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 207531 2010-05-02 18:09:33Z alc $");
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/vnode.h>
82#include <sys/vmmeter.h>
83#include <sys/sx.h>
84
85#include <vm/vm.h>
86#include <vm/vm_param.h>
87#include <vm/pmap.h>
88#include <vm/vm_map.h>
89#include <vm/vm_object.h>
90#include <vm/vm_page.h>
91#include <vm/vm_pageout.h>
92#include <vm/vm_pager.h>
93#include <vm/swap_pager.h>
94#include <vm/vm_kern.h>
95#include <vm/vm_extern.h>
96#include <vm/vm_reserv.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, CTLFLAG_RW, &msync_flush_flags, 0,
109 "Enable sequential iteration optimization");
110
111static int old_msync;
112SYSCTL_INT(_vm, OID_AUTO, old_msync, CTLFLAG_RW, &old_msync, 0,
113 "Use old (insecure) msync behavior");
114
115static void vm_object_qcollapse(vm_object_t object);
116static int vm_object_page_collect_flush(vm_object_t object, vm_page_t p, int curgeneration, int pagerflags);
117static void vm_object_vndeallocate(vm_object_t object);
118
119/*
120 * Virtual memory objects maintain the actual data
121 * associated with allocated virtual memory. A given
122 * page of memory exists within exactly one object.
123 *
124 * An object is only deallocated when all "references"
125 * are given up. Only one "reference" to a given
126 * region of an object should be writeable.
127 *
128 * Associated with each object is a list of all resident
129 * memory pages belonging to that object; this list is
130 * maintained by the "vm_page" module, and locked by the object's
131 * lock.
132 *
133 * Each object also records a "pager" routine which is
134 * used to retrieve (and store) pages to the proper backing
135 * storage. In addition, objects may be backed by other
136 * objects from which they were virtual-copied.
137 *
138 * The only items within the object structure which are
139 * modified after time of creation are:
140 * reference count locked by object's lock
141 * pager routine locked by object's lock
142 *
143 */
144
145struct object_q vm_object_list;
146struct mtx vm_object_list_mtx; /* lock for object list and count */
147
148struct vm_object kernel_object_store;
149struct vm_object kmem_object_store;
150
151SYSCTL_NODE(_vm_stats, OID_AUTO, object, CTLFLAG_RD, 0, "VM object stats");
152
153static long object_collapses;
154SYSCTL_LONG(_vm_stats_object, OID_AUTO, collapses, CTLFLAG_RD,
155 &object_collapses, 0, "VM object collapses");
156
157static long object_bypasses;
158SYSCTL_LONG(_vm_stats_object, OID_AUTO, bypasses, CTLFLAG_RD,
159 &object_bypasses, 0, "VM object bypasses");
160
161static uma_zone_t obj_zone;
162
163static int vm_object_zinit(void *mem, int size, int flags);
164
165#ifdef INVARIANTS
166static void vm_object_zdtor(void *mem, int size, void *arg);
167
168static void
169vm_object_zdtor(void *mem, int size, void *arg)
170{
171 vm_object_t object;
172
173 object = (vm_object_t)mem;
174 KASSERT(TAILQ_EMPTY(&object->memq),
175 ("object %p has resident pages",
176 object));
177#if VM_NRESERVLEVEL > 0
178 KASSERT(LIST_EMPTY(&object->rvq),
179 ("object %p has reservations",
180 object));
181#endif
182 KASSERT(object->cache == NULL,
183 ("object %p has cached pages",
184 object));
185 KASSERT(object->paging_in_progress == 0,
186 ("object %p paging_in_progress = %d",
187 object, object->paging_in_progress));
188 KASSERT(object->resident_page_count == 0,
189 ("object %p resident_page_count = %d",
190 object, object->resident_page_count));
191 KASSERT(object->shadow_count == 0,
192 ("object %p shadow_count = %d",
193 object, object->shadow_count));
194}
195#endif
196
197static int
198vm_object_zinit(void *mem, int size, int flags)
199{
200 vm_object_t object;
201
202 object = (vm_object_t)mem;
203 bzero(&object->mtx, sizeof(object->mtx));
204 VM_OBJECT_LOCK_INIT(object, "standard object");
205
206 /* These are true for any object that has been freed */
207 object->paging_in_progress = 0;
208 object->resident_page_count = 0;
209 object->shadow_count = 0;
210 return (0);
211}
212
213void
214_vm_object_allocate(objtype_t type, vm_pindex_t size, vm_object_t object)
215{
216
217 TAILQ_INIT(&object->memq);
218 LIST_INIT(&object->shadow_head);
219
220 object->root = NULL;
221 object->type = type;
222 object->size = size;
223 object->generation = 1;
224 object->ref_count = 1;
225 object->memattr = VM_MEMATTR_DEFAULT;
226 object->flags = 0;
227 object->uip = NULL;
228 object->charge = 0;
229 if ((object->type == OBJT_DEFAULT) || (object->type == OBJT_SWAP))
230 object->flags = OBJ_ONEMAPPING;
231 object->pg_color = 0;
232 object->handle = NULL;
233 object->backing_object = NULL;
234 object->backing_object_offset = (vm_ooffset_t) 0;
235#if VM_NRESERVLEVEL > 0
236 LIST_INIT(&object->rvq);
237#endif
238 object->cache = NULL;
239
240 mtx_lock(&vm_object_list_mtx);
241 TAILQ_INSERT_TAIL(&vm_object_list, object, object_list);
242 mtx_unlock(&vm_object_list_mtx);
243}
244
245/*
246 * vm_object_init:
247 *
248 * Initialize the VM objects module.
249 */
250void
251vm_object_init(void)
252{
253 TAILQ_INIT(&vm_object_list);
254 mtx_init(&vm_object_list_mtx, "vm object_list", NULL, MTX_DEF);
255
256 VM_OBJECT_LOCK_INIT(&kernel_object_store, "kernel object");
257 _vm_object_allocate(OBJT_PHYS, OFF_TO_IDX(VM_MAX_KERNEL_ADDRESS - VM_MIN_KERNEL_ADDRESS),
258 kernel_object);
259#if VM_NRESERVLEVEL > 0
260 kernel_object->flags |= OBJ_COLORED;
261 kernel_object->pg_color = (u_short)atop(VM_MIN_KERNEL_ADDRESS);
262#endif
263
264 VM_OBJECT_LOCK_INIT(&kmem_object_store, "kmem object");
265 _vm_object_allocate(OBJT_PHYS, OFF_TO_IDX(VM_MAX_KERNEL_ADDRESS - VM_MIN_KERNEL_ADDRESS),
266 kmem_object);
267#if VM_NRESERVLEVEL > 0
268 kmem_object->flags |= OBJ_COLORED;
269 kmem_object->pg_color = (u_short)atop(VM_MIN_KERNEL_ADDRESS);
270#endif
271
272 /*
273 * The lock portion of struct vm_object must be type stable due
274 * to vm_pageout_fallback_object_lock locking a vm object
275 * without holding any references to it.
276 */
277 obj_zone = uma_zcreate("VM OBJECT", sizeof (struct vm_object), NULL,
278#ifdef INVARIANTS
279 vm_object_zdtor,
280#else
281 NULL,
282#endif
283 vm_object_zinit, NULL, UMA_ALIGN_PTR, UMA_ZONE_VM|UMA_ZONE_NOFREE);
284}
285
286void
287vm_object_clear_flag(vm_object_t object, u_short bits)
288{
289
290 VM_OBJECT_LOCK_ASSERT(object, MA_OWNED);
291 object->flags &= ~bits;
292}
293
294/*
295 * Sets the default memory attribute for the specified object. Pages
296 * that are allocated to this object are by default assigned this memory
297 * attribute.
298 *
299 * Presently, this function must be called before any pages are allocated
300 * to the object. In the future, this requirement may be relaxed for
301 * "default" and "swap" objects.
302 */
303int
304vm_object_set_memattr(vm_object_t object, vm_memattr_t memattr)
305{
306
307 VM_OBJECT_LOCK_ASSERT(object, MA_OWNED);
308 switch (object->type) {
309 case OBJT_DEFAULT:
310 case OBJT_DEVICE:
311 case OBJT_PHYS:
312 case OBJT_SG:
313 case OBJT_SWAP:
314 case OBJT_VNODE:
315 if (!TAILQ_EMPTY(&object->memq))
316 return (KERN_FAILURE);
317 break;
318 case OBJT_DEAD:
319 return (KERN_INVALID_ARGUMENT);
320 }
321 object->memattr = memattr;
322 return (KERN_SUCCESS);
323}
324
325void
326vm_object_pip_add(vm_object_t object, short i)
327{
328
329 VM_OBJECT_LOCK_ASSERT(object, MA_OWNED);
330 object->paging_in_progress += i;
331}
332
333void
334vm_object_pip_subtract(vm_object_t object, short i)
335{
336
337 VM_OBJECT_LOCK_ASSERT(object, MA_OWNED);
338 object->paging_in_progress -= i;
339}
340
341void
342vm_object_pip_wakeup(vm_object_t object)
343{
344
345 VM_OBJECT_LOCK_ASSERT(object, MA_OWNED);
346 object->paging_in_progress--;
347 if ((object->flags & OBJ_PIPWNT) && object->paging_in_progress == 0) {
348 vm_object_clear_flag(object, OBJ_PIPWNT);
349 wakeup(object);
350 }
351}
352
353void
354vm_object_pip_wakeupn(vm_object_t object, short i)
355{
356
357 VM_OBJECT_LOCK_ASSERT(object, MA_OWNED);
358 if (i)
359 object->paging_in_progress -= i;
360 if ((object->flags & OBJ_PIPWNT) && object->paging_in_progress == 0) {
361 vm_object_clear_flag(object, OBJ_PIPWNT);
362 wakeup(object);
363 }
364}
365
366void
367vm_object_pip_wait(vm_object_t object, char *waitid)
368{
369
370 VM_OBJECT_LOCK_ASSERT(object, MA_OWNED);
371 while (object->paging_in_progress) {
372 object->flags |= OBJ_PIPWNT;
373 msleep(object, VM_OBJECT_MTX(object), PVM, waitid, 0);
374 }
375}
376
377/*
378 * vm_object_allocate:
379 *
380 * Returns a new object with the given size.
