From nobody Wed Dec 17 05:50:10 2025 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 0800F2253EF; Wed, 16 Apr 2025 19:16:40 +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=1744831003; cv=none; b=aT3/HwE0BmeKDq/P+x/8MsE3mFSR7is7L10vj0QXSpRpBQ42/Q8q38tpuST7vwptwJhZzNWqlqo9UgZi2omgzrwquQpqsuC2lAFheZY3Y3jrvx/rTYiTh72w4uRYhgFKKLlV1/gAIxVu1ek20hQMmtTsJENedzeUAyvoHio4fRU= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1744831003; c=relaxed/simple; bh=1Opu5mGMyyQZBNjrpMuTUB8AeXYckCct++E3AMnULe4=; h=Date:From:To:Subject:Cc:In-Reply-To:References:MIME-Version: Message-ID:Content-Type; b=G10lwj9McgIVOBO66uCjn7ReBbYozdhNzB3PoyGxGxhRneh+4ssjzUL6vtuhInpn2IukCk0YwG0ytD2puvVDVPdVPcDOaVwZTAz6E4WCjpleXeJLwRjZFyKQVVnMhnPZTkwf4u1x5lJaX/vBtuTTVT/7i+oqWHc2MZ38sldrdwo= 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=zsaoEceR; dkim=permerror (0-bit key) header.d=linutronix.de header.i=@linutronix.de header.b=4h3pQSvV; 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="zsaoEceR"; dkim=permerror (0-bit key) header.d=linutronix.de header.i=@linutronix.de header.b="4h3pQSvV" Date: Wed, 16 Apr 2025 19:16:38 -0000 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020; t=1744830999; 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=Aa1Wb5sPywK7zmdH30azMl4IYnnHkOT/puZig3RWRXM=; b=zsaoEceRnjP4dqkyG1wknNfMDd+IDNn9sPHAqbH9w1/5i6Ny5R559H/ksPwQW+He6Qb6zQ nfMRAmL/tG95ppL6Aca7q/gcXd0QPqzMs1GG27nGXozOJTfEiud86x3RCtKOTNPXUn4g4q Kk6m5vaPPfyoDbTjoh+vZ49wYTozKedPTSwEiSMYDttLvUwmb+siAxZu66l/xgL7ggowkV JVRkNDuXOv5/WAjF5Ma9OLvJhfglt2VBqZSyH+zAG+FV5WdZuMLsFpPKiyiRFF44uCrphY lzianACgcow4NuG5gk3UqTZFmycy5t2+0/xSOo7pOehjUvissiSk9v11gMmQtA== DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020e; t=1744830999; 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=Aa1Wb5sPywK7zmdH30azMl4IYnnHkOT/puZig3RWRXM=; b=4h3pQSvV9G1qFKwvzt7CeBAiVg4VbBV7OyQShRO/qcz6ECR1oPoDkF8FPcZSULCVjHseTs wJ58JtUv1sKHiECA== From: "tip-bot2 for K Prateek Nayak" 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: Use READ_ONCE() to read sg->asym_prefer_cpu Cc: K Prateek Nayak , "Peter Zijlstra (Intel)" , x86@kernel.org, linux-kernel@vger.kernel.org In-Reply-To: <20250409053446.23367-2-kprateek.nayak@amd.com> References: <20250409053446.23367-2-kprateek.nayak@amd.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Message-ID: <174483099840.31282.17802635645325940436.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: 872aa4de18889be63317a8c0f2de71a3a01e487c Gitweb: https://git.kernel.org/tip/872aa4de18889be63317a8c0f2de71a3a= 01e487c Author: K Prateek Nayak AuthorDate: Wed, 09 Apr 2025 05:34:43=20 Committer: Peter Zijlstra CommitterDate: Wed, 16 Apr 2025 21:09:11 +02:00 sched/fair: Use READ_ONCE() to read sg->asym_prefer_cpu Subsequent commits add the support to dynamically update the sched_group struct's "asym_prefer_cpu" member from a remote CPU. Use READ_ONCE() when reading the "sg->asym_prefer_cpu" to ensure load balancer always reads the latest value. Signed-off-by: K Prateek Nayak Signed-off-by: Peter Zijlstra (Intel) Link: https://lore.kernel.org/r/20250409053446.23367-2-kprateek.nayak@amd.c= om --- 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 0c19459..5e1bd9e 100644 --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -10251,7 +10251,7 @@ sched_group_asym(struct lb_env *env, struct sg_lb_s= tats *sgs, struct sched_group (sgs->group_weight - sgs->idle_cpus !=3D 1)) return false; =20 - return sched_asym(env->sd, env->dst_cpu, group->asym_prefer_cpu); + return sched_asym(env->sd, env->dst_cpu, READ_ONCE(group->asym_prefer_cpu= )); } =20 /* One group has more than one SMT CPU while the other group does not */ @@ -10488,7 +10488,8 @@ static bool update_sd_pick_busiest(struct lb_env *e= nv, =20 case group_asym_packing: /* Prefer to move from lowest priority CPU's work */ - return sched_asym_prefer(sds->busiest->asym_prefer_cpu, sg->asym_prefer_= cpu); + return sched_asym_prefer(READ_ONCE(sds->busiest->asym_prefer_cpu), + READ_ONCE(sg->asym_prefer_cpu)); =20 case group_misfit_task: /*