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 * 4. Neither the name of the University nor the names of its contributors
17 * may be used to endorse or promote products derived from this software
18 * without specific prior written permission.
19 *
20 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
21 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
22 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
23 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
24 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
25 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
26 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
27 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
28 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
29 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
30 * SUCH DAMAGE.
31 *
32 * from: @(#)vm_object.c 8.5 (Berkeley) 3/22/94
33 *
34 *
35 * Copyright (c) 1987, 1990 Carnegie-Mellon University.
36 * All rights reserved.
37 *
38 * Authors: Avadis Tevanian, Jr., Michael Wayne Young
39 *
40 * Permission to use, copy, modify and distribute this software and
41 * its documentation is hereby granted, provided that both the copyright
42 * notice and this permission notice appear in all copies of the
43 * software, derivative works or modified versions, and any portions
44 * thereof, and that both notices appear in supporting documentation.
45 *
46 * CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS"
47 * CONDITION. CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND
48 * FOR ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
49 *
50 * Carnegie Mellon requests users of this software to return to
51 *
52 * Software Distribution Coordinator or Software.Distribution@CS.CMU.EDU
53 * School of Computer Science
54 * Carnegie Mellon University
55 * Pittsburgh PA 15213-3890
56 *
57 * any improvements or extensions that they make and grant Carnegie the
58 * rights to redistribute these changes.
59 */
60
61/*
62 * Virtual memory object module.
63 */
64
65#include <sys/cdefs.h>
66__FBSDID("$FreeBSD: head/sys/vm/vm_object.c 254025 2013-08-07 06:21:20Z jeff $");
67
68#include "opt_vm.h"
69
70#include <sys/param.h>
71#include <sys/systm.h>
72#include <sys/lock.h>
73#include <sys/mman.h>
74#include <sys/mount.h>
75#include <sys/kernel.h>
76#include <sys/sysctl.h>
77#include <sys/mutex.h>
78#include <sys/proc.h> /* for curproc, pageproc */
79#include <sys/socket.h>
80#include <sys/resourcevar.h>
81#include <sys/rwlock.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/vm_radix.h>
98#include <vm/vm_reserv.h>
99#include <vm/uma.h>
100
101static int old_msync;
102SYSCTL_INT(_vm, OID_AUTO, old_msync, CTLFLAG_RW, &old_msync, 0,
103 "Use old (insecure) msync behavior");
104
105static int vm_object_page_collect_flush(vm_object_t object, vm_page_t p,
106 int pagerflags, int flags, boolean_t *clearobjflags,
107 boolean_t *eio);
108static boolean_t vm_object_page_remove_write(vm_page_t p, int flags,
109 boolean_t *clearobjflags);
110static void vm_object_qcollapse(vm_object_t object);
111static void vm_object_vndeallocate(vm_object_t object);
112
113/*
114 * Virtual memory objects maintain the actual data
115 * associated with allocated virtual memory. A given
116 * page of memory exists within exactly one object.
117 *
118 * An object is only deallocated when all "references"
119 * are given up. Only one "reference" to a given
120 * region of an object should be writeable.
121 *
122 * Associated with each object is a list of all resident
123 * memory pages belonging to that object; this list is
124 * maintained by the "vm_page" module, and locked by the object's
125 * lock.
126 *
127 * Each object also records a "pager" routine which is
128 * used to retrieve (and store) pages to the proper backing
129 * storage. In addition, objects may be backed by other
130 * objects from which they were virtual-copied.
131 *
132 * The only items within the object structure which are
133 * modified after time of creation are:
134 * reference count locked by object's lock
135 * pager routine locked by object's lock
136 *
137 */
138
139struct object_q vm_object_list;
140struct mtx vm_object_list_mtx; /* lock for object list and count */
141
142struct vm_object kernel_object_store;
143struct vm_object kmem_object_store;
144
145static SYSCTL_NODE(_vm_stats, OID_AUTO, object, CTLFLAG_RD, 0,
146 "VM object stats");
147
148static long object_collapses;
149SYSCTL_LONG(_vm_stats_object, OID_AUTO, collapses, CTLFLAG_RD,
150 &object_collapses, 0, "VM object collapses");
151
152static long object_bypasses;
153SYSCTL_LONG(_vm_stats_object, OID_AUTO, bypasses, CTLFLAG_RD,
154 &object_bypasses, 0, "VM object bypasses");
155
156static uma_zone_t obj_zone;
157
158static int vm_object_zinit(void *mem, int size, int flags);
159
160#ifdef INVARIANTS
161static void vm_object_zdtor(void *mem, int size, void *arg);
162
163static void
164vm_object_zdtor(void *mem, int size, void *arg)
165{
166 vm_object_t object;
167
168 object = (vm_object_t)mem;
169 KASSERT(TAILQ_EMPTY(&object->memq),
170 ("object %p has resident pages in its memq", object));
171 KASSERT(vm_radix_is_empty(&object->rtree),
172 ("object %p has resident pages in its trie", object));
173#if VM_NRESERVLEVEL > 0
174 KASSERT(LIST_EMPTY(&object->rvq),
175 ("object %p has reservations",
176 object));
177#endif
178 KASSERT(vm_object_cache_is_empty(object),
179 ("object %p has cached pages",
180 object));
181 KASSERT(object->paging_in_progress == 0,
182 ("object %p paging_in_progress = %d",
183 object, object->paging_in_progress));
184 KASSERT(object->resident_page_count == 0,
185 ("object %p resident_page_count = %d",
186 object, object->resident_page_count));
187 KASSERT(object->shadow_count == 0,
188 ("object %p shadow_count = %d",
189 object, object->shadow_count));
190}
191#endif
192
193static int
194vm_object_zinit(void *mem, int size, int flags)
195{
196 vm_object_t object;
197
198 object = (vm_object_t)mem;
199 bzero(&object->lock, sizeof(object->lock));
200 rw_init_flags(&object->lock, "vm object", RW_DUPOK);
201
202 /* These are true for any object that has been freed */
203 object->rtree.rt_root = 0;
204 object->paging_in_progress = 0;
205 object->resident_page_count = 0;
206 object->shadow_count = 0;
207 object->cache.rt_root = 0;
208 return (0);
209}
210
211static void
212_vm_object_allocate(objtype_t type, vm_pindex_t size, vm_object_t object)
213{
214
215 TAILQ_INIT(&object->memq);
216 LIST_INIT(&object->shadow_head);
217
218 object->type = type;
219 switch (type) {
220 case OBJT_DEAD:
221 panic("_vm_object_allocate: can't create OBJT_DEAD");
222 case OBJT_DEFAULT:
223 case OBJT_SWAP:
224 object->flags = OBJ_ONEMAPPING;
225 break;
226 case OBJT_DEVICE:
227 case OBJT_SG:
228 object->flags = OBJ_FICTITIOUS | OBJ_UNMANAGED;
229 break;
230 case OBJT_MGTDEVICE:
231 object->flags = OBJ_FICTITIOUS;
232 break;
233 case OBJT_PHYS:
234 object->flags = OBJ_UNMANAGED;
235 break;
236 case OBJT_VNODE:
237 object->flags = 0;
238 break;
239 default:
240 panic("_vm_object_allocate: type %d is undefined", type);
241 }
242 object->size = size;
243 object->generation = 1;
244 object->ref_count = 1;
245 object->memattr = VM_MEMATTR_DEFAULT;
246 object->cred = NULL;
247 object->charge = 0;
248 object->handle = NULL;
249 object->backing_object = NULL;
250 object->backing_object_offset = (vm_ooffset_t) 0;
251#if VM_NRESERVLEVEL > 0
252 LIST_INIT(&object->rvq);
253#endif
254
255 mtx_lock(&vm_object_list_mtx);
256 TAILQ_INSERT_TAIL(&vm_object_list, object, object_list);
257 mtx_unlock(&vm_object_list_mtx);
258}
259
260/*
261 * vm_object_init:
262 *
263 * Initialize the VM objects module.
264 */
265void
266vm_object_init(void)
267{
268 TAILQ_INIT(&vm_object_list);
269 mtx_init(&vm_object_list_mtx, "vm object_list", NULL, MTX_DEF);
270
271 rw_init(&kernel_object->lock, "kernel vm object");
272 _vm_object_allocate(OBJT_PHYS, OFF_TO_IDX(VM_MAX_KERNEL_ADDRESS - VM_MIN_KERNEL_ADDRESS),
273 kernel_object);
274#if VM_NRESERVLEVEL > 0
275 kernel_object->flags |= OBJ_COLORED;
276 kernel_object->pg_color = (u_short)atop(VM_MIN_KERNEL_ADDRESS);
277#endif
278
279 rw_init(&kmem_object->lock, "kmem vm object");
280 _vm_object_allocate(OBJT_PHYS, OFF_TO_IDX(VM_MAX_KERNEL_ADDRESS - VM_MIN_KERNEL_ADDRESS),
281 kmem_object);
282#if VM_NRESERVLEVEL > 0
283 kmem_object->flags |= OBJ_COLORED;
284 kmem_object->pg_color = (u_short)atop(VM_MIN_KERNEL_ADDRESS);
285#endif
286
287 /*
288 * The lock portion of struct vm_object must be type stable due
289 * to vm_pageout_fallback_object_lock locking a vm object
290 * without holding any references to it.
291 */
292 obj_zone = uma_zcreate("VM OBJECT", sizeof (struct vm_object), NULL,
293#ifdef INVARIANTS
294 vm_object_zdtor,
295#else
296 NULL,
297#endif
298 vm_object_zinit, NULL, UMA_ALIGN_PTR, UMA_ZONE_NOFREE);
299
300 vm_radix_init();
301}
302
303void
304vm_object_clear_flag(vm_object_t object, u_short bits)
305{
306
307 VM_OBJECT_ASSERT_WLOCKED(object);
308 object->flags &= ~bits;
309}
310
311/*
312 * Sets the default memory attribute for the specified object. Pages
313 * that are allocated to this object are by default assigned this memory
314 * attribute.
315 *
316 * Presently, this function must be called before any pages are allocated
317 * to the object. In the future, this requirement may be relaxed for
318 * "default" and "swap" objects.
