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b688fc87 WJ |
1 | /* |
2 | * Copyright (c) 1991 Regents of the University of California. | |
3 | * 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 | * @(#)vm_object.c 7.4 (Berkeley) 5/7/91 | |
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 | ||
65 | /* | |
66 | * Virtual memory object module. | |
67 | */ | |
68 | ||
69 | #include "param.h" | |
70 | #include "malloc.h" | |
71 | ||
72 | #include "vm.h" | |
73 | #include "vm_page.h" | |
74 | ||
75 | /* | |
76 | * Virtual memory objects maintain the actual data | |
77 | * associated with allocated virtual memory. A given | |
78 | * page of memory exists within exactly one object. | |
79 | * | |
80 | * An object is only deallocated when all "references" | |
81 | * are given up. Only one "reference" to a given | |
82 | * region of an object should be writeable. | |
83 | * | |
84 | * Associated with each object is a list of all resident | |
85 | * memory pages belonging to that object; this list is | |
86 | * maintained by the "vm_page" module, and locked by the object's | |
87 | * lock. | |
88 | * | |
89 | * Each object also records a "pager" routine which is | |
90 | * used to retrieve (and store) pages to the proper backing | |
91 | * storage. In addition, objects may be backed by other | |
92 | * objects from which they were virtual-copied. | |
93 | * | |
94 | * The only items within the object structure which are | |
95 | * modified after time of creation are: | |
96 | * reference count locked by object's lock | |
97 | * pager routine locked by object's lock | |
98 | * | |
99 | */ | |
100 | ||
101 | struct vm_object kernel_object_store; | |
102 | struct vm_object kmem_object_store; | |
103 | ||
104 | #define VM_OBJECT_HASH_COUNT 157 | |
105 | ||
106 | int vm_cache_max = 100; /* can patch if necessary */ | |
107 | queue_head_t vm_object_hashtable[VM_OBJECT_HASH_COUNT]; | |
108 | ||
109 | long object_collapses = 0; | |
110 | long object_bypasses = 0; | |
111 | ||
112 | /* | |
113 | * vm_object_init: | |
114 | * | |
115 | * Initialize the VM objects module. | |
116 | */ | |
117 | void vm_object_init() | |
118 | { | |
119 | register int i; | |
120 | ||
121 | queue_init(&vm_object_cached_list); | |
122 | queue_init(&vm_object_list); | |
123 | vm_object_count = 0; | |
124 | simple_lock_init(&vm_cache_lock); | |
125 | simple_lock_init(&vm_object_list_lock); | |
126 | ||
127 | for (i = 0; i < VM_OBJECT_HASH_COUNT; i++) | |
128 | queue_init(&vm_object_hashtable[i]); | |
129 | ||
130 | kernel_object = &kernel_object_store; | |
131 | _vm_object_allocate(VM_MAX_KERNEL_ADDRESS - VM_MIN_KERNEL_ADDRESS, | |
132 | kernel_object); | |
133 | ||
134 | kmem_object = &kmem_object_store; | |
135 | _vm_object_allocate(VM_KMEM_SIZE + VM_MBUF_SIZE, kmem_object); | |
136 | } | |
137 | ||
138 | /* | |
139 | * vm_object_allocate: | |
140 | * | |
141 | * Returns a new object with the given size. | |
142 | */ | |
143 | ||
144 | vm_object_t vm_object_allocate(size) | |
145 | vm_size_t size; | |
146 | { | |
147 | register vm_object_t result; | |
148 | ||
149 | result = (vm_object_t) | |
150 | malloc((u_long)sizeof *result, M_VMOBJ, M_WAITOK); | |
151 | ||
152 | _vm_object_allocate(size, result); | |
153 | ||
154 | return(result); | |
155 | } | |
156 | ||
157 | _vm_object_allocate(size, object) | |
158 | vm_size_t size; | |
