vm_object.c revision 124084
1/*
2 * Copyright (c) 1991, 1993
3 *	The Regents of the University of California.  All rights reserved.
4 *
5 * This code is derived from software contributed to Berkeley by
6 * The Mach Operating System project at Carnegie-Mellon University.
7 *
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted provided that the following conditions
10 * are met:
11 * 1. Redistributions of source code must retain the above copyright
12 *    notice, this list of conditions and the following disclaimer.
13 * 2. Redistributions in binary form must reproduce the above copyright
14 *    notice, this list of conditions and the following disclaimer in the
15 *    documentation and/or other materials provided with the distribution.
16 * 3. All advertising materials mentioning features or use of this software
17 *    must display the following acknowledgement:
18 *	This product includes software developed by the University of
19 *	California, Berkeley and its contributors.
20 * 4. Neither the name of the University nor the names of its contributors
21 *    may be used to endorse or promote products derived from this software
22 *    without specific prior written permission.
23 *
24 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
25 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
26 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
27 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
28 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
29 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
30 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
31 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
32 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
33 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
34 * SUCH DAMAGE.
35 *
36 *	from: @(#)vm_object.c	8.5 (Berkeley) 3/22/94
37 *
38 *
39 * Copyright (c) 1987, 1990 Carnegie-Mellon University.
40 * All rights reserved.
41 *
42 * Authors: Avadis Tevanian, Jr., Michael Wayne Young
43 *
44 * Permission to use, copy, modify and distribute this software and
45 * its documentation is hereby granted, provided that both the copyright
46 * notice and this permission notice appear in all copies of the
47 * software, derivative works or modified versions, and any portions
48 * thereof, and that both notices appear in supporting documentation.
49 *
50 * CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS"
51 * CONDITION.  CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND
52 * FOR ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
53 *
54 * Carnegie Mellon requests users of this software to return to
55 *
56 *  Software Distribution Coordinator  or  Software.Distribution@CS.CMU.EDU
57 *  School of Computer Science
58 *  Carnegie Mellon University
59 *  Pittsburgh PA 15213-3890
60 *
61 * any improvements or extensions that they make and grant Carnegie the
62 * rights to redistribute these changes.
63 */
64
65/*
66 *	Virtual memory object module.
67 */
68
69#include <sys/cdefs.h>
70__FBSDID("$FreeBSD: head/sys/vm/vm_object.c 124084 2004-01-02 19:57:45Z alc $");
71
72#include <sys/param.h>
73#include <sys/systm.h>
74#include <sys/lock.h>
75#include <sys/mman.h>
76#include <sys/mount.h>
77#include <sys/kernel.h>
78#include <sys/sysctl.h>
79#include <sys/mutex.h>
80#include <sys/proc.h>		/* for curproc, pageproc */
81#include <sys/socket.h>
82#include <sys/vnode.h>
83#include <sys/vmmeter.h>
84#include <sys/sx.h>
85
86#include <vm/vm.h>
87#include <vm/vm_param.h>
88#include <vm/pmap.h>
89#include <vm/vm_map.h>
90#include <vm/vm_object.h>
91#include <vm/vm_page.h>
92#include <vm/vm_pageout.h>
93#include <vm/vm_pager.h>
94#include <vm/swap_pager.h>
95#include <vm/vm_kern.h>
96#include <vm/vm_extern.h>
97#include <vm/uma.h>
98
99#define EASY_SCAN_FACTOR       8
100
101#define MSYNC_FLUSH_HARDSEQ	0x01
102#define MSYNC_FLUSH_SOFTSEQ	0x02
103
104/*
105 * msync / VM object flushing optimizations
106 */
107static int msync_flush_flags = MSYNC_FLUSH_HARDSEQ | MSYNC_FLUSH_SOFTSEQ;
108SYSCTL_INT(_vm, OID_AUTO, msync_flush_flags,
109        CTLFLAG_RW, &msync_flush_flags, 0, "");
110
111static void	vm_object_qcollapse(vm_object_t object);
112static int	vm_object_page_collect_flush(vm_object_t object, vm_page_t p, int curgeneration, int pagerflags);
113
114/*
115 *	Virtual memory objects maintain the actual data
116 *	associated with allocated virtual memory.  A given
117 *	page of memory exists within exactly one object.
118 *
119 *	An object is only deallocated when all "references"
120 *	are given up.  Only one "reference" to a given
121 *	region of an object should be writeable.
122 *
123 *	Associated with each object is a list of all resident
124 *	memory pages belonging to that object; this list is
125 *	maintained by the "vm_page" module, and locked by the object's
126 *	lock.
127 *
128 *	Each object also records a "pager" routine which is
129 *	used to retrieve (and store) pages to the proper backing
130 *	storage.  In addition, objects may be backed by other
131 *	objects from which they were virtual-copied.
132 *
133 *	The only items within the object structure which are
134 *	modified after time of creation are:
135 *		reference count		locked by object's lock
136 *		pager routine		locked by object's lock
137 *
138 */
139
140struct object_q vm_object_list;
141struct mtx vm_object_list_mtx;	/* lock for object list and count */
142
143struct vm_object kernel_object_store;
144struct vm_object kmem_object_store;
145
146static long object_collapses;
147static long object_bypasses;
148static int next_index;
149static uma_zone_t obj_zone;
150#define VM_OBJECTS_INIT 256
151
152static void vm_object_zinit(void *mem, int size);
153
154#ifdef INVARIANTS
155static void vm_object_zdtor(void *mem, int size, void *arg);
156
157static void
158vm_object_zdtor(void *mem, int size, void *arg)
159{
160	vm_object_t object;
161
162	object = (vm_object_t)mem;
163	KASSERT(TAILQ_EMPTY(&object->memq),
164	    ("object %p has resident pages",
165	    object));
166	KASSERT(object->paging_in_progress == 0,
167	    ("object %p paging_in_progress = %d",
168	    object, object->paging_in_progress));
169	KASSERT(object->resident_page_count == 0,
170	    ("object %p resident_page_count = %d",
171	    object, object->resident_page_count));
172	KASSERT(object->shadow_count == 0,
173	    ("object %p shadow_count = %d",
174	    object, object->shadow_count));
175}
176#endif
177
178static void
179vm_object_zinit(void *mem, int size)
180{
181	vm_object_t object;
182
183	object = (vm_object_t)mem;
184	bzero(&object->mtx, sizeof(object->mtx));
185	VM_OBJECT_LOCK_INIT(object);
186
187	/* These are true for any object that has been freed */
188	object->paging_in_progress = 0;
189	object->resident_page_count = 0;
190	object->shadow_count = 0;
191}
192
193void
194_vm_object_allocate(objtype_t type, vm_pindex_t size, vm_object_t object)
195{
196	int incr;
197
198	TAILQ_INIT(&object->memq);
199	LIST_INIT(&object->shadow_head);
200
201	object->root = NULL;
202	object->type = type;
203	object->size = size;
204	object->generation = 1;
205	object->ref_count = 1;
206	object->flags = 0;
207	if ((object->type == OBJT_DEFAULT) || (object->type == OBJT_SWAP))
208		object->flags = OBJ_ONEMAPPING;
209	if (size > (PQ_L2_SIZE / 3 + PQ_PRIME1))
210		incr = PQ_L2_SIZE / 3 + PQ_PRIME1;
211	else
212		incr = size;
213	do
214		object->pg_color = next_index;
215	while (!atomic_cmpset_int(&next_index, object->pg_color,
216				  (object->pg_color + incr) & PQ_L2_MASK));
217	object->handle = NULL;
218	object->backing_object = NULL;
219	object->backing_object_offset = (vm_ooffset_t) 0;
220
221	mtx_lock(&vm_object_list_mtx);
222	TAILQ_INSERT_TAIL(&vm_object_list, object, object_list);
223	mtx_unlock(&vm_object_list_mtx);
224}
225
226/*
227 *	vm_object_init:
228 *
229 *	Initialize the VM objects module.
230 */
231void
232vm_object_init(void)
233{
234	TAILQ_INIT(&vm_object_list);
235	mtx_init(&vm_object_list_mtx, "vm object_list", NULL, MTX_DEF);
236
237	VM_OBJECT_LOCK_INIT(&kernel_object_store);
238	_vm_object_allocate(OBJT_DEFAULT, OFF_TO_IDX(VM_MAX_KERNEL_ADDRESS - VM_MIN_KERNEL_ADDRESS),
239	    kernel_object);
240
241	/*
242	 * The kmem object's mutex is given a unique name, instead of
243	 * "vm object", to avoid false reports of lock-order reversal
244	 * with a system map mutex.
