tracing/kprobes: Increment probe hit-count even if it is used by perf
[linux-3.10.git] / kernel / trace / trace_sched_switch.c
1 /*
2  * trace context switch
3  *
4  * Copyright (C) 2007 Steven Rostedt <srostedt@redhat.com>
5  *
6  */
7 #include <linux/module.h>
8 #include <linux/fs.h>
9 #include <linux/debugfs.h>
10 #include <linux/kallsyms.h>
11 #include <linux/uaccess.h>
12 #include <linux/ftrace.h>
13 #include <trace/events/sched.h>
14
15 #include "trace.h"
16
17 static struct trace_array       *ctx_trace;
18 static int __read_mostly        tracer_enabled;
19 static int                      sched_ref;
20 static DEFINE_MUTEX(sched_register_mutex);
21 static int                      sched_stopped;
22
23
24 void
25 tracing_sched_switch_trace(struct trace_array *tr,
26                            struct task_struct *prev,
27                            struct task_struct *next,
28                            unsigned long flags, int pc)
29 {
30         struct ftrace_event_call *call = &event_context_switch;
31         struct ring_buffer *buffer = tr->trace_buffer.buffer;
32         struct ring_buffer_event *event;
33         struct ctx_switch_entry *entry;
34
35         event = trace_buffer_lock_reserve(buffer, TRACE_CTX,
36                                           sizeof(*entry), flags, pc);
37         if (!event)
38                 return;
39         entry   = ring_buffer_event_data(event);
40         entry->prev_pid                 = prev->pid;
41         entry->prev_prio                = prev->prio;
42         entry->prev_state               = prev->state;
43         entry->next_pid                 = next->pid;
44         entry->next_prio                = next->prio;
45         entry->next_state               = next->state;
46         entry->next_cpu = task_cpu(next);
47
48         if (!filter_check_discard(call, entry, buffer, event))
49                 trace_buffer_unlock_commit(buffer, event, flags, pc);
50 }
51
52 static void
53 probe_sched_switch(void *ignore, struct task_struct *prev, struct task_struct *next)
54 {
55         struct trace_array_cpu *data;
56         unsigned long flags;
57         int cpu;
58         int pc;
59
60         if (unlikely(!sched_ref))
61                 return;
62
63         tracing_record_cmdline(prev);
64         tracing_record_cmdline(next);
65
66         if (!tracer_enabled || sched_stopped)
67                 return;
68
69         pc = preempt_count();
70         local_irq_save(flags);
71         cpu = raw_smp_processor_id();
72         data = per_cpu_ptr(ctx_trace->trace_buffer.data, cpu);
73
74         if (likely(!atomic_read(&data->disabled)))
75                 tracing_sched_switch_trace(ctx_trace, prev, next, flags, pc);
76
77         local_irq_restore(flags);
78 }
79
80 void
81 tracing_sched_wakeup_trace(struct trace_array *tr,
82                            struct task_struct *wakee,
83                            struct task_struct *curr,
84                            unsigned long flags, int pc)
85 {
86         struct ftrace_event_call *call = &event_wakeup;
87         struct ring_buffer_event *event;
88         struct ctx_switch_entry *entry;
89         struct ring_buffer *buffer = tr->trace_buffer.buffer;
90
91         event = trace_buffer_lock_reserve(buffer, TRACE_WAKE,
92                                           sizeof(*entry), flags, pc);
93         if (!event)
94                 return;
95         entry   = ring_buffer_event_data(event);
96         entry->prev_pid                 = curr->pid;
97         entry->prev_prio                = curr->prio;
98         entry->prev_state               = curr->state;
99         entry->next_pid                 = wakee->pid;
100         entry->next_prio                = wakee->prio;
101         entry->next_state               = wakee->state;
102         entry->next_cpu                 = task_cpu(wakee);
103
104         if (!filter_check_discard(call, entry, buffer, event))
105                 trace_buffer_unlock_commit(buffer, event, flags, pc);
106 }
107
108 static void
109 probe_sched_wakeup(void *ignore, struct task_struct *wakee, int success)
110 {
111         struct trace_array_cpu *data;
