[PATCH] show Active/Inactive on per-node meminfo

  The patch below enable to display the size of Active/Inactive pages on
  per-node meminfo (/sys/devices/system/node/node%d/meminfo) like
  /proc/meminfo.

  By a little change to procps, "vmstat -a" can show these statistics about
  particular node.

From: mita akinobu <amgta@yacht.ocn.ne.jp>

  get_zone_counts() is used by max_sane_readahead(), and
  max_sane_readahead() is often called in filemap_nopage().
Signed-off-by: Akinobu Mita <amgta@yacht.ocn.ne.jp>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

drivers/base/node.c

@@ -38,11 +38,19 @@ static ssize_t node_read_meminfo(struct sys_device * dev, char * buf)
 	int n;
 	int nid = dev->id;
 	struct sysinfo i;
+	unsigned long inactive;
+	unsigned long active;
+	unsigned long free;
+
 	si_meminfo_node(&i, nid);
+	__get_zone_counts(&active, &inactive, &free, NODE_DATA(nid));
+
 	n = sprintf(buf, "\n"
 		       "Node %d MemTotal:     %8lu kB\n"
 		       "Node %d MemFree:      %8lu kB\n"
 		       "Node %d MemUsed:      %8lu kB\n"
+		       "Node %d Active:       %8lu kB\n"
+		       "Node %d Inactive:     %8lu kB\n"
 		       "Node %d HighTotal:    %8lu kB\n"
 		       "Node %d HighFree:     %8lu kB\n"
 		       "Node %d LowTotal:     %8lu kB\n"
@@ -50,6 +58,8 @@ static ssize_t node_read_meminfo(struct sys_device * dev, char * buf)
 		       nid, K(i.totalram),
 		       nid, K(i.freeram),
 		       nid, K(i.totalram - i.freeram),
+		       nid, K(active),
+		       nid, K(inactive),
 		       nid, K(i.totalhigh),
 		       nid, K(i.freehigh),
 		       nid, K(i.totalram - i.totalhigh),

include/linux/mmzone.h

@@ -272,6 +272,8 @@ typedef struct pglist_data {
 extern int numnodes;
 extern struct pglist_data *pgdat_list;
 
+void __get_zone_counts(unsigned long *active, unsigned long *inactive,
+			unsigned long *free, struct pglist_data *pgdat);
 void get_zone_counts(unsigned long *active, unsigned long *inactive,
 			unsigned long *free);
 void build_all_zonelists(void);

mm/page_alloc.c

@@ -961,18 +961,36 @@ unsigned long __read_page_state(unsigned offset)
 	return ret;
 }
 
+void __get_zone_counts(unsigned long *active, unsigned long *inactive,
+			unsigned long *free, struct pglist_data *pgdat)
+{
+	struct zone *zones = pgdat->node_zones;
+	int i;
+
+	*active = 0;
+	*inactive = 0;
+	*free = 0;
+	for (i = 0; i < MAX_NR_ZONES; i++) {
+		*active += zones[i].nr_active;
+		*inactive += zones[i].nr_inactive;
+		*free += zones[i].free_pages;
+	}
+}
+
 void get_zone_counts(unsigned long *active,
 		unsigned long *inactive, unsigned long *free)
 {
-	struct zone *zone;
+	struct pglist_data *pgdat;
 
 	*active = 0;
 	*inactive = 0;
 	*free = 0;
-	for_each_zone(zone) {
-		*active += zone->nr_active;
-		*inactive += zone->nr_inactive;
-		*free += zone->free_pages;
+	for_each_pgdat(pgdat) {
+		unsigned long l, m, n;
+		__get_zone_counts(&l, &m, &n, pgdat);
+		*active += l;
+		*inactive += m;
+		*free += n;
 	}
 }
 

mm/readahead.c

@@ -571,6 +571,6 @@ unsigned long max_sane_readahead(unsigned long nr)
 	unsigned long inactive;
 	unsigned long free;
 
-	get_zone_counts(&active, &inactive, &free);
+	__get_zone_counts(&active, &inactive, &free, NODE_DATA(numa_node_id()));
 	return min(nr, (inactive + free) / 2);
 }