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 * 3. All advertising materials mentioning features or use of this software
17 * must display the following acknowledgement:
18 * This product includes software developed by the University of
19 * California, Berkeley and its contributors.
20 * 4. Neither the name of the University nor the names of its contributors
21 * may be used to endorse or promote products derived from this software
22 * without specific prior written permission.
24 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
25 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
26 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
27 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
28 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
29 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
30 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
31 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
32 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
33 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
36 * from: @(#)vm_object.c 8.5 (Berkeley) 3/22/94
39 * Copyright (c) 1987, 1990 Carnegie-Mellon University.
40 * All rights reserved.
42 * Authors: Avadis Tevanian, Jr., Michael Wayne Young
44 * Permission to use, copy, modify and distribute this software and
45 * its documentation is hereby granted, provided that both the copyright
46 * notice and this permission notice appear in all copies of the
47 * software, derivative works or modified versions, and any portions
48 * thereof, and that both notices appear in supporting documentation.
50 * CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS"
51 * CONDITION. CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND
52 * FOR ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
54 * Carnegie Mellon requests users of this software to return to
56 * Software Distribution Coordinator or Software.Distribution@CS.CMU.EDU
57 * School of Computer Science
58 * Carnegie Mellon University
59 * Pittsburgh PA 15213-3890
61 * any improvements or extensions that they make and grant Carnegie the
62 * rights to redistribute these changes.
64 * $FreeBSD: src/sys/vm/vm_object.c,v 1.171.2.8 2003/05/26 19:17:56 alc Exp $
65 * $DragonFly: src/sys/vm/vm_object.c,v 1.27 2006/12/02 23:13:46 dillon Exp $
69 * Virtual memory object module.
72 #include <sys/param.h>
73 #include <sys/systm.h>
74 #include <sys/proc.h> /* for curproc, pageproc */
75 #include <sys/vnode.h>
76 #include <sys/vmmeter.h>
78 #include <sys/mount.h>
79 #include <sys/kernel.h>
80 #include <sys/sysctl.h>
83 #include <vm/vm_param.h>
85 #include <vm/vm_map.h>
86 #include <vm/vm_object.h>
87 #include <vm/vm_page.h>
88 #include <vm/vm_pageout.h>
89 #include <vm/vm_pager.h>
90 #include <vm/swap_pager.h>
91 #include <vm/vm_kern.h>
92 #include <vm/vm_extern.h>
93 #include <vm/vm_zone.h>
95 #define EASY_SCAN_FACTOR 8
97 static void vm_object_qcollapse(vm_object_t object);
98 static int vm_object_page_collect_flush(vm_object_t object, vm_page_t p,
102 * Virtual memory objects maintain the actual data
103 * associated with allocated virtual memory. A given
104 * page of memory exists within exactly one object.
106 * An object is only deallocated when all "references"
107 * are given up. Only one "reference" to a given
108 * region of an object should be writeable.
110 * Associated with each object is a list of all resident
111 * memory pages belonging to that object; this list is
112 * maintained by the "vm_page" module, and locked by the object's
115 * Each object also records a "pager" routine which is
116 * used to retrieve (and store) pages to the proper backing
117 * storage. In addition, objects may be backed by other
118 * objects from which they were virtual-copied.
120 * The only items within the object structure which are
121 * modified after time of creation are:
122 * reference count locked by object's lock
123 * pager routine locked by object's lock
127 struct object_q vm_object_list;
128 static long vm_object_count; /* count of all objects */
129 vm_object_t kernel_object;
130 vm_object_t kmem_object;
131 static struct vm_object kernel_object_store;
132 static struct vm_object kmem_object_store;
133 extern int vm_pageout_page_count;
135 static long object_collapses;
136 static long object_bypasses;
137 static int next_index;
138 static vm_zone_t obj_zone;
139 static struct vm_zone obj_zone_store;
140 static int object_hash_rand;
141 #define VM_OBJECTS_INIT 256
142 static struct vm_object vm_objects_init[VM_OBJECTS_INIT];
145 _vm_object_allocate(objtype_t type, vm_size_t size, vm_object_t object)
148 RB_INIT(&object->rb_memq);
149 LIST_INIT(&object->shadow_head);
153 object->ref_count = 1;
155 if ((object->type == OBJT_DEFAULT) || (object->type == OBJT_SWAP))
156 vm_object_set_flag(object, OBJ_ONEMAPPING);
157 object->paging_in_progress = 0;
158 object->resident_page_count = 0;
159 object->shadow_count = 0;
160 object->pg_color = next_index;
161 if ( size > (PQ_L2_SIZE / 3 + PQ_PRIME1))
162 incr = PQ_L2_SIZE / 3 + PQ_PRIME1;
165 next_index = (next_index + incr) & PQ_L2_MASK;
166 object->handle = NULL;
167 object->backing_object = NULL;
168 object->backing_object_offset = (vm_ooffset_t) 0;
170 * Try to generate a number that will spread objects out in the
171 * hash table. We 'wipe' new objects across the hash in 128 page
172 * increments plus 1 more to offset it a little more by the time
175 object->hash_rand = object_hash_rand - 129;
177 object->generation++;
180 TAILQ_INSERT_TAIL(&vm_object_list, object, object_list);
182 object_hash_rand = object->hash_rand;
189 * Initialize the VM objects module.
194 TAILQ_INIT(&vm_object_list);
196 kernel_object = &kernel_object_store;
197 _vm_object_allocate(OBJT_DEFAULT, OFF_TO_IDX(VM_MAX_KERNEL_ADDRESS - VM_MIN_KERNEL_ADDRESS),
200 kmem_object = &kmem_object_store;
201 _vm_object_allocate(OBJT_DEFAULT, OFF_TO_IDX(VM_MAX_KERNEL_ADDRESS - VM_MIN_KERNEL_ADDRESS),
204 obj_zone = &obj_zone_store;
205 zbootinit(obj_zone, "VM OBJECT", sizeof (struct vm_object),
206 vm_objects_init, VM_OBJECTS_INIT);
210 vm_object_init2(void)
212 zinitna(obj_zone, NULL, NULL, 0, 0, ZONE_PANICFAIL, 1);
216 * vm_object_allocate:
218 * Returns a new object with the given size.
