FreeBSD/Linux Kernel Cross Reference
sys/vm/vm_object.c
1 /*-
2 * Copyright (c) 1991, 1993
3 * The Regents of the University of California. All rights reserved.
4 *
5 * This code is derived from software contributed to Berkeley by
6 * The Mach Operating System project at Carnegie-Mellon University.
7 *
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted provided that the following conditions
10 * are met:
11 * 1. Redistributions of source code must retain the above copyright
12 * notice, this list of conditions and the following disclaimer.
13 * 2. Redistributions in binary form must reproduce the above copyright
14 * notice, this list of conditions and the following disclaimer in the
15 * documentation and/or other materials provided with the distribution.
16 * 4. Neither the name of the University nor the names of its contributors
17 * may be used to endorse or promote products derived from this software
18 * without specific prior written permission.
19 *
20 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
21 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
22 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
23 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
24 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
25 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
26 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
27 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
28 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
29 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
30 * SUCH DAMAGE.
31 *
32 * from: @(#)vm_object.c 8.5 (Berkeley) 3/22/94
33 *
34 *
35 * Copyright (c) 1987, 1990 Carnegie-Mellon University.
36 * All rights reserved.
37 *
38 * Authors: Avadis Tevanian, Jr., Michael Wayne Young
39 *
40 * Permission to use, copy, modify and distribute this software and
41 * its documentation is hereby granted, provided that both the copyright
42 * notice and this permission notice appear in all copies of the
43 * software, derivative works or modified versions, and any portions
44 * thereof, and that both notices appear in supporting documentation.
45 *
46 * CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS"
47 * CONDITION. CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND
48 * FOR ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
49 *
50 * Carnegie Mellon requests users of this software to return to
51 *
52 * Software Distribution Coordinator or Software.Distribution@CS.CMU.EDU
53 * School of Computer Science
54 * Carnegie Mellon University
55 * Pittsburgh PA 15213-3890
56 *
57 * any improvements or extensions that they make and grant Carnegie the
58 * rights to redistribute these changes.
59 */
60
61 /*
62 * Virtual memory object module.
63 */
64
65 #include <sys/cdefs.h>
66 __FBSDID("$FreeBSD: src/sys/vm/vm_object.c,v 1.331.2.5 2005/08/15 14:59:53 tegge Exp $");
67
68 #include <sys/param.h>
69 #include <sys/systm.h>
70 #include <sys/lock.h>
71 #include <sys/mman.h>
72 #include <sys/mount.h>
73 #include <sys/kernel.h>
74 #include <sys/sysctl.h>
75 #include <sys/mutex.h>
76 #include <sys/proc.h> /* for curproc, pageproc */
77 #include <sys/socket.h>
78 #include <sys/vnode.h>
79 #include <sys/vmmeter.h>
80 #include <sys/sx.h>
81
82 #include <vm/vm.h>
83 #include <vm/vm_param.h>
84 #include <vm/pmap.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/uma.h>
94
95 #define EASY_SCAN_FACTOR 8
96
97 #define MSYNC_FLUSH_HARDSEQ 0x01
98 #define MSYNC_FLUSH_SOFTSEQ 0x02
99
100 /*
101 * msync / VM object flushing optimizations
102 */
103 static int msync_flush_flags = MSYNC_FLUSH_HARDSEQ | MSYNC_FLUSH_SOFTSEQ;
104 SYSCTL_INT(_vm, OID_AUTO, msync_flush_flags,
105 CTLFLAG_RW, &msync_flush_flags, 0, "");
106
107 static int old_msync;
108 SYSCTL_INT(_vm, OID_AUTO, old_msync, CTLFLAG_RW, &old_msync, 0,
109 "Use old (insecure) msync behavior");
110
111 static void vm_object_qcollapse(vm_object_t object);
112 static int vm_object_page_collect_flush(vm_object_t object, vm_page_t p, int curgeneration, int pagerflags);
113
114 /*
115 * Virtual memory objects maintain the actual data
116 * associated with allocated virtual memory. A given
117 * page of memory exists within exactly one object.
118 *
119 * An object is only deallocated when all "references"
120 * are given up. Only one "reference" to a given
121 * region of an object should be writeable.
122 *
123 * Associated with each object is a list of all resident
124 * memory pages belonging to that object; this list is
125 * maintained by the "vm_page" module, and locked by the object's
126 * lock.
127 *
128 * Each object also records a "pager" routine which is
129 * used to retrieve (and store) pages to the proper backing
130 * storage. In addition, objects may be backed by other
131 * objects from which they were virtual-copied.
132 *
133 * The only items within the object structure which are
134 * modified after time of creation are:
135 * reference count locked by object's lock
136 * pager routine locked by object's lock
137 *
138 */
139
140 struct object_q vm_object_list;
141 struct mtx vm_object_list_mtx; /* lock for object list and count */
142
143 struct vm_object kernel_object_store;
144 struct vm_object kmem_object_store;
145
146 static long object_collapses;
147 static long object_bypasses;
148
149 /*
150 * next_index determines the page color that is assigned to the next
151 * allocated object. Accesses to next_index are not synchronized
152 * because the effects of two or more object allocations using
153 * next_index simultaneously are inconsequential. At any given time,
154 * numerous objects have the same page color.
155 */
156 static int next_index;
157
158 static uma_zone_t obj_zone;
159 #define VM_OBJECTS_INIT 256
160
161 static int vm_object_zinit(void *mem, int size, int flags);
162
163 #ifdef INVARIANTS
164 static void vm_object_zdtor(void *mem, int size, void *arg);
165
166 static void
167 vm_object_zdtor(void *mem, int size, void *arg)
168 {
169 vm_object_t object;
170
171 object = (vm_object_t)mem;
172 KASSERT(TAILQ_EMPTY(&object->memq),
173 ("object %p has resident pages",
174 object));
175 KASSERT(object->paging_in_progress == 0,
176 ("object %p paging_in_progress = %d",
177 object, object->paging_in_progress));
178 KASSERT(object->resident_page_count == 0,
179 ("object %p resident_page_count = %d",
180 object, object->resident_page_count));
181 KASSERT(object->shadow_count == 0,
182 ("object %p shadow_count = %d",
183 object, object->shadow_count));
184 }
185 #endif
186
187 static int
188 vm_object_zinit(void *mem, int size, int flags)
189 {
190 vm_object_t object;
191
192 object = (vm_object_t)mem;
193 bzero(&object->mtx, sizeof(object->mtx));
194 VM_OBJECT_LOCK_INIT(object, "standard object");
195
196 /* These are true for any object that has been freed */
197 object->paging_in_progress = 0;
198 object->resident_page_count = 0;
199 object->shadow_count = 0;
200 return (0);
201 }
202
203 void
204 _vm_object_allocate(objtype_t type, vm_pindex_t size, vm_object_t object)
205 {
206 int incr;
207
208 TAILQ_INIT(&object->memq);
209 LIST_INIT(&object->shadow_head);
210
211 object->root = NULL;
212 object->type = type;
213 object->size = size;
214 object->generation = 1;
215 object->ref_count = 1;
216 object->flags = 0;
217 if ((object->type == OBJT_DEFAULT) || (object->type == OBJT_SWAP))
218 object->flags = OBJ_ONEMAPPING;
219 if (size > (PQ_L2_SIZE / 3 + PQ_PRIME1))
220 incr = PQ_L2_SIZE / 3 + PQ_PRIME1;
221 else
222 incr = size;
223 object->pg_color = next_index;
224 next_index = (object->pg_color + incr) & PQ_L2_MASK;
225 object->handle = NULL;
226 object->backing_object = NULL;
227 object->backing_object_offset = (vm_ooffset_t) 0;
228
229 mtx_lock(&vm_object_list_mtx);
230 TAILQ_INSERT_TAIL(&vm_object_list, object, object_list);
231 mtx_unlock(&vm_object_list_mtx);
232 }
233
234 /*
235 * vm_object_init:
236 *
237 * Initialize the VM objects module.
238 */
239 void
240 vm_object_init(void)
241 {
242 TAILQ_INIT(&vm_object_list);
243 mtx_init(&vm_object_list_mtx, "vm object_list", NULL, MTX_DEF);
244
245 VM_OBJECT_LOCK_INIT(&kernel_object_store, "kernel object");
246 _vm_object_allocate(OBJT_DEFAULT, OFF_TO_IDX(VM_MAX_KERNEL_ADDRESS - VM_MIN_KERNEL_ADDRESS),
247 kernel_object);
248
249 VM_OBJECT_LOCK_INIT(&kmem_object_store, "kmem object");
250 _vm_object_allocate(OBJT_DEFAULT, OFF_TO_IDX(VM_MAX_KERNEL_ADDRESS - VM_MIN_KERNEL_ADDRESS),
251 kmem_object);
252
253 /*
254 * The lock portion of struct vm_object must be type stable due
255 * to vm_pageout_fallback_object_lock locking a vm object
256 * without holding any references to it.
