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 <iamjoonsoo.kim@lge.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Rik van Riel <riel@redhat.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Laura Abbott <lauraa@codeaurora.org>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Marek Szyprowski <m.szyprowski@samsung.com>
Cc: Michal Nazarewicz <mina86@mina86.com>
Cc: "Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com>
Cc: "Rafael J. Wysocki" <rjw@rjwysocki.net>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

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;