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>
100 SYSCTL_INT(_vm, OID_AUTO, old_msync, CTLFLAG_RW, &old_msync, 0,
101 "Use old (insecure) msync behavior");
103 static int vm_object_page_collect_flush(vm_object_t object, vm_page_t p,
104 int pagerflags, int flags, int *clearobjflags);
105 static boolean_t vm_object_page_remove_write(vm_page_t p, int flags,
107 static void vm_object_qcollapse(vm_object_t object);
108 static void vm_object_vndeallocate(vm_object_t object);
111 * Virtual memory objects maintain the actual data
112 * associated with allocated virtual memory. A given
113 * page of memory exists within exactly one object.
115 * An object is only deallocated when all "references"
116 * are given up. Only one "reference" to a given
117 * region of an object should be writeable.
119 * Associated with each object is a list of all resident
120 * memory pages belonging to that object; this list is
121 * maintained by the "vm_page" module, and locked by the object's
124 * Each object also records a "pager" routine which is
125 * used to retrieve (and store) pages to the proper backing
126 * storage. In addition, objects may be backed by other
127 * objects from which they were virtual-copied.
129 * The only items within the object structure which are
130 * modified after time of creation are:
131 * reference count locked by object's lock
132 * pager routine locked by object's lock
136 struct object_q vm_object_list;
137 struct mtx vm_object_list_mtx; /* lock for object list and count */
139 struct vm_object kernel_object_store;
140 struct vm_object kmem_object_store;
142 SYSCTL_NODE(_vm_stats, OID_AUTO, object, CTLFLAG_RD, 0, "VM object stats");
144 static long object_collapses;
145 SYSCTL_LONG(_vm_stats_object, OID_AUTO, collapses, CTLFLAG_RD,
146 &object_collapses, 0, "VM object collapses");
148 static long object_bypasses;
149 SYSCTL_LONG(_vm_stats_object, OID_AUTO, bypasses, CTLFLAG_RD,
150 &object_bypasses, 0, "VM object bypasses");
152 static uma_zone_t obj_zone;
154 static int vm_object_zinit(void *mem, int size, int flags);
157 static void vm_object_zdtor(void *mem, int size, void *arg);
160 vm_object_zdtor(void *mem, int size, void *arg)
164 object = (vm_object_t)mem;
165 KASSERT(TAILQ_EMPTY(&object->memq),
166 ("object %p has resident pages",
168 #if VM_NRESERVLEVEL > 0
169 KASSERT(LIST_EMPTY(&object->rvq),
170 ("object %p has reservations",
173 KASSERT(object->cache == NULL,
174 ("object %p has cached pages",
176 KASSERT(object->paging_in_progress == 0,
177 ("object %p paging_in_progress = %d",
178 object, object->paging_in_progress));
179 KASSERT(object->resident_page_count == 0,
180 ("object %p resident_page_count = %d",
181 object, object->resident_page_count));
182 KASSERT(object->shadow_count == 0,
183 ("object %p shadow_count = %d",
184 object, object->shadow_count));
189 vm_object_zinit(void *mem, int size, int flags)
193 object = (vm_object_t)mem;
194 bzero(&object->mtx, sizeof(object->mtx));
195 VM_OBJECT_LOCK_INIT(object, "standard object");
197 /* These are true for any object that has been freed */
198 object->paging_in_progress = 0;
199 object->resident_page_count = 0;
200 object->shadow_count = 0;
205 _vm_object_allocate(objtype_t type, vm_pindex_t size, vm_object_t object)
208 TAILQ_INIT(&object->memq);
209 LIST_INIT(&object->shadow_head);
214 object->generation = 1;
215 object->ref_count = 1;
216 object->memattr = VM_MEMATTR_DEFAULT;
220 if ((object->type == OBJT_DEFAULT) || (object->type == OBJT_SWAP))
221 object->flags = OBJ_ONEMAPPING;
222 object->pg_color = 0;
223 object->handle = NULL;
224 object->backing_object = NULL;
225 object->backing_object_offset = (vm_ooffset_t) 0;
226 #if VM_NRESERVLEVEL > 0
227 LIST_INIT(&object->rvq);
229 object->cache = NULL;
231 mtx_lock(&vm_object_list_mtx);
232 TAILQ_INSERT_TAIL(&vm_object_list, object, object_list);
233 mtx_unlock(&vm_object_list_mtx);
239 * Initialize the VM objects module.
244 TAILQ_INIT(&vm_object_list);
245 mtx_init(&vm_object_list_mtx, "vm object_list", NULL, MTX_DEF);
247 VM_OBJECT_LOCK_INIT(kernel_object, "kernel object");
248 _vm_object_allocate(OBJT_PHYS, OFF_TO_IDX(VM_MAX_KERNEL_ADDRESS - VM_MIN_KERNEL_ADDRESS),
250 #if VM_NRESERVLEVEL > 0
251 kernel_object->flags |= OBJ_COLORED;
252 kernel_object->pg_color = (u_short)atop(VM_MIN_KERNEL_ADDRESS);
255 VM_OBJECT_LOCK_INIT(kmem_object, "kmem object");
256 _vm_object_allocate(OBJT_PHYS, OFF_TO_IDX(VM_MAX_KERNEL_ADDRESS - VM_MIN_KERNEL_ADDRESS),
258 #if VM_NRESERVLEVEL > 0
259 kmem_object->flags |= OBJ_COLORED;
260 kmem_object->pg_color = (u_short)atop(VM_MIN_KERNEL_ADDRESS);
264 * The lock portion of struct vm_object must be type stable due
265 * to vm_pageout_fallback_object_lock locking a vm object
266 * without holding any references to it.
268 obj_zone = uma_zcreate("VM OBJECT", sizeof (struct vm_object), NULL,
274 vm_object_zinit, NULL, UMA_ALIGN_PTR, UMA_ZONE_VM|UMA_ZONE_NOFREE);
278 vm_object_clear_flag(vm_object_t object, u_short bits)
281 VM_OBJECT_LOCK_ASSERT(object, MA_OWNED);
282 object->flags &= ~bits;
286 * Sets the default memory attribute for the specified object. Pages
287 * that are allocated to this object are by default assigned this memory
290 * Presently, this function must be called before any pages are allocated
291 * to the object. In the future, this requirement may be relaxed for
292 * "default" and "swap" objects.
295 vm_object_set_memattr(vm_object_t object, vm_memattr_t memattr)
298 VM_OBJECT_LOCK_ASSERT(object, MA_OWNED);
299 switch (object->type) {
306 if (!TAILQ_EMPTY(&object->memq))
307 return (KERN_FAILURE);
310 return (KERN_INVALID_ARGUMENT);
312 object->memattr = memattr;
313 return (KERN_SUCCESS);
317 vm_object_pip_add(vm_object_t object, short i)
320 VM_OBJECT_LOCK_ASSERT(object, MA_OWNED);
321 object->paging_in_progress += i;
325 vm_object_pip_subtract(vm_object_t object, short i)
328 VM_OBJECT_LOCK_ASSERT(object, MA_OWNED);
329 object->paging_in_progress -= i;
333 vm_object_pip_wakeup(vm_object_t object)
336 VM_OBJECT_LOCK_ASSERT(object, MA_OWNED);
337 object->paging_in_progress--;
338 if ((object->flags & OBJ_PIPWNT) && object->paging_in_progress == 0) {
339 vm_object_clear_flag(object, OBJ_PIPWNT);
345 vm_object_pip_wakeupn(vm_object_t object, short i)
348 VM_OBJECT_LOCK_ASSERT(object, MA_OWNED);
350 object->paging_in_progress -= i;
351 if ((object->flags & OBJ_PIPWNT) && object->paging_in_progress == 0) {
352 vm_object_clear_flag(object, OBJ_PIPWNT);
358 vm_object_pip_wait(vm_object_t object, char *waitid)
361 VM_OBJECT_LOCK_ASSERT(object, MA_OWNED);
362 while (object->paging_in_progress) {
363 object->flags |= OBJ_PIPWNT;
364 msleep(object, VM_OBJECT_MTX(object), PVM, waitid, 0);
369 * vm_object_allocate:
371 * Returns a new object with the given size.
