[PATCH] memcg: Fix memcg_kmem_bypass() for remote memcg charging

Zefan Li
2020-05-13T07:28:28Z

While trying to use remote memcg charging in an out-of-tree kernel module
I found it's not working, because the current thread is a workqueue thread.

Signed-off-by: Zefan Li <lizefan-hv44wF8Li93QT0dZR+AlfA@public.gmane.org>
---

No need to queue this for v5.7 as currently no upstream users of this memcg
feature suffer from this bug.

---
mm/memcontrol.c | 2 ++
1 file changed, 2 insertions(+)

diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index a3b97f1..db836fc 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -2802,6 +2802,8 @@ static void memcg_schedule_kmem_cache_create(struct mem_cgroup *memcg,

static inline bool memcg_kmem_bypass(void)
{
+ if (unlikely(current->active_memcg))
+ return false;
if (in_interrupt() || !current->mm || (current->flags & PF_KTHREAD))
return true;
return false;
--
2.7.4