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