tsk); + +/* + * Cross CPU call to install and enable a performance event + * + * Must be called with ctx->mutex held + */ +static int __perf_install_in_context(void *info) +{ + struct perf_event *event = info; + struct perf_event_context *ctx = event->ctx; + struct perf_event *leader = event->group_leader; + struct perf_cpu_context *cpuctx = __get_cpu_context(ctx); + int err; + + /* + * In case we're installing a new context to an already running task, + * could also happen before perf_event_task_sched_in() on architectures + * which do context switches with IRQs enabled. + */ + if (ctx->task && !cpuctx->task_ctx) + perf_event_context_sched_in(ctx, ctx->task); + + raw_spin_lock(&ctx->lock); + ctx->is_active = 1; + update_context_time(ctx); + /* + * update cgrp time only if current cgrp + * matches event->cgrp. Must be done before + * calling add_event_to_ctx() + */ + update_cgrp_time_from_event(event); + + add_event_to_ctx(event, ctx); + + if (!event_filter_match(event)) + goto unlock; + + /* + * Don't put the event on if it is disabled or if + * it is in a group and the group isn't on. + */ + if (event->state != PERF_EVENT_STATE_INACTIVE || + (leader != event && leader->state != PERF_EVENT_STATE_ACTIVE)) + goto unlock; + + /* + * An exclusive event can't go on if there are already active + * hardware events, and no hardware event can go on if there + * is already an exclusive event on. + */ + if (!group_can_go_on(event, cpuctx, 1)) + err = -EEXIST; + else + err = event_sched_in(event, cpuctx, ctx); + + if (err) { + /* + * This event couldn't go on. If it is in a group + * then we have to pull the whole group off. + * If the event group is pinned then put it in error state. + */ + if (leader != event) + group_sched_out(leader, cpuctx, ctx); + if (leader->attr.pinned) { + update_group_times(leader); + leader->state = PERF_EVENT_STATE_ERROR; + } + } + +unlock: + raw_spin_unlock(&ctx->lock); + + return 0; +} + +/* + * Attach a performance event to a context + * + * First we add the event to the list with the hardware enable bit + * in event->hw_config cleared. + * + * If the event is attached to a task which is on a CPU we use a smp + * call to enable it in the task context. The task might have been + * scheduled away, but we check this in the smp call again. + */ +static void +perf_install_in_context(struct perf_event_context *ctx, + struct perf_event *event, + int cpu) +{ + struct task_struct *task = ctx->task; + + lockdep_assert_held(&ctx->mutex); + + event->ctx = ctx; + + if (!task) { + /* + * Per cpu events are installed via an smp call and + * the install is always successful. + */ + cpu_function_call(cpu, __perf_install_in_context, event); + return; + } + +retry: + if (!task_function_call(task, __perf_install_in_context, event)) + return; + + raw_spin_lock_irq(&ctx->lock); + /* + * If we failed to find a running task, but find the context active now + * that we've acquired the ctx->lock, retry. + */ + if (ctx->is_active) { + raw_spin_unlock_irq(&ctx->lock); + goto retry; + } + + /* + * Since the task isn't running, its safe to add the event, us holding + * the ctx->lock ensures the task won't get scheduled in. + */ + add_event_to_ctx(event, ctx); + raw_spin_unlock_irq(&ctx->lock); +} + +/* + * Put a event into inactive state and update time fields. + * Enabling the leader of a group effectively enables all + * the group members that aren't explicitly disabled, so we + * have to update their ->tstamp_enabled also. + * Note: this works for group members as well as group leaders + * since the non-leader members' sibling_lists will be empty. + */ +static void __perf_event_mark_enabled(struct perf_event *event, + struct perf_event_context *ctx) +{ + struct perf_event *sub; + u64 tstamp = perf_event_time(event); + + event->state = PERF_EVENT_STATE_INACTIVE; + event->tstamp_enabled = tstamp - event->total_time_enabled; + list_for_each_entry(sub, &event->sibling_list, group_entry) { + if (sub->state >= PERF_EVENT_STATE_INACTIVE) + sub->tstamp_enabled = tstamp - sub->total_time_enabled; + } +} + +/* + * Cross CPU call to enable a performance event + */ +static int __perf_event_enable(void *info) +{ + struct perf_event *event = info; + struct perf_event_context *ctx = event->ctx; + struct perf_event *leader = event->group_leader; + struct perf_cpu_context *cpuctx = __get_cpu_context(ctx); + int err; + + if (WARN_ON_ONCE(!ctx->is_active)) + return -EINVAL; + + raw_spin_lock(&ctx->lock); + update_context_time(ctx); + + if (event->state >= PERF_EVENT_STATE_INACTIVE) + goto unlock; + + /* + * set current task's cgroup time reference point + */ + perf_cgroup_set_timestamp(current, ctx); + + __perf_event_mark_enabled(event, ctx); + + if (!event_filter_match(event)) { + if (is_cgroup_event(event)) + perf_cgroup_defer_enabled(event); + goto unlock; + } + + /* + * If the event is in a group and isn't the group leader, + * then don't put it on unless the group is on. + */ + if (leader != event && leader->state != PERF_EVENT_STATE_ACTIVE) + goto unlock; + + if (!group_can_go_on(event, cpuctx, 1)) { + err = -EEXIST; + } else { + if (event == leader) + err = group_sched_in(event, cpuctx, ctx); + else + err = event_sched_in(event, cpuctx, ctx); + } + + if (err) { + /* + * If this event can't go on and it's part of a + * group, then the whole group has to come off. + */ + if (leader != event) + group_sched_out(leader, cpuctx, ctx); + if (leader->attr.pinned) { + update_group_times(leader); + leader->state = PERF_EVENT_STATE_ERROR; + } + } + +unlock: + raw_spin_unlock(&ctx->lock); + + return 0; +} + +/* + * Enable a event. + * + * If event->ctx is a cloned context, callers must make sure that + * every task struct that event->ctx->task could possibly point to + * remains valid. This condition is satisfied when called through + * perf_event_for_each_child or perf_event_for_each as described + * for perf_event_disable. + */ +void perf_event_enable(struct perf_event *event) +{ + struct perf_event_context *ctx = event->ctx; + struct task_struct *task = ctx->task; + + if (!task) { + /* + * Enable the event on the cpu that it's on + */ + cpu_function_call(event->cpu, __perf_event_enable, event); + return; + } + + raw_spin_lock_irq(&ctx->lock); + if (event->state >= PERF_EVENT_STATE_INACTIVE) + goto out; + + /* + * If the event is in error state, clear that first. + * That way, if we see the event in error state below, we + * know that it has gone back into error state, as distinct + * from the task having been scheduled away before the + * cross-call arrived. + */ + if (event->state == PERF_EVENT_STATE_ERROR) + event->state = PERF_EVENT_STATE_OFF; + +retry: + if (!ctx->is_active) { + __perf_event_mark_enabled(event, ctx); + goto out; + } + + raw_spin_unlock_irq(&ctx->lock); + + if (!task_function_call(task, __perf_event_enable, event)) + return; + + raw_spin_lock_irq(&ctx->lock); + + /* + * If the context is active and the event is still off, + * we need to retry the cross-call. + */ + if (ctx->is_active && event->state == PERF_EVENT_STATE_OFF) { + /* + * task could have been flipped by a concurrent + * perf_event_context_sched_out() + */ + task = ctx->task; + goto retry; + } + +out: + raw_spin_unlock_irq(&ctx->lock); +} + +static int perf_event_refresh(struct perf_event *event, int refresh) +{ + /* + * not supported on inherited events + */ + if (event->attr.inherit || !is_sampling_event(event)) + return -EINVAL; + + atomic_add(refresh, &event->event_limit); + perf_event_enable(event); + + return 0; +} + +static void ctx_sched_out(struct perf_event_context *ctx, + struct perf_cpu_context *cpuctx, + enum event_type_t event_type) +{ + struct perf_event *event; + + raw_spin_lock(&ctx->lock); + perf_pmu_disable(ctx->pmu); + ctx->is_active = 0; + if (likely(!ctx->nr_events)) + goto out; + update_context_time(ctx); + update_cgrp_time_from_cpuctx(cpuctx); + + if (!ctx->nr_active) + goto out; + + if (event_type & EVENT_PINNED) { + list_for_each_entry(event, &ctx->pinned_groups, group_entry) + group_sched_out(event, cpuctx, ctx); + } + + if (event_type & EVENT_FLEXIBLE) { + list_for_each_entry(event, &ctx->flexible_groups, group_entry) + group_sched_out(event, cpuctx, ctx); + } +out: + perf_pmu_enable(ctx->pmu); + raw_spin_unlock(&ctx->lock); +} + +/* + * Test whether two contexts are equivalent, i.e. whether they + * have both been cloned from the same version of the same context + * and they both have the same number of enabled events. + * If the number of enabled events is the same, then the set + * of enabled events should be the same, because these are both + * inherited contexts, therefore we can't access individual events + * in them directly with an fd; we can only enable/disable all + * events via prctl, or enable/disable all events in a family + * via ioctl, which will have the same effect on both contexts. + */ +static int context_equiv(struct perf_event_context *ctx1, + struct perf_event_context *ctx2) +{ + return ctx1->parent_ctx && ctx1->parent_ctx == ctx2->parent_ctx + && ctx1->parent_gen == ctx2->parent_gen + && !ctx1->pin_count && !ctx2->pin_count; +} + +static void __perf_event_sync_stat(struct perf_event *event, + struct perf_event *next_event) +{ + u64 value; + + if (!event->attr.inherit_stat) + return; + + /* + * Update the event value, we cannot use perf_event_read() + * because we're in the middle of a context switch and have IRQs + * disabled, which upsets smp_call_function_single(), however + * we know the event must be on the current CPU, therefore we + * don't need to use it. + */ + switch (event->state) { + case PERF_EVENT_STATE_ACTIVE: + event->pmu->read(event); + /* fall-through */ + + case PERF_EVENT_STATE_INACTIVE: + update_event_times(event); + break; + + default: + break; + } + + /* + * In order to keep per-task stats reliable we need to flip the event + * values when we flip the contexts. + */ + value = local64_read(&next_event->count); + value = local64_xchg(&event->count, value); + local64_set(&next_event->count, value); + + swap(event->total_time_enabled, next_event->total_time_enabled); + swap(event->total_time_running, next_event->total_time_running); + + /* + * Since we swizzled the values, update the user visible data too. + */ + perf_event_update_userpage(event); + perf_event_update_userpage(next_event); +} + +#define list_next_entry(pos, member) \ + list_entry(pos->member.next, typeof(*pos), member) + +static void perf_event_sync_stat(struct perf_event_context *ctx, + struct perf_event_context *next_ctx) +{ + struct perf_event *event, *next_event; + + if (!ctx->nr_stat) + return; + + update_context_time(ctx); + + event = list_first_entry(&ctx->event_list, + struct perf_event, event_entry); + + next_event = list_first_entry(&next_ctx->event_list, + struct perf_event, event_entry); + + while (&event->event_entry != &ctx->event_list && + &next_event->event_entry != &next_ctx->event_list) { + + __perf_event_sync_stat(event, next_event); + + event = list_next_entry(event, event_entry); + next_event = list_next_entry(next_event, event_entry); + } +} + +static void perf_event_context_sched_out(struct task_struct *task, int ctxn, + struct task_struct *next) +{ + struct perf_event_context *ctx = task->perf_event_ctxp[ctxn]; + struct perf_event_context *next_ctx; + struct perf_event_context *parent; + struct perf_cpu_context *cpuctx; + int do_switch = 1; + + if (likely(!ctx)) + return; + + cpuctx = __get_cpu_context(ctx); + if (!cpuctx->task_ctx) + return; + + rcu_read_lock(); + parent = rcu_dereference(ctx->parent_ctx); + next_ctx = next->perf_event_ctxp[ctxn]; + if (parent && next_ctx && + rcu_dereference(next_ctx->parent_ctx) == parent) { + /* + * Looks like the two contexts are clones, so we might be + * able to optimize the context switch. We lock both + * contexts and check that they are clones under the + * lock (including re-checking that neither has been + * uncloned in the meantime). It doesn't matter which + * order we take the locks because no other cpu could + * be trying to lock both of these tasks. + */ + raw_spin_lock(&ctx->lock); + raw_spin_lock_nested(&next_ctx->lock, SINGLE_DEPTH_NESTING); + if (context_equiv(ctx, next_ctx)) { + /* + * XXX do we need a memory barrier of sorts + * wrt to rcu_dereference() of perf_event_ctxp + */ + task->perf_event_ctxp[ctxn] = next_ctx; + next->perf_event_ctxp[ctxn] = ctx; + ctx->task = next; + next_ctx->task = task; + do_switch = 0; + + perf_event_sync_stat(ctx, next_ctx); + } + raw_spin_unlock(&next_ctx->lock); + raw_spin_unlock(&ctx->lock); + } + rcu_read_unlock(); + + if (do_switch) { + ctx_sched_out(ctx, cpuctx, EVENT_ALL); + cpuctx->task_ctx = NULL; + } +} + +#define for_each_task_context_nr(ctxn) \ + for ((ctxn) = 0; (ctxn) < perf_nr_task_contexts; (ctxn)++) + +/* + * Called from scheduler to remove the events of the current task, + * with interrupts disabled. + * + * We stop each event and update the event value in event->count. + * + * This does not protect us against NMI, but disable() + * sets the disabled bit in the control field of event _before_ + * accessing the event control register. If a NMI hits, then it will + * not restart the event. + */ +void __perf_event_task_sched_out(struct task_struct *task, + struct task_struct *next) +{ + int ctxn; + + for_each_task_context_nr(ctxn) + perf_event_context_sched_out(task, ctxn, next); + + /* + * if cgroup events exist on this CPU, then we need + * to check if we have to switch out PMU state. + * cgroup event are system-wide mode only + */ + if (atomic_read(&__get_cpu_var(perf_cgroup_events))) + perf_cgroup_sched_out(task); +} + +static void task_ctx_sched_out(struct perf_event_context *ctx, + enum event_type_t event_type) +{ + struct perf_cpu_context *cpuctx = __get_cpu_context(ctx); + + if (!cpuctx->task_ctx) + return; + + if (WARN_ON_ONCE(ctx != cpuctx->task_ctx)) + return; + + ctx_sched_out(ctx, cpuctx, event_type); + cpuctx->task_ctx = NULL; +} + +/* + * Called with IRQs disabled + */ +static void cpu_ctx_sched_out(struct perf_cpu_context *cpuctx, + enum event_type_t event_type) +{ + ctx_sched_out(&cpuctx->ctx, cpuctx, event_type); +} + +static void +ctx_pinned_sched_in(struct perf_event_context *ctx, + struct perf_cpu_context *cpuctx) +{ + struct perf_event *event; + + list_for_each_entry(event, &ctx->pinned_groups, group_entry) { + if (event->state <= PERF_EVENT_STATE_OFF) + continue; + if (!event_filter_match(event)) + continue; + + /* may need to reset tstamp_enabled */ + if (is_cgroup_event(event)) + perf_cgroup_mark_enabled(event, ctx); + + if (group_can_go_on(event, cpuctx, 1)) + group_sched_in(event, cpuctx, ctx); + + /* + * If this pinned group hasn't been scheduled, + * put it in error state. + */ + if (event->state == PERF_EVENT_STATE_INACTIVE) { + update_group_times(event); + event->state = PERF_EVENT_STATE_ERROR; + } + } +} + +static void +ctx_flexible_sched_in(struct perf_event_context *ctx, + struct perf_cpu_context *cpuctx) +{ + struct perf_event *event; + int can_add_hw = 1; + + list_for_each_entry(event, &ctx->flexible_groups, group_entry) { + /* Ignore events in OFF or ERROR state */ + if (event->state <= PERF_EVENT_STATE_OFF) + continue; + /* + * Listen to the 'cpu' scheduling filter constraint + * of events: + */ + if (!event_filter_match(event)) + continue; + + /* may need to reset tstamp_enabled */ + if (is_cgroup_event(event)) + perf_cgroup_mark_enabled(event, ctx); + + if (group_can_go_on(event, cpuctx, can_add_hw)) { + if (group_sched_in(event, cpuctx, ctx)) + can_add_hw = 0; + } + } +} + +static void +ctx_sched_in(struct perf_event_context *ctx, + struct perf_cpu_context *cpuctx, + enum event_type_t event_type, + struct task_struct *task) +{ + u64 now; + + raw_spin_lock(&ctx->lock); + ctx->is_active = 1; + if (likely(!ctx->nr_events)) + goto out; + + now = perf_clock(); + ctx->timestamp = now; + perf_cgroup_set_timestamp(task, ctx); + /* + * First go through the list and put on any pinned groups + * in order to give them the best chance of going on. + */ + if (event_type & EVENT_PINNED) + ctx_pinned_sched_in(ctx, cpuctx); + + /* Then walk through the lower prio flexible groups */ + if (event_type & EVENT_FLEXIBLE) + ctx_flexible_sched_in(ctx, cpuctx); + +out: + raw_spin_unlock(&ctx->lock); +} + +static void cpu_ctx_sched_in(struct perf_cpu_context *cpuctx, + enum event_type_t event_type, + struct task_struct *task) +{ + struct perf_event_context *ctx = &cpuctx->ctx; + + ctx_sched_in(ctx, cpuctx, event_type, task); +} + +static void task_ctx_sched_in(struct perf_event_context *ctx, + enum event_type_t event_type) +{ + struct perf_cpu_context *cpuctx; + + cpuctx = __get_cpu_context(ctx); + if (cpuctx->task_ctx == ctx) + return; + + ctx_sched_in(ctx, cpuctx, event_type, NULL); + cpuctx->task_ctx = ctx; +} + +static void perf_event_context_sched_in(struct perf_event_context *ctx, + struct task_struct *task) +{ + struct perf_cpu_context *cpuctx; + + cpuctx = __get_cpu_context(ctx); + if (cpuctx->task_ctx == ctx) + return; + + perf_pmu_disable(ctx->pmu); + /* + * We want to keep the following priority order: + * cpu pinned (that don't need to move), task pinned, + * cpu flexible, task flexible. + */ + cpu_ctx_sched_out(cpuctx, EVENT_FLEXIBLE); + + ctx_sched_in(ctx, cpuctx, EVENT_PINNED, task); + cpu_ctx_sched_in(cpuctx, EVENT_FLEXIBLE, task); + ctx_sched_in(ctx, cpuctx, EVENT_FLEXIBLE, task); + + cpuctx->task_ctx = ctx; + + /* + * Since these rotations are per-cpu, we need to ensure the + * cpu-context we got scheduled on is actually rotating. + */ + perf_pmu_rotate_start(ctx->pmu); + perf_pmu_enable(ctx->pmu); +} + +/* + * Called from scheduler to add the events of the current task + * with interrupts disabled. + * + * We restore the event value and then enable it. + * + * This does not protect us against NMI, but enable() + * sets the enabled bit in the control field of event _before_ + * accessing the event control register. If a NMI hits, then it will + * keep the event running. + */ +void __perf_event_task_sched_in(struct task_struct *task) +{ + struct perf_event_context *ctx; + int ctxn; + + for_each_task_context_nr(ctxn) { + ctx = task->perf_event_ctxp[ctxn]; + if (likely(!ctx)) + continue; + + perf_event_context_sched_in(ctx, task); + } + /* + * if cgroup events exist on this CPU, then we need + * to check if we have to switch in PMU state. + * cgroup event are system-wide mode only + */ + if (atomic_read(&__get_cpu_var(perf_cgroup_events))) + perf_cgroup_sched_in(task); +} + +static u64 perf_calculate_period(struct perf_event *event, u64 nsec, u64 count) +{ + u64 frequency = event->attr.sample_freq; + u64 sec = NSEC_PER_SEC; + u64 divisor, dividend; + + int count_fls, nsec_fls, frequency_fls, sec_fls; + + count_fls = fls64(count); + nsec_fls = fls64(nsec); + frequency_fls = fls64(frequency); + sec_fls = 30; + + /* + * We got @count in @nsec, with a target of sample_freq HZ + * the target period becomes: + * + * @count * 10^9 + * period = ------------------- + * @nsec * sample_freq + * + */ + + /* + * Reduce accuracy by one bit such that @a and @b converge + * to a similar magnitude. + */ +#define REDUCE_FLS(a, b) \ +do { \ + if (a##_fls > b##_fls) { \ + a >>= 1; \ + a##_fls--; \ + } else { \ + b >>= 1; \ + b##_fls--; \ + } \ +} while (0) + + /* + * Reduce accuracy until either term fits in a u64, then proceed with + * the other, so that finally we can do a u64/u64 division. + */ + while (count_fls + sec_fls > 64 && nsec_fls + frequency_fls > 64) { + REDUCE_FLS(nsec, frequency); + REDUCE_FLS(sec, count); + } + + if (count_fls + sec_fls > 64) { + divisor = nsec * frequency; + + while (count_fls + sec_fls > 64) { + REDUCE_FLS(count, sec); + divisor >>= 1; + } + + dividend = count * sec; + } else { + dividend = count * sec; + + while (nsec_fls + frequency_fls > 64) { + REDUCE_FLS(nsec, frequency); + dividend >>= 1; + } + + divisor = nsec * frequency; + } + + if (!divisor) + return dividend; + + return div64_u64(dividend, divisor); +} + +static void perf_adjust_period(struct perf_event *event, u64 nsec, u64 count) +{ + struct hw_perf_event *hwc = &event->hw; + s64 period, sample_period; + s64 delta; + + period = perf_calculate_period(event, nsec, count); + + delta = (s64)(period - hwc->sample_period); + delta = (delta + 7) / 8; /* low pass filter */ + + sample_period = hwc->sample_period + delta; + + if (!sample_period) + sample_period = 1; + + hwc->sample_period = sample_period; + + if (local64_read(&hwc->period_left) > 8*sample_period) { + event->pmu->stop(event, PERF_EF_UPDATE); + local64_set(&hwc->period_left, 0); + event->pmu->start(event, PERF_EF_RELOAD); + } +} + +static void perf_ctx_adjust_freq(struct perf_event_context *ctx, u64 period) +{ + struct perf_event *event; + struct hw_perf_event *hwc; + u64 interrupts, now; + s64 delta; + + raw_spin_lock(&ctx->lock); + list_for_each_entry_rcu(event, &ctx->event_list, event_entry) { + if (event->state != PERF_EVENT_STATE_ACTIVE) + continue; + + if (!event_filter_match(event)) + continue; + + hwc = &event->hw; + + interrupts = hwc->interrupts; + hwc->interrupts = 0; + + /* + * unthrottle events on the tick + */ + if (interrupts == MAX_INTERRUPTS) { + perf_log_throttle(event, 1); + event->pmu->start(event, 0); + } + + if (!event->attr.freq || !event->attr.sample_freq) + continue; + + event->pmu->read(event); + now = local64_read(&event->count); + delta = now - hwc->freq_count_stamp; + hwc->freq_count_stamp = now; + + if (delta > 0) + perf_adjust_period(event, period, delta); + } + raw_spin_unlock(&ctx->lock); +} + +/* + * Round-robin a context's events: + */ +static void rotate_ctx(struct perf_event_context *ctx) +{ + raw_spin_lock(&ctx->lock); + + /* + * Rotate the first entry last of non-pinned groups. Rotation might be + * disabled by the inheritance code. + */ + if (!ctx->rotate_disable) + list_rotate_left(&ctx->flexible_groups); + + raw_spin_unlock(&ctx->lock); +} + +/* + * perf_pmu_rotate_start() and perf_rotate_context() are fully serialized + * because they're strictly cpu affine and rotate_start is called with IRQs + * disabled, while rotate_context is called from IRQ context. + */ +static void perf_rotate_context(struct perf_cpu_context *cpuctx) +{ + u64 interval = (u64)cpuctx->jiffies_interval * TICK_NSEC; + struct perf_event_context *ctx = NULL; + int rotate = 0, remove = 1; + + if (cpuctx->ctx.nr_events) { + remove = 0; + if (cpuctx->ctx.nr_events != cpuctx->ctx.nr_active) + rotate = 1; + } + + ctx = cpuctx->task_ctx; + if (ctx && ctx->nr_events) { + remove = 0; + if (ctx->nr_events != ctx->nr_active) + rotate = 1; + } + + perf_pmu_disable(cpuctx->ctx.pmu); + perf_ctx_adjust_freq(&cpuctx->ctx, interval); + if (ctx) + perf_ctx_adjust_freq(ctx, interval); + + if (!rotate) + goto done; + + cpu_ctx_sched_out(cpuctx, EVENT_FLEXIBLE); + if (ctx) + task_ctx_sched_out(ctx, EVENT_FLEXIBLE); + + rotate_ctx(&cpuctx->ctx); + if (ctx) + rotate_ctx(ctx); + + cpu_ctx_sched_in(cpuctx, EVENT_FLEXIBLE, current); + if (ctx) + task_ctx_sched_in(ctx, EVENT_FLEXIBLE); + +done: + if (remove) + list_del_init(&cpuctx->rotation_list); + + perf_pmu_enable(cpuctx->ctx.pmu); +} + +void perf_event_task_tick(void) +{ + struct list_head *head = &__get_cpu_var(rotation_list); + struct perf_cpu_context *cpuctx, *tmp; + + WARN_ON(!irqs_disabled()); + + list_for_each_entry_safe(cpuctx, tmp, head, rotation_list) { + if (cpuctx->jiffies_interval == 1 || + !(jiffies % cpuctx->jiffies_interval)) + perf_rotate_context(cpuctx); + } +} + +static int event_enable_on_exec(struct perf_event *event, + struct perf_event_context *ctx) +{ + if (!event->attr.enable_on_exec) + return 0; + + event->attr.enable_on_exec = 0; + if (event->state >= PERF_EVENT_STATE_INACTIVE) + return 0; + + __perf_event_mark_enabled(event, ctx); + + return 1; +} + +/* + * Enable all of a task's events that have been marked enable-on-exec. + * This expects task == current. + */ +static void perf_event_enable_on_exec(struct perf_event_context *ctx) +{ + struct perf_event *event; + unsigned long flags; + int enabled = 0; + int ret; + + local_irq_save(flags); + if (!ctx || !ctx->nr_events) + goto out; + + /* + * We must ctxsw out cgroup events to avoid conflict + * when invoking perf_task_event_sched_in() later on + * in this function. Otherwise we end up trying to + * ctxswin cgroup events which are already scheduled + * in. + */ + perf_cgroup_sched_out(current); + task_ctx_sched_out(ctx, EVENT_ALL); + + raw_spin_lock(&ctx->lock); + + list_for_each_entry(event, &ctx->pinned_groups, group_entry) { + ret = event_enable_on_exec(event, ctx); + if (ret) + enabled = 1; + } + + list_for_each_entry(event, &ctx->flexible_groups, group_entry) { + ret = event_enable_on_exec(event, ctx); + if (ret) + enabled = 1; + } + + /* + * Unclone this context if we enabled any event. + */ + if (enabled) + unclone_ctx(ctx); + + raw_spin_unlock(&ctx->lock); + + /* + * Also calls ctxswin for cgroup events, if any: + */ + perf_event_context_sched_in(ctx, ctx->task); +out: + local_irq_restore(flags); +} + +/* + * Cross CPU call to read the hardware event + */ +static void __perf_event_read(void *info) +{ + struct perf_event *event = info; + struct perf_event_context *ctx = event->ctx; + struct perf_cpu_context *cpuctx = __get_cpu_context(ctx); + + /* + * If this is a task context, we need to check whether it is + * the current task context of this cpu. If not it has been + * scheduled out before the smp call arrived. In that case + * event->count would have been updated to a recent sample + * when the event was scheduled out. + */ + if (ctx->task && cpuctx->task_ctx != ctx) + return; + + raw_spin_lock(&ctx->lock); + if (ctx->is_active) { + update_context_time(ctx); + update_cgrp_time_from_event(event); + } + update_event_times(event); + if (event->state == PERF_EVENT_STATE_ACTIVE) + event->pmu->read(event); + raw_spin_unlock(&ctx->lock); +} + +static inline u64 perf_event_count(struct perf_event *event) +{ + return local64_read(&event->count) + atomic64_read(&event->child_count); +} + +static u64 perf_event_read(struct perf_event *event) +{ + /* + * If event is enabled and currently active on a CPU, update the + * value in the event structure: + */ + if (event->state == PERF_EVENT_STATE_ACTIVE) { + smp_call_function_single(event->oncpu, + __perf_event_read, event, 1); + } else if (event->state == PERF_EVENT_STATE_INACTIVE) { + struct perf_event_context *ctx = event->ctx; + unsigned long flags; + + raw_spin_lock_irqsave(&ctx->lock, flags); + /* + * may read while context is not active + * (e.g., thread is blocked), in that case + * we cannot update context time + */ + if (ctx->is_active) { + update_context_time(ctx); + update_cgrp_time_from_event(event); + } + update_event_times(event); + raw_spin_unlock_irqrestore(&ctx->lock, flags); + } + + return perf_event_count(event); +} + +/* + * Callchain support + */ + +struct callchain_cpus_entries { + struct rcu_head rcu_head; + struct perf_callchain_entry *cpu_entries[0]; +}; + +static DEFINE_PER_CPU(int, callchain_recursion[PERF_NR_CONTEXTS]); +static atomic_t nr_callchain_events; +static DEFINE_MUTEX(callchain_mutex); +struct callchain_cpus_entries *callchain_cpus_entries; + + +__weak void perf_callchain_kernel(struct perf_callchain_entry *entry, + struct pt_regs *regs) +{ +} + +__weak void perf_callchain_user(struct perf_callchain_entry *entry, + struct pt_regs *regs) +{ +} + +static void release_callchain_buffers_rcu(struct rcu_head *head) +{ + struct callchain_cpus_entries *entries; + int cpu; + + entries = container_of(head, struct callchain_cpus_entries, rcu_head); + + for_each_possible_cpu(cpu) + kfree(entries->cpu_entries[cpu]); + + kfree(entries); +} + +static void release_callchain_buffers(void) +{ + struct callchain_cpus_entries *entries; + + entries = callchain_cpus_entries; + rcu_assign_pointer(callchain_cpus_entries, NULL); + call_rcu(&entries->rcu_head, release_callchain_buffers_rcu); +} + +static int alloc_callchain_buffers(void) +{ + int cpu; + int size; + struct callchain_cpus_entries *entries; + + /* + * We can't use the percpu allocation API for data that can be + * accessed from NMI. Use a temporary manual per cpu allocation + * until that gets sorted out. + */ + size = offsetof(struct callchain_cpus_entries, cpu_entries[nr_cpu_ids]); + + entries = kzalloc(size, GFP_KERNEL); + if (!entries) + return -ENOMEM; + + size = sizeof(struct perf_callchain_entry) * PERF_NR_CONTEXTS; + + for_each_possible_cpu(cpu) { + entries->cpu_entries[cpu] = kmalloc_node(size, GFP_KERNEL, + cpu_to_node(cpu)); + if (!entries->cpu_entries[cpu]) + goto fail; + } + + rcu_assign_pointer(callchain_cpus_entries, entries); + + return 0; + +fail: + for_each_possible_cpu(cpu) + kfree(entries->cpu_entries[cpu]); + kfree(entries); + + return -ENOMEM; +} + +static int get_callchain_buffers(void) +{ + int err = 0; + int count; + + mutex_lock(&callchain_mutex); + + count = atomic_inc_return(&nr_callchain_events); + if (WARN_ON_ONCE(count < 1)) { + err = -EINVAL; + goto exit; + } + + if (count > 1) { + /* If the allocation failed, give up */ + if (!callchain_cpus_entries) + err = -ENOMEM; + goto exit; + } + + err = alloc_callchain_buffers(); + if (err) + release_callchain_buffers(); +exit: + mutex_unlock(&callchain_mutex); + + return err; +} + +static void put_callchain_buffers(void) +{ + if (atomic_dec_and_mutex_lock(&nr_callchain_events, &callchain_mutex)) { + release_callchain_buffers(); + mutex_unlock(&callchain_mutex); + } +} + +static int get_recursion_context(int *recursion) +{ + int rctx; + + if (in_nmi()) + rctx = 3; + else if (in_irq()) + rctx = 2; + else if (in_softirq()) + rctx = 1; + else + rctx = 0; + + if (recursion[rctx]) + return -1; + + recursion[rctx]++; + barrier(); + + return rctx; +} + +static inline void put_recursion_context(int *recursion, int rctx) +{ + barrier(); + recursion[rctx]--; +} + +static struct perf_callchain_entry *get_callchain_entry(int *rctx) +{ + int cpu; + struct callchain_cpus_entries *entries; + + *rctx = get_recursion_context(__get_cpu_var(callchain_recursion)); + if (*rctx == -1) + return NULL; + + entries = rcu_dereference(callchain_cpus_entries); + if (!entries) + return NULL; + + cpu = smp_processor_id(); + + return &entries->cpu_entries[cpu][*rctx]; +} + +static void +put_callchain_entry(int rctx) +{ + put_recursion_context(__get_cpu_var(callchain_recursion), rctx); +} + +static struct perf_callchain_entry *perf_callchain(struct pt_regs *regs) +{ + int rctx; + struct perf_callchain_entry *entry; + + + entry = get_callchain_entry(&rctx); + if (rctx == -1) + return NULL; + + if (!entry) + goto exit_put; + + entry->nr = 0; + + if (!user_mode(regs)) { + perf_callchain_store(entry, PERF_CONTEXT_KERNEL); + perf_callchain_kernel(entry, regs); + if (current->mm) + regs = task_pt_regs(current); + else + regs = NULL; + } + + if (regs) { + perf_callchain_store(entry, PERF_CONTEXT_USER); + perf_callchain_user(entry, regs); + } + +exit_put: + put_callchain_entry(rctx); + + return entry; +} + +/* + * Initialize the perf_event context in a task_struct: + */ +static void __perf_event_init_context(struct perf_event_context *ctx) +{ + raw_spin_lock_init(&ctx->lock); + mutex_init(&ctx->mutex); + INIT_LIST_HEAD(&ctx->pinned_groups); + INIT_LIST_HEAD(&ctx->flexible_groups); + INIT_LIST_HEAD(&ctx->event_list); + atomic_set(&ctx->refcount, 1); +} + +static struct perf_event_context * +alloc_perf_context(struct pmu *pmu, struct task_struct *task) +{ + struct perf_event_context *ctx; + + ctx = kzalloc(sizeof(struct perf_event_context), GFP_KERNEL); + if (!ctx) + return NULL; + + __perf_event_init_context(ctx); + if (task) { + ctx->task = task; + get_task_struct(task); + } + ctx->pmu = pmu; + + return ctx; +} + +static struct task_struct * +find_lively_task_by_vpid(pid_t vpid) +{ + struct task_struct *task; + int err; + + rcu_read_lock(); + if (!vpid) + task = current; + else + task = find_task_by_vpid(vpid); + if (task) + get_task_struct(task); + rcu_read_unlock(); + + if (!task) + return ERR_PTR(-ESRCH); + + /* Reuse ptrace permission checks for now. */ + err = -EACCES; + if (!ptrace_may_access(task, PTRACE_MODE_READ)) + goto errout; + + return task; +errout: + put_task_struct(task); + return ERR_PTR(err); + +} + +/* + * Returns a matching context with refcount and pincount. + */ +static struct perf_event_context * +find_get_context(struct pmu *pmu, struct task_struct *task, int cpu) +{ + struct perf_event_context *ctx; + struct perf_cpu_context *cpuctx; + unsigned long flags; + int ctxn, err; + + if (!task) { + /* Must be root to operate on a CPU event: */ + if (perf_paranoid_cpu() && !capable(CAP_SYS_ADMIN)) + return ERR_PTR(-EACCES); + + /* + * We could be clever and allow to attach a event to an + * offline CPU and activate it when the CPU comes up, but + * that's for later. + */ + if (!cpu_online(cpu)) + return ERR_PTR(-ENODEV); + + cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu); + ctx = &cpuctx->ctx; + get_ctx(ctx); + ++ctx->pin_count; + + return ctx; + } + + err = -EINVAL; + ctxn = pmu->task_ctx_nr; + if (ctxn < 0) + goto errout; + +retry: + ctx = perf_lock_task_context(task, ctxn, &flags); + if (ctx) { + unclone_ctx(ctx); + ++ctx->pin_count; + raw_spin_unlock_irqrestore(&ctx->lock, flags); + } + + if (!ctx) { + ctx = alloc_perf_context(pmu, task); + err = -ENOMEM; + if (!ctx) + goto errout; + + get_ctx(ctx); + + err = 0; + mutex_lock(&task->perf_event_mutex); + /* + * If it has already passed perf_event_exit_task(). + * we must see PF_EXITING, it takes this mutex too. + */ + if (task->flags & PF_EXITING) + err = -ESRCH; + else if (task->perf_event_ctxp[ctxn]) + err = -EAGAIN; + else { + ++ctx->pin_count; + rcu_assign_pointer(task->perf_event_ctxp[ctxn], ctx); + } + mutex_unlock(&task->perf_event_mutex); + + if (unlikely(err)) { + put_task_struct(task); + kfree(ctx); + + if (err == -EAGAIN) + goto retry; + goto errout; + } + } + + return ctx; + +errout: + return ERR_PTR(err); +} + +static void perf_event_free_filter(struct perf_event *event); + +static void free_event_rcu(struct rcu_head *head) +{ + struct perf_event *event; + + event = container_of(head, struct perf_event, rcu_head); + if (event->ns) + put_pid_ns(event->ns); + perf_event_free_filter(event); + kfree(event); +} + +static void perf_buffer_put(struct perf_buffer *buffer); + +static void free_event(struct perf_event *event) +{ + irq_work_sync(&event->pending); + + if (!event->parent) { + if (event->attach_state & PERF_ATTACH_TASK) + jump_label_dec(&perf_sched_events); + if (event->attr.mmap || event->attr.mmap_data) + atomic_dec(&nr_mmap_events); + if (event->attr.comm) + atomic_dec(&nr_comm_events); + if (event->attr.task) + atomic_dec(&nr_task_events); + if (event->attr.sample_type & PERF_SAMPLE_CALLCHAIN) + put_callchain_buffers(); + if (is_cgroup_event(event)) { + atomic_dec(&per_cpu(perf_cgroup_events, event->cpu)); + jump_label_dec(&perf_sched_events); + } + } + + if (event->buffer) { + perf_buffer_put(event->buffer); + event->buffer = NULL; + } + + if (is_cgroup_event(event)) + perf_detach_cgroup(event); + + if (event->destroy) + event->destroy(event); + + if (event->ctx) + put_ctx(event->ctx); + + call_rcu(&event->rcu_head, free_event_rcu); +} + +int perf_event_release_kernel(struct perf_event *event) +{ + struct perf_event_context *ctx = event->ctx; + + /* + * Remove from the PMU, can't get re-enabled since we got + * here because the last ref went. + */ + perf_event_disable(event); + + WARN_ON_ONCE(ctx->parent_ctx); + /* + * There are two ways this annotation is useful: + * + * 1) there is a lock recursion from perf_event_exit_task + * see the comment there. + * + * 2) there is a lock-inversion with mmap_sem through + * perf_event_read_group(), which takes faults while + * holding ctx->mutex, however this is called after + * the last filedesc died, so there is no possibility + * to trigger the AB-BA case. + */ + mutex_lock_nested(&ctx->mutex, SINGLE_DEPTH_NESTING); + raw_spin_lock_irq(&ctx->lock); + perf_group_detach(event); + list_del_event(event, ctx); + raw_spin_unlock_irq(&ctx->lock); + mutex_unlock(&ctx->mutex); + + free_event(event); + + return 0; +} +EXPORT_SYMBOL_GPL(perf_event_release_kernel); + +/* + * Called when the last reference to the file is gone. + */ +static int perf_release(struct inode *inode, struct file *file) +{ + struct perf_event *event = file->private_data; + struct task_struct *owner; + + file->private_data = NULL; + + rcu_read_lock(); + owner = ACCESS_ONCE(event->owner); + /* + * Matches the smp_wmb() in perf_event_exit_task(). If we observe + * !owner it means the list deletion is complete and we can indeed + * free this event, otherwise we need to serialize on + * owner->perf_event_mutex. + */ + smp_read_barrier_depends(); + if (owner) { + /* + * Since delayed_put_task_struct() also drops the last + * task reference we can safely take a new reference + * while holding the rcu_read_lock(). + */ + get_task_struct(owner); + } + rcu_read_unlock(); + + if (owner) { + mutex_lock(&owner->perf_event_mutex); + /* + * We have to re-check the event->owner field, if it is cleared + * we raced with perf_event_exit_task(), acquiring the mutex + * ensured they're done, and we can proceed with freeing the + * event. + */ + if (event->owner) + list_del_init(&event->owner_entry); + mutex_unlock(&owner->perf_event_mutex); + put_task_struct(owner); + } + + return perf_event_release_kernel(event); +} + +u64 perf_event_read_value(struct perf_event *event, u64 *enabled, u64 *running) +{ + struct perf_event *child; + u64 total = 0; + + *enabled = 0; + *running = 0; + + mutex_lock(&event->child_mutex); + total += perf_event_read(event); + *enabled += event->total_time_enabled + + atomic64_read(&event->child_total_time_enabled); + *running += event->total_time_running + + atomic64_read(&event->child_total_time_running); + + list_for_each_entry(child, &event->child_list, child_list) { + total += perf_event_read(child); + *enabled += child->total_time_enabled; + *running += child->total_time_running; + } + mutex_unlock(&event->child_mutex); + + return total; +} +EXPORT_SYMBOL_GPL(perf_event_read_value); + +static int perf_event_read_group(struct perf_event *event, + u64 read_format, char __user *buf) +{ + struct perf_event *leader = event->group_leader, *sub; + int n = 0, size = 0, ret = -EFAULT; + struct perf_event_context *ctx = leader->ctx; + u64 values[5]; + u64 count, enabled, running; + + mutex_lock(&ctx->mutex); + count = perf_event_read_value(leader, &enabled, &running); + + values[n++] = 1 + leader->nr_siblings; + if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED) + values[n++] = enabled; + if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING) + values[n++] = running; + values[n++] = count; + if (read_format & PERF_FORMAT_ID) + values[n++] = primary_event_id(leader); + + size = n * sizeof(u64); + + if (copy_to_user(buf, values, size)) + goto unlock; + + ret = size; + + list_for_each_entry(sub, &leader->sibling_list, group_entry) { + n = 0; + + values[n++] = perf_event_read_value(sub, &enabled, &running); + if (read_format & PERF_FORMAT_ID) + values[n++] = primary_event_id(sub); + + size = n * sizeof(u64); + + if (copy_to_user(buf + ret, values, size)) { + ret = -EFAULT; + goto unlock; + } + + ret += size; + } +unlock: + mutex_unlock(&ctx->mutex); + + return ret; +} + +static int perf_event_read_one(struct perf_event *event, + u64 read_format, char __user *buf) +{ + u64 enabled, running; + u64 values[4]; + int n = 0; + + values[n++] = perf_event_read_value(event, &enabled, &running); + if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED) + values[n++] = enabled; + if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING) + values[n++] = running; + if (read_format & PERF_FORMAT_ID) + values[n++] = primary_event_id(event); + + if (copy_to_user(buf, values, n * sizeof(u64))) + return -EFAULT; + + return n * sizeof(u64); +} + +/* + * Read the performance event - simple non blocking version for now + */ +static ssize_t +perf_read_hw(struct perf_event *event, char __user *buf, size_t count) +{ + u64 read_format = event->attr.read_format; + int ret; + + /* + * Return end-of-file for a read on a event that is in + * error state (i.e. because it was pinned but it couldn't be + * scheduled on to the CPU at some point). + */ + if (event->state == PERF_EVENT_STATE_ERROR) + return 0; + + if (count < event->read_size) + return -ENOSPC; + + WARN_ON_ONCE(event->ctx->parent_ctx); + if (read_format & PERF_FORMAT_GROUP) + ret = perf_event_read_group(event, read_format, buf); + else + ret = perf_event_read_one(event, read_format, buf); + + return ret; +} + +static ssize_t +perf_read(struct file *file, char __user *buf, size_t count, loff_t *ppos) +{ + struct perf_event *event = file->private_data; + + return perf_read_hw(event, buf, count); +} + +static unsigned int perf_poll(struct file *file, poll_table *wait) +{ + struct perf_event *event = file->private_data; + struct perf_buffer *buffer; + unsigned int events = POLL_HUP; + + rcu_read_lock(); + buffer = rcu_dereference(event->buffer); + if (buffer) + events = atomic_xchg(&buffer->poll, 0); + rcu_read_unlock(); + + poll_wait(file, &event->waitq, wait); + + return events; +} + +static void perf_event_reset(struct perf_event *event) +{ + (void)perf_event_read(event); + local64_set(&event->count, 0); + perf_event_update_userpage(event); +} + +/* + * Holding the top-level event's child_mutex means that any + * descendant process that has inherited this event will block + * in sync_child_event if it goes to exit, thus satisfying the + * task existence requirements of perf_event_enable/disable. + */ +static void perf_event_for_each_child(struct perf_event *event, + void (*func)(struct perf_event *)) +{ + struct perf_event *child; + + WARN_ON_ONCE(event->ctx->parent_ctx); + mutex_lock(&event->child_mutex); + func(event); + list_for_each_entry(child, &event->child_list, child_list) + func(child); + mutex_unlock(&event->child_mutex); +} + +static void perf_event_for_each(struct perf_event *event, + void (*func)(struct perf_event *)) +{ + struct perf_event_context *ctx = event->ctx; + struct perf_event *sibling; + + WARN_ON_ONCE(ctx->parent_ctx); + mutex_lock(&ctx->mutex); + event = event->group_leader; + + perf_event_for_each_child(event, func); + func(event); + list_for_each_entry(sibling, &event->sibling_list, group_entry) + perf_event_for_each_child(event, func); + mutex_unlock(&ctx->mutex); +} + +static int perf_event_period(struct perf_event *event, u64 __user *arg) +{ + struct perf_event_context *ctx = event->ctx; + int ret = 0; + u64 value; + + if (!is_sampling_event(event)) + return -EINVAL; + + if (copy_from_user(&value, arg, sizeof(value))) + return -EFAULT; + + if (!value) + return -EINVAL; + + raw_spin_lock_irq(&ctx->lock); + if (event->attr.freq) { + if (value > sysctl_perf_event_sample_rate) { + ret = -EINVAL; + goto unlock; + } + + event->attr.sample_freq = value; + } else { + event->attr.sample_period = value; + event->hw.sample_period = value; + } +unlock: + raw_spin_unlock_irq(&ctx->lock); + + return ret; +} + +static const struct file_operations perf_fops; + +static struct perf_event *perf_fget_light(int fd, int *fput_needed) +{ + struct file *file; + + file = fget_light(fd, fput_needed); + if (!file) + return ERR_PTR(-EBADF); + + if (file->f_op != &perf_fops) { + fput_light(file, *fput_needed); + *fput_needed = 0; + return ERR_PTR(-EBADF); + } + + return file->private_data; +} + +static int perf_event_set_output(struct perf_event *event, + struct perf_event *output_event); +static int perf_event_set_filter(struct perf_event *event, void __user *arg); + +static long perf_ioctl(struct file *file, unsigned int cmd, unsigned long arg) +{ + struct perf_event *event = file->private_data; + void (*func)(struct perf_event *); + u32 flags = arg; + + switch (cmd) { + case PERF_EVENT_IOC_ENABLE: + func = perf_event_enable; + break; + case PERF_EVENT_IOC_DISABLE: + func = perf_event_disable; + break; + case PERF_EVENT_IOC_RESET: + func = perf_event_reset; + break; + + case PERF_EVENT_IOC_REFRESH: + return perf_event_refresh(event, arg); + + case PERF_EVENT_IOC_PERIOD: + return perf_event_period(event, (u64 __user *)arg); + + case PERF_EVENT_IOC_SET_OUTPUT: + { + struct perf_event *output_event = NULL; + int fput_needed = 0; + int ret; + + if (arg != -1) { + output_event = perf_fget_light(arg, &fput_needed); + if (IS_ERR(output_event)) + return PTR_ERR(output_event); + } + + ret = perf_event_set_output(event, output_event); + if (output_event) + fput_light(output_event->filp, fput_needed); + + return ret; + } + + case PERF_EVENT_IOC_SET_FILTER: + return perf_event_set_filter(event, (void __user *)arg); + + default: + return -ENOTTY; + } + + if (flags & PERF_IOC_FLAG_GROUP) + perf_event_for_each(event, func); + else + perf_event_for_each_child(event, func); + + return 0; +} + +int perf_event_task_enable(void) +{ + struct perf_event *event; + + mutex_lock(¤t->perf_event_mutex); + list_for_each_entry(event, ¤t->perf_event_list, owner_entry) + perf_event_for_each_child(event, perf_event_enable); + mutex_unlock(¤t->perf_event_mutex); + + return 0; +} + +int perf_event_task_disable(void) +{ + struct perf_event *event; + + mutex_lock(¤t->perf_event_mutex); + list_for_each_entry(event, ¤t->perf_event_list, owner_entry) + perf_event_for_each_child(event, perf_event_disable); + mutex_unlock(¤t->perf_event_mutex); + + return 0; +} + +#ifndef PERF_EVENT_INDEX_OFFSET +# define PERF_EVENT_INDEX_OFFSET 0 +#endif + +static int perf_event_index(struct perf_event *event) +{ + if (event->hw.state & PERF_HES_STOPPED) + return 0; + + if (event->state != PERF_EVENT_STATE_ACTIVE) + return 0; + + return event->hw.idx + 1 - PERF_EVENT_INDEX_OFFSET; +} + +/* + * Callers need to ensure there can be no nesting of this function, otherwise + * the seqlock logic goes bad. We can not serialize this because the arch + * code calls this from NMI context. + */ +void perf_event_update_userpage(struct perf_event *event) +{ + struct perf_event_mmap_page *userpg; + struct perf_buffer *buffer; + + rcu_read_lock(); + buffer = rcu_dereference(event->buffer); + if (!buffer) + goto unlock; + + userpg = buffer->user_page; + + /* + * Disable preemption so as to not let the corresponding user-space + * spin too long if we get preempted. + */ + preempt_disable(); + ++userpg->lock; + barrier(); + userpg->index = perf_event_index(event); + userpg->offset = perf_event_count(event); + if (event->state == PERF_EVENT_STATE_ACTIVE) + userpg->offset -= local64_read(&event->hw.prev_count); + + userpg->time_enabled = event->total_time_enabled + + atomic64_read(&event->child_total_time_enabled); + + userpg->time_running = event->total_time_running + + atomic64_read(&event->child_total_time_running); + + barrier(); + ++userpg->lock; + preempt_enable(); +unlock: + rcu_read_unlock(); +} + +static unsigned long perf_data_size(struct perf_buffer *buffer); + +static void +perf_buffer_init(struct perf_buffer *buffer, long watermark, int flags) +{ + long max_size = perf_data_size(buffer); + + if (watermark) + buffer->watermark = min(max_size, watermark); + + if (!buffer->watermark) + buffer->watermark = max_size / 2; + + if (flags & PERF_BUFFER_WRITABLE) + buffer->writable = 1; + + atomic_set(&buffer->refcount, 1); +} + +#ifndef CONFIG_PERF_USE_VMALLOC + +/* + * Back perf_mmap() with regular GFP_KERNEL-0 pages. + */ + +static struct page * +perf_mmap_to_page(struct perf_buffer *buffer, unsigned long pgoff) +{ + if (pgoff > buffer->nr_pages) + return NULL; + + if (pgoff == 0) + return virt_to_page(buffer->user_page); + + return virt_to_page(buffer->data_pages[pgoff - 1]); +} + +static void *perf_mmap_alloc_page(int cpu) +{ + struct page *page; + int node; + + node = (cpu == -1) ? cpu : cpu_to_node(cpu); + page = alloc_pages_node(node, GFP_KERNEL | __GFP_ZERO, 0); + if (!page) + return NULL; + + return page_address(page); +} + +static struct perf_buffer * +perf_buffer_alloc(int nr_pages, long watermark, int cpu, int flags) +{ + struct perf_buffer *buffer; + unsigned long size; + int i; + + size = sizeof(struct perf_buffer); + size += nr_pages * sizeof(void *); + + buffer = kzalloc(size, GFP_KERNEL); + if (!buffer) + goto fail; + + buffer->user_page = perf_mmap_alloc_page(cpu); + if (!buffer->user_page) + goto fail_user_page; + + for (i = 0; i < nr_pages; i++) { + buffer->data_pages[i] = perf_mmap_alloc_page(cpu); + if (!buffer->data_pages[i]) + goto fail_data_pages; + } + + buffer->nr_pages = nr_pages; + + perf_buffer_init(buffer, watermark, flags); + + return buffer; + +fail_data_pages: + for (i--; i >= 0; i--) + free_page((unsigned long)buffer->data_pages[i]); + + free_page((unsigned long)buffer->user_page); + +fail_user_page: + kfree(buffer); + +fail: + return NULL; +} + +static void perf_mmap_free_page(unsigned long addr) +{ + struct page *page = virt_to_page((void *)addr); + + page->mapping = NULL; + __free_page(page); +} + +static void perf_buffer_free(struct perf_buffer *buffer) +{ + int i; + + perf_mmap_free_page((unsigned long)buffer->user_page); + for (i = 0; i < buffer->nr_pages; i++) + perf_mmap_free_page((unsigned long)buffer->data_pages[i]); + kfree(buffer); +} + +static inline int page_order(struct perf_buffer *buffer) +{ + return 0; +} + +#else + +/* + * Back perf_mmap() with vmalloc memory. + * + * Required for architectures that have d-cache aliasing issues. + */ + +static inline int page_order(struct perf_buffer *buffer) +{ + return buffer->page_order; +} + +static struct page * +perf_mmap_to_page(struct perf_buffer *buffer, unsigned long pgoff) +{ + if (pgoff > (1UL << page_order(buffer))) + return NULL; + + return vmalloc_to_page((void *)buffer->user_page + pgoff * PAGE_SIZE); +} + +static void perf_mmap_unmark_page(void *addr) +{ + struct page *page = vmalloc_to_page(addr); + + page->mapping = NULL; +} + +static void perf_buffer_free_work(struct work_struct *work) +{ + struct perf_buffer *buffer; + void *base; + int i, nr; + + buffer = container_of(work, struct perf_buffer, work); + nr = 1 << page_order(buffer); + + base = buffer->user_page; + for (i = 0; i < nr + 1; i++) + perf_mmap_unmark_page(base + (i * PAGE_SIZE)); + + vfree(base); + kfree(buffer); +} + +static void perf_buffer_free(struct perf_buffer *buffer) +{ + schedule_work(&buffer->work); +} + +static struct perf_buffer * +perf_buffer_alloc(int nr_pages, long watermark, int cpu, int flags) +{ + struct perf_buffer *buffer; + unsigned long size; + void *all_buf; + + size = sizeof(struct perf_buffer); + size += sizeof(void *); + + buffer = kzalloc(size, GFP_KERNEL); + if (!buffer) + goto fail; + + INIT_WORK(&buffer->work, perf_buffer_free_work); + + all_buf = vmalloc_user((nr_pages + 1) * PAGE_SIZE); + if (!all_buf) + goto fail_all_buf; + + buffer->user_page = all_buf; + buffer->data_pages[0] = all_buf + PAGE_SIZE; + buffer->page_order = ilog2(nr_pages); + buffer->nr_pages = 1; + + perf_buffer_init(buffer, watermark, flags); + + return buffer; + +fail_all_buf: + kfree(buffer); + +fail: + return NULL; +} + +#endif + +static unsigned long perf_data_size(struct perf_buffer *buffer) +{ + return buffer->nr_pages << (PAGE_SHIFT + page_order(buffer)); +} + +static int perf_mmap_fault(struct vm_area_struct *vma, struct vm_fault *vmf) +{ + struct perf_event *event = vma->vm_file->private_data; + struct perf_buffer *buffer; + int ret = VM_FAULT_SIGBUS; + + if (vmf->flags & FAULT_FLAG_MKWRITE) { + if (vmf->pgoff == 0) + ret = 0; + return ret; + } + + rcu_read_lock(); + buffer = rcu_dereference(event->buffer); + if (!buffer) + goto unlock; + + if (vmf->pgoff && (vmf->flags & FAULT_FLAG_WRITE)) + goto unlock; + + vmf->page = perf_mmap_to_page(buffer, vmf->pgoff); + if (!vmf->page) + goto unlock; + + get_page(vmf->page); + vmf->page->mapping = vma->vm_file->f_mapping; + vmf->page->index = vmf->pgoff; + + ret = 0; +unlock: + rcu_read_unlock(); + + return ret; +} + +static void perf_buffer_free_rcu(struct rcu_head *rcu_head) +{ + struct perf_buffer *buffer; + + buffer = container_of(rcu_head, struct perf_buffer, rcu_head); + perf_buffer_free(buffer); +} + +static struct perf_buffer *perf_buffer_get(struct perf_event *event) +{ + struct perf_buffer *buffer; + + rcu_read_lock(); + buffer = rcu_dereference(event->buffer); + if (buffer) { + if (!atomic_inc_not_zero(&buffer->refcount)) + buffer = NULL; + } + rcu_read_unlock(); + + return buffer; +} + +static void perf_buffer_put(struct perf_buffer *buffer) +{ + if (!atomic_dec_and_test(&buffer->refcount)) + return; + + call_rcu(&buffer->rcu_head, perf_buffer_free_rcu); +} + +static void perf_mmap_open(struct vm_area_struct *vma) +{ + struct perf_event *event = vma->vm_file->private_data; + + atomic_inc(&event->mmap_count); +} + +static void perf_mmap_close(struct vm_area_struct *vma) +{ + struct perf_event *event = vma->vm_file->private_data; + + if (atomic_dec_and_mutex_lock(&event->mmap_count, &event->mmap_mutex)) { + unsigned long size = perf_data_size(event->buffer); + struct user_struct *user = event->mmap_user; + struct perf_buffer *buffer = event->buffer; + + atomic_long_sub((size >> PAGE_SHIFT) + 1, &user->locked_vm); + vma->vm_mm->locked_vm -= event->mmap_locked; + rcu_assign_pointer(event->buffer, NULL); + mutex_unlock(&event->mmap_mutex); + + perf_buffer_put(buffer); + free_uid(user); + } +} + +static const struct vm_operations_struct perf_mmap_vmops = { + .open = perf_mmap_open, + .close = perf_mmap_close, + .fault = perf_mmap_fault, + .page_mkwrite = perf_mmap_fault, +}; + +static int perf_mmap(struct file *file, struct vm_area_struct *vma) +{ + struct perf_event *event = file->private_data; + unsigned long user_locked, user_lock_limit; + struct user_struct *user = current_user(); + unsigned long locked, lock_limit; + struct perf_buffer *buffer; + unsigned long vma_size; + unsigned long nr_pages; + long user_extra, extra; + int ret = 0, flags = 0; + + /* + * Don't allow mmap() of inherited per-task counters. This would + * create a performance issue due to all children writing to the + * same buffer. + */ + if (event->cpu == -1 && event->attr.inherit) + return -EINVAL; + + if (!(vma->vm_flags & VM_SHARED)) + return -EINVAL; + + vma_size = vma->vm_end - vma->vm_start; + nr_pages = (vma_size / PAGE_SIZE) - 1; + + /* + * If we have buffer pages ensure they're a power-of-two number, so we + * can do bitmasks instead of modulo. + */ + if (nr_pages != 0 && !is_power_of_2(nr_pages)) + return -EINVAL; + + if (vma_size != PAGE_SIZE * (1 + nr_pages)) + return -EINVAL; + + if (vma->vm_pgoff != 0) + return -EINVAL; + + WARN_ON_ONCE(event->ctx->parent_ctx); + mutex_lock(&event->mmap_mutex); + if (event->buffer) { + if (event->buffer->nr_pages == nr_pages) + atomic_inc(&event->buffer->refcount); + else + ret = -EINVAL; + goto unlock; + } + + user_extra = nr_pages + 1; + user_lock_limit = sysctl_perf_event_mlock >> (PAGE_SHIFT - 10); + + /* + * Increase the limit linearly with more CPUs: + */ + user_lock_limit *= num_online_cpus(); + + user_locked = atomic_long_read(&user->locked_vm) + user_extra; + + extra = 0; + if (user_locked > user_lock_limit) + extra = user_locked - user_lock_limit; + + lock_limit = rlimit(RLIMIT_MEMLOCK); + lock_limit >>= PAGE_SHIFT; + locked = vma->vm_mm->locked_vm + extra; + + if ((locked > lock_limit) && perf_paranoid_tracepoint_raw() && + !capable(CAP_IPC_LOCK)) { + ret = -EPERM; + goto unlock; + } + + WARN_ON(event->buffer); + + if (vma->vm_flags & VM_WRITE) + flags |= PERF_BUFFER_WRITABLE; + + buffer = perf_buffer_alloc(nr_pages, event->attr.wakeup_watermark, + event->cpu, flags); + if (!buffer) { + ret = -ENOMEM; + goto unlock; + } + rcu_assign_pointer(event->buffer, buffer); + + atomic_long_add(user_extra, &user->locked_vm); + event->mmap_locked = extra; + event->mmap_user = get_current_user(); + vma->vm_mm->locked_vm += event->mmap_locked; + +unlock: + if (!ret) + atomic_inc(&event->mmap_count); + mutex_unlock(&event->mmap_mutex); + + vma->vm_flags |= VM_RESERVED; + vma->vm_ops = &perf_mmap_vmops; + + return ret; +} + +static int perf_fasync(int fd, struct file *filp, int on) +{ + struct inode *inode = filp->f_path.dentry->d_inode; + struct perf_event *event = filp->private_data; + int retval; + + mutex_lock(&inode->i_mutex); + retval = fasync_helper(fd, filp, on, &event->fasync); + mutex_unlock(&inode->i_mutex); + + if (retval < 0) + return retval; + + return 0; +} + +static const struct file_operations perf_fops = { + .llseek = no_llseek, + .release = perf_release, + .read = perf_read, + .poll = perf_poll, + .unlocked_ioctl = perf_ioctl, + .compat_ioctl = perf_ioctl, + .mmap = perf_mmap, + .fasync = perf_fasync, +}; + +/* + * Perf event wakeup + * + * If there's data, ensure we set the poll() state and publish everything + * to user-space before waking everybody up. + */ + +void perf_event_wakeup(struct perf_event *event) +{ + wake_up_all(&event->waitq); + + if (event->pending_kill) { + kill_fasync(&event->fasync, SIGIO, event->pending_kill); + event->pending_kill = 0; + } +} + +static void perf_pending_event(struct irq_work *entry) +{ + struct perf_event *event = container_of(entry, + struct perf_event, pending); + + if (event->pending_disable) { + event->pending_disable = 0; + __perf_event_disable(event); + } + + if (event->pending_wakeup) { + event->pending_wakeup = 0; + perf_event_wakeup(event); + } +} + +/* + * We assume there is only KVM supporting the callbacks. + * Later on, we might change it to a list if there is + * another virtualization implementation supporting the callbacks. + */ +struct perf_guest_info_callbacks *perf_guest_cbs; + +int perf_register_guest_info_callbacks(struct perf_guest_info_callbacks *cbs) +{ + perf_guest_cbs = cbs; + return 0; +} +EXPORT_SYMBOL_GPL(perf_register_guest_info_callbacks); + +int perf_unregister_guest_info_callbacks(struct perf_guest_info_callbacks *cbs) +{ + perf_guest_cbs = NULL; + return 0; +} +EXPORT_SYMBOL_GPL(perf_unregister_guest_info_callbacks); + +/* + * Output + */ +static bool perf_output_space(struct perf_buffer *buffer, unsigned long tail, + unsigned long offset, unsigned long head) +{ + unsigned long mask; + + if (!buffer->writable) + return true; + + mask = perf_data_size(buffer) - 1; + + offset = (offset - tail) & mask; + head = (head - tail) & mask; + + if ((int)(head - offset) < 0) + return false; + + return true; +} + +static void perf_output_wakeup(struct perf_output_handle *handle) +{ + atomic_set(&handle->buffer->poll, POLL_IN); + + if (handle->nmi) { + handle->event->pending_wakeup = 1; + irq_work_queue(&handle->event->pending); + } else + perf_event_wakeup(handle->event); +} + +/* + * We need to ensure a later event_id doesn't publish a head when a former + * event isn't done writing. However since we need to deal with NMIs we + * cannot fully serialize things. + * + * We only publish the head (and generate a wakeup) when the outer-most + * event completes. + */ +static void perf_output_get_handle(struct perf_output_handle *handle) +{ + struct perf_buffer *buffer = handle->buffer; + + preempt_disable(); + local_inc(&buffer->nest); + handle->wakeup = local_read(&buffer->wakeup); +} + +static void perf_output_put_handle(struct perf_output_handle *handle) +{ + struct perf_buffer *buffer = handle->buffer; + unsigned long head; + +again: + head = local_read(&buffer->head); + + /* + * IRQ/NMI can happen here, which means we can miss a head update. + */ + + if (!local_dec_and_test(&buffer->nest)) + goto out; + + /* + * Publish the known good head. Rely on the full barrier implied + * by atomic_dec_and_test() order the buffer->head read and this + * write. + */ + buffer->user_page->data_head = head; + + /* + * Now check if we missed an update, rely on the (compiler) + * barrier in atomic_dec_and_test() to re-read buffer->head. + */ + if (unlikely(head != local_read(&buffer->head))) { + local_inc(&buffer->nest); + goto again; + } + + if (handle->wakeup != local_read(&buffer->wakeup)) + perf_output_wakeup(handle); + +out: + preempt_enable(); +} + +__always_inline void perf_output_copy(struct perf_output_handle *handle, + const void *buf, unsigned int len) +{ + do { + unsigned long size = min_t(unsigned long, handle->size, len); + + memcpy(handle->addr, buf, size); + + len -= size; + handle->addr += size; + buf += size; + handle->size -= size; + if (!handle->size) { + struct perf_buffer *buffer = handle->buffer; + + handle->page++; + handle->page &= buffer->nr_pages - 1; + handle->addr = buffer->data_pages[handle->page]; + handle->size = PAGE_SIZE << page_order(buffer); + } + } while (len); +} + +static void __perf_event_header__init_id(struct perf_event_header *header, + struct perf_sample_data *data, + struct perf_event *event) +{ + u64 sample_type = event->attr.sample_type; + + data->type = sample_type; + header->size += event->id_header_size; + + if (sample_type & PERF_SAMPLE_TID) { + /* namespace issues */ + data->tid_entry.pid = perf_event_pid(event, current); + data->tid_entry.tid = perf_event_tid(event, current); + } + + if (sample_type & PERF_SAMPLE_TIME) + data->time = perf_clock(); + + if (sample_type & PERF_SAMPLE_ID) + data->id = primary_event_id(event); + + if (sample_type & PERF_SAMPLE_STREAM_ID) + data->stream_id = event->id; + + if (sample_type & PERF_SAMPLE_CPU) { + data->cpu_entry.cpu = raw_smp_processor_id(); + data->cpu_entry.reserved = 0; + } +} + +static void perf_event_header__init_id(struct perf_event_header *header, + struct perf_sample_data *data, + struct perf_event *event) +{ + if (event->attr.sample_id_all) + __perf_event_header__init_id(header, data, event); +} + +static void __perf_event__output_id_sample(struct perf_output_handle *handle, + struct perf_sample_data *data) +{ + u64 sample_type = data->type; + + if (sample_type & PERF_SAMPLE_TID) + perf_output_put(handle, data->tid_entry); + + if (sample_type & PERF_SAMPLE_TIME) + perf_output_put(handle, data->time); + + if (sample_type & PERF_SAMPLE_ID) + perf_output_put(handle, data->id); + + if (sample_type & PERF_SAMPLE_STREAM_ID) + perf_output_put(handle, data->stream_id); + + if (sample_type & PERF_SAMPLE_CPU) + perf_output_put(handle, data->cpu_entry); +} + +static void perf_event__output_id_sample(struct perf_event *event, + struct perf_output_handle *handle, + struct perf_sample_data *sample) +{ + if (event->attr.sample_id_all) + __perf_event__output_id_sample(handle, sample); +} + +int perf_output_begin(struct perf_output_handle *handle, + struct perf_event *event, unsigned int size, + int nmi, int sample) +{ + struct perf_buffer *buffer; + unsigned long tail, offset, head; + int have_lost; + struct perf_sample_data sample_data; + struct { + struct perf_event_header header; + u64 id; + u64 lost; + } lost_event; + + rcu_read_lock(); + /* + * For inherited events we send all the output towards the parent. + */ + if (event->parent) + event = event->parent; + + buffer = rcu_dereference(event->buffer); + if (!buffer) + goto out; + + handle->buffer = buffer; + handle->event = event; + handle->nmi = nmi; + handle->sample = sample; + + if (!buffer->nr_pages) + goto out; + + have_lost = local_read(&buffer->lost); + if (have_lost) { + lost_event.header.size = sizeof(lost_event); + perf_event_header__init_id(&lost_event.header, &sample_data, + event); + size += lost_event.header.size; + } + + perf_output_get_handle(handle); + + do { + /* + * Userspace could choose to issue a mb() before updating the + * tail pointer. So that all reads will be completed before the + * write is issued. + */ + tail = ACCESS_ONCE(buffer->user_page->data_tail); + smp_rmb(); + offset = head = local_read(&buffer->head); + head += size; + if (unlikely(!perf_output_space(buffer, tail, offset, head))) + goto fail; + } while (local_cmpxchg(&buffer->head, offset, head) != offset); + + if (head - local_read(&buffer->wakeup) > buffer->watermark) + local_add(buffer->watermark, &buffer->wakeup); + + handle->page = offset >> (PAGE_SHIFT + page_order(buffer)); + handle->page &= buffer->nr_pages - 1; + handle->size = offset & ((PAGE_SIZE << page_order(buffer)) - 1); + handle->addr = buffer->data_pages[handle->page]; + handle->addr += handle->size; + handle->size = (PAGE_SIZE << page_order(buffer)) - handle->size; + + if (have_lost) { + lost_event.header.type = PERF_RECORD_LOST; + lost_event.header.misc = 0; + lost_event.id = event->id; + lost_event.lost = local_xchg(&buffer->lost, 0); + + perf_output_put(handle, lost_event); + perf_event__output_id_sample(event, handle, &sample_data); + } + + return 0; + +fail: + local_inc(&buffer->lost); + perf_output_put_handle(handle); +out: + rcu_read_unlock(); + + return -ENOSPC; +} + +void perf_output_end(struct perf_output_handle *handle) +{ + struct perf_event *event = handle->event; + struct perf_buffer *buffer = handle->buffer; + + int wakeup_events = event->attr.wakeup_events; + + if (handle->sample && wakeup_events) { + int events = local_inc_return(&buffer->events); + if (events >= wakeup_events) { + local_sub(wakeup_events, &buffer->events); + local_inc(&buffer->wakeup); + } + } + + perf_output_put_handle(handle); + rcu_read_unlock(); +} + +static void perf_output_read_one(struct perf_output_handle *handle, + struct perf_event *event, + u64 enabled, u64 running) +{ + u64 read_format = event->attr.read_format; + u64 values[4]; + int n = 0; + + values[n++] = perf_event_count(event); + if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED) { + values[n++] = enabled + + atomic64_read(&event->child_total_time_enabled); + } + if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING) { + values[n++] = running + + atomic64_read(&event->child_total_time_running); + } + if (read_format & PERF_FORMAT_ID) + values[n++] = primary_event_id(event); + + perf_output_copy(handle, values, n * sizeof(u64)); +} + +/* + * XXX PERF_FORMAT_GROUP vs inherited events seems difficult. + */ +static void perf_output_read_group(struct perf_output_handle *handle, + struct perf_event *event, + u64 enabled, u64 running) +{ + struct perf_event *leader = event->group_leader, *sub; + u64 read_format = event->attr.read_format; + u64 values[5]; + int n = 0; + + values[n++] = 1 + leader->nr_siblings; + + if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED) + values[n++] = enabled; + + if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING) + values[n++] = running; + + if (leader != event) + leader->pmu->read(leader); + + values[n++] = perf_event_count(leader); + if (read_format & PERF_FORMAT_ID) + values[n++] = primary_event_id(leader); + + perf_output_copy(handle, values, n * sizeof(u64)); + + list_for_each_entry(sub, &leader->sibling_list, group_entry) { + n = 0; + + if (sub != event) + sub->pmu->read(sub); + + values[n++] = perf_event_count(sub); + if (read_format & PERF_FORMAT_ID) + values[n++] = primary_event_id(sub); + + perf_output_copy(handle, values, n * sizeof(u64)); + } +} + +#define PERF_FORMAT_TOTAL_TIMES (PERF_FORMAT_TOTAL_TIME_ENABLED|\ + PERF_FORMAT_TOTAL_TIME_RUNNING) + +static void perf_output_read(struct perf_output_handle *handle, + struct perf_event *event) +{ + u64 enabled = 0, running = 0, now, ctx_time; + u64 read_format = event->attr.read_format; + + /* + * compute total_time_enabled, total_time_running + * based on snapshot values taken when the event + * was last scheduled in. + * + * we cannot simply called update_context_time() + * because of locking issue as we are called in + * NMI context + */ + if (read_format & PERF_FORMAT_TOTAL_TIMES) { + now = perf_clock(); + ctx_time = event->shadow_ctx_time + now; + enabled = ctx_time - event->tstamp_enabled; + running = ctx_time - event->tstamp_running; + } + + if (event->attr.read_format & PERF_FORMAT_GROUP) + perf_output_read_group(handle, event, enabled, running); + else + perf_output_read_one(handle, event, enabled, running); +} + +void perf_output_sample(struct perf_output_handle *handle, + struct perf_event_header *header, + struct perf_sample_data *data, + struct perf_event *event) +{ + u64 sample_type = data->type; + + perf_output_put(handle, *header); + + if (sample_type & PERF_SAMPLE_IP) + perf_output_put(handle, data->ip); + + if (sample_type & PERF_SAMPLE_TID) + perf_output_put(handle, data->tid_entry); + + if (sample_type & PERF_SAMPLE_TIME) + perf_output_put(handle, data->time); + + if (sample_type & PERF_SAMPLE_ADDR) + perf_output_put(handle, data->addr); + + if (sample_type & PERF_SAMPLE_ID) + perf_output_put(handle, data->id); + + if (sample_type & PERF_SAMPLE_STREAM_ID) + perf_output_put(handle, data->stream_id); + + if (sample_type & PERF_SAMPLE_CPU) + perf_output_put(handle, data->cpu_entry); + + if (sample_type & PERF_SAMPLE_PERIOD) + perf_output_put(handle, data->period); + + if (sample_type & PERF_SAMPLE_READ) + perf_output_read(handle, event); + + if (sample_type & PERF_SAMPLE_CALLCHAIN) { + if (data->callchain) { + int size = 1; + + if (data->callchain) + size += data->callchain->nr; + + size *= sizeof(u64); + + perf_output_copy(handle, data->callchain, size); + } else { + u64 nr = 0; + perf_output_put(handle, nr); + } + } + + if (sample_type & PERF_SAMPLE_RAW) { + if (data->raw) { + perf_output_put(handle, data->raw->size); + perf_output_copy(handle, data->raw->data, + data->raw->size); + } else { + struct { + u32 size; + u32 data; + } raw = { + .size = sizeof(u32), + .data = 0, + }; + perf_output_put(handle, raw); + } + } +} + +void perf_prepare_sample(struct perf_event_header *header, + struct perf_sample_data *data, + struct perf_event *event, + struct pt_regs *regs) +{ + u64 sample_type = event->attr.sample_type; + + header->type = PERF_RECORD_SAMPLE; + header->size = sizeof(*header) + event->header_size; + + header->misc = 0; + header->misc |= perf_misc_flags(regs); + + __perf_event_header__init_id(header, data, event); + + if (sample_type & PERF_SAMPLE_IP) + data->ip = perf_instruction_pointer(regs); + + if (sample_type & PERF_SAMPLE_CALLCHAIN) { + int size = 1; + + data->callchain = perf_callchain(regs); + + if (data->callchain) + size += data->callchain->nr; + + header->size += size * sizeof(u64); + } + + if (sample_type & PERF_SAMPLE_RAW) { + int size = sizeof(u32); + + if (data->raw) + size += data->raw->size; + else + size += sizeof(u32); + + WARN_ON_ONCE(size & (sizeof(u64)-1)); + header->size += size; + } +} + +static void perf_event_output(struct perf_event *event, int nmi, + struct perf_sample_data *data, + struct pt_regs *regs) +{ + struct perf_output_handle handle; + struct perf_event_header header; + + /* protect the callchain buffers */ + rcu_read_lock(); + + perf_prepare_sample(&header, data, event, regs); + + if (perf_output_begin(&handle, event, header.size, nmi, 1)) + goto exit; + + perf_output_sample(&handle, &header, data, event); + + perf_output_end(&handle); + +exit: + rcu_read_unlock(); +} + +/* + * read event_id + */ + +struct perf_read_event { + struct perf_event_header header; + + u32 pid; + u32 tid; +}; + +static void +perf_event_read_event(struct perf_event *event, + struct task_struct *task) +{ + struct perf_output_handle handle; + struct perf_sample_data sample; + struct perf_read_event read_event = { + .header = { + .type = PERF_RECORD_READ, + .misc = 0, + .size = sizeof(read_event) + event->read_size, + }, + .pid = perf_event_pid(event, task), + .tid = perf_event_tid(event, task), + }; + int ret; + + perf_event_header__init_id(&read_event.header, &sample, event); + ret = perf_output_begin(&handle, event, read_event.header.size, 0, 0); + if (ret) + return; + + perf_output_put(&handle, read_event); + perf_output_read(&handle, event); + perf_event__output_id_sample(event, &handle, &sample); + + perf_output_end(&handle); +} + +/* + * task tracking -- fork/exit + * + * enabled by: attr.comm | attr.mmap | attr.mmap_data | attr.task + */ + +struct perf_task_event { + struct task_struct *task; + struct perf_event_context *task_ctx; + + struct { + struct perf_event_header header; + + u32 pid; + u32 ppid; + u32 tid; + u32 ptid; + u64 time; + } event_id; +}; + +static void perf_event_task_output(struct perf_event *event, + struct perf_task_event *task_event) +{ + struct perf_output_handle handle; + struct perf_sample_data sample; + struct task_struct *task = task_event->task; + int ret, size = task_event->event_id.header.size; + + perf_event_header__init_id(&task_event->event_id.header, &sample, event); + + ret = perf_output_begin(&handle, event, + task_event->event_id.header.size, 0, 0); + if (ret) + goto out; + + task_event->event_id.pid = perf_event_pid(event, task); + task_event->event_id.ppid = perf_event_pid(event, current); + + task_event->event_id.tid = perf_event_tid(event, task); + task_event->event_id.ptid = perf_event_tid(event, current); + + perf_output_put(&handle, task_event->event_id); + + perf_event__output_id_sample(event, &handle, &sample); + + perf_output_end(&handle); +out: + task_event->event_id.header.size = size; +} + +static int perf_event_task_match(struct perf_event *event) +{ + if (event->state < PERF_EVENT_STATE_INACTIVE) + return 0; + + if (!event_filter_match(event)) + return 0; + + if (event->attr.comm || event->attr.mmap || + event->attr.mmap_data || event->attr.task) + return 1; + + return 0; +} + +static void perf_event_task_ctx(struct perf_event_context *ctx, + struct perf_task_event *task_event) +{ + struct perf_event *event; + + list_for_each_entry_rcu(event, &ctx->event_list, event_entry) { + if (perf_event_task_match(event)) + perf_event_task_output(event, task_event); + } +} + +static void perf_event_task_event(struct perf_task_event *task_event) +{ + struct perf_cpu_context *cpuctx; + struct perf_event_context *ctx; + struct pmu *pmu; + int ctxn; + + rcu_read_lock(); + list_for_each_entry_rcu(pmu, &pmus, entry) { + cpuctx = get_cpu_ptr(pmu->pmu_cpu_context); + if (cpuctx->active_pmu != pmu) + goto next; + perf_event_task_ctx(&cpuctx->ctx, task_event); + + ctx = task_event->task_ctx; + if (!ctx) { + ctxn = pmu->task_ctx_nr; + if (ctxn < 0) + goto next; + ctx = rcu_dereference(current->perf_event_ctxp[ctxn]); + } + if (ctx) + perf_event_task_ctx(ctx, task_event); +next: + put_cpu_ptr(pmu->pmu_cpu_context); + } + rcu_read_unlock(); +} + +static void perf_event_task(struct task_struct *task, + struct perf_event_context *task_ctx, + int new) +{ + struct perf_task_event task_event; + + if (!atomic_read(&nr_comm_events) && + !atomic_read(&nr_mmap_events) && + !atomic_read(&nr_task_events)) + return; + + task_event = (struct perf_task_event){ + .task = task, + .task_ctx = task_ctx, + .event_id = { + .header = { + .type = new ? PERF_RECORD_FORK : PERF_RECORD_EXIT, + .misc = 0, + .size = sizeof(task_event.event_id), + }, + /* .pid */ + /* .ppid */ + /* .tid */ + /* .ptid */ + .time = perf_clock(), + }, + }; + + perf_event_task_event(&task_event); +} + +void perf_event_fork(struct task_struct *task) +{ + perf_event_task(task, NULL, 1); +} + +/* + * comm tracking + */ + +struct perf_comm_event { + struct task_struct *task; + char *comm; + int comm_size; + + struct { + struct perf_event_header header; + + u32 pid; + u32 tid; + } event_id; +}; + +static void perf_event_comm_output(struct perf_event *event, + struct perf_comm_event *comm_event) +{ + struct perf_output_handle handle; + struct perf_sample_data sample; + int size = comm_event->event_id.header.size; + int ret; + + perf_event_header__init_id(&comm_event->event_id.header, &sample, event); + ret = perf_output_begin(&handle, event, + comm_event->event_id.header.size, 0, 0); + + if (ret) + goto out; + + comm_event->event_id.pid = perf_event_pid(event, comm_event->task); + comm_event->event_id.tid = perf_event_tid(event, comm_event->task); + + perf_output_put(&handle, comm_event->event_id); + perf_output_copy(&handle, comm_event->comm, + comm_event->comm_size); + + perf_event__output_id_sample(event, &handle, &sample); + + perf_output_end(&handle); +out: + comm_event->event_id.header.size = size; +} + +static int perf_event_comm_match(struct perf_event *event) +{ + if (event->state < PERF_EVENT_STATE_INACTIVE) + return 0; + + if (!event_filter_match(event)) + return 0; + + if (event->attr.comm) + return 1; + + return 0; +} + +static void perf_event_comm_ctx(struct perf_event_context *ctx, + struct perf_comm_event *comm_event) +{ + struct perf_event *event; + + list_for_each_entry_rcu(event, &ctx->event_list, event_entry) { + if (perf_event_comm_match(event)) + perf_event_comm_output(event, comm_event); + } +} + +static void perf_event_comm_event(struct perf_comm_event *comm_event) +{ + struct perf_cpu_context *cpuctx; + struct perf_event_context *ctx; + char comm[TASK_COMM_LEN]; + unsigned int size; + struct pmu *pmu; + int ctxn; + + memset(comm, 0, sizeof(comm)); + strlcpy(comm, comm_event->task->comm, sizeof(comm)); + size = ALIGN(strlen(comm)+1, sizeof(u64)); + + comm_event->comm = comm; + comm_event->comm_size = size; + + comm_event->event_id.header.size = sizeof(comm_event->event_id) + size; + rcu_read_lock(); + list_for_each_entry_rcu(pmu, &pmus, entry) { + cpuctx = get_cpu_ptr(pmu->pmu_cpu_context); + if (cpuctx->active_pmu != pmu) + goto next; + perf_event_comm_ctx(&cpuctx->ctx, comm_event); + + ctxn = pmu->task_ctx_nr; + if (ctxn < 0) + goto next; + + ctx = rcu_dereference(current->perf_event_ctxp[ctxn]); + if (ctx) + perf_event_comm_ctx(ctx, comm_event); +next: + put_cpu_ptr(pmu->pmu_cpu_context); + } + rcu_read_unlock(); +} + +void perf_event_comm(struct task_struct *task) +{ + struct perf_comm_event comm_event; + struct perf_event_context *ctx; + int ctxn; + + for_each_task_context_nr(ctxn) { + ctx = task->perf_event_ctxp[ctxn]; + if (!ctx) + continue; + + perf_event_enable_on_exec(ctx); + } + + if (!atomic_read(&nr_comm_events)) + return; + + comm_event = (struct perf_comm_event){ + .task = task, + /* .comm */ + /* .comm_size */ + .event_id = { + .header = { + .type = PERF_RECORD_COMM, + .misc = 0, + /* .size */ + }, + /* .pid */ + /* .tid */ + }, + }; + + perf_event_comm_event(&comm_event); +} + +/* + * mmap tracking + */ + +struct perf_mmap_event { + struct vm_area_struct *vma; + + const char *file_name; + int file_size; + + struct { + struct perf_event_header header; + + u32 pid; + u32 tid; + u64 start; + u64 len; + u64 pgoff; + } event_id; +}; + +static void perf_event_mmap_output(struct perf_event *event, + struct perf_mmap_event *mmap_event) +{ + struct perf_output_handle handle; + struct perf_sample_data sample; + int size = mmap_event->event_id.header.size; + int ret; + + perf_event_header__init_id(&mmap_event->event_id.header, &sample, event); + ret = perf_output_begin(&handle, event, + mmap_event->event_id.header.size, 0, 0); + if (ret) + goto out; + + mmap_event->event_id.pid = perf_event_pid(event, current); + mmap_event->event_id.tid = perf_event_tid(event, current); + + perf_output_put(&handle, mmap_event->event_id); + perf_output_copy(&handle, mmap_event->file_name, + mmap_event->file_size); + + perf_event__output_id_sample(event, &handle, &sample); + + perf_output_end(&handle); +out: + mmap_event->event_id.header.size = size; +} + +static int perf_event_mmap_match(struct perf_event *event, + struct perf_mmap_event *mmap_event, + int executable) +{ + if (event->state < PERF_EVENT_STATE_INACTIVE) + return 0; + + if (!event_filter_match(event)) + return 0; + + if ((!executable && event->attr.mmap_data) || + (executable && event->attr.mmap)) + return 1; + + return 0; +} + +static void perf_event_mmap_ctx(struct perf_event_context *ctx, + struct perf_mmap_event *mmap_event, + int executable) +{ + struct perf_event *event; + + list_for_each_entry_rcu(event, &ctx->event_list, event_entry) { + if (perf_event_mmap_match(event, mmap_event, executable)) + perf_event_mmap_output(event, mmap_event); + } +} + +static void perf_event_mmap_event(struct perf_mmap_event *mmap_event) +{ + struct perf_cpu_context *cpuctx; + struct perf_event_context *ctx; + struct vm_area_struct *vma = mmap_event->vma; + struct file *file = vma->vm_file; + unsigned int size; + char tmp[16]; + char *buf = NULL; + const char *name; + struct pmu *pmu; + int ctxn; + + memset(tmp, 0, sizeof(tmp)); + + if (file) { + /* + * d_path works from the end of the buffer backwards, so we + * need to add enough zero bytes after the string to handle + * the 64bit alignment we do later. + */ + buf = kzalloc(PATH_MAX + sizeof(u64), GFP_KERNEL); + if (!buf) { + name = strncpy(tmp, "//enomem", sizeof(tmp)); + goto got_name; + } + name = d_path(&file->f_path, buf, PATH_MAX); + if (IS_ERR(name)) { + name = strncpy(tmp, "//toolong", sizeof(tmp)); + goto got_name; + } + } else { + if (arch_vma_name(mmap_event->vma)) { + name = strncpy(tmp, arch_vma_name(mmap_event->vma), + sizeof(tmp)); + goto got_name; + } + + if (!vma->vm_mm) { + name = strncpy(tmp, "[vdso]", sizeof(tmp)); + goto got_name; + } else if (vma->vm_start <= vma->vm_mm->start_brk && + vma->vm_end >= vma->vm_mm->brk) { + name = strncpy(tmp, "[heap]", sizeof(tmp)); + goto got_name; + } else if (vma->vm_start <= vma->vm_mm->start_stack && + vma->vm_end >= vma->vm_mm->start_stack) { + name = strncpy(tmp, "[stack]", sizeof(tmp)); + goto got_name; + } + + name = strncpy(tmp, "//anon", sizeof(tmp)); + goto got_name; + } + +got_name: + size = ALIGN(strlen(name)+1, sizeof(u64)); + + mmap_event->file_name = name; + mmap_event->file_size = size; + + mmap_event->event_id.header.size = sizeof(mmap_event->event_id) + size; + + rcu_read_lock(); + list_for_each_entry_rcu(pmu, &pmus, entry) { + cpuctx = get_cpu_ptr(pmu->pmu_cpu_context); + if (cpuctx->active_pmu != pmu) + goto next; + perf_event_mmap_ctx(&cpuctx->ctx, mmap_event, + vma->vm_flags & VM_EXEC); + + ctxn = pmu->task_ctx_nr; + if (ctxn < 0) + goto next; + + ctx = rcu_dereference(current->perf_event_ctxp[ctxn]); + if (ctx) { + perf_event_mmap_ctx(ctx, mmap_event, + vma->vm_flags & VM_EXEC); + } +next: + put_cpu_ptr(pmu->pmu_cpu_context); + } + rcu_read_unlock(); + + kfree(buf); +} + +void perf_event_mmap(struct vm_area_struct *vma) +{ + struct perf_mmap_event mmap_event; + + if (!atomic_read(&nr_mmap_events)) + return; + + mmap_event = (struct perf_mmap_event){ + .vma = vma, + /* .file_name */ + /* .file_size */ + .event_id = { + .header = { + .type = PERF_RECORD_MMAP, + .misc = PERF_RECORD_MISC_USER, + /* .size */ + }, + /* .pid */ + /* .tid */ + .start = vma->vm_start, + .len = vma->vm_end - vma->vm_start, + .pgoff = (u64)vma->vm_pgoff << PAGE_SHIFT, + }, + }; + + perf_event_mmap_event(&mmap_event); +} + +/* + * IRQ throttle logging + */ + +static void perf_log_throttle(struct perf_event *event, int enable) +{ + struct perf_output_handle handle; + struct perf_sample_data sample; + int ret; + + struct { + struct perf_event_header header; + u64 time; + u64 id; + u64 stream_id; + } throttle_event = { + .header = { + .type = PERF_RECORD_THROTTLE, + .misc = 0, + .size = sizeof(throttle_event), + }, + .time = perf_clock(), + .id = primary_event_id(event), + .stream_id = event->id, + }; + + if (enable) + throttle_event.header.type = PERF_RECORD_UNTHROTTLE; + + perf_event_header__init_id(&throttle_event.header, &sample, event); + + ret = perf_output_begin(&handle, event, + throttle_event.header.size, 1, 0); + if (ret) + return; + + perf_output_put(&handle, throttle_event); + perf_event__output_id_sample(event, &handle, &sample); + perf_output_end(&handle); +} + +/* + * Generic event overflow handling, sampling. + */ + +static int __perf_event_overflow(struct perf_event *event, int nmi, + int throttle, struct perf_sample_data *data, + struct pt_regs *regs) +{ + int events = atomic_read(&event->event_limit); + struct hw_perf_event *hwc = &event->hw; + int ret = 0; + + /* + * Non-sampling counters might still use the PMI to fold short + * hardware counters, ignore those. + */ + if (unlikely(!is_sampling_event(event))) + return 0; + + if (unlikely(hwc->interrupts >= max_samples_per_tick)) { + if (throttle) { + hwc->interrupts = MAX_INTERRUPTS; + perf_log_throttle(event, 0); + ret = 1; + } + } else + hwc->interrupts++; + + if (event->attr.freq) { + u64 now = perf_clock(); + s64 delta = now - hwc->freq_time_stamp; + + hwc->freq_time_stamp = now; + + if (delta > 0 && delta < 2*TICK_NSEC) + perf_adjust_period(event, delta, hwc->last_period); + } + + /* + * XXX event_limit might not quite work as expected on inherited + * events + */ + + event->pending_kill = POLL_IN; + if (events && atomic_dec_and_test(&event->event_limit)) { + ret = 1; + event->pending_kill = POLL_HUP; + if (nmi) { + event->pending_disable = 1; + irq_work_queue(&event->pending); + } else + perf_event_disable(event); + } + + if (event->overflow_handler) + event->overflow_handler(event, nmi, data, regs); + else + perf_event_output(event, nmi, data, regs); + + return ret; +} + +int perf_event_overflow(struct perf_event *event, int nmi, + struct perf_sample_data *data, + struct pt_regs *regs) +{ + return __perf_event_overflow(event, nmi, 1, data, regs); +} + +/* + * Generic software event infrastructure + */ + +struct swevent_htable { + struct swevent_hlist *swevent_hlist; + struct mutex hlist_mutex; + int hlist_refcount; + + /* Recursion avoidance in each contexts */ + int recursion[PERF_NR_CONTEXTS]; +}; + +static DEFINE_PER_CPU(struct swevent_htable, swevent_htable); + +/* + * We directly increment event->count and keep a second value in + * event->hw.period_left to count intervals. This period event + * is kept in the range [-sample_period, 0] so that we can use the + * sign as trigger. + */ + +static u64 perf_swevent_set_period(struct perf_event *event) +{ + struct hw_perf_event *hwc = &event->hw; + u64 period = hwc->last_period; + u64 nr, offset; + s64 old, val; + + hwc->last_period = hwc->sample_period; + +again: + old = val = local64_read(&hwc->period_left); + if (val < 0) + return 0; + + nr = div64_u64(period + val, period); + offset = nr * period; + val -= offset; + if (local64_cmpxchg(&hwc->period_left, old, val) != old) + goto again; + + return nr; +} + +static void perf_swevent_overflow(struct perf_event *event, u64 overflow, + int nmi, struct perf_sample_data *data, + struct pt_regs *regs) +{ + struct hw_perf_event *hwc = &event->hw; + int throttle = 0; + + data->period = event->hw.last_period; + if (!overflow) + overflow = perf_swevent_set_period(event); + + if (hwc->interrupts == MAX_INTERRUPTS) + return; + + for (; overflow; overflow--) { + if (__perf_event_overflow(event, nmi, throttle, + data, regs)) { + /* + * We inhibit the overflow from happening when + * hwc->interrupts == MAX_INTERRUPTS. + */ + break; + } + throttle = 1; + } +} + +static void perf_swevent_event(struct perf_event *event, u64 nr, + int nmi, struct perf_sample_data *data, + struct pt_regs *regs) +{ + struct hw_perf_event *hwc = &event->hw; + + local64_add(nr, &event->count); + + if (!regs) + return; + + if (!is_sampling_event(event)) + return; + + if (nr == 1 && hwc->sample_period == 1 && !event->attr.freq) + return perf_swevent_overflow(event, 1, nmi, data, regs); + + if (local64_add_negative(nr, &hwc->period_left)) + return; + + perf_swevent_overflow(event, 0, nmi, data, regs); +} + +static int perf_exclude_event(struct perf_event *event, + struct pt_regs *regs) +{ + if (event->hw.state & PERF_HES_STOPPED) + return 1; + + if (regs) { + if (event->attr.exclude_user && user_mode(regs)) + return 1; + + if (event->attr.exclude_kernel && !user_mode(regs)) + return 1; + } + + return 0; +} + +static int perf_swevent_match(struct perf_event *event, + enum perf_type_id type, + u32 event_id, + struct perf_sample_data *data, + struct pt_regs *regs) +{ + if (event->attr.type != type) + return 0; + + if (event->attr.config != event_id) + return 0; + + if (perf_exclude_event(event, regs)) + return 0; + + return 1; +} + +static inline u64 swevent_hash(u64 type, u32 event_id) +{ + u64 val = event_id | (type << 32); + + return hash_64(val, SWEVENT_HLIST_BITS); +} + +static inline struct hlist_head * +__find_swevent_head(struct swevent_hlist *hlist, u64 type, u32 event_id) +{ + u64 hash = swevent_hash(type, event_id); + + return &hlist->heads[hash]; +} + +/* For the read side: events when they trigger */ +static inline struct hlist_head * +find_swevent_head_rcu(struct swevent_htable *swhash, u64 type, u32 event_id) +{ + struct swevent_hlist *hlist; + + hlist = rcu_dereference(swhash->swevent_hlist); + if (!hlist) + return NULL; + + return __find_swevent_head(hlist, type, event_id); +} + +/* For the event head insertion and removal in the hlist */ +static inline struct hlist_head * +find_swevent_head(struct swevent_htable *swhash, struct perf_event *event) +{ + struct swevent_hlist *hlist; + u32 event_id = event->attr.config; + u64 type = event->attr.type; + + /* + * Event scheduling is always serialized against hlist allocation + * and release. Which makes the protected version suitable here. + * The context lock guarantees that. + */ + hlist = rcu_dereference_protected(swhash->swevent_hlist, + lockdep_is_held(&event->ctx->lock)); + if (!hlist) + return NULL; + + return __find_swevent_head(hlist, type, event_id); +} + +static void do_perf_sw_event(enum perf_type_id type, u32 event_id, + u64 nr, int nmi, + struct perf_sample_data *data, + struct pt_regs *regs) +{ + struct swevent_htable *swhash = &__get_cpu_var(swevent_htable); + struct perf_event *event; + struct hlist_node *node; + struct hlist_head *head; + + rcu_read_lock(); + head = find_swevent_head_rcu(swhash, type, event_id); + if (!head) + goto end; + + hlist_for_each_entry_rcu(event, node, head, hlist_entry) { + if (perf_swevent_match(event, type, event_id, data, regs)) + perf_swevent_event(event, nr, nmi, data, regs); + } +end: + rcu_read_unlock(); +} + +int perf_swevent_get_recursion_context(void) +{ + struct swevent_htable *swhash = &__get_cpu_var(swevent_htable); + + return get_recursion_context(swhash->recursion); +} +EXPORT_SYMBOL_GPL(perf_swevent_get_recursion_context); + +inline void perf_swevent_put_recursion_context(int rctx) +{ + struct swevent_htable *swhash = &__get_cpu_var(swevent_htable); + + put_recursion_context(swhash->recursion, rctx); +} + +void __perf_sw_event(u32 event_id, u64 nr, int nmi, + struct pt_regs *regs, u64 addr) +{ + struct perf_sample_data data; + int rctx; + + preempt_disable_notrace(); + rctx = perf_swevent_get_recursion_context(); + if (rctx < 0) + return; + + perf_sample_data_init(&data, addr); + + do_perf_sw_event(PERF_TYPE_SOFTWARE, event_id, nr, nmi, &data, regs); + + perf_swevent_put_recursion_context(rctx); + preempt_enable_notrace(); +} + +static void perf_swevent_read(struct perf_event *event) +{ +} + +static int perf_swevent_add(struct perf_event *event, int flags) +{ + struct swevent_htable *swhash = &__get_cpu_var(swevent_htable); + struct hw_perf_event *hwc = &event->hw; + struct hlist_head *head; + + if (is_sampling_event(event)) { + hwc->last_period = hwc->sample_period; + perf_swevent_set_period(event); + } + + hwc->state = !