2 * SPDX-License-Identifier: (BSD-3-Clause AND MIT-CMU)
4 * Copyright (c) 1991, 1993
5 * The Regents of the University of California. All rights reserved.
7 * This code is derived from software contributed to Berkeley by
8 * The Mach Operating System project at Carnegie-Mellon University.
10 * Redistribution and use in source and binary forms, with or without
11 * modification, are permitted provided that the following conditions
13 * 1. Redistributions of source code must retain the above copyright
14 * notice, this list of conditions and the following disclaimer.
15 * 2. Redistributions in binary form must reproduce the above copyright
16 * notice, this list of conditions and the following disclaimer in the
17 * documentation and/or other materials provided with the distribution.
18 * 3. Neither the name of the University nor the names of its contributors
19 * may be used to endorse or promote products derived from this software
20 * without specific prior written permission.
22 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
23 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
24 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
25 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
26 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
27 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
28 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
29 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
30 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
31 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
34 * from: @(#)vm_object.c 8.5 (Berkeley) 3/22/94
37 * Copyright (c) 1987, 1990 Carnegie-Mellon University.
38 * All rights reserved.
40 * Authors: Avadis Tevanian, Jr., Michael Wayne Young
42 * Permission to use, copy, modify and distribute this software and
43 * its documentation is hereby granted, provided that both the copyright
44 * notice and this permission notice appear in all copies of the
45 * software, derivative works or modified versions, and any portions
46 * thereof, and that both notices appear in supporting documentation.
48 * CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS"
49 * CONDITION. CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND
50 * FOR ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
52 * Carnegie Mellon requests users of this software to return to
54 * Software Distribution Coordinator or Software.Distribution@CS.CMU.EDU
55 * School of Computer Science
56 * Carnegie Mellon University
57 * Pittsburgh PA 15213-3890
59 * any improvements or extensions that they make and grant Carnegie the
60 * rights to redistribute these changes.
64 * Virtual memory object module.
67 #include <sys/cdefs.h>
68 __FBSDID("$FreeBSD$");
72 #include <sys/param.h>
73 #include <sys/systm.h>
74 #include <sys/blockcount.h>
75 #include <sys/cpuset.h>
76 #include <sys/limits.h>
79 #include <sys/mount.h>
80 #include <sys/kernel.h>
81 #include <sys/pctrie.h>
82 #include <sys/sysctl.h>
83 #include <sys/mutex.h>
84 #include <sys/proc.h> /* for curproc, pageproc */
85 #include <sys/refcount.h>
86 #include <sys/socket.h>
87 #include <sys/resourcevar.h>
88 #include <sys/refcount.h>
89 #include <sys/rwlock.h>
91 #include <sys/vnode.h>
92 #include <sys/vmmeter.h>
96 #include <vm/vm_param.h>
98 #include <vm/vm_map.h>
99 #include <vm/vm_object.h>
100 #include <vm/vm_page.h>
101 #include <vm/vm_pageout.h>
102 #include <vm/vm_pager.h>
103 #include <vm/vm_phys.h>
104 #include <vm/vm_pagequeue.h>
105 #include <vm/swap_pager.h>
106 #include <vm/vm_kern.h>
107 #include <vm/vm_extern.h>
108 #include <vm/vm_radix.h>
109 #include <vm/vm_reserv.h>
112 static int old_msync;
113 SYSCTL_INT(_vm, OID_AUTO, old_msync, CTLFLAG_RW, &old_msync, 0,
114 "Use old (insecure) msync behavior");
116 static int vm_object_page_collect_flush(vm_object_t object, vm_page_t p,
117 int pagerflags, int flags, boolean_t *allclean,
119 static boolean_t vm_object_page_remove_write(vm_page_t p, int flags,
120 boolean_t *allclean);
121 static void vm_object_backing_remove(vm_object_t object);
124 * Virtual memory objects maintain the actual data
125 * associated with allocated virtual memory. A given
126 * page of memory exists within exactly one object.
128 * An object is only deallocated when all "references"
129 * are given up. Only one "reference" to a given
130 * region of an object should be writeable.
132 * Associated with each object is a list of all resident
133 * memory pages belonging to that object; this list is
134 * maintained by the "vm_page" module, and locked by the object's
137 * Each object also records a "pager" routine which is
138 * used to retrieve (and store) pages to the proper backing
139 * storage. In addition, objects may be backed by other
140 * objects from which they were virtual-copied.
142 * The only items within the object structure which are
143 * modified after time of creation are:
144 * reference count locked by object's lock
145 * pager routine locked by object's lock
149 struct object_q vm_object_list;
150 struct mtx vm_object_list_mtx; /* lock for object list and count */
152 struct vm_object kernel_object_store;
154 static SYSCTL_NODE(_vm_stats, OID_AUTO, object, CTLFLAG_RD | CTLFLAG_MPSAFE, 0,
157 static COUNTER_U64_DEFINE_EARLY(object_collapses);
158 SYSCTL_COUNTER_U64(_vm_stats_object, OID_AUTO, collapses, CTLFLAG_RD,
160 "VM object collapses");
162 static COUNTER_U64_DEFINE_EARLY(object_bypasses);
163 SYSCTL_COUNTER_U64(_vm_stats_object, OID_AUTO, bypasses, CTLFLAG_RD,
165 "VM object bypasses");
167 static COUNTER_U64_DEFINE_EARLY(object_collapse_waits);
168 SYSCTL_COUNTER_U64(_vm_stats_object, OID_AUTO, collapse_waits, CTLFLAG_RD,
169 &object_collapse_waits,
170 "Number of sleeps for collapse");
172 static uma_zone_t obj_zone;
174 static int vm_object_zinit(void *mem, int size, int flags);
177 static void vm_object_zdtor(void *mem, int size, void *arg);
180 vm_object_zdtor(void *mem, int size, void *arg)
184 object = (vm_object_t)mem;
185 KASSERT(object->ref_count == 0,
186 ("object %p ref_count = %d", object, object->ref_count));
187 KASSERT(TAILQ_EMPTY(&object->memq),
188 ("object %p has resident pages in its memq", object));
189 KASSERT(vm_radix_is_empty(&object->rtree),
190 ("object %p has resident pages in its trie", object));
191 #if VM_NRESERVLEVEL > 0
192 KASSERT(LIST_EMPTY(&object->rvq),
193 ("object %p has reservations",
196 KASSERT(!vm_object_busied(object),
197 ("object %p busy = %d", object, blockcount_read(&object->busy)));
198 KASSERT(object->resident_page_count == 0,
199 ("object %p resident_page_count = %d",
200 object, object->resident_page_count));
201 KASSERT(atomic_load_int(&object->shadow_count) == 0,
202 ("object %p shadow_count = %d",
203 object, atomic_load_int(&object->shadow_count)));
204 KASSERT(object->type == OBJT_DEAD,
205 ("object %p has non-dead type %d",
206 object, object->type));
207 KASSERT(object->charge == 0 && object->cred == NULL,
208 ("object %p has non-zero charge %ju (%p)",
209 object, (uintmax_t)object->charge, object->cred));
214 vm_object_zinit(void *mem, int size, int flags)
218 object = (vm_object_t)mem;
219 rw_init_flags(&object->lock, "vmobject", RW_DUPOK | RW_NEW);
221 /* These are true for any object that has been freed */
222 object->type = OBJT_DEAD;
223 vm_radix_init(&object->rtree);
224 refcount_init(&object->ref_count, 0);
225 blockcount_init(&object->paging_in_progress);
226 blockcount_init(&object->busy);
227 object->resident_page_count = 0;
228 atomic_store_int(&object->shadow_count, 0);
229 object->flags = OBJ_DEAD;
231 mtx_lock(&vm_object_list_mtx);
232 TAILQ_INSERT_TAIL(&vm_object_list, object, object_list);
233 mtx_unlock(&vm_object_list_mtx);
238 _vm_object_allocate(objtype_t type, vm_pindex_t size, u_short flags,
239 vm_object_t object, void *handle)
242 TAILQ_INIT(&object->memq);
243 LIST_INIT(&object->shadow_head);
246 object->flags = flags;
247 if ((flags & OBJ_SWAP) != 0) {
248 pctrie_init(&object->un_pager.swp.swp_blks);
249 object->un_pager.swp.writemappings = 0;
253 * Ensure that swap_pager_swapoff() iteration over object_list
254 * sees up to date type and pctrie head if it observed
257 atomic_thread_fence_rel();
259 object->pg_color = 0;
261 object->domain.dr_policy = NULL;
262 object->generation = 1;
263 object->cleangeneration = 1;
264 refcount_init(&object->ref_count, 1);
265 object->memattr = VM_MEMATTR_DEFAULT;
268 object->handle = handle;
269 object->backing_object = NULL;
270 object->backing_object_offset = (vm_ooffset_t) 0;
271 #if VM_NRESERVLEVEL > 0
272 LIST_INIT(&object->rvq);
274 umtx_shm_object_init(object);
280 * Initialize the VM objects module.
285 TAILQ_INIT(&vm_object_list);
286 mtx_init(&vm_object_list_mtx, "vm object_list", NULL, MTX_DEF);
288 rw_init(&kernel_object->lock, "kernel vm object");
289 vm_radix_init(&kernel_object->rtree);
290 _vm_object_allocate(OBJT_PHYS, atop(VM_MAX_KERNEL_ADDRESS -
291 VM_MIN_KERNEL_ADDRESS), OBJ_UNMANAGED, kernel_object, NULL);
292 #if VM_NRESERVLEVEL > 0
293 kernel_object->flags |= OBJ_COLORED;
294 kernel_object->pg_color = (u_short)atop(VM_MIN_KERNEL_ADDRESS);
296 kernel_object->un_pager.phys.ops = &default_phys_pg_ops;
299 * The lock portion of struct vm_object must be type stable due
300 * to vm_pageout_fallback_object_lock locking a vm object
301 * without holding any references to it.
303 * paging_in_progress is valid always. Lockless references to
304 * the objects may acquire pip and then check OBJ_DEAD.
306 obj_zone = uma_zcreate("VM OBJECT", sizeof (struct vm_object), NULL,
312 vm_object_zinit, NULL, UMA_ALIGN_PTR, UMA_ZONE_NOFREE);
318 vm_object_clear_flag(vm_object_t object, u_short bits)
321 VM_OBJECT_ASSERT_WLOCKED(object);
322 object->flags &= ~bits;
326 * Sets the default memory attribute for the specified object. Pages
327 * that are allocated to this object are by default assigned this memory
330 * Presently, this function must be called before any pages are allocated
331 * to the object. In the future, this requirement may be relaxed for
332 * "default" and "swap" objects.
