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=-9.9 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,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 6B364C35656 for ; Fri, 21 Feb 2020 13:27:37 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 2DCB82073A for ; Fri, 21 Feb 2020 13:27:37 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=linaro.org header.i=@linaro.org header.b="CUM+1FS1" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728663AbgBUN1f (ORCPT ); Fri, 21 Feb 2020 08:27:35 -0500 Received: from mail-wm1-f68.google.com ([209.85.128.68]:52347 "EHLO mail-wm1-f68.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728235AbgBUN1e (ORCPT ); Fri, 21 Feb 2020 08:27:34 -0500 Received: by mail-wm1-f68.google.com with SMTP id p9so1799352wmc.2 for ; Fri, 21 Feb 2020 05:27:32 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linaro.org; s=google; h=from:to:cc:subject:date:message-id:in-reply-to:references; bh=2jv58e7XYQhyiOZ8oB+F6DiHwvlWPcUvM4iYr9/nM+k=; b=CUM+1FS1wIwzwu76hP5YN1+YQ0C2iku0Lx7PsSOXrOAsEKmXQOismOAzpVoD4QiLnl fIJMk5FHHupX+IOXTFXB/9yraI4Knu4j7Y9xZLd7DTnT5AyzQgSnj/w6YJWD/fJW5zlT DjcMBhsMjHk6//0Wwjz2cPZyZZi9XOfywDvZnksKiInytQxOCooARMIeXuS+yoEeng5o JF1DZeWT9r8jguTw4bQJ0cP7H09ytIsFJbuMolUHuawB9otw94ES0eamwGDT6MeU6Uf1 6rsjyD4R/5rBBEsQGUe8kpUTyS2UWVYPu+ih1rAGKmLZ0jGlpXoAKZ7l1aoLxeVVGaOH lbaA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references; bh=2jv58e7XYQhyiOZ8oB+F6DiHwvlWPcUvM4iYr9/nM+k=; b=Q5InxM650w6wEbFTGLHxSaOvKuiNUBu4Mqs5V6HrNVlBkyJ41QCVzj3GmH/2CEO0NC ZKMfJkylhBf5v4e1RkMarSQ6TAZY7X6ZqZ/jLuOqd3PFu+fGzWNF4JjwXpB0nfzSH04i 2Tk9G4eU/+VgOPbt3BSiFVXqVpLOrZF5u0xTNMW8HETMN46i3eSi7TzB0X3i/RqsvnVM 8yk2q9g7EqUzi8PP45r5O/jqfneNZKW944l8LFehBu0Q6AZDjluVSEp7c3iOZ+c5hUtc Sf3jx3JL2yQfF15KtTJCcoOI1edyIIWnnQsM2wIRj0EjRP3Lc0RTxk9nz1qSKlSkcMvK 8yyA== X-Gm-Message-State: APjAAAWnXStypfeapvpU/alq6t7zTr2t9APsjniux0nv5jreMgyX9K47 PKuOywThV+B2OkbK+bB7Lf569g== X-Google-Smtp-Source: APXvYqwHNTLCbACEbRn63ByOPDZJlbKSRBCR5E5GeowHzNIok84kpMsrScP4ydgUFy9Ua8Vf9LhCHw== X-Received: by 2002:a1c:6755:: with SMTP id b82mr4009982wmc.126.1582291652169; Fri, 21 Feb 2020 05:27:32 -0800 (PST) Received: from localhost.localdomain ([2a01:e0a:f:6020:1c35:eef1:1bd1:92a7]) by smtp.gmail.com with ESMTPSA id y185sm4058308wmg.2.2020.02.21.05.27.30 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 21 Feb 2020 05:27:31 -0800 (PST) From: Vincent Guittot To: mingo@redhat.com, peterz@infradead.org, juri.lelli@redhat.com, dietmar.eggemann@arm.com, rostedt@goodmis.org, bsegall@google.com, mgorman@suse.de, linux-kernel@vger.kernel.org Cc: pauld@redhat.com, parth@linux.ibm.com, valentin.schneider@arm.com, hdanton@sina.com, Vincent Guittot Subject: [PATCH v4 1/5] sched/fair: Reorder enqueue/dequeue_task_fair path Date: Fri, 21 Feb 2020 14:27:11 +0100 Message-Id: <20200221132715.20648-2-vincent.guittot@linaro.org> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20200221132715.20648-1-vincent.guittot@linaro.org> References: <20200221132715.20648-1-vincent.guittot@linaro.org> Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org The walk through the cgroup hierarchy during the enqueue/dequeue of