NOTE: libkvm, w, ps, 'top', and any other utility which depends on struct

      proc or any VM system structure will have to be rebuilt!!!

Much needed overhaul of the VM system. Included in this first round of
changes:

1) Improved pager interfaces: init, alloc, dealloc, getpages, putpages,
   haspage, and sync operations are supported. The haspage interface now
   provides information about clusterability. All pager routines now take
   struct vm_object's instead of "pagers".

2) Improved data structures. In the previous paradigm, there is constant
   confusion caused by pagers being both a data structure ("allocate a
   pager") and a collection of routines. The idea of a pager structure has
   escentially been eliminated. Objects now have types, and this type is
   used to index the appropriate pager. In most cases, items in the pager
   structure were duplicated in the object data structure and thus were
   unnecessary. In the few cases that remained, a un_pager structure union
   was created in the object to contain these items.

3) Because of the cleanup of #1 & #2, a lot of unnecessary layering can now
   be removed. For instance, vm_object_enter(), vm_object_lookup(),
   vm_object_remove(), and the associated object hash list were some of the
   things that were removed.

4) simple_lock's removed. Discussion with several people reveals that the
   SMP locking primitives used in the VM system aren't likely the mechanism
   that we'll be adopting. Even if it were, the locking that was in the code
   was very inadequate and would have to be mostly re-done anyway. The
   locking in a uni-processor kernel was a no-op but went a long way toward
   making the code difficult to read and debug.

5) Places that attempted to kludge-up the fact that we don't have kernel
   thread support have been fixed to reflect the reality that we are really
   dealing with processes, not threads. The VM system didn't have complete
   thread support, so the comments and mis-named routines were just wrong.
   We now use tsleep and wakeup directly in the lock routines, for instance.

6) Where appropriate, the pagers have been improved, especially in the
   pager_alloc routines. Most of the pager_allocs have been rewritten and
   are now faster and easier to maintain.

7) The pagedaemon pageout clustering algorithm has been rewritten and
   now tries harder to output an even number of pages before and after
   the requested page. This is sort of the reverse of the ideal pagein
   algorithm and should provide better overall performance.

8) Unnecessary (incorrect) casts to caddr_t in calls to tsleep & wakeup
   have been removed. Some other unnecessary casts have also been removed.

9) Some almost useless debugging code removed.

10) Terminology of shadow objects vs. backing objects straightened out.
    The fact that the vm_object data structure escentially had this
    backwards really confused things. The use of "shadow" and "backing
    object" throughout the code is now internally consistent and correct
    in the Mach terminology.

11) Several minor bug fixes, including one in the vm daemon that caused
    0 RSS objects to not get purged as intended.

12) A "default pager" has now been created which cleans up the transition
    of objects to the "swap" type. The previous checks throughout the code
    for swp->pg_data != NULL were really ugly. This change also provides
    the rudiments for future backing of "anonymous" memory by something
    other than the swap pager (via the vnode pager, for example), and it
    allows the decision about which of these pagers to use to be made
    dynamically (although will need some additional decision code to do
    this, of course).

13) (dyson) MAP_COPY has been deprecated and the corresponding "copy
    object" code has been removed. MAP_COPY was undocumented and non-
    standard. It was furthermore broken in several ways which caused its
    behavior to degrade to MAP_PRIVATE. Binaries that use MAP_COPY will
    continue to work correctly, but via the slightly different semantics
    of MAP_PRIVATE.

14) (dyson) Sharing maps have been removed. It's marginal usefulness in a
    threads design can be worked around in other ways. Both #12 and #13
    were done to simplify the code and improve readability and maintain-
    ability. (As were most all of these changes)

TODO:

1) Rewrite most of the vnode pager to use VOP_GETPAGES/PUTPAGES. Doing
   this will reduce the vnode pager to a mere fraction of its current size.

2) Rewrite vm_fault and the swap/vnode pagers to use the clustering
   information provided by the new haspage pager interface. This will
   substantially reduce the overhead by eliminating a large number of
   VOP_BMAP() calls. The VOP_BMAP() filesystem interface should be
   improved to provide both a "behind" and "ahead" indication of
   contiguousness.

3) Implement the extended features of pager_haspage in swap_pager_haspage().
   It currently just says 0 pages ahead/behind.

4) Re-implement the swap device (swstrategy) in a more elegant way, perhaps
   via a much more general mechanism that could also be used for disk
   striping of regular filesystems.

5) Do something to improve the architecture of vm_object_collapse(). The
   fact that it makes calls into the swap pager and knows too much about
   how the swap pager operates really bothers me. It also doesn't allow
   for collapsing of non-swap pager objects ("unnamed" objects backed by
   other pagers).

1 files changed, 177 insertions, 569 deletions

diff --git a/sys/vm/vm_object.c b/sys/vm/vm_object.c
index 3c601b4..834f28c 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 1.47.2.1 1995/06/04 13:53:25 davidg Exp $
+ * $Id: vm_object.c,v 1.48 1995/06/11 19:31:53 rgrimes Exp $
  */
 
 /*
@@ -81,10 +81,9 @@
 #include <vm/vm_pageout.h>
 #include <vm/vm_pager.h>
 #include <vm/swap_pager.h>
-#include <vm/vnode_pager.h>
 #include <vm/vm_kern.h>
 
-static void _vm_object_allocate(vm_size_t, vm_object_t);
+static void _vm_object_allocate(objtype_t, vm_size_t, vm_object_t);
 
 
 /*
@@ -119,41 +118,34 @@ struct vm_object kmem_object_store;
 
 int vm_object_cache_max;
 
-#define	VM_OBJECT_HASH_COUNT	1021
-
-struct vm_object_hash_head vm_object_hashtable[VM_OBJECT_HASH_COUNT];
-#define OBJECT_HASH(pager) ((unsigned long)(pager) % VM_OBJECT_HASH_COUNT)
-
 long object_collapses;
 long object_bypasses;
 
 static void
-_vm_object_allocate(size, object)
+_vm_object_allocate(type, size, object)
+	objtype_t type;
 	vm_size_t size;
 	register vm_object_t object;
 {
 	TAILQ_INIT(&object->memq);
-	TAILQ_INIT(&object->reverse_shadow_head);
+	TAILQ_INIT(&object->shadow_head);
 