222 vm_object_allocate(objtype_t type, vm_size_t size)
226 result = (vm_object_t) zalloc(obj_zone);
228 _vm_object_allocate(type, size, result);
235 * vm_object_reference:
237 * Gets another reference to the given object.
240 vm_object_reference(vm_object_t object)
246 if (object->type == OBJT_VNODE) {
247 vref(object->handle);
248 /* XXX what if the vnode is being destroyed? */
253 vm_object_vndeallocate(vm_object_t object)
255 struct vnode *vp = (struct vnode *) object->handle;
257 KASSERT(object->type == OBJT_VNODE,
258 ("vm_object_vndeallocate: not a vnode object"));
259 KASSERT(vp != NULL, ("vm_object_vndeallocate: missing vp"));
261 if (object->ref_count == 0) {
262 vprint("vm_object_vndeallocate", vp);
263 panic("vm_object_vndeallocate: bad object reference count");
268 if (object->ref_count == 0)
269 vp->v_flag &= ~VTEXT;
274 * vm_object_deallocate:
276 * Release a reference to the specified object,
277 * gained either through a vm_object_allocate
278 * or a vm_object_reference call. When all references
279 * are gone, storage associated with this object
280 * may be relinquished.
282 * No object may be locked.
285 vm_object_deallocate(vm_object_t object)
289 while (object != NULL) {
290 if (object->type == OBJT_VNODE) {
291 vm_object_vndeallocate(object);
295 if (object->ref_count == 0) {
296 panic("vm_object_deallocate: object deallocated too many times: %d", object->type);
297 } else if (object->ref_count > 2) {
303 * Here on ref_count of one or two, which are special cases for
306 if ((object->ref_count == 2) && (object->shadow_count == 0)) {
307 vm_object_set_flag(object, OBJ_ONEMAPPING);
310 } else if ((object->ref_count == 2) && (object->shadow_count == 1)) {
312 if ((object->handle == NULL) &&
313 (object->type == OBJT_DEFAULT ||
314 object->type == OBJT_SWAP)) {
317 robject = LIST_FIRST(&object->shadow_head);
318 KASSERT(robject != NULL,
319 ("vm_object_deallocate: ref_count: %d, shadow_count: %d",
321 object->shadow_count));
322 if ((robject->handle == NULL) &&
323 (robject->type == OBJT_DEFAULT ||
324 robject->type == OBJT_SWAP)) {
326 robject->ref_count++;
329 robject->paging_in_progress ||
330 object->paging_in_progress
332 vm_object_pip_sleep(robject, "objde1");
333 vm_object_pip_sleep(object, "objde2");
336 if (robject->ref_count == 1) {
337 robject->ref_count--;
343 vm_object_collapse(object);
352 if (object->ref_count != 0)
358 temp = object->backing_object;
360 LIST_REMOVE(object, shadow_list);
361 temp->shadow_count--;
363 object->backing_object = NULL;
367 * Don't double-terminate, we could be in a termination
368 * recursion due to the terminate having to sync data
371 if ((object->flags & OBJ_DEAD) == 0)
372 vm_object_terminate(object);
378 * vm_object_terminate actually destroys the specified object, freeing
379 * up all previously used resources.
381 * The object must be locked.
382 * This routine may block.
384 static int vm_object_terminate_callback(vm_page_t p, void *data);
387 vm_object_terminate(vm_object_t object)
390 * Make sure no one uses us.
392 vm_object_set_flag(object, OBJ_DEAD);
395 * wait for the pageout daemon to be done with the object
397 vm_object_pip_wait(object, "objtrm");
399 KASSERT(!object->paging_in_progress,
400 ("vm_object_terminate: pageout in progress"));
403 * Clean and free the pages, as appropriate. All references to the
404 * object are gone, so we don't need to lock it.
406 if (object->type == OBJT_VNODE) {
410 * Clean pages and flush buffers.
412 vm_object_page_clean(object, 0, 0, OBJPC_SYNC);
414 vp = (struct vnode *) object->handle;
415 vinvalbuf(vp, V_SAVE, 0, 0);
419 * Wait for any I/O to complete, after which there had better not
420 * be any references left on the object.
422 vm_object_pip_wait(object, "objtrm");
424 if (object->ref_count != 0)
425 panic("vm_object_terminate: object with references, ref_count=%d", object->ref_count);
428 * Now free any remaining pages. For internal objects, this also
429 * removes them from paging queues. Don't free wired pages, just
430 * remove them from the object.
433 vm_page_rb_tree_RB_SCAN(&object->rb_memq, NULL,
434 vm_object_terminate_callback, NULL);
438 * Let the pager know object is dead.
440 vm_pager_deallocate(object);
443 * Remove the object from the global object list.
446 TAILQ_REMOVE(&vm_object_list, object, object_list);
451 if (object->ref_count != 0)
452 panic("vm_object_terminate2: object with references, ref_count=%d", object->ref_count);
455 * Free the space for the object.
457 zfree(obj_zone, object);
461 vm_object_terminate_callback(vm_page_t p, void *data __unused)
463 if (p->busy || (p->flags & PG_BUSY))
464 panic("vm_object_terminate: freeing busy page %p", p);
465 if (p->wire_count == 0) {
468 mycpu->gd_cnt.v_pfree++;
478 * vm_object_page_clean
480 * Clean all dirty pages in the specified range of object. Leaves page
481 * on whatever queue it is currently on. If NOSYNC is set then do not
482 * write out pages with PG_NOSYNC set (originally comes from MAP_NOSYNC),
483 * leaving the object dirty.
