[PATCH v2 1/5] mm: khugepaged: expand the is_refcount_suitable() to support file folios
From: Baolin Wang
Date: Tue Aug 20 2024 - 05:49:56 EST
Expand the is_refcount_suitable() to support reference checks for file folios,
as preparation for supporting shmem mTHP collapse.
Signed-off-by: Baolin Wang <baolin.wang@xxxxxxxxxxxxxxxxx>
---
mm/khugepaged.c | 11 ++++++-----
1 file changed, 6 insertions(+), 5 deletions(-)
diff --git a/mm/khugepaged.c b/mm/khugepaged.c
index cdd1d8655a76..76f05215ee87 100644
--- a/mm/khugepaged.c
+++ b/mm/khugepaged.c
@@ -546,12 +546,14 @@ static void release_pte_pages(pte_t *pte, pte_t *_pte,
static bool is_refcount_suitable(struct folio *folio)
{
- int expected_refcount;
+ int expected_refcount = folio_mapcount(folio);
- expected_refcount = folio_mapcount(folio);
- if (folio_test_swapcache(folio))
+ if (!folio_test_anon(folio) || folio_test_swapcache(folio))
expected_refcount += folio_nr_pages(folio);
+ if (folio_test_private(folio))
+ expected_refcount++;
+
return folio_ref_count(folio) == expected_refcount;
}
@@ -2285,8 +2287,7 @@ static int hpage_collapse_scan_file(struct mm_struct *mm, unsigned long addr,
break;
}
- if (folio_ref_count(folio) !=
- 1 + folio_mapcount(folio) + folio_test_private(folio)) {
+ if (!is_refcount_suitable(folio)) {
result = SCAN_PAGE_COUNT;
break;
}
--
2.39.3