Re: [PATCH v1 12/26] mm: migrate: prevent memory cgroup release in folio_migrate_mapping()

Harry Yoo
2025-11-19T10:00:58Z

On Tue, Oct 28, 2025 at 09:58:25PM +0800, Qi Zheng wrote:
> From: Muchun Song <songmuchun@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 folio_migrate_mapping().
>
> This serves as a preparatory measure for the reparenting of the
> LRU pages.
>
> Signed-off-by: Muchun Song <songmuchun@bytedance.com>
> Signed-off-by: Qi Zheng <zhengqi.arch@bytedance.com>
> ---

Looks good to me,
Reviewed-by: Harry Yoo <harry.yoo@oracle.com>

--
Cheers,
Harry / Hyeonggon