Re: [PATCH 12/27] mm: refactor the ZONE_DEVICE handling in migrate_vma_pages

[Alistair Popple]

Reviewed-by: Alistair Popple <apop...@nvidia.com>

On Thursday, 10 February 2022 6:28:13 PM AEDT Christoph Hellwig wrote:
> Make the flow a little more clear and prepare for adding a new
> ZONE_DEVICE memory type.
> 
> Signed-off-by: Christoph Hellwig <h...@lst.de>
> ---
>  mm/migrate.c | 27 ++++++++++++---------------
>  1 file changed, 12 insertions(+), 15 deletions(-)
> 
> diff --git a/mm/migrate.c b/mm/migrate.c
> index 30ecd7223656c1..746e1230886ddb 100644
> --- a/mm/migrate.c
> +++ b/mm/migrate.c
> @@ -2788,24 +2788,21 @@ void migrate_vma_pages(struct migrate_vma *migrate)
>  
>               mapping = page_mapping(page);
>  
> -             if (is_zone_device_page(newpage)) {
> -                     if (is_device_private_page(newpage)) {
> -                             /*
> -                              * For now only support private anonymous when
> -                              * migrating to un-addressable device memory.
> -                              */
> -                             if (mapping) {
> -                                     migrate->src[i] &= ~MIGRATE_PFN_MIGRATE;
> -                                     continue;
> -                             }
> -                     } else {
> -                             /*
> -                              * Other types of ZONE_DEVICE page are not
> -                              * supported.
> -                              */
> +             if (is_device_private_page(newpage)) {
> +                     /*
> +                      * For now only support private anonymous when migrating
> +                      * to un-addressable device memory.
> +                      */
> +                     if (mapping) {
>                               migrate->src[i] &= ~MIGRATE_PFN_MIGRATE;
>                               continue;
>                       }
> +             } else if (is_zone_device_page(newpage)) {
> +                     /*
> +                      * Other types of ZONE_DEVICE page are not supported.
> +                      */
> +                     migrate->src[i] &= ~MIGRATE_PFN_MIGRATE;
> +                     continue;
>               }
>  
>               r = migrate_page(mapping, newpage, page, MIGRATE_SYNC_NO_COPY);
>