257 */
258 obj_zone = uma_zcreate("VM OBJECT", sizeof (struct vm_object), NULL,
259 #ifdef INVARIANTS
260 vm_object_zdtor,
261 #else
262 NULL,
263 #endif
264 vm_object_zinit, NULL, UMA_ALIGN_PTR, UMA_ZONE_VM|UMA_ZONE_NOFREE);
265 uma_prealloc(obj_zone, VM_OBJECTS_INIT);
266 }
267
268 void
269 vm_object_clear_flag(vm_object_t object, u_short bits)
270 {
271
272 VM_OBJECT_LOCK_ASSERT(object, MA_OWNED);
273 object->flags &= ~bits;
274 }
275
276 void
277 vm_object_pip_add(vm_object_t object, short i)
278 {
279
280 VM_OBJECT_LOCK_ASSERT(object, MA_OWNED);
281 object->paging_in_progress += i;
282 }
283
284 void
285 vm_object_pip_subtract(vm_object_t object, short i)
286 {
287
288 VM_OBJECT_LOCK_ASSERT(object, MA_OWNED);
289 object->paging_in_progress -= i;
290 }
291
292 void
293 vm_object_pip_wakeup(vm_object_t object)
294 {
295
296 VM_OBJECT_LOCK_ASSERT(object, MA_OWNED);
297 object->paging_in_progress--;
298 if ((object->flags & OBJ_PIPWNT) && object->paging_in_progress == 0) {
299 vm_object_clear_flag(object, OBJ_PIPWNT);
300 wakeup(object);
301 }
302 }
303
304 void
305 vm_object_pip_wakeupn(vm_object_t object, short i)
306 {
307
308 VM_OBJECT_LOCK_ASSERT(object, MA_OWNED);
309 if (i)
310 object->paging_in_progress -= i;
311 if ((object->flags & OBJ_PIPWNT) && object->paging_in_progress == 0) {
312 vm_object_clear_flag(object, OBJ_PIPWNT);
313 wakeup(object);
314 }
315 }
316
317 void
318 vm_object_pip_wait(vm_object_t object, char *waitid)
319 {
320
321 VM_OBJECT_LOCK_ASSERT(object, MA_OWNED);
322 while (object->paging_in_progress) {
323 object->flags |= OBJ_PIPWNT;
324 msleep(object, VM_OBJECT_MTX(object), PVM, waitid, 0);
325 }
326 }
327
328 /*
329 * vm_object_allocate_wait
330 *
331 * Return a new object with the given size, and give the user the
332 * option of waiting for it to complete or failing if the needed
333 * memory isn't available.
334 */
335 vm_object_t
336 vm_object_allocate_wait(objtype_t type, vm_pindex_t size, int flags)
337 {
338 vm_object_t result;
339
340 result = (vm_object_t) uma_zalloc(obj_zone, flags);
341
342 if (result != NULL)
343 _vm_object_allocate(type, size, result);
344
345 return (result);
346 }
347
348 /*
349 * vm_object_allocate:
350 *
351 * Returns a new object with the given size.
352 */
353 vm_object_t
354 vm_object_allocate(objtype_t type, vm_pindex_t size)
355 {
356 return(vm_object_allocate_wait(type, size, M_WAITOK));
357 }
358
359
360 /*
361 * vm_object_reference:
362 *
363 * Gets another reference to the given object. Note: OBJ_DEAD
364 * objects can be referenced during final cleaning.
365 */
366 void
367 vm_object_reference(vm_object_t object)
368 {
369 struct vnode *vp;
370 int flags;
371
372 if (object == NULL)
373 return;
374 VM_OBJECT_LOCK(object);
375 object->ref_count++;
376 if (object->type == OBJT_VNODE) {
377 vp = object->handle;
378 VI_LOCK(vp);
379 VM_OBJECT_UNLOCK(object);
380 for (flags = LK_INTERLOCK; vget(vp, flags, curthread);
381 flags = 0)
382 printf("vm_object_reference: delay in vget\n");
383 } else
384 VM_OBJECT_UNLOCK(object);
385 }
386
387 /*
388 * vm_object_reference_locked:
389 *
390 * Gets another reference to the given object.
391 *
392 * The object must be locked.
393 */
394 void
395 vm_object_reference_locked(vm_object_t object)
396 {
397 struct vnode *vp;
398
399 VM_OBJECT_LOCK_ASSERT(object, MA_OWNED);
400 KASSERT((object->flags & OBJ_DEAD) == 0,
401 ("vm_object_reference_locked: dead object referenced"));
402 object->ref_count++;
403 if (object->type == OBJT_VNODE) {
404 vp = object->handle;
405 vref(vp);
406 }
407 }
408
409 /*
410 * Handle deallocating an object of type OBJT_VNODE.
411 */
412 void
413 vm_object_vndeallocate(vm_object_t object)
414 {
415 struct vnode *vp = (struct vnode *) object->handle;
416
417 GIANT_REQUIRED;
418 VM_OBJECT_LOCK_ASSERT(object, MA_OWNED);
419 KASSERT(object->type == OBJT_VNODE,
420 ("vm_object_vndeallocate: not a vnode object"));
421 KASSERT(vp != NULL, ("vm_object_vndeallocate: missing vp"));
422 #ifdef INVARIANTS
423 if (object->ref_count == 0) {
424 vprint("vm_object_vndeallocate", vp);
425 panic("vm_object_vndeallocate: bad object reference count");
426 }
427 #endif
428
429 object->ref_count--;
430 if (object->ref_count == 0) {
431 mp_fixme("Unlocked vflag access.");
432 vp->v_vflag &= ~VV_TEXT;
433 }
434 VM_OBJECT_UNLOCK(object);
435 /*
436 * vrele may need a vop lock
437 */
438 vrele(vp);
439 }
440
441 /*
442 * vm_object_deallocate:
443 *
444 * Release a reference to the specified object,
445 * gained either through a vm_object_allocate
446 * or a vm_object_reference call. When all references
447 * are gone, storage associated with this object
448 * may be relinquished.
449 *
450 * No object may be locked.
451 */
452 void
453 vm_object_deallocate(vm_object_t object)
454 {
455 vm_object_t temp;
456
457 while (object != NULL) {
458 /*
459 * In general, the object should be locked when working with
460 * its type. In this case, in order to maintain proper lock
461 * ordering, an exception is possible because a vnode-backed
462 * object never changes its type.
463 */
464 if (object->type == OBJT_VNODE)
465 mtx_lock(&Giant);
466 VM_OBJECT_LOCK(object);
467 if (object->type == OBJT_VNODE) {
468 vm_object_vndeallocate(object);
469 mtx_unlock(&Giant);
470 return;
471 }
472
473 KASSERT(object->ref_count != 0,
474 ("vm_object_deallocate: object deallocated too many times: %d", object->type));
475
476 /*
477 * If the reference count goes to 0 we start calling
478 * vm_object_terminate() on the object chain.
479 * A ref count of 1 may be a special case depending on the
480 * shadow count being 0 or 1.
481 */
482 object->ref_count--;
483 if (object->ref_count > 1) {
484 VM_OBJECT_UNLOCK(object);
485 return;
486 } else if (object->ref_count == 1) {
487 if (object->shadow_count == 0) {
488 vm_object_set_flag(object, OBJ_ONEMAPPING);
489 } else if ((object->shadow_count == 1) &&
490 (object->handle == NULL) &&
491 (object->type == OBJT_DEFAULT ||
492 object->type == OBJT_SWAP)) {
493 vm_object_t robject;
494
495 robject = LIST_FIRST(&object->shadow_head);
496 KASSERT(robject != NULL,
497 ("vm_object_deallocate: ref_count: %d, shadow_count: %d",
498 object->ref_count,
499 object->shadow_count));
500 if (!VM_OBJECT_TRYLOCK(robject)) {
501 /*
502 * Avoid a potential deadlock.
503 */
504 object->ref_count++;
505 VM_OBJECT_UNLOCK(object);
506 /*
507 * More likely than not the thread
508 * holding robject's lock has lower
509 * priority than the current thread.
510 * Let the lower priority thread run.
511 */
512 tsleep(&proc0, PVM, "vmo_de", 1);
513 continue;
514 }
515 /*
516 * Collapse object into its shadow unless its
517 * shadow is dead. In that case, object will
518 * be deallocated by the thread that is
519 * deallocating its shadow.
520 */
521 if ((robject->flags & OBJ_DEAD) == 0 &&
522 (robject->handle == NULL) &&
523 (robject->type == OBJT_DEFAULT ||
524 robject->type == OBJT_SWAP)) {
525
526 robject->ref_count++;
527 retry:
528 if (robject->paging_in_progress) {
529 VM_OBJECT_UNLOCK(object);
530 vm_object_pip_wait(robject,
531 "objde1");
532 VM_OBJECT_LOCK(object);
533 goto retry;
534 } else if (object->paging_in_progress) {
535 VM_OBJECT_UNLOCK(robject);
536 object->flags |= OBJ_PIPWNT;
537 msleep(object,
538 VM_OBJECT_MTX(object),
539 PDROP | PVM, "objde2", 0);
540 VM_OBJECT_LOCK(robject);
541 VM_OBJECT_LOCK(object);
542 goto retry;
543 }
544 VM_OBJECT_UNLOCK(object);
545 if (robject->ref_count == 1) {
546 robject->ref_count--;
547 object = robject;
548 goto doterm;
549 }
550 object = robject;
551 vm_object_collapse(object);
552 VM_OBJECT_UNLOCK(object);
553 continue;
554 }
555 VM_OBJECT_UNLOCK(robject);
556 }
557 VM_OBJECT_UNLOCK(object);
558 return;
559 }
560 doterm:
561 temp = object->backing_object;
562 if (temp != NULL) {
563 VM_OBJECT_LOCK(temp);
564 LIST_REMOVE(object, shadow_list);
565 temp->shadow_count--;
566 temp->generation++;
567 VM_OBJECT_UNLOCK(temp);
568 object->backing_object = NULL;
569 }
570 /*
571 * Don't double-terminate, we could be in a termination
572 * recursion due to the terminate having to sync data
573 * to disk.
