memcg: fix build warning and avoid checking for mem != null again and again

Fix build warning, "mem_cgroup_is_obsolete defined but not used" when
CONFIG_DEBUG_VM is not set.  Also avoid checking for !mem again and again.

Signed-off-by: Nikanth Karthikesan <[email protected]>
Acked-by: Pekka Enberg <[email protected]>
Acked-by: KAMEZAWA Hiroyuki <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>

diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index 4a747a27a22f34c1e50fef0744e8dbcb57f880c6..78eb8552818b6b94d4add7ec06ecdc881add1f67 100644 (file)
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -314,14 +314,6 @@ static struct mem_cgroup *try_get_mem_cgroup_from_mm(struct mm_struct *mm)
        return mem;
 }
 
-static bool mem_cgroup_is_obsolete(struct mem_cgroup *mem)
-{
-       if (!mem)
-               return true;
-       return css_is_removed(&mem->css);
-}
-
-
 /*
  * Call callback function against all cgroup under hierarchy tree.
  */
@@ -932,7 +924,7 @@ static int __mem_cgroup_try_charge(struct mm_struct *mm,
        if (unlikely(!mem))
                return 0;
 
-       VM_BUG_ON(!mem || mem_cgroup_is_obsolete(mem));
+       VM_BUG_ON(css_is_removed(&mem->css));
 
        while (1) {
                int ret;