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/rwlock.h>
82 #include <sys/vnode.h>
83 #include <sys/vmmeter.h>
87 #include <vm/vm_param.h>
89 #include <vm/vm_map.h>
90 #include <vm/vm_object.h>
91 #include <vm/vm_page.h>
92 #include <vm/vm_pageout.h>
93 #include <vm/vm_pager.h>
94 #include <vm/swap_pager.h>
95 #include <vm/vm_kern.h>
96 #include <vm/vm_extern.h>
97 #include <vm/vm_radix.h>
98 #include <vm/vm_reserv.h>
101 static int old_msync;
102 SYSCTL_INT(_vm, OID_AUTO, old_msync, CTLFLAG_RW, &old_msync, 0,
103 "Use old (insecure) msync behavior");
105 static int vm_object_page_collect_flush(vm_object_t object, vm_page_t p,
106 int pagerflags, int flags, boolean_t *clearobjflags,
108 static boolean_t vm_object_page_remove_write(vm_page_t p, int flags,
109 boolean_t *clearobjflags);
110 static void vm_object_qcollapse(vm_object_t object);
111 static void vm_object_vndeallocate(vm_object_t object);
114 * Virtual memory objects maintain the actual data
115 * associated with allocated virtual memory. A given
116 * page of memory exists within exactly one object.
118 * An object is only deallocated when all "references"
119 * are given up. Only one "reference" to a given
120 * region of an object should be writeable.
122 * Associated with each object is a list of all resident
123 * memory pages belonging to that object; this list is
124 * maintained by the "vm_page" module, and locked by the object's
127 * Each object also records a "pager" routine which is
128 * used to retrieve (and store) pages to the proper backing
129 * storage. In addition, objects may be backed by other
130 * objects from which they were virtual-copied.
132 * The only items within the object structure which are
133 * modified after time of creation are:
134 * reference count locked by object's lock
135 * pager routine locked by object's lock
139 struct object_q vm_object_list;
140 struct mtx vm_object_list_mtx; /* lock for object list and count */
142 struct vm_object kernel_object_store;
143 struct vm_object kmem_object_store;
145 static SYSCTL_NODE(_vm_stats, OID_AUTO, object, CTLFLAG_RD, 0,
148 static long object_collapses;
149 SYSCTL_LONG(_vm_stats_object, OID_AUTO, collapses, CTLFLAG_RD,
150 &object_collapses, 0, "VM object collapses");
152 static long object_bypasses;
153 SYSCTL_LONG(_vm_stats_object, OID_AUTO, bypasses, CTLFLAG_RD,
154 &object_bypasses, 0, "VM object bypasses");
156 static uma_zone_t obj_zone;
158 static int vm_object_zinit(void *mem, int size, int flags);
161 static void vm_object_zdtor(void *mem, int size, void *arg);
164 vm_object_zdtor(void *mem, int size, void *arg)
168 object = (vm_object_t)mem;
169 KASSERT(TAILQ_EMPTY(&object->memq),
170 ("object %p has resident pages in its memq", object));
171 KASSERT(vm_radix_is_empty(&object->rtree),
172 ("object %p has resident pages in its trie", object));
173 #if VM_NRESERVLEVEL > 0
174 KASSERT(LIST_EMPTY(&object->rvq),
175 ("object %p has reservations",
178 KASSERT(vm_object_cache_is_empty(object),
179 ("object %p has cached pages",
181 KASSERT(object->paging_in_progress == 0,
182 ("object %p paging_in_progress = %d",
183 object, object->paging_in_progress));
184 KASSERT(object->resident_page_count == 0,
185 ("object %p resident_page_count = %d",
186 object, object->resident_page_count));
187 KASSERT(object->shadow_count == 0,
188 ("object %p shadow_count = %d",
189 object, object->shadow_count));
194 vm_object_zinit(void *mem, int size, int flags)
198 object = (vm_object_t)mem;
199 bzero(&object->lock, sizeof(object->lock));
200 rw_init_flags(&object->lock, "vm object", RW_DUPOK);
202 /* These are true for any object that has been freed */
203 object->rtree.rt_root = 0;
204 object->paging_in_progress = 0;
205 object->resident_page_count = 0;
206 object->shadow_count = 0;
207 object->cache.rt_root = 0;
212 _vm_object_allocate(objtype_t type, vm_pindex_t size, vm_object_t object)
215 TAILQ_INIT(&object->memq);
216 LIST_INIT(&object->shadow_head);
221 panic("_vm_object_allocate: can't create OBJT_DEAD");
224 object->flags = OBJ_ONEMAPPING;
228 object->flags = OBJ_FICTITIOUS | OBJ_UNMANAGED;
231 object->flags = OBJ_FICTITIOUS;
234 object->flags = OBJ_UNMANAGED;
240 panic("_vm_object_allocate: type %d is undefined", type);
243 object->generation = 1;
244 object->ref_count = 1;
245 object->memattr = VM_MEMATTR_DEFAULT;
248 object->handle = NULL;
249 object->backing_object = NULL;
250 object->backing_object_offset = (vm_ooffset_t) 0;
251 #if VM_NRESERVLEVEL > 0
252 LIST_INIT(&object->rvq);
255 mtx_lock(&vm_object_list_mtx);
256 TAILQ_INSERT_TAIL(&vm_object_list, object, object_list);
257 mtx_unlock(&vm_object_list_mtx);
263 * Initialize the VM objects module.
268 TAILQ_INIT(&vm_object_list);
269 mtx_init(&vm_object_list_mtx, "vm object_list", NULL, MTX_DEF);
271 rw_init(&kernel_object->lock, "kernel vm object");
272 _vm_object_allocate(OBJT_PHYS, OFF_TO_IDX(VM_MAX_KERNEL_ADDRESS - VM_MIN_KERNEL_ADDRESS),
274 #if VM_NRESERVLEVEL > 0
275 kernel_object->flags |= OBJ_COLORED;
276 kernel_object->pg_color = (u_short)atop(VM_MIN_KERNEL_ADDRESS);
279 rw_init(&kmem_object->lock, "kmem vm object");
280 _vm_object_allocate(OBJT_PHYS, OFF_TO_IDX(VM_MAX_KERNEL_ADDRESS - VM_MIN_KERNEL_ADDRESS),
282 #if VM_NRESERVLEVEL > 0
283 kmem_object->flags |= OBJ_COLORED;
284 kmem_object->pg_color = (u_short)atop(VM_MIN_KERNEL_ADDRESS);
288 * The lock portion of struct vm_object must be type stable due
289 * to vm_pageout_fallback_object_lock locking a vm object
290 * without holding any references to it.
292 obj_zone = uma_zcreate("VM OBJECT", sizeof (struct vm_object), NULL,
298 vm_object_zinit, NULL, UMA_ALIGN_PTR, UMA_ZONE_NOFREE);
304 vm_object_clear_flag(vm_object_t object, u_short bits)
307 VM_OBJECT_ASSERT_WLOCKED(object);
308 object->flags &= ~bits;
312 * Sets the default memory attribute for the specified object. Pages
313 * that are allocated to this object are by default assigned this memory
316 * Presently, this function must be called before any pages are allocated
317 * to the object. In the future, this requirement may be relaxed for
318 * "default" and "swap" objects.