112         unsigned long flags;
113         int cpu, pc;
114
115         if (unlikely(!sched_ref))
116                 return;
117
118         tracing_record_cmdline(current);
119
120         if (!tracer_enabled || sched_stopped)
121                 return;
122
123         pc = preempt_count();
124         local_irq_save(flags);
125         cpu = raw_smp_processor_id();
126         data = per_cpu_ptr(ctx_trace->trace_buffer.data, cpu);
127
128         if (likely(!atomic_read(&data->disabled)))
129                 tracing_sched_wakeup_trace(ctx_trace, wakee, current,
130                                            flags, pc);
131
132         local_irq_restore(flags);
133 }
134
135 static int tracing_sched_register(void)
136 {
137         int ret;
138
139         ret = register_trace_sched_wakeup(probe_sched_wakeup, NULL);
140         if (ret) {
141                 pr_info("wakeup trace: Couldn't activate tracepoint"
142                         " probe to kernel_sched_wakeup\n");
143                 return ret;
144         }
145
146         ret = register_trace_sched_wakeup_new(probe_sched_wakeup, NULL);
147         if (ret) {
148                 pr_info("wakeup trace: Couldn't activate tracepoint"
149                         " probe to kernel_sched_wakeup_new\n");
150                 goto fail_deprobe;
151         }
152
153         ret = register_trace_sched_switch(probe_sched_switch, NULL);
154         if (ret) {
155                 pr_info("sched trace: Couldn't activate tracepoint"
156                         " probe to kernel_sched_switch\n");
157                 goto fail_deprobe_wake_new;
158         }
159
160         return ret;
161 fail_deprobe_wake_new:
162         unregister_trace_sched_wakeup_new(probe_sched_wakeup, NULL);
163 fail_deprobe:
164         unregister_trace_sched_wakeup(probe_sched_wakeup, NULL);
165         return ret;
166 }
167
168 static void tracing_sched_unregister(void)
169 {
170         unregister_trace_sched_switch(probe_sched_switch, NULL);
171         unregister_trace_sched_wakeup_new(probe_sched_wakeup, NULL);
172         unregister_trace_sched_wakeup(probe_sched_wakeup, NULL);
173 }
174
175 static void tracing_start_sched_switch(void)
176 {
177         mutex_lock(&sched_register_mutex);
178         if (!(sched_ref++))
179                 tracing_sched_register();
180         mutex_unlock(&sched_register_mutex);
181 }
182
183 static void tracing_stop_sched_switch(void)
184 {
185         mutex_lock(&sched_register_mutex);
186         if (!(--sched_ref))
187                 tracing_sched_unregister();
188         mutex_unlock(&sched_register_mutex);
189 }
190
191 void tracing_start_cmdline_record(void)
192 {
193         tracing_start_sched_switch();
194 }
195
196 void tracing_stop_cmdline_record(void)
197 {
198         tracing_stop_sched_switch();
199 }
200
201 /**
202  * tracing_start_sched_switch_record - start tracing context switches
203  *
204  * Turns on context switch tracing for a tracer.
205  */
206 void tracing_start_sched_switch_record(void)
207 {
208         if (unlikely(!ctx_trace)) {
209                 WARN_ON(1);
210                 return;
211         }
212
213         tracing_start_sched_switch();
214
215         mutex_lock(&sched_register_mutex);
216         tracer_enabled++;
217         mutex_unlock(&sched_register_mutex);
218 }
219
220 /**
221  * tracing_stop_sched_switch_record - start tracing context switches
222  *
223  * Turns off context switch tracing for a tracer.
224  */
225 void tracing_stop_sched_switch_record(void)
226 {
227         mutex_lock(&sched_register_mutex);
228         tracer_enabled--;
229         WARN_ON(tracer_enabled < 0);
230         mutex_unlock(&sched_register_mutex);
231
232         tracing_stop_sched_switch();
233 }
234
235 /**
236  * tracing_sched_switch_assign_trace - assign a trace array for ctx switch
237  * @tr: trace array pointer to assign
238  *
239  * Some tracers might want to record the context switches in their
240  * trace. This function lets those tracers assign the trace array
241  * to use.
242  */
243 void tracing_sched_switch_assign_trace(struct trace_array *tr)
244 {
245         ctx_trace = tr;
246 }
247