(flags & PERF_EF_START); + + head = find_swevent_head(swhash, event); + if (WARN_ON_ONCE(!head)) + return -EINVAL; + + hlist_add_head_rcu(&event->hlist_entry, head); + + return 0; +} + +static void perf_swevent_del(struct perf_event *event, int flags) +{ + hlist_del_rcu(&event->hlist_entry); +} + +static void perf_swevent_start(struct perf_event *event, int flags) +{ + event->hw.state = 0; +} + +static void perf_swevent_stop(struct perf_event *event, int flags) +{ + event->hw.state = PERF_HES_STOPPED; +} + +/* Deref the hlist from the update side */ +static inline struct swevent_hlist * +swevent_hlist_deref(struct swevent_htable *swhash) +{ + return rcu_dereference_protected(swhash->swevent_hlist, + lockdep_is_held(&swhash->hlist_mutex)); +} + +static void swevent_hlist_release_rcu(struct rcu_head *rcu_head) +{ + struct swevent_hlist *hlist; + + hlist = container_of(rcu_head, struct swevent_hlist, rcu_head); + kfree(hlist); +} + +static void swevent_hlist_release(struct swevent_htable *swhash) +{ + struct swevent_hlist *hlist = swevent_hlist_deref(swhash); + + if (!hlist) + return; + + rcu_assign_pointer(swhash->swevent_hlist, NULL); + call_rcu(&hlist->rcu_head, swevent_hlist_release_rcu); +} + +static void swevent_hlist_put_cpu(struct perf_event *event, int cpu) +{ + struct swevent_htable *swhash = &per_cpu(swevent_htable, cpu); + + mutex_lock(&swhash->hlist_mutex); + + if (!--swhash->hlist_refcount) + swevent_hlist_release(swhash); + + mutex_unlock(&swhash->hlist_mutex); +} + +static void swevent_hlist_put(struct perf_event *event) +{ + int cpu; + + if (event->cpu != -1) { + swevent_hlist_put_cpu(event, event->cpu); + return; + } + + for_each_possible_cpu(cpu) + swevent_hlist_put_cpu(event, cpu); +} + +static int swevent_hlist_get_cpu(struct perf_event *event, int cpu) +{ + struct swevent_htable *swhash = &per_cpu(swevent_htable, cpu); + int err = 0; + + mutex_lock(&swhash->hlist_mutex); + + if (!swevent_hlist_deref(swhash) && cpu_online(cpu)) { + struct swevent_hlist *hlist; + + hlist = kzalloc(sizeof(*hlist), GFP_KERNEL); + if (!hlist) { + err = -ENOMEM; + goto exit; + } + rcu_assign_pointer(swhash->swevent_hlist, hlist); + } + swhash->hlist_refcount++; +exit: + mutex_unlock(&swhash->hlist_mutex); + + return err; +} + +static int swevent_hlist_get(struct perf_event *event) +{ + int err; + int cpu, failed_cpu; + + if (event->cpu != -1) + return swevent_hlist_get_cpu(event, event->cpu); + + get_online_cpus(); + for_each_possible_cpu(cpu) { + err = swevent_hlist_get_cpu(event, cpu); + if (err) { + failed_cpu = cpu; + goto fail; + } + } + put_online_cpus(); + + return 0; +fail: + for_each_possible_cpu(cpu) { + if (cpu == failed_cpu) + break; + swevent_hlist_put_cpu(event, cpu); + } + + put_online_cpus(); + return err; +} + +struct jump_label_key perf_swevent_enabled[PERF_COUNT_SW_MAX]; + +static void sw_perf_event_destroy(struct perf_event *event) +{ + u64 event_id = event->attr.config; + + WARN_ON(event->parent); + + jump_label_dec(&perf_swevent_enabled[event_id]); + swevent_hlist_put(event); +} + +static int perf_swevent_init(struct perf_event *event) +{ + int event_id = event->attr.config; + + if (event->attr.type != PERF_TYPE_SOFTWARE) + return -ENOENT; + + switch (event_id) { + case PERF_COUNT_SW_CPU_CLOCK: + case PERF_COUNT_SW_TASK_CLOCK: + return -ENOENT; + + default: + break; + } + + if (event_id >= PERF_COUNT_SW_MAX) + return -ENOENT; + + if (!event->parent) { + int err; + + err = swevent_hlist_get(event); + if (err) + return err; + + jump_label_inc(&perf_swevent_enabled[event_id]); + event->destroy = sw_perf_event_destroy; + } + + return 0; +} + +static struct pmu perf_swevent = { + .task_ctx_nr = perf_sw_context, + + .event_init = perf_swevent_init, + .add = perf_swevent_add, + .del = perf_swevent_del, + .start = perf_swevent_start, + .stop = perf_swevent_stop, + .read = perf_swevent_read, +}; + +#ifdef CONFIG_EVENT_TRACING + +static int perf_tp_filter_match(struct perf_event *event, + struct perf_sample_data *data) +{ + void *record = data->raw->data; + + if (likely(!event->filter) || filter_match_preds(event->filter, record)) + return 1; + return 0; +} + +static int perf_tp_event_match(struct perf_event *event, + struct perf_sample_data *data, + struct pt_regs *regs) +{ + if (event->hw.state & PERF_HES_STOPPED) + return 0; + /* + * All tracepoints are from kernel-space. + */ + if (event->attr.exclude_kernel) + return 0; + + if (!perf_tp_filter_match(event, data)) + return 0; + + return 1; +} + +void perf_tp_event(u64 addr, u64 count, void *record, int entry_size, + struct pt_regs *regs, struct hlist_head *head, int rctx) +{ + struct perf_sample_data data; + struct perf_event *event; + struct hlist_node *node; + + struct perf_raw_record raw = { + .size = entry_size, + .data = record, + }; + + perf_sample_data_init(&data, addr); + data.raw = &raw; + + hlist_for_each_entry_rcu(event, node, head, hlist_entry) { + if (perf_tp_event_match(event, &data, regs)) + perf_swevent_event(event, count, 1, &data, regs); + } + + perf_swevent_put_recursion_context(rctx); +} +EXPORT_SYMBOL_GPL(perf_tp_event); + +static void tp_perf_event_destroy(struct perf_event *event) +{ + perf_trace_destroy(event); +} + +static int perf_tp_event_init(struct perf_event *event) +{ + int err; + + if (event->attr.type != PERF_TYPE_TRACEPOINT) + return -ENOENT; + + err = perf_trace_init(event); + if (err) + return err; + + event->destroy = tp_perf_event_destroy; + + return 0; +} + +static struct pmu perf_tracepoint = { + .task_ctx_nr = perf_sw_context, + + .event_init = perf_tp_event_init, + .add = perf_trace_add, + .del = perf_trace_del, + .start = perf_swevent_start, + .stop = perf_swevent_stop, + .read = perf_swevent_read, +}; + +static inline void perf_tp_register(void) +{ + perf_pmu_register(&perf_tracepoint, "tracepoint", PERF_TYPE_TRACEPOINT); +} + +static int perf_event_set_filter(struct perf_event *event, void __user *arg) +{ + char *filter_str; + int ret; + + if (event->attr.type != PERF_TYPE_TRACEPOINT) + return -EINVAL; + + filter_str = strndup_user(arg, PAGE_SIZE); + if (IS_ERR(filter_str)) + return PTR_ERR(filter_str); + + ret = ftrace_profile_set_filter(event, event->attr.config, filter_str); + + kfree(filter_str); + return ret; +} + +static void perf_event_free_filter(struct perf_event *event) +{ + ftrace_profile_free_filter(event); +} + +#else + +static inline void perf_tp_register(void) +{ +} + +static int perf_event_set_filter(struct perf_event *event, void __user *arg) +{ + return -ENOENT; +} + +static void perf_event_free_filter(struct perf_event *event) +{ +} + +#endif /* CONFIG_EVENT_TRACING */ + +#ifdef CONFIG_HAVE_HW_BREAKPOINT +void perf_bp_event(struct perf_event *bp, void *data) +{ + struct perf_sample_data sample; + struct pt_regs *regs = data; + + perf_sample_data_init(&sample, bp->attr.bp_addr); + + if (!bp->hw.state && !perf_exclude_event(bp, regs)) + perf_swevent_event(bp, 1, 1, &sample, regs); +} +#endif + +/* + * hrtimer based swevent callback + */ + +static enum hrtimer_restart perf_swevent_hrtimer(struct hrtimer *hrtimer) +{ + enum hrtimer_restart ret = HRTIMER_RESTART; + struct perf_sample_data data; + struct pt_regs *regs; + struct perf_event *event; + u64 period; + + event = container_of(hrtimer, struct perf_event, hw.hrtimer); + + if (event->state != PERF_EVENT_STATE_ACTIVE) + return HRTIMER_NORESTART; + + event->pmu->read(event); + + perf_sample_data_init(&data, 0); + data.period = event->hw.last_period; + regs = get_irq_regs(); + + if (regs && !perf_exclude_event(event, regs)) { + if (!(event->attr.exclude_idle && current->pid == 0)) + if (perf_event_overflow(event, 0, &data, regs)) + ret = HRTIMER_NORESTART; + } + + period = max_t(u64, 10000, event->hw.sample_period); + hrtimer_forward_now(hrtimer, ns_to_ktime(period)); + + return ret; +} + +static void perf_swevent_start_hrtimer(struct perf_event *event) +{ + struct hw_perf_event *hwc = &event->hw; + s64 period; + + if (!is_sampling_event(event)) + return; + + period = local64_read(&hwc->period_left); + if (period) { + if (period < 0) + period = 10000; + + local64_set(&hwc->period_left, 0); + } else { + period = max_t(u64, 10000, hwc->sample_period); + } + __hrtimer_start_range_ns(&hwc->hrtimer, + ns_to_ktime(period), 0, + HRTIMER_MODE_REL_PINNED, 0); +} + +static void perf_swevent_cancel_hrtimer(struct perf_event *event) +{ + struct hw_perf_event *hwc = &event->hw; + + if (is_sampling_event(event)) { + ktime_t remaining = hrtimer_get_remaining(&hwc->hrtimer); + local64_set(&hwc->period_left, ktime_to_ns(remaining)); + + hrtimer_cancel(&hwc->hrtimer); + } +} + +static void perf_swevent_init_hrtimer(struct perf_event *event) +{ + struct hw_perf_event *hwc = &event->hw; + + if (!is_sampling_event(event)) + return; + + hrtimer_init(&hwc->hrtimer, CLOCK_MONOTONIC, HRTIMER_MODE_REL); + hwc->hrtimer.function = perf_swevent_hrtimer; + + /* + * Since hrtimers have a fixed rate, we can do a static freq->period + * mapping and avoid the whole period adjust feedback stuff. + */ + if (event->attr.freq) { + long freq = event->attr.sample_freq; + + event->attr.sample_period = NSEC_PER_SEC / freq; + hwc->sample_period = event->attr.sample_period; + local64_set(&hwc->period_left, hwc->sample_period); + event->attr.freq = 0; + } +} + +/* + * Software event: cpu wall time clock + */ + +static void cpu_clock_event_update(struct perf_event *event) +{ + s64 prev; + u64 now; + + now = local_clock(); + prev = local64_xchg(&event->hw.prev_count, now); + local64_add(now - prev, &event->count); +} + +static void cpu_clock_event_start(struct perf_event *event, int flags) +{ + local64_set(&event->hw.prev_count, local_clock()); + perf_swevent_start_hrtimer(event); +} + +static void cpu_clock_event_stop(struct perf_event *event, int flags) +{ + perf_swevent_cancel_hrtimer(event); + cpu_clock_event_update(event); +} + +static int cpu_clock_event_add(struct perf_event *event, int flags) +{ + if (flags & PERF_EF_START) + cpu_clock_event_start(event, flags); + + return 0; +} + +static void cpu_clock_event_del(struct perf_event *event, int flags) +{ + cpu_clock_event_stop(event, flags); +} + +static void cpu_clock_event_read(struct perf_event *event) +{ + cpu_clock_event_update(event); +} + +static int cpu_clock_event_init(struct perf_event *event) +{ + if (event->attr.type != PERF_TYPE_SOFTWARE) + return -ENOENT; + + if (event->attr.config != PERF_COUNT_SW_CPU_CLOCK) + return -ENOENT; + + perf_swevent_init_hrtimer(event); + + return 0; +} + +static struct pmu perf_cpu_clock = { + .task_ctx_nr = perf_sw_context, + + .event_init = cpu_clock_event_init, + .add = cpu_clock_event_add, + .del = cpu_clock_event_del, + .start = cpu_clock_event_start, + .stop = cpu_clock_event_stop, + .read = cpu_clock_event_read, +}; + +/* + * Software event: task time clock + */ + +static void task_clock_event_update(struct perf_event *event, u64 now) +{ + u64 prev; + s64 delta; + + prev = local64_xchg(&event->hw.prev_count, now); + delta = now - prev; + local64_add(delta, &event->count); +} + +static void task_clock_event_start(struct perf_event *event, int flags) +{ + local64_set(&event->hw.prev_count, event->ctx->time); + perf_swevent_start_hrtimer(event); +} + +static void task_clock_event_stop(struct perf_event *event, int flags) +{ + perf_swevent_cancel_hrtimer(event); + task_clock_event_update(event, event->ctx->time); +} + +static int task_clock_event_add(struct perf_event *event, int flags) +{ + if (flags & PERF_EF_START) + task_clock_event_start(event, flags); + + return 0; +} + +static void task_clock_event_del(struct perf_event *event, int flags) +{ + task_clock_event_stop(event, PERF_EF_UPDATE); +} + +static void task_clock_event_read(struct perf_event *event) +{ + u64 now = perf_clock(); + u64 delta = now - event->ctx->timestamp; + u64 time = event->ctx->time + delta; + + task_clock_event_update(event, time); +} + +static int task_clock_event_init(struct perf_event *event) +{ + if (event->attr.type != PERF_TYPE_SOFTWARE) + return -ENOENT; + + if (event->attr.config != PERF_COUNT_SW_TASK_CLOCK) + return -ENOENT; + + perf_swevent_init_hrtimer(event); + + return 0; +} + +static struct pmu perf_task_clock = { + .task_ctx_nr = perf_sw_context, + + .event_init = task_clock_event_init, + .add = task_clock_event_add, + .del = task_clock_event_del, + .start = task_clock_event_start, + .stop = task_clock_event_stop, + .read = task_clock_event_read, +}; + +static void perf_pmu_nop_void(struct pmu *pmu) +{ +} + +static int perf_pmu_nop_int(struct pmu *pmu) +{ + return 0; +} + +static void perf_pmu_start_txn(struct pmu *pmu) +{ + perf_pmu_disable(pmu); +} + +static int perf_pmu_commit_txn(struct pmu *pmu) +{ + perf_pmu_enable(pmu); + return 0; +} + +static void perf_pmu_cancel_txn(struct pmu *pmu) +{ + perf_pmu_enable(pmu); +} + +/* + * Ensures all contexts with the same task_ctx_nr have the same + * pmu_cpu_context too. + */ +static void *find_pmu_context(int ctxn) +{ + struct pmu *pmu; + + if (ctxn < 0) + return NULL; + + list_for_each_entry(pmu, &pmus, entry) { + if (pmu->task_ctx_nr == ctxn) + return pmu->pmu_cpu_context; + } + + return NULL; +} + +static void update_pmu_context(struct pmu *pmu, struct pmu *old_pmu) +{ + int cpu; + + for_each_possible_cpu(cpu) { + struct perf_cpu_context *cpuctx; + + cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu); + + if (cpuctx->active_pmu == old_pmu) + cpuctx->active_pmu = pmu; + } +} + +static void free_pmu_context(struct pmu *pmu) +{ + struct pmu *i; + + mutex_lock(&pmus_lock); + /* + * Like a real lame refcount. + */ + list_for_each_entry(i, &pmus, entry) { + if (i->pmu_cpu_context == pmu->pmu_cpu_context) { + update_pmu_context(i, pmu); + goto out; + } + } + + free_percpu(pmu->pmu_cpu_context); +out: + mutex_unlock(&pmus_lock); +} +static struct idr pmu_idr; + +static ssize_t +type_show(struct device *dev, struct device_attribute *attr, char *page) +{ + struct pmu *pmu = dev_get_drvdata(dev); + + return snprintf(page, PAGE_SIZE-1, "%d\n", pmu->type); +} + +static struct device_attribute pmu_dev_attrs[] = { + __ATTR_RO(type), + __ATTR_NULL, +}; + +static int pmu_bus_running; +static struct bus_type pmu_bus = { + .name = "event_source", + .dev_attrs = pmu_dev_attrs, +}; + +static void pmu_dev_release(struct device *dev) +{ + kfree(dev); +} + +static int pmu_dev_alloc(struct pmu *pmu) +{ + int ret = -ENOMEM; + + pmu->dev = kzalloc(sizeof(struct device), GFP_KERNEL); + if (!pmu->dev) + goto out; + + device_initialize(pmu->dev); + ret = dev_set_name(pmu->dev, "%s", pmu->name); + if (ret) + goto free_dev; + + dev_set_drvdata(pmu->dev, pmu); + pmu->dev->bus = &pmu_bus; + pmu->dev->release = pmu_dev_release; + ret = device_add(pmu->dev); + if (ret) + goto free_dev; + +out: + return ret; + +free_dev: + put_device(pmu->dev); + goto out; +} + +static struct lock_class_key cpuctx_mutex; + +int perf_pmu_register(struct pmu *pmu, char *name, int type) +{ + int cpu, ret; + + mutex_lock(&pmus_lock); + ret = -ENOMEM; + pmu->pmu_disable_count = alloc_percpu(int); + if (!pmu->pmu_disable_count) + goto unlock; + + pmu->type = -1; + if (!name) + goto skip_type; + pmu->name = name; + + if (type < 0) { + int err = idr_pre_get(&pmu_idr, GFP_KERNEL); + if (!err) + goto free_pdc; + + err = idr_get_new_above(&pmu_idr, pmu, PERF_TYPE_MAX, &type); + if (err) { + ret = err; + goto free_pdc; + } + } + pmu->type = type; + + if (pmu_bus_running) { + ret = pmu_dev_alloc(pmu); + if (ret) + goto free_idr; + } + +skip_type: + pmu->pmu_cpu_context = find_pmu_context(pmu->task_ctx_nr); + if (pmu->pmu_cpu_context) + goto got_cpu_context; + + pmu->pmu_cpu_context = alloc_percpu(struct perf_cpu_context); + if (!pmu->pmu_cpu_context) + goto free_dev; + + for_each_possible_cpu(cpu) { + struct perf_cpu_context *cpuctx; + + cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu); + __perf_event_init_context(&cpuctx->ctx); + lockdep_set_class(&cpuctx->ctx.mutex, &cpuctx_mutex); + cpuctx->ctx.type = cpu_context; + cpuctx->ctx.pmu = pmu; + cpuctx->jiffies_interval = 1; + INIT_LIST_HEAD(&cpuctx->rotation_list); + cpuctx->active_pmu = pmu; + } + +got_cpu_context: + if (!pmu->start_txn) { + if (pmu->pmu_enable) { + /* + * If we have pmu_enable/pmu_disable calls, install + * transaction stubs that use that to try and batch + * hardware accesses. + */ + pmu->start_txn = perf_pmu_start_txn; + pmu->commit_txn = perf_pmu_commit_txn; + pmu->cancel_txn = perf_pmu_cancel_txn; + } else { + pmu->start_txn = perf_pmu_nop_void; + pmu->commit_txn = perf_pmu_nop_int; + pmu->cancel_txn = perf_pmu_nop_void; + } + } + + if (!pmu->pmu_enable) { + pmu->pmu_enable = perf_pmu_nop_void; + pmu->pmu_disable = perf_pmu_nop_void; + } + + list_add_rcu(&pmu->entry, &pmus); + ret = 0; +unlock: + mutex_unlock(&pmus_lock); + + return ret; + +free_dev: + device_del(pmu->dev); + put_device(pmu->dev); + +free_idr: + if (pmu->type >= PERF_TYPE_MAX) + idr_remove(&pmu_idr, pmu->type); + +free_pdc: + free_percpu(pmu->pmu_disable_count); + goto unlock; +} + +void perf_pmu_unregister(struct pmu *pmu) +{ + mutex_lock(&pmus_lock); + list_del_rcu(&pmu->entry); + mutex_unlock(&pmus_lock); + + /* + * We dereference the pmu list under both SRCU and regular RCU, so + * synchronize against both of those. + */ + synchronize_srcu(&pmus_srcu); + synchronize_rcu(); + + free_percpu(pmu->pmu_disable_count); + if (pmu->type >= PERF_TYPE_MAX) + idr_remove(&pmu_idr, pmu->type); + device_del(pmu->dev); + put_device(pmu->dev); + free_pmu_context(pmu); +} + +struct pmu *perf_init_event(struct perf_event *event) +{ + struct pmu *pmu = NULL; + int idx; + int ret; + + idx = srcu_read_lock(&pmus_srcu); + + rcu_read_lock(); + pmu = idr_find(&pmu_idr, event->attr.type); + rcu_read_unlock(); + if (pmu) { + ret = pmu->event_init(event); + if (ret) + pmu = ERR_PTR(ret); + goto unlock; + } + + list_for_each_entry_rcu(pmu, &pmus, entry) { + ret = pmu->event_init(event); + if (!ret) + goto unlock; + + if (ret != -ENOENT) { + pmu = ERR_PTR(ret); + goto unlock; + } + } + pmu = ERR_PTR(-ENOENT); +unlock: + srcu_read_unlock(&pmus_srcu, idx); + + return pmu; +} + +/* + * Allocate and initialize a event structure + */ +static struct perf_event * +perf_event_alloc(struct perf_event_attr *attr, int cpu, + struct task_struct *task, + struct perf_event *group_leader, + struct perf_event *parent_event, + perf_overflow_handler_t overflow_handler) +{ + struct pmu *pmu; + struct perf_event *event; + struct hw_perf_event *hwc; + long err; + + if ((unsigned)cpu >= nr_cpu_ids) { + if (!task || cpu != -1) + return ERR_PTR(-EINVAL); + } + + event = kzalloc(sizeof(*event), GFP_KERNEL); + if (!event) + return ERR_PTR(-ENOMEM); + + /* + * Single events are their own group leaders, with an + * empty sibling list: + */ + if (!group_leader) + group_leader = event; + + mutex_init(&event->child_mutex); + INIT_LIST_HEAD(&event->child_list); + + INIT_LIST_HEAD(&event->group_entry); + INIT_LIST_HEAD(&event->event_entry); + INIT_LIST_HEAD(&event->sibling_list); + init_waitqueue_head(&event->waitq); + init_irq_work(&event->pending, perf_pending_event); + + mutex_init(&event->mmap_mutex); + + event->cpu = cpu; + event->attr = *attr; + event->group_leader = group_leader; + event->pmu = NULL; + event->oncpu = -1; + + event->parent = parent_event; + + event->ns = get_pid_ns(current->nsproxy->pid_ns); + event->id = atomic64_inc_return(&perf_event_id); + + event->state = PERF_EVENT_STATE_INACTIVE; + + if (task) { + event->attach_state = PERF_ATTACH_TASK; +#ifdef CONFIG_HAVE_HW_BREAKPOINT + /* + * hw_breakpoint is a bit difficult here.. + */ + if (attr->type == PERF_TYPE_BREAKPOINT) + event->hw.bp_target = task; +#endif + } + + if (!overflow_handler && parent_event) + overflow_handler = parent_event->overflow_handler; + + event->overflow_handler = overflow_handler; + + if (attr->disabled) + event->state = PERF_EVENT_STATE_OFF; + + pmu = NULL; + + hwc = &event->hw; + hwc->sample_period = attr->sample_period; + if (attr->freq && attr->sample_freq) + hwc->sample_period = 1; + hwc->last_period = hwc->sample_period; + + local64_set(&hwc->period_left, hwc->sample_period); + + /* + * we currently do not support PERF_FORMAT_GROUP on inherited events + */ + if (attr->inherit && (attr->read_format & PERF_FORMAT_GROUP)) + goto done; + + pmu = perf_init_event(event); + +done: + err = 0; + if (!pmu) + err = -EINVAL; + else if (IS_ERR(pmu)) + err = PTR_ERR(pmu); + + if (err) { + if (event->ns) + put_pid_ns(event->ns); + kfree(event); + return ERR_PTR(err); + } + + event->pmu = pmu; + + if (!event->parent) { + if (event->attach_state & PERF_ATTACH_TASK) + jump_label_inc(&perf_sched_events); + if (event->attr.mmap || event->attr.mmap_data) + atomic_inc(&nr_mmap_events); + if (event->attr.comm) + atomic_inc(&nr_comm_events); + if (event->attr.task) + atomic_inc(&nr_task_events); + if (event->attr.sample_type & PERF_SAMPLE_CALLCHAIN) { + err = get_callchain_buffers(); + if (err) { + free_event(event); + return ERR_PTR(err); + } + } + } + + return event; +} + +static int perf_copy_attr(struct perf_event_attr __user *uattr, + struct perf_event_attr *attr) +{ + u32 size; + int ret; + + if (!access_ok(VERIFY_WRITE, uattr, PERF_ATTR_SIZE_VER0)) + return -EFAULT; + + /* + * zero the full structure, so that a short copy will be nice. + */ + memset(attr, 0, sizeof(*attr)); + + ret = get_user(size, &uattr->size); + if (ret) + return ret; + + if (size > PAGE_SIZE) /* silly large */ + goto err_size; + + if (!size) /* abi compat */ + size = PERF_ATTR_SIZE_VER0; + + if (size < PERF_ATTR_SIZE_VER0) + goto err_size; + + /* + * If we're handed a bigger struct than we know of, + * ensure all the unknown bits are 0 - i.e. new + * user-space does not rely on any kernel feature + * extensions we dont know about yet. + */ + if (size > sizeof(*attr)) { + unsigned char __user *addr; + unsigned char __user *end; + unsigned char val; + + addr = (void __user *)uattr + sizeof(*attr); + end = (void __user *)uattr + size; + + for (; addr < end; addr++) { + ret = get_user(val, addr); + if (ret) + return ret; + if (val) + goto err_size; + } + size = sizeof(*attr); + } + + ret = copy_from_user(attr, uattr, size); + if (ret) + return -EFAULT; + + /* + * If the type exists, the corresponding creation will verify + * the attr->config. + */ + if (attr->type >= PERF_TYPE_MAX) + return -EINVAL; + + if (attr->__reserved_1) + return -EINVAL; + + if (attr->sample_type & ~(PERF_SAMPLE_MAX-1)) + return -EINVAL; + + if (attr->read_format & ~(PERF_FORMAT_MAX-1)) + return -EINVAL; + +out: + return ret; + +err_size: + put_user(sizeof(*attr), &uattr->size); + ret = -E2BIG; + goto out; +} + +static int +perf_event_set_output(struct perf_event *event, struct perf_event *output_event) +{ + struct perf_buffer *buffer = NULL, *old_buffer = NULL; + int ret = -EINVAL; + + if (!output_event) + goto set; + + /* don't allow circular references */ + if (event == output_event) + goto out; + + /* + * Don't allow cross-cpu buffers + */ + if (output_event->cpu != event->cpu) + goto out; + + /* + * If its not a per-cpu buffer, it must be the same task. + */ + if (output_event->cpu == -1 && output_event->ctx != event->ctx) + goto out; + +set: + mutex_lock(&event->mmap_mutex); + /* Can't redirect output if we've got an active mmap() */ + if (atomic_read(&event->mmap_count)) + goto unlock; + + if (output_event) { + /* get the buffer we want to redirect to */ + buffer = perf_buffer_get(output_event); + if (!buffer) + goto unlock; + } + + old_buffer = event->buffer; + rcu_assign_pointer(event->buffer, buffer); + ret = 0; +unlock: + mutex_unlock(&event->mmap_mutex); + + if (old_buffer) + perf_buffer_put(old_buffer); +out: + return ret; +} + +/** + * sys_perf_event_open - open a performance event, associate it to a task/cpu + * + * @attr_uptr: event_id type attributes for monitoring/sampling + * @pid: target pid + * @cpu: target cpu + * @group_fd: group leader event fd + */ +SYSCALL_DEFINE5(perf_event_open, + struct perf_event_attr __user *, attr_uptr, + pid_t, pid, int, cpu, int, group_fd, unsigned long, flags) +{ + struct perf_event *group_leader = NULL, *output_event = NULL; + struct perf_event *event, *sibling; + struct perf_event_attr attr; + struct perf_event_context *ctx; + struct file *event_file = NULL; + struct file *group_file = NULL; + struct task_struct *task = NULL; + struct pmu *pmu; + int event_fd; + int move_group = 0; + int fput_needed = 0; + int err; + + /* for future expandability... */ + if (flags & ~PERF_FLAG_ALL) + return -EINVAL; + + err = perf_copy_attr(attr_uptr, &attr); + if (err) + return err; + + if (!attr.exclude_kernel) { + if (perf_paranoid_kernel() && !capable(CAP_SYS_ADMIN)) + return -EACCES; + } + + if (attr.freq) { + if (attr.sample_freq > sysctl_perf_event_sample_rate) + return -EINVAL; + } + + /* + * In cgroup mode, the pid argument is used to pass the fd + * opened to the cgroup directory in cgroupfs. The cpu argument + * designates the cpu on which to monitor threads from that + * cgroup. + */ + if ((flags & PERF_FLAG_PID_CGROUP) && (pid == -1 || cpu == -1)) + return -EINVAL; + + event_fd = get_unused_fd_flags(O_RDWR); + if (event_fd < 0) + return event_fd; + + if (group_fd != -1) { + group_leader = perf_fget_light(group_fd, &fput_needed); + if (IS_ERR(group_leader)) { + err = PTR_ERR(group_leader); + goto err_fd; + } + group_file = group_leader->filp; + if (flags & PERF_FLAG_FD_OUTPUT) + output_event = group_leader; + if (flags & PERF_FLAG_FD_NO_GROUP) + group_leader = NULL; + } + + if (pid != -1 && !(flags & PERF_FLAG_PID_CGROUP)) { + task = find_lively_task_by_vpid(pid); + if (IS_ERR(task)) { + err = PTR_ERR(task); + goto err_group_fd; + } + } + + event = perf_event_alloc(&attr, cpu, task, group_leader, NULL, NULL); + if (IS_ERR(event)) { + err = PTR_ERR(event); + goto err_task; + } + + if (flags & PERF_FLAG_PID_CGROUP) { + err = perf_cgroup_connect(pid, event, &attr, group_leader); + if (err) + goto err_alloc; + /* + * one more event: + * - that has cgroup constraint on event->cpu + * - that may need work on context switch + */ + atomic_inc(&per_cpu(perf_cgroup_events, event->cpu)); + jump_label_inc(&perf_sched_events); + } + + /* + * Special case software events and allow them to be part of + * any hardware group. + */ + pmu = event->pmu; + + if (group_leader && + (is_software_event(event) != is_software_event(group_leader))) { + if (is_software_event(event)) { + /* + * If event and group_leader are not both a software + * event, and event is, then group leader is not. + * + * Allow the addition of software events to !software + * groups, this is safe because software events never + * fail to schedule. + */ + pmu = group_leader->pmu; + } else if (is_software_event(group_leader) && + (group_leader->group_flags & PERF_GROUP_SOFTWARE)) { + /* + * In case the group is a pure software group, and we + * try to add a hardware event, move the whole group to + * the hardware context. + */ + move_group = 1; + } + } + + /* + * Get the target context (task or percpu): + */ + ctx = find_get_context(pmu, task, cpu); + if (IS_ERR(ctx)) { + err = PTR_ERR(ctx); + goto err_alloc; + } + + if (task) { + put_task_struct(task); + task = NULL; + } + + /* + * Look up the group leader (we will attach this event to it): + */ + if (group_leader) { + err = -EINVAL; + + /* + * Do not allow a recursive hierarchy (this new sibling + * becoming part of another group-sibling): + */ + if (group_leader->group_leader != group_leader) + goto err_context; + /* + * Do not allow to attach to a group in a different + * task or CPU context: + */ + if (move_group) { + if (group_leader->ctx->type != ctx->type) + goto err_context; + } else { + if (group_leader->ctx != ctx) + goto err_context; + } + + /* + * Only a group leader can be exclusive or pinned + */ + if (attr.exclusive || attr.pinned) + goto err_context; + } + + if (output_event) { + err = perf_event_set_output(event, output_event); + if (err) + goto err_context; + } + + event_file = anon_inode_getfile("[perf_event]", &perf_fops, event, O_RDWR); + if (IS_ERR(event_file)) { + err = PTR_ERR(event_file); + goto err_context; + } + + if (move_group) { + struct perf_event_context *gctx = group_leader->ctx; + + mutex_lock(&gctx->mutex); + perf_remove_from_context(group_leader); + list_for_each_entry(sibling, &group_leader->sibling_list, + group_entry) { + perf_remove_from_context(sibling); + put_ctx(gctx); + } + mutex_unlock(&gctx->mutex); + put_ctx(gctx); + } + + event->filp = event_file; + WARN_ON_ONCE(ctx->parent_ctx); + mutex_lock(&ctx->mutex); + + if (move_group) { + perf_install_in_context(ctx, group_leader, cpu); + get_ctx(ctx); + list_for_each_entry(sibling, &group_leader->sibling_list, + group_entry) { + perf_install_in_context(ctx, sibling, cpu); + get_ctx(ctx); + } + } + + perf_install_in_context(ctx, event, cpu); + ++ctx->generation; + perf_unpin_context(ctx); + mutex_unlock(&ctx->mutex); + + event->owner = current; + + mutex_lock(¤t->perf_event_mutex); + list_add_tail(&event->owner_entry, ¤t->perf_event_list); + mutex_unlock(¤t->perf_event_mutex); + + /* + * Precalculate sample_data sizes + */ + perf_event__header_size(event); + perf_event__id_header_size(event); + + /* + * Drop the reference on the group_event after placing the + * new event on the sibling_list. This ensures destruction + * of the group leader will find the pointer to itself in + * perf_group_detach(). + */ + fput_light(group_file, fput_needed); + fd_install(event_fd, event_file); + return event_fd; + +err_context: + perf_unpin_context(ctx); + put_ctx(ctx); +err_alloc: + free_event(event); +err_task: + if (task) + put_task_struct(task); +err_group_fd: + fput_light(group_file, fput_needed); +err_fd: + put_unused_fd(event_fd); + return err; +} + +/** + * perf_event_create_kernel_counter + * + * @attr: attributes of the counter to create + * @cpu: cpu in which the counter is bound + * @task: task to profile (NULL for percpu) + */ +struct perf_event * +perf_event_create_kernel_counter(struct perf_event_attr *attr, int cpu, + struct task_struct *task, + perf_overflow_handler_t overflow_handler) +{ + struct perf_event_context *ctx; + struct perf_event *event; + int err; + + /* + * Get the target context (task or percpu): + */ + + event = perf_event_alloc(attr, cpu, task, NULL, NULL, overflow_handler); + if (IS_ERR(event)) { + err = PTR_ERR(event); + goto err; + } + + ctx = find_get_context(event->pmu, task, cpu); + if (IS_ERR(ctx)) { + err = PTR_ERR(ctx); + goto err_free; + } + + event->filp = NULL; + WARN_ON_ONCE(ctx->parent_ctx); + mutex_lock(&ctx->mutex); + perf_install_in_context(ctx, event, cpu); + ++ctx->generation; + perf_unpin_context(ctx); + mutex_unlock(&ctx->mutex); + + return event; + +err_free: + free_event(event); +err: + return ERR_PTR(err); +} +EXPORT_SYMBOL_GPL(perf_event_create_kernel_counter); + +static void sync_child_event(struct perf_event *child_event, + struct task_struct *child) +{ + struct perf_event *parent_event = child_event->parent; + u64 child_val; + + if (child_event->attr.inherit_stat) + perf_event_read_event(child_event, child); + + child_val = perf_event_count(child_event); + + /* + * Add back the child's count to the parent's count: + */ + atomic64_add(child_val, &parent_event->child_count); + atomic64_add(child_event->total_time_enabled, + &parent_event->child_total_time_enabled); + atomic64_add(child_event->total_time_running, + &parent_event->child_total_time_running); + + /* + * Remove this event from the parent's list + */ + WARN_ON_ONCE(parent_event->ctx->parent_ctx); + mutex_lock(&parent_event->child_mutex); + list_del_init(&child_event->child_list); + mutex_unlock(&parent_event->child_mutex); + + /* + * Release the parent event, if this was the last + * reference to it. + */ + fput(parent_event->filp); +} + +static void +__perf_event_exit_task(struct perf_event *child_event, + struct perf_event_context *child_ctx, + struct task_struct *child) +{ + if (child_event->parent) { + raw_spin_lock_irq(&child_ctx->lock); + perf_group_detach(child_event); + raw_spin_unlock_irq(&child_ctx->lock); + } + + perf_remove_from_context(child_event); + + /* + * It can happen that the parent exits first, and has events + * that are still around due to the child reference. These + * events need to be zapped. + */ + if (child_event->parent) { + sync_child_event(child_event, child); + free_event(child_event); + } +} + +static void perf_event_exit_task_context(struct task_struct *child, int ctxn) +{ + struct perf_event *child_event, *tmp; + struct perf_event_context *child_ctx; + unsigned long flags; + + if (likely(!child->perf_event_ctxp[ctxn])) { + perf_event_task(child, NULL, 0); + return; + } + + local_irq_save(flags); + /* + * We can't reschedule here because interrupts are disabled, + * and either child is current or it is a task that can't be + * scheduled, so we are now safe from rescheduling changing + * our context. + */ + child_ctx = rcu_dereference_raw(child->perf_event_ctxp[ctxn]); + task_ctx_sched_out(child_ctx, EVENT_ALL); + + /* + * Take the context lock here so that if find_get_context is + * reading child->perf_event_ctxp, we wait until it has + * incremented the context's refcount before we do put_ctx below. + */ + raw_spin_lock(&child_ctx->lock); + child->perf_event_ctxp[ctxn] = NULL; + /* + * If this context is a clone; unclone it so it can't get + * swapped to another process while we're removing all + * the events from it. + */ + unclone_ctx(child_ctx); + update_context_time(child_ctx); + raw_spin_unlock_irqrestore(&child_ctx->lock, flags); + + /* + * Report the task dead after unscheduling the events so that we + * won't get any samples after PERF_RECORD_EXIT. We can however still + * get a few PERF_RECORD_READ events. + */ + perf_event_task(child, child_ctx, 0); + + /* + * We can recurse on the same lock type through: + * + * __perf_event_exit_task() + * sync_child_event() + * fput(parent_event->filp) + * perf_release() + * mutex_lock(&ctx->mutex) + * + * But since its the parent context it won't be the same instance. + */ + mutex_lock(&child_ctx->mutex); + +again: + list_for_each_entry_safe(child_event, tmp, &child_ctx->pinned_groups, + group_entry) + __perf_event_exit_task(child_event, child_ctx, child); + + list_for_each_entry_safe(child_event, tmp, &child_ctx->flexible_groups, + group_entry) + __perf_event_exit_task(child_event, child_ctx, child); + + /* + * If the last event was a group event, it will have appended all + * its siblings to the list, but we obtained 'tmp' before that which + * will still point to the list head terminating the iteration. + */ + if (!list_empty(&child_ctx->pinned_groups) || + !list_empty(&child_ctx->flexible_groups)) + goto again; + + mutex_unlock(&child_ctx->mutex); + + put_ctx(child_ctx); +} + +/* + * When a child task exits, feed back event values to parent events. + */ +void perf_event_exit_task(struct task_struct *child) +{ + struct perf_event *event, *tmp; + int ctxn; + + mutex_lock(&child->perf_event_mutex); + list_for_each_entry_safe(event, tmp, &child->perf_event_list, + owner_entry) { + list_del_init(&event->owner_entry); + + /* + * Ensure the list deletion is visible before we clear + * the owner, closes a race against perf_release() where + * we need to serialize on the owner->perf_event_mutex. + */ + smp_wmb(); + event->owner = NULL; + } + mutex_unlock(&child->perf_event_mutex); + + for_each_task_context_nr(ctxn) + perf_event_exit_task_context(child, ctxn); +} + +static void perf_free_event(struct perf_event *event, + struct perf_event_context *ctx) +{ + struct perf_event *parent = event->parent; + + if (WARN_ON_ONCE(!parent)) + return; + + mutex_lock(&parent->child_mutex); + list_del_init(&event->child_list); + mutex_unlock(&parent->child_mutex); + + fput(parent->filp); + + perf_group_detach(event); + list_del_event(event, ctx); + free_event(event); +} + +/* + * free an unexposed, unused context as created by inheritance by + * perf_event_init_task below, used by fork() in case of fail. + */ +void perf_event_free_task(struct task_struct *task) +{ + struct perf_event_context *ctx; + struct perf_event *event, *tmp; + int ctxn; + + for_each_task_context_nr(ctxn) { + ctx = task->perf_event_ctxp[ctxn]; + if (!ctx) + continue; + + mutex_lock(&ctx->mutex); +again: + list_for_each_entry_safe(event, tmp, &ctx->pinned_groups, + group_entry) + perf_free_event(event, ctx); + + list_for_each_entry_safe(event, tmp, &ctx->flexible_groups, + group_entry) + perf_free_event(event, ctx); + + if (!list_empty(&ctx->pinned_groups) || + !list_empty(&ctx->flexible_groups)) + goto again; + + mutex_unlock(&ctx->mutex); + + put_ctx(ctx); + } +} + +void perf_event_delayed_put(struct task_struct *task) +{ + int ctxn; + + for_each_task_context_nr(ctxn) + WARN_ON_ONCE(task->perf_event_ctxp[ctxn]); +} + +/* + * inherit a event from parent task to child task: + */ +static struct perf_event * +inherit_event(struct perf_event *parent_event, + struct task_struct *parent, + struct perf_event_context *parent_ctx, + struct task_struct *child, + struct perf_event *group_leader, + struct perf_event_context *child_ctx) +{ + struct perf_event *child_event; + unsigned long flags; + + /* + * Instead of creating recursive hierarchies of events, + * we link inherited events back to the original parent, + * which has a filp for sure, which we use as the reference + * count: + */ + if (parent_event->parent) + parent_event = parent_event->parent; + + child_event = perf_event_alloc(&parent_event->attr, + parent_event->cpu, + child, + group_leader, parent_event, + NULL); + if (IS_ERR(child_event)) + return child_event; + get_ctx(child_ctx); + + /* + * Make the child state follow the state of the parent event, + * not its attr.disabled bit. We hold the parent's mutex, + * so we won't race with perf_event_{en, dis}able_family. + */ + if (parent_event->state >= PERF_EVENT_STATE_INACTIVE) + child_event->state = PERF_EVENT_STATE_INACTIVE; + else + child_event->state = PERF_EVENT_STATE_OFF; + + if (parent_event->attr.freq) { + u64 sample_period = parent_event->hw.sample_period; + struct hw_perf_event *hwc = &child_event->hw; + + hwc->sample_period = sample_period; + hwc->last_period = sample_period; + + local64_set(&hwc->period_left, sample_period); + } + + child_event->ctx = child_ctx; + child_event->overflow_handler = parent_event->overflow_handler; + + /* + * Precalculate sample_data sizes + */ + perf_event__header_size(child_event); + perf_event__id_header_size(child_event); + + /* + * Link it up in the child's context: + */ + raw_spin_lock_irqsave(&child_ctx->lock, flags); + add_event_to_ctx(child_event, child_ctx); + raw_spin_unlock_irqrestore(&child_ctx->lock, flags); + + /* + * Get a reference to the parent filp - we will fput it + * when the child event exits. This is safe to do because + * we are in the parent and we know that the filp still + * exists and has a nonzero count: + */ + atomic_long_inc(&parent_event->filp->f_count); + + /* + * Link this into the parent event's child list + */ + WARN_ON_ONCE(parent_event->ctx->parent_ctx); + mutex_lock(&parent_event->child_mutex); + list_add_tail(&child_event->child_list, &parent_event->child_list); + mutex_unlock(&parent_event->child_mutex); + + return child_event; +} + +static int inherit_group(struct perf_event *parent_event, + struct task_struct *parent, + struct perf_event_context *parent_ctx, + struct task_struct *child, + struct perf_event_context *child_ctx) +{ + struct perf_event *leader; + struct perf_event *sub; + struct perf_event *child_ctr; + + leader = inherit_event(parent_event, parent, parent_ctx, + child, NULL, child_ctx); + if (IS_ERR(leader)) + return PTR_ERR(leader); + list_for_each_entry(sub, &parent_event->sibling_list, group_entry) { + child_ctr = inherit_event(sub, parent, parent_ctx, + child, leader, child_ctx); + if (IS_ERR(child_ctr)) + return PTR_ERR(child_ctr); + } + return 0; +} + +static int +inherit_task_group(struct perf_event *event, struct task_struct *parent, + struct perf_event_context *parent_ctx, + struct task_struct *child, int ctxn, + int *inherited_all) +{ + int ret; + struct perf_event_context *child_ctx; + + if (!event->attr.inherit) { + *inherited_all = 0; + return 0; + } + + child_ctx = child->perf_event_ctxp[ctxn]; + if (!child_ctx) { + /* + * This is executed from the parent task context, so + * inherit events that have been marked for cloning. + * First allocate and initialize a context for the + * child. + */ + + child_ctx = alloc_perf_context(event->pmu, child); + if (!child_ctx) + return -ENOMEM; + + child->perf_event_ctxp[ctxn] = child_ctx; + } + + ret = inherit_group(event, parent, parent_ctx, + child, child_ctx); + + if (ret) + *inherited_all = 0; + + return ret; +} + +/* + * Initialize the perf_event context in task_struct + */ +int perf_event_init_context(struct task_struct *child, int ctxn) +{ + struct perf_event_context *child_ctx, *parent_ctx; + struct perf_event_context *cloned_ctx; + struct perf_event *event; + struct task_struct *parent = current; + int inherited_all = 1; + unsigned long flags; + int ret = 0; + + if (likely(!parent->perf_event_ctxp[ctxn])) + return 0; + + /* + * If the parent's context is a clone, pin it so it won't get + * swapped under us. + */ + parent_ctx = perf_pin_task_context(parent, ctxn); + + /* + * No need to check if parent_ctx != NULL here; since we saw + * it non-NULL earlier, the only reason for it to become NULL + * is if we exit, and since we're currently in the middle of + * a fork we can't be exiting at the same time. + */ + + /* + * Lock the parent list. No need to lock the child - not PID + * hashed yet and not running, so nobody can access it. + */ + mutex_lock(&parent_ctx->mutex); + + /* + * We dont have to disable NMIs - we are only looking at + * the list, not manipulating it: + */ + list_for_each_entry(event, &parent_ctx->pinned_groups, group_entry) { + ret = inherit_task_group(event, parent, parent_ctx, + child, ctxn, &inherited_all); + if (ret) + break; + } + + /* + * We can't hold ctx->lock when iterating the ->flexible_group list due + * to allocations, but we need to prevent rotation because + * rotate_ctx() will change the list from interrupt context. + */ + raw_spin_lock_irqsave(&parent_ctx->lock, flags); + parent_ctx->rotate_disable = 1; + raw_spin_unlock_irqrestore(&parent_ctx->lock, flags); + + list_for_each_entry(event, &parent_ctx->flexible_groups, group_entry) { + ret = inherit_task_group(event, parent, parent_ctx, + child, ctxn, &inherited_all); + if (ret) + break; + } + + raw_spin_lock_irqsave(&parent_ctx->lock, flags); + parent_ctx->rotate_disable = 0; + + child_ctx = child->perf_event_ctxp[ctxn]; + + if (child_ctx && inherited_all) { + /* + * Mark the child context as a clone of the parent + * context, or of whatever the parent is a clone of. + * + * Note that if the parent is a clone, the holding of + * parent_ctx->lock avoids it from being uncloned. + */ + cloned_ctx = parent_ctx->parent_ctx; + if (cloned_ctx) { + child_ctx->parent_ctx = cloned_ctx; + child_ctx->parent_gen = parent_ctx->parent_gen; + } else { + child_ctx->parent_ctx = parent_ctx; + child_ctx->parent_gen = parent_ctx->generation; + } + get_ctx(child_ctx->parent_ctx); + } + + raw_spin_unlock_irqrestore(&parent_ctx->lock, flags); + mutex_unlock(&parent_ctx->mutex); + + perf_unpin_context(parent_ctx); + put_ctx(parent_ctx); + + return ret; +} + +/* + * Initialize the perf_event context in task_struct + */ +int perf_event_init_task(struct task_struct *child) +{ + int ctxn, ret; + + memset(child->perf_event_ctxp, 0, sizeof(child->perf_event_ctxp)); + mutex_init(&child->perf_event_mutex); + INIT_LIST_HEAD(&child->perf_event_list); + + for_each_task_context_nr(ctxn) { + ret = perf_event_init_context(child, ctxn); + if (ret) + return ret; + } + + return 0; +} + +static void __init perf_event_init_all_cpus(void) +{ + struct swevent_htable *swhash; + int cpu; + + for_each_possible_cpu(cpu) { + swhash = &per_cpu(swevent_htable, cpu); + mutex_init(&swhash->hlist_mutex); + INIT_LIST_HEAD(&per_cpu(rotation_list, cpu)); + } +} + +static void __cpuinit perf_event_init_cpu(int cpu) +{ + struct swevent_htable *swhash = &per_cpu(swevent_htable, cpu); + + mutex_lock(&swhash->hlist_mutex); + if (swhash->hlist_refcount > 0) { + struct swevent_hlist *hlist; + + hlist = kzalloc_node(sizeof(*hlist), GFP_KERNEL, cpu_to_node(cpu)); + WARN_ON(!hlist); + rcu_assign_pointer(swhash->swevent_hlist, hlist); + } + mutex_unlock(&swhash->hlist_mutex); +} + +#if defined CONFIG_HOTPLUG_CPU || defined CONFIG_KEXEC +static void perf_pmu_rotate_stop(struct pmu *pmu) +{ + struct perf_cpu_context *cpuctx = this_cpu_ptr(pmu->pmu_cpu_context); + + WARN_ON(!irqs_disabled()); + + list_del_init(&cpuctx->rotation_list); +} + +static void __perf_event_exit_context(void *__info) +{ + struct perf_event_context *ctx = __info; + struct perf_event *event, *tmp; + + perf_pmu_rotate_stop(ctx->pmu); + + list_for_each_entry_safe(event, tmp, &ctx->pinned_groups, group_entry) + __perf_remove_from_context(event); + list_for_each_entry_safe(event, tmp, &ctx->flexible_groups, group_entry) + __perf_remove_from_context(event); +} + +static void perf_event_exit_cpu_context(int cpu) +{ + struct perf_event_context *ctx; + struct pmu *pmu; + int idx; + + idx = srcu_read_lock(&pmus_srcu); + list_for_each_entry_rcu(pmu, &pmus, entry) { + ctx = &per_cpu_ptr(pmu->pmu_cpu_context, cpu)->ctx; + + mutex_lock(&ctx->mutex); + smp_call_function_single(cpu, __perf_event_exit_context, ctx, 1); + mutex_unlock(&ctx->mutex); + } + srcu_read_unlock(&pmus_srcu, idx); +} + +static void perf_event_exit_cpu(int cpu) +{ + struct swevent_htable *swhash = &per_cpu(swevent_htable, cpu); + + mutex_lock(&swhash->hlist_mutex); + swevent_hlist_release(swhash); + mutex_unlock(&swhash->hlist_mutex); + + perf_event_exit_cpu_context(cpu); +} +#else +static inline void perf_event_exit_cpu(int cpu) { } +#endif + +static int +perf_reboot(struct notifier_block *notifier, unsigned long val, void *v) +{ + int cpu; + + for_each_online_cpu(cpu) + perf_event_exit_cpu(cpu); + + return NOTIFY_OK; +} + +/* + * Run the perf reboot notifier at the very last possible moment so that + * the generic watchdog code runs as long as possible. + */ +static struct notifier_block perf_reboot_notifier = { + .notifier_call = perf_reboot, + .priority = INT_MIN, +}; + +static int __cpuinit +perf_cpu_notify(struct notifier_block *self, unsigned long action, void *hcpu) +{ + unsigned int cpu = (long)hcpu; + + switch (action & ~CPU_TASKS_FROZEN) { + + case CPU_UP_PREPARE: + case CPU_DOWN_FAILED: + perf_event_init_cpu(cpu); + break; + + case CPU_UP_CANCELED: + case CPU_DOWN_PREPARE: + perf_event_exit_cpu(cpu); + break; + + default: + break; + } + + return NOTIFY_OK; +} + +void __init perf_event_init(void) +{ + int ret; + + idr_init(&pmu_idr); + + perf_event_init_all_cpus(); + init_srcu_struct(&pmus_srcu); + perf_pmu_register(&perf_swevent, "software", PERF_TYPE_SOFTWARE); + perf_pmu_register(&perf_cpu_clock, NULL, -1); + perf_pmu_register(&perf_task_clock, NULL, -1); + perf_tp_register(); + perf_cpu_notifier(perf_cpu_notify); + register_reboot_notifier(&perf_reboot_notifier); + + ret = init_hw_breakpoint(); + WARN(ret, "hw_breakpoint initialization failed with: %d", ret); +} + +static int __init perf_event_sysfs_init(void) +{ + struct pmu *pmu; + int ret; + + mutex_lock(&pmus_lock); + + ret = bus_register(&pmu_bus); + if (ret) + goto unlock; + + list_for_each_entry(pmu, &pmus, entry) { + if (!pmu->name || pmu->type < 0) + continue; + + ret = pmu_dev_alloc(pmu); + WARN(ret, "Failed to register pmu: %s, reason %d\n", pmu->name, ret); + } + pmu_bus_running = 1; + ret = 0; + +unlock: + mutex_unlock(&pmus_lock); + + return ret; +} +device_initcall(perf_event_sysfs_init); + +#ifdef CONFIG_CGROUP_PERF +static struct cgroup_subsys_state *perf_cgroup_create( + struct cgroup_subsys *ss, struct cgroup *cont) +{ + struct perf_cgroup *jc; + + jc = kzalloc(sizeof(*jc), GFP_KERNEL); + if (!jc) + return ERR_PTR(-ENOMEM); + + jc->info = alloc_percpu(struct perf_cgroup_info); + if (!jc->info) { + kfree(jc); + return ERR_PTR(-ENOMEM); + } + + return &jc->css; +} + +static void perf_cgroup_destroy(struct cgroup_subsys *ss, + struct cgroup *cont) +{ + struct perf_cgroup *jc; + jc = container_of(cgroup_subsys_state(cont, perf_subsys_id), + struct perf_cgroup, css); + free_percpu(jc->info); + kfree(jc); +} + +static int __perf_cgroup_move(void *info) +{ + struct task_struct *task = info; + perf_cgroup_switch(task, PERF_CGROUP_SWOUT | PERF_CGROUP_SWIN); + return 0; +} + +static void perf_cgroup_move(struct task_struct *task) +{ + task_function_call(task, __perf_cgroup_move, task); +} + +static void perf_cgroup_attach(struct cgroup_subsys *ss, struct cgroup *cgrp, + struct cgroup *old_cgrp, struct task_struct *task, + bool threadgroup) +{ + perf_cgroup_move(task); + if (threadgroup) { + struct task_struct *c; + rcu_read_lock(); + list_for_each_entry_rcu(c, &task->thread_group, thread_group) { + perf_cgroup_move(c); + } + rcu_read_unlock(); + } +} + +static void perf_cgroup_exit(struct cgroup_subsys *ss, struct cgroup *cgrp, + struct cgroup *old_cgrp, struct task_struct *task) +{ + /* + * cgroup_exit() is called in the copy_process() failure path. + * Ignore this case since the task hasn't ran yet, this avoids + * trying to poke a half freed task state from generic code. + */ + if (!(task->flags & PF_EXITING)) + return; + + perf_cgroup_move(task); +} + +struct cgroup_subsys perf_subsys = { + .name = "perf_event", + .subsys_id = perf_subsys_id, + .create = perf_cgroup_create, + .destroy = perf_cgroup_destroy, + .exit = perf_cgroup_exit, + .attach = perf_cgroup_attach, +}; +#endif /* CONFIG_CGROUP_PERF */ diff --git a/kernel/perf_event.c b/kernel/perf_event.c deleted file mode 100644 index 440bc48..0000000 --- a/kernel/perf_event.c +++ /dev/null @@ -1,7455 +0,0 @@ -/* - * Performance events core code: - * - * Copyright (C) 2008 Thomas Gleixner - * Copyright (C) 2008-2009 Red Hat, Inc., Ingo Molnar - * Copyright (C) 2008-2009 Red Hat, Inc., Peter Zijlstra - * Copyright © 2009 Paul Mackerras, IBM Corp. - * - * For licensing details see kernel-base/COPYING - */ - -#include -#include -#include -#include -#include -#include -#include -#include -#include -#include -#include -#include -#include -#include -#include -#include -#include -#include -#include -#include -#include -#include -#include -#include -#include -#include - -#include - -struct remote_function_call { - struct task_struct *p; - int (*func)(void *info); - void *info; - int ret; -}; - -static void remote_function(void *data) -{ - struct remote_function_call *tfc = data; - struct task_struct *p = tfc->p; - - if (p) { - tfc->ret = -EAGAIN; - if (task_cpu(p) != smp_processor_id() || !task_curr(p)) - return; - } - - tfc->ret = tfc->func(tfc->info); -} - -/** - * task_function_call - call a function on the cpu on which a task runs - * @p: the task to evaluate - * @func: the function to be called - * @info: the function call argument - * - * Calls the function @func when the task is currently running. This might - * be on the current CPU, which just calls the function directly - * - * returns: @func return value, or - * -ESRCH - when the process isn't running - * -EAGAIN - when the process moved away - */ -static int -task_function_call(struct task_struct *p, int (*func) (void *info), void *info) -{ - struct remote_function_call data = { - .p = p, - .func = func, - .info = info, - .ret = -ESRCH, /* No such (running) process */ - }; - - if (task_curr(p)) - smp_call_function_single(task_cpu(p), remote_function, &data, 1); - - return data.ret; -} - -/** - * cpu_function_call - call a function on the cpu - * @func: the function to be called - * @info: the function call argument - * - * Calls the function @func on the remote cpu. - * - * returns: @func return value or -ENXIO when the cpu is offline - */ -static int cpu_function_call(int cpu, int (*func) (void *info), void *info) -{ - struct remote_function_call data = { - .p = NULL, - .func = func, - .info = info, - .ret = -ENXIO, /* No such CPU */ - }; - - smp_call_function_single(cpu, remote_function, &data, 1); - - return data.ret; -} - -#define PERF_FLAG_ALL (PERF_FLAG_FD_NO_GROUP |\ - PERF_FLAG_FD_OUTPUT |\ - PERF_FLAG_PID_CGROUP) - -enum event_type_t { - EVENT_FLEXIBLE = 0x1, - EVENT_PINNED = 0x2, - EVENT_ALL = EVENT_FLEXIBLE | EVENT_PINNED, -}; - -/* - * perf_sched_events : >0 events exist - * perf_cgroup_events: >0 per-cpu cgroup events exist on this cpu - */ -struct jump_label_key perf_sched_events __read_mostly; -static DEFINE_PER_CPU(atomic_t, perf_cgroup_events); - -static atomic_t nr_mmap_events __read_mostly; -static atomic_t nr_comm_events __read_mostly; -static atomic_t nr_task_events __read_mostly; - -static LIST_HEAD(pmus); -static DEFINE_MUTEX(pmus_lock); -static struct srcu_struct pmus_srcu; - -/* - * perf event paranoia level: - * -1 - not paranoid at all - * 0 - disallow raw tracepoint access for unpriv - * 1 - disallow cpu events for unpriv - * 2 - disallow kernel profiling for unpriv - */ -int sysctl_perf_event_paranoid __read_mostly = 1; - -/* Minimum for 512 kiB + 1 user control page */ -int sysctl_perf_event_mlock __read_mostly = 512 + (PAGE_SIZE / 1024); /* 'free' kiB per user */ - -/* - * max perf event sample rate - */ -#define DEFAULT_MAX_SAMPLE_RATE 100000 -int sysctl_perf_event_sample_rate __read_mostly = DEFAULT_MAX_SAMPLE_RATE; -static int max_samples_per_tick __read_mostly = - DIV_ROUND_UP(DEFAULT_MAX_SAMPLE_RATE, HZ); - -int perf_proc_update_handler(struct ctl_table *table, int write, - void __user *buffer, size_t *lenp, - loff_t *ppos) -{ - int ret = proc_dointvec(table, write, buffer, lenp, ppos); - - if (ret || !write) - return ret; - - max_samples_per_tick = DIV_ROUND_UP(sysctl_perf_event_sample_rate, HZ); - - return 0; -} - -static atomic64_t perf_event_id; - -static void cpu_ctx_sched_out(struct perf_cpu_context *cpuctx, - enum event_type_t event_type); - -static void cpu_ctx_sched_in(struct perf_cpu_context *cpuctx, - enum event_type_t event_type, - struct task_struct *task); - -static void update_context_time(struct perf_event_context *ctx); -static u64 perf_event_time(struct perf_event *event); - -void __weak perf_event_print_debug(void) { } - -extern __weak const char *perf_pmu_name(void) -{ - return "pmu"; -} - -static inline u64 perf_clock(void) -{ - return local_clock(); -} - -static inline struct perf_cpu_context * -__get_cpu_context(struct perf_event_context *ctx) -{ - return this_cpu_ptr(ctx->pmu->pmu_cpu_context); -} - -#ifdef CONFIG_CGROUP_PERF - -/* - * Must ensure cgroup is pinned (css_get) before calling - * this function. In other words, we cannot call this function - * if there is no cgroup event for the current CPU context. - */ -static inline struct perf_cgroup * -perf_cgroup_from_task(struct task_struct *task) -{ - return container_of(task_subsys_state(task, perf_subsys_id), - struct perf_cgroup, css); -} - -static inline bool -perf_cgroup_match(struct perf_event *event) -{ - struct perf_event_context *ctx = event->ctx; - struct perf_cpu_context *cpuctx = __get_cpu_context(ctx); - - return !event->cgrp || event->cgrp == cpuctx->cgrp; -} - -static inline void perf_get_cgroup(struct perf_event *event) -{ - css_get(&event->cgrp->css); -} - -static inline void perf_put_cgroup(struct perf_event *event) -{ - css_put(&event->cgrp->css); -} - -static inline void perf_detach_cgroup(struct perf_event *event) -{ - perf_put_cgroup(event); - event->cgrp = NULL; -} - -static inline int is_cgroup_event(struct perf_event *event) -{ - return event->cgrp != NULL; -} - -static inline u64 perf_cgroup_event_time(struct perf_event *event) -{ - struct perf_cgroup_info *t; - - t = per_cpu_ptr(event->cgrp->info, event->cpu); - return t->time; -} - -static inline void __update_cgrp_time(struct perf_cgroup *cgrp) -{ - struct perf_cgroup_info *info; - u64 now; - - now = perf_clock(); - - info = this_cpu_ptr(cgrp->info); - - info->time += now - info->timestamp; - info->timestamp = now; -} - -static inline void update_cgrp_time_from_cpuctx(struct perf_cpu_context *cpuctx) -{ - struct perf_cgroup *cgrp_out = cpuctx->cgrp; - if (cgrp_out) - __update_cgrp_time(cgrp_out); -} - -static inline void update_cgrp_time_from_event(struct perf_event *event) -{ - struct perf_cgroup *cgrp; - - /* - * ensure we access cgroup data only when needed and - * when we know the cgroup is pinned (css_get) - */ - if (!is_cgroup_event(event)) - return; - - cgrp = perf_cgroup_from_task(current); - /* - * Do not update time when cgroup is not active - */ - if (cgrp == event->cgrp) - __update_cgrp_time(event->cgrp); -} - -static inline void -perf_cgroup_set_timestamp(struct task_struct *task, - struct perf_event_context *ctx) -{ - struct perf_cgroup *cgrp; - struct perf_cgroup_info *info; - - /* - * ctx->lock held by caller - * ensure we do not access cgroup data - * unless we have the cgroup pinned (css_get) - */ - if (!task || !ctx->nr_cgroups) - return; - - cgrp = perf_cgroup_from_task(task); - info = this_cpu_ptr(cgrp->info); - info->timestamp = ctx->timestamp; -} - -#define PERF_CGROUP_SWOUT 0x1 /* cgroup switch out every event */ -#define PERF_CGROUP_SWIN 0x2 /* cgroup switch in events based on task */ - -/* - * reschedule events based on the cgroup constraint of task. - * - * mode SWOUT : schedule out everything - * mode SWIN : schedule in based on cgroup for next - */ -void perf_cgroup_switch(struct task_struct *task, int mode) -{ - struct perf_cpu_context *cpuctx; - struct pmu *pmu; - unsigned long flags; - - /* - * disable interrupts to avoid geting nr_cgroup - * changes via __perf_event_disable(). Also - * avoids preemption. - */ - local_irq_save(flags); - - /* - * we reschedule only in the presence of cgroup - * constrained events. - */ - rcu_read_lock(); - - list_for_each_entry_rcu(pmu, &pmus, entry) { - - cpuctx = this_cpu_ptr(pmu->pmu_cpu_context); - - perf_pmu_disable(cpuctx->ctx.pmu); - - /* - * perf_cgroup_events says at least one - * context on this CPU has cgroup events. - * - * ctx->nr_cgroups reports the number of cgroup - * events for a context. - */ - if (cpuctx->ctx.nr_cgroups > 0) { - - if (mode & PERF_CGROUP_SWOUT) { - cpu_ctx_sched_out(cpuctx, EVENT_ALL); - /* - * must not be done before ctxswout due - * to event_filter_match() in event_sched_out() - */ - cpuctx->cgrp = NULL; - } - - if (mode & PERF_CGROUP_SWIN) { - WARN_ON_ONCE(cpuctx->cgrp); - /* set cgrp before ctxsw in to - * allow event_filter_match() to not - * have to pass task around - */ - cpuctx->cgrp = perf_cgroup_from_task(task); - cpu_ctx_sched_in(cpuctx, EVENT_ALL, task); - } - } - - perf_pmu_enable(cpuctx->ctx.pmu); - } - - rcu_read_unlock(); - - local_irq_restore(flags); -} - -static inline void perf_cgroup_sched_out(struct task_struct *task) -{ - perf_cgroup_switch(task, PERF_CGROUP_SWOUT); -} - -static inline void perf_cgroup_sched_in(struct task_struct *task) -{ - perf_cgroup_switch(task, PERF_CGROUP_SWIN); -} - -static inline int perf_cgroup_connect(int fd, struct perf_event *event, - struct perf_event_attr *attr, - struct perf_event *group_leader) -{ - struct perf_cgroup *cgrp; - struct cgroup_subsys_state *css; - struct file *file; - int ret = 0, fput_needed; - - file = fget_light(fd, &fput_needed); - if (!file) - return -EBADF; - - css = cgroup_css_from_dir(file, perf_subsys_id); - if (IS_ERR(css)) { - ret = PTR_ERR(css); - goto out; - } - - cgrp = container_of(css, struct perf_cgroup, css); - event->cgrp = cgrp; - - /* must be done before we fput() the file */ - perf_get_cgroup(event); - - /* - * all events in a group must monitor - * the same cgroup because a task belongs - * to only one perf cgroup at a time - */ - if (group_leader && group_leader->cgrp != cgrp) { - perf_detach_cgroup(event); - ret = -EINVAL; - } -out: - fput_light(file, fput_needed); - return ret; -} - -static inline void -perf_cgroup_set_shadow_time(struct perf_event *event, u64 now) -{ - struct perf_cgroup_info *t; - t = per_cpu_ptr(event->cgrp->info, event->cpu); - event->shadow_ctx_time = now - t->timestamp; -} - -static inline void -perf_cgroup_defer_enabled(struct perf_event *event) -{ - /* - * when the current task's perf cgroup does not match - * the event's, we need to remember to call the - * perf_mark_enable() function the first time a task with - * a matching perf cgroup is scheduled in. - */ - if (is_cgroup_event(event) && !perf_cgroup_match(event)) - event->cgrp_defer_enabled = 1; -} - -static inline void -perf_cgroup_mark_enabled(struct perf_event *event, - struct perf_event_context *ctx) -{ - struct perf_event *sub; - u64 tstamp = perf_event_time(event); - - if (!event->cgrp_defer_enabled) - return; - - event->cgrp_defer_enabled = 0; - - event->tstamp_enabled = tstamp - event->total_time_enabled; - list_for_each_entry(sub, &event->sibling_list, group_entry) { - if (sub->state >= PERF_EVENT_STATE_INACTIVE) { - sub->tstamp_enabled = tstamp - sub->total_time_enabled; - sub->cgrp_defer_enabled = 0; - } - } -} -#else /* !CONFIG_CGROUP_PERF */ - -static inline bool -perf_cgroup_match(struct perf_event *event) -{ - return true; -} - -static inline void perf_detach_cgroup(struct perf_event *event) -{} - -static inline int is_cgroup_event(struct perf_event *event) -{ - return 0; -} - -static inline u64 perf_cgroup_event_cgrp_time(struct perf_event *event) -{ - return 0; -} - -static inline void update_cgrp_time_from_event(struct perf_event *event) -{ -} - -static inline void update_cgrp_time_from_cpuctx(struct perf_cpu_context *cpuctx) -{ -} - -static inline void perf_cgroup_sched_out(struct task_struct *task) -{ -} - -static inline void perf_cgroup_sched_in(struct task_struct *task) -{ -} - -static inline int perf_cgroup_connect(pid_t pid, struct perf_event *event, - struct perf_event_attr *attr, - struct perf_event *group_leader) -{ - return -EINVAL; -} - -static inline void -perf_cgroup_set_timestamp(struct task_struct *task, - struct perf_event_context *ctx) -{ -} - -void -perf_cgroup_switch(struct task_struct *task, struct task_struct *next) -{ -} - -static inline void -perf_cgroup_set_shadow_time(struct perf_event *event, u64 now) -{ -} - -static inline u64 perf_cgroup_event_time(struct perf_event *event) -{ - return 0; -} - -static inline void -perf_cgroup_defer_enabled(struct perf_event *event) -{ -} - -static inline void -perf_cgroup_mark_enabled(struct perf_event *event, - struct perf_event_context *ctx) -{ -} -#endif - -void perf_pmu_disable(struct pmu *pmu) -{ - int *count = this_cpu_ptr(pmu->pmu_disable_count); - if (!(*count)++) - pmu->pmu_disable(pmu); -} - -void perf_pmu_enable(struct pmu *pmu) -{ - int *count = this_cpu_ptr(pmu->pmu_disable_count); - if (!--(*count)) - pmu->pmu_enable(pmu); -} - -static DEFINE_PER_CPU(struct list_head, rotation_list); - -/* - * perf_pmu_rotate_start() and perf_rotate_context() are fully serialized - * because they're strictly cpu affine and rotate_start is called with IRQs - * disabled, while rotate_context is called from IRQ context. - */ -static void perf_pmu_rotate_start(struct pmu *pmu) -{ - struct perf_cpu_context *cpuctx = this_cpu_ptr(pmu->pmu_cpu_context); - struct list_head *head = &__get_cpu_var(rotation_list); - - WARN_ON(!irqs_disabled()); - - if (list_empty(&cpuctx->rotation_list)) - list_add(&cpuctx->rotation_list, head); -} - -static void get_ctx(struct perf_event_context *ctx) -{ - WARN_ON(!atomic_inc_not_zero(&ctx->refcount)); -} - -static void free_ctx(struct rcu_head *head) -{ - struct perf_event_context *ctx; - - ctx = container_of(head, struct perf_event_context, rcu_head); - kfree(ctx); -} - -static void put_ctx(struct perf_event_context *ctx) -{ - if (atomic_dec_and_test(&ctx->refcount)) { - if (ctx->parent_ctx) - put_ctx(ctx->parent_ctx); - if (ctx->task) - put_task_struct(ctx->task); - call_rcu(&ctx->rcu_head, free_ctx); - } -} - -static void unclone_ctx(struct perf_event_context *ctx) -{ - if (ctx->parent_ctx) { - put_ctx(ctx->parent_ctx); - ctx->parent_ctx = NULL; - } -} - -static u32 perf_event_pid(struct perf_event *event, struct task_struct *p) -{ - /* - * only top level events have the pid namespace they were created in - */ - if (event->parent) - event = event->parent; - - return task_tgid_nr_ns(p, event->ns); -} - -static u32 perf_event_tid(struct perf_event *event, struct task_struct *p) -{ - /* - * only top level events have the pid namespace they were created in - */ - if (event->parent) - event = event->parent; - - return task_pid_nr_ns(p, event->ns); -} - -/* - * If we inherit events we want to return the parent event id - * to userspace. - */ -static u64 primary_event_id(struct perf_event *event) -{ - u64 id = event->id; - - if (event->parent) - id = event->parent->id; - - return id; -} - -/* - * Get the perf_event_context for a task and lock it. - * This has to cope with with the fact that until it is locked, - * the context could get moved to another task. - */ -static struct perf_event_context * -perf_lock_task_context(struct task_struct *task, int ctxn, unsigned long *flags) -{ - struct perf_event_context *ctx; - - rcu_read_lock(); -retry: - ctx = rcu_dereference(task->perf_event_ctxp[ctxn]); - if (ctx) { - /* - * If this context is a clone of another, it might - * get swapped for another underneath us by - * perf_event_task_sched_out, though the - * rcu_read_lock() protects us from any context - * getting freed. Lock the context and check if it - * got swapped before we could get the lock, and retry - * if so. If we locked the right context, then it - * can't get swapped on us any more. - */ - raw_spin_lock_irqsave(&ctx->lock, *flags); - if (ctx != rcu_dereference(task->perf_event_ctxp[ctxn])) { - raw_spin_unlock_irqrestore(&ctx->lock, *flags); - goto retry; - } - - if (!atomic_inc_not_zero(&ctx->refcount)) { - raw_spin_unlock_irqrestore(&ctx->lock, *flags); - ctx = NULL; - } - } - rcu_read_unlock(); - return ctx; -} - -/* - * Get the context for a task and increment its pin_count so it - * can't get swapped to another task. This also increments its - * reference count so that the context can't get freed. - */ -static struct perf_event_context * -perf_pin_task_context(struct task_struct *task, int ctxn) -{ - struct perf_event_context *ctx; - unsigned long flags; - - ctx = perf_lock_task_context(task, ctxn, &flags); - if (ctx) { - ++ctx->pin_count; - raw_spin_unlock_irqrestore(&ctx->lock, flags); - } - return ctx; -} - -static void perf_unpin_context(struct perf_event_context *ctx) -{ - unsigned long flags; - - raw_spin_lock_irqsave(&ctx->lock, flags); - --ctx->pin_count; - raw_spin_unlock_irqrestore(&ctx->lock, flags); -} - -/* - * Update the record of the current time in a context. - */ -static void update_context_time(struct perf_event_context *ctx) -{ - u64 now = perf_clock(); - - ctx->time += now - ctx->timestamp; - ctx->timestamp = now; -} - -static u64 perf_event_time(struct perf_event *event) -{ - struct perf_event_context *ctx = event->ctx; - - if (is_cgroup_event(event)) - return perf_cgroup_event_time(event); - - return ctx ? ctx->time : 0; -} - -/* - * Update the total_time_enabled and total_time_running fields for a event. - */ -static void update_event_times(struct perf_event *event) -{ - struct perf_event_context *ctx = event->ctx; - u64 run_end; - - if (event->state < PERF_EVENT_STATE_INACTIVE || - event->group_leader->state < PERF_EVENT_STATE_INACTIVE) - return; - /* - * in cgroup mode, time_enabled represents - * the time the event was enabled AND active - * tasks were in the monitored cgroup. This is - * independent of the activity of the context as - * there may be a mix of cgroup and non-cgroup events. - * - * That is why we treat cgroup events differently - * here. - */ - if (is_cgroup_event(event)) - run_end = perf_event_time(event); - else if (ctx->is_active) - run_end = ctx->time; - else - run_end = event->tstamp_stopped; - - event->total_time_enabled = run_end - event->tstamp_enabled; - - if (event->state == PERF_EVENT_STATE_INACTIVE) - run_end = event->tstamp_stopped; - else - run_end = perf_event_time(event); - - event->total_time_running = run_end - event->tstamp_running; - -} - -/* - * Update total_time_enabled and total_time_running for all events in a group. - */ -static void update_group_times(struct perf_event *leader) -{ - struct perf_event *event; - - update_event_times(leader); - list_for_each_entry(event, &leader->sibling_list, group_entry) - update_event_times(event); -} - -static struct list_head * -ctx_group_list(struct perf_event *event, struct perf_event_context *ctx) -{ - if (event->attr.pinned) - return &ctx->pinned_groups; - else - return &ctx->flexible_groups; -} - -/* - * Add a event from the lists for its context. - * Must be called with ctx->mutex and ctx->lock held. - */ -static void -list_add_event(struct perf_event *event, struct perf_event_context *ctx) -{ - WARN_ON_ONCE(event->attach_state & PERF_ATTACH_CONTEXT); - event->attach_state |= PERF_ATTACH_CONTEXT; - - /* - * If we're a stand alone event or group leader, we go to the context - * list, group events are kept attached to the group so that - * perf_group_detach can, at all times, locate all siblings. - */ - if (event->group_leader == event) { - struct list_head *list; - - if (is_software_event(event)) - event->group_flags |= PERF_GROUP_SOFTWARE; - - list = ctx_group_list(event, ctx); - list_add_tail(&event->group_entry, list); - } - - if (is_cgroup_event(event)) - ctx->nr_cgroups++; - - list_add_rcu(&event->event_entry, &ctx->event_list); - if (!ctx->nr_events) - perf_pmu_rotate_start(ctx->pmu); - ctx->nr_events++; - if (event->attr.inherit_stat) - ctx->nr_stat++; -} - -/* - * Called at perf_event creation and when events are attached/detached from a - * group. - */ -static void perf_event__read_size(struct perf_event *event) -{ - int entry = sizeof(u64); /* value */ - int size = 0; - int nr = 1; - - if (event->attr.read_format & PERF_FORMAT_TOTAL_TIME_ENABLED) - size += sizeof(u64); - - if (event->attr.read_format & PERF_FORMAT_TOTAL_TIME_RUNNING) - size += sizeof(u64); - - if (event->attr.read_format & PERF_FORMAT_ID) - entry += sizeof(u64); - - if (event->attr.read_format & PERF_FORMAT_GROUP) { - nr += event->group_leader->nr_siblings; - size += sizeof(u64); - } - - size += entry * nr; - event->read_size = size; -} - -static void perf_event__header_size(struct perf_event *event) -{ - struct perf_sample_data *data; - u64 sample_type = event->attr.sample_type; - u16 size = 0; - - perf_event__read_size(event); - - if (sample_type & PERF_SAMPLE_IP) - size += sizeof(data->ip); - - if (sample_type & PERF_SAMPLE_ADDR) - size += sizeof(data->addr); - - if (sample_type & PERF_SAMPLE_PERIOD) - size += sizeof(data->period); - - if (sample_type & PERF_SAMPLE_READ) - size += event->read_size; - - event->header_size = size; -} - -static void perf_event__id_header_size(struct perf_event *event) -{ - struct perf_sample_data *data; - u64 sample_type = event->attr.sample_type; - u16 size = 0; - - if (sample_type & PERF_SAMPLE_TID) - size += sizeof(data->tid_entry); - - if (sample_type & PERF_SAMPLE_TIME) - size += sizeof(data->time); - - if (sample_type & PERF_SAMPLE_ID) - size += sizeof(data->id); - - if (sample_type & PERF_SAMPLE_STREAM_ID) - size += sizeof(data->stream_id); - - if (sample_type & PERF_SAMPLE_CPU) - size += sizeof(data->cpu_entry); - - event->id_header_size = size; -} - -static void perf_group_attach(struct perf_event *event) -{ - struct perf_event *group_leader = event->group_leader, *pos; - - /* - * We can have double attach due to group movement in perf_event_open. - */ - if (event->attach_state & PERF_ATTACH_GROUP) - return; - - event->attach_state |= PERF_ATTACH_GROUP; - - if (group_leader == event) - return; - - if (group_leader->group_flags & PERF_GROUP_SOFTWARE && - !is_software_event(event)) - group_leader->group_flags &= ~PERF_GROUP_SOFTWARE; - - list_add_tail(&event->group_entry, &group_leader->sibling_list); - group_leader->nr_siblings++; - - perf_event__header_size(group_leader); - - list_for_each_entry(pos, &group_leader->sibling_list, group_entry) - perf_event__header_size(pos); -} - -/* - * Remove a event from the lists for its context. - * Must be called with ctx->mutex and ctx->lock held. - */ -static void -list_del_event(struct perf_event *event, struct perf_event_context *ctx) -{ - struct perf_cpu_context *cpuctx; - /* - * We can have double detach due to exit/hot-unplug + close. - */ - if (!(event->attach_state & PERF_ATTACH_CONTEXT)) - return; - - event->attach_state &= ~PERF_ATTACH_CONTEXT; - - if (is_cgroup_event(event)) { - ctx->nr_cgroups--; - cpuctx = __get_cpu_context(ctx); - /* - * if there are no more cgroup events - * then cler cgrp to avoid stale pointer - * in update_cgrp_time_from_cpuctx() - */ - if (!ctx->nr_cgroups) - cpuctx->cgrp = NULL; - } - - ctx->nr_events--; - if (event->attr.inherit_stat) - ctx->nr_stat--; - - list_del_rcu(&event->event_entry); - - if (event->group_leader == event) - list_del_init(&event->group_entry); - - update_group_times(event); - - /* - * If event was in error state, then keep it - * that way, otherwise bogus counts will be - * returned on read(). The only way to get out - * of error state is by explicit re-enabling - * of the event - */ - if (event->state > PERF_EVENT_STATE_OFF) - event->state = PERF_EVENT_STATE_OFF; -} - -static void perf_group_detach(struct perf_event *event) -{ - struct perf_event *sibling, *tmp; - struct list_head *list = NULL; - - /* - * We can have double detach due to exit/hot-unplug + close. - */ - if (!(event->attach_state & PERF_ATTACH_GROUP)) - return; - - event->attach_state &= ~PERF_ATTACH_GROUP; - - /* - * If this is a sibling, remove it from its group. - */ - if (event->group_leader != event) { - list_del_init(&event->group_entry); - event->group_leader->nr_siblings--; - goto out; - } - - if (!list_empty(&event->group_entry)) - list = &event->group_entry; - - /* - * If this was a group event with sibling events then - * upgrade the siblings to singleton events by adding them - * to whatever list we are on. - */ - list_for_each_entry_safe(sibling, tmp, &event->sibling_list, group_entry) { - if (list) - list_move_tail(&sibling->group_entry, list); - sibling->group_leader = sibling; - - /* Inherit group flags from the previous leader */ - sibling->group_flags = event->group_flags; - } - -out: - perf_event__header_size(event->group_leader); - - list_for_each_entry(tmp, &event->group_leader->sibling_list, group_entry) - perf_event__header_size(tmp); -} - -static inline int -event_filter_match(struct perf_event *event) -{ - return (event->cpu == -1 || event->cpu == smp_processor_id()) - && perf_cgroup_match(event); -} - -static void -event_sched_out(struct perf_event *event, - struct perf_cpu_context *cpuctx, - struct perf_event_context *ctx) -{ - u64 tstamp = perf_event_time(event); - u64 delta; - /* - * An event which could not be activated because of - * filter mismatch still needs to have its timings - * maintained, otherwise bogus information is return - * via read() for time_enabled, time_running: - */ - if (event->state == PERF_EVENT_STATE_INACTIVE - && !event_filter_match(event)) { - delta = tstamp - event->tstamp_stopped; - event->tstamp_running += delta; - event->tstamp_stopped = tstamp; - } - - if (event->state != PERF_EVENT_STATE_ACTIVE) - return; - - event->state = PERF_EVENT_STATE_INACTIVE; - if (event->pending_disable) { - event->pending_disable = 0; - event->state = PERF_EVENT_STATE_OFF; - } - event->tstamp_stopped = tstamp; - event->pmu->del(event, 0); - event->oncpu = -1; - - if (!is_software_event(event)) - cpuctx->active_oncpu--; - ctx->nr_active--; - if (event->attr.exclusive || !cpuctx->active_oncpu) - cpuctx->exclusive = 0; -} - -static void -group_sched_out(struct perf_event *group_event, - struct perf_cpu_context *cpuctx, - struct perf_event_context *ctx) -{ - struct perf_event *event; - int state = group_event->state; - - event_sched_out(group_event, cpuctx, ctx); - - /* - * Schedule out siblings (if any): - */ - list_for_each_entry(event, &group_event->sibling_list, group_entry) - event_sched_out(event, cpuctx, ctx); - - if (state == PERF_EVENT_STATE_ACTIVE && group_event->attr.exclusive) - cpuctx->exclusive = 0; -} - -/* - * Cross CPU call to remove a performance event - * - * We disable the event on the hardware level first. After that we - * remove it from the context list. - */ -static int __perf_remove_from_context(void *info) -{ - struct perf_event *event = info; - struct perf_event_context *ctx = event->ctx; - struct perf_cpu_context *cpuctx = __get_cpu_context(ctx); - - raw_spin_lock(&ctx->lock); - event_sched_out(event, cpuctx, ctx); - list_del_event(event, ctx); - raw_spin_unlock(&ctx->lock); - - return 0; -} - - -/* - * Remove the event from a task's (or a CPU's) list of events. - * - * CPU events are removed with a smp call. For task events we only - * call when the task is on a CPU. - * - * If event->ctx is a cloned context, callers must make sure that - * every task struct that event->ctx->task could possibly point to - * remains valid. This is OK when called from perf_release since - * that only calls us on the top-level context, which can't be a clone. - * When called from perf_event_exit_task, it's OK because the - * context has been detached from its task. - */ -static void perf_remove_from_context(struct perf_event *event) -{ - struct perf_event_context *ctx = event->ctx; - struct task_struct *task = ctx->task; - - lockdep_assert_held(&ctx->mutex); - - if (!task) { - /* - * Per cpu events are removed via an smp call and - * the removal is always successful. - */ - cpu_function_call(event->cpu, __perf_remove_from_context, event); - return; - } - -retry: - if (!task_function_call(task, __perf_remove_from_context, event)) - return; - - raw_spin_lock_irq(&ctx->lock); - /* - * If we failed to find a running task, but find the context active now - * that we've acquired the ctx->lock, retry. - */ - if (ctx->is_active) { - raw_spin_unlock_irq(&ctx->lock); - goto retry; - } - - /* - * Since the task isn't running, its safe to remove the event, us - * holding the ctx->lock ensures the task won't get scheduled in. - */ - list_del_event(event, ctx); - raw_spin_unlock_irq(&ctx->lock); -} - -/* - * Cross CPU call to disable a performance event - */ -static int __perf_event_disable(void *info) -{ - struct perf_event *event = info; - struct perf_event_context *ctx = event->ctx; - struct perf_cpu_context *cpuctx = __get_cpu_context(ctx); - - /* - * If this is a per-task event, need to check whether this - * event's task is the current task on this cpu. - * - * Can trigger due to concurrent perf_event_context_sched_out() - * flipping contexts around. - */ - if (ctx->task && cpuctx->task_ctx != ctx) - return -EINVAL; - - raw_spin_lock(&ctx->lock); - - /* - * If the event is on, turn it off. - * If it is in error state, leave it in error state. - */ - if (event->state >= PERF_EVENT_STATE_INACTIVE) { - update_context_time(ctx); - update_cgrp_time_from_event(event); - update_group_times(event); - if (event == event->group_leader) - group_sched_out(event, cpuctx, ctx); - else - event_sched_out(event, cpuctx, ctx); - event->state = PERF_EVENT_STATE_OFF; - } - - raw_spin_unlock(&ctx->lock); - - return 0; -} - -/* - * Disable a event. - * - * If event->ctx is a cloned context, callers must make sure that - * every task struct that event->ctx->task could possibly point to - * remains valid. This condition is satisifed when called through - * perf_event_for_each_child or perf_event_for_each because they - * hold the top-level event's child_mutex, so any descendant that - * goes to exit will block in sync_child_event. - * When called from perf_pending_event it's OK because event->ctx - * is the current context on this CPU and preemption is disabled, - * hence we can't get into perf_event_task_sched_out for this context. - */ -void perf_event_disable(struct perf_event *event) -{ - struct perf_event_context *ctx = event->ctx; - struct task_struct *task = ctx->task; - - if (!task) { - /* - * Disable the event on the cpu that it's on - */ - cpu_function_call(event->cpu, __perf_event_disable, event); - return; - } - -retry: - if (!task_function_call(task, __perf_event_disable, event)) - return; - - raw_spin_lock_irq(&ctx->lock); - /* - * If the event is still active, we need to retry the cross-call. - */ - if (event->state == PERF_EVENT_STATE_ACTIVE) { - raw_spin_unlock_irq(&ctx->lock); - /* - * Reload the task pointer, it might have been changed by - * a concurrent perf_event_context_sched_out(). - */ - task = ctx->task; - goto retry; - } - - /* - * Since we have the lock this context can't be scheduled - * in, so we can change the state safely. - */ - if (event->state == PERF_EVENT_STATE_INACTIVE) { - update_group_times(event); - event->state = PERF_EVENT_STATE_OFF; - } - raw_spin_unlock_irq(&ctx->lock); -} - -static void perf_set_shadow_time(struct perf_event *event, - struct perf_event_context *ctx, - u64 tstamp) -{ - /* - * use the correct time source for the time snapshot - * - * We could get by without this by leveraging the - * fact that to get to this function, the caller - * has most likely already called update_context_time() - * and update_cgrp_time_xx() and thus both timestamp - * are identical (or very close). Given that tstamp is, - * already adjusted for cgroup, we could say that: - * tstamp - ctx->timestamp - * is equivalent to - * tstamp - cgrp->timestamp. - * - * Then, in perf_output_read(), the calculation would - * work with no changes because: - * - event is guaranteed scheduled in - * - no scheduled out in between - * - thus the timestamp would be the same - * - * But this is a bit hairy. - * - * So instead, we have an explicit cgroup call to remain - * within the time time source all along. We believe it - * is cleaner and simpler to understand. - */ - if (is_cgroup_event(event)) - perf_cgroup_set_shadow_time(event, tstamp); - else - event->shadow_ctx_time = tstamp - ctx->timestamp; -} - -#define MAX_INTERRUPTS (~0ULL) - -static void perf_log_throttle(struct perf_event *event, int enable); - -static int -event_sched_in(struct perf_event *event, - struct perf_cpu_context *cpuctx, - struct perf_event_context *ctx) -{ - u64 tstamp = perf_event_time(event); - - if (event->state <= PERF_EVENT_STATE_OFF) - return 0; - - event->state = PERF_EVENT_STATE_ACTIVE; - event->oncpu = smp_processor_id(); - - /* - * Unthrottle events, since we scheduled we might have missed several - * ticks already, also for a heavily scheduling task there is little - * guarantee it'll get a tick in a timely manner. - */ - if (unlikely(event->hw.interrupts == MAX_INTERRUPTS)) { - perf_log_throttle(event, 1); - event->hw.interrupts = 0; - } - - /* - * The new state must be visible before we turn it on in the hardware: - */ - smp_wmb(); - - if (event->pmu->add(event, PERF_EF_START)) { - event->state = PERF_EVENT_STATE_INACTIVE; - event->oncpu = -1; - return -EAGAIN; - } - - event->tstamp_running += tstamp - event->tstamp_stopped; - - perf_set_shadow_time(event, ctx, tstamp); - - if (!is_software_event(event)) - cpuctx->active_oncpu++; - ctx->nr_active++; - - if (event->attr.exclusive) - cpuctx->exclusive = 1; - - return 0; -} - -static int -group_sched_in(struct perf_event *group_event, - struct perf_cpu_context *cpuctx, - struct perf_event_context *ctx) -{ - struct perf_event *event, *partial_group = NULL; - struct pmu *pmu = group_event->pmu; - u64 now = ctx->time; - bool simulate = false; - - if (group_event->state == PERF_EVENT_STATE_OFF) - return 0; - - pmu->start_txn(pmu); - - if (event_sched_in(group_event, cpuctx, ctx)) { - pmu->cancel_txn(pmu); - return -EAGAIN; - } - - /* - * Schedule in siblings as one group (if any): - */ - list_for_each_entry(event, &group_event->sibling_list, group_entry) { - if (event_sched_in(event, cpuctx, ctx)) { - partial_group = event; - goto group_error; - } - } - - if (!pmu->commit_txn(pmu)) - return 0; - -group_error: - /* - * Groups can be scheduled in as one unit only, so undo any - * partial group before returning: - * The events up to the failed event are scheduled out normally, - * tstamp_stopped will be updated. - * - * The failed events and the remaining siblings need to have - * their timings updated as if they had gone thru event_sched_in() - * and event_sched_out(). This is required to get consistent timings - * across the group. This also takes care of the case where the group - * could never be scheduled by ensuring tstamp_stopped is set to mark - * the time the event was actually stopped, such that time delta - * calculation in update_event_times() is correct. - */ - list_for_each_entry(event, &group_event->sibling_list, group_entry) { - if (event == partial_group) - simulate = true; - - if (simulate) { - event->tstamp_running += now - event->tstamp_stopped; - event->tstamp_stopped = now; - } else { - event_sched_out(event, cpuctx, ctx); - } - } - event_sched_out(group_event, cpuctx, ctx); - - pmu->cancel_txn(pmu); - - return -EAGAIN; -} - -/* - * Work out whether we can put this event group on the CPU now. - */ -static int group_can_go_on(struct perf_event *event, - struct perf_cpu_context *cpuctx, - int can_add_hw) -{ - /* - * Groups consisting entirely of software events can always go on. - */ - if (event->group_flags & PERF_GROUP_SOFTWARE) - return 1; - /* - * If an exclusive group is already on, no other hardware - * events can go on. - */ - if (cpuctx->exclusive) - return 0; - /* - * If this group is exclusive and there are already - * events on the CPU, it can't go on. - */ - if (event->attr.exclusive && cpuctx->active_oncpu) - return 0; - /* - * Otherwise, try to add it if all previous groups were able - * to go on. - */ - return can_add_hw; -} - -static void add_event_to_ctx(struct perf_event *event, - struct perf_event_context *ctx) -{ - u64 tstamp = perf_event_time(event); - - list_add_event(event, ctx); - perf_group_attach(event); - event->tstamp_enabled = tstamp; - event->tstamp_running = tstamp; - event->tstamp_stopped = tstamp; -} - -static void perf_event_context_sched_in(struct perf_event_context *ctx, - struct task_struct *tsk); - -/* - * Cross CPU call to install and enable a performance event - * - * Must be called with ctx->mutex held - */ -static int __perf_install_in_context(void *info) -{ - struct perf_event *event = info; - struct perf_event_context *ctx = event->ctx; - struct perf_event *leader = event->group_leader; - struct perf_cpu_context *cpuctx = __get_cpu_context(ctx); - int err; - - /* - * In case we're installing a new context to an already running task, - * could also happen before perf_event_task_sched_in() on architectures - * which do context switches with IRQs enabled. - */ - if (ctx->task && !cpuctx->task_ctx) - perf_event_context_sched_in(ctx, ctx->task); - - raw_spin_lock(&ctx->lock); - ctx->is_active = 1; - update_context_time(ctx); - /* - * update cgrp time only if current cgrp - * matches event->cgrp. Must be done before - * calling add_event_to_ctx() - */ - update_cgrp_time_from_event(event); - - add_event_to_ctx(event, ctx); - - if (!event_filter_match(event)) - goto unlock; - - /* - * Don't put the event on if it is disabled or if - * it is in a group and the group isn't on. - */ - if (event->state != PERF_EVENT_STATE_INACTIVE || - (leader != event && leader->state != PERF_EVENT_STATE_ACTIVE)) - goto unlock; - - /* - * An exclusive event can't go on if there are already active - * hardware events, and no hardware event can go on if there - * is already an exclusive event on. - */ - if (!group_can_go_on(event, cpuctx, 1)) - err = -EEXIST; - else - err = event_sched_in(event, cpuctx, ctx); - - if (err) { - /* - * This event couldn't go on. If it is in a group - * then we have to pull the whole group off. - * If the event group is pinned then put it in error state. - */ - if (leader != event) - group_sched_out(leader, cpuctx, ctx); - if (leader->attr.pinned) { - update_group_times(leader); - leader->state = PERF_EVENT_STATE_ERROR; - } - } - -unlock: - raw_spin_unlock(&ctx->lock); - - return 0; -} - -/* - * Attach a performance event to a context - * - * First we add the event to the list with the hardware enable bit - * in event->hw_config cleared. - * - * If the event is attached to a task which is on a CPU we use a smp - * call to enable it in the task context. The task might have been - * scheduled away, but we check this in the smp call again. - */ -static void -perf_install_in_context(struct perf_event_context *ctx, - struct perf_event *event, - int cpu) -{ - struct task_struct *task = ctx->task; - - lockdep_assert_held(&ctx->mutex); - - event->ctx = ctx; - - if (!task) { - /* - * Per cpu events are installed via an smp call and - * the install is always successful. - */ - cpu_function_call(cpu, __perf_install_in_context, event); - return; - } - -retry: - if (!task_function_call(task, __perf_install_in_context, event)) - return; - - raw_spin_lock_irq(&ctx->lock); - /* - * If we failed to find a running task, but find the context active now - * that we've acquired the ctx->lock, retry. - */ - if (ctx->is_active) { - raw_spin_unlock_irq(&ctx->lock); - goto