[RFC 02/11] mm/migrate_device: flags for selecting device private THP pages

[David Hildenbrand]

On 06.03.25 05:42, Balbir Singh wrote:
> Add flags to mark zone device migration pages.
> 
> MIGRATE_VMA_SELECT_COMPOUND will be used to select THP pages during
> migrate_vma_setup() and MIGRATE_PFN_COMPOUND will make migrating
> device pages as compound pages during device pfn migration.
> 
> Signed-off-by: Balbir Singh <balbirs at nvidia.com>
> ---
>   include/linux/migrate.h | 2 ++
>   1 file changed, 2 insertions(+)
> 
> diff --git a/include/linux/migrate.h b/include/linux/migrate.h
> index 61899ec7a9a3..b5e4f51e64c7 100644
> --- a/include/linux/migrate.h
> +++ b/include/linux/migrate.h
> @@ -167,6 +167,7 @@ static inline int migrate_misplaced_folio(struct folio *folio, int node)
>   #define MIGRATE_PFN_VALID	(1UL << 0)
>   #define MIGRATE_PFN_MIGRATE	(1UL << 1)
>   #define MIGRATE_PFN_WRITE	(1UL << 3)
> +#define MIGRATE_PFN_COMPOUND	(1UL << 4)
>   #define MIGRATE_PFN_SHIFT	6
>   
>   static inline struct page *migrate_pfn_to_page(unsigned long mpfn)
> @@ -185,6 +186,7 @@ enum migrate_vma_direction {
>   	MIGRATE_VMA_SELECT_SYSTEM = 1 << 0,
>   	MIGRATE_VMA_SELECT_DEVICE_PRIVATE = 1 << 1,
>   	MIGRATE_VMA_SELECT_DEVICE_COHERENT = 1 << 2,
> +	MIGRATE_VMA_SELECT_COMPOUND = 1 << 3,
>   };
>   
>   struct migrate_vma {

Squash that into the patch where it is actually used.

-- 
Cheers,

David / dhildenb