159 | register vm_object_t object; | |
160 | { | |
161 | queue_init(&object->memq); | |
162 | vm_object_lock_init(object); | |
163 | object->ref_count = 1; | |
164 | object->resident_page_count = 0; | |
165 | object->size = size; | |
166 | object->can_persist = FALSE; | |
167 | object->paging_in_progress = 0; | |
168 | object->copy = NULL; | |
169 | ||
170 | /* | |
171 | * Object starts out read-write, with no pager. | |
172 | */ | |
173 | ||
174 | object->pager = NULL; | |
175 | object->pager_ready = FALSE; | |
176 | object->internal = TRUE; /* vm_allocate_with_pager will reset */ | |
177 | object->paging_offset = 0; | |
178 | object->shadow = NULL; | |
179 | object->shadow_offset = (vm_offset_t) 0; | |
180 | ||
181 | simple_lock(&vm_object_list_lock); | |
182 | queue_enter(&vm_object_list, object, vm_object_t, object_list); | |
183 | vm_object_count++; | |
184 | simple_unlock(&vm_object_list_lock); | |
185 | } | |
186 | ||
187 | /* | |
188 | * vm_object_reference: | |
189 | * | |
190 | * Gets another reference to the given object. | |
191 | */ | |
192 | void vm_object_reference(object) | |
193 | register vm_object_t object; | |
194 | { | |
195 | if (object == NULL) | |
196 | return; | |
197 | ||
198 | vm_object_lock(object); | |
199 | object->ref_count++; | |
200 | vm_object_unlock(object); | |
201 | } | |
202 | ||
203 | /* | |
204 | * vm_object_deallocate: | |
205 | * | |
206 | * Release a reference to the specified object, | |
207 | * gained either through a vm_object_allocate | |
208 | * or a vm_object_reference call. When all references | |
209 | * are gone, storage associated with this object | |
210 | * may be relinquished. | |
211 | * | |
212 | * No object may be locked. | |
213 | */ | |
214 | void vm_object_deallocate(object) | |
215 | register vm_object_t object; | |
216 | { | |
217 | vm_object_t temp; | |
218 | ||
219 | while (object != NULL) { | |
220 | ||
221 | /* | |
222 | * The cache holds a reference (uncounted) to | |
223 | * the object; we must lock it before removing | |
224 | * the object. | |
225 | */ | |
226 | ||
227 | vm_object_cache_lock(); | |
228 | ||
229 | /* | |
230 | * Lose the reference | |
231 | */ | |
232 | vm_object_lock(object); | |
233 | if (--(object->ref_count) != 0) { | |
234 | ||
235 | /* | |
236 | * If there are still references, then | |
237 | * we are done. | |
238 | */ | |
239 | vm_object_unlock(object); | |
240 | vm_object_cache_unlock(); | |
241 | return; | |
242 | } | |
243 | ||
244 | /* | |
245 | * See if this object can persist. If so, enter | |
246 | * it in the cache, then deactivate all of its | |
247 | * pages. | |
248 | */ | |
249 | ||
250 | if (object->can_persist) { | |
251 | ||
252 | queue_enter(&vm_object_cached_list, object, | |
253 | vm_object_t, cached_list); | |
254 | vm_object_cached++; | |
255 | vm_object_cache_unlock(); | |
256 | ||
257 | vm_object_deactivate_pages(object); | |
258 | vm_object_unlock(object); | |
259 | ||
260 | vm_object_cache_trim(); | |
261 | return; | |
262 | } | |
263 | ||
264 | /* | |
265 | * Make sure no one can look us up now. | |
266 | */ | |
267 | vm_object_remove(object->pager); | |
268 | vm_object_cache_unlock(); | |
269 | ||
270 | temp = object->shadow; | |
271 | vm_object_terminate(object); | |
272 | /* unlocks and deallocates object */ | |
273 | object = temp; | |
274 | } | |
275 | } | |
276 | ||
277 | ||
278 | /* | |