335 vm_object_set_memattr(vm_object_t object, vm_memattr_t memattr)
338 VM_OBJECT_ASSERT_WLOCKED(object);
340 if (object->type == OBJT_DEAD)
341 return (KERN_INVALID_ARGUMENT);
342 if (!TAILQ_EMPTY(&object->memq))
343 return (KERN_FAILURE);
345 object->memattr = memattr;
346 return (KERN_SUCCESS);
350 vm_object_pip_add(vm_object_t object, short i)
354 blockcount_acquire(&object->paging_in_progress, i);
358 vm_object_pip_wakeup(vm_object_t object)
361 vm_object_pip_wakeupn(object, 1);
365 vm_object_pip_wakeupn(vm_object_t object, short i)
369 blockcount_release(&object->paging_in_progress, i);
373 * Atomically drop the object lock and wait for pip to drain. This protects
374 * from sleep/wakeup races due to identity changes. The lock is not re-acquired
378 vm_object_pip_sleep(vm_object_t object, const char *waitid)
381 (void)blockcount_sleep(&object->paging_in_progress, &object->lock,
382 waitid, PVM | PDROP);
386 vm_object_pip_wait(vm_object_t object, const char *waitid)
389 VM_OBJECT_ASSERT_WLOCKED(object);
391 blockcount_wait(&object->paging_in_progress, &object->lock, waitid,
396 vm_object_pip_wait_unlocked(vm_object_t object, const char *waitid)
399 VM_OBJECT_ASSERT_UNLOCKED(object);
401 blockcount_wait(&object->paging_in_progress, NULL, waitid, PVM);
405 * vm_object_allocate:
407 * Returns a new object with the given size.
410 vm_object_allocate(objtype_t type, vm_pindex_t size)
417 panic("vm_object_allocate: can't create OBJT_DEAD");
419 flags = OBJ_COLORED | OBJ_SWAP;
423 flags = OBJ_FICTITIOUS | OBJ_UNMANAGED;
426 flags = OBJ_FICTITIOUS;
429 flags = OBJ_UNMANAGED;
435 panic("vm_object_allocate: type %d is undefined or dynamic",
438 object = (vm_object_t)uma_zalloc(obj_zone, M_WAITOK);
439 _vm_object_allocate(type, size, flags, object, NULL);
445 vm_object_allocate_dyn(objtype_t dyntype, vm_pindex_t size, u_short flags)
449 MPASS(dyntype >= OBJT_FIRST_DYN /* && dyntype < nitems(pagertab) */);
450 object = (vm_object_t)uma_zalloc(obj_zone, M_WAITOK);
451 _vm_object_allocate(dyntype, size, flags, object, NULL);
457 * vm_object_allocate_anon:
459 * Returns a new default object of the given size and marked as
460 * anonymous memory for special split/collapse handling. Color
461 * to be initialized by the caller.
464 vm_object_allocate_anon(vm_pindex_t size, vm_object_t backing_object,
465 struct ucred *cred, vm_size_t charge)
467 vm_object_t handle, object;
469 if (backing_object == NULL)
471 else if ((backing_object->flags & OBJ_ANON) != 0)
472 handle = backing_object->handle;
474 handle = backing_object;
475 object = uma_zalloc(obj_zone, M_WAITOK);
476 _vm_object_allocate(OBJT_SWAP, size,
477 OBJ_ANON | OBJ_ONEMAPPING | OBJ_SWAP, object, handle);
479 object->charge = cred != NULL ? charge : 0;
484 vm_object_reference_vnode(vm_object_t object)
489 * vnode objects need the lock for the first reference
490 * to serialize with vnode_object_deallocate().
492 if (!refcount_acquire_if_gt(&object->ref_count, 0)) {
493 VM_OBJECT_RLOCK(object);
494 old = refcount_acquire(&object->ref_count);
495 if (object->type == OBJT_VNODE && old == 0)
496 vref(object->handle);
497 VM_OBJECT_RUNLOCK(object);
502 * vm_object_reference:
504 * Acquires a reference to the given object.
507 vm_object_reference(vm_object_t object)
513 if (object->type == OBJT_VNODE)
514 vm_object_reference_vnode(object);
516 refcount_acquire(&object->ref_count);
517 KASSERT((object->flags & OBJ_DEAD) == 0,
518 ("vm_object_reference: Referenced dead object."));
522 * vm_object_reference_locked:
524 * Gets another reference to the given object.
526 * The object must be locked.
529 vm_object_reference_locked(vm_object_t object)
533 VM_OBJECT_ASSERT_LOCKED(object);
534 old = refcount_acquire(&object->ref_count);
535 if (object->type == OBJT_VNODE && old == 0)
536 vref(object->handle);
537 KASSERT((object->flags & OBJ_DEAD) == 0,
538 ("vm_object_reference: Referenced dead object."));
542 * Handle deallocating an object of type OBJT_VNODE.
545 vm_object_deallocate_vnode(vm_object_t object)
547 struct vnode *vp = (struct vnode *) object->handle;
550 KASSERT(object->type == OBJT_VNODE,
551 ("vm_object_deallocate_vnode: not a vnode object"));
552 KASSERT(vp != NULL, ("vm_object_deallocate_vnode: missing vp"));
554 /* Object lock to protect handle lookup. */
555 last = refcount_release(&object->ref_count);
556 VM_OBJECT_RUNLOCK(object);
561 if (!umtx_shm_vnobj_persistent)
562 umtx_shm_object_terminated(object);
564 /* vrele may need the vnode lock. */
569 * We dropped a reference on an object and discovered that it had a
570 * single remaining shadow. This is a sibling of the reference we
571 * dropped. Attempt to collapse the sibling and backing object.
574 vm_object_deallocate_anon(vm_object_t backing_object)
578 /* Fetch the final shadow. */
579 object = LIST_FIRST(&backing_object->shadow_head);
580 KASSERT(object != NULL &&
581 atomic_load_int(&backing_object->shadow_count) == 1,
582 ("vm_object_anon_deallocate: ref_count: %d, shadow_count: %d",
583 backing_object->ref_count,
584 atomic_load_int(&backing_object->shadow_count)));
585 KASSERT((object->flags & OBJ_ANON) != 0,
586 ("invalid shadow object %p", object));
588 if (!VM_OBJECT_TRYWLOCK(object)) {
590 * Prevent object from disappearing since we do not have a
593 vm_object_pip_add(object, 1);
594 VM_OBJECT_WUNLOCK(backing_object);
595 VM_OBJECT_WLOCK(object);
596 vm_object_pip_wakeup(object);
598 VM_OBJECT_WUNLOCK(backing_object);
601 * Check for a collapse/terminate race with the last reference holder.
603 if ((object->flags & (OBJ_DEAD | OBJ_COLLAPSING)) != 0 ||
604 !refcount_acquire_if_not_zero(&object->ref_count)) {
605 VM_OBJECT_WUNLOCK(object);
608 backing_object = object->backing_object;
609 if (backing_object != NULL && (backing_object->flags & OBJ_ANON) != 0)
610 vm_object_collapse(object);
611 VM_OBJECT_WUNLOCK(object);
617 * vm_object_deallocate:
619 * Release a reference to the specified object,
620 * gained either through a vm_object_allocate
621 * or a vm_object_reference call. When all references
622 * are gone, storage associated with this object
623 * may be relinquished.
625 * No object may be locked.
628 vm_object_deallocate(vm_object_t object)
633 while (object != NULL) {
635 * If the reference count goes to 0 we start calling
636 * vm_object_terminate() on the object chain. A ref count
637 * of 1 may be a special case depending on the shadow count
638 * being 0 or 1. These cases require a write lock on the
641 if ((object->flags & OBJ_ANON) == 0)
642 released = refcount_release_if_gt(&object->ref_count, 1);
644 released = refcount_release_if_gt(&object->ref_count, 2);
648 if (object->type == OBJT_VNODE) {
649 VM_OBJECT_RLOCK(object);
650 if (object->type == OBJT_VNODE) {
651 vm_object_deallocate_vnode(object);
654 VM_OBJECT_RUNLOCK(object);
657 VM_OBJECT_WLOCK(object);
658 KASSERT(object->ref_count > 0,
659 ("vm_object_deallocate: object deallocated too many times: %d",
663 * If this is not the final reference to an anonymous
664 * object we may need to collapse the shadow chain.
666 if (!refcount_release(&object->ref_count)) {
667 if (object->ref_count > 1 ||
668 atomic_load_int(&object->shadow_count) == 0) {
669 if ((object->flags & OBJ_ANON) != 0 &&
670 object->ref_count == 1)
671 vm_object_set_flag(object,
673 VM_OBJECT_WUNLOCK(object);
677 /* Handle collapsing last ref on anonymous objects. */
678 object = vm_object_deallocate_anon(object);
683 * Handle the final reference to an object. We restart
684 * the loop with the backing object to avoid recursion.
686 umtx_shm_object_terminated(object);
687 temp = object->backing_object;
689 KASSERT(object->type == OBJT_SWAP,
690 ("shadowed tmpfs v_object 2 %p", object));
691 vm_object_backing_remove(object);
694 KASSERT((object->flags & OBJ_DEAD) == 0,
695 ("vm_object_deallocate: Terminating dead object."));
696 vm_object_set_flag(object, OBJ_DEAD);
697 vm_object_terminate(object);
703 vm_object_destroy(vm_object_t object)
705 uma_zfree(obj_zone, object);
709 vm_object_sub_shadow(vm_object_t object)
711 KASSERT(object->shadow_count >= 1,
712 ("object %p sub_shadow count zero", object));
713 atomic_subtract_int(&object->shadow_count, 1);
717 vm_object_backing_remove_locked(vm_object_t object)
719 vm_object_t backing_object;
721 backing_object = object->backing_object;
722 VM_OBJECT_ASSERT_WLOCKED(object);
723 VM_OBJECT_ASSERT_WLOCKED(backing_object);
725 KASSERT((object->flags & OBJ_COLLAPSING) == 0,
726 ("vm_object_backing_remove: Removing collapsing object."));
728 vm_object_sub_shadow(backing_object);
729 if ((object->flags & OBJ_SHADOWLIST) != 0) {
730 LIST_REMOVE(object, shadow_list);
731 vm_object_clear_flag(object, OBJ_SHADOWLIST);
733 object->backing_object = NULL;
737 vm_object_backing_remove(vm_object_t object)
739 vm_object_t backing_object;
741 VM_OBJECT_ASSERT_WLOCKED(object);
743 backing_object = object->backing_object;
744 if ((object->flags & OBJ_SHADOWLIST) != 0) {
745 VM_OBJECT_WLOCK(backing_object);
746 vm_object_backing_remove_locked(object);
747 VM_OBJECT_WUNLOCK(backing_object);
749 object->backing_object = NULL;
750 vm_object_sub_shadow(backing_object);
755 vm_object_backing_insert_locked(vm_object_t object, vm_object_t backing_object)
758 VM_OBJECT_ASSERT_WLOCKED(object);
760 atomic_add_int(&backing_object->shadow_count, 1);
761 if ((backing_object->flags & OBJ_ANON) != 0) {
762 VM_OBJECT_ASSERT_WLOCKED(backing_object);
763 LIST_INSERT_HEAD(&backing_object->shadow_head, object,
765 vm_object_set_flag(object, OBJ_SHADOWLIST);
767 object->backing_object = backing_object;
771 vm_object_backing_insert(vm_object_t object, vm_object_t backing_object)
774 VM_OBJECT_ASSERT_WLOCKED(object);
776 if ((backing_object->flags & OBJ_ANON) != 0) {
777 VM_OBJECT_WLOCK(backing_object);
778 vm_object_backing_insert_locked(object, backing_object);
779 VM_OBJECT_WUNLOCK(backing_object);
781 object->backing_object = backing_object;
782 atomic_add_int(&backing_object->shadow_count, 1);
787 * Insert an object into a backing_object's shadow list with an additional
788 * reference to the backing_object added.
