[mirror_ubuntu-bionic-kernel.git] / samples / trace_events / trace-events-sample.c

#include <linux/module.h>
#include <linux/kthread.h>

/*
 * Any file that uses trace points, must include the header.
 * But only one file, must include the header by defining
 * CREATE_TRACE_POINTS first.  This will make the C code that
 * creates the handles for the trace points.
 */
#define CREATE_TRACE_POINTS
#include "trace-events-sample.h"

static const char *random_strings[] = {
	"Mother Goose",
	"Snoopy",
	"Gandalf",
	"Frodo",
	"One ring to rule them all"
};

static void simple_thread_func(int cnt)
{
	int array[6];
	int len = cnt % 5;
	int i;

	set_current_state(TASK_INTERRUPTIBLE);
	schedule_timeout(HZ);

	for (i = 0; i < len; i++)
		array[i] = i + 1;
	array[i] = 0;

	/* Silly tracepoints */
	trace_foo_bar("hello", cnt, array, random_strings[len],
		      &current->cpus_allowed);

	trace_foo_with_template_simple("HELLO", cnt);

	trace_foo_bar_with_cond("Some times print", cnt);

	trace_foo_with_template_cond("prints other times", cnt);

	trace_foo_with_template_print("I have to be different", cnt);
}

static int simple_thread(void *arg)
{
	int cnt = 0;

	while (!kthread_should_stop())
		simple_thread_func(cnt++);

	return 0;
}

static struct task_struct *simple_tsk;
static struct task_struct *simple_tsk_fn;

static void simple_thread_func_fn(int cnt)
{
	set_current_state(TASK_INTERRUPTIBLE);
	schedule_timeout(HZ);

	/* More silly tracepoints */
	trace_foo_bar_with_fn("Look at me", cnt);
	trace_foo_with_template_fn("Look at me too", cnt);
}

static int simple_thread_fn(void *arg)
{
	int cnt = 0;

	while (!kthread_should_stop())
		simple_thread_func_fn(cnt++);

	return 0;
}

static DEFINE_MUTEX(thread_mutex);
static bool simple_thread_cnt;

int foo_bar_reg(void)
{
	mutex_lock(&thread_mutex);
	if (simple_thread_cnt++)
		goto out;

	pr_info("Starting thread for foo_bar_fn\n");
	/*
	 * We shouldn't be able to start a trace when the module is
	 * unloading (there's other locks to prevent that). But
	 * for consistency sake, we still take the thread_mutex.
	 */
	simple_tsk_fn = kthread_run(simple_thread_fn, NULL, "event-sample-fn");
 out:
	mutex_unlock(&thread_mutex);
	return 0;
}

void foo_bar_unreg(void)
{
	mutex_lock(&thread_mutex);
	if (--simple_thread_cnt)
		goto out;

	pr_info("Killing thread for foo_bar_fn\n");
	if (simple_tsk_fn)
		kthread_stop(simple_tsk_fn);
	simple_tsk_fn = NULL;
 out:
	mutex_unlock(&thread_mutex);
}

static int __init trace_event_init(void)
{
	simple_tsk = kthread_run(simple_thread, NULL, "event-sample");
	if (IS_ERR(simple_tsk))
		return -1;

	return 0;
}

static void __exit trace_event_exit(void)
{
	kthread_stop(simple_tsk);
	mutex_lock(&thread_mutex);
	if (simple_tsk_fn)
		kthread_stop(simple_tsk_fn);
	simple_tsk_fn = NULL;
	mutex_unlock(&thread_mutex);
}

module_init(trace_event_init);
module_exit(trace_event_exit);

MODULE_AUTHOR("Steven Rostedt");
MODULE_DESCRIPTION("trace-events-sample");
MODULE_LICENSE("GPL");
Commit	Line	Data
9cfe06f8 SR	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
4e20e3a6 SRRH	13	static const char *random_strings[] = {
	14	"Mother Goose",
	15	"Snoopy",
	16	"Gandalf",
	17	"Frodo",
	18	"One ring to rule them all"
	19	};
9cfe06f8 SR	20
	21	static void simple_thread_func(int cnt)
	22	{
4e20e3a6 SRRH	23	int array[6];
	24	int len = cnt % 5;
	25	int i;
	26
9cfe06f8 SR	27	set_current_state(TASK_INTERRUPTIBLE);
9cfe06f8 SR	28	schedule_timeout(HZ);
4e20e3a6 SRRH	29
	30	for (i = 0; i < len; i++)
	31	array[i] = i + 1;
	32	array[i] = 0;
	33
c4c7eb29	34	/* Silly tracepoints */
4e20e3a6	35	trace_foo_bar("hello", cnt, array, random_strings[len],
0c98d344	36	&current->cpus_allowed);
c4c7eb29	37
7496946a SRRH	38	trace_foo_with_template_simple("HELLO", cnt);
7496946a SRRH	39
c4c7eb29	40	trace_foo_bar_with_cond("Some times print", cnt);
7496946a SRRH	41
	42	trace_foo_with_template_cond("prints other times", cnt);
	43
	44	trace_foo_with_template_print("I have to be different", cnt);
9cfe06f8 SR	45	}
	46
	47	static 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
	57	static struct task_struct *simple_tsk;
6adc13f8 SRRH	58	static struct task_struct *simple_tsk_fn;
	59
	60	static 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);
7496946a	67	trace_foo_with_template_fn("Look at me too", cnt);
6adc13f8 SRRH	68	}
	69
	70	static 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
	80	static DEFINE_MUTEX(thread_mutex);
6575257c	81	static bool simple_thread_cnt;
6adc13f8	82
8cf868af	83	int foo_bar_reg(void)
6adc13f8	84	{
6575257c SRV	85	mutex_lock(&thread_mutex);
	86	if (simple_thread_cnt++)
	87	goto out;
	88
6adc13f8 SRRH	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	*/
6adc13f8	95	simple_tsk_fn = kthread_run(simple_thread_fn, NULL, "event-sample-fn");
6575257c	96	out:
6adc13f8	97	mutex_unlock(&thread_mutex);
8cf868af	98	return 0;
6adc13f8 SRRH	99	}
	100
	101	void foo_bar_unreg(void)
	102	{
6adc13f8	103	mutex_lock(&thread_mutex);
6575257c SRV	104	if (--simple_thread_cnt)
	105	goto out;
	106
	107	pr_info("Killing thread for foo_bar_fn\n");
6adc13f8 SRRH	108	if (simple_tsk_fn)
	109	kthread_stop(simple_tsk_fn);
	110	simple_tsk_fn = NULL;
6575257c	111	out:
6adc13f8 SRRH	112	mutex_unlock(&thread_mutex);
6adc13f8 SRRH	113	}
9cfe06f8 SR	114
	115	static 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
	124	static void __exit trace_event_exit(void)
	125	{
	126	kthread_stop(simple_tsk);
6adc13f8 SRRH	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);
9cfe06f8 SR	132	}
	133
	134	module_init(trace_event_init);
	135	module_exit(trace_event_exit);
	136
	137	MODULE_AUTHOR("Steven Rostedt");
	138	MODULE_DESCRIPTION("trace-events-sample");
	139	MODULE_LICENSE("GPL");