BSD 4.4 Lite Kernel Sources

34 files changed, 14336 insertions, 0 deletions

diff --git a/sys/vm/device_pager.c b/sys/vm/device_pager.c
new file mode 100644
index 0000000..235c917a
--- /dev/null
+++ b/sys/vm/device_pager.c
@@ -0,0 +1,368 @@
+/*
+ * Copyright (c) 1990 University of Utah.
+ * Copyright (c) 1991, 1993
+ *	The Regents of the University of California.  All rights reserved.
+ *
+ * This code is derived from software contributed to Berkeley by
+ * the Systems Programming Group of the University of Utah Computer
+ * Science Department.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. All advertising materials mentioning features or use of this software
+ *    must display the following acknowledgement:
+ *	This product includes software developed by the University of
+ *	California, Berkeley and its contributors.
+ * 4. Neither the name of the University nor the names of its contributors
+ *    may be used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ *
+ *	@(#)device_pager.c	8.5 (Berkeley) 1/12/94
+ */
+
+/*
+ * Page to/from special files.
+ */
+
+#include <sys/param.h>
+#include <sys/systm.h>
+#include <sys/conf.h>
+#include <sys/mman.h>
+#include <sys/malloc.h>
+
+#include <vm/vm.h>
+#include <vm/vm_kern.h>
+#include <vm/vm_page.h>
+#include <vm/device_pager.h>
+
+struct pagerlst	dev_pager_list;		/* list of managed devices */
+struct pglist	dev_pager_fakelist;	/* list of available vm_page_t's */
+
+#ifdef DEBUG
+int	dpagerdebug = 0;
+#define	DDB_FOLLOW	0x01
+#define DDB_INIT	0x02
+#define DDB_ALLOC	0x04
+#define DDB_FAIL	0x08
+#endif
+
+static vm_pager_t	 dev_pager_alloc
+			    __P((caddr_t, vm_size_t, vm_prot_t, vm_offset_t));
+static void		 dev_pager_dealloc __P((vm_pager_t));
+static int		 dev_pager_getpage
+			    __P((vm_pager_t, vm_page_t *, int, boolean_t));
+static boolean_t	 dev_pager_haspage __P((vm_pager_t, vm_offset_t));
+static void		 dev_pager_init __P((void));
+static int		 dev_pager_putpage
+			    __P((vm_pager_t, vm_page_t *, int, boolean_t));
+static vm_page_t	 dev_pager_getfake __P((vm_offset_t));
+static void		 dev_pager_putfake __P((vm_page_t));
+
+struct pagerops devicepagerops = {
+	dev_pager_init,
+	dev_pager_alloc,
+	dev_pager_dealloc,
+	dev_pager_getpage,
+	dev_pager_putpage,
+	dev_pager_haspage,
+	vm_pager_clusternull
+};
+
+static void
+dev_pager_init()
+{
+#ifdef DEBUG
+	if (dpagerdebug & DDB_FOLLOW)
+		printf("dev_pager_init()\n");
+#endif
+	TAILQ_INIT(&dev_pager_list);
+	TAILQ_INIT(&dev_pager_fakelist);
+}
+
+static vm_pager_t
+dev_pager_alloc(handle, size, prot, foff)
+	caddr_t handle;
+	vm_size_t size;
+	vm_prot_t prot;
+	vm_offset_t foff;
+{
+	dev_t dev;
+	vm_pager_t pager;
+	int (*mapfunc)();
+	vm_object_t object;
+	dev_pager_t devp;
+	int npages, off;
+
+#ifdef DEBUG
+	if (dpagerdebug & DDB_FOLLOW)
+		printf("dev_pager_alloc(%x, %x, %x, %x)\n",
+		       handle, size, prot, foff);
+#endif
+#ifdef DIAGNOSTIC
+	/*
+	 * Pageout to device, should never happen.
+	 */
+	if (handle == NULL)
+		panic("dev_pager_alloc called");
+#endif
+
+	/*
+	 * Make sure this device can be mapped.
+	 */
+	dev = (dev_t)handle;
+	mapfunc = cdevsw[major(dev)].d_mmap;
+	if (mapfunc == NULL || mapfunc == enodev || mapfunc == nullop)
+		return(NULL);
+
+	/*
+	 * Offset should be page aligned.
+	 */
+	if (foff & PAGE_MASK)
+		return(NULL);
+
+	/*
+	 * Check that the specified range of the device allows the
+	 * desired protection.
+	 *
+	 * XXX assumes VM_PROT_* == PROT_*
+	 */
+	npages = atop(round_page(size));
+	for (off = foff; npages--; off += PAGE_SIZE)
+		if ((*mapfunc)(dev, off, (int)prot) == -1)
+			return(NULL);
+
+	/*
+	 * Look up pager, creating as necessary.
+	 */
+top:
+	pager = vm_pager_lookup(&dev_pager_list, handle);
+	if (pager == NULL) {
+		/*
+		 * Allocate and initialize pager structs
+		 */
+		pager = (vm_pager_t)malloc(sizeof *pager, M_VMPAGER, M_WAITOK);
+		if (pager == NULL)
+			return(NULL);
+		devp = (dev_pager_t)malloc(sizeof *devp, M_VMPGDATA, M_WAITOK);
+		if (devp == NULL) {
+			free((caddr_t)pager, M_VMPAGER);
+			return(NULL);
+		}
+		pager->pg_handle = handle;
+		pager->pg_ops = &devicepagerops;
+		pager->pg_type = PG_DEVICE;
+		pager->pg_flags = 0;
+		pager->pg_data = devp;
+		TAILQ_INIT(&devp->devp_pglist);
+		/*
+		 * Allocate object and associate it with the pager.
+		 */
+		object = devp->devp_object = vm_object_allocate(0);
+		vm_object_enter(object, pager);
+		vm_object_setpager(object, pager, (vm_offset_t)0, FALSE);
+		/*
+		 * Finally, put it on the managed list so other can find it.
+		 * First we re-lookup in case someone else beat us to this
+		 * point (due to blocking in the various mallocs).  If so,
+		 * we free everything and start over.
+		 */
+		if (vm_pager_lookup(&dev_pager_list, handle)) {
+			free((caddr_t)devp, M_VMPGDATA);
+			free((caddr_t)pager, M_VMPAGER);
+			goto top;
+		}
+		TAILQ_INSERT_TAIL(&dev_pager_list, pager, pg_list);
+#ifdef DEBUG
+		if (dpagerdebug & DDB_ALLOC) {
+			printf("dev_pager_alloc: pager %x devp %x object %x\n",
+			       pager, devp, object);
+			vm_object_print(object, FALSE);
+		}
+#endif
+	} else {
+		/*
+		 * vm_object_lookup() gains a reference and also
+		 * removes the object from the cache.
+		 */
+		object = vm_object_lookup(pager);
+#ifdef DIAGNOSTIC
+		devp = (dev_pager_t)pager->pg_data;
+		if (object != devp->devp_object)
+			panic("dev_pager_setup: bad object");
+#endif
+	}
+	return(pager);
+}
+
+static void
+dev_pager_dealloc(pager)
+	vm_pager_t pager;
+{
+	dev_pager_t devp;
+	vm_object_t object;
+	vm_page_t m;
+
+#ifdef DEBUG
+	if (dpagerdebug & DDB_FOLLOW)
+		printf("dev_pager_dealloc(%x)\n", pager);
+#endif
+	TAILQ_REMOVE(&dev_pager_list, pager, pg_list);
+	/*
+	 * Get the object.
+	 * Note: cannot use vm_object_lookup since object has already
+	 * been removed from the hash chain.
+	 */
+	devp = (dev_pager_t)pager->pg_data;
+	object = devp->devp_object;
+#ifdef DEBUG
+	if (dpagerdebug & DDB_ALLOC)
+		printf("dev_pager_dealloc: devp %x object %x\n", devp, object);
+#endif
+	/*
+	 * Free up our fake pages.
+	 */
+	while ((m = devp->devp_pglist.tqh_first) != NULL) {
+		TAILQ_REMOVE(&devp->devp_pglist, m, pageq);
+		dev_pager_putfake(m);
+	}
+	free((caddr_t)devp, M_VMPGDATA);
+	free((caddr_t)pager, M_VMPAGER);
+}
+
+static int
+dev_pager_getpage(pager, mlist, npages, sync)
+	vm_pager_t pager;
+	vm_page_t *mlist;
+	int npages;
+	boolean_t sync;
+{
+	register vm_object_t object;
+	vm_offset_t offset, paddr;
+	vm_page_t page;
+	dev_t dev;
+	int (*mapfunc)(), prot;
+	vm_page_t m;
+
+#ifdef DEBUG
+	if (dpagerdebug & DDB_FOLLOW)
+		printf("dev_pager_getpage(%x, %x, %x, %x)\n",
+		       pager, mlist, npages, sync);
+#endif
+
+	if (npages != 1)
+		panic("dev_pager_getpage: cannot handle multiple pages");
+	m = *mlist;
+
+	object = m->object;
+	dev = (dev_t)pager->pg_handle;
+	offset = m->offset + object->paging_offset;
+	prot = PROT_READ;	/* XXX should pass in? */
+	mapfunc = cdevsw[major(dev)].d_mmap;
+#ifdef DIAGNOSTIC
+	if (mapfunc == NULL || mapfunc == enodev || mapfunc == nullop)
+		panic("dev_pager_getpage: no map function");
+#endif
+	paddr = pmap_phys_address((*mapfunc)(dev, (int)offset, prot));
+#ifdef DIAGNOSTIC
+	if (paddr == -1)
+		panic("dev_pager_getpage: map function returns error");
+#endif
+	/*
+	 * Replace the passed in page with our own fake page and free
+	 * up the original.
+	 */
+	page = dev_pager_getfake(paddr);
+	TAILQ_INSERT_TAIL(&((dev_pager_t)pager->pg_data)->devp_pglist, page,
+	    pageq);
+	vm_object_lock(object);
+	vm_page_lock_queues();
+	vm_page_free(m);
+	vm_page_insert(page, object, offset);
+	vm_page_unlock_queues();
+	PAGE_WAKEUP(m);
+	if (offset + PAGE_SIZE > object->size)
+		object->size = offset + PAGE_SIZE;	/* XXX anal */
+	vm_object_unlock(object);
+
+	return(VM_PAGER_OK);
+}
+
+static int
+dev_pager_putpage(pager, mlist, npages, sync)
+	vm_pager_t pager;
+	vm_page_t *mlist;
+	int npages;
+	boolean_t sync;
+{
+#ifdef DEBUG
+	if (dpagerdebug & DDB_FOLLOW)
+		printf("dev_pager_putpage(%x, %x, %x, %x)\n",
+		       pager, mlist, npages, sync);
+#endif
+	if (pager == NULL)
+		return;
+	panic("dev_pager_putpage called");
+}
+
+static boolean_t
+dev_pager_haspage(pager, offset)
+	vm_pager_t pager;
+	vm_offset_t offset;
+{
+#ifdef DEBUG
+	if (dpagerdebug & DDB_FOLLOW)
+		printf("dev_pager_haspage(%x, %x)\n", pager, offset);
+#endif
+	return(TRUE);
+}
+
+static vm_page_t
+dev_pager_getfake(paddr)
+	vm_offset_t paddr;
+{
+	vm_page_t m;
+	int i;
+
+	if (dev_pager_fakelist.tqh_first == NULL) {
+		m = (vm_page_t)malloc(PAGE_SIZE, M_VMPGDATA, M_WAITOK);
+		for (i = PAGE_SIZE / sizeof(*m); i > 0; i--) {
+			TAILQ_INSERT_TAIL(&dev_pager_fakelist, m, pageq);
+			m++;
+		}
+	}
+	m = dev_pager_fakelist.tqh_first;
+	TAILQ_REMOVE(&dev_pager_fakelist, m, pageq);
+	m->flags = PG_BUSY | PG_CLEAN | PG_FAKE | PG_FICTITIOUS;
+	m->phys_addr = paddr;
+	m->wire_count = 1;
+	return(m);
+}
+
+static void
+dev_pager_putfake(m)
+	vm_page_t m;
+{
+#ifdef DIAGNOSTIC
+	if (!(m->flags & PG_FICTITIOUS))
+		panic("dev_pager_putfake: bad page");
+#endif
+	TAILQ_INSERT_TAIL(&dev_pager_fakelist, m, pageq);
+}
diff --git a/sys/vm/device_pager.h b/sys/vm/device_pager.h
new file mode 100644
index 0000000..88406229
--- /dev/null
+++ b/sys/vm/device_pager.h
@@ -0,0 +1,53 @@
+/*
+ * Copyright (c) 1990 University of Utah.
+ * Copyright (c) 1991, 1993
+ *	The Regents of the University of California.  All rights reserved.
+ *
+ * This code is derived from software contributed to Berkeley by
+ * the Systems Programming Group of the University of Utah Computer
+ * Science Department.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. All advertising materials mentioning features or use of this software
+ *    must display the following acknowledgement:
+ *	This product includes software developed by the University of
+ *	California, Berkeley and its contributors.
+ * 4. Neither the name of the University nor the names of its contributors
+ *    may be used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ *
+ *	@(#)device_pager.h	8.3 (Berkeley) 12/13/93
+ */
+
+#ifndef	_DEVICE_PAGER_
+#define	_DEVICE_PAGER_	1
+
+/*
+ * Device pager private data.
+ */
+struct devpager {
+	struct pglist	devp_pglist;	/* list of pages allocated */
+	vm_object_t	devp_object;	/* object representing this device */
+};
+typedef struct devpager	*dev_pager_t;
+
+#endif	/* _DEVICE_PAGER_ */
diff --git a/sys/vm/kern_lock.c b/sys/vm/kern_lock.c
new file mode 100644
index 0000000..c4fa052
--- /dev/null
+++ b/sys/vm/kern_lock.c
@@ -0,0 +1,534 @@
+/* 
+ * Copyright (c) 1991, 1993
+ *	The Regents of the University of California.  All rights reserved.
+ *
+ * This code is derived from software contributed to Berkeley by
+ * The Mach Operating System project at Carnegie-Mellon University.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. All advertising materials mentioning features or use of this software
+ *    must display the following acknowledgement:
+ *	This product includes software developed by the University of
+ *	California, Berkeley and its contributors.
+ * 4. Neither the name of the University nor the names of its contributors
+ *    may be used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ *
+ *	@(#)kern_lock.c	8.1 (Berkeley) 6/11/93
+ *
+ *
+ * Copyright (c) 1987, 1990 Carnegie-Mellon University.
+ * All rights reserved.
+ *
+ * Authors: Avadis Tevanian, Jr., Michael Wayne Young
+ * 
+ * Permission to use, copy, modify and distribute this software and
+ * its documentation is hereby granted, provided that both the copyright
+ * notice and this permission notice appear in all copies of the
+ * software, derivative works or modified versions, and any portions
+ * thereof, and that both notices appear in supporting documentation.
+ * 
+ * CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS" 
+ * CONDITION.  CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND 
+ * FOR ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
+ * 
+ * Carnegie Mellon requests users of this software to return to
+ *
+ *  Software Distribution Coordinator  or  Software.Distribution@CS.CMU.EDU
+ *  School of Computer Science
+ *  Carnegie Mellon University
+ *  Pittsburgh PA 15213-3890
+ *
+ * any improvements or extensions that they make and grant Carnegie the
+ * rights to redistribute these changes.
+ */
+
+/*
+ *	Locking primitives implementation
+ */
+
+#include <sys/param.h>
+#include <sys/systm.h>
+
+#include <vm/vm.h>
+
+/* XXX */
+#include <sys/proc.h>
+typedef	int *thread_t;
+#define	current_thread()	((thread_t)&curproc->p_thread)
+/* XXX */
+
+#if	NCPUS > 1
+
+/*
+ *	Module:		lock
+ *	Function:
+ *		Provide reader/writer sychronization.
+ *	Implementation:
+ *		Simple interlock on a bit.  Readers first interlock
+ *		increment the reader count, then let go.  Writers hold
+ *		the interlock (thus preventing further readers), and
+ *		wait for already-accepted readers to go away.
+ */
+
+/*
+ *	The simple-lock routines are the primitives out of which
+ *	the lock package is built.  The implementation is left
+ *	to the machine-dependent code.
+ */
+
+#ifdef	notdef
+/*
+ *	A sample implementation of simple locks.
+ *	assumes:
+ *		boolean_t test_and_set(boolean_t *)
+ *			indivisibly sets the boolean to TRUE
+ *			and returns its old value
+ *		and that setting a boolean to FALSE is indivisible.
+ */
+/*
+ *	simple_lock_init initializes a simple lock.  A simple lock
+ *	may only be used for exclusive locks.
+ */
+
+void simple_lock_init(l)
+	simple_lock_t	l;
+{
+	*(boolean_t *)l = FALSE;
+}
+
+void simple_lock(l)
+	simple_lock_t	l;
+{
+	while (test_and_set((boolean_t *)l))
+		continue;
+}
+
+void simple_unlock(l)
+	simple_lock_t	l;
+{
+	*(boolean_t *)l = FALSE;
+}
+
+boolean_t simple_lock_try(l)
+	simple_lock_t	l;
+{
+    	return (!test_and_set((boolean_t *)l));
+}
+#endif /* notdef */
+#endif /* NCPUS > 1 */
+
+#if	NCPUS > 1
+int lock_wait_time = 100;
+#else /* NCPUS > 1 */
+
+	/*
+	 * 	It is silly to spin on a uni-processor as if we
+	 *	thought something magical would happen to the
+	 *	want_write bit while we are executing.
+	 */
+int lock_wait_time = 0;
+#endif /* NCPUS > 1 */
+
+
+/*
+ *	Routine:	lock_init
+ *	Function:
+ *		Initialize a lock; required before use.
+ *		Note that clients declare the "struct lock"
+ *		variables and then initialize them, rather
+ *		than getting a new one from this module.
+ */
+void lock_init(l, can_sleep)
+	lock_t		l;
+	boolean_t	can_sleep;
+{
+	bzero(l, sizeof(lock_data_t));
+	simple_lock_init(&l->interlock);
+	l->want_write = FALSE;
+	l->want_upgrade = FALSE;
+	l->read_count = 0;
+	l->can_sleep = can_sleep;
+	l->thread = (char *)-1;		/* XXX */
+	l->recursion_depth = 0;
+}
+
+void lock_sleepable(l, can_sleep)
+	lock_t		l;
+	boolean_t	can_sleep;
+{
+	simple_lock(&l->interlock);
+	l->can_sleep = can_sleep;
+	simple_unlock(&l->interlock);
+}
+
+
+/*
+ *	Sleep locks.  These use the same data structure and algorithm
+ *	as the spin locks, but the process sleeps while it is waiting
+ *	for the lock.  These work on uniprocessor systems.
+ */
+
+void lock_write(l)
+	register lock_t	l;
+{
+	register int	i;
+
+	simple_lock(&l->interlock);
+
+	if (((thread_t)l->thread) == current_thread()) {
+		/*
+		 *	Recursive lock.
+		 */
+		l->recursion_depth++;
+		simple_unlock(&l->interlock);
+		return;
+	}
+
+	/*
+	 *	Try to acquire the want_write bit.
+	 */
+	while (l->want_write) {
+		if ((i = lock_wait_time) > 0) {
+			simple_unlock(&l->interlock);
+			while (--i > 0 && l->want_write)
+				continue;
+			simple_lock(&l->interlock);
+		}
+
+		if (l->can_sleep && l->want_write) {
+			l->waiting = TRUE;
+			thread_sleep((int) l, &l->interlock, FALSE);
+			simple_lock(&l->interlock);
+		}
+	}
+	l->want_write = TRUE;
+
+	/* Wait for readers (and upgrades) to finish */
+
+	while ((l->read_count != 0) || l->want_upgrade) {
+		if ((i = lock_wait_time) > 0) {
+			simple_unlock(&l->interlock);
+			while (--i > 0 && (l->read_count != 0 ||
+					l->want_upgrade))
+				continue;
+			simple_lock(&l->interlock);
+		}
+
+		if (l->can_sleep && (l->read_count != 0 || l->want_upgrade)) {
+			l->waiting = TRUE;
+			thread_sleep((int) l, &l->interlock, FALSE);
+			simple_lock(&l->interlock);
+		}
+	}
+	simple_unlock(&l->interlock);
+}
+
+void lock_done(l)
+	register lock_t	l;
+{
+	simple_lock(&l->interlock);
+
+	if (l->read_count != 0)
+		l->read_count--;
+	else
+	if (l->recursion_depth != 0)
+		l->recursion_depth--;
+	else
+	if (l->want_upgrade)
+	 	l->want_upgrade = FALSE;
+	else
+	 	l->want_write = FALSE;
+
+	if (l->waiting) {
+		l->waiting = FALSE;
+		thread_wakeup((int) l);
+	}
+	simple_unlock(&l->interlock);
+}
+
+void lock_read(l)
+	register lock_t	l;
+{
+	register int	i;
+
+	simple_lock(&l->interlock);
+
+	if (((thread_t)l->thread) == current_thread()) {
+		/*
+		 *	Recursive lock.
+		 */
+		l->read_count++;
+		simple_unlock(&l->interlock);
+		return;
+	}
+
+	while (l->want_write || l->want_upgrade) {
+		if ((i = lock_wait_time) > 0) {
+			simple_unlock(&l->interlock);
+			while (--i > 0 && (l->want_write || l->want_upgrade))
+				continue;
+			simple_lock(&l->interlock);
+		}
+
+		if (l->can_sleep && (l->want_write || l->want_upgrade)) {
+			l->waiting = TRUE;
+			thread_sleep((int) l, &l->interlock, FALSE);
+			simple_lock(&l->interlock);
+		}
+	}
+
+	l->read_count++;
+	simple_unlock(&l->interlock);
+}
+
+/*
+ *	Routine:	lock_read_to_write
+ *	Function:
+ *		Improves a read-only lock to one with
+ *		write permission.  If another reader has
+ *		already requested an upgrade to a write lock,
+ *		no lock is held upon return.
+ *
+ *		Returns TRUE if the upgrade *failed*.
+ */
+boolean_t lock_read_to_write(l)
+	register lock_t	l;
+{
+	register int	i;
+
+	simple_lock(&l->interlock);
+
+	l->read_count--;
+
+	if (((thread_t)l->thread) == current_thread()) {
+		/*
+		 *	Recursive lock.
+		 */
+		l->recursion_depth++;
+		simple_unlock(&l->interlock);
+		return(FALSE);
+	}
+
+	if (l->want_upgrade) {
+		/*
+		 *	Someone else has requested upgrade.
+		 *	Since we've released a read lock, wake
+		 *	him up.
+		 */
+		if (l->waiting) {
+			l->waiting = FALSE;
+			thread_wakeup((int) l);
+		}
+
+		simple_unlock(&l->interlock);
+		return (TRUE);
+	}
+
+	l->want_upgrade = TRUE;
+
+	while (l->read_count != 0) {
+		if ((i = lock_wait_time) > 0) {
+			simple_unlock(&l->interlock);
+			while (--i > 0 && l->read_count != 0)
+				continue;
+			simple_lock(&l->interlock);
+		}
+
+		if (l->can_sleep && l->read_count != 0) {
+			l->waiting = TRUE;
+			thread_sleep((int) l, &l->interlock, FALSE);
+			simple_lock(&l->interlock);
+		}
+	}
+
+	simple_unlock(&l->interlock);
+	return (FALSE);
+}
+
+void lock_write_to_read(l)
+	register lock_t	l;
+{
+	simple_lock(&l->interlock);
+
+	l->read_count++;
+	if (l->recursion_depth != 0)
+		l->recursion_depth--;
+	else
+	if (l->want_upgrade)
+		l->want_upgrade = FALSE;
+	else
+	 	l->want_write = FALSE;
+
+	if (l->waiting) {
+		l->waiting = FALSE;
+		thread_wakeup((int) l);
+	}
+
+	simple_unlock(&l->interlock);
+}
+
+
+/*
+ *	Routine:	lock_try_write
+ *	Function:
+ *		Tries to get a write lock.
+ *
+ *		Returns FALSE if the lock is not held on return.
+ */
+
+boolean_t lock_try_write(l)
+	register lock_t	l;
+{
+
+	simple_lock(&l->interlock);
+
+	if (((thread_t)l->thread) == current_thread()) {
+		/*
+		 *	Recursive lock
+		 */
+		l->recursion_depth++;
+		simple_unlock(&l->interlock);
+		return(TRUE);
+	}
+
+	if (l->want_write || l->want_upgrade || l->read_count) {
+		/*
+		 *	Can't get lock.
+		 */
+		simple_unlock(&l->interlock);
+		return(FALSE);
+	}
+
+	/*
+	 *	Have lock.
+	 */
+
+	l->want_write = TRUE;
+	simple_unlock(&l->interlock);
+	return(TRUE);
+}
+
+/*
+ *	Routine:	lock_try_read
+ *	Function:
+ *		Tries to get a read lock.
+ *
+ *		Returns FALSE if the lock is not held on return.
+ */
+
+boolean_t lock_try_read(l)
+	register lock_t	l;
+{
+	simple_lock(&l->interlock);
+
+	if (((thread_t)l->thread) == current_thread()) {
+		/*
+		 *	Recursive lock
+		 */
+		l->read_count++;
+		simple_unlock(&l->interlock);
+		return(TRUE);
+	}
+
+	if (l->want_write || l->want_upgrade) {
+		simple_unlock(&l->interlock);
+		return(FALSE);
+	}
+
+	l->read_count++;
+	simple_unlock(&l->interlock);
+	return(TRUE);
+}
+
+/*
+ *	Routine:	lock_try_read_to_write
+ *	Function:
+ *		Improves a read-only lock to one with
+ *		write permission.  If another reader has
+ *		already requested an upgrade to a write lock,
+ *		the read lock is still held upon return.
+ *
+ *		Returns FALSE if the upgrade *failed*.
+ */
+boolean_t lock_try_read_to_write(l)
+	register lock_t	l;
+{
+
+	simple_lock(&l->interlock);
+
+	if (((thread_t)l->thread) == current_thread()) {
+		/*
+		 *	Recursive lock
+		 */
+		l->read_count--;
+		l->recursion_depth++;
+		simple_unlock(&l->interlock);
+		return(TRUE);
+	}
+
+	if (l->want_upgrade) {
+		simple_unlock(&l->interlock);
+		return(FALSE);
+	}
+	l->want_upgrade = TRUE;
+	l->read_count--;
+
+	while (l->read_count != 0) {
+		l->waiting = TRUE;
+		thread_sleep((int) l, &l->interlock, FALSE);
+		simple_lock(&l->interlock);
+	}
+
+	simple_unlock(&l->interlock);
+	return(TRUE);
+}
+
+/*
+ *	Allow a process that has a lock for write to acquire it
+ *	recursively (for read, write, or update).
+ */
+void lock_set_recursive(l)
+	lock_t		l;
+{
+	simple_lock(&l->interlock);
+	if (!l->want_write) {
+		panic("lock_set_recursive: don't have write lock");
+	}
+	l->thread = (char *) current_thread();
+	simple_unlock(&l->interlock);
+}
+
+/*
+ *	Prevent a lock from being re-acquired.
+ */
+void lock_clear_recursive(l)
+	lock_t		l;
+{
+	simple_lock(&l->interlock);
+	if (((thread_t) l->thread) != current_thread()) {
+		panic("lock_clear_recursive: wrong thread");
+	}
+	if (l->recursion_depth == 0)
+		l->thread = (char *)-1;		/* XXX */
+	simple_unlock(&l->interlock);
+}
diff --git a/sys/vm/lock.h b/sys/vm/lock.h
new file mode 100644
index 0000000..26bed1f
--- /dev/null
+++ b/sys/vm/lock.h
@@ -0,0 +1,172 @@
+/* 
+ * Copyright (c) 1991, 1993
+ *	The Regents of the University of California.  All rights reserved.
+ *
+ * This code is derived from software contributed to Berkeley by
+ * The Mach Operating System project at Carnegie-Mellon University.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. All advertising materials mentioning features or use of this software
+ *    must display the following acknowledgement:
+ *	This product includes software developed by the University of
+ *	California, Berkeley and its contributors.
+ * 4. Neither the name of the University nor the names of its contributors
+ *    may be used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ *
+ *	@(#)lock.h	8.1 (Berkeley) 6/11/93
+ *
+ *
+ * Copyright (c) 1987, 1990 Carnegie-Mellon University.
+ * All rights reserved.
+ *
+ * Authors: Avadis Tevanian, Jr., Michael Wayne Young
+ * 
+ * Permission to use, copy, modify and distribute this software and
+ * its documentation is hereby granted, provided that both the copyright
+ * notice and this permission notice appear in all copies of the
+ * software, derivative works or modified versions, and any portions
+ * thereof, and that both notices appear in supporting documentation.
+ * 
+ * CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS" 
+ * CONDITION.  CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND 
+ * FOR ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
+ * 
+ * Carnegie Mellon requests users of this software to return to
+ *
+ *  Software Distribution Coordinator  or  Software.Distribution@CS.CMU.EDU
+ *  School of Computer Science
+ *  Carnegie Mellon University
+ *  Pittsburgh PA 15213-3890
+ *
+ * any improvements or extensions that they make and grant Carnegie the
+ * rights to redistribute these changes.
+ */
+
+/*
+ *	Locking primitives definitions
+ */
+
+#ifndef	_LOCK_H_
+#define	_LOCK_H_
+
+#define	NCPUS	1		/* XXX */
+
+/*
+ *	A simple spin lock.
+ */
+
+struct slock {
+	int		lock_data;	/* in general 1 bit is sufficient */
+};
+
+typedef struct slock	simple_lock_data_t;
+typedef struct slock	*simple_lock_t;
+
+/*
+ *	The general lock structure.  Provides for multiple readers,
+ *	upgrading from read to write, and sleeping until the lock
+ *	can be gained.
+ */
+
+struct lock {
+#ifdef	vax
+	/*
+	 *	Efficient VAX implementation -- see field description below.
+	 */
+	unsigned int	read_count:16,
+			want_upgrade:1,
+			want_write:1,
+			waiting:1,
+			can_sleep:1,
+			:0;
+
+	simple_lock_data_t	interlock;
+#else /* vax */
+#ifdef	ns32000
+	/*
+	 *	Efficient ns32000 implementation --
+	 *	see field description below.
+	 */
+	simple_lock_data_t	interlock;
+	unsigned int	read_count:16,
+			want_upgrade:1,
+			want_write:1,
+			waiting:1,
+			can_sleep:1,
+			:0;
+
+#else /* ns32000 */
+	/*	Only the "interlock" field is used for hardware exclusion;
+	 *	other fields are modified with normal instructions after
+	 *	acquiring the interlock bit.
+	 */
+	simple_lock_data_t
+			interlock;	/* Interlock for remaining fields */
+	boolean_t	want_write;	/* Writer is waiting, or locked for write */
+	boolean_t	want_upgrade;	/* Read-to-write upgrade waiting */
+	boolean_t	waiting;	/* Someone is sleeping on lock */
+	boolean_t	can_sleep;	/* Can attempts to lock go to sleep */
+	int		read_count;	/* Number of accepted readers */
+#endif	/* ns32000 */
+#endif	/* vax */
+	char		*thread;	/* Thread that has lock, if recursive locking allowed */
+					/* (should be thread_t, but but we then have mutually
+					   recursive definitions) */
+	int		recursion_depth;/* Depth of recursion */
+};
+
+typedef struct lock	lock_data_t;
+typedef struct lock	*lock_t;
+
+#if NCPUS > 1
+__BEGIN_DECLS
+void		simple_lock __P((simple_lock_t));
+void		simple_lock_init __P((simple_lock_t));
+boolean_t	simple_lock_try __P((simple_lock_t));
+void		simple_unlock __P((simple_lock_t));
+__END_DECLS
+#else		/* No multiprocessor locking is necessary. */
+#define	simple_lock(l)
+#define	simple_lock_init(l)
+#define	simple_lock_try(l)	(1)	/* Always succeeds. */
+#define	simple_unlock(l)
+#endif
+
+/* Sleep locks must work even if no multiprocessing. */
+
+#define	lock_read_done(l)	lock_done(l)
+#define	lock_write_done(l)	lock_done(l)
+
+void		lock_clear_recursive __P((lock_t));
+void		lock_done __P((lock_t));
+void		lock_init __P((lock_t, boolean_t));
+void		lock_read __P((lock_t));
+boolean_t	lock_read_to_write __P((lock_t));
+void		lock_set_recursive __P((lock_t));
+void		lock_sleepable __P((lock_t, boolean_t));
+boolean_t	lock_try_read __P((lock_t));
+boolean_t	lock_try_read_to_write __P((lock_t));
+boolean_t	lock_try_write __P((lock_t));
+void		lock_write __P((lock_t));
+void		lock_write_to_read __P((lock_t));
+#endif /* !_LOCK_H_ */
diff --git a/sys/vm/pmap.h b/sys/vm/pmap.h
new file mode 100644
index 0000000..63a83c9
--- /dev/null
+++ b/sys/vm/pmap.h
@@ -0,0 +1,122 @@
+/* 
+ * Copyright (c) 1991, 1993
+ *	The Regents of the University of California.  All rights reserved.
+ *
+ * This code is derived from software contributed to Berkeley by
+ * The Mach Operating System project at Carnegie-Mellon University.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. All advertising materials mentioning features or use of this software
+ *    must display the following acknowledgement:
+ *	This product includes software developed by the University of
+ *	California, Berkeley and its contributors.
+ * 4. Neither the name of the University nor the names of its contributors
+ *    may be used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ *
+ *	@(#)pmap.h	8.1 (Berkeley) 6/11/93
+ *
+ *
+ * Copyright (c) 1987, 1990 Carnegie-Mellon University.
+ * All rights reserved.
+ *
+ * Author: Avadis Tevanian, Jr.
+ * 
+ * Permission to use, copy, modify and distribute this software and
+ * its documentation is hereby granted, provided that both the copyright
+ * notice and this permission notice appear in all copies of the
+ * software, derivative works or modified versions, and any portions
+ * thereof, and that both notices appear in supporting documentation.
+ * 
+ * CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS" 
+ * CONDITION.  CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND 
+ * FOR ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
+ * 
+ * Carnegie Mellon requests users of this software to return to
+ *
+ *  Software Distribution Coordinator  or  Software.Distribution@CS.CMU.EDU
+ *  School of Computer Science
+ *  Carnegie Mellon University
+ *  Pittsburgh PA 15213-3890
+ *
+ * any improvements or extensions that they make and grant Carnegie the
+ * rights to redistribute these changes.
+ */
+
+/*
+ *	Machine address mapping definitions -- machine-independent
+ *	section.  [For machine-dependent section, see "machine/pmap.h".]
+ */
+
+#ifndef	_PMAP_VM_
+#define	_PMAP_VM_
+
+/*
+ * Each machine dependent implementation is expected to
+ * keep certain statistics.  They may do this anyway they
+ * so choose, but are expected to return the statistics
+ * in the following structure.
+ */
+struct pmap_statistics {
+	long		resident_count;	/* # of pages mapped (total)*/
+	long		wired_count;	/* # of pages wired */
+};
+typedef struct pmap_statistics	*pmap_statistics_t;
+
+#include <machine/pmap.h>
+
+#ifdef KERNEL
+__BEGIN_DECLS
+void		*pmap_bootstrap_alloc __P((int));
+void		 pmap_bootstrap( /* machine dependent */ );
+void		 pmap_change_wiring __P((pmap_t, vm_offset_t, boolean_t));
+void		 pmap_clear_modify __P((vm_offset_t pa));
+void		 pmap_clear_reference __P((vm_offset_t pa));
+void		 pmap_collect __P((pmap_t));
+void		 pmap_copy __P((pmap_t,
+		    pmap_t, vm_offset_t, vm_size_t, vm_offset_t));
+void		 pmap_copy_page __P((vm_offset_t, vm_offset_t));
+pmap_t		 pmap_create __P((vm_size_t));
+void		 pmap_destroy __P((pmap_t));
+void		 pmap_enter __P((pmap_t,
+		    vm_offset_t, vm_offset_t, vm_prot_t, boolean_t));
+vm_offset_t	 pmap_extract __P((pmap_t, vm_offset_t));
+void		 pmap_init __P((vm_offset_t, vm_offset_t));
+boolean_t	 pmap_is_modified __P((vm_offset_t pa));
+boolean_t	 pmap_is_referenced __P((vm_offset_t pa));
+vm_offset_t	 pmap_map __P((vm_offset_t, vm_offset_t, vm_offset_t, int));
+void		 pmap_page_protect __P((vm_offset_t, vm_prot_t));
+void		 pmap_pageable __P((pmap_t,
+		    vm_offset_t, vm_offset_t, boolean_t));
+vm_offset_t	 pmap_phys_address __P((int));
+void		 pmap_pinit __P((pmap_t));
+void		 pmap_protect __P((pmap_t,
+		    vm_offset_t, vm_offset_t, vm_prot_t));
+void		 pmap_reference __P((pmap_t));
+void		 pmap_release __P((pmap_t));
+void		 pmap_remove __P((pmap_t, vm_offset_t, vm_offset_t));
+void		 pmap_update __P((void));
+void		 pmap_zero_page __P((vm_offset_t));
+__END_DECLS
+#endif
+
+#endif /* _PMAP_VM_ */
diff --git a/sys/vm/swap_pager.c b/sys/vm/swap_pager.c
new file mode 100644
index 0000000..899a6cf
--- /dev/null
+++ b/sys/vm/swap_pager.c
@@ -0,0 +1,1009 @@
+/*
+ * Copyright (c) 1990 University of Utah.
+ * Copyright (c) 1991, 1993
+ *	The Regents of the University of California.  All rights reserved.
+ *
+ * This code is derived from software contributed to Berkeley by
+ * the Systems Programming Group of the University of Utah Computer
+ * Science Department.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. All advertising materials mentioning features or use of this software
+ *    must display the following acknowledgement:
+ *	This product includes software developed by the University of
+ *	California, Berkeley and its contributors.
+ * 4. Neither the name of the University nor the names of its contributors
+ *    may be used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ *
+ * from: Utah $Hdr: swap_pager.c 1.4 91/04/30$
+ *
+ *	@(#)swap_pager.c	8.9 (Berkeley) 3/21/94
+ */
+
+/*
+ * Quick hack to page to dedicated partition(s).
+ * TODO:
+ *	Add multiprocessor locks
+ *	Deal with async writes in a better fashion
+ */
+
+#include <sys/param.h>
+#include <sys/systm.h>
+#include <sys/proc.h>
+#include <sys/buf.h>
+#include <sys/map.h>
+#include <sys/vnode.h>
+#include <sys/malloc.h>
+
+#include <miscfs/specfs/specdev.h>
+
+#include <vm/vm.h>
+#include <vm/vm_page.h>
+#include <vm/vm_pageout.h>
+#include <vm/swap_pager.h>
+
+#define NSWSIZES	16	/* size of swtab */
+#define MAXDADDRS	64	/* max # of disk addrs for fixed allocations */
+#ifndef NPENDINGIO
+#define NPENDINGIO	64	/* max # of pending cleans */
+#endif
+
+#ifdef DEBUG
+int	swpagerdebug = 0x100;
+#define	SDB_FOLLOW	0x001
+#define SDB_INIT	0x002
+#define SDB_ALLOC	0x004
+#define SDB_IO		0x008
+#define SDB_WRITE	0x010
+#define SDB_FAIL	0x020
+#define SDB_ALLOCBLK	0x040
+#define SDB_FULL	0x080
+#define SDB_ANOM	0x100
+#define SDB_ANOMPANIC	0x200
+#define SDB_CLUSTER	0x400
+#define SDB_PARANOIA	0x800
+#endif
+
+TAILQ_HEAD(swpclean, swpagerclean);
+
+struct swpagerclean {
+	TAILQ_ENTRY(swpagerclean)	spc_list;
+	int				spc_flags;
+	struct buf			*spc_bp;
+	sw_pager_t			spc_swp;
+	vm_offset_t			spc_kva;
+	vm_page_t			spc_m;
+	int				spc_npages;
+} swcleanlist[NPENDINGIO];
+typedef struct swpagerclean *swp_clean_t;
+
+/* spc_flags values */
+#define SPC_FREE	0x00
+#define SPC_BUSY	0x01
+#define SPC_DONE	0x02
+#define SPC_ERROR	0x04
+
+struct swtab {
+	vm_size_t st_osize;	/* size of object (bytes) */
+	int	  st_bsize;	/* vs. size of swap block (DEV_BSIZE units) */
+#ifdef DEBUG
+	u_long	  st_inuse;	/* number in this range in use */
+	u_long	  st_usecnt;	/* total used of this size */
+#endif
+} swtab[NSWSIZES+1];
+
+#ifdef DEBUG
+int		swap_pager_poip;	/* pageouts in progress */
+int		swap_pager_piip;	/* pageins in progress */
+#endif
+
+int		swap_pager_maxcluster;	/* maximum cluster size */
+int		swap_pager_npendingio;	/* number of pager clean structs */
+
+struct swpclean	swap_pager_inuse;	/* list of pending page cleans */
+struct swpclean	swap_pager_free;	/* list of free pager clean structs */
+struct pagerlst	swap_pager_list;	/* list of "named" anon regions */
+
+static void 		swap_pager_init __P((void));
+static vm_pager_t	swap_pager_alloc
+			    __P((caddr_t, vm_size_t, vm_prot_t, vm_offset_t));
+static void		swap_pager_clean __P((int));
+#ifdef DEBUG
+static void		swap_pager_clean_check __P((vm_page_t *, int, int));
+#endif
+static void		swap_pager_cluster
+			    __P((vm_pager_t, vm_offset_t,
+				 vm_offset_t *, vm_offset_t *));
+static void		swap_pager_dealloc __P((vm_pager_t));
+static int		swap_pager_getpage
+			    __P((vm_pager_t, vm_page_t *, int, boolean_t));
+static boolean_t	swap_pager_haspage __P((vm_pager_t, vm_offset_t));
+static int		swap_pager_io __P((sw_pager_t, vm_page_t *, int, int));
+static void		swap_pager_iodone __P((struct buf *));
+static int		swap_pager_putpage
+			    __P((vm_pager_t, vm_page_t *, int, boolean_t));
+
+struct pagerops swappagerops = {
+	swap_pager_init,
+	swap_pager_alloc,
+	swap_pager_dealloc,
+	swap_pager_getpage,
+	swap_pager_putpage,
+	swap_pager_haspage,
+	swap_pager_cluster
+};
+
+static void
+swap_pager_init()
+{
+	register swp_clean_t spc;
+	register int i, bsize;
+	extern int dmmin, dmmax;
+	int maxbsize;
+
+#ifdef DEBUG
+	if (swpagerdebug & (SDB_FOLLOW|SDB_INIT))
+		printf("swpg_init()\n");
+#endif
+	dfltpagerops = &swappagerops;
+	TAILQ_INIT(&swap_pager_list);
+
+	/*
+	 * Allocate async IO structures.
+	 *
+	 * XXX it would be nice if we could do this dynamically based on
+	 * the value of nswbuf (since we are ultimately limited by that)
+	 * but neither nswbuf or malloc has been initialized yet.  So the
+	 * structs are statically allocated above.
+	 */
+	swap_pager_npendingio = NPENDINGIO;
+
+	/*
+	 * Initialize clean lists
+	 */
+	TAILQ_INIT(&swap_pager_inuse);
+	TAILQ_INIT(&swap_pager_free);
+	for (i = 0, spc = swcleanlist; i < swap_pager_npendingio; i++, spc++) {
+		TAILQ_INSERT_TAIL(&swap_pager_free, spc, spc_list);
+		spc->spc_flags = SPC_FREE;
+	}
+
+	/*
+	 * Calculate the swap allocation constants.
+	 */
+        if (dmmin == 0) {
+                dmmin = DMMIN;
+		if (dmmin < CLBYTES/DEV_BSIZE)
+			dmmin = CLBYTES/DEV_BSIZE;
+	}
+        if (dmmax == 0)
+                dmmax = DMMAX;
+
+	/*
+	 * Fill in our table of object size vs. allocation size
+	 */
+	bsize = btodb(PAGE_SIZE);
+	if (bsize < dmmin)
+		bsize = dmmin;
+	maxbsize = btodb(sizeof(sw_bm_t) * NBBY * PAGE_SIZE);
+	if (maxbsize > dmmax)
+		maxbsize = dmmax;
+	for (i = 0; i < NSWSIZES; i++) {
+		swtab[i].st_osize = (vm_size_t) (MAXDADDRS * dbtob(bsize));
+		swtab[i].st_bsize = bsize;
+		if (bsize <= btodb(MAXPHYS))
+			swap_pager_maxcluster = dbtob(bsize);
+#ifdef DEBUG
+		if (swpagerdebug & SDB_INIT)
+			printf("swpg_init: ix %d, size %x, bsize %x\n",
+			       i, swtab[i].st_osize, swtab[i].st_bsize);
+#endif
+		if (bsize >= maxbsize)
+			break;
+		bsize *= 2;
+	}
+	swtab[i].st_osize = 0;
+	swtab[i].st_bsize = bsize;
+}
+
+/*
+ * Allocate a pager structure and associated resources.
+ * Note that if we are called from the pageout daemon (handle == NULL)
+ * we should not wait for memory as it could resulting in deadlock.
+ */
+static vm_pager_t
+swap_pager_alloc(handle, size, prot, foff)
+	caddr_t handle;
+	register vm_size_t size;
+	vm_prot_t prot;
+	vm_offset_t foff;
+{
+	register vm_pager_t pager;
+	register sw_pager_t swp;
+	struct swtab *swt;
+	int waitok;
+
+#ifdef DEBUG
+	if (swpagerdebug & (SDB_FOLLOW|SDB_ALLOC))
+		printf("swpg_alloc(%x, %x, %x)\n", handle, size, prot);
+#endif
+	/*
+	 * If this is a "named" anonymous region, look it up and
+	 * return the appropriate pager if it exists.
+	 */
+	if (handle) {
+		pager = vm_pager_lookup(&swap_pager_list, handle);
+		if (pager != NULL) {
+			/*
+			 * Use vm_object_lookup to gain a reference
+			 * to the object and also to remove from the
+			 * object cache.
+			 */
+			if (vm_object_lookup(pager) == NULL)
+				panic("swap_pager_alloc: bad object");
+			return(pager);
+		}
+	}
+	/*
+	 * Pager doesn't exist, allocate swap management resources
+	 * and initialize.
+	 */
+	waitok = handle ? M_WAITOK : M_NOWAIT;
+	pager = (vm_pager_t)malloc(sizeof *pager, M_VMPAGER, waitok);
+	if (pager == NULL)
+		return(NULL);
+	swp = (sw_pager_t)malloc(sizeof *swp, M_VMPGDATA, waitok);
+	if (swp == NULL) {
+#ifdef DEBUG
+		if (swpagerdebug & SDB_FAIL)
+			printf("swpg_alloc: swpager malloc failed\n");
+#endif
+		free((caddr_t)pager, M_VMPAGER);
+		return(NULL);
+	}
+	size = round_page(size);
+	for (swt = swtab; swt->st_osize; swt++)
+		if (size <= swt->st_osize)
+			break;
+#ifdef DEBUG
+	swt->st_inuse++;
+	swt->st_usecnt++;
+#endif
+	swp->sw_osize = size;
+	swp->sw_bsize = swt->st_bsize;
+	swp->sw_nblocks = (btodb(size) + swp->sw_bsize - 1) / swp->sw_bsize;
+	swp->sw_blocks = (sw_blk_t)
+		malloc(swp->sw_nblocks*sizeof(*swp->sw_blocks),
+		       M_VMPGDATA, M_NOWAIT);
+	if (swp->sw_blocks == NULL) {
+		free((caddr_t)swp, M_VMPGDATA);
+		free((caddr_t)pager, M_VMPAGER);
+#ifdef DEBUG
+		if (swpagerdebug & SDB_FAIL)
+			printf("swpg_alloc: sw_blocks malloc failed\n");
+		swt->st_inuse--;
+		swt->st_usecnt--;
+#endif
+		return(FALSE);
+	}
+	bzero((caddr_t)swp->sw_blocks,
+	      swp->sw_nblocks * sizeof(*swp->sw_blocks));
+	swp->sw_poip = 0;
+	if (handle) {
+		vm_object_t object;
+
+		swp->sw_flags = SW_NAMED;
+		TAILQ_INSERT_TAIL(&swap_pager_list, pager, pg_list);
+		/*
+		 * Consistant with other pagers: return with object
+		 * referenced.  Can't do this with handle == NULL
+		 * since it might be the pageout daemon calling.
+		 */
+		object = vm_object_allocate(size);
+		vm_object_enter(object, pager);
+		vm_object_setpager(object, pager, 0, FALSE);
+	} else {
+		swp->sw_flags = 0;
+		pager->pg_list.tqe_next = NULL;
+		pager->pg_list.tqe_prev = NULL;
+	}
+	pager->pg_handle = handle;
+	pager->pg_ops = &swappagerops;
+	pager->pg_type = PG_SWAP;
+	pager->pg_flags = PG_CLUSTERPUT;
+	pager->pg_data = swp;
+
+#ifdef DEBUG
+	if (swpagerdebug & SDB_ALLOC)
+		printf("swpg_alloc: pg_data %x, %x of %x at %x\n",
+		       swp, swp->sw_nblocks, swp->sw_bsize, swp->sw_blocks);
+#endif
+	return(pager);
+}
+
+static void
+swap_pager_dealloc(pager)
+	vm_pager_t pager;
+{
+	register int i;
+	register sw_blk_t bp;
+	register sw_pager_t swp;
+	struct swtab *swt;
+	int s;
+
+#ifdef DEBUG
+	/* save panic time state */
+	if ((swpagerdebug & SDB_ANOMPANIC) && panicstr)
+		return;
+	if (swpagerdebug & (SDB_FOLLOW|SDB_ALLOC))
+		printf("swpg_dealloc(%x)\n", pager);
+#endif
+	/*
+	 * Remove from list right away so lookups will fail if we
+	 * block for pageout completion.
+	 */
+	swp = (sw_pager_t) pager->pg_data;
+	if (swp->sw_flags & SW_NAMED) {
+		TAILQ_REMOVE(&swap_pager_list, pager, pg_list);
+		swp->sw_flags &= ~SW_NAMED;
+	}
+#ifdef DEBUG
+	for (swt = swtab; swt->st_osize; swt++)
+		if (swp->sw_osize <= swt->st_osize)
+			break;
+	swt->st_inuse--;
+#endif
+
+	/*
+	 * Wait for all pageouts to finish and remove
+	 * all entries from cleaning list.
+	 */
+	s = splbio();
+	while (swp->sw_poip) {
+		swp->sw_flags |= SW_WANTED;
+		(void) tsleep(swp, PVM, "swpgdealloc", 0);
+	}
+	splx(s);
+	swap_pager_clean(B_WRITE);
+
+	/*
+	 * Free left over swap blocks
+	 */
+	for (i = 0, bp = swp->sw_blocks; i < swp->sw_nblocks; i++, bp++)
+		if (bp->swb_block) {
+#ifdef DEBUG
+			if (swpagerdebug & (SDB_ALLOCBLK|SDB_FULL))
+				printf("swpg_dealloc: blk %x\n",
+				       bp->swb_block);
+#endif
+			rmfree(swapmap, swp->sw_bsize, bp->swb_block);
+		}
+	/*
+	 * Free swap management resources
+	 */
+	free((caddr_t)swp->sw_blocks, M_VMPGDATA);
+	free((caddr_t)swp, M_VMPGDATA);
+	free((caddr_t)pager, M_VMPAGER);
+}
+
+static int
+swap_pager_getpage(pager, mlist, npages, sync)
+	vm_pager_t pager;
+	vm_page_t *mlist;
+	int npages;
+	boolean_t sync;
+{
+#ifdef DEBUG
+	if (swpagerdebug & SDB_FOLLOW)
+		printf("swpg_getpage(%x, %x, %x, %x)\n",
+		       pager, mlist, npages, sync);
+#endif
+	return(swap_pager_io((sw_pager_t)pager->pg_data,
+			     mlist, npages, B_READ));
+}
+
+static int
+swap_pager_putpage(pager, mlist, npages, sync)
+	vm_pager_t pager;
+	vm_page_t *mlist;
+	int npages;
+	boolean_t sync;
+{
+	int flags;
+
+#ifdef DEBUG
+	if (swpagerdebug & SDB_FOLLOW)
+		printf("swpg_putpage(%x, %x, %x, %x)\n",
+		       pager, mlist, npages, sync);
+#endif
+	if (pager == NULL) {
+		swap_pager_clean(B_WRITE);
+		return (VM_PAGER_OK);		/* ??? */
+	}
+	flags = B_WRITE;
+	if (!sync)
+		flags |= B_ASYNC;
+	return(swap_pager_io((sw_pager_t)pager->pg_data,
+			     mlist, npages, flags));
+}
+
+static boolean_t
+swap_pager_haspage(pager, offset)
+	vm_pager_t pager;
+	vm_offset_t offset;
+{
+	register sw_pager_t swp;
+	register sw_blk_t swb;
+	int ix;
+
+#ifdef DEBUG
+	if (swpagerdebug & (SDB_FOLLOW|SDB_ALLOCBLK))
+		printf("swpg_haspage(%x, %x) ", pager, offset);
+#endif
+	swp = (sw_pager_t) pager->pg_data;
+	ix = offset / dbtob(swp->sw_bsize);
+	if (swp->sw_blocks == NULL || ix >= swp->sw_nblocks) {
+#ifdef DEBUG
+		if (swpagerdebug & (SDB_FAIL|SDB_FOLLOW|SDB_ALLOCBLK))
+			printf("swpg_haspage: %x bad offset %x, ix %x\n",
+			       swp->sw_blocks, offset, ix);
+#endif
+		return(FALSE);
+	}
+	swb = &swp->sw_blocks[ix];
+	if (swb->swb_block)
+		ix = atop(offset % dbtob(swp->sw_bsize));
+#ifdef DEBUG
+	if (swpagerdebug & SDB_ALLOCBLK)
+		printf("%x blk %x+%x ", swp->sw_blocks, swb->swb_block, ix);
+	if (swpagerdebug & (SDB_FOLLOW|SDB_ALLOCBLK))
+		printf("-> %c\n",
+		       "FT"[swb->swb_block && (swb->swb_mask & (1 << ix))]);
+#endif
+	if (swb->swb_block && (swb->swb_mask & (1 << ix)))
+		return(TRUE);
+	return(FALSE);
+}
+
+static void
+swap_pager_cluster(pager, offset, loffset, hoffset)
+	vm_pager_t	pager;
+	vm_offset_t	offset;
+	vm_offset_t	*loffset;
+	vm_offset_t	*hoffset;
+{
+	sw_pager_t swp;
+	register int bsize;
+	vm_offset_t loff, hoff;
+
+#ifdef DEBUG
+	if (swpagerdebug & (SDB_FOLLOW|SDB_CLUSTER))
+		printf("swpg_cluster(%x, %x) ", pager, offset);
+#endif
+	swp = (sw_pager_t) pager->pg_data;
+	bsize = dbtob(swp->sw_bsize);
+	if (bsize > swap_pager_maxcluster)
+		bsize = swap_pager_maxcluster;
+
+	loff = offset - (offset % bsize);
+	if (loff >= swp->sw_osize)
+		panic("swap_pager_cluster: bad offset");
+
+	hoff = loff + bsize;
+	if (hoff > swp->sw_osize)
+		hoff = swp->sw_osize;
+
+	*loffset = loff;
+	*hoffset = hoff;
+#ifdef DEBUG
+	if (swpagerdebug & (SDB_FOLLOW|SDB_CLUSTER))
+		printf("returns [%x-%x]\n", loff, hoff);
+#endif
+}
+
+/*
+ * Scaled down version of swap().
