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 8D6D2C77B78 for ; Tue, 18 Apr 2023 12:54:06 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232296AbjDRMyF (ORCPT ); Tue, 18 Apr 2023 08:54:05 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:47718 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232294AbjDRMxy (ORCPT ); Tue, 18 Apr 2023 08:53:54 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [139.178.84.217]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 73D8E14475 for ; Tue, 18 Apr 2023 05:53:52 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id 541AE63479 for ; Tue, 18 Apr 2023 12:53:52 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 64FA5C433D2; Tue, 18 Apr 2023 12:53:51 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1681822431; bh=34OTwvMk60yMO/57En0O20FVOkCH4QLfS/CemPAJQ6g=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=PghS/MeJuxfnO6Xyd/UjqKJdS7onvQAOVh779WsGf6Af1hMG/wS3O1Q12pCxPaIVT Pkib32cCE4iOQYcglI0rIu43jes9Bj2jr+uj/ROlOAs9uFzC/Qz7LC12YuFxIm3tgW PsIg4HEyUr9+wNBBea4GzDn/GWF5OsiDC6XpzwO8= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Tingjia Cao , Vincent Guittot , "Peter Zijlstra (Intel)" , Sasha Levin Subject: [PATCH 6.2 132/139] sched/fair: Fix imbalance overflow Date: Tue, 18 Apr 2023 14:23:17 +0200 Message-Id: <20230418120318.847476461@linuxfoundation.org> X-Mailer: git-send-email 2.40.0 In-Reply-To: <20230418120313.725598495@linuxfoundation.org> References: <20230418120313.725598495@linuxfoundation.org> User-Agent: quilt/0.67 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Vincent Guittot [ Upstream commit 91dcf1e8068e9a8823e419a7a34ff4341275fb70 ] When local group is fully busy but its average load is above system load, computing the imbalance will overflow and local group is not the best target for pulling this load. Fixes: 0b0695f2b34a ("sched/fair: Rework load_balance()") Reported-by: Tingjia Cao Signed-off-by: Vincent Guittot Signed-off-by: Peter Zijlstra (Intel) Tested-by: Tingjia Cao Link: https://lore.kernel.org/lkml/CABcWv9_DAhVBOq2=W=2ypKE9dKM5s2DvoV8-U0+GDwwuKZ89jQ@mail.gmail.com/T/ Signed-off-by: Sasha Levin --- kernel/sched/fair.c | 10 ++++++++++ 1 file changed, 10 insertions(+) diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c index e046a2bff207b..661226e38835d 100644 --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -10123,6 +10123,16 @@ static inline void calculate_imbalance(struct lb_env *env, struct sd_lb_stats *s sds->avg_load = (sds->total_load * SCHED_CAPACITY_SCALE) / sds->total_capacity; + + /* + * If the local group is more loaded than the average system + * load, don't try to pull any tasks. + */ + if (local->avg_load >= sds->avg_load) { + env->imbalance = 0; + return; + } + } /* -- 2.39.2