2 * Copyright (c) 1991, 1993
3 * The Regents of the University of California. All rights reserved.
5 * This code is derived from software contributed to Berkeley by
6 * The Mach Operating System project at Carnegie-Mellon University.
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted provided that the following conditions
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.
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
32 * from: @(#)vm_object.c 8.5 (Berkeley) 3/22/94
35 * Copyright (c) 1987, 1990 Carnegie-Mellon University.
36 * All rights reserved.
38 * Authors: Avadis Tevanian, Jr., Michael Wayne Young
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.
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.
50 * Carnegie Mellon requests users of this software to return to
52 * Software Distribution Coordinator or Software.Distribution@CS.CMU.EDU
53 * School of Computer Science
54 * Carnegie Mellon University
55 * Pittsburgh PA 15213-3890
57 * any improvements or extensions that they make and grant Carnegie the
58 * rights to redistribute these changes.
62 * Virtual memory object module.
65 #include <sys/cdefs.h>
66 __FBSDID("$FreeBSD$");
70 #include <sys/param.h>
71 #include <sys/systm.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>
86 #include <vm/vm_param.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>
99 #define EASY_SCAN_FACTOR 8
101 #define MSYNC_FLUSH_HARDSEQ 0x01
102 #define MSYNC_FLUSH_SOFTSEQ 0x02
105 * msync / VM object flushing optimizations
107 static int msync_flush_flags = MSYNC_FLUSH_HARDSEQ | MSYNC_FLUSH_SOFTSEQ;
108 SYSCTL_INT(_vm, OID_AUTO, msync_flush_flags, CTLFLAG_RW, &msync_flush_flags, 0,
109 "Enable sequential iteration optimization");
111 static int old_msync;
112 SYSCTL_INT(_vm, OID_AUTO, old_msync, CTLFLAG_RW, &old_msync, 0,
113 "Use old (insecure) msync behavior");
115 static void vm_object_qcollapse(vm_object_t object);
116 static int vm_object_page_collect_flush(vm_object_t object, vm_page_t p, int curgeneration, int pagerflags);
117 static void vm_object_vndeallocate(vm_object_t object);
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.
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.
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
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.
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
145 struct object_q vm_object_list;
146 struct mtx vm_object_list_mtx; /* lock for object list and count */
148 struct vm_object kernel_object_store;
149 struct vm_object kmem_object_store;
151 SYSCTL_NODE(_vm_stats, OID_AUTO, object, CTLFLAG_RD, 0, "VM object stats");
153 static long object_collapses;
154 SYSCTL_LONG(_vm_stats_object, OID_AUTO, collapses, CTLFLAG_RD,
155 &object_collapses, 0, "VM object collapses");
157 static long object_bypasses;
158 SYSCTL_LONG(_vm_stats_object, OID_AUTO, bypasses, CTLFLAG_RD,
159 &object_bypasses, 0, "VM object bypasses");
161 static uma_zone_t obj_zone;
163 static int vm_object_zinit(void *mem, int size, int flags);
166 static void vm_object_zdtor(void *mem, int size, void *arg);
169 vm_object_zdtor(void *mem, int size, void *arg)
173 object = (vm_object_t)mem;
174 KASSERT(TAILQ_EMPTY(&object->memq),
175 ("object %p has resident pages",
177 #if VM_NRESERVLEVEL > 0
178 KASSERT(LIST_EMPTY(&object->rvq),
179 ("object %p has reservations",
182 KASSERT(object->cache == NULL,
183 ("object %p has cached pages",
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));
198 vm_object_zinit(void *mem, int size, int flags)
202 object = (vm_object_t)mem;
203 bzero(&object->mtx, sizeof(object->mtx));
204 VM_OBJECT_LOCK_INIT(object, "standard object");
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;
214 _vm_object_allocate(objtype_t type, vm_pindex_t size, vm_object_t object)
217 TAILQ_INIT(&object->memq);
218 LIST_INIT(&object->shadow_head);
223 object->generation = 1;
224 object->ref_count = 1;
225 object->memattr = VM_MEMATTR_DEFAULT;
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);
238 object->cache = NULL;
240 mtx_lock(&vm_object_list_mtx);
241 TAILQ_INSERT_TAIL(&vm_object_list, object, object_list);
242 mtx_unlock(&vm_object_list_mtx);
248 * Initialize the VM objects module.
253 TAILQ_INIT(&vm_object_list);
254 mtx_init(&vm_object_list_mtx, "vm object_list", NULL, MTX_DEF);
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),
259 #if VM_NRESERVLEVEL > 0
260 kernel_object->flags |= OBJ_COLORED;
261 kernel_object->pg_color = (u_short)atop(VM_MIN_KERNEL_ADDRESS);
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),
267 #if VM_NRESERVLEVEL > 0
268 kmem_object->flags |= OBJ_COLORED;
269 kmem_object->pg_color = (u_short)atop(VM_MIN_KERNEL_ADDRESS);
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.
277 obj_zone = uma_zcreate("VM OBJECT", sizeof (struct vm_object), NULL,
283 vm_object_zinit, NULL, UMA_ALIGN_PTR, UMA_ZONE_VM|UMA_ZONE_NOFREE);
287 vm_object_clear_flag(vm_object_t object, u_short bits)
290 VM_OBJECT_LOCK_ASSERT(object, MA_OWNED);
291 object->flags &= ~bits;
295 * Sets the default memory attribute for the specified object. Pages
296 * that are allocated to this object are by default assigned this memory
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.
304 vm_object_set_memattr(vm_object_t object, vm_memattr_t memattr)
307 VM_OBJECT_LOCK_ASSERT(object, MA_OWNED);
308 switch (object->type) {
315 if (!TAILQ_EMPTY(&object->memq))
316 return (KERN_FAILURE);
319 return (KERN_INVALID_ARGUMENT);
321 object->memattr = memattr;
322 return (KERN_SUCCESS);
326 vm_object_pip_add(vm_object_t object, short i)
329 VM_OBJECT_LOCK_ASSERT(object, MA_OWNED);
330 object->paging_in_progress += i;
334 vm_object_pip_subtract(vm_object_t object, short i)
337 VM_OBJECT_LOCK_ASSERT(object, MA_OWNED);
338 object->paging_in_progress -= i;
342 vm_object_pip_wakeup(vm_object_t object)
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);
354 vm_object_pip_wakeupn(vm_object_t object, short i)
357 VM_OBJECT_LOCK_ASSERT(object, MA_OWNED);
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);
367 vm_object_pip_wait(vm_object_t object, char *waitid)
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);
378 * vm_object_allocate:
380 * Returns a new object with the given size.
383 vm_object_allocate(objtype_t type, vm_pindex_t size)
387 object = (vm_object_t)uma_zalloc(obj_zone, M_WAITOK);
388 _vm_object_allocate(type, size, object);
394 * vm_object_reference:
396 * Gets another reference to the given object. Note: OBJ_DEAD
397 * objects can be referenced during final cleaning.
400 vm_object_reference(vm_object_t object)
404 VM_OBJECT_LOCK(object);
405 vm_object_reference_locked(object);
406 VM_OBJECT_UNLOCK(object);
410 * vm_object_reference_locked:
412 * Gets another reference to the given object.
414 * The object must be locked.
