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 1.17 2004/07/28 20:40:35 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 #define MSYNC_FLUSH_HARDSEQ 0x01
98 #define MSYNC_FLUSH_SOFTSEQ 0x02
100 static int msync_flush_flags = MSYNC_FLUSH_HARDSEQ | MSYNC_FLUSH_SOFTSEQ;
101 SYSCTL_INT(_vm, OID_AUTO, msync_flush_flags,
102 CTLFLAG_RW, &msync_flush_flags, 0, "");
104 static void vm_object_qcollapse (vm_object_t object);
105 static int vm_object_page_collect_flush(vm_object_t object, vm_page_t p, int curgeneration, int pagerflags);
108 * Virtual memory objects maintain the actual data
109 * associated with allocated virtual memory. A given
110 * page of memory exists within exactly one object.
112 * An object is only deallocated when all "references"
113 * are given up. Only one "reference" to a given
114 * region of an object should be writeable.
116 * Associated with each object is a list of all resident
117 * memory pages belonging to that object; this list is
118 * maintained by the "vm_page" module, and locked by the object's
121 * Each object also records a "pager" routine which is
122 * used to retrieve (and store) pages to the proper backing
123 * storage. In addition, objects may be backed by other
124 * objects from which they were virtual-copied.
126 * The only items within the object structure which are
127 * modified after time of creation are:
128 * reference count locked by object's lock
129 * pager routine locked by object's lock
133 struct object_q vm_object_list;
134 static struct lwkt_token vm_object_list_token;
135 static long vm_object_count; /* count of all objects */
136 vm_object_t kernel_object;
137 vm_object_t kmem_object;
138 static struct vm_object kernel_object_store;
139 static struct vm_object kmem_object_store;
140 extern int vm_pageout_page_count;
142 static long object_collapses;
143 static long object_bypasses;
144 static int next_index;
145 static vm_zone_t obj_zone;
146 static struct vm_zone obj_zone_store;
147 static int object_hash_rand;
148 #define VM_OBJECTS_INIT 256
149 static struct vm_object vm_objects_init[VM_OBJECTS_INIT];
152 _vm_object_allocate(objtype_t type, vm_size_t size, vm_object_t object)
155 TAILQ_INIT(&object->memq);
156 LIST_INIT(&object->shadow_head);
160 object->ref_count = 1;
162 if ((object->type == OBJT_DEFAULT) || (object->type == OBJT_SWAP))
163 vm_object_set_flag(object, OBJ_ONEMAPPING);
164 object->paging_in_progress = 0;
165 object->resident_page_count = 0;
166 object->shadow_count = 0;
167 object->pg_color = next_index;
168 if ( size > (PQ_L2_SIZE / 3 + PQ_PRIME1))
169 incr = PQ_L2_SIZE / 3 + PQ_PRIME1;
172 next_index = (next_index + incr) & PQ_L2_MASK;
173 object->handle = NULL;
174 object->backing_object = NULL;
175 object->backing_object_offset = (vm_ooffset_t) 0;
177 * Try to generate a number that will spread objects out in the
178 * hash table. We 'wipe' new objects across the hash in 128 page
179 * increments plus 1 more to offset it a little more by the time
182 object->hash_rand = object_hash_rand - 129;
184 object->generation++;
186 TAILQ_INSERT_TAIL(&vm_object_list, object, object_list);
188 object_hash_rand = object->hash_rand;
194 * Initialize the VM objects module.
199 TAILQ_INIT(&vm_object_list);
200 lwkt_token_init(&vm_object_list_token);
203 kernel_object = &kernel_object_store;
204 _vm_object_allocate(OBJT_DEFAULT, OFF_TO_IDX(VM_MAX_KERNEL_ADDRESS - VM_MIN_KERNEL_ADDRESS),
207 kmem_object = &kmem_object_store;
208 _vm_object_allocate(OBJT_DEFAULT, OFF_TO_IDX(VM_MAX_KERNEL_ADDRESS - VM_MIN_KERNEL_ADDRESS),
211 obj_zone = &obj_zone_store;
212 zbootinit(obj_zone, "VM OBJECT", sizeof (struct vm_object),
213 vm_objects_init, VM_OBJECTS_INIT);
217 vm_object_init2(void)
219 zinitna(obj_zone, NULL, NULL, 0, 0, ZONE_PANICFAIL, 1);
223 * vm_object_allocate:
225 * Returns a new object with the given size.
229 vm_object_allocate(objtype_t type, vm_size_t size)
233 result = (vm_object_t) zalloc(obj_zone);
235 _vm_object_allocate(type, size, result);
242 * vm_object_reference:
244 * Gets another reference to the given object.
247 vm_object_reference(vm_object_t object)
253 /* object can be re-referenced during final cleaning */
254 KASSERT(!(object->flags & OBJ_DEAD),
255 ("vm_object_reference: attempting to reference dead obj"));
259 if (object->type == OBJT_VNODE) {
260 while (vget((struct vnode *) object->handle, NULL,
261 LK_RETRY|LK_NOOBJ, curthread)) {
262 printf("vm_object_reference: delay in getting object\n");
268 vm_object_vndeallocate(vm_object_t object)
270 struct vnode *vp = (struct vnode *) object->handle;
272 KASSERT(object->type == OBJT_VNODE,
273 ("vm_object_vndeallocate: not a vnode object"));
274 KASSERT(vp != NULL, ("vm_object_vndeallocate: missing vp"));
276 if (object->ref_count == 0) {
277 vprint("vm_object_vndeallocate", vp);
278 panic("vm_object_vndeallocate: bad object reference count");
283 if (object->ref_count == 0) {
284 vp->v_flag &= ~VTEXT;
285 vm_object_clear_flag(object, OBJ_OPT);
291 * vm_object_deallocate:
293 * Release a reference to the specified object,
294 * gained either through a vm_object_allocate
295 * or a vm_object_reference call. When all references
296 * are gone, storage associated with this object
297 * may be relinquished.
