| Message ID | BANLkTikBEJa7bJJoLFU7NoiEgOjVHVG08A@mail.gmail.com (mailing list archive) |
|---|---|
| State | Not Applicable, archived |
| Headers | show |
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@redhat.com https://www.redhat.com/mailman/listinfo/dm-devel
On 2011-04-13 13:12, Peter Zijlstra wrote: > 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. We definitely only want to do it on going to sleep, not preempt events. So if you are fine with this change, then lets please do that. Linus, I've got a few other things queued up in the area, I'll add this and send them off soon. Or feel free to add this one yourself, since you already did it.
On Wed, 2011-04-13 at 13:23 +0200, Jens Axboe wrote: > We definitely only want to do it on going to sleep, not preempt events. > So if you are fine with this change, then lets please do that. Here's the Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl>, that goes with it ;-) > Linus, I've got a few other things queued up in the area, I'll add this > and send them off soon. Or feel free to add this one yourself, since you > already did it. Right, please send it onwards or have Linus commit it himself and I'll cook up a patch clarifying the rq->lock'ing mess around there. -- dm-devel mailing list dm-devel@redhat.com https://www.redhat.com/mailman/listinfo/dm-devel
On Wed, Apr 13, 2011 at 4:23 AM, Jens Axboe <jaxboe@fusionio.com> wrote: > > Linus, I've got a few other things queued up in the area, I'll add this > and send them off soon. Or feel free to add this one yourself, since you > already did it. Ok, I committed it with Peter's and your acks. And if you already put it in your git tree too, git will merge it. Linus -- dm-devel mailing list dm-devel@redhat.com https://www.redhat.com/mailman/listinfo/dm-devel
On 2011-04-13 17:13, Linus Torvalds wrote: > On Wed, Apr 13, 2011 at 4:23 AM, Jens Axboe <jaxboe@fusionio.com> wrote: >> >> Linus, I've got a few other things queued up in the area, I'll add this >> and send them off soon. Or feel free to add this one yourself, since you >> already did it. > > Ok, I committed it with Peter's and your acks. Great, thanks. > And if you already put it in your git tree too, git will merge it. I did not, I had a feeling you'd merge this one.
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))