245	 */
246	mtx_init(VM_OBJECT_MTX(kmem_object), "kmem object", NULL, MTX_DEF);
247	_vm_object_allocate(OBJT_DEFAULT, OFF_TO_IDX(VM_MAX_KERNEL_ADDRESS - VM_MIN_KERNEL_ADDRESS),
248	    kmem_object);
249
250	obj_zone = uma_zcreate("VM OBJECT", sizeof (struct vm_object), NULL,
251#ifdef INVARIANTS
252	    vm_object_zdtor,
253#else
254	    NULL,
255#endif
256	    vm_object_zinit, NULL, UMA_ALIGN_PTR, UMA_ZONE_VM|UMA_ZONE_NOFREE);
257	uma_prealloc(obj_zone, VM_OBJECTS_INIT);
258}
259
260void
261vm_object_clear_flag(vm_object_t object, u_short bits)
262{
263
264	VM_OBJECT_LOCK_ASSERT(object, MA_OWNED);
265	object->flags &= ~bits;
266}
267
268void
269vm_object_pip_add(vm_object_t object, short i)
270{
271
272	VM_OBJECT_LOCK_ASSERT(object, MA_OWNED);
273	object->paging_in_progress += i;
274}
275
276void
277vm_object_pip_subtract(vm_object_t object, short i)
278{
279
280	VM_OBJECT_LOCK_ASSERT(object, MA_OWNED);
281	object->paging_in_progress -= i;
282}
283
284void
285vm_object_pip_wakeup(vm_object_t object)
286{
287
288	VM_OBJECT_LOCK_ASSERT(object, MA_OWNED);
289	object->paging_in_progress--;
290	if ((object->flags & OBJ_PIPWNT) && object->paging_in_progress == 0) {
291		vm_object_clear_flag(object, OBJ_PIPWNT);
292		wakeup(object);
293	}
294}
295
296void
297vm_object_pip_wakeupn(vm_object_t object, short i)
298{
299
300	VM_OBJECT_LOCK_ASSERT(object, MA_OWNED);
301	if (i)
302		object->paging_in_progress -= i;
303	if ((object->flags & OBJ_PIPWNT) && object->paging_in_progress == 0) {
304		vm_object_clear_flag(object, OBJ_PIPWNT);
305		wakeup(object);
306	}
307}
308
309void
310vm_object_pip_wait(vm_object_t object, char *waitid)
311{
312
313	VM_OBJECT_LOCK_ASSERT(object, MA_OWNED);
314	while (object->paging_in_progress) {
315		object->flags |= OBJ_PIPWNT;
316		msleep(object, VM_OBJECT_MTX(object), PVM, waitid, 0);
317	}
318}
319
320/*
321 *	vm_object_allocate_wait
322 *
323 *	Return a new object with the given size, and give the user the
324 *	option of waiting for it to complete or failing if the needed
325 *	memory isn't available.
326 */
327vm_object_t
328vm_object_allocate_wait(objtype_t type, vm_pindex_t size, int flags)
329{
330	vm_object_t result;
331
332	result = (vm_object_t) uma_zalloc(obj_zone, flags);
333
334	if (result != NULL)
335		_vm_object_allocate(type, size, result);
336
337	return (result);
338}
339
340/*
341 *	vm_object_allocate:
342 *
343 *	Returns a new object with the given size.
344 */
345vm_object_t
346vm_object_allocate(objtype_t type, vm_pindex_t size)
347{
348	return(vm_object_allocate_wait(type, size, M_WAITOK));
349}
350
351
352/*
353 *	vm_object_reference:
354 *
355 *	Gets another reference to the given object.  Note: OBJ_DEAD
356 *	objects can be referenced during final cleaning.
357 */
358void
359vm_object_reference(vm_object_t object)
360{
361	struct vnode *vp;
362	int flags;
363
364	if (object == NULL)
365		return;
366	VM_OBJECT_LOCK(object);
367	object->ref_count++;
368	if (object->type == OBJT_VNODE) {
369		vp = object->handle;
370		VI_LOCK(vp);
371		VM_OBJECT_UNLOCK(object);
372		for (flags = LK_INTERLOCK; vget(vp, flags, curthread);
373		     flags = 0)
374			printf("vm_object_reference: delay in vget\n");
375	} else
376		VM_OBJECT_UNLOCK(object);
377}
378
379/*
380 *	vm_object_reference_locked:
381 *
382 *	Gets another reference to the given object.
383 *
384 *	The object must be locked.
385 */
386void
387vm_object_reference_locked(vm_object_t object)
388{
389	struct vnode *vp;
390
391	VM_OBJECT_LOCK_ASSERT(object, MA_OWNED);
392	KASSERT((object->flags & OBJ_DEAD) == 0,
393	    ("vm_object_reference_locked: dead object referenced"));
394	object->ref_count++;
395	if (object->type == OBJT_VNODE) {
396		vp = object->handle;
397		vref(vp);
398	}
399}
400
401/*
402 * Handle deallocating an object of type OBJT_VNODE.
403 */
404void
405vm_object_vndeallocate(vm_object_t object)
406{
407	struct vnode *vp = (struct vnode *) object->handle;
408
409	GIANT_REQUIRED;
410	VM_OBJECT_LOCK_ASSERT(object, MA_OWNED);
411	KASSERT(object->type == OBJT_VNODE,
412	    ("vm_object_vndeallocate: not a vnode object"));
413	KASSERT(vp != NULL, ("vm_object_vndeallocate: missing vp"));
414#ifdef INVARIANTS
415	if (object->ref_count == 0) {
416		vprint("vm_object_vndeallocate", vp);
417		panic("vm_object_vndeallocate: bad object reference count");
418	}
419#endif
420
421	object->ref_count--;
422	if (object->ref_count == 0) {
423		mp_fixme("Unlocked vflag access.");
424		vp->v_vflag &= ~VV_TEXT;
425	}
426	VM_OBJECT_UNLOCK(object);
427	/*
428	 * vrele may need a vop lock
429	 */
430	vrele(vp);
431}
432
433/*
434 *	vm_object_deallocate:
435 *
436 *	Release a reference to the specified object,
437 *	gained either through a vm_object_allocate
438 *	or a vm_object_reference call.  When all references
439 *	are gone, storage associated with this object
440 *	may be relinquished.
441 *
442 *	No object may be locked.
443 */
444void
445vm_object_deallocate(vm_object_t object)
446{
447	vm_object_t temp;
448
449	if (object != kmem_object)
450		mtx_lock(&Giant);
451	while (object != NULL) {
452		VM_OBJECT_LOCK(object);
453		if (object->type == OBJT_VNODE) {
454			vm_object_vndeallocate(object);
455			goto done;
456		}
457
458		KASSERT(object->ref_count != 0,
459			("vm_object_deallocate: object deallocated too many times: %d", object->type));
460
461		/*
462		 * If the reference count goes to 0 we start calling
463		 * vm_object_terminate() on the object chain.
464		 * A ref count of 1 may be a special case depending on the
465		 * shadow count being 0 or 1.
466		 */
467		object->ref_count--;
468		if (object->ref_count > 1) {
469			VM_OBJECT_UNLOCK(object);
470			goto done;
471		} else if (object->ref_count == 1) {
472			if (object->shadow_count == 0) {
473				vm_object_set_flag(object, OBJ_ONEMAPPING);
474			} else if ((object->shadow_count == 1) &&
475			    (object->handle == NULL) &&
476			    (object->type == OBJT_DEFAULT ||
477			     object->type == OBJT_SWAP)) {
478				vm_object_t robject;
479
480				robject = LIST_FIRST(&object->shadow_head);
481				KASSERT(robject != NULL,
482				    ("vm_object_deallocate: ref_count: %d, shadow_count: %d",
483					 object->ref_count,
484					 object->shadow_count));
485				if (!VM_OBJECT_TRYLOCK(robject)) {
486					/*
487					 * Avoid a potential deadlock.
488					 */
489					object->ref_count++;
490					VM_OBJECT_UNLOCK(object);
491					continue;
492				}
493				if ((robject->handle == NULL) &&
494				    (robject->type == OBJT_DEFAULT ||
495				     robject->type == OBJT_SWAP)) {
496
497					robject->ref_count++;
498retry:
499					if (robject->paging_in_progress) {
500						VM_OBJECT_UNLOCK(object);
501						vm_object_pip_wait(robject,
502						    "objde1");
503						VM_OBJECT_LOCK(object);
504						goto retry;
505					} else if (object->paging_in_progress) {
506						VM_OBJECT_UNLOCK(robject);
507						object->flags |= OBJ_PIPWNT;
508						msleep(object,
509						    VM_OBJECT_MTX(object),
510						    PDROP | PVM, "objde2", 0);
511						VM_OBJECT_LOCK(robject);
512						VM_OBJECT_LOCK(object);
513						goto retry;
514					}
515					VM_OBJECT_UNLOCK(object);
516					if (robject->ref_count == 1) {
517						robject->ref_count--;
518						object = robject;
519						goto doterm;
520					}
521					object = robject;
522					vm_object_collapse(object);
523					VM_OBJECT_UNLOCK(object);
524					continue;
525				}
526				VM_OBJECT_UNLOCK(robject);
527			}
528			VM_OBJECT_UNLOCK(object);
529			goto done;
530		}
531doterm:
532		temp = object->backing_object;
533		if (temp != NULL) {
534			VM_OBJECT_LOCK(temp);
535			LIST_REMOVE(object, shadow_list);
536			temp->shadow_count--;
537			temp->generation++;
538			VM_OBJECT_UNLOCK(temp);
539			object->backing_object = NULL;
540		}
541		/*
542		 * Don't double-terminate, we could be in a termination
543		 * recursion due to the terminate having to sync data
544		 * to disk.
545		 */
546		if ((object->flags & OBJ_DEAD) == 0)
547			vm_object_terminate(object);
548		else
549			VM_OBJECT_UNLOCK(object);
550		object = temp;
551	}
552done:
553	if (object != kmem_object)
554		mtx_unlock(&Giant);
555}
556
557/*
558 *	vm_object_terminate actually destroys the specified object, freeing
559 *	up all previously used resources.
560 *
561 *	The object must be locked.
562 *	This routine may block.