+ * Assumes that PAGE_SIZE < MAXPHYS; i.e. only one operation needed.
+ * BOGUS:  lower level IO routines expect a KVA so we have to map our
+ * provided physical page into the KVA to keep them happy.
+ */
+static int
+swap_pager_io(swp, mlist, npages, flags)
+	register sw_pager_t swp;
+	vm_page_t *mlist;
+	int npages;
+	int flags;
+{
+	register struct buf *bp;
+	register sw_blk_t swb;
+	register int s;
+	int ix, mask;
+	boolean_t rv;
+	vm_offset_t kva, off;
+	swp_clean_t spc;
+	vm_page_t m;
+
+#ifdef DEBUG
+	/* save panic time state */
+	if ((swpagerdebug & SDB_ANOMPANIC) && panicstr)
+		return (VM_PAGER_FAIL);		/* XXX: correct return? */
+	if (swpagerdebug & (SDB_FOLLOW|SDB_IO))
+		printf("swpg_io(%x, %x, %x, %x)\n", swp, mlist, npages, flags);
+	if (flags & B_READ) {
+		if (flags & B_ASYNC)
+			panic("swap_pager_io: cannot do ASYNC reads");
+		if (npages != 1)
+			panic("swap_pager_io: cannot do clustered reads");
+	}
+#endif
+
+	/*
+	 * First determine if the page exists in the pager if this is
+	 * a sync read.  This quickly handles cases where we are
+	 * following shadow chains looking for the top level object
+	 * with the page.
+	 */
+	m = *mlist;
+	off = m->offset + m->object->paging_offset;
+	ix = off / dbtob(swp->sw_bsize);
+	if (swp->sw_blocks == NULL || ix >= swp->sw_nblocks) {
+#ifdef DEBUG
+		if ((flags & B_READ) == 0 && (swpagerdebug & SDB_ANOM)) {
+			printf("swap_pager_io: no swap block on write\n");
+			return(VM_PAGER_BAD);
+		}
+#endif
+		return(VM_PAGER_FAIL);
+	}
+	swb = &swp->sw_blocks[ix];
+	off = off % dbtob(swp->sw_bsize);
+	if ((flags & B_READ) &&
+	    (swb->swb_block == 0 || (swb->swb_mask & (1 << atop(off))) == 0))
+		return(VM_PAGER_FAIL);
+
+	/*
+	 * For reads (pageins) and synchronous writes, we clean up
+	 * all completed async pageouts.
+	 */
+	if ((flags & B_ASYNC) == 0) {
+		s = splbio();
+		swap_pager_clean(flags&B_READ);
+#ifdef DEBUG
+		if (swpagerdebug & SDB_PARANOIA)
+			swap_pager_clean_check(mlist, npages, flags&B_READ);
+#endif
+		splx(s);
+	}
+	/*
+	 * For async writes (pageouts), we cleanup completed pageouts so
+	 * that all available resources are freed.  Also tells us if this
+	 * page is already being cleaned.  If it is, or no resources
+	 * are available, we try again later.
+	 */
+	else {
+		swap_pager_clean(B_WRITE);
+#ifdef DEBUG
+		if (swpagerdebug & SDB_PARANOIA)
+			swap_pager_clean_check(mlist, npages, B_WRITE);
+#endif
+		if (swap_pager_free.tqh_first == NULL) {
+#ifdef DEBUG
+			if (swpagerdebug & SDB_FAIL)
+				printf("%s: no available io headers\n",
+				       "swap_pager_io");
+#endif
+			return(VM_PAGER_AGAIN);
+		}
+	}
+
+	/*
+	 * Allocate a swap block if necessary.
+	 */
+	if (swb->swb_block == 0) {
+		swb->swb_block = rmalloc(swapmap, swp->sw_bsize);
+		if (swb->swb_block == 0) {
+#ifdef DEBUG
+			if (swpagerdebug & SDB_FAIL)
+				printf("swpg_io: rmalloc of %x failed\n",
+				       swp->sw_bsize);
+#endif
+			/*
+			 * XXX this is technically a resource shortage that
+			 * should return AGAIN, but the situation isn't likely
+			 * to be remedied just by delaying a little while and
+			 * trying again (the pageout daemon's current response
+			 * to AGAIN) so we just return FAIL.
+			 */
+			return(VM_PAGER_FAIL);
+		}
+#ifdef DEBUG
+		if (swpagerdebug & (SDB_FULL|SDB_ALLOCBLK))
+			printf("swpg_io: %x alloc blk %x at ix %x\n",
+			       swp->sw_blocks, swb->swb_block, ix);
+#endif
+	}
+
+	/*
+	 * Allocate a kernel virtual address and initialize so that PTE
+	 * is available for lower level IO drivers.
+	 */
+	kva = vm_pager_map_pages(mlist, npages, !(flags & B_ASYNC));
+	if (kva == NULL) {
+#ifdef DEBUG
+		if (swpagerdebug & SDB_FAIL)
+			printf("%s: no KVA space to map pages\n",
+			       "swap_pager_io");
+#endif
+		return(VM_PAGER_AGAIN);
+	}
+
+	/*
+	 * Get a swap buffer header and initialize it.
+	 */
+	s = splbio();
+	while (bswlist.b_actf == NULL) {
+#ifdef DEBUG
+		if (swpagerdebug & SDB_ANOM)
+			printf("swap_pager_io: wait on swbuf for %x (%d)\n",
+			       m, flags);
+#endif
+		bswlist.b_flags |= B_WANTED;
+		tsleep((caddr_t)&bswlist, PSWP+1, "swpgiobuf", 0);
+	}
+	bp = bswlist.b_actf;
+	bswlist.b_actf = bp->b_actf;
+	splx(s);
+	bp->b_flags = B_BUSY | (flags & B_READ);
+	bp->b_proc = &proc0;	/* XXX (but without B_PHYS set this is ok) */
+	bp->b_data = (caddr_t)kva;
+	bp->b_blkno = swb->swb_block + btodb(off);
+	VHOLD(swapdev_vp);
+	bp->b_vp = swapdev_vp;
+	if (swapdev_vp->v_type == VBLK)
+		bp->b_dev = swapdev_vp->v_rdev;
+	bp->b_bcount = npages * PAGE_SIZE;
+
+	/*
+	 * For writes we set up additional buffer fields, record a pageout
+	 * in progress and mark that these swap blocks are now allocated.
+	 */
+	if ((bp->b_flags & B_READ) == 0) {
+		bp->b_dirtyoff = 0;
+		bp->b_dirtyend = npages * PAGE_SIZE;
+		swapdev_vp->v_numoutput++;
+		s = splbio();
+		swp->sw_poip++;
+		splx(s);
+		mask = (~(~0 << npages)) << atop(off);
+#ifdef DEBUG
+		swap_pager_poip++;
+		if (swpagerdebug & SDB_WRITE)
+			printf("swpg_io: write: bp=%x swp=%x poip=%d\n",
+			       bp, swp, swp->sw_poip);
+		if ((swpagerdebug & SDB_ALLOCBLK) &&
+		    (swb->swb_mask & mask) != mask)
+			printf("swpg_io: %x write %d pages at %x+%x\n",
+			       swp->sw_blocks, npages, swb->swb_block,
+			       atop(off));
+		if (swpagerdebug & SDB_CLUSTER)
+			printf("swpg_io: off=%x, npg=%x, mask=%x, bmask=%x\n",
+			       off, npages, mask, swb->swb_mask);
+#endif
+		swb->swb_mask |= mask;
+	}
+	/*
+	 * If this is an async write we set up still more buffer fields
+	 * and place a "cleaning" entry on the inuse queue.
+	 */
+	if ((flags & (B_READ|B_ASYNC)) == B_ASYNC) {
+#ifdef DEBUG
+		if (swap_pager_free.tqh_first == NULL)
+			panic("swpg_io: lost spc");
+#endif
+		spc = swap_pager_free.tqh_first;
+		TAILQ_REMOVE(&swap_pager_free, spc, spc_list);
+#ifdef DEBUG
+		if (spc->spc_flags != SPC_FREE)
+			panic("swpg_io: bad free spc");
+#endif
+		spc->spc_flags = SPC_BUSY;
+		spc->spc_bp = bp;
+		spc->spc_swp = swp;
+		spc->spc_kva = kva;
+		/*
+		 * Record the first page.  This allows swap_pager_clean
+		 * to efficiently handle the common case of a single page.
+		 * For clusters, it allows us to locate the object easily
+		 * and we then reconstruct the rest of the mlist from spc_kva.
+		 */
+		spc->spc_m = m;
+		spc->spc_npages = npages;
+		bp->b_flags |= B_CALL;
+		bp->b_iodone = swap_pager_iodone;
+		s = splbio();
+		TAILQ_INSERT_TAIL(&swap_pager_inuse, spc, spc_list);
+		splx(s);
+	}
+
+	/*
+	 * Finally, start the IO operation.
+	 * If it is async we are all done, otherwise we must wait for
+	 * completion and cleanup afterwards.
+	 */
+#ifdef DEBUG
+	if (swpagerdebug & SDB_IO)
+		printf("swpg_io: IO start: bp %x, db %x, va %x, pa %x\n",
+		       bp, swb->swb_block+btodb(off), kva, VM_PAGE_TO_PHYS(m));
+#endif
+	VOP_STRATEGY(bp);
+	if ((flags & (B_READ|B_ASYNC)) == B_ASYNC) {
+#ifdef DEBUG
+		if (swpagerdebug & SDB_IO)
+			printf("swpg_io:  IO started: bp %x\n", bp);
+#endif
+		return(VM_PAGER_PEND);
+	}
+	s = splbio();
+#ifdef DEBUG
+	if (flags & B_READ)
+		swap_pager_piip++;
+	else
+		swap_pager_poip++;
+#endif
+	while ((bp->b_flags & B_DONE) == 0)
+		(void) tsleep(bp, PVM, "swpgio", 0);
+	if ((flags & B_READ) == 0)
+		--swp->sw_poip;
+#ifdef DEBUG
+	if (flags & B_READ)
+		--swap_pager_piip;
+	else
+		--swap_pager_poip;
+#endif
+	rv = (bp->b_flags & B_ERROR) ? VM_PAGER_ERROR : VM_PAGER_OK;
+	bp->b_flags &= ~(B_BUSY|B_WANTED|B_PHYS|B_PAGET|B_UAREA|B_DIRTY);
+	bp->b_actf = bswlist.b_actf;
+	bswlist.b_actf = bp;
+	if (bp->b_vp)
+		brelvp(bp);
+	if (bswlist.b_flags & B_WANTED) {
+		bswlist.b_flags &= ~B_WANTED;
+		wakeup(&bswlist);
+	}
+	if ((flags & B_READ) == 0 && rv == VM_PAGER_OK) {
+		m->flags |= PG_CLEAN;
+		pmap_clear_modify(VM_PAGE_TO_PHYS(m));
+	}
+	splx(s);
+#ifdef DEBUG
+	if (swpagerdebug & SDB_IO)
+		printf("swpg_io:  IO done: bp %x, rv %d\n", bp, rv);
+	if ((swpagerdebug & SDB_FAIL) && rv == VM_PAGER_ERROR)
+		printf("swpg_io: IO error\n");
+#endif
+	vm_pager_unmap_pages(kva, npages);
+	return(rv);
+}
+
+static void
+swap_pager_clean(rw)
+	int rw;
+{
+	register swp_clean_t spc;
+	register int s, i;
+	vm_object_t object;
+	vm_page_t m;
+
+#ifdef DEBUG
+	/* save panic time state */
+	if ((swpagerdebug & SDB_ANOMPANIC) && panicstr)
+		return;
+	if (swpagerdebug & SDB_FOLLOW)
+		printf("swpg_clean(%x)\n", rw);
+#endif
+
+	for (;;) {
+		/*
+		 * Look up and removal from inuse list must be done
+		 * at splbio() to avoid conflicts with swap_pager_iodone.
+		 */
+		s = splbio();
+		for (spc = swap_pager_inuse.tqh_first;
+		     spc != NULL;
+		     spc = spc->spc_list.tqe_next) {
+			/*
+			 * If the operation is done, remove it from the
+			 * list and process it.
+			 *
+			 * XXX if we can't get the object lock we also
+			 * leave it on the list and try again later.
+			 * Is there something better we could do?
+			 */
+			if ((spc->spc_flags & SPC_DONE) &&
+			    vm_object_lock_try(spc->spc_m->object)) {
+				TAILQ_REMOVE(&swap_pager_inuse, spc, spc_list);
+				break;
+			}
+		}
+		splx(s);
+
+		/*
+		 * No operations done, thats all we can do for now.
+		 */
+		if (spc == NULL)
+			break;
+
+		/*
+		 * Found a completed operation so finish it off.
+		 * Note: no longer at splbio since entry is off the list.
+		 */
+		m = spc->spc_m;
+		object = m->object;
+
+		/*
+		 * Process each page in the cluster.
+		 * The first page is explicitly kept in the cleaning
+		 * entry, others must be reconstructed from the KVA.
+		 */
+		for (i = 0; i < spc->spc_npages; i++) {
+			if (i)
+				m = vm_pager_atop(spc->spc_kva + ptoa(i));
+			/*
+			 * If no error mark as clean and inform the pmap
+			 * system.  If there was an error, mark as dirty
+			 * so we will try again.
+			 *
+			 * XXX could get stuck doing this, should give up
+			 * after awhile.
+			 */
+			if (spc->spc_flags & SPC_ERROR) {
+				printf("%s: clean of page %x failed\n",
+				       "swap_pager_clean",
+				       VM_PAGE_TO_PHYS(m));
+				m->flags |= PG_LAUNDRY;
+			} else {
+				m->flags |= PG_CLEAN;
+				pmap_clear_modify(VM_PAGE_TO_PHYS(m));
+			}
+			m->flags &= ~PG_BUSY;
+			PAGE_WAKEUP(m);
+		}
+
+		/*
+		 * Done with the object, decrement the paging count
+		 * and unlock it.
+		 */
+		if (--object->paging_in_progress == 0)
+			wakeup(object);
+		vm_object_unlock(object);
+
+		/*
+		 * Free up KVM used and put the entry back on the list.
+		 */
+		vm_pager_unmap_pages(spc->spc_kva, spc->spc_npages);
+		spc->spc_flags = SPC_FREE;
+		TAILQ_INSERT_TAIL(&swap_pager_free, spc, spc_list);
+#ifdef DEBUG
+		if (swpagerdebug & SDB_WRITE)
+			printf("swpg_clean: free spc %x\n", spc);
+#endif
+	}
+}
+
+#ifdef DEBUG
+static void
+swap_pager_clean_check(mlist, npages, rw)
+	vm_page_t *mlist;
+	int npages;
+	int rw;
+{
+	register swp_clean_t spc;
+	boolean_t bad;
+	int i, j, s;
+	vm_page_t m;
+
+	if (panicstr)
+		return;
+
+	bad = FALSE;
+	s = splbio();
+	for (spc = swap_pager_inuse.tqh_first;
+	     spc != NULL;
+	     spc = spc->spc_list.tqe_next) {
+		for (j = 0; j < spc->spc_npages; j++) {
+			m = vm_pager_atop(spc->spc_kva + ptoa(j));
+			for (i = 0; i < npages; i++)
+				if (m == mlist[i]) {
+					if (swpagerdebug & SDB_ANOM)
+						printf(
+		"swpg_clean_check: %s: page %x on list, flags %x\n",
+		rw == B_WRITE ? "write" : "read", mlist[i], spc->spc_flags);
+					bad = TRUE;
+				}
+		}
+	}
+	splx(s);
+	if (bad)
+		panic("swpg_clean_check");
+}
+#endif
+
+static void
+swap_pager_iodone(bp)
+	register struct buf *bp;
+{
+	register swp_clean_t spc;
+	daddr_t blk;
+	int s;
+
+#ifdef DEBUG
+	/* save panic time state */
+	if ((swpagerdebug & SDB_ANOMPANIC) && panicstr)
+		return;
+	if (swpagerdebug & SDB_FOLLOW)
+		printf("swpg_iodone(%x)\n", bp);
+#endif
+	s = splbio();
+	for (spc = swap_pager_inuse.tqh_first;
+	     spc != NULL;
+	     spc = spc->spc_list.tqe_next)
+		if (spc->spc_bp == bp)
+			break;
+#ifdef DEBUG
+	if (spc == NULL)
+		panic("swap_pager_iodone: bp not found");
+#endif
+
+	spc->spc_flags &= ~SPC_BUSY;
+	spc->spc_flags |= SPC_DONE;
+	if (bp->b_flags & B_ERROR)
+		spc->spc_flags |= SPC_ERROR;
+	spc->spc_bp = NULL;
+	blk = bp->b_blkno;
+
+#ifdef DEBUG
+	--swap_pager_poip;
+	if (swpagerdebug & SDB_WRITE)
+		printf("swpg_iodone: bp=%x swp=%x flags=%x spc=%x poip=%x\n",
+		       bp, spc->spc_swp, spc->spc_swp->sw_flags,
+		       spc, spc->spc_swp->sw_poip);
+#endif
+
+	spc->spc_swp->sw_poip--;
+	if (spc->spc_swp->sw_flags & SW_WANTED) {
+		spc->spc_swp->sw_flags &= ~SW_WANTED;
+		wakeup(spc->spc_swp);
+	}
+		
+	bp->b_flags &= ~(B_BUSY|B_WANTED|B_PHYS|B_PAGET|B_UAREA|B_DIRTY);
+	bp->b_actf = bswlist.b_actf;
+	bswlist.b_actf = bp;
+	if (bp->b_vp)
+		brelvp(bp);
+	if (bswlist.b_flags & B_WANTED) {
+		bswlist.b_flags &= ~B_WANTED;
+		wakeup(&bswlist);
+	}
+	wakeup(&vm_pages_needed);
+	splx(s);
+}
diff --git a/sys/vm/swap_pager.h b/sys/vm/swap_pager.h
new file mode 100644
index 0000000..497d92a
--- /dev/null
+++ b/sys/vm/swap_pager.h
@@ -0,0 +1,90 @@
+/*
+ * Copyright (c) 1990 University of Utah.
+ * Copyright (c) 1991, 1993
+ *	The Regents of the University of California.  All rights reserved.
+ *
+ * This code is derived from software contributed to Berkeley by
+ * the Systems Programming Group of the University of Utah Computer
+ * Science Department.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. All advertising materials mentioning features or use of this software
+ *    must display the following acknowledgement:
+ *	This product includes software developed by the University of
+ *	California, Berkeley and its contributors.
+ * 4. Neither the name of the University nor the names of its contributors
+ *    may be used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ *
+ *	@(#)swap_pager.h	8.1 (Berkeley) 6/11/93
+ */
+
+#ifndef	_SWAP_PAGER_
+#define	_SWAP_PAGER_	1
+
+/*
+ * In the swap pager, the backing store for an object is organized as an
+ * array of some number of "swap blocks".  A swap block consists of a bitmask
+ * and some number of contiguous DEV_BSIZE disk blocks.  The minimum size
+ * of a swap block is:
+ *
+ *	max(PAGE_SIZE, dmmin*DEV_BSIZE)			[ 32k currently ]
+ *
+ * bytes (since the pager interface is page oriented), the maximum size is:
+ *
+ *	min(#bits(swb_mask)*PAGE_SIZE, dmmax*DEV_BSIZE)	[ 128k currently ]
+ *
+ * where dmmin and dmmax are left over from the old VM interface.  The bitmask
+ * (swb_mask) is used by swap_pager_haspage() to determine if a particular
+ * page has actually been written; i.e. the pager copy of the page is valid.
+ * All swap blocks in the backing store of an object will be the same size.
+ *
+ * The reason for variable sized swap blocks is to reduce fragmentation of
+ * swap resources.  Whenever possible we allocate smaller swap blocks to
+ * smaller objects.  The swap block size is determined from a table of
+ * object-size vs. swap-block-size computed at boot time.
+ */
+typedef	int	sw_bm_t;	/* pager bitmask */
+
+struct	swblock {
+	sw_bm_t	 swb_mask;	/* bitmask of valid pages in this block */
+	daddr_t	 swb_block;	/* starting disk block for this block */
+};
+typedef struct swblock	*sw_blk_t;
+
+/*
+ * Swap pager private data.
+ */
+struct swpager {
+	vm_size_t    sw_osize;	/* size of object we are backing (bytes) */
+	int	     sw_bsize;	/* size of swap blocks (DEV_BSIZE units) */
+	int	     sw_nblocks;/* number of blocks in list (sw_blk_t units) */
+	sw_blk_t     sw_blocks;	/* pointer to list of swap blocks */
+	short	     sw_flags;	/* flags */
+	short	     sw_poip;	/* pageouts in progress */
+};
+typedef struct swpager	*sw_pager_t;
+
+#define	SW_WANTED	0x01
+#define SW_NAMED	0x02
+
+#endif	/* _SWAP_PAGER_ */
diff --git a/sys/vm/vm.h b/sys/vm/vm.h
new file mode 100644
index 0000000..85f892f
--- /dev/null
+++ b/sys/vm/vm.h
@@ -0,0 +1,91 @@
+/*
+ * Copyright (c) 1991, 1993
+ *	The Regents of the University of California.  All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. All advertising materials mentioning features or use of this software
+ *    must display the following acknowledgement:
+ *	This product includes software developed by the University of
+ *	California, Berkeley and its contributors.
+ * 4. Neither the name of the University nor the names of its contributors
+ *    may be used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ *
+ *	@(#)vm.h	8.2 (Berkeley) 12/13/93
+ */
+
+#ifndef VM_H
+#define VM_H
+
+typedef int vm_inherit_t;		/* XXX: inheritance codes */
+
+union vm_map_object;
+typedef union vm_map_object vm_map_object_t;
+
+struct vm_map_entry;
+typedef struct vm_map_entry *vm_map_entry_t;
+
+struct vm_map;
+typedef struct vm_map *vm_map_t;
+
+struct vm_object;
+typedef struct vm_object *vm_object_t;
+
+struct vm_page;
+typedef struct vm_page  *vm_page_t;
+
+struct pager_struct;
+typedef struct pager_struct *vm_pager_t;
+
+#include <sys/vmmeter.h>
+#include <sys/queue.h>
+#include <vm/vm_param.h>
+#include <vm/lock.h>
+#include <vm/vm_prot.h>
+#include <vm/vm_inherit.h>
+#include <vm/vm_map.h>
+#include <vm/vm_object.h>
+#include <vm/pmap.h>
+#include <vm/vm_extern.h>
+
+/*
+ * Shareable process virtual address space.
+ * May eventually be merged with vm_map.
+ * Several fields are temporary (text, data stuff).
+ */
+struct vmspace {
+	struct	vm_map vm_map;	/* VM address map */
+	struct	pmap vm_pmap;	/* private physical map */
+	int	vm_refcnt;	/* number of references */
+	caddr_t	vm_shm;		/* SYS5 shared memory private data XXX */
+/* we copy from vm_startcopy to the end of the structure on fork */
+#define vm_startcopy vm_rssize
+	segsz_t vm_rssize; 	/* current resident set size in pages */
+	segsz_t vm_swrss;	/* resident set size before last swap */
+	segsz_t vm_tsize;	/* text size (pages) XXX */
+	segsz_t vm_dsize;	/* data size (pages) XXX */
+	segsz_t vm_ssize;	/* stack size (pages) */
+	caddr_t	vm_taddr;	/* user virtual address of text XXX */
+	caddr_t	vm_daddr;	/* user virtual address of data XXX */
+	caddr_t vm_maxsaddr;	/* user VA at max stack growth */
+};
+#endif /* VM_H */
diff --git a/sys/vm/vm_extern.h b/sys/vm/vm_extern.h
new file mode 100644
index 0000000..bae5f00
--- /dev/null
+++ b/sys/vm/vm_extern.h
@@ -0,0 +1,125 @@
+/*-
+ * Copyright (c) 1992, 1993
+ *	The Regents of the University of California.  All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. All advertising materials mentioning features or use of this software
+ *    must display the following acknowledgement:
+ *	This product includes software developed by the University of
+ *	California, Berkeley and its contributors.
+ * 4. Neither the name of the University nor the names of its contributors
+ *    may be used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ *
+ *	@(#)vm_extern.h	8.2 (Berkeley) 1/12/94
+ */
+
+struct buf;
+struct loadavg;
+struct proc;
+struct vmspace;
+struct vmtotal;
+struct mount;
+struct vnode;
+
+#ifdef KGDB
+void		 chgkprot __P((caddr_t, int, int));
+#endif
+
+#ifdef KERNEL
+#ifdef TYPEDEF_FOR_UAP
+int		 getpagesize __P((struct proc *p, void *, int *));
+int		 madvise __P((struct proc *, void *, int *));
+int		 mincore __P((struct proc *, void *, int *));
+int		 mprotect __P((struct proc *, void *, int *));
+int		 msync __P((struct proc *, void *, int *));
+int		 munmap __P((struct proc *, void *, int *));
+int		 obreak __P((struct proc *, void *, int *));
+int		 sbrk __P((struct proc *, void *, int *));
+int		 smmap __P((struct proc *, void *, int *));
+int		 sstk __P((struct proc *, void *, int *));
+#endif
+
+void		 assert_wait __P((int, boolean_t));
+int		 grow __P((struct proc *, u_int));
+void		 iprintf __P((const char *, ...));
+int		 kernacc __P((caddr_t, int, int));
+int		 kinfo_loadavg __P((int, char *, int *, int, int *));
+int		 kinfo_meter __P((int, caddr_t, int *, int, int *));
+vm_offset_t	 kmem_alloc __P((vm_map_t, vm_size_t));
+vm_offset_t	 kmem_alloc_pageable __P((vm_map_t, vm_size_t));
+vm_offset_t	 kmem_alloc_wait __P((vm_map_t, vm_size_t));
+void		 kmem_free __P((vm_map_t, vm_offset_t, vm_size_t));
+void		 kmem_free_wakeup __P((vm_map_t, vm_offset_t, vm_size_t));
+void		 kmem_init __P((vm_offset_t, vm_offset_t));
+vm_offset_t	 kmem_malloc __P((vm_map_t, vm_size_t, boolean_t));
+vm_map_t	 kmem_suballoc __P((vm_map_t, vm_offset_t *, vm_offset_t *,
+		    vm_size_t, boolean_t));
+void		 loadav __P((struct loadavg *));
+void		 munmapfd __P((int));
+int		 pager_cache __P((vm_object_t, boolean_t));
+void		 sched __P((void));
+int		 svm_allocate __P((struct proc *, void *, int *));
+int		 svm_deallocate __P((struct proc *, void *, int *));
+int		 svm_inherit __P((struct proc *, void *, int *));
+int		 svm_protect __P((struct proc *, void *, int *));
+void		 swapinit __P((void));
+int		 swapon __P((struct proc *, void *, int *));
+void		 swapout __P((struct proc *));
+void		 swapout_threads __P((void));
+int		 swfree __P((struct proc *, int));
+void		 swstrategy __P((struct buf *));
+void		 thread_block __P((void));
+void		 thread_sleep __P((int, simple_lock_t, boolean_t));
+void		 thread_wakeup __P((int));
+int		 useracc __P((caddr_t, int, int));
+int		 vm_allocate __P((vm_map_t,
+		    vm_offset_t *, vm_size_t, boolean_t));
+int		 vm_allocate_with_pager __P((vm_map_t, vm_offset_t *,
+		    vm_size_t, boolean_t, vm_pager_t, vm_offset_t, boolean_t));
+int		 vm_deallocate __P((vm_map_t, vm_offset_t, vm_size_t));
+int		 vm_fault __P((vm_map_t, vm_offset_t, vm_prot_t, boolean_t));
+void		 vm_fault_copy_entry __P((vm_map_t,
+		    vm_map_t, vm_map_entry_t, vm_map_entry_t));
+void		 vm_fault_unwire __P((vm_map_t, vm_offset_t, vm_offset_t));
+int		 vm_fault_wire __P((vm_map_t, vm_offset_t, vm_offset_t));
+int		 vm_fork __P((struct proc *, struct proc *, int));
+int		 vm_inherit __P((vm_map_t,
+		    vm_offset_t, vm_size_t, vm_inherit_t));
+void		 vm_init_limits __P((struct proc *));
+void		 vm_mem_init __P((void));
+int		 vm_mmap __P((vm_map_t, vm_offset_t *, vm_size_t,
+		    vm_prot_t, vm_prot_t, int, caddr_t, vm_offset_t));
+int		 vm_protect __P((vm_map_t,
+		    vm_offset_t, vm_size_t, boolean_t, vm_prot_t));
+void		 vm_set_page_size __P((void));
+void		 vmmeter __P((void));
+struct vmspace	*vmspace_alloc __P((vm_offset_t, vm_offset_t, int));
+struct vmspace	*vmspace_fork __P((struct vmspace *));
+void		 vmspace_free __P((struct vmspace *));
+void		 vmtotal __P((struct vmtotal *));
+void		 vnode_pager_setsize __P((struct vnode *, u_long));
+void		 vnode_pager_umount __P((struct mount *));
+boolean_t	 vnode_pager_uncache __P((struct vnode *));
+void		 vslock __P((caddr_t, u_int));
+void		 vsunlock __P((caddr_t, u_int, int));
+#endif
diff --git a/sys/vm/vm_fault.c b/sys/vm/vm_fault.c
new file mode 100644
index 0000000..f60abf2
--- /dev/null
+++ b/sys/vm/vm_fault.c
@@ -0,0 +1,1035 @@
+/* 
+ * Copyright (c) 1991, 1993
+ *	The Regents of the University of California.  All rights reserved.
+ *
+ * This code is derived from software contributed to Berkeley by
+ * The Mach Operating System project at Carnegie-Mellon University.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. All advertising materials mentioning features or use of this software
+ *    must display the following acknowledgement:
+ *	This product includes software developed by the University of
+ *	California, Berkeley and its contributors.
+ * 4. Neither the name of the University nor the names of its contributors
+ *    may be used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ *
+ *	@(#)vm_fault.c	8.4 (Berkeley) 1/12/94
+ *
+ *
+ * Copyright (c) 1987, 1990 Carnegie-Mellon University.
+ * All rights reserved.
+ *
+ * Authors: Avadis Tevanian, Jr., Michael Wayne Young
+ * 
+ * Permission to use, copy, modify and distribute this software and
+ * its documentation is hereby granted, provided that both the copyright
+ * notice and this permission notice appear in all copies of the
+ * software, derivative works or modified versions, and any portions
+ * thereof, and that both notices appear in supporting documentation.
+ * 
+ * CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS" 
+ * CONDITION.  CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND 
+ * FOR ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
+ * 
+ * Carnegie Mellon requests users of this software to return to
+ *
+ *  Software Distribution Coordinator  or  Software.Distribution@CS.CMU.EDU
+ *  School of Computer Science
+ *  Carnegie Mellon University
+ *  Pittsburgh PA 15213-3890
+ *
+ * any improvements or extensions that they make and grant Carnegie the
+ * rights to redistribute these changes.
+ */
+
+/*
+ *	Page fault handling module.
+ */
+
+#include <sys/param.h>
+#include <sys/systm.h>
+
+#include <vm/vm.h>
+#include <vm/vm_page.h>
+#include <vm/vm_pageout.h>
+
+/*
+ *	vm_fault:
+ *
+ *	Handle a page fault occuring at the given address,
+ *	requiring the given permissions, in the map specified.
+ *	If successful, the page is inserted into the
+ *	associated physical map.
+ *
+ *	NOTE: the given address should be truncated to the
+ *	proper page address.
+ *
+ *	KERN_SUCCESS is returned if the page fault is handled; otherwise,
+ *	a standard error specifying why the fault is fatal is returned.
+ *
+ *
+ *	The map in question must be referenced, and remains so.
+ *	Caller may hold no locks.
+ */
+int
+vm_fault(map, vaddr, fault_type, change_wiring)
+	vm_map_t	map;
+	vm_offset_t	vaddr;
+	vm_prot_t	fault_type;
+	boolean_t	change_wiring;
+{
+	vm_object_t		first_object;
+	vm_offset_t		first_offset;
+	vm_map_entry_t		entry;
+	register vm_object_t	object;
+	register vm_offset_t	offset;
+	register vm_page_t	m;
+	vm_page_t		first_m;
+	vm_prot_t		prot;
+	int			result;
+	boolean_t		wired;
+	boolean_t		su;
+	boolean_t		lookup_still_valid;
+	boolean_t		page_exists;
+	vm_page_t		old_m;
+	vm_object_t		next_object;
+
+	cnt.v_faults++;		/* needs lock XXX */
+/*
+ *	Recovery actions
+ */
+#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();				\
+	vm_page_activate(m);				\
+	vm_page_unlock_queues();			\
+}
+
+#define	UNLOCK_MAP	{				\
+	if (lookup_still_valid) {			\
+		vm_map_lookup_done(map, entry);		\
+		lookup_still_valid = FALSE;		\
+	}						\
+}
+
+#define	UNLOCK_THINGS	{				\
+	object->paging_in_progress--;			\
+	vm_object_unlock(object);			\
+	if (object != first_object) {			\
+		vm_object_lock(first_object);		\
+		FREE_PAGE(first_m);			\
+		first_object->paging_in_progress--;	\
+		vm_object_unlock(first_object);		\
+	}						\
+	UNLOCK_MAP;					\
+}
+
+#define	UNLOCK_AND_DEALLOCATE	{			\
+	UNLOCK_THINGS;					\
+	vm_object_deallocate(first_object);		\
+}
+
+    RetryFault: ;
+
+	/*
+	 *	Find the backing store object and offset into
+	 *	it to begin the search.
+	 */
+
+	if ((result = vm_map_lookup(&map, vaddr, fault_type, &entry,
+			&first_object, &first_offset,
+			&prot, &wired, &su)) != KERN_SUCCESS) {
+		return(result);
+	}
+	lookup_still_valid = TRUE;
+
+	if (wired)
+		fault_type = prot;
+
+	first_m = NULL;
+
+   	/*
+	 *	Make a reference to this object to
+	 *	prevent its disposal while we are messing with
+	 *	it.  Once we have the reference, the map is free
+	 *	to be diddled.  Since objects reference their
+	 *	shadows (and copies), they will stay around as well.
+	 */
+
+	vm_object_lock(first_object);
+
+	first_object->ref_count++;
+	first_object->paging_in_progress++;
+
+	/*
+	 *	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 bring in
+	 *		the same page.
+	 *
+	 *		Note that we cannot hold any locks during the
+	 *		pager access or when waiting for memory, so
+	 *		we use a busy page then.
+	 *
+	 *		Note also that we aren't as concerned about
+	 *		more than one thead attempting to pager_data_unlock
+	 *		the same page at once, so we don't hold the page
+	 *		as busy then, but do record the highest unlock
+	 *		value so far.  [Unlock requests may also be delivered
+	 *		out of order.]
+	 *
+	 *	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 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.
+	 *
+	 *	4)	We must increment paging_in_progress on any object
+	 *		for which we have a busy page, to prevent
+	 *		vm_object_collapse from removing the busy page
+	 *		without our noticing.
+	 */
+
+	/*
+	 *	Search for the page at object/offset.
+	 */
+
+	object = first_object;
+	offset = first_offset;
+
+	/*
+	 *	See whether this page is resident
+	 */
+
+	while (TRUE) {
+		m = vm_page_lookup(object, offset);
+		if (m != NULL) {
+			/*
+			 *	If the page is being brought in,
+			 *	wait for it and then retry.
+			 */
+			if (m->flags & PG_BUSY) {
+#ifdef DOTHREADS
+				int	wait_result;
+
+				PAGE_ASSERT_WAIT(m, !change_wiring);
+				UNLOCK_THINGS;
+				thread_block();
+				wait_result = current_thread()->wait_result;
+				vm_object_deallocate(first_object);
+				if (wait_result != THREAD_AWAKENED)
+					return(KERN_SUCCESS);
+				goto RetryFault;
+#else
+				PAGE_ASSERT_WAIT(m, !change_wiring);
+				UNLOCK_THINGS;
+				cnt.v_intrans++;
+				thread_block();
+				vm_object_deallocate(first_object);
+				goto RetryFault;
+#endif
+			}
+
+			/*
+			 *	Remove the page from the pageout daemon's
+			 *	reach while we play with it.
+			 */
+
+			vm_page_lock_queues();
+			if (m->flags & PG_INACTIVE) {
+				TAILQ_REMOVE(&vm_page_queue_inactive, m, pageq);
+				m->flags &= ~PG_INACTIVE;
+				cnt.v_inactive_count--;
+				cnt.v_reactivated++;
+			} 
+
+			if (m->flags & PG_ACTIVE) {
+				TAILQ_REMOVE(&vm_page_queue_active, m, pageq);
+				m->flags &= ~PG_ACTIVE;
+				cnt.v_active_count--;
+			}
+			vm_page_unlock_queues();
+
+			/*
+			 *	Mark page busy for other threads.
+			 */
+			m->flags |= PG_BUSY;
+			break;
+		}
+
+		if (((object->pager != NULL) &&
+				(!change_wiring || wired))
+		    || (object == first_object)) {
+
+			/*
+			 *	Allocate a new page for this object/offset
+			 *	pair.
+			 */
+
+			m = vm_page_alloc(object, offset);
+
+			if (m == NULL) {
+				UNLOCK_AND_DEALLOCATE;
+				VM_WAIT;
+				goto RetryFault;
+			}
+		}
+
+		if (object->pager != NULL && (!change_wiring || wired)) {
+			int rv;
+
+			/*
+			 *	Now that we have a busy page, we can
+			 *	release the object lock.
+			 */
+			vm_object_unlock(object);
+
+			/*
+			 *	Call the pager to retrieve the data, if any,
+			 *	after releasing the lock on the map.
+			 */
+			UNLOCK_MAP;
+			cnt.v_pageins++;
+			rv = vm_pager_get(object->pager, m, TRUE);
+
+			/*
+			 *	Reaquire the object lock to preserve our
+			 *	invariant.
+			 */
+			vm_object_lock(object);
+
+			/*
+			 *	Found the page.
+			 *	Leave it busy while we play with it.
+			 */
+			if (rv == VM_PAGER_OK) {
+				/*
+				 *	Relookup in case pager changed page.
+				 *	Pager is responsible for disposition
+				 *	of old page if moved.
+				 */
+				m = vm_page_lookup(object, offset);
+
+				cnt.v_pgpgin++;
+				m->flags &= ~PG_FAKE;
+				m->flags |= PG_CLEAN;
+				pmap_clear_modify(VM_PAGE_TO_PHYS(m));
+				break;
+			}
+
+			/*
+			 * IO error or page outside the range of the pager:
+			 * cleanup and return an error.
+			 */
+			if (rv == VM_PAGER_ERROR || rv == VM_PAGER_BAD) {
+				FREE_PAGE(m);
+				UNLOCK_AND_DEALLOCATE;
+				return(KERN_PROTECTION_FAILURE); /* XXX */
+			}
+			/*
+			 * rv == VM_PAGER_FAIL:
+			 *
+			 * Page does not exist at this object/offset.
+			 * Free the bogus page (waking up anyone waiting
+			 * for it) and continue on to the next object.
+			 *
+			 * If this is the top-level object, we must
+			 * leave the busy page to prevent another
+			 * thread from rushing past us, and inserting
+			 * the page in that object at the same time
+			 * that we are.
+			 */
+			if (object != first_object) {
+				FREE_PAGE(m);
+				/* note that `m' is not used after this */
+			}
+		}
+
+		/*
+		 * We get here if the object has no pager (or unwiring)
+		 * or the pager doesn't have the page.
+		 */
+		if (object == first_object)
+			first_m = m;
+
+		/*
+		 *	Move on to the next object.  Lock the next
+		 *	object before unlocking the current one.
+		 */
+
+		offset += object->shadow_offset;
+		next_object = object->shadow;
+		if (next_object == NULL) {
+			/*
+			 *	If there's no object left, fill the page
+			 *	in the top object with zeros.
+			 */
+			if (object != first_object) {
+				object->paging_in_progress--;
+				vm_object_unlock(object);
+
+				object = first_object;
+				offset = first_offset;
+				m = first_m;
+				vm_object_lock(object);
+			}
+			first_m = NULL;
+
+			vm_page_zero_fill(m);
+			cnt.v_zfod++;
+			m->flags &= ~PG_FAKE;
+			break;
+		}
+		else {
+			vm_object_lock(next_object);
+			if (object != first_object)
+				object->paging_in_progress--;
+			vm_object_unlock(object);
+			object = next_object;
+			object->paging_in_progress++;
+		}
+	}
+
+	if ((m->flags & (PG_ACTIVE | PG_INACTIVE | PG_BUSY)) != PG_BUSY)
+		panic("vm_fault: active, inactive or !busy after main loop");
+
+	/*
+	 *	PAGE HAS BEEN FOUND.
+	 *	[Loop invariant still holds -- the object lock
+	 *	is held.]
+	 */
+
+	old_m = m;	/* save page that would be copied */
+
+	/*
+	 *	If the page is being written, but isn't
+	 *	already owned by the top-level object,
+	 *	we have to copy it into a new page owned
+	 *	by the top-level object.
+	 */
+
+	if (object != first_object) {
+	    	/*
+		 *	We only really need to copy if we
+		 *	want to write it.
+		 */
+
+	    	if (fault_type & VM_PROT_WRITE) {
+
+			/*
+			 *	If we try to collapse first_object at this
+			 *	point, we may deadlock when we try to get
+			 *	the lock on an intermediate object (since we
+			 *	have the bottom object locked).  We can't
+			 *	unlock the bottom object, because the page
+			 *	we found may move (by collapse) if we do.
+			 *
+			 *	Instead, we first copy the page.  Then, when
+			 *	we have no more use for the bottom object,
+			 *	we unlock it and try to collapse.
+			 *
+			 *	Note that we copy the page even if we didn't
+			 *	need to... that's the breaks.
+			 */
+
+		    	/*
+			 *	We already have an empty page in
+			 *	first_object - use it.
+			 */
+
+			vm_page_copy(m, first_m);
+			first_m->flags &= ~PG_FAKE;
+
+			/*
+			 *	If another map is truly sharing this
+			 *	page with us, we have to flush all
+			 *	uses of the original page, since we
+			 *	can't distinguish those which want the
+			 *	original from those which need the
+			 *	new copy.
+			 *
+			 *	XXX If we know that only one map has
+			 *	access to this page, then we could
+			 *	avoid the pmap_page_protect() call.
+			 */
+
+			vm_page_lock_queues();
+			vm_page_activate(m);
+			vm_page_deactivate(m);
+			pmap_page_protect(VM_PAGE_TO_PHYS(m), VM_PROT_NONE);
+			vm_page_unlock_queues();
+
+			/*
+			 *	We no longer need the old page or object.
+			 */
+			PAGE_WAKEUP(m);
+			object->paging_in_progress--;
+			vm_object_unlock(object);
+
+			/*
+			 *	Only use the new page below...
+			 */
+
+			cnt.v_cow_faults++;
+			m = first_m;
+			object = first_object;
+			offset = first_offset;
+
+			/*
+			 *	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...
+			 */
+			object->paging_in_progress--;
+			vm_object_collapse(object);
+			object->paging_in_progress++;
+		}
+		else {
+		    	prot &= ~VM_PROT_WRITE;
+			m->flags |= PG_COPYONWRITE;
+		}
+	}
+
+	if (m->flags & (PG_ACTIVE|PG_INACTIVE))
+		panic("vm_fault: active or inactive before copy object handling");
+
+	/*
+	 *	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);
+			if (page_exists = (copy_m != NULL)) {
+				if (copy_m->flags & PG_BUSY) {
+#ifdef DOTHREADS
+					int	wait_result;
+
+					/*
+					 *	If the page is being brought
+					 *	in, wait for it and then retry.
+					 */
+					PAGE_ASSERT_WAIT(copy_m, !change_wiring);
+					RELEASE_PAGE(m);
+					copy_object->ref_count--;
+					vm_object_unlock(copy_object);
+					UNLOCK_THINGS;
+					thread_block();
+					wait_result = current_thread()->wait_result;
+					vm_object_deallocate(first_object);
+					if (wait_result != THREAD_AWAKENED)
+						return(KERN_SUCCESS);
+					goto RetryFault;
+#else
+					/*
+					 *	If the page is being brought
+					 *	in, wait for it and then retry.
+					 */
+					PAGE_ASSERT_WAIT(copy_m, !change_wiring);
+					RELEASE_PAGE(m);
+					copy_object->ref_count--;
+					vm_object_unlock(copy_object);
+					UNLOCK_THINGS;
+					thread_block();
+					vm_object_deallocate(first_object);
+					goto RetryFault;
+#endif
+				}
+			}
+
+			/*
+			 *	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);
+				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->flags &= ~PG_FAKE;
+
+				/*
+				 * 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();
+				pmap_page_protect(VM_PAGE_TO_PHYS(old_m),
+						  VM_PROT_NONE);
+				copy_m->flags &= ~PG_CLEAN;
+				vm_page_activate(copy_m);	/* XXX */
+				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;
+		}
+	}
+
+	if (m->flags & (PG_ACTIVE | PG_INACTIVE))
+		panic("vm_fault: active or inactive before retrying lookup");
+
+	/*
+	 *	We must verify that the maps have not changed
+	 *	since our last lookup.
+	 */
+
+	if (!lookup_still_valid) {
+		vm_object_t	retry_object;
+		vm_offset_t	retry_offset;
+		vm_prot_t	retry_prot;
+
+		/*
+		 *	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 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 needs_copy, we enter the
+		 *	mapping without write permission, and will merely
+		 *	take another fault.
+		 */
+		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, pageout will grab it eventually.
+		 */
+
+		if (result != KERN_SUCCESS) {
+			RELEASE_PAGE(m);
+			UNLOCK_AND_DEALLOCATE;
+			return(result);
+		}
+
+		lookup_still_valid = TRUE;
+
+		if ((retry_object != first_object) ||
+				(retry_offset != first_offset)) {
+			RELEASE_PAGE(m);
+			UNLOCK_AND_DEALLOCATE;
+			goto RetryFault;
+		}
+
+		/*
+		 *	Check whether the protection has changed or the object
+		 *	has been copied while we left the map unlocked.
+		 *	Changing from read to write permission is OK - we leave
+		 *	the page write-protected, and catch the write fault.
+		 *	Changing from write to read permission means that we
+		 *	can't mark the page write-enabled after all.
+		 */
+		prot &= retry_prot;
+		if (m->flags & PG_COPYONWRITE)
+			prot &= ~VM_PROT_WRITE;
+	}
+
+	/*
+	 * (the various bits we're fiddling with here are locked by
+	 * the object's lock)
+	 */
+
+	/* XXX This distorts the meaning of the copy_on_write bit */
+
+	if (prot & VM_PROT_WRITE)
+		m->flags &= ~PG_COPYONWRITE;
+
+	/*
+	 *	It's critically important that a wired-down page be faulted
+	 *	only once in each map for which it is wired.
+	 */
+
+	if (m->flags & (PG_ACTIVE | PG_INACTIVE))
+		panic("vm_fault: active or inactive before pmap_enter");
+
+	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 back on the active queue until later so
+	 *	that the page-out daemon won't find us (yet).
+	 */
+
+	pmap_enter(map->pmap, vaddr, VM_PAGE_TO_PHYS(m), prot, wired);
+
+	/*
+	 *	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);
+		else
+			vm_page_unwire(m);
+	}
+	else
+		vm_page_activate(m);
+	vm_page_unlock_queues();
+
+	/*
+	 *	Unlock everything, and return
+	 */
+
+	PAGE_WAKEUP(m);
+	UNLOCK_AND_DEALLOCATE;
+
+	return(KERN_SUCCESS);
+
+}
+
+/*
+ *	vm_fault_wire:
+ *
+ *	Wire down a range of virtual addresses in a map.
+ */
+int
+vm_fault_wire(map, start, end)
+	vm_map_t	map;
+	vm_offset_t	start, end;
+{
+	register vm_offset_t	va;
+	register pmap_t		pmap;
+	int			rv;
+
+	pmap = vm_map_pmap(map);
+
+	/*
+	 *	Inform the physical mapping system that the
+	 *	range of addresses may not fault, so that
+	 *	page tables and such can be locked down as well.
+	 */
+
+	pmap_pageable(pmap, start, end, FALSE);
+
+	/*
+	 *	We simulate a fault to get the page and enter it
+	 *	in the physical map.
+	 */
+
+	for (va = start; va < end; va += PAGE_SIZE) {
+		rv = vm_fault(map, va, VM_PROT_NONE, TRUE);
+		if (rv) {
+			if (va != start)
+				vm_fault_unwire(map, start, va);
+			return(rv);
+		}
+	}
+	return(KERN_SUCCESS);
+}
+
+
+/*
+ *	vm_fault_unwire:
+ *
+ *	Unwire a range of virtual addresses in a map.
+ */
+void vm_fault_unwire(map, start, end)
+	vm_map_t	map;
+	vm_offset_t	start, end;
+{
+
+	register vm_offset_t	va, pa;
+	register pmap_t		pmap;
+
+	pmap = vm_map_pmap(map);
+
+	/*
+	 *	Since the pages are wired down, we must be able to
+	 *	get their 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) {
+			panic("unwire: page not in pmap");
+		}
+		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 fault, so that page tables and
+	 *	such may be unwired themselves.
+	 */
+
+	pmap_pageable(pmap, start, end, TRUE);
+
+}
+
+/*
+ *	Routine:
+ *		vm_fault_copy_entry
+ *	Function:
+ *		Copy all of the pages from a wired-down map entry to another.
+ *
+ *	In/out conditions:
+ *		The source and destination maps must be locked for write.
+ *		The source map entry must be wired down (or be a sharing map
+ *		entry corresponding to a main map entry that is wired down).
+ */
+
+void vm_fault_copy_entry(dst_map, src_map, dst_entry, src_entry)
+	vm_map_t	dst_map;
+	vm_map_t	src_map;
+	vm_map_entry_t	dst_entry;
+	vm_map_entry_t	src_entry;
+{
+
+	vm_object_t	dst_object;
+	vm_object_t	src_object;
+	vm_offset_t	dst_offset;
+	vm_offset_t	src_offset;
+	vm_prot_t	prot;
+	vm_offset_t	vaddr;
+	vm_page_t	dst_m;
+	vm_page_t	src_m;
+
+#ifdef	lint
+	src_map++;
+#endif
+
+	src_object = src_entry->object.vm_object;
+	src_offset = src_entry->offset;
+
+	/*
+	 *	Create the top-level object for the destination entry.
+	 *	(Doesn't actually shadow anything - we copy the pages
+	 *	directly.)
+	 */
+	dst_object = vm_object_allocate(
+			(vm_size_t) (dst_entry->end - dst_entry->start));
+
+	dst_entry->object.vm_object = dst_object;
+	dst_entry->offset = 0;
+
+	prot  = dst_entry->max_protection;
+
+	/*
+	 *	Loop through all of the pages in the entry's range, copying
+	 *	each one from the source object (it should be there) to the
+	 *	destination object.
+	 */
+	for (vaddr = dst_entry->start, dst_offset = 0;
+	     vaddr < dst_entry->end;
+	     vaddr += PAGE_SIZE, dst_offset += PAGE_SIZE) {
+
+		/*
+		 *	Allocate a page in the destination object
+		 */
+		vm_object_lock(dst_object);
+		do {
+			dst_m = vm_page_alloc(dst_object, dst_offset);
+			if (dst_m == NULL) {
+				vm_object_unlock(dst_object);
+				VM_WAIT;
+				vm_object_lock(dst_object);
+			}
+		} while (dst_m == NULL);
+
+		/*
+		 *	Find the page in the source object, and copy it in.
+		 *	(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");
+
+		vm_page_copy(src_m, dst_m);
+
+		/*
+		 *	Enter it in the pmap...