retry; - } - - /* - * Since the task isn't running, its safe to add the event, us holding - * the ctx->lock ensures the task won't get scheduled in. - */ - add_event_to_ctx(event, ctx); - raw_spin_unlock_irq(&ctx->lock); -} - -/* - * Put a event into inactive state and update time fields. - * Enabling the leader of a group effectively enables all - * the group members that aren't explicitly disabled, so we - * have to update their ->tstamp_enabled also. - * Note: this works for group members as well as group leaders - * since the non-leader members' sibling_lists will be empty. - */ -static void __perf_event_mark_enabled(struct perf_event *event, - struct perf_event_context *ctx) -{ - struct perf_event *sub; - u64 tstamp = perf_event_time(event); - - event->state = PERF_EVENT_STATE_INACTIVE; - event->tstamp_enabled = tstamp - event->total_time_enabled; - list_for_each_entry(sub, &event->sibling_list, group_entry) { - if (sub->state >= PERF_EVENT_STATE_INACTIVE) - sub->tstamp_enabled = tstamp - sub->total_time_enabled; - } -} - -/* - * Cross CPU call to enable a performance event - */ -static int __perf_event_enable(void *info) -{ - struct perf_event *event = info; - struct perf_event_context *ctx = event->ctx; - struct perf_event *leader = event->group_leader; - struct perf_cpu_context *cpuctx = __get_cpu_context(ctx); - int err; - - if (WARN_ON_ONCE(!ctx->is_active)) - return -EINVAL; - - raw_spin_lock(&ctx->lock); - update_context_time(ctx); - - if (event->state >= PERF_EVENT_STATE_INACTIVE) - goto unlock; - - /* - * set current task's cgroup time reference point - */ - perf_cgroup_set_timestamp(current, ctx); - - __perf_event_mark_enabled(event, ctx); - - if (!event_filter_match(event)) { - if (is_cgroup_event(event)) - perf_cgroup_defer_enabled(event); - goto unlock; - } - - /* - * If the event is in a group and isn't the group leader, - * then don't put it on unless the group is on. - */ - if (leader != event && leader->state != PERF_EVENT_STATE_ACTIVE) - goto unlock; - - if (!group_can_go_on(event, cpuctx, 1)) { - err = -EEXIST; - } else { - if (event == leader) - err = group_sched_in(event, cpuctx, ctx); - else - err = event_sched_in(event, cpuctx, ctx); - } - - if (err) { - /* - * If this event can't go on and it's part of a - * group, then the whole group has to come off. - */ - if (leader != event) - group_sched_out(leader, cpuctx, ctx); - if (leader->attr.pinned) { - update_group_times(leader); - leader->state = PERF_EVENT_STATE_ERROR; - } - } - -unlock: - raw_spin_unlock(&ctx->lock); - - return 0; -} - -/* - * Enable a event. - * - * If event->ctx is a cloned context, callers must make sure that - * every task struct that event->ctx->task could possibly point to - * remains valid. This condition is satisfied when called through - * perf_event_for_each_child or perf_event_for_each as described - * for perf_event_disable. - */ -void perf_event_enable(struct perf_event *event) -{ - struct perf_event_context *ctx = event->ctx; - struct task_struct *task = ctx->task; - - if (!task) { - /* - * Enable the event on the cpu that it's on - */ - cpu_function_call(event->cpu, __perf_event_enable, event); - return; - } - - raw_spin_lock_irq(&ctx->lock); - if (event->state >= PERF_EVENT_STATE_INACTIVE) - goto out; - - /* - * If the event is in error state, clear that first. - * That way, if we see the event in error state below, we - * know that it has gone back into error state, as distinct - * from the task having been scheduled away before the - * cross-call arrived. - */ - if (event->state == PERF_EVENT_STATE_ERROR) - event->state = PERF_EVENT_STATE_OFF; - -retry: - if (!ctx->is_active) { - __perf_event_mark_enabled(event, ctx); - goto out; - } - - raw_spin_unlock_irq(&ctx->lock); - - if (!task_function_call(task, __perf_event_enable, event)) - return; - - raw_spin_lock_irq(&ctx->lock); - - /* - * If the context is active and the event is still off, - * we need to retry the cross-call. - */ - if (ctx->is_active && event->state == PERF_EVENT_STATE_OFF) { - /* - * task could have been flipped by a concurrent - * perf_event_context_sched_out() - */ - task = ctx->task; - goto retry; - } - -out: - raw_spin_unlock_irq(&ctx->lock); -} - -static int perf_event_refresh(struct perf_event *event, int refresh) -{ - /* - * not supported on inherited events - */ - if (event->attr.inherit || !is_sampling_event(event)) - return -EINVAL; - - atomic_add(refresh, &event->event_limit); - perf_event_enable(event); - - return 0; -} - -static void ctx_sched_out(struct perf_event_context *ctx, - struct perf_cpu_context *cpuctx, - enum event_type_t event_type) -{ - struct perf_event *event; - - raw_spin_lock(&ctx->lock); - perf_pmu_disable(ctx->pmu); - ctx->is_active = 0; - if (likely(!ctx->nr_events)) - goto out; - update_context_time(ctx); - update_cgrp_time_from_cpuctx(cpuctx); - - if (!ctx->nr_active) - goto out; - - if (event_type & EVENT_PINNED) { - list_for_each_entry(event, &ctx->pinned_groups, group_entry) - group_sched_out(event, cpuctx, ctx); - } - - if (event_type & EVENT_FLEXIBLE) { - list_for_each_entry(event, &ctx->flexible_groups, group_entry) - group_sched_out(event, cpuctx, ctx); - } -out: - perf_pmu_enable(ctx->pmu); - raw_spin_unlock(&ctx->lock); -} - -/* - * Test whether two contexts are equivalent, i.e. whether they - * have both been cloned from the same version of the same context - * and they both have the same number of enabled events. - * If the number of enabled events is the same, then the set - * of enabled events should be the same, because these are both - * inherited contexts, therefore we can't access individual events - * in them directly with an fd; we can only enable/disable all - * events via prctl, or enable/disable all events in a family - * via ioctl, which will have the same effect on both contexts. - */ -static int context_equiv(struct perf_event_context *ctx1, - struct perf_event_context *ctx2) -{ - return ctx1->parent_ctx && ctx1->parent_ctx == ctx2->parent_ctx - && ctx1->parent_gen == ctx2->parent_gen - && !ctx1->pin_count && !ctx2->pin_count; -} - -static void __perf_event_sync_stat(struct perf_event *event, - struct perf_event *next_event) -{ - u64 value; - - if (!event->attr.inherit_stat) - return; - - /* - * Update the event value, we cannot use perf_event_read() - * because we're in the middle of a context switch and have IRQs - * disabled, which upsets smp_call_function_single(), however - * we know the event must be on the current CPU, therefore we - * don't need to use it. - */ - switch (event->state) { - case PERF_EVENT_STATE_ACTIVE: - event->pmu->read(event); - /* fall-through */ - - case PERF_EVENT_STATE_INACTIVE: - update_event_times(event); - break; - - default: - break; - } - - /* - * In order to keep per-task stats reliable we need to flip the event - * values when we flip the contexts. - */ - value = local64_read(&next_event->count); - value = local64_xchg(&event->count, value); - local64_set(&next_event->count, value); - - swap(event->total_time_enabled, next_event->total_time_enabled); - swap(event->total_time_running, next_event->total_time_running); - - /* - * Since we swizzled the values, update the user visible data too. - */ - perf_event_update_userpage(event); - perf_event_update_userpage(next_event); -} - -#define list_next_entry(pos, member) \ - list_entry(pos->member.next, typeof(*pos), member) - -static void perf_event_sync_stat(struct perf_event_context *ctx, - struct perf_event_context *next_ctx) -{ - struct perf_event *event, *next_event; - - if (!ctx->nr_stat) - return; - - update_context_time(ctx); - - event = list_first_entry(&ctx->event_list, - struct perf_event, event_entry); - - next_event = list_first_entry(&next_ctx->event_list, - struct perf_event, event_entry); - - while (&event->event_entry != &ctx->event_list && - &next_event->event_entry != &next_ctx->event_list) { - - __perf_event_sync_stat(event, next_event); - - event = list_next_entry(event, event_entry); - next_event = list_next_entry(next_event, event_entry); - } -} - -static void perf_event_context_sched_out(struct task_struct *task, int ctxn, - struct task_struct *next) -{ - struct perf_event_context *ctx = task->perf_event_ctxp[ctxn]; - struct perf_event_context *next_ctx; - struct perf_event_context *parent; - struct perf_cpu_context *cpuctx; - int do_switch = 1; - - if (likely(!ctx)) - return; - - cpuctx = __get_cpu_context(ctx); - if (!cpuctx->task_ctx) - return; - - rcu_read_lock(); - parent = rcu_dereference(ctx->parent_ctx); - next_ctx = next->perf_event_ctxp[ctxn]; - if (parent && next_ctx && - rcu_dereference(next_ctx->parent_ctx) == parent) { - /* - * Looks like the two contexts are clones, so we might be - * able to optimize the context switch. We lock both - * contexts and check that they are clones under the - * lock (including re-checking that neither has been - * uncloned in the meantime). It doesn't matter which - * order we take the locks because no other cpu could - * be trying to lock both of these tasks. - */ - raw_spin_lock(&ctx->lock); - raw_spin_lock_nested(&next_ctx->lock, SINGLE_DEPTH_NESTING); - if (context_equiv(ctx, next_ctx)) { - /* - * XXX do we need a memory barrier of sorts - * wrt to rcu_dereference() of perf_event_ctxp - */ - task->perf_event_ctxp[ctxn] = next_ctx; - next->perf_event_ctxp[ctxn] = ctx; - ctx->task = next; - next_ctx->task = task; - do_switch = 0; - - perf_event_sync_stat(ctx, next_ctx); - } - raw_spin_unlock(&next_ctx->lock); - raw_spin_unlock(&ctx->lock); - } - rcu_read_unlock(); - - if (do_switch) { - ctx_sched_out(ctx, cpuctx, EVENT_ALL); - cpuctx->task_ctx = NULL; - } -} - -#define for_each_task_context_nr(ctxn) \ - for ((ctxn) = 0; (ctxn) < perf_nr_task_contexts; (ctxn)++) - -/* - * Called from scheduler to remove the events of the current task, - * with interrupts disabled. - * - * We stop each event and update the event value in event->count. - * - * This does not protect us against NMI, but disable() - * sets the disabled bit in the control field of event _before_ - * accessing the event control register. If a NMI hits, then it will - * not restart the event. - */ -void __perf_event_task_sched_out(struct task_struct *task, - struct task_struct *next) -{ - int ctxn; - - for_each_task_context_nr(ctxn) - perf_event_context_sched_out(task, ctxn, next); - - /* - * if cgroup events exist on this CPU, then we need - * to check if we have to switch out PMU state. - * cgroup event are system-wide mode only - */ - if (atomic_read(&__get_cpu_var(perf_cgroup_events))) - perf_cgroup_sched_out(task); -} - -static void task_ctx_sched_out(struct perf_event_context *ctx, - enum event_type_t event_type) -{ - struct perf_cpu_context *cpuctx = __get_cpu_context(ctx); - - if (!cpuctx->task_ctx) - return; - - if (WARN_ON_ONCE(ctx != cpuctx->task_ctx)) - return; - - ctx_sched_out(ctx, cpuctx, event_type); - cpuctx->task_ctx = NULL; -} - -/* - * Called with IRQs disabled - */ -static void cpu_ctx_sched_out(struct perf_cpu_context *cpuctx, - enum event_type_t event_type) -{ - ctx_sched_out(&cpuctx->ctx, cpuctx, event_type); -} - -static void -ctx_pinned_sched_in(struct perf_event_context *ctx, - struct perf_cpu_context *cpuctx) -{ - struct perf_event *event; - - list_for_each_entry(event, &ctx->pinned_groups, group_entry) { - if (event->state <= PERF_EVENT_STATE_OFF) - continue; - if (!event_filter_match(event)) - continue; - - /* may need to reset tstamp_enabled */ - if (is_cgroup_event(event)) - perf_cgroup_mark_enabled(event, ctx); - - if (group_can_go_on(event, cpuctx, 1)) - group_sched_in(event, cpuctx, ctx); - - /* - * If this pinned group hasn't been scheduled, - * put it in error state. - */ - if (event->state == PERF_EVENT_STATE_INACTIVE) { - update_group_times(event); - event->state = PERF_EVENT_STATE_ERROR; - } - } -} - -static void -ctx_flexible_sched_in(struct perf_event_context *ctx, - struct perf_cpu_context *cpuctx) -{ - struct perf_event *event; - int can_add_hw = 1; - - list_for_each_entry(event, &ctx->flexible_groups, group_entry) { - /* Ignore events in OFF or ERROR state */ - if (event->state <= PERF_EVENT_STATE_OFF) - continue; - /* - * Listen to the 'cpu' scheduling filter constraint - * of events: - */ - if (!event_filter_match(event)) - continue; - - /* may need to reset tstamp_enabled */ - if (is_cgroup_event(event)) - perf_cgroup_mark_enabled(event, ctx); - - if (group_can_go_on(event, cpuctx, can_add_hw)) { - if (group_sched_in(event, cpuctx, ctx)) - can_add_hw = 0; - } - } -} - -static void -ctx_sched_in(struct perf_event_context *ctx, - struct perf_cpu_context *cpuctx, - enum event_type_t event_type, - struct task_struct *task) -{ - u64 now; - - raw_spin_lock(&ctx->lock); - ctx->is_active = 1; - if (likely(!ctx->nr_events)) - goto out; - - now = perf_clock(); - ctx->timestamp = now; - perf_cgroup_set_timestamp(task, ctx); - /* - * First go through the list and put on any pinned groups - * in order to give them the best chance of going on. - */ - if (event_type & EVENT_PINNED) - ctx_pinned_sched_in(ctx, cpuctx); - - /* Then walk through the lower prio flexible groups */ - if (event_type & EVENT_FLEXIBLE) - ctx_flexible_sched_in(ctx, cpuctx); - -out: - raw_spin_unlock(&ctx->lock); -} - -static void cpu_ctx_sched_in(struct perf_cpu_context *cpuctx, - enum event_type_t event_type, - struct task_struct *task) -{ - struct perf_event_context *ctx = &cpuctx->ctx; - - ctx_sched_in(ctx, cpuctx, event_type, task); -} - -static void task_ctx_sched_in(struct perf_event_context *ctx, - enum event_type_t event_type) -{ - struct perf_cpu_context *cpuctx; - - cpuctx = __get_cpu_context(ctx); - if (cpuctx->task_ctx == ctx) - return; - - ctx_sched_in(ctx, cpuctx, event_type, NULL); - cpuctx->task_ctx = ctx; -} - -static void perf_event_context_sched_in(struct perf_event_context *ctx, - struct task_struct *task) -{ - struct perf_cpu_context *cpuctx; - - cpuctx = __get_cpu_context(ctx); - if (cpuctx->task_ctx == ctx) - return; - - perf_pmu_disable(ctx->pmu); - /* - * We want to keep the following priority order: - * cpu pinned (that don't need to move), task pinned, - * cpu flexible, task flexible. - */ - cpu_ctx_sched_out(cpuctx, EVENT_FLEXIBLE); - - ctx_sched_in(ctx, cpuctx, EVENT_PINNED, task); - cpu_ctx_sched_in(cpuctx, EVENT_FLEXIBLE, task); - ctx_sched_in(ctx, cpuctx, EVENT_FLEXIBLE, task); - - cpuctx->task_ctx = ctx; - - /* - * Since these rotations are per-cpu, we need to ensure the - * cpu-context we got scheduled on is actually rotating. - */ - perf_pmu_rotate_start(ctx->pmu); - perf_pmu_enable(ctx->pmu); -} - -/* - * Called from scheduler to add the events of the current task - * with interrupts disabled. - * - * We restore the event value and then enable it. - * - * This does not protect us against NMI, but enable() - * sets the enabled bit in the control field of event _before_ - * accessing the event control register. If a NMI hits, then it will - * keep the event running. - */ -void __perf_event_task_sched_in(struct task_struct *task) -{ - struct perf_event_context *ctx; - int ctxn; - - for_each_task_context_nr(ctxn) { - ctx = task->perf_event_ctxp[ctxn]; - if (likely(!ctx)) - continue; - - perf_event_context_sched_in(ctx, task); - } - /* - * if cgroup events exist on this CPU, then we need - * to check if we have to switch in PMU state. - * cgroup event are system-wide mode only - */ - if (atomic_read(&__get_cpu_var(perf_cgroup_events))) - perf_cgroup_sched_in(task); -} - -static u64 perf_calculate_period(struct perf_event *event, u64 nsec, u64 count) -{ - u64 frequency = event->attr.sample_freq; - u64 sec = NSEC_PER_SEC; - u64 divisor, dividend; - - int count_fls, nsec_fls, frequency_fls, sec_fls; - - count_fls = fls64(count); - nsec_fls = fls64(nsec); - frequency_fls = fls64(frequency); - sec_fls = 30; - - /* - * We got @count in @nsec, with a target of sample_freq HZ - * the target period becomes: - * - * @count * 10^9 - * period = ------------------- - * @nsec * sample_freq - * - */ - - /* - * Reduce accuracy by one bit such that @a and @b converge - * to a similar magnitude. - */ -#define REDUCE_FLS(a, b) \ -do { \ - if (a##_fls > b##_fls) { \ - a >>= 1; \ - a##_fls--; \ - } else { \ - b >>= 1; \ - b##_fls--; \ - } \ -} while (0) - - /* - * Reduce accuracy until either term fits in a u64, then proceed with - * the other, so that finally we can do a u64/u64 division. - */ - while (count_fls + sec_fls > 64 && nsec_fls + frequency_fls > 64) { - REDUCE_FLS(nsec, frequency); - REDUCE_FLS(sec, count); - } - - if (count_fls + sec_fls > 64) { - divisor = nsec * frequency; - - while (count_fls + sec_fls > 64) { - REDUCE_FLS(count, sec); - divisor >>= 1; - } - - dividend = count * sec; - } else { - dividend = count * sec; - - while (nsec_fls + frequency_fls > 64) { - REDUCE_FLS(nsec, frequency); - dividend >>= 1; - } - - divisor = nsec * frequency; - } - - if (!divisor) - return dividend; - - return div64_u64(dividend, divisor); -} - -static void perf_adjust_period(struct perf_event *event, u64 nsec, u64 count) -{ - struct hw_perf_event *hwc = &event->hw; - s64 period, sample_period; - s64 delta; - - period = perf_calculate_period(event, nsec, count); - - delta = (s64)(period - hwc->sample_period); - delta = (delta + 7) / 8; /* low pass filter */ - - sample_period = hwc->sample_period + delta; - - if (!sample_period) - sample_period = 1; - - hwc->sample_period = sample_period; - - if (local64_read(&hwc->period_left) > 8*sample_period) { - event->pmu->stop(event, PERF_EF_UPDATE); - local64_set(&hwc->period_left, 0); - event->pmu->start(event, PERF_EF_RELOAD); - } -} - -static void perf_ctx_adjust_freq(struct perf_event_context *ctx, u64 period) -{ - struct perf_event *event; - struct hw_perf_event *hwc; - u64 interrupts, now; - s64 delta; - - raw_spin_lock(&ctx->lock); - list_for_each_entry_rcu(event, &ctx->event_list, event_entry) { - if (event->state != PERF_EVENT_STATE_ACTIVE) - continue; - - if (!event_filter_match(event)) - continue; - - hwc = &event->hw; - - interrupts = hwc->interrupts; - hwc->interrupts = 0; - - /* - * unthrottle events on the tick - */ - if (interrupts == MAX_INTERRUPTS) { - perf_log_throttle(event, 1); - event->pmu->start(event, 0); - } - - if (!event->attr.freq || !event->attr.sample_freq) - continue; - - event->pmu->read(event); - now = local64_read(&event->count); - delta = now - hwc->freq_count_stamp; - hwc->freq_count_stamp = now; - - if (delta > 0) - perf_adjust_period(event, period, delta); - } - raw_spin_unlock(&ctx->lock); -} - -/* - * Round-robin a context's events: - */ -static void rotate_ctx(struct perf_event_context *ctx) -{ - raw_spin_lock(&ctx->lock); - - /* - * Rotate the first entry last of non-pinned groups. Rotation might be - * disabled by the inheritance code. - */ - if (!ctx->rotate_disable) - list_rotate_left(&ctx->flexible_groups); - - raw_spin_unlock(&ctx->lock); -} - -/* - * perf_pmu_rotate_start() and perf_rotate_context() are fully serialized - * because they're strictly cpu affine and rotate_start is called with IRQs - * disabled, while rotate_context is called from IRQ context. - */ -static void perf_rotate_context(struct perf_cpu_context *cpuctx) -{ - u64 interval = (u64)cpuctx->jiffies_interval * TICK_NSEC; - struct perf_event_context *ctx = NULL; - int rotate = 0, remove = 1; - - if (cpuctx->ctx.nr_events) { - remove = 0; - if (cpuctx->ctx.nr_events != cpuctx->ctx.nr_active) - rotate = 1; - } - - ctx = cpuctx->task_ctx; - if (ctx && ctx->nr_events) { - remove = 0; - if (ctx->nr_events != ctx->nr_active) - rotate = 1; - } - - perf_pmu_disable(cpuctx->ctx.pmu); - perf_ctx_adjust_freq(&cpuctx->ctx, interval); - if (ctx) - perf_ctx_adjust_freq(ctx, interval); - - if (!rotate) - goto done; - - cpu_ctx_sched_out(cpuctx, EVENT_FLEXIBLE); - if (ctx) - task_ctx_sched_out(ctx, EVENT_FLEXIBLE); - - rotate_ctx(&cpuctx->ctx); - if (ctx) - rotate_ctx(ctx); - - cpu_ctx_sched_in(cpuctx, EVENT_FLEXIBLE, current); - if (ctx) - task_ctx_sched_in(ctx, EVENT_FLEXIBLE); - -done: - if (remove) - list_del_init(&cpuctx->rotation_list); - - perf_pmu_enable(cpuctx->ctx.pmu); -} - -void perf_event_task_tick(void) -{ - struct list_head *head = &__get_cpu_var(rotation_list); - struct perf_cpu_context *cpuctx, *tmp; - - WARN_ON(!irqs_disabled()); - - list_for_each_entry_safe(cpuctx, tmp, head, rotation_list) { - if (cpuctx->jiffies_interval == 1 || - !(jiffies % cpuctx->jiffies_interval)) - perf_rotate_context(cpuctx); - } -} - -static int event_enable_on_exec(struct perf_event *event, - struct perf_event_context *ctx) -{ - if (!event->attr.enable_on_exec) - return 0; - - event->attr.enable_on_exec = 0; - if (event->state >= PERF_EVENT_STATE_INACTIVE) - return 0; - - __perf_event_mark_enabled(event, ctx); - - return 1; -} - -/* - * Enable all of a task's events that have been marked enable-on-exec. - * This expects task == current. - */ -static void perf_event_enable_on_exec(struct perf_event_context *ctx) -{ - struct perf_event *event; - unsigned long flags; - int enabled = 0; - int ret; - - local_irq_save(flags); - if (!ctx || !ctx->nr_events) - goto out; - - /* - * We must ctxsw out cgroup events to avoid conflict - * when invoking perf_task_event_sched_in() later on - * in this function. Otherwise we end up trying to - * ctxswin cgroup events which are already scheduled - * in. - */ - perf_cgroup_sched_out(current); - task_ctx_sched_out(ctx, EVENT_ALL); - - raw_spin_lock(&ctx->lock); - - list_for_each_entry(event, &ctx->pinned_groups, group_entry) { - ret = event_enable_on_exec(event, ctx); - if (ret) - enabled = 1; - } - - list_for_each_entry(event, &ctx->flexible_groups, group_entry) { - ret = event_enable_on_exec(event, ctx); - if (ret) - enabled = 1; - } - - /* - * Unclone this context if we enabled any event. - */ - if (enabled) - unclone_ctx(ctx); - - raw_spin_unlock(&ctx->lock); - - /* - * Also calls ctxswin for cgroup events, if any: - */ - perf_event_context_sched_in(ctx, ctx->task); -out: - local_irq_restore(flags); -} - -/* - * Cross CPU call to read the hardware event - */ -static void __perf_event_read(void *info) -{ - struct perf_event *event = info; - struct perf_event_context *ctx = event->ctx; - struct perf_cpu_context *cpuctx = __get_cpu_context(ctx); - - /* - * If this is a task context, we need to check whether it is - * the current task context of this cpu. If not it has been - * scheduled out before the smp call arrived. In that case - * event->count would have been updated to a recent sample - * when the event was scheduled out. - */ - if (ctx->task && cpuctx->task_ctx != ctx) - return; - - raw_spin_lock(&ctx->lock); - if (ctx->is_active) { - update_context_time(ctx); - update_cgrp_time_from_event(event); - } - update_event_times(event); - if (event->state == PERF_EVENT_STATE_ACTIVE) - event->pmu->read(event); - raw_spin_unlock(&ctx->lock); -} - -static inline u64 perf_event_count(struct perf_event *event) -{ - return local64_read(&event->count) + atomic64_read(&event->child_count); -} - -static u64 perf_event_read(struct perf_event *event) -{ - /* - * If event is enabled and currently active on a CPU, update the - * value in the event structure: - */ - if (event->state == PERF_EVENT_STATE_ACTIVE) { - smp_call_function_single(event->oncpu, - __perf_event_read, event, 1); - } else if (event->state == PERF_EVENT_STATE_INACTIVE) { - struct perf_event_context *ctx = event->ctx; - unsigned long flags; - - raw_spin_lock_irqsave(&ctx->lock, flags); - /* - * may read while context is not active - * (e.g., thread is blocked), in that case - * we cannot update context time - */ - if (ctx->is_active) { - update_context_time(ctx); - update_cgrp_time_from_event(event); - } - update_event_times(event); - raw_spin_unlock_irqrestore(&ctx->lock, flags); - } - - return perf_event_count(event); -} - -/* - * Callchain support - */ - -struct callchain_cpus_entries { - struct rcu_head rcu_head; - struct perf_callchain_entry *cpu_entries[0]; -}; - -static DEFINE_PER_CPU(int, callchain_recursion[PERF_NR_CONTEXTS]); -static atomic_t nr_callchain_events; -static DEFINE_MUTEX(callchain_mutex); -struct callchain_cpus_entries *callchain_cpus_entries; - - -__weak void perf_callchain_kernel(struct perf_callchain_entry *entry, - struct pt_regs *regs) -{ -} - -__weak void perf_callchain_user(struct perf_callchain_entry *entry, - struct pt_regs *regs) -{ -} - -static void release_callchain_buffers_rcu(struct rcu_head *head) -{ - struct callchain_cpus_entries *entries; - int cpu; - - entries = container_of(head, struct callchain_cpus_entries, rcu_head); - - for_each_possible_cpu(cpu) - kfree(entries->cpu_entries[cpu]); - - kfree(entries); -} - -static void release_callchain_buffers(void) -{ - struct callchain_cpus_entries *entries; - - entries = callchain_cpus_entries; - rcu_assign_pointer(callchain_cpus_entries, NULL); - call_rcu(&entries->rcu_head, release_callchain_buffers_rcu); -} - -static int alloc_callchain_buffers(void) -{ - int cpu; - int size; - struct callchain_cpus_entries *entries; - - /* - * We can't use the percpu allocation API for data that can be - * accessed from NMI. Use a temporary manual per cpu allocation - * until that gets sorted out. - */ - size = offsetof(struct callchain_cpus_entries, cpu_entries[nr_cpu_ids]); - - entries = kzalloc(size, GFP_KERNEL); - if (!entries) - return -ENOMEM; - - size = sizeof(struct perf_callchain_entry) * PERF_NR_CONTEXTS; - - for_each_possible_cpu(cpu) { - entries->cpu_entries[cpu] = kmalloc_node(size, GFP_KERNEL, - cpu_to_node(cpu)); - if (!entries->cpu_entries[cpu]) - goto fail; - } - - rcu_assign_pointer(callchain_cpus_entries, entries); - - return 0; - -fail: - for_each_possible_cpu(cpu) - kfree(entries->cpu_entries[cpu]); - kfree(entries); - - return -ENOMEM; -} - -static int get_callchain_buffers(void) -{ - int err = 0; - int count; - - mutex_lock(&callchain_mutex); - - count = atomic_inc_return(&nr_callchain_events); - if (WARN_ON_ONCE(count < 1)) { - err = -EINVAL; - goto exit; - } - - if (count > 1) { - /* If the allocation failed, give up */ - if (!callchain_cpus_entries) - err = -ENOMEM; - goto exit; - } - - err = alloc_callchain_buffers(); - if (err) - release_callchain_buffers(); -exit: - mutex_unlock(&callchain_mutex); - - return err; -} - -static void put_callchain_buffers(void) -{ - if (atomic_dec_and_mutex_lock(&nr_callchain_events, &callchain_mutex)) { - release_callchain_buffers(); - mutex_unlock(&callchain_mutex); - } -} - -static int get_recursion_context(int *recursion) -{ - int rctx; - - if (in_nmi()) - rctx = 3; - else if (in_irq()) - rctx = 2; - else if (in_softirq()) - rctx = 1; - else - rctx = 0; - - if (recursion[rctx]) - return -1; - - recursion[rctx]++; - barrier(); - - return rctx; -} - -static inline void put_recursion_context(int *recursion, int rctx) -{ - barrier(); - recursion[rctx]--; -} - -static struct perf_callchain_entry *get_callchain_entry(int *rctx) -{ - int cpu; - struct callchain_cpus_entries *entries; - - *rctx = get_recursion_context(__get_cpu_var(callchain_recursion)); - if (*rctx == -1) - return NULL; - - entries = rcu_dereference(callchain_cpus_entries); - if (!entries) - return NULL; - - cpu = smp_processor_id(); - - return &entries->cpu_entries[cpu][*rctx]; -} - -static void -put_callchain_entry(int rctx) -{ - put_recursion_context(__get_cpu_var(callchain_recursion), rctx); -} - -static struct perf_callchain_entry *perf_callchain(struct pt_regs *regs) -{ - int rctx; - struct perf_callchain_entry *entry; - - - entry = get_callchain_entry(&rctx); - if (rctx == -1) - return NULL; - - if (!entry) - goto exit_put; - - entry->nr = 0; - - if (!user_mode(regs)) { - perf_callchain_store(entry, PERF_CONTEXT_KERNEL); - perf_callchain_kernel(entry, regs); - if (current->mm) - regs = task_pt_regs(current); - else - regs = NULL; - } - - if (regs) { - perf_callchain_store(entry, PERF_CONTEXT_USER); - perf_callchain_user(entry, regs); - } - -exit_put: - put_callchain_entry(rctx); - - return entry; -} - -/* - * Initialize the perf_event context in a task_struct: - */ -static void __perf_event_init_context(struct perf_event_context *ctx) -{ - raw_spin_lock_init(&ctx->lock); - mutex_init(&ctx->mutex); - INIT_LIST_HEAD(&ctx->pinned_groups); - INIT_LIST_HEAD(&ctx->flexible_groups); - INIT_LIST_HEAD(&ctx->event_list); - atomic_set(&ctx->refcount, 1); -} - -static struct perf_event_context * -alloc_perf_context(struct pmu *pmu, struct task_struct *task) -{ - struct perf_event_context *ctx; - - ctx = kzalloc(sizeof(struct perf_event_context), GFP_KERNEL); - if (!ctx) - return NULL; - - __perf_event_init_context(ctx); - if (task) { - ctx->task = task; - get_task_struct(task); - } - ctx->pmu = pmu; - - return ctx; -} - -static struct task_struct * -find_lively_task_by_vpid(pid_t vpid) -{ - struct task_struct *task; - int err; - - rcu_read_lock(); - if (!vpid) - task = current; - else - task = find_task_by_vpid(vpid); - if (task) - get_task_struct(task); - rcu_read_unlock(); - - if (!task) - return ERR_PTR(-ESRCH); - - /* Reuse ptrace permission checks for now. */ - err = -EACCES; - if (!ptrace_may_access(task, PTRACE_MODE_READ)) - goto errout; - - return task; -errout: - put_task_struct(task); - return ERR_PTR(err); - -} - -/* - * Returns a matching context with refcount and pincount. - */ -static struct perf_event_context * -find_get_context(struct pmu *pmu, struct task_struct *task, int cpu) -{ - struct perf_event_context *ctx; - struct perf_cpu_context *cpuctx; - unsigned long flags; - int ctxn, err; - - if (!task) { - /* Must be root to operate on a CPU event: */ - if (perf_paranoid_cpu() && !capable(CAP_SYS_ADMIN)) - return ERR_PTR(-EACCES); - - /* - * We could be clever and allow to attach a event to an - * offline CPU and activate it when the CPU comes up, but - * that's for later. - */ - if (!cpu_online(cpu)) - return ERR_PTR(-ENODEV); - - cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu); - ctx = &cpuctx->ctx; - get_ctx(ctx); - ++ctx->pin_count; - - return ctx; - } - - err = -EINVAL; - ctxn = pmu->task_ctx_nr; - if (ctxn < 0) - goto errout; - -retry: - ctx = perf_lock_task_context(task, ctxn, &flags); - if (ctx) { - unclone_ctx(ctx); - ++ctx->pin_count; - raw_spin_unlock_irqrestore(&ctx->lock, flags); - } - - if (!ctx) { - ctx = alloc_perf_context(pmu, task); - err = -ENOMEM; - if (!ctx) - goto errout; - - get_ctx(ctx); - - err = 0; - mutex_lock(&task->perf_event_mutex); - /* - * If it has already passed perf_event_exit_task(). - * we must see PF_EXITING, it takes this mutex too. - */ - if (task->flags & PF_EXITING) - err = -ESRCH; - else if (task->perf_event_ctxp[ctxn]) - err = -EAGAIN; - else { - ++ctx->pin_count; - rcu_assign_pointer(task->perf_event_ctxp[ctxn], ctx); - } - mutex_unlock(&task->perf_event_mutex); - - if (unlikely(err)) { - put_task_struct(task); - kfree(ctx); - - if (err == -EAGAIN) - goto retry; - goto errout; - } - } - - return ctx; - -errout: - return ERR_PTR(err); -} - -static void perf_event_free_filter(struct perf_event *event); - -static void free_event_rcu(struct rcu_head *head) -{ - struct perf_event *event; - - event = container_of(head, struct perf_event, rcu_head); - if (event->ns) - put_pid_ns(event->ns); - perf_event_free_filter(event); - kfree(event); -} - -static void perf_buffer_put(struct perf_buffer *buffer); - -static void free_event(struct perf_event *event) -{ - irq_work_sync(&event->pending); - - if (!event->parent) { - if (event->attach_state & PERF_ATTACH_TASK) - jump_label_dec(&perf_sched_events); - if (event->attr.mmap || event->attr.mmap_data) - atomic_dec(&nr_mmap_events); - if (event->attr.comm) - atomic_dec(&nr_comm_events); - if (event->attr.task) - atomic_dec(&nr_task_events); - if (event->attr.sample_type & PERF_SAMPLE_CALLCHAIN) - put_callchain_buffers(); - if (is_cgroup_event(event)) { - atomic_dec(&per_cpu(perf_cgroup_events, event->cpu)); - jump_label_dec(&perf_sched_events); - } - } - - if (event->buffer) { - perf_buffer_put(event->buffer); - event->buffer = NULL; - } - - if (is_cgroup_event(event)) - perf_detach_cgroup(event); - - if (event->destroy) - event->destroy(event); - - if (event->ctx) - put_ctx(event->ctx); - - call_rcu(&event->rcu_head, free_event_rcu); -} - -int perf_event_release_kernel(struct perf_event *event) -{ - struct perf_event_context *ctx = event->ctx; - - /* - * Remove from the PMU, can't get re-enabled since we got - * here because the last ref went. - */ - perf_event_disable(event); - - WARN_ON_ONCE(ctx->parent_ctx); - /* - * There are two ways this annotation is useful: - * - * 1) there is a lock recursion from perf_event_exit_task - * see the comment there. - * - * 2) there is a lock-inversion with mmap_sem through - * perf_event_read_group(), which takes faults while - * holding ctx->mutex, however this is called after - * the last filedesc died, so there is no possibility - * to trigger the AB-BA case. - */ - mutex_lock_nested(&ctx->mutex, SINGLE_DEPTH_NESTING); - raw_spin_lock_irq(&ctx->lock); - perf_group_detach(event); - list_del_event(event, ctx); - raw_spin_unlock_irq(&ctx->lock); - mutex_unlock(&ctx->mutex); - - free_event(event); - - return 0; -} -EXPORT_SYMBOL_GPL(perf_event_release_kernel); - -/* - * Called when the last reference to the file is gone. - */ -static int perf_release(struct inode *inode, struct file *file) -{ - struct perf_event *event = file->private_data; - struct task_struct *owner; - - file->private_data = NULL; - - rcu_read_lock(); - owner = ACCESS_ONCE(event->owner); - /* - * Matches the smp_wmb() in perf_event_exit_task(). If we observe - * !owner it means the list deletion is complete and we can indeed - * free this event, otherwise we need to serialize on - * owner->perf_event_mutex. - */ - smp_read_barrier_depends(); - if (owner) { - /* - * Since delayed_put_task_struct() also drops the last - * task reference we can safely take a new reference - * while holding the rcu_read_lock(). - */ - get_task_struct(owner); - } - rcu_read_unlock(); - - if (owner) { - mutex_lock(&owner->perf_event_mutex); - /* - * We have to re-check the event->owner field, if it is cleared - * we raced with perf_event_exit_task(), acquiring the mutex - * ensured they're done, and we can proceed with freeing the - * event. - */ - if (event->owner) - list_del_init(&event->owner_entry); - mutex_unlock(&owner->perf_event_mutex); - put_task_struct(owner); - } - - return perf_event_release_kernel(event); -} - -u64 perf_event_read_value(struct perf_event *event, u64 *enabled, u64 *running) -{ - struct perf_event *child; - u64 total = 0; - - *enabled = 0; - *running = 0; - - mutex_lock(&event->child_mutex); - total += perf_event_read(event); - *enabled += event->total_time_enabled + - atomic64_read(&event->child_total_time_enabled); - *running += event->total_time_running + - atomic64_read(&event->child_total_time_running); - - list_for_each_entry(child, &event->child_list, child_list) { - total += perf_event_read(child); - *enabled += child->total_time_enabled; - *running += child->total_time_running; - } - mutex_unlock(&event->child_mutex); - - return total; -} -EXPORT_SYMBOL_GPL(perf_event_read_value); - -static int perf_event_read_group(struct perf_event *event, - u64 read_format, char __user *buf) -{ - struct perf_event *leader = event->group_leader, *sub; - int n = 0, size = 0, ret = -EFAULT; - struct perf_event_context *ctx = leader->ctx; - u64 values[5]; - u64 count, enabled, running; - - mutex_lock(&ctx->mutex); - count = perf_event_read_value(leader, &enabled, &running); - - values[n++] = 1 + leader->nr_siblings; - if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED) - values[n++] = enabled; - if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING) - values[n++] = running; - values[n++] = count; - if (read_format & PERF_FORMAT_ID) - values[n++] = primary_event_id(leader); - - size = n * sizeof(u64); - - if (copy_to_user(buf, values, size)) - goto unlock; - - ret = size; - - list_for_each_entry(sub, &leader->sibling_list, group_entry) { - n = 0; - - values[n++] = perf_event_read_value(sub, &enabled, &running); - if (read_format & PERF_FORMAT_ID) - values[n++] = primary_event_id(sub); - - size = n * sizeof(u64); - - if (copy_to_user(buf + ret, values, size)) { - ret = -EFAULT; - goto unlock; - } - - ret += size; - } -unlock: - mutex_unlock(&ctx->mutex); - - return ret; -} - -static int perf_event_read_one(struct perf_event *event, - u64 read_format, char __user *buf) -{ - u64 enabled, running; - u64 values[4]; - int n = 0; - - values[n++] = perf_event_read_value(event, &enabled, &running); - if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED) - values[n++] = enabled; - if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING) - values[n++] = running; - if (read_format & PERF_FORMAT_ID) - values[n++] = primary_event_id(event); - - if (copy_to_user(buf, values, n * sizeof(u64))) - return -EFAULT; - - return n * sizeof(u64); -} - -/* - * Read the performance event - simple non blocking version for now - */ -static ssize_t -perf_read_hw(struct perf_event *event, char __user *buf, size_t count) -{ - u64 read_format = event->attr.read_format; - int ret; - - /* - * Return end-of-file for a read on a event that is in - * error state (i.e. because it was pinned but it couldn't be - * scheduled on to the CPU at some point). - */ - if (event->state == PERF_EVENT_STATE_ERROR) - return 0; - - if (count < event->read_size) - return -ENOSPC; - - WARN_ON_ONCE(event->ctx->parent_ctx); - if (read_format & PERF_FORMAT_GROUP) - ret = perf_event_read_group(event, read_format, buf); - else - ret = perf_event_read_one(event, read_format, buf); - - return ret; -} - -static ssize_t -perf_read(struct file *file, char __user *buf, size_t count, loff_t *ppos) -{ - struct perf_event *event = file->private_data; - - return perf_read_hw(event, buf, count); -} - -static unsigned int perf_poll(struct file *file, poll_table *wait) -{ - struct perf_event *event = file->private_data; - struct perf_buffer *buffer; - unsigned int events = POLL_HUP; - - rcu_read_lock(); - buffer = rcu_dereference(event->buffer); - if (buffer) - events = atomic_xchg(&buffer->poll, 0); - rcu_read_unlock(); - - poll_wait(file, &event->waitq, wait); - - return events; -} - -static void perf_event_reset(struct perf_event *event) -{ - (void)perf_event_read(event); - local64_set(&event->count, 0); - perf_event_update_userpage(event); -} - -/* - * Holding the top-level event's child_mutex means that any - * descendant process that has inherited this event will block - * in sync_child_event if it goes to exit, thus satisfying the - * task existence requirements of perf_event_enable/disable. - */ -static void perf_event_for_each_child(struct perf_event *event, - void (*func)(struct perf_event *)) -{ - struct perf_event *child; - - WARN_ON_ONCE(event->ctx->parent_ctx); - mutex_lock(&event->child_mutex); - func(event); - list_for_each_entry(child, &event->child_list, child_list) - func(child); - mutex_unlock(&event->child_mutex); -} - -static void perf_event_for_each(struct perf_event *event, - void (*func)(struct perf_event *)) -{ - struct perf_event_context *ctx = event->ctx; - struct perf_event *sibling; - - WARN_ON_ONCE(ctx->parent_ctx); - mutex_lock(&ctx->mutex); - event = event->group_leader; - - perf_event_for_each_child(event, func); - func(event); - list_for_each_entry(sibling, &event->sibling_list, group_entry) - perf_event_for_each_child(event, func); - mutex_unlock(&ctx->mutex); -} - -static int perf_event_period(struct perf_event *event, u64 __user *arg) -{ - struct perf_event_context *ctx = event->ctx; - int ret = 0; - u64 value; - - if (!is_sampling_event(event)) - return -EINVAL; - - if (copy_from_user(&value, arg, sizeof(value))) - return -EFAULT; - - if (!value) - return -EINVAL; - - raw_spin_lock_irq(&ctx->lock); - if (event->attr.freq) { - if (value > sysctl_perf_event_sample_rate) { - ret = -EINVAL; - goto unlock; - } - - event->attr.sample_freq = value; - } else { - event->attr.sample_period = value; - event->hw.sample_period = value; - } -unlock: - raw_spin_unlock_irq(&ctx->lock); - - return ret; -} - -static const struct file_operations perf_fops; - -static struct perf_event *perf_fget_light(int fd, int *fput_needed) -{ - struct file *file; - - file = fget_light(fd, fput_needed); - if (!file) - return ERR_PTR(-EBADF); - - if (file->f_op != &perf_fops) { - fput_light(file, *fput_needed); - *fput_needed = 0; - return ERR_PTR(-EBADF); - } - - return file->private_data; -} - -static int perf_event_set_output(struct perf_event *event, - struct perf_event *output_event); -static int perf_event_set_filter(struct perf_event *event, void __user *arg); - -static long perf_ioctl(struct file *file, unsigned int cmd, unsigned long arg) -{ - struct perf_event *event = file->private_data; - void (*func)(struct perf_event *); - u32 flags = arg; - - switch (cmd) { - case PERF_EVENT_IOC_ENABLE: - func = perf_event_enable; - break; - case PERF_EVENT_IOC_DISABLE: - func = perf_event_disable; - break; - case PERF_EVENT_IOC_RESET: - func = perf_event_reset; - break; - - case PERF_EVENT_IOC_REFRESH: - return perf_event_refresh(event, arg); - - case PERF_EVENT_IOC_PERIOD: - return perf_event_period(event, (u64 __user *)arg); - - case PERF_EVENT_IOC_SET_OUTPUT: - { - struct perf_event *output_event = NULL; - int fput_needed = 0; - int ret; - - if (arg != -1) { - output_event = perf_fget_light(arg, &fput_needed); - if (IS_ERR(output_event)) - return PTR_ERR(output_event); - } - - ret = perf_event_set_output(event, output_event); - if (output_event) - fput_light(output_event->filp, fput_needed); - - return ret; - } - - case PERF_EVENT_IOC_SET_FILTER: - return perf_event_set_filter(event, (void __user *)arg); - - default: - return -ENOTTY; - } - - if (flags & PERF_IOC_FLAG_GROUP) - perf_event_for_each(event, func); - else - perf_event_for_each_child(event, func); - - return 0; -} - -int perf_event_task_enable(void) -{ - struct perf_event *event; - - mutex_lock(¤t->perf_event_mutex); - list_for_each_entry(event, ¤t->perf_event_list, owner_entry) - perf_event_for_each_child(event, perf_event_enable); - mutex_unlock(¤t->perf_event_mutex); - - return 0; -} - -int perf_event_task_disable(void) -{ - struct perf_event *event; - - mutex_lock(¤t->perf_event_mutex); - list_for_each_entry(event, ¤t->perf_event_list, owner_entry) - perf_event_for_each_child(event, perf_event_disable); - mutex_unlock(¤t->perf_event_mutex); - - return 0; -} - -#ifndef PERF_EVENT_INDEX_OFFSET -# define PERF_EVENT_INDEX_OFFSET 0 -#endif - -static int perf_event_index(struct perf_event *event) -{ - if (event->hw.state & PERF_HES_STOPPED) - return 0; - - if (event->state != PERF_EVENT_STATE_ACTIVE) - return 0; - - return event->hw.idx + 1 - PERF_EVENT_INDEX_OFFSET; -} - -/* - * Callers need to ensure there can be no nesting of this function, otherwise - * the seqlock logic goes bad. We can not serialize this because the arch - * code calls this from NMI context. - */ -void perf_event_update_userpage(struct perf_event *event) -{ - struct perf_event_mmap_page *userpg; - struct perf_buffer *buffer; - - rcu_read_lock(); - buffer = rcu_dereference(event->buffer); - if (!buffer) - goto unlock; - - userpg = buffer->user_page; - - /* - * Disable preemption so as to not let the corresponding user-space - * spin too long if we get preempted. - */ - preempt_disable(); - ++userpg->lock; - barrier(); - userpg->index = perf_event_index(event); - userpg->offset = perf_event_count(event); - if (event->state == PERF_EVENT_STATE_ACTIVE) - userpg->offset -= local64_read(&event->hw.prev_count); - - userpg->time_enabled = event->total_time_enabled + - atomic64_read(&event->child_total_time_enabled); - - userpg->time_running = event->total_time_running + - atomic64_read(&event->child_total_time_running); - - barrier(); - ++userpg->lock; - preempt_enable(); -unlock: - rcu_read_unlock(); -} - -static unsigned long perf_data_size(struct perf_buffer *buffer); - -static void -perf_buffer_init(struct perf_buffer *buffer, long watermark, int flags) -{ - long max_size = perf_data_size(buffer); - - if (watermark) - buffer->watermark = min(max_size, watermark); - - if (!buffer->watermark) - buffer->watermark = max_size / 2; - - if (flags & PERF_BUFFER_WRITABLE) - buffer->writable = 1; - - atomic_set(&buffer->refcount, 1); -} - -#ifndef CONFIG_PERF_USE_VMALLOC - -/* - * Back perf_mmap() with regular GFP_KERNEL-0 pages. - */ - -static struct page * -perf_mmap_to_page(struct perf_buffer *buffer, unsigned long pgoff) -{ - if (pgoff > buffer->nr_pages) - return NULL; - - if (pgoff == 0) - return virt_to_page(buffer->user_page); - - return virt_to_page(buffer->data_pages[pgoff - 1]); -} - -static void *perf_mmap_alloc_page(int cpu) -{ - struct page *page; - int node; - - node = (cpu == -1) ? cpu : cpu_to_node(cpu); - page = alloc_pages_node(node, GFP_KERNEL | __GFP_ZERO, 0); - if (!page) - return NULL; - - return page_address(page); -} - -static struct perf_buffer * -perf_buffer_alloc(int nr_pages, long watermark, int cpu, int flags) -{ - struct perf_buffer *buffer; - unsigned long size; - int i; - - size = sizeof(struct perf_buffer); - size += nr_pages * sizeof(void *); - - buffer = kzalloc(size, GFP_KERNEL); - if (!buffer) - goto fail; - - buffer->user_page = perf_mmap_alloc_page(cpu); - if (!buffer->user_page) - goto fail_user_page; - - for (i = 0; i < nr_pages; i++) { - buffer->data_pages[i] = perf_mmap_alloc_page(cpu); - if (!buffer->data_pages[i]) - goto fail_data_pages; - } - - buffer->nr_pages = nr_pages; - - perf_buffer_init(buffer, watermark, flags); - - return buffer; - -fail_data_pages: - for (i--; i >= 0; i--) - free_page((unsigned long)buffer->data_pages[i]); - - free_page((unsigned long)buffer->user_page); - -fail_user_page: - kfree(buffer); - -fail: - return NULL; -} - -static void perf_mmap_free_page(unsigned long addr) -{ - struct page *page = virt_to_page((void *)addr); - - page->mapping = NULL; - __free_page(page); -} - -static void perf_buffer_free(struct perf_buffer *buffer) -{ - int i; - - perf_mmap_free_page((unsigned long)buffer->user_page); - for (i = 0; i < buffer->nr_pages; i++) - perf_mmap_free_page((unsigned long)buffer->data_pages[i]); - kfree(buffer); -} - -static inline int page_order(struct perf_buffer *buffer) -{ - return 0; -} - -#else - -/* - * Back perf_mmap() with vmalloc memory. - * - * Required for architectures that have d-cache aliasing issues. - */ - -static inline int page_order(struct perf_buffer *buffer) -{ - return buffer->page_order; -} - -static struct page * -perf_mmap_to_page(struct perf_buffer *buffer, unsigned long pgoff) -{ - if (pgoff > (1UL << page_order(buffer))) - return NULL; - - return vmalloc_to_page((void *)buffer->user_page + pgoff * PAGE_SIZE); -} - -static void perf_mmap_unmark_page(void *addr) -{ - struct page *page = vmalloc_to_page(addr); - - page->mapping = NULL; -} - -static void perf_buffer_free_work(struct work_struct *work) -{ - struct perf_buffer *buffer; - void *base; - int i, nr; - - buffer = container_of(work, struct perf_buffer, work); - nr = 1 << page_order(buffer); - - base = buffer->user_page; - for (i = 0; i < nr + 1; i++) - perf_mmap_unmark_page(base + (i * PAGE_SIZE)); - - vfree(base); - kfree(buffer); -} - -static void perf_buffer_free(struct perf_buffer *buffer) -{ - schedule_work(&buffer->work); -} - -static struct perf_buffer * -perf_buffer_alloc(int nr_pages, long watermark, int cpu, int flags) -{ - struct perf_buffer *buffer; - unsigned long size; - void *all_buf; - - size = sizeof(struct perf_buffer); - size += sizeof(void *); - - buffer = kzalloc(size, GFP_KERNEL); - if (!buffer) - goto fail; - - INIT_WORK(&buffer->work, perf_buffer_free_work); - - all_buf = vmalloc_user((nr_pages + 1) * PAGE_SIZE); - if (!all_buf) - goto fail_all_buf; - - buffer->user_page = all_buf; - buffer->data_pages[0] = all_buf + PAGE_SIZE; - buffer->page_order = ilog2(nr_pages); - buffer->nr_pages = 1; - - perf_buffer_init(buffer, watermark, flags); - - return buffer; - -fail_all_buf: - kfree(buffer); - -fail: - return NULL; -} - -#endif - -static unsigned long perf_data_size(struct perf_buffer *buffer) -{ - return buffer->nr_pages << (PAGE_SHIFT + page_order(buffer)); -} - -static int perf_mmap_fault(struct vm_area_struct *vma, struct vm_fault *vmf) -{ - struct perf_event *event = vma->vm_file->private_data; - struct perf_buffer *buffer; - int ret = VM_FAULT_SIGBUS; - - if (vmf->flags & FAULT_FLAG_MKWRITE) { - if (vmf->pgoff == 0) - ret = 0; - return ret; - } - - rcu_read_lock(); - buffer = rcu_dereference(event->buffer); - if (!buffer) - goto unlock; - - if (vmf->pgoff && (vmf->flags & FAULT_FLAG_WRITE)) - goto unlock; - - vmf->page = perf_mmap_to_page(buffer, vmf->pgoff); - if (!vmf->page) - goto unlock; - - get_page(vmf->page); - vmf->page->mapping = vma->vm_file->f_mapping; - vmf->page->index = vmf->pgoff; - - ret = 0; -unlock: - rcu_read_unlock(); - - return ret; -} - -static void perf_buffer_free_rcu(struct rcu_head *rcu_head) -{ - struct perf_buffer *buffer; - - buffer = container_of(rcu_head, struct perf_buffer, rcu_head); - perf_buffer_free(buffer); -} - -static struct perf_buffer *perf_buffer_get(struct perf_event *event) -{ - struct perf_buffer *buffer; - - rcu_read_lock(); - buffer = rcu_dereference(event->buffer); - if (buffer) { - if (!atomic_inc_not_zero(&buffer->refcount)) - buffer = NULL; - } - rcu_read_unlock(); - - return buffer; -} - -static void perf_buffer_put(struct perf_buffer *buffer) -{ - if (!atomic_dec_and_test(&buffer->refcount)) - return; - - call_rcu(&buffer->rcu_head, perf_buffer_free_rcu); -} - -static void perf_mmap_open(struct vm_area_struct *vma) -{ - struct perf_event *event = vma->vm_file->private_data; - - atomic_inc(&event->mmap_count); -} - -static void perf_mmap_close(struct vm_area_struct *vma) -{ - struct perf_event *event = vma->vm_file->private_data; - - if (atomic_dec_and_mutex_lock(&event->mmap_count, &event->mmap_mutex)) { - unsigned long size = perf_data_size(event->buffer); - struct user_struct *user = event->mmap_user; - struct perf_buffer *buffer = event->buffer; - - atomic_long_sub((size >> PAGE_SHIFT) + 1, &user->locked_vm); - vma->vm_mm->locked_vm -= event->mmap_locked; - rcu_assign_pointer(event->buffer, NULL); - mutex_unlock(&event->mmap_mutex); - - perf_buffer_put(buffer); - free_uid(user); - } -} - -static const struct vm_operations_struct perf_mmap_vmops = { - .open = perf_mmap_open, - .close = perf_mmap_close, - .fault = perf_mmap_fault, - .page_mkwrite = perf_mmap_fault, -}; - -static int perf_mmap(struct file *file, struct vm_area_struct *vma) -{ - struct perf_event *event = file->private_data; - unsigned long user_locked, user_lock_limit; - struct user_struct *user = current_user(); - unsigned long locked, lock_limit; - struct perf_buffer *buffer; - unsigned long vma_size; - unsigned long nr_pages; - long user_extra, extra; - int ret = 0, flags = 0; - - /* - * Don't allow mmap() of inherited per-task counters. This would - * create a performance issue due to all children writing to the - * same buffer. - */ - if (event->cpu == -1 && event->attr.inherit) - return -EINVAL; - - if (!(vma->vm_flags & VM_SHARED)) - return -EINVAL; - - vma_size = vma->vm_end - vma->vm_start; - nr_pages = (vma_size / PAGE_SIZE) - 1; - - /* - * If we have buffer pages ensure they're a power-of-two number, so we - * can do bitmasks instead of modulo. - */ - if (nr_pages != 0 && !is_power_of_2(nr_pages)) - return -EINVAL; - - if (vma_size != PAGE_SIZE * (1 + nr_pages)) - return -EINVAL; - - if (vma->vm_pgoff != 0) - return -EINVAL; - - WARN_ON_ONCE(event->ctx->parent_ctx); - mutex_lock(&event->mmap_mutex); - if (event->buffer) { - if (event->buffer->nr_pages == nr_pages) - atomic_inc(&event->buffer->refcount); - else - ret = -EINVAL; - goto unlock; - } - - user_extra = nr_pages + 1; - user_lock_limit = sysctl_perf_event_mlock >> (PAGE_SHIFT - 10); - - /* - * Increase the limit linearly with more CPUs: - */ - user_lock_limit *= num_online_cpus(); - - user_locked = atomic_long_read(&user->locked_vm) + user_extra; - - extra = 0; - if (user_locked > user_lock_limit) - extra = user_locked - user_lock_limit; - - lock_limit = rlimit(RLIMIT_MEMLOCK); - lock_limit >>= PAGE_SHIFT; - locked = vma->vm_mm->locked_vm + extra; - - if ((locked > lock_limit) && perf_paranoid_tracepoint_raw() && - !capable(CAP_IPC_LOCK)) { - ret = -EPERM; - goto unlock; - } - - WARN_ON(event->buffer); - - if (vma->vm_flags & VM_WRITE) - flags |= PERF_BUFFER_WRITABLE; - - buffer = perf_buffer_alloc(nr_pages, event->attr.wakeup_watermark, - event->cpu, flags); - if (!buffer) { - ret = -ENOMEM; - goto unlock; - } - rcu_assign_pointer(event->buffer, buffer); - - atomic_long_add(user_extra, &user->locked_vm); - event->mmap_locked = extra; - event->mmap_user = get_current_user(); - vma->vm_mm->locked_vm += event->mmap_locked; - -unlock: - if (!ret) - atomic_inc(&event->mmap_count); - mutex_unlock(&event->mmap_mutex); - - vma->vm_flags |= VM_RESERVED; - vma->vm_ops = &perf_mmap_vmops; - - return ret; -} - -static int perf_fasync(int fd, struct file *filp, int on) -{ - struct inode *inode = filp->f_path.dentry->d_inode; - struct perf_event *event = filp->private_data; - int retval; - - mutex_lock(&inode->i_mutex); - retval = fasync_helper(fd, filp, on, &event->fasync); - mutex_unlock(&inode->i_mutex); - - if (retval < 0) - return retval; - - return 0; -} - -static const struct file_operations perf_fops = { - .llseek = no_llseek, - .release = perf_release, - .read = perf_read, - .poll = perf_poll, - .unlocked_ioctl = perf_ioctl, - .compat_ioctl = perf_ioctl, - .mmap = perf_mmap, - .fasync = perf_fasync, -}; - -/* - * Perf event wakeup - * - * If there's data, ensure we set the poll() state and publish everything - * to user-space before waking everybody up. - */ - -void perf_event_wakeup(struct perf_event *event) -{ - wake_up_all(&event->waitq); - - if (event->pending_kill) { - kill_fasync(&event->fasync, SIGIO, event->pending_kill); - event->pending_kill = 0; - } -} - -static void perf_pending_event(struct irq_work *entry) -{ - struct perf_event *event = container_of(entry, - struct perf_event, pending); - - if (event->pending_disable) { - event->pending_disable = 0; - __perf_event_disable(event); - } - - if (event->pending_wakeup) { - event->pending_wakeup = 0; - perf_event_wakeup(event); - } -} - -/* - * We assume there is only KVM supporting the callbacks. - * Later on, we might change it to a list if there is - * another virtualization implementation supporting the callbacks. - */ -struct perf_guest_info_callbacks *perf_guest_cbs; - -int perf_register_guest_info_callbacks(struct perf_guest_info_callbacks *cbs) -{ - perf_guest_cbs = cbs; - return 0; -} -EXPORT_SYMBOL_GPL(perf_register_guest_info_callbacks); - -int perf_unregister_guest_info_callbacks(struct perf_guest_info_callbacks *cbs) -{ - perf_guest_cbs = NULL; - return 0; -} -EXPORT_SYMBOL_GPL(perf_unregister_guest_info_callbacks); - -/* - * Output - */ -static bool perf_output_space(struct perf_buffer *buffer, unsigned long tail, - unsigned long offset, unsigned long head) -{ - unsigned long mask; - - if (!buffer->writable) - return true; - - mask = perf_data_size(buffer) - 1; - - offset = (offset - tail) & mask; - head = (head - tail) & mask; - - if ((int)(head - offset) < 0) - return false; - - return true; -} - -static void perf_output_wakeup(struct perf_output_handle *handle) -{ - atomic_set(&handle->buffer->poll, POLL_IN); - - if (handle->nmi) { - handle->event->pending_wakeup = 1; - irq_work_queue(&handle->event->pending); - } else - perf_event_wakeup(handle->event); -} - -/* - * We need to ensure a later event_id doesn't publish a head when a former - * event isn't done writing. However since we need to deal with NMIs we - * cannot fully serialize things. - * - * We only publish the head (and generate a wakeup) when the outer-most - * event completes. - */ -static void perf_output_get_handle(struct perf_output_handle *handle) -{ - struct perf_buffer *buffer = handle->buffer; - - preempt_disable(); - local_inc(&buffer->nest); - handle->wakeup = local_read(&buffer->wakeup); -} - -static void perf_output_put_handle(struct perf_output_handle *handle) -{ - struct perf_buffer *buffer = handle->buffer; - unsigned long head; - -again: - head = local_read(&buffer->head); - - /* - * IRQ/NMI can happen here, which means we can miss a head update. - */ - - if (!local_dec_and_test(&buffer->nest)) - goto out; - - /* - * Publish the known good head. Rely on the full barrier implied - * by atomic_dec_and_test() order the buffer->head read and this - * write. - */ - buffer->user_page->data_head = head; - - /* - * Now check if we missed an update, rely on the (compiler) - * barrier in atomic_dec_and_test() to re-read buffer->head. - */ - if (unlikely(head != local_read(&buffer->head))) { - local_inc(&buffer->nest); - goto again; - } - - if (handle->wakeup != local_read(&buffer->wakeup)) - perf_output_wakeup(handle); - -out: - preempt_enable(); -} - -__always_inline void perf_output_copy(struct perf_output_handle *handle, - const void *buf, unsigned int len) -{ - do { - unsigned long size = min_t(unsigned long, handle->size, len); - - memcpy(handle->addr, buf, size); - - len -= size; - handle->addr += size; - buf += size; - handle->size -= size; - if (!handle->size) { - struct perf_buffer *buffer = handle->buffer; - - handle->page++; - handle->page &= buffer->nr_pages - 1; - handle->addr = buffer->data_pages[handle->page]; - handle->size = PAGE_SIZE << page_order(buffer); - } - } while (len); -} - -static void __perf_event_header__init_id(struct perf_event_header *header, - struct perf_sample_data *data, - struct perf_event *event) -{ - u64 sample_type = event->attr.sample_type; - - data->type = sample_type; - header->size += event->id_header_size; - - if (sample_type & PERF_SAMPLE_TID) { - /* namespace issues */ - data->tid_entry.pid = perf_event_pid(event, current); - data->tid_entry.tid = perf_event_tid(event, current); - } - - if (sample_type & PERF_SAMPLE_TIME) - data->time = perf_clock(); - - if (sample_type & PERF_SAMPLE_ID) - data->id = primary_event_id(event); - - if (sample_type & PERF_SAMPLE_STREAM_ID) - data->stream_id = event->id; - - if (sample_type & PERF_SAMPLE_CPU) { - data->cpu_entry.cpu = raw_smp_processor_id(); - data->cpu_entry.reserved = 0; - } -} - -static void perf_event_header__init_id(struct perf_event_header *header, - struct perf_sample_data *data, - struct perf_event *event) -{ - if (event->attr.sample_id_all) - __perf_event_header__init_id(header, data, event); -} - -static void __perf_event__output_id_sample(struct perf_output_handle *handle, - struct perf_sample_data *data) -{ - u64 sample_type = data->type; - - if (sample_type & PERF_SAMPLE_TID) - perf_output_put(handle, data->tid_entry); - - if (sample_type & PERF_SAMPLE_TIME) - perf_output_put(handle, data->time); - - if (sample_type & PERF_SAMPLE_ID) - perf_output_put(handle, data->id); - - if (sample_type & PERF_SAMPLE_STREAM_ID) - perf_output_put(handle, data->stream_id); - - if (sample_type & PERF_SAMPLE_CPU) - perf_output_put(handle, data->cpu_entry); -} - -static void perf_event__output_id_sample(struct perf_event *event, - struct perf_output_handle *handle, - struct perf_sample_data *sample) -{ - if (event->attr.sample_id_all) - __perf_event__output_id_sample(handle, sample); -} - -int perf_output_begin(struct perf_output_handle *handle, - struct perf_event *event, unsigned int size, - int nmi, int sample) -{ - struct perf_buffer *buffer; - unsigned long tail, offset, head; - int have_lost; - struct perf_sample_data sample_data; - struct { - struct perf_event_header header; - u64 id; - u64 lost; - } lost_event; - - rcu_read_lock(); - /* - * For inherited events we send all the output towards the parent. - */ - if (event->parent) - event = event->parent; - - buffer = rcu_dereference(event->buffer); - if (!buffer) - goto out; - - handle->buffer = buffer; - handle->event = event; - handle->nmi = nmi; - handle->sample = sample; - - if (!buffer->nr_pages) - goto out; - - have_lost = local_read(&buffer->lost); - if (have_lost) { - lost_event.header.size = sizeof(lost_event); - perf_event_header__init_id(&lost_event.header, &sample_data, - event); - size += lost_event.header.size; - } - - perf_output_get_handle(handle); - - do { - /* - * Userspace could choose to issue a mb() before updating the - * tail pointer. So that all reads will be completed before the - * write is issued. - */ - tail = ACCESS_ONCE(buffer->user_page->data_tail); - smp_rmb(); - offset = head = local_read(&buffer->head); - head += size; - if (unlikely(!perf_output_space(buffer, tail, offset, head))) - goto fail; - } while (local_cmpxchg(&buffer->head, offset, head) != offset); - - if (head - local_read(&buffer->wakeup) > buffer->watermark) - local_add(buffer->watermark, &buffer->wakeup); - - handle->page = offset >> (PAGE_SHIFT + page_order(buffer)); - handle->page &= buffer->nr_pages - 1; - handle->size = offset & ((PAGE_SIZE << page_order(buffer)) - 1); - handle->addr = buffer->data_pages[handle->page]; - handle->addr += handle->size; - handle->size = (PAGE_SIZE << page_order(buffer)) - handle->size; - - if (have_lost) { - lost_event.header.type = PERF_RECORD_LOST; - lost_event.header.misc = 0; - lost_event.id = event->id; - lost_event.lost = local_xchg(&buffer->lost, 0); - - perf_output_put(handle, lost_event); - perf_event__output_id_sample(event, handle, &sample_data); - } - - return 0; - -fail: - local_inc(&buffer->lost); - perf_output_put_handle(handle); -out: - rcu_read_unlock(); - - return -ENOSPC; -} - -void perf_output_end(struct perf_output_handle *handle) -{ - struct perf_event *event = handle->event; - struct perf_buffer *buffer = handle->buffer; - - int wakeup_events = event->attr.wakeup_events; - - if (handle->sample && wakeup_events) { - int events = local_inc_return(&buffer->events); - if (events >= wakeup_events) { - local_sub(wakeup_events, &buffer->events); - local_inc(&buffer->wakeup); - } - } - - perf_output_put_handle(handle); - rcu_read_unlock(); -} - -static void perf_output_read_one(struct perf_output_handle *handle, - struct perf_event *event, - u64 enabled, u64 running) -{ - u64 read_format = event->attr.read_format; - u64 values[4]; - int n = 0; - - values[n++] = perf_event_count(event); - if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED) { - values[n++] = enabled + - atomic64_read(&event->child_total_time_enabled); - } - if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING) { - values[n++] = running + - atomic64_read(&event->child_total_time_running); - } - if (read_format & PERF_FORMAT_ID) - values[n++] = primary_event_id(event); - - perf_output_copy(handle, values, n * sizeof(u64)); -} - -/* - * XXX PERF_FORMAT_GROUP vs inherited events seems difficult. - */ -static void perf_output_read_group(struct perf_output_handle *handle, - struct perf_event *event, - u64 enabled, u64 running) -{ - struct perf_event *leader = event->group_leader, *sub; - u64 read_format = event->attr.read_format; - u64 values[5]; - int n = 0; - - values[n++] = 1 + leader->nr_siblings; - - if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED) - values[n++] = enabled; - - if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING) - values[n++] = running; - - if (leader != event) - leader->pmu->read(leader); - - values[n++] = perf_event_count(leader); - if (read_format & PERF_FORMAT_ID) - values[n++] = primary_event_id(leader); - - perf_output_copy(handle, values, n * sizeof(u64)); - - list_for_each_entry(sub, &leader->sibling_list, group_entry) { - n = 0; - - if (sub != event) - sub->pmu->read(sub); - - values[n++] = perf_event_count(sub); - if (read_format & PERF_FORMAT_ID) - values[n++] = primary_event_id(sub); - - perf_output_copy(handle, values, n * sizeof(u64)); - } -} - -#define PERF_FORMAT_TOTAL_TIMES (PERF_FORMAT_TOTAL_TIME_ENABLED|\ - PERF_FORMAT_TOTAL_TIME_RUNNING) - -static void perf_output_read(struct perf_output_handle *handle, - struct perf_event *event) -{ - u64 enabled = 0, running = 0, now, ctx_time; - u64 read_format = event->attr.read_format; - - /* - * compute total_time_enabled, total_time_running - * based on snapshot values taken when the event - * was last scheduled in. - * - * we cannot simply called update_context_time() - * because of locking issue as we are called in - * NMI context - */ - if (read_format & PERF_FORMAT_TOTAL_TIMES) { - now = perf_clock(); - ctx_time = event->shadow_ctx_time + now; - enabled = ctx_time - event->tstamp_enabled; - running = ctx_time - event->tstamp_running; - } - - if (event->attr.read_format & PERF_FORMAT_GROUP) - perf_output_read_group(handle, event, enabled, running); - else - perf_output_read_one(handle, event, enabled, running); -} - -void perf_output_sample(struct perf_output_handle *handle, - struct perf_event_header *header, - struct perf_sample_data *data, - struct perf_event *event) -{ - u64 sample_type = data->type; - - perf_output_put(handle, *header); - - if (sample_type & PERF_SAMPLE_IP) - perf_output_put(handle, data->ip); - - if (sample_type & PERF_SAMPLE_TID) - perf_output_put(handle, data->tid_entry); - - if (sample_type & PERF_SAMPLE_TIME) - perf_output_put(handle, data->time); - - if (sample_type & PERF_SAMPLE_ADDR) - perf_output_put(handle, data->addr); - - if (sample_type & PERF_SAMPLE_ID) - perf_output_put(handle, data->id); - - if (sample_type & PERF_SAMPLE_STREAM_ID) - perf_output_put(handle, data->stream_id); - - if (sample_type & PERF_SAMPLE_CPU) - perf_output_put(handle, data->cpu_entry); - - if (sample_type & PERF_SAMPLE_PERIOD) - perf_output_put(handle, data->period); - - if (sample_type & PERF_SAMPLE_READ) - perf_output_read(handle, event); - - if (sample_type & PERF_SAMPLE_CALLCHAIN) { - if (data->callchain) { - int size = 1; - - if (data->callchain) - size += data->callchain->nr; - - size *= sizeof(u64); - - perf_output_copy(handle, data->callchain, size); - } else { - u64 nr = 0; - perf_output_put(handle, nr); - } - } - - if (sample_type & PERF_SAMPLE_RAW) { - if (data->raw) { - perf_output_put(handle, data->raw->size); - perf_output_copy(handle, data->raw->data, - data->raw->size); - } else { - struct { - u32 size; - u32 data; - } raw = { - .size = sizeof(u32), - .data = 0, - }; - perf_output_put(handle, raw); - } - } -} - -void perf_prepare_sample(struct perf_event_header *header, - struct perf_sample_data *data, - struct perf_event *event, - struct pt_regs *regs) -{ - u64 sample_type = event->attr.sample_type; - - header->type = PERF_RECORD_SAMPLE; - header->size = sizeof(*header) + event->header_size; - - header->misc = 0; - header->misc |= perf_misc_flags(regs); - - __perf_event_header__init_id(header, data, event); - - if (sample_type & PERF_SAMPLE_IP) - data->ip = perf_instruction_pointer(regs); - - if (sample_type & PERF_SAMPLE_CALLCHAIN) { - int size = 1; - - data->callchain = perf_callchain(regs); - - if (data->callchain) - size += data->callchain->nr; - - header->size += size * sizeof(u64); - } - - if (sample_type & PERF_SAMPLE_RAW) { - int size = sizeof(u32); - - if (data->raw) - size += data->raw->size; - else - size += sizeof(u32); - - WARN_ON_ONCE(size & (sizeof(u64)-1)); - header->size += size; - } -} - -static void perf_event_output(struct perf_event *event, int nmi, - struct perf_sample_data *data, - struct pt_regs *regs) -{ - struct perf_output_handle handle; - struct perf_event_header header; - - /* protect the callchain buffers */ - rcu_read_lock(); - - perf_prepare_sample(&header, data, event, regs); - - if (perf_output_begin(&handle, event, header.size, nmi, 1)) - goto exit; - - perf_output_sample(&handle, &header, data, event); - - perf_output_end(&handle); - -exit: - rcu_read_unlock(); -} - -/* - * read event_id - */ - -struct perf_read_event { - struct perf_event_header header; - - u32 pid; - u32 tid; -}; - -static void -perf_event_read_event(struct perf_event *event, - struct task_struct *task) -{ - struct perf_output_handle handle; - struct perf_sample_data sample; - struct perf_read_event read_event = { - .header = { - .type = PERF_RECORD_READ, - .misc = 0, - .size = sizeof(read_event) + event->read_size, - }, - .pid = perf_event_pid(event, task), - .tid = perf_event_tid(event, task), - }; - int ret; - - perf_event_header__init_id(&read_event.header, &sample, event); - ret = perf_output_begin(&handle, event, read_event.header.size, 0, 0); - if (ret) - return; - - perf_output_put(&handle, read_event); - perf_output_read(&handle, event); - perf_event__output_id_sample(event, &handle, &sample); - - perf_output_end(&handle); -} - -/* - * task tracking -- fork/exit - * - * enabled by: attr.comm | attr.mmap | attr.mmap_data | attr.task - */ - -struct perf_task_event { - struct task_struct *task; - struct perf_event_context *task_ctx; - - struct { - struct perf_event_header header; - - u32 pid; - u32 ppid; - u32 tid; - u32 ptid; - u64 time; - } event_id; -}; - -static void perf_event_task_output(struct perf_event *event, - struct perf_task_event *task_event) -{ - struct perf_output_handle handle; - struct perf_sample_data sample; - struct task_struct *task = task_event->task; - int ret, size = task_event->event_id.header.size; - - perf_event_header__init_id(&task_event->event_id.header, &sample, event); - - ret = perf_output_begin(&handle, event, - task_event->event_id.header.size, 0, 0); - if (ret) - goto out; - - task_event->event_id.pid = perf_event_pid(event, task); - task_event->event_id.ppid = perf_event_pid(event, current); - - task_event->event_id.tid = perf_event_tid(event, task); - task_event->event_id.ptid = perf_event_tid(event, current); - - perf_output_put(&handle, task_event->event_id); - - perf_event__output_id_sample(event, &handle, &sample); - - perf_output_end(&handle); -out: - task_event->event_id.header.size = size; -} - -static int perf_event_task_match(struct perf_event *event) -{ - if (event->state < PERF_EVENT_STATE_INACTIVE) - return 0; - - if (!event_filter_match(event)) - return 0; - - if (event->attr.comm || event->attr.mmap || - event->attr.mmap_data || event->attr.task) - return 1; - - return 0; -} - -static void perf_event_task_ctx(struct perf_event_context *ctx, - struct perf_task_event *task_event) -{ - struct perf_event *event; - - list_for_each_entry_rcu(event, &ctx->event_list, event_entry) { - if (perf_event_task_match(event)) - perf_event_task_output(event, task_event); - } -} - -static void perf_event_task_event(struct perf_task_event *task_event) -{ - struct perf_cpu_context *cpuctx; - struct perf_event_context *ctx; - struct pmu *pmu; - int ctxn; - - rcu_read_lock(); - list_for_each_entry_rcu(pmu, &pmus, entry) { - cpuctx = get_cpu_ptr(pmu->pmu_cpu_context); - if (cpuctx->active_pmu != pmu) - goto next; - perf_event_task_ctx(&cpuctx->ctx, task_event); - - ctx = task_event->task_ctx; - if (!ctx) { - ctxn = pmu->task_ctx_nr; - if (ctxn < 0) - goto next; - ctx = rcu_dereference(current->perf_event_ctxp[ctxn]); - } - if (ctx) - perf_event_task_ctx(ctx, task_event); -next: - put_cpu_ptr(pmu->pmu_cpu_context); - } - rcu_read_unlock(); -} - -static void perf_event_task(struct task_struct *task, - struct perf_event_context *task_ctx, - int new) -{ - struct perf_task_event task_event; - - if (!atomic_read(&nr_comm_events) && - !atomic_read(&nr_mmap_events) && - !atomic_read(&nr_task_events)) - return; - - task_event = (struct perf_task_event){ - .task = task, - .task_ctx = task_ctx, - .event_id = { - .header = { - .type = new ? PERF_RECORD_FORK : PERF_RECORD_EXIT, - .misc = 0, - .size = sizeof(task_event.event_id), - }, - /* .pid */ - /* .ppid */ - /* .tid */ - /* .ptid */ - .time = perf_clock(), - }, - }; - - perf_event_task_event(&task_event); -} - -void perf_event_fork(struct task_struct *task) -{ - perf_event_task(task, NULL, 1); -} - -/* - * comm tracking - */ - -struct perf_comm_event { - struct task_struct *task; - char *comm; - int comm_size; - - struct { - struct perf_event_header header; - - u32 pid; - u32 tid; - } event_id; -}; - -static void perf_event_comm_output(struct perf_event *event, - struct perf_comm_event *comm_event) -{ - struct perf_output_handle handle; - struct perf_sample_data sample; - int size = comm_event->event_id.header.size; - int ret; - - perf_event_header__init_id(&comm_event->event_id.header, &sample, event); - ret = perf_output_begin(&handle, event, - comm_event->event_id.header.size, 0, 0); - - if (ret) - goto out; - - comm_event->event_id.pid = perf_event_pid(event, comm_event->task); - comm_event->event_id.tid = perf_event_tid(event, comm_event->task); - - perf_output_put(&handle, comm_event->event_id); - perf_output_copy(&handle, comm_event->comm, - comm_event->comm_size); - - perf_event__output_id_sample(event, &handle, &sample); - - perf_output_end(&handle); -out: - comm_event->event_id.header.size = size; -} - -static int perf_event_comm_match(struct perf_event *event) -{ - if (event->state < PERF_EVENT_STATE_INACTIVE) - return 0; - - if (!event_filter_match(event)) - return 0; - - if (event->attr.comm) - return 1; - - return 0; -} - -static void perf_event_comm_ctx(struct perf_event_context *ctx, - struct perf_comm_event *comm_event) -{ - struct perf_event *event; - - list_for_each_entry_rcu(event, &ctx->event_list, event_entry) { - if (perf_event_comm_match(event)) - perf_event_comm_output(event, comm_event); - } -} - -static void perf_event_comm_event(struct perf_comm_event *comm_event) -{ - struct perf_cpu_context *cpuctx; - struct perf_event_context *ctx; - char comm[TASK_COMM_LEN]; - unsigned int size; - struct pmu *pmu; - int ctxn; - - memset(comm, 0, sizeof(comm)); - strlcpy(comm, comm_event->task->comm, sizeof(comm)); - size = ALIGN(strlen(comm)+1, sizeof(u64)); - - comm_event->comm = comm; - comm_event->comm_size = size; - - comm_event->event_id.header.size = sizeof(comm_event->event_id) + size; - rcu_read_lock(); - list_for_each_entry_rcu(pmu, &pmus, entry) { - cpuctx = get_cpu_ptr(pmu->pmu_cpu_context); - if (cpuctx->active_pmu != pmu) - goto next; - perf_event_comm_ctx(&cpuctx->ctx, comm_event); - - ctxn = pmu->task_ctx_nr; - if (ctxn < 0) - goto next; - - ctx = rcu_dereference(current->perf_event_ctxp[ctxn]); - if (ctx) - perf_event_comm_ctx(ctx, comm_event); -next: - put_cpu_ptr(pmu->pmu_cpu_context); - } - rcu_read_unlock(); -} - -void perf_event_comm(struct task_struct *task) -{ - struct perf_comm_event comm_event; - struct perf_event_context *ctx; - int ctxn; - - for_each_task_context_nr(ctxn) { - ctx = task->perf_event_ctxp[ctxn]; - if (!ctx) - continue; - - perf_event_enable_on_exec(ctx); - } - - if (!atomic_read(&nr_comm_events)) - return; - - comm_event = (struct perf_comm_event){ - .task = task, - /* .comm */ - /* .comm_size */ - .event_id = { - .header = { - .type = PERF_RECORD_COMM, - .misc = 0, - /* .size */ - }, - /* .pid */ - /* .tid */ - }, - }; - - perf_event_comm_event(&comm_event); -} - -/* - * mmap tracking - */ - -struct perf_mmap_event { - struct vm_area_struct *vma; - - const char *file_name; - int file_size; - - struct { - struct perf_event_header header; - - u32 pid; - u32 tid; - u64 start; - u64 len; - u64 pgoff; - } event_id; -}; - -static void perf_event_mmap_output(struct perf_event *event, - struct perf_mmap_event *mmap_event) -{ - struct perf_output_handle handle; - struct perf_sample_data sample; - int size = mmap_event->event_id.header.size; - int ret; - - perf_event_header__init_id(&mmap_event->event_id.header, &sample, event); - ret = perf_output_begin(&handle, event, - mmap_event->event_id.header.size, 0, 0); - if (ret) - goto out; - - mmap_event->event_id.pid = perf_event_pid(event, current); - mmap_event->event_id.tid = perf_event_tid(event, current); - - perf_output_put(&handle, mmap_event->event_id); - perf_output_copy(&handle, mmap_event->file_name, - mmap_event->file_size); - - perf_event__output_id_sample(event, &handle, &sample); - - perf_output_end(&handle); -out: - mmap_event->event_id.header.size = size; -} - -static int perf_event_mmap_match(struct perf_event *event, - struct perf_mmap_event *mmap_event, - int executable) -{ - if (event->state < PERF_EVENT_STATE_INACTIVE) - return 0; - - if (!event_filter_match(event)) - return 0; - - if ((!executable && event->attr.mmap_data) || - (executable && event->attr.mmap)) - return 1; - - return 0; -} - -static void perf_event_mmap_ctx(struct perf_event_context *ctx, - struct perf_mmap_event *mmap_event, - int executable) -{ - struct perf_event *event; - - list_for_each_entry_rcu(event, &ctx->event_list, event_entry) { - if (perf_event_mmap_match(event, mmap_event, executable)) - perf_event_mmap_output(event, mmap_event); - } -} - -static void perf_event_mmap_event(struct perf_mmap_event *mmap_event) -{ - struct perf_cpu_context *cpuctx; - struct perf_event_context *ctx; - struct vm_area_struct *vma = mmap_event->vma; - struct file *file = vma->vm_file; - unsigned int size; - char tmp[16]; - char *buf = NULL; - const char *name; - struct pmu *pmu; - int ctxn; - - memset(tmp, 0, sizeof(tmp)); - - if (file) { - /* - * d_path works from the end of the buffer backwards, so we - * need to add enough zero bytes after the string to handle - * the 64bit alignment we do later. - */ - buf = kzalloc(PATH_MAX + sizeof(u64), GFP_KERNEL); - if (!buf) { - name = strncpy(tmp, "//enomem", sizeof(tmp)); - goto got_name; - } - name = d_path(&file->f_path, buf, PATH_MAX); - if (IS_ERR(name)) { - name = strncpy(tmp, "//toolong", sizeof(tmp)); - goto got_name; - } - } else { - if (arch_vma_name(mmap_event->vma)) { - name = strncpy(tmp, arch_vma_name(mmap_event->vma), - sizeof(tmp)); - goto got_name; - } - - if (!vma->vm_mm) { - name = strncpy(tmp, "[vdso]", sizeof(tmp)); - goto got_name; - } else if (vma->vm_start <= vma->vm_mm->start_brk && - vma->vm_end >= vma->vm_mm->brk) { - name = strncpy(tmp, "[heap]", sizeof(tmp)); - goto got_name; - } else if (vma->vm_start <= vma->vm_mm->start_stack && - vma->vm_end >= vma->vm_mm->start_stack) { - name = strncpy(tmp, "[stack]", sizeof(tmp)); - goto got_name; - } - - name = strncpy(tmp, "//anon", sizeof(tmp)); - goto got_name; - } - -got_name: - size = ALIGN(strlen(name)+1, sizeof(u64)); - - mmap_event->file_name = name; - mmap_event->file_size = size; - - mmap_event->event_id.header.size = sizeof(mmap_event->event_id) + size; - - rcu_read_lock(); - list_for_each_entry_rcu(pmu, &pmus, entry) { - cpuctx = get_cpu_ptr(pmu->pmu_cpu_context); - if (cpuctx->active_pmu != pmu) - goto next; - perf_event_mmap_ctx(&cpuctx->ctx, mmap_event, - vma->vm_flags & VM_EXEC); - - ctxn = pmu->task_ctx_nr; - if (ctxn < 0) - goto next; - - ctx = rcu_dereference(current->perf_event_ctxp[ctxn]); - if (ctx) { - perf_event_mmap_ctx(ctx, mmap_event, - vma->vm_flags & VM_EXEC); - } -next: - put_cpu_ptr(pmu->pmu_cpu_context); - } - rcu_read_unlock(); - - kfree(buf); -} - -void perf_event_mmap(struct vm_area_struct *vma) -{ - struct perf_mmap_event mmap_event; - - if (!atomic_read(&nr_mmap_events)) - return; - - mmap_event = (struct perf_mmap_event){ - .vma = vma, - /* .file_name */ - /* .file_size */ - .event_id = { - .header = { - .type = PERF_RECORD_MMAP, - .misc = PERF_RECORD_MISC_USER, - /* .size */ - }, - /* .pid */ - /* .tid */ - .start = vma->vm_start, - .len = vma->vm_end - vma->vm_start, - .pgoff = (u64)vma->vm_pgoff << PAGE_SHIFT, - }, - }; - - perf_event_mmap_event(&mmap_event); -} - -/* - * IRQ throttle logging - */ - -static void perf_log_throttle(struct perf_event *event, int enable) -{ - struct perf_output_handle handle; - struct perf_sample_data sample; - int ret; - - struct { - struct perf_event_header header; - u64 time; - u64 id; - u64 stream_id; - } throttle_event = { - .header = { - .type = PERF_RECORD_THROTTLE, - .misc = 0, - .size = sizeof(throttle_event), - }, - .time = perf_clock(), - .id = primary_event_id(event), - .stream_id = event->id, - }; - - if (enable) - throttle_event.header.type = PERF_RECORD_UNTHROTTLE; - - perf_event_header__init_id(&throttle_event.header, &sample, event); - - ret = perf_output_begin(&handle, event, - throttle_event.header.size, 1, 0); - if (ret) - return; - - perf_output_put(&handle, throttle_event); - perf_event__output_id_sample(event, &handle, &sample); - perf_output_end(&handle); -} - -/* - * Generic event overflow handling, sampling. - */ - -static int __perf_event_overflow(struct perf_event *event, int nmi, - int throttle, struct perf_sample_data *data, - struct pt_regs *regs) -{ - int events = atomic_read(&event->event_limit); - struct hw_perf_event *hwc = &event->hw; - int ret = 0; - - /* - * Non-sampling counters might still use the PMI to fold short - * hardware counters, ignore those. - */ - if (unlikely(!is_sampling_event(event))) - return 0; - - if (unlikely(hwc->interrupts >= max_samples_per_tick)) { - if (throttle) { - hwc->interrupts = MAX_INTERRUPTS; - perf_log_throttle(event, 0); - ret = 1; - } - } else - hwc->interrupts++; - - if (event->attr.freq) { - u64 now = perf_clock(); - s64 delta = now - hwc->freq_time_stamp; - - hwc->freq_time_stamp = now; - - if (delta > 0 && delta < 2*TICK_NSEC) - perf_adjust_period(event, delta, hwc->last_period); - } - - /* - * XXX event_limit might not quite work as expected on inherited - * events - */ - - event->pending_kill = POLL_IN; - if (events && atomic_dec_and_test(&event->event_limit)) { - ret = 1; - event->pending_kill = POLL_HUP; - if (nmi) { - event->pending_disable = 1; - irq_work_queue(&event->pending); - } else - perf_event_disable(event); - } - - if (event->overflow_handler) - event->overflow_handler(event, nmi, data, regs); - else - perf_event_output(event, nmi, data, regs); - - return ret; -} - -int perf_event_overflow(struct perf_event *event, int nmi, - struct perf_sample_data *data, - struct pt_regs *regs) -{ - return __perf_event_overflow(event, nmi, 1, data, regs); -} - -/* - * Generic software event infrastructure - */ - -struct swevent_htable { - struct swevent_hlist *swevent_hlist; - struct mutex hlist_mutex; - int hlist_refcount; - - /* Recursion avoidance in each contexts */ - int recursion[PERF_NR_CONTEXTS]; -}; - -static DEFINE_PER_CPU(struct swevent_htable, swevent_htable); - -/* - * We directly increment event->count and keep a second value in - * event->hw.period_left to count intervals. This period event - * is kept in the range [-sample_period, 0] so that we can use the - * sign as trigger. - */ - -static u64 perf_swevent_set_period(struct perf_event *event) -{ - struct hw_perf_event *hwc = &event->hw; - u64 period = hwc->last_period; - u64 nr, offset; - s64 old, val; - - hwc->last_period = hwc->sample_period; - -again: - old = val = local64_read(&hwc->period_left); - if (val < 0) - return 0; - - nr = div64_u64(period + val, period); - offset = nr * period; - val -= offset; - if (local64_cmpxchg(&hwc->period_left, old, val) != old) - goto again; - - return nr; -} - -static void perf_swevent_overflow(struct perf_event *event, u64 overflow, - int nmi, struct perf_sample_data *data, - struct pt_regs *regs) -{ - struct hw_perf_event *hwc = &event->hw; - int throttle = 0; - - data->period = event->hw.last_period; - if (!overflow) - overflow = perf_swevent_set_period(event); - - if (hwc->interrupts == MAX_INTERRUPTS) - return; - - for (; overflow; overflow--) { - if (__perf_event_overflow(event, nmi, throttle, - data, regs)) { - /* - * We inhibit the overflow from happening when - * hwc->interrupts == MAX_INTERRUPTS. - */ - break; - } - throttle = 1; - } -} - -static void perf_swevent_event(struct perf_event *event, u64 nr, - int nmi, struct perf_sample_data *data, - struct pt_regs *regs) -{ - struct hw_perf_event *hwc = &event->hw; - - local64_add(nr, &event->count); - - if (!regs) - return; - - if (!is_sampling_event(event)) - return; - - if (nr == 1 && hwc->sample_period == 1 && !event->attr.freq) - return perf_swevent_overflow(event, 1, nmi, data, regs); - - if (local64_add_negative(nr, &hwc->period_left)) - return; - - perf_swevent_overflow(event, 0, nmi, data, regs); -} - -static int perf_exclude_event(struct perf_event *event, - struct pt_regs *regs) -{ - if (event->hw.state & PERF_HES_STOPPED) - return 1; - - if (regs) { - if (event->attr.exclude_user && user_mode(regs)) - return 1; - - if (event->attr.exclude_kernel && !user_mode(regs)) - return 1; - } - - return 0; -} - -static int perf_swevent_match(struct perf_event *event, - enum perf_type_id type, - u32 event_id, - struct perf_sample_data *data, - struct pt_regs *regs) -{ - if (event->attr.type != type) - return 0; - - if (event->attr.config != event_id) - return 0; - - if (perf_exclude_event(event, regs)) - return 0; - - return 1; -} - -static inline u64 swevent_hash(u64 type, u32 event_id) -{ - u64 val = event_id | (type << 32); - - return hash_64(val, SWEVENT_HLIST_BITS); -} - -static inline struct hlist_head * -__find_swevent_head(struct swevent_hlist *hlist, u64 type, u32 event_id) -{ - u64 hash = swevent_hash(type, event_id); - - return &hlist->heads[hash]; -} - -/* For the read side: events when they trigger */ -static inline struct hlist_head * -find_swevent_head_rcu(struct swevent_htable *swhash, u64 type, u32 event_id) -{ - struct swevent_hlist *hlist; - - hlist = rcu_dereference(swhash->swevent_hlist); - if (!hlist) - return NULL; - - return __find_swevent_head(hlist, type, event_id); -} - -/* For the event head insertion and removal in the hlist */ -static inline struct hlist_head * -find_swevent_head(struct swevent_htable *swhash, struct perf_event *event) -{ - struct swevent_hlist *hlist; - u32 event_id = event->attr.config; - u64 type = event->attr.type; - - /* - * Event scheduling is always serialized against hlist allocation - * and release. Which makes the protected version suitable here. - * The context lock guarantees that. - */ - hlist = rcu_dereference_protected(swhash->swevent_hlist, - lockdep_is_held(&event->ctx->lock)); - if (!hlist) - return NULL; - - return __find_swevent_head(hlist, type, event_id); -} - -static void do_perf_sw_event(enum perf_type_id type, u32 event_id, - u64 nr, int nmi, - struct perf_sample_data *data, - struct pt_regs *regs) -{ - struct swevent_htable *swhash = &__get_cpu_var(swevent_htable); - struct perf_event *event; - struct hlist_node *node; - struct hlist_head *head; - - rcu_read_lock(); - head = find_swevent_head_rcu(swhash, type, event_id); - if (!head) - goto end; - - hlist_for_each_entry_rcu(event, node, head, hlist_entry) { - if (perf_swevent_match(event, type, event_id, data, regs)) - perf_swevent_event(event, nr, nmi, data, regs); - } -end: - rcu_read_unlock(); -} - -int perf_swevent_get_recursion_context(void) -{ - struct swevent_htable *swhash = &__get_cpu_var(swevent_htable); - - return get_recursion_context(swhash->recursion); -} -EXPORT_SYMBOL_GPL(perf_swevent_get_recursion_context); - -inline void perf_swevent_put_recursion_context(int rctx) -{ - struct swevent_htable *swhash = &__get_cpu_var(swevent_htable); - - put_recursion_context(swhash->recursion, rctx); -} - -void __perf_sw_event(u32 event_id, u64 nr, int nmi, - struct pt_regs *regs, u64 addr) -{ - struct perf_sample_data data; - int rctx; - - preempt_disable_notrace(); - rctx = perf_swevent_get_recursion_context(); - if (rctx < 0) - return; - - perf_sample_data_init(&data, addr); - - do_perf_sw_event(PERF_TYPE_SOFTWARE, event_id, nr, nmi, &data, regs); - - perf_swevent_put_recursion_context(rctx); - preempt_enable_notrace(); -} - -static void perf_swevent_read(struct perf_event *event) -{ -} - -static int perf_swevent_add(struct perf_event *event, int flags) -{ - struct swevent_htable *swhash = &__get_cpu_var(swevent_htable); - struct hw_perf_event *hwc = &event->hw; - struct hlist_head *head; - - if (is_sampling_event(event)) { - hwc->last_period = hwc->sample_period; - perf_swevent_set_period(event); - } - - hwc->state = !(flags & PERF_EF_START); - - head = find_swevent_head(swhash, event); - if (WARN_ON_ONCE(!head)) - return -EINVAL; - - hlist_add_head_rcu(&event->hlist_entry, head); - - return 0; -} - -static void perf_swevent_del(struct perf_event *event, int flags) -{ - hlist_del_rcu(&event->hlist_entry); -} - -static void perf_swevent_start(struct perf_event *event, int flags) -{ - event->hw.state = 0; -} - -static void perf_swevent_stop(struct perf_event *event, int flags) -{ - event->hw.state = PERF_HES_STOPPED; -} - -/* Deref the hlist from the update side */ -static inline struct swevent_hlist * -swevent_hlist_deref(struct swevent_htable *swhash) -{ - return rcu_dereference_protected(swhash->swevent_hlist, - lockdep_is_held(&swhash->hlist_mutex)); -} - -static void swevent_hlist_release_rcu(struct rcu_head *rcu_head) -{ - struct swevent_hlist *hlist; - - hlist = container_of(rcu_head, struct swevent_hlist, rcu_head); - kfree(hlist); -} - -static void swevent_hlist_release(struct swevent_htable *swhash) -{ - struct swevent_hlist *hlist = swevent_hlist_deref(swhash); - - if (!hlist) - return; - - rcu_assign_pointer(swhash->swevent_hlist, NULL); - call_rcu(&hlist->rcu_head, swevent_hlist_release_rcu); -} - -static void swevent_hlist_put_cpu(struct perf_event *event, int cpu) -{ - struct swevent_htable *swhash = &per_cpu(swevent_htable, cpu); - - mutex_lock(&swhash->hlist_mutex); - - if (!