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[109.81.26.156]) by smtp.gmail.com with ESMTPSA id 5b1f17b1804b1-4806d78cb6csm3510525e9.2.2026.01.28.13.18.55 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 28 Jan 2026 13:18:55 -0800 (PST) Date: Wed, 28 Jan 2026 22:18:54 +0100 From: Michal Hocko To: Frederic Weisbecker 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 04/33] mm: vmstat: Prepare to protect against concurrent isolated cpuset change Message-ID: References: <20260125224541.50226-1-frederic@kernel.org> <20260125224541.50226-5-frederic@kernel.org> Precedence: bulk X-Mailing-List: linux-block@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20260125224541.50226-5-frederic@kernel.org> On Sun 25-01-26 23:45:11, Frederic Weisbecker wrote: > The HK_TYPE_DOMAIN housekeeping cpumask will soon be made modifiable 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 Acked-by: Michal Hocko Thanks! > --- > mm/vmstat.c | 10 ++++++---- > 1 file changed, 6 insertions(+), 4 deletions(-) > > diff --git a/mm/vmstat.c b/mm/vmstat.c > index 65de88cdf40e..ed19c0d42de6 100644 > --- a/mm/vmstat.c > +++ b/mm/vmstat.c > @@ -2144,11 +2144,13 @@ static void vmstat_shepherd(struct work_struct *w) > * infrastructure ever noticing. Skip regular flushing from vmstat_shepherd > * for all isolated CPUs to avoid interference with the isolated workload. > */ > - if (cpu_is_isolated(cpu)) > - continue; > + scoped_guard(rcu) { > + if (cpu_is_isolated(cpu)) > + continue; > > - 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); > + } > > cond_resched(); > } > -- > 2.51.1 > -- Michal Hocko SUSE Labs