321 vm_object_set_memattr(vm_object_t object, vm_memattr_t memattr)
324 VM_OBJECT_ASSERT_WLOCKED(object);
325 switch (object->type) {
333 if (!TAILQ_EMPTY(&object->memq))
334 return (KERN_FAILURE);
337 return (KERN_INVALID_ARGUMENT);
339 panic("vm_object_set_memattr: object %p is of undefined type",
342 object->memattr = memattr;
343 return (KERN_SUCCESS);
347 vm_object_pip_add(vm_object_t object, short i)
350 VM_OBJECT_ASSERT_WLOCKED(object);
351 object->paging_in_progress += i;
355 vm_object_pip_subtract(vm_object_t object, short i)
358 VM_OBJECT_ASSERT_WLOCKED(object);
359 object->paging_in_progress -= i;
363 vm_object_pip_wakeup(vm_object_t object)
366 VM_OBJECT_ASSERT_WLOCKED(object);
367 object->paging_in_progress--;
368 if ((object->flags & OBJ_PIPWNT) && object->paging_in_progress == 0) {
369 vm_object_clear_flag(object, OBJ_PIPWNT);
375 vm_object_pip_wakeupn(vm_object_t object, short i)
378 VM_OBJECT_ASSERT_WLOCKED(object);
380 object->paging_in_progress -= i;
381 if ((object->flags & OBJ_PIPWNT) && object->paging_in_progress == 0) {
382 vm_object_clear_flag(object, OBJ_PIPWNT);
388 vm_object_pip_wait(vm_object_t object, char *waitid)
391 VM_OBJECT_ASSERT_WLOCKED(object);
392 while (object->paging_in_progress) {
393 object->flags |= OBJ_PIPWNT;
394 VM_OBJECT_SLEEP(object, object, PVM, waitid, 0);
399 * vm_object_allocate:
401 * Returns a new object with the given size.
404 vm_object_allocate(objtype_t type, vm_pindex_t size)
408 object = (vm_object_t)uma_zalloc(obj_zone, M_WAITOK);
409 _vm_object_allocate(type, size, object);
415 * vm_object_reference:
417 * Gets another reference to the given object. Note: OBJ_DEAD
418 * objects can be referenced during final cleaning.
421 vm_object_reference(vm_object_t object)
425 VM_OBJECT_WLOCK(object);
426 vm_object_reference_locked(object);
427 VM_OBJECT_WUNLOCK(object);
431 * vm_object_reference_locked:
433 * Gets another reference to the given object.
435 * The object must be locked.
438 vm_object_reference_locked(vm_object_t object)
442 VM_OBJECT_ASSERT_WLOCKED(object);
444 if (object->type == OBJT_VNODE) {
451 * Handle deallocating an object of type OBJT_VNODE.
454 vm_object_vndeallocate(vm_object_t object)
456 struct vnode *vp = (struct vnode *) object->handle;
458 VM_OBJECT_ASSERT_WLOCKED(object);
459 KASSERT(object->type == OBJT_VNODE,
460 ("vm_object_vndeallocate: not a vnode object"));
461 KASSERT(vp != NULL, ("vm_object_vndeallocate: missing vp"));
463 if (object->ref_count == 0) {
464 vprint("vm_object_vndeallocate", vp);
465 panic("vm_object_vndeallocate: bad object reference count");
469 if (object->ref_count > 1) {
471 VM_OBJECT_WUNLOCK(object);
472 /* vrele may need the vnode lock. */
476 VM_OBJECT_WUNLOCK(object);
477 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
479 VM_OBJECT_WLOCK(object);
481 if (object->type == OBJT_DEAD) {
482 VM_OBJECT_WUNLOCK(object);
485 if (object->ref_count == 0)
487 VM_OBJECT_WUNLOCK(object);
494 * vm_object_deallocate:
496 * Release a reference to the specified object,
497 * gained either through a vm_object_allocate
498 * or a vm_object_reference call. When all references
499 * are gone, storage associated with this object
500 * may be relinquished.
502 * No object may be locked.
505 vm_object_deallocate(vm_object_t object)
510 while (object != NULL) {
511 VM_OBJECT_WLOCK(object);
512 if (object->type == OBJT_VNODE) {
513 vm_object_vndeallocate(object);
517 KASSERT(object->ref_count != 0,
518 ("vm_object_deallocate: object deallocated too many times: %d", object->type));
521 * If the reference count goes to 0 we start calling
522 * vm_object_terminate() on the object chain.
523 * A ref count of 1 may be a special case depending on the
524 * shadow count being 0 or 1.
527 if (object->ref_count > 1) {
528 VM_OBJECT_WUNLOCK(object);
530 } else if (object->ref_count == 1) {
531 if (object->type == OBJT_SWAP &&
532 (object->flags & OBJ_TMPFS) != 0) {
533 vp = object->un_pager.swp.swp_tmpfs;
535 VM_OBJECT_WUNLOCK(object);
536 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
538 VM_OBJECT_WLOCK(object);
539 if (object->type == OBJT_DEAD ||
540 object->ref_count != 1) {
541 VM_OBJECT_WUNLOCK(object);
545 if ((object->flags & OBJ_TMPFS) != 0)
549 if (object->shadow_count == 0 &&
550 object->handle == NULL &&
551 (object->type == OBJT_DEFAULT ||
552 (object->type == OBJT_SWAP &&
553 (object->flags & OBJ_TMPFS) == 0))) {
554 vm_object_set_flag(object, OBJ_ONEMAPPING);
555 } else if ((object->shadow_count == 1) &&
556 (object->handle == NULL) &&
557 (object->type == OBJT_DEFAULT ||
558 object->type == OBJT_SWAP)) {
559 KASSERT((object->flags & OBJ_TMPFS) == 0,
560 ("shadowed tmpfs v_object %p", object));
563 robject = LIST_FIRST(&object->shadow_head);
564 KASSERT(robject != NULL,
565 ("vm_object_deallocate: ref_count: %d, shadow_count: %d",
567 object->shadow_count));
568 if (!VM_OBJECT_TRYWLOCK(robject)) {
570 * Avoid a potential deadlock.
573 VM_OBJECT_WUNLOCK(object);
575 * More likely than not the thread
576 * holding robject's lock has lower
577 * priority than the current thread.
578 * Let the lower priority thread run.
584 * Collapse object into its shadow unless its
585 * shadow is dead. In that case, object will
586 * be deallocated by the thread that is
587 * deallocating its shadow.
589 if ((robject->flags & OBJ_DEAD) == 0 &&
590 (robject->handle == NULL) &&
591 (robject->type == OBJT_DEFAULT ||
592 robject->type == OBJT_SWAP)) {
594 robject->ref_count++;
596 if (robject->paging_in_progress) {
597 VM_OBJECT_WUNLOCK(object);
598 vm_object_pip_wait(robject,
600 temp = robject->backing_object;
601 if (object == temp) {
602 VM_OBJECT_WLOCK(object);
605 } else if (object->paging_in_progress) {
606 VM_OBJECT_WUNLOCK(robject);
607 object->flags |= OBJ_PIPWNT;
608 VM_OBJECT_SLEEP(object, object,
609 PDROP | PVM, "objde2", 0);
610 VM_OBJECT_WLOCK(robject);
611 temp = robject->backing_object;
612 if (object == temp) {
613 VM_OBJECT_WLOCK(object);
617 VM_OBJECT_WUNLOCK(object);
619 if (robject->ref_count == 1) {
620 robject->ref_count--;
625 vm_object_collapse(object);
626 VM_OBJECT_WUNLOCK(object);
629 VM_OBJECT_WUNLOCK(robject);
631 VM_OBJECT_WUNLOCK(object);
635 temp = object->backing_object;
637 VM_OBJECT_WLOCK(temp);
638 LIST_REMOVE(object, shadow_list);
639 temp->shadow_count--;
640 VM_OBJECT_WUNLOCK(temp);
641 object->backing_object = NULL;
644 * Don't double-terminate, we could be in a termination
645 * recursion due to the terminate having to sync data
648 if ((object->flags & OBJ_DEAD) == 0)
649 vm_object_terminate(object);
651 VM_OBJECT_WUNLOCK(object);
657 * vm_object_destroy removes the object from the global object list
658 * and frees the space for the object.
661 vm_object_destroy(vm_object_t object)
665 * Remove the object from the global object list.
667 mtx_lock(&vm_object_list_mtx);
668 TAILQ_REMOVE(&vm_object_list, object, object_list);
669 mtx_unlock(&vm_object_list_mtx);
672 * Release the allocation charge.
674 if (object->cred != NULL) {
675 KASSERT(object->type == OBJT_DEFAULT ||
676 object->type == OBJT_SWAP,
677 ("vm_object_terminate: non-swap obj %p has cred",
679 swap_release_by_cred(object->charge, object->cred);
681 crfree(object->cred);
686 * Free the space for the object.
