kernel - SWAP CACHE part 11/many - Write improvements, fix backing store free
[dragonfly.git] / sys / vm / vm_object.c
CommitLineData
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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 * 3. All advertising materials mentioning features or use of this software
17 * must display the following acknowledgement:
18 * This product includes software developed by the University of
19 * California, Berkeley and its contributors.
20 * 4. Neither the name of the University nor the names of its contributors
21 * may be used to endorse or promote products derived from this software
22 * without specific prior written permission.
23 *
24 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
25 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
26 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
27 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
28 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
29 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
30 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
31 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
32 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
33 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
34 * SUCH DAMAGE.
35 *
36 * from: @(#)vm_object.c 8.5 (Berkeley) 3/22/94
37 *
38 *
39 * Copyright (c) 1987, 1990 Carnegie-Mellon University.
40 * All rights reserved.
41 *
42 * Authors: Avadis Tevanian, Jr., Michael Wayne Young
43 *
44 * Permission to use, copy, modify and distribute this software and
45 * its documentation is hereby granted, provided that both the copyright
46 * notice and this permission notice appear in all copies of the
47 * software, derivative works or modified versions, and any portions
48 * thereof, and that both notices appear in supporting documentation.
49 *
50 * CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS"
51 * CONDITION. CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND
52 * FOR ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
53 *
54 * Carnegie Mellon requests users of this software to return to
55 *
56 * Software Distribution Coordinator or Software.Distribution@CS.CMU.EDU
57 * School of Computer Science
58 * Carnegie Mellon University
59 * Pittsburgh PA 15213-3890
60 *
61 * any improvements or extensions that they make and grant Carnegie the
62 * rights to redistribute these changes.
63 *
64 * $FreeBSD: src/sys/vm/vm_object.c,v 1.171.2.8 2003/05/26 19:17:56 alc Exp $
17cde63e 65 * $DragonFly: src/sys/vm/vm_object.c,v 1.33 2008/05/09 07:24:48 dillon Exp $
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66 */
67
68/*
69 * Virtual memory object module.
70 */
71
72#include <sys/param.h>
73#include <sys/systm.h>
74#include <sys/proc.h> /* for curproc, pageproc */
75#include <sys/vnode.h>
76#include <sys/vmmeter.h>
77#include <sys/mman.h>
78#include <sys/mount.h>
79#include <sys/kernel.h>
80#include <sys/sysctl.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/vm_zone.h>
94
95#define EASY_SCAN_FACTOR 8
96
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97static void vm_object_qcollapse(vm_object_t object);
98static int vm_object_page_collect_flush(vm_object_t object, vm_page_t p,
99 int pagerflags);
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100
101/*
102 * Virtual memory objects maintain the actual data
103 * associated with allocated virtual memory. A given
104 * page of memory exists within exactly one object.
105 *
106 * An object is only deallocated when all "references"
107 * are given up. Only one "reference" to a given
108 * region of an object should be writeable.
109 *
110 * Associated with each object is a list of all resident
111 * memory pages belonging to that object; this list is
112 * maintained by the "vm_page" module, and locked by the object's
113 * lock.
114 *
115 * Each object also records a "pager" routine which is
116 * used to retrieve (and store) pages to the proper backing
117 * storage. In addition, objects may be backed by other
118 * objects from which they were virtual-copied.
119 *
120 * The only items within the object structure which are
121 * modified after time of creation are:
122 * reference count locked by object's lock
123 * pager routine locked by object's lock
124 *
125 */
126
127struct object_q vm_object_list;
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128struct vm_object kernel_object;
129
984263bc 130static long vm_object_count; /* count of all objects */
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131extern int vm_pageout_page_count;
132
133static long object_collapses;
134static long object_bypasses;
135static int next_index;
136static vm_zone_t obj_zone;
137static struct vm_zone obj_zone_store;
138static int object_hash_rand;
139#define VM_OBJECTS_INIT 256
140static struct vm_object vm_objects_init[VM_OBJECTS_INIT];
141
142void
57e43348 143_vm_object_allocate(objtype_t type, vm_size_t size, vm_object_t object)
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144{
145 int incr;
1f804340 146 RB_INIT(&object->rb_memq);
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147 LIST_INIT(&object->shadow_head);
148
149 object->type = type;
150 object->size = size;
151 object->ref_count = 1;
152 object->flags = 0;
153 if ((object->type == OBJT_DEFAULT) || (object->type == OBJT_SWAP))
154 vm_object_set_flag(object, OBJ_ONEMAPPING);
155 object->paging_in_progress = 0;
156 object->resident_page_count = 0;
157 object->shadow_count = 0;
158 object->pg_color = next_index;
159 if ( size > (PQ_L2_SIZE / 3 + PQ_PRIME1))
160 incr = PQ_L2_SIZE / 3 + PQ_PRIME1;
161 else
162 incr = size;
163 next_index = (next_index + incr) & PQ_L2_MASK;
164 object->handle = NULL;
165 object->backing_object = NULL;
166 object->backing_object_offset = (vm_ooffset_t) 0;
167 /*
168 * Try to generate a number that will spread objects out in the
169 * hash table. We 'wipe' new objects across the hash in 128 page
170 * increments plus 1 more to offset it a little more by the time
171 * it wraps around.
172 */
173 object->hash_rand = object_hash_rand - 129;
174
175 object->generation++;
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176 object->swblock_count = 0;
177 RB_INIT(&object->swblock_root);
984263bc 178
fad57d0e 179 crit_enter();
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180 TAILQ_INSERT_TAIL(&vm_object_list, object, object_list);
181 vm_object_count++;
182 object_hash_rand = object->hash_rand;
fad57d0e 183 crit_exit();
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184}
185
186/*
187 * vm_object_init:
188 *
189 * Initialize the VM objects module.
190 */
191void
57e43348 192vm_object_init(void)
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193{
194 TAILQ_INIT(&vm_object_list);
984263bc 195
e4846942 196 _vm_object_allocate(OBJT_DEFAULT, OFF_TO_IDX(KvaEnd),
c439ad8f 197 &kernel_object);
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198
199 obj_zone = &obj_zone_store;
200 zbootinit(obj_zone, "VM OBJECT", sizeof (struct vm_object),
201 vm_objects_init, VM_OBJECTS_INIT);
202}
203
204void
57e43348 205vm_object_init2(void)
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206{
207 zinitna(obj_zone, NULL, NULL, 0, 0, ZONE_PANICFAIL, 1);
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208}
209
210/*
211 * vm_object_allocate:
212 *
213 * Returns a new object with the given size.
214 */
215
216vm_object_t
57e43348 217vm_object_allocate(objtype_t type, vm_size_t size)
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218{
219 vm_object_t result;
220
221 result = (vm_object_t) zalloc(obj_zone);
222
223 _vm_object_allocate(type, size, result);
224
225 return (result);
226}
227
228
229/*
230 * vm_object_reference:
231 *
232 * Gets another reference to the given object.
233 */
234void
57e43348 235vm_object_reference(vm_object_t object)
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236{
237 if (object == NULL)
238 return;
239
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240 object->ref_count++;
241 if (object->type == OBJT_VNODE) {
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242 vref(object->handle);
243 /* XXX what if the vnode is being destroyed? */
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244 }
245}
246
b33a2ac2 247static void
57e43348 248vm_object_vndeallocate(vm_object_t object)
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249{
250 struct vnode *vp = (struct vnode *) object->handle;
251
252 KASSERT(object->type == OBJT_VNODE,
253 ("vm_object_vndeallocate: not a vnode object"));
254 KASSERT(vp != NULL, ("vm_object_vndeallocate: missing vp"));
255#ifdef INVARIANTS
256 if (object->ref_count == 0) {
257 vprint("vm_object_vndeallocate", vp);
258 panic("vm_object_vndeallocate: bad object reference count");
259 }
260#endif
261
262 object->ref_count--;
b33a2ac2 263 if (object->ref_count == 0)
2247fe02 264 vclrflags(vp, VTEXT);
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265 vrele(vp);
266}
267
268/*
269 * vm_object_deallocate:
270 *
271 * Release a reference to the specified object,
272 * gained either through a vm_object_allocate
273 * or a vm_object_reference call. When all references
274 * are gone, storage associated with this object
275 * may be relinquished.
276 *
277 * No object may be locked.
