From e5e25cf47b0bdd1f7e9b8bb6368ee48e16de0c87 Mon Sep 17 00:00:00 2001 From: Frederic Weisbecker Date: Fri, 18 Sep 2009 00:54:43 +0200 Subject: tracing: Factorize the events profile accounting Factorize the events enabling accounting in a common tracing core helper. This reduces the size of the profile_enable() and profile_disable() callbacks for each trace events. Signed-off-by: Frederic Weisbecker Acked-by: Steven Rostedt Acked-by: Li Zefan Cc: Peter Zijlstra Cc: Jason Baron Cc: Masami Hiramatsu Cc: Ingo Molnar --- include/trace/ftrace.h | 28 ++++++++-------------------- 1 file changed, 8 insertions(+), 20 deletions(-) (limited to 'include/trace') diff --git a/include/trace/ftrace.h b/include/trace/ftrace.h index 72a3b43..a822087 100644 --- a/include/trace/ftrace.h +++ b/include/trace/ftrace.h @@ -382,20 +382,14 @@ static inline int ftrace_get_offsets_##call( \ * * NOTE: The insertion profile callback (ftrace_profile_) is defined later * - * static int ftrace_profile_enable_(struct ftrace_event_call *event_call) + * static int ftrace_profile_enable_(void) * { - * int ret = 0; - * - * if (!atomic_inc_return(&event_call->profile_count)) - * ret = register_trace_(ftrace_profile_); - * - * return ret; + * return register_trace_(ftrace_profile_); * } * - * static void ftrace_profile_disable_(struct ftrace_event_call *event_call) + * static void ftrace_profile_disable_(void) * { - * if (atomic_add_negative(-1, &event->call->profile_count)) - * unregister_trace_(ftrace_profile_); + * unregister_trace_(ftrace_profile_); * } * */ @@ -405,20 +399,14 @@ static inline int ftrace_get_offsets_##call( \ \ static void ftrace_profile_##call(proto); \ \ -static int ftrace_profile_enable_##call(struct ftrace_event_call *event_call) \ +static int ftrace_profile_enable_##call(void) \ { \ - int ret = 0; \ - \ - if (!atomic_inc_return(&event_call->profile_count)) \ - ret = register_trace_##call(ftrace_profile_##call); \ - \ - return ret; \ + return register_trace_##call(ftrace_profile_##call); \ } \ \ -static void ftrace_profile_disable_##call(struct ftrace_event_call *event_call)\ +static void ftrace_profile_disable_##call(void) \ { \ - if (atomic_add_negative(-1, &event_call->profile_count)) \ - unregister_trace_##call(ftrace_profile_##call); \ + unregister_trace_##call(ftrace_profile_##call); \ } #include TRACE_INCLUDE(TRACE_INCLUDE_FILE) -- cgit v1.1 From 20ab4425a77a1f34028cc6ce57053c22c184ba5f Mon Sep 17 00:00:00 2001 From: Frederic Weisbecker Date: Fri, 18 Sep 2009 06:10:28 +0200 Subject: tracing: Allocate the ftrace event profile buffer dynamically Currently the trace event profile buffer is allocated in the stack. But this may be too much for the stack, as the events can have large statically defined field size and can also grow with dynamic arrays. Allocate two per cpu buffer for all profiled events. The first cpu buffer is used to host every non-nmi context traces. It is protected by disabling the interrupts while writing and committing the trace. The second buffer is reserved for nmi. So that there is no race between them and the first buffer. The whole write/commit section is rcu protected because we release these buffers while deactivating the last profiling trace event. v2: Move the buffers from trace_event to be global, as pointed by Steven Rostedt. v3: Fix the syscall events to handle the profiling buffer races by disabling interrupts, now that the buffers are globals. Suggested-by: Steven Rostedt Signed-off-by: Frederic Weisbecker Cc: Steven Rostedt Cc: Peter Zijlstra Cc: Li Zefan Cc: Jason Baron Cc: Masami Hiramatsu Cc: Ingo Molnar --- include/trace/ftrace.h | 83 +++++++++++++++++++++++++++++++++----------------- 1 file changed, 55 insertions(+), 28 deletions(-) (limited to 'include/trace') diff --git a/include/trace/ftrace.h