485 * When stuffing pages asynchronously, allow clustering. XXX we need a
486 * synchronous clustering mode implementation.
488 * Odd semantics: if start == end, we clean everything.
490 static int vm_object_page_clean_pass1(struct vm_page *p, void *data);
491 static int vm_object_page_clean_pass2(struct vm_page *p, void *data);
494 vm_object_page_clean(vm_object_t object, vm_pindex_t start, vm_pindex_t end,
497 struct rb_vm_page_scan_info info;
503 if (object->type != OBJT_VNODE ||
504 (object->flags & OBJ_MIGHTBEDIRTY) == 0)
507 pagerflags = (flags & (OBJPC_SYNC | OBJPC_INVAL)) ?
508 VM_PAGER_PUT_SYNC : VM_PAGER_CLUSTER_OK;
509 pagerflags |= (flags & OBJPC_INVAL) ? VM_PAGER_PUT_INVAL : 0;
514 * Interlock other major object operations. This allows us to
515 * temporarily clear OBJ_WRITEABLE and OBJ_MIGHTBEDIRTY.
518 vm_object_set_flag(object, OBJ_CLEANING);
521 * Handle 'entire object' case
523 info.start_pindex = start;
525 info.end_pindex = object->size - 1;
527 info.end_pindex = end - 1;
529 wholescan = (start == 0 && info.end_pindex == object->size - 1);
531 info.pagerflags = pagerflags;
532 info.object = object;
535 * If cleaning the entire object do a pass to mark the pages read-only.
536 * If everything worked out ok, clear OBJ_WRITEABLE and
541 vm_page_rb_tree_RB_SCAN(&object->rb_memq, rb_vm_page_scancmp,
542 vm_object_page_clean_pass1, &info);
543 if (info.error == 0) {
544 vm_object_clear_flag(object,
545 OBJ_WRITEABLE|OBJ_MIGHTBEDIRTY);
546 if (object->type == OBJT_VNODE &&
547 (vp = (struct vnode *)object->handle) != NULL) {
548 if (vp->v_flag & VOBJDIRTY)
549 vclrflags(vp, VOBJDIRTY);
555 * Do a pass to clean all the dirty pages we find.
559 curgeneration = object->generation;
560 vm_page_rb_tree_RB_SCAN(&object->rb_memq, rb_vm_page_scancmp,
561 vm_object_page_clean_pass2, &info);
562 } while (info.error || curgeneration != object->generation);
564 vm_object_clear_flag(object, OBJ_CLEANING);
570 vm_object_page_clean_pass1(struct vm_page *p, void *data)
572 struct rb_vm_page_scan_info *info = data;
574 vm_page_flag_set(p, PG_CLEANCHK);
575 if ((info->limit & OBJPC_NOSYNC) && (p->flags & PG_NOSYNC))
578 vm_page_protect(p, VM_PROT_READ);
584 vm_object_page_clean_pass2(struct vm_page *p, void *data)
586 struct rb_vm_page_scan_info *info = data;
590 * Do not mess with pages that were inserted after we started
593 if ((p->flags & PG_CLEANCHK) == 0)
597 * Before wasting time traversing the pmaps, check for trivial
598 * cases where the page cannot be dirty.
600 if (p->valid == 0 || (p->queue - p->pc) == PQ_CACHE) {
601 KKASSERT((p->dirty & p->valid) == 0);
606 * Check whether the page is dirty or not. The page has been set
607 * to be read-only so the check will not race a user dirtying the
610 vm_page_test_dirty(p);
611 if ((p->dirty & p->valid) == 0) {
612 vm_page_flag_clear(p, PG_CLEANCHK);
617 * If we have been asked to skip nosync pages and this is a
618 * nosync page, skip it. Note that the object flags were
619 * not cleared in this case (because pass1 will have returned an
620 * error), so we do not have to set them.
622 if ((info->limit & OBJPC_NOSYNC) && (p->flags & PG_NOSYNC)) {
623 vm_page_flag_clear(p, PG_CLEANCHK);
628 * Flush as many pages as we can. PG_CLEANCHK will be cleared on
629 * the pages that get successfully flushed. Set info->error if
630 * we raced an object modification.
632 n = vm_object_page_collect_flush(info->object, p, info->pagerflags);
639 * This routine must be called within a critical section to properly avoid
640 * an interrupt unbusy/free race that can occur prior to the busy check.
642 * Using the object generation number here to detect page ripout is not
643 * the best idea in the world. XXX
645 * NOTE: we operate under the assumption that a page found to not be busy
646 * will not be ripped out from under us by an interrupt. XXX we should
647 * recode this to explicitly busy the pages.