278 */
279void
57e43348 280vm_object_deallocate(vm_object_t object)
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281{
282 vm_object_t temp;
283
284 while (object != NULL) {
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285 if (object->type == OBJT_VNODE) {
286 vm_object_vndeallocate(object);
287 return;
288 }
289
290 if (object->ref_count == 0) {
291 panic("vm_object_deallocate: object deallocated too many times: %d", object->type);
292 } else if (object->ref_count > 2) {
293 object->ref_count--;
294 return;
295 }
296
297 /*
298 * Here on ref_count of one or two, which are special cases for
299 * objects.
300 */
301 if ((object->ref_count == 2) && (object->shadow_count == 0)) {
302 vm_object_set_flag(object, OBJ_ONEMAPPING);
303 object->ref_count--;
304 return;
305 } else if ((object->ref_count == 2) && (object->shadow_count == 1)) {
306 object->ref_count--;
307 if ((object->handle == NULL) &&
308 (object->type == OBJT_DEFAULT ||
309 object->type == OBJT_SWAP)) {
310 vm_object_t robject;
311
312 robject = LIST_FIRST(&object->shadow_head);
313 KASSERT(robject != NULL,
314 ("vm_object_deallocate: ref_count: %d, shadow_count: %d",
315 object->ref_count,
316 object->shadow_count));
317 if ((robject->handle == NULL) &&
318 (robject->type == OBJT_DEFAULT ||
319 robject->type == OBJT_SWAP)) {
320
321 robject->ref_count++;
322
323 while (
324 robject->paging_in_progress ||
325 object->paging_in_progress
326 ) {
327 vm_object_pip_sleep(robject, "objde1");
328 vm_object_pip_sleep(object, "objde2");
329 }
330
331 if (robject->ref_count == 1) {
332 robject->ref_count--;
333 object = robject;
334 goto doterm;
335 }
336
337 object = robject;
338 vm_object_collapse(object);
339 continue;
340 }
341 }
342
343 return;
344
345 } else {
346 object->ref_count--;
347 if (object->ref_count != 0)
348 return;
349 }
350
351doterm:
352
353 temp = object->backing_object;
354 if (temp) {
355 LIST_REMOVE(object, shadow_list);
356 temp->shadow_count--;
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357 temp->generation++;
358 object->backing_object = NULL;
359 }
360
361 /*
362 * Don't double-terminate, we could be in a termination
363 * recursion due to the terminate having to sync data
364 * to disk.
365 */
366 if ((object->flags & OBJ_DEAD) == 0)
367 vm_object_terminate(object);
368 object = temp;
369 }
370}
371
372/*
373 * vm_object_terminate actually destroys the specified object, freeing
374 * up all previously used resources.
375 *
376 * The object must be locked.
377 * This routine may block.
378 */
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379static int vm_object_terminate_callback(vm_page_t p, void *data);
380
984263bc 381void
57e43348 382vm_object_terminate(vm_object_t object)
984263bc 383{
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384 /*
385 * Make sure no one uses us.
386 */
387 vm_object_set_flag(object, OBJ_DEAD);
388
389 /*
390 * wait for the pageout daemon to be done with the object
391 */
392 vm_object_pip_wait(object, "objtrm");
393
394 KASSERT(!object->paging_in_progress,
395 ("vm_object_terminate: pageout in progress"));
396
397 /*
398 * Clean and free the pages, as appropriate. All references to the
399 * object are gone, so we don't need to lock it.
400 */
401 if (object->type == OBJT_VNODE) {
402 struct vnode *vp;
403
404 /*
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405 * Clean pages and flush buffers.
406 */
407 vm_object_page_clean(object, 0, 0, OBJPC_SYNC);
408
409 vp = (struct vnode *) object->handle;
87de5057 410 vinvalbuf(vp, V_SAVE, 0, 0);
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411 }
412
413 /*
414 * Wait for any I/O to complete, after which there had better not
415 * be any references left on the object.
416 */
417 vm_object_pip_wait(object, "objtrm");
418
419 if (object->ref_count != 0)
420 panic("vm_object_terminate: object with references, ref_count=%d", object->ref_count);
421
422 /*
423 * Now free any remaining pages. For internal objects, this also
424 * removes them from paging queues. Don't free wired pages, just
425 * remove them from the object.
426 */
5fd012e0 427 crit_enter();
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428 vm_page_rb_tree_RB_SCAN(&object->rb_memq, NULL,
429 vm_object_terminate_callback, NULL);
5fd012e0 430 crit_exit();
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431
432 /*
433 * Let the pager know object is dead.
434 */
435 vm_pager_deallocate(object);
436
437 /*
438 * Remove the object from the global object list.
439 */
fad57d0e 440 crit_enter();
984263bc 441 TAILQ_REMOVE(&vm_object_list, object, object_list);
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442 vm_object_count--;
443 crit_exit();
984263bc 444
9e12ff11 445 vm_object_dead_wakeup(object);
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446 if (object->ref_count != 0)
447 panic("vm_object_terminate2: object with references, ref_count=%d", object->ref_count);
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448
449 /*
450 * Free the space for the object.
451 */
452 zfree(obj_zone, object);
453}
454
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455static int
456vm_object_terminate_callback(vm_page_t p, void *data __unused)
457{
458 if (p->busy || (p->flags & PG_BUSY))
459 panic("vm_object_terminate: freeing busy page %p", p);
460 if (p->wire_count == 0) {
461 vm_page_busy(p);
462 vm_page_free(p);
463 mycpu->gd_cnt.v_pfree++;
464 } else {
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465 if (p->queue != PQ_NONE)
466 kprintf("vm_object_terminate: Warning: Encountered wired page %p on queue %d\n", p, p->queue);
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467 vm_page_busy(p);
468 vm_page_remove(p);
469 vm_page_wakeup(p);
470 }
471 return(0);
472}
473
984263bc 474/*
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475 * The object is dead but still has an object<->pager association. Sleep
476 * and return. The caller typically retests the association in a loop.
477 */
478void
479vm_object_dead_sleep(vm_object_t object, const char *wmesg)
480{
481 crit_enter();
482 if (object->handle) {
483 vm_object_set_flag(object, OBJ_DEADWNT);
484 tsleep(object, 0, wmesg, 0);
485 }
486 crit_exit();
487}
488
489/*
490 * Wakeup anyone waiting for the object<->pager disassociation on
491 * a dead object.
492 */
493void
494vm_object_dead_wakeup(vm_object_t object)
495{
496 if (object->flags & OBJ_DEADWNT) {
497 vm_object_clear_flag(object, OBJ_DEADWNT);
498 wakeup(object);
499 }
500}
501
502/*
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503 * vm_object_page_clean
504 *
505 * Clean all dirty pages in the specified range of object. Leaves page
506 * on whatever queue it is currently on. If NOSYNC is set then do not
507 * write out pages with PG_NOSYNC set (originally comes from MAP_NOSYNC),
508 * leaving the object dirty.
509 *
510 * When stuffing pages asynchronously, allow clustering. XXX we need a
511 * synchronous clustering mode implementation.
512 *
513 * Odd semantics: if start == end, we clean everything.
984263bc 514 */
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515static int vm_object_page_clean_pass1(struct vm_page *p, void *data);
516static int vm_object_page_clean_pass2(struct vm_page *p, void *data);
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517
518void
57e43348 519vm_object_page_clean(vm_object_t object, vm_pindex_t start, vm_pindex_t end,
1f804340 520 int flags)
984263bc 521{
1f804340 522 struct rb_vm_page_scan_info info;
984263bc 523 struct vnode *vp;
1f804340 524 int wholescan;
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525 int pagerflags;
526 int curgeneration;
527
528 if (object->type != OBJT_VNODE ||
529 (object->flags & OBJ_MIGHTBEDIRTY) == 0)
530 return;
531
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532 pagerflags = (flags & (OBJPC_SYNC | OBJPC_INVAL)) ?
533 VM_PAGER_PUT_SYNC : VM_PAGER_CLUSTER_OK;
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534 pagerflags |= (flags & OBJPC_INVAL) ? VM_PAGER_PUT_INVAL : 0;
535
536 vp = object->handle;
537
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538 /*
539 * Interlock other major object operations. This allows us to
540 * temporarily clear OBJ_WRITEABLE and OBJ_MIGHTBEDIRTY.
541 */
542 crit_enter();
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543 vm_object_set_flag(object, OBJ_CLEANING);
544
545 /*
546 * Handle 'entire object' case
547 */
1f804340 548 info.start_pindex = start;
984263bc 549 if (end == 0) {
1f804340 550 info.end_pindex = object->size - 1;
984263bc 551 } else {
1f804340 552 info.end_pindex = end - 1;
984263bc 553 }
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554 wholescan = (start == 0 && info.end_pindex == object->size - 1);
555 info.limit = flags;
556 info.pagerflags = pagerflags;
557 info.object = object;
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558
559 /*
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560 * If cleaning the entire object do a pass to mark the pages read-only.