688 uma_zfree(obj_zone, object);
692 * vm_object_terminate actually destroys the specified object, freeing
693 * up all previously used resources.
695 * The object must be locked.
696 * This routine may block.
699 vm_object_terminate(vm_object_t object)
703 VM_OBJECT_ASSERT_WLOCKED(object);
706 * Make sure no one uses us.
708 vm_object_set_flag(object, OBJ_DEAD);
711 * wait for the pageout daemon to be done with the object
713 vm_object_pip_wait(object, "objtrm");
715 KASSERT(!object->paging_in_progress,
716 ("vm_object_terminate: pageout in progress"));
719 * Clean and free the pages, as appropriate. All references to the
720 * object are gone, so we don't need to lock it.
722 if (object->type == OBJT_VNODE) {
723 struct vnode *vp = (struct vnode *)object->handle;
726 * Clean pages and flush buffers.
728 vm_object_page_clean(object, 0, 0, OBJPC_SYNC);
729 VM_OBJECT_WUNLOCK(object);
731 vinvalbuf(vp, V_SAVE, 0, 0);
733 VM_OBJECT_WLOCK(object);
736 KASSERT(object->ref_count == 0,
737 ("vm_object_terminate: object with references, ref_count=%d",
741 * Free any remaining pageable pages. This also removes them from the
742 * paging queues. However, don't free wired pages, just remove them
743 * from the object. Rather than incrementally removing each page from
744 * the object, the page and object are reset to any empty state.
746 TAILQ_FOREACH_SAFE(p, &object->memq, listq, p_next) {
747 KASSERT(!p->busy && (p->oflags & VPO_BUSY) == 0,
748 ("vm_object_terminate: freeing busy page %p", p));
751 * Optimize the page's removal from the object by resetting
752 * its "object" field. Specifically, if the page is not
753 * wired, then the effect of this assignment is that
754 * vm_page_free()'s call to vm_page_remove() will return
755 * immediately without modifying the page or the object.
758 if (p->wire_count == 0) {
760 PCPU_INC(cnt.v_pfree);
765 * If the object contained any pages, then reset it to an empty state.
766 * None of the object's fields, including "resident_page_count", were
767 * modified by the preceding loop.
769 if (object->resident_page_count != 0) {
770 vm_radix_reclaim_allnodes(&object->rtree);
771 TAILQ_INIT(&object->memq);
772 object->resident_page_count = 0;
773 if (object->type == OBJT_VNODE)
774 vdrop(object->handle);
777 #if VM_NRESERVLEVEL > 0
778 if (__predict_false(!LIST_EMPTY(&object->rvq)))
779 vm_reserv_break_all(object);
781 if (__predict_false(!vm_object_cache_is_empty(object)))
782 vm_page_cache_free(object, 0, 0);
785 * Let the pager know object is dead.
787 vm_pager_deallocate(object);
788 VM_OBJECT_WUNLOCK(object);
790 vm_object_destroy(object);
794 * Make the page read-only so that we can clear the object flags. However, if
795 * this is a nosync mmap then the object is likely to stay dirty so do not
796 * mess with the page and do not clear the object flags. Returns TRUE if the
797 * page should be flushed, and FALSE otherwise.
800 vm_object_page_remove_write(vm_page_t p, int flags, boolean_t *clearobjflags)
804 * If we have been asked to skip nosync pages and this is a
805 * nosync page, skip it. Note that the object flags were not
806 * cleared in this case so we do not have to set them.
808 if ((flags & OBJPC_NOSYNC) != 0 && (p->oflags & VPO_NOSYNC) != 0) {
809 *clearobjflags = FALSE;
812 pmap_remove_write(p);
813 return (p->dirty != 0);
818 * vm_object_page_clean
820 * Clean all dirty pages in the specified range of object. Leaves page
821 * on whatever queue it is currently on. If NOSYNC is set then do not
822 * write out pages with VPO_NOSYNC set (originally comes from MAP_NOSYNC),
823 * leaving the object dirty.
825 * When stuffing pages asynchronously, allow clustering. XXX we need a
826 * synchronous clustering mode implementation.
828 * Odd semantics: if start == end, we clean everything.
830 * The object must be locked.
832 * Returns FALSE if some page from the range was not written, as
833 * reported by the pager, and TRUE otherwise.
836 vm_object_page_clean(vm_object_t object, vm_ooffset_t start, vm_ooffset_t end,
840 vm_pindex_t pi, tend, tstart;
841 int curgeneration, n, pagerflags;
842 boolean_t clearobjflags, eio, res;
844 VM_OBJECT_ASSERT_WLOCKED(object);
847 * The OBJ_MIGHTBEDIRTY flag is only set for OBJT_VNODE
848 * objects. The check below prevents the function from
849 * operating on non-vnode objects.
851 if ((object->flags & OBJ_MIGHTBEDIRTY) == 0 ||
852 object->resident_page_count == 0)
855 pagerflags = (flags & (OBJPC_SYNC | OBJPC_INVAL)) != 0 ?
856 VM_PAGER_PUT_SYNC : VM_PAGER_CLUSTER_OK;
857 pagerflags |= (flags & OBJPC_INVAL) != 0 ? VM_PAGER_PUT_INVAL : 0;
859 tstart = OFF_TO_IDX(start);
860 tend = (end == 0) ? object->size : OFF_TO_IDX(end + PAGE_MASK);
861 clearobjflags = tstart == 0 && tend >= object->size;
865 curgeneration = object->generation;
867 for (p = vm_page_find_least(object, tstart); p != NULL; p = np) {
871 np = TAILQ_NEXT(p, listq);
874 if (vm_page_sleep_if_busy(p, TRUE, "vpcwai")) {
875 if (object->generation != curgeneration) {
876 if ((flags & OBJPC_SYNC) != 0)
879 clearobjflags = FALSE;
881 np = vm_page_find_least(object, pi);
884 if (!vm_object_page_remove_write(p, flags, &clearobjflags))
887 n = vm_object_page_collect_flush(object, p, pagerflags,
888 flags, &clearobjflags, &eio);
891 clearobjflags = FALSE;
893 if (object->generation != curgeneration) {
894 if ((flags & OBJPC_SYNC) != 0)
897 clearobjflags = FALSE;
901 * If the VOP_PUTPAGES() did a truncated write, so
902 * that even the first page of the run is not fully
903 * written, vm_pageout_flush() returns 0 as the run
904 * length. Since the condition that caused truncated
905 * write may be permanent, e.g. exhausted free space,
906 * accepting n == 0 would cause an infinite loop.
908 * Forwarding the iterator leaves the unwritten page
909 * behind, but there is not much we can do there if
910 * filesystem refuses to write it.
914 clearobjflags = FALSE;
916 np = vm_page_find_least(object, pi + n);
919 VOP_FSYNC(vp, (pagerflags & VM_PAGER_PUT_SYNC) ? MNT_WAIT : 0);
923 vm_object_clear_flag(object, OBJ_MIGHTBEDIRTY);
928 vm_object_page_collect_flush(vm_object_t object, vm_page_t p, int pagerflags,
929 int flags, boolean_t *clearobjflags, boolean_t *eio)
931 vm_page_t ma[vm_pageout_page_count], p_first, tp;
932 int count, i, mreq, runlen;
934 vm_page_lock_assert(p, MA_NOTOWNED);
935 VM_OBJECT_ASSERT_WLOCKED(object);
940 for (tp = p; count < vm_pageout_page_count; count++) {
941 tp = vm_page_next(tp);
942 if (tp == NULL || tp->busy != 0 || (tp->oflags & VPO_BUSY) != 0)
944 if (!vm_object_page_remove_write(tp, flags, clearobjflags))
948 for (p_first = p; count < vm_pageout_page_count; count++) {
949 tp = vm_page_prev(p_first);
950 if (tp == NULL || tp->busy != 0 || (tp->oflags & VPO_BUSY) != 0)
952 if (!vm_object_page_remove_write(tp, flags, clearobjflags))
958 for (tp = p_first, i = 0; i < count; tp = TAILQ_NEXT(tp, listq), i++)
961 vm_pageout_flush(ma, count, pagerflags, mreq, &runlen, eio);
966 * Note that there is absolutely no sense in writing out
967 * anonymous objects, so we track down the vnode object
969 * We invalidate (remove) all pages from the address space
970 * for semantic correctness.
