2 files changed, 27 insertions, 1 deletions

diff --git a/include/linux/memcontrol.h b/include/linux/memcontrol.h
index 4ec712967f7c..085cdcd817b0 100644
--- a/include/linux/memcontrol.h
+++ b/include/linux/memcontrol.h
@@ -64,6 +64,12 @@ extern int mem_cgroup_prepare_migration(struct page *page);
 extern void mem_cgroup_end_migration(struct page *page);
 extern void mem_cgroup_page_migration(struct page *page, struct page *newpage);
 
+/*
+ * For memory reclaim.
+ */
+extern int mem_cgroup_calc_mapped_ratio(struct mem_cgroup *mem);
+
+
 #else /* CONFIG_CGROUP_MEM_CONT */
 static inline void mm_init_cgroup(struct mm_struct *mm,
                                         struct task_struct *p)
@@ -135,7 +141,10 @@ mem_cgroup_page_migration(struct page *page, struct page *newpage)
 {
 }
 
-
+static inline int mem_cgroup_calc_mapped_ratio(struct mem_cgroup *mem)
+{
+        return 0;
+}
 #endif /* CONFIG_CGROUP_MEM_CONT */
 
 #endif /* _LINUX_MEMCONTROL_H */
diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index 1637575d3339..2ef214ed5cf8 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -420,6 +420,23 @@ void mem_cgroup_move_lists(struct page_cgroup *pc, bool active)
         spin_unlock(&mem->lru_lock);
 }
 
+/*
+ * Calculate mapped_ratio under memory controller. This will be used in
+ * vmscan.c for deteremining we have to reclaim mapped pages.
+ */
+int mem_cgroup_calc_mapped_ratio(struct mem_cgroup *mem)
+{
+        long total, rss;
+
+        /*
+         * usage is recorded in bytes. But, here, we assume the number of
+         * physical pages can be represented by "long" on any arch.
+         */
+        total = (long) (mem->res.usage >> PAGE_SHIFT) + 1L;
+        rss = (long)mem_cgroup_read_stat(&mem->stat, MEM_CGROUP_STAT_RSS);
+        return (int)((rss * 100L) / total);
+}
+
 unsigned long mem_cgroup_isolate_pages(unsigned long nr_to_scan,
                                         struct list_head *dst,
                                         unsigned long *scanned, int order,