561 * If everything worked out ok, clear OBJ_WRITEABLE and
562 * OBJ_MIGHTBEDIRTY.
984263bc 563 */
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564 if (wholescan) {
565 info.error = 0;
566 vm_page_rb_tree_RB_SCAN(&object->rb_memq, rb_vm_page_scancmp,
567 vm_object_page_clean_pass1, &info);
568 if (info.error == 0) {
569 vm_object_clear_flag(object,
570 OBJ_WRITEABLE|OBJ_MIGHTBEDIRTY);
571 if (object->type == OBJT_VNODE &&
572 (vp = (struct vnode *)object->handle) != NULL) {
573 if (vp->v_flag & VOBJDIRTY)
574 vclrflags(vp, VOBJDIRTY);
984263bc 575 }
984263bc 576 }
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577 }
578
579 /*
1f804340 580 * Do a pass to clean all the dirty pages we find.
984263bc 581 */
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582 do {
583 info.error = 0;
584 curgeneration = object->generation;
585 vm_page_rb_tree_RB_SCAN(&object->rb_memq, rb_vm_page_scancmp,
586 vm_object_page_clean_pass2, &info);
587 } while (info.error || curgeneration != object->generation);
984263bc 588
1f804340 589 vm_object_clear_flag(object, OBJ_CLEANING);
5fd012e0 590 crit_exit();
1f804340 591}
984263bc 592
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593static
594int
595vm_object_page_clean_pass1(struct vm_page *p, void *data)
596{
597 struct rb_vm_page_scan_info *info = data;
984263bc 598
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599 vm_page_flag_set(p, PG_CLEANCHK);
600 if ((info->limit & OBJPC_NOSYNC) && (p->flags & PG_NOSYNC))
601 info->error = 1;
602 else
17cde63e 603 vm_page_protect(p, VM_PROT_READ); /* must not block */
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604 return(0);
605}
606
607static
608int
609vm_object_page_clean_pass2(struct vm_page *p, void *data)
610{
611 struct rb_vm_page_scan_info *info = data;
612 int n;
984263bc 613
06ecca5a 614 /*
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615 * Do not mess with pages that were inserted after we started
616 * the cleaning pass.
06ecca5a 617 */
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618 if ((p->flags & PG_CLEANCHK) == 0)
619 return(0);
984263bc 620
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621 /*
622 * Before wasting time traversing the pmaps, check for trivial
623 * cases where the page cannot be dirty.
624 */
625 if (p->valid == 0 || (p->queue - p->pc) == PQ_CACHE) {
626 KKASSERT((p->dirty & p->valid) == 0);
627 return(0);
628 }
984263bc 629
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630 /*
631 * Check whether the page is dirty or not. The page has been set
632 * to be read-only so the check will not race a user dirtying the
633 * page.
634 */
635 vm_page_test_dirty(p);
636 if ((p->dirty & p->valid) == 0) {
637 vm_page_flag_clear(p, PG_CLEANCHK);
638 return(0);
639 }
984263bc 640
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641 /*
642 * If we have been asked to skip nosync pages and this is a
643 * nosync page, skip it. Note that the object flags were
644 * not cleared in this case (because pass1 will have returned an
645 * error), so we do not have to set them.
646 */
647 if ((info->limit & OBJPC_NOSYNC) && (p->flags & PG_NOSYNC)) {
648 vm_page_flag_clear(p, PG_CLEANCHK);
649 return(0);
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650 }
651
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652 /*
653 * Flush as many pages as we can. PG_CLEANCHK will be cleared on
654 * the pages that get successfully flushed. Set info->error if
655 * we raced an object modification.
656 */
657 n = vm_object_page_collect_flush(info->object, p, info->pagerflags);
658 if (n == 0)
659 info->error = 1;
660 return(0);
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661}
662
06ecca5a 663/*
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664 * This routine must be called within a critical section to properly avoid
665 * an interrupt unbusy/free race that can occur prior to the busy check.
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666 *
667 * Using the object generation number here to detect page ripout is not
668 * the best idea in the world. XXX
669 *
670 * NOTE: we operate under the assumption that a page found to not be busy
671 * will not be ripped out from under us by an interrupt. XXX we should
672 * recode this to explicitly busy the pages.
673 */
984263bc 674static int
1f804340 675vm_object_page_collect_flush(vm_object_t object, vm_page_t p, int pagerflags)
984263bc
MD
676{
677 int runlen;
984263bc
MD
678 int maxf;
679 int chkb;
680 int maxb;
681 int i;
1f804340 682 int curgeneration;
984263bc
MD
683 vm_pindex_t pi;
684 vm_page_t maf[vm_pageout_page_count];
685 vm_page_t mab[vm_pageout_page_count];
686 vm_page_t ma[vm_pageout_page_count];
687
1f804340
MD
688 curgeneration = object->generation;
689
984263bc
MD
690 pi = p->pindex;
691 while (vm_page_sleep_busy(p, TRUE, "vpcwai")) {
692 if (object->generation != curgeneration) {
984263bc
MD
693 return(0);
694 }
695 }
1f804340 696 KKASSERT(p->object == object && p->pindex == pi);
984263bc
MD
697
698 maxf = 0;
699 for(i = 1; i < vm_pageout_page_count; i++) {
700 vm_page_t tp;
701
702 if ((tp = vm_page_lookup(object, pi + i)) != NULL) {
703 if ((tp->flags & PG_BUSY) ||
704 ((pagerflags & VM_PAGER_IGNORE_CLEANCHK) == 0 &&
705 (tp->flags & PG_CLEANCHK) == 0) ||
706 (tp->busy != 0))
707 break;
708 if((tp->queue - tp->pc) == PQ_CACHE) {
709 vm_page_flag_clear(tp, PG_CLEANCHK);
710 break;
711 }
712 vm_page_test_dirty(tp);
713 if ((tp->dirty & tp->valid) == 0) {
714 vm_page_flag_clear(tp, PG_CLEANCHK);
715 break;
716 }
717 maf[ i - 1 ] = tp;
718 maxf++;
719 continue;
720 }
721 break;
722 }
723
724 maxb = 0;
725 chkb = vm_pageout_page_count - maxf;
726 if (chkb) {
727 for(i = 1; i < chkb;i++) {
728 vm_page_t tp;
729
730 if ((tp = vm_page_lookup(object, pi - i)) != NULL) {
731 if ((tp->flags & PG_BUSY) ||
732 ((pagerflags & VM_PAGER_IGNORE_CLEANCHK) == 0 &&
733 (tp->flags & PG_CLEANCHK) == 0) ||
734 (tp->busy != 0))
735 break;
736 if((tp->queue - tp->pc) == PQ_CACHE) {
737 vm_page_flag_clear(tp, PG_CLEANCHK);
738 break;
739 }
740 vm_page_test_dirty(tp);
741 if ((tp->dirty & tp->valid) == 0) {
742 vm_page_flag_clear(tp, PG_CLEANCHK);
743 break;
744 }
745 mab[ i - 1 ] = tp;
746 maxb++;
747 continue;
748 }
749 break;
750 }
751 }
752
753 for(i = 0; i < maxb; i++) {
754 int index = (maxb - i) - 1;
755 ma[index] = mab[i];
756 vm_page_flag_clear(ma[index], PG_CLEANCHK);
757 }
758 vm_page_flag_clear(p, PG_CLEANCHK);
759 ma[maxb] = p;
760 for(i = 0; i < maxf; i++) {
761 int index = (maxb + i) + 1;
762 ma[index] = maf[i];
763 vm_page_flag_clear(ma[index], PG_CLEANCHK);
764 }
765 runlen = maxb + maxf + 1;
766
984263bc
MD
767 vm_pageout_flush(ma, runlen, pagerflags);
768 for (i = 0; i < runlen; i++) {
769 if (ma[i]->valid & ma[i]->dirty) {
770 vm_page_protect(ma[i], VM_PROT_READ);
771 vm_page_flag_set(ma[i], PG_CLEANCHK);
772
773 /*
774 * maxf will end up being the actual number of pages
775 * we wrote out contiguously, non-inclusive of the
776 * first page. We do not count look-behind pages.