972 * If the backing object is a device object with unmanaged pages, then any
973 * mappings to the specified range of pages must be removed before this
974 * function is called.
976 * Note: certain anonymous maps, such as MAP_NOSYNC maps,
977 * may start out with a NULL object.
980 vm_object_sync(vm_object_t object, vm_ooffset_t offset, vm_size_t size,
981 boolean_t syncio, boolean_t invalidate)
983 vm_object_t backing_object;
986 int error, flags, fsync_after;
993 VM_OBJECT_WLOCK(object);
994 while ((backing_object = object->backing_object) != NULL) {
995 VM_OBJECT_WLOCK(backing_object);
996 offset += object->backing_object_offset;
997 VM_OBJECT_WUNLOCK(object);
998 object = backing_object;
999 if (object->size < OFF_TO_IDX(offset + size))
1000 size = IDX_TO_OFF(object->size) - offset;
1003 * Flush pages if writing is allowed, invalidate them
1004 * if invalidation requested. Pages undergoing I/O
1005 * will be ignored by vm_object_page_remove().
1007 * We cannot lock the vnode and then wait for paging
1008 * to complete without deadlocking against vm_fault.
1009 * Instead we simply call vm_object_page_remove() and
1010 * allow it to block internally on a page-by-page
1011 * basis when it encounters pages undergoing async
1014 if (object->type == OBJT_VNODE &&
1015 (object->flags & OBJ_MIGHTBEDIRTY) != 0) {
1016 vp = object->handle;
1017 VM_OBJECT_WUNLOCK(object);
1018 (void) vn_start_write(vp, &mp, V_WAIT);
1019 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
1020 if (syncio && !invalidate && offset == 0 &&
1021 OFF_TO_IDX(size) == object->size) {
1023 * If syncing the whole mapping of the file,
1024 * it is faster to schedule all the writes in
1025 * async mode, also allowing the clustering,
1026 * and then wait for i/o to complete.
1031 flags = (syncio || invalidate) ? OBJPC_SYNC : 0;
1032 flags |= invalidate ? (OBJPC_SYNC | OBJPC_INVAL) : 0;
1033 fsync_after = FALSE;
1035 VM_OBJECT_WLOCK(object);
1036 res = vm_object_page_clean(object, offset, offset + size,
1038 VM_OBJECT_WUNLOCK(object);
1040 error = VOP_FSYNC(vp, MNT_WAIT, curthread);
1042 vn_finished_write(mp);
1045 VM_OBJECT_WLOCK(object);
1047 if ((object->type == OBJT_VNODE ||
1048 object->type == OBJT_DEVICE) && invalidate) {
1049 if (object->type == OBJT_DEVICE)
1051 * The option OBJPR_NOTMAPPED must be passed here
1052 * because vm_object_page_remove() cannot remove
1053 * unmanaged mappings.
1055 flags = OBJPR_NOTMAPPED;
1057 flags = OBJPR_NOTWIRED;
1059 flags = OBJPR_CLEANONLY | OBJPR_NOTWIRED;
1060 vm_object_page_remove(object, OFF_TO_IDX(offset),
1061 OFF_TO_IDX(offset + size + PAGE_MASK), flags);
1063 VM_OBJECT_WUNLOCK(object);
1068 * vm_object_madvise:
1070 * Implements the madvise function at the object/page level.
1072 * MADV_WILLNEED (any object)
1074 * Activate the specified pages if they are resident.
1076 * MADV_DONTNEED (any object)
1078 * Deactivate the specified pages if they are resident.
1080 * MADV_FREE (OBJT_DEFAULT/OBJT_SWAP objects,
1081 * OBJ_ONEMAPPING only)
1083 * Deactivate and clean the specified pages if they are
1084 * resident. This permits the process to reuse the pages
1085 * without faulting or the kernel to reclaim the pages
1089 vm_object_madvise(vm_object_t object, vm_pindex_t pindex, vm_pindex_t end,
1092 vm_pindex_t tpindex;
1093 vm_object_t backing_object, tobject;
1098 VM_OBJECT_WLOCK(object);
1100 * Locate and adjust resident pages
1102 for (; pindex < end; pindex += 1) {
1108 * MADV_FREE only operates on OBJT_DEFAULT or OBJT_SWAP pages
1109 * and those pages must be OBJ_ONEMAPPING.
1111 if (advise == MADV_FREE) {
1112 if ((tobject->type != OBJT_DEFAULT &&
1113 tobject->type != OBJT_SWAP) ||
1114 (tobject->flags & OBJ_ONEMAPPING) == 0) {
1115 goto unlock_tobject;
1117 } else if ((tobject->flags & OBJ_UNMANAGED) != 0)
1118 goto unlock_tobject;
1119 m = vm_page_lookup(tobject, tpindex);
1120 if (m == NULL && advise == MADV_WILLNEED) {
1122 * If the page is cached, reactivate it.
1124 m = vm_page_alloc(tobject, tpindex, VM_ALLOC_IFCACHED |
1129 * There may be swap even if there is no backing page
1131 if (advise == MADV_FREE && tobject->type == OBJT_SWAP)
1132 swap_pager_freespace(tobject, tpindex, 1);
1136 backing_object = tobject->backing_object;
1137 if (backing_object == NULL)
1138 goto unlock_tobject;
1139 VM_OBJECT_WLOCK(backing_object);
1140 tpindex += OFF_TO_IDX(tobject->backing_object_offset);
1141 if (tobject != object)
1142 VM_OBJECT_WUNLOCK(tobject);
1143 tobject = backing_object;
1145 } else if (m->valid != VM_PAGE_BITS_ALL)
1146 goto unlock_tobject;
1148 * If the page is not in a normal state, skip it.
1151 if (m->hold_count != 0 || m->wire_count != 0) {
1153 goto unlock_tobject;
1155 KASSERT((m->flags & PG_FICTITIOUS) == 0,
1156 ("vm_object_madvise: page %p is fictitious", m));
1157 KASSERT((m->oflags & VPO_UNMANAGED) == 0,
1158 ("vm_object_madvise: page %p is not managed", m));
1159 if ((m->oflags & VPO_BUSY) || m->busy) {
1160 if (advise == MADV_WILLNEED) {
1162 * Reference the page before unlocking and
1163 * sleeping so that the page daemon is less
1164 * likely to reclaim it.
1166 vm_page_aflag_set(m, PGA_REFERENCED);
1169 if (object != tobject)
1170 VM_OBJECT_WUNLOCK(object);
1171 m->oflags |= VPO_WANTED;
1172 VM_OBJECT_SLEEP(tobject, m, PDROP | PVM, "madvpo", 0);
1173 VM_OBJECT_WLOCK(object);
1176 if (advise == MADV_WILLNEED) {
1177 vm_page_activate(m);
1179 vm_page_advise(m, advise);
1182 if (advise == MADV_FREE && tobject->type == OBJT_SWAP)
1183 swap_pager_freespace(tobject, tpindex, 1);
1185 if (tobject != object)
1186 VM_OBJECT_WUNLOCK(tobject);
1188 VM_OBJECT_WUNLOCK(object);
1194 * Create a new object which is backed by the
1195 * specified existing object range. The source
1196 * object reference is deallocated.
1198 * The new object and offset into that object
1199 * are returned in the source parameters.
1203 vm_object_t *object, /* IN/OUT */
1204 vm_ooffset_t *offset, /* IN/OUT */
1213 * Don't create the new object if the old object isn't shared.
1215 if (source != NULL) {
1216 VM_OBJECT_WLOCK(source);
1217 if (source->ref_count == 1 &&
1218 source->handle == NULL &&
1219 (source->type == OBJT_DEFAULT ||
1220 source->type == OBJT_SWAP)) {
1221 VM_OBJECT_WUNLOCK(source);
1224 VM_OBJECT_WUNLOCK(source);
1228 * Allocate a new object with the given length.