--swhash->hlist_refcount) - swevent_hlist_release(swhash); - - mutex_unlock(&swhash->hlist_mutex); -} - -static void swevent_hlist_put(struct perf_event *event) -{ - int cpu; - - if (event->cpu != -1) { - swevent_hlist_put_cpu(event, event->cpu); - return; - } - - for_each_possible_cpu(cpu) - swevent_hlist_put_cpu(event, cpu); -} - -static int swevent_hlist_get_cpu(struct perf_event *event, int cpu) -{ - struct swevent_htable *swhash = &per_cpu(swevent_htable, cpu); - int err = 0; - - mutex_lock(&swhash->hlist_mutex); - - if (!swevent_hlist_deref(swhash) && cpu_online(cpu)) { - struct swevent_hlist *hlist; - - hlist = kzalloc(sizeof(*hlist), GFP_KERNEL); - if (!hlist) { - err = -ENOMEM; - goto exit; - } - rcu_assign_pointer(swhash->swevent_hlist, hlist); - } - swhash->hlist_refcount++; -exit: - mutex_unlock(&swhash->hlist_mutex); - - return err; -} - -static int swevent_hlist_get(struct perf_event *event) -{ - int err; - int cpu, failed_cpu; - - if (event->cpu != -1) - return swevent_hlist_get_cpu(event, event->cpu); - - get_online_cpus(); - for_each_possible_cpu(cpu) { - err = swevent_hlist_get_cpu(event, cpu); - if (err) { - failed_cpu = cpu; - goto fail; - } - } - put_online_cpus(); - - return 0; -fail: - for_each_possible_cpu(cpu) { - if (cpu == failed_cpu) - break; - swevent_hlist_put_cpu(event, cpu); - } - - put_online_cpus(); - return err; -} - -struct jump_label_key perf_swevent_enabled[PERF_COUNT_SW_MAX]; - -static void sw_perf_event_destroy(struct perf_event *event) -{ - u64 event_id = event->attr.config; - - WARN_ON(event->parent); - - jump_label_dec(&perf_swevent_enabled[event_id]); - swevent_hlist_put(event); -} - -static int perf_swevent_init(struct perf_event *event) -{ - int event_id = event->attr.config; - - if (event->attr.type != PERF_TYPE_SOFTWARE) - return -ENOENT; - - switch (event_id) { - case PERF_COUNT_SW_CPU_CLOCK: - case PERF_COUNT_SW_TASK_CLOCK: - return -ENOENT; - - default: - break; - } - - if (event_id >= PERF_COUNT_SW_MAX) - return -ENOENT; - - if (!event->parent) { - int err; - - err = swevent_hlist_get(event); - if (err) - return err; - - jump_label_inc(&perf_swevent_enabled[event_id]); - event->destroy = sw_perf_event_destroy; - } - - return 0; -} - -static struct pmu perf_swevent = { - .task_ctx_nr = perf_sw_context, - - .event_init = perf_swevent_init, - .add = perf_swevent_add, - .del = perf_swevent_del, - .start = perf_swevent_start, - .stop = perf_swevent_stop, - .read = perf_swevent_read, -}; - -#ifdef CONFIG_EVENT_TRACING - -static int perf_tp_filter_match(struct perf_event *event, - struct perf_sample_data *data) -{ - void *record = data->raw->data; - - if (likely(!event->filter) || filter_match_preds(event->filter, record)) - return 1; - return 0; -} - -static int perf_tp_event_match(struct perf_event *event, - struct perf_sample_data *data, - struct pt_regs *regs) -{ - if (event->hw.state & PERF_HES_STOPPED) - return 0; - /* - * All tracepoints are from kernel-space. - */ - if (event->attr.exclude_kernel) - return 0; - - if (!perf_tp_filter_match(event, data)) - return 0; - - return 1; -} - -void perf_tp_event(u64 addr, u64 count, void *record, int entry_size, - struct pt_regs *regs, struct hlist_head *head, int rctx) -{ - struct perf_sample_data data; - struct perf_event *event; - struct hlist_node *node; - - struct perf_raw_record raw = { - .size = entry_size, - .data = record, - }; - - perf_sample_data_init(&data, addr); - data.raw = &raw; - - hlist_for_each_entry_rcu(event, node, head, hlist_entry) { - if (perf_tp_event_match(event, &data, regs)) - perf_swevent_event(event, count, 1, &data, regs); - } - - perf_swevent_put_recursion_context(rctx); -} -EXPORT_SYMBOL_GPL(perf_tp_event); - -static void tp_perf_event_destroy(struct perf_event *event) -{ - perf_trace_destroy(event); -} - -static int perf_tp_event_init(struct perf_event *event) -{ - int err; - - if (event->attr.type != PERF_TYPE_TRACEPOINT) - return -ENOENT; - - err = perf_trace_init(event); - if (err) - return err; - - event->destroy = tp_perf_event_destroy; - - return 0; -} - -static struct pmu perf_tracepoint = { - .task_ctx_nr = perf_sw_context, - - .event_init = perf_tp_event_init, - .add = perf_trace_add, - .del = perf_trace_del, - .start = perf_swevent_start, - .stop = perf_swevent_stop, - .read = perf_swevent_read, -}; - -static inline void perf_tp_register(void) -{ - perf_pmu_register(&perf_tracepoint, "tracepoint", PERF_TYPE_TRACEPOINT); -} - -static int perf_event_set_filter(struct perf_event *event, void __user *arg) -{ - char *filter_str; - int ret; - - if (event->attr.type != PERF_TYPE_TRACEPOINT) - return -EINVAL; - - filter_str = strndup_user(arg, PAGE_SIZE); - if (IS_ERR(filter_str)) - return PTR_ERR(filter_str); - - ret = ftrace_profile_set_filter(event, event->attr.config, filter_str); - - kfree(filter_str); - return ret; -} - -static void perf_event_free_filter(struct perf_event *event) -{ - ftrace_profile_free_filter(event); -} - -#else - -static inline void perf_tp_register(void) -{ -} - -static int perf_event_set_filter(struct perf_event *event, void __user *arg) -{ - return -ENOENT; -} - -static void perf_event_free_filter(struct perf_event *event) -{ -} - -#endif /* CONFIG_EVENT_TRACING */ - -#ifdef CONFIG_HAVE_HW_BREAKPOINT -void perf_bp_event(struct perf_event *bp, void *data) -{ - struct perf_sample_data sample; - struct pt_regs *regs = data; - - perf_sample_data_init(&sample, bp->attr.bp_addr); - - if (!bp->hw.state && !perf_exclude_event(bp, regs)) - perf_swevent_event(bp, 1, 1, &sample, regs); -} -#endif - -/* - * hrtimer based swevent callback - */ - -static enum hrtimer_restart perf_swevent_hrtimer(struct hrtimer *hrtimer) -{ - enum hrtimer_restart ret = HRTIMER_RESTART; - struct perf_sample_data data; - struct pt_regs *regs; - struct perf_event *event; - u64 period; - - event = container_of(hrtimer, struct perf_event, hw.hrtimer); - - if (event->state != PERF_EVENT_STATE_ACTIVE) - return HRTIMER_NORESTART; - - event->pmu->read(event); - - perf_sample_data_init(&data, 0); - data.period = event->hw.last_period; - regs = get_irq_regs(); - - if (regs && !perf_exclude_event(event, regs)) { - if (!(event->attr.exclude_idle && current->pid == 0)) - if (perf_event_overflow(event, 0, &data, regs)) - ret = HRTIMER_NORESTART; - } - - period = max_t(u64, 10000, event->hw.sample_period); - hrtimer_forward_now(hrtimer, ns_to_ktime(period)); - - return ret; -} - -static void perf_swevent_start_hrtimer(struct perf_event *event) -{ - struct hw_perf_event *hwc = &event->hw; - s64 period; - - if (!is_sampling_event(event)) - return; - - period = local64_read(&hwc->period_left); - if (period) { - if (period < 0) - period = 10000; - - local64_set(&hwc->period_left, 0); - } else { - period = max_t(u64, 10000, hwc->sample_period); - } - __hrtimer_start_range_ns(&hwc->hrtimer, - ns_to_ktime(period), 0, - HRTIMER_MODE_REL_PINNED, 0); -} - -static void perf_swevent_cancel_hrtimer(struct perf_event *event) -{ - struct hw_perf_event *hwc = &event->hw; - - if (is_sampling_event(event)) { - ktime_t remaining = hrtimer_get_remaining(&hwc->hrtimer); - local64_set(&hwc->period_left, ktime_to_ns(remaining)); - - hrtimer_cancel(&hwc->hrtimer); - } -} - -static void perf_swevent_init_hrtimer(struct perf_event *event) -{ - struct hw_perf_event *hwc = &event->hw; - - if (!is_sampling_event(event)) - return; - - hrtimer_init(&hwc->hrtimer, CLOCK_MONOTONIC, HRTIMER_MODE_REL); - hwc->hrtimer.function = perf_swevent_hrtimer; - - /* - * Since hrtimers have a fixed rate, we can do a static freq->period - * mapping and avoid the whole period adjust feedback stuff. - */ - if (event->attr.freq) { - long freq = event->attr.sample_freq; - - event->attr.sample_period = NSEC_PER_SEC / freq; - hwc->sample_period = event->attr.sample_period; - local64_set(&hwc->period_left, hwc->sample_period); - event->attr.freq = 0; - } -} - -/* - * Software event: cpu wall time clock - */ - -static void cpu_clock_event_update(struct perf_event *event) -{ - s64 prev; - u64 now; - - now = local_clock(); - prev = local64_xchg(&event->hw.prev_count, now); - local64_add(now - prev, &event->count); -} - -static void cpu_clock_event_start(struct perf_event *event, int flags) -{ - local64_set(&event->hw.prev_count, local_clock()); - perf_swevent_start_hrtimer(event); -} - -static void cpu_clock_event_stop(struct perf_event *event, int flags) -{ - perf_swevent_cancel_hrtimer(event); - cpu_clock_event_update(event); -} - -static int cpu_clock_event_add(struct perf_event *event, int flags) -{ - if (flags & PERF_EF_START) - cpu_clock_event_start(event, flags); - - return 0; -} - -static void cpu_clock_event_del(struct perf_event *event, int flags) -{ - cpu_clock_event_stop(event, flags); -} - -static void cpu_clock_event_read(struct perf_event *event) -{ - cpu_clock_event_update(event); -} - -static int cpu_clock_event_init(struct perf_event *event) -{ - if (event->attr.type != PERF_TYPE_SOFTWARE) - return -ENOENT; - - if (event->attr.config != PERF_COUNT_SW_CPU_CLOCK) - return -ENOENT; - - perf_swevent_init_hrtimer(event); - - return 0; -} - -static struct pmu perf_cpu_clock = { - .task_ctx_nr = perf_sw_context, - - .event_init = cpu_clock_event_init, - .add = cpu_clock_event_add, - .del = cpu_clock_event_del, - .start = cpu_clock_event_start, - .stop = cpu_clock_event_stop, - .read = cpu_clock_event_read, -}; - -/* - * Software event: task time clock - */ - -static void task_clock_event_update(struct perf_event *event, u64 now) -{ - u64 prev; - s64 delta; - - prev = local64_xchg(&event->hw.prev_count, now); - delta = now - prev; - local64_add(delta, &event->count); -} - -static void task_clock_event_start(struct perf_event *event, int flags) -{ - local64_set(&event->hw.prev_count, event->ctx->time); - perf_swevent_start_hrtimer(event); -} - -static void task_clock_event_stop(struct perf_event *event, int flags) -{ - perf_swevent_cancel_hrtimer(event); - task_clock_event_update(event, event->ctx->time); -} - -static int task_clock_event_add(struct perf_event *event, int flags) -{ - if (flags & PERF_EF_START) - task_clock_event_start(event, flags); - - return 0; -} - -static void task_clock_event_del(struct perf_event *event, int flags) -{ - task_clock_event_stop(event, PERF_EF_UPDATE); -} - -static void task_clock_event_read(struct perf_event *event) -{ - u64 now = perf_clock(); - u64 delta = now - event->ctx->timestamp; - u64 time = event->ctx->time + delta; - - task_clock_event_update(event, time); -} - -static int task_clock_event_init(struct perf_event *event) -{ - if (event->attr.type != PERF_TYPE_SOFTWARE) - return -ENOENT; - - if (event->attr.config != PERF_COUNT_SW_TASK_CLOCK) - return -ENOENT; - - perf_swevent_init_hrtimer(event); - - return 0; -} - -static struct pmu perf_task_clock = { - .task_ctx_nr = perf_sw_context, - - .event_init = task_clock_event_init, - .add = task_clock_event_add, - .del = task_clock_event_del, - .start = task_clock_event_start, - .stop = task_clock_event_stop, - .read = task_clock_event_read, -}; - -static void perf_pmu_nop_void(struct pmu *pmu) -{ -} - -static int perf_pmu_nop_int(struct pmu *pmu) -{ - return 0; -} - -static void perf_pmu_start_txn(struct pmu *pmu) -{ - perf_pmu_disable(pmu); -} - -static int perf_pmu_commit_txn(struct pmu *pmu) -{ - perf_pmu_enable(pmu); - return 0; -} - -static void perf_pmu_cancel_txn(struct pmu *pmu) -{ - perf_pmu_enable(pmu); -} - -/* - * Ensures all contexts with the same task_ctx_nr have the same - * pmu_cpu_context too. - */ -static void *find_pmu_context(int ctxn) -{ - struct pmu *pmu; - - if (ctxn < 0) - return NULL; - - list_for_each_entry(pmu, &pmus, entry) { - if (pmu->task_ctx_nr == ctxn) - return pmu->pmu_cpu_context; - } - - return NULL; -} - -static void update_pmu_context(struct pmu *pmu, struct pmu *old_pmu) -{ - int cpu; - - for_each_possible_cpu(cpu) { - struct perf_cpu_context *cpuctx; - - cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu); - - if (cpuctx->active_pmu == old_pmu) - cpuctx->active_pmu = pmu; - } -} - -static void free_pmu_context(struct pmu *pmu) -{ - struct pmu *i; - - mutex_lock(&pmus_lock); - /* - * Like a real lame refcount. - */ - list_for_each_entry(i, &pmus, entry) { - if (i->pmu_cpu_context == pmu->pmu_cpu_context) { - update_pmu_context(i, pmu); - goto out; - } - } - - free_percpu(pmu->pmu_cpu_context); -out: - mutex_unlock(&pmus_lock); -} -static struct idr pmu_idr; - -static ssize_t -type_show(struct device *dev, struct device_attribute *attr, char *page) -{ - struct pmu *pmu = dev_get_drvdata(dev); - - return snprintf(page, PAGE_SIZE-1, "%d\n", pmu->type); -} - -static struct device_attribute pmu_dev_attrs[] = { - __ATTR_RO(type), - __ATTR_NULL, -}; - -static int pmu_bus_running; -static struct bus_type pmu_bus = { - .name = "event_source", - .dev_attrs = pmu_dev_attrs, -}; - -static void pmu_dev_release(struct device *dev) -{ - kfree(dev); -} - -static int pmu_dev_alloc(struct pmu *pmu) -{ - int ret = -ENOMEM; - - pmu->dev = kzalloc(sizeof(struct device), GFP_KERNEL); - if (!pmu->dev) - goto out; - - device_initialize(pmu->dev); - ret = dev_set_name(pmu->dev, "%s", pmu->name); - if (ret) - goto free_dev; - - dev_set_drvdata(pmu->dev, pmu); - pmu->dev->bus = &pmu_bus; - pmu->dev->release = pmu_dev_release; - ret = device_add(pmu->dev); - if (ret) - goto free_dev; - -out: - return ret; - -free_dev: - put_device(pmu->dev); - goto out; -} - -static struct lock_class_key cpuctx_mutex; - -int perf_pmu_register(struct pmu *pmu, char *name, int type) -{ - int cpu, ret; - - mutex_lock(&pmus_lock); - ret = -ENOMEM; - pmu->pmu_disable_count = alloc_percpu(int); - if (!pmu->pmu_disable_count) - goto unlock; - - pmu->type = -1; - if (!name) - goto skip_type; - pmu->name = name; - - if (type < 0) { - int err = idr_pre_get(&pmu_idr, GFP_KERNEL); - if (!err) - goto free_pdc; - - err = idr_get_new_above(&pmu_idr, pmu, PERF_TYPE_MAX, &type); - if (err) { - ret = err; - goto free_pdc; - } - } - pmu->type = type; - - if (pmu_bus_running) { - ret = pmu_dev_alloc(pmu); - if (ret) - goto free_idr; - } - -skip_type: - pmu->pmu_cpu_context = find_pmu_context(pmu->task_ctx_nr); - if (pmu->pmu_cpu_context) - goto got_cpu_context; - - pmu->pmu_cpu_context = alloc_percpu(struct perf_cpu_context); - if (!pmu->pmu_cpu_context) - goto free_dev; - - for_each_possible_cpu(cpu) { - struct perf_cpu_context *cpuctx; - - cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu); - __perf_event_init_context(&cpuctx->ctx); - lockdep_set_class(&cpuctx->ctx.mutex, &cpuctx_mutex); - cpuctx->ctx.type = cpu_context; - cpuctx->ctx.pmu = pmu; - cpuctx->jiffies_interval = 1; - INIT_LIST_HEAD(&cpuctx->rotation_list); - cpuctx->active_pmu = pmu; - } - -got_cpu_context: - if (!pmu->start_txn) { - if (pmu->pmu_enable) { - /* - * If we have pmu_enable/pmu_disable calls, install - * transaction stubs that use that to try and batch - * hardware accesses. - */ - pmu->start_txn = perf_pmu_start_txn; - pmu->commit_txn = perf_pmu_commit_txn; - pmu->cancel_txn = perf_pmu_cancel_txn; - } else { - pmu->start_txn = perf_pmu_nop_void; - pmu->commit_txn = perf_pmu_nop_int; - pmu->cancel_txn = perf_pmu_nop_void; - } - } - - if (!pmu->pmu_enable) { - pmu->pmu_enable = perf_pmu_nop_void; - pmu->pmu_disable = perf_pmu_nop_void; - } - - list_add_rcu(&pmu->entry, &pmus); - ret = 0; -unlock: - mutex_unlock(&pmus_lock); - - return ret; - -free_dev: - device_del(pmu->dev); - put_device(pmu->dev); - -free_idr: - if (pmu->type >= PERF_TYPE_MAX) - idr_remove(&pmu_idr, pmu->type); - -free_pdc: - free_percpu(pmu->pmu_disable_count); - goto unlock; -} - -void perf_pmu_unregister(struct pmu *pmu) -{ - mutex_lock(&pmus_lock); - list_del_rcu(&pmu->entry); - mutex_unlock(&pmus_lock); - - /* - * We dereference the pmu list under both SRCU and regular RCU, so - * synchronize against both of those. - */ - synchronize_srcu(&pmus_srcu); - synchronize_rcu(); - - free_percpu(pmu->pmu_disable_count); - if (pmu->type >= PERF_TYPE_MAX) - idr_remove(&pmu_idr, pmu->type); - device_del(pmu->dev); - put_device(pmu->dev); - free_pmu_context(pmu); -} - -struct pmu *perf_init_event(struct perf_event *event) -{ - struct pmu *pmu = NULL; - int idx; - int ret; - - idx = srcu_read_lock(&pmus_srcu); - - rcu_read_lock(); - pmu = idr_find(&pmu_idr, event->attr.type); - rcu_read_unlock(); - if (pmu) { - ret = pmu->event_init(event); - if (ret) - pmu = ERR_PTR(ret); - goto unlock; - } - - list_for_each_entry_rcu(pmu, &pmus, entry) { - ret = pmu->event_init(event); - if (!ret) - goto unlock; - - if (ret != -ENOENT) { - pmu = ERR_PTR(ret); - goto unlock; - } - } - pmu = ERR_PTR(-ENOENT); -unlock: - srcu_read_unlock(&pmus_srcu, idx); - - return pmu; -} - -/* - * Allocate and initialize a event structure - */ -static struct perf_event * -perf_event_alloc(struct perf_event_attr *attr, int cpu, - struct task_struct *task, - struct perf_event *group_leader, - struct perf_event *parent_event, - perf_overflow_handler_t overflow_handler) -{ - struct pmu *pmu; - struct perf_event *event; - struct hw_perf_event *hwc; - long err; - - if ((unsigned)cpu >= nr_cpu_ids) { - if (!task || cpu != -1) - return ERR_PTR(-EINVAL); - } - - event = kzalloc(sizeof(*event), GFP_KERNEL); - if (!event) - return ERR_PTR(-ENOMEM); - - /* - * Single events are their own group leaders, with an - * empty sibling list: - */ - if (!group_leader) - group_leader = event; - - mutex_init(&event->child_mutex); - INIT_LIST_HEAD(&event->child_list); - - INIT_LIST_HEAD(&event->group_entry); - INIT_LIST_HEAD(&event->event_entry); - INIT_LIST_HEAD(&event->sibling_list); - init_waitqueue_head(&event->waitq); - init_irq_work(&event->pending, perf_pending_event); - - mutex_init(&event->mmap_mutex); - - event->cpu = cpu; - event->attr = *attr; - event->group_leader = group_leader; - event->pmu = NULL; - event->oncpu = -1; - - event->parent = parent_event; - - event->ns = get_pid_ns(current->nsproxy->pid_ns); - event->id = atomic64_inc_return(&perf_event_id); - - event->state = PERF_EVENT_STATE_INACTIVE; - - if (task) { - event->attach_state = PERF_ATTACH_TASK; -#ifdef CONFIG_HAVE_HW_BREAKPOINT - /* - * hw_breakpoint is a bit difficult here.. - */ - if (attr->type == PERF_TYPE_BREAKPOINT) - event->hw.bp_target = task; -#endif - } - - if (!overflow_handler && parent_event) - overflow_handler = parent_event->overflow_handler; - - event->overflow_handler = overflow_handler; - - if (attr->disabled) - event->state = PERF_EVENT_STATE_OFF; - - pmu = NULL; - - hwc = &event->hw; - hwc->sample_period = attr->sample_period; - if (attr->freq && attr->sample_freq) - hwc->sample_period = 1; - hwc->last_period = hwc->sample_period; - - local64_set(&hwc->period_left, hwc->sample_period); - - /* - * we currently do not support PERF_FORMAT_GROUP on inherited events - */ - if (attr->inherit && (attr->read_format & PERF_FORMAT_GROUP)) - goto done; - - pmu = perf_init_event(event); - -done: - err = 0; - if (!pmu) - err = -EINVAL; - else if (IS_ERR(pmu)) - err = PTR_ERR(pmu); - - if (err) { - if (event->ns) - put_pid_ns(event->ns); - kfree(event); - return ERR_PTR(err); - } - - event->pmu = pmu; - - if (!event->parent) { - if (event->attach_state & PERF_ATTACH_TASK) - jump_label_inc(&perf_sched_events); - if (event->attr.mmap || event->attr.mmap_data) - atomic_inc(&nr_mmap_events); - if (event->attr.comm) - atomic_inc(&nr_comm_events); - if (event->attr.task) - atomic_inc(&nr_task_events); - if (event->attr.sample_type & PERF_SAMPLE_CALLCHAIN) { - err = get_callchain_buffers(); - if (err) { - free_event(event); - return ERR_PTR(err); - } - } - } - - return event; -} - -static int perf_copy_attr(struct perf_event_attr __user *uattr, - struct perf_event_attr *attr) -{ - u32 size; - int ret; - - if (!access_ok(VERIFY_WRITE, uattr, PERF_ATTR_SIZE_VER0)) - return -EFAULT; - - /* - * zero the full structure, so that a short copy will be nice. - */ - memset(attr, 0, sizeof(*attr)); - - ret = get_user(size, &uattr->size); - if (ret) - return ret; - - if (size > PAGE_SIZE) /* silly large */ - goto err_size; - - if (!size) /* abi compat */ - size = PERF_ATTR_SIZE_VER0; - - if (size < PERF_ATTR_SIZE_VER0) - goto err_size; - - /* - * If we're handed a bigger struct than we know of, - * ensure all the unknown bits are 0 - i.e. new - * user-space does not rely on any kernel feature - * extensions we dont know about yet. - */ - if (size > sizeof(*attr)) { - unsigned char __user *addr; - unsigned char __user *end; - unsigned char val; - - addr = (void __user *)uattr + sizeof(*attr); - end = (void __user *)uattr + size; - - for (; addr < end; addr++) { - ret = get_user(val, addr); - if (ret) - return ret; - if (val) - goto err_size; - } - size = sizeof(*attr); - } - - ret = copy_from_user(attr, uattr, size); - if (ret) - return -EFAULT; - - /* - * If the type exists, the corresponding creation will verify - * the attr->config. - */ - if (attr->type >= PERF_TYPE_MAX) - return -EINVAL; - - if (attr->__reserved_1) - return -EINVAL; - - if (attr->sample_type & ~(PERF_SAMPLE_MAX-1)) - return -EINVAL; - - if (attr->read_format & ~(PERF_FORMAT_MAX-1)) - return -EINVAL; - -out: - return ret; - -err_size: - put_user(sizeof(*attr), &uattr->size); - ret = -E2BIG; - goto out; -} - -static int -perf_event_set_output(struct perf_event *event, struct perf_event *output_event) -{ - struct perf_buffer *buffer = NULL, *old_buffer = NULL; - int ret = -EINVAL; - - if (!output_event) - goto set; - - /* don't allow circular references */ - if (event == output_event) - goto out; - - /* - * Don't allow cross-cpu buffers - */ - if (output_event->cpu != event->cpu) - goto out; - - /* - * If its not a per-cpu buffer, it must be the same task. - */ - if (output_event->cpu == -1 && output_event->ctx != event->ctx) - goto out; - -set: - mutex_lock(&event->mmap_mutex); - /* Can't redirect output if we've got an active mmap() */ - if (atomic_read(&event->mmap_count)) - goto unlock; - - if (output_event) { - /* get the buffer we want to redirect to */ - buffer = perf_buffer_get(output_event); - if (!buffer) - goto unlock; - } - - old_buffer = event->buffer; - rcu_assign_pointer(event->buffer, buffer); - ret = 0; -unlock: - mutex_unlock(&event->mmap_mutex); - - if (old_buffer) - perf_buffer_put(old_buffer); -out: - return ret; -} - -/** - * sys_perf_event_open - open a performance event, associate it to a task/cpu - * - * @attr_uptr: event_id type attributes for monitoring/sampling - * @pid: target pid - * @cpu: target cpu - * @group_fd: group leader event fd - */ -SYSCALL_DEFINE5(perf_event_open, - struct perf_event_attr __user *, attr_uptr, - pid_t, pid, int, cpu, int, group_fd, unsigned long, flags) -{ - struct perf_event *group_leader = NULL, *output_event = NULL; - struct perf_event *event, *sibling; - struct perf_event_attr attr; - struct perf_event_context *ctx; - struct file *event_file = NULL; - struct file *group_file = NULL; - struct task_struct *task = NULL; - struct pmu *pmu; - int event_fd; - int move_group = 0; - int fput_needed = 0; - int err; - - /* for future expandability... */ - if (flags & ~PERF_FLAG_ALL) - return -EINVAL; - - err = perf_copy_attr(attr_uptr, &attr); - if (err) - return err; - - if (!attr.exclude_kernel) { - if (perf_paranoid_kernel() && !capable(CAP_SYS_ADMIN)) - return -EACCES; - } - - if (attr.freq) { - if (attr.sample_freq > sysctl_perf_event_sample_rate) - return -EINVAL; - } - - /* - * In cgroup mode, the pid argument is used to pass the fd - * opened to the cgroup directory in cgroupfs. The cpu argument - * designates the cpu on which to monitor threads from that - * cgroup. - */ - if ((flags & PERF_FLAG_PID_CGROUP) && (pid == -1 || cpu == -1)) - return -EINVAL; - - event_fd = get_unused_fd_flags(O_RDWR); - if (event_fd < 0) - return event_fd; - - if (group_fd != -1) { - group_leader = perf_fget_light(group_fd, &fput_needed); - if (IS_ERR(group_leader)) { - err = PTR_ERR(group_leader); - goto err_fd; - } - group_file = group_leader->filp; - if (flags & PERF_FLAG_FD_OUTPUT) - output_event = group_leader; - if (flags & PERF_FLAG_FD_NO_GROUP) - group_leader = NULL; - } - - if (pid != -1 && !(flags & PERF_FLAG_PID_CGROUP)) { - task = find_lively_task_by_vpid(pid); - if (IS_ERR(task)) { - err = PTR_ERR(task); - goto err_group_fd; - } - } - - event = perf_event_alloc(&attr, cpu, task, group_leader, NULL, NULL); - if (IS_ERR(event)) { - err = PTR_ERR(event); - goto err_task; - } - - if (flags & PERF_FLAG_PID_CGROUP) { - err = perf_cgroup_connect(pid, event, &attr, group_leader); - if (err) - goto err_alloc; - /* - * one more event: - * - that has cgroup constraint on event->cpu - * - that may need work on context switch - */ - atomic_inc(&per_cpu(perf_cgroup_events, event->cpu)); - jump_label_inc(&perf_sched_events); - } - - /* - * Special case software events and allow them to be part of - * any hardware group. - */ - pmu = event->pmu; - - if (group_leader && - (is_software_event(event) != is_software_event(group_leader))) { - if (is_software_event(event)) { - /* - * If event and group_leader are not both a software - * event, and event is, then group leader is not. - * - * Allow the addition of software events to !software - * groups, this is safe because software events never - * fail to schedule. - */ - pmu = group_leader->pmu; - } else if (is_software_event(group_leader) && - (group_leader->group_flags & PERF_GROUP_SOFTWARE)) { - /* - * In case the group is a pure software group, and we - * try to add a hardware event, move the whole group to - * the hardware context. - */ - move_group = 1; - } - } - - /* - * Get the target context (task or percpu): - */ - ctx = find_get_context(pmu, task, cpu); - if (IS_ERR(ctx)) { - err = PTR_ERR(ctx); - goto err_alloc; - } - - if (task) { - put_task_struct(task); - task = NULL; - } - - /* - * Look up the group leader (we will attach this event to it): - */ - if (group_leader) { - err = -EINVAL; - - /* - * Do not allow a recursive hierarchy (this new sibling - * becoming part of another group-sibling): - */ - if (group_leader->group_leader != group_leader) - goto err_context; - /* - * Do not allow to attach to a group in a different - * task or CPU context: - */ - if (move_group) { - if (group_leader->ctx->type != ctx->type) - goto err_context; - } else { - if (group_leader->ctx != ctx) - goto err_context; - } - - /* - * Only a group leader can be exclusive or pinned - */ - if (attr.exclusive || attr.pinned) - goto err_context; - } - - if (output_event) { - err = perf_event_set_output(event, output_event); - if (err) - goto err_context; - } - - event_file = anon_inode_getfile("[perf_event]", &perf_fops, event, O_RDWR); - if (IS_ERR(event_file)) { - err = PTR_ERR(event_file); - goto err_context; - } - - if (move_group) { - struct perf_event_context *gctx = group_leader->ctx; - - mutex_lock(&gctx->mutex); - perf_remove_from_context(group_leader); - list_for_each_entry(sibling, &group_leader->sibling_list, - group_entry) { - perf_remove_from_context(sibling); - put_ctx(gctx); - } - mutex_unlock(&gctx->mutex); - put_ctx(gctx); - } - - event->filp = event_file; - WARN_ON_ONCE(ctx->parent_ctx); - mutex_lock(&ctx->mutex); - - if (move_group) { - perf_install_in_context(ctx, group_leader, cpu); - get_ctx(ctx); - list_for_each_entry(sibling, &group_leader->sibling_list, - group_entry) { - perf_install_in_context(ctx, sibling, cpu); - get_ctx(ctx); - } - } - - perf_install_in_context(ctx, event, cpu); - ++ctx->generation; - perf_unpin_context(ctx); - mutex_unlock(&ctx->mutex); - - event->owner = current; - - mutex_lock(¤t->perf_event_mutex); - list_add_tail(&event->owner_entry, ¤t->perf_event_list); - mutex_unlock(¤t->perf_event_mutex); - - /* - * Precalculate sample_data sizes - */ - perf_event__header_size(event); - perf_event__id_header_size(event); - - /* - * Drop the reference on the group_event after placing the - * new event on the sibling_list. This ensures destruction - * of the group leader will find the pointer to itself in - * perf_group_detach(). - */ - fput_light(group_file, fput_needed); - fd_install(event_fd, event_file); - return event_fd; - -err_context: - perf_unpin_context(ctx); - put_ctx(ctx); -err_alloc: - free_event(event); -err_task: - if (task) - put_task_struct(task); -err_group_fd: - fput_light(group_file, fput_needed); -err_fd: - put_unused_fd(event_fd); - return err; -} - -/** - * perf_event_create_kernel_counter - * - * @attr: attributes of the counter to create - * @cpu: cpu in which the counter is bound - * @task: task to profile (NULL for percpu) - */ -struct perf_event * -perf_event_create_kernel_counter(struct perf_event_attr *attr, int cpu, - struct task_struct *task, - perf_overflow_handler_t overflow_handler) -{ - struct perf_event_context *ctx; - struct perf_event *event; - int err; - - /* - * Get the target context (task or percpu): - */ - - event = perf_event_alloc(attr, cpu, task, NULL, NULL, overflow_handler); - if (IS_ERR(event)) { - err = PTR_ERR(event); - goto err; - } - - ctx = find_get_context(event->pmu, task, cpu); - if (IS_ERR(ctx)) { - err = PTR_ERR(ctx); - goto err_free; - } - - event->filp = NULL; - WARN_ON_ONCE(ctx->parent_ctx); - mutex_lock(&ctx->mutex); - perf_install_in_context(ctx, event, cpu); - ++ctx->generation; - perf_unpin_context(ctx); - mutex_unlock(&ctx->mutex); - - return event; - -err_free: - free_event(event); -err: - return ERR_PTR(err); -} -EXPORT_SYMBOL_GPL(perf_event_create_kernel_counter); - -static void sync_child_event(struct perf_event *child_event, - struct task_struct *child) -{ - struct perf_event *parent_event = child_event->parent; - u64 child_val; - - if (child_event->attr.inherit_stat) - perf_event_read_event(child_event, child); - - child_val = perf_event_count(child_event); - - /* - * Add back the child's count to the parent's count: - */ - atomic64_add(child_val, &parent_event->child_count); - atomic64_add(child_event->total_time_enabled, - &parent_event->child_total_time_enabled); - atomic64_add(child_event->total_time_running, - &parent_event->child_total_time_running); - - /* - * Remove this event from the parent's list - */ - WARN_ON_ONCE(parent_event->ctx->parent_ctx); - mutex_lock(&parent_event->child_mutex); - list_del_init(&child_event->child_list); - mutex_unlock(&parent_event->child_mutex); - - /* - * Release the parent event, if this was the last - * reference to it. - */ - fput(parent_event->filp); -} - -static void -__perf_event_exit_task(struct perf_event *child_event, - struct perf_event_context *child_ctx, - struct task_struct *child) -{ - if (child_event->parent) { - raw_spin_lock_irq(&child_ctx->lock); - perf_group_detach(child_event); - raw_spin_unlock_irq(&child_ctx->lock); - } - - perf_remove_from_context(child_event); - - /* - * It can happen that the parent exits first, and has events - * that are still around due to the child reference. These - * events need to be zapped. - */ - if (child_event->parent) { - sync_child_event(child_event, child); - free_event(child_event); - } -} - -static void perf_event_exit_task_context(struct task_struct *child, int ctxn) -{ - struct perf_event *child_event, *tmp; - struct perf_event_context *child_ctx; - unsigned long flags; - - if (likely(!child->perf_event_ctxp[ctxn])) { - perf_event_task(child, NULL, 0); - return; - } - - local_irq_save(flags); - /* - * We can't reschedule here because interrupts are disabled, - * and either child is current or it is a task that can't be - * scheduled, so we are now safe from rescheduling changing - * our context. - */ - child_ctx = rcu_dereference_raw(child->perf_event_ctxp[ctxn]); - task_ctx_sched_out(child_ctx, EVENT_ALL); - - /* - * Take the context lock here so that if find_get_context is - * reading child->perf_event_ctxp, we wait until it has - * incremented the context's refcount before we do put_ctx below. - */ - raw_spin_lock(&child_ctx->lock); - child->perf_event_ctxp[ctxn] = NULL; - /* - * If this context is a clone; unclone it so it can't get - * swapped to another process while we're removing all - * the events from it. - */ - unclone_ctx(child_ctx); - update_context_time(child_ctx); - raw_spin_unlock_irqrestore(&child_ctx->lock, flags); - - /* - * Report the task dead after unscheduling the events so that we - * won't get any samples after PERF_RECORD_EXIT. We can however still - * get a few PERF_RECORD_READ events. - */ - perf_event_task(child, child_ctx, 0); - - /* - * We can recurse on the same lock type through: - * - * __perf_event_exit_task() - * sync_child_event() - * fput(parent_event->filp) - * perf_release() - * mutex_lock(&ctx->mutex) - * - * But since its the parent context it won't be the same instance. - */ - mutex_lock(&child_ctx->mutex); - -again: - list_for_each_entry_safe(child_event, tmp, &child_ctx->pinned_groups, - group_entry) - __perf_event_exit_task(child_event, child_ctx, child); - - list_for_each_entry_safe(child_event, tmp, &child_ctx->flexible_groups, - group_entry) - __perf_event_exit_task(child_event, child_ctx, child); - - /* - * If the last event was a group event, it will have appended all - * its siblings to the list, but we obtained 'tmp' before that which - * will still point to the list head terminating the iteration. - */ - if (!list_empty(&child_ctx->pinned_groups) || - !list_empty(&child_ctx->flexible_groups)) - goto again; - - mutex_unlock(&child_ctx->mutex); - - put_ctx(child_ctx); -} - -/* - * When a child task exits, feed back event values to parent events. - */ -void perf_event_exit_task(struct task_struct *child) -{ - struct perf_event *event, *tmp; - int ctxn; - - mutex_lock(&child->perf_event_mutex); - list_for_each_entry_safe(event, tmp, &child->perf_event_list, - owner_entry) { - list_del_init(&event->owner_entry); - - /* - * Ensure the list deletion is visible before we clear - * the owner, closes a race against perf_release() where - * we need to serialize on the owner->perf_event_mutex. - */ - smp_wmb(); - event->owner = NULL; - } - mutex_unlock(&child->perf_event_mutex); - - for_each_task_context_nr(ctxn) - perf_event_exit_task_context(child, ctxn); -} - -static void perf_free_event(struct perf_event *event, - struct perf_event_context *ctx) -{ - struct perf_event *parent = event->parent; - - if (WARN_ON_ONCE(!parent)) - return; - - mutex_lock(&parent->child_mutex); - list_del_init(&event->child_list); - mutex_unlock(&parent->child_mutex); - - fput(parent->filp); - - perf_group_detach(event); - list_del_event(event, ctx); - free_event(event); -} - -/* - * free an unexposed, unused context as created by inheritance by - * perf_event_init_task below, used by fork() in case of fail. - */ -void perf_event_free_task(struct task_struct *task) -{ - struct perf_event_context *ctx; - struct perf_event *event, *tmp; - int ctxn; - - for_each_task_context_nr(ctxn) { - ctx = task->perf_event_ctxp[ctxn]; - if (!ctx) - continue; - - mutex_lock(&ctx->mutex); -again: - list_for_each_entry_safe(event, tmp, &ctx->pinned_groups, - group_entry) - perf_free_event(event, ctx); - - list_for_each_entry_safe(event, tmp, &ctx->flexible_groups, - group_entry) - perf_free_event(event, ctx); - - if (!list_empty(&ctx->pinned_groups) || - !list_empty(&ctx->flexible_groups)) - goto again; - - mutex_unlock(&ctx->mutex); - - put_ctx(ctx); - } -} - -void perf_event_delayed_put(struct task_struct *task) -{ - int ctxn; - - for_each_task_context_nr(ctxn) - WARN_ON_ONCE(task->perf_event_ctxp[ctxn]); -} - -/* - * inherit a event from parent task to child task: - */ -static struct perf_event * -inherit_event(struct perf_event *parent_event, - struct task_struct *parent, - struct perf_event_context *parent_ctx, - struct task_struct *child, - struct perf_event *group_leader, - struct perf_event_context *child_ctx) -{ - struct perf_event *child_event; - unsigned long flags; - - /* - * Instead of creating recursive hierarchies of events, - * we link inherited events back to the original parent, - * which has a filp for sure, which we use as the reference - * count: - */ - if (parent_event->parent) - parent_event = parent_event->parent; - - child_event = perf_event_alloc(&parent_event->attr, - parent_event->cpu, - child, - group_leader, parent_event, - NULL); - if (IS_ERR(child_event)) - return child_event; - get_ctx(child_ctx); - - /* - * Make the child state follow the state of the parent event, - * not its attr.disabled bit. We hold the parent's mutex, - * so we won't race with perf_event_{en, dis}able_family. - */ - if (parent_event->state >= PERF_EVENT_STATE_INACTIVE) - child_event->state = PERF_EVENT_STATE_INACTIVE; - else - child_event->state = PERF_EVENT_STATE_OFF; - - if (parent_event->attr.freq) { - u64 sample_period = parent_event->hw.sample_period; - struct hw_perf_event *hwc = &child_event->hw; - - hwc->sample_period = sample_period; - hwc->last_period = sample_period; - - local64_set(&hwc->period_left, sample_period); - } - - child_event->ctx = child_ctx; - child_event->overflow_handler = parent_event->overflow_handler; - - /* - * Precalculate sample_data sizes - */ - perf_event__header_size(child_event); - perf_event__id_header_size(child_event); - - /* - * Link it up in the child's context: - */ - raw_spin_lock_irqsave(&child_ctx->lock, flags); - add_event_to_ctx(child_event, child_ctx); - raw_spin_unlock_irqrestore(&child_ctx->lock, flags); - - /* - * Get a reference to the parent filp - we will fput it - * when the child event exits. This is safe to do because - * we are in the parent and we know that the filp still - * exists and has a nonzero count: - */ - atomic_long_inc(&parent_event->filp->f_count); - - /* - * Link this into the parent event's child list - */ - WARN_ON_ONCE(parent_event->ctx->parent_ctx); - mutex_lock(&parent_event->child_mutex); - list_add_tail(&child_event->child_list, &parent_event->child_list); - mutex_unlock(&parent_event->child_mutex); - - return child_event; -} - -static int inherit_group(struct perf_event *parent_event, - struct task_struct *parent, - struct perf_event_context *parent_ctx, - struct task_struct *child, - struct perf_event_context *child_ctx) -{ - struct perf_event *leader; - struct perf_event *sub; - struct perf_event *child_ctr; - - leader = inherit_event(parent_event, parent, parent_ctx, - child, NULL, child_ctx); - if (IS_ERR(leader)) - return PTR_ERR(leader); - list_for_each_entry(sub, &parent_event->sibling_list, group_entry) { - child_ctr = inherit_event(sub, parent, parent_ctx, - child, leader, child_ctx); - if (IS_ERR(child_ctr)) - return PTR_ERR(child_ctr); - } - return 0; -} - -static int -inherit_task_group(struct perf_event *event, struct task_struct *parent, - struct perf_event_context *parent_ctx, - struct task_struct *child, int ctxn, - int *inherited_all) -{ - int ret; - struct perf_event_context *child_ctx; - - if (!event->attr.inherit) { - *inherited_all = 0; - return 0; - } - - child_ctx = child->perf_event_ctxp[ctxn]; - if (!child_ctx) { - /* - * This is executed from the parent task context, so - * inherit events that have been marked for cloning. - * First allocate and initialize a context for the - * child. - */ - - child_ctx = alloc_perf_context(event->pmu, child); - if (!child_ctx) - return -ENOMEM; - - child->perf_event_ctxp[ctxn] = child_ctx; - } - - ret = inherit_group(event, parent, parent_ctx, - child, child_ctx); - - if (ret) - *inherited_all = 0; - - return ret; -} - -/* - * Initialize the perf_event context in task_struct - */ -int perf_event_init_context(struct task_struct *child, int ctxn) -{ - struct perf_event_context *child_ctx, *parent_ctx; - struct perf_event_context *cloned_ctx; - struct perf_event *event; - struct task_struct *parent = current; - int inherited_all = 1; - unsigned long flags; - int ret = 0; - - if (likely(!parent->perf_event_ctxp[ctxn])) - return 0; - - /* - * If the parent's context is a clone, pin it so it won't get - * swapped under us. - */ - parent_ctx = perf_pin_task_context(parent, ctxn); - - /* - * No need to check if parent_ctx != NULL here; since we saw - * it non-NULL earlier, the only reason for it to become NULL - * is if we exit, and since we're currently in the middle of - * a fork we can't be exiting at the same time. - */ - - /* - * Lock the parent list. No need to lock the child - not PID - * hashed yet and not running, so nobody can access it. - */ - mutex_lock(&parent_ctx->mutex); - - /* - * We dont have to disable NMIs - we are only looking at - * the list, not manipulating it: - */ - list_for_each_entry(event, &parent_ctx->pinned_groups, group_entry) { - ret = inherit_task_group(event, parent, parent_ctx, - child, ctxn, &inherited_all); - if (ret) - break; - } - - /* - * We can't hold ctx->lock when iterating the ->flexible_group list due - * to allocations, but we need to prevent rotation because - * rotate_ctx() will change the list from interrupt context. - */ - raw_spin_lock_irqsave(&parent_ctx->lock, flags); - parent_ctx->rotate_disable = 1; - raw_spin_unlock_irqrestore(&parent_ctx->lock, flags); - - list_for_each_entry(event, &parent_ctx->flexible_groups, group_entry) { - ret = inherit_task_group(event, parent, parent_ctx, - child, ctxn, &inherited_all); - if (ret) - break; - } - - raw_spin_lock_irqsave(&parent_ctx->lock, flags); - parent_ctx->rotate_disable = 0; - - child_ctx = child->perf_event_ctxp[ctxn]; - - if (child_ctx && inherited_all) { - /* - * Mark the child context as a clone of the parent - * context, or of whatever the parent is a clone of. - * - * Note that if the parent is a clone, the holding of - * parent_ctx->lock avoids it from being uncloned. - */ - cloned_ctx = parent_ctx->parent_ctx; - if (cloned_ctx) { - child_ctx->parent_ctx = cloned_ctx; - child_ctx->parent_gen = parent_ctx->parent_gen; - } else { - child_ctx->parent_ctx = parent_ctx; - child_ctx->parent_gen = parent_ctx->generation; - } - get_ctx(child_ctx->parent_ctx); - } - - raw_spin_unlock_irqrestore(&parent_ctx->lock, flags); - mutex_unlock(&parent_ctx->mutex); - - perf_unpin_context(parent_ctx); - put_ctx(parent_ctx); - - return ret; -} - -/* - * Initialize the perf_event context in task_struct - */ -int perf_event_init_task(struct task_struct *child) -{ - int ctxn, ret; - - memset(child->perf_event_ctxp, 0, sizeof(child->perf_event_ctxp)); - mutex_init(&child->perf_event_mutex); - INIT_LIST_HEAD(&child->perf_event_list); - - for_each_task_context_nr(ctxn) { - ret = perf_event_init_context(child, ctxn); - if (ret) - return ret; - } - - return 0; -} - -static void __init perf_event_init_all_cpus(void) -{ - struct swevent_htable *swhash; - int cpu; - - for_each_possible_cpu(cpu) { - swhash = &per_cpu(swevent_htable, cpu); - mutex_init(&swhash->hlist_mutex); - INIT_LIST_HEAD(&per_cpu(rotation_list, cpu)); - } -} - -static void __cpuinit perf_event_init_cpu(int cpu) -{ - struct swevent_htable *swhash = &per_cpu(swevent_htable, cpu); - - mutex_lock(&swhash->hlist_mutex); - if (swhash->hlist_refcount > 0) { - struct swevent_hlist *hlist; - - hlist = kzalloc_node(sizeof(*hlist), GFP_KERNEL, cpu_to_node(cpu)); - WARN_ON(!hlist); - rcu_assign_pointer(swhash->swevent_hlist, hlist); - } - mutex_unlock(&swhash->hlist_mutex); -} - -#if defined CONFIG_HOTPLUG_CPU || defined CONFIG_KEXEC -static void perf_pmu_rotate_stop(struct pmu *pmu) -{ - struct perf_cpu_context *cpuctx = this_cpu_ptr(pmu->pmu_cpu_context); - - WARN_ON(!irqs_disabled()); - - list_del_init(&cpuctx->rotation_list); -} - -static void __perf_event_exit_context(void *__info) -{ - struct perf_event_context *ctx = __info; - struct perf_event *event, *tmp; - - perf_pmu_rotate_stop(ctx->pmu); - - list_for_each_entry_safe(event, tmp, &ctx->pinned_groups, group_entry) - __perf_remove_from_context(event); - list_for_each_entry_safe(event, tmp, &ctx->flexible_groups, group_entry) - __perf_remove_from_context(event); -} - -static void perf_event_exit_cpu_context(int cpu) -{ - struct perf_event_context *ctx; - struct pmu *pmu; - int idx; - - idx = srcu_read_lock(&pmus_srcu); - list_for_each_entry_rcu(pmu, &pmus, entry) { - ctx = &per_cpu_ptr(pmu->pmu_cpu_context, cpu)->ctx; - - mutex_lock(&ctx->mutex); - smp_call_function_single(cpu, __perf_event_exit_context, ctx, 1); - mutex_unlock(&ctx->mutex); - } - srcu_read_unlock(&pmus_srcu, idx); -} - -static void perf_event_exit_cpu(int cpu) -{ - struct swevent_htable *swhash = &per_cpu(swevent_htable, cpu); - - mutex_lock(&swhash->hlist_mutex); - swevent_hlist_release(swhash); - mutex_unlock(&swhash->hlist_mutex); - - perf_event_exit_cpu_context(cpu); -} -#else -static inline void perf_event_exit_cpu(int cpu) { } -#endif - -static int -perf_reboot(struct notifier_block *notifier, unsigned long val, void *v) -{ - int cpu; - - for_each_online_cpu(cpu) - perf_event_exit_cpu(cpu); - - return NOTIFY_OK; -} - -/* - * Run the perf reboot notifier at the very last possible moment so that - * the generic watchdog code runs as long as possible. - */ -static struct notifier_block perf_reboot_notifier = { - .notifier_call = perf_reboot, - .priority = INT_MIN, -}; - -static int __cpuinit -perf_cpu_notify(struct notifier_block *self, unsigned long action, void *hcpu) -{ - unsigned int cpu = (long)hcpu; - - switch (action & ~CPU_TASKS_FROZEN) { - - case CPU_UP_PREPARE: - case CPU_DOWN_FAILED: - perf_event_init_cpu(cpu); - break; - - case CPU_UP_CANCELED: - case CPU_DOWN_PREPARE: - perf_event_exit_cpu(cpu); - break; - - default: - break; - } - - return NOTIFY_OK; -} - -void __init perf_event_init(void) -{ - int ret; - - idr_init(&pmu_idr); - - perf_event_init_all_cpus(); - init_srcu_struct(&pmus_srcu); - perf_pmu_register(&perf_swevent, "software", PERF_TYPE_SOFTWARE); - perf_pmu_register(&perf_cpu_clock, NULL, -1); - perf_pmu_register(&perf_task_clock, NULL, -1); - perf_tp_register(); - perf_cpu_notifier(perf_cpu_notify); - register_reboot_notifier(&perf_reboot_notifier); - - ret = init_hw_breakpoint(); - WARN(ret, "hw_breakpoint initialization failed with: %d", ret); -} - -static int __init perf_event_sysfs_init(void) -{ - struct pmu *pmu; - int ret; - - mutex_lock(&pmus_lock); - - ret = bus_register(&pmu_bus); - if (ret) - goto unlock; - - list_for_each_entry(pmu, &pmus, entry) { - if (!pmu->name || pmu->type < 0) - continue; - - ret = pmu_dev_alloc(pmu); - WARN(ret, "Failed to register pmu: %s, reason %d\n", pmu->name, ret); - } - pmu_bus_running = 1; - ret = 0; - -unlock: - mutex_unlock(&pmus_lock); - - return ret; -} -device_initcall(perf_event_sysfs_init); - -#ifdef CONFIG_CGROUP_PERF -static struct cgroup_subsys_state *perf_cgroup_create( - struct cgroup_subsys *ss, struct cgroup *cont) -{ - struct perf_cgroup *jc; - - jc = kzalloc(sizeof(*jc), GFP_KERNEL); - if (!jc) - return ERR_PTR(-ENOMEM); - - jc->info = alloc_percpu(struct perf_cgroup_info); - if (!jc->info) { - kfree(jc); - return ERR_PTR(-ENOMEM); - } - - return &jc->css; -} - -static void perf_cgroup_destroy(struct cgroup_subsys *ss, - struct cgroup *cont) -{ - struct perf_cgroup *jc; - jc = container_of(cgroup_subsys_state(cont, perf_subsys_id), - struct perf_cgroup, css); - free_percpu(jc->info); - kfree(jc); -} - -static int __perf_cgroup_move(void *info) -{ - struct task_struct *task = info; - perf_cgroup_switch(task, PERF_CGROUP_SWOUT | PERF_CGROUP_SWIN); - return 0; -} - -static void perf_cgroup_move(struct task_struct *task) -{ - task_function_call(task, __perf_cgroup_move, task); -} - -static void perf_cgroup_attach(struct cgroup_subsys *ss, struct cgroup *cgrp, - struct cgroup *old_cgrp, struct task_struct *task, - bool threadgroup) -{ - perf_cgroup_move(task); - if (threadgroup) { - struct task_struct *c; - rcu_read_lock(); - list_for_each_entry_rcu(c, &task->thread_group, thread_group) { - perf_cgroup_move(c); - } - rcu_read_unlock(); - } -} - -static void perf_cgroup_exit(struct cgroup_subsys *ss, struct cgroup *cgrp, - struct cgroup *old_cgrp, struct task_struct *task) -{ - /* - * cgroup_exit() is called in the copy_process() failure path. - * Ignore this case since the task hasn't ran yet, this avoids - * trying to poke a half freed task state from generic code. - */ - if (!(task->flags & PF_EXITING)) - return; - - perf_cgroup_move(task); -} - -struct cgroup_subsys perf_subsys = { - .name = "perf_event", - .subsys_id = perf_subsys_id, - .create = perf_cgroup_create, - .destroy = perf_cgroup_destroy, - .exit = perf_cgroup_exit, - .attach = perf_cgroup_attach, -}; -#endif /* CONFIG_CGROUP_PERF */ -- cgit v1.1 From 48dbb6dc86ca5d1b2224937d774c7ba98bc3a485 Mon Sep 17 00:00:00 2001 From: Borislav Petkov Date: Tue, 3 May 2011 15:26:43 +0200 Subject: hw breakpoints: Move to kernel/events/ As part of the events sybsystem unification, relocate hw_breakpoint.c into its new destination. Cc: Frederic Weisbecker Signed-off-by: Borislav Petkov --- kernel/Makefile | 1 - kernel/events/Makefile | 3 +- kernel/events/hw_breakpoint.c | 659 ++++++++++++++++++++++++++++++++++++++++++ kernel/hw_breakpoint.c | 659 ------------------------------------------ 4 files changed, 661 insertions(+), 661 deletions(-) create mode 100644 kernel/events/hw_breakpoint.c delete mode 100644 kernel/hw_breakpoint.c (limited to 'kernel') diff --git a/kernel/Makefile b/kernel/Makefile index 7981530..e9cf191 100644 --- a/kernel/Makefile +++ b/kernel/Makefile @@ -105,7 +105,6 @@ obj-$(CONFIG_IRQ_WORK) += irq_work.o obj-$(CONFIG_PERF_EVENTS) += events/ -obj-$(CONFIG_HAVE_HW_BREAKPOINT) += hw_breakpoint.o obj-$(CONFIG_USER_RETURN_NOTIFIER) += user-return-notifier.o obj-$(CONFIG_PADATA) += padata.o obj-$(CONFIG_CRASH_DUMP) += crash_dump.o diff --git a/kernel/events/Makefile b/kernel/events/Makefile index 26c00e4..1ce23d3 100644 --- a/kernel/events/Makefile +++ b/kernel/events/Makefile @@ -2,4 +2,5 @@ ifdef CONFIG_FUNCTION_TRACER CFLAGS_REMOVE_core.o = -pg endif -obj-y += core.o +obj-y := core.o +obj-$(CONFIG_HAVE_HW_BREAKPOINT) += hw_breakpoint.o diff --git a/kernel/events/hw_breakpoint.c b/kernel/events/hw_breakpoint.c new file mode 100644 index 0000000..086adf2 --- /dev/null +++ b/kernel/events/hw_breakpoint.c @@ -0,0 +1,659 @@ +/* + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation; either version 2 of the License, or + * (at your option) any later version. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program; if not, write to the Free Software + * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. + * + * Copyright (C) 2007 Alan Stern + * Copyright (C) IBM Corporation, 2009 + * Copyright (C) 2009, Frederic Weisbecker + * + * Thanks to Ingo Molnar for his many suggestions. + * + * Authors: Alan Stern + * K.Prasad + * Frederic Weisbecker + */ + +/* + * HW_breakpoint: a unified kernel/user-space hardware breakpoint facility, + * using the CPU's debug registers. + * This file contains the arch-independent routines. + */ + +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include + +#include + + +/* + * Constraints data + */ + +/* Number of pinned cpu breakpoints in a cpu */ +static DEFINE_PER_CPU(unsigned int, nr_cpu_bp_pinned[TYPE_MAX]); + +/* Number of pinned task breakpoints in a cpu */ +static DEFINE_PER_CPU(unsigned int *, nr_task_bp_pinned[TYPE_MAX]); + +/* Number of non-pinned cpu/task breakpoints in a cpu */ +static DEFINE_PER_CPU(unsigned int, nr_bp_flexible[TYPE_MAX]); + +static int nr_slots[TYPE_MAX]; + +/* Keep track of the breakpoints attached to tasks */ +static LIST_HEAD(bp_task_head); + +static int constraints_initialized; + +/* Gather the number of total pinned and un-pinned bp in a cpuset */ +struct bp_busy_slots { + unsigned int pinned; + unsigned int flexible; +}; + +/* Serialize accesses to the above constraints */ +static DEFINE_MUTEX(nr_bp_mutex); + +__weak int hw_breakpoint_weight(struct perf_event *bp) +{ + return 1; +} + +static inline enum bp_type_idx find_slot_idx(struct perf_event *bp) +{ + if (bp->attr.bp_type & HW_BREAKPOINT_RW) + return TYPE_DATA; + + return TYPE_INST; +} + +/* + * Report the maximum number of pinned breakpoints a task + * have in this cpu + */ +static unsigned int max_task_bp_pinned(int cpu, enum bp_type_idx type) +{ + int i; + unsigned int *tsk_pinned = per_cpu(nr_task_bp_pinned[type], cpu); + + for (i = nr_slots[type] - 1; i >= 0; i--) { + if (tsk_pinned[i] > 0) + return i + 1; + } + + return 0; +} + +/* + * Count the number of breakpoints of the same type and same task. + * The given event must be not on the list. + */ +static int task_bp_pinned(struct perf_event *bp, enum bp_type_idx type) +{ + struct task_struct *tsk = bp->hw.bp_target; + struct perf_event *iter; + int count = 0; + + list_for_each_entry(iter, &bp_task_head, hw.bp_list) { + if (iter->hw.bp_target == tsk && find_slot_idx(iter) == type) + count += hw_breakpoint_weight(iter); + } + + return count; +} + +/* + * Report the number of pinned/un-pinned breakpoints we have in + * a given cpu (cpu > -1) or in all of them (cpu = -1). + */ +static void +fetch_bp_busy_slots(struct bp_busy_slots *slots, struct perf_event *bp, + enum bp_type_idx type) +{ + int cpu = bp->cpu; + struct task_struct *tsk = bp->hw.bp_target; + + if (cpu >= 0) { + slots->pinned = per_cpu(nr_cpu_bp_pinned[type], cpu); + if (!tsk) + slots->pinned += max_task_bp_pinned(cpu, type); + else + slots->pinned += task_bp_pinned(bp, type); + slots->flexible = per_cpu(nr_bp_flexible[type], cpu); + + return; + } + + for_each_online_cpu(cpu) { + unsigned int nr; + + nr = per_cpu(nr_cpu_bp_pinned[type], cpu); + if (!tsk) + nr += max_task_bp_pinned(cpu, type); + else + nr += task_bp_pinned(bp, type); + + if (nr > slots->pinned) + slots->pinned = nr; + + nr = per_cpu(nr_bp_flexible[type], cpu); + + if (nr > slots->flexible) + slots->flexible = nr; + } +} + +/* + * For now, continue to consider flexible as pinned, until we can + * ensure no flexible event can ever be scheduled before a pinned event + * in a same cpu. + */ +static void +fetch_this_slot(struct bp_busy_slots *slots, int weight) +{ + slots->pinned += weight; +} + +/* + * Add a pinned breakpoint for the given task in our constraint table + */ +static void toggle_bp_task_slot(struct perf_event *bp, int cpu, bool enable, + enum bp_type_idx type, int weight) +{ + unsigned int *tsk_pinned; + int old_count = 0; + int old_idx = 0; + int idx = 0; + + old_count = task_bp_pinned(bp, type); + old_idx = old_count - 1; + idx = old_idx + weight; + + /* tsk_pinned[n] is the number of tasks having n breakpoints */ + tsk_pinned = per_cpu(nr_task_bp_pinned[type], cpu); + if (enable) { + tsk_pinned[idx]++; + if (old_count > 0) + tsk_pinned[old_idx]--; + } else { + tsk_pinned[idx]--; + if (old_count > 0) + tsk_pinned[old_idx]++; + } +} + +/* + * Add/remove the given breakpoint in our constraint table + */ +static void +toggle_bp_slot(struct perf_event *bp, bool enable, enum bp_type_idx type, + int weight) +{ + int cpu = bp->cpu; + struct task_struct *tsk = bp->hw.bp_target; + + /* Pinned counter cpu profiling */ + if (!tsk) { + + if (enable) + per_cpu(nr_cpu_bp_pinned[type], bp->cpu) += weight; + else + per_cpu(nr_cpu_bp_pinned[type], bp->cpu) -= weight; + return; + } + + /* Pinned counter task profiling */ + + if (!enable) + list_del(&bp->hw.bp_list); + + if (cpu >= 0) { + toggle_bp_task_slot(bp, cpu, enable, type, weight); + } else { + for_each_online_cpu(cpu) + toggle_bp_task_slot(bp, cpu, enable, type, weight); + } + + if (enable) + list_add_tail(&bp->hw.bp_list, &bp_task_head); +} + +/* + * Function to perform processor-specific cleanup during unregistration + */ +__weak void arch_unregister_hw_breakpoint(struct perf_event *bp) +{ + /* + * A weak stub function here for those archs that don't define + * it inside arch/.../kernel/hw_breakpoint.c + */ +} + +/* + * Contraints to check before allowing this new breakpoint counter: + * + * == Non-pinned counter == (Considered as pinned for now) + * + * - If attached to a single cpu, check: + * + * (per_cpu(nr_bp_flexible, cpu) || (per_cpu(nr_cpu_bp_pinned, cpu) + * + max(per_cpu(nr_task_bp_pinned, cpu)))) < HBP_NUM + * + * -> If there are already non-pinned counters in this cpu, it means + * there is already a free slot for them. + * Otherwise, we check that the maximum number of per task + * breakpoints (for this cpu) plus the number of per cpu breakpoint + * (for this cpu) doesn't cover every registers. + * + * - If attached to every cpus, check: + * + * (per_cpu(nr_bp_flexible, *) || (max(per_cpu(nr_cpu_bp_pinned, *)) + * + max(per_cpu(nr_task_bp_pinned, *)))) < HBP_NUM + * + * -> This is roughly the same, except we check the number of per cpu + * bp for every cpu and we keep the max one. Same for the per tasks + * breakpoints. + * + * + * == Pinned counter == + * + * - If attached to a single cpu, check: + * + * ((per_cpu(nr_bp_flexible, cpu) > 1) + per_cpu(nr_cpu_bp_pinned, cpu) + * + max(per_cpu(nr_task_bp_pinned, cpu))) < HBP_NUM + * + * -> Same checks as before. But now the nr_bp_flexible, if any, must keep + * one register at least (or they will never be fed). + * + * - If attached to every cpus, check: + * + * ((per_cpu(nr_bp_flexible, *) > 1) + max(per_cpu(nr_cpu_bp_pinned, *)) + * + max(per_cpu(nr_task_bp_pinned, *))) < HBP_NUM + */ +static int __reserve_bp_slot(struct perf_event *bp) +{ + struct bp_busy_slots slots = {0}; + enum bp_type_idx type; + int weight; + + /* We couldn't initialize breakpoint constraints on boot */ + if (!constraints_initialized) + return -ENOMEM; + + /* Basic checks */ + if (bp->attr.bp_type == HW_BREAKPOINT_EMPTY || + bp->attr.bp_type == HW_BREAKPOINT_INVALID) + return -EINVAL; + + type = find_slot_idx(bp); + weight = hw_breakpoint_weight(bp); + + fetch_bp_busy_slots(&slots, bp, type); + /* + * Simulate the addition of this breakpoint to the constraints + * and see the result. + */ + fetch_this_slot(&slots, weight); + + /* Flexible counters need to keep at least one slot */ + if (slots.pinned + (!!slots.flexible) > nr_slots[type]) + return -ENOSPC; + + toggle_bp_slot(bp, true, type, weight); + + return 0; +} + +int reserve_bp_slot(struct perf_event *bp) +{ + int ret; + + mutex_lock(&nr_bp_mutex); + + ret = __reserve_bp_slot(bp); + + mutex_unlock(&nr_bp_mutex); + + return ret; +} + +static void __release_bp_slot(struct perf_event *bp) +{ + enum bp_type_idx type; + int weight; + + type = find_slot_idx(bp); + weight = hw_breakpoint_weight(bp); + toggle_bp_slot(bp, false, type, weight); +} + +void release_bp_slot(struct perf_event *bp) +{ + mutex_lock(&nr_bp_mutex); + + arch_unregister_hw_breakpoint(bp); + __release_bp_slot(bp); + + mutex_unlock(&nr_bp_mutex); +} + +/* + * Allow the kernel debugger to reserve breakpoint slots without + * taking a lock using the dbg_* variant of for the reserve and + * release breakpoint slots. + */ +int dbg_reserve_bp_slot(struct perf_event *bp) +{ + if (mutex_is_locked(&nr_bp_mutex)) + return -1; + + return __reserve_bp_slot(bp); +} + +int dbg_release_bp_slot(struct perf_event *bp) +{ + if (mutex_is_locked(&nr_bp_mutex)) + return -1; + + __release_bp_slot(bp); + + return 0; +} + +static int validate_hw_breakpoint(struct perf_event *bp) +{ + int ret; + + ret = arch_validate_hwbkpt_settings(bp); + if (ret) + return ret; + + if (arch_check_bp_in_kernelspace(bp)) { + if (bp->attr.exclude_kernel) + return -EINVAL; + /* + * Don't let unprivileged users set a breakpoint in the trap + * path to avoid trap recursion attacks. + */ + if (!capable(CAP_SYS_ADMIN)) + return -EPERM; + } + + return 0; +} + +int register_perf_hw_breakpoint(struct perf_event *bp) +{ + int ret; + + ret = reserve_bp_slot(bp); + if (ret) + return ret; + + ret = validate_hw_breakpoint(bp); + + /* if arch_validate_hwbkpt_settings() fails then release bp slot */ + if (ret) + release_bp_slot(bp); + + return ret; +} + +/** + * register_user_hw_breakpoint - register a hardware breakpoint for user space + * @attr: breakpoint attributes + * @triggered: callback to trigger when we hit the breakpoint + * @tsk: pointer to 'task_struct' of the process to which the address belongs + */ +struct perf_event * +register_user_hw_breakpoint(struct perf_event_attr *attr, + perf_overflow_handler_t triggered, + struct task_struct *tsk) +{ + return perf_event_create_kernel_counter(attr, -1, tsk, triggered); +} +EXPORT_SYMBOL_GPL(register_user_hw_breakpoint); + +/** + * modify_user_hw_breakpoint - modify a user-space hardware breakpoint + * @bp: the breakpoint structure to modify + * @attr: new breakpoint attributes + * @triggered: callback to trigger when we hit the breakpoint + * @tsk: pointer to 'task_struct' of the process to which the address belongs + */ +int modify_user_hw_breakpoint(struct perf_event *bp, struct perf_event_attr *attr) +{ + u64 old_addr = bp->attr.bp_addr; + u64 old_len = bp->attr.bp_len; + int old_type = bp->attr.bp_type; + int err = 0; + + perf_event_disable(bp); + + bp->attr.bp_addr = attr->bp_addr; + bp->attr.bp_type = attr->bp_type; + bp->attr.bp_len = attr->bp_len; + + if (attr->disabled) + goto end; + + err = validate_hw_breakpoint(bp); + if (!err) + perf_event_enable(bp); + + if (err) { + bp->attr.bp_addr = old_addr; + bp->attr.bp_type = old_type; + bp->attr.bp_len = old_len; + if (!bp->attr.disabled) + perf_event_enable(bp); + + return err; + } + +end: + bp->attr.disabled = attr->disabled; + + return 0; +} +EXPORT_SYMBOL_GPL(modify_user_hw_breakpoint); + +/** + * unregister_hw_breakpoint - unregister a user-space hardware breakpoint + * @bp: the breakpoint structure to unregister + */ +void unregister_hw_breakpoint(struct perf_event *bp) +{ + if (!bp) + return; + perf_event_release_kernel(bp); +} +EXPORT_SYMBOL_GPL(unregister_hw_breakpoint); + +/** + * register_wide_hw_breakpoint - register a wide breakpoint in the kernel + * @attr: breakpoint attributes + * @triggered: callback to trigger when we hit the breakpoint + * + * @return a set of per_cpu pointers to perf events + */ +struct perf_event * __percpu * +register_wide_hw_breakpoint(struct perf_event_attr *attr, + perf_overflow_handler_t triggered) +{ + struct perf_event * __percpu *cpu_events, **pevent, *bp; + long err; + int cpu; + + cpu_events = alloc_percpu(typeof(*cpu_events)); + if (!cpu_events) + return (void __percpu __force *)ERR_PTR(-ENOMEM); + + get_online_cpus(); + for_each_online_cpu(cpu) { + pevent = per_cpu_ptr(cpu_events, cpu); + bp = perf_event_create_kernel_counter(attr, cpu, NULL, triggered); + + *pevent = bp; + + if (IS_ERR(bp)) { + err = PTR_ERR(bp); + goto fail; + } + } + put_online_cpus(); + + return cpu_events; + +fail: + for_each_online_cpu(cpu) { + pevent = per_cpu_ptr(cpu_events, cpu); + if (IS_ERR(*pevent)) + break; + unregister_hw_breakpoint(*pevent); + } + put_online_cpus(); + + free_percpu(cpu_events); + return (void __percpu __force *)ERR_PTR(err); +} +EXPORT_SYMBOL_GPL(register_wide_hw_breakpoint); + +/** + * unregister_wide_hw_breakpoint - unregister a wide breakpoint in the kernel + * @cpu_events: the per cpu set of events to unregister + */ +void unregister_wide_hw_breakpoint(struct perf_event * __percpu *cpu_events) +{ + int cpu; + struct perf_event **pevent; + + for_each_possible_cpu(cpu) { + pevent = per_cpu_ptr(cpu_events, cpu); + unregister_hw_breakpoint(*pevent); + } + free_percpu(cpu_events); +} +EXPORT_SYMBOL_GPL(unregister_wide_hw_breakpoint); + +static struct notifier_block hw_breakpoint_exceptions_nb = { + .notifier_call = hw_breakpoint_exceptions_notify, + /* we need to be notified first */ + .priority = 0x7fffffff +}; + +static void bp_perf_event_destroy(struct perf_event *event) +{ + release_bp_slot(event); +} + +static int hw_breakpoint_event_init(struct perf_event *bp) +{ + int err; + + if (bp->attr.type != PERF_TYPE_BREAKPOINT) + return -ENOENT; + + err = register_perf_hw_breakpoint(bp); + if (err) + return err; + + bp->destroy = bp_perf_event_destroy; + + return 0; +} + +static int hw_breakpoint_add(struct perf_event *bp, int flags) +{ + if (!(flags & PERF_EF_START)) + bp->hw.state = PERF_HES_STOPPED; + + return arch_install_hw_breakpoint(bp); +} + +static void hw_breakpoint_del(struct perf_event *bp, int flags) +{ + arch_uninstall_hw_breakpoint(bp); +} + +static void hw_breakpoint_start(struct perf_event *bp, int flags) +{ + bp->hw.state = 0; +} + +static void hw_breakpoint_stop(struct perf_event *bp, int flags) +{ + bp->hw.state = PERF_HES_STOPPED; +} + +static struct pmu perf_breakpoint = { + .task_ctx_nr = perf_sw_context, /* could eventually get its own */ + + .event_init = hw_breakpoint_event_init, + .add = hw_breakpoint_add, + .del = hw_breakpoint_del, + .start = hw_breakpoint_start, + .stop = hw_breakpoint_stop, + .read = hw_breakpoint_pmu_read, +}; + +int __init init_hw_breakpoint(void) +{ + unsigned int **task_bp_pinned; + int cpu, err_cpu; + int i; + + for (i = 0; i < TYPE_MAX; i++) + nr_slots[i] = hw_breakpoint_slots(i); + + for_each_possible_cpu(cpu) { + for (i = 0; i < TYPE_MAX; i++) { + task_bp_pinned = &per_cpu(nr_task_bp_pinned[i], cpu); + *task_bp_pinned = kzalloc(sizeof(int) * nr_slots[i], + GFP_KERNEL); + if (!*task_bp_pinned) + goto err_alloc; + } + } + + constraints_initialized = 1; + + perf_pmu_register(&perf_breakpoint, "breakpoint", PERF_TYPE_BREAKPOINT); + + return register_die_notifier(&hw_breakpoint_exceptions_nb); + + err_alloc: + for_each_possible_cpu(err_cpu) { + if (err_cpu == cpu) + break; + for (i = 0; i < TYPE_MAX; i++) + kfree(per_cpu(nr_task_bp_pinned[i], cpu)); + } + + return -ENOMEM; +} + + diff --git a/kernel/hw_breakpoint.c b/kernel/hw_breakpoint.c deleted file mode 100644 index 086adf2..0000000 --- a/kernel/hw_breakpoint.c +++ /dev/null @@ -1,659 +0,0 @@ -/* - * This program is free software; you can redistribute it and/or modify - * it under the terms of the GNU General Public License as published by - * the Free Software Foundation; either version 2 of the License, or - * (at your option) any later version. - * - * This program is distributed in the hope that it will be useful, - * but WITHOUT ANY WARRANTY; without even the implied warranty of - * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the - * GNU General Public License for more details. - * - * You should have received a copy of the GNU General Public License - * along with this program; if not, write to the Free Software - * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. - * - * Copyright (C) 2007 Alan Stern - * Copyright (C) IBM Corporation, 2009 - * Copyright (C) 2009, Frederic Weisbecker - * - * Thanks to Ingo Molnar for his many suggestions. - * - * Authors: Alan Stern - * K.Prasad - * Frederic Weisbecker - */ - -/* - * HW_breakpoint: a unified kernel/user-space hardware breakpoint facility, - * using the CPU's debug registers. - * This file contains the arch-independent routines. - */ - -#include -#include -#include -#include -#include -#include -#include -#include -#include -#include -#include -#include -#include -#include - -#include - - -/* - * Constraints data - */ - -/* Number of pinned cpu breakpoints in a cpu */ -static DEFINE_PER_CPU(unsigned int, nr_cpu_bp_pinned[TYPE_MAX]); - -/* Number of pinned task breakpoints in a cpu */ -static DEFINE_PER_CPU(unsigned int *, nr_task_bp_pinned[TYPE_MAX]); - -/* Number of non-pinned cpu/task breakpoints in a cpu */ -static DEFINE_PER_CPU(unsigned int, nr_bp_flexible[TYPE_MAX]); - -static int nr_slots[TYPE_MAX]; - -/* Keep track of the breakpoints attached to tasks */ -static LIST_HEAD(bp_task_head); - -static int constraints_initialized; - -/* Gather the number of total pinned and un-pinned bp in a cpuset */ -struct bp_busy_slots { - unsigned int pinned; - unsigned int flexible; -}; - -/* Serialize accesses to the above constraints */ -static DEFINE_MUTEX(nr_bp_mutex); - -__weak int hw_breakpoint_weight(struct perf_event *bp) -{ - return 1; -} - -static inline enum bp_type_idx find_slot_idx(struct perf_event *bp) -{ - if (bp->attr.bp_type & HW_BREAKPOINT_RW) - return TYPE_DATA; - - return TYPE_INST; -} - -/* - * Report the maximum number of pinned breakpoints a task - * have in this cpu - */ -static unsigned int max_task_bp_pinned(int cpu, enum bp_type_idx type) -{ - int i; - unsigned int *tsk_pinned = per_cpu(nr_task_bp_pinned[type], cpu); - - for (i = nr_slots[type] - 1; i >= 0; i--) { - if (tsk_pinned[i] > 0) - return i + 1; - } - - return 0; -} - -/* - * Count the number of breakpoints of the same type and same task. - * The given event must be not on the list. - */ -static int task_bp_pinned(struct perf_event *bp, enum bp_type_idx type) -{ - struct task_struct *tsk = bp->hw.bp_target; - struct perf_event *iter; - int count = 0; - - list_for_each_entry(iter, &bp_task_head, hw.bp_list) { - if (iter->hw.bp_target == tsk && find_slot_idx(iter) == type) - count += hw_breakpoint_weight(iter); - } - - return count; -} - -/* - * Report the number of pinned/un-pinned breakpoints we have in - * a given cpu (cpu > -1) or in all of them (cpu = -1). - */ -static void -fetch_bp_busy_slots(struct bp_busy_slots *slots, struct perf_event *bp, - enum bp_type_idx type) -{ - int cpu = bp->cpu; - struct task_struct *tsk = bp->hw.bp_target; - - if (cpu >= 0) { - slots->pinned = per_cpu(nr_cpu_bp_pinned[type], cpu); - if (!tsk) - slots->pinned += max_task_bp_pinned(cpu, type); - else - slots->pinned += task_bp_pinned(bp, type); - slots->flexible = per_cpu(nr_bp_flexible[type], cpu); - - return; - } - - for_each_online_cpu(cpu) { - unsigned int nr; - - nr = per_cpu(nr_cpu_bp_pinned[type], cpu); - if (!tsk) - nr += max_task_bp_pinned(cpu, type); - else - nr += task_bp_pinned(bp, type); - - if (nr > slots->pinned) - slots->pinned = nr; - - nr = per_cpu(nr_bp_flexible[type], cpu); - - if (nr > slots->flexible) - slots->flexible = nr; - } -} - -/* - * For now, continue to consider flexible as pinned, until we can - * ensure no flexible event can ever be scheduled before a pinned event - * in a same cpu. - */ -static void -fetch_this_slot(struct bp_busy_slots *slots, int weight) -{ - slots->pinned += weight; -} - -/* - * Add a pinned breakpoint for the given task in our constraint table - */ -static void toggle_bp_task_slot(struct perf_event *bp, int cpu, bool enable, - enum bp_type_idx type, int weight) -{ - unsigned int *tsk_pinned; - int old_count = 0; - int old_idx = 0; - int idx = 0; - - old_count = task_bp_pinned(bp, type); - old_idx = old_count - 1; - idx = old_idx + weight; - - /* tsk_pinned[n] is the number of tasks having n breakpoints */ - tsk_pinned = per_cpu(nr_task_bp_pinned[type], cpu); - if (enable) { - tsk_pinned[idx]++; - if (old_count > 0) - tsk_pinned[old_idx]--; - } else { - tsk_pinned[idx]--; - if (old_count > 0) - tsk_pinned[old_idx]++; - } -} - -/* - * Add/remove the given breakpoint in our constraint table - */ -static void -toggle_bp_slot(struct perf_event *bp, bool enable, enum bp_type_idx type, - int weight) -{ - int cpu = bp->cpu; - struct task_struct *tsk = bp->hw.bp_target; - - /* Pinned counter cpu profiling */ - if (!tsk) { - - if (enable) - per_cpu(nr_cpu_bp_pinned[type], bp->cpu) += weight; - else - per_cpu(nr_cpu_bp_pinned[type], bp->cpu) -= weight; - return; - } - - /* Pinned counter task profiling */ - - if (!enable) - list_del(&bp->hw.bp_list); - - if (cpu >= 0) { - toggle_bp_task_slot(bp, cpu, enable, type, weight); - } else { - for_each_online_cpu(cpu) - toggle_bp_task_slot(bp, cpu, enable, type, weight); - } - - if (enable) - list_add_tail(&bp->hw.bp_list, &bp_task_head); -} - -/* - * Function to perform processor-specific cleanup during unregistration - */ -__weak void arch_unregister_hw_breakpoint(struct perf_event *bp) -{ - /* - * A weak stub function here for those archs that don't define - * it inside arch/.../kernel/hw_breakpoint.c - */ -} - -/* - * Contraints to check before allowing this new breakpoint counter: - * - * == Non-pinned counter == (Considered as pinned for now) - * - * - If attached to a single cpu, check: - * - * (per_cpu(nr_bp_flexible, cpu) || (per_cpu(nr_cpu_bp_pinned, cpu) - * + max(per_cpu(nr_task_bp_pinned, cpu)))) < HBP_NUM - * - * -> If there are already non-pinned counters in this cpu, it means - * there is already a free slot for them. - * Otherwise, we check that the maximum number of per task - * breakpoints (for this cpu) plus the number of per cpu breakpoint - * (for this cpu) doesn't cover every registers. - * - * - If attached to every cpus, check: - * - * (per_cpu(nr_bp_flexible, *) || (max(per_cpu(nr_cpu_bp_pinned, *)) - * + max(per_cpu(nr_task_bp_pinned, *)))) < HBP_NUM - * - * -> This is roughly the same, except we check the number of per cpu - * bp for every cpu and we keep the max one. Same for the per tasks - * breakpoints. - * - * - * == Pinned counter == - * - * - If attached to a single cpu, check: - * - * ((per_cpu(nr_bp_flexible, cpu) > 1) + per_cpu(nr_cpu_bp_pinned, cpu) - * + max(per_cpu(nr_task_bp_pinned, cpu))) < HBP_NUM - * - * -> Same checks as before. But now the nr_bp_flexible, if any, must keep - * one register at least (or they will never be fed). - * - * - If attached to every cpus, check: - * - * ((per_cpu(nr_bp_flexible, *) > 1) + max(per_cpu(nr_cpu_bp_pinned, *)) - * + max(per_cpu(nr_task_bp_pinned, *))) < HBP_NUM - */ -static int __reserve_bp_slot(struct perf_event *bp) -{ - struct bp_busy_slots slots = {0}; - enum bp_type_idx type; - int weight; - - /* We couldn't initialize breakpoint constraints on boot */ - if (!constraints_initialized) - return -ENOMEM; - - /* Basic checks */ - if (bp->attr.bp_type == HW_BREAKPOINT_EMPTY || - bp->attr.bp_type == HW_BREAKPOINT_INVALID) - return -EINVAL; - - type = find_slot_idx(bp); - weight = hw_breakpoint_weight(bp); - - fetch_bp_busy_slots(&slots, bp, type); - /* - * Simulate the addition of this breakpoint to the constraints - * and see the result. - */ - fetch_this_slot(&slots, weight); - - /* Flexible counters need to keep at least one slot */ - if (slots.pinned + (!!slots.flexible) > nr_slots[type]) - return -ENOSPC; - - toggle_bp_slot(bp, true, type, weight); - - return 0; -} - -int reserve_bp_slot(struct perf_event *bp) -{ - int ret; - - mutex_lock(&nr_bp_mutex); - - ret = __reserve_bp_slot(bp); - - mutex_unlock(&nr_bp_mutex); - - return ret; -} - -static void __release_bp_slot(struct perf_event *bp) -{ - enum bp_type_idx type; - int weight; - - type = find_slot_idx(bp); - weight = hw_breakpoint_weight(bp); - toggle_bp_slot(bp, false, type, weight); -} - -void release_bp_slot(struct perf_event *bp) -{ - mutex_lock(&nr_bp_mutex); - - arch_unregister_hw_breakpoint(bp); - __release_bp_slot(bp); - - mutex_unlock(&nr_bp_mutex); -} - -/* - * Allow the kernel debugger to reserve breakpoint slots without - * taking a lock using the dbg_* variant of for the reserve and - * release breakpoint slots. - */ -int dbg_reserve_bp_slot(struct perf_event *bp) -{ - if (mutex_is_locked(&nr_bp_mutex)) - return -1; - - return __reserve_bp_slot(bp); -} - -int dbg_release_bp_slot(struct perf_event *bp) -{ - if (mutex_is_locked(&nr_bp_mutex)) - return -1; - - __release_bp_slot(bp); - - return 0; -} - -static int validate_hw_breakpoint(struct perf_event *bp) -{ - int ret; - - ret = arch_validate_hwbkpt_settings(bp); - if (ret) - return ret; - - if (arch_check_bp_in_kernelspace(bp)) { - if (bp->attr.exclude_kernel) - return -EINVAL; - /* - * Don't let unprivileged users set a breakpoint in the trap - * path to avoid trap recursion attacks. - */ - if (!capable(CAP_SYS_ADMIN)) - return -EPERM; - } - - return 0; -} - -int register_perf_hw_breakpoint(struct perf_event *bp) -{ - int ret; - - ret = reserve_bp_slot(bp); - if (ret) - return ret; - - ret = validate_hw_breakpoint(bp); - - /* if arch_validate_hwbkpt_settings() fails then release bp slot */ - if (ret) - release_bp_slot(bp); - - return ret; -} - -/** - * register_user_hw_breakpoint - register a hardware breakpoint for user space - * @attr: breakpoint attributes - * @triggered: callback to trigger when we hit the breakpoint - * @tsk: pointer to 'task_struct' of the process to which the address belongs - */ -struct perf_event * -register_user_hw_breakpoint(struct perf_event_attr *attr, - perf_overflow_handler_t triggered, - struct task_struct *tsk) -{ - return perf_event_create_kernel_counter(attr, -1, tsk, triggered); -} -EXPORT_SYMBOL_GPL(register_user_hw_breakpoint); - -/** - * modify_user_hw_breakpoint - modify a user-space hardware breakpoint - * @bp: the breakpoint structure to modify - * @attr: new breakpoint attributes - * @triggered: callback to trigger when we hit the breakpoint - * @tsk: pointer to 'task_struct' of the process to which the address belongs - */ -int modify_user_hw_breakpoint(struct perf_event *bp, struct perf_event_attr *attr) -{ - u64 old_addr = bp->attr.bp_addr; - u64 old_len = bp->attr.bp_len; - int old_type = bp->attr.bp_type; - int err = 0; - - perf_event_disable(bp); - - bp->attr.bp_addr = attr->bp_addr; - bp->attr.bp_type = attr->bp_type; - bp->attr.bp_len = attr->bp_len; - - if (attr->disabled) - goto end; - - err = validate_hw_breakpoint(bp); - if (!err) - perf_event_enable(bp); - - if (err) { - bp->attr.bp_addr = old_addr; - bp->attr.bp_type = old_type; - bp->attr.bp_len = old_len; - if (!bp->attr.disabled) - perf_event_enable(bp); - - return err; - } - -end: - bp->attr.disabled = attr->disabled; - - return 0; -} -EXPORT_SYMBOL_GPL(modify_user_hw_breakpoint); - -/** - * unregister_hw_breakpoint - unregister a user-space hardware breakpoint - * @bp: the breakpoint structure to unregister - */ -void unregister_hw_breakpoint(struct perf_event *bp) -{ - if (!bp) - return; - perf_event_release_kernel(bp); -} -EXPORT_SYMBOL_GPL(unregister_hw_breakpoint); - -/** - * register_wide_hw_breakpoint - register a wide breakpoint in the kernel - * @attr: breakpoint attributes - * @triggered: callback to trigger when we hit the breakpoint - * - * @return a set of per_cpu pointers to perf events - */ -struct perf_event * __percpu * -register_wide_hw_breakpoint(struct perf_event_attr *attr, - perf_overflow_handler_t triggered) -{ - struct perf_event * __percpu *cpu_events, **pevent, *bp; - long err; - int cpu; - - cpu_events = alloc_percpu(typeof(*cpu_events)); - if (!cpu_events) - return (void __percpu __force *)ERR_PTR(-ENOMEM); - - get_online_cpus(); - for_each_online_cpu(cpu) { - pevent = per_cpu_ptr(cpu_events, cpu); - bp = perf_event_create_kernel_counter(attr, cpu, NULL, triggered); - - *pevent = bp; - - if (IS_ERR(bp)) { - err = PTR_ERR(bp); - goto fail; - } - } - put_online_cpus(); - - return cpu_events; - -fail: - for_each_online_cpu(cpu) { - pevent = per_cpu_ptr(cpu_events, cpu); - if (IS_ERR(*pevent)) - break; - unregister_hw_breakpoint(*pevent); - } - put_online_cpus(); - - free_percpu(cpu_events); - return (void __percpu __force *)ERR_PTR(err); -} -EXPORT_SYMBOL_GPL(register_wide_hw_breakpoint); - -/** - * unregister_wide_hw_breakpoint - unregister a wide breakpoint in the kernel - * @cpu_events: the per cpu set of events to unregister - */ -void unregister_wide_hw_breakpoint(struct perf_event * __percpu *cpu_events) -{ - int cpu; - struct perf_event **pevent; - - for_each_possible_cpu(cpu) { - pevent = per_cpu_ptr(cpu_events, cpu); - unregister_hw_breakpoint(*pevent); - } - free_percpu(cpu_events); -} -EXPORT_SYMBOL_GPL(unregister_wide_hw_breakpoint); - -static struct notifier_block hw_breakpoint_exceptions_nb = { - .notifier_call = hw_breakpoint_exceptions_notify, - /* we need to be notified first */ - .priority = 0x7fffffff -}; - -static void bp_perf_event_destroy(struct perf_event *event) -{ - release_bp_slot(event); -} - -static int hw_breakpoint_event_init(struct perf_event *bp) -{ - int err; - - if (bp->attr.type != PERF_TYPE_BREAKPOINT) - return -ENOENT; - - err = register_perf_hw_breakpoint(bp); - if (err) - return err; - - bp->destroy = bp_perf_event_destroy; - - return 0; -} - -static int hw_breakpoint_add(struct perf_event *bp, int flags) -{ - if (!(flags & PERF_EF_START)) - bp->hw.state = PERF_HES_STOPPED; - - return arch_install_hw_breakpoint(bp); -} - -static void hw_breakpoint_del(struct perf_event *bp, int flags) -{ - arch_uninstall_hw_breakpoint(bp); -} - -static void hw_breakpoint_start(struct perf_event *bp, int flags) -{ - bp->hw.state = 0; -} - -static void hw_breakpoint_stop(struct perf_event *bp, int flags) -{ - bp->hw.state = PERF_HES_STOPPED; -} - -static struct pmu perf_breakpoint = { - .task_ctx_nr = perf_sw_context, /* could eventually get its own */ - - .event_init = hw_breakpoint_event_init, - .add = hw_breakpoint_add, - .del = hw_breakpoint_del, - .start = hw_breakpoint_start, - .stop = hw_breakpoint_stop, - .read = hw_breakpoint_pmu_read, -}; - -int __init init_hw_breakpoint(void) -{ - unsigned int **task_bp_pinned; - int cpu, err_cpu; - int i; - - for (i = 0; i < TYPE_MAX; i++) - nr_slots[i] = hw_breakpoint_slots(i); - - for_each_possible_cpu(cpu) { - for (i = 0; i < TYPE_MAX; i++) { - task_bp_pinned = &per_cpu(nr_task_bp_pinned[i], cpu); - *task_bp_pinned = kzalloc(sizeof(int) * nr_slots[i], - GFP_KERNEL); - if (!*task_bp_pinned) - goto err_alloc; - } - } - - constraints_initialized = 1; - - perf_pmu_register(&perf_breakpoint, "breakpoint", PERF_TYPE_BREAKPOINT); - - return register_die_notifier(&hw_breakpoint_exceptions_nb); - - err_alloc: - for_each_possible_cpu(err_cpu) { - if (err_cpu == cpu) - break; - for (i = 0; i < TYPE_MAX; i++) - kfree(per_cpu(nr_task_bp_pinned[i], cpu)); - } - - return -ENOMEM; -} - - -- cgit v1.1 From e7e7ee2eab2080248084d71fe0a115ab745eb2aa Mon Sep 17 00:00:00 2001 From: Ingo Molnar Date: Wed, 4 May 2011 08:42:29 +0200 Subject: perf events: Clean up definitions and initializers, update copyrights Fix a few inconsistent style bits that were added over the past few months. Cc: Peter Zijlstra Link: http://lkml.kernel.org/n/tip-yv4hwf9yhnzoada8pcpb3a97@git.kernel.org Signed-off-by: Ingo Molnar --- kernel/events/core.c | 40 ++++++++++++++++++++-------------------- 1 file changed, 20 insertions(+), 20 deletions(-) (limited to 'kernel') diff --git a/kernel/events/core.c b/kernel/events/core.c index 440bc48..0fc34a3 100644 --- a/kernel/events/core.c +++ b/kernel/events/core.c @@ -2,8 +2,8 @@ * Performance events core code: * * Copyright (C) 2008 Thomas Gleixner - * Copyright (C) 2008-2009 Red Hat, Inc., Ingo Molnar - * Copyright (C) 2008-2009 Red Hat, Inc., Peter Zijlstra + * Copyright (C) 2008-2011 Red Hat, Inc., Ingo Molnar + * Copyright (C) 2008-2011 Red Hat, Inc., Peter Zijlstra * Copyright © 2009 Paul Mackerras, IBM Corp. * * For licensing details see kernel-base/COPYING @@ -39,10 +39,10 @@ #include struct remote_function_call { - struct task_struct *p; - int (*func)(void *info); - void *info; - int ret; + struct task_struct *p; + int (*func)(void *info); + void *info; + int ret; }; static void remote_function(void *data) @@ -76,10 +76,10 @@ static int task_function_call(struct task_struct *p, int (*func) (void *info), void *info) { struct remote_function_call data = { - .p = p, - .func = func, - .info = info, - .ret = -ESRCH, /* No such (running) process */ + .p = p, + .func = func, + .info = info, + .ret = -ESRCH, /* No such (running) process */ }; if (task_curr(p)) @@ -100,10 +100,10 @@ task_function_call(struct task_struct *p, int (*func) (void *info), void *info) static int cpu_function_call(int cpu, int (*func) (void *info), void *info) { struct remote_function_call data = { - .p = NULL, - .func = func, - .info = info, - .ret = -ENXIO, /* No such CPU */ + .p = NULL, + .func = func, + .info = info, + .ret = -ENXIO, /* No such CPU */ }; smp_call_function_single(cpu, remote_function, &data, 1); @@ -7445,11 +7445,11 @@ static void perf_cgroup_exit(struct cgroup_subsys *ss, struct cgroup *cgrp, } struct cgroup_subsys perf_subsys = { - .name = "perf_event", - .subsys_id = perf_subsys_id, - .create = perf_cgroup_create, - .destroy = perf_cgroup_destroy, - .exit = perf_cgroup_exit, - .attach = perf_cgroup_attach, + .name = "perf_event", + .subsys_id = perf_subsys_id, + .create = perf_cgroup_create, + .destroy = perf_cgroup_destroy, + .exit = perf_cgroup_exit, + .attach = perf_cgroup_attach, }; #endif /* CONFIG_CGROUP_PERF */ -- cgit v1.1 From 931aeeda0dca81152aec48f30be01e86a268bf89 Mon Sep 17 00:00:00 2001 From: Vladimir Davydov Date: Tue, 3 May 2011 22:31:07 +0400 Subject: sched: Remove unused 'this_best_prio arg' from balance_tasks() It's passed across multiple functions but is never really used, so remove it. Signed-off-by: Vladimir Davydov Cc: Peter Zijlstra Link: http://lkml.kernel.org/r/1304447467-29200-1-git-send-email-vdavydov@parallels.com Signed-off-by: Ingo Molnar --- kernel/sched_fair.c | 16 ++++++---------- 1 file changed, 6 insertions(+), 10 deletions(-) (limited to 'kernel') diff --git a/kernel/sched_fair.c b/kernel/sched_fair.c index 5280272..37f2262 100644 --- a/kernel/sched_fair.c +++ b/kernel/sched_fair.c @@ -2142,7 +2142,7 @@ static unsigned long balance_tasks(struct rq *this_rq, int this_cpu, struct rq *busiest, unsigned long max_load_move, struct sched_domain *sd, enum cpu_idle_type idle, int *all_pinned, - int *this_best_prio, struct cfs_rq *busiest_cfs_rq) + struct cfs_rq *busiest_cfs_rq) { int loops = 0, pulled = 0; long rem_load_move = max_load_move; @@ -2180,9 +2180,6 @@ balance_tasks(struct rq *this_rq, int this_cpu, struct rq *busiest, */ if (rem_load_move <= 0) break; - - if (p->prio < *this_best_prio) - *this_best_prio = p->prio; } out: /* @@ -2242,7 +2239,7 @@ static unsigned long load_balance_fair(struct rq *this_rq, int this_cpu, struct rq *busiest, unsigned long max_load_move, struct sched_domain *sd, enum cpu_idle_type idle, - int *all_pinned, int *this_best_prio) + int *all_pinned) { long rem_load_move = max_load_move; int busiest_cpu = cpu_of(busiest); @@ -2267,7 +2264,7 @@ load_balance_fair(struct rq *this_rq, int this_cpu, struct rq *busiest, rem_load = div_u64(rem_load, busiest_h_load + 1); moved_load = balance_tasks(this_rq, this_cpu, busiest, - rem_load, sd, idle, all_pinned, this_best_prio, + rem_load, sd, idle, all_pinned, busiest_cfs_rq); if (!moved_load) @@ -2293,11 +2290,11 @@ static unsigned long load_balance_fair(struct rq *this_rq, int this_cpu, struct rq *busiest, unsigned long max_load_move, struct sched_domain *sd, enum cpu_idle_type idle, - int *all_pinned, int *this_best_prio) + int *all_pinned) { return balance_tasks(this_rq, this_cpu, busiest, max_load_move, sd, idle, all_pinned, - this_best_prio, &busiest->cfs); + &busiest->cfs); } #endif @@ -2314,12 +2311,11 @@ static int move_tasks(struct rq *this_rq, int this_cpu, struct rq *busiest, int *all_pinned) { unsigned long total_load_moved = 0, load_moved; - int this_best_prio = this_rq->curr->prio; do { load_moved = load_balance_fair(this_rq, this_cpu, busiest, max_load_move - total_load_moved, - sd, idle, all_pinned, &this_best_prio); + sd, idle, all_pinned); total_load_moved += load_moved; -- cgit v1.1 From e05b2efb82596905ebfe88e8612ee81dec9b6592 Mon Sep 17 00:00:00 2001 From: john stultz Date: Wed, 4 May 2011 18:16:50 -0700 Subject: clocksource: Install completely before selecting Christian Hoffmann reported that the command line clocksource override with acpi_pm timer fails: Kernel command line: clocksource=acpi_pm hpet clockevent registered Switching to clocksource hpet Override clocksource acpi_pm is not HRT compatible. Cannot switch while in HRT/NOHZ mode. The watchdog code is what enables CLOCK_SOURCE_VALID_FOR_HRES, but we actually end up selecting the clocksource before we enqueue it into the watchdog list, so that's why we see the warning and fail to switch to acpi_pm timer as requested. That's particularly bad when we want to debug timekeeping related problems in early boot. Put the selection call last. Reported-by: Christian Hoffmann Signed-off-by: John Stultz Cc: stable@kernel.org # 32... Link: http://lkml.kernel.org/r/%3C1304558210.2943.24.camel%40work-vm%3E Signed-off-by: Thomas Gleixner --- kernel/time/clocksource.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) (limited to 'kernel') diff --git a/kernel/time/clocksource.c b/kernel/time/clocksource.c index 6519cf62..0e17c10 100644 --- a/kernel/time/clocksource.c +++ b/kernel/time/clocksource.c @@ -685,8 +685,8 @@ int __clocksource_register_scale(struct clocksource *cs, u32 scale, u32 freq) /* Add clocksource to the clcoksource list */ mutex_lock(&clocksource_mutex); clocksource_enqueue(cs); - clocksource_select(); clocksource_enqueue_watchdog(cs); + clocksource_select(); mutex_unlock(&clocksource_mutex); return 0; } @@ -706,8 +706,8 @@ int clocksource_register(struct clocksource *cs) mutex_lock(&clocksource_mutex); clocksource_enqueue(cs); - clocksource_select(); clocksource_enqueue_watchdog(cs); + clocksource_select(); mutex_unlock(&clocksource_mutex); return 0; } -- cgit v1.1 From a00e0d714fbded07a7a2254391ce9ed5a5cb9d82 Mon Sep 17 00:00:00 2001 From: "Paul E. McKenney" Date: Tue, 8 Feb 2011 17:14:39 -0800 Subject: rcu: Remove conditional compilation for RCU CPU stall warnings The RCU CPU stall warnings can now be controlled using the rcu_cpu_stall_suppress boot-time parameter or via the same parameter from sysfs. There is therefore no longer any reason to have kernel config parameters for this feature. This commit therefore removes the RCU_CPU_STALL_DETECTOR and RCU_CPU_STALL_DETECTOR_RUNNABLE kernel config parameters. The RCU_CPU_STALL_TIMEOUT parameter remains to allow the timeout to be tuned and the RCU_CPU_STALL_VERBOSE parameter remains to allow task-stall information to be suppressed if desired. Signed-off-by: Paul E. McKenney Reviewed-by: Josh Triplett --- kernel/rcutree.c | 26 +------------------------- kernel/rcutree.h | 12 ------------ kernel/rcutree_plugin.h | 12 ------------ 3 files changed, 1 insertion(+), 49 deletions(-) (limited to 'kernel') diff --git a/kernel/rcutree.c b/kernel/rcutree.c index dd4aea8..18f7a59 100644 --- a/kernel/rcutree.c +++ b/kernel/rcutree.c @@ -140,10 +140,8 @@ module_param(blimit, int, 0); module_param(qhimark, int, 0); module_param(qlowmark, int, 0); -#ifdef CONFIG_RCU_CPU_STALL_DETECTOR -int rcu_cpu_stall_suppress __read_mostly = RCU_CPU_STALL_SUPPRESS_INIT; +int rcu_cpu_stall_suppress __read_mostly; module_param(rcu_cpu_stall_suppress, int, 0644); -#endif /* #ifdef CONFIG_RCU_CPU_STALL_DETECTOR */ static void force_quiescent_state(struct rcu_state *rsp, int relaxed); static int rcu_pending(int cpu); @@ -450,8 +448,6 @@ static int rcu_implicit_dynticks_qs(struct rcu_data *rdp) #endif /* #else #ifdef CONFIG_NO_HZ */ -#ifdef CONFIG_RCU_CPU_STALL_DETECTOR - int rcu_cpu_stall_suppress __read_mostly; static void record_gp_stall_check_time(struct rcu_state *rsp) @@ -587,26 +583,6 @@ static void __init check_cpu_stall_init(void) atomic_notifier_chain_register(&panic_notifier_list, &rcu_panic_block); } -#else /* #ifdef CONFIG_RCU_CPU_STALL_DETECTOR */ - -static void record_gp_stall_check_time(struct rcu_state *rsp) -{ -} - -static void check_cpu_stall(struct rcu_state *rsp, struct rcu_data *rdp) -{ -} - -void rcu_cpu_stall_reset(void) -{ -} - -static void __init check_cpu_stall_init(void) -{ -} - -#endif /* #else #ifdef CONFIG_RCU_CPU_STALL_DETECTOR */ - /* * Update CPU-local rcu_data state to record the newly noticed grace period. * This is used both when we started the grace period and when we notice diff --git a/kernel/rcutree.h b/kernel/rcutree.h index e8f057e..e1a6663 100644 --- a/kernel/rcutree.h +++ b/kernel/rcutree.h @@ -254,7 +254,6 @@ struct rcu_data { #endif /* #else #ifdef CONFIG_NO_HZ */ #define RCU_JIFFIES_TILL_FORCE_QS 3 /* for rsp->jiffies_force_qs */ -#ifdef CONFIG_RCU_CPU_STALL_DETECTOR #ifdef CONFIG_PROVE_RCU #define RCU_STALL_DELAY_DELTA (5 * HZ) @@ -272,13 +271,6 @@ struct rcu_data { /* scheduling clock irq */ /* before ratting on them. */ -#ifdef CONFIG_RCU_CPU_STALL_DETECTOR_RUNNABLE -#define RCU_CPU_STALL_SUPPRESS_INIT 0 -#else -#define RCU_CPU_STALL_SUPPRESS_INIT 1 -#endif - -#endif /* #ifdef CONFIG_RCU_CPU_STALL_DETECTOR */ /* * RCU global state, including node hierarchy. This hierarchy is @@ -325,12 +317,10 @@ struct rcu_state { /* due to lock unavailable. */ unsigned long n_force_qs_ngp; /* Number of calls leaving */ /* due to no GP active. */ -#ifdef CONFIG_RCU_CPU_STALL_DETECTOR unsigned long gp_start; /* Time at which GP started, */ /* but in jiffies. */ unsigned long jiffies_stall; /* Time at which to check */ /* for CPU stalls. */ -#endif /* #ifdef CONFIG_RCU_CPU_STALL_DETECTOR */ char *name; /* Name of structure. */ }; @@ -366,11 +356,9 @@ static int rcu_preempted_readers(struct rcu_node *rnp); static void rcu_report_unblock_qs_rnp(struct rcu_node *rnp, unsigned long flags); #endif /* #ifdef CONFIG_HOTPLUG_CPU */ -#ifdef CONFIG_RCU_CPU_STALL_DETECTOR static void rcu_print_detail_task_stall(struct rcu_state *rsp); static void rcu_print_task_stall(struct rcu_node *rnp); static void rcu_preempt_stall_reset(void); -#endif /* #ifdef CONFIG_RCU_CPU_STALL_DETECTOR */ static void rcu_preempt_check_blocked_tasks(struct rcu_node *rnp); #ifdef CONFIG_HOTPLUG_CPU static int rcu_preempt_offline_tasks(struct rcu_state *rsp, diff --git a/kernel/rcutree_plugin.h b/kernel/rcutree_plugin.h index a363871..38426ef 100644 --- a/kernel/rcutree_plugin.h +++ b/kernel/rcutree_plugin.h @@ -54,10 +54,6 @@ static void __init rcu_bootup_announce_oddness(void) #ifdef CONFIG_RCU_TORTURE_TEST_RUNNABLE printk(KERN_INFO "\tRCU torture testing starts during boot.