777 */
778 if (i >= maxb + 1 && (maxf > i - maxb - 1))
779 maxf = i - maxb - 1;
780 }
781 }
782 return(maxf + 1);
783}
784
785#ifdef not_used
786/* XXX I cannot tell if this should be an exported symbol */
787/*
788 * vm_object_deactivate_pages
789 *
790 * Deactivate all pages in the specified object. (Keep its pages
791 * in memory even though it is no longer referenced.)
792 *
793 * The object must be locked.
794 */
1f804340
MD
795static int vm_object_deactivate_pages_callback(vm_page_t p, void *data);
796
984263bc 797static void
57e43348 798vm_object_deactivate_pages(vm_object_t object)
984263bc 799{
5fd012e0 800 crit_enter();
1f804340
MD
801 vm_page_rb_tree_RB_SCAN(&object->rb_memq, NULL,
802 vm_object_deactivate_pages_callback, NULL);
5fd012e0 803 crit_exit();
984263bc 804}
1f804340
MD
805
806static int
807vm_object_deactivate_pages_callback(vm_page_t p, void *data __unused)
808{
809 vm_page_deactivate(p);
810 return(0);
811}
812
984263bc
MD
813#endif
814
815/*
816 * Same as vm_object_pmap_copy, except range checking really
817 * works, and is meant for small sections of an object.
818 *
819 * This code protects resident pages by making them read-only
820 * and is typically called on a fork or split when a page
821 * is converted to copy-on-write.
822 *
823 * NOTE: If the page is already at VM_PROT_NONE, calling
824 * vm_page_protect will have no effect.
825 */
984263bc 826void
57e43348 827vm_object_pmap_copy_1(vm_object_t object, vm_pindex_t start, vm_pindex_t end)
984263bc
MD
828{
829 vm_pindex_t idx;
830 vm_page_t p;
831
832 if (object == NULL || (object->flags & OBJ_WRITEABLE) == 0)
833 return;
834
06ecca5a
MD
835 /*
836 * spl protection needed to prevent races between the lookup,
837 * an interrupt unbusy/free, and our protect call.
838 */
5fd012e0 839 crit_enter();
984263bc
MD
840 for (idx = start; idx < end; idx++) {
841 p = vm_page_lookup(object, idx);
842 if (p == NULL)
843 continue;
844 vm_page_protect(p, VM_PROT_READ);
845 }
5fd012e0 846 crit_exit();
984263bc
MD
847}
848
849/*
850 * vm_object_pmap_remove:
851 *
852 * Removes all physical pages in the specified
853 * object range from all physical maps.
854 *
855 * The object must *not* be locked.
856 */
1f804340
MD
857
858static int vm_object_pmap_remove_callback(vm_page_t p, void *data);
859
984263bc 860void
57e43348 861vm_object_pmap_remove(vm_object_t object, vm_pindex_t start, vm_pindex_t end)
984263bc 862{
1f804340 863 struct rb_vm_page_scan_info info;
984263bc
MD
864
865 if (object == NULL)
866 return;
1f804340
MD
867 info.start_pindex = start;
868 info.end_pindex = end - 1;
5fd012e0 869 crit_enter();
1f804340
MD
870 vm_page_rb_tree_RB_SCAN(&object->rb_memq, rb_vm_page_scancmp,
871 vm_object_pmap_remove_callback, &info);
872 if (start == 0 && end == object->size)
984263bc 873 vm_object_clear_flag(object, OBJ_WRITEABLE);
1f804340
MD
874 crit_exit();
875}
876
877static int
878vm_object_pmap_remove_callback(vm_page_t p, void *data __unused)
879{
880 vm_page_protect(p, VM_PROT_NONE);
881 return(0);
984263bc
MD
882}
883
884/*
885 * vm_object_madvise:
886 *
887 * Implements the madvise function at the object/page level.
888 *
889 * MADV_WILLNEED (any object)
890 *
891 * Activate the specified pages if they are resident.
892 *
893 * MADV_DONTNEED (any object)
894 *
895 * Deactivate the specified pages if they are resident.
896 *
897 * MADV_FREE (OBJT_DEFAULT/OBJT_SWAP objects,
898 * OBJ_ONEMAPPING only)
899 *
900 * Deactivate and clean the specified pages if they are
901 * resident. This permits the process to reuse the pages
902 * without faulting or the kernel to reclaim the pages
903 * without I/O.
904 */
905void
57e43348 906vm_object_madvise(vm_object_t object, vm_pindex_t pindex, int count, int advise)
984263bc
MD
907{
908 vm_pindex_t end, tpindex;
909 vm_object_t tobject;
910 vm_page_t m;
911
912 if (object == NULL)
913 return;
914
915 end = pindex + count;
916
917 /*
918 * Locate and adjust resident pages
919 */
920
921 for (; pindex < end; pindex += 1) {
922relookup:
923 tobject = object;
924 tpindex = pindex;
925shadowlookup:
926 /*
927 * MADV_FREE only operates on OBJT_DEFAULT or OBJT_SWAP pages
928 * and those pages must be OBJ_ONEMAPPING.
929 */
930 if (advise == MADV_FREE) {
931 if ((tobject->type != OBJT_DEFAULT &&
932 tobject->type != OBJT_SWAP) ||
933 (tobject->flags & OBJ_ONEMAPPING) == 0) {
934 continue;
935 }
936 }
937
06ecca5a
MD
938 /*
939 * spl protection is required to avoid a race between the
940 * lookup, an interrupt unbusy/free, and our busy check.
941 */
942
5fd012e0 943 crit_enter();
984263bc
MD
944 m = vm_page_lookup(tobject, tpindex);
945
946 if (m == NULL) {
947 /*
948 * There may be swap even if there is no backing page
949 */
950 if (advise == MADV_FREE && tobject->type == OBJT_SWAP)
951 swap_pager_freespace(tobject, tpindex, 1);
952
953 /*
954 * next object
955 */
5fd012e0 956 crit_exit();
7cad6903 957 if (tobject->backing_object == NULL)
984263bc
MD
958 continue;
959 tpindex += OFF_TO_IDX(tobject->backing_object_offset);
7cad6903 960 tobject = tobject->backing_object;
984263bc
MD
961 goto shadowlookup;
962 }
963
964 /*
965 * If the page is busy or not in a normal active state,
966 * we skip it. If the page is not managed there are no
967 * page queues to mess with. Things can break if we mess
968 * with pages in any of the below states.
969 */
970 if (
971 m->hold_count ||
972 m->wire_count ||
973 (m->flags & PG_UNMANAGED) ||
974 m->valid != VM_PAGE_BITS_ALL
975 ) {
5fd012e0 976 crit_exit();
984263bc
MD
977 continue;
978 }
979
06ecca5a 980 if (vm_page_sleep_busy(m, TRUE, "madvpo")) {
5fd012e0 981 crit_exit();
984263bc 982 goto relookup;
06ecca5a 983 }
5fd012e0 984 crit_exit();
06ecca5a
MD
985
986 /*
987 * Theoretically once a page is known not to be busy, an
988 * interrupt cannot come along and rip it out from under us.
989 */
984263bc
MD
990
991 if (advise == MADV_WILLNEED) {
992 vm_page_activate(m);
993 } else if (advise == MADV_DONTNEED) {
994 vm_page_dontneed(m);
995 } else if (advise == MADV_FREE) {
996 /*
997 * Mark the page clean. This will allow the page
998 * to be freed up by the system. However, such pages
999 * are often reused quickly by malloc()/free()
1000 * so we do not do anything that would cause
1001 * a page fault if we can help it.
1002 *
1003 * Specifically, we do not try to actually free
1004 * the page now nor do we try to put it in the
1005 * cache (which would cause a page fault on reuse).
1006 *
1007 * But we do make the page is freeable as we
1008 * can without actually taking the step of unmapping
1009 * it.
1010 */
1011 pmap_clear_modify(m);
1012 m->dirty = 0;
1013 m->act_count = 0;
1014 vm_page_dontneed(m);
1015 if (tobject->type == OBJT_SWAP)
1016 swap_pager_freespace(tobject, tpindex, 1);
1017 }
1018 }
1019}
1020
1021/*
1022 * vm_object_shadow:
1023 *
1024 * Create a new object which is backed by the
1025 * specified existing object range. The source
1026 * object reference is deallocated.
1027 *
1028 * The new object and offset into that object
1029 * are returned in the source parameters.
1030 */
1031
1032void
57e43348
MD
1033vm_object_shadow(vm_object_t *object, /* IN/OUT */
1034 vm_ooffset_t *offset, /* IN/OUT */
1035 vm_size_t length)
984263bc
MD
1036{
1037 vm_object_t source;
1038 vm_object_t result;
1039
1040 source = *object;
1041
1042 /*
1043 * Don't create the new object if the old object isn't shared.
