From mboxrd@z Thu Jan 1 00:00:00 1970 From: Daniel Lezcano Subject: Re: [PATCH RESEND] smp: make wake up idle cpus more generic Date: Sat, 2 Apr 2016 15:10:40 +0200 Message-ID: <56FFC4D0.4090609@linaro.org> References: <1459489819-20435-1-git-send-email-lianwei.wang@gmail.com> <20160401070758.GA28352@gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: QUOTED-PRINTABLE Return-path: In-Reply-To: Sender: linux-kernel-owner@vger.kernel.org To: Lianwei Wang , Ingo Molnar Cc: rjw@rjwysocki.net, linux-pm@vger.kernel.org, linux-kernel@vger.kernel.org, kbuild-all@01.org, Peter Zijlstra , Thomas Gleixner List-Id: linux-pm@vger.kernel.org On 04/02/2016 08:15 AM, Lianwei Wang wrote: >> >> * Lianwei Wang wrote: >> >>> The wake_up_all_idle_cpus API always wake up all the online >>> cpus, but sometimes we only want to wake up a set of cpus. >>> Use a generic function to wake up a group of cpus that is >>> specified by the cpumask parameter. This generic API can >>> benefit to the cases that only need to wake up a set of >>> cpus. >> >> What is the new user of this new argument to the wake-up call? >> >> Thanks, >> >> Ingo > > The ARM big.LITTLE arch is one of the users to use the new wake up > call. Two clusters in these SoCs and each cluster has 2 or more CPUs. > For some cases, we only need to wake up the cpus on one cluster, not > all the cpus. The other cluster can keep in idle state to save power. > Another use case is that for the threads/irqs that bind to some cpus, > we also want to wake up the cpus that the threads/irqs bind to, and > the other cpus can stay in idle state. I'm updating the pm_qos code t= o > support binding the request to a set of cpus, and the > cpuidle_latency_notify call can pass the cpumask parameter to the new > wake-up call. Hi Lianwei, a quick suggestion : cpuidle_driver->cpumask -- Daniel --=20 Linaro.org =E2=94=82 Open source software fo= r ARM SoCs =46ollow Linaro: Facebook | Twitter | Blog