With the introduction of large folios for anonymous memory, we would
like to be able to split them when they have unmapped subpages, in order
to free those unused pages under memory pressure. So remove the
artificial requirement that the large folio needed to be at least
PMD-sized.

Signed-off-by: Ryan Roberts <ryan.roberts@arm.com>
---
 mm/rmap.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/mm/rmap.c b/mm/rmap.c
index ac1d93d43f2b..3d11c5fb6090 100644
--- a/mm/rmap.c
+++ b/mm/rmap.c
@@ -1567,7 +1567,7 @@ void page_remove_rmap(struct page *page, struct vm_area_struct *vma,
 		 * page of the folio is unmapped and at least one page
 		 * is still mapped.
 		 */
-		if (folio_test_pmd_mappable(folio) && folio_test_anon(folio))
+		if (folio_test_large(folio) && folio_test_anon(folio))
 			if (!compound || nr < nr_pmdmapped)
 				deferred_split_folio(folio);
 	}
-- 
2.25.1

On 6/27/23 01:14, Ryan Roberts wrote:
> With the introduction of large folios for anonymous memory, we would
> like to be able to split them when they have unmapped subpages, in order
> to free those unused pages under memory pressure. So remove the
> artificial requirement that the large folio needed to be at least
> PMD-sized.
> 
> Signed-off-by: Ryan Roberts <ryan.roberts@arm.com>
Reviewed-by: Yin Fengwei <fengwei.yin@intel.com>


Regards
Yin, Fengwei

> ---
>  mm/rmap.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/mm/rmap.c b/mm/rmap.c
> index ac1d93d43f2b..3d11c5fb6090 100644
> --- a/mm/rmap.c
> +++ b/mm/rmap.c
> @@ -1567,7 +1567,7 @@ void page_remove_rmap(struct page *page, struct vm_area_struct *vma,
>  		 * page of the folio is unmapped and at least one page
>  		 * is still mapped.
>  		 */
> -		if (folio_test_pmd_mappable(folio) && folio_test_anon(folio))
> +		if (folio_test_large(folio) && folio_test_anon(folio))
>  			if (!compound || nr < nr_pmdmapped)
>  				deferred_split_folio(folio);
>  	}

On Mon, Jun 26, 2023 at 11:15 AM Ryan Roberts <ryan.roberts@arm.com> wrote:
>
> With the introduction of large folios for anonymous memory, we would
> like to be able to split them when they have unmapped subpages, in order
> to free those unused pages under memory pressure. So remove the
> artificial requirement that the large folio needed to be at least
> PMD-sized.
>
> Signed-off-by: Ryan Roberts <ryan.roberts@arm.com>

Reviewed-by: Yu Zhao <yuzhao@google.com>