299 * No object may be locked.
302 vm_object_deallocate(vm_object_t object)
306 while (object != NULL) {
308 if (object->type == OBJT_VNODE) {
309 vm_object_vndeallocate(object);
313 if (object->ref_count == 0) {
314 panic("vm_object_deallocate: object deallocated too many times: %d", object->type);
315 } else if (object->ref_count > 2) {
321 * Here on ref_count of one or two, which are special cases for
324 if ((object->ref_count == 2) && (object->shadow_count == 0)) {
325 vm_object_set_flag(object, OBJ_ONEMAPPING);
328 } else if ((object->ref_count == 2) && (object->shadow_count == 1)) {
330 if ((object->handle == NULL) &&
331 (object->type == OBJT_DEFAULT ||
332 object->type == OBJT_SWAP)) {
335 robject = LIST_FIRST(&object->shadow_head);
336 KASSERT(robject != NULL,
337 ("vm_object_deallocate: ref_count: %d, shadow_count: %d",
339 object->shadow_count));
340 if ((robject->handle == NULL) &&
341 (robject->type == OBJT_DEFAULT ||
342 robject->type == OBJT_SWAP)) {
344 robject->ref_count++;
347 robject->paging_in_progress ||
348 object->paging_in_progress
350 vm_object_pip_sleep(robject, "objde1");
351 vm_object_pip_sleep(object, "objde2");
354 if (robject->ref_count == 1) {
355 robject->ref_count--;
361 vm_object_collapse(object);
370 if (object->ref_count != 0)
376 temp = object->backing_object;
378 LIST_REMOVE(object, shadow_list);
379 temp->shadow_count--;
380 if (temp->ref_count == 0)
381 vm_object_clear_flag(temp, OBJ_OPT);
383 object->backing_object = NULL;
387 * Don't double-terminate, we could be in a termination
388 * recursion due to the terminate having to sync data
391 if ((object->flags & OBJ_DEAD) == 0)
392 vm_object_terminate(object);
398 * vm_object_terminate actually destroys the specified object, freeing
399 * up all previously used resources.
401 * The object must be locked.
402 * This routine may block.
405 vm_object_terminate(vm_object_t object)
412 * Make sure no one uses us.
414 vm_object_set_flag(object, OBJ_DEAD);
417 * wait for the pageout daemon to be done with the object
419 vm_object_pip_wait(object, "objtrm");
421 KASSERT(!object->paging_in_progress,
422 ("vm_object_terminate: pageout in progress"));
425 * Clean and free the pages, as appropriate. All references to the
426 * object are gone, so we don't need to lock it.
428 if (object->type == OBJT_VNODE) {
432 * Freeze optimized copies.
434 vm_freeze_copyopts(object, 0, object->size);
437 * Clean pages and flush buffers.
439 vm_object_page_clean(object, 0, 0, OBJPC_SYNC);
441 vp = (struct vnode *) object->handle;
442 vinvalbuf(vp, V_SAVE, NULL, 0, 0);
446 * Wait for any I/O to complete, after which there had better not
447 * be any references left on the object.
449 vm_object_pip_wait(object, "objtrm");
451 if (object->ref_count != 0)
452 panic("vm_object_terminate: object with references, ref_count=%d", object->ref_count);
455 * Now free any remaining pages. For internal objects, this also
456 * removes them from paging queues. Don't free wired pages, just
457 * remove them from the object.
460 while ((p = TAILQ_FIRST(&object->memq)) != NULL) {
461 if (p->busy || (p->flags & PG_BUSY))
462 panic("vm_object_terminate: freeing busy page %p", p);
463 if (p->wire_count == 0) {
466 mycpu->gd_cnt.v_pfree++;
475 * Let the pager know object is dead.
477 vm_pager_deallocate(object);
480 * Remove the object from the global object list.
482 lwkt_gettoken(&ilock, &vm_object_list_token);
483 TAILQ_REMOVE(&vm_object_list, object, object_list);
484 lwkt_reltoken(&ilock);
489 * Free the space for the object.
491 zfree(obj_zone, object);
495 * vm_object_page_clean
497 * Clean all dirty pages in the specified range of object. Leaves page
498 * on whatever queue it is currently on. If NOSYNC is set then do not
499 * write out pages with PG_NOSYNC set (originally comes from MAP_NOSYNC),
500 * leaving the object dirty.
502 * When stuffing pages asynchronously, allow clustering. XXX we need a
503 * synchronous clustering mode implementation.
505 * Odd semantics: if start == end, we clean everything.
509 vm_object_page_clean(vm_object_t object, vm_pindex_t start, vm_pindex_t end,
513 vm_offset_t tstart, tend;
522 if (object->type != OBJT_VNODE ||
523 (object->flags & OBJ_MIGHTBEDIRTY) == 0)
526 pagerflags = (flags & (OBJPC_SYNC | OBJPC_INVAL)) ? VM_PAGER_PUT_SYNC : VM_PAGER_CLUSTER_OK;
527 pagerflags |= (flags & OBJPC_INVAL) ? VM_PAGER_PUT_INVAL : 0;
531 vm_object_set_flag(object, OBJ_CLEANING);
534 * Handle 'entire object' case
544 * If the caller is smart and only msync()s a range he knows is
545 * dirty, we may be able to avoid an object scan. This results in
546 * a phenominal improvement in performance. We cannot do this
547 * as a matter of course because the object may be huge - e.g.
548 * the size might be in the gigabytes or terrabytes.
