From nobody Fri Apr 3 05:19:03 2026 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 2E2ACECAAA1 for ; Thu, 15 Sep 2022 14:24:41 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229847AbiIOOYj (ORCPT ); Thu, 15 Sep 2022 10:24:39 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:33166 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230202AbiIOOYU (ORCPT ); Thu, 15 Sep 2022 10:24:20 -0400 Received: from galois.linutronix.de (Galois.linutronix.de [IPv6:2a0a:51c0:0:12e:550::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 150749D660; Thu, 15 Sep 2022 07:24:14 -0700 (PDT) Date: Thu, 15 Sep 2022 14:24:12 -0000 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020; t=1663251853; h=from:from:sender:sender:reply-to:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=sYLTbk1pAEcT6Czyezu6IS/EnqxfSbnZwJ7B0GvN8Rs=; b=2p9hRwEJJkJVUsqcQ53sUbQ+Tp0wGWVgjuR2Nc8kTqTe1IjFJ0eTGZrj2jc8yXjOdi/Yjb WS7NTiAIRstmhR+FyTEu0TLl86DM7RtPj4AzvQPVh09ddDuQUy4Ay0fXAy83hPWdwnv79F JTYji7Hb1t8wPLD5XgrSPclfTnMRnp4bPGbQQhOhZWt91AKiw6n3fVtFKRk9jdRpRMnL21 gh0/uMOJeIJsj+hkH3eN8DdcENhNWjs3e+lyLsV5QC2p1sW+NjDMgqr8Gv0rbWHJCqHnnG TtlcyHEKeBMrp86cF8C6FvZbm5I7exyAkRNFJr8S5v0iecv3GIoIs6YRX/ME5w== DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020e; t=1663251853; h=from:from:sender:sender:reply-to:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=sYLTbk1pAEcT6Czyezu6IS/EnqxfSbnZwJ7B0GvN8Rs=; b=Gr5sWrGNBoZiUz/GLzkLeWtK77nps+41kZk+AV0s4diYwXFRu1i3fR5lEt/GQmnMXRzu0Q 4/ZdrnfO4wM8lUCw== From: "tip-bot2 for Vincent Guittot" Sender: tip-bot2@linutronix.de Reply-to: linux-kernel@vger.kernel.org To: linux-tip-commits@vger.kernel.org Subject: [tip: sched/core] sched/fair: Make sure to try to detach at least one movable task Cc: Vincent Guittot , "Peter Zijlstra (Intel)" , x86@kernel.org, linux-kernel@vger.kernel.org In-Reply-To: <20220825122726.20819-2-vincent.guittot@linaro.org> References: <20220825122726.20819-2-vincent.guittot@linaro.org> MIME-Version: 1.0 Message-ID: <166325185230.401.16508642684014916444.tip-bot2@tip-bot2> Robot-ID: Robot-Unsubscribe: Contact to get blacklisted from these emails Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org The following commit has been merged into the sched/core branch of tip: Commit-ID: b0defa7ae03ecf91b8bfd10ede430cff12fcbd06 Gitweb: https://git.kernel.org/tip/b0defa7ae03ecf91b8bfd10ede430cff1= 2fcbd06 Author: Vincent Guittot AuthorDate: Thu, 25 Aug 2022 14:27:23 +02:00 Committer: Peter Zijlstra CommitterDate: Thu, 15 Sep 2022 16:13:51 +02:00 sched/fair: Make sure to try to detach at least one movable task During load balance, we try at most env->loop_max time to move a task. But it can happen that the loop_max LRU tasks (ie tail of the cfs_tasks list) can't be moved to dst_cpu because of affinity. In this case, loop in the list until we found at least one. The maximum of detached tasks remained the same as before. Signed-off-by: Vincent Guittot Signed-off-by: Peter Zijlstra (Intel) Link: https://lkml.kernel.org/r/20220825122726.20819-2-vincent.guittot@lina= ro.org --- kernel/sched/fair.c | 12 +++++++++--- 1 file changed, 9 insertions(+), 3 deletions(-) diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c index 4e5b171..dae3bfa 100644 --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -8049,8 +8049,12 @@ static int detach_tasks(struct lb_env *env) p =3D list_last_entry(tasks, struct task_struct, se.group_node); =20 env->loop++; - /* We've more or less seen every task there is, call it quits */ - if (env->loop > env->loop_max) + /* + * We've more or less seen every task there is, call it quits + * unless we haven't found any movable task yet. + */ + if (env->loop > env->loop_max && + !(env->flags & LBF_ALL_PINNED)) break; =20 /* take a breather every nr_migrate tasks */ @@ -10179,7 +10183,9 @@ more_balance: =20 if (env.flags & LBF_NEED_BREAK) { env.flags &=3D ~LBF_NEED_BREAK; - goto more_balance; + /* Stop if we tried all running tasks */ + if (env.loop < busiest->nr_running) + goto more_balance; } =20 /*