Commit | Line | Data |
---|---|---|
ac199db0 PZ |
1 | /* |
2 | * trace event based perf counter profiling | |
3 | * | |
4 | * Copyright (C) 2009 Red Hat Inc, Peter Zijlstra <pzijlstr@redhat.com> | |
5 | * | |
6 | */ | |
7 | ||
558e6547 | 8 | #include <linux/module.h> |
ac199db0 PZ |
9 | #include "trace.h" |
10 | ||
20ab4425 | 11 | |
ce71b9df | 12 | char *perf_trace_buf; |
444a2a3b | 13 | EXPORT_SYMBOL_GPL(perf_trace_buf); |
05bafda8 | 14 | |
ce71b9df | 15 | char *perf_trace_buf_nmi; |
444a2a3b | 16 | EXPORT_SYMBOL_GPL(perf_trace_buf_nmi); |
20ab4425 | 17 | |
ce71b9df FW |
18 | typedef typeof(char [FTRACE_MAX_PROFILE_SIZE]) perf_trace_t ; |
19 | ||
20ab4425 FW |
20 | /* Count the events in use (per event id, not per instance) */ |
21 | static int total_profile_count; | |
22 | ||
e5e25cf4 FW |
23 | static int ftrace_profile_enable_event(struct ftrace_event_call *event) |
24 | { | |
ce71b9df | 25 | char *buf; |
20ab4425 FW |
26 | int ret = -ENOMEM; |
27 | ||
e00bf2ec | 28 | if (event->profile_count++ > 0) |
e5e25cf4 FW |
29 | return 0; |
30 | ||
fe8e5b5a | 31 | if (!total_profile_count) { |
ce71b9df | 32 | buf = (char *)alloc_percpu(perf_trace_t); |
20ab4425 FW |
33 | if (!buf) |
34 | goto fail_buf; | |
35 | ||
444a2a3b | 36 | rcu_assign_pointer(perf_trace_buf, buf); |
20ab4425 | 37 | |
ce71b9df | 38 | buf = (char *)alloc_percpu(perf_trace_t); |
20ab4425 FW |
39 | if (!buf) |
40 | goto fail_buf_nmi; | |
41 | ||
444a2a3b | 42 | rcu_assign_pointer(perf_trace_buf_nmi, buf); |
20ab4425 FW |
43 | } |
44 | ||
d7a4b414 | 45 | ret = event->profile_enable(event); |
fe8e5b5a FW |
46 | if (!ret) { |
47 | total_profile_count++; | |
20ab4425 | 48 | return 0; |
fe8e5b5a | 49 | } |
20ab4425 | 50 | |
20ab4425 | 51 | fail_buf_nmi: |
fe8e5b5a | 52 | if (!total_profile_count) { |
444a2a3b FW |
53 | free_percpu(perf_trace_buf_nmi); |
54 | free_percpu(perf_trace_buf); | |
55 | perf_trace_buf_nmi = NULL; | |
56 | perf_trace_buf = NULL; | |
fe8e5b5a | 57 | } |
20ab4425 | 58 | fail_buf: |
e00bf2ec | 59 | event->profile_count--; |
20ab4425 FW |
60 | |
61 | return ret; | |
e5e25cf4 FW |
62 | } |
63 | ||
ac199db0 PZ |
64 | int ftrace_profile_enable(int event_id) |
65 | { | |
66 | struct ftrace_event_call *event; | |
20c8928a | 67 | int ret = -EINVAL; |
ac199db0 | 68 | |
20c8928a | 69 | mutex_lock(&event_mutex); |
a59fd602 | 70 | list_for_each_entry(event, &ftrace_events, list) { |
558e6547 LZ |
71 | if (event->id == event_id && event->profile_enable && |
72 | try_module_get(event->mod)) { | |
e5e25cf4 | 73 | ret = ftrace_profile_enable_event(event); |
20c8928a LZ |
74 | break; |
75 | } | |
ac199db0 | 76 | } |
20c8928a | 77 | mutex_unlock(&event_mutex); |
ac199db0 | 78 | |
20c8928a | 79 | return ret; |
ac199db0 PZ |
80 | } |
81 | ||
e5e25cf4 FW |
82 | static void ftrace_profile_disable_event(struct ftrace_event_call *event) |
83 | { | |
ce71b9df | 84 | char *buf, *nmi_buf; |
20ab4425 | 85 | |
e00bf2ec | 86 | if (--event->profile_count > 0) |
e5e25cf4 FW |
87 | return; |
88 | ||
d7a4b414 | 89 | event->profile_disable(event); |
20ab4425 FW |
90 | |
91 | if (!--total_profile_count) { | |
444a2a3b FW |
92 | buf = perf_trace_buf; |
93 | rcu_assign_pointer(perf_trace_buf, NULL); | |
20ab4425 | 94 | |
444a2a3b FW |
95 | nmi_buf = perf_trace_buf_nmi; |
96 | rcu_assign_pointer(perf_trace_buf_nmi, NULL); | |
20ab4425 FW |
97 | |
98 | /* | |
99 | * Ensure every events in profiling have finished before | |
100 | * releasing the buffers | |
101 | */ | |
102 | synchronize_sched(); | |
103 | ||
104 | free_percpu(buf); | |
105 | free_percpu(nmi_buf); | |
106 | } | |
e5e25cf4 FW |
107 | } |
108 | ||
ac199db0 PZ |
109 | void ftrace_profile_disable(int event_id) |
110 | { | |
111 | struct ftrace_event_call *event; | |
112 | ||
20c8928a | 113 | mutex_lock(&event_mutex); |
a59fd602 | 114 | list_for_each_entry(event, &ftrace_events, list) { |
20c8928a | 115 | if (event->id == event_id) { |
e5e25cf4 | 116 | ftrace_profile_disable_event(event); |
558e6547 | 117 | module_put(event->mod); |
20c8928a LZ |
118 | break; |
119 | } | |
ac199db0 | 120 | } |
20c8928a | 121 | mutex_unlock(&event_mutex); |
ac199db0 | 122 | } |