1230 result = vm_object_allocate(OBJT_DEFAULT, atop(length));
1233 * The new object shadows the source object, adding a reference to it.
1234 * Our caller changes his reference to point to the new object,
1235 * removing a reference to the source object. Net result: no change
1236 * of reference count.
1238 * Try to optimize the result object's page color when shadowing
1239 * in order to maintain page coloring consistency in the combined
1242 result->backing_object = source;
1244 * Store the offset into the source object, and fix up the offset into
1247 result->backing_object_offset = *offset;
1248 if (source != NULL) {
1249 VM_OBJECT_WLOCK(source);
1250 LIST_INSERT_HEAD(&source->shadow_head, result, shadow_list);
1251 source->shadow_count++;
1252 #if VM_NRESERVLEVEL > 0
1253 result->flags |= source->flags & OBJ_COLORED;
1254 result->pg_color = (source->pg_color + OFF_TO_IDX(*offset)) &
1255 ((1 << (VM_NFREEORDER - 1)) - 1);
1257 VM_OBJECT_WUNLOCK(source);
1262 * Return the new things
1271 * Split the pages in a map entry into a new object. This affords
1272 * easier removal of unused pages, and keeps object inheritance from
1273 * being a negative impact on memory usage.
1276 vm_object_split(vm_map_entry_t entry)
1278 vm_page_t m, m_next;
1279 vm_object_t orig_object, new_object, source;
1280 vm_pindex_t idx, offidxstart;
1283 orig_object = entry->object.vm_object;
1284 if (orig_object->type != OBJT_DEFAULT && orig_object->type != OBJT_SWAP)
1286 if (orig_object->ref_count <= 1)
1288 VM_OBJECT_WUNLOCK(orig_object);
1290 offidxstart = OFF_TO_IDX(entry->offset);
1291 size = atop(entry->end - entry->start);
1294 * If swap_pager_copy() is later called, it will convert new_object
1295 * into a swap object.
1297 new_object = vm_object_allocate(OBJT_DEFAULT, size);
1300 * At this point, the new object is still private, so the order in
1301 * which the original and new objects are locked does not matter.
1303 VM_OBJECT_WLOCK(new_object);
1304 VM_OBJECT_WLOCK(orig_object);
1305 source = orig_object->backing_object;
1306 if (source != NULL) {
1307 VM_OBJECT_WLOCK(source);
1308 if ((source->flags & OBJ_DEAD) != 0) {
1309 VM_OBJECT_WUNLOCK(source);
1310 VM_OBJECT_WUNLOCK(orig_object);
1311 VM_OBJECT_WUNLOCK(new_object);
1312 vm_object_deallocate(new_object);
1313 VM_OBJECT_WLOCK(orig_object);
1316 LIST_INSERT_HEAD(&source->shadow_head,
1317 new_object, shadow_list);
1318 source->shadow_count++;
1319 vm_object_reference_locked(source); /* for new_object */
1320 vm_object_clear_flag(source, OBJ_ONEMAPPING);
1321 VM_OBJECT_WUNLOCK(source);
1322 new_object->backing_object_offset =
1323 orig_object->backing_object_offset + entry->offset;
1324 new_object->backing_object = source;
1326 if (orig_object->cred != NULL) {
1327 new_object->cred = orig_object->cred;
1328 crhold(orig_object->cred);
1329 new_object->charge = ptoa(size);
1330 KASSERT(orig_object->charge >= ptoa(size),
1331 ("orig_object->charge < 0"));
1332 orig_object->charge -= ptoa(size);
1335 m = vm_page_find_least(orig_object, offidxstart);
1336 for (; m != NULL && (idx = m->pindex - offidxstart) < size;
1338 m_next = TAILQ_NEXT(m, listq);
1341 * We must wait for pending I/O to complete before we can
1344 * We do not have to VM_PROT_NONE the page as mappings should
1345 * not be changed by this operation.
1347 if ((m->oflags & VPO_BUSY) || m->busy) {
1348 VM_OBJECT_WUNLOCK(new_object);
1349 m->oflags |= VPO_WANTED;
1350 VM_OBJECT_SLEEP(orig_object, m, PVM, "spltwt", 0);
1351 VM_OBJECT_WLOCK(new_object);
1354 #if VM_NRESERVLEVEL > 0
1356 * If some of the reservation's allocated pages remain with
1357 * the original object, then transferring the reservation to
1358 * the new object is neither particularly beneficial nor
1359 * particularly harmful as compared to leaving the reservation
1360 * with the original object. If, however, all of the
1361 * reservation's allocated pages are transferred to the new
1362 * object, then transferring the reservation is typically
1363 * beneficial. Determining which of these two cases applies
1364 * would be more costly than unconditionally renaming the
1367 vm_reserv_rename(m, new_object, orig_object, offidxstart);
1370 vm_page_rename(m, new_object, idx);
1372 /* page automatically made dirty by rename and cache handled */
1373 if (orig_object->type == OBJT_SWAP)
1376 if (orig_object->type == OBJT_SWAP) {
1378 * swap_pager_copy() can sleep, in which case the orig_object's
1379 * and new_object's locks are released and reacquired.
1381 swap_pager_copy(orig_object, new_object, offidxstart, 0);
1382 TAILQ_FOREACH(m, &new_object->memq, listq)
1386 * Transfer any cached pages from orig_object to new_object.
1387 * If swap_pager_copy() found swapped out pages within the
1388 * specified range of orig_object, then it changed
1389 * new_object's type to OBJT_SWAP when it transferred those
1390 * pages to new_object. Otherwise, new_object's type
1391 * should still be OBJT_DEFAULT and orig_object should not
1392 * contain any cached pages within the specified range.
1394 if (__predict_false(!vm_object_cache_is_empty(orig_object)))
1395 vm_page_cache_transfer(orig_object, offidxstart,
1398 VM_OBJECT_WUNLOCK(orig_object);
1399 VM_OBJECT_WUNLOCK(new_object);
1400 entry->object.vm_object = new_object;
1401 entry->offset = 0LL;
1402 vm_object_deallocate(orig_object);
1403 VM_OBJECT_WLOCK(new_object);
1406 #define OBSC_TEST_ALL_SHADOWED 0x0001
1407 #define OBSC_COLLAPSE_NOWAIT 0x0002
1408 #define OBSC_COLLAPSE_WAIT 0x0004
1411 vm_object_backing_scan(vm_object_t object, int op)
1415 vm_object_t backing_object;
1416 vm_pindex_t backing_offset_index;
1418 VM_OBJECT_ASSERT_WLOCKED(object);
1419 VM_OBJECT_ASSERT_WLOCKED(object->backing_object);
1421 backing_object = object->backing_object;
1422 backing_offset_index = OFF_TO_IDX(object->backing_object_offset);
1425 * Initial conditions
1427 if (op & OBSC_TEST_ALL_SHADOWED) {
1429 * We do not want to have to test for the existence of cache
1430 * or swap pages in the backing object. XXX but with the
1431 * new swapper this would be pretty easy to do.
1433 * XXX what about anonymous MAP_SHARED memory that hasn't
1434 * been ZFOD faulted yet? If we do not test for this, the
1435 * shadow test may succeed! XXX
1437 if (backing_object->type != OBJT_DEFAULT) {
1441 if (op & OBSC_COLLAPSE_WAIT) {
1442 vm_object_set_flag(backing_object, OBJ_DEAD);
1448 p = TAILQ_FIRST(&backing_object->memq);
1450 vm_page_t next = TAILQ_NEXT(p, listq);
1451 vm_pindex_t new_pindex = p->pindex - backing_offset_index;
1453 if (op & OBSC_TEST_ALL_SHADOWED) {
1457 * Ignore pages outside the parent object's range
1458 * and outside the parent object's mapping of the
1461 * note that we do not busy the backing object's
1465 p->pindex < backing_offset_index ||
1466 new_pindex >= object->size
1473 * See if the parent has the page or if the parent's
1474 * object pager has the page. If the parent has the
1475 * page but the page is not valid, the parent's
1476 * object pager must have the page.
