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From: Shakeel Butt To: Qi Zheng Cc: hannes@cmpxchg.org, hughd@google.com, mhocko@suse.com, roman.gushchin@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: <3eiitl5ghm3dvueb73oedjbrungpidx42fae5t26gzvpsxgrh3@aeormwrvvkrr> 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-Migadu-Flow: FLOW_OUT X-Rspamd-Server: rspam08 X-Rspamd-Queue-Id: BEABC18000B X-Stat-Signature: g6cxtk6n1meemg3f1fd6jrtd7fmtzmkj X-Rspam-User: X-HE-Tag: 1766193961-921450 X-HE-Meta: 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 YUiO5TVH DAaxizwFJhWoWYaEwtxc5XoDzmHi+4jelxA7HxUNmfA8xqub/8BUj2mwWOl+RHFPl5y3+3aU9d+S5kuKZjXZr2HTT14IiyOgKdjqwhvMKUxpQ96ZMMvKW2HQCL4TCLcgVXoznNew+RyHZjIf6vtLN9I6bKu4BG2R44R9oHrwkZID2YPntjSpNDPMCmjKoE4fRfdbvG43C2qOgSjCBnbuQW2UaLMC0KLDDZq7ACdKeLY09ic/ebzpBanh/PU5Rj3TDkocOZIn69EiEqAJqsSmSJsn5j+gw/pD3/PqQbmbycCcadFQ= 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: Shakeel Butt