574 */
575 if ((object->flags & OBJ_DEAD) == 0)
576 vm_object_terminate(object);
577 else
578 VM_OBJECT_UNLOCK(object);
579 object = temp;
580 }
581 }
582
583 /*
584 * vm_object_terminate actually destroys the specified object, freeing
585 * up all previously used resources.
586 *
587 * The object must be locked.
588 * This routine may block.
589 */
590 void
591 vm_object_terminate(vm_object_t object)
592 {
593 vm_page_t p;
594
595 VM_OBJECT_LOCK_ASSERT(object, MA_OWNED);
596
597 /*
598 * Make sure no one uses us.
599 */
600 vm_object_set_flag(object, OBJ_DEAD);
601
602 /*
603 * wait for the pageout daemon to be done with the object
604 */
605 vm_object_pip_wait(object, "objtrm");
606
607 KASSERT(!object->paging_in_progress,
608 ("vm_object_terminate: pageout in progress"));
609
610 /*
611 * Clean and free the pages, as appropriate. All references to the
612 * object are gone, so we don't need to lock it.
613 */
614 if (object->type == OBJT_VNODE) {
615 struct vnode *vp = (struct vnode *)object->handle;
616
617 /*
618 * Clean pages and flush buffers.
619 */
620 vm_object_page_clean(object, 0, 0, OBJPC_SYNC);
621 VM_OBJECT_UNLOCK(object);
622
623 vinvalbuf(vp, V_SAVE, NOCRED, NULL, 0, 0);
624
625 VM_OBJECT_LOCK(object);
626 }
627
628 KASSERT(object->ref_count == 0,
629 ("vm_object_terminate: object with references, ref_count=%d",
630 object->ref_count));
631
632 /*
633 * Now free any remaining pages. For internal objects, this also
634 * removes them from paging queues. Don't free wired pages, just
635 * remove them from the object.
636 */
637 vm_page_lock_queues();
638 while ((p = TAILQ_FIRST(&object->memq)) != NULL) {
639 KASSERT(!p->busy && (p->flags & PG_BUSY) == 0,
640 ("vm_object_terminate: freeing busy page %p "
641 "p->busy = %d, p->flags %x\n", p, p->busy, p->flags));
642 if (p->wire_count == 0) {
643 vm_page_free(p);
644 cnt.v_pfree++;
645 } else {
646 vm_page_remove(p);
647 }
648 }
649 vm_page_unlock_queues();
650
651 /*
652 * Let the pager know object is dead.
653 */
654 vm_pager_deallocate(object);
655 VM_OBJECT_UNLOCK(object);
656
657 /*
658 * Remove the object from the global object list.
659 */
660 mtx_lock(&vm_object_list_mtx);
661 TAILQ_REMOVE(&vm_object_list, object, object_list);
662 mtx_unlock(&vm_object_list_mtx);
663
664 /*
665 * Free the space for the object.
666 */
667 uma_zfree(obj_zone, object);
668 }
669
670 /*
671 * vm_object_page_clean
672 *
673 * Clean all dirty pages in the specified range of object. Leaves page
674 * on whatever queue it is currently on. If NOSYNC is set then do not
675 * write out pages with PG_NOSYNC set (originally comes from MAP_NOSYNC),
676 * leaving the object dirty.
677 *
678 * When stuffing pages asynchronously, allow clustering. XXX we need a
679 * synchronous clustering mode implementation.
680 *
681 * Odd semantics: if start == end, we clean everything.
682 *
683 * The object must be locked.
684 */
685 void
686 vm_object_page_clean(vm_object_t object, vm_pindex_t start, vm_pindex_t end, int flags)
687 {
688 vm_page_t p, np;
689 vm_pindex_t tstart, tend;
690 vm_pindex_t pi;
691 int clearobjflags;
692 int pagerflags;
693 int curgeneration;
694
695 GIANT_REQUIRED;
696 VM_OBJECT_LOCK_ASSERT(object, MA_OWNED);
697 if (object->type != OBJT_VNODE ||
698 (object->flags & OBJ_MIGHTBEDIRTY) == 0)
699 return;
700
701 pagerflags = (flags & (OBJPC_SYNC | OBJPC_INVAL)) ? VM_PAGER_PUT_SYNC : VM_PAGER_CLUSTER_OK;
702 pagerflags |= (flags & OBJPC_INVAL) ? VM_PAGER_PUT_INVAL : 0;
703
704 vm_object_set_flag(object, OBJ_CLEANING);
705
706 tstart = start;
707 if (end == 0) {
708 tend = object->size;
709 } else {
710 tend = end;
711 }
712
713 vm_page_lock_queues();
714 /*
715 * If the caller is smart and only msync()s a range he knows is
716 * dirty, we may be able to avoid an object scan. This results in
717 * a phenominal improvement in performance. We cannot do this
718 * as a matter of course because the object may be huge - e.g.
719 * the size might be in the gigabytes or terrabytes.
720 */
721 if (msync_flush_flags & MSYNC_FLUSH_HARDSEQ) {
722 vm_pindex_t tscan;
723 int scanlimit;
724 int scanreset;
725
726 scanreset = object->resident_page_count / EASY_SCAN_FACTOR;
727 if (scanreset < 16)
728 scanreset = 16;
729 pagerflags |= VM_PAGER_IGNORE_CLEANCHK;
730
731 scanlimit = scanreset;
732 tscan = tstart;
733 while (tscan < tend) {
734 curgeneration = object->generation;
735 p = vm_page_lookup(object, tscan);
736 if (p == NULL || p->valid == 0 ||
737 (p->queue - p->pc) == PQ_CACHE) {
738 if (--scanlimit == 0)
739 break;
740 ++tscan;
741 continue;
742 }
743 vm_page_test_dirty(p);
744 if ((p->dirty & p->valid) == 0) {
745 if (--scanlimit == 0)
746 break;
747 ++tscan;
748 continue;
749 }
750 /*
751 * If we have been asked to skip nosync pages and
752 * this is a nosync page, we can't continue.
753 */
754 if ((flags & OBJPC_NOSYNC) && (p->flags & PG_NOSYNC)) {
755 if (--scanlimit == 0)
756 break;
757 ++tscan;
758 continue;
759 }
760 scanlimit = scanreset;
761
762 /*
763 * This returns 0 if it was unable to busy the first
764 * page (i.e. had to sleep).
765 */
766 tscan += vm_object_page_collect_flush(object, p, curgeneration, pagerflags);
767 }
768
769 /*
770 * If everything was dirty and we flushed it successfully,
771 * and the requested range is not the entire object, we
772 * don't have to mess with CLEANCHK or MIGHTBEDIRTY and can
773 * return immediately.
774 */
775 if (tscan >= tend && (tstart || tend < object->size)) {
776 vm_page_unlock_queues();
777 vm_object_clear_flag(object, OBJ_CLEANING);
778 return;
779 }
780 pagerflags &= ~VM_PAGER_IGNORE_CLEANCHK;
781 }
782
783 /*
784 * Generally set CLEANCHK interlock and make the page read-only so
785 * we can then clear the object flags.
786 *
787 * However, if this is a nosync mmap then the object is likely to
788 * stay dirty so do not mess with the page and do not clear the
789 * object flags.
790 */
791 clearobjflags = 1;
792 TAILQ_FOREACH(p, &object->memq, listq) {
793 vm_page_flag_set(p, PG_CLEANCHK);
794 if ((flags & OBJPC_NOSYNC) && (p->flags & PG_NOSYNC))
795 clearobjflags = 0;
796 else
797 pmap_page_protect(p, VM_PROT_READ);
798 }
799
800 if (clearobjflags && (tstart == 0) && (tend == object->size)) {
801 struct vnode *vp;
802
803 vm_object_clear_flag(object, OBJ_WRITEABLE|OBJ_MIGHTBEDIRTY);
804 if (object->type == OBJT_VNODE &&
805 (vp = (struct vnode *)object->handle) != NULL) {
806 VI_LOCK(vp);
807 if (vp->v_iflag & VI_OBJDIRTY)
808 vp->v_iflag &= ~VI_OBJDIRTY;
809 VI_UNLOCK(vp);
810 }
811 }
812
813 rescan:
814 curgeneration = object->generation;
815
816 for (p = TAILQ_FIRST(&object->memq); p; p = np) {
817 int n;
818
819 np = TAILQ_NEXT(p, listq);
820
821 again:
822 pi = p->pindex;
823 if (((p->flags & PG_CLEANCHK) == 0) ||
824 (pi < tstart) || (pi >= tend) ||
825 (p->valid == 0) ||
826 ((p->queue - p->pc) == PQ_CACHE)) {
827 vm_page_flag_clear(p, PG_CLEANCHK);
828 continue;
829 }
830
831 vm_page_test_dirty(p);
832 if ((p->dirty & p->valid) == 0) {
833 vm_page_flag_clear(p, PG_CLEANCHK);
834 continue;
835 }
836
837 /*
838 * If we have been asked to skip nosync pages and this is a
839 * nosync page, skip it. Note that the object flags were
840 * not cleared in this case so we do not have to set them.
