LRU_SKIP can only be returned if we don't ever dropped lru lock, or
we need to return LRU_RETRY to restart from the head of lru list.
Otherwise, the iteration might continue from a cursor position that
was freed while the locks were dropped.
Actually we may need to introduce another LRU_STOP to really terminate
the ongoing shrinking scan process, when we encounter a warm page
already in the swap cache. The current list_lru implementation
doesn't have this function to early break from __list_lru_walk_one.
Fixes: b5ba474f3f51 ("zswap: shrink zswap pool based on memory pressure")
Acked-by: Johannes Weiner <hannes@xxxxxxxxxxx>
Reviewed-by: Nhat Pham <nphamcs@xxxxxxxxx>
Signed-off-by: Chengming Zhou <zhouchengming@xxxxxxxxxxxxx>
---
mm/zswap.c | 4 +---
1 file changed, 1 insertion(+), 3 deletions(-)
diff --git a/mm/zswap.c b/mm/zswap.c
index 00e90b9b5417..81cb3790e0dd 100644
--- a/mm/zswap.c
+++ b/mm/zswap.c
@@ -901,10 +901,8 @@ static enum lru_status shrink_memcg_cb(struct list_head *item, struct list_lru_o
* into the warmer region. We should terminate shrinking (if we're in the dynamic
* shrinker context).
*/
- if (writeback_result == -EEXIST && encountered_page_in_swapcache) {
- ret = LRU_SKIP;
+ if (writeback_result == -EEXIST && encountered_page_in_swapcache)
*encountered_page_in_swapcache = true;
- }
goto put_unlock;
}
--
b4 0.10.1
