From patchwork Tue May 26 18:54:09 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Greg KH X-Patchwork-Id: 225288 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=-9.8 required=3.0 tests=DKIMWL_WL_HIGH, DKIM_SIGNED, DKIM_VALID, HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH, MAILING_LIST_MULTI, SIGNED_OFF_BY, SPF_HELO_NONE, SPF_PASS, USER_AGENT_GIT autolearn=unavailable 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 1CBA6C433E0 for ; Tue, 26 May 2020 19:22:06 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id E729D20776 for ; Tue, 26 May 2020 19:22:05 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1590520925; bh=clFe/GQAHqSYLypx5ztprUXZNyS6D9G3lry4dPZ7X4g=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=XugIRIhHYrEnfDH+TPcYt8krclQsSdJSSzd4d81vwJ7UPtWT2OYpX6hIjRo0iRmOB lhCyJD4U0sVDxRbZXsSniD8XM59Mox6TQMfyWXimwwm91vBq0tZ+QRZeNL1FGzm22L gDQ4UpOF4G7Cw93moTb7MByb86LUdVVoL2XeGknk= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2403989AbgEZTKo (ORCPT ); Tue, 26 May 2020 15:10:44 -0400 Received: from mail.kernel.org ([198.145.29.99]:39912 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2391452AbgEZTKk (ORCPT ); Tue, 26 May 2020 15:10:40 -0400 Received: from localhost (83-86-89-107.cable.dynamic.v4.ziggo.nl [83.86.89.107]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 09DED20776; Tue, 26 May 2020 19:10:38 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1590520239; bh=clFe/GQAHqSYLypx5ztprUXZNyS6D9G3lry4dPZ7X4g=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=WscNLrP/fM/mbveq3uPcnByykBWcqspyX2QxhOoKdcYWimWumWBHaJMDV/Ow6aM9G C6KIx1+2JB+GQvPWDU1wz4xusueB577swrRC2fyvVzGjybSRIaBIeCCuOtGZpxq1ct ZwPwSeUW0fS8OQ3nNhKIjzk7a9aHs8bLPr9is+Ug= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Vincent Guittot , Phil Auld , "Peter Zijlstra (Intel)" , Dietmar Eggemann , Sasha Levin Subject: [PATCH 5.4 111/111] sched/fair: Fix enqueue_task_fair() warning some more Date: Tue, 26 May 2020 20:54:09 +0200 Message-Id: <20200526183943.413814507@linuxfoundation.org> X-Mailer: git-send-email 2.26.2 In-Reply-To: <20200526183932.245016380@linuxfoundation.org> References: <20200526183932.245016380@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Sender: stable-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Phil Auld [ Upstream commit b34cb07dde7c2346dec73d053ce926aeaa087303 ] 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. Fixes: fe61468b2cb ("sched/fair: Fix enqueue_task_fair warning") Suggested-by: Vincent Guittot Signed-off-by: Phil Auld Signed-off-by: Peter Zijlstra (Intel) Reviewed-by: Dietmar Eggemann Reviewed-by: Vincent Guittot Link: https://lkml.kernel.org/r/20200512135222.GC2201@lorien.usersys.redhat.com Signed-off-by: Sasha Levin --- kernel/sched/fair.c | 7 +++++++ 1 file changed, 7 insertions(+) diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c index 42cc3de24dcc..193b6ab74d7f 100644 --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -5254,6 +5254,13 @@ 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: