memcg: charged pages always have valid per-memcg zone info

page_cgroup_zoneinfo() will never return NULL for a charged page, remove
the check for it in mem_cgroup_get_reclaim_stat_from_page().

Signed-off-by: Johannes Weiner <[email protected]>
Acked-by: KAMEZAWA Hiroyuki <[email protected]>
Cc: Daisuke Nishimura <[email protected]>
Cc: Balbir Singh <[email protected]>
Reviewed-by: Minchan Kim <[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 660dfc27d971e83a910e6742eff48576afc048d7..b35a28d80ab59eb8919e5ae85cc624a7a80455e0 100644 (file)
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -1043,9 +1043,6 @@ mem_cgroup_get_reclaim_stat_from_page(struct page *page)
        /* Ensure pc->mem_cgroup is visible after reading PCG_USED. */
        smp_rmb();
        mz = page_cgroup_zoneinfo(pc->mem_cgroup, page);
-       if (!mz)
-               return NULL;
-
        return &mz->reclaim_stat;
 }