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. All advertising materials mentioning features or use of this software
19 * must display the following acknowledgement:
20 * This product includes software developed by the University of
21 * California, Berkeley and its contributors.
22 * 4. Neither the name of the University nor the names of its contributors
23 * may be used to endorse or promote products derived from this software
24 * without specific prior written permission.
26 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
27 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
28 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
29 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
30 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
31 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
32 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
33 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
34 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
35 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
38 * from: @(#)vm_object.c 8.5 (Berkeley) 3/22/94
41 * Copyright (c) 1987, 1990 Carnegie-Mellon University.
42 * All rights reserved.
44 * Authors: Avadis Tevanian, Jr., Michael Wayne Young
46 * Permission to use, copy, modify and distribute this software and
47 * its documentation is hereby granted, provided that both the copyright
48 * notice and this permission notice appear in all copies of the
49 * software, derivative works or modified versions, and any portions
50 * thereof, and that both notices appear in supporting documentation.
52 * CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS"
53 * CONDITION. CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND
54 * FOR ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
56 * Carnegie Mellon requests users of this software to return to
58 * Software Distribution Coordinator or Software.Distribution@CS.CMU.EDU
59 * School of Computer Science
60 * Carnegie Mellon University
61 * Pittsburgh PA 15213-3890
63 * any improvements or extensions that they make and grant Carnegie the
64 * rights to redistribute these changes.
66 * $FreeBSD: src/sys/vm/vm_object.c,v 1.171.2.8 2003/05/26 19:17:56 alc Exp $
70 * Virtual memory object module.
73 #include <sys/param.h>
74 #include <sys/systm.h>
75 #include <sys/proc.h> /* for curproc, pageproc */
76 #include <sys/thread.h>
77 #include <sys/vnode.h>
78 #include <sys/vmmeter.h>
80 #include <sys/mount.h>
81 #include <sys/kernel.h>
82 #include <sys/sysctl.h>
83 #include <sys/refcount.h>
86 #include <vm/vm_param.h>
88 #include <vm/vm_map.h>
89 #include <vm/vm_object.h>
90 #include <vm/vm_page.h>
91 #include <vm/vm_pageout.h>
92 #include <vm/vm_pager.h>
93 #include <vm/swap_pager.h>
94 #include <vm/vm_kern.h>
95 #include <vm/vm_extern.h>
96 #include <vm/vm_zone.h>
98 #define EASY_SCAN_FACTOR 8
100 static void vm_object_qcollapse(vm_object_t object);
101 static int vm_object_page_collect_flush(vm_object_t object, vm_page_t p,
103 static void vm_object_lock_init(vm_object_t);
104 static void vm_object_hold_wait(vm_object_t);
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; /* locked by vmobj_token */
134 struct vm_object kernel_object;
136 static long vm_object_count; /* locked by vmobj_token */
137 extern int vm_pageout_page_count;
139 static long object_collapses;
140 static long object_bypasses;
141 static int next_index;
142 static vm_zone_t obj_zone;
143 static struct vm_zone obj_zone_store;
144 #define VM_OBJECTS_INIT 256
145 static struct vm_object vm_objects_init[VM_OBJECTS_INIT];
148 * Misc low level routines
151 vm_object_lock_init(vm_object_t obj)
153 #if defined(DEBUG_LOCKS)
156 obj->debug_hold_bitmap = 0;
157 obj->debug_hold_ovfl = 0;
158 for (i = 0; i < VMOBJ_DEBUG_ARRAY_SIZE; i++) {
159 obj->debug_hold_thrs[i] = NULL;
160 obj->debug_hold_file[i] = NULL;
161 obj->debug_hold_line[i] = 0;
167 vm_object_lock_swap(void)
173 vm_object_lock(vm_object_t obj)
175 lwkt_getpooltoken(obj);
179 vm_object_unlock(vm_object_t obj)
181 lwkt_relpooltoken(obj);
185 vm_object_assert_held(vm_object_t obj)
187 ASSERT_LWKT_TOKEN_HELD(lwkt_token_pool_lookup(obj));
192 vm_object_hold(vm_object_t obj)
194 debugvm_object_hold(vm_object_t obj, char *file, int line)
201 * Object must be held (object allocation is stable due to callers
202 * context, typically already holding the token on a parent object)
203 * prior to potentially blocking on the lock, otherwise the object
204 * can get ripped away from us.
206 refcount_acquire(&obj->hold_count);
209 #if defined(DEBUG_LOCKS)
212 i = ffs(~obj->debug_hold_bitmap) - 1;
214 kprintf("vm_object hold count > VMOBJ_DEBUG_ARRAY_SIZE");
215 obj->debug_hold_ovfl = 1;
218 obj->debug_hold_bitmap |= (1 << i);
219 obj->debug_hold_thrs[i] = curthread;
220 obj->debug_hold_file[i] = file;
221 obj->debug_hold_line[i] = line;
226 vm_object_drop(vm_object_t obj)
231 #if defined(DEBUG_LOCKS)
235 for (i = 0; i < VMOBJ_DEBUG_ARRAY_SIZE; i++) {
236 if ((obj->debug_hold_bitmap & (1 << i)) &&
237 (obj->debug_hold_thrs[i] == curthread)) {
238 obj->debug_hold_bitmap &= ~(1 << i);
239 obj->debug_hold_thrs[i] = NULL;
240 obj->debug_hold_file[i] = NULL;
241 obj->debug_hold_line[i] = 0;
247 if (found == 0 && obj->debug_hold_ovfl == 0)
248 panic("vm_object: attempt to drop hold on non-self-held obj");
252 * The lock is a pool token, keep holding it across potential
253 * wakeups to interlock the tsleep/wakeup.
255 if (refcount_release(&obj->hold_count))
257 vm_object_unlock(obj);
261 * This can only be called while the caller holds the object
262 * with the OBJ_DEAD interlock. Since there are no refs this
263 * is the only thing preventing an object destruction race.
266 vm_object_hold_wait(vm_object_t obj)
270 #if defined(DEBUG_LOCKS)
273 for (i = 0; i < VMOBJ_DEBUG_ARRAY_SIZE; i++) {
274 if ((obj->debug_hold_bitmap & (1 << i)) &&
275 (obj->debug_hold_thrs[i] == curthread)) {
276 kprintf("vm_object %p: self-hold in at %s:%d\n", obj,
277 obj->debug_hold_file[i], obj->debug_hold_line[i]);
278 panic("vm_object: self-hold in terminate or collapse");
283 while (obj->hold_count)
284 tsleep(obj, 0, "vmobjhld", 0);
286 vm_object_unlock(obj);
291 * Initialize a freshly allocated object
293 * Used only by vm_object_allocate() and zinitna().
298 _vm_object_allocate(objtype_t type, vm_pindex_t size, vm_object_t object)
302 RB_INIT(&object->rb_memq);
303 LIST_INIT(&object->shadow_head);
307 object->ref_count = 1;
308 object->hold_count = 0;
310 if ((object->type == OBJT_DEFAULT) || (object->type == OBJT_SWAP))
311 vm_object_set_flag(object, OBJ_ONEMAPPING);
312 object->paging_in_progress = 0;
313 object->resident_page_count = 0;
314 object->agg_pv_list_count = 0;
315 object->shadow_count = 0;
316 object->pg_color = next_index;
317 if ( size > (PQ_L2_SIZE / 3 + PQ_PRIME1))
318 incr = PQ_L2_SIZE / 3 + PQ_PRIME1;
321 next_index = (next_index + incr) & PQ_L2_MASK;
322 object->handle = NULL;
323 object->backing_object = NULL;
324 object->backing_object_offset = (vm_ooffset_t) 0;
326 object->generation++;
327 object->swblock_count = 0;
328 RB_INIT(&object->swblock_root);
329 vm_object_lock_init(object);
331 lwkt_gettoken(&vmobj_token);
332 TAILQ_INSERT_TAIL(&vm_object_list, object, object_list);
334 lwkt_reltoken(&vmobj_token);
338 * Initialize the VM objects module.
340 * Called from the low level boot code only.
345 TAILQ_INIT(&vm_object_list);
347 _vm_object_allocate(OBJT_DEFAULT, OFF_TO_IDX(KvaEnd),
350 obj_zone = &obj_zone_store;
351 zbootinit(obj_zone, "VM OBJECT", sizeof (struct vm_object),
352 vm_objects_init, VM_OBJECTS_INIT);
356 vm_object_init2(void)
358 zinitna(obj_zone, NULL, NULL, 0, 0, ZONE_PANICFAIL, 1);
362 * Allocate and return a new object of the specified type and size.
367 vm_object_allocate(objtype_t type, vm_pindex_t size)
371 result = (vm_object_t) zalloc(obj_zone);
373 _vm_object_allocate(type, size, result);
379 * Add an additional reference to a vm_object.
381 * Object passed by caller must be stable or caller must already
382 * hold vmobj_token to avoid races.
385 vm_object_reference(vm_object_t object)
387 lwkt_gettoken(&vmobj_token);
388 vm_object_hold(object);
389 vm_object_reference_locked(object);
390 vm_object_drop(object);
391 lwkt_reltoken(&vmobj_token);
395 vm_object_reference_locked(vm_object_t object)
398 ASSERT_LWKT_TOKEN_HELD(&vmobj_token);
400 /*ASSERT_LWKT_TOKEN_HELD(vm_object_token(object));*/
402 if (object->type == OBJT_VNODE) {
403 vref(object->handle);
404 /* XXX what if the vnode is being destroyed? */
410 * Dereference an object and its underlying vnode.
412 * The caller must hold vmobj_token.
413 * The object must be locked but not held. This function will eat the lock.
416 vm_object_vndeallocate(vm_object_t object)
418 struct vnode *vp = (struct vnode *) object->handle;
420 KASSERT(object->type == OBJT_VNODE,
421 ("vm_object_vndeallocate: not a vnode object"));
422 KASSERT(vp != NULL, ("vm_object_vndeallocate: missing vp"));
423 ASSERT_LWKT_TOKEN_HELD(&vmobj_token);
425 if (object->ref_count == 0) {
426 vprint("vm_object_vndeallocate", vp);
427 panic("vm_object_vndeallocate: bad object reference count");
432 if (object->ref_count == 0)
433 vclrflags(vp, VTEXT);
434 vm_object_unlock(object);
439 * Release a reference to the specified object, gained either through a
440 * vm_object_allocate or a vm_object_reference call. When all references
441 * are gone, storage associated with this object may be relinquished.
443 * The caller does not have to hold the object locked but must have control
444 * over the reference in question in order to guarantee that the object
445 * does not get ripped out from under us.
448 vm_object_deallocate(vm_object_t object)
450 lwkt_gettoken(&vmobj_token);
451 vm_object_deallocate_locked(object);
452 lwkt_reltoken(&vmobj_token);
456 vm_object_deallocate_locked(vm_object_t object)
460 ASSERT_LWKT_TOKEN_HELD(&vmobj_token);
463 vm_object_lock(object);
465 while (object != NULL) {
466 if (object->type == OBJT_VNODE) {
467 vm_object_vndeallocate(object);
468 /* vndeallocate ate the lock */
472 if (object->ref_count == 0) {
473 panic("vm_object_deallocate: object deallocated "
474 "too many times: %d", object->type);
476 if (object->ref_count > 2) {
478 vm_object_unlock(object);
483 * We currently need the vm_token from this point on, and
484 * we must recheck ref_count after acquiring it.
486 lwkt_gettoken(&vm_token);
488 if (object->ref_count > 2) {
490 lwkt_reltoken(&vm_token);
491 vm_object_unlock(object);
496 * Here on ref_count of one or two, which are special cases for
499 * Nominal ref_count > 1 case if the second ref is not from
502 if (object->ref_count == 2 && object->shadow_count == 0) {
503 vm_object_set_flag(object, OBJ_ONEMAPPING);
505 lwkt_reltoken(&vm_token);
506 vm_object_unlock(object);
511 * If the second ref is from a shadow we chain along it
512 * if object's handle is exhausted.
514 * We have to decrement object->ref_count before potentially
515 * collapsing the first shadow object or the collapse code
516 * will not be able to handle the degenerate case.
518 if (object->ref_count == 2 && object->shadow_count == 1) {
520 if (object->handle == NULL &&
521 (object->type == OBJT_DEFAULT ||
522 object->type == OBJT_SWAP)) {
523 temp = LIST_FIRST(&object->shadow_head);
524 KASSERT(temp != NULL,
525 ("vm_object_deallocate: ref_count: "
526 "%d, shadow_count: %d",
528 object->shadow_count));
529 lwkt_reltoken(&vm_token);
530 vm_object_lock(temp);
532 if ((temp->handle == NULL) &&
533 (temp->type == OBJT_DEFAULT ||
534 temp->type == OBJT_SWAP)) {
536 * Special case, must handle ref_count
537 * manually to avoid recursion.
540 vm_object_lock_swap();
543 temp->paging_in_progress ||
544 object->paging_in_progress
546 vm_object_pip_wait(temp,
548 vm_object_pip_wait(object,
552 if (temp->ref_count == 1) {
554 vm_object_unlock(object);
559 lwkt_gettoken(&vm_token);
560 vm_object_collapse(temp);
561 lwkt_reltoken(&vm_token);
562 vm_object_unlock(object);
566 vm_object_unlock(temp);
568 lwkt_reltoken(&vm_token);
570 vm_object_unlock(object);
575 * Normal dereferencing path
578 if (object->ref_count != 0) {
579 lwkt_reltoken(&vm_token);
580 vm_object_unlock(object);
587 * We may have to loop to resolve races if we block getting
588 * temp's lock. If temp is non NULL we have to swap the
589 * lock order so the original object lock as at the top
592 lwkt_reltoken(&vm_token);
594 while ((temp = object->backing_object) != NULL) {
595 vm_object_lock(temp);
596 if (temp == object->backing_object)
598 vm_object_unlock(temp);
601 LIST_REMOVE(object, shadow_list);
602 temp->shadow_count--;
604 object->backing_object = NULL;
605 vm_object_lock_swap();
609 * Don't double-terminate, we could be in a termination
610 * recursion due to the terminate having to sync data
613 if ((object->flags & OBJ_DEAD) == 0) {
614 vm_object_terminate(object);
615 /* termination ate the object lock */
617 vm_object_unlock(object);
624 * Destroy the specified object, freeing up related resources.
626 * The object must have zero references.
628 * The caller must be holding vmobj_token and properly interlock with
629 * OBJ_DEAD (at the moment).
631 * The caller must have locked the object only, and not be holding it.
632 * This function will eat the caller's lock on the object.
634 static int vm_object_terminate_callback(vm_page_t p, void *data);
637 vm_object_terminate(vm_object_t object)
640 * Make sure no one uses us. Once we set OBJ_DEAD we should be
641 * able to safely block.
643 KKASSERT((object->flags & OBJ_DEAD) == 0);
644 ASSERT_LWKT_TOKEN_HELD(&vmobj_token);
645 vm_object_set_flag(object, OBJ_DEAD);
648 * Wait for the pageout daemon to be done with the object
650 vm_object_pip_wait(object, "objtrm1");
652 KASSERT(!object->paging_in_progress,
653 ("vm_object_terminate: pageout in progress"));
656 * Clean and free the pages, as appropriate. All references to the
657 * object are gone, so we don't need to lock it.
659 if (object->type == OBJT_VNODE) {
663 * Clean pages and flush buffers.
665 vm_object_page_clean(object, 0, 0, OBJPC_SYNC);
667 vp = (struct vnode *) object->handle;
668 vinvalbuf(vp, V_SAVE, 0, 0);
672 * Wait for any I/O to complete, after which there had better not
673 * be any references left on the object.
675 vm_object_pip_wait(object, "objtrm2");
677 if (object->ref_count != 0) {
678 panic("vm_object_terminate: object with references, "
679 "ref_count=%d", object->ref_count);
683 * Now free any remaining pages. For internal objects, this also
684 * removes them from paging queues. Don't free wired pages, just
685 * remove them from the object.
687 lwkt_gettoken(&vm_token);
688 vm_page_rb_tree_RB_SCAN(&object->rb_memq, NULL,
689 vm_object_terminate_callback, NULL);
690 lwkt_reltoken(&vm_token);
693 * Let the pager know object is dead.
695 vm_pager_deallocate(object);
698 * Wait for the object hold count to hit zero, clean out pages as
701 lwkt_gettoken(&vm_token);
703 vm_object_hold_wait(object);
704 if (RB_ROOT(&object->rb_memq) == NULL)
706 kprintf("vm_object_terminate: Warning, object %p "
707 "still has %d pages\n",
708 object, object->resident_page_count);
709 vm_page_rb_tree_RB_SCAN(&object->rb_memq, NULL,
710 vm_object_terminate_callback, NULL);
712 lwkt_reltoken(&vm_token);
715 * There had better not be any pages left
717 KKASSERT(object->resident_page_count == 0);
720 * Remove the object from the global object list.
722 * (we are holding vmobj_token)
724 TAILQ_REMOVE(&vm_object_list, object, object_list);
726 vm_object_dead_wakeup(object);
727 vm_object_unlock(object);
729 if (object->ref_count != 0) {
730 panic("vm_object_terminate2: object with references, "
731 "ref_count=%d", object->ref_count);
735 * Free the space for the object.
737 zfree(obj_zone, object);
741 * The caller must hold vm_token.
744 vm_object_terminate_callback(vm_page_t p, void *data __unused)
746 if (p->busy || (p->flags & PG_BUSY))
747 panic("vm_object_terminate: freeing busy page %p", p);
748 if (p->wire_count == 0) {
751 mycpu->gd_cnt.v_pfree++;
753 if (p->queue != PQ_NONE)
754 kprintf("vm_object_terminate: Warning: Encountered wired page %p on queue %d\n", p, p->queue);
763 * The object is dead but still has an object<->pager association. Sleep
764 * and return. The caller typically retests the association in a loop.
766 * Must be called with the vmobj_token held.
769 vm_object_dead_sleep(vm_object_t object, const char *wmesg)
771 ASSERT_LWKT_TOKEN_HELD(&vmobj_token);
772 if (object->handle) {
773 vm_object_set_flag(object, OBJ_DEADWNT);
774 tsleep(object, 0, wmesg, 0);
775 /* object may be invalid after this point */
780 * Wakeup anyone waiting for the object<->pager disassociation on
783 * Must be called with the vmobj_token held.
786 vm_object_dead_wakeup(vm_object_t object)
788 ASSERT_LWKT_TOKEN_HELD(&vmobj_token);
789 if (object->flags & OBJ_DEADWNT) {
790 vm_object_clear_flag(object, OBJ_DEADWNT);
796 * Clean all dirty pages in the specified range of object. Leaves page
797 * on whatever queue it is currently on. If NOSYNC is set then do not
798 * write out pages with PG_NOSYNC set (originally comes from MAP_NOSYNC),
799 * leaving the object dirty.
801 * When stuffing pages asynchronously, allow clustering. XXX we need a
802 * synchronous clustering mode implementation.
804 * Odd semantics: if start == end, we clean everything.
806 * The object must be locked? XXX
808 static int vm_object_page_clean_pass1(struct vm_page *p, void *data);
809 static int vm_object_page_clean_pass2(struct vm_page *p, void *data);
812 vm_object_page_clean(vm_object_t object, vm_pindex_t start, vm_pindex_t end,
815 struct rb_vm_page_scan_info info;
821 vm_object_hold(object);
822 if (object->type != OBJT_VNODE ||
823 (object->flags & OBJ_MIGHTBEDIRTY) == 0) {
824 vm_object_drop(object);
828 pagerflags = (flags & (OBJPC_SYNC | OBJPC_INVAL)) ?
829 VM_PAGER_PUT_SYNC : VM_PAGER_CLUSTER_OK;
830 pagerflags |= (flags & OBJPC_INVAL) ? VM_PAGER_PUT_INVAL : 0;
835 * Interlock other major object operations. This allows us to
836 * temporarily clear OBJ_WRITEABLE and OBJ_MIGHTBEDIRTY.
839 vm_object_set_flag(object, OBJ_CLEANING);
842 * Handle 'entire object' case
844 info.start_pindex = start;
846 info.end_pindex = object->size - 1;
848 info.end_pindex = end - 1;
850 wholescan = (start == 0 && info.end_pindex == object->size - 1);
852 info.pagerflags = pagerflags;
853 info.object = object;
856 * If cleaning the entire object do a pass to mark the pages read-only.
857 * If everything worked out ok, clear OBJ_WRITEABLE and
862 lwkt_gettoken(&vm_token);
863 vm_page_rb_tree_RB_SCAN(&object->rb_memq, rb_vm_page_scancmp,
864 vm_object_page_clean_pass1, &info);
865 lwkt_reltoken(&vm_token);
866 if (info.error == 0) {
867 vm_object_clear_flag(object,
868 OBJ_WRITEABLE|OBJ_MIGHTBEDIRTY);
869 if (object->type == OBJT_VNODE &&
870 (vp = (struct vnode *)object->handle) != NULL) {
871 if (vp->v_flag & VOBJDIRTY)
872 vclrflags(vp, VOBJDIRTY);
878 * Do a pass to clean all the dirty pages we find.
