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Subject[PATCH 3/3] swap: Clear si->swap_map[] in swap_free_cluster()
Date
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.

Signed-off-by: "Huang, Ying" <ying.huang@intel.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Shaohua Li <shli@kernel.org>
Cc: Hugh Dickins <hughd@google.com>
Cc: Minchan Kim <minchan@kernel.org>
---
mm/swapfile.c | 4 +---
1 file changed, 1 insertion(+), 3 deletions(-)

diff --git a/mm/swapfile.c b/mm/swapfile.c
index ef974bbd7715..97a1bd1a7c9a 100644
--- a/mm/swapfile.c
+++ b/mm/swapfile.c
@@ -933,6 +933,7 @@ static void swap_free_cluster(struct swap_info_struct *si, unsigned long idx)
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);
@@ -1309,9 +1310,6 @@ void put_swap_page(struct page *page, swp_entry_t entry)
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);
--
2.16.4
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