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, 36 insertions, 254 deletions

diff --git a/sys/vm/vm_fault.c b/sys/vm/vm_fault.c
index c061c3e..debb3c9 100644
--- a/sys/vm/vm_fault.c
+++ b/sys/vm/vm_fault.c
@@ -66,7 +66,7 @@
  * any improvements or extensions that they make and grant Carnegie the
  * rights to redistribute these changes.
  *
- * $Id: vm_fault.c,v 1.24 1995/05/18 02:59:22 davidg Exp $
+ * $Id: vm_fault.c,v 1.25 1995/05/30 08:15:59 rgrimes Exp $
  */
 
 /*
@@ -76,6 +76,7 @@
 #include <sys/param.h>
 #include <sys/systm.h>
 #include <sys/proc.h>
+#include <sys/vnode.h>
 #include <sys/resource.h>
 #include <sys/signalvar.h>
 #include <sys/resourcevar.h>
@@ -84,19 +85,16 @@
 #include <vm/vm_page.h>
 #include <vm/vm_pageout.h>
 #include <vm/vm_kern.h>
+#include <vm/vm_pager.h>
+#include <vm/vnode_pager.h>
 
 int vm_fault_additional_pages __P((vm_object_t, vm_offset_t, vm_page_t, int, int, vm_page_t *, int *));
 
 #define VM_FAULT_READ_AHEAD 4
-#define VM_FAULT_READ_AHEAD_MIN 1
 #define VM_FAULT_READ_BEHIND 3
 #define VM_FAULT_READ (VM_FAULT_READ_AHEAD+VM_FAULT_READ_BEHIND+1)
 extern int swap_pager_full;
 
-struct vnode *vnode_pager_lock __P((vm_object_t object));
-void vnode_pager_unlock __P((struct vnode *));
-
-
 /*
  *	vm_fault:
  *
@@ -148,16 +146,12 @@ vm_fault(map, vaddr, fault_type, change_wiring)
  */
 #define	FREE_PAGE(m)	{				\
 	PAGE_WAKEUP(m);					\
-	vm_page_lock_queues();				\
 	vm_page_free(m);				\
-	vm_page_unlock_queues();			\
 }
 
 #define	RELEASE_PAGE(m)	{				\
 	PAGE_WAKEUP(m);					\
-	vm_page_lock_queues();				\
 	if ((m->flags & PG_ACTIVE) == 0) vm_page_activate(m);		\
-	vm_page_unlock_queues();			\
 }
 
 #define	UNLOCK_MAP	{				\
@@ -169,15 +163,12 @@ vm_fault(map, vaddr, fault_type, change_wiring)
 
 #define	UNLOCK_THINGS	{				\
 	vm_object_pip_wakeup(object); \
-	vm_object_unlock(object);			\
 	if (object != first_object) {			\
-		vm_object_lock(first_object);		\
 		FREE_PAGE(first_m);			\
 		vm_object_pip_wakeup(first_object); \
-		vm_object_unlock(first_object);		\
 	}						\
 	UNLOCK_MAP;					\
-	if (vp != NULL) vnode_pager_unlock(vp);		\
+	if (vp != NULL) VOP_UNLOCK(vp);			\
 }
 
 #define	UNLOCK_AND_DEALLOCATE	{			\
@@ -198,7 +189,7 @@ RetryFault:;
 		return (result);
 	}
 
-	vp = (struct vnode *) vnode_pager_lock(first_object);
+	vp = vnode_pager_lock(first_object);
 
 	lookup_still_valid = TRUE;
 
@@ -214,8 +205,6 @@ RetryFault:;
 	 * they will stay around as well.
 	 */
 
-	vm_object_lock(first_object);
-
 	first_object->ref_count++;
 	first_object->paging_in_progress++;
 
@@ -223,7 +212,7 @@ RetryFault:;
 	 * INVARIANTS (through entire routine):
 	 *
 	 * 1)	At all times, we must either have the object lock or a busy
-	 * page in some object to prevent some other thread from trying to
+	 * page in some object to prevent some other process from trying to
 	 * bring in the same page.
 	 *
 	 * Note that we cannot hold any locks during the pager access or when
@@ -237,7 +226,7 @@ RetryFault:;
 	 * 2)	Once we have a busy page, we must remove it from the pageout
 	 * queues, so that the pageout daemon will not grab it away.
 	 *
-	 * 3)	To prevent another thread from racing us down the shadow chain
+	 * 3)	To prevent another process from racing us down the shadow chain
 	 * and entering a new page in the top object before we do, we must
 	 * keep a busy page in the top object while following the shadow
 	 * chain.
@@ -273,7 +262,7 @@ RetryFault:;
 				if ((m->flags & PG_BUSY) || m->busy) {
 					m->flags |= PG_WANTED | PG_REFERENCED;
 					cnt.v_intrans++;
-					tsleep((caddr_t) m, PSWP, "vmpfw", 0);
+					tsleep(m, PSWP, "vmpfw", 0);
 				}
 				splx(s);
 				vm_object_deallocate(first_object);
@@ -288,7 +277,7 @@ RetryFault:;
 			}
 