1044 */
1045
1046 if (source != NULL &&
1047 source->ref_count == 1 &&
1048 source->handle == NULL &&
1049 (source->type == OBJT_DEFAULT ||
1050 source->type == OBJT_SWAP))
1051 return;
1052
1053 /*
1054 * Allocate a new object with the given length
1055 */
1056
1057 if ((result = vm_object_allocate(OBJT_DEFAULT, length)) == NULL)
1058 panic("vm_object_shadow: no object for shadowing");
1059
1060 /*
1061 * The new object shadows the source object, adding a reference to it.
1062 * Our caller changes his reference to point to the new object,
1063 * removing a reference to the source object. Net result: no change
1064 * of reference count.
1065 *
1066 * Try to optimize the result object's page color when shadowing
1067 * in order to maintain page coloring consistency in the combined
1068 * shadowed object.
1069 */
1070 result->backing_object = source;
1071 if (source) {
1072 LIST_INSERT_HEAD(&source->shadow_head, result, shadow_list);
1073 source->shadow_count++;
1074 source->generation++;
1075 result->pg_color = (source->pg_color + OFF_TO_IDX(*offset)) & PQ_L2_MASK;
1076 }
1077
1078 /*
1079 * Store the offset into the source object, and fix up the offset into
1080 * the new object.
1081 */
1082
1083 result->backing_object_offset = *offset;
1084
1085 /*
1086 * Return the new things
1087 */
1088
1089 *offset = 0;
1090 *object = result;
1091}
1092
1093#define OBSC_TEST_ALL_SHADOWED 0x0001
1094#define OBSC_COLLAPSE_NOWAIT 0x0002
1095#define OBSC_COLLAPSE_WAIT 0x0004
1096
1f804340
MD
1097static int vm_object_backing_scan_callback(vm_page_t p, void *data);
1098
984263bc
MD
1099static __inline int
1100vm_object_backing_scan(vm_object_t object, int op)
1101{
1f804340 1102 struct rb_vm_page_scan_info info;
984263bc 1103 vm_object_t backing_object;
984263bc 1104
06ecca5a
MD
1105 /*
1106 * spl protection is required to avoid races between the memq/lookup,
1107 * an interrupt doing an unbusy/free, and our busy check. Amoung
1108 * other things.
1109 */
5fd012e0 1110 crit_enter();
984263bc
MD
1111
1112 backing_object = object->backing_object;
1f804340 1113 info.backing_offset_index = OFF_TO_IDX(object->backing_object_offset);
984263bc
MD
1114
1115 /*
1116 * Initial conditions
1117 */
1118
1119 if (op & OBSC_TEST_ALL_SHADOWED) {
1120 /*
1121 * We do not want to have to test for the existence of
1122 * swap pages in the backing object. XXX but with the
1123 * new swapper this would be pretty easy to do.
1124 *
1125 * XXX what about anonymous MAP_SHARED memory that hasn't
1126 * been ZFOD faulted yet? If we do not test for this, the
1127 * shadow test may succeed! XXX
1128 */
1129 if (backing_object->type != OBJT_DEFAULT) {
5fd012e0 1130 crit_exit();
984263bc
MD
1131 return(0);
1132 }
1133 }
1134 if (op & OBSC_COLLAPSE_WAIT) {
fad57d0e 1135 KKASSERT((backing_object->flags & OBJ_DEAD) == 0);
984263bc
MD
1136 vm_object_set_flag(backing_object, OBJ_DEAD);
1137 }
1138
1139 /*
1f804340
MD
1140 * Our scan. We have to retry if a negative error code is returned,
1141 * otherwise 0 or 1 will be returned in info.error. 0 Indicates that
1142 * the scan had to be stopped because the parent does not completely
1143 * shadow the child.
984263bc 1144 */
1f804340
MD
1145 info.object = object;
1146 info.backing_object = backing_object;
1147 info.limit = op;
1148 do {
1149 info.error = 1;
1150 vm_page_rb_tree_RB_SCAN(&backing_object->rb_memq, NULL,
1151 vm_object_backing_scan_callback,
1152 &info);
1153 } while (info.error < 0);
1154 crit_exit();
1155 return(info.error);
1156}
984263bc 1157
1f804340
MD
1158static int
1159vm_object_backing_scan_callback(vm_page_t p, void *data)
1160{
1161 struct rb_vm_page_scan_info *info = data;
1162 vm_object_t backing_object;
1163 vm_object_t object;
1164 vm_pindex_t new_pindex;
1165 vm_pindex_t backing_offset_index;
1166 int op;
984263bc 1167
1f804340
MD
1168 new_pindex = p->pindex - info->backing_offset_index;
1169 op = info->limit;
1170 object = info->object;
1171 backing_object = info->backing_object;
1172 backing_offset_index = info->backing_offset_index;
984263bc 1173
1f804340
MD
1174 if (op & OBSC_TEST_ALL_SHADOWED) {
1175 vm_page_t pp;
984263bc 1176
1f804340
MD
1177 /*
1178 * Ignore pages outside the parent object's range
1179 * and outside the parent object's mapping of the
1180 * backing object.
1181 *
1182 * note that we do not busy the backing object's
1183 * page.
1184 */
1185 if (
1186 p->pindex < backing_offset_index ||
1187 new_pindex >= object->size
1188 ) {
1189 return(0);
984263bc
MD
1190 }
1191
1192 /*
1f804340
MD
1193 * See if the parent has the page or if the parent's
1194 * object pager has the page. If the parent has the
1195 * page but the page is not valid, the parent's
1196 * object pager must have the page.
1197 *
1198 * If this fails, the parent does not completely shadow
1199 * the object and we might as well give up now.
984263bc
MD
1200 */
1201
1f804340 1202 pp = vm_page_lookup(object, new_pindex);
1b9d3514
MD
1203 if ((pp == NULL || pp->valid == 0) &&
1204 !vm_pager_has_page(object, new_pindex)
1f804340
MD
1205 ) {
1206 info->error = 0; /* problemo */
1207 return(-1); /* stop the scan */
1208 }
1209 }
984263bc 1210
1f804340
MD
1211 /*
1212 * Check for busy page
1213 */
984263bc 1214
1f804340
MD
1215 if (op & (OBSC_COLLAPSE_WAIT | OBSC_COLLAPSE_NOWAIT)) {
1216 vm_page_t pp;
984263bc 1217
1f804340 1218 if (op & OBSC_COLLAPSE_NOWAIT) {
984263bc 1219 if (
1f804340
MD
1220 (p->flags & PG_BUSY) ||
1221 !p->valid ||
1222 p->hold_count ||
1223 p->wire_count ||
1224 p->busy
984263bc 1225 ) {
1f804340 1226 return(0);
984263bc 1227 }
1f804340
MD
1228 } else if (op & OBSC_COLLAPSE_WAIT) {
1229 if (vm_page_sleep_busy(p, TRUE, "vmocol")) {
984263bc 1230 /*
1f804340
MD
1231 * If we slept, anything could have
1232 * happened. Ask that the scan be restarted.
984263bc 1233 *
1f804340
MD
1234 * Since the object is marked dead, the
1235 * backing offset should not have changed.
984263bc 1236 */
1f804340
MD
1237 info->error = -1;
1238 return(-1);
984263bc 1239 }
1f804340
MD
1240 }
1241
1242 /*
1243 * Busy the page
1244 */
1245 vm_page_busy(p);
984263bc 1246
1f804340
MD
1247 KASSERT(
1248 p->object == backing_object,
1249 ("vm_object_qcollapse(): object mismatch")
1250 );
1251
1252 /*
1253 * Destroy any associated swap
1254 */
8d292090
MD
1255 if (backing_object->type == OBJT_SWAP)
1256 swap_pager_freespace(backing_object, p->pindex, 1);
1f804340
MD
1257
1258 if (
1259 p->pindex < backing_offset_index ||
1260 new_pindex >= object->size
1261 ) {
984263bc 1262 /*
1f804340
MD
1263 * Page is out of the parent object's range, we
1264 * can simply destroy it.
984263bc 1265 */
1f804340
MD
1266 vm_page_protect(p, VM_PROT_NONE);
1267 vm_page_free(p);
1268 return(0);
1269 }
984263bc 1270
1f804340 1271 pp = vm_page_lookup(object, new_pindex);
1b9d3514 1272 if (pp != NULL || vm_pager_has_page(object, new_pindex)) {
1f804340
MD
1273 /*
1274 * page already exists in parent OR swap exists
1275 * for this location in the parent. Destroy
1276 * the original page from the backing object.