841 */
842 if ((flags & OBJPC_NOSYNC) && (p->flags & PG_NOSYNC)) {
843 vm_page_flag_clear(p, PG_CLEANCHK);
844 continue;
845 }
846
847 n = vm_object_page_collect_flush(object, p,
848 curgeneration, pagerflags);
849 if (n == 0)
850 goto rescan;
851
852 if (object->generation != curgeneration)
853 goto rescan;
854
855 /*
856 * Try to optimize the next page. If we can't we pick up
857 * our (random) scan where we left off.
858 */
859 if (msync_flush_flags & MSYNC_FLUSH_SOFTSEQ) {
860 if ((p = vm_page_lookup(object, pi + n)) != NULL)
861 goto again;
862 }
863 }
864 vm_page_unlock_queues();
865 #if 0
866 VOP_FSYNC(vp, NULL, (pagerflags & VM_PAGER_PUT_SYNC)?MNT_WAIT:0, curproc);
867 #endif
868
869 vm_object_clear_flag(object, OBJ_CLEANING);
870 return;
871 }
872
873 static int
874 vm_object_page_collect_flush(vm_object_t object, vm_page_t p, int curgeneration, int pagerflags)
875 {
876 int runlen;
877 int maxf;
878 int chkb;
879 int maxb;
880 int i;
881 vm_pindex_t pi;
882 vm_page_t maf[vm_pageout_page_count];
883 vm_page_t mab[vm_pageout_page_count];
884 vm_page_t ma[vm_pageout_page_count];
885
886 mtx_assert(&vm_page_queue_mtx, MA_OWNED);
887 pi = p->pindex;
888 while (vm_page_sleep_if_busy(p, TRUE, "vpcwai")) {
889 vm_page_lock_queues();
890 if (object->generation != curgeneration) {
891 return(0);
892 }
893 }
894 maxf = 0;
895 for(i = 1; i < vm_pageout_page_count; i++) {
896 vm_page_t tp;
897
898 if ((tp = vm_page_lookup(object, pi + i)) != NULL) {
899 if ((tp->flags & PG_BUSY) ||
900 ((pagerflags & VM_PAGER_IGNORE_CLEANCHK) == 0 &&
901 (tp->flags & PG_CLEANCHK) == 0) ||
902 (tp->busy != 0))
903 break;
904 if((tp->queue - tp->pc) == PQ_CACHE) {
905 vm_page_flag_clear(tp, PG_CLEANCHK);
906 break;
907 }
908 vm_page_test_dirty(tp);
909 if ((tp->dirty & tp->valid) == 0) {
910 vm_page_flag_clear(tp, PG_CLEANCHK);
911 break;
912 }
913 maf[ i - 1 ] = tp;
914 maxf++;
915 continue;
916 }
917 break;
918 }
919
920 maxb = 0;
921 chkb = vm_pageout_page_count - maxf;
922 if (chkb) {
923 for(i = 1; i < chkb;i++) {
924 vm_page_t tp;
925
926 if ((tp = vm_page_lookup(object, pi - i)) != NULL) {
927 if ((tp->flags & PG_BUSY) ||
928 ((pagerflags & VM_PAGER_IGNORE_CLEANCHK) == 0 &&
929 (tp->flags & PG_CLEANCHK) == 0) ||
930 (tp->busy != 0))
931 break;
932 if ((tp->queue - tp->pc) == PQ_CACHE) {
933 vm_page_flag_clear(tp, PG_CLEANCHK);
934 break;
935 }
936 vm_page_test_dirty(tp);
937 if ((tp->dirty & tp->valid) == 0) {
938 vm_page_flag_clear(tp, PG_CLEANCHK);
939 break;
940 }
941 mab[ i - 1 ] = tp;
942 maxb++;
943 continue;
944 }
945 break;
946 }
947 }
948
949 for(i = 0; i < maxb; i++) {
950 int index = (maxb - i) - 1;
951 ma[index] = mab[i];
952 vm_page_flag_clear(ma[index], PG_CLEANCHK);
953 }
954 vm_page_flag_clear(p, PG_CLEANCHK);
955 ma[maxb] = p;
956 for(i = 0; i < maxf; i++) {
957 int index = (maxb + i) + 1;
958 ma[index] = maf[i];
959 vm_page_flag_clear(ma[index], PG_CLEANCHK);
960 }
961 runlen = maxb + maxf + 1;
962
963 vm_pageout_flush(ma, runlen, pagerflags);
964 for (i = 0; i < runlen; i++) {
965 if (ma[i]->valid & ma[i]->dirty) {
966 pmap_page_protect(ma[i], VM_PROT_READ);
967 vm_page_flag_set(ma[i], PG_CLEANCHK);
968
969 /*
970 * maxf will end up being the actual number of pages
971 * we wrote out contiguously, non-inclusive of the
972 * first page. We do not count look-behind pages.
973 */
974 if (i >= maxb + 1 && (maxf > i - maxb - 1))
975 maxf = i - maxb - 1;
976 }
977 }
978 return(maxf + 1);
979 }
980
981 /*
982 * Note that there is absolutely no sense in writing out
983 * anonymous objects, so we track down the vnode object
984 * to write out.
985 * We invalidate (remove) all pages from the address space
986 * for semantic correctness.
987 *
988 * Note: certain anonymous maps, such as MAP_NOSYNC maps,
989 * may start out with a NULL object.
990 */
991 void
992 vm_object_sync(vm_object_t object, vm_ooffset_t offset, vm_size_t size,
993 boolean_t syncio, boolean_t invalidate)
994 {
995 vm_object_t backing_object;
996 struct vnode *vp;
997 int flags;
998
999 if (object == NULL)
1000 return;
1001 VM_OBJECT_LOCK(object);
1002 while ((backing_object = object->backing_object) != NULL) {
1003 VM_OBJECT_LOCK(backing_object);
1004 offset += object->backing_object_offset;
1005 VM_OBJECT_UNLOCK(object);
1006 object = backing_object;
1007 if (object->size < OFF_TO_IDX(offset + size))
1008 size = IDX_TO_OFF(object->size) - offset;
1009 }
1010 /*
1011 * Flush pages if writing is allowed, invalidate them
1012 * if invalidation requested. Pages undergoing I/O
1013 * will be ignored by vm_object_page_remove().
1014 *
1015 * We cannot lock the vnode and then wait for paging
1016 * to complete without deadlocking against vm_fault.
1017 * Instead we simply call vm_object_page_remove() and
1018 * allow it to block internally on a page-by-page
1019 * basis when it encounters pages undergoing async
1020 * I/O.
1021 */
1022 if (object->type == OBJT_VNODE &&
1023 (object->flags & OBJ_MIGHTBEDIRTY) != 0) {
1024 vp = object->handle;
1025 VM_OBJECT_UNLOCK(object);
1026 mtx_lock(&Giant);
1027 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY, curthread);
1028 flags = (syncio || invalidate) ? OBJPC_SYNC : 0;
1029 flags |= invalidate ? OBJPC_INVAL : 0;
1030 VM_OBJECT_LOCK(object);
1031 vm_object_page_clean(object,
1032 OFF_TO_IDX(offset),
1033 OFF_TO_IDX(offset + size + PAGE_MASK),
1034 flags);
1035 VM_OBJECT_UNLOCK(object);
1036 VOP_UNLOCK(vp, 0, curthread);
1037 mtx_unlock(&Giant);
1038 VM_OBJECT_LOCK(object);
1039 }
1040 if ((object->type == OBJT_VNODE ||
1041 object->type == OBJT_DEVICE) && invalidate) {
1042 boolean_t purge;
1043 purge = old_msync || (object->type == OBJT_DEVICE);
1044 vm_object_page_remove(object,
1045 OFF_TO_IDX(offset),
1046 OFF_TO_IDX(offset + size + PAGE_MASK),
1047 purge ? FALSE : TRUE);
1048 }
1049 VM_OBJECT_UNLOCK(object);
1050 }
1051
1052 /*
1053 * vm_object_madvise:
1054 *
1055 * Implements the madvise function at the object/page level.
1056 *
1057 * MADV_WILLNEED (any object)
1058 *
1059 * Activate the specified pages if they are resident.
1060 *
1061 * MADV_DONTNEED (any object)
1062 *
1063 * Deactivate the specified pages if they are resident.
1064 *
1065 * MADV_FREE (OBJT_DEFAULT/OBJT_SWAP objects,
1066 * OBJ_ONEMAPPING only)
1067 *
1068 * Deactivate and clean the specified pages if they are
1069 * resident. This permits the process to reuse the pages
1070 * without faulting or the kernel to reclaim the pages
1071 * without I/O.
1072 */
1073 void
1074 vm_object_madvise(vm_object_t object, vm_pindex_t pindex, int count, int advise)
1075 {
1076 vm_pindex_t end, tpindex;
1077 vm_object_t backing_object, tobject;
1078 vm_page_t m;
1079
1080 if (object == NULL)
1081 return;
1082 VM_OBJECT_LOCK(object);
1083 end = pindex + count;
1084 /*
1085 * Locate and adjust resident pages
1086 */
1087 for (; pindex < end; pindex += 1) {
1088 relookup:
1089 tobject = object;
1090 tpindex = pindex;
1091 shadowlookup:
1092 /*
1093 * MADV_FREE only operates on OBJT_DEFAULT or OBJT_SWAP pages
1094 * and those pages must be OBJ_ONEMAPPING.