 			/*
-			 * Mark page busy for other threads, and the pagedaemon.
+			 * Mark page busy for other processes, and the pagedaemon.
 			 */
 			m->flags |= PG_BUSY;
 			if (m->valid && ((m->valid & VM_PAGE_BITS_ALL) != VM_PAGE_BITS_ALL) &&
@@ -297,16 +286,18 @@ RetryFault:;
 			}
 			break;
 		}
-		if (((object->pager != NULL) && (!change_wiring || wired))
+		if (((object->type != OBJT_DEFAULT) && (!change_wiring || wired))
 		    || (object == first_object)) {
 
 			if (offset >= object->size) {
 				UNLOCK_AND_DEALLOCATE;
 				return (KERN_PROTECTION_FAILURE);
 			}
-			if (swap_pager_full && !object->shadow && (!object->pager ||
-				(object->pager && object->pager->pg_type == PG_SWAP &&
-				    !vm_pager_has_page(object->pager, offset + object->paging_offset)))) {
+#if 0	/* XXX is this really necessary? */
+			if (swap_pager_full && !object->backing_object &&
+			    (object->type == OBJT_DEFAULT ||
+			    (object->type == OBJT_SWAP && 
+			     !vm_pager_has_page(object, offset + object->paging_offset, NULL, NULL)))) {
 				if (vaddr < VM_MAXUSER_ADDRESS && curproc && curproc->p_pid >= 48) {	/* XXX */
 					printf("Process %lu killed by vm_fault -- out of swap\n", (u_long) curproc->p_pid);
 					psignal(curproc, SIGKILL);
@@ -315,6 +306,7 @@ RetryFault:;
 					resetpriority(curproc);
 				}
 			}
+#endif
 			/*
 			 * Allocate a new page for this object/offset pair.
 			 */
@@ -328,17 +320,12 @@ RetryFault:;
 			}
 		}
 readrest:
-		if (object->pager != NULL && (!change_wiring || wired)) {
+		if (object->type != OBJT_DEFAULT && (!change_wiring || wired)) {
 			int rv;
 			int faultcount;
 			int reqpage;
 
 			/*
-			 * Now that we have a busy page, we can release the
-			 * object lock.
-			 */
-			vm_object_unlock(object);
-			/*
 			 * now we find out if any other pages should be paged
 			 * in at this time this routine checks to see if the
 			 * pages surrounding this fault reside in the same
@@ -362,14 +349,13 @@ readrest:
 			UNLOCK_MAP;
 
 			rv = faultcount ?
-			    vm_pager_get_pages(object->pager,
-			    marray, faultcount, reqpage, TRUE) : VM_PAGER_FAIL;
+			    vm_pager_get_pages(object, marray, faultcount,
+				reqpage) : VM_PAGER_FAIL;
 			if (rv == VM_PAGER_OK) {
 				/*
 				 * Found the page. Leave it busy while we play
 				 * with it.
 				 */
-				vm_object_lock(object);
 
 				/*
 				 * Relookup in case pager changed page. Pager
@@ -392,11 +378,11 @@ readrest:
 			 * object/offset); before doing so, we must get back
 			 * our object lock to preserve our invariant.
 			 *
-			 * Also wake up any other thread that may want to bring
+			 * Also wake up any other process that may want to bring
 			 * in this page.
 			 *
 			 * If this is the top-level object, we must leave the
-			 * busy page to prevent another thread from rushing
+			 * busy page to prevent another process from rushing
 			 * past us, and inserting the page in that object at
 			 * the same time that we are.
 			 */
@@ -404,7 +390,6 @@ readrest:
 			if (rv == VM_PAGER_ERROR)
 				printf("vm_fault: pager input (probably hardware) error, PID %d failure\n",
 				    curproc->p_pid);
-			vm_object_lock(object);
 			/*
 			 * Data outside the range of the pager or an I/O error
 			 */
@@ -427,7 +412,7 @@ readrest:
 			}
 		}
 		/*
-		 * We get here if the object has no pager (or unwiring) or the
+		 * We get here if the object has default pager (or unwiring) or the
 		 * pager doesn't have the page.
 		 */
 		if (object == first_object)
@@ -438,8 +423,8 @@ readrest:
 		 * unlocking the current one.
 		 */
 