417 vm_object_reference_locked(vm_object_t object)
421 VM_OBJECT_LOCK_ASSERT(object, MA_OWNED);
423 if (object->type == OBJT_VNODE) {
430 * Handle deallocating an object of type OBJT_VNODE.
433 vm_object_vndeallocate(vm_object_t object)
435 struct vnode *vp = (struct vnode *) object->handle;
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"));
443 if (object->ref_count == 0) {
444 vprint("vm_object_vndeallocate", vp);
445 panic("vm_object_vndeallocate: bad object reference count");
450 if (object->ref_count == 0) {
451 mp_fixme("Unlocked vflag access.");
452 vp->v_vflag &= ~VV_TEXT;
454 VM_OBJECT_UNLOCK(object);
456 * vrele may need a vop lock
462 * vm_object_deallocate:
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.
470 * No object may be locked.
473 vm_object_deallocate(vm_object_t object)
477 while (object != NULL) {
482 VM_OBJECT_LOCK(object);
483 if (object->type == OBJT_VNODE) {
484 struct vnode *vp = (struct vnode *) object->handle;
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
492 if (VFS_NEEDSGIANT(vp->v_mount) && !vfslocked) {
494 if (!mtx_trylock(&Giant)) {
495 VM_OBJECT_UNLOCK(object);
500 vm_object_vndeallocate(object);
501 VFS_UNLOCK_GIANT(vfslocked);
505 * This is to handle the case that the object
506 * changed type while we dropped its lock to
509 VFS_UNLOCK_GIANT(vfslocked);
511 KASSERT(object->ref_count != 0,
512 ("vm_object_deallocate: object deallocated too many times: %d", object->type));
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.
521 if (object->ref_count > 1) {
522 VM_OBJECT_UNLOCK(object);
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)) {
536 robject = LIST_FIRST(&object->shadow_head);
537 KASSERT(robject != NULL,
538 ("vm_object_deallocate: ref_count: %d, shadow_count: %d",
540 object->shadow_count));
541 if (!VM_OBJECT_TRYLOCK(robject)) {
543 * Avoid a potential deadlock.
546 VM_OBJECT_UNLOCK(object);
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.
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.
562 if ((robject->flags & OBJ_DEAD) == 0 &&
563 (robject->handle == NULL) &&
564 (robject->type == OBJT_DEFAULT ||
565 robject->type == OBJT_SWAP)) {
567 robject->ref_count++;
569 if (robject->paging_in_progress) {
570 VM_OBJECT_UNLOCK(object);
571 vm_object_pip_wait(robject,
573 temp = robject->backing_object;
574 if (object == temp) {
575 VM_OBJECT_LOCK(object);
578 } else if (object->paging_in_progress) {
579 VM_OBJECT_UNLOCK(robject);
580 object->flags |= OBJ_PIPWNT;
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);
591 VM_OBJECT_UNLOCK(object);
593 if (robject->ref_count == 1) {
594 robject->ref_count--;
599 vm_object_collapse(object);
600 VM_OBJECT_UNLOCK(object);
603 VM_OBJECT_UNLOCK(robject);
605 VM_OBJECT_UNLOCK(object);
609 temp = object->backing_object;
611 VM_OBJECT_LOCK(temp);
612 LIST_REMOVE(object, shadow_list);
613 temp->shadow_count--;
615 VM_OBJECT_UNLOCK(temp);
616 object->backing_object = NULL;
619 * Don't double-terminate, we could be in a termination
620 * recursion due to the terminate having to sync data
623 if ((object->flags & OBJ_DEAD) == 0)
624 vm_object_terminate(object);
626 VM_OBJECT_UNLOCK(object);
632 * vm_object_destroy removes the object from the global object list
633 * and frees the space for the object.
636 vm_object_destroy(vm_object_t object)
640 * Remove the object from the global object list.
642 mtx_lock(&vm_object_list_mtx);
643 TAILQ_REMOVE(&vm_object_list, object, object_list);
644 mtx_unlock(&vm_object_list_mtx);
647 * Release the allocation charge.
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",
654 swap_release_by_uid(object->charge, object->uip);
661 * Free the space for the object.
663 uma_zfree(obj_zone, object);
667 * vm_object_terminate actually destroys the specified object, freeing
668 * up all previously used resources.
670 * The object must be locked.
671 * This routine may block.
674 vm_object_terminate(vm_object_t object)
678 VM_OBJECT_LOCK_ASSERT(object, MA_OWNED);
681 * Make sure no one uses us.
683 vm_object_set_flag(object, OBJ_DEAD);
686 * wait for the pageout daemon to be done with the object
688 vm_object_pip_wait(object, "objtrm");
690 KASSERT(!object->paging_in_progress,
691 ("vm_object_terminate: pageout in progress"));
694 * Clean and free the pages, as appropriate. All references to the
695 * object are gone, so we don't need to lock it.
697 if (object->type == OBJT_VNODE) {
698 struct vnode *vp = (struct vnode *)object->handle;
701 * Clean pages and flush buffers.
703 vm_object_page_clean(object, 0, 0, OBJPC_SYNC);
704 VM_OBJECT_UNLOCK(object);
706 vinvalbuf(vp, V_SAVE, 0, 0);
708 VM_OBJECT_LOCK(object);
711 KASSERT(object->ref_count == 0,
712 ("vm_object_terminate: object with references, ref_count=%d",
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.
720 vm_page_lock_queues();
721 while ((p = TAILQ_FIRST(&object->memq)) != NULL) {
722 KASSERT(!p->busy && (p->oflags & VPO_BUSY) == 0,
723 ("vm_object_terminate: freeing busy page %p "
724 "p->busy = %d, p->oflags %x\n", p, p->busy, p->oflags));
725 if (p->wire_count == 0) {
732 vm_page_unlock_queues();
734 #if VM_NRESERVLEVEL > 0
735 if (__predict_false(!LIST_EMPTY(&object->rvq)))
736 vm_reserv_break_all(object);
738 if (__predict_false(object->cache != NULL))
739 vm_page_cache_free(object, 0, 0);
742 * Let the pager know object is dead.
744 vm_pager_deallocate(object);
745 VM_OBJECT_UNLOCK(object);
747 vm_object_destroy(object);
751 * vm_object_page_clean
753 * Clean all dirty pages in the specified range of object. Leaves page
754 * on whatever queue it is currently on. If NOSYNC is set then do not
755 * write out pages with VPO_NOSYNC set (originally comes from MAP_NOSYNC),
756 * leaving the object dirty.
758 * When stuffing pages asynchronously, allow clustering. XXX we need a
759 * synchronous clustering mode implementation.
761 * Odd semantics: if start == end, we clean everything.
763 * The object must be locked.
766 vm_object_page_clean(vm_object_t object, vm_pindex_t start, vm_pindex_t end, int flags)
769 vm_pindex_t tstart, tend;
775 VM_OBJECT_LOCK_ASSERT(object, MA_OWNED);
776 if ((object->flags & OBJ_MIGHTBEDIRTY) == 0)
778 KASSERT(object->type == OBJT_VNODE, ("Not a vnode object"));
780 pagerflags = (flags & (OBJPC_SYNC | OBJPC_INVAL)) ? VM_PAGER_PUT_SYNC : VM_PAGER_CLUSTER_OK;
781 pagerflags |= (flags & OBJPC_INVAL) ? VM_PAGER_PUT_INVAL : 0;
783 vm_object_set_flag(object, OBJ_CLEANING);
792 vm_page_lock_queues();
794 * If the caller is smart and only msync()s a range he knows is
795 * dirty, we may be able to avoid an object scan. This results in
796 * a phenominal improvement in performance. We cannot do this
797 * as a matter of course because the object may be huge - e.g.