563 */
564void
565vm_object_terminate(vm_object_t object)
566{
567	vm_page_t p;
568	int s;
569
570	VM_OBJECT_LOCK_ASSERT(object, MA_OWNED);
571
572	/*
573	 * Make sure no one uses us.
574	 */
575	vm_object_set_flag(object, OBJ_DEAD);
576
577	/*
578	 * wait for the pageout daemon to be done with the object
579	 */
580	vm_object_pip_wait(object, "objtrm");
581
582	KASSERT(!object->paging_in_progress,
583		("vm_object_terminate: pageout in progress"));
584
585	/*
586	 * Clean and free the pages, as appropriate. All references to the
587	 * object are gone, so we don't need to lock it.
588	 */
589	if (object->type == OBJT_VNODE) {
590		struct vnode *vp = (struct vnode *)object->handle;
591
592		/*
593		 * Clean pages and flush buffers.
594		 */
595		vm_object_page_clean(object, 0, 0, OBJPC_SYNC);
596		VM_OBJECT_UNLOCK(object);
597
598		vinvalbuf(vp, V_SAVE, NOCRED, NULL, 0, 0);
599
600		VM_OBJECT_LOCK(object);
601	}
602
603	KASSERT(object->ref_count == 0,
604		("vm_object_terminate: object with references, ref_count=%d",
605		object->ref_count));
606
607	/*
608	 * Now free any remaining pages. For internal objects, this also
609	 * removes them from paging queues. Don't free wired pages, just
610	 * remove them from the object.
611	 */
612	s = splvm();
613	vm_page_lock_queues();
614	while ((p = TAILQ_FIRST(&object->memq)) != NULL) {
615		KASSERT(!p->busy && (p->flags & PG_BUSY) == 0,
616			("vm_object_terminate: freeing busy page %p "
617			"p->busy = %d, p->flags %x\n", p, p->busy, p->flags));
618		if (p->wire_count == 0) {
619			vm_page_busy(p);
620			vm_page_free(p);
621			cnt.v_pfree++;
622		} else {
623			vm_page_busy(p);
624			vm_page_remove(p);
625		}
626	}
627	vm_page_unlock_queues();
628	splx(s);
629
630	/*
631	 * Let the pager know object is dead.
632	 */
633	vm_pager_deallocate(object);
634	VM_OBJECT_UNLOCK(object);
635
636	/*
637	 * Remove the object from the global object list.
638	 */
639	mtx_lock(&vm_object_list_mtx);
640	TAILQ_REMOVE(&vm_object_list, object, object_list);
641	mtx_unlock(&vm_object_list_mtx);
642
643	wakeup(object);
644
645	/*
646	 * Free the space for the object.
647	 */
648	uma_zfree(obj_zone, object);
649}
650
651/*
652 *	vm_object_page_clean
653 *
654 *	Clean all dirty pages in the specified range of object.  Leaves page
655 * 	on whatever queue it is currently on.   If NOSYNC is set then do not
656 *	write out pages with PG_NOSYNC set (originally comes from MAP_NOSYNC),
657 *	leaving the object dirty.
658 *
659 *	When stuffing pages asynchronously, allow clustering.  XXX we need a
660 *	synchronous clustering mode implementation.
661 *
662 *	Odd semantics: if start == end, we clean everything.
663 *
664 *	The object must be locked.
665 */
666void
667vm_object_page_clean(vm_object_t object, vm_pindex_t start, vm_pindex_t end, int flags)
668{
669	vm_page_t p, np;
670	vm_pindex_t tstart, tend;
671	vm_pindex_t pi;
672	int clearobjflags;
673	int pagerflags;
674	int curgeneration;
675
676	GIANT_REQUIRED;
677	VM_OBJECT_LOCK_ASSERT(object, MA_OWNED);
678	if (object->type != OBJT_VNODE ||
679		(object->flags & OBJ_MIGHTBEDIRTY) == 0)
680		return;
681
682	pagerflags = (flags & (OBJPC_SYNC | OBJPC_INVAL)) ? VM_PAGER_PUT_SYNC : VM_PAGER_CLUSTER_OK;
683	pagerflags |= (flags & OBJPC_INVAL) ? VM_PAGER_PUT_INVAL : 0;
684
685	vm_object_set_flag(object, OBJ_CLEANING);
686
687	tstart = start;
688	if (end == 0) {
689		tend = object->size;
690	} else {
691		tend = end;
692	}
693
694	vm_page_lock_queues();
695	/*
696	 * If the caller is smart and only msync()s a range he knows is
697	 * dirty, we may be able to avoid an object scan.  This results in
698	 * a phenominal improvement in performance.  We cannot do this
699	 * as a matter of course because the object may be huge - e.g.
700	 * the size might be in the gigabytes or terrabytes.
701	 */
702	if (msync_flush_flags & MSYNC_FLUSH_HARDSEQ) {
703		vm_pindex_t tscan;
704		int scanlimit;
705		int scanreset;
706
707		scanreset = object->resident_page_count / EASY_SCAN_FACTOR;
708		if (scanreset < 16)
709			scanreset = 16;
710		pagerflags |= VM_PAGER_IGNORE_CLEANCHK;
711
712		scanlimit = scanreset;
713		tscan = tstart;
714		while (tscan < tend) {
715			curgeneration = object->generation;
716			p = vm_page_lookup(object, tscan);
717			if (p == NULL || p->valid == 0 ||
718			    (p->queue - p->pc) == PQ_CACHE) {
719				if (--scanlimit == 0)
720					break;
721				++tscan;
722				continue;
723			}
724			vm_page_test_dirty(p);
725			if ((p->dirty & p->valid) == 0) {
726				if (--scanlimit == 0)
727					break;
728				++tscan;
729				continue;
730			}
731			/*
732			 * If we have been asked to skip nosync pages and
733			 * this is a nosync page, we can't continue.
734			 */
735			if ((flags & OBJPC_NOSYNC) && (p->flags & PG_NOSYNC)) {
736				if (--scanlimit == 0)
737					break;
738				++tscan;
739				continue;
740			}
741			scanlimit = scanreset;
742
743			/*
744			 * This returns 0 if it was unable to busy the first
745			 * page (i.e. had to sleep).
746			 */
747			tscan += vm_object_page_collect_flush(object, p, curgeneration, pagerflags);
748		}
749
750		/*
751		 * If everything was dirty and we flushed it successfully,
752		 * and the requested range is not the entire object, we
753		 * don't have to mess with CLEANCHK or MIGHTBEDIRTY and can
754		 * return immediately.
755		 */
756		if (tscan >= tend && (tstart || tend < object->size)) {
757			vm_page_unlock_queues();
758			vm_object_clear_flag(object, OBJ_CLEANING);
759			return;
760		}
761		pagerflags &= ~VM_PAGER_IGNORE_CLEANCHK;
762	}
763
764	/*
765	 * Generally set CLEANCHK interlock and make the page read-only so
766	 * we can then clear the object flags.
767	 *
768	 * However, if this is a nosync mmap then the object is likely to
769	 * stay dirty so do not mess with the page and do not clear the
770	 * object flags.
771	 */
772	clearobjflags = 1;
773	TAILQ_FOREACH(p, &object->memq, listq) {
774		vm_page_flag_set(p, PG_CLEANCHK);
775		if ((flags & OBJPC_NOSYNC) && (p->flags & PG_NOSYNC))
776			clearobjflags = 0;
777		else
778			pmap_page_protect(p, VM_PROT_READ);
779	}
780
781	if (clearobjflags && (tstart == 0) && (tend == object->size)) {
782		struct vnode *vp;
783
784		vm_object_clear_flag(object, OBJ_WRITEABLE|OBJ_MIGHTBEDIRTY);
785		if (object->type == OBJT_VNODE &&
786		    (vp = (struct vnode *)object->handle) != NULL) {
787			VI_LOCK(vp);
788			if (vp->v_iflag & VI_OBJDIRTY)
789				vp->v_iflag &= ~VI_OBJDIRTY;
790			VI_UNLOCK(vp);
791		}
792	}
793
794rescan:
795	curgeneration = object->generation;
796
797	for (p = TAILQ_FIRST(&object->memq); p; p = np) {
798		int n;
799
800		np = TAILQ_NEXT(p, listq);
801
802again:
803		pi = p->pindex;
804		if (((p->flags & PG_CLEANCHK) == 0) ||
805			(pi < tstart) || (pi >= tend) ||
806			(p->valid == 0) ||
807			((p->queue - p->pc) == PQ_CACHE)) {
808			vm_page_flag_clear(p, PG_CLEANCHK);
809			continue;
810		}
811
812		vm_page_test_dirty(p);
813		if ((p->dirty & p->valid) == 0) {
814			vm_page_flag_clear(p, PG_CLEANCHK);
815			continue;
816		}
817
818		/*
819		 * If we have been asked to skip nosync pages and this is a
820		 * nosync page, skip it.  Note that the object flags were
821		 * not cleared in this case so we do not have to set them.
822		 */
823		if ((flags & OBJPC_NOSYNC) && (p->flags & PG_NOSYNC)) {
824			vm_page_flag_clear(p, PG_CLEANCHK);
825			continue;
826		}
827
828		n = vm_object_page_collect_flush(object, p,
829			curgeneration, pagerflags);
830		if (n == 0)
831			goto rescan;
832
833		if (object->generation != curgeneration)
834			goto rescan;
835
836		/*
837		 * Try to optimize the next page.  If we can't we pick up
838		 * our (random) scan where we left off.
