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Subject: Re: [PATCH v3 18/30] mm: zswap: prevent memory cgroup release in
 zswap_compress()
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From: Muchun Song <muchun.song@linux.dev>
In-Reply-To: <592f65bbe05587c01a2718443a70e639cc611f3d.1768389889.git.zhengqi.arch@bytedance.com>
Date: Fri, 16 Jan 2026 17:18:16 +0800
Cc: hannes@cmpxchg.org,
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 roman.gushchin@linux.dev,
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 Qi Zheng <zhengqi.arch@bytedance.com>
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References: <cover.1768389889.git.zhengqi.arch@bytedance.com>
 <592f65bbe05587c01a2718443a70e639cc611f3d.1768389889.git.zhengqi.arch@bytedance.com>
To: Qi Zheng <qi.zheng@linux.dev>
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> On Jan 14, 2026, at 19:32, Qi Zheng <qi.zheng@linux.dev> wrote:
> 
> From: Qi Zheng <zhengqi.arch@bytedance.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 zswap_compress().
> 
> Signed-off-by: Qi Zheng <zhengqi.arch@bytedance.com>
> Acked-by: Johannes Weiner <hannes@cmpxchg.org>
> Acked-by: Shakeel Butt <shakeel.butt@linux.dev>

Acked-by: Muchun Song <muchun.song@linux.dev>