550 if (msync_flush_flags & MSYNC_FLUSH_HARDSEQ) {
555 scanreset = object->resident_page_count / EASY_SCAN_FACTOR;
558 pagerflags |= VM_PAGER_IGNORE_CLEANCHK;
560 scanlimit = scanreset;
564 * spl protection is required despite the obj generation
565 * tracking because we cannot safely call vm_page_test_dirty()
566 * or avoid page field tests against an interrupt unbusy/free
567 * race that might occur prior to the busy check in
568 * vm_object_page_collect_flush().
571 while (tscan < tend) {
572 curgeneration = object->generation;
573 p = vm_page_lookup(object, tscan);
574 if (p == NULL || p->valid == 0 ||
575 (p->queue - p->pc) == PQ_CACHE) {
576 if (--scanlimit == 0)
581 vm_page_test_dirty(p);
582 if ((p->dirty & p->valid) == 0) {
583 if (--scanlimit == 0)
589 * If we have been asked to skip nosync pages and
590 * this is a nosync page, we can't continue.
592 if ((flags & OBJPC_NOSYNC) && (p->flags & PG_NOSYNC)) {
593 if (--scanlimit == 0)
598 scanlimit = scanreset;
601 * This returns 0 if it was unable to busy the first
602 * page (i.e. had to sleep).
604 tscan += vm_object_page_collect_flush(object, p,
605 curgeneration, pagerflags);
610 * If everything was dirty and we flushed it successfully,
611 * and the requested range is not the entire object, we
612 * don't have to mess with CLEANCHK or MIGHTBEDIRTY and can
613 * return immediately.
615 if (tscan >= tend && (tstart || tend < object->size)) {
616 vm_object_clear_flag(object, OBJ_CLEANING);
619 pagerflags &= ~VM_PAGER_IGNORE_CLEANCHK;
623 * Generally set CLEANCHK interlock and make the page read-only so
624 * we can then clear the object flags.
626 * However, if this is a nosync mmap then the object is likely to
627 * stay dirty so do not mess with the page and do not clear the
630 * spl protection is required because an interrupt can remove page
636 for (p = TAILQ_FIRST(&object->memq); p; p = TAILQ_NEXT(p, listq)) {
637 vm_page_flag_set(p, PG_CLEANCHK);
638 if ((flags & OBJPC_NOSYNC) && (p->flags & PG_NOSYNC))
641 vm_page_protect(p, VM_PROT_READ);
645 if (clearobjflags && (tstart == 0) && (tend == object->size)) {
648 vm_object_clear_flag(object, OBJ_WRITEABLE|OBJ_MIGHTBEDIRTY);
649 if (object->type == OBJT_VNODE &&
650 (vp = (struct vnode *)object->handle) != NULL) {
651 if (vp->v_flag & VOBJDIRTY) {
652 lwkt_gettoken(&vlock, vp->v_interlock);
653 vp->v_flag &= ~VOBJDIRTY;
654 lwkt_reltoken(&vlock);
660 * spl protection is required both to avoid an interrupt unbusy/free
661 * race against a vm_page_lookup(), and also to ensure that the
662 * memq is consistent. We do not want a busy page to be ripped out
667 splx(s); /* give interrupts a chance */
669 curgeneration = object->generation;
671 for (p = TAILQ_FIRST(&object->memq); p; p = np) {
674 np = TAILQ_NEXT(p, listq);
678 if (((p->flags & PG_CLEANCHK) == 0) ||
679 (pi < tstart) || (pi >= tend) ||
681 ((p->queue - p->pc) == PQ_CACHE)) {
682 vm_page_flag_clear(p, PG_CLEANCHK);
686 vm_page_test_dirty(p);
687 if ((p->dirty & p->valid) == 0) {
688 vm_page_flag_clear(p, PG_CLEANCHK);
693 * If we have been asked to skip nosync pages and this is a
694 * nosync page, skip it. Note that the object flags were
695 * not cleared in this case so we do not have to set them.
697 if ((flags & OBJPC_NOSYNC) && (p->flags & PG_NOSYNC)) {
698 vm_page_flag_clear(p, PG_CLEANCHK);
702 n = vm_object_page_collect_flush(object, p,
703 curgeneration, pagerflags);
706 if (object->generation != curgeneration)
710 * Try to optimize the next page. If we can't we pick up
711 * our (random) scan where we left off.
713 if (msync_flush_flags & MSYNC_FLUSH_SOFTSEQ) {
714 if ((p = vm_page_lookup(object, pi + n)) != NULL)
721 VOP_FSYNC(vp, NULL, (pagerflags & VM_PAGER_PUT_SYNC)?MNT_WAIT:0, curproc);
724 vm_object_clear_flag(object, OBJ_CLEANING);
729 * This routine must be called at splvm() to properly avoid an interrupt
730 * unbusy/free race that can occur prior to the busy check.
732 * Using the object generation number here to detect page ripout is not
733 * the best idea in the world. XXX
735 * NOTE: we operate under the assumption that a page found to not be busy
736 * will not be ripped out from under us by an interrupt. XXX we should
737 * recode this to explicitly busy the pages.