1095 */
1096 if (advise == MADV_FREE) {
1097 if ((tobject->type != OBJT_DEFAULT &&
1098 tobject->type != OBJT_SWAP) ||
1099 (tobject->flags & OBJ_ONEMAPPING) == 0) {
1100 goto unlock_tobject;
1101 }
1102 }
1103 m = vm_page_lookup(tobject, tpindex);
1104 if (m == NULL) {
1105 /*
1106 * There may be swap even if there is no backing page
1107 */
1108 if (advise == MADV_FREE && tobject->type == OBJT_SWAP)
1109 swap_pager_freespace(tobject, tpindex, 1);
1110 /*
1111 * next object
1112 */
1113 backing_object = tobject->backing_object;
1114 if (backing_object == NULL)
1115 goto unlock_tobject;
1116 VM_OBJECT_LOCK(backing_object);
1117 tpindex += OFF_TO_IDX(tobject->backing_object_offset);
1118 if (tobject != object)
1119 VM_OBJECT_UNLOCK(tobject);
1120 tobject = backing_object;
1121 goto shadowlookup;
1122 }
1123 /*
1124 * If the page is busy or not in a normal active state,
1125 * we skip it. If the page is not managed there are no
1126 * page queues to mess with. Things can break if we mess
1127 * with pages in any of the below states.
1128 */
1129 vm_page_lock_queues();
1130 if (m->hold_count ||
1131 m->wire_count ||
1132 (m->flags & PG_UNMANAGED) ||
1133 m->valid != VM_PAGE_BITS_ALL) {
1134 vm_page_unlock_queues();
1135 goto unlock_tobject;
1136 }
1137 if ((m->flags & PG_BUSY) || m->busy) {
1138 vm_page_flag_set(m, PG_WANTED | PG_REFERENCED);
1139 if (object != tobject)
1140 VM_OBJECT_UNLOCK(object);
1141 VM_OBJECT_UNLOCK(tobject);
1142 msleep(m, &vm_page_queue_mtx, PDROP | PVM, "madvpo", 0);
1143 VM_OBJECT_LOCK(object);
1144 goto relookup;
1145 }
1146 if (advise == MADV_WILLNEED) {
1147 vm_page_activate(m);
1148 } else if (advise == MADV_DONTNEED) {
1149 vm_page_dontneed(m);
1150 } else if (advise == MADV_FREE) {
1151 /*
1152 * Mark the page clean. This will allow the page
1153 * to be freed up by the system. However, such pages
1154 * are often reused quickly by malloc()/free()
1155 * so we do not do anything that would cause
1156 * a page fault if we can help it.
1157 *
1158 * Specifically, we do not try to actually free
1159 * the page now nor do we try to put it in the
1160 * cache (which would cause a page fault on reuse).
1161 *
1162 * But we do make the page is freeable as we
1163 * can without actually taking the step of unmapping
1164 * it.
1165 */
1166 pmap_clear_modify(m);
1167 m->dirty = 0;
1168 m->act_count = 0;
1169 vm_page_dontneed(m);
1170 }
1171 vm_page_unlock_queues();
1172 if (advise == MADV_FREE && tobject->type == OBJT_SWAP)
1173 swap_pager_freespace(tobject, tpindex, 1);
1174 unlock_tobject:
1175 if (tobject != object)
1176 VM_OBJECT_UNLOCK(tobject);
1177 }
1178 VM_OBJECT_UNLOCK(object);
1179 }
1180
1181 /*
1182 * vm_object_shadow:
1183 *
1184 * Create a new object which is backed by the
1185 * specified existing object range. The source
1186 * object reference is deallocated.
1187 *
1188 * The new object and offset into that object
1189 * are returned in the source parameters.
1190 */
1191 void
1192 vm_object_shadow(
1193 vm_object_t *object, /* IN/OUT */
1194 vm_ooffset_t *offset, /* IN/OUT */
1195 vm_size_t length)
1196 {
1197 vm_object_t source;
1198 vm_object_t result;
1199
1200 source = *object;
1201
1202 /*
1203 * Don't create the new object if the old object isn't shared.
1204 */
1205 if (source != NULL) {
1206 VM_OBJECT_LOCK(source);
1207 if (source->ref_count == 1 &&
1208 source->handle == NULL &&
1209 (source->type == OBJT_DEFAULT ||
1210 source->type == OBJT_SWAP)) {
1211 VM_OBJECT_UNLOCK(source);
1212 return;
1213 }
1214 VM_OBJECT_UNLOCK(source);
1215 }
1216
1217 /*
1218 * Allocate a new object with the given length.
1219 */
1220 result = vm_object_allocate(OBJT_DEFAULT, length);
1221
1222 /*
1223 * The new object shadows the source object, adding a reference to it.
1224 * Our caller changes his reference to point to the new object,
1225 * removing a reference to the source object. Net result: no change
1226 * of reference count.
1227 *
1228 * Try to optimize the result object's page color when shadowing
1229 * in order to maintain page coloring consistency in the combined
1230 * shadowed object.
1231 */
1232 result->backing_object = source;
1233 /*
1234 * Store the offset into the source object, and fix up the offset into
1235 * the new object.
1236 */
1237 result->backing_object_offset = *offset;
1238 if (source != NULL) {
1239 VM_OBJECT_LOCK(source);
1240 LIST_INSERT_HEAD(&source->shadow_head, result, shadow_list);
1241 source->shadow_count++;
1242 source->generation++;
1243 if (length < source->size)
1244 length = source->size;
1245 if (length > PQ_L2_SIZE / 3 + PQ_PRIME1 ||
1246 source->generation > 1)
1247 length = PQ_L2_SIZE / 3 + PQ_PRIME1;
1248 result->pg_color = (source->pg_color +
1249 length * source->generation) & PQ_L2_MASK;
1250 VM_OBJECT_UNLOCK(source);
1251 next_index = (result->pg_color + PQ_L2_SIZE / 3 + PQ_PRIME1) &
1252 PQ_L2_MASK;
1253 }
1254
1255
1256 /*
1257 * Return the new things
1258 */
1259 *offset = 0;
1260 *object = result;
1261 }
1262
1263 /*
1264 * vm_object_split:
1265 *
1266 * Split the pages in a map entry into a new object. This affords
1267 * easier removal of unused pages, and keeps object inheritance from
1268 * being a negative impact on memory usage.
1269 */
1270 void
1271 vm_object_split(vm_map_entry_t entry)
1272 {
1273 vm_page_t m;
1274 vm_object_t orig_object, new_object, source;
1275 vm_pindex_t offidxstart, offidxend;
1276 vm_size_t idx, size;
1277
1278 orig_object = entry->object.vm_object;
1279 if (orig_object->type != OBJT_DEFAULT && orig_object->type != OBJT_SWAP)
1280 return;
1281 if (orig_object->ref_count <= 1)
1282 return;
1283 VM_OBJECT_UNLOCK(orig_object);
1284
1285 offidxstart = OFF_TO_IDX(entry->offset);
1286 offidxend = offidxstart + OFF_TO_IDX(entry->end - entry->start);
1287 size = offidxend - offidxstart;
1288
1289 /*
1290 * If swap_pager_copy() is later called, it will convert new_object
1291 * into a swap object.
1292 */
1293 new_object = vm_object_allocate(OBJT_DEFAULT, size);
1294
1295 VM_OBJECT_LOCK(new_object);
1296 VM_OBJECT_LOCK(orig_object);
1297 source = orig_object->backing_object;
1298 if (source != NULL) {
1299 VM_OBJECT_LOCK(source);
1300 LIST_INSERT_HEAD(&source->shadow_head,
1301 new_object, shadow_list);
1302 source->shadow_count++;
1303 source->generation++;
1304 vm_object_reference_locked(source); /* for new_object */
1305 vm_object_clear_flag(source, OBJ_ONEMAPPING);
1306 VM_OBJECT_UNLOCK(source);
1307 new_object->backing_object_offset =
1308 orig_object->backing_object_offset + entry->offset;
1309 new_object->backing_object = source;
1310 }
1311 vm_page_lock_queues();
1312 for (idx = 0; idx < size; idx++) {
1313 retry:
1314 m = vm_page_lookup(orig_object, offidxstart + idx);
1315 if (m == NULL)
1316 continue;
1317
1318 /*
1319 * We must wait for pending I/O to complete before we can
1320 * rename the page.
1321 *
1322 * We do not have to VM_PROT_NONE the page as mappings should
1323 * not be changed by this operation.
1324 */
1325 if ((m->flags & PG_BUSY) || m->busy) {
1326 vm_page_flag_set(m, PG_WANTED | PG_REFERENCED);
1327 VM_OBJECT_UNLOCK(orig_object);
1328 VM_OBJECT_UNLOCK(new_object);
1329 msleep(m, &vm_page_queue_mtx, PDROP | PVM, "spltwt", 0);
1330 VM_OBJECT_LOCK(new_object);
1331 VM_OBJECT_LOCK(orig_object);
1332 vm_page_lock_queues();
1333 goto retry;
1334 }
1335 vm_page_rename(m, new_object, idx);
1336 /* page automatically made dirty by rename and cache handled */
1337 vm_page_busy(m);
1338 }
1339 vm_page_unlock_queues();
1340 if (orig_object->type == OBJT_SWAP) {
1341 /*
1342 * swap_pager_copy() can sleep, in which case the orig_object's
1343 * and new_object's locks are released and reacquired.
