diff options
Diffstat (limited to 'kernel')
-rw-r--r-- | kernel/acct.c | 17 | ||||
-rw-r--r-- | kernel/cgroup.c | 62 | ||||
-rw-r--r-- | kernel/fork.c | 1 | ||||
-rw-r--r-- | kernel/kexec.c | 6 | ||||
-rw-r--r-- | kernel/lockdep.c | 84 | ||||
-rw-r--r-- | kernel/lockdep_internals.h | 72 | ||||
-rw-r--r-- | kernel/lockdep_proc.c | 58 | ||||
-rw-r--r-- | kernel/perf_event.c | 389 | ||||
-rw-r--r-- | kernel/profile.c | 4 | ||||
-rw-r--r-- | kernel/ptrace.c | 11 | ||||
-rw-r--r-- | kernel/rcupdate.c | 30 | ||||
-rw-r--r-- | kernel/rcutiny.c | 35 | ||||
-rw-r--r-- | kernel/rcutiny_plugin.h | 39 | ||||
-rw-r--r-- | kernel/rcutorture.c | 2 | ||||
-rw-r--r-- | kernel/rcutree.c | 131 | ||||
-rw-r--r-- | kernel/rcutree.h | 2 | ||||
-rw-r--r-- | kernel/rcutree_plugin.h | 69 | ||||
-rw-r--r-- | kernel/rcutree_trace.c | 4 | ||||
-rw-r--r-- | kernel/sched.c | 2 | ||||
-rw-r--r-- | kernel/sched_debug.c | 2 | ||||
-rw-r--r-- | kernel/softirq.c | 2 | ||||
-rw-r--r-- | kernel/stop_machine.c | 5 | ||||
-rw-r--r-- | kernel/trace/trace_event_perf.c | 190 | ||||
-rw-r--r-- | kernel/trace/trace_kprobe.c | 17 | ||||
-rw-r--r-- | kernel/trace/trace_syscalls.c | 17 |
25 files changed, 762 insertions, 489 deletions
diff --git a/kernel/acct.c b/kernel/acct.c index 24f8c81..e4c0e1f 100644 --- a/kernel/acct.c +++ b/kernel/acct.c @@ -353,17 +353,18 @@ restart: void acct_exit_ns(struct pid_namespace *ns) { - struct bsd_acct_struct *acct; + struct bsd_acct_struct *acct = ns->bacct; - spin_lock(&acct_lock); - acct = ns->bacct; - if (acct != NULL) { - if (acct->file != NULL) - acct_file_reopen(acct, NULL, NULL); + if (acct == NULL) + return; - kfree(acct); - } + del_timer_sync(&acct->timer); + spin_lock(&acct_lock); + if (acct->file != NULL) + acct_file_reopen(acct, NULL, NULL); spin_unlock(&acct_lock); + + kfree(acct); } /* diff --git a/kernel/cgroup.c b/kernel/cgroup.c index 4a07d05..e9ec642 100644 --- a/kernel/cgroup.c +++ b/kernel/cgroup.c @@ -1646,7 +1646,9 @@ static inline struct cftype *__d_cft(struct dentry *dentry) int cgroup_path(const struct cgroup *cgrp, char *buf, int buflen) { char *start; - struct dentry *dentry = rcu_dereference(cgrp->dentry); + struct dentry *dentry = rcu_dereference_check(cgrp->dentry, + rcu_read_lock_held() || + cgroup_lock_is_held()); if (!dentry || cgrp == dummytop) { /* @@ -1662,13 +1664,17 @@ int cgroup_path(const struct cgroup *cgrp, char *buf, int buflen) *--start = '\0'; for (;;) { int len = dentry->d_name.len; + if ((start -= len) < buf) return -ENAMETOOLONG; - memcpy(start, cgrp->dentry->d_name.name, len); + memcpy(start, dentry->d_name.name, len); cgrp = cgrp->parent; if (!cgrp) break; - dentry = rcu_dereference(cgrp->dentry); + + dentry = rcu_dereference_check(cgrp->dentry, + rcu_read_lock_held() || + cgroup_lock_is_held()); if (!cgrp->parent) continue; if (--start < buf) @@ -4429,7 +4435,15 @@ __setup("cgroup_disable=", cgroup_disable); */ unsigned short css_id(struct cgroup_subsys_state *css) { - struct css_id *cssid = rcu_dereference(css->id); + struct css_id *cssid; + + /* + * This css_id() can return correct value when somone has refcnt + * on this or this is under rcu_read_lock(). Once css->id is allocated, + * it's unchanged until freed. + */ + cssid = rcu_dereference_check(css->id, + rcu_read_lock_held() || atomic_read(&css->refcnt)); if (cssid) return cssid->id; @@ -4439,7 +4453,10 @@ EXPORT_SYMBOL_GPL(css_id); unsigned short css_depth(struct cgroup_subsys_state *css) { - struct css_id *cssid = rcu_dereference(css->id); + struct css_id *cssid; + + cssid = rcu_dereference_check(css->id, + rcu_read_lock_held() || atomic_read(&css->refcnt)); if (cssid) return cssid->depth; @@ -4447,15 +4464,36 @@ unsigned short css_depth(struct cgroup_subsys_state *css) } EXPORT_SYMBOL_GPL(css_depth); +/** + * css_is_ancestor - test "root" css is an ancestor of "child" + * @child: the css to be tested. + * @root: the css supporsed to be an ancestor of the child. + * + * Returns true if "root" is an ancestor of "child" in its hierarchy. Because + * this function reads css->id, this use rcu_dereference() and rcu_read_lock(). + * But, considering usual usage, the csses should be valid objects after test. + * Assuming that the caller will do some action to the child if this returns + * returns true, the caller must take "child";s reference count. + * If "child" is valid object and this returns true, "root" is valid, too. + */ + bool css_is_ancestor(struct cgroup_subsys_state *child, const struct cgroup_subsys_state *root) { - struct css_id *child_id = rcu_dereference(child->id); - struct css_id *root_id = rcu_dereference(root->id); + struct css_id *child_id; + struct css_id *root_id; + bool ret = true; - if (!child_id || !root_id || (child_id->depth < root_id->depth)) - return false; - return child_id->stack[root_id->depth] == root_id->id; + rcu_read_lock(); + child_id = rcu_dereference(child->id); + root_id = rcu_dereference(root->id); + if (!child_id + || !root_id + || (child_id->depth < root_id->depth) + || (child_id->stack[root_id->depth] != root_id->id)) + ret = false; + rcu_read_unlock(); + return ret; } static void __free_css_id_cb(struct rcu_head *head) @@ -4555,13 +4593,13 @@ static int alloc_css_id(struct cgroup_subsys *ss, struct cgroup *parent, { int subsys_id, i, depth = 0; struct cgroup_subsys_state *parent_css, *child_css; - struct css_id *child_id, *parent_id = NULL; + struct css_id *child_id, *parent_id; subsys_id = ss->subsys_id; parent_css = parent->subsys[subsys_id]; child_css = child->subsys[subsys_id]; - depth = css_depth(parent_css) + 1; parent_id = parent_css->id; + depth = parent_id->depth; child_id = get_new_cssid(ss, depth); if (IS_ERR(child_id)) diff --git a/kernel/fork.c b/kernel/fork.c index 5d3592de..4d57d9e 100644 --- a/kernel/fork.c +++ b/kernel/fork.c @@ -1111,7 +1111,6 @@ static struct task_struct *copy_process(unsigned long clone_flags, p->memcg_batch.do_batch = 0; p->memcg_batch.memcg = NULL; #endif - p->stack_start = stack_start; /* Perform scheduler related setup. Assign this task to a CPU. */ sched_fork(p, clone_flags); diff --git a/kernel/kexec.c b/kernel/kexec.c index 87ebe8a..474a847 100644 --- a/kernel/kexec.c +++ b/kernel/kexec.c @@ -1134,11 +1134,9 @@ int crash_shrink_memory(unsigned long new_size) free_reserved_phys_range(end, crashk_res.end); - if (start == end) { - crashk_res.end = end; + if (start == end) release_resource(&crashk_res); - } else - crashk_res.end = end - 1; + crashk_res.end = end - 1; unlock: mutex_unlock(&kexec_mutex); diff --git a/kernel/lockdep.c b/kernel/lockdep.c index e9c759f..ec21304 100644 --- a/kernel/lockdep.c +++ b/kernel/lockdep.c @@ -431,20 +431,7 @@ static struct stack_trace lockdep_init_trace = { /* * Various lockdep statistics: */ -atomic_t chain_lookup_hits; -atomic_t chain_lookup_misses; -atomic_t hardirqs_on_events; -atomic_t hardirqs_off_events; -atomic_t redundant_hardirqs_on; -atomic_t redundant_hardirqs_off; -atomic_t softirqs_on_events; -atomic_t softirqs_off_events; -atomic_t redundant_softirqs_on; -atomic_t redundant_softirqs_off; -atomic_t nr_unused_locks; -atomic_t nr_cyclic_checks; -atomic_t nr_find_usage_forwards_checks; -atomic_t nr_find_usage_backwards_checks; +DEFINE_PER_CPU(struct lockdep_stats, lockdep_stats); #endif /* @@ -748,7 +735,7 @@ register_lock_class(struct lockdep_map *lock, unsigned int subclass, int force) return NULL; } class = lock_classes + nr_lock_classes++; - debug_atomic_inc(&nr_unused_locks); + debug_atomic_inc(nr_unused_locks); class->key = key; class->name = lock->name; class->subclass = subclass; @@ -818,7 +805,8 @@ static struct lock_list *alloc_list_entry(void) * Add a new dependency to the head of the list: */ static int add_lock_to_list(struct lock_class *class, struct lock_class *this, - struct list_head *head, unsigned long ip, int distance) + struct list_head *head, unsigned long ip, + int distance, struct stack_trace *trace) { struct lock_list *entry; /* @@ -829,11 +817,9 @@ static int add_lock_to_list(struct lock_class *class, struct lock_class *this, if (!entry) return 0; - if (!save_trace(&entry->trace)) - return 0; - entry->class = this; entry->distance = distance; + entry->trace = *trace; /* * Since we never remove from the dependency list, the list can * be walked lockless by other CPUs, it's only allocation @@ -1205,7 +1191,7 @@ check_noncircular(struct lock_list *root, struct lock_class *target, { int result; - debug_atomic_inc(&nr_cyclic_checks); + debug_atomic_inc(nr_cyclic_checks); result = __bfs_forwards(root, target, class_equal, target_entry); @@ -1242,7 +1228,7 @@ find_usage_forwards(struct lock_list *root, enum lock_usage_bit bit, { int result; - debug_atomic_inc(&nr_find_usage_forwards_checks); + debug_atomic_inc(nr_find_usage_forwards_checks); result = __bfs_forwards(root, (void *)bit, usage_match, target_entry); @@ -1265,7 +1251,7 @@ find_usage_backwards(struct lock_list *root, enum lock_usage_bit bit, { int result; - debug_atomic_inc(&nr_find_usage_backwards_checks); + debug_atomic_inc(nr_find_usage_backwards_checks); result = __bfs_backwards(root, (void *)bit, usage_match, target_entry); @@ -1635,12 +1621,20 @@ check_deadlock(struct task_struct *curr, struct held_lock *next, */ static int check_prev_add(struct task_struct *curr, struct held_lock *prev, - struct held_lock *next, int distance) + struct held_lock *next, int distance, int trylock_loop) { struct lock_list *entry; int ret; struct lock_list this; struct lock_list *uninitialized_var(target_entry); + /* + * Static variable, serialized by the graph_lock(). + * + * We use this static variable to save the stack trace in case + * we call into this function multiple times due to encountering + * trylocks in the held lock stack. + */ + static struct stack_trace trace; /* * Prove that the new <prev> -> <next> dependency would not @@ -1688,20 +1682,23 @@ check_prev_add(struct task_struct *curr, struct held_lock *prev, } } + if (!trylock_loop && !save_trace(&trace)) + return 0; + /* * Ok, all validations passed, add the new lock * to the previous lock's dependency list: */ ret = add_lock_to_list(hlock_class(prev), hlock_class(next), &hlock_class(prev)->locks_after, - next->acquire_ip, distance); + next->acquire_ip, distance, &trace); if (!ret) return 0; ret = add_lock_to_list(hlock_class(next), hlock_class(prev), &hlock_class(next)->locks_before, - next->acquire_ip, distance); + next->acquire_ip, distance, &trace); if (!ret) return 0; @@ -1731,6 +1728,7 @@ static int check_prevs_add(struct task_struct *curr, struct held_lock *next) { int depth = curr->lockdep_depth; + int trylock_loop = 0; struct held_lock *hlock; /* @@ -1756,7 +1754,8 @@ check_prevs_add(struct task_struct *curr, struct held_lock *next) * added: */ if (hlock->read != 2) { - if (!check_prev_add(curr, hlock, next, distance)) + if (!check_prev_add(curr, hlock, next, + distance, trylock_loop)) return 0; /* * Stop after the first non-trylock entry, @@ -1779,6 +1778,7 @@ check_prevs_add(struct task_struct *curr, struct held_lock *next) if (curr->held_locks[depth].irq_context != curr->held_locks[depth-1].irq_context) break; + trylock_loop = 1; } return 1; out_bug: @@ -1825,7 +1825,7 @@ static inline int lookup_chain_cache(struct task_struct *curr, list_for_each_entry(chain, hash_head, entry) { if (chain->chain_key == chain_key) { cache_hit: - debug_atomic_inc(&chain_lookup_hits); + debug_atomic_inc(chain_lookup_hits); if (very_verbose(class)) printk("\nhash chain already cached, key: " "%016Lx tail class: [%p] %s\n", @@ -1890,7 +1890,7 @@ cache_hit: chain_hlocks[chain->base + j] = class - lock_classes; } list_add_tail_rcu(&chain->entry, hash_head); - debug_atomic_inc(&chain_lookup_misses); + debug_atomic_inc(chain_lookup_misses); inc_chains(); return 1; @@ -2311,7 +2311,12 @@ void trace_hardirqs_on_caller(unsigned long ip) return; if (unlikely(curr->hardirqs_enabled)) { - debug_atomic_inc(&redundant_hardirqs_on); + /* + * Neither irq nor preemption are disabled here + * so this is racy by nature but loosing one hit + * in a stat is not a big deal. + */ + __debug_atomic_inc(redundant_hardirqs_on); return; } /* we'll do an OFF -> ON transition: */ @@ -2338,7 +2343,7 @@ void trace_hardirqs_on_caller(unsigned long ip) curr->hardirq_enable_ip = ip; curr->hardirq_enable_event = ++curr->irq_events; - debug_atomic_inc(&hardirqs_on_events); + debug_atomic_inc(hardirqs_on_events); } EXPORT_SYMBOL(trace_hardirqs_on_caller); @@ -2370,9 +2375,9 @@ void trace_hardirqs_off_caller(unsigned long ip) curr->hardirqs_enabled = 0; curr->hardirq_disable_ip = ip; curr->hardirq_disable_event = ++curr->irq_events; - debug_atomic_inc(&hardirqs_off_events); + debug_atomic_inc(hardirqs_off_events); } else - debug_atomic_inc(&redundant_hardirqs_off); + debug_atomic_inc(redundant_hardirqs_off); } EXPORT_SYMBOL(trace_hardirqs_off_caller); @@ -2396,7 +2401,7 @@ void trace_softirqs_on(unsigned long ip) return; if (curr->softirqs_enabled) { - debug_atomic_inc(&redundant_softirqs_on); + debug_atomic_inc(redundant_softirqs_on); return; } @@ -2406,7 +2411,7 @@ void trace_softirqs_on(unsigned long ip) curr->softirqs_enabled = 1; curr->softirq_enable_ip = ip; curr->softirq_enable_event = ++curr->irq_events; - debug_atomic_inc(&softirqs_on_events); + debug_atomic_inc(softirqs_on_events); /* * We are going to turn softirqs on, so set the * usage bit for all held locks, if hardirqs are @@ -2436,10 +2441,10 @@ void trace_softirqs_off(unsigned long ip) curr->softirqs_enabled = 0; curr->softirq_disable_ip = ip; curr->softirq_disable_event = ++curr->irq_events; - debug_atomic_inc(&softirqs_off_events); + debug_atomic_inc(softirqs_off_events); DEBUG_LOCKS_WARN_ON(!softirq_count()); } else - debug_atomic_inc(&redundant_softirqs_off); + debug_atomic_inc(redundant_softirqs_off); } static void __lockdep_trace_alloc(gfp_t gfp_mask, unsigned long flags) @@ -2644,7 +2649,7 @@ static int mark_lock(struct task_struct *curr, struct held_lock *this, return 0; break; case LOCK_USED: - debug_atomic_dec(&nr_unused_locks); + debug_atomic_dec(nr_unused_locks); break; default: if (!debug_locks_off_graph_unlock()) @@ -2750,7 +2755,7 @@ static int __lock_acquire(struct lockdep_map *lock, unsigned int subclass, if (!class) return 0; } - debug_atomic_inc((atomic_t *)&class->ops); + atomic_inc((atomic_t *)&class->ops); if (very_verbose(class)) { printk("\nacquire class [%p] %s", class->key, class->name); if (class->name_version > 1) @@ -3801,8 +3806,11 @@ void lockdep_rcu_dereference(const char *file, const int line) { struct task_struct *curr = current; +#ifndef CONFIG_PROVE_RCU_REPEATEDLY if (!debug_locks_off()) return; +#endif /* #ifdef CONFIG_PROVE_RCU_REPEATEDLY */ + /* Note: the following can be executed concurrently, so be careful. */ printk("\n===================================================\n"); printk( "[ INFO: suspicious rcu_dereference_check() usage. ]\n"); printk( "---------------------------------------------------\n"); diff --git a/kernel/lockdep_internals.h b/kernel/lockdep_internals.h index a2ee95a..4f560cf 100644 --- a/kernel/lockdep_internals.h +++ b/kernel/lockdep_internals.h @@ -110,30 +110,60 @@ lockdep_count_backward_deps(struct lock_class *class) #endif #ifdef CONFIG_DEBUG_LOCKDEP + +#include <asm/local.h> /* - * Various lockdep statistics: + * Various lockdep statistics. + * We want them per cpu as they are often accessed in fast path + * and we want to avoid too much cache bouncing. */ -extern atomic_t chain_lookup_hits; -extern atomic_t chain_lookup_misses; -extern atomic_t hardirqs_on_events; -extern atomic_t hardirqs_off_events; -extern atomic_t redundant_hardirqs_on; -extern atomic_t redundant_hardirqs_off; -extern atomic_t softirqs_on_events; -extern atomic_t softirqs_off_events; -extern atomic_t redundant_softirqs_on; -extern atomic_t redundant_softirqs_off; -extern atomic_t nr_unused_locks; -extern atomic_t nr_cyclic_checks; -extern atomic_t nr_cyclic_check_recursions; -extern atomic_t nr_find_usage_forwards_checks; -extern atomic_t nr_find_usage_forwards_recursions; -extern atomic_t nr_find_usage_backwards_checks; -extern atomic_t nr_find_usage_backwards_recursions; -# define debug_atomic_inc(ptr) atomic_inc(ptr) -# define debug_atomic_dec(ptr) atomic_dec(ptr) -# define debug_atomic_read(ptr) atomic_read(ptr) +struct lockdep_stats { + int chain_lookup_hits; + int chain_lookup_misses; + int hardirqs_on_events; + int hardirqs_off_events; + int redundant_hardirqs_on; + int redundant_hardirqs_off; + int softirqs_on_events; + int softirqs_off_events; + int redundant_softirqs_on; + int redundant_softirqs_off; + int nr_unused_locks; + int nr_cyclic_checks; + int nr_cyclic_check_recursions; + int nr_find_usage_forwards_checks; + int nr_find_usage_forwards_recursions; + int nr_find_usage_backwards_checks; + int nr_find_usage_backwards_recursions; +}; + +DECLARE_PER_CPU(struct lockdep_stats, lockdep_stats); + +#define __debug_atomic_inc(ptr) \ + this_cpu_inc(lockdep_stats.ptr); + +#define debug_atomic_inc(ptr) { \ + WARN_ON_ONCE(!irqs_disabled()); \ + __this_cpu_inc(lockdep_stats.ptr); \ +} + +#define debug_atomic_dec(ptr) { \ + WARN_ON_ONCE(!irqs_disabled()); \ + __this_cpu_dec(lockdep_stats.ptr); \ +} + +#define debug_atomic_read(ptr) ({ \ + struct lockdep_stats *__cpu_lockdep_stats; \ + unsigned long long __total = 0; \ + int __cpu; \ + for_each_possible_cpu(__cpu) { \ + __cpu_lockdep_stats = &per_cpu(lockdep_stats, __cpu); \ + __total += __cpu_lockdep_stats->ptr; \ + } \ + __total; \ +}) #else +# define __debug_atomic_inc(ptr) do { } while (0) # define debug_atomic_inc(ptr) do { } while (0) # define debug_atomic_dec(ptr) do { } while (0) # define debug_atomic_read(ptr) 0 diff --git a/kernel/lockdep_proc.c b/kernel/lockdep_proc.c index d4aba4f..59b76c8 100644 --- a/kernel/lockdep_proc.c +++ b/kernel/lockdep_proc.c @@ -184,34 +184,34 @@ static const struct file_operations proc_lockdep_chains_operations = { static void lockdep_stats_debug_show(struct seq_file *m) { #ifdef CONFIG_DEBUG_LOCKDEP - unsigned int hi1 = debug_atomic_read(&hardirqs_on_events), - hi2 = debug_atomic_read(&hardirqs_off_events), - hr1 = debug_atomic_read(&redundant_hardirqs_on), - hr2 = debug_atomic_read(&redundant_hardirqs_off), - si1 = debug_atomic_read(&softirqs_on_events), - si2 = debug_atomic_read(&softirqs_off_events), - sr1 = debug_atomic_read(&redundant_softirqs_on), - sr2 = debug_atomic_read(&redundant_softirqs_off); - - seq_printf(m, " chain lookup misses: %11u\n", - debug_atomic_read(&chain_lookup_misses)); - seq_printf(m, " chain lookup hits: %11u\n", - debug_atomic_read(&chain_lookup_hits)); - seq_printf(m, " cyclic checks: %11u\n", - debug_atomic_read(&nr_cyclic_checks)); - seq_printf(m, " find-mask forwards checks: %11u\n", - debug_atomic_read(&nr_find_usage_forwards_checks)); - seq_printf(m, " find-mask backwards