319 */
320int
321vm_object_set_memattr(vm_object_t object, vm_memattr_t memattr)
322{
323
324 VM_OBJECT_ASSERT_WLOCKED(object);
325 switch (object->type) {
326 case OBJT_DEFAULT:
327 case OBJT_DEVICE:
328 case OBJT_MGTDEVICE:
329 case OBJT_PHYS:
330 case OBJT_SG:
331 case OBJT_SWAP:
332 case OBJT_VNODE:
333 if (!TAILQ_EMPTY(&object->memq))
334 return (KERN_FAILURE);
335 break;
336 case OBJT_DEAD:
337 return (KERN_INVALID_ARGUMENT);
338 default:
339 panic("vm_object_set_memattr: object %p is of undefined type",
340 object);
341 }
342 object->memattr = memattr;
343 return (KERN_SUCCESS);
344}
345
346void
347vm_object_pip_add(vm_object_t object, short i)
348{
349
350 VM_OBJECT_ASSERT_WLOCKED(object);
351 object->paging_in_progress += i;
352}
353
354void
355vm_object_pip_subtract(vm_object_t object, short i)
356{
357
358 VM_OBJECT_ASSERT_WLOCKED(object);
359 object->paging_in_progress -= i;
360}
361
362void
363vm_object_pip_wakeup(vm_object_t object)
364{
365
366 VM_OBJECT_ASSERT_WLOCKED(object);
367 object->paging_in_progress--;
368 if ((object->flags & OBJ_PIPWNT) && object->paging_in_progress == 0) {
369 vm_object_clear_flag(object, OBJ_PIPWNT);
370 wakeup(object);
371 }
372}
373
374void
375vm_object_pip_wakeupn(vm_object_t object, short i)
376{
377
378 VM_OBJECT_ASSERT_WLOCKED(object);
379 if (i)
380 object->paging_in_progress -= i;
381 if ((object->flags & OBJ_PIPWNT) && object->paging_in_progress == 0) {
382 vm_object_clear_flag(object, OBJ_PIPWNT);
383 wakeup(object);
384 }
385}
386
387void
388vm_object_pip_wait(vm_object_t object, char *waitid)
389{
390
391 VM_OBJECT_ASSERT_WLOCKED(object);
392 while (object->paging_in_progress) {
393 object->flags |= OBJ_PIPWNT;
394 VM_OBJECT_SLEEP(object, object, PVM, waitid, 0);
395 }
396}
397
398/*
399 * vm_object_allocate:
400 *
401 * Returns a new object with the given size.
402 */
403vm_object_t
404vm_object_allocate(objtype_t type, vm_pindex_t size)
405{
406 vm_object_t object;
407
408 object = (vm_object_t)uma_zalloc(obj_zone, M_WAITOK);
409 _vm_object_allocate(type, size, object);
410 return (object);
411}
412
413
414/*
415 * vm_object_reference:
416 *
417 * Gets another reference to the given object. Note: OBJ_DEAD
418 * objects can be referenced during final cleaning.
419 */
420void
421vm_object_reference(vm_object_t object)
422{
423 if (object == NULL)
424 return;
425 VM_OBJECT_WLOCK(object);
426 vm_object_reference_locked(object);
427 VM_OBJECT_WUNLOCK(object);
428}
429
430/*
431 * vm_object_reference_locked:
432 *
433 * Gets another reference to the given object.
434 *
435 * The object must be locked.
436 */
437void
438vm_object_reference_locked(vm_object_t object)
439{
440 struct vnode *vp;
441
442 VM_OBJECT_ASSERT_WLOCKED(object);
443 object->ref_count++;
444 if (object->type == OBJT_VNODE) {
445 vp = object->handle;
446 vref(vp);
447 }
448}
449
450/*
451 * Handle deallocating an object of type OBJT_VNODE.
452 */
453static void
454vm_object_vndeallocate(vm_object_t object)
455{
456 struct vnode *vp = (struct vnode *) object->handle;
457
458 VM_OBJECT_ASSERT_WLOCKED(object);
459 KASSERT(object->type == OBJT_VNODE,
460 ("vm_object_vndeallocate: not a vnode object"));
461 KASSERT(vp != NULL, ("vm_object_vndeallocate: missing vp"));
462#ifdef INVARIANTS
463 if (object->ref_count == 0) {
464 vprint("vm_object_vndeallocate", vp);
465 panic("vm_object_vndeallocate: bad object reference count");
466 }
467#endif
468
469 if (object->ref_count > 1) {
470 object->ref_count--;
471 VM_OBJECT_WUNLOCK(object);
472 /* vrele may need the vnode lock. */
473 vrele(vp);
474 } else {
475 vhold(vp);
476 VM_OBJECT_WUNLOCK(object);
477 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
478 vdrop(vp);
479 VM_OBJECT_WLOCK(object);
480 object->ref_count--;
481 if (object->type == OBJT_DEAD) {
482 VM_OBJECT_WUNLOCK(object);
483 VOP_UNLOCK(vp, 0);
484 } else {
485 if (object->ref_count == 0)
486 VOP_UNSET_TEXT(vp);
487 VM_OBJECT_WUNLOCK(object);
488 vput(vp);
489 }
490 }
491}
492
493/*
494 * vm_object_deallocate:
495 *
496 * Release a reference to the specified object,
497 * gained either through a vm_object_allocate
498 * or a vm_object_reference call. When all references
499 * are gone, storage associated with this object
500 * may be relinquished.
501 *
502 * No object may be locked.
503 */
504void
505vm_object_deallocate(vm_object_t object)
506{
507 vm_object_t temp;
508 struct vnode *vp;
509
510 while (object != NULL) {
511 VM_OBJECT_WLOCK(object);
512 if (object->type == OBJT_VNODE) {
513 vm_object_vndeallocate(object);
514 return;
515 }
516
517 KASSERT(object->ref_count != 0,
518 ("vm_object_deallocate: object deallocated too many times: %d", object->type));
519
520 /*
521 * If the reference count goes to 0 we start calling
522 * vm_object_terminate() on the object chain.
523 * A ref count of 1 may be a special case depending on the
524 * shadow count being 0 or 1.
525 */
526 object->ref_count--;
527 if (object->ref_count > 1) {
528 VM_OBJECT_WUNLOCK(object);
529 return;
530 } else if (object->ref_count == 1) {
531 if (object->type == OBJT_SWAP &&
532 (object->flags & OBJ_TMPFS) != 0) {
533 vp = object->un_pager.swp.swp_tmpfs;
534 vhold(vp);
535 VM_OBJECT_WUNLOCK(object);
536 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
537 vdrop(vp);
538 VM_OBJECT_WLOCK(object);
539 if (object->type == OBJT_DEAD ||
540 object->ref_count != 1) {
541 VM_OBJECT_WUNLOCK(object);
542 VOP_UNLOCK(vp, 0);
543 return;
544 }
545 if ((object->flags & OBJ_TMPFS) != 0)
546 VOP_UNSET_TEXT(vp);
547 VOP_UNLOCK(vp, 0);
548 }
549 if (object->shadow_count == 0 &&
550 object->handle == NULL &&
551 (object->type == OBJT_DEFAULT ||
552 (object->type == OBJT_SWAP &&
553 (object->flags & OBJ_TMPFS) == 0))) {
554 vm_object_set_flag(object, OBJ_ONEMAPPING);
555 } else if ((object->shadow_count == 1) &&
556 (object->handle == NULL) &&
557 (object->type == OBJT_DEFAULT ||
558 object->type == OBJT_SWAP)) {
559 KASSERT((object->flags & OBJ_TMPFS) == 0,
560 ("shadowed tmpfs v_object %p", object));
561 vm_object_t robject;
562
563 robject = LIST_FIRST(&object->shadow_head);
564 KASSERT(robject != NULL,
565 ("vm_object_deallocate: ref_count: %d, shadow_count: %d",
566 object->ref_count,
567 object->shadow_count));
568 if (!VM_OBJECT_TRYWLOCK(robject)) {
569 /*
570 * Avoid a potential deadlock.
571 */
572 object->ref_count++;
573 VM_OBJECT_WUNLOCK(object);
574 /*
575 * More likely than not the thread
576 * holding robject's lock has lower
577 * priority than the current thread.
578 * Let the lower priority thread run.
579 */
580 pause("vmo_de", 1);
581 continue;
582 }
583 /*
584 * Collapse object into its shadow unless its
585 * shadow is dead. In that case, object will
586 * be deallocated by the thread that is
587 * deallocating its shadow.
588 */
589 if ((robject->flags & OBJ_DEAD) == 0 &&
590 (robject->handle == NULL) &&
591 (robject->type == OBJT_DEFAULT ||
592 robject->type == OBJT_SWAP)) {
593
594 robject->ref_count++;
595retry:
596 if (robject->paging_in_progress) {
597 VM_OBJECT_WUNLOCK(object);
598 vm_object_pip_wait(robject,
599 "objde1");
600 temp = robject->backing_object;
601 if (object == temp) {
602 VM_OBJECT_WLOCK(object);
603 goto retry;
604 }
605 } else if (object->paging_in_progress) {
606 VM_OBJECT_WUNLOCK(robject);
607 object->flags |= OBJ_PIPWNT;
608 VM_OBJECT_SLEEP(object, object,
609 PDROP | PVM, "objde2", 0);
610 VM_OBJECT_WLOCK(robject);
611 temp = robject->backing_object;
612 if (object == temp) {
613 VM_OBJECT_WLOCK(object);
614 goto retry;
615 }
616 } else
617 VM_OBJECT_WUNLOCK(object);
618
619 if (robject->ref_count == 1) {
620 robject->ref_count--;
621 object = robject;
622 goto doterm;
623 }
624 object = robject;
625 vm_object_collapse(object);
626 VM_OBJECT_WUNLOCK(object);
627 continue;
628 }
629 VM_OBJECT_WUNLOCK(robject);
630 }
631 VM_OBJECT_WUNLOCK(object);
632 return;
633 }
634doterm:
635 temp = object->backing_object;
636 if (temp != NULL) {
637 VM_OBJECT_WLOCK(temp);
638 LIST_REMOVE(object, shadow_list);
639 temp->shadow_count--;
640 VM_OBJECT_WUNLOCK(temp);
641 object->backing_object = NULL;
642 }
643 /*
644 * Don't double-terminate, we could be in a termination
645 * recursion due to the terminate having to sync data
646 * to disk.
647 */
648 if ((object->flags & OBJ_DEAD) == 0)
649 vm_object_terminate(object);
650 else
651 VM_OBJECT_WUNLOCK(object);
652 object = temp;
653 }
654}
655
656/*
657 * vm_object_destroy removes the object from the global object list
658 * and frees the space for the object.