791 vm_object_backing_insert_ref(vm_object_t object, vm_object_t backing_object)
794 VM_OBJECT_ASSERT_WLOCKED(object);
796 if ((backing_object->flags & OBJ_ANON) != 0) {
797 VM_OBJECT_WLOCK(backing_object);
798 KASSERT((backing_object->flags & OBJ_DEAD) == 0,
799 ("shadowing dead anonymous object"));
800 vm_object_reference_locked(backing_object);
801 vm_object_backing_insert_locked(object, backing_object);
802 vm_object_clear_flag(backing_object, OBJ_ONEMAPPING);
803 VM_OBJECT_WUNLOCK(backing_object);
805 vm_object_reference(backing_object);
806 atomic_add_int(&backing_object->shadow_count, 1);
807 object->backing_object = backing_object;
812 * Transfer a backing reference from backing_object to object.
815 vm_object_backing_transfer(vm_object_t object, vm_object_t backing_object)
817 vm_object_t new_backing_object;
820 * Note that the reference to backing_object->backing_object
821 * moves from within backing_object to within object.
823 vm_object_backing_remove_locked(object);
824 new_backing_object = backing_object->backing_object;
825 if (new_backing_object == NULL)
827 if ((new_backing_object->flags & OBJ_ANON) != 0) {
828 VM_OBJECT_WLOCK(new_backing_object);
829 vm_object_backing_remove_locked(backing_object);
830 vm_object_backing_insert_locked(object, new_backing_object);
831 VM_OBJECT_WUNLOCK(new_backing_object);
834 * shadow_count for new_backing_object is left
835 * unchanged, its reference provided by backing_object
836 * is replaced by object.
838 object->backing_object = new_backing_object;
839 backing_object->backing_object = NULL;
844 * Wait for a concurrent collapse to settle.
847 vm_object_collapse_wait(vm_object_t object)
850 VM_OBJECT_ASSERT_WLOCKED(object);
852 while ((object->flags & OBJ_COLLAPSING) != 0) {
853 vm_object_pip_wait(object, "vmcolwait");
854 counter_u64_add(object_collapse_waits, 1);
859 * Waits for a backing object to clear a pending collapse and returns
860 * it locked if it is an ANON object.
863 vm_object_backing_collapse_wait(vm_object_t object)
865 vm_object_t backing_object;
867 VM_OBJECT_ASSERT_WLOCKED(object);
870 backing_object = object->backing_object;
871 if (backing_object == NULL ||
872 (backing_object->flags & OBJ_ANON) == 0)
874 VM_OBJECT_WLOCK(backing_object);
875 if ((backing_object->flags & (OBJ_DEAD | OBJ_COLLAPSING)) == 0)
877 VM_OBJECT_WUNLOCK(object);
878 vm_object_pip_sleep(backing_object, "vmbckwait");
879 counter_u64_add(object_collapse_waits, 1);
880 VM_OBJECT_WLOCK(object);
882 return (backing_object);
886 * vm_object_terminate_pages removes any remaining pageable pages
887 * from the object and resets the object to an empty state.
890 vm_object_terminate_pages(vm_object_t object)
894 VM_OBJECT_ASSERT_WLOCKED(object);
897 * Free any remaining pageable pages. This also removes them from the
898 * paging queues. However, don't free wired pages, just remove them
899 * from the object. Rather than incrementally removing each page from
900 * the object, the page and object are reset to any empty state.
902 TAILQ_FOREACH_SAFE(p, &object->memq, listq, p_next) {
903 vm_page_assert_unbusied(p);
904 KASSERT(p->object == object &&
905 (p->ref_count & VPRC_OBJREF) != 0,
906 ("vm_object_terminate_pages: page %p is inconsistent", p));
909 if (vm_page_drop(p, VPRC_OBJREF) == VPRC_OBJREF) {
916 * If the object contained any pages, then reset it to an empty state.
917 * None of the object's fields, including "resident_page_count", were
918 * modified by the preceding loop.
920 if (object->resident_page_count != 0) {
921 vm_radix_reclaim_allnodes(&object->rtree);
922 TAILQ_INIT(&object->memq);
923 object->resident_page_count = 0;
924 if (object->type == OBJT_VNODE)
925 vdrop(object->handle);
930 * vm_object_terminate actually destroys the specified object, freeing
931 * up all previously used resources.
933 * The object must be locked.
934 * This routine may block.
937 vm_object_terminate(vm_object_t object)
940 VM_OBJECT_ASSERT_WLOCKED(object);
941 KASSERT((object->flags & OBJ_DEAD) != 0,
942 ("terminating non-dead obj %p", object));
943 KASSERT((object->flags & OBJ_COLLAPSING) == 0,
944 ("terminating collapsing obj %p", object));
945 KASSERT(object->backing_object == NULL,
946 ("terminating shadow obj %p", object));
949 * Wait for the pageout daemon and other current users to be
950 * done with the object. Note that new paging_in_progress
951 * users can come after this wait, but they must check
952 * OBJ_DEAD flag set (without unlocking the object), and avoid
953 * the object being terminated.
955 vm_object_pip_wait(object, "objtrm");
957 KASSERT(object->ref_count == 0,
958 ("vm_object_terminate: object with references, ref_count=%d",
961 if ((object->flags & OBJ_PG_DTOR) == 0)
962 vm_object_terminate_pages(object);
964 #if VM_NRESERVLEVEL > 0
965 if (__predict_false(!LIST_EMPTY(&object->rvq)))
966 vm_reserv_break_all(object);
969 KASSERT(object->cred == NULL || (object->flags & OBJ_SWAP) != 0,
970 ("%s: non-swap obj %p has cred", __func__, object));
973 * Let the pager know object is dead.
975 vm_pager_deallocate(object);
976 VM_OBJECT_WUNLOCK(object);
978 vm_object_destroy(object);
982 * Make the page read-only so that we can clear the object flags. However, if
983 * this is a nosync mmap then the object is likely to stay dirty so do not
984 * mess with the page and do not clear the object flags. Returns TRUE if the
985 * page should be flushed, and FALSE otherwise.
988 vm_object_page_remove_write(vm_page_t p, int flags, boolean_t *allclean)
991 vm_page_assert_busied(p);
994 * If we have been asked to skip nosync pages and this is a
995 * nosync page, skip it. Note that the object flags were not
996 * cleared in this case so we do not have to set them.
998 if ((flags & OBJPC_NOSYNC) != 0 && (p->a.flags & PGA_NOSYNC) != 0) {
1002 pmap_remove_write(p);
1003 return (p->dirty != 0);
1008 * vm_object_page_clean
1010 * Clean all dirty pages in the specified range of object. Leaves page
1011 * on whatever queue it is currently on. If NOSYNC is set then do not
1012 * write out pages with PGA_NOSYNC set (originally comes from MAP_NOSYNC),
1013 * leaving the object dirty.
1015 * For swap objects backing tmpfs regular files, do not flush anything,
1016 * but remove write protection on the mapped pages to update mtime through
1019 * When stuffing pages asynchronously, allow clustering. XXX we need a
1020 * synchronous clustering mode implementation.
1022 * Odd semantics: if start == end, we clean everything.
1024 * The object must be locked.
1026 * Returns FALSE if some page from the range was not written, as
1027 * reported by the pager, and TRUE otherwise.
1030 vm_object_page_clean(vm_object_t object, vm_ooffset_t start, vm_ooffset_t end,
1034 vm_pindex_t pi, tend, tstart;
1035 int curgeneration, n, pagerflags;
1036 boolean_t eio, res, allclean;
1038 VM_OBJECT_ASSERT_WLOCKED(object);
1040 if (!vm_object_mightbedirty(object) || object->resident_page_count == 0)
1043 pagerflags = (flags & (OBJPC_SYNC | OBJPC_INVAL)) != 0 ?
1044 VM_PAGER_PUT_SYNC : VM_PAGER_CLUSTER_OK;
1045 pagerflags |= (flags & OBJPC_INVAL) != 0 ? VM_PAGER_PUT_INVAL : 0;
1047 tstart = OFF_TO_IDX(start);
1048 tend = (end == 0) ? object->size : OFF_TO_IDX(end + PAGE_MASK);
1049 allclean = tstart == 0 && tend >= object->size;
1053 curgeneration = object->generation;
1055 for (p = vm_page_find_least(object, tstart); p != NULL; p = np) {
1059 np = TAILQ_NEXT(p, listq);
1060 if (vm_page_none_valid(p))
1062 if (vm_page_busy_acquire(p, VM_ALLOC_WAITFAIL) == 0) {
1063 if (object->generation != curgeneration &&
1064 (flags & OBJPC_SYNC) != 0)
1066 np = vm_page_find_least(object, pi);
1069 if (!vm_object_page_remove_write(p, flags, &allclean)) {
1073 if (object->type == OBJT_VNODE) {
1074 n = vm_object_page_collect_flush(object, p, pagerflags,
1075 flags, &allclean, &eio);
1080 if (object->generation != curgeneration &&
1081 (flags & OBJPC_SYNC) != 0)
1085 * If the VOP_PUTPAGES() did a truncated write, so
1086 * that even the first page of the run is not fully
1087 * written, vm_pageout_flush() returns 0 as the run
1088 * length. Since the condition that caused truncated
1089 * write may be permanent, e.g. exhausted free space,
1090 * accepting n == 0 would cause an infinite loop.
