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 X-Spam-Level: X-Spam-Status: No, score=-5.3 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 46E71C433E3 for ; Tue, 2 Jun 2020 11:31:45 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 300A92068D for ; Tue, 2 Jun 2020 11:31:45 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726580AbgFBLbj (ORCPT ); Tue, 2 Jun 2020 07:31:39 -0400 Received: from foss.arm.com ([217.140.110.172]:49630 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725900AbgFBLbi (ORCPT ); Tue, 2 Jun 2020 07:31:38 -0400 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 B08A931B; Tue, 2 Jun 2020 04:31:37 -0700 (PDT) Received: from [10.37.12.87] (unknown [10.37.12.87]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 54B5E3F52E; Tue, 2 Jun 2020 04:31:27 -0700 (PDT) Subject: Re: [PATCH v8 4/8] PM / EM: add support for other devices than CPUs in Energy Model To: Daniel Lezcano , linux-kernel@vger.kernel.org, linux-pm@vger.kernel.org, linux-arm-kernel@lists.infradead.org, dri-devel@lists.freedesktop.org, linux-omap@vger.kernel.org, linux-mediatek@lists.infradead.org, linux-arm-msm@vger.kernel.org, linux-imx@nxp.com Cc: Dietmar.Eggemann@arm.com, cw00.choi@samsung.com, b.zolnierkie@samsung.com, rjw@rjwysocki.net, sudeep.holla@arm.com, viresh.kumar@linaro.org, nm@ti.com, sboyd@kernel.org, rui.zhang@intel.com, amit.kucheria@verdurent.com, mingo@redhat.com, peterz@infradead.org, juri.lelli@redhat.com, vincent.guittot@linaro.org, rostedt@goodmis.org, qperret@google.com, bsegall@google.com, mgorman@suse.de, shawnguo@kernel.org, s.hauer@pengutronix.de, festevam@gmail.com, kernel@pengutronix.de, khilman@kernel.org, agross@kernel.org, bjorn.andersson@linaro.org, robh@kernel.org, matthias.bgg@gmail.com, steven.price@arm.com, tomeu.vizoso@collabora.com, alyssa.rosenzweig@collabora.com, airlied@linux.ie, daniel@ffwll.ch, liviu.dudau@arm.com, lorenzo.pieralisi@arm.com, patrick.bellasi@matbug.net, orjan.eide@arm.com, rdunlap@infradead.org, mka@chromium.org References: <20200527095854.21714-1-lukasz.luba@arm.com> <20200527095854.21714-5-lukasz.luba@arm.com> From: Lukasz Luba Message-ID: <7201e161-6952-6e28-4036-bd0f0353ec30@arm.com> Date: Tue, 2 Jun 2020 12:31:25 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.9.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: linux-pm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-pm@vger.kernel.org Hi Daniel, On 6/1/20 10:44 PM, Daniel Lezcano wrote: > On 27/05/2020 11:58, Lukasz Luba wrote: >> Add support for other devices than CPUs. The registration function >> does not require a valid cpumask pointer and is ready to handle new >> devices. Some of the internal structures has been reorganized in order to >> keep consistent view (like removing per_cpu pd pointers). >> >> Signed-off-by: Lukasz Luba >> --- > > [ ... ] > >> } >> EXPORT_SYMBOL_GPL(em_register_perf_domain); >> + >> +/** >> + * em_dev_unregister_perf_domain() - Unregister Energy Model (EM) for a device >> + * @dev : Device for which the EM is registered >> + * >> + * Try to unregister the EM for the specified device (but not a CPU). >> + */ >> +void em_dev_unregister_perf_domain(struct device *dev) >> +{ >> + if (IS_ERR_OR_NULL(dev) || !dev->em_pd) >> + return; >> + >> + if (_is_cpu_device(dev)) >> + return; >> + >> + mutex_lock(&em_pd_mutex); > > Is the mutex really needed? I just wanted to align this unregister code with register. Since there is debugfs dir lookup and the device's EM existence checks I thought it wouldn't harm just to lock for a while and make sure the registration path is not used. These two paths shouldn't affect each other, but with modules loading/unloading I wanted to play safe. I can change it maybe to just dmb() and the end of the function if it's a big performance problem in this unloading path. What do you think? > > If this function is called that means there is no more user of the > em_pd, no? True, that EM users should already be unregistered i.e. thermal cooling. > >> + em_debug_remove_pd(dev); >> + >> + kfree(dev->em_pd->table); >> + kfree(dev->em_pd); >> + dev->em_pd = NULL; >> + mutex_unlock(&em_pd_mutex); >> +} >> +EXPORT_SYMBOL_GPL(em_dev_unregister_perf_domain); >> > > Thank you for reviewing this. Regards, Lukasz