mm: per-node vmstat: show proper vmstats

commit 2ac390370a ("writeback: add
/sys/devices/system/node/<node>/vmstat") added vmstat entry.  But
strangely it only show nr_written and nr_dirtied.

        # cat /sys/devices/system/node/node20/vmstat
        nr_written 0
        nr_dirtied 0

Of course, It's not adequate.  With this patch, the vmstat show all vm
stastics as /proc/vmstat.

        # cat /sys/devices/system/node/node0/vmstat
	nr_free_pages 899224
	nr_inactive_anon 201
	nr_active_anon 17380
	nr_inactive_file 31572
	nr_active_file 28277
	nr_unevictable 0
	nr_mlock 0
	nr_anon_pages 17321
	nr_mapped 8640
	nr_file_pages 60107
	nr_dirty 33
	nr_writeback 0
	nr_slab_reclaimable 6850
	nr_slab_unreclaimable 7604
	nr_page_table_pages 3105
	nr_kernel_stack 175
	nr_unstable 0
	nr_bounce 0
	nr_vmscan_write 0
	nr_writeback_temp 0
	nr_isolated_anon 0
	nr_isolated_file 0
	nr_shmem 260
	nr_dirtied 1050
	nr_written 938
	numa_hit 962872
	numa_miss 0
	numa_foreign 0
	numa_interleave 8617
	numa_local 962872
	numa_other 0
	nr_anon_transparent_hugepages 0

[akpm@linux-foundation.org: no externs in .c files]
Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Michael Rubin <mrubin@google.com>
Cc: Wu Fengguang <fengguang.wu@intel.com>
Acked-by: David Rientjes <rientjes@google.com>
Cc: Randy Dunlap <rdunlap@xenotime.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/drivers/base/node.c b/drivers/base/node.c
index b3b72d6..793f796 100644
--- a/drivers/base/node.c
+++ b/drivers/base/node.c
@@ -7,6 +7,7 @@
 #include <linux/init.h>
 #include <linux/mm.h>
 #include <linux/memory.h>
+#include <linux/vmstat.h>
 #include <linux/node.h>
 #include <linux/hugetlb.h>
 #include <linux/compaction.h>
@@ -179,11 +180,14 @@
 				struct sysdev_attribute *attr, char *buf)
 {
 	int nid = dev->id;
-	return sprintf(buf,
-		"nr_written %lu\n"
-		"nr_dirtied %lu\n",
-		node_page_state(nid, NR_WRITTEN),
-		node_page_state(nid, NR_DIRTIED));
+	int i;
+	int n = 0;
+
+	for (i = 0; i < NR_VM_ZONE_STAT_ITEMS; i++)
+		n += sprintf(buf+n, "%s %lu\n", vmstat_text[i],
+			     node_page_state(nid, i));
+
+	return n;
 }
 static SYSDEV_ATTR(vmstat, S_IRUGO, node_read_vmstat, NULL);