798 * the size might be in the gigabytes or terrabytes.
800 if (msync_flush_flags & MSYNC_FLUSH_HARDSEQ) {
805 scanreset = object->resident_page_count / EASY_SCAN_FACTOR;
808 pagerflags |= VM_PAGER_IGNORE_CLEANCHK;
810 scanlimit = scanreset;
812 while (tscan < tend) {
813 curgeneration = object->generation;
814 p = vm_page_lookup(object, tscan);
815 if (p == NULL || p->valid == 0) {
816 if (--scanlimit == 0)
821 vm_page_test_dirty(p);
823 if (--scanlimit == 0)
829 * If we have been asked to skip nosync pages and
830 * this is a nosync page, we can't continue.
832 if ((flags & OBJPC_NOSYNC) && (p->oflags & VPO_NOSYNC)) {
833 if (--scanlimit == 0)
838 scanlimit = scanreset;
841 * This returns 0 if it was unable to busy the first
842 * page (i.e. had to sleep).
844 tscan += vm_object_page_collect_flush(object, p, curgeneration, pagerflags);
848 * If everything was dirty and we flushed it successfully,
849 * and the requested range is not the entire object, we
850 * don't have to mess with CLEANCHK or MIGHTBEDIRTY and can
851 * return immediately.
853 if (tscan >= tend && (tstart || tend < object->size)) {
854 vm_page_unlock_queues();
855 vm_object_clear_flag(object, OBJ_CLEANING);
858 pagerflags &= ~VM_PAGER_IGNORE_CLEANCHK;
862 * Generally set CLEANCHK interlock and make the page read-only so
863 * we can then clear the object flags.
865 * However, if this is a nosync mmap then the object is likely to
866 * stay dirty so do not mess with the page and do not clear the
870 TAILQ_FOREACH(p, &object->memq, listq) {
871 p->oflags |= VPO_CLEANCHK;
872 if ((flags & OBJPC_NOSYNC) && (p->oflags & VPO_NOSYNC))
875 pmap_remove_write(p);
878 if (clearobjflags && (tstart == 0) && (tend == object->size))
879 vm_object_clear_flag(object, OBJ_MIGHTBEDIRTY);
882 curgeneration = object->generation;
884 for (p = TAILQ_FIRST(&object->memq); p; p = np) {
887 np = TAILQ_NEXT(p, listq);
891 if ((p->oflags & VPO_CLEANCHK) == 0 ||
892 (pi < tstart) || (pi >= tend) ||
894 p->oflags &= ~VPO_CLEANCHK;
898 vm_page_test_dirty(p);
900 p->oflags &= ~VPO_CLEANCHK;
905 * If we have been asked to skip nosync pages and this is a
906 * nosync page, skip it. Note that the object flags were
907 * not cleared in this case so we do not have to set them.
909 if ((flags & OBJPC_NOSYNC) && (p->oflags & VPO_NOSYNC)) {
910 p->oflags &= ~VPO_CLEANCHK;
914 n = vm_object_page_collect_flush(object, p,
915 curgeneration, pagerflags);
919 if (object->generation != curgeneration)
923 * Try to optimize the next page. If we can't we pick up
924 * our (random) scan where we left off.
926 if (msync_flush_flags & MSYNC_FLUSH_SOFTSEQ) {
927 if ((p = vm_page_lookup(object, pi + n)) != NULL)
931 vm_page_unlock_queues();
933 VOP_FSYNC(vp, (pagerflags & VM_PAGER_PUT_SYNC)?MNT_WAIT:0, curproc);
936 vm_object_clear_flag(object, OBJ_CLEANING);
941 vm_object_page_collect_flush(vm_object_t object, vm_page_t p, int curgeneration, int pagerflags)
949 vm_page_t maf[vm_pageout_page_count];
950 vm_page_t mab[vm_pageout_page_count];
951 vm_page_t ma[vm_pageout_page_count];
953 mtx_assert(&vm_page_queue_mtx, MA_OWNED);
955 while (vm_page_sleep_if_busy(p, TRUE, "vpcwai")) {
956 vm_page_lock_queues();
957 if (object->generation != curgeneration) {
962 for(i = 1; i < vm_pageout_page_count; i++) {
965 if ((tp = vm_page_lookup(object, pi + i)) != NULL) {
966 if ((tp->oflags & VPO_BUSY) ||
967 ((pagerflags & VM_PAGER_IGNORE_CLEANCHK) == 0 &&
968 (tp->oflags & VPO_CLEANCHK) == 0) ||
971 vm_page_test_dirty(tp);
972 if (tp->dirty == 0) {
973 tp->oflags &= ~VPO_CLEANCHK;
984 chkb = vm_pageout_page_count - maxf;
986 for(i = 1; i < chkb;i++) {
989 if ((tp = vm_page_lookup(object, pi - i)) != NULL) {
990 if ((tp->oflags & VPO_BUSY) ||
991 ((pagerflags & VM_PAGER_IGNORE_CLEANCHK) == 0 &&
992 (tp->oflags & VPO_CLEANCHK) == 0) ||
995 vm_page_test_dirty(tp);
996 if (tp->dirty == 0) {
997 tp->oflags &= ~VPO_CLEANCHK;
1008 for(i = 0; i < maxb; i++) {
1009 int index = (maxb - i) - 1;
1011 ma[index]->oflags &= ~VPO_CLEANCHK;
1013 p->oflags &= ~VPO_CLEANCHK;
1015 for(i = 0; i < maxf; i++) {
1016 int index = (maxb + i) + 1;
1018 ma[index]->oflags &= ~VPO_CLEANCHK;
1020 runlen = maxb + maxf + 1;
1022 vm_pageout_flush(ma, runlen, pagerflags);
1023 for (i = 0; i < runlen; i++) {
1025 pmap_remove_write(ma[i]);
1026 ma[i]->oflags |= VPO_CLEANCHK;
1029 * maxf will end up being the actual number of pages
1030 * we wrote out contiguously, non-inclusive of the
1031 * first page. We do not count look-behind pages.
1033 if (i >= maxb + 1 && (maxf > i - maxb - 1))
1034 maxf = i - maxb - 1;
1041 * Note that there is absolutely no sense in writing out
1042 * anonymous objects, so we track down the vnode object
1044 * We invalidate (remove) all pages from the address space
1045 * for semantic correctness.
1047 * Note: certain anonymous maps, such as MAP_NOSYNC maps,
1048 * may start out with a NULL object.
1051 vm_object_sync(vm_object_t object, vm_ooffset_t offset, vm_size_t size,
1052 boolean_t syncio, boolean_t invalidate)
1054 vm_object_t backing_object;
1061 VM_OBJECT_LOCK(object);
1062 while ((backing_object = object->backing_object) != NULL) {
1063 VM_OBJECT_LOCK(backing_object);
1064 offset += object->backing_object_offset;
1065 VM_OBJECT_UNLOCK(object);
1066 object = backing_object;
1067 if (object->size < OFF_TO_IDX(offset + size))
1068 size = IDX_TO_OFF(object->size) - offset;
1071 * Flush pages if writing is allowed, invalidate them
1072 * if invalidation requested. Pages undergoing I/O
1073 * will be ignored by vm_object_page_remove().