-		offset += object->shadow_offset;
-		next_object = object->shadow;
+		offset += object->backing_object_offset;
+		next_object = object->backing_object;
 		if (next_object == NULL) {
 			/*
 			 * If there's no object left, fill the page in the top
@@ -447,12 +432,10 @@ readrest:
 			 */
 			if (object != first_object) {
 				vm_object_pip_wakeup(object);
-				vm_object_unlock(object);
 
 				object = first_object;
 				offset = first_offset;
 				m = first_m;
-				vm_object_lock(object);
 			}
 			first_m = NULL;
 
@@ -461,11 +444,9 @@ readrest:
 			cnt.v_zfod++;
 			break;
 		} else {
-			vm_object_lock(next_object);
 			if (object != first_object) {
 				vm_object_pip_wakeup(object);
 			}
-			vm_object_unlock(object);
 			object = next_object;
 			object->paging_in_progress++;
 		}
@@ -529,19 +510,15 @@ readrest:
 			 * call.
 			 */
 
-			vm_page_lock_queues();
-
 			if ((m->flags & PG_ACTIVE) == 0)
 				vm_page_activate(m);
 			vm_page_protect(m, VM_PROT_NONE);
-			vm_page_unlock_queues();
 
 			/*
 			 * We no longer need the old page or object.
 			 */
 			PAGE_WAKEUP(m);
 			vm_object_pip_wakeup(object);
-			vm_object_unlock(object);
 
 			/*
 			 * Only use the new page below...
@@ -555,9 +532,7 @@ readrest:
 			/*
 			 * Now that we've gotten the copy out of the way,
 			 * let's try to collapse the top object.
-			 */
-			vm_object_lock(object);
-			/*
+			 *
 			 * But we have to play ugly games with
 			 * paging_in_progress to do that...
 			 */
@@ -571,176 +546,6 @@ readrest:
 	}
 
