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=-2.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=no 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 AADE7C33CAA for ; Tue, 21 Jan 2020 10:49:33 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 8551E22522 for ; Tue, 21 Jan 2020 10:49:33 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729578AbgAUKtc (ORCPT ); Tue, 21 Jan 2020 05:49:32 -0500 Received: from foss.arm.com ([217.140.110.172]:41480 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728792AbgAUKtc (ORCPT ); Tue, 21 Jan 2020 05:49:32 -0500 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 553431FB; Tue, 21 Jan 2020 02:49:31 -0800 (PST) Received: from [10.37.12.169] (unknown [10.37.12.169]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 61FC23F6C4; Tue, 21 Jan 2020 02:49:21 -0800 (PST) Subject: Re: [PATCH 1/4] PM / EM: and devices to Energy Model To: Quentin Perret Cc: Dietmar Eggemann , 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, Morten.Rasmussen@arm.com, Chris.Redpath@arm.com, ionela.voinescu@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, daniel.lezcano@linaro.org, mingo@redhat.com, peterz@infradead.org, juri.lelli@redhat.com, vincent.guittot@linaro.org, rostedt@goodmis.org, 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, patrick.bellasi@matbug.net References: <20200116152032.11301-1-lukasz.luba@arm.com> <20200116152032.11301-2-lukasz.luba@arm.com> <17b77e0c-9455-0479-d37b-c57717c784c7@arm.com> <20200120152804.GB164543@google.com> <453034e5-f7b9-20f7-4e26-5d0d7164edd1@arm.com> <20200121100854.GB157387@google.com> From: Lukasz Luba Message-ID: <5621c137-7057-1d5c-646a-95707105df25@arm.com> Date: Tue, 21 Jan 2020 10:49:19 +0000 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: <20200121100854.GB157387@google.com> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 1/21/20 10:08 AM, Quentin Perret wrote: > On Monday 20 Jan 2020 at 16:20:49 (+0000), Lukasz Luba wrote: >> On 1/20/20 3:28 PM, Quentin Perret wrote: >>> Agreed, this looks a bit confusing. It should be trivial to make >>> em_dev_get() (or whatever we end up calling it) work for CPUs too, >>> though. And we could always have a em_cpu_get(int cpu) API that is a >>> basically a wrapper around em_dev_get() for convenience. >> >> The problem not only here is that we have a CPU index 'int cpu' >> and if we ask for device like: >> >> struct device *dev = get_cpu_device(cpu); >> >> It might be not the same device that was used during the >> registration, when we had i.e. 4 CPUs for the same policy: >> >> int cpu_id = cpumask_first(policy->cpus); >> struct device *cpu_dev = get_cpu_device(cpu_id); >> em_register_perf_domain(cpu_dev, nr_opp, &em_cb); >> >> That's why the em_cpu_get() is different than em_get_pd(), mainly by: >> if (cpumask_test_cpu(cpu, em_span_cpus(em_pd))) >> >> It won't be simple wrapper, let me think how it could be handled >> differently than it is now. > > Right so I suppose the easiest solution would be to do the opposite of > my first suggestion. That is, make em_get_pd() call em_cpu_get() if the > device is a CPU device, or proceed to the PD list iteration for other > devices. And em_cpu_get() can remain as you originally suggested (that > is, iterate over the PDs and test the mask). Exactly, something like: ---------------------------->8------------------------- 288 struct em_perf_domain *em_get_pd(struct device *dev) 289 { 290 struct em_device *em_dev; 291 292 if (IS_ERR_OR_NULL(dev)) 293 return NULL; 294 295 if (_is_cpu_device(dev)) 296 return em_cpu_get(dev->id); .... ------------------------8<----------------------------- > > That should ensure em_get_pd() always works, em_cpu_get() is still there > handy for the scheduler and such, and the two EM lookup functions (for > CPUs or for devices) are kept cleanly separated. > > Thoughts ? Agree. Then we can have these two functions and em_get_pd() will also work fine. > > Thanks, > Quentin > Regards, Lukasz