659 */
660void
661vm_object_destroy(vm_object_t object)
662{
663
664 /*
665 * Remove the object from the global object list.
666 */
667 mtx_lock(&vm_object_list_mtx);
668 TAILQ_REMOVE(&vm_object_list, object, object_list);
669 mtx_unlock(&vm_object_list_mtx);
670
671 /*
672 * Release the allocation charge.
673 */
674 if (object->cred != NULL) {
675 KASSERT(object->type == OBJT_DEFAULT ||
676 object->type == OBJT_SWAP,
677 ("vm_object_terminate: non-swap obj %p has cred",
678 object));
679 swap_release_by_cred(object->charge, object->cred);
680 object->charge = 0;
681 crfree(object->cred);
682 object->cred = NULL;
683 }
684
685 /*
686 * Free the space for the object.
687 */
688 uma_zfree(obj_zone, object);
689}
690
691/*
692 * vm_object_terminate actually destroys the specified object, freeing
693 * up all previously used resources.
694 *
695 * The object must be locked.
696 * This routine may block.
697 */
698void
699vm_object_terminate(vm_object_t object)
700{
701 vm_page_t p, p_next;
702
703 VM_OBJECT_ASSERT_WLOCKED(object);
704
705 /*
706 * Make sure no one uses us.
707 */
708 vm_object_set_flag(object, OBJ_DEAD);
709
710 /*
711 * wait for the pageout daemon to be done with the object
712 */
713 vm_object_pip_wait(object, "objtrm");
714
715 KASSERT(!object->paging_in_progress,
716 ("vm_object_terminate: pageout in progress"));
717
718 /*
719 * Clean and free the pages, as appropriate. All references to the
720 * object are gone, so we don't need to lock it.
721 */
722 if (object->type == OBJT_VNODE) {
723 struct vnode *vp = (struct vnode *)object->handle;
724
725 /*
726 * Clean pages and flush buffers.
727 */
728 vm_object_page_clean(object, 0, 0, OBJPC_SYNC);
729 VM_OBJECT_WUNLOCK(object);
730
731 vinvalbuf(vp, V_SAVE, 0, 0);
732
733 VM_OBJECT_WLOCK(object);
734 }
735
736 KASSERT(object->ref_count == 0,
737 ("vm_object_terminate: object with references, ref_count=%d",
738 object->ref_count));
739
740 /*
741 * Free any remaining pageable pages. This also removes them from the
742 * paging queues. However, don't free wired pages, just remove them
743 * from the object. Rather than incrementally removing each page from
744 * the object, the page and object are reset to any empty state.
745 */
746 TAILQ_FOREACH_SAFE(p, &object->memq, listq, p_next) {
747 KASSERT(!p->busy && (p->oflags & VPO_BUSY) == 0,
748 ("vm_object_terminate: freeing busy page %p", p));
749 vm_page_lock(p);
750 /*
751 * Optimize the page's removal from the object by resetting
752 * its "object" field. Specifically, if the page is not
753 * wired, then the effect of this assignment is that
754 * vm_page_free()'s call to vm_page_remove() will return
755 * immediately without modifying the page or the object.
756 */
757 p->object = NULL;
758 if (p->wire_count == 0) {
759 vm_page_free(p);
760 PCPU_INC(cnt.v_pfree);
761 }
762 vm_page_unlock(p);
763 }
764 /*
765 * If the object contained any pages, then reset it to an empty state.
766 * None of the object's fields, including "resident_page_count", were
767 * modified by the preceding loop.
768 */
769 if (object->resident_page_count != 0) {
770 vm_radix_reclaim_allnodes(&object->rtree);
771 TAILQ_INIT(&object->memq);
772 object->resident_page_count = 0;
773 if (object->type == OBJT_VNODE)
774 vdrop(object->handle);
775 }
776
777#if VM_NRESERVLEVEL > 0
778 if (__predict_false(!LIST_EMPTY(&object->rvq)))
779 vm_reserv_break_all(object);
780#endif
781 if (__predict_false(!vm_object_cache_is_empty(object)))
782 vm_page_cache_free(object, 0, 0);
783
784 /*
785 * Let the pager know object is dead.
786 */
787 vm_pager_deallocate(object);
788 VM_OBJECT_WUNLOCK(object);
789
790 vm_object_destroy(object);
791}
792
793/*
794 * Make the page read-only so that we can clear the object flags. However, if
795 * this is a nosync mmap then the object is likely to stay dirty so do not
796 * mess with the page and do not clear the object flags. Returns TRUE if the
797 * page should be flushed, and FALSE otherwise.
798 */
799static boolean_t
800vm_object_page_remove_write(vm_page_t p, int flags, boolean_t *clearobjflags)
801{
802
803 /*
804 * If we have been asked to skip nosync pages and this is a
805 * nosync page, skip it. Note that the object flags were not
806 * cleared in this case so we do not have to set them.
807 */
808 if ((flags & OBJPC_NOSYNC) != 0 && (p->oflags & VPO_NOSYNC) != 0) {
809 *clearobjflags = FALSE;
810 return (FALSE);
811 } else {
812 pmap_remove_write(p);
813 return (p->dirty != 0);
814 }
815}
816
817/*
818 * vm_object_page_clean
819 *
820 * Clean all dirty pages in the specified range of object. Leaves page
821 * on whatever queue it is currently on. If NOSYNC is set then do not
822 * write out pages with VPO_NOSYNC set (originally comes from MAP_NOSYNC),
823 * leaving the object dirty.
824 *
825 * When stuffing pages asynchronously, allow clustering. XXX we need a
826 * synchronous clustering mode implementation.
827 *
828 * Odd semantics: if start == end, we clean everything.
829 *
830 * The object must be locked.
831 *
832 * Returns FALSE if some page from the range was not written, as
833 * reported by the pager, and TRUE otherwise.
834 */
835boolean_t
836vm_object_page_clean(vm_object_t object, vm_ooffset_t start, vm_ooffset_t end,
837 int flags)
838{
839 vm_page_t np, p;
840 vm_pindex_t pi, tend, tstart;
841 int curgeneration, n, pagerflags;
842 boolean_t clearobjflags, eio, res;
843
844 VM_OBJECT_ASSERT_WLOCKED(object);
845
846 /*
847 * The OBJ_MIGHTBEDIRTY flag is only set for OBJT_VNODE
848 * objects. The check below prevents the function from
849 * operating on non-vnode objects.
850 */
851 if ((object->flags & OBJ_MIGHTBEDIRTY) == 0 ||
852 object->resident_page_count == 0)
853 return (TRUE);
854
855 pagerflags = (flags & (OBJPC_SYNC | OBJPC_INVAL)) != 0 ?
856 VM_PAGER_PUT_SYNC : VM_PAGER_CLUSTER_OK;
857 pagerflags |= (flags & OBJPC_INVAL) != 0 ? VM_PAGER_PUT_INVAL : 0;
858
859 tstart = OFF_TO_IDX(start);
860 tend = (end == 0) ? object->size : OFF_TO_IDX(end + PAGE_MASK);
861 clearobjflags = tstart == 0 && tend >= object->size;
862 res = TRUE;
863
864rescan:
865 curgeneration = object->generation;
866
867 for (p = vm_page_find_least(object, tstart); p != NULL; p = np) {
868 pi = p->pindex;
869 if (pi >= tend)
870 break;
871 np = TAILQ_NEXT(p, listq);
872 if (p->valid == 0)
873 continue;
874 if (vm_page_sleep_if_busy(p, TRUE, "vpcwai")) {
875 if (object->generation != curgeneration) {
876 if ((flags & OBJPC_SYNC) != 0)
877 goto rescan;
878 else
879 clearobjflags = FALSE;
880 }
881 np = vm_page_find_least(object, pi);
882 continue;
883 }
884 if (!vm_object_page_remove_write(p, flags, &clearobjflags))
885 continue;
886
887 n = vm_object_page_collect_flush(object, p, pagerflags,
888 flags, &clearobjflags, &eio);
889 if (eio) {
890 res = FALSE;
891 clearobjflags = FALSE;
892 }
893 if (object->generation != curgeneration) {
894 if ((flags & OBJPC_SYNC) != 0)
895 goto rescan;
896 else
897 clearobjflags = FALSE;
898 }
899
900 /*
901 * If the VOP_PUTPAGES() did a truncated write, so
902 * that even the first page of the run is not fully
903 * written, vm_pageout_flush() returns 0 as the run
904 * length. Since the condition that caused truncated
905 * write may be permanent, e.g. exhausted free space,
906 * accepting n == 0 would cause an infinite loop.
907 *
908 * Forwarding the iterator leaves the unwritten page
909 * behind, but there is not much we can do there if
910 * filesystem refuses to write it.
911 */
912 if (n == 0) {
913 n = 1;
914 clearobjflags = FALSE;
915 }
916 np = vm_page_find_least(object, pi + n);
917 }
918#if 0
919 VOP_FSYNC(vp, (pagerflags & VM_PAGER_PUT_SYNC) ? MNT_WAIT : 0);
920#endif
921
922 if (clearobjflags)
923 vm_object_clear_flag(object, OBJ_MIGHTBEDIRTY);
924 return (res);
925}
926
927static int
928vm_object_page_collect_flush(vm_object_t object, vm_page_t p, int pagerflags,
929 int flags, boolean_t *clearobjflags, boolean_t *eio)
930{
931 vm_page_t ma[vm_pageout_page_count], p_first, tp;
932 int count, i, mreq, runlen;
933
934 vm_page_lock_assert(p, MA_NOTOWNED);
935 VM_OBJECT_ASSERT_WLOCKED(object);
936
937 count = 1;
938 mreq = 0;
939
940 for (tp = p; count < vm_pageout_page_count; count++) {
941 tp = vm_page_next(tp);
942 if (tp == NULL || tp->busy != 0 || (tp->oflags & VPO_BUSY) != 0)
943 break;
944 if (!vm_object_page_remove_write(tp, flags, clearobjflags))
945 break;
946 }
947
948 for (p_first = p; count < vm_pageout_page_count; count++) {
949 tp = vm_page_prev(p_first);
950 if (tp == NULL || tp->busy != 0 || (tp->oflags & VPO_BUSY) != 0)
951 break;
952 if (!vm_object_page_remove_write(tp, flags, clearobjflags))
953 break;
954 p_first = tp;
955 mreq++;
956 }
957
958 for (tp = p_first, i = 0; i < count; tp = TAILQ_NEXT(tp, listq), i++)
959 ma[i] = tp;
960
961 vm_pageout_flush(ma, count, pagerflags, mreq, &runlen, eio);
962 return (runlen);
963}
964
965/*
966 * Note that there is absolutely no sense in writing out
967 * anonymous objects, so we track down the vnode object
968 * to write out.