374 vm_object_allocate(objtype_t type, vm_pindex_t size)
378 object = (vm_object_t)uma_zalloc(obj_zone, M_WAITOK);
379 _vm_object_allocate(type, size, object);
385 * vm_object_reference:
387 * Gets another reference to the given object. Note: OBJ_DEAD
388 * objects can be referenced during final cleaning.
391 vm_object_reference(vm_object_t object)
395 VM_OBJECT_LOCK(object);
396 vm_object_reference_locked(object);
397 VM_OBJECT_UNLOCK(object);
401 * vm_object_reference_locked:
403 * Gets another reference to the given object.
405 * The object must be locked.
408 vm_object_reference_locked(vm_object_t object)
412 VM_OBJECT_LOCK_ASSERT(object, MA_OWNED);
414 if (object->type == OBJT_VNODE) {
421 * Handle deallocating an object of type OBJT_VNODE.
424 vm_object_vndeallocate(vm_object_t object)
426 struct vnode *vp = (struct vnode *) object->handle;
428 VFS_ASSERT_GIANT(vp->v_mount);
429 VM_OBJECT_LOCK_ASSERT(object, MA_OWNED);
430 KASSERT(object->type == OBJT_VNODE,
431 ("vm_object_vndeallocate: not a vnode object"));
432 KASSERT(vp != NULL, ("vm_object_vndeallocate: missing vp"));
434 if (object->ref_count == 0) {
435 vprint("vm_object_vndeallocate", vp);
436 panic("vm_object_vndeallocate: bad object reference count");
440 if (object->ref_count > 1) {
442 VM_OBJECT_UNLOCK(object);
443 /* vrele may need the vnode lock. */
446 VM_OBJECT_UNLOCK(object);
447 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
448 VM_OBJECT_LOCK(object);
450 if (object->ref_count == 0)
451 vp->v_vflag &= ~VV_TEXT;
452 VM_OBJECT_UNLOCK(object);
458 * vm_object_deallocate:
460 * Release a reference to the specified object,
461 * gained either through a vm_object_allocate
462 * or a vm_object_reference call. When all references
463 * are gone, storage associated with this object
464 * may be relinquished.
466 * No object may be locked.
469 vm_object_deallocate(vm_object_t object)
473 while (object != NULL) {
478 VM_OBJECT_LOCK(object);
479 if (object->type == OBJT_VNODE) {
480 struct vnode *vp = (struct vnode *) object->handle;
483 * Conditionally acquire Giant for a vnode-backed
484 * object. We have to be careful since the type of
485 * a vnode object can change while the object is
488 if (VFS_NEEDSGIANT(vp->v_mount) && !vfslocked) {
490 if (!mtx_trylock(&Giant)) {
491 VM_OBJECT_UNLOCK(object);
496 vm_object_vndeallocate(object);
497 VFS_UNLOCK_GIANT(vfslocked);
501 * This is to handle the case that the object
502 * changed type while we dropped its lock to
505 VFS_UNLOCK_GIANT(vfslocked);
507 KASSERT(object->ref_count != 0,
508 ("vm_object_deallocate: object deallocated too many times: %d", object->type));
511 * If the reference count goes to 0 we start calling
512 * vm_object_terminate() on the object chain.
513 * A ref count of 1 may be a special case depending on the
514 * shadow count being 0 or 1.
517 if (object->ref_count > 1) {
518 VM_OBJECT_UNLOCK(object);
520 } else if (object->ref_count == 1) {
521 if (object->shadow_count == 0 &&
522 object->handle == NULL &&
523 (object->type == OBJT_DEFAULT ||
524 object->type == OBJT_SWAP)) {
525 vm_object_set_flag(object, OBJ_ONEMAPPING);
526 } else if ((object->shadow_count == 1) &&
527 (object->handle == NULL) &&
528 (object->type == OBJT_DEFAULT ||
529 object->type == OBJT_SWAP)) {
532 robject = LIST_FIRST(&object->shadow_head);
533 KASSERT(robject != NULL,
534 ("vm_object_deallocate: ref_count: %d, shadow_count: %d",
536 object->shadow_count));
537 if (!VM_OBJECT_TRYLOCK(robject)) {
539 * Avoid a potential deadlock.
542 VM_OBJECT_UNLOCK(object);
544 * More likely than not the thread
545 * holding robject's lock has lower
546 * priority than the current thread.
547 * Let the lower priority thread run.
553 * Collapse object into its shadow unless its
554 * shadow is dead. In that case, object will
555 * be deallocated by the thread that is
556 * deallocating its shadow.
558 if ((robject->flags & OBJ_DEAD) == 0 &&
559 (robject->handle == NULL) &&
560 (robject->type == OBJT_DEFAULT ||
561 robject->type == OBJT_SWAP)) {
563 robject->ref_count++;
565 if (robject->paging_in_progress) {
566 VM_OBJECT_UNLOCK(object);
567 vm_object_pip_wait(robject,
569 temp = robject->backing_object;
570 if (object == temp) {
571 VM_OBJECT_LOCK(object);
574 } else if (object->paging_in_progress) {
575 VM_OBJECT_UNLOCK(robject);
576 object->flags |= OBJ_PIPWNT;
578 VM_OBJECT_MTX(object),
579 PDROP | PVM, "objde2", 0);
580 VM_OBJECT_LOCK(robject);
581 temp = robject->backing_object;
582 if (object == temp) {
583 VM_OBJECT_LOCK(object);
587 VM_OBJECT_UNLOCK(object);
589 if (robject->ref_count == 1) {
590 robject->ref_count--;
595 vm_object_collapse(object);
596 VM_OBJECT_UNLOCK(object);
599 VM_OBJECT_UNLOCK(robject);
601 VM_OBJECT_UNLOCK(object);
605 temp = object->backing_object;
607 VM_OBJECT_LOCK(temp);
608 LIST_REMOVE(object, shadow_list);
609 temp->shadow_count--;
610 VM_OBJECT_UNLOCK(temp);
611 object->backing_object = NULL;
614 * Don't double-terminate, we could be in a termination
615 * recursion due to the terminate having to sync data
618 if ((object->flags & OBJ_DEAD) == 0)
619 vm_object_terminate(object);
621 VM_OBJECT_UNLOCK(object);
627 * vm_object_destroy removes the object from the global object list
628 * and frees the space for the object.
631 vm_object_destroy(vm_object_t object)
635 * Remove the object from the global object list.
