diff --git a/include/linux/page-flags.h b/include/linux/page-flags.h
index d1bdbaaccc964..f060db808102c 100644
--- a/include/linux/page-flags.h
+++ b/include/linux/page-flags.h
@@ -945,15 +945,19 @@ PAGEFLAG_FALSE(HasHWPoisoned, has_hwpoisoned)
* mistaken for a page type value.
*/
-#define PAGE_TYPE_BASE 0xf0000000
-/* Reserve 0x0000007f to catch underflows of _mapcount */
-#define PAGE_MAPCOUNT_RESERVE -128
-#define PG_buddy 0x00000080
-#define PG_offline 0x00000100
-#define PG_table 0x00000200
-#define PG_guard 0x00000400
-#define PG_hugetlb 0x00000800
-#define PG_slab 0x00001000
+#define PAGE_TYPE_BASE 0x80000000
+/*
+ * Reserve 0xffff0000 - 0xfffffffe to catch _mapcount underflows and
+ * allow owners that set a type to reuse the lower 16 bit for their own
+ * purposes.
+ */
+#define PG_buddy 0x40000000
+#define PG_offline 0x20000000
+#define PG_table 0x10000000
+#define PG_guard 0x08000000
+#define PG_hugetlb 0x04008000
As Wang Wei points out, the 0 and 8 look too similar on my screen ;)
This should be
#define PG_hugetlb 0x04000000
--
Cheers,
David / dhildenb