1092 * Forwarding the iterator leaves the unwritten page
1093 * behind, but there is not much we can do there if
1094 * filesystem refuses to write it.
1104 np = vm_page_find_least(object, pi + n);
1107 VOP_FSYNC(vp, (pagerflags & VM_PAGER_PUT_SYNC) ? MNT_WAIT : 0);
1111 * Leave updating cleangeneration for tmpfs objects to tmpfs
1112 * scan. It needs to update mtime, which happens for other
1113 * filesystems during page writeouts.
1115 if (allclean && object->type == OBJT_VNODE)
1116 object->cleangeneration = curgeneration;
1121 vm_object_page_collect_flush(vm_object_t object, vm_page_t p, int pagerflags,
1122 int flags, boolean_t *allclean, boolean_t *eio)
1124 vm_page_t ma[vm_pageout_page_count], p_first, tp;
1125 int count, i, mreq, runlen;
1127 vm_page_lock_assert(p, MA_NOTOWNED);
1128 vm_page_assert_xbusied(p);
1129 VM_OBJECT_ASSERT_WLOCKED(object);
1134 for (tp = p; count < vm_pageout_page_count; count++) {
1135 tp = vm_page_next(tp);
1136 if (tp == NULL || vm_page_tryxbusy(tp) == 0)
1138 if (!vm_object_page_remove_write(tp, flags, allclean)) {
1139 vm_page_xunbusy(tp);
1144 for (p_first = p; count < vm_pageout_page_count; count++) {
1145 tp = vm_page_prev(p_first);
1146 if (tp == NULL || vm_page_tryxbusy(tp) == 0)
1148 if (!vm_object_page_remove_write(tp, flags, allclean)) {
1149 vm_page_xunbusy(tp);
1156 for (tp = p_first, i = 0; i < count; tp = TAILQ_NEXT(tp, listq), i++)
1159 vm_pageout_flush(ma, count, pagerflags, mreq, &runlen, eio);
1164 * Note that there is absolutely no sense in writing out
1165 * anonymous objects, so we track down the vnode object
1167 * We invalidate (remove) all pages from the address space
1168 * for semantic correctness.
1170 * If the backing object is a device object with unmanaged pages, then any
1171 * mappings to the specified range of pages must be removed before this
1172 * function is called.
1174 * Note: certain anonymous maps, such as MAP_NOSYNC maps,
1175 * may start out with a NULL object.
1178 vm_object_sync(vm_object_t object, vm_ooffset_t offset, vm_size_t size,
1179 boolean_t syncio, boolean_t invalidate)
1181 vm_object_t backing_object;
1184 int error, flags, fsync_after;
1191 VM_OBJECT_WLOCK(object);
1192 while ((backing_object = object->backing_object) != NULL) {
1193 VM_OBJECT_WLOCK(backing_object);
1194 offset += object->backing_object_offset;
1195 VM_OBJECT_WUNLOCK(object);
1196 object = backing_object;
1197 if (object->size < OFF_TO_IDX(offset + size))
1198 size = IDX_TO_OFF(object->size) - offset;
1201 * Flush pages if writing is allowed, invalidate them
1202 * if invalidation requested. Pages undergoing I/O
1203 * will be ignored by vm_object_page_remove().
1205 * We cannot lock the vnode and then wait for paging
1206 * to complete without deadlocking against vm_fault.
1207 * Instead we simply call vm_object_page_remove() and
1208 * allow it to block internally on a page-by-page
1209 * basis when it encounters pages undergoing async
1212 if (object->type == OBJT_VNODE &&
1213 vm_object_mightbedirty(object) != 0 &&
1214 ((vp = object->handle)->v_vflag & VV_NOSYNC) == 0) {
1215 VM_OBJECT_WUNLOCK(object);
1216 (void)vn_start_write(vp, &mp, V_WAIT);
1217 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
1218 if (syncio && !invalidate && offset == 0 &&
1219 atop(size) == object->size) {
1221 * If syncing the whole mapping of the file,
1222 * it is faster to schedule all the writes in
1223 * async mode, also allowing the clustering,
1224 * and then wait for i/o to complete.
1229 flags = (syncio || invalidate) ? OBJPC_SYNC : 0;
1230 flags |= invalidate ? (OBJPC_SYNC | OBJPC_INVAL) : 0;
1231 fsync_after = FALSE;
1233 VM_OBJECT_WLOCK(object);
1234 res = vm_object_page_clean(object, offset, offset + size,
1236 VM_OBJECT_WUNLOCK(object);
1239 error = VOP_FSYNC(vp, MNT_WAIT, curthread);
1240 if (error != ERELOOKUP)
1244 * Allow SU/bufdaemon to handle more
1245 * dependencies in the meantime.
1248 vn_finished_write(mp);
1250 (void)vn_start_write(vp, &mp, V_WAIT);
1251 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
1255 vn_finished_write(mp);
1258 VM_OBJECT_WLOCK(object);
1260 if ((object->type == OBJT_VNODE ||
1261 object->type == OBJT_DEVICE) && invalidate) {
1262 if (object->type == OBJT_DEVICE)
1264 * The option OBJPR_NOTMAPPED must be passed here
1265 * because vm_object_page_remove() cannot remove
1266 * unmanaged mappings.
1268 flags = OBJPR_NOTMAPPED;
1272 flags = OBJPR_CLEANONLY;
1273 vm_object_page_remove(object, OFF_TO_IDX(offset),
1274 OFF_TO_IDX(offset + size + PAGE_MASK), flags);
1276 VM_OBJECT_WUNLOCK(object);
1281 * Determine whether the given advice can be applied to the object. Advice is
1282 * not applied to unmanaged pages since they never belong to page queues, and
1283 * since MADV_FREE is destructive, it can apply only to anonymous pages that
1284 * have been mapped at most once.
1287 vm_object_advice_applies(vm_object_t object, int advice)
1290 if ((object->flags & OBJ_UNMANAGED) != 0)
1292 if (advice != MADV_FREE)
1294 return ((object->flags & (OBJ_ONEMAPPING | OBJ_ANON)) ==
1295 (OBJ_ONEMAPPING | OBJ_ANON));
1299 vm_object_madvise_freespace(vm_object_t object, int advice, vm_pindex_t pindex,
1303 if (advice == MADV_FREE)
1304 vm_pager_freespace(object, pindex, size);
1308 * vm_object_madvise:
1310 * Implements the madvise function at the object/page level.
1312 * MADV_WILLNEED (any object)
1314 * Activate the specified pages if they are resident.
1316 * MADV_DONTNEED (any object)
1318 * Deactivate the specified pages if they are resident.
1320 * MADV_FREE (OBJT_SWAP objects, OBJ_ONEMAPPING only)
1322 * Deactivate and clean the specified pages if they are
1323 * resident. This permits the process to reuse the pages
1324 * without faulting or the kernel to reclaim the pages
1328 vm_object_madvise(vm_object_t object, vm_pindex_t pindex, vm_pindex_t end,
1331 vm_pindex_t tpindex;
1332 vm_object_t backing_object, tobject;
1339 VM_OBJECT_WLOCK(object);
1340 if (!vm_object_advice_applies(object, advice)) {
1341 VM_OBJECT_WUNLOCK(object);
1344 for (m = vm_page_find_least(object, pindex); pindex < end; pindex++) {
1348 * If the next page isn't resident in the top-level object, we
1349 * need to search the shadow chain. When applying MADV_FREE, we
1350 * take care to release any swap space used to store
1351 * non-resident pages.
1353 if (m == NULL || pindex < m->pindex) {
1355 * Optimize a common case: if the top-level object has
1356 * no backing object, we can skip over the non-resident
1357 * range in constant time.
1359 if (object->backing_object == NULL) {
1360 tpindex = (m != NULL && m->pindex < end) ?
1362 vm_object_madvise_freespace(object, advice,
1363 pindex, tpindex - pindex);
1364 if ((pindex = tpindex) == end)
1371 vm_object_madvise_freespace(tobject, advice,
1374 * Prepare to search the next object in the
1377 backing_object = tobject->backing_object;
1378 if (backing_object == NULL)
1380 VM_OBJECT_WLOCK(backing_object);
1382 OFF_TO_IDX(tobject->backing_object_offset);
1383 if (tobject != object)
1384 VM_OBJECT_WUNLOCK(tobject);
1385 tobject = backing_object;
1386 if (!vm_object_advice_applies(tobject, advice))
1388 } while ((tm = vm_page_lookup(tobject, tpindex)) ==
1393 m = TAILQ_NEXT(m, listq);
1397 * If the page is not in a normal state, skip it. The page
1398 * can not be invalidated while the object lock is held.
1400 if (!vm_page_all_valid(tm) || vm_page_wired(tm))
1402 KASSERT((tm->flags & PG_FICTITIOUS) == 0,
1403 ("vm_object_madvise: page %p is fictitious", tm));
1404 KASSERT((tm->oflags & VPO_UNMANAGED) == 0,
1405 ("vm_object_madvise: page %p is not managed", tm));
1406 if (vm_page_tryxbusy(tm) == 0) {
1407 if (object != tobject)
1408 VM_OBJECT_WUNLOCK(object);
1409 if (advice == MADV_WILLNEED) {
1411 * Reference the page before unlocking and
1412 * sleeping so that the page daemon is less
1413 * likely to reclaim it.
1415 vm_page_aflag_set(tm, PGA_REFERENCED);
1417 if (!vm_page_busy_sleep(tm, "madvpo", 0))
1418 VM_OBJECT_WUNLOCK(tobject);
1421 vm_page_advise(tm, advice);
1422 vm_page_xunbusy(tm);
1423 vm_object_madvise_freespace(tobject, advice, tm->pindex, 1);
1425 if (tobject != object)
1426 VM_OBJECT_WUNLOCK(tobject);
1428 VM_OBJECT_WUNLOCK(object);
1434 * Create a new object which is backed by the
1435 * specified existing object range. The source
1436 * object reference is deallocated.
1438 * The new object and offset into that object
1439 * are returned in the source parameters.
1442 vm_object_shadow(vm_object_t *object, vm_ooffset_t *offset, vm_size_t length,
1443 struct ucred *cred, bool shared)
1451 * Don't create the new object if the old object isn't shared.
1453 * If we hold the only reference we can guarantee that it won't
1454 * increase while we have the map locked. Otherwise the race is
1455 * harmless and we will end up with an extra shadow object that
1456 * will be collapsed later.