381 */
382vm_object_t
383vm_object_allocate(objtype_t type, vm_pindex_t size)
384{
385 vm_object_t object;
386
387 object = (vm_object_t)uma_zalloc(obj_zone, M_WAITOK);
388 _vm_object_allocate(type, size, object);
389 return (object);
390}
391
392
393/*
394 * vm_object_reference:
395 *
396 * Gets another reference to the given object. Note: OBJ_DEAD
397 * objects can be referenced during final cleaning.
398 */
399void
400vm_object_reference(vm_object_t object)
401{
402 if (object == NULL)
403 return;
404 VM_OBJECT_LOCK(object);
405 vm_object_reference_locked(object);
406 VM_OBJECT_UNLOCK(object);
407}
408
409/*
410 * vm_object_reference_locked:
411 *
412 * Gets another reference to the given object.
413 *
414 * The object must be locked.
415 */
416void
417vm_object_reference_locked(vm_object_t object)
418{
419 struct vnode *vp;
420
421 VM_OBJECT_LOCK_ASSERT(object, MA_OWNED);
422 object->ref_count++;
423 if (object->type == OBJT_VNODE) {
424 vp = object->handle;
425 vref(vp);
426 }
427}
428
429/*
430 * Handle deallocating an object of type OBJT_VNODE.
431 */
432static void
433vm_object_vndeallocate(vm_object_t object)
434{
435 struct vnode *vp = (struct vnode *) object->handle;
436
437 VFS_ASSERT_GIANT(vp->v_mount);
438 VM_OBJECT_LOCK_ASSERT(object, MA_OWNED);
439 KASSERT(object->type == OBJT_VNODE,
440 ("vm_object_vndeallocate: not a vnode object"));
441 KASSERT(vp != NULL, ("vm_object_vndeallocate: missing vp"));
442#ifdef INVARIANTS
443 if (object->ref_count == 0) {
444 vprint("vm_object_vndeallocate", vp);
445 panic("vm_object_vndeallocate: bad object reference count");
446 }
447#endif
448
449 object->ref_count--;
450 if (object->ref_count == 0) {
451 mp_fixme("Unlocked vflag access.");
452 vp->v_vflag &= ~VV_TEXT;
453 }
454 VM_OBJECT_UNLOCK(object);
455 /*
456 * vrele may need a vop lock
457 */
458 vrele(vp);
459}
460
461/*
462 * vm_object_deallocate:
463 *
464 * Release a reference to the specified object,
465 * gained either through a vm_object_allocate
466 * or a vm_object_reference call. When all references
467 * are gone, storage associated with this object
468 * may be relinquished.
469 *
470 * No object may be locked.
471 */
472void
473vm_object_deallocate(vm_object_t object)
474{
475 vm_object_t temp;
476
477 while (object != NULL) {
478 int vfslocked;
479
480 vfslocked = 0;
481 restart:
482 VM_OBJECT_LOCK(object);
483 if (object->type == OBJT_VNODE) {
484 struct vnode *vp = (struct vnode *) object->handle;
485
486 /*
487 * Conditionally acquire Giant for a vnode-backed
488 * object. We have to be careful since the type of
489 * a vnode object can change while the object is
490 * unlocked.
491 */
492 if (VFS_NEEDSGIANT(vp->v_mount) && !vfslocked) {
493 vfslocked = 1;
494 if (!mtx_trylock(&Giant)) {
495 VM_OBJECT_UNLOCK(object);
496 mtx_lock(&Giant);
497 goto restart;
498 }
499 }
500 vm_object_vndeallocate(object);
501 VFS_UNLOCK_GIANT(vfslocked);
502 return;
503 } else
504 /*
505 * This is to handle the case that the object
506 * changed type while we dropped its lock to
507 * obtain Giant.
508 */
509 VFS_UNLOCK_GIANT(vfslocked);
510
511 KASSERT(object->ref_count != 0,
512 ("vm_object_deallocate: object deallocated too many times: %d", object->type));
513
514 /*
515 * If the reference count goes to 0 we start calling
516 * vm_object_terminate() on the object chain.
517 * A ref count of 1 may be a special case depending on the
518 * shadow count being 0 or 1.
519 */
520 object->ref_count--;
521 if (object->ref_count > 1) {
522 VM_OBJECT_UNLOCK(object);
523 return;
524 } else if (object->ref_count == 1) {
525 if (object->shadow_count == 0 &&
526 object->handle == NULL &&
527 (object->type == OBJT_DEFAULT ||
528 object->type == OBJT_SWAP)) {
529 vm_object_set_flag(object, OBJ_ONEMAPPING);
530 } else if ((object->shadow_count == 1) &&
531 (object->handle == NULL) &&
532 (object->type == OBJT_DEFAULT ||
533 object->type == OBJT_SWAP)) {
534 vm_object_t robject;
535
536 robject = LIST_FIRST(&object->shadow_head);
537 KASSERT(robject != NULL,
538 ("vm_object_deallocate: ref_count: %d, shadow_count: %d",
539 object->ref_count,
540 object->shadow_count));
541 if (!VM_OBJECT_TRYLOCK(robject)) {
542 /*
543 * Avoid a potential deadlock.
544 */
545 object->ref_count++;
546 VM_OBJECT_UNLOCK(object);
547 /*
548 * More likely than not the thread
549 * holding robject's lock has lower
550 * priority than the current thread.
551 * Let the lower priority thread run.
552 */
553 pause("vmo_de", 1);
554 continue;
555 }
556 /*
557 * Collapse object into its shadow unless its
558 * shadow is dead. In that case, object will
559 * be deallocated by the thread that is
560 * deallocating its shadow.
561 */
562 if ((robject->flags & OBJ_DEAD) == 0 &&
563 (robject->handle == NULL) &&
564 (robject->type == OBJT_DEFAULT ||
565 robject->type == OBJT_SWAP)) {
566
567 robject->ref_count++;
568retry:
569 if (robject->paging_in_progress) {
570 VM_OBJECT_UNLOCK(object);
571 vm_object_pip_wait(robject,
572 "objde1");
573 temp = robject->backing_object;
574 if (object == temp) {
575 VM_OBJECT_LOCK(object);
576 goto retry;
577 }
578 } else if (object->paging_in_progress) {
579 VM_OBJECT_UNLOCK(robject);
580 object->flags |= OBJ_PIPWNT;
581 msleep(object,
582 VM_OBJECT_MTX(object),
583 PDROP | PVM, "objde2", 0);
584 VM_OBJECT_LOCK(robject);
585 temp = robject->backing_object;
586 if (object == temp) {
587 VM_OBJECT_LOCK(object);
588 goto retry;
589 }
590 } else
591 VM_OBJECT_UNLOCK(object);
592
593 if (robject->ref_count == 1) {
594 robject->ref_count--;
595 object = robject;
596 goto doterm;
597 }
598 object = robject;
599 vm_object_collapse(object);
600 VM_OBJECT_UNLOCK(object);
601 continue;
602 }
603 VM_OBJECT_UNLOCK(robject);
604 }
605 VM_OBJECT_UNLOCK(object);
606 return;
607 }
608doterm:
609 temp = object->backing_object;
610 if (temp != NULL) {
611 VM_OBJECT_LOCK(temp);
612 LIST_REMOVE(object, shadow_list);
613 temp->shadow_count--;
614 temp->generation++;
615 VM_OBJECT_UNLOCK(temp);
616 object->backing_object = NULL;
617 }
618 /*
619 * Don't double-terminate, we could be in a termination
620 * recursion due to the terminate having to sync data
621 * to disk.
622 */
623 if ((object->flags & OBJ_DEAD) == 0)
624 vm_object_terminate(object);
625 else
626 VM_OBJECT_UNLOCK(object);
627 object = temp;
628 }
629}
630
631/*
632 * vm_object_destroy removes the object from the global object list
633 * and frees the space for the object.
634 */
635void
636vm_object_destroy(vm_object_t object)
637{
638
639 /*
640 * Remove the object from the global object list.
641 */
642 mtx_lock(&vm_object_list_mtx);
643 TAILQ_REMOVE(&vm_object_list, object, object_list);
644 mtx_unlock(&vm_object_list_mtx);
645
646 /*
647 * Release the allocation charge.
648 */
649 if (object->uip != NULL) {
650 KASSERT(object->type == OBJT_DEFAULT ||
651 object->type == OBJT_SWAP,
652 ("vm_object_terminate: non-swap obj %p has uip",
653 object));
654 swap_release_by_uid(object->charge, object->uip);
655 object->charge = 0;
656 uifree(object->uip);
657 object->uip = NULL;
658 }
659
660 /*
661 * Free the space for the object.
662 */
663 uma_zfree(obj_zone, object);
664}
665
666/*
667 * vm_object_terminate actually destroys the specified object, freeing
668 * up all previously used resources.
669 *
670 * The object must be locked.
671 * This routine may block.
672 */
673void
674vm_object_terminate(vm_object_t object)
675{
676 vm_page_t p;
677
678 VM_OBJECT_LOCK_ASSERT(object, MA_OWNED);
679
680 /*
681 * Make sure no one uses us.
682 */
683 vm_object_set_flag(object, OBJ_DEAD);
684
685 /*
686 * wait for the pageout daemon to be done with the object
687 */
688 vm_object_pip_wait(object, "objtrm");
689
690 KASSERT(!object->paging_in_progress,
691 ("vm_object_terminate: pageout in progress"));
692
693 /*
694 * Clean and free the pages, as appropriate. All references to the
695 * object are gone, so we don't need to lock it.
696 */
697 if (object->type == OBJT_VNODE) {
698 struct vnode *vp = (struct vnode *)object->handle;
699
700 /*
701 * Clean pages and flush buffers.
702 */
703 vm_object_page_clean(object, 0, 0, OBJPC_SYNC);
704 VM_OBJECT_UNLOCK(object);
705
706 vinvalbuf(vp, V_SAVE, 0, 0);
707
708 VM_OBJECT_LOCK(object);
709 }
710
711 KASSERT(object->ref_count == 0,
712 ("vm_object_terminate: object with references, ref_count=%d",
713 object->ref_count));
714
715 /*
716 * Now free any remaining pages. For internal objects, this also
717 * removes them from paging queues. Don't free wired pages, just
718 * remove them from the object.
