Re: [PATCH v5 2/5] drm/pagemap: Unlock and put folios when possible

Balbir Singh
2026-01-15T02:41:24Z

On 1/15/26 06:19, Francois Dugast wrote:
> If the page is part of a folio, unlock and put the whole folio at once
> instead of individual pages one after the other. This will reduce the
> amount of operations once device THP are in use.
>
> Cc: Andrew Morton <akpm@linux-foundation.org>
> Cc: David Hildenbrand <david@kernel.org>
> Cc: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
> Cc: Liam R. Howlett <Liam.Howlett@oracle.com>
> Cc: Vlastimil Babka <vbabka@suse.cz>
> Cc: Mike Rapoport <rppt@kernel.org>
> Cc: Suren Baghdasaryan <surenb@google.com>
> Cc: Michal Hocko <mhocko@suse.com>
> Cc: Zi Yan <ziy@nvidia.com>
> Cc: Alistair Popple <apopple@nvidia.com>
> Cc: Balbir Singh <balbirs@nvidia.com>
> Cc: linux-mm@kvack.org
> Suggested-by: Matthew Brost <matthew.brost@intel.com>
> Reviewed-by: Matthew Brost <matthew.brost@intel.com>
> Signed-off-by: Francois Dugast <francois.dugast@intel.com>
> ---
> drivers/gpu/drm/drm_pagemap.c | 26 +++++++++++++++++---------
> 1 file changed, 17 insertions(+), 9 deletions(-)
>
> diff --git a/drivers/gpu/drm/drm_pagemap.c b/drivers/gpu/drm/drm_pagemap.c
> index c497726b0147..b31090b8e97c 100644
> --- a/drivers/gpu/drm/drm_pagemap.c
> +++ b/drivers/gpu/drm/drm_pagemap.c
> @@ -154,15 +154,15 @@ static void drm_pagemap_zdd_put(struct drm_pagemap_zdd *zdd)
> }
>
> /**
> - * drm_pagemap_migration_unlock_put_page() - Put a migration page
> - * @page: Pointer to the page to put
> + * drm_pagemap_migration_unlock_put_folio() - Put a migration folio
> + * @folio: Pointer to the folio to put
> *
> - * This function unlocks and puts a page.
> + * This function unlocks and puts a folio.
> */
> -static void drm_pagemap_migration_unlock_put_page(struct page *page)
> +static void drm_pagemap_migration_unlock_put_folio(struct folio *folio)
> {
> - unlock_page(page);
> - put_page(page);
> + folio_unlock(folio);
> + folio_put(folio);
> }
>
> /**
> @@ -177,15 +177,23 @@ static void drm_pagemap_migration_unlock_put_pages(unsigned long npages,
> {
> unsigned long i;
>
> - for (i = 0; i < npages; ++i) {
> + for (i = 0; i < npages;) {
> struct page *page;
> + struct folio *folio;
> + unsigned int order = 0;
>
> if (!migrate_pfn[i])
> - continue;
> + goto next;
>
> page = migrate_pfn_to_page(migrate_pfn[i]);
> - drm_pagemap_migration_unlock_put_page(page);
> + folio = page_folio(page);
> + order = folio_order(folio);
> +
> + drm_pagemap_migration_unlock_put_folio(folio);
> migrate_pfn[i] = 0;
> +
> +next:
> + i += NR_PAGES(order);

Is this just a wrapper on top of folio_nr_pages()?

> }
> }
>

Reviewed-by: Balbir Singh <balbirs@nvidia.com>