From patchwork Mon Sep 26 12:19:53 2016 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Vincent Guittot X-Patchwork-Id: 77027 Delivered-To: patch@linaro.org Received: by 10.140.106.72 with SMTP id d66csp1146138qgf; Mon, 26 Sep 2016 05:21:04 -0700 (PDT) X-Received: by 10.98.109.67 with SMTP id i64mr8584386pfc.85.1474892464268; Mon, 26 Sep 2016 05:21:04 -0700 (PDT) Return-Path: Received: from vger.kernel.org (vger.kernel.org. [209.132.180.67]) by mx.google.com with ESMTP id y15si25010652pfb.140.2016.09.26.05.21.03; Mon, 26 Sep 2016 05:21:04 -0700 (PDT) Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67; Authentication-Results: mx.google.com; dkim=pass header.i=@linaro.org; spf=pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=pass (p=NONE dis=NONE) header.from=linaro.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S941500AbcIZMUt (ORCPT + 27 others); Mon, 26 Sep 2016 08:20:49 -0400 Received: from mail-pa0-f42.google.com ([209.85.220.42]:34349 "EHLO mail-pa0-f42.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S941454AbcIZMUl (ORCPT ); Mon, 26 Sep 2016 08:20:41 -0400 Received: by mail-pa0-f42.google.com with SMTP id gp7so5461223pac.1 for ; Mon, 26 Sep 2016 05:20:41 -0700 (PDT) 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=r52vYq7Z6+KA5/XX6vYVm3VDrEMbNdYV9seabSU+JMU=; b=Xl3w/AqjzqFNtBJXDCmfY20ZJqXeYhSGbUQa08vo7AFC2m1BlrajUXdKi1ov/SfWVE kKa7CJ5nVDxZl1bSN+BV8Zu7DxvT0BiAghuTkdmRXFJ9H+VDw/QHwVKYwLZwWqSahdC1 vpiPpaGW1qVgyBYZ0I+BGTRzPb/gFD2lFgIsE= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20130820; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references; bh=r52vYq7Z6+KA5/XX6vYVm3VDrEMbNdYV9seabSU+JMU=; b=MEkKuwuaXmEwMN1zx3Ykg+kYILE1VSvqWyz4y/fsHOJSX7zgESS5IlmdD/tHGK/poU 84bXTpUVd0VAGftYgcmw0+QntWz4Ij5NFAJhs6wy6ysh6NuJpZC+Mk7gwda2r6xMmZtH H1Kz/G++JBnIFccI1y9ePc3/T//ViTBPixvIgUcg8l1lx6mu9moO7hwVIat23nxD6FIo cYttMIN0I54FLbheSdOrSz3WrmQdMgkDjhd3GdE4GccsLs/1WiLhDxBBCPtWvJs1yQUh HnKniK4ZELrfVHazl2OKr/vloR6amQWl8mRUVaCR8ryxA6caRQ8RslX4GFs6MgClzAUx yU7Q== X-Gm-Message-State: AE9vXwPCEMu2pLpq4IIwCq2RX/4uAN3+QZTCKng3SmPVinuC4BW4bJcgVv0iyTeyzLN7Y0VK X-Received: by 10.66.190.161 with SMTP id gr1mr37298098pac.156.1474892440847; Mon, 26 Sep 2016 05:20:40 -0700 (PDT) Received: from localhost.localdomain ([67.238.99.186]) by smtp.gmail.com with ESMTPSA id i62sm30773860pfg.89.2016.09.26.05.20.39 (version=TLS1_2 cipher=ECDHE-RSA-AES128-SHA bits=128/128); Mon, 26 Sep 2016 05:20:39 -0700 (PDT) From: Vincent Guittot To: peterz@infradead.org, mingo@kernel.org, linux-kernel@vger.kernel.org, dietmar.eggemann@arm.com, kernellwp@gmail.com Cc: yuyang.du@intel.com, Morten.Rasmussen@arm.com, linaro-kernel@lists.linaro.org, pjt@google.com, bsegall@google.com, Vincent Guittot Subject: [PATCH 7/7 v4] sched: fix wrong utilization accounting when switching to fair class Date: Mon, 26 Sep 2016 14:19:53 +0200 Message-Id: <1474892393-5095-8-git-send-email-vincent.guittot@linaro.org> X-Mailer: git-send-email 1.9.1 In-Reply-To: <1474892393-5095-1-git-send-email-vincent.guittot@linaro.org> References: <1474892393-5095-1-git-send-email-vincent.guittot@linaro.org> Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org When a task switches to fair scheduling class, the period between now and the last update of its utilization is accounted as running time whatever happened during this period. This wrong accounting applies to the task and also to the task group branch. When changing the property of a running task like its list of allowed CPUs or its scheduling class, we follow the sequence: -dequeue task -put task -change the property -set task as current task -enqueue task The end of the sequence doesn't follow the normal sequence which is : -enqueue a task -then set the task as current task. This wrong ordering is the root cause of wrong utilization accounting. Update the sequence to follow the right one: -dequeue task -put task -change the property -enqueue task -set task as current task Signed-off-by: Vincent Guittot --- kernel/sched/core.c | 20 ++++++++++---------- 1 file changed, 10 insertions(+), 10 deletions(-) -- 1.9.1 diff --git a/kernel/sched/core.c b/kernel/sched/core.c index 3e52d08..7a9c9b9 100644 --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -1105,10 +1105,10 @@ void do_set_cpus_allowed(struct task_struct *p, const struct cpumask *new_mask) p->sched_class->set_cpus_allowed(p, new_mask); - if (running) - p->sched_class->set_curr_task(rq); if (queued) enqueue_task(rq, p, ENQUEUE_RESTORE); + if (running) + p->sched_class->set_curr_task(rq); } /* @@ -3687,10 +3687,10 @@ void rt_mutex_setprio(struct task_struct *p, int prio) p->prio = prio; - if (running) - p->sched_class->set_curr_task(rq); if (queued) enqueue_task(rq, p, queue_flag); + if (running) + p->sched_class->set_curr_task(rq); check_class_changed(rq, p, prev_class, oldprio); out_unlock: @@ -4243,8 +4243,6 @@ static int __sched_setscheduler(struct task_struct *p, prev_class = p->sched_class; __setscheduler(rq, p, attr, pi); - if (running) - p->sched_class->set_curr_task(rq); if (queued) { /* * We enqueue to tail when the priority of a task is @@ -4255,6 +4253,8 @@ static int __sched_setscheduler(struct task_struct *p, enqueue_task(rq, p, queue_flags); } + if (running) + p->sched_class->set_curr_task(rq); check_class_changed(rq, p, prev_class, oldprio); preempt_disable(); /* avoid rq from going away on us */ @@ -5417,10 +5417,10 @@ void sched_setnuma(struct task_struct *p, int nid) p->numa_preferred_nid = nid; - if (running) - p->sched_class->set_curr_task(rq); if (queued) enqueue_task(rq, p, ENQUEUE_RESTORE); + if (running) + p->sched_class->set_curr_task(rq); task_rq_unlock(rq, p, &rf); } #endif /* CONFIG_NUMA_BALANCING */ @@ -7868,10 +7868,10 @@ void sched_move_task(struct task_struct *tsk) sched_change_group(tsk, TASK_MOVE_GROUP); - if (unlikely(running)) - tsk->sched_class->set_curr_task(rq); if (queued) enqueue_task(rq, tsk, ENQUEUE_RESTORE | ENQUEUE_MOVE); + if (unlikely(running)) + tsk->sched_class->set_curr_task(rq); task_rq_unlock(rq, tsk, &rf); }