kernfs: account kernfs_node_cache as reclaimable

Similar to commit df206988e03e
("fs: fuse: account fuse_inode slab memory as reclaimable"), these kernfs nodes are currently included in the unreclaimable slab counts - SUnreclaim in /proc/meminfo. And they are reclaimable too and can be freed by kernfs_evict_inode() via /proc/sys/vm/drop_caches easily.

Mark the slab cache reclaimable.

---
 fs/kernfs/mount.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

index 26dd9a50f383..66a699d06c9a 100644
@@ -411,6 +411,6 @@ void __init kernfs_init(void)
 	kernfs_node_cache = kmem_cache_create("kernfs_node_cache",
 					      sizeof(struct kernfs_node),
 					      0,
-					      SLAB_PANIC | SLAB_TYPESAFE_BY_RCU,
+					      SLAB_PANIC | SLAB_TYPESAFE_BY_RCU | SLAB_RECLAIM_ACCOUNT,
 					      NULL);
 }

2.13.0

That evicts the inode, not the kernfs_node. kernfs_node is the backing storage for these filesystems. They aren't reclaimable.

Thanks.

tejun