637 mtx_lock(&vm_object_list_mtx);
638 TAILQ_REMOVE(&vm_object_list, object, object_list);
639 mtx_unlock(&vm_object_list_mtx);
642 * Release the allocation charge.
644 if (object->cred != NULL) {
645 KASSERT(object->type == OBJT_DEFAULT ||
646 object->type == OBJT_SWAP,
647 ("vm_object_terminate: non-swap obj %p has cred",
649 swap_release_by_cred(object->charge, object->cred);
651 crfree(object->cred);
656 * Free the space for the object.
658 uma_zfree(obj_zone, object);
662 * vm_object_terminate actually destroys the specified object, freeing
663 * up all previously used resources.
665 * The object must be locked.
666 * This routine may block.
669 vm_object_terminate(vm_object_t object)
673 VM_OBJECT_LOCK_ASSERT(object, MA_OWNED);
676 * Make sure no one uses us.
678 vm_object_set_flag(object, OBJ_DEAD);
681 * wait for the pageout daemon to be done with the object
683 vm_object_pip_wait(object, "objtrm");
685 KASSERT(!object->paging_in_progress,
686 ("vm_object_terminate: pageout in progress"));
689 * Clean and free the pages, as appropriate. All references to the
690 * object are gone, so we don't need to lock it.
692 if (object->type == OBJT_VNODE) {
693 struct vnode *vp = (struct vnode *)object->handle;
696 * Clean pages and flush buffers.
698 vm_object_page_clean(object, 0, 0, OBJPC_SYNC);
699 VM_OBJECT_UNLOCK(object);
701 vinvalbuf(vp, V_SAVE, 0, 0);
703 VM_OBJECT_LOCK(object);
706 KASSERT(object->ref_count == 0,
707 ("vm_object_terminate: object with references, ref_count=%d",
711 * Free any remaining pageable pages. This also removes them from the
712 * paging queues. However, don't free wired pages, just remove them
713 * from the object. Rather than incrementally removing each page from
714 * the object, the page and object are reset to any empty state.
716 TAILQ_FOREACH_SAFE(p, &object->memq, listq, p_next) {
717 KASSERT(!p->busy && (p->oflags & VPO_BUSY) == 0,
718 ("vm_object_terminate: freeing busy page %p", p));
721 * Optimize the page's removal from the object by resetting
722 * its "object" field. Specifically, if the page is not
723 * wired, then the effect of this assignment is that
724 * vm_page_free()'s call to vm_page_remove() will return
725 * immediately without modifying the page or the object.
728 if (p->wire_count == 0) {
730 PCPU_INC(cnt.v_pfree);
735 * If the object contained any pages, then reset it to an empty state.
736 * None of the object's fields, including "resident_page_count", were
737 * modified by the preceding loop.
739 if (object->resident_page_count != 0) {
741 TAILQ_INIT(&object->memq);
742 object->resident_page_count = 0;
743 if (object->type == OBJT_VNODE)
744 vdrop(object->handle);
747 #if VM_NRESERVLEVEL > 0
748 if (__predict_false(!LIST_EMPTY(&object->rvq)))
749 vm_reserv_break_all(object);
751 if (__predict_false(object->cache != NULL))
752 vm_page_cache_free(object, 0, 0);
755 * Let the pager know object is dead.
757 vm_pager_deallocate(object);
758 VM_OBJECT_UNLOCK(object);
760 vm_object_destroy(object);
764 * Make the page read-only so that we can clear the object flags. However, if
765 * this is a nosync mmap then the object is likely to stay dirty so do not
766 * mess with the page and do not clear the object flags. Returns TRUE if the
767 * page should be flushed, and FALSE otherwise.
770 vm_object_page_remove_write(vm_page_t p, int flags, int *clearobjflags)
774 * If we have been asked to skip nosync pages and this is a
775 * nosync page, skip it. Note that the object flags were not
776 * cleared in this case so we do not have to set them.
778 if ((flags & OBJPC_NOSYNC) != 0 && (p->oflags & VPO_NOSYNC) != 0) {
782 pmap_remove_write(p);
783 return (p->dirty != 0);
788 * vm_object_page_clean
790 * Clean all dirty pages in the specified range of object. Leaves page
791 * on whatever queue it is currently on. If NOSYNC is set then do not
792 * write out pages with VPO_NOSYNC set (originally comes from MAP_NOSYNC),
793 * leaving the object dirty.
795 * When stuffing pages asynchronously, allow clustering. XXX we need a
796 * synchronous clustering mode implementation.
798 * Odd semantics: if start == end, we clean everything.
800 * The object must be locked.
803 vm_object_page_clean(vm_object_t object, vm_ooffset_t start, vm_ooffset_t end,
807 vm_pindex_t pi, tend, tstart;
808 int clearobjflags, curgeneration, n, pagerflags;
810 mtx_assert(&vm_page_queue_mtx, MA_NOTOWNED);
811 VM_OBJECT_LOCK_ASSERT(object, MA_OWNED);
812 KASSERT(object->type == OBJT_VNODE, ("Not a vnode object"));
813 if ((object->flags & OBJ_MIGHTBEDIRTY) == 0 ||
814 object->resident_page_count == 0)
817 pagerflags = (flags & (OBJPC_SYNC | OBJPC_INVAL)) != 0 ?
818 VM_PAGER_PUT_SYNC : VM_PAGER_CLUSTER_OK;
819 pagerflags |= (flags & OBJPC_INVAL) != 0 ? VM_PAGER_PUT_INVAL : 0;
821 tstart = OFF_TO_IDX(start);
822 tend = (end == 0) ? object->size : OFF_TO_IDX(end + PAGE_MASK);
823 clearobjflags = tstart == 0 && tend >= object->size;
826 curgeneration = object->generation;
828 for (p = vm_page_find_least(object, tstart); p != NULL; p = np) {
832 np = TAILQ_NEXT(p, listq);
835 if (vm_page_sleep_if_busy(p, TRUE, "vpcwai")) {
836 if (object->generation != curgeneration)
838 np = vm_page_find_least(object, pi);
841 if (!vm_object_page_remove_write(p, flags, &clearobjflags))
844 n = vm_object_page_collect_flush(object, p, pagerflags,
845 flags, &clearobjflags);
846 if (object->generation != curgeneration)
848 np = vm_page_find_least(object, pi + n);
851 VOP_FSYNC(vp, (pagerflags & VM_PAGER_PUT_SYNC) ? MNT_WAIT : 0);
855 vm_object_clear_flag(object, OBJ_MIGHTBEDIRTY);
859 vm_object_page_collect_flush(vm_object_t object, vm_page_t p, int pagerflags,
860 int flags, int *clearobjflags)
862 vm_page_t ma[vm_pageout_page_count], p_first, tp;
863 int count, i, mreq, runlen;
865 mtx_assert(&vm_page_queue_mtx, MA_NOTOWNED);
866 vm_page_lock_assert(p, MA_NOTOWNED);
867 VM_OBJECT_LOCK_ASSERT(object, MA_OWNED);
872 for (tp = p; count < vm_pageout_page_count; count++) {
873 tp = vm_page_next(tp);
874 if (tp == NULL || tp->busy != 0 || (tp->oflags & VPO_BUSY) != 0)
876 if (!vm_object_page_remove_write(tp, flags, clearobjflags))
880 for (p_first = p; count < vm_pageout_page_count; count++) {
881 tp = vm_page_prev(p_first);
882 if (tp == NULL || tp->busy != 0 || (tp->oflags & VPO_BUSY) != 0)
884 if (!vm_object_page_remove_write(tp, flags, clearobjflags))
890 for (tp = p_first, i = 0; i < count; tp = TAILQ_NEXT(tp, listq), i++)
893 vm_pageout_flush(ma, count, pagerflags, mreq, &runlen);
898 * Note that there is absolutely no sense in writing out
899 * anonymous objects, so we track down the vnode object
901 * We invalidate (remove) all pages from the address space
902 * for semantic correctness.