1277 *
1278 * Leave the parent's page alone
1279 */
1280 vm_page_protect(p, VM_PROT_NONE);
1281 vm_page_free(p);
1282 return(0);
984263bc 1283 }
1f804340
MD
1284
1285 /*
1286 * Page does not exist in parent, rename the
1287 * page from the backing object to the main object.
1288 *
1289 * If the page was mapped to a process, it can remain
1290 * mapped through the rename.
1291 */
1292 if ((p->queue - p->pc) == PQ_CACHE)
1293 vm_page_deactivate(p);
1294
1295 vm_page_rename(p, object, new_pindex);
1296 /* page automatically made dirty by rename */
984263bc 1297 }
1f804340 1298 return(0);
984263bc
MD
1299}
1300
984263bc
MD
1301/*
1302 * this version of collapse allows the operation to occur earlier and
1303 * when paging_in_progress is true for an object... This is not a complete
1304 * operation, but should plug 99.9% of the rest of the leaks.
1305 */
1306static void
57e43348 1307vm_object_qcollapse(vm_object_t object)
984263bc
MD
1308{
1309 vm_object_t backing_object = object->backing_object;
1310
1311 if (backing_object->ref_count != 1)
1312 return;
1313
1314 backing_object->ref_count += 2;
1315
1316 vm_object_backing_scan(object, OBSC_COLLAPSE_NOWAIT);
1317
1318 backing_object->ref_count -= 2;
1319}
1320
1321/*
1322 * vm_object_collapse:
1323 *
1324 * Collapse an object with the object backing it.
1325 * Pages in the backing object are moved into the
1326 * parent, and the backing object is deallocated.
1327 */
1328void
57e43348 1329vm_object_collapse(vm_object_t object)
984263bc
MD
1330{
1331 while (TRUE) {
1332 vm_object_t backing_object;
1333
1334 /*
1335 * Verify that the conditions are right for collapse:
1336 *
1337 * The object exists and the backing object exists.
1338 */
1339 if (object == NULL)
1340 break;
1341
1342 if ((backing_object = object->backing_object) == NULL)
1343 break;
1344
1345 /*
1346 * we check the backing object first, because it is most likely
1347 * not collapsable.
1348 */
1349 if (backing_object->handle != NULL ||
1350 (backing_object->type != OBJT_DEFAULT &&
1351 backing_object->type != OBJT_SWAP) ||
1352 (backing_object->flags & OBJ_DEAD) ||
1353 object->handle != NULL ||
1354 (object->type != OBJT_DEFAULT &&
1355 object->type != OBJT_SWAP) ||
1356 (object->flags & OBJ_DEAD)) {
1357 break;
1358 }
1359
1360 if (
1361 object->paging_in_progress != 0 ||
1362 backing_object->paging_in_progress != 0
1363 ) {
1364 vm_object_qcollapse(object);
1365 break;
1366 }
1367
1368 /*
1369 * We know that we can either collapse the backing object (if
1370 * the parent is the only reference to it) or (perhaps) have
1371 * the parent bypass the object if the parent happens to shadow
1372 * all the resident pages in the entire backing object.
1373 *
1374 * This is ignoring pager-backed pages such as swap pages.
1375 * vm_object_backing_scan fails the shadowing test in this
1376 * case.
1377 */
1378
1379 if (backing_object->ref_count == 1) {
1380 /*
1381 * If there is exactly one reference to the backing
1382 * object, we can collapse it into the parent.
1383 */
984263bc
MD
1384 vm_object_backing_scan(object, OBSC_COLLAPSE_WAIT);
1385
1386 /*
1387 * Move the pager from backing_object to object.
1388 */
1389
1390 if (backing_object->type == OBJT_SWAP) {
1391 vm_object_pip_add(backing_object, 1);
1392
1393 /*
1394 * scrap the paging_offset junk and do a
1395 * discrete copy. This also removes major
1396 * assumptions about how the swap-pager
1397 * works from where it doesn't belong. The
1398 * new swapper is able to optimize the
1399 * destroy-source case.
1400 */
1401
1402 vm_object_pip_add(object, 1);
1403 swap_pager_copy(
1404 backing_object,
1405 object,
1406 OFF_TO_IDX(object->backing_object_offset), TRUE);
1407 vm_object_pip_wakeup(object);
1408
1409 vm_object_pip_wakeup(backing_object);
1410 }
1411 /*
1412 * Object now shadows whatever backing_object did.
1413 * Note that the reference to
1414 * backing_object->backing_object moves from within
1415 * backing_object to within object.
1416 */
1417
1418 LIST_REMOVE(object, shadow_list);
1419 object->backing_object->shadow_count--;
1420 object->backing_object->generation++;
1421 if (backing_object->backing_object) {
1422 LIST_REMOVE(backing_object, shadow_list);
1423 backing_object->backing_object->shadow_count--;
1424 backing_object->backing_object->generation++;
1425 }
1426 object->backing_object = backing_object->backing_object;
1427 if (object->backing_object) {
1428 LIST_INSERT_HEAD(
1429 &object->backing_object->shadow_head,
1430 object,
1431 shadow_list
1432 );
1433 object->backing_object->shadow_count++;
1434 object->backing_object->generation++;
1435 }
1436
1437 object->backing_object_offset +=
1438 backing_object->backing_object_offset;
1439
1440 /*
1441 * Discard backing_object.
1442 *
1443 * Since the backing object has no pages, no pager left,
1444 * and no object references within it, all that is
1445 * necessary is to dispose of it.
1446 */
1447
1448 KASSERT(backing_object->ref_count == 1, ("backing_object %p was somehow re-referenced during collapse!", backing_object));
1f804340 1449 KASSERT(RB_EMPTY(&backing_object->rb_memq), ("backing_object %p somehow has left over pages during collapse!", backing_object));
fad57d0e 1450 crit_enter();
984263bc
MD
1451 TAILQ_REMOVE(
1452 &vm_object_list,
1453 backing_object,
1454 object_list
1455 );
1456 vm_object_count--;
fad57d0e 1457 crit_exit();
984263bc
MD
1458
1459 zfree(obj_zone, backing_object);
1460
1461 object_collapses++;
1462 } else {
1463 vm_object_t new_backing_object;
1464
1465 /*
1466 * If we do not entirely shadow the backing object,
1467 * there is nothing we can do so we give up.
1468 */
1469
1470 if (vm_object_backing_scan(object, OBSC_TEST_ALL_SHADOWED) == 0) {
1471 break;
1472 }
1473
1474 /*
1475 * Make the parent shadow the next object in the
1476 * chain. Deallocating backing_object will not remove
1477 * it, since its reference count is at least 2.
1478 */
1479
1480 LIST_REMOVE(object, shadow_list);
1481 backing_object->shadow_count--;
1482 backing_object->generation++;
1483
1484 new_backing_object = backing_object->backing_object;
1485 if ((object->backing_object = new_backing_object) != NULL) {
1486 vm_object_reference(new_backing_object);
1487 LIST_INSERT_HEAD(
1488 &new_backing_object->shadow_head,
1489 object,
1490 shadow_list
1491 );
1492 new_backing_object->shadow_count++;
1493 new_backing_object->generation++;
1494 object->backing_object_offset +=
1495 backing_object->backing_object_offset;
1496 }
1497
1498 /*
1499 * Drop the reference count on backing_object. Since
1500 * its ref_count was at least 2, it will not vanish;
1501 * so we don't need to call vm_object_deallocate, but
1502 * we do anyway.
1503 */
1504 vm_object_deallocate(backing_object);
1505 object_bypasses++;
1506 }
1507
1508 /*
1509 * Try again with this object's new backing object.
1510 */
1511 }
1512}
1513
1514/*
1515 * vm_object_page_remove: [internal]
1516 *
1517 * Removes all physical pages in the specified
1518 * object range from the object's list of pages.
984263bc 1519 */
1f804340
MD
1520static int vm_object_page_remove_callback(vm_page_t p, void *data);
1521
984263bc 1522void
57e43348 1523vm_object_page_remove(vm_object_t object, vm_pindex_t start, vm_pindex_t end,
1f804340 1524 boolean_t clean_only)
984263bc 1525{
1f804340 1526 struct rb_vm_page_scan_info info;
984263bc
MD
1527 int all;
1528
1f804340
MD
1529 /*
1530 * Degenerate cases and assertions
1531 */
06ecca5a 1532 if (object == NULL || object->resident_page_count == 0)
984263bc 1533 return;
1f804340
MD
1534 KASSERT(object->type != OBJT_PHYS,
1535 ("attempt to remove pages from a physical object"));
984263bc 1536
1f804340
MD
1537 /*
1538 * Indicate that paging is occuring on the object
1539 */
1540 crit_enter();
1541 vm_object_pip_add(object, 1);
984263bc
MD
1542
1543 /*
1f804340
MD
1544 * Figure out the actual removal range and whether we are removing
1545 * the entire contents of the object or not. If removing the entire
1546 * contents, be sure to get all pages, even those that might be
1547 * beyond the end of the object.