+		 */
+		vm_object_unlock(src_object);
+		vm_object_unlock(dst_object);
+
+		pmap_enter(dst_map->pmap, vaddr, VM_PAGE_TO_PHYS(dst_m),
+				prot, FALSE);
+
+		/*
+		 *	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);
+	}
+
+}
diff --git a/sys/vm/vm_glue.c b/sys/vm/vm_glue.c
new file mode 100644
index 0000000..5676ff3
--- /dev/null
+++ b/sys/vm/vm_glue.c
@@ -0,0 +1,605 @@
+/* 
+ * Copyright (c) 1991, 1993
+ *	The Regents of the University of California.  All rights reserved.
+ *
+ * This code is derived from software contributed to Berkeley by
+ * The Mach Operating System project at Carnegie-Mellon University.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. All advertising materials mentioning features or use of this software
+ *    must display the following acknowledgement:
+ *	This product includes software developed by the University of
+ *	California, Berkeley and its contributors.
+ * 4. Neither the name of the University nor the names of its contributors
+ *    may be used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ *
+ *	@(#)vm_glue.c	8.6 (Berkeley) 1/5/94
+ *
+ *
+ * Copyright (c) 1987, 1990 Carnegie-Mellon University.
+ * All rights reserved.
+ * 
+ * Permission to use, copy, modify and distribute this software and
+ * its documentation is hereby granted, provided that both the copyright
+ * notice and this permission notice appear in all copies of the
+ * software, derivative works or modified versions, and any portions
+ * thereof, and that both notices appear in supporting documentation.
+ * 
+ * CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS" 
+ * CONDITION.  CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND 
+ * FOR ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
+ * 
+ * Carnegie Mellon requests users of this software to return to
+ *
+ *  Software Distribution Coordinator  or  Software.Distribution@CS.CMU.EDU
+ *  School of Computer Science
+ *  Carnegie Mellon University
+ *  Pittsburgh PA 15213-3890
+ *
+ * any improvements or extensions that they make and grant Carnegie the
+ * rights to redistribute these changes.
+ */
+
+#include <sys/param.h>
+#include <sys/systm.h>
+#include <sys/proc.h>
+#include <sys/resourcevar.h>
+#include <sys/buf.h>
+#include <sys/user.h>
+
+#include <vm/vm.h>
+#include <vm/vm_page.h>
+#include <vm/vm_kern.h>
+
+#include <machine/cpu.h>
+
+int	avefree = 0;		/* XXX */
+unsigned maxdmap = MAXDSIZ;	/* XXX */
+int	readbuffers = 0;	/* XXX allow kgdb to read kernel buffer pool */
+
+int
+kernacc(addr, len, rw)
+	caddr_t addr;
+	int len, rw;
+{
+	boolean_t rv;
+	vm_offset_t saddr, eaddr;
+	vm_prot_t prot = rw == B_READ ? VM_PROT_READ : VM_PROT_WRITE;
+
+	saddr = trunc_page(addr);
+	eaddr = round_page(addr+len);
+	rv = vm_map_check_protection(kernel_map, saddr, eaddr, prot);
+	/*
+	 * XXX there are still some things (e.g. the buffer cache) that
+	 * are managed behind the VM system's back so even though an
+	 * address is accessible in the mind of the VM system, there may
+	 * not be physical pages where the VM thinks there is.  This can
+	 * lead to bogus allocation of pages in the kernel address space
+	 * or worse, inconsistencies at the pmap level.  We only worry
+	 * about the buffer cache for now.
+	 */
+	if (!readbuffers && rv && (eaddr > (vm_offset_t)buffers &&
+		   saddr < (vm_offset_t)buffers + MAXBSIZE * nbuf))
+		rv = FALSE;
+	return(rv == TRUE);
+}
+
+int
+useracc(addr, len, rw)
+	caddr_t addr;
+	int len, rw;
+{
+	boolean_t rv;
+	vm_prot_t prot = rw == B_READ ? VM_PROT_READ : VM_PROT_WRITE;
+
+	rv = vm_map_check_protection(&curproc->p_vmspace->vm_map,
+	    trunc_page(addr), round_page(addr+len), prot);
+	return(rv == TRUE);
+}
+
+#ifdef KGDB
+/*
+ * Change protections on kernel pages from addr to addr+len
+ * (presumably so debugger can plant a breakpoint).
+ *
+ * We force the protection change at the pmap level.  If we were
+ * to use vm_map_protect a change to allow writing would be lazily-
+ * applied meaning we would still take a protection fault, something
+ * we really don't want to do.  It would also fragment the kernel
+ * map unnecessarily.  We cannot use pmap_protect since it also won't
+ * enforce a write-enable request.  Using pmap_enter is the only way
+ * we can ensure the change takes place properly.
+ */
+void
+chgkprot(addr, len, rw)
+	register caddr_t addr;
+	int len, rw;
+{
+	vm_prot_t prot;
+	vm_offset_t pa, sva, eva;
+
+	prot = rw == B_READ ? VM_PROT_READ : VM_PROT_READ|VM_PROT_WRITE;
+	eva = round_page(addr + len);
+	for (sva = trunc_page(addr); sva < eva; sva += PAGE_SIZE) {
+		/*
+		 * Extract physical address for the page.
+		 * We use a cheezy hack to differentiate physical
+		 * page 0 from an invalid mapping, not that it
+		 * really matters...
+		 */
+		pa = pmap_extract(kernel_pmap, sva|1);
+		if (pa == 0)
+			panic("chgkprot: invalid page");
+		pmap_enter(kernel_pmap, sva, pa&~1, prot, TRUE);
+	}
+}
+#endif
+
+void
+vslock(addr, len)
+	caddr_t	addr;
+	u_int	len;
+{
+	vm_map_pageable(&curproc->p_vmspace->vm_map, trunc_page(addr),
+			round_page(addr+len), FALSE);
+}
+
+void
+vsunlock(addr, len, dirtied)
+	caddr_t	addr;
+	u_int	len;
+	int dirtied;
+{
+#ifdef	lint
+	dirtied++;
+#endif
+	vm_map_pageable(&curproc->p_vmspace->vm_map, trunc_page(addr),
+			round_page(addr+len), TRUE);
+}
+
+/*
+ * Implement fork's actions on an address space.
+ * Here we arrange for the address space to be copied or referenced,
+ * allocate a user struct (pcb and kernel stack), then call the
+ * machine-dependent layer to fill those in and make the new process
+ * ready to run.
+ * NOTE: the kernel stack may be at a different location in the child
+ * process, and thus addresses of automatic variables may be invalid
+ * after cpu_fork returns in the child process.  We do nothing here
+ * after cpu_fork returns.
+ */
+int
+vm_fork(p1, p2, isvfork)
+	register struct proc *p1, *p2;
+	int isvfork;
+{
+	register struct user *up;
+	vm_offset_t addr;
+
+#ifdef i386
+	/*
+	 * avoid copying any of the parent's pagetables or other per-process
+	 * objects that reside in the map by marking all of them non-inheritable
+	 */
+	(void)vm_map_inherit(&p1->p_vmspace->vm_map,
+		UPT_MIN_ADDRESS-UPAGES*NBPG, VM_MAX_ADDRESS, VM_INHERIT_NONE);
+#endif
+	p2->p_vmspace = vmspace_fork(p1->p_vmspace);
+
+#ifdef SYSVSHM
+	if (p1->p_vmspace->vm_shm)
+		shmfork(p1, p2, isvfork);
+#endif
+
+#ifndef	i386
+	/*
+	 * Allocate a wired-down (for now) pcb and kernel stack for the process
+	 */
+	addr = kmem_alloc_pageable(kernel_map, ctob(UPAGES));
+	if (addr == 0)
+		panic("vm_fork: no more kernel virtual memory");
+	vm_map_pageable(kernel_map, addr, addr + ctob(UPAGES), FALSE);
+#else
+/* XXX somehow, on 386, ocassionally pageout removes active, wired down kstack,
+and pagetables, WITHOUT going thru vm_page_unwire! Why this appears to work is
+not yet clear, yet it does... */
+	addr = kmem_alloc(kernel_map, ctob(UPAGES));
+	if (addr == 0)
+		panic("vm_fork: no more kernel virtual memory");
+#endif
+	up = (struct user *)addr;
+	p2->p_addr = up;
+
+	/*
+	 * p_stats and p_sigacts currently point at fields
+	 * in the user struct but not at &u, instead at p_addr.
+	 * Copy p_sigacts and parts of p_stats; zero the rest
+	 * of p_stats (statistics).
+	 */
+	p2->p_stats = &up->u_stats;
+	p2->p_sigacts = &up->u_sigacts;
+	up->u_sigacts = *p1->p_sigacts;
+	bzero(&up->u_stats.pstat_startzero,
+	    (unsigned) ((caddr_t)&up->u_stats.pstat_endzero -
+	    (caddr_t)&up->u_stats.pstat_startzero));
+	bcopy(&p1->p_stats->pstat_startcopy, &up->u_stats.pstat_startcopy,
+	    ((caddr_t)&up->u_stats.pstat_endcopy -
+	     (caddr_t)&up->u_stats.pstat_startcopy));
+
+#ifdef i386
+	{ u_int addr = UPT_MIN_ADDRESS - UPAGES*NBPG; struct vm_map *vp;
+
+	vp = &p2->p_vmspace->vm_map;
+	(void)vm_deallocate(vp, addr, UPT_MAX_ADDRESS - addr);
+	(void)vm_allocate(vp, &addr, UPT_MAX_ADDRESS - addr, FALSE);
+	(void)vm_map_inherit(vp, addr, UPT_MAX_ADDRESS, VM_INHERIT_NONE);
+	}
+#endif
+	/*
+	 * cpu_fork will copy and update the kernel stack and pcb,
+	 * and make the child ready to run.  It marks the child
+	 * so that it can return differently than the parent.
+	 * It returns twice, once in the parent process and
+	 * once in the child.
+	 */
+	return (cpu_fork(p1, p2));
+}
+
+/*
+ * Set default limits for VM system.
+ * Called for proc 0, and then inherited by all others.
+ */
+void
+vm_init_limits(p)
+	register struct proc *p;
+{
+
+	/*
+	 * Set up the initial limits on process VM.
+	 * Set the maximum resident set size to be all
+	 * of (reasonably) available memory.  This causes
+	 * any single, large process to start random page
+	 * replacement once it fills memory.
+	 */
+        p->p_rlimit[RLIMIT_STACK].rlim_cur = DFLSSIZ;
+        p->p_rlimit[RLIMIT_STACK].rlim_max = MAXSSIZ;
+        p->p_rlimit[RLIMIT_DATA].rlim_cur = DFLDSIZ;
+        p->p_rlimit[RLIMIT_DATA].rlim_max = MAXDSIZ;
+	p->p_rlimit[RLIMIT_RSS].rlim_cur = ptoa(cnt.v_free_count);
+}
+
+#include <vm/vm_pageout.h>
+
+#ifdef DEBUG
+int	enableswap = 1;
+int	swapdebug = 0;
+#define	SDB_FOLLOW	1
+#define SDB_SWAPIN	2
+#define SDB_SWAPOUT	4
+#endif
+
+/*
+ * Brutally simple:
+ *	1. Attempt to swapin every swaped-out, runnable process in
+ *	   order of priority.
+ *	2. If not enough memory, wake the pageout daemon and let it
+ *	   clear some space.
+ */
+void
+scheduler()
+{
+	register struct proc *p;
+	register int pri;
+	struct proc *pp;
+	int ppri;
+	vm_offset_t addr;
+	vm_size_t size;
+
+loop:
+#ifdef DEBUG
+	while (!enableswap)
+		sleep((caddr_t)&proc0, PVM);
+#endif
+	pp = NULL;
+	ppri = INT_MIN;
+	for (p = (struct proc *)allproc; p != NULL; p = p->p_next) {
+		if (p->p_stat == SRUN && (p->p_flag & P_INMEM) == 0) {
+			pri = p->p_swtime + p->p_slptime - p->p_nice * 8;
+			if (pri > ppri) {
+				pp = p;
+				ppri = pri;
+			}
+		}
+	}
+#ifdef DEBUG
+	if (swapdebug & SDB_FOLLOW)
+		printf("sched: running, procp %x pri %d\n", pp, ppri);
+#endif
+	/*
+	 * Nothing to do, back to sleep
+	 */
+	if ((p = pp) == NULL) {
+		sleep((caddr_t)&proc0, PVM);
+		goto loop;
+	}
+
+	/*
+	 * We would like to bring someone in.
+	 * This part is really bogus cuz we could deadlock on memory
+	 * despite our feeble check.
+	 */
+	size = round_page(ctob(UPAGES));
+	addr = (vm_offset_t) p->p_addr;
+	if (cnt.v_free_count > atop(size)) {
+#ifdef DEBUG
+		if (swapdebug & SDB_SWAPIN)
+			printf("swapin: pid %d(%s)@%x, pri %d free %d\n",
+			       p->p_pid, p->p_comm, p->p_addr,
+			       ppri, cnt.v_free_count);
+#endif
+		vm_map_pageable(kernel_map, addr, addr+size, FALSE);
+		/*
+		 * Some architectures need to be notified when the
+		 * user area has moved to new physical page(s) (e.g.
+		 * see pmax/pmax/vm_machdep.c).
+		 */
+		cpu_swapin(p);
+		(void) splstatclock();
+		if (p->p_stat == SRUN)
+			setrunqueue(p);
+		p->p_flag |= P_INMEM;
+		(void) spl0();
+		p->p_swtime = 0;
+		goto loop;
+	}
+	/*
+	 * Not enough memory, jab the pageout daemon and wait til the
+	 * coast is clear.
+	 */
+#ifdef DEBUG
+	if (swapdebug & SDB_FOLLOW)
+		printf("sched: no room for pid %d(%s), free %d\n",
+		       p->p_pid, p->p_comm, cnt.v_free_count);
+#endif
+	(void) splhigh();
+	VM_WAIT;
+	(void) spl0();
+#ifdef DEBUG
+	if (swapdebug & SDB_FOLLOW)
+		printf("sched: room again, free %d\n", cnt.v_free_count);
+#endif
+	goto loop;
+}
+
+#define	swappable(p)							\
+	(((p)->p_flag &							\
+	    (P_SYSTEM | P_INMEM | P_NOSWAP | P_WEXIT | P_PHYSIO)) == P_INMEM)
+
+/*
+ * Swapout is driven by the pageout daemon.  Very simple, we find eligible
+ * procs and unwire their u-areas.  We try to always "swap" at least one
+ * process in case we need the room for a swapin.
+ * If any procs have been sleeping/stopped for at least maxslp seconds,
+ * they are swapped.  Else, we swap the longest-sleeping or stopped process,
+ * if any, otherwise the longest-resident process.
+ */
+void
+swapout_threads()
+{
+	register struct proc *p;
+	struct proc *outp, *outp2;
+	int outpri, outpri2;
+	int didswap = 0;
+	extern int maxslp;
+
+#ifdef DEBUG
+	if (!enableswap)
+		return;
+#endif
+	outp = outp2 = NULL;
+	outpri = outpri2 = 0;
+	for (p = (struct proc *)allproc; p != NULL; p = p->p_next) {
+		if (!swappable(p))
+			continue;
+		switch (p->p_stat) {
+		case SRUN:
+			if (p->p_swtime > outpri2) {
+				outp2 = p;
+				outpri2 = p->p_swtime;
+			}
+			continue;
+			
+		case SSLEEP:
+		case SSTOP:
+			if (p->p_slptime >= maxslp) {
+				swapout(p);
+				didswap++;
+			} else if (p->p_slptime > outpri) {
+				outp = p;
+				outpri = p->p_slptime;
+			}
+			continue;
+		}
+	}
+	/*
+	 * If we didn't get rid of any real duds, toss out the next most
+	 * likely sleeping/stopped or running candidate.  We only do this
+	 * if we are real low on memory since we don't gain much by doing
+	 * it (UPAGES pages).
+	 */
+	if (didswap == 0 &&
+	    cnt.v_free_count <= atop(round_page(ctob(UPAGES)))) {
+		if ((p = outp) == 0)
+			p = outp2;
+#ifdef DEBUG
+		if (swapdebug & SDB_SWAPOUT)
+			printf("swapout_threads: no duds, try procp %x\n", p);
+#endif
+		if (p)
+			swapout(p);
+	}
+}
+
+void
+swapout(p)
+	register struct proc *p;
+{
+	vm_offset_t addr;
+	vm_size_t size;
+
+#ifdef DEBUG
+	if (swapdebug & SDB_SWAPOUT)
+		printf("swapout: pid %d(%s)@%x, stat %x pri %d free %d\n",
+		       p->p_pid, p->p_comm, p->p_addr, p->p_stat,
+		       p->p_slptime, cnt.v_free_count);
+#endif
+	size = round_page(ctob(UPAGES));
+	addr = (vm_offset_t) p->p_addr;
+#if defined(hp300) || defined(luna68k)
+	/*
+	 * Ugh!  u-area is double mapped to a fixed address behind the
+	 * back of the VM system and accesses are usually through that
+	 * address rather than the per-process address.  Hence reference
+	 * and modify information are recorded at the fixed address and
+	 * lost at context switch time.  We assume the u-struct and
+	 * kernel stack are always accessed/modified and force it to be so.
+	 */
+	{
+		register int i;
+		volatile long tmp;
+
+		for (i = 0; i < UPAGES; i++) {
+			tmp = *(long *)addr; *(long *)addr = tmp;
+			addr += NBPG;
+		}
+		addr = (vm_offset_t) p->p_addr;
+	}
+#endif
+#ifdef mips
+	/*
+	 * Be sure to save the floating point coprocessor state before
+	 * paging out the u-struct.
+	 */
+	{
+		extern struct proc *machFPCurProcPtr;
+
+		if (p == machFPCurProcPtr) {
+			MachSaveCurFPState(p);
+			machFPCurProcPtr = (struct proc *)0;
+		}
+	}
+#endif
+#ifndef	i386 /* temporary measure till we find spontaineous unwire of kstack */
+	vm_map_pageable(kernel_map, addr, addr+size, TRUE);
+	pmap_collect(vm_map_pmap(&p->p_vmspace->vm_map));
+#endif
+	(void) splhigh();
+	p->p_flag &= ~P_INMEM;
+	if (p->p_stat == SRUN)
+		remrq(p);
+	(void) spl0();
+	p->p_swtime = 0;
+}
+
+/*
+ * The rest of these routines fake thread handling
+ */
+
+void
+assert_wait(event, ruptible)
+	int event;
+	boolean_t ruptible;
+{
+#ifdef lint
+	ruptible++;
+#endif
+	curproc->p_thread = event;
+}
+
+void
+thread_block()
+{
+	int s = splhigh();
+
+	if (curproc->p_thread)
+		sleep((caddr_t)curproc->p_thread, PVM);
+	splx(s);
+}
+
+void
+thread_sleep(event, lock, ruptible)
+	int event;
+	simple_lock_t lock;
+	boolean_t ruptible;
+{
+#ifdef lint
+	ruptible++;
+#endif
+	int s = splhigh();
+
+	curproc->p_thread = event;
+	simple_unlock(lock);
+	if (curproc->p_thread)
+		sleep((caddr_t)event, PVM);
+	splx(s);
+}
+
+void
+thread_wakeup(event)
+	int event;
+{
+	int s = splhigh();
+
+	wakeup((caddr_t)event);
+	splx(s);
+}
+
+/*
+ * DEBUG stuff
+ */
+
+int indent = 0;
+
+#include <machine/stdarg.h>		/* see subr_prf.c */
+
+/*ARGSUSED2*/
+void
+#if __STDC__
+iprintf(const char *fmt, ...)
+#else
+iprintf(fmt /* , va_alist */)
+	char *fmt;
+	/* va_dcl */
+#endif
+{
+	register int i;
+	va_list ap;
+
+	for (i = indent; i >= 8; i -= 8)
+		printf("\t");
+	while (--i >= 0)
+		printf(" ");
+	va_start(ap, fmt);
+	printf("%r", fmt, ap);
+	va_end(ap);
+}
diff --git a/sys/vm/vm_inherit.h b/sys/vm/vm_inherit.h
new file mode 100644
index 0000000..455f91c
--- /dev/null
+++ b/sys/vm/vm_inherit.h
@@ -0,0 +1,83 @@
+/* 
+ * Copyright (c) 1991, 1993
+ *	The Regents of the University of California.  All rights reserved.
+ *
+ * This code is derived from software contributed to Berkeley by
+ * The Mach Operating System project at Carnegie-Mellon University.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. All advertising materials mentioning features or use of this software
+ *    must display the following acknowledgement:
+ *	This product includes software developed by the University of
+ *	California, Berkeley and its contributors.
+ * 4. Neither the name of the University nor the names of its contributors
+ *    may be used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ *
+ *	@(#)vm_inherit.h	8.1 (Berkeley) 6/11/93
+ *
+ *
+ * Copyright (c) 1987, 1990 Carnegie-Mellon University.
+ * All rights reserved.
+ *
+ * Authors: Avadis Tevanian, Jr., Michael Wayne Young
+ * 
+ * Permission to use, copy, modify and distribute this software and
+ * its documentation is hereby granted, provided that both the copyright
+ * notice and this permission notice appear in all copies of the
+ * software, derivative works or modified versions, and any portions
+ * thereof, and that both notices appear in supporting documentation.
+ * 
+ * CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS" 
+ * CONDITION.  CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND 
+ * FOR ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
+ * 
+ * Carnegie Mellon requests users of this software to return to
+ *
+ *  Software Distribution Coordinator  or  Software.Distribution@CS.CMU.EDU
+ *  School of Computer Science
+ *  Carnegie Mellon University
+ *  Pittsburgh PA 15213-3890
+ *
+ * any improvements or extensions that they make and grant Carnegie the
+ * rights to redistribute these changes.
+ */
+
+/*
+ *	Virtual memory map inheritance definitions.
+ */
+
+#ifndef	_VM_INHERIT_
+#define	_VM_INHERIT_
+
+/*
+ *	Enumeration of valid values for vm_inherit_t.
+ */
+
+#define	VM_INHERIT_SHARE	((vm_inherit_t) 0)	/* share with child */
+#define	VM_INHERIT_COPY		((vm_inherit_t) 1)	/* copy into child */
+#define VM_INHERIT_NONE		((vm_inherit_t) 2)	/* absent from child */
+#define	VM_INHERIT_DONATE_COPY	((vm_inherit_t) 3)	/* copy and delete */
+
+#define VM_INHERIT_DEFAULT	VM_INHERIT_COPY
+
+#endif /* _VM_INHERIT_ */
diff --git a/sys/vm/vm_init.c b/sys/vm/vm_init.c
new file mode 100644
index 0000000..4874f9e
--- /dev/null
+++ b/sys/vm/vm_init.c
@@ -0,0 +1,103 @@
+/* 
+ * Copyright (c) 1991, 1993
+ *	The Regents of the University of California.  All rights reserved.
+ *
+ * This code is derived from software contributed to Berkeley by
+ * The Mach Operating System project at Carnegie-Mellon University.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. All advertising materials mentioning features or use of this software
+ *    must display the following acknowledgement:
+ *	This product includes software developed by the University of
+ *	California, Berkeley and its contributors.
+ * 4. Neither the name of the University nor the names of its contributors
+ *    may be used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ *
+ *	@(#)vm_init.c	8.1 (Berkeley) 6/11/93
+ *
+ *
+ * Copyright (c) 1987, 1990 Carnegie-Mellon University.
+ * All rights reserved.
+ *
+ * Authors: Avadis Tevanian, Jr., Michael Wayne Young
+ * 
+ * Permission to use, copy, modify and distribute this software and
+ * its documentation is hereby granted, provided that both the copyright
+ * notice and this permission notice appear in all copies of the
+ * software, derivative works or modified versions, and any portions
+ * thereof, and that both notices appear in supporting documentation.
+ * 
+ * CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS" 
+ * CONDITION.  CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND 
+ * FOR ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
+ * 
+ * Carnegie Mellon requests users of this software to return to
+ *
+ *  Software Distribution Coordinator  or  Software.Distribution@CS.CMU.EDU
+ *  School of Computer Science
+ *  Carnegie Mellon University
+ *  Pittsburgh PA 15213-3890
+ *
+ * any improvements or extensions that they make and grant Carnegie the
+ * rights to redistribute these changes.
+ */
+
+/*
+ *	Initialize the Virtual Memory subsystem.
+ */
+
+#include <sys/param.h>
+
+#include <vm/vm.h>
+#include <vm/vm_page.h>
+#include <vm/vm_kern.h>
+
+/*
+ *	vm_init initializes the virtual memory system.
+ *	This is done only by the first cpu up.
+ *
+ *	The start and end address of physical memory is passed in.
+ */
+
+void vm_mem_init()
+{
+	extern vm_offset_t	avail_start, avail_end;
+	extern vm_offset_t	virtual_avail, virtual_end;
+
+	/*
+	 *	Initializes resident memory structures.
+	 *	From here on, all physical memory is accounted for,
+	 *	and we use only virtual addresses.
+	 */
+	vm_set_page_size();
+	vm_page_startup(&avail_start, &avail_end);
+
+	/*
+	 * Initialize other VM packages
+	 */
+	vm_object_init(virtual_end - VM_MIN_KERNEL_ADDRESS);
+	vm_map_startup();
+	kmem_init(virtual_avail, virtual_end);
+	pmap_init(avail_start, avail_end);
+	vm_pager_init();
+}
diff --git a/sys/vm/vm_kern.c b/sys/vm/vm_kern.c
new file mode 100644
index 0000000..7e4db63
--- /dev/null
+++ b/sys/vm/vm_kern.c
@@ -0,0 +1,450 @@
+/* 
+ * Copyright (c) 1991, 1993
+ *	The Regents of the University of California.  All rights reserved.
+ *
+ * This code is derived from software contributed to Berkeley by
+ * The Mach Operating System project at Carnegie-Mellon University.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. All advertising materials mentioning features or use of this software
+ *    must display the following acknowledgement:
+ *	This product includes software developed by the University of
+ *	California, Berkeley and its contributors.
+ * 4. Neither the name of the University nor the names of its contributors
+ *    may be used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ *
+ *	@(#)vm_kern.c	8.3 (Berkeley) 1/12/94
+ *
+ *
+ * Copyright (c) 1987, 1990 Carnegie-Mellon University.
+ * All rights reserved.
+ *
+ * Authors: Avadis Tevanian, Jr., Michael Wayne Young
+ * 
+ * Permission to use, copy, modify and distribute this software and
+ * its documentation is hereby granted, provided that both the copyright
+ * notice and this permission notice appear in all copies of the
+ * software, derivative works or modified versions, and any portions
+ * thereof, and that both notices appear in supporting documentation.
+ * 
+ * CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS" 
+ * CONDITION.  CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND 
+ * FOR ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
+ * 
+ * Carnegie Mellon requests users of this software to return to
+ *
+ *  Software Distribution Coordinator  or  Software.Distribution@CS.CMU.EDU
+ *  School of Computer Science
+ *  Carnegie Mellon University
+ *  Pittsburgh PA 15213-3890
+ *
+ * any improvements or extensions that they make and grant Carnegie the
+ * rights to redistribute these changes.
+ */
+
+/*
+ *	Kernel memory management.
+ */
+
+#include <sys/param.h>
+#include <sys/systm.h>
+
+#include <vm/vm.h>
+#include <vm/vm_page.h>
+#include <vm/vm_pageout.h>
+#include <vm/vm_kern.h>
+
+/*
+ *	kmem_alloc_pageable:
+ *
+ *	Allocate pageable memory to the kernel's address map.
+ *	map must be "kernel_map" below.
+ */
+
+vm_offset_t kmem_alloc_pageable(map, size)
+	vm_map_t		map;
+	register vm_size_t	size;
+{
+	vm_offset_t		addr;
+	register int		result;
+
+#if	0
+	if (map != kernel_map)
+		panic("kmem_alloc_pageable: not called with kernel_map");
+#endif
+
+	size = round_page(size);
+
+	addr = vm_map_min(map);
+	result = vm_map_find(map, NULL, (vm_offset_t) 0,
+				&addr, size, TRUE);
+	if (result != KERN_SUCCESS) {
+		return(0);
+	}
+
+	return(addr);
+}
+
+/*
+ *	Allocate wired-down memory in the kernel's address map
+ *	or a submap.
+ */
+vm_offset_t kmem_alloc(map, size)
+	register vm_map_t	map;
+	register vm_size_t	size;
+{
+	vm_offset_t		addr;
+	register vm_offset_t	offset;
+	extern vm_object_t	kernel_object;
+	vm_offset_t		i;
+
+	size = round_page(size);
+
+	/*
+	 *	Use the kernel object for wired-down kernel pages.
+	 *	Assume that no region of the kernel object is
+	 *	referenced more than once.
+	 */
+
+	/*
+	 * Locate sufficient space in the map.  This will give us the
+	 * final virtual address for the new memory, and thus will tell
+	 * us the offset within the kernel map.
+	 */
+	vm_map_lock(map);
+	if (vm_map_findspace(map, 0, size, &addr)) {
+		vm_map_unlock(map);
+		return (0);
+	}
+	offset = addr - VM_MIN_KERNEL_ADDRESS;
+	vm_object_reference(kernel_object);
+	vm_map_insert(map, kernel_object, offset, addr, addr + size);
+	vm_map_unlock(map);
+
+	/*
+	 *	Guarantee that there are pages already in this object
+	 *	before calling vm_map_pageable.  This is to prevent the
+	 *	following scenario:
+	 *
+	 *		1) Threads have swapped out, so that there is a
+	 *		   pager for the kernel_object.
+	 *		2) The kmsg zone is empty, and so we are kmem_allocing
+	 *		   a new page for it.
+	 *		3) vm_map_pageable calls vm_fault; there is no page,
+	 *		   but there is a pager, so we call
+	 *		   pager_data_request.  But the kmsg zone is empty,
+	 *		   so we must kmem_alloc.
+	 *		4) goto 1
+	 *		5) Even if the kmsg zone is not empty: when we get
+	 *		   the data back from the pager, it will be (very
+	 *		   stale) non-zero data.  kmem_alloc is defined to
+	 *		   return zero-filled memory.
+	 *
+	 *	We're intentionally not activating the pages we allocate
+	 *	to prevent a race with page-out.  vm_map_pageable will wire
+	 *	the pages.
+	 */
+
+	vm_object_lock(kernel_object);
+	for (i = 0 ; i < size; i+= PAGE_SIZE) {
+		vm_page_t	mem;
+
+		while ((mem = vm_page_alloc(kernel_object, offset+i)) == NULL) {
+			vm_object_unlock(kernel_object);
+			VM_WAIT;
+			vm_object_lock(kernel_object);
+		}
+		vm_page_zero_fill(mem);
+		mem->flags &= ~PG_BUSY;
+	}
+	vm_object_unlock(kernel_object);
+		
+	/*
+	 *	And finally, mark the data as non-pageable.
+	 */
+
+	(void) vm_map_pageable(map, (vm_offset_t) addr, addr + size, FALSE);
+
+	/*
+	 *	Try to coalesce the map
+	 */
+
+	vm_map_simplify(map, addr);
+
+	return(addr);
+}
+
+/*
+ *	kmem_free:
+ *
+ *	Release a region of kernel virtual memory allocated
+ *	with kmem_alloc, and return the physical pages
+ *	associated with that region.
+ */
+void kmem_free(map, addr, size)
+	vm_map_t		map;
+	register vm_offset_t	addr;
+	vm_size_t		size;
+{
+	(void) vm_map_remove(map, trunc_page(addr), round_page(addr + size));
+}
+
+/*
+ *	kmem_suballoc:
+ *
+ *	Allocates a map to manage a subrange
+ *	of the kernel virtual address space.
+ *
+ *	Arguments are as follows:
+ *
+ *	parent		Map to take range from
+ *	size		Size of range to find
+ *	min, max	Returned endpoints of map
+ *	pageable	Can the region be paged
+ */
+vm_map_t kmem_suballoc(parent, min, max, size, pageable)
+	register vm_map_t	parent;
+	vm_offset_t		*min, *max;
+	register vm_size_t	size;
+	boolean_t		pageable;
+{
+	register int	ret;
+	vm_map_t	result;
+
+	size = round_page(size);
+
+	*min = (vm_offset_t) vm_map_min(parent);
+	ret = vm_map_find(parent, NULL, (vm_offset_t) 0,
+				min, size, TRUE);
+	if (ret != KERN_SUCCESS) {
+		printf("kmem_suballoc: bad status return of %d.\n", ret);
+		panic("kmem_suballoc");
+	}
+	*max = *min + size;
+	pmap_reference(vm_map_pmap(parent));
+	result = vm_map_create(vm_map_pmap(parent), *min, *max, pageable);
+	if (result == NULL)
+		panic("kmem_suballoc: cannot create submap");
+	if ((ret = vm_map_submap(parent, *min, *max, result)) != KERN_SUCCESS)
+		panic("kmem_suballoc: unable to change range to submap");
+	return(result);
+}
+
+/*
+ * Allocate wired-down memory in the kernel's address map for the higher
+ * level kernel memory allocator (kern/kern_malloc.c).  We cannot use
+ * kmem_alloc() because we may need to allocate memory at interrupt
+ * level where we cannot block (canwait == FALSE).
+ *
+ * This routine has its own private kernel submap (kmem_map) and object
+ * (kmem_object).  This, combined with the fact that only malloc uses
+ * this routine, ensures that we will never block in map or object waits.
+ *
+ * Note that this still only works in a uni-processor environment and
+ * when called at splhigh().
+ *
+ * We don't worry about expanding the map (adding entries) since entries
+ * for wired maps are statically allocated.
+ */
+vm_offset_t
+kmem_malloc(map, size, canwait)
+	register vm_map_t	map;
+	register vm_size_t	size;
+	boolean_t		canwait;
+{
+	register vm_offset_t	offset, i;
+	vm_map_entry_t		entry;
+	vm_offset_t		addr;
+	vm_page_t		m;
+	extern vm_object_t	kmem_object;
+
+	if (map != kmem_map && map != mb_map)
+		panic("kern_malloc_alloc: map != {kmem,mb}_map");
+
+	size = round_page(size);
+	addr = vm_map_min(map);
+
+	/*
+	 * Locate sufficient space in the map.  This will give us the
+	 * final virtual address for the new memory, and thus will tell
+	 * us the offset within the kernel map.
+	 */
+	vm_map_lock(map);
+	if (vm_map_findspace(map, 0, size, &addr)) {
+		vm_map_unlock(map);
+		if (canwait)		/* XXX  should wait */
+			panic("kmem_malloc: %s too small",
+			    map == kmem_map ? "kmem_map" : "mb_map");
+		return (0);
+	}
+	offset = addr - vm_map_min(kmem_map);
+	vm_object_reference(kmem_object);
+	vm_map_insert(map, kmem_object, offset, addr, addr + size);
+
+	/*
+	 * If we can wait, just mark the range as wired
+	 * (will fault pages as necessary).
+	 */
+	if (canwait) {
+		vm_map_unlock(map);
+		(void) vm_map_pageable(map, (vm_offset_t) addr, addr + size,
+				       FALSE);
+		vm_map_simplify(map, addr);
+		return(addr);
+	}
+
+	/*
+	 * If we cannot wait then we must allocate all memory up front,
+	 * pulling it off the active queue to prevent pageout.
+	 */
+	vm_object_lock(kmem_object);
+	for (i = 0; i < size; i += PAGE_SIZE) {
+		m = vm_page_alloc(kmem_object, offset + i);
+
+		/*
+		 * Ran out of space, free everything up and return.
+		 * Don't need to lock page queues here as we know
+		 * that the pages we got aren't on any queues.
+		 */
+		if (m == NULL) {
+			while (i != 0) {
+				i -= PAGE_SIZE;
+				m = vm_page_lookup(kmem_object, offset + i);
+				vm_page_free(m);
+			}
+			vm_object_unlock(kmem_object);
+			vm_map_delete(map, addr, addr + size);
+			vm_map_unlock(map);
+			return(0);
+		}
+#if 0
+		vm_page_zero_fill(m);
+#endif
+		m->flags &= ~PG_BUSY;
+	}
+	vm_object_unlock(kmem_object);
+
+	/*
+	 * Mark map entry as non-pageable.
+	 * Assert: vm_map_insert() will never be able to extend the previous
+	 * entry so there will be a new entry exactly corresponding to this
+	 * address range and it will have wired_count == 0.
+	 */
+	if (!vm_map_lookup_entry(map, addr, &entry) ||
+	    entry->start != addr || entry->end != addr + size ||
+	    entry->wired_count)
+		panic("kmem_malloc: entry not found or misaligned");
+	entry->wired_count++;
+
+	/*
+	 * Loop thru pages, entering them in the pmap.
+	 * (We cannot add them to the wired count without
+	 * wrapping the vm_page_queue_lock in splimp...)
+	 */
+	for (i = 0; i < size; i += PAGE_SIZE) {
+		vm_object_lock(kmem_object);
+		m = vm_page_lookup(kmem_object, offset + i);
+		vm_object_unlock(kmem_object);
+		pmap_enter(map->pmap, addr + i, VM_PAGE_TO_PHYS(m),
+			   VM_PROT_DEFAULT, TRUE);
+	}
+	vm_map_unlock(map);
+
+	vm_map_simplify(map, addr);
+	return(addr);
+}
+
+/*
+ *	kmem_alloc_wait
+ *
+ *	Allocates pageable memory from a sub-map of the kernel.  If the submap
+ *	has no room, the caller sleeps waiting for more memory in the submap.
+ *
+ */
+vm_offset_t kmem_alloc_wait(map, size)
+	vm_map_t	map;
+	vm_size_t	size;
+{
+	vm_offset_t	addr;
+
+	size = round_page(size);
+
+	for (;;) {
+		/*
+		 * To make this work for more than one map,
+		 * use the map's lock to lock out sleepers/wakers.
+		 */
+		vm_map_lock(map);
+		if (vm_map_findspace(map, 0, size, &addr) == 0)
+			break;
+		/* no space now; see if we can ever get space */
+		if (vm_map_max(map) - vm_map_min(map) < size) {
+			vm_map_unlock(map);
+			return (0);
+		}
+		assert_wait((int)map, TRUE);
+		vm_map_unlock(map);
+		thread_block();
+	}
+	vm_map_insert(map, NULL, (vm_offset_t)0, addr, addr + size);
+	vm_map_unlock(map);
+	return (addr);
+}
+
+/*
+ *	kmem_free_wakeup
+ *
+ *	Returns memory to a submap of the kernel, and wakes up any threads
+ *	waiting for memory in that map.
+ */
+void	kmem_free_wakeup(map, addr, size)
+	vm_map_t	map;
+	vm_offset_t	addr;
+	vm_size_t	size;
+{
+	vm_map_lock(map);
+	(void) vm_map_delete(map, trunc_page(addr), round_page(addr + size));
+	thread_wakeup((int)map);
+	vm_map_unlock(map);
+}
+
+/*
+ * Create the kernel map; insert a mapping covering kernel text, data, bss,
+ * and all space allocated thus far (`boostrap' data).  The new map will thus
+ * map the range between VM_MIN_KERNEL_ADDRESS and `start' as allocated, and
+ * the range between `start' and `end' as free.
+ */
+void kmem_init(start, end)
+	vm_offset_t start, end;
+{
+	register vm_map_t m;
+
+	m = vm_map_create(kernel_pmap, VM_MIN_KERNEL_ADDRESS, end, FALSE);
+	vm_map_lock(m);
+	/* N.B.: cannot use kgdb to debug, starting with this assignment ... */
+	kernel_map = m;
+	(void) vm_map_insert(m, NULL, (vm_offset_t)0,
+	    VM_MIN_KERNEL_ADDRESS, start);
+	/* ... and ending with the completion of the above `insert' */
+	vm_map_unlock(m);
+}
diff --git a/sys/vm/vm_kern.h b/sys/vm/vm_kern.h
new file mode 100644
index 0000000..d0d2c35
--- /dev/null
+++ b/sys/vm/vm_kern.h
@@ -0,0 +1,72 @@
+/* 
+ * Copyright (c) 1991, 1993
+ *	The Regents of the University of California.  All rights reserved.
+ *
+ * This code is derived from software contributed to Berkeley by
+ * The Mach Operating System project at Carnegie-Mellon University.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. All advertising materials mentioning features or use of this software
+ *    must display the following acknowledgement:
+ *	This product includes software developed by the University of
+ *	California, Berkeley and its contributors.
+ * 4. Neither the name of the University nor the names of its contributors
+ *    may be used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ *
+ *	@(#)vm_kern.h	8.1 (Berkeley) 6/11/93
+ *
+ *
+ * Copyright (c) 1987, 1990 Carnegie-Mellon University.
+ * All rights reserved.
+ *
+ * Authors: Avadis Tevanian, Jr., Michael Wayne Young
+ * 
+ * Permission to use, copy, modify and distribute this software and
+ * its documentation is hereby granted, provided that both the copyright
+ * notice and this permission notice appear in all copies of the
+ * software, derivative works or modified versions, and any portions
+ * thereof, and that both notices appear in supporting documentation.
+ * 
+ * CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS" 
+ * CONDITION.  CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND 
+ * FOR ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
+ * 
+ * Carnegie Mellon requests users of this software to return to
+ *
+ *  Software Distribution Coordinator  or  Software.Distribution@CS.CMU.EDU
+ *  School of Computer Science
+ *  Carnegie Mellon University
+ *  Pittsburgh PA 15213-3890
+ *
+ * any improvements or extensions that they make and grant Carnegie the
+ * rights to redistribute these changes.
+ */
+
+/* Kernel memory management definitions. */
+
+vm_map_t	buffer_map;
+vm_map_t	exec_map;
+vm_map_t	kernel_map;
+vm_map_t	kmem_map;
+vm_map_t	mb_map;
+vm_map_t	phys_map;
diff --git a/sys/vm/vm_map.c b/sys/vm/vm_map.c
new file mode 100644
index 0000000..425fe0d
--- /dev/null
+++ b/sys/vm/vm_map.c
@@ -0,0 +1,2626 @@
+/* 
+ * Copyright (c) 1991, 1993
+ *	The Regents of the University of California.  All rights reserved.
+ *
+ * This code is derived from software contributed to Berkeley by
+ * The Mach Operating System project at Carnegie-Mellon University.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. All advertising materials mentioning features or use of this software
+ *    must display the following acknowledgement:
+ *	This product includes software developed by the University of
+ *	California, Berkeley and its contributors.
+ * 4. Neither the name of the University nor the names of its contributors
+ *    may be used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ *
+ *	@(#)vm_map.c	8.3 (Berkeley) 1/12/94
+ *
+ *
+ * Copyright (c) 1987, 1990 Carnegie-Mellon University.
+ * All rights reserved.
+ *
+ * Authors: Avadis Tevanian, Jr., Michael Wayne Young
+ * 
+ * Permission to use, copy, modify and distribute this software and
+ * its documentation is hereby granted, provided that both the copyright
+ * notice and this permission notice appear in all copies of the
+ * software, derivative works or modified versions, and any portions
+ * thereof, and that both notices appear in supporting documentation.
+ * 
+ * CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS" 
+ * CONDITION.  CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND 
+ * FOR ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
+ * 
+ * Carnegie Mellon requests users of this software to return to
+ *
+ *  Software Distribution Coordinator  or  Software.Distribution@CS.CMU.EDU
+ *  School of Computer Science
+ *  Carnegie Mellon University
+ *  Pittsburgh PA 15213-3890
+ *
+ * any improvements or extensions that they make and grant Carnegie the
+ * rights to redistribute these changes.
+ */
+
+/*
+ *	Virtual memory mapping module.
+ */
+
+#include <sys/param.h>
+#include <sys/systm.h>
+#include <sys/malloc.h>
+
+#include <vm/vm.h>
+#include <vm/vm_page.h>
+#include <vm/vm_object.h>
+
+/*
+ *	Virtual memory maps provide for the mapping, protection,
+ *	and sharing of virtual memory objects.  In addition,
+ *	this module provides for an efficient virtual copy of
+ *	memory from one map to another.
+ *
+ *	Synchronization is required prior to most operations.
+ *
+ *	Maps consist of an ordered doubly-linked list of simple
+ *	entries; a single hint is used to speed up lookups.
+ *
+ *	In order to properly represent the sharing of virtual
+ *	memory regions among maps, the map structure is bi-level.
+ *	Top-level ("address") maps refer to regions of sharable
+ *	virtual memory.  These regions are implemented as
+ *	("sharing") maps, which then refer to the actual virtual
+ *	memory objects.  When two address maps "share" memory,
+ *	their top-level maps both have references to the same
+ *	sharing map.  When memory is virtual-copied from one
+ *	address map to another, the references in the sharing
+ *	maps are actually copied -- no copying occurs at the
+ *	virtual memory object level.
+ *
+ *	Since portions of maps are specified by start/end addreses,
+ *	which may not align with existing map entries, all
+ *	routines merely "clip" entries to these start/end values.
+ *	[That is, an entry is split into two, bordering at a
+ *	start or end value.]  Note that these clippings may not
+ *	always be necessary (as the two resulting entries are then
+ *	not changed); however, the clipping is done for convenience.
+ *	No attempt is currently made to "glue back together" two
+ *	abutting entries.
+ *
+ *	As mentioned above, virtual copy operations are performed
+ *	by copying VM object references from one sharing map to
+ *	another, and then marking both regions as copy-on-write.
+ *	It is important to note that only one writeable reference
+ *	to a VM object region exists in any map -- this means that
+ *	shadow object creation can be delayed until a write operation
+ *	occurs.
+ */
+
+/*
+ *	vm_map_startup:
+ *
+ *	Initialize the vm_map module.  Must be called before
+ *	any other vm_map routines.
+ *
+ *	Map and entry structures are allocated from the general
+ *	purpose memory pool with some exceptions:
+ *
+ *	- The kernel map and kmem submap are allocated statically.
+ *	- Kernel map entries are allocated out of a static pool.
+ *
+ *	These restrictions are necessary since malloc() uses the
+ *	maps and requires map entries.
+ */
+
+vm_offset_t	kentry_data;
+vm_size_t	kentry_data_size;
+vm_map_entry_t	kentry_free;
+vm_map_t	kmap_free;
+
+static void	_vm_map_clip_end __P((vm_map_t, vm_map_entry_t, vm_offset_t));
+static void	_vm_map_clip_start __P((vm_map_t, vm_map_entry_t, vm_offset_t));
+
+void vm_map_startup()
+{
+	register int i;
+	register vm_map_entry_t mep;
+	vm_map_t mp;
+
+	/*
+	 * Static map structures for allocation before initialization of
+	 * kernel map or kmem map.  vm_map_create knows how to deal with them.
+	 */
+	kmap_free = mp = (vm_map_t) kentry_data;
+	i = MAX_KMAP;
+	while (--i > 0) {
+		mp->header.next = (vm_map_entry_t) (mp + 1);
+		mp++;
+	}
+	mp++->header.next = NULL;
+
+	/*
+	 * Form a free list of statically allocated kernel map entries
+	 * with the rest.
+	 */
+	kentry_free = mep = (vm_map_entry_t) mp;
+	i = (kentry_data_size - MAX_KMAP * sizeof *mp) / sizeof *mep;
+	while (--i > 0) {
+		mep->next = mep + 1;
+		mep++;
+	}
+	mep->next = NULL;
+}
+
+/*
+ * Allocate a vmspace structure, including a vm_map and pmap,
+ * and initialize those structures.  The refcnt is set to 1.
+ * The remaining fields must be initialized by the caller.
+ */
+struct vmspace *
+vmspace_alloc(min, max, pageable)
+	vm_offset_t min, max;
+	int pageable;
+{
+	register struct vmspace *vm;
+
+	MALLOC(vm, struct vmspace *, sizeof(struct vmspace), M_VMMAP, M_WAITOK);
+	bzero(vm, (caddr_t) &vm->vm_startcopy - (caddr_t) vm);
+	vm_map_init(&vm->vm_map, min, max, pageable);
+	pmap_pinit(&vm->vm_pmap);
+	vm->vm_map.pmap = &vm->vm_pmap;		/* XXX */
+	vm->vm_refcnt = 1;
+	return (vm);
+}
+
+void
+vmspace_free(vm)
+	register struct vmspace *vm;
+{
+
+	if (--vm->vm_refcnt == 0) {
+		/*
+		 * Lock the map, to wait out all other references to it.
+		 * Delete all of the mappings and pages they hold,
+		 * then call the pmap module to reclaim anything left.
+		 */
+		vm_map_lock(&vm->vm_map);
+		(void) vm_map_delete(&vm->vm_map, vm->vm_map.min_offset,
+		    vm->vm_map.max_offset);
+		pmap_release(&vm->vm_pmap);
+		FREE(vm, M_VMMAP);
+	}
+}
+
+/*
+ *	vm_map_create:
+ *
+ *	Creates and returns a new empty VM map with
+ *	the given physical map structure, and having
+ *	the given lower and upper address bounds.
+ */
+vm_map_t vm_map_create(pmap, min, max, pageable)
+	pmap_t		pmap;
+	vm_offset_t	min, max;
+	boolean_t	pageable;
+{
+	register vm_map_t	result;
+	extern vm_map_t		kmem_map;
+
+	if (kmem_map == NULL) {
+		result = kmap_free;
+		kmap_free = (vm_map_t) result->header.next;
+		if (result == NULL)
+			panic("vm_map_create: out of maps");
+	} else
+		MALLOC(result, vm_map_t, sizeof(struct vm_map),
+		       M_VMMAP, M_WAITOK);
+
+	vm_map_init(result, min, max, pageable);
+	result->pmap = pmap;
+	return(result);
+}
+
+/*
+ * Initialize an existing vm_map structure
+ * such as that in the vmspace structure.
+ * The pmap is set elsewhere.
+ */
+void
+vm_map_init(map, min, max, pageable)
+	register struct vm_map *map;
+	vm_offset_t	min, max;
+	boolean_t	pageable;
+{
+	map->header.next = map->header.prev = &map->header;
+	map->nentries = 0;
+	map->size = 0;
+	map->ref_count = 1;
+	map->is_main_map = TRUE;
+	map->min_offset = min;
+	map->max_offset = max;
+	map->entries_pageable = pageable;
+	map->first_free = &map->header;
+	map->hint = &map->header;
+	map->timestamp = 0;
+	lock_init(&map->lock, TRUE);
+	simple_lock_init(&map->ref_lock);
+	simple_lock_init(&map->hint_lock);
+}
+
+/*
+ *	vm_map_entry_create:	[ internal use only ]
+ *
+ *	Allocates a VM map entry for insertion.
+ *	No entry fields are filled in.  This routine is
+ */
+vm_map_entry_t vm_map_entry_create(map)
+	vm_map_t	map;
+{
+	vm_map_entry_t	entry;
+#ifdef DEBUG
+	extern vm_map_t		kernel_map, kmem_map, mb_map, pager_map;
+	boolean_t		isspecial;
+
+	isspecial = (map == kernel_map || map == kmem_map ||
+		     map == mb_map || map == pager_map);
+	if (isspecial && map->entries_pageable ||
+	    !isspecial && !map->entries_pageable)
+		panic("vm_map_entry_create: bogus map");
+#endif
+	if (map->entries_pageable) {
+		MALLOC(entry, vm_map_entry_t, sizeof(struct vm_map_entry),
+		       M_VMMAPENT, M_WAITOK);
+	} else {
+		if (entry = kentry_free)
+			kentry_free = kentry_free->next;
+	}
+	if (entry == NULL)
+		panic("vm_map_entry_create: out of map entries");
+
+	return(entry);
+}
+
+/*
+ *	vm_map_entry_dispose:	[ internal use only ]
+ *
+ *	Inverse of vm_map_entry_create.
+ */
+void vm_map_entry_dispose(map, entry)
+	vm_map_t	map;
+	vm_map_entry_t	entry;
+{
+#ifdef DEBUG
+	extern vm_map_t		kernel_map, kmem_map, mb_map, pager_map;
+	boolean_t		isspecial;
+
+	isspecial = (map == kernel_map || map == kmem_map ||
+		     map == mb_map || map == pager_map);
+	if (isspecial && map->entries_pageable ||
+	    !isspecial && !map->entries_pageable)
+		panic("vm_map_entry_dispose: bogus map");
+#endif
+	if (map->entries_pageable) {
+		FREE(entry, M_VMMAPENT);
+	} else {
+		entry->next = kentry_free;
+		kentry_free = entry;
+	}
+}
+
+/*
+ *	vm_map_entry_{un,}link:
+ *
+ *	Insert/remove entries from maps.
+ */
+#define	vm_map_entry_link(map, after_where, entry) \
+		{ \
+		(map)->nentries++; \
+		(entry)->prev = (after_where); \
+		(entry)->next = (after_where)->next; \
+		(entry)->prev->next = (entry); \
+		(entry)->next->prev = (entry); \
+		}
+#define	vm_map_entry_unlink(map, entry) \
+		{ \
+		(map)->nentries--; \
+		(entry)->next->prev = (entry)->prev; \
+		(entry)->prev->next = (entry)->next; \
+		}
+
+/*
+ *	vm_map_reference:
+ *
+ *	Creates another valid reference to the given map.
+ *
+ */
+void vm_map_reference(map)
+	register vm_map_t	map;
+{
+	if (map == NULL)
+		return;
+
+	simple_lock(&map->ref_lock);
+	map->ref_count++;
+	simple_unlock(&map->ref_lock);
+}
+
+/*
+ *	vm_map_deallocate:
+ *
+ *	Removes a reference from the specified map,
+ *	destroying it if no references remain.
+ *	The map should not be locked.
+ */
+void vm_map_deallocate(map)
+	register vm_map_t	map;
+{
+	register int		c;
+
+	if (map == NULL)
+		return;
+
+	simple_lock(&map->ref_lock);
+	c = --map->ref_count;
+	simple_unlock(&map->ref_lock);
+
+	if (c > 0) {
+		return;
+	}
+
+	/*
+	 *	Lock the map, to wait out all other references
+	 *	to it.