882 curgeneration = object->generation;
883 lwkt_gettoken(&vm_token);
884 vm_page_rb_tree_RB_SCAN(&object->rb_memq, rb_vm_page_scancmp,
885 vm_object_page_clean_pass2, &info);
886 lwkt_reltoken(&vm_token);
887 } while (info.error || curgeneration != object->generation);
889 vm_object_clear_flag(object, OBJ_CLEANING);
891 vm_object_drop(object);
895 * The caller must hold vm_token.
899 vm_object_page_clean_pass1(struct vm_page *p, void *data)
901 struct rb_vm_page_scan_info *info = data;
903 vm_page_flag_set(p, PG_CLEANCHK);
904 if ((info->limit & OBJPC_NOSYNC) && (p->flags & PG_NOSYNC))
907 vm_page_protect(p, VM_PROT_READ); /* must not block */
912 * The caller must hold vm_token.
916 vm_object_page_clean_pass2(struct vm_page *p, void *data)
918 struct rb_vm_page_scan_info *info = data;
922 * Do not mess with pages that were inserted after we started
925 if ((p->flags & PG_CLEANCHK) == 0)
929 * Before wasting time traversing the pmaps, check for trivial
930 * cases where the page cannot be dirty.
932 if (p->valid == 0 || (p->queue - p->pc) == PQ_CACHE) {
933 KKASSERT((p->dirty & p->valid) == 0);
938 * Check whether the page is dirty or not. The page has been set
939 * to be read-only so the check will not race a user dirtying the
942 vm_page_test_dirty(p);
943 if ((p->dirty & p->valid) == 0) {
944 vm_page_flag_clear(p, PG_CLEANCHK);
949 * If we have been asked to skip nosync pages and this is a
950 * nosync page, skip it. Note that the object flags were
951 * not cleared in this case (because pass1 will have returned an
952 * error), so we do not have to set them.
954 if ((info->limit & OBJPC_NOSYNC) && (p->flags & PG_NOSYNC)) {
955 vm_page_flag_clear(p, PG_CLEANCHK);
960 * Flush as many pages as we can. PG_CLEANCHK will be cleared on
961 * the pages that get successfully flushed. Set info->error if
962 * we raced an object modification.
964 n = vm_object_page_collect_flush(info->object, p, info->pagerflags);
971 * Collect the specified page and nearby pages and flush them out.
972 * The number of pages flushed is returned.
974 * The caller must hold vm_token.
977 vm_object_page_collect_flush(vm_object_t object, vm_page_t p, int pagerflags)
986 vm_page_t maf[vm_pageout_page_count];
987 vm_page_t mab[vm_pageout_page_count];
988 vm_page_t ma[vm_pageout_page_count];
990 curgeneration = object->generation;
993 while (vm_page_sleep_busy(p, TRUE, "vpcwai")) {
994 if (object->generation != curgeneration) {
998 KKASSERT(p->object == object && p->pindex == pi);
1001 for(i = 1; i < vm_pageout_page_count; i++) {
1004 if ((tp = vm_page_lookup(object, pi + i)) != NULL) {
1005 if ((tp->flags & PG_BUSY) ||
1006 ((pagerflags & VM_PAGER_IGNORE_CLEANCHK) == 0 &&
1007 (tp->flags & PG_CLEANCHK) == 0) ||
1010 if((tp->queue - tp->pc) == PQ_CACHE) {
1011 vm_page_flag_clear(tp, PG_CLEANCHK);
1014 vm_page_test_dirty(tp);
1015 if ((tp->dirty & tp->valid) == 0) {
1016 vm_page_flag_clear(tp, PG_CLEANCHK);
1027 chkb = vm_pageout_page_count - maxf;
1029 for(i = 1; i < chkb;i++) {
1032 if ((tp = vm_page_lookup(object, pi - i)) != NULL) {
1033 if ((tp->flags & PG_BUSY) ||
1034 ((pagerflags & VM_PAGER_IGNORE_CLEANCHK) == 0 &&
1035 (tp->flags & PG_CLEANCHK) == 0) ||
1038 if((tp->queue - tp->pc) == PQ_CACHE) {
1039 vm_page_flag_clear(tp, PG_CLEANCHK);
1042 vm_page_test_dirty(tp);
1043 if ((tp->dirty & tp->valid) == 0) {
1044 vm_page_flag_clear(tp, PG_CLEANCHK);
1055 for(i = 0; i < maxb; i++) {
1056 int index = (maxb - i) - 1;
1058 vm_page_flag_clear(ma[index], PG_CLEANCHK);
1060 vm_page_flag_clear(p, PG_CLEANCHK);
1062 for(i = 0; i < maxf; i++) {
1063 int index = (maxb + i) + 1;
1065 vm_page_flag_clear(ma[index], PG_CLEANCHK);
1067 runlen = maxb + maxf + 1;
1069 vm_pageout_flush(ma, runlen, pagerflags);
1070 for (i = 0; i < runlen; i++) {
1071 if (ma[i]->valid & ma[i]->dirty) {
1072 vm_page_protect(ma[i], VM_PROT_READ);
1073 vm_page_flag_set(ma[i], PG_CLEANCHK);
1076 * maxf will end up being the actual number of pages
1077 * we wrote out contiguously, non-inclusive of the
1078 * first page. We do not count look-behind pages.
1080 if (i >= maxb + 1 && (maxf > i - maxb - 1))
1081 maxf = i - maxb - 1;
1088 * Same as vm_object_pmap_copy, except range checking really
1089 * works, and is meant for small sections of an object.
1091 * This code protects resident pages by making them read-only
1092 * and is typically called on a fork or split when a page
1093 * is converted to copy-on-write.
1095 * NOTE: If the page is already at VM_PROT_NONE, calling
1096 * vm_page_protect will have no effect.
1099 vm_object_pmap_copy_1(vm_object_t object, vm_pindex_t start, vm_pindex_t end)
1104 if (object == NULL || (object->flags & OBJ_WRITEABLE) == 0)
1108 * spl protection needed to prevent races between the lookup,
1109 * an interrupt unbusy/free, and our protect call.
1112 lwkt_gettoken(&vm_token);
1113 for (idx = start; idx < end; idx++) {
1114 p = vm_page_lookup(object, idx);
1117 vm_page_protect(p, VM_PROT_READ);
1119 lwkt_reltoken(&vm_token);
1124 * Removes all physical pages in the specified object range from all
1127 * The object must *not* be locked.
1130 static int vm_object_pmap_remove_callback(vm_page_t p, void *data);
1133 vm_object_pmap_remove(vm_object_t object, vm_pindex_t start, vm_pindex_t end)
1135 struct rb_vm_page_scan_info info;
1139 info.start_pindex = start;
1140 info.end_pindex = end - 1;
1143 lwkt_gettoken(&vm_token);
1144 vm_page_rb_tree_RB_SCAN(&object->rb_memq, rb_vm_page_scancmp,
1145 vm_object_pmap_remove_callback, &info);
1146 if (start == 0 && end == object->size)
1147 vm_object_clear_flag(object, OBJ_WRITEABLE);
1148 lwkt_reltoken(&vm_token);
1153 * The caller must hold vm_token.