984263bc 1548 */
1f804340
MD
1549 info.start_pindex = start;
1550 if (end == 0)
1551 info.end_pindex = (vm_pindex_t)-1;
1552 else
1553 info.end_pindex = end - 1;
1554 info.limit = clean_only;
1555 all = (start == 0 && info.end_pindex >= object->size - 1);
984263bc 1556
06ecca5a 1557 /*
1f804340 1558 * Loop until we are sure we have gotten them all.
06ecca5a 1559 */
1f804340
MD
1560 do {
1561 info.error = 0;
1562 vm_page_rb_tree_RB_SCAN(&object->rb_memq, rb_vm_page_scancmp,
1563 vm_object_page_remove_callback, &info);
1564 } while (info.error);
984263bc 1565
1f804340 1566 /*
5ac04117
MD
1567 * Remove any related swap if throwing away pages, or for
1568 * non-swap objects (the swap is a clean copy in that case).
8d292090 1569 */
5ac04117 1570 if (object->type != OBJT_SWAP || clean_only == FALSE) {
8d292090
MD
1571 if (all)
1572 swap_pager_freespace_all(object);
1573 else
1574 swap_pager_freespace(object, info.start_pindex,
1575 info.end_pindex - info.start_pindex + 1);
1576 }
1577
1578 /*
1f804340
MD
1579 * Cleanup
1580 */
1581 vm_object_pip_wakeup(object);
1582 crit_exit();
1583}
984263bc 1584
1f804340
MD
1585static int
1586vm_object_page_remove_callback(vm_page_t p, void *data)
1587{
1588 struct rb_vm_page_scan_info *info = data;
984263bc 1589
1f804340
MD
1590 /*
1591 * Wired pages cannot be destroyed, but they can be invalidated
1592 * and we do so if clean_only (limit) is not set.
1c9602b3
MD
1593 *
1594 * WARNING! The page may be wired due to being part of a buffer
1595 * cache buffer, and the buffer might be marked B_CACHE.
1596 * This is fine as part of a truncation but VFSs must be
1597 * sure to fix the buffer up when re-extending the file.
1f804340
MD
1598 */
1599 if (p->wire_count != 0) {
1600 vm_page_protect(p, VM_PROT_NONE);
1601 if (info->limit == 0)
1602 p->valid = 0;
1603 return(0);
1604 }
984263bc 1605
1f804340
MD
1606 /*
1607 * The busy flags are only cleared at
1608 * interrupt -- minimize the spl transitions
1609 */
984263bc 1610
1f804340
MD
1611 if (vm_page_sleep_busy(p, TRUE, "vmopar")) {
1612 info->error = 1;
1613 return(0);
1614 }
984263bc 1615
1f804340
MD
1616 /*
1617 * limit is our clean_only flag. If set and the page is dirty, do
d309a59d 1618 * not free it. If set and the page is being held by someone, do
1f804340
MD
1619 * not free it.
1620 */
1621 if (info->limit && p->valid) {
1622 vm_page_test_dirty(p);
1623 if (p->valid & p->dirty)
1624 return(0);
d309a59d
MD
1625 if (p->hold_count)
1626 return(0);
984263bc 1627 }
1f804340
MD
1628
1629 /*
1630 * Destroy the page
1631 */
1632 vm_page_busy(p);
1633 vm_page_protect(p, VM_PROT_NONE);
1634 vm_page_free(p);
1635 return(0);
984263bc
MD
1636}
1637
1638/*
1639 * Routine: vm_object_coalesce
1640 * Function: Coalesces two objects backing up adjoining
1641 * regions of memory into a single object.
1642 *
1643 * returns TRUE if objects were combined.
1644 *
1645 * NOTE: Only works at the moment if the second object is NULL -
1646 * if it's not, which object do we lock first?
1647 *
1648 * Parameters:
1649 * prev_object First object to coalesce
1650 * prev_offset Offset into prev_object
1651 * next_object Second object into coalesce
1652 * next_offset Offset into next_object
1653 *
1654 * prev_size Size of reference to prev_object
1655 * next_size Size of reference to next_object
1656 *
1657 * Conditions:
1658 * The object must *not* be locked.
1659 */
1660boolean_t
57e43348 1661vm_object_coalesce(vm_object_t prev_object, vm_pindex_t prev_pindex,
8d292090 1662 vm_size_t prev_size, vm_size_t next_size)
984263bc
MD
1663{
1664 vm_pindex_t next_pindex;
1665
1666 if (prev_object == NULL) {
1667 return (TRUE);
1668 }
1669
1670 if (prev_object->type != OBJT_DEFAULT &&
1671 prev_object->type != OBJT_SWAP) {
1672 return (FALSE);
1673 }
1674
1675 /*
1676 * Try to collapse the object first
1677 */
1678 vm_object_collapse(prev_object);
1679
1680 /*
1681 * Can't coalesce if: . more than one reference . paged out . shadows
1682 * another object . has a copy elsewhere (any of which mean that the
1683 * pages not mapped to prev_entry may be in use anyway)
1684 */
1685
1686 if (prev_object->backing_object != NULL) {
1687 return (FALSE);
1688 }
1689
1690 prev_size >>= PAGE_SHIFT;
1691 next_size >>= PAGE_SHIFT;
1692 next_pindex = prev_pindex + prev_size;
1693
1694 if ((prev_object->ref_count > 1) &&
1695 (prev_object->size != next_pindex)) {
1696 return (FALSE);
1697 }
1698
1699 /*
1700 * Remove any pages that may still be in the object from a previous
1701 * deallocation.
1702 */
1703 if (next_pindex < prev_object->size) {
1704 vm_object_page_remove(prev_object,
1705 next_pindex,
1706 next_pindex + next_size, FALSE);
1707 if (prev_object->type == OBJT_SWAP)
1708 swap_pager_freespace(prev_object,
1709 next_pindex, next_size);
1710 }
1711
1712 /*
1713 * Extend the object if necessary.
