[PATCH 1/3] workqueue: optimize mod_delayed_work_on() when @delay == 0

[Joonsoo Kim]

After try_to_grab_pending(), __queue_delayed_work() is invoked
in mod_delayed_work_on(). When @delay == 0, we can call __queue_work()
directly in order to avoid setting useless timer.

Signed-off-by: Joonsoo Kim <js1304@xxxxxxxxx>

diff --git a/kernel/workqueue.c b/kernel/workqueue.c
index d951daa..c57358e 100644
--- a/kernel/workqueue.c
+++ b/kernel/workqueue.c
@@ -1477,7 +1477,11 @@ bool mod_delayed_work_on(int cpu, struct workqueue_struct *wq,
 	} while (unlikely(ret == -EAGAIN));
 
 	if (likely(ret >= 0)) {
-		__queue_delayed_work(cpu, wq, dwork, delay);
+		if (!delay)
+			__queue_work(cpu, wq, &dwork->work);
+		else
+			__queue_delayed_work(cpu, wq, dwork, delay);
+
 		local_irq_restore(flags);
 	}
 
-- 
1.7.9.5

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