On Thu, 24 Sep 2015 16:44:18 +0200
Frederic Weisbecker <fweis...@gmail.com> wrote:
> On Thu, Sep 10, 2015 at 03:58:27PM -0400, Luiz Capitulino wrote:
> > tick_nohz_full_kick_cpu() performs the same check.
> >
> > Signed-off-by: Luiz Capitulino <lcapitul...@redhat.com>
> > ---
> > kernel/sched/sched.h | 20 +++++++++-----------
> > 1 file changed, 9 insertions(+), 11 deletions(-)
> >
> > diff --git a/kernel/sched/sched.h b/kernel/sched/sched.h
> > index 68cda11..102eb18 100644
> > --- a/kernel/sched/sched.h
> > +++ b/kernel/sched/sched.h
> > @@ -1323,17 +1323,15 @@ static inline void add_nr_running(struct rq *rq,
> > unsigned count)
> > #endif
> >
> > #ifdef CONFIG_NO_HZ_FULL
> > - if (tick_nohz_full_cpu(rq->cpu)) {
> > - /*
> > - * Tick is needed if more than one task runs on a CPU.
> > - * Send the target an IPI to kick it out of nohz mode.
> > - *
> > - * We assume that IPI implies full memory barrier and
> > the
> > - * new value of rq->nr_running is visible on reception
> > - * from the target.
> > - */
> > - tick_nohz_full_kick_cpu(rq->cpu);
> > - }
> > + /*
> > + * Tick is needed if more than one task runs on a CPU.
> > + * Send the target an IPI to kick it out of nohz mode.
> > + *
> > + * We assume that IPI implies full memory barrier and the
> > + * new value of rq->nr_running is visible on reception
> > + * from the target.
> > + */
> > + tick_nohz_full_kick_cpu(rq->cpu);
>
> Nope, we want to keep this because tick_nohz_full_cpu() does a static key
> check.
> Most users don't care about nohz_full and I really want to keep nohz full off
> case
> overhead to the bare minimum.
Makes sense.
>
> Thanks.
>
> > #endif
> > }
> > }
> > --
> > 2.1.0
> >
>
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