From mboxrd@z Thu Jan 1 00:00:00 1970 From: Daniel Lezcano Subject: Re: [PATCH 1/3] sched: Add new API wake_up_if_idle() to wake up the idle cpu Date: Thu, 04 Sep 2014 14:53:00 +0200 Message-ID: <540860AC.3030905@linaro.org> References: <1409815075-4180-1-git-send-email-chuansheng.liu@intel.com> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: QUOTED-PRINTABLE Return-path: Received: from mail-we0-f170.google.com ([74.125.82.170]:60293 "EHLO mail-we0-f170.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750962AbaIDMxG (ORCPT ); Thu, 4 Sep 2014 08:53:06 -0400 Received: by mail-we0-f170.google.com with SMTP id p10so10219511wes.29 for ; Thu, 04 Sep 2014 05:53:04 -0700 (PDT) In-Reply-To: <1409815075-4180-1-git-send-email-chuansheng.liu@intel.com> Sender: linux-pm-owner@vger.kernel.org List-Id: linux-pm@vger.kernel.org To: Chuansheng Liu , peterz@infradead.org, luto@amacapital.net, rjw@rjwysocki.net, mingo@redhat.com Cc: linux-pm@vger.kernel.org, linux-kernel@vger.kernel.org, changcheng.liu@intel.com, xiaoming.wang@intel.com, souvik.k.chakravarty@intel.com On 09/04/2014 09:17 AM, Chuansheng Liu wrote: > Implementing one new API wake_up_if_idle(), which is used to > wake up the idle CPU. > > Suggested-by: Andy Lutomirski > Signed-off-by: Chuansheng Liu Hi Chuanseng, in the future, please prefix the patches with the version number and a=20 changelog. Thanks -- Daniel Acked-by: Daniel Lezcano > --- > include/linux/sched.h | 1 + > kernel/sched/core.c | 19 +++++++++++++++++++ > 2 files changed, 20 insertions(+) > > diff --git a/include/linux/sched.h b/include/linux/sched.h > index 857ba40..3f89ac1 100644 > --- a/include/linux/sched.h > +++ b/include/linux/sched.h > @@ -1024,6 +1024,7 @@ struct sched_domain_topology_level { > extern struct sched_domain_topology_level *sched_domain_topology; > > extern void set_sched_topology(struct sched_domain_topology_level *= tl); > +extern void wake_up_if_idle(int cpu); > > #ifdef CONFIG_SCHED_DEBUG > # define SD_INIT_NAME(type) .name =3D #type > diff --git a/kernel/sched/core.c b/kernel/sched/core.c > index 1211575..b818548 100644 > --- a/kernel/sched/core.c > +++ b/kernel/sched/core.c > @@ -1620,6 +1620,25 @@ static void ttwu_queue_remote(struct task_stru= ct *p, int cpu) > } > } > > +void wake_up_if_idle(int cpu) > +{ > + struct rq *rq =3D cpu_rq(cpu); > + unsigned long flags; > + > + if (!is_idle_task(rq->curr)) > + return; > + > + if (set_nr_if_polling(rq->idle)) { > + trace_sched_wake_idle_without_ipi(cpu); > + } else { > + raw_spin_lock_irqsave(&rq->lock, flags); > + if (is_idle_task(rq->curr)) > + smp_send_reschedule(cpu); > + /* Else cpu is not in idle, do nothing here */ > + raw_spin_unlock_irqrestore(&rq->lock, flags); > + } > +} > + > bool cpus_share_cache(int this_cpu, int that_cpu) > { > return per_cpu(sd_llc_id, this_cpu) =3D=3D per_cpu(sd_llc_id, that= _cpu); > --=20 Linaro.org =E2=94=82 Open source software fo= r ARM SoCs =46ollow Linaro: Facebook | Twitter | Blog