[PATCH 1/6] mm: swap: avoid losting cluster in swap_reclaim_full_clusters()

From: Kemeng Shi
Date: Sat Feb 22 2025 - 02:12:49 EST


If no swap cache is reclaimed, cluster taken off from full_clusters list
will not be put in any list and may not be reused. Do relocate_cluster
for such cluster to fix the issue.

Fixes: 3b644773eefda ("mm, swap: reduce contention on device lock")
Signed-off-by: Kemeng Shi <shikemeng@xxxxxxxxxxxxxxx>
---
mm/swapfile.c | 4 ++++
1 file changed, 4 insertions(+)

diff --git a/mm/swapfile.c b/mm/swapfile.c
index 34baefb000b5..e5f58ab86329 100644
--- a/mm/swapfile.c
+++ b/mm/swapfile.c
@@ -861,6 +861,10 @@ static void swap_reclaim_full_clusters(struct swap_info_struct *si, bool force)
offset++;
}

+ /* in case no swap cache is reclaimed */
+ if (ci->flags == CLUSTER_FLAG_NONE)
+ relocate_cluster(si, ci);
+
unlock_cluster(ci);
if (to_scan <= 0)
break;
--
2.30.0