[merged mm-stable] mm-swap-fix-stale-comment-on-swap_info_struct-cluster_info.patch removed from -mm tree

[merged mm-stable] mm-swap-fix-stale-comment-on-swap_info_struct-cluster_info.patch removed from -mm tree

[Andrew Morton]

The quilt patch titled
     Subject: mm/swap: fix stale comment on swap_info_struct::cluster_info
has been removed from the -mm tree.  Its filename was
     mm-swap-fix-stale-comment-on-swap_info_struct-cluster_info.patch

This patch was dropped because it was merged into the mm-stable branch
of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

------------------------------------------------------
From: Youngjun Park <youngjun.park@lge.com>
Subject: mm/swap: fix stale comment on swap_info_struct::cluster_info
Date: Thu, 10 Sep 2026 01:15:51 +0900

Patch series "mm/swap: skip empty clusters in the swapoff scan", v4.

Speed up swapoff and reduce scanning stalls on large, mostly empty swap
devices by skipping empty clusters.  Reduce swapoff time on a 1 TiB device
from 158 ms to 94 ms after filling 128 GiB, and from 392 ms to 73 ms after
filling 512 GiB; expect little benefit when substantial swap data remains.

find_next_to_unuse() walks a swap device one offset at a time.  Slot state
now lives in a per cluster swap table, so patch 2 dismisses an empty
cluster with one counter read instead of SWAPFILE_CLUSTER table reads.

Patch 1 is an unrelated one line comment fix noticed on the way.

A debug test confirmed the skip path runs, and swapoff completed under
load with no DEBUG_VM or lockdep splats.


This patch (of 2):

setup_swap_clusters_info() allocates cluster_info for every swap area, not
only for SSDs.

Link: https://lore.kernel.org/20260909161552.2335971-1-youngjun.park@lge.com
Link: https://lore.kernel.org/20260909161552.2335971-2-youngjun.park@lge.com
Signed-off-by: Youngjun Park <youngjun.park@lge.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Acked-by: Kairui Song <kasong@tencent.com>
Reviewed-by: Barry Song <baohua@kernel.org>
Cc: Baoquan He <baoquan.he@linux.dev>
Cc: Chris Li <chrisl@kernel.org>
Cc: Kemeng Shi <shikemeng@huaweicloud.com>
Cc: Nhat Pham <nphamcs@gmail.com>
---

 include/linux/swap.h |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

--- a/include/linux/swap.h~mm-swap-fix-stale-comment-on-swap_info_struct-cluster_info
+++ a/include/linux/swap.h
@@ -240,7 +240,7 @@ struct swap_info_struct {
 	struct plist_node list;		/* entry in swap_active_head */
 	signed char	type;		/* strange name for an index */
 	unsigned int	max;		/* size of this swap device */
-	struct swap_cluster_info *cluster_info; /* cluster info. Only for SSD */
+	struct swap_cluster_info *cluster_info; /* array, one entry per cluster */
 	struct list_head free_clusters; /* free clusters list */
 	struct list_head full_clusters; /* full clusters list */
 	struct list_head nonfull_clusters[SWAP_NR_ORDERS];
_

Patches currently in -mm which might be from youngjun.park@lge.com are