workqueue: remove redundant function invocation

timer_stats_timer_set_start_info is invoked twice, additionally, the
invocation of this function can be moved to where it is only called when a
delay is really required.

Signed-off-by: Andrew Liu <shengping.liu@windriver.com>
Cc: Pavel Machek <pavel@ucw.cz>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Oleg Nesterov <oleg@tv-sign.ru>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

kernel/workqueue.c

@@ -195,7 +195,6 @@ static void delayed_work_timer_fn(unsigned long __data)
 int queue_delayed_work(struct workqueue_struct *wq,
 			struct delayed_work *dwork, unsigned long delay)
 {
-	timer_stats_timer_set_start_info(&dwork->timer);
 	if (delay == 0)
 		return queue_work(wq, &dwork->work);
 
@@ -219,11 +218,12 @@ int queue_delayed_work_on(int cpu, struct workqueue_struct *wq,
 	struct timer_list *timer = &dwork->timer;
 	struct work_struct *work = &dwork->work;
 
-	timer_stats_timer_set_start_info(&dwork->timer);
 	if (!test_and_set_bit(WORK_STRUCT_PENDING, work_data_bits(work))) {
 		BUG_ON(timer_pending(timer));
 		BUG_ON(!list_empty(&work->entry));
 
+		timer_stats_timer_set_start_info(&dwork->timer);
+
 		/* This stores cwq for the moment, for the timer_fn */
 		set_wq_data(work, wq_per_cpu(wq, raw_smp_processor_id()));
 		timer->expires = jiffies + delay;
@@ -564,7 +564,6 @@ EXPORT_SYMBOL(schedule_work);
 int schedule_delayed_work(struct delayed_work *dwork,
 					unsigned long delay)
 {
-	timer_stats_timer_set_start_info(&dwork->timer);
 	return queue_delayed_work(keventd_wq, dwork, delay);
 }
 EXPORT_SYMBOL(schedule_delayed_work);
@@ -581,7 +580,6 @@ EXPORT_SYMBOL(schedule_delayed_work);
 int schedule_delayed_work_on(int cpu,
 			struct delayed_work *dwork, unsigned long delay)
 {
-	timer_stats_timer_set_start_info(&dwork->timer);
 	return queue_delayed_work_on(cpu, keventd_wq, dwork, delay);
 }
 EXPORT_SYMBOL(schedule_delayed_work_on);