[RFC PATCH v1 3/4] mm: Fix demotion-only scanning anon pages

Mina Almasry
2022-11-22T20:38:47Z

This is likely a missed change from commit a2a36488a61c ("mm/vmscan: Consider
anonymous pages without swap"). Current logic is if !may_swap _or_
!can_reclaim_anon_pages() then we don't scan anon memory.

This should be an 'and'. We would like to scan anon memory if we may swap
or if we can_reclaim_anon_pages().

Fixes: commit a2a36488a61c ("mm/vmscan: Consider anonymous pages without swap")

Signed-off-by: Mina Almasry <almasrymina-hpIqsD4AKlfQT0dZR+AlfA@public.gmane.org>
---
mm/vmscan.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/mm/vmscan.c b/mm/vmscan.c
index 8c1f5416d789..d7e509b3f07f 100644
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -2931,7 +2931,7 @@ static void get_scan_count(struct lruvec *lruvec, struct scan_control *sc,
enum lru_list lru;

/* If we have no swap space, do not bother scanning anon folios. */
- if (!sc->may_swap || !can_reclaim_anon_pages(memcg, pgdat->node_id, sc)) {
+ if (!sc->may_swap && !can_reclaim_anon_pages(memcg, pgdat->node_id, sc)) {
scan_balance = SCAN_FILE;
goto out;
}