From nobody Fri Oct 3 15:37:02 2025 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 3D37932C327 for ; Fri, 29 Aug 2025 15:48:34 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1756482514; cv=none; b=CNZKf0LwF9T7zK99sWoVPKM8RupM7y4Q1bC/sdEa+zco4d7/04wkoNKws09jnu49tthneEub96H/IfzBvUlMUQX4LRD1LfJkkH+91IQ6nzzS7gt8TWWuft+jcGhgUiJEdwXgOSd3/o7aer7cPFOBHy1+kEn1kxYKcUOp8rzaOBw= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1756482514; c=relaxed/simple; bh=tKKwBK9xX0xg3Dm/NJEdQ7r5p4nUDr3fqs7FMV7Y/xo=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=bBPY9125fZBl+/1fIfCGFzQGmToWQ7svMt3wZQHfY3plzHd3hkKrtur7N0WBW/g5Hy7aP19EMyPC1Gt61PITwxWrYYWyHsxtOAnFqX54vf2GgkDNvZA+oZmGhUx3i5Rar+pJzeMrGK53NBJnWnSTFVE5NL6vKdi8XWrob7eGx/A= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=JBCCVwqS; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="JBCCVwqS" Received: by smtp.kernel.org (Postfix) with ESMTPSA id C938AC4CEF5; Fri, 29 Aug 2025 15:48:31 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1756482514; bh=tKKwBK9xX0xg3Dm/NJEdQ7r5p4nUDr3fqs7FMV7Y/xo=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=JBCCVwqSjumn7XT4pVDMZEQLI5ogqSOLLqGspHQDWXhvD0P1ULdzN5pTeo2YYyls9 R1X0QNhPHFsw7zRULaD26WedF9faUpfaOdmDue3V+AlLjmpiuVjqW6ACLSQh0SNmbr dsb63Wt0czGmui5C6jv6RImZDkq7MhoITNU7+llg+qFQy+uOOTL0n6jNdOXsVzugv5 onzVLJ0B+qvls4RBWOQ5FmzyvIUvBjo6pcO4XanBU+cvUhEGyDwWroQcN/+opq93XB hNCXxaTRCVJ94BZun8eg+Rl+qFXPj1mkU88P5VcLTsoRIioeEpdrZpQDgXZhpkmvMe vvWARYaBRDQGQ== From: Frederic Weisbecker To: LKML Cc: Frederic Weisbecker , Andrew Morton , Marco Crivellari , Michal Hocko , Peter Zijlstra , Tejun Heo , Thomas Gleixner , Vlastimil Babka , Waiman Long , linux-mm@kvack.org Subject: [PATCH 05/33] mm: vmstat: Prepare to protect against concurrent isolated cpuset change Date: Fri, 29 Aug 2025 17:47:46 +0200 Message-ID: <20250829154814.47015-6-frederic@kernel.org> X-Mailer: git-send-email 2.51.0 In-Reply-To: <20250829154814.47015-1-frederic@kernel.org> References: <20250829154814.47015-1-frederic@kernel.org> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" The HK_TYPE_DOMAIN housekeeping cpumask will soon be made modifyable at runtime. In order to synchronize against vmstat workqueue to make sure that no asynchronous vmstat work is pending or executing on a newly made isolated CPU, target and queue a vmstat work under the same RCU read side critical section. Whenever housekeeping will update the HK_TYPE_DOMAIN cpumask, a vmstat workqueue flush will also be issued in a further change to make sure that no work remains pending after a CPU has been made isolated. Signed-off-by: Frederic Weisbecker --- mm/vmstat.c | 10 ++++++---- 1 file changed, 6 insertions(+), 4 deletions(-) diff --git a/mm/vmstat.c b/mm/vmstat.c index 71cd1ceba191..b90325ee49d3 100644 --- a/mm/vmstat.c +++ b/mm/vmstat.c @@ -2133,11 +2133,13 @@ static void vmstat_shepherd(struct work_struct *w) * infrastructure ever noticing. Skip regular flushing from vmstat_sheph= erd * for all isolated CPUs to avoid interference with the isolated workloa= d. */ - if (cpu_is_isolated(cpu)) - continue; + scoped_guard(rcu) { + if (cpu_is_isolated(cpu)) + continue; =20 - if (!delayed_work_pending(dw) && need_update(cpu)) - queue_delayed_work_on(cpu, mm_percpu_wq, dw, 0); + if (!delayed_work_pending(dw) && need_update(cpu)) + queue_delayed_work_on(cpu, mm_percpu_wq, dw, 0); + } =20 cond_resched(); } --=20 2.51.0