+	 */
+
+	vm_map_lock(map);
+
+	(void) vm_map_delete(map, map->min_offset, map->max_offset);
+
+	pmap_destroy(map->pmap);
+
+	FREE(map, M_VMMAP);
+}
+
+/*
+ *	vm_map_insert:
+ *
+ *	Inserts the given whole VM object into the target
+ *	map at the specified address range.  The object's
+ *	size should match that of the address range.
+ *
+ *	Requires that the map be locked, and leaves it so.
+ */
+int
+vm_map_insert(map, object, offset, start, end)
+	vm_map_t	map;
+	vm_object_t	object;
+	vm_offset_t	offset;
+	vm_offset_t	start;
+	vm_offset_t	end;
+{
+	register vm_map_entry_t		new_entry;
+	register vm_map_entry_t		prev_entry;
+	vm_map_entry_t			temp_entry;
+
+	/*
+	 *	Check that the start and end points are not bogus.
+	 */
+
+	if ((start < map->min_offset) || (end > map->max_offset) ||
+			(start >= end))
+		return(KERN_INVALID_ADDRESS);
+
+	/*
+	 *	Find the entry prior to the proposed
+	 *	starting address; if it's part of an
+	 *	existing entry, this range is bogus.
+	 */
+
+	if (vm_map_lookup_entry(map, start, &temp_entry))
+		return(KERN_NO_SPACE);
+
+	prev_entry = temp_entry;
+
+	/*
+	 *	Assert that the next entry doesn't overlap the
+	 *	end point.
+	 */
+
+	if ((prev_entry->next != &map->header) &&
+			(prev_entry->next->start < end))
+		return(KERN_NO_SPACE);
+
+	/*
+	 *	See if we can avoid creating a new entry by
+	 *	extending one of our neighbors.
+	 */
+
+	if (object == NULL) {
+		if ((prev_entry != &map->header) &&
+		    (prev_entry->end == start) &&
+		    (map->is_main_map) &&
+		    (prev_entry->is_a_map == FALSE) &&
+		    (prev_entry->is_sub_map == FALSE) &&
+		    (prev_entry->inheritance == VM_INHERIT_DEFAULT) &&
+		    (prev_entry->protection == VM_PROT_DEFAULT) &&
+		    (prev_entry->max_protection == VM_PROT_DEFAULT) &&
+		    (prev_entry->wired_count == 0)) {
+
+			if (vm_object_coalesce(prev_entry->object.vm_object,
+					NULL,
+					prev_entry->offset,
+					(vm_offset_t) 0,
+					(vm_size_t)(prev_entry->end
+						     - prev_entry->start),
+					(vm_size_t)(end - prev_entry->end))) {
+				/*
+				 *	Coalesced the two objects - can extend
+				 *	the previous map entry to include the
+				 *	new range.
+				 */
+				map->size += (end - prev_entry->end);
+				prev_entry->end = end;
+				return(KERN_SUCCESS);
+			}
+		}
+	}
+
+	/*
+	 *	Create a new entry
+	 */
+
+	new_entry = vm_map_entry_create(map);
+	new_entry->start = start;
+	new_entry->end = end;
+
+	new_entry->is_a_map = FALSE;
+	new_entry->is_sub_map = FALSE;
+	new_entry->object.vm_object = object;
+	new_entry->offset = offset;
+
+	new_entry->copy_on_write = FALSE;
+	new_entry->needs_copy = FALSE;
+
+	if (map->is_main_map) {
+		new_entry->inheritance = VM_INHERIT_DEFAULT;
+		new_entry->protection = VM_PROT_DEFAULT;
+		new_entry->max_protection = VM_PROT_DEFAULT;
+		new_entry->wired_count = 0;
+	}
+
+	/*
+	 *	Insert the new entry into the list
+	 */
+
+	vm_map_entry_link(map, prev_entry, new_entry);
+	map->size += new_entry->end - new_entry->start;
+
+	/*
+	 *	Update the free space hint
+	 */
+
+	if ((map->first_free == prev_entry) && (prev_entry->end >= new_entry->start))
+		map->first_free = new_entry;
+
+	return(KERN_SUCCESS);
+}
+
+/*
+ *	SAVE_HINT:
+ *
+ *	Saves the specified entry as the hint for
+ *	future lookups.  Performs necessary interlocks.
+ */
+#define	SAVE_HINT(map,value) \
+		simple_lock(&(map)->hint_lock); \
+		(map)->hint = (value); \
+		simple_unlock(&(map)->hint_lock);
+
+/*
+ *	vm_map_lookup_entry:	[ internal use only ]
+ *
+ *	Finds the map entry containing (or
+ *	immediately preceding) the specified address
+ *	in the given map; the entry is returned
+ *	in the "entry" parameter.  The boolean
+ *	result indicates whether the address is
+ *	actually contained in the map.
+ */
+boolean_t vm_map_lookup_entry(map, address, entry)
+	register vm_map_t	map;
+	register vm_offset_t	address;
+	vm_map_entry_t		*entry;		/* OUT */
+{
+	register vm_map_entry_t		cur;
+	register vm_map_entry_t		last;
+
+	/*
+	 *	Start looking either from the head of the
+	 *	list, or from the hint.
+	 */
+
+	simple_lock(&map->hint_lock);
+	cur = map->hint;
+	simple_unlock(&map->hint_lock);
+
+	if (cur == &map->header)
+		cur = cur->next;
+
+	if (address >= cur->start) {
+	    	/*
+		 *	Go from hint to end of list.
+		 *
+		 *	But first, make a quick check to see if
+		 *	we are already looking at the entry we
+		 *	want (which is usually the case).
+		 *	Note also that we don't need to save the hint
+		 *	here... it is the same hint (unless we are
+		 *	at the header, in which case the hint didn't
+		 *	buy us anything anyway).
+		 */
+		last = &map->header;
+		if ((cur != last) && (cur->end > address)) {
+			*entry = cur;
+			return(TRUE);
+		}
+	}
+	else {
+	    	/*
+		 *	Go from start to hint, *inclusively*
+		 */
+		last = cur->next;
+		cur = map->header.next;
+	}
+
+	/*
+	 *	Search linearly
+	 */
+
+	while (cur != last) {
+		if (cur->end > address) {
+			if (address >= cur->start) {
+			    	/*
+				 *	Save this lookup for future
+				 *	hints, and return
+				 */
+
+				*entry = cur;
+				SAVE_HINT(map, cur);
+				return(TRUE);
+			}
+			break;
+		}
+		cur = cur->next;
+	}
+	*entry = cur->prev;
+	SAVE_HINT(map, *entry);
+	return(FALSE);
+}
+
+/*
+ * Find sufficient space for `length' bytes in the given map, starting at
+ * `start'.  The map must be locked.  Returns 0 on success, 1 on no space.
+ */
+int
+vm_map_findspace(map, start, length, addr)
+	register vm_map_t map;
+	register vm_offset_t start;
+	vm_size_t length;
+	vm_offset_t *addr;
+{
+	register vm_map_entry_t entry, next;
+	register vm_offset_t end;
+
+	if (start < map->min_offset)
+		start = map->min_offset;
+	if (start > map->max_offset)
+		return (1);
+
+	/*
+	 * Look for the first possible address; if there's already
+	 * something at this address, we have to start after it.
+	 */
+	if (start == map->min_offset) {
+		if ((entry = map->first_free) != &map->header)
+			start = entry->end;
+	} else {
+		vm_map_entry_t tmp;
+		if (vm_map_lookup_entry(map, start, &tmp))
+			start = tmp->end;
+		entry = tmp;
+	}
+
+	/*
+	 * Look through the rest of the map, trying to fit a new region in
+	 * the gap between existing regions, or after the very last region.
+	 */
+	for (;; start = (entry = next)->end) {
+		/*
+		 * Find the end of the proposed new region.  Be sure we didn't
+		 * go beyond the end of the map, or wrap around the address;
+		 * if so, we lose.  Otherwise, if this is the last entry, or
+		 * if the proposed new region fits before the next entry, we
+		 * win.
+		 */
+		end = start + length;
+		if (end > map->max_offset || end < start)
+			return (1);
+		next = entry->next;
+		if (next == &map->header || next->start >= end)
+			break;
+	}
+	SAVE_HINT(map, entry);
+	*addr = start;
+	return (0);
+}
+
+/*
+ *	vm_map_find finds an unallocated region in the target address
+ *	map with the given length.  The search is defined to be
+ *	first-fit from the specified address; the region found is
+ *	returned in the same parameter.
+ *
+ */
+int
+vm_map_find(map, object, offset, addr, length, find_space)
+	vm_map_t	map;
+	vm_object_t	object;
+	vm_offset_t	offset;
+	vm_offset_t	*addr;		/* IN/OUT */
+	vm_size_t	length;
+	boolean_t	find_space;
+{
+	register vm_offset_t	start;
+	int			result;
+
+	start = *addr;
+	vm_map_lock(map);
+	if (find_space) {
+		if (vm_map_findspace(map, start, length, addr)) {
+			vm_map_unlock(map);
+			return (KERN_NO_SPACE);
+		}
+		start = *addr;
+	}
+	result = vm_map_insert(map, object, offset, start, start + length);
+	vm_map_unlock(map);
+	return (result);
+}
+
+/*
+ *	vm_map_simplify_entry:	[ internal use only ]
+ *
+ *	Simplify the given map entry by:
+ *		removing extra sharing maps
+ *		[XXX maybe later] merging with a neighbor
+ */
+void vm_map_simplify_entry(map, entry)
+	vm_map_t	map;
+	vm_map_entry_t	entry;
+{
+#ifdef	lint
+	map++;
+#endif
+
+	/*
+	 *	If this entry corresponds to a sharing map, then
+	 *	see if we can remove the level of indirection.
+	 *	If it's not a sharing map, then it points to
+	 *	a VM object, so see if we can merge with either
+	 *	of our neighbors.
+	 */
+
+	if (entry->is_sub_map)
+		return;
+	if (entry->is_a_map) {
+#if	0
+		vm_map_t	my_share_map;
+		int		count;
+
+		my_share_map = entry->object.share_map;	
+		simple_lock(&my_share_map->ref_lock);
+		count = my_share_map->ref_count;
+		simple_unlock(&my_share_map->ref_lock);
+		
+		if (count == 1) {
+			/* Can move the region from
+			 * entry->start to entry->end (+ entry->offset)
+			 * in my_share_map into place of entry.
+			 * Later.
+			 */
+		}
+#endif
+	}
+	else {
+		/*
+		 *	Try to merge with our neighbors.
+		 *
+		 *	Conditions for merge are:
+		 *
+		 *	1.  entries are adjacent.
+		 *	2.  both entries point to objects
+		 *	    with null pagers.
+		 *
+		 * 	If a merge is possible, we replace the two
+		 *	entries with a single entry, then merge
+		 *	the two objects into a single object.
+		 *
+		 *	Now, all that is left to do is write the
+		 *	code!
+		 */
+	}
+}
+
+/*
+ *	vm_map_clip_start:	[ internal use only ]
+ *
+ *	Asserts that the given entry begins at or after
+ *	the specified address; if necessary,
+ *	it splits the entry into two.
+ */
+#define vm_map_clip_start(map, entry, startaddr) \
+{ \
+	if (startaddr > entry->start) \
+		_vm_map_clip_start(map, entry, startaddr); \
+}
+
+/*
+ *	This routine is called only when it is known that
+ *	the entry must be split.
+ */
+static void _vm_map_clip_start(map, entry, start)
+	register vm_map_t	map;
+	register vm_map_entry_t	entry;
+	register vm_offset_t	start;
+{
+	register vm_map_entry_t	new_entry;
+
+	/*
+	 *	See if we can simplify this entry first
+	 */
+		 
+	vm_map_simplify_entry(map, entry);
+
+	/*
+	 *	Split off the front portion --
+	 *	note that we must insert the new
+	 *	entry BEFORE this one, so that
+	 *	this entry has the specified starting
+	 *	address.
+	 */
+
+	new_entry = vm_map_entry_create(map);
+	*new_entry = *entry;
+
+	new_entry->end = start;
+	entry->offset += (start - entry->start);
+	entry->start = start;
+
+	vm_map_entry_link(map, entry->prev, new_entry);
+
+	if (entry->is_a_map || entry->is_sub_map)
+	 	vm_map_reference(new_entry->object.share_map);
+	else
+		vm_object_reference(new_entry->object.vm_object);
+}
+
+/*
+ *	vm_map_clip_end:	[ internal use only ]
+ *
+ *	Asserts that the given entry ends at or before
+ *	the specified address; if necessary,
+ *	it splits the entry into two.
+ */
+
+#define vm_map_clip_end(map, entry, endaddr) \
+{ \
+	if (endaddr < entry->end) \
+		_vm_map_clip_end(map, entry, endaddr); \
+}
+
+/*
+ *	This routine is called only when it is known that
+ *	the entry must be split.
+ */
+static void _vm_map_clip_end(map, entry, end)
+	register vm_map_t	map;
+	register vm_map_entry_t	entry;
+	register vm_offset_t	end;
+{
+	register vm_map_entry_t	new_entry;
+
+	/*
+	 *	Create a new entry and insert it
+	 *	AFTER the specified entry
+	 */
+
+	new_entry = vm_map_entry_create(map);
+	*new_entry = *entry;
+
+	new_entry->start = entry->end = end;
+	new_entry->offset += (end - entry->start);
+
+	vm_map_entry_link(map, entry, new_entry);
+
+	if (entry->is_a_map || entry->is_sub_map)
+	 	vm_map_reference(new_entry->object.share_map);
+	else
+		vm_object_reference(new_entry->object.vm_object);
+}
+
+/*
+ *	VM_MAP_RANGE_CHECK:	[ internal use only ]
+ *
+ *	Asserts that the starting and ending region
+ *	addresses fall within the valid range of the map.
+ */
+#define	VM_MAP_RANGE_CHECK(map, start, end)		\
+		{					\
+		if (start < vm_map_min(map))		\
+			start = vm_map_min(map);	\
+		if (end > vm_map_max(map))		\
+			end = vm_map_max(map);		\
+		if (start > end)			\
+			start = end;			\
+		}
+
+/*
+ *	vm_map_submap:		[ kernel use only ]
+ *
+ *	Mark the given range as handled by a subordinate map.
+ *
+ *	This range must have been created with vm_map_find,
+ *	and no other operations may have been performed on this
+ *	range prior to calling vm_map_submap.
+ *
+ *	Only a limited number of operations can be performed
+ *	within this rage after calling vm_map_submap:
+ *		vm_fault
+ *	[Don't try vm_map_copy!]
+ *
+ *	To remove a submapping, one must first remove the
+ *	range from the superior map, and then destroy the
+ *	submap (if desired).  [Better yet, don't try it.]
+ */
+int
+vm_map_submap(map, start, end, submap)
+	register vm_map_t	map;
+	register vm_offset_t	start;
+	register vm_offset_t	end;
+	vm_map_t		submap;
+{
+	vm_map_entry_t		entry;
+	register int		result = KERN_INVALID_ARGUMENT;
+
+	vm_map_lock(map);
+
+	VM_MAP_RANGE_CHECK(map, start, end);
+
+	if (vm_map_lookup_entry(map, start, &entry)) {
+		vm_map_clip_start(map, entry, start);
+	}
+	 else
+		entry = entry->next;
+
+	vm_map_clip_end(map, entry, end);
+
+	if ((entry->start == start) && (entry->end == end) &&
+	    (!entry->is_a_map) &&
+	    (entry->object.vm_object == NULL) &&
+	    (!entry->copy_on_write)) {
+		entry->is_a_map = FALSE;
+		entry->is_sub_map = TRUE;
+		vm_map_reference(entry->object.sub_map = submap);
+		result = KERN_SUCCESS;
+	}
+	vm_map_unlock(map);
+
+	return(result);
+}
+
+/*
+ *	vm_map_protect:
+ *
+ *	Sets the protection of the specified address
+ *	region in the target map.  If "set_max" is
+ *	specified, the maximum protection is to be set;
+ *	otherwise, only the current protection is affected.
+ */
+int
+vm_map_protect(map, start, end, new_prot, set_max)
+	register vm_map_t	map;
+	register vm_offset_t	start;
+	register vm_offset_t	end;
+	register vm_prot_t	new_prot;
+	register boolean_t	set_max;
+{
+	register vm_map_entry_t		current;
+	vm_map_entry_t			entry;
+
+	vm_map_lock(map);
+
+	VM_MAP_RANGE_CHECK(map, start, end);
+
+	if (vm_map_lookup_entry(map, start, &entry)) {
+		vm_map_clip_start(map, entry, start);
+	}
+	 else
+		entry = entry->next;
+
+	/*
+	 *	Make a first pass to check for protection
+	 *	violations.
+	 */
+
+	current = entry;
+	while ((current != &map->header) && (current->start < end)) {
+		if (current->is_sub_map)
+			return(KERN_INVALID_ARGUMENT);
+		if ((new_prot & current->max_protection) != new_prot) {
+			vm_map_unlock(map);
+			return(KERN_PROTECTION_FAILURE);
+		}
+
+		current = current->next;
+	}
+
+	/*
+	 *	Go back and fix up protections.
+	 *	[Note that clipping is not necessary the second time.]
+	 */
+
+	current = entry;
+
+	while ((current != &map->header) && (current->start < end)) {
+		vm_prot_t	old_prot;
+
+		vm_map_clip_end(map, current, end);
+
+		old_prot = current->protection;
+		if (set_max)
+			current->protection =
+				(current->max_protection = new_prot) &
+					old_prot;
+		else
+			current->protection = new_prot;
+
+		/*
+		 *	Update physical map if necessary.
+		 *	Worry about copy-on-write here -- CHECK THIS XXX
+		 */
+
+		if (current->protection != old_prot) {
+
+#define MASK(entry)	((entry)->copy_on_write ? ~VM_PROT_WRITE : \
+							VM_PROT_ALL)
+#define	max(a,b)	((a) > (b) ? (a) : (b))
+
+			if (current->is_a_map) {
+				vm_map_entry_t	share_entry;
+				vm_offset_t	share_end;
+
+				vm_map_lock(current->object.share_map);
+				(void) vm_map_lookup_entry(
+						current->object.share_map,
+						current->offset,
+						&share_entry);
+				share_end = current->offset +
+					(current->end - current->start);
+				while ((share_entry !=
+					&current->object.share_map->header) &&
+					(share_entry->start < share_end)) {
+
+					pmap_protect(map->pmap,
+						(max(share_entry->start,
+							current->offset) -
+							current->offset +
+							current->start),
+						min(share_entry->end,
+							share_end) -
+						current->offset +
+						current->start,
+						current->protection &
+							MASK(share_entry));
+
+					share_entry = share_entry->next;
+				}
+				vm_map_unlock(current->object.share_map);
+			}
+			else
+			 	pmap_protect(map->pmap, current->start,
+					current->end,
+					current->protection & MASK(entry));
+#undef	max
+#undef	MASK
+		}
+		current = current->next;
+	}
+
+	vm_map_unlock(map);
+	return(KERN_SUCCESS);
+}
+
+/*
+ *	vm_map_inherit:
+ *
+ *	Sets the inheritance of the specified address
+ *	range in the target map.  Inheritance
+ *	affects how the map will be shared with
+ *	child maps at the time of vm_map_fork.
+ */
+int
+vm_map_inherit(map, start, end, new_inheritance)
+	register vm_map_t	map;
+	register vm_offset_t	start;
+	register vm_offset_t	end;
+	register vm_inherit_t	new_inheritance;
+{
+	register vm_map_entry_t	entry;
+	vm_map_entry_t	temp_entry;
+
+	switch (new_inheritance) {
+	case VM_INHERIT_NONE:
+	case VM_INHERIT_COPY:
+	case VM_INHERIT_SHARE:
+		break;
+	default:
+		return(KERN_INVALID_ARGUMENT);
+	}
+
+	vm_map_lock(map);
+
+	VM_MAP_RANGE_CHECK(map, start, end);
+
+	if (vm_map_lookup_entry(map, start, &temp_entry)) {
+		entry = temp_entry;
+		vm_map_clip_start(map, entry, start);
+	}
+	else
+		entry = temp_entry->next;
+
+	while ((entry != &map->header) && (entry->start < end)) {
+		vm_map_clip_end(map, entry, end);
+
+		entry->inheritance = new_inheritance;
+
+		entry = entry->next;
+	}
+
+	vm_map_unlock(map);
+	return(KERN_SUCCESS);
+}
+
+/*
+ *	vm_map_pageable:
+ *
+ *	Sets the pageability of the specified address
+ *	range in the target map.  Regions specified
+ *	as not pageable require locked-down physical
+ *	memory and physical page maps.
+ *
+ *	The map must not be locked, but a reference
+ *	must remain to the map throughout the call.
+ */
+int
+vm_map_pageable(map, start, end, new_pageable)
+	register vm_map_t	map;
+	register vm_offset_t	start;
+	register vm_offset_t	end;
+	register boolean_t	new_pageable;
+{
+	register vm_map_entry_t	entry;
+	vm_map_entry_t		start_entry;
+	register vm_offset_t	failed;
+	int			rv;
+
+	vm_map_lock(map);
+
+	VM_MAP_RANGE_CHECK(map, start, end);
+
+	/*
+	 *	Only one pageability change may take place at one
+	 *	time, since vm_fault assumes it will be called
+	 *	only once for each wiring/unwiring.  Therefore, we
+	 *	have to make sure we're actually changing the pageability
+	 *	for the entire region.  We do so before making any changes.
+	 */
+
+	if (vm_map_lookup_entry(map, start, &start_entry) == FALSE) {
+		vm_map_unlock(map);
+		return(KERN_INVALID_ADDRESS);
+	}
+	entry = start_entry;
+
+	/*
+	 *	Actions are rather different for wiring and unwiring,
+	 *	so we have two separate cases.
+	 */
+
+	if (new_pageable) {
+
+		vm_map_clip_start(map, entry, start);
+
+		/*
+		 *	Unwiring.  First ensure that the range to be
+		 *	unwired is really wired down and that there
+		 *	are no holes.
+		 */
+		while ((entry != &map->header) && (entry->start < end)) {
+
+		    if (entry->wired_count == 0 ||
+			(entry->end < end &&
+			 (entry->next == &map->header ||
+			  entry->next->start > entry->end))) {
+			vm_map_unlock(map);
+			return(KERN_INVALID_ARGUMENT);
+		    }
+		    entry = entry->next;
+		}
+
+		/*
+		 *	Now decrement the wiring count for each region.
+		 *	If a region becomes completely unwired,
+		 *	unwire its physical pages and mappings.
+		 */
+		lock_set_recursive(&map->lock);
+
+		entry = start_entry;
+		while ((entry != &map->header) && (entry->start < end)) {
+		    vm_map_clip_end(map, entry, end);
+
+		    entry->wired_count--;
+		    if (entry->wired_count == 0)
+			vm_fault_unwire(map, entry->start, entry->end);
+
+		    entry = entry->next;
+		}
+		lock_clear_recursive(&map->lock);
+	}
+
+	else {
+		/*
+		 *	Wiring.  We must do this in two passes:
+		 *
+		 *	1.  Holding the write lock, we create any shadow
+		 *	    or zero-fill objects that need to be created.
+		 *	    Then we clip each map entry to the region to be
+		 *	    wired and increment its wiring count.  We
+		 *	    create objects before clipping the map entries
+		 *	    to avoid object proliferation.
+		 *
+		 *	2.  We downgrade to a read lock, and call
+		 *	    vm_fault_wire to fault in the pages for any
+		 *	    newly wired area (wired_count is 1).
+		 *
+		 *	Downgrading to a read lock for vm_fault_wire avoids
+		 *	a possible deadlock with another thread that may have
+		 *	faulted on one of the pages to be wired (it would mark
+		 *	the page busy, blocking us, then in turn block on the
+		 *	map lock that we hold).  Because of problems in the
+		 *	recursive lock package, we cannot upgrade to a write
+		 *	lock in vm_map_lookup.  Thus, any actions that require
+		 *	the write lock must be done beforehand.  Because we
+		 *	keep the read lock on the map, the copy-on-write status
+		 *	of the entries we modify here cannot change.
+		 */
+
+		/*
+		 *	Pass 1.
+		 */
+		while ((entry != &map->header) && (entry->start < end)) {
+		    if (entry->wired_count == 0) {
+
+			/*
+			 *	Perform actions of vm_map_lookup that need
+			 *	the write lock on the map: create a shadow
+			 *	object for a copy-on-write region, or an
+			 *	object for a zero-fill region.
+			 *
+			 *	We don't have to do this for entries that
+			 *	point to sharing maps, because we won't hold
+			 *	the lock on the sharing map.
+			 */
+			if (!entry->is_a_map) {
+			    if (entry->needs_copy &&
+				((entry->protection & VM_PROT_WRITE) != 0)) {
+
+				vm_object_shadow(&entry->object.vm_object,
+						&entry->offset,
+						(vm_size_t)(entry->end
+							- entry->start));
+				entry->needs_copy = FALSE;
+			    }
+			    else if (entry->object.vm_object == NULL) {
+				entry->object.vm_object =
+				    vm_object_allocate((vm_size_t)(entry->end
+				    			- entry->start));
+				entry->offset = (vm_offset_t)0;
+			    }
+			}
+		    }
+		    vm_map_clip_start(map, entry, start);
+		    vm_map_clip_end(map, entry, end);
+		    entry->wired_count++;
+
+		    /*
+		     * Check for holes
+		     */
+		    if (entry->end < end &&
+			(entry->next == &map->header ||
+			 entry->next->start > entry->end)) {
+			/*
+			 *	Found one.  Object creation actions
+			 *	do not need to be undone, but the
+			 *	wired counts need to be restored.
+			 */
+			while (entry != &map->header && entry->end > start) {
+			    entry->wired_count--;
+			    entry = entry->prev;
+			}
+			vm_map_unlock(map);
+			return(KERN_INVALID_ARGUMENT);
+		    }
+		    entry = entry->next;
+		}
+
+		/*
+		 *	Pass 2.
+		 */
+
+		/*
+		 * HACK HACK HACK HACK
+		 *
+		 * If we are wiring in the kernel map or a submap of it,
+		 * unlock the map to avoid deadlocks.  We trust that the
+		 * kernel threads are well-behaved, and therefore will
+		 * not do anything destructive to this region of the map
+		 * while we have it unlocked.  We cannot trust user threads
+		 * to do the same.
+		 *
+		 * HACK HACK HACK HACK
+		 */
+		if (vm_map_pmap(map) == kernel_pmap) {
+		    vm_map_unlock(map);		/* trust me ... */
+		}
+		else {
+		    lock_set_recursive(&map->lock);
+		    lock_write_to_read(&map->lock);
+		}
+
+		rv = 0;
+		entry = start_entry;
+		while (entry != &map->header && entry->start < end) {
+		    /*
+		     * If vm_fault_wire fails for any page we need to
+		     * undo what has been done.  We decrement the wiring
+		     * count for those pages which have not yet been
+		     * wired (now) and unwire those that have (later).
+		     *
+		     * XXX this violates the locking protocol on the map,
+		     * needs to be fixed.
+		     */
+		    if (rv)
+			entry->wired_count--;
+		    else if (entry->wired_count == 1) {
+			rv = vm_fault_wire(map, entry->start, entry->end);
+			if (rv) {
+			    failed = entry->start;
+			    entry->wired_count--;
+			}
+		    }
+		    entry = entry->next;
+		}
+
+		if (vm_map_pmap(map) == kernel_pmap) {
+		    vm_map_lock(map);
+		}
+		else {
+		    lock_clear_recursive(&map->lock);
+		}
+		if (rv) {
+		    vm_map_unlock(map);
+		    (void) vm_map_pageable(map, start, failed, TRUE);
+		    return(rv);
+		}
+	}
+
+	vm_map_unlock(map);
+
+	return(KERN_SUCCESS);
+}
+
+/*
+ * vm_map_clean
+ *
+ * Push any dirty cached pages in the address range to their pager.
+ * If syncio is TRUE, dirty pages are written synchronously.
+ * If invalidate is TRUE, any cached pages are freed as well.
+ *
+ * Returns an error if any part of the specified range is not mapped.
+ */
+int
+vm_map_clean(map, start, end, syncio, invalidate)
+	vm_map_t	map;
+	vm_offset_t	start;
+	vm_offset_t	end;
+	boolean_t	syncio;
+	boolean_t	invalidate;
+{
+	register vm_map_entry_t current;
+	vm_map_entry_t entry;
+	vm_size_t size;
+	vm_object_t object;
+	vm_offset_t offset;
+
+	vm_map_lock_read(map);
+	VM_MAP_RANGE_CHECK(map, start, end);
+	if (!vm_map_lookup_entry(map, start, &entry)) {
+		vm_map_unlock_read(map);
+		return(KERN_INVALID_ADDRESS);
+	}
+
+	/*
+	 * Make a first pass to check for holes.
+	 */
+	for (current = entry; current->start < end; current = current->next) {
+		if (current->is_sub_map) {
+			vm_map_unlock_read(map);
+			return(KERN_INVALID_ARGUMENT);
+		}
+		if (end > current->end &&
+		    (current->next == &map->header ||
+		     current->end != current->next->start)) {
+			vm_map_unlock_read(map);
+			return(KERN_INVALID_ADDRESS);
+		}
+	}
+
+	/*
+	 * Make a second pass, cleaning/uncaching pages from the indicated
+	 * objects as we go.
+	 */
+	for (current = entry; current->start < end; current = current->next) {
+		offset = current->offset + (start - current->start);
+		size = (end <= current->end ? end : current->end) - start;
+		if (current->is_a_map) {
+			register vm_map_t smap;
+			vm_map_entry_t tentry;
+			vm_size_t tsize;
+
+			smap = current->object.share_map;
+			vm_map_lock_read(smap);
+			(void) vm_map_lookup_entry(smap, offset, &tentry);
+			tsize = tentry->end - offset;
+			if (tsize < size)
+				size = tsize;
+			object = tentry->object.vm_object;
+			offset = tentry->offset + (offset - tentry->start);
+			vm_object_lock(object);
+			vm_map_unlock_read(smap);
+		} else {
+			object = current->object.vm_object;
+			vm_object_lock(object);
+		}
+		/*
+		 * Flush pages if writing is allowed.
+		 * XXX should we continue on an error?
+		 */
+		if ((current->protection & VM_PROT_WRITE) &&
+		    !vm_object_page_clean(object, offset, offset+size,
+					  syncio, FALSE)) {
+			vm_object_unlock(object);
+			vm_map_unlock_read(map);
+			return(KERN_FAILURE);
+		}
+		if (invalidate)
+			vm_object_page_remove(object, offset, offset+size);
+		vm_object_unlock(object);
+		start += size;
+	}
+
+	vm_map_unlock_read(map);
+	return(KERN_SUCCESS);
+}
+
+/*
+ *	vm_map_entry_unwire:	[ internal use only ]
+ *
+ *	Make the region specified by this entry pageable.
+ *
+ *	The map in question should be locked.
+ *	[This is the reason for this routine's existence.]
+ */
+void vm_map_entry_unwire(map, entry)
+	vm_map_t		map;
+	register vm_map_entry_t	entry;
+{
+	vm_fault_unwire(map, entry->start, entry->end);
+	entry->wired_count = 0;
+}
+
+/*
+ *	vm_map_entry_delete:	[ internal use only ]
+ *
+ *	Deallocate the given entry from the target map.
+ */		
+void vm_map_entry_delete(map, entry)
+	register vm_map_t	map;
+	register vm_map_entry_t	entry;
+{
+	if (entry->wired_count != 0)
+		vm_map_entry_unwire(map, entry);
+		
+	vm_map_entry_unlink(map, entry);
+	map->size -= entry->end - entry->start;
+
+	if (entry->is_a_map || entry->is_sub_map)
+		vm_map_deallocate(entry->object.share_map);
+	else
+	 	vm_object_deallocate(entry->object.vm_object);
+
+	vm_map_entry_dispose(map, entry);
+}
+
+/*
+ *	vm_map_delete:	[ internal use only ]
+ *
+ *	Deallocates the given address range from the target
+ *	map.
+ *
+ *	When called with a sharing map, removes pages from
+ *	that region from all physical maps.
+ */
+int
+vm_map_delete(map, start, end)
+	register vm_map_t	map;
+	vm_offset_t		start;
+	register vm_offset_t	end;
+{
+	register vm_map_entry_t	entry;
+	vm_map_entry_t		first_entry;
+
+	/*
+	 *	Find the start of the region, and clip it
+	 */
+
+	if (!vm_map_lookup_entry(map, start, &first_entry))
+		entry = first_entry->next;
+	else {
+		entry = first_entry;
+		vm_map_clip_start(map, entry, start);
+
+		/*
+		 *	Fix the lookup hint now, rather than each
+		 *	time though the loop.
+		 */
+
+		SAVE_HINT(map, entry->prev);
+	}
+
+	/*
+	 *	Save the free space hint
+	 */
+
+	if (map->first_free->start >= start)
+		map->first_free = entry->prev;
+
+	/*
+	 *	Step through all entries in this region
+	 */
+
+	while ((entry != &map->header) && (entry->start < end)) {
+		vm_map_entry_t		next;
+		register vm_offset_t	s, e;
+		register vm_object_t	object;
+
+		vm_map_clip_end(map, entry, end);
+
+		next = entry->next;
+		s = entry->start;
+		e = entry->end;
+
+		/*
+		 *	Unwire before removing addresses from the pmap;
+		 *	otherwise, unwiring will put the entries back in
+		 *	the pmap.
+		 */
+
+		object = entry->object.vm_object;
+		if (entry->wired_count != 0)
+			vm_map_entry_unwire(map, entry);
+
+		/*
+		 *	If this is a sharing map, we must remove
+		 *	*all* references to this data, since we can't
+		 *	find all of the physical maps which are sharing
+		 *	it.
+		 */
+
+		if (object == kernel_object || object == kmem_object)
+			vm_object_page_remove(object, entry->offset,
+					entry->offset + (e - s));
+		else if (!map->is_main_map)
+			vm_object_pmap_remove(object,
+					 entry->offset,
+					 entry->offset + (e - s));
+		else
+			pmap_remove(map->pmap, s, e);
+
+		/*
+		 *	Delete the entry (which may delete the object)
+		 *	only after removing all pmap entries pointing
+		 *	to its pages.  (Otherwise, its page frames may
+		 *	be reallocated, and any modify bits will be
+		 *	set in the wrong object!)
+		 */
+
+		vm_map_entry_delete(map, entry);
+		entry = next;
+	}
+	return(KERN_SUCCESS);
+}
+
+/*
+ *	vm_map_remove:
+ *
+ *	Remove the given address range from the target map.
+ *	This is the exported form of vm_map_delete.
+ */
+int
+vm_map_remove(map, start, end)
+	register vm_map_t	map;
+	register vm_offset_t	start;
+	register vm_offset_t	end;
+{
+	register int		result;
+
+	vm_map_lock(map);
+	VM_MAP_RANGE_CHECK(map, start, end);
+	result = vm_map_delete(map, start, end);
+	vm_map_unlock(map);
+
+	return(result);
+}
+
+/*
+ *	vm_map_check_protection:
+ *
+ *	Assert that the target map allows the specified
+ *	privilege on the entire address region given.
+ *	The entire region must be allocated.
+ */
+boolean_t vm_map_check_protection(map, start, end, protection)
+	register vm_map_t	map;
+	register vm_offset_t	start;
+	register vm_offset_t	end;
+	register vm_prot_t	protection;
+{
+	register vm_map_entry_t	entry;
+	vm_map_entry_t		tmp_entry;
+
+	if (!vm_map_lookup_entry(map, start, &tmp_entry)) {
+		return(FALSE);
+	}
+
+	entry = tmp_entry;
+
+	while (start < end) {
+		if (entry == &map->header) {
+			return(FALSE);
+		}
+
+		/*
+		 *	No holes allowed!
+		 */
+
+		if (start < entry->start) {
+			return(FALSE);
+		}
+
+		/*
+		 * Check protection associated with entry.
+		 */
+
+		if ((entry->protection & protection) != protection) {
+			return(FALSE);
+		}
+
+		/* go to next entry */
+
+		start = entry->end;
+		entry = entry->next;
+	}
+	return(TRUE);
+}
+
+/*
+ *	vm_map_copy_entry:
+ *
+ *	Copies the contents of the source entry to the destination
+ *	entry.  The entries *must* be aligned properly.
+ */
+void vm_map_copy_entry(src_map, dst_map, src_entry, dst_entry)
+	vm_map_t		src_map, dst_map;
+	register vm_map_entry_t	src_entry, dst_entry;
+{
+	vm_object_t	temp_object;
+
+	if (src_entry->is_sub_map || dst_entry->is_sub_map)
+		return;
+
+	if (dst_entry->object.vm_object != NULL &&
+	    (dst_entry->object.vm_object->flags & OBJ_INTERNAL) == 0)
+		printf("vm_map_copy_entry: copying over permanent data!\n");
+
+	/*
+	 *	If our destination map was wired down,
+	 *	unwire it now.
+	 */
+
+	if (dst_entry->wired_count != 0)
+		vm_map_entry_unwire(dst_map, dst_entry);
+
+	/*
+	 *	If we're dealing with a sharing map, we
+	 *	must remove the destination pages from
+	 *	all maps (since we cannot know which maps
+	 *	this sharing map belongs in).
+	 */
+
+	if (dst_map->is_main_map)
+		pmap_remove(dst_map->pmap, dst_entry->start, dst_entry->end);
+	else
+		vm_object_pmap_remove(dst_entry->object.vm_object,
+			dst_entry->offset,
+			dst_entry->offset +
+				(dst_entry->end - dst_entry->start));
+
+	if (src_entry->wired_count == 0) {
+
+		boolean_t	src_needs_copy;
+
+		/*
+		 *	If the source entry is marked needs_copy,
+		 *	it is already write-protected.
+		 */
+		if (!src_entry->needs_copy) {
+
+			boolean_t	su;
+
+			/*
+			 *	If the source entry has only one mapping,
+			 *	we can just protect the virtual address
+			 *	range.
+			 */
+			if (!(su = src_map->is_main_map)) {
+				simple_lock(&src_map->ref_lock);
+				su = (src_map->ref_count == 1);
+				simple_unlock(&src_map->ref_lock);
+			}
+
+			if (su) {
+				pmap_protect(src_map->pmap,
+					src_entry->start,
+					src_entry->end,
+					src_entry->protection & ~VM_PROT_WRITE);
+			}
+			else {
+				vm_object_pmap_copy(src_entry->object.vm_object,
+					src_entry->offset,
+					src_entry->offset + (src_entry->end
+							    -src_entry->start));
+			}
+		}
+
+		/*
+		 *	Make a copy of the object.
+		 */
+		temp_object = dst_entry->object.vm_object;
+		vm_object_copy(src_entry->object.vm_object,
+				src_entry->offset,
+				(vm_size_t)(src_entry->end -
+					    src_entry->start),
+				&dst_entry->object.vm_object,
+				&dst_entry->offset,
+				&src_needs_copy);
+		/*
+		 *	If we didn't get a copy-object now, mark the
+		 *	source map entry so that a shadow will be created
+		 *	to hold its changed pages.
+		 */
+		if (src_needs_copy)
+			src_entry->needs_copy = TRUE;
+
+		/*
+		 *	The destination always needs to have a shadow
+		 *	created.
+		 */
+		dst_entry->needs_copy = TRUE;
+
+		/*
+		 *	Mark the entries copy-on-write, so that write-enabling
+		 *	the entry won't make copy-on-write pages writable.
+		 */
+		src_entry->copy_on_write = TRUE;
+		dst_entry->copy_on_write = TRUE;
+		/*
+		 *	Get rid of the old object.
+		 */
+		vm_object_deallocate(temp_object);
+
+		pmap_copy(dst_map->pmap, src_map->pmap, dst_entry->start,
+			dst_entry->end - dst_entry->start, src_entry->start);
+	}
+	else {
+		/*
+		 *	Of course, wired down pages can't be set copy-on-write.
+		 *	Cause wired pages to be copied into the new
+		 *	map by simulating faults (the new pages are
+		 *	pageable)
+		 */
+		vm_fault_copy_entry(dst_map, src_map, dst_entry, src_entry);
+	}
+}
+
+/*
+ *	vm_map_copy:
+ *
+ *	Perform a virtual memory copy from the source
+ *	address map/range to the destination map/range.
+ *
+ *	If src_destroy or dst_alloc is requested,
+ *	the source and destination regions should be
+ *	disjoint, not only in the top-level map, but
+ *	in the sharing maps as well.  [The best way
+ *	to guarantee this is to use a new intermediate
+ *	map to make copies.  This also reduces map
+ *	fragmentation.]
+ */
+int
+vm_map_copy(dst_map, src_map,
+			  dst_addr, len, src_addr,
+			  dst_alloc, src_destroy)
+	vm_map_t	dst_map;
+	vm_map_t	src_map;
+	vm_offset_t	dst_addr;
+	vm_size_t	len;
+	vm_offset_t	src_addr;
+	boolean_t	dst_alloc;
+	boolean_t	src_destroy;
+{
+	register
+	vm_map_entry_t	src_entry;
+	register
+	vm_map_entry_t	dst_entry;
+	vm_map_entry_t	tmp_entry;
+	vm_offset_t	src_start;
+	vm_offset_t	src_end;
+	vm_offset_t	dst_start;
+	vm_offset_t	dst_end;
+	vm_offset_t	src_clip;
+	vm_offset_t	dst_clip;
+	int		result;
+	boolean_t	old_src_destroy;
+
+	/*
+	 *	XXX While we figure out why src_destroy screws up,
+	 *	we'll do it by explicitly vm_map_delete'ing at the end.
+	 */
+
+	old_src_destroy = src_destroy;
+	src_destroy = FALSE;
+
+	/*
+	 *	Compute start and end of region in both maps
+	 */
+
+	src_start = src_addr;
+	src_end = src_start + len;
+	dst_start = dst_addr;
+	dst_end = dst_start + len;
+
+	/*
+	 *	Check that the region can exist in both source
+	 *	and destination.
+	 */
+
+	if ((dst_end < dst_start) || (src_end < src_start))
+		return(KERN_NO_SPACE);
+
+	/*
+	 *	Lock the maps in question -- we avoid deadlock
+	 *	by ordering lock acquisition by map value
+	 */
+
+	if (src_map == dst_map) {
+		vm_map_lock(src_map);
+	}
+	else if ((int) src_map < (int) dst_map) {
+	 	vm_map_lock(src_map);
+		vm_map_lock(dst_map);
+	} else {
+		vm_map_lock(dst_map);
+	 	vm_map_lock(src_map);
+	}
+
+	result = KERN_SUCCESS;
+
+	/*
+	 *	Check protections... source must be completely readable and
+	 *	destination must be completely writable.  [Note that if we're
+	 *	allocating the destination region, we don't have to worry
+	 *	about protection, but instead about whether the region
+	 *	exists.]
+	 */
+
+	if (src_map->is_main_map && dst_map->is_main_map) {
+		if (!vm_map_check_protection(src_map, src_start, src_end,
+					VM_PROT_READ)) {
+			result = KERN_PROTECTION_FAILURE;
+			goto Return;
+		}
+
+		if (dst_alloc) {
+			/* XXX Consider making this a vm_map_find instead */
+			if ((result = vm_map_insert(dst_map, NULL,
+					(vm_offset_t) 0, dst_start, dst_end)) != KERN_SUCCESS)
+				goto Return;
+		}
+		else if (!vm_map_check_protection(dst_map, dst_start, dst_end,
+					VM_PROT_WRITE)) {
+			result = KERN_PROTECTION_FAILURE;
+			goto Return;
+		}
+	}
+
+	/*
+	 *	Find the start entries and clip.
+	 *
+	 *	Note that checking protection asserts that the
+	 *	lookup cannot fail.
+	 *
+	 *	Also note that we wait to do the second lookup
+	 *	until we have done the first clip, as the clip
+	 *	may affect which entry we get!
+	 */
+
+	(void) vm_map_lookup_entry(src_map, src_addr, &tmp_entry);
+	src_entry = tmp_entry;
+	vm_map_clip_start(src_map, src_entry, src_start);
+
+	(void) vm_map_lookup_entry(dst_map, dst_addr, &tmp_entry);
+	dst_entry = tmp_entry;
+	vm_map_clip_start(dst_map, dst_entry, dst_start);
+
+	/*
+	 *	If both source and destination entries are the same,
+	 *	retry the first lookup, as it may have changed.
+	 */
+
+	if (src_entry == dst_entry) {
+		(void) vm_map_lookup_entry(src_map, src_addr, &tmp_entry);
+		src_entry = tmp_entry;
+	}
+
+	/*
+	 *	If source and destination entries are still the same,
+	 *	a null copy is being performed.
+	 */
+
+	if (src_entry == dst_entry)
+		goto Return;
+
+	/*
+	 *	Go through entries until we get to the end of the
+	 *	region.
+	 */
+
+	while (src_start < src_end) {
+		/*
+		 *	Clip the entries to the endpoint of the entire region.
+		 */
+
+		vm_map_clip_end(src_map, src_entry, src_end);
+		vm_map_clip_end(dst_map, dst_entry, dst_end);
+
+		/*
+		 *	Clip each entry to the endpoint of the other entry.
+		 */
+
+		src_clip = src_entry->start + (dst_entry->end - dst_entry->start);
+		vm_map_clip_end(src_map, src_entry, src_clip);
+
+		dst_clip = dst_entry->start + (src_entry->end - src_entry->start);
+		vm_map_clip_end(dst_map, dst_entry, dst_clip);
+
+		/*
+		 *	Both entries now match in size and relative endpoints.
+		 *
+		 *	If both entries refer to a VM object, we can
+		 *	deal with them now.
+		 */
+
+		if (!src_entry->is_a_map && !dst_entry->is_a_map) {
+			vm_map_copy_entry(src_map, dst_map, src_entry,
+						dst_entry);
+		}
+		else {
+			register vm_map_t	new_dst_map;
+			vm_offset_t		new_dst_start;
+			vm_size_t		new_size;
+			vm_map_t		new_src_map;
+			vm_offset_t		new_src_start;
+
+			/*
+			 *	We have to follow at least one sharing map.
+			 */
+
+			new_size = (dst_entry->end - dst_entry->start);
+
+			if (src_entry->is_a_map) {
+				new_src_map = src_entry->object.share_map;
+				new_src_start = src_entry->offset;
+			}
+			else {
+			 	new_src_map = src_map;
+				new_src_start = src_entry->start;
+				lock_set_recursive(&src_map->lock);
+			}
+
+			if (dst_entry->is_a_map) {
+			    	vm_offset_t	new_dst_end;
+
+				new_dst_map = dst_entry->object.share_map;
+				new_dst_start = dst_entry->offset;
+
+				/*
+				 *	Since the destination sharing entries
+				 *	will be merely deallocated, we can
+				 *	do that now, and replace the region
+				 *	with a null object.  [This prevents
+				 *	splitting the source map to match
+				 *	the form of the destination map.]
+				 *	Note that we can only do so if the
+				 *	source and destination do not overlap.
+				 */
+
+				new_dst_end = new_dst_start + new_size;
+
+				if (new_dst_map != new_src_map) {
+					vm_map_lock(new_dst_map);
+					(void) vm_map_delete(new_dst_map,
+							new_dst_start,
+							new_dst_end);
+					(void) vm_map_insert(new_dst_map,
+							NULL,
+							(vm_offset_t) 0,
+							new_dst_start,
+							new_dst_end);
+					vm_map_unlock(new_dst_map);
+				}
+			}
+			else {
+			 	new_dst_map = dst_map;
+				new_dst_start = dst_entry->start;
+				lock_set_recursive(&dst_map->lock);
+			}
+
+			/*
+			 *	Recursively copy the sharing map.
+			 */
+
+			(void) vm_map_copy(new_dst_map, new_src_map,
+				new_dst_start, new_size, new_src_start,
+				FALSE, FALSE);
+
+			if (dst_map == new_dst_map)
+				lock_clear_recursive(&dst_map->lock);
+			if (src_map == new_src_map)
+				lock_clear_recursive(&src_map->lock);
+		}
+
+		/*
+		 *	Update variables for next pass through the loop.
+		 */
+
+		src_start = src_entry->end;
+		src_entry = src_entry->next;
+		dst_start = dst_entry->end;
+		dst_entry = dst_entry->next;
+
+		/*
+		 *	If the source is to be destroyed, here is the
+		 *	place to do it.
+		 */
+
+		if (src_destroy && src_map->is_main_map &&
+						dst_map->is_main_map)
+			vm_map_entry_delete(src_map, src_entry->prev);
+	}
+
+	/*
+	 *	Update the physical maps as appropriate
+	 */
+
+	if (src_map->is_main_map && dst_map->is_main_map) {
+		if (src_destroy)
+			pmap_remove(src_map->pmap, src_addr, src_addr + len);
+	}
+
+	/*
+	 *	Unlock the maps
+	 */
+
+	Return: ;
+
+	if (old_src_destroy)
+		vm_map_delete(src_map, src_addr, src_addr + len);
+
+	vm_map_unlock(src_map);
+	if (src_map != dst_map)
+		vm_map_unlock(dst_map);
+
+	return(result);
+}
+
+/*
+ * vmspace_fork:
+ * Create a new process vmspace structure and vm_map
+ * based on those of an existing process.  The new map
+ * is based on the old map, according to the inheritance
+ * values on the regions in that map.
+ *
+ * The source map must not be locked.
+ */
+struct vmspace *
+vmspace_fork(vm1)
+	register struct vmspace *vm1;
+{
+	register struct vmspace *vm2;
+	vm_map_t	old_map = &vm1->vm_map;
+	vm_map_t	new_map;
+	vm_map_entry_t	old_entry;
+	vm_map_entry_t	new_entry;
+	pmap_t		new_pmap;
+
+	vm_map_lock(old_map);
+
+	vm2 = vmspace_alloc(old_map->min_offset, old_map->max_offset,
+	    old_map->entries_pageable);
+	bcopy(&vm1->vm_startcopy, &vm2->vm_startcopy,
+	    (caddr_t) (vm1 + 1) - (caddr_t) &vm1->vm_startcopy);
+	new_pmap = &vm2->vm_pmap;		/* XXX */
+	new_map = &vm2->vm_map;			/* XXX */
+
+	old_entry = old_map->header.next;
+
+	while (old_entry != &old_map->header) {
+		if (old_entry->is_sub_map)
+			panic("vm_map_fork: encountered a submap");
+
+		switch (old_entry->inheritance) {
+		case VM_INHERIT_NONE:
+			break;
+
+		case VM_INHERIT_SHARE:
+			/*
+			 *	If we don't already have a sharing map:
+			 */
+
+			if (!old_entry->is_a_map) {
+			 	vm_map_t	new_share_map;
+				vm_map_entry_t	new_share_entry;
+				
+				/*
+				 *	Create a new sharing map
+				 */
+				 
+				new_share_map = vm_map_create(NULL,
+							old_entry->start,
+							old_entry->end,
+							TRUE);
+				new_share_map->is_main_map = FALSE;
+
+				/*
+				 *	Create the only sharing entry from the
+				 *	old task map entry.
+				 */
+
+				new_share_entry =
+					vm_map_entry_create(new_share_map);
+				*new_share_entry = *old_entry;
+				new_share_entry->wired_count = 0;
+
+				/*
+				 *	Insert the entry into the new sharing
+				 *	map
+				 */
+
+				vm_map_entry_link(new_share_map,
+						new_share_map->header.prev,
+						new_share_entry);
+
+				/*
+				 *	Fix up the task map entry to refer
+				 *	to the sharing map now.
+				 */
+
+				old_entry->is_a_map = TRUE;
+				old_entry->object.share_map = new_share_map;
+				old_entry->offset = old_entry->start;
+			}
+
+			/*
+			 *	Clone the entry, referencing the sharing map.
+			 */
+
+			new_entry = vm_map_entry_create(new_map);
+			*new_entry = *old_entry;
+			new_entry->wired_count = 0;
+			vm_map_reference(new_entry->object.share_map);
+
+			/*
+			 *	Insert the entry into the new map -- we
+			 *	know we're inserting at the end of the new
+			 *	map.
+			 */
+
+			vm_map_entry_link(new_map, new_map->header.prev,
+						new_entry);
+
+			/*
+			 *	Update the physical map
+			 */
+
+			pmap_copy(new_map->pmap, old_map->pmap,
+				new_entry->start,
+				(old_entry->end - old_entry->start),
+				old_entry->start);
+			break;
+
+		case VM_INHERIT_COPY:
+			/*
+			 *	Clone the entry and link into the map.
+			 */
+
+			new_entry = vm_map_entry_create(new_map);
+			*new_entry = *old_entry;
+			new_entry->wired_count = 0;
+			new_entry->object.vm_object = NULL;
+			new_entry->is_a_map = FALSE;
+			vm_map_entry_link(new_map, new_map->header.prev,
+							new_entry);
+			if (old_entry->is_a_map) {
+				int	check;
+
+				check = vm_map_copy(new_map,
+						old_entry->object.share_map,
+						new_entry->start,
+						(vm_size_t)(new_entry->end -
+							new_entry->start),
+						old_entry->offset,
+						FALSE, FALSE);
+				if (check != KERN_SUCCESS)
+					printf("vm_map_fork: copy in share_map region failed\n");
+			}
+			else {
+				vm_map_copy_entry(old_map, new_map, old_entry,
+						new_entry);
+			}
+			break;
+		}
+		old_entry = old_entry->next;
+	}
+
+	new_map->size = old_map->size;
+	vm_map_unlock(old_map);
+
+	return(vm2);
+}
+
+/*
+ *	vm_map_lookup:
+ *
+ *	Finds the VM object, offset, and
+ *	protection for a given virtual address in the
+ *	specified map, assuming a page fault of the
+ *	type specified.
