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, 21 Aug 2014 03:54:18 +0200 Message-ID: <53F5514A.5050007@linaro.org> References: <1408351052-25075-1-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: In-Reply-To: <1408351052-25075-1-git-send-email-chuansheng.liu@intel.com> Sender: linux-kernel-owner@vger.kernel.org To: Chuansheng Liu , luto@amacapital.net, peterz@infradead.org, 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 List-Id: linux-pm@vger.kernel.org On 08/18/2014 10:37 AM, Chuansheng Liu wrote: > Implementing one new API wake_up_if_idle(), which is used to > wake up the idle CPU. Is this patchset tested ? Did you check it solves the issue you were=20 facing ? > Suggested-by: Andy Lutomirski > Signed-off-by: Chuansheng Liu > --- > include/linux/sched.h | 1 + > kernel/sched/core.c | 16 ++++++++++++++++ > 2 files changed, 17 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..adf104f 100644 > --- a/kernel/sched/core.c > +++ b/kernel/sched/core.c > @@ -1620,6 +1620,22 @@ 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 (set_nr_if_polling(rq->idle)) { > + trace_sched_wake_idle_without_ipi(cpu); > + } else { > + raw_spin_lock_irqsave(&rq->lock, flags); > + if (rq->curr =3D=3D rq->idle) > + 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