On Tue, 2011-04-12 at 19:23 -0700, Linus Torvalds wrote: > kernel/sched.c | 20 ++++++++++---------- > 1 files changed, 10 insertions(+), 10 deletions(-) > > diff --git a/kernel/sched.c b/kernel/sched.c > index 48013633d792..a187c3fe027b 100644 > --- a/kernel/sched.c > +++ b/kernel/sched.c > @@ -4111,20 +4111,20 @@ need_resched: > try_to_wake_up_local(to_wakeup); > } > 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; > } > > - /* > - * 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); > > if (unlikely(!rq->nr_running)) Right, that cures the preemption problem. The reason I suggested placing it where it was is that I'd like to keep all things that release rq->lock in the middle of schedule() in one place, but I guess we can cure that with some extra comments. -- dm-devel mailing list dm-devel@xxxxxxxxxx https://www.redhat.com/mailman/listinfo/dm-devel