+	object->type = type;
 	object->size = size;
 	object->ref_count = 1;
-	vm_object_lock_init(object);
-	object->flags = OBJ_INTERNAL;	/* pager will reset */
+	object->flags = 0;
 	object->paging_in_progress = 0;
 	object->resident_page_count = 0;
-
-	object->pager = NULL;
+	object->pg_data = NULL;
+	object->handle = NULL;
 	object->paging_offset = 0;
-	object->shadow = NULL;
-	object->shadow_offset = (vm_offset_t) 0;
-	object->copy = NULL;
+	object->backing_object = NULL;
+	object->backing_object_offset = (vm_offset_t) 0;
 
 	object->last_read = 0;
 
-	simple_lock(&vm_object_list_lock);
 	TAILQ_INSERT_TAIL(&vm_object_list, object, object_list);
 	vm_object_count++;
-	simple_unlock(&vm_object_list_lock);
 }
 
 /*
@@ -169,22 +161,17 @@ vm_object_init(vm_offset_t nothing)
 	TAILQ_INIT(&vm_object_cached_list);
 	TAILQ_INIT(&vm_object_list);
 	vm_object_count = 0;
-	simple_lock_init(&vm_cache_lock);
-	simple_lock_init(&vm_object_list_lock);
-
+	
 	vm_object_cache_max = 84;
 	if (cnt.v_page_count > 1000)
 		vm_object_cache_max += (cnt.v_page_count - 1000) / 4;
 
-	for (i = 0; i < VM_OBJECT_HASH_COUNT; i++)
-		LIST_INIT(&vm_object_hashtable[i]);
-
 	kernel_object = &kernel_object_store;
-	_vm_object_allocate(VM_MAX_KERNEL_ADDRESS - VM_MIN_KERNEL_ADDRESS,
+	_vm_object_allocate(OBJT_DEFAULT, VM_MAX_KERNEL_ADDRESS - VM_MIN_KERNEL_ADDRESS,
 	    kernel_object);
 
 	kmem_object = &kmem_object_store;
-	_vm_object_allocate(VM_MAX_KERNEL_ADDRESS - VM_MIN_KERNEL_ADDRESS,
+	_vm_object_allocate(OBJT_DEFAULT, VM_MAX_KERNEL_ADDRESS - VM_MIN_KERNEL_ADDRESS,
 	    kmem_object);
 }
 
@@ -195,7 +182,8 @@ vm_object_init(vm_offset_t nothing)
  */
 
 vm_object_t
-vm_object_allocate(size)
+vm_object_allocate(type, size)
+	objtype_t type;
 	vm_size_t size;
 {
 	register vm_object_t result;
@@ -204,7 +192,7 @@ vm_object_allocate(size)
 	    malloc((u_long) sizeof *result, M_VMOBJ, M_WAITOK);
 
 
-	_vm_object_allocate(size, result);
+	_vm_object_allocate(type, size, result);
 
 	return (result);
 }
@@ -222,9 +210,13 @@ vm_object_reference(object)
 	if (object == NULL)
 		return;
 
-	vm_object_lock(object);
+	if (object->ref_count == 0) {
+		if ((object->flags & OBJ_CANPERSIST) == 0)
+			panic("vm_object_reference: non-persistent object with 0 ref_count");
+		TAILQ_REMOVE(&vm_object_cached_list, object, cached_list);
+		vm_object_cached--;
+	}
 	object->ref_count++;
-	vm_object_unlock(object);
 }
 
 /*
@@ -243,7 +235,6 @@ vm_object_deallocate(object)
 	vm_object_t object;
 {
 	vm_object_t temp;
-	vm_pager_t pager;
 
 	while (object != NULL) {
 
@@ -251,26 +242,21 @@ vm_object_deallocate(object)
 			panic("vm_object_deallocate: object deallocated too many times");
 
 		/*
-		 * The cache holds a reference (uncounted) to the object; we
-		 * must lock it before removing the object.
-		 */
-
-		vm_object_cache_lock();
-
-		/*
 		 * Lose the reference
 		 */
-		vm_object_lock(object);
-
 		object->ref_count--;
 
 		if (object->ref_count != 0) {
 			if ((object->ref_count == 1) &&
-			    (object->flags & OBJ_INTERNAL)) {
+			    (object->handle == NULL) &&
+			    (object->type == OBJT_DEFAULT ||
+			     object->type == OBJT_SWAP)) {
 				vm_object_t robject;
-				robject = object->reverse_shadow_head.tqh_first;
+				robject = object->shadow_head.tqh_first;
 				if ((robject != NULL) &&
-				    (robject->flags & OBJ_INTERNAL)) {
+				    (robject->handle == NULL) &&
+				    (robject->type == OBJT_DEFAULT ||
+				     robject->type == OBJT_SWAP)) {
 					int s;
 					robject->ref_count += 2;
 					object->ref_count += 2;
@@ -293,33 +279,24 @@ vm_object_deallocate(object)
 					object->ref_count -= 2;
 					robject->ref_count -= 2;
 					if( robject->ref_count == 0) {
-						vm_object_unlock(object);
-						vm_object_cache_unlock();
 						robject->ref_count += 1;
 						object = robject;
 						continue;
 					}
-					vm_object_cache_unlock();
-					vm_object_unlock(object);
-					vm_object_lock(robject);
 					vm_object_collapse(robject);
 					return;
 				}
 			}
-			vm_object_unlock(object);
 			/*
 			 * If there are still references, then we are done.
 			 */
-			vm_object_cache_unlock();
 			return;
 		}
 
-		pager = object->pager;
-
-		if (pager && pager->pg_type == PG_VNODE) {
-			vn_pager_t vnp = (vn_pager_t) pager->pg_data;
+		if (object->type == OBJT_VNODE) {
+			struct vnode *vp = object->handle;
 
-			vnp->vnp_vp->v_flag &= ~VTEXT;
+			vp->v_flag &= ~VTEXT;
 		}
 
 		/*
@@ -328,13 +305,10 @@ vm_object_deallocate(object)
 		 */
 		if (object->flags & OBJ_CANPERSIST) {
 			if (object->resident_page_count != 0) {
-				vm_object_page_clean(object, 0, 0 ,TRUE);
+				vm_object_page_clean(object, 0, 0 ,TRUE, TRUE);
 				TAILQ_INSERT_TAIL(&vm_object_cached_list, object,
 				    cached_list);
 				vm_object_cached++;
-				vm_object_cache_unlock();
-
-				vm_object_unlock(object);
 
 				vm_object_cache_trim();
 				return;
@@ -344,16 +318,13 @@ vm_object_deallocate(object)
 		}
 