650 vm_object_page_collect_flush(vm_object_t object, vm_page_t p, int pagerflags)
659 vm_page_t maf[vm_pageout_page_count];
660 vm_page_t mab[vm_pageout_page_count];
661 vm_page_t ma[vm_pageout_page_count];
663 curgeneration = object->generation;
666 while (vm_page_sleep_busy(p, TRUE, "vpcwai")) {
667 if (object->generation != curgeneration) {
671 KKASSERT(p->object == object && p->pindex == pi);
674 for(i = 1; i < vm_pageout_page_count; i++) {
677 if ((tp = vm_page_lookup(object, pi + i)) != NULL) {
678 if ((tp->flags & PG_BUSY) ||
679 ((pagerflags & VM_PAGER_IGNORE_CLEANCHK) == 0 &&
680 (tp->flags & PG_CLEANCHK) == 0) ||
683 if((tp->queue - tp->pc) == PQ_CACHE) {
684 vm_page_flag_clear(tp, PG_CLEANCHK);
687 vm_page_test_dirty(tp);
688 if ((tp->dirty & tp->valid) == 0) {
689 vm_page_flag_clear(tp, PG_CLEANCHK);
700 chkb = vm_pageout_page_count - maxf;
702 for(i = 1; i < chkb;i++) {
705 if ((tp = vm_page_lookup(object, pi - i)) != NULL) {
706 if ((tp->flags & PG_BUSY) ||
707 ((pagerflags & VM_PAGER_IGNORE_CLEANCHK) == 0 &&
708 (tp->flags & PG_CLEANCHK) == 0) ||
711 if((tp->queue - tp->pc) == PQ_CACHE) {
712 vm_page_flag_clear(tp, PG_CLEANCHK);
715 vm_page_test_dirty(tp);
716 if ((tp->dirty & tp->valid) == 0) {
717 vm_page_flag_clear(tp, PG_CLEANCHK);
728 for(i = 0; i < maxb; i++) {
729 int index = (maxb - i) - 1;
731 vm_page_flag_clear(ma[index], PG_CLEANCHK);
733 vm_page_flag_clear(p, PG_CLEANCHK);
735 for(i = 0; i < maxf; i++) {
736 int index = (maxb + i) + 1;
738 vm_page_flag_clear(ma[index], PG_CLEANCHK);
740 runlen = maxb + maxf + 1;
742 vm_pageout_flush(ma, runlen, pagerflags);
743 for (i = 0; i < runlen; i++) {
744 if (ma[i]->valid & ma[i]->dirty) {
745 vm_page_protect(ma[i], VM_PROT_READ);
746 vm_page_flag_set(ma[i], PG_CLEANCHK);
749 * maxf will end up being the actual number of pages
750 * we wrote out contiguously, non-inclusive of the
751 * first page. We do not count look-behind pages.
753 if (i >= maxb + 1 && (maxf > i - maxb - 1))
761 /* XXX I cannot tell if this should be an exported symbol */
763 * vm_object_deactivate_pages
765 * Deactivate all pages in the specified object. (Keep its pages
766 * in memory even though it is no longer referenced.)
768 * The object must be locked.
770 static int vm_object_deactivate_pages_callback(vm_page_t p, void *data);
773 vm_object_deactivate_pages(vm_object_t object)
776 vm_page_rb_tree_RB_SCAN(&object->rb_memq, NULL,
777 vm_object_deactivate_pages_callback, NULL);
782 vm_object_deactivate_pages_callback(vm_page_t p, void *data __unused)
784 vm_page_deactivate(p);
791 * Same as vm_object_pmap_copy, except range checking really
792 * works, and is meant for small sections of an object.
794 * This code protects resident pages by making them read-only
795 * and is typically called on a fork or split when a page
796 * is converted to copy-on-write.
798 * NOTE: If the page is already at VM_PROT_NONE, calling
799 * vm_page_protect will have no effect.
802 vm_object_pmap_copy_1(vm_object_t object, vm_pindex_t start, vm_pindex_t end)
807 if (object == NULL || (object->flags & OBJ_WRITEABLE) == 0)
811 * spl protection needed to prevent races between the lookup,
812 * an interrupt unbusy/free, and our protect call.
815 for (idx = start; idx < end; idx++) {
816 p = vm_page_lookup(object, idx);
819 vm_page_protect(p, VM_PROT_READ);
825 * vm_object_pmap_remove:
827 * Removes all physical pages in the specified
828 * object range from all physical maps.
830 * The object must *not* be locked.
833 static int vm_object_pmap_remove_callback(vm_page_t p, void *data);
836 vm_object_pmap_remove(vm_object_t object, vm_pindex_t start, vm_pindex_t end)
838 struct rb_vm_page_scan_info info;
842 info.start_pindex = start;
843 info.end_pindex = end - 1;
845 vm_page_rb_tree_RB_SCAN(&object->rb_memq, rb_vm_page_scancmp,
846 vm_object_pmap_remove_callback, &info);
847 if (start == 0 && end == object->size)
848 vm_object_clear_flag(object, OBJ_WRITEABLE);
853 vm_object_pmap_remove_callback(vm_page_t p, void *data __unused)
855 vm_page_protect(p, VM_PROT_NONE);
862 * Implements the madvise function at the object/page level.
864 * MADV_WILLNEED (any object)
866 * Activate the specified pages if they are resident.
868 * MADV_DONTNEED (any object)
870 * Deactivate the specified pages if they are resident.
872 * MADV_FREE (OBJT_DEFAULT/OBJT_SWAP objects,
873 * OBJ_ONEMAPPING only)
875 * Deactivate and clean the specified pages if they are
876 * resident. This permits the process to reuse the pages
877 * without faulting or the kernel to reclaim the pages
881 vm_object_madvise(vm_object_t object, vm_pindex_t pindex, int count, int advise)
883 vm_pindex_t end, tpindex;
890 end = pindex + count;
893 * Locate and adjust resident pages
896 for (; pindex < end; pindex += 1) {
902 * MADV_FREE only operates on OBJT_DEFAULT or OBJT_SWAP pages
903 * and those pages must be OBJ_ONEMAPPING.
905 if (advise == MADV_FREE) {
906 if ((tobject->type != OBJT_DEFAULT &&
907 tobject->type != OBJT_SWAP) ||
908 (tobject->flags & OBJ_ONEMAPPING) == 0) {
914 * spl protection is required to avoid a race between the
915 * lookup, an interrupt unbusy/free, and our busy check.
919 m = vm_page_lookup(tobject, tpindex);
923 * There may be swap even if there is no backing page
925 if (advise == MADV_FREE && tobject->type == OBJT_SWAP)
926 swap_pager_freespace(tobject, tpindex, 1);
932 if (tobject->backing_object == NULL)
934 tpindex += OFF_TO_IDX(tobject->backing_object_offset);
935 tobject = tobject->backing_object;
940 * If the page is busy or not in a normal active state,
941 * we skip it. If the page is not managed there are no
942 * page queues to mess with. Things can break if we mess
943 * with pages in any of the below states.
