[PATCH 4/6] mm/vmstat: add zone range overlapping check

[js1304]

From: Joonsoo Kim <iamjoonsoo.kim@xxxxxxx>

There is a system that node's pfn are overlapped like as following.

-----pfn-------->
N0 N1 N2 N0 N1 N2

Therefore, we need to care this overlapping when iterating pfn range.

There are two places in vmstat.c that iterates pfn range and
they don't consider this overlapping. Add it.

Without this patch, above system could over count pageblock number
on a zone.

Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@xxxxxxx>
---
 mm/vmstat.c | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/mm/vmstat.c b/mm/vmstat.c
index 5e43004..0a726e3 100644
--- a/mm/vmstat.c
+++ b/mm/vmstat.c
@@ -1010,6 +1010,9 @@ static void pagetypeinfo_showblockcount_print(struct seq_file *m,
 		if (!memmap_valid_within(pfn, page, zone))
 			continue;
 
+		if (page_zone(page) != zone)
+			continue;
+
 		mtype = get_pageblock_migratetype(page);
 
 		if (mtype < MIGRATE_TYPES)
@@ -1076,6 +1079,10 @@ static void pagetypeinfo_showmixedcount_print(struct seq_file *m,
 				continue;
 
 			page = pfn_to_page(pfn);
+
+			if (page_zone(page) != zone)
+				continue;
+
 			if (PageBuddy(page)) {
 				pfn += (1UL << page_order(page)) - 1;
 				continue;
-- 
1.9.1