linux-kernel - Re: [RFC,v2 3/3] sched: ignore task_h_load for CPU_NEWLY

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Date:   Thu, 9 Feb 2017 11:12:20 +0100
From:   Uladzislau Rezki <urezki@...il.com>
To:     Mike Galbraith <efault@....de>
Cc:     Ingo Molnar <mingo@...hat.com>,
        LKML <linux-kernel@...r.kernel.org>,
        Peter Zijlstra <peterz@...radead.org>,
        Uladzislau 2 Rezki <uladzislau2.rezki@...ymobile.com>
Subject: Re: [RFC,v2 3/3] sched: ignore task_h_load for CPU_NEWLY_IDLE

>
> On Wed, 2017-02-08 at 09:43 +0100, Uladzislau Rezki wrote:
> > From: Uladzislau 2 Rezki <uladzislau2.rezki@...ymobile.com>
> >
> > A load balancer calculates imbalance factor for particular shed
>                                                              ^sched
Will fix that.

> > domain and tries to steal up the prescribed amount of weighted load.
> > However, a small imbalance factor would sometimes prevent us from
> > stealing any tasks at all. When a CPU is newly idle, it should
> > steal first task which passes a migration criteria.
>                          s/passes a/meets the
Will change the description.

> >
> > Signed-off-by: Uladzislau 2 Rezki <uladzislau2.rezki@...ymobile.com>
> > ---
> >  kernel/sched/fair.c | 13 +++++++++++--
> >  1 file changed, 11 insertions(+), 2 deletions(-)
> >
> > diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
> > index 232ef3c..29e0d7f 100644
> > --- a/kernel/sched/fair.c
> > +++ b/kernel/sched/fair.c
> >       >       > env->loop++;
> > @@ -6824,8 +6832,9 @@ static int detach_tasks(struct lb_env *env)
> >  >    >       > if (sched_feat(LB_MIN) && load < 16 && !env->sd->nr_balance_failed)
> >  >    >       >       > goto next;
> >
> > ->    >       > if ((load / 2) > env->imbalance)
> > ->    >       >       > goto next;
> > +>    >       > if (env->idle != CPU_NEWLY_IDLE)
> > +>    >       >       > if ((load / 2) > env->imbalance)
> > +>    >       >       >       > goto next;
>
> Those two ifs could be one ala if (foo && bar).
Agree.

--
Uladzislau Rezki