1075 * We cannot lock the vnode and then wait for paging
1076 * to complete without deadlocking against vm_fault.
1077 * Instead we simply call vm_object_page_remove() and
1078 * allow it to block internally on a page-by-page
1079 * basis when it encounters pages undergoing async
1082 if (object->type == OBJT_VNODE &&
1083 (object->flags & OBJ_MIGHTBEDIRTY) != 0) {
1085 vp = object->handle;
1086 VM_OBJECT_UNLOCK(object);
1087 (void) vn_start_write(vp, &mp, V_WAIT);
1088 vfslocked = VFS_LOCK_GIANT(vp->v_mount);
1089 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
1090 flags = (syncio || invalidate) ? OBJPC_SYNC : 0;
1091 flags |= invalidate ? OBJPC_INVAL : 0;
1092 VM_OBJECT_LOCK(object);
1093 vm_object_page_clean(object,
1095 OFF_TO_IDX(offset + size + PAGE_MASK),
1097 VM_OBJECT_UNLOCK(object);
1099 VFS_UNLOCK_GIANT(vfslocked);
1100 vn_finished_write(mp);
1101 VM_OBJECT_LOCK(object);
1103 if ((object->type == OBJT_VNODE ||
1104 object->type == OBJT_DEVICE) && invalidate) {
1106 purge = old_msync || (object->type == OBJT_DEVICE);
1107 vm_object_page_remove(object,
1109 OFF_TO_IDX(offset + size + PAGE_MASK),
1110 purge ? FALSE : TRUE);
1112 VM_OBJECT_UNLOCK(object);
1116 * vm_object_madvise:
1118 * Implements the madvise function at the object/page level.
1120 * MADV_WILLNEED (any object)
1122 * Activate the specified pages if they are resident.
1124 * MADV_DONTNEED (any object)
1126 * Deactivate the specified pages if they are resident.
1128 * MADV_FREE (OBJT_DEFAULT/OBJT_SWAP objects,
1129 * OBJ_ONEMAPPING only)
1131 * Deactivate and clean the specified pages if they are
1132 * resident. This permits the process to reuse the pages
1133 * without faulting or the kernel to reclaim the pages
1137 vm_object_madvise(vm_object_t object, vm_pindex_t pindex, int count, int advise)
1139 vm_pindex_t end, tpindex;
1140 vm_object_t backing_object, tobject;
1145 VM_OBJECT_LOCK(object);
1146 end = pindex + count;
1148 * Locate and adjust resident pages
1150 for (; pindex < end; pindex += 1) {
1156 * MADV_FREE only operates on OBJT_DEFAULT or OBJT_SWAP pages
1157 * and those pages must be OBJ_ONEMAPPING.
1159 if (advise == MADV_FREE) {
1160 if ((tobject->type != OBJT_DEFAULT &&
1161 tobject->type != OBJT_SWAP) ||
1162 (tobject->flags & OBJ_ONEMAPPING) == 0) {
1163 goto unlock_tobject;
1165 } else if (tobject->type == OBJT_PHYS)
1166 goto unlock_tobject;
1167 m = vm_page_lookup(tobject, tpindex);
1168 if (m == NULL && advise == MADV_WILLNEED) {
1170 * If the page is cached, reactivate it.
1172 m = vm_page_alloc(tobject, tpindex, VM_ALLOC_IFCACHED |
1177 * There may be swap even if there is no backing page
1179 if (advise == MADV_FREE && tobject->type == OBJT_SWAP)
1180 swap_pager_freespace(tobject, tpindex, 1);
1184 backing_object = tobject->backing_object;
1185 if (backing_object == NULL)
1186 goto unlock_tobject;
1187 VM_OBJECT_LOCK(backing_object);
1188 tpindex += OFF_TO_IDX(tobject->backing_object_offset);
1189 if (tobject != object)
1190 VM_OBJECT_UNLOCK(tobject);
1191 tobject = backing_object;
1193 } else if (m->valid != VM_PAGE_BITS_ALL)
1194 goto unlock_tobject;
1196 * If the page is not in a normal state, skip it.
1198 vm_page_lock_queues();
1199 if (m->hold_count != 0 || m->wire_count != 0) {
1200 vm_page_unlock_queues();
1201 goto unlock_tobject;
1203 if ((m->oflags & VPO_BUSY) || m->busy) {
1204 if (advise == MADV_WILLNEED)
1206 * Reference the page before unlocking and
1207 * sleeping so that the page daemon is less
1208 * likely to reclaim it.
1210 vm_page_flag_set(m, PG_REFERENCED);
1211 vm_page_unlock_queues();
1212 if (object != tobject)
1213 VM_OBJECT_UNLOCK(object);
1214 m->oflags |= VPO_WANTED;
1215 msleep(m, VM_OBJECT_MTX(tobject), PDROP | PVM, "madvpo",
1217 VM_OBJECT_LOCK(object);
1220 if (advise == MADV_WILLNEED) {
1221 vm_page_activate(m);
1222 } else if (advise == MADV_DONTNEED) {
1223 vm_page_dontneed(m);
1224 } else if (advise == MADV_FREE) {
1226 * Mark the page clean. This will allow the page
1227 * to be freed up by the system. However, such pages
1228 * are often reused quickly by malloc()/free()
1229 * so we do not do anything that would cause
1230 * a page fault if we can help it.
1232 * Specifically, we do not try to actually free
1233 * the page now nor do we try to put it in the
1234 * cache (which would cause a page fault on reuse).
1236 * But we do make the page is freeable as we
1237 * can without actually taking the step of unmapping
1240 pmap_clear_modify(m);
1243 vm_page_dontneed(m);
1245 vm_page_unlock_queues();
1246 if (advise == MADV_FREE && tobject->type == OBJT_SWAP)
1247 swap_pager_freespace(tobject, tpindex, 1);
1249 if (tobject != object)
1250 VM_OBJECT_UNLOCK(tobject);
1252 VM_OBJECT_UNLOCK(object);
1258 * Create a new object which is backed by the
1259 * specified existing object range. The source
1260 * object reference is deallocated.
1262 * The new object and offset into that object
1263 * are returned in the source parameters.
1267 vm_object_t *object, /* IN/OUT */
1268 vm_ooffset_t *offset, /* IN/OUT */
1277 * Don't create the new object if the old object isn't shared.
1279 if (source != NULL) {
1280 VM_OBJECT_LOCK(source);
1281 if (source->ref_count == 1 &&
1282 source->handle == NULL &&
1283 (source->type == OBJT_DEFAULT ||
1284 source->type == OBJT_SWAP)) {
1285 VM_OBJECT_UNLOCK(source);
1288 VM_OBJECT_UNLOCK(source);
1292 * Allocate a new object with the given length.
1294 result = vm_object_allocate(OBJT_DEFAULT, length);
1297 * The new object shadows the source object, adding a reference to it.
1298 * Our caller changes his reference to point to the new object,
1299 * removing a reference to the source object. Net result: no change
1300 * of reference count.