904 * Note: certain anonymous maps, such as MAP_NOSYNC maps,
905 * may start out with a NULL object.
908 vm_object_sync(vm_object_t object, vm_ooffset_t offset, vm_size_t size,
909 boolean_t syncio, boolean_t invalidate)
911 vm_object_t backing_object;
918 VM_OBJECT_LOCK(object);
919 while ((backing_object = object->backing_object) != NULL) {
920 VM_OBJECT_LOCK(backing_object);
921 offset += object->backing_object_offset;
922 VM_OBJECT_UNLOCK(object);
923 object = backing_object;
924 if (object->size < OFF_TO_IDX(offset + size))
925 size = IDX_TO_OFF(object->size) - offset;
928 * Flush pages if writing is allowed, invalidate them
929 * if invalidation requested. Pages undergoing I/O
930 * will be ignored by vm_object_page_remove().
932 * We cannot lock the vnode and then wait for paging
933 * to complete without deadlocking against vm_fault.
934 * Instead we simply call vm_object_page_remove() and
935 * allow it to block internally on a page-by-page
936 * basis when it encounters pages undergoing async
939 if (object->type == OBJT_VNODE &&
940 (object->flags & OBJ_MIGHTBEDIRTY) != 0) {
943 VM_OBJECT_UNLOCK(object);
944 (void) vn_start_write(vp, &mp, V_WAIT);
945 vfslocked = VFS_LOCK_GIANT(vp->v_mount);
946 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
947 flags = (syncio || invalidate) ? OBJPC_SYNC : 0;
948 flags |= invalidate ? OBJPC_INVAL : 0;
949 VM_OBJECT_LOCK(object);
950 vm_object_page_clean(object, offset, offset + size, flags);
951 VM_OBJECT_UNLOCK(object);
953 VFS_UNLOCK_GIANT(vfslocked);
954 vn_finished_write(mp);
955 VM_OBJECT_LOCK(object);
957 if ((object->type == OBJT_VNODE ||
958 object->type == OBJT_DEVICE) && invalidate) {
960 purge = old_msync || (object->type == OBJT_DEVICE);
961 vm_object_page_remove(object,
963 OFF_TO_IDX(offset + size + PAGE_MASK),
964 purge ? FALSE : TRUE);
966 VM_OBJECT_UNLOCK(object);
972 * Implements the madvise function at the object/page level.
974 * MADV_WILLNEED (any object)
976 * Activate the specified pages if they are resident.
978 * MADV_DONTNEED (any object)
980 * Deactivate the specified pages if they are resident.
982 * MADV_FREE (OBJT_DEFAULT/OBJT_SWAP objects,
983 * OBJ_ONEMAPPING only)
985 * Deactivate and clean the specified pages if they are
986 * resident. This permits the process to reuse the pages
987 * without faulting or the kernel to reclaim the pages
991 vm_object_madvise(vm_object_t object, vm_pindex_t pindex, int count, int advise)
993 vm_pindex_t end, tpindex;
994 vm_object_t backing_object, tobject;
999 VM_OBJECT_LOCK(object);
1000 end = pindex + count;
1002 * Locate and adjust resident pages
1004 for (; pindex < end; pindex += 1) {
1010 * MADV_FREE only operates on OBJT_DEFAULT or OBJT_SWAP pages
1011 * and those pages must be OBJ_ONEMAPPING.
1013 if (advise == MADV_FREE) {
1014 if ((tobject->type != OBJT_DEFAULT &&
1015 tobject->type != OBJT_SWAP) ||
1016 (tobject->flags & OBJ_ONEMAPPING) == 0) {
1017 goto unlock_tobject;
1019 } else if (tobject->type == OBJT_PHYS)
1020 goto unlock_tobject;
1021 m = vm_page_lookup(tobject, tpindex);
1022 if (m == NULL && advise == MADV_WILLNEED) {
1024 * If the page is cached, reactivate it.
1026 m = vm_page_alloc(tobject, tpindex, VM_ALLOC_IFCACHED |
1031 * There may be swap even if there is no backing page
1033 if (advise == MADV_FREE && tobject->type == OBJT_SWAP)
1034 swap_pager_freespace(tobject, tpindex, 1);
1038 backing_object = tobject->backing_object;
1039 if (backing_object == NULL)
1040 goto unlock_tobject;
1041 VM_OBJECT_LOCK(backing_object);
1042 tpindex += OFF_TO_IDX(tobject->backing_object_offset);
1043 if (tobject != object)
1044 VM_OBJECT_UNLOCK(tobject);
1045 tobject = backing_object;
1047 } else if (m->valid != VM_PAGE_BITS_ALL)
1048 goto unlock_tobject;
1050 * If the page is not in a normal state, skip it.
1053 if (m->hold_count != 0 || m->wire_count != 0) {
1055 goto unlock_tobject;
1057 KASSERT((m->flags & (PG_FICTITIOUS | PG_UNMANAGED)) == 0,
1058 ("vm_object_madvise: page %p is not managed", m));
1059 if ((m->oflags & VPO_BUSY) || m->busy) {
1060 if (advise == MADV_WILLNEED) {
1062 * Reference the page before unlocking and
1063 * sleeping so that the page daemon is less
1064 * likely to reclaim it.
1066 vm_page_lock_queues();
1067 vm_page_flag_set(m, PG_REFERENCED);
1068 vm_page_unlock_queues();
1071 if (object != tobject)
1072 VM_OBJECT_UNLOCK(object);
1073 m->oflags |= VPO_WANTED;
1074 msleep(m, VM_OBJECT_MTX(tobject), PDROP | PVM, "madvpo",
1076 VM_OBJECT_LOCK(object);
1079 if (advise == MADV_WILLNEED) {
1080 vm_page_activate(m);
1081 } else if (advise == MADV_DONTNEED) {
1082 vm_page_dontneed(m);
1083 } else if (advise == MADV_FREE) {
1085 * Mark the page clean. This will allow the page
1086 * to be freed up by the system. However, such pages
1087 * are often reused quickly by malloc()/free()
1088 * so we do not do anything that would cause
1089 * a page fault if we can help it.
1091 * Specifically, we do not try to actually free
1092 * the page now nor do we try to put it in the
1093 * cache (which would cause a page fault on reuse).
1095 * But we do make the page is freeable as we
1096 * can without actually taking the step of unmapping
1099 pmap_clear_modify(m);
1102 vm_page_dontneed(m);
1105 if (advise == MADV_FREE && tobject->type == OBJT_SWAP)
1106 swap_pager_freespace(tobject, tpindex, 1);
1108 if (tobject != object)
1109 VM_OBJECT_UNLOCK(tobject);
1111 VM_OBJECT_UNLOCK(object);
1117 * Create a new object which is backed by the
1118 * specified existing object range. The source
1119 * object reference is deallocated.
