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| author | Youngjun Park <youngjun.park@lge.com> | 2026-09-10 01:15:51 +0900 |
|---|---|---|
| committer | Andrew Morton <akpm@linux-foundation.org> | 2026-09-29 23:12:39 -0700 |
| commit | a50e56f91d34675b73ca65deebdfa8ed60cbfb83 (patch) | |
| tree | 287125900a95a01eb93ff5963876ea39d1ea98d9 /include | |
| parent | a82d3d85c508838c7f0d731aa1d08c28a93f09e5 (diff) | |
| download | linux-next-a50e56f91d34675b73ca65deebdfa8ed60cbfb83.tar.gz linux-next-a50e56f91d34675b73ca65deebdfa8ed60cbfb83.zip | |
mm/swap: fix stale comment on swap_info_struct::cluster_info
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>
Diffstat (limited to 'include')
| -rw-r--r-- | include/linux/swap.h | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/include/linux/swap.h b/include/linux/swap.h index a37ad8375e01..61005501888c 100644 --- a/include/linux/swap.h +++ b/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]; |