Peter Zijlstra | ac199db | 2009-03-19 20:26:15 +0100 | [diff] [blame] | 1 | /* |
| 2 | * trace event based perf counter profiling |
| 3 | * |
| 4 | * Copyright (C) 2009 Red Hat Inc, Peter Zijlstra <pzijlstr@redhat.com> |
| 5 | * |
| 6 | */ |
| 7 | |
Li Zefan | 558e654 | 2009-08-24 12:19:47 +0800 | [diff] [blame] | 8 | #include <linux/module.h> |
Peter Zijlstra | ac199db | 2009-03-19 20:26:15 +0100 | [diff] [blame] | 9 | #include "trace.h" |
| 10 | |
Frederic Weisbecker | 20ab4425 | 2009-09-18 06:10:28 +0200 | [diff] [blame] | 11 | /* |
| 12 | * We can't use a size but a type in alloc_percpu() |
| 13 | * So let's create a dummy type that matches the desired size |
| 14 | */ |
| 15 | typedef struct {char buf[FTRACE_MAX_PROFILE_SIZE];} profile_buf_t; |
| 16 | |
| 17 | char *trace_profile_buf; |
Peter Zijlstra | 05bafda | 2009-09-20 12:34:38 +0200 | [diff] [blame] | 18 | EXPORT_SYMBOL_GPL(trace_profile_buf); |
| 19 | |
| 20 | char *trace_profile_buf_nmi; |
| 21 | EXPORT_SYMBOL_GPL(trace_profile_buf_nmi); |
Frederic Weisbecker | 20ab4425 | 2009-09-18 06:10:28 +0200 | [diff] [blame] | 22 | |
| 23 | /* Count the events in use (per event id, not per instance) */ |
| 24 | static int total_profile_count; |
| 25 | |
Frederic Weisbecker | e5e25cf | 2009-09-18 00:54:43 +0200 | [diff] [blame] | 26 | static int ftrace_profile_enable_event(struct ftrace_event_call *event) |
| 27 | { |
Frederic Weisbecker | 20ab4425 | 2009-09-18 06:10:28 +0200 | [diff] [blame] | 28 | char *buf; |
| 29 | int ret = -ENOMEM; |
| 30 | |
Frederic Weisbecker | e5e25cf | 2009-09-18 00:54:43 +0200 | [diff] [blame] | 31 | if (atomic_inc_return(&event->profile_count)) |
| 32 | return 0; |
| 33 | |
Frederic Weisbecker | fe8e5b5 | 2009-10-03 14:55:18 +0200 | [diff] [blame^] | 34 | if (!total_profile_count) { |
Frederic Weisbecker | 20ab4425 | 2009-09-18 06:10:28 +0200 | [diff] [blame] | 35 | buf = (char *)alloc_percpu(profile_buf_t); |
| 36 | if (!buf) |
| 37 | goto fail_buf; |
| 38 | |
| 39 | rcu_assign_pointer(trace_profile_buf, buf); |
| 40 | |
| 41 | buf = (char *)alloc_percpu(profile_buf_t); |
| 42 | if (!buf) |
| 43 | goto fail_buf_nmi; |
| 44 | |
| 45 | rcu_assign_pointer(trace_profile_buf_nmi, buf); |
| 46 | } |
| 47 | |
| 48 | ret = event->profile_enable(); |
Frederic Weisbecker | fe8e5b5 | 2009-10-03 14:55:18 +0200 | [diff] [blame^] | 49 | if (!ret) { |
| 50 | total_profile_count++; |
Frederic Weisbecker | 20ab4425 | 2009-09-18 06:10:28 +0200 | [diff] [blame] | 51 | return 0; |
Frederic Weisbecker | fe8e5b5 | 2009-10-03 14:55:18 +0200 | [diff] [blame^] | 52 | } |
Frederic Weisbecker | 20ab4425 | 2009-09-18 06:10:28 +0200 | [diff] [blame] | 53 | |
Frederic Weisbecker | 20ab4425 | 2009-09-18 06:10:28 +0200 | [diff] [blame] | 54 | fail_buf_nmi: |
Frederic Weisbecker | fe8e5b5 | 2009-10-03 14:55:18 +0200 | [diff] [blame^] | 55 | if (!total_profile_count) { |
| 56 | kfree(trace_profile_buf_nmi); |
| 57 | kfree(trace_profile_buf); |
| 58 | trace_profile_buf_nmi = NULL; |
| 59 | trace_profile_buf = NULL; |
| 60 | } |
Frederic Weisbecker | 20ab4425 | 2009-09-18 06:10:28 +0200 | [diff] [blame] | 61 | fail_buf: |
Frederic Weisbecker | 20ab4425 | 2009-09-18 06:10:28 +0200 | [diff] [blame] | 62 | atomic_dec(&event->profile_count); |
| 63 | |
| 64 | return ret; |
Frederic Weisbecker | e5e25cf | 2009-09-18 00:54:43 +0200 | [diff] [blame] | 65 | } |
| 66 | |
Peter Zijlstra | ac199db | 2009-03-19 20:26:15 +0100 | [diff] [blame] | 67 | int ftrace_profile_enable(int event_id) |
| 68 | { |