969 * We invalidate (remove) all pages from the address space
970 * for semantic correctness.
971 *
972 * If the backing object is a device object with unmanaged pages, then any
973 * mappings to the specified range of pages must be removed before this
974 * function is called.
975 *
976 * Note: certain anonymous maps, such as MAP_NOSYNC maps,
977 * may start out with a NULL object.
978 */
979boolean_t
980vm_object_sync(vm_object_t object, vm_ooffset_t offset, vm_size_t size,
981 boolean_t syncio, boolean_t invalidate)
982{
983 vm_object_t backing_object;
984 struct vnode *vp;
985 struct mount *mp;
986 int error, flags, fsync_after;
987 boolean_t res;
988
989 if (object == NULL)
990 return (TRUE);
991 res = TRUE;
992 error = 0;
993 VM_OBJECT_WLOCK(object);
994 while ((backing_object = object->backing_object) != NULL) {
995 VM_OBJECT_WLOCK(backing_object);
996 offset += object->backing_object_offset;
997 VM_OBJECT_WUNLOCK(object);
998 object = backing_object;
999 if (object->size < OFF_TO_IDX(offset + size))
1000 size = IDX_TO_OFF(object->size) - offset;
1001 }
1002 /*
1003 * Flush pages if writing is allowed, invalidate them
1004 * if invalidation requested. Pages undergoing I/O
1005 * will be ignored by vm_object_page_remove().
1006 *
1007 * We cannot lock the vnode and then wait for paging
1008 * to complete without deadlocking against vm_fault.
1009 * Instead we simply call vm_object_page_remove() and
1010 * allow it to block internally on a page-by-page
1011 * basis when it encounters pages undergoing async
1012 * I/O.
1013 */
1014 if (object->type == OBJT_VNODE &&
1015 (object->flags & OBJ_MIGHTBEDIRTY) != 0) {
1016 vp = object->handle;
1017 VM_OBJECT_WUNLOCK(object);
1018 (void) vn_start_write(vp, &mp, V_WAIT);
1019 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
1020 if (syncio && !invalidate && offset == 0 &&
1021 OFF_TO_IDX(size) == object->size) {
1022 /*
1023 * If syncing the whole mapping of the file,
1024 * it is faster to schedule all the writes in
1025 * async mode, also allowing the clustering,
1026 * and then wait for i/o to complete.
1027 */
1028 flags = 0;
1029 fsync_after = TRUE;
1030 } else {
1031 flags = (syncio || invalidate) ? OBJPC_SYNC : 0;
1032 flags |= invalidate ? (OBJPC_SYNC | OBJPC_INVAL) : 0;
1033 fsync_after = FALSE;
1034 }
1035 VM_OBJECT_WLOCK(object);
1036 res = vm_object_page_clean(object, offset, offset + size,
1037 flags);
1038 VM_OBJECT_WUNLOCK(object);
1039 if (fsync_after)
1040 error = VOP_FSYNC(vp, MNT_WAIT, curthread);
1041 VOP_UNLOCK(vp, 0);
1042 vn_finished_write(mp);
1043 if (error != 0)
1044 res = FALSE;
1045 VM_OBJECT_WLOCK(object);
1046 }
1047 if ((object->type == OBJT_VNODE ||
1048 object->type == OBJT_DEVICE) && invalidate) {
1049 if (object->type == OBJT_DEVICE)
1050 /*
1051 * The option OBJPR_NOTMAPPED must be passed here
1052 * because vm_object_page_remove() cannot remove
1053 * unmanaged mappings.
1054 */
1055 flags = OBJPR_NOTMAPPED;
1056 else if (old_msync)
1057 flags = OBJPR_NOTWIRED;
1058 else
1059 flags = OBJPR_CLEANONLY | OBJPR_NOTWIRED;
1060 vm_object_page_remove(object, OFF_TO_IDX(offset),
1061 OFF_TO_IDX(offset + size + PAGE_MASK), flags);
1062 }
1063 VM_OBJECT_WUNLOCK(object);
1064 return (res);
1065}
1066
1067/*
1068 * vm_object_madvise:
1069 *
1070 * Implements the madvise function at the object/page level.
1071 *
1072 * MADV_WILLNEED (any object)
1073 *
1074 * Activate the specified pages if they are resident.
1075 *
1076 * MADV_DONTNEED (any object)
1077 *
1078 * Deactivate the specified pages if they are resident.
1079 *
1080 * MADV_FREE (OBJT_DEFAULT/OBJT_SWAP objects,
1081 * OBJ_ONEMAPPING only)
1082 *
1083 * Deactivate and clean the specified pages if they are
1084 * resident. This permits the process to reuse the pages
1085 * without faulting or the kernel to reclaim the pages
1086 * without I/O.
1087 */
1088void
1089vm_object_madvise(vm_object_t object, vm_pindex_t pindex, vm_pindex_t end,
1090 int advise)
1091{
1092 vm_pindex_t tpindex;
1093 vm_object_t backing_object, tobject;
1094 vm_page_t m;
1095
1096 if (object == NULL)
1097 return;
1098 VM_OBJECT_WLOCK(object);
1099 /*
1100 * Locate and adjust resident pages
1101 */
1102 for (; pindex < end; pindex += 1) {
1103relookup:
1104 tobject = object;
1105 tpindex = pindex;
1106shadowlookup:
1107 /*
1108 * MADV_FREE only operates on OBJT_DEFAULT or OBJT_SWAP pages
1109 * and those pages must be OBJ_ONEMAPPING.
1110 */
1111 if (advise == MADV_FREE) {
1112 if ((tobject->type != OBJT_DEFAULT &&
1113 tobject->type != OBJT_SWAP) ||
1114 (tobject->flags & OBJ_ONEMAPPING) == 0) {
1115 goto unlock_tobject;
1116 }
1117 } else if ((tobject->flags & OBJ_UNMANAGED) != 0)
1118 goto unlock_tobject;
1119 m = vm_page_lookup(tobject, tpindex);
1120 if (m == NULL && advise == MADV_WILLNEED) {
1121 /*
1122 * If the page is cached, reactivate it.
1123 */
1124 m = vm_page_alloc(tobject, tpindex, VM_ALLOC_IFCACHED |
1125 VM_ALLOC_NOBUSY);
1126 }
1127 if (m == NULL) {
1128 /*
1129 * There may be swap even if there is no backing page
1130 */
1131 if (advise == MADV_FREE && tobject->type == OBJT_SWAP)
1132 swap_pager_freespace(tobject, tpindex, 1);
1133 /*
1134 * next object
1135 */
1136 backing_object = tobject->backing_object;
1137 if (backing_object == NULL)
1138 goto unlock_tobject;
1139 VM_OBJECT_WLOCK(backing_object);
1140 tpindex += OFF_TO_IDX(tobject->backing_object_offset);
1141 if (tobject != object)
1142 VM_OBJECT_WUNLOCK(tobject);
1143 tobject = backing_object;
1144 goto shadowlookup;
1145 } else if (m->valid != VM_PAGE_BITS_ALL)
1146 goto unlock_tobject;
1147 /*
1148 * If the page is not in a normal state, skip it.
1149 */
1150 vm_page_lock(m);
1151 if (m->hold_count != 0 || m->wire_count != 0) {
1152 vm_page_unlock(m);
1153 goto unlock_tobject;
1154 }
1155 KASSERT((m->flags & PG_FICTITIOUS) == 0,
1156 ("vm_object_madvise: page %p is fictitious", m));
1157 KASSERT((m->oflags & VPO_UNMANAGED) == 0,
1158 ("vm_object_madvise: page %p is not managed", m));
1159 if ((m->oflags & VPO_BUSY) || m->busy) {
1160 if (advise == MADV_WILLNEED) {
1161 /*
1162 * Reference the page before unlocking and
1163 * sleeping so that the page daemon is less
1164 * likely to reclaim it.
1165 */
1166 vm_page_aflag_set(m, PGA_REFERENCED);
1167 }
1168 vm_page_unlock(m);
1169 if (object != tobject)
1170 VM_OBJECT_WUNLOCK(object);
1171 m->oflags |= VPO_WANTED;
1172 VM_OBJECT_SLEEP(tobject, m, PDROP | PVM, "madvpo", 0);
1173 VM_OBJECT_WLOCK(object);
1174 goto relookup;
1175 }
1176 if (advise == MADV_WILLNEED) {
1177 vm_page_activate(m);
1178 } else {
1179 vm_page_advise(m, advise);
1180 }
1181 vm_page_unlock(m);
1182 if (advise == MADV_FREE && tobject->type == OBJT_SWAP)
1183 swap_pager_freespace(tobject, tpindex, 1);
1184unlock_tobject:
1185 if (tobject != object)
1186 VM_OBJECT_WUNLOCK(tobject);
1187 }
1188 VM_OBJECT_WUNLOCK(object);
1189}
1190
1191/*
1192 * vm_object_shadow:
1193 *
1194 * Create a new object which is backed by the
1195 * specified existing object range. The source
1196 * object reference is deallocated.
1197 *
1198 * The new object and offset into that object
1199 * are returned in the source parameters.
1200 */
1201void
1202vm_object_shadow(
1203 vm_object_t *object, /* IN/OUT */
1204 vm_ooffset_t *offset, /* IN/OUT */
1205 vm_size_t length)
1206{
1207 vm_object_t source;
1208 vm_object_t result;
1209
1210 source = *object;
1211
1212 /*
1213 * Don't create the new object if the old object isn't shared.
1214 */
1215 if (source != NULL) {
1216 VM_OBJECT_WLOCK(source);
1217 if (source->ref_count == 1 &&
1218 source->handle == NULL &&
1219 (source->type == OBJT_DEFAULT ||
1220 source->type == OBJT_SWAP)) {
1221 VM_OBJECT_WUNLOCK(source);
1222 return;
1223 }
1224 VM_OBJECT_WUNLOCK(source);
1225 }
1226
1227 /*
1228 * Allocate a new object with the given length.
1229 */
1230 result = vm_object_allocate(OBJT_DEFAULT, atop(length));
1231
1232 /*
1233 * The new object shadows the source object, adding a reference to it.
1234 * Our caller changes his reference to point to the new object,
1235 * removing a reference to the source object. Net result: no change
1236 * of reference count.
