| #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], |
| ¤t->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"); |