LXR linux/kernel/trace/trace_sched

   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/kallsyms.h>
   9#include <linux/uaccess.h>
  10#include <linux/ftrace.h>
  11#include <trace/events/sched.h>
  12
  13#include "trace.h"
  14
  15static int                      sched_ref;
  16static DEFINE_MUTEX(sched_register_mutex);
  17
  18static void
  19probe_sched_switch(void *ignore, bool preempt,
  20                   struct task_struct *prev, struct task_struct *next)
  21{
  22        if (unlikely(!sched_ref))
  23                return;
  24
  25        tracing_record_cmdline(prev);
  26        tracing_record_cmdline(next);
  27}
  28
  29static void
  30probe_sched_wakeup(void *ignore, struct task_struct *wakee)
  31{
  32        if (unlikely(!sched_ref))
  33                return;
  34
  35        tracing_record_cmdline(current);
  36}
  37
  38static int tracing_sched_register(void)
  39{
  40        int ret;
  41
  42        ret = register_trace_sched_wakeup(probe_sched_wakeup, NULL);
  43        if (ret) {
  44                pr_info("wakeup trace: Couldn't activate tracepoint"
  45                        " probe to kernel_sched_wakeup\n");
  46                return ret;
  47        }
  48
  49        ret = register_trace_sched_wakeup_new(probe_sched_wakeup, NULL);
  50        if (ret) {
  51                pr_info("wakeup trace: Couldn't activate tracepoint"
  52                        " probe to kernel_sched_wakeup_new\n");
  53                goto fail_deprobe;
  54        }
  55
  56        ret = register_trace_sched_switch(probe_sched_switch, NULL);
  57        if (ret) {
  58                pr_info("sched trace: Couldn't activate tracepoint"
  59                        " probe to kernel_sched_switch\n");
  60                goto fail_deprobe_wake_new;
  61        }
  62
  63        return ret;
  64fail_deprobe_wake_new:
  65        unregister_trace_sched_wakeup_new(probe_sched_wakeup, NULL);
  66fail_deprobe:
  67        unregister_trace_sched_wakeup(probe_sched_wakeup, NULL);
  68        return ret;
  69}
  70
  71static void tracing_sched_unregister(void)
  72{
  73        unregister_trace_sched_switch(probe_sched_switch, NULL);
  74        unregister_trace_sched_wakeup_new(probe_sched_wakeup, NULL);
  75        unregister_trace_sched_wakeup(probe_sched_wakeup, NULL);
  76}
  77
  78static void tracing_start_sched_switch(void)
  79{
  80        mutex_lock(&sched_register_mutex);
  81        if (!(sched_ref++))
  82                tracing_sched_register();
  83        mutex_unlock(&sched_register_mutex);
  84}
  85
  86static void tracing_stop_sched_switch(void)
  87{
  88        mutex_lock(&sched_register_mutex);
  89        if (!(--sched_ref))
  90                tracing_sched_unregister();
  91        mutex_unlock(&sched_register_mutex);
  92}
  93
  94void tracing_start_cmdline_record(void)
  95{
  96        tracing_start_sched_switch();
  97}
  98
  99void tracing_stop_cmdline_record(void)
 100{
 101        tracing_stop_sched_switch();
 102}
 103