From 0435a2fdcb50f8e53a67e98c27708e5d9396b71a Mon Sep 17 00:00:00 2001
From: Johannes Weiner <hannes@cmpxchg.org>
Date: Tue, 31 Jul 2012 16:45:43 -0700
Subject: mm: memcg: split swapin charge function into private and public part

When shmem is charged upon swapin, it does not need to check twice whether
the memory controller is enabled.

Also, shmem pages do not have to be checked for everything that regular
anon pages have to be checked for, so let shmem use the internal version
directly and allow future patches to move around checks that are only
required when swapping in anon pages.

Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Acked-by: Michal Hocko <mhocko@suse.cz>
Cc: David Rientjes <rientjes@google.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Wanpeng Li <liwp.linux@gmail.com>
Cc: Mel Gorman <mel@csn.ul.ie>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
---
 mm/memcontrol.c | 24 +++++++++++++++---------
 1 file changed, 15 insertions(+), 9 deletions(-)

(limited to 'mm')

diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index 10b370345a5b..4cc962d566ce 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -2801,18 +2801,14 @@ int mem_cgroup_newpage_charge(struct page *page,
  * struct page_cgroup is acquired. This refcnt will be consumed by
  * "commit()" or removed by "cancel()"
  */
-int mem_cgroup_try_charge_swapin(struct mm_struct *mm,
-				 struct page *page,
-				 gfp_t mask, struct mem_cgroup **memcgp)
+static int __mem_cgroup_try_charge_swapin(struct mm_struct *mm,
+					  struct page *page,
+					  gfp_t mask,
+					  struct mem_cgroup **memcgp)
 {
 	struct mem_cgroup *memcg;
 	int ret;
 
-	*memcgp = NULL;
-
-	if (mem_cgroup_disabled())
-		return 0;
-
 	if (!do_swap_account)
 		goto charge_cur_mm;
 	/*
@@ -2839,6 +2835,15 @@ charge_cur_mm:
 	return ret;
 }
 
+int mem_cgroup_try_charge_swapin(struct mm_struct *mm, struct page *page,
+				 gfp_t gfp_mask, struct mem_cgroup **memcgp)
+{
+	*memcgp = NULL;
+	if (mem_cgroup_disabled())
+		return 0;
+	return __mem_cgroup_try_charge_swapin(mm, page, gfp_mask, memcgp);
+}
+
 void mem_cgroup_cancel_charge_swapin(struct mem_cgroup *memcg)
 {
 	if (mem_cgroup_disabled())
@@ -2900,7 +2905,8 @@ int mem_cgroup_cache_charge(struct page *page, struct mm_struct *mm,
 	if (!PageSwapCache(page))
 		ret = mem_cgroup_charge_common(page, mm, gfp_mask, type);
 	else { /* page is swapcache/shmem */
-		ret = mem_cgroup_try_charge_swapin(mm, page, gfp_mask, &memcg);
+		ret = __mem_cgroup_try_charge_swapin(mm, page,
+						     gfp_mask, &memcg);
 		if (!ret)
 			__mem_cgroup_commit_charge_swapin(page, memcg, type);
 	}
-- 
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