diff --git a/include/linux/mm_types.h b/include/linux/mm_types.h
index 278eade2ad4c..ef09c4eef6d3 100644
--- a/include/linux/mm_types.h
+++ b/include/linux/mm_types.h
@@ -157,6 +157,11 @@ struct page {
 		 *
 		 * See page-flags.h for a list of page types which are currently
 		 * stored here.
+		 *
+		 * Owners of typed folios may reuse the lower 16 bit of the
+		 * head page page_type field after setting the page type,
+		 * but must reset these 16 bit to -1 before clearing the
+		 * page type.
 		 */
 		unsigned int page_type;
 
diff --git a/include/linux/page-flags.h b/include/linux/page-flags.h
index b041bc058fb1..d221a6a14764 100644
--- a/include/linux/page-flags.h
+++ b/include/linux/page-flags.h
@@ -941,16 +941,21 @@ PAGEFLAG_FALSE(HasHWPoisoned, has_hwpoisoned)
  */
 
 enum pagetype {
-	PG_buddy	= 0x00000080,
-	PG_offline	= 0x00000100,
-	PG_table	= 0x00000200,
-	PG_guard	= 0x00000400,
-	PG_hugetlb	= 0x00000800,
-	PG_slab		= 0x00001000,
+	PG_buddy	= 0x40000000,
+	PG_offline	= 0x20000000,
+	PG_table	= 0x10000000,
+	PG_guard	= 0x08000000,
+	PG_hugetlb	= 0x04000000,
+	PG_slab		= 0x02000000,
 
-	PAGE_TYPE_BASE	= 0xf0000000,
-	/* Reserve 0x0000007f to catch underflows of _mapcount */
-	PAGE_MAPCOUNT_RESERVE	= -128,
+	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.
+	 */
+	PAGE_MAPCOUNT_RESERVE	= ~0x0000ffff,
 };
 
 #define PageType(page, flag)						\