Index: linux-2.6/arch/sparc/mm/generic.c
===================================================================
--- linux-2.6.orig/arch/sparc/mm/generic.c
+++ linux-2.6/arch/sparc/mm/generic.c
@@ -73,6 +73,9 @@ int io_remap_pfn_range(struct vm_area_st
 	int space = GET_IOSPACE(pfn);
 	unsigned long offset = GET_PFN(pfn) << PAGE_SHIFT;
 
+	/* See comment in mm/memory.c remap_pfn_range */
+	vma->vm_flags |= VM_IO | VM_RESERVED;
+
 	prot = __pgprot(pg_iobits);
 	offset -= from;
 	dir = pgd_offset(mm, from);
Index: linux-2.6/arch/sparc64/mm/generic.c
===================================================================
--- linux-2.6.orig/arch/sparc64/mm/generic.c
+++ linux-2.6/arch/sparc64/mm/generic.c
@@ -127,6 +127,9 @@ int io_remap_pfn_range(struct vm_area_st
 	int space = GET_IOSPACE(pfn);
 	unsigned long offset = GET_PFN(pfn) << PAGE_SHIFT;
 
+	/* See comment in mm/memory.c remap_pfn_range */
+	vma->vm_flags |= VM_IO | VM_RESERVED;
+
 	prot = __pgprot(pg_iobits);
 	offset -= from;
 	dir = pgd_offset(mm, from);
Index: linux-2.6/mm/memory.c
===================================================================
--- linux-2.6.orig/mm/memory.c
+++ linux-2.6/mm/memory.c
@@ -1222,8 +1222,8 @@ int remap_pfn_range(struct vm_area_struc
 	 * rest of the world about it:
 	 *   VM_IO tells people not to look at these pages
 	 *	(accesses can have side effects).
-	 *   VM_RESERVED tells swapout not to try to touch
-	 *	this region.
+	 *   VM_RESERVED tells the core MM not to "manage" these pages
+         *	(e.g. refcount, mapcount, try to swap them out).
 	 */
 	vma->vm_flags |= VM_IO | VM_RESERVED;