Re: [PATCH RFC 21/28] mm: zswap: prevent lruvec release in zswap_folio_swapin()

[Nhat Pham]

On Mon, Apr 14, 2025 at 7:47 PM Muchun Song <songmuchun@xxxxxxxxxxxxx> wrote:
>
> 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 zswap_folio_swapin().
>
> This serves as a preparatory measure for the reparenting of the
> LRU pages.
>
> Signed-off-by: Muchun Song <songmuchun@xxxxxxxxxxxxx>

No objections from my end. AFAICT, wrapping this in rcu should not
break things, and we're in the slow path (disk swapping) anyway, so
should not be a problem.

Anyway:
Acked-by: Nhat Pham <nphamcs@xxxxxxxxx>