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-rw-r--r--mm/mmzone.c15
-rw-r--r--mm/vmstat.c19
2 files changed, 19 insertions, 15 deletions
diff --git a/mm/mmzone.c b/mm/mmzone.c
index 16ce8b955dcf..f5b7d1760213 100644
--- a/mm/mmzone.c
+++ b/mm/mmzone.c
@@ -6,6 +6,7 @@
#include <linux/stddef.h>
+#include <linux/mm.h>
#include <linux/mmzone.h>
#include <linux/module.h>
@@ -72,3 +73,17 @@ struct zoneref *next_zones_zonelist(struct zoneref *z,
*zone = zonelist_zone(z);
return z;
}
+
+#ifdef CONFIG_ARCH_HAS_HOLES_MEMORYMODEL
+int memmap_valid_within(unsigned long pfn,
+ struct page *page, struct zone *zone)
+{
+ if (page_to_pfn(page) != pfn)
+ return 0;
+
+ if (page_zone(page) != zone)
+ return 0;
+
+ return 1;
+}
+#endif /* CONFIG_ARCH_HAS_HOLES_MEMORYMODEL */
diff --git a/mm/vmstat.c b/mm/vmstat.c
index 66f6130976cb..74d66dba0cbe 100644
--- a/mm/vmstat.c
+++ b/mm/vmstat.c
@@ -509,22 +509,11 @@ static void pagetypeinfo_showblockcount_print(struct seq_file *m,
continue;
page = pfn_to_page(pfn);
-#ifdef CONFIG_ARCH_FLATMEM_HAS_HOLES
- /*
- * Ordinarily, memory holes in flatmem still have a valid
- * memmap for the PFN range. However, an architecture for
- * embedded systems (e.g. ARM) can free up the memmap backing
- * holes to save memory on the assumption the memmap is
- * never used. The page_zone linkages are then broken even
- * though pfn_valid() returns true. Skip the page if the
- * linkages are broken. Even if this test passed, the impact
- * is that the counters for the movable type are off but
- * fragmentation monitoring is likely meaningless on small
- * systems.
- */
- if (page_zone(page) != zone)
+
+ /* Watch for unexpected holes punched in the memmap */
+ if (!memmap_valid_within(pfn, page, zone))
continue;
-#endif
+
mtype = get_pageblock_migratetype(page);
if (mtype < MIGRATE_TYPES)