1302 * Try to optimize the result object's page color when shadowing
1303 * in order to maintain page coloring consistency in the combined
1306 result->backing_object = source;
1308 * Store the offset into the source object, and fix up the offset into
1311 result->backing_object_offset = *offset;
1312 if (source != NULL) {
1313 VM_OBJECT_LOCK(source);
1314 LIST_INSERT_HEAD(&source->shadow_head, result, shadow_list);
1315 source->shadow_count++;
1316 source->generation++;
1317 #if VM_NRESERVLEVEL > 0
1318 result->flags |= source->flags & OBJ_COLORED;
1319 result->pg_color = (source->pg_color + OFF_TO_IDX(*offset)) &
1320 ((1 << (VM_NFREEORDER - 1)) - 1);
1322 VM_OBJECT_UNLOCK(source);
1327 * Return the new things
1336 * Split the pages in a map entry into a new object. This affords
1337 * easier removal of unused pages, and keeps object inheritance from
1338 * being a negative impact on memory usage.
1341 vm_object_split(vm_map_entry_t entry)
1343 vm_page_t m, m_next;
1344 vm_object_t orig_object, new_object, source;
1345 vm_pindex_t idx, offidxstart;
1348 orig_object = entry->object.vm_object;
1349 if (orig_object->type != OBJT_DEFAULT && orig_object->type != OBJT_SWAP)
1351 if (orig_object->ref_count <= 1)
1353 VM_OBJECT_UNLOCK(orig_object);
1355 offidxstart = OFF_TO_IDX(entry->offset);
1356 size = atop(entry->end - entry->start);
1359 * If swap_pager_copy() is later called, it will convert new_object
1360 * into a swap object.
1362 new_object = vm_object_allocate(OBJT_DEFAULT, size);
1365 * At this point, the new object is still private, so the order in
1366 * which the original and new objects are locked does not matter.
1368 VM_OBJECT_LOCK(new_object);
1369 VM_OBJECT_LOCK(orig_object);
1370 source = orig_object->backing_object;
1371 if (source != NULL) {
1372 VM_OBJECT_LOCK(source);
1373 if ((source->flags & OBJ_DEAD) != 0) {
1374 VM_OBJECT_UNLOCK(source);
1375 VM_OBJECT_UNLOCK(orig_object);
1376 VM_OBJECT_UNLOCK(new_object);
1377 vm_object_deallocate(new_object);
1378 VM_OBJECT_LOCK(orig_object);
1381 LIST_INSERT_HEAD(&source->shadow_head,
1382 new_object, shadow_list);
1383 source->shadow_count++;
1384 source->generation++;
1385 vm_object_reference_locked(source); /* for new_object */
1386 vm_object_clear_flag(source, OBJ_ONEMAPPING);
1387 VM_OBJECT_UNLOCK(source);
1388 new_object->backing_object_offset =
1389 orig_object->backing_object_offset + entry->offset;
1390 new_object->backing_object = source;
1392 if (orig_object->uip != NULL) {
1393 new_object->uip = orig_object->uip;
1394 uihold(orig_object->uip);
1395 new_object->charge = ptoa(size);
1396 KASSERT(orig_object->charge >= ptoa(size),
1397 ("orig_object->charge < 0"));
1398 orig_object->charge -= ptoa(size);
1401 if ((m = TAILQ_FIRST(&orig_object->memq)) != NULL) {
1402 if (m->pindex < offidxstart) {
1403 m = vm_page_splay(offidxstart, orig_object->root);
1404 if ((orig_object->root = m)->pindex < offidxstart)
1405 m = TAILQ_NEXT(m, listq);
1408 vm_page_lock_queues();
1409 for (; m != NULL && (idx = m->pindex - offidxstart) < size;
1411 m_next = TAILQ_NEXT(m, listq);
1414 * We must wait for pending I/O to complete before we can
1417 * We do not have to VM_PROT_NONE the page as mappings should
1418 * not be changed by this operation.
1420 if ((m->oflags & VPO_BUSY) || m->busy) {
1421 vm_page_unlock_queues();
1422 VM_OBJECT_UNLOCK(new_object);
1423 m->oflags |= VPO_WANTED;
1424 msleep(m, VM_OBJECT_MTX(orig_object), PVM, "spltwt", 0);
1425 VM_OBJECT_LOCK(new_object);
1428 vm_page_rename(m, new_object, idx);
1429 /* page automatically made dirty by rename and cache handled */
1432 vm_page_unlock_queues();
1433 if (orig_object->type == OBJT_SWAP) {
1435 * swap_pager_copy() can sleep, in which case the orig_object's
1436 * and new_object's locks are released and reacquired.
1438 swap_pager_copy(orig_object, new_object, offidxstart, 0);
1441 * Transfer any cached pages from orig_object to new_object.
1443 if (__predict_false(orig_object->cache != NULL))
1444 vm_page_cache_transfer(orig_object, offidxstart,
1447 VM_OBJECT_UNLOCK(orig_object);
1448 TAILQ_FOREACH(m, &new_object->memq, listq)
1450 VM_OBJECT_UNLOCK(new_object);
1451 entry->object.vm_object = new_object;
1452 entry->offset = 0LL;
1453 vm_object_deallocate(orig_object);
1454 VM_OBJECT_LOCK(new_object);
1457 #define OBSC_TEST_ALL_SHADOWED 0x0001
1458 #define OBSC_COLLAPSE_NOWAIT 0x0002
1459 #define OBSC_COLLAPSE_WAIT 0x0004
1462 vm_object_backing_scan(vm_object_t object, int op)
1466 vm_object_t backing_object;
1467 vm_pindex_t backing_offset_index;
1469 VM_OBJECT_LOCK_ASSERT(object, MA_OWNED);
1470 VM_OBJECT_LOCK_ASSERT(object->backing_object, MA_OWNED);
1472 backing_object = object->backing_object;
1473 backing_offset_index = OFF_TO_IDX(object->backing_object_offset);
1476 * Initial conditions
1478 if (op & OBSC_TEST_ALL_SHADOWED) {
1480 * We do not want to have to test for the existence of cache
1481 * or swap pages in the backing object. XXX but with the
1482 * new swapper this would be pretty easy to do.
1484 * XXX what about anonymous MAP_SHARED memory that hasn't
1485 * been ZFOD faulted yet? If we do not test for this, the
1486 * shadow test may succeed! XXX
1488 if (backing_object->type != OBJT_DEFAULT) {
1492 if (op & OBSC_COLLAPSE_WAIT) {
1493 vm_object_set_flag(backing_object, OBJ_DEAD);
1499 p = TAILQ_FIRST(&backing_object->memq);
1501 vm_page_t next = TAILQ_NEXT(p, listq);
1502 vm_pindex_t new_pindex = p->pindex - backing_offset_index;
1504 if (op & OBSC_TEST_ALL_SHADOWED) {
1508 * Ignore pages outside the parent object's range
1509 * and outside the parent object's mapping of the
1512 * note that we do not busy the backing object's
1516 p->pindex < backing_offset_index ||
1517 new_pindex >= object->size
1524 * See if the parent has the page or if the parent's
1525 * object pager has the page. If the parent has the
1526 * page but the page is not valid, the parent's
1527 * object pager must have the page.
1529 * If this fails, the parent does not completely shadow
1530 * the object and we might as well give up now.
