Re: [PATCH v4] mm: introduce a new page type for page pool in page type

[Mike Rapoport <rppt@kernel.org>]

On Tue, Feb 24, 2026 at 02:13:47PM +0900, Byungchul Park wrote:
> Currently, the condition 'page->pp_magic == PP_SIGNATURE' is used to
> determine if a page belongs to a page pool.  However, with the planned
> removal of @pp_magic, we should instead leverage the page_type in struct
> page, such as PGTY_netpp, for this purpose.
> 
> Introduce and use the page type APIs e.g. PageNetpp(), __SetPageNetpp(),
> and __ClearPageNetpp() instead, and remove the existing APIs accessing
> @pp_magic e.g. page_pool_page_is_pp(), netmem_or_pp_magic(), and
> netmem_clear_pp_magic().
> 
> Plus, add @page_type to struct net_iov at the same offset as struct page
> so as to use the page_type APIs for struct net_iov as well.  While at it,
> reorder @type and @owner in struct net_iov to avoid a hole and
> increasing the struct size.
> 
> This work was inspired by the following link:
> 
>   https://lore.kernel.org/all/582f41c0-2742-4400-9c81-0d46bf4e8314@gmail.com/
> 
> While at it, move the sanity check for page pool to on the free path.
> 
> Suggested-by: David Hildenbrand <david@redhat.com>
> Co-developed-by: Pavel Begunkov <asml.silence@gmail.com>
> Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
> Signed-off-by: Byungchul Park <byungchul@sk.com>
> Acked-by: David Hildenbrand <david@redhat.com>
> Acked-by: Zi Yan <ziy@nvidia.com>
> Acked-by: Vlastimil Babka <vbabka@suse.cz>
> Reviewed-by: Toke Høiland-Jørgensen <toke@redhat.com>

Acked-by: Mike Rapoport (Microsoft) <rppt@kernel.org>

-- 
Sincerely yours,
Mike.