1478 * If this fails, the parent does not completely shadow
1479 * the object and we might as well give up now.
1482 pp = vm_page_lookup(object, new_pindex);
1484 (pp == NULL || pp->valid == 0) &&
1485 !vm_pager_has_page(object, new_pindex, NULL, NULL)
1493 * Check for busy page
1495 if (op & (OBSC_COLLAPSE_WAIT | OBSC_COLLAPSE_NOWAIT)) {
1498 if (op & OBSC_COLLAPSE_NOWAIT) {
1499 if ((p->oflags & VPO_BUSY) ||
1505 } else if (op & OBSC_COLLAPSE_WAIT) {
1506 if ((p->oflags & VPO_BUSY) || p->busy) {
1507 VM_OBJECT_WUNLOCK(object);
1508 p->oflags |= VPO_WANTED;
1509 VM_OBJECT_SLEEP(backing_object, p,
1510 PDROP | PVM, "vmocol", 0);
1511 VM_OBJECT_WLOCK(object);
1512 VM_OBJECT_WLOCK(backing_object);
1514 * If we slept, anything could have
1515 * happened. Since the object is
1516 * marked dead, the backing offset
1517 * should not have changed so we
1518 * just restart our scan.
1520 p = TAILQ_FIRST(&backing_object->memq);
1526 p->object == backing_object,
1527 ("vm_object_backing_scan: object mismatch")
1531 * Destroy any associated swap
1533 if (backing_object->type == OBJT_SWAP) {
1534 swap_pager_freespace(
1542 p->pindex < backing_offset_index ||
1543 new_pindex >= object->size
1546 * Page is out of the parent object's range, we
1547 * can simply destroy it.
1550 KASSERT(!pmap_page_is_mapped(p),
1551 ("freeing mapped page %p", p));
1552 if (p->wire_count == 0)
1561 pp = vm_page_lookup(object, new_pindex);
1563 (op & OBSC_COLLAPSE_NOWAIT) != 0 &&
1564 (pp != NULL && pp->valid == 0)
1567 * The page in the parent is not (yet) valid.
1568 * We don't know anything about the state of
1569 * the original page. It might be mapped,
1570 * so we must avoid the next if here.
1572 * This is due to a race in vm_fault() where
1573 * we must unbusy the original (backing_obj)
1574 * page before we can (re)lock the parent.
1575 * Hence we can get here.
1582 vm_pager_has_page(object, new_pindex, NULL, NULL)
1585 * page already exists in parent OR swap exists
1586 * for this location in the parent. Destroy
1587 * the original page from the backing object.
1589 * Leave the parent's page alone
1592 KASSERT(!pmap_page_is_mapped(p),
1593 ("freeing mapped page %p", p));
1594 if (p->wire_count == 0)
1603 #if VM_NRESERVLEVEL > 0
1605 * Rename the reservation.
1607 vm_reserv_rename(p, object, backing_object,
1608 backing_offset_index);
1612 * Page does not exist in parent, rename the
1613 * page from the backing object to the main object.
1615 * If the page was mapped to a process, it can remain
1616 * mapped through the rename.
1619 vm_page_rename(p, object, new_pindex);
1621 /* page automatically made dirty by rename */
1630 * this version of collapse allows the operation to occur earlier and
1631 * when paging_in_progress is true for an object... This is not a complete
1632 * operation, but should plug 99.9% of the rest of the leaks.
1635 vm_object_qcollapse(vm_object_t object)
1637 vm_object_t backing_object = object->backing_object;
1639 VM_OBJECT_ASSERT_WLOCKED(object);
1640 VM_OBJECT_ASSERT_WLOCKED(backing_object);
1642 if (backing_object->ref_count != 1)
1645 vm_object_backing_scan(object, OBSC_COLLAPSE_NOWAIT);
1649 * vm_object_collapse:
1651 * Collapse an object with the object backing it.
1652 * Pages in the backing object are moved into the
1653 * parent, and the backing object is deallocated.
1656 vm_object_collapse(vm_object_t object)
1658 VM_OBJECT_ASSERT_WLOCKED(object);
1661 vm_object_t backing_object;
1664 * Verify that the conditions are right for collapse:
1666 * The object exists and the backing object exists.
1668 if ((backing_object = object->backing_object) == NULL)
1672 * we check the backing object first, because it is most likely
1675 VM_OBJECT_WLOCK(backing_object);
1676 if (backing_object->handle != NULL ||
1677 (backing_object->type != OBJT_DEFAULT &&
1678 backing_object->type != OBJT_SWAP) ||
1679 (backing_object->flags & OBJ_DEAD) ||
1680 object->handle != NULL ||
1681 (object->type != OBJT_DEFAULT &&
1682 object->type != OBJT_SWAP) ||
1683 (object->flags & OBJ_DEAD)) {
1684 VM_OBJECT_WUNLOCK(backing_object);
1689 object->paging_in_progress != 0 ||
1690 backing_object->paging_in_progress != 0
1692 vm_object_qcollapse(object);
1693 VM_OBJECT_WUNLOCK(backing_object);
1697 * We know that we can either collapse the backing object (if
1698 * the parent is the only reference to it) or (perhaps) have
1699 * the parent bypass the object if the parent happens to shadow
1700 * all the resident pages in the entire backing object.
1702 * This is ignoring pager-backed pages such as swap pages.
1703 * vm_object_backing_scan fails the shadowing test in this
1706 if (backing_object->ref_count == 1) {
1708 * If there is exactly one reference to the backing
1709 * object, we can collapse it into the parent.
1711 vm_object_backing_scan(object, OBSC_COLLAPSE_WAIT);
1713 #if VM_NRESERVLEVEL > 0
1715 * Break any reservations from backing_object.
1717 if (__predict_false(!LIST_EMPTY(&backing_object->rvq)))
1718 vm_reserv_break_all(backing_object);
1722 * Move the pager from backing_object to object.
1724 if (backing_object->type == OBJT_SWAP) {
1726 * swap_pager_copy() can sleep, in which case
1727 * the backing_object's and object's locks are
1728 * released and reacquired.
1729 * Since swap_pager_copy() is being asked to
1730 * destroy the source, it will change the
1731 * backing_object's type to OBJT_DEFAULT.
1736 OFF_TO_IDX(object->backing_object_offset), TRUE);
1739 * Free any cached pages from backing_object.
1741 if (__predict_false(
1742 !vm_object_cache_is_empty(backing_object)))
1743 vm_page_cache_free(backing_object, 0, 0);
1746 * Object now shadows whatever backing_object did.
1747 * Note that the reference to
1748 * backing_object->backing_object moves from within
1749 * backing_object to within object.
1751 LIST_REMOVE(object, shadow_list);
1752 backing_object->shadow_count--;
1753 if (backing_object->backing_object) {
1754 VM_OBJECT_WLOCK(backing_object->backing_object);
1755 LIST_REMOVE(backing_object, shadow_list);
1757 &backing_object->backing_object->shadow_head,
1758 object, shadow_list);
1760 * The shadow_count has not changed.
1762 VM_OBJECT_WUNLOCK(backing_object->backing_object);
1764 object->backing_object = backing_object->backing_object;
1765 object->backing_object_offset +=
1766 backing_object->backing_object_offset;
1769 * Discard backing_object.
1771 * Since the backing object has no pages, no pager left,
1772 * and no object references within it, all that is
1773 * necessary is to dispose of it.
1775 KASSERT(backing_object->ref_count == 1, (
1776 "backing_object %p was somehow re-referenced during collapse!",
1778 VM_OBJECT_WUNLOCK(backing_object);
1779 vm_object_destroy(backing_object);
1783 vm_object_t new_backing_object;
1786 * If we do not entirely shadow the backing object,
1787 * there is nothing we can do so we give up.
1789 if (object->resident_page_count != object->size &&
1790 vm_object_backing_scan(object,
1791 OBSC_TEST_ALL_SHADOWED) == 0) {
1792 VM_OBJECT_WUNLOCK(backing_object);
1797 * Make the parent shadow the next object in the
1798 * chain. Deallocating backing_object will not remove
1799 * it, since its reference count is at least 2.
