1#include <linux/module.h>
 2#include <linux/kthread.h>
 3
 4/*
 5 * Any file that uses trace points, must include the header.
 6 * But only one file, must include the header by defining
 7 * CREATE_TRACE_POINTS first.  This will make the C code that
 8 * creates the handles for the trace points.
 9 */
10#define CREATE_TRACE_POINTS
11#include "trace-events-sample.h"
12
 
 
 
 
 
 
 
13
14static void simple_thread_func(int cnt)
15{
 
 
 
 
16	set_current_state(TASK_INTERRUPTIBLE);
17	schedule_timeout(HZ);
18	trace_foo_bar("hello", cnt);
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
19}
20
21static int simple_thread(void *arg)
22{
23	int cnt = 0;
24
25	while (!kthread_should_stop())
26		simple_thread_func(cnt++);
27
28	return 0;
29}
30
31static struct task_struct *simple_tsk;
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
32
33static int __init trace_event_init(void)
34{
35	simple_tsk = kthread_run(simple_thread, NULL, "event-sample");
36	if (IS_ERR(simple_tsk))
37		return -1;
38
39	return 0;
40}
41
42static void __exit trace_event_exit(void)
43{
44	kthread_stop(simple_tsk);
 
 
 
 
 
45}
46
47module_init(trace_event_init);
48module_exit(trace_event_exit);
49
50MODULE_AUTHOR("Steven Rostedt");
51MODULE_DESCRIPTION("trace-events-sample");
52MODULE_LICENSE("GPL");

  1#include <linux/module.h>
  2#include <linux/kthread.h>
  3
  4/*
  5 * Any file that uses trace points, must include the header.
  6 * But only one file, must include the header by defining
  7 * CREATE_TRACE_POINTS first.  This will make the C code that
  8 * creates the handles for the trace points.
  9 */
 10#define CREATE_TRACE_POINTS
 11#include "trace-events-sample.h"
 12
 13static const char *random_strings[] = {
 14	"Mother Goose",
 15	"Snoopy",
 16	"Gandalf",
 17	"Frodo",
 18	"One ring to rule them all"
 19};
 20
 21static void simple_thread_func(int cnt)
 22{
 23	int array[6];
 24	int len = cnt % 5;
 25	int i;
 26
 27	set_current_state(TASK_INTERRUPTIBLE);
 28	schedule_timeout(HZ);
 29
 30	for (i = 0; i < len; i++)
 31		array[i] = i + 1;
 32	array[i] = 0;
 33
 34	/* Silly tracepoints */
 35	trace_foo_bar("hello", cnt, array, random_strings[len],
 36		      &current->cpus_allowed);
 37
 38	trace_foo_with_template_simple("HELLO", cnt);
 39
 40	trace_foo_bar_with_cond("Some times print", cnt);
 41
 42	trace_foo_with_template_cond("prints other times", cnt);
 43
 44	trace_foo_with_template_print("I have to be different", cnt);
 45}
 46
 47static int simple_thread(void *arg)
 48{
 49	int cnt = 0;
 50
 51	while (!kthread_should_stop())
 52		simple_thread_func(cnt++);
 53
 54	return 0;
 55}
 56
 57static struct task_struct *simple_tsk;
 58static struct task_struct *simple_tsk_fn;
 59
 60static void simple_thread_func_fn(int cnt)
 61{
 62	set_current_state(TASK_INTERRUPTIBLE);
 63	schedule_timeout(HZ);
 64
 65	/* More silly tracepoints */
 66	trace_foo_bar_with_fn("Look at me", cnt);
 67	trace_foo_with_template_fn("Look at me too", cnt);
 68}
 69
 70static int simple_thread_fn(void *arg)
 71{
 72	int cnt = 0;
 73
 74	while (!kthread_should_stop())
 75		simple_thread_func_fn(cnt++);
 76
 77	return 0;
 78}
 79
 80static DEFINE_MUTEX(thread_mutex);
 81static int simple_thread_cnt;
 82
 83int foo_bar_reg(void)
 84{
 85	mutex_lock(&thread_mutex);
 86	if (simple_thread_cnt++)
 87		goto out;
 88
 89	pr_info("Starting thread for foo_bar_fn\n");
 90	/*
 91	 * We shouldn't be able to start a trace when the module is
 92	 * unloading (there's other locks to prevent that). But
 93	 * for consistency sake, we still take the thread_mutex.
 94	 */
 95	simple_tsk_fn = kthread_run(simple_thread_fn, NULL, "event-sample-fn");
 96 out:
 97	mutex_unlock(&thread_mutex);
 98	return 0;
 99}
100
101void foo_bar_unreg(void)
102{
103	mutex_lock(&thread_mutex);
104	if (--simple_thread_cnt)
105		goto out;
106
107	pr_info("Killing thread for foo_bar_fn\n");
108	if (simple_tsk_fn)
109		kthread_stop(simple_tsk_fn);
110	simple_tsk_fn = NULL;
111 out:
112	mutex_unlock(&thread_mutex);
113}
114
115static int __init trace_event_init(void)
116{
117	simple_tsk = kthread_run(simple_thread, NULL, "event-sample");
118	if (IS_ERR(simple_tsk))
119		return -1;
120
121	return 0;
122}
123
124static void __exit trace_event_exit(void)
125{
126	kthread_stop(simple_tsk);
127	mutex_lock(&thread_mutex);
128	if (simple_tsk_fn)
129		kthread_stop(simple_tsk_fn);
130	simple_tsk_fn = NULL;
131	mutex_unlock(&thread_mutex);
132}
133
134module_init(trace_event_init);
135module_exit(trace_event_exit);
136
137MODULE_AUTHOR("Steven Rostedt");
138MODULE_DESCRIPTION("trace-events-sample");
139MODULE_LICENSE("GPL");