Messages in this thread | | | Subject | Re: [PATCH 06/16] sched: SCHED_DEADLINE push and pull logic | From | Steven Rostedt <> | Date | Tue, 24 Apr 2012 14:50:56 -0400 |
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On Tue, 2012-04-24 at 15:15 +0200, Peter Zijlstra wrote: > On Wed, 2012-04-11 at 12:33 -0400, Steven Rostedt wrote: > > On Fri, 2012-04-06 at 09:14 +0200, Juri Lelli wrote: > > > > > > @@ -543,6 +897,9 @@ static void put_prev_task_dl(struct rq *rq, struct task_struct *p) > > > { > > > update_curr_dl(rq); > > > p->se.exec_start = 0; > > > + > > > + if (on_dl_rq(&p->dl) && p->dl.nr_cpus_allowed > 1) > > > + enqueue_pushable_dl_task(rq, p); > > > } > > > > Ouch! We need to fix this. This has nothing to do with your patch > > series, but if you look at schedule(): > > > > put_prev_task(rq, prev); > > next = pick_next_task(rq); > > > > > > We put the prev task and then pick the next task. If we call schedule > > for some reason when we don't need to really schedule, then we just > > added and removed from the pushable rb tree the same task. That is, we > > did the rb manipulation twice, for no good reason. > > > > Not sure how to fix this. But it will require a generic change. > > > Something like so: https://lkml.org/lkml/2012/2/16/487 ?
But it still does the same thing:
+static struct task_struct * +pick_next_task_rt(struct rq *rq, struct task_struct *prev) { - struct task_struct *p = _pick_next_task_rt(rq); + struct task_struct *p; + struct rt_rq *rt_rq = &rq->rt; + + if (!rt_rq->rt_nr_running) + return NULL; + + if (rt_rq_throttled(rt_rq)) + return NULL; + + if (prev) + prev->sched_class->put_prev_task(rq, prev); + + p = _pick_next_task_rt(rq);
Now if we can do the _pick_next_task_rt() before put_prev_task(), and only do the put_prev_task() if p != prev, then that would be something. -- Steve
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