diff --git a/sys/sys/mman.h b/sys/sys/mman.h
index d846911bcc43..658c2b458ea9 100644
--- a/sys/sys/mman.h
+++ b/sys/sys/mman.h
@@ -31,7 +31,7 @@
  * SUCH DAMAGE.
  *
  *	@(#)mman.h	8.2 (Berkeley) 1/9/95
- * $Id: mman.h,v 1.12 1996/03/11 02:09:09 hsu Exp $
+ * $Id: mman.h,v 1.13 1996/05/19 07:36:41 dyson Exp $
  */
 
 #ifndef _SYS_MMAN_H_
@@ -83,6 +83,7 @@
 #define	MADV_SEQUENTIAL	2	/* expect sequential page references */
 #define	MADV_WILLNEED	3	/* will need these pages */
 #define	MADV_DONTNEED	4	/* dont need these pages */
+#define	MADV_FREE	5	/* dont need these pages, and junk contents */
 
 /*
  * Return bits from mincore
diff --git a/sys/vm/swap_pager.c b/sys/vm/swap_pager.c
index 4feebd56415e..37427ec2fe2a 100644
--- a/sys/vm/swap_pager.c
+++ b/sys/vm/swap_pager.c
@@ -39,7 +39,7 @@
  * from: Utah $Hdr: swap_pager.c 1.4 91/04/30$
  *
  *	@(#)swap_pager.c	8.9 (Berkeley) 3/21/94
- * $Id: swap_pager.c,v 1.65 1996/05/03 21:01:47 phk Exp $
+ * $Id: swap_pager.c,v 1.66 1996/05/18 03:37:32 dyson Exp $
  */
 
 /*
@@ -438,6 +438,32 @@ swap_pager_freespace(object, start, size)
 	splx(s);
 }
 
+/*
+ * same as freespace, but don't free, just force a DMZ next time
+ */
+void
+swap_pager_dmzspace(object, start, size)
+	vm_object_t object;
+	vm_pindex_t start;
+	vm_size_t size;
+{
+	vm_pindex_t i;
+	int s;
+
+	s = splbio();
+	for (i = start; i < start + size; i += 1) {
+		int valid;
+		daddr_t *addr = swap_pager_diskaddr(object, i, &valid);
+
+		if (addr && *addr != SWB_EMPTY) {
+			if (valid) {
+				swap_pager_setvalid(object, i, 0);
+			}
+		}
+	}
+	splx(s);
+}
+
 static void
 swap_pager_free_swap(object)
 	vm_object_t object;
diff --git a/sys/vm/swap_pager.h b/sys/vm/swap_pager.h
index 3fdd44e7a6d0..5240eb5e6bdd 100644
--- a/sys/vm/swap_pager.h
+++ b/sys/vm/swap_pager.h
@@ -36,7 +36,7 @@
  * SUCH DAMAGE.
  *
  *	from: @(#)swap_pager.h	7.1 (Berkeley) 12/5/90
- *	$Id: swap_pager.h,v 1.14 1996/01/30 23:02:29 mpp Exp $
+ *	$Id: swap_pager.h,v 1.15 1996/03/03 21:11:06 dyson Exp $
  */
 
 /*
@@ -73,6 +73,7 @@ int swap_pager_swp_alloc __P((vm_object_t, int));
 void swap_pager_copy __P((vm_object_t, vm_pindex_t, vm_object_t,
 	vm_pindex_t, vm_pindex_t));
 void swap_pager_freespace __P((vm_object_t, vm_pindex_t, vm_size_t));
+void swap_pager_dmzspace __P((vm_object_t, vm_pindex_t, vm_size_t));
 void swap_pager_swap_init __P((void));
 #endif
 
diff --git a/sys/vm/vm_map.c b/sys/vm/vm_map.c
index 89f4e87d30d6..f0339e813f78 100644
--- a/sys/vm/vm_map.c
+++ b/sys/vm/vm_map.c
@@ -61,7 +61,7 @@
  * any improvements or extensions that they make and grant Carnegie the
  * rights to redistribute these changes.
  *
- * $Id: vm_map.c,v 1.45 1996/05/18 03:37:43 dyson Exp $
+ * $Id: vm_map.c,v 1.46 1996/05/19 07:36:46 dyson Exp $
  */
 