1156 vm_object_pmap_remove_callback(vm_page_t p, void *data __unused)
1158 vm_page_protect(p, VM_PROT_NONE);
1163 * Implements the madvise function at the object/page level.
1165 * MADV_WILLNEED (any object)
1167 * Activate the specified pages if they are resident.
1169 * MADV_DONTNEED (any object)
1171 * Deactivate the specified pages if they are resident.
1173 * MADV_FREE (OBJT_DEFAULT/OBJT_SWAP objects, OBJ_ONEMAPPING only)
1175 * Deactivate and clean the specified pages if they are
1176 * resident. This permits the process to reuse the pages
1177 * without faulting or the kernel to reclaim the pages
1183 vm_object_madvise(vm_object_t object, vm_pindex_t pindex, int count, int advise)
1185 vm_pindex_t end, tpindex;
1186 vm_object_t tobject;
1192 end = pindex + count;
1194 lwkt_gettoken(&vm_token);
1197 * Locate and adjust resident pages
1199 for (; pindex < end; pindex += 1) {
1205 * MADV_FREE only operates on OBJT_DEFAULT or OBJT_SWAP pages
1206 * and those pages must be OBJ_ONEMAPPING.
1208 if (advise == MADV_FREE) {
1209 if ((tobject->type != OBJT_DEFAULT &&
1210 tobject->type != OBJT_SWAP) ||
1211 (tobject->flags & OBJ_ONEMAPPING) == 0) {
1217 * spl protection is required to avoid a race between the
1218 * lookup, an interrupt unbusy/free, and our busy check.
1222 m = vm_page_lookup(tobject, tpindex);
1226 * There may be swap even if there is no backing page
1228 if (advise == MADV_FREE && tobject->type == OBJT_SWAP)
1229 swap_pager_freespace(tobject, tpindex, 1);
1235 if (tobject->backing_object == NULL)
1237 tpindex += OFF_TO_IDX(tobject->backing_object_offset);
1238 tobject = tobject->backing_object;
1243 * If the page is busy or not in a normal active state,
1244 * we skip it. If the page is not managed there are no
1245 * page queues to mess with. Things can break if we mess
1246 * with pages in any of the below states.
1251 (m->flags & PG_UNMANAGED) ||
1252 m->valid != VM_PAGE_BITS_ALL
1258 if (vm_page_sleep_busy(m, TRUE, "madvpo")) {
1266 * Theoretically once a page is known not to be busy, an
1267 * interrupt cannot come along and rip it out from under us.
1270 if (advise == MADV_WILLNEED) {
1271 vm_page_activate(m);
1272 } else if (advise == MADV_DONTNEED) {
1273 vm_page_dontneed(m);
1274 } else if (advise == MADV_FREE) {
1276 * Mark the page clean. This will allow the page
1277 * to be freed up by the system. However, such pages
1278 * are often reused quickly by malloc()/free()
1279 * so we do not do anything that would cause
1280 * a page fault if we can help it.
1282 * Specifically, we do not try to actually free
1283 * the page now nor do we try to put it in the
1284 * cache (which would cause a page fault on reuse).
1286 * But we do make the page is freeable as we
1287 * can without actually taking the step of unmapping
1290 pmap_clear_modify(m);
1293 vm_page_dontneed(m);
1294 if (tobject->type == OBJT_SWAP)
1295 swap_pager_freespace(tobject, tpindex, 1);
1299 lwkt_reltoken(&vm_token);
1303 * Create a new object which is backed by the specified existing object
1304 * range. The source object reference is deallocated.
1306 * The new object and offset into that object are returned in the source
1309 * No other requirements.
1312 vm_object_shadow(vm_object_t *object, vm_ooffset_t *offset, vm_size_t length)
1320 * Don't create the new object if the old object isn't shared.
1322 lwkt_gettoken(&vm_token);
1324 if (source != NULL &&
1325 source->ref_count == 1 &&
1326 source->handle == NULL &&
1327 (source->type == OBJT_DEFAULT ||
1328 source->type == OBJT_SWAP)) {
1329 lwkt_reltoken(&vm_token);
1334 * Allocate a new object with the given length
1337 if ((result = vm_object_allocate(OBJT_DEFAULT, length)) == NULL)
1338 panic("vm_object_shadow: no object for shadowing");
1341 * The new object shadows the source object, adding a reference to it.
1342 * Our caller changes his reference to point to the new object,
1343 * removing a reference to the source object. Net result: no change
1344 * of reference count.
1346 * Try to optimize the result object's page color when shadowing
1347 * in order to maintain page coloring consistency in the combined
1350 result->backing_object = source;
1352 LIST_INSERT_HEAD(&source->shadow_head, result, shadow_list);
1353 source->shadow_count++;
1354 source->generation++;
1355 result->pg_color = (source->pg_color + OFF_TO_IDX(*offset)) & PQ_L2_MASK;
1359 * Store the offset into the source object, and fix up the offset into
1362 result->backing_object_offset = *offset;
1363 lwkt_reltoken(&vm_token);
1366 * Return the new things
1372 #define OBSC_TEST_ALL_SHADOWED 0x0001
1373 #define OBSC_COLLAPSE_NOWAIT 0x0002
1374 #define OBSC_COLLAPSE_WAIT 0x0004
1376 static int vm_object_backing_scan_callback(vm_page_t p, void *data);
1379 * The caller must hold vm_token.
1382 vm_object_backing_scan(vm_object_t object, int op)
1384 struct rb_vm_page_scan_info info;
1385 vm_object_t backing_object;
1389 backing_object = object->backing_object;
1390 info.backing_offset_index = OFF_TO_IDX(object->backing_object_offset);
1393 * Initial conditions
1396 if (op & OBSC_TEST_ALL_SHADOWED) {
1398 * We do not want to have to test for the existence of
1399 * swap pages in the backing object. XXX but with the
1400 * new swapper this would be pretty easy to do.
1402 * XXX what about anonymous MAP_SHARED memory that hasn't
1403 * been ZFOD faulted yet? If we do not test for this, the
1404 * shadow test may succeed! XXX
1406 if (backing_object->type != OBJT_DEFAULT) {
1411 if (op & OBSC_COLLAPSE_WAIT) {
1412 KKASSERT((backing_object->flags & OBJ_DEAD) == 0);
1413 vm_object_set_flag(backing_object, OBJ_DEAD);
1417 * Our scan. We have to retry if a negative error code is returned,
1418 * otherwise 0 or 1 will be returned in info.error. 0 Indicates that
1419 * the scan had to be stopped because the parent does not completely
1422 info.object = object;
1423 info.backing_object = backing_object;
1427 vm_page_rb_tree_RB_SCAN(&backing_object->rb_memq, NULL,
1428 vm_object_backing_scan_callback,
1430 } while (info.error < 0);
1436 * The caller must hold vm_token.
