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authorSteven Rostedt <rostedt@goodmis.org>2014-10-08 21:52:16 +0400
committerSteven Rostedt <rostedt@goodmis.org>2014-10-09 19:15:08 +0400
commitaddff1feb02b03cb766b9a611c6b2cebf29bc285 (patch)
treefaf54b05294f2feac72d62ebafb2fcbe959185e0 /kernel
parentfe0e01c77dd9f7a60916aec2149d8a1182baf63c (diff)
downloadlinux-addff1feb02b03cb766b9a611c6b2cebf29bc285.tar.xz
tracing: Clean up scheduling in trace_wakeup_test_thread()
Peter's new debugging tool triggers when tasks exit with !TASK_RUNNING. The code in trace_wakeup_test_thread() also has a single schedule() call that should be encompassed by a loop. This cleans up the code a little to make it a bit more robust and also makes the return exit properly with TASK_RUNNING. Link: http://lkml.kernel.org/p/20141008135216.76142204@gandalf.local.home Reported-by: Peter Zijlstra <peterz@infradead.org> Acked-by: Peter Zijlstra <peterz@infreadead.org> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Diffstat (limited to 'kernel')
-rw-r--r--kernel/trace/trace_selftest.c47
1 files changed, 30 insertions, 17 deletions
diff --git a/kernel/trace/trace_selftest.c b/kernel/trace/trace_selftest.c
index 5ef60499dc8e..593f52b73551 100644
--- a/kernel/trace/trace_selftest.c
+++ b/kernel/trace/trace_selftest.c
@@ -1025,6 +1025,12 @@ trace_selftest_startup_nop(struct tracer *trace, struct trace_array *tr)
#endif
#ifdef CONFIG_SCHED_TRACER
+
+struct wakeup_test_data {
+ struct completion is_ready;
+ int go;
+};
+
static int trace_wakeup_test_thread(void *data)
{
/* Make this a -deadline thread */
@@ -1034,51 +1040,56 @@ static int trace_wakeup_test_thread(void *data)
.sched_deadline = 10000000ULL,
.sched_period = 10000000ULL
};
- struct completion *x = data;
+ struct wakeup_test_data *x = data;
sched_setattr(current, &attr);
/* Make it know we have a new prio */
- complete(x);
+ complete(&x->is_ready);
/* now go to sleep and let the test wake us up */
set_current_state(TASK_INTERRUPTIBLE);
- schedule();
+ while (!x->go) {
+ schedule();
+ set_current_state(TASK_INTERRUPTIBLE);
+ }
- complete(x);
+ complete(&x->is_ready);
+
+ set_current_state(TASK_INTERRUPTIBLE);
/* we are awake, now wait to disappear */
while (!kthread_should_stop()) {
- /*
- * This will likely be the system top priority
- * task, do short sleeps to let others run.
- */
- msleep(100);
+ schedule();
+ set_current_state(TASK_INTERRUPTIBLE);
}
+ __set_current_state(TASK_RUNNING);
+
return 0;
}
-
int
trace_selftest_startup_wakeup(struct tracer *trace, struct trace_array *tr)
{
unsigned long save_max = tr->max_latency;
struct task_struct *p;
- struct completion is_ready;
+ struct wakeup_test_data data;
unsigned long count;
int ret;
- init_completion(&is_ready);
+ memset(&data, 0, sizeof(data));
+
+ init_completion(&data.is_ready);
/* create a -deadline thread */
- p = kthread_run(trace_wakeup_test_thread, &is_ready, "ftrace-test");
+ p = kthread_run(trace_wakeup_test_thread, &data, "ftrace-test");
if (IS_ERR(p)) {
printk(KERN_CONT "Failed to create ftrace wakeup test thread ");
return -1;
}
/* make sure the thread is running at -deadline policy */
- wait_for_completion(&is_ready);
+ wait_for_completion(&data.is_ready);
/* start the tracing */
ret = tracer_init(trace, tr);
@@ -1099,18 +1110,20 @@ trace_selftest_startup_wakeup(struct tracer *trace, struct trace_array *tr)
msleep(100);
}
- init_completion(&is_ready);
+ init_completion(&data.is_ready);
+
+ data.go = 1;
+ /* memory barrier is in the wake_up_process() */
wake_up_process(p);
/* Wait for the task to wake up */
- wait_for_completion(&is_ready);
+ wait_for_completion(&data.is_ready);
/* stop the tracing. */
tracing_stop();
/* check both trace buffers */
ret = trace_test_buffer(&tr->trace_buffer, NULL);
- printk("ret = %d\n", ret);
if (!ret)
ret = trace_test_buffer(&tr->max_buffer, &count);