Re: [PATCH 1/2] mm: decrement MTHP_STAT_NR_ANON in free_zone_device_folio()

[Zi Yan]

On Thu Jul 2, 2026 at 1:25 PM EDT, Nico Pache wrote:
> When a zone device folio is mapped as anonymous, folio_add_new_anon_rmap()
> increments MTHP_STAT_NR_ANON. The corresponding decrement lives in
> __free_pages_prepare() in page_alloc.c, but zone device folios are freed
> via free_zone_device_folio() which never calls __free_pages_prepare().
> This causes nr_anon to remain permanently elevated after zone device
> folios are freed.
>
> Add the missing mod_mthp_stat() decrement to free_zone_device_folio()
> so that the counter is properly balanced.
>
> Fixes: 5d65c8d758f2 ("mm: count the number of anonymous THPs per size")
> Co-developed-by: David Hildenbrand <david@xxxxxxxxxx>
> Signed-off-by: David Hildenbrand <david@xxxxxxxxxx>
> Signed-off-by: Nico Pache <npache@xxxxxxxxxx>
> ---
>  mm/memremap.c | 1 +
>  1 file changed, 1 insertion(+)
>
LGTM.

Reviewed-by: Zi Yan <ziy@xxxxxxxxxx>


-- 
Best Regards,
Yan, Zi