checks: %11u\n", - debug_atomic_read(&nr_find_usage_backwards_checks)); - - seq_printf(m, " hardirq on events: %11u\n", hi1); - seq_printf(m, " hardirq off events: %11u\n", hi2); - seq_printf(m, " redundant hardirq ons: %11u\n", hr1); - seq_printf(m, " redundant hardirq offs: %11u\n", hr2); - seq_printf(m, " softirq on events: %11u\n", si1); - seq_printf(m, " softirq off events: %11u\n", si2); - seq_printf(m, " redundant softirq ons: %11u\n", sr1); - seq_printf(m, " redundant softirq offs: %11u\n", sr2); + unsigned long long hi1 = debug_atomic_read(hardirqs_on_events), + hi2 = debug_atomic_read(hardirqs_off_events), + hr1 = debug_atomic_read(redundant_hardirqs_on), + hr2 = debug_atomic_read(redundant_hardirqs_off), + si1 = debug_atomic_read(softirqs_on_events), + si2 = debug_atomic_read(softirqs_off_events), + sr1 = debug_atomic_read(redundant_softirqs_on), + sr2 = debug_atomic_read(redundant_softirqs_off); + + seq_printf(m, " chain lookup misses: %11llu\n", + debug_atomic_read(chain_lookup_misses)); + seq_printf(m, " chain lookup hits: %11llu\n", + debug_atomic_read(chain_lookup_hits)); + seq_printf(m, " cyclic checks: %11llu\n", + debug_atomic_read(nr_cyclic_checks)); + seq_printf(m, " find-mask forwards checks: %11llu\n", + debug_atomic_read(nr_find_usage_forwards_checks)); + seq_printf(m, " find-mask backwards checks: %11llu\n", + debug_atomic_read(nr_find_usage_backwards_checks)); + + seq_printf(m, " hardirq on events: %11llu\n", hi1); + seq_printf(m, " hardirq off events: %11llu\n", hi2); + seq_printf(m, " redundant hardirq ons: %11llu\n", hr1); + seq_printf(m, " redundant hardirq offs: %11llu\n", hr2); + seq_printf(m, " softirq on events: %11llu\n", si1); + seq_printf(m, " softirq off events: %11llu\n", si2); + seq_printf(m, " redundant softirq ons: %11llu\n", sr1); + seq_printf(m, " redundant softirq offs: %11llu\n", sr2); #endif } @@ -263,7 +263,7 @@ static int lockdep_stats_show(struct seq_file *m, void *v) #endif } #ifdef CONFIG_DEBUG_LOCKDEP - DEBUG_LOCKS_WARN_ON(debug_atomic_read(&nr_unused_locks) != nr_unused); + DEBUG_LOCKS_WARN_ON(debug_atomic_read(nr_unused_locks) != nr_unused); #endif seq_printf(m, " lock-classes: %11lu [max: %lu]\n", nr_lock_classes, MAX_LOCKDEP_KEYS); diff --git a/kernel/perf_event.c b/kernel/perf_event.c index a4fa381..e099650 100644 --- a/kernel/perf_event.c +++ b/kernel/perf_event.c @@ -2297,11 +2297,6 @@ unlock: rcu_read_unlock(); } -static unsigned long perf_data_size(struct perf_mmap_data *data) -{ - return data->nr_pages << (PAGE_SHIFT + data->data_order); -} - #ifndef CONFIG_PERF_USE_VMALLOC /* @@ -2320,6 +2315,19 @@ perf_mmap_to_page(struct perf_mmap_data *data, unsigned long pgoff) return virt_to_page(data->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_mmap_data * perf_mmap_data_alloc(struct perf_event *event, int nr_pages) { @@ -2336,17 +2344,16 @@ perf_mmap_data_alloc(struct perf_event *event, int nr_pages) if (!data) goto fail; - data->user_page = (void *)get_zeroed_page(GFP_KERNEL); + data->user_page = perf_mmap_alloc_page(event->cpu); if (!data->user_page) goto fail_user_page; for (i = 0; i < nr_pages; i++) { - data->data_pages[i] = (void *)get_zeroed_page(GFP_KERNEL); + data->data_pages[i] = perf_mmap_alloc_page(event->cpu); if (!data->data_pages[i]) goto fail_data_pages; } - data->data_order = 0; data->nr_pages = nr_pages; return data; @@ -2382,6 +2389,11 @@ static void perf_mmap_data_free(struct perf_mmap_data *data) kfree(data); } +static inline int page_order(struct perf_mmap_data *data) +{ + return 0; +} + #else /* @@ -2390,10 +2402,15 @@ static void perf_mmap_data_free(struct perf_mmap_data *data) * Required for architectures that have d-cache aliasing issues. */ +static inline int page_order(struct perf_mmap_data *data) +{ + return data->page_order; +} + static struct page * perf_mmap_to_page(struct perf_mmap_data *data, unsigned long pgoff) { - if (pgoff > (1UL << data->data_order)) + if (pgoff > (1UL << page_order(data))) return NULL; return vmalloc_to_page((void *)data->user_page + pgoff * PAGE_SIZE); @@ -2413,7 +2430,7 @@ static void perf_mmap_data_free_work(struct work_struct *work) int i, nr; data = container_of(work, struct perf_mmap_data, work); - nr = 1 << data->data_order; + nr = 1 << page_order(data); base = data->user_page; for (i = 0; i < nr + 1; i++) @@ -2452,7 +2469,7 @@ perf_mmap_data_alloc(struct perf_event *event, int nr_pages) data->user_page = all_buf; data->data_pages[0] = all_buf + PAGE_SIZE; - data->data_order = ilog2(nr_pages); + data->page_order = ilog2(nr_pages); data->nr_pages = 1; return data; @@ -2466,6 +2483,11 @@ fail: #endif +static unsigned long perf_data_size(struct perf_mmap_data *data) +{ + return data->nr_pages << (PAGE_SHIFT + page_order(data)); +} + static int perf_mmap_fault(struct vm_area_struct *vma, struct vm_fault *vmf) { struct perf_event *event = vma->vm_file->private_data; @@ -2506,8 +2528,6 @@ perf_mmap_data_init(struct perf_event *event, struct perf_mmap_data *data) { long max_size = perf_data_size(data); - atomic_set(&data->lock, -1); - if (event->attr.watermark) { data->watermark = min_t(long, max_size, event->attr.wakeup_watermark); @@ -2580,6 +2600,14 @@ static int perf_mmap(struct file *file, struct vm_area_struct *vma) long user_extra, extra; int ret = 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; @@ -2885,120 +2913,80 @@ static void perf_output_wakeup(struct perf_output_handle *handle) } /* - * Curious locking construct. - * * We need to ensure a later event_id doesn't publish a head when a former - * event_id isn't done writing. However since we need to deal with NMIs we + * event isn't done writing. However since we need to deal with NMIs we * cannot fully serialize things. * - * What we do is serialize between CPUs so we only have to deal with NMI - * nesting on a single CPU. - * * We only publish the head (and generate a wakeup) when the outer-most - * event_id completes. + * event completes. */ -static void perf_output_lock(struct perf_output_handle *handle) +static void perf_output_get_handle(struct perf_output_handle *handle) { struct perf_mmap_data *data = handle->data; - int cur, cpu = get_cpu(); - - handle->locked = 0; - - for (;;) { - cur = atomic_cmpxchg(&data->lock, -1, cpu); - if (cur == -1) { - handle->locked = 1; - break; - } - if (cur == cpu) - break; - cpu_relax(); - } + preempt_disable(); + local_inc(&data->nest); + handle->wakeup = local_read(&data->wakeup); } -static void perf_output_unlock(struct perf_output_handle *handle) +static void perf_output_put_handle(struct perf_output_handle *handle) { struct perf_mmap_data *data = handle->data; unsigned long head; - int cpu; - - data->done_head = data->head; - - if (!handle->locked) - goto out; again: - /* - * The xchg implies a full barrier that ensures all writes are done - * before we publish the new head, matched by a rmb() in userspace when - * reading this position. - */ - while ((head = atomic_long_xchg(&data->done_head, 0))) - data->user_page->data_head = head; + head = local_read(&data->head); /* - * NMI can happen here, which means we can miss a done_head update. + * IRQ/NMI can happen here, which means we can miss a head update. */ - cpu = atomic_xchg(&data->lock, -1); - WARN_ON_ONCE(cpu != smp_processor_id()); + if (!local_dec_and_test(&data->nest)) + goto out; /* - * Therefore we have to validate we did not indeed do so. + * Publish the known good head. Rely on the full barrier implied + * by atomic_dec_and_test() order the data->head read and this + * write. */ - if (unlikely(atomic_long_read(&data->done_head))) { - /* - * Since we had it locked, we can lock it again. - */ - while (atomic_cmpxchg(&data->lock, -1, cpu) != -1) - cpu_relax(); + data->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 data->head. + */ + if (unlikely(head != local_read(&data->head))) { + local_inc(&data->nest); goto again; } - if (atomic_xchg(&data->wakeup, 0)) + if (handle->wakeup != local_read(&data->wakeup)) perf_output_wakeup(handle); -out: - put_cpu(); + + out: + preempt_enable(); } -void perf_output_copy(struct perf_output_handle *handle, +__always_inline void perf_output_copy(struct perf_output_handle *handle, const void *buf, unsigned int len) { - unsigned int pages_mask; - unsigned long offset; - unsigned int size; - void **pages; - - offset = handle->offset; - pages_mask = handle->data->nr_pages - 1; - pages = handle->data->data_pages; - do { - unsigned long page_offset; - unsigned long page_size; - int nr; + unsigned long size = min_t(unsigned long, handle->size, len); - nr = (offset >> PAGE_SHIFT) & pages_mask; - page_size = 1UL << (handle->data->data_order + PAGE_SHIFT); - page_offset = offset & (page_size - 1); - size = min_t(unsigned int, page_size - page_offset, len); + memcpy(handle->addr, buf, size); - memcpy(pages[nr] + page_offset, buf, size); + len -= size; + handle->addr += size; + handle->size -= size; + if (!handle->size) { + struct perf_mmap_data *data = handle->data; - len -= size; - buf += size; - offset += size; + handle->page++; + handle->page &= data->nr_pages - 1; + handle->addr = data->data_pages[handle->page]; + handle->size = PAGE_SIZE << page_order(data); + } } while (len); - - handle->offset = offset; - - /* - * Check we didn't copy past our reservation window, taking the - * possible unsigned int wrap into account. - */ - WARN_ON_ONCE(((long)(handle->head - handle->offset)) < 