[RFC][-mm] [2/2] Simple stats for memory resource controller

[Balaji Rao]

This patch implements trivial statistics for the memory resource controller.

Signed-off-by: Balaji Rao <balajirrao at gmail.com>
CC: Balbir Singh <balbir at linux.vnet.ibm.com>
CC: Dhaval Giani <dhaval at linux.vnet.ibm.com>


diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index eb681a6..84f3fe5 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -45,6 +45,8 @@ enum mem_cgroup_stat_index {
 	 */
 	MEM_CGROUP_STAT_CACHE, 	   /* # of pages charged as cache */
 	MEM_CGROUP_STAT_RSS,	   /* # of pages charged as rss */
+	MEM_CGROUP_STAT_PGIN_COUNT,	/* # of pages paged in */
+	MEM_CGROUP_STAT_PGOUT_COUNT,	/* # of pages paged out */
 
 	MEM_CGROUP_STAT_NSTATS,
 };
@@ -196,6 +198,13 @@ static void mem_cgroup_charge_statistics(struct mem_cgroup *mem, int flags,
 		__mem_cgroup_stat_add_safe(stat, MEM_CGROUP_STAT_CACHE, val);
 	else
 		__mem_cgroup_stat_add_safe(stat, MEM_CGROUP_STAT_RSS, val);
+
+	if (charge)
+		__mem_cgroup_stat_add_safe(stat,
+				MEM_CGROUP_STAT_PGIN_COUNT, 1);
+	else
+		__mem_cgroup_stat_add_safe(stat,
+				MEM_CGROUP_STAT_PGOUT_COUNT, 1);
 }
 
 static struct mem_cgroup_per_zone *
@@ -886,6 +895,8 @@ static const struct mem_cgroup_stat_desc {
 } mem_cgroup_stat_desc[] = {
 	[MEM_CGROUP_STAT_CACHE] = { "cache", PAGE_SIZE, },
 	[MEM_CGROUP_STAT_RSS] = { "rss", PAGE_SIZE, },
+	[MEM_CGROUP_STAT_PGIN_COUNT] = {"page_in_count", 1, },
+	[MEM_CGROUP_STAT_PGOUT_COUNT] = {"page_out_count", 1, },
 };
 
 static int mem_control_stat_show(struct cgroup *cont, struct cftype *cft,