1533 pp = vm_page_lookup(object, new_pindex);
1535 (pp == NULL || pp->valid == 0) &&
1536 !vm_pager_has_page(object, new_pindex, NULL, NULL)
1544 * Check for busy page
1546 if (op & (OBSC_COLLAPSE_WAIT | OBSC_COLLAPSE_NOWAIT)) {
1549 if (op & OBSC_COLLAPSE_NOWAIT) {
1550 if ((p->oflags & VPO_BUSY) ||
1556 } else if (op & OBSC_COLLAPSE_WAIT) {
1557 if ((p->oflags & VPO_BUSY) || p->busy) {
1558 VM_OBJECT_UNLOCK(object);
1559 p->oflags |= VPO_WANTED;
1560 msleep(p, VM_OBJECT_MTX(backing_object),
1561 PDROP | PVM, "vmocol", 0);
1562 VM_OBJECT_LOCK(object);
1563 VM_OBJECT_LOCK(backing_object);
1565 * If we slept, anything could have
1566 * happened. Since the object is
1567 * marked dead, the backing offset
1568 * should not have changed so we
1569 * just restart our scan.
1571 p = TAILQ_FIRST(&backing_object->memq);
1577 p->object == backing_object,
1578 ("vm_object_backing_scan: object mismatch")
1582 * Destroy any associated swap
1584 if (backing_object->type == OBJT_SWAP) {
1585 swap_pager_freespace(
1593 p->pindex < backing_offset_index ||
1594 new_pindex >= object->size
1597 * Page is out of the parent object's range, we
1598 * can simply destroy it.
1600 vm_page_lock_queues();
1601 KASSERT(!pmap_page_is_mapped(p),
1602 ("freeing mapped page %p", p));
1603 if (p->wire_count == 0)
1607 vm_page_unlock_queues();
1612 pp = vm_page_lookup(object, new_pindex);
1615 vm_pager_has_page(object, new_pindex, NULL, NULL)
1618 * page already exists in parent OR swap exists
1619 * for this location in the parent. Destroy
1620 * the original page from the backing object.
1622 * Leave the parent's page alone
1624 vm_page_lock_queues();
1625 KASSERT(!pmap_page_is_mapped(p),
1626 ("freeing mapped page %p", p));
1627 if (p->wire_count == 0)
1631 vm_page_unlock_queues();
1636 #if VM_NRESERVLEVEL > 0
1638 * Rename the reservation.
1640 vm_reserv_rename(p, object, backing_object,
1641 backing_offset_index);
1645 * Page does not exist in parent, rename the
1646 * page from the backing object to the main object.
1648 * If the page was mapped to a process, it can remain
1649 * mapped through the rename.
1651 vm_page_lock_queues();
1652 vm_page_rename(p, object, new_pindex);
1653 vm_page_unlock_queues();
1654 /* page automatically made dirty by rename */
1663 * this version of collapse allows the operation to occur earlier and
1664 * when paging_in_progress is true for an object... This is not a complete
1665 * operation, but should plug 99.9% of the rest of the leaks.
1668 vm_object_qcollapse(vm_object_t object)
1670 vm_object_t backing_object = object->backing_object;
1672 VM_OBJECT_LOCK_ASSERT(object, MA_OWNED);
1673 VM_OBJECT_LOCK_ASSERT(backing_object, MA_OWNED);
1675 if (backing_object->ref_count != 1)
1678 vm_object_backing_scan(object, OBSC_COLLAPSE_NOWAIT);
1682 * vm_object_collapse:
1684 * Collapse an object with the object backing it.
1685 * Pages in the backing object are moved into the
1686 * parent, and the backing object is deallocated.
1689 vm_object_collapse(vm_object_t object)
1691 VM_OBJECT_LOCK_ASSERT(object, MA_OWNED);
1694 vm_object_t backing_object;
1697 * Verify that the conditions are right for collapse:
1699 * The object exists and the backing object exists.
1701 if ((backing_object = object->backing_object) == NULL)
1705 * we check the backing object first, because it is most likely
1708 VM_OBJECT_LOCK(backing_object);
1709 if (backing_object->handle != NULL ||
1710 (backing_object->type != OBJT_DEFAULT &&
1711 backing_object->type != OBJT_SWAP) ||
1712 (backing_object->flags & OBJ_DEAD) ||
1713 object->handle != NULL ||
1714 (object->type != OBJT_DEFAULT &&
1715 object->type != OBJT_SWAP) ||
1716 (object->flags & OBJ_DEAD)) {
1717 VM_OBJECT_UNLOCK(backing_object);
1722 object->paging_in_progress != 0 ||
1723 backing_object->paging_in_progress != 0
1725 vm_object_qcollapse(object);
1726 VM_OBJECT_UNLOCK(backing_object);
1730 * We know that we can either collapse the backing object (if
1731 * the parent is the only reference to it) or (perhaps) have
1732 * the parent bypass the object if the parent happens to shadow
1733 * all the resident pages in the entire backing object.
1735 * This is ignoring pager-backed pages such as swap pages.
1736 * vm_object_backing_scan fails the shadowing test in this
1739 if (backing_object->ref_count == 1) {
1741 * If there is exactly one reference to the backing
1742 * object, we can collapse it into the parent.
1744 vm_object_backing_scan(object, OBSC_COLLAPSE_WAIT);
1746 #if VM_NRESERVLEVEL > 0
1748 * Break any reservations from backing_object.
1750 if (__predict_false(!LIST_EMPTY(&backing_object->rvq)))
1751 vm_reserv_break_all(backing_object);
1755 * Move the pager from backing_object to object.
1757 if (backing_object->type == OBJT_SWAP) {
1759 * swap_pager_copy() can sleep, in which case
1760 * the backing_object's and object's locks are
1761 * released and reacquired.
1766 OFF_TO_IDX(object->backing_object_offset), TRUE);
1769 * Free any cached pages from backing_object.
1771 if (__predict_false(backing_object->cache != NULL))
1772 vm_page_cache_free(backing_object, 0, 0);
1775 * Object now shadows whatever backing_object did.
1776 * Note that the reference to
1777 * backing_object->backing_object moves from within
1778 * backing_object to within object.
1780 LIST_REMOVE(object, shadow_list);
1781 backing_object->shadow_count--;
1782 backing_object->generation++;
1783 if (backing_object->backing_object) {
1784 VM_OBJECT_LOCK(backing_object->backing_object);
1785 LIST_REMOVE(backing_object, shadow_list);
1787 &backing_object->backing_object->shadow_head,
1788 object, shadow_list);
1790 * The shadow_count has not changed.
1792 backing_object->backing_object->generation++;
1793 VM_OBJECT_UNLOCK(backing_object->backing_object);
1795 object->backing_object = backing_object->backing_object;
1796 object->backing_object_offset +=
1797 backing_object->backing_object_offset;
1800 * Discard backing_object.
1802 * Since the backing object has no pages, no pager left,
1803 * and no object references within it, all that is
1804 * necessary is to dispose of it.
1806 KASSERT(backing_object->ref_count == 1, (
1807 "backing_object %p was somehow re-referenced during collapse!",
1809 VM_OBJECT_UNLOCK(backing_object);
1810 vm_object_destroy(backing_object);
1814 vm_object_t new_backing_object;
1817 * If we do not entirely shadow the backing object,
1818 * there is nothing we can do so we give up.