0); } int perf_output_begin(struct perf_output_handle *handle, @@ -3036,13 +3024,13 @@ int perf_output_begin(struct perf_output_handle *handle, handle->sample = sample; if (!data->nr_pages) - goto fail; + goto out; - have_lost = atomic_read(&data->lost); + have_lost = local_read(&data->lost); if (have_lost) size += sizeof(lost_event); - perf_output_lock(handle); + perf_output_get_handle(handle); do { /* @@ -3052,24 +3040,28 @@ int perf_output_begin(struct perf_output_handle *handle, */ tail = ACCESS_ONCE(data->user_page->data_tail); smp_rmb(); - offset = head = atomic_long_read(&data->head); + offset = head = local_read(&data->head); head += size; if (unlikely(!perf_output_space(data, tail, offset, head))) goto fail; - } while (atomic_long_cmpxchg(&data->head, offset, head) != offset); + } while (local_cmpxchg(&data->head, offset, head) != offset); - handle->offset = offset; - handle->head = head; + if (head - local_read(&data->wakeup) > data->watermark) + local_add(data->watermark, &data->wakeup); - if (head - tail > data->watermark) - atomic_set(&data->wakeup, 1); + handle->page = offset >> (PAGE_SHIFT + page_order(data)); + handle->page &= data->nr_pages - 1; + handle->size = offset & ((PAGE_SIZE << page_order(data)) - 1); + handle->addr = data->data_pages[handle->page]; + handle->addr += handle->size; + handle->size = (PAGE_SIZE << page_order(data)) - handle->size; if (have_lost) { lost_event.header.type = PERF_RECORD_LOST; lost_event.header.misc = 0; lost_event.header.size = sizeof(lost_event); lost_event.id = event->id; - lost_event.lost = atomic_xchg(&data->lost, 0); + lost_event.lost = local_xchg(&data->lost, 0); perf_output_put(handle, lost_event); } @@ -3077,8 +3069,8 @@ int perf_output_begin(struct perf_output_handle *handle, return 0; fail: - atomic_inc(&data->lost); - perf_output_unlock(handle); + local_inc(&data->lost); + perf_output_put_handle(handle); out: rcu_read_unlock(); @@ -3093,14 +3085,14 @@ void perf_output_end(struct perf_output_handle *handle) int wakeup_events = event->attr.wakeup_events; if (handle->sample && wakeup_events) { - int events = atomic_inc_return(&data->events); + int events = local_inc_return(&data->events); if (events >= wakeup_events) { - atomic_sub(wakeup_events, &data->events); - atomic_set(&data->wakeup, 1); + local_sub(wakeup_events, &data->events); + local_inc(&data->wakeup); } } - perf_output_unlock(handle); + perf_output_put_handle(handle); rcu_read_unlock(); } @@ -3436,22 +3428,13 @@ static void perf_event_task_output(struct perf_event *event, { struct perf_output_handle handle; struct task_struct *task = task_event->task; - unsigned long flags; int size, ret; - /* - * If this CPU attempts to acquire an rq lock held by a CPU spinning - * in perf_output_lock() from interrupt context, it's game over. - */ - local_irq_save(flags); - size = task_event->event_id.header.size; ret = perf_output_begin(&handle, event, size, 0, 0); - if (ret) { - local_irq_restore(flags); + if (ret) return; - } task_event->event_id.pid = perf_event_pid(event, task); task_event->event_id.ppid = perf_event_pid(event, current); @@ -3462,7 +3445,6 @@ static void perf_event_task_output(struct perf_event *event, perf_output_put(&handle, task_event->event_id); perf_output_end(&handle); - local_irq_restore(flags); } static int perf_event_task_match(struct perf_event *event) @@ -4020,9 +4002,6 @@ static void perf_swevent_add(struct perf_event *event, u64 nr, perf_swevent_overflow(event, 0, nmi, data, regs); } -static int perf_tp_event_match(struct perf_event *event, - struct perf_sample_data *data); - static int perf_exclude_event(struct perf_event *event, struct pt_regs *regs) { @@ -4052,10 +4031,6 @@ static int perf_swevent_match(struct perf_event *event, if (perf_exclude_event(event, regs)) return 0; - if (event->attr.type == PERF_TYPE_TRACEPOINT && - !perf_tp_event_match(event, data)) - return 0; - return 1; } @@ -4066,19 +4041,46 @@ static inline u64 swevent_hash(u64 type, u32 event_id) return hash_64(val, SWEVENT_HLIST_BITS); } -static struct hlist_head * -find_swevent_head(struct perf_cpu_context *ctx, u64 type, u32 event_id) +static inline struct hlist_head * +__find_swevent_head(struct swevent_hlist *hlist, u64 type, u32 event_id) { - u64 hash; - struct swevent_hlist *hlist; + u64 hash = swevent_hash(type, event_id); + + return &hlist->heads[hash]; +} - hash = swevent_hash(type, event_id); +/* For the read side: events when they trigger */ +static inline struct hlist_head * +find_swevent_head_rcu(struct perf_cpu_context *ctx, u64 type, u32 event_id) +{ + struct swevent_hlist *hlist; hlist = rcu_dereference(ctx->swevent_hlist); if (!hlist) return NULL; - return &hlist->heads[hash]; + 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 perf_cpu_context *ctx, 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(ctx->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, @@ -4095,7 +4097,7 @@ static void do_perf_sw_event(enum perf_type_id type, u32 event_id, rcu_read_lock(); - head = find_swevent_head(cpuctx, type, event_id); + head = find_swevent_head_rcu(cpuctx, type, event_id); if (!head) goto end; @@ -4110,7 +4112,7 @@ end: int perf_swevent_get_recursion_context(void) { - struct perf_cpu_context *cpuctx = &get_cpu_var(perf_cpu_context); + struct perf_cpu_context *cpuctx = &__get_cpu_var(perf_cpu_context); int rctx; if (in_nmi()) @@ -4122,10 +4124,8 @@ int perf_swevent_get_recursion_context(void) else rctx = 0; - if (cpuctx->recursion[rctx]) { - put_cpu_var(perf_cpu_context); + if (cpuctx->recursion[rctx]) return -1; - } cpuctx->recursion[rctx]++; barrier(); @@ -4139,7 +4139,6 @@ void perf_swevent_put_recursion_context(int rctx) struct perf_cpu_context *cpuctx = &__get_cpu_var(perf_cpu_context); barrier(); cpuctx->recursion[rctx]--; - put_cpu_var(perf_cpu_context); } EXPORT_SYMBOL_GPL(perf_swevent_put_recursion_context); @@ -4150,6 +4149,7 @@ void __perf_sw_event(u32 event_id, u64 nr, int nmi, struct perf_sample_data data; int rctx; + preempt_disable_notrace(); rctx = perf_swevent_get_recursion_context(); if (rctx < 0) return; @@ -4159,6 +4159,7 @@ void __perf_sw_event(u32 event_id, u64 nr, int nmi, 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) @@ -4178,7 +4179,7 @@ static int perf_swevent_enable(struct perf_event *event) perf_swevent_set_period(event); } - head = find_swevent_head(cpuctx, event->attr.type, event->attr.config); + head = find_swevent_head(cpuctx, event); if (WARN_ON_ONCE(!head)) return -EINVAL; @@ -4366,6 +4367,14 @@ static const struct pmu perf_ops_task_clock = { .read = task_clock_perf_event_read, }; +/* Deref the hlist from the update side */ +static inline struct swevent_hlist * +swevent_hlist_deref(struct perf_cpu_context *cpuctx) +{ + return rcu_dereference_protected(cpuctx->swevent_hlist, + lockdep_is_held(&cpuctx->hlist_mutex)); +} + static void swevent_hlist_release_rcu(struct rcu_head *rcu_head) { struct swevent_hlist *hlist; @@ -4376,12 +4385,11 @@ static void swevent_hlist_release_rcu(struct rcu_head *rcu_head) static void swevent_hlist_release(struct perf_cpu_context *cpuctx) { - struct swevent_hlist *hlist; + struct swevent_hlist *hlist = swevent_hlist_deref(cpuctx); - if (!cpuctx->swevent_hlist) + if (!hlist) return; - hlist = cpuctx->swevent_hlist; rcu_assign_pointer(cpuctx->swevent_hlist, NULL); call_rcu(&hlist->rcu_head, swevent_hlist_release_rcu); } @@ -4418,7 +4426,7 @@ static int swevent_hlist_get_cpu(struct perf_event *event, int cpu) mutex_lock(&cpuctx->hlist_mutex); - if (!cpuctx->swevent_hlist && cpu_online(cpu)) { + if (!swevent_hlist_deref(cpuctx) && cpu_online(cpu)) { struct swevent_hlist *hlist; hlist = kzalloc(sizeof(*hlist), GFP_KERNEL); @@ -4467,10 +4475,46 @@ static int swevent_hlist_get(struct perf_event *event) #ifdef CONFIG_EVENT_TRACING -void perf_tp_event(int event_id, u64 addr, u64 count, void *record, - int entry_size, struct pt_regs *regs) +static const struct pmu perf_ops_tracepoint = { + .enable = perf_trace_enable, + .disable = perf_trace_disable, + .read = perf_swevent_read, + .unthrottle = perf_swevent_unthrottle, +}; + +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) +{ + /* + * 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) { struct perf_sample_data data; + struct perf_event *event; + struct hlist_node *node; + struct perf_raw_record raw = { .size = entry_size, .data = record, @@ -4479,26 +4523,18 @@ void perf_tp_event(int event_id, u64 addr, u64 count, void *record, perf_sample_data_init(&data, addr); data.raw = &raw; - /* Trace events already protected against recursion */ - do_perf_sw_event(PERF_TYPE_TRACEPOINT, event_id, count, 1, - &data, regs); + rcu_read_lock(); + hlist_for_each_entry_rcu(event, node, head, hlist_entry) { + if (perf_tp_event_match(event, &data, regs)) + perf_swevent_add(event, count, 1, &data, regs); + } + rcu_read_unlock(); } EXPORT_SYMBOL_GPL(perf_tp_event); -static int perf_tp_event_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 void tp_perf_event_destroy(struct perf_event *event) { - perf_trace_disable(event->attr.config); - swevent_hlist_put(event); + perf_trace_destroy(event); } static const struct pmu *tp_perf_event_init(struct perf_event *event) @@ -4514,17 +4550,13 @@ static const struct pmu *tp_perf_event_init(struct perf_event *event) !capable(CAP_SYS_ADMIN)) return ERR_PTR(-EPERM); - if (perf_trace_enable(event->attr.config)) + err = perf_trace_init(event); + if (err) return NULL; event->destroy = tp_perf_event_destroy; - err = swevent_hlist_get(event); - if (err) { - perf_trace_disable(event->attr.config); - return ERR_PTR(err); - } - return &perf_ops_generic; + return &perf_ops_tracepoint; } static int perf_event_set_filter(struct perf_event *event, void __user *arg) @@ -4552,12 +4584,6 @@ static void perf_event_free_filter(struct perf_event *event) #else -static int perf_tp_event_match(struct perf_event *event, - struct perf_sample_data *data) -{ - return 1; -} - static const struct pmu *tp_perf_event_init(struct perf_event *event) { return NULL; @@ -4894,6 +4920,13 @@ static int perf_event_set_output(struct perf_event *event, int output_fd) int fput_needed = 0; int ret = -EINVAL; + /* + * Don't allow output of inherited per-task events. This would + * create performance issues due to cross cpu access. + */ + if (event->cpu == -1 && event->attr.inherit) + return -EINVAL; + if (!output_fd) goto set; @@ -4914,6 +4947,18 @@ static int perf_event_set_output(struct perf_event *event, int output_fd) if (event->data) 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; + atomic_long_inc(&output_file->f_count); set: diff --git a/kernel/profile.c b/kernel/profile.c index a55d3a3..dfadc5b 100644 --- a/kernel/profile.c +++ b/kernel/profile.c @@ -127,8 +127,10 @@ int __ref profile_init(void) return 0; prof_buffer = vmalloc(buffer_bytes); - if (prof_buffer) + if (prof_buffer) { + memset(prof_buffer, 0, buffer_bytes); return 0; + } free_cpumask_var(prof_cpu_mask); return -ENOMEM; diff --git a/kernel/ptrace.c b/kernel/ptrace.c index 9fb5123..6af9cdd 100644 --- a/kernel/ptrace.c +++ b/kernel/ptrace.c @@ -14,7 +14,6 @@ #include <linux/mm.h> #include <linux/highmem.h> #include <linux/pagemap.h> -#include <linux/smp_lock.h> #include <linux/ptrace.h> #include <linux/security.h> #include <linux/signal.h> @@ -665,10 +664,6 @@ SYSCALL_DEFINE4(ptrace, long, request, long, pid, long, addr, long, data) struct task_struct *child; long ret; - /* - * This lock_kernel fixes a subtle race with suid exec - */ - lock_kernel(); if (request == PTRACE_TRACEME) { ret = ptrace_traceme(); if (!ret) @@ -702,7 +697,6 @@ SYSCALL_DEFINE4(ptrace, long, request, long, pid, long, addr, long, data) out_put_task_struct: put_task_struct(child); out: - unlock_kernel(); return ret; } @@ -812,10 +806,6 @@ asmlinkage long compat_sys_ptrace(compat_long_t request, compat_long_t pid, struct task_struct *child; long ret; - /* - * This lock_kernel fixes a subtle race with suid exec - */ - lock_kernel(); if (request == PTRACE_TRACEME) { ret = ptrace_traceme(); goto out; @@ -845,7 +835,6 @@ asmlinkage long compat_sys_ptrace(compat_long_t request, compat_long_t pid, out_put_task_struct: put_task_struct(child); out: - unlock_kernel(); return ret; } #endif /* CONFIG_COMPAT */ diff --git a/kernel/rcupdate.c b/kernel/rcupdate.c index 03a7ea1..72a8dc9 100644 --- a/kernel/rcupdate.c +++ b/kernel/rcupdate.c @@ -44,7 +44,6 @@ #include <linux/cpu.h> #include <linux/mutex.h> #include <linux/module.h> -#include <linux/kernel_stat.h> #include <linux/hardirq.h> #ifdef CONFIG_DEBUG_LOCK_ALLOC @@ -64,9 +63,6 @@ struct lockdep_map rcu_sched_lock_map = EXPORT_SYMBOL_GPL(rcu_sched_lock_map); #endif -int rcu_scheduler_active __read_mostly; -EXPORT_SYMBOL_GPL(rcu_scheduler_active); - #ifdef CONFIG_DEBUG_LOCK_ALLOC int debug_lockdep_rcu_enabled(void) @@ -97,21 +93,6 @@ EXPORT_SYMBOL_GPL(rcu_read_lock_bh_held); #endif /* #ifdef CONFIG_DEBUG_LOCK_ALLOC */ /* - * This function is invoked towards the end of the scheduler's initialization - * process. Before this is called, the idle task might contain - * RCU read-side critical sections (during which time, this idle - * task is booting the system). After this function is called, the - * idle tasks are prohibited from containing RCU read-side critical - * sections. - */ -void rcu_scheduler_starting(void) -{ - WARN_ON(num_online_cpus() != 1); - WARN_ON(nr_context_switches() > 0); - rcu_scheduler_active = 1; -} - -/* * Awaken the corresponding synchronize_rcu() instance now that a * grace period has elapsed. */ @@ -122,3 +103,14 @@ void wakeme_after_rcu(struct rcu_head *head) rcu = container_of(head, struct rcu_synchronize, head); complete(&rcu->completion); } + +#ifdef CONFIG_PROVE_RCU +/* + * wrapper function to avoid #include problems. + */ +int rcu_my_thread_group_empty(void) +{ + return thread_group_empty(current); +} +EXPORT_SYMBOL_GPL(rcu_my_thread_group_empty); +#endif /* #ifdef CONFIG_PROVE_RCU */ diff --git a/kernel/rcutiny.c b/kernel/rcutiny.c index 9f6d9ff..38729d3 100644 --- a/kernel/rcutiny.c +++ b/kernel/rcutiny.c @@ -44,9 +44,9 @@ struct rcu_ctrlblk { }; /* Definition for rcupdate control block. */ -static struct rcu_ctrlblk rcu_ctrlblk = { - .donetail = &rcu_ctrlblk.rcucblist, - .curtail = &rcu_ctrlblk.rcucblist, +static struct rcu_ctrlblk rcu_sched_ctrlblk = { + .donetail = &rcu_sched_ctrlblk.rcucblist, + .curtail = &rcu_sched_ctrlblk.rcucblist, }; static struct rcu_ctrlblk rcu_bh_ctrlblk = { @@ -54,6 +54,11 @@ static struct rcu_ctrlblk rcu_bh_ctrlblk = { .curtail = &rcu_bh_ctrlblk.rcucblist, }; +#ifdef CONFIG_DEBUG_LOCK_ALLOC +int rcu_scheduler_active __read_mostly; +EXPORT_SYMBOL_GPL(rcu_scheduler_active); +#endif /* #ifdef CONFIG_DEBUG_LOCK_ALLOC */ + #ifdef CONFIG_NO_HZ static long rcu_dynticks_nesting = 1; @@ -108,7 +113,8 @@ static int rcu_qsctr_help(struct rcu_ctrlblk *rcp) */ void rcu_sched_qs(int cpu) { - if (rcu_qsctr_help(&rcu_ctrlblk) + rcu_qsctr_help(&rcu_bh_ctrlblk)) + if (rcu_qsctr_help(&rcu_sched_ctrlblk) + + rcu_qsctr_help(&rcu_bh_ctrlblk)) raise_softirq(RCU_SOFTIRQ); } @@ -173,7 +179,7 @@ static void __rcu_process_callbacks(struct rcu_ctrlblk *rcp) */ static void rcu_process_callbacks(struct softirq_action *unused) { - __rcu_process_callbacks(&rcu_ctrlblk); + __rcu_process_callbacks(&rcu_sched_ctrlblk); __rcu_process_callbacks(&rcu_bh_ctrlblk); } @@ -187,7 +193,8 @@ static void rcu_process_callbacks(struct softirq_action *unused) * * Cool, huh? (Due to Josh Triplett.) * - * But we want to make this a static inline later. + * But we want to make this a static inline later. The cond_resched() + * currently makes this problematic. */ void synchronize_sched(void) { @@ -195,12 +202,6 @@ void synchronize_sched(void) } EXPORT_SYMBOL_GPL(synchronize_sched); -void synchronize_rcu_bh(void) -{ - synchronize_sched(); -} -EXPORT_SYMBOL_GPL(synchronize_rcu_bh); - /* * Helper function for call_rcu() and call_rcu_bh(). */ @@ -226,7 +227,7 @@ static void __call_rcu(struct rcu_head *head, */ void call_rcu(struct rcu_head *head, void (*func)(struct rcu_head *rcu)) { - __call_rcu(head, func, &rcu_ctrlblk); + __call_rcu(head, func, &rcu_sched_ctrlblk); } EXPORT_SYMBOL_GPL(call_rcu); @@ -244,11 +245,13 @@ void rcu_barrier(void) { struct rcu_synchronize rcu; + init_rcu_head_on_stack(&rcu.head); init_completion(&rcu.completion); /* Will wake me after RCU finished. */ call_rcu(&rcu.head, wakeme_after_rcu); /* Wait for it. */ wait_for_completion(&rcu.completion); + destroy_rcu_head_on_stack(&rcu.head); } EXPORT_SYMBOL_GPL(rcu_barrier); @@ -256,11 +259,13 @@ void rcu_barrier_bh(void) { struct rcu_synchronize rcu; + init_rcu_head_on_stack(&rcu.head); init_completion(&rcu.completion); /* Will wake me after RCU finished. */ call_rcu_bh(&rcu.head, wakeme_after_rcu); /* Wait for it. */ wait_for_completion(&rcu.completion); + destroy_rcu_head_on_stack(&rcu.head); } EXPORT_SYMBOL_GPL(rcu_barrier_bh); @@ -268,11 +273,13 @@ void rcu_barrier_sched(void) { struct rcu_synchronize rcu; + init_rcu_head_on_stack(&rcu.head); init_completion(&rcu.completion); /* Will wake me after RCU finished. */ call_rcu_sched(&rcu.head, wakeme_after_rcu); /* Wait for it. */ wait_for_completion(&rcu.completion); + destroy_rcu_head_on_stack(&rcu.head); } EXPORT_SYMBOL_GPL(rcu_barrier_sched); @@ -280,3 +287,5 @@ void __init rcu_init(void) { open_softirq(RCU_SOFTIRQ, rcu_process_callbacks); } + +#include "rcutiny_plugin.h" diff --git a/kernel/rcutiny_plugin.h b/kernel/rcutiny_plugin.h new file mode 100644 index 0000000..d223a92bc --- /dev/null +++ b/kernel/rcutiny_plugin.h @@ -0,0 +1,39 @@ +/* + * Read-Copy Update mechanism for mutual exclusion (tree-based version) + * Internal non-public definitions that provide either classic + * or preemptable 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 + * 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 IBM Corporation, 2009 + * + * Author: Paul E. McKenney <paulmck@linux.vnet.ibm.com> + */ + +#ifdef CONFIG_DEBUG_LOCK_ALLOC + +#include <linux/kernel_stat.h> + +/* + * During boot, we forgive RCU lockdep issues. After this function is + * invoked, we start taking RCU lockdep issues seriously. + */ +void rcu_scheduler_starting(void) +{ + WARN_ON(nr_context_switches() > 0); + rcu_scheduler_active = 1; +} + +#endif /* #ifdef CONFIG_DEBUG_LOCK_ALLOC */ diff --git a/kernel/rcutorture.c b/kernel/rcutorture.c index 2b676f3..6535ac8 100644 --- a/kernel/rcutorture.c +++ b/kernel/rcutorture.c @@ -464,9 +464,11 @@ static void rcu_bh_torture_synchronize(void) { struct rcu_bh_torture_synchronize rcu; + init_rcu_head_on_stack(&rcu.head); init_completion(&rcu.completion); call_rcu_bh(&rcu.head, rcu_bh_torture_wakeme_after_cb); wait_for_completion(&rcu.completion); + destroy_rcu_head_on_stack(&rcu.head); } static struct rcu_torture_ops rcu_bh_ops = { diff --git a/kernel/rcutree.c