Messages in this thread Patch in this message |  | | Date | Tue, 21 Oct 2014 17:24:01 +0100 | From | Juri Lelli <> | Subject | Re: [PATCH v2 2/3] sched/dl: Cleanup prio_changed_dl() |
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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)) + 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 = { -- 2.1.0 Thanks,
- Juri
> Signed-off-by: Kirill Tkhai <ktkhai@parallels.com> > > diff --git a/kernel/sched/deadline.c b/kernel/sched/deadline.c > index 63f8b4a..ccea917 100644 > --- a/kernel/sched/deadline.c > +++ b/kernel/sched/deadline.c > @@ -1638,35 +1638,33 @@ 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)) > + return; > #ifdef CONFIG_SMP > - /* > - * This might be too much, but unfortunately > - * we don't have the old deadline value, and > - * we can't argue if the task is increasing > - * or lowering its prio, so... > - */ > - if (!rq->dl.overloaded) > - pull_dl_task(rq); > - > - /* > - * If we now have a earlier deadline task than p, > - * then reschedule, provided p is still on this > - * runqueue. > - */ > - if (dl_time_before(rq->dl.earliest_dl.curr, p->dl.deadline) && > - rq->curr == p) > - resched_curr(rq); > -#else > - /* > - * Again, we don't know if p has a earlier > - * or later deadline, so let's blindly set a > - * (maybe not needed) rescheduling point. > - */ > + /* > + * This might be too much, but unfortunately > + * we don't have the old deadline value, and > + * we can't argue if the task is increasing > + * or lowering its prio, so... > + */ > + if (!rq->dl.overloaded) > + pull_dl_task(rq); > + /* > + * If we now have a earlier deadline task than p, > + * then reschedule, provided p is still on this > + * runqueue. > + */ > + if (dl_time_before(rq->dl.earliest_dl.curr, p->dl.deadline) && > + rq->curr == p) > resched_curr(rq); > +#else > + /* > + * Again, we don't know if p has a earlier > + * or later deadline, so let's blindly set a > + * (maybe not needed) rescheduling point. > + */ > + resched_curr(rq); > #endif /* CONFIG_SMP */ > - } else > - switched_to_dl(rq, p); > } > > const struct sched_class dl_sched_class = { > > >
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