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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 | #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],
tsk_cpus_allowed(current));
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);
void foo_bar_reg(void)
{
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.
*/
mutex_lock(&thread_mutex);
simple_tsk_fn = kthread_run(simple_thread_fn, NULL, "event-sample-fn");
mutex_unlock(&thread_mutex);
}
void foo_bar_unreg(void)
{
pr_info("Killing thread for foo_bar_fn\n");
/* protect against module unloading */
mutex_lock(&thread_mutex);
if (simple_tsk_fn)
kthread_stop(simple_tsk_fn);
simple_tsk_fn = NULL;
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");
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