719 */
720 while ((p = TAILQ_FIRST(&object->memq)) != NULL) {
721 KASSERT(!p->busy && (p->oflags & VPO_BUSY) == 0,
722 ("vm_object_terminate: freeing busy page %p "
723 "p->busy = %d, p->oflags %x\n", p, p->busy, p->oflags));
724 vm_page_lock(p);
725 vm_page_lock_queues();
726 if (p->wire_count == 0) {
727 vm_page_free(p);
728 cnt.v_pfree++;
729 } else {
730 vm_page_remove(p);
731 }
732 vm_page_unlock_queues();
733 vm_page_unlock(p);
734 }
735
736#if VM_NRESERVLEVEL > 0
737 if (__predict_false(!LIST_EMPTY(&object->rvq)))
738 vm_reserv_break_all(object);
739#endif
740 if (__predict_false(object->cache != NULL))
741 vm_page_cache_free(object, 0, 0);
742
743 /*
744 * Let the pager know object is dead.
745 */
746 vm_pager_deallocate(object);
747 VM_OBJECT_UNLOCK(object);
748
749 vm_object_destroy(object);
750}
751
752/*
753 * vm_object_page_clean
754 *
755 * Clean all dirty pages in the specified range of object. Leaves page
756 * on whatever queue it is currently on. If NOSYNC is set then do not
757 * write out pages with VPO_NOSYNC set (originally comes from MAP_NOSYNC),
758 * leaving the object dirty.
759 *
760 * When stuffing pages asynchronously, allow clustering. XXX we need a
761 * synchronous clustering mode implementation.
762 *
763 * Odd semantics: if start == end, we clean everything.
764 *
765 * The object must be locked.
766 */
767void
768vm_object_page_clean(vm_object_t object, vm_pindex_t start, vm_pindex_t end, int flags)
769{
770 vm_page_t p, np;
771 vm_pindex_t tstart, tend;
772 vm_pindex_t pi;
773 int clearobjflags;
774 int pagerflags;
775 int curgeneration;
776
777 mtx_assert(&vm_page_queue_mtx, MA_NOTOWNED);
778 VM_OBJECT_LOCK_ASSERT(object, MA_OWNED);
779 if ((object->flags & OBJ_MIGHTBEDIRTY) == 0)
780 return;
781 KASSERT(object->type == OBJT_VNODE, ("Not a vnode object"));
782
783 pagerflags = (flags & (OBJPC_SYNC | OBJPC_INVAL)) ? VM_PAGER_PUT_SYNC : VM_PAGER_CLUSTER_OK;
784 pagerflags |= (flags & OBJPC_INVAL) ? VM_PAGER_PUT_INVAL : 0;
785
786 vm_object_set_flag(object, OBJ_CLEANING);
787
788 tstart = start;
789 if (end == 0) {
790 tend = object->size;
791 } else {
792 tend = end;
793 }
794
795 /*
796 * If the caller is smart and only msync()s a range he knows is
797 * dirty, we may be able to avoid an object scan. This results in
798 * a phenominal improvement in performance. We cannot do this
799 * as a matter of course because the object may be huge - e.g.
800 * the size might be in the gigabytes or terrabytes.
801 */
802 if (msync_flush_flags & MSYNC_FLUSH_HARDSEQ) {
803 vm_pindex_t tscan;
804 int scanlimit;
805 int scanreset;
806
807 scanreset = object->resident_page_count / EASY_SCAN_FACTOR;
808 if (scanreset < 16)
809 scanreset = 16;
810 pagerflags |= VM_PAGER_IGNORE_CLEANCHK;
811
812 scanlimit = scanreset;
813 tscan = tstart;
814 while (tscan < tend) {
815 curgeneration = object->generation;
816 p = vm_page_lookup(object, tscan);
817 if (p == NULL || p->valid == 0) {
818 if (--scanlimit == 0)
819 break;
820 ++tscan;
821 continue;
822 }
823 vm_page_lock(p);
824 vm_page_lock_queues();
825 vm_page_test_dirty(p);
826 if (p->dirty == 0) {
827 vm_page_unlock_queues();
828 vm_page_unlock(p);
829 if (--scanlimit == 0)
830 break;
831 ++tscan;
832 continue;
833 }
834 vm_page_unlock_queues();
835 vm_page_unlock(p);
836 /*
837 * If we have been asked to skip nosync pages and
838 * this is a nosync page, we can't continue.
839 */
840 if ((flags & OBJPC_NOSYNC) && (p->oflags & VPO_NOSYNC)) {
841 if (--scanlimit == 0)
842 break;
843 ++tscan;
844 continue;
845 }
846 scanlimit = scanreset;
847
848 /*
849 * This returns 0 if it was unable to busy the first
850 * page (i.e. had to sleep).
851 */
852 tscan += vm_object_page_collect_flush(object, p, curgeneration, pagerflags);
853
854 }
855
856 /*
857 * If everything was dirty and we flushed it successfully,
858 * and the requested range is not the entire object, we
859 * don't have to mess with CLEANCHK or MIGHTBEDIRTY and can
860 * return immediately.
861 */
862 if (tscan >= tend && (tstart || tend < object->size)) {
863 vm_object_clear_flag(object, OBJ_CLEANING);
864 return;
865 }
866 pagerflags &= ~VM_PAGER_IGNORE_CLEANCHK;
867 }
868
869 /*
870 * Generally set CLEANCHK interlock and make the page read-only so
871 * we can then clear the object flags.
872 *
873 * However, if this is a nosync mmap then the object is likely to
874 * stay dirty so do not mess with the page and do not clear the
875 * object flags.
876 */
877 clearobjflags = 1;
878 TAILQ_FOREACH(p, &object->memq, listq) {
879 p->oflags |= VPO_CLEANCHK;
880 if ((flags & OBJPC_NOSYNC) && (p->oflags & VPO_NOSYNC))
881 clearobjflags = 0;
882 else {
883 vm_page_lock(p);
884 vm_page_lock_queues();
885 pmap_remove_write(p);
886 vm_page_unlock_queues();
887 vm_page_unlock(p);
888 }
889 }
890
891 if (clearobjflags && (tstart == 0) && (tend == object->size))
892 vm_object_clear_flag(object, OBJ_MIGHTBEDIRTY);
893
894rescan:
895 curgeneration = object->generation;
896
897 for (p = TAILQ_FIRST(&object->memq); p; p = np) {
898 int n;
899
900 np = TAILQ_NEXT(p, listq);
901
902again:
903 pi = p->pindex;
904 if ((p->oflags & VPO_CLEANCHK) == 0 ||
905 (pi < tstart) || (pi >= tend) ||
906 p->valid == 0) {
907 p->oflags &= ~VPO_CLEANCHK;
908 continue;
909 }
910
911 vm_page_lock(p);
912 vm_page_lock_queues();
913 vm_page_test_dirty(p);
914 if (p->dirty == 0) {
915 vm_page_unlock_queues();
916 vm_page_unlock(p);
917 p->oflags &= ~VPO_CLEANCHK;
918 continue;
919 }
920 vm_page_unlock_queues();
921 vm_page_unlock(p);
922 /*
923 * If we have been asked to skip nosync pages and this is a
924 * nosync page, skip it. Note that the object flags were
925 * not cleared in this case so we do not have to set them.
926 */
927 if ((flags & OBJPC_NOSYNC) && (p->oflags & VPO_NOSYNC)) {
928 p->oflags &= ~VPO_CLEANCHK;
929 continue;
930 }
931
932 n = vm_object_page_collect_flush(object, p,
933 curgeneration, pagerflags);
934 if (n == 0)
935 goto rescan;
936
937 if (object->generation != curgeneration)
938 goto rescan;
939
940 /*
941 * Try to optimize the next page. If we can't we pick up
942 * our (random) scan where we left off.
943 */
944 if (msync_flush_flags & MSYNC_FLUSH_SOFTSEQ)
945 if ((p = vm_page_lookup(object, pi + n)) != NULL)
946 goto again;
947 }
948#if 0
949 VOP_FSYNC(vp, (pagerflags & VM_PAGER_PUT_SYNC)?MNT_WAIT:0, curproc);
950#endif
951
952 vm_object_clear_flag(object, OBJ_CLEANING);
953 return;
954}
955
956static int
957vm_object_page_collect_flush(vm_object_t object, vm_page_t p, int curgeneration, int pagerflags)
958{
959 int runlen;
960 int maxf;
961 int chkb;
962 int maxb;
963 int i;
964 vm_pindex_t pi;
965 vm_page_t maf[vm_pageout_page_count];
966 vm_page_t mab[vm_pageout_page_count];
967 vm_page_t ma[vm_pageout_page_count];
968
969 mtx_assert(&vm_page_queue_mtx, MA_NOTOWNED);
970 vm_page_lock_assert(p, MA_NOTOWNED);
971 VM_OBJECT_LOCK_ASSERT(object, MA_OWNED);
972 pi = p->pindex;
973 while (vm_page_sleep_if_busy(p, TRUE, "vpcwai")) {
974 if (object->generation != curgeneration) {
975 return(0);
976 }
977 }
978 maxf = 0;
979 for(i = 1; i < vm_pageout_page_count; i++) {
980 vm_page_t tp;
981
982 if ((tp = vm_page_lookup(object, pi + i)) != NULL) {
983 if ((tp->oflags & VPO_BUSY) ||
984 ((pagerflags & VM_PAGER_IGNORE_CLEANCHK) == 0 &&
985 (tp->oflags & VPO_CLEANCHK) == 0) ||
986 (tp->busy != 0))
987 break;
988 vm_page_lock(tp);
989 vm_page_lock_queues();
990 vm_page_test_dirty(tp);
991 if (tp->dirty == 0) {
992 vm_page_unlock(tp);
993 vm_page_unlock_queues();
994 tp->oflags &= ~VPO_CLEANCHK;
995 break;
996 }
997 vm_page_unlock(tp);
998 vm_page_unlock_queues();
999 maf[ i - 1 ] = tp;
1000 maxf++;
1001 continue;
1002 }
1003 break;
1004 }
1005
1006 maxb = 0;
1007 chkb = vm_pageout_page_count - maxf;
1008 if (chkb) {
1009 for(i = 1; i < chkb;i++) {
1010 vm_page_t tp;
1011
1012 if ((tp = vm_page_lookup(object, pi - i)) != NULL) {
1013 if ((tp->oflags & VPO_BUSY) ||
1014 ((pagerflags & VM_PAGER_IGNORE_CLEANCHK) == 0 &&
1015 (tp->oflags & VPO_CLEANCHK) == 0) ||
1016 (tp->busy != 0))
1017 break;
1018 vm_page_lock(tp);
1019 vm_page_lock_queues();
1020 vm_page_test_dirty(tp);
1021 if (tp->dirty == 0) {
1022 vm_page_unlock_queues();
1023 vm_page_unlock(tp);
1024 tp->oflags &= ~VPO_CLEANCHK;
1025 break;
1026 }
1027 vm_page_unlock_queues();
1028 vm_page_unlock(tp);
1029 mab[ i - 1 ] = tp;
1030 maxb++;
1031 continue;
1032 }
1033 break;
1034 }
1035 }
1036
1037 for(i = 0; i < maxb; i++) {
1038 int index = (maxb - i) - 1;
1039 ma[index] = mab[i];
1040 ma[index]->oflags &= ~VPO_CLEANCHK;
1041 }
1042 p->oflags &= ~VPO_CLEANCHK;
1043 ma[maxb] = p;
1044 for(i = 0; i < maxf; i++) {
1045 int index = (maxb + i) + 1;
1046 ma[index] = maf[i];
1047 ma[index]->oflags &= ~VPO_CLEANCHK;
1048 }
1049 runlen = maxb + maxf + 1;
1050
1051 vm_pageout_flush(ma, runlen, pagerflags);
1052 for (i = 0; i < runlen; i++) {
1053 if (ma[i]->dirty) {
1054 vm_page_lock(ma[i]);
1055 vm_page_lock_queues();
1056 pmap_remove_write(ma[i]);
1057 vm_page_unlock_queues();
1058 vm_page_unlock(ma[i]);
1059 ma[i]->oflags |= VPO_CLEANCHK;
1060
1061 /*
1062 * maxf will end up being the actual number of pages
1063 * we wrote out contiguously, non-inclusive of the
1064 * first page. We do not count look-behind pages.
