Commit 6631e635 authored by Linus Torvalds's avatar Linus Torvalds

block: don't flush plugged IO on forced preemtion scheduling

We really only want to unplug the pending IO when the process actually
goes to sleep.  So move the test for flushing the plug up to the place
where we actually deactivate the task - where we have properly checked
for preemption and for the process really sleeping.
Acked-by: default avatarJens Axboe <jaxboe@fusionio.com>
Acked-by: default avatarPeter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent a626ca6a
...@@ -4111,20 +4111,20 @@ asmlinkage void __sched schedule(void) ...@@ -4111,20 +4111,20 @@ asmlinkage void __sched schedule(void)
try_to_wake_up_local(to_wakeup); try_to_wake_up_local(to_wakeup);
} }
deactivate_task(rq, prev, DEQUEUE_SLEEP); deactivate_task(rq, prev, DEQUEUE_SLEEP);
/*
* If we are going to sleep and we have plugged IO queued, make
* sure to submit it to avoid deadlocks.
*/
if (blk_needs_flush_plug(prev)) {
raw_spin_unlock(&rq->lock);
blk_flush_plug(prev);
raw_spin_lock(&rq->lock);
}
} }
switch_count = &prev->nvcsw; switch_count = &prev->nvcsw;
} }
/*
* If we are going to sleep and we have plugged IO queued, make
* sure to submit it to avoid deadlocks.
*/
if (prev->state != TASK_RUNNING && blk_needs_flush_plug(prev)) {
raw_spin_unlock(&rq->lock);
blk_flush_plug(prev);
raw_spin_lock(&rq->lock);
}
pre_schedule(rq, prev); pre_schedule(rq, prev);
if (unlikely(!rq->nr_running)) if (unlikely(!rq->nr_running))
......
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