memcg: show swap usage in stat file

We now count MEM_CGROUP_STAT_SWAPOUT, so we can show swap usage.  It would
be useful for users to show swap usage in memory.stat file, because they
don't need calculate memsw.usage - res.usage to know swap usage.

Signed-off-by: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Reviewed-by: Balbir Singh <balbir@linux.vnet.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 14 insertions, 3 deletions

diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index 2011f15278fd..e2b98a6875c0 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -2676,6 +2676,7 @@ enum {
         MCS_MAPPED_FILE,
         MCS_PGPGIN,
         MCS_PGPGOUT,
+        MCS_SWAP,
         MCS_INACTIVE_ANON,
         MCS_ACTIVE_ANON,
         MCS_INACTIVE_FILE,
@@ -2697,6 +2698,7 @@ struct {
         {"mapped_file", "total_mapped_file"},
         {"pgpgin", "total_pgpgin"},
         {"pgpgout", "total_pgpgout"},
+        {"swap", "total_swap"},
         {"inactive_anon", "total_inactive_anon"},
         {"active_anon", "total_active_anon"},
         {"inactive_file", "total_inactive_file"},
@@ -2721,6 +2723,10 @@ static int mem_cgroup_get_local_stat(struct mem_cgroup *mem, void *data)
         s->stat[MCS_PGPGIN] += val;
         val = mem_cgroup_read_stat(&mem->stat, MEM_CGROUP_STAT_PGPGOUT_COUNT);
         s->stat[MCS_PGPGOUT] += val;
+        if (do_swap_account) {
+                val = mem_cgroup_read_stat(&mem->stat, MEM_CGROUP_STAT_SWAPOUT);
+                s->stat[MCS_SWAP] += val * PAGE_SIZE;
+        }
 
         /* per zone stat */
         val = mem_cgroup_get_local_zonestat(mem, LRU_INACTIVE_ANON);
@@ -2752,8 +2758,11 @@ static int mem_control_stat_show(struct cgroup *cont, struct cftype *cft,
         memset(&mystat, 0, sizeof(mystat));
         mem_cgroup_get_local_stat(mem_cont, &mystat);
 
-        for (i = 0; i < NR_MCS_STAT; i++)
+        for (i = 0; i < NR_MCS_STAT; i++) {
+                if (i == MCS_SWAP && !do_swap_account)
+                        continue;
                 cb->fill(cb, memcg_stat_strings[i].local_name, mystat.stat[i]);
+        }
 
         /* Hierarchical information */
         {
@@ -2766,9 +2775,11 @@ static int mem_control_stat_show(struct cgroup *cont, struct cftype *cft,
 
         memset(&mystat, 0, sizeof(mystat));
         mem_cgroup_get_total_stat(mem_cont, &mystat);
-        for (i = 0; i < NR_MCS_STAT; i++)
+        for (i = 0; i < NR_MCS_STAT; i++) {
+                if (i == MCS_SWAP && !do_swap_account)
+                        continue;
                 cb->fill(cb, memcg_stat_strings[i].total_name, mystat.stat[i]);
-
+        }
 
 #ifdef CONFIG_DEBUG_VM
         cb->fill(cb, "inactive_ratio", calc_inactive_ratio(mem_cont, NULL));