b/kernel/rcutree.c index 3ec8160..d443734 100644 --- a/kernel/rcutree.c +++ b/kernel/rcutree.c @@ -46,6 +46,7 @@ #include <linux/cpu.h> #include <linux/mutex.h> #include <linux/time.h> +#include <linux/kernel_stat.h> #include "rcutree.h" @@ -53,8 +54,8 @@ static struct lock_class_key rcu_node_class[NUM_RCU_LVLS]; -#define RCU_STATE_INITIALIZER(name) { \ - .level = { &name.node[0] }, \ +#define RCU_STATE_INITIALIZER(structname) { \ + .level = { &structname.node[0] }, \ .levelcnt = { \ NUM_RCU_LVL_0, /* root of hierarchy. */ \ NUM_RCU_LVL_1, \ @@ -65,13 +66,14 @@ static struct lock_class_key rcu_node_class[NUM_RCU_LVLS]; .signaled = RCU_GP_IDLE, \ .gpnum = -300, \ .completed = -300, \ - .onofflock = __RAW_SPIN_LOCK_UNLOCKED(&name.onofflock), \ + .onofflock = __RAW_SPIN_LOCK_UNLOCKED(&structname.onofflock), \ .orphan_cbs_list = NULL, \ - .orphan_cbs_tail = &name.orphan_cbs_list, \ + .orphan_cbs_tail = &structname.orphan_cbs_list, \ .orphan_qlen = 0, \ - .fqslock = __RAW_SPIN_LOCK_UNLOCKED(&name.fqslock), \ + .fqslock = __RAW_SPIN_LOCK_UNLOCKED(&structname.fqslock), \ .n_force_qs = 0, \ .n_force_qs_ngp = 0, \ + .name = #structname, \ } struct rcu_state rcu_sched_state = RCU_STATE_INITIALIZER(rcu_sched_state); @@ -80,6 +82,9 @@ 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); +int rcu_scheduler_active __read_mostly; +EXPORT_SYMBOL_GPL(rcu_scheduler_active); + /* * 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 @@ -97,25 +102,32 @@ static int rcu_gp_in_progress(struct rcu_state *rsp) */ void rcu_sched_qs(int cpu) { - struct rcu_data *rdp; + struct rcu_data *rdp = &per_cpu(rcu_sched_data, cpu); - rdp = &per_cpu(rcu_sched_data, cpu); rdp->passed_quiesc_completed = rdp->gpnum - 1; barrier(); rdp->passed_quiesc = 1; - rcu_preempt_note_context_switch(cpu); } void rcu_bh_qs(int cpu) { - struct rcu_data *rdp; + struct rcu_data *rdp = &per_cpu(rcu_bh_data, cpu); - rdp = &per_cpu(rcu_bh_data, cpu); rdp->passed_quiesc_completed = rdp->gpnum - 1; barrier(); rdp->passed_quiesc = 1; } +/* + * Note a context switch. This is a quiescent state for RCU-sched, + * and requires special handling for preemptible RCU. + */ +void rcu_note_context_switch(int cpu) +{ + rcu_sched_qs(cpu); + rcu_preempt_note_context_switch(cpu); +} + #ifdef CONFIG_NO_HZ DEFINE_PER_CPU(struct rcu_dynticks, rcu_dynticks) = { .dynticks_nesting = 1, @@ -438,6 +450,8 @@ static int rcu_implicit_dynticks_qs(struct rcu_data *rdp) #ifdef CONFIG_RCU_CPU_STALL_DETECTOR +int rcu_cpu_stall_panicking __read_mostly; + static void record_gp_stall_check_time(struct rcu_state *rsp) { rsp->gp_start = jiffies; @@ -470,7 +484,8 @@ static void print_other_cpu_stall(struct rcu_state *rsp) /* OK, time to rat on our buddy... */ - printk(KERN_ERR "INFO: RCU detected CPU stalls:"); + printk(KERN_ERR "INFO: %s detected stalls on CPUs/tasks: {", + rsp->name); rcu_for_each_leaf_node(rsp, rnp) { raw_spin_lock_irqsave(&rnp->lock, flags); rcu_print_task_stall(rnp); @@ -481,7 +496,7 @@ static void print_other_cpu_stall(struct rcu_state *rsp) if (rnp->qsmask & (1UL << cpu)) printk(" %d", rnp->grplo + cpu); } - printk(" (detected by %d, t=%ld jiffies)\n", + printk("} (detected by %d, t=%ld jiffies)\n", smp_processor_id(), (long)(jiffies - rsp->gp_start)); trigger_all_cpu_backtrace(); @@ -497,8 +512,8 @@ static void print_cpu_stall(struct rcu_state *rsp) unsigned long flags; struct rcu_node *rnp = rcu_get_root(rsp); - printk(KERN_ERR "INFO: RCU detected CPU %d stall (t=%lu jiffies)\n", - smp_processor_id(), jiffies - rsp->gp_start); + printk(KERN_ERR "INFO: %s detected stall on CPU %d (t=%lu jiffies)\n", + rsp->name, smp_processor_id(), jiffies - rsp->gp_start); trigger_all_cpu_backtrace(); raw_spin_lock_irqsave(&rnp->lock, flags); @@ -515,6 +530,8 @@ static void check_cpu_stall(struct rcu_state *rsp, struct rcu_data *rdp) long delta; struct rcu_node *rnp; + if (rcu_cpu_stall_panicking) + return; delta = jiffies - rsp->jiffies_stall; rnp = rdp->mynode; if ((rnp->qsmask & rdp->grpmask) && delta >= 0) { @@ -529,6 +546,21 @@ static void check_cpu_stall(struct rcu_state *rsp, struct rcu_data *rdp) } } +static int rcu_panic(struct notifier_block *this, unsigned long ev, void *ptr) +{ + rcu_cpu_stall_panicking = 1; + return NOTIFY_DONE; +} + +static struct notifier_block rcu_panic_block = { + .notifier_call = rcu_panic, +}; + +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) @@ -539,6 +571,10 @@ static void check_cpu_stall(struct rcu_state *rsp, struct rcu_data *rdp) { } +static void __init check_cpu_stall_init(void) +{ +} + #endif /* #else #ifdef CONFIG_RCU_CPU_STALL_DETECTOR */ /* @@ -1125,8 +1161,6 @@ static void rcu_do_batch(struct rcu_state *rsp, struct rcu_data *rdp) */ void rcu_check_callbacks(int cpu, int user) { - if (!rcu_pending(cpu)) - return; /* if nothing for RCU to do. */ if (user || (idle_cpu(cpu) && rcu_scheduler_active && !in_softirq() && hardirq_count() <= (1 << HARDIRQ_SHIFT))) { @@ -1158,7 +1192,8 @@ void rcu_check_callbacks(int cpu, int user) rcu_bh_qs(cpu); } rcu_preempt_check_callbacks(cpu); - raise_softirq(RCU_SOFTIRQ); + if (rcu_pending(cpu)) + raise_softirq(RCU_SOFTIRQ); } #ifdef CONFIG_SMP @@ -1236,11 +1271,11 @@ static void force_quiescent_state(struct rcu_state *rsp, int relaxed) break; /* grace period idle or initializing, ignore. */ case RCU_SAVE_DYNTICK: - - raw_spin_unlock(&rnp->lock); /* irqs remain disabled */ if (RCU_SIGNAL_INIT != RCU_SAVE_DYNTICK) break; /* So gcc recognizes the dead code. */ + raw_spin_unlock(&rnp->lock); /* irqs remain disabled */ + /* Record dyntick-idle state. */ force_qs_rnp(rsp, dyntick_save_progress_counter); raw_spin_lock(&rnp->lock); /* irqs already disabled */ @@ -1449,11 +1484,13 @@ void synchronize_sched(void) if (rcu_blocking_is_gp()) return; + init_rcu_head_on_stack(&rcu.head); init_completion(&rcu.completion); /* Will wake me after RCU finished. */ call_rcu_sched(&rcu.head, wakeme_after_rcu); /* Wait for it. */ wait_for_completion(&rcu.completion); + destroy_rcu_head_on_stack(&rcu.head); } EXPORT_SYMBOL_GPL(synchronize_sched); @@ -1473,11 +1510,13 @@ void synchronize_rcu_bh(void) if (rcu_blocking_is_gp()) return; + init_rcu_head_on_stack(&rcu.head); init_completion(&rcu.completion); /* Will wake me after RCU finished. */ call_rcu_bh(&rcu.head, wakeme_after_rcu); /* Wait for it. */ wait_for_completion(&rcu.completion); + destroy_rcu_head_on_stack(&rcu.head); } EXPORT_SYMBOL_GPL(synchronize_rcu_bh); @@ -1498,8 +1537,20 @@ static int __rcu_pending(struct rcu_state *rsp, struct rcu_data *rdp) check_cpu_stall(rsp, rdp); /* Is the RCU core waiting for a quiescent state from this CPU? */ - if (rdp->qs_pending) { + if (rdp->qs_pending && !rdp->passed_quiesc) { + + /* + * If force_quiescent_state() coming soon and this CPU + * needs a quiescent state, and this is either RCU-sched + * or RCU-bh, force a local reschedule. + */ rdp->n_rp_qs_pending++; + if (!rdp->preemptable && + ULONG_CMP_LT(ACCESS_ONCE(rsp->jiffies_force_qs) - 1, + jiffies)) + set_need_resched(); + } else if (rdp->qs_pending && rdp->passed_quiesc) { + rdp->n_rp_report_qs++; return 1; } @@ -1767,6 +1818,21 @@ static int __cpuinit rcu_cpu_notify(struct notifier_block *self, } /* + * This function is invoked towards the end of the scheduler's initialization + * process. Before this is called, the idle task might contain + * RCU read-side critical sections (during which time, this idle + * task is booting the system). After this function is called, the + * idle tasks are prohibited from containing RCU read-side critical + * sections. This function also enables RCU lockdep checking. + */ +void rcu_scheduler_starting(void) +{ + WARN_ON(num_online_cpus() != 1); + WARN_ON(nr_context_switches() > 0); + rcu_scheduler_active = 1; +} + +/* * Compute the per-level fanout, either using the exact fanout specified * or balancing the tree, depending on CONFIG_RCU_FANOUT_EXACT. */ @@ -1849,6 +1915,14 @@ static void __init rcu_init_one(struct rcu_state *rsp) INIT_LIST_HEAD(&rnp->blocked_tasks[3]); } } + + rnp = rsp->level[NUM_RCU_LVLS - 1]; + for_each_possible_cpu(i) { + while (i > rnp->grphi) + rnp++; + rsp->rda[i]->mynode = rnp; + rcu_boot_init_percpu_data(i, rsp); + } } /* @@ -1859,19 +1933,11 @@ static void __init rcu_init_one(struct rcu_state *rsp) #define RCU_INIT_FLAVOR(rsp, rcu_data) \ do { \ int i; \ - int j; \ - struct rcu_node *rnp; \ \ - rcu_init_one(rsp); \ - rnp = (rsp)->level[NUM_RCU_LVLS - 1]; \ - j = 0; \ for_each_possible_cpu(i) { \ - if (i > rnp[j].grphi) \ - j++; \ - per_cpu(rcu_data, i).mynode = &rnp[j]; \ (rsp)->rda[i] = &per_cpu(rcu_data, i); \ - rcu_boot_init_percpu_data(i, rsp); \ } \ + rcu_init_one(rsp); \ } while (0) void __init rcu_init(void) @@ -1879,12 +1945,6 @@ void __init rcu_init(void) int cpu; rcu_bootup_announce(); -#ifdef CONFIG_RCU_CPU_STALL_DETECTOR - printk(KERN_INFO "RCU-based detection of stalled CPUs is enabled.\n"); -#endif /* #ifdef CONFIG_RCU_CPU_STALL_DETECTOR */ -#if NUM_RCU_LVL_4 != 0 - printk(KERN_INFO "Experimental four-level hierarchy is enabled.