[PATCH RFC 13/15] mm/huge_memory: mark file folio as accessed more accurately on split

From: Kairui Song <[email protected]>

The behavior of updating the folio's access info isn't consistent for
huge mapping splitting or ordinary unmapping. The page table's young
flag has to be translated into folio's access info.

Right now it only check and set folio's referenced flag, which isn't
enough since folio flags update on access have its rules. Ordinary
unmapping (zapping) calls folio_mark_accessed(), and it also checks
if the VMA has recency to avoid false updates.

So first just use the right helper here to be more consistent.

Signed-off-by: Kairui Song <[email protected]>
---
 mm/huge_memory.c | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/mm/huge_memory.c b/mm/huge_memory.c
index 21c92ee48e46..043c9ac963b4 100644
--- a/mm/huge_memory.c
+++ b/mm/huge_memory.c
@@ -3058,8 +3058,8 @@ static void __split_huge_pud_locked(struct vm_area_struct *vma, pud_t *pud,
 
 	if (!folio_test_dirty(folio) && pud_dirty(old_pud))
 		folio_mark_dirty(folio);
-	if (!folio_test_referenced(folio) && pud_young(old_pud))
-		folio_set_referenced(folio);
+	if (pud_young(old_pud) && vma_has_recency(vma))
+		folio_mark_accessed(folio);
 	folio_remove_rmap_pud(folio, page, vma);
 	add_mm_counter(vma->vm_mm, mm_counter_file(folio),
 		-HPAGE_PUD_NR);
@@ -3181,8 +3181,8 @@ static void __split_huge_pmd_locked(struct vm_area_struct *vma, pmd_t *pmd,
 			folio = page_folio(page);
 			if (!folio_test_dirty(folio) && pmd_dirty(old_pmd))
 				folio_mark_dirty(folio);
-			if (!folio_test_referenced(folio) && pmd_young(old_pmd))
-				folio_set_referenced(folio);
+			if (pmd_young(old_pmd) && vma_has_recency(vma))
+				folio_mark_accessed(folio);
 			folio_remove_rmap_pmd(folio, page, vma);
 			add_mm_counter(mm, mm_counter_file(folio), -HPAGE_PMD_NR);
 			folio_put(folio);

-- 
2.55.0