1237 *
1238 * Try to optimize the result object's page color when shadowing
1239 * in order to maintain page coloring consistency in the combined
1240 * shadowed object.
1241 */
1242 result->backing_object = source;
1243 /*
1244 * Store the offset into the source object, and fix up the offset into
1245 * the new object.
1246 */
1247 result->backing_object_offset = *offset;
1248 if (source != NULL) {
1249 VM_OBJECT_WLOCK(source);
1250 LIST_INSERT_HEAD(&source->shadow_head, result, shadow_list);
1251 source->shadow_count++;
1252#if VM_NRESERVLEVEL > 0
1253 result->flags |= source->flags & OBJ_COLORED;
1254 result->pg_color = (source->pg_color + OFF_TO_IDX(*offset)) &
1255 ((1 << (VM_NFREEORDER - 1)) - 1);
1256#endif
1257 VM_OBJECT_WUNLOCK(source);
1258 }
1259
1260
1261 /*
1262 * Return the new things
1263 */
1264 *offset = 0;
1265 *object = result;
1266}
1267
1268/*
1269 * vm_object_split:
1270 *
1271 * Split the pages in a map entry into a new object. This affords
1272 * easier removal of unused pages, and keeps object inheritance from
1273 * being a negative impact on memory usage.
1274 */
1275void
1276vm_object_split(vm_map_entry_t entry)
1277{
1278 vm_page_t m, m_next;
1279 vm_object_t orig_object, new_object, source;
1280 vm_pindex_t idx, offidxstart;
1281 vm_size_t size;
1282
1283 orig_object = entry->object.vm_object;
1284 if (orig_object->type != OBJT_DEFAULT && orig_object->type != OBJT_SWAP)
1285 return;
1286 if (orig_object->ref_count <= 1)
1287 return;
1288 VM_OBJECT_WUNLOCK(orig_object);
1289
1290 offidxstart = OFF_TO_IDX(entry->offset);
1291 size = atop(entry->end - entry->start);
1292
1293 /*
1294 * If swap_pager_copy() is later called, it will convert new_object
1295 * into a swap object.
1296 */
1297 new_object = vm_object_allocate(OBJT_DEFAULT, size);
1298
1299 /*
1300 * At this point, the new object is still private, so the order in
1301 * which the original and new objects are locked does not matter.
1302 */
1303 VM_OBJECT_WLOCK(new_object);
1304 VM_OBJECT_WLOCK(orig_object);
1305 source = orig_object->backing_object;
1306 if (source != NULL) {
1307 VM_OBJECT_WLOCK(source);
1308 if ((source->flags & OBJ_DEAD) != 0) {
1309 VM_OBJECT_WUNLOCK(source);
1310 VM_OBJECT_WUNLOCK(orig_object);
1311 VM_OBJECT_WUNLOCK(new_object);
1312 vm_object_deallocate(new_object);
1313 VM_OBJECT_WLOCK(orig_object);
1314 return;
1315 }
1316 LIST_INSERT_HEAD(&source->shadow_head,
1317 new_object, shadow_list);
1318 source->shadow_count++;
1319 vm_object_reference_locked(source); /* for new_object */
1320 vm_object_clear_flag(source, OBJ_ONEMAPPING);
1321 VM_OBJECT_WUNLOCK(source);
1322 new_object->backing_object_offset =
1323 orig_object->backing_object_offset + entry->offset;
1324 new_object->backing_object = source;
1325 }
1326 if (orig_object->cred != NULL) {
1327 new_object->cred = orig_object->cred;
1328 crhold(orig_object->cred);
1329 new_object->charge = ptoa(size);
1330 KASSERT(orig_object->charge >= ptoa(size),
1331 ("orig_object->charge < 0"));
1332 orig_object->charge -= ptoa(size);
1333 }
1334retry:
1335 m = vm_page_find_least(orig_object, offidxstart);
1336 for (; m != NULL && (idx = m->pindex - offidxstart) < size;
1337 m = m_next) {
1338 m_next = TAILQ_NEXT(m, listq);
1339
1340 /*
1341 * We must wait for pending I/O to complete before we can
1342 * rename the page.
1343 *
1344 * We do not have to VM_PROT_NONE the page as mappings should
1345 * not be changed by this operation.
1346 */
1347 if ((m->oflags & VPO_BUSY) || m->busy) {
1348 VM_OBJECT_WUNLOCK(new_object);
1349 m->oflags |= VPO_WANTED;
1350 VM_OBJECT_SLEEP(orig_object, m, PVM, "spltwt", 0);
1351 VM_OBJECT_WLOCK(new_object);
1352 goto retry;
1353 }
1354#if VM_NRESERVLEVEL > 0
1355 /*
1356 * If some of the reservation's allocated pages remain with
1357 * the original object, then transferring the reservation to
1358 * the new object is neither particularly beneficial nor
1359 * particularly harmful as compared to leaving the reservation
1360 * with the original object. If, however, all of the
1361 * reservation's allocated pages are transferred to the new
1362 * object, then transferring the reservation is typically
1363 * beneficial. Determining which of these two cases applies
1364 * would be more costly than unconditionally renaming the
1365 * reservation.
1366 */
1367 vm_reserv_rename(m, new_object, orig_object, offidxstart);
1368#endif
1369 vm_page_lock(m);
1370 vm_page_rename(m, new_object, idx);
1371 vm_page_unlock(m);
1372 /* page automatically made dirty by rename and cache handled */
1373 if (orig_object->type == OBJT_SWAP)
1374 vm_page_busy(m);
1375 }
1376 if (orig_object->type == OBJT_SWAP) {
1377 /*
1378 * swap_pager_copy() can sleep, in which case the orig_object's
1379 * and new_object's locks are released and reacquired.
1380 */
1381 swap_pager_copy(orig_object, new_object, offidxstart, 0);
1382 TAILQ_FOREACH(m, &new_object->memq, listq)
1383 vm_page_wakeup(m);
1384
1385 /*
1386 * Transfer any cached pages from orig_object to new_object.
1387 * If swap_pager_copy() found swapped out pages within the
1388 * specified range of orig_object, then it changed
1389 * new_object's type to OBJT_SWAP when it transferred those
1390 * pages to new_object. Otherwise, new_object's type
1391 * should still be OBJT_DEFAULT and orig_object should not
1392 * contain any cached pages within the specified range.
1393 */
1394 if (__predict_false(!vm_object_cache_is_empty(orig_object)))
1395 vm_page_cache_transfer(orig_object, offidxstart,
1396 new_object);
1397 }
1398 VM_OBJECT_WUNLOCK(orig_object);
1399 VM_OBJECT_WUNLOCK(new_object);
1400 entry->object.vm_object = new_object;
1401 entry->offset = 0LL;
1402 vm_object_deallocate(orig_object);
1403 VM_OBJECT_WLOCK(new_object);
1404}
1405
1406#define OBSC_TEST_ALL_SHADOWED 0x0001
1407#define OBSC_COLLAPSE_NOWAIT 0x0002
1408#define OBSC_COLLAPSE_WAIT 0x0004
1409
1410static int
1411vm_object_backing_scan(vm_object_t object, int op)
1412{
1413 int r = 1;
1414 vm_page_t p;
1415 vm_object_t backing_object;
1416 vm_pindex_t backing_offset_index;
1417
1418 VM_OBJECT_ASSERT_WLOCKED(object);
1419 VM_OBJECT_ASSERT_WLOCKED(object->backing_object);
1420
1421 backing_object = object->backing_object;
1422 backing_offset_index = OFF_TO_IDX(object->backing_object_offset);
1423
1424 /*
1425 * Initial conditions
1426 */
1427 if (op & OBSC_TEST_ALL_SHADOWED) {
1428 /*
1429 * We do not want to have to test for the existence of cache
1430 * or swap pages in the backing object. XXX but with the
1431 * new swapper this would be pretty easy to do.
1432 *
1433 * XXX what about anonymous MAP_SHARED memory that hasn't
1434 * been ZFOD faulted yet? If we do not test for this, the
1435 * shadow test may succeed! XXX
1436 */
1437 if (backing_object->type != OBJT_DEFAULT) {
1438 return (0);
1439 }
1440 }
1441 if (op & OBSC_COLLAPSE_WAIT) {
1442 vm_object_set_flag(backing_object, OBJ_DEAD);
1443 }
1444
1445 /*
1446 * Our scan
1447 */
1448 p = TAILQ_FIRST(&backing_object->memq);
1449 while (p) {
1450 vm_page_t next = TAILQ_NEXT(p, listq);
1451 vm_pindex_t new_pindex = p->pindex - backing_offset_index;
1452
1453 if (op & OBSC_TEST_ALL_SHADOWED) {
1454 vm_page_t pp;
1455
1456 /*
1457 * Ignore pages outside the parent object's range
1458 * and outside the parent object's mapping of the
1459 * backing object.
1460 *
1461 * note that we do not busy the backing object's
1462 * page.
1463 */
1464 if (
1465 p->pindex < backing_offset_index ||
1466 new_pindex >= object->size
1467 ) {
1468 p = next;
1469 continue;
1470 }
1471
1472 /*
1473 * See if the parent has the page or if the parent's
1474 * object pager has the page. If the parent has the
1475 * page but the page is not valid, the parent's
1476 * object pager must have the page.
1477 *
1478 * If this fails, the parent does not completely shadow
1479 * the object and we might as well give up now.
1480 */
1481
1482 pp = vm_page_lookup(object, new_pindex);
1483 if (
1484 (pp == NULL || pp->valid == 0) &&
1485 !vm_pager_has_page(object, new_pindex, NULL, NULL)
1486 ) {
1487 r = 0;
1488 break;
1489 }
1490 }
1491
1492 /*
1493 * Check for busy page
1494 */
1495 if (op & (OBSC_COLLAPSE_WAIT | OBSC_COLLAPSE_NOWAIT)) {
1496 vm_page_t pp;
1497
1498 if (op & OBSC_COLLAPSE_NOWAIT) {
1499 if ((p->oflags & VPO_BUSY) ||
1500 !p->valid ||
1501 p->busy) {
1502 p = next;
1503 continue;
1504 }
1505 } else if (op & OBSC_COLLAPSE_WAIT) {
1506 if ((p->oflags & VPO_BUSY) || p->busy) {
1507 VM_OBJECT_WUNLOCK(object);
1508 p->oflags |= VPO_WANTED;
1509 VM_OBJECT_SLEEP(backing_object, p,
1510 PDROP | PVM, "vmocol", 0);
1511 VM_OBJECT_WLOCK(object);
1512 VM_OBJECT_WLOCK(backing_object);
1513 /*
1514 * If we slept, anything could have
1515 * happened. Since the object is
1516 * marked dead, the backing offset
1517 * should not have changed so we
1518 * just restart our scan.
