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 <[email protected]>
Acked-by: KAMEZAWA Hiroyuki <[email protected]>
Acked-by: Michal Hocko <[email protected]>
Cc: Balbir Singh <[email protected]>
Cc: David Rientjes <[email protected]>
Cc: Hugh Dickins <[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 2450d89486d40e90226cede9dd790fb1e23b389a..71a9774e6ead9af2ac084161dc06edcfd77b2b61 100644 (file)
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -3061,8 +3061,7 @@ 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);
 }