mm/page_alloc: correct highmem memory statistics

ZONE_MOVABLE could be treated as highmem so we need to consider it for
accurate statistics.  And, in following patches, ZONE_CMA will be
introduced and it can be treated as highmem, too.  So, instead of
manually adding stat of ZONE_MOVABLE, looping all zones and check
whether the zone is highmem or not and add stat of the zone which can be
treated as highmem.

Signed-off-by: Joonsoo Kim <[email protected]>
Reviewed-by: Aneesh Kumar K.V <[email protected]>
Cc: Rik van Riel <[email protected]>
Cc: Johannes Weiner <[email protected]>
Cc: Mel Gorman <[email protected]>
Cc: Laura Abbott <[email protected]>
Cc: Minchan Kim <[email protected]>
Cc: Marek Szyprowski <[email protected]>
Cc: Michal Nazarewicz <[email protected]>
Cc: Vlastimil Babka <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>

mm/page_alloc.c

@@ -3793,6 +3793,8 @@ void si_meminfo_node(struct sysinfo *val, int nid)
 {
 	int zone_type;		/* needs to be signed */
 	unsigned long managed_pages = 0;
+	unsigned long managed_highpages = 0;
+	unsigned long free_highpages = 0;
 	pg_data_t *pgdat = NODE_DATA(nid);
 
 	for (zone_type = 0; zone_type < MAX_NR_ZONES; zone_type++)
@@ -3801,12 +3803,19 @@ void si_meminfo_node(struct sysinfo *val, int nid)
 	val->sharedram = node_page_state(nid, NR_SHMEM);
 	val->freeram = node_page_state(nid, NR_FREE_PAGES);
 #ifdef CONFIG_HIGHMEM
-	val->totalhigh = pgdat->node_zones[ZONE_HIGHMEM].managed_pages;
-	val->freehigh = zone_page_state(&pgdat->node_zones[ZONE_HIGHMEM],
-			NR_FREE_PAGES);
+	for (zone_type = 0; zone_type < MAX_NR_ZONES; zone_type++) {
+		struct zone *zone = &pgdat->node_zones[zone_type];
+
+		if (is_highmem(zone)) {
+			managed_highpages += zone->managed_pages;
+			free_highpages += zone_page_state(zone, NR_FREE_PAGES);
+		}
+	}
+	val->totalhigh = managed_highpages;
+	val->freehigh = free_highpages;
 #else
-	val->totalhigh = 0;
-	val->freehigh = 0;
+	val->totalhigh = managed_highpages;
+	val->freehigh = free_highpages;
 #endif
 	val->mem_unit = PAGE_SIZE;
 }