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-rw-r--r--samples/trace_events/trace-events-sample.c80
1 files changed, 79 insertions, 1 deletions
diff --git a/samples/trace_events/trace-events-sample.c b/samples/trace_events/trace-events-sample.c
index aabc4e9..880a7d1 100644
--- a/samples/trace_events/trace-events-sample.c
+++ b/samples/trace_events/trace-events-sample.c
@@ -10,12 +10,38 @@
#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);
- trace_foo_bar("hello", cnt);
+
+ 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)
@@ -29,6 +55,53 @@ static int simple_thread(void *arg)
}
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)
{
@@ -42,6 +115,11 @@ static int __init trace_event_init(void)
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);
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