1065 */
1066 if (i >= maxb + 1 && (maxf > i - maxb - 1))
1067 maxf = i - maxb - 1;
1068 }
1069 }
1070 return(maxf + 1);
1071}
1072
1073/*
1074 * Note that there is absolutely no sense in writing out
1075 * anonymous objects, so we track down the vnode object
1076 * to write out.
1077 * We invalidate (remove) all pages from the address space
1078 * for semantic correctness.
1079 *
1080 * Note: certain anonymous maps, such as MAP_NOSYNC maps,
1081 * may start out with a NULL object.
1082 */
1083void
1084vm_object_sync(vm_object_t object, vm_ooffset_t offset, vm_size_t size,
1085 boolean_t syncio, boolean_t invalidate)
1086{
1087 vm_object_t backing_object;
1088 struct vnode *vp;
1089 struct mount *mp;
1090 int flags;
1091
1092 if (object == NULL)
1093 return;
1094 VM_OBJECT_LOCK(object);
1095 while ((backing_object = object->backing_object) != NULL) {
1096 VM_OBJECT_LOCK(backing_object);
1097 offset += object->backing_object_offset;
1098 VM_OBJECT_UNLOCK(object);
1099 object = backing_object;
1100 if (object->size < OFF_TO_IDX(offset + size))
1101 size = IDX_TO_OFF(object->size) - offset;
1102 }
1103 /*
1104 * Flush pages if writing is allowed, invalidate them
1105 * if invalidation requested. Pages undergoing I/O
1106 * will be ignored by vm_object_page_remove().
1107 *
1108 * We cannot lock the vnode and then wait for paging
1109 * to complete without deadlocking against vm_fault.
1110 * Instead we simply call vm_object_page_remove() and
1111 * allow it to block internally on a page-by-page
1112 * basis when it encounters pages undergoing async
1113 * I/O.
1114 */
1115 if (object->type == OBJT_VNODE &&
1116 (object->flags & OBJ_MIGHTBEDIRTY) != 0) {
1117 int vfslocked;
1118 vp = object->handle;
1119 VM_OBJECT_UNLOCK(object);
1120 (void) vn_start_write(vp, &mp, V_WAIT);
1121 vfslocked = VFS_LOCK_GIANT(vp->v_mount);
1122 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
1123 flags = (syncio || invalidate) ? OBJPC_SYNC : 0;
1124 flags |= invalidate ? OBJPC_INVAL : 0;
1125 VM_OBJECT_LOCK(object);
1126 vm_object_page_clean(object,
1127 OFF_TO_IDX(offset),
1128 OFF_TO_IDX(offset + size + PAGE_MASK),
1129 flags);
1130 VM_OBJECT_UNLOCK(object);
1131 VOP_UNLOCK(vp, 0);
1132 VFS_UNLOCK_GIANT(vfslocked);
1133 vn_finished_write(mp);
1134 VM_OBJECT_LOCK(object);
1135 }
1136 if ((object->type == OBJT_VNODE ||
1137 object->type == OBJT_DEVICE) && invalidate) {
1138 boolean_t purge;
1139 purge = old_msync || (object->type == OBJT_DEVICE);
1140 vm_object_page_remove(object,
1141 OFF_TO_IDX(offset),
1142 OFF_TO_IDX(offset + size + PAGE_MASK),
1143 purge ? FALSE : TRUE);
1144 }
1145 VM_OBJECT_UNLOCK(object);
1146}
1147
1148/*
1149 * vm_object_madvise:
1150 *
1151 * Implements the madvise function at the object/page level.
1152 *
1153 * MADV_WILLNEED (any object)
1154 *
1155 * Activate the specified pages if they are resident.
1156 *
1157 * MADV_DONTNEED (any object)
1158 *
1159 * Deactivate the specified pages if they are resident.
1160 *
1161 * MADV_FREE (OBJT_DEFAULT/OBJT_SWAP objects,
1162 * OBJ_ONEMAPPING only)
1163 *
1164 * Deactivate and clean the specified pages if they are
1165 * resident. This permits the process to reuse the pages
1166 * without faulting or the kernel to reclaim the pages
1167 * without I/O.
1168 */
1169void
1170vm_object_madvise(vm_object_t object, vm_pindex_t pindex, int count, int advise)
1171{
1172 vm_pindex_t end, tpindex;
1173 vm_object_t backing_object, tobject;
1174 vm_page_t m;
1175
1176 if (object == NULL)
1177 return;
1178 VM_OBJECT_LOCK(object);
1179 end = pindex + count;
1180 /*
1181 * Locate and adjust resident pages
1182 */
1183 for (; pindex < end; pindex += 1) {
1184relookup:
1185 tobject = object;
1186 tpindex = pindex;
1187shadowlookup:
1188 /*
1189 * MADV_FREE only operates on OBJT_DEFAULT or OBJT_SWAP pages
1190 * and those pages must be OBJ_ONEMAPPING.
1191 */
1192 if (advise == MADV_FREE) {
1193 if ((tobject->type != OBJT_DEFAULT &&
1194 tobject->type != OBJT_SWAP) ||
1195 (tobject->flags & OBJ_ONEMAPPING) == 0) {
1196 goto unlock_tobject;
1197 }
1198 } else if (tobject->type == OBJT_PHYS)
1199 goto unlock_tobject;
1200 m = vm_page_lookup(tobject, tpindex);
1201 if (m == NULL && advise == MADV_WILLNEED) {
1202 /*
1203 * If the page is cached, reactivate it.
1204 */
1205 m = vm_page_alloc(tobject, tpindex, VM_ALLOC_IFCACHED |
1206 VM_ALLOC_NOBUSY);
1207 }
1208 if (m == NULL) {
1209 /*
1210 * There may be swap even if there is no backing page
1211 */
1212 if (advise == MADV_FREE && tobject->type == OBJT_SWAP)
1213 swap_pager_freespace(tobject, tpindex, 1);
1214 /*
1215 * next object
1216 */
1217 backing_object = tobject->backing_object;
1218 if (backing_object == NULL)
1219 goto unlock_tobject;
1220 VM_OBJECT_LOCK(backing_object);
1221 tpindex += OFF_TO_IDX(tobject->backing_object_offset);
1222 if (tobject != object)
1223 VM_OBJECT_UNLOCK(tobject);
1224 tobject = backing_object;
1225 goto shadowlookup;
1226 } else if (m->valid != VM_PAGE_BITS_ALL)
1227 goto unlock_tobject;
1228 /*
1229 * If the page is not in a normal state, skip it.
1230 */
1231 vm_page_lock(m);
1232 vm_page_lock_queues();
1233 if (m->hold_count != 0 || m->wire_count != 0) {
1234 vm_page_unlock_queues();
1235 vm_page_unlock(m);
1236 goto unlock_tobject;
1237 }
1238 if ((m->oflags & VPO_BUSY) || m->busy) {
1239 if (advise == MADV_WILLNEED)
1240 /*
1241 * Reference the page before unlocking and
1242 * sleeping so that the page daemon is less
1243 * likely to reclaim it.
1244 */
1245 vm_page_flag_set(m, PG_REFERENCED);
1246 vm_page_unlock_queues();
1247 vm_page_unlock(m);
1248 if (object != tobject)
1249 VM_OBJECT_UNLOCK(object);
1250 m->oflags |= VPO_WANTED;
1251 msleep(m, VM_OBJECT_MTX(tobject), PDROP | PVM, "madvpo",
1252 0);
1253 VM_OBJECT_LOCK(object);
1254 goto relookup;
1255 }
1256 if (advise == MADV_WILLNEED) {
1257 vm_page_activate(m);
1258 } else if (advise == MADV_DONTNEED) {
1259 vm_page_dontneed(m);
1260 } else if (advise == MADV_FREE) {
1261 /*
1262 * Mark the page clean. This will allow the page
1263 * to be freed up by the system. However, such pages
1264 * are often reused quickly by malloc()/free()
1265 * so we do not do anything that would cause
1266 * a page fault if we can help it.
