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=-15.2 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,NICE_REPLY_A,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED, USER_AGENT_SANE_1 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 47C10C433B4 for ; Mon, 3 May 2021 12:53:57 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 039A26121D for ; Mon, 3 May 2021 12:53:56 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233869AbhECMxt (ORCPT ); Mon, 3 May 2021 08:53:49 -0400 Received: from foss.arm.com ([217.140.110.172]:40152 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233834AbhECMxe (ORCPT ); Mon, 3 May 2021 08:53:34 -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 D57481063; Mon, 3 May 2021 05:52:39 -0700 (PDT) Received: from [192.168.178.6] (unknown [172.31.20.19]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 460E73F70D; Mon, 3 May 2021 05:52:37 -0700 (PDT) Subject: Re: [PATCH v2 2/2] sched/fair: Fix negative energy delta in find_energy_efficient_cpu() To: Pierre.Gondois@arm.com, linux-kernel@vger.kernel.org, xuewen.yan@unisoc.com, qperret@qperret.net Cc: Lukasz.Luba@arm.com, Vincent.Donnefort@arm.com, mingo@redhat.com, peterz@infradead.org, juri.lelli@redhat.com, vincent.guittot@linaro.org, rostedt@goodmis.org, bsegall@google.com, mgorman@suse.de, bristot@redhat.com References: <20210429101948.31224-1-Pierre.Gondois@arm.com> <20210429101948.31224-3-Pierre.Gondois@arm.com> From: Dietmar Eggemann Message-ID: <013382c7-bccf-9e49-4a6b-5542cdd4abba@arm.com> Date: Mon, 3 May 2021 14:52:35 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Thunderbird/78.7.1 MIME-Version: 1.0 In-Reply-To: <20210429101948.31224-3-Pierre.Gondois@arm.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 29/04/2021 12:19, Pierre.Gondois@arm.com wrote: > From: Pierre Gondois [...] > @@ -6680,25 +6686,23 @@ static int find_energy_efficient_cpu(struct task_struct *p, int prev_cpu) > } > } > } > -unlock: > + No need for empty line. > rcu_read_unlock(); > > /* > * Pick the best CPU if prev_cpu cannot be used, or if it saves at > * least 6% of the energy used by prev_cpu. > */ > - if (prev_delta == ULONG_MAX) > - return best_energy_cpu; > - > - if ((prev_delta - best_delta) > ((prev_delta + base_energy) >> 4)) > - return best_energy_cpu; > + if ((prev_delta == ULONG_MAX) || > + (prev_delta - best_delta) > ((prev_delta + base_energy) >> 4)) > + target = best_energy_cpu; if ((prev_delta == ULONG_MAX) || - (prev_delta - best_delta) > ((prev_delta + base_energy) >> 4)) + (prev_delta - best_delta) > ((prev_delta + base_energy) >> 4)) target = best_energy_cpu; IMHO, using whitespaces to align both sub-conditions here makes it more readable. Especially since braces aren't required around single statements with a condition spanning over multiple lines. [...] With these minor things sorted: Reviewed-by: Dietmar Eggemann