948 (m->flags & PG_UNMANAGED) ||
949 m->valid != VM_PAGE_BITS_ALL
955 if (vm_page_sleep_busy(m, TRUE, "madvpo")) {
962 * Theoretically once a page is known not to be busy, an
963 * interrupt cannot come along and rip it out from under us.
966 if (advise == MADV_WILLNEED) {
968 } else if (advise == MADV_DONTNEED) {
970 } else if (advise == MADV_FREE) {
972 * Mark the page clean. This will allow the page
973 * to be freed up by the system. However, such pages
974 * are often reused quickly by malloc()/free()
975 * so we do not do anything that would cause
976 * a page fault if we can help it.
978 * Specifically, we do not try to actually free
979 * the page now nor do we try to put it in the
980 * cache (which would cause a page fault on reuse).
982 * But we do make the page is freeable as we
983 * can without actually taking the step of unmapping
986 pmap_clear_modify(m);
990 if (tobject->type == OBJT_SWAP)
991 swap_pager_freespace(tobject, tpindex, 1);
999 * Create a new object which is backed by the
1000 * specified existing object range. The source
1001 * object reference is deallocated.
1003 * The new object and offset into that object
1004 * are returned in the source parameters.
1008 vm_object_shadow(vm_object_t *object, /* IN/OUT */
1009 vm_ooffset_t *offset, /* IN/OUT */
1018 * Don't create the new object if the old object isn't shared.
1021 if (source != NULL &&
1022 source->ref_count == 1 &&
1023 source->handle == NULL &&
1024 (source->type == OBJT_DEFAULT ||
1025 source->type == OBJT_SWAP))
1029 * Allocate a new object with the given length
1032 if ((result = vm_object_allocate(OBJT_DEFAULT, length)) == NULL)
1033 panic("vm_object_shadow: no object for shadowing");
1036 * The new object shadows the source object, adding a reference to it.
1037 * Our caller changes his reference to point to the new object,
1038 * removing a reference to the source object. Net result: no change
1039 * of reference count.
1041 * Try to optimize the result object's page color when shadowing
1042 * in order to maintain page coloring consistency in the combined
1045 result->backing_object = source;
1047 LIST_INSERT_HEAD(&source->shadow_head, result, shadow_list);
1048 source->shadow_count++;
1049 source->generation++;
1050 result->pg_color = (source->pg_color + OFF_TO_IDX(*offset)) & PQ_L2_MASK;
1054 * Store the offset into the source object, and fix up the offset into
1058 result->backing_object_offset = *offset;
1061 * Return the new things
1068 #define OBSC_TEST_ALL_SHADOWED 0x0001
1069 #define OBSC_COLLAPSE_NOWAIT 0x0002
1070 #define OBSC_COLLAPSE_WAIT 0x0004
1072 static int vm_object_backing_scan_callback(vm_page_t p, void *data);
1075 vm_object_backing_scan(vm_object_t object, int op)
1077 struct rb_vm_page_scan_info info;
1078 vm_object_t backing_object;
1081 * spl protection is required to avoid races between the memq/lookup,
1082 * an interrupt doing an unbusy/free, and our busy check. Amoung
1087 backing_object = object->backing_object;
1088 info.backing_offset_index = OFF_TO_IDX(object->backing_object_offset);
1091 * Initial conditions
1094 if (op & OBSC_TEST_ALL_SHADOWED) {
1096 * We do not want to have to test for the existence of
1097 * swap pages in the backing object. XXX but with the
1098 * new swapper this would be pretty easy to do.
1100 * XXX what about anonymous MAP_SHARED memory that hasn't
1101 * been ZFOD faulted yet? If we do not test for this, the
1102 * shadow test may succeed! XXX
1104 if (backing_object->type != OBJT_DEFAULT) {
1109 if (op & OBSC_COLLAPSE_WAIT) {
1110 KKASSERT((backing_object->flags & OBJ_DEAD) == 0);
1111 vm_object_set_flag(backing_object, OBJ_DEAD);
1115 * Our scan. We have to retry if a negative error code is returned,
1116 * otherwise 0 or 1 will be returned in info.error. 0 Indicates that
1117 * the scan had to be stopped because the parent does not completely
1120 info.object = object;
1121 info.backing_object = backing_object;
1125 vm_page_rb_tree_RB_SCAN(&backing_object->rb_memq, NULL,
1126 vm_object_backing_scan_callback,
1128 } while (info.error < 0);
1134 vm_object_backing_scan_callback(vm_page_t p, void *data)
1136 struct rb_vm_page_scan_info *info = data;
1137 vm_object_t backing_object;
1139 vm_pindex_t new_pindex;
1140 vm_pindex_t backing_offset_index;
1143 new_pindex = p->pindex - info->backing_offset_index;
1145 object = info->object;
1146 backing_object = info->backing_object;
1147 backing_offset_index = info->backing_offset_index;
1149 if (op & OBSC_TEST_ALL_SHADOWED) {
1153 * Ignore pages outside the parent object's range
1154 * and outside the parent object's mapping of the
1157 * note that we do not busy the backing object's
1161 p->pindex < backing_offset_index ||
1162 new_pindex >= object->size
1168 * See if the parent has the page or if the parent's
1169 * object pager has the page. If the parent has the
1170 * page but the page is not valid, the parent's
1171 * object pager must have the page.
1173 * If this fails, the parent does not completely shadow
1174 * the object and we might as well give up now.
