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a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1750433010; bh=pRfQHigt/JUjt7Ua7aNjiQ8K2ZKMtGoq+XwcBsIjDcA=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=LMOxLQew+8SD0QmKJR5IFcYSv9Ibc0MeI6Xv2VKk19HsGigM1Qm9amtVtp5hj2fQ0 pEslfbicQSZ8ekF5i02k2hUdg7d/IxxuoWmadNan3ALw9niHU6ev9IS9Jh+X6DX9I7 c9cZBpnrwRyJNmmX2hjp0ka9mnnRCWkK2HnlJp4QNZzl3ut8tlFbRu5Zd+UsKaoc7+ 0jazqNeXyXTyz9G3bIEjDfJ0BolBqWY4EhiqHoMS9Ix/cI8P2zxdt2rdvgywUPAZId kkX08YtsIcBB4EnRPi2j1vEDOpAm1DJV2lK7q2DCJUq9clpBDPKsRT0Kh4wAOx2Cb+ qkiMFu2Px64ZQ== 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 06/27] mm: vmstat: Prepare to protect against concurrent isolated cpuset change Date: Fri, 20 Jun 2025 17:22:47 +0200 Message-ID: <20250620152308.27492-7-frederic@kernel.org> X-Mailer: git-send-email 2.48.1 In-Reply-To: <20250620152308.27492-1-frederic@kernel.org> References: <20250620152308.27492-1-frederic@kernel.org> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Rspam-User: X-Stat-Signature: mu8gqjgbfw9enqbi3qke9wjx84odt6kd X-Rspamd-Queue-Id: 8193B100009 X-Rspamd-Server: rspam02 X-HE-Tag: 1750433011-553095 X-HE-Meta: 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 /+w7tP1W 0X/kpmm+AOOJiGREChYk+MWjcJKK5sGxjVLwjA6A6k3a7mr0r0lD5EN6jp++rDTtdBVqttBFjbTOdJBntyCAPu9dIwv4pUCtKDT64iy6xeJaOKvYS+iyhcc6eSnt9GwV89c4hmOsl9HV5pmScJtoXcnBX73A2Rxd6UeLbJdezRoKWPQm0fWwHJxvnQFAxzHMyT5WnFcGck70kcmRvKafCwTQuDGwgy9nHDO27yGlAHMcVDoo= 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: 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, read-lock the housekeeping rwsem lock while targeting and queueing a vmstat work. 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 had 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 429ae5339bfe..53123675fe31 100644 --- a/mm/vmstat.c +++ b/mm/vmstat.c @@ -2115,11 +2115,13 @@ 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(housekeeping) { + 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(); } -- 2.48.1