839		 */
840		if (msync_flush_flags & MSYNC_FLUSH_SOFTSEQ) {
841			if ((p = vm_page_lookup(object, pi + n)) != NULL)
842				goto again;
843		}
844	}
845	vm_page_unlock_queues();
846#if 0
847	VOP_FSYNC(vp, NULL, (pagerflags & VM_PAGER_PUT_SYNC)?MNT_WAIT:0, curproc);
848#endif
849
850	vm_object_clear_flag(object, OBJ_CLEANING);
851	return;
852}
853
854static int
855vm_object_page_collect_flush(vm_object_t object, vm_page_t p, int curgeneration, int pagerflags)
856{
857	int runlen;
858	int s;
859	int maxf;
860	int chkb;
861	int maxb;
862	int i;
863	vm_pindex_t pi;
864	vm_page_t maf[vm_pageout_page_count];
865	vm_page_t mab[vm_pageout_page_count];
866	vm_page_t ma[vm_pageout_page_count];
867
868	s = splvm();
869	mtx_assert(&vm_page_queue_mtx, MA_OWNED);
870	pi = p->pindex;
871	while (vm_page_sleep_if_busy(p, TRUE, "vpcwai")) {
872		vm_page_lock_queues();
873		if (object->generation != curgeneration) {
874			splx(s);
875			return(0);
876		}
877	}
878	maxf = 0;
879	for(i = 1; i < vm_pageout_page_count; i++) {
880		vm_page_t tp;
881
882		if ((tp = vm_page_lookup(object, pi + i)) != NULL) {
883			if ((tp->flags & PG_BUSY) ||
884				((pagerflags & VM_PAGER_IGNORE_CLEANCHK) == 0 &&
885				 (tp->flags & PG_CLEANCHK) == 0) ||
886				(tp->busy != 0))
887				break;
888			if((tp->queue - tp->pc) == PQ_CACHE) {
889				vm_page_flag_clear(tp, PG_CLEANCHK);
890				break;
891			}
892			vm_page_test_dirty(tp);
893			if ((tp->dirty & tp->valid) == 0) {
894				vm_page_flag_clear(tp, PG_CLEANCHK);
895				break;
896			}
897			maf[ i - 1 ] = tp;
898			maxf++;
899			continue;
900		}
901		break;
902	}
903
904	maxb = 0;
905	chkb = vm_pageout_page_count -  maxf;
906	if (chkb) {
907		for(i = 1; i < chkb;i++) {
908			vm_page_t tp;
909
910			if ((tp = vm_page_lookup(object, pi - i)) != NULL) {
911				if ((tp->flags & PG_BUSY) ||
912					((pagerflags & VM_PAGER_IGNORE_CLEANCHK) == 0 &&
913					 (tp->flags & PG_CLEANCHK) == 0) ||
914					(tp->busy != 0))
915					break;
916				if ((tp->queue - tp->pc) == PQ_CACHE) {
917					vm_page_flag_clear(tp, PG_CLEANCHK);
918					break;
919				}
920				vm_page_test_dirty(tp);
921				if ((tp->dirty & tp->valid) == 0) {
922					vm_page_flag_clear(tp, PG_CLEANCHK);
923					break;
924				}
925				mab[ i - 1 ] = tp;
926				maxb++;
927				continue;
928			}
929			break;
930		}
931	}
932
933	for(i = 0; i < maxb; i++) {
934		int index = (maxb - i) - 1;
935		ma[index] = mab[i];
936		vm_page_flag_clear(ma[index], PG_CLEANCHK);
937	}
938	vm_page_flag_clear(p, PG_CLEANCHK);
939	ma[maxb] = p;
940	for(i = 0; i < maxf; i++) {
941		int index = (maxb + i) + 1;
942		ma[index] = maf[i];
943		vm_page_flag_clear(ma[index], PG_CLEANCHK);
944	}
945	runlen = maxb + maxf + 1;
946
947	splx(s);
948	vm_pageout_flush(ma, runlen, pagerflags);
949	for (i = 0; i < runlen; i++) {
950		if (ma[i]->valid & ma[i]->dirty) {
951			pmap_page_protect(ma[i], VM_PROT_READ);
952			vm_page_flag_set(ma[i], PG_CLEANCHK);
953
954			/*
955			 * maxf will end up being the actual number of pages
956			 * we wrote out contiguously, non-inclusive of the
957			 * first page.  We do not count look-behind pages.
958			 */
959			if (i >= maxb + 1 && (maxf > i - maxb - 1))
960				maxf = i - maxb - 1;
961		}
962	}
963	return(maxf + 1);
964}
965
966/*
967 * Note that there is absolutely no sense in writing out
968 * anonymous objects, so we track down the vnode object
969 * to write out.
970 * We invalidate (remove) all pages from the address space
971 * for semantic correctness.
972 *
973 * Note: certain anonymous maps, such as MAP_NOSYNC maps,
974 * may start out with a NULL object.
975 */
976void
977vm_object_sync(vm_object_t object, vm_ooffset_t offset, vm_size_t size,
978    boolean_t syncio, boolean_t invalidate)
979{
980	vm_object_t backing_object;
981	struct vnode *vp;
982	int flags;
983
984	if (object == NULL)
985		return;
986	VM_OBJECT_LOCK(object);
987	while ((backing_object = object->backing_object) != NULL) {
988		VM_OBJECT_LOCK(backing_object);
989		VM_OBJECT_UNLOCK(object);
990		object = backing_object;
991		offset += object->backing_object_offset;
992		if (object->size < OFF_TO_IDX(offset + size))
993			size = IDX_TO_OFF(object->size) - offset;
994	}
995	/*
996	 * Flush pages if writing is allowed, invalidate them
997	 * if invalidation requested.  Pages undergoing I/O
998	 * will be ignored by vm_object_page_remove().
999	 *
1000	 * We cannot lock the vnode and then wait for paging
1001	 * to complete without deadlocking against vm_fault.
1002	 * Instead we simply call vm_object_page_remove() and
1003	 * allow it to block internally on a page-by-page
1004	 * basis when it encounters pages undergoing async
1005	 * I/O.
1006	 */
1007	if (object->type == OBJT_VNODE &&
1008	    (object->flags & OBJ_MIGHTBEDIRTY) != 0) {
1009		vp = object->handle;
1010		VM_OBJECT_UNLOCK(object);
1011		mtx_lock(&Giant);
1012		vn_lock(vp, LK_EXCLUSIVE | LK_RETRY, curthread);
1013		flags = (syncio || invalidate) ? OBJPC_SYNC : 0;
1014		flags |= invalidate ? OBJPC_INVAL : 0;
1015		VM_OBJECT_LOCK(object);
1016		vm_object_page_clean(object,
1017		    OFF_TO_IDX(offset),
1018		    OFF_TO_IDX(offset + size + PAGE_MASK),
1019		    flags);
1020		VM_OBJECT_UNLOCK(object);
1021		VOP_UNLOCK(vp, 0, curthread);
1022		mtx_unlock(&Giant);
1023		VM_OBJECT_LOCK(object);
1024	}
1025	if ((object->type == OBJT_VNODE ||
1026	     object->type == OBJT_DEVICE) && invalidate) {
1027		vm_object_page_remove(object,
1028		    OFF_TO_IDX(offset),
1029		    OFF_TO_IDX(offset + size + PAGE_MASK),
1030		    FALSE);
1031	}
1032	VM_OBJECT_UNLOCK(object);
1033}
1034
1035/*
1036 *	vm_object_madvise:
1037 *
1038 *	Implements the madvise function at the object/page level.
1039 *
1040 *	MADV_WILLNEED	(any object)
1041 *
1042 *	    Activate the specified pages if they are resident.
1043 *
1044 *	MADV_DONTNEED	(any object)
1045 *
1046 *	    Deactivate the specified pages if they are resident.
1047 *
1048 *	MADV_FREE	(OBJT_DEFAULT/OBJT_SWAP objects,
1049 *			 OBJ_ONEMAPPING only)
1050 *
1051 *	    Deactivate and clean the specified pages if they are
1052 *	    resident.  This permits the process to reuse the pages
1053 *	    without faulting or the kernel to reclaim the pages
1054 *	    without I/O.
1055 */
1056void
1057vm_object_madvise(vm_object_t object, vm_pindex_t pindex, int count, int advise)
1058{
1059	vm_pindex_t end, tpindex;
1060	vm_object_t backing_object, tobject;
1061	vm_page_t m;
1062
1063	if (object == NULL)
1064		return;
1065	end = pindex + count;
1066	/*
1067	 * Locate and adjust resident pages
1068	 */
1069	for (; pindex < end; pindex += 1) {
1070relookup:
1071		tobject = object;
1072		tpindex = pindex;
1073		VM_OBJECT_LOCK(tobject);
1074shadowlookup:
1075		/*
1076		 * MADV_FREE only operates on OBJT_DEFAULT or OBJT_SWAP pages
1077		 * and those pages must be OBJ_ONEMAPPING.
