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. Signed-off-by: Zefan Li <[email protected]> Signed-off-by: Andrew Morton <[email protected]> Reviewed-by: Roman Gushchin <[email protected]> Reviewed-by: Shakeel Butt <[email protected]> Acked-by: Johannes Weiner <[email protected]> Acked-by: Michal Hocko <[email protected]> Cc: Vladimir Davydov <[email protected]> Link: http://lkml.kernel.org/r/[email protected] Signed-off-by: Linus Torvalds <[email protected]>
kawasaki · Jun 2, 2020 · 50d53d7 · 50d53d7
1 parent 4b82ab4
commit 50d53d7
Showing 1 changed file with 6 additions and 1 deletion.
diff --git a/mm/memcontrol.c b/mm/memcontrol.c
@@ -2852,7 +2852,12 @@ static void memcg_schedule_kmem_cache_create(struct mem_cgroup *memcg,
 
 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;
 }