1801 LIST_REMOVE(object, shadow_list);
1802 backing_object->shadow_count--;
1804 new_backing_object = backing_object->backing_object;
1805 if ((object->backing_object = new_backing_object) != NULL) {
1806 VM_OBJECT_WLOCK(new_backing_object);
1808 &new_backing_object->shadow_head,
1812 new_backing_object->shadow_count++;
1813 vm_object_reference_locked(new_backing_object);
1814 VM_OBJECT_WUNLOCK(new_backing_object);
1815 object->backing_object_offset +=
1816 backing_object->backing_object_offset;
1820 * Drop the reference count on backing_object. Since
1821 * its ref_count was at least 2, it will not vanish.
1823 backing_object->ref_count--;
1824 VM_OBJECT_WUNLOCK(backing_object);
1829 * Try again with this object's new backing object.
1835 * vm_object_page_remove:
1837 * For the given object, either frees or invalidates each of the
1838 * specified pages. In general, a page is freed. However, if a page is
1839 * wired for any reason other than the existence of a managed, wired
1840 * mapping, then it may be invalidated but not removed from the object.
1841 * Pages are specified by the given range ["start", "end") and the option
1842 * OBJPR_CLEANONLY. As a special case, if "end" is zero, then the range
1843 * extends from "start" to the end of the object. If the option
1844 * OBJPR_CLEANONLY is specified, then only the non-dirty pages within the
1845 * specified range are affected. If the option OBJPR_NOTMAPPED is
1846 * specified, then the pages within the specified range must have no
1847 * mappings. Otherwise, if this option is not specified, any mappings to
1848 * the specified pages are removed before the pages are freed or
1851 * In general, this operation should only be performed on objects that
1852 * contain managed pages. There are, however, two exceptions. First, it
1853 * is performed on the kernel and kmem objects by vm_map_entry_delete().
1854 * Second, it is used by msync(..., MS_INVALIDATE) to invalidate device-
1855 * backed pages. In both of these cases, the option OBJPR_CLEANONLY must
1856 * not be specified and the option OBJPR_NOTMAPPED must be specified.
1858 * The object must be locked.
1861 vm_object_page_remove(vm_object_t object, vm_pindex_t start, vm_pindex_t end,
1867 VM_OBJECT_ASSERT_WLOCKED(object);
1868 KASSERT((object->flags & OBJ_UNMANAGED) == 0 ||
1869 (options & (OBJPR_CLEANONLY | OBJPR_NOTMAPPED)) == OBJPR_NOTMAPPED,
1870 ("vm_object_page_remove: illegal options for object %p", object));
1871 if (object->resident_page_count == 0)
1873 vm_object_pip_add(object, 1);
1875 p = vm_page_find_least(object, start);
1878 * Here, the variable "p" is either (1) the page with the least pindex
1879 * greater than or equal to the parameter "start" or (2) NULL.
1881 for (; p != NULL && (p->pindex < end || end == 0); p = next) {
1882 next = TAILQ_NEXT(p, listq);
1885 * If the page is wired for any reason besides the existence
1886 * of managed, wired mappings, then it cannot be freed. For
1887 * example, fictitious pages, which represent device memory,
1888 * are inherently wired and cannot be freed. They can,
1889 * however, be invalidated if the option OBJPR_CLEANONLY is
1893 if ((wirings = p->wire_count) != 0 &&
1894 (wirings = pmap_page_wired_mappings(p)) != p->wire_count) {
1895 if ((options & (OBJPR_NOTWIRED | OBJPR_NOTMAPPED)) ==
1898 /* Account for removal of wired mappings. */
1900 p->wire_count -= wirings;
1902 if ((options & OBJPR_CLEANONLY) == 0) {
1908 if (vm_page_sleep_if_busy(p, TRUE, "vmopar"))
1910 KASSERT((p->flags & PG_FICTITIOUS) == 0,
1911 ("vm_object_page_remove: page %p is fictitious", p));
1912 if ((options & OBJPR_CLEANONLY) != 0 && p->valid != 0) {
1913 if ((options & OBJPR_NOTMAPPED) == 0)
1914 pmap_remove_write(p);
1918 if ((options & OBJPR_NOTMAPPED) == 0) {
1919 if ((options & OBJPR_NOTWIRED) != 0 && wirings != 0)
1922 /* Account for removal of wired mappings. */
1924 KASSERT(p->wire_count == wirings,
1925 ("inconsistent wire count %d %d %p",
1926 p->wire_count, wirings, p));
1928 atomic_subtract_int(&cnt.v_wire_count, 1);
1935 vm_object_pip_wakeup(object);
1937 if (__predict_false(!vm_object_cache_is_empty(object)))
1938 vm_page_cache_free(object, start, end);
1942 * vm_object_page_cache:
1944 * For the given object, attempt to move the specified clean
1945 * pages to the cache queue. If a page is wired for any reason,
1946 * then it will not be changed. Pages are specified by the given
1947 * range ["start", "end"). As a special case, if "end" is zero,
1948 * then the range extends from "start" to the end of the object.
1949 * Any mappings to the specified pages are removed before the
1950 * pages are moved to the cache queue.
1952 * This operation should only be performed on objects that
1953 * contain non-fictitious, managed pages.
1955 * The object must be locked.
1958 vm_object_page_cache(vm_object_t object, vm_pindex_t start, vm_pindex_t end)
1960 struct mtx *mtx, *new_mtx;
1963 VM_OBJECT_ASSERT_WLOCKED(object);
1964 KASSERT((object->flags & (OBJ_FICTITIOUS | OBJ_UNMANAGED)) == 0,
1965 ("vm_object_page_cache: illegal object %p", object));
1966 if (object->resident_page_count == 0)
1968 p = vm_page_find_least(object, start);
1971 * Here, the variable "p" is either (1) the page with the least pindex
1972 * greater than or equal to the parameter "start" or (2) NULL.
1975 for (; p != NULL && (p->pindex < end || end == 0); p = next) {
1976 next = TAILQ_NEXT(p, listq);
1979 * Avoid releasing and reacquiring the same page lock.
1981 new_mtx = vm_page_lockptr(p);
1982 if (mtx != new_mtx) {
1988 vm_page_try_to_cache(p);
1995 * Populate the specified range of the object with valid pages. Returns
1996 * TRUE if the range is successfully populated and FALSE otherwise.
1998 * Note: This function should be optimized to pass a larger array of
1999 * pages to vm_pager_get_pages() before it is applied to a non-
2000 * OBJT_DEVICE object.
2002 * The object must be locked.
2005 vm_object_populate(vm_object_t object, vm_pindex_t start, vm_pindex_t end)
2011 VM_OBJECT_ASSERT_WLOCKED(object);
2012 for (pindex = start; pindex < end; pindex++) {
2013 m = vm_page_grab(object, pindex, VM_ALLOC_NORMAL |
2015 if (m->valid != VM_PAGE_BITS_ALL) {
2017 rv = vm_pager_get_pages(object, ma, 1, 0);
2018 m = vm_page_lookup(object, pindex);
2021 if (rv != VM_PAGER_OK) {
2029 * Keep "m" busy because a subsequent iteration may unlock
2033 if (pindex > start) {
2034 m = vm_page_lookup(object, start);
2035 while (m != NULL && m->pindex < pindex) {
2037 m = TAILQ_NEXT(m, listq);
2040 return (pindex == end);
2044 * Routine: vm_object_coalesce
2045 * Function: Coalesces two objects backing up adjoining
2046 * regions of memory into a single object.
2048 * returns TRUE if objects were combined.
2050 * NOTE: Only works at the moment if the second object is NULL -
2051 * if it's not, which object do we lock first?
2054 * prev_object First object to coalesce
2055 * prev_offset Offset into prev_object
2056 * prev_size Size of reference to prev_object
2057 * next_size Size of reference to the second object
2058 * reserved Indicator that extension region has
2059 * swap accounted for
2062 * The object must *not* be locked.