 		/*
-		 * Make sure no one can look us up now.
+		 * Make sure no one uses us.
 		 */
 		object->flags |= OBJ_DEAD;
-		if ((object->flags & OBJ_INTERNAL) == 0)
-			vm_object_remove(pager);
-		vm_object_cache_unlock();
 
-		temp = object->shadow;
+		temp = object->backing_object;
 		if (temp)
-			TAILQ_REMOVE(&temp->reverse_shadow_head, object, reverse_shadow_list);
+			TAILQ_REMOVE(&temp->shadow_head, object, shadow_list);
 		vm_object_terminate(object);
 		/* unlocks and deallocates object */
 		object = temp;
@@ -371,28 +342,16 @@ vm_object_terminate(object)
 	register vm_object_t object;
 {
 	register vm_page_t p, next;
-	vm_object_t shadow_object;
+	vm_object_t backing_object;
 	int s;
 
 	/*
-	 * Detach the object from its shadow if we are the shadow's copy.
-	 */
-	if ((shadow_object = object->shadow) != NULL) {
-		vm_object_lock(shadow_object);
-		if (shadow_object->copy == object)
-			shadow_object->copy = NULL;
-		vm_object_unlock(shadow_object);
-	}
-
-	/*
 	 * wait for the pageout daemon to be done with the object
 	 */
 	s = splhigh();
 	while (object->paging_in_progress) {
-		vm_object_unlock(object);
 		object->flags |= OBJ_PIPWNT;
-		tsleep((caddr_t) object, PVM, "objtrm", 0);
-		vm_object_lock(object);
+		tsleep(object, PVM, "objtrm", 0);
 	}
 	splx(s);
 
@@ -403,13 +362,11 @@ vm_object_terminate(object)
 	 * Clean and free the pages, as appropriate. All references to the
 	 * object are gone, so we don't need to lock it.
 	 */
-	if (object->pager && (object->pager->pg_type == PG_VNODE)) {
-		vn_pager_t vnp = object->pager->pg_data;
-		struct vnode *vp;
+	if (object->type == OBJT_VNODE) {
+		struct vnode *vp = object->handle;
 
-		vp = vnp->vnp_vp;
 		VOP_LOCK(vp);
-		(void) _vm_object_page_clean(object, 0, 0, TRUE);
+		vm_object_page_clean(object, 0, 0, TRUE, FALSE);
 		vinvalbuf(vp, V_SAVE, NOCRED, NULL, 0, 0);
 		VOP_UNLOCK(vp);
 	}
@@ -419,27 +376,20 @@ vm_object_terminate(object)
 	 * from paging queues.
 	 */
 	while ((p = object->memq.tqh_first) != NULL) {
-		VM_PAGE_CHECK(p);
-		vm_page_lock_queues();
 		if (p->flags & PG_BUSY)
 			printf("vm_object_terminate: freeing busy page\n");
 		PAGE_WAKEUP(p);
 		vm_page_free(p);
 		cnt.v_pfree++;
-		vm_page_unlock_queues();
 	}
-	vm_object_unlock(object);
 
 	/*
 	 * Let the pager know object is dead.
 	 */
-	if (object->pager != NULL)
-		vm_pager_deallocate(object->pager);
+	vm_pager_deallocate(object);
 
-	simple_lock(&vm_object_list_lock);
 	TAILQ_REMOVE(&vm_object_list, object, object_list);
 	vm_object_count--;
-	simple_unlock(&vm_object_list_lock);
 
 	wakeup(object);
 
@@ -461,11 +411,12 @@ vm_object_terminate(object)
  */
 
 void
-_vm_object_page_clean(object, start, end, syncio)
+vm_object_page_clean(object, start, end, syncio, lockflag)
 	vm_object_t object;
 	vm_offset_t start;
 	vm_offset_t end;
 	boolean_t syncio;
+	boolean_t lockflag;
 {
 	register vm_page_t p;
 	register vm_offset_t tstart, tend;
@@ -473,10 +424,16 @@ _vm_object_page_clean(object, start, end, syncio)
 	int pgcount, s;
 	int allclean;
 	int entireobj;
+	struct vnode *vp;
 
-	if (object->pager == NULL || (object->flags & OBJ_WRITEABLE) == 0)
+	if (object->type != OBJT_VNODE || (object->flags & OBJ_WRITEABLE) == 0)
 		return;
 
+	vp = object->handle;
+
+	if (lockflag)
+		VOP_LOCK(vp);
+
 	if (start != end) {
 		start = trunc_page(start);
 		end = round_page(end);
@@ -495,17 +452,6 @@ startover:
 		object->flags &= ~OBJ_WRITEABLE;
 		entireobj = 1;
 	}
-	/*
-	 * Wait until potential collapse operation is complete
-	 */
-	if (object->flags & OBJ_INTERNAL) {
-		s = splhigh();
-		while (object->paging_in_progress) {
-			object->flags |= OBJ_PIPWNT;
-			tsleep(object, PVM, "objpcw", 0);
-		}
-		splx(s);
-	}
 
 	pgcount = object->resident_page_count;
 
@@ -543,6 +489,8 @@ startover:
 			pass = 1;
 			goto startover;
 		}
+		if (lockflag)
+			VOP_UNLOCK(vp);
 		return;
 	}
 
@@ -599,50 +547,9 @@ startover:
 			object->flags &= ~OBJ_WRITEABLE;
 		goto startover;
 	}
-	return;
-}
-
-
-void
-vm_object_page_clean(object, start, end, syncio)
-	register vm_object_t object;
-	register vm_offset_t start;
-	register vm_offset_t end;
-	boolean_t syncio;
-{
-	if (object->pager && (object->flags & OBJ_WRITEABLE) &&
-		(object->pager->pg_type == PG_VNODE)) {
-		vn_pager_t vnp = (vn_pager_t) object->pager->pg_data;
-		struct vnode *vp;
-
-		vp = vnp->vnp_vp;
-		VOP_LOCK(vp);
-		_vm_object_page_clean(object, start, end, syncio);
+	if (lockflag)
 		VOP_UNLOCK(vp);
-	} else {
-		_vm_object_page_clean(object, start, end, syncio);
-	}
-}
-
-void
-vm_object_cache_clean()
-{
-	vm_object_t object;
-	vm_object_cache_lock();
-	while(1) {
-		object = vm_object_cached_list.tqh_first;
-		while( object) {
-			if( (object->flags & OBJ_WRITEABLE) &&
-				object->pager &&
-				object->pager->pg_type == PG_VNODE) {
-				vm_object_page_clean(object, 0, 0, 0);
-				goto loop;
-			}
-			object = object->cached_list.tqe_next;
-		}
-		return;
-loop:
-	}
+	return;
 }
 
