Re: [PATCH v10 8/9] sched/fair: Add latency list

[Vincent Guittot]

On Tue, 21 Feb 2023 at 16:12, Peter Zijlstra <peterz@xxxxxxxxxxxxx> wrote:
>
> On Fri, Jan 13, 2023 at 03:12:33PM +0100, Vincent Guittot wrote:
> > @@ -12552,8 +12634,15 @@ int sched_group_set_latency(struct task_group *tg, s64 latency)
> >
> >       for_each_possible_cpu(i) {
> >               struct sched_entity *se = tg->se[i];
> > +             struct rq *rq = cpu_rq(i);
> > +             struct rq_flags rf;
> > +
> > +             rq_lock_irqsave(rq, &rf);
> >
> > +             __dequeue_latency(se->cfs_rq, se);
> >               WRITE_ONCE(se->latency_offset, latency);
> > +
> > +             rq_unlock_irqrestore(rq, &rf);
> >       }
>
> This seems asymmetric; maybe something like:
>
>         queued = __dequeue_latency(..);
>         WRITE_ONCE(...);
>         if (queued)
>                 __enqueue_latency(...);
>
> ?

Fair enough