+ *
+ *	Leaves the map in question locked for read; return
+ *	values are guaranteed until a vm_map_lookup_done
+ *	call is performed.  Note that the map argument
+ *	is in/out; the returned map must be used in
+ *	the call to vm_map_lookup_done.
+ *
+ *	A handle (out_entry) is returned for use in
+ *	vm_map_lookup_done, to make that fast.
+ *
+ *	If a lookup is requested with "write protection"
+ *	specified, the map may be changed to perform virtual
+ *	copying operations, although the data referenced will
+ *	remain the same.
+ */
+int
+vm_map_lookup(var_map, vaddr, fault_type, out_entry,
+				object, offset, out_prot, wired, single_use)
+	vm_map_t		*var_map;	/* IN/OUT */
+	register vm_offset_t	vaddr;
+	register vm_prot_t	fault_type;
+
+	vm_map_entry_t		*out_entry;	/* OUT */
+	vm_object_t		*object;	/* OUT */
+	vm_offset_t		*offset;	/* OUT */
+	vm_prot_t		*out_prot;	/* OUT */
+	boolean_t		*wired;		/* OUT */
+	boolean_t		*single_use;	/* OUT */
+{
+	vm_map_t			share_map;
+	vm_offset_t			share_offset;
+	register vm_map_entry_t		entry;
+	register vm_map_t		map = *var_map;
+	register vm_prot_t		prot;
+	register boolean_t		su;
+
+	RetryLookup: ;
+
+	/*
+	 *	Lookup the faulting address.
+	 */
+
+	vm_map_lock_read(map);
+
+#define	RETURN(why) \
+		{ \
+		vm_map_unlock_read(map); \
+		return(why); \
+		}
+
+	/*
+	 *	If the map has an interesting hint, try it before calling
+	 *	full blown lookup routine.
+	 */
+
+	simple_lock(&map->hint_lock);
+	entry = map->hint;
+	simple_unlock(&map->hint_lock);
+
+	*out_entry = entry;
+
+	if ((entry == &map->header) ||
+	    (vaddr < entry->start) || (vaddr >= entry->end)) {
+		vm_map_entry_t	tmp_entry;
+
+		/*
+		 *	Entry was either not a valid hint, or the vaddr
+		 *	was not contained in the entry, so do a full lookup.
+		 */
+		if (!vm_map_lookup_entry(map, vaddr, &tmp_entry))
+			RETURN(KERN_INVALID_ADDRESS);
+
+		entry = tmp_entry;
+		*out_entry = entry;
+	}
+
+	/*
+	 *	Handle submaps.
+	 */
+
+	if (entry->is_sub_map) {
+		vm_map_t	old_map = map;
+
+		*var_map = map = entry->object.sub_map;
+		vm_map_unlock_read(old_map);
+		goto RetryLookup;
+	}
+		
+	/*
+	 *	Check whether this task is allowed to have
+	 *	this page.
+	 */
+
+	prot = entry->protection;
+	if ((fault_type & (prot)) != fault_type)
+		RETURN(KERN_PROTECTION_FAILURE);
+
+	/*
+	 *	If this page is not pageable, we have to get
+	 *	it for all possible accesses.
+	 */
+
+	if (*wired = (entry->wired_count != 0))
+		prot = fault_type = entry->protection;
+
+	/*
+	 *	If we don't already have a VM object, track
+	 *	it down.
+	 */
+
+	if (su = !entry->is_a_map) {
+	 	share_map = map;
+		share_offset = vaddr;
+	}
+	else {
+		vm_map_entry_t	share_entry;
+
+		/*
+		 *	Compute the sharing map, and offset into it.
+		 */
+
+		share_map = entry->object.share_map;
+		share_offset = (vaddr - entry->start) + entry->offset;
+
+		/*
+		 *	Look for the backing store object and offset
+		 */
+
+		vm_map_lock_read(share_map);
+
+		if (!vm_map_lookup_entry(share_map, share_offset,
+					&share_entry)) {
+			vm_map_unlock_read(share_map);
+			RETURN(KERN_INVALID_ADDRESS);
+		}
+		entry = share_entry;
+	}
+
+	/*
+	 *	If the entry was copy-on-write, we either ...
+	 */
+
+	if (entry->needs_copy) {
+	    	/*
+		 *	If we want to write the page, we may as well
+		 *	handle that now since we've got the sharing
+		 *	map locked.
+		 *
+		 *	If we don't need to write the page, we just
+		 *	demote the permissions allowed.
+		 */
+
+		if (fault_type & VM_PROT_WRITE) {
+			/*
+			 *	Make a new object, and place it in the
+			 *	object chain.  Note that no new references
+			 *	have appeared -- one just moved from the
+			 *	share map to the new object.
+			 */
+
+			if (lock_read_to_write(&share_map->lock)) {
+				if (share_map != map)
+					vm_map_unlock_read(map);
+				goto RetryLookup;
+			}
+
+			vm_object_shadow(
+				&entry->object.vm_object,
+				&entry->offset,
+				(vm_size_t) (entry->end - entry->start));
+				
+			entry->needs_copy = FALSE;
+			
+			lock_write_to_read(&share_map->lock);
+		}
+		else {
+			/*
+			 *	We're attempting to read a copy-on-write
+			 *	page -- don't allow writes.
+			 */
+
+			prot &= (~VM_PROT_WRITE);
+		}
+	}
+
+	/*
+	 *	Create an object if necessary.
+	 */
+	if (entry->object.vm_object == NULL) {
+
+		if (lock_read_to_write(&share_map->lock)) {
+			if (share_map != map)
+				vm_map_unlock_read(map);
+			goto RetryLookup;
+		}
+
+		entry->object.vm_object = vm_object_allocate(
+					(vm_size_t)(entry->end - entry->start));
+		entry->offset = 0;
+		lock_write_to_read(&share_map->lock);
+	}
+
+	/*
+	 *	Return the object/offset from this entry.  If the entry
+	 *	was copy-on-write or empty, it has been fixed up.
+	 */
+
+	*offset = (share_offset - entry->start) + entry->offset;
+	*object = entry->object.vm_object;
+
+	/*
+	 *	Return whether this is the only map sharing this data.
+	 */
+
+	if (!su) {
+		simple_lock(&share_map->ref_lock);
+		su = (share_map->ref_count == 1);
+		simple_unlock(&share_map->ref_lock);
+	}
+
+	*out_prot = prot;
+	*single_use = su;
+
+	return(KERN_SUCCESS);
+	
+#undef	RETURN
+}
+
+/*
+ *	vm_map_lookup_done:
+ *
+ *	Releases locks acquired by a vm_map_lookup
+ *	(according to the handle returned by that lookup).
+ */
+
+void vm_map_lookup_done(map, entry)
+	register vm_map_t	map;
+	vm_map_entry_t		entry;
+{
+	/*
+	 *	If this entry references a map, unlock it first.
+	 */
+
+	if (entry->is_a_map)
+		vm_map_unlock_read(entry->object.share_map);
+
+	/*
+	 *	Unlock the main-level map
+	 */
+
+	vm_map_unlock_read(map);
+}
+
+/*
+ *	Routine:	vm_map_simplify
+ *	Purpose:
+ *		Attempt to simplify the map representation in
+ *		the vicinity of the given starting address.
+ *	Note:
+ *		This routine is intended primarily to keep the
+ *		kernel maps more compact -- they generally don't
+ *		benefit from the "expand a map entry" technology
+ *		at allocation time because the adjacent entry
+ *		is often wired down.
+ */
+void vm_map_simplify(map, start)
+	vm_map_t	map;
+	vm_offset_t	start;
+{
+	vm_map_entry_t	this_entry;
+	vm_map_entry_t	prev_entry;
+
+	vm_map_lock(map);
+	if (
+		(vm_map_lookup_entry(map, start, &this_entry)) &&
+		((prev_entry = this_entry->prev) != &map->header) &&
+
+		(prev_entry->end == start) &&
+		(map->is_main_map) &&
+
+		(prev_entry->is_a_map == FALSE) &&
+		(prev_entry->is_sub_map == FALSE) &&
+
+		(this_entry->is_a_map == FALSE) &&
+		(this_entry->is_sub_map == FALSE) &&
+
+		(prev_entry->inheritance == this_entry->inheritance) &&
+		(prev_entry->protection == this_entry->protection) &&
+		(prev_entry->max_protection == this_entry->max_protection) &&
+		(prev_entry->wired_count == this_entry->wired_count) &&
+		
+		(prev_entry->copy_on_write == this_entry->copy_on_write) &&
+		(prev_entry->needs_copy == this_entry->needs_copy) &&
+		
+		(prev_entry->object.vm_object == this_entry->object.vm_object) &&
+		((prev_entry->offset + (prev_entry->end - prev_entry->start))
+		     == this_entry->offset)
+	) {
+		if (map->first_free == this_entry)
+			map->first_free = prev_entry;
+
+		SAVE_HINT(map, prev_entry);
+		vm_map_entry_unlink(map, this_entry);
+		prev_entry->end = this_entry->end;
+	 	vm_object_deallocate(this_entry->object.vm_object);
+		vm_map_entry_dispose(map, this_entry);
+	}
+	vm_map_unlock(map);
+}
+
+/*
+ *	vm_map_print:	[ debug ]
+ */
+void vm_map_print(map, full)
+	register vm_map_t	map;
+	boolean_t		full;
+{
+	register vm_map_entry_t	entry;
+	extern int indent;
+
+	iprintf("%s map 0x%x: pmap=0x%x,ref=%d,nentries=%d,version=%d\n",
+		(map->is_main_map ? "Task" : "Share"),
+ 		(int) map, (int) (map->pmap), map->ref_count, map->nentries,
+		map->timestamp);
+
+	if (!full && indent)
+		return;
+
+	indent += 2;
+	for (entry = map->header.next; entry != &map->header;
+				entry = entry->next) {
+		iprintf("map entry 0x%x: start=0x%x, end=0x%x, ",
+			(int) entry, (int) entry->start, (int) entry->end);
+		if (map->is_main_map) {
+		     	static char *inheritance_name[4] =
+				{ "share", "copy", "none", "donate_copy"};
+			printf("prot=%x/%x/%s, ",
+				entry->protection,
+				entry->max_protection,
+				inheritance_name[entry->inheritance]);
+			if (entry->wired_count != 0)
+				printf("wired, ");
+		}
+
+		if (entry->is_a_map || entry->is_sub_map) {
+		 	printf("share=0x%x, offset=0x%x\n",
+				(int) entry->object.share_map,
+				(int) entry->offset);
+			if ((entry->prev == &map->header) ||
+			    (!entry->prev->is_a_map) ||
+			    (entry->prev->object.share_map !=
+			     entry->object.share_map)) {
+				indent += 2;
+				vm_map_print(entry->object.share_map, full);
+				indent -= 2;
+			}
+				
+		}
+		else {
+			printf("object=0x%x, offset=0x%x",
+				(int) entry->object.vm_object,
+				(int) entry->offset);
+			if (entry->copy_on_write)
+				printf(", copy (%s)",
+				       entry->needs_copy ? "needed" : "done");
+			printf("\n");
+
+			if ((entry->prev == &map->header) ||
+			    (entry->prev->is_a_map) ||
+			    (entry->prev->object.vm_object !=
+			     entry->object.vm_object)) {
+				indent += 2;
+				vm_object_print(entry->object.vm_object, full);
+				indent -= 2;
+			}
+		}
+	}
+	indent -= 2;
+}
diff --git a/sys/vm/vm_map.h b/sys/vm/vm_map.h
new file mode 100644
index 0000000..d25b7a2
--- /dev/null
+++ b/sys/vm/vm_map.h
@@ -0,0 +1,228 @@
+/* 
+ * Copyright (c) 1991, 1993
+ *	The Regents of the University of California.  All rights reserved.
+ *
+ * This code is derived from software contributed to Berkeley by
+ * The Mach Operating System project at Carnegie-Mellon University.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. All advertising materials mentioning features or use of this software
+ *    must display the following acknowledgement:
+ *	This product includes software developed by the University of
+ *	California, Berkeley and its contributors.
+ * 4. Neither the name of the University nor the names of its contributors
+ *    may be used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ *
+ *	@(#)vm_map.h	8.3 (Berkeley) 3/15/94
+ *
+ *
+ * Copyright (c) 1987, 1990 Carnegie-Mellon University.
+ * All rights reserved.
+ *
+ * Authors: Avadis Tevanian, Jr., Michael Wayne Young
+ * 
+ * Permission to use, copy, modify and distribute this software and
+ * its documentation is hereby granted, provided that both the copyright
+ * notice and this permission notice appear in all copies of the
+ * software, derivative works or modified versions, and any portions
+ * thereof, and that both notices appear in supporting documentation.
+ * 
+ * CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS" 
+ * CONDITION.  CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND 
+ * FOR ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
+ * 
+ * Carnegie Mellon requests users of this software to return to
+ *
+ *  Software Distribution Coordinator  or  Software.Distribution@CS.CMU.EDU
+ *  School of Computer Science
+ *  Carnegie Mellon University
+ *  Pittsburgh PA 15213-3890
+ *
+ * any improvements or extensions that they make and grant Carnegie the
+ * rights to redistribute these changes.
+ */
+
+/*
+ *	Virtual memory map module definitions.
+ */
+
+#ifndef	_VM_MAP_
+#define	_VM_MAP_
+
+/*
+ *	Types defined:
+ *
+ *	vm_map_t		the high-level address map data structure.
+ *	vm_map_entry_t		an entry in an address map.
+ *	vm_map_version_t	a timestamp of a map, for use with vm_map_lookup
+ */
+
+/*
+ *	Objects which live in maps may be either VM objects, or
+ *	another map (called a "sharing map") which denotes read-write
+ *	sharing with other maps.
+ */
+
+union vm_map_object {
+	struct vm_object	*vm_object;	/* object object */
+	struct vm_map		*share_map;	/* share map */
+	struct vm_map		*sub_map;	/* belongs to another map */
+};
+
+/*
+ *	Address map entries consist of start and end addresses,
+ *	a VM object (or sharing map) and offset into that object,
+ *	and user-exported inheritance and protection information.
+ *	Also included is control information for virtual copy operations.
+ */
+struct vm_map_entry {
+	struct vm_map_entry	*prev;		/* previous entry */
+	struct vm_map_entry	*next;		/* next entry */
+	vm_offset_t		start;		/* start address */
+	vm_offset_t		end;		/* end address */
+	union vm_map_object	object;		/* object I point to */
+	vm_offset_t		offset;		/* offset into object */
+	boolean_t		is_a_map;	/* Is "object" a map? */
+	boolean_t		is_sub_map;	/* Is "object" a submap? */
+		/* Only in sharing maps: */
+	boolean_t		copy_on_write;	/* is data copy-on-write */
+	boolean_t		needs_copy;	/* does object need to be copied */
+		/* Only in task maps: */
+	vm_prot_t		protection;	/* protection code */
+	vm_prot_t		max_protection;	/* maximum protection */
+	vm_inherit_t		inheritance;	/* inheritance */
+	int			wired_count;	/* can be paged if = 0 */
+};
+
+/*
+ *	Maps are doubly-linked lists of map entries, kept sorted
+ *	by address.  A single hint is provided to start
+ *	searches again from the last successful search,
+ *	insertion, or removal.
+ */
+struct vm_map {
+	struct pmap *		pmap;		/* Physical map */
+	lock_data_t		lock;		/* Lock for map data */
+	struct vm_map_entry	header;		/* List of entries */
+	int			nentries;	/* Number of entries */
+	vm_size_t		size;		/* virtual size */
+	boolean_t		is_main_map;	/* Am I a main map? */
+	int			ref_count;	/* Reference count */
+	simple_lock_data_t	ref_lock;	/* Lock for ref_count field */
+	vm_map_entry_t		hint;		/* hint for quick lookups */
+	simple_lock_data_t	hint_lock;	/* lock for hint storage */
+	vm_map_entry_t		first_free;	/* First free space hint */
+	boolean_t		entries_pageable; /* map entries pageable?? */
+	unsigned int		timestamp;	/* Version number */
+#define	min_offset		header.start
+#define max_offset		header.end
+};
+
+/*
+ *	Map versions are used to validate a previous lookup attempt.
+ *
+ *	Since lookup operations may involve both a main map and
+ *	a sharing map, it is necessary to have a timestamp from each.
+ *	[If the main map timestamp has changed, the share_map and
+ *	associated timestamp are no longer valid; the map version
+ *	does not include a reference for the imbedded share_map.]
+ */
+typedef struct {
+	int		main_timestamp;
+	vm_map_t	share_map;
+	int		share_timestamp;
+} vm_map_version_t;
+
+/*
+ *	Macros:		vm_map_lock, etc.
+ *	Function:
+ *		Perform locking on the data portion of a map.
+ */
+
+#define	vm_map_lock(map) { \
+	lock_write(&(map)->lock); \
+	(map)->timestamp++; \
+}
+#define	vm_map_unlock(map)	lock_write_done(&(map)->lock)
+#define	vm_map_lock_read(map)	lock_read(&(map)->lock)
+#define	vm_map_unlock_read(map)	lock_read_done(&(map)->lock)
+
+/*
+ *	Functions implemented as macros
+ */
+#define		vm_map_min(map)		((map)->min_offset)
+#define		vm_map_max(map)		((map)->max_offset)
+#define		vm_map_pmap(map)	((map)->pmap)
+
+/* XXX: number of kernel maps and entries to statically allocate */
+#define MAX_KMAP	10
+#define	MAX_KMAPENT	500
+
+#ifdef KERNEL
+boolean_t	 vm_map_check_protection __P((vm_map_t,
+		    vm_offset_t, vm_offset_t, vm_prot_t));
+int		 vm_map_copy __P((vm_map_t, vm_map_t, vm_offset_t,
+		    vm_size_t, vm_offset_t, boolean_t, boolean_t));
+void		 vm_map_copy_entry __P((vm_map_t,
+		    vm_map_t, vm_map_entry_t, vm_map_entry_t));
+struct pmap;
+vm_map_t	 vm_map_create __P((struct pmap *,
+		    vm_offset_t, vm_offset_t, boolean_t));
+void		 vm_map_deallocate __P((vm_map_t));
+int		 vm_map_delete __P((vm_map_t, vm_offset_t, vm_offset_t));
+vm_map_entry_t	 vm_map_entry_create __P((vm_map_t));
+void		 vm_map_entry_delete __P((vm_map_t, vm_map_entry_t));
+void		 vm_map_entry_dispose __P((vm_map_t, vm_map_entry_t));
+void		 vm_map_entry_unwire __P((vm_map_t, vm_map_entry_t));
+int		 vm_map_find __P((vm_map_t, vm_object_t,
+		    vm_offset_t, vm_offset_t *, vm_size_t, boolean_t));
+int		 vm_map_findspace __P((vm_map_t,
+		    vm_offset_t, vm_size_t, vm_offset_t *));
+int		 vm_map_inherit __P((vm_map_t,
+		    vm_offset_t, vm_offset_t, vm_inherit_t));
+void		 vm_map_init __P((struct vm_map *,
+		    vm_offset_t, vm_offset_t, boolean_t));
+int		 vm_map_insert __P((vm_map_t,
+		    vm_object_t, vm_offset_t, vm_offset_t, vm_offset_t));
+int		 vm_map_lookup __P((vm_map_t *, vm_offset_t, vm_prot_t,
+		    vm_map_entry_t *, vm_object_t *, vm_offset_t *, vm_prot_t *,
+		    boolean_t *, boolean_t *));
+void		 vm_map_lookup_done __P((vm_map_t, vm_map_entry_t));
+boolean_t	 vm_map_lookup_entry __P((vm_map_t,
+		    vm_offset_t, vm_map_entry_t *));
+int		 vm_map_pageable __P((vm_map_t,
+		    vm_offset_t, vm_offset_t, boolean_t));
+int		 vm_map_clean __P((vm_map_t,
+		    vm_offset_t, vm_offset_t, boolean_t, boolean_t));
+void		 vm_map_print __P((vm_map_t, boolean_t));
+int		 vm_map_protect __P((vm_map_t,
+		    vm_offset_t, vm_offset_t, vm_prot_t, boolean_t));
+void		 vm_map_reference __P((vm_map_t));
+int		 vm_map_remove __P((vm_map_t, vm_offset_t, vm_offset_t));
+void		 vm_map_simplify __P((vm_map_t, vm_offset_t));
+void		 vm_map_simplify_entry __P((vm_map_t, vm_map_entry_t));
+void		 vm_map_startup __P((void));
+int		 vm_map_submap __P((vm_map_t,
+		    vm_offset_t, vm_offset_t, vm_map_t));
+#endif
+#endif /* _VM_MAP_ */
diff --git a/sys/vm/vm_meter.c b/sys/vm/vm_meter.c
new file mode 100644
index 0000000..9db6f50
--- /dev/null
+++ b/sys/vm/vm_meter.c
@@ -0,0 +1,224 @@
+/*
+ * Copyright (c) 1982, 1986, 1989, 1993
+ *	The Regents of the University of California.  All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. All advertising materials mentioning features or use of this software
+ *    must display the following acknowledgement:
+ *	This product includes software developed by the University of
+ *	California, Berkeley and its contributors.
+ * 4. Neither the name of the University nor the names of its contributors
+ *    may be used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ *
+ *	@(#)vm_meter.c	8.4 (Berkeley) 1/4/94
+ */
+
+#include <sys/param.h>
+#include <sys/proc.h>
+#include <sys/systm.h>
+#include <sys/kernel.h>
+#include <vm/vm.h>
+#include <sys/sysctl.h>
+
+struct	loadavg averunnable;		/* load average, of runnable procs */
+
+int	maxslp = MAXSLP;
+int	saferss = SAFERSS;
+
+void
+vmmeter()
+{
+
+	if (time.tv_sec % 5 == 0)
+		loadav(&averunnable);
+	if (proc0.p_slptime > maxslp/2)
+		wakeup((caddr_t)&proc0);
+}
+
+/*
+ * Constants for averages over 1, 5, and 15 minutes
+ * when sampling at 5 second intervals.
+ */
+fixpt_t	cexp[3] = {
+	0.9200444146293232 * FSCALE,	/* exp(-1/12) */
+	0.9834714538216174 * FSCALE,	/* exp(-1/60) */
+	0.9944598480048967 * FSCALE,	/* exp(-1/180) */
+};
+
+/*
+ * Compute a tenex style load average of a quantity on
+ * 1, 5 and 15 minute intervals.
+ */
+void
+loadav(avg)
+	register struct loadavg *avg;
+{
+	register int i, nrun;
+	register struct proc *p;
+
+	for (nrun = 0, p = (struct proc *)allproc; p != NULL; p = p->p_next) {
+		switch (p->p_stat) {
+		case SSLEEP:
+			if (p->p_priority > PZERO || p->p_slptime != 0)
+				continue;
+			/* fall through */
+		case SRUN:
+		case SIDL:
+			nrun++;
+		}
+	}
+	for (i = 0; i < 3; i++)
+		avg->ldavg[i] = (cexp[i] * avg->ldavg[i] +
+			nrun * FSCALE * (FSCALE - cexp[i])) >> FSHIFT;
+}
+
+/*
+ * Attributes associated with virtual memory.
+ */
+vm_sysctl(name, namelen, oldp, oldlenp, newp, newlen, p)
+	int *name;
+	u_int namelen;
+	void *oldp;
+	size_t *oldlenp;
+	void *newp;
+	size_t newlen;
+	struct proc *p;
+{
+	struct vmtotal vmtotals;
+
+	/* all sysctl names at this level are terminal */
+	if (namelen != 1)
+		return (ENOTDIR);		/* overloaded */
+
+	switch (name[0]) {
+	case VM_LOADAVG:
+		averunnable.fscale = FSCALE;
+		return (sysctl_rdstruct(oldp, oldlenp, newp, &averunnable,
+		    sizeof(averunnable)));
+	case VM_METER:
+		vmtotal(&vmtotals);
+		return (sysctl_rdstruct(oldp, oldlenp, newp, &vmtotals,
+		    sizeof(vmtotals)));
+	default:
+		return (EOPNOTSUPP);
+	}
+	/* NOTREACHED */
+}
+
+/*
+ * Calculate the current state of the system.
+ * Done on demand from getkerninfo().
+ */
+void
+vmtotal(totalp)
+	register struct vmtotal *totalp;
+{
+	register struct proc *p;
+	register vm_map_entry_t	entry;
+	register vm_object_t object;
+	register vm_map_t map;
+	int paging;
+
+	bzero(totalp, sizeof *totalp);
+	/*
+	 * Mark all objects as inactive.
+	 */
+	simple_lock(&vm_object_list_lock);
+	for (object = vm_object_list.tqh_first;
+	     object != NULL;
+	     object = object->object_list.tqe_next)
+		object->flags &= ~OBJ_ACTIVE;
+	simple_unlock(&vm_object_list_lock);
+	/*
+	 * Calculate process statistics.
+	 */
+	for (p = (struct proc *)allproc; p != NULL; p = p->p_next) {
+		if (p->p_flag & P_SYSTEM)
+			continue;
+		switch (p->p_stat) {
+		case 0:
+			continue;
+
+		case SSLEEP:
+		case SSTOP:
+			if (p->p_flag & P_INMEM) {
+				if (p->p_priority <= PZERO)
+					totalp->t_dw++;
+				else if (p->p_slptime < maxslp)
+					totalp->t_sl++;
+			} else if (p->p_slptime < maxslp)
+				totalp->t_sw++;
+			if (p->p_slptime >= maxslp)
+				continue;
+			break;
+
+		case SRUN:
+		case SIDL:
+			if (p->p_flag & P_INMEM)
+				totalp->t_rq++;
+			else
+				totalp->t_sw++;
+			if (p->p_stat == SIDL)
+				continue;
+			break;
+		}
+		/*
+		 * Note active objects.
+		 */
+		paging = 0;
+		for (map = &p->p_vmspace->vm_map, entry = map->header.next;
+		     entry != &map->header; entry = entry->next) {
+			if (entry->is_a_map || entry->is_sub_map ||
+			    entry->object.vm_object == NULL)
+				continue;
+			entry->object.vm_object->flags |= OBJ_ACTIVE;
+			paging |= entry->object.vm_object->paging_in_progress;
+		}
+		if (paging)
+			totalp->t_pw++;
+	}
+	/*
+	 * Calculate object memory usage statistics.
+	 */
+	simple_lock(&vm_object_list_lock);
+	for (object = vm_object_list.tqh_first;
+	     object != NULL;
+	     object = object->object_list.tqe_next) {
+		totalp->t_vm += num_pages(object->size);
+		totalp->t_rm += object->resident_page_count;
+		if (object->flags & OBJ_ACTIVE) {
+			totalp->t_avm += num_pages(object->size);
+			totalp->t_arm += object->resident_page_count;
+		}
+		if (object->ref_count > 1) {
+			/* shared object */
+			totalp->t_vmshr += num_pages(object->size);
+			totalp->t_rmshr += object->resident_page_count;
+			if (object->flags & OBJ_ACTIVE) {
+				totalp->t_avmshr += num_pages(object->size);
+				totalp->t_armshr += object->resident_page_count;
+			}
+		}
+	}
+	totalp->t_free = cnt.v_free_count;
+}
diff --git a/sys/vm/vm_mmap.c b/sys/vm/vm_mmap.c
new file mode 100644
index 0000000..340cded
--- /dev/null
+++ b/sys/vm/vm_mmap.c
@@ -0,0 +1,832 @@
+/*
+ * Copyright (c) 1988 University of Utah.
+ * Copyright (c) 1991, 1993
+ *	The Regents of the University of California.  All rights reserved.
+ *
+ * This code is derived from software contributed to Berkeley by
+ * the Systems Programming Group of the University of Utah Computer
+ * Science Department.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. All advertising materials mentioning features or use of this software
+ *    must display the following acknowledgement:
+ *	This product includes software developed by the University of
+ *	California, Berkeley and its contributors.
+ * 4. Neither the name of the University nor the names of its contributors
+ *    may be used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ *
+ * from: Utah $Hdr: vm_mmap.c 1.6 91/10/21$
+ *
+ *	@(#)vm_mmap.c	8.4 (Berkeley) 1/12/94
+ */
+
+/*
+ * Mapped file (mmap) interface to VM
+ */
+
+#include <sys/param.h>
+#include <sys/systm.h>
+#include <sys/filedesc.h>
+#include <sys/resourcevar.h>
+#include <sys/proc.h>
+#include <sys/vnode.h>
+#include <sys/file.h>
+#include <sys/mman.h>
+#include <sys/conf.h>
+
+#include <miscfs/specfs/specdev.h>
+
+#include <vm/vm.h>
+#include <vm/vm_pager.h>
+#include <vm/vm_prot.h>
+
+#ifdef DEBUG
+int mmapdebug = 0;
+#define MDB_FOLLOW	0x01
+#define MDB_SYNC	0x02
+#define MDB_MAPIT	0x04
+#endif
+
+struct sbrk_args {
+	int	incr;
+};
+/* ARGSUSED */
+int
+sbrk(p, uap, retval)
+	struct proc *p;
+	struct sbrk_args *uap;
+	int *retval;
+{
+
+	/* Not yet implemented */
+	return (EOPNOTSUPP);
+}
+
+struct sstk_args {
+	int	incr;
+};
+/* ARGSUSED */
+int
+sstk(p, uap, retval)
+	struct proc *p;
+	struct sstk_args *uap;
+	int *retval;
+{
+
+	/* Not yet implemented */
+	return (EOPNOTSUPP);
+}
+
+#if defined(COMPAT_43) || defined(COMPAT_SUNOS)
+struct getpagesize_args {
+	int	dummy;
+};
+/* ARGSUSED */
+int
+ogetpagesize(p, uap, retval)
+	struct proc *p;
+	struct getpagesize_args *uap;
+	int *retval;
+{
+
+	*retval = PAGE_SIZE;
+	return (0);
+}
+#endif /* COMPAT_43 || COMPAT_SUNOS */
+
+struct mmap_args {
+	caddr_t	addr;
+	size_t	len;
+	int	prot;
+	int	flags;
+	int	fd;
+	long	pad;
+	off_t	pos;
+};
+
+#ifdef COMPAT_43
+struct ommap_args {
+	caddr_t	addr;
+	int	len;
+	int	prot;
+	int	flags;
+	int	fd;
+	long	pos;
+};
+int
+ommap(p, uap, retval)
+	struct proc *p;
+	register struct ommap_args *uap;
+	int *retval;
+{
+	struct mmap_args nargs;
+	static const char cvtbsdprot[8] = {
+		0,
+		PROT_EXEC,
+		PROT_WRITE,
+		PROT_EXEC|PROT_WRITE,
+		PROT_READ,
+		PROT_EXEC|PROT_READ,
+		PROT_WRITE|PROT_READ,
+		PROT_EXEC|PROT_WRITE|PROT_READ,
+	};
+#define	OMAP_ANON	0x0002
+#define	OMAP_COPY	0x0020
+#define	OMAP_SHARED	0x0010
+#define	OMAP_FIXED	0x0100
+#define	OMAP_INHERIT	0x0800
+
+	nargs.addr = uap->addr;
+	nargs.len = uap->len;
+	nargs.prot = cvtbsdprot[uap->prot&0x7];
+	nargs.flags = 0;
+	if (uap->flags & OMAP_ANON)
+		nargs.flags |= MAP_ANON;
+	if (uap->flags & OMAP_COPY)
+		nargs.flags |= MAP_COPY;
+	if (uap->flags & OMAP_SHARED)
+		nargs.flags |= MAP_SHARED;
+	else
+		nargs.flags |= MAP_PRIVATE;
+	if (uap->flags & OMAP_FIXED)
+		nargs.flags |= MAP_FIXED;
+	if (uap->flags & OMAP_INHERIT)
+		nargs.flags |= MAP_INHERIT;
+	nargs.fd = uap->fd;
+	nargs.pos = uap->pos;
+	return (mmap(p, &nargs, retval));
+}
+#endif
+
+int
+mmap(p, uap, retval)
+	struct proc *p;
+	register struct mmap_args *uap;
+	int *retval;
+{
+	register struct filedesc *fdp = p->p_fd;
+	register struct file *fp;
+	struct vnode *vp;
+	vm_offset_t addr;
+	vm_size_t size;
+	vm_prot_t prot, maxprot;
+	caddr_t handle;
+	int flags, error;
+
+	prot = uap->prot & VM_PROT_ALL;
+	flags = uap->flags;
+#ifdef DEBUG
+	if (mmapdebug & MDB_FOLLOW)
+		printf("mmap(%d): addr %x len %x pro %x flg %x fd %d pos %x\n",
+		       p->p_pid, uap->addr, uap->len, prot,
+		       flags, uap->fd, (vm_offset_t)uap->pos);
+#endif
+	/*
+	 * Address (if FIXED) must be page aligned.
+	 * Size is implicitly rounded to a page boundary.
+	 */
+	addr = (vm_offset_t) uap->addr;
+	if (((flags & MAP_FIXED) && (addr & PAGE_MASK)) ||
+	    (ssize_t)uap->len < 0 || ((flags & MAP_ANON) && uap->fd != -1))
+		return (EINVAL);
+	size = (vm_size_t) round_page(uap->len);
+	/*
+	 * Check for illegal addresses.  Watch out for address wrap...
+	 * Note that VM_*_ADDRESS are not constants due to casts (argh).
+	 */
+	if (flags & MAP_FIXED) {
+		if (VM_MAXUSER_ADDRESS > 0 && addr + size >= VM_MAXUSER_ADDRESS)
+			return (EINVAL);
+		if (VM_MIN_ADDRESS > 0 && addr < VM_MIN_ADDRESS)
+			return (EINVAL);
+		if (addr > addr + size)
+			return (EINVAL);
+	}
+	/*
+	 * XXX if no hint provided for a non-fixed mapping place it after
+	 * the end of the largest possible heap.
+	 *
+	 * There should really be a pmap call to determine a reasonable
+	 * location.
+	 */
+	if (addr == 0 && (flags & MAP_FIXED) == 0)
+		addr = round_page(p->p_vmspace->vm_daddr + MAXDSIZ);
+	if (flags & MAP_ANON) {
+		/*
+		 * Mapping blank space is trivial.
+		 */
+		handle = NULL;
+		maxprot = VM_PROT_ALL;
+	} else {
+		/*
+		 * Mapping file, get fp for validation.
+		 * Obtain vnode and make sure it is of appropriate type.
+		 */
+		if (((unsigned)uap->fd) >= fdp->fd_nfiles ||
+		    (fp = fdp->fd_ofiles[uap->fd]) == NULL)
+			return (EBADF);
+		if (fp->f_type != DTYPE_VNODE)
+			return (EINVAL);
+		vp = (struct vnode *)fp->f_data;
+		if (vp->v_type != VREG && vp->v_type != VCHR)
+			return (EINVAL);
+		/*
+		 * XXX hack to handle use of /dev/zero to map anon
+		 * memory (ala SunOS).
+		 */
+		if (vp->v_type == VCHR && iszerodev(vp->v_rdev)) {
+			handle = NULL;
+			maxprot = VM_PROT_ALL;
+			flags |= MAP_ANON;
+		} else {
+			/*
+			 * Ensure that file and memory protections are
+			 * compatible.  Note that we only worry about
+			 * writability if mapping is shared; in this case,
+			 * current and max prot are dictated by the open file.
+			 * XXX use the vnode instead?  Problem is: what
+			 * credentials do we use for determination?
+			 * What if proc does a setuid?
+			 */
+			maxprot = VM_PROT_EXECUTE;	/* ??? */
+			if (fp->f_flag & FREAD)
+				maxprot |= VM_PROT_READ;
+			else if (prot & PROT_READ)
+				return (EACCES);
+			if (flags & MAP_SHARED) {
+				if (fp->f_flag & FWRITE)
+					maxprot |= VM_PROT_WRITE;
+				else if (prot & PROT_WRITE)
+					return (EACCES);
+			} else
+				maxprot |= VM_PROT_WRITE;
+			handle = (caddr_t)vp;
+		}
+	}
+	error = vm_mmap(&p->p_vmspace->vm_map, &addr, size, prot, maxprot,
+	    flags, handle, (vm_offset_t)uap->pos);
+	if (error == 0)
+		*retval = (int)addr;
+	return (error);
+}
+
+struct msync_args {
+	caddr_t	addr;
+	int	len;
+};
+int
+msync(p, uap, retval)
+	struct proc *p;
+	struct msync_args *uap;
+	int *retval;
+{
+	vm_offset_t addr;
+	vm_size_t size;
+	vm_map_t map;
+	int rv;
+	boolean_t syncio, invalidate;
+
+#ifdef DEBUG
+	if (mmapdebug & (MDB_FOLLOW|MDB_SYNC))
+		printf("msync(%d): addr %x len %x\n",
+		       p->p_pid, uap->addr, uap->len);
+#endif
+	if (((int)uap->addr & PAGE_MASK) || uap->addr + uap->len < uap->addr)
+		return (EINVAL);
+	map = &p->p_vmspace->vm_map;
+	addr = (vm_offset_t)uap->addr;
+	size = (vm_size_t)uap->len;
+	/*
+	 * XXX Gak!  If size is zero we are supposed to sync "all modified
+	 * pages with the region containing addr".  Unfortunately, we
+	 * don't really keep track of individual mmaps so we approximate
+	 * by flushing the range of the map entry containing addr.
+	 * This can be incorrect if the region splits or is coalesced
+	 * with a neighbor.
+	 */
+	if (size == 0) {
+		vm_map_entry_t entry;
+
+		vm_map_lock_read(map);
+		rv = vm_map_lookup_entry(map, addr, &entry);
+		vm_map_unlock_read(map);
+		if (rv)
+			return (EINVAL);
+		addr = entry->start;
+		size = entry->end - entry->start;
+	}
+#ifdef DEBUG
+	if (mmapdebug & MDB_SYNC)
+		printf("msync: cleaning/flushing address range [%x-%x)\n",
+		       addr, addr+size);
+#endif
+	/*
+	 * Could pass this in as a third flag argument to implement
+	 * Sun's MS_ASYNC.
+	 */
+	syncio = TRUE;
+	/*
+	 * XXX bummer, gotta flush all cached pages to ensure
+	 * consistency with the file system cache.  Otherwise, we could
+	 * pass this in to implement Sun's MS_INVALIDATE.
+	 */
+	invalidate = TRUE;
+	/*
+	 * Clean the pages and interpret the return value.
+	 */
+	rv = vm_map_clean(map, addr, addr+size, syncio, invalidate);
+	switch (rv) {
+	case KERN_SUCCESS:
+		break;
+	case KERN_INVALID_ADDRESS:
+		return (EINVAL);	/* Sun returns ENOMEM? */
+	case KERN_FAILURE:
+		return (EIO);
+	default:
+		return (EINVAL);
+	}
+	return (0);
+}
+
+struct munmap_args {
+	caddr_t	addr;
+	int	len;
+};
+int
+munmap(p, uap, retval)
+	register struct proc *p;
+	register struct munmap_args *uap;
+	int *retval;
+{
+	vm_offset_t addr;
+	vm_size_t size;
+	vm_map_t map;
+
+#ifdef DEBUG
+	if (mmapdebug & MDB_FOLLOW)
+		printf("munmap(%d): addr %x len %x\n",
+		       p->p_pid, uap->addr, uap->len);
+#endif
+
+	addr = (vm_offset_t) uap->addr;
+	if ((addr & PAGE_MASK) || uap->len < 0)
+		return(EINVAL);
+	size = (vm_size_t) round_page(uap->len);
+	if (size == 0)
+		return(0);
+	/*
+	 * Check for illegal addresses.  Watch out for address wrap...
+	 * Note that VM_*_ADDRESS are not constants due to casts (argh).
+	 */
+	if (VM_MAXUSER_ADDRESS > 0 && addr + size >= VM_MAXUSER_ADDRESS)
+		return (EINVAL);
+	if (VM_MIN_ADDRESS > 0 && addr < VM_MIN_ADDRESS)
+		return (EINVAL);
+	if (addr > addr + size)
+		return (EINVAL);
+	map = &p->p_vmspace->vm_map;
+	/*
+	 * Make sure entire range is allocated.
+	 */
+	if (!vm_map_check_protection(map, addr, addr + size, VM_PROT_NONE))
+		return(EINVAL);
+	/* returns nothing but KERN_SUCCESS anyway */
+	(void) vm_map_remove(map, addr, addr+size);
+	return(0);
+}
+
+void
+munmapfd(fd)
+	int fd;
+{
+#ifdef DEBUG
+	if (mmapdebug & MDB_FOLLOW)
+		printf("munmapfd(%d): fd %d\n", curproc->p_pid, fd);
+#endif
+
+	/*
+	 * XXX should vm_deallocate any regions mapped to this file
+	 */
+	curproc->p_fd->fd_ofileflags[fd] &= ~UF_MAPPED;
+}
+
+struct mprotect_args {
+	caddr_t	addr;
+	int	len;
+	int	prot;
+};
+int
+mprotect(p, uap, retval)
+	struct proc *p;
+	struct mprotect_args *uap;
+	int *retval;
+{
+	vm_offset_t addr;
+	vm_size_t size;
+	register vm_prot_t prot;
+
+#ifdef DEBUG
+	if (mmapdebug & MDB_FOLLOW)
+		printf("mprotect(%d): addr %x len %x prot %d\n",
+		       p->p_pid, uap->addr, uap->len, uap->prot);
+#endif
+
+	addr = (vm_offset_t)uap->addr;
+	if ((addr & PAGE_MASK) || uap->len < 0)
+		return(EINVAL);
+	size = (vm_size_t)uap->len;
+	prot = uap->prot & VM_PROT_ALL;
+
+	switch (vm_map_protect(&p->p_vmspace->vm_map, addr, addr+size, prot,
+	    FALSE)) {
+	case KERN_SUCCESS:
+		return (0);
+	case KERN_PROTECTION_FAILURE:
+		return (EACCES);
+	}
+	return (EINVAL);
+}
+
+struct madvise_args {
+	caddr_t	addr;
+	int	len;
+	int	behav;
+};
+/* ARGSUSED */
+int
+madvise(p, uap, retval)
+	struct proc *p;
+	struct madvise_args *uap;
+	int *retval;
+{
+
+	/* Not yet implemented */
+	return (EOPNOTSUPP);
+}
+
+struct mincore_args {
+	caddr_t	addr;
+	int	len;
+	char	*vec;
+};
+/* ARGSUSED */
+int
+mincore(p, uap, retval)
+	struct proc *p;
+	struct mincore_args *uap;
+	int *retval;
+{
+
+	/* Not yet implemented */
+	return (EOPNOTSUPP);
+}
+
+struct mlock_args {
+	caddr_t	addr;
+	size_t	len;
+};
+int
+mlock(p, uap, retval)
+	struct proc *p;
+	struct mlock_args *uap;
+	int *retval;
+{
+	vm_offset_t addr;
+	vm_size_t size;
+	int error;
+	extern int vm_page_max_wired;
+
+#ifdef DEBUG
+	if (mmapdebug & MDB_FOLLOW)
+		printf("mlock(%d): addr %x len %x\n",
+		       p->p_pid, uap->addr, uap->len);
+#endif
+	addr = (vm_offset_t)uap->addr;
+	if ((addr & PAGE_MASK) || uap->addr + uap->len < uap->addr)
+		return (EINVAL);
+	size = round_page((vm_size_t)uap->len);
+	if (atop(size) + cnt.v_wire_count > vm_page_max_wired)
+		return (EAGAIN);
+#ifdef pmap_wired_count
+	if (size + ptoa(pmap_wired_count(vm_map_pmap(&p->p_vmspace->vm_map))) >
+	    p->p_rlimit[RLIMIT_MEMLOCK].rlim_cur)
+		return (EAGAIN);
+#else
+	if (error = suser(p->p_ucred, &p->p_acflag))
+		return (error);
+#endif
+
+	error = vm_map_pageable(&p->p_vmspace->vm_map, addr, addr+size, FALSE);
+	return (error == KERN_SUCCESS ? 0 : ENOMEM);
+}
+
+struct munlock_args {
+	caddr_t	addr;
+	size_t	len;
+};
+int
+munlock(p, uap, retval)
+	struct proc *p;
+	struct munlock_args *uap;
+	int *retval;
+{
+	vm_offset_t addr;
+	vm_size_t size;
+	int error;
+
+#ifdef DEBUG
+	if (mmapdebug & MDB_FOLLOW)
+		printf("munlock(%d): addr %x len %x\n",
+		       p->p_pid, uap->addr, uap->len);
+#endif
+	addr = (vm_offset_t)uap->addr;
+	if ((addr & PAGE_MASK) || uap->addr + uap->len < uap->addr)
+		return (EINVAL);
+#ifndef pmap_wired_count
+	if (error = suser(p->p_ucred, &p->p_acflag))
+		return (error);
+#endif
+	size = round_page((vm_size_t)uap->len);
+
+	error = vm_map_pageable(&p->p_vmspace->vm_map, addr, addr+size, TRUE);
+	return (error == KERN_SUCCESS ? 0 : ENOMEM);
+}
+
+/*
+ * Internal version of mmap.
+ * Currently used by mmap, exec, and sys5 shared memory.
+ * Handle is either a vnode pointer or NULL for MAP_ANON.
+ */
+int
+vm_mmap(map, addr, size, prot, maxprot, flags, handle, foff)
+	register vm_map_t map;
+	register vm_offset_t *addr;
+	register vm_size_t size;
+	vm_prot_t prot, maxprot;
+	register int flags;
+	caddr_t handle;		/* XXX should be vp */
+	vm_offset_t foff;
+{
+	register vm_pager_t pager;
+	boolean_t fitit;
+	vm_object_t object;
+	struct vnode *vp = NULL;
+	int type;
+	int rv = KERN_SUCCESS;
+
+	if (size == 0)
+		return (0);
+
+	if ((flags & MAP_FIXED) == 0) {
+		fitit = TRUE;
+		*addr = round_page(*addr);
+	} else {
+		fitit = FALSE;
+		(void)vm_deallocate(map, *addr, size);
+	}
+
+	/*
+	 * Lookup/allocate pager.  All except an unnamed anonymous lookup
+	 * gain a reference to ensure continued existance of the object.
+	 * (XXX the exception is to appease the pageout daemon)
+	 */
+	if (flags & MAP_ANON)
+		type = PG_DFLT;
+	else {
+		vp = (struct vnode *)handle;
+		if (vp->v_type == VCHR) {
+			type = PG_DEVICE;
+			handle = (caddr_t)vp->v_rdev;
+		} else
+			type = PG_VNODE;
+	}
+	pager = vm_pager_allocate(type, handle, size, prot, foff);
+	if (pager == NULL)
+		return (type == PG_DEVICE ? EINVAL : ENOMEM);
+	/*
+	 * Find object and release extra reference gained by lookup
+	 */
+	object = vm_object_lookup(pager);
+	vm_object_deallocate(object);
+
+	/*
+	 * Anonymous memory.
+	 */
+	if (flags & MAP_ANON) {
+		rv = vm_allocate_with_pager(map, addr, size, fitit,
+					    pager, foff, TRUE);
+		if (rv != KERN_SUCCESS) {
+			if (handle == NULL)
+				vm_pager_deallocate(pager);
+			else
+				vm_object_deallocate(object);
+			goto out;
+		}
+		/*
+		 * Don't cache anonymous objects.
+		 * Loses the reference gained by vm_pager_allocate.
+		 * Note that object will be NULL when handle == NULL,
+		 * this is ok since vm_allocate_with_pager has made
+		 * sure that these objects are uncached.
+		 */
+		(void) pager_cache(object, FALSE);
+#ifdef DEBUG
+		if (mmapdebug & MDB_MAPIT)
+			printf("vm_mmap(%d): ANON *addr %x size %x pager %x\n",
+			       curproc->p_pid, *addr, size, pager);
+#endif
+	}
+	/*
+	 * Must be a mapped file.
+	 * Distinguish between character special and regular files.
+	 */
+	else if (vp->v_type == VCHR) {
+		rv = vm_allocate_with_pager(map, addr, size, fitit,
+					    pager, foff, FALSE);
+		/*
+		 * Uncache the object and lose the reference gained
+		 * by vm_pager_allocate().  If the call to
+		 * vm_allocate_with_pager() was sucessful, then we
+		 * gained an additional reference ensuring the object
+		 * will continue to exist.  If the call failed then
+		 * the deallocate call below will terminate the
+		 * object which is fine.
+		 */
+		(void) pager_cache(object, FALSE);
+		if (rv != KERN_SUCCESS)
+			goto out;
+	}
+	/*
+	 * A regular file
+	 */
+	else {
+#ifdef DEBUG
+		if (object == NULL)
+			printf("vm_mmap: no object: vp %x, pager %x\n",
+			       vp, pager);
+#endif
+		/*
+		 * Map it directly.
+		 * Allows modifications to go out to the vnode.
+		 */
+		if (flags & MAP_SHARED) {
+			rv = vm_allocate_with_pager(map, addr, size,
+						    fitit, pager,
+						    foff, FALSE);
+			if (rv != KERN_SUCCESS) {
+				vm_object_deallocate(object);
+				goto out;
+			}
+			/*
+			 * Don't cache the object.  This is the easiest way
+			 * of ensuring that data gets back to the filesystem
+			 * because vnode_pager_deallocate() will fsync the
+			 * vnode.  pager_cache() will lose the extra ref.
+			 */
+			if (prot & VM_PROT_WRITE)
+				pager_cache(object, FALSE);
+			else
+				vm_object_deallocate(object);
+		}
+		/*
+		 * Copy-on-write of file.  Two flavors.
+		 * MAP_COPY is true COW, you essentially get a snapshot of
+		 * the region at the time of mapping.  MAP_PRIVATE means only
+		 * that your changes are not reflected back to the object.
+		 * Changes made by others will be seen.
+		 */
+		else {
+			vm_map_t tmap;
+			vm_offset_t off;
+
+			/* locate and allocate the target address space */
+			rv = vm_map_find(map, NULL, (vm_offset_t)0,
+					 addr, size, fitit);
+			if (rv != KERN_SUCCESS) {
+				vm_object_deallocate(object);
+				goto out;
+			}
+			tmap = vm_map_create(pmap_create(size), VM_MIN_ADDRESS,
+					     VM_MIN_ADDRESS+size, TRUE);
+			off = VM_MIN_ADDRESS;
+			rv = vm_allocate_with_pager(tmap, &off, size,
+						    TRUE, pager,
+						    foff, FALSE);
+			if (rv != KERN_SUCCESS) {
+				vm_object_deallocate(object);
+				vm_map_deallocate(tmap);
+				goto out;
+			}
+			/*
+			 * (XXX)
+			 * MAP_PRIVATE implies that we see changes made by
+			 * others.  To ensure that we need to guarentee that
+			 * no copy object is created (otherwise original
+			 * pages would be pushed to the copy object and we
+			 * would never see changes made by others).  We
+			 * totally sleeze it right now by marking the object
+			 * internal temporarily.
+			 */
+			if ((flags & MAP_COPY) == 0)
+				object->flags |= OBJ_INTERNAL;
+			rv = vm_map_copy(map, tmap, *addr, size, off,
+					 FALSE, FALSE);
+			object->flags &= ~OBJ_INTERNAL;
+			/*
+			 * (XXX)
+			 * My oh my, this only gets worse...
+			 * Force creation of a shadow object so that
+			 * vm_map_fork will do the right thing.
+			 */
+			if ((flags & MAP_COPY) == 0) {
+				vm_map_t tmap;
+				vm_map_entry_t tentry;
+				vm_object_t tobject;
+				vm_offset_t toffset;
+				vm_prot_t tprot;
+				boolean_t twired, tsu;
+
+				tmap = map;
+				vm_map_lookup(&tmap, *addr, VM_PROT_WRITE,
+					      &tentry, &tobject, &toffset,
+					      &tprot, &twired, &tsu);
+				vm_map_lookup_done(tmap, tentry);
+			}
+			/*
+			 * (XXX)
+			 * Map copy code cannot detect sharing unless a
+			 * sharing map is involved.  So we cheat and write
+			 * protect everything ourselves.
+			 */
+			vm_object_pmap_copy(object, foff, foff + size);
+			vm_object_deallocate(object);
+			vm_map_deallocate(tmap);
+			if (rv != KERN_SUCCESS)
+				goto out;
+		}
+#ifdef DEBUG
+		if (mmapdebug & MDB_MAPIT)
+			printf("vm_mmap(%d): FILE *addr %x size %x pager %x\n",
+			       curproc->p_pid, *addr, size, pager);
+#endif
+	}
+	/*
+	 * Correct protection (default is VM_PROT_ALL).
+	 * If maxprot is different than prot, we must set both explicitly.
+	 */
+	rv = KERN_SUCCESS;
+	if (maxprot != VM_PROT_ALL)
+		rv = vm_map_protect(map, *addr, *addr+size, maxprot, TRUE);
+	if (rv == KERN_SUCCESS && prot != maxprot)
+		rv = vm_map_protect(map, *addr, *addr+size, prot, FALSE);
+	if (rv != KERN_SUCCESS) {
+		(void) vm_deallocate(map, *addr, size);
+		goto out;
+	}
+	/*
+	 * Shared memory is also shared with children.
+	 */
+	if (flags & MAP_SHARED) {
+		rv = vm_map_inherit(map, *addr, *addr+size, VM_INHERIT_SHARE);
+		if (rv != KERN_SUCCESS) {
+			(void) vm_deallocate(map, *addr, size);
+			goto out;
+		}
+	}
+out:
+#ifdef DEBUG
+	if (mmapdebug & MDB_MAPIT)
+		printf("vm_mmap: rv %d\n", rv);
+#endif
+	switch (rv) {
+	case KERN_SUCCESS:
+		return (0);
+	case KERN_INVALID_ADDRESS:
+	case KERN_NO_SPACE:
+		return (ENOMEM);
+	case KERN_PROTECTION_FAILURE:
+		return (EACCES);
+	default:
+		return (EINVAL);
+	}
+}
diff --git a/sys/vm/vm_object.c b/sys/vm/vm_object.c
new file mode 100644
index 0000000..d11fa8b
--- /dev/null
+++ b/sys/vm/vm_object.c
@@ -0,0 +1,1436 @@
+/* 
+ * Copyright (c) 1991, 1993
+ *	The Regents of the University of California.  All rights reserved.
