From mboxrd@z Thu Jan  1 00:00:00 1970
Return-Path: <linux-kernel-owner@vger.kernel.org>
Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand
        id S1751090AbdHRHzl (ORCPT <rfc822;w@1wt.eu>);
        Fri, 18 Aug 2017 03:55:41 -0400
Received: from LGEAMRELO11.lge.com ([156.147.23.51]:39187 "EHLO
        lgeamrelo11.lge.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org
        with ESMTP id S1750926AbdHRHzk (ORCPT
        <rfc822;linux-kernel@vger.kernel.org>);
        Fri, 18 Aug 2017 03:55:40 -0400
X-Original-SENDERIP: 156.147.1.121
X-Original-MAILFROM: byungchul.park@lge.com
X-Original-SENDERIP: 10.177.222.33
X-Original-MAILFROM: byungchul.park@lge.com
Date: Fri, 18 Aug 2017 16:55:33 +0900
From: Byungchul Park <byungchul.park@lge.com>
To: "Joel Fernandes (Google)" <joel.opensrc@gmail.com>
Cc: Peter Zijlstra <peterz@infradead.org>, mingo@kernel.org,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
        juri.lelli@gmail.com, rostedt@goodmis.org, kernel-team@lge.com,
        Joel Fernandes <joelaf@google.com>
Subject: Re: [PATCH v7 1/2] sched/deadline: Add support for SD_PREFER_SIBLING
 on find_later_rq()
Message-ID: <20170818075533.GC20323@X58A-UD3R>
References: <1503036313-15044-1-git-send-email-byungchul.park@lge.com>
 <1503036313-15044-2-git-send-email-byungchul.park@lge.com>
 <CAEi0qNkH1W9+d3tYwZsY-cboaws9zu1E_EvmJNGA=ScRwprm0Q@mail.gmail.com>
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <CAEi0qNkH1W9+d3tYwZsY-cboaws9zu1E_EvmJNGA=ScRwprm0Q@mail.gmail.com>
User-Agent: Mutt/1.5.21 (2010-09-15)
Sender: linux-kernel-owner@vger.kernel.org
List-ID: <linux-kernel.vger.kernel.org>
X-Mailing-List: linux-kernel@vger.kernel.org

On Fri, Aug 18, 2017 at 12:21:46AM -0700, Joel Fernandes (Google) wrote:
> Hi Byungchul,
> 
> On Thu, Aug 17, 2017 at 11:05 PM, Byungchul Park <byungchul.park@lge.com> wrote:
> > It would be better to avoid pushing tasks to other cpu within
> > a SD_PREFER_SIBLING domain, instead, get more chances to check other
> > siblings.
> >
> > Signed-off-by: Byungchul Park <byungchul.park@lge.com>
> > ---
> >  kernel/sched/deadline.c | 55 ++++++++++++++++++++++++++++++++++++++++++++++---
> >  1 file changed, 52 insertions(+), 3 deletions(-)
> >
> > diff --git a/kernel/sched/deadline.c b/kernel/sched/deadline.c
> > index 0223694..8f69a37 100644
> > --- a/kernel/sched/deadline.c
> > +++ b/kernel/sched/deadline.c
> > @@ -1319,12 +1319,35 @@ static struct task_struct *pick_earliest_pushable_dl_task(struct rq *rq, int cpu
> >
> >  static DEFINE_PER_CPU(cpumask_var_t, local_cpu_mask_dl);
> >
> > +/*
> > + * Find the first cpu in: mask & sd & ~prefer
> > + */
> > +static int find_cpu(const struct cpumask *mask,
> > +                   const struct sched_domain *sd,
> > +                   const struct sched_domain *prefer)
> > +{
> > +       const struct cpumask *sds = sched_domain_span(sd);
> > +       const struct cpumask *ps  = prefer ? sched_domain_span(prefer) : NULL;
> > +       int cpu = -1;
> > +
> > +       while ((cpu = cpumask_next(cpu, mask)) < nr_cpu_ids) {
> 
> This can be simplified to for_each_cpu(cpu, mask) ?

Indeed, exactly.

I will use that, thank you.