The patch titled
Subject: mm/swapfile.c: clear si->swap_map[] in swap_free_cluster()
has been added to the -mm tree. Its filename is
swap-clear-si-swap_map-in-swap_free_cluster.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/swap-clear-si-swap_map-in-swap_free_cluster.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/swap-clear-si-swap_map-in-swap_free_cluster.patch
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------------------------------------------------------
From: Huang Ying <ying.huang@xxxxxxxxx>
Subject: mm/swapfile.c: clear si->swap_map[] in swap_free_cluster()
si->swap_map[] of the swap entries in cluster needs to be cleared during
freeing. Previously, this is done in the caller of swap_free_cluster().
This may cause code duplication (one user now, will add more users later)
and lock/unlock cluster unnecessarily. In this patch, the clearing code
is moved to swap_free_cluster() to avoid the downside.
Link: http://lkml.kernel.org/r/20180827075535.17406-4-ying.huang@xxxxxxxxx
Signed-off-by: "Huang, Ying" <ying.huang@xxxxxxxxx>
Reviewed-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Cc: Dave Hansen <dave.hansen@xxxxxxxxxxxxxxx>
Cc: Michal Hocko <mhocko@xxxxxxxx>
Cc: Johannes Weiner <hannes@xxxxxxxxxxx>
Cc: Shaohua Li <shli@xxxxxxxxxx>
Cc: Hugh Dickins <hughd@xxxxxxxxxx>
Cc: Minchan Kim <minchan@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/swapfile.c | 4 +---
1 file changed, 1 insertion(+), 3 deletions(-)
--- a/mm/swapfile.c~swap-clear-si-swap_map-in-swap_free_cluster
+++ a/mm/swapfile.c
@@ -932,6 +932,7 @@ static void swap_free_cluster(struct swa
struct swap_cluster_info *ci;
ci = lock_cluster(si, offset);
+ memset(si->swap_map + offset, 0, SWAPFILE_CLUSTER);
cluster_set_count_flag(ci, 0, 0);
free_cluster(si, idx);
unlock_cluster(ci);
@@ -1250,9 +1251,6 @@ void put_swap_page(struct page *page, sw
if (free_entries == SWAPFILE_CLUSTER) {
unlock_cluster_or_swap_info(si, ci);
spin_lock(&si->lock);
- ci = lock_cluster(si, offset);
- memset(map, 0, SWAPFILE_CLUSTER);
- unlock_cluster(ci);
mem_cgroup_uncharge_swap(entry, SWAPFILE_CLUSTER);
swap_free_cluster(si, idx);
spin_unlock(&si->lock);
_
Patches currently in -mm which might be from ying.huang@xxxxxxxxx are
swap-use-__try_to_reclaim_swap-in-free_swap_and_cache.patch
swap-call-free_swap_slot-in-__swap_entry_free.patch
swap-clear-si-swap_map-in-swap_free_cluster.patch
mm-swap-fix-race-between-swapoff-and-some-swap-operations.patch
mm-swap-fix-race-between-swapoff-and-some-swap-operations-v6.patch
mm-fix-race-between-swapoff-and-mincore.patch
