From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751451AbeDDIuH (ORCPT ); Wed, 4 Apr 2018 04:50:07 -0400 Received: from mail-wm0-f45.google.com ([74.125.82.45]:53031 "EHLO mail-wm0-f45.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751284AbeDDIuF (ORCPT ); Wed, 4 Apr 2018 04:50:05 -0400 X-Google-Smtp-Source: AIpwx48xYAy6fhXOlSwQx8L10JEJkpgvPI7HnpV50nPBeqbuWQIwMb6Jdgr4q2rfCz0hOtKDY7TCmw== Subject: Re: [PATCH V2 6/7] thermal/drivers/cpu_cooling: Introduce the cpu idle cooling driver To: Viresh Kumar Cc: edubezval@gmail.com, kevin.wangtao@linaro.org, leo.yan@linaro.org, vincent.guittot@linaro.org, amit.kachhap@gmail.com, linux-kernel@vger.kernel.org, javi.merino@kernel.org, rui.zhang@intel.com, daniel.thompson@linaro.org, linux-pm@vger.kernel.org References: <1519226968-19821-1-git-send-email-daniel.lezcano@linaro.org> <1519226968-19821-7-git-send-email-daniel.lezcano@linaro.org> <20180223073432.GF26947@vireshk-i7> <20180226043021.GK26947@vireshk-i7> From: Daniel Lezcano Message-ID: <78504a65-d21a-eea0-d8af-6e12d5747b87@linaro.org> Date: Wed, 4 Apr 2018 10:50:02 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.6.0 MIME-Version: 1.0 In-Reply-To: <20180226043021.GK26947@vireshk-i7> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 26/02/2018 05:30, Viresh Kumar wrote: [ ... ] >>>> + >>>> + for_each_possible_cpu(cpu) { >>>> + cpumask = topology_core_cpumask(cpu); >>>> + >>>> + cct = per_cpu_ptr(&cpuidle_cooling_tsk, cpu); >>>> + >>>> + /* >>>> + * This condition makes the first cpu belonging to the >>>> + * cluster to create a cooling device and allocates >>>> + * the structure. Others CPUs belonging to the same >>>> + * cluster will just increment the refcount on the >>>> + * cooling device structure and initialize it. >>>> + */ >>>> + if (cpu == cpumask_first(cpumask)) { >>> >>> Your function still have few assumptions of cpu numbering and it will >>> break in few cases. What if the CPUs on a big Little system (4x4) are >>> present in this order: B L L L L B B B ?? >>> >>> This configuration can happen if CPUs in DT are marked as: 0-3 LITTLE, >>> 4-7 big and a big CPU is used by the boot loader to bring up Linux. >> >> Ok, how can I sort it out ? > > I would do something like this: > > cpumask_copy(possible, cpu_possible_mask); > > while (!cpumask_empty(possible)) { > first = cpumask_first(possible); > cpumask = topology_core_cpumask(first); > cpumask_andnot(possible, possible, cpumask); > > allocate_cooling_dev(first); //This is most of this function in your patch. > > while (!cpumask_empty(cpumask)) { > temp = cpumask_first(possible); > //rest init "temp" > cpumask_clear_cpu(temp, cpumask); > } > > //Everything done, register cooling device for cpumask. > } Mmh, that sounds very complex. May be it is simpler to count the number of cluster and initialize the idle_cdev for each cluster and then go for this loop with the cluster cpumask. -- Linaro.org │ Open source software for ARM SoCs Follow Linaro: Facebook | Twitter | Blog