 /*
@@ -661,9 +568,7 @@ vm_object_deactivate_pages(object)
 
 	for (p = object->memq.tqh_first; p != NULL; p = next) {
 		next = p->listq.tqe_next;
-		vm_page_lock_queues();
 		vm_page_deactivate(p);
-		vm_page_unlock_queues();
 	}
 }
 
@@ -675,19 +580,12 @@ vm_object_cache_trim()
 {
 	register vm_object_t object;
 
-	vm_object_cache_lock();
 	while (vm_object_cached > vm_object_cache_max) {
 		object = vm_object_cached_list.tqh_first;
-		vm_object_cache_unlock();
-
-		if (object != vm_object_lookup(object->pager))
-			panic("vm_object_cache_trim: I'm sooo confused.");
 
+		vm_object_reference(object);
 		pager_cache(object, FALSE);
-
-		vm_object_cache_lock();
 	}
-	vm_object_cache_unlock();
 }
 
 
@@ -711,14 +609,12 @@ vm_object_pmap_copy(object, start, end)
 	if (object == NULL)
 		return;
 
-	vm_object_lock(object);
 	for (p = object->memq.tqh_first; p != NULL; p = p->listq.tqe_next) {
 		if ((start <= p->offset) && (p->offset < end)) {
 			vm_page_protect(p, VM_PROT_READ);
 			p->flags |= PG_COPYONWRITE;
 		}
 	}
-	vm_object_unlock(object);
 }
 
 /*
@@ -742,14 +638,13 @@ vm_object_pmap_remove(object, start, end)
 		return;
 	++object->paging_in_progress;
 
-	vm_object_lock(object);
 again:
 	for (p = object->memq.tqh_first; p != NULL; p = p->listq.tqe_next) {
 		if ((start <= p->offset) && (p->offset < end)) {
 			s = splhigh();
 			if ((p->flags & PG_BUSY) || p->busy) {
 				p->flags |= PG_WANTED;
-				tsleep((caddr_t) p, PVM, "vmopmr", 0);
+				tsleep(p, PVM, "vmopmr", 0);
 				splx(s);
 				goto again;
 			}
@@ -757,7 +652,6 @@ again:
 			vm_page_protect(p, VM_PROT_NONE);
 		}
 	}
-	vm_object_unlock(object);
 	vm_object_pip_wakeup(object);
 }
 
@@ -797,160 +691,37 @@ vm_object_copy(src_object, src_offset, size,
 		*src_needs_copy = FALSE;
 		return;
 	}
-	/*
-	 * If the object's pager is null_pager or the default pager, we don't
-	 * have to make a copy of it.  Instead, we set the needs copy flag and
-	 * make a shadow later.
-	 */
-
-	vm_object_lock(src_object);
 
 	/*
 	 * 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);
 
-	vm_object_collapse(src_object);
-
-	if (src_object->pager == NULL ||
-	    (src_object->flags & OBJ_INTERNAL)) {
-
-		/*
-		 * Make another reference to the object
-		 */
-		src_object->ref_count++;
-
-		/*
-		 * Mark all of the pages copy-on-write.
-		 */
-		for (p = src_object->memq.tqh_first; p; p = p->listq.tqe_next)
-			if (src_offset <= p->offset &&
-			    p->offset < src_offset + size)
-				p->flags |= PG_COPYONWRITE;
-		vm_object_unlock(src_object);
-
-		*dst_object = src_object;
-		*dst_offset = src_offset;
-
-		/*
-		 * Must make a shadow when write is desired
-		 */
-		*src_needs_copy = TRUE;
-		return;
-	}
-	/*
-	 * If the object has a pager, the pager wants to see all of the
-	 * changes.  We need a copy-object for the changed pages.
-	 *
-	 * If there is a copy-object, and it is empty, no changes have been made
-	 * to the object since the copy-object was made.  We can use the same
-	 * copy- object.
-	 */
-
-Retry1:
-	old_copy = src_object->copy;
-	if (old_copy != NULL) {
-		/*
-		 * Try to get the locks (out of order)
-		 */
-		if (!vm_object_lock_try(old_copy)) {
-			vm_object_unlock(src_object);
-
-			/* should spin a bit here... */
-			tsleep((caddr_t) old_copy, PVM, "cpylck", 1);
-			vm_object_lock(src_object);
-			goto Retry1;
-		}
-		if (old_copy->resident_page_count == 0 &&
-		    old_copy->pager == NULL) {
-			/*
-			 * Return another reference to the existing
-			 * copy-object.
-			 */
-			old_copy->ref_count++;
-			vm_object_unlock(old_copy);
-			vm_object_unlock(src_object);
-			*dst_object = old_copy;
-			*dst_offset = src_offset;
-			*src_needs_copy = FALSE;
-			return;
-		}
-		vm_object_unlock(old_copy);
-	}
-	vm_object_unlock(src_object);
-
-	/*
-	 * If the object has a pager, the pager wants to see all of the
-	 * changes.  We must make a copy-object and put the changed pages
-	 * there.
-	 *
-	 * The copy-object is always made large enough to completely shadow the
-	 * original object, since it may have several users who want to shadow
-	 * the original object at different points.
-	 */
-
-	new_copy = vm_object_allocate(src_object->size);
-
-Retry2:
-	vm_object_lock(src_object);
-	/*
-	 * Copy object may have changed while we were unlocked
-	 */
-	old_copy = src_object->copy;
-	if (old_copy != NULL) {
-		/*
-		 * Try to get the locks (out of order)
-		 */
-		if (!vm_object_lock_try(old_copy)) {
-			vm_object_unlock(src_object);
-			tsleep((caddr_t) old_copy, PVM, "cpylck", 1);
-			goto Retry2;
-		}
-		/*
-		 * Consistency check
-		 */
-		if (old_copy->shadow != src_object ||
-		    old_copy->shadow_offset != (vm_offset_t) 0)
-			panic("vm_object_copy: copy/shadow inconsistency");
-
-		/*
-		 * Make the old copy-object shadow the new one. It will
-		 * receive no more pages from the original object.
-		 */
-
-		src_object->ref_count--;	/* remove ref. from old_copy */
-		if (old_copy->shadow)
-			TAILQ_REMOVE(&old_copy->shadow->reverse_shadow_head, old_copy, reverse_shadow_list);
-		old_copy->shadow = new_copy;
-		TAILQ_INSERT_TAIL(&old_copy->shadow->reverse_shadow_head, old_copy, reverse_shadow_list);
-		new_copy->ref_count++;	/* locking not needed - we have the
-					 * only pointer */
-		vm_object_unlock(old_copy);	/* done with old_copy */
-	}
-	new_start = (vm_offset_t) 0;	/* always shadow original at 0 */
-	new_end = (vm_offset_t) new_copy->size;	/* for the whole object */
 