| 69 | struct ftrace_event_call *event; |
Li Zefan | 20c8928 | 2009-05-06 10:33:45 +0800 | [diff] [blame] | 70 | int ret = -EINVAL; |
Peter Zijlstra | ac199db | 2009-03-19 20:26:15 +0100 | [diff] [blame] | 71 | |
Li Zefan | 20c8928 | 2009-05-06 10:33:45 +0800 | [diff] [blame] | 72 | mutex_lock(&event_mutex); |
Steven Rostedt | a59fd60 | 2009-04-10 13:52:20 -0400 | [diff] [blame] | 73 | list_for_each_entry(event, &ftrace_events, list) { |
Li Zefan | 558e654 | 2009-08-24 12:19:47 +0800 | [diff] [blame] | 74 | if (event->id == event_id && event->profile_enable && |
| 75 | try_module_get(event->mod)) { |
Frederic Weisbecker | e5e25cf | 2009-09-18 00:54:43 +0200 | [diff] [blame] | 76 | ret = ftrace_profile_enable_event(event); |
Li Zefan | 20c8928 | 2009-05-06 10:33:45 +0800 | [diff] [blame] | 77 | break; |
| 78 | } |
Peter Zijlstra | ac199db | 2009-03-19 20:26:15 +0100 | [diff] [blame] | 79 | } |
Li Zefan | 20c8928 | 2009-05-06 10:33:45 +0800 | [diff] [blame] | 80 | mutex_unlock(&event_mutex); |
Peter Zijlstra | ac199db | 2009-03-19 20:26:15 +0100 | [diff] [blame] | 81 | |
Li Zefan | 20c8928 | 2009-05-06 10:33:45 +0800 | [diff] [blame] | 82 | return ret; |
Peter Zijlstra | ac199db | 2009-03-19 20:26:15 +0100 | [diff] [blame] | 83 | } |
| 84 | |
Frederic Weisbecker | e5e25cf | 2009-09-18 00:54:43 +0200 | [diff] [blame] | 85 | static void ftrace_profile_disable_event(struct ftrace_event_call *event) |
| 86 | { |
Frederic Weisbecker | 20ab4425 | 2009-09-18 06:10:28 +0200 | [diff] [blame] | 87 | char *buf, *nmi_buf; |
| 88 | |
Frederic Weisbecker | e5e25cf | 2009-09-18 00:54:43 +0200 | [diff] [blame] | 89 | if (!atomic_add_negative(-1, &event->profile_count)) |
| 90 | return; |
| 91 | |
| 92 | event->profile_disable(); |
Frederic Weisbecker | 20ab4425 | 2009-09-18 06:10:28 +0200 | [diff] [blame] | 93 | |
| 94 | if (!--total_profile_count) { |
| 95 | buf = trace_profile_buf; |
| 96 | rcu_assign_pointer(trace_profile_buf, NULL); |
| 97 | |
| 98 | nmi_buf = trace_profile_buf_nmi; |
| 99 | rcu_assign_pointer(trace_profile_buf_nmi, NULL); |
| 100 | |
| 101 | /* |
| 102 | * Ensure every events in profiling have finished before |
| 103 | * releasing the buffers |
| 104 | */ |
| 105 | synchronize_sched(); |
| 106 | |
| 107 | free_percpu(buf); |
| 108 | free_percpu(nmi_buf); |
| 109 | } |
Frederic Weisbecker | e5e25cf | 2009-09-18 00:54:43 +0200 | [diff] [blame] | 110 | } |
| 111 | |
Peter Zijlstra | ac199db | 2009-03-19 20:26:15 +0100 | [diff] [blame] | 112 | void ftrace_profile_disable(int event_id) |
| 113 | { |
| 114 | struct ftrace_event_call *event; |
| 115 | |
Li Zefan | 20c8928 | 2009-05-06 10:33:45 +0800 | [diff] [blame] | 116 | mutex_lock(&event_mutex); |
Steven Rostedt | a59fd60 | 2009-04-10 13:52:20 -0400 | [diff] [blame] | 117 | list_for_each_entry(event, &ftrace_events, list) { |
Li Zefan | 20c8928 | 2009-05-06 10:33:45 +0800 | [diff] [blame] | 118 | if (event->id == event_id) { |
Frederic Weisbecker | e5e25cf | 2009-09-18 00:54:43 +0200 | [diff] [blame] | 119 | ftrace_profile_disable_event(event); |
Li Zefan | 558e654 | 2009-08-24 12:19:47 +0800 | [diff] [blame] | 120 | module_put(event->mod); |
Li Zefan | 20c8928 | 2009-05-06 10:33:45 +0800 | [diff] [blame] | 121 | break; |
| 122 | } |
Peter Zijlstra | ac199db | 2009-03-19 20:26:15 +0100 | [diff] [blame] | 123 | } |
Li Zefan | 20c8928 | 2009-05-06 10:33:45 +0800 | [diff] [blame] | 124 | mutex_unlock(&event_mutex); |
Peter Zijlstra | ac199db | 2009-03-19 20:26:15 +0100 | [diff] [blame] | 125 | } |