mm, vmstat: print node-based stats in zoneinfo file

There are a number of stats that were previously accessible via zoneinfo
that are now invisible.  While it is possible to create a new file for
the node stats, this may be missed by users.  Instead this patch prints
the stats under the first populated zone in /proc/zoneinfo.

Link: http://lkml.kernel.org/r/1467970510-21195-34-git-send-email-mgorman@techsingularity.net
Signed-off-by: Mel Gorman <mgorman@techsingularity.net>
Acked-by: Hillf Danton <hillf.zj@alibaba-inc.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Rik van Riel <riel@surriel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 24 insertions, 0 deletions

diff --git a/mm/vmstat.c b/mm/vmstat.c
index 5caaf3f7b8ab..ac509572a50b 100644
--- a/mm/vmstat.c
+++ b/mm/vmstat.c
@@ -1415,11 +1415,35 @@ static const struct file_operations pagetypeinfo_file_ops = {
         .release        = seq_release,
 };
 
+static bool is_zone_first_populated(pg_data_t *pgdat, struct zone *zone)
+{
+        int zid;
+
+        for (zid = 0; zid < MAX_NR_ZONES; zid++) {
+                struct zone *compare = &pgdat->node_zones[zid];
+
+                if (populated_zone(compare))
+                        return zone == compare;
+        }
+
+        /* The zone must be somewhere! */
+        WARN_ON_ONCE(1);
+        return false;
+}
+
 static void zoneinfo_show_print(struct seq_file *m, pg_data_t *pgdat,
                                                         struct zone *zone)
 {
         int i;
         seq_printf(m, "Node %d, zone %8s", pgdat->node_id, zone->name);
+        if (is_zone_first_populated(pgdat, zone)) {
+                seq_printf(m, "\n  per-node stats");
+                for (i = 0; i < NR_VM_NODE_STAT_ITEMS; i++) {
+                        seq_printf(m, "\n      %-12s %lu",
+                                vmstat_text[i + NR_VM_ZONE_STAT_ITEMS],
+                                node_page_state(pgdat, i));
+                }
+        }
         seq_printf(m,
                    "\n  pages free     %lu"
                    "\n        min      %lu"