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.
Signed-off-by: Kemeng Shi <shikemeng@xxxxxxxxxxxxxxx>
Reviewed-by: Tim Chen <tim.c.chen@xxxxxxxxxxxxxxx>
---
mm/swapfile.c | 7 +++++--
1 file changed, 5 insertions(+), 2 deletions(-)
diff --git a/mm/swapfile.c b/mm/swapfile.c
index e83519fbd40e..6f11619665e8 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) {
@@ -1479,7 +1479,10 @@ 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)
--
2.30.0