1078		 */
1079		if (advise == MADV_FREE) {
1080			if ((tobject->type != OBJT_DEFAULT &&
1081			     tobject->type != OBJT_SWAP) ||
1082			    (tobject->flags & OBJ_ONEMAPPING) == 0) {
1083				goto unlock_tobject;
1084			}
1085		}
1086		m = vm_page_lookup(tobject, tpindex);
1087		if (m == NULL) {
1088			/*
1089			 * There may be swap even if there is no backing page
1090			 */
1091			if (advise == MADV_FREE && tobject->type == OBJT_SWAP)
1092				swap_pager_freespace(tobject, tpindex, 1);
1093			/*
1094			 * next object
1095			 */
1096			backing_object = tobject->backing_object;
1097			if (backing_object == NULL)
1098				goto unlock_tobject;
1099			VM_OBJECT_LOCK(backing_object);
1100			VM_OBJECT_UNLOCK(tobject);
1101			tobject = backing_object;
1102			tpindex += OFF_TO_IDX(tobject->backing_object_offset);
1103			goto shadowlookup;
1104		}
1105		/*
1106		 * If the page is busy or not in a normal active state,
1107		 * we skip it.  If the page is not managed there are no
1108		 * page queues to mess with.  Things can break if we mess
1109		 * with pages in any of the below states.
1110		 */
1111		vm_page_lock_queues();
1112		if (m->hold_count ||
1113		    m->wire_count ||
1114		    (m->flags & PG_UNMANAGED) ||
1115		    m->valid != VM_PAGE_BITS_ALL) {
1116			vm_page_unlock_queues();
1117			goto unlock_tobject;
1118		}
1119 		if (vm_page_sleep_if_busy(m, TRUE, "madvpo")) {
1120			VM_OBJECT_UNLOCK(tobject);
1121  			goto relookup;
1122		}
1123		if (advise == MADV_WILLNEED) {
1124			vm_page_activate(m);
1125		} else if (advise == MADV_DONTNEED) {
1126			vm_page_dontneed(m);
1127		} else if (advise == MADV_FREE) {
1128			/*
1129			 * Mark the page clean.  This will allow the page
1130			 * to be freed up by the system.  However, such pages
1131			 * are often reused quickly by malloc()/free()
1132			 * so we do not do anything that would cause
1133			 * a page fault if we can help it.
1134			 *
1135			 * Specifically, we do not try to actually free
1136			 * the page now nor do we try to put it in the
1137			 * cache (which would cause a page fault on reuse).
1138			 *
1139			 * But we do make the page is freeable as we
1140			 * can without actually taking the step of unmapping
1141			 * it.
1142			 */
1143			pmap_clear_modify(m);
1144			m->dirty = 0;
1145			m->act_count = 0;
1146			vm_page_dontneed(m);
1147		}
1148		vm_page_unlock_queues();
1149		if (advise == MADV_FREE && tobject->type == OBJT_SWAP)
1150			swap_pager_freespace(tobject, tpindex, 1);
1151unlock_tobject:
1152		VM_OBJECT_UNLOCK(tobject);
1153	}
1154}
1155
1156/*
1157 *	vm_object_shadow:
1158 *
1159 *	Create a new object which is backed by the
1160 *	specified existing object range.  The source
1161 *	object reference is deallocated.
1162 *
1163 *	The new object and offset into that object
1164 *	are returned in the source parameters.
1165 */
1166void
1167vm_object_shadow(
1168	vm_object_t *object,	/* IN/OUT */
1169	vm_ooffset_t *offset,	/* IN/OUT */
1170	vm_size_t length)
1171{
1172	vm_object_t source;
1173	vm_object_t result;
1174
1175	source = *object;
1176
1177	/*
1178	 * Don't create the new object if the old object isn't shared.
1179	 */
1180	if (source != NULL) {
1181		VM_OBJECT_LOCK(source);
1182		if (source->ref_count == 1 &&
1183		    source->handle == NULL &&
1184		    (source->type == OBJT_DEFAULT ||
1185		     source->type == OBJT_SWAP)) {
1186			VM_OBJECT_UNLOCK(source);
1187			return;
1188		}
1189		VM_OBJECT_UNLOCK(source);
1190	}
1191
1192	/*
1193	 * Allocate a new object with the given length.
1194	 */
1195	result = vm_object_allocate(OBJT_DEFAULT, length);
1196
1197	/*
1198	 * The new object shadows the source object, adding a reference to it.
1199	 * Our caller changes his reference to point to the new object,
1200	 * removing a reference to the source object.  Net result: no change
1201	 * of reference count.
1202	 *
1203	 * Try to optimize the result object's page color when shadowing
1204	 * in order to maintain page coloring consistency in the combined
1205	 * shadowed object.
1206	 */
1207	result->backing_object = source;
1208	if (source != NULL) {
1209		VM_OBJECT_LOCK(source);
1210		LIST_INSERT_HEAD(&source->shadow_head, result, shadow_list);
1211		source->shadow_count++;
1212		source->generation++;
1213		if (length < source->size)
1214			length = source->size;
1215		if (length > PQ_L2_SIZE / 3 + PQ_PRIME1 ||
1216		    source->generation > 1)
1217			length = PQ_L2_SIZE / 3 + PQ_PRIME1;
1218		result->pg_color = (source->pg_color +
1219		    length * source->generation) & PQ_L2_MASK;
1220		VM_OBJECT_UNLOCK(source);
1221		next_index = (result->pg_color + PQ_L2_SIZE / 3 + PQ_PRIME1) &
1222		    PQ_L2_MASK;
1223	}
1224
1225	/*
1226	 * Store the offset into the source object, and fix up the offset into
1227	 * the new object.
1228	 */
1229	result->backing_object_offset = *offset;
1230
1231	/*
1232	 * Return the new things
1233	 */
1234	*offset = 0;
1235	*object = result;
1236}
1237
1238/*
1239 *	vm_object_split:
1240 *
1241 * Split the pages in a map entry into a new object.  This affords
1242 * easier removal of unused pages, and keeps object inheritance from
1243 * being a negative impact on memory usage.
1244 */
1245void
1246vm_object_split(vm_map_entry_t entry)
1247{
1248	vm_page_t m;
1249	vm_object_t orig_object, new_object, source;
1250	vm_pindex_t offidxstart, offidxend;
1251	vm_size_t idx, size;
1252
1253	orig_object = entry->object.vm_object;
1254	if (orig_object->type != OBJT_DEFAULT && orig_object->type != OBJT_SWAP)
1255		return;
1256	if (orig_object->ref_count <= 1)
1257		return;
1258	VM_OBJECT_UNLOCK(orig_object);
1259
1260	offidxstart = OFF_TO_IDX(entry->offset);
1261	offidxend = offidxstart + OFF_TO_IDX(entry->end - entry->start);
1262	size = offidxend - offidxstart;
1263
1264	/*
1265	 * If swap_pager_copy() is later called, it will convert new_object
1266	 * into a swap object.
1267	 */
1268	new_object = vm_object_allocate(OBJT_DEFAULT, size);
1269
1270	VM_OBJECT_LOCK(new_object);
1271	VM_OBJECT_LOCK(orig_object);
1272	source = orig_object->backing_object;
1273	if (source != NULL) {
1274		VM_OBJECT_LOCK(source);
1275		LIST_INSERT_HEAD(&source->shadow_head,
1276				  new_object, shadow_list);
1277		source->shadow_count++;
1278		source->generation++;
1279		vm_object_reference_locked(source);	/* for new_object */
1280		vm_object_clear_flag(source, OBJ_ONEMAPPING);
1281		VM_OBJECT_UNLOCK(source);
1282		new_object->backing_object_offset =
1283			orig_object->backing_object_offset + entry->offset;
1284		new_object->backing_object = source;
1285	}
1286	for (idx = 0; idx < size; idx++) {
1287	retry:
1288		m = vm_page_lookup(orig_object, offidxstart + idx);
1289		if (m == NULL)
1290			continue;
1291
1292		/*
1293		 * We must wait for pending I/O to complete before we can
1294		 * rename the page.
1295		 *
1296		 * We do not have to VM_PROT_NONE the page as mappings should
1297		 * not be changed by this operation.
1298		 */
1299		vm_page_lock_queues();
1300		if ((m->flags & PG_BUSY) || m->busy) {
1301			vm_page_flag_set(m, PG_WANTED | PG_REFERENCED);
1302			VM_OBJECT_UNLOCK(orig_object);
1303			VM_OBJECT_UNLOCK(new_object);
1304			msleep(m, &vm_page_queue_mtx, PDROP | PVM, "spltwt", 0);
1305			VM_OBJECT_LOCK(new_object);
1306			VM_OBJECT_LOCK(orig_object);
1307			goto retry;
1308		}
1309		vm_page_busy(m);
1310		vm_page_rename(m, new_object, idx);
1311		/* page automatically made dirty by rename and cache handled */
1312		vm_page_busy(m);
1313		vm_page_unlock_queues();
1314	}
1315	if (orig_object->type == OBJT_SWAP) {
1316		/*
1317		 * swap_pager_copy() can sleep, in which case the orig_object's
1318		 * and new_object's locks are released and reacquired.