1121 * The new object and offset into that object
1122 * are returned in the source parameters.
1126 vm_object_t *object, /* IN/OUT */
1127 vm_ooffset_t *offset, /* IN/OUT */
1136 * Don't create the new object if the old object isn't shared.
1138 if (source != NULL) {
1139 VM_OBJECT_LOCK(source);
1140 if (source->ref_count == 1 &&
1141 source->handle == NULL &&
1142 (source->type == OBJT_DEFAULT ||
1143 source->type == OBJT_SWAP)) {
1144 VM_OBJECT_UNLOCK(source);
1147 VM_OBJECT_UNLOCK(source);
1151 * Allocate a new object with the given length.
1153 result = vm_object_allocate(OBJT_DEFAULT, atop(length));
1156 * The new object shadows the source object, adding a reference to it.
1157 * Our caller changes his reference to point to the new object,
1158 * removing a reference to the source object. Net result: no change
1159 * of reference count.
1161 * Try to optimize the result object's page color when shadowing
1162 * in order to maintain page coloring consistency in the combined
1165 result->backing_object = source;
1167 * Store the offset into the source object, and fix up the offset into
1170 result->backing_object_offset = *offset;
1171 if (source != NULL) {
1172 VM_OBJECT_LOCK(source);
1173 LIST_INSERT_HEAD(&source->shadow_head, result, shadow_list);
1174 source->shadow_count++;
1175 #if VM_NRESERVLEVEL > 0
1176 result->flags |= source->flags & OBJ_COLORED;
1177 result->pg_color = (source->pg_color + OFF_TO_IDX(*offset)) &
1178 ((1 << (VM_NFREEORDER - 1)) - 1);
1180 VM_OBJECT_UNLOCK(source);
1185 * Return the new things
1194 * Split the pages in a map entry into a new object. This affords
1195 * easier removal of unused pages, and keeps object inheritance from
1196 * being a negative impact on memory usage.
1199 vm_object_split(vm_map_entry_t entry)
1201 vm_page_t m, m_next;
1202 vm_object_t orig_object, new_object, source;
1203 vm_pindex_t idx, offidxstart;
1206 orig_object = entry->object.vm_object;
1207 if (orig_object->type != OBJT_DEFAULT && orig_object->type != OBJT_SWAP)
1209 if (orig_object->ref_count <= 1)
1211 VM_OBJECT_UNLOCK(orig_object);
1213 offidxstart = OFF_TO_IDX(entry->offset);
1214 size = atop(entry->end - entry->start);
1217 * If swap_pager_copy() is later called, it will convert new_object
1218 * into a swap object.
1220 new_object = vm_object_allocate(OBJT_DEFAULT, size);
1223 * At this point, the new object is still private, so the order in
1224 * which the original and new objects are locked does not matter.
1226 VM_OBJECT_LOCK(new_object);
1227 VM_OBJECT_LOCK(orig_object);
1228 source = orig_object->backing_object;
1229 if (source != NULL) {
1230 VM_OBJECT_LOCK(source);
1231 if ((source->flags & OBJ_DEAD) != 0) {
1232 VM_OBJECT_UNLOCK(source);
1233 VM_OBJECT_UNLOCK(orig_object);
1234 VM_OBJECT_UNLOCK(new_object);
1235 vm_object_deallocate(new_object);
1236 VM_OBJECT_LOCK(orig_object);
1239 LIST_INSERT_HEAD(&source->shadow_head,
1240 new_object, shadow_list);
1241 source->shadow_count++;
1242 vm_object_reference_locked(source); /* for new_object */
1243 vm_object_clear_flag(source, OBJ_ONEMAPPING);
1244 VM_OBJECT_UNLOCK(source);
1245 new_object->backing_object_offset =
1246 orig_object->backing_object_offset + entry->offset;
1247 new_object->backing_object = source;
1249 if (orig_object->cred != NULL) {
1250 new_object->cred = orig_object->cred;
1251 crhold(orig_object->cred);
1252 new_object->charge = ptoa(size);
1253 KASSERT(orig_object->charge >= ptoa(size),
1254 ("orig_object->charge < 0"));
1255 orig_object->charge -= ptoa(size);
1258 m = vm_page_find_least(orig_object, offidxstart);
1259 for (; m != NULL && (idx = m->pindex - offidxstart) < size;
1261 m_next = TAILQ_NEXT(m, listq);
1264 * We must wait for pending I/O to complete before we can
1267 * We do not have to VM_PROT_NONE the page as mappings should
1268 * not be changed by this operation.
1270 if ((m->oflags & VPO_BUSY) || m->busy) {
1271 VM_OBJECT_UNLOCK(new_object);
1272 m->oflags |= VPO_WANTED;
1273 msleep(m, VM_OBJECT_MTX(orig_object), PVM, "spltwt", 0);
1274 VM_OBJECT_LOCK(new_object);
1278 vm_page_rename(m, new_object, idx);
1280 /* page automatically made dirty by rename and cache handled */
1283 if (orig_object->type == OBJT_SWAP) {
1285 * swap_pager_copy() can sleep, in which case the orig_object's
1286 * and new_object's locks are released and reacquired.
1288 swap_pager_copy(orig_object, new_object, offidxstart, 0);
1291 * Transfer any cached pages from orig_object to new_object.
1293 if (__predict_false(orig_object->cache != NULL))
1294 vm_page_cache_transfer(orig_object, offidxstart,
1297 VM_OBJECT_UNLOCK(orig_object);
1298 TAILQ_FOREACH(m, &new_object->memq, listq)
1300 VM_OBJECT_UNLOCK(new_object);
1301 entry->object.vm_object = new_object;
1302 entry->offset = 0LL;
1303 vm_object_deallocate(orig_object);
1304 VM_OBJECT_LOCK(new_object);
1307 #define OBSC_TEST_ALL_SHADOWED 0x0001
1308 #define OBSC_COLLAPSE_NOWAIT 0x0002
1309 #define OBSC_COLLAPSE_WAIT 0x0004
1312 vm_object_backing_scan(vm_object_t object, int op)
1316 vm_object_t backing_object;
1317 vm_pindex_t backing_offset_index;
1319 VM_OBJECT_LOCK_ASSERT(object, MA_OWNED);
1320 VM_OBJECT_LOCK_ASSERT(object->backing_object, MA_OWNED);
1322 backing_object = object->backing_object;
1323 backing_offset_index = OFF_TO_IDX(object->backing_object_offset);
1326 * Initial conditions
1328 if (op & OBSC_TEST_ALL_SHADOWED) {
1330 * We do not want to have to test for the existence of cache
1331 * or swap pages in the backing object. XXX but with the
1332 * new swapper this would be pretty easy to do.
1334 * XXX what about anonymous MAP_SHARED memory that hasn't
1335 * been ZFOD faulted yet? If we do not test for this, the
1336 * shadow test may succeed! XXX
1338 if (backing_object->type != OBJT_DEFAULT) {
1342 if (op & OBSC_COLLAPSE_WAIT) {
1343 vm_object_set_flag(backing_object, OBJ_DEAD);
1349 p = TAILQ_FIRST(&backing_object->memq);
1351 vm_page_t next = TAILQ_NEXT(p, listq);
1352 vm_pindex_t new_pindex = p->pindex - backing_offset_index;
1354 if (op & OBSC_TEST_ALL_SHADOWED) {
1358 * Ignore pages outside the parent object's range
1359 * and outside the parent object's mapping of the
1362 * note that we do not busy the backing object's
1366 p->pindex < backing_offset_index ||
1367 new_pindex >= object->size
1374 * See if the parent has the page or if the parent's
1375 * object pager has the page. If the parent has the
1376 * page but the page is not valid, the parent's
1377 * object pager must have the page.
