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>

diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index 2011f15278fd6eba5c9c462119bc25b6b348fadc..e2b98a6875c079b36f103b724130462591094735 100644 (file)
--- 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));