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=-8.5 required=3.0 tests=DKIMWL_WL_HIGH,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_SANE_1 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 E50AFC54E4A for ; Tue, 12 May 2020 13:52:35 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id BFD4B20730 for ; Tue, 12 May 2020 13:52:35 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="jIugJU/b" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730053AbgELNwf (ORCPT ); Tue, 12 May 2020 09:52:35 -0400 Received: from us-smtp-2.mimecast.com ([205.139.110.61]:43981 "EHLO us-smtp-delivery-1.mimecast.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1726891AbgELNwe (ORCPT ); Tue, 12 May 2020 09:52:34 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1589291553; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=Lk3pKSgX+YyRVM5jgz1CwnQ6zaZUpV/uZOU8kmdqEBc=; b=jIugJU/bhY5ck+91OaixjR/MrA2Gh7R9ndRLt7j6hUy9g024PK1t82/zO1QlXnkaBwXgO/ Y0b0xy5aeaK77wydbdwQBwF/LVz02Fmr82PnVvxb2Zl9NXyHySo6VWIZKUguF2+gfcFPk5 Wd+OSb7s1RWun0P+F5f0etzIpRr18Rg= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-224-16xwI3GENvyEQpd5-BpPWA-1; Tue, 12 May 2020 09:52:28 -0400 X-MC-Unique: 16xwI3GENvyEQpd5-BpPWA-1 Received: from smtp.corp.redhat.com (int-mx06.intmail.prod.int.phx2.redhat.com [10.5.11.16]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 8A67ABFC1; Tue, 12 May 2020 13:52:27 +0000 (UTC) Received: from lorien.usersys.redhat.com (ovpn-114-4.phx2.redhat.com [10.3.114.4]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 227FC5C1BB; Tue, 12 May 2020 13:52:24 +0000 (UTC) Date: Tue, 12 May 2020 09:52:22 -0400 From: Phil Auld To: peterz@infradead.org Cc: linux-kernel@vger.kernel.org, mingo@kernel.org, vincent.guittot@linaro.org, juri.lelli@redhat.com, zohooouoto@zoho.com.cn, dietmar.eggemann@arm.com Subject: Re: [PATCH v3] sched/fair: Fix enqueue_task_fair warning some more Message-ID: <20200512135222.GC2201@lorien.usersys.redhat.com> References: <20200506141821.GA9773@lorien.usersys.redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200506141821.GA9773@lorien.usersys.redhat.com> User-Agent: Mutt/1.12.1 (2019-06-15) X-Scanned-By: MIMEDefang 2.79 on 10.5.11.16 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org sched/fair: Fix enqueue_task_fair warning some more The recent patch, fe61468b2cb (sched/fair: Fix enqueue_task_fair warning) did not fully resolve the issues with the rq->tmp_alone_branch != &rq->leaf_cfs_rq_list warning in enqueue_task_fair. There is a case where the first for_each_sched_entity loop exits due to on_rq, having incompletely updated the list. In this case the second for_each_sched_entity loop can further modify se. The later code to fix up the list management fails to do what is needed because se does not point to the sched_entity which broke out of the first loop. The list is not fixed up because the throttled parent was already added back to the list by a task enqueue in a parallel child hierarchy. Address this by calling list_add_leaf_cfs_rq if there are throttled parents while doing the second for_each_sched_entity loop. v3: clean up commit message and add fixes and review tags. Suggested-by: Vincent Guittot Signed-off-by: Phil Auld Cc: Peter Zijlstra (Intel) Cc: Vincent Guittot Cc: Ingo Molnar Cc: Juri Lelli Reviewed-by: Vincent Guittot Reviewed-by: Dietmar Eggemann Fixes: fe61468b2cb (sched/fair: Fix enqueue_task_fair warning) --- kernel/sched/fair.c | 7 +++++++ 1 file changed, 7 insertions(+) diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c index 02f323b85b6d..c6d57c334d51 100644 --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -5479,6 +5479,13 @@ enqueue_task_fair(struct rq *rq, struct task_struct *p, int flags) /* end evaluation on encountering a throttled cfs_rq */ if (cfs_rq_throttled(cfs_rq)) goto enqueue_throttle; + + /* + * One parent has been throttled and cfs_rq removed from the + * list. Add it back to not break the leaf list. + */ + if (throttled_hierarchy(cfs_rq)) + list_add_leaf_cfs_rq(cfs_rq); } enqueue_throttle: -- 2.18.0 --