1319		 */
1320		swap_pager_copy(orig_object, new_object, offidxstart, 0);
1321	}
1322	VM_OBJECT_UNLOCK(orig_object);
1323	vm_page_lock_queues();
1324	TAILQ_FOREACH(m, &new_object->memq, listq)
1325		vm_page_wakeup(m);
1326	vm_page_unlock_queues();
1327	VM_OBJECT_UNLOCK(new_object);
1328	entry->object.vm_object = new_object;
1329	entry->offset = 0LL;
1330	vm_object_deallocate(orig_object);
1331	VM_OBJECT_LOCK(new_object);
1332}
1333
1334#define	OBSC_TEST_ALL_SHADOWED	0x0001
1335#define	OBSC_COLLAPSE_NOWAIT	0x0002
1336#define	OBSC_COLLAPSE_WAIT	0x0004
1337
1338static int
1339vm_object_backing_scan(vm_object_t object, int op)
1340{
1341	int s;
1342	int r = 1;
1343	vm_page_t p;
1344	vm_object_t backing_object;
1345	vm_pindex_t backing_offset_index;
1346
1347	s = splvm();
1348	VM_OBJECT_LOCK_ASSERT(object, MA_OWNED);
1349	VM_OBJECT_LOCK_ASSERT(object->backing_object, MA_OWNED);
1350
1351	backing_object = object->backing_object;
1352	backing_offset_index = OFF_TO_IDX(object->backing_object_offset);
1353
1354	/*
1355	 * Initial conditions
1356	 */
1357	if (op & OBSC_TEST_ALL_SHADOWED) {
1358		/*
1359		 * We do not want to have to test for the existence of
1360		 * swap pages in the backing object.  XXX but with the
1361		 * new swapper this would be pretty easy to do.
1362		 *
1363		 * XXX what about anonymous MAP_SHARED memory that hasn't
1364		 * been ZFOD faulted yet?  If we do not test for this, the
1365		 * shadow test may succeed! XXX
1366		 */
1367		if (backing_object->type != OBJT_DEFAULT) {
1368			splx(s);
1369			return (0);
1370		}
1371	}
1372	if (op & OBSC_COLLAPSE_WAIT) {
1373		vm_object_set_flag(backing_object, OBJ_DEAD);
1374	}
1375
1376	/*
1377	 * Our scan
1378	 */
1379	p = TAILQ_FIRST(&backing_object->memq);
1380	while (p) {
1381		vm_page_t next = TAILQ_NEXT(p, listq);
1382		vm_pindex_t new_pindex = p->pindex - backing_offset_index;
1383
1384		if (op & OBSC_TEST_ALL_SHADOWED) {
1385			vm_page_t pp;
1386
1387			/*
1388			 * Ignore pages outside the parent object's range
1389			 * and outside the parent object's mapping of the
1390			 * backing object.
1391			 *
1392			 * note that we do not busy the backing object's
1393			 * page.
1394			 */
1395			if (
1396			    p->pindex < backing_offset_index ||
1397			    new_pindex >= object->size
1398			) {
1399				p = next;
1400				continue;
1401			}
1402
1403			/*
1404			 * See if the parent has the page or if the parent's
1405			 * object pager has the page.  If the parent has the
1406			 * page but the page is not valid, the parent's
1407			 * object pager must have the page.
1408			 *
1409			 * If this fails, the parent does not completely shadow
1410			 * the object and we might as well give up now.
1411			 */
1412
1413			pp = vm_page_lookup(object, new_pindex);
1414			if (
1415			    (pp == NULL || pp->valid == 0) &&
1416			    !vm_pager_has_page(object, new_pindex, NULL, NULL)
1417			) {
1418				r = 0;
1419				break;
1420			}
1421		}
1422
1423		/*
1424		 * Check for busy page
1425		 */
1426		if (op & (OBSC_COLLAPSE_WAIT | OBSC_COLLAPSE_NOWAIT)) {
1427			vm_page_t pp;
1428
1429			vm_page_lock_queues();
1430			if (op & OBSC_COLLAPSE_NOWAIT) {
1431				if ((p->flags & PG_BUSY) ||
1432				    !p->valid ||
1433				    p->hold_count ||
1434				    p->wire_count ||
1435				    p->busy) {
1436					vm_page_unlock_queues();
1437					p = next;
1438					continue;
1439				}
1440			} else if (op & OBSC_COLLAPSE_WAIT) {
1441				if ((p->flags & PG_BUSY) || p->busy) {
1442					vm_page_flag_set(p,
1443					    PG_WANTED | PG_REFERENCED);
1444					VM_OBJECT_UNLOCK(backing_object);
1445					VM_OBJECT_UNLOCK(object);
1446					msleep(p, &vm_page_queue_mtx,
1447					    PDROP | PVM, "vmocol", 0);
1448					VM_OBJECT_LOCK(object);
1449					VM_OBJECT_LOCK(backing_object);
1450					/*
1451					 * If we slept, anything could have
1452					 * happened.  Since the object is
1453					 * marked dead, the backing offset
1454					 * should not have changed so we
1455					 * just restart our scan.
1456					 */
1457					p = TAILQ_FIRST(&backing_object->memq);
1458					continue;
1459				}
1460			}
1461
1462			/*
1463			 * Busy the page
1464			 */
1465			vm_page_busy(p);
1466			vm_page_unlock_queues();
1467
1468			KASSERT(
1469			    p->object == backing_object,
1470			    ("vm_object_qcollapse(): object mismatch")
1471			);
1472
1473			/*
1474			 * Destroy any associated swap
1475			 */
1476			if (backing_object->type == OBJT_SWAP) {
1477				swap_pager_freespace(
1478				    backing_object,
1479				    p->pindex,
1480				    1
1481				);
1482			}
1483
1484			if (
1485			    p->pindex < backing_offset_index ||
1486			    new_pindex >= object->size
1487			) {
1488				/*
1489				 * Page is out of the parent object's range, we
1490				 * can simply destroy it.
1491				 */
1492				vm_page_lock_queues();
1493				pmap_remove_all(p);
1494				vm_page_free(p);
1495				vm_page_unlock_queues();
1496				p = next;
1497				continue;
1498			}
1499
1500			pp = vm_page_lookup(object, new_pindex);
1501			if (
1502			    pp != NULL ||
1503			    vm_pager_has_page(object, new_pindex, NULL, NULL)
1504			) {
1505				/*
1506				 * page already exists in parent OR swap exists
1507				 * for this location in the parent.  Destroy
1508				 * the original page from the backing object.
1509				 *
1510				 * Leave the parent's page alone
1511				 */
1512				vm_page_lock_queues();
1513				pmap_remove_all(p);
1514				vm_page_free(p);
1515				vm_page_unlock_queues();
1516				p = next;
1517				continue;
1518			}
1519
1520			/*
1521			 * Page does not exist in parent, rename the
1522			 * page from the backing object to the main object.
1523			 *
1524			 * If the page was mapped to a process, it can remain
1525			 * mapped through the rename.
1526			 */
1527			vm_page_lock_queues();
1528			vm_page_rename(p, object, new_pindex);
1529			vm_page_unlock_queues();
1530			/* page automatically made dirty by rename */
1531		}
1532		p = next;
1533	}
1534	splx(s);
1535	return (r);
1536}
1537
1538
1539/*
1540 * this version of collapse allows the operation to occur earlier and
1541 * when paging_in_progress is true for an object...  This is not a complete
1542 * operation, but should plug 99.9% of the rest of the leaks.
1543 */
1544static void
1545vm_object_qcollapse(vm_object_t object)
1546{
1547	vm_object_t backing_object = object->backing_object;
1548
1549	VM_OBJECT_LOCK_ASSERT(object, MA_OWNED);
1550	VM_OBJECT_LOCK_ASSERT(backing_object, MA_OWNED);
1551
1552	if (backing_object->ref_count != 1)
1553		return;
1554
1555	backing_object->ref_count += 2;
1556
1557	vm_object_backing_scan(object, OBSC_COLLAPSE_NOWAIT);
1558
1559	backing_object->ref_count -= 2;
1560}
1561
1562/*
1563 *	vm_object_collapse:
1564 *
1565 *	Collapse an object with the object backing it.
1566 *	Pages in the backing object are moved into the
1567 *	parent, and the backing object is deallocated.
1568 */
1569void
1570vm_object_collapse(vm_object_t object)
1571{
1572	VM_OBJECT_LOCK_ASSERT(object, MA_OWNED);
1573
1574	while (TRUE) {
1575		vm_object_t backing_object;
1576
1577		/*
1578		 * Verify that the conditions are right for collapse:
1579		 *
1580		 * The object exists and the backing object exists.
1581		 */
1582		if ((backing_object = object->backing_object) == NULL)
1583			break;
1584
1585		/*
1586		 * we check the backing object first, because it is most likely
1587		 * not collapsable.
1588		 */
1589		VM_OBJECT_LOCK(backing_object);
1590		if (backing_object->handle != NULL ||
1591		    (backing_object->type != OBJT_DEFAULT &&
1592		     backing_object->type != OBJT_SWAP) ||
1593		    (backing_object->flags & OBJ_DEAD) ||
1594		    object->handle != NULL ||
1595		    (object->type != OBJT_DEFAULT &&
1596		     object->type != OBJT_SWAP) ||
1597		    (object->flags & OBJ_DEAD)) {
1598			VM_OBJECT_UNLOCK(backing_object);
1599			break;
1600		}
1601
1602		if (
1603		    object->paging_in_progress != 0 ||
1604		    backing_object->paging_in_progress != 0
1605		) {
1606			vm_object_qcollapse(object);
1607			VM_OBJECT_UNLOCK(backing_object);
1608			break;
1609		}
1610		/*
1611		 * We know that we can either collapse the backing object (if
1612		 * the parent is the only reference to it) or (perhaps) have
1613		 * the parent bypass the object if the parent happens to shadow
1614		 * all the resident pages in the entire backing object.
1615		 *
1616		 * This is ignoring pager-backed pages such as swap pages.