+ *
+ * This code is derived from software contributed to Berkeley by
+ * The Mach Operating System project at Carnegie-Mellon University.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. All advertising materials mentioning features or use of this software
+ *    must display the following acknowledgement:
+ *	This product includes software developed by the University of
+ *	California, Berkeley and its contributors.
+ * 4. Neither the name of the University nor the names of its contributors
+ *    may be used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ *
+ *	@(#)vm_object.c	8.5 (Berkeley) 3/22/94
+ *
+ *
+ * Copyright (c) 1987, 1990 Carnegie-Mellon University.
+ * All rights reserved.
+ *
+ * Authors: Avadis Tevanian, Jr., Michael Wayne Young
+ * 
+ * Permission to use, copy, modify and distribute this software and
+ * its documentation is hereby granted, provided that both the copyright
+ * notice and this permission notice appear in all copies of the
+ * software, derivative works or modified versions, and any portions
+ * thereof, and that both notices appear in supporting documentation.
+ * 
+ * CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS" 
+ * CONDITION.  CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND 
+ * FOR ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
+ * 
+ * Carnegie Mellon requests users of this software to return to
+ *
+ *  Software Distribution Coordinator  or  Software.Distribution@CS.CMU.EDU
+ *  School of Computer Science
+ *  Carnegie Mellon University
+ *  Pittsburgh PA 15213-3890
+ *
+ * any improvements or extensions that they make and grant Carnegie the
+ * rights to redistribute these changes.
+ */
+
+/*
+ *	Virtual memory object module.
+ */
+
+#include <sys/param.h>
+#include <sys/systm.h>
+#include <sys/malloc.h>
+
+#include <vm/vm.h>
+#include <vm/vm_page.h>
+
+/*
+ *	Virtual memory objects maintain the actual data
+ *	associated with allocated virtual memory.  A given
+ *	page of memory exists within exactly one object.
+ *
+ *	An object is only deallocated when all "references"
+ *	are given up.  Only one "reference" to a given
+ *	region of an object should be writeable.
+ *
+ *	Associated with each object is a list of all resident
+ *	memory pages belonging to that object; this list is
+ *	maintained by the "vm_page" module, and locked by the object's
+ *	lock.
+ *
+ *	Each object also records a "pager" routine which is
+ *	used to retrieve (and store) pages to the proper backing
+ *	storage.  In addition, objects may be backed by other
+ *	objects from which they were virtual-copied.
+ *
+ *	The only items within the object structure which are
+ *	modified after time of creation are:
+ *		reference count		locked by object's lock
+ *		pager routine		locked by object's lock
+ *
+ */
+
+struct vm_object	kernel_object_store;
+struct vm_object	kmem_object_store;
+
+#define	VM_OBJECT_HASH_COUNT	157
+
+int	vm_cache_max = 100;	/* can patch if necessary */
+struct	vm_object_hash_head vm_object_hashtable[VM_OBJECT_HASH_COUNT];
+
+long	object_collapses = 0;
+long	object_bypasses  = 0;
+
+static void _vm_object_allocate __P((vm_size_t, vm_object_t));
+
+/*
+ *	vm_object_init:
+ *
+ *	Initialize the VM objects module.
+ */
+void vm_object_init(size)
+	vm_size_t	size;
+{
+	register int	i;
+
+	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);
+
+	for (i = 0; i < VM_OBJECT_HASH_COUNT; i++)
+		TAILQ_INIT(&vm_object_hashtable[i]);
+
+	kernel_object = &kernel_object_store;
+	_vm_object_allocate(size, kernel_object);
+
+	kmem_object = &kmem_object_store;
+	_vm_object_allocate(VM_KMEM_SIZE + VM_MBUF_SIZE, kmem_object);
+}
+
+/*
+ *	vm_object_allocate:
+ *
+ *	Returns a new object with the given size.
+ */
+
+vm_object_t vm_object_allocate(size)
+	vm_size_t	size;
+{
+	register vm_object_t	result;
+
+	result = (vm_object_t)
+		malloc((u_long)sizeof *result, M_VMOBJ, M_WAITOK);
+
+	_vm_object_allocate(size, result);
+
+	return(result);
+}
+
+static void
+_vm_object_allocate(size, object)
+	vm_size_t		size;
+	register vm_object_t	object;
+{
+	TAILQ_INIT(&object->memq);
+	vm_object_lock_init(object);
+	object->ref_count = 1;
+	object->resident_page_count = 0;
+	object->size = size;
+	object->flags = OBJ_INTERNAL;	/* vm_allocate_with_pager will reset */
+	object->paging_in_progress = 0;
+	object->copy = NULL;
+
+	/*
+	 *	Object starts out read-write, with no pager.
+	 */
+
+	object->pager = NULL;
+	object->paging_offset = 0;
+	object->shadow = NULL;
+	object->shadow_offset = (vm_offset_t) 0;
+
+	simple_lock(&vm_object_list_lock);
+	TAILQ_INSERT_TAIL(&vm_object_list, object, object_list);
+	vm_object_count++;
+	cnt.v_nzfod += atop(size);
+	simple_unlock(&vm_object_list_lock);
+}
+
+/*
+ *	vm_object_reference:
+ *
+ *	Gets another reference to the given object.
+ */
+void vm_object_reference(object)
+	register vm_object_t	object;
+{
+	if (object == NULL)
+		return;
+
+	vm_object_lock(object);
+	object->ref_count++;
+	vm_object_unlock(object);
+}
+
+/*
+ *	vm_object_deallocate:
+ *
+ *	Release a reference to the specified object,
+ *	gained either through a vm_object_allocate
+ *	or a vm_object_reference call.  When all references
+ *	are gone, storage associated with this object
+ *	may be relinquished.
+ *
+ *	No object may be locked.
+ */
+void vm_object_deallocate(object)
+	register vm_object_t	object;
+{
+	vm_object_t	temp;
+
+	while (object != NULL) {
+
+		/*
+		 *	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);
+		if (--(object->ref_count) != 0) {
+
+			/*
+			 *	If there are still references, then
+			 *	we are done.
+			 */
+			vm_object_unlock(object);
+			vm_object_cache_unlock();
+			return;
+		}
+
+		/*
+		 *	See if this object can persist.  If so, enter
+		 *	it in the cache, then deactivate all of its
+		 *	pages.
+		 */
+
+		if (object->flags & OBJ_CANPERSIST) {
+
+			TAILQ_INSERT_TAIL(&vm_object_cached_list, object,
+				cached_list);
+			vm_object_cached++;
+			vm_object_cache_unlock();
+
+			vm_object_deactivate_pages(object);
+			vm_object_unlock(object);
+
+			vm_object_cache_trim();
+			return;
+		}
+
+		/*
+		 *	Make sure no one can look us up now.
+		 */
+		vm_object_remove(object->pager);
+		vm_object_cache_unlock();
+
+		temp = object->shadow;
+		vm_object_terminate(object);
+			/* unlocks and deallocates object */
+		object = temp;
+	}
+}
+
+
+/*
+ *	vm_object_terminate actually destroys the specified object, freeing
+ *	up all previously used resources.
+ *
+ *	The object must be locked.
+ */
+void vm_object_terminate(object)
+	register vm_object_t	object;
+{
+	register vm_page_t	p;
+	vm_object_t		shadow_object;
+
+	/*
+	 *	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;
+#if 0
+		else if (shadow_object->copy != NULL)
+			panic("vm_object_terminate: copy/shadow inconsistency");
+#endif
+		vm_object_unlock(shadow_object);
+	}
+
+	/*
+	 * Wait until the pageout daemon is through with the object.
+	 */
+	while (object->paging_in_progress) {
+		vm_object_sleep((int)object, object, FALSE);
+		vm_object_lock(object);
+	}
+
+	/*
+	 * If not an internal object clean all the pages, removing them
+	 * from paging queues as we go.
+	 *
+	 * XXX need to do something in the event of a cleaning error.
+	 */
+	if ((object->flags & OBJ_INTERNAL) == 0) {
+		(void) vm_object_page_clean(object, 0, 0, TRUE, TRUE);
+		vm_object_unlock(object);
+	}
+
+	/*
+	 * Now free the pages.
+	 * For internal objects, this also removes them from paging queues.
+	 */
+	while ((p = object->memq.tqh_first) != NULL) {
+		VM_PAGE_CHECK(p);
+		vm_page_lock_queues();
+		vm_page_free(p);
+		cnt.v_pfree++;
+		vm_page_unlock_queues();
+	}
+	if ((object->flags & OBJ_INTERNAL) == 0)
+		vm_object_unlock(object);
+
+	/*
+	 * Let the pager know object is dead.
+	 */
+	if (object->pager != NULL)
+		vm_pager_deallocate(object->pager);
+
+	simple_lock(&vm_object_list_lock);
+	TAILQ_REMOVE(&vm_object_list, object, object_list);
+	vm_object_count--;
+	simple_unlock(&vm_object_list_lock);
+
+	/*
+	 * Free the space for the object.
+	 */
+	free((caddr_t)object, M_VMOBJ);
+}
+
+/*
+ *	vm_object_page_clean
+ *
+ *	Clean all dirty pages in the specified range of object.
+ *	If syncio is TRUE, page cleaning is done synchronously.
+ *	If de_queue is TRUE, pages are removed from any paging queue
+ *	they were on, otherwise they are left on whatever queue they
+ *	were on before the cleaning operation began.
+ *
+ *	Odd semantics: if start == end, we clean everything.
+ *
+ *	The object must be locked.
+ *
+ *	Returns TRUE if all was well, FALSE if there was a pager error
+ *	somewhere.  We attempt to clean (and dequeue) all pages regardless
+ *	of where an error occurs.
+ */
+boolean_t
+vm_object_page_clean(object, start, end, syncio, de_queue)
+	register vm_object_t	object;
+	register vm_offset_t	start;
+	register vm_offset_t	end;
+	boolean_t		syncio;
+	boolean_t		de_queue;
+{
+	register vm_page_t	p;
+	int onqueue;
+	boolean_t noerror = TRUE;
+
+	if (object == NULL)
+		return (TRUE);
+
+	/*
+	 * If it is an internal object and there is no pager, attempt to
+	 * allocate one.  Note that vm_object_collapse may relocate one
+	 * from a collapsed object so we must recheck afterward.
+	 */
+	if ((object->flags & OBJ_INTERNAL) && object->pager == NULL) {
+		vm_object_collapse(object);
+		if (object->pager == NULL) {
+			vm_pager_t pager;
+
+			vm_object_unlock(object);
+			pager = vm_pager_allocate(PG_DFLT, (caddr_t)0,
+						  object->size, VM_PROT_ALL,
+						  (vm_offset_t)0);
+			if (pager)
+				vm_object_setpager(object, pager, 0, FALSE);
+			vm_object_lock(object);
+		}
+	}
+	if (object->pager == NULL)
+		return (FALSE);
+
+again:
+	/*
+	 * Wait until the pageout daemon is through with the object.
+	 */
+	while (object->paging_in_progress) {
+		vm_object_sleep((int)object, object, FALSE);
+		vm_object_lock(object);
+	}
+	/*
+	 * Loop through the object page list cleaning as necessary.
+	 */
+	for (p = object->memq.tqh_first; p != NULL; p = p->listq.tqe_next) {
+		if ((start == end || p->offset >= start && p->offset < end) &&
+		    !(p->flags & PG_FICTITIOUS)) {
+			if ((p->flags & PG_CLEAN) &&
+			    pmap_is_modified(VM_PAGE_TO_PHYS(p)))
+				p->flags &= ~PG_CLEAN;
+			/*
+			 * Remove the page from any paging queue.
+			 * This needs to be done if either we have been
+			 * explicitly asked to do so or it is about to
+			 * be cleaned (see comment below).
+			 */
+			if (de_queue || !(p->flags & PG_CLEAN)) {
+				vm_page_lock_queues();
+				if (p->flags & PG_ACTIVE) {
+					TAILQ_REMOVE(&vm_page_queue_active,
+						     p, pageq);
+					p->flags &= ~PG_ACTIVE;
+					cnt.v_active_count--;
+					onqueue = 1;
+				} else if (p->flags & PG_INACTIVE) {
+					TAILQ_REMOVE(&vm_page_queue_inactive,
+						     p, pageq);
+					p->flags &= ~PG_INACTIVE;
+					cnt.v_inactive_count--;
+					onqueue = -1;
+				} else
+					onqueue = 0;
+				vm_page_unlock_queues();
+			}
+			/*
+			 * To ensure the state of the page doesn't change
+			 * during the clean operation we do two things.
+			 * First we set the busy bit and write-protect all
+			 * mappings to ensure that write accesses to the
+			 * page block (in vm_fault).  Second, we remove
+			 * the page from any paging queue to foil the
+			 * pageout daemon (vm_pageout_scan).
+			 */
+			pmap_page_protect(VM_PAGE_TO_PHYS(p), VM_PROT_READ);
+			if (!(p->flags & PG_CLEAN)) {
+				p->flags |= PG_BUSY;
+				object->paging_in_progress++;
+				vm_object_unlock(object);
+				/*
+				 * XXX if put fails we mark the page as
+				 * clean to avoid an infinite loop.
+				 * Will loose changes to the page.
+				 */
+				if (vm_pager_put(object->pager, p, syncio)) {
+					printf("%s: pager_put error\n",
+					       "vm_object_page_clean");
+					p->flags |= PG_CLEAN;
+					noerror = FALSE;
+				}
+				vm_object_lock(object);
+				object->paging_in_progress--;
+				if (!de_queue && onqueue) {
+					vm_page_lock_queues();
+					if (onqueue > 0)
+						vm_page_activate(p);
+					else
+						vm_page_deactivate(p);
+					vm_page_unlock_queues();
+				}
+				p->flags &= ~PG_BUSY;
+				PAGE_WAKEUP(p);
+				goto again;
+			}
+		}
+	}
+	return (noerror);
+}
+
+/*
+ *	vm_object_deactivate_pages
+ *
+ *	Deactivate all pages in the specified object.  (Keep its pages
+ *	in memory even though it is no longer referenced.)
+ *
+ *	The object must be locked.
+ */
+void
+vm_object_deactivate_pages(object)
+	register vm_object_t	object;
+{
+	register vm_page_t	p, next;
+
+	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();
+	}
+}
+
+/*
+ *	Trim the object cache to size.
+ */
+void
+vm_object_cache_trim()
+{
+	register vm_object_t	object;
+
+	vm_object_cache_lock();
+	while (vm_object_cached > vm_cache_max) {
+		object = vm_object_cached_list.tqh_first;
+		vm_object_cache_unlock();
+
+		if (object != vm_object_lookup(object->pager))
+			panic("vm_object_deactivate: I'm sooo confused.");
+
+		pager_cache(object, FALSE);
+
+		vm_object_cache_lock();
+	}
+	vm_object_cache_unlock();
+}
+
+/*
+ *	vm_object_pmap_copy:
+ *
+ *	Makes all physical pages in the specified
+ *	object range copy-on-write.  No writeable
+ *	references to these pages should remain.
+ *
+ *	The object must *not* be locked.
+ */
+void vm_object_pmap_copy(object, start, end)
+	register vm_object_t	object;
+	register vm_offset_t	start;
+	register vm_offset_t	end;
+{
+	register vm_page_t	p;
+
+	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)) {
+			pmap_page_protect(VM_PAGE_TO_PHYS(p), VM_PROT_READ);
+			p->flags |= PG_COPYONWRITE;
+		}
+	}
+	vm_object_unlock(object);
+}
+
+/*
+ *	vm_object_pmap_remove:
+ *
+ *	Removes all physical pages in the specified
+ *	object range from all physical maps.
+ *
+ *	The object must *not* be locked.
+ */
+void vm_object_pmap_remove(object, start, end)
+	register vm_object_t	object;
+	register vm_offset_t	start;
+	register vm_offset_t	end;
+{
+	register vm_page_t	p;
+
+	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))
+			pmap_page_protect(VM_PAGE_TO_PHYS(p), VM_PROT_NONE);
+	vm_object_unlock(object);
+}
+
+/*
+ *	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, size,
+		    dst_object, dst_offset, src_needs_copy)
+	register vm_object_t	src_object;
+	vm_offset_t		src_offset;
+	vm_size_t		size;
+	vm_object_t		*dst_object;	/* OUT */
+	vm_offset_t		*dst_offset;	/* OUT */
+	boolean_t		*src_needs_copy;	/* OUT */
+{
+	register vm_object_t	new_copy;
+	register vm_object_t	old_copy;
+	vm_offset_t		new_start, new_end;
+
+	register vm_page_t	p;
+
+	if (src_object == NULL) {
+		/*
+		 *	Nothing to copy
+		 */
+		*dst_object = NULL;
+		*dst_offset = 0;
+		*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);
+	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;
+	}
+
+	/*
+	 *	Try to collapse the object before copying it.
+	 */
+	vm_object_collapse(src_object);
+
+	/*
+	 *	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... */
+			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);
+			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 */
+		old_copy->shadow = new_copy;
+		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.
+	 */
+
+	new_copy->shadow = src_object;
+	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.
+	 */
+	for (p = src_object->memq.tqh_first; p != NULL; p = p->listq.tqe_next)
+		if ((new_start <= p->offset) && (p->offset < new_end))
+			p->flags |= PG_COPYONWRITE;
+
+	vm_object_unlock(src_object);
+
+	*dst_object = new_copy;
+	*dst_offset = src_offset - new_start;
+	*src_needs_copy = FALSE;
+}
+
+/*
+ *	vm_object_shadow:
+ *
+ *	Create a new object which is backed by the
+ *	specified existing object range.  The source
+ *	object reference is deallocated.
+ *
+ *	The new object and offset into that object
+ *	are returned in the source parameters.
+ */
+
+void vm_object_shadow(object, offset, length)
+	vm_object_t	*object;	/* IN/OUT */
+	vm_offset_t	*offset;	/* IN/OUT */
+	vm_size_t	length;
+{
+	register vm_object_t	source;
+	register vm_object_t	result;
+
+	source = *object;
+
+	/*
+	 *	Allocate a new object with the given length
+	 */
+
+	if ((result = vm_object_allocate(length)) == NULL)
+		panic("vm_object_shadow: no object for shadowing");
+
+	/*
+	 *	The new object shadows the source object, adding
+	 *	a reference to it.  Our caller changes his reference
+	 *	to point to the new object, removing a reference to
+	 *	the source object.  Net result: no change of reference
+	 *	count.
+	 */
+	result->shadow = source;
+	
+	/*
+	 *	Store the offset into the source object,
+	 *	and fix up the offset into the new object.
+	 */
+
+	result->shadow_offset = *offset;
+
+	/*
+	 *	Return the new things
+	 */
+
+	*offset = 0;
+	*object = result;
+}
+
+/*
+ *	Set the specified object's pager to the specified pager.
+ */
+
+void vm_object_setpager(object, pager, paging_offset,
+			read_only)
+	vm_object_t	object;
+	vm_pager_t	pager;
+	vm_offset_t	paging_offset;
+	boolean_t	read_only;
+{
+#ifdef	lint
+	read_only++;	/* No longer used */
+#endif
+
+	vm_object_lock(object);			/* XXX ? */
+	object->pager = pager;
+	object->paging_offset = paging_offset;
+	vm_object_unlock(object);			/* XXX ? */
+}
+
+/*
+ *	vm_object_hash hashes the pager/id pair.
+ */
+
+#define vm_object_hash(pager) \
+	(((unsigned)pager)%VM_OBJECT_HASH_COUNT)
+
+/*
+ *	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[vm_object_hash(pager)].tqh_first;
+	     entry != NULL;
+	     entry = entry->hash_links.tqe_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[vm_object_hash(pager)];
+	entry = (vm_object_hash_entry_t)
+		malloc((u_long)sizeof *entry, M_VMOBJHASH, M_WAITOK);
+	entry->object = object;
+	object->flags |= OBJ_CANPERSIST;
+
+	vm_object_cache_lock();
+	TAILQ_INSERT_TAIL(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[vm_object_hash(pager)];
+
+	for (entry = bucket->tqh_first;
+	     entry != NULL;
+	     entry = entry->hash_links.tqe_next) {
+		object = entry->object;
+		if (object->pager == pager) {
+			TAILQ_REMOVE(bucket, entry, hash_links);
+			free((caddr_t)entry, M_VMOBJHASH);
+			break;
+		}
+	}
+}
+
+/*
+ *	vm_object_cache_clear removes all objects from the cache.
+ *
+ */
+
+void vm_object_cache_clear()
+{
+	register vm_object_t	object;
+
+	/*
+	 *	Remove each object in the cache by scanning down the
+	 *	list of cached objects.
+	 */
+	vm_object_cache_lock();
+	while ((object = vm_object_cached_list.tqh_first) != NULL) {
+		vm_object_cache_unlock();
+
+		/* 
+		 * Note: it is important that we use vm_object_lookup
+		 * to gain a reference, and not vm_object_reference, because
+		 * the logic for removing an object from the cache lies in 
+		 * lookup.
+		 */
+		if (object != vm_object_lookup(object->pager))
+			panic("vm_object_cache_clear: I'm sooo confused.");
+		pager_cache(object, FALSE);
+
+		vm_object_cache_lock();
+	}
+	vm_object_cache_unlock();
+}
+
+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.
+ *
+ */
+void vm_object_collapse(object)
+	register 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;
+
+	while (TRUE) {
+		/*
+		 *	Verify that the conditions are right for collapse:
+		 *
+		 *	The object exists and no pages in it are currently
+		 *	being paged out (or have ever been paged out).
+		 */
+		if (object == NULL ||
+		    object->paging_in_progress != 0 ||
+		    object->pager != NULL)
+			return;
+
+		/*
+		 *		There is a backing object, and
+		 */
+	
+		if ((backing_object = object->shadow) == NULL)
+			return;
+	
+		vm_object_lock(backing_object);
+		/*
+		 *	...
+		 *		The backing object is not read_only,
+		 *		and no pages in the backing object are
+		 *		currently being paged out.
+		 *		The backing object is internal.
+		 */
+	
+		if ((backing_object->flags & OBJ_INTERNAL) == 0 ||
+		    backing_object->paging_in_progress != 0) {
+			vm_object_unlock(backing_object);
+			return;
+		}
+	
+		/*
+		 *	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 != NULL) {
+			vm_object_unlock(backing_object);
+			return;
+		}
+
+		/*
+		 *	We know that we can either collapse the backing
+		 *	object (if the parent is the only reference to
+		 *	it) or (perhaps) remove the parent's reference
+		 *	to it.
+		 */
+
+		backing_offset = object->shadow_offset;
+		size = object->size;
+
+		/*
+		 *	If there is exactly one reference to the backing
+		 *	object, we can collapse it into the parent.
+		 */
+	
+		if (backing_object->ref_count == 1) {
+
+			/*
+			 *	We can collapse the backing object.
+			 *
+			 *	Move all in-memory pages from backing_object
+			 *	to the parent.  Pages that have been paged out
+			 *	will be overwritten by any of the parent's
+			 *	pages that shadow them.
+			 */
+
+			while ((p = backing_object->memq.tqh_first) != NULL) {
+				new_offset = (p->offset - backing_offset);
+
+				/*
+				 *	If the parent has a page here, or if
+				 *	this page falls outside the parent,
+				 *	dispose of it.
+				 *
+				 *	Otherwise, move it as planned.
+				 */
+
+				if (p->offset < backing_offset ||
+				    new_offset >= size) {
+					vm_page_lock_queues();
+					vm_page_free(p);
+					vm_page_unlock_queues();
+				} else {
+				    pp = vm_page_lookup(object, new_offset);
+				    if (pp != NULL && !(pp->flags & PG_FAKE)) {
+					vm_page_lock_queues();
+					vm_page_free(p);
+					vm_page_unlock_queues();
+				    }
+				    else {
+					if (pp) {
+					    /* may be someone waiting for it */
+					    PAGE_WAKEUP(pp);
+					    vm_page_lock_queues();
+					    vm_page_free(pp);
+					    vm_page_unlock_queues();
+					}
+					vm_page_rename(p, object, new_offset);
+				    }
+				}
+			}
+
+			/*
+			 *	Move the pager from backing_object to object.
+			 *
+			 *	XXX We're only using part of the paging space
+			 *	for keeps now... we ought to discard the
+			 *	unused portion.
+			 */
+
+			if (backing_object->pager) {
+				object->pager = backing_object->pager;
+				object->paging_offset = backing_offset +
+					backing_object->paging_offset;
+				backing_object->pager = NULL;
+			}
+
+			/*
+			 *	Object now shadows whatever backing_object did.
+			 *	Note that the reference to backing_object->shadow
+			 *	moves from within backing_object to within object.
+			 */
+
+			object->shadow = backing_object->shadow;
+			object->shadow_offset += backing_object->shadow_offset;
+			if (object->shadow != NULL &&
+			    object->shadow->copy != NULL) {
+				panic("vm_object_collapse: we collapsed a copy-object!");
+			}
+			/*
+			 *	Discard backing_object.
+			 *
+			 *	Since the backing object has no pages, no
+			 *	pager left, and no object references within it,
+			 *	all that is 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);
+
+			object_collapses++;
+		}
+		else {
+			/*
+			 *	If all of the pages in the backing object are
+			 *	shadowed by the parent object, the parent
+			 *	object no longer has to shadow the backing
+			 *	object; it can shadow the next one in the
+			 *	chain.
+			 *
+			 *	The backing object must not be paged out - we'd
+			 *	have to check all of the paged-out pages, as
+			 *	well.
+			 */
+
+			if (backing_object->pager != NULL) {
+				vm_object_unlock(backing_object);
+				return;
+			}
+
+			/*
+			 *	Should have a check for a 'small' number
+			 *	of pages here.
+			 */
+
+			for (p = backing_object->memq.tqh_first;
+			     p != NULL;
+			     p = p->listq.tqe_next) {
+				new_offset = (p->offset - backing_offset);
+
+				/*
+				 *	If the parent has a page here, or if
+				 *	this page falls outside the parent,
+				 *	keep going.
+				 *
+				 *	Otherwise, the backing_object must be
+				 *	left in the chain.
+				 */
+
+				if (p->offset >= backing_offset &&
+				    new_offset < size &&
+				    ((pp = vm_page_lookup(object, new_offset))
+				      == NULL ||
+				     (pp->flags & PG_FAKE))) {
+					/*
+					 *	Page still needed.
+					 *	Can't go any further.
+					 */
+					vm_object_unlock(backing_object);
+					return;
+				}
+			}
+
+			/*
+			 *	Make the parent shadow the next object
+			 *	in the chain.  Deallocating backing_object
+			 *	will not remove it, since its reference
+			 *	count is at least 2.
+			 */
+
+			object->shadow = backing_object->shadow;
+			vm_object_reference(object->shadow);
+			object->shadow_offset += backing_object->shadow_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.
+			 */
+			backing_object->ref_count--;
+			vm_object_unlock(backing_object);
+
+			object_bypasses ++;
+
+		}
+
+		/*
+		 *	Try again with this object's new backing object.
+		 */
+	}
+}
+
+/*
+ *	vm_object_page_remove: [internal]
+ *
+ *	Removes all physical pages in the specified
+ *	object range from the object's list of pages.
+ *
+ *	The object must be locked.
+ */
+void vm_object_page_remove(object, start, end)
+	register vm_object_t	object;
+	register vm_offset_t	start;
+	register vm_offset_t	end;
+{
+	register vm_page_t	p, next;
+
+	if (object == NULL)
+		return;
+
+	for (p = object->memq.tqh_first; p != NULL; p = next) {
+		next = p->listq.tqe_next;
+		if ((start <= p->offset) && (p->offset < end)) {
+			pmap_page_protect(VM_PAGE_TO_PHYS(p), VM_PROT_NONE);
+			vm_page_lock_queues();
+			vm_page_free(p);
+			vm_page_unlock_queues();
+		}
+	}
+}
+
+/*
+ *	Routine:	vm_object_coalesce
+ *	Function:	Coalesces two objects backing up adjoining
+ *			regions of memory into a single object.
+ *
+ *	returns TRUE if objects were combined.
+ *
+ *	NOTE:	Only works at the moment if the second object is NULL -
+ *		if it's not, which object do we lock first?
+ *
+ *	Parameters:
+ *		prev_object	First object to coalesce
+ *		prev_offset	Offset into prev_object
+ *		next_object	Second object into coalesce
+ *		next_offset	Offset into next_object
+ *
+ *		prev_size	Size of reference to prev_object
+ *		next_size	Size of reference to next_object
+ *
+ *	Conditions:
+ *	The object must *not* be locked.
+ */
+boolean_t vm_object_coalesce(prev_object, next_object,
+			prev_offset, next_offset,
+			prev_size, next_size)
+
+	register vm_object_t	prev_object;
+	vm_object_t	next_object;
+	vm_offset_t	prev_offset, next_offset;
+	vm_size_t	prev_size, next_size;
+{
+	vm_size_t	newsize;
+
+#ifdef	lint
+	next_offset++;
+#endif
+
+	if (next_object != NULL) {
+		return(FALSE);
+	}
+
+	if (prev_object == NULL) {
+		return(TRUE);
+	}
+
+	vm_object_lock(prev_object);
+
+	/*
+	 *	Try to collapse the object first
+	 */
+	vm_object_collapse(prev_object);
+
+	/*
+	 *	Can't coalesce if:
+	 *	. more than one reference
+	 *	. paged out
+	 *	. shadows another object
+	 *	. has a copy elsewhere
+	 *	(any of which mean that the pages not mapped to
+	 *	prev_entry may be in use anyway)
+	 */
+
+	if (prev_object->ref_count > 1 ||
+		prev_object->pager != NULL ||
+		prev_object->shadow != NULL ||
+		prev_object->copy != NULL) {
+		vm_object_unlock(prev_object);
+		return(FALSE);
+	}
+
+	/*
+	 *	Remove any pages that may still be in the object from
+	 *	a previous deallocation.
+	 */
+
+	vm_object_page_remove(prev_object,
+			prev_offset + prev_size,
+			prev_offset + prev_size + next_size);
+
+	/*
+	 *	Extend the object if necessary.
+	 */
+	newsize = prev_offset + prev_size + next_size;
+	if (newsize > prev_object->size)
+		prev_object->size = newsize;
+
+	vm_object_unlock(prev_object);
+	return(TRUE);
+}
+
+/*
+ *	vm_object_print:	[ debug ]
+ */
+void vm_object_print(object, full)
+	vm_object_t	object;
+	boolean_t	full;
+{
+	register vm_page_t	p;
+	extern indent;
+
+	register int count;
+
+	if (object == NULL)
+		return;
+
+	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("cache: next=0x%x, prev=0x%x\n",
+	       object->cached_list.tqe_next, object->cached_list.tqe_prev);
+
+	if (!full)
+		return;
+
+	indent += 2;
+	count = 0;
+	for (p = object->memq.tqh_first; p != NULL; p = p->listq.tqe_next) {
+		if (count == 0)
+			iprintf("memory:=");
+		else if (count == 6) {
+			printf("\n");
+			iprintf(" ...");
+			count = 0;
+		} else
+			printf(",");
+		count++;
+
+		printf("(off=0x%x,page=0x%x)", p->offset, VM_PAGE_TO_PHYS(p));
+	}
+	if (count != 0)
+		printf("\n");
+	indent -= 2;
+}
diff --git a/sys/vm/vm_object.h b/sys/vm/vm_object.h
new file mode 100644
index 0000000..5e220ac
--- /dev/null
+++ b/sys/vm/vm_object.h
@@ -0,0 +1,173 @@
+/* 
+ * Copyright (c) 1991, 1993
+ *	The Regents of the University of California.  All rights reserved.
+ *
+ * This code is derived from software contributed to Berkeley by
+ * The Mach Operating System project at Carnegie-Mellon University.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. All advertising materials mentioning features or use of this software
+ *    must display the following acknowledgement:
+ *	This product includes software developed by the University of
+ *	California, Berkeley and its contributors.
+ * 4. Neither the name of the University nor the names of its contributors
+ *    may be used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ *
+ *	@(#)vm_object.h	8.3 (Berkeley) 1/12/94
+ *
+ *
+ * Copyright (c) 1987, 1990 Carnegie-Mellon University.
+ * All rights reserved.
+ *
+ * Authors: Avadis Tevanian, Jr., Michael Wayne Young
+ * 
+ * Permission to use, copy, modify and distribute this software and
+ * its documentation is hereby granted, provided that both the copyright
+ * notice and this permission notice appear in all copies of the
+ * software, derivative works or modified versions, and any portions
+ * thereof, and that both notices appear in supporting documentation.
+ * 
+ * CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS" 
+ * CONDITION.  CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND 
+ * FOR ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
+ * 
+ * Carnegie Mellon requests users of this software to return to
+ *
+ *  Software Distribution Coordinator  or  Software.Distribution@CS.CMU.EDU
+ *  School of Computer Science
+ *  Carnegie Mellon University
+ *  Pittsburgh PA 15213-3890
+ *
+ * any improvements or extensions that they make and grant Carnegie the
+ * rights to redistribute these changes.
+ */
+
+/*
+ *	Virtual memory object module definitions.
+ */
+
+#ifndef	_VM_OBJECT_
+#define	_VM_OBJECT_
+
+#include <vm/vm_page.h>
+#include <vm/vm_pager.h>
+
+/*
+ *	Types defined:
+ *
+ *	vm_object_t		Virtual memory object.
+ */
+
+struct vm_object {
+	struct pglist		memq;		/* Resident memory */
+	TAILQ_ENTRY(vm_object)	object_list;	/* list of all objects */
+	u_short			flags;		/* see below */
+	u_short			paging_in_progress; /* Paging (in or out) so
+						    don't collapse or destroy */
+	simple_lock_data_t	Lock;		/* Synchronization */
+	int			ref_count;	/* How many refs?? */
+	vm_size_t		size;		/* Object size */
+	int			resident_page_count;
+						/* number of resident pages */
+	struct vm_object	*copy;		/* Object that holds copies of
+						   my changed pages */
+	vm_pager_t		pager;		/* Where to get data */
+	vm_offset_t		paging_offset;	/* Offset into paging space */
+	struct vm_object	*shadow;	/* My shadow */
+	vm_offset_t		shadow_offset;	/* Offset in shadow */
+	TAILQ_ENTRY(vm_object)	cached_list;	/* for persistence */
+};
+/*
+ * Flags
+ */
+#define OBJ_CANPERSIST	0x0001	/* allow to persist */
+#define OBJ_INTERNAL	0x0002	/* internally created object */
+#define OBJ_ACTIVE	0x0004	/* used to mark active objects */
+
+TAILQ_HEAD(vm_object_hash_head, vm_object_hash_entry);
+
+struct vm_object_hash_entry {
+	TAILQ_ENTRY(vm_object_hash_entry)  hash_links;	/* hash chain links */
+	vm_object_t			   object;	/* object represened */
+};
+
+typedef struct vm_object_hash_entry	*vm_object_hash_entry_t;
+
+#ifdef	KERNEL
+TAILQ_HEAD(object_q, vm_object);
+
+struct object_q	vm_object_cached_list;	/* list of objects persisting */
+int		vm_object_cached;	/* size of cached list */
+simple_lock_data_t	vm_cache_lock;	/* lock for object cache */
+
+struct object_q	vm_object_list;		/* list of allocated objects */
+long		vm_object_count;	/* count of all objects */
+simple_lock_data_t	vm_object_list_lock;
+					/* lock for object list and count */
+
+vm_object_t	kernel_object;		/* the single kernel object */
+vm_object_t	kmem_object;
+
+#define	vm_object_cache_lock()		simple_lock(&vm_cache_lock)
+#define	vm_object_cache_unlock()	simple_unlock(&vm_cache_lock)
+#endif /* KERNEL */
+
+#define	vm_object_lock_init(object)	simple_lock_init(&(object)->Lock)
+#define	vm_object_lock(object)		simple_lock(&(object)->Lock)
+#define	vm_object_unlock(object)	simple_unlock(&(object)->Lock)
+#define	vm_object_lock_try(object)	simple_lock_try(&(object)->Lock)
+#define	vm_object_sleep(event, object, interruptible) \
+					thread_sleep((event), &(object)->Lock, (interruptible))
+
+#ifdef KERNEL
+vm_object_t	 vm_object_allocate __P((vm_size_t));
+void		 vm_object_cache_clear __P((void));
+void		 vm_object_cache_trim __P((void));
+boolean_t	 vm_object_coalesce __P((vm_object_t, vm_object_t,
+		    vm_offset_t, vm_offset_t, vm_offset_t, vm_size_t));
+void		 vm_object_collapse __P((vm_object_t));
+void		 vm_object_copy __P((vm_object_t, vm_offset_t, vm_size_t,
+		    vm_object_t *, vm_offset_t *, boolean_t *));
+void		 vm_object_deactivate_pages __P((vm_object_t));
+void		 vm_object_deallocate __P((vm_object_t));
+void		 vm_object_enter __P((vm_object_t, vm_pager_t));
+void		 vm_object_init __P((vm_size_t));
+vm_object_t	 vm_object_lookup __P((vm_pager_t));
+boolean_t	 vm_object_page_clean __P((vm_object_t,
+		    vm_offset_t, vm_offset_t, boolean_t, boolean_t));
+void		 vm_object_page_remove __P((vm_object_t,
+		    vm_offset_t, vm_offset_t));
+void		 vm_object_pmap_copy __P((vm_object_t,
+		    vm_offset_t, vm_offset_t));
+void		 vm_object_pmap_remove __P((vm_object_t,
+		    vm_offset_t, vm_offset_t));
+void		 vm_object_print __P((vm_object_t, boolean_t));
+void		 vm_object_reference __P((vm_object_t));
+void		 vm_object_remove __P((vm_pager_t));
+void		 vm_object_setpager __P((vm_object_t,
+		    vm_pager_t, vm_offset_t, boolean_t));
+void		 vm_object_shadow __P((vm_object_t *,
+		    vm_offset_t *, vm_size_t));
+void		 vm_object_terminate __P((vm_object_t));
+#endif
+#endif /* _VM_OBJECT_ */
diff --git a/sys/vm/vm_page.c b/sys/vm/vm_page.c
new file mode 100644
index 0000000..0cd9d87
--- /dev/null
+++ b/sys/vm/vm_page.c
@@ -0,0 +1,696 @@
+/* 
+ * Copyright (c) 1991, 1993
+ *	The Regents of the University of California.  All rights reserved.
+ *
+ * This code is derived from software contributed to Berkeley by
+ * The Mach Operating System project at Carnegie-Mellon University.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. All advertising materials mentioning features or use of this software
+ *    must display the following acknowledgement:
+ *	This product includes software developed by the University of
+ *	California, Berkeley and its contributors.
+ * 4. Neither the name of the University nor the names of its contributors
+ *    may be used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ *
+ *	@(#)vm_page.c	8.3 (Berkeley) 3/21/94
+ *
+ *
+ * Copyright (c) 1987, 1990 Carnegie-Mellon University.
+ * All rights reserved.
+ *
+ * Authors: Avadis Tevanian, Jr., Michael Wayne Young
+ * 
+ * Permission to use, copy, modify and distribute this software and
+ * its documentation is hereby granted, provided that both the copyright
+ * notice and this permission notice appear in all copies of the
+ * software, derivative works or modified versions, and any portions
+ * thereof, and that both notices appear in supporting documentation.
+ * 
+ * CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS" 
+ * CONDITION.  CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND 
+ * FOR ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
+ * 
+ * Carnegie Mellon requests users of this software to return to
+ *
+ *  Software Distribution Coordinator  or  Software.Distribution@CS.CMU.EDU
+ *  School of Computer Science
+ *  Carnegie Mellon University
+ *  Pittsburgh PA 15213-3890
+ *
+ * any improvements or extensions that they make and grant Carnegie the
+ * rights to redistribute these changes.
+ */
+
+/*
+ *	Resident memory management module.
+ */
+
+#include <sys/param.h>
+#include <sys/systm.h>
+
+#include <vm/vm.h>
+#include <vm/vm_page.h>
+#include <vm/vm_map.h>
+#include <vm/vm_pageout.h>
+
+/*
+ *	Associated with page of user-allocatable memory is a
+ *	page structure.
+ */
+
+struct pglist	*vm_page_buckets;		/* Array of buckets */
+int		vm_page_bucket_count = 0;	/* How big is array? */
+int		vm_page_hash_mask;		/* Mask for hash function */
+simple_lock_data_t	bucket_lock;		/* lock for all buckets XXX */
+
+struct pglist	vm_page_queue_free;
+struct pglist	vm_page_queue_active;
+struct pglist	vm_page_queue_inactive;
+simple_lock_data_t	vm_page_queue_lock;
+simple_lock_data_t	vm_page_queue_free_lock;
+
+/* has physical page allocation been initialized? */
+boolean_t vm_page_startup_initialized;
+
+vm_page_t	vm_page_array;
+long		first_page;
+long		last_page;
+vm_offset_t	first_phys_addr;
+vm_offset_t	last_phys_addr;
+vm_size_t	page_mask;
+int		page_shift;
+
+/*
+ *	vm_set_page_size:
+ *
+ *	Sets the page size, perhaps based upon the memory
+ *	size.  Must be called before any use of page-size
+ *	dependent functions.
+ *
+ *	Sets page_shift and page_mask from cnt.v_page_size.
+ */
+void vm_set_page_size()
+{
+
+	if (cnt.v_page_size == 0)
+		cnt.v_page_size = DEFAULT_PAGE_SIZE;
+	page_mask = cnt.v_page_size - 1;
+	if ((page_mask & cnt.v_page_size) != 0)
+		panic("vm_set_page_size: page size not a power of two");
+	for (page_shift = 0; ; page_shift++)
+		if ((1 << page_shift) == cnt.v_page_size)
+			break;
+}
+
+
+/*
+ *	vm_page_startup:
+ *
+ *	Initializes the resident memory module.
+ *
+ *	Allocates memory for the page cells, and
+ *	for the object/offset-to-page hash table headers.
+ *	Each page cell is initialized and placed on the free list.
+ */
+void vm_page_startup(start, end)
+	vm_offset_t	*start;
+	vm_offset_t	*end;
+{
+	register vm_page_t	m;
+	register struct pglist	*bucket;
+	vm_size_t		npages;
+	int			i;
+	vm_offset_t		pa;
+	extern	vm_offset_t	kentry_data;
+	extern	vm_size_t	kentry_data_size;
+
+
+	/*
+	 *	Initialize the locks
+	 */
+
+	simple_lock_init(&vm_page_queue_free_lock);
+	simple_lock_init(&vm_page_queue_lock);
+
+	/*
+	 *	Initialize the queue headers for the free queue,
+	 *	the active queue and the inactive queue.
+	 */
+
+	TAILQ_INIT(&vm_page_queue_free);
+	TAILQ_INIT(&vm_page_queue_active);
+	TAILQ_INIT(&vm_page_queue_inactive);
+
+	/*
+	 *	Calculate the number of hash table buckets.
+	 *
+	 *	The number of buckets MUST BE a power of 2, and
+	 *	the actual value is the next power of 2 greater
+	 *	than the number of physical pages in the system.
+	 *
+	 *	Note:
+	 *		This computation can be tweaked if desired.
+	 */
+
+	if (vm_page_bucket_count == 0) {
+		vm_page_bucket_count = 1;
+		while (vm_page_bucket_count < atop(*end - *start))
+			vm_page_bucket_count <<= 1;
+	}
+
+	vm_page_hash_mask = vm_page_bucket_count - 1;
+
+	/*
+	 *	Allocate (and initialize) the hash table buckets.
+	 */
+	vm_page_buckets = (struct pglist *)
+	    pmap_bootstrap_alloc(vm_page_bucket_count * sizeof(struct pglist));
+	bucket = vm_page_buckets;
+
+	for (i = vm_page_bucket_count; i--;) {
+		TAILQ_INIT(bucket);
+		bucket++;
+	}
+
+	simple_lock_init(&bucket_lock);
+
+	/*
+	 *	Truncate the remainder of physical memory to our page size.
+	 */
+
+	*end = trunc_page(*end);
+
+	/*
+	 *	Pre-allocate maps and map entries that cannot be dynamically
+	 *	allocated via malloc().  The maps include the kernel_map and
+	 *	kmem_map which must be initialized before malloc() will
+	 *	work (obviously).  Also could include pager maps which would
+	 *	be allocated before kmeminit.
+	 *
+	 *	Allow some kernel map entries... this should be plenty
+	 *	since people shouldn't be cluttering up the kernel
+	 *	map (they should use their own maps).
+	 */
+
+	kentry_data_size = round_page(MAX_KMAP*sizeof(struct vm_map) +
+				      MAX_KMAPENT*sizeof(struct vm_map_entry));
+	kentry_data = (vm_offset_t) pmap_bootstrap_alloc(kentry_data_size);
+
+	/*
+ 	 *	Compute the number of pages of memory that will be
+	 *	available for use (taking into account the overhead
+	 *	of a page structure per page).
+	 */
+
+	cnt.v_free_count = npages = (*end - *start + sizeof(struct vm_page))
+		/ (PAGE_SIZE + sizeof(struct vm_page));
+
+	/*
+	 *	Record the extent of physical memory that the
+	 *	virtual memory system manages.
+	 */
+
+	first_page = *start;
+	first_page += npages*sizeof(struct vm_page);
+	first_page = atop(round_page(first_page));
+	last_page  = first_page + npages - 1;
+
+	first_phys_addr = ptoa(first_page);
+	last_phys_addr  = ptoa(last_page) + PAGE_MASK;
+
+
+	/*
+	 *	Allocate and clear the mem entry structures.
+	 */
+
+	m = vm_page_array = (vm_page_t)
+		pmap_bootstrap_alloc(npages * sizeof(struct vm_page));
+
+	/*
+	 *	Initialize the mem entry structures now, and
+	 *	put them in the free queue.
+	 */
+
+	pa = first_phys_addr;
+	while (npages--) {
+		m->flags = 0;
+		m->object = NULL;
+		m->phys_addr = pa;
+#ifdef i386
+		if (pmap_isvalidphys(m->phys_addr)) {
+			TAILQ_INSERT_TAIL(&vm_page_queue_free, m, pageq);
+		} else {
+			/* perhaps iomem needs it's own type, or dev pager? */
+			m->flags |= PG_FICTITIOUS | PG_BUSY;
+			cnt.v_free_count--;
+		}
+#else /* i386 */
+		TAILQ_INSERT_TAIL(&vm_page_queue_free, m, pageq);
+#endif /* i386 */
+		m++;
+		pa += PAGE_SIZE;
+	}
+
+	/*
+	 *	Initialize vm_pages_needed lock here - don't wait for pageout
+	 *	daemon	XXX
+	 */
+	simple_lock_init(&vm_pages_needed_lock);
+
+	/* from now on, pmap_bootstrap_alloc can't be used */
+	vm_page_startup_initialized = TRUE;
+}
+
+/*
+ *	vm_page_hash:
+ *
+ *	Distributes the object/offset key pair among hash buckets.
+ *
+ *	NOTE:  This macro depends on vm_page_bucket_count being a power of 2.
+ */
+#define vm_page_hash(object, offset) \
+	(((unsigned)object+(unsigned)atop(offset))&vm_page_hash_mask)
+
+/*
+ *	vm_page_insert:		[ internal use only ]
+ *
+ *	Inserts the given mem entry into the object/object-page
+ *	table and object list.
+ *
+ *	The object and page must be locked.
+ */
+
+void vm_page_insert(mem, object, offset)
+	register vm_page_t	mem;
+	register vm_object_t	object;
+	register vm_offset_t	offset;
+{
+	register struct pglist	*bucket;
+	int			spl;
+
+	VM_PAGE_CHECK(mem);
+
+	if (mem->flags & PG_TABLED)
+		panic("vm_page_insert: already inserted");
+
+	/*
+	 *	Record the object/offset pair in this page
+	 */
+
+	mem->object = object;
+	mem->offset = offset;
+
+	/*
+	 *	Insert it into the object_object/offset hash table
+	 */
+
+	bucket = &vm_page_buckets[vm_page_hash(object, offset)];
+	spl = splimp();
+	simple_lock(&bucket_lock);
+	TAILQ_INSERT_TAIL(bucket, mem, hashq);
+	simple_unlock(&bucket_lock);
+	(void) splx(spl);
+
+	/*
+	 *	Now link into the object's list of backed pages.
+	 */
+
+	TAILQ_INSERT_TAIL(&object->memq, mem, listq);
+	mem->flags |= PG_TABLED;
+
+	/*
+	 *	And show that the object has one more resident
+	 *	page.
+	 */
+
+	object->resident_page_count++;
+}
+
+/*
+ *	vm_page_remove:		[ internal use only ]
+ *				NOTE: used by device pager as well -wfj
+ *
+ *	Removes the given mem entry from the object/offset-page
+ *	table and the object page list.
+ *
+ *	The object and page must be locked.
+ */
+
+void vm_page_remove(mem)
+	register vm_page_t	mem;
+{
+	register struct pglist	*bucket;
+	int			spl;
+
+	VM_PAGE_CHECK(mem);
+
+	if (!(mem->flags & PG_TABLED))
+		return;
+
+	/*
+	 *	Remove from the object_object/offset hash table
+	 */
+
+	bucket = &vm_page_buckets[vm_page_hash(mem->object, mem->offset)];
+	spl = splimp();
+	simple_lock(&bucket_lock);
+	TAILQ_REMOVE(bucket, mem, hashq);
+	simple_unlock(&bucket_lock);
+	(void) splx(spl);
+
+	/*
+	 *	Now remove from the object's list of backed pages.
+	 */
+
+	TAILQ_REMOVE(&mem->object->memq, mem, listq);
+
+	/*
+	 *	And show that the object has one fewer resident
+	 *	page.
+	 */
+
+	mem->object->resident_page_count--;
+
+	mem->flags &= ~PG_TABLED;
+}
+
+/*
+ *	vm_page_lookup:
+ *
+ *	Returns the page associated with the object/offset
+ *	pair specified; if none is found, NULL is returned.
+ *
+ *	The object must be locked.  No side effects.
+ */
+
+vm_page_t vm_page_lookup(object, offset)
+	register vm_object_t	object;
+	register vm_offset_t	offset;
+{
+	register vm_page_t	mem;
+	register struct pglist	*bucket;
+	int			spl;
+
+	/*
+	 *	Search the hash table for this object/offset pair
+	 */
+
+	bucket = &vm_page_buckets[vm_page_hash(object, offset)];
+
+	spl = splimp();
+	simple_lock(&bucket_lock);
+	for (mem = bucket->tqh_first; mem != NULL; mem = mem->hashq.tqe_next) {
+		VM_PAGE_CHECK(mem);
+		if ((mem->object == object) && (mem->offset == offset)) {
+			simple_unlock(&bucket_lock);
+			splx(spl);
+			return(mem);
+		}
+	}
+
+	simple_unlock(&bucket_lock);
+	splx(spl);
+	return(NULL);
+}
+
+/*
+ *	vm_page_rename:
+ *
+ *	Move the given memory entry from its
+ *	current object to the specified target object/offset.
+ *
+ *	The object must be locked.
+ */
+void vm_page_rename(mem, new_object, new_offset)
+	register vm_page_t	mem;
+	register vm_object_t	new_object;
+	vm_offset_t		new_offset;
+{
+	if (mem->object == new_object)
+		return;
+
+	vm_page_lock_queues();	/* keep page from moving out from
+				   under pageout daemon */
+    	vm_page_remove(mem);
+	vm_page_insert(mem, new_object, new_offset);
+	vm_page_unlock_queues();
+}
+
+/*
+ *	vm_page_alloc:
+ *
+ *	Allocate and return a memory cell associated
+ *	with this VM object/offset pair.
+ *
+ *	Object must be locked.
+ */
+vm_page_t vm_page_alloc(object, offset)
+	vm_object_t	object;
+	vm_offset_t	offset;
+{
+	register vm_page_t	mem;
+	int		spl;
+
+	spl = splimp();				/* XXX */
+	simple_lock(&vm_page_queue_free_lock);
+	if (vm_page_queue_free.tqh_first == NULL) {
+		simple_unlock(&vm_page_queue_free_lock);
+		splx(spl);
+		return(NULL);
+	}
+
+	mem = vm_page_queue_free.tqh_first;
+	TAILQ_REMOVE(&vm_page_queue_free, mem, pageq);
+
+	cnt.v_free_count--;
+	simple_unlock(&vm_page_queue_free_lock);
+	splx(spl);
+
+	VM_PAGE_INIT(mem, object, offset);
+
+	/*
+	 *	Decide if we should poke the pageout daemon.
+	 *	We do this if the free count is less than the low
+	 *	water mark, or if the free count is less than the high
+	 *	water mark (but above the low water mark) and the inactive
+	 *	count is less than its target.
+	 *
+	 *	We don't have the counts locked ... if they change a little,
+	 *	it doesn't really matter.
+	 */
+
+	if (cnt.v_free_count < cnt.v_free_min ||
+	    (cnt.v_free_count < cnt.v_free_target &&
+	     cnt.v_inactive_count < cnt.v_inactive_target))
+		thread_wakeup((int)&vm_pages_needed);
+	return (mem);
+}
+
+/*
+ *	vm_page_free:
+ *
+ *	Returns the given page to the free list,
+ *	disassociating it with any VM object.
+ *
+ *	Object and page must be locked prior to entry.