740 vm_object_page_collect_flush(vm_object_t object, vm_page_t p, int curgeneration, int pagerflags)
748 vm_page_t maf[vm_pageout_page_count];
749 vm_page_t mab[vm_pageout_page_count];
750 vm_page_t ma[vm_pageout_page_count];
753 while (vm_page_sleep_busy(p, TRUE, "vpcwai")) {
754 if (object->generation != curgeneration) {
760 for(i = 1; i < vm_pageout_page_count; i++) {
763 if ((tp = vm_page_lookup(object, pi + i)) != NULL) {
764 if ((tp->flags & PG_BUSY) ||
765 ((pagerflags & VM_PAGER_IGNORE_CLEANCHK) == 0 &&
766 (tp->flags & PG_CLEANCHK) == 0) ||
769 if((tp->queue - tp->pc) == PQ_CACHE) {
770 vm_page_flag_clear(tp, PG_CLEANCHK);
773 vm_page_test_dirty(tp);
774 if ((tp->dirty & tp->valid) == 0) {
775 vm_page_flag_clear(tp, PG_CLEANCHK);
786 chkb = vm_pageout_page_count - maxf;
788 for(i = 1; i < chkb;i++) {
791 if ((tp = vm_page_lookup(object, pi - i)) != NULL) {
792 if ((tp->flags & PG_BUSY) ||
793 ((pagerflags & VM_PAGER_IGNORE_CLEANCHK) == 0 &&
794 (tp->flags & PG_CLEANCHK) == 0) ||
797 if((tp->queue - tp->pc) == PQ_CACHE) {
798 vm_page_flag_clear(tp, PG_CLEANCHK);
801 vm_page_test_dirty(tp);
802 if ((tp->dirty & tp->valid) == 0) {
803 vm_page_flag_clear(tp, PG_CLEANCHK);
814 for(i = 0; i < maxb; i++) {
815 int index = (maxb - i) - 1;
817 vm_page_flag_clear(ma[index], PG_CLEANCHK);
819 vm_page_flag_clear(p, PG_CLEANCHK);
821 for(i = 0; i < maxf; i++) {
822 int index = (maxb + i) + 1;
824 vm_page_flag_clear(ma[index], PG_CLEANCHK);
826 runlen = maxb + maxf + 1;
828 vm_pageout_flush(ma, runlen, pagerflags);
829 for (i = 0; i < runlen; i++) {
830 if (ma[i]->valid & ma[i]->dirty) {
831 vm_page_protect(ma[i], VM_PROT_READ);
832 vm_page_flag_set(ma[i], PG_CLEANCHK);
835 * maxf will end up being the actual number of pages
836 * we wrote out contiguously, non-inclusive of the
837 * first page. We do not count look-behind pages.
839 if (i >= maxb + 1 && (maxf > i - maxb - 1))
847 /* XXX I cannot tell if this should be an exported symbol */
849 * vm_object_deactivate_pages
851 * Deactivate all pages in the specified object. (Keep its pages
852 * in memory even though it is no longer referenced.)
854 * The object must be locked.
857 vm_object_deactivate_pages(vm_object_t object)
863 for (p = TAILQ_FIRST(&object->memq); p != NULL; p = next) {
864 next = TAILQ_NEXT(p, listq);
865 vm_page_deactivate(p);
872 * Same as vm_object_pmap_copy, except range checking really
873 * works, and is meant for small sections of an object.
875 * This code protects resident pages by making them read-only
876 * and is typically called on a fork or split when a page
877 * is converted to copy-on-write.
879 * NOTE: If the page is already at VM_PROT_NONE, calling
880 * vm_page_protect will have no effect.
883 vm_object_pmap_copy_1(vm_object_t object, vm_pindex_t start, vm_pindex_t end)
889 if (object == NULL || (object->flags & OBJ_WRITEABLE) == 0)
893 * spl protection needed to prevent races between the lookup,
894 * an interrupt unbusy/free, and our protect call.
897 for (idx = start; idx < end; idx++) {
898 p = vm_page_lookup(object, idx);
901 vm_page_protect(p, VM_PROT_READ);
907 * vm_object_pmap_remove:
909 * Removes all physical pages in the specified
910 * object range from all physical maps.
912 * The object must *not* be locked.
915 vm_object_pmap_remove(vm_object_t object, vm_pindex_t start, vm_pindex_t end)
924 * spl protection is required because an interrupt can unbusy/free
928 for (p = TAILQ_FIRST(&object->memq);
930 p = TAILQ_NEXT(p, listq)
932 if (p->pindex >= start && p->pindex < end)
933 vm_page_protect(p, VM_PROT_NONE);
936 if ((start == 0) && (object->size == end))
937 vm_object_clear_flag(object, OBJ_WRITEABLE);
943 * Implements the madvise function at the object/page level.
945 * MADV_WILLNEED (any object)
947 * Activate the specified pages if they are resident.
949 * MADV_DONTNEED (any object)
951 * Deactivate the specified pages if they are resident.
953 * MADV_FREE (OBJT_DEFAULT/OBJT_SWAP objects,
954 * OBJ_ONEMAPPING only)
956 * Deactivate and clean the specified pages if they are
957 * resident. This permits the process to reuse the pages
958 * without faulting or the kernel to reclaim the pages
962 vm_object_madvise(vm_object_t object, vm_pindex_t pindex, int count, int advise)
964 vm_pindex_t end, tpindex;
972 end = pindex + count;
975 * Locate and adjust resident pages
978 for (; pindex < end; pindex += 1) {
984 * MADV_FREE only operates on OBJT_DEFAULT or OBJT_SWAP pages
985 * and those pages must be OBJ_ONEMAPPING.
987 if (advise == MADV_FREE) {
988 if ((tobject->type != OBJT_DEFAULT &&
989 tobject->type != OBJT_SWAP) ||
990 (tobject->flags & OBJ_ONEMAPPING) == 0) {
996 * spl protection is required to avoid a race between the
997 * lookup, an interrupt unbusy/free, and our busy check.