1344 */
1345 swap_pager_copy(orig_object, new_object, offidxstart, 0);
1346 }
1347 VM_OBJECT_UNLOCK(orig_object);
1348 vm_page_lock_queues();
1349 TAILQ_FOREACH(m, &new_object->memq, listq)
1350 vm_page_wakeup(m);
1351 vm_page_unlock_queues();
1352 VM_OBJECT_UNLOCK(new_object);
1353 entry->object.vm_object = new_object;
1354 entry->offset = 0LL;
1355 vm_object_deallocate(orig_object);
1356 VM_OBJECT_LOCK(new_object);
1357 }
1358
1359 #define OBSC_TEST_ALL_SHADOWED 0x0001
1360 #define OBSC_COLLAPSE_NOWAIT 0x0002
1361 #define OBSC_COLLAPSE_WAIT 0x0004
1362
1363 static int
1364 vm_object_backing_scan(vm_object_t object, int op)
1365 {
1366 int r = 1;
1367 vm_page_t p;
1368 vm_object_t backing_object;
1369 vm_pindex_t backing_offset_index;
1370
1371 VM_OBJECT_LOCK_ASSERT(object, MA_OWNED);
1372 VM_OBJECT_LOCK_ASSERT(object->backing_object, MA_OWNED);
1373
1374 backing_object = object->backing_object;
1375 backing_offset_index = OFF_TO_IDX(object->backing_object_offset);
1376
1377 /*
1378 * Initial conditions
1379 */
1380 if (op & OBSC_TEST_ALL_SHADOWED) {
1381 /*
1382 * We do not want to have to test for the existence of
1383 * swap pages in the backing object. XXX but with the
1384 * new swapper this would be pretty easy to do.
1385 *
1386 * XXX what about anonymous MAP_SHARED memory that hasn't
1387 * been ZFOD faulted yet? If we do not test for this, the
1388 * shadow test may succeed! XXX
1389 */
1390 if (backing_object->type != OBJT_DEFAULT) {
1391 return (0);
1392 }
1393 }
1394 if (op & OBSC_COLLAPSE_WAIT) {
1395 vm_object_set_flag(backing_object, OBJ_DEAD);
1396 }
1397
1398 /*
1399 * Our scan
1400 */
1401 p = TAILQ_FIRST(&backing_object->memq);
1402 while (p) {
1403 vm_page_t next = TAILQ_NEXT(p, listq);
1404 vm_pindex_t new_pindex = p->pindex - backing_offset_index;
1405
1406 if (op & OBSC_TEST_ALL_SHADOWED) {
1407 vm_page_t pp;
1408
1409 /*
1410 * Ignore pages outside the parent object's range
1411 * and outside the parent object's mapping of the
1412 * backing object.
1413 *
1414 * note that we do not busy the backing object's
1415 * page.
1416 */
1417 if (
1418 p->pindex < backing_offset_index ||
1419 new_pindex >= object->size
1420 ) {
1421 p = next;
1422 continue;
1423 }
1424
1425 /*
1426 * See if the parent has the page or if the parent's
1427 * object pager has the page. If the parent has the
1428 * page but the page is not valid, the parent's
1429 * object pager must have the page.
1430 *
1431 * If this fails, the parent does not completely shadow
1432 * the object and we might as well give up now.
1433 */
1434
1435 pp = vm_page_lookup(object, new_pindex);
1436 if (
1437 (pp == NULL || pp->valid == 0) &&
1438 !vm_pager_has_page(object, new_pindex, NULL, NULL)
1439 ) {
1440 r = 0;
1441 break;
1442 }
1443 }
1444
1445 /*
1446 * Check for busy page
1447 */
1448 if (op & (OBSC_COLLAPSE_WAIT | OBSC_COLLAPSE_NOWAIT)) {
1449 vm_page_t pp;
1450
1451 vm_page_lock_queues();
1452 if (op & OBSC_COLLAPSE_NOWAIT) {
1453 if ((p->flags & PG_BUSY) ||
1454 !p->valid ||
1455 p->hold_count ||
1456 p->wire_count ||
1457 p->busy) {
1458 vm_page_unlock_queues();
1459 p = next;
1460 continue;
1461 }
1462 } else if (op & OBSC_COLLAPSE_WAIT) {
1463 if ((p->flags & PG_BUSY) || p->busy) {
1464 vm_page_flag_set(p,
1465 PG_WANTED | PG_REFERENCED);
1466 VM_OBJECT_UNLOCK(backing_object);
1467 VM_OBJECT_UNLOCK(object);
1468 msleep(p, &vm_page_queue_mtx,
1469 PDROP | PVM, "vmocol", 0);
1470 VM_OBJECT_LOCK(object);
1471 VM_OBJECT_LOCK(backing_object);
1472 /*
1473 * If we slept, anything could have
1474 * happened. Since the object is
1475 * marked dead, the backing offset
1476 * should not have changed so we
1477 * just restart our scan.
1478 */
1479 p = TAILQ_FIRST(&backing_object->memq);
1480 continue;
1481 }
1482 }
1483
1484 /*
1485 * Busy the page
1486 */
1487 vm_page_busy(p);
1488 vm_page_unlock_queues();
1489
1490 KASSERT(
1491 p->object == backing_object,
1492 ("vm_object_backing_scan: object mismatch")
1493 );
1494
1495 /*
1496 * Destroy any associated swap
1497 */
1498 if (backing_object->type == OBJT_SWAP) {
1499 swap_pager_freespace(
1500 backing_object,
1501 p->pindex,
1502 1
1503 );
1504 }
1505
1506 if (
1507 p->pindex < backing_offset_index ||
1508 new_pindex >= object->size
1509 ) {
1510 /*
1511 * Page is out of the parent object's range, we
1512 * can simply destroy it.
1513 */
1514 vm_page_lock_queues();
1515 pmap_remove_all(p);
1516 vm_page_free(p);
1517 vm_page_unlock_queues();
1518 p = next;
1519 continue;
1520 }
1521
1522 pp = vm_page_lookup(object, new_pindex);
1523 if (
1524 pp != NULL ||
1525 vm_pager_has_page(object, new_pindex, NULL, NULL)
1526 ) {
1527 /*
1528 * page already exists in parent OR swap exists
1529 * for this location in the parent. Destroy
1530 * the original page from the backing object.
1531 *
1532 * Leave the parent's page alone
1533 */
1534 vm_page_lock_queues();
1535 pmap_remove_all(p);
1536 vm_page_free(p);
1537 vm_page_unlock_queues();
1538 p = next;
1539 continue;
1540 }
1541
1542 /*
1543 * Page does not exist in parent, rename the
1544 * page from the backing object to the main object.
1545 *
1546 * If the page was mapped to a process, it can remain
1547 * mapped through the rename.
1548 */
1549 vm_page_lock_queues();
1550 vm_page_rename(p, object, new_pindex);
1551 vm_page_unlock_queues();
1552 /* page automatically made dirty by rename */
1553 }
1554 p = next;
1555 }
1556 return (r);
1557 }
1558
1559
1560 /*
1561 * this version of collapse allows the operation to occur earlier and
1562 * when paging_in_progress is true for an object... This is not a complete
1563 * operation, but should plug 99.9% of the rest of the leaks.
1564 */
1565 static void
1566 vm_object_qcollapse(vm_object_t object)
1567 {
1568 vm_object_t backing_object = object->backing_object;
1569
1570 VM_OBJECT_LOCK_ASSERT(object, MA_OWNED);
1571 VM_OBJECT_LOCK_ASSERT(backing_object, MA_OWNED);
1572
1573 if (backing_object->ref_count != 1)
1574 return;
1575
1576 vm_object_backing_scan(object, OBSC_COLLAPSE_NOWAIT);
1577 }
1578
1579 /*
1580 * vm_object_collapse:
1581 *
1582 * Collapse an object with the object backing it.
1583 * Pages in the backing object are moved into the
1584 * parent, and the backing object is deallocated.
1585 */
1586 void
1587 vm_object_collapse(vm_object_t object)
1588 {
1589 VM_OBJECT_LOCK_ASSERT(object, MA_OWNED);
1590
1591 while (TRUE) {
1592 vm_object_t backing_object;
1593
1594 /*
1595 * Verify that the conditions are right for collapse:
1596 *
1597 * The object exists and the backing object exists.
1598 */
1599 if ((backing_object = object->backing_object) == NULL)
1600 break;
1601
1602 /*
1603 * we check the backing object first, because it is most likely
1604 * not collapsable.
1605 */
1606 VM_OBJECT_LOCK(backing_object);
1607 if (backing_object->handle != NULL ||
1608 (backing_object->type != OBJT_DEFAULT &&
1609 backing_object->type != OBJT_SWAP) ||
1610 (backing_object->flags & OBJ_DEAD) ||
1611 object->handle != NULL ||
1612 (object->type != OBJT_DEFAULT &&
1613 object->type != OBJT_SWAP) ||
1614 (object->flags & OBJ_DEAD)) {
1615 VM_OBJECT_UNLOCK(backing_object);
1616 break;
1617 }
1618
1619 if (
1620 object->paging_in_progress != 0 ||
1621 backing_object->paging_in_progress != 0
1622 ) {
1623 vm_object_qcollapse(object);
1624 VM_OBJECT_UNLOCK(backing_object);
1625 break;
1626 }
1627 /*
1628 * We know that we can either collapse the backing object (if
1629 * the parent is the only reference to it) or (perhaps) have
1630 * the parent bypass the object if the parent happens to shadow
1631 * all the resident pages in the entire backing object.
