From: Zefan Li <lizefan@xxxxxxxxxx> Subject: memcg: fix memcg_kmem_bypass() for remote memcg charging 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. As we will probably encounter this issue in the future as the users of memalloc_use_memcg() grow, and it's nothing wrong for this usage, it's better we fix it now. Link: http://lkml.kernel.org/r/1d202a12-26fe-0012-ea14-f025ddcd044a@xxxxxxxxxx Signed-off-by: Zefan Li <lizefan@xxxxxxxxxx> Acked-by: Johannes Weiner <hannes@xxxxxxxxxxx> Reviewed-by: Roman Gushchin <guro@xxxxxx> Reviewed-by: Shakeel Butt <shakeelb@xxxxxxxxxx> Acked-by: Michal Hocko <mhocko@xxxxxxxx> Cc: Vladimir Davydov <vdavydov.dev@xxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- mm/memcontrol.c | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-) --- a/mm/memcontrol.c~memcg-fix-memcg_kmem_bypass-for-remote-memcg-charging +++ a/mm/memcontrol.c @@ -2852,7 +2852,12 @@ static void memcg_schedule_kmem_cache_cr static inline bool memcg_kmem_bypass(void) { - if (in_interrupt() || !current->mm || (current->flags & PF_KTHREAD)) + if (in_interrupt()) + return true; + + /* Allow remote memcg charging in kthread contexts. */ + if ((!current->mm || (current->flags & PF_KTHREAD)) && + !current->active_memcg) return true; return false; } _