1714 */
1715 if (next_pindex + next_size > prev_object->size)
1716 prev_object->size = next_pindex + next_size;
1717
1718 return (TRUE);
1719}
1720
1721void
1722vm_object_set_writeable_dirty(vm_object_t object)
1723{
1724 struct vnode *vp;
1725
1726 vm_object_set_flag(object, OBJ_WRITEABLE|OBJ_MIGHTBEDIRTY);
1727 if (object->type == OBJT_VNODE &&
1728 (vp = (struct vnode *)object->handle) != NULL) {
1729 if ((vp->v_flag & VOBJDIRTY) == 0) {
5fd012e0 1730 vsetflags(vp, VOBJDIRTY);
984263bc
MD
1731 }
1732 }
1733}
1734
1735
1736
1737#include "opt_ddb.h"
1738#ifdef DDB
1739#include <sys/kernel.h>
1740
1741#include <sys/cons.h>
1742
1743#include <ddb/ddb.h>
1744
1388df65
RG
1745static int _vm_object_in_map (vm_map_t map, vm_object_t object,
1746 vm_map_entry_t entry);
1747static int vm_object_in_map (vm_object_t object);
984263bc
MD
1748
1749static int
57e43348 1750_vm_object_in_map(vm_map_t map, vm_object_t object, vm_map_entry_t entry)
984263bc
MD
1751{
1752 vm_map_t tmpm;
1753 vm_map_entry_t tmpe;
1754 vm_object_t obj;
1755 int entcount;
1756
1757 if (map == 0)
1758 return 0;
984263bc
MD
1759 if (entry == 0) {
1760 tmpe = map->header.next;
1761 entcount = map->nentries;
1762 while (entcount-- && (tmpe != &map->header)) {
1763 if( _vm_object_in_map(map, object, tmpe)) {
1764 return 1;
1765 }
1766 tmpe = tmpe->next;
1767 }
1b874851
MD
1768 return (0);
1769 }
1770 switch(entry->maptype) {
1771 case VM_MAPTYPE_SUBMAP:
984263bc
MD
1772 tmpm = entry->object.sub_map;
1773 tmpe = tmpm->header.next;
1774 entcount = tmpm->nentries;
1775 while (entcount-- && tmpe != &tmpm->header) {
1776 if( _vm_object_in_map(tmpm, object, tmpe)) {
1777 return 1;
1778 }
1779 tmpe = tmpe->next;
1780 }
1b874851
MD
1781 break;
1782 case VM_MAPTYPE_NORMAL:
1783 case VM_MAPTYPE_VPAGETABLE:
1784 obj = entry->object.vm_object;
1785 while (obj) {
1786 if (obj == object)
984263bc 1787 return 1;
1b874851
MD
1788 obj = obj->backing_object;
1789 }
1790 break;
1791 default:
1792 break;
984263bc
MD
1793 }
1794 return 0;
1795}
1796
8fa76237
MD
1797static int vm_object_in_map_callback(struct proc *p, void *data);
1798
1799struct vm_object_in_map_info {
1800 vm_object_t object;
1801 int rv;
1802};
1803
984263bc 1804static int
57e43348 1805vm_object_in_map(vm_object_t object)
984263bc 1806{
8fa76237
MD
1807 struct vm_object_in_map_info info;
1808
1809 info.rv = 0;
1810 info.object = object;
1811
1812 allproc_scan(vm_object_in_map_callback, &info);
1813 if (info.rv)
1814 return 1;
e4846942 1815 if( _vm_object_in_map(&kernel_map, object, 0))
984263bc 1816 return 1;
e4846942 1817 if( _vm_object_in_map(&pager_map, object, 0))
984263bc 1818 return 1;
e4846942 1819 if( _vm_object_in_map(&buffer_map, object, 0))
984263bc 1820 return 1;
984263bc
MD
1821 return 0;
1822}
1823
8fa76237
MD
1824static int
1825vm_object_in_map_callback(struct proc *p, void *data)
1826{
1827 struct vm_object_in_map_info *info = data;
1828
1829 if (p->p_vmspace) {
1830 if (_vm_object_in_map(&p->p_vmspace->vm_map, info->object, 0)) {
1831 info->rv = 1;
1832 return -1;
1833 }
1834 }
1835 return (0);
1836}
1837
984263bc
MD
1838DB_SHOW_COMMAND(vmochk, vm_object_check)
1839{
1840 vm_object_t object;
1841
1842 /*
1843 * make sure that internal objs are in a map somewhere
1844 * and none have zero ref counts.
1845 */
1846 for (object = TAILQ_FIRST(&vm_object_list);
1847 object != NULL;
1848 object = TAILQ_NEXT(object, object_list)) {
1849 if (object->handle == NULL &&
1850 (object->type == OBJT_DEFAULT || object->type == OBJT_SWAP)) {
1851 if (object->ref_count == 0) {
1852 db_printf("vmochk: internal obj has zero ref count: %ld\n",
1853 (long)object->size);
1854 }
1855 if (!vm_object_in_map(object)) {
1856 db_printf(
1857 "vmochk: internal obj is not in a map: "
1858 "ref: %d, size: %lu: 0x%lx, backing_object: %p\n",
1859 object->ref_count, (u_long)object->size,
1860 (u_long)object->size,
1861 (void *)object->backing_object);
1862 }
1863 }
1864 }
1865}
1866
1867/*
1868 * vm_object_print: [ debug ]
1869 */
1870DB_SHOW_COMMAND(object, vm_object_print_static)
1871{
1872 /* XXX convert args. */
1873 vm_object_t object = (vm_object_t)addr;
1874 boolean_t full = have_addr;
1875
1876 vm_page_t p;
1877
1878 /* XXX count is an (unused) arg. Avoid shadowing it. */
1879#define count was_count
1880
1881 int count;
1882
1883 if (object == NULL)
1884 return;
1885
1886 db_iprintf(
1887 "Object %p: type=%d, size=0x%lx, res=%d, ref=%d, flags=0x%x\n",
1888 object, (int)object->type, (u_long)object->size,
1889 object->resident_page_count, object->ref_count, object->flags);
1890 /*
1891 * XXX no %qd in kernel. Truncate object->backing_object_offset.
1892 */
1893 db_iprintf(" sref=%d, backing_object(%d)=(%p)+0x%lx\n",
1894 object->shadow_count,
1895 object->backing_object ? object->backing_object->ref_count : 0,
1896 object->backing_object, (long)object->backing_object_offset);
1897
1898 if (!full)
1899 return;
1900
1901 db_indent += 2;
1902 count = 0;
1f804340 1903 RB_FOREACH(p, vm_page_rb_tree, &object->rb_memq) {
984263bc
MD
1904 if (count == 0)
1905 db_iprintf("memory:=");
1906 else if (count == 6) {
1907 db_printf("\n");
1908 db_iprintf(" ...");
1909 count = 0;
1910 } else
1911 db_printf(",");
1912 count++;
1913
1914 db_printf("(off=0x%lx,page=0x%lx)",
1915 (u_long) p->pindex, (u_long) VM_PAGE_TO_PHYS(p));
1916 }
1917 if (count != 0)
1918 db_printf("\n");
1919 db_indent -= 2;
1920}
1921
1922/* XXX. */
1923#undef count
1924
1925/* XXX need this non-static entry for calling from vm_map_print. */
1926void
57e43348
MD
1927vm_object_print(/* db_expr_t */ long addr,
1928 boolean_t have_addr,
1929 /* db_expr_t */ long count,
1930 char *modif)
984263bc
MD
1931{
1932 vm_object_print_static(addr, have_addr, count, modif);
1933}
1934
1935DB_SHOW_COMMAND(vmopag, vm_object_print_pages)
1936{
1937 vm_object_t object;
1938 int nl = 0;
1939 int c;
1940 for (object = TAILQ_FIRST(&vm_object_list);
1941 object != NULL;
1942 object = TAILQ_NEXT(object, object_list)) {
1943 vm_pindex_t idx, fidx;
1944 vm_pindex_t osize;
6ef943a3 1945 vm_paddr_t pa = -1, padiff;
984263bc
MD
1946 int rcount;
1947 vm_page_t m;
1948
1949 db_printf("new object: %p\n", (void *)object);
1950 if ( nl > 18) {
1951 c = cngetc();
1952 if (c != ' ')
1953 return;
1954 nl = 0;
1955 }
1956 nl++;
1957 rcount = 0;
1958 fidx = 0;
1959 osize = object->size;
1960 if (osize > 128)
1961 osize = 128;
06ecca5a 1962 for (idx = 0; idx < osize; idx++) {
984263bc
MD
1963 m = vm_page_lookup(object, idx);
1964 if (m == NULL) {
1965 if (rcount) {
1966 db_printf(" index(%ld)run(%d)pa(0x%lx)\n",
1967 (long)fidx, rcount, (long)pa);
1968 if ( nl > 18) {
1969 c = cngetc();
1970 if (c != ' ')
1971 return;
1972 nl = 0;
1973 }
1974 nl++;
1975 rcount = 0;
1976 }
1977 continue;
1978 }
1979
1980
1981 if (rcount &&
1982 (VM_PAGE_TO_PHYS(m) == pa + rcount * PAGE_SIZE)) {
1983 ++rcount;
1984 continue;
1985 }
1986 if (rcount) {
1987 padiff = pa + rcount * PAGE_SIZE - VM_PAGE_TO_PHYS(m);
1988 padiff >>= PAGE_SHIFT;
1989 padiff &= PQ_L2_MASK;
1990 if (padiff == 0) {
1991 pa = VM_PAGE_TO_PHYS(m) - rcount * PAGE_SIZE;
1992 ++rcount;
1993 continue;
1994 }
1995 db_printf(" index(%ld)run(%d)pa(0x%lx)",
1996 (long)fidx, rcount, (long)pa);
1997 db_printf("pd(%ld)\n", (long)padiff);
1998 if ( nl > 18) {
1999 c = cngetc();
2000 if (c != ' ')
2001 return;
2002 nl = 0;
2003 }
2004 nl++;
2005 }
2006 fidx = idx;
2007 pa = VM_PAGE_TO_PHYS(m);
2008 rcount = 1;
2009 }
2010 if (rcount) {
2011 db_printf(" index(%ld)run(%d)pa(0x%lx)\n",
2012 (long)fidx, rcount, (long)pa);
2013 if ( nl > 18) {
2014 c = cngetc();
2015 if (c != ' ')
2016 return;
2017 nl = 0;
2018 }
2019 nl++;
2020 }
2021 }
2022}
2023#endif /* DDB */