279 | * vm_object_terminate actually destroys the specified object, freeing | |
280 | * up all previously used resources. | |
281 | * | |
282 | * The object must be locked. | |
283 | */ | |
284 | void vm_object_terminate(object) | |
285 | register vm_object_t object; | |
286 | { | |
287 | register vm_page_t p; | |
288 | vm_object_t shadow_object; | |
289 | ||
290 | /* | |
291 | * Detach the object from its shadow if we are the shadow's | |
292 | * copy. | |
293 | */ | |
294 | if ((shadow_object = object->shadow) != NULL) { | |
295 | vm_object_lock(shadow_object); | |
296 | if (shadow_object->copy == object) | |
297 | shadow_object->copy = NULL; | |
298 | #if 0 | |
299 | else if (shadow_object->copy != NULL) | |
300 | panic("vm_object_terminate: copy/shadow inconsistency"); | |
301 | #endif | |
302 | vm_object_unlock(shadow_object); | |
303 | } | |
304 | ||
305 | /* | |
306 | * Wait until the pageout daemon is through | |
307 | * with the object. | |
308 | */ | |
309 | ||
310 | while (object->paging_in_progress != 0) { | |
311 | vm_object_sleep(object, object, FALSE); | |
312 | vm_object_lock(object); | |
313 | } | |
314 | ||
315 | ||
316 | /* | |
317 | * While the paging system is locked, | |
318 | * pull the object's pages off the active | |
319 | * and inactive queues. This keeps the | |
320 | * pageout daemon from playing with them | |
321 | * during vm_pager_deallocate. | |
322 | * | |
323 | * We can't free the pages yet, because the | |
324 | * object's pager may have to write them out | |
325 | * before deallocating the paging space. | |
326 | */ | |
327 | ||
328 | p = (vm_page_t) queue_first(&object->memq); | |
329 | while (!queue_end(&object->memq, (queue_entry_t) p)) { | |
330 | VM_PAGE_CHECK(p); | |
331 | ||
332 | vm_page_lock_queues(); | |
333 | if (p->active) { | |
334 | queue_remove(&vm_page_queue_active, p, vm_page_t, | |
335 | pageq); | |
336 | p->active = FALSE; | |
337 | vm_page_active_count--; | |
338 | } | |
339 | ||
340 | if (p->inactive) { | |
341 | queue_remove(&vm_page_queue_inactive, p, vm_page_t, | |
342 | pageq); | |
343 | p->inactive = FALSE; | |
344 | vm_page_inactive_count--; | |
345 | } | |
346 | vm_page_unlock_queues(); | |
347 | p = (vm_page_t) queue_next(&p->listq); | |
348 | } | |
349 | ||
350 | vm_object_unlock(object); | |
351 | ||
352 | if (object->paging_in_progress != 0) | |
353 | panic("vm_object_deallocate: pageout in progress"); | |
354 | ||
355 | /* | |
356 | * Clean and free the pages, as appropriate. | |
357 | * All references to the object are gone, | |
358 | * so we don't need to lock it. | |
359 | */ | |
360 | ||
361 | if (!object->internal) { | |
362 | vm_object_lock(object); | |
363 | vm_object_page_clean(object, 0, 0); | |
364 | vm_object_unlock(object); | |
365 | } | |
366 | while (!queue_empty(&object->memq)) { | |
367 | p = (vm_page_t) queue_first(&object->memq); | |
368 | ||
369 | VM_PAGE_CHECK(p); | |
370 | ||
371 | vm_page_lock_queues(); | |
372 | vm_page_free(p); | |
373 | vm_page_unlock_queues(); | |
374 | } | |
375 | ||
376 | /* | |
377 | * Let the pager know object is dead. | |
378 | */ | |
379 | ||
380 | if (object->pager != NULL) | |
381 | vm_pager_deallocate(object->pager); | |
382 | ||
383 | ||
384 | simple_lock(&vm_object_list_lock); | |
385 | queue_remove(&vm_object_list, object, vm_object_t, object_list); | |
386 | vm_object_count--; | |
387 | simple_unlock(&vm_object_list_lock); | |