1267 *
1268 * Specifically, we do not try to actually free
1269 * the page now nor do we try to put it in the
1270 * cache (which would cause a page fault on reuse).
1271 *
1272 * But we do make the page is freeable as we
1273 * can without actually taking the step of unmapping
1274 * it.
1275 */
1276 pmap_clear_modify(m);
1277 m->dirty = 0;
1278 m->act_count = 0;
1279 vm_page_dontneed(m);
1280 }
1281 vm_page_unlock_queues();
1282 vm_page_unlock(m);
1283 if (advise == MADV_FREE && tobject->type == OBJT_SWAP)
1284 swap_pager_freespace(tobject, tpindex, 1);
1285unlock_tobject:
1286 if (tobject != object)
1287 VM_OBJECT_UNLOCK(tobject);
1288 }
1289 VM_OBJECT_UNLOCK(object);
1290}
1291
1292/*
1293 * vm_object_shadow:
1294 *
1295 * Create a new object which is backed by the
1296 * specified existing object range. The source
1297 * object reference is deallocated.
1298 *
1299 * The new object and offset into that object
1300 * are returned in the source parameters.
1301 */
1302void
1303vm_object_shadow(
1304 vm_object_t *object, /* IN/OUT */
1305 vm_ooffset_t *offset, /* IN/OUT */
1306 vm_size_t length)
1307{
1308 vm_object_t source;
1309 vm_object_t result;
1310
1311 source = *object;
1312
1313 /*
1314 * Don't create the new object if the old object isn't shared.
1315 */
1316 if (source != NULL) {
1317 VM_OBJECT_LOCK(source);
1318 if (source->ref_count == 1 &&
1319 source->handle == NULL &&
1320 (source->type == OBJT_DEFAULT ||
1321 source->type == OBJT_SWAP)) {
1322 VM_OBJECT_UNLOCK(source);
1323 return;
1324 }
1325 VM_OBJECT_UNLOCK(source);
1326 }
1327
1328 /*
1329 * Allocate a new object with the given length.
1330 */
1331 result = vm_object_allocate(OBJT_DEFAULT, length);
1332
1333 /*
1334 * The new object shadows the source object, adding a reference to it.
1335 * Our caller changes his reference to point to the new object,
1336 * removing a reference to the source object. Net result: no change
1337 * of reference count.
1338 *
1339 * Try to optimize the result object's page color when shadowing
1340 * in order to maintain page coloring consistency in the combined
1341 * shadowed object.
1342 */
1343 result->backing_object = source;
1344 /*
1345 * Store the offset into the source object, and fix up the offset into
1346 * the new object.
1347 */
1348 result->backing_object_offset = *offset;
1349 if (source != NULL) {
1350 VM_OBJECT_LOCK(source);
1351 LIST_INSERT_HEAD(&source->shadow_head, result, shadow_list);
1352 source->shadow_count++;
1353 source->generation++;
1354#if VM_NRESERVLEVEL > 0
1355 result->flags |= source->flags & OBJ_COLORED;
1356 result->pg_color = (source->pg_color + OFF_TO_IDX(*offset)) &
1357 ((1 << (VM_NFREEORDER - 1)) - 1);
1358#endif
1359 VM_OBJECT_UNLOCK(source);
1360 }
1361
1362
1363 /*
1364 * Return the new things
1365 */
1366 *offset = 0;
1367 *object = result;
1368}
1369
1370/*
1371 * vm_object_split:
1372 *
1373 * Split the pages in a map entry into a new object. This affords
1374 * easier removal of unused pages, and keeps object inheritance from
1375 * being a negative impact on memory usage.
1376 */
1377void
1378vm_object_split(vm_map_entry_t entry)
1379{
1380 vm_page_t m, m_next;
1381 vm_object_t orig_object, new_object, source;
1382 vm_pindex_t idx, offidxstart;
1383 vm_size_t size;
1384
1385 orig_object = entry->object.vm_object;
1386 if (orig_object->type != OBJT_DEFAULT && orig_object->type != OBJT_SWAP)
1387 return;
1388 if (orig_object->ref_count <= 1)
1389 return;
1390 VM_OBJECT_UNLOCK(orig_object);
1391
1392 offidxstart = OFF_TO_IDX(entry->offset);
1393 size = atop(entry->end - entry->start);
1394
1395 /*
1396 * If swap_pager_copy() is later called, it will convert new_object
1397 * into a swap object.
1398 */
1399 new_object = vm_object_allocate(OBJT_DEFAULT, size);
1400
1401 /*
1402 * At this point, the new object is still private, so the order in
1403 * which the original and new objects are locked does not matter.
1404 */
1405 VM_OBJECT_LOCK(new_object);
1406 VM_OBJECT_LOCK(orig_object);
1407 source = orig_object->backing_object;
1408 if (source != NULL) {
1409 VM_OBJECT_LOCK(source);
1410 if ((source->flags & OBJ_DEAD) != 0) {
1411 VM_OBJECT_UNLOCK(source);
1412 VM_OBJECT_UNLOCK(orig_object);
1413 VM_OBJECT_UNLOCK(new_object);
1414 vm_object_deallocate(new_object);
1415 VM_OBJECT_LOCK(orig_object);
1416 return;
1417 }
1418 LIST_INSERT_HEAD(&source->shadow_head,
1419 new_object, shadow_list);
1420 source->shadow_count++;
1421 source->generation++;
1422 vm_object_reference_locked(source); /* for new_object */
1423 vm_object_clear_flag(source, OBJ_ONEMAPPING);
1424 VM_OBJECT_UNLOCK(source);
1425 new_object->backing_object_offset =
1426 orig_object->backing_object_offset + entry->offset;
1427 new_object->backing_object = source;
1428 }
1429 if (orig_object->uip != NULL) {
1430 new_object->uip = orig_object->uip;
1431 uihold(orig_object->uip);
1432 new_object->charge = ptoa(size);
1433 KASSERT(orig_object->charge >= ptoa(size),
1434 ("orig_object->charge < 0"));
1435 orig_object->charge -= ptoa(size);
1436 }
1437retry:
1438 if ((m = TAILQ_FIRST(&orig_object->memq)) != NULL) {
1439 if (m->pindex < offidxstart) {
1440 m = vm_page_splay(offidxstart, orig_object->root);
1441 if ((orig_object->root = m)->pindex < offidxstart)
1442 m = TAILQ_NEXT(m, listq);
1443 }
1444 }
1445 for (; m != NULL && (idx = m->pindex - offidxstart) < size;
1446 m = m_next) {
1447 m_next = TAILQ_NEXT(m, listq);
1448
1449 /*
1450 * We must wait for pending I/O to complete before we can
1451 * rename the page.
1452 *
1453 * We do not have to VM_PROT_NONE the page as mappings should
1454 * not be changed by this operation.
1455 */
1456 if ((m->oflags & VPO_BUSY) || m->busy) {
1457 VM_OBJECT_UNLOCK(new_object);
1458 m->oflags |= VPO_WANTED;
1459 msleep(m, VM_OBJECT_MTX(orig_object), PVM, "spltwt", 0);
1460 VM_OBJECT_LOCK(new_object);
1461 goto retry;
1462 }
1463 vm_page_lock(m);
1464 vm_page_lock_queues();
1465 vm_page_rename(m, new_object, idx);
1466 vm_page_unlock_queues();
1467 vm_page_unlock(m);
1468 /* page automatically made dirty by rename and cache handled */
1469 vm_page_busy(m);
1470 }
1471 if (orig_object->type == OBJT_SWAP) {
1472 /*
1473 * swap_pager_copy() can sleep, in which case the orig_object's
1474 * and new_object's locks are released and reacquired.
1475 */
1476 swap_pager_copy(orig_object, new_object, offidxstart, 0);
1477
1478 /*
1479 * Transfer any cached pages from orig_object to new_object.
1480 */
1481 if (__predict_false(orig_object->cache != NULL))
1482 vm_page_cache_transfer(orig_object, offidxstart,
1483 new_object);
1484 }
1485 VM_OBJECT_UNLOCK(orig_object);
1486 TAILQ_FOREACH(m, &new_object->memq, listq)
1487 vm_page_wakeup(m);
1488 VM_OBJECT_UNLOCK(new_object);
1489 entry->object.vm_object = new_object;
1490 entry->offset = 0LL;
1491 vm_object_deallocate(orig_object);
1492 VM_OBJECT_LOCK(new_object);
1493}
1494
1495#define OBSC_TEST_ALL_SHADOWED 0x0001
1496#define OBSC_COLLAPSE_NOWAIT 0x0002
1497#define OBSC_COLLAPSE_WAIT 0x0004
1498
1499static int
1500vm_object_backing_scan(vm_object_t object, int op)
1501{
1502 int r = 1;
1503 vm_page_t p;
1504 vm_object_t backing_object;
1505 vm_pindex_t backing_offset_index;
1506
1507 VM_OBJECT_LOCK_ASSERT(object, MA_OWNED);
1508 VM_OBJECT_LOCK_ASSERT(object->backing_object, MA_OWNED);
1509
1510 backing_object = object->backing_object;
1511 backing_offset_index = OFF_TO_IDX(object->backing_object_offset);
1512
1513 /*
1514 * Initial conditions
1515 */
1516 if (op & OBSC_TEST_ALL_SHADOWED) {
1517 /*
1518 * We do not want to have to test for the existence of cache
1519 * or swap pages in the backing object. XXX but with the
1520 * new swapper this would be pretty easy to do.
1521 *
1522 * XXX what about anonymous MAP_SHARED memory that hasn't
1523 * been ZFOD faulted yet? If we do not test for this, the
1524 * shadow test may succeed! XXX
1525 */
1526 if (backing_object->type != OBJT_DEFAULT) {
1527 return (0);
1528 }
1529 }
1530 if (op & OBSC_COLLAPSE_WAIT) {
1531 vm_object_set_flag(backing_object, OBJ_DEAD);
1532 }
1533
1534 /*
1535 * Our scan
1536 */
1537 p = TAILQ_FIRST(&backing_object->memq);
1538 while (p) {
1539 vm_page_t next = TAILQ_NEXT(p, listq);
1540 vm_pindex_t new_pindex = p->pindex - backing_offset_index;
1541
1542 if (op & OBSC_TEST_ALL_SHADOWED) {
1543 vm_page_t pp;
1544
1545 /*
1546 * Ignore pages outside the parent object's range
1547 * and outside the parent object's mapping of the
1548 * backing object.