1379 * If this fails, the parent does not completely shadow
1380 * the object and we might as well give up now.
1383 pp = vm_page_lookup(object, new_pindex);
1385 (pp == NULL || pp->valid == 0) &&
1386 !vm_pager_has_page(object, new_pindex, NULL, NULL)
1394 * Check for busy page
1396 if (op & (OBSC_COLLAPSE_WAIT | OBSC_COLLAPSE_NOWAIT)) {
1399 if (op & OBSC_COLLAPSE_NOWAIT) {
1400 if ((p->oflags & VPO_BUSY) ||
1406 } else if (op & OBSC_COLLAPSE_WAIT) {
1407 if ((p->oflags & VPO_BUSY) || p->busy) {
1408 VM_OBJECT_UNLOCK(object);
1409 p->oflags |= VPO_WANTED;
1410 msleep(p, VM_OBJECT_MTX(backing_object),
1411 PDROP | PVM, "vmocol", 0);
1412 VM_OBJECT_LOCK(object);
1413 VM_OBJECT_LOCK(backing_object);
1415 * If we slept, anything could have
1416 * happened. Since the object is
1417 * marked dead, the backing offset
1418 * should not have changed so we
1419 * just restart our scan.
1421 p = TAILQ_FIRST(&backing_object->memq);
1427 p->object == backing_object,
1428 ("vm_object_backing_scan: object mismatch")
1432 * Destroy any associated swap
1434 if (backing_object->type == OBJT_SWAP) {
1435 swap_pager_freespace(
1443 p->pindex < backing_offset_index ||
1444 new_pindex >= object->size
1447 * Page is out of the parent object's range, we
1448 * can simply destroy it.
1451 KASSERT(!pmap_page_is_mapped(p),
1452 ("freeing mapped page %p", p));
1453 if (p->wire_count == 0)
1462 pp = vm_page_lookup(object, new_pindex);
1465 vm_pager_has_page(object, new_pindex, NULL, NULL)
1468 * page already exists in parent OR swap exists
1469 * for this location in the parent. Destroy
1470 * the original page from the backing object.
1472 * Leave the parent's page alone
1475 KASSERT(!pmap_page_is_mapped(p),
1476 ("freeing mapped page %p", p));
1477 if (p->wire_count == 0)
1486 #if VM_NRESERVLEVEL > 0
1488 * Rename the reservation.
1490 vm_reserv_rename(p, object, backing_object,
1491 backing_offset_index);
1495 * Page does not exist in parent, rename the
1496 * page from the backing object to the main object.
1498 * If the page was mapped to a process, it can remain
1499 * mapped through the rename.
1502 vm_page_rename(p, object, new_pindex);
1504 /* page automatically made dirty by rename */
1513 * this version of collapse allows the operation to occur earlier and
1514 * when paging_in_progress is true for an object... This is not a complete
1515 * operation, but should plug 99.9% of the rest of the leaks.
1518 vm_object_qcollapse(vm_object_t object)
1520 vm_object_t backing_object = object->backing_object;
1522 VM_OBJECT_LOCK_ASSERT(object, MA_OWNED);
1523 VM_OBJECT_LOCK_ASSERT(backing_object, MA_OWNED);
1525 if (backing_object->ref_count != 1)
1528 vm_object_backing_scan(object, OBSC_COLLAPSE_NOWAIT);
1532 * vm_object_collapse:
1534 * Collapse an object with the object backing it.
1535 * Pages in the backing object are moved into the
1536 * parent, and the backing object is deallocated.
1539 vm_object_collapse(vm_object_t object)
1541 VM_OBJECT_LOCK_ASSERT(object, MA_OWNED);
1544 vm_object_t backing_object;
1547 * Verify that the conditions are right for collapse:
1549 * The object exists and the backing object exists.
1551 if ((backing_object = object->backing_object) == NULL)
1555 * we check the backing object first, because it is most likely
1558 VM_OBJECT_LOCK(backing_object);
1559 if (backing_object->handle != NULL ||
1560 (backing_object->type != OBJT_DEFAULT &&
1561 backing_object->type != OBJT_SWAP) ||
1562 (backing_object->flags & OBJ_DEAD) ||
1563 object->handle != NULL ||
1564 (object->type != OBJT_DEFAULT &&
1565 object->type != OBJT_SWAP) ||
1566 (object->flags & OBJ_DEAD)) {
1567 VM_OBJECT_UNLOCK(backing_object);
1572 object->paging_in_progress != 0 ||
1573 backing_object->paging_in_progress != 0
1575 vm_object_qcollapse(object);
1576 VM_OBJECT_UNLOCK(backing_object);
1580 * We know that we can either collapse the backing object (if
1581 * the parent is the only reference to it) or (perhaps) have
1582 * the parent bypass the object if the parent happens to shadow
1583 * all the resident pages in the entire backing object.
1585 * This is ignoring pager-backed pages such as swap pages.
1586 * vm_object_backing_scan fails the shadowing test in this
1589 if (backing_object->ref_count == 1) {
1591 * If there is exactly one reference to the backing
1592 * object, we can collapse it into the parent.
1594 vm_object_backing_scan(object, OBSC_COLLAPSE_WAIT);
1596 #if VM_NRESERVLEVEL > 0
1598 * Break any reservations from backing_object.
1600 if (__predict_false(!LIST_EMPTY(&backing_object->rvq)))
1601 vm_reserv_break_all(backing_object);
1605 * Move the pager from backing_object to object.
1607 if (backing_object->type == OBJT_SWAP) {
1609 * swap_pager_copy() can sleep, in which case
1610 * the backing_object's and object's locks are
1611 * released and reacquired.
1616 OFF_TO_IDX(object->backing_object_offset), TRUE);
1619 * Free any cached pages from backing_object.
1621 if (__predict_false(backing_object->cache != NULL))
1622 vm_page_cache_free(backing_object, 0, 0);
1625 * Object now shadows whatever backing_object did.
1626 * Note that the reference to
1627 * backing_object->backing_object moves from within
1628 * backing_object to within object.
1630 LIST_REMOVE(object, shadow_list);
1631 backing_object->shadow_count--;
1632 if (backing_object->backing_object) {
1633 VM_OBJECT_LOCK(backing_object->backing_object);
1634 LIST_REMOVE(backing_object, shadow_list);
1636 &backing_object->backing_object->shadow_head,
1637 object, shadow_list);
1639 * The shadow_count has not changed.
1641 VM_OBJECT_UNLOCK(backing_object->backing_object);
1643 object->backing_object = backing_object->backing_object;
1644 object->backing_object_offset +=
1645 backing_object->backing_object_offset;
1648 * Discard backing_object.
1650 * Since the backing object has no pages, no pager left,
1651 * and no object references within it, all that is
1652 * necessary is to dispose of it.
