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Wed, 17 Dec 2025 14:36:31 -0800 (PST) Received: from localhost ([2603:7000:c01:2716:929a:4aff:fe16:c778]) by smtp.gmail.com with ESMTPSA id 6a1803df08f44-88c5dc728afsm4765666d6.12.2025.12.17.14.36.30 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 17 Dec 2025 14:36:30 -0800 (PST) Date: Wed, 17 Dec 2025 17:36:30 -0500 From: Johannes Weiner To: Qi Zheng Cc: hughd@google.com, mhocko@suse.com, roman.gushchin@linux.dev, shakeel.butt@linux.dev, muchun.song@linux.dev, david@kernel.org, lorenzo.stoakes@oracle.com, ziy@nvidia.com, harry.yoo@oracle.com, imran.f.khan@oracle.com, kamalesh.babulal@oracle.com, axelrasmussen@google.com, yuanchu@google.com, weixugc@google.com, chenridong@huaweicloud.com, mkoutny@suse.com, akpm@linux-foundation.org, hamzamahfooz@linux.microsoft.com, apais@linux.microsoft.com, lance.yang@linux.dev, linux-mm@kvack.org, linux-kernel@vger.kernel.org, cgroups@vger.kernel.org, Muchun Song , Qi Zheng Subject: Re: [PATCH v2 22/28] mm: workingset: prevent lruvec release in workingset_activation() Message-ID: References: <195a8cb47b90e48cd1ec6cb93bc33a8e794847f6.1765956026.git.zhengqi.arch@bytedance.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <195a8cb47b90e48cd1ec6cb93bc33a8e794847f6.1765956026.git.zhengqi.arch@bytedance.com> X-Rspamd-Queue-Id: 784EF1C0006 X-Stat-Signature: 8zh4chogjkscioymgafbo8w7p7iqcqpi X-Rspam-User: X-Rspamd-Server: rspam06 X-HE-Tag: 1766010992-741381 X-HE-Meta: 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 rlY3iKxE 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 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 Wed, Dec 17, 2025 at 03:27:46PM +0800, Qi Zheng wrote: > From: Muchun Song > > In the near future, a folio will no longer pin its corresponding > memory cgroup. So an lruvec returned by folio_lruvec() could be > released without the rcu read lock or a reference to its memory > cgroup. > > In the current patch, the rcu read lock is employed to safeguard > against the release of the lruvec in workingset_activation(). > > This serves as a preparatory measure for the reparenting of the > LRU pages. > > Signed-off-by: Muchun Song > Signed-off-by: Qi Zheng > Reviewed-by: Harry Yoo Acked-by: Johannes Weiner