[patch 050/101] mm, vmstat: print node-based stats in zoneinfo file

[patch 050/101] mm, vmstat: print node-based stats in zoneinfo file

[akpm]

From: Mel Gorman <mgorman@techsingularity.net>
Subject: 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>
---

 mm/vmstat.c |   24 ++++++++++++++++++++++++
 1 file changed, 24 insertions(+)

diff -puN mm/vmstat.c~mm-vmstat-print-node-based-stats-in-zoneinfo-file mm/vmstat.c
--- a/mm/vmstat.c~mm-vmstat-print-node-based-stats-in-zoneinfo-file
+++ a/mm/vmstat.c
@@ -1415,11 +1415,35 @@ static const struct file_operations page
 	.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"
_