1458 if (source != NULL && source->ref_count == 1 &&
1459 (source->flags & OBJ_ANON) != 0)
1463 * Allocate a new object with the given length.
1465 result = vm_object_allocate_anon(atop(length), source, cred, length);
1468 * Store the offset into the source object, and fix up the offset into
1471 result->backing_object_offset = *offset;
1473 if (shared || source != NULL) {
1474 VM_OBJECT_WLOCK(result);
1477 * The new object shadows the source object, adding a
1478 * reference to it. Our caller changes his reference
1479 * to point to the new object, removing a reference to
1480 * the source object. Net result: no change of
1481 * reference count, unless the caller needs to add one
1482 * more reference due to forking a shared map entry.
1485 vm_object_reference_locked(result);
1486 vm_object_clear_flag(result, OBJ_ONEMAPPING);
1490 * Try to optimize the result object's page color when
1491 * shadowing in order to maintain page coloring
1492 * consistency in the combined shadowed object.
1494 if (source != NULL) {
1495 vm_object_backing_insert(result, source);
1496 result->domain = source->domain;
1497 #if VM_NRESERVLEVEL > 0
1498 vm_object_set_flag(result,
1499 (source->flags & OBJ_COLORED));
1500 result->pg_color = (source->pg_color +
1501 OFF_TO_IDX(*offset)) & ((1 << (VM_NFREEORDER -
1505 VM_OBJECT_WUNLOCK(result);
1509 * Return the new things
1518 * Split the pages in a map entry into a new object. This affords
1519 * easier removal of unused pages, and keeps object inheritance from
1520 * being a negative impact on memory usage.
1523 vm_object_split(vm_map_entry_t entry)
1525 vm_page_t m, m_next;
1526 vm_object_t orig_object, new_object, backing_object;
1527 vm_pindex_t idx, offidxstart;
1530 orig_object = entry->object.vm_object;
1531 KASSERT((orig_object->flags & OBJ_ONEMAPPING) != 0,
1532 ("vm_object_split: Splitting object with multiple mappings."));
1533 if ((orig_object->flags & OBJ_ANON) == 0)
1535 if (orig_object->ref_count <= 1)
1537 VM_OBJECT_WUNLOCK(orig_object);
1539 offidxstart = OFF_TO_IDX(entry->offset);
1540 size = atop(entry->end - entry->start);
1542 new_object = vm_object_allocate_anon(size, orig_object,
1543 orig_object->cred, ptoa(size));
1546 * We must wait for the orig_object to complete any in-progress
1547 * collapse so that the swap blocks are stable below. The
1548 * additional reference on backing_object by new object will
1549 * prevent further collapse operations until split completes.
1551 VM_OBJECT_WLOCK(orig_object);
1552 vm_object_collapse_wait(orig_object);
1555 * At this point, the new object is still private, so the order in
1556 * which the original and new objects are locked does not matter.
1558 VM_OBJECT_WLOCK(new_object);
1559 new_object->domain = orig_object->domain;
1560 backing_object = orig_object->backing_object;
1561 if (backing_object != NULL) {
1562 vm_object_backing_insert_ref(new_object, backing_object);
1563 new_object->backing_object_offset =
1564 orig_object->backing_object_offset + entry->offset;
1566 if (orig_object->cred != NULL) {
1567 crhold(orig_object->cred);
1568 KASSERT(orig_object->charge >= ptoa(size),
1569 ("orig_object->charge < 0"));
1570 orig_object->charge -= ptoa(size);
1574 * Mark the split operation so that swap_pager_getpages() knows
1575 * that the object is in transition.
1577 vm_object_set_flag(orig_object, OBJ_SPLIT);
1582 m = vm_page_find_least(orig_object, offidxstart);
1583 KASSERT(m == NULL || idx <= m->pindex - offidxstart,
1584 ("%s: object %p was repopulated", __func__, orig_object));
1585 for (; m != NULL && (idx = m->pindex - offidxstart) < size;
1587 m_next = TAILQ_NEXT(m, listq);
1590 * We must wait for pending I/O to complete before we can
1593 * We do not have to VM_PROT_NONE the page as mappings should
1594 * not be changed by this operation.
1596 if (vm_page_tryxbusy(m) == 0) {
1597 VM_OBJECT_WUNLOCK(new_object);
1598 if (vm_page_busy_sleep(m, "spltwt", 0))
1599 VM_OBJECT_WLOCK(orig_object);
1600 VM_OBJECT_WLOCK(new_object);
1605 * The page was left invalid. Likely placed there by
1606 * an incomplete fault. Just remove and ignore.
1608 if (vm_page_none_valid(m)) {
1609 if (vm_page_remove(m))
1614 /* vm_page_rename() will dirty the page. */
1615 if (vm_page_rename(m, new_object, idx)) {
1617 VM_OBJECT_WUNLOCK(new_object);
1618 VM_OBJECT_WUNLOCK(orig_object);
1620 VM_OBJECT_WLOCK(orig_object);
1621 VM_OBJECT_WLOCK(new_object);
1625 #if VM_NRESERVLEVEL > 0
1627 * If some of the reservation's allocated pages remain with
1628 * the original object, then transferring the reservation to
1629 * the new object is neither particularly beneficial nor
1630 * particularly harmful as compared to leaving the reservation
1631 * with the original object. If, however, all of the
1632 * reservation's allocated pages are transferred to the new
1633 * object, then transferring the reservation is typically
1634 * beneficial. Determining which of these two cases applies
1635 * would be more costly than unconditionally renaming the
1638 vm_reserv_rename(m, new_object, orig_object, offidxstart);
1643 * swap_pager_copy() can sleep, in which case the orig_object's
1644 * and new_object's locks are released and reacquired.
1646 swap_pager_copy(orig_object, new_object, offidxstart, 0);
1648 TAILQ_FOREACH(m, &new_object->memq, listq)
1651 vm_object_clear_flag(orig_object, OBJ_SPLIT);
1652 VM_OBJECT_WUNLOCK(orig_object);
1653 VM_OBJECT_WUNLOCK(new_object);
1654 entry->object.vm_object = new_object;
1655 entry->offset = 0LL;
1656 vm_object_deallocate(orig_object);
1657 VM_OBJECT_WLOCK(new_object);
1661 vm_object_collapse_scan_wait(vm_object_t object, vm_page_t p)
1663 vm_object_t backing_object;
1665 VM_OBJECT_ASSERT_WLOCKED(object);
1666 backing_object = object->backing_object;
1667 VM_OBJECT_ASSERT_WLOCKED(backing_object);
1669 KASSERT(p == NULL || p->object == object || p->object == backing_object,
1670 ("invalid ownership %p %p %p", p, object, backing_object));
1671 /* The page is only NULL when rename fails. */
1673 VM_OBJECT_WUNLOCK(object);
1674 VM_OBJECT_WUNLOCK(backing_object);
1676 VM_OBJECT_WLOCK(object);
1677 } else if (p->object == object) {
1678 VM_OBJECT_WUNLOCK(backing_object);
1679 if (vm_page_busy_sleep(p, "vmocol", 0))
1680 VM_OBJECT_WLOCK(object);
1682 VM_OBJECT_WUNLOCK(object);
1683 if (!vm_page_busy_sleep(p, "vmocol", 0))
1684 VM_OBJECT_WUNLOCK(backing_object);
1685 VM_OBJECT_WLOCK(object);
1687 VM_OBJECT_WLOCK(backing_object);
1688 return (TAILQ_FIRST(&backing_object->memq));
1692 vm_object_scan_all_shadowed(vm_object_t object)
1694 vm_object_t backing_object;
1696 vm_pindex_t backing_offset_index, new_pindex, pi, ps;
1698 VM_OBJECT_ASSERT_WLOCKED(object);
1699 VM_OBJECT_ASSERT_WLOCKED(object->backing_object);
1701 backing_object = object->backing_object;
1703 if ((backing_object->flags & OBJ_ANON) == 0)
1706 pi = backing_offset_index = OFF_TO_IDX(object->backing_object_offset);
1707 p = vm_page_find_least(backing_object, pi);
1708 ps = swap_pager_find_least(backing_object, pi);
1711 * Only check pages inside the parent object's range and
1712 * inside the parent object's mapping of the backing object.
1715 if (p != NULL && p->pindex < pi)
1716 p = TAILQ_NEXT(p, listq);
1718 ps = swap_pager_find_least(backing_object, pi);
1719 if (p == NULL && ps >= backing_object->size)
1724 pi = MIN(p->pindex, ps);
1726 new_pindex = pi - backing_offset_index;
1727 if (new_pindex >= object->size)
1732 * If the backing object page is busy a
1733 * grandparent or older page may still be
1734 * undergoing CoW. It is not safe to collapse
1735 * the backing object until it is quiesced.
1737 if (vm_page_tryxbusy(p) == 0)
1741 * We raced with the fault handler that left
1742 * newly allocated invalid page on the object
1743 * queue and retried.
1745 if (!vm_page_all_valid(p))
1750 * See if the parent has the page or if the parent's object
1751 * pager has the page. If the parent has the page but the page
1752 * is not valid, the parent's object pager must have the page.
1754 * If this fails, the parent does not completely shadow the
1755 * object and we might as well give up now.
1757 pp = vm_page_lookup(object, new_pindex);
1760 * The valid check here is stable due to object lock
1761 * being required to clear valid and initiate paging.
1762 * Busy of p disallows fault handler to validate pp.
1764 if ((pp == NULL || vm_page_none_valid(pp)) &&
1765 !vm_pager_has_page(object, new_pindex, NULL, NULL))
1779 vm_object_collapse_scan(vm_object_t object)
1781 vm_object_t backing_object;
1782 vm_page_t next, p, pp;
1783 vm_pindex_t backing_offset_index, new_pindex;
1785 VM_OBJECT_ASSERT_WLOCKED(object);
1786 VM_OBJECT_ASSERT_WLOCKED(object->backing_object);
1788 backing_object = object->backing_object;
1789 backing_offset_index = OFF_TO_IDX(object->backing_object_offset);
1794 for (p = TAILQ_FIRST(&backing_object->memq); p != NULL; p = next) {
1795 next = TAILQ_NEXT(p, listq);
1796 new_pindex = p->pindex - backing_offset_index;
1799 * Check for busy page
1801 if (vm_page_tryxbusy(p) == 0) {
1802 next = vm_object_collapse_scan_wait(object, p);
1806 KASSERT(object->backing_object == backing_object,
1807 ("vm_object_collapse_scan: backing object mismatch %p != %p",
1808 object->backing_object, backing_object));
1809 KASSERT(p->object == backing_object,
1810 ("vm_object_collapse_scan: object mismatch %p != %p",
1811 p->object, backing_object));
1813 if (p->pindex < backing_offset_index ||
1814 new_pindex >= object->size) {
1815 vm_pager_freespace(backing_object, p->pindex, 1);
1817 KASSERT(!pmap_page_is_mapped(p),
1818 ("freeing mapped page %p", p));
1819 if (vm_page_remove(p))
1824 if (!vm_page_all_valid(p)) {
1825 KASSERT(!pmap_page_is_mapped(p),
1826 ("freeing mapped page %p", p));
1827 if (vm_page_remove(p))
1832 pp = vm_page_lookup(object, new_pindex);
1833 if (pp != NULL && vm_page_tryxbusy(pp) == 0) {
1836 * The page in the parent is busy and possibly not
1837 * (yet) valid. Until its state is finalized by the
1838 * busy bit owner, we can't tell whether it shadows the
1841 next = vm_object_collapse_scan_wait(object, pp);
1845 if (pp != NULL && vm_page_none_valid(pp)) {
1847 * The page was invalid in the parent. Likely placed
1848 * there by an incomplete fault. Just remove and
1849 * ignore. p can replace it.
