From: Kemeng Shi Date: Tue, 25 Mar 2025 16:25:25 +0000 (+0800) Subject: mm: swap: drop last SWAP_MAP_SHMEM flag in batch in swap_entries_put_nr() X-Git-Tag: v6.16-rc1~92^2~236 X-Git-Url: https://git.kernel.dk/?a=commitdiff_plain;h=f2252acf444764e7de7380201c518ee5ab6fd9da;p=linux-block.git mm: swap: drop last SWAP_MAP_SHMEM flag in batch in swap_entries_put_nr() The SWAP_MAP_SHMEM indicates last map from shmem. Therefore we can drop SWAP_MAP_SHMEM in batch in similar way to drop last ref count in batch. Link: https://lkml.kernel.org/r/20250325162528.68385-6-shikemeng@huaweicloud.com Signed-off-by: Kemeng Shi Reviewed-by: Tim Chen Reviewed-by: Baoquan He Cc: Kairui Song Signed-off-by: Andrew Morton --- diff --git a/mm/swapfile.c b/mm/swapfile.c index f8fe507be4f3..668684dc9efa 100644 --- a/mm/swapfile.c +++ b/mm/swapfile.c @@ -192,7 +192,7 @@ static bool swap_is_last_map(struct swap_info_struct *si, unsigned char *map_end = map + nr_pages; unsigned char count = *map; - if (swap_count(count) != 1) + if (swap_count(count) != 1 && swap_count(count) != SWAP_MAP_SHMEM) return false; while (++map < map_end) { @@ -1487,7 +1487,10 @@ static bool swap_entries_put_nr(struct swap_info_struct *si, unsigned char count; int i; - if (nr <= 1 || swap_count(data_race(si->swap_map[offset])) != 1) + if (nr <= 1) + goto fallback; + count = swap_count(data_race(si->swap_map[offset])); + if (count != 1 && count != SWAP_MAP_SHMEM) goto fallback; /* cross into another cluster */ if (nr > SWAPFILE_CLUSTER - offset % SWAPFILE_CLUSTER)