memcg swap: use mem_cgroup_uncharge_swap()

That stuff __mem_cgroup_commit_charge_swapin() does with a swap entry, it
has a name and even a declaration: just use mem_cgroup_uncharge_swap().

Signed-off-by: Hugh Dickins <hughd@google.com>
Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index 6995fe0d8b10fa03906b7c40526371f81b41986e..ad40690a95deee9f17dad4b1e00cd231a03741ce 100644 (file)
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -2874,24 +2874,7 @@ __mem_cgroup_commit_charge_swapin(struct page *page, struct mem_cgroup *memcg,
         */
        if (do_swap_account && PageSwapCache(page)) {
                swp_entry_t ent = {.val = page_private(page)};
-               struct mem_cgroup *swap_memcg;
-               unsigned short id;
-
-               id = swap_cgroup_record(ent, 0);
-               rcu_read_lock();
-               swap_memcg = mem_cgroup_lookup(id);
-               if (swap_memcg) {
-                       /*
-                        * This recorded memcg can be obsolete one. So, avoid
-                        * calling css_tryget
-                        */
-                       if (!mem_cgroup_is_root(swap_memcg))
-                               res_counter_uncharge(&swap_memcg->memsw,
-                                                    PAGE_SIZE);
-                       mem_cgroup_swap_statistics(swap_memcg, false);
-                       mem_cgroup_put(swap_memcg);
-               }
-               rcu_read_unlock();
+               mem_cgroup_uncharge_swap(ent);
        }
        /*
         * At swapin, we may charge account against cgroup which has no tasks.