1549 *
1550 * note that we do not busy the backing object's
1551 * page.
1552 */
1553 if (
1554 p->pindex < backing_offset_index ||
1555 new_pindex >= object->size
1556 ) {
1557 p = next;
1558 continue;
1559 }
1560
1561 /*
1562 * See if the parent has the page or if the parent's
1563 * object pager has the page. If the parent has the
1564 * page but the page is not valid, the parent's
1565 * object pager must have the page.
1566 *
1567 * If this fails, the parent does not completely shadow
1568 * the object and we might as well give up now.
1569 */
1570
1571 pp = vm_page_lookup(object, new_pindex);
1572 if (
1573 (pp == NULL || pp->valid == 0) &&
1574 !vm_pager_has_page(object, new_pindex, NULL, NULL)
1575 ) {
1576 r = 0;
1577 break;
1578 }
1579 }
1580
1581 /*
1582 * Check for busy page
1583 */
1584 if (op & (OBSC_COLLAPSE_WAIT | OBSC_COLLAPSE_NOWAIT)) {
1585 vm_page_t pp;
1586
1587 if (op & OBSC_COLLAPSE_NOWAIT) {
1588 if ((p->oflags & VPO_BUSY) ||
1589 !p->valid ||
1590 p->busy) {
1591 p = next;
1592 continue;
1593 }
1594 } else if (op & OBSC_COLLAPSE_WAIT) {
1595 if ((p->oflags & VPO_BUSY) || p->busy) {
1596 VM_OBJECT_UNLOCK(object);
1597 p->oflags |= VPO_WANTED;
1598 msleep(p, VM_OBJECT_MTX(backing_object),
1599 PDROP | PVM, "vmocol", 0);
1600 VM_OBJECT_LOCK(object);
1601 VM_OBJECT_LOCK(backing_object);
1602 /*
1603 * If we slept, anything could have
1604 * happened. Since the object is
1605 * marked dead, the backing offset
1606 * should not have changed so we
1607 * just restart our scan.
1608 */
1609 p = TAILQ_FIRST(&backing_object->memq);
1610 continue;
1611 }
1612 }
1613
1614 KASSERT(
1615 p->object == backing_object,
1616 ("vm_object_backing_scan: object mismatch")
1617 );
1618
1619 /*
1620 * Destroy any associated swap
1621 */
1622 if (backing_object->type == OBJT_SWAP) {
1623 swap_pager_freespace(
1624 backing_object,
1625 p->pindex,
1626 1
1627 );
1628 }
1629
1630 if (
1631 p->pindex < backing_offset_index ||
1632 new_pindex >= object->size
1633 ) {
1634 /*
1635 * Page is out of the parent object's range, we
1636 * can simply destroy it.
1637 */
1638 vm_page_lock(p);
1639 vm_page_lock_queues();
1640 KASSERT(!pmap_page_is_mapped(p),
1641 ("freeing mapped page %p", p));
1642 if (p->wire_count == 0)
1643 vm_page_free(p);
1644 else
1645 vm_page_remove(p);
1646 vm_page_unlock_queues();
1647 vm_page_unlock(p);
1648 p = next;
1649 continue;
1650 }
1651
1652 pp = vm_page_lookup(object, new_pindex);
1653 if (
1654 pp != NULL ||
1655 vm_pager_has_page(object, new_pindex, NULL, NULL)
1656 ) {
1657 /*
1658 * page already exists in parent OR swap exists
1659 * for this location in the parent. Destroy
1660 * the original page from the backing object.
1661 *
1662 * Leave the parent's page alone
1663 */
1664 vm_page_lock(p);
1665 vm_page_lock_queues();
1666 KASSERT(!pmap_page_is_mapped(p),
1667 ("freeing mapped page %p", p));
1668 if (p->wire_count == 0)
1669 vm_page_free(p);
1670 else
1671 vm_page_remove(p);
1672 vm_page_unlock_queues();
1673 vm_page_unlock(p);
1674 p = next;
1675 continue;
1676 }
1677
1678#if VM_NRESERVLEVEL > 0
1679 /*
1680 * Rename the reservation.
1681 */
1682 vm_reserv_rename(p, object, backing_object,
1683 backing_offset_index);
1684#endif
1685
1686 /*
1687 * Page does not exist in parent, rename the
1688 * page from the backing object to the main object.
1689 *
1690 * If the page was mapped to a process, it can remain
1691 * mapped through the rename.
1692 */
1693 vm_page_lock(p);
1694 vm_page_lock_queues();
1695 vm_page_rename(p, object, new_pindex);
1696 vm_page_unlock_queues();
1697 vm_page_unlock(p);
1698 /* page automatically made dirty by rename */
1699 }
1700 p = next;
1701 }
1702 return (r);
1703}
1704
1705
1706/*
1707 * this version of collapse allows the operation to occur earlier and
1708 * when paging_in_progress is true for an object... This is not a complete
1709 * operation, but should plug 99.9% of the rest of the leaks.
1710 */
1711static void
1712vm_object_qcollapse(vm_object_t object)
1713{
1714 vm_object_t backing_object = object->backing_object;
1715
1716 VM_OBJECT_LOCK_ASSERT(object, MA_OWNED);
1717 VM_OBJECT_LOCK_ASSERT(backing_object, MA_OWNED);
1718
1719 if (backing_object->ref_count != 1)
1720 return;
1721
1722 vm_object_backing_scan(object, OBSC_COLLAPSE_NOWAIT);
1723}
1724
1725/*
1726 * vm_object_collapse:
1727 *
1728 * Collapse an object with the object backing it.
1729 * Pages in the backing object are moved into the
1730 * parent, and the backing object is deallocated.
1731 */
1732void
1733vm_object_collapse(vm_object_t object)
1734{
1735 VM_OBJECT_LOCK_ASSERT(object, MA_OWNED);
1736
1737 while (TRUE) {
1738 vm_object_t backing_object;
1739
1740 /*
1741 * Verify that the conditions are right for collapse:
1742 *
1743 * The object exists and the backing object exists.
1744 */
1745 if ((backing_object = object->backing_object) == NULL)
1746 break;
1747
1748 /*
1749 * we check the backing object first, because it is most likely
1750 * not collapsable.
1751 */
1752 VM_OBJECT_LOCK(backing_object);
1753 if (backing_object->handle != NULL ||
1754 (backing_object->type != OBJT_DEFAULT &&
1755 backing_object->type != OBJT_SWAP) ||
1756 (backing_object->flags & OBJ_DEAD) ||
1757 object->handle != NULL ||
1758 (object->type != OBJT_DEFAULT &&
1759 object->type != OBJT_SWAP) ||
1760 (object->flags & OBJ_DEAD)) {
1761 VM_OBJECT_UNLOCK(backing_object);
1762 break;
1763 }
1764
1765 if (
1766 object->paging_in_progress != 0 ||
1767 backing_object->paging_in_progress != 0
1768 ) {
1769 vm_object_qcollapse(object);
1770 VM_OBJECT_UNLOCK(backing_object);
1771 break;
1772 }
1773 /*
1774 * We know that we can either collapse the backing object (if
1775 * the parent is the only reference to it) or (perhaps) have
1776 * the parent bypass the object if the parent happens to shadow
1777 * all the resident pages in the entire backing object.
1778 *
1779 * This is ignoring pager-backed pages such as swap pages.
1780 * vm_object_backing_scan fails the shadowing test in this
1781 * case.
1782 */
1783 if (backing_object->ref_count == 1) {
1784 /*
1785 * If there is exactly one reference to the backing
1786 * object, we can collapse it into the parent.
1787 */
1788 vm_object_backing_scan(object, OBSC_COLLAPSE_WAIT);
1789
1790#if VM_NRESERVLEVEL > 0
1791 /*
1792 * Break any reservations from backing_object.
1793 */
1794 if (__predict_false(!LIST_EMPTY(&backing_object->rvq)))
1795 vm_reserv_break_all(backing_object);
1796#endif
1797
1798 /*
1799 * Move the pager from backing_object to object.
1800 */
1801 if (backing_object->type == OBJT_SWAP) {
1802 /*
1803 * swap_pager_copy() can sleep, in which case
1804 * the backing_object's and object's locks are
1805 * released and reacquired.
1806 */
1807 swap_pager_copy(
1808 backing_object,
1809 object,
1810 OFF_TO_IDX(object->backing_object_offset), TRUE);
1811
1812 /*
1813 * Free any cached pages from backing_object.
1814 */
1815 if (__predict_false(backing_object->cache != NULL))
1816 vm_page_cache_free(backing_object, 0, 0);
1817 }
1818 /*
1819 * Object now shadows whatever backing_object did.
1820 * Note that the reference to
1821 * backing_object->backing_object moves from within
1822 * backing_object to within object.
1823 */
1824 LIST_REMOVE(object, shadow_list);
1825 backing_object->shadow_count--;
1826 backing_object->generation++;
1827 if (backing_object->backing_object) {
1828 VM_OBJECT_LOCK(backing_object->backing_object);
1829 LIST_REMOVE(backing_object, shadow_list);
1830 LIST_INSERT_HEAD(
1831 &backing_object->backing_object->shadow_head,
1832 object, shadow_list);
1833 /*
1834 * The shadow_count has not changed.
1835 */
1836 backing_object->backing_object->generation++;
1837 VM_OBJECT_UNLOCK(backing_object->backing_object);
1838 }
1839 object->backing_object = backing_object->backing_object;
1840 object->backing_object_offset +=
1841 backing_object->backing_object_offset;
1842
1843 /*
1844 * Discard backing_object.
1845 *
1846 * Since the backing object has no pages, no pager left,
1847 * and no object references within it, all that is
1848 * necessary is to dispose of it.
1849 */
1850 KASSERT(backing_object->ref_count == 1, (
1851"backing_object %p was somehow re-referenced during collapse!",
1852 backing_object));
1853 VM_OBJECT_UNLOCK(backing_object);
1854 vm_object_destroy(backing_object);
1855
1856 object_collapses++;
1857 } else {
1858 vm_object_t new_backing_object;
1859
1860 /*
1861 * If we do not entirely shadow the backing object,
1862 * there is nothing we can do so we give up.