1654 KASSERT(backing_object->ref_count == 1, (
1655 "backing_object %p was somehow re-referenced during collapse!",
1657 VM_OBJECT_UNLOCK(backing_object);
1658 vm_object_destroy(backing_object);
1662 vm_object_t new_backing_object;
1665 * If we do not entirely shadow the backing object,
1666 * there is nothing we can do so we give up.
1668 if (object->resident_page_count != object->size &&
1669 vm_object_backing_scan(object,
1670 OBSC_TEST_ALL_SHADOWED) == 0) {
1671 VM_OBJECT_UNLOCK(backing_object);
1676 * Make the parent shadow the next object in the
1677 * chain. Deallocating backing_object will not remove
1678 * it, since its reference count is at least 2.
1680 LIST_REMOVE(object, shadow_list);
1681 backing_object->shadow_count--;
1683 new_backing_object = backing_object->backing_object;
1684 if ((object->backing_object = new_backing_object) != NULL) {
1685 VM_OBJECT_LOCK(new_backing_object);
1687 &new_backing_object->shadow_head,
1691 new_backing_object->shadow_count++;
1692 vm_object_reference_locked(new_backing_object);
1693 VM_OBJECT_UNLOCK(new_backing_object);
1694 object->backing_object_offset +=
1695 backing_object->backing_object_offset;
1699 * Drop the reference count on backing_object. Since
1700 * its ref_count was at least 2, it will not vanish.
1702 backing_object->ref_count--;
1703 VM_OBJECT_UNLOCK(backing_object);
1708 * Try again with this object's new backing object.
1714 * vm_object_page_remove:
1716 * For the given object, either frees or invalidates each of the
1717 * specified pages. In general, a page is freed. However, if a
1718 * page is wired for any reason other than the existence of a
1719 * managed, wired mapping, then it may be invalidated but not
1720 * removed from the object. Pages are specified by the given
1721 * range ["start", "end") and Boolean "clean_only". As a
1722 * special case, if "end" is zero, then the range extends from
1723 * "start" to the end of the object. If "clean_only" is TRUE,
1724 * then only the non-dirty pages within the specified range are
1727 * In general, this operation should only be performed on objects
1728 * that contain managed pages. There are two exceptions. First,
1729 * it may be performed on the kernel and kmem objects. Second,
1730 * it may be used by msync(..., MS_INVALIDATE) to invalidate
1731 * device-backed pages. In both of these cases, "clean_only"
1734 * The object must be locked.
1737 vm_object_page_remove(vm_object_t object, vm_pindex_t start, vm_pindex_t end,
1738 boolean_t clean_only)
1743 VM_OBJECT_LOCK_ASSERT(object, MA_OWNED);
1744 if (object->resident_page_count == 0)
1748 * Since physically-backed objects do not use managed pages, we can't
1749 * remove pages from the object (we must instead remove the page
1750 * references, and then destroy the object).
1752 KASSERT(object->type != OBJT_PHYS || object == kernel_object ||
1753 object == kmem_object,
1754 ("attempt to remove pages from a physical object"));
1756 vm_object_pip_add(object, 1);
1758 p = vm_page_find_least(object, start);
1761 * Assert: the variable p is either (1) the page with the
1762 * least pindex greater than or equal to the parameter pindex
1766 p != NULL && (p->pindex < end || end == 0);
1768 next = TAILQ_NEXT(p, listq);
1771 * If the page is wired for any reason besides the
1772 * existence of managed, wired mappings, then it cannot
1773 * be freed. For example, fictitious pages, which
1774 * represent device memory, are inherently wired and
1775 * cannot be freed. They can, however, be invalidated
1776 * if "clean_only" is FALSE.
1779 if ((wirings = p->wire_count) != 0 &&
1780 (wirings = pmap_page_wired_mappings(p)) != p->wire_count) {
1781 /* Fictitious pages do not have managed mappings. */
1782 if ((p->flags & PG_FICTITIOUS) == 0)
1784 /* Account for removal of managed, wired mappings. */
1785 p->wire_count -= wirings;
1793 if (vm_page_sleep_if_busy(p, TRUE, "vmopar"))
1795 KASSERT((p->flags & PG_FICTITIOUS) == 0,
1796 ("vm_object_page_remove: page %p is fictitious", p));
1797 if (clean_only && p->valid) {
1798 pmap_remove_write(p);
1805 /* Account for removal of managed, wired mappings. */
1807 p->wire_count -= wirings;
1811 vm_object_pip_wakeup(object);
1813 if (__predict_false(object->cache != NULL))
1814 vm_page_cache_free(object, start, end);
1818 * Populate the specified range of the object with valid pages. Returns
1819 * TRUE if the range is successfully populated and FALSE otherwise.
1821 * Note: This function should be optimized to pass a larger array of
1822 * pages to vm_pager_get_pages() before it is applied to a non-
1823 * OBJT_DEVICE object.
1825 * The object must be locked.
1828 vm_object_populate(vm_object_t object, vm_pindex_t start, vm_pindex_t end)
1834 VM_OBJECT_LOCK_ASSERT(object, MA_OWNED);
1835 for (pindex = start; pindex < end; pindex++) {
1836 m = vm_page_grab(object, pindex, VM_ALLOC_NORMAL |
1838 if (m->valid != VM_PAGE_BITS_ALL) {
1840 rv = vm_pager_get_pages(object, ma, 1, 0);
1841 m = vm_page_lookup(object, pindex);
1844 if (rv != VM_PAGER_OK) {
1852 * Keep "m" busy because a subsequent iteration may unlock
1856 if (pindex > start) {
1857 m = vm_page_lookup(object, start);
1858 while (m != NULL && m->pindex < pindex) {
1860 m = TAILQ_NEXT(m, listq);
1863 return (pindex == end);
1867 * Routine: vm_object_coalesce
1868 * Function: Coalesces two objects backing up adjoining
1869 * regions of memory into a single object.
1871 * returns TRUE if objects were combined.
1873 * NOTE: Only works at the moment if the second object is NULL -
1874 * if it's not, which object do we lock first?
1877 * prev_object First object to coalesce
1878 * prev_offset Offset into prev_object
1879 * prev_size Size of reference to prev_object
1880 * next_size Size of reference to the second object
1881 * reserved Indicator that extension region has
1882 * swap accounted for
1885 * The object must *not* be locked.
1888 vm_object_coalesce(vm_object_t prev_object, vm_ooffset_t prev_offset,
1889 vm_size_t prev_size, vm_size_t next_size, boolean_t reserved)
1891 vm_pindex_t next_pindex;
1893 if (prev_object == NULL)
1895 VM_OBJECT_LOCK(prev_object);
1896 if (prev_object->type != OBJT_DEFAULT &&
1897 prev_object->type != OBJT_SWAP) {
1898 VM_OBJECT_UNLOCK(prev_object);
1903 * Try to collapse the object first
1905 vm_object_collapse(prev_object);
1908 * Can't coalesce if: . more than one reference . paged out . shadows
1909 * another object . has a copy elsewhere (any of which mean that the
1910 * pages not mapped to prev_entry may be in use anyway)
1912 if (prev_object->backing_object != NULL) {
1913 VM_OBJECT_UNLOCK(prev_object);
1917 prev_size >>= PAGE_SHIFT;
1918 next_size >>= PAGE_SHIFT;
1919 next_pindex = OFF_TO_IDX(prev_offset) + prev_size;
1921 if ((prev_object->ref_count > 1) &&
1922 (prev_object->size != next_pindex)) {
1923 VM_OBJECT_UNLOCK(prev_object);
1928 * Account for the charge.
