mm/memcg: Add a comment regarding the release `obj'.

Commit Message

Sebastian Andrzej Siewior Feb. 25, 2022, 3:15 p.m. UTC

Please fold into
    mm/memcg: Protect memcg_stock with a local_lock_t

Signed-off-by: Sebastian Andrzej Siewior <[e-mail]>
---
 mm/memcontrol.c | 4 ++++
 1 file changed, 4 insertions(+)

Patch

diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index 7883e2f2af3e8..19d4f9297b0c6 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -3245,6 +3245,10 @@  static struct obj_cgroup *drain_obj_stock(struct memcg_stock_pcp *stock)
 	}
 
 	stock->cached_objcg = NULL;
+	/*
+	 * The `old' objects needs to be released by the caller via
+	 * obj_cgroup_put() outside of memcg_stock_pcp::stock_lock.
+	 */
 	return old;
 }