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>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 1 insertions, 18 deletions

diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index d5ba631e0ec7..30f938c86453 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -2855,24 +2855,7 @@ __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.