\n"); #endif -#ifndef CONFIG_RCU_CPU_STALL_DETECTOR - printk(KERN_INFO - "\tRCU-based detection of stalled CPUs is disabled.\n"); -#endif #if defined(CONFIG_TREE_PREEMPT_RCU) && !defined(CONFIG_RCU_CPU_STALL_VERBOSE) printk(KERN_INFO "\tVerbose stalled-CPUs detection is disabled.\n"); #endif @@ -356,8 +352,6 @@ void __rcu_read_unlock(void) } EXPORT_SYMBOL_GPL(__rcu_read_unlock); -#ifdef CONFIG_RCU_CPU_STALL_DETECTOR - #ifdef CONFIG_RCU_CPU_STALL_VERBOSE /* @@ -430,8 +424,6 @@ static void rcu_preempt_stall_reset(void) rcu_preempt_state.jiffies_stall = jiffies + ULONG_MAX / 2; } -#endif /* #ifdef CONFIG_RCU_CPU_STALL_DETECTOR */ - /* * Check that the list of blocked tasks for the newly completed grace * period is in fact empty. It is a serious bug to complete a grace @@ -862,8 +854,6 @@ static void rcu_report_unblock_qs_rnp(struct rcu_node *rnp, unsigned long flags) #endif /* #ifdef CONFIG_HOTPLUG_CPU */ -#ifdef CONFIG_RCU_CPU_STALL_DETECTOR - /* * Because preemptable RCU does not exist, we never have to check for * tasks blocked within RCU read-side critical sections. @@ -888,8 +878,6 @@ static void rcu_preempt_stall_reset(void) { } -#endif /* #ifdef CONFIG_RCU_CPU_STALL_DETECTOR */ - /* * Because there is no preemptable RCU, there can be no readers blocked, * so there is no need to check for blocked tasks. So check only for -- cgit v1.1 From e59fb3120becfb36b22ddb8bd27d065d3cdca499 Mon Sep 17 00:00:00 2001 From: "Paul E. McKenney" Date: Tue, 7 Sep 2010 10:38:22 -0700 Subject: rcu: Decrease memory-barrier usage based on semi-formal proof Commit d09b62d fixed grace-period synchronization, but left some smp_mb() invocations in rcu_process_callbacks() that are no longer needed, but sheer paranoia prevented them from being removed. This commit removes them and provides a proof of correctness in their absence. It also adds a memory barrier to rcu_report_qs_rsp() immediately before the update to rsp->completed in order to handle the theoretical possibility that the compiler or CPU might move massive quantities of code into a lock-based critical section. This also proves that the sheer paranoia was not entirely unjustified, at least from a theoretical point of view. In addition, the old dyntick-idle synchronization depended on the fact that grace periods were many milliseconds in duration, so that it could be assumed that no dyntick-idle CPU could reorder a memory reference across an entire grace period. Unfortunately for this design, the addition of expedited grace periods breaks this assumption, which has the unfortunate side-effect of requiring atomic operations in the functions that track dyntick-idle state for RCU. (There is some hope that the algorithms used in user-level RCU might be applied here, but some work is required to handle the NMIs that user-space applications can happily ignore. For the short term, better safe than sorry.) This proof assumes that neither compiler nor CPU will allow a lock acquisition and release to be reordered, as doing so can result in deadlock. The proof is as follows: 1. A given CPU declares a quiescent state under the protection of its leaf rcu_node's lock. 2. If there is more than one level of rcu_node hierarchy, the last CPU to declare a quiescent state will also acquire the ->lock of the next rcu_node up in the hierarchy, but only after releasing the lower level's lock. The acquisition of this lock clearly cannot occur prior to the acquisition of the leaf node's lock. 3. Step 2 repeats until we reach the root rcu_node structure. Please note again that only one lock is held at a time through this process. The acquisition of the root rcu_node's ->lock must occur after the release of that of the leaf rcu_node. 4. At this point, we set the ->completed field in the rcu_state structure in rcu_report_qs_rsp(). However, if the rcu_node hierarchy contains only one rcu_node, then in theory the code preceding the quiescent state could leak into the critical section. We therefore precede the update of ->completed with a memory barrier. All CPUs will therefore agree that any updates preceding any report of a quiescent state will have happened before the update of ->completed. 5. Regardless of whether a new grace period is needed, rcu_start_gp() will propagate the new value of ->completed to all of the leaf rcu_node structures, under the protection of each rcu_node's ->lock. If a new grace period is needed immediately, this propagation will occur in the same critical section that ->completed was set in, but courtesy of the memory barrier in #4 above, is still seen to follow any pre-quiescent-state activity. 6. When a given CPU invokes __rcu_process_gp_end(), it becomes aware of the end of the old grace period and therefore makes any RCU callbacks that were waiting on that grace period eligible for invocation. If this CPU is the same one that detected the end of the grace period, and if there is but a single rcu_node in the hierarchy, we will still be in the single critical section. In this case, the memory barrier in step #4 guarantees that all callbacks will be seen to execute after each CPU's quiescent state. On the other hand, if this is a different CPU, it will acquire the leaf rcu_node's ->lock, and will again be serialized after each CPU's quiescent state for the old grace period. On the strength of this proof, this commit therefore removes the memory barriers from rcu_process_callbacks() and adds one to rcu_report_qs_rsp(). The effect is to reduce the number of memory barriers by one and to reduce the frequency of execution from about once per scheduling tick per CPU to once per grace period. Signed-off-by: Paul E. McKenney Reviewed-by: Josh Triplett --- kernel/rcutree.c | 130 +++++++++++++++++++++--------------------------- kernel/rcutree.h | 9 ++-- kernel/rcutree_plugin.h | 7 ++- kernel/rcutree_trace.c | 12 ++--- 4 files changed, 68 insertions(+), 90 deletions(-) (limited to 'kernel') diff --git a/kernel/rcutree.c b/kernel/rcutree.c index 18f7a59..90104a1 100644 --- a/kernel/rcutree.c +++ b/kernel/rcutree.c @@ -128,7 +128,7 @@ void rcu_note_context_switch(int cpu) #ifdef CONFIG_NO_HZ DEFINE_PER_CPU(struct rcu_dynticks, rcu_dynticks) = { .dynticks_nesting = 1, - .dynticks = 1, + .dynticks = ATOMIC_INIT(1), }; #endif /* #ifdef CONFIG_NO_HZ */ @@ -262,13 +262,25 @@ void rcu_enter_nohz(void) unsigned long flags; struct rcu_dynticks *rdtp; - smp_mb(); /* CPUs seeing ++ must see prior RCU read-side crit sects */ local_irq_save(flags); rdtp = &__get_cpu_var(rcu_dynticks); - rdtp->dynticks++; - rdtp->dynticks_nesting--; - WARN_ON_ONCE(rdtp->dynticks & 0x1); + if (--rdtp->dynticks_nesting) { + local_irq_restore(flags); + return; + } + /* CPUs seeing atomic_inc() must see prior RCU read-side crit sects */ + smp_mb__before_atomic_inc(); /* See above. */ + atomic_inc(&rdtp->dynticks); + smp_mb__after_atomic_inc(); /* Force ordering with next sojourn. */ + WARN_ON_ONCE(atomic_read(&rdtp->dynticks) & 0x1); local_irq_restore(flags); + + /* If the interrupt queued a callback, get out of dyntick mode. */ + if (in_irq() && + (__get_cpu_var(rcu_sched_data).nxtlist || + __get_cpu_var(rcu_bh_data).nxtlist || + rcu_preempt_needs_cpu(smp_processor_id()))) + set_need_resched(); } /* @@ -284,11 +296,16 @@ void rcu_exit_nohz(void) local_irq_save(flags); rdtp = &__get_cpu_var(rcu_dynticks); - rdtp->dynticks++; - rdtp->dynticks_nesting++; - WARN_ON_ONCE(!(rdtp->dynticks & 0x1)); + if (rdtp->dynticks_nesting++) { + local_irq_restore(flags); + return; + } + smp_mb__before_atomic_inc(); /* Force ordering w/previous sojourn. */ + atomic_inc(&rdtp->dynticks); + /* CPUs seeing atomic_inc() must see later RCU read-side crit sects */ + smp_mb__after_atomic_inc(); /* See above. */ + WARN_ON_ONCE(!(atomic_read(&rdtp->dynticks) & 0x1)); local_irq_restore(flags); - smp_mb(); /* CPUs seeing ++ must see later RCU read-side crit sects */ } /** @@ -302,11 +319,15 @@ void rcu_nmi_enter(void) { struct rcu_dynticks *rdtp = &__get_cpu_var(rcu_dynticks); - if (rdtp->dynticks & 0x1) + if (rdtp->dynticks_nmi_nesting == 0 && + (atomic_read(&rdtp->dynticks) & 0x1)) return; - rdtp->dynticks_nmi++; - WARN_ON_ONCE(!(rdtp->dynticks_nmi & 0x1)); - smp_mb(); /* CPUs seeing ++ must see later RCU read-side crit sects */ + rdtp->dynticks_nmi_nesting++; + smp_mb__before_atomic_inc(); /* Force delay from prior write. */ + atomic_inc(&rdtp->dynticks); + /* CPUs seeing atomic_inc() must see later RCU read-side crit sects */ + smp_mb__after_atomic_inc(); /* See above. */ + WARN_ON_ONCE(!(atomic_read(&rdtp->dynticks) & 0x1)); } /** @@ -320,11 +341,14 @@ void rcu_nmi_exit(void) { struct rcu_dynticks *rdtp = &__get_cpu_var(rcu_dynticks); - if (rdtp->dynticks & 0x1) + if (rdtp->dynticks_nmi_nesting == 0 || + --rdtp->dynticks_nmi_nesting != 0) return; - smp_mb(); /* CPUs seeing ++ must see prior RCU read-side crit sects */ - rdtp->dynticks_nmi++; - WARN_ON_ONCE(rdtp->dynticks_nmi & 0x1); + /* CPUs seeing atomic_inc() must see prior RCU read-side crit sects */ + smp_mb__before_atomic_inc(); /* See above. */ + atomic_inc(&rdtp->dynticks); + smp_mb__after_atomic_inc(); /* Force delay to next write. */ + WARN_ON_ONCE(atomic_read(&rdtp->dynticks) & 0x1); } /** @@ -335,13 +359,7 @@ void rcu_nmi_exit(void) */ void rcu_irq_enter(void) { - struct rcu_dynticks *rdtp = &__get_cpu_var(rcu_dynticks); - - if (rdtp->dynticks_nesting++) - return; - rdtp->dynticks++; - WARN_ON_ONCE(!(rdtp->dynticks & 0x1)); - smp_mb(); /* CPUs seeing ++ must see later RCU read-side crit sects */ + rcu_exit_nohz(); } /** @@ -353,18 +371,7 @@ void rcu_irq_enter(void) */ void rcu_irq_exit(void) { - struct rcu_dynticks *rdtp = &__get_cpu_var(rcu_dynticks); - - if (--rdtp->dynticks_nesting) - return; - smp_mb(); /* CPUs seeing ++ must see prior RCU read-side crit sects */ - rdtp->dynticks++; - WARN_ON_ONCE(rdtp->dynticks & 0x1); - - /* If the interrupt queued a callback, get out of dyntick mode. */ - if (__this_cpu_read(rcu_sched_data.nxtlist) || - __this_cpu_read(rcu_bh_data.nxtlist)) - set_need_resched(); + rcu_enter_nohz(); } #ifdef CONFIG_SMP @@ -376,19 +383,8 @@ void rcu_irq_exit(void) */ static int dyntick_save_progress_counter(struct rcu_data *rdp) { - int ret; - int snap; - int snap_nmi; - - snap = rdp->dynticks->dynticks; - snap_nmi = rdp->dynticks->dynticks_nmi; - smp_mb(); /* Order sampling of snap with end of grace period. */ - rdp->dynticks_snap = snap; - rdp->dynticks_nmi_snap = snap_nmi; - ret = ((snap & 0x1) == 0) && ((snap_nmi & 0x1) == 0); - if (ret) - rdp->dynticks_fqs++; - return ret; + rdp->dynticks_snap = atomic_add_return(0, &rdp->dynticks->dynticks); + return 0; } /* @@ -399,16 +395,11 @@ static int dyntick_save_progress_counter(struct rcu_data *rdp) */ static int rcu_implicit_dynticks_qs(struct rcu_data *rdp) { - long curr; - long curr_nmi; - long snap; - long snap_nmi; + unsigned long curr; + unsigned long snap; - curr = rdp->dynticks->dynticks; - snap = rdp->dynticks_snap; - curr_nmi = rdp->dynticks->dynticks_nmi; - snap_nmi = rdp->dynticks_nmi_snap; - smp_mb(); /* force ordering with cpu entering/leaving dynticks. */ + curr = (unsigned long)atomic_add_return(0, &rdp->dynticks->dynticks); + snap = (unsigned long)rdp->dynticks_snap; /* * If the CPU passed through or entered a dynticks idle phase with @@ -418,8 +409,7 @@ static int rcu_implicit_dynticks_qs(struct rcu_data *rdp) * read-side critical section that started before the beginning * of the current RCU grace period. */ - if ((curr != snap || (curr & 0x1) == 0) && - (curr_nmi != snap_nmi || (curr_nmi & 0x1) == 0)) { + if ((curr & 0x1) == 0 || ULONG_CMP_GE(curr, snap + 2)) { rdp->dynticks_fqs++; return 1; } @@ -841,6 +831,12 @@ static void rcu_report_qs_rsp(struct rcu_state *rsp, unsigned long flags) __releases(rcu_get_root(rsp)->lock) { WARN_ON_ONCE(!rcu_gp_in_progress(rsp)); + + /* + * Ensure that all grace-period and pre-grace-period activity + * is seen before the assignment to rsp->completed. + */ + smp_mb(); /* See above block comment. */ rsp->completed = rsp->gpnum; rsp->signaled = RCU_GP_IDLE; rcu_start_gp(rsp, flags); /* releases root node's rnp->lock. */ @@ -1367,25 +1363,11 @@ __rcu_process_callbacks(struct rcu_state *rsp, struct rcu_data *rdp) */ static void rcu_process_callbacks(struct softirq_action *unused) { - /* - * Memory references from any prior RCU read-side critical sections - * executed by the interrupted code must be seen before any RCU - * grace-period manipulations below. - */ - smp_mb(); /* See above block comment. */ - __rcu_process_callbacks(&rcu_sched_state, &__get_cpu_var(rcu_sched_data)); __rcu_process_callbacks(&rcu_bh_state, &__get_cpu_var(rcu_bh_data)); rcu_preempt_process_callbacks(); - /* - * Memory references from any later RCU read-side critical sections - * executed by the interrupted code must be seen after any RCU - * grace-period manipulations above. - */ - smp_mb(); /* See above block comment. */ - /* If we are last CPU on way to dyntick-idle mode, accelerate it. */ rcu_needs_cpu_flush(); } diff --git a/kernel/rcutree.h b/kernel/rcutree.h index e1a6663..bd891de 100644 --- a/kernel/rcutree.h +++ b/kernel/rcutree.h @@ -84,11 +84,9 @@ * Dynticks per-CPU state. */ struct rcu_dynticks { - int dynticks_nesting; /* Track nesting level, sort of. */ - int dynticks; /* Even value for dynticks-idle, else odd. */ - int dynticks_nmi; /* Even value for either dynticks-idle or */ - /* not in nmi handler, else odd. So this */ - /* remains even for nmi from irq handler. */ + int dynticks_nesting; /* Track irq/process nesting level. */ + int dynticks_nmi_nesting; /* Track NMI nesting level. */ + atomic_t dynticks; /* Even value for dynticks-idle, else odd. */ }; /* @@ -218,7 +216,6 @@ struct rcu_data { /* 3) dynticks interface. */ struct rcu_dynticks *dynticks; /* Shared per-CPU dynticks state. */ int dynticks_snap; /* Per-GP tracking for dynticks. */ - int dynticks_nmi_snap; /* Per-GP tracking for dynticks_nmi. */ #endif /* #ifdef CONFIG_NO_HZ */ /* 4) reasons this CPU needed to be kicked by force_quiescent_state */ diff --git a/kernel/rcutree_plugin.h b/kernel/rcutree_plugin.h index 38426ef..764b5fc 100644 --- a/kernel/rcutree_plugin.h +++ b/kernel/rcutree_plugin.h @@ -1182,7 +1182,6 @@ int rcu_needs_cpu(int cpu) { int c = 0; int snap; - int snap_nmi; int thatcpu; /* Check for being in the holdoff period. */ @@ -1193,10 +1192,10 @@ int rcu_needs_cpu(int cpu) for_each_online_cpu(thatcpu) { if (thatcpu == cpu) continue; - snap = per_cpu(rcu_dynticks, thatcpu).dynticks; - snap_nmi = per_cpu(rcu_dynticks, thatcpu).dynticks_nmi; + snap = atomic_add_return(0, &per_cpu(rcu_dynticks, + thatcpu).dynticks); smp_mb(); /* Order sampling of snap with end of grace period. */ - if (((snap & 0x1) != 0) || ((snap_nmi & 0x1) != 0)) { + if ((snap & 0x1) != 0) { per_cpu(rcu_dyntick_drain, cpu) = 0; per_cpu(rcu_dyntick_holdoff, cpu) = jiffies - 1; return rcu_needs_cpu_quick_check(cpu); diff --git a/kernel/rcutree_trace.c b/kernel/rcutree_trace.c index c8e9785..4a21ca5 100644 --- a/kernel/rcutree_trace.c +++ b/kernel/rcutree_trace.c @@ -57,10 +57,10 @@ static void print_one_rcu_data(struct seq_file *m, struct rcu_data *rdp) rdp->passed_quiesc, rdp->passed_quiesc_completed, rdp->qs_pending); #ifdef CONFIG_NO_HZ - seq_printf(m, " dt=%d/%d dn=%d df=%lu", - rdp->dynticks->dynticks, + seq_printf(m, " dt=%d/%d/%d df=%lu", + atomic_read(&rdp->dynticks->dynticks), rdp->dynticks->dynticks_nesting, - rdp->dynticks->dynticks_nmi, + rdp->dynticks->dynticks_nmi_nesting, rdp->dynticks_fqs); #endif /* #ifdef CONFIG_NO_HZ */ seq_printf(m, " of=%lu ri=%lu", rdp->offline_fqs, rdp->resched_ipi); @@ -115,9 +115,9 @@ static void print_one_rcu_data_csv(struct seq_file *m, struct rcu_data *rdp) rdp->qs_pending); #ifdef CONFIG_NO_HZ seq_printf(m, ",%d,%d,%d,%lu", - rdp->dynticks->dynticks, + atomic_read(&rdp->dynticks->dynticks), rdp->dynticks->dynticks_nesting, - rdp->dynticks->dynticks_nmi, + rdp->dynticks->dynticks_nmi_nesting, rdp->dynticks_fqs); #endif /* #ifdef CONFIG_NO_HZ */ seq_printf(m, ",%lu,%lu", rdp->offline_fqs, rdp->resched_ipi); @@ -130,7 +130,7 @@ static int show_rcudata_csv(struct seq_file *m, void *unused) { seq_puts(m, "\"CPU\",\"Online?\",\"c\",\"g\",\"pq\",\"pqc\",\"pq\","); #ifdef CONFIG_NO_HZ - seq_puts(m, "\"dt\",\"dt nesting\",\"dn\",\"df\","); + seq_puts(m, "\"dt\",\"dt nesting\",\"dt NMI nesting\",\"df\","); #endif /* #ifdef CONFIG_NO_HZ */ seq_puts(m, "\"of\",\"ri\",\"ql\",\"b\",\"ci\",\"co\",\"ca\"\n"); #ifdef CONFIG_TREE_PREEMPT_RCU -- cgit v1.1 From 12f5f524cafef3ab689929b118f2dfb8bf2be321 Mon Sep 17 00:00:00 2001 From: "Paul E. McKenney" Date: Mon, 29 Nov 2010 21:56:39 -0800 Subject: rcu: merge TREE_PREEPT_RCU blocked_tasks[] lists Combine the current TREE_PREEMPT_RCU ->blocked_tasks[] lists in the rcu_node structure into a single ->blkd_tasks list with ->gp_tasks and ->exp_tasks tail pointers. This is in preparation for RCU priority boosting, which will add a third dimension to the combinatorial explosion in the ->blocked_tasks[] case, but simply a third pointer in the new ->blkd_tasks case. Also update documentation to reflect blocked_tasks[] merge Signed-off-by: Paul E. McKenney Signed-off-by: Paul E. McKenney Reviewed-by: Josh Triplett --- kernel/rcutree.c | 5 +- kernel/rcutree.h | 21 +++++-- kernel/rcutree_plugin.h | 163 ++++++++++++++++++++++++++++-------------------- kernel/rcutree_trace.c | 11 ++-- 4 files changed, 117 insertions(+), 83 deletions(-) (limited to 'kernel') diff --git a/kernel/rcutree.c b/kernel/rcutree.c index 90104a1..0ac1cc0 100644 --- a/kernel/rcutree.c +++ b/kernel/rcutree.c @@ -1901,10 +1901,7 @@ static void __init rcu_init_one(struct rcu_state *rsp, j / rsp->levelspread[i - 1]; } rnp->level = i; - INIT_LIST_HEAD(&rnp->blocked_tasks[0]); - INIT_LIST_HEAD(&rnp->blocked_tasks[1]); - INIT_LIST_HEAD(&rnp->blocked_tasks[2]); - INIT_LIST_HEAD(&rnp->blocked_tasks[3]); + INIT_LIST_HEAD(&rnp->blkd_tasks); } } diff --git a/kernel/rcutree.h b/kernel/rcutree.h index bd891de..5a439c1 100644 --- a/kernel/rcutree.h +++ b/kernel/rcutree.h @@ -107,7 +107,7 @@ struct rcu_node { /* an rcu_data structure, otherwise, each */ /* bit corresponds to a child rcu_node */ /* structure. */ - unsigned long expmask; /* Groups that have ->blocked_tasks[] */ + unsigned long expmask; /* Groups that have ->blkd_tasks */ /* elements that need to drain to allow the */ /* current expedited grace period to */ /* complete (only for TREE_PREEMPT_RCU). */ @@ -120,11 +120,20 @@ struct rcu_node { u8 grpnum; /* CPU/group number for next level up. */ u8 level; /* root is at level 0. */ struct rcu_node *parent; - struct list_head blocked_tasks[4]; - /* Tasks blocked in RCU read-side critsect. */ - /* Grace period number (->gpnum) x blocked */ - /* by tasks on the (x & 0x1) element of the */ - /* blocked_tasks[] array. */ + struct list_head blkd_tasks; + /* Tasks blocked in RCU read-side critical */ + /* section. Tasks are placed at the head */ + /* of this list and age towards the tail. */ + struct list_head *gp_tasks; + /* Pointer to the first task blocking the */ + /* current grace period, or NULL if there */ + /* is no such task. */ + struct list_head *exp_tasks; + /* Pointer to the first task blocking the */ + /* current expedited grace period, or NULL */ + /* if there is no such task. If there */ + /* is no current expedited grace period, */ + /* then there can cannot be any such task. */ } ____cacheline_internodealigned_in_smp; /* diff --git a/kernel/rcutree_plugin.h b/kernel/rcutree_plugin.h index 764b5fc..774f010 100644 --- a/kernel/rcutree_plugin.h +++ b/kernel/rcutree_plugin.h @@ -130,12 +130,12 @@ static void rcu_preempt_qs(int cpu) * We have entered the scheduler, and the current task might soon be * context-switched away from. If this task is in an RCU read-side * critical section, we will no longer be able to rely on the CPU to - * record that fact, so we enqueue the task on the appropriate entry - * of the blocked_tasks[] array. The task will dequeue itself when - * it exits the outermost enclosing RCU read-side critical section. - * Therefore, the current grace period cannot be permitted to complete - * until the blocked_tasks[] entry indexed by the low-order bit of - * rnp->gpnum empties. + * record that fact, so we enqueue the task on the blkd_tasks list. + * The task will dequeue itself when it exits the outermost enclosing + * RCU read-side critical section. Therefore, the current grace period + * cannot be permitted to complete until the blkd_tasks list entries + * predating the current grace period drain, in other words, until + * rnp->gp_tasks becomes NULL. * * Caller must disable preemption. */ @@ -143,7 +143,6 @@ static void rcu_preempt_note_context_switch(int cpu) { struct task_struct *t = current; unsigned long flags; - int phase; struct rcu_data *rdp; struct rcu_node *rnp; @@ -165,15 +164,26 @@ static void rcu_preempt_note_context_switch(int cpu) * (i.e., this CPU has not yet passed through a quiescent * state for the current grace period), then as long * as that task remains queued, the current grace period - * cannot end. + * cannot end. Note that there is some uncertainty as + * to exactly when the current grace period started. + * We take a conservative approach, which can result + * in unnecessarily waiting on tasks that started very + * slightly after the current grace period began. C'est + * la vie!!! * * But first, note that the current CPU must still be * on line! */ WARN_ON_ONCE((rdp->grpmask & rnp->qsmaskinit) == 0); WARN_ON_ONCE(!list_empty(&t->rcu_node_entry)); - phase = (rnp->gpnum + !(rnp->qsmask & rdp->grpmask)) & 0x1; - list_add(&t->rcu_node_entry, &rnp->blocked_tasks[phase]); + if ((rnp->qsmask & rdp->grpmask) && rnp->gp_tasks != NULL) { + list_add(&t->rcu_node_entry, rnp->gp_tasks->prev); + rnp->gp_tasks = &t->rcu_node_entry; + } else { + list_add(&t->rcu_node_entry, &rnp->blkd_tasks); + if (rnp->qsmask & rdp->grpmask) + rnp->gp_tasks = &t->rcu_node_entry; + } raw_spin_unlock_irqrestore(&rnp->lock, flags); } @@ -210,10 +220,7 @@ EXPORT_SYMBOL_GPL(__rcu_read_lock); */ static int rcu_preempted_readers(struct rcu_node *rnp) { - int phase = rnp->gpnum & 0x1; - - return !list_empty(&rnp->blocked_tasks[phase]) || - !list_empty(&rnp->blocked_tasks[phase + 2]); + return rnp->gp_tasks != NULL; } /* @@ -253,6 +260,21 @@ static void rcu_report_unblock_qs_rnp(struct rcu_node *rnp, unsigned long flags) } /* + * Advance a ->blkd_tasks-list pointer to the next entry, instead + * returning NULL if at the end of the list. + */ +static struct list_head *rcu_next_node_entry(struct task_struct *t, + struct rcu_node *rnp) +{ + struct list_head *np; + + np = t->rcu_node_entry.next; + if (np == &rnp->blkd_tasks) + np = NULL; + return np; +} + +/* * Handle special cases during rcu_read_unlock(), such as needing to * notify RCU core processing or task having blocked during the RCU * read-side critical section. @@ -262,6 +284,7 @@ static void rcu_read_unlock_special(struct task_struct *t) int empty; int empty_exp; unsigned long flags; + struct list_head *np; struct rcu_node *rnp; int special; @@ -305,7 +328,12 @@ static void rcu_read_unlock_special(struct task_struct *t) empty = !rcu_preempted_readers(rnp); empty_exp = !rcu_preempted_readers_exp(rnp); smp_mb(); /* ensure expedited fastpath sees end of RCU c-s. */ + np = rcu_next_node_entry(t, rnp); list_del_init(&t->rcu_node_entry); + if (&t->rcu_node_entry == rnp->gp_tasks) + rnp->gp_tasks = np; + if (&t->rcu_node_entry == rnp->exp_tasks) + rnp->exp_tasks = np; t->rcu_blocked_node = NULL; /* @@ -361,18 +389,16 @@ EXPORT_SYMBOL_GPL(__rcu_read_unlock); static void rcu_print_detail_task_stall_rnp(struct rcu_node *rnp) { unsigned long flags; - struct list_head *lp; - int phase; struct task_struct *t; - if (rcu_preempted_readers(rnp)) { - raw_spin_lock_irqsave(&rnp->lock, flags); - phase = rnp->gpnum & 0x1; - lp = &rnp->blocked_tasks[phase]; - list_for_each_entry(t, lp, rcu_node_entry) - sched_show_task(t); - raw_spin_unlock_irqrestore(&rnp->lock, flags); - } + if (!rcu_preempted_readers(rnp)) + return; + raw_spin_lock_irqsave(&rnp->lock, flags); + t = list_entry(rnp->gp_tasks, + struct task_struct, rcu_node_entry); + list_for_each_entry_continue(t, &rnp->blkd_tasks, rcu_node_entry) + sched_show_task(t); + raw_spin_unlock_irqrestore(&rnp->lock, flags); } /* @@ -402,16 +428,14 @@ static void rcu_print_detail_task_stall(struct rcu_state *rsp) */ static void rcu_print_task_stall(struct rcu_node *rnp) { - struct list_head *lp; - int phase; struct task_struct *t; - if (rcu_preempted_readers(rnp)) { - phase = rnp->gpnum & 0x1; - lp = &rnp->blocked_tasks[phase]; - list_for_each_entry(t, lp, rcu_node_entry) - printk(" P%d", t->pid); - } + if (!rcu_preempted_readers(rnp)) + return; + t = list_entry(rnp->gp_tasks, + struct task_struct, rcu_node_entry); + list_for_each_entry_continue(t, &rnp->blkd_tasks, rcu_node_entry) + printk(" P%d", t->pid); } /* @@ -430,10 +454,15 @@ static void rcu_preempt_stall_reset(void) * period that still has RCU readers blocked! This function must be * invoked -before- updating this rnp's ->gpnum, and the rnp's ->lock * must be held by the caller. + * + * Also, if there are blocked tasks on the list, they automatically + * block the newly created grace period, so set up ->gp_tasks accordingly. */ static void rcu_preempt_check_blocked_tasks(struct rcu_node *rnp) { WARN_ON_ONCE(rcu_preempted_readers(rnp)); + if (!list_empty(&rnp->blkd_tasks)) + rnp->gp_tasks = rnp->blkd_tasks.next; WARN_ON_ONCE(rnp->qsmask); } @@ -457,45 +486,49 @@ static int rcu_preempt_offline_tasks(struct rcu_state *rsp, struct rcu_node *rnp, struct rcu_data *rdp) { - int i; struct list_head *lp; struct list_head *lp_root; int retval = 0; struct rcu_node *rnp_root = rcu_get_root(rsp); - struct task_struct *tp; + struct task_struct *t; if (rnp == rnp_root) { WARN_ONCE(1, "Last CPU thought to be offlined?"); return 0; /* Shouldn't happen: at least one CPU online. */ } - WARN_ON_ONCE(rnp != rdp->mynode && - (!list_empty(&rnp->blocked_tasks[0]) || - !list_empty(&rnp->blocked_tasks[1]) || - !list_empty(&rnp->blocked_tasks[2]) || - !list_empty(&rnp->blocked_tasks[3]))); + + /* If we are on an internal node, complain bitterly. */ + WARN_ON_ONCE(rnp != rdp->mynode); /* - * Move tasks up to root rcu_node. Rely on the fact that the - * root rcu_node can be at most one ahead of the rest of the - * rcu_nodes in terms of gp_num value. This fact allows us to - * move the blocked_tasks[] array directly, element by element. + * Move tasks up to root rcu_node. Don't try to get fancy for + * this corner-case operation -- just put this node's tasks + * at the head of the root node's list, and update the root node's + * ->gp_tasks and ->exp_tasks pointers to those of this node's, + * if non-NULL. This might result in waiting for more tasks than + * absolutely necessary, but this is a good performance/complexity + * tradeoff. */ if (rcu_preempted_readers(rnp)) retval |= RCU_OFL_TASKS_NORM_GP; if (rcu_preempted_readers_exp(rnp)) retval |= RCU_OFL_TASKS_EXP_GP; - for (i = 0; i < 4; i++) { - lp = &rnp->blocked_tasks[i]; - lp_root = &rnp_root->blocked_tasks[i]; - while (!list_empty(lp)) { - tp = list_entry(lp->next, typeof(*tp), rcu_node_entry); - raw_spin_lock(&rnp_root->lock); /* irqs already disabled */ - list_del(&tp->rcu_node_entry); - tp->rcu_blocked_node = rnp_root; - list_add(&tp->rcu_node_entry, lp_root); - raw_spin_unlock(&rnp_root->lock); /* irqs remain disabled */ - } + lp = &rnp->blkd_tasks; + lp_root = &rnp_root->blkd_tasks; + while (!list_empty(lp)) { + t = list_entry(lp->next, typeof(*t), rcu_node_entry); + raw_spin_lock(&rnp_root->lock); /* irqs already disabled */ + list_del(&t->rcu_node_entry); + t->rcu_blocked_node = rnp_root; + list_add(&t->rcu_node_entry, lp_root); + if (&t->rcu_node_entry == rnp->gp_tasks) + rnp_root->gp_tasks = rnp->gp_tasks; + if (&t->rcu_node_entry == rnp->exp_tasks) + rnp_root->exp_tasks = rnp->exp_tasks; + raw_spin_unlock(&rnp_root->lock); /* irqs still disabled */ } + rnp->gp_tasks = NULL; + rnp->exp_tasks = NULL; return retval; } @@ -586,8 +619,7 @@ static DEFINE_MUTEX(sync_rcu_preempt_exp_mutex); */ static int rcu_preempted_readers_exp(struct rcu_node *rnp) { - return !list_empty(&rnp->blocked_tasks[2]) || - !list_empty(&rnp->blocked_tasks[3]); + return rnp->exp_tasks != NULL; } /* @@ -647,12 +679,13 @@ static void rcu_report_exp_rnp(struct rcu_state *rsp, struct rcu_node *rnp) static void sync_rcu_preempt_exp_init(struct rcu_state *rsp, struct rcu_node *rnp) { - int must_wait; + int must_wait = 0; raw_spin_lock(&rnp->lock); /* irqs already disabled */ - list_splice_init(&rnp->blocked_tasks[0], &rnp->blocked_tasks[2]); - list_splice_init(&rnp->blocked_tasks[1], &rnp->blocked_tasks[3]); - must_wait = rcu_preempted_readers_exp(rnp); + if (!list_empty(&rnp->blkd_tasks)) { + rnp->exp_tasks = rnp->blkd_tasks.next; + must_wait = 1; + } raw_spin_unlock(&rnp->lock); /* irqs remain disabled */ if (!must_wait) rcu_report_exp_rnp(rsp, rnp); @@ -661,9 +694,7 @@ sync_rcu_preempt_exp_init(struct rcu_state *rsp, struct rcu_node *rnp) /* * Wait for an rcu-preempt grace period, but expedite it. The basic idea * is to invoke synchronize_sched_expedited() to push all the tasks to - * the ->blocked_tasks[] lists, move all entries from the first set of - * ->blocked_tasks[] lists to the second set, and finally wait for this - * second set to drain. + * the ->blkd_tasks lists and wait for this list to drain. */ void synchronize_rcu_expedited(void) { @@ -695,7 +726,7 @@ void synchronize_rcu_expedited(void) if ((ACCESS_ONCE(sync_rcu_preempt_exp_count) - snap) > 0) goto unlock_mb_ret; /* Others did our work for us. */ - /* force all RCU readers onto blocked_tasks[]. */ + /* force all RCU readers onto ->blkd_tasks lists. */ synchronize_sched_expedited(); raw_spin_lock_irqsave(&rsp->onofflock, flags); @@ -707,7 +738,7 @@ void synchronize_rcu_expedited(void) raw_spin_unlock(&rnp->lock); /* irqs remain disabled. */ } - /* Snapshot current state of ->blocked_tasks[] lists. */ + /* Snapshot current state of ->blkd_tasks lists. */ rcu_for_each_leaf_node(rsp, rnp) sync_rcu_preempt_exp_init(rsp, rnp); if (NUM_RCU_NODES > 1) @@ -715,7 +746,7 @@ void synchronize_rcu_expedited(void) raw_spin_unlock_irqrestore(&rsp->onofflock, flags); - /* Wait for snapshotted ->blocked_tasks[] lists to drain. */ + /* Wait for snapshotted ->blkd_tasks lists to drain. */ rnp = rcu_get_root(rsp); wait_event(sync_rcu_preempt_exp_wq, sync_rcu_preempt_exp_done(rnp)); diff --git a/kernel/rcutree_trace.c b/kernel/rcutree_trace.c index 4a21ca5..1cedf94 100644 --- a/kernel/rcutree_trace.c +++ b/kernel/rcutree_trace.c @@ -161,7 +161,6 @@ static void print_one_rcu_state(struct seq_file *m, struct rcu_state *rsp) { unsigned long gpnum; int level = 0; - int phase; struct rcu_node *rnp; gpnum = rsp->gpnum; @@ -178,13 +177,11 @@ static void print_one_rcu_state(struct seq_file *m, struct rcu_state *rsp) seq_puts(m, "\n"); level = rnp->level; } - phase = gpnum & 0x1; - seq_printf(m, "%lx/%lx %c%c>%c%c %d:%d ^%d ", + seq_printf(m, "%lx/%lx %c%c>%c %d:%d ^%d ", rnp->qsmask, rnp->qsmaskinit, - "T."[list_empty(&rnp->blocked_tasks[phase])], - "E."[list_empty(&rnp->blocked_tasks[phase + 2])], - "T."[list_empty(&rnp->blocked_tasks[!phase])], - "E."[list_empty(&rnp->blocked_tasks[!phase + 2])], + ".G"[rnp->gp_tasks != NULL], + ".E"[rnp->exp_tasks != NULL], + ".T"[!list_empty(&rnp->blkd_tasks)], rnp->grplo, rnp->grphi, rnp->grpnum); } seq_puts(m, "\n"); -- cgit v1.1 From a26ac2455ffcf3be5c6ef92bc6df7182700f2114 Mon Sep 17 00:00:00 2001 From: "Paul E. McKenney" Date: Wed, 12 Jan 2011 14:10:23 -0800 Subject: rcu: move TREE_RCU from softirq to kthread If RCU priority boosting is to be meaningful, callback invocation must be boosted in addition to preempted RCU readers. Otherwise, in presence of CPU real-time threads, the grace period ends, but the callbacks don't get invoked. If the callbacks don't get invoked, the associated memory doesn't get freed, so the system is still subject to OOM. But it is not reasonable to priority-boost RCU_SOFTIRQ, so this commit moves the callback invocations to a kthread, which can be boosted easily. Also add comments and properly synchronized all accesses to rcu_cpu_kthread_task, as suggested by Lai Jiangshan. Signed-off-by: Paul E. McKenney Signed-off-by: Paul E. McKenney Reviewed-by: Josh Triplett --- kernel/rcutree.c | 340 +++++++++++++++++++++++++++++++++++++++++++++++- kernel/rcutree.h | 8 ++ kernel/rcutree_plugin.h | 4 +- kernel/softirq.c | 2 +- 4 files changed, 347 insertions(+), 7 deletions(-) (limited to 'kernel') diff --git a/kernel/rcutree.c b/kernel/rcutree.c index 0ac1cc0..18e3331 100644 --- a/kernel/rcutree.c +++ b/kernel/rcutree.c @@ -47,6 +47,8 @@ #include #include #include +#include +#include #include "rcutree.h" @@ -83,6 +85,20 @@ int rcu_scheduler_active __read_mostly; EXPORT_SYMBOL_GPL(rcu_scheduler_active); /* + * Control variables for per-CPU and per-rcu_node kthreads. These + * handle all flavors of RCU. + */ +static DEFINE_PER_CPU(struct task_struct *, rcu_cpu_kthread_task); +static DEFINE_PER_CPU(wait_queue_head_t, rcu_cpu_wq); +static DEFINE_PER_CPU(char, rcu_cpu_has_work); +static char rcu_kthreads_spawnable; + +static void rcu_node_kthread_setaffinity(struct rcu_node *rnp); +static void invoke_rcu_kthread(void); + +#define RCU_KTHREAD_PRIO 1 /* RT priority for per-CPU kthreads. */ + +/* * Return true if an RCU grace period is in progress. The ACCESS_ONCE()s * permit this function to be invoked without holding the root rcu_node * structure's ->lock, but of course results can be subject to change. @@ -1009,6 +1025,8 @@ static void rcu_send_cbs_to_online(struct rcu_state *rsp) /* * Remove the outgoing CPU from the bitmasks in the rcu_node hierarchy * and move all callbacks from the outgoing CPU to the current one. + * There can only be one CPU hotplug operation at a time, so no other + * CPU can be attempting to update rcu_cpu_kthread_task. */ static void __rcu_offline_cpu(int cpu, struct rcu_state *rsp) { @@ -1017,6 +1035,14 @@ static void __rcu_offline_cpu(int cpu, struct rcu_state *rsp) int need_report = 0; struct rcu_data *rdp = per_cpu_ptr(rsp->rda, cpu); struct rcu_node *rnp; + struct task_struct *t; + + /* Stop the CPU's kthread. */ + t = per_cpu(rcu_cpu_kthread_task, cpu); + if (t != NULL) { + per_cpu(rcu_cpu_kthread_task, cpu) = NULL; + kthread_stop(t); + } /* Exclude any attempts to start a new grace period. */ raw_spin_lock_irqsave(&rsp->onofflock, flags); @@ -1054,6 +1080,19 @@ static void __rcu_offline_cpu(int cpu, struct rcu_state *rsp) raw_spin_unlock_irqrestore(&rnp->lock, flags); if (need_report & RCU_OFL_TASKS_EXP_GP) rcu_report_exp_rnp(rsp, rnp); + + /* + * If there are no more online CPUs for this rcu_node structure, + * kill the rcu_node structure's kthread. Otherwise, adjust its + * affinity. + */ + t = rnp->node_kthread_task; + if (t != NULL && + rnp->qsmaskinit == 0) { + kthread_stop(t); + rnp->node_kthread_task = NULL; + } else + rcu_node_kthread_setaffinity(rnp); } /* @@ -1151,7 +1190,7 @@ static void rcu_do_batch(struct rcu_state *rsp, struct rcu_data *rdp) /* Re-raise the RCU softirq if there are callbacks remaining. */ if (cpu_has_callbacks_ready_to_invoke(rdp)) - raise_softirq(RCU_SOFTIRQ); + invoke_rcu_kthread(); } /* @@ -1197,7 +1236,7 @@ void rcu_check_callbacks(int cpu, int user) } rcu_preempt_check_callbacks(cpu); if (rcu_pending(cpu)) - raise_softirq(RCU_SOFTIRQ); + invoke_rcu_kthread(); } #ifdef CONFIG_SMP @@ -1361,7 +1400,7 @@ __rcu_process_callbacks(struct rcu_state *rsp, struct rcu_data *rdp) /* * Do softirq processing for the current CPU. */ -static void rcu_process_callbacks(struct softirq_action *unused) +static void rcu_process_callbacks(void) { __rcu_process_callbacks(&rcu_sched_state, &__get_cpu_var(rcu_sched_data)); @@ -1372,6 +1411,281 @@ static void rcu_process_callbacks(struct softirq_action *unused) rcu_needs_cpu_flush(); } +/* + * Wake up the current CPU's kthread. This replaces raise_softirq() + * in earlier versions of RCU. Note that because we are running on + * the current CPU with interrupts disabled, the rcu_cpu_kthread_task + * cannot disappear out from under us. + */ +static void invoke_rcu_kthread(void) +{ + unsigned long flags; + wait_queue_head_t *q; + int cpu; + + local_irq_save(flags); + cpu = smp_processor_id(); + per_cpu(rcu_cpu_has_work, cpu) = 1; + if (per_cpu(rcu_cpu_kthread_task, cpu) == NULL) { + local_irq_restore(flags); + return; + } + q = &per_cpu(rcu_cpu_wq, cpu); + wake_up(q); + local_irq_restore(flags); +} + +/* + * Timer handler to initiate the waking up of per-CPU kthreads that + * have yielded the CPU due to excess numbers of RCU callbacks. + */ +static void rcu_cpu_kthread_timer(unsigned long arg) +{ + unsigned long flags; + struct rcu_data *rdp = (struct rcu_data *)arg; + struct rcu_node *rnp = rdp->mynode; + struct task_struct *t; + + raw_spin_lock_irqsave(&rnp->lock, flags); + rnp->wakemask |= rdp->grpmask; + t = rnp->node_kthread_task; + if (t == NULL) { + raw_spin_unlock_irqrestore(&rnp->lock, flags); + return; + } + wake_up_process(t); + raw_spin_unlock_irqrestore(&rnp->lock, flags); +} + +/* + * Drop to non-real-time priority and yield, but only after posting a + * timer that will cause us to regain our real-time priority if we + * remain preempted. Either way, we restore our real-time priority + * before returning. + */ +static void rcu_yield(int cpu) +{ + struct rcu_data *rdp = per_cpu_ptr(rcu_sched_state.rda, cpu); + struct sched_param sp; + struct timer_list yield_timer; + + setup_timer_on_stack(&yield_timer, rcu_cpu_kthread_timer, (unsigned long)rdp); + mod_timer(&yield_timer, jiffies + 2); + sp.sched_priority = 0; + sched_setscheduler_nocheck(current, SCHED_NORMAL, &sp); + schedule(); + sp.sched_priority = RCU_KTHREAD_PRIO; + sched_setscheduler_nocheck(current, SCHED_FIFO, &sp); + del_timer(&yield_timer); +} + +/* + * Handle cases where the rcu_cpu_kthread() ends up on the wrong CPU. + * This can happen while the corresponding CPU is either coming online + * or going offline. We cannot wait until the CPU is fully online + * before starting the kthread, because the various notifier functions + * can wait for RCU grace periods. So we park rcu_cpu_kthread() until + * the corresponding CPU is online. + * + * Return 1 if the kthread needs to stop, 0 otherwise. + * + * Caller must disable bh. This function can momentarily enable it. + */ +static int rcu_cpu_kthread_should_stop(int cpu) +{ + while (cpu_is_offline(cpu) || + !cpumask_equal(¤t->cpus_allowed, cpumask_of(cpu)) || + smp_processor_id() != cpu) { + if (kthread_should_stop()) + return 1; + local_bh_enable(); + schedule_timeout_uninterruptible(1); + if (!cpumask_equal(¤t->cpus_allowed, cpumask_of(cpu))) + set_cpus_allowed_ptr(current, cpumask_of(cpu)); + local_bh_disable(); + } + return 0; +} + +/* + * Per-CPU kernel thread that invokes RCU callbacks. This replaces the + * earlier RCU softirq. + */ +static int rcu_cpu_kthread(void *arg) +{ + int cpu = (int)(long)arg; + unsigned long flags; + int spincnt = 0; + wait_queue_head_t *wqp = &per_cpu(rcu_cpu_wq, cpu); + char work; + char *workp = &per_cpu(rcu_cpu_has_work, cpu); + + for (;;) { + wait_event_interruptible(*wqp, + *workp != 0 || kthread_should_stop()); + local_bh_disable(); + if (rcu_cpu_kthread_should_stop(cpu)) { + local_bh_enable(); + break; + } + local_irq_save(flags); + work = *workp; + *workp = 0; + local_irq_restore(flags); + if (work) + rcu_process_callbacks(); + local_bh_enable(); + if (*workp != 0) + spincnt++; + else + spincnt = 0; + if (spincnt > 10) { + rcu_yield(cpu); + spincnt = 0; + } + } + return 0; +} + +/* + * Spawn a per-CPU kthread, setting up affinity and priority. + * Because the CPU hotplug lock is held, no other CPU will be attempting + * to manipulate rcu_cpu_kthread_task. There might be another CPU + * attempting to access it during boot, but the locking in kthread_bind() + * will enforce sufficient ordering. + */ +static int __cpuinit rcu_spawn_one_cpu_kthread(int cpu) +{ + struct sched_param sp; + struct task_struct *t; + + if (!rcu_kthreads_spawnable || + per_cpu(rcu_cpu_kthread_task, cpu) != NULL) + return 0; + t = kthread_create(rcu_cpu_kthread, (void *)(long)cpu, "rcuc%d", cpu); + if (IS_ERR(t)) + return PTR_ERR(t); + kthread_bind(t, cpu); + WARN_ON_ONCE(per_cpu(rcu_cpu_kthread_task, cpu) != NULL); + per_cpu(rcu_cpu_kthread_task, cpu) = t; + wake_up_process(t); + sp.sched_priority = RCU_KTHREAD_PRIO; + sched_setscheduler_nocheck(t, SCHED_FIFO, &sp); + return 0; +} + +/* + * Per-rcu_node kthread, which is in charge of waking up the per-CPU + * kthreads when needed. We ignore requests to wake up kthreads + * for offline CPUs, which is OK because force_quiescent_state() + * takes care of this case. + */ +static int rcu_node_kthread(void *arg) +{ + int cpu; + unsigned long flags; + unsigned long mask; + struct rcu_node *rnp = (struct rcu_node *)arg; + struct sched_param sp; + struct task_struct *t; + + for (;;) { + wait_event_interruptible(rnp->node_wq, rnp->wakemask != 0 || + kthread_should_stop()); + if (kthread_should_stop()) + break; + raw_spin_lock_irqsave(&rnp->lock, flags); + mask = rnp->wakemask; + rnp->wakemask = 0; + raw_spin_unlock_irqrestore(&rnp->lock, flags); + for (cpu = rnp->grplo; cpu <= rnp->grphi; cpu++, mask >>= 1) { + if ((mask & 0x1) == 0) + continue; + preempt_disable(); + t = per_cpu(rcu_cpu_kthread_task, cpu); + if (!cpu_online(cpu) || t == NULL) { + preempt_enable(); + continue; + } + per_cpu(rcu_cpu_has_work, cpu) = 1; + sp.sched_priority = RCU_KTHREAD_PRIO; + sched_setscheduler_nocheck(t, SCHED_FIFO, &sp); + preempt_enable(); + } + } + return 0; +} + +/* + * Set the per-rcu_node kthread's affinity to cover all CPUs that are + * served by the rcu_node in question. + */ +static void rcu_node_kthread_setaffinity(struct rcu_node *rnp) +{ + cpumask_var_t cm; + int cpu; + unsigned long mask = rnp->qsmaskinit; + + if (rnp->node_kthread_task == NULL || + rnp->qsmaskinit == 0) + return; + if (!alloc_cpumask_var(&cm, GFP_KERNEL)) + return; + cpumask_clear(cm); + for (cpu = rnp->grplo; cpu <= rnp->grphi; cpu++, mask >>= 1) + if (mask & 0x1) + cpumask_set_cpu(cpu, cm); + set_cpus_allowed_ptr(rnp->node_kthread_task, cm); + free_cpumask_var(cm); +} + +/* + * Spawn a per-rcu_node kthread, setting priority and affinity. + */ +static int __cpuinit rcu_spawn_one_node_kthread(struct rcu_state *rsp, + struct rcu_node *rnp) +{ + int rnp_index = rnp - &rsp->node[0]; + struct sched_param sp; + struct task_struct *t; + + if (!rcu_kthreads_spawnable || + rnp->qsmaskinit == 0 || + rnp->node_kthread_task != NULL) + return 0; + t = kthread_create(rcu_node_kthread, (void *)rnp, "rcun%d", rnp_index); + if (IS_ERR(t)) + return PTR_ERR(t); + rnp->node_kthread_task = t; + wake_up_process(t); + sp.sched_priority = 99; + sched_setscheduler_nocheck(t, SCHED_FIFO, &sp); + return 0; +} + +/* + * Spawn all kthreads -- called as soon as the scheduler is running. + */ +static int __init rcu_spawn_kthreads(void) +{ + int cpu; + struct rcu_node *rnp; + + rcu_kthreads_spawnable = 1; + for_each_possible_cpu(cpu) { + init_waitqueue_head(&per_cpu(rcu_cpu_wq, cpu)); + per_cpu(rcu_cpu_has_work, cpu) = 0; + if (cpu_online(cpu)) + (void)rcu_spawn_one_cpu_kthread(cpu); + } + rcu_for_each_leaf_node(&rcu_sched_state, rnp) { + init_waitqueue_head(&rnp->node_wq); + (void)rcu_spawn_one_node_kthread(&rcu_sched_state, rnp); + } + return 0; +} +early_initcall(rcu_spawn_kthreads); + static void __call_rcu(struct rcu_head *head, void (*func)(struct rcu_head *rcu), struct rcu_state *rsp) @@ -1771,6 +2085,19 @@ static void __cpuinit rcu_online_cpu(int cpu) rcu_preempt_init_percpu_data(cpu); } +static void __cpuinit rcu_online_kthreads(int cpu) +{ + struct rcu_data *rdp = per_cpu_ptr(rcu_sched_state.rda, cpu); + struct rcu_node *rnp = rdp->mynode; + + /* Fire up the incoming CPU's kthread and leaf rcu_node kthread. */ + if (rcu_kthreads_spawnable) { + (void)rcu_spawn_one_cpu_kthread(cpu); + if (rnp->node_kthread_task == NULL) + (void)rcu_spawn_one_node_kthread(&rcu_sched_state, rnp); + } +} + /* * Handle CPU online/offline notification events. */ @@ -1778,11 +2105,17 @@ static int __cpuinit rcu_cpu_notify(struct notifier_block *self, unsigned long action, void *hcpu) { long cpu = (long)hcpu; + struct rcu_data *rdp = per_cpu_ptr(rcu_sched_state.rda, cpu); + struct rcu_node *rnp = rdp->mynode; switch (action) { case CPU_UP_PREPARE: case CPU_UP_PREPARE_FROZEN: rcu_online_cpu(cpu); + rcu_online_kthreads(cpu); + break; + case CPU_ONLINE: + rcu_node_kthread_setaffinity(rnp); break; case CPU_DYING: case CPU_DYING_FROZEN: @@ -1923,7 +2256,6 @@ void __init rcu_init(void) rcu_init_one(&rcu_sched_state, &rcu_sched_data); rcu_init_one(&rcu_bh_state, &rcu_bh_data); __rcu_init_preempt(); - open_softirq(RCU_SOFTIRQ, rcu_process_callbacks); /* * We don't need protection against CPU-hotplug here because diff --git a/kernel/rcutree.h b/kernel/rcutree.h index 5a439c1..c021380 100644 --- a/kernel/rcutree.h +++ b/kernel/rcutree.h @@ -111,6 +111,7 @@ struct rcu_node { /* elements that need to drain to allow the */ /* current expedited grace period to */ /* complete (only for TREE_PREEMPT_RCU). */ + unsigned long wakemask; /* CPUs whose kthread needs to be awakened. */ unsigned long qsmaskinit; /* Per-GP initial value for qsmask & expmask. */ unsigned long grpmask; /* Mask to apply to parent qsmask. */ @@ -134,6 +135,13 @@ struct rcu_node { /* if there is no such task. If there */ /* is no current expedited grace period, */ /* then there can cannot be any such task. */ + struct task_struct *node_kthread_task; + /* kthread that takes care of this rcu_node */ + /* structure, for example, awakening the */ + /* per-CPU kthreads as needed. */ + wait_queue_head_t node_wq; + /* Wait queue on which to park the per-node */ + /* kthread. */ } ____cacheline_internodealigned_in_smp; /* diff --git a/kernel/rcutree_plugin.h b/kernel/rcutree_plugin.h index 774f010..b9bd69a 100644 --- a/kernel/rcutree_plugin.h +++ b/kernel/rcutree_plugin.h @@ -1206,7 +1206,7 @@ static DEFINE_PER_CPU(unsigned long, rcu_dyntick_holdoff); * * Because it is not legal to invoke rcu_process_callbacks() with irqs * disabled, we do one pass of force_quiescent_state(), then do a - * raise_softirq() to cause rcu_process_callbacks() to be invoked later. + * invoke_rcu_kthread() to cause rcu_process_callbacks() to be invoked later. * The per-cpu rcu_dyntick_drain variable controls the sequencing. */ int rcu_needs_cpu(int cpu) @@ -1257,7 +1257,7 @@ int rcu_needs_cpu(int cpu) /* If RCU callbacks are still pending, RCU still needs this CPU. */ if (c) - raise_softirq(RCU_SOFTIRQ); + invoke_rcu_kthread(); return c; } diff --git a/kernel/softirq.c b/kernel/softirq.c index 174f976..1396017 100644 --- a/kernel/softirq.c +++ b/kernel/softirq.c @@ -58,7 +58,7 @@ DEFINE_PER_CPU(struct task_struct *, ksoftirqd); char *softirq_to_name[NR_SOFTIRQS] = { "HI", "TIMER", "NET_TX", "NET_RX", "BLOCK", "BLOCK_IOPOLL", - "TASKLET", "SCHED", "HRTIMER", "RCU" + "TASKLET", "SCHED", "HRTIMER" }; /* -- cgit v1.1 From 27f4d28057adf98750cf863c40baefb12f5b6d21 Mon Sep 17 00:00:00 2001 From: "Paul E. McKenney" Date: Mon, 7 Feb 2011 12:47:15 -0800 Subject: rcu: priority boosting for TREE_PREEMPT_RCU Add priority boosting for TREE_PREEMPT_RCU, similar to that for TINY_PREEMPT_RCU. This is enabled by the default-off RCU_BOOST kernel parameter. The priority to which to boost preempted RCU readers is controlled by the RCU_BOOST_PRIO kernel parameter (defaulting to real-time priority 1) and the time to wait before boosting the readers who are blocking a given grace period is controlled by the RCU_BOOST_DELAY kernel parameter (defaulting to 500 milliseconds). Signed-off-by: Paul E. McKenney Signed-off-by: Paul E. McKenney Reviewed-by: Josh Triplett --- kernel/rcutree.c | 115 ++++++++++++------ kernel/rcutree.h | 31 ++++- kernel/rcutree_plugin.h | 314 ++++++++++++++++++++++++++++++++++++++++++++++-- 3 files changed, 410 insertions(+), 50 deletions(-) (limited to 'kernel') diff --git a/kernel/rcutree.c b/kernel/rcutree.c index 18e3331..28fd92a 100644 --- a/kernel/rcutree.c +++ b/kernel/rcutree.c @@ -81,6 +81,8 @@ DEFINE_PER_CPU(struct rcu_data, rcu_sched_data); struct rcu_state rcu_bh_state = RCU_STATE_INITIALIZER(rcu_bh_state); DEFINE_PER_CPU(struct rcu_data, rcu_bh_data); +static struct rcu_state *rcu_state; + int rcu_scheduler_active __read_mostly; EXPORT_SYMBOL_GPL(rcu_scheduler_active); @@ -94,7 +96,7 @@ static DEFINE_PER_CPU(char, rcu_cpu_has_work); static char rcu_kthreads_spawnable; static void rcu_node_kthread_setaffinity(struct rcu_node *rnp); -static void invoke_rcu_kthread(void); +static void invoke_rcu_cpu_kthread(void); #define RCU_KTHREAD_PRIO 1 /* RT priority for per-CPU kthreads. */ @@ -791,6 +793,7 @@ rcu_start_gp(struct rcu_state *rsp, unsigned long flags) rnp->completed = rsp->completed; rsp->signaled = RCU_SIGNAL_INIT; /* force_quiescent_state OK. */ rcu_start_gp_per_cpu(rsp, rnp, rdp); + rcu_preempt_boost_start_gp(rnp); raw_spin_unlock_irqrestore(&rnp->lock, flags); return; } @@ -826,6 +829,7 @@ rcu_start_gp(struct rcu_state *rsp, unsigned long flags) rnp->completed = rsp->completed; if (rnp == rdp->mynode) rcu_start_gp_per_cpu(rsp, rnp, rdp); + rcu_preempt_boost_start_gp(rnp); raw_spin_unlock(&rnp->lock); /* irqs remain disabled. */ } @@ -882,7 +886,7 @@ rcu_report_qs_rnp(unsigned long mask, struct rcu_state *rsp, return; } rnp->qsmask &= ~mask; - if (rnp->qsmask != 0 || rcu_preempted_readers(rnp)) { + if (rnp->qsmask != 0 || rcu_preempt_blocked_readers_cgp(rnp)) { /* Other bits still set at this level, so done. */ raw_spin_unlock_irqrestore(&rnp->lock, flags); @@ -1089,8 +1093,11 @@ static void __rcu_offline_cpu(int cpu, struct rcu_state *rsp) t = rnp->node_kthread_task; if (t != NULL && rnp->qsmaskinit == 0) { - kthread_stop(t); + raw_spin_lock_irqsave(&rnp->lock, flags); rnp->node_kthread_task = NULL; + raw_spin_unlock_irqrestore(&rnp->lock, flags); + kthread_stop(t); + rcu_stop_boost_kthread(rnp); } else rcu_node_kthread_setaffinity(rnp); } @@ -1190,7 +1197,7 @@ static void rcu_do_batch(struct rcu_state *rsp, struct rcu_data *rdp) /* Re-raise the RCU softirq if there are callbacks remaining. */ if (cpu_has_callbacks_ready_to_invoke(rdp)) - invoke_rcu_kthread(); + invoke_rcu_cpu_kthread(); } /* @@ -1236,7 +1243,7 @@ void rcu_check_callbacks(int cpu, int user) } rcu_preempt_check_callbacks(cpu); if (rcu_pending(cpu)) - invoke_rcu_kthread(); + invoke_rcu_cpu_kthread(); } #ifdef CONFIG_SMP @@ -1244,6 +1251,8 @@ void rcu_check_callbacks(int cpu, int user) /* * Scan the leaf rcu_node structures, processing dyntick state for any that * have not yet encountered a quiescent state, using the function specified. + * Also initiate boosting for any threads blocked on the root rcu_node. + * * The caller must have suppressed start of new grace periods. */ static void force_qs_rnp(struct rcu_state *rsp, int (*f)(struct rcu_data *)) @@ -1262,6 +1271,7 @@ static void force_qs_rnp(struct rcu_state *rsp, int (*f)(struct rcu_data *)) return; } if (rnp->qsmask == 0) { + rcu_initiate_boost(rnp); raw_spin_unlock_irqrestore(&rnp->lock, flags); continue; } @@ -1280,6 +1290,11 @@ static void force_qs_rnp(struct rcu_state *rsp, int (*f)(struct rcu_data *)) } raw_spin_unlock_irqrestore(&rnp->lock, flags); } + rnp = rcu_get_root(rsp); + raw_spin_lock_irqsave(&rnp->lock, flags); + if (rnp->qsmask == 0) + rcu_initiate_boost(rnp); + raw_spin_unlock_irqrestore(&rnp->lock, flags); } /* @@ -1417,7 +1432,7 @@ static void rcu_process_callbacks(void) * the current CPU with interrupts disabled, the rcu_cpu_kthread_task * cannot disappear out from under us. */ -static void invoke_rcu_kthread(void) +static void invoke_rcu_cpu_kthread(void) { unsigned long flags; wait_queue_head_t *q; @@ -1436,24 +1451,33 @@ static void invoke_rcu_kthread(void) } /* + * Wake up the specified per-rcu_node-structure kthread. + * The caller must hold ->lock. + */ +static void invoke_rcu_node_kthread(struct rcu_node *rnp) +{ + struct task_struct *t; + + t = rnp->node_kthread_task; + if (t != NULL) + wake_up_process(t); +} + +/* * Timer handler to initiate the waking up of per-CPU kthreads that * have yielded the CPU due to excess numbers of RCU callbacks. + * We wake up the per-rcu_node kthread, which in turn will wake up + * the booster kthread. */ static void rcu_cpu_kthread_timer(unsigned long arg) { unsigned long flags; - struct rcu_data *rdp = (struct rcu_data *)arg; + struct rcu_data *rdp = per_cpu_ptr(rcu_state->rda, arg); struct rcu_node *rnp = rdp->mynode; - struct task_struct *t; raw_spin_lock_irqsave(&rnp->lock, flags); rnp->wakemask |= rdp->grpmask; - t = rnp->node_kthread_task; - if (t == NULL) { - raw_spin_unlock_irqrestore(&rnp->lock, flags); - return; - } - wake_up_process(t); + invoke_rcu_node_kthread(rnp); raw_spin_unlock_irqrestore(&rnp->lock, flags); } @@ -1463,13 +1487,12 @@ static void rcu_cpu_kthread_timer(unsigned long arg) * remain preempted. Either way, we restore our real-time priority * before returning. */ -static void rcu_yield(int cpu) +static void rcu_yield(void (*f)(unsigned long), unsigned long arg) { - struct rcu_data *rdp = per_cpu_ptr(rcu_sched_state.rda, cpu); struct sched_param sp; struct timer_list yield_timer; - setup_timer_on_stack(&yield_timer, rcu_cpu_kthread_timer, (unsigned long)rdp); + setup_timer_on_stack(&yield_timer, f, arg); mod_timer(&yield_timer, jiffies + 2); sp.sched_priority = 0; sched_setscheduler_nocheck(current, SCHED_NORMAL, &sp); @@ -1540,7 +1563,7 @@ static int rcu_cpu_kthread(void *arg) else spincnt = 0; if (spincnt > 10) { - rcu_yield(cpu); + rcu_yield(rcu_cpu_kthread_timer, (unsigned long)cpu); spincnt = 0; } } @@ -1597,6 +1620,7 @@ static int rcu_node_kthread(void *arg) raw_spin_lock_irqsave(&rnp->lock, flags); mask = rnp->wakemask; rnp->wakemask = 0; + rcu_initiate_boost(rnp); raw_spin_unlock_irqrestore(&rnp->lock, flags); for (cpu = rnp->grplo; cpu <= rnp->grphi; cpu++, mask >>= 1) { if ((mask & 0x1) == 0) @@ -1618,7 +1642,8 @@ static int rcu_node_kthread(void *arg) /* * Set the per-rcu_node kthread's affinity to cover all CPUs that are - * served by the rcu_node in question. + * served by the rcu_node in question. The CPU hotplug lock is still + * held, so the value of rnp->qsmaskinit will be stable. */ static void rcu_node_kthread_setaffinity(struct rcu_node *rnp) { @@ -1626,8 +1651,7 @@ static void rcu_node_kthread_setaffinity(struct rcu_node *rnp) int cpu; unsigned long mask = rnp->qsmaskinit; - if (rnp->node_kthread_task == NULL || - rnp->qsmaskinit == 0) + if (rnp->node_kthread_task == NULL || mask == 0) return; if (!alloc_cpumask_var(&cm, GFP_KERNEL)) return; @@ -1636,31 +1660,40 @@ static void rcu_node_kthread_setaffinity(struct rcu_node *rnp) if (mask & 0x1) cpumask_set_cpu(cpu, cm); set_cpus_allowed_ptr(rnp->node_kthread_task, cm); + rcu_boost_kthread_setaffinity(rnp, cm); free_cpumask_var(cm); } /* * Spawn a per-rcu_node kthread, setting priority and affinity. + * Called during boot before online/offline can happen, or, if + * during runtime, with the main CPU-hotplug locks held. So only + * one of these can be executing at a time. */ static int __cpuinit rcu_spawn_one_node_kthread(struct rcu_state *rsp, struct rcu_node *rnp) { + unsigned long flags; int rnp_index = rnp - &rsp->node[0]; struct sched_param sp; struct task_struct *t; if (!rcu_kthreads_spawnable || - rnp->qsmaskinit == 0 || - rnp->node_kthread_task != NULL) + rnp->qsmaskinit == 0) return 0; - t = kthread_create(rcu_node_kthread, (void *)rnp, "rcun%d", rnp_index); - if (IS_ERR(t)) - return PTR_ERR(t); - rnp->node_kthread_task = t; - wake_up_process(t); - sp.sched_priority = 99; - sched_setscheduler_nocheck(t, SCHED_FIFO, &sp); - return 0; + if (rnp->node_kthread_task == NULL) { + t = kthread_create(rcu_node_kthread, (void *)rnp, + "rcun%d", rnp_index); + if (IS_ERR(t)) + return PTR_ERR(t); + raw_spin_lock_irqsave(&rnp->lock, flags); + rnp->node_kthread_task = t; + raw_spin_unlock_irqrestore(&rnp->lock, flags); + wake_up_process(t); + sp.sched_priority = 99; + sched_setscheduler_nocheck(t, SCHED_FIFO, &sp); + } + return rcu_spawn_one_boost_kthread(rsp, rnp, rnp_index); } /* @@ -1678,10 +1711,16 @@ static int __init rcu_spawn_kthreads(void) if (cpu_online(cpu)) (void)rcu_spawn_one_cpu_kthread(cpu); } - rcu_for_each_leaf_node(&rcu_sched_state, rnp) { - init_waitqueue_head(&rnp->node_wq); - (void)rcu_spawn_one_node_kthread(&rcu_sched_state, rnp); - } + rnp = rcu_get_root(rcu_state); + init_waitqueue_head(&rnp->node_wq); + rcu_init_boost_waitqueue(rnp); + (void)rcu_spawn_one_node_kthread(rcu_state, rnp); + if (NUM_RCU_NODES > 1) + rcu_for_each_leaf_node(rcu_state, rnp) { + init_waitqueue_head(&rnp->node_wq); + rcu_init_boost_waitqueue(rnp); + (void)rcu_spawn_one_node_kthread(rcu_state, rnp); + } return 0; } early_initcall(rcu_spawn_kthreads); @@ -2087,14 +2126,14 @@ static void __cpuinit rcu_online_cpu(int cpu) static void __cpuinit rcu_online_kthreads(int cpu) { - struct rcu_data *rdp = per_cpu_ptr(rcu_sched_state.rda, cpu); + struct rcu_data *rdp = per_cpu_ptr(rcu_state->rda, cpu); struct rcu_node *rnp = rdp->mynode; /* Fire up the incoming CPU's kthread and leaf rcu_node kthread. */ if (rcu_kthreads_spawnable) { (void)rcu_spawn_one_cpu_kthread(cpu); if (rnp->node_kthread_task == NULL) - (void)rcu_spawn_one_node_kthread(&rcu_sched_state, rnp); + (void)rcu_spawn_one_node_kthread(rcu_state, rnp); } } @@ -2105,7 +2144,7 @@ static int __cpuinit rcu_cpu_notify(struct notifier_block *self, unsigned long action, void *hcpu) { long cpu = (long)hcpu; - struct rcu_data *rdp = per_cpu_ptr(rcu_sched_state.rda, cpu); + struct rcu_data *rdp = per_cpu_ptr(rcu_state->rda, cpu); struct rcu_node *rnp = rdp->mynode; switch (action) { diff --git a/kernel/rcutree.h b/kernel/rcutree.h index c021380..8db0cdc 100644 --- a/kernel/rcutree.h +++ b/kernel/rcutree.h @@ -135,6 +135,24 @@ struct rcu_node { /* if there is no such task. If there */ /* is no current expedited grace period, */ /* then there can cannot be any such task. */ +#ifdef CONFIG_RCU_BOOST + struct list_head *boost_tasks; + /* Pointer to first task that needs to be */ + /* priority boosted, or NULL if no priority */ + /* boosting is needed for this rcu_node */ + /* structure. If there are no tasks */ + /* queued on this rcu_node structure that */ + /* are blocking the current grace period, */ + /* there can be no such task. */ + unsigned long boost_time; + /* When to start boosting (jiffies). */ + struct task_struct *boost_kthread_task; + /* kthread that takes care of priority */ + /* boosting for this rcu_node structure. */ + wait_queue_head_t boost_wq; + /* Wait queue on which to park the boost */ + /* kthread. */ +#endif /* #ifdef CONFIG_RCU_BOOST */ struct task_struct *node_kthread_task; /* kthread that takes care of this rcu_node */ /* structure, for example, awakening the */ @@ -365,7 +383,7 @@ DECLARE_PER_CPU(struct rcu_data, rcu_preempt_data); static void rcu_bootup_announce(void); long rcu_batches_completed(void); static void rcu_preempt_note_context_switch(int cpu); -static int rcu_preempted_readers(struct rcu_node *rnp); +static int rcu_preempt_blocked_readers_cgp(struct rcu_node *rnp); #ifdef CONFIG_HOTPLUG_CPU static void rcu_report_unblock_qs_rnp(struct rcu_node *rnp, unsigned long flags); @@ -392,5 +410,16 @@ static void __cpuinit rcu_preempt_init_percpu_data(int cpu); static void rcu_preempt_send_cbs_to_online(void); static void __init __rcu_init_preempt(void); static void rcu_needs_cpu_flush(void); +static void __init rcu_init_boost_waitqueue(struct rcu_node *rnp); +static void rcu_initiate_boost(struct rcu_node *rnp); +static void rcu_boost_kthread_setaffinity(struct rcu_node *rnp, + cpumask_var_t cm); +static void rcu_preempt_boost_start_gp(struct rcu_node *rnp); +static int __cpuinit rcu_spawn_one_boost_kthread(struct rcu_state *rsp, + struct rcu_node *rnp, + int rnp_index); +#ifdef CONFIG_HOTPLUG_CPU +static void rcu_stop_boost_kthread(struct rcu_node *rnp); +#endif /* #ifdef CONFIG_HOTPLUG_CPU */ #endif /* #ifndef RCU_TREE_NONCORE */ diff --git a/kernel/rcutree_plugin.h b/kernel/rcutree_plugin.h index b9bd69a..5964f82 100644 --- a/kernel/rcutree_plugin.h +++ b/kernel/rcutree_plugin.h @@ -66,6 +66,7 @@ static void __init rcu_bootup_announce_oddness(void) struct rcu_state rcu_preempt_state = RCU_STATE_INITIALIZER(rcu_preempt_state); DEFINE_PER_CPU(struct rcu_data, rcu_preempt_data); +static struct rcu_state *rcu_state = &rcu_preempt_state; static int rcu_preempted_readers_exp(struct rcu_node *rnp); @@ -179,6 +180,10 @@ static void rcu_preempt_note_context_switch(int cpu) if ((rnp->qsmask & rdp->grpmask) && rnp->gp_tasks != NULL) { list_add(&t->rcu_node_entry, rnp->gp_tasks->prev); rnp->gp_tasks = &t->rcu_node_entry; +#ifdef CONFIG_RCU_BOOST + if (rnp->boost_tasks != NULL) + rnp->boost_tasks = rnp->gp_tasks; +#endif /* #ifdef CONFIG_RCU_BOOST */ } else { list_add(&t->rcu_node_entry, &rnp->blkd_tasks); if (rnp->qsmask & rdp->grpmask) @@ -218,7 +223,7 @@ EXPORT_SYMBOL_GPL(__rcu_read_lock); * for the specified rcu_node structure. If the caller needs a reliable * answer, it must hold the rcu_node's ->lock. */ -static int rcu_preempted_readers(struct rcu_node *rnp) +static int rcu_preempt_blocked_readers_cgp(struct rcu_node *rnp) { return rnp->gp_tasks != NULL; } @@ -236,7 +241,7 @@ static void rcu_report_unblock_qs_rnp(struct rcu_node *rnp, unsigned long flags) unsigned long mask; struct rcu_node *rnp_p; - if (rnp->qsmask != 0 || rcu_preempted_readers(rnp)) { + if (rnp->qsmask != 0 || rcu_preempt_blocked_readers_cgp(rnp)) { raw_spin_unlock_irqrestore(&rnp->lock, flags); return; /* Still need more quiescent states! */ } @@ -325,7 +330,7 @@ static void rcu_read_unlock_special(struct task_struct *t) break; raw_spin_unlock(&rnp->lock); /* irqs remain disabled. */ } - empty = !rcu_preempted_readers(rnp); + empty = !rcu_preempt_blocked_readers_cgp(rnp); empty_exp = !rcu_preempted_readers_exp(rnp); smp_mb(); /* ensure expedited fastpath sees end of RCU c-s. */ np = rcu_next_node_entry(t, rnp); @@ -334,6 +339,10 @@ static void rcu_read_unlock_special(struct task_struct *t) rnp->gp_tasks = np; if (&t->rcu_node_entry == rnp->exp_tasks) rnp->exp_tasks = np; +#ifdef CONFIG_RCU_BOOST + if (&t->rcu_node_entry == rnp->boost_tasks) + rnp->boost_tasks = np; +#endif /* #ifdef CONFIG_RCU_BOOST */ t->rcu_blocked_node = NULL; /* @@ -346,6 +355,15 @@ static void rcu_read_unlock_special(struct task_struct *t) else rcu_report_unblock_qs_rnp(rnp, flags); +#ifdef CONFIG_RCU_BOOST + /* Unboost if we were boosted. */ + if (special & RCU_READ_UNLOCK_BOOSTED) { + t->rcu_read_unlock_special &= ~RCU_READ_UNLOCK_BOOSTED; + rt_mutex_unlock(t->rcu_boost_mutex); + t->rcu_boost_mutex = NULL; + } +#endif /* #ifdef CONFIG_RCU_BOOST */ + /* * If this was the last task on the expedited lists, * then we need to report up the rcu_node hierarchy. @@ -391,7 +409,7 @@ static void rcu_print_detail_task_stall_rnp(struct rcu_node *rnp) unsigned long flags; struct task_struct *t; - if (!rcu_preempted_readers(rnp)) + if (!rcu_preempt_blocked_readers_cgp(rnp)) return; raw_spin_lock_irqsave(&rnp->lock, flags); t = list_entry(rnp->gp_tasks, @@ -430,7 +448,7 @@ static void rcu_print_task_stall(struct rcu_node *rnp) { struct task_struct *t; - if (!rcu_preempted_readers(rnp)) + if (!rcu_preempt_blocked_readers_cgp(rnp)) return; t = list_entry(rnp->gp_tasks, struct task_struct, rcu_node_entry); @@ -460,7 +478,7 @@ static void rcu_preempt_stall_reset(void) */ static void rcu_preempt_check_blocked_tasks(struct rcu_node *rnp) { - WARN_ON_ONCE(rcu_preempted_readers(rnp)); + WARN_ON_ONCE(rcu_preempt_blocked_readers_cgp(rnp)); if (!list_empty(&rnp->blkd_tasks)) rnp->gp_tasks = rnp->blkd_tasks.next; WARN_ON_ONCE(rnp->qsmask); @@ -509,7 +527,7 @@ static int rcu_preempt_offline_tasks(struct rcu_state *rsp, * absolutely necessary, but this is a good performance/complexity * tradeoff. */ - if (rcu_preempted_readers(rnp)) + if (rcu_preempt_blocked_readers_cgp(rnp)) retval |= RCU_OFL_TASKS_NORM_GP; if (rcu_preempted_readers_exp(rnp)) retval |= RCU_OFL_TASKS_EXP_GP; @@ -525,8 +543,22 @@ static int rcu_preempt_offline_tasks(struct rcu_state *rsp, rnp_root->gp_tasks = rnp->gp_tasks; if (&t->rcu_node_entry == rnp->exp_tasks) rnp_root->exp_tasks = rnp->exp_tasks; +#ifdef CONFIG_RCU_BOOST + if (&t->rcu_node_entry == rnp->boost_tasks) + rnp_root->boost_tasks = rnp->boost_tasks; +#endif /* #ifdef CONFIG_RCU_BOOST */ raw_spin_unlock(&rnp_root->lock); /* irqs still disabled */ } + +#ifdef CONFIG_RCU_BOOST + /* In case root is being boosted and leaf is not. */ + raw_spin_lock(&rnp_root->lock); /* irqs already disabled */ + if (rnp_root->boost_tasks != NULL && + rnp_root->boost_tasks != rnp_root->gp_tasks) + rnp_root->boost_tasks = rnp_root->gp_tasks; + raw_spin_unlock(&rnp_root->lock); /* irqs still disabled */ +#endif /* #ifdef CONFIG_RCU_BOOST */ + rnp->gp_tasks = NULL; rnp->exp_tasks = NULL; return retval; @@ -684,6 +716,7 @@ sync_rcu_preempt_exp_init(struct rcu_state *rsp, struct rcu_node *rnp) raw_spin_lock(&rnp->lock); /* irqs already disabled */ if (!list_empty(&rnp->blkd_tasks)) { rnp->exp_tasks = rnp->blkd_tasks.next; + rcu_initiate_boost(rnp); must_wait = 1; } raw_spin_unlock(&rnp->lock); /* irqs remain disabled */ @@ -830,6 +863,8 @@ void exit_rcu(void) #else /* #ifdef CONFIG_TREE_PREEMPT_RCU */ +static struct rcu_state *rcu_state = &rcu_sched_state; + /* * Tell them what RCU they are running. */ @@ -870,7 +905,7 @@ static void rcu_preempt_note_context_switch(int cpu) * Because preemptable RCU does not exist, there are never any preempted * RCU readers. */ -static int rcu_preempted_readers(struct rcu_node *rnp) +static int rcu_preempt_blocked_readers_cgp(struct rcu_node *rnp) { return 0; } @@ -1034,6 +1069,263 @@ static void __init __rcu_init_preempt(void) #endif /* #else #ifdef CONFIG_TREE_PREEMPT_RCU */ +#ifdef CONFIG_RCU_BOOST + +#include "rtmutex_common.h" + +/* + * Carry out RCU priority boosting on the task indicated by ->exp_tasks + * or ->boost_tasks, advancing the pointer to the next task in the + * ->blkd_tasks list. + * + * Note that irqs must be enabled: boosting the task can block. + * Returns 1 if there are more tasks needing to be boosted. + */ +static int rcu_boost(struct rcu_node *rnp) +{ + unsigned long flags; + struct rt_mutex mtx; + struct task_struct *t; + struct list_head *tb; + + if (rnp->exp_tasks == NULL && rnp->boost_tasks == NULL) + return 0; /* Nothing left to boost. */ + + raw_spin_lock_irqsave(&rnp->lock, flags); + + /* + * Recheck under the lock: all tasks in need of boosting + * might exit their RCU read-side critical sections on their own. + */ + if (rnp->exp_tasks == NULL && rnp->boost_tasks == NULL) { + raw_spin_unlock_irqrestore(&rnp->lock, flags); + return 0; + } + + /* + * Preferentially boost tasks blocking expedited grace periods. + * This cannot starve the normal grace periods because a second + * expedited grace period must boost all blocked tasks, including + * those blocking the pre-existing normal grace period. + */ + if (rnp->exp_tasks != NULL) + tb = rnp->exp_tasks; + else + tb = rnp->boost_tasks; + + /* + * We boost task t by manufacturing an rt_mutex that appears to + * be held by task t. We leave a pointer to that rt_mutex where + * task t can find it, and task t will release the mutex when it + * exits its outermost RCU read-side critical section. Then + * simply acquiring this artificial rt_mutex will boost task + * t's priority. (Thanks to tglx for suggesting this approach!) + * + * Note that task t must acquire rnp->lock to remove itself from + * the ->blkd_tasks list, which it will do from exit() if from + * nowhere else. We therefore are guaranteed that task t will + * stay around at least until we drop rnp->lock. Note that + * rnp->lock also resolves races between our priority boosting + * and task t's exiting its outermost RCU read-side critical + * section. + */ + t = container_of(tb, struct task_struct, rcu_node_entry); + rt_mutex_init_proxy_locked(&mtx, t); + t->rcu_boost_mutex = &mtx; + t->rcu_read_unlock_special |= RCU_READ_UNLOCK_BOOSTED; + raw_spin_unlock_irqrestore(&rnp->lock, flags); + rt_mutex_lock(&mtx); /* Side effect: boosts task t's priority. */ + rt_mutex_unlock(&mtx); /* Keep lockdep happy. */ + + return rnp->exp_tasks != NULL || rnp->boost_tasks != NULL; +} + +/* + * Timer handler to initiate waking up of boost kthreads that + * have yielded the CPU due to excessive numbers of tasks to + * boost. We wake up the per-rcu_node kthread, which in turn + * will wake up the booster kthread. + */ +static void rcu_boost_kthread_timer(unsigned long arg) +{ + unsigned long flags; + struct rcu_node *rnp = (struct rcu_node *)arg; + + raw_spin_lock_irqsave(&rnp->lock, flags); + invoke_rcu_node_kthread(rnp); + raw_spin_unlock_irqrestore(&rnp->lock, flags); +} + +/* + * Priority-boosting kthread. One per leaf rcu_node and one for the + * root rcu_node. + */ +static int rcu_boost_kthread(void *arg) +{ + struct rcu_node *rnp = (struct rcu_node *)arg; + int spincnt = 0; + int more2boost; + + for (;;) { + wait_event_interruptible(rnp->boost_wq, rnp->boost_tasks || + rnp->exp_tasks || + kthread_should_stop()); + if (kthread_should_stop()) + break; + more2boost = rcu_boost(rnp); + if (more2boost) + spincnt++; + else + spincnt = 0; + if (spincnt > 10) { + rcu_yield(rcu_boost_kthread_timer, (unsigned long)rnp); + spincnt = 0; + } + } + return 0; +} + +/* + * Check to see if it is time to start boosting RCU readers that are + * blocking the current grace period, and, if so, tell the per-rcu_node + * kthread to start boosting them. If there is an expedited grace + * period in progress, it is always time to boost. + * + * The caller must hold rnp->lock. + */ +static void rcu_initiate_boost(struct rcu_node *rnp) +{ + struct task_struct *t; + + if (!rcu_preempt_blocked_readers_cgp(rnp) && rnp->exp_tasks == NULL) + return; + if (rnp->exp_tasks != NULL || + (rnp->gp_tasks != NULL && + rnp->boost_tasks == NULL && + rnp->qsmask == 0 && + ULONG_CMP_GE(jiffies, rnp->boost_time))) { + if (rnp->exp_tasks == NULL) + rnp->boost_tasks = rnp->gp_tasks; + t = rnp->boost_kthread_task; + if (t != NULL) + wake_up_process(t); + } +} + +static void rcu_boost_kthread_setaffinity(struct rcu_node *rnp, + cpumask_var_t cm) +{ + unsigned long flags; + struct task_struct *t; + + raw_spin_lock_irqsave(&rnp->lock, flags); + t = rnp->boost_kthread_task; + if (t != NULL) + set_cpus_allowed_ptr(rnp->boost_kthread_task, cm); + raw_spin_unlock_irqrestore(&rnp->lock, flags); +} + +#define RCU_BOOST_DELAY_JIFFIES DIV_ROUND_UP(CONFIG_RCU_BOOST_DELAY * HZ, 1000) + +/* + * Do priority-boost accounting for the start of a new grace period. + */ +static void rcu_preempt_boost_start_gp(struct rcu_node *rnp) +{ + rnp->boost_time = jiffies + RCU_BOOST_DELAY_JIFFIES; +} + +/* + * Initialize the RCU-boost waitqueue. + */ +static void __init rcu_init_boost_waitqueue(struct rcu_node *rnp) +{ + init_waitqueue_head(&rnp->boost_wq); +} + +/* + * Create an RCU-boost kthread for the specified node if one does not + * already exist. We only create this kthread for preemptible RCU. + * Returns zero if all is well, a negated errno otherwise. + */ +static int __cpuinit rcu_spawn_one_boost_kthread(struct rcu_state *rsp, + struct rcu_node *rnp, + int rnp_index) +{ + unsigned long flags; + struct sched_param sp; + struct task_struct *t; + + if (&rcu_preempt_state != rsp) + return 0; + if (rnp->boost_kthread_task != NULL) + return 0; + t = kthread_create(rcu_boost_kthread, (void *)rnp, + "rcub%d", rnp_index); + if (IS_ERR(t)) + return PTR_ERR(t); + raw_spin_lock_irqsave(&rnp->lock, flags); + rnp->boost_kthread_task = t; + raw_spin_unlock_irqrestore(&rnp->lock, flags); + wake_up_process(t); + sp.sched_priority = RCU_KTHREAD_PRIO; + sched_setscheduler_nocheck(t, SCHED_FIFO, &sp); + return 0; +} + +#ifdef CONFIG_HOTPLUG_CPU + +static void rcu_stop_boost_kthread(struct rcu_node *rnp) +{ + unsigned long flags; + struct task_struct *t; + + raw_spin_lock_irqsave(&rnp->lock, flags); + t = rnp->boost_kthread_task; + rnp->boost_kthread_task = NULL; + raw_spin_unlock_irqrestore(&rnp->lock, flags); + if (t != NULL) + kthread_stop(t); +} + +#endif /* #ifdef CONFIG_HOTPLUG_CPU */ + +#else /* #ifdef CONFIG_RCU_BOOST */ + +static void rcu_initiate_boost(struct rcu_node *rnp) +{ +} + +static void rcu_boost_kthread_setaffinity(struct rcu_node *rnp, + cpumask_var_t cm) +{ +} + +static void rcu_preempt_boost_start_gp(struct rcu_node *rnp) +{ +} + +static void __init rcu_init_boost_waitqueue(struct rcu_node *rnp) +{ +} + +static int __cpuinit rcu_spawn_one_boost_kthread(struct rcu_state *rsp, + struct rcu_node *rnp, + int rnp_index) +{ + return 0; +} + +#ifdef CONFIG_HOTPLUG_CPU + +static void rcu_stop_boost_kthread(struct rcu_node *rnp) +{ +} + +#endif /* #ifdef CONFIG_HOTPLUG_CPU */ + +#endif /* #else #ifdef CONFIG_RCU_BOOST */ + #ifndef CONFIG_SMP void synchronize_sched_expedited(void) @@ -1206,8 +1498,8 @@ static DEFINE_PER_CPU(unsigned long, rcu_dyntick_holdoff); * * Because it is not legal to invoke rcu_process_callbacks() with irqs * disabled, we do one pass of force_quiescent_state(), then do a - * invoke_rcu_kthread() to cause rcu_process_callbacks() to be invoked later. - * The per-cpu rcu_dyntick_drain variable controls the sequencing. + * invoke_rcu_cpu_kthread() to cause rcu_process_callbacks() to be invoked + * later. The per-cpu rcu_dyntick_drain variable controls the sequencing. */ int rcu_needs_cpu(int cpu) { @@ -1257,7 +1549,7 @@ int rcu_needs_cpu(int cpu) /* If RCU callbacks are still pending, RCU still needs this CPU. */ if (c) - invoke_rcu_kthread(); + invoke_rcu_cpu_kthread(); return c; } -- cgit v1.1 From 0f962a5e7277c34987b77dc82fc9aefcedc95e27 Mon Sep 17 00:00:00 2001 From: "Paul E. McKenney" Date: Thu, 14 Apr 2011 12:13:53 -0700 Subject: rcu: Force per-rcu_node kthreads off of the outgoing CPU The scheduler has had some heartburn in the past when too many real-time kthreads were affinitied to the outgoing CPU. So, this commit lightens the load by forcing the per-rcu_node and the boost kthreads off of the outgoing CPU. Note that RCU's per-CPU kthread remains on the outgoing CPU until the bitter end, as it must in order to preserve correctness. Also avoid disabling hardirqs across calls to set_cpus_allowed_ptr(), given that this function can block. Signed-off-by: Paul E. McKenney Signed-off-by: Paul E. McKenney --- kernel/rcutree.c | 24 +++++++++++++++++++----- kernel/rcutree_plugin.h | 8 +++++--- 2 files changed, 24 insertions(+), 8 deletions(-) (limited to 'kernel') diff --git a/kernel/rcutree.c b/kernel/rcutree.c index 28fd92a..51eef41 100644 --- a/kernel/rcutree.c +++ b/kernel/rcutree.c @@ -95,7 +95,7 @@ static DEFINE_PER_CPU(wait_queue_head_t, rcu_cpu_wq); static DEFINE_PER_CPU(char, rcu_cpu_has_work); static char rcu_kthreads_spawnable; -static void rcu_node_kthread_setaffinity(struct rcu_node *rnp); +static void rcu_node_kthread_setaffinity(struct rcu_node *rnp, int outgoingcpu); static void invoke_rcu_cpu_kthread(void); #define RCU_KTHREAD_PRIO 1 /* RT priority for per-CPU kthreads. */ @@ -1099,7 +1099,7 @@ static void __rcu_offline_cpu(int cpu, struct rcu_state *rsp) kthread_stop(t); rcu_stop_boost_kthread(rnp); } else - rcu_node_kthread_setaffinity(rnp); + rcu_node_kthread_setaffinity(rnp, -1); } /* @@ -1644,8 +1644,12 @@ static int rcu_node_kthread(void *arg) * Set the per-rcu_node kthread's affinity to cover all CPUs that are * served by the rcu_node in question. The CPU hotplug lock is still * held, so the value of rnp->qsmaskinit will be stable. + * + * We don't include outgoingcpu in the affinity set, use -1 if there is + * no outgoing CPU. If there are no CPUs left in the affinity set, + * this function allows the kthread to execute on any CPU. */ -static void rcu_node_kthread_setaffinity(struct rcu_node *rnp) +static void rcu_node_kthread_setaffinity(struct rcu_node *rnp, int outgoingcpu) { cpumask_var_t cm; int cpu; @@ -1657,8 +1661,14 @@ static void rcu_node_kthread_setaffinity(struct rcu_node *rnp) return; cpumask_clear(cm); for (cpu = rnp->grplo; cpu <= rnp->grphi; cpu++, mask >>= 1) - if (mask & 0x1) + if ((mask & 0x1) && cpu != outgoingcpu) cpumask_set_cpu(cpu, cm); + if (cpumask_weight(cm) == 0) { + cpumask_setall(cm); + for (cpu = rnp->grplo; cpu <= rnp->grphi; cpu++) + cpumask_clear_cpu(cpu, cm); + WARN_ON_ONCE(cpumask_weight(cm) == 0); + } set_cpus_allowed_ptr(rnp->node_kthread_task, cm); rcu_boost_kthread_setaffinity(rnp, cm); free_cpumask_var(cm); @@ -2154,7 +2164,11 @@ static int __cpuinit rcu_cpu_notify(struct notifier_block *self, rcu_online_kthreads(cpu); break; case CPU_ONLINE: - rcu_node_kthread_setaffinity(rnp); + case CPU_DOWN_FAILED: + rcu_node_kthread_setaffinity(rnp, -1); + break; + case CPU_DOWN_PREPARE: + rcu_node_kthread_setaffinity(rnp, cpu); break; case CPU_DYING: case CPU_DYING_FROZEN: diff --git a/kernel/rcutree_plugin.h b/kernel/rcutree_plugin.h index 5964f82..4e48625 100644 --- a/kernel/rcutree_plugin.h +++ b/kernel/rcutree_plugin.h @@ -1212,17 +1212,19 @@ static void rcu_initiate_boost(struct rcu_node *rnp) } } +/* + * Set the affinity of the boost kthread. The CPU-hotplug locks are + * held, so no one should be messing with the existence of the boost + * kthread. + */ static void rcu_boost_kthread_setaffinity(struct rcu_node *rnp, cpumask_var_t cm) { - unsigned long flags; struct task_struct *t; - raw_spin_lock_irqsave(&rnp->lock, flags); t = rnp->boost_kthread_task; if (t != NULL) set_cpus_allowed_ptr(rnp->boost_kthread_task, cm); - raw_spin_unlock_irqrestore(&rnp->lock, flags); } #define RCU_BOOST_DELAY_JIFFIES DIV_ROUND_UP(CONFIG_RCU_BOOST_DELAY * HZ, 1000) -- cgit v1.1 From e3995a25fa361ce987a7d0ade00b17e3151519d7 Mon Sep 17 00:00:00 2001 From: "Paul E. McKenney" Date: Mon, 18 Apr 2011 15:31:26 -0700 Subject: rcu: put per-CPU kthread at non-RT priority during CPU hotplug operations If you are doing CPU hotplug operations, it is best not to have CPU-bound realtime tasks running CPU-bound on the outgoing CPU. So this commit makes per-CPU kthreads run at non-realtime priority during that time. Signed-off-by: Paul E. McKenney Signed-off-by: Paul E. McKenney Reviewed-by: Josh Triplett --- kernel/rcutree.c | 26 ++++++++++++++++++++++++++ 1 file changed, 26 insertions(+) (limited to 'kernel') diff --git a/kernel/rcutree.c b/kernel/rcutree.c index 51eef41..198e4df 100644 --- a/kernel/rcutree.c +++ b/kernel/rcutree.c @@ -1464,6 +1464,30 @@ static void invoke_rcu_node_kthread(struct rcu_node *rnp) } /* + * Set the specified CPU's kthread to run RT or not, as specified by + * the to_rt argument. The CPU-hotplug locks are held, so the task + * is not going away. + */ +static void rcu_cpu_kthread_setrt(int cpu, int to_rt) +{ + int policy; + struct sched_param sp; + struct task_struct *t; + + t = per_cpu(rcu_cpu_kthread_task, cpu); + if (t == NULL) + return; + if (to_rt) { + policy = SCHED_FIFO; + sp.sched_priority = RCU_KTHREAD_PRIO; + } else { + policy = SCHED_NORMAL; + sp.sched_priority = 0; + } + sched_setscheduler_nocheck(t, policy, &sp); +} + +/* * Timer handler to initiate the waking up of per-CPU kthreads that * have yielded the CPU due to excess numbers of RCU callbacks. * We wake up the per-rcu_node kthread, which in turn will wake up @@ -2166,9 +2190,11 @@ static int __cpuinit rcu_cpu_notify(struct notifier_block *self, case CPU_ONLINE: case CPU_DOWN_FAILED: rcu_node_kthread_setaffinity(rnp, -1); + rcu_cpu_kthread_setrt(cpu, 1); break; case CPU_DOWN_PREPARE: rcu_node_kthread_setaffinity(rnp, cpu); + rcu_cpu_kthread_setrt(cpu, 0); break; case CPU_DYING: case CPU_DYING_FROZEN: -- cgit v1.1 From 3acf4a9a3d63f23430f940842829175b0778a1b8 Mon Sep 17 00:00:00 2001 From: "Paul E. McKenney" Date: Sun, 17 Apr 2011 23:45:23 -0700 Subject: rcu: avoid hammering sched with yet another bound RT kthread The scheduler does not appear to take kindly to having multiple real-time threads bound to a CPU that is going offline. So this commit is a temporary hack-around to avoid that happening. Signed-off-by: Paul E. McKenney Signed-off-by: Paul E. McKenney --- kernel/rcutorture.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) (limited to 'kernel') diff --git a/kernel/rcutorture.c b/kernel/rcutorture.c index c224da4..4d256db 100644 --- a/kernel/rcutorture.c +++ b/kernel/rcutorture.c @@ -163,11 +163,11 @@ static int stutter_pause_test; #endif int rcutorture_runnable = RCUTORTURE_RUNNABLE_INIT; -#ifdef CONFIG_RCU_BOOST +#if defined(CONFIG_RCU_BOOST) && !defined(CONFIG_HOTPLUG_CPU) #define rcu_can_boost() 1 -#else /* #ifdef CONFIG_RCU_BOOST */ +#else /* #if defined(CONFIG_RCU_BOOST) && !defined(CONFIG_HOTPLUG_CPU) */ #define rcu_can_boost() 0 -#endif /* #else #ifdef CONFIG_RCU_BOOST */ +#endif /* #else #if defined(CONFIG_RCU_BOOST) && !defined(CONFIG_HOTPLUG_CPU) */ static unsigned long boost_starttime; /* jiffies of next boost test start. */ DEFINE_MUTEX(boost_mutex); /* protect setting boost_starttime */ -- cgit v1.1 From 67b98dba474f293c389fc2b7254dcf7c0492e3bd Mon Sep 17 00:00:00 2001 From: "Paul E. McKenney" Date: Mon, 21 Feb 2011 13:31:55 -0800 Subject: rcu: eliminate unused boosting statistics The n_rcu_torture_boost_allocerror and n_rcu_torture_boost_afferror statistics are not actually incremented anymore, so eliminate them. Signed-off-by: Paul E. McKenney Signed-off-by: Paul E. McKenney Reviewed-by: Josh Triplett --- kernel/rcutorture.c | 10 +--------- 1 file changed, 1 insertion(+), 9 deletions(-) (limited to 'kernel') diff --git a/kernel/rcutorture.c b/kernel/rcutorture.c index 4d256db..22b0e74 100644 --- a/kernel/rcutorture.c +++ b/kernel/rcutorture.c @@ -146,8 +146,6 @@ static atomic_t n_rcu_torture_mberror; static atomic_t n_rcu_torture_error; static long n_rcu_torture_boost_ktrerror; static long n_rcu_torture_boost_rterror; -static long n_rcu_torture_boost_allocerror; -static long n_rcu_torture_boost_afferror; static long n_rcu_torture_boost_failure; static long n_rcu_torture_boosts; static long n_rcu_torture_timers; @@ -1067,7 +1065,7 @@ rcu_torture_printk(char *page) cnt += sprintf(&page[cnt], "%s%s ", torture_type, TORTURE_FLAG); cnt += sprintf(&page[cnt], "rtc: %p ver: %ld tfle: %d rta: %d rtaf: %d rtf: %d " - "rtmbe: %d rtbke: %ld rtbre: %ld rtbae: %ld rtbafe: %ld " + "rtmbe: %d rtbke: %ld rtbre: %ld " "rtbf: %ld rtb: %ld nt: %ld", rcu_torture_current, rcu_torture_current_version, @@ -1078,16 +1076,12 @@ rcu_torture_printk(char *page) atomic_read(&n_rcu_torture_mberror), n_rcu_torture_boost_ktrerror, n_rcu_torture_boost_rterror, - n_rcu_torture_boost_allocerror, - n_rcu_torture_boost_afferror, n_rcu_torture_boost_failure, n_rcu_torture_boosts, n_rcu_torture_timers); if (atomic_read(&n_rcu_torture_mberror) != 0 || n_rcu_torture_boost_ktrerror != 0 || n_rcu_torture_boost_rterror != 0 || - n_rcu_torture_boost_allocerror != 0 || - n_rcu_torture_boost_afferror != 0 || n_rcu_torture_boost_failure != 0) cnt += sprintf(&page[cnt], " !!!"); cnt += sprintf(&page[cnt], "\n%s%s ", torture_type, TORTURE_FLAG); @@ -1486,8 +1480,6 @@ rcu_torture_init(void) atomic_set(&n_rcu_torture_error, 0); n_rcu_torture_boost_ktrerror = 0; n_rcu_torture_boost_rterror = 0; - n_rcu_torture_boost_allocerror = 0; - n_rcu_torture_boost_afferror = 0; n_rcu_torture_boost_failure = 0; n_rcu_torture_boosts = 0; for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++) -- cgit v1.1 From 0ea1f2ebeb217d38770aebf91c4ecaa8e01b3305 Mon Sep 17 00:00:00 2001 From: "Paul E. McKenney" Date: Tue, 22 Feb 2011 13:42:43 -0800 Subject: rcu: Add boosting to TREE_PREEMPT_RCU tracing Includes total number of tasks boosted, number boosted on behalf of each of normal and expedited grace periods, and statistics on attempts to initiate boosting that failed for various reasons. Signed-off-by: Paul E. McKenney Signed-off-by: Paul E. McKenney Reviewed-by: Josh Triplett --- kernel/rcutree.h | 19 ++++++++++++++ kernel/rcutree_plugin.h | 42 +++++++++++++++++++++++++++--- kernel/rcutree_trace.c | 68 +++++++++++++++++++++++++++++++++++++++++++++++++ 3 files changed, 125 insertions(+), 4 deletions(-) (limited to 'kernel') diff --git a/kernel/rcutree.h b/kernel/rcutree.h index 8db0cdc..d49046c 100644 --- a/kernel/rcutree.h +++ b/kernel/rcutree.h @@ -152,6 +152,25 @@ struct rcu_node { wait_queue_head_t boost_wq; /* Wait queue on which to park the boost */ /* kthread. */ + unsigned long n_tasks_boosted; + /* Total number of tasks boosted. */ + unsigned long n_exp_boosts; + /* Number of tasks boosted for expedited GP. */ + unsigned long n_normal_boosts; + /* Number of tasks boosted for normal GP. */ + unsigned long n_balk_blkd_tasks; + /* Refused to boost: no blocked tasks. */ + unsigned long n_balk_exp_gp_tasks; + /* Refused to boost: nothing blocking GP. */ + unsigned long n_balk_boost_tasks; + /* Refused to boost: already boosting. */ + unsigned long n_balk_notblocked; + /* Refused to boost: RCU RS CS still running. */ + unsigned long n_balk_notyet; + /* Refused to boost: not yet time. */ + unsigned long n_balk_nos; + /* Refused to boost: not sure why, though. */ + /* This can happen due to race conditions. */ #endif /* #ifdef CONFIG_RCU_BOOST */ struct task_struct *node_kthread_task; /* kthread that takes care of this rcu_node */ diff --git a/kernel/rcutree_plugin.h b/kernel/rcutree_plugin.h index 4e48625..07d3464 100644 --- a/kernel/rcutree_plugin.h +++ b/kernel/rcutree_plugin.h @@ -1073,6 +1073,33 @@ static void __init __rcu_init_preempt(void) #include "rtmutex_common.h" +#ifdef CONFIG_RCU_TRACE + +static void rcu_initiate_boost_trace(struct rcu_node *rnp) +{ + if (list_empty(&rnp->blkd_tasks)) + rnp->n_balk_blkd_tasks++; + else if (rnp->exp_tasks == NULL && rnp->gp_tasks == NULL) + rnp->n_balk_exp_gp_tasks++; + else if (rnp->gp_tasks != NULL && rnp->boost_tasks != NULL) + rnp->n_balk_boost_tasks++; + else if (rnp->gp_tasks != NULL && rnp->qsmask != 0) + rnp->n_balk_notblocked++; + else if (rnp->gp_tasks != NULL && + ULONG_CMP_GE(jiffies, rnp->boost_time)) + rnp->n_balk_notyet++; + else + rnp->n_balk_nos++; +} + +#else /* #ifdef CONFIG_RCU_TRACE */ + +static void rcu_initiate_boost_trace(struct rcu_node *rnp) +{ +} + +#endif /* #else #ifdef CONFIG_RCU_TRACE */ + /* * Carry out RCU priority boosting on the task indicated by ->exp_tasks * or ->boost_tasks, advancing the pointer to the next task in the @@ -1108,10 +1135,14 @@ static int rcu_boost(struct rcu_node *rnp) * expedited grace period must boost all blocked tasks, including * those blocking the pre-existing normal grace period. */ - if (rnp->exp_tasks != NULL) + if (rnp->exp_tasks != NULL) { tb = rnp->exp_tasks; - else + rnp->n_exp_boosts++; + } else { tb = rnp->boost_tasks; + rnp->n_normal_boosts++; + } + rnp->n_tasks_boosted++; /* * We boost task t by manufacturing an rt_mutex that appears to @@ -1197,8 +1228,10 @@ static void rcu_initiate_boost(struct rcu_node *rnp) { struct task_struct *t; - if (!rcu_preempt_blocked_readers_cgp(rnp) && rnp->exp_tasks == NULL) + if (!rcu_preempt_blocked_readers_cgp(rnp) && rnp->exp_tasks == NULL) { + rnp->n_balk_exp_gp_tasks++; return; + } if (rnp->exp_tasks != NULL || (rnp->gp_tasks != NULL && rnp->boost_tasks == NULL && @@ -1209,7 +1242,8 @@ static void rcu_initiate_boost(struct rcu_node *rnp) t = rnp->boost_kthread_task; if (t != NULL) wake_up_process(t); - } + } else + rcu_initiate_boost_trace(rnp); } /* diff --git a/kernel/rcutree_trace.c b/kernel/rcutree_trace.c index 1cedf94..ead5736 100644 --- a/kernel/rcutree_trace.c +++ b/kernel/rcutree_trace.c @@ -157,6 +157,71 @@ static const struct file_operations rcudata_csv_fops = { .release = single_release, }; +#ifdef CONFIG_RCU_BOOST + +static void print_one_rcu_node_boost(struct seq_file *m, struct rcu_node *rnp) +{ + seq_printf(m, "%d:%d tasks=%c%c%c%c ntb=%lu neb=%lu nnb=%lu " + "j=%04x bt=%04x\n", + rnp->grplo, rnp->grphi, + "T."