1930 if (prev_object->cred != NULL) {
1933 * If prev_object was charged, then this mapping,
1934 * althought not charged now, may become writable
1935 * later. Non-NULL cred in the object would prevent
1936 * swap reservation during enabling of the write
1937 * access, so reserve swap now. Failed reservation
1938 * cause allocation of the separate object for the map
1939 * entry, and swap reservation for this entry is
1940 * managed in appropriate time.
1942 if (!reserved && !swap_reserve_by_cred(ptoa(next_size),
1943 prev_object->cred)) {
1946 prev_object->charge += ptoa(next_size);
1950 * Remove any pages that may still be in the object from a previous
1953 if (next_pindex < prev_object->size) {
1954 vm_object_page_remove(prev_object,
1956 next_pindex + next_size, FALSE);
1957 if (prev_object->type == OBJT_SWAP)
1958 swap_pager_freespace(prev_object,
1959 next_pindex, next_size);
1961 if (prev_object->cred != NULL) {
1962 KASSERT(prev_object->charge >=
1963 ptoa(prev_object->size - next_pindex),
1964 ("object %p overcharged 1 %jx %jx", prev_object,
1965 (uintmax_t)next_pindex, (uintmax_t)next_size));
1966 prev_object->charge -= ptoa(prev_object->size -
1973 * Extend the object if necessary.
1975 if (next_pindex + next_size > prev_object->size)
1976 prev_object->size = next_pindex + next_size;
1978 VM_OBJECT_UNLOCK(prev_object);
1983 vm_object_set_writeable_dirty(vm_object_t object)
1986 VM_OBJECT_LOCK_ASSERT(object, MA_OWNED);
1987 if (object->type != OBJT_VNODE)
1989 object->generation++;
1990 if ((object->flags & OBJ_MIGHTBEDIRTY) != 0)
1992 vm_object_set_flag(object, OBJ_MIGHTBEDIRTY);
1995 #include "opt_ddb.h"
1997 #include <sys/kernel.h>
1999 #include <sys/cons.h>
2001 #include <ddb/ddb.h>
2004 _vm_object_in_map(vm_map_t map, vm_object_t object, vm_map_entry_t entry)
2007 vm_map_entry_t tmpe;
2015 tmpe = map->header.next;
2016 entcount = map->nentries;
2017 while (entcount-- && (tmpe != &map->header)) {
2018 if (_vm_object_in_map(map, object, tmpe)) {
2023 } else if (entry->eflags & MAP_ENTRY_IS_SUB_MAP) {
2024 tmpm = entry->object.sub_map;
2025 tmpe = tmpm->header.next;
2026 entcount = tmpm->nentries;
2027 while (entcount-- && tmpe != &tmpm->header) {
2028 if (_vm_object_in_map(tmpm, object, tmpe)) {
2033 } else if ((obj = entry->object.vm_object) != NULL) {
2034 for (; obj; obj = obj->backing_object)
2035 if (obj == object) {
2043 vm_object_in_map(vm_object_t object)
2047 /* sx_slock(&allproc_lock); */
2048 FOREACH_PROC_IN_SYSTEM(p) {
2049 if (!p->p_vmspace /* || (p->p_flag & (P_SYSTEM|P_WEXIT)) */)
2051 if (_vm_object_in_map(&p->p_vmspace->vm_map, object, 0)) {
2052 /* sx_sunlock(&allproc_lock); */
2056 /* sx_sunlock(&allproc_lock); */
2057 if (_vm_object_in_map(kernel_map, object, 0))
2059 if (_vm_object_in_map(kmem_map, object, 0))
2061 if (_vm_object_in_map(pager_map, object, 0))
2063 if (_vm_object_in_map(buffer_map, object, 0))
2068 DB_SHOW_COMMAND(vmochk, vm_object_check)
2073 * make sure that internal objs are in a map somewhere
2074 * and none have zero ref counts.
2076 TAILQ_FOREACH(object, &vm_object_list, object_list) {
2077 if (object->handle == NULL &&
2078 (object->type == OBJT_DEFAULT || object->type == OBJT_SWAP)) {
2079 if (object->ref_count == 0) {
2080 db_printf("vmochk: internal obj has zero ref count: %ld\n",
2081 (long)object->size);
2083 if (!vm_object_in_map(object)) {
2085 "vmochk: internal obj is not in a map: "
2086 "ref: %d, size: %lu: 0x%lx, backing_object: %p\n",
2087 object->ref_count, (u_long)object->size,
2088 (u_long)object->size,
2089 (void *)object->backing_object);
2096 * vm_object_print: [ debug ]
2098 DB_SHOW_COMMAND(object, vm_object_print_static)
2100 /* XXX convert args. */
2101 vm_object_t object = (vm_object_t)addr;
2102 boolean_t full = have_addr;
2106 /* XXX count is an (unused) arg. Avoid shadowing it. */
2107 #define count was_count
2115 "Object %p: type=%d, size=0x%jx, res=%d, ref=%d, flags=0x%x ruid %d charge %jx\n",
2116 object, (int)object->type, (uintmax_t)object->size,
2117 object->resident_page_count, object->ref_count, object->flags,
2118 object->cred ? object->cred->cr_ruid : -1, (uintmax_t)object->charge);
2119 db_iprintf(" sref=%d, backing_object(%d)=(%p)+0x%jx\n",
2120 object->shadow_count,
2121 object->backing_object ? object->backing_object->ref_count : 0,
2122 object->backing_object, (uintmax_t)object->backing_object_offset);
2129 TAILQ_FOREACH(p, &object->memq, listq) {
2131 db_iprintf("memory:=");
2132 else if (count == 6) {
2140 db_printf("(off=0x%jx,page=0x%jx)",
2141 (uintmax_t)p->pindex, (uintmax_t)VM_PAGE_TO_PHYS(p));
2151 /* XXX need this non-static entry for calling from vm_map_print. */
2154 /* db_expr_t */ long addr,
2155 boolean_t have_addr,
2156 /* db_expr_t */ long count,
2159 vm_object_print_static(addr, have_addr, count, modif);
2162 DB_SHOW_COMMAND(vmopag, vm_object_print_pages)
2167 vm_page_t m, prev_m;
2171 TAILQ_FOREACH(object, &vm_object_list, object_list) {
2172 db_printf("new object: %p\n", (void *)object);
2183 TAILQ_FOREACH(m, &object->memq, listq) {
2184 if (m->pindex > 128)
2186 if ((prev_m = TAILQ_PREV(m, pglist, listq)) != NULL &&
2187 prev_m->pindex + 1 != m->pindex) {
2189 db_printf(" index(%ld)run(%d)pa(0x%lx)\n",
2190 (long)fidx, rcount, (long)pa);
2202 (VM_PAGE_TO_PHYS(m) == pa + rcount * PAGE_SIZE)) {
2207 db_printf(" index(%ld)run(%d)pa(0x%lx)\n",
2208 (long)fidx, rcount, (long)pa);
2218 pa = VM_PAGE_TO_PHYS(m);
2222 db_printf(" index(%ld)run(%d)pa(0x%lx)\n",
2223 (long)fidx, rcount, (long)pa);