[PATCH 1/2] mm/zsmalloc: fix class per-fullness zspage counts

[Chengming Zhou <chengming.zhou@linux.dev>]

We always use insert_zspage() and remove_zspage() to update zspage's
fullness location, which will account correctly.

But this special async free path use "splice" instead of remove_zspage(),
so the per-fullness zspage count for ZS_INUSE_RATIO_0 won't decrease.

Fix it by decreasing when iterate over the zspage free list.

Signed-off-by: Chengming Zhou <chengming.zhou@linux.dev>
---
 mm/zsmalloc.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/mm/zsmalloc.c b/mm/zsmalloc.c
index fec1a39e5bbe..7fc25fa4e6b3 100644
--- a/mm/zsmalloc.c
+++ b/mm/zsmalloc.c
@@ -1883,6 +1883,7 @@ static void async_free_zspage(struct work_struct *work)
 
 		class = zspage_class(pool, zspage);
 		spin_lock(&class->lock);
+		class_stat_dec(class, ZS_INUSE_RATIO_0, 1);
 		__free_zspage(pool, class, zspage);
 		spin_unlock(&class->lock);
 	}
-- 
2.20.1