a task is split in 2 distinct parts for throttled cfs_rq without any added value but making code less readable. Change the code ordering such that everything related to a cfs_rq (throttled or not) will be done in the same loop. In addition, the same steps ordering is used when updating a cfs_rq: - update_load_avg - update_cfs_group - update *h_nr_running This reordering enables the use of h_nr_running in PELT algorithm. No functional and performance changes are expected and have been noticed during tests. Signed-off-by: Vincent Guittot Reviewed-by: "Dietmar Eggemann " --- kernel/sched/fair.c | 42 ++++++++++++++++++++---------------------- 1 file changed, 20 insertions(+), 22 deletions(-) diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c index a7e11b1bb64c..27450c4ddc81 100644 --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -5259,32 +5259,31 @@ enqueue_task_fair(struct rq *rq, struct task_struct *p, int flags) cfs_rq = cfs_rq_of(se); enqueue_entity(cfs_rq, se, flags); - /* - * end evaluation on encountering a throttled cfs_rq - * - * note: in the case of encountering a throttled cfs_rq we will - * post the final h_nr_running increment below. - */ - if (cfs_rq_throttled(cfs_rq)) - break; cfs_rq->h_nr_running++; cfs_rq->idle_h_nr_running += idle_h_nr_running; + /* end evaluation on encountering a throttled cfs_rq */ + if (cfs_rq_throttled(cfs_rq)) + goto enqueue_throttle; + flags = ENQUEUE_WAKEUP; } for_each_sched_entity(se) { cfs_rq = cfs_rq_of(se); - cfs_rq->h_nr_running++; - cfs_rq->idle_h_nr_running += idle_h_nr_running; + /* end evaluation on encountering a throttled cfs_rq */ if (cfs_rq_throttled(cfs_rq)) - break; + goto enqueue_throttle; update_load_avg(cfs_rq, se, UPDATE_TG); update_cfs_group(se); + + cfs_rq->h_nr_running++; + cfs_rq->idle_h_nr_running += idle_h_nr_running; } +enqueue_throttle: if (!se) { add_nr_running(rq, 1); /* @@ -5345,17 +5344,13 @@ static void dequeue_task_fair(struct rq *rq, struct task_struct *p, int flags) cfs_rq = cfs_rq_of(se); dequeue_entity(cfs_rq, se, flags); - /* - * end evaluation on encountering a throttled cfs_rq - * - * note: in the case of encountering a throttled cfs_rq we will - * post the final h_nr_running decrement below. - */ - if (cfs_rq_throttled(cfs_rq)) - break; cfs_rq->h_nr_running--; cfs_rq->idle_h_nr_running -= idle_h_nr_running; + /* end evaluation on encountering a throttled cfs_rq */ + if (cfs_rq_throttled(cfs_rq)) + goto dequeue_throttle; + /* Don't dequeue parent if it has other entities besides us */ if (cfs_rq->load.weight) { /* Avoid re-evaluating load for this entity: */ @@ -5373,16 +5368,19 @@ static void dequeue_task_fair(struct rq *rq, struct task_struct *p, int flags) for_each_sched_entity(se) { cfs_rq = cfs_rq_of(se); - cfs_rq->h_nr_running--; - cfs_rq->idle_h_nr_running -= idle_h_nr_running; + /* end evaluation on encountering a throttled cfs_rq */ if (cfs_rq_throttled(cfs_rq)) - break; + goto dequeue_throttle; update_load_avg(cfs_rq, se, UPDATE_TG); update_cfs_group(se); + + cfs_rq->h_nr_running--; + cfs_rq->idle_h_nr_running -= idle_h_nr_running; } +dequeue_throttle: if (!se) sub_nr_running(rq, 1); -- 2.17.1