1519 */
1520 p = TAILQ_FIRST(&backing_object->memq);
1521 continue;
1522 }
1523 }
1524
1525 KASSERT(
1526 p->object == backing_object,
1527 ("vm_object_backing_scan: object mismatch")
1528 );
1529
1530 /*
1531 * Destroy any associated swap
1532 */
1533 if (backing_object->type == OBJT_SWAP) {
1534 swap_pager_freespace(
1535 backing_object,
1536 p->pindex,
1537 1
1538 );
1539 }
1540
1541 if (
1542 p->pindex < backing_offset_index ||
1543 new_pindex >= object->size
1544 ) {
1545 /*
1546 * Page is out of the parent object's range, we
1547 * can simply destroy it.
1548 */
1549 vm_page_lock(p);
1550 KASSERT(!pmap_page_is_mapped(p),
1551 ("freeing mapped page %p", p));
1552 if (p->wire_count == 0)
1553 vm_page_free(p);
1554 else
1555 vm_page_remove(p);
1556 vm_page_unlock(p);
1557 p = next;
1558 continue;
1559 }
1560
1561 pp = vm_page_lookup(object, new_pindex);
1562 if (
1563 (op & OBSC_COLLAPSE_NOWAIT) != 0 &&
1564 (pp != NULL && pp->valid == 0)
1565 ) {
1566 /*
1567 * The page in the parent is not (yet) valid.
1568 * We don't know anything about the state of
1569 * the original page. It might be mapped,
1570 * so we must avoid the next if here.
1571 *
1572 * This is due to a race in vm_fault() where
1573 * we must unbusy the original (backing_obj)
1574 * page before we can (re)lock the parent.
1575 * Hence we can get here.
1576 */
1577 p = next;
1578 continue;
1579 }
1580 if (
1581 pp != NULL ||
1582 vm_pager_has_page(object, new_pindex, NULL, NULL)
1583 ) {
1584 /*
1585 * page already exists in parent OR swap exists
1586 * for this location in the parent. Destroy
1587 * the original page from the backing object.
1588 *
1589 * Leave the parent's page alone
1590 */
1591 vm_page_lock(p);
1592 KASSERT(!pmap_page_is_mapped(p),
1593 ("freeing mapped page %p", p));
1594 if (p->wire_count == 0)
1595 vm_page_free(p);
1596 else
1597 vm_page_remove(p);
1598 vm_page_unlock(p);
1599 p = next;
1600 continue;
1601 }
1602
1603#if VM_NRESERVLEVEL > 0
1604 /*
1605 * Rename the reservation.
1606 */
1607 vm_reserv_rename(p, object, backing_object,
1608 backing_offset_index);
1609#endif
1610
1611 /*
1612 * Page does not exist in parent, rename the
1613 * page from the backing object to the main object.
1614 *
1615 * If the page was mapped to a process, it can remain
1616 * mapped through the rename.
1617 */
1618 vm_page_lock(p);
1619 vm_page_rename(p, object, new_pindex);
1620 vm_page_unlock(p);
1621 /* page automatically made dirty by rename */
1622 }
1623 p = next;
1624 }
1625 return (r);
1626}
1627
1628
1629/*
1630 * this version of collapse allows the operation to occur earlier and
1631 * when paging_in_progress is true for an object... This is not a complete
1632 * operation, but should plug 99.9% of the rest of the leaks.
1633 */
1634static void
1635vm_object_qcollapse(vm_object_t object)
1636{
1637 vm_object_t backing_object = object->backing_object;
1638
1639 VM_OBJECT_ASSERT_WLOCKED(object);
1640 VM_OBJECT_ASSERT_WLOCKED(backing_object);
1641
1642 if (backing_object->ref_count != 1)
1643 return;
1644
1645 vm_object_backing_scan(object, OBSC_COLLAPSE_NOWAIT);
1646}
1647
1648/*
1649 * vm_object_collapse:
1650 *
1651 * Collapse an object with the object backing it.
1652 * Pages in the backing object are moved into the
1653 * parent, and the backing object is deallocated.
1654 */
1655void
1656vm_object_collapse(vm_object_t object)
1657{
1658 VM_OBJECT_ASSERT_WLOCKED(object);
1659
1660 while (TRUE) {
1661 vm_object_t backing_object;
1662
1663 /*
1664 * Verify that the conditions are right for collapse:
1665 *
1666 * The object exists and the backing object exists.
1667 */
1668 if ((backing_object = object->backing_object) == NULL)
1669 break;
1670
1671 /*
1672 * we check the backing object first, because it is most likely
1673 * not collapsable.
1674 */
1675 VM_OBJECT_WLOCK(backing_object);
1676 if (backing_object->handle != NULL ||
1677 (backing_object->type != OBJT_DEFAULT &&
1678 backing_object->type != OBJT_SWAP) ||
1679 (backing_object->flags & OBJ_DEAD) ||
1680 object->handle != NULL ||
1681 (object->type != OBJT_DEFAULT &&
1682 object->type != OBJT_SWAP) ||
1683 (object->flags & OBJ_DEAD)) {
1684 VM_OBJECT_WUNLOCK(backing_object);
1685 break;
1686 }
1687
1688 if (
1689 object->paging_in_progress != 0 ||
1690 backing_object->paging_in_progress != 0
1691 ) {
1692 vm_object_qcollapse(object);
1693 VM_OBJECT_WUNLOCK(backing_object);
1694 break;
1695 }
1696 /*
1697 * We know that we can either collapse the backing object (if
1698 * the parent is the only reference to it) or (perhaps) have
1699 * the parent bypass the object if the parent happens to shadow
1700 * all the resident pages in the entire backing object.
1701 *
1702 * This is ignoring pager-backed pages such as swap pages.
1703 * vm_object_backing_scan fails the shadowing test in this
1704 * case.
1705 */
1706 if (backing_object->ref_count == 1) {
1707 /*
1708 * If there is exactly one reference to the backing
1709 * object, we can collapse it into the parent.
1710 */
1711 vm_object_backing_scan(object, OBSC_COLLAPSE_WAIT);
1712
1713#if VM_NRESERVLEVEL > 0
1714 /*
1715 * Break any reservations from backing_object.
1716 */
1717 if (__predict_false(!LIST_EMPTY(&backing_object->rvq)))
1718 vm_reserv_break_all(backing_object);
1719#endif
1720
1721 /*
1722 * Move the pager from backing_object to object.
1723 */
1724 if (backing_object->type == OBJT_SWAP) {
1725 /*
1726 * swap_pager_copy() can sleep, in which case
1727 * the backing_object's and object's locks are
1728 * released and reacquired.
1729 * Since swap_pager_copy() is being asked to
1730 * destroy the source, it will change the
1731 * backing_object's type to OBJT_DEFAULT.
1732 */
1733 swap_pager_copy(
1734 backing_object,
1735 object,
1736 OFF_TO_IDX(object->backing_object_offset), TRUE);
1737
1738 /*
1739 * Free any cached pages from backing_object.
1740 */
1741 if (__predict_false(
1742 !vm_object_cache_is_empty(backing_object)))
1743 vm_page_cache_free(backing_object, 0, 0);
1744 }
1745 /*
1746 * Object now shadows whatever backing_object did.
1747 * Note that the reference to
1748 * backing_object->backing_object moves from within
1749 * backing_object to within object.
1750 */
1751 LIST_REMOVE(object, shadow_list);
1752 backing_object->shadow_count--;
1753 if (backing_object->backing_object) {
1754 VM_OBJECT_WLOCK(backing_object->backing_object);
1755 LIST_REMOVE(backing_object, shadow_list);
1756 LIST_INSERT_HEAD(
1757 &backing_object->backing_object->shadow_head,
1758 object, shadow_list);
1759 /*
1760 * The shadow_count has not changed.
1761 */
1762 VM_OBJECT_WUNLOCK(backing_object->backing_object);
1763 }
1764 object->backing_object = backing_object->backing_object;
1765 object->backing_object_offset +=
1766 backing_object->backing_object_offset;
1767
1768 /*
1769 * Discard backing_object.
1770 *
1771 * Since the backing object has no pages, no pager left,
1772 * and no object references within it, all that is
1773 * necessary is to dispose of it.
1774 */
1775 KASSERT(backing_object->ref_count == 1, (
1776"backing_object %p was somehow re-referenced during collapse!",
1777 backing_object));
1778 VM_OBJECT_WUNLOCK(backing_object);
1779 vm_object_destroy(backing_object);
1780
1781 object_collapses++;
1782 } else {
1783 vm_object_t new_backing_object;
1784
1785 /*
1786 * If we do not entirely shadow the backing object,
1787 * there is nothing we can do so we give up.
1788 */
1789 if (object->resident_page_count != object->size &&
1790 vm_object_backing_scan(object,
1791 OBSC_TEST_ALL_SHADOWED) == 0) {
1792 VM_OBJECT_WUNLOCK(backing_object);
1793 break;
1794 }
1795
1796 /*
1797 * Make the parent shadow the next object in the
1798 * chain. Deallocating backing_object will not remove
1799 * it, since its reference count is at least 2.
1800 */
1801 LIST_REMOVE(object, shadow_list);
1802 backing_object->shadow_count--;
1803
1804 new_backing_object = backing_object->backing_object;
1805 if ((object->backing_object = new_backing_object) != NULL) {
1806 VM_OBJECT_WLOCK(new_backing_object);
1807 LIST_INSERT_HEAD(
1808 &new_backing_object->shadow_head,
1809 object,
1810 shadow_list
1811 );
1812 new_backing_object->shadow_count++;
1813 vm_object_reference_locked(new_backing_object);
1814 VM_OBJECT_WUNLOCK(new_backing_object);
1815 object->backing_object_offset +=
1816 backing_object->backing_object_offset;
1817 }
1818
1819 /*
1820 * Drop the reference count on backing_object. Since
1821 * its ref_count was at least 2, it will not vanish.
1822 */
1823 backing_object->ref_count--;
1824 VM_OBJECT_WUNLOCK(backing_object);
1825 object_bypasses++;
1826 }
1827
1828 /*
1829 * Try again with this object's new backing object.
