[PATCH v7 10/10] mm/memcg: add debug checking in lock_page_memcg

Alex Shi
2019-12-25T09:05:13Z

This extra irq disable/enable and BUG_ON checking costs 5% readtwice
performance on a 2 socket * 26 cores * HT box. So it's a temporary
debugging and need to be remove finially.

Signed-off-by: Alex Shi <alex.shi@linux.alibaba.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Vladimir Davydov <vdavydov.dev@gmail.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: cgroups@vger.kernel.org
Cc: linux-mm@kvack.org
Cc: linux-kernel@vger.kernel.org
---
mm/memcontrol.c | 5 +++++
1 file changed, 5 insertions(+)

diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index 33bf086faed0..1512be4d8bde 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -2022,6 +2022,11 @@ struct mem_cgroup *lock_page_memcg(struct page *page)
if (unlikely(!memcg))
return NULL;

+ /* temporary lockdep checking, need remove */
+ local_irq_save(flags);
+ might_lock(&memcg->move_lock);
+ local_irq_restore(flags);
+
if (atomic_read(&memcg->moving_account) <= 0)
return memcg;

--
1.8.3.1