1439 vm_object_backing_scan_callback(vm_page_t p, void *data)
1441 struct rb_vm_page_scan_info *info = data;
1442 vm_object_t backing_object;
1444 vm_pindex_t new_pindex;
1445 vm_pindex_t backing_offset_index;
1448 new_pindex = p->pindex - info->backing_offset_index;
1450 object = info->object;
1451 backing_object = info->backing_object;
1452 backing_offset_index = info->backing_offset_index;
1454 if (op & OBSC_TEST_ALL_SHADOWED) {
1458 * Ignore pages outside the parent object's range
1459 * and outside the parent object's mapping of the
1462 * note that we do not busy the backing object's
1466 p->pindex < backing_offset_index ||
1467 new_pindex >= object->size
1473 * See if the parent has the page or if the parent's
1474 * object pager has the page. If the parent has the
1475 * page but the page is not valid, the parent's
1476 * object pager must have the page.
1478 * If this fails, the parent does not completely shadow
1479 * the object and we might as well give up now.
1482 pp = vm_page_lookup(object, new_pindex);
1483 if ((pp == NULL || pp->valid == 0) &&
1484 !vm_pager_has_page(object, new_pindex)
1486 info->error = 0; /* problemo */
1487 return(-1); /* stop the scan */
1492 * Check for busy page
1495 if (op & (OBSC_COLLAPSE_WAIT | OBSC_COLLAPSE_NOWAIT)) {
1498 if (op & OBSC_COLLAPSE_NOWAIT) {
1500 (p->flags & PG_BUSY) ||
1508 } else if (op & OBSC_COLLAPSE_WAIT) {
1509 if (vm_page_sleep_busy(p, TRUE, "vmocol")) {
1511 * If we slept, anything could have
1512 * happened. Ask that the scan be restarted.
1514 * Since the object is marked dead, the
1515 * backing offset should not have changed.
1528 p->object == backing_object,
1529 ("vm_object_qcollapse(): object mismatch")
1533 * Destroy any associated swap
1535 if (backing_object->type == OBJT_SWAP)
1536 swap_pager_freespace(backing_object, p->pindex, 1);
1539 p->pindex < backing_offset_index ||
1540 new_pindex >= object->size
1543 * Page is out of the parent object's range, we
1544 * can simply destroy it.
1546 vm_page_protect(p, VM_PROT_NONE);
1551 pp = vm_page_lookup(object, new_pindex);
1552 if (pp != NULL || vm_pager_has_page(object, new_pindex)) {
1554 * page already exists in parent OR swap exists
1555 * for this location in the parent. Destroy
1556 * the original page from the backing object.
1558 * Leave the parent's page alone
1560 vm_page_protect(p, VM_PROT_NONE);
1566 * Page does not exist in parent, rename the
1567 * page from the backing object to the main object.
1569 * If the page was mapped to a process, it can remain
1570 * mapped through the rename.
1572 if ((p->queue - p->pc) == PQ_CACHE)
1573 vm_page_deactivate(p);
1575 vm_page_rename(p, object, new_pindex);
1576 /* page automatically made dirty by rename */
1582 * This version of collapse allows the operation to occur earlier and
1583 * when paging_in_progress is true for an object... This is not a complete
1584 * operation, but should plug 99.9% of the rest of the leaks.
1586 * The caller must hold vm_token and vmobj_token.
1587 * (only called from vm_object_collapse)
1590 vm_object_qcollapse(vm_object_t object)
1592 vm_object_t backing_object = object->backing_object;
1594 if (backing_object->ref_count != 1)
1597 backing_object->ref_count += 2;
1599 vm_object_backing_scan(object, OBSC_COLLAPSE_NOWAIT);
1601 backing_object->ref_count -= 2;
1605 * Collapse an object with the object backing it. Pages in the backing
1606 * object are moved into the parent, and the backing object is deallocated.
1608 * The caller must hold (object).
1611 vm_object_collapse(vm_object_t object)
1613 ASSERT_LWKT_TOKEN_HELD(&vm_token);
1614 ASSERT_LWKT_TOKEN_HELD(&vmobj_token);
1615 vm_object_assert_held(object);
1618 vm_object_t backing_object;
1621 * Verify that the conditions are right for collapse:
1623 * The object exists and the backing object exists.
1628 if ((backing_object = object->backing_object) == NULL)
1631 vm_object_hold(backing_object);
1632 if (backing_object != object->backing_object) {
1633 vm_object_drop(backing_object);
1638 * we check the backing object first, because it is most likely
1641 if (backing_object->handle != NULL ||
1642 (backing_object->type != OBJT_DEFAULT &&
1643 backing_object->type != OBJT_SWAP) ||
1644 (backing_object->flags & OBJ_DEAD) ||
1645 object->handle != NULL ||
1646 (object->type != OBJT_DEFAULT &&
1647 object->type != OBJT_SWAP) ||
1648 (object->flags & OBJ_DEAD)) {
1649 vm_object_drop(backing_object);
1654 object->paging_in_progress != 0 ||
1655 backing_object->paging_in_progress != 0
1657 vm_object_drop(backing_object);
1658 vm_object_qcollapse(object);
1663 * We know that we can either collapse the backing object (if
1664 * the parent is the only reference to it) or (perhaps) have
1665 * the parent bypass the object if the parent happens to shadow
1666 * all the resident pages in the entire backing object.
1668 * This is ignoring pager-backed pages such as swap pages.
1669 * vm_object_backing_scan fails the shadowing test in this
1673 if (backing_object->ref_count == 1) {
1675 * If there is exactly one reference to the backing
1676 * object, we can collapse it into the parent.
1678 vm_object_backing_scan(object, OBSC_COLLAPSE_WAIT);
1681 * Move the pager from backing_object to object.
1684 if (backing_object->type == OBJT_SWAP) {
1685 vm_object_pip_add(backing_object, 1);
1688 * scrap the paging_offset junk and do a
1689 * discrete copy. This also removes major
1690 * assumptions about how the swap-pager
1691 * works from where it doesn't belong. The
1692 * new swapper is able to optimize the
1693 * destroy-source case.
1696 vm_object_pip_add(object, 1);
1700 OFF_TO_IDX(object->backing_object_offset), TRUE);
1701 vm_object_pip_wakeup(object);
1703 vm_object_pip_wakeup(backing_object);
1706 * Object now shadows whatever backing_object did.
1707 * Note that the reference to
1708 * backing_object->backing_object moves from within
1709 * backing_object to within object.
1712 LIST_REMOVE(object, shadow_list);
1713 object->backing_object->shadow_count--;
1714 object->backing_object->generation++;
1715 if (backing_object->backing_object) {
1716 LIST_REMOVE(backing_object, shadow_list);
1717 backing_object->backing_object->shadow_count--;
1718 backing_object->backing_object->generation++;
1720 object->backing_object = backing_object->backing_object;
1721 if (object->backing_object) {
1723 &object->backing_object->shadow_head,
1727 object->backing_object->shadow_count++;
1728 object->backing_object->generation++;
1731 object->backing_object_offset +=
1732 backing_object->backing_object_offset;
1735 * Discard backing_object.