1001 m = vm_page_lookup(tobject, tpindex);
1005 * There may be swap even if there is no backing page
1007 if (advise == MADV_FREE && tobject->type == OBJT_SWAP)
1008 swap_pager_freespace(tobject, tpindex, 1);
1014 if (tobject->backing_object == NULL)
1016 tpindex += OFF_TO_IDX(tobject->backing_object_offset);
1017 tobject = tobject->backing_object;
1022 * If the page is busy or not in a normal active state,
1023 * we skip it. If the page is not managed there are no
1024 * page queues to mess with. Things can break if we mess
1025 * with pages in any of the below states.
1030 (m->flags & PG_UNMANAGED) ||
1031 m->valid != VM_PAGE_BITS_ALL
1037 if (vm_page_sleep_busy(m, TRUE, "madvpo")) {
1044 * Theoretically once a page is known not to be busy, an
1045 * interrupt cannot come along and rip it out from under us.
1048 if (advise == MADV_WILLNEED) {
1049 vm_page_activate(m);
1050 } else if (advise == MADV_DONTNEED) {
1051 vm_page_dontneed(m);
1052 } else if (advise == MADV_FREE) {
1054 * Mark the page clean. This will allow the page
1055 * to be freed up by the system. However, such pages
1056 * are often reused quickly by malloc()/free()
1057 * so we do not do anything that would cause
1058 * a page fault if we can help it.
1060 * Specifically, we do not try to actually free
1061 * the page now nor do we try to put it in the
1062 * cache (which would cause a page fault on reuse).
1064 * But we do make the page is freeable as we
1065 * can without actually taking the step of unmapping
1068 pmap_clear_modify(m);
1071 vm_page_dontneed(m);
1072 if (tobject->type == OBJT_SWAP)
1073 swap_pager_freespace(tobject, tpindex, 1);
1081 * Create a new object which is backed by the
1082 * specified existing object range. The source
1083 * object reference is deallocated.
1085 * The new object and offset into that object
1086 * are returned in the source parameters.
1090 vm_object_shadow(vm_object_t *object, /* IN/OUT */
1091 vm_ooffset_t *offset, /* IN/OUT */
1100 * Don't create the new object if the old object isn't shared.
1103 if (source != NULL &&
1104 source->ref_count == 1 &&
1105 source->handle == NULL &&
1106 (source->type == OBJT_DEFAULT ||
1107 source->type == OBJT_SWAP))
1111 * Allocate a new object with the given length
1114 if ((result = vm_object_allocate(OBJT_DEFAULT, length)) == NULL)
1115 panic("vm_object_shadow: no object for shadowing");
1118 * The new object shadows the source object, adding a reference to it.
1119 * Our caller changes his reference to point to the new object,
1120 * removing a reference to the source object. Net result: no change
1121 * of reference count.
1123 * Try to optimize the result object's page color when shadowing
1124 * in order to maintain page coloring consistency in the combined
1127 result->backing_object = source;
1129 LIST_INSERT_HEAD(&source->shadow_head, result, shadow_list);
1130 source->shadow_count++;
1131 source->generation++;
1132 result->pg_color = (source->pg_color + OFF_TO_IDX(*offset)) & PQ_L2_MASK;
1136 * Store the offset into the source object, and fix up the offset into
1140 result->backing_object_offset = *offset;
1143 * Return the new things
1150 #define OBSC_TEST_ALL_SHADOWED 0x0001
1151 #define OBSC_COLLAPSE_NOWAIT 0x0002
1152 #define OBSC_COLLAPSE_WAIT 0x0004
1155 vm_object_backing_scan(vm_object_t object, int op)
1160 vm_object_t backing_object;
1161 vm_pindex_t backing_offset_index;
1164 * spl protection is required to avoid races between the memq/lookup,
1165 * an interrupt doing an unbusy/free, and our busy check. Amoung
1170 backing_object = object->backing_object;
1171 backing_offset_index = OFF_TO_IDX(object->backing_object_offset);
1174 * Initial conditions
1177 if (op & OBSC_TEST_ALL_SHADOWED) {
1179 * We do not want to have to test for the existence of
1180 * swap pages in the backing object. XXX but with the
1181 * new swapper this would be pretty easy to do.
1183 * XXX what about anonymous MAP_SHARED memory that hasn't
1184 * been ZFOD faulted yet? If we do not test for this, the
1185 * shadow test may succeed! XXX
1187 if (backing_object->type != OBJT_DEFAULT) {
1192 if (op & OBSC_COLLAPSE_WAIT) {
1193 vm_object_set_flag(backing_object, OBJ_DEAD);
1200 p = TAILQ_FIRST(&backing_object->memq);
1202 vm_page_t next = TAILQ_NEXT(p, listq);
1203 vm_pindex_t new_pindex = p->pindex - backing_offset_index;
1205 if (op & OBSC_TEST_ALL_SHADOWED) {
1209 * Ignore pages outside the parent object's range
1210 * and outside the parent object's mapping of the
1213 * note that we do not busy the backing object's
1218 p->pindex < backing_offset_index ||
1219 new_pindex >= object->size
1226 * See if the parent has the page or if the parent's
1227 * object pager has the page. If the parent has the
1228 * page but the page is not valid, the parent's
1229 * object pager must have the page.
1231 * If this fails, the parent does not completely shadow
1232 * the object and we might as well give up now.
1235 pp = vm_page_lookup(object, new_pindex);
1237 (pp == NULL || pp->valid == 0) &&
1238 !vm_pager_has_page(object, new_pindex, NULL, NULL)
1246 * Check for busy page
1249 if (op & (OBSC_COLLAPSE_WAIT | OBSC_COLLAPSE_NOWAIT)) {
1252 if (op & OBSC_COLLAPSE_NOWAIT) {
1254 (p->flags & PG_BUSY) ||
1263 } else if (op & OBSC_COLLAPSE_WAIT) {
1264 if (vm_page_sleep_busy(p, TRUE, "vmocol")) {
1266 * If we slept, anything could have
1267 * happened. Since the object is
1268 * marked dead, the backing offset
1269 * should not have changed so we
1270 * just restart our scan.