b/include/trace/ftrace.h index a822087..a0361cb 100644 --- a/include/trace/ftrace.h +++ b/include/trace/ftrace.h @@ -648,11 +648,12 @@ __attribute__((section("_ftrace_events"))) event_##call = { \ * struct ftrace_raw_##call *entry; * u64 __addr = 0, __count = 1; * unsigned long irq_flags; + * struct trace_entry *ent; * int __entry_size; * int __data_size; + * int __cpu * int pc; * - * local_save_flags(irq_flags); * pc = preempt_count(); * * __data_size = ftrace_get_offsets_(&__data_offsets, args); @@ -663,25 +664,34 @@ __attribute__((section("_ftrace_events"))) event_##call = { \ * sizeof(u64)); * __entry_size -= sizeof(u32); * - * do { - * char raw_data[__entry_size]; <- allocate our sample in the stack - * struct trace_entry *ent; + * // Protect the non nmi buffer + * // This also protects the rcu read side + * local_irq_save(irq_flags); + * __cpu = smp_processor_id(); + * + * if (in_nmi()) + * raw_data = rcu_dereference(trace_profile_buf_nmi); + * else + * raw_data = rcu_dereference(trace_profile_buf); + * + * if (!raw_data) + * goto end; * - * zero dead bytes from alignment to avoid stack leak to userspace: + * raw_data = per_cpu_ptr(raw_data, __cpu); * - * *(u64 *)(&raw_data[__entry_size - sizeof(u64)]) = 0ULL; - * entry = (struct ftrace_raw_ *)raw_data; - * ent = &entry->ent; - * tracing_generic_entry_update(ent, irq_flags, pc); - * ent->type = event_call->id; + * //zero dead bytes from alignment to avoid stack leak to userspace: + * *(u64 *)(&raw_data[__entry_size - sizeof(u64)]) = 0ULL; + * entry = (struct ftrace_raw_ *)raw_data; + * ent = &entry->ent; + * tracing_generic_entry_update(ent, irq_flags, pc); + * ent->type = event_call->id; * - * <- do some jobs with dynamic arrays + * <- do some jobs with dynamic arrays * - * <- affect our values + * <- affect our values * - * perf_tpcounter_event(event_call->id, __addr, __count, entry, - * __entry_size); <- submit them to perf counter - * } while (0); + * perf_tpcounter_event(event_call->id, __addr, __count, entry, + * __entry_size); <- submit them to perf counter * * } */ @@ -704,11 +714,13 @@ static void ftrace_profile_##call(proto) \ struct ftrace_raw_##call *entry; \ u64 __addr = 0, __count = 1; \ unsigned long irq_flags; \ + struct trace_entry *ent; \ int __entry_size; \ int __data_size; \ + char *raw_data; \ + int __cpu; \ int pc; \ \ - local_save_flags(irq_flags); \ pc = preempt_count(); \ \ __data_size = ftrace_get_offsets_##call(&__data_offsets, args); \ @@ -716,23 +728,38 @@ static void ftrace_profile_##call(proto) \ sizeof(u64)); \ __entry_size -= sizeof(u32); \ \ - do { \ - char raw_data[__entry_size]; \ - struct trace_entry *ent; \ + if (WARN_ONCE(__entry_size > FTRACE_MAX_PROFILE_SIZE, \ + "profile buffer not large enough")) \ + return; \ + \ + local_irq_save(irq_flags); \ + __cpu = smp_processor_id(); \ \ - *(u64 *)(&raw_data[__entry_size - sizeof(u64)]) = 0ULL; \ - entry = (struct ftrace_raw_##call *)raw_data; \ - ent = &entry->ent; \ - tracing_generic_entry_update(ent, irq_flags, pc); \ - ent->type = event_call->id; \ + if (in_nmi()) \ + raw_data = rcu_dereference(trace_profile_buf_nmi); \ + else \ + raw_data = rcu_dereference(trace_profile_buf); \ \ - tstruct \ + if (!raw_data) \ + goto end; \ \ - { assign; } \ + raw_data = per_cpu_ptr(raw_data, __cpu); \ \ - perf_tpcounter_event(event_call->id, __addr, __count, entry,\ + *(u64 *)(&raw_data[__entry_size - sizeof(u64)]) = 0ULL; \ + entry = (struct ftrace_raw_##call *)raw_data; \ + ent = &entry->ent; \ + tracing_generic_entry_update(ent, irq_flags, pc); \ + ent->type = event_call->id; \ + \ + tstruct \ + \ + { assign; } \ + \ + perf_tpcounter_event(event_call->id, __addr, __count, entry, \ __entry_size); \ - } while (0); \ + \ +end: \ + local_irq_restore(irq_flags); \ \ } -- cgit v1.1