[PATCH v21 08/19] mm/memcg: add debug checking in lock_page_memcg

From: Alex Shi
Date: Thu Nov 05 2020 - 03:56:45 EST


Add a debug checking in lock_page_memcg, then we could get alarm
if anything wrong here.

Suggested-by: Johannes Weiner <hannes@xxxxxxxxxxx>
Signed-off-by: Alex Shi <alex.shi@xxxxxxxxxxxxxxxxx>
Acked-by: Hugh Dickins <hughd@xxxxxxxxxx>
Acked-by: Johannes Weiner <hannes@xxxxxxxxxxx>
Cc: Johannes Weiner <hannes@xxxxxxxxxxx>
Cc: Michal Hocko <mhocko@xxxxxxxxxx>
Cc: Vladimir Davydov <vdavydov.dev@xxxxxxxxx>
Cc: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Cc: cgroups@xxxxxxxxxxxxxxx
Cc: linux-mm@xxxxxxxxx
Cc: linux-kernel@xxxxxxxxxxxxxxx
---
mm/memcontrol.c | 6 ++++++
1 file changed, 6 insertions(+)

diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index b2aa3b73ab82..157b745031a4 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -2121,6 +2121,12 @@ struct mem_cgroup *lock_page_memcg(struct page *page)
if (unlikely(!memcg))
return NULL;

+#ifdef CONFIG_PROVE_LOCKING
+ local_irq_save(flags);
+ might_lock(&memcg->move_lock);
+ local_irq_restore(flags);
+#endif
+
if (atomic_read(&memcg->moving_account) <= 0)
return memcg;

--
1.8.3.1