USB: re-enable interface after driver unbinds
[linux-2.6/mini2440.git] / kernel / trace / trace_sched_switch.c
blobdf175cb4564f0a38ff3911f3015dd9a1866c7620
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/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);
22 static void
23 probe_sched_switch(struct rq *__rq, struct task_struct *prev,
24 struct task_struct *next)
26 struct trace_array_cpu *data;
27 unsigned long flags;
28 int cpu;
29 int pc;
31 if (!sched_ref)
32 return;
34 tracing_record_cmdline(prev);
35 tracing_record_cmdline(next);
37 if (!tracer_enabled)
38 return;
40 pc = preempt_count();
41 local_irq_save(flags);
42 cpu = raw_smp_processor_id();
43 data = ctx_trace->data[cpu];
45 if (likely(!atomic_read(&data->disabled)))
46 tracing_sched_switch_trace(ctx_trace, data, prev, next, flags, pc);
48 local_irq_restore(flags);
51 static void
52 probe_sched_wakeup(struct rq *__rq, struct task_struct *wakee, int success)
54 struct trace_array_cpu *data;
55 unsigned long flags;
56 int cpu, pc;
58 if (!likely(tracer_enabled))
59 return;
61 pc = preempt_count();
62 tracing_record_cmdline(current);
64 local_irq_save(flags);
65 cpu = raw_smp_processor_id();
66 data = ctx_trace->data[cpu];
68 if (likely(!atomic_read(&data->disabled)))
69 tracing_sched_wakeup_trace(ctx_trace, data, wakee, current,
70 flags, pc);
72 local_irq_restore(flags);
75 static int tracing_sched_register(void)
77 int ret;
79 ret = register_trace_sched_wakeup(probe_sched_wakeup);
80 if (ret) {
81 pr_info("wakeup trace: Couldn't activate tracepoint"
82 " probe to kernel_sched_wakeup\n");
83 return ret;
86 ret = register_trace_sched_wakeup_new(probe_sched_wakeup);
87 if (ret) {
88 pr_info("wakeup trace: Couldn't activate tracepoint"
89 " probe to kernel_sched_wakeup_new\n");
90 goto fail_deprobe;
93 ret = register_trace_sched_switch(probe_sched_switch);
94 if (ret) {
95 pr_info("sched trace: Couldn't activate tracepoint"
96 " probe to kernel_sched_schedule\n");
97 goto fail_deprobe_wake_new;
100 return ret;
101 fail_deprobe_wake_new:
102 unregister_trace_sched_wakeup_new(probe_sched_wakeup);
103 fail_deprobe:
104 unregister_trace_sched_wakeup(probe_sched_wakeup);
105 return ret;
108 static void tracing_sched_unregister(void)
110 unregister_trace_sched_switch(probe_sched_switch);
111 unregister_trace_sched_wakeup_new(probe_sched_wakeup);
112 unregister_trace_sched_wakeup(probe_sched_wakeup);
115 static void tracing_start_sched_switch(void)
117 mutex_lock(&sched_register_mutex);
118 if (!(sched_ref++))
119 tracing_sched_register();
120 mutex_unlock(&sched_register_mutex);
123 static void tracing_stop_sched_switch(void)
125 mutex_lock(&sched_register_mutex);
126 if (!(--sched_ref))
127 tracing_sched_unregister();
128 mutex_unlock(&sched_register_mutex);
131 void tracing_start_cmdline_record(void)
133 tracing_start_sched_switch();
136 void tracing_stop_cmdline_record(void)
138 tracing_stop_sched_switch();
142 * tracing_start_sched_switch_record - start tracing context switches
144 * Turns on context switch tracing for a tracer.
146 void tracing_start_sched_switch_record(void)
148 if (unlikely(!ctx_trace)) {
149 WARN_ON(1);
150 return;
153 tracing_start_sched_switch();
155 mutex_lock(&sched_register_mutex);
156 tracer_enabled++;
157 mutex_unlock(&sched_register_mutex);
161 * tracing_stop_sched_switch_record - start tracing context switches
163 * Turns off context switch tracing for a tracer.
165 void tracing_stop_sched_switch_record(void)
167 mutex_lock(&sched_register_mutex);
168 tracer_enabled--;
169 WARN_ON(tracer_enabled < 0);
170 mutex_unlock(&sched_register_mutex);
172 tracing_stop_sched_switch();
176 * tracing_sched_switch_assign_trace - assign a trace array for ctx switch
177 * @tr: trace array pointer to assign
179 * Some tracers might want to record the context switches in their
180 * trace. This function lets those tracers assign the trace array
181 * to use.
183 void tracing_sched_switch_assign_trace(struct trace_array *tr)
185 ctx_trace = tr;
188 static void start_sched_trace(struct trace_array *tr)
190 tracing_reset_online_cpus(tr);
191 tracing_start_sched_switch_record();
194 static void stop_sched_trace(struct trace_array *tr)
196 tracing_stop_sched_switch_record();
199 static int sched_switch_trace_init(struct trace_array *tr)
201 ctx_trace = tr;
202 start_sched_trace(tr);
203 return 0;
206 static void sched_switch_trace_reset(struct trace_array *tr)
208 if (sched_ref)
209 stop_sched_trace(tr);
212 static void sched_switch_trace_start(struct trace_array *tr)
214 tracing_reset_online_cpus(tr);
215 tracing_start_sched_switch();
218 static void sched_switch_trace_stop(struct trace_array *tr)
220 tracing_stop_sched_switch();
223 static struct tracer sched_switch_trace __read_mostly =
225 .name = "sched_switch",
226 .init = sched_switch_trace_init,
227 .reset = sched_switch_trace_reset,
228 .start = sched_switch_trace_start,
229 .stop = sched_switch_trace_stop,
230 #ifdef CONFIG_FTRACE_SELFTEST
231 .selftest = trace_selftest_startup_sched_switch,
232 #endif
235 __init static int init_sched_switch_trace(void)
237 return register_tracer(&sched_switch_trace);
239 device_initcall(init_sched_switch_trace);