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=-15.7 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 DE6CAC433DB for ; Thu, 25 Feb 2021 11:47:41 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 931BF64EBD for ; Thu, 25 Feb 2021 11:47:41 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233820AbhBYLrg (ORCPT ); Thu, 25 Feb 2021 06:47:36 -0500 Received: from foss.arm.com ([217.140.110.172]:55646 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232778AbhBYLr2 (ORCPT ); Thu, 25 Feb 2021 06:47:28 -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 EF107D6E; Thu, 25 Feb 2021 03:46:41 -0800 (PST) Received: from [192.168.1.15] (unknown [172.31.20.19]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 504733F73D; Thu, 25 Feb 2021 03:46:40 -0800 (PST) Subject: Re: [PATCH v2 2/2] sched/fair: use lsub_positive in cpu_util_next() To: vincent.donnefort@arm.com, peterz@infradead.org, mingo@redhat.com, vincent.guittot@linaro.org Cc: linux-kernel@vger.kernel.org, qperret@google.com, patrick.bellasi@matbug.net, valentin.schneider@arm.com References: <20210225083612.1113823-1-vincent.donnefort@arm.com> <20210225083612.1113823-3-vincent.donnefort@arm.com> From: Dietmar Eggemann Message-ID: <6bf917f3-1581-25ca-1330-3084194a4973@arm.com> Date: Thu, 25 Feb 2021 12:46:30 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.10.0 MIME-Version: 1.0 In-Reply-To: <20210225083612.1113823-3-vincent.donnefort@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 25/02/2021 09:36, vincent.donnefort@arm.com wrote: > From: Vincent Donnefort > > The sub_positive local version is saving an explicit load-store and is > enough for the cpu_util_next() usage. > > Signed-off-by: Vincent Donnefort > > diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c > index 146ac9fec4b6..1364f8b95214 100644 > --- a/kernel/sched/fair.c > +++ b/kernel/sched/fair.c > @@ -6525,7 +6525,7 @@ static unsigned long cpu_util_next(int cpu, struct task_struct *p, int dst_cpu) > * util_avg should already be correct. > */ > if (task_cpu(p) == cpu && dst_cpu != cpu) > - sub_positive(&util, task_util(p)); > + lsub_positive(&util, task_util(p)); > else if (task_cpu(p) != cpu && dst_cpu == cpu) > util += task_util(p); Reviewed-by: Dietmar Eggemann