 	/*
-	 * Point the new copy at the existing object.
+	 * Make another reference to the object
 	 */
-
-	new_copy->shadow = src_object;
-	TAILQ_INSERT_TAIL(&new_copy->shadow->reverse_shadow_head, new_copy, reverse_shadow_list);
-	new_copy->shadow_offset = new_start;
 	src_object->ref_count++;
-	src_object->copy = new_copy;
 
 	/*
-	 * Mark all the affected pages of the existing object copy-on-write.
+	 * Mark all of the pages copy-on-write.
 	 */
-	for (p = src_object->memq.tqh_first; p != NULL; p = p->listq.tqe_next)
-		if ((new_start <= p->offset) && (p->offset < new_end))
+	for (p = src_object->memq.tqh_first; p; p = p->listq.tqe_next)
+		if (src_offset <= p->offset &&
+		    p->offset < src_offset + size)
 			p->flags |= PG_COPYONWRITE;
 
-	vm_object_unlock(src_object);
+	*dst_object = src_object;
+	*dst_offset = src_offset;
 
-	*dst_object = new_copy;
-	*dst_offset = src_offset - new_start;
-	*src_needs_copy = FALSE;
+	/*
+	 * Must make a shadow when write is desired
+	 */
+	*src_needs_copy = TRUE;
+	return;
 }
 
 /*
@@ -979,7 +750,7 @@ vm_object_shadow(object, offset, length)
 	 * Allocate a new object with the given length
 	 */
 
-	if ((result = vm_object_allocate(length)) == NULL)
+	if ((result = vm_object_allocate(OBJT_DEFAULT, length)) == NULL)
 		panic("vm_object_shadow: no object for shadowing");
 
 	/*
@@ -988,16 +759,16 @@ vm_object_shadow(object, offset, length)
 	 * removing a reference to the source object.  Net result: no change
 	 * of reference count.
 	 */
-	result->shadow = source;
+	result->backing_object = source;
 	if (source)
-		TAILQ_INSERT_TAIL(&result->shadow->reverse_shadow_head, result, reverse_shadow_list);
+		TAILQ_INSERT_TAIL(&result->backing_object->shadow_head, result, shadow_list);
 
 	/*
 	 * Store the offset into the source object, and fix up the offset into
 	 * the new object.
 	 */
 
-	result->shadow_offset = *offset;
+	result->backing_object_offset = *offset;
 
 	/*
 	 * Return the new things
@@ -1009,103 +780,6 @@ vm_object_shadow(object, offset, length)
 
 
 /*
- *	vm_object_lookup looks in the object cache for an object with the
- *	specified pager and paging id.
- */
-
-vm_object_t
-vm_object_lookup(pager)
-	vm_pager_t pager;
-{
-	register vm_object_hash_entry_t entry;
-	vm_object_t object;
-
-	vm_object_cache_lock();
-
-	for (entry = vm_object_hashtable[OBJECT_HASH(pager)].lh_first;
-	    entry != NULL; entry = entry->hash_links.le_next) {
-		object = entry->object;
-		if (object->pager == pager) {
-			vm_object_lock(object);
-			if (object->ref_count == 0) {
-				TAILQ_REMOVE(&vm_object_cached_list, object,
-				    cached_list);
-				vm_object_cached--;
-			}
-			object->ref_count++;
-			vm_object_unlock(object);
-			vm_object_cache_unlock();
-			return (object);
-		}
-	}
-
-	vm_object_cache_unlock();
-	return (NULL);
-}
-
-/*
- *	vm_object_enter enters the specified object/pager/id into
- *	the hash table.
- */
-
-void
-vm_object_enter(object, pager)
-	vm_object_t object;
-	vm_pager_t pager;
-{
-	struct vm_object_hash_head *bucket;
-	register vm_object_hash_entry_t entry;
-
-	/*
-	 * We don't cache null objects, and we can't cache objects with the
-	 * null pager.
-	 */
-
-	if (object == NULL)
-		return;
-	if (pager == NULL)
-		return;
-
-	bucket = &vm_object_hashtable[OBJECT_HASH(pager)];
-	entry = (vm_object_hash_entry_t)
-	    malloc((u_long) sizeof *entry, M_VMOBJHASH, M_WAITOK);
-	entry->object = object;
-
-	vm_object_cache_lock();
-	LIST_INSERT_HEAD(bucket, entry, hash_links);
-	vm_object_cache_unlock();
-}
-
-/*
- *	vm_object_remove:
- *
- *	Remove the pager from the hash table.
- *	Note:  This assumes that the object cache
- *	is locked.  XXX this should be fixed
- *	by reorganizing vm_object_deallocate.
- */
-void
-vm_object_remove(pager)
-	register vm_pager_t pager;
-{
-	struct vm_object_hash_head *bucket;
-	register vm_object_hash_entry_t entry;
-	register vm_object_t object;
-
-	bucket = &vm_object_hashtable[OBJECT_HASH(pager)];
-
-	for (entry = bucket->lh_first;
-	    entry != NULL; entry = entry->hash_links.le_next) {
-		object = entry->object;
-		if (object->pager == pager) {
-			LIST_REMOVE(entry, hash_links);
-			free((caddr_t) entry, M_VMOBJHASH);
-			break;
-		}
-	}
-}
-
-/*
  * this version of collapse allows the operation to occur earlier and
  * when paging_in_progress is true for an object...  This is not a complete
  * operation, but should plug 99.9% of the rest of the leaks.
@@ -1119,16 +793,13 @@ vm_object_qcollapse(object)
 	register vm_page_t p, pp;
 	register vm_size_t size;
 
-	backing_object = object->shadow;
-	if (backing_object->shadow != NULL &&
-	    backing_object->shadow->copy == backing_object)
-		return;
+	backing_object = object->backing_object;
 	if (backing_object->ref_count != 1)
 		return;
 
 	backing_object->ref_count += 2;
 