1820 if (object->resident_page_count != object->size &&
1821 vm_object_backing_scan(object,
1822 OBSC_TEST_ALL_SHADOWED) == 0) {
1823 VM_OBJECT_UNLOCK(backing_object);
1828 * Make the parent shadow the next object in the
1829 * chain. Deallocating backing_object will not remove
1830 * it, since its reference count is at least 2.
1832 LIST_REMOVE(object, shadow_list);
1833 backing_object->shadow_count--;
1834 backing_object->generation++;
1836 new_backing_object = backing_object->backing_object;
1837 if ((object->backing_object = new_backing_object) != NULL) {
1838 VM_OBJECT_LOCK(new_backing_object);
1840 &new_backing_object->shadow_head,
1844 new_backing_object->shadow_count++;
1845 new_backing_object->generation++;
1846 vm_object_reference_locked(new_backing_object);
1847 VM_OBJECT_UNLOCK(new_backing_object);
1848 object->backing_object_offset +=
1849 backing_object->backing_object_offset;
1853 * Drop the reference count on backing_object. Since
1854 * its ref_count was at least 2, it will not vanish.
1856 backing_object->ref_count--;
1857 VM_OBJECT_UNLOCK(backing_object);
1862 * Try again with this object's new backing object.
1868 * vm_object_page_remove:
1870 * For the given object, either frees or invalidates each of the
1871 * specified pages. In general, a page is freed. However, if a
1872 * page is wired for any reason other than the existence of a
1873 * managed, wired mapping, then it may be invalidated but not
1874 * removed from the object. Pages are specified by the given
1875 * range ["start", "end") and Boolean "clean_only". As a
1876 * special case, if "end" is zero, then the range extends from
1877 * "start" to the end of the object. If "clean_only" is TRUE,
1878 * then only the non-dirty pages within the specified range are
1881 * In general, this operation should only be performed on objects
1882 * that contain managed pages. There are two exceptions. First,
1883 * it may be performed on the kernel and kmem objects. Second,
1884 * it may be used by msync(..., MS_INVALIDATE) to invalidate
1885 * device-backed pages. In both of these cases, "clean_only"
1888 * The object must be locked.
1891 vm_object_page_remove(vm_object_t object, vm_pindex_t start, vm_pindex_t end,
1892 boolean_t clean_only)
1897 VM_OBJECT_LOCK_ASSERT(object, MA_OWNED);
1898 if (object->resident_page_count == 0)
1902 * Since physically-backed objects do not use managed pages, we can't
1903 * remove pages from the object (we must instead remove the page
1904 * references, and then destroy the object).
1906 KASSERT(object->type != OBJT_PHYS || object == kernel_object ||
1907 object == kmem_object,
1908 ("attempt to remove pages from a physical object"));
1910 vm_object_pip_add(object, 1);
1912 if ((p = TAILQ_FIRST(&object->memq)) != NULL) {
1913 if (p->pindex < start) {
1914 p = vm_page_splay(start, object->root);
1915 if ((object->root = p)->pindex < start)
1916 p = TAILQ_NEXT(p, listq);
1919 vm_page_lock_queues();
1921 * Assert: the variable p is either (1) the page with the
1922 * least pindex greater than or equal to the parameter pindex
1926 p != NULL && (p->pindex < end || end == 0);
1928 next = TAILQ_NEXT(p, listq);
1931 * If the page is wired for any reason besides the
1932 * existence of managed, wired mappings, then it cannot
1933 * be freed. For example, fictitious pages, which
1934 * represent device memory, are inherently wired and
1935 * cannot be freed. They can, however, be invalidated
1936 * if "clean_only" is FALSE.
1938 if ((wirings = p->wire_count) != 0 &&
1939 (wirings = pmap_page_wired_mappings(p)) != p->wire_count) {
1940 /* Fictitious pages do not have managed mappings. */
1941 if ((p->flags & PG_FICTITIOUS) == 0)
1943 /* Account for removal of managed, wired mappings. */
1944 p->wire_count -= wirings;
1951 if (vm_page_sleep_if_busy(p, TRUE, "vmopar"))
1953 KASSERT((p->flags & PG_FICTITIOUS) == 0,
1954 ("vm_object_page_remove: page %p is fictitious", p));
1955 if (clean_only && p->valid) {
1956 pmap_remove_write(p);
1961 /* Account for removal of managed, wired mappings. */
1963 p->wire_count -= wirings;
1966 vm_page_unlock_queues();
1967 vm_object_pip_wakeup(object);
1969 if (__predict_false(object->cache != NULL))
1970 vm_page_cache_free(object, start, end);
1974 * Populate the specified range of the object with valid pages. Returns
1975 * TRUE if the range is successfully populated and FALSE otherwise.
1977 * Note: This function should be optimized to pass a larger array of
1978 * pages to vm_pager_get_pages() before it is applied to a non-
1979 * OBJT_DEVICE object.
1981 * The object must be locked.
1984 vm_object_populate(vm_object_t object, vm_pindex_t start, vm_pindex_t end)
1990 VM_OBJECT_LOCK_ASSERT(object, MA_OWNED);
1991 for (pindex = start; pindex < end; pindex++) {
1992 m = vm_page_grab(object, pindex, VM_ALLOC_NORMAL |
1994 if (m->valid != VM_PAGE_BITS_ALL) {
1996 rv = vm_pager_get_pages(object, ma, 1, 0);
1997 m = vm_page_lookup(object, pindex);
2000 if (rv != VM_PAGER_OK) {
2001 vm_page_lock_queues();
2003 vm_page_unlock_queues();
2008 * Keep "m" busy because a subsequent iteration may unlock
2012 if (pindex > start) {
2013 m = vm_page_lookup(object, start);
2014 while (m != NULL && m->pindex < pindex) {
2016 m = TAILQ_NEXT(m, listq);
2019 return (pindex == end);
2023 * Routine: vm_object_coalesce
2024 * Function: Coalesces two objects backing up adjoining
2025 * regions of memory into a single object.
2027 * returns TRUE if objects were combined.
2029 * NOTE: Only works at the moment if the second object is NULL -
2030 * if it's not, which object do we lock first?
2033 * prev_object First object to coalesce
2034 * prev_offset Offset into prev_object
2035 * prev_size Size of reference to prev_object
2036 * next_size Size of reference to the second object
2037 * reserved Indicator that extension region has
2038 * swap accounted for
2041 * The object must *not* be locked.
2044 vm_object_coalesce(vm_object_t prev_object, vm_ooffset_t prev_offset,
2045 vm_size_t prev_size, vm_size_t next_size, boolean_t reserved)
2047 vm_pindex_t next_pindex;
2049 if (prev_object == NULL)
2051 VM_OBJECT_LOCK(prev_object);
2052 if (prev_object->type != OBJT_DEFAULT &&
2053 prev_object->type != OBJT_SWAP) {
2054 VM_OBJECT_UNLOCK(prev_object);
2059 * Try to collapse the object first
2061 vm_object_collapse(prev_object);
2064 * Can't coalesce if: . more than one reference . paged out . shadows
2065 * another object . has a copy elsewhere (any of which mean that the
2066 * pages not mapped to prev_entry may be in use anyway)
2068 if (prev_object->backing_object != NULL) {
2069 VM_OBJECT_UNLOCK(prev_object);
2073 prev_size >>= PAGE_SHIFT;
2074 next_size >>= PAGE_SHIFT;
2075 next_pindex = OFF_TO_IDX(prev_offset) + prev_size;
2077 if ((prev_object->ref_count > 1) &&
2078 (prev_object->size != next_pindex)) {
2079 VM_OBJECT_UNLOCK(prev_object);
2084 * Account for the charge.