 	/*
-	 * If the page is being written, but hasn't been copied to the
-	 * copy-object, we have to copy it there.
-	 */
-RetryCopy:
-	if (first_object->copy != NULL) {
-		vm_object_t copy_object = first_object->copy;
-		vm_offset_t copy_offset;
-		vm_page_t copy_m;
-
-		/*
-		 * We only need to copy if we want to write it.
-		 */
-		if ((fault_type & VM_PROT_WRITE) == 0) {
-			prot &= ~VM_PROT_WRITE;
-			m->flags |= PG_COPYONWRITE;
-		} else {
-			/*
-			 * Try to get the lock on the copy_object.
-			 */
-			if (!vm_object_lock_try(copy_object)) {
-				vm_object_unlock(object);
-				/* should spin a bit here... */
-				vm_object_lock(object);
-				goto RetryCopy;
-			}
-			/*
-			 * Make another reference to the copy-object, to keep
-			 * it from disappearing during the copy.
-			 */
-			copy_object->ref_count++;
-
-			/*
-			 * Does the page exist in the copy?
-			 */
-			copy_offset = first_offset
-			    - copy_object->shadow_offset;
-			copy_m = vm_page_lookup(copy_object, copy_offset);
-			page_exists = (copy_m != NULL);
-			if (page_exists) {
-				if ((copy_m->flags & PG_BUSY) || copy_m->busy) {
-					/*
-					 * If the page is being brought in,
-					 * wait for it and then retry.
-					 */
-					RELEASE_PAGE(m);
-					copy_object->ref_count--;
-					vm_object_unlock(copy_object);
-					UNLOCK_THINGS;
-					spl = splhigh();
-					if ((copy_m->flags & PG_BUSY) || copy_m->busy) {
-						copy_m->flags |= PG_WANTED | PG_REFERENCED;
-						tsleep((caddr_t) copy_m, PSWP, "vmpfwc", 0);
-					}
-					splx(spl);
-					vm_object_deallocate(first_object);
-					goto RetryFault;
-				}
-			}
-			/*
-			 * If the page is not in memory (in the object) and
-			 * the object has a pager, we have to check if the
-			 * pager has the data in secondary storage.
-			 */
-			if (!page_exists) {
-
-				/*
-				 * If we don't allocate a (blank) page here...
-				 * another thread could try to page it in,
-				 * allocate a page, and then block on the busy
-				 * page in its shadow (first_object).  Then
-				 * we'd trip over the busy page after we found
-				 * that the copy_object's pager doesn't have
-				 * the page...
-				 */
-				copy_m = vm_page_alloc(copy_object, copy_offset, VM_ALLOC_NORMAL);
-				if (copy_m == NULL) {
-					/*
-					 * Wait for a page, then retry.
-					 */
-					RELEASE_PAGE(m);
-					copy_object->ref_count--;
-					vm_object_unlock(copy_object);
-					UNLOCK_AND_DEALLOCATE;
-					VM_WAIT;
-					goto RetryFault;
-				}
-				if (copy_object->pager != NULL) {
-					vm_object_unlock(object);
-					vm_object_unlock(copy_object);
-					UNLOCK_MAP;
-
-					page_exists = vm_pager_has_page(
-					    copy_object->pager,
-					    (copy_offset + copy_object->paging_offset));
-
-					vm_object_lock(copy_object);
-
-					/*
-					 * Since the map is unlocked, someone
-					 * else could have copied this object
-					 * and put a different copy_object
-					 * between the two.  Or, the last
-					 * reference to the copy-object (other
-					 * than the one we have) may have
-					 * disappeared - if that has happened,
-					 * we don't need to make the copy.
-					 */
-					if (copy_object->shadow != object ||
-					    copy_object->ref_count == 1) {
-						/*
-						 * Gaah... start over!
-						 */
-						FREE_PAGE(copy_m);
-						vm_object_unlock(copy_object);
-						vm_object_deallocate(copy_object);
-						/* may block */
-						vm_object_lock(object);
-						goto RetryCopy;
-					}
-					vm_object_lock(object);
-
-					if (page_exists) {
-						/*
-						 * We didn't need the page
-						 */
-						FREE_PAGE(copy_m);
-					}
-				}
-			}
-			if (!page_exists) {
-				/*
-				 * Must copy page into copy-object.
-				 */
-				vm_page_copy(m, copy_m);
-				copy_m->valid = VM_PAGE_BITS_ALL;
-
-				/*
-				 * Things to remember: 1. The copied page must
-				 * be marked 'dirty' so it will be paged out
-				 * to the copy object. 2. If the old page was
-				 * in use by any users of the copy-object, it
-				 * must be removed from all pmaps.  (We can't
-				 * know which pmaps use it.)
-				 */
-				vm_page_lock_queues();
-
-				if ((old_m->flags & PG_ACTIVE) == 0)
-					vm_page_activate(old_m);
-
-				vm_page_protect(old_m, VM_PROT_NONE);
-				copy_m->dirty = VM_PAGE_BITS_ALL;
-				if ((copy_m->flags & PG_ACTIVE) == 0)
-					vm_page_activate(copy_m);
-				vm_page_unlock_queues();
-
-				PAGE_WAKEUP(copy_m);
-			}
-			/*
-			 * The reference count on copy_object must be at least
-			 * 2: one for our extra reference, and at least one
-			 * from the outside world (we checked that when we
-			 * last locked copy_object).
-			 */
-			copy_object->ref_count--;
-			vm_object_unlock(copy_object);
-			m->flags &= ~PG_COPYONWRITE;
-		}
-	}
-
-	/*
 	 * We must verify that the maps have not changed since our last
 	 * lookup.
 	 */
@@ -754,10 +559,9 @@ RetryCopy:
 		 * Since map entries may be pageable, make sure we can take a
 		 * page fault on them.
 		 */
-		vm_object_unlock(object);
 
 		/*
-		 * To avoid trying to write_lock the map while another thread
+		 * To avoid trying to write_lock the map while another process
 		 * has it read_locked (in vm_map_pageable), we do not try for
 		 * write permission.  If the page is still writable, we will
 		 * get write permission.  If it is not, or has been marked
@@ -767,8 +571,6 @@ RetryCopy:
 		result = vm_map_lookup(&map, vaddr, fault_type & ~VM_PROT_WRITE,
 		    &entry, &retry_object, &retry_offset, &retry_prot, &wired, &su);
 
-		vm_object_lock(object);
-
 		/*
 		 * If we don't need the page any longer, put it on the active
 		 * list (the easiest thing to do here).  If no one needs it,
@@ -815,8 +617,6 @@ RetryCopy:
 	 * once in each map for which it is wired.
 	 */
 
-	vm_object_unlock(object);
-
 	/*
 	 * Put this page into the physical map. We had to do the unlock above
 	 * because pmap_enter may cause other faults.   We don't put the page
@@ -849,8 +649,6 @@ RetryCopy:
 	 * If the page is not wired down, then put it where the pageout daemon
 	 * can find it.
 	 */
-	vm_object_lock(object);
-	vm_page_lock_queues();
 	if (change_wiring) {
 		if (wired)
 			vm_page_wire(m);
@@ -868,7 +666,6 @@ RetryCopy:
 			curproc->p_stats->p_ru.ru_minflt++;
 		}
 	}
-	vm_page_unlock_queues();
 