1830 */
1831 }
1832}
1833
1834/*
1835 * vm_object_page_remove:
1836 *
1837 * For the given object, either frees or invalidates each of the
1838 * specified pages. In general, a page is freed. However, if a page is
1839 * wired for any reason other than the existence of a managed, wired
1840 * mapping, then it may be invalidated but not removed from the object.
1841 * Pages are specified by the given range ["start", "end") and the option
1842 * OBJPR_CLEANONLY. As a special case, if "end" is zero, then the range
1843 * extends from "start" to the end of the object. If the option
1844 * OBJPR_CLEANONLY is specified, then only the non-dirty pages within the
1845 * specified range are affected. If the option OBJPR_NOTMAPPED is
1846 * specified, then the pages within the specified range must have no
1847 * mappings. Otherwise, if this option is not specified, any mappings to
1848 * the specified pages are removed before the pages are freed or
1849 * invalidated.
1850 *
1851 * In general, this operation should only be performed on objects that
1852 * contain managed pages. There are, however, two exceptions. First, it
1853 * is performed on the kernel and kmem objects by vm_map_entry_delete().
1854 * Second, it is used by msync(..., MS_INVALIDATE) to invalidate device-
1855 * backed pages. In both of these cases, the option OBJPR_CLEANONLY must
1856 * not be specified and the option OBJPR_NOTMAPPED must be specified.
1857 *
1858 * The object must be locked.
1859 */
1860void
1861vm_object_page_remove(vm_object_t object, vm_pindex_t start, vm_pindex_t end,
1862 int options)
1863{
1864 vm_page_t p, next;
1865 int wirings;
1866
1867 VM_OBJECT_ASSERT_WLOCKED(object);
1868 KASSERT((object->flags & OBJ_UNMANAGED) == 0 ||
1869 (options & (OBJPR_CLEANONLY | OBJPR_NOTMAPPED)) == OBJPR_NOTMAPPED,
1870 ("vm_object_page_remove: illegal options for object %p", object));
1871 if (object->resident_page_count == 0)
1872 goto skipmemq;
1873 vm_object_pip_add(object, 1);
1874again:
1875 p = vm_page_find_least(object, start);
1876
1877 /*
1878 * Here, the variable "p" is either (1) the page with the least pindex
1879 * greater than or equal to the parameter "start" or (2) NULL.
1880 */
1881 for (; p != NULL && (p->pindex < end || end == 0); p = next) {
1882 next = TAILQ_NEXT(p, listq);
1883
1884 /*
1885 * If the page is wired for any reason besides the existence
1886 * of managed, wired mappings, then it cannot be freed. For
1887 * example, fictitious pages, which represent device memory,
1888 * are inherently wired and cannot be freed. They can,
1889 * however, be invalidated if the option OBJPR_CLEANONLY is
1890 * not specified.
1891 */
1892 vm_page_lock(p);
1893 if ((wirings = p->wire_count) != 0 &&
1894 (wirings = pmap_page_wired_mappings(p)) != p->wire_count) {
1895 if ((options & (OBJPR_NOTWIRED | OBJPR_NOTMAPPED)) ==
1896 0) {
1897 pmap_remove_all(p);
1898 /* Account for removal of wired mappings. */
1899 if (wirings != 0)
1900 p->wire_count -= wirings;
1901 }
1902 if ((options & OBJPR_CLEANONLY) == 0) {
1903 p->valid = 0;
1904 vm_page_undirty(p);
1905 }
1906 goto next;
1907 }
1908 if (vm_page_sleep_if_busy(p, TRUE, "vmopar"))
1909 goto again;
1910 KASSERT((p->flags & PG_FICTITIOUS) == 0,
1911 ("vm_object_page_remove: page %p is fictitious", p));
1912 if ((options & OBJPR_CLEANONLY) != 0 && p->valid != 0) {
1913 if ((options & OBJPR_NOTMAPPED) == 0)
1914 pmap_remove_write(p);
1915 if (p->dirty)
1916 goto next;
1917 }
1918 if ((options & OBJPR_NOTMAPPED) == 0) {
1919 if ((options & OBJPR_NOTWIRED) != 0 && wirings != 0)
1920 goto next;
1921 pmap_remove_all(p);
1922 /* Account for removal of wired mappings. */
1923 if (wirings != 0) {
1924 KASSERT(p->wire_count == wirings,
1925 ("inconsistent wire count %d %d %p",
1926 p->wire_count, wirings, p));
1927 p->wire_count = 0;
1928 atomic_subtract_int(&cnt.v_wire_count, 1);
1929 }
1930 }
1931 vm_page_free(p);
1932next:
1933 vm_page_unlock(p);
1934 }
1935 vm_object_pip_wakeup(object);
1936skipmemq:
1937 if (__predict_false(!vm_object_cache_is_empty(object)))
1938 vm_page_cache_free(object, start, end);
1939}
1940
1941/*
1942 * vm_object_page_cache:
1943 *
1944 * For the given object, attempt to move the specified clean
1945 * pages to the cache queue. If a page is wired for any reason,
1946 * then it will not be changed. Pages are specified by the given
1947 * range ["start", "end"). As a special case, if "end" is zero,
1948 * then the range extends from "start" to the end of the object.
1949 * Any mappings to the specified pages are removed before the
1950 * pages are moved to the cache queue.
1951 *
1952 * This operation should only be performed on objects that
1953 * contain non-fictitious, managed pages.
1954 *
1955 * The object must be locked.
1956 */
1957void
1958vm_object_page_cache(vm_object_t object, vm_pindex_t start, vm_pindex_t end)
1959{
1960 struct mtx *mtx, *new_mtx;
1961 vm_page_t p, next;
1962
1963 VM_OBJECT_ASSERT_WLOCKED(object);
1964 KASSERT((object->flags & (OBJ_FICTITIOUS | OBJ_UNMANAGED)) == 0,
1965 ("vm_object_page_cache: illegal object %p", object));
1966 if (object->resident_page_count == 0)
1967 return;
1968 p = vm_page_find_least(object, start);
1969
1970 /*
1971 * Here, the variable "p" is either (1) the page with the least pindex
1972 * greater than or equal to the parameter "start" or (2) NULL.
1973 */
1974 mtx = NULL;
1975 for (; p != NULL && (p->pindex < end || end == 0); p = next) {
1976 next = TAILQ_NEXT(p, listq);
1977
1978 /*
1979 * Avoid releasing and reacquiring the same page lock.
1980 */
1981 new_mtx = vm_page_lockptr(p);
1982 if (mtx != new_mtx) {
1983 if (mtx != NULL)
1984 mtx_unlock(mtx);
1985 mtx = new_mtx;
1986 mtx_lock(mtx);
1987 }
1988 vm_page_try_to_cache(p);
1989 }
1990 if (mtx != NULL)
1991 mtx_unlock(mtx);
1992}
1993
1994/*
1995 * Populate the specified range of the object with valid pages. Returns
1996 * TRUE if the range is successfully populated and FALSE otherwise.
1997 *
1998 * Note: This function should be optimized to pass a larger array of
1999 * pages to vm_pager_get_pages() before it is applied to a non-
2000 * OBJT_DEVICE object.
2001 *
2002 * The object must be locked.
2003 */
2004boolean_t
2005vm_object_populate(vm_object_t object, vm_pindex_t start, vm_pindex_t end)
2006{
2007 vm_page_t m, ma[1];
2008 vm_pindex_t pindex;
2009 int rv;
2010
2011 VM_OBJECT_ASSERT_WLOCKED(object);
2012 for (pindex = start; pindex < end; pindex++) {
2013 m = vm_page_grab(object, pindex, VM_ALLOC_NORMAL |
2014 VM_ALLOC_RETRY);
2015 if (m->valid != VM_PAGE_BITS_ALL) {
2016 ma[0] = m;
2017 rv = vm_pager_get_pages(object, ma, 1, 0);
2018 m = vm_page_lookup(object, pindex);
2019 if (m == NULL)
2020 break;
2021 if (rv != VM_PAGER_OK) {
2022 vm_page_lock(m);
2023 vm_page_free(m);
2024 vm_page_unlock(m);
2025 break;
2026 }
2027 }
2028 /*
2029 * Keep "m" busy because a subsequent iteration may unlock
2030 * the object.
2031 */
2032 }
2033 if (pindex > start) {
2034 m = vm_page_lookup(object, start);
2035 while (m != NULL && m->pindex < pindex) {
2036 vm_page_wakeup(m);
2037 m = TAILQ_NEXT(m, listq);
2038 }
2039 }
2040 return (pindex == end);
2041}
2042
2043/*
2044 * Routine: vm_object_coalesce
2045 * Function: Coalesces two objects backing up adjoining
2046 * regions of memory into a single object.
2047 *
2048 * returns TRUE if objects were combined.
2049 *
2050 * NOTE: Only works at the moment if the second object is NULL -
2051 * if it's not, which object do we lock first?
2052 *
2053 * Parameters:
2054 * prev_object First object to coalesce
2055 * prev_offset Offset into prev_object
2056 * prev_size Size of reference to prev_object
2057 * next_size Size of reference to the second object
2058 * reserved Indicator that extension region has
2059 * swap accounted for
2060 *
2061 * Conditions:
2062 * The object must *not* be locked.
2063 */
2064boolean_t
2065vm_object_coalesce(vm_object_t prev_object, vm_ooffset_t prev_offset,
2066 vm_size_t prev_size, vm_size_t next_size, boolean_t reserved)
2067{
2068 vm_pindex_t next_pindex;
2069
2070 if (prev_object == NULL)
2071 return (TRUE);
2072 VM_OBJECT_WLOCK(prev_object);
2073 if (prev_object->type != OBJT_DEFAULT &&
2074 prev_object->type != OBJT_SWAP) {
2075 VM_OBJECT_WUNLOCK(prev_object);
2076 return (FALSE);
2077 }
2078
2079 /*
2080 * Try to collapse the object first
2081 */
2082 vm_object_collapse(prev_object);
2083
2084 /*
2085 * Can't coalesce if: . more than one reference . paged out . shadows
2086 * another object . has a copy elsewhere (any of which mean that the
2087 * pages not mapped to prev_entry may be in use anyway)
2088 */
2089 if (prev_object->backing_object != NULL) {
2090 VM_OBJECT_WUNLOCK(prev_object);
2091 return (FALSE);
2092 }
2093
2094 prev_size >>= PAGE_SHIFT;
2095 next_size >>= PAGE_SHIFT;
2096 next_pindex = OFF_TO_IDX(prev_offset) + prev_size;
2097
2098 if ((prev_object->ref_count > 1) &&
2099 (prev_object->size != next_pindex)) {
2100 VM_OBJECT_WUNLOCK(prev_object);
2101 return (FALSE);
2102 }
2103
2104 /*
2105 * Account for the charge.