[list_empty(&rnp->blkd_tasks)], + "N."[!rnp->gp_tasks], + "E."[!rnp->exp_tasks], + "B."[!rnp->boost_tasks], + rnp->n_tasks_boosted, rnp->n_exp_boosts, + rnp->n_normal_boosts, + (int)(jiffies & 0xffff), + (int)(rnp->boost_time & 0xffff)); + seq_printf(m, "%s: nt=%lu egt=%lu bt=%lu nb=%lu ny=%lu nos=%lu\n", + " balk", + rnp->n_balk_blkd_tasks, + rnp->n_balk_exp_gp_tasks, + rnp->n_balk_boost_tasks, + rnp->n_balk_notblocked, + rnp->n_balk_notyet, + rnp->n_balk_nos); +} + +static int show_rcu_node_boost(struct seq_file *m, void *unused) +{ + struct rcu_node *rnp; + + rcu_for_each_leaf_node(&rcu_preempt_state, rnp) + print_one_rcu_node_boost(m, rnp); + return 0; +} + +static int rcu_node_boost_open(struct inode *inode, struct file *file) +{ + return single_open(file, show_rcu_node_boost, NULL); +} + +static const struct file_operations rcu_node_boost_fops = { + .owner = THIS_MODULE, + .open = rcu_node_boost_open, + .read = seq_read, + .llseek = seq_lseek, + .release = single_release, +}; + +/* + * Create the rcuboost debugfs entry. Standard error return. + */ +static int rcu_boost_trace_create_file(struct dentry *rcudir) +{ + return !debugfs_create_file("rcuboost", 0444, rcudir, NULL, + &rcu_node_boost_fops); +} + +#else /* #ifdef CONFIG_RCU_BOOST */ + +static int rcu_boost_trace_create_file(struct dentry *rcudir) +{ + return 0; /* There cannot be an error if we didn't create it! */ +} + +#endif /* #else #ifdef CONFIG_RCU_BOOST */ + static void print_one_rcu_state(struct seq_file *m, struct rcu_state *rsp) { unsigned long gpnum; @@ -315,6 +380,9 @@ static int __init rcutree_trace_init(void) if (!retval) goto free_out; + if (rcu_boost_trace_create_file(rcudir)) + goto free_out; + retval = debugfs_create_file("rcugp", 0444, rcudir, NULL, &rcugp_fops); if (!retval) goto free_out; -- cgit v1.1 From 0ac3d136b2e3cdf1161178223bc5da14a06241d0 Mon Sep 17 00:00:00 2001 From: "Paul E. McKenney" Date: Mon, 28 Mar 2011 15:47:07 -0700 Subject: rcu: add callback-queue information to rcudata output This commit adds an indication of the state of the callback queue using a string of four characters following the "ql=" integer queue length. The first character is "N" if there are callbacks that have been queued that are not yet ready to be handled by the next grace period, or "." otherwise. The second character is "R" if there are callbacks queued that are ready to be handled by the next grace period, or "." otherwise. The third character is "W" if there are callbacks waiting for the current grace period, or "." otherwise. Finally, the fourth character is "D" if there are callbacks that have been handled by a prior grace period and are waiting to be invoked, or ".". Note that callbacks that are in the process of being invoked are not shown. These callbacks would have been removed from the rcu_data structure's list by rcu_do_batch() prior to being executed. (These callbacks are also not reflected in the "ql=" total, FWIW.) Also, document the new callback-queue trace information. Signed-off-by: Paul E. McKenney Signed-off-by: Paul E. McKenney Reviewed-by: Josh Triplett --- kernel/rcutree_trace.c | 21 +++++++++++++++++++-- 1 file changed, 19 insertions(+), 2 deletions(-) (limited to 'kernel') diff --git a/kernel/rcutree_trace.c b/kernel/rcutree_trace.c index ead5736..afd262f 100644 --- a/kernel/rcutree_trace.c +++ b/kernel/rcutree_trace.c @@ -64,7 +64,16 @@ static void print_one_rcu_data(struct seq_file *m, struct rcu_data *rdp) rdp->dynticks_fqs); #endif /* #ifdef CONFIG_NO_HZ */ seq_printf(m, " of=%lu ri=%lu", rdp->offline_fqs, rdp->resched_ipi); - seq_printf(m, " ql=%ld b=%ld", rdp->qlen, rdp->blimit); + seq_printf(m, " ql=%ld qs=%c%c%c%c b=%ld", + rdp->qlen, + ".N"[rdp->nxttail[RCU_NEXT_READY_TAIL] != + rdp->nxttail[RCU_NEXT_TAIL]], + ".R"[rdp->nxttail[RCU_WAIT_TAIL] != + rdp->nxttail[RCU_NEXT_READY_TAIL]], + ".W"[rdp->nxttail[RCU_DONE_TAIL] != + rdp->nxttail[RCU_WAIT_TAIL]], + ".D"[&rdp->nxtlist != rdp->nxttail[RCU_DONE_TAIL]], + rdp->blimit); seq_printf(m, " ci=%lu co=%lu ca=%lu\n", rdp->n_cbs_invoked, rdp->n_cbs_orphaned, rdp->n_cbs_adopted); } @@ -121,7 +130,15 @@ static void print_one_rcu_data_csv(struct seq_file *m, struct rcu_data *rdp) rdp->dynticks_fqs); #endif /* #ifdef CONFIG_NO_HZ */ seq_printf(m, ",%lu,%lu", rdp->offline_fqs, rdp->resched_ipi); - seq_printf(m, ",%ld,%ld", rdp->qlen, rdp->blimit); + seq_printf(m, ",%ld,\"%c%c%c%c\",%ld", rdp->qlen, + ".N"[rdp->nxttail[RCU_NEXT_READY_TAIL] != + rdp->nxttail[RCU_NEXT_TAIL]], + ".R"[rdp->nxttail[RCU_WAIT_TAIL] != + rdp->nxttail[RCU_NEXT_READY_TAIL]], + ".W"[rdp->nxttail[RCU_DONE_TAIL] != + rdp->nxttail[RCU_WAIT_TAIL]], + ".D"[&rdp->nxtlist != rdp->nxttail[RCU_DONE_TAIL]], + rdp->blimit); seq_printf(m, ",%lu,%lu,%lu\n", rdp->n_cbs_invoked, rdp->n_cbs_orphaned, rdp->n_cbs_adopted); } -- cgit v1.1 From d71df90eadfc35aa549ff9a850842673febca71f Mon Sep 17 00:00:00 2001 From: "Paul E. McKenney" Date: Tue, 29 Mar 2011 17:48:28 -0700 Subject: rcu: add tracing for RCU's kthread run states. Add tracing to help debugging situations when RCU's kthreads are not running but are supposed to be. Signed-off-by: Paul E. McKenney Signed-off-by: Paul E. McKenney Reviewed-by: Josh Triplett --- kernel/rcutree.c | 11 ++++++++++- kernel/rcutree.h | 11 +++++++++++ kernel/rcutree_plugin.h | 3 +++ kernel/rcutree_trace.c | 23 ++++++++++++++++++++--- 4 files changed, 44 insertions(+), 4 deletions(-) (limited to 'kernel') diff --git a/kernel/rcutree.c b/kernel/rcutree.c index 198e4df..d891740 100644 --- a/kernel/rcutree.c +++ b/kernel/rcutree.c @@ -91,8 +91,9 @@ EXPORT_SYMBOL_GPL(rcu_scheduler_active); * handle all flavors of RCU. */ static DEFINE_PER_CPU(struct task_struct *, rcu_cpu_kthread_task); +DEFINE_PER_CPU(unsigned int, rcu_cpu_kthread_status); static DEFINE_PER_CPU(wait_queue_head_t, rcu_cpu_wq); -static DEFINE_PER_CPU(char, rcu_cpu_has_work); +DEFINE_PER_CPU(char, rcu_cpu_has_work); static char rcu_kthreads_spawnable; static void rcu_node_kthread_setaffinity(struct rcu_node *rnp, int outgoingcpu); @@ -1563,11 +1564,13 @@ static int rcu_cpu_kthread(void *arg) int cpu = (int)(long)arg; unsigned long flags; int spincnt = 0; + unsigned int *statusp = &per_cpu(rcu_cpu_kthread_status, cpu); wait_queue_head_t *wqp = &per_cpu(rcu_cpu_wq, cpu); char work; char *workp = &per_cpu(rcu_cpu_has_work, cpu); for (;;) { + *statusp = RCU_KTHREAD_WAITING; wait_event_interruptible(*wqp, *workp != 0 || kthread_should_stop()); local_bh_disable(); @@ -1575,6 +1578,7 @@ static int rcu_cpu_kthread(void *arg) local_bh_enable(); break; } + *statusp = RCU_KTHREAD_RUNNING; local_irq_save(flags); work = *workp; *workp = 0; @@ -1587,10 +1591,12 @@ static int rcu_cpu_kthread(void *arg) else spincnt = 0; if (spincnt > 10) { + *statusp = RCU_KTHREAD_YIELDING; rcu_yield(rcu_cpu_kthread_timer, (unsigned long)cpu); spincnt = 0; } } + *statusp = RCU_KTHREAD_STOPPED; return 0; } @@ -1637,10 +1643,12 @@ static int rcu_node_kthread(void *arg) struct task_struct *t; for (;;) { + rnp->node_kthread_status = RCU_KTHREAD_WAITING; wait_event_interruptible(rnp->node_wq, rnp->wakemask != 0 || kthread_should_stop()); if (kthread_should_stop()) break; + rnp->node_kthread_status = RCU_KTHREAD_RUNNING; raw_spin_lock_irqsave(&rnp->lock, flags); mask = rnp->wakemask; rnp->wakemask = 0; @@ -1661,6 +1669,7 @@ static int rcu_node_kthread(void *arg) preempt_enable(); } } + rnp->node_kthread_status = RCU_KTHREAD_STOPPED; return 0; } diff --git a/kernel/rcutree.h b/kernel/rcutree.h index d49046c..67341db 100644 --- a/kernel/rcutree.h +++ b/kernel/rcutree.h @@ -89,6 +89,13 @@ struct rcu_dynticks { atomic_t dynticks; /* Even value for dynticks-idle, else odd. */ }; +/* RCU's kthread states for tracing. */ +#define RCU_KTHREAD_STOPPED 0 +#define RCU_KTHREAD_RUNNING 1 +#define RCU_KTHREAD_WAITING 2 +#define RCU_KTHREAD_YIELDING 3 +#define RCU_KTHREAD_MAX 3 + /* * Definition for node within the RCU grace-period-detection hierarchy. */ @@ -152,6 +159,8 @@ struct rcu_node { wait_queue_head_t boost_wq; /* Wait queue on which to park the boost */ /* kthread. */ + unsigned int boost_kthread_status; + /* State of boost_kthread_task for tracing. */ unsigned long n_tasks_boosted; /* Total number of tasks boosted. */ unsigned long n_exp_boosts; @@ -179,6 +188,8 @@ struct rcu_node { wait_queue_head_t node_wq; /* Wait queue on which to park the per-node */ /* kthread. */ + unsigned int node_kthread_status; + /* State of node_kthread_task for tracing. */ } ____cacheline_internodealigned_in_smp; /* diff --git a/kernel/rcutree_plugin.h b/kernel/rcutree_plugin.h index 07d3464..22a6a46 100644 --- a/kernel/rcutree_plugin.h +++ b/kernel/rcutree_plugin.h @@ -1198,11 +1198,13 @@ static int rcu_boost_kthread(void *arg) int more2boost; for (;;) { + rnp->boost_kthread_status = RCU_KTHREAD_WAITING; wait_event_interruptible(rnp->boost_wq, rnp->boost_tasks || rnp->exp_tasks || kthread_should_stop()); if (kthread_should_stop()) break; + rnp->boost_kthread_status = RCU_KTHREAD_RUNNING; more2boost = rcu_boost(rnp); if (more2boost) spincnt++; @@ -1213,6 +1215,7 @@ static int rcu_boost_kthread(void *arg) spincnt = 0; } } + rnp->boost_kthread_status = RCU_KTHREAD_STOPPED; return 0; } diff --git a/kernel/rcutree_trace.c b/kernel/rcutree_trace.c index afd262f..fc40e89 100644 --- a/kernel/rcutree_trace.c +++ b/kernel/rcutree_trace.c @@ -46,6 +46,16 @@ #define RCU_TREE_NONCORE #include "rcutree.h" +DECLARE_PER_CPU(unsigned int, rcu_cpu_kthread_status); +DECLARE_PER_CPU(char, rcu_cpu_has_work); + +static char convert_kthread_status(unsigned int kthread_status) +{ + if (kthread_status > RCU_KTHREAD_MAX) + return '?'; + return "SRWY"[kthread_status]; +} + static void print_one_rcu_data(struct seq_file *m, struct rcu_data *rdp) { if (!rdp->beenonline) @@ -64,7 +74,7 @@ static void print_one_rcu_data(struct seq_file *m, struct rcu_data *rdp) rdp->dynticks_fqs); #endif /* #ifdef CONFIG_NO_HZ */ seq_printf(m, " of=%lu ri=%lu", rdp->offline_fqs, rdp->resched_ipi); - seq_printf(m, " ql=%ld qs=%c%c%c%c b=%ld", + seq_printf(m, " ql=%ld qs=%c%c%c%c kt=%d/%c b=%ld", rdp->qlen, ".N"[rdp->nxttail[RCU_NEXT_READY_TAIL] != rdp->nxttail[RCU_NEXT_TAIL]], @@ -73,6 +83,9 @@ static void print_one_rcu_data(struct seq_file *m, struct rcu_data *rdp) ".W"[rdp->nxttail[RCU_DONE_TAIL] != rdp->nxttail[RCU_WAIT_TAIL]], ".D"[&rdp->nxtlist != rdp->nxttail[RCU_DONE_TAIL]], + per_cpu(rcu_cpu_has_work, rdp->cpu), + convert_kthread_status(per_cpu(rcu_cpu_kthread_status, + rdp->cpu)), rdp->blimit); seq_printf(m, " ci=%lu co=%lu ca=%lu\n", rdp->n_cbs_invoked, rdp->n_cbs_orphaned, rdp->n_cbs_adopted); @@ -130,7 +143,7 @@ static void print_one_rcu_data_csv(struct seq_file *m, struct rcu_data *rdp) rdp->dynticks_fqs); #endif /* #ifdef CONFIG_NO_HZ */ seq_printf(m, ",%lu,%lu", rdp->offline_fqs, rdp->resched_ipi); - seq_printf(m, ",%ld,\"%c%c%c%c\",%ld", rdp->qlen, + seq_printf(m, ",%ld,\"%c%c%c%c\",%d,\"%c\",%ld", rdp->qlen, ".N"[rdp->nxttail[RCU_NEXT_READY_TAIL] != rdp->nxttail[RCU_NEXT_TAIL]], ".R"[rdp->nxttail[RCU_WAIT_TAIL] != @@ -138,6 +151,9 @@ static void print_one_rcu_data_csv(struct seq_file *m, struct rcu_data *rdp) ".W"[rdp->nxttail[RCU_DONE_TAIL] != rdp->nxttail[RCU_WAIT_TAIL]], ".D"[&rdp->nxtlist != rdp->nxttail[RCU_DONE_TAIL]], + per_cpu(rcu_cpu_has_work, rdp->cpu), + convert_kthread_status(per_cpu(rcu_cpu_kthread_status, + rdp->cpu)), rdp->blimit); seq_printf(m, ",%lu,%lu,%lu\n", rdp->n_cbs_invoked, rdp->n_cbs_orphaned, rdp->n_cbs_adopted); @@ -178,13 +194,14 @@ static const struct file_operations rcudata_csv_fops = { static void print_one_rcu_node_boost(struct seq_file *m, struct rcu_node *rnp) { - seq_printf(m, "%d:%d tasks=%c%c%c%c ntb=%lu neb=%lu nnb=%lu " + seq_printf(m, "%d:%d tasks=%c%c%c%c kt=%c ntb=%lu neb=%lu nnb=%lu " "j=%04x bt=%04x\n", rnp->grplo, rnp->grphi, "T."[list_empty(&rnp->blkd_tasks)], "N."[!rnp->gp_tasks], "E."[!rnp->exp_tasks], "B."[!rnp->boost_tasks], + convert_kthread_status(rnp->boost_kthread_status), rnp->n_tasks_boosted, rnp->n_exp_boosts, rnp->n_normal_boosts, (int)(jiffies & 0xffff), -- cgit v1.1 From 4a29865689dbb87a02e3b0fff4a4ae5041273173 Mon Sep 17 00:00:00 2001 From: "Paul E. McKenney" Date: Sun, 3 Apr 2011 21:33:51 -0700 Subject: rcu: make rcutorture version numbers available through debugfs It is not possible to accurately correlate rcutorture output with that of debugfs. This patch therefore adds a debugfs file that prints out the rcutorture version number, permitting easy correlation. Signed-off-by: Paul E. McKenney Signed-off-by: Paul E. McKenney Reviewed-by: Josh Triplett --- kernel/rcutorture.c | 8 +++++--- kernel/rcutree.c | 37 +++++++++++++++++++++++++++++++++++++ kernel/rcutree_trace.c | 28 ++++++++++++++++++++++++++++ 3 files changed, 70 insertions(+), 3 deletions(-) (limited to 'kernel') diff --git a/kernel/rcutorture.c b/kernel/rcutorture.c index 22b0e74..c2f58ec 100644 --- a/kernel/rcutorture.c +++ b/kernel/rcutorture.c @@ -131,7 +131,7 @@ struct rcu_torture { static LIST_HEAD(rcu_torture_freelist); static struct rcu_torture __rcu *rcu_torture_current; -static long rcu_torture_current_version; +static unsigned long rcu_torture_current_version; static struct rcu_torture rcu_tortures[10 * RCU_TORTURE_PIPE_LEN]; static DEFINE_SPINLOCK(rcu_torture_lock); static DEFINE_PER_CPU(long [RCU_TORTURE_PIPE_LEN + 1], rcu_torture_count) = @@ -884,7 +884,7 @@ rcu_torture_writer(void *arg) old_rp->rtort_pipe_count++; cur_ops->deferred_free(old_rp); } - rcu_torture_current_version++; + rcutorture_record_progress(++rcu_torture_current_version); oldbatch = cur_ops->completed(); rcu_stutter_wait("rcu_torture_writer"); } while (!kthread_should_stop() && fullstop == FULLSTOP_DONTSTOP); @@ -1064,7 +1064,7 @@ rcu_torture_printk(char *page) } cnt += sprintf(&page[cnt], "%s%s ", torture_type, TORTURE_FLAG); cnt += sprintf(&page[cnt], - "rtc: %p ver: %ld tfle: %d rta: %d rtaf: %d rtf: %d " + "rtc: %p ver: %lu tfle: %d rta: %d rtaf: %d rtf: %d " "rtmbe: %d rtbke: %ld rtbre: %ld " "rtbf: %ld rtb: %ld nt: %ld", rcu_torture_current, @@ -1325,6 +1325,7 @@ rcu_torture_cleanup(void) int i; mutex_lock(&fullstop_mutex); + rcutorture_record_test_transition(); if (fullstop == FULLSTOP_SHUTDOWN) { printk(KERN_WARNING /* but going down anyway, so... */ "Concurrent 'rmmod rcutorture' and shutdown illegal!\n"); @@ -1616,6 +1617,7 @@ rcu_torture_init(void) } } register_reboot_notifier(&rcutorture_shutdown_nb); + rcutorture_record_test_transition(); mutex_unlock(&fullstop_mutex); return 0; diff --git a/kernel/rcutree.c b/kernel/rcutree.c index d891740..bb84dec 100644 --- a/kernel/rcutree.c +++ b/kernel/rcutree.c @@ -102,6 +102,18 @@ static void invoke_rcu_cpu_kthread(void); #define RCU_KTHREAD_PRIO 1 /* RT priority for per-CPU kthreads. */ /* + * Track the rcutorture test sequence number and the update version + * number within a given test. The rcutorture_testseq is incremented + * on every rcutorture module load and unload, so has an odd value + * when a test is running. The rcutorture_vernum is set to zero + * when rcutorture starts and is incremented on each rcutorture update. + * These variables enable correlating rcutorture output with the + * RCU tracing information. + */ +unsigned long rcutorture_testseq; +unsigned long rcutorture_vernum; + +/* * Return true if an RCU grace period is in progress. The ACCESS_ONCE()s * permit this function to be invoked without holding the root rcu_node * structure's ->lock, but of course results can be subject to change. @@ -193,6 +205,31 @@ void rcu_bh_force_quiescent_state(void) EXPORT_SYMBOL_GPL(rcu_bh_force_quiescent_state); /* + * Record the number of times rcutorture tests have been initiated and + * terminated. This information allows the debugfs tracing stats to be + * correlated to the rcutorture messages, even when the rcutorture module + * is being repeatedly loaded and unloaded. In other words, we cannot + * store this state in rcutorture itself. + */ +void rcutorture_record_test_transition(void) +{ + rcutorture_testseq++; + rcutorture_vernum = 0; +} +EXPORT_SYMBOL_GPL(rcutorture_record_test_transition); + +/* + * Record the number of writer passes through the current rcutorture test. + * This is also used to correlate debugfs tracing stats with the rcutorture + * messages. + */ +void rcutorture_record_progress(unsigned long vernum) +{ + rcutorture_vernum++; +} +EXPORT_SYMBOL_GPL(rcutorture_record_progress); + +/* * Force a quiescent state for RCU-sched. */ void rcu_sched_force_quiescent_state(void) diff --git a/kernel/rcutree_trace.c b/kernel/rcutree_trace.c index fc40e89..3baa235 100644 --- a/kernel/rcutree_trace.c +++ b/kernel/rcutree_trace.c @@ -394,6 +394,29 @@ static const struct file_operations rcu_pending_fops = { .release = single_release, }; +static int show_rcutorture(struct seq_file *m, void *unused) +{ + seq_printf(m, "rcutorture test sequence: %lu %s\n", + rcutorture_testseq >> 1, + (rcutorture_testseq & 0x1) ? "(test in progress)" : ""); + seq_printf(m, "rcutorture update version number: %lu\n", + rcutorture_vernum); + return 0; +} + +static int rcutorture_open(struct inode *inode, struct file *file) +{ + return single_open(file, show_rcutorture, NULL); +} + +static const struct file_operations rcutorture_fops = { + .owner = THIS_MODULE, + .open = rcutorture_open, + .read = seq_read, + .llseek = seq_lseek, + .release = single_release, +}; + static struct dentry *rcudir; static int __init rcutree_trace_init(void) @@ -430,6 +453,11 @@ static int __init rcutree_trace_init(void) NULL, &rcu_pending_fops); if (!retval) goto free_out; + + retval = debugfs_create_file("rcutorture", 0444, rcudir, + NULL, &rcutorture_fops); + if (!retval) + goto free_out; return 0; free_out: debugfs_remove_recursive(rcudir); -- cgit v1.1 From a9f4793d8900dc5dc09b3951bdcd4731290e06fe Mon Sep 17 00:00:00 2001 From: "Paul E. McKenney" Date: Mon, 2 May 2011 03:46:10 -0700 Subject: rcu: fix tracing bug thinko on boost-balk attribution The rcu_initiate_boost_trace() function mis-attributed refusals to initiate RCU priority boosting that were in fact due to its not yet being time to boost. This patch fixes the faulty comparison. Signed-off-by: Paul E. McKenney Signed-off-by: Paul E. McKenney --- kernel/rcutree_plugin.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'kernel') diff --git a/kernel/rcutree_plugin.h b/kernel/rcutree_plugin.h index 22a6a46..a21413d 100644 --- a/kernel/rcutree_plugin.h +++ b/kernel/rcutree_plugin.h @@ -1086,7 +1086,7 @@ static void rcu_initiate_boost_trace(struct rcu_node *rnp) else if (rnp->gp_tasks != NULL && rnp->qsmask != 0) rnp->n_balk_notblocked++; else if (rnp->gp_tasks != NULL && - ULONG_CMP_GE(jiffies, rnp->boost_time)) + ULONG_CMP_LT(jiffies, rnp->boost_time)) rnp->n_balk_notyet++; else rnp->n_balk_nos++; -- cgit v1.1 From 15ba0ba860871cf74b48b1bb47c26c91a66126f3 Mon Sep 17 00:00:00 2001 From: "Paul E. McKenney" Date: Wed, 6 Apr 2011 16:01:16 -0700 Subject: rcu: add grace-period age and more kthread state to tracing This commit adds the age in jiffies of the current grace period along with the duration in jiffies of the longest grace period since boot to the rcu/rcugp debugfs file. It also adds an additional "O" state to kthread tracing to differentiate between the kthread waiting due to having nothing to do on the one hand and waiting due to being on the wrong CPU on the other hand. Signed-off-by: Paul E. McKenney Signed-off-by: Paul E. McKenney --- kernel/rcutree.c | 10 ++++++++++ kernel/rcutree.h | 7 +++++-- kernel/rcutree_trace.c | 37 +++++++++++++++++++++++++++++-------- 3 files changed, 44 insertions(+), 10 deletions(-) (limited to 'kernel') diff --git a/kernel/rcutree.c b/kernel/rcutree.c index bb84dec..27b6d8d 100644 --- a/kernel/rcutree.c +++ b/kernel/rcutree.c @@ -92,6 +92,7 @@ EXPORT_SYMBOL_GPL(rcu_scheduler_active); */ static DEFINE_PER_CPU(struct task_struct *, rcu_cpu_kthread_task); DEFINE_PER_CPU(unsigned int, rcu_cpu_kthread_status); +DEFINE_PER_CPU(int, rcu_cpu_kthread_cpu); static DEFINE_PER_CPU(wait_queue_head_t, rcu_cpu_wq); DEFINE_PER_CPU(char, rcu_cpu_has_work); static char rcu_kthreads_spawnable; @@ -888,6 +889,8 @@ rcu_start_gp(struct rcu_state *rsp, unsigned long flags) static void rcu_report_qs_rsp(struct rcu_state *rsp, unsigned long flags) __releases(rcu_get_root(rsp)->lock) { + unsigned long gp_duration; + WARN_ON_ONCE(!rcu_gp_in_progress(rsp)); /* @@ -895,6 +898,9 @@ static void rcu_report_qs_rsp(struct rcu_state *rsp, unsigned long flags) * is seen before the assignment to rsp->completed. */ smp_mb(); /* See above block comment. */ + gp_duration = jiffies - rsp->gp_start; + if (gp_duration > rsp->gp_max) + rsp->gp_max = gp_duration; rsp->completed = rsp->gpnum; rsp->signaled = RCU_GP_IDLE; rcu_start_gp(rsp, flags); /* releases root node's rnp->lock. */ @@ -1583,12 +1589,15 @@ static int rcu_cpu_kthread_should_stop(int cpu) smp_processor_id() != cpu) { if (kthread_should_stop()) return 1; + per_cpu(rcu_cpu_kthread_status, cpu) = RCU_KTHREAD_OFFCPU; + per_cpu(rcu_cpu_kthread_cpu, cpu) = raw_smp_processor_id(); local_bh_enable(); schedule_timeout_uninterruptible(1); if (!cpumask_equal(¤t->cpus_allowed, cpumask_of(cpu))) set_cpus_allowed_ptr(current, cpumask_of(cpu)); local_bh_disable(); } + per_cpu(rcu_cpu_kthread_cpu, cpu) = cpu; return 0; } @@ -1656,6 +1665,7 @@ static int __cpuinit rcu_spawn_one_cpu_kthread(int cpu) if (IS_ERR(t)) return PTR_ERR(t); kthread_bind(t, cpu); + per_cpu(rcu_cpu_kthread_cpu, cpu) = cpu; WARN_ON_ONCE(per_cpu(rcu_cpu_kthread_task, cpu) != NULL); per_cpu(rcu_cpu_kthread_task, cpu) = t; wake_up_process(t); diff --git a/kernel/rcutree.h b/kernel/rcutree.h index 67341db..37502a2 100644 --- a/kernel/rcutree.h +++ b/kernel/rcutree.h @@ -93,8 +93,9 @@ struct rcu_dynticks { #define RCU_KTHREAD_STOPPED 0 #define RCU_KTHREAD_RUNNING 1 #define RCU_KTHREAD_WAITING 2 -#define RCU_KTHREAD_YIELDING 3 -#define RCU_KTHREAD_MAX 3 +#define RCU_KTHREAD_OFFCPU 3 +#define RCU_KTHREAD_YIELDING 4 +#define RCU_KTHREAD_MAX 4 /* * Definition for node within the RCU grace-period-detection hierarchy. @@ -383,6 +384,8 @@ struct rcu_state { /* but in jiffies. */ unsigned long jiffies_stall; /* Time at which to check */ /* for CPU stalls. */ + unsigned long gp_max; /* Maximum GP duration in */ + /* jiffies. */ char *name; /* Name of structure. */ }; diff --git a/kernel/rcutree_trace.c b/kernel/rcutree_trace.c index 3baa235..564b8fe 100644 --- a/kernel/rcutree_trace.c +++ b/kernel/rcutree_trace.c @@ -47,13 +47,14 @@ #include "rcutree.h" DECLARE_PER_CPU(unsigned int, rcu_cpu_kthread_status); +DECLARE_PER_CPU(unsigned int, rcu_cpu_kthread_cpu); DECLARE_PER_CPU(char, rcu_cpu_has_work); static char convert_kthread_status(unsigned int kthread_status) { if (kthread_status > RCU_KTHREAD_MAX) return '?'; - return "SRWY"[kthread_status]; + return "SRWOY"[kthread_status]; } static void print_one_rcu_data(struct seq_file *m, struct rcu_data *rdp) @@ -74,7 +75,7 @@ static void print_one_rcu_data(struct seq_file *m, struct rcu_data *rdp) rdp->dynticks_fqs); #endif /* #ifdef CONFIG_NO_HZ */ seq_printf(m, " of=%lu ri=%lu", rdp->offline_fqs, rdp->resched_ipi); - seq_printf(m, " ql=%ld qs=%c%c%c%c kt=%d/%c b=%ld", + seq_printf(m, " ql=%ld qs=%c%c%c%c kt=%d/%c/%d b=%ld", rdp->qlen, ".N"[rdp->nxttail[RCU_NEXT_READY_TAIL] != rdp->nxttail[RCU_NEXT_TAIL]], @@ -86,6 +87,7 @@ static void print_one_rcu_data(struct seq_file *m, struct rcu_data *rdp) per_cpu(rcu_cpu_has_work, rdp->cpu), convert_kthread_status(per_cpu(rcu_cpu_kthread_status, rdp->cpu)), + per_cpu(rcu_cpu_kthread_cpu, rdp->cpu), rdp->blimit); seq_printf(m, " ci=%lu co=%lu ca=%lu\n", rdp->n_cbs_invoked, rdp->n_cbs_orphaned, rdp->n_cbs_adopted); @@ -312,16 +314,35 @@ static const struct file_operations rcuhier_fops = { .release = single_release, }; +static void show_one_rcugp(struct seq_file *m, struct rcu_state *rsp) +{ + unsigned long flags; + unsigned long completed; + unsigned long gpnum; + unsigned long gpage; + unsigned long gpmax; + struct rcu_node *rnp = &rsp->node[0]; + + raw_spin_lock_irqsave(&rnp->lock, flags); + completed = rsp->completed; + gpnum = rsp->gpnum; + if (rsp->completed == rsp->gpnum) + gpage = 0; + else + gpage = jiffies - rsp->gp_start; + gpmax = rsp->gp_max; + raw_spin_unlock_irqrestore(&rnp->lock, flags); + seq_printf(m, "%s: completed=%ld gpnum=%lu age=%ld max=%ld\n", + rsp->name, completed, gpnum, gpage, gpmax); +} + static int show_rcugp(struct seq_file *m, void *unused) { #ifdef CONFIG_TREE_PREEMPT_RCU - seq_printf(m, "rcu_preempt: completed=%ld gpnum=%lu\n", - rcu_preempt_state.completed, rcu_preempt_state.gpnum); + show_one_rcugp(m, &rcu_preempt_state); #endif /* #ifdef CONFIG_TREE_PREEMPT_RCU */ - seq_printf(m, "rcu_sched: completed=%ld gpnum=%lu\n", - rcu_sched_state.completed, rcu_sched_state.gpnum); - seq_printf(m, "rcu_bh: completed=%ld gpnum=%lu\n", - rcu_bh_state.completed, rcu_bh_state.gpnum); + show_one_rcugp(m, &rcu_sched_state); + show_one_rcugp(m, &rcu_bh_state); return 0; } -- cgit v1.1 From 5ece5bab3ed8594ce2c85c6c6e6b82109db36ca7 Mon Sep 17 00:00:00 2001 From: "Paul E. McKenney" Date: Fri, 22 Apr 2011 18:08:51 -0700 Subject: rcu: Add forward-progress diagnostic for per-CPU kthreads Increment a per-CPU counter on each pass through rcu_cpu_kthread()'s service loop, and add it to the rcudata trace output. Signed-off-by: Paul E. McKenney Signed-off-by: Paul E. McKenney Reviewed-by: Josh Triplett --- kernel/rcutree.c | 2 ++ kernel/rcutree_trace.c | 4 +++- 2 files changed, 5 insertions(+), 1 deletion(-) (limited to 'kernel') diff --git a/kernel/rcutree.c b/kernel/rcutree.c index 27b6d8d..575d641 100644 --- a/kernel/rcutree.c +++ b/kernel/rcutree.c @@ -93,6 +93,7 @@ EXPORT_SYMBOL_GPL(rcu_scheduler_active); static DEFINE_PER_CPU(struct task_struct *, rcu_cpu_kthread_task); DEFINE_PER_CPU(unsigned int, rcu_cpu_kthread_status); DEFINE_PER_CPU(int, rcu_cpu_kthread_cpu); +DEFINE_PER_CPU(unsigned int, rcu_cpu_kthread_loops); static DEFINE_PER_CPU(wait_queue_head_t, rcu_cpu_wq); DEFINE_PER_CPU(char, rcu_cpu_has_work); static char rcu_kthreads_spawnable; @@ -1625,6 +1626,7 @@ static int rcu_cpu_kthread(void *arg) break; } *statusp = RCU_KTHREAD_RUNNING; + per_cpu(rcu_cpu_kthread_loops, cpu)++; local_irq_save(flags); work = *workp; *workp = 0; diff --git a/kernel/rcutree_trace.c b/kernel/rcutree_trace.c index 564b8fe..9678cc3 100644 --- a/kernel/rcutree_trace.c +++ b/kernel/rcutree_trace.c @@ -48,6 +48,7 @@ DECLARE_PER_CPU(unsigned int, rcu_cpu_kthread_status); DECLARE_PER_CPU(unsigned int, rcu_cpu_kthread_cpu); +DECLARE_PER_CPU(unsigned int, rcu_cpu_kthread_loops); DECLARE_PER_CPU(char, rcu_cpu_has_work); static char convert_kthread_status(unsigned int kthread_status) @@ -75,7 +76,7 @@ static void print_one_rcu_data(struct seq_file *m, struct rcu_data *rdp) rdp->dynticks_fqs); #endif /* #ifdef CONFIG_NO_HZ */ seq_printf(m, " of=%lu ri=%lu", rdp->offline_fqs, rdp->resched_ipi); - seq_printf(m, " ql=%ld qs=%c%c%c%c kt=%d/%c/%d b=%ld", + seq_printf(m, " ql=%ld qs=%c%c%c%c kt=%d/%c/%d ktl=%x b=%ld", rdp->qlen, ".N"[rdp->nxttail[RCU_NEXT_READY_TAIL] != rdp->nxttail[RCU_NEXT_TAIL]], @@ -88,6 +89,7 @@ static void print_one_rcu_data(struct seq_file *m, struct rcu_data *rdp) convert_kthread_status(per_cpu(rcu_cpu_kthread_status, rdp->cpu)), per_cpu(rcu_cpu_kthread_cpu, rdp->cpu), + per_cpu(rcu_cpu_kthread_loops, rdp->cpu) & 0xffff, rdp->blimit); seq_printf(m, " ci=%lu co=%lu ca=%lu\n", rdp->n_cbs_invoked, rdp->n_cbs_orphaned, rdp->n_cbs_adopted); -- cgit v1.1 From fc2ecf7ec76c5ee150b83dcefc863fa03fd365fb Mon Sep 17 00:00:00 2001 From: Mathieu Desnoyers Date: Wed, 23 Feb 2011 09:42:14 -0800 Subject: rcu: Enable DEBUG_OBJECTS_RCU_HEAD from !PREEMPT The prohibition of DEBUG_OBJECTS_RCU_HEAD from !PREEMPT was due to the fixup actions. So just produce a warning from !PREEMPT. Signed-off-by: Mathieu Desnoyers Signed-off-by: Paul E. McKenney Reviewed-by: Josh Triplett --- kernel/rcupdate.c | 26 +++++++++++++++++++++----- 1 file changed, 21 insertions(+), 5 deletions(-) (limited to 'kernel') diff --git a/kernel/rcupdate.c b/kernel/rcupdate.c index f3240e9..b54d6d1 100644 --- a/kernel/rcupdate.c +++ b/kernel/rcupdate.c @@ -142,7 +142,14 @@ static int rcuhead_fixup_init(void *addr, enum debug_obj_state state) * Ensure that queued callbacks are all executed. * If we detect that we are nested in a RCU read-side critical * section, we should simply fail, otherwise we would deadlock. + * In !PREEMPT configurations, there is no way to tell if we are + * in a RCU read-side critical section or not, so we never + * attempt any fixup and just print a warning. */ +#ifndef CONFIG_PREEMPT + WARN_ON(1); + return 0; +#endif if (rcu_preempt_depth() != 0 || preempt_count() != 0 || irqs_disabled()) { WARN_ON(1); @@ -184,7 +191,14 @@ static int rcuhead_fixup_activate(void *addr, enum debug_obj_state state) * Ensure that queued callbacks are all executed. * If we detect that we are nested in a RCU read-side critical * section, we should simply fail, otherwise we would deadlock. + * In !PREEMPT configurations, there is no way to tell if we are + * in a RCU read-side critical section or not, so we never + * attempt any fixup and just print a warning. */ +#ifndef CONFIG_PREEMPT + WARN_ON(1); + return 0; +#endif if (rcu_preempt_depth() != 0 || preempt_count() != 0 || irqs_disabled()) { WARN_ON(1); @@ -214,12 +228,14 @@ static int rcuhead_fixup_free(void *addr, enum debug_obj_state state) * Ensure that queued callbacks are all executed. * If we detect that we are nested in a RCU read-side critical * section, we should simply fail, otherwise we would deadlock. - * Note that the machinery to reliably determine whether - * or not we are in an RCU read-side critical section - * exists only in the preemptible RCU implementations - * (TINY_PREEMPT_RCU and TREE_PREEMPT_RCU), which is why - * DEBUG_OBJECTS_RCU_HEAD is disallowed if !PREEMPT. + * In !PREEMPT configurations, there is no way to tell if we are + * in a RCU read-side critical section or not, so we never + * attempt any fixup and just print a warning. */ +#ifndef CONFIG_PREEMPT + WARN_ON(1); + return 0; +#endif if (rcu_preempt_depth() != 0 || preempt_count() != 0 || irqs_disabled()) { WARN_ON(1); -- cgit v1.1 From 561190e3b3db372403fb6a327b0121b4cae1b87e Mon Sep 17 00:00:00 2001 From: "Paul E. McKenney" Date: Wed, 30 Mar 2011 09:10:44 -0700 Subject: rcu: mark rcutorture boosting callback as being on-stack The CONFIG_DEBUG_OBJECTS_RCU_HEAD facility requires that on-stack RCU callbacks be flagged explicitly to debug-objects using the init_rcu_head_on_stack() and destroy_rcu_head_on_stack() functions. This commit applies those functions to the rcutorture code that tests RCU priority boosting. Signed-off-by: Paul E. McKenney Signed-off-by: Paul E. McKenney Reviewed-by: Josh Triplett --- kernel/rcutorture.c | 2 ++ 1 file changed, 2 insertions(+) (limited to 'kernel') diff --git a/kernel/rcutorture.c b/kernel/rcutorture.c index c2f58ec..2e138db 100644 --- a/kernel/rcutorture.c +++ b/kernel/rcutorture.c @@ -749,6 +749,7 @@ static int rcu_torture_boost(void *arg) n_rcu_torture_boost_rterror++; } + init_rcu_head_on_stack(&rbi.rcu); /* Each pass through the following loop does one boost-test cycle. */ do { /* Wait for the next test interval. */ @@ -808,6 +809,7 @@ checkwait: rcu_stutter_wait("rcu_torture_boost"); /* Clean up and exit. */ VERBOSE_PRINTK_STRING("rcu_torture_boost task stopping"); + destroy_rcu_head_on_stack(&rbi.rcu); rcutorture_shutdown_absorb("rcu_torture_boost"); while (!kthread_should_stop() || rbi.inflight) schedule_timeout_uninterruptible(1); -- cgit v1.1 From 108aae22339f445c134aeb48eca25df1014ab08d Mon Sep 17 00:00:00 2001 From: "Paul E. McKenney" Date: Wed, 23 Feb 2011 09:56:00 -0800 Subject: rcu: Use WARN_ON_ONCE for DEBUG_OBJECTS_RCU_HEAD warnings Avoid additional multiple-warning confusion in memory-corruption scenarios. Signed-off-by: Paul E. McKenney Reviewed-by: Josh Triplett --- kernel/rcupdate.c | 12 ++++++------ 1 file changed, 6 insertions(+), 6 deletions(-) (limited to 'kernel') diff --git a/kernel/rcupdate.c b/kernel/rcupdate.c index b54d6d1..7784bd2 100644 --- a/kernel/rcupdate.c +++ b/kernel/rcupdate.c @@ -147,12 +147,12 @@ static int rcuhead_fixup_init(void *addr, enum debug_obj_state state) * attempt any fixup and just print a warning. */ #ifndef CONFIG_PREEMPT - WARN_ON(1); + WARN_ON_ONCE(1); return 0; #endif if (rcu_preempt_depth() != 0 || preempt_count() != 0 || irqs_disabled()) { - WARN_ON(1); + WARN_ON_ONCE(1); return 0; } rcu_barrier(); @@ -196,12 +196,12 @@ static int rcuhead_fixup_activate(void *addr, enum debug_obj_state state) * attempt any fixup and just print a warning. */ #ifndef CONFIG_PREEMPT - WARN_ON(1); + WARN_ON_ONCE(1); return 0; #endif if (rcu_preempt_depth() != 0 || preempt_count() != 0 || irqs_disabled()) { - WARN_ON(1); + WARN_ON_ONCE(1); return 0; } rcu_barrier(); @@ -233,12 +233,12 @@ static int rcuhead_fixup_free(void *addr, enum debug_obj_state state) * attempt any fixup and just print a warning. */ #ifndef CONFIG_PREEMPT - WARN_ON(1); + WARN_ON_ONCE(1); return 0; #endif if (rcu_preempt_depth() != 0 || preempt_count() != 0 || irqs_disabled()) { - WARN_ON(1); + WARN_ON_ONCE(1); return 0; } rcu_barrier(); -- cgit v1.1 From f0a07aeaf8935b7e9ef8032ce6546169f143951c Mon Sep 17 00:00:00 2001 From: "Paul E. McKenney" Date: Wed, 23 Feb 2011 11:10:52 -0800 Subject: rcu: Switch to this_cpu() primitives This removes a couple of lines from invoke_rcu_cpu_kthread(), improving readability. Reported-by: Christoph Lameter Signed-off-by: Paul E. McKenney Signed-off-by: Paul E. McKenney Reviewed-by: Josh Triplett --- kernel/rcutree.c | 10 +++------- 1 file changed, 3 insertions(+), 7 deletions(-) (limited to 'kernel') diff --git a/kernel/rcutree.c b/kernel/rcutree.c index 575d641..27304bc 100644 --- a/kernel/rcutree.c +++ b/kernel/rcutree.c @@ -1480,18 +1480,14 @@ static void rcu_process_callbacks(void) static void invoke_rcu_cpu_kthread(void) { unsigned long flags; - wait_queue_head_t *q; - int cpu; local_irq_save(flags); - cpu = smp_processor_id(); - per_cpu(rcu_cpu_has_work, cpu) = 1; - if (per_cpu(rcu_cpu_kthread_task, cpu) == NULL) { + __this_cpu_write(rcu_cpu_has_work, 1); + if (__this_cpu_read(rcu_cpu_kthread_task) == NULL) { local_irq_restore(flags); return; } - q = &per_cpu(rcu_cpu_wq, cpu); - wake_up(q); + wake_up(&__get_cpu_var(rcu_cpu_wq)); local_irq_restore(flags); } -- cgit v1.1 From ddeb75814f09205df795121d9e373e82de7f2aca Mon Sep 17 00:00:00 2001 From: "Paul E. McKenney" Date: Wed, 23 Feb 2011 17:03:06 -0800 Subject: rcu: code cleanups in TINY_RCU priority boosting. Extraneous semicolon, bad comment, and fold INIT_LIST_HEAD() into list_del() to get list_del_init(). Signed-off-by: Paul E. McKenney Signed-off-by: Paul E. McKenney Reviewed-by: Josh Triplett --- kernel/rcutiny_plugin.h | 7 +++---- 1 file changed, 3 insertions(+), 4 deletions(-) (limited to 'kernel') diff --git a/kernel/rcutiny_plugin.h b/kernel/rcutiny_plugin.h index 3cb8e36..0bc9f73 100644 --- a/kernel/rcutiny_plugin.h +++ b/kernel/rcutiny_plugin.h @@ -339,7 +339,7 @@ static void rcu_initiate_expedited_boost(void) raw_local_irq_restore(flags); } -#define RCU_BOOST_DELAY_JIFFIES DIV_ROUND_UP(CONFIG_RCU_BOOST_DELAY * HZ, 1000); +#define RCU_BOOST_DELAY_JIFFIES DIV_ROUND_UP(CONFIG_RCU_BOOST_DELAY * HZ, 1000) /* * Do priority-boost accounting for the start of a new grace period. @@ -418,7 +418,7 @@ static void rcu_preempt_cpu_qs(void) if (!rcu_preempt_gp_in_progress()) return; /* - * Check up on boosting. If there are no readers blocking the + * Check up on boosting. If there are readers blocking the * current grace period, leave. */ if (rcu_initiate_boost()) @@ -578,7 +578,7 @@ static void rcu_read_unlock_special(struct task_struct *t) empty = !rcu_preempt_blocked_readers_cgp(); empty_exp = rcu_preempt_ctrlblk.exp_tasks == NULL; np = rcu_next_node_entry(t); - list_del(&t->rcu_node_entry); + list_del_init(&t->rcu_node_entry); if (&t->rcu_node_entry == rcu_preempt_ctrlblk.gp_tasks) rcu_preempt_ctrlblk.gp_tasks = np; if (&t->rcu_node_entry == rcu_preempt_ctrlblk.exp_tasks) @@ -587,7 +587,6 @@ static void rcu_read_unlock_special(struct task_struct *t) if (&t->rcu_node_entry == rcu_preempt_ctrlblk.boost_tasks) rcu_preempt_ctrlblk.boost_tasks = np; #endif /* #ifdef CONFIG_RCU_BOOST */ - INIT_LIST_HEAD(&t->rcu_node_entry); /* * If this was the last task on the current list, and if -- cgit v1.1 From 203373c81b83e98da82836c4b8b5dd1e6fc9011f Mon Sep 17 00:00:00 2001 From: "Paul E. McKenney" Date: Thu, 24 Feb 2011 15:25:21 -0800 Subject: rcu: remove useless ->boosted_this_gp field The ->boosted_this_gp field is a holdover from an earlier design that was to carry out multiple boost operations in parallel. It is not required by the current design, which boosts one task at a time. Signed-off-by: Paul E. McKenney Signed-off-by: Paul E. McKenney --- kernel/rcutiny_plugin.h | 35 ++++------------------------------- 1 file changed, 4 insertions(+), 31 deletions(-) (limited to 'kernel') diff --git a/kernel/rcutiny_plugin.h b/kernel/rcutiny_plugin.h index 0bc9f73..2b8d529 100644 --- a/kernel/rcutiny_plugin.h +++ b/kernel/rcutiny_plugin.h @@ -100,7 +100,6 @@ struct rcu_preempt_ctrlblk { u8 completed; /* Last grace period completed. */ /* If all three are equal, RCU is idle. */ #ifdef CONFIG_RCU_BOOST - s8 boosted_this_gp; /* Has boosting already happened? */ unsigned long boost_time; /* When to start boosting (jiffies) */ #endif /* #ifdef CONFIG_RCU_BOOST */ #ifdef CONFIG_RCU_TRACE @@ -112,7 +111,6 @@ struct rcu_preempt_ctrlblk { unsigned long n_normal_balk_blkd_tasks; unsigned long n_normal_balk_gp_tasks; unsigned long n_normal_balk_boost_tasks; - unsigned long n_normal_balk_boosted; unsigned long n_normal_balk_notyet; unsigned long n_normal_balk_nos; unsigned long n_exp_balk_blkd_tasks; @@ -219,36 +217,19 @@ static void show_tiny_preempt_stats(struct seq_file *m) "N."[!rcu_preempt_ctrlblk.gp_tasks], "E."[!rcu_preempt_ctrlblk.exp_tasks]); #ifdef CONFIG_RCU_BOOST - seq_printf(m, " ttb=%c btg=", - "B."[!rcu_preempt_ctrlblk.boost_tasks]); - switch (rcu_preempt_ctrlblk.boosted_this_gp) { - case -1: - seq_puts(m, "exp"); - break; - case 0: - seq_puts(m, "no"); - break; - case 1: - seq_puts(m, "begun"); - break; - case 2: - seq_puts(m, "done"); - break; - default: - seq_printf(m, "?%d?", rcu_preempt_ctrlblk.boosted_this_gp); - } - seq_printf(m, " ntb=%lu neb=%lu nnb=%lu j=%04x bt=%04x\n", + seq_printf(m, "%sttb=%c ntb=%lu neb=%lu nnb=%lu j=%04x bt=%04x\n", + " ", + "B."[!rcu_preempt_ctrlblk.boost_tasks], rcu_preempt_ctrlblk.n_tasks_boosted, rcu_preempt_ctrlblk.n_exp_boosts, rcu_preempt_ctrlblk.n_normal_boosts, (int)(jiffies & 0xffff), (int)(rcu_preempt_ctrlblk.boost_time & 0xffff)); - seq_printf(m, " %s: nt=%lu gt=%lu bt=%lu b=%lu ny=%lu nos=%lu\n", + seq_printf(m, " %s: nt=%lu gt=%lu bt=%lu ny=%lu nos=%lu\n", "normal balk", rcu_preempt_ctrlblk.n_normal_balk_blkd_tasks, rcu_preempt_ctrlblk.n_normal_balk_gp_tasks, rcu_preempt_ctrlblk.n_normal_balk_boost_tasks, - rcu_preempt_ctrlblk.n_normal_balk_boosted, rcu_preempt_ctrlblk.n_normal_balk_notyet, rcu_preempt_ctrlblk.n_normal_balk_nos); seq_printf(m, " exp balk: bt=%lu nos=%lu\n", @@ -277,7 +258,6 @@ static int rcu_boost(void) if (rcu_preempt_ctrlblk.boost_tasks == NULL) return 0; /* Nothing to boost. */ raw_local_irq_save(flags); - rcu_preempt_ctrlblk.boosted_this_gp++; t = container_of(rcu_preempt_ctrlblk.boost_tasks, struct task_struct, rcu_node_entry); np = rcu_next_node_entry(t); @@ -287,7 +267,6 @@ static int rcu_boost(void) raw_local_irq_restore(flags); rt_mutex_lock(&mtx); RCU_TRACE(rcu_preempt_ctrlblk.n_tasks_boosted++); - rcu_preempt_ctrlblk.boosted_this_gp++; rt_mutex_unlock(&mtx); return rcu_preempt_ctrlblk.boost_tasks != NULL; } @@ -310,7 +289,6 @@ static int rcu_initiate_boost(void) } if (rcu_preempt_ctrlblk.gp_tasks != NULL && rcu_preempt_ctrlblk.boost_tasks == NULL && - rcu_preempt_ctrlblk.boosted_this_gp == 0 && ULONG_CMP_GE(jiffies, rcu_preempt_ctrlblk.boost_time)) { rcu_preempt_ctrlblk.boost_tasks = rcu_preempt_ctrlblk.gp_tasks; invoke_rcu_kthread(); @@ -331,7 +309,6 @@ static void rcu_initiate_expedited_boost(void) if (!list_empty(&rcu_preempt_ctrlblk.blkd_tasks)) { rcu_preempt_ctrlblk.boost_tasks = rcu_preempt_ctrlblk.blkd_tasks.next; - rcu_preempt_ctrlblk.boosted_this_gp = -1; invoke_rcu_kthread(); RCU_TRACE(rcu_preempt_ctrlblk.n_exp_boosts++); } else @@ -347,8 +324,6 @@ static void rcu_initiate_expedited_boost(void) static void rcu_preempt_boost_start_gp(void) { rcu_preempt_ctrlblk.boost_time = jiffies + RCU_BOOST_DELAY_JIFFIES; - if (rcu_preempt_ctrlblk.boosted_this_gp > 0) - rcu_preempt_ctrlblk.boosted_this_gp = 0; } #else /* #ifdef CONFIG_RCU_BOOST */ @@ -934,8 +909,6 @@ static void rcu_initiate_boost_trace(void) rcu_preempt_ctrlblk.n_normal_balk_gp_tasks++; else if (rcu_preempt_ctrlblk.boost_tasks != NULL) rcu_preempt_ctrlblk.n_normal_balk_boost_tasks++; - else if (rcu_preempt_ctrlblk.boosted_this_gp != 0) - rcu_preempt_ctrlblk.n_normal_balk_boosted++; else if (!ULONG_CMP_GE(jiffies, rcu_preempt_ctrlblk.boost_time)) rcu_preempt_ctrlblk.n_normal_balk_notyet++; else -- cgit v1.1 From 7e8b4c72344e0d904b0e3fa9fd2eb116f04b3d41 Mon Sep 17 00:00:00 2001 From: "Paul E. McKenney" Date: Thu, 24 Feb 2011 19:26:21 -0800 Subject: rcu: Converge TINY_RCU expedited and normal boosting This applies a trick from TREE_RCU boosting to TINY_RCU, eliminating code and adding comments. The key point is that it is possible for the booster thread itself to work out whether there is a normal or expedited boost required based solely on local information. There is therefore no need for boost initiation to know or care what type of boosting is required. In addition, when boosting is complete for a given grace period, then by definition there cannot be any more boosting for that grace period. This allows eliminating yet more state and statistics. Signed-off-by: Paul E. McKenney Signed-off-by: Paul E. McKenney Reviewed-by: Josh Triplett --- kernel/rcutiny_plugin.h | 163 ++++++++++++++++++++++++++---------------------- 1 file changed, 89 insertions(+), 74 deletions(-) (limited to 'kernel') diff --git a/kernel/rcutiny_plugin.h b/kernel/rcutiny_plugin.h index 2b8d529..f259c67 100644 --- a/kernel/rcutiny_plugin.h +++ b/kernel/rcutiny_plugin.h @@ -106,15 +106,22 @@ struct rcu_preempt_ctrlblk { unsigned long n_grace_periods; #ifdef CONFIG_RCU_BOOST unsigned long n_tasks_boosted; + /* Total number of tasks boosted. */ unsigned long n_exp_boosts; + /* Number of tasks boosted for expedited GP. */ unsigned long n_normal_boosts; - unsigned long n_normal_balk_blkd_tasks; - unsigned long n_normal_balk_gp_tasks; - unsigned long n_normal_balk_boost_tasks; - unsigned long n_normal_balk_notyet; - unsigned long n_normal_balk_nos; - unsigned long n_exp_balk_blkd_tasks; - unsigned long n_exp_balk_nos; + /* Number of tasks boosted for normal GP. */ + unsigned long n_balk_blkd_tasks; + /* Refused to boost: no blocked tasks. */ + unsigned long n_balk_exp_gp_tasks; + /* Refused to boost: nothing blocking GP. */ + unsigned long n_balk_boost_tasks; + /* Refused to boost: already boosting. */ + unsigned long n_balk_notyet; + /* Refused to boost: not yet time. */ + unsigned long n_balk_nos; + /* Refused to boost: not sure why, though. */ + /* This can happen due to race conditions. */ #endif /* #ifdef CONFIG_RCU_BOOST */ #endif /* #ifdef CONFIG_RCU_TRACE */ }; @@ -199,7 +206,6 @@ static struct list_head *rcu_next_node_entry(struct task_struct *t) #ifdef CONFIG_RCU_BOOST static void rcu_initiate_boost_trace(void); -static void rcu_initiate_exp_boost_trace(void); #endif /* #ifdef CONFIG_RCU_BOOST */ /* @@ -225,16 +231,13 @@ static void show_tiny_preempt_stats(struct seq_file *m) rcu_preempt_ctrlblk.n_normal_boosts, (int)(jiffies & 0xffff), (int)(rcu_preempt_ctrlblk.boost_time & 0xffff)); - seq_printf(m, " %s: nt=%lu gt=%lu bt=%lu ny=%lu nos=%lu\n", - "normal balk", - rcu_preempt_ctrlblk.n_normal_balk_blkd_tasks, - rcu_preempt_ctrlblk.n_normal_balk_gp_tasks, - rcu_preempt_ctrlblk.n_normal_balk_boost_tasks, - rcu_preempt_ctrlblk.n_normal_balk_notyet, - rcu_preempt_ctrlblk.n_normal_balk_nos); - seq_printf(m, " exp balk: bt=%lu nos=%lu\n", - rcu_preempt_ctrlblk.n_exp_balk_blkd_tasks, - rcu_preempt_ctrlblk.n_exp_balk_nos); + seq_printf(m, "%s: nt=%lu egt=%lu bt=%lu ny=%lu nos=%lu\n", + " balk", + rcu_preempt_ctrlblk.n_balk_blkd_tasks, + rcu_preempt_ctrlblk.n_balk_exp_gp_tasks, + rcu_preempt_ctrlblk.n_balk_boost_tasks, + rcu_preempt_ctrlblk.n_balk_notyet, + rcu_preempt_ctrlblk.n_balk_nos); #endif /* #ifdef CONFIG_RCU_BOOST */ } @@ -252,23 +255,59 @@ static int rcu_boost(void) { unsigned long flags; struct rt_mutex mtx; - struct list_head *np; struct task_struct *t; + struct list_head *tb; - if (rcu_preempt_ctrlblk.boost_tasks == NULL) + if (rcu_preempt_ctrlblk.boost_tasks == NULL && + rcu_preempt_ctrlblk.exp_tasks == NULL) return 0; /* Nothing to boost. */ + raw_local_irq_save(flags); - t = container_of(rcu_preempt_ctrlblk.boost_tasks, struct task_struct, - rcu_node_entry); - np = rcu_next_node_entry(t); + + /* + * Recheck with irqs disabled: all tasks in need of boosting + * might exit their RCU read-side critical sections on their own + * if we are preempted just before disabling irqs. + */ + if (rcu_preempt_ctrlblk.boost_tasks == NULL && + rcu_preempt_ctrlblk.exp_tasks == NULL) { + raw_local_irq_restore(flags); + return 0; + } + + /* + * Preferentially boost tasks blocking expedited grace periods. + * This cannot starve the normal grace periods because a second + * expedited grace period must boost all blocked tasks, including + * those blocking the pre-existing normal grace period. + */ + if (rcu_preempt_ctrlblk.exp_tasks != NULL) { + tb = rcu_preempt_ctrlblk.exp_tasks; + RCU_TRACE(rcu_preempt_ctrlblk.n_exp_boosts++); + } else { + tb = rcu_preempt_ctrlblk.boost_tasks; + RCU_TRACE(rcu_preempt_ctrlblk.n_normal_boosts++); + } + RCU_TRACE(rcu_preempt_ctrlblk.n_tasks_boosted++); + + /* + * We boost task t by manufacturing an rt_mutex that appears to + * be held by task t. We leave a pointer to that rt_mutex where + * task t can find it, and task t will release the mutex when it + * exits its outermost RCU read-side critical section. Then + * simply acquiring this artificial rt_mutex will boost task + * t's priority. (Thanks to tglx for suggesting this approach!) + */ + t = container_of(tb, struct task_struct, rcu_node_entry); rt_mutex_init_proxy_locked(&mtx, t); t->rcu_boost_mutex = &mtx; t->rcu_read_unlock_special |= RCU_READ_UNLOCK_BOOSTED; raw_local_irq_restore(flags); rt_mutex_lock(&mtx); - RCU_TRACE(rcu_preempt_ctrlblk.n_tasks_boosted++); - rt_mutex_unlock(&mtx); - return rcu_preempt_ctrlblk.boost_tasks != NULL; + rt_mutex_unlock(&mtx); /* Keep lockdep happy. */ + + return rcu_preempt_ctrlblk.boost_tasks != NULL || + rcu_preempt_ctrlblk.exp_tasks != NULL; } /* @@ -283,39 +322,24 @@ static int rcu_boost(void) */ static int rcu_initiate_boost(void) { - if (!rcu_preempt_blocked_readers_cgp()) { - RCU_TRACE(rcu_preempt_ctrlblk.n_normal_balk_blkd_tasks++); + if (!rcu_preempt_blocked_readers_cgp() && + rcu_preempt_ctrlblk.exp_tasks == NULL) { + RCU_TRACE(rcu_preempt_ctrlblk.n_balk_exp_gp_tasks++); return 0; } - if (rcu_preempt_ctrlblk.gp_tasks != NULL && - rcu_preempt_ctrlblk.boost_tasks == NULL && - ULONG_CMP_GE(jiffies, rcu_preempt_ctrlblk.boost_time)) { - rcu_preempt_ctrlblk.boost_tasks = rcu_preempt_ctrlblk.gp_tasks; + if (rcu_preempt_ctrlblk.exp_tasks != NULL || + (rcu_preempt_ctrlblk.gp_tasks != NULL && + rcu_preempt_ctrlblk.boost_tasks == NULL && + ULONG_CMP_GE(jiffies, rcu_preempt_ctrlblk.boost_time))) { + if (rcu_preempt_ctrlblk.exp_tasks == NULL) + rcu_preempt_ctrlblk.boost_tasks = + rcu_preempt_ctrlblk.gp_tasks; invoke_rcu_kthread(); - RCU_TRACE(rcu_preempt_ctrlblk.n_normal_boosts++); } else RCU_TRACE(rcu_initiate_boost_trace()); return 1; } -/* - * Initiate boosting for an expedited grace period. - */ -static void rcu_initiate_expedited_boost(void) -{ - unsigned long flags; - - raw_local_irq_save(flags); - if (!list_empty(&rcu_preempt_ctrlblk.blkd_tasks)) { - rcu_preempt_ctrlblk.boost_tasks = - rcu_preempt_ctrlblk.blkd_tasks.next; - invoke_rcu_kthread(); - RCU_TRACE(rcu_preempt_ctrlblk.n_exp_boosts++); - } else - RCU_TRACE(rcu_initiate_exp_boost_trace()); - raw_local_irq_restore(flags); -} - #define RCU_BOOST_DELAY_JIFFIES DIV_ROUND_UP(CONFIG_RCU_BOOST_DELAY * HZ, 1000) /* @@ -347,13 +371,6 @@ static int rcu_initiate_boost(void) } /* - * If there is no RCU priority boosting, we don't initiate expedited boosting. - */ -static void rcu_initiate_expedited_boost(void) -{ -} - -/* * If there is no RCU priority boosting, nothing to do at grace-period start. */ static void rcu_preempt_boost_start_gp(void) @@ -786,13 +803,16 @@ void synchronize_rcu_expedited(void) rpcp->exp_tasks = rpcp->blkd_tasks.next; if (rpcp->exp_tasks == &rpcp->blkd_tasks) rpcp->exp_tasks = NULL; - local_irq_restore(flags); /* Wait for tail of ->blkd_tasks list to drain. */ - if (rcu_preempted_readers_exp()) - rcu_initiate_expedited_boost(); + if (!rcu_preempted_readers_exp()) + local_irq_restore(flags); + else { + rcu_initiate_boost(); + local_irq_restore(flags); wait_event(sync_rcu_preempt_exp_wq, !rcu_preempted_readers_exp()); + } /* Clean up and exit. */ barrier(); /* ensure expedited GP seen before counter increment. */ @@ -905,22 +925,17 @@ void __init rcu_scheduler_starting(void) static void rcu_initiate_boost_trace(void) { - if (rcu_preempt_ctrlblk.gp_tasks == NULL) - rcu_preempt_ctrlblk.n_normal_balk_gp_tasks++; + if (list_empty(&rcu_preempt_ctrlblk.blkd_tasks)) + rcu_preempt_ctrlblk.n_balk_blkd_tasks++; + else if (rcu_preempt_ctrlblk.gp_tasks == NULL && + rcu_preempt_ctrlblk.exp_tasks == NULL) + rcu_preempt_ctrlblk.n_balk_exp_gp_tasks++; else if (rcu_preempt_ctrlblk.boost_tasks != NULL) - rcu_preempt_ctrlblk.n_normal_balk_boost_tasks++; + rcu_preempt_ctrlblk.n_balk_boost_tasks++; else if (!ULONG_CMP_GE(jiffies, rcu_preempt_ctrlblk.boost_time)) - rcu_preempt_ctrlblk.n_normal_balk_notyet++; - else - rcu_preempt_ctrlblk.n_normal_balk_nos++; -} - -static void rcu_initiate_exp_boost_trace(void) -{ - if (list_empty(&rcu_preempt_ctrlblk.blkd_tasks)) - rcu_preempt_ctrlblk.n_exp_balk_blkd_tasks++; + rcu_preempt_ctrlblk.n_balk_notyet++; else - rcu_preempt_ctrlblk.n_exp_balk_nos++; + rcu_preempt_ctrlblk.n_balk_nos++; } #endif /* #ifdef CONFIG_RCU_BOOST */ -- cgit v1.1 From 13491a0ee1ef862b6c842132b6eb9c5e721af5ad Mon Sep 17 00:00:00 2001 From: Lai Jiangshan Date: Fri, 25 Feb 2011 11:37:59 -0800 Subject: rcu: call __rcu_read_unlock() in exit_rcu for tree RCU Using __rcu_read_lock() in place of rcu_read_lock() leaves any debug state as it really should be, namely with the lock still held. Signed-off-by: Lai Jiangshan Signed-off-by: Paul E. McKenney Reviewed-by: Josh Triplett --- kernel/rcutree_plugin.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'kernel') diff --git a/kernel/rcutree_plugin.h b/kernel/rcutree_plugin.h index a21413d..11b27f3 100644 --- a/kernel/rcutree_plugin.h +++ b/kernel/rcutree_plugin.h @@ -858,7 +858,7 @@ void exit_rcu(void) if (t->rcu_read_lock_nesting == 0) return; t->rcu_read_lock_nesting = 1; - rcu_read_unlock(); + __rcu_read_unlock(); } #else /* #ifdef CONFIG_TREE_PREEMPT_RCU */ -- cgit v1.1 From 6cc68793e380bb51f447d8d02af873b7bc01f222 Mon Sep 17 00:00:00 2001 From: "Paul E. McKenney" Date: Wed, 2 Mar 2011 13:15:15 -0800 Subject: rcu: fix spelling The "preemptible" spelling is preferable. May as well fix it. Signed-off-by: Paul E. McKenney Reviewed-by: Josh Triplett --- kernel/rcutree.c | 10 ++++---- kernel/rcutree.h | 2 +- kernel/rcutree_plugin.h | 62 ++++++++++++++++++++++++------------------------- 3 files changed, 37 insertions(+), 37 deletions(-) (limited to 'kernel') diff --git a/kernel/rcutree.c b/kernel/rcutree.c index 27304bc..b579e4f 100644 --- a/kernel/rcutree.c +++ b/kernel/rcutree.c @@ -290,8 +290,8 @@ static int rcu_implicit_offline_qs(struct rcu_data *rdp) return 1; } - /* If preemptable RCU, no point in sending reschedule IPI. */ - if (rdp->preemptable) + /* If preemptible RCU, no point in sending reschedule IPI. */ + if (rdp->preemptible) return 0; /* The CPU is online, so send it a reschedule IPI. */ @@ -1982,7 +1982,7 @@ static int __rcu_pending(struct rcu_state *rsp, struct rcu_data *rdp) * or RCU-bh, force a local reschedule. */ rdp->n_rp_qs_pending++; - if (!rdp->preemptable && + if (!rdp->preemptible && ULONG_CMP_LT(ACCESS_ONCE(rsp->jiffies_force_qs) - 1, jiffies)) set_need_resched(); @@ -2159,7 +2159,7 @@ rcu_boot_init_percpu_data(int cpu, struct rcu_state *rsp) * that this CPU cannot possibly have any RCU callbacks in flight yet. */ static void __cpuinit -rcu_init_percpu_data(int cpu, struct rcu_state *rsp, int preemptable) +rcu_init_percpu_data(int cpu, struct rcu_state *rsp, int preemptible) { unsigned long flags; unsigned long mask; @@ -2171,7 +2171,7 @@ rcu_init_percpu_data(int cpu, struct rcu_state *rsp, int preemptable) rdp->passed_quiesc = 0; /* We could be racing with new GP, */ rdp->qs_pending = 1; /* so set up to respond to current GP. */ rdp->beenonline = 1; /* We have now been online. */ - rdp->preemptable = preemptable; + rdp->preemptible = preemptible; rdp->qlen_last_fqs_check = 0; rdp->n_force_qs_snap = rsp->n_force_qs; rdp->blimit = blimit; diff --git a/kernel/rcutree.h b/kernel/rcutree.h index 37502a2..a6a9717 100644 --- a/kernel/rcutree.h +++ b/kernel/rcutree.h @@ -239,7 +239,7 @@ struct rcu_data { bool passed_quiesc; /* User-mode/idle loop etc. */ bool qs_pending; /* Core waits for quiesc state. */ bool beenonline; /* CPU online at least once. */ - bool preemptable; /* Preemptable RCU? */ + bool preemptible; /* Preemptible RCU? */ struct rcu_node *mynode; /* This CPU's leaf of hierarchy */ unsigned long grpmask; /* Mask to apply to leaf qsmask. */ diff --git a/kernel/rcutree_plugin.h b/kernel/rcutree_plugin.h index 11b27f3..f629479 100644 --- a/kernel/rcutree_plugin.h +++ b/kernel/rcutree_plugin.h @@ -1,7 +1,7 @@ /* * Read-Copy Update mechanism for mutual exclusion (tree-based version) * Internal non-public definitions that provide either classic - * or preemptable semantics. + * or preemptible semantics. * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by @@ -75,7 +75,7 @@ static int rcu_preempted_readers_exp(struct rcu_node *rnp); */ static void __init rcu_bootup_announce(void) { - printk(KERN_INFO "Preemptable hierarchical RCU implementation.\n"); + printk(KERN_INFO "Preemptible hierarchical RCU implementation.\n"); rcu_bootup_announce_oddness(); } @@ -108,7 +108,7 @@ void rcu_force_quiescent_state(void) EXPORT_SYMBOL_GPL(rcu_force_quiescent_state); /* - * Record a preemptable-RCU quiescent state for the specified CPU. Note + * Record a preemptible-RCU quiescent state for the specified CPU. Note * that this just means that the task currently running on the CPU is * not in a quiescent state. There might be any number of tasks blocked * while in an RCU read-side critical section. @@ -207,7 +207,7 @@ static void rcu_preempt_note_context_switch(int cpu) } /* - * Tree-preemptable RCU implementation for rcu_read_lock(). + * Tree-preemptible RCU implementation for rcu_read_lock(). * Just increment ->rcu_read_lock_nesting, shared state will be updated * if we block. */ @@ -376,7 +376,7 @@ static void rcu_read_unlock_special(struct task_struct *t) } /* - * Tree-preemptable RCU implementation for rcu_read_unlock(). + * Tree-preemptible RCU implementation for rcu_read_unlock(). * Decrement ->rcu_read_lock_nesting. If the result is zero (outermost * rcu_read_unlock()) and ->rcu_read_unlock_special is non-zero, then * invoke rcu_read_unlock_special() to clean up after a context switch @@ -565,7 +565,7 @@ static int rcu_preempt_offline_tasks(struct rcu_state *rsp, } /* - * Do CPU-offline processing for preemptable RCU. + * Do CPU-offline processing for preemptible RCU. */ static void rcu_preempt_offline_cpu(int cpu) { @@ -594,7 +594,7 @@ static void rcu_preempt_check_callbacks(int cpu) } /* - * Process callbacks for preemptable RCU. + * Process callbacks for preemptible RCU. */ static void rcu_preempt_process_callbacks(void) { @@ -603,7 +603,7 @@ static void rcu_preempt_process_callbacks(void) } /* - * Queue a preemptable-RCU callback for invocation after a grace period. + * Queue a preemptible-RCU callback for invocation after a grace period. */ void call_rcu(struct rcu_head *head, void (*func)(struct rcu_head *rcu)) { @@ -795,7 +795,7 @@ mb_ret: EXPORT_SYMBOL_GPL(synchronize_rcu_expedited); /* - * Check to see if there is any immediate preemptable-RCU-related work + * Check to see if there is any immediate preemptible-RCU-related work * to be done. */ static int rcu_preempt_pending(int cpu) @@ -805,7 +805,7 @@ static int rcu_preempt_pending(int cpu) } /* - * Does preemptable RCU need the CPU to stay out of dynticks mode? + * Does preemptible RCU need the CPU to stay out of dynticks mode? */ static int rcu_preempt_needs_cpu(int cpu) { @@ -822,7 +822,7 @@ void rcu_barrier(void) EXPORT_SYMBOL_GPL(rcu_barrier); /* - * Initialize preemptable RCU's per-CPU data. + * Initialize preemptible RCU's per-CPU data. */ static void __cpuinit rcu_preempt_init_percpu_data(int cpu) { @@ -830,7 +830,7 @@ static void __cpuinit rcu_preempt_init_percpu_data(int cpu) } /* - * Move preemptable RCU's callbacks from dying CPU to other online CPU. + * Move preemptible RCU's callbacks from dying CPU to other online CPU. */ static void rcu_preempt_send_cbs_to_online(void) { @@ -838,7 +838,7 @@ static void rcu_preempt_send_cbs_to_online(void) } /* - * Initialize preemptable RCU's state structures. + * Initialize preemptible RCU's state structures. */ static void __init __rcu_init_preempt(void) { @@ -846,7 +846,7 @@ static void __init __rcu_init_preempt(void) } /* - * Check for a task exiting while in a preemptable-RCU read-side + * Check for a task exiting while in a preemptible-RCU read-side * critical section, clean up if so. No need to issue warnings, * as debug_check_no_locks_held() already does this if lockdep * is enabled. @@ -894,7 +894,7 @@ void rcu_force_quiescent_state(void) EXPORT_SYMBOL_GPL(rcu_force_quiescent_state); /* - * Because preemptable RCU does not exist, we never have to check for + * Because preemptible RCU does not exist, we never have to check for * CPUs being in quiescent states. */ static void rcu_preempt_note_context_switch(int cpu) @@ -902,7 +902,7 @@ static void rcu_preempt_note_context_switch(int cpu) } /* - * Because preemptable RCU does not exist, there are never any preempted + * Because preemptible RCU does not exist, there are never any preempted * RCU readers. */ static int rcu_preempt_blocked_readers_cgp(struct rcu_node *rnp) @@ -921,7 +921,7 @@ static void rcu_report_unblock_qs_rnp(struct rcu_node *rnp, unsigned long flags) #endif /* #ifdef CONFIG_HOTPLUG_CPU */ /* - * Because preemptable RCU does not exist, we never have to check for + * Because preemptible RCU does not exist, we never have to check for * tasks blocked within RCU read-side critical sections. */ static void rcu_print_detail_task_stall(struct rcu_state *rsp) @@ -929,7 +929,7 @@ static void rcu_print_detail_task_stall(struct rcu_state *rsp) } /* - * Because preemptable RCU does not exist, we never have to check for + * Because preemptible RCU does not exist, we never have to check for * tasks blocked within RCU read-side critical sections. */ static void rcu_print_task_stall(struct rcu_node *rnp) @@ -945,7 +945,7 @@ static void rcu_preempt_stall_reset(void) } /* - * Because there is no preemptable RCU, there can be no readers blocked, + * Because there is no preemptible RCU, there can be no readers blocked, * so there is no need to check for blocked tasks. So check only for * bogus qsmask values. */ @@ -957,7 +957,7 @@ static void rcu_preempt_check_blocked_tasks(struct rcu_node *rnp) #ifdef CONFIG_HOTPLUG_CPU /* - * Because preemptable RCU does not exist, it never needs to migrate + * Because preemptible RCU does not exist, it never needs to migrate * tasks that were blocked within RCU read-side critical sections, and * such non-existent tasks cannot possibly have been blocking the current * grace period. @@ -970,7 +970,7 @@ static int rcu_preempt_offline_tasks(struct rcu_state *rsp, } /* - * Because preemptable RCU does not exist, it never needs CPU-offline + * Because preemptible RCU does not exist, it never needs CPU-offline * processing. */ static void rcu_preempt_offline_cpu(int cpu) @@ -980,7 +980,7 @@ static void rcu_preempt_offline_cpu(int cpu) #endif /* #ifdef CONFIG_HOTPLUG_CPU */ /* - * Because preemptable RCU does not exist, it never has any callbacks + * Because preemptible RCU does not exist, it never has any callbacks * to check. */ static void rcu_preempt_check_callbacks(int cpu) @@ -988,7 +988,7 @@ static void rcu_preempt_check_callbacks(int cpu) } /* - * Because preemptable RCU does not exist, it never has any callbacks + * Because preemptible RCU does not exist, it never has any callbacks * to process. */ static void rcu_preempt_process_callbacks(void) @@ -997,7 +997,7 @@ static void rcu_preempt_process_callbacks(void) /* * Wait for an rcu-preempt grace period, but make it happen quickly. - * But because preemptable RCU does not exist, map to rcu-sched. + * But because preemptible RCU does not exist, map to rcu-sched. */ void synchronize_rcu_expedited(void) { @@ -1008,7 +1008,7 @@ EXPORT_SYMBOL_GPL(synchronize_rcu_expedited); #ifdef CONFIG_HOTPLUG_CPU /* - * Because preemptable RCU does not exist, there is never any need to + * Because preemptible RCU does not exist, there is never any need to * report on tasks preempted in RCU read-side critical sections during * expedited RCU grace periods. */ @@ -1020,7 +1020,7 @@ static void rcu_report_exp_rnp(struct rcu_state *rsp, struct rcu_node *rnp) #endif /* #ifdef CONFIG_HOTPLUG_CPU */ /* - * Because preemptable RCU does not exist, it never has any work to do. + * Because preemptible RCU does not exist, it never has any work to do. */ static int rcu_preempt_pending(int cpu) { @@ -1028,7 +1028,7 @@ static int rcu_preempt_pending(int cpu) } /* - * Because preemptable RCU does not exist, it never needs any CPU. + * Because preemptible RCU does not exist, it never needs any CPU. */ static int rcu_preempt_needs_cpu(int cpu) { @@ -1036,7 +1036,7 @@ static int rcu_preempt_needs_cpu(int cpu) } /* - * Because preemptable RCU does not exist, rcu_barrier() is just + * Because preemptible RCU does not exist, rcu_barrier() is just * another name for rcu_barrier_sched(). */ void rcu_barrier(void) @@ -1046,7 +1046,7 @@ void rcu_barrier(void) EXPORT_SYMBOL_GPL(rcu_barrier); /* - * Because preemptable RCU does not exist, there is no per-CPU + * Because preemptible RCU does not exist, there is no per-CPU * data to initialize. */ static void __cpuinit rcu_preempt_init_percpu_data(int cpu) @@ -1054,14 +1054,14 @@ static void __cpuinit rcu_preempt_init_percpu_data(int cpu) } /* - * Because there is no preemptable RCU, there are no callbacks to move. + * Because there is no preemptible RCU, there are no callbacks to move. */ static void rcu_preempt_send_cbs_to_online(void) { } /* - * Because preemptable RCU does not exist, it need not be initialized. + * Because preemptible RCU does not exist, it need not be initialized. */ static void __init __rcu_init_preempt(void) { -- cgit v1.1 From 9ab1544eb4196ca8d05c433b2eb56f74496b1ee3 Mon Sep 17 00:00:00 2001 From: Lai Jiangshan Date: Fri, 18 Mar 2011 11:15:47 +0800 Subject: rcu: introduce kfree_rcu() Many rcu callbacks functions just call kfree() on the base structure. These functions are trivial, but their size adds up, and furthermore when they are used in a kernel module, that module must invoke the high-latency rcu_barrier() function at module-unload time. The kfree_rcu() function introduced by this commit addresses this issue. Rather than encoding a function address in the embedded rcu_head structure, kfree_rcu() instead encodes the offset of the rcu_head structure within the base structure. Because the functions are not allowed in the low-order 4096 bytes of kernel virtual memory, offsets up to 4095 bytes can be accommodated. If the offset is larger than 4095 bytes, a compile-time error will be generated in __kfree_rcu(). If this error is triggered, you can either fall back to use of call_rcu() or rearrange the structure to position the rcu_head structure into the first 4096 bytes. Note that the allowable offset might decrease in the future, for example, to allow something like kmem_cache_free_rcu(). The new kfree_rcu() function can replace code as follows: call_rcu(&p->rcu, simple_kfree_callback); where "simple_kfree_callback()" might be defined as follows: void simple_kfree_callback(struct rcu_head *p) { struct foo *q = container_of(p, struct foo, rcu); kfree(q); } with the following: kfree_rcu(&p->rcu, rcu); Note that the "rcu" is the name of a field in the structure being freed. The reason for using this rather than passing in a pointer to the base structure is that the above approach allows better type checking. This commit is based on earlier work by Lai Jiangshan and Manfred Spraul: Lai's V1 patch: http://lkml.org/lkml/2008/9/18/1 Manfred's patch: http://lkml.org/lkml/2009/1/2/115 Signed-off-by: Lai Jiangshan Signed-off-by: Manfred Spraul Signed-off-by: Paul E. McKenney Reviewed-by: David Howells Reviewed-by: Josh Triplett --- kernel/rcutiny.c | 2 +- kernel/rcutree.c | 2 +- 2 files changed, 2 insertions(+), 2 deletions(-) (limited to 'kernel') diff --git a/kernel/rcutiny.c b/kernel/rcutiny.c index 0c343b9..4d60fbc 100644 --- a/kernel/rcutiny.c +++ b/kernel/rcutiny.c @@ -167,7 +167,7 @@ static void rcu_process_callbacks(struct rcu_ctrlblk *rcp) prefetch(next); debug_rcu_head_unqueue(list); local_bh_disable(); - list->func(list); + __rcu_reclaim(list); local_bh_enable(); list = next; RCU_TRACE(cb_count++); diff --git a/kernel/rcutree.c b/kernel/rcutree.c index b579e4f..2c07adb 100644 --- a/kernel/rcutree.c +++ b/kernel/rcutree.c @@ -1206,7 +1206,7 @@ static void rcu_do_batch(struct rcu_state *rsp, struct rcu_data *rdp) next = list->next; prefetch(next); debug_rcu_head_unqueue(list); - list->func(list); + __rcu_reclaim(list); list = next; if (++count >= rdp->blimit) break; -- cgit v1.1 From baa1ae0c9f1c618bc60706efa75fef3508bcee58 Mon Sep 17 00:00:00 2001 From: "Paul E. McKenney" Date: Sat, 26 Mar 2011 22:01:35 -0700 Subject: rcu: further lower priority in rcu_yield() Although rcu_yield() dropped from real-time to normal priority, there is always the possibility that the competing tasks have been niced. So nice to 19 in rcu_yield() to help ensure that other tasks have a better chance of running. Signed-off-by: Paul E. McKenney Signed-off-by: Paul E. McKenney Reviewed-by: Josh Triplett --- kernel/rcutree.c | 1 + 1 file changed, 1 insertion(+) (limited to 'kernel') diff --git a/kernel/rcutree.c b/kernel/rcutree.c index 2c07adb..fe85600 100644 --- a/kernel/rcutree.c +++ b/kernel/rcutree.c @@ -1561,6 +1561,7 @@ static void rcu_yield(void (*f)(unsigned long), unsigned long arg) mod_timer(&yield_timer, jiffies + 2); sp.sched_priority = 0; sched_setscheduler_nocheck(current, SCHED_NORMAL, &sp); + set_user_nice(current, 19); schedule(); sp.sched_priority = RCU_KTHREAD_PRIO; sched_setscheduler_nocheck(current, SCHED_FIFO, &sp); -- cgit v1.1 From 2655d57ef35aa327a2e58a1c5dc7b65c65003f4e Mon Sep 17 00:00:00 2001 From: "Paul E. McKenney" Date: Thu, 7 Apr 2011 22:47:23 -0700 Subject: rcu: prevent call_rcu() from diving into rcu core if irqs disabled This commit marks a first step towards making call_rcu() have real-time behavior. If irqs are disabled, don't dive into the RCU core. Later on, this new early exit will wake up the per-CPU kthread, which first must be modified to handle the cases involving callback storms. Signed-off-by: Paul E. McKenney Reviewed-by: Josh Triplett --- kernel/rcutree.c | 9 ++++++++- 1 file changed, 8 insertions(+), 1 deletion(-) (limited to 'kernel') diff --git a/kernel/rcutree.c b/kernel/rcutree.c index fe85600..78923a5 100644 --- a/kernel/rcutree.c +++ b/kernel/rcutree.c @@ -1839,6 +1839,13 @@ __call_rcu(struct rcu_head *head, void (*func)(struct rcu_head *rcu), /* Add the callback to our list. */ *rdp->nxttail[RCU_NEXT_TAIL] = head; rdp->nxttail[RCU_NEXT_TAIL] = &head->next; + rdp->qlen++; + + /* If interrupts were disabled, don't dive into RCU core. */ + if (irqs_disabled_flags(flags)) { + local_irq_restore(flags); + return; + } /* * Force the grace period if too many callbacks or too long waiting. @@ -1847,7 +1854,7 @@ __call_rcu(struct rcu_head *head, void (*func)(struct rcu_head *rcu), * invoking force_quiescent_state() if the newly enqueued callback * is the only one waiting for a grace period to complete. */ - if (unlikely(++rdp->qlen > rdp->qlen_last_fqs_check + qhimark)) { + if (unlikely(rdp->qlen > rdp->qlen_last_fqs_check + qhimark)) { /* Are we ignoring a completed grace period? */ rcu_process_gp_end(rsp, rdp); -- cgit v1.1 From b554d7de8d112fca4188da3bf0d7f8b56f42fb95 Mon Sep 17 00:00:00 2001 From: Eric Dumazet Date: Thu, 28 Apr 2011 07:23:45 +0200 Subject: rcu: optimize rcutiny rcu_sched_qs() currently calls local_irq_save()/local_irq_restore() up to three times. Remove irq masking from rcu_qsctr_help() / invoke_rcu_kthread() and do it once in rcu_sched_qs() / rcu_bh_qs() This generates smaller code as well. text data bss dec hex filename 2314 156 24 2494 9be kernel/rcutiny.old.o 2250 156 24 2430 97e kernel/rcutiny.new.o Fix an outdated comment for rcu_qsctr_help() Move invoke_rcu_kthread() definition before its use. Signed-off-by: Eric Dumazet Signed-off-by: Paul E. McKenney Reviewed-by: Josh Triplett --- kernel/rcutiny.c | 43 +++++++++++++++++++++---------------------- 1 file changed, 21 insertions(+), 22 deletions(-) (limited to 'kernel') diff --git a/kernel/rcutiny.c b/kernel/rcutiny.c index 4d60fbc..421abfd 100644 --- a/kernel/rcutiny.c +++ b/kernel/rcutiny.c @@ -40,10 +40,10 @@ static struct task_struct *rcu_kthread_task; static DECLARE_WAIT_QUEUE_HEAD(rcu_kthread_wq); static unsigned long have_rcu_kthread_work; -static void invoke_rcu_kthread(void); /* Forward declarations for rcutiny_plugin.h. */ struct rcu_ctrlblk; +static void invoke_rcu_kthread(void); static void rcu_process_callbacks(struct rcu_ctrlblk *rcp); static int rcu_kthread(void *arg); static void __call_rcu(struct rcu_head *head, @@ -79,36 +79,45 @@ void rcu_exit_nohz(void) #endif /* #ifdef CONFIG_NO_HZ */ /* - * Helper function for rcu_qsctr_inc() and rcu_bh_qsctr_inc(). - * Also disable irqs to avoid confusion due to interrupt handlers + * Helper function for rcu_sched_qs() and rcu_bh_qs(). + * Also irqs are disabled to avoid confusion due to interrupt handlers * invoking call_rcu(). */ static int rcu_qsctr_help(struct rcu_ctrlblk *rcp) { - unsigned long flags; - - local_irq_save(flags); if (rcp->rcucblist != NULL && rcp->donetail != rcp->curtail) { rcp->donetail = rcp->curtail; - local_irq_restore(flags); return 1; } - local_irq_restore(flags); return 0; } /* + * Wake up rcu_kthread() to process callbacks now eligible for invocation + * or to boost readers. + */ +static void invoke_rcu_kthread(void) +{ + have_rcu_kthread_work = 1; + wake_up(&rcu_kthread_wq); +} + +/* * Record an rcu quiescent state. And an rcu_bh quiescent state while we * are at it, given that any rcu quiescent state is also an rcu_bh * quiescent state. Use "+" instead of "||" to defeat short circuiting. */ void rcu_sched_qs(int cpu) { + unsigned long flags; + + local_irq_save(flags); if (rcu_qsctr_help(&rcu_sched_ctrlblk) + rcu_qsctr_help(&rcu_bh_ctrlblk)) invoke_rcu_kthread(); + local_irq_restore(flags); } /* @@ -116,8 +125,12 @@ void rcu_sched_qs(int cpu) */ void rcu_bh_qs(int cpu) { + unsigned long flags; + + local_irq_save(flags); if (rcu_qsctr_help(&rcu_bh_ctrlblk)) invoke_rcu_kthread(); + local_irq_restore(flags); } /* @@ -208,20 +221,6 @@ static int rcu_kthread(void *arg) } /* - * Wake up rcu_kthread() to process callbacks now eligible for invocation - * or to boost readers. - */ -static void invoke_rcu_kthread(void) -{ - unsigned long flags; - - local_irq_save(flags); - have_rcu_kthread_work = 1; - wake_up(&rcu_kthread_wq); - local_irq_restore(flags); -} - -/* * Wait for a grace period to elapse. But it is illegal to invoke * synchronize_sched() from within an RCU read-side critical section. * Therefore, any legal call to synchronize_sched() is a quiescent -- cgit v1.1 From bad6e1393cb505fe17747344a23666464daa3fa7 Mon Sep 17 00:00:00 2001 From: "Paul E. McKenney" Date: Mon, 2 May 2011 23:40:04 -0700 Subject: rcu: get rid of signed overflow in check_cpu_stall() Signed integer overflow is undefined by the C standard, so move calculations to unsigned. Signed-off-by: Paul E. McKenney --- kernel/rcutree.c | 13 ++++++++----- 1 file changed, 8 insertions(+), 5 deletions(-) (limited to 'kernel') diff --git a/kernel/rcutree.c b/kernel/rcutree.c index 78923a5..b2fe2a2 100644 --- a/kernel/rcutree.c +++ b/kernel/rcutree.c @@ -581,21 +581,24 @@ static void print_cpu_stall(struct rcu_state *rsp) static void check_cpu_stall(struct rcu_state *rsp, struct rcu_data *rdp) { - long delta; + unsigned long j; + unsigned long js; struct rcu_node *rnp; if (rcu_cpu_stall_suppress) return; - delta = jiffies - ACCESS_ONCE(rsp->jiffies_stall); + j = ACCESS_ONCE(jiffies); + js = ACCESS_ONCE(rsp->jiffies_stall); rnp = rdp->mynode; - if ((ACCESS_ONCE(rnp->qsmask) & rdp->grpmask) && delta >= 0) { + if ((ACCESS_ONCE(rnp->qsmask) & rdp->grpmask) && ULONG_CMP_GE(j, js)) { /* We haven't checked in, so go dump stack. */ print_cpu_stall(rsp); - } else if (rcu_gp_in_progress(rsp) && delta >= RCU_STALL_RAT_DELAY) { + } else if (rcu_gp_in_progress(rsp) && + ULONG_CMP_GE(j, js + RCU_STALL_RAT_DELAY)) { - /* They had two time units to dump stack, so complain. */ + /* They had a few time units to dump stack, so complain. */ print_other_cpu_stall(rsp); } } -- cgit v1.1 From 29ce831000081dd757d3116bf774aafffc4b6b20 Mon Sep 17 00:00:00 2001 From: Gleb Natapov Date: Wed, 4 May 2011 16:31:03 +0300 Subject: rcu: provide rcu_virt_note_context_switch() function. Provide rcu_virt_note_context_switch() for vitalization use to note quiescent state during guest entry. Signed-off-by: Gleb Natapov Signed-off-by: Paul E. McKenney --- kernel/rcutree.c | 1 + 1 file changed, 1 insertion(+) (limited to 'kernel') diff --git a/kernel/rcutree.c b/kernel/rcutree.c index b2fe2a2..54ff7eb 100644 --- a/kernel/rcutree.c +++ b/kernel/rcutree.c @@ -157,6 +157,7 @@ void rcu_note_context_switch(int cpu) rcu_sched_qs(cpu); rcu_preempt_note_context_switch(cpu); } +EXPORT_SYMBOL_GPL(rcu_note_context_switch); #ifdef CONFIG_NO_HZ DEFINE_PER_CPU(struct rcu_dynticks, rcu_dynticks) = { -- cgit v1.1 From 4934a4d3d3fa775601a9f1b35cc0e2aa93f81355 Mon Sep 17 00:00:00 2001 From: Rakib Mullick Date: Wed, 4 May 2011 22:53:46 +0600 Subject: sched: Wrap the 'cfs_rq->nr_spread_over' field with CONFIG_SCHED_DEBUG cfs_rq->nr_spread_over is only used when CONFIG_SCHED_DEBUG is set. So wrap it with CONFIG_SCHED_DEBUG. Signed-off-by: Rakib Mullick Cc: Peter Zijlstra Link: http://lkml.kernel.org/r/1304528026.15681.3.camel@localhost.localdomain Signed-off-by: Ingo Molnar --- kernel/sched.c | 2 ++ 1 file changed, 2 insertions(+) (limited to 'kernel') diff --git a/kernel/sched.c b/kernel/sched.c index f11a2a5..3d8a1b2 100644 --- a/kernel/sched.c +++ b/kernel/sched.c @@ -328,7 +328,9 @@ struct cfs_rq { */ struct sched_entity *curr, *next, *last, *skip; +#ifdef CONFIG_SCHED_DEBUG unsigned int nr_spread_over; +#endif #ifdef CONFIG_FAIR_GROUP_SCHED struct rq *rq; /* cpu runqueue to which this cfs_rq is attached */ -- cgit v1.1 From 7142d17e8f935fa842e9f6eece2281b6d41625d6 Mon Sep 17 00:00:00 2001 From: Hillf Danton Date: Thu, 5 May 2011 20:53:20 +0800 Subject: sched: Shorten the construction of the span cpu mask of sched domain For a given node, when constructing the cpumask for its sched_domain to span, if there is no best node available after searching, further efforts could be saved, based on small change in the return value of find_next_best_node(). Signed-off-by: Hillf Danton Cc: Peter Zijlstra Cc: Mike Galbraith Cc: Yong Zhang Link: http://lkml.kernel.org/r/BANLkTi%3DqPWxRAa6%2BdT3ohEP6Z%3D0v%2Be4EXA@mail.gmail.com Signed-off-by: Ingo Molnar --- kernel/sched.c | 8 +++++--- 1 file changed, 5 insertions(+), 3 deletions(-) (limited to 'kernel') diff --git a/kernel/sched.c b/kernel/sched.c index 3d8a1b2..da93381 100644 --- a/kernel/sched.c +++ b/kernel/sched.c @@ -6807,7 +6807,7 @@ __setup("isolcpus=", isolated_cpu_setup); */ static int find_next_best_node(int node, nodemask_t *used_nodes) { - int i, n, val, min_val, best_node = 0; + int i, n, val, min_val, best_node = -1; min_val = INT_MAX; @@ -6831,7 +6831,8 @@ static int find_next_best_node(int node, nodemask_t *used_nodes) } } - node_set(best_node, *used_nodes); + if (best_node != -1) + node_set(best_node, *used_nodes); return best_node; } @@ -6857,7 +6858,8 @@ static void sched_domain_node_span(int node, struct cpumask *span) for (i = 1; i < SD_NODES_PER_DOMAIN; i++) { int next_node = find_next_best_node(node, &used_nodes); - + if (next_node < 0) + break; cpumask_or(span, span, cpumask_of_node(next_node)); } } -- cgit v1.1 From a3a4a5acd3bd2f6f1e102e1f1b9d2e2bb320a7fd Mon Sep 17 00:00:00 2001 From: Arjan van de Ven Date: Thu, 5 May 2011 23:55:18 -0400 Subject: Regression: partial revert "tracing: Remove lock_depth from event entry" This partially reverts commit e6e1e2593592a8f6f6380496655d8c6f67431266. That commit changed the structure layout of the trace structure, which in turn broke PowerTOP (1.9x generation) quite badly. I appreciate not wanting to expose the variable in question, and PowerTOP was not using it, so I've replaced the variable with just a padding field - that way if in the future a new field is needed it can just use this padding field. Signed-off-by: Arjan van de Ven Signed-off-by: Linus Torvalds --- kernel/trace/trace.c | 1 + kernel/trace/trace_events.c | 1 + 2 files changed, 2 insertions(+) (limited to 'kernel') diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c index d38c16a..1cb49be 100644 --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -1110,6 +1110,7 @@ tracing_generic_entry_update(struct trace_entry *entry, unsigned long flags, entry->preempt_count = pc & 0xff; entry->pid = (tsk) ? tsk->pid : 0; + entry->padding = 0; entry->flags = #ifdef CONFIG_TRACE_IRQFLAGS_SUPPORT (irqs_disabled_flags(flags) ? TRACE_FLAG_IRQS_OFF : 0) | diff --git a/kernel/trace/trace_events.c b/kernel/trace/trace_events.c index e88f74f..2fe1103 100644 --- a/kernel/trace/trace_events.c +++ b/kernel/trace/trace_events.c @@ -116,6 +116,7 @@ static int trace_define_common_fields(void) __common_field(unsigned char, flags); __common_field(unsigned char, preempt_count); __common_field(int, pid); + __common_field(int, padding); return ret; } -- cgit v1.1 From b50fa7c8077c625919b1e0a75fc37b825f024518 Mon Sep 17 00:00:00 2001 From: Kay Sievers Date: Thu, 5 May 2011 13:32:05 +0200 Subject: reboot: disable usermodehelper to prevent fs access In case CONFIG_UEVENT_HELPER_PATH is not set to "", which it should be on every system, the kernel forks processes during shutdown, which try to access the rootfs, even when the binary does not exist. It causes exceptions and long delays in the disk driver, which gets read requests at the time it tries to shut down the disk. This patch disables all kernel-forked processes during reboot to allow a clean poweroff. Cc: Tejun Heo Tested-By: Anton Guda Signed-off-by: Kay Sievers Signed-off-by: Greg Kroah-Hartman --- kernel/sys.c | 2 ++ 1 file changed, 2 insertions(+) (limited to 'kernel') diff --git a/kernel/sys.c b/kernel/sys.c index af468ed..70c4c51 100644 --- a/kernel/sys.c +++ b/kernel/sys.c @@ -314,6 +314,7 @@ void kernel_restart_prepare(char *cmd) { blocking_notifier_call_chain(&reboot_notifier_list, SYS_RESTART, cmd); system_state = SYSTEM_RESTART; + usermodehelper_disable(); device_shutdown(); sysdev_shutdown(); syscore_shutdown(); @@ -344,6 +345,7 @@ static void kernel_shutdown_prepare(enum system_states state) blocking_notifier_call_chain(&reboot_notifier_list, (state == SYSTEM_HALT)?SYS_HALT:SYS_POWER_OFF, NULL); system_state = state; + usermodehelper_disable(); device_shutdown(); } /** -- cgit v1.1 From 1217ed1ba5c67393293dfb0f03c353b118dadeb4 Mon Sep 17 00:00:00 2001 From: "Paul E. McKenney" Date: Wed, 4 May 2011 21:43:49 -0700 Subject: rcu: permit rcu_read_unlock() to be called while holding runqueue locks Avoid calling into the scheduler while holding core RCU locks. This allows rcu_read_unlock() to be called while holding the runqueue locks, but only as long as there was no chance of the RCU read-side critical section having been preempted. (Otherwise, if RCU priority boosting is enabled, rcu_read_unlock() might call into the scheduler in order to unboost itself, which might allows self-deadlock on the runqueue locks within the scheduler.) Signed-off-by: Paul E. McKenney Signed-off-by: Paul E. McKenney --- kernel/rcutree.c | 44 ++++++++++------------------------ kernel/rcutree.h | 5 +--- kernel/rcutree_plugin.h | 64 ++++++++++++++++--------------------------------- 3 files changed, 34 insertions(+), 79 deletions(-) (limited to 'kernel') diff --git a/kernel/rcutree.c b/kernel/rcutree.c index 54ff7eb..5616b17 100644 --- a/kernel/rcutree.c +++ b/kernel/rcutree.c @@ -1133,22 +1133,7 @@ static void __rcu_offline_cpu(int cpu, struct rcu_state *rsp) raw_spin_unlock_irqrestore(&rnp->lock, flags); if (need_report & RCU_OFL_TASKS_EXP_GP) rcu_report_exp_rnp(rsp, rnp); - - /* - * If there are no more online CPUs for this rcu_node structure, - * kill the rcu_node structure's kthread. Otherwise, adjust its - * affinity. - */ - t = rnp->node_kthread_task; - if (t != NULL && - rnp->qsmaskinit == 0) { - raw_spin_lock_irqsave(&rnp->lock, flags); - rnp->node_kthread_task = NULL; - raw_spin_unlock_irqrestore(&rnp->lock, flags); - kthread_stop(t); - rcu_stop_boost_kthread(rnp); - } else - rcu_node_kthread_setaffinity(rnp, -1); + rcu_node_kthread_setaffinity(rnp, -1); } /* @@ -1320,8 +1305,7 @@ static void force_qs_rnp(struct rcu_state *rsp, int (*f)(struct rcu_data *)) return; } if (rnp->qsmask == 0) { - rcu_initiate_boost(rnp); - raw_spin_unlock_irqrestore(&rnp->lock, flags); + rcu_initiate_boost(rnp, flags); /* releases rnp->lock */ continue; } cpu = rnp->grplo; @@ -1340,10 +1324,10 @@ static void force_qs_rnp(struct rcu_state *rsp, int (*f)(struct rcu_data *)) raw_spin_unlock_irqrestore(&rnp->lock, flags); } rnp = rcu_get_root(rsp); - raw_spin_lock_irqsave(&rnp->lock, flags); - if (rnp->qsmask == 0) - rcu_initiate_boost(rnp); - raw_spin_unlock_irqrestore(&rnp->lock, flags); + if (rnp->qsmask == 0) { + raw_spin_lock_irqsave(&rnp->lock, flags); + rcu_initiate_boost(rnp, flags); /* releases rnp->lock. */ + } } /* @@ -1497,7 +1481,8 @@ static void invoke_rcu_cpu_kthread(void) /* * Wake up the specified per-rcu_node-structure kthread. - * The caller must hold ->lock. + * Because the per-rcu_node kthreads are immortal, we don't need + * to do anything to keep them alive. */ static void invoke_rcu_node_kthread(struct rcu_node *rnp) { @@ -1546,8 +1531,8 @@ static void rcu_cpu_kthread_timer(unsigned long arg) raw_spin_lock_irqsave(&rnp->lock, flags); rnp->wakemask |= rdp->grpmask; - invoke_rcu_node_kthread(rnp); raw_spin_unlock_irqrestore(&rnp->lock, flags); + invoke_rcu_node_kthread(rnp); } /* @@ -1694,16 +1679,12 @@ static int rcu_node_kthread(void *arg) for (;;) { rnp->node_kthread_status = RCU_KTHREAD_WAITING; - wait_event_interruptible(rnp->node_wq, rnp->wakemask != 0 || - kthread_should_stop()); - if (kthread_should_stop()) - break; + wait_event_interruptible(rnp->node_wq, rnp->wakemask != 0); rnp->node_kthread_status = RCU_KTHREAD_RUNNING; raw_spin_lock_irqsave(&rnp->lock, flags); mask = rnp->wakemask; rnp->wakemask = 0; - rcu_initiate_boost(rnp); - raw_spin_unlock_irqrestore(&rnp->lock, flags); + rcu_initiate_boost(rnp, flags); /* releases rnp->lock. */ for (cpu = rnp->grplo; cpu <= rnp->grphi; cpu++, mask >>= 1) { if ((mask & 0x1) == 0) continue; @@ -1719,6 +1700,7 @@ static int rcu_node_kthread(void *arg) preempt_enable(); } } + /* NOTREACHED */ rnp->node_kthread_status = RCU_KTHREAD_STOPPED; return 0; } @@ -1738,7 +1720,7 @@ static void rcu_node_kthread_setaffinity(struct rcu_node *rnp, int outgoingcpu) int cpu; unsigned long mask = rnp->qsmaskinit; - if (rnp->node_kthread_task == NULL || mask == 0) + if (rnp->node_kthread_task == NULL) return; if (!alloc_cpumask_var(&cm, GFP_KERNEL)) return; diff --git a/kernel/rcutree.h b/kernel/rcutree.h index a6a9717..93d4a1c 100644 --- a/kernel/rcutree.h +++ b/kernel/rcutree.h @@ -444,15 +444,12 @@ static void rcu_preempt_send_cbs_to_online(void); static void __init __rcu_init_preempt(void); static void rcu_needs_cpu_flush(void); static void __init rcu_init_boost_waitqueue(struct rcu_node *rnp); -static void rcu_initiate_boost(struct rcu_node *rnp); +static void rcu_initiate_boost(struct rcu_node *rnp, unsigned long flags); static void rcu_boost_kthread_setaffinity(struct rcu_node *rnp, cpumask_var_t cm); static void rcu_preempt_boost_start_gp(struct rcu_node *rnp); static int __cpuinit rcu_spawn_one_boost_kthread(struct rcu_state *rsp, struct rcu_node *rnp, int rnp_index); -#ifdef CONFIG_HOTPLUG_CPU -static void rcu_stop_boost_kthread(struct rcu_node *rnp); -#endif /* #ifdef CONFIG_HOTPLUG_CPU */ #endif /* #ifndef RCU_TREE_NONCORE */ diff --git a/kernel/rcutree_plugin.h b/kernel/rcutree_plugin.h index f629479..ed339702 100644 --- a/kernel/rcutree_plugin.h +++ b/kernel/rcutree_plugin.h @@ -711,15 +711,17 @@ static void rcu_report_exp_rnp(struct rcu_state *rsp, struct rcu_node *rnp) static void sync_rcu_preempt_exp_init(struct rcu_state *rsp, struct rcu_node *rnp) { + unsigned long flags; int must_wait = 0; - raw_spin_lock(&rnp->lock); /* irqs already disabled */ - if (!list_empty(&rnp->blkd_tasks)) { + raw_spin_lock_irqsave(&rnp->lock, flags); + if (list_empty(&rnp->blkd_tasks)) + raw_spin_unlock_irqrestore(&rnp->lock, flags); + else { rnp->exp_tasks = rnp->blkd_tasks.next; - rcu_initiate_boost(rnp); + rcu_initiate_boost(rnp, flags); /* releases rnp->lock */ must_wait = 1; } - raw_spin_unlock(&rnp->lock); /* irqs remain disabled */ if (!must_wait) rcu_report_exp_rnp(rsp, rnp); } @@ -1179,12 +1181,7 @@ static int rcu_boost(struct rcu_node *rnp) */ static void rcu_boost_kthread_timer(unsigned long arg) { - unsigned long flags; - struct rcu_node *rnp = (struct rcu_node *)arg; - - raw_spin_lock_irqsave(&rnp->lock, flags); - invoke_rcu_node_kthread(rnp); - raw_spin_unlock_irqrestore(&rnp->lock, flags); + invoke_rcu_node_kthread((struct rcu_node *)arg); } /* @@ -1200,10 +1197,7 @@ static int rcu_boost_kthread(void *arg) for (;;) { rnp->boost_kthread_status = RCU_KTHREAD_WAITING; wait_event_interruptible(rnp->boost_wq, rnp->boost_tasks || - rnp->exp_tasks || - kthread_should_stop()); - if (kthread_should_stop()) - break; + rnp->exp_tasks); rnp->boost_kthread_status = RCU_KTHREAD_RUNNING; more2boost = rcu_boost(rnp); if (more2boost) @@ -1215,7 +1209,7 @@ static int rcu_boost_kthread(void *arg) spincnt = 0; } } - rnp->boost_kthread_status = RCU_KTHREAD_STOPPED; + /* NOTREACHED */ return 0; } @@ -1225,14 +1219,17 @@ static int rcu_boost_kthread(void *arg) * kthread to start boosting them. If there is an expedited grace * period in progress, it is always time to boost. * - * The caller must hold rnp->lock. + * The caller must hold rnp->lock, which this function releases, + * but irqs remain disabled. The ->boost_kthread_task is immortal, + * so we don't need to worry about it going away. */ -static void rcu_initiate_boost(struct rcu_node *rnp) +static void rcu_initiate_boost(struct rcu_node *rnp, unsigned long flags) { struct task_struct *t; if (!rcu_preempt_blocked_readers_cgp(rnp) && rnp->exp_tasks == NULL) { rnp->n_balk_exp_gp_tasks++; + raw_spin_unlock_irqrestore(&rnp->lock, flags); return; } if (rnp->exp_tasks != NULL || @@ -1242,11 +1239,14 @@ static void rcu_initiate_boost(struct rcu_node *rnp) ULONG_CMP_GE(jiffies, rnp->boost_time))) { if (rnp->exp_tasks == NULL) rnp->boost_tasks = rnp->gp_tasks; + raw_spin_unlock_irqrestore(&rnp->lock, flags); t = rnp->boost_kthread_task; if (t != NULL) wake_up_process(t); - } else + } else { rcu_initiate_boost_trace(rnp); + raw_spin_unlock_irqrestore(&rnp->lock, flags); + } } /* @@ -1312,27 +1312,11 @@ static int __cpuinit rcu_spawn_one_boost_kthread(struct rcu_state *rsp, return 0; } -#ifdef CONFIG_HOTPLUG_CPU - -static void rcu_stop_boost_kthread(struct rcu_node *rnp) -{ - unsigned long flags; - struct task_struct *t; - - raw_spin_lock_irqsave(&rnp->lock, flags); - t = rnp->boost_kthread_task; - rnp->boost_kthread_task = NULL; - raw_spin_unlock_irqrestore(&rnp->lock, flags); - if (t != NULL) - kthread_stop(t); -} - -#endif /* #ifdef CONFIG_HOTPLUG_CPU */ - #else /* #ifdef CONFIG_RCU_BOOST */ -static void rcu_initiate_boost(struct rcu_node *rnp) +static void rcu_initiate_boost(struct rcu_node *rnp, unsigned long flags) { + raw_spin_unlock_irqrestore(&rnp->lock, flags); } static void rcu_boost_kthread_setaffinity(struct rcu_node *rnp, @@ -1355,14 +1339,6 @@ static int __cpuinit rcu_spawn_one_boost_kthread(struct rcu_state *rsp, return 0; } -#ifdef CONFIG_HOTPLUG_CPU - -static void rcu_stop_boost_kthread(struct rcu_node *rnp) -{ -} - -#endif /* #ifdef CONFIG_HOTPLUG_CPU */ - #endif /* #else #ifdef CONFIG_RCU_BOOST */ #ifndef CONFIG_SMP -- cgit v1.1 From 30088ad815802f850f26114920ccf9effd4bc520 Mon Sep 17 00:00:00 2001 From: Lai Jiangshan Date: Tue, 15 Mar 2011 17:53:46 +0800 Subject: cgroup,rcu: convert call_rcu(free_css_set_rcu) to kfree_rcu() The rcu callback free_css_set_rcu() just calls a kfree(), so we use kfree_rcu() instead of the call_rcu(free_css_set_rcu). Signed-off-by: Lai Jiangshan Acked-by: Paul Menage Signed-off-by: Paul E. McKenney Reviewed-by: Josh Triplett --- kernel/cgroup.c | 8 +------- 1 file changed, 1 insertion(+), 7 deletions(-) (limited to 'kernel') diff --git a/kernel/cgroup.c b/kernel/cgroup.c index 25c7eb5..d5160a8 100644 --- a/kernel/cgroup.c +++ b/kernel/cgroup.c @@ -326,12 +326,6 @@ static struct hlist_head *css_set_hash(struct cgroup_subsys_state *css[]) return &css_set_table[index]; } -static void free_css_set_rcu(struct rcu_head *obj) -{ - struct css_set *cg = container_of(obj, struct css_set, rcu_head); - kfree(cg); -} - /* We don't maintain the lists running through each css_set to its * task until after the first call to cgroup_iter_start(). This * reduces the fork()/exit() overhead for people who have cgroups @@ -375,7 +369,7 @@ static void __put_css_set(struct css_set *cg, int taskexit) } write_unlock(&css_set_lock); - call_rcu(&cg->rcu_head, free_css_set_rcu); + kfree_rcu(cg, rcu_head); } /* -- cgit v1.1 From f2da1c40dc003939f616f27a103b2592f1424b07 Mon Sep 17 00:00:00 2001 From: Lai Jiangshan Date: Tue, 15 Mar 2011 17:55:16 +0800 Subject: cgroup,rcu: convert call_rcu(free_cgroup_rcu) to kfree_rcu() The rcu callback free_cgroup_rcu() just calls a kfree(), so we use kfree_rcu() instead of the call_rcu(free_cgroup_rcu). Signed-off-by: Lai Jiangshan Acked-by: Paul Menage Signed-off-by: Paul E. McKenney Reviewed-by: Josh Triplett --- kernel/cgroup.c | 9 +-------- 1 file changed, 1 insertion(+), 8 deletions(-) (limited to 'kernel') diff --git a/kernel/cgroup.c b/kernel/cgroup.c index d5160a8..20451ce 100644 --- a/kernel/cgroup.c +++ b/kernel/cgroup.c @@ -806,13 +806,6 @@ static int cgroup_call_pre_destroy(struct cgroup *cgrp) return ret; } -static void free_cgroup_rcu(struct rcu_head *obj) -{ - struct cgroup *cgrp = container_of(obj, struct cgroup, rcu_head); - - kfree(cgrp); -} - static void cgroup_diput(struct dentry *dentry, struct inode *inode) { /* is dentry a directory ? if so, kfree() associated cgroup */ @@ -850,7 +843,7 @@ static void cgroup_diput(struct dentry *dentry, struct inode *inode) */ BUG_ON(!list_empty(&cgrp->pidlists)); - call_rcu(&cgrp->rcu_head, free_cgroup_rcu); + kfree_rcu(cgrp, rcu_head); } iput(inode); } -- cgit v1.1 From 025cea99db3fb110ebc8ede5ff647833fab9574f Mon Sep 17 00:00:00 2001 From: Lai Jiangshan Date: Tue, 15 Mar 2011 17:56:10 +0800 Subject: cgroup,rcu: convert call_rcu(__free_css_id_cb) to kfree_rcu() The rcu callback __free_css_id_cb() just calls a kfree(), so we use kfree_rcu() instead of the call_rcu(__free_css_id_cb). Signed-off-by: Lai Jiangshan Acked-by: Paul Menage Signed-off-by: Paul E. McKenney Reviewed-by: Josh Triplett --- kernel/cgroup.c | 10 +--------- 1 file changed, 1 insertion(+), 9 deletions(-) (limited to 'kernel') diff --git a/kernel/cgroup.c b/kernel/cgroup.c index 20451ce..909a355 100644 --- a/kernel/cgroup.c +++ b/kernel/cgroup.c @@ -4610,14 +4610,6 @@ bool css_is_ancestor(struct cgroup_subsys_state *child, return ret; } -static void __free_css_id_cb(struct rcu_head *head) -{ - struct css_id *id; - - id = container_of(head, struct css_id, rcu_head); - kfree(id); -} - void free_css_id(struct cgroup_subsys *ss, struct cgroup_subsys_state *css) { struct css_id *id = css->id; @@ -4632,7 +4624,7 @@ void free_css_id(struct cgroup_subsys *ss, struct cgroup_subsys_state *css) spin_lock(&ss->id_lock); idr_remove(&ss->idr, id->id); spin_unlock(&ss->id_lock); - call_rcu(&id->rcu_head, __free_css_id_cb); + kfree_rcu(id, rcu_head); } EXPORT_SYMBOL_GPL(free_css_id); -- cgit v1.1 From cb796ff338db9f064f4ecb7d41898e8bedcad4d9 Mon Sep 17 00:00:00 2001 From: Lai Jiangshan Date: Fri, 18 Mar 2011 12:07:41 +0800 Subject: perf,rcu: convert call_rcu(free_ctx) to kfree_rcu() The rcu callback free_ctx() just calls a kfree(), so we use kfree_rcu() instead of the call_rcu(free_ctx). Signed-off-by: Lai Jiangshan Acked-by: Peter Zijlstra Signed-off-by: Paul E. McKenney Reviewed-by: Josh Triplett --- kernel/perf_event.c | 10 +--------- 1 file changed, 1 insertion(+), 9 deletions(-) (limited to 'kernel') diff --git a/kernel/perf_event.c b/kernel/perf_event.c index 8e81a98..17a176f 100644 --- a/kernel/perf_event.c +++ b/kernel/perf_event.c @@ -586,14 +586,6 @@ static void get_ctx(struct perf_event_context *ctx) WARN_ON(!atomic_inc_not_zero(&ctx->refcount)); } -static void free_ctx(struct rcu_head *head) -{ - struct perf_event_context *ctx; - - ctx = container_of(head, struct perf_event_context, rcu_head); - kfree(ctx); -} - static void put_ctx(struct perf_event_context *ctx) { if (atomic_dec_and_test(&ctx->refcount)) { @@ -601,7 +593,7 @@ static void put_ctx(struct perf_event_context *ctx) put_ctx(ctx->parent_ctx); if (ctx->task) put_task_struct(ctx->task); - call_rcu(&ctx->rcu_head, free_ctx); + kfree_rcu(ctx, rcu_head); } } -- cgit v1.1 From fa4bbc4ca5795fbf1303b98c924e51a21a920f14 Mon Sep 17 00:00:00 2001 From: Lai Jiangshan Date: Fri, 18 Mar 2011 12:08:29 +0800 Subject: perf,rcu: convert call_rcu(swevent_hlist_release_rcu) to kfree_rcu() The rcu callback swevent_hlist_release_rcu() just calls a kfree(), so we use kfree_rcu() instead of the call_rcu(swevent_hlist_release_rcu). Signed-off-by: Lai Jiangshan Acked-by: Peter Zijlstra Signed-off-by: Paul E. McKenney Reviewed-by: Josh Triplett --- kernel/perf_event.c | 10 +--------- 1 file changed, 1 insertion(+), 9 deletions(-) (limited to 'kernel') diff --git a/kernel/perf_event.c b/kernel/perf_event.c index 17a176f..b90d660 100644 --- a/kernel/perf_event.c +++ b/kernel/perf_event.c @@ -5323,14 +5323,6 @@ swevent_hlist_deref(struct swevent_htable *swhash) lockdep_is_held(&swhash->hlist_mutex)); } -static void swevent_hlist_release_rcu(struct rcu_head *rcu_head) -{ - struct swevent_hlist *hlist; - - hlist = container_of(rcu_head, struct swevent_hlist, rcu_head); - kfree(hlist); -} - static void swevent_hlist_release(struct swevent_htable *swhash) { struct swevent_hlist *hlist = swevent_hlist_deref(swhash); @@ -5339,7 +5331,7 @@ static void swevent_hlist_release(struct swevent_htable *swhash) return; rcu_assign_pointer(swhash->swevent_hlist, NULL); - call_rcu(&hlist->rcu_head, swevent_hlist_release_rcu); + kfree_rcu(hlist, rcu_head); } static void swevent_hlist_put_cpu(struct perf_event *event, int cpu) -- cgit v1.1 From 87186475a402391a1ca7d42a675c9b35a18dc348 Mon Sep 17 00:00:00 2001 From: "Rafael J. Wysocki" Date: Tue, 10 May 2011 21:09:53 +0200 Subject: PM: Fix warning in pm_restrict_gfp_mask() during SNAPSHOT_S2RAM ioctl A warning is printed by pm_restrict_gfp_mask() while the SNAPSHOT_S2RAM ioctl is being executed after creating a hibernation image, because pm_restrict_gfp_mask() has been called once already before the image creation and suspend_devices_and_enter() calls it once again. This happens after commit 452aa6999e6703ffbddd7f6ea124d3 (mm/pm: force GFP_NOIO during suspend/hibernation and resume). To avoid this issue, move pm_restrict_gfp_mask() and pm_restore_gfp_mask() from suspend_devices_and_enter() to its caller in kernel/power/suspend.c. Reported-by: Alexandre Felipe Muller de Souza Signed-off-by: Rafael J. Wysocki Cc: stable@kernel.org --- kernel/power/suspend.