+ */
+void vm_page_free(mem)
+	register vm_page_t	mem;
+{
+	vm_page_remove(mem);
+	if (mem->flags & PG_ACTIVE) {
+		TAILQ_REMOVE(&vm_page_queue_active, mem, pageq);
+		mem->flags &= ~PG_ACTIVE;
+		cnt.v_active_count--;
+	}
+
+	if (mem->flags & PG_INACTIVE) {
+		TAILQ_REMOVE(&vm_page_queue_inactive, mem, pageq);
+		mem->flags &= ~PG_INACTIVE;
+		cnt.v_inactive_count--;
+	}
+
+	if (!(mem->flags & PG_FICTITIOUS)) {
+		int	spl;
+
+		spl = splimp();
+		simple_lock(&vm_page_queue_free_lock);
+		TAILQ_INSERT_TAIL(&vm_page_queue_free, mem, pageq);
+
+		cnt.v_free_count++;
+		simple_unlock(&vm_page_queue_free_lock);
+		splx(spl);
+	}
+}
+
+/*
+ *	vm_page_wire:
+ *
+ *	Mark this page as wired down by yet
+ *	another map, removing it from paging queues
+ *	as necessary.
+ *
+ *	The page queues must be locked.
+ */
+void vm_page_wire(mem)
+	register vm_page_t	mem;
+{
+	VM_PAGE_CHECK(mem);
+
+	if (mem->wire_count == 0) {
+		if (mem->flags & PG_ACTIVE) {
+			TAILQ_REMOVE(&vm_page_queue_active, mem, pageq);
+			cnt.v_active_count--;
+			mem->flags &= ~PG_ACTIVE;
+		}
+		if (mem->flags & PG_INACTIVE) {
+			TAILQ_REMOVE(&vm_page_queue_inactive, mem, pageq);
+			cnt.v_inactive_count--;
+			mem->flags &= ~PG_INACTIVE;
+		}
+		cnt.v_wire_count++;
+	}
+	mem->wire_count++;
+}
+
+/*
+ *	vm_page_unwire:
+ *
+ *	Release one wiring of this page, potentially
+ *	enabling it to be paged again.
+ *
+ *	The page queues must be locked.
+ */
+void vm_page_unwire(mem)
+	register vm_page_t	mem;
+{
+	VM_PAGE_CHECK(mem);
+
+	mem->wire_count--;
+	if (mem->wire_count == 0) {
+		TAILQ_INSERT_TAIL(&vm_page_queue_active, mem, pageq);
+		cnt.v_active_count++;
+		mem->flags |= PG_ACTIVE;
+		cnt.v_wire_count--;
+	}
+}
+
+/*
+ *	vm_page_deactivate:
+ *
+ *	Returns the given page to the inactive list,
+ *	indicating that no physical maps have access
+ *	to this page.  [Used by the physical mapping system.]
+ *
+ *	The page queues must be locked.
+ */
+void vm_page_deactivate(m)
+	register vm_page_t	m;
+{
+	VM_PAGE_CHECK(m);
+
+	/*
+	 *	Only move active pages -- ignore locked or already
+	 *	inactive ones.
+	 */
+
+	if (m->flags & PG_ACTIVE) {
+		pmap_clear_reference(VM_PAGE_TO_PHYS(m));
+		TAILQ_REMOVE(&vm_page_queue_active, m, pageq);
+		TAILQ_INSERT_TAIL(&vm_page_queue_inactive, m, pageq);
+		m->flags &= ~PG_ACTIVE;
+		m->flags |= PG_INACTIVE;
+		cnt.v_active_count--;
+		cnt.v_inactive_count++;
+		if (pmap_is_modified(VM_PAGE_TO_PHYS(m)))
+			m->flags &= ~PG_CLEAN;
+		if (m->flags & PG_CLEAN)
+			m->flags &= ~PG_LAUNDRY;
+		else
+			m->flags |= PG_LAUNDRY;
+	}
+}
+
+/*
+ *	vm_page_activate:
+ *
+ *	Put the specified page on the active list (if appropriate).
+ *
+ *	The page queues must be locked.
+ */
+
+void vm_page_activate(m)
+	register vm_page_t	m;
+{
+	VM_PAGE_CHECK(m);
+
+	if (m->flags & PG_INACTIVE) {
+		TAILQ_REMOVE(&vm_page_queue_inactive, m, pageq);
+		cnt.v_inactive_count--;
+		m->flags &= ~PG_INACTIVE;
+	}
+	if (m->wire_count == 0) {
+		if (m->flags & PG_ACTIVE)
+			panic("vm_page_activate: already active");
+
+		TAILQ_INSERT_TAIL(&vm_page_queue_active, m, pageq);
+		m->flags |= PG_ACTIVE;
+		cnt.v_active_count++;
+	}
+}
+
+/*
+ *	vm_page_zero_fill:
+ *
+ *	Zero-fill the specified page.
+ *	Written as a standard pagein routine, to
+ *	be used by the zero-fill object.
+ */
+
+boolean_t vm_page_zero_fill(m)
+	vm_page_t	m;
+{
+	VM_PAGE_CHECK(m);
+
+	m->flags &= ~PG_CLEAN;
+	pmap_zero_page(VM_PAGE_TO_PHYS(m));
+	return(TRUE);
+}
+
+/*
+ *	vm_page_copy:
+ *
+ *	Copy one page to another
+ */
+
+void vm_page_copy(src_m, dest_m)
+	vm_page_t	src_m;
+	vm_page_t	dest_m;
+{
+	VM_PAGE_CHECK(src_m);
+	VM_PAGE_CHECK(dest_m);
+
+	dest_m->flags &= ~PG_CLEAN;
+	pmap_copy_page(VM_PAGE_TO_PHYS(src_m), VM_PAGE_TO_PHYS(dest_m));
+}
diff --git a/sys/vm/vm_page.h b/sys/vm/vm_page.h
new file mode 100644
index 0000000..8bf5146
--- /dev/null
+++ b/sys/vm/vm_page.h
@@ -0,0 +1,242 @@
+/* 
+ * Copyright (c) 1991, 1993
+ *	The Regents of the University of California.  All rights reserved.
+ *
+ * This code is derived from software contributed to Berkeley by
+ * The Mach Operating System project at Carnegie-Mellon University.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. All advertising materials mentioning features or use of this software
+ *    must display the following acknowledgement:
+ *	This product includes software developed by the University of
+ *	California, Berkeley and its contributors.
+ * 4. Neither the name of the University nor the names of its contributors
+ *    may be used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ *
+ *	@(#)vm_page.h	8.2 (Berkeley) 12/13/93
+ *
+ *
+ * Copyright (c) 1987, 1990 Carnegie-Mellon University.
+ * All rights reserved.
+ *
+ * Authors: Avadis Tevanian, Jr., Michael Wayne Young
+ * 
+ * Permission to use, copy, modify and distribute this software and
+ * its documentation is hereby granted, provided that both the copyright
+ * notice and this permission notice appear in all copies of the
+ * software, derivative works or modified versions, and any portions
+ * thereof, and that both notices appear in supporting documentation.
+ * 
+ * CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS" 
+ * CONDITION.  CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND 
+ * FOR ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
+ * 
+ * Carnegie Mellon requests users of this software to return to
+ *
+ *  Software Distribution Coordinator  or  Software.Distribution@CS.CMU.EDU
+ *  School of Computer Science
+ *  Carnegie Mellon University
+ *  Pittsburgh PA 15213-3890
+ *
+ * any improvements or extensions that they make and grant Carnegie the
+ * rights to redistribute these changes.
+ */
+
+/*
+ *	Resident memory system definitions.
+ */
+
+#ifndef	_VM_PAGE_
+#define	_VM_PAGE_
+
+/*
+ *	Management of resident (logical) pages.
+ *
+ *	A small structure is kept for each resident
+ *	page, indexed by page number.  Each structure
+ *	is an element of several lists:
+ *
+ *		A hash table bucket used to quickly
+ *		perform object/offset lookups
+ *
+ *		A list of all pages for a given object,
+ *		so they can be quickly deactivated at
+ *		time of deallocation.
+ *
+ *		An ordered list of pages due for pageout.
+ *
+ *	In addition, the structure contains the object
+ *	and offset to which this page belongs (for pageout),
+ *	and sundry status bits.
+ *
+ *	Fields in this structure are locked either by the lock on the
+ *	object that the page belongs to (O) or by the lock on the page
+ *	queues (P).
+ */
+
+TAILQ_HEAD(pglist, vm_page);
+
+struct vm_page {
+	TAILQ_ENTRY(vm_page)	pageq;		/* queue info for FIFO
+						 * queue or free list (P) */
+	TAILQ_ENTRY(vm_page)	hashq;		/* hash table links (O)*/
+	TAILQ_ENTRY(vm_page)	listq;		/* pages in same object (O)*/
+
+	vm_object_t		object;		/* which object am I in (O,P)*/
+	vm_offset_t		offset;		/* offset into object (O,P) */
+
+	u_short			wire_count;	/* wired down maps refs (P) */
+	u_short			flags;		/* see below */
+
+	vm_offset_t		phys_addr;	/* physical address of page */
+};
+
+/*
+ * These are the flags defined for vm_page.
+ *
+ * Note: PG_FILLED and PG_DIRTY are added for the filesystems.
+ */
+#define	PG_INACTIVE	0x0001		/* page is in inactive list (P) */
+#define	PG_ACTIVE	0x0002		/* page is in active list (P) */
+#define	PG_LAUNDRY	0x0004		/* page is being cleaned now (P)*/
+#define	PG_CLEAN	0x0008		/* page has not been modified */
+#define	PG_BUSY		0x0010		/* page is in transit (O) */
+#define	PG_WANTED	0x0020		/* someone is waiting for page (O) */
+#define	PG_TABLED	0x0040		/* page is in VP table (O) */
+#define	PG_COPYONWRITE	0x0080		/* must copy page before changing (O) */
+#define	PG_FICTITIOUS	0x0100		/* physical page doesn't exist (O) */
+#define	PG_FAKE		0x0200		/* page is placeholder for pagein (O) */
+#define	PG_FILLED	0x0400		/* client flag to set when filled */
+#define	PG_DIRTY	0x0800		/* client flag to set when dirty */
+#define	PG_PAGEROWNED	0x4000		/* DEBUG: async paging op in progress */
+#define	PG_PTPAGE	0x8000		/* DEBUG: is a user page table page */
+
+#if	VM_PAGE_DEBUG
+#define	VM_PAGE_CHECK(mem) { \
+	if ((((unsigned int) mem) < ((unsigned int) &vm_page_array[0])) || \
+	    (((unsigned int) mem) > \
+		((unsigned int) &vm_page_array[last_page-first_page])) || \
+	    ((mem->flags & (PG_ACTIVE | PG_INACTIVE)) == \
+		(PG_ACTIVE | PG_INACTIVE))) \
+		panic("vm_page_check: not valid!"); \
+}
+#else /* VM_PAGE_DEBUG */
+#define	VM_PAGE_CHECK(mem)
+#endif /* VM_PAGE_DEBUG */
+
+#ifdef KERNEL
+/*
+ *	Each pageable resident page falls into one of three lists:
+ *
+ *	free	
+ *		Available for allocation now.
+ *	inactive
+ *		Not referenced in any map, but still has an
+ *		object/offset-page mapping, and may be dirty.
+ *		This is the list of pages that should be
+ *		paged out next.
+ *	active
+ *		A list of pages which have been placed in
+ *		at least one physical map.  This list is
+ *		ordered, in LRU-like fashion.
+ */
+
+extern
+struct pglist	vm_page_queue_free;	/* memory free queue */
+extern
+struct pglist	vm_page_queue_active;	/* active memory queue */
+extern
+struct pglist	vm_page_queue_inactive;	/* inactive memory queue */
+
+extern
+vm_page_t	vm_page_array;		/* First resident page in table */
+extern
+long		first_page;		/* first physical page number */
+					/* ... represented in vm_page_array */
+extern
+long		last_page;		/* last physical page number */
+					/* ... represented in vm_page_array */
+					/* [INCLUSIVE] */
+extern
+vm_offset_t	first_phys_addr;	/* physical address for first_page */
+extern
+vm_offset_t	last_phys_addr;		/* physical address for last_page */
+
+#define VM_PAGE_TO_PHYS(entry)	((entry)->phys_addr)
+
+#define IS_VM_PHYSADDR(pa) \
+		((pa) >= first_phys_addr && (pa) <= last_phys_addr)
+
+#define PHYS_TO_VM_PAGE(pa) \
+		(&vm_page_array[atop(pa) - first_page ])
+
+extern
+simple_lock_data_t	vm_page_queue_lock;	/* lock on active and inactive
+						   page queues */
+extern						/* lock on free page queue */
+simple_lock_data_t	vm_page_queue_free_lock;
+
+/*
+ *	Functions implemented as macros
+ */
+
+#define PAGE_ASSERT_WAIT(m, interruptible)	{ \
+				(m)->flags |= PG_WANTED; \
+				assert_wait((int) (m), (interruptible)); \
+			}
+
+#define PAGE_WAKEUP(m)	{ \
+				(m)->flags &= ~PG_BUSY; \
+				if ((m)->flags & PG_WANTED) { \
+					(m)->flags &= ~PG_WANTED; \
+					thread_wakeup((int) (m)); \
+				} \
+			}
+
+#define	vm_page_lock_queues()	simple_lock(&vm_page_queue_lock)
+#define	vm_page_unlock_queues()	simple_unlock(&vm_page_queue_lock)
+
+#define vm_page_set_modified(m)	{ (m)->flags &= ~PG_CLEAN; }
+
+#define	VM_PAGE_INIT(mem, object, offset) { \
+	(mem)->flags = PG_BUSY | PG_CLEAN | PG_FAKE; \
+	vm_page_insert((mem), (object), (offset)); \
+	(mem)->wire_count = 0; \
+}
+
+void		 vm_page_activate __P((vm_page_t));
+vm_page_t	 vm_page_alloc __P((vm_object_t, vm_offset_t));
+void		 vm_page_copy __P((vm_page_t, vm_page_t));
+void		 vm_page_deactivate __P((vm_page_t));
+void		 vm_page_free __P((vm_page_t));
+void		 vm_page_insert __P((vm_page_t, vm_object_t, vm_offset_t));
+vm_page_t	 vm_page_lookup __P((vm_object_t, vm_offset_t));
+void		 vm_page_remove __P((vm_page_t));
+void		 vm_page_rename __P((vm_page_t, vm_object_t, vm_offset_t));
+void		 vm_page_startup __P((vm_offset_t *, vm_offset_t *));
+void		 vm_page_unwire __P((vm_page_t));
+void		 vm_page_wire __P((vm_page_t));
+boolean_t	 vm_page_zero_fill __P((vm_page_t));
+
+#endif /* KERNEL */
+#endif /* !_VM_PAGE_ */
diff --git a/sys/vm/vm_pageout.c b/sys/vm/vm_pageout.c
new file mode 100644
index 0000000..6795405
--- /dev/null
+++ b/sys/vm/vm_pageout.c
@@ -0,0 +1,567 @@
+/* 
+ * Copyright (c) 1991, 1993
+ *	The Regents of the University of California.  All rights reserved.
+ *
+ * This code is derived from software contributed to Berkeley by
+ * The Mach Operating System project at Carnegie-Mellon University.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. All advertising materials mentioning features or use of this software
+ *    must display the following acknowledgement:
+ *	This product includes software developed by the University of
+ *	California, Berkeley and its contributors.
+ * 4. Neither the name of the University nor the names of its contributors
+ *    may be used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ *
+ *	@(#)vm_pageout.c	8.5 (Berkeley) 2/14/94
+ *
+ *
+ * Copyright (c) 1987, 1990 Carnegie-Mellon University.
+ * All rights reserved.
+ *
+ * Authors: Avadis Tevanian, Jr., Michael Wayne Young
+ * 
+ * Permission to use, copy, modify and distribute this software and
+ * its documentation is hereby granted, provided that both the copyright
+ * notice and this permission notice appear in all copies of the
+ * software, derivative works or modified versions, and any portions
+ * thereof, and that both notices appear in supporting documentation.
+ * 
+ * CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS" 
+ * CONDITION.  CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND 
+ * FOR ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
+ * 
+ * Carnegie Mellon requests users of this software to return to
+ *
+ *  Software Distribution Coordinator  or  Software.Distribution@CS.CMU.EDU
+ *  School of Computer Science
+ *  Carnegie Mellon University
+ *  Pittsburgh PA 15213-3890
+ *
+ * any improvements or extensions that they make and grant Carnegie the
+ * rights to redistribute these changes.
+ */
+
+/*
+ *	The proverbial page-out daemon.
+ */
+
+#include <sys/param.h>
+
+#include <vm/vm.h>
+#include <vm/vm_page.h>
+#include <vm/vm_pageout.h>
+
+#ifndef VM_PAGE_FREE_MIN
+#define VM_PAGE_FREE_MIN	(cnt.v_free_count / 20)
+#endif
+
+#ifndef VM_PAGE_FREE_TARGET
+#define VM_PAGE_FREE_TARGET	((cnt.v_free_min * 4) / 3)
+#endif
+
+int	vm_page_free_min_min = 16 * 1024;
+int	vm_page_free_min_max = 256 * 1024;
+
+int	vm_pages_needed;	/* Event on which pageout daemon sleeps */
+
+int	vm_page_max_wired = 0;	/* XXX max # of wired pages system-wide */
+
+#ifdef CLUSTERED_PAGEOUT
+#define MAXPOCLUSTER		(MAXPHYS/NBPG)	/* XXX */
+int doclustered_pageout = 1;
+#endif
+
+/*
+ *	vm_pageout_scan does the dirty work for the pageout daemon.
+ */
+void
+vm_pageout_scan()
+{
+	register vm_page_t	m, next;
+	register int		page_shortage;
+	register int		s;
+	register int		pages_freed;
+	int			free;
+	vm_object_t		object;
+
+	/*
+	 *	Only continue when we want more pages to be "free"
+	 */
+
+	cnt.v_rev++;
+
+	s = splimp();
+	simple_lock(&vm_page_queue_free_lock);
+	free = cnt.v_free_count;
+	simple_unlock(&vm_page_queue_free_lock);
+	splx(s);
+
+	if (free < cnt.v_free_target) {
+		swapout_threads();
+
+		/*
+		 *	Be sure the pmap system is updated so
+		 *	we can scan the inactive queue.
+		 */
+
+		pmap_update();
+	}
+
+	/*
+	 *	Acquire the resident page system lock,
+	 *	as we may be changing what's resident quite a bit.
+	 */
+	vm_page_lock_queues();
+
+	/*
+	 *	Start scanning the inactive queue for pages we can free.
+	 *	We keep scanning until we have enough free pages or
+	 *	we have scanned through the entire queue.  If we
+	 *	encounter dirty pages, we start cleaning them.
+	 */
+
+	pages_freed = 0;
+	for (m = vm_page_queue_inactive.tqh_first; m != NULL; m = next) {
+		s = splimp();
+		simple_lock(&vm_page_queue_free_lock);
+		free = cnt.v_free_count;
+		simple_unlock(&vm_page_queue_free_lock);
+		splx(s);
+		if (free >= cnt.v_free_target)
+			break;
+
+		cnt.v_scan++;
+		next = m->pageq.tqe_next;
+
+		/*
+		 * If the page has been referenced, move it back to the
+		 * active queue.
+		 */
+		if (pmap_is_referenced(VM_PAGE_TO_PHYS(m))) {
+			vm_page_activate(m);
+			cnt.v_reactivated++;
+			continue;
+		}
+
+		/*
+		 * If the page is clean, free it up.
+		 */
+		if (m->flags & PG_CLEAN) {
+			object = m->object;
+			if (vm_object_lock_try(object)) {
+				pmap_page_protect(VM_PAGE_TO_PHYS(m),
+						  VM_PROT_NONE);
+				vm_page_free(m);
+				pages_freed++;
+				cnt.v_dfree++;
+				vm_object_unlock(object);
+			}
+			continue;
+		}
+
+		/*
+		 * If the page is dirty but already being washed, skip it.
+		 */
+		if ((m->flags & PG_LAUNDRY) == 0)
+			continue;
+
+		/*
+		 * Otherwise the page is dirty and still in the laundry,
+		 * so we start the cleaning operation and remove it from
+		 * the laundry.
+		 */
+		object = m->object;
+		if (!vm_object_lock_try(object))
+			continue;
+		cnt.v_pageouts++;
+#ifdef CLUSTERED_PAGEOUT
+		if (object->pager &&
+		    vm_pager_cancluster(object->pager, PG_CLUSTERPUT))
+			vm_pageout_cluster(m, object);
+		else
+#endif
+		vm_pageout_page(m, object);
+		thread_wakeup((int) object);
+		vm_object_unlock(object);
+		/*
+		 * Former next page may no longer even be on the inactive
+		 * queue (due to potential blocking in the pager with the
+		 * queues unlocked).  If it isn't, we just start over.
+		 */
+		if (next && (next->flags & PG_INACTIVE) == 0)
+			next = vm_page_queue_inactive.tqh_first;
+	}
+	
+	/*
+	 *	Compute the page shortage.  If we are still very low on memory
+	 *	be sure that we will move a minimal amount of pages from active
+	 *	to inactive.
+	 */
+
+	page_shortage = cnt.v_inactive_target - cnt.v_inactive_count;
+	if (page_shortage <= 0 && pages_freed == 0)
+		page_shortage = 1;
+
+	while (page_shortage > 0) {
+		/*
+		 *	Move some more pages from active to inactive.
+		 */
+
+		if ((m = vm_page_queue_active.tqh_first) == NULL)
+			break;
+		vm_page_deactivate(m);
+		page_shortage--;
+	}
+
+	vm_page_unlock_queues();
+}
+
+/*
+ * Called with object and page queues locked.
+ * If reactivate is TRUE, a pager error causes the page to be
+ * put back on the active queue, ow it is left on the inactive queue.
+ */
+void
+vm_pageout_page(m, object)
+	vm_page_t m;
+	vm_object_t object;
+{
+	vm_pager_t pager;
+	int pageout_status;
+
+	/*
+	 * We set the busy bit to cause potential page faults on
+	 * this page to block.
+	 *
+	 * We also set pageout-in-progress to keep the object from
+	 * disappearing during pageout.  This guarantees that the
+	 * page won't move from the inactive queue.  (However, any
+	 * other page on the inactive queue may move!)
+	 */
+	pmap_page_protect(VM_PAGE_TO_PHYS(m), VM_PROT_NONE);
+	m->flags |= PG_BUSY;
+
+	/*
+	 * Try to collapse the object before making a pager for it.
+	 * We must unlock the page queues first.
+	 */
+	vm_page_unlock_queues();
+	if (object->pager == NULL)
+		vm_object_collapse(object);
+
+	object->paging_in_progress++;
+	vm_object_unlock(object);
+
+	/*
+	 * Do a wakeup here in case the following operations block.
+	 */
+	thread_wakeup((int) &cnt.v_free_count);
+
+	/*
+	 * If there is no pager for the page, use the default pager.
+	 * If there is no place to put the page at the moment,
+	 * leave it in the laundry and hope that there will be
+	 * paging space later.
+	 */
+	if ((pager = object->pager) == NULL) {
+		pager = vm_pager_allocate(PG_DFLT, (caddr_t)0, object->size,
+					  VM_PROT_ALL, (vm_offset_t)0);
+		if (pager != NULL)
+			vm_object_setpager(object, pager, 0, FALSE);
+	}
+	pageout_status = pager ? vm_pager_put(pager, m, FALSE) : VM_PAGER_FAIL;
+	vm_object_lock(object);
+	vm_page_lock_queues();
+
+	switch (pageout_status) {
+	case VM_PAGER_OK:
+	case VM_PAGER_PEND:
+		cnt.v_pgpgout++;
+		m->flags &= ~PG_LAUNDRY;
+		break;
+	case VM_PAGER_BAD:
+		/*
+		 * Page outside of range of object.  Right now we
+		 * essentially lose the changes by pretending it
+		 * worked.
+		 *
+		 * XXX dubious, what should we do?
+		 */
+		m->flags &= ~PG_LAUNDRY;
+		m->flags |= PG_CLEAN;
+		pmap_clear_modify(VM_PAGE_TO_PHYS(m));
+		break;
+	case VM_PAGER_AGAIN:
+	{
+		extern int lbolt;
+
+		/*
+		 * FAIL on a write is interpreted to mean a resource
+		 * shortage, so we put pause for awhile and try again.
+		 * XXX could get stuck here.
+		 */
+		(void) tsleep((caddr_t)&lbolt, PZERO|PCATCH, "pageout", 0);
+		break;
+	}
+	case VM_PAGER_FAIL:
+	case VM_PAGER_ERROR:
+		/*
+		 * If page couldn't be paged out, then reactivate
+		 * the page so it doesn't clog the inactive list.
+		 * (We will try paging out it again later).
+		 */
+		vm_page_activate(m);
+		cnt.v_reactivated++;
+		break;
+	}
+
+	pmap_clear_reference(VM_PAGE_TO_PHYS(m));
+
+	/*
+	 * If the operation is still going, leave the page busy
+	 * to block all other accesses.  Also, leave the paging
+	 * in progress indicator set so that we don't attempt an
+	 * object collapse.
+	 */
+	if (pageout_status != VM_PAGER_PEND) {
+		m->flags &= ~PG_BUSY;
+		PAGE_WAKEUP(m);
+		object->paging_in_progress--;
+	}
+}
+
+#ifdef CLUSTERED_PAGEOUT
+#define PAGEOUTABLE(p) \
+	((((p)->flags & (PG_INACTIVE|PG_CLEAN|PG_LAUNDRY)) == \
+	  (PG_INACTIVE|PG_LAUNDRY)) && !pmap_is_referenced(VM_PAGE_TO_PHYS(p)))
+
+/*
+ * Attempt to pageout as many contiguous (to ``m'') dirty pages as possible
+ * from ``object''.  Using information returned from the pager, we assemble
+ * a sorted list of contiguous dirty pages and feed them to the pager in one
+ * chunk.  Called with paging queues and object locked.  Also, object must
+ * already have a pager.
+ */
+void
+vm_pageout_cluster(m, object)
+	vm_page_t m;
+	vm_object_t object;
+{
+	vm_offset_t offset, loff, hoff;
+	vm_page_t plist[MAXPOCLUSTER], *plistp, p;
+	int postatus, ix, count;
+
+	/*
+	 * Determine the range of pages that can be part of a cluster
+	 * for this object/offset.  If it is only our single page, just
+	 * do it normally.
+	 */
+	vm_pager_cluster(object->pager, m->offset, &loff, &hoff);
+	if (hoff - loff == PAGE_SIZE) {
+		vm_pageout_page(m, object);
+		return;
+	}
+
+	plistp = plist;
+
+	/*
+	 * Target page is always part of the cluster.
+	 */
+	pmap_page_protect(VM_PAGE_TO_PHYS(m), VM_PROT_NONE);
+	m->flags |= PG_BUSY;
+	plistp[atop(m->offset - loff)] = m;
+	count = 1;
+
+	/*
+	 * Backup from the given page til we find one not fulfilling
+	 * the pageout criteria or we hit the lower bound for the
+	 * cluster.  For each page determined to be part of the
+	 * cluster, unmap it and busy it out so it won't change.
+	 */
+	ix = atop(m->offset - loff);
+	offset = m->offset;
+	while (offset > loff && count < MAXPOCLUSTER-1) {
+		p = vm_page_lookup(object, offset - PAGE_SIZE);
+		if (p == NULL || !PAGEOUTABLE(p))
+			break;
+		pmap_page_protect(VM_PAGE_TO_PHYS(p), VM_PROT_NONE);
+		p->flags |= PG_BUSY;
+		plistp[--ix] = p;
+		offset -= PAGE_SIZE;
+		count++;
+	}
+	plistp += atop(offset - loff);
+	loff = offset;
+
+	/*
+	 * Now do the same moving forward from the target.
+	 */
+	ix = atop(m->offset - loff) + 1;
+	offset = m->offset + PAGE_SIZE;
+	while (offset < hoff && count < MAXPOCLUSTER) {
+		p = vm_page_lookup(object, offset);
+		if (p == NULL || !PAGEOUTABLE(p))
+			break;
+		pmap_page_protect(VM_PAGE_TO_PHYS(p), VM_PROT_NONE);
+		p->flags |= PG_BUSY;
+		plistp[ix++] = p;
+		offset += PAGE_SIZE;
+		count++;
+	}
+	hoff = offset;
+
+	/*
+	 * Pageout the page.
+	 * Unlock everything and do a wakeup prior to the pager call
+	 * in case it blocks.
+	 */
+	vm_page_unlock_queues();
+	object->paging_in_progress++;
+	vm_object_unlock(object);
+again:
+	thread_wakeup((int) &cnt.v_free_count);
+	postatus = vm_pager_put_pages(object->pager, plistp, count, FALSE);
+	/*
+	 * XXX rethink this
+	 */
+	if (postatus == VM_PAGER_AGAIN) {
+		extern int lbolt;
+
+		(void) tsleep((caddr_t)&lbolt, PZERO|PCATCH, "pageout", 0);
+		goto again;
+	} else if (postatus == VM_PAGER_BAD)
+		panic("vm_pageout_cluster: VM_PAGER_BAD");
+	vm_object_lock(object);
+	vm_page_lock_queues();
+
+	/*
+	 * Loop through the affected pages, reflecting the outcome of
+	 * the operation.
+	 */
+	for (ix = 0; ix < count; ix++) {
+		p = *plistp++;
+		switch (postatus) {
+		case VM_PAGER_OK:
+		case VM_PAGER_PEND:
+			cnt.v_pgpgout++;
+			p->flags &= ~PG_LAUNDRY;
+			break;
+		case VM_PAGER_FAIL:
+		case VM_PAGER_ERROR:
+			/*
+			 * Pageout failed, reactivate the target page so it
+			 * doesn't clog the inactive list.  Other pages are
+			 * left as they are.
+			 */
+			if (p == m) {
+				vm_page_activate(p);
+				cnt.v_reactivated++;
+			}
+			break;
+		}
+		pmap_clear_reference(VM_PAGE_TO_PHYS(p));
+		/*
+		 * If the operation is still going, leave the page busy
+		 * to block all other accesses.
+		 */
+		if (postatus != VM_PAGER_PEND) {
+			p->flags &= ~PG_BUSY;
+			PAGE_WAKEUP(p);
+
+		}
+	}
+	/*
+	 * If the operation is still going, leave the paging in progress
+	 * indicator set so that we don't attempt an object collapse.
+	 */
+	if (postatus != VM_PAGER_PEND)
+		object->paging_in_progress--;
+
+}
+#endif
+
+/*
+ *	vm_pageout is the high level pageout daemon.
+ */
+
+void vm_pageout()
+{
+	(void) spl0();
+
+	/*
+	 *	Initialize some paging parameters.
+	 */
+
+	if (cnt.v_free_min == 0) {
+		cnt.v_free_min = VM_PAGE_FREE_MIN;
+		vm_page_free_min_min /= cnt.v_page_size;
+		vm_page_free_min_max /= cnt.v_page_size;
+		if (cnt.v_free_min < vm_page_free_min_min)
+			cnt.v_free_min = vm_page_free_min_min;
+		if (cnt.v_free_min > vm_page_free_min_max)
+			cnt.v_free_min = vm_page_free_min_max;
+	}
+
+	if (cnt.v_free_target == 0)
+		cnt.v_free_target = VM_PAGE_FREE_TARGET;
+
+	if (cnt.v_free_target <= cnt.v_free_min)
+		cnt.v_free_target = cnt.v_free_min + 1;
+
+	/* XXX does not really belong here */
+	if (vm_page_max_wired == 0)
+		vm_page_max_wired = cnt.v_free_count / 3;
+
+	/*
+	 *	The pageout daemon is never done, so loop
+	 *	forever.
+	 */
+
+	simple_lock(&vm_pages_needed_lock);
+	while (TRUE) {
+		thread_sleep((int) &vm_pages_needed, &vm_pages_needed_lock,
+			     FALSE);
+		/*
+		 * Compute the inactive target for this scan.
+		 * We need to keep a reasonable amount of memory in the
+		 * inactive list to better simulate LRU behavior.
+		 */
+		cnt.v_inactive_target =
+			(cnt.v_active_count + cnt.v_inactive_count) / 3;
+		if (cnt.v_inactive_target <= cnt.v_free_target)
+			cnt.v_inactive_target = cnt.v_free_target + 1;
+
+		/*
+		 * Only make a scan if we are likely to do something.
+		 * Otherwise we might have been awakened by a pager
+		 * to clean up async pageouts.
+		 */
+		if (cnt.v_free_count < cnt.v_free_target ||
+		    cnt.v_inactive_count < cnt.v_inactive_target)
+			vm_pageout_scan();
+		vm_pager_sync();
+		simple_lock(&vm_pages_needed_lock);
+		thread_wakeup((int) &cnt.v_free_count);
+	}
+}
diff --git a/sys/vm/vm_pageout.h b/sys/vm/vm_pageout.h
new file mode 100644
index 0000000..a82a0ea
--- /dev/null
+++ b/sys/vm/vm_pageout.h
@@ -0,0 +1,96 @@
+/* 
+ * Copyright (c) 1991, 1993
+ *	The Regents of the University of California.  All rights reserved.
+ *
+ * This code is derived from software contributed to Berkeley by
+ * The Mach Operating System project at Carnegie-Mellon University.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. All advertising materials mentioning features or use of this software
+ *    must display the following acknowledgement:
+ *	This product includes software developed by the University of
+ *	California, Berkeley and its contributors.
+ * 4. Neither the name of the University nor the names of its contributors
+ *    may be used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ *
+ *	@(#)vm_pageout.h	8.2 (Berkeley) 1/12/94
+ *
+ *
+ * Copyright (c) 1987, 1990 Carnegie-Mellon University.
+ * All rights reserved.
+ *
+ * Author: Avadis Tevanian, Jr.
+ * 
+ * Permission to use, copy, modify and distribute this software and
+ * its documentation is hereby granted, provided that both the copyright
+ * notice and this permission notice appear in all copies of the
+ * software, derivative works or modified versions, and any portions
+ * thereof, and that both notices appear in supporting documentation.
+ * 
+ * CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS" 
+ * CONDITION.  CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND 
+ * FOR ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
+ * 
+ * Carnegie Mellon requests users of this software to return to
+ *
+ *  Software Distribution Coordinator  or  Software.Distribution@CS.CMU.EDU
+ *  School of Computer Science
+ *  Carnegie Mellon University
+ *  Pittsburgh PA 15213-3890
+ *
+ * any improvements or extensions that they make and grant Carnegie the
+ * rights to redistribute these changes.
+ */
+
+/*
+ *	Header file for pageout daemon.
+ */
+
+/*
+ *	Exported data structures.
+ */
+
+extern int	vm_pages_needed;	/* should be some "event" structure */
+simple_lock_data_t	vm_pages_needed_lock;
+
+
+/*
+ *	Exported routines.
+ */
+
+/*
+ *	Signal pageout-daemon and wait for it.
+ */
+
+#define	VM_WAIT		{ \
+			simple_lock(&vm_pages_needed_lock); \
+			thread_wakeup((int)&vm_pages_needed); \
+			thread_sleep((int)&cnt.v_free_count, \
+				&vm_pages_needed_lock, FALSE); \
+			}
+#ifdef KERNEL
+void		 vm_pageout __P((void));
+void		 vm_pageout_scan __P((void));
+void		 vm_pageout_page __P((vm_page_t, vm_object_t));
+void		 vm_pageout_cluster __P((vm_page_t, vm_object_t));
+#endif
diff --git a/sys/vm/vm_pager.c b/sys/vm/vm_pager.c
new file mode 100644
index 0000000..7123abb
--- /dev/null
+++ b/sys/vm/vm_pager.c
@@ -0,0 +1,381 @@
+/* 
+ * Copyright (c) 1991, 1993
+ *	The Regents of the University of California.  All rights reserved.
+ *
+ * This code is derived from software contributed to Berkeley by
+ * The Mach Operating System project at Carnegie-Mellon University.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. All advertising materials mentioning features or use of this software
+ *    must display the following acknowledgement:
+ *	This product includes software developed by the University of
+ *	California, Berkeley and its contributors.
+ * 4. Neither the name of the University nor the names of its contributors
+ *    may be used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ *
+ *	@(#)vm_pager.c	8.6 (Berkeley) 1/12/94
+ *
+ *
+ * Copyright (c) 1987, 1990 Carnegie-Mellon University.
+ * All rights reserved.
+ *
+ * Authors: Avadis Tevanian, Jr., Michael Wayne Young
+ * 
+ * Permission to use, copy, modify and distribute this software and
+ * its documentation is hereby granted, provided that both the copyright
+ * notice and this permission notice appear in all copies of the
+ * software, derivative works or modified versions, and any portions
+ * thereof, and that both notices appear in supporting documentation.
+ * 
+ * CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS" 
+ * CONDITION.  CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND 
+ * FOR ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
+ * 
+ * Carnegie Mellon requests users of this software to return to
+ *
+ *  Software Distribution Coordinator  or  Software.Distribution@CS.CMU.EDU
+ *  School of Computer Science
+ *  Carnegie Mellon University
+ *  Pittsburgh PA 15213-3890
+ *
+ * any improvements or extensions that they make and grant Carnegie the
+ * rights to redistribute these changes.
+ */
+
+/*
+ *	Paging space routine stubs.  Emulates a matchmaker-like interface
+ *	for builtin pagers.
+ */
+
+#include <sys/param.h>
+#include <sys/systm.h>
+#include <sys/malloc.h>
+
+#include <vm/vm.h>
+#include <vm/vm_page.h>
+#include <vm/vm_kern.h>
+
+#ifdef SWAPPAGER
+extern struct pagerops swappagerops;
+#endif
+
+#ifdef VNODEPAGER
+extern struct pagerops vnodepagerops;
+#endif
+
+#ifdef DEVPAGER
+extern struct pagerops devicepagerops;
+#endif
+
+struct pagerops *pagertab[] = {
+#ifdef SWAPPAGER
+	&swappagerops,		/* PG_SWAP */
+#else
+	NULL,
+#endif
+#ifdef VNODEPAGER
+	&vnodepagerops,		/* PG_VNODE */
+#else
+	NULL,
+#endif
+#ifdef DEVPAGER
+	&devicepagerops,	/* PG_DEV */
+#else
+	NULL,
+#endif
+};
+int npagers = sizeof (pagertab) / sizeof (pagertab[0]);
+
+struct pagerops *dfltpagerops = NULL;	/* default pager */
+
+/*
+ * Kernel address space for mapping pages.
+ * Used by pagers where KVAs are needed for IO.
+ *
+ * XXX needs to be large enough to support the number of pending async
+ * cleaning requests (NPENDINGIO == 64) * the maximum swap cluster size
+ * (MAXPHYS == 64k) if you want to get the most efficiency.
+ */
+#define PAGER_MAP_SIZE	(4 * 1024 * 1024)
+
+vm_map_t pager_map;
+boolean_t pager_map_wanted;
+vm_offset_t pager_sva, pager_eva;
+
+void
+vm_pager_init()
+{
+	struct pagerops **pgops;
+
+	/*
+	 * Allocate a kernel submap for tracking get/put page mappings
+	 */
+	pager_map = kmem_suballoc(kernel_map, &pager_sva, &pager_eva,
+				  PAGER_MAP_SIZE, FALSE);
+	/*
+	 * Initialize known pagers
+	 */
+	for (pgops = pagertab; pgops < &pagertab[npagers]; pgops++)
+		if (pgops)
+			(*(*pgops)->pgo_init)();
+	if (dfltpagerops == NULL)
+		panic("no default pager");
+}
+
+/*
+ * Allocate an instance of a pager of the given type.
+ * Size, protection and offset parameters are passed in for pagers that
+ * need to perform page-level validation (e.g. the device pager).
+ */
+vm_pager_t
+vm_pager_allocate(type, handle, size, prot, off)
+	int type;
+	caddr_t handle;
+	vm_size_t size;
+	vm_prot_t prot;
+	vm_offset_t off;
+{
+	struct pagerops *ops;
+
+	ops = (type == PG_DFLT) ? dfltpagerops : pagertab[type];
+	if (ops)
+		return ((*ops->pgo_alloc)(handle, size, prot, off));
+	return (NULL);
+}
+
+void
+vm_pager_deallocate(pager)
+	vm_pager_t	pager;
+{
+	if (pager == NULL)
+		panic("vm_pager_deallocate: null pager");
+
+	(*pager->pg_ops->pgo_dealloc)(pager);
+}
+
+int
+vm_pager_get_pages(pager, mlist, npages, sync)
+	vm_pager_t	pager;
+	vm_page_t	*mlist;
+	int		npages;
+	boolean_t	sync;
+{
+	int rv;
+
+	if (pager == NULL) {
+		rv = VM_PAGER_OK;
+		while (npages--)
+			if (!vm_page_zero_fill(*mlist)) {
+				rv = VM_PAGER_FAIL;
+				break;
+			} else
+				mlist++;
+		return (rv);
+	}
+	return ((*pager->pg_ops->pgo_getpages)(pager, mlist, npages, sync));
+}
+
+int
+vm_pager_put_pages(pager, mlist, npages, sync)
+	vm_pager_t	pager;
+	vm_page_t	*mlist;
+	int		npages;
+	boolean_t	sync;
+{
+	if (pager == NULL)
+		panic("vm_pager_put_pages: null pager");
+	return ((*pager->pg_ops->pgo_putpages)(pager, mlist, npages, sync));
+}
+
+boolean_t
+vm_pager_has_page(pager, offset)
+	vm_pager_t	pager;
+	vm_offset_t	offset;
+{
+	if (pager == NULL)
+		panic("vm_pager_has_page: null pager");
+	return ((*pager->pg_ops->pgo_haspage)(pager, offset));
+}
+
+/*
+ * Called by pageout daemon before going back to sleep.
+ * Gives pagers a chance to clean up any completed async pageing operations.
+ */
+void
+vm_pager_sync()
+{
+	struct pagerops **pgops;
+
+	for (pgops = pagertab; pgops < &pagertab[npagers]; pgops++)
+		if (pgops)
+			(*(*pgops)->pgo_putpages)(NULL, NULL, 0, FALSE);
+}
+
+void
+vm_pager_cluster(pager, offset, loff, hoff)
+	vm_pager_t	pager;
+	vm_offset_t	offset;
+	vm_offset_t	*loff;
+	vm_offset_t	*hoff;
+{
+	if (pager == NULL)
+		panic("vm_pager_cluster: null pager");
+	return ((*pager->pg_ops->pgo_cluster)(pager, offset, loff, hoff));
+}
+
+void
+vm_pager_clusternull(pager, offset, loff, hoff)
+	vm_pager_t	pager;
+	vm_offset_t	offset;
+	vm_offset_t	*loff;
+	vm_offset_t	*hoff;
+{
+	panic("vm_pager_nullcluster called");
+}
+
+vm_offset_t
+vm_pager_map_pages(mlist, npages, canwait)
+	vm_page_t	*mlist;
+	int		npages;
+	boolean_t	canwait;
+{
+	vm_offset_t kva, va;
+	vm_size_t size;
+	vm_page_t m;
+
+	/*
+	 * Allocate space in the pager map, if none available return 0.
+	 * This is basically an expansion of kmem_alloc_wait with optional
+	 * blocking on no space.
+	 */
+	size = npages * PAGE_SIZE;
+	vm_map_lock(pager_map);
+	while (vm_map_findspace(pager_map, 0, size, &kva)) {
+		if (!canwait) {
+			vm_map_unlock(pager_map);
+			return (0);
+		}
+		pager_map_wanted = TRUE;
+		vm_map_unlock(pager_map);
+		(void) tsleep(pager_map, PVM, "pager_map", 0);
+		vm_map_lock(pager_map);
+	}
+	vm_map_insert(pager_map, NULL, 0, kva, kva + size);
+	vm_map_unlock(pager_map);
+
+	for (va = kva; npages--; va += PAGE_SIZE) {
+		m = *mlist++;
+#ifdef DEBUG
+		if ((m->flags & PG_BUSY) == 0)
+			panic("vm_pager_map_pages: page not busy");
+		if (m->flags & PG_PAGEROWNED)
+			panic("vm_pager_map_pages: page already in pager");
+#endif
+#ifdef DEBUG
+		m->flags |= PG_PAGEROWNED;
+#endif
+		pmap_enter(vm_map_pmap(pager_map), va, VM_PAGE_TO_PHYS(m),
+			   VM_PROT_DEFAULT, TRUE);
+	}
+	return (kva);
+}
+
+void
+vm_pager_unmap_pages(kva, npages)
+	vm_offset_t	kva;
+	int		npages;
+{
+	vm_size_t size = npages * PAGE_SIZE;
+
+#ifdef DEBUG
+	vm_offset_t va;
+	vm_page_t m;
+	int np = npages;
+
+	for (va = kva; np--; va += PAGE_SIZE) {
+		m = vm_pager_atop(va);
+		if (m->flags & PG_PAGEROWNED)
+			m->flags &= ~PG_PAGEROWNED;
+		else
+			printf("vm_pager_unmap_pages: %x(%x/%x) not owned\n",
+			       m, va, VM_PAGE_TO_PHYS(m));
+	}
+#endif
+	pmap_remove(vm_map_pmap(pager_map), kva, kva + size);
+	vm_map_lock(pager_map);
+	(void) vm_map_delete(pager_map, kva, kva + size);
+	if (pager_map_wanted)
+		wakeup(pager_map);
+	vm_map_unlock(pager_map);
+}
+
+vm_page_t
+vm_pager_atop(kva)
+	vm_offset_t	kva;
+{
+	vm_offset_t pa;
+
+	pa = pmap_extract(vm_map_pmap(pager_map), kva);
+	if (pa == 0)
+		panic("vm_pager_atop");
+	return (PHYS_TO_VM_PAGE(pa));
+}
+
+vm_pager_t
+vm_pager_lookup(pglist, handle)
+	register struct pagerlst *pglist;
+	caddr_t handle;
+{
+	register vm_pager_t pager;
+
+	for (pager = pglist->tqh_first; pager; pager = pager->pg_list.tqe_next)
+		if (pager->pg_handle == handle)
+			return (pager);
+	return (NULL);
+}
+
+/*
+ * This routine gains a reference to the object.
+ * Explicit deallocation is necessary.
+ */
+int
+pager_cache(object, should_cache)
+	vm_object_t	object;
+	boolean_t	should_cache;
+{
+	if (object == NULL)
+		return (KERN_INVALID_ARGUMENT);
+
+	vm_object_cache_lock();
+	vm_object_lock(object);
+	if (should_cache)
+		object->flags |= OBJ_CANPERSIST;
+	else
+		object->flags &= ~OBJ_CANPERSIST;
+	vm_object_unlock(object);
+	vm_object_cache_unlock();
+
+	vm_object_deallocate(object);
+
+	return (KERN_SUCCESS);
+}
diff --git a/sys/vm/vm_pager.h b/sys/vm/vm_pager.h
new file mode 100644
index 0000000..e4659c2
--- /dev/null
+++ b/sys/vm/vm_pager.h
@@ -0,0 +1,147 @@
+/*
+ * Copyright (c) 1990 University of Utah.
+ * Copyright (c) 1991, 1993
+ *	The Regents of the University of California.  All rights reserved.
+ *
+ * This code is derived from software contributed to Berkeley by
+ * the Systems Programming Group of the University of Utah Computer
+ * Science Department.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. All advertising materials mentioning features or use of this software
+ *    must display the following acknowledgement:
+ *	This product includes software developed by the University of
+ *	California, Berkeley and its contributors.
+ * 4. Neither the name of the University nor the names of its contributors
+ *    may be used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ *
+ *	@(#)vm_pager.h	8.4 (Berkeley) 1/12/94
+ */
+
+/*
+ * Pager routine interface definition.
+ * For BSD we use a cleaner version of the internal pager interface.
+ */
+
+#ifndef	_VM_PAGER_
+#define	_VM_PAGER_
+
+TAILQ_HEAD(pagerlst, pager_struct);
+
+struct	pager_struct {
+	TAILQ_ENTRY(pager_struct) pg_list;	/* links for list management */
+	caddr_t			  pg_handle;	/* ext. handle (vp, dev, fp) */
+	int			  pg_type;	/* type of pager */
+	int			  pg_flags;	/* flags */
+	struct pagerops		  *pg_ops;	/* pager operations */
+	void			  *pg_data;	/* private pager data */
+};
+
+/* pager types */
+#define PG_DFLT		-1
+#define	PG_SWAP		0
+#define	PG_VNODE	1
+#define PG_DEVICE	2
+
+/* flags */
+#define PG_CLUSTERGET	1
+#define PG_CLUSTERPUT	2
+
+struct	pagerops {
+	void		(*pgo_init)		/* Initialize pager. */
+			    __P((void));
+	vm_pager_t	(*pgo_alloc)		/* Allocate pager. */
+			    __P((caddr_t, vm_size_t, vm_prot_t, vm_offset_t));
+	void		(*pgo_dealloc)		/* Disassociate. */
+			    __P((vm_pager_t));
+	int		(*pgo_getpages)		/* Get (read) page. */
+			    __P((vm_pager_t, vm_page_t *, int, boolean_t));
+	int		(*pgo_putpages)		/* Put (write) page. */
+			    __P((vm_pager_t, vm_page_t *, int, boolean_t));
+	boolean_t  	(*pgo_haspage)		/* Does pager have page? */
+			    __P((vm_pager_t, vm_offset_t));
+	void		(*pgo_cluster)		/* Return range of cluster. */
+			    __P((vm_pager_t, vm_offset_t,
+				 vm_offset_t *, vm_offset_t *));
+};
+
+/*
+ * get/put return values
+ * OK	 operation was successful
+ * BAD	 specified data was out of the accepted range
+ * FAIL	 specified data was in range, but doesn't exist
+ * PEND	 operations was initiated but not completed
+ * ERROR error while accessing data that is in range and exists
+ * AGAIN temporary resource shortage prevented operation from happening
+ */
+#define	VM_PAGER_OK	0
+#define	VM_PAGER_BAD	1
+#define	VM_PAGER_FAIL	2
+#define	VM_PAGER_PEND	3
+#define	VM_PAGER_ERROR	4
+#define VM_PAGER_AGAIN	5
+
+#ifdef KERNEL
+extern struct pagerops *dfltpagerops;
+
+vm_pager_t	 vm_pager_allocate
+		    __P((int, caddr_t, vm_size_t, vm_prot_t, vm_offset_t));
+vm_page_t	 vm_pager_atop __P((vm_offset_t));
+void		 vm_pager_cluster
+		    __P((vm_pager_t, vm_offset_t,
+			 vm_offset_t *, vm_offset_t *));
+void		 vm_pager_clusternull
+		    __P((vm_pager_t, vm_offset_t,
+			 vm_offset_t *, vm_offset_t *));
+void		 vm_pager_deallocate __P((vm_pager_t));
+int		 vm_pager_get_pages
+		    __P((vm_pager_t, vm_page_t *, int, boolean_t));
+boolean_t	 vm_pager_has_page __P((vm_pager_t, vm_offset_t));
+void		 vm_pager_init __P((void));
+vm_pager_t	 vm_pager_lookup __P((struct pagerlst *, caddr_t));
+vm_offset_t	 vm_pager_map_pages __P((vm_page_t *, int, boolean_t));
+int		 vm_pager_put_pages
+		    __P((vm_pager_t, vm_page_t *, int, boolean_t));
+void		 vm_pager_sync __P((void));
+void		 vm_pager_unmap_pages __P((vm_offset_t, int));
+
+#define vm_pager_cancluster(p, b)	((p)->pg_flags & (b))
+
+/*
+ * XXX compat with old interface
+ */
+#define vm_pager_get(p, m, s) \
+({ \
+	vm_page_t ml[1]; \
+	ml[0] = (m); \
+	vm_pager_get_pages(p, ml, 1, s); \
+})
+#define vm_pager_put(p, m, s) \
+({ \
+	vm_page_t ml[1]; \
+	ml[0] = (m); \
+	vm_pager_put_pages(p, ml, 1, s); \
+})
+#endif
+
+#endif	/* _VM_PAGER_ */
diff --git a/sys/vm/vm_param.h b/sys/vm/vm_param.h
new file mode 100644
index 0000000..2d2c715
--- /dev/null
+++ b/sys/vm/vm_param.h
@@ -0,0 +1,159 @@
+/* 
+ * Copyright (c) 1991, 1993
+ *	The Regents of the University of California.  All rights reserved.
+ *
+ * This code is derived from software contributed to Berkeley by
+ * The Mach Operating System project at Carnegie-Mellon University.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. All advertising materials mentioning features or use of this software
+ *    must display the following acknowledgement:
+ *	This product includes software developed by the University of
+ *	California, Berkeley and its contributors.
+ * 4. Neither the name of the University nor the names of its contributors
+ *    may be used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ *
+ *	@(#)vm_param.h	8.1 (Berkeley) 6/11/93
+ *
+ *
+ * Copyright (c) 1987, 1990 Carnegie-Mellon University.
+ * All rights reserved.
+ *
+ * Authors: Avadis Tevanian, Jr., Michael Wayne Young
+ * 
+ * Permission to use, copy, modify and distribute this software and
+ * its documentation is hereby granted, provided that both the copyright
+ * notice and this permission notice appear in all copies of the
+ * software, derivative works or modified versions, and any portions
+ * thereof, and that both notices appear in supporting documentation.
+ * 
+ * CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS" 
+ * CONDITION.  CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND 
+ * FOR ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
+ * 
+ * Carnegie Mellon requests users of this software to return to
+ *
+ *  Software Distribution Coordinator  or  Software.Distribution@CS.CMU.EDU
+ *  School of Computer Science
+ *  Carnegie Mellon University
+ *  Pittsburgh PA 15213-3890
+ *
+ * any improvements or extensions that they make and grant Carnegie the
+ * rights to redistribute these changes.
+ */
+
+/*
+ *	Machine independent virtual memory parameters.
