From: Vernon Yang <yanglincheng@kylinos.cn>

Add folio_test_lazyfree() function to identify lazy-free folios to improve
code readability.

Signed-off-by: Vernon Yang <yanglincheng@kylinos.cn>
Acked-by: David Hildenbrand (Red Hat) <david@kernel.org>
Reviewed-by: Lance Yang <lance.yang@linux.dev>
---
 include/linux/page-flags.h | 5 +++++
 mm/rmap.c                  | 2 +-
 mm/vmscan.c                | 5 ++---
 3 files changed, 8 insertions(+), 4 deletions(-)

diff --git a/include/linux/page-flags.h b/include/linux/page-flags.h
index f7a0e4af0c73..415e9f2ef616 100644
--- a/include/linux/page-flags.h
+++ b/include/linux/page-flags.h
@@ -724,6 +724,11 @@ static __always_inline bool folio_test_anon(const struct folio *folio)
 	return ((unsigned long)folio->mapping & FOLIO_MAPPING_ANON) != 0;
 }
 
+static __always_inline bool folio_test_lazyfree(const struct folio *folio)
+{
+	return folio_test_anon(folio) && !folio_test_swapbacked(folio);
+}
+
 static __always_inline bool PageAnonNotKsm(const struct page *page)
 {
 	unsigned long flags = (unsigned long)page_folio(page)->mapping;
diff --git a/mm/rmap.c b/mm/rmap.c
index 088723f909e4..6b09be06c707 100644
--- a/mm/rmap.c
+++ b/mm/rmap.c
@@ -2049,7 +2049,7 @@ static bool try_to_unmap_one(struct folio *folio, struct vm_area_struct *vma,
 		}
 
 		if (!pvmw.pte) {
-			if (folio_test_anon(folio) && !folio_test_swapbacked(folio)) {
+			if (folio_test_lazyfree(folio)) {
 				if (unmap_huge_pmd_locked(vma, pvmw.address, pvmw.pmd, folio))
 					goto walk_done;
 				/*
diff --git a/mm/vmscan.c b/mm/vmscan.c
index 8643c0fb9162..1f32c74ec738 100644
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -944,8 +944,7 @@ static void folio_check_dirty_writeback(struct folio *folio,
 	 * They could be mistakenly treated as file lru. So further anon
 	 * test is needed.
 	 */
-	if (!folio_is_file_lru(folio) ||
-	    (folio_test_anon(folio) && !folio_test_swapbacked(folio))) {
+	if (!folio_is_file_lru(folio) || folio_test_lazyfree(folio)) {
 		*dirty = false;
 		*writeback = false;
 		return;
@@ -1489,7 +1488,7 @@ static unsigned int shrink_folio_list(struct list_head *folio_list,
 			}
 		}
 
-		if (folio_test_anon(folio) && !folio_test_swapbacked(folio)) {
+		if (folio_test_lazyfree(folio)) {
 			/* follow __remove_mapping for reference */
 			if (!folio_ref_freeze(folio, 1))
 				goto keep_locked;
-- 
2.51.0

On Fri, Jan 23, 2026 at 4:23 PM Vernon Yang <vernon2gm@gmail.com> wrote:
>
> From: Vernon Yang <yanglincheng@kylinos.cn>
>
> Add folio_test_lazyfree() function to identify lazy-free folios to improve
> code readability.
>
> Signed-off-by: Vernon Yang <yanglincheng@kylinos.cn>
> Acked-by: David Hildenbrand (Red Hat) <david@kernel.org>
> Reviewed-by: Lance Yang <lance.yang@linux.dev>

LGTM,

Reviewed-by: Barry Song <baohua@kernel.org>

On 23/01/26 1:52 pm, Vernon Yang wrote:
> From: Vernon Yang <yanglincheng@kylinos.cn>
>
> Add folio_test_lazyfree() function to identify lazy-free folios to improve
> code readability.
>
> Signed-off-by: Vernon Yang <yanglincheng@kylinos.cn>
> Acked-by: David Hildenbrand (Red Hat) <david@kernel.org>
> Reviewed-by: Lance Yang <lance.yang@linux.dev>

Thanks, this is very useful.

Reviewed-by: Dev Jain <dev.jain@arm.com>

> ---
>  include/linux/page-flags.h | 5 +++++
>  mm/rmap.c                  | 2 +-
>  mm/vmscan.c                | 5 ++---
>  3 files changed, 8 insertions(+), 4 deletions(-)
>
> diff --git a/include/linux/page-flags.h b/include/linux/page-flags.h
> index f7a0e4af0c73..415e9f2ef616 100644
> --- a/include/linux/page-flags.h
> +++ b/include/linux/page-flags.h
> @@ -724,6 +724,11 @@ static __always_inline bool folio_test_anon(const struct folio *folio)
>  	return ((unsigned long)folio->mapping & FOLIO_MAPPING_ANON) != 0;
>  }
>  
> +static __always_inline bool folio_test_lazyfree(const struct folio *folio)
> +{
> +	return folio_test_anon(folio) && !folio_test_swapbacked(folio);
> +}
> +
>  static __always_inline bool PageAnonNotKsm(const struct page *page)
>  {
>  	unsigned long flags = (unsigned long)page_folio(page)->mapping;
> diff --git a/mm/rmap.c b/mm/rmap.c
> index 088723f909e4..6b09be06c707 100644
> --- a/mm/rmap.c
> +++ b/mm/rmap.c
> @@ -2049,7 +2049,7 @@ static bool try_to_unmap_one(struct folio *folio, struct vm_area_struct *vma,
>  		}
>  
>  		if (!pvmw.pte) {
> -			if (folio_test_anon(folio) && !folio_test_swapbacked(folio)) {
> +			if (folio_test_lazyfree(folio)) {
>  				if (unmap_huge_pmd_locked(vma, pvmw.address, pvmw.pmd, folio))
>  					goto walk_done;
>  				/*
> diff --git a/mm/vmscan.c b/mm/vmscan.c
> index 8643c0fb9162..1f32c74ec738 100644
> --- a/mm/vmscan.c
> +++ b/mm/vmscan.c
> @@ -944,8 +944,7 @@ static void folio_check_dirty_writeback(struct folio *folio,
>  	 * They could be mistakenly treated as file lru. So further anon
>  	 * test is needed.
>  	 */
> -	if (!folio_is_file_lru(folio) ||
> -	    (folio_test_anon(folio) && !folio_test_swapbacked(folio))) {
> +	if (!folio_is_file_lru(folio) || folio_test_lazyfree(folio)) {
>  		*dirty = false;
>  		*writeback = false;
>  		return;
> @@ -1489,7 +1488,7 @@ static unsigned int shrink_folio_list(struct list_head *folio_list,
>  			}
>  		}
>  
> -		if (folio_test_anon(folio) && !folio_test_swapbacked(folio)) {
> +		if (folio_test_lazyfree(folio)) {
>  			/* follow __remove_mapping for reference */
>  			if (!folio_ref_freeze(folio, 1))
>  				goto keep_locked;