-	backing_offset = object->shadow_offset;
+	backing_offset = object->backing_object_offset;
 	size = object->size;
 	p = backing_object->memq.tqh_first;
 	while (p) {
@@ -1144,25 +815,21 @@ vm_object_qcollapse(object)
 		new_offset = (p->offset - backing_offset);
 		if (p->offset < backing_offset ||
 		    new_offset >= size) {
-			if (backing_object->pager)
-				swap_pager_freespace(backing_object->pager,
+			if (backing_object->type == OBJT_SWAP)
+				swap_pager_freespace(backing_object,
 				    backing_object->paging_offset + p->offset, PAGE_SIZE);
-			vm_page_lock_queues();
 			vm_page_free(p);
-			vm_page_unlock_queues();
 		} else {
 			pp = vm_page_lookup(object, new_offset);
-			if (pp != NULL || (object->pager && vm_pager_has_page(object->pager,
-				    object->paging_offset + new_offset))) {
-				if (backing_object->pager)
-					swap_pager_freespace(backing_object->pager,
+			if (pp != NULL || (object->type == OBJT_SWAP && vm_pager_has_page(object,
+				    object->paging_offset + new_offset, NULL, NULL))) {
+				if (backing_object->type == OBJT_SWAP)
+					swap_pager_freespace(backing_object,
 					    backing_object->paging_offset + p->offset, PAGE_SIZE);
-				vm_page_lock_queues();
 				vm_page_free(p);
-				vm_page_unlock_queues();
 			} else {
-				if( backing_object->pager)
-					swap_pager_freespace(backing_object->pager,
+				if (backing_object->type == OBJT_SWAP)
+					swap_pager_freespace(backing_object,
 					    backing_object->paging_offset + p->offset, PAGE_SIZE);
 				vm_page_rename(p, object, new_offset);
 				p->dirty = VM_PAGE_BITS_ALL;
@@ -1173,35 +840,23 @@ vm_object_qcollapse(object)
 	backing_object->ref_count -= 2;
 }
 
-boolean_t vm_object_collapse_allowed = TRUE;
-
 /*
  *	vm_object_collapse:
  *
  *	Collapse an object with the object backing it.
  *	Pages in the backing object are moved into the
  *	parent, and the backing object is deallocated.
- *
- *	Requires that the object be locked and the page
- *	queues be unlocked.
- *
- *	This routine has significant changes by John S. Dyson
- *	to fix some swap memory leaks.  18 Dec 93
- *
  */
 void
 vm_object_collapse(object)
-	register vm_object_t object;
+	vm_object_t object;
 
 {
-	register vm_object_t backing_object;
-	register vm_offset_t backing_offset;
-	register vm_size_t size;
-	register vm_offset_t new_offset;
-	register vm_page_t p, pp;
-
-	if (!vm_object_collapse_allowed)
-		return;
+	vm_object_t backing_object;
+	vm_offset_t backing_offset;
+	vm_size_t size;
+	vm_offset_t new_offset;
+	vm_page_t p, pp;
 
 	while (TRUE) {
 		/*
@@ -1216,42 +871,27 @@ vm_object_collapse(object)
 		/*
 		 * Make sure there is a backing object.
 		 */
-		if ((backing_object = object->shadow) == NULL)
+		if ((backing_object = object->backing_object) == NULL)
 			return;
 
 		/*
 		 * we check the backing object first, because it is most likely
-		 * !OBJ_INTERNAL.
+		 * not collapsable.
 		 */
-		if ((backing_object->flags & OBJ_INTERNAL) == 0 ||
+		if (backing_object->handle != NULL ||
+		    (backing_object->type != OBJT_DEFAULT &&
+		     backing_object->type != OBJT_SWAP) ||
 		    (backing_object->flags & OBJ_DEAD) ||
-		    (object->flags & OBJ_INTERNAL) == 0 ||
-		    (object->flags & OBJ_DEAD))
+		    object->handle != NULL ||
+		    (object->type != OBJT_DEFAULT &&
+		     object->type != OBJT_SWAP) ||
+		    (object->flags & OBJ_DEAD)) {
 			return;
+		}
 
 		if (object->paging_in_progress != 0 ||
 		    backing_object->paging_in_progress != 0) {
-			if (vm_object_lock_try(backing_object)) {
-				vm_object_qcollapse(object);
-				vm_object_unlock(backing_object);
-			}
-			return;
-		}
-
-		vm_object_lock(backing_object);
-
-		/*
-		 * The backing object can't be a copy-object: the
-		 * shadow_offset for the copy-object must stay as 0.
-		 * Furthermore (for the 'we have all the pages' case), if we
-		 * bypass backing_object and just shadow the next object in
-		 * the chain, old pages from that object would then have to be
-		 * copied BOTH into the (former) backing_object and into the
-		 * parent object.
-		 */
-		if (backing_object->shadow != NULL &&
-		    backing_object->shadow->copy == backing_object) {
-			vm_object_unlock(backing_object);
+			vm_object_qcollapse(object);
 			return;
 		}
 
@@ -1261,7 +901,7 @@ vm_object_collapse(object)
 		 * the parent's reference to it.
 		 */
 
-		backing_offset = object->shadow_offset;
+		backing_offset = object->backing_object_offset;
 		size = object->size;
 
 		/*
@@ -1295,20 +935,16 @@ vm_object_collapse(object)
 
 				if (p->offset < backing_offset ||
 				    new_offset >= size) {
-					vm_page_lock_queues();
 					vm_page_protect(p, VM_PROT_NONE);
 					PAGE_WAKEUP(p);
 					vm_page_free(p);
-					vm_page_unlock_queues();
 				} else {
 					pp = vm_page_lookup(object, new_offset);
-					if (pp != NULL || (object->pager && vm_pager_has_page(object->pager,
-					    object->paging_offset + new_offset))) {
-						vm_page_lock_queues();
+					if (pp != NULL || (object->type == OBJT_SWAP && vm_pager_has_page(object,
+					    object->paging_offset + new_offset, NULL, NULL))) {
 						vm_page_protect(p, VM_PROT_NONE);
 						PAGE_WAKEUP(p);
 						vm_page_free(p);
-						vm_page_unlock_queues();
 					} else {
 						vm_page_rename(p, object, new_offset);
 					}
@@ -1319,36 +955,45 @@ vm_object_collapse(object)
 			 * Move the pager from backing_object to object.
 			 */
 