1617		 * vm_object_backing_scan fails the shadowing test in this
1618		 * case.
1619		 */
1620		if (backing_object->ref_count == 1) {
1621			/*
1622			 * If there is exactly one reference to the backing
1623			 * object, we can collapse it into the parent.
1624			 */
1625			vm_object_backing_scan(object, OBSC_COLLAPSE_WAIT);
1626
1627			/*
1628			 * Move the pager from backing_object to object.
1629			 */
1630			if (backing_object->type == OBJT_SWAP) {
1631				/*
1632				 * swap_pager_copy() can sleep, in which case
1633				 * the backing_object's and object's locks are
1634				 * released and reacquired.
1635				 */
1636				swap_pager_copy(
1637				    backing_object,
1638				    object,
1639				    OFF_TO_IDX(object->backing_object_offset), TRUE);
1640			}
1641			/*
1642			 * Object now shadows whatever backing_object did.
1643			 * Note that the reference to
1644			 * backing_object->backing_object moves from within
1645			 * backing_object to within object.
1646			 */
1647			LIST_REMOVE(object, shadow_list);
1648			backing_object->shadow_count--;
1649			backing_object->generation++;
1650			if (backing_object->backing_object) {
1651				VM_OBJECT_LOCK(backing_object->backing_object);
1652				LIST_REMOVE(backing_object, shadow_list);
1653				LIST_INSERT_HEAD(
1654				    &backing_object->backing_object->shadow_head,
1655				    object, shadow_list);
1656				/*
1657				 * The shadow_count has not changed.
1658				 */
1659				backing_object->backing_object->generation++;
1660				VM_OBJECT_UNLOCK(backing_object->backing_object);
1661			}
1662			object->backing_object = backing_object->backing_object;
1663			object->backing_object_offset +=
1664			    backing_object->backing_object_offset;
1665
1666			/*
1667			 * Discard backing_object.
1668			 *
1669			 * Since the backing object has no pages, no pager left,
1670			 * and no object references within it, all that is
1671			 * necessary is to dispose of it.
1672			 */
1673			KASSERT(backing_object->ref_count == 1, ("backing_object %p was somehow re-referenced during collapse!", backing_object));
1674			VM_OBJECT_UNLOCK(backing_object);
1675
1676			mtx_lock(&vm_object_list_mtx);
1677			TAILQ_REMOVE(
1678			    &vm_object_list,
1679			    backing_object,
1680			    object_list
1681			);
1682			mtx_unlock(&vm_object_list_mtx);
1683
1684			uma_zfree(obj_zone, backing_object);
1685
1686			object_collapses++;
1687		} else {
1688			vm_object_t new_backing_object;
1689
1690			/*
1691			 * If we do not entirely shadow the backing object,
1692			 * there is nothing we can do so we give up.
1693			 */
1694			if (vm_object_backing_scan(object, OBSC_TEST_ALL_SHADOWED) == 0) {
1695				VM_OBJECT_UNLOCK(backing_object);
1696				break;
1697			}
1698
1699			/*
1700			 * Make the parent shadow the next object in the
1701			 * chain.  Deallocating backing_object will not remove
1702			 * it, since its reference count is at least 2.
1703			 */
1704			LIST_REMOVE(object, shadow_list);
1705			backing_object->shadow_count--;
1706			backing_object->generation++;
1707
1708			new_backing_object = backing_object->backing_object;
1709			if ((object->backing_object = new_backing_object) != NULL) {
1710				VM_OBJECT_LOCK(new_backing_object);
1711				LIST_INSERT_HEAD(
1712				    &new_backing_object->shadow_head,
1713				    object,
1714				    shadow_list
1715				);
1716				new_backing_object->shadow_count++;
1717				new_backing_object->generation++;
1718				vm_object_reference_locked(new_backing_object);
1719				VM_OBJECT_UNLOCK(new_backing_object);
1720				object->backing_object_offset +=
1721					backing_object->backing_object_offset;
1722			}
1723
1724			/*
1725			 * Drop the reference count on backing_object. Since
1726			 * its ref_count was at least 2, it will not vanish.
1727			 */
1728			backing_object->ref_count--;
1729			VM_OBJECT_UNLOCK(backing_object);
1730			object_bypasses++;
1731		}
1732
1733		/*
1734		 * Try again with this object's new backing object.
1735		 */
1736	}
1737}
1738
1739/*
1740 *	vm_object_page_remove:
1741 *
1742 *	Removes all physical pages in the given range from the
1743 *	object's list of pages.  If the range's end is zero, all
1744 *	physical pages from the range's start to the end of the object
1745 *	are deleted.
1746 *
1747 *	The object must be locked.
1748 */
1749void
1750vm_object_page_remove(vm_object_t object, vm_pindex_t start, vm_pindex_t end,
1751    boolean_t clean_only)
1752{
1753	vm_page_t p, next;
1754
1755	VM_OBJECT_LOCK_ASSERT(object, MA_OWNED);
1756	if (object->resident_page_count == 0)
1757		return;
1758
1759	/*
1760	 * Since physically-backed objects do not use managed pages, we can't
1761	 * remove pages from the object (we must instead remove the page
1762	 * references, and then destroy the object).
1763	 */
1764	KASSERT(object->type != OBJT_PHYS,
1765	    ("attempt to remove pages from a physical object"));
1766
1767	vm_object_pip_add(object, 1);
1768again:
1769	vm_page_lock_queues();
1770	if ((p = TAILQ_FIRST(&object->memq)) != NULL) {
1771		if (p->pindex < start) {
1772			p = vm_page_splay(start, object->root);
1773			if ((object->root = p)->pindex < start)
1774				p = TAILQ_NEXT(p, listq);
1775		}
1776	}
1777	/*
1778	 * Assert: the variable p is either (1) the page with the
1779	 * least pindex greater than or equal to the parameter pindex
1780	 * or (2) NULL.
1781	 */
1782	for (;
1783	     p != NULL && (p->pindex < end || end == 0);
1784	     p = next) {
1785		next = TAILQ_NEXT(p, listq);
1786
1787		if (p->wire_count != 0) {
1788			pmap_remove_all(p);
1789			if (!clean_only)
1790				p->valid = 0;
1791			continue;
1792		}
1793		if (vm_page_sleep_if_busy(p, TRUE, "vmopar"))
1794			goto again;
1795		if (clean_only && p->valid) {
1796			vm_page_test_dirty(p);
1797			if (p->valid & p->dirty)
1798				continue;
1799		}
1800		vm_page_busy(p);
1801		pmap_remove_all(p);
1802		vm_page_free(p);
1803	}
1804	vm_page_unlock_queues();
1805	vm_object_pip_wakeup(object);
1806}
1807
1808/*
1809 *	Routine:	vm_object_coalesce
1810 *	Function:	Coalesces two objects backing up adjoining
1811 *			regions of memory into a single object.
1812 *
1813 *	returns TRUE if objects were combined.
1814 *
1815 *	NOTE:	Only works at the moment if the second object is NULL -
1816 *		if it's not, which object do we lock first?
1817 *
1818 *	Parameters:
1819 *		prev_object	First object to coalesce
1820 *		prev_offset	Offset into prev_object
1821 *		next_object	Second object into coalesce
1822 *		next_offset	Offset into next_object
1823 *
1824 *		prev_size	Size of reference to prev_object
1825 *		next_size	Size of reference to next_object
1826 *
1827 *	Conditions:
1828 *	The object must *not* be locked.
1829 */
1830boolean_t
1831vm_object_coalesce(vm_object_t prev_object, vm_pindex_t prev_pindex,
1832	vm_size_t prev_size, vm_size_t next_size)
1833{
1834	vm_pindex_t next_pindex;
1835
1836	if (prev_object == NULL)
1837		return (TRUE);
1838	VM_OBJECT_LOCK(prev_object);
1839	if (prev_object->type != OBJT_DEFAULT &&
1840	    prev_object->type != OBJT_SWAP) {
1841		VM_OBJECT_UNLOCK(prev_object);
1842		return (FALSE);
1843	}
1844
1845	/*
1846	 * Try to collapse the object first
1847	 */
1848	vm_object_collapse(prev_object);
1849
1850	/*
1851	 * Can't coalesce if: . more than one reference . paged out . shadows
1852	 * another object . has a copy elsewhere (any of which mean that the
1853	 * pages not mapped to prev_entry may be in use anyway)
1854	 */
1855	if (prev_object->backing_object != NULL) {
1856		VM_OBJECT_UNLOCK(prev_object);
1857		return (FALSE);
1858	}
1859
1860	prev_size >>= PAGE_SHIFT;
1861	next_size >>= PAGE_SHIFT;
1862	next_pindex = prev_pindex + prev_size;
1863
1864	if ((prev_object->ref_count > 1) &&
1865	    (prev_object->size != next_pindex)) {
1866		VM_OBJECT_UNLOCK(prev_object);
1867		return (FALSE);
1868	}
1869
1870	/*
1871	 * Remove any pages that may still be in the object from a previous
1872	 * deallocation.
1873	 */
1874	if (next_pindex < prev_object->size) {
1875		vm_object_page_remove(prev_object,
1876				      next_pindex,
1877				      next_pindex + next_size, FALSE);
1878		if (prev_object->type == OBJT_SWAP)
1879			swap_pager_freespace(prev_object,
1880					     next_pindex, next_size);
1881	}
1882
1883	/*
1884	 * Extend the object if necessary.
