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=-1.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS autolearn=ham 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 7B4CEC4321D for ; Wed, 15 Aug 2018 15:02:50 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 664942054F for ; Wed, 15 Aug 2018 15:02:48 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 664942054F Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=arm.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729515AbeHORzR (ORCPT ); Wed, 15 Aug 2018 13:55:17 -0400 Received: from usa-sjc-mx-foss1.foss.arm.com ([217.140.101.70]:55888 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729436AbeHORzR (ORCPT ); Wed, 15 Aug 2018 13:55:17 -0400 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.72.51.249]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 52A0A80D; Wed, 15 Aug 2018 08:02:47 -0700 (PDT) Received: from [0.0.0.0] (e107985-lin.emea.arm.com [10.4.12.239]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 0E5333F5BD; Wed, 15 Aug 2018 08:02:43 -0700 (PDT) Subject: Re: [PATCH v3 04/14] sched/core: uclamp: update CPU's refcount on clamp changes To: Patrick Bellasi , linux-kernel@vger.kernel.org, linux-pm@vger.kernel.org Cc: Ingo Molnar , Peter Zijlstra , Tejun Heo , "Rafael J . Wysocki" , Viresh Kumar , Vincent Guittot , Paul Turner , Morten Rasmussen , Juri Lelli , Todd Kjos , Joel Fernandes , Steve Muckle , Suren Baghdasaryan References: <20180806163946.28380-1-patrick.bellasi@arm.com> <20180806163946.28380-5-patrick.bellasi@arm.com> From: Dietmar Eggemann Message-ID: <4023267d-be06-c599-136e-1f70bf376d5d@arm.com> Date: Wed, 15 Aug 2018 17:02:42 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.9.1 MIME-Version: 1.0 In-Reply-To: <20180806163946.28380-5-patrick.bellasi@arm.com> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-GB Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 08/06/2018 06:39 PM, Patrick Bellasi wrote: [...] > +/** > + * uclamp_task_active: check if a task is currently clamping a CPU > + * @p: the task to check > + * > + * A task actively affects the utilization clamp of a CPU if: > + * - it's currently enqueued or running on that CPU > + * - it's refcounted in at least one clamp group of that CPU > + * > + * Return: true if p is currently clamping the utilization of its CPU. > + */ > +static inline bool uclamp_task_active(struct task_struct *p) > +{ > + struct rq *rq = task_rq(p); > + int clamp_id; > + > + lockdep_assert_held(&p->pi_lock); > + lockdep_assert_held(&rq->lock); > + > + if (!task_on_rq_queued(p) && !p->on_cpu) > + return false; > + > + for (clamp_id = 0; clamp_id < UCLAMP_CNT; ++clamp_id) { > + if (uclamp_task_affects(p, clamp_id)) > + return true; > + } > + > + return false; > +} Looks like that uclamp_task_active() is only used once (in uclamp_task_update_active()). Can you not code the if condition and the for loop directly in uclamp_task_update_active()? This would save code (lockdep_assert_held() etc.) and comment lines. [...]