\n"); -#endif /* #if NUM_RCU_LVL_4 != 0 */ RCU_INIT_FLAVOR(&rcu_sched_state, rcu_sched_data); RCU_INIT_FLAVOR(&rcu_bh_state, rcu_bh_data); __rcu_init_preempt(); @@ -1898,6 +1958,7 @@ void __init rcu_init(void) cpu_notifier(rcu_cpu_notify, 0); for_each_online_cpu(cpu) rcu_cpu_notify(NULL, CPU_UP_PREPARE, (void *)(long)cpu); + check_cpu_stall_init(); } #include "rcutree_plugin.h" diff --git a/kernel/rcutree.h b/kernel/rcutree.h index 4a525a3..14c040b 100644 --- a/kernel/rcutree.h +++ b/kernel/rcutree.h @@ -223,6 +223,7 @@ struct rcu_data { /* 5) __rcu_pending() statistics. */ unsigned long n_rcu_pending; /* rcu_pending() calls since boot. */ unsigned long n_rp_qs_pending; + unsigned long n_rp_report_qs; unsigned long n_rp_cb_ready; unsigned long n_rp_cpu_needs_gp; unsigned long n_rp_gp_completed; @@ -326,6 +327,7 @@ struct rcu_state { unsigned long jiffies_stall; /* Time at which to check */ /* for CPU stalls. */ #endif /* #ifdef CONFIG_RCU_CPU_STALL_DETECTOR */ + char *name; /* Name of structure. */ }; /* Return values for rcu_preempt_offline_tasks(). */ diff --git a/kernel/rcutree_plugin.h b/kernel/rcutree_plugin.h index 79b53bd..0e4f420 100644 --- a/kernel/rcutree_plugin.h +++ b/kernel/rcutree_plugin.h @@ -26,6 +26,45 @@ #include <linux/delay.h> +/* + * Check the RCU kernel configuration parameters and print informative + * messages about anything out of the ordinary. If you like #ifdef, you + * will love this function. + */ +static void __init rcu_bootup_announce_oddness(void) +{ +#ifdef CONFIG_RCU_TRACE + printk(KERN_INFO "\tRCU debugfs-based tracing is enabled.\n"); +#endif +#if (defined(CONFIG_64BIT) && CONFIG_RCU_FANOUT != 64) || (!defined(CONFIG_64BIT) && CONFIG_RCU_FANOUT != 32) + printk(KERN_INFO "\tCONFIG_RCU_FANOUT set to non-default value of %d\n", + CONFIG_RCU_FANOUT); +#endif +#ifdef CONFIG_RCU_FANOUT_EXACT + printk(KERN_INFO "\tHierarchical RCU autobalancing is disabled.\n"); +#endif +#ifdef CONFIG_RCU_FAST_NO_HZ + printk(KERN_INFO + "\tRCU dyntick-idle grace-period acceleration is enabled.\n"); +#endif +#ifdef CONFIG_PROVE_RCU + printk(KERN_INFO "\tRCU lockdep checking is enabled.\n"); +#endif +#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 +#ifndef CONFIG_RCU_CPU_STALL_VERBOSE + printk(KERN_INFO "\tVerbose stalled-CPUs detection is disabled.\n"); +#endif +#if NUM_RCU_LVL_4 != 0 + printk(KERN_INFO "\tExperimental four-level hierarchy is enabled.\n"); +#endif +} + #ifdef CONFIG_TREE_PREEMPT_RCU struct rcu_state rcu_preempt_state = RCU_STATE_INITIALIZER(rcu_preempt_state); @@ -38,8 +77,8 @@ static int rcu_preempted_readers_exp(struct rcu_node *rnp); */ static void __init rcu_bootup_announce(void) { - printk(KERN_INFO - "Experimental preemptable hierarchical RCU implementation.\n"); + printk(KERN_INFO "Preemptable hierarchical RCU implementation.\n"); + rcu_bootup_announce_oddness(); } /* @@ -75,13 +114,19 @@ EXPORT_SYMBOL_GPL(rcu_force_quiescent_state); * 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. + * + * Unlike the other rcu_*_qs() functions, callers to this function + * must disable irqs in order to protect the assignment to + * ->rcu_read_unlock_special. */ static void rcu_preempt_qs(int cpu) { struct rcu_data *rdp = &per_cpu(rcu_preempt_data, cpu); + rdp->passed_quiesc_completed = rdp->gpnum - 1; barrier(); rdp->passed_quiesc = 1; + current->rcu_read_unlock_special &= ~RCU_READ_UNLOCK_NEED_QS; } /* @@ -144,9 +189,8 @@ static void rcu_preempt_note_context_switch(int cpu) * grace period, then the fact that the task has been enqueued * means that we continue to block the current grace period. */ - rcu_preempt_qs(cpu); local_irq_save(flags); - t->rcu_read_unlock_special &= ~RCU_READ_UNLOCK_NEED_QS; + rcu_preempt_qs(cpu); local_irq_restore(flags); } @@ -236,7 +280,6 @@ static void rcu_read_unlock_special(struct task_struct *t) */ special = t->rcu_read_unlock_special; if (special & RCU_READ_UNLOCK_NEED_QS) { - t->rcu_read_unlock_special &= ~RCU_READ_UNLOCK_NEED_QS; rcu_preempt_qs(smp_processor_id()); } @@ -473,7 +516,6 @@ static void rcu_preempt_check_callbacks(int cpu) struct task_struct *t = current; if (t->rcu_read_lock_nesting == 0) { - t->rcu_read_unlock_special &= ~RCU_READ_UNLOCK_NEED_QS; rcu_preempt_qs(cpu); return; } @@ -515,11 +557,13 @@ void synchronize_rcu(void) if (!rcu_scheduler_active) return; + init_rcu_head_on_stack(&rcu.head); init_completion(&rcu.completion); /* Will wake me after RCU finished. */ call_rcu(&rcu.head, wakeme_after_rcu); /* Wait for it. */ wait_for_completion(&rcu.completion); + destroy_rcu_head_on_stack(&rcu.head); } EXPORT_SYMBOL_GPL(synchronize_rcu); @@ -754,6 +798,7 @@ void exit_rcu(void) static void __init rcu_bootup_announce(void) { printk(KERN_INFO "Hierarchical RCU implementation.\n"); + rcu_bootup_announce_oddness(); } /* @@ -1008,6 +1053,8 @@ static DEFINE_PER_CPU(unsigned long, rcu_dyntick_holdoff); int rcu_needs_cpu(int cpu) { int c = 0; + int snap; + int snap_nmi; int thatcpu; /* Check for being in the holdoff period. */ @@ -1015,12 +1062,18 @@ int rcu_needs_cpu(int cpu) return rcu_needs_cpu_quick_check(cpu); /* Don't bother unless we are the last non-dyntick-idle CPU. */ - for_each_cpu_not(thatcpu, nohz_cpu_mask) - if (thatcpu != 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; + smp_mb(); /* Order sampling of snap with end of grace period. */ + 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); } + } /* Check and update the rcu_dyntick_drain sequencing. */ if (per_cpu(rcu_dyntick_drain, cpu) <= 0) { diff --git a/kernel/rcutree_trace.c b/kernel/rcutree_trace.c index d45db2e..36c95b4 100644 --- a/kernel/rcutree_trace.c +++ b/kernel/rcutree_trace.c @@ -241,11 +241,13 @@ static const struct file_operations rcugp_fops = { static void print_one_rcu_pending(struct seq_file *m, struct rcu_data *rdp) { seq_printf(m, "%3d%cnp=%ld " - "qsp=%ld cbr=%ld cng=%ld gpc=%ld gps=%ld nf=%ld nn=%ld\n", + "qsp=%ld rpq=%ld cbr=%ld cng=%ld " + "gpc=%ld gps=%ld nf=%ld nn=%ld\n", rdp->cpu, cpu_is_offline(rdp->cpu) ? '!' : ' ', rdp->n_rcu_pending, rdp->n_rp_qs_pending, + rdp->n_rp_report_qs, rdp->n_rp_cb_ready, rdp->n_rp_cpu_needs_gp, rdp->n_rp_gp_completed, diff --git a/kernel/sched.c b/kernel/sched.c index 78554dd..1d93cd0 100644 --- a/kernel/sched.c +++ b/kernel/sched.c @@ -3608,7 +3608,7 @@ need_resched: preempt_disable(); cpu = smp_processor_id(); rq = cpu_rq(cpu); - rcu_sched_qs(cpu); + rcu_note_context_switch(cpu); prev = rq->curr; switch_count = &prev->nivcsw; diff --git a/kernel/sched_debug.c b/kernel/sched_debug.c index 9cf1baf..87a330a 100644 --- a/kernel/sched_debug.c +++ b/kernel/sched_debug.c @@ -114,7 +114,9 @@ print_task(struct seq_file *m, struct rq *rq, struct task_struct *p) { char path[64]; + rcu_read_lock(); cgroup_path(task_group(p)->css.cgroup, path, sizeof(path)); + rcu_read_unlock(); SEQ_printf(m, " %s", path); } #endif diff --git a/kernel/softirq.c b/kernel/softirq.c index 7c1a67e..0db913a 100644 --- a/kernel/softirq.c +++ b/kernel/softirq.c @@ -716,7 +716,7 @@ static int run_ksoftirqd(void * __bind_cpu) preempt_enable_no_resched(); cond_resched(); preempt_disable(); - rcu_sched_qs((long)__bind_cpu); + rcu_note_context_switch((long)__bind_cpu); } preempt_enable(); set_current_state(TASK_INTERRUPTIBLE); diff --git a/kernel/stop_machine.c b/kernel/stop_machine.c index ef51d1f..b4e7431 100644 --- a/kernel/stop_machine.c +++ b/kernel/stop_machine.c @@ -294,7 +294,6 @@ static int __cpuinit cpu_stop_cpu_callback(struct notifier_block *nfb, struct sched_param param = { .sched_priority = MAX_RT_PRIO - 1 }; unsigned int cpu = (unsigned long)hcpu; struct cpu_stopper *stopper = &per_cpu(cpu_stopper, cpu); - struct cpu_stop_work *work; struct task_struct *p; switch (action & ~CPU_TASKS_FROZEN) { @@ -323,6 +322,9 @@ static int __cpuinit cpu_stop_cpu_callback(struct notifier_block *nfb, #ifdef CONFIG_HOTPLUG_CPU case CPU_UP_CANCELED: case CPU_DEAD: + { + struct cpu_stop_work *work; + /* kill the stopper */ kthread_stop(stopper->thread); /* drain remaining works */ @@ -335,6 +337,7 @@ static int __cpuinit cpu_stop_cpu_callback(struct notifier_block *nfb, put_task_struct(stopper->thread); stopper->thread = NULL; break; + } #endif } diff --git a/kernel/trace/trace_event_perf.c b/kernel/trace/trace_event_perf.c index 0a47e8d..26b8607 100644 --- a/kernel/trace/trace_event_perf.c +++ b/kernel/trace/trace_event_perf.c @@ -9,13 +9,9 @@ #include <linux/kprobes.h> #include "trace.h" -DEFINE_PER_CPU(struct pt_regs, perf_trace_regs); -EXPORT_PER_CPU_SYMBOL_GPL(perf_trace_regs); - EXPORT_SYMBOL_GPL(perf_arch_fetch_caller_regs); -static char *perf_trace_buf; -static char *perf_trace_buf_nmi; +static char *perf_trace_buf[4]; /* * Force it to be aligned to unsigned long to avoid misaligned accesses @@ -27,63 +23,82 @@ typedef typeof(unsigned long [PERF_MAX_TRACE_SIZE / sizeof(unsigned long)]) /* Count the events in use (per event id, not per instance) */ static int total_ref_count; -static int perf_trace_event_enable(struct ftrace_event_call *event) +static int perf_trace_event_init(struct ftrace_event_call *tp_event, + struct perf_event *p_event) { - char *buf; + struct hlist_head *list; int ret = -ENOMEM; + int cpu; - if (event->perf_refcount++ > 0) + p_event->tp_event = tp_event; + if (tp_event->perf_refcount++ > 0) return 0; - if (!total_ref_count) { - buf = (char *)alloc_percpu(perf_trace_t); - if (!buf) - goto fail_buf; + list = alloc_percpu(struct hlist_head); + if (!list) + goto fail; + + for_each_possible_cpu(cpu) + INIT_HLIST_HEAD(per_cpu_ptr(list, cpu)); - rcu_assign_pointer(perf_trace_buf, buf); + tp_event->perf_events = list; + + if (!total_ref_count) { + char *buf; + int i; - buf = (char *)alloc_percpu(perf_trace_t); - if (!buf) - goto fail_buf_nmi; + for (i = 0; i < 4; i++) { + buf = (char *)alloc_percpu(perf_trace_t); + if (!buf) + goto fail; - rcu_assign_pointer(perf_trace_buf_nmi, buf); + perf_trace_buf[i] = buf; + } } - if (event->class->reg) - ret = event->class->reg(event, TRACE_REG_PERF_REGISTER); + if (tp_event->class->reg) + ret = tp_event->class->reg(tp_event, TRACE_REG_PERF_REGISTER); else - ret = tracepoint_probe_register(event->name, - event->class->perf_probe, - event); - if (!ret) { - total_ref_count++; - return 0; - } + ret = tracepoint_probe_register(tp_event->name, + tp_event->class->perf_probe, + tp_event); + + if (ret) + goto fail; -fail_buf_nmi: + total_ref_count++; + return 0; + +fail: if (!total_ref_count) { - free_percpu(perf_trace_buf_nmi); - free_percpu(perf_trace_buf); - perf_trace_buf_nmi = NULL; - perf_trace_buf = NULL; + int i; + + for (i = 0; i < 4; i++) { + free_percpu(perf_trace_buf[i]); + perf_trace_buf[i] = NULL; + } + } + + if (!