2065 vm_object_coalesce(vm_object_t prev_object, vm_ooffset_t prev_offset,
2066 vm_size_t prev_size, vm_size_t next_size, boolean_t reserved)
2068 vm_pindex_t next_pindex;
2070 if (prev_object == NULL)
2072 VM_OBJECT_WLOCK(prev_object);
2073 if (prev_object->type != OBJT_DEFAULT &&
2074 prev_object->type != OBJT_SWAP) {
2075 VM_OBJECT_WUNLOCK(prev_object);
2080 * Try to collapse the object first
2082 vm_object_collapse(prev_object);
2085 * Can't coalesce if: . more than one reference . paged out . shadows
2086 * another object . has a copy elsewhere (any of which mean that the
2087 * pages not mapped to prev_entry may be in use anyway)
2089 if (prev_object->backing_object != NULL) {
2090 VM_OBJECT_WUNLOCK(prev_object);
2094 prev_size >>= PAGE_SHIFT;
2095 next_size >>= PAGE_SHIFT;
2096 next_pindex = OFF_TO_IDX(prev_offset) + prev_size;
2098 if ((prev_object->ref_count > 1) &&
2099 (prev_object->size != next_pindex)) {
2100 VM_OBJECT_WUNLOCK(prev_object);
2105 * Account for the charge.
2107 if (prev_object->cred != NULL) {
2110 * If prev_object was charged, then this mapping,
2111 * althought not charged now, may become writable
2112 * later. Non-NULL cred in the object would prevent
2113 * swap reservation during enabling of the write
2114 * access, so reserve swap now. Failed reservation
2115 * cause allocation of the separate object for the map
2116 * entry, and swap reservation for this entry is
2117 * managed in appropriate time.
2119 if (!reserved && !swap_reserve_by_cred(ptoa(next_size),
2120 prev_object->cred)) {
2123 prev_object->charge += ptoa(next_size);
2127 * Remove any pages that may still be in the object from a previous
2130 if (next_pindex < prev_object->size) {
2131 vm_object_page_remove(prev_object, next_pindex, next_pindex +
2133 if (prev_object->type == OBJT_SWAP)
2134 swap_pager_freespace(prev_object,
2135 next_pindex, next_size);
2137 if (prev_object->cred != NULL) {
2138 KASSERT(prev_object->charge >=
2139 ptoa(prev_object->size - next_pindex),
2140 ("object %p overcharged 1 %jx %jx", prev_object,
2141 (uintmax_t)next_pindex, (uintmax_t)next_size));
2142 prev_object->charge -= ptoa(prev_object->size -
2149 * Extend the object if necessary.
2151 if (next_pindex + next_size > prev_object->size)
2152 prev_object->size = next_pindex + next_size;
2154 VM_OBJECT_WUNLOCK(prev_object);
2159 vm_object_set_writeable_dirty(vm_object_t object)
2162 VM_OBJECT_ASSERT_WLOCKED(object);
2163 if (object->type != OBJT_VNODE)
2165 object->generation++;
2166 if ((object->flags & OBJ_MIGHTBEDIRTY) != 0)
2168 vm_object_set_flag(object, OBJ_MIGHTBEDIRTY);
2171 #include "opt_ddb.h"
2173 #include <sys/kernel.h>
2175 #include <sys/cons.h>
2177 #include <ddb/ddb.h>
2180 _vm_object_in_map(vm_map_t map, vm_object_t object, vm_map_entry_t entry)
2183 vm_map_entry_t tmpe;
2191 tmpe = map->header.next;
2192 entcount = map->nentries;
2193 while (entcount-- && (tmpe != &map->header)) {
2194 if (_vm_object_in_map(map, object, tmpe)) {
2199 } else if (entry->eflags & MAP_ENTRY_IS_SUB_MAP) {
2200 tmpm = entry->object.sub_map;
2201 tmpe = tmpm->header.next;
2202 entcount = tmpm->nentries;
2203 while (entcount-- && tmpe != &tmpm->header) {
2204 if (_vm_object_in_map(tmpm, object, tmpe)) {
2209 } else if ((obj = entry->object.vm_object) != NULL) {
2210 for (; obj; obj = obj->backing_object)
2211 if (obj == object) {
2219 vm_object_in_map(vm_object_t object)
2223 /* sx_slock(&allproc_lock); */
2224 FOREACH_PROC_IN_SYSTEM(p) {
2225 if (!p->p_vmspace /* || (p->p_flag & (P_SYSTEM|P_WEXIT)) */)
2227 if (_vm_object_in_map(&p->p_vmspace->vm_map, object, 0)) {
2228 /* sx_sunlock(&allproc_lock); */
2232 /* sx_sunlock(&allproc_lock); */
2233 if (_vm_object_in_map(kernel_map, object, 0))
2238 DB_SHOW_COMMAND(vmochk, vm_object_check)
2243 * make sure that internal objs are in a map somewhere
2244 * and none have zero ref counts.
2246 TAILQ_FOREACH(object, &vm_object_list, object_list) {
2247 if (object->handle == NULL &&
2248 (object->type == OBJT_DEFAULT || object->type == OBJT_SWAP)) {
2249 if (object->ref_count == 0) {
2250 db_printf("vmochk: internal obj has zero ref count: %ld\n",
2251 (long)object->size);
2253 if (!vm_object_in_map(object)) {
2255 "vmochk: internal obj is not in a map: "
2256 "ref: %d, size: %lu: 0x%lx, backing_object: %p\n",
2257 object->ref_count, (u_long)object->size,
2258 (u_long)object->size,
2259 (void *)object->backing_object);
2266 * vm_object_print: [ debug ]
2268 DB_SHOW_COMMAND(object, vm_object_print_static)
2270 /* XXX convert args. */
2271 vm_object_t object = (vm_object_t)addr;
2272 boolean_t full = have_addr;
2276 /* XXX count is an (unused) arg. Avoid shadowing it. */
2277 #define count was_count
2285 "Object %p: type=%d, size=0x%jx, res=%d, ref=%d, flags=0x%x ruid %d charge %jx\n",
2286 object, (int)object->type, (uintmax_t)object->size,
2287 object->resident_page_count, object->ref_count, object->flags,
2288 object->cred ? object->cred->cr_ruid : -1, (uintmax_t)object->charge);
2289 db_iprintf(" sref=%d, backing_object(%d)=(%p)+0x%jx\n",
2290 object->shadow_count,
2291 object->backing_object ? object->backing_object->ref_count : 0,
2292 object->backing_object, (uintmax_t)object->backing_object_offset);
2299 TAILQ_FOREACH(p, &object->memq, listq) {
2301 db_iprintf("memory:=");
2302 else if (count == 6) {
2310 db_printf("(off=0x%jx,page=0x%jx)",
2311 (uintmax_t)p->pindex, (uintmax_t)VM_PAGE_TO_PHYS(p));
2321 /* XXX need this non-static entry for calling from vm_map_print. */
2324 /* db_expr_t */ long addr,
2325 boolean_t have_addr,
2326 /* db_expr_t */ long count,
2329 vm_object_print_static(addr, have_addr, count, modif);
2332 DB_SHOW_COMMAND(vmopag, vm_object_print_pages)
2337 vm_page_t m, prev_m;
2341 TAILQ_FOREACH(object, &vm_object_list, object_list) {
2342 db_printf("new object: %p\n", (void *)object);
2353 TAILQ_FOREACH(m, &object->memq, listq) {
2354 if (m->pindex > 128)
2356 if ((prev_m = TAILQ_PREV(m, pglist, listq)) != NULL &&
2357 prev_m->pindex + 1 != m->pindex) {
2359 db_printf(" index(%ld)run(%d)pa(0x%lx)\n",
2360 (long)fidx, rcount, (long)pa);
2372 (VM_PAGE_TO_PHYS(m) == pa + rcount * PAGE_SIZE)) {
2377 db_printf(" index(%ld)run(%d)pa(0x%lx)\n",
2378 (long)fidx, rcount, (long)pa);
2388 pa = VM_PAGE_TO_PHYS(m);
2392 db_printf(" index(%ld)run(%d)pa(0x%lx)\n",
2393 (long)fidx, rcount, (long)pa);