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 5753FC43603 for ; Wed, 11 Dec 2019 16:53:26 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 3541F214AF for ; Wed, 11 Dec 2019 16:53:26 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730607AbfLKQxY (ORCPT ); Wed, 11 Dec 2019 11:53:24 -0500 Received: from foss.arm.com ([217.140.110.172]:39086 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730058AbfLKQxY (ORCPT ); Wed, 11 Dec 2019 11:53:24 -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 06AEC30E; Wed, 11 Dec 2019 08:53:24 -0800 (PST) Received: from [10.1.194.37] (e113632-lin.cambridge.arm.com [10.1.194.37]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 579783F52E; Wed, 11 Dec 2019 08:53:23 -0800 (PST) Subject: Re: [RFC PATCH 4/7] sched/fair: Dissociate wakeup decisions from SD flag value From: Valentin Schneider To: linux-kernel@vger.kernel.org Cc: mingo@redhat.com, peterz@infradead.org, vincent.guittot@linaro.org, dietmar.eggemann@arm.com References: <20191211164401.5013-1-valentin.schneider@arm.com> <20191211164401.5013-5-valentin.schneider@arm.com> Message-ID: <26381004-06f5-a006-1e30-49e5e3d4f8d8@arm.com> Date: Wed, 11 Dec 2019 16:53:22 +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: <20191211164401.5013-5-valentin.schneider@arm.com> Content-Type: text/plain; charset=utf-8 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 11/12/2019 16:43, Valentin Schneider wrote: > @@ -6396,9 +6396,8 @@ select_task_rq_fair(struct task_struct *p, int prev_cpu, int wake_flags) > if (unlikely(sd)) { > /* Slow path */ > new_cpu = find_idlest_cpu(sd, p, cpu, prev_cpu, sd_flag); > - } else if (sd_flag & SD_BALANCE_WAKE) { /* XXX always ? */ > + } else if (wake_flags & WF_TTWU) { /* XXX always ? */ While I'm at it, Dietmar pointed out to me that this is only really relevant to forkees and execees when a NULL domain is attached to the CPU (since sd_init() unconditionally sets SD_BALANCE_{FORK, EXEC}). So this only makes a difference when the SD hierarchy hasn't been built / is being rebuilt, or when cpusets are involved. So perhaps we could make that an unconditional else, or make forkees/execees bail out earlier. > /* Fast path */ > - > new_cpu = select_idle_sibling(p, prev_cpu, new_cpu); > > if (want_affine) >