-			if (backing_object->pager) {
+			if (backing_object->type == OBJT_SWAP) {
 				backing_object->paging_in_progress++;
-				if (object->pager) {
-					vm_pager_t bopager;
-
+				if (object->type == OBJT_SWAP) {
 					object->paging_in_progress++;
 					/*
 					 * copy shadow object pages into ours
 					 * and destroy unneeded pages in
 					 * shadow object.
 					 */
-					bopager = backing_object->pager;
-					backing_object->pager = NULL;
 					swap_pager_copy(
-					    bopager, backing_object->paging_offset,
-					    object->pager, object->paging_offset,
-					    object->shadow_offset);
+					    backing_object, backing_object->paging_offset,
+					    object, object->paging_offset,
+					    object->backing_object_offset);
 					vm_object_pip_wakeup(object);
 				} else {
+					extern struct pagerlst swap_pager_un_object_list;
+
 					object->paging_in_progress++;
 					/*
-					 * grab the shadow objects pager
+					 * move the shadow backing_object's pager data to
+					 * "object" and convert "object" type to OBJT_SWAP.
 					 */
-					object->pager = backing_object->pager;
+					object->type = OBJT_SWAP;
+					object->pg_data = backing_object->pg_data;
 					object->paging_offset = backing_object->paging_offset + backing_offset;
-					backing_object->pager = NULL;
+					TAILQ_INSERT_TAIL(&swap_pager_un_object_list, object, pager_object_list);
+
+					/*
+					 * Convert backing object from OBJT_SWAP to
+					 * OBJT_DEFAULT. XXX - only the TAILQ_REMOVE is
+					 * actually necessary.
+					 */
+					backing_object->type = OBJT_DEFAULT;
+					backing_object->pg_data = NULL;
+					TAILQ_REMOVE(&swap_pager_un_object_list, backing_object, pager_object_list);
 					/*
 					 * free unnecessary blocks
 					 */
-					swap_pager_freespace(object->pager, 0, object->paging_offset);
+					swap_pager_freespace(object, 0, object->paging_offset);
 					vm_object_pip_wakeup(object);
 				}
 
@@ -1356,21 +1001,21 @@ vm_object_collapse(object)
 			}
 			/*
 			 * Object now shadows whatever backing_object did.
-			 * Note that the reference to backing_object->shadow
+			 * Note that the reference to backing_object->backing_object
 			 * moves from within backing_object to within object.
 			 */
 
-			TAILQ_REMOVE(&object->shadow->reverse_shadow_head, object,
-			    reverse_shadow_list);
-			if (backing_object->shadow)
-				TAILQ_REMOVE(&backing_object->shadow->reverse_shadow_head,
-				    backing_object, reverse_shadow_list);
-			object->shadow = backing_object->shadow;
-			if (object->shadow)
-				TAILQ_INSERT_TAIL(&object->shadow->reverse_shadow_head,
-				    object, reverse_shadow_list);
-
-			object->shadow_offset += backing_object->shadow_offset;
+			TAILQ_REMOVE(&object->backing_object->shadow_head, object,
+			    shadow_list);
+			if (backing_object->backing_object)
+				TAILQ_REMOVE(&backing_object->backing_object->shadow_head,
+				    backing_object, shadow_list);
+			object->backing_object = backing_object->backing_object;
+			if (object->backing_object)
+				TAILQ_INSERT_TAIL(&object->backing_object->shadow_head,
+				    object, shadow_list);
+
+			object->backing_object_offset += backing_object->backing_object_offset;
 			/*
 			 * Discard backing_object.
 			 *
@@ -1379,13 +1024,9 @@ vm_object_collapse(object)
 			 * necessary is to dispose of it.
 			 */
 
-			vm_object_unlock(backing_object);
-
-			simple_lock(&vm_object_list_lock);
 			TAILQ_REMOVE(&vm_object_list, backing_object,
 			    object_list);
 			vm_object_count--;
-			simple_unlock(&vm_object_list_lock);
 
 			free((caddr_t) backing_object, M_VMOBJ);
 
@@ -1401,8 +1042,7 @@ vm_object_collapse(object)
 			 * to check all of the paged-out pages, as well.
 			 */
 
-			if (backing_object->pager != NULL) {
-				vm_object_unlock(backing_object);
+			if (backing_object->type != OBJT_DEFAULT) {
 				return;
 			}
 			/*
@@ -1421,17 +1061,19 @@ vm_object_collapse(object)
 				 * the chain.
 				 */
 
-				if (p->offset >= backing_offset &&
-				    new_offset <= size &&
-				    ((pp = vm_page_lookup(object, new_offset)) == NULL ||
-					!pp->valid) &&
-				    (!object->pager || !vm_pager_has_page(object->pager, object->paging_offset + new_offset))) {
-					/*
-					 * Page still needed. Can't go any
-					 * further.
-					 */
-					vm_object_unlock(backing_object);
-					return;
+				if (p->offset >= backing_offset && new_offset <= size) {
+
+					pp = vm_page_lookup(object, new_offset);
+
+					if ((pp == NULL || pp->valid == 0) &&
+				   	    !vm_pager_has_page(object, object->paging_offset + new_offset, NULL, NULL)) {
+
+						/*
+						 * Page still needed. Can't go any
+						 * further.
+						 */
+						return;
+					}
 				}
 			}
 
@@ -1441,22 +1083,15 @@ vm_object_collapse(object)
 			 * it, since its reference count is at least 2.
 			 */
 
-			TAILQ_REMOVE(&object->shadow->reverse_shadow_head,
-			    object, reverse_shadow_list);
-			vm_object_reference(object->shadow = backing_object->shadow);
-			if (object->shadow)
-				TAILQ_INSERT_TAIL(&object->shadow->reverse_shadow_head,
-				    object, reverse_shadow_list);
-			object->shadow_offset += backing_object->shadow_offset;
+			TAILQ_REMOVE(&object->backing_object->shadow_head,
+			    object, shadow_list);
+			vm_object_reference(object->backing_object = backing_object->backing_object);
+			if (object->backing_object)
+				TAILQ_INSERT_TAIL(&object->backing_object->shadow_head,
+				    object, shadow_list);
+			object->backing_object_offset += backing_object->backing_object_offset;
 
