From mboxrd@z Thu Jan 1 00:00:00 1970 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 87EC031196F; Tue, 27 Jan 2026 12:45:09 +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=1769517909; cv=none; b=lSaDGX+vfHBP5n5Pq9+3wdY0jj5gTkKrSdKnBkT22eVxosjmYrX747N1J7hONcm3HhopVBxy7dX9lO5IphbQi8vKDCxRGS2kGEOFR47iXNsa3WtxMff+RQ2/GrM50PS8I7qDjhc5VB3tf4UrmZKNIG098uVx9EoPgS7MEXLcIDw= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1769517909; c=relaxed/simple; bh=ofe10jGZoPAqJE9FQOSEtDptbVaYpx/CGbuhre/HHNI=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=sY28Rn/e1mXjEU2LhmjdcPJH81QrLEnSpQwoivZDBNh1UzjSHjL5Mgvd9+5s/Pm5peJ4cEO5ywkCytNg0Gw0v/+rEhP/gncGyNmEfbfOV3rrRcmC+KF8P6h2NsNi5Ovd0q3QMmrvB/uZsq1ItPJe7UiUWBi/thOktr2/LO/ICjY= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=ZqptSIfL; 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="ZqptSIfL" Received: by smtp.kernel.org (Postfix) with ESMTPSA id AACFEC116C6; Tue, 27 Jan 2026 12:45:08 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1769517909; bh=ofe10jGZoPAqJE9FQOSEtDptbVaYpx/CGbuhre/HHNI=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=ZqptSIfLm29TLryUzU52GQpI9Y5j/egT2jG8/oQhaPPiFuy2brZcTTjX8upURbbwK O2avXbgCiqu9oze4K2pbYNChHpLvtm1Jz9vMFgmPsvm1Qg+qCGw0xz/oS/xiGbbAQa SpjcCq8AzzyIPMh00tl2Kgj9nT4Pwz/av8vbzs9TI8IvS0TbBOA5TPk5EJhldEKCd8 z9JwUU8X8St7FkUL33asPHS0EmzbQdBqKLrg7pOsDN/QpZKsgStUPPRJtFFRc43nWE 6CsKod/Uczqk8wBl9Y2/65PFXOSK8XPZjs8cgK1siNQjv5//Rrl9afMnIDi/jt4EBR gt2lbSbmoncAQ== Date: Tue, 27 Jan 2026 13:45:06 +0100 From: Frederic Weisbecker To: Michal Hocko Cc: LKML , Michal =?iso-8859-1?Q?Koutn=FD?= , Andrew Morton , Bjorn Helgaas , Catalin Marinas , Chen Ridong , Danilo Krummrich , "David S . Miller" , Eric Dumazet , Gabriele Monaco , Greg Kroah-Hartman , Ingo Molnar , Jakub Kicinski , Jens Axboe , Johannes Weiner , Lai Jiangshan , Marco Crivellari , Muchun Song , Paolo Abeni , Peter Zijlstra , Phil Auld , "Rafael J . Wysocki" , Roman Gushchin , Shakeel Butt , Simon Horman , Tejun Heo , Thomas Gleixner , Vlastimil Babka , Waiman Long , Will Deacon , cgroups@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-block@vger.kernel.org, linux-mm@kvack.org, linux-pci@vger.kernel.org, netdev@vger.kernel.org Subject: Re: [PATCH 03/33] memcg: Prepare to protect against concurrent isolated cpuset change Message-ID: References: <20260125224541.50226-1-frederic@kernel.org> <20260125224541.50226-4-frederic@kernel.org> Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: Le Mon, Jan 26, 2026 at 05:41:38PM +0100, Michal Hocko a écrit : > On Sun 25-01-26 23:45:10, Frederic Weisbecker wrote: > > The HK_TYPE_DOMAIN housekeeping cpumask will soon be made modifiable at > > runtime. In order to synchronize against memcg workqueue to make sure > > that no asynchronous draining is pending or executing on a newly made > > isolated CPU, target and queue a drain work under the same RCU critical > > section. > > > > Whenever housekeeping will update the HK_TYPE_DOMAIN cpumask, a memcg > > 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/memcontrol.c | 21 +++++++++++++++++---- > > 1 file changed, 17 insertions(+), 4 deletions(-) > > > > diff --git a/mm/memcontrol.c b/mm/memcontrol.c > > index be810c1fbfc3..2289a0299331 100644 > > --- a/mm/memcontrol.c > > +++ b/mm/memcontrol.c > > @@ -2003,6 +2003,19 @@ static bool is_memcg_drain_needed(struct memcg_stock_pcp *stock, > > return flush; > > } > > > > +static void schedule_drain_work(int cpu, struct work_struct *work) > > +{ > > + /* > > + * Protect housekeeping cpumask read and work enqueue together > > + * in the same RCU critical section so that later cpuset isolated > > + * partition update only need to wait for an RCU GP and flush the > > + * pending work on newly isolated CPUs. > > + */ > > + guard(rcu)(); > > + if (!cpu_is_isolated(cpu)) > > + schedule_work_on(cpu, work); > > Shouldn't this in the guarded rcu section? This is what guard(rcu)() does, right? Or am I missing something? Thanks. -- Frederic Weisbecker SUSE Labs