1737 * Since the backing object has no pages, no pager left,
1738 * and no object references within it, all that is
1739 * necessary is to dispose of it.
1742 KASSERT(backing_object->ref_count == 1,
1743 ("backing_object %p was somehow "
1744 "re-referenced during collapse!",
1746 KASSERT(RB_EMPTY(&backing_object->rb_memq),
1747 ("backing_object %p somehow has left "
1748 "over pages during collapse!",
1752 * Wait for hold count to hit zero
1754 vm_object_drop(backing_object);
1755 vm_object_hold_wait(backing_object);
1757 /* (we are holding vmobj_token) */
1758 TAILQ_REMOVE(&vm_object_list, backing_object,
1760 --backing_object->ref_count; /* safety/debug */
1763 zfree(obj_zone, backing_object);
1767 vm_object_t new_backing_object;
1770 * If we do not entirely shadow the backing object,
1771 * there is nothing we can do so we give up.
1774 if (vm_object_backing_scan(object, OBSC_TEST_ALL_SHADOWED) == 0) {
1775 vm_object_drop(backing_object);
1780 * Make the parent shadow the next object in the
1781 * chain. Deallocating backing_object will not remove
1782 * it, since its reference count is at least 2.
1785 LIST_REMOVE(object, shadow_list);
1786 backing_object->shadow_count--;
1787 backing_object->generation++;
1789 new_backing_object = backing_object->backing_object;
1790 if ((object->backing_object = new_backing_object) != NULL) {
1791 vm_object_reference(new_backing_object);
1793 &new_backing_object->shadow_head,
1797 new_backing_object->shadow_count++;
1798 new_backing_object->generation++;
1799 object->backing_object_offset +=
1800 backing_object->backing_object_offset;
1804 * Drop the reference count on backing_object. Since
1805 * its ref_count was at least 2, it will not vanish;
1806 * so we don't need to call vm_object_deallocate, but
1809 vm_object_drop(backing_object);
1810 vm_object_deallocate_locked(backing_object);
1815 * Try again with this object's new backing object.
1821 * Removes all physical pages in the specified object range from the
1822 * object's list of pages.
1826 static int vm_object_page_remove_callback(vm_page_t p, void *data);
1829 vm_object_page_remove(vm_object_t object, vm_pindex_t start, vm_pindex_t end,
1830 boolean_t clean_only)
1832 struct rb_vm_page_scan_info info;
1836 * Degenerate cases and assertions
1838 lwkt_gettoken(&vm_token);
1839 if (object == NULL ||
1840 (object->resident_page_count == 0 && object->swblock_count == 0)) {
1841 lwkt_reltoken(&vm_token);
1844 KASSERT(object->type != OBJT_PHYS,
1845 ("attempt to remove pages from a physical object"));
1848 * Indicate that paging is occuring on the object
1851 vm_object_pip_add(object, 1);
1854 * Figure out the actual removal range and whether we are removing
1855 * the entire contents of the object or not. If removing the entire
1856 * contents, be sure to get all pages, even those that might be
1857 * beyond the end of the object.
1859 info.start_pindex = start;
1861 info.end_pindex = (vm_pindex_t)-1;
1863 info.end_pindex = end - 1;
1864 info.limit = clean_only;
1865 all = (start == 0 && info.end_pindex >= object->size - 1);
1868 * Loop until we are sure we have gotten them all.
1872 vm_page_rb_tree_RB_SCAN(&object->rb_memq, rb_vm_page_scancmp,
1873 vm_object_page_remove_callback, &info);
1874 } while (info.error);
1877 * Remove any related swap if throwing away pages, or for
1878 * non-swap objects (the swap is a clean copy in that case).
1880 if (object->type != OBJT_SWAP || clean_only == FALSE) {
1882 swap_pager_freespace_all(object);
1884 swap_pager_freespace(object, info.start_pindex,
1885 info.end_pindex - info.start_pindex + 1);
1891 vm_object_pip_wakeup(object);
1893 lwkt_reltoken(&vm_token);
1897 * The caller must hold vm_token.
1900 vm_object_page_remove_callback(vm_page_t p, void *data)
1902 struct rb_vm_page_scan_info *info = data;
1905 * Wired pages cannot be destroyed, but they can be invalidated
1906 * and we do so if clean_only (limit) is not set.
1908 * WARNING! The page may be wired due to being part of a buffer
1909 * cache buffer, and the buffer might be marked B_CACHE.
1910 * This is fine as part of a truncation but VFSs must be
1911 * sure to fix the buffer up when re-extending the file.
1913 if (p->wire_count != 0) {
1914 vm_page_protect(p, VM_PROT_NONE);
1915 if (info->limit == 0)
1921 * The busy flags are only cleared at
1922 * interrupt -- minimize the spl transitions
1925 if (vm_page_sleep_busy(p, TRUE, "vmopar")) {
1931 * limit is our clean_only flag. If set and the page is dirty, do
1932 * not free it. If set and the page is being held by someone, do
1935 if (info->limit && p->valid) {
1936 vm_page_test_dirty(p);
1937 if (p->valid & p->dirty)
1947 vm_page_protect(p, VM_PROT_NONE);
1953 * Coalesces two objects backing up adjoining regions of memory into a
1956 * returns TRUE if objects were combined.
1958 * NOTE: Only works at the moment if the second object is NULL -
1959 * if it's not, which object do we lock first?
1962 * prev_object First object to coalesce
1963 * prev_offset Offset into prev_object
1964 * next_object Second object into coalesce
1965 * next_offset Offset into next_object
1967 * prev_size Size of reference to prev_object
1968 * next_size Size of reference to next_object
1970 * The caller must hold vm_token and vmobj_token.
1972 * The caller does not need to hold (prev_object) but must have a stable
1973 * pointer to it (typically by holding the vm_map locked).
1976 vm_object_coalesce(vm_object_t prev_object, vm_pindex_t prev_pindex,
1977 vm_size_t prev_size, vm_size_t next_size)
1979 vm_pindex_t next_pindex;
1981 ASSERT_LWKT_TOKEN_HELD(&vm_token);
1982 ASSERT_LWKT_TOKEN_HELD(&vmobj_token);
1984 if (prev_object == NULL) {
1988 vm_object_hold(prev_object);
1990 if (prev_object->type != OBJT_DEFAULT &&
1991 prev_object->type != OBJT_SWAP) {
1992 vm_object_drop(prev_object);
1997 * Try to collapse the object first
1999 vm_object_collapse(prev_object);
2002 * Can't coalesce if: . more than one reference . paged out . shadows
2003 * another object . has a copy elsewhere (any of which mean that the
2004 * pages not mapped to prev_entry may be in use anyway)
2007 if (prev_object->backing_object != NULL) {
2008 vm_object_drop(prev_object);
2012 prev_size >>= PAGE_SHIFT;
2013 next_size >>= PAGE_SHIFT;
2014 next_pindex = prev_pindex + prev_size;
2016 if ((prev_object->ref_count > 1) &&
2017 (prev_object->size != next_pindex)) {
2018 vm_object_drop(prev_object);
2023 * Remove any pages that may still be in the object from a previous
2026 if (next_pindex < prev_object->size) {
2027 vm_object_page_remove(prev_object,
2029 next_pindex + next_size, FALSE);
2030 if (prev_object->type == OBJT_SWAP)
2031 swap_pager_freespace(prev_object,
2032 next_pindex, next_size);
2036 * Extend the object if necessary.