2106 */
2107 if (prev_object->cred != NULL) {
2108
2109 /*
2110 * If prev_object was charged, then this mapping,
2111 * althought not charged now, may become writable
2112 * later. Non-NULL cred in the object would prevent
2113 * swap reservation during enabling of the write
2114 * access, so reserve swap now. Failed reservation
2115 * cause allocation of the separate object for the map
2116 * entry, and swap reservation for this entry is
2117 * managed in appropriate time.
2118 */
2119 if (!reserved && !swap_reserve_by_cred(ptoa(next_size),
2120 prev_object->cred)) {
2121 return (FALSE);
2122 }
2123 prev_object->charge += ptoa(next_size);
2124 }
2125
2126 /*
2127 * Remove any pages that may still be in the object from a previous
2128 * deallocation.
2129 */
2130 if (next_pindex < prev_object->size) {
2131 vm_object_page_remove(prev_object, next_pindex, next_pindex +
2132 next_size, 0);
2133 if (prev_object->type == OBJT_SWAP)
2134 swap_pager_freespace(prev_object,
2135 next_pindex, next_size);
2136#if 0
2137 if (prev_object->cred != NULL) {
2138 KASSERT(prev_object->charge >=
2139 ptoa(prev_object->size - next_pindex),
2140 ("object %p overcharged 1 %jx %jx", prev_object,
2141 (uintmax_t)next_pindex, (uintmax_t)next_size));
2142 prev_object->charge -= ptoa(prev_object->size -
2143 next_pindex);
2144 }
2145#endif
2146 }
2147
2148 /*
2149 * Extend the object if necessary.
2150 */
2151 if (next_pindex + next_size > prev_object->size)
2152 prev_object->size = next_pindex + next_size;
2153
2154 VM_OBJECT_WUNLOCK(prev_object);
2155 return (TRUE);
2156}
2157
2158void
2159vm_object_set_writeable_dirty(vm_object_t object)
2160{
2161
2162 VM_OBJECT_ASSERT_WLOCKED(object);
2163 if (object->type != OBJT_VNODE)
2164 return;
2165 object->generation++;
2166 if ((object->flags & OBJ_MIGHTBEDIRTY) != 0)
2167 return;
2168 vm_object_set_flag(object, OBJ_MIGHTBEDIRTY);
2169}
2170
2171#include "opt_ddb.h"
2172#ifdef DDB
2173#include <sys/kernel.h>
2174
2175#include <sys/cons.h>
2176
2177#include <ddb/ddb.h>
2178
2179static int
2180_vm_object_in_map(vm_map_t map, vm_object_t object, vm_map_entry_t entry)
2181{
2182 vm_map_t tmpm;
2183 vm_map_entry_t tmpe;
2184 vm_object_t obj;
2185 int entcount;
2186
2187 if (map == 0)
2188 return 0;
2189
2190 if (entry == 0) {
2191 tmpe = map->header.next;
2192 entcount = map->nentries;
2193 while (entcount-- && (tmpe != &map->header)) {
2194 if (_vm_object_in_map(map, object, tmpe)) {
2195 return 1;
2196 }
2197 tmpe = tmpe->next;
2198 }
2199 } else if (entry->eflags & MAP_ENTRY_IS_SUB_MAP) {
2200 tmpm = entry->object.sub_map;
2201 tmpe = tmpm->header.next;
2202 entcount = tmpm->nentries;
2203 while (entcount-- && tmpe != &tmpm->header) {
2204 if (_vm_object_in_map(tmpm, object, tmpe)) {
2205 return 1;
2206 }
2207 tmpe = tmpe->next;
2208 }
2209 } else if ((obj = entry->object.vm_object) != NULL) {
2210 for (; obj; obj = obj->backing_object)
2211 if (obj == object) {
2212 return 1;
2213 }
2214 }
2215 return 0;
2216}
2217
2218static int
2219vm_object_in_map(vm_object_t object)
2220{
2221 struct proc *p;
2222
2223 /* sx_slock(&allproc_lock); */
2224 FOREACH_PROC_IN_SYSTEM(p) {
2225 if (!p->p_vmspace /* || (p->p_flag & (P_SYSTEM|P_WEXIT)) */)
2226 continue;
2227 if (_vm_object_in_map(&p->p_vmspace->vm_map, object, 0)) {
2228 /* sx_sunlock(&allproc_lock); */
2229 return 1;
2230 }
2231 }
2232 /* sx_sunlock(&allproc_lock); */
2233 if (_vm_object_in_map(kernel_map, object, 0))
2234 return 1;
2235 return 0;
2236}
2237
2238DB_SHOW_COMMAND(vmochk, vm_object_check)
2239{
2240 vm_object_t object;
2241
2242 /*
2243 * make sure that internal objs are in a map somewhere
2244 * and none have zero ref counts.
2245 */
2246 TAILQ_FOREACH(object, &vm_object_list, object_list) {
2247 if (object->handle == NULL &&
2248 (object->type == OBJT_DEFAULT || object->type == OBJT_SWAP)) {
2249 if (object->ref_count == 0) {
2250 db_printf("vmochk: internal obj has zero ref count: %ld\n",
2251 (long)object->size);
2252 }
2253 if (!vm_object_in_map(object)) {
2254 db_printf(
2255 "vmochk: internal obj is not in a map: "
2256 "ref: %d, size: %lu: 0x%lx, backing_object: %p\n",
2257 object->ref_count, (u_long)object->size,
2258 (u_long)object->size,
2259 (void *)object->backing_object);
2260 }
2261 }
2262 }
2263}
2264
2265/*
2266 * vm_object_print: [ debug ]
2267 */
2268DB_SHOW_COMMAND(object, vm_object_print_static)
2269{
2270 /* XXX convert args. */
2271 vm_object_t object = (vm_object_t)addr;
2272 boolean_t full = have_addr;
2273
2274 vm_page_t p;
2275
2276 /* XXX count is an (unused) arg. Avoid shadowing it. */
2277#define count was_count
2278
2279 int count;
2280
2281 if (object == NULL)
2282 return;
2283
2284 db_iprintf(
2285 "Object %p: type=%d, size=0x%jx, res=%d, ref=%d, flags=0x%x ruid %d charge %jx\n",
2286 object, (int)object->type, (uintmax_t)object->size,
2287 object->resident_page_count, object->ref_count, object->flags,
2288 object->cred ? object->cred->cr_ruid : -1, (uintmax_t)object->charge);
2289 db_iprintf(" sref=%d, backing_object(%d)=(%p)+0x%jx\n",
2290 object->shadow_count,
2291 object->backing_object ? object->backing_object->ref_count : 0,
2292 object->backing_object, (uintmax_t)object->backing_object_offset);
2293
2294 if (!full)
2295 return;
2296
2297 db_indent += 2;
2298 count = 0;
2299 TAILQ_FOREACH(p, &object->memq, listq) {
2300 if (count == 0)
2301 db_iprintf("memory:=");
2302 else if (count == 6) {
2303 db_printf("\n");
2304 db_iprintf(" ...");
2305 count = 0;
2306 } else
2307 db_printf(",");
2308 count++;
2309
2310 db_printf("(off=0x%jx,page=0x%jx)",
2311 (uintmax_t)p->pindex, (uintmax_t)VM_PAGE_TO_PHYS(p));
2312 }
2313 if (count != 0)
2314 db_printf("\n");
2315 db_indent -= 2;
2316}
2317
2318/* XXX. */
2319#undef count
2320
2321/* XXX need this non-static entry for calling from vm_map_print. */
2322void
2323vm_object_print(
2324 /* db_expr_t */ long addr,
2325 boolean_t have_addr,
2326 /* db_expr_t */ long count,
2327 char *modif)
2328{
2329 vm_object_print_static(addr, have_addr, count, modif);
2330}
2331
2332DB_SHOW_COMMAND(vmopag, vm_object_print_pages)
2333{
2334 vm_object_t object;
2335 vm_pindex_t fidx;
2336 vm_paddr_t pa;
2337 vm_page_t m, prev_m;
2338 int rcount, nl, c;
2339
2340 nl = 0;
2341 TAILQ_FOREACH(object, &vm_object_list, object_list) {
2342 db_printf("new object: %p\n", (void *)object);
2343 if (nl > 18) {
2344 c = cngetc();
2345 if (c != ' ')
2346 return;
2347 nl = 0;
2348 }
2349 nl++;
2350 rcount = 0;
2351 fidx = 0;
2352 pa = -1;
2353 TAILQ_FOREACH(m, &object->memq, listq) {
2354 if (m->pindex > 128)
2355 break;
2356 if ((prev_m = TAILQ_PREV(m, pglist, listq)) != NULL &&
2357 prev_m->pindex + 1 != m->pindex) {
2358 if (rcount) {
2359 db_printf(" index(%ld)run(%d)pa(0x%lx)\n",
2360 (long)fidx, rcount, (long)pa);
2361 if (nl > 18) {
2362 c = cngetc();
2363 if (c != ' ')
2364 return;
2365 nl = 0;
2366 }
2367 nl++;
2368 rcount = 0;
2369 }
2370 }
2371 if (rcount &&
2372 (VM_PAGE_TO_PHYS(m) == pa + rcount * PAGE_SIZE)) {
2373 ++rcount;
2374 continue;
2375 }
2376 if (rcount) {
2377 db_printf(" index(%ld)run(%d)pa(0x%lx)\n",
2378 (long)fidx, rcount, (long)pa);
2379 if (nl > 18) {
2380 c = cngetc();
2381 if (c != ' ')
2382 return;
2383 nl = 0;
2384 }
2385 nl++;
2386 }
2387 fidx = m->pindex;
2388 pa = VM_PAGE_TO_PHYS(m);
2389 rcount = 1;
2390 }
2391 if (rcount) {
2392 db_printf(" index(%ld)run(%d)pa(0x%lx)\n",
2393 (long)fidx, rcount, (long)pa);
2394 if (nl > 18) {
2395 c = cngetc();
2396 if (c != ' ')
2397 return;
2398 nl = 0;
2399 }
2400 nl++;
2401 }
2402 }
2403}
2404#endif /* DDB */