Comments in file include/linux/shrinker.h says that
`count_objects` of `struct shrinker` should return SHRINK_EMPTY
when there are no objects to free.

> If there are no objects to free, it should return SHRINK_EMPTY,
> while 0 is returned in cases of the number of freeable items cannot
> be determined or shrinker should skip this cache for this time
> (e.g., their number is below shrinkable limit).

Signed-off-by: Chen Linxuan <chenlinxuan@uniontech.com>
---
 fs/erofs/zutil.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/fs/erofs/zutil.c b/fs/erofs/zutil.c
index 0dd65cefce33..83fbcab70a92 100644
--- a/fs/erofs/zutil.c
+++ b/fs/erofs/zutil.c
@@ -243,7 +243,7 @@ void erofs_shrinker_unregister(struct super_block *sb)
 static unsigned long erofs_shrink_count(struct shrinker *shrink,
 					struct shrink_control *sc)
 {
-	return atomic_long_read(&erofs_global_shrink_cnt);
+	return atomic_long_read(&erofs_global_shrink_cnt) ?: SHRINK_EMPTY;
 }
 
 static unsigned long erofs_shrink_scan(struct shrinker *shrink,
-- 
2.43.0

On 2025/1/16 16:33, Chen Linxuan wrote:
> Comments in file include/linux/shrinker.h says that
> `count_objects` of `struct shrinker` should return SHRINK_EMPTY
> when there are no objects to free.
> 
>> If there are no objects to free, it should return SHRINK_EMPTY,
>> while 0 is returned in cases of the number of freeable items cannot
>> be determined or shrinker should skip this cache for this time
>> (e.g., their number is below shrinkable limit).
> 
> Signed-off-by: Chen Linxuan <chenlinxuan@uniontech.com>

Reviewed-by: Gao Xiang <hsiangkao@linux.alibaba.com>

Thanks,
Gao Xiang