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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 <dbueso@suse.de>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Davidlohr Bueso 2015-02-13 14:39:08 -08:00 committed by Linus Torvalds
parent 0f3c5aab5e
commit 4d5755b147
1 changed files with 2 additions and 2 deletions
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4
fs/eventpoll.c
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@ -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 ? */