2038 if (next_pindex + next_size > prev_object->size)
2039 prev_object->size = next_pindex + next_size;
2041 vm_object_drop(prev_object);
2046 * Make the object writable and flag is being possibly dirty.
2051 vm_object_set_writeable_dirty(vm_object_t object)
2055 lwkt_gettoken(&vm_token);
2056 vm_object_set_flag(object, OBJ_WRITEABLE|OBJ_MIGHTBEDIRTY);
2057 if (object->type == OBJT_VNODE &&
2058 (vp = (struct vnode *)object->handle) != NULL) {
2059 if ((vp->v_flag & VOBJDIRTY) == 0) {
2060 vsetflags(vp, VOBJDIRTY);
2063 lwkt_reltoken(&vm_token);
2066 #include "opt_ddb.h"
2068 #include <sys/kernel.h>
2070 #include <sys/cons.h>
2072 #include <ddb/ddb.h>
2074 static int _vm_object_in_map (vm_map_t map, vm_object_t object,
2075 vm_map_entry_t entry);
2076 static int vm_object_in_map (vm_object_t object);
2079 * The caller must hold vm_token.
2082 _vm_object_in_map(vm_map_t map, vm_object_t object, vm_map_entry_t entry)
2085 vm_map_entry_t tmpe;
2092 tmpe = map->header.next;
2093 entcount = map->nentries;
2094 while (entcount-- && (tmpe != &map->header)) {
2095 if( _vm_object_in_map(map, object, tmpe)) {
2102 switch(entry->maptype) {
2103 case VM_MAPTYPE_SUBMAP:
2104 tmpm = entry->object.sub_map;
2105 tmpe = tmpm->header.next;
2106 entcount = tmpm->nentries;
2107 while (entcount-- && tmpe != &tmpm->header) {
2108 if( _vm_object_in_map(tmpm, object, tmpe)) {
2114 case VM_MAPTYPE_NORMAL:
2115 case VM_MAPTYPE_VPAGETABLE:
2116 obj = entry->object.vm_object;
2120 obj = obj->backing_object;
2129 static int vm_object_in_map_callback(struct proc *p, void *data);
2131 struct vm_object_in_map_info {
2140 vm_object_in_map(vm_object_t object)
2142 struct vm_object_in_map_info info;
2145 info.object = object;
2147 allproc_scan(vm_object_in_map_callback, &info);
2150 if( _vm_object_in_map(&kernel_map, object, 0))
2152 if( _vm_object_in_map(&pager_map, object, 0))
2154 if( _vm_object_in_map(&buffer_map, object, 0))
2163 vm_object_in_map_callback(struct proc *p, void *data)
2165 struct vm_object_in_map_info *info = data;
2168 if (_vm_object_in_map(&p->p_vmspace->vm_map, info->object, 0)) {
2176 DB_SHOW_COMMAND(vmochk, vm_object_check)
2181 * make sure that internal objs are in a map somewhere
2182 * and none have zero ref counts.
2184 for (object = TAILQ_FIRST(&vm_object_list);
2186 object = TAILQ_NEXT(object, object_list)) {
2187 if (object->type == OBJT_MARKER)
2189 if (object->handle == NULL &&
2190 (object->type == OBJT_DEFAULT || object->type == OBJT_SWAP)) {
2191 if (object->ref_count == 0) {
2192 db_printf("vmochk: internal obj has zero ref count: %ld\n",
2193 (long)object->size);
2195 if (!vm_object_in_map(object)) {
2197 "vmochk: internal obj is not in a map: "
2198 "ref: %d, size: %lu: 0x%lx, backing_object: %p\n",
2199 object->ref_count, (u_long)object->size,
2200 (u_long)object->size,
2201 (void *)object->backing_object);
2210 DB_SHOW_COMMAND(object, vm_object_print_static)
2212 /* XXX convert args. */
2213 vm_object_t object = (vm_object_t)addr;
2214 boolean_t full = have_addr;
2218 /* XXX count is an (unused) arg. Avoid shadowing it. */
2219 #define count was_count
2227 "Object %p: type=%d, size=0x%lx, res=%d, ref=%d, flags=0x%x\n",
2228 object, (int)object->type, (u_long)object->size,
2229 object->resident_page_count, object->ref_count, object->flags);
2231 * XXX no %qd in kernel. Truncate object->backing_object_offset.
2233 db_iprintf(" sref=%d, backing_object(%d)=(%p)+0x%lx\n",
2234 object->shadow_count,
2235 object->backing_object ? object->backing_object->ref_count : 0,
2236 object->backing_object, (long)object->backing_object_offset);
2243 RB_FOREACH(p, vm_page_rb_tree, &object->rb_memq) {
2245 db_iprintf("memory:=");
2246 else if (count == 6) {
2254 db_printf("(off=0x%lx,page=0x%lx)",
2255 (u_long) p->pindex, (u_long) VM_PAGE_TO_PHYS(p));
2266 * XXX need this non-static entry for calling from vm_map_print.
2271 vm_object_print(/* db_expr_t */ long addr,
2272 boolean_t have_addr,
2273 /* db_expr_t */ long count,
2276 vm_object_print_static(addr, have_addr, count, modif);
2282 DB_SHOW_COMMAND(vmopag, vm_object_print_pages)
2287 for (object = TAILQ_FIRST(&vm_object_list);
2289 object = TAILQ_NEXT(object, object_list)) {
2290 vm_pindex_t idx, fidx;
2292 vm_paddr_t pa = -1, padiff;
2296 if (object->type == OBJT_MARKER)
2298 db_printf("new object: %p\n", (void *)object);
2308 osize = object->size;
2311 for (idx = 0; idx < osize; idx++) {
2312 m = vm_page_lookup(object, idx);
2315 db_printf(" index(%ld)run(%d)pa(0x%lx)\n",
2316 (long)fidx, rcount, (long)pa);
2331 (VM_PAGE_TO_PHYS(m) == pa + rcount * PAGE_SIZE)) {
2336 padiff = pa + rcount * PAGE_SIZE - VM_PAGE_TO_PHYS(m);
2337 padiff >>= PAGE_SHIFT;
2338 padiff &= PQ_L2_MASK;
2340 pa = VM_PAGE_TO_PHYS(m) - rcount * PAGE_SIZE;
2344 db_printf(" index(%ld)run(%d)pa(0x%lx)",
2345 (long)fidx, rcount, (long)pa);
2346 db_printf("pd(%ld)\n", (long)padiff);
2356 pa = VM_PAGE_TO_PHYS(m);
2360 db_printf(" index(%ld)run(%d)pa(0x%lx)\n",
2361 (long)fidx, rcount, (long)pa);