memcg: avoid unnecessary initialization

* remove over-killing initialization (in fast path)
* makeing the condition for PAGE_CGROUP_FLAG_ACTIVE be more obvious.

Signed-off-by: KAMEAZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Reviewed-by: Li Zefan <lizf@cn.fujitsu.com>
Acked-by: Balbir Singh <balbir@linux.vnet.ibm.com>
Acked-by: Pavel Emelyanov <xemul@openvz.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 8 insertions, 3 deletions

diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index c52c045f515..90ccc132635 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -296,7 +296,7 @@ static void __mem_cgroup_remove_list(struct mem_cgroup_per_zone *mz,
                 MEM_CGROUP_ZSTAT(mz, MEM_CGROUP_ZSTAT_INACTIVE) -= 1;
 
         mem_cgroup_charge_statistics(pc->mem_cgroup, pc->flags, false);
-        list_del_init(&pc->lru);
+        list_del(&pc->lru);
 }
 
 static void __mem_cgroup_add_list(struct mem_cgroup_per_zone *mz,
@@ -559,7 +559,7 @@ retry:
         }
         unlock_page_cgroup(page);
 
-        pc = kmem_cache_zalloc(page_cgroup_cache, gfp_mask);
+        pc = kmem_cache_alloc(page_cgroup_cache, gfp_mask);
         if (pc == NULL)
                 goto err;
 
@@ -606,9 +606,14 @@ retry:
         pc->ref_cnt = 1;
         pc->mem_cgroup = mem;
         pc->page = page;
-        pc->flags = PAGE_CGROUP_FLAG_ACTIVE;
+        /*
+         * If a page is accounted as a page cache, insert to inactive list.
+         * If anon, insert to active list.
+         */
         if (ctype == MEM_CGROUP_CHARGE_TYPE_CACHE)
                 pc->flags = PAGE_CGROUP_FLAG_CACHE;
+        else
+                pc->flags = PAGE_CGROUP_FLAG_ACTIVE;
 
         lock_page_cgroup(page);
         if (page_get_page_cgroup(page)) {