1272 p = TAILQ_FIRST(&backing_object->memq);
1283 p->object == backing_object,
1284 ("vm_object_qcollapse(): object mismatch")
1288 * Destroy any associated swap
1290 if (backing_object->type == OBJT_SWAP) {
1291 swap_pager_freespace(
1299 p->pindex < backing_offset_index ||
1300 new_pindex >= object->size
1303 * Page is out of the parent object's range, we
1304 * can simply destroy it.
1306 vm_page_protect(p, VM_PROT_NONE);
1312 pp = vm_page_lookup(object, new_pindex);
1315 vm_pager_has_page(object, new_pindex, NULL, NULL)
1318 * page already exists in parent OR swap exists
1319 * for this location in the parent. Destroy
1320 * the original page from the backing object.
1322 * Leave the parent's page alone
1324 vm_page_protect(p, VM_PROT_NONE);
1331 * Page does not exist in parent, rename the
1332 * page from the backing object to the main object.
1334 * If the page was mapped to a process, it can remain
1335 * mapped through the rename.
1337 if ((p->queue - p->pc) == PQ_CACHE)
1338 vm_page_deactivate(p);
1340 vm_page_rename(p, object, new_pindex);
1341 /* page automatically made dirty by rename */
1351 * this version of collapse allows the operation to occur earlier and
1352 * when paging_in_progress is true for an object... This is not a complete
1353 * operation, but should plug 99.9% of the rest of the leaks.
1356 vm_object_qcollapse(vm_object_t object)
1358 vm_object_t backing_object = object->backing_object;
1360 if (backing_object->ref_count != 1)
1363 backing_object->ref_count += 2;
1365 vm_object_backing_scan(object, OBSC_COLLAPSE_NOWAIT);
1367 backing_object->ref_count -= 2;
1371 * vm_object_collapse:
1373 * Collapse an object with the object backing it.
1374 * Pages in the backing object are moved into the
1375 * parent, and the backing object is deallocated.
1378 vm_object_collapse(vm_object_t object)
1381 vm_object_t backing_object;
1384 * Verify that the conditions are right for collapse:
1386 * The object exists and the backing object exists.
1391 if ((backing_object = object->backing_object) == NULL)
1395 * we check the backing object first, because it is most likely
1398 if (backing_object->handle != NULL ||
1399 (backing_object->type != OBJT_DEFAULT &&
1400 backing_object->type != OBJT_SWAP) ||
1401 (backing_object->flags & OBJ_DEAD) ||
1402 object->handle != NULL ||
1403 (object->type != OBJT_DEFAULT &&
1404 object->type != OBJT_SWAP) ||
1405 (object->flags & OBJ_DEAD)) {
1410 object->paging_in_progress != 0 ||
1411 backing_object->paging_in_progress != 0
1413 vm_object_qcollapse(object);
1418 * We know that we can either collapse the backing object (if
1419 * the parent is the only reference to it) or (perhaps) have
1420 * the parent bypass the object if the parent happens to shadow
1421 * all the resident pages in the entire backing object.
1423 * This is ignoring pager-backed pages such as swap pages.
1424 * vm_object_backing_scan fails the shadowing test in this
1428 if (backing_object->ref_count == 1) {
1430 * If there is exactly one reference to the backing
1431 * object, we can collapse it into the parent.
1434 vm_object_backing_scan(object, OBSC_COLLAPSE_WAIT);
1437 * Move the pager from backing_object to object.
1440 if (backing_object->type == OBJT_SWAP) {
1441 vm_object_pip_add(backing_object, 1);
1444 * scrap the paging_offset junk and do a
1445 * discrete copy. This also removes major
1446 * assumptions about how the swap-pager
1447 * works from where it doesn't belong. The
1448 * new swapper is able to optimize the
1449 * destroy-source case.
1452 vm_object_pip_add(object, 1);
1456 OFF_TO_IDX(object->backing_object_offset), TRUE);
1457 vm_object_pip_wakeup(object);
1459 vm_object_pip_wakeup(backing_object);
1462 * Object now shadows whatever backing_object did.
1463 * Note that the reference to
1464 * backing_object->backing_object moves from within
1465 * backing_object to within object.
1468 LIST_REMOVE(object, shadow_list);
1469 object->backing_object->shadow_count--;
1470 object->backing_object->generation++;
1471 if (backing_object->backing_object) {
1472 LIST_REMOVE(backing_object, shadow_list);
1473 backing_object->backing_object->shadow_count--;
1474 backing_object->backing_object->generation++;
1476 object->backing_object = backing_object->backing_object;
1477 if (object->backing_object) {
1479 &object->backing_object->shadow_head,
1483 object->backing_object->shadow_count++;
1484 object->backing_object->generation++;
1487 object->backing_object_offset +=
1488 backing_object->backing_object_offset;
1491 * Discard backing_object.
1493 * Since the backing object has no pages, no pager left,
1494 * and no object references within it, all that is
1495 * necessary is to dispose of it.
1498 KASSERT(backing_object->ref_count == 1, ("backing_object %p was somehow re-referenced during collapse!", backing_object));
1499 KASSERT(TAILQ_FIRST(&backing_object->memq) == NULL, ("backing_object %p somehow has left over pages during collapse!", backing_object));
1507 zfree(obj_zone, backing_object);
1511 vm_object_t new_backing_object;
1514 * If we do not entirely shadow the backing object,
1515 * there is nothing we can do so we give up.