+ */
+
+#ifndef	_VM_PARAM_
+#define	_VM_PARAM_
+
+#include <machine/vmparam.h>
+
+/*
+ * This belongs in types.h, but breaks too many existing programs.
+ */
+typedef int	boolean_t;
+#define	TRUE	1
+#define	FALSE	0
+
+/*
+ *	The machine independent pages are refered to as PAGES.  A page
+ *	is some number of hardware pages, depending on the target machine.
+ */
+#define DEFAULT_PAGE_SIZE	4096
+
+/*
+ *	All references to the size of a page should be done with PAGE_SIZE
+ *	or PAGE_SHIFT.  The fact they are variables is hidden here so that
+ *	we can easily make them constant if we so desire.
+ */
+#define	PAGE_SIZE	cnt.v_page_size		/* size of page */
+#define PAGE_MASK	page_mask		/* size of page - 1 */
+#define PAGE_SHIFT	page_shift		/* bits to shift for pages */
+#ifdef KERNEL
+extern vm_size_t	page_mask;
+extern int		page_shift;
+#endif
+
+/*
+ * CTL_VM identifiers
+ */
+#define	VM_METER	 1		/* struct vmmeter */
+#define	VM_LOADAVG	 2		/* struct loadavg */
+#define	VM_MAXID	 3		/* number of valid vm ids */
+
+#define CTL_VM_NAMES { \
+	{ 0, 0 }, \
+	{ "vmmeter", CTLTYPE_STRUCT }, \
+	{ "loadavg", CTLTYPE_STRUCT }, \
+}
+
+/* 
+ *	Return values from the VM routines.
+ */
+#define	KERN_SUCCESS		0
+#define	KERN_INVALID_ADDRESS	1
+#define	KERN_PROTECTION_FAILURE	2
+#define	KERN_NO_SPACE		3
+#define	KERN_INVALID_ARGUMENT	4
+#define	KERN_FAILURE		5
+#define	KERN_RESOURCE_SHORTAGE	6
+#define	KERN_NOT_RECEIVER	7
+#define	KERN_NO_ACCESS		8
+
+#ifndef ASSEMBLER
+/*
+ *	Convert addresses to pages and vice versa.
+ *	No rounding is used.
+ */
+#ifdef KERNEL
+#define	atop(x)		(((unsigned)(x)) >> PAGE_SHIFT)
+#define	ptoa(x)		((vm_offset_t)((x) << PAGE_SHIFT))
+
+/*
+ * Round off or truncate to the nearest page.  These will work
+ * for either addresses or counts (i.e., 1 byte rounds to 1 page).
+ */
+#define round_page(x) \
+	((vm_offset_t)((((vm_offset_t)(x)) + PAGE_MASK) & ~PAGE_MASK))
+#define trunc_page(x) \
+	((vm_offset_t)(((vm_offset_t)(x)) & ~PAGE_MASK))
+#define num_pages(x) \
+	((vm_offset_t)((((vm_offset_t)(x)) + PAGE_MASK) >> PAGE_SHIFT))
+
+extern vm_size_t	mem_size;	/* size of physical memory (bytes) */
+extern vm_offset_t	first_addr;	/* first physical page */
+extern vm_offset_t	last_addr;	/* last physical page */
+
+#else
+/* out-of-kernel versions of round_page and trunc_page */
+#define	round_page(x) \
+       ((((vm_offset_t)(x) + (vm_page_size - 1)) / vm_page_size) * vm_page_size)
+#define	trunc_page(x) \
+	((((vm_offset_t)(x)) / vm_page_size) * vm_page_size)
+
+#endif /* KERNEL */
+#endif /* ASSEMBLER */
+#endif /* _VM_PARAM_ */
diff --git a/sys/vm/vm_prot.h b/sys/vm/vm_prot.h
new file mode 100644
index 0000000..b3bae43
--- /dev/null
+++ b/sys/vm/vm_prot.h
@@ -0,0 +1,102 @@
+/* 
+ * Copyright (c) 1991, 1993
+ *	The Regents of the University of California.  All rights reserved.
+ *
+ * This code is derived from software contributed to Berkeley by
+ * The Mach Operating System project at Carnegie-Mellon University.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. All advertising materials mentioning features or use of this software
+ *    must display the following acknowledgement:
+ *	This product includes software developed by the University of
+ *	California, Berkeley and its contributors.
+ * 4. Neither the name of the University nor the names of its contributors
+ *    may be used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ *
+ *	@(#)vm_prot.h	8.1 (Berkeley) 6/11/93
+ *
+ *
+ * Copyright (c) 1987, 1990 Carnegie-Mellon University.
+ * All rights reserved.
+ *
+ * Authors: Avadis Tevanian, Jr., Michael Wayne Young
+ * 
+ * Permission to use, copy, modify and distribute this software and
+ * its documentation is hereby granted, provided that both the copyright
+ * notice and this permission notice appear in all copies of the
+ * software, derivative works or modified versions, and any portions
+ * thereof, and that both notices appear in supporting documentation.
+ * 
+ * CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS" 
+ * CONDITION.  CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND 
+ * FOR ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
+ * 
+ * Carnegie Mellon requests users of this software to return to
+ *
+ *  Software Distribution Coordinator  or  Software.Distribution@CS.CMU.EDU
+ *  School of Computer Science
+ *  Carnegie Mellon University
+ *  Pittsburgh PA 15213-3890
+ *
+ * any improvements or extensions that they make and grant Carnegie the
+ * rights to redistribute these changes.
+ */
+
+/*
+ *	Virtual memory protection definitions.
+ */
+
+#ifndef	_VM_PROT_
+#define	_VM_PROT_
+
+/*
+ *	Types defined:
+ *
+ *	vm_prot_t		VM protection values.
+ */
+
+typedef int		vm_prot_t;
+
+/*
+ *	Protection values, defined as bits within the vm_prot_t type
+ */
+
+#define	VM_PROT_NONE	((vm_prot_t) 0x00)
+
+#define VM_PROT_READ	((vm_prot_t) 0x01)	/* read permission */
+#define VM_PROT_WRITE	((vm_prot_t) 0x02)	/* write permission */
+#define VM_PROT_EXECUTE	((vm_prot_t) 0x04)	/* execute permission */
+
+/*
+ *	The default protection for newly-created virtual memory
+ */
+
+#define VM_PROT_DEFAULT	(VM_PROT_READ|VM_PROT_WRITE|VM_PROT_EXECUTE)
+
+/*
+ *	The maximum privileges possible, for parameter checking.
+ */
+
+#define VM_PROT_ALL	(VM_PROT_READ|VM_PROT_WRITE|VM_PROT_EXECUTE)
+
+#endif /* _VM_PROT_ */
diff --git a/sys/vm/vm_swap.c b/sys/vm/vm_swap.c
new file mode 100644
index 0000000..10b7523
--- /dev/null
+++ b/sys/vm/vm_swap.c
@@ -0,0 +1,427 @@
+/*
+ * Copyright (c) 1982, 1986, 1989, 1993
+ *	The Regents of the University of California.  All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. All advertising materials mentioning features or use of this software
+ *    must display the following acknowledgement:
+ *	This product includes software developed by the University of
+ *	California, Berkeley and its contributors.
+ * 4. Neither the name of the University nor the names of its contributors
+ *    may be used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ *
+ *	@(#)vm_swap.c	8.5 (Berkeley) 2/17/94
+ */
+
+#include <sys/param.h>
+#include <sys/systm.h>
+#include <sys/buf.h>
+#include <sys/conf.h>
+#include <sys/proc.h>
+#include <sys/namei.h>
+#include <sys/dmap.h>		/* XXX */
+#include <sys/vnode.h>
+#include <sys/map.h>
+#include <sys/file.h>
+
+#include <miscfs/specfs/specdev.h>
+
+/*
+ * Indirect driver for multi-controller paging.
+ */
+
+int	nswap, nswdev;
+#ifdef SEQSWAP
+int	niswdev;		/* number of interleaved swap devices */
+int	niswap;			/* size of interleaved swap area */
+#endif
+
+/*
+ * Set up swap devices.
+ * Initialize linked list of free swap
+ * headers. These do not actually point
+ * to buffers, but rather to pages that
+ * are being swapped in and out.
+ */
+void
+swapinit()
+{
+	register int i;
+	register struct buf *sp = swbuf;
+	register struct proc *p = &proc0;	/* XXX */
+	struct swdevt *swp;
+	int error;
+
+	/*
+	 * Count swap devices, and adjust total swap space available.
+	 * Some of the space will not be countable until later (dynamically
+	 * configurable devices) and some of the counted space will not be
+	 * available until a swapon() system call is issued, both usually
+	 * happen when the system goes multi-user.
+	 *
+	 * If using NFS for swap, swdevt[0] will already be bdevvp'd.	XXX
+	 */
+#ifdef SEQSWAP
+	nswdev = niswdev = 0;
+	nswap = niswap = 0;
+	/*
+	 * All interleaved devices must come first
+	 */
+	for (swp = swdevt; swp->sw_dev != NODEV || swp->sw_vp != NULL; swp++) {
+		if (swp->sw_flags & SW_SEQUENTIAL)
+			break;
+		niswdev++;
+		if (swp->sw_nblks > niswap)
+			niswap = swp->sw_nblks;
+	}
+	niswap = roundup(niswap, dmmax);
+	niswap *= niswdev;
+	if (swdevt[0].sw_vp == NULL &&
+	    bdevvp(swdevt[0].sw_dev, &swdevt[0].sw_vp))
+		panic("swapvp");
+	/*
+	 * The remainder must be sequential
+	 */
+	for ( ; swp->sw_dev != NODEV; swp++) {
+		if ((swp->sw_flags & SW_SEQUENTIAL) == 0)
+			panic("binit: mis-ordered swap devices");
+		nswdev++;
+		if (swp->sw_nblks > 0) {
+			if (swp->sw_nblks % dmmax)
+				swp->sw_nblks -= (swp->sw_nblks % dmmax);
+			nswap += swp->sw_nblks;
+		}
+	}
+	nswdev += niswdev;
+	if (nswdev == 0)
+		panic("swapinit");
+	nswap += niswap;
+#else
+	nswdev = 0;
+	nswap = 0;
+	for (swp = swdevt; swp->sw_dev != NODEV || swp->sw_vp != NULL; swp++) {
+		nswdev++;
+		if (swp->sw_nblks > nswap)
+			nswap = swp->sw_nblks;
+	}
+	if (nswdev == 0)
+		panic("swapinit");
+	if (nswdev > 1)
+		nswap = ((nswap + dmmax - 1) / dmmax) * dmmax;
+	nswap *= nswdev;
+	if (swdevt[0].sw_vp == NULL &&
+	    bdevvp(swdevt[0].sw_dev, &swdevt[0].sw_vp))
+		panic("swapvp");
+#endif
+	if (nswap == 0)
+		printf("WARNING: no swap space found\n");
+	else if (error = swfree(p, 0)) {
+		printf("swfree errno %d\n", error);	/* XXX */
+		panic("swapinit swfree 0");
+	}
+
+	/*
+	 * Now set up swap buffer headers.
+	 */
+	bswlist.b_actf = sp;
+	for (i = 0; i < nswbuf - 1; i++, sp++) {
+		sp->b_actf = sp + 1;
+		sp->b_rcred = sp->b_wcred = p->p_ucred;
+		sp->b_vnbufs.le_next = NOLIST;
+	}
+	sp->b_rcred = sp->b_wcred = p->p_ucred;
+	sp->b_vnbufs.le_next = NOLIST;
+	sp->b_actf = NULL;
+}
+
+void
+swstrategy(bp)
+	register struct buf *bp;
+{
+	int sz, off, seg, index;
+	register struct swdevt *sp;
+	struct vnode *vp;
+
+#ifdef GENERIC
+	/*
+	 * A mini-root gets copied into the front of the swap
+	 * and we run over top of the swap area just long
+	 * enough for us to do a mkfs and restor of the real
+	 * root (sure beats rewriting standalone restor).
+	 */
+#define	MINIROOTSIZE	4096
+	if (rootdev == dumpdev)
+		bp->b_blkno += MINIROOTSIZE;
+#endif
+	sz = howmany(bp->b_bcount, DEV_BSIZE);
+	if (bp->b_blkno + sz > nswap) {
+		bp->b_error = EINVAL;
+		bp->b_flags |= B_ERROR;
+		biodone(bp);
+		return;
+	}
+	if (nswdev > 1) {
+#ifdef SEQSWAP
+		if (bp->b_blkno < niswap) {
+			if (niswdev > 1) {
+				off = bp->b_blkno % dmmax;
+				if (off+sz > dmmax) {
+					bp->b_error = EINVAL;
+					bp->b_flags |= B_ERROR;
+					biodone(bp);
+					return;
+				}
+				seg = bp->b_blkno / dmmax;
+				index = seg % niswdev;
+				seg /= niswdev;
+				bp->b_blkno = seg*dmmax + off;
+			} else
+				index = 0;
+		} else {
+			register struct swdevt *swp;
+
+			bp->b_blkno -= niswap;
+			for (index = niswdev, swp = &swdevt[niswdev];
+			     swp->sw_dev != NODEV;
+			     swp++, index++) {
+				if (bp->b_blkno < swp->sw_nblks)
+					break;
+				bp->b_blkno -= swp->sw_nblks;
+			}
+			if (swp->sw_dev == NODEV ||
+			    bp->b_blkno+sz > swp->sw_nblks) {
+				bp->b_error = swp->sw_dev == NODEV ?
+					ENODEV : EINVAL;
+				bp->b_flags |= B_ERROR;
+				biodone(bp);
+				return;
+			}
+		}
+#else
+		off = bp->b_blkno % dmmax;
+		if (off+sz > dmmax) {
+			bp->b_error = EINVAL;
+			bp->b_flags |= B_ERROR;
+			biodone(bp);
+			return;
+		}
+		seg = bp->b_blkno / dmmax;
+		index = seg % nswdev;
+		seg /= nswdev;
+		bp->b_blkno = seg*dmmax + off;
+#endif
+	} else
+		index = 0;
+	sp = &swdevt[index];
+	if ((bp->b_dev = sp->sw_dev) == NODEV)
+		panic("swstrategy");
+	if (sp->sw_vp == NULL) {
+		bp->b_error = ENODEV;
+		bp->b_flags |= B_ERROR;
+		biodone(bp);
+		return;
+	}
+	VHOLD(sp->sw_vp);
+	if ((bp->b_flags & B_READ) == 0) {
+		if (vp = bp->b_vp) {
+			vp->v_numoutput--;
+			if ((vp->v_flag & VBWAIT) && vp->v_numoutput <= 0) {
+				vp->v_flag &= ~VBWAIT;
+				wakeup((caddr_t)&vp->v_numoutput);
+			}
+		}
+		sp->sw_vp->v_numoutput++;
+	}
+	if (bp->b_vp != NULL)
+		brelvp(bp);
+	bp->b_vp = sp->sw_vp;
+	VOP_STRATEGY(bp);
+}
+
+/*
+ * System call swapon(name) enables swapping on device name,
+ * which must be in the swdevsw.  Return EBUSY
+ * if already swapping on this device.
+ */
+struct swapon_args {
+	char	*name;
+};
+/* ARGSUSED */
+int
+swapon(p, uap, retval)
+	struct proc *p;
+	struct swapon_args *uap;
+	int *retval;
+{
+	register struct vnode *vp;
+	register struct swdevt *sp;
+	dev_t dev;
+	int error;
+	struct nameidata nd;
+
+	if (error = suser(p->p_ucred, &p->p_acflag))
+		return (error);
+	NDINIT(&nd, LOOKUP, FOLLOW, UIO_USERSPACE, uap->name, p);
+	if (error = namei(&nd))
+		return (error);
+	vp = nd.ni_vp;
+	if (vp->v_type != VBLK) {
+		vrele(vp);
+		return (ENOTBLK);
+	}
+	dev = (dev_t)vp->v_rdev;
+	if (major(dev) >= nblkdev) {
+		vrele(vp);
+		return (ENXIO);
+	}
+	for (sp = &swdevt[0]; sp->sw_dev != NODEV; sp++) {
+		if (sp->sw_dev == dev) {
+			if (sp->sw_flags & SW_FREED) {
+				vrele(vp);
+				return (EBUSY);
+			}
+			sp->sw_vp = vp;
+			if (error = swfree(p, sp - swdevt)) {
+				vrele(vp);
+				return (error);
+			}
+			return (0);
+		}
+#ifdef SEQSWAP
+		/*
+		 * If we have reached a non-freed sequential device without
+		 * finding what we are looking for, it is an error.
+		 * That is because all interleaved devices must come first
+		 * and sequential devices must be freed in order.
+		 */
+		if ((sp->sw_flags & (SW_SEQUENTIAL|SW_FREED)) == SW_SEQUENTIAL)
+			break;
+#endif
+	}
+	vrele(vp);
+	return (EINVAL);
+}
+
+/*
+ * Swfree(index) frees the index'th portion of the swap map.
+ * Each of the nswdev devices provides 1/nswdev'th of the swap
+ * space, which is laid out with blocks of dmmax pages circularly
+ * among the devices.
+ */
+int
+swfree(p, index)
+	struct proc *p;
+	int index;
+{
+	register struct swdevt *sp;
+	register swblk_t vsbase;
+	register long blk;
+	struct vnode *vp;
+	register swblk_t dvbase;
+	register int nblks;
+	int error;
+
+	sp = &swdevt[index];
+	vp = sp->sw_vp;
+	if (error = VOP_OPEN(vp, FREAD|FWRITE, p->p_ucred, p))
+		return (error);
+	sp->sw_flags |= SW_FREED;
+	nblks = sp->sw_nblks;
+	/*
+	 * Some devices may not exist til after boot time.
+	 * If so, their nblk count will be 0.
+	 */
+	if (nblks <= 0) {
+		int perdev;
+		dev_t dev = sp->sw_dev;
+
+		if (bdevsw[major(dev)].d_psize == 0 ||
+		    (nblks = (*bdevsw[major(dev)].d_psize)(dev)) == -1) {
+			(void) VOP_CLOSE(vp, FREAD|FWRITE, p->p_ucred, p);
+			sp->sw_flags &= ~SW_FREED;
+			return (ENXIO);
+		}
+#ifdef SEQSWAP
+		if (index < niswdev) {
+			perdev = niswap / niswdev;
+			if (nblks > perdev)
+				nblks = perdev;
+		} else {
+			if (nblks % dmmax)
+				nblks -= (nblks % dmmax);
+			nswap += nblks;
+		}
+#else
+		perdev = nswap / nswdev;
+		if (nblks > perdev)
+			nblks = perdev;
+#endif
+		sp->sw_nblks = nblks;
+	}
+	if (nblks == 0) {
+		(void) VOP_CLOSE(vp, FREAD|FWRITE, p->p_ucred, p);
+		sp->sw_flags &= ~SW_FREED;
+		return (0);	/* XXX error? */
+	}
+#ifdef SEQSWAP
+	if (sp->sw_flags & SW_SEQUENTIAL) {
+		register struct swdevt *swp;
+
+		blk = niswap;
+		for (swp = &swdevt[niswdev]; swp != sp; swp++)
+			blk += swp->sw_nblks;
+		rmfree(swapmap, nblks, blk);
+		return (0);
+	}
+#endif
+	for (dvbase = 0; dvbase < nblks; dvbase += dmmax) {
+		blk = nblks - dvbase;
+#ifdef SEQSWAP
+		if ((vsbase = index*dmmax + dvbase*niswdev) >= niswap)
+			panic("swfree");
+#else
+		if ((vsbase = index*dmmax + dvbase*nswdev) >= nswap)
+			panic("swfree");
+#endif
+		if (blk > dmmax)
+			blk = dmmax;
+		if (vsbase == 0) {
+			/*
+			 * First of all chunks... initialize the swapmap.
+			 * Don't use the first cluster of the device
+			 * in case it starts with a label or boot block.
+			 */
+			rminit(swapmap, blk - ctod(CLSIZE),
+			    vsbase + ctod(CLSIZE), "swap", nswapmap);
+		} else if (dvbase == 0) {
+			/*
+			 * Don't use the first cluster of the device
+			 * in case it starts with a label or boot block.
+			 */
+			rmfree(swapmap, blk - ctod(CLSIZE),
+			    vsbase + ctod(CLSIZE));
+		} else
+			rmfree(swapmap, blk, vsbase);
+	}
+	return (0);
+}
diff --git a/sys/vm/vm_unix.c b/sys/vm/vm_unix.c
new file mode 100644
index 0000000..3d49ea7
--- /dev/null
+++ b/sys/vm/vm_unix.c
@@ -0,0 +1,137 @@
+/*
+ * Copyright (c) 1988 University of Utah.
+ * Copyright (c) 1991, 1993
+ *	The Regents of the University of California.  All rights reserved.
+ *
+ * This code is derived from software contributed to Berkeley by
+ * the Systems Programming Group of the University of Utah Computer
+ * Science Department.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. All advertising materials mentioning features or use of this software
+ *    must display the following acknowledgement:
+ *	This product includes software developed by the University of
+ *	California, Berkeley and its contributors.
+ * 4. Neither the name of the University nor the names of its contributors
+ *    may be used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ *
+ * from: Utah $Hdr: vm_unix.c 1.1 89/11/07$
+ *
+ *	@(#)vm_unix.c	8.1 (Berkeley) 6/11/93
+ */
+
+/*
+ * Traditional sbrk/grow interface to VM
+ */
+#include <sys/param.h>
+#include <sys/systm.h>
+#include <sys/proc.h>
+#include <sys/resourcevar.h>
+
+#include <vm/vm.h>
+
+struct obreak_args {
+	char	*nsiz;
+};
+/* ARGSUSED */
+int
+obreak(p, uap, retval)
+	struct proc *p;
+	struct obreak_args *uap;
+	int *retval;
+{
+	register struct vmspace *vm = p->p_vmspace;
+	vm_offset_t new, old;
+	int rv;
+	register int diff;
+
+	old = (vm_offset_t)vm->vm_daddr;
+	new = round_page(uap->nsiz);
+	if ((int)(new - old) > p->p_rlimit[RLIMIT_DATA].rlim_cur)
+		return(ENOMEM);
+	old = round_page(old + ctob(vm->vm_dsize));
+	diff = new - old;
+	if (diff > 0) {
+		rv = vm_allocate(&vm->vm_map, &old, diff, FALSE);
+		if (rv != KERN_SUCCESS) {
+			uprintf("sbrk: grow failed, return = %d\n", rv);
+			return(ENOMEM);
+		}
+		vm->vm_dsize += btoc(diff);
+	} else if (diff < 0) {
+		diff = -diff;
+		rv = vm_deallocate(&vm->vm_map, new, diff);
+		if (rv != KERN_SUCCESS) {
+			uprintf("sbrk: shrink failed, return = %d\n", rv);
+			return(ENOMEM);
+		}
+		vm->vm_dsize -= btoc(diff);
+	}
+	return(0);
+}
+
+/*
+ * Enlarge the "stack segment" to include the specified
+ * stack pointer for the process.
+ */
+int
+grow(p, sp)
+	struct proc *p;
+	unsigned sp;
+{
+	register struct vmspace *vm = p->p_vmspace;
+	register int si;
+
+	/*
+	 * For user defined stacks (from sendsig).
+	 */
+	if (sp < (unsigned)vm->vm_maxsaddr)
+		return (0);
+	/*
+	 * For common case of already allocated (from trap).
+	 */
+	if (sp >= USRSTACK - ctob(vm->vm_ssize))
+		return (1);
+	/*
+	 * Really need to check vs limit and increment stack size if ok.
+	 */
+	si = clrnd(btoc(USRSTACK-sp) - vm->vm_ssize);
+	if (vm->vm_ssize + si > btoc(p->p_rlimit[RLIMIT_STACK].rlim_cur))
+		return (0);
+	vm->vm_ssize += si;
+	return (1);
+}
+
+struct ovadvise_args {
+	int	anom;
+};
+/* ARGSUSED */
+int
+ovadvise(p, uap, retval)
+	struct proc *p;
+	struct ovadvise_args *uap;
+	int *retval;
+{
+
+	return (EINVAL);
+}
diff --git a/sys/vm/vm_user.c b/sys/vm/vm_user.c
new file mode 100644
index 0000000..20172c6
--- /dev/null
+++ b/sys/vm/vm_user.c
@@ -0,0 +1,312 @@
+/* 
+ * Copyright (c) 1991, 1993
+ *	The Regents of the University of California.  All rights reserved.
+ *
+ * This code is derived from software contributed to Berkeley by
+ * The Mach Operating System project at Carnegie-Mellon University.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. All advertising materials mentioning features or use of this software
+ *    must display the following acknowledgement:
+ *	This product includes software developed by the University of
+ *	California, Berkeley and its contributors.
+ * 4. Neither the name of the University nor the names of its contributors
+ *    may be used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ *
+ *	@(#)vm_user.c	8.2 (Berkeley) 1/12/94
+ *
+ *
+ * Copyright (c) 1987, 1990 Carnegie-Mellon University.
+ * All rights reserved.
+ *
+ * Authors: Avadis Tevanian, Jr., Michael Wayne Young
+ * 
+ * Permission to use, copy, modify and distribute this software and
+ * its documentation is hereby granted, provided that both the copyright
+ * notice and this permission notice appear in all copies of the
+ * software, derivative works or modified versions, and any portions
+ * thereof, and that both notices appear in supporting documentation.
+ * 
+ * CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS" 
+ * CONDITION.  CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND 
+ * FOR ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
+ * 
+ * Carnegie Mellon requests users of this software to return to
+ *
+ *  Software Distribution Coordinator  or  Software.Distribution@CS.CMU.EDU
+ *  School of Computer Science
+ *  Carnegie Mellon University
+ *  Pittsburgh PA 15213-3890
+ *
+ * any improvements or extensions that they make and grant Carnegie the
+ * rights to redistribute these changes.
+ */
+
+/*
+ *	User-exported virtual memory functions.
+ */
+
+#include <sys/param.h>
+#include <sys/systm.h>
+#include <sys/proc.h>
+
+#include <vm/vm.h>
+
+simple_lock_data_t	vm_alloc_lock;	/* XXX */
+
+#ifdef MACHVMCOMPAT
+/*
+ * BSD style syscall interfaces to MACH calls
+ * All return MACH return values.
+ */
+struct svm_allocate_args {
+	vm_map_t map;
+	vm_offset_t *addr;
+	vm_size_t size;
+	boolean_t anywhere;
+};
+/* ARGSUSED */
+int
+svm_allocate(p, uap, retval)
+	struct proc *p;
+	struct svm_allocate_args *uap;
+	int *retval;
+{
+	vm_offset_t addr;
+	int rv;
+
+	uap->map = p->p_map;		/* XXX */
+
+	if (copyin((caddr_t)uap->addr, (caddr_t)&addr, sizeof (addr)))
+		rv = KERN_INVALID_ARGUMENT;
+	else
+		rv = vm_allocate(uap->map, &addr, uap->size, uap->anywhere);
+	if (rv == KERN_SUCCESS) {
+		if (copyout((caddr_t)&addr, (caddr_t)uap->addr, sizeof(addr)))
+			rv = KERN_INVALID_ARGUMENT;
+	}
+	return((int)rv);
+}
+
+struct svm_deallocate_args {
+	vm_map_t map;
+	vm_offset_t addr;
+	vm_size_t size;
+};
+/* ARGSUSED */
+int
+svm_deallocate(p, uap, retval)
+	struct proc *p;
+	struct svm_deallocate_args *uap;
+	int *retval;
+{
+	int rv;
+
+	uap->map = p->p_map;		/* XXX */
+	rv = vm_deallocate(uap->map, uap->addr, uap->size);
+	return((int)rv);
+}
+
+struct svm_inherit_args {
+	vm_map_t map;
+	vm_offset_t addr;
+	vm_size_t size;
+	vm_inherit_t inherit;
+};
+/* ARGSUSED */
+int
+svm_inherit(p, uap, retval)
+	struct proc *p;
+	struct svm_inherit_args *uap;
+	int *retval;
+{
+	int rv;
+
+	uap->map = p->p_map;		/* XXX */
+	rv = vm_inherit(uap->map, uap->addr, uap->size, uap->inherit);
+	return((int)rv);
+}
+
+struct svm_protect_args {
+	vm_map_t map;
+	vm_offset_t addr;
+	vm_size_t size;
+	boolean_t setmax;
+	vm_prot_t prot;
+};
+/* ARGSUSED */
+int
+svm_protect(p, uap, retval)
+	struct proc *p;
+	struct svm_protect_args *uap;
+	int *retval;
+{
+	int rv;
+
+	uap->map = p->p_map;		/* XXX */
+	rv = vm_protect(uap->map, uap->addr, uap->size, uap->setmax, uap->prot);
+	return((int)rv);
+}
+
+/*
+ *	vm_inherit sets the inheritence of the specified range in the
+ *	specified map.
+ */
+int
+vm_inherit(map, start, size, new_inheritance)
+	register vm_map_t	map;
+	vm_offset_t		start;
+	vm_size_t		size;
+	vm_inherit_t		new_inheritance;
+{
+	if (map == NULL)
+		return(KERN_INVALID_ARGUMENT);
+
+	return(vm_map_inherit(map, trunc_page(start), round_page(start+size), new_inheritance));
+}
+
+/*
+ *	vm_protect sets the protection of the specified range in the
+ *	specified map.
+ */
+
+int
+vm_protect(map, start, size, set_maximum, new_protection)
+	register vm_map_t	map;
+	vm_offset_t		start;
+	vm_size_t		size;
+	boolean_t		set_maximum;
+	vm_prot_t		new_protection;
+{
+	if (map == NULL)
+		return(KERN_INVALID_ARGUMENT);
+
+	return(vm_map_protect(map, trunc_page(start), round_page(start+size), new_protection, set_maximum));
+}
+#endif
+
+/*
+ *	vm_allocate allocates "zero fill" memory in the specfied
+ *	map.
+ */
+int
+vm_allocate(map, addr, size, anywhere)
+	register vm_map_t	map;
+	register vm_offset_t	*addr;
+	register vm_size_t	size;
+	boolean_t		anywhere;
+{
+	int	result;
+
+	if (map == NULL)
+		return(KERN_INVALID_ARGUMENT);
+	if (size == 0) {
+		*addr = 0;
+		return(KERN_SUCCESS);
+	}
+
+	if (anywhere)
+		*addr = vm_map_min(map);
+	else
+		*addr = trunc_page(*addr);
+	size = round_page(size);
+
+	result = vm_map_find(map, NULL, (vm_offset_t) 0, addr, size, anywhere);
+
+	return(result);
+}
+
+/*
+ *	vm_deallocate deallocates the specified range of addresses in the
+ *	specified address map.
+ */
+int
+vm_deallocate(map, start, size)
+	register vm_map_t	map;
+	vm_offset_t		start;
+	vm_size_t		size;
+{
+	if (map == NULL)
+		return(KERN_INVALID_ARGUMENT);
+
+	if (size == (vm_offset_t) 0)
+		return(KERN_SUCCESS);
+
+	return(vm_map_remove(map, trunc_page(start), round_page(start+size)));
+}
+
+/*
+ * Similar to vm_allocate but assigns an explicit pager.
+ */
+int
+vm_allocate_with_pager(map, addr, size, anywhere, pager, poffset, internal)
+	register vm_map_t	map;
+	register vm_offset_t	*addr;
+	register vm_size_t	size;
+	boolean_t		anywhere;
+	vm_pager_t		pager;
+	vm_offset_t		poffset;
+	boolean_t		internal;
+{
+	register vm_object_t	object;
+	register int		result;
+
+	if (map == NULL)
+		return(KERN_INVALID_ARGUMENT);
+
+	*addr = trunc_page(*addr);
+	size = round_page(size);
+
+	/*
+	 *	Lookup the pager/paging-space in the object cache.
+	 *	If it's not there, then create a new object and cache
+	 *	it.
+	 */
+	object = vm_object_lookup(pager);
+	cnt.v_lookups++;
+	if (object == NULL) {
+		object = vm_object_allocate(size);
+		/*
+		 * From Mike Hibler: "unnamed anonymous objects should never
+		 * be on the hash list ... For now you can just change
+		 * vm_allocate_with_pager to not do vm_object_enter if this
+		 * is an internal object ..."
+		 */
+		if (!internal)
+			vm_object_enter(object, pager);
+	} else
+		cnt.v_hits++;
+	if (internal)
+		object->flags |= OBJ_INTERNAL;
+	else {
+		object->flags &= ~OBJ_INTERNAL;
+		cnt.v_nzfod -= atop(size);
+	}
+
+	result = vm_map_find(map, object, poffset, addr, size, anywhere);
+	if (result != KERN_SUCCESS)
+		vm_object_deallocate(object);
+	else if (pager != NULL)
+		vm_object_setpager(object, pager, (vm_offset_t) 0, TRUE);
+	return(result);
+}
diff --git a/sys/vm/vnode_pager.c b/sys/vm/vnode_pager.c
new file mode 100644
index 0000000..9c2f826
--- /dev/null
+++ b/sys/vm/vnode_pager.c
@@ -0,0 +1,580 @@
+/*
+ * Copyright (c) 1990 University of Utah.
+ * Copyright (c) 1991, 1993
+ *	The Regents of the University of California.  All rights reserved.
+ *
+ * This code is derived from software contributed to Berkeley by
+ * the Systems Programming Group of the University of Utah Computer
+ * Science Department.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. All advertising materials mentioning features or use of this software
+ *    must display the following acknowledgement:
+ *	This product includes software developed by the University of
+ *	California, Berkeley and its contributors.
+ * 4. Neither the name of the University nor the names of its contributors
+ *    may be used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ *
+ *	@(#)vnode_pager.c	8.8 (Berkeley) 2/13/94
+ */
+
+/*
+ * Page to/from files (vnodes).
+ *
+ * TODO:
+ *	pageouts
+ *	fix credential use (uses current process credentials now)
+ */
+
+#include <sys/param.h>
+#include <sys/systm.h>
+#include <sys/proc.h>
+#include <sys/malloc.h>
+#include <sys/vnode.h>
+#include <sys/uio.h>
+#include <sys/mount.h>
+
+#include <vm/vm.h>
+#include <vm/vm_page.h>
+#include <vm/vnode_pager.h>
+
+struct pagerlst	vnode_pager_list;	/* list of managed vnodes */
+
+#ifdef DEBUG
+int	vpagerdebug = 0x00;
+#define	VDB_FOLLOW	0x01
+#define VDB_INIT	0x02
+#define VDB_IO		0x04
+#define VDB_FAIL	0x08
+#define VDB_ALLOC	0x10
+#define VDB_SIZE	0x20
+#endif
+
+static vm_pager_t	 vnode_pager_alloc
+			    __P((caddr_t, vm_size_t, vm_prot_t, vm_offset_t));
+static void		 vnode_pager_cluster
+			    __P((vm_pager_t, vm_offset_t,
+				 vm_offset_t *, vm_offset_t *));
+static void		 vnode_pager_dealloc __P((vm_pager_t));
+static int		 vnode_pager_getpage
+			    __P((vm_pager_t, vm_page_t *, int, boolean_t));
+static boolean_t	 vnode_pager_haspage __P((vm_pager_t, vm_offset_t));
+static void		 vnode_pager_init __P((void));
+static int		 vnode_pager_io
+			    __P((vn_pager_t, vm_page_t *, int,
+				 boolean_t, enum uio_rw));
+static boolean_t	 vnode_pager_putpage
+			    __P((vm_pager_t, vm_page_t *, int, boolean_t));
+
+struct pagerops vnodepagerops = {
+	vnode_pager_init,
+	vnode_pager_alloc,
+	vnode_pager_dealloc,
+	vnode_pager_getpage,
+	vnode_pager_putpage,
+	vnode_pager_haspage,
+	vnode_pager_cluster
+};
+
+static void
+vnode_pager_init()
+{
+#ifdef DEBUG
+	if (vpagerdebug & VDB_FOLLOW)
+		printf("vnode_pager_init()\n");
+#endif
+	TAILQ_INIT(&vnode_pager_list);
+}
+
+/*
+ * Allocate (or lookup) pager for a vnode.
+ * Handle is a vnode pointer.
+ */
+static vm_pager_t
+vnode_pager_alloc(handle, size, prot, foff)
+	caddr_t handle;
+	vm_size_t size;
+	vm_prot_t prot;
+	vm_offset_t foff;
+{
+	register vm_pager_t pager;
+	register vn_pager_t vnp;
+	vm_object_t object;
+	struct vattr vattr;
+	struct vnode *vp;
+	struct proc *p = curproc;	/* XXX */
+
+#ifdef DEBUG
+	if (vpagerdebug & (VDB_FOLLOW|VDB_ALLOC))
+		printf("vnode_pager_alloc(%x, %x, %x)\n", handle, size, prot);
+#endif
+	/*
+	 * Pageout to vnode, no can do yet.
+	 */
+	if (handle == NULL)
+		return(NULL);
+
+	/*
+	 * Vnodes keep a pointer to any associated pager so no need to
+	 * lookup with vm_pager_lookup.
+	 */
+	vp = (struct vnode *)handle;
+	pager = (vm_pager_t)vp->v_vmdata;
+	if (pager == NULL) {
+		/*
+		 * Allocate pager structures
+		 */
+		pager = (vm_pager_t)malloc(sizeof *pager, M_VMPAGER, M_WAITOK);
+		if (pager == NULL)
+			return(NULL);
+		vnp = (vn_pager_t)malloc(sizeof *vnp, M_VMPGDATA, M_WAITOK);
+		if (vnp == NULL) {
+			free((caddr_t)pager, M_VMPAGER);
+			return(NULL);
+		}
+		/*
+		 * And an object of the appropriate size
+		 */
+		if (VOP_GETATTR(vp, &vattr, p->p_ucred, p) == 0) {
+			object = vm_object_allocate(round_page(vattr.va_size));
+			vm_object_enter(object, pager);
+			vm_object_setpager(object, pager, 0, TRUE);
+		} else {
+			free((caddr_t)vnp, M_VMPGDATA);
+			free((caddr_t)pager, M_VMPAGER);
+			return(NULL);
+		}
+		/*
+		 * Hold a reference to the vnode and initialize pager data.
+		 */
+		VREF(vp);
+		vnp->vnp_flags = 0;
+		vnp->vnp_vp = vp;
+		vnp->vnp_size = vattr.va_size;
+		TAILQ_INSERT_TAIL(&vnode_pager_list, pager, pg_list);
+		pager->pg_handle = handle;
+		pager->pg_type = PG_VNODE;
+		pager->pg_flags = 0;
+		pager->pg_ops = &vnodepagerops;
+		pager->pg_data = vnp;
+		vp->v_vmdata = (caddr_t)pager;
+	} else {
+		/*
+		 * vm_object_lookup() will remove the object from the
+		 * cache if found and also gain a reference to the object.
+		 */
+		object = vm_object_lookup(pager);
+#ifdef DEBUG
+		vnp = (vn_pager_t)pager->pg_data;
+#endif
+	}
+#ifdef DEBUG
+	if (vpagerdebug & VDB_ALLOC)
+		printf("vnode_pager_setup: vp %x sz %x pager %x object %x\n",
+		       vp, vnp->vnp_size, pager, object);
+#endif
+	return(pager);
+}
+
+static void
+vnode_pager_dealloc(pager)
+	vm_pager_t pager;
+{
+	register vn_pager_t vnp = (vn_pager_t)pager->pg_data;
+	register struct vnode *vp;
+#ifdef NOTDEF
+	struct proc *p = curproc;		/* XXX */
+#endif
+
+#ifdef DEBUG
+	if (vpagerdebug & VDB_FOLLOW)
+		printf("vnode_pager_dealloc(%x)\n", pager);
+#endif
+	if (vp = vnp->vnp_vp) {
+		vp->v_vmdata = NULL;
+		vp->v_flag &= ~VTEXT;
+#if NOTDEF
+		/* can hang if done at reboot on NFS FS */
+		(void) VOP_FSYNC(vp, p->p_ucred, p);
+#endif
+		vrele(vp);
+	}
+	TAILQ_REMOVE(&vnode_pager_list, pager, pg_list);
+	free((caddr_t)vnp, M_VMPGDATA);
+	free((caddr_t)pager, M_VMPAGER);
+}
+
+static int
+vnode_pager_getpage(pager, mlist, npages, sync)
+	vm_pager_t pager;
+	vm_page_t *mlist;
+	int npages;
+	boolean_t sync;
+{
+
+#ifdef DEBUG
+	if (vpagerdebug & VDB_FOLLOW)
+		printf("vnode_pager_getpage(%x, %x, %x, %x)\n",
+		       pager, mlist, npages, sync);
+#endif
+	return(vnode_pager_io((vn_pager_t)pager->pg_data,
+			      mlist, npages, sync, UIO_READ));
+}
+
+static boolean_t
+vnode_pager_putpage(pager, mlist, npages, sync)
+	vm_pager_t pager;
+	vm_page_t *mlist;
+	int npages;
+	boolean_t sync;
+{
+	int err;
+
+#ifdef DEBUG
+	if (vpagerdebug & VDB_FOLLOW)
+		printf("vnode_pager_putpage(%x, %x, %x, %x)\n",
+		       pager, mlist, npages, sync);
+#endif
+	if (pager == NULL)
+		return (FALSE);			/* ??? */
+	err = vnode_pager_io((vn_pager_t)pager->pg_data,
+			     mlist, npages, sync, UIO_WRITE);
+	/*
+	 * If the operation was successful, mark the pages clean.
+	 */
+	if (err == VM_PAGER_OK) {
+		while (npages--) {
+			(*mlist)->flags |= PG_CLEAN;
+			pmap_clear_modify(VM_PAGE_TO_PHYS(*mlist));
+			mlist++;
+		}
+	}
+	return(err);
+}
+
+static boolean_t
+vnode_pager_haspage(pager, offset)
+	vm_pager_t pager;
+	vm_offset_t offset;
+{
+	register vn_pager_t vnp = (vn_pager_t)pager->pg_data;
+	daddr_t bn;
+	int err;
+
+#ifdef DEBUG
+	if (vpagerdebug & VDB_FOLLOW)
+		printf("vnode_pager_haspage(%x, %x)\n", pager, offset);
+#endif
+
+	/*
+	 * Offset beyond end of file, do not have the page
+	 * Lock the vnode first to make sure we have the most recent
+	 * version of the size.
+	 */
+	VOP_LOCK(vnp->vnp_vp);
+	if (offset >= vnp->vnp_size) {
+		VOP_UNLOCK(vnp->vnp_vp);
+#ifdef DEBUG
+		if (vpagerdebug & (VDB_FAIL|VDB_SIZE))
+			printf("vnode_pager_haspage: pg %x, off %x, size %x\n",
+			       pager, offset, vnp->vnp_size);
+#endif
+		return(FALSE);
+	}
+
+	/*
+	 * Read the index to find the disk block to read
+	 * from.  If there is no block, report that we don't
+	 * have this data.
+	 *
+	 * Assumes that the vnode has whole page or nothing.
+	 */
+	err = VOP_BMAP(vnp->vnp_vp,
+		       offset / vnp->vnp_vp->v_mount->mnt_stat.f_iosize,
+		       (struct vnode **)0, &bn, NULL);
+	VOP_UNLOCK(vnp->vnp_vp);
+	if (err) {
+#ifdef DEBUG
+		if (vpagerdebug & VDB_FAIL)
+			printf("vnode_pager_haspage: BMAP err %d, pg %x, off %x\n",
+			       err, pager, offset);
+#endif
+		return(TRUE);
+	}
+	return((long)bn < 0 ? FALSE : TRUE);
+}
+
+static void
+vnode_pager_cluster(pager, offset, loffset, hoffset)
+	vm_pager_t	pager;
+	vm_offset_t	offset;
+	vm_offset_t	*loffset;
+	vm_offset_t	*hoffset;
+{
+	vn_pager_t vnp = (vn_pager_t)pager->pg_data;
+	vm_offset_t loff, hoff;
+
+#ifdef DEBUG
+	if (vpagerdebug & VDB_FOLLOW)
+		printf("vnode_pager_cluster(%x, %x) ", pager, offset);
+#endif
+	loff = offset;
+	if (loff >= vnp->vnp_size)
+		panic("vnode_pager_cluster: bad offset");
+	/*
+	 * XXX could use VOP_BMAP to get maxcontig value
+	 */
+	hoff = loff + MAXBSIZE;
+	if (hoff > round_page(vnp->vnp_size))
+		hoff = round_page(vnp->vnp_size);
+
+	*loffset = loff;
+	*hoffset = hoff;
+#ifdef DEBUG
+	if (vpagerdebug & VDB_FOLLOW)
+		printf("returns [%x-%x]\n", loff, hoff);
+#endif
+}
+
+/*
+ * (XXX)
+ * Lets the VM system know about a change in size for a file.
+ * If this vnode is mapped into some address space (i.e. we have a pager
+ * for it) we adjust our own internal size and flush any cached pages in
+ * the associated object that are affected by the size change.
+ *
+ * Note: this routine may be invoked as a result of a pager put
+ * operation (possibly at object termination time), so we must be careful.
+ */
+void
+vnode_pager_setsize(vp, nsize)
+	struct vnode *vp;
+	u_long nsize;
+{
+	register vn_pager_t vnp;
+	register vm_object_t object;
+	vm_pager_t pager;
+
+	/*
+	 * Not a mapped vnode
+	 */
+	if (vp == NULL || vp->v_type != VREG || vp->v_vmdata == NULL)
+		return;
+	/*
+	 * Hasn't changed size
+	 */
+	pager = (vm_pager_t)vp->v_vmdata;
+	vnp = (vn_pager_t)pager->pg_data;
+	if (nsize == vnp->vnp_size)
+		return;
+	/*
+	 * No object.
+	 * This can happen during object termination since
+	 * vm_object_page_clean is called after the object
+	 * has been removed from the hash table, and clean
+	 * may cause vnode write operations which can wind
+	 * up back here.
+	 */
+	object = vm_object_lookup(pager);
+	if (object == NULL)
+		return;
+
+#ifdef DEBUG
+	if (vpagerdebug & (VDB_FOLLOW|VDB_SIZE))
+		printf("vnode_pager_setsize: vp %x obj %x osz %d nsz %d\n",
+		       vp, object, vnp->vnp_size, nsize);
+#endif
+	/*
+	 * File has shrunk.
+	 * Toss any cached pages beyond the new EOF.
+	 */
+	if (nsize < vnp->vnp_size) {
+		vm_object_lock(object);
+		vm_object_page_remove(object,
+				      (vm_offset_t)nsize, vnp->vnp_size);
+		vm_object_unlock(object);
+	}
+	vnp->vnp_size = (vm_offset_t)nsize;
+	vm_object_deallocate(object);
+}
+
+void
+vnode_pager_umount(mp)
+	register struct mount *mp;
+{
+	register vm_pager_t pager, npager;
+	struct vnode *vp;
+
+	for (pager = vnode_pager_list.tqh_first; pager != NULL; pager = npager){
+		/*
+		 * Save the next pointer now since uncaching may
+		 * terminate the object and render pager invalid
+		 */
+		npager = pager->pg_list.tqe_next;
+		vp = ((vn_pager_t)pager->pg_data)->vnp_vp;
+		if (mp == (struct mount *)0 || vp->v_mount == mp) {
+			VOP_LOCK(vp);
+			(void) vnode_pager_uncache(vp);
+			VOP_UNLOCK(vp);
+		}
+	}
+}
+
+/*
+ * Remove vnode associated object from the object cache.
+ *
+ * XXX unlock the vnode if it is currently locked.
+ * We must do this since uncaching the object may result in its
+ * destruction which may initiate paging activity which may necessitate
+ * re-locking the vnode.
+ */
+boolean_t
+vnode_pager_uncache(vp)
+	register struct vnode *vp;
+{
+	register vm_object_t object;
+	boolean_t uncached;
+	vm_pager_t pager;
+
+	/*
+	 * Not a mapped vnode
+	 */
+	pager = (vm_pager_t)vp->v_vmdata;
+	if (pager == NULL)
+		return (TRUE);
+#ifdef DEBUG
+	if (!VOP_ISLOCKED(vp)) {
+		extern int (**nfsv2_vnodeop_p)();
+
+		if (vp->v_op != nfsv2_vnodeop_p)
+			panic("vnode_pager_uncache: vnode not locked!");
+	}
+#endif
+	/*
+	 * Must use vm_object_lookup() as it actually removes
+	 * the object from the cache list.
+	 */
+	object = vm_object_lookup(pager);
+	if (object) {
+		uncached = (object->ref_count <= 1);
+		VOP_UNLOCK(vp);
+		pager_cache(object, FALSE);
+		VOP_LOCK(vp);
+	} else
+		uncached = TRUE;
+	return(uncached);
+}
+
+static int
+vnode_pager_io(vnp, mlist, npages, sync, rw)
+	register vn_pager_t vnp;
+	vm_page_t *mlist;
+	int npages;
+	boolean_t sync;
+	enum uio_rw rw;
+{
+	struct uio auio;
+	struct iovec aiov;
+	vm_offset_t kva, foff;
+	int error, size;
+	struct proc *p = curproc;		/* XXX */
+
+	/* XXX */
+	vm_page_t m;
+	if (npages != 1)
+		panic("vnode_pager_io: cannot handle multiple pages");
+	m = *mlist;
+	/* XXX */
+
+#ifdef DEBUG
+	if (vpagerdebug & VDB_FOLLOW)
+		printf("vnode_pager_io(%x, %x, %c): vnode %x\n",
+		       vnp, m, rw == UIO_READ ? 'R' : 'W', vnp->vnp_vp);
+#endif
+	foff = m->offset + m->object->paging_offset;
+	/*
+	 * Allocate a kernel virtual address and initialize so that
+	 * we can use VOP_READ/WRITE routines.
+	 */
+	kva = vm_pager_map_pages(mlist, npages, sync);
+	if (kva == NULL)
+		return(VM_PAGER_AGAIN);
+	/*
+	 * After all of the potentially blocking operations have been
+	 * performed, we can do the size checks:
+	 *	read beyond EOF (returns error)
+	 *	short read
+	 */
+	VOP_LOCK(vnp->vnp_vp);
+	if (foff >= vnp->vnp_size) {
+		VOP_UNLOCK(vnp->vnp_vp);
+		vm_pager_unmap_pages(kva, npages);
+#ifdef DEBUG
+		if (vpagerdebug & VDB_SIZE)
+			printf("vnode_pager_io: vp %x, off %d size %d\n",
+			       vnp->vnp_vp, foff, vnp->vnp_size);
+#endif
+		return(VM_PAGER_BAD);
+	}
+	if (foff + PAGE_SIZE > vnp->vnp_size)
+		size = vnp->vnp_size - foff;
+	else
+		size = PAGE_SIZE;
+	aiov.iov_base = (caddr_t)kva;
+	aiov.iov_len = size;
+	auio.uio_iov = &aiov;
+	auio.uio_iovcnt = 1;
+	auio.uio_offset = foff;
+	auio.uio_segflg = UIO_SYSSPACE;
+	auio.uio_rw = rw;
+	auio.uio_resid = size;
+	auio.uio_procp = (struct proc *)0;
+#ifdef DEBUG
+	if (vpagerdebug & VDB_IO)
+		printf("vnode_pager_io: vp %x kva %x foff %x size %x",
+		       vnp->vnp_vp, kva, foff, size);
+#endif
+	if (rw == UIO_READ)
+		error = VOP_READ(vnp->vnp_vp, &auio, 0, p->p_ucred);
+	else
+		error = VOP_WRITE(vnp->vnp_vp, &auio, 0, p->p_ucred);
+	VOP_UNLOCK(vnp->vnp_vp);
+#ifdef DEBUG
+	if (vpagerdebug & VDB_IO) {
+		if (error || auio.uio_resid)
+			printf(" returns error %x, resid %x",
+			       error, auio.uio_resid);
+		printf("\n");
+	}
+#endif
+	if (!error) {
+		register int count = size - auio.uio_resid;
+
+		if (count == 0)
+			error = EINVAL;
+		else if (count != PAGE_SIZE && rw == UIO_READ)
+			bzero((void *)(kva + count), PAGE_SIZE - count);
+	}
+	vm_pager_unmap_pages(kva, npages);
+	return (error ? VM_PAGER_ERROR : VM_PAGER_OK);
+}
diff --git a/sys/vm/vnode_pager.h b/sys/vm/vnode_pager.h
new file mode 100644
index 0000000..95c9545
--- /dev/null
+++ b/sys/vm/vnode_pager.h
@@ -0,0 +1,59 @@
+/*
+ * Copyright (c) 1990 University of Utah.
+ * Copyright (c) 1991, 1993
+ *	The Regents of the University of California.  All rights reserved.
+ *
+ * This code is derived from software contributed to Berkeley by
+ * the Systems Programming Group of the University of Utah Computer
+ * Science Department.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. All advertising materials mentioning features or use of this software
+ *    must display the following acknowledgement:
+ *	This product includes software developed by the University of
+ *	California, Berkeley and its contributors.
+ * 4. Neither the name of the University nor the names of its contributors
+ *    may be used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ *
+ *	@(#)vnode_pager.h	8.1 (Berkeley) 6/11/93
+ */
+
+#ifndef	_VNODE_PAGER_
+#define	_VNODE_PAGER_	1
+
+/*
+ * VNODE pager private data.
+ */
+struct vnpager {
+	int		vnp_flags;	/* flags */
+	struct vnode	*vnp_vp;	/* vnode */
+	vm_size_t	vnp_size;	/* vnode current size */
+};
+typedef struct vnpager	*vn_pager_t;
+
+#define VN_PAGER_NULL	((vn_pager_t)0)
+
+#define	VNP_PAGING	0x01		/* vnode used for pageout */
+#define VNP_CACHED	0x02		/* vnode is cached */
+
+#endif	/* _VNODE_PAGER_ */