From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id F079CCD5497 for ; Tue, 19 Sep 2023 07:50:01 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230513AbjISHuF (ORCPT ); Tue, 19 Sep 2023 03:50:05 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:58388 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229699AbjISHuD (ORCPT ); Tue, 19 Sep 2023 03:50:03 -0400 Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by lindbergh.monkeyblade.net (Postfix) with ESMTP id 66921FC; Tue, 19 Sep 2023 00:49:57 -0700 (PDT) Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 448081FB; Tue, 19 Sep 2023 00:50:34 -0700 (PDT) Received: from [10.57.92.124] (unknown [10.57.92.124]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 47D083F59C; Tue, 19 Sep 2023 00:49:55 -0700 (PDT) Message-ID: Date: Tue, 19 Sep 2023 09:49:45 +0200 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:102.0) Gecko/20100101 Thunderbird/102.15.0 Subject: Re: [PATCH] cpufreq: Rebuild sched-domains when removing cpufreq driver Content-Language: en-US To: Dietmar Eggemann , linux-kernel@vger.kernel.org Cc: Shrikanth Hegde , vschneid@redhat.com, "Rafael J. Wysocki" , Viresh Kumar , linux-pm@vger.kernel.org References: <20230918112937.493352-1-pierre.gondois@arm.com> From: Pierre Gondois In-Reply-To: Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 9/19/23 01:03, Dietmar Eggemann wrote: > On 18/09/2023 13:29, Pierre Gondois wrote: >> The Energy Aware Scheduler (EAS) relies on the schedutil governor. >> When moving to/from the schedutil governor, sched domains must be >> rebuilt to allow re-evaluating the enablement conditions of EAS. >> This is done through sched_cpufreq_governor_change(). >> >> Having a cpufreq governor assumes having a cpufreq driver running. >> Inserting/removing a cpufreq driver should trigger a re-evaluation >> of EAS enablement conditions, avoiding to see EAS enabled when >> removing a running cpufreq driver. >> >> Add a sched_cpufreq_governor_change() call in cpufreq driver removal >> path. > > Rebuilding SDs when inserting the driver is already covered by > > cpufreq_online() > cpufreq_set_policy() > sched_cpufreq_governor_change() > if (old or new gov eq. schedutil) > schedule_work(&rebuild_sd_work) > > So what's missing is only a sched_cpufreq_governor_change() call when > removing the driver, right? Yes exact, removing a cpufreq driver (e.g. `rmmod cppc_cpufreq.ko`) goes through: cpufreq_remove_dev() \-__cpufreq_offline() so the path you mentioned is not used in this case. Regards, Pierre