1863 */
1864 if (object->resident_page_count != object->size &&
1865 vm_object_backing_scan(object,
1866 OBSC_TEST_ALL_SHADOWED) == 0) {
1867 VM_OBJECT_UNLOCK(backing_object);
1868 break;
1869 }
1870
1871 /*
1872 * Make the parent shadow the next object in the
1873 * chain. Deallocating backing_object will not remove
1874 * it, since its reference count is at least 2.
1875 */
1876 LIST_REMOVE(object, shadow_list);
1877 backing_object->shadow_count--;
1878 backing_object->generation++;
1879
1880 new_backing_object = backing_object->backing_object;
1881 if ((object->backing_object = new_backing_object) != NULL) {
1882 VM_OBJECT_LOCK(new_backing_object);
1883 LIST_INSERT_HEAD(
1884 &new_backing_object->shadow_head,
1885 object,
1886 shadow_list
1887 );
1888 new_backing_object->shadow_count++;
1889 new_backing_object->generation++;
1890 vm_object_reference_locked(new_backing_object);
1891 VM_OBJECT_UNLOCK(new_backing_object);
1892 object->backing_object_offset +=
1893 backing_object->backing_object_offset;
1894 }
1895
1896 /*
1897 * Drop the reference count on backing_object. Since
1898 * its ref_count was at least 2, it will not vanish.
1899 */
1900 backing_object->ref_count--;
1901 VM_OBJECT_UNLOCK(backing_object);
1902 object_bypasses++;
1903 }
1904
1905 /*
1906 * Try again with this object's new backing object.
1907 */
1908 }
1909}
1910
1911/*
1912 * vm_object_page_remove:
1913 *
1914 * For the given object, either frees or invalidates each of the
1915 * specified pages. In general, a page is freed. However, if a
1916 * page is wired for any reason other than the existence of a
1917 * managed, wired mapping, then it may be invalidated but not
1918 * removed from the object. Pages are specified by the given
1919 * range ["start", "end") and Boolean "clean_only". As a
1920 * special case, if "end" is zero, then the range extends from
1921 * "start" to the end of the object. If "clean_only" is TRUE,
1922 * then only the non-dirty pages within the specified range are
1923 * affected.
1924 *
1925 * In general, this operation should only be performed on objects
1926 * that contain managed pages. There are two exceptions. First,
1927 * it may be performed on the kernel and kmem objects. Second,
1928 * it may be used by msync(..., MS_INVALIDATE) to invalidate
1929 * device-backed pages.
1930 *
1931 * The object must be locked.
1932 */
1933void
1934vm_object_page_remove(vm_object_t object, vm_pindex_t start, vm_pindex_t end,
1935 boolean_t clean_only)
1936{
1937 vm_page_t p, next;
1938 int wirings;
1939
1940 VM_OBJECT_LOCK_ASSERT(object, MA_OWNED);
1941 if (object->resident_page_count == 0)
1942 goto skipmemq;
1943
1944 /*
1945 * Since physically-backed objects do not use managed pages, we can't
1946 * remove pages from the object (we must instead remove the page
1947 * references, and then destroy the object).
1948 */
1949 KASSERT(object->type != OBJT_PHYS || object == kernel_object ||
1950 object == kmem_object,
1951 ("attempt to remove pages from a physical object"));
1952
1953 vm_object_pip_add(object, 1);
1954again:
1955 if ((p = TAILQ_FIRST(&object->memq)) != NULL) {
1956 if (p->pindex < start) {
1957 p = vm_page_splay(start, object->root);
1958 if ((object->root = p)->pindex < start)
1959 p = TAILQ_NEXT(p, listq);
1960 }
1961 }
1962
1963 /*
1964 * Assert: the variable p is either (1) the page with the
1965 * least pindex greater than or equal to the parameter pindex
1966 * or (2) NULL.
1967 */
1968 for (;
1969 p != NULL && (p->pindex < end || end == 0);
1970 p = next) {
1971 next = TAILQ_NEXT(p, listq);
1972
1973 /*
1974 * If the page is wired for any reason besides the
1975 * existence of managed, wired mappings, then it cannot
1976 * be freed. For example, fictitious pages, which
1977 * represent device memory, are inherently wired and
1978 * cannot be freed. They can, however, be invalidated
1979 * if "clean_only" is FALSE.
1980 */
1981 vm_page_lock(p);
1982 vm_page_lock_queues();
1983 if ((wirings = p->wire_count) != 0 &&
1984 (wirings = pmap_page_wired_mappings(p)) != p->wire_count) {
1985 /* Fictitious pages do not have managed mappings. */
1986 if ((p->flags & PG_FICTITIOUS) == 0)
1987 pmap_remove_all(p);
1988 /* Account for removal of managed, wired mappings. */
1989 p->wire_count -= wirings;
1990 if (!clean_only) {
1991 p->valid = 0;
1992 vm_page_undirty(p);
1993 }
1994 vm_page_unlock_queues();
1995 vm_page_unlock(p);
1996 continue;
1997 }
1998 if (vm_page_sleep_if_busy(p, TRUE, "vmopar"))
1999 goto again;
2000 KASSERT((p->flags & PG_FICTITIOUS) == 0,
2001 ("vm_object_page_remove: page %p is fictitious", p));
2002 if (clean_only && p->valid) {
2003 pmap_remove_write(p);
2004 if (p->dirty) {
2005 vm_page_unlock_queues();
2006 vm_page_unlock(p);
2007 continue;
2008 }
2009 }
2010 pmap_remove_all(p);
2011 /* Account for removal of managed, wired mappings. */
2012 if (wirings != 0)
2013 p->wire_count -= wirings;
2014 vm_page_free(p);
2015 vm_page_unlock_queues();
2016 vm_page_unlock(p);
2017 }
2018 vm_object_pip_wakeup(object);
2019skipmemq:
2020 if (__predict_false(object->cache != NULL))
2021 vm_page_cache_free(object, start, end);
2022}
2023
2024/*
2025 * Populate the specified range of the object with valid pages. Returns
2026 * TRUE if the range is successfully populated and FALSE otherwise.
2027 *
2028 * Note: This function should be optimized to pass a larger array of
2029 * pages to vm_pager_get_pages() before it is applied to a non-
2030 * OBJT_DEVICE object.
2031 *
2032 * The object must be locked.
2033 */
2034boolean_t
2035vm_object_populate(vm_object_t object, vm_pindex_t start, vm_pindex_t end)
2036{
2037 vm_page_t m, ma[1];
2038 vm_pindex_t pindex;
2039 int rv;
2040
2041 VM_OBJECT_LOCK_ASSERT(object, MA_OWNED);
2042 for (pindex = start; pindex < end; pindex++) {
2043 m = vm_page_grab(object, pindex, VM_ALLOC_NORMAL |
2044 VM_ALLOC_RETRY);
2045 if (m->valid != VM_PAGE_BITS_ALL) {
2046 ma[0] = m;
2047 rv = vm_pager_get_pages(object, ma, 1, 0);
2048 m = vm_page_lookup(object, pindex);
2049 if (m == NULL)
2050 break;
2051 if (rv != VM_PAGER_OK) {
2052 vm_page_lock(m);
2053 vm_page_lock_queues();
2054 vm_page_free(m);
2055 vm_page_unlock_queues();
2056 vm_page_unlock(m);
2057 break;
2058 }
2059 }
2060 /*
2061 * Keep "m" busy because a subsequent iteration may unlock
2062 * the object.
2063 */
2064 }
2065 if (pindex > start) {
2066 m = vm_page_lookup(object, start);
2067 while (m != NULL && m->pindex < pindex) {
2068 vm_page_wakeup(m);
2069 m = TAILQ_NEXT(m, listq);
2070 }
2071 }
2072 return (pindex == end);
2073}
2074
2075/*
2076 * Routine: vm_object_coalesce
2077 * Function: Coalesces two objects backing up adjoining
2078 * regions of memory into a single object.
2079 *
2080 * returns TRUE if objects were combined.
2081 *
2082 * NOTE: Only works at the moment if the second object is NULL -
2083 * if it's not, which object do we lock first?
2084 *
2085 * Parameters:
2086 * prev_object First object to coalesce
2087 * prev_offset Offset into prev_object
2088 * prev_size Size of reference to prev_object
2089 * next_size Size of reference to the second object
2090 * reserved Indicator that extension region has
2091 * swap accounted for
2092 *
2093 * Conditions:
2094 * The object must *not* be locked.
2095 */
2096boolean_t
2097vm_object_coalesce(vm_object_t prev_object, vm_ooffset_t prev_offset,
2098 vm_size_t prev_size, vm_size_t next_size, boolean_t reserved)
2099{
2100 vm_pindex_t next_pindex;
2101
2102 if (prev_object == NULL)
2103 return (TRUE);
2104 VM_OBJECT_LOCK(prev_object);
2105 if (prev_object->type != OBJT_DEFAULT &&
2106 prev_object->type != OBJT_SWAP) {
2107 VM_OBJECT_UNLOCK(prev_object);
2108 return (FALSE);
2109 }
2110
2111 /*
2112 * Try to collapse the object first
2113 */
2114 vm_object_collapse(prev_object);
2115
2116 /*
2117 * Can't coalesce if: . more than one reference . paged out . shadows
2118 * another object . has a copy elsewhere (any of which mean that the
2119 * pages not mapped to prev_entry may be in use anyway)
2120 */
2121 if (prev_object->backing_object != NULL) {
2122 VM_OBJECT_UNLOCK(prev_object);
2123 return (FALSE);
2124 }
2125
2126 prev_size >>= PAGE_SHIFT;
2127 next_size >>= PAGE_SHIFT;
2128 next_pindex = OFF_TO_IDX(prev_offset) + prev_size;
2129
2130 if ((prev_object->ref_count > 1) &&
2131 (prev_object->size != next_pindex)) {
2132 VM_OBJECT_UNLOCK(prev_object);
2133 return (FALSE);
2134 }
2135
2136 /*
2137 * Account for the charge.