1851 if (vm_page_remove(pp))
1856 if (pp != NULL || vm_pager_has_page(object, new_pindex, NULL,
1859 * The page already exists in the parent OR swap exists
1860 * for this location in the parent. Leave the parent's
1861 * page alone. Destroy the original page from the
1864 vm_pager_freespace(backing_object, p->pindex, 1);
1865 KASSERT(!pmap_page_is_mapped(p),
1866 ("freeing mapped page %p", p));
1867 if (vm_page_remove(p))
1870 vm_page_xunbusy(pp);
1875 * Page does not exist in parent, rename the page from the
1876 * backing object to the main object.
1878 * If the page was mapped to a process, it can remain mapped
1879 * through the rename. vm_page_rename() will dirty the page.
1881 if (vm_page_rename(p, object, new_pindex)) {
1883 next = vm_object_collapse_scan_wait(object, NULL);
1887 /* Use the old pindex to free the right page. */
1888 vm_pager_freespace(backing_object, new_pindex +
1889 backing_offset_index, 1);
1891 #if VM_NRESERVLEVEL > 0
1893 * Rename the reservation.
1895 vm_reserv_rename(p, object, backing_object,
1896 backing_offset_index);
1904 * vm_object_collapse:
1906 * Collapse an object with the object backing it.
1907 * Pages in the backing object are moved into the
1908 * parent, and the backing object is deallocated.
1911 vm_object_collapse(vm_object_t object)
1913 vm_object_t backing_object, new_backing_object;
1915 VM_OBJECT_ASSERT_WLOCKED(object);
1918 KASSERT((object->flags & (OBJ_DEAD | OBJ_ANON)) == OBJ_ANON,
1919 ("collapsing invalid object"));
1922 * Wait for the backing_object to finish any pending
1923 * collapse so that the caller sees the shortest possible
1926 backing_object = vm_object_backing_collapse_wait(object);
1927 if (backing_object == NULL)
1930 KASSERT(object->ref_count > 0 &&
1931 object->ref_count > atomic_load_int(&object->shadow_count),
1932 ("collapse with invalid ref %d or shadow %d count.",
1933 object->ref_count, atomic_load_int(&object->shadow_count)));
1934 KASSERT((backing_object->flags &
1935 (OBJ_COLLAPSING | OBJ_DEAD)) == 0,
1936 ("vm_object_collapse: Backing object already collapsing."));
1937 KASSERT((object->flags & (OBJ_COLLAPSING | OBJ_DEAD)) == 0,
1938 ("vm_object_collapse: object is already collapsing."));
1941 * We know that we can either collapse the backing object if
1942 * the parent is the only reference to it, or (perhaps) have
1943 * the parent bypass the object if the parent happens to shadow
1944 * all the resident pages in the entire backing object.
1946 if (backing_object->ref_count == 1) {
1947 KASSERT(atomic_load_int(&backing_object->shadow_count)
1949 ("vm_object_collapse: shadow_count: %d",
1950 atomic_load_int(&backing_object->shadow_count)));
1951 vm_object_pip_add(object, 1);
1952 vm_object_set_flag(object, OBJ_COLLAPSING);
1953 vm_object_pip_add(backing_object, 1);
1954 vm_object_set_flag(backing_object, OBJ_DEAD);
1957 * If there is exactly one reference to the backing
1958 * object, we can collapse it into the parent.
1960 vm_object_collapse_scan(object);
1962 #if VM_NRESERVLEVEL > 0
1964 * Break any reservations from backing_object.
1966 if (__predict_false(!LIST_EMPTY(&backing_object->rvq)))
1967 vm_reserv_break_all(backing_object);
1971 * Move the pager from backing_object to object.
1973 * swap_pager_copy() can sleep, in which case the
1974 * backing_object's and object's locks are released and
1977 swap_pager_copy(backing_object, object,
1978 OFF_TO_IDX(object->backing_object_offset), TRUE);
1981 * Object now shadows whatever backing_object did.
1983 vm_object_clear_flag(object, OBJ_COLLAPSING);
1984 vm_object_backing_transfer(object, backing_object);
1985 object->backing_object_offset +=
1986 backing_object->backing_object_offset;
1987 VM_OBJECT_WUNLOCK(object);
1988 vm_object_pip_wakeup(object);
1991 * Discard backing_object.
1993 * Since the backing object has no pages, no pager left,
1994 * and no object references within it, all that is
1995 * necessary is to dispose of it.
1997 KASSERT(backing_object->ref_count == 1, (
1998 "backing_object %p was somehow re-referenced during collapse!",
2000 vm_object_pip_wakeup(backing_object);
2001 (void)refcount_release(&backing_object->ref_count);
2002 vm_object_terminate(backing_object);
2003 counter_u64_add(object_collapses, 1);
2004 VM_OBJECT_WLOCK(object);
2007 * If we do not entirely shadow the backing object,
2008 * there is nothing we can do so we give up.
2010 * The object lock and backing_object lock must not
2011 * be dropped during this sequence.
2013 if (!vm_object_scan_all_shadowed(object)) {
2014 VM_OBJECT_WUNLOCK(backing_object);
2019 * Make the parent shadow the next object in the
2020 * chain. Deallocating backing_object will not remove
2021 * it, since its reference count is at least 2.
2023 vm_object_backing_remove_locked(object);
2024 new_backing_object = backing_object->backing_object;
2025 if (new_backing_object != NULL) {
2026 vm_object_backing_insert_ref(object,
2027 new_backing_object);
2028 object->backing_object_offset +=
2029 backing_object->backing_object_offset;
2033 * Drop the reference count on backing_object. Since
2034 * its ref_count was at least 2, it will not vanish.
2036 (void)refcount_release(&backing_object->ref_count);
2037 KASSERT(backing_object->ref_count >= 1, (
2038 "backing_object %p was somehow dereferenced during collapse!",
2040 VM_OBJECT_WUNLOCK(backing_object);
2041 counter_u64_add(object_bypasses, 1);
2045 * Try again with this object's new backing object.
2051 * vm_object_page_remove:
2053 * For the given object, either frees or invalidates each of the
2054 * specified pages. In general, a page is freed. However, if a page is
2055 * wired for any reason other than the existence of a managed, wired
2056 * mapping, then it may be invalidated but not removed from the object.
2057 * Pages are specified by the given range ["start", "end") and the option
2058 * OBJPR_CLEANONLY. As a special case, if "end" is zero, then the range
2059 * extends from "start" to the end of the object. If the option
2060 * OBJPR_CLEANONLY is specified, then only the non-dirty pages within the
2061 * specified range are affected. If the option OBJPR_NOTMAPPED is
2062 * specified, then the pages within the specified range must have no
2063 * mappings. Otherwise, if this option is not specified, any mappings to
2064 * the specified pages are removed before the pages are freed or
2067 * In general, this operation should only be performed on objects that
2068 * contain managed pages. There are, however, two exceptions. First, it
2069 * is performed on the kernel and kmem objects by vm_map_entry_delete().
2070 * Second, it is used by msync(..., MS_INVALIDATE) to invalidate device-
2071 * backed pages. In both of these cases, the option OBJPR_CLEANONLY must
2072 * not be specified and the option OBJPR_NOTMAPPED must be specified.
2074 * The object must be locked.
2077 vm_object_page_remove(vm_object_t object, vm_pindex_t start, vm_pindex_t end,
2082 VM_OBJECT_ASSERT_WLOCKED(object);
2083 KASSERT((object->flags & OBJ_UNMANAGED) == 0 ||
2084 (options & (OBJPR_CLEANONLY | OBJPR_NOTMAPPED)) == OBJPR_NOTMAPPED,
2085 ("vm_object_page_remove: illegal options for object %p", object));
2086 if (object->resident_page_count == 0)
2088 vm_object_pip_add(object, 1);
2090 p = vm_page_find_least(object, start);
2093 * Here, the variable "p" is either (1) the page with the least pindex
2094 * greater than or equal to the parameter "start" or (2) NULL.
2096 for (; p != NULL && (p->pindex < end || end == 0); p = next) {
2097 next = TAILQ_NEXT(p, listq);
2100 * Skip invalid pages if asked to do so. Try to avoid acquiring
2101 * the busy lock, as some consumers rely on this to avoid
2104 * A thread may concurrently transition the page from invalid to
2105 * valid using only the busy lock, so the result of this check
2106 * is immediately stale. It is up to consumers to handle this,
2107 * for instance by ensuring that all invalid->valid transitions
2108 * happen with a mutex held, as may be possible for a
2111 if ((options & OBJPR_VALIDONLY) != 0 && vm_page_none_valid(p))
2115 * If the page is wired for any reason besides the existence
2116 * of managed, wired mappings, then it cannot be freed. For
2117 * example, fictitious pages, which represent device memory,
2118 * are inherently wired and cannot be freed. They can,
2119 * however, be invalidated if the option OBJPR_CLEANONLY is
2122 if (vm_page_tryxbusy(p) == 0) {
2123 if (vm_page_busy_sleep(p, "vmopar", 0))
2124 VM_OBJECT_WLOCK(object);
2127 if ((options & OBJPR_VALIDONLY) != 0 && vm_page_none_valid(p)) {
2131 if (vm_page_wired(p)) {
2133 if ((options & OBJPR_NOTMAPPED) == 0 &&
2134 object->ref_count != 0)
2136 if ((options & OBJPR_CLEANONLY) == 0) {
2143 KASSERT((p->flags & PG_FICTITIOUS) == 0,
2144 ("vm_object_page_remove: page %p is fictitious", p));
2145 if ((options & OBJPR_CLEANONLY) != 0 &&
2146 !vm_page_none_valid(p)) {
2147 if ((options & OBJPR_NOTMAPPED) == 0 &&
2148 object->ref_count != 0 &&
2149 !vm_page_try_remove_write(p))
2151 if (p->dirty != 0) {
2156 if ((options & OBJPR_NOTMAPPED) == 0 &&
2157 object->ref_count != 0 && !vm_page_try_remove_all(p))
2161 vm_object_pip_wakeup(object);
2163 vm_pager_freespace(object, start, (end == 0 ? object->size : end) -
2168 * vm_object_page_noreuse:
2170 * For the given object, attempt to move the specified pages to
2171 * the head of the inactive queue. This bypasses regular LRU
2172 * operation and allows the pages to be reused quickly under memory
2173 * pressure. If a page is wired for any reason, then it will not
2174 * be queued. Pages are specified by the range ["start", "end").