 	/*
 	 * Unlock everything, and return
@@ -948,8 +745,6 @@ vm_fault_unwire(map, start, end)
 	 * mappings from the physical map system.
 	 */
 
-	vm_page_lock_queues();
-
 	for (va = start; va < end; va += PAGE_SIZE) {
 		pa = pmap_extract(pmap, va);
 		if (pa == (vm_offset_t) 0) {
@@ -958,7 +753,6 @@ vm_fault_unwire(map, start, end)
 		pmap_change_wiring(pmap, va, FALSE);
 		vm_page_unwire(PHYS_TO_VM_PAGE(pa));
 	}
-	vm_page_unlock_queues();
 
 	/*
 	 * Inform the physical mapping system that the range of addresses may
@@ -1008,7 +802,7 @@ vm_fault_copy_entry(dst_map, src_map, dst_entry, src_entry)
 	 * Create the top-level object for the destination entry. (Doesn't
 	 * actually shadow anything - we copy the pages directly.)
 	 */
-	dst_object = vm_object_allocate(
+	dst_object = vm_object_allocate(OBJT_DEFAULT,
 	    (vm_size_t) (dst_entry->end - dst_entry->start));
 
 	dst_entry->object.vm_object = dst_object;
@@ -1028,13 +822,10 @@ vm_fault_copy_entry(dst_map, src_map, dst_entry, src_entry)
 		/*
 		 * Allocate a page in the destination object
 		 */
-		vm_object_lock(dst_object);
 		do {
 			dst_m = vm_page_alloc(dst_object, dst_offset, VM_ALLOC_NORMAL);
 			if (dst_m == NULL) {
-				vm_object_unlock(dst_object);
 				VM_WAIT;
-				vm_object_lock(dst_object);
 			}
 		} while (dst_m == NULL);
 
@@ -1043,7 +834,6 @@ vm_fault_copy_entry(dst_map, src_map, dst_entry, src_entry)
 		 * (Because the source is wired down, the page will be in
 		 * memory.)
 		 */
-		vm_object_lock(src_object);
 		src_m = vm_page_lookup(src_object, dst_offset + src_offset);
 		if (src_m == NULL)
 			panic("vm_fault_copy_wired: page missing");
@@ -1053,8 +843,6 @@ vm_fault_copy_entry(dst_map, src_map, dst_entry, src_entry)
 		/*
 		 * Enter it in the pmap...
 		 */
-		vm_object_unlock(src_object);
-		vm_object_unlock(dst_object);
 
 		dst_m->flags |= PG_WRITEABLE;
 		dst_m->flags |= PG_MAPPED;
@@ -1064,12 +852,8 @@ vm_fault_copy_entry(dst_map, src_map, dst_entry, src_entry)
 		/*
 		 * Mark it no longer busy, and put it on the active list.
 		 */
-		vm_object_lock(dst_object);
-		vm_page_lock_queues();
 		vm_page_activate(dst_m);
-		vm_page_unlock_queues();
 		PAGE_WAKEUP(dst_m);
-		vm_object_unlock(dst_object);
 	}
 }
 
@@ -1093,18 +877,16 @@ vm_fault_page_lookup(object, offset, rtobject, rtoffset, rtm)
 	*rtoffset = 0;
 
 	while (!(m = vm_page_lookup(object, offset))) {
-		if (object->pager) {
-			if (vm_pager_has_page(object->pager, object->paging_offset + offset)) {
-				*rtobject = object;
-				*rtoffset = offset;
-				return 1;
-			}
+		if (vm_pager_has_page(object, object->paging_offset + offset, NULL, NULL)) {
+			*rtobject = object;
+			*rtoffset = offset;
+			return 1;
 		}
-		if (!object->shadow)
+		if (!object->backing_object)
 			return 0;
 		else {
-			offset += object->shadow_offset;
-			object = object->shadow;
+			offset += object->backing_object_offset;
+			object = object->backing_object;
 		}
 	}
 	*rtobject = object;
@@ -1155,7 +937,7 @@ vm_fault_additional_pages(first_object, first_offset, m, rbehind, raheada, marra
 	 * if the requested page is not available, then give up now
 	 */
 
-	if (!vm_pager_has_page(object->pager, object->paging_offset + offset))
+	if (!vm_pager_has_page(object, object->paging_offset + offset, NULL, NULL))
 		return 0;
 
 	/*