1885	 */
1886	if (next_pindex + next_size > prev_object->size)
1887		prev_object->size = next_pindex + next_size;
1888
1889	VM_OBJECT_UNLOCK(prev_object);
1890	return (TRUE);
1891}
1892
1893void
1894vm_object_set_writeable_dirty(vm_object_t object)
1895{
1896	struct vnode *vp;
1897
1898	VM_OBJECT_LOCK_ASSERT(object, MA_OWNED);
1899	vm_object_set_flag(object, OBJ_WRITEABLE|OBJ_MIGHTBEDIRTY);
1900	if (object->type == OBJT_VNODE &&
1901	    (vp = (struct vnode *)object->handle) != NULL) {
1902		VI_LOCK(vp);
1903		if ((vp->v_iflag & VI_OBJDIRTY) == 0)
1904			vp->v_iflag |= VI_OBJDIRTY;
1905		VI_UNLOCK(vp);
1906	}
1907}
1908
1909#include "opt_ddb.h"
1910#ifdef DDB
1911#include <sys/kernel.h>
1912
1913#include <sys/cons.h>
1914
1915#include <ddb/ddb.h>
1916
1917static int
1918_vm_object_in_map(vm_map_t map, vm_object_t object, vm_map_entry_t entry)
1919{
1920	vm_map_t tmpm;
1921	vm_map_entry_t tmpe;
1922	vm_object_t obj;
1923	int entcount;
1924
1925	if (map == 0)
1926		return 0;
1927
1928	if (entry == 0) {
1929		tmpe = map->header.next;
1930		entcount = map->nentries;
1931		while (entcount-- && (tmpe != &map->header)) {
1932			if (_vm_object_in_map(map, object, tmpe)) {
1933				return 1;
1934			}
1935			tmpe = tmpe->next;
1936		}
1937	} else if (entry->eflags & MAP_ENTRY_IS_SUB_MAP) {
1938		tmpm = entry->object.sub_map;
1939		tmpe = tmpm->header.next;
1940		entcount = tmpm->nentries;
1941		while (entcount-- && tmpe != &tmpm->header) {
1942			if (_vm_object_in_map(tmpm, object, tmpe)) {
1943				return 1;
1944			}
1945			tmpe = tmpe->next;
1946		}
1947	} else if ((obj = entry->object.vm_object) != NULL) {
1948		for (; obj; obj = obj->backing_object)
1949			if (obj == object) {
1950				return 1;
1951			}
1952	}
1953	return 0;
1954}
1955
1956static int
1957vm_object_in_map(vm_object_t object)
1958{
1959	struct proc *p;
1960
1961	/* sx_slock(&allproc_lock); */
1962	LIST_FOREACH(p, &allproc, p_list) {
1963		if (!p->p_vmspace /* || (p->p_flag & (P_SYSTEM|P_WEXIT)) */)
1964			continue;
1965		if (_vm_object_in_map(&p->p_vmspace->vm_map, object, 0)) {
1966			/* sx_sunlock(&allproc_lock); */
1967			return 1;
1968		}
1969	}
1970	/* sx_sunlock(&allproc_lock); */
1971	if (_vm_object_in_map(kernel_map, object, 0))
1972		return 1;
1973	if (_vm_object_in_map(kmem_map, object, 0))
1974		return 1;
1975	if (_vm_object_in_map(pager_map, object, 0))
1976		return 1;
1977	if (_vm_object_in_map(buffer_map, object, 0))
1978		return 1;
1979	return 0;
1980}
1981
1982DB_SHOW_COMMAND(vmochk, vm_object_check)
1983{
1984	vm_object_t object;
1985
1986	/*
1987	 * make sure that internal objs are in a map somewhere
1988	 * and none have zero ref counts.
1989	 */
1990	TAILQ_FOREACH(object, &vm_object_list, object_list) {
1991		if (object->handle == NULL &&
1992		    (object->type == OBJT_DEFAULT || object->type == OBJT_SWAP)) {
1993			if (object->ref_count == 0) {
1994				db_printf("vmochk: internal obj has zero ref count: %ld\n",
1995					(long)object->size);
1996			}
1997			if (!vm_object_in_map(object)) {
1998				db_printf(
1999			"vmochk: internal obj is not in a map: "
2000			"ref: %d, size: %lu: 0x%lx, backing_object: %p\n",
2001				    object->ref_count, (u_long)object->size,
2002				    (u_long)object->size,
2003				    (void *)object->backing_object);
2004			}
2005		}
2006	}
2007}
2008
2009/*
2010 *	vm_object_print:	[ debug ]
2011 */
2012DB_SHOW_COMMAND(object, vm_object_print_static)
2013{
2014	/* XXX convert args. */
2015	vm_object_t object = (vm_object_t)addr;
2016	boolean_t full = have_addr;
2017
2018	vm_page_t p;
2019
2020	/* XXX count is an (unused) arg.  Avoid shadowing it. */
2021#define	count	was_count
2022
2023	int count;
2024
2025	if (object == NULL)
2026		return;
2027
2028	db_iprintf(
2029	    "Object %p: type=%d, size=0x%jx, res=%d, ref=%d, flags=0x%x\n",
2030	    object, (int)object->type, (uintmax_t)object->size,
2031	    object->resident_page_count, object->ref_count, object->flags);
2032	db_iprintf(" sref=%d, backing_object(%d)=(%p)+0x%jx\n",
2033	    object->shadow_count,
2034	    object->backing_object ? object->backing_object->ref_count : 0,
2035	    object->backing_object, (uintmax_t)object->backing_object_offset);
2036
2037	if (!full)
2038		return;
2039
2040	db_indent += 2;
2041	count = 0;
2042	TAILQ_FOREACH(p, &object->memq, listq) {
2043		if (count == 0)
2044			db_iprintf("memory:=");
2045		else if (count == 6) {
2046			db_printf("\n");
2047			db_iprintf(" ...");
2048			count = 0;
2049		} else
2050			db_printf(",");
2051		count++;
2052
2053		db_printf("(off=0x%jx,page=0x%jx)",
2054		    (uintmax_t)p->pindex, (uintmax_t)VM_PAGE_TO_PHYS(p));
2055	}
2056	if (count != 0)
2057		db_printf("\n");
2058	db_indent -= 2;
2059}
2060
2061/* XXX. */
2062#undef count
2063
2064/* XXX need this non-static entry for calling from vm_map_print. */
2065void
2066vm_object_print(
2067        /* db_expr_t */ long addr,
2068	boolean_t have_addr,
2069	/* db_expr_t */ long count,
2070	char *modif)
2071{
2072	vm_object_print_static(addr, have_addr, count, modif);
2073}
2074
2075DB_SHOW_COMMAND(vmopag, vm_object_print_pages)
2076{
2077	vm_object_t object;
2078	int nl = 0;
2079	int c;
2080
2081	TAILQ_FOREACH(object, &vm_object_list, object_list) {
2082		vm_pindex_t idx, fidx;
2083		vm_pindex_t osize;
2084		vm_paddr_t pa = -1, padiff;
2085		int rcount;
2086		vm_page_t m;
2087
2088		db_printf("new object: %p\n", (void *)object);
2089		if (nl > 18) {
2090			c = cngetc();
2091			if (c != ' ')
2092				return;
2093			nl = 0;
2094		}
2095		nl++;
2096		rcount = 0;
2097		fidx = 0;
2098		osize = object->size;
2099		if (osize > 128)
2100			osize = 128;
2101		for (idx = 0; idx < osize; idx++) {
2102			m = vm_page_lookup(object, idx);
2103			if (m == NULL) {
2104				if (rcount) {
2105					db_printf(" index(%ld)run(%d)pa(0x%lx)\n",
2106						(long)fidx, rcount, (long)pa);
2107					if (nl > 18) {
2108						c = cngetc();
2109						if (c != ' ')
2110							return;
2111						nl = 0;
2112					}
2113					nl++;
2114					rcount = 0;
2115				}
2116				continue;
2117			}
2118
2119
2120			if (rcount &&
2121				(VM_PAGE_TO_PHYS(m) == pa + rcount * PAGE_SIZE)) {
2122				++rcount;
2123				continue;
2124			}
2125			if (rcount) {
2126				padiff = pa + rcount * PAGE_SIZE - VM_PAGE_TO_PHYS(m);
2127				padiff >>= PAGE_SHIFT;
2128				padiff &= PQ_L2_MASK;
2129				if (padiff == 0) {
2130					pa = VM_PAGE_TO_PHYS(m) - rcount * PAGE_SIZE;
2131					++rcount;
2132					continue;
2133				}
2134				db_printf(" index(%ld)run(%d)pa(0x%lx)",
2135					(long)fidx, rcount, (long)pa);
2136				db_printf("pd(%ld)\n", (long)padiff);
2137				if (nl > 18) {
2138					c = cngetc();
2139					if (c != ' ')
2140						return;
2141					nl = 0;
2142				}
2143				nl++;
2144			}
2145			fidx = idx;
2146			pa = VM_PAGE_TO_PHYS(m);
2147			rcount = 1;
2148		}
2149		if (rcount) {
2150			db_printf(" index(%ld)run(%d)pa(0x%lx)\n",
2151				(long)fidx, rcount, (long)pa);
2152			if (nl > 18) {
2153				c = cngetc();
2154				if (c != ' ')
2155					return;
2156				nl = 0;
2157			}
2158			nl++;
2159		}
2160	}
2161}
2162#endif /* DDB */
2163