 			/*
-			 * Backing object might have had a copy pointer to us.
-			 * If it did, clear it.
-			 */
-			if (backing_object->copy == object) {
-				backing_object->copy = NULL;
-			}
-			/*
 			 * Drop the reference count on backing_object. Since
 			 * its ref_count was at least 2, it will not vanish;
 			 * so we don't need to call vm_object_deallocate.
@@ -1464,7 +1099,6 @@ vm_object_collapse(object)
 			if (backing_object->ref_count == 1)
 				printf("should have called obj deallocate\n");
 			backing_object->ref_count--;
-			vm_object_unlock(backing_object);
 
 			object_bypasses++;
 
@@ -1514,7 +1148,7 @@ again:
 				}
 				if ((p->flags & PG_BUSY) || p->busy) {
 					p->flags |= PG_WANTED;
-					tsleep((caddr_t) p, PVM, "vmopar", 0);
+					tsleep(p, PVM, "vmopar", 0);
 					splx(s);
 					goto again;
 				}
@@ -1525,10 +1159,8 @@ again:
 						continue;
 				}
 				vm_page_protect(p, VM_PROT_NONE);
-				vm_page_lock_queues();
 				PAGE_WAKEUP(p);
 				vm_page_free(p);
-				vm_page_unlock_queues();
 			}
 		}
 	} else {
@@ -1541,7 +1173,7 @@ again:
 				}
 				if ((p->flags & PG_BUSY) || p->busy) {
 					p->flags |= PG_WANTED;
-					tsleep((caddr_t) p, PVM, "vmopar", 0);
+					tsleep(p, PVM, "vmopar", 0);
 					splx(s);
 					goto again;
 				}
@@ -1552,10 +1184,8 @@ again:
 						continue;
 				}
 				vm_page_protect(p, VM_PROT_NONE);
-				vm_page_lock_queues();
 				PAGE_WAKEUP(p);
 				vm_page_free(p);
-				vm_page_unlock_queues();
 			}
 			start += PAGE_SIZE;
 			size -= PAGE_SIZE;
@@ -1603,7 +1233,6 @@ vm_object_coalesce(prev_object, next_object,
 	if (prev_object == NULL) {
 		return (TRUE);
 	}
-	vm_object_lock(prev_object);
 
 	/*
 	 * Try to collapse the object first
@@ -1617,10 +1246,8 @@ vm_object_coalesce(prev_object, next_object,
 	 */
 
 	if (prev_object->ref_count > 1 ||
-	    prev_object->pager != NULL ||
-	    prev_object->shadow != NULL ||
-	    prev_object->copy != NULL) {
-		vm_object_unlock(prev_object);
+	    prev_object->type != OBJT_DEFAULT ||
+	    prev_object->backing_object != NULL) {
 		return (FALSE);
 	}
 	/*
@@ -1639,7 +1266,6 @@ vm_object_coalesce(prev_object, next_object,
 	if (newsize > prev_object->size)
 		prev_object->size = newsize;
 
-	vm_object_unlock(prev_object);
 	return (TRUE);
 }
 
@@ -1655,10 +1281,10 @@ vm_object_page_lookup(object, offset)
 	vm_page_t m;
 
 	if (!(m = vm_page_lookup(object, offset))) {
-		if (!object->shadow)
+		if (!object->backing_object)
 			return 0;
 		else
-			return vm_object_page_lookup(object->shadow, offset + object->shadow_offset);
+			return vm_object_page_lookup(object->backing_object, offset + object->backing_object_offset);
 	}
 	return m;
 }
@@ -1699,7 +1325,7 @@ _vm_object_in_map(map, object, entry)
 			tmpe = tmpe->next;
 		}
 	} else if (obj = entry->object.vm_object) {
-		for(; obj; obj=obj->shadow)
+		for(; obj; obj=obj->backing_object)
 			if( obj == object) {
 				return 1;
 			}
@@ -1748,25 +1374,6 @@ vm_object_check() {
 	int i;
 	int maxhash = 0;
 	vm_object_t object;
-	vm_object_hash_entry_t entry;
-
-	/*
-	 * make sure that no internal objs are hashed
-	 */
-	for (i=0; i<VM_OBJECT_HASH_COUNT;i++) {
-		int lsize = 0;
-		for (entry = vm_object_hashtable[i].lh_first;
-		    entry != NULL; entry = entry->hash_links.le_next) {
-			if( entry->object->flags & OBJ_INTERNAL) {
-				printf("vmochk: internal obj on hash: size: %d\n", entry->object->size);
-			}
-			++lsize;
-		}
-		if( lsize > maxhash)
-			maxhash = lsize;
-	}
-
-	printf("maximum object hash queue size: %d\n",  maxhash);
 
 	/*
 	 * make sure that internal objs are in a map somewhere
@@ -1775,14 +1382,15 @@ vm_object_check() {
 	for (object = vm_object_list.tqh_first;
 			object != NULL;
 			object = object->object_list.tqe_next) {
-		if (object->flags & OBJ_INTERNAL) {
+		if (object->handle == NULL &&
+		    (object->type == OBJT_DEFAULT || object->type == OBJT_SWAP)) {
 			if (object->ref_count == 0) {
 				printf("vmochk: internal obj has zero ref count: %d\n",
 					object->size);
 			}
 			if (!vm_object_in_map(object)) {
-				printf("vmochk: internal obj is not in a map: ref: %d, size: %d, pager: 0x%x, shadow: 0x%x\n",
-				    object->ref_count, object->size, object->pager, object->shadow);
+				printf("vmochk: internal obj is not in a map: ref: %d, size: %d, pg_data: 0x%x, backing_object: 0x%x\n",
+				    object->ref_count, object->size, object->pg_data, object->backing_object);
 			}
 		}
 	}
@@ -1806,9 +1414,9 @@ vm_object_print(object, full)
 	iprintf("Object 0x%x: size=0x%x, res=%d, ref=%d, ",
 	    (int) object, (int) object->size,
 	    object->resident_page_count, object->ref_count);
-	printf("pager=0x%x+0x%x, shadow=(0x%x)+0x%x\n",
-	    (int) object->pager, (int) object->paging_offset,
-	    (int) object->shadow, (int) object->shadow_offset);
+	printf("pg_data=0x%x+0x%x, backing_object=(0x%x)+0x%x\n",
+	    (int) object->pg_data, (int) object->paging_offset,
+	    (int) object->backing_object, (int) object->backing_object_offset);
 	printf("cache: next=%p, prev=%p\n",
 	    object->cached_list.tqe_next, object->cached_list.tqe_prev);