Re: [PATCH 07/10] sched: Migrate sched to use new tick dependency mask model

From: Frederic Weisbecker
Date: Wed Jul 29 2015 - 09:01:56 EST


On Fri, Jul 24, 2015 at 12:56:42PM -0400, Chris Metcalf wrote:
> On 07/23/2015 12:42 PM, Frederic Weisbecker wrote:
> >+static inline void sched_update_tick_dependency(struct rq *rq)
> >+{
> >+ int cpu;
> >+
> >+ if (!tick_nohz_full_enabled())
> >+ return;
> >+
> >+ cpu = cpu_of(rq);
> >+
> >+ if (!tick_nohz_full_cpu(rq->cpu))
> >+ return;
> >+
> >+ if (sched_can_stop_tick(rq))
> >+ tick_nohz_clear_tick_dependency_cpu(TICK_SCHED_BIT, cpu);
> >+ else
> >+ tick_nohz_set_tick_dependency_cpu(TICK_SCHED_BIT, cpu);
> >+}
>
> Is it worth asserting that the rq is locked at this point? Presumably that's
> a requirement so that the cpu can't change out from under you.

Indeed it has become a requirement here. I'll add a check.

Thanks.
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