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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 91095C38A2D for ; Tue, 25 Oct 2022 03:16:43 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230188AbiJYDQm (ORCPT ); Mon, 24 Oct 2022 23:16:42 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:51394 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230005AbiJYDQj (ORCPT ); Mon, 24 Oct 2022 23:16:39 -0400 Received: from mail-pj1-x1029.google.com (mail-pj1-x1029.google.com [IPv6:2607:f8b0:4864:20::1029]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 1C8CF29807 for ; Mon, 24 Oct 2022 20:16:38 -0700 (PDT) Received: by mail-pj1-x1029.google.com with SMTP id m2so5653849pjr.3 for ; Mon, 24 Oct 2022 20:16:38 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=bytedance-com.20210112.gappssmtp.com; s=20210112; h=content-transfer-encoding:in-reply-to:from:references:cc:to:subject :user-agent:mime-version:date:message-id:from:to:cc:subject:date :message-id:reply-to; bh=yt6csZKjyFbh3Av74KUaYS0trbNlNlUkWTp5o72OjTg=; b=fDGCHneHUqElVQPodFdPJtrvhFmLUBq0JUMOcfxyXjoV747t1v+9IDwLIA2L3kB50G Lf/LFJJjucoayWTbObOguSKZs1aU+KUPdvTlrGpy1rOxGBdS70xHTniN9j/0M3Yf3zHO 7v6liLN68PxvDtyeX35Pd5YO3VkDKWv1+FzWZ5XLo1xqtsK+y5yHZJ5Jq1Y5U6hiNeAg aozUcIiVO5d8tVlxXX8UtpNDNWK6Eu5nlxr2relBGWV8agl11Fn71alKk+Z6+/BASxG0 w56LXiCsY/Hv4nGvQWnAyH5lvyeHcUv/l8t2hKBWarSH6dqpdjVjXaTjm7FQIaxYsd8m fRBQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=content-transfer-encoding:in-reply-to:from:references:cc:to:subject :user-agent:mime-version:date:message-id:x-gm-message-state:from:to :cc:subject:date:message-id:reply-to; bh=yt6csZKjyFbh3Av74KUaYS0trbNlNlUkWTp5o72OjTg=; b=CgFuYekqTvwYxj+TMwzx3Qqr9nMxEqlBzNain6vMr1MiWw1PPxhv7/gXPYKV6GJ4+n 6rhgQQ2WKmMSMfy/N+6fUtTNiKMpFiU7Kv4sW1Q2CWIbM/XwaLuujjXnIXNQFCfmj8hE yeil0Q59HxDg3dtRMH+vcLL0CxQhys9P4a/NpkTTHgcLkkzaIwUx9/L5fMDb1/RSQ330 e06FrtrWGnFdavJPsvELeiMSk7BLfGkd+JZ7RSr5/vhwHqNEZO60gUNBCOV9z8WGMNEO Yev2wFyrjWrqDoSKYmS61ctgf1+CJCePf3rOrUYEL2Jm+lLtJo327cjSW4iUVf09fFCM yEcg== X-Gm-Message-State: ACrzQf1YXuDTbSrYEeA+CH5GZ8jJ9D7thdEqdFHlafRYXsriHhKobk7C D2tyVKERA9CtIxzNKf8SEQMoenft1ZQkadwb X-Google-Smtp-Source: AMsMyM50JW+u5z1CIhPwUgy1Vv7ZiEcV8QEpbd12R6DcKaL24S6fQLLoWhXRfAt5d/oRQBKc0xIACQ== X-Received: by 2002:a17:90b:1bcb:b0:20d:75b8:ee64 with SMTP id oa11-20020a17090b1bcb00b0020d75b8ee64mr41969744pjb.162.1666667797632; Mon, 24 Oct 2022 20:16:37 -0700 (PDT) Received: from [10.85.115.102] ([139.177.225.228]) by smtp.gmail.com with ESMTPSA id p25-20020a635b19000000b0044a4025cea1sm391718pgb.90.2022.10.24.20.16.32 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Mon, 24 Oct 2022 20:16:37 -0700 (PDT) Message-ID: Date: Tue, 25 Oct 2022 11:16:29 +0800 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.15; rv:91.0) Gecko/20100101 Thunderbird/91.13.1 Subject: Re: [External] Re: [PATCH 1/2] sched/numa: Stop an exhastive search if an idle core is found To: Mel Gorman Cc: mingo@redhat.com, peterz@infradead.org, mingo@kernel.org, juri.lelli@redhat.com, vincent.guittot@linaro.org, dietmar.eggemann@arm.com, rostedt@goodmis.org, bsegall@google.com, bristot@redhat.com, vschneid@redhat.com, mgorman@techsingularity.net, linux-kernel@vger.kernel.org References: <20221021061558.34767-1-jiahao.os@bytedance.com> <20221021061558.34767-2-jiahao.os@bytedance.com> <20221024133435.e2kajx5k7jzznp25@suse.de> From: Hao Jia In-Reply-To: <20221024133435.e2kajx5k7jzznp25@suse.de> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 2022/10/24 Mel Gorman wrote: > On Fri, Oct 21, 2022 at 02:15:57PM +0800, Hao Jia wrote: >> In update_numa_stats() we try to find an idle cpu on the NUMA node, >> preferably an idle core. When we find an idle core, >> we can stop searching. >> >> Signed-off-by: Hao Jia >> --- >> kernel/sched/fair.c | 8 ++++---- >> 1 file changed, 4 insertions(+), 4 deletions(-) >> >> diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c >> index e4a0b8bd941c..b7cbec539c77 100644 >> --- a/kernel/sched/fair.c >> +++ b/kernel/sched/fair.c >> @@ -1792,7 +1792,7 @@ static void update_numa_stats(struct task_numa_env *env, >> ns->nr_running += rq->cfs.h_nr_running; >> ns->compute_capacity += capacity_of(cpu); >> >> - if (find_idle && !rq->nr_running && idle_cpu(cpu)) { >> + if (find_idle && idle_core < 0 && !rq->nr_running && idle_cpu(cpu)) { >> if (READ_ONCE(rq->numa_migrate_on) || >> !cpumask_test_cpu(cpu, env->p->cpus_ptr)) >> continue; >> @@ -1801,6 +1801,9 @@ static void update_numa_stats(struct task_numa_env *env, >> ns->idle_cpu = cpu; >> >> idle_core = numa_idle_core(idle_core, cpu); >> + /* If we find an idle core, stop searching. */ >> + if (idle_core >= 0) >> + ns->idle_cpu = idle_core; >> } >> } >> rcu_read_unlock(); >> @@ -1808,9 +1811,6 @@ static void update_numa_stats(struct task_numa_env *env, >> ns->weight = cpumask_weight(cpumask_of_node(nid)); >> >> ns->node_type = numa_classify(env->imbalance_pct, ns); >> - >> - if (idle_core >= 0) >> - ns->idle_cpu = idle_core; >> } >> > > Remove the change in the first hunk and call break in the second hunk > after updating ns->idle_cpu. > Yes, thanks for your review. If I understand correctly, some things might look like this. diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c index e4a0b8bd941c..dfcb620bfe50 100644 --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -1792,7 +1792,7 @@ static void update_numa_stats(struct task_numa_env *env, ns->nr_running += rq->cfs.h_nr_running; ns->compute_capacity += capacity_of(cpu); - if (find_idle && !rq->nr_running && idle_cpu(cpu)) { + if (find_idle && idle_core < 0 && !rq->nr_running && idle_cpu(cpu)) { if (READ_ONCE(rq->numa_migrate_on) || !cpumask_test_cpu(cpu, env->p->cpus_ptr)) continue; Thanks, Hao