linux-kernel - Re: [PATCH v2 17/28] mm: thp: prevent memory cgroup release in folio_split_queue_lock{

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Message-ID: <2e153b06-e541-41de-9b5d-7869dc2aba72@kernel.org>
Date: Thu, 18 Dec 2025 10:10:58 +0100
From: "David Hildenbrand (Red Hat)" <david@...nel.org>
To: Qi Zheng <qi.zheng@...ux.dev>, hannes@...xchg.org, hughd@...gle.com,
 mhocko@...e.com, roman.gushchin@...ux.dev, shakeel.butt@...ux.dev,
 muchun.song@...ux.dev, lorenzo.stoakes@...cle.com, ziy@...dia.com,
 harry.yoo@...cle.com, imran.f.khan@...cle.com, kamalesh.babulal@...cle.com,
 axelrasmussen@...gle.com, yuanchu@...gle.com, weixugc@...gle.com,
 chenridong@...weicloud.com, mkoutny@...e.com, akpm@...ux-foundation.org,
 hamzamahfooz@...ux.microsoft.com, apais@...ux.microsoft.com,
 lance.yang@...ux.dev
Cc: linux-mm@...ck.org, linux-kernel@...r.kernel.org,
 cgroups@...r.kernel.org, Qi Zheng <zhengqi.arch@...edance.com>
Subject: Re: [PATCH v2 17/28] mm: thp: prevent memory cgroup release in
 folio_split_queue_lock{_irqsave}()

On 12/17/25 08:27, Qi Zheng wrote:
> From: Qi Zheng <zhengqi.arch@...edance.com>
> 
> 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 <zhengqi.arch@...edance.com>
> Reviewed-by: Harry Yoo <harry.yoo@...cle.com>
> ---

Acked-by: David Hildenbrand (Red Hat) <david@...nel.org>

-- 
Cheers

David