epoll: optimize setting task running after blocking

After waking up a task waiting for an event, we explicitly mark it as TASK_RUNNING (which is necessary as we do the checks for wakeups as TASK_INTERRUPTIBLE). Once running and dealing with actually delivering the events, we're obviously not planning on calling schedule, thus we can relax the implied barrier and simply update the state with __set_current_state(). Signed-off-by: Davidlohr Bueso <[email protected]> Cc: Alexander Viro <[email protected]> Signed-off-by: Andrew Morton <[email protected]> Signed-off-by: Linus Torvalds <[email protected]>
kyagi · Feb 14, 2015 · 4d5755b · 4d5755b
1 parent 0f3c5aa
commit 4d5755b
Showing 1 changed file with 2 additions and 2 deletions.
diff --git a/fs/eventpoll.c b/fs/eventpoll.c
@@ -1639,9 +1639,9 @@ static int ep_poll(struct eventpoll *ep, struct epoll_event __user *events,
 
 			spin_lock_irqsave(&ep->lock, flags);
 		}
-		__remove_wait_queue(&ep->wq, &wait);
 
-		set_current_state(TASK_RUNNING);
+		__remove_wait_queue(&ep->wq, &wait);
+		__set_current_state(TASK_RUNNING);
 	}
 check_events:
 	/* Is it worth to try to dig for events ? */