2175 * As a special case, if "end" is zero, then the range extends from
2176 * "start" to the end of the object.
2178 * This operation should only be performed on objects that
2179 * contain non-fictitious, managed pages.
2181 * The object must be locked.
2184 vm_object_page_noreuse(vm_object_t object, vm_pindex_t start, vm_pindex_t end)
2188 VM_OBJECT_ASSERT_LOCKED(object);
2189 KASSERT((object->flags & (OBJ_FICTITIOUS | OBJ_UNMANAGED)) == 0,
2190 ("vm_object_page_noreuse: illegal object %p", object));
2191 if (object->resident_page_count == 0)
2193 p = vm_page_find_least(object, start);
2196 * Here, the variable "p" is either (1) the page with the least pindex
2197 * greater than or equal to the parameter "start" or (2) NULL.
2199 for (; p != NULL && (p->pindex < end || end == 0); p = next) {
2200 next = TAILQ_NEXT(p, listq);
2201 vm_page_deactivate_noreuse(p);
2206 * Populate the specified range of the object with valid pages. Returns
2207 * TRUE if the range is successfully populated and FALSE otherwise.
2209 * Note: This function should be optimized to pass a larger array of
2210 * pages to vm_pager_get_pages() before it is applied to a non-
2211 * OBJT_DEVICE object.
2213 * The object must be locked.
2216 vm_object_populate(vm_object_t object, vm_pindex_t start, vm_pindex_t end)
2222 VM_OBJECT_ASSERT_WLOCKED(object);
2223 for (pindex = start; pindex < end; pindex++) {
2224 rv = vm_page_grab_valid(&m, object, pindex, VM_ALLOC_NORMAL);
2225 if (rv != VM_PAGER_OK)
2229 * Keep "m" busy because a subsequent iteration may unlock
2233 if (pindex > start) {
2234 m = vm_page_lookup(object, start);
2235 while (m != NULL && m->pindex < pindex) {
2237 m = TAILQ_NEXT(m, listq);
2240 return (pindex == end);
2244 * Routine: vm_object_coalesce
2245 * Function: Coalesces two objects backing up adjoining
2246 * regions of memory into a single object.
2248 * returns TRUE if objects were combined.
2250 * NOTE: Only works at the moment if the second object is NULL -
2251 * if it's not, which object do we lock first?
2254 * prev_object First object to coalesce
2255 * prev_offset Offset into prev_object
2256 * prev_size Size of reference to prev_object
2257 * next_size Size of reference to the second object
2258 * reserved Indicator that extension region has
2259 * swap accounted for
2262 * The object must *not* be locked.
2265 vm_object_coalesce(vm_object_t prev_object, vm_ooffset_t prev_offset,
2266 vm_size_t prev_size, vm_size_t next_size, boolean_t reserved)
2268 vm_pindex_t next_pindex;
2270 if (prev_object == NULL)
2272 if ((prev_object->flags & OBJ_ANON) == 0)
2275 VM_OBJECT_WLOCK(prev_object);
2277 * Try to collapse the object first.
2279 vm_object_collapse(prev_object);
2282 * Can't coalesce if: . more than one reference . paged out . shadows
2283 * another object . has a copy elsewhere (any of which mean that the
2284 * pages not mapped to prev_entry may be in use anyway)
2286 if (prev_object->backing_object != NULL) {
2287 VM_OBJECT_WUNLOCK(prev_object);
2291 prev_size >>= PAGE_SHIFT;
2292 next_size >>= PAGE_SHIFT;
2293 next_pindex = OFF_TO_IDX(prev_offset) + prev_size;
2295 if (prev_object->ref_count > 1 &&
2296 prev_object->size != next_pindex &&
2297 (prev_object->flags & OBJ_ONEMAPPING) == 0) {
2298 VM_OBJECT_WUNLOCK(prev_object);
2303 * Account for the charge.
2305 if (prev_object->cred != NULL) {
2307 * If prev_object was charged, then this mapping,
2308 * although not charged now, may become writable
2309 * later. Non-NULL cred in the object would prevent
2310 * swap reservation during enabling of the write
2311 * access, so reserve swap now. Failed reservation
2312 * cause allocation of the separate object for the map
2313 * entry, and swap reservation for this entry is
2314 * managed in appropriate time.
2316 if (!reserved && !swap_reserve_by_cred(ptoa(next_size),
2317 prev_object->cred)) {
2318 VM_OBJECT_WUNLOCK(prev_object);
2321 prev_object->charge += ptoa(next_size);
2325 * Remove any pages that may still be in the object from a previous
2328 if (next_pindex < prev_object->size) {
2329 vm_object_page_remove(prev_object, next_pindex, next_pindex +
2332 if (prev_object->cred != NULL) {
2333 KASSERT(prev_object->charge >=
2334 ptoa(prev_object->size - next_pindex),
2335 ("object %p overcharged 1 %jx %jx", prev_object,
2336 (uintmax_t)next_pindex, (uintmax_t)next_size));
2337 prev_object->charge -= ptoa(prev_object->size -
2344 * Extend the object if necessary.
2346 if (next_pindex + next_size > prev_object->size)
2347 prev_object->size = next_pindex + next_size;
2349 VM_OBJECT_WUNLOCK(prev_object);
2354 vm_object_set_writeable_dirty_(vm_object_t object)
2356 atomic_add_int(&object->generation, 1);
2360 vm_object_mightbedirty_(vm_object_t object)
2362 return (object->generation != object->cleangeneration);
2368 * For each page offset within the specified range of the given object,
2369 * find the highest-level page in the shadow chain and unwire it. A page
2370 * must exist at every page offset, and the highest-level page must be
2374 vm_object_unwire(vm_object_t object, vm_ooffset_t offset, vm_size_t length,
2377 vm_object_t tobject, t1object;
2379 vm_pindex_t end_pindex, pindex, tpindex;
2380 int depth, locked_depth;
2382 KASSERT((offset & PAGE_MASK) == 0,
2383 ("vm_object_unwire: offset is not page aligned"));
2384 KASSERT((length & PAGE_MASK) == 0,
2385 ("vm_object_unwire: length is not a multiple of PAGE_SIZE"));
2386 /* The wired count of a fictitious page never changes. */
2387 if ((object->flags & OBJ_FICTITIOUS) != 0)
2389 pindex = OFF_TO_IDX(offset);
2390 end_pindex = pindex + atop(length);
2393 VM_OBJECT_RLOCK(object);
2394 m = vm_page_find_least(object, pindex);
2395 while (pindex < end_pindex) {
2396 if (m == NULL || pindex < m->pindex) {
2398 * The first object in the shadow chain doesn't
2399 * contain a page at the current index. Therefore,
2400 * the page must exist in a backing object.
2407 OFF_TO_IDX(tobject->backing_object_offset);
2408 tobject = tobject->backing_object;
2409 KASSERT(tobject != NULL,
2410 ("vm_object_unwire: missing page"));
2411 if ((tobject->flags & OBJ_FICTITIOUS) != 0)
2414 if (depth == locked_depth) {
2416 VM_OBJECT_RLOCK(tobject);
2418 } while ((tm = vm_page_lookup(tobject, tpindex)) ==
2422 m = TAILQ_NEXT(m, listq);
2424 if (vm_page_trysbusy(tm) == 0) {
2425 for (tobject = object; locked_depth >= 1;
2427 t1object = tobject->backing_object;
2428 if (tm->object != tobject)
2429 VM_OBJECT_RUNLOCK(tobject);
2432 tobject = tm->object;
2433 if (!vm_page_busy_sleep(tm, "unwbo",
2434 VM_ALLOC_IGN_SBUSY))
2435 VM_OBJECT_RUNLOCK(tobject);
2438 vm_page_unwire(tm, queue);
2439 vm_page_sunbusy(tm);
2443 /* Release the accumulated object locks. */
2444 for (tobject = object; locked_depth >= 1; locked_depth--) {
2445 t1object = tobject->backing_object;
2446 VM_OBJECT_RUNLOCK(tobject);
2452 * Return the vnode for the given object, or NULL if none exists.
2453 * For tmpfs objects, the function may return NULL if there is
2454 * no vnode allocated at the time of the call.
2457 vm_object_vnode(vm_object_t object)
2461 VM_OBJECT_ASSERT_LOCKED(object);
2462 vm_pager_getvp(object, &vp, NULL);
2467 * Busy the vm object. This prevents new pages belonging to the object from
2468 * becoming busy. Existing pages persist as busy. Callers are responsible
2469 * for checking page state before proceeding.
2472 vm_object_busy(vm_object_t obj)
2475 VM_OBJECT_ASSERT_LOCKED(obj);
2477 blockcount_acquire(&obj->busy, 1);
2478 /* The fence is required to order loads of page busy. */
2479 atomic_thread_fence_acq_rel();
2483 vm_object_unbusy(vm_object_t obj)
2486 blockcount_release(&obj->busy, 1);
2490 vm_object_busy_wait(vm_object_t obj, const char *wmesg)
2493 VM_OBJECT_ASSERT_UNLOCKED(obj);
2495 (void)blockcount_sleep(&obj->busy, NULL, wmesg, PVM);
2499 * This function aims to determine if the object is mapped,
2500 * specifically, if it is referenced by a vm_map_entry. Because
2501 * objects occasionally acquire transient references that do not
2502 * represent a mapping, the method used here is inexact. However, it
2503 * has very low overhead and is good enough for the advisory
2504 * vm.vmtotal sysctl.
