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=-9.7 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, UNPARSEABLE_RELAY,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 3F650C2BA19 for ; Tue, 14 Apr 2020 08:50:32 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 247F2206E9 for ; Tue, 14 Apr 2020 08:50:32 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2437045AbgDNIub (ORCPT ); Tue, 14 Apr 2020 04:50:31 -0400 Received: from out30-130.freemail.mail.aliyun.com ([115.124.30.130]:51972 "EHLO out30-130.freemail.mail.aliyun.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729365AbgDNIua (ORCPT ); Tue, 14 Apr 2020 04:50:30 -0400 X-Alimail-AntiSpam: AC=PASS;BC=-1|-1;BR=01201311R141e4;CH=green;DM=||false|;DS=||;FP=0|-1|-1|-1|0|-1|-1|-1;HT=e01e01355;MF=rocking@linux.alibaba.com;NM=1;PH=DS;RN=9;SR=0;TI=SMTPD_---0TvW-l9J_1586854193; Received: from localhost(mailfrom:rocking@linux.alibaba.com fp:SMTPD_---0TvW-l9J_1586854193) by smtp.aliyun-inc.com(127.0.0.1); Tue, 14 Apr 2020 16:50:23 +0800 From: Peng Wang To: mingo@redhat.com, peterz@infradead.org, juri.lelli@redhat.com, vincent.guittot@linaro.org, dietmar.eggemann@arm.com, rostedt@goodmis.org, bsegall@google.com, mgorman@suse.de Cc: linux-kernel@vger.kernel.org Subject: [PATCH v2] sched/fair: Simplify the code of should_we_balance() Date: Tue, 14 Apr 2020 16:48:19 +0800 Message-Id: X-Mailer: git-send-email 2.9.5 In-Reply-To: <245c792f0e580b3ca342ad61257f4c066ee0f84f.1586594833.git.rocking@linux.alibaba.com> References: <245c792f0e580b3ca342ad61257f4c066ee0f84f.1586594833.git.rocking@linux.alibaba.com> Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org We only consider group_balance_cpu() after there is no idle cpu. So, just do comparison before return at these two cases. Reviewed-by: Valentin Schneider Reviewed-by: Vincent Guittot Signed-off-by: Peng Wang --- kernel/sched/fair.c | 16 +++++----------- 1 file changed, 5 insertions(+), 11 deletions(-) diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c index 02f323b..c3f57f4 100644 --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -9409,7 +9409,7 @@ static int active_load_balance_cpu_stop(void *data); static int should_we_balance(struct lb_env *env) { struct sched_group *sg = env->sd->groups; - int cpu, balance_cpu = -1; + int cpu; /* * Ensure the balancing environment is consistent; can happen @@ -9430,18 +9430,12 @@ static int should_we_balance(struct lb_env *env) if (!idle_cpu(cpu)) continue; - balance_cpu = cpu; - break; + /* Are we the first idle CPU? */ + return cpu == env->dst_cpu; } - if (balance_cpu == -1) - balance_cpu = group_balance_cpu(sg); - - /* - * First idle CPU or the first CPU(busiest) in this sched group - * is eligible for doing load balancing at this and above domains. - */ - return balance_cpu == env->dst_cpu; + /* Are we the first CPU in the balance mask of this group? */ + return group_balance_cpu(sg) == env->dst_cpu; } /* -- 2.9.5