Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/dtor/input
[linux-btrfs-devel.git] / kernel / trace / trace_sched_switch.c
blob7e62c0a18456ebbad8fc66a83a9f2578a081e201
1 /*
2 * trace context switch
4 * Copyright (C) 2007 Steven Rostedt <srostedt@redhat.com>
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>
15 #include "trace.h"
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;
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)
30 struct ftrace_event_call *call = &event_context_switch;
31 struct ring_buffer *buffer = tr->buffer;
32 struct ring_buffer_event *event;
33 struct ctx_switch_entry *entry;
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);
48 if (!filter_check_discard(call, entry, buffer, event))
49 trace_buffer_unlock_commit(buffer, event, flags, pc);
52 static void
53 probe_sched_switch(void *ignore, struct task_struct *prev, struct task_struct *next)
55 struct trace_array_cpu *data;
56 unsigned long flags;
57 int cpu;
58 int pc;
60 if (unlikely(!sched_ref))
61 return;
63 tracing_record_cmdline(prev);
64 tracing_record_cmdline(next);
66 if (!tracer_enabled || sched_stopped)
67 return;
69 pc = preempt_count();
70 local_irq_save(flags);
71 cpu = raw_smp_processor_id();
72 data = ctx_trace->data[cpu];
74 if (likely(!atomic_read(&data->disabled)))
75 tracing_sched_switch_trace(ctx_trace, prev, next, flags, pc);
77 local_irq_restore(flags);
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)
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->buffer;
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);
104 if (!filter_check_discard(call, entry, buffer, event))
105 ring_buffer_unlock_commit(buffer, event);
106 ftrace_trace_stack(tr->buffer, flags, 6, pc);
107 ftrace_trace_userstack(tr->buffer, flags, pc);
110 static void
111 probe_sched_wakeup(void *ignore, struct task_struct *wakee, int success)
113 struct trace_array_cpu *data;
114 unsigned long flags;
115 int cpu, pc;
117 if (unlikely(!sched_ref))
118 return;
120 tracing_record_cmdline(current);
122 if (!tracer_enabled || sched_stopped)
123 return;
125 pc = preempt_count();
126 local_irq_save(flags);
127 cpu = raw_smp_processor_id();
128 data = ctx_trace->data[cpu];
130 if (likely(!atomic_read(&data->disabled)))
131 tracing_sched_wakeup_trace(ctx_trace, wakee, current,
132 flags, pc);
134 local_irq_restore(flags);
137 static int tracing_sched_register(void)
139 int ret;
141 ret = register_trace_sched_wakeup(probe_sched_wakeup, NULL);
142 if (ret) {
143 pr_info("wakeup trace: Couldn't activate tracepoint"
144 " probe to kernel_sched_wakeup\n");
145 return ret;
148 ret = register_trace_sched_wakeup_new(probe_sched_wakeup, NULL);
149 if (ret) {
150 pr_info("wakeup trace: Couldn't activate tracepoint"
151 " probe to kernel_sched_wakeup_new\n");
152 goto fail_deprobe;
155 ret = register_trace_sched_switch(probe_sched_switch, NULL);
156 if (ret) {
157 pr_info("sched trace: Couldn't activate tracepoint"
158 " probe to kernel_sched_switch\n");
159 goto fail_deprobe_wake_new;
162 return ret;
163 fail_deprobe_wake_new:
164 unregister_trace_sched_wakeup_new(probe_sched_wakeup, NULL);
165 fail_deprobe:
166 unregister_trace_sched_wakeup(probe_sched_wakeup, NULL);
167 return ret;
170 static void tracing_sched_unregister(void)
172 unregister_trace_sched_switch(probe_sched_switch, NULL);
173 unregister_trace_sched_wakeup_new(probe_sched_wakeup, NULL);
174 unregister_trace_sched_wakeup(probe_sched_wakeup, NULL);
177 static void tracing_start_sched_switch(void)
179 mutex_lock(&sched_register_mutex);
180 if (!(sched_ref++))
181 tracing_sched_register();
182 mutex_unlock(&sched_register_mutex);
185 static void tracing_stop_sched_switch(void)
187 mutex_lock(&sched_register_mutex);
188 if (!(--sched_ref))
189 tracing_sched_unregister();
190 mutex_unlock(&sched_register_mutex);
193 void tracing_start_cmdline_record(void)
195 tracing_start_sched_switch();
198 void tracing_stop_cmdline_record(void)
200 tracing_stop_sched_switch();
204 * tracing_start_sched_switch_record - start tracing context switches
206 * Turns on context switch tracing for a tracer.
208 void tracing_start_sched_switch_record(void)
210 if (unlikely(!ctx_trace)) {
211 WARN_ON(1);
212 return;
215 tracing_start_sched_switch();
217 mutex_lock(&sched_register_mutex);
218 tracer_enabled++;
219 mutex_unlock(&sched_register_mutex);
223 * tracing_stop_sched_switch_record - start tracing context switches
225 * Turns off context switch tracing for a tracer.
227 void tracing_stop_sched_switch_record(void)
229 mutex_lock(&sched_register_mutex);
230 tracer_enabled--;
231 WARN_ON(tracer_enabled < 0);
232 mutex_unlock(&sched_register_mutex);
234 tracing_stop_sched_switch();
238 * tracing_sched_switch_assign_trace - assign a trace array for ctx switch
239 * @tr: trace array pointer to assign
241 * Some tracers might want to record the context switches in their
242 * trace. This function lets those tracers assign the trace array
243 * to use.
245 void tracing_sched_switch_assign_trace(struct trace_array *tr)
247 ctx_trace = tr;