From nobody Mon May 25 00:09:07 2026 Received: from galois.linutronix.de (Galois.linutronix.de [193.142.43.55]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 2B5A43D666A; Wed, 20 May 2026 08:34:30 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=193.142.43.55 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1779266071; cv=none; b=LB3IB3l1M7kFcih89xZOoEFaN5KORLPAGnIfyMujPmZVF+J9mWdjyHrt0w224FyW7GGgpX/UcJzNQtYvROA/N8ol1EHEnfNp+cl33ZufZTylWspSUWY2R5GKaDANcjgQ0wIVEelEOY4V+bAnyuq1Rxlcf4fHAqG9gZSDjljjhVU= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1779266071; c=relaxed/simple; bh=P/uK9Fy27dk5D0eNzLJwfnuNAmFa6TDUDmIksEi9eNU=; h=Date:From:To:Subject:Cc:In-Reply-To:References:MIME-Version: Message-ID:Content-Type; b=qnCSNaBzcszvJKIRqis82lR1WnEzTHFruSyzRWeXnJWcBtlACfa1thGPE0LQ699MVCgZ7dEe3PmBawAdg3VgPA+bV9K0xLuCjtqQQnVVcOjhVssw5wJ20NKBwnSoJPLkArnwRF5Y+RQa9idHRSikr/VmvPk32tR1FiX1B41GWFU= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linutronix.de; spf=pass smtp.mailfrom=linutronix.de; dkim=pass (2048-bit key) header.d=linutronix.de header.i=@linutronix.de header.b=DVgrfLQ5; dkim=permerror (0-bit key) header.d=linutronix.de header.i=@linutronix.de header.b=0e8N71rn; arc=none smtp.client-ip=193.142.43.55 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linutronix.de Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linutronix.de Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=linutronix.de header.i=@linutronix.de header.b="DVgrfLQ5"; dkim=permerror (0-bit key) header.d=linutronix.de header.i=@linutronix.de header.b="0e8N71rn" Date: Wed, 20 May 2026 08:34:27 -0000 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020; t=1779266068; 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=mL+thuGWkLdoKobyetAkR/GhVA0GlRxJtXGai+viKHg=; b=DVgrfLQ5kZXkReqOrAzSk/hSMQsKVGNw22eiMmCCx8q9ZLD94tnJFSLVitJDkYa6Wre7S6 5aVFTL11X/kfEpWdBSso0g2zgDAu0D42IFLd9bQ0MgBITd7u3kxOSaOfQs4FHUR74TLJSv iAMmCLAnjQlO+MdVCDRpGBISx8S61z3KB0plLWhQEn9Z8D15sRRMmcKiKez7En6H45l664 hX97zzeIP7qE22XAiISWdiXMkvwlHpg9Ago+kt5378SqLft8U23itVs+EdQStlBPGiEtYl YsxNvSAwNxX8iZHhEYvlUCNEPCNLqZmvDpPTk/nGVUtjwvoDjVBvLNDkG33ihw== DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020e; t=1779266068; 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=mL+thuGWkLdoKobyetAkR/GhVA0GlRxJtXGai+viKHg=; b=0e8N71rnU93wXfClEZqSfVx5OdFJr/2obUompvZ4irRcOhxHaxwFtdb6hbg60BcgMJ0PLT RLKOUaY1IdDJ0cCg== From: "tip-bot2 for Chen Yu" Sender: tip-bot2@linutronix.de Reply-to: linux-kernel@vger.kernel.org To: linux-tip-commits@vger.kernel.org Subject: [tip: sched/core] sched/cache: Fix checking active load balance by only considering the CFS task Cc: Chen Yu , Tim Chen , "Peter Zijlstra (Intel)" , x86@kernel.org, linux-kernel@vger.kernel.org In-Reply-To: =?utf-8?q?=3Cf9161133cf040d286dca11344a112c5ef2a5253d=2E1778703?= =?utf-8?q?694=2Egit=2Etim=2Ec=2Echen=40linux=2Eintel=2Ecom=3E?= References: =?utf-8?q?=3Cf9161133cf040d286dca11344a112c5ef2a5253d=2E17787036?= =?utf-8?q?94=2Egit=2Etim=2Ec=2Echen=40linux=2Eintel=2Ecom=3E?= Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Message-ID: <177926606735.711.15011650880564110450.tip-bot2@tip-bot2> Robot-ID: Robot-Unsubscribe: Contact to get blacklisted from these emails Precedence: bulk Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable The following commit has been merged into the sched/core branch of tip: Commit-ID: d6b9afab44e23d537fb85ecf50330baaf9ec82e9 Gitweb: https://git.kernel.org/tip/d6b9afab44e23d537fb85ecf50330baaf= 9ec82e9 Author: Chen Yu AuthorDate: Wed, 13 May 2026 13:39:22 -07:00 Committer: Peter Zijlstra CommitterDate: Mon, 18 May 2026 21:33:17 +02:00 sched/cache: Fix checking active load balance by only considering the CFS t= ask The currently running task cur may not be a CFS task, such as an RT or Deadline task. For non-CFS tasks, the task_util(cur) utilization average is not maintained, so this might pass a stale or meaningless value to can_migrate_llc(). Check if the task is CFS before getting its task_util(). This bug was reported by sashiko. Fixes: 714059f79ff0 ("sched/cache: Handle moving single tasks to/from their= preferred LLC") Signed-off-by: Chen Yu Co-developed-by: Tim Chen Signed-off-by: Tim Chen Signed-off-by: Peter Zijlstra (Intel) Link: https://patch.msgid.link/f9161133cf040d286dca11344a112c5ef2a5253d.177= 8703694.git.tim.c.chen@linux.intel.com --- kernel/sched/fair.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c index 96c61ce..c249cae 100644 --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -10509,7 +10509,8 @@ alb_break_llc(struct lb_env *env) /* * All tasks prefer to stay on their current CPU. * Do not pull a task from its preferred CPU if: - * 1. It is the only task running there(not too imbalance); OR + * 1. It is the only task running and does not exceed + * imbalance allowance; OR * 2. Migrating it away from its preferred LLC would violate * the cache-aware scheduling policy. */ @@ -10522,7 +10523,7 @@ alb_break_llc(struct lb_env *env) return true; =20 cur =3D rcu_dereference_all(env->src_rq->curr); - if (cur) + if (cur && cur->sched_class =3D=3D &fair_sched_class) util =3D task_util(cur); =20 if (can_migrate_llc(env->src_cpu, env->dst_cpu,