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
15 static int sched_ref;
16 static DEFINE_MUTEX(sched_register_mutex);
17
18 static void
probe_sched_switch(void * ignore,bool preempt,struct task_struct * prev,struct task_struct * next)19 probe_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
29 static void
probe_sched_wakeup(void * ignore,struct task_struct * wakee)30 probe_sched_wakeup(void *ignore, struct task_struct *wakee)
31 {
32 if (unlikely(!sched_ref))
33 return;
34
35 tracing_record_cmdline(current);
36 }
37
tracing_sched_register(void)38 static 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;
64 fail_deprobe_wake_new:
65 unregister_trace_sched_wakeup_new(probe_sched_wakeup, NULL);
66 fail_deprobe:
67 unregister_trace_sched_wakeup(probe_sched_wakeup, NULL);
68 return ret;
69 }
70
tracing_sched_unregister(void)71 static 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
tracing_start_sched_switch(void)78 static 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
tracing_stop_sched_switch(void)86 static 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
tracing_start_cmdline_record(void)94 void tracing_start_cmdline_record(void)
95 {
96 tracing_start_sched_switch();
97 }
98
tracing_stop_cmdline_record(void)99 void tracing_stop_cmdline_record(void)
100 {
101 tracing_stop_sched_switch();
102 }
103