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) (limited to 'kernel') diff --git a/kernel/power/suspend.c b/kernel/power/suspend.c index 8935369..6275970 100644 --- a/kernel/power/suspend.c +++ b/kernel/power/suspend.c @@ -216,7 +216,6 @@ int suspend_devices_and_enter(suspend_state_t state) goto Close; } suspend_console(); - pm_restrict_gfp_mask(); suspend_test_start(); error = dpm_suspend_start(PMSG_SUSPEND); if (error) { @@ -233,7 +232,6 @@ int suspend_devices_and_enter(suspend_state_t state) suspend_test_start(); dpm_resume_end(PMSG_RESUME); suspend_test_finish("resume devices"); - pm_restore_gfp_mask(); resume_console(); Close: if (suspend_ops->end) @@ -294,7 +292,9 @@ int enter_state(suspend_state_t state) goto Finish; pr_debug("PM: Entering %s sleep\n", pm_states[state]); + pm_restrict_gfp_mask(); error = suspend_devices_and_enter(state); + pm_restore_gfp_mask(); Finish: pr_debug("PM: Finishing wakeup.\n"); -- cgit v1.1 From 9744997a8a2280e67984d4bffd87221d24f3b6b1 Mon Sep 17 00:00:00 2001 From: "Rafael J. Wysocki" Date: Tue, 10 May 2011 21:10:01 +0200 Subject: PM / Hibernate: Make snapshot_release() restore GFP mask If the process using the hibernate user space interface closes /dev/snapshot after creating a hibernation image without thawing tasks, snapshot_release() should call pm_restore_gfp_mask() to restore the GFP mask used before the creation of the image. Make that happen. Tested-by: Alexandre Felipe Muller de Souza Signed-off-by: Rafael J. Wysocki Cc: stable@kernel.org --- kernel/power/user.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) (limited to 'kernel') diff --git a/kernel/power/user.c b/kernel/power/user.c index c36c3b9..6522be9 100644 --- a/kernel/power/user.c +++ b/kernel/power/user.c @@ -135,8 +135,10 @@ static int snapshot_release(struct inode *inode, struct file *filp) free_basic_memory_bitmaps(); data = filp->private_data; free_all_swap_pages(data->swap); - if (data->frozen) + if (data->frozen) { + pm_restore_gfp_mask(); thaw_processes(); + } pm_notifier_call_chain(data->mode == O_RDONLY ? PM_POST_HIBERNATION : PM_POST_RESTORE); atomic_inc(&snapshot_device_available); -- cgit v1.1 From 36cb7035ea0c11ef2c7fa2bbe0cd181b23569b29 Mon Sep 17 00:00:00 2001 From: "Rafael J. Wysocki" Date: Tue, 10 May 2011 21:10:13 +0200 Subject: PM / Hibernate: Fix ioctl SNAPSHOT_S2RAM The SNAPSHOT_S2RAM ioctl used for implementing the feature allowing one to suspend to RAM after creating a hibernation image is currently broken, because it doesn't clear the "ready" flag in the struct snapshot_data object handled by it. As a result, the SNAPSHOT_UNFREEZE doesn't work correctly after SNAPSHOT_S2RAM has returned and the user space hibernate task cannot thaw the other processes as appropriate. Make SNAPSHOT_S2RAM clear data->ready to fix this problem. Tested-by: Alexandre Felipe Muller de Souza Signed-off-by: Rafael J. Wysocki Cc: stable@kernel.org --- kernel/power/user.c | 1 + 1 file changed, 1 insertion(+) (limited to 'kernel') diff --git a/kernel/power/user.c b/kernel/power/user.c index 6522be9..7d02d33 100644 --- a/kernel/power/user.c +++ b/kernel/power/user.c @@ -381,6 +381,7 @@ static long snapshot_ioctl(struct file *filp, unsigned int cmd, * PM_HIBERNATION_PREPARE */ error = suspend_devices_and_enter(PM_SUSPEND_MEM); + data->ready = 0; break; case SNAPSHOT_PLATFORM_SUPPORT: -- cgit v1.1 From 2e711c04dbbf7a7732a3f7073b1fc285d12b369d Mon Sep 17 00:00:00 2001 From: "Rafael J. Wysocki" Date: Tue, 26 Apr 2011 19:15:07 +0200 Subject: PM: Remove sysdev suspend, resume and shutdown operations Since suspend, resume and shutdown operations in struct sysdev_class and struct sysdev_driver are not used any more, remove them. Also drop sysdev_suspend(), sysdev_resume() and sysdev_shutdown() used for executing those operations and modify all of their users accordingly. This reduces kernel code size quite a bit and reduces its complexity. Signed-off-by: Rafael J. Wysocki Acked-by: Greg Kroah-Hartman --- kernel/kexec.c | 9 +-------- kernel/power/hibernate.c | 18 ++---------------- kernel/power/suspend.c | 8 +------- kernel/sys.c | 3 --- 4 files changed, 4 insertions(+), 34 deletions(-) (limited to 'kernel') diff --git a/kernel/kexec.c b/kernel/kexec.c index 87b77de..8d814cb 100644 --- a/kernel/kexec.c +++ b/kernel/kexec.c @@ -1531,13 +1531,7 @@ int kernel_kexec(void) if (error) goto Enable_cpus; local_irq_disable(); - /* Suspend system devices */ - error = sysdev_suspend(PMSG_FREEZE); - if (!error) { - error = syscore_suspend(); - if (error) - sysdev_resume(); - } + error = syscore_suspend(); if (error) goto Enable_irqs; } else @@ -1553,7 +1547,6 @@ int kernel_kexec(void) #ifdef CONFIG_KEXEC_JUMP if (kexec_image->preserve_context) { syscore_resume(); - sysdev_resume(); Enable_irqs: local_irq_enable(); Enable_cpus: diff --git a/kernel/power/hibernate.c b/kernel/power/hibernate.c index 50aae66..554d3b0 100644 --- a/kernel/power/hibernate.c +++ b/kernel/power/hibernate.c @@ -272,12 +272,7 @@ static int create_image(int platform_mode) local_irq_disable(); - error = sysdev_suspend(PMSG_FREEZE); - if (!error) { - error = syscore_suspend(); - if (error) - sysdev_resume(); - } + error = syscore_suspend(); if (error) { printk(KERN_ERR "PM: Some system devices failed to power down, " "aborting hibernation\n"); @@ -302,7 +297,6 @@ static int create_image(int platform_mode) Power_up: syscore_resume(); - sysdev_resume(); /* NOTE: dpm_resume_noirq() is just a resume() for devices * that suspended with irqs off ... no overall powerup. */ @@ -409,12 +403,7 @@ static int resume_target_kernel(bool platform_mode) local_irq_disable(); - error = sysdev_suspend(PMSG_QUIESCE); - if (!error) { - error = syscore_suspend(); - if (error) - sysdev_resume(); - } + error = syscore_suspend(); if (error) goto Enable_irqs; @@ -442,7 +431,6 @@ static int resume_target_kernel(bool platform_mode) touch_softlockup_watchdog(); syscore_resume(); - sysdev_resume(); Enable_irqs: local_irq_enable(); @@ -528,7 +516,6 @@ int hibernation_platform_enter(void) goto Platform_finish; local_irq_disable(); - sysdev_suspend(PMSG_HIBERNATE); syscore_suspend(); if (pm_wakeup_pending()) { error = -EAGAIN; @@ -541,7 +528,6 @@ int hibernation_platform_enter(void) Power_up: syscore_resume(); - sysdev_resume(); local_irq_enable(); enable_nonboot_cpus(); diff --git a/kernel/power/suspend.c b/kernel/power/suspend.c index 8935369..732d77a 100644 --- a/kernel/power/suspend.c +++ b/kernel/power/suspend.c @@ -163,19 +163,13 @@ static int suspend_enter(suspend_state_t state) arch_suspend_disable_irqs(); BUG_ON(!irqs_disabled()); - error = sysdev_suspend(PMSG_SUSPEND); - if (!error) { - error = syscore_suspend(); - if (error) - sysdev_resume(); - } + error = syscore_suspend(); if (!error) { if (!(suspend_test(TEST_CORE) || pm_wakeup_pending())) { error = suspend_ops->enter(state); events_check_enabled = false; } syscore_resume(); - sysdev_resume(); } arch_suspend_enable_irqs(); diff --git a/kernel/sys.c b/kernel/sys.c index af468ed..f0c1038 100644 --- a/kernel/sys.c +++ b/kernel/sys.c @@ -315,7 +315,6 @@ void kernel_restart_prepare(char *cmd) blocking_notifier_call_chain(&reboot_notifier_list, SYS_RESTART, cmd); system_state = SYSTEM_RESTART; device_shutdown(); - sysdev_shutdown(); syscore_shutdown(); } @@ -354,7 +353,6 @@ static void kernel_shutdown_prepare(enum system_states state) void kernel_halt(void) { kernel_shutdown_prepare(SYSTEM_HALT); - sysdev_shutdown(); syscore_shutdown(); printk(KERN_EMERG "System halted.\n"); kmsg_dump(KMSG_DUMP_HALT); @@ -374,7 +372,6 @@ void kernel_power_off(void) if (pm_power_off_prepare) pm_power_off_prepare(); disable_nonboot_cpus(); - sysdev_shutdown(); syscore_shutdown(); printk(KERN_EMERG "Power down.\n"); kmsg_dump(KMSG_DUMP_POWEROFF); -- cgit v1.1 From 3e51e3edfd81bfd9853ad7de91167e4ce33d0fe7 Mon Sep 17 00:00:00 2001 From: Samir Bellabes Date: Wed, 11 May 2011 18:18:05 +0200 Subject: sched: Remove unused parameters from sched_fork() and wake_up_new_task() sched_fork() and wake_up_new_task() are defined with a parameter 'unsigned long clone_flags', which is unused. This patch removes the parameters. Signed-off-by: Samir Bellabes Acked-by: Peter Zijlstra Link: http://lkml.kernel.org/r/1305130685-1047-1-git-send-email-sam@synack.fr Signed-off-by: Ingo Molnar --- kernel/fork.c | 4 ++-- kernel/sched.c | 4 ++-- 2 files changed, 4 insertions(+), 4 deletions(-) (limited to 'kernel') diff --git a/kernel/fork.c b/kernel/fork.c index aca6287..2b44d82 100644 --- a/kernel/fork.c +++ b/kernel/fork.c @@ -1152,7 +1152,7 @@ static struct task_struct *copy_process(unsigned long clone_flags, #endif /* Perform scheduler related setup. Assign this task to a CPU. */ - sched_fork(p, clone_flags); + sched_fork(p); retval = perf_event_init_task(p); if (retval) @@ -1463,7 +1463,7 @@ long do_fork(unsigned long clone_flags, */ p->flags &= ~PF_STARTING; - wake_up_new_task(p, clone_flags); + wake_up_new_task(p); tracehook_report_clone_complete(trace, regs, clone_flags, nr, p); diff --git a/kernel/sched.c b/kernel/sched.c index da93381..f9778c0 100644 --- a/kernel/sched.c +++ b/kernel/sched.c @@ -2741,7 +2741,7 @@ static void __sched_fork(struct task_struct *p) /* * fork()/clone()-time setup: */ -void sched_fork(struct task_struct *p, int clone_flags) +void sched_fork(struct task_struct *p) { unsigned long flags; int cpu = get_cpu(); @@ -2823,7 +2823,7 @@ void sched_fork(struct task_struct *p, int clone_flags) * that must be done for every newly created context, then puts the task * on the runqueue and wakes it. */ -void wake_up_new_task(struct task_struct *p, unsigned long clone_flags) +void wake_up_new_task(struct task_struct *p) { unsigned long flags; struct rq *rq; -- cgit v1.1 From 47a150edc2ae734c0f4bf50aa19499e23b9a46f8 Mon Sep 17 00:00:00 2001 From: "Serge E. Hallyn" Date: Fri, 13 May 2011 04:27:54 +0100 Subject: Cache user_ns in struct cred If !CONFIG_USERNS, have current_user_ns() defined to (&init_user_ns). Get rid of _current_user_ns. This requires nsown_capable() to be defined in capability.c rather than as static inline in capability.h, so do that. Request_key needs init_user_ns defined at current_user_ns if !CONFIG_USERNS, so forward-declare that in cred.h if !CONFIG_USERNS at current_user_ns() define. Compile-tested with and without CONFIG_USERNS. Signed-off-by: Serge E. Hallyn [ This makes a huge performance difference for acl_permission_check(), up to 30%. And that is one of the hottest kernel functions for loads that are pathname-lookup heavy. ] Signed-off-by: Linus Torvalds --- kernel/capability.c | 12 ++++++++++++ kernel/cred.c | 12 ++++++------ 2 files changed, 18 insertions(+), 6 deletions(-) (limited to 'kernel') diff --git a/kernel/capability.c b/kernel/capability.c index bf0c734..32a80e0 100644 --- a/kernel/capability.c +++ b/kernel/capability.c @@ -399,3 +399,15 @@ bool task_ns_capable(struct task_struct *t, int cap) return ns_capable(task_cred_xxx(t, user)->user_ns, cap); } EXPORT_SYMBOL(task_ns_capable); + +/** + * nsown_capable - Check superior capability to one's own user_ns + * @cap: The capability in question + * + * Return true if the current task has the given superior capability + * targeted at its own user namespace. + */ +bool nsown_capable(int cap) +{ + return ns_capable(current_user_ns(), cap); +} diff --git a/kernel/cred.c b/kernel/cred.c index 5557b55..8093c16 100644 --- a/kernel/cred.c +++ b/kernel/cred.c @@ -54,6 +54,7 @@ struct cred init_cred = { .cap_effective = CAP_INIT_EFF_SET, .cap_bset = CAP_INIT_BSET, .user = INIT_USER, + .user_ns = &init_user_ns, .group_info = &init_groups, #ifdef CONFIG_KEYS .tgcred = &init_tgcred, @@ -410,6 +411,11 @@ int copy_creds(struct task_struct *p, unsigned long clone_flags) goto error_put; } + /* cache user_ns in cred. Doesn't need a refcount because it will + * stay pinned by cred->user + */ + new->user_ns = new->user->user_ns; + #ifdef CONFIG_KEYS /* new threads get their own thread keyrings if their parent already * had one */ @@ -741,12 +747,6 @@ int set_create_files_as(struct cred *new, struct inode *inode) } EXPORT_SYMBOL(set_create_files_as); -struct user_namespace *current_user_ns(void) -{ - return _current_user_ns(); -} -EXPORT_SYMBOL(current_user_ns); - #ifdef CONFIG_DEBUG_CREDENTIALS bool creds_are_invalid(const struct cred *cred) -- cgit v1.1 From ec514c487c3d4b652943da7b0afbc094eee08cfa Mon Sep 17 00:00:00 2001 From: Cheng Xu Date: Sat, 14 May 2011 14:20:02 +0800 Subject: sched: Fix rt_rq runtime leakage bug This patch is to fix the real-time scheduler bug reported at: https://lkml.org/lkml/2011/4/26/13 That is, when running multiple real-time threads on every logical CPUs and then turning off one CPU, the kernel will bug at function __disable_runtime(). Function __disable_runtime() bugs and reports leakage of rt_rq runtime. The root cause is __disable_runtime() assumes it iterates through all the existing rt_rq's while walking rq->leaf_rt_rq_list, which actually contains only runnable rt_rq's. This problem also applies to __enable_runtime() and print_rt_stats(). The patch is based on above analysis, appears to fix the problem, but is only lightly tested. Reported-by: Paul E. McKenney Tested-by: Paul E. McKenney Signed-off-by: Cheng Xu Signed-off-by: Peter Zijlstra Link: http://lkml.kernel.org/r/4DCE1F12.6040609@linux.vnet.ibm.com Signed-off-by: Ingo Molnar --- kernel/sched_rt.c | 22 +++++++++++++++++++--- 1 file changed, 19 insertions(+), 3 deletions(-) (limited to 'kernel') diff --git a/kernel/sched_rt.c b/kernel/sched_rt.c index e7cebdc..f8fcf82 100644 --- a/kernel/sched_rt.c +++ b/kernel/sched_rt.c @@ -183,6 +183,14 @@ static inline u64 sched_rt_period(struct rt_rq *rt_rq) return ktime_to_ns(rt_rq->tg->rt_bandwidth.rt_period); } +typedef struct task_group *rt_rq_iter_t; + +#define for_each_rt_rq(rt_rq, iter, rq) \ + for (iter = list_entry_rcu(task_groups.next, typeof(*iter), list); \ + (&iter->list != &task_groups) && \ + (rt_rq = iter->rt_rq[cpu_of(rq)]); \ + iter = list_entry_rcu(iter->list.next, typeof(*iter), list)) + static inline void list_add_leaf_rt_rq(struct rt_rq *rt_rq) { list_add_rcu(&rt_rq->leaf_rt_rq_list, @@ -288,6 +296,11 @@ static inline u64 sched_rt_period(struct rt_rq *rt_rq) return ktime_to_ns(def_rt_bandwidth.rt_period); } +typedef struct rt_rq *rt_rq_iter_t; + +#define for_each_rt_rq(rt_rq, iter, rq) \ + for ((void) iter, rt_rq = &rq->rt; rt_rq; rt_rq = NULL) + static inline void list_add_leaf_rt_rq(struct rt_rq *rt_rq) { } @@ -402,12 +415,13 @@ next: static void __disable_runtime(struct rq *rq) { struct root_domain *rd = rq->rd; + rt_rq_iter_t iter; struct rt_rq *rt_rq; if (unlikely(!scheduler_running)) return; - for_each_leaf_rt_rq(rt_rq, rq) { + for_each_rt_rq(rt_rq, iter, rq) { struct rt_bandwidth *rt_b = sched_rt_bandwidth(rt_rq); s64 want; int i; @@ -487,6 +501,7 @@ static void disable_runtime(struct rq *rq) static void __enable_runtime(struct rq *rq) { + rt_rq_iter_t iter; struct rt_rq *rt_rq; if (unlikely(!scheduler_running)) @@ -495,7 +510,7 @@ static void __enable_runtime(struct rq *rq) /* * Reset each runqueue's bandwidth settings */ - for_each_leaf_rt_rq(rt_rq, rq) { + for_each_rt_rq(rt_rq, iter, rq) { struct rt_bandwidth *rt_b = sched_rt_bandwidth(rt_rq); raw_spin_lock(&rt_b->rt_runtime_lock); @@ -1796,10 +1811,11 @@ extern void print_rt_rq(struct seq_file *m, int cpu, struct rt_rq *rt_rq); static void print_rt_stats(struct seq_file *m, int cpu) { + rt_rq_iter_t iter; struct rt_rq *rt_rq; rcu_read_lock(); - for_each_leaf_rt_rq(rt_rq, cpu_rq(cpu)) + for_each_rt_rq(rt_rq, iter, cpu_rq(cpu)) print_rt_rq(m, cpu, rt_rq); rcu_read_unlock(); } -- cgit v1.1 From 61eadef6a9bde9ea62fda724a9cb501ce9bc925a Mon Sep 17 00:00:00 2001 From: Mike Galbraith Date: Fri, 29 Apr 2011 08:36:50 +0200 Subject: sched, rt: Update rq clock when unthrottling of an otherwise idle CPU If an RT task is awakened while it's rt_rq is throttled, the time between wakeup/enqueue and unthrottle/selection may be accounted as rt_time if the CPU is idle. Set rq->skip_clock_update negative upon throttle release to tell put_prev_task() that we need a clock update. Reported-by: Thomas Giesel Signed-off-by: Mike Galbraith Signed-off-by: Peter Zijlstra Link: http://lkml.kernel.org/r/1304059010.7472.1.camel@marge.simson.net Signed-off-by: Ingo Molnar --- kernel/sched.c | 6 +++--- kernel/sched_rt.c | 7 +++++++ 2 files changed, 10 insertions(+), 3 deletions(-) (limited to 'kernel') diff --git a/kernel/sched.c b/kernel/sched.c index f9778c0..b8b9a7d 100644 --- a/kernel/sched.c +++ b/kernel/sched.c @@ -466,7 +466,7 @@ struct rq { u64 nohz_stamp; unsigned char nohz_balance_kick; #endif - unsigned int skip_clock_update; + int skip_clock_update; /* capture load from *all* tasks on this cpu: */ struct load_weight load; @@ -652,7 +652,7 @@ static void update_rq_clock(struct rq *rq) { s64 delta; - if (rq->skip_clock_update) + if (rq->skip_clock_update > 0) return; delta = sched_clock_cpu(cpu_of(rq)) - rq->clock; @@ -4127,7 +4127,7 @@ static inline void schedule_debug(struct task_struct *prev) static void put_prev_task(struct rq *rq, struct task_struct *prev) { - if (prev->on_rq) + if (prev->on_rq || rq->skip_clock_update < 0) update_rq_clock(rq); prev->sched_class->put_prev_task(rq, prev); } diff --git a/kernel/sched_rt.c b/kernel/sched_rt.c index 19ecb31..0943ed7 100644 --- a/kernel/sched_rt.c +++ b/kernel/sched_rt.c @@ -562,6 +562,13 @@ static int do_sched_rt_period_timer(struct rt_bandwidth *rt_b, int overrun) if (rt_rq->rt_throttled && rt_rq->rt_time < runtime) { rt_rq->rt_throttled = 0; enqueue = 1; + + /* + * Force a clock update if the CPU was idle, + * lest wakeup -> unthrottle time accumulate. + */ + if (rt_rq->rt_nr_running && rq->curr == rq->idle) + rq->skip_clock_update = -1; } if (rt_rq->rt_time || rt_rq->rt_nr_running) idle = 0; -- cgit v1.1 From db44fc017d5989302713ab4e7f9e922b648f4b59 Mon Sep 17 00:00:00 2001 From: Yong Zhang Date: Mon, 9 May 2011 22:07:05 +0800 Subject: sched: Avoid going ahead if ->cpus_allowed is not changed If cpumask_equal(&p->cpus_allowed, new_mask) is true, seems there is no reason to prevent set_cpus_allowed_ptr() return directly. Signed-off-by: Yong Zhang Acked-by: Hillf Danton Signed-off-by: Peter Zijlstra Link: http://lkml.kernel.org/r/20110509140705.GA2219@zhy Signed-off-by: Ingo Molnar --- kernel/sched.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) (limited to 'kernel') diff --git a/kernel/sched.c b/kernel/sched.c index b8b9a7d..70bec4f 100644 --- a/kernel/sched.c +++ b/kernel/sched.c @@ -5946,13 +5946,15 @@ int set_cpus_allowed_ptr(struct task_struct *p, const struct cpumask *new_mask) rq = task_rq_lock(p, &flags); + if (cpumask_equal(&p->cpus_allowed, new_mask)) + goto out; + if (!cpumask_intersects(new_mask, cpu_active_mask)) { ret = -EINVAL; goto out; } - if (unlikely((p->flags & PF_THREAD_BOUND) && p != current && - !cpumask_equal(&p->cpus_allowed, new_mask))) { + if (unlikely((p->flags & PF_THREAD_BOUND) && p != current)) { ret = -EINVAL; goto out; } -- cgit v1.1 From db670dac49b5423b39b5e523d28fe32045d71b10 Mon Sep 17 00:00:00 2001 From: Stephan Baerwolf Date: Wed, 11 May 2011 18:03:29 +0200 Subject: sched: Fix and optimise calculation of the weight-inverse If the inverse loadweight should be zero, function "calc_delta_mine" calculates the inverse of "lw->weight" (in 32bit integer ops). This calculation is actually a little bit impure (because it is inverting something around "lw-weight"+1), especially when "lw->weight" becomes smaller. The correct inverse would be 1/lw->weight multiplied by "WMULT_CONST" for fixcomma-scaling it into integers. (So WMULT_CONST/lw->weight ...) The old, impure algorithm took two divisions for inverting lw->weight, the new, more exact one only takes one and an additional unlikely-if. Signed-off-by: Stephan Baerwolf Signed-off-by: Peter Zijlstra Cc: Linus Torvalds Link: http://lkml.kernel.org/n/tip-0pz0wnyalr4tk4ln11xwumdx@git.kernel.org [ This could explain some aritmetical issues for small shares but nothing concrete has been reported yet so we are not confident enough to queue this up in sched/urgent and for -stable backport. But if anyone finds this commit and sees it to fix some badness then we can certainly change our mind! ] Signed-off-by: Ingo Molnar --- kernel/sched.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) (limited to 'kernel') diff --git a/kernel/sched.c b/kernel/sched.c index 70bec4f..c62acf4 100644 --- a/kernel/sched.c +++ b/kernel/sched.c @@ -1330,15 +1330,15 @@ calc_delta_mine(unsigned long delta_exec, unsigned long weight, { u64 tmp; + tmp = (u64)delta_exec * weight; + if (!lw->inv_weight) { if (BITS_PER_LONG > 32 && unlikely(lw->weight >= WMULT_CONST)) lw->inv_weight = 1; else - lw->inv_weight = 1 + (WMULT_CONST-lw->weight/2) - / (lw->weight+1); + lw->inv_weight = WMULT_CONST / lw->weight; } - tmp = (u64)delta_exec * weight; /* * Check whether we'd overflow the 64-bit multiplication: */ -- cgit v1.1 From 07f4beb0b5bbfaf36a64aa00d59e670ec578a95a Mon Sep 17 00:00:00 2001 From: Thomas Gleixner Date: Mon, 16 May 2011 11:07:48 +0200 Subject: tick: Clear broadcast active bit when switching to oneshot The first cpu which switches from periodic to oneshot mode switches also the broadcast device into oneshot mode. The broadcast device serves as a backup for per cpu timers which stop in deeper C-states. To avoid starvation of the cpus which might be in idle and depend on broadcast mode it marks the other cpus as broadcast active and sets the brodcast expiry value of those cpus to the next tick. The oneshot mode broadcast bit for the other cpus is sticky and gets only cleared when those cpus exit idle. If a cpu was not idle while the bit got set in consequence the bit prevents that the broadcast device is armed on behalf of that cpu when it enters idle for the first time after it switched to oneshot mode. In most cases that goes unnoticed as one of the other cpus has usually a timer pending which keeps the broadcast device armed with a short timeout. Now if the only cpu which has a short timer active has the bit set then the broadcast device will not be armed on behalf of that cpu and will fire way after the expected timer expiry. In the case of Christians bug report it took ~145 seconds which is about half of the wrap around time of HPET (the limit for that device) due to the fact that all other cpus had no timers armed which expired before the 145 seconds timeframe. The solution is simply to clear the broadcast active bit unconditionally when a cpu switches to oneshot mode after the first cpu switched the broadcast device over. It's not idle at that point otherwise it would not be executing that code. [ I fundamentally hate that broadcast crap. Why the heck thought some folks that when going into deep idle it's a brilliant concept to switch off the last device which brings the cpu back from that state? ] Thanks to Christian for providing all the valuable debug information! Reported-and-tested-by: Christian Hoffmann Cc: John Stultz Link: http://lkml.kernel.org/r/%3Calpine.LFD.2.02.1105161105170.3078%40ionos%3E Cc: stable@kernel.org Signed-off-by: Thomas Gleixner --- kernel/time/tick-broadcast.c | 12 +++++++++++- 1 file changed, 11 insertions(+), 1 deletion(-) (limited to 'kernel') diff --git a/kernel/time/tick-broadcast.c b/kernel/time/tick-broadcast.c index da800ff..723c763 100644 --- a/kernel/time/tick-broadcast.c +++ b/kernel/time/tick-broadcast.c @@ -522,10 +522,11 @@ static void tick_broadcast_init_next_event(struct cpumask *mask, */ void tick_broadcast_setup_oneshot(struct clock_event_device *bc) { + int cpu = smp_processor_id(); + /* Set it up only once ! */ if (bc->event_handler != tick_handle_oneshot_broadcast) { int was_periodic = bc->mode == CLOCK_EVT_MODE_PERIODIC; - int cpu = smp_processor_id(); bc->event_handler = tick_handle_oneshot_broadcast; clockevents_set_mode(bc, CLOCK_EVT_MODE_ONESHOT); @@ -551,6 +552,15 @@ void tick_broadcast_setup_oneshot(struct clock_event_device *bc) tick_broadcast_set_event(tick_next_period, 1); } else bc->next_event.tv64 = KTIME_MAX; + } else { + /* + * The first cpu which switches to oneshot mode sets + * the bit for all other cpus which are in the general + * (periodic) broadcast mask. So the bit is set and + * would prevent the first broadcast enter after this + * to program the bc device. + */ + tick_broadcast_clear_oneshot(cpu); } } -- cgit v1.1 From 3c431936087e93d2219a184a8e19eaa68077e379 Mon Sep 17 00:00:00 2001 From: MyungJoo Ham Date: Fri, 22 Apr 2011 22:00:54 +0200 Subject: PM / Suspend: Do not ignore error codes returned by suspend_enter() The current implementation of suspend-to-RAM returns 0 if there is an error from suspend_enter(), because suspend_devices_and_enter() ignores the return value from suspend_enter(). This patch addresses this issue and properly keep the error return from suspend_enter() and let suspend_devices_and_enter relay the error return. Signed-off-by: MyungJoo Ham Signed-off-by: Kyungmin Park Signed-off-by: Rafael J. Wysocki --- kernel/power/suspend.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'kernel') diff --git a/kernel/power/suspend.c b/kernel/power/suspend.c index 6275970..fa9fabd 100644 --- a/kernel/power/suspend.c +++ b/kernel/power/suspend.c @@ -226,7 +226,7 @@ int suspend_devices_and_enter(suspend_state_t state) if (suspend_test(TEST_DEVICES)) goto Recover_platform; - suspend_enter(state); + error = suspend_enter(state); Resume_devices: suspend_test_start(); -- cgit v1.1 From ee940d8dccd899aa1777ea84da3d9cd04b1d2e8e Mon Sep 17 00:00:00 2001 From: Mike Frysinger Date: Mon, 25 Apr 2011 12:33:15 +0200 Subject: Freezer: Use SMP barriers The freezer processes are dealing with multiple threads running simultaneously, and on a UP system, the memory reads/writes do not need barriers to keep things in sync. These are only needed on SMP systems, so use SMP barriers instead. Signed-off-by: Mike Frysinger Acked-by: Pavel Machek Signed-off-by: Rafael J. Wysocki --- kernel/freezer.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) (limited to 'kernel') diff --git a/kernel/freezer.c b/kernel/freezer.c index 66ecd2e..7b01de98 100644 --- a/kernel/freezer.c +++ b/kernel/freezer.c @@ -17,7 +17,7 @@ static inline void frozen_process(void) { if (!unlikely(current->flags & PF_NOFREEZE)) { current->flags |= PF_FROZEN; - wmb(); + smp_wmb(); } clear_freeze_flag(current); } @@ -93,7 +93,7 @@ bool freeze_task(struct task_struct *p, bool sig_only) * the task as frozen and next clears its TIF_FREEZE. */ if (!freezing(p)) { - rmb(); + smp_rmb(); if (frozen(p)) return false; -- cgit v1.1 From a144c6a6c924aa1da04dd77fb84b89927354fdff Mon Sep 17 00:00:00 2001 From: "Rafael J. Wysocki" Date: Fri, 6 May 2011 20:09:42 +0200 Subject: PM: Print a warning if firmware is requested when tasks are frozen Some drivers erroneously use request_firmware() from their ->resume() (or ->thaw(), or ->restore()) callbacks, which is not going to work unless the firmware has been built in. This causes system resume to stall until the firmware-loading timeout expires, which makes users think that the resume has failed and reboot their machines unnecessarily. For this reason, make _request_firmware() print a warning and return immediately with error code if it has been called when tasks are frozen and it's impossible to start any new usermode helpers. Signed-off-by: Rafael J. Wysocki Acked-by: Greg Kroah-Hartman Reviewed-by: Valdis Kletnieks --- kernel/kmod.c | 9 +++++++++ 1 file changed, 9 insertions(+) (limited to 'kernel') diff --git a/kernel/kmod.c b/kernel/kmod.c index 9cd0591..9ab513b 100644 --- a/kernel/kmod.c +++ b/kernel/kmod.c @@ -301,6 +301,15 @@ void usermodehelper_enable(void) usermodehelper_disabled = 0; } +/** + * usermodehelper_is_disabled - check if new helpers are allowed to be started + */ +bool usermodehelper_is_disabled(void) +{ + return usermodehelper_disabled; +} +EXPORT_SYMBOL_GPL(usermodehelper_is_disabled); + static void helper_lock(void) { atomic_inc(&running_helpers); -- cgit v1.1 From 13d53f8775c6a00b070a3eef6833795412eb7fcd Mon Sep 17 00:00:00 2001 From: Kay Sievers Date: Tue, 10 May 2011 21:27:34 +0200 Subject: kmod: always provide usermodehelper_disable() We need to prevent kernel-forked processes during system poweroff. Such processes try to access the filesystem whose disks we are trying to shutdown at the same time. This causes delays and exceptions in the storage drivers. A follow-up patch will add these calls and need usermodehelper_disable() also on systems without suspend support. Signed-off-by: Kay Sievers Signed-off-by: Rafael J. Wysocki --- kernel/kmod.c | 7 ------- 1 file changed, 7 deletions(-) (limited to 'kernel') diff --git a/kernel/kmod.c b/kernel/kmod.c index 9ab513b..5ae0ff3 100644 --- a/kernel/kmod.c +++ b/kernel/kmod.c @@ -245,7 +245,6 @@ static void __call_usermodehelper(struct work_struct *work) } } -#ifdef CONFIG_PM_SLEEP /* * If set, call_usermodehelper_exec() will exit immediately returning -EBUSY * (used for preventing user land processes from being created after the user @@ -321,12 +320,6 @@ static void helper_unlock(void) if (atomic_dec_and_test(&running_helpers)) wake_up(&running_helpers_waitq); } -#else /* CONFIG_PM_SLEEP */ -#define usermodehelper_disabled 0 - -static inline void helper_lock(void) {} -static inline void helper_unlock(void) {} -#endif /* CONFIG_PM_SLEEP */ /** * call_usermodehelper_setup - prepare to call a usermode helper -- cgit v1.1 From ddeb648708108091a641adad0a438ec4fd8bf190 Mon Sep 17 00:00:00 2001 From: "Rafael J. Wysocki" Date: Sun, 15 May 2011 11:38:48 +0200 Subject: PM / Hibernate: Add sysfs knob to control size of memory for drivers Martin reports that on his system hibernation occasionally fails due to the lack of memory, because the radeon driver apparently allocates too much of it during the device freeze stage. It turns out that the amount of memory allocated by radeon during hibernation (and presumably during system suspend too) depends on the utilization of the GPU (e.g. hibernating while there are two KDE 4 sessions with compositing enabled causes radeon to allocate more memory than for one KDE 4 session). In principle it should be possible to use image_size to make the memory preallocation mechanism free enough memory for the radeon driver, but in practice it is not easy to guess the right value because of the way the preallocation code uses image_size. For this reason, it seems reasonable to allow users to control the amount of memory reserved for driver allocations made after the hibernate preallocation, which currently is constant and amounts to 1 MB. Introduce a new sysfs file, /sys/power/reserved_size, whose value will be used as the amount of memory to reserve for the post-preallocation reservations made by device drivers, in bytes. For backwards compatibility, set its default (and initial) value to the currently used number (1 MB). References: https://bugzilla.kernel.org/show_bug.cgi?id=34102 Reported-and-tested-by: Martin Steigerwald Signed-off-by: Rafael J. Wysocki --- kernel/power/hibernate.c | 23 +++++++++++++++++++++++ kernel/power/main.c | 1 + kernel/power/power.h | 4 ++++ kernel/power/snapshot.c | 25 ++++++++++++++++++++----- 4 files changed, 48 insertions(+), 5 deletions(-) (limited to 'kernel') diff --git a/kernel/power/hibernate.c b/kernel/power/hibernate.c index 50aae66..4317213 100644 --- a/kernel/power/hibernate.c +++ b/kernel/power/hibernate.c @@ -982,10 +982,33 @@ static ssize_t image_size_store(struct kobject *kobj, struct kobj_attribute *att power_attr(image_size); +static ssize_t reserved_size_show(struct kobject *kobj, + struct kobj_attribute *attr, char *buf) +{ + return sprintf(buf, "%lu\n", reserved_size); +} + +static ssize_t reserved_size_store(struct kobject *kobj, + struct kobj_attribute *attr, + const char *buf, size_t n) +{ + unsigned long size; + + if (sscanf(buf, "%lu", &size) == 1) { + reserved_size = size; + return n; + } + + return -EINVAL; +} + +power_attr(reserved_size); + static struct attribute * g[] = { &disk_attr.attr, &resume_attr.attr, &image_size_attr.attr, + &reserved_size_attr.attr, NULL, }; diff --git a/kernel/power/main.c b/kernel/power/main.c index de9aef8..2981af4 100644 --- a/kernel/power/main.c +++ b/kernel/power/main.c @@ -337,6 +337,7 @@ static int __init pm_init(void) if (error) return error; hibernate_image_size_init(); + hibernate_reserved_size_init(); power_kobj = kobject_create_and_add("power", NULL); if (!power_kobj) return -ENOMEM; diff --git a/kernel/power/power.h b/kernel/power/power.h index 03634be..9a00a0a 100644 --- a/kernel/power/power.h +++ b/kernel/power/power.h @@ -15,6 +15,7 @@ struct swsusp_info { #ifdef CONFIG_HIBERNATION /* kernel/power/snapshot.c */ +extern void __init hibernate_reserved_size_init(void); extern void __init hibernate_image_size_init(void); #ifdef CONFIG_ARCH_HIBERNATION_HEADER @@ -55,6 +56,7 @@ extern int hibernation_platform_enter(void); #else /* !CONFIG_HIBERNATION */ +static inline void hibernate_reserved_size_init(void) {} static inline void hibernate_image_size_init(void) {} #endif /* !CONFIG_HIBERNATION */ @@ -72,6 +74,8 @@ static struct kobj_attribute _name##_attr = { \ /* Preferred image size in bytes (default 500 MB) */ extern unsigned long image_size; +/* Size of memory reserved for drivers (default SPARE_PAGES x PAGE_SIZE) */ +extern unsigned long reserved_size; extern int in_suspend; extern dev_t swsusp_resume_device; extern sector_t swsusp_resume_block; diff --git a/kernel/power/snapshot.c b/kernel/power/snapshot.c index ca0aacc..d69e332 100644 --- a/kernel/power/snapshot.c +++ b/kernel/power/snapshot.c @@ -41,6 +41,18 @@ static void swsusp_set_page_forbidden(struct page *); static void swsusp_unset_page_forbidden(struct page *); /* + * Number of bytes to reserve for memory allocations made by device drivers + * from their ->freeze() and ->freeze_noirq() callbacks so that they don't + * cause image creation to fail (tunable via /sys/power/reserved_size). + */ +unsigned long reserved_size; + +void __init hibernate_reserved_size_init(void) +{ + reserved_size = SPARE_PAGES * PAGE_SIZE; +} + +/* * Preferred image size in bytes (tunable via /sys/power/image_size). * When it is set to N, the image creating code will do its best to * ensure the image size will not exceed N bytes, but if that is @@ -1263,11 +1275,13 @@ static unsigned long minimum_image_size(unsigned long saveable) * frame in use. We also need a number of page frames to be free during * hibernation for allocations made while saving the image and for device * drivers, in case they need to allocate memory from their hibernation - * callbacks (these two numbers are given by PAGES_FOR_IO and SPARE_PAGES, - * respectively, both of which are rough estimates). To make this happen, we - * compute the total number of available page frames and allocate at least + * callbacks (these two numbers are given by PAGES_FOR_IO (which is a rough + * estimate) and reserverd_size divided by PAGE_SIZE (which is tunable through + * /sys/power/reserved_size, respectively). To make this happen, we compute the + * total number of available page frames and allocate at least * - * ([page frames total] + PAGES_FOR_IO + [metadata pages]) / 2 + 2 * SPARE_PAGES + * ([page frames total] + PAGES_FOR_IO + [metadata pages]) / 2 + * + 2 * DIV_ROUND_UP(reserved_size, PAGE_SIZE) * * of them, which corresponds to the maximum size of a hibernation image. * @@ -1322,7 +1336,8 @@ int hibernate_preallocate_memory(void) count -= totalreserve_pages; /* Compute the maximum number of saveable pages to leave in memory. */ - max_size = (count - (size + PAGES_FOR_IO)) / 2 - 2 * SPARE_PAGES; + max_size = (count - (size + PAGES_FOR_IO)) / 2 + - 2 * DIV_ROUND_UP(reserved_size, PAGE_SIZE); /* Compute the desired number of image pages specified by image_size. */ size = DIV_ROUND_UP(image_size, PAGE_SIZE); if (size > max_size) -- cgit v1.1 From 1c1be3a949a61427a962771c85a347c822aeb991 Mon Sep 17 00:00:00 2001 From: "Rafael J. Wysocki" Date: Sun, 15 May 2011 11:39:48 +0200 Subject: Revert "PM / Hibernate: Reduce autotuned default image size" This reverts commit bea3864fb627d110933cfb8babe048b63c4fc76e (PM / Hibernate: Reduce autotuned default image size), because users are now able to resolve the issue this commit was supposed to address in a different way (i.e. by using the new /sys/power/reserved_size interface). Signed-off-by: Rafael J. Wysocki --- kernel/power/snapshot.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) (limited to 'kernel') diff --git a/kernel/power/snapshot.c b/kernel/power/snapshot.c index d69e332..ace5588 100644 --- a/kernel/power/snapshot.c +++ b/kernel/power/snapshot.c @@ -54,15 +54,15 @@ void __init hibernate_reserved_size_init(void) /* * Preferred image size in bytes (tunable via /sys/power/image_size). - * When it is set to N, the image creating code will do its best to - * ensure the image size will not exceed N bytes, but if that is - * impossible, it will try to create the smallest image possible. + * When it is set to N, swsusp will do its best to ensure the image + * size will not exceed N bytes, but if that is impossible, it will + * try to create the smallest image possible. */ unsigned long image_size; void __init hibernate_image_size_init(void) { - image_size = (totalram_pages / 3) * PAGE_SIZE; + image_size = ((totalram_pages * 2) / 5) * PAGE_SIZE; } /* List of PBEs needed for restoring the pages that were allocated before -- cgit v1.1 From c650da23d59d2c82307380414606774c6d49b8bd Mon Sep 17 00:00:00 2001 From: "Rafael J. Wysocki" Date: Tue, 17 May 2011 23:25:10 +0200 Subject: PM: Remove CONFIG_PM_VERBOSE Now that we have CONFIG_DYNAMIC_DEBUG there is no need for yet another flag causing dev_dbg() and pr_debug() statements in the core PM code to produce output. Moreover, CONFIG_PM_VERBOSE causes so much output to be generated that it's not really useful and almost no one sets it. References: https://bugzilla.kernel.org/show_bug.cgi?id=23182 Signed-off-by: Rafael J. Wysocki --- kernel/power/Kconfig | 6 ------ 1 file changed, 6 deletions(-) (limited to 'kernel') diff --git a/kernel/power/Kconfig b/kernel/power/Kconfig index d74ad4a..87f4d24 100644 --- a/kernel/power/Kconfig +++ b/kernel/power/Kconfig @@ -125,12 +125,6 @@ config PM_DEBUG code. This is helpful when debugging and reporting PM bugs, like suspend support. -config PM_VERBOSE - bool "Verbose Power Management debugging" - depends on PM_DEBUG - ---help--- - This option enables verbose messages from the Power Management code. - config PM_ADVANCED_DEBUG bool "Extra PM attributes in sysfs for low-level debugging/testing" depends on PM_DEBUG -- cgit v1.1 From 91e7c75ba93c48a82670d630b9daac92ff70095d Mon Sep 17 00:00:00 2001 From: "Rafael J. Wysocki" Date: Tue, 17 May 2011 23:26:00 +0200 Subject: PM: Allow drivers to allocate memory from .prepare() callbacks safely If device drivers allocate substantial amounts of memory (above 1 MB) in their hibernate .freeze() callbacks (or in their legacy suspend callbcks during hibernation), the subsequent creation of hibernate image may fail due to the lack of memory. This is the case, because the drivers' .freeze() callbacks are executed after the hibernate memory preallocation has been carried out and the preallocated amount of memory may be too small to cover the new driver allocations. Unfortunately, the drivers' .prepare() callbacks also are executed after the hibernate memory preallocation has completed, so they are not suitable for allocating additional memory either. Thus the only way a driver can safely allocate memory during hibernation is to use a hibernate/suspend notifier. However, the notifiers are called before the freezing of user space and the drivers wanting to use them for allocating additional memory may not know how much memory needs to be allocated at that point. To let device drivers overcome this difficulty rework the hibernation sequence so that the memory preallocation is carried out after the drivers' .prepare() callbacks have been executed, so that the .prepare() callbacks can be used for allocating additional memory to be used by the drivers' .freeze() callbacks. Update documentation to match the new behavior of the code. Signed-off-by: Rafael J. Wysocki --- kernel/power/hibernate.c | 17 +++++++++++++---- 1 file changed, 13 insertions(+), 4 deletions(-) (limited to 'kernel') diff --git a/kernel/power/hibernate.c b/kernel/power/hibernate.c index 95a2ac4..f9bec56 100644 --- a/kernel/power/hibernate.c +++ b/kernel/power/hibernate.c @@ -327,20 +327,25 @@ static int create_image(int platform_mode) int hibernation_snapshot(int platform_mode) { + pm_message_t msg = PMSG_RECOVER; int error; error = platform_begin(platform_mode); if (error) goto Close; + error = dpm_prepare(PMSG_FREEZE); + if (error) + goto Complete_devices; + /* Preallocate image memory before shutting down devices. */ error = hibernate_preallocate_memory(); if (error) - goto Close; + goto Complete_devices; suspend_console(); pm_restrict_gfp_mask(); - error = dpm_suspend_start(PMSG_FREEZE); + error = dpm_suspend(PMSG_FREEZE); if (error) goto Recover_platform; @@ -358,13 +363,17 @@ int hibernation_snapshot(int platform_mode) if (error || !in_suspend) swsusp_free(); - dpm_resume_end(in_suspend ? - (error ? PMSG_RECOVER : PMSG_THAW) : PMSG_RESTORE); + msg = in_suspend ? (error ? PMSG_RECOVER : PMSG_THAW) : PMSG_RESTORE; + dpm_resume(msg); if (error || !in_suspend) pm_restore_gfp_mask(); resume_console(); + + Complete_devices: + dpm_complete(msg); + Close: platform_end(platform_mode); return error; -- cgit v1.1 From fe0514348452f5b0ad7e842b0d71b8322b1297de Mon Sep 17 00:00:00 2001 From: Thomas Gleixner Date: Wed, 18 May 2011 12:53:03 +0200 Subject: genirq: Remove pointless ifdefs kernel/irq/ is only built when CONFIG_GENERIC_HARDIRQS=y. So making code inside of kernel/irq/ conditional on CONFIG_GENERIC_HARDIRQS is pointless. Signed-off-by: Thomas Gleixner --- kernel/irq/irqdesc.c | 4 +--- 1 file changed, 1 insertion(+), 3 deletions(-) (limited to 'kernel') diff --git a/kernel/irq/irqdesc.c b/kernel/irq/irqdesc.c index 2c039c9..e07b975 100644 --- a/kernel/irq/irqdesc.c +++ b/kernel/irq/irqdesc.c @@ -22,7 +22,7 @@ */ static struct lock_class_key irq_desc_lock_class; -#if defined(CONFIG_SMP) && defined(CONFIG_GENERIC_HARDIRQS) +#if defined(CONFIG_SMP) static void __init init_irq_default_affinity(void) { alloc_cpumask_var(&irq_default_affinity, GFP_NOWAIT); @@ -430,7 +430,6 @@ unsigned int kstat_irqs_cpu(unsigned int irq, int cpu) *per_cpu_ptr(desc->kstat_irqs, cpu) : 0; } -#ifdef CONFIG_GENERIC_HARDIRQS unsigned int kstat_irqs(unsigned int irq) { struct irq_desc *desc = irq_to_desc(irq); @@ -443,4 +442,3 @@ unsigned int kstat_irqs(unsigned int irq) sum += *per_cpu_ptr(desc->kstat_irqs, cpu); return sum; } -#endif /* CONFIG_GENERIC_HARDIRQS */ -- cgit v1.1 From fe12bc2c996d3e492b2920e32ac79f7bbae3e15d Mon Sep 17 00:00:00 2001 From: Thomas Gleixner Date: Wed, 18 May 2011 12:48:00 +0200 Subject: genirq: Uninline and sanity check generic_handle_irq() generic_handle_irq() is missing a NULL pointer check for the result of irq_to_desc. This was a not a big problem, but we want to expose it to drivers, so we better have sanity checks in place. Add a return value as well, which indicates that the irq number was valid and the handler was invoked. Based on the pure code move from Jonathan Cameron. Signed-off-by: Thomas Gleixner Cc: Jonathan Cameron --- kernel/irq/irqdesc.c | 15 +++++++++++++++ 1 file changed, 15 insertions(+) (limited to 'kernel') diff --git a/kernel/irq/irqdesc.c b/kernel/irq/irqdesc.c index e07b975..9f65b02 100644 --- a/kernel/irq/irqdesc.c +++ b/kernel/irq/irqdesc.c @@ -290,6 +290,21 @@ static int irq_expand_nr_irqs(unsigned int nr) #endif /* !CONFIG_SPARSE_IRQ */ +/** + * generic_handle_irq - Invoke the handler for a particular irq + * @irq: The irq number to handle + * + */ +int generic_handle_irq(unsigned int irq) +{ + struct irq_desc *desc = irq_to_desc(irq); + + if (!desc) + return -EINVAL; + generic_handle_irq_desc(irq, desc); + return 0; +} + /* Dynamic interrupt handling */ /** -- cgit v1.1 From edf76f8307c350bcb81f0c760118a991b3e62956 Mon Sep 17 00:00:00 2001 From: Jonathan Cameron Date: Wed, 18 May 2011 10:39:04 +0100 Subject: irq: Export functions to allow modular irq drivers Export handle_simple_irq, irq_modify_status, irq_alloc_descs, irq_free_descs and generic_handle_irq to allow their usage in modules. First user is IIO, which wants to be built modular, but needs to be able to create irq chips, allocate and configure interrupt descriptors and handle demultiplexing interrupts. [ tglx: Moved the uninlinig of generic_handle_irq to a separate patch ] Signed-off-by: Jonathan Cameron Link: http://lkml.kernel.org/r/%3C1305711544-505-1-git-send-email-jic23%40cam.ac.uk%3E Signed-off-by: Thomas Gleixner --- kernel/irq/chip.c | 2 ++ kernel/irq/irqdesc.c | 3 +++ 2 files changed, 5 insertions(+) (limited to 'kernel') diff --git a/kernel/irq/chip.c b/kernel/irq/chip.c index 52d856d..d5a3009 100644 --- a/kernel/irq/chip.c +++ b/kernel/irq/chip.c @@ -310,6 +310,7 @@ handle_simple_irq(unsigned int irq, struct irq_desc *desc) out_unlock: raw_spin_unlock(&desc->lock); } +EXPORT_SYMBOL_GPL(handle_simple_irq); /** * handle_level_irq - Level type irq handler @@ -613,6 +614,7 @@ void irq_modify_status(unsigned int irq, unsigned long clr, unsigned long set) irq_put_desc_unlock(desc, flags); } +EXPORT_SYMBOL_GPL(irq_modify_status); /** * irq_cpu_online - Invoke all irq_cpu_online functions. diff --git a/kernel/irq/irqdesc.c b/kernel/irq/irqdesc.c index 9f65b02..886e803 100644 --- a/kernel/irq/irqdesc.c +++ b/kernel/irq/irqdesc.c @@ -304,6 +304,7 @@ int generic_handle_irq(unsigned int irq) generic_handle_irq_desc(irq, desc); return 0; } +EXPORT_SYMBOL_GPL(generic_handle_irq); /* Dynamic interrupt handling */ @@ -326,6 +327,7 @@ void irq_free_descs(unsigned int from, unsigned int cnt) bitmap_clear(allocated_irqs, from, cnt); mutex_unlock(&sparse_irq_lock); } +EXPORT_SYMBOL_GPL(irq_free_descs); /** * irq_alloc_descs - allocate and initialize a range of irq descriptors @@ -366,6 +368,7 @@ err: mutex_unlock(&sparse_irq_lock); return ret; } +EXPORT_SYMBOL_GPL(irq_alloc_descs); /** * irq_reserve_irqs - mark irqs allocated -- cgit v1.1 From b448c4e3ae6d20108dba1d7833f2c0d3dbad87ce Mon Sep 17 00:00:00 2001 From: Steven Rostedt Date: Fri, 29 Apr 2011 15:12:32 -0400 Subject: ftrace: Replace FTRACE_FL_NOTRACE flag with a hash of ignored functions To prepare for the accounting system that will allow multiple users of the function tracer, having the FTRACE_FL_NOTRACE as a flag in the dyn_trace record does not make sense. All ftrace_ops will soon have a hash of functions they should trace and not trace. By making a global hash of functions not to trace makes this easier for the transition. Signed-off-by: Steven Rostedt --- kernel/trace/ftrace.c | 176 ++++++++++++++++++++++++++++++++++++++++++-------- 1 file changed, 150 insertions(+), 26 deletions(-) (limited to 'kernel') diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c index d340634..04c002a 100644 --- a/kernel/trace/ftrace.c +++ b/kernel/trace/ftrace.c @@ -57,6 +57,7 @@ /* hash bits for specific function selection */ #define FTRACE_HASH_BITS 7 #define FTRACE_FUNC_HASHSIZE (1 << FTRACE_HASH_BITS) +#define FTRACE_HASH_MAX_BITS 10 /* ftrace_enabled is a method to turn ftrace on or off */ int ftrace_enabled __read_mostly; @@ -865,6 +866,22 @@ enum { FTRACE_START_FUNC_RET = (1 << 3), FTRACE_STOP_FUNC_RET = (1 << 4), }; +struct ftrace_func_entry { + struct hlist_node hlist; + unsigned long ip; +}; + +struct ftrace_hash { + unsigned long size_bits; + struct hlist_head *buckets; + unsigned long count; +}; + +static struct hlist_head notrace_buckets[1 << FTRACE_HASH_MAX_BITS]; +static struct ftrace_hash notrace_hash = { + .size_bits = FTRACE_HASH_MAX_BITS, + .buckets = notrace_buckets, +}; static int ftrace_filtered; @@ -889,6 +906,79 @@ static struct ftrace_page *ftrace_pages; static struct dyn_ftrace *ftrace_free_records; +static struct ftrace_func_entry * +ftrace_lookup_ip(struct ftrace_hash *hash, unsigned long ip) +{ + unsigned long key; + struct ftrace_func_entry *entry; + struct hlist_head *hhd; + struct hlist_node *n; + + if (!hash->count) + return NULL; + + if (hash->size_bits > 0) + key = hash_long(ip, hash->size_bits); + else + key = 0; + + hhd = &hash->buckets[key]; + + hlist_for_each_entry_rcu(entry, n, hhd, hlist) { + if (entry->ip == ip) + return entry; + } + return NULL; +} + +static int add_hash_entry(struct ftrace_hash *hash, unsigned long ip) +{ + struct ftrace_func_entry *entry; + struct hlist_head *hhd; + unsigned long key; + + entry = kmalloc(sizeof(*entry), GFP_KERNEL); + if (!entry) + return -ENOMEM; + + if (hash->size_bits) + key = hash_long(ip, hash->size_bits); + else + key = 0; + + entry->ip = ip; + hhd = &hash->buckets[key]; + hlist_add_head(&entry->hlist, hhd); + hash->count++; + + return 0; +} + +static void +remove_hash_entry(struct ftrace_hash *hash, + struct ftrace_func_entry *entry) +{ + hlist_del(&entry->hlist); + kfree(entry); + hash->count--; +} + +static void ftrace_hash_clear(struct ftrace_hash *hash) +{ + struct hlist_head *hhd; + struct hlist_node *tp, *tn; + struct ftrace_func_entry *entry; + int size = 1 << hash->size_bits; + int i; + + for (i = 0; i < size; i++) { + hhd = &hash->buckets[i]; + hlist_for_each_entry_safe(entry, tp, tn, hhd, hlist) + remove_hash_entry(hash, entry); + } + FTRACE_WARN_ON(hash->count); +} + /* * This is a double for. Do not use 'break' to break out of the loop, * you must use a goto. @@ -1032,7 +1122,7 @@ __ftrace_replace_code(struct dyn_ftrace *rec, int enable) * If we want to enable it and filtering is on, enable it only if * it's filtered */ - if (enable && !(rec->flags & FTRACE_FL_NOTRACE)) { + if (enable && !ftrace_lookup_ip(¬race_hash, rec->ip)) { if (!ftrace_filtered || (rec->flags & FTRACE_FL_FILTER)) flag = FTRACE_FL_ENABLED; } @@ -1465,7 +1555,7 @@ t_next(struct seq_file *m, void *v, loff_t *pos) !(rec->flags & FTRACE_FL_FILTER)) || ((iter->flags & FTRACE_ITER_NOTRACE) && - !(rec->flags & FTRACE_FL_NOTRACE))) { + !ftrace_lookup_ip(¬race_hash, rec->ip))) { rec = NULL; goto retry; } @@ -1609,14 +1699,15 @@ static void ftrace_filter_reset(int enable) { struct ftrace_page *pg; struct dyn_ftrace *rec; - unsigned long type = enable ? FTRACE_FL_FILTER : FTRACE_FL_NOTRACE; mutex_lock(&ftrace_lock); - if (enable) + if (enable) { ftrace_filtered = 0; - do_for_each_ftrace_rec(pg, rec) { - rec->flags &= ~type; - } while_for_each_ftrace_rec(); + do_for_each_ftrace_rec(pg, rec) { + rec->flags &= ~FTRACE_FL_FILTER; + } while_for_each_ftrace_rec(); + } else + ftrace_hash_clear(¬race_hash); mutex_unlock(&ftrace_lock); } @@ -1716,13 +1807,36 @@ static int ftrace_match(char *str, char *regex, int len, int type) return matched; } -static void -update_record(struct dyn_ftrace *rec, unsigned long flag, int not) +static int +update_record(struct dyn_ftrace *rec, int enable, int not) { - if (not) - rec->flags &= ~flag; - else - rec->flags |= flag; + struct ftrace_func_entry *entry; + struct ftrace_hash *hash = ¬race_hash; + int ret = 0; + + if (enable) { + if (not) + rec->flags &= ~FTRACE_FL_FILTER; + else + rec->flags |= FTRACE_FL_FILTER; + } else { + if (not) { + /* Do nothing if it doesn't exist */ + entry = ftrace_lookup_ip(hash, rec->ip); + if (!entry) + return 0; + + remove_hash_entry(hash, entry); + } else { + /* Do nothing if it exists */ + entry = ftrace_lookup_ip(hash, rec->ip); + if (entry) + return 0; + + ret = add_hash_entry(hash, rec->ip); + } + } + return ret; } static int @@ -1754,16 +1868,14 @@ static int match_records(char *buff, int len, char *mod, int enable, int not) struct dyn_ftrace *rec; int type = MATCH_FULL; char *search = buff; - unsigned long flag; int found = 0; + int ret; if (len) { type = filter_parse_regex(buff, len, &search, ¬); search_len = strlen(search); } - flag = enable ? FTRACE_FL_FILTER : FTRACE_FL_NOTRACE; - mutex_lock(&ftrace_lock); if (unlikely(ftrace_disabled)) @@ -1772,7 +1884,11 @@ static int match_records(char *buff, int len, char *mod, int enable, int not) do_for_each_ftrace_rec(pg, rec) { if (ftrace_match_record(rec, mod, search, search_len, type)) { - update_record(rec, flag, not); + ret = update_record(rec, enable, not); + if (ret < 0) { + found = ret; + goto out_unlock; + } found = 1; } /* @@ -1821,6 +1937,7 @@ static int ftrace_mod_callback(char *func, char *cmd, char *param, int enable) { char *mod; + int ret = -EINVAL; /* * cmd == 'mod' because we only registered this func @@ -1832,15 +1949,19 @@ ftrace_mod_callback(char *func, char *cmd, char *param, int enable) /* we must have a module name */ if (!param) - return -EINVAL; + return ret; mod = strsep(¶m, ":"); if (!strlen(mod)) - return -EINVAL; + return ret; - if (ftrace_match_module_records(func, mod, enable)) - return 0; - return -EINVAL; + ret = ftrace_match_module_records(func, mod, enable); + if (!ret) + ret = -EINVAL; + if (ret < 0) + return ret; + + return 0; } static struct ftrace_func_command ftrace_mod_cmd = { @@ -2132,14 +2253,17 @@ static int ftrace_process_regex(char *buff, int len, int enable) { char *func, *command, *next = buff; struct ftrace_func_command *p; - int ret = -EINVAL; + int ret; func = strsep(&next, ":"); if (!next) { - if (ftrace_match_records(func, len, enable)) - return 0; - return ret; + ret = ftrace_match_records(func, len, enable); + if (!ret) + ret = -EINVAL; + if (ret < 0) + return ret; + return 0; } /* command found */ -- cgit v1.1 From 1cf41dd79993389b012e4542ab502ce36ae7343f Mon Sep 17 00:00:00 2001 From: Steven Rostedt Date: Fri, 29 Apr 2011 20:59:51 -0400 Subject: ftrace: Use hash instead for FTRACE_FL_FILTER When multiple users are allowed to have their own set of functions to trace, having the FTRACE_FL_FILTER flag will not be enough to handle the accounting of those users. Each user will need their own set of functions. Replace the FTRACE_FL_FILTER with a filter_hash instead. This is temporary until the rest of the function filtering accounting gets in. Signed-off-by: Steven Rostedt --- kernel/trace/ftrace.c | 151 +++++++++++++++++++++++--------------------------- 1 file changed, 69 insertions(+), 82 deletions(-) (limited to 'kernel') diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c index 04c002a..222eca4 100644 --- a/kernel/trace/ftrace.c +++ b/kernel/trace/ftrace.c @@ -883,7 +883,11 @@ static struct ftrace_hash notrace_hash = { .buckets = notrace_buckets, }; -static int ftrace_filtered; +static struct hlist_head filter_buckets[1 << FTRACE_HASH_MAX_BITS]; +static struct ftrace_hash filter_hash = { + .size_bits = FTRACE_HASH_MAX_BITS, + .buckets = filter_buckets, +}; static struct dyn_ftrace *ftrace_new_addrs; @@ -1123,7 +1127,7 @@ __ftrace_replace_code(struct dyn_ftrace *rec, int enable) * it's filtered */ if (enable && !ftrace_lookup_ip(¬race_hash, rec->ip)) { - if (!ftrace_filtered || (rec->flags & FTRACE_FL_FILTER)) + if (!filter_hash.count || ftrace_lookup_ip(&filter_hash, rec->ip)) flag = FTRACE_FL_ENABLED; } @@ -1430,6 +1434,7 @@ struct ftrace_iterator { struct dyn_ftrace *func; struct ftrace_func_probe *probe; struct trace_parser parser; + struct ftrace_hash *hash; int hidx; int idx; unsigned flags; @@ -1552,7 +1557,7 @@ t_next(struct seq_file *m, void *v, loff_t *pos) if ((rec->flags & FTRACE_FL_FREE) || ((iter->flags & FTRACE_ITER_FILTER) && - !(rec->flags & FTRACE_FL_FILTER)) || + !(ftrace_lookup_ip(&filter_hash, rec->ip))) || ((iter->flags & FTRACE_ITER_NOTRACE) && !ftrace_lookup_ip(¬race_hash, rec->ip))) { @@ -1598,7 +1603,7 @@ static void *t_start(struct seq_file *m, loff_t *pos) * off, we can short cut and just print out that all * functions are enabled. */ - if (iter->flags & FTRACE_ITER_FILTER && !ftrace_filtered) { + if (iter->flags & FTRACE_ITER_FILTER && !filter_hash.count) { if (*pos > 0) return t_hash_start(m, pos); iter->flags |= FTRACE_ITER_PRINTALL; @@ -1695,24 +1700,16 @@ ftrace_avail_open(struct inode *inode, struct file *file) return ret; } -static void ftrace_filter_reset(int enable) +static void ftrace_filter_reset(struct ftrace_hash *hash) { - struct ftrace_page *pg; - struct dyn_ftrace *rec; - mutex_lock(&ftrace_lock); - if (enable) { - ftrace_filtered = 0; - do_for_each_ftrace_rec(pg, rec) { - rec->flags &= ~FTRACE_FL_FILTER; - } while_for_each_ftrace_rec(); - } else - ftrace_hash_clear(¬race_hash); + ftrace_hash_clear(hash); mutex_unlock(&ftrace_lock); } static int -ftrace_regex_open(struct inode *inode, struct file *file, int enable) +ftrace_regex_open(struct ftrace_hash *hash, int flag, + struct inode *inode, struct file *file) { struct ftrace_iterator *iter; int ret = 0; @@ -1729,15 +1726,16 @@ ftrace_regex_open(struct inode *inode, struct file *file, int enable) return -ENOMEM; } + iter->hash = hash; + mutex_lock(&ftrace_regex_lock); if ((file->f_mode & FMODE_WRITE) && (file->f_flags & O_TRUNC)) - ftrace_filter_reset(enable); + ftrace_filter_reset(hash); if (file->f_mode & FMODE_READ) { iter->pg = ftrace_pages_start; - iter->flags = enable ? FTRACE_ITER_FILTER : - FTRACE_ITER_NOTRACE; + iter->flags = flag; ret = seq_open(file, &show_ftrace_seq_ops); if (!ret) { @@ -1757,13 +1755,15 @@ ftrace_regex_open(struct inode *inode, struct file *file, int enable) static int ftrace_filter_open(struct inode *inode, struct file *file) { - return ftrace_regex_open(inode, file, 1); + return ftrace_regex_open(&filter_hash, FTRACE_ITER_FILTER, + inode, file); } static int ftrace_notrace_open(struct inode *inode, struct file *file) { - return ftrace_regex_open(inode, file, 0); + return ftrace_regex_open(¬race_hash, FTRACE_ITER_NOTRACE, + inode, file); } static loff_t @@ -1808,33 +1808,24 @@ static int ftrace_match(char *str, char *regex, int len, int type) } static int -update_record(struct dyn_ftrace *rec, int enable, int not) +enter_record(struct ftrace_hash *hash, struct dyn_ftrace *rec, int not) { struct ftrace_func_entry *entry; - struct ftrace_hash *hash = ¬race_hash; int ret = 0; - if (enable) { - if (not) - rec->flags &= ~FTRACE_FL_FILTER; - else - rec->flags |= FTRACE_FL_FILTER; - } else { - if (not) { - /* Do nothing if it doesn't exist */ - entry = ftrace_lookup_ip(hash, rec->ip); - if (!entry) - return 0; + entry = ftrace_lookup_ip(hash, rec->ip); + if (not) { + /* Do nothing if it doesn't exist */ + if (!entry) + return 0; - remove_hash_entry(hash, entry); - } else { - /* Do nothing if it exists */ - entry = ftrace_lookup_ip(hash, rec->ip); - if (entry) - return 0; + remove_hash_entry(hash, entry); + } else { + /* Do nothing if it exists */ + if (entry) + return 0; - ret = add_hash_entry(hash, rec->ip); - } + ret = add_hash_entry(hash, rec->ip); } return ret; } @@ -1861,7 +1852,9 @@ ftrace_match_record(struct dyn_ftrace *rec, char *mod, return ftrace_match(str, regex, len, type); } -static int match_records(char *buff, int len, char *mod, int enable, int not) +static int +match_records(struct ftrace_hash *hash, char *buff, + int len, char *mod, int not) { unsigned search_len = 0; struct ftrace_page *pg; @@ -1884,20 +1877,13 @@ static int match_records(char *buff, int len, char *mod, int enable, int not) do_for_each_ftrace_rec(pg, rec) { if (ftrace_match_record(rec, mod, search, search_len, type)) { - ret = update_record(rec, enable, not); + ret = enter_record(hash, rec, not); if (ret < 0) { found = ret; goto out_unlock; } found = 1; } - /* - * Only enable filtering if we have a function that - * is filtered on. - */ - if (enable && (rec->flags & FTRACE_FL_FILTER)) - ftrace_filtered = 1; - } while_for_each_ftrace_rec(); out_unlock: mutex_unlock(&ftrace_lock); @@ -1906,12 +1892,13 @@ static int match_records(char *buff, int len, char *mod, int enable, int not) } static int -ftrace_match_records(char *buff, int len, int enable) +ftrace_match_records(struct ftrace_hash *hash, char *buff, int len) { - return match_records(buff, len, NULL, enable, 0); + return match_records(hash, buff, len, NULL, 0); } -static int ftrace_match_module_records(char *buff, char *mod, int enable) +static int +ftrace_match_module_records(struct ftrace_hash *hash, char *buff, char *mod) { int not = 0; @@ -1925,7 +1912,7 @@ static int ftrace_match_module_records(char *buff, char *mod, int enable) not = 1; } - return match_records(buff, strlen(buff), mod, enable, not); + return match_records(hash, buff, strlen(buff), mod, not); } /* @@ -1936,6 +1923,7 @@ static int ftrace_match_module_records(char *buff, char *mod, int enable) static int ftrace_mod_callback(char *func, char *cmd, char *param, int enable) { + struct ftrace_hash *hash; char *mod; int ret = -EINVAL; @@ -1955,7 +1943,12 @@ ftrace_mod_callback(char *func, char *cmd, char *param, int enable) if (!strlen(mod)) return ret; - ret = ftrace_match_module_records(func, mod, enable); + if (enable) + hash = &filter_hash; + else + hash = ¬race_hash; + + ret = ftrace_match_module_records(hash, func, mod); if (!ret) ret = -EINVAL; if (ret < 0) @@ -2253,12 +2246,18 @@ static int ftrace_process_regex(char *buff, int len, int enable) { char *func, *command, *next = buff; struct ftrace_func_command *p; + struct ftrace_hash *hash; int ret; + if (enable) + hash = &filter_hash; + else + hash = ¬race_hash; + func = strsep(&next, ":"); if (!next) { - ret = ftrace_match_records(func, len, enable); + ret = ftrace_match_records(hash, func, len); if (!ret) ret = -EINVAL; if (ret < 0) @@ -2340,16 +2339,16 @@ ftrace_notrace_write(struct file *file, const char __user *ubuf, } static void -ftrace_set_regex(unsigned char *buf, int len, int reset, int enable) +ftrace_set_regex(struct ftrace_hash *hash, unsigned char *buf, int len, int reset) { if (unlikely(ftrace_disabled)) return; mutex_lock(&ftrace_regex_lock); if (reset) - ftrace_filter_reset(enable); + ftrace_filter_reset(hash); if (buf) - ftrace_match_records(buf, len, enable); + ftrace_match_records(hash, buf, len); mutex_unlock(&ftrace_regex_lock); } @@ -2364,7 +2363,7 @@ ftrace_set_regex(unsigned char *buf, int len, int reset, int enable) */ void ftrace_set_filter(unsigned char *buf, int len, int reset) { - ftrace_set_regex(buf, len, reset, 1); + ftrace_set_regex(&filter_hash, buf, len, reset); } /** @@ -2379,7 +2378,7 @@ void ftrace_set_filter(unsigned char *buf, int len, int reset) */ void ftrace_set_notrace(unsigned char *buf, int len, int reset) { - ftrace_set_regex(buf, len, reset, 0); + ftrace_set_regex(¬race_hash, buf, len, reset); } /* @@ -2431,22 +2430,22 @@ static void __init set_ftrace_early_graph(char *buf) } #endif /* CONFIG_FUNCTION_GRAPH_TRACER */ -static void __init set_ftrace_early_filter(char *buf, int enable) +static void __init set_ftrace_early_filter(struct ftrace_hash *hash, char *buf) { char *func; while (buf) { func = strsep(&buf, ","); - ftrace_set_regex(func, strlen(func), 0, enable); + ftrace_set_regex(hash, func, strlen(func), 0); } } static void __init set_ftrace_early_filters(void) { if (ftrace_filter_buf[0]) - set_ftrace_early_filter(ftrace_filter_buf, 1); + set_ftrace_early_filter(&filter_hash, ftrace_filter_buf); if (ftrace_notrace_buf[0]) - set_ftrace_early_filter(ftrace_notrace_buf, 0); + set_ftrace_early_filter(¬race_hash, ftrace_notrace_buf); #ifdef CONFIG_FUNCTION_GRAPH_TRACER if (ftrace_graph_buf[0]) set_ftrace_early_graph(ftrace_graph_buf); @@ -2454,7 +2453,7 @@ static void __init set_ftrace_early_filters(void) } static int -ftrace_regex_release(struct inode *inode, struct file *file, int enable) +ftrace_regex_release(struct inode *inode, struct file *file) { struct seq_file *m = (struct seq_file *)file->private_data; struct ftrace_iterator *iter; @@ -2471,7 +2470,7 @@ ftrace_regex_release(struct inode *inode, struct file *file, int enable) parser = &iter->parser; if (trace_parser_loaded(parser)) { parser->buffer[parser->idx] = 0; - ftrace_match_records(parser->buffer, parser->idx, enable); + ftrace_match_records(iter->hash, parser->buffer, parser->idx); } trace_parser_put(parser); @@ -2488,18 +2487,6 @@ ftrace_regex_release(struct inode *inode, struct file *file, int enable) return 0; } -static int -ftrace_filter_release(struct inode *inode, struct file *file) -{ - return ftrace_regex_release(inode, file, 1); -} - -static int -ftrace_notrace_release(struct inode *inode, struct file *file) -{ - return ftrace_regex_release(inode, file, 0); -} - static const struct file_operations ftrace_avail_fops = { .open = ftrace_avail_open, .read = seq_read, @@ -2512,7 +2499,7 @@ static const struct file_operations ftrace_filter_fops = { .read = seq_read, .write = ftrace_filter_write, .llseek = ftrace_regex_lseek, - .release = ftrace_filter_release, + .release = ftrace_regex_release, }; static const struct file_operations ftrace_notrace_fops = { @@ -2520,7 +2507,7 @@ static const struct file_operations ftrace_notrace_fops = { .read = seq_read, .write = ftrace_notrace_write, .llseek = ftrace_regex_lseek, - .release = ftrace_notrace_release, + .release = ftrace_regex_release, }; #ifdef CONFIG_FUNCTION_GRAPH_TRACER -- cgit v1.1 From f45948e898e7bc76a73a468796d2ce80dd040058 Mon Sep 17 00:00:00 2001 From: Steven Rostedt Date: Mon, 2 May 2011 12:29:25 -0400 Subject: ftrace: Create a global_ops to hold the filter and notrace hashes Combine the filter and notrace hashes to be accessed by a single entity, the global_ops. The global_ops is a ftrace_ops structure that is passed to different functions that can read or modify the filtering of the function tracer. The ftrace_ops structure was modified to hold a filter and notrace hashes so that later patches may allow each ftrace_ops to have its own set of rules to what functions may be filtered. Signed-off-by: Steven Rostedt --- kernel/trace/ftrace.c | 65 ++++++++++++++++++++++++++++++++++++--------------- 1 file changed, 46 insertions(+), 19 deletions(-) (limited to 'kernel') diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c index 222eca4..a517a6c 100644 --- a/kernel/trace/ftrace.c +++ b/kernel/trace/ftrace.c @@ -889,6 +889,12 @@ static struct ftrace_hash filter_hash = { .buckets = filter_buckets, }; +struct ftrace_ops global_ops = { + .func = ftrace_stub, + .notrace_hash = ¬race_hash, + .filter_hash = &filter_hash, +}; + static struct dyn_ftrace *ftrace_new_addrs; static DEFINE_MUTEX(ftrace_regex_lock); @@ -1112,6 +1118,7 @@ int ftrace_text_reserved(void *start, void *end) static int __ftrace_replace_code(struct dyn_ftrace *rec, int enable) { + struct ftrace_ops *ops = &global_ops; unsigned long ftrace_addr; unsigned long flag = 0UL; @@ -1126,8 +1133,9 @@ __ftrace_replace_code(struct dyn_ftrace *rec, int enable) * If we want to enable it and filtering is on, enable it only if * it's filtered */ - if (enable && !ftrace_lookup_ip(¬race_hash, rec->ip)) { - if (!filter_hash.count || ftrace_lookup_ip(&filter_hash, rec->ip)) + if (enable && !ftrace_lookup_ip(ops->notrace_hash, rec->ip)) { + if (!ops->filter_hash->count || + ftrace_lookup_ip(ops->filter_hash, rec->ip)) flag = FTRACE_FL_ENABLED; } @@ -1531,6 +1539,7 @@ static void * t_next(struct seq_file *m, void *v, loff_t *pos) { struct ftrace_iterator *iter = m->private; + struct ftrace_ops *ops = &global_ops; struct dyn_ftrace *rec = NULL; if (unlikely(ftrace_disabled)) @@ -1557,10 +1566,10 @@ t_next(struct seq_file *m, void *v, loff_t *pos) if ((rec->flags & FTRACE_FL_FREE) || ((iter->flags & FTRACE_ITER_FILTER) && - !(ftrace_lookup_ip(&filter_hash, rec->ip))) || + !(ftrace_lookup_ip(ops->filter_hash, rec->ip))) || ((iter->flags & FTRACE_ITER_NOTRACE) && - !ftrace_lookup_ip(¬race_hash, rec->ip))) { + !ftrace_lookup_ip(ops->notrace_hash, rec->ip))) { rec = NULL; goto retry; } @@ -1584,6 +1593,7 @@ static void reset_iter_read(struct ftrace_iterator *iter) static void *t_start(struct seq_file *m, loff_t *pos) { struct ftrace_iterator *iter = m->private; + struct ftrace_ops *ops = &global_ops; void *p = NULL; loff_t l; @@ -1603,7 +1613,7 @@ static void *t_start(struct seq_file *m, loff_t *pos) * off, we can short cut and just print out that all * functions are enabled. */ - if (iter->flags & FTRACE_ITER_FILTER && !filter_hash.count) { + if (iter->flags & FTRACE_ITER_FILTER && !ops->filter_hash->count) { if (*pos > 0) return t_hash_start(m, pos); iter->flags |= FTRACE_ITER_PRINTALL; @@ -1708,10 +1718,11 @@ static void ftrace_filter_reset(struct ftrace_hash *hash) } static int -ftrace_regex_open(struct ftrace_hash *hash, int flag, +ftrace_regex_open(struct ftrace_ops *ops, int flag, struct inode *inode, struct file *file) { struct ftrace_iterator *iter; + struct ftrace_hash *hash; int ret = 0; if (unlikely(ftrace_disabled)) @@ -1726,6 +1737,11 @@ ftrace_regex_open(struct ftrace_hash *hash, int flag, return -ENOMEM; } + if (flag & FTRACE_ITER_NOTRACE) + hash = ops->notrace_hash; + else + hash = ops->filter_hash; + iter->hash = hash; mutex_lock(&ftrace_regex_lock); @@ -1755,14 +1771,14 @@ ftrace_regex_open(struct ftrace_hash *hash, int flag, static int ftrace_filter_open(struct inode *inode, struct file *file) { - return ftrace_regex_open(&filter_hash, FTRACE_ITER_FILTER, + return ftrace_regex_open(&global_ops, FTRACE_ITER_FILTER, inode, file); } static int ftrace_notrace_open(struct inode *inode, struct file *file) { - return ftrace_regex_open(¬race_hash, FTRACE_ITER_NOTRACE, + return ftrace_regex_open(&global_ops, FTRACE_ITER_NOTRACE, inode, file); } @@ -1923,6 +1939,7 @@ ftrace_match_module_records(struct ftrace_hash *hash, char *buff, char *mod) static int ftrace_mod_callback(char *func, char *cmd, char *param, int enable) { + struct ftrace_ops *ops = &global_ops; struct ftrace_hash *hash; char *mod; int ret = -EINVAL; @@ -1944,9 +1961,9 @@ ftrace_mod_callback(char *func, char *cmd, char *param, int enable) return ret; if (enable) - hash = &filter_hash; + hash = ops->filter_hash; else - hash = ¬race_hash; + hash = ops->notrace_hash; ret = ftrace_match_module_records(hash, func, mod); if (!ret) @@ -2245,14 +2262,15 @@ int unregister_ftrace_command(struct ftrace_func_command *cmd) static int ftrace_process_regex(char *buff, int len, int enable) { char *func, *command, *next = buff; + struct ftrace_ops *ops = &global_ops; struct ftrace_func_command *p; struct ftrace_hash *hash; int ret; if (enable) - hash = &filter_hash; + hash = ops->filter_hash; else - hash = ¬race_hash; + hash = ops->notrace_hash; func = strsep(&next, ":"); @@ -2339,11 +2357,19 @@ ftrace_notrace_write(struct file *file, const char __user *ubuf, } static void -ftrace_set_regex(struct ftrace_hash *hash, unsigned char *buf, int len, int reset) +ftrace_set_regex(struct ftrace_ops *ops, unsigned char *buf, int len, + int reset, int enable) { + struct ftrace_hash *hash; + if (unlikely(ftrace_disabled)) return; + if (enable) + hash = ops->filter_hash; + else + hash = ops->notrace_hash; + mutex_lock(&ftrace_regex_lock); if (reset) ftrace_filter_reset(hash); @@ -2363,7 +2389,7 @@ ftrace_set_regex(struct ftrace_hash *hash, unsigned char *buf, int len, int rese */ void ftrace_set_filter(unsigned char *buf, int len, int reset) { - ftrace_set_regex(&filter_hash, buf, len, reset); + ftrace_set_regex(&global_ops, buf, len, reset, 1); } /** @@ -2378,7 +2404,7 @@ void ftrace_set_filter(unsigned char *buf, int len, int reset) */ void ftrace_set_notrace(unsigned char *buf, int len, int reset) { - ftrace_set_regex(¬race_hash, buf, len, reset); + ftrace_set_regex(&global_ops, buf, len, reset, 0); } /* @@ -2430,22 +2456,23 @@ static void __init set_ftrace_early_graph(char *buf) } #endif /* CONFIG_FUNCTION_GRAPH_TRACER */ -static void __init set_ftrace_early_filter(struct ftrace_hash *hash, char *buf) +static void __init +set_ftrace_early_filter(struct ftrace_ops *ops, char *buf, int enable) { char *func; while (buf) { func = strsep(&buf, ","); - ftrace_set_regex(hash, func, strlen(func), 0); + ftrace_set_regex(ops, func, strlen(func), 0, enable); } } static void __init set_ftrace_early_filters(void) { if (ftrace_filter_buf[0]) - set_ftrace_early_filter(&filter_hash, ftrace_filter_buf); + set_ftrace_early_filter(&global_ops, ftrace_filter_buf, 1); if (ftrace_notrace_buf[0]) - set_ftrace_early_filter(¬race_hash, ftrace_notrace_buf); + set_ftrace_early_filter(&global_ops, ftrace_notrace_buf, 0); #ifdef CONFIG_FUNCTION_GRAPH_TRACER if (ftrace_graph_buf[0]) set_ftrace_early_graph(ftrace_graph_buf); -- cgit v1.1 From 33dc9b1267d59cef46ff0bd6bc043190845dc919 Mon Sep 17 00:00:00 2001 From: Steven Rostedt Date: Mon, 2 May 2011 17:34:47 -0400 Subject: ftrace: Separate hash allocation and assignment When filtering, allocate a hash to insert the function records. After the filtering is complete, assign it to the ftrace_ops structure. This allows the ftrace_ops structure to have a much smaller array of hash buckets instead of wasting a lot of memory. A read only empty_hash is created to be the minimum size that any ftrace_ops can point to. When a new hash is created, it has the following steps: o Allocate a default hash. o Walk the function records assigning the filtered records to the hash o Allocate a new hash with the appropriate size buckets o Move the entries from the default hash to the new hash. Signed-off-by: Steven Rostedt --- kernel/trace/ftrace.c | 275 ++++++++++++++++++++++++++++++++++++++++++-------- 1 file changed, 233 insertions(+), 42 deletions(-) (limited to 'kernel') diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c index a517a6c..46f0826 100644 --- a/kernel/trace/ftrace.c +++ b/kernel/trace/ftrace.c @@ -57,7 +57,8 @@ /* hash bits for specific function selection */ #define FTRACE_HASH_BITS 7 #define FTRACE_FUNC_HASHSIZE (1 << FTRACE_HASH_BITS) -#define FTRACE_HASH_MAX_BITS 10 +#define FTRACE_HASH_DEFAULT_BITS 10 +#define FTRACE_HASH_MAX_BITS 12 /* ftrace_enabled is a method to turn ftrace on or off */ int ftrace_enabled __read_mostly; @@ -877,22 +878,22 @@ struct ftrace_hash { unsigned long count; }; -static struct hlist_head notrace_buckets[1 << FTRACE_HASH_MAX_BITS]; -static struct ftrace_hash notrace_hash = { - .size_bits = FTRACE_HASH_MAX_BITS, - .buckets = notrace_buckets, -}; - -static struct hlist_head filter_buckets[1 << FTRACE_HASH_MAX_BITS]; -static struct ftrace_hash filter_hash = { - .size_bits = FTRACE_HASH_MAX_BITS, - .buckets = filter_buckets, +/* + * We make these constant because no one should touch them, + * but they are used as the default "empty hash", to avoid allocating + * it all the time. These are in a read only section such that if + * anyone does try to modify it, it will cause an exception. + */ +static const struct hlist_head empty_buckets[1]; +static const struct ftrace_hash empty_hash = { + .buckets = (struct hlist_head *)empty_buckets, }; +#define EMPTY_HASH ((struct ftrace_hash *)&empty_hash) struct ftrace_ops global_ops = { .func = ftrace_stub, - .notrace_hash = ¬race_hash, - .filter_hash = &filter_hash, + .notrace_hash = EMPTY_HASH, + .filter_hash = EMPTY_HASH, }; static struct dyn_ftrace *ftrace_new_addrs; @@ -941,31 +942,38 @@ ftrace_lookup_ip(struct ftrace_hash *hash, unsigned long ip) return NULL; } -static int add_hash_entry(struct ftrace_hash *hash, unsigned long ip) +static void __add_hash_entry(struct ftrace_hash *hash, + struct ftrace_func_entry *entry) { - struct ftrace_func_entry *entry; struct hlist_head *hhd; unsigned long key; - entry = kmalloc(sizeof(*entry), GFP_KERNEL); - if (!entry) - return -ENOMEM; - if (hash->size_bits) - key = hash_long(ip, hash->size_bits); + key = hash_long(entry->ip, hash->size_bits); else key = 0; - entry->ip = ip; hhd = &hash->buckets[key]; hlist_add_head(&entry->hlist, hhd); hash->count++; +} + +static int add_hash_entry(struct ftrace_hash *hash, unsigned long ip) +{ + struct ftrace_func_entry *entry; + + entry = kmalloc(sizeof(*entry), GFP_KERNEL); + if (!entry) + return -ENOMEM; + + entry->ip = ip; + __add_hash_entry(hash, entry); return 0; } static void -remove_hash_entry(struct ftrace_hash *hash, +free_hash_entry(struct ftrace_hash *hash, struct ftrace_func_entry *entry) { hlist_del(&entry->hlist); @@ -973,6 +981,14 @@ remove_hash_entry(struct ftrace_hash *hash, hash->count--; } +static void +remove_hash_entry(struct ftrace_hash *hash, + struct ftrace_func_entry *entry) +{ + hlist_del(&entry->hlist); + hash->count--; +} + static void ftrace_hash_clear(struct ftrace_hash *hash) { struct hlist_head *hhd; @@ -981,14 +997,156 @@ static void ftrace_hash_clear(struct ftrace_hash *hash) int size = 1 << hash->size_bits; int i; + if (!hash->count) + return; + for (i = 0; i < size; i++) { hhd = &hash->buckets[i]; hlist_for_each_entry_safe(entry, tp, tn, hhd, hlist) - remove_hash_entry(hash, entry); + free_hash_entry(hash, entry); } FTRACE_WARN_ON(hash->count); } +static void free_ftrace_hash(struct ftrace_hash *hash) +{ + if (!hash || hash == EMPTY_HASH) + return; + ftrace_hash_clear(hash); + kfree(hash->buckets); + kfree(hash); +} + +static struct ftrace_hash *alloc_ftrace_hash(int size_bits) +{ + struct ftrace_hash *hash; + int size; + + hash = kzalloc(sizeof(*hash), GFP_KERNEL); + if (!hash) + return NULL; + + size = 1 << size_bits; + hash->buckets = kzalloc(sizeof(*hash->buckets) * size, GFP_KERNEL); + + if (!hash->buckets) { + kfree(hash); + return NULL; + } + + hash->size_bits = size_bits; + + return hash; +} + +static struct ftrace_hash * +alloc_and_copy_ftrace_hash(int size_bits, struct ftrace_hash *hash) +{ + struct ftrace_func_entry *entry; + struct ftrace_hash *new_hash; + struct hlist_node *tp; + int size; + int ret; + int i; + + new_hash = alloc_ftrace_hash(size_bits); + if (!new_hash) + return NULL; + + /* Empty hash? */ + if (!hash || !hash->count) + return new_hash; + + size = 1 << hash->size_bits; + for (i = 0; i < size; i++) { + hlist_for_each_entry(entry, tp, &hash->buckets[i], hlist) { + ret = add_hash_entry(new_hash, entry->ip); + if (ret < 0) + goto free_hash; + } + } + + FTRACE_WARN_ON(new_hash->count != hash->count); + + return new_hash; + + free_hash: + free_ftrace_hash(new_hash); + return NULL; +} + +static int +ftrace_hash_move(struct ftrace_hash **dst, struct ftrace_hash *src) +{ + struct ftrace_func_entry *entry; + struct hlist_node *tp, *tn; + struct hlist_head *hhd; + struct ftrace_hash *hash = *dst; + unsigned long key; + int size = src->count; + int bits = 0; + int i; + + /* + * If the new source is empty, just free dst and assign it + * the empty_hash. + */ + if (!src->count) { + free_ftrace_hash(*dst); + *dst = EMPTY_HASH; + return 0; + } + + ftrace_hash_clear(hash); + + /* + * Make the hash size about 1/2 the # found + */ + for (size /= 2; size; size >>= 1) + bits++; + + /* Don't allocate too much */ + if (bits > FTRACE_HASH_MAX_BITS) + bits = FTRACE_HASH_MAX_BITS; + + /* We can't modify the empty_hash */ + if (hash == EMPTY_HASH) { + /* Create a new hash */ + *dst = alloc_ftrace_hash(bits); + if (!*dst) { + *dst = EMPTY_HASH; + return -ENOMEM; + } + hash = *dst; + } else { + size = 1 << bits; + + /* Use the old hash, but create new buckets */ + hhd = kzalloc(sizeof(*hhd) * size, GFP_KERNEL); + if (!hhd) + return -ENOMEM; + + kfree(hash->buckets); + hash->buckets = hhd; + hash->size_bits = bits; + } + + size = 1 << src->size_bits; + for (i = 0; i < size; i++) { + hhd = &src->buckets[i]; + hlist_for_each_entry_safe(entry, tp, tn, hhd, hlist) { + if (bits > 0) + key = hash_long(entry->ip, bits); + else + key = 0; + remove_hash_entry(src, entry); + __add_hash_entry(hash, entry); + } + } + + return 0; +} + /* * This is a double for. Do not use 'break' to break out of the loop, * you must use a goto. @@ -1443,6 +1601,7 @@ struct ftrace_iterator { struct ftrace_func_probe *probe; struct trace_parser parser; struct ftrace_hash *hash; + struct ftrace_ops *ops; int hidx; int idx; unsigned flags; @@ -1742,22 +1901,37 @@ ftrace_regex_open(struct ftrace_ops *ops, int flag, else hash = ops->filter_hash; - iter->hash = hash; + iter->ops = ops; + iter->flags = flag; + + if (file->f_mode & FMODE_WRITE) { + mutex_lock(&ftrace_lock); + iter->hash = alloc_and_copy_ftrace_hash(FTRACE_HASH_DEFAULT_BITS, hash); + mutex_unlock(&ftrace_lock); + + if (!iter->hash) { + trace_parser_put(&iter->parser); + kfree(iter); + return -ENOMEM; + } + } mutex_lock(&ftrace_regex_lock); + if ((file->f_mode & FMODE_WRITE) && (file->f_flags & O_TRUNC)) - ftrace_filter_reset(hash); + ftrace_filter_reset(iter->hash); if (file->f_mode & FMODE_READ) { iter->pg = ftrace_pages_start; - iter->flags = flag; ret = seq_open(file, &show_ftrace_seq_ops); if (!ret) { struct seq_file *m = file->private_data; m->private = iter; } else { + /* Failed */ + free_ftrace_hash(iter->hash); trace_parser_put(&iter->parser); kfree(iter); } @@ -1835,7 +2009,7 @@ enter_record(struct ftrace_hash *hash, struct dyn_ftrace *rec, int not) if (!entry) return 0; - remove_hash_entry(hash, entry); + free_hash_entry(hash, entry); } else { /* Do nothing if it exists */ if (entry) @@ -2259,19 +2433,13 @@ int unregister_ftrace_command(struct ftrace_func_command *cmd) return ret; } -static int ftrace_process_regex(char *buff, int len, int enable) +static int ftrace_process_regex(struct ftrace_hash *hash, + char *buff, int len, int enable) { char *func, *command, *next = buff; - struct ftrace_ops *ops = &global_ops; struct ftrace_func_command *p; - struct ftrace_hash *hash; int ret; - if (enable) - hash = ops->filter_hash; - else - hash = ops->notrace_hash; - func = strsep(&next, ":"); if (!next) { @@ -2328,7 +2496,7 @@ ftrace_regex_write(struct file *file, const char __user *ubuf, if (read >= 0 && trace_parser_loaded(parser) && !trace_parser_cont(parser)) { - ret = ftrace_process_regex(parser->buffer, + ret = ftrace_process_regex(iter->hash, parser->buffer, parser->idx, enable); trace_parser_clear(parser); if (ret) @@ -2356,26 +2524,40 @@ ftrace_notrace_write(struct file *file, const char __user *ubuf, return ftrace_regex_write(file, ubuf, cnt, ppos, 0); } -static void +static int ftrace_set_regex(struct ftrace_ops *ops, unsigned char *buf, int len, int reset, int enable) { + struct ftrace_hash **orig_hash; struct ftrace_hash *hash; + int ret; if (unlikely(ftrace_disabled)) - return; + return -ENODEV; if (enable) - hash = ops->filter_hash; + orig_hash = &ops->filter_hash; else - hash = ops->notrace_hash; + orig_hash = &ops->notrace_hash; + + hash = alloc_and_copy_ftrace_hash(FTRACE_HASH_DEFAULT_BITS, *orig_hash); + if (!hash) + return -ENOMEM; mutex_lock(&ftrace_regex_lock); if (reset) ftrace_filter_reset(hash); if (buf) ftrace_match_records(hash, buf, len); + + mutex_lock(&ftrace_lock); + ret = ftrace_hash_move(orig_hash, hash); + mutex_unlock(&ftrace_lock); + mutex_unlock(&ftrace_regex_lock); + + free_ftrace_hash(hash); + return ret; } /** @@ -2484,7 +2666,9 @@ ftrace_regex_release(struct inode *inode, struct file *file) { struct seq_file *m = (struct seq_file *)file->private_data; struct ftrace_iterator *iter; + struct ftrace_hash **orig_hash; struct trace_parser *parser; + int ret; mutex_lock(&ftrace_regex_lock); if (file->f_mode & FMODE_READ) { @@ -2501,14 +2685,21 @@ ftrace_regex_release(struct inode *inode, struct file *file) } trace_parser_put(parser); - kfree(iter); if (file->f_mode & FMODE_WRITE) { + if (iter->flags & FTRACE_ITER_NOTRACE) + orig_hash = &iter->ops->notrace_hash; + else + orig_hash = &iter->ops->filter_hash; + mutex_lock(&ftrace_lock); - if (ftrace_start_up && ftrace_enabled) + ret = ftrace_hash_move(orig_hash, iter->hash); + if (!ret && ftrace_start_up && ftrace_enabled) ftrace_run_update_code(FTRACE_ENABLE_CALLS); mutex_unlock(&ftrace_lock); } + free_ftrace_hash(iter->hash); + kfree(iter); mutex_unlock(&ftrace_regex_lock); return 0; -- cgit v1.1 From ed926f9b35cda0988234c356e16a7cb30f4e5338 Mon Sep 17 00:00:00 2001 From: Steven Rostedt Date: Tue, 3 May 2011 13:25:24 -0400 Subject: ftrace: Use counters to enable functions to trace Every function has its own record that stores the instruction pointer and flags for the function to be traced. There are only two flags: enabled and free. The enabled flag states that tracing for the function has been enabled (actively traced), and the free flag states that the record no longer points to a function and can be used by new functions (loaded modules). These flags are now moved to the MSB of the flags (actually just the top 32bits). The rest of the bits (30 bits) are now used as a ref counter. Everytime a tracer register functions to trace, those functions will have its counter incremented. When tracing is enabled, to determine if a function should be traced, the counter is examined, and if it is non-zero it is set to trace. When a ftrace_ops is registered to trace functions, its hashes are examined. If the ftrace_ops filter_hash count is zero, then all functions are set to be traced, otherwise only the functions in the hash are to be traced. The exception to this is if a function is also in the ftrace_ops notrace_hash. Then that function's counter is not incremented for this ftrace_ops. Signed-off-by: Steven Rostedt --- kernel/trace/ftrace.c | 158 +++++++++++++++++++++++++++++++++++++++++++++----- 1 file changed, 142 insertions(+), 16 deletions(-) (limited to 'kernel') diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c index 46f0826..5dd332cc 100644 --- a/kernel/trace/ftrace.c +++ b/kernel/trace/ftrace.c @@ -890,6 +890,10 @@ static const struct ftrace_hash empty_hash = { }; #define EMPTY_HASH ((struct ftrace_hash *)&empty_hash) +enum { + FTRACE_OPS_FL_ENABLED = 1, +}; + struct ftrace_ops global_ops = { .func = ftrace_stub, .notrace_hash = EMPTY_HASH, @@ -1161,6 +1165,105 @@ ftrace_hash_move(struct ftrace_hash **dst, struct ftrace_hash *src) } \ } +static void __ftrace_hash_rec_update(struct ftrace_ops *ops, + int filter_hash, + bool inc) +{ + struct ftrace_hash *hash; + struct ftrace_hash *other_hash; + struct ftrace_page *pg; + struct dyn_ftrace *rec; + int count = 0; + int all = 0; + + /* Only update if the ops has been registered */ + if (!