1632 *
1633 * This is ignoring pager-backed pages such as swap pages.
1634 * vm_object_backing_scan fails the shadowing test in this
1635 * case.
1636 */
1637 if (backing_object->ref_count == 1) {
1638 /*
1639 * If there is exactly one reference to the backing
1640 * object, we can collapse it into the parent.
1641 */
1642 vm_object_backing_scan(object, OBSC_COLLAPSE_WAIT);
1643
1644 /*
1645 * Move the pager from backing_object to object.
1646 */
1647 if (backing_object->type == OBJT_SWAP) {
1648 /*
1649 * swap_pager_copy() can sleep, in which case
1650 * the backing_object's and object's locks are
1651 * released and reacquired.
1652 */
1653 swap_pager_copy(
1654 backing_object,
1655 object,
1656 OFF_TO_IDX(object->backing_object_offset), TRUE);
1657 }
1658 /*
1659 * Object now shadows whatever backing_object did.
1660 * Note that the reference to
1661 * backing_object->backing_object moves from within
1662 * backing_object to within object.
1663 */
1664 LIST_REMOVE(object, shadow_list);
1665 backing_object->shadow_count--;
1666 backing_object->generation++;
1667 if (backing_object->backing_object) {
1668 VM_OBJECT_LOCK(backing_object->backing_object);
1669 LIST_REMOVE(backing_object, shadow_list);
1670 LIST_INSERT_HEAD(
1671 &backing_object->backing_object->shadow_head,
1672 object, shadow_list);
1673 /*
1674 * The shadow_count has not changed.
1675 */
1676 backing_object->backing_object->generation++;
1677 VM_OBJECT_UNLOCK(backing_object->backing_object);
1678 }
1679 object->backing_object = backing_object->backing_object;
1680 object->backing_object_offset +=
1681 backing_object->backing_object_offset;
1682
1683 /*
1684 * Discard backing_object.
1685 *
1686 * Since the backing object has no pages, no pager left,
1687 * and no object references within it, all that is
1688 * necessary is to dispose of it.
1689 */
1690 KASSERT(backing_object->ref_count == 1, ("backing_object %p was somehow re-referenced during collapse!", backing_object));
1691 VM_OBJECT_UNLOCK(backing_object);
1692
1693 mtx_lock(&vm_object_list_mtx);
1694 TAILQ_REMOVE(
1695 &vm_object_list,
1696 backing_object,
1697 object_list
1698 );
1699 mtx_unlock(&vm_object_list_mtx);
1700
1701 uma_zfree(obj_zone, backing_object);
1702
1703 object_collapses++;
1704 } else {
1705 vm_object_t new_backing_object;
1706
1707 /*
1708 * If we do not entirely shadow the backing object,
1709 * there is nothing we can do so we give up.
1710 */
1711 if (vm_object_backing_scan(object, OBSC_TEST_ALL_SHADOWED) == 0) {
1712 VM_OBJECT_UNLOCK(backing_object);
1713 break;
1714 }
1715
1716 /*
1717 * Make the parent shadow the next object in the
1718 * chain. Deallocating backing_object will not remove
1719 * it, since its reference count is at least 2.
1720 */
1721 LIST_REMOVE(object, shadow_list);
1722 backing_object->shadow_count--;
1723 backing_object->generation++;
1724
1725 new_backing_object = backing_object->backing_object;
1726 if ((object->backing_object = new_backing_object) != NULL) {
1727 VM_OBJECT_LOCK(new_backing_object);
1728 LIST_INSERT_HEAD(
1729 &new_backing_object->shadow_head,
1730 object,
1731 shadow_list
1732 );
1733 new_backing_object->shadow_count++;
1734 new_backing_object->generation++;
1735 vm_object_reference_locked(new_backing_object);
1736 VM_OBJECT_UNLOCK(new_backing_object);
1737 object->backing_object_offset +=
1738 backing_object->backing_object_offset;
1739 }
1740
1741 /*
1742 * Drop the reference count on backing_object. Since
1743 * its ref_count was at least 2, it will not vanish.
1744 */
1745 backing_object->ref_count--;
1746 VM_OBJECT_UNLOCK(backing_object);
1747 object_bypasses++;
1748 }
1749
1750 /*
1751 * Try again with this object's new backing object.
1752 */
1753 }
1754 }
1755
1756 /*
1757 * vm_object_page_remove:
1758 *
1759 * Removes all physical pages in the given range from the
1760 * object's list of pages. If the range's end is zero, all
1761 * physical pages from the range's start to the end of the object
1762 * are deleted.
1763 *
1764 * The object must be locked.
1765 */
1766 void
1767 vm_object_page_remove(vm_object_t object, vm_pindex_t start, vm_pindex_t end,
1768 boolean_t clean_only)
1769 {
1770 vm_page_t p, next;
1771
1772 VM_OBJECT_LOCK_ASSERT(object, MA_OWNED);
1773 if (object->resident_page_count == 0)
1774 return;
1775
1776 /*
1777 * Since physically-backed objects do not use managed pages, we can't
1778 * remove pages from the object (we must instead remove the page
1779 * references, and then destroy the object).
1780 */
1781 KASSERT(object->type != OBJT_PHYS,
1782 ("attempt to remove pages from a physical object"));
1783
1784 vm_object_pip_add(object, 1);
1785 again:
1786 vm_page_lock_queues();
1787 if ((p = TAILQ_FIRST(&object->memq)) != NULL) {
1788 if (p->pindex < start) {
1789 p = vm_page_splay(start, object->root);
1790 if ((object->root = p)->pindex < start)
1791 p = TAILQ_NEXT(p, listq);
1792 }
1793 }
1794 /*
1795 * Assert: the variable p is either (1) the page with the
1796 * least pindex greater than or equal to the parameter pindex
1797 * or (2) NULL.
1798 */
1799 for (;
1800 p != NULL && (p->pindex < end || end == 0);
1801 p = next) {
1802 next = TAILQ_NEXT(p, listq);
1803
1804 if (p->wire_count != 0) {
1805 pmap_remove_all(p);
1806 if (!clean_only)
1807 p->valid = 0;
1808 continue;
1809 }
1810 if (vm_page_sleep_if_busy(p, TRUE, "vmopar"))
1811 goto again;
1812 if (clean_only && p->valid) {
1813 pmap_page_protect(p, VM_PROT_READ | VM_PROT_EXECUTE);
1814 if (p->valid & p->dirty)
1815 continue;
1816 }
1817 pmap_remove_all(p);
1818 vm_page_free(p);
1819 }
1820 vm_page_unlock_queues();
1821 vm_object_pip_wakeup(object);
1822 }
1823
1824 /*
1825 * Routine: vm_object_coalesce
1826 * Function: Coalesces two objects backing up adjoining
1827 * regions of memory into a single object.
1828 *
1829 * returns TRUE if objects were combined.
1830 *
1831 * NOTE: Only works at the moment if the second object is NULL -
1832 * if it's not, which object do we lock first?
1833 *
1834 * Parameters:
1835 * prev_object First object to coalesce
1836 * prev_offset Offset into prev_object
1837 * prev_size Size of reference to prev_object
1838 * next_size Size of reference to the second object
1839 *
1840 * Conditions:
1841 * The object must *not* be locked.
1842 */
1843 boolean_t
1844 vm_object_coalesce(vm_object_t prev_object, vm_ooffset_t prev_offset,
1845 vm_size_t prev_size, vm_size_t next_size)
1846 {
1847 vm_pindex_t next_pindex;
1848
1849 if (prev_object == NULL)
1850 return (TRUE);
1851 VM_OBJECT_LOCK(prev_object);
1852 if (prev_object->type != OBJT_DEFAULT &&
1853 prev_object->type != OBJT_SWAP) {
1854 VM_OBJECT_UNLOCK(prev_object);
1855 return (FALSE);
1856 }
1857
1858 /*
1859 * Try to collapse the object first
1860 */
1861 vm_object_collapse(prev_object);
1862
1863 /*
1864 * Can't coalesce if: . more than one reference . paged out . shadows
1865 * another object . has a copy elsewhere (any of which mean that the
1866 * pages not mapped to prev_entry may be in use anyway)
1867 */
1868 if (prev_object->backing_object != NULL) {
1869 VM_OBJECT_UNLOCK(prev_object);
1870 return (FALSE);
1871 }
1872
1873 prev_size >>= PAGE_SHIFT;
1874 next_size >>= PAGE_SHIFT;
1875 next_pindex = OFF_TO_IDX(prev_offset) + prev_size;
1876
1877 if ((prev_object->ref_count > 1) &&
1878 (prev_object->size != next_pindex)) {
1879 VM_OBJECT_UNLOCK(prev_object);
1880 return (FALSE);
1881 }
1882
1883 /*
1884 * Remove any pages that may still be in the object from a previous
1885 * deallocation.
1886 */
1887 if (next_pindex < prev_object->size) {
1888 vm_object_page_remove(prev_object,
1889 next_pindex,
1890 next_pindex + next_size, FALSE);
1891 if (prev_object->type == OBJT_SWAP)
1892 swap_pager_freespace(prev_object,
1893 next_pindex, next_size);
1894 }
1895
1896 /*
1897 * Extend the object if necessary.
