On 4/3/20 4:29 AM, Kirill A. Shutemov wrote:
Having a page in LRU add cache offsets page refcount and gives
false-negative on PageLRU(). It reduces collapse success rate.
Drain all LRU add caches before scanning. It happens relatively
rare and should not disturb the system too much.
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@xxxxxxxxxxxxxxx>
Acked-by: Yang Shi <yang.shi@xxxxxxxxxxxxxxxxx>
---
mm/khugepaged.c | 2 ++
1 file changed, 2 insertions(+)
diff --git a/mm/khugepaged.c b/mm/khugepaged.c
index 14d7afc90786..fdc10ffde1ca 100644
--- a/mm/khugepaged.c
+++ b/mm/khugepaged.c
@@ -2065,6 +2065,8 @@ static void khugepaged_do_scan(void)
barrier(); /* write khugepaged_pages_to_scan to local stack */
+ lru_add_drain_all();
+
while (progress < pages) {
if (!khugepaged_prealloc_page(&hpage, &wait))
break;