2507 vm_object_is_active(vm_object_t obj)
2510 return (obj->ref_count > atomic_load_int(&obj->shadow_count));
2514 vm_object_list_handler(struct sysctl_req *req, bool swap_only)
2516 struct kinfo_vmobject *kvo;
2517 char *fullpath, *freepath;
2525 if (req->oldptr == NULL) {
2527 * If an old buffer has not been provided, generate an
2528 * estimate of the space needed for a subsequent call.
2530 mtx_lock(&vm_object_list_mtx);
2532 TAILQ_FOREACH(obj, &vm_object_list, object_list) {
2533 if (obj->type == OBJT_DEAD)
2537 mtx_unlock(&vm_object_list_mtx);
2538 return (SYSCTL_OUT(req, NULL, sizeof(struct kinfo_vmobject) *
2542 kvo = malloc(sizeof(*kvo), M_TEMP, M_WAITOK | M_ZERO);
2546 * VM objects are type stable and are never removed from the
2547 * list once added. This allows us to safely read obj->object_list
2548 * after reacquiring the VM object lock.
2550 mtx_lock(&vm_object_list_mtx);
2551 TAILQ_FOREACH(obj, &vm_object_list, object_list) {
2552 if (obj->type == OBJT_DEAD ||
2553 (swap_only && (obj->flags & (OBJ_ANON | OBJ_SWAP)) == 0))
2555 VM_OBJECT_RLOCK(obj);
2556 if (obj->type == OBJT_DEAD ||
2557 (swap_only && (obj->flags & (OBJ_ANON | OBJ_SWAP)) == 0)) {
2558 VM_OBJECT_RUNLOCK(obj);
2561 mtx_unlock(&vm_object_list_mtx);
2562 kvo->kvo_size = ptoa(obj->size);
2563 kvo->kvo_resident = obj->resident_page_count;
2564 kvo->kvo_ref_count = obj->ref_count;
2565 kvo->kvo_shadow_count = atomic_load_int(&obj->shadow_count);
2566 kvo->kvo_memattr = obj->memattr;
2567 kvo->kvo_active = 0;
2568 kvo->kvo_inactive = 0;
2570 TAILQ_FOREACH(m, &obj->memq, listq) {
2572 * A page may belong to the object but be
2573 * dequeued and set to PQ_NONE while the
2574 * object lock is not held. This makes the
2575 * reads of m->queue below racy, and we do not
2576 * count pages set to PQ_NONE. However, this
2577 * sysctl is only meant to give an
2578 * approximation of the system anyway.
2580 if (m->a.queue == PQ_ACTIVE)
2582 else if (m->a.queue == PQ_INACTIVE)
2583 kvo->kvo_inactive++;
2587 kvo->kvo_vn_fileid = 0;
2588 kvo->kvo_vn_fsid = 0;
2589 kvo->kvo_vn_fsid_freebsd11 = 0;
2593 kvo->kvo_type = vm_object_kvme_type(obj, swap_only ? NULL : &vp);
2596 } else if ((obj->flags & OBJ_ANON) != 0) {
2597 MPASS(kvo->kvo_type == KVME_TYPE_SWAP);
2598 kvo->kvo_me = (uintptr_t)obj;
2599 /* tmpfs objs are reported as vnodes */
2600 kvo->kvo_backing_obj = (uintptr_t)obj->backing_object;
2601 sp = swap_pager_swapped_pages(obj);
2602 kvo->kvo_swapped = sp > UINT32_MAX ? UINT32_MAX : sp;
2604 VM_OBJECT_RUNLOCK(obj);
2606 vn_fullpath(vp, &fullpath, &freepath);
2607 vn_lock(vp, LK_SHARED | LK_RETRY);
2608 if (VOP_GETATTR(vp, &va, curthread->td_ucred) == 0) {
2609 kvo->kvo_vn_fileid = va.va_fileid;
2610 kvo->kvo_vn_fsid = va.va_fsid;
2611 kvo->kvo_vn_fsid_freebsd11 = va.va_fsid;
2617 strlcpy(kvo->kvo_path, fullpath, sizeof(kvo->kvo_path));
2618 if (freepath != NULL)
2619 free(freepath, M_TEMP);
2621 /* Pack record size down */
2622 kvo->kvo_structsize = offsetof(struct kinfo_vmobject, kvo_path)
2623 + strlen(kvo->kvo_path) + 1;
2624 kvo->kvo_structsize = roundup(kvo->kvo_structsize,
2626 error = SYSCTL_OUT(req, kvo, kvo->kvo_structsize);
2628 mtx_lock(&vm_object_list_mtx);
2632 mtx_unlock(&vm_object_list_mtx);
2638 sysctl_vm_object_list(SYSCTL_HANDLER_ARGS)
2640 return (vm_object_list_handler(req, false));
2643 SYSCTL_PROC(_vm, OID_AUTO, objects, CTLTYPE_STRUCT | CTLFLAG_RW | CTLFLAG_SKIP |
2644 CTLFLAG_MPSAFE, NULL, 0, sysctl_vm_object_list, "S,kinfo_vmobject",
2645 "List of VM objects");
2648 sysctl_vm_object_list_swap(SYSCTL_HANDLER_ARGS)
2650 return (vm_object_list_handler(req, true));
2654 * This sysctl returns list of the anonymous or swap objects. Intent
2655 * is to provide stripped optimized list useful to analyze swap use.
2656 * Since technically non-swap (default) objects participate in the
2657 * shadow chains, and are converted to swap type as needed by swap
2658 * pager, we must report them.
2660 SYSCTL_PROC(_vm, OID_AUTO, swap_objects,
2661 CTLTYPE_STRUCT | CTLFLAG_RW | CTLFLAG_SKIP | CTLFLAG_MPSAFE, NULL, 0,
2662 sysctl_vm_object_list_swap, "S,kinfo_vmobject",
2663 "List of swap VM objects");
2665 #include "opt_ddb.h"
2667 #include <sys/kernel.h>
2669 #include <sys/cons.h>
2671 #include <ddb/ddb.h>
2674 _vm_object_in_map(vm_map_t map, vm_object_t object, vm_map_entry_t entry)
2677 vm_map_entry_t tmpe;
2684 VM_MAP_ENTRY_FOREACH(tmpe, map) {
2685 if (_vm_object_in_map(map, object, tmpe)) {
2689 } else if (entry->eflags & MAP_ENTRY_IS_SUB_MAP) {
2690 tmpm = entry->object.sub_map;
2691 VM_MAP_ENTRY_FOREACH(tmpe, tmpm) {
2692 if (_vm_object_in_map(tmpm, object, tmpe)) {
2696 } else if ((obj = entry->object.vm_object) != NULL) {
2697 for (; obj; obj = obj->backing_object)
2698 if (obj == object) {
2706 vm_object_in_map(vm_object_t object)
2710 /* sx_slock(&allproc_lock); */
2711 FOREACH_PROC_IN_SYSTEM(p) {
2712 if (!p->p_vmspace /* || (p->p_flag & (P_SYSTEM|P_WEXIT)) */)
2714 if (_vm_object_in_map(&p->p_vmspace->vm_map, object, 0)) {
2715 /* sx_sunlock(&allproc_lock); */
2719 /* sx_sunlock(&allproc_lock); */
2720 if (_vm_object_in_map(kernel_map, object, 0))
2725 DB_SHOW_COMMAND_FLAGS(vmochk, vm_object_check, DB_CMD_MEMSAFE)
2730 * make sure that internal objs are in a map somewhere
2731 * and none have zero ref counts.
2733 TAILQ_FOREACH(object, &vm_object_list, object_list) {
2734 if ((object->flags & OBJ_ANON) != 0) {
2735 if (object->ref_count == 0) {
2736 db_printf("vmochk: internal obj has zero ref count: %ld\n",
2737 (long)object->size);
2739 if (!vm_object_in_map(object)) {
2741 "vmochk: internal obj is not in a map: "
2742 "ref: %d, size: %lu: 0x%lx, backing_object: %p\n",
2743 object->ref_count, (u_long)object->size,
2744 (u_long)object->size,
2745 (void *)object->backing_object);
2754 * vm_object_print: [ debug ]
2756 DB_SHOW_COMMAND(object, vm_object_print_static)
2758 /* XXX convert args. */
2759 vm_object_t object = (vm_object_t)addr;
2760 boolean_t full = have_addr;
2764 /* XXX count is an (unused) arg. Avoid shadowing it. */
2765 #define count was_count
2773 "Object %p: type=%d, size=0x%jx, res=%d, ref=%d, flags=0x%x ruid %d charge %jx\n",
2774 object, (int)object->type, (uintmax_t)object->size,
2775 object->resident_page_count, object->ref_count, object->flags,
2776 object->cred ? object->cred->cr_ruid : -1, (uintmax_t)object->charge);
2777 db_iprintf(" sref=%d, backing_object(%d)=(%p)+0x%jx\n",
2778 atomic_load_int(&object->shadow_count),
2779 object->backing_object ? object->backing_object->ref_count : 0,
2780 object->backing_object, (uintmax_t)object->backing_object_offset);
2787 TAILQ_FOREACH(p, &object->memq, listq) {
2789 db_iprintf("memory:=");
2790 else if (count == 6) {
2798 db_printf("(off=0x%jx,page=0x%jx)",
2799 (uintmax_t)p->pindex, (uintmax_t)VM_PAGE_TO_PHYS(p));
2812 /* XXX need this non-static entry for calling from vm_map_print. */
2815 /* db_expr_t */ long addr,
2816 boolean_t have_addr,
2817 /* db_expr_t */ long count,
2820 vm_object_print_static(addr, have_addr, count, modif);
2823 DB_SHOW_COMMAND_FLAGS(vmopag, vm_object_print_pages, DB_CMD_MEMSAFE)
2828 vm_page_t m, prev_m;
2831 TAILQ_FOREACH(object, &vm_object_list, object_list) {
2832 db_printf("new object: %p\n", (void *)object);
2839 TAILQ_FOREACH(m, &object->memq, listq) {
2840 if ((prev_m = TAILQ_PREV(m, pglist, listq)) != NULL &&
2841 prev_m->pindex + 1 != m->pindex) {
2843 db_printf(" index(%ld)run(%d)pa(0x%lx)\n",
2844 (long)fidx, rcount, (long)pa);
2851 (VM_PAGE_TO_PHYS(m) == pa + rcount * PAGE_SIZE)) {
2856 db_printf(" index(%ld)run(%d)pa(0x%lx)\n",
2857 (long)fidx, rcount, (long)pa);
2862 pa = VM_PAGE_TO_PHYS(m);
2866 db_printf(" index(%ld)run(%d)pa(0x%lx)\n",
2867 (long)fidx, rcount, (long)pa);