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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> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20260125224541.50226-5-frederic@kernel.org> X-Rspam-User: X-Rspamd-Server: rspam06 X-Rspamd-Queue-Id: A82DA1C0006 X-Stat-Signature: dntk891sxa8yj76fywr3crnbkxag9dar X-HE-Tag: 1769635137-929581 X-HE-Meta: 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 35af+0Wq OJBw9JCbcq0VeCEHvblFBF5pCnI2DQH14RDvph98UKltYTmWzJBByVEB6mGPdjqaEm/h8gNBxaoq35EYyU6VbFKp6+a6nZF/X1ZSJwSacugmPAkyzC3p77lB2lOR15IbKy8oETB4YKC2tE/ScW+bVQOH4TEXeO/Qbptt75tsSlyvDfDGm42bBBOEK4lG+09YifyfMlRXBmF/rOz0J347u0XCuE9cFv6HPnxkiy9iMF8K5nb2jOu9YFy5hwAOhnBqHFSTH2e8j7Q0yf3+rNMh+93EQcLQ20bMJAzbu3s6IMnziB4xQa+Oa/Ez3W1ye1NzVY38UZqhwwkEtsMFxb2hSMBorPH6nV3tzGFdFE0wi0CDDX2Jk3N/ifaOilHRvIu7wq16lPCQPtme3KV0w8ET/wTmsxHpTlLopLwUuQWGf32enZ66IMKYOV7WnpRwoEjFIAPf4 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: 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