1898 */
1899 if (next_pindex + next_size > prev_object->size)
1900 prev_object->size = next_pindex + next_size;
1901
1902 VM_OBJECT_UNLOCK(prev_object);
1903 return (TRUE);
1904 }
1905
1906 void
1907 vm_object_set_writeable_dirty(vm_object_t object)
1908 {
1909 struct vnode *vp;
1910
1911 VM_OBJECT_LOCK_ASSERT(object, MA_OWNED);
1912 vm_object_set_flag(object, OBJ_WRITEABLE|OBJ_MIGHTBEDIRTY);
1913 if (object->type == OBJT_VNODE &&
1914 (vp = (struct vnode *)object->handle) != NULL) {
1915 VI_LOCK(vp);
1916 if ((vp->v_iflag & VI_OBJDIRTY) == 0)
1917 vp->v_iflag |= VI_OBJDIRTY;
1918 VI_UNLOCK(vp);
1919 }
1920 }
1921
1922 #include "opt_ddb.h"
1923 #ifdef DDB
1924 #include <sys/kernel.h>
1925
1926 #include <sys/cons.h>
1927
1928 #include <ddb/ddb.h>
1929
1930 static int
1931 _vm_object_in_map(vm_map_t map, vm_object_t object, vm_map_entry_t entry)
1932 {
1933 vm_map_t tmpm;
1934 vm_map_entry_t tmpe;
1935 vm_object_t obj;
1936 int entcount;
1937
1938 if (map == 0)
1939 return 0;
1940
1941 if (entry == 0) {
1942 tmpe = map->header.next;
1943 entcount = map->nentries;
1944 while (entcount-- && (tmpe != &map->header)) {
1945 if (_vm_object_in_map(map, object, tmpe)) {
1946 return 1;
1947 }
1948 tmpe = tmpe->next;
1949 }
1950 } else if (entry->eflags & MAP_ENTRY_IS_SUB_MAP) {
1951 tmpm = entry->object.sub_map;
1952 tmpe = tmpm->header.next;
1953 entcount = tmpm->nentries;
1954 while (entcount-- && tmpe != &tmpm->header) {
1955 if (_vm_object_in_map(tmpm, object, tmpe)) {
1956 return 1;
1957 }
1958 tmpe = tmpe->next;
1959 }
1960 } else if ((obj = entry->object.vm_object) != NULL) {
1961 for (; obj; obj = obj->backing_object)
1962 if (obj == object) {
1963 return 1;
1964 }
1965 }
1966 return 0;
1967 }
1968
1969 static int
1970 vm_object_in_map(vm_object_t object)
1971 {
1972 struct proc *p;
1973
1974 /* sx_slock(&allproc_lock); */
1975 LIST_FOREACH(p, &allproc, p_list) {
1976 if (!p->p_vmspace /* || (p->p_flag & (P_SYSTEM|P_WEXIT)) */)
1977 continue;
1978 if (_vm_object_in_map(&p->p_vmspace->vm_map, object, 0)) {
1979 /* sx_sunlock(&allproc_lock); */
1980 return 1;
1981 }
1982 }
1983 /* sx_sunlock(&allproc_lock); */
1984 if (_vm_object_in_map(kernel_map, object, 0))
1985 return 1;
1986 if (_vm_object_in_map(kmem_map, object, 0))
1987 return 1;
1988 if (_vm_object_in_map(pager_map, object, 0))
1989 return 1;
1990 if (_vm_object_in_map(buffer_map, object, 0))
1991 return 1;
1992 return 0;
1993 }
1994
1995 DB_SHOW_COMMAND(vmochk, vm_object_check)
1996 {
1997 vm_object_t object;
1998
1999 /*
2000 * make sure that internal objs are in a map somewhere
2001 * and none have zero ref counts.
2002 */
2003 TAILQ_FOREACH(object, &vm_object_list, object_list) {
2004 if (object->handle == NULL &&
2005 (object->type == OBJT_DEFAULT || object->type == OBJT_SWAP)) {
2006 if (object->ref_count == 0) {
2007 db_printf("vmochk: internal obj has zero ref count: %ld\n",
2008 (long)object->size);
2009 }
2010 if (!vm_object_in_map(object)) {
2011 db_printf(
2012 "vmochk: internal obj is not in a map: "
2013 "ref: %d, size: %lu: 0x%lx, backing_object: %p\n",
2014 object->ref_count, (u_long)object->size,
2015 (u_long)object->size,
2016 (void *)object->backing_object);
2017 }
2018 }
2019 }
2020 }
2021
2022 /*
2023 * vm_object_print: [ debug ]
2024 */
2025 DB_SHOW_COMMAND(object, vm_object_print_static)
2026 {
2027 /* XXX convert args. */
2028 vm_object_t object = (vm_object_t)addr;
2029 boolean_t full = have_addr;
2030
2031 vm_page_t p;
2032
2033 /* XXX count is an (unused) arg. Avoid shadowing it. */
2034 #define count was_count
2035
2036 int count;
2037
2038 if (object == NULL)
2039 return;
2040
2041 db_iprintf(
2042 "Object %p: type=%d, size=0x%jx, res=%d, ref=%d, flags=0x%x\n",
2043 object, (int)object->type, (uintmax_t)object->size,
2044 object->resident_page_count, object->ref_count, object->flags);
2045 db_iprintf(" sref=%d, backing_object(%d)=(%p)+0x%jx\n",
2046 object->shadow_count,
2047 object->backing_object ? object->backing_object->ref_count : 0,
2048 object->backing_object, (uintmax_t)object->backing_object_offset);
2049
2050 if (!full)
2051 return;
2052
2053 db_indent += 2;
2054 count = 0;
2055 TAILQ_FOREACH(p, &object->memq, listq) {
2056 if (count == 0)
2057 db_iprintf("memory:=");
2058 else if (count == 6) {
2059 db_printf("\n");
2060 db_iprintf(" ...");
2061 count = 0;
2062 } else
2063 db_printf(",");
2064 count++;
2065
2066 db_printf("(off=0x%jx,page=0x%jx)",
2067 (uintmax_t)p->pindex, (uintmax_t)VM_PAGE_TO_PHYS(p));
2068 }
2069 if (count != 0)
2070 db_printf("\n");
2071 db_indent -= 2;
2072 }
2073
2074 /* XXX. */
2075 #undef count
2076
2077 /* XXX need this non-static entry for calling from vm_map_print. */
2078 void
2079 vm_object_print(
2080 /* db_expr_t */ long addr,
2081 boolean_t have_addr,
2082 /* db_expr_t */ long count,
2083 char *modif)
2084 {
2085 vm_object_print_static(addr, have_addr, count, modif);
2086 }
2087
2088 DB_SHOW_COMMAND(vmopag, vm_object_print_pages)
2089 {
2090 vm_object_t object;
2091 int nl = 0;
2092 int c;
2093
2094 TAILQ_FOREACH(object, &vm_object_list, object_list) {
2095 vm_pindex_t idx, fidx;
2096 vm_pindex_t osize;
2097 vm_paddr_t pa = -1, padiff;
2098 int rcount;
2099 vm_page_t m;
2100
2101 db_printf("new object: %p\n", (void *)object);
2102 if (nl > 18) {
2103 c = cngetc();
2104 if (c != ' ')
2105 return;
2106 nl = 0;
2107 }
2108 nl++;
2109 rcount = 0;
2110 fidx = 0;
2111 osize = object->size;
2112 if (osize > 128)
2113 osize = 128;
2114 for (idx = 0; idx < osize; idx++) {
2115 m = vm_page_lookup(object, idx);
2116 if (m == NULL) {
2117 if (rcount) {
2118 db_printf(" index(%ld)run(%d)pa(0x%lx)\n",
2119 (long)fidx, rcount, (long)pa);
2120 if (nl > 18) {
2121 c = cngetc();
2122 if (c != ' ')
2123 return;
2124 nl = 0;
2125 }
2126 nl++;
2127 rcount = 0;
2128 }
2129 continue;
2130 }
2131
2132
2133 if (rcount &&
2134 (VM_PAGE_TO_PHYS(m) == pa + rcount * PAGE_SIZE)) {
2135 ++rcount;
2136 continue;
2137 }
2138 if (rcount) {
2139 padiff = pa + rcount * PAGE_SIZE - VM_PAGE_TO_PHYS(m);
2140 padiff >>= PAGE_SHIFT;
2141 padiff &= PQ_L2_MASK;
2142 if (padiff == 0) {
2143 pa = VM_PAGE_TO_PHYS(m) - rcount * PAGE_SIZE;
2144 ++rcount;
2145 continue;
2146 }
2147 db_printf(" index(%ld)run(%d)pa(0x%lx)",
2148 (long)fidx, rcount, (long)pa);
2149 db_printf("pd(%ld)\n", (long)padiff);
2150 if (nl > 18) {
2151 c = cngetc();
2152 if (c != ' ')
2153 return;
2154 nl = 0;
2155 }
2156 nl++;
2157 }
2158 fidx = idx;
2159 pa = VM_PAGE_TO_PHYS(m);
2160 rcount = 1;
2161 }
2162 if (rcount) {
2163 db_printf(" index(%ld)run(%d)pa(0x%lx)\n",
2164 (long)fidx, rcount, (long)pa);
2165 if (nl > 18) {
2166 c = cngetc();
2167 if (c != ' ')
2168 return;
2169 nl = 0;
2170 }
2171 nl++;
2172 }
2173 }
2174 }
2175 #endif /* DDB */
Cache object: 16d6f48f4049a85125645e4ead4c1923
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