1177 pp = vm_page_lookup(object, new_pindex);
1179 (pp == NULL || pp->valid == 0) &&
1180 !vm_pager_has_page(object, new_pindex, NULL, NULL)
1182 info->error = 0; /* problemo */
1183 return(-1); /* stop the scan */
1188 * Check for busy page
1191 if (op & (OBSC_COLLAPSE_WAIT | OBSC_COLLAPSE_NOWAIT)) {
1194 if (op & OBSC_COLLAPSE_NOWAIT) {
1196 (p->flags & PG_BUSY) ||
1204 } else if (op & OBSC_COLLAPSE_WAIT) {
1205 if (vm_page_sleep_busy(p, TRUE, "vmocol")) {
1207 * If we slept, anything could have
1208 * happened. Ask that the scan be restarted.
1210 * Since the object is marked dead, the
1211 * backing offset should not have changed.
1224 p->object == backing_object,
1225 ("vm_object_qcollapse(): object mismatch")
1229 * Destroy any associated swap
1231 if (backing_object->type == OBJT_SWAP) {
1232 swap_pager_freespace(
1240 p->pindex < backing_offset_index ||
1241 new_pindex >= object->size
1244 * Page is out of the parent object's range, we
1245 * can simply destroy it.
1247 vm_page_protect(p, VM_PROT_NONE);
1252 pp = vm_page_lookup(object, new_pindex);
1255 vm_pager_has_page(object, new_pindex, NULL, NULL)
1258 * page already exists in parent OR swap exists
1259 * for this location in the parent. Destroy
1260 * the original page from the backing object.
1262 * Leave the parent's page alone
1264 vm_page_protect(p, VM_PROT_NONE);
1270 * Page does not exist in parent, rename the
1271 * page from the backing object to the main object.
1273 * If the page was mapped to a process, it can remain
1274 * mapped through the rename.
1276 if ((p->queue - p->pc) == PQ_CACHE)
1277 vm_page_deactivate(p);
1279 vm_page_rename(p, object, new_pindex);
1280 /* page automatically made dirty by rename */
1286 * this version of collapse allows the operation to occur earlier and
1287 * when paging_in_progress is true for an object... This is not a complete
1288 * operation, but should plug 99.9% of the rest of the leaks.
1291 vm_object_qcollapse(vm_object_t object)
1293 vm_object_t backing_object = object->backing_object;
1295 if (backing_object->ref_count != 1)
1298 backing_object->ref_count += 2;
1300 vm_object_backing_scan(object, OBSC_COLLAPSE_NOWAIT);
1302 backing_object->ref_count -= 2;
1306 * vm_object_collapse:
1308 * Collapse an object with the object backing it.
1309 * Pages in the backing object are moved into the
1310 * parent, and the backing object is deallocated.
1313 vm_object_collapse(vm_object_t object)
1316 vm_object_t backing_object;
1319 * Verify that the conditions are right for collapse:
1321 * The object exists and the backing object exists.
1326 if ((backing_object = object->backing_object) == NULL)
1330 * we check the backing object first, because it is most likely
1333 if (backing_object->handle != NULL ||
1334 (backing_object->type != OBJT_DEFAULT &&
1335 backing_object->type != OBJT_SWAP) ||
1336 (backing_object->flags & OBJ_DEAD) ||
1337 object->handle != NULL ||
1338 (object->type != OBJT_DEFAULT &&
1339 object->type != OBJT_SWAP) ||
1340 (object->flags & OBJ_DEAD)) {
1345 object->paging_in_progress != 0 ||
1346 backing_object->paging_in_progress != 0
1348 vm_object_qcollapse(object);
1353 * We know that we can either collapse the backing object (if
1354 * the parent is the only reference to it) or (perhaps) have
1355 * the parent bypass the object if the parent happens to shadow
1356 * all the resident pages in the entire backing object.
1358 * This is ignoring pager-backed pages such as swap pages.
1359 * vm_object_backing_scan fails the shadowing test in this
1363 if (backing_object->ref_count == 1) {
1365 * If there is exactly one reference to the backing
1366 * object, we can collapse it into the parent.
1368 vm_object_backing_scan(object, OBSC_COLLAPSE_WAIT);
1371 * Move the pager from backing_object to object.
1374 if (backing_object->type == OBJT_SWAP) {
1375 vm_object_pip_add(backing_object, 1);
1378 * scrap the paging_offset junk and do a
1379 * discrete copy. This also removes major
1380 * assumptions about how the swap-pager
1381 * works from where it doesn't belong. The
1382 * new swapper is able to optimize the
1383 * destroy-source case.
1386 vm_object_pip_add(object, 1);
1390 OFF_TO_IDX(object->backing_object_offset), TRUE);
1391 vm_object_pip_wakeup(object);
1393 vm_object_pip_wakeup(backing_object);
1396 * Object now shadows whatever backing_object did.
1397 * Note that the reference to
1398 * backing_object->backing_object moves from within
1399 * backing_object to within object.
1402 LIST_REMOVE(object, shadow_list);
1403 object->backing_object->shadow_count--;
1404 object->backing_object->generation++;
1405 if (backing_object->backing_object) {
1406 LIST_REMOVE(backing_object, shadow_list);
1407 backing_object->backing_object->shadow_count--;
1408 backing_object->backing_object->generation++;
1410 object->backing_object = backing_object->backing_object;
1411 if (object->backing_object) {
1413 &object->backing_object->shadow_head,
1417 object->backing_object->shadow_count++;
1418 object->backing_object->generation++;
1421 object->backing_object_offset +=
1422 backing_object->backing_object_offset;
1425 * Discard backing_object.
1427 * Since the backing object has no pages, no pager left,
1428 * and no object references within it, all that is
1429 * necessary is to dispose of it.
1432 KASSERT(backing_object->ref_count == 1, ("backing_object %p was somehow re-referenced during collapse!", backing_object));
1433 KASSERT(RB_EMPTY(&backing_object->rb_memq), ("backing_object %p somehow has left over pages during collapse!", backing_object));
1443 zfree(obj_zone, backing_object);
1447 vm_object_t new_backing_object;
1450 * If we do not entirely shadow the backing object,
1451 * there is nothing we can do so we give up.