2138 */
2139 if (prev_object->uip != NULL) {
2140
2141 /*
2142 * If prev_object was charged, then this mapping,
2143 * althought not charged now, may become writable
2144 * later. Non-NULL uip in the object would prevent
2145 * swap reservation during enabling of the write
2146 * access, so reserve swap now. Failed reservation
2147 * cause allocation of the separate object for the map
2148 * entry, and swap reservation for this entry is
2149 * managed in appropriate time.
2150 */
2151 if (!reserved && !swap_reserve_by_uid(ptoa(next_size),
2152 prev_object->uip)) {
2153 return (FALSE);
2154 }
2155 prev_object->charge += ptoa(next_size);
2156 }
2157
2158 /*
2159 * Remove any pages that may still be in the object from a previous
2160 * deallocation.
2161 */
2162 if (next_pindex < prev_object->size) {
2163 vm_object_page_remove(prev_object,
2164 next_pindex,
2165 next_pindex + next_size, FALSE);
2166 if (prev_object->type == OBJT_SWAP)
2167 swap_pager_freespace(prev_object,
2168 next_pindex, next_size);
2169#if 0
2170 if (prev_object->uip != NULL) {
2171 KASSERT(prev_object->charge >=
2172 ptoa(prev_object->size - next_pindex),
2173 ("object %p overcharged 1 %jx %jx", prev_object,
2174 (uintmax_t)next_pindex, (uintmax_t)next_size));
2175 prev_object->charge -= ptoa(prev_object->size -
2176 next_pindex);
2177 }
2178#endif
2179 }
2180
2181 /*
2182 * Extend the object if necessary.
2183 */
2184 if (next_pindex + next_size > prev_object->size)
2185 prev_object->size = next_pindex + next_size;
2186
2187 VM_OBJECT_UNLOCK(prev_object);
2188 return (TRUE);
2189}
2190
2191void
2192vm_object_set_writeable_dirty(vm_object_t object)
2193{
2194
2195 VM_OBJECT_LOCK_ASSERT(object, MA_OWNED);
2196 if (object->type != OBJT_VNODE ||
2197 (object->flags & OBJ_MIGHTBEDIRTY) != 0)
2198 return;
2199 vm_object_set_flag(object, OBJ_MIGHTBEDIRTY);
2200}
2201
2202#include "opt_ddb.h"
2203#ifdef DDB
2204#include <sys/kernel.h>
2205
2206#include <sys/cons.h>
2207
2208#include <ddb/ddb.h>
2209
2210static int
2211_vm_object_in_map(vm_map_t map, vm_object_t object, vm_map_entry_t entry)
2212{
2213 vm_map_t tmpm;
2214 vm_map_entry_t tmpe;
2215 vm_object_t obj;
2216 int entcount;
2217
2218 if (map == 0)
2219 return 0;
2220
2221 if (entry == 0) {
2222 tmpe = map->header.next;
2223 entcount = map->nentries;
2224 while (entcount-- && (tmpe != &map->header)) {
2225 if (_vm_object_in_map(map, object, tmpe)) {
2226 return 1;
2227 }
2228 tmpe = tmpe->next;
2229 }
2230 } else if (entry->eflags & MAP_ENTRY_IS_SUB_MAP) {
2231 tmpm = entry->object.sub_map;
2232 tmpe = tmpm->header.next;
2233 entcount = tmpm->nentries;
2234 while (entcount-- && tmpe != &tmpm->header) {
2235 if (_vm_object_in_map(tmpm, object, tmpe)) {
2236 return 1;
2237 }
2238 tmpe = tmpe->next;
2239 }
2240 } else if ((obj = entry->object.vm_object) != NULL) {
2241 for (; obj; obj = obj->backing_object)
2242 if (obj == object) {
2243 return 1;
2244 }
2245 }
2246 return 0;
2247}
2248
2249static int
2250vm_object_in_map(vm_object_t object)
2251{
2252 struct proc *p;
2253
2254 /* sx_slock(&allproc_lock); */
2255 FOREACH_PROC_IN_SYSTEM(p) {
2256 if (!p->p_vmspace /* || (p->p_flag & (P_SYSTEM|P_WEXIT)) */)
2257 continue;
2258 if (_vm_object_in_map(&p->p_vmspace->vm_map, object, 0)) {
2259 /* sx_sunlock(&allproc_lock); */
2260 return 1;
2261 }
2262 }
2263 /* sx_sunlock(&allproc_lock); */
2264 if (_vm_object_in_map(kernel_map, object, 0))
2265 return 1;
2266 if (_vm_object_in_map(kmem_map, object, 0))
2267 return 1;
2268 if (_vm_object_in_map(pager_map, object, 0))
2269 return 1;
2270 if (_vm_object_in_map(buffer_map, object, 0))
2271 return 1;
2272 return 0;
2273}
2274
2275DB_SHOW_COMMAND(vmochk, vm_object_check)
2276{
2277 vm_object_t object;
2278
2279 /*
2280 * make sure that internal objs are in a map somewhere
2281 * and none have zero ref counts.
2282 */
2283 TAILQ_FOREACH(object, &vm_object_list, object_list) {
2284 if (object->handle == NULL &&
2285 (object->type == OBJT_DEFAULT || object->type == OBJT_SWAP)) {
2286 if (object->ref_count == 0) {
2287 db_printf("vmochk: internal obj has zero ref count: %ld\n",
2288 (long)object->size);
2289 }
2290 if (!vm_object_in_map(object)) {
2291 db_printf(
2292 "vmochk: internal obj is not in a map: "
2293 "ref: %d, size: %lu: 0x%lx, backing_object: %p\n",
2294 object->ref_count, (u_long)object->size,
2295 (u_long)object->size,
2296 (void *)object->backing_object);
2297 }
2298 }
2299 }
2300}
2301
2302/*
2303 * vm_object_print: [ debug ]
2304 */
2305DB_SHOW_COMMAND(object, vm_object_print_static)
2306{
2307 /* XXX convert args. */
2308 vm_object_t object = (vm_object_t)addr;
2309 boolean_t full = have_addr;
2310
2311 vm_page_t p;
2312
2313 /* XXX count is an (unused) arg. Avoid shadowing it. */
2314#define count was_count
2315
2316 int count;
2317
2318 if (object == NULL)
2319 return;
2320
2321 db_iprintf(
2322 "Object %p: type=%d, size=0x%jx, res=%d, ref=%d, flags=0x%x uip %d charge %jx\n",
2323 object, (int)object->type, (uintmax_t)object->size,
2324 object->resident_page_count, object->ref_count, object->flags,
2325 object->uip ? object->uip->ui_uid : -1, (uintmax_t)object->charge);
2326 db_iprintf(" sref=%d, backing_object(%d)=(%p)+0x%jx\n",
2327 object->shadow_count,
2328 object->backing_object ? object->backing_object->ref_count : 0,
2329 object->backing_object, (uintmax_t)object->backing_object_offset);
2330
2331 if (!full)
2332 return;
2333
2334 db_indent += 2;
2335 count = 0;
2336 TAILQ_FOREACH(p, &object->memq, listq) {
2337 if (count == 0)
2338 db_iprintf("memory:=");
2339 else if (count == 6) {
2340 db_printf("\n");
2341 db_iprintf(" ...");
2342 count = 0;
2343 } else
2344 db_printf(",");
2345 count++;
2346
2347 db_printf("(off=0x%jx,page=0x%jx)",
2348 (uintmax_t)p->pindex, (uintmax_t)VM_PAGE_TO_PHYS(p));
2349 }
2350 if (count != 0)
2351 db_printf("\n");
2352 db_indent -= 2;
2353}
2354
2355/* XXX. */
2356#undef count
2357
2358/* XXX need this non-static entry for calling from vm_map_print. */
2359void
2360vm_object_print(
2361 /* db_expr_t */ long addr,
2362 boolean_t have_addr,
2363 /* db_expr_t */ long count,
2364 char *modif)
2365{
2366 vm_object_print_static(addr, have_addr, count, modif);
2367}
2368
2369DB_SHOW_COMMAND(vmopag, vm_object_print_pages)
2370{
2371 vm_object_t object;
2372 vm_pindex_t fidx;
2373 vm_paddr_t pa;
2374 vm_page_t m, prev_m;
2375 int rcount, nl, c;
2376
2377 nl = 0;
2378 TAILQ_FOREACH(object, &vm_object_list, object_list) {
2379 db_printf("new object: %p\n", (void *)object);
2380 if (nl > 18) {
2381 c = cngetc();
2382 if (c != ' ')
2383 return;
2384 nl = 0;
2385 }
2386 nl++;
2387 rcount = 0;
2388 fidx = 0;
2389 pa = -1;
2390 TAILQ_FOREACH(m, &object->memq, listq) {
2391 if (m->pindex > 128)
2392 break;
2393 if ((prev_m = TAILQ_PREV(m, pglist, listq)) != NULL &&
2394 prev_m->pindex + 1 != m->pindex) {
2395 if (rcount) {
2396 db_printf(" index(%ld)run(%d)pa(0x%lx)\n",
2397 (long)fidx, rcount, (long)pa);
2398 if (nl > 18) {
2399 c = cngetc();
2400 if (c != ' ')
2401 return;
2402 nl = 0;
2403 }
2404 nl++;
2405 rcount = 0;
2406 }
2407 }
2408 if (rcount &&
2409 (VM_PAGE_TO_PHYS(m) == pa + rcount * PAGE_SIZE)) {
2410 ++rcount;
2411 continue;
2412 }
2413 if (rcount) {
2414 db_printf(" index(%ld)run(%d)pa(0x%lx)\n",
2415 (long)fidx, rcount, (long)pa);
2416 if (nl > 18) {
2417 c = cngetc();
2418 if (c != ' ')
2419 return;
2420 nl = 0;
2421 }
2422 nl++;
2423 }
2424 fidx = m->pindex;
2425 pa = VM_PAGE_TO_PHYS(m);
2426 rcount = 1;
2427 }
2428 if (rcount) {
2429 db_printf(" index(%ld)run(%d)pa(0x%lx)\n",
2430 (long)fidx, rcount, (long)pa);
2431 if (nl > 18) {
2432 c = cngetc();
2433 if (c != ' ')
2434 return;
2435 nl = 0;
2436 }
2437 nl++;
2438 }
2439 }
2440}
2441#endif /* DDB */