[PATCH] mm/memcg: update page struct member in comments

[Alex Shi <alex.shi@linux.alibaba.com>]

The page->mem_cgroup member is replaced by memcg_data, and add a helper
page_memcg() for it. Need to update comments to avoid confusing.

Signed-off-by: Alex Shi <alex.shi@linux.alibaba.com>
Cc: Johannes Weiner <hannes@cmpxchg.org> 
Cc: Michal Hocko <mhocko@kernel.org> 
Cc: Vladimir Davydov <vdavydov.dev@gmail.com> 
Cc: Andrew Morton <akpm@linux-foundation.org> 
Cc: cgroups@vger.kernel.org 
Cc: linux-mm@kvack.org 
Cc: linux-kernel@vger.kernel.org 
---
 mm/memcontrol.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index b2aa3b73ab82..8a8debea34fc 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -1310,7 +1310,7 @@ int mem_cgroup_scan_tasks(struct mem_cgroup *memcg,
  * @page: the page
  * @pgdat: pgdat of the page
  *
- * This function relies on page->mem_cgroup being stable - see the
+ * This function relies on page_memcg(page) being stable - see the
  * access rules in commit_charge().
  */
 struct lruvec *mem_cgroup_page_lruvec(struct page *page, struct pglist_data *pgdat)
@@ -2862,7 +2862,7 @@ static void commit_charge(struct page *page, struct mem_cgroup *memcg)
 {
 	VM_BUG_ON_PAGE(page_memcg(page), page);
 	/*
-	 * Any of the following ensures page->mem_cgroup stability:
+	 * Any of the following ensures page_memcg(page) stability:
 	 *
 	 * - the page lock
 	 * - LRU isolation
-- 
1.8.3.1