1518 if (vm_object_backing_scan(object, OBSC_TEST_ALL_SHADOWED) == 0) {
1523 * Make the parent shadow the next object in the
1524 * chain. Deallocating backing_object will not remove
1525 * it, since its reference count is at least 2.
1528 LIST_REMOVE(object, shadow_list);
1529 backing_object->shadow_count--;
1530 backing_object->generation++;
1532 new_backing_object = backing_object->backing_object;
1533 if ((object->backing_object = new_backing_object) != NULL) {
1534 vm_object_reference(new_backing_object);
1536 &new_backing_object->shadow_head,
1540 new_backing_object->shadow_count++;
1541 new_backing_object->generation++;
1542 object->backing_object_offset +=
1543 backing_object->backing_object_offset;
1547 * Drop the reference count on backing_object. Since
1548 * its ref_count was at least 2, it will not vanish;
1549 * so we don't need to call vm_object_deallocate, but
1552 vm_object_deallocate(backing_object);
1557 * Try again with this object's new backing object.
1563 * vm_object_page_remove: [internal]
1565 * Removes all physical pages in the specified
1566 * object range from the object's list of pages.
1569 vm_object_page_remove(vm_object_t object, vm_pindex_t start, vm_pindex_t end,
1570 boolean_t clean_only)
1577 if (object == NULL || object->resident_page_count == 0)
1580 all = ((end == 0) && (start == 0));
1583 * Since physically-backed objects do not use managed pages, we can't
1584 * remove pages from the object (we must instead remove the page
1585 * references, and then destroy the object).
1587 KASSERT(object->type != OBJT_PHYS,
1588 ("attempt to remove pages from a physical object"));
1591 * Indicating that the object is undergoing paging.
1593 * spl protection is required to avoid a race between the memq scan,
1594 * an interrupt unbusy/free, and the busy check.
1596 vm_object_pip_add(object, 1);
1600 if (all || size > object->resident_page_count / 4) {
1601 for (p = TAILQ_FIRST(&object->memq); p != NULL; p = next) {
1602 next = TAILQ_NEXT(p, listq);
1603 if (all || ((start <= p->pindex) && (p->pindex < end))) {
1604 if (p->wire_count != 0) {
1605 vm_page_protect(p, VM_PROT_NONE);
1612 * The busy flags are only cleared at
1613 * interrupt -- minimize the spl transitions
1616 if (vm_page_sleep_busy(p, TRUE, "vmopar"))
1619 if (clean_only && p->valid) {
1620 vm_page_test_dirty(p);
1621 if (p->valid & p->dirty)
1626 vm_page_protect(p, VM_PROT_NONE);
1632 if ((p = vm_page_lookup(object, start)) != 0) {
1633 if (p->wire_count != 0) {
1634 vm_page_protect(p, VM_PROT_NONE);
1643 * The busy flags are only cleared at
1644 * interrupt -- minimize the spl transitions
1646 if (vm_page_sleep_busy(p, TRUE, "vmopar"))
1649 if (clean_only && p->valid) {
1650 vm_page_test_dirty(p);
1651 if (p->valid & p->dirty) {
1659 vm_page_protect(p, VM_PROT_NONE);
1667 vm_object_pip_wakeup(object);
1671 * Routine: vm_object_coalesce
1672 * Function: Coalesces two objects backing up adjoining
1673 * regions of memory into a single object.
1675 * returns TRUE if objects were combined.
1677 * NOTE: Only works at the moment if the second object is NULL -
1678 * if it's not, which object do we lock first?
1681 * prev_object First object to coalesce
1682 * prev_offset Offset into prev_object
1683 * next_object Second object into coalesce
1684 * next_offset Offset into next_object
1686 * prev_size Size of reference to prev_object
1687 * next_size Size of reference to next_object
1690 * The object must *not* be locked.
1693 vm_object_coalesce(vm_object_t prev_object, vm_pindex_t prev_pindex,
1694 vm_size_t prev_size, vm_size_t next_size)
1696 vm_pindex_t next_pindex;
1698 if (prev_object == NULL) {
1702 if (prev_object->type != OBJT_DEFAULT &&
1703 prev_object->type != OBJT_SWAP) {
1708 * Try to collapse the object first
1710 vm_object_collapse(prev_object);
1713 * Can't coalesce if: . more than one reference . paged out . shadows
1714 * another object . has a copy elsewhere (any of which mean that the
1715 * pages not mapped to prev_entry may be in use anyway)
1718 if (prev_object->backing_object != NULL) {
1722 prev_size >>= PAGE_SHIFT;
1723 next_size >>= PAGE_SHIFT;
1724 next_pindex = prev_pindex + prev_size;
1726 if ((prev_object->ref_count > 1) &&
1727 (prev_object->size != next_pindex)) {
1732 * Remove any pages that may still be in the object from a previous
1735 if (next_pindex < prev_object->size) {
1736 vm_object_page_remove(prev_object,
1738 next_pindex + next_size, FALSE);
1739 if (prev_object->type == OBJT_SWAP)
1740 swap_pager_freespace(prev_object,
1741 next_pindex, next_size);
1745 * Extend the object if necessary.