1454 if (vm_object_backing_scan(object, OBSC_TEST_ALL_SHADOWED) == 0) {
1459 * Make the parent shadow the next object in the
1460 * chain. Deallocating backing_object will not remove
1461 * it, since its reference count is at least 2.
1464 LIST_REMOVE(object, shadow_list);
1465 backing_object->shadow_count--;
1466 backing_object->generation++;
1468 new_backing_object = backing_object->backing_object;
1469 if ((object->backing_object = new_backing_object) != NULL) {
1470 vm_object_reference(new_backing_object);
1472 &new_backing_object->shadow_head,
1476 new_backing_object->shadow_count++;
1477 new_backing_object->generation++;
1478 object->backing_object_offset +=
1479 backing_object->backing_object_offset;
1483 * Drop the reference count on backing_object. Since
1484 * its ref_count was at least 2, it will not vanish;
1485 * so we don't need to call vm_object_deallocate, but
1488 vm_object_deallocate(backing_object);
1493 * Try again with this object's new backing object.
1499 * vm_object_page_remove: [internal]
1501 * Removes all physical pages in the specified
1502 * object range from the object's list of pages.
1504 static int vm_object_page_remove_callback(vm_page_t p, void *data);
1507 vm_object_page_remove(vm_object_t object, vm_pindex_t start, vm_pindex_t end,
1508 boolean_t clean_only)
1510 struct rb_vm_page_scan_info info;
1514 * Degenerate cases and assertions
1516 if (object == NULL || object->resident_page_count == 0)
1518 KASSERT(object->type != OBJT_PHYS,
1519 ("attempt to remove pages from a physical object"));
1522 * Indicate that paging is occuring on the object
1525 vm_object_pip_add(object, 1);
1528 * Figure out the actual removal range and whether we are removing
1529 * the entire contents of the object or not. If removing the entire
1530 * contents, be sure to get all pages, even those that might be
1531 * beyond the end of the object.
1533 info.start_pindex = start;
1535 info.end_pindex = (vm_pindex_t)-1;
1537 info.end_pindex = end - 1;
1538 info.limit = clean_only;
1539 all = (start == 0 && info.end_pindex >= object->size - 1);
1542 * Loop until we are sure we have gotten them all.
1546 vm_page_rb_tree_RB_SCAN(&object->rb_memq, rb_vm_page_scancmp,
1547 vm_object_page_remove_callback, &info);
1548 } while (info.error);
1553 vm_object_pip_wakeup(object);
1558 vm_object_page_remove_callback(vm_page_t p, void *data)
1560 struct rb_vm_page_scan_info *info = data;
1563 * Wired pages cannot be destroyed, but they can be invalidated
1564 * and we do so if clean_only (limit) is not set.
1566 if (p->wire_count != 0) {
1567 vm_page_protect(p, VM_PROT_NONE);
1568 if (info->limit == 0)
1574 * The busy flags are only cleared at
1575 * interrupt -- minimize the spl transitions
1578 if (vm_page_sleep_busy(p, TRUE, "vmopar")) {
1584 * limit is our clean_only flag. If set and the page is dirty, do
1587 if (info->limit && p->valid) {
1588 vm_page_test_dirty(p);
1589 if (p->valid & p->dirty)
1597 vm_page_protect(p, VM_PROT_NONE);
1603 * Routine: vm_object_coalesce
1604 * Function: Coalesces two objects backing up adjoining
1605 * regions of memory into a single object.
1607 * returns TRUE if objects were combined.
1609 * NOTE: Only works at the moment if the second object is NULL -
1610 * if it's not, which object do we lock first?
1613 * prev_object First object to coalesce
1614 * prev_offset Offset into prev_object
1615 * next_object Second object into coalesce
1616 * next_offset Offset into next_object
1618 * prev_size Size of reference to prev_object
1619 * next_size Size of reference to next_object
1622 * The object must *not* be locked.
1625 vm_object_coalesce(vm_object_t prev_object, vm_pindex_t prev_pindex,
1626 vm_size_t prev_size, vm_size_t next_size)
1628 vm_pindex_t next_pindex;
1630 if (prev_object == NULL) {
1634 if (prev_object->type != OBJT_DEFAULT &&
1635 prev_object->type != OBJT_SWAP) {
1640 * Try to collapse the object first
1642 vm_object_collapse(prev_object);
1645 * Can't coalesce if: . more than one reference . paged out . shadows
1646 * another object . has a copy elsewhere (any of which mean that the
1647 * pages not mapped to prev_entry may be in use anyway)
1650 if (prev_object->backing_object != NULL) {
1654 prev_size >>= PAGE_SHIFT;
1655 next_size >>= PAGE_SHIFT;
1656 next_pindex = prev_pindex + prev_size;
1658 if ((prev_object->ref_count > 1) &&
1659 (prev_object->size != next_pindex)) {
1664 * Remove any pages that may still be in the object from a previous
1667 if (next_pindex < prev_object->size) {
1668 vm_object_page_remove(prev_object,
1670 next_pindex + next_size, FALSE);
1671 if (prev_object->type == OBJT_SWAP)
1672 swap_pager_freespace(prev_object,
1673 next_pindex, next_size);
1677 * Extend the object if necessary.
