The MADV_FREE pages check in folio_check_dirty_writeback is a bit hard to
follow. Add a comment to make the code clear.
Suggested-by: Huang, Ying <ying.huang@xxxxxxxxx>
Signed-off-by: Miaohe Lin <linmiaohe@xxxxxxxxxx>
Reviewed-by: Christoph Hellwig <hch@xxxxxx>
Reviewed-by: Oscar Salvador <osalvador@xxxxxxx>
---
mm/vmscan.c | 5 ++++-
1 file changed, 4 insertions(+), 1 deletion(-)
diff --git a/mm/vmscan.c b/mm/vmscan.c
index 99a572f01cb4..913eb565140c 100644
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -1438,7 +1438,10 @@ static void folio_check_dirty_writeback(struct folio *folio,
/*
* Anonymous pages are not handled by flushers and must be written
- * from reclaim context. Do not stall reclaim based on them
+ * from reclaim context. Do not stall reclaim based on them.
+ * MADV_FREE anonymous pages are put into inactive file list too.
+ * 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))) {
--
2.23.0
