[PATCH mm-new v8 3/4] mm: add folio_test_lazyfree helper

Vernon Yang
2026-02-21T09:40:03Z

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>
Reviewed-by: Dev Jain <dev.jain@arm.com>
Reviewed-by: Barry Song <baohua@kernel.org>
---
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 fb6a83fe88b0..0426cac91c0b 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 0f00570d1b9e..bff8f222004e 100644
--- a/mm/rmap.c
+++ b/mm/rmap.c
@@ -2046,7 +2046,7 @@ 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 6a87ac7be43c..9ce3f54f43b8 100644
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -963,8 +963,7 @@ 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;
@@ -1508,7 +1507,7 @@ 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