1679 if (next_pindex + next_size > prev_object->size)
1680 prev_object->size = next_pindex + next_size;
1686 vm_object_set_writeable_dirty(vm_object_t object)
1690 vm_object_set_flag(object, OBJ_WRITEABLE|OBJ_MIGHTBEDIRTY);
1691 if (object->type == OBJT_VNODE &&
1692 (vp = (struct vnode *)object->handle) != NULL) {
1693 if ((vp->v_flag & VOBJDIRTY) == 0) {
1694 vsetflags(vp, VOBJDIRTY);
1701 #include "opt_ddb.h"
1703 #include <sys/kernel.h>
1705 #include <sys/cons.h>
1707 #include <ddb/ddb.h>
1709 static int _vm_object_in_map (vm_map_t map, vm_object_t object,
1710 vm_map_entry_t entry);
1711 static int vm_object_in_map (vm_object_t object);
1714 _vm_object_in_map(vm_map_t map, vm_object_t object, vm_map_entry_t entry)
1717 vm_map_entry_t tmpe;
1724 tmpe = map->header.next;
1725 entcount = map->nentries;
1726 while (entcount-- && (tmpe != &map->header)) {
1727 if( _vm_object_in_map(map, object, tmpe)) {
1734 switch(entry->maptype) {
1735 case VM_MAPTYPE_SUBMAP:
1736 tmpm = entry->object.sub_map;
1737 tmpe = tmpm->header.next;
1738 entcount = tmpm->nentries;
1739 while (entcount-- && tmpe != &tmpm->header) {
1740 if( _vm_object_in_map(tmpm, object, tmpe)) {
1746 case VM_MAPTYPE_NORMAL:
1747 case VM_MAPTYPE_VPAGETABLE:
1748 obj = entry->object.vm_object;
1752 obj = obj->backing_object;
1761 static int vm_object_in_map_callback(struct proc *p, void *data);
1763 struct vm_object_in_map_info {
1769 vm_object_in_map(vm_object_t object)
1771 struct vm_object_in_map_info info;
1774 info.object = object;
1776 allproc_scan(vm_object_in_map_callback, &info);
1779 if( _vm_object_in_map( kernel_map, object, 0))
1781 if( _vm_object_in_map( pager_map, object, 0))
1783 if( _vm_object_in_map( buffer_map, object, 0))
1789 vm_object_in_map_callback(struct proc *p, void *data)
1791 struct vm_object_in_map_info *info = data;
1794 if (_vm_object_in_map(&p->p_vmspace->vm_map, info->object, 0)) {
1802 DB_SHOW_COMMAND(vmochk, vm_object_check)
1807 * make sure that internal objs are in a map somewhere
1808 * and none have zero ref counts.
1810 for (object = TAILQ_FIRST(&vm_object_list);
1812 object = TAILQ_NEXT(object, object_list)) {
1813 if (object->handle == NULL &&
1814 (object->type == OBJT_DEFAULT || object->type == OBJT_SWAP)) {
1815 if (object->ref_count == 0) {
1816 db_printf("vmochk: internal obj has zero ref count: %ld\n",
1817 (long)object->size);
1819 if (!vm_object_in_map(object)) {
1821 "vmochk: internal obj is not in a map: "
1822 "ref: %d, size: %lu: 0x%lx, backing_object: %p\n",
1823 object->ref_count, (u_long)object->size,
1824 (u_long)object->size,
1825 (void *)object->backing_object);
1832 * vm_object_print: [ debug ]
1834 DB_SHOW_COMMAND(object, vm_object_print_static)
1836 /* XXX convert args. */
1837 vm_object_t object = (vm_object_t)addr;
1838 boolean_t full = have_addr;
1842 /* XXX count is an (unused) arg. Avoid shadowing it. */
1843 #define count was_count
1851 "Object %p: type=%d, size=0x%lx, res=%d, ref=%d, flags=0x%x\n",
1852 object, (int)object->type, (u_long)object->size,
1853 object->resident_page_count, object->ref_count, object->flags);
1855 * XXX no %qd in kernel. Truncate object->backing_object_offset.
1857 db_iprintf(" sref=%d, backing_object(%d)=(%p)+0x%lx\n",
1858 object->shadow_count,
1859 object->backing_object ? object->backing_object->ref_count : 0,
1860 object->backing_object, (long)object->backing_object_offset);
1867 RB_FOREACH(p, vm_page_rb_tree, &object->rb_memq) {
1869 db_iprintf("memory:=");
1870 else if (count == 6) {
1878 db_printf("(off=0x%lx,page=0x%lx)",
1879 (u_long) p->pindex, (u_long) VM_PAGE_TO_PHYS(p));
1889 /* XXX need this non-static entry for calling from vm_map_print. */
1891 vm_object_print(/* db_expr_t */ long addr,
1892 boolean_t have_addr,
1893 /* db_expr_t */ long count,
1896 vm_object_print_static(addr, have_addr, count, modif);
1899 DB_SHOW_COMMAND(vmopag, vm_object_print_pages)
1904 for (object = TAILQ_FIRST(&vm_object_list);
1906 object = TAILQ_NEXT(object, object_list)) {
1907 vm_pindex_t idx, fidx;
1909 vm_paddr_t pa = -1, padiff;
1913 db_printf("new object: %p\n", (void *)object);
1923 osize = object->size;
1926 for (idx = 0; idx < osize; idx++) {
1927 m = vm_page_lookup(object, idx);
1930 db_printf(" index(%ld)run(%d)pa(0x%lx)\n",
1931 (long)fidx, rcount, (long)pa);
1946 (VM_PAGE_TO_PHYS(m) == pa + rcount * PAGE_SIZE)) {
1951 padiff = pa + rcount * PAGE_SIZE - VM_PAGE_TO_PHYS(m);
1952 padiff >>= PAGE_SHIFT;
1953 padiff &= PQ_L2_MASK;
1955 pa = VM_PAGE_TO_PHYS(m) - rcount * PAGE_SIZE;
1959 db_printf(" index(%ld)run(%d)pa(0x%lx)",
1960 (long)fidx, rcount, (long)pa);
1961 db_printf("pd(%ld)\n", (long)padiff);
1971 pa = VM_PAGE_TO_PHYS(m);
1975 db_printf(" index(%ld)run(%d)pa(0x%lx)\n",
1976 (long)fidx, rcount, (long)pa);