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=-2.3 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 AC408C54FCB for ; Thu, 23 Apr 2020 16:58:24 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 8D03E216FD for ; Thu, 23 Apr 2020 16:58:24 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729834AbgDWQ6X (ORCPT ); Thu, 23 Apr 2020 12:58:23 -0400 Received: from foss.arm.com ([217.140.110.172]:44234 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729674AbgDWQ6X (ORCPT ); Thu, 23 Apr 2020 12:58:23 -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 85EE330E; Thu, 23 Apr 2020 09:58:22 -0700 (PDT) Received: from [10.37.12.89] (unknown [10.37.12.89]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 8B9B73F68F; Thu, 23 Apr 2020 09:57:48 -0700 (PDT) Subject: Re: [PATCH v6 04/10] PM / EM: add support for other devices than CPUs in Energy Model To: Daniel Lezcano Cc: 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, 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: <20200410084210.24932-1-lukasz.luba@arm.com> <20200410084210.24932-5-lukasz.luba@arm.com> <20200423151250.GB65632@linaro.org> From: Lukasz Luba Message-ID: Date: Thu, 23 Apr 2020 17:57:45 +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: <20200423151250.GB65632@linaro.org> 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 4/23/20 4:12 PM, Daniel Lezcano wrote: > On Fri, Apr 10, 2020 at 09:42:04AM +0100, Lukasz Luba wrote: >> Add support for other devices that 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). To track usage >> of the Energy Model structures, they are protected with kref. > > Why not add the energy model structure in the struct device directly? Do you mean this structure? https://elixir.bootlin.com/linux/latest/source/include/linux/device.h#L537 and to put something like: struct device { ... struct dev_pm_domain *pm_domain; #ifdef CONFIG_ENERGY_MODEL struct em_perf_domain *em_pd; #endif ... }; > > For instance for the em_cpu_get() function, the cpu id allows to retrieve the > cpu device and then from there, the energy model instead of browsing another > list. The em_device life cycle will be tied to the struct device. That would be perfect. > > Then when the struct device and the em_device are connected, add the debugfs > with a struct device list for those which are energy aware, so you end up with > a structure: > > struct em_device { > struct device *dev; > struct list_head em_dev_list; > }; > > (a global single dentry for debugfs to do a recursive delete is enough). > > Locks when inspecting and add/removal called from the struct device release > function. So no need of an extra refcounting. > > Does it make sense? > Indeed it looks much cleaner/simpler. I will try to address this idea and get rid of refcounting. This should be doable in this patch (4/10). In the v7 I will keep your ACKs for other patches that you have already commented. Thank you for your suggestions and review. Regards, Lukasz