mm/vmstat: add zone range overlapping check

There is a system thats node's pfns are overlapped as follows:

  -----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 <[email protected]>
Acked-by: Vlastimil Babka <[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: "Aneesh Kumar K.V" <[email protected]>
Cc: "Rafael J. Wysocki" <[email protected]>
Cc: Benjamin Herrenschmidt <[email protected]>
Cc: Paul Mackerras <[email protected]>
Cc: Michael Ellerman <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>

diff --git a/mm/vmstat.c b/mm/vmstat.c
index 5e43004828971e778a185ec69f2ef9710f085fb4..0a726e398cfda61ba6e7ae6c6fbf8d36c4a031bd 100644 (file)
--- 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;