Re: [PATCH 2/4] drm/pagemap: Unlock and put folios when possible

[Matthew Brost <matthew.brost@intel.com>]

On Tue, Dec 16, 2025 at 09:10:12PM +0100, 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.
> 
> Suggested-by: Matthew Brost <matthew.brost@intel.com>
> Signed-off-by: Francois Dugast <francois.dugast@intel.com>

Reviewed-by: Matthew Brost <matthew.brost@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 37d7cfbbb3e8..491de9275add 100644
> --- a/drivers/gpu/drm/drm_pagemap.c
> +++ b/drivers/gpu/drm/drm_pagemap.c
> @@ -149,15 +149,15 @@ 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);
>  }
>  
>  /**
> @@ -172,15 +172,23 @@ 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);
>  	}
>  }
>  
> -- 
> 2.43.0
>