 /*
@@ -1225,6 +1225,7 @@ vm_map_madvise(map, pmap, start, end, advise)
 	 * Right now, we could handle DONTNEED and WILLNEED with common code.
 	 * They are mostly the same, except for the potential async reads (NYI).
 	 */
+	case MADV_FREE:
 	case MADV_DONTNEED:
 			{
 				vm_pindex_t pindex;
diff --git a/sys/vm/vm_object.c b/sys/vm/vm_object.c
index 83ee0cd2fb31..da2c62c4cdec 100644
--- a/sys/vm/vm_object.c
+++ b/sys/vm/vm_object.c
@@ -61,7 +61,7 @@
  * any improvements or extensions that they make and grant Carnegie the
  * rights to redistribute these changes.
  *
- * $Id: vm_object.c,v 1.71 1996/05/21 05:26:27 dyson Exp $
+ * $Id: vm_object.c,v 1.72 1996/05/21 17:13:31 dyson Exp $
  */
 
 /*
@@ -709,7 +709,9 @@ vm_object_madvise(object, pindex, count, advise)
 		if (advise == MADV_WILLNEED) {
 			if (m->queue != PQ_ACTIVE)
 				vm_page_activate(m);
-		} else if (advise == MADV_DONTNEED) {
+		} else if ((advise == MADV_DONTNEED) ||
+			((advise == MADV_FREE) &&
+				((object->type != OBJT_DEFAULT) && (object->type != OBJT_SWAP)))) {
 			/*
 			 * If the upper level VM system doesn't think that
 			 * the page is dirty, check the pmap layer.
@@ -732,64 +734,18 @@ vm_object_madvise(object, pindex, count, advise)
 				vm_page_protect(m, VM_PROT_NONE);
 				vm_page_deactivate(m);
 			}
+		} else if (advise == MADV_FREE) {
+			/*
+			 * Force a demand-zero on next ref
+			 */
+			if (object->type == OBJT_SWAP)
+				swap_pager_dmzspace(object, m->pindex, 1);
+			vm_page_protect(m, VM_PROT_NONE);
+			vm_page_free(m);
 		}
 	}	
 }
 
-/*
- *	vm_object_copy:
- *
- *	Create a new object which is a copy of an existing
- *	object, and mark all of the pages in the existing
- *	object 'copy-on-write'.  The new object has one reference.
- *	Returns the new object.
- *
- *	May defer the copy until later if the object is not backed
- *	up by a non-default pager.
- *
- */
-void
-vm_object_copy(src_object, src_offset,
-    dst_object, dst_offset, src_needs_copy)
-	register vm_object_t src_object;
-	vm_pindex_t src_offset;
-	vm_object_t *dst_object;/* OUT */
-	vm_pindex_t *dst_offset;/* OUT */
-	boolean_t *src_needs_copy;	/* OUT */
-{
-	if (src_object == NULL) {
-		/*
-		 * Nothing to copy
-		 */
-		*dst_object = NULL;
-		*dst_offset = 0;
-		*src_needs_copy = FALSE;
-		return;
-	}
-
-	/*
-	 * Try to collapse the object before copying it.
-	 */
-	if (src_object->handle == NULL &&
-	    (src_object->type == OBJT_DEFAULT ||
-	     src_object->type == OBJT_SWAP))
-		vm_object_collapse(src_object);
-
-
-	/*
-	 * Make another reference to the object
-	 */
-	src_object->ref_count++;
-	*dst_object = src_object;
-	*dst_offset = src_offset;
-
-	/*
-	 * Must make a shadow when write is desired
-	 */
-	*src_needs_copy = TRUE;
-	return;
-}
-
 /*
  *	vm_object_shadow:
  *