(ops->flags & FTRACE_OPS_FL_ENABLED)) + return; + + /* + * In the filter_hash case: + * If the count is zero, we update all records. + * Otherwise we just update the items in the hash. + * + * In the notrace_hash case: + * We enable the update in the hash. + * As disabling notrace means enabling the tracing, + * and enabling notrace means disabling, the inc variable + * gets inversed. + */ + if (filter_hash) { + hash = ops->filter_hash; + other_hash = ops->notrace_hash; + if (!hash->count) + all = 1; + } else { + inc = !inc; + hash = ops->notrace_hash; + other_hash = ops->filter_hash; + /* + * If the notrace hash has no items, + * then there's nothing to do. + */ + if (!hash->count) + return; + } + + do_for_each_ftrace_rec(pg, rec) { + int in_other_hash = 0; + int in_hash = 0; + int match = 0; + + if (all) { + /* + * Only the filter_hash affects all records. + * Update if the record is not in the notrace hash. + */ + if (!ftrace_lookup_ip(other_hash, rec->ip)) + match = 1; + } else { + in_hash = !!ftrace_lookup_ip(hash, rec->ip); + in_other_hash = !!ftrace_lookup_ip(other_hash, rec->ip); + + /* + * + */ + if (filter_hash && in_hash && !in_other_hash) + match = 1; + else if (!filter_hash && in_hash && + (in_other_hash || !other_hash->count)) + match = 1; + } + if (!match) + continue; + + if (inc) { + rec->flags++; + if (FTRACE_WARN_ON((rec->flags & ~FTRACE_FL_MASK) == FTRACE_REF_MAX)) + return; + } else { + if (FTRACE_WARN_ON((rec->flags & ~FTRACE_FL_MASK) == 0)) + return; + rec->flags--; + } + count++; + /* Shortcut, if we handled all records, we are done. */ + if (!all && count == hash->count) + return; + } while_for_each_ftrace_rec(); +} + +static void ftrace_hash_rec_disable(struct ftrace_ops *ops, + int filter_hash) +{ + __ftrace_hash_rec_update(ops, filter_hash, 0); +} + +static void ftrace_hash_rec_enable(struct ftrace_ops *ops, + int filter_hash) +{ + __ftrace_hash_rec_update(ops, filter_hash, 1); +} + static void ftrace_free_rec(struct dyn_ftrace *rec) { rec->freelist = ftrace_free_records; @@ -1276,26 +1379,24 @@ int ftrace_text_reserved(void *start, void *end) static int __ftrace_replace_code(struct dyn_ftrace *rec, int enable) { - struct ftrace_ops *ops = &global_ops; unsigned long ftrace_addr; unsigned long flag = 0UL; ftrace_addr = (unsigned long)FTRACE_ADDR; /* - * If this record is not to be traced or we want to disable it, - * then disable it. + * If we are enabling tracing: * - * If we want to enable it and filtering is off, then enable it. + * If the record has a ref count, then we need to enable it + * because someone is using it. * - * If we want to enable it and filtering is on, enable it only if - * it's filtered + * Otherwise we make sure its disabled. + * + * If we are disabling tracing, then disable all records that + * are enabled. */ - if (enable && !ftrace_lookup_ip(ops->notrace_hash, rec->ip)) { - if (!ops->filter_hash->count || - ftrace_lookup_ip(ops->filter_hash, rec->ip)) - flag = FTRACE_FL_ENABLED; - } + if (enable && (rec->flags & ~FTRACE_FL_MASK)) + flag = FTRACE_FL_ENABLED; /* If the state of this record hasn't changed, then do nothing */ if ((rec->flags & FTRACE_FL_ENABLED) == flag) @@ -1423,17 +1524,25 @@ static void ftrace_startup_enable(int command) static void ftrace_startup(int command) { + struct ftrace_ops *ops = &global_ops; + if (unlikely(ftrace_disabled)) return; ftrace_start_up++; command |= FTRACE_ENABLE_CALLS; + ops->flags |= FTRACE_OPS_FL_ENABLED; + if (ftrace_start_up == 1) + ftrace_hash_rec_enable(ops, 1); + ftrace_startup_enable(command); } static void ftrace_shutdown(int command) { + struct ftrace_ops *ops = &global_ops; + if (unlikely(ftrace_disabled)) return; @@ -1446,7 +1555,12 @@ static void ftrace_shutdown(int command) WARN_ON_ONCE(ftrace_start_up < 0); if (!ftrace_start_up) + ftrace_hash_rec_disable(ops, 1); + + if (!ftrace_start_up) { command |= FTRACE_DISABLE_CALLS; + ops->flags &= ~FTRACE_OPS_FL_ENABLED; + } if (saved_ftrace_func != ftrace_trace_function) { saved_ftrace_func = ftrace_trace_function; @@ -2668,6 +2782,7 @@ ftrace_regex_release(struct inode *inode, struct file *file) struct ftrace_iterator *iter; struct ftrace_hash **orig_hash; struct trace_parser *parser; + int filter_hash; int ret; mutex_lock(&ftrace_regex_lock); @@ -2687,15 +2802,26 @@ ftrace_regex_release(struct inode *inode, struct file *file) trace_parser_put(parser); if (file->f_mode & FMODE_WRITE) { - if (iter->flags & FTRACE_ITER_NOTRACE) - orig_hash = &iter->ops->notrace_hash; - else + filter_hash = !!(iter->flags & FTRACE_ITER_FILTER); + + if (filter_hash) orig_hash = &iter->ops->filter_hash; + else + orig_hash = &iter->ops->notrace_hash; mutex_lock(&ftrace_lock); + /* + * Remove the current set, update the hash and add + * them back. + */ + ftrace_hash_rec_disable(iter->ops, filter_hash); ret = ftrace_hash_move(orig_hash, iter->hash); - if (!ret && ftrace_start_up && ftrace_enabled) - ftrace_run_update_code(FTRACE_ENABLE_CALLS); + if (!ret) { + ftrace_hash_rec_enable(iter->ops, filter_hash); + if (iter->ops->flags & FTRACE_OPS_FL_ENABLED + && ftrace_enabled) + ftrace_run_update_code(FTRACE_ENABLE_CALLS); + } mutex_unlock(&ftrace_lock); } free_ftrace_hash(iter->hash); -- cgit v1.1 From 647bcd03d5b2fb44fd9c9ef1a4f50c2eee8f779a Mon Sep 17 00:00:00 2001 From: Steven Rostedt Date: Tue, 3 May 2011 14:39:21 -0400 Subject: ftrace: Add enabled_functions file Add the enabled_functions file that is used to show all the functions that have been enabled for tracing as well as their ref counts. This helps seeing if any function has been registered and what functions are being traced. Signed-off-by: Steven Rostedt --- kernel/trace/ftrace.c | 51 +++++++++++++++++++++++++++++++++++++++++++++++++-- 1 file changed, 49 insertions(+), 2 deletions(-) (limited to 'kernel') diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c index 5dd332cc..065f1e6 100644 --- a/kernel/trace/ftrace.c +++ b/kernel/trace/ftrace.c @@ -1703,6 +1703,7 @@ enum { FTRACE_ITER_NOTRACE = (1 << 1), FTRACE_ITER_PRINTALL = (1 << 2), FTRACE_ITER_HASH = (1 << 3), + FTRACE_ITER_ENABLED = (1 << 4), }; #define FTRACE_BUFF_MAX (KSYM_SYMBOL_LEN+4) /* room for wildcards */ @@ -1842,7 +1843,11 @@ t_next(struct seq_file *m, void *v, loff_t *pos) !(ftrace_lookup_ip(ops->filter_hash, rec->ip))) || ((iter->flags & FTRACE_ITER_NOTRACE) && - !ftrace_lookup_ip(ops->notrace_hash, rec->ip))) { + !ftrace_lookup_ip(ops->notrace_hash, rec->ip)) || + + ((iter->flags & FTRACE_ITER_ENABLED) && + !(rec->flags & ~FTRACE_FL_MASK))) { + rec = NULL; goto retry; } @@ -1944,7 +1949,11 @@ static int t_show(struct seq_file *m, void *v) if (!rec) return 0; - seq_printf(m, "%ps\n", (void *)rec->ip); + seq_printf(m, "%ps", (void *)rec->ip); + if (iter->flags & FTRACE_ITER_ENABLED) + seq_printf(m, " (%ld)", + rec->flags & ~FTRACE_FL_MASK); + seq_printf(m, "\n"); return 0; } @@ -1983,6 +1992,34 @@ ftrace_avail_open(struct inode *inode, struct file *file) return ret; } +static int +ftrace_enabled_open(struct inode *inode, struct file *file) +{ + struct ftrace_iterator *iter; + int ret; + + if (unlikely(ftrace_disabled)) + return -ENODEV; + + iter = kzalloc(sizeof(*iter), GFP_KERNEL); + if (!iter) + return -ENOMEM; + + iter->pg = ftrace_pages_start; + iter->flags = FTRACE_ITER_ENABLED; + + ret = seq_open(file, &show_ftrace_seq_ops); + if (!ret) { + struct seq_file *m = file->private_data; + + m->private = iter; + } else { + kfree(iter); + } + + return ret; +} + static void ftrace_filter_reset(struct ftrace_hash *hash) { mutex_lock(&ftrace_lock); @@ -2838,6 +2875,13 @@ static const struct file_operations ftrace_avail_fops = { .release = seq_release_private, }; +static const struct file_operations ftrace_enabled_fops = { + .open = ftrace_enabled_open, + .read = seq_read, + .llseek = seq_lseek, + .release = seq_release_private, +}; + static const struct file_operations ftrace_filter_fops = { .open = ftrace_filter_open, .read = seq_read, @@ -3069,6 +3113,9 @@ static __init int ftrace_init_dyn_debugfs(struct dentry *d_tracer) trace_create_file("available_filter_functions", 0444, d_tracer, NULL, &ftrace_avail_fops); + trace_create_file("enabled_functions", 0444, + d_tracer, NULL, &ftrace_enabled_fops); + trace_create_file("set_ftrace_filter", 0644, d_tracer, NULL, &ftrace_filter_fops); -- cgit v1.1 From bd69c30b1d08032d97ab0dabd7a1eb7fb73ca2b2 Mon Sep 17 00:00:00 2001 From: Steven Rostedt Date: Tue, 3 May 2011 21:55:54 -0400 Subject: ftrace: Add ops parameter to ftrace_startup/shutdown functions In order to allow different ops to enable different functions, the ftrace_startup() and ftrace_shutdown() functions need the ops parameter passed to them. Signed-off-by: Steven Rostedt --- kernel/trace/ftrace.c | 28 ++++++++++++++-------------- 1 file changed, 14 insertions(+), 14 deletions(-) (limited to 'kernel') diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c index 065f1e6..8fef1d9 100644 --- a/kernel/trace/ftrace.c +++ b/kernel/trace/ftrace.c @@ -1522,10 +1522,8 @@ static void ftrace_startup_enable(int command) ftrace_run_update_code(command); } -static void ftrace_startup(int command) +static void ftrace_startup(struct ftrace_ops *ops, int command) { - struct ftrace_ops *ops = &global_ops; - if (unlikely(ftrace_disabled)) return; @@ -1539,10 +1537,8 @@ static void ftrace_startup(int command) ftrace_startup_enable(command); } -static void ftrace_shutdown(int command) +static void ftrace_shutdown(struct ftrace_ops *ops, int command) { - struct ftrace_ops *ops = &global_ops; - if (unlikely(ftrace_disabled)) return; @@ -2362,7 +2358,7 @@ static void __enable_ftrace_function_probe(void) return; __register_ftrace_function(&trace_probe_ops); - ftrace_startup(0); + ftrace_startup(&global_ops, 0); ftrace_probe_registered = 1; } @@ -2381,7 +2377,7 @@ static void __disable_ftrace_function_probe(void) /* no more funcs left */ __unregister_ftrace_function(&trace_probe_ops); - ftrace_shutdown(0); + ftrace_shutdown(&global_ops, 0); ftrace_probe_registered = 0; } @@ -3267,6 +3263,10 @@ void __init ftrace_init(void) #else +struct ftrace_ops global_ops = { + .func = ftrace_stub, +}; + static int __init ftrace_nodyn_init(void) { ftrace_enabled = 1; @@ -3277,8 +3277,8 @@ device_initcall(ftrace_nodyn_init); static inline int ftrace_init_dyn_debugfs(struct dentry *d_tracer) { return 0; } static inline void ftrace_startup_enable(int command) { } /* Keep as macros so we do not need to define the commands */ -# define ftrace_startup(command) do { } while (0) -# define ftrace_shutdown(command) do { } while (0) +# define ftrace_startup(ops, command) do { } while (0) +# define ftrace_shutdown(ops, command) do { } while (0) # define ftrace_startup_sysctl() do { } while (0) # define ftrace_shutdown_sysctl() do { } while (0) #endif /* CONFIG_DYNAMIC_FTRACE */ @@ -3583,7 +3583,7 @@ int register_ftrace_function(struct ftrace_ops *ops) goto out_unlock; ret = __register_ftrace_function(ops); - ftrace_startup(0); + ftrace_startup(&global_ops, 0); out_unlock: mutex_unlock(&ftrace_lock); @@ -3602,7 +3602,7 @@ int unregister_ftrace_function(struct ftrace_ops *ops) mutex_lock(&ftrace_lock); ret = __unregister_ftrace_function(ops); - ftrace_shutdown(0); + ftrace_shutdown(&global_ops, 0); mutex_unlock(&ftrace_lock); return ret; @@ -3825,7 +3825,7 @@ int register_ftrace_graph(trace_func_graph_ret_t retfunc, ftrace_graph_return = retfunc; ftrace_graph_entry = entryfunc; - ftrace_startup(FTRACE_START_FUNC_RET); + ftrace_startup(&global_ops, FTRACE_START_FUNC_RET); out: mutex_unlock(&ftrace_lock); @@ -3842,7 +3842,7 @@ void unregister_ftrace_graph(void) ftrace_graph_active--; ftrace_graph_return = (trace_func_graph_ret_t)ftrace_stub; ftrace_graph_entry = ftrace_graph_entry_stub; - ftrace_shutdown(FTRACE_STOP_FUNC_RET); + ftrace_shutdown(&global_ops, FTRACE_STOP_FUNC_RET); unregister_pm_notifier(&ftrace_suspend_notifier); unregister_trace_sched_switch(ftrace_graph_probe_sched_switch, NULL); -- cgit v1.1 From 2b499381bc50ede01b3d8eab164ca2fad00655f0 Mon Sep 17 00:00:00 2001 From: Steven Rostedt Date: Tue, 3 May 2011 22:49:52 -0400 Subject: ftrace: Have global_ops store the functions that are to be traced This is a step towards each ops structure defining its own set of functions to trace. As the current code with pid's and such are specific to the global_ops, it is restructured to be used with the global ops. Signed-off-by: Steven Rostedt --- kernel/trace/ftrace.c | 69 +++++++++++++++++++++++++++++++++++++++------------ 1 file changed, 53 insertions(+), 16 deletions(-) (limited to 'kernel') diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c index 8fef1d9..dcce0bf 100644 --- a/kernel/trace/ftrace.c +++ b/kernel/trace/ftrace.c @@ -91,6 +91,7 @@ static struct ftrace_ops *ftrace_list __read_mostly = &ftrace_list_end; ftrace_func_t ftrace_trace_function __read_mostly = ftrace_stub; ftrace_func_t __ftrace_trace_function __read_mostly = ftrace_stub; ftrace_func_t ftrace_pid_function __read_mostly = ftrace_stub; +static struct ftrace_ops global_ops; /* * Traverse the ftrace_list, invoking all entries. The reason that we @@ -153,7 +154,7 @@ static void ftrace_test_stop_func(unsigned long ip, unsigned long parent_ip) } #endif -static void update_ftrace_function(void) +static void update_global_ops(void) { ftrace_func_t func; @@ -173,6 +174,18 @@ static void update_ftrace_function(void) set_ftrace_pid_function(func); func = ftrace_pid_func; } + + global_ops.func = func; +} + +static void update_ftrace_function(void) +{ + ftrace_func_t func; + + update_global_ops(); + + func = global_ops.func; + #ifdef CONFIG_HAVE_FUNCTION_TRACE_MCOUNT_TEST ftrace_trace_function = func; #else @@ -181,24 +194,19 @@ static void update_ftrace_function(void) #endif } -static int __register_ftrace_function(struct ftrace_ops *ops) +static void add_ftrace_ops(struct ftrace_ops **list, struct ftrace_ops *ops) { - ops->next = ftrace_list; + ops->next = *list; /* * We are entering ops into the ftrace_list but another * CPU might be walking that list. We need to make sure * the ops->next pointer is valid before another CPU sees * the ops pointer included into the ftrace_list. */ - rcu_assign_pointer(ftrace_list, ops); - - if (ftrace_enabled) - update_ftrace_function(); - - return 0; + rcu_assign_pointer(*list, ops); } -static int __unregister_ftrace_function(struct ftrace_ops *ops) +static int remove_ftrace_ops(struct ftrace_ops **list, struct ftrace_ops *ops) { struct ftrace_ops **p; @@ -206,13 +214,12 @@ static int __unregister_ftrace_function(struct ftrace_ops *ops) * If we are removing the last function, then simply point * to the ftrace_stub. */ - if (ftrace_list == ops && ops->next == &ftrace_list_end) { - ftrace_trace_function = ftrace_stub; - ftrace_list = &ftrace_list_end; + if (*list == ops && ops->next == &ftrace_list_end) { + *list = &ftrace_list_end; return 0; } - for (p = &ftrace_list; *p != &ftrace_list_end; p = &(*p)->next) + for (p = list; *p != &ftrace_list_end; p = &(*p)->next) if (*p == ops) break; @@ -220,7 +227,37 @@ static int __unregister_ftrace_function(struct ftrace_ops *ops) return -1; *p = (*p)->next; + return 0; +} + +static int __register_ftrace_function(struct ftrace_ops *ops) +{ + if (ftrace_disabled) + return -ENODEV; + + if (FTRACE_WARN_ON(ops == &global_ops)) + return -EINVAL; + + add_ftrace_ops(&ftrace_list, ops); + if (ftrace_enabled) + update_ftrace_function(); + + return 0; +} +static int __unregister_ftrace_function(struct ftrace_ops *ops) +{ + int ret; + + if (ftrace_disabled) + return -ENODEV; + + if (FTRACE_WARN_ON(ops == &global_ops)) + return -EINVAL; + + ret = remove_ftrace_ops(&ftrace_list, ops); + if (ret < 0) + return ret; if (ftrace_enabled) update_ftrace_function(); @@ -894,7 +931,7 @@ enum { FTRACE_OPS_FL_ENABLED = 1, }; -struct ftrace_ops global_ops = { +static struct ftrace_ops global_ops = { .func = ftrace_stub, .notrace_hash = EMPTY_HASH, .filter_hash = EMPTY_HASH, @@ -3263,7 +3300,7 @@ void __init ftrace_init(void) #else -struct ftrace_ops global_ops = { +static struct ftrace_ops global_ops = { .func = ftrace_stub, }; -- cgit v1.1 From 07fd5515f3b5c20704707f63e7f4485b534508a8 Mon Sep 17 00:00:00 2001 From: Steven Rostedt Date: Thu, 5 May 2011 18:03:47 -0400 Subject: ftrace: Free hash with call_rcu_sched() When a hash is modified and might be in use, we need to perform a schedule RCU operation on it, as the hashes will soon be used directly in the function tracer callback. Cc: Paul E. McKenney Signed-off-by: Steven Rostedt --- kernel/trace/ftrace.c | 55 ++++++++++++++++++++++++++------------------------- 1 file changed, 28 insertions(+), 27 deletions(-) (limited to 'kernel') diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c index dcce0bf..92b6fdf 100644 --- a/kernel/trace/ftrace.c +++ b/kernel/trace/ftrace.c @@ -913,6 +913,7 @@ struct ftrace_hash { unsigned long size_bits; struct hlist_head *buckets; unsigned long count; + struct rcu_head rcu; }; /* @@ -1058,6 +1059,21 @@ static void free_ftrace_hash(struct ftrace_hash *hash) kfree(hash); } +static void __free_ftrace_hash_rcu(struct rcu_head *rcu) +{ + struct ftrace_hash *hash; + + hash = container_of(rcu, struct ftrace_hash, rcu); + free_ftrace_hash(hash); +} + +static void free_ftrace_hash_rcu(struct ftrace_hash *hash) +{ + if (!hash || hash == EMPTY_HASH) + return; + call_rcu_sched(&hash->rcu, __free_ftrace_hash_rcu); +} + static struct ftrace_hash *alloc_ftrace_hash(int size_bits) { struct ftrace_hash *hash; @@ -1122,7 +1138,8 @@ ftrace_hash_move(struct ftrace_hash **dst, struct ftrace_hash *src) struct ftrace_func_entry *entry; struct hlist_node *tp, *tn; struct hlist_head *hhd; - struct ftrace_hash *hash = *dst; + struct ftrace_hash *old_hash; + struct ftrace_hash *new_hash; unsigned long key; int size = src->count; int bits = 0; @@ -1133,13 +1150,11 @@ ftrace_hash_move(struct ftrace_hash **dst, struct ftrace_hash *src) * the empty_hash. */ if (!src->count) { - free_ftrace_hash(*dst); - *dst = EMPTY_HASH; + free_ftrace_hash_rcu(*dst); + rcu_assign_pointer(*dst, EMPTY_HASH); return 0; } - ftrace_hash_clear(hash); - /* * Make the hash size about 1/2 the # found */ @@ -1150,27 +1165,9 @@ ftrace_hash_move(struct ftrace_hash **dst, struct ftrace_hash *src) if (bits > FTRACE_HASH_MAX_BITS) bits = FTRACE_HASH_MAX_BITS; - /* We can't modify the empty_hash */ - if (hash == EMPTY_HASH) { - /* Create a new hash */ - *dst = alloc_ftrace_hash(bits); - if (!*dst) { - *dst = EMPTY_HASH; - return -ENOMEM; - } - hash = *dst; - } else { - size = 1 << bits; - - /* Use the old hash, but create new buckets */ - hhd = kzalloc(sizeof(*hhd) * size, GFP_KERNEL); - if (!hhd) - return -ENOMEM; - - kfree(hash->buckets); - hash->buckets = hhd; - hash->size_bits = bits; - } + new_hash = alloc_ftrace_hash(bits); + if (!new_hash) + return -ENOMEM; size = 1 << src->size_bits; for (i = 0; i < size; i++) { @@ -1181,10 +1178,14 @@ ftrace_hash_move(struct ftrace_hash **dst, struct ftrace_hash *src) else key = 0; remove_hash_entry(src, entry); - __add_hash_entry(hash, entry); + __add_hash_entry(new_hash, entry); } } + old_hash = *dst; + rcu_assign_pointer(*dst, new_hash); + free_ftrace_hash_rcu(old_hash); + return 0; } -- cgit v1.1 From b848914ce39589d89ee0078a6d1ef452b464729e Mon Sep 17 00:00:00 2001 From: Steven Rostedt Date: Wed, 4 May 2011 09:27:52 -0400 Subject: ftrace: Implement separate user function filtering ftrace_ops that are registered to trace functions can now be agnostic to each other in respect to what functions they trace. Each ops has their own hash of the functions they want to trace and a hash to what they do not want to trace. A empty hash for the functions they want to trace denotes all functions should be traced that are not in the notrace hash. Cc: Paul E. McKenney Signed-off-by: Steven Rostedt --- kernel/trace/ftrace.c | 193 ++++++++++++++++++++++++++++++-------- kernel/trace/trace_functions.c | 2 + kernel/trace/trace_irqsoff.c | 1 + kernel/trace/trace_sched_wakeup.c | 1 + kernel/trace/trace_stack.c | 1 + 5 files changed, 160 insertions(+), 38 deletions(-) (limited to 'kernel') diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c index 92b6fdf..6c7e1df 100644 --- a/kernel/trace/ftrace.c +++ b/kernel/trace/ftrace.c @@ -87,24 +87,29 @@ static struct ftrace_ops ftrace_list_end __read_mostly = .func = ftrace_stub, }; -static struct ftrace_ops *ftrace_list __read_mostly = &ftrace_list_end; +static struct ftrace_ops *ftrace_global_list __read_mostly = &ftrace_list_end; +static struct ftrace_ops *ftrace_ops_list __read_mostly = &ftrace_list_end; ftrace_func_t ftrace_trace_function __read_mostly = ftrace_stub; ftrace_func_t __ftrace_trace_function __read_mostly = ftrace_stub; ftrace_func_t ftrace_pid_function __read_mostly = ftrace_stub; static struct ftrace_ops global_ops; +static void +ftrace_ops_list_func(unsigned long ip, unsigned long parent_ip); + /* - * Traverse the ftrace_list, invoking all entries. The reason that we + * Traverse the ftrace_global_list, invoking all entries. The reason that we * can use rcu_dereference_raw() is that elements removed from this list * are simply leaked, so there is no need to interact with a grace-period * mechanism. The rcu_dereference_raw() calls are needed to handle - * concurrent insertions into the ftrace_list. + * concurrent insertions into the ftrace_global_list. * * Silly Alpha and silly pointer-speculation compiler optimizations! */ -static void ftrace_list_func(unsigned long ip, unsigned long parent_ip) +static void ftrace_global_list_func(unsigned long ip, + unsigned long parent_ip) { - struct ftrace_ops *op = rcu_dereference_raw(ftrace_list); /*see above*/ + struct ftrace_ops *op = rcu_dereference_raw(ftrace_global_list); /*see above*/ while (op != &ftrace_list_end) { op->func(ip, parent_ip); @@ -163,11 +168,11 @@ static void update_global_ops(void) * function directly. Otherwise, we need to iterate over the * registered callers. */ - if (ftrace_list == &ftrace_list_end || - ftrace_list->next == &ftrace_list_end) - func = ftrace_list->func; + if (ftrace_global_list == &ftrace_list_end || + ftrace_global_list->next == &ftrace_list_end) + func = ftrace_global_list->func; else - func = ftrace_list_func; + func = ftrace_global_list_func; /* If we filter on pids, update to use the pid function */ if (!list_empty(&ftrace_pids)) { @@ -184,7 +189,11 @@ static void update_ftrace_function(void) update_global_ops(); - func = global_ops.func; + if (ftrace_ops_list == &ftrace_list_end || + ftrace_ops_list->next == &ftrace_list_end) + func = ftrace_ops_list->func; + else + func = ftrace_ops_list_func; #ifdef CONFIG_HAVE_FUNCTION_TRACE_MCOUNT_TEST ftrace_trace_function = func; @@ -198,10 +207,10 @@ static void add_ftrace_ops(struct ftrace_ops **list, struct ftrace_ops *ops) { ops->next = *list; /* - * We are entering ops into the ftrace_list but another + * We are entering ops into the list but another * CPU might be walking that list. We need to make sure * the ops->next pointer is valid before another CPU sees - * the ops pointer included into the ftrace_list. + * the ops pointer included into the list. */ rcu_assign_pointer(*list, ops); } @@ -238,7 +247,18 @@ static int __register_ftrace_function(struct ftrace_ops *ops) if (FTRACE_WARN_ON(ops == &global_ops)) return -EINVAL; - add_ftrace_ops(&ftrace_list, ops); + if (WARN_ON(ops->flags & FTRACE_OPS_FL_ENABLED)) + return -EBUSY; + + if (ops->flags & FTRACE_OPS_FL_GLOBAL) { + int first = ftrace_global_list == &ftrace_list_end; + add_ftrace_ops(&ftrace_global_list, ops); + ops->flags |= FTRACE_OPS_FL_ENABLED; + if (first) + add_ftrace_ops(&ftrace_ops_list, &global_ops); + } else + add_ftrace_ops(&ftrace_ops_list, ops); + if (ftrace_enabled) update_ftrace_function(); @@ -252,12 +272,24 @@ static int __unregister_ftrace_function(struct ftrace_ops *ops) if (ftrace_disabled) return -ENODEV; + if (WARN_ON(!(ops->flags & FTRACE_OPS_FL_ENABLED))) + return -EBUSY; + if (FTRACE_WARN_ON(ops == &global_ops)) return -EINVAL; - ret = remove_ftrace_ops(&ftrace_list, ops); + if (ops->flags & FTRACE_OPS_FL_GLOBAL) { + ret = remove_ftrace_ops(&ftrace_global_list, ops); + if (!ret && ftrace_global_list == &ftrace_list_end) + ret = remove_ftrace_ops(&ftrace_ops_list, &global_ops); + if (!ret) + ops->flags &= ~FTRACE_OPS_FL_ENABLED; + } else + ret = remove_ftrace_ops(&ftrace_ops_list, ops); + if (ret < 0) return ret; + if (ftrace_enabled) update_ftrace_function(); @@ -928,10 +960,6 @@ static const struct ftrace_hash empty_hash = { }; #define EMPTY_HASH ((struct ftrace_hash *)&empty_hash) -enum { - FTRACE_OPS_FL_ENABLED = 1, -}; - static struct ftrace_ops global_ops = { .func = ftrace_stub, .notrace_hash = EMPTY_HASH, @@ -1190,6 +1218,40 @@ ftrace_hash_move(struct ftrace_hash **dst, struct ftrace_hash *src) } /* + * Test the hashes for this ops to see if we want to call + * the ops->func or not. + * + * It's a match if the ip is in the ops->filter_hash or + * the filter_hash does not exist or is empty, + * AND + * the ip is not in the ops->notrace_hash. + */ +static int +ftrace_ops_test(struct ftrace_ops *ops, unsigned long ip) +{ + struct ftrace_hash *filter_hash; + struct ftrace_hash *notrace_hash; + int ret; + + /* The hashes are freed with call_rcu_sched() */ + preempt_disable_notrace(); + + filter_hash = rcu_dereference_raw(ops->filter_hash); + notrace_hash = rcu_dereference_raw(ops->notrace_hash); + + if ((!filter_hash || !filter_hash->count || + ftrace_lookup_ip(filter_hash, ip)) && + (!notrace_hash || !notrace_hash->count || + !ftrace_lookup_ip(notrace_hash, ip))) + ret = 1; + else + ret = 0; + preempt_enable_notrace(); + + return ret; +} + +/* * This is a double for. Do not use 'break' to break out of the loop, * you must use a goto. */ @@ -1232,7 +1294,7 @@ static void __ftrace_hash_rec_update(struct ftrace_ops *ops, if (filter_hash) { hash = ops->filter_hash; other_hash = ops->notrace_hash; - if (!hash->count) + if (!hash || !hash->count) all = 1; } else { inc = !inc; @@ -1242,7 +1304,7 @@ static void __ftrace_hash_rec_update(struct ftrace_ops *ops, * If the notrace hash has no items, * then there's nothing to do. */ - if (!hash->count) + if (hash && !hash->count) return; } @@ -1256,11 +1318,11 @@ static void __ftrace_hash_rec_update(struct ftrace_ops *ops, * Only the filter_hash affects all records. * Update if the record is not in the notrace hash. */ - if (!ftrace_lookup_ip(other_hash, rec->ip)) + if (!other_hash || !ftrace_lookup_ip(other_hash, rec->ip)) match = 1; } else { - in_hash = !!ftrace_lookup_ip(hash, rec->ip); - in_other_hash = !!ftrace_lookup_ip(other_hash, rec->ip); + in_hash = hash && !!ftrace_lookup_ip(hash, rec->ip); + in_other_hash = other_hash && !!ftrace_lookup_ip(other_hash, rec->ip); /* * @@ -1546,6 +1608,7 @@ static void ftrace_run_update_code(int command) static ftrace_func_t saved_ftrace_func; static int ftrace_start_up; +static int global_start_up; static void ftrace_startup_enable(int command) { @@ -1562,14 +1625,25 @@ static void ftrace_startup_enable(int command) static void ftrace_startup(struct ftrace_ops *ops, int command) { + bool hash_enable = true; + if (unlikely(ftrace_disabled)) return; ftrace_start_up++; command |= FTRACE_ENABLE_CALLS; + /* ops marked global share the filter hashes */ + if (ops->flags & FTRACE_OPS_FL_GLOBAL) { + ops = &global_ops; + /* Don't update hash if global is already set */ + if (global_start_up) + hash_enable = false; + global_start_up++; + } + ops->flags |= FTRACE_OPS_FL_ENABLED; - if (ftrace_start_up == 1) + if (hash_enable) ftrace_hash_rec_enable(ops, 1); ftrace_startup_enable(command); @@ -1577,6 +1651,8 @@ static void ftrace_startup(struct ftrace_ops *ops, int command) static void ftrace_shutdown(struct ftrace_ops *ops, int command) { + bool hash_disable = true; + if (unlikely(ftrace_disabled)) return; @@ -1588,13 +1664,25 @@ static void ftrace_shutdown(struct ftrace_ops *ops, int command) */ WARN_ON_ONCE(ftrace_start_up < 0); - if (!ftrace_start_up) + if (ops->flags & FTRACE_OPS_FL_GLOBAL) { + ops = &global_ops; + global_start_up--; + WARN_ON_ONCE(global_start_up < 0); + /* Don't update hash if global still has users */ + if (global_start_up) { + WARN_ON_ONCE(!ftrace_start_up); + hash_disable = false; + } + } + + if (hash_disable) ftrace_hash_rec_disable(ops, 1); - if (!ftrace_start_up) { - command |= FTRACE_DISABLE_CALLS; + if (ops != &global_ops || !global_start_up) ops->flags &= ~FTRACE_OPS_FL_ENABLED; - } + + if (!ftrace_start_up) + command |= FTRACE_DISABLE_CALLS; if (saved_ftrace_func != ftrace_trace_function) { saved_ftrace_func = ftrace_trace_function; @@ -2381,6 +2469,7 @@ static int ftrace_probe_registered; static void __enable_ftrace_function_probe(void) { + int ret; int i; if (ftrace_probe_registered) @@ -2395,13 +2484,16 @@ static void __enable_ftrace_function_probe(void) if (i == FTRACE_FUNC_HASHSIZE) return; - __register_ftrace_function(&trace_probe_ops); - ftrace_startup(&global_ops, 0); + ret = __register_ftrace_function(&trace_probe_ops); + if (!ret) + ftrace_startup(&trace_probe_ops, 0); + ftrace_probe_registered = 1; } static void __disable_ftrace_function_probe(void) { + int ret; int i; if (!ftrace_probe_registered) @@ -2414,8 +2506,10 @@ static void __disable_ftrace_function_probe(void) } /* no more funcs left */ - __unregister_ftrace_function(&trace_probe_ops); - ftrace_shutdown(&global_ops, 0); + ret = __unregister_ftrace_function(&trace_probe_ops); + if (!ret) + ftrace_shutdown(&trace_probe_ops, 0); + ftrace_probe_registered = 0; } @@ -3319,8 +3413,28 @@ static inline void ftrace_startup_enable(int command) { } # define ftrace_shutdown(ops, command) do { } while (0) # define ftrace_startup_sysctl() do { } while (0) # define ftrace_shutdown_sysctl() do { } while (0) + +static inline int +ftrace_ops_test(struct ftrace_ops *ops, unsigned long ip) +{ + return 1; +} + #endif /* CONFIG_DYNAMIC_FTRACE */ +static void +ftrace_ops_list_func(unsigned long ip, unsigned long parent_ip) +{ + /* see comment above ftrace_global_list_func */ + struct ftrace_ops *op = rcu_dereference_raw(ftrace_ops_list); + + while (op != &ftrace_list_end) { + if (ftrace_ops_test(op, ip)) + op->func(ip, parent_ip); + op = rcu_dereference_raw(op->next); + }; +} + static void clear_ftrace_swapper(void) { struct task_struct *p; @@ -3621,7 +3735,9 @@ int register_ftrace_function(struct ftrace_ops *ops) goto out_unlock; ret = __register_ftrace_function(ops); - ftrace_startup(&global_ops, 0); + if (!ret) + ftrace_startup(ops, 0); + out_unlock: mutex_unlock(&ftrace_lock); @@ -3640,7 +3756,8 @@ int unregister_ftrace_function(struct ftrace_ops *ops) mutex_lock(&ftrace_lock); ret = __unregister_ftrace_function(ops); - ftrace_shutdown(&global_ops, 0); + if (!ret) + ftrace_shutdown(ops, 0); mutex_unlock(&ftrace_lock); return ret; @@ -3670,11 +3787,11 @@ ftrace_enable_sysctl(struct ctl_table *table, int write, ftrace_startup_sysctl(); /* we are starting ftrace again */ - if (ftrace_list != &ftrace_list_end) { - if (ftrace_list->next == &ftrace_list_end) - ftrace_trace_function = ftrace_list->func; + if (ftrace_ops_list != &ftrace_list_end) { + if (ftrace_ops_list->next == &ftrace_list_end) + ftrace_trace_function = ftrace_ops_list->func; else - ftrace_trace_function = ftrace_list_func; + ftrace_trace_function = ftrace_ops_list_func; } } else { diff --git a/kernel/trace/trace_functions.c b/kernel/trace/trace_functions.c index 16aee4d..8d0e1cc 100644 --- a/kernel/trace/trace_functions.c +++ b/kernel/trace/trace_functions.c @@ -149,11 +149,13 @@ function_stack_trace_call(unsigned long ip, unsigned long parent_ip) static struct ftrace_ops trace_ops __read_mostly = { .func = function_trace_call, + .flags = FTRACE_OPS_FL_GLOBAL, }; static struct ftrace_ops trace_stack_ops __read_mostly = { .func = function_stack_trace_call, + .flags = FTRACE_OPS_FL_GLOBAL, }; /* Our two options */ diff --git a/kernel/trace/trace_irqsoff.c b/kernel/trace/trace_irqsoff.c index a4969b4..c77424b 100644 --- a/kernel/trace/trace_irqsoff.c +++ b/kernel/trace/trace_irqsoff.c @@ -153,6 +153,7 @@ irqsoff_tracer_call(unsigned long ip, unsigned long parent_ip) static struct ftrace_ops trace_ops __read_mostly = { .func = irqsoff_tracer_call, + .flags = FTRACE_OPS_FL_GLOBAL, }; #endif /* CONFIG_FUNCTION_TRACER */ diff --git a/kernel/trace/trace_sched_wakeup.c b/kernel/trace/trace_sched_wakeup.c index 7319559..f029dd4 100644 --- a/kernel/trace/trace_sched_wakeup.c +++ b/kernel/trace/trace_sched_wakeup.c @@ -129,6 +129,7 @@ wakeup_tracer_call(unsigned long ip, unsigned long parent_ip) static struct ftrace_ops trace_ops __read_mostly = { .func = wakeup_tracer_call, + .flags = FTRACE_OPS_FL_GLOBAL, }; #endif /* CONFIG_FUNCTION_TRACER */ diff --git a/kernel/trace/trace_stack.c b/kernel/trace/trace_stack.c index 4c5dead..b0b53b8 100644 --- a/kernel/trace/trace_stack.c +++ b/kernel/trace/trace_stack.c @@ -133,6 +133,7 @@ stack_trace_call(unsigned long ip, unsigned long parent_ip) static struct ftrace_ops trace_ops __read_mostly = { .func = stack_trace_call, + .flags = FTRACE_OPS_FL_GLOBAL, }; static ssize_t -- cgit v1.1 From cdbe61bfe70440939e457fb4a8d0995eaaed17de Mon Sep 17 00:00:00 2001 From: Steven Rostedt Date: Thu, 5 May 2011 21:14:55 -0400 Subject: ftrace: Allow dynamically allocated function tracers Now that functions may be selected individually, it only makes sense that we should allow dynamically allocated trace structures to be traced. This will allow perf to allocate a ftrace_ops structure at runtime and use it to pick and choose which functions that structure will trace. Note, a dynamically allocated ftrace_ops will always be called indirectly instead of being called directly from the mcount in entry.S. This is because there's no safe way to prevent mcount from being preempted before calling the function, unless we modify every entry.S to do so (not likely). Thus, dynamically allocated functions will now be called by the ftrace_ops_list_func() that loops through the ops that are allocated if there are more than one op allocated at a time. This loop is protected with a preempt_disable. To determine if an ftrace_ops structure is allocated or not, a new util function was added to the kernel/extable.c called core_kernel_data(), which returns 1 if the address is between _sdata and _edata. Cc: Paul E. McKenney Signed-off-by: Steven Rostedt --- kernel/extable.c | 8 ++++++++ kernel/trace/ftrace.c | 37 ++++++++++++++++++++++++++++++------- 2 files changed, 38 insertions(+), 7 deletions(-) (limited to 'kernel') diff --git a/kernel/extable.c b/kernel/extable.c index 7f8f263..c2d625f 100644 --- a/kernel/extable.c +++ b/kernel/extable.c @@ -72,6 +72,14 @@ int core_kernel_text(unsigned long addr) return 0; } +int core_kernel_data(unsigned long addr) +{ + if (addr >= (unsigned long)_sdata && + addr < (unsigned long)_edata) + return 1; + return 0; +} + int __kernel_text_address(unsigned long addr) { if (core_kernel_text(addr)) diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c index 6c7e1df..5b3ee04 100644 --- a/kernel/trace/ftrace.c +++ b/kernel/trace/ftrace.c @@ -189,8 +189,14 @@ static void update_ftrace_function(void) update_global_ops(); + /* + * If we are at the end of the list and this ops is + * not dynamic, then have the mcount trampoline call + * the function directly + */ if (ftrace_ops_list == &ftrace_list_end || - ftrace_ops_list->next == &ftrace_list_end) + (ftrace_ops_list->next == &ftrace_list_end && + !(ftrace_ops_list->flags & FTRACE_OPS_FL_DYNAMIC))) func = ftrace_ops_list->func; else func = ftrace_ops_list_func; @@ -250,6 +256,9 @@ static int __register_ftrace_function(struct ftrace_ops *ops) if (WARN_ON(ops->flags & FTRACE_OPS_FL_ENABLED)) return -EBUSY; + if (!core_kernel_data((unsigned long)ops)) + ops->flags |= FTRACE_OPS_FL_DYNAMIC; + if (ops->flags & FTRACE_OPS_FL_GLOBAL) { int first = ftrace_global_list == &ftrace_list_end; add_ftrace_ops(&ftrace_global_list, ops); @@ -293,6 +302,13 @@ static int __unregister_ftrace_function(struct ftrace_ops *ops) if (ftrace_enabled) update_ftrace_function(); + /* + * Dynamic ops may be freed, we must make sure that all + * callers are done before leaving this function. + */ + if (ops->flags & FTRACE_OPS_FL_DYNAMIC) + synchronize_sched(); + return 0; } @@ -1225,6 +1241,9 @@ ftrace_hash_move(struct ftrace_hash **dst, struct ftrace_hash *src) * the filter_hash does not exist or is empty, * AND * the ip is not in the ops->notrace_hash. + * + * This needs to be called with preemption disabled as + * the hashes are freed with call_rcu_sched(). */ static int ftrace_ops_test(struct ftrace_ops *ops, unsigned long ip) @@ -1233,9 +1252,6 @@ ftrace_ops_test(struct ftrace_ops *ops, unsigned long ip) struct ftrace_hash *notrace_hash; int ret; - /* The hashes are freed with call_rcu_sched() */ - preempt_disable_notrace(); - filter_hash = rcu_dereference_raw(ops->filter_hash); notrace_hash = rcu_dereference_raw(ops->notrace_hash); @@ -1246,7 +1262,6 @@ ftrace_ops_test(struct ftrace_ops *ops, unsigned long ip) ret = 1; else ret = 0; - preempt_enable_notrace(); return ret; } @@ -3425,14 +3440,20 @@ ftrace_ops_test(struct ftrace_ops *ops, unsigned long ip) static void ftrace_ops_list_func(unsigned long ip, unsigned long parent_ip) { - /* see comment above ftrace_global_list_func */ - struct ftrace_ops *op = rcu_dereference_raw(ftrace_ops_list); + struct ftrace_ops *op; + /* + * Some of the ops may be dynamically allocated, + * they must be freed after a synchronize_sched(). + */ + preempt_disable_notrace(); + op = rcu_dereference_raw(ftrace_ops_list); while (op != &ftrace_list_end) { if (ftrace_ops_test(op, ip)) op->func(ip, parent_ip); op = rcu_dereference_raw(op->next); }; + preempt_enable_notrace(); } static void clear_ftrace_swapper(void) @@ -3743,6 +3764,7 @@ int register_ftrace_function(struct ftrace_ops *ops) mutex_unlock(&ftrace_lock); return ret; } +EXPORT_SYMBOL_GPL(register_ftrace_function); /** * unregister_ftrace_function - unregister a function for profiling. @@ -3762,6 +3784,7 @@ int unregister_ftrace_function(struct ftrace_ops *ops) return ret; } +EXPORT_SYMBOL_GPL(unregister_ftrace_function); int ftrace_enable_sysctl(struct ctl_table *table, int write, -- cgit v1.1 From 936e074b286ae779f134312178dbab139ee7ea52 Mon Sep 17 00:00:00 2001 From: Steven Rostedt Date: Thu, 5 May 2011 22:54:01 -0400 Subject: ftrace: Modify ftrace_set_filter/notrace to take ops Since users of the function tracer can now pick and choose which functions they want to trace agnostically from other users of the function tracer, we need to pass the ops struct to the ftrace_set_filter() functions. The functions ftrace_set_global_filter() and ftrace_set_global_notrace() is added to keep the old filter functions which are used to modify the generic function tracers. Signed-off-by: Steven Rostedt --- kernel/trace/ftrace.c | 46 +++++++++++++++++++++++++++++++++++++++++-- kernel/trace/trace_selftest.c | 4 ++-- 2 files changed, 46 insertions(+), 4 deletions(-) (limited to 'kernel') diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c index 5b3ee04..d017c2c 100644 --- a/kernel/trace/ftrace.c +++ b/kernel/trace/ftrace.c @@ -2826,6 +2826,10 @@ ftrace_set_regex(struct ftrace_ops *ops, unsigned char *buf, int len, struct ftrace_hash *hash; int ret; + /* All global ops uses the global ops filters */ + if (ops->flags & FTRACE_OPS_FL_GLOBAL) + ops = &global_ops; + if (unlikely(ftrace_disabled)) return -ENODEV; @@ -2856,6 +2860,41 @@ ftrace_set_regex(struct ftrace_ops *ops, unsigned char *buf, int len, /** * ftrace_set_filter - set a function to filter on in ftrace + * @ops - the ops to set the filter with + * @buf - the string that holds the function filter text. + * @len - the length of the string. + * @reset - non zero to reset all filters before applying this filter. + * + * Filters denote which functions should be enabled when tracing is enabled. + * If @buf is NULL and reset is set, all functions will be enabled for tracing. + */ +void ftrace_set_filter(struct ftrace_ops *ops, unsigned char *buf, + int len, int reset) +{ + ftrace_set_regex(ops, buf, len, reset, 1); +} +EXPORT_SYMBOL_GPL(ftrace_set_filter); + +/** + * ftrace_set_notrace - set a function to not trace in ftrace + * @ops - the ops to set the notrace filter with + * @buf - the string that holds the function notrace text. + * @len - the length of the string. + * @reset - non zero to reset all filters before applying this filter. + * + * Notrace Filters denote which functions should not be enabled when tracing + * is enabled. If @buf is NULL and reset is set, all functions will be enabled + * for tracing. + */ +void ftrace_set_notrace(struct ftrace_ops *ops, unsigned char *buf, + int len, int reset) +{ + ftrace_set_regex(ops, buf, len, reset, 0); +} +EXPORT_SYMBOL_GPL(ftrace_set_notrace); +/** + * ftrace_set_filter - set a function to filter on in ftrace + * @ops - the ops to set the filter with * @buf - the string that holds the function filter text. * @len - the length of the string. * @reset - non zero to reset all filters before applying this filter. @@ -2863,13 +2902,15 @@ ftrace_set_regex(struct ftrace_ops *ops, unsigned char *buf, int len, * Filters denote which functions should be enabled when tracing is enabled. * If @buf is NULL and reset is set, all functions will be enabled for tracing. */ -void ftrace_set_filter(unsigned char *buf, int len, int reset) +void ftrace_set_global_filter(unsigned char *buf, int len, int reset) { ftrace_set_regex(&global_ops, buf, len, reset, 1); } +EXPORT_SYMBOL_GPL(ftrace_set_global_filter); /** * ftrace_set_notrace - set a function to not trace in ftrace + * @ops - the ops to set the notrace filter with * @buf - the string that holds the function notrace text. * @len - the length of the string. * @reset - non zero to reset all filters before applying this filter. @@ -2878,10 +2919,11 @@ void ftrace_set_filter(unsigned char *buf, int len, int reset) * is enabled. If @buf is NULL and reset is set, all functions will be enabled * for tracing. */ -void ftrace_set_notrace(unsigned char *buf, int len, int reset) +void ftrace_set_global_notrace(unsigned char *buf, int len, int reset) { ftrace_set_regex(&global_ops, buf, len, reset, 0); } +EXPORT_SYMBOL_GPL(ftrace_set_global_notrace); /* * command line interface to allow users to set filters on boot up. diff --git a/kernel/trace/trace_selftest.c b/kernel/trace/trace_selftest.c index 659732e..0fa2db3 100644 --- a/kernel/trace/trace_selftest.c +++ b/kernel/trace/trace_selftest.c @@ -131,7 +131,7 @@ int trace_selftest_startup_dynamic_tracing(struct tracer *trace, func_name = "*" __stringify(DYN_FTRACE_TEST_NAME); /* filter only on our function */ - ftrace_set_filter(func_name, strlen(func_name), 1); + ftrace_set_global_filter(func_name, strlen(func_name), 1); /* enable tracing */ ret = tracer_init(trace, tr); @@ -181,7 +181,7 @@ int trace_selftest_startup_dynamic_tracing(struct tracer *trace, tracer_enabled = save_tracer_enabled; /* Enable tracing on all functions again */ - ftrace_set_filter(NULL, 0, 1); + ftrace_set_global_filter(NULL, 0, 1); return ret; } -- cgit v1.1 From 95950c2ecb31314ef827428e43ff771cf3b037e5 Mon Sep 17 00:00:00 2001 From: Steven Rostedt Date: Fri, 6 May 2011 00:08:51 -0400 Subject: ftrace: Add self-tests for multiple function trace users Add some basic sanity tests for multiple users of the function tracer at startup. Signed-off-by: Steven Rostedt --- kernel/trace/trace.h | 2 + kernel/trace/trace_selftest.c | 210 +++++++++++++++++++++++++++++++++- kernel/trace/trace_selftest_dynamic.c | 6 + 3 files changed, 217 insertions(+), 1 deletion(-) (limited to 'kernel') diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h index 5e9dfc6..6b69c4b 100644 --- a/kernel/trace/trace.h +++ b/kernel/trace/trace.h @@ -419,6 +419,8 @@ extern void trace_find_cmdline(int pid, char comm[]); extern unsigned long ftrace_update_tot_cnt; #define DYN_FTRACE_TEST_NAME trace_selftest_dynamic_test_func extern int DYN_FTRACE_TEST_NAME(void); +#define DYN_FTRACE_TEST_NAME2 trace_selftest_dynamic_test_func2 +extern int DYN_FTRACE_TEST_NAME2(void); #endif extern int ring_buffer_expanded; diff --git a/kernel/trace/trace_selftest.c b/kernel/trace/trace_selftest.c index 0fa2db3..288541f 100644 --- a/kernel/trace/trace_selftest.c +++ b/kernel/trace/trace_selftest.c @@ -101,6 +101,206 @@ static inline void warn_failed_init_tracer(struct tracer *trace, int init_ret) #ifdef CONFIG_DYNAMIC_FTRACE +static int trace_selftest_test_probe1_cnt; +static void trace_selftest_test_probe1_func(unsigned long ip, + unsigned long pip) +{ + trace_selftest_test_probe1_cnt++; +} + +static int trace_selftest_test_probe2_cnt; +static void trace_selftest_test_probe2_func(unsigned long ip, + unsigned long pip) +{ + trace_selftest_test_probe2_cnt++; +} + +static int trace_selftest_test_probe3_cnt; +static void trace_selftest_test_probe3_func(unsigned long ip, + unsigned long pip) +{ + trace_selftest_test_probe3_cnt++; +} + +static int trace_selftest_test_global_cnt; +static void trace_selftest_test_global_func(unsigned long ip, + unsigned long pip) +{ + trace_selftest_test_global_cnt++; +} + +static int trace_selftest_test_dyn_cnt; +static void trace_selftest_test_dyn_func(unsigned long ip, + unsigned long pip) +{ + trace_selftest_test_dyn_cnt++; +} + +static struct ftrace_ops test_probe1 = { + .func = trace_selftest_test_probe1_func, +}; + +static struct ftrace_ops test_probe2 = { + .func = trace_selftest_test_probe2_func, +}; + +static struct ftrace_ops test_probe3 = { + .func = trace_selftest_test_probe3_func, +}; + +static struct ftrace_ops test_global = { + .func = trace_selftest_test_global_func, + .flags = FTRACE_OPS_FL_GLOBAL, +}; + +static void print_counts(void) +{ + printk("(%d %d %d %d %d) ", + trace_selftest_test_probe1_cnt, + trace_selftest_test_probe2_cnt, + trace_selftest_test_probe3_cnt, + trace_selftest_test_global_cnt, + trace_selftest_test_dyn_cnt); +} + +static void reset_counts(void) +{ + trace_selftest_test_probe1_cnt = 0; + trace_selftest_test_probe2_cnt = 0; + trace_selftest_test_probe3_cnt = 0; + trace_selftest_test_global_cnt = 0; + trace_selftest_test_dyn_cnt = 0; +} + +static int trace_selftest_ops(int cnt) +{ + int save_ftrace_enabled = ftrace_enabled; + struct ftrace_ops *dyn_ops; + char *func1_name; + char *func2_name; + int len1; + int len2; + int ret = -1; + + printk(KERN_CONT "PASSED\n"); + pr_info("Testing dynamic ftrace ops #%d: ", cnt); + + ftrace_enabled = 1; + reset_counts(); + + /* Handle PPC64 '.' name */ + func1_name = "*" __stringify(DYN_FTRACE_TEST_NAME); + func2_name = "*" __stringify(DYN_FTRACE_TEST_NAME2); + len1 = strlen(func1_name); + len2 = strlen(func2_name); + + /* + * Probe 1 will trace function 1. + * Probe 2 will trace function 2. + * Probe 3 will trace functions 1 and 2. + */ + ftrace_set_filter(&test_probe1, func1_name, len1, 1); + ftrace_set_filter(&test_probe2, func2_name, len2, 1); + ftrace_set_filter(&test_probe3, func1_name, len1, 1); + ftrace_set_filter(&test_probe3, func2_name, len2, 0); + + register_ftrace_function(&test_probe1); + register_ftrace_function(&test_probe2); + register_ftrace_function(&test_probe3); + register_ftrace_function(&test_global); + + DYN_FTRACE_TEST_NAME(); + + print_counts(); + + if (trace_selftest_test_probe1_cnt != 1) + goto out; + if (trace_selftest_test_probe2_cnt != 0) + goto out; + if (trace_selftest_test_probe3_cnt != 1) + goto out; + if (trace_selftest_test_global_cnt == 0) + goto out; + + DYN_FTRACE_TEST_NAME2(); + + print_counts(); + + if (trace_selftest_test_probe1_cnt != 1) + goto out; + if (trace_selftest_test_probe2_cnt != 1) + goto out; + if (trace_selftest_test_probe3_cnt != 2) + goto out; + + /* Add a dynamic probe */ + dyn_ops = kzalloc(sizeof(*dyn_ops), GFP_KERNEL); + if (!dyn_ops) { + printk("MEMORY ERROR "); + goto out; + } + + dyn_ops->func = trace_selftest_test_dyn_func; + + register_ftrace_function(dyn_ops); + + trace_selftest_test_global_cnt = 0; + + DYN_FTRACE_TEST_NAME(); + + print_counts(); + + if (trace_selftest_test_probe1_cnt != 2) + goto out_free; + if (trace_selftest_test_probe2_cnt != 1) + goto out_free; + if (trace_selftest_test_probe3_cnt != 3) + goto out_free; + if (trace_selftest_test_global_cnt == 0) + goto out; + if (trace_selftest_test_dyn_cnt == 0) + goto out_free; + + DYN_FTRACE_TEST_NAME2(); + + print_counts(); + + if (trace_selftest_test_probe1_cnt != 2) + goto out_free; + if (trace_selftest_test_probe2_cnt != 2) + goto out_free; + if (trace_selftest_test_probe3_cnt != 4) + goto out_free; + + ret = 0; + out_free: + unregister_ftrace_function(dyn_ops); + kfree(dyn_ops); + + out: + /* Purposely unregister in the same order */ + unregister_ftrace_function(&test_probe1); + unregister_ftrace_function(&test_probe2); + unregister_ftrace_function(&test_probe3); + unregister_ftrace_function(&test_global); + + /* Make sure everything is off */ + reset_counts(); + DYN_FTRACE_TEST_NAME(); + DYN_FTRACE_TEST_NAME(); + + if (trace_selftest_test_probe1_cnt || + trace_selftest_test_probe2_cnt || + trace_selftest_test_probe3_cnt || + trace_selftest_test_global_cnt || + trace_selftest_test_dyn_cnt) + ret = -1; + + ftrace_enabled = save_ftrace_enabled; + + return ret; +} + /* Test dynamic code modification and ftrace filters */ int trace_selftest_startup_dynamic_tracing(struct tracer *trace, struct trace_array *tr, @@ -166,16 +366,20 @@ int trace_selftest_startup_dynamic_tracing(struct tracer *trace, /* check the trace buffer */ ret = trace_test_buffer(tr, &count); - trace->reset(tr); tracing_start(); /* we should only have one item */ if (!ret && count != 1) { + trace->reset(tr); printk(KERN_CONT ".. filter failed count=%ld ..", count); ret = -1; goto out; } + /* Test the ops with global tracing running */ + ret = trace_selftest_ops(1); + trace->reset(tr); + out: ftrace_enabled = save_ftrace_enabled; tracer_enabled = save_tracer_enabled; @@ -183,6 +387,10 @@ int trace_selftest_startup_dynamic_tracing(struct tracer *trace, /* Enable tracing on all functions again */ ftrace_set_global_filter(NULL, 0, 1); + /* Test the ops with global tracing off */ + if (!ret) + ret = trace_selftest_ops(2); + return ret; } #else diff --git a/kernel/trace/trace_selftest_dynamic.c b/kernel/trace/trace_selftest_dynamic.c index 54dd77c..b4c475a 100644 --- a/kernel/trace/trace_selftest_dynamic.c +++ b/kernel/trace/trace_selftest_dynamic.c @@ -5,3 +5,9 @@ int DYN_FTRACE_TEST_NAME(void) /* used to call mcount */ return 0; } + +int DYN_FTRACE_TEST_NAME2(void) +{ + /* used to call mcount */ + return 0; +} -- cgit v1.1 From b4bc842802db3314f9a657094da0450a903ea619 Mon Sep 17 00:00:00 2001 From: Dmitry Torokhov Date: Mon, 7 Feb 2011 16:02:25 -0800 Subject: module: deal with alignment issues in built-in module versions On m68k natural alignment is 2-byte boundary but we are trying to align structures in __modver section on sizeof(void *) boundary. This causes trouble when we try to access elements in this section in array-like fashion when create "version" attributes for built-in modules. Moreover, as DaveM said, we can't reliably put structures into independent objects, put them into a special section, and then expect array access over them (via the section boundaries) after linking the objects together to just "work" due to variable alignment choices in different situations. The only solution that seems to work reliably is to make an array of plain pointers to the objects in question and put those pointers in the special section. Reported-by: Geert Uytterhoeven Signed-off-by: Dmitry Torokhov Signed-off-by: Rusty Russell --- kernel/params.c | 9 ++++++--- 1 file changed, 6 insertions(+), 3 deletions(-) (limited to 'kernel') diff --git a/kernel/params.c b/kernel/params.c index 7ab388a..28c5d5c 100644 --- a/kernel/params.c +++ b/kernel/params.c @@ -821,15 +821,18 @@ ssize_t __modver_version_show(struct module_attribute *mattr, return sprintf(buf, "%s\n", vattr->version); } -extern struct module_version_attribute __start___modver[], __stop___modver[]; +extern const struct module_version_attribute *__start___modver[]; +extern const struct module_version_attribute *__stop___modver[]; static void __init version_sysfs_builtin(void) { - const struct module_version_attribute *vattr; + const struct module_version_attribute **p; struct module_kobject *mk; int err; - for (vattr = __start___modver; vattr < __stop___modver; vattr++) { + for (p = __start___modver; p < __stop___modver; p++) { + const struct module_version_attribute *vattr = *p; + mk = locate_module_kobject(vattr->module_name); if (mk) { err = sysfs_create_file(&mk->kobj, &vattr->mattr.attr); -- cgit v1.1 From 5d05c70849f760ac8f4ed3ebfeefb92689858834 Mon Sep 17 00:00:00 2001 From: Daniel J Blueman Date: Tue, 8 Mar 2011 22:01:47 +0800 Subject: minor ANSI prototype sparse fix Fix function prototype to be ANSI-C compliant, consistent with other function prototypes, addressing a sparse warning. Signed-off-by: Daniel J Blueman Signed-off-by: Rusty Russell --- kernel/module.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) (limited to 'kernel') diff --git a/kernel/module.c b/kernel/module.c index d5938a5..523c40b71 100644 --- a/kernel/module.c +++ b/kernel/module.c @@ -1627,7 +1627,7 @@ void unset_section_ro_nx(struct module *mod, void *module_region) } /* Iterate through all modules and set each module's text as RW */ -void set_all_modules_text_rw() +void set_all_modules_text_rw(void) { struct module *mod; @@ -1648,7 +1648,7 @@ void set_all_modules_text_rw() } /* Iterate through all modules and set each module's text as RO */ -void set_all_modules_text_ro() +void set_all_modules_text_ro(void) { struct module *mod; -- cgit v1.1 From 4d10380e720a3ce19dbe88d0133f66ded07b6a8f Mon Sep 17 00:00:00 2001 From: Jan Glauber Date: Thu, 19 May 2011 16:55:25 -0600 Subject: module: zero mod->init_ro_size after init is freed. Reset mod->init_ro_size to zero after the init part of a module is unloaded. Otherwise we need to check if module->init is NULL in the unprotect functions in the next patch. Signed-off-by: Jan Glauber Signed-off-by: Rusty Russell --- kernel/module.c | 1 + 1 file changed, 1 insertion(+) (limited to 'kernel') diff --git a/kernel/module.c b/kernel/module.c index 523c40b71..92112c9 100644 --- a/kernel/module.c +++ b/kernel/module.c @@ -2935,6 +2935,7 @@ SYSCALL_DEFINE3(init_module, void __user *, umod, module_free(mod, mod->module_init); mod->module_init = NULL; mod->init_size = 0; + mod->init_ro_size = 0; mod->init_text_size = 0; mutex_unlock(&module_mutex); -- cgit v1.1 From 448694a1d50432be63aafccb42d6f54d8cf3d02c Mon Sep 17 00:00:00 2001 From: Jan Glauber Date: Thu, 19 May 2011 16:55:26 -0600 Subject: module: undo module RONX protection correctly. While debugging I stumbled over two problems in the code that protects module pages. First issue is that disabling the protection before freeing init or unload of a module is not symmetric with the enablement. For instance, if pages are set to RO the page range from module_core to module_core + core_ro_size is protected. If a module is unloaded the page range from module_core to module_core + core_size is set back to RW. So pages that were not set to RO are also changed to RW. This is not critical but IMHO it should be symmetric. Second issue is that while set_memory_rw & set_memory_ro are used for RO/RW changes only set_memory_nx is involved for NX/X. One would await that the inverse function is called when the NX protection should be removed, which is not the case here, unless I'm missing something. Signed-off-by: Jan Glauber Signed-off-by: Rusty Russell --- kernel/module.c | 25 +++++++++++++------------ 1 file changed, 13 insertions(+), 12 deletions(-) (limited to 'kernel') diff --git a/kernel/module.c b/kernel/module.c index 92112c9..b99dceb 100644 --- a/kernel/module.c +++ b/kernel/module.c @@ -1607,22 +1607,23 @@ static void set_section_ro_nx(void *base, } } -/* Setting memory back to RW+NX before releasing it */ +/* Setting memory back to W+X before releasing it */ void unset_section_ro_nx(struct module *mod, void *module_region) { - unsigned long total_pages; - if (mod->module_core == module_region) { - /* Set core as NX+RW */ - total_pages = MOD_NUMBER_OF_PAGES(mod->module_core, mod->core_size); - set_memory_nx((unsigned long)mod->module_core, total_pages); - set_memory_rw((unsigned long)mod->module_core, total_pages); - + set_page_attributes(mod->module_core + mod->core_text_size, + mod->module_core + mod->core_size, + set_memory_x); + set_page_attributes(mod->module_core, + mod->module_core + mod->core_ro_size, + set_memory_rw); } else if (mod->module_init == module_region) { - /* Set init as NX+RW */ - total_pages = MOD_NUMBER_OF_PAGES(mod->module_init, mod->init_size); - set_memory_nx((unsigned long)mod->module_init, total_pages); - set_memory_rw((unsigned long)mod->module_init, total_pages); + set_page_attributes(mod->module_init + mod->init_text_size, + mod->module_init + mod->init_size, + set_memory_x); + set_page_attributes(mod->module_init, + mod->module_init + mod->init_ro_size, + set_memory_rw); } } -- cgit v1.1 From 01526ed0830643bd53a8434c3068e4c077e1b09d Mon Sep 17 00:00:00 2001 From: Jan Glauber Date: Thu, 19 May 2011 16:55:26 -0600 Subject: module: split unset_section_ro_nx function. Split the unprotect function into a function per section to make the code more readable and add the missing static declaration. Signed-off-by: Jan Glauber Signed-off-by: Rusty Russell --- kernel/module.c | 45 +++++++++++++++++++++++---------------------- 1 file changed, 23 insertions(+), 22 deletions(-) (limited to 'kernel') diff --git a/kernel/module.c b/kernel/module.c index b99dceb..0e6f97f 100644 --- a/kernel/module.c +++ b/kernel/module.c @@ -1607,24 +1607,24 @@ static void set_section_ro_nx(void *base, } } -/* Setting memory back to W+X before releasing it */ -void unset_section_ro_nx(struct module *mod, void *module_region) -{ - if (mod->module_core == module_region) { - set_page_attributes(mod->module_core + mod->core_text_size, - mod->module_core + mod->core_size, - set_memory_x); - set_page_attributes(mod->module_core, - mod->module_core + mod->core_ro_size, - set_memory_rw); - } else if (mod->module_init == module_region) { - set_page_attributes(mod->module_init + mod->init_text_size, - mod->module_init + mod->init_size, - set_memory_x); - set_page_attributes(mod->module_init, - mod->module_init + mod->init_ro_size, - set_memory_rw); - } +static void unset_module_core_ro_nx(struct module *mod) +{ + set_page_attributes(mod->module_core + mod->core_text_size, + mod->module_core + mod->core_size, + set_memory_x); + set_page_attributes(mod->module_core, + mod->module_core + mod->core_ro_size, + set_memory_rw); +} + +static void unset_module_init_ro_nx(struct module *mod) +{ + set_page_attributes(mod->module_init + mod->init_text_size, + mod->module_init + mod->init_size, + set_memory_x); + set_page_attributes(mod->module_init, + mod->module_init + mod->init_ro_size, + set_memory_rw); } /* Iterate through all modules and set each module's text as RW */ @@ -1670,7 +1670,8 @@ void set_all_modules_text_ro(void) } #else static inline void set_section_ro_nx(void *base, unsigned long text_size, unsigned long ro_size, unsigned long total_size) { } -static inline void unset_section_ro_nx(struct module *mod, void *module_region) { } +static void unset_module_core_ro_nx(struct module *mod) { } +static void unset_module_init_ro_nx(struct module *mod) { } #endif /* Free a module, remove from lists, etc. */ @@ -1697,7 +1698,7 @@ static void free_module(struct module *mod) destroy_params(mod->kp, mod->num_kp); /* This may be NULL, but that's OK */ - unset_section_ro_nx(mod, mod->module_init); + unset_module_init_ro_nx(mod); module_free(mod, mod->module_init); kfree(mod->args); percpu_modfree(mod); @@ -1706,7 +1707,7 @@ static void free_module(struct module *mod) lockdep_free_key_range(mod->module_core, mod->core_size); /* Finally, free the core (containing the module structure) */ - unset_section_ro_nx(mod, mod->module_core); + unset_module_core_ro_nx(mod); module_free(mod, mod->module_core); #ifdef CONFIG_MPU @@ -2932,7 +2933,7 @@ SYSCALL_DEFINE3(init_module, void __user *, umod, mod->symtab = mod->core_symtab; mod->strtab = mod->core_strtab; #endif - unset_section_ro_nx(mod, mod->module_init); + unset_module_init_ro_nx(mod); module_free(mod, mod->module_init); mod->module_init = NULL; mod->init_size = 0; -- cgit v1.1 From de4d8d53465483168d6a627d409ee2d09d8e3308 Mon Sep 17 00:00:00 2001 From: Rusty Russell Date: Tue, 19 Apr 2011 21:49:58 +0200 Subject: module: each_symbol_section instead of each_symbol Instead of having a callback function for each symbol in the kernel, have a callback for each array of symbols. This eases the logic when we move to sorted symbols and binary search. Signed-off-by: Rusty Russell Signed-off-by: Alessio Igor Bogani --- kernel/module.c | 42 +++++++++++++++++++++++++++--------------- 1 file changed, 27 insertions(+), 15 deletions(-) (limited to 'kernel') diff --git a/kernel/module.c b/kernel/module.c index 0e6f97f..e8aa462 100644 --- a/kernel/module.c +++ b/kernel/module.c @@ -240,23 +240,24 @@ static bool each_symbol_in_section(const struct symsearch *arr, struct module *owner, bool (*fn)(const struct symsearch *syms, struct module *owner, - unsigned int symnum, void *data), + void *data), void *data) { - unsigned int i, j; + unsigned int j; for (j = 0; j < arrsize; j++) { - for (i = 0; i < arr[j].stop - arr[j].start; i++) - if (fn(&arr[j], owner, i, data)) - return true; + if (fn(&arr[j], owner, data)) + return true; } return false; } /* Returns true as soon as fn returns true, otherwise false. */ -bool each_symbol(bool (*fn)(const struct symsearch *arr, struct module *owner, - unsigned int symnum, void *data), void *data) +bool each_symbol_section(bool (*fn)(const struct symsearch *arr, + struct module *owner, + void *data), + void *data) { struct module *mod; static const struct symsearch arr[] = { @@ -309,7 +310,7 @@ bool each_symbol(bool (*fn)(const struct symsearch *arr, struct module *owner, } return false; } -EXPORT_SYMBOL_GPL(each_symbol); +EXPORT_SYMBOL_GPL(each_symbol_section); struct find_symbol_arg { /* Input */ @@ -323,15 +324,12 @@ struct find_symbol_arg { const struct kernel_symbol *sym; }; -static bool find_symbol_in_section(const struct symsearch *syms, - struct module *owner, - unsigned int symnum, void *data) +static bool check_symbol(const struct symsearch *syms, + struct module *owner, + unsigned int symnum, void *data) { struct find_symbol_arg *fsa = data; - if (strcmp(syms->start[symnum].name, fsa->name) != 0) - return false; - if (!fsa->gplok) { if (syms->licence == GPL_ONLY) return false; @@ -365,6 +363,20 @@ static bool find_symbol_in_section(const struct symsearch *syms, return true; } +static bool find_symbol_in_section(const struct symsearch *syms, + struct module *owner, + void *data) +{ + struct find_symbol_arg *fsa = data; + unsigned int i; + + for (i = 0; i < syms->stop - syms->start; i++) { + if (strcmp(syms->start[i].name, fsa->name) == 0) + return check_symbol(syms, owner, i, data); + } + return false; +} + /* Find a symbol and return it, along with, (optional) crc and * (optional) module which owns it. Needs preempt disabled or module_mutex. */ const struct kernel_symbol *find_symbol(const char *name, @@ -379,7 +391,7 @@ const struct kernel_symbol *find_symbol(const char *name, fsa.gplok = gplok; fsa.warn = warn; - if (each_symbol(find_symbol_in_section, &fsa)) { + if (each_symbol_section(find_symbol_in_section, &fsa)) { if (owner) *owner = fsa.owner; if (crc) -- cgit v1.1 From 403ed27846aa126ecf0b842b5b179c506b9d989c Mon Sep 17 00:00:00 2001 From: Alessio Igor Bogani Date: Wed, 20 Apr 2011 11:10:52 +0200 Subject: module: Use the binary search for symbols resolution Takes advantage of the order and locates symbols using binary search. This work was supported by a hardware donation from the CE Linux Forum. Signed-off-by: Alessio Igor Bogani Signed-off-by: Rusty Russell Tested-by: Dirk Behme --- kernel/module.c | 21 ++++++++++++++++----- 1 file changed, 16 insertions(+), 5 deletions(-) (limited to 'kernel') diff --git a/kernel/module.c b/kernel/module.c index e8aa462..d1db8eb 100644 --- a/kernel/module.c +++ b/kernel/module.c @@ -57,6 +57,7 @@ #include #include #include +#include #define CREATE_TRACE_POINTS #include @@ -363,17 +364,27 @@ static bool check_symbol(const struct symsearch *syms, return true; } +static int cmp_name(const void *va, const void *vb) +{ + const char *a; + const struct kernel_symbol *b; + a = va; b = vb; + return strcmp(a, b->name); +} + static bool find_symbol_in_section(const struct symsearch *syms, struct module *owner, void *data) { struct find_symbol_arg *fsa = data; - unsigned int i; + struct kernel_symbol *sym; + + sym = bsearch(fsa->name, syms->start, syms->stop - syms->start, + sizeof(struct kernel_symbol), cmp_name); + + if (sym != NULL && check_symbol(syms, owner, sym - syms->start, data)) + return true; - for (i = 0; i < syms->stop - syms->start; i++) { - if (strcmp(syms->start[i].name, fsa->name) == 0) - return check_symbol(syms, owner, i, data); - } return false; } -- cgit v1.1 From 9d63487f86115b1d3ef69670043bcf2b83c4d227 Mon Sep 17 00:00:00 2001 From: Alessio Igor Bogani Date: Wed, 18 May 2011 22:35:59 +0200 Subject: module: Use binary search in lookup_symbol() The function is_exported() with its helper function lookup_symbol() are used to verify if a provided symbol is effectively exported by the kernel or by the modules. Now that both have their symbols sorted we can replace a linear search with a binary search which provide a considerably speed-up. This work was supported by a hardware donation from the CE Linux Forum. Signed-off-by: Alessio Igor Bogani Acked-by: Greg Kroah-Hartman Signed-off-by: Rusty Russell --- kernel/module.c | 7 ++----- 1 file changed, 2 insertions(+), 5 deletions(-) (limited to 'kernel') diff --git a/kernel/module.c b/kernel/module.c index d1db8eb..2287972 100644 --- a/kernel/module.c +++ b/kernel/module.c @@ -2055,11 +2055,8 @@ static const struct kernel_symbol *lookup_symbol(const char *name, const struct kernel_symbol *start, const struct kernel_symbol *stop) { - const struct kernel_symbol *ks = start; - for (; ks < stop; ks++) - if (strcmp(ks->name, name) == 0) - return ks; - return NULL; + return bsearch(name, start, stop - start, + sizeof(struct kernel_symbol), cmp_name); } static int is_exported(const char *name, unsigned long value, -- cgit v1.1 From f721a465cddbe7f03e6cd2272008da558cf93818 Mon Sep 17 00:00:00 2001 From: Jonathan Cameron Date: Tue, 19 Apr 2011 12:43:47 +0100 Subject: params.c: Use new strtobool function to process boolean inputs Signed-off-by: Jonathan Cameron Signed-off-by: Rusty Russell --- kernel/params.c | 14 ++++---------- 1 file changed, 4 insertions(+), 10 deletions(-) (limited to 'kernel') diff --git a/kernel/params.c b/kernel/params.c index 28c5d5c..ed72e13 100644 --- a/kernel/params.c +++ b/kernel/params.c @@ -297,21 +297,15 @@ EXPORT_SYMBOL(param_ops_charp); int param_set_bool(const char *val, const struct kernel_param *kp) { bool v; + int ret; /* No equals means "set"... */ if (!val) val = "1"; /* One of =[yYnN01] */ - switch (val[0]) { - case 'y': case 'Y': case '1': - v = true; - break; - case 'n': case 'N': case '0': - v = false; - break; - default: - return -EINVAL; - } + ret = strtobool(val, &v); + if (ret) + return ret; if (kp->flags & KPARAM_ISBOOL) *(bool *)kp->arg = v; -- cgit v1.1 From 724ed53e8ac2c5278af8955673049714c1073464 Mon Sep 17 00:00:00 2001 From: Thomas Gleixner Date: Wed, 18 May 2011 21:33:40 +0000 Subject: clocksource: Get rid of the hardcoded 5 seconds sleep time limit Slow clocksources can have a way longer sleep time than 5 seconds and even fast ones can easily cope with 600 seconds and still maintain proper accuracy. Signed-off-by: Thomas Gleixner Cc: John Stultz Reviewed-by: Ingo Molnar Link: http://lkml.kernel.org/r/%3C20110518210136.109811585%40linutronix.de%3E --- kernel/time/clocksource.c | 38 +++++++++++++++++++------------------- 1 file changed, 19 insertions(+), 19 deletions(-) (limited to 'kernel') diff --git a/kernel/time/clocksource.c b/kernel/time/clocksource.c index 6519cf62..6dbbbb1 100644 --- a/kernel/time/clocksource.c +++ b/kernel/time/clocksource.c @@ -626,19 +626,6 @@ static void clocksource_enqueue(struct clocksource *cs) list_add(&cs->list, entry); } - -/* - * Maximum time we expect to go between ticks. This includes idle - * tickless time. It provides the trade off between selecting a - * mult/shift pair that is very precise but can only handle a short - * period of time, vs. a mult/shift pair that can handle long periods - * of time but isn't as precise. - * - * This is a subsystem constant, and actual hardware limitations - * may override it (ie: clocksources that wrap every 3 seconds). - */ -#define MAX_UPDATE_LENGTH 5 /* Seconds */ - /** * __clocksource_updatefreq_scale - Used update clocksource with new freq * @t: clocksource to be registered @@ -652,15 +639,28 @@ static void clocksource_enqueue(struct clocksource *cs) */ void __clocksource_updatefreq_scale(struct clocksource *cs, u32 scale, u32 freq) { + unsigned long sec; + /* - * Ideally we want to use some of the limits used in - * clocksource_max_deferment, to provide a more informed - * MAX_UPDATE_LENGTH. But for now this just gets the - * register interface working properly. + * Calc the maximum number of seconds which we can run before + * wrapping around. For clocksources which have a mask > 32bit + * we need to limit the max sleep time to have a good + * conversion precision. 10 minutes is still a reasonable + * amount. That results in a shift value of 24 for a + * clocksource with mask >= 40bit and f >= 4GHz. That maps to + * ~ 0.06ppm granularity for NTP. We apply the same 12.5% + * margin as we do in clocksource_max_deferment() */ + sec = (cs->mask - (cs->mask >> 5)); + do_div(sec, freq); + do_div(sec, scale); + if (!sec) + sec = 1; + else if (sec > 600 && cs->mask > UINT_MAX) + sec = 600; + clocks_calc_mult_shift(&cs->mult, &cs->shift, freq, - NSEC_PER_SEC/scale, - MAX_UPDATE_LENGTH*scale); + NSEC_PER_SEC / scale, sec * scale); cs->max_idle_ns = clocksource_max_deferment(cs); } EXPORT_SYMBOL_GPL(__clocksource_updatefreq_scale); -- cgit v1.1 From 57f0fcbe1dea8a36c9d1673086326059991c5f81 Mon Sep 17 00:00:00 2001 From: Thomas Gleixner Date: Wed, 18 May 2011 21:33:41 +0000 Subject: clockevents: Provide combined configure and register function All clockevent devices have the same open coded initialization functions. Provide an interface which does all necessary initialization in the core code. Signed-off-by: Thomas Gleixner Cc: John Stultz Reviewed-by: Ingo Molnar Link: http://lkml.kernel.org/r/%3C20110518210136.331975870%40linutronix.de%3E --- kernel/time/clockevents.c | 44 ++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 44 insertions(+) (limited to 'kernel') diff --git a/kernel/time/clockevents.c b/kernel/time/clockevents.c index 0d74b9b..c69e88c 100644 --- a/kernel/time/clockevents.c +++ b/kernel/time/clockevents.c @@ -194,6 +194,50 @@ void clockevents_register_device(struct clock_event_device *dev) } EXPORT_SYMBOL_GPL(clockevents_register_device); +static void clockevents_config(struct clock_event_device *dev, + u32 freq) +{ + unsigned long sec; + + if (!(dev->features & CLOCK_EVT_FEAT_ONESHOT)) + return; + + /* + * Calculate the maximum number of seconds we can sleep. Limit + * to 10 minutes for hardware which can program more than + * 32bit ticks so we still get reasonable conversion values. + */ + sec = dev->max_delta_ticks; + do_div(sec, freq); + if (!sec) + sec = 1; + else if (sec > 600 && dev->max_delta_ticks > UINT_MAX) + sec = 600; + + clockevents_calc_mult_shift(dev, freq, sec); + dev->min_delta_ns = clockevent_delta2ns(dev->min_delta_ticks, dev); + dev->max_delta_ns = clockevent_delta2ns(dev->max_delta_ticks, dev); +} + +/** + * clockevents_config_and_register - Configure and register a clock event device + * @dev: device to register + * @freq: The clock frequency + * @min_delta: The minimum clock ticks to program in oneshot mode + * @max_delta: The maximum clock ticks to program in oneshot mode + * + * min/max_delta can be 0 for devices which do not support oneshot mode. + */ +void clockevents_config_and_register(struct clock_event_device *dev, + u32 freq, unsigned long min_delta, + unsigned long max_delta) +{ + dev->min_delta_ticks = min_delta; + dev->max_delta_ticks = max_delta; + clockevents_config(dev, freq); + clockevents_register_device(dev); +} + /* * Noop handler when we shut down an event device */ -- cgit v1.1 From 80b816b736cfa5b9582279127099b20a479ab7d9 Mon Sep 17 00:00:00 2001 From: Thomas Gleixner Date: Wed, 18 May 2011 21:33:42 +0000 Subject: clockevents: Provide interface to reconfigure an active clock event device Some ARM SoCs have clock event devices which have their frequency modified due to frequency scaling. Provide an interface which allows to reconfigure an active device. After reconfiguration reprogram the current pending event. Signed-off-by: Thomas Gleixner Cc: LAK Cc: John Stultz Acked-by: Linus Walleij Reviewed-by: Ingo Molnar Link: http://lkml.kernel.org/r/%3C20110518210136.437459958%40linutronix.de%3E --- kernel/time/clockevents.c | 20 ++++++++++++++++++++ 1 file changed, 20 insertions(+) (limited to 'kernel') diff --git a/kernel/time/clockevents.c b/kernel/time/clockevents.c index c69e88c..22a9da9 100644 --- a/kernel/time/clockevents.c +++ b/kernel/time/clockevents.c @@ -238,6 +238,26 @@ void clockevents_config_and_register(struct clock_event_device *dev, clockevents_register_device(dev); } +/** + * clockevents_update_freq - Update frequency and reprogram a clock event device. + * @dev: device to modify + * @freq: new device frequency + * + * Reconfigure and reprogram a clock event device in oneshot + * mode. Must be called on the cpu for which the device delivers per + * cpu timer events with interrupts disabled! Returns 0 on success, + * -ETIME when the event is in the past. + */ +int clockevents_update_freq(struct clock_event_device *dev, u32 freq) +{ + clockevents_config(dev, freq); + + if (dev->mode != CLOCK_EVT_MODE_ONESHOT) + return 0; + + return clockevents_program_event(dev, dev->next_event, ktime_get()); +} + /* * Noop handler when we shut down an event device */ -- cgit v1.1 From 80d02085d99039b3b7f3a73c8896226b0cb1ba07 Mon Sep 17 00:00:00 2001 From: "Paul E. McKenney" Date: Thu, 12 May 2011 01:08:07 -0700 Subject: Revert "rcu: Decrease memory-barrier usage based on semi-formal proof" This reverts commit e59fb3120becfb36b22ddb8bd27d065d3cdca499. This reversion was due to (extreme) boot-time slowdowns on SPARC seen by Yinghai Lu and on x86 by Ingo . This is a non-trivial reversion due to intervening commits. Conflicts: Documentation/RCU/trace.txt kernel/rcutree.c Signed-off-by: Ingo Molnar --- kernel/rcutree.c | 130 +++++++++++++++++++++++++++--------------------- kernel/rcutree.h | 9 ++-- kernel/rcutree_plugin.h | 7 +-- kernel/rcutree_trace.c | 12 ++--- 4 files changed, 90 insertions(+), 68 deletions(-) (limited to 'kernel') diff --git a/kernel/rcutree.c b/kernel/rcutree.c index 5616b17..e486f7c 100644 --- a/kernel/rcutree.c +++ b/kernel/rcutree.c @@ -162,7 +162,7 @@ EXPORT_SYMBOL_GPL(rcu_note_context_switch); #ifdef CONFIG_NO_HZ DEFINE_PER_CPU(struct rcu_dynticks, rcu_dynticks) = { .dynticks_nesting = 1, - .dynticks = ATOMIC_INIT(1), + .dynticks = 1, }; #endif /* #ifdef CONFIG_NO_HZ */ @@ -321,25 +321,13 @@ void rcu_enter_nohz(void) unsigned long flags; struct rcu_dynticks *rdtp; + smp_mb(); /* CPUs seeing ++ must see prior RCU read-side crit sects */ local_irq_save(flags); rdtp = &__get_cpu_var(rcu_dynticks); - if (--rdtp->dynticks_nesting) { - local_irq_restore(flags); - return; - } - /* CPUs seeing atomic_inc() must see prior RCU read-side crit sects */ - smp_mb__before_atomic_inc(); /* See above. */ - atomic_inc(&rdtp->dynticks); - smp_mb__after_atomic_inc(); /* Force ordering with next sojourn. */ - WARN_ON_ONCE(atomic_read(&rdtp->dynticks) & 0x1); + rdtp->dynticks++; + rdtp->dynticks_nesting--; + WARN_ON_ONCE(rdtp->dynticks & 0x1); local_irq_restore(flags); - - /* If the interrupt queued a callback, get out of dyntick mode. */ - if (in_irq() && - (__get_cpu_var(rcu_sched_data).nxtlist || - __get_cpu_var(rcu_bh_data).nxtlist || - rcu_preempt_needs_cpu(smp_processor_id()))) - set_need_resched(); } /* @@ -355,16 +343,11 @@ void rcu_exit_nohz(void) local_irq_save(flags); rdtp = &__get_cpu_var(rcu_dynticks); - if (rdtp->dynticks_nesting++) { - local_irq_restore(flags); - return; - } - smp_mb__before_atomic_inc(); /* Force ordering w/previous sojourn. */ - atomic_inc(&rdtp->dynticks); - /* CPUs seeing atomic_inc() must see later RCU read-side crit sects */ - smp_mb__after_atomic_inc(); /* See above. */ - WARN_ON_ONCE(!(atomic_read(&rdtp->dynticks) & 0x1)); + rdtp->dynticks++; + rdtp->dynticks_nesting++; + WARN_ON_ONCE(!(rdtp->dynticks & 0x1)); local_irq_restore(flags); + smp_mb(); /* CPUs seeing ++ must see later RCU read-side crit sects */ } /** @@ -378,15 +361,11 @@ void rcu_nmi_enter(void) { struct rcu_dynticks *rdtp = &__get_cpu_var(rcu_dynticks); - if (rdtp->dynticks_nmi_nesting == 0 && - (atomic_read(&rdtp->dynticks) & 0x1)) + if (rdtp->dynticks & 0x1) return; - rdtp->dynticks_nmi_nesting++; - smp_mb__before_atomic_inc(); /* Force delay from prior write. */ - atomic_inc(&rdtp->dynticks); - /* CPUs seeing atomic_inc() must see later RCU read-side crit sects */ - smp_mb__after_atomic_inc(); /* See above. */ - WARN_ON_ONCE(!(atomic_read(&rdtp->dynticks) & 0x1)); + rdtp->dynticks_nmi++; + WARN_ON_ONCE(!(rdtp->dynticks_nmi & 0x1)); + smp_mb(); /* CPUs seeing ++ must see later RCU read-side crit sects */ } /** @@ -400,14 +379,11 @@ void rcu_nmi_exit(void) { struct rcu_dynticks *rdtp = &__get_cpu_var(rcu_dynticks); - if (rdtp->dynticks_nmi_nesting == 0 || - --rdtp->dynticks_nmi_nesting != 0) + if (rdtp->dynticks & 0x1) return; - /* CPUs seeing atomic_inc() must see prior RCU read-side crit sects */ - smp_mb__before_atomic_inc(); /* See above. */ - atomic_inc(&rdtp->dynticks); - smp_mb__after_atomic_inc(); /* Force delay to next write. */ - WARN_ON_ONCE(atomic_read(&rdtp->dynticks) & 0x1); + smp_mb(); /* CPUs seeing ++ must see prior RCU read-side crit sects */ + rdtp->dynticks_nmi++; + WARN_ON_ONCE(rdtp->dynticks_nmi & 0x1); } /** @@ -418,7 +394,13 @@ void rcu_nmi_exit(void) */ void rcu_irq_enter(void) { - rcu_exit_nohz(); + struct rcu_dynticks *rdtp = &__get_cpu_var(rcu_dynticks); + + if (rdtp->dynticks_nesting++) + return; + rdtp->dynticks++; + WARN_ON_ONCE(!(rdtp->dynticks & 0x1)); + smp_mb(); /* CPUs seeing ++ must see later RCU read-side crit sects */ } /** @@ -430,7 +412,18 @@ void rcu_irq_enter(void) */ void rcu_irq_exit(void) { - rcu_enter_nohz(); + struct rcu_dynticks *rdtp = &__get_cpu_var(rcu_dynticks); + + if (--rdtp->dynticks_nesting) + return; + smp_mb(); /* CPUs seeing ++ must see prior RCU read-side crit sects */ + rdtp->dynticks++; + WARN_ON_ONCE(rdtp->dynticks & 0x1); + + /* If the interrupt queued a callback, get out of dyntick mode. */ + if (__this_cpu_read(rcu_sched_data.nxtlist) || + __this_cpu_read(rcu_bh_data.nxtlist)) + set_need_resched(); } #ifdef CONFIG_SMP @@ -442,8 +435,19 @@ void rcu_irq_exit(void) */ static int dyntick_save_progress_counter(struct rcu_data *rdp) { - rdp->dynticks_snap = atomic_add_return(0, &rdp->dynticks->dynticks); - return 0; + int ret; + int snap; + int snap_nmi; + + snap = rdp->dynticks->dynticks; + snap_nmi = rdp->dynticks->dynticks_nmi; + smp_mb(); /* Order sampling of snap with end of grace period. */ + rdp->dynticks_snap = snap; + rdp->dynticks_nmi_snap = snap_nmi; + ret = ((snap & 0x1) == 0) && ((snap_nmi & 0x1) == 0); + if (ret) + rdp->dynticks_fqs++; + return ret; } /* @@ -454,11 +458,16 @@ static int dyntick_save_progress_counter(struct rcu_data *rdp) */ static int rcu_implicit_dynticks_qs(struct rcu_data *rdp) { - unsigned long curr; - unsigned long snap; + long curr; + long curr_nmi; + long snap; + long snap_nmi; - curr = (unsigned long)atomic_add_return(0, &rdp->dynticks->dynticks); - snap = (unsigned long)rdp->dynticks_snap; + curr = rdp->dynticks->dynticks; + snap = rdp->dynticks_snap; + curr_nmi = rdp->dynticks->dynticks_nmi; + snap_nmi = rdp->dynticks_nmi_snap; + smp_mb(); /* force ordering with cpu entering/leaving dynticks. */ /* * If the CPU passed through or entered a dynticks idle phase with @@ -468,7 +477,8 @@ static int rcu_implicit_dynticks_qs(struct rcu_data *rdp) * read-side critical section that started before the beginning * of the current RCU grace period. */ - if ((curr & 0x1) == 0 || ULONG_CMP_GE(curr, snap + 2)) { + if ((curr != snap || (curr & 0x1) == 0) && + (curr_nmi != snap_nmi || (curr_nmi & 0x1) == 0)) { rdp->dynticks_fqs++; return 1; } @@ -897,12 +907,6 @@ static void rcu_report_qs_rsp(struct rcu_state *rsp, unsigned long flags) unsigned long gp_duration; WARN_ON_ONCE(!rcu_gp_in_progress(rsp)); - - /* - * Ensure that all grace-period and pre-grace-period activity - * is seen before the assignment to rsp->completed. - */ - smp_mb(); /* See above block comment. */ gp_duration = jiffies - rsp->gp_start; if (gp_duration > rsp->gp_max) rsp->gp_max = gp_duration; @@ -1450,11 +1454,25 @@ __rcu_process_callbacks(struct rcu_state *rsp, struct rcu_data *rdp) */ static void rcu_process_callbacks(void) { + /* + * Memory references from any prior RCU read-side critical sections + * executed by the interrupted code must be seen before any RCU + * grace-period manipulations below. + */ + smp_mb(); /* See above block comment. */ + __rcu_process_callbacks(&rcu_sched_state, &__get_cpu_var(rcu_sched_data)); __rcu_process_callbacks(&rcu_bh_state, &__get_cpu_var(rcu_bh_data)); rcu_preempt_process_callbacks(); + /* + * Memory references from any later RCU read-side critical sections + * executed by the interrupted code must be seen after any RCU + * grace-period manipulations above. + */ + smp_mb(); /* See above block comment. */ + /* If we are last CPU on way to dyntick-idle mode, accelerate it. */ rcu_needs_cpu_flush(); } diff --git a/kernel/rcutree.h b/kernel/rcutree.h index 93d4a1c..2576648 100644 --- a/kernel/rcutree.h +++ b/kernel/rcutree.h @@ -84,9 +84,11 @@ * Dynticks per-CPU state. */ struct rcu_dynticks { - int dynticks_nesting; /* Track irq/process nesting level. */ - int dynticks_nmi_nesting; /* Track NMI nesting level. */ - atomic_t dynticks; /* Even value for dynticks-idle, else odd. */ + int dynticks_nesting; /* Track nesting level, sort of. */ + int dynticks; /* Even value for dynticks-idle, else odd. */ + int dynticks_nmi; /* Even value for either dynticks-idle or */ + /* not in nmi handler, else odd. So this */ + /* remains even for nmi from irq handler. */ }; /* RCU's kthread states for tracing. */ @@ -282,6 +284,7 @@ struct rcu_data { /* 3) dynticks interface. */ struct rcu_dynticks *dynticks; /* Shared per-CPU dynticks state. */ int dynticks_snap; /* Per-GP tracking for dynticks. */ + int dynticks_nmi_snap; /* Per-GP tracking for dynticks_nmi. */ #endif /* #ifdef CONFIG_NO_HZ */ /* 4) reasons this CPU needed to be kicked by force_quiescent_state */ diff --git a/kernel/rcutree_plugin.h b/kernel/rcutree_plugin.h index ed339702..3f6559a 100644 --- a/kernel/rcutree_plugin.h +++ b/kernel/rcutree_plugin.h @@ -1520,6 +1520,7 @@ int rcu_needs_cpu(int cpu) { int c = 0; int snap; + int snap_nmi; int thatcpu; /* Check for being in the holdoff period. */ @@ -1530,10 +1531,10 @@ int rcu_needs_cpu(int cpu) for_each_online_cpu(thatcpu) { if (thatcpu == cpu) continue; - snap = atomic_add_return(0, &per_cpu(rcu_dynticks, - thatcpu).dynticks); + snap = per_cpu(rcu_dynticks, thatcpu).dynticks; + snap_nmi = per_cpu(rcu_dynticks, thatcpu).dynticks_nmi; smp_mb(); /* Order sampling of snap with end of grace period. */ - if ((snap & 0x1) != 0) { + if (((snap & 0x1) != 0) || ((snap_nmi & 0x1) != 0)) { per_cpu(rcu_dyntick_drain, cpu) = 0; per_cpu(rcu_dyntick_holdoff, cpu) = jiffies - 1; return rcu_needs_cpu_quick_check(cpu); diff --git a/kernel/rcutree_trace.c b/kernel/rcutree_trace.c index 9678cc3..aa0fd72 100644 --- a/kernel/rcutree_trace.c +++ b/kernel/rcutree_trace.c @@ -69,10 +69,10 @@ static void print_one_rcu_data(struct seq_file *m, struct rcu_data *rdp) rdp->passed_quiesc, rdp->passed_quiesc_completed, rdp->qs_pending); #ifdef CONFIG_NO_HZ - seq_printf(m, " dt=%d/%d/%d df=%lu", - atomic_read(&rdp->dynticks->dynticks), + seq_printf(m, " dt=%d/%d dn=%d df=%lu", + rdp->dynticks->dynticks, rdp->dynticks->dynticks_nesting, - rdp->dynticks->dynticks_nmi_nesting, + rdp->dynticks->dynticks_nmi, rdp->dynticks_fqs); #endif /* #ifdef CONFIG_NO_HZ */ seq_printf(m, " of=%lu ri=%lu", rdp->offline_fqs, rdp->resched_ipi); @@ -141,9 +141,9 @@ static void print_one_rcu_data_csv(struct seq_file *m, struct rcu_data *rdp) rdp->qs_pending); #ifdef CONFIG_NO_HZ seq_printf(m, ",%d,%d,%d,%lu", - atomic_read(&rdp->dynticks->dynticks), + rdp->dynticks->dynticks, rdp->dynticks->dynticks_nesting, - rdp->dynticks->dynticks_nmi_nesting, + rdp->dynticks->dynticks_nmi, rdp->dynticks_fqs); #endif /* #ifdef CONFIG_NO_HZ */ seq_printf(m, ",%lu,%lu", rdp->offline_fqs, rdp->resched_ipi); @@ -167,7 +167,7 @@ static int show_rcudata_csv(struct seq_file *m, void *unused) { seq_puts(m, "\"CPU\",\"Online?\",\"c\",\"g\",\"pq\",\"pqc\",\"pq\","); #ifdef CONFIG_NO_HZ - seq_puts(m, "\"dt\",\"dt nesting\",\"dt NMI nesting\",\"df\","); + seq_puts(m, "\"dt\",\"dt nesting\",\"dn\",\"df\","); #endif /* #ifdef CONFIG_NO_HZ */ seq_puts(m, "\"of\",\"ri\",\"ql\",\"b\",\"ci\",\"co\",\"ca\"\n"); #ifdef CONFIG_TREE_PREEMPT_RCU -- cgit v1.1 From c0e299b1a91cbdb21ae08e382a4176200398bc36 Mon Sep 17 00:00:00 2001 From: Thomas Gleixner Date: Fri, 20 May 2011 10:50:52 +0200 Subject: clockevents/source: Use u64 to make 32bit happy unsigned long is not 64bit on 32bit machine. Signed-off-by: Thomas Gleixner --- kernel/time/clockevents.c | 2 +- kernel/time/clocksource.c | 2 +- 2 files changed, 2 insertions(+), 2 deletions(-) (limited to 'kernel') diff --git a/kernel/time/clockevents.c b/kernel/time/clockevents.c index 22a9da9..c027d4f 100644 --- a/kernel/time/clockevents.c +++ b/kernel/time/clockevents.c @@ -197,7 +197,7 @@ EXPORT_SYMBOL_GPL(clockevents_register_device); static void clockevents_config(struct clock_event_device *dev, u32 freq) { - unsigned long sec; + u64 sec; if (!(dev->features & CLOCK_EVT_FEAT_ONESHOT)) return; diff --git a/kernel/time/clocksource.c b/kernel/time/clocksource.c index d9d5f8c..1c95fd6 100644 --- a/kernel/time/clocksource.c +++ b/kernel/time/clocksource.c @@ -639,7 +639,7 @@ static void clocksource_enqueue(struct clocksource *cs) */ void __clocksource_updatefreq_scale(struct clocksource *cs, u32 scale, u32 freq) { - unsigned long sec; + u64 sec; /* * Calc the maximum number of seconds which we can run before -- cgit v1.1