Messages in this thread | | | Date | Fri, 24 Oct 2014 07:04:56 +0800 | From | Wanpeng Li <> | Subject | Re: [PATCH v2 2/3] sched/dl: Cleanup prio_changed_dl() |
| |
10/22/14, 12:24 AM, Juri Lelli: > Hi Kirill, > > On 02/10/14 10:52, Kirill Tkhai wrote: >> В Чт, 02/10/2014 в 11:36 +0200, Peter Zijlstra пишет: >>> On Wed, Oct 01, 2014 at 01:04:35AM +0400, Kirill Tkhai wrote: >>>> From: Kirill Tkhai <ktkhai@parallels.com> >>>> >>>> rq->curr task can't be in "dequeued" state in prio_changed_dl(). >>>> (The only place we can have that is __schedule()). So, we delete >>>> rq->curr check. >>> the CBS timer can throttle it right? >> Yeah, it's better to check for on_dl_rq(): >> >> [PATCH]sched/dl: Cleanup prio_changed_dl() >> >> rq->curr task can't be in "dequeued" state in prio_changed_dl(). >> (The only place we can have that is __schedule()). So, we delete >> rq->curr check. >> >> We shouldn't do balancing if deadline task is throttled too. >> >> Also delete "else" branch which is dead code (switched_to_dl() >> is not interested in dequeued tasks and we are not interested >> in balancing in this case). >> > So, I agree that calling switched_to_dl() makes little sense, > but don't we have to deal with updates to not running tasks as > in rt.c? Something like this maybe? > > From 75ee75a5fd76526baaed3ba8a58f3ff7daa89cd6 Mon Sep 17 00:00:00 2001 > From: Juri Lelli <juri.lelli@arm.com> > Date: Tue, 21 Oct 2014 17:15:15 +0100 > Subject: [PATCH] sched/deadline: cleanup prio_changed_dl() > > --- > kernel/sched/deadline.c | 16 +++++++++++++--- > 1 file changed, 13 insertions(+), 3 deletions(-) > > diff --git a/kernel/sched/deadline.c b/kernel/sched/deadline.c > index 28d6088..1e62e31 100644 > --- a/kernel/sched/deadline.c > +++ b/kernel/sched/deadline.c > @@ -1661,7 +1661,10 @@ static void switched_to_dl(struct rq *rq, struct task_struct *p) > static void prio_changed_dl(struct rq *rq, struct task_struct *p, > int oldprio) > { > - if (task_on_rq_queued(p) || rq->curr == p) { > + if (!on_dl_rq(&p->dl))
I'm not sure if this should be task_on_rq_queued() check. All check_class_changed() callsites dequeue entity if task_on_rq_queued() is true which leads to on_dl_rq(&p->dl) always return false.
Regards, Wanpeng Li
> + return; > + > + if (rq->curr == p) { > #ifdef CONFIG_SMP > /* > * This might be too much, but unfortunately > @@ -1688,8 +1691,15 @@ static void prio_changed_dl(struct rq *rq, struct task_struct *p, > */ > resched_curr(rq); > #endif /* CONFIG_SMP */ > - } else > - switched_to_dl(rq, p); > + } else { > + /* > + * This task is not running, so if its deadline is > + * now more imminent than that of the current running > + * task then reschedule. > + */ > + if (dl_time_before(p->dl.deadline, rq->curr->dl.deadline)) > + resched_curr(rq); > + } > } > > const struct sched_class dl_sched_class = {
-- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
| |