2086 if (prev_object->uip != NULL) {
2089 * If prev_object was charged, then this mapping,
2090 * althought not charged now, may become writable
2091 * later. Non-NULL uip in the object would prevent
2092 * swap reservation during enabling of the write
2093 * access, so reserve swap now. Failed reservation
2094 * cause allocation of the separate object for the map
2095 * entry, and swap reservation for this entry is
2096 * managed in appropriate time.
2098 if (!reserved && !swap_reserve_by_uid(ptoa(next_size),
2099 prev_object->uip)) {
2102 prev_object->charge += ptoa(next_size);
2106 * Remove any pages that may still be in the object from a previous
2109 if (next_pindex < prev_object->size) {
2110 vm_object_page_remove(prev_object,
2112 next_pindex + next_size, FALSE);
2113 if (prev_object->type == OBJT_SWAP)
2114 swap_pager_freespace(prev_object,
2115 next_pindex, next_size);
2117 if (prev_object->uip != NULL) {
2118 KASSERT(prev_object->charge >=
2119 ptoa(prev_object->size - next_pindex),
2120 ("object %p overcharged 1 %jx %jx", prev_object,
2121 (uintmax_t)next_pindex, (uintmax_t)next_size));
2122 prev_object->charge -= ptoa(prev_object->size -
2129 * Extend the object if necessary.
2131 if (next_pindex + next_size > prev_object->size)
2132 prev_object->size = next_pindex + next_size;
2134 VM_OBJECT_UNLOCK(prev_object);
2139 vm_object_set_writeable_dirty(vm_object_t object)
2142 VM_OBJECT_LOCK_ASSERT(object, MA_OWNED);
2143 if (object->type != OBJT_VNODE ||
2144 (object->flags & OBJ_MIGHTBEDIRTY) != 0)
2146 vm_object_set_flag(object, OBJ_MIGHTBEDIRTY);
2149 #include "opt_ddb.h"
2151 #include <sys/kernel.h>
2153 #include <sys/cons.h>
2155 #include <ddb/ddb.h>
2158 _vm_object_in_map(vm_map_t map, vm_object_t object, vm_map_entry_t entry)
2161 vm_map_entry_t tmpe;
2169 tmpe = map->header.next;
2170 entcount = map->nentries;
2171 while (entcount-- && (tmpe != &map->header)) {
2172 if (_vm_object_in_map(map, object, tmpe)) {
2177 } else if (entry->eflags & MAP_ENTRY_IS_SUB_MAP) {
2178 tmpm = entry->object.sub_map;
2179 tmpe = tmpm->header.next;
2180 entcount = tmpm->nentries;
2181 while (entcount-- && tmpe != &tmpm->header) {
2182 if (_vm_object_in_map(tmpm, object, tmpe)) {
2187 } else if ((obj = entry->object.vm_object) != NULL) {
2188 for (; obj; obj = obj->backing_object)
2189 if (obj == object) {
2197 vm_object_in_map(vm_object_t object)
2201 /* sx_slock(&allproc_lock); */
2202 FOREACH_PROC_IN_SYSTEM(p) {
2203 if (!p->p_vmspace /* || (p->p_flag & (P_SYSTEM|P_WEXIT)) */)
2205 if (_vm_object_in_map(&p->p_vmspace->vm_map, object, 0)) {
2206 /* sx_sunlock(&allproc_lock); */
2210 /* sx_sunlock(&allproc_lock); */
2211 if (_vm_object_in_map(kernel_map, object, 0))
2213 if (_vm_object_in_map(kmem_map, object, 0))
2215 if (_vm_object_in_map(pager_map, object, 0))
2217 if (_vm_object_in_map(buffer_map, object, 0))
2222 DB_SHOW_COMMAND(vmochk, vm_object_check)
2227 * make sure that internal objs are in a map somewhere
2228 * and none have zero ref counts.
2230 TAILQ_FOREACH(object, &vm_object_list, object_list) {
2231 if (object->handle == NULL &&
2232 (object->type == OBJT_DEFAULT || object->type == OBJT_SWAP)) {
2233 if (object->ref_count == 0) {
2234 db_printf("vmochk: internal obj has zero ref count: %ld\n",
2235 (long)object->size);
2237 if (!vm_object_in_map(object)) {
2239 "vmochk: internal obj is not in a map: "
2240 "ref: %d, size: %lu: 0x%lx, backing_object: %p\n",
2241 object->ref_count, (u_long)object->size,
2242 (u_long)object->size,
2243 (void *)object->backing_object);
2250 * vm_object_print: [ debug ]
2252 DB_SHOW_COMMAND(object, vm_object_print_static)
2254 /* XXX convert args. */
2255 vm_object_t object = (vm_object_t)addr;
2256 boolean_t full = have_addr;
2260 /* XXX count is an (unused) arg. Avoid shadowing it. */
2261 #define count was_count
2269 "Object %p: type=%d, size=0x%jx, res=%d, ref=%d, flags=0x%x uip %d charge %jx\n",
2270 object, (int)object->type, (uintmax_t)object->size,
2271 object->resident_page_count, object->ref_count, object->flags,
2272 object->uip ? object->uip->ui_uid : -1, (uintmax_t)object->charge);
2273 db_iprintf(" sref=%d, backing_object(%d)=(%p)+0x%jx\n",
2274 object->shadow_count,
2275 object->backing_object ? object->backing_object->ref_count : 0,
2276 object->backing_object, (uintmax_t)object->backing_object_offset);
2283 TAILQ_FOREACH(p, &object->memq, listq) {
2285 db_iprintf("memory:=");
2286 else if (count == 6) {
2294 db_printf("(off=0x%jx,page=0x%jx)",
2295 (uintmax_t)p->pindex, (uintmax_t)VM_PAGE_TO_PHYS(p));
2305 /* XXX need this non-static entry for calling from vm_map_print. */
2308 /* db_expr_t */ long addr,
2309 boolean_t have_addr,
2310 /* db_expr_t */ long count,
2313 vm_object_print_static(addr, have_addr, count, modif);
2316 DB_SHOW_COMMAND(vmopag, vm_object_print_pages)
2321 vm_page_t m, prev_m;
2325 TAILQ_FOREACH(object, &vm_object_list, object_list) {
2326 db_printf("new object: %p\n", (void *)object);
2337 TAILQ_FOREACH(m, &object->memq, listq) {
2338 if (m->pindex > 128)
2340 if ((prev_m = TAILQ_PREV(m, pglist, listq)) != NULL &&
2341 prev_m->pindex + 1 != m->pindex) {
2343 db_printf(" index(%ld)run(%d)pa(0x%lx)\n",
2344 (long)fidx, rcount, (long)pa);
2356 (VM_PAGE_TO_PHYS(m) == pa + rcount * PAGE_SIZE)) {
2361 db_printf(" index(%ld)run(%d)pa(0x%lx)\n",
2362 (long)fidx, rcount, (long)pa);
2372 pa = VM_PAGE_TO_PHYS(m);
2376 db_printf(" index(%ld)run(%d)pa(0x%lx)\n",
2377 (long)fidx, rcount, (long)pa);