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From: Muchun Song In-Reply-To: <061b1110696ba51e454ad0f7549603ec92cdb5ea.1768389889.git.zhengqi.arch@bytedance.com> Date: Fri, 16 Jan 2026 17:15:36 +0800 Cc: hannes@cmpxchg.org, hughd@google.com, mhocko@suse.com, roman.gushchin@linux.dev, shakeel.butt@linux.dev, david@kernel.org, lorenzo.stoakes@oracle.com, ziy@nvidia.com, harry.yoo@oracle.com, yosry.ahmed@linux.dev, 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, Qi Zheng Content-Transfer-Encoding: 7bit Message-Id: <394C2721-72AF-44AE-9953-C7C6DCFC8038@linux.dev> References: <061b1110696ba51e454ad0f7549603ec92cdb5ea.1768389889.git.zhengqi.arch@bytedance.com> To: Qi Zheng X-Migadu-Flow: FLOW_OUT X-Rspamd-Server: rspam12 X-Rspamd-Queue-Id: 74D33140008 X-Stat-Signature: pbno1ib9r3w1693e5hfccd4f5m6hgd5k X-Rspam-User: X-HE-Tag: 1768554991-253464 X-HE-Meta: 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 QbVFIq4f oTMnmLIBS/sn6sBzFJ1f6fN0XQhSkARHYQFAM34fFwebvQKizxIe16Yd7R5IzYB63UMWKAOwVAU6yB6PuqHJNKXeVZEdKUdfSkXyjyJ102eRAgLy2mvTDpuBoo0q04vSrs82E5SKqcGZHWcjolQBWMDdmtWWPyET3SJCKd98R5wSJpC0FloJULuPGP8zLEIhHHd/SEuxC0Rtes6m5Y5v7XnQ25qi+lJZ73suP9w3BLO4bH+EXkxoetWdzZWHLFTJFfuoIYAdsa1Xnddw/Ync9CCQrmpVst6BnFlMEfdzNavEAciXEbTPE8J6PERYXT4JyH2XlbLEla0YZLNZbgNhnM1g2C/KmDlum1UGnNE6b2HywsjNikRS1PXLtE8885qn5RKGxuLYemSK/DomcrksSNxZS14dkUG+Wt7cJIbkeWqfEs40sLfObwX7LqQ== 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 Jan 14, 2026, at 19:32, Qi Zheng wrote: > > From: Qi Zheng > > In the near future, a folio will no longer pin its corresponding memory > cgroup. To ensure safety, it will only be appropriate to hold the rcu read > lock or acquire a reference to the memory cgroup returned by > folio_memcg(), thereby preventing it from being released. > > In the current patch, the rcu read lock is employed to safeguard against > the release of the memory cgroup in folio_split_queue_lock{_irqsave}(). > > Signed-off-by: Qi Zheng > Reviewed-by: Harry Yoo > Acked-by: Johannes Weiner > Acked-by: Shakeel Butt > Acked-by: David Hildenbrand (Red Hat) Acked-by: Muchun Song