1747 if (next_pindex + next_size > prev_object->size)
1748 prev_object->size = next_pindex + next_size;
1754 vm_object_set_writeable_dirty(vm_object_t object)
1759 vm_object_set_flag(object, OBJ_WRITEABLE|OBJ_MIGHTBEDIRTY);
1760 if (object->type == OBJT_VNODE &&
1761 (vp = (struct vnode *)object->handle) != NULL) {
1762 if ((vp->v_flag & VOBJDIRTY) == 0) {
1763 lwkt_gettoken(&vlock, vp->v_interlock);
1764 vp->v_flag |= VOBJDIRTY;
1765 lwkt_reltoken(&vlock);
1772 #include "opt_ddb.h"
1774 #include <sys/kernel.h>
1776 #include <sys/cons.h>
1778 #include <ddb/ddb.h>
1780 static int _vm_object_in_map (vm_map_t map, vm_object_t object,
1781 vm_map_entry_t entry);
1782 static int vm_object_in_map (vm_object_t object);
1785 _vm_object_in_map(vm_map_t map, vm_object_t object, vm_map_entry_t entry)
1788 vm_map_entry_t tmpe;
1796 tmpe = map->header.next;
1797 entcount = map->nentries;
1798 while (entcount-- && (tmpe != &map->header)) {
1799 if( _vm_object_in_map(map, object, tmpe)) {
1804 } else if (entry->eflags & MAP_ENTRY_IS_SUB_MAP) {
1805 tmpm = entry->object.sub_map;
1806 tmpe = tmpm->header.next;
1807 entcount = tmpm->nentries;
1808 while (entcount-- && tmpe != &tmpm->header) {
1809 if( _vm_object_in_map(tmpm, object, tmpe)) {
1814 } else if ((obj = entry->object.vm_object) != NULL) {
1815 for(; obj; obj=obj->backing_object)
1816 if( obj == object) {
1824 vm_object_in_map(vm_object_t object)
1827 for (p = allproc.lh_first; p != 0; p = p->p_list.le_next) {
1828 if( !p->p_vmspace /* || (p->p_flag & (P_SYSTEM|P_WEXIT)) */)
1830 if( _vm_object_in_map(&p->p_vmspace->vm_map, object, 0))
1833 if( _vm_object_in_map( kernel_map, object, 0))
1835 if( _vm_object_in_map( pager_map, object, 0))
1837 if( _vm_object_in_map( buffer_map, object, 0))
1839 if( _vm_object_in_map( mb_map, object, 0))
1844 DB_SHOW_COMMAND(vmochk, vm_object_check)
1849 * make sure that internal objs are in a map somewhere
1850 * and none have zero ref counts.
1852 for (object = TAILQ_FIRST(&vm_object_list);
1854 object = TAILQ_NEXT(object, object_list)) {
1855 if (object->handle == NULL &&
1856 (object->type == OBJT_DEFAULT || object->type == OBJT_SWAP)) {
1857 if (object->ref_count == 0) {
1858 db_printf("vmochk: internal obj has zero ref count: %ld\n",
1859 (long)object->size);
1861 if (!vm_object_in_map(object)) {
1863 "vmochk: internal obj is not in a map: "
1864 "ref: %d, size: %lu: 0x%lx, backing_object: %p\n",
1865 object->ref_count, (u_long)object->size,
1866 (u_long)object->size,
1867 (void *)object->backing_object);
1874 * vm_object_print: [ debug ]
1876 DB_SHOW_COMMAND(object, vm_object_print_static)
1878 /* XXX convert args. */
1879 vm_object_t object = (vm_object_t)addr;
1880 boolean_t full = have_addr;
1884 /* XXX count is an (unused) arg. Avoid shadowing it. */
1885 #define count was_count
1893 "Object %p: type=%d, size=0x%lx, res=%d, ref=%d, flags=0x%x\n",
1894 object, (int)object->type, (u_long)object->size,
1895 object->resident_page_count, object->ref_count, object->flags);
1897 * XXX no %qd in kernel. Truncate object->backing_object_offset.
1899 db_iprintf(" sref=%d, backing_object(%d)=(%p)+0x%lx\n",
1900 object->shadow_count,
1901 object->backing_object ? object->backing_object->ref_count : 0,
1902 object->backing_object, (long)object->backing_object_offset);
1909 for (p = TAILQ_FIRST(&object->memq); p != NULL; p = TAILQ_NEXT(p, listq)) {
1911 db_iprintf("memory:=");
1912 else if (count == 6) {
1920 db_printf("(off=0x%lx,page=0x%lx)",
1921 (u_long) p->pindex, (u_long) VM_PAGE_TO_PHYS(p));
1931 /* XXX need this non-static entry for calling from vm_map_print. */
1933 vm_object_print(/* db_expr_t */ long addr,
1934 boolean_t have_addr,
1935 /* db_expr_t */ long count,
1938 vm_object_print_static(addr, have_addr, count, modif);
1941 DB_SHOW_COMMAND(vmopag, vm_object_print_pages)
1946 for (object = TAILQ_FIRST(&vm_object_list);
1948 object = TAILQ_NEXT(object, object_list)) {
1949 vm_pindex_t idx, fidx;
1951 vm_paddr_t pa = -1, padiff;
1955 db_printf("new object: %p\n", (void *)object);
1965 osize = object->size;
1968 for (idx = 0; idx < osize; idx++) {
1969 m = vm_page_lookup(object, idx);
1972 db_printf(" index(%ld)run(%d)pa(0x%lx)\n",
1973 (long)fidx, rcount, (long)pa);
1988 (VM_PAGE_TO_PHYS(m) == pa + rcount * PAGE_SIZE)) {
1993 padiff = pa + rcount * PAGE_SIZE - VM_PAGE_TO_PHYS(m);
1994 padiff >>= PAGE_SHIFT;
1995 padiff &= PQ_L2_MASK;
1997 pa = VM_PAGE_TO_PHYS(m) - rcount * PAGE_SIZE;
2001 db_printf(" index(%ld)run(%d)pa(0x%lx)",
2002 (long)fidx, rcount, (long)pa);
2003 db_printf("pd(%ld)\n", (long)padiff);
2013 pa = VM_PAGE_TO_PHYS(m);
2017 db_printf(" index(%ld)run(%d)pa(0x%lx)\n",
2018 (long)fidx, rcount, (long)pa);