mm: memcg: remove unneeded checks from uncharge_page()

mem_cgroup_uncharge_page() is only called on either freshly allocated
pages without page->mapping or on rmapped PageAnon() pages.  There is no
need to check for a page->mapping that is not an anon_vma.

Signed-off-by: Johannes Weiner <jweiner@redhat.com>
Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Acked-by: Michal Hocko <mhocko@suse.cz>
Cc: Balbir Singh <bsingharora@gmail.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Hugh Dickins <hughd@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index 947be1e2d55f9cebe7990057e149a79c7de118fb..b2ae95160b32521c98cdccf167d8044e7b7c344e 100644 (file)
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -3063,8 +3063,7 @@ void mem_cgroup_uncharge_page(struct page *page)
        /* early check. */
        if (page_mapped(page))
                return;
-       if (page->mapping && !PageAnon(page))
-               return;
+       VM_BUG_ON(page->mapping && !PageAnon(page));
        __mem_cgroup_uncharge_common(page, MEM_CGROUP_CHARGE_TYPE_MAPPED);
 }