--tp_event->perf_refcount) { + free_percpu(tp_event->perf_events); + tp_event->perf_events = NULL; } -fail_buf: - event->perf_refcount--; return ret; } -int perf_trace_enable(int event_id) +int perf_trace_init(struct perf_event *p_event) { - struct ftrace_event_call *event; + struct ftrace_event_call *tp_event; + int event_id = p_event->attr.config; int ret = -EINVAL; mutex_lock(&event_mutex); - list_for_each_entry(event, &ftrace_events, list) { - if (event->event.type == event_id && - event->class && event->class->perf_probe && - try_module_get(event->mod)) { - ret = perf_trace_event_enable(event); + list_for_each_entry(tp_event, &ftrace_events, list) { + if (tp_event->event.type == event_id && + tp_event->class && tp_event->class->perf_probe && + try_module_get(tp_event->mod)) { + ret = perf_trace_event_init(tp_event, p_event); break; } } @@ -92,93 +107,76 @@ int perf_trace_enable(int event_id) return ret; } -static void perf_trace_event_disable(struct ftrace_event_call *event) +int perf_trace_enable(struct perf_event *p_event) { - char *buf, *nmi_buf; - - if (--event->perf_refcount > 0) - return; - - if (event->class->reg) - event->class->reg(event, TRACE_REG_PERF_UNREGISTER); - else - tracepoint_probe_unregister(event->name, event->class->perf_probe, event); + struct ftrace_event_call *tp_event = p_event->tp_event; + struct hlist_head *list; - if (!--total_ref_count) { - buf = perf_trace_buf; - rcu_assign_pointer(perf_trace_buf, NULL); + list = tp_event->perf_events; + if (WARN_ON_ONCE(!list)) + return -EINVAL; - nmi_buf = perf_trace_buf_nmi; - rcu_assign_pointer(perf_trace_buf_nmi, NULL); + list = per_cpu_ptr(list, smp_processor_id()); + hlist_add_head_rcu(&p_event->hlist_entry, list); - /* - * Ensure every events in profiling have finished before - * releasing the buffers - */ - synchronize_sched(); + return 0; +} - free_percpu(buf); - free_percpu(nmi_buf); - } +void perf_trace_disable(struct perf_event *p_event) +{ + hlist_del_rcu(&p_event->hlist_entry); } -void perf_trace_disable(int event_id) +void perf_trace_destroy(struct perf_event *p_event) { - struct ftrace_event_call *event; + struct ftrace_event_call *tp_event = p_event->tp_event; + int i; - mutex_lock(&event_mutex); - list_for_each_entry(event, &ftrace_events, list) { - if (event->event.type == event_id) { - perf_trace_event_disable(event); - module_put(event->mod); - break; + if (--tp_event->perf_refcount > 0) + return; + + if (tp_event->class->reg) + tp_event->class->reg(tp_event, TRACE_REG_PERF_UNREGISTER); + else + tracepoint_probe_unregister(tp_event->name, + tp_event->class->perf_probe, + tp_event); + + free_percpu(tp_event->perf_events); + tp_event->perf_events = NULL; + + if (!--total_ref_count) { + for (i = 0; i < 4; i++) { + free_percpu(perf_trace_buf[i]); + perf_trace_buf[i] = NULL; } } - mutex_unlock(&event_mutex); } __kprobes void *perf_trace_buf_prepare(int size, unsigned short type, - int *rctxp, unsigned long *irq_flags) + struct pt_regs *regs, int *rctxp) { struct trace_entry *entry; - char *trace_buf, *raw_data; - int pc, cpu; + char *raw_data; + int pc; BUILD_BUG_ON(PERF_MAX_TRACE_SIZE % sizeof(unsigned long)); pc = preempt_count(); - /* Protect the per cpu buffer, begin the rcu read side */ - local_irq_save(*irq_flags); - *rctxp = perf_swevent_get_recursion_context(); if (*rctxp < 0) - goto err_recursion; - - cpu = smp_processor_id(); - - if (in_nmi()) - trace_buf = rcu_dereference_sched(perf_trace_buf_nmi); - else - trace_buf = rcu_dereference_sched(perf_trace_buf); - - if (!trace_buf) - goto err; + return NULL; - raw_data = per_cpu_ptr(trace_buf, cpu); + raw_data = per_cpu_ptr(perf_trace_buf[*rctxp], smp_processor_id()); /* zero the dead bytes from align to not leak stack to user */ memset(&raw_data[size - sizeof(u64)], 0, sizeof(u64)); entry = (struct trace_entry *)raw_data; - tracing_generic_entry_update(entry, *irq_flags, pc); + tracing_generic_entry_update(entry, regs->flags, pc); entry->type = type; return raw_data; -err: - perf_swevent_put_recursion_context(*rctxp); -err_recursion: - local_irq_restore(*irq_flags); - return NULL; } EXPORT_SYMBOL_GPL(perf_trace_buf_prepare); diff --git a/kernel/trace/trace_kprobe.c b/kernel/trace/trace_kprobe.c index 9a082bb..faf7cef 100644 --- a/kernel/trace/trace_kprobe.c +++ b/kernel/trace/trace_kprobe.c @@ -1338,9 +1338,9 @@ static __kprobes void kprobe_perf_func(struct kprobe *kp, struct trace_probe *tp = container_of(kp, struct trace_probe, rp.kp); struct ftrace_event_call *call = &tp->call; struct kprobe_trace_entry_head *entry; + struct hlist_head *head; u8 *data; int size, __size, i; - unsigned long irq_flags; int rctx; __size = sizeof(*entry) + tp->size; @@ -1350,8 +1350,7 @@ static __kprobes void kprobe_perf_func(struct kprobe *kp, "profile buffer not large enough")) return; - entry = perf_trace_buf_prepare(size, call->event.type, - &rctx, &irq_flags); + entry = perf_trace_buf_prepare(size, call->event.type, regs, &rctx); if (!entry) return; @@ -1360,7 +1359,8 @@ static __kprobes void kprobe_perf_func(struct kprobe *kp, for (i = 0; i < tp->nr_args; i++) call_fetch(&tp->args[i].fetch, regs, data + tp->args[i].offset); - perf_trace_buf_submit(entry, size, rctx, entry->ip, 1, irq_flags, regs); + head = per_cpu_ptr(call->perf_events, smp_processor_id()); + perf_trace_buf_submit(entry, size, rctx, entry->ip, 1, regs, head); } /* Kretprobe profile handler */ @@ -1370,9 +1370,9 @@ static __kprobes void kretprobe_perf_func(struct kretprobe_instance *ri, struct trace_probe *tp = container_of(ri->rp, struct trace_probe, rp); struct ftrace_event_call *call = &tp->call; struct kretprobe_trace_entry_head *entry; + struct hlist_head *head; u8 *data; int size, __size, i; - unsigned long irq_flags; int rctx; __size = sizeof(*entry) + tp->size; @@ -1382,8 +1382,7 @@ static __kprobes void kretprobe_perf_func(struct kretprobe_instance *ri, "profile buffer not large enough")) return; - entry = perf_trace_buf_prepare(size, call->event.type, - &rctx, &irq_flags); + entry = perf_trace_buf_prepare(size, call->event.type, regs, &rctx); if (!entry) return; @@ -1393,8 +1392,8 @@ static __kprobes void kretprobe_perf_func(struct kretprobe_instance *ri, for (i = 0; i < tp->nr_args; i++) call_fetch(&tp->args[i].fetch, regs, data + tp->args[i].offset); - perf_trace_buf_submit(entry, size, rctx, entry->ret_ip, 1, - irq_flags, regs); + head = per_cpu_ptr(call->perf_events, smp_processor_id()); + perf_trace_buf_submit(entry, size, rctx, entry->ret_ip, 1, regs, head); } static int probe_perf_enable(struct ftrace_event_call *call) diff --git a/kernel/trace/trace_syscalls.c b/kernel/trace/trace_syscalls.c index 9d35830..d2c859c 100644 --- a/kernel/trace/trace_syscalls.c +++ b/kernel/trace/trace_syscalls.c @@ -488,7 +488,7 @@ static void perf_syscall_enter(void *ignore, struct pt_regs *regs, long id) { struct syscall_metadata *sys_data; struct syscall_trace_enter *rec; - unsigned long flags; + struct hlist_head *head; int syscall_nr; int rctx; int size; @@ -511,15 +511,16 @@ static void perf_syscall_enter(void *ignore, struct pt_regs *regs, long id) return; rec = (struct syscall_trace_enter *)perf_trace_buf_prepare(size, - sys_data->enter_event->event.type, - &rctx, &flags); + sys_data->enter_event->event.type, regs, &rctx); if (!rec) return; rec->nr = syscall_nr; syscall_get_arguments(current, regs, 0, sys_data->nb_args, (unsigned long *)&rec->args); - perf_trace_buf_submit(rec, size, rctx, 0, 1, flags, regs); + + head = per_cpu_ptr(sys_data->enter_event->perf_events, smp_processor_id()); + perf_trace_buf_submit(rec, size, rctx, 0, 1, regs, head); } int perf_sysenter_enable(struct ftrace_event_call *call) @@ -561,7 +562,7 @@ static void perf_syscall_exit(void *ignore, struct pt_regs *regs, long ret) { struct syscall_metadata *sys_data; struct syscall_trace_exit *rec; - unsigned long flags; + struct hlist_head *head; int syscall_nr; int rctx; int size; @@ -587,15 +588,15 @@ static void perf_syscall_exit(void *ignore, struct pt_regs *regs, long ret) return; rec = (struct syscall_trace_exit *)perf_trace_buf_prepare(size, - sys_data->exit_event->event.type, - &rctx, &flags); + sys_data->exit_event->event.type, regs, &rctx); if (!rec) return; rec->nr = syscall_nr; rec->ret = syscall_get_return_value(current, regs); - perf_trace_buf_submit(rec, size, rctx, 0, 1, flags, regs); + head = per_cpu_ptr(sys_data->exit_event->perf_events, smp_processor_id()); + perf_trace_buf_submit(rec, size, rctx, 0, 1, regs, head); } int perf_sysexit_enable(struct ftrace_event_call *call) |