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,URIBL_BLOCKED, 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 A70ECC2BA19 for ; Mon, 6 Apr 2020 13:30:14 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 7CA25221E8 for ; Mon, 6 Apr 2020 13:30:14 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728381AbgDFNaK (ORCPT ); Mon, 6 Apr 2020 09:30:10 -0400 Received: from foss.arm.com ([217.140.110.172]:45722 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728200AbgDFNaK (ORCPT ); Mon, 6 Apr 2020 09:30:10 -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 313E231B; Mon, 6 Apr 2020 06:30:09 -0700 (PDT) Received: from [10.37.12.4] (unknown [10.37.12.4]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id BC4473F7D8; Mon, 6 Apr 2020 06:29:58 -0700 (PDT) Subject: Re: [PATCH v5 1/5] PM / EM: add devices to 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: Morten.Rasmussen@arm.com, Dietmar.Eggemann@arm.com, javi.merino@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: <20200318114548.19916-1-lukasz.luba@arm.com> <20200318114548.19916-2-lukasz.luba@arm.com> <09b680a5-a118-8c6e-0ae1-03ab5f10c573@linaro.org> From: Lukasz Luba Message-ID: Date: Mon, 6 Apr 2020 14:29:56 +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: <09b680a5-a118-8c6e-0ae1-03ab5f10c573@linaro.org> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: linux-omap-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-omap@vger.kernel.org Hi Daniel, Thank you for the review. On 4/3/20 5:05 PM, Daniel Lezcano wrote: > > Hi Lukasz, > > > On 18/03/2020 12:45, Lukasz Luba wrote: >> Add support of other devices into the Energy Model framework not only the >> CPUs. Change the interface to be more unified which can handle other >> devices as well. > > thanks for taking care of that. Overall I like the changes in this patch > but it hard to review in details because the patch is too big :/ > > Could you split this patch into smaller ones? > > eg. (at your convenience) > > - One patch renaming s/cap/perf/ > > - One patch adding a new function: > > em_dev_register_perf_domain(struct device *dev, > unsigned int nr_states, > struct em_data_callback *cb); > > (+ EXPORT_SYMBOL_GPL) > > And em_register_perf_domain() using it. > > - One converting the em_register_perf_domain() user to > em_dev_register_perf_domain > > - One adding the different new 'em' functions > > - And finally one removing em_register_perf_domain(). I agree and will do the split. I could also break the dependencies for future easier merge. > > >> Acked-by: Quentin Perret >> Signed-off-by: Lukasz Luba >> --- > > [ ... ] > >> 2. Core APIs >> @@ -70,14 +72,16 @@ CONFIG_ENERGY_MODEL must be enabled to use the EM framework. >> Drivers are expected to register performance domains into the EM framework by >> calling the following API:: >> >> - int em_register_perf_domain(cpumask_t *span, unsigned int nr_states, >> - struct em_data_callback *cb); >> + int em_register_perf_domain(struct device *dev, unsigned int nr_states, >> + struct em_data_callback *cb, cpumask_t *cpus); > > Isn't possible to get rid of this cpumask by using > cpufreq_cpu_get() which returns the cpufreq's policy and from their get > the related cpus ? We had similar thoughts with Quentin and I've checked this. Unfortunately, if the policy is a 'new policy' [1] it gets allocated and passed into cpufreq driver ->init(policy) [2]. Then that policy is set into per_cpu pointer for each related_cpu [3]: for_each_cpu(j, policy->related_cpus) per_cpu(cpufreq_cpu_data, j) = policy; Thus, any calls of functions (i.e. cpufreq_cpu_get()) which try to take this ptr before [3] won't work. We are trying to register EM from cpufreq_driver->init(policy) and the per_cpu policy is likely to be not populated at that phase. Regards, Lukasz [1] https://elixir.bootlin.com/linux/latest/source/drivers/cpufreq/cpufreq.c#L1328 [2] https://elixir.bootlin.com/linux/latest/source/drivers/cpufreq/cpufreq.c#L1350 [3] https://elixir.bootlin.com/linux/latest/source/drivers/cpufreq/cpufreq.c#L1374