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=-2.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT 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 B7507C3279B for ; Wed, 4 Jul 2018 10:18:36 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 7845D23BFB for ; Wed, 4 Jul 2018 10:18:36 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 7845D23BFB 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 S934643AbeGDKSc (ORCPT ); Wed, 4 Jul 2018 06:18:32 -0400 Received: from foss.arm.com ([217.140.101.70]:35112 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S934329AbeGDKSa (ORCPT ); Wed, 4 Jul 2018 06:18:30 -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 5A5FF1650; Wed, 4 Jul 2018 03:18:30 -0700 (PDT) Received: from e105550-lin.cambridge.arm.com (e105550-lin.cambridge.arm.com [10.1.211.30]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPA id D63183F5AD; Wed, 4 Jul 2018 03:18:28 -0700 (PDT) From: Morten Rasmussen To: peterz@infradead.org, mingo@redhat.com Cc: valentin.schneider@arm.com, dietmar.eggemann@arm.com, vincent.guittot@linaro.org, gaku.inami.xh@renesas.com, linux-kernel@vger.kernel.org, Morten Rasmussen Subject: [PATCHv4 11/12] sched/core: Disable SD_ASYM_CPUCAPACITY for root_domains without asymmetry Date: Wed, 4 Jul 2018 11:17:49 +0100 Message-Id: <1530699470-29808-12-git-send-email-morten.rasmussen@arm.com> X-Mailer: git-send-email 2.7.4 In-Reply-To: <1530699470-29808-1-git-send-email-morten.rasmussen@arm.com> References: <1530699470-29808-1-git-send-email-morten.rasmussen@arm.com> Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org When hotplugging cpus out or creating exclusive cpusets (disabling sched_load_balance) systems which were asymmetric at boot might become symmetric. In this case leaving the flag set might lead to suboptimal scheduling decisions. The arch-code proving the flag doesn't have visibility of the cpuset configuration so it must either be told by passing a cpumask or the generic topology code has to verify if the flag should still be set when taking the actual sched_domain_span() into account. This patch implements the latter approach. We need to detect capacity based on calling arch_scale_cpu_capacity() directly as rq->cpu_capacity_orig hasn't been set yet early in the boot process. cc: Ingo Molnar cc: Peter Zijlstra Signed-off-by: Morten Rasmussen --- kernel/sched/topology.c | 20 ++++++++++++++++++++ 1 file changed, 20 insertions(+) diff --git a/kernel/sched/topology.c b/kernel/sched/topology.c index 71330e0e41db..29c186961345 100644 --- a/kernel/sched/topology.c +++ b/kernel/sched/topology.c @@ -1160,6 +1160,26 @@ sd_init(struct sched_domain_topology_level *tl, sd_id = cpumask_first(sched_domain_span(sd)); /* + * Check if cpu_map eclipses cpu capacity asymmetry. + */ + + if (sd->flags & SD_ASYM_CPUCAPACITY) { + int i; + bool disable = true; + long capacity = arch_scale_cpu_capacity(NULL, sd_id); + + for_each_cpu(i, sched_domain_span(sd)) { + if (capacity != arch_scale_cpu_capacity(NULL, i)) { + disable = false; + break; + } + } + + if (disable) + sd->flags &= ~SD_ASYM_CPUCAPACITY; + } + + /* * Convert topological properties into behaviour. */ -- 2.7.4