388 | ||
389 | /* | |
390 | * Free the space for the object. | |
391 | */ | |
392 | ||
393 | free((caddr_t)object, M_VMOBJ); | |
394 | } | |
395 | ||
396 | /* | |
397 | * vm_object_page_clean | |
398 | * | |
399 | * Clean all dirty pages in the specified range of object. | |
400 | * Leaves page on whatever queue it is currently on. | |
401 | * | |
402 | * Odd semantics: if start == end, we clean everything. | |
403 | * | |
404 | * The object must be locked. | |
405 | */ | |
406 | vm_object_page_clean(object, start, end) | |
407 | register vm_object_t object; | |
408 | register vm_offset_t start; | |
409 | register vm_offset_t end; | |
410 | { | |
411 | register vm_page_t p; | |
412 | ||
413 | if (object->pager == NULL) | |
414 | return; | |
415 | ||
416 | again: | |
417 | p = (vm_page_t) queue_first(&object->memq); | |
418 | while (!queue_end(&object->memq, (queue_entry_t) p)) { | |
419 | if (start == end || | |
420 | p->offset >= start && p->offset < end) { | |
421 | if (p->clean && pmap_is_modified(VM_PAGE_TO_PHYS(p))) | |
422 | p->clean = FALSE; | |
423 | pmap_page_protect(VM_PAGE_TO_PHYS(p), VM_PROT_NONE); | |
424 | if (!p->clean) { | |
425 | p->busy = TRUE; | |
426 | object->paging_in_progress++; | |
427 | vm_object_unlock(object); | |
428 | (void) vm_pager_put(object->pager, p, TRUE); | |
429 | vm_object_lock(object); | |
430 | object->paging_in_progress--; | |
431 | p->busy = FALSE; | |
432 | PAGE_WAKEUP(p); | |
433 | goto again; | |
434 | } | |
435 | } | |
436 | p = (vm_page_t) queue_next(&p->listq); | |
437 | } | |
438 | } | |
439 | ||
440 | /* | |
441 | * vm_object_deactivate_pages | |
442 | * | |
443 | * Deactivate all pages in the specified object. (Keep its pages | |
444 | * in memory even though it is no longer referenced.) | |
445 | * | |
446 | * The object must be locked. | |
447 | */ | |
448 | vm_object_deactivate_pages(object) | |
449 | register vm_object_t object; | |
450 | { | |
451 | register vm_page_t p, next; | |
452 | ||
453 | p = (vm_page_t) queue_first(&object->memq); | |
454 | while (!queue_end(&object->memq, (queue_entry_t) p)) { | |
455 | next = (vm_page_t) queue_next(&p->listq); | |
456 | vm_page_lock_queues(); | |
457 | vm_page_deactivate(p); | |
458 | vm_page_unlock_queues(); | |
459 | p = next; | |
460 | } | |
461 | } | |
462 | ||
463 | /* | |
464 | * Trim the object cache to size. | |
465 | */ | |
466 | vm_object_cache_trim() | |
467 | { | |
468 | register vm_object_t object; | |
469 | ||
470 | vm_object_cache_lock(); | |
471 | while (vm_object_cached > vm_cache_max) { | |
472 | object = (vm_object_t) queue_first(&vm_object_cached_list); | |
473 | vm_object_cache_unlock(); | |
474 | ||
475 | if (object != vm_object_lookup(object->pager)) | |
476 | panic("vm_object_deactivate: I'm sooo confused."); | |
477 | ||
478 | pager_cache(object, FALSE); | |
479 | ||
480 | vm_object_cache_lock(); | |
481 | } | |
482 | vm_object_cache_unlock(); | |
483 | } | |
484 | ||
485 | ||
486 | /* | |
487 | * vm_object_shutdown() | |
488 | * | |
489 | * Shut down the object system. Unfortunately, while we | |
490 | * may be trying to do this, init is happily waiting for | |
491 | * processes to exit, and therefore will be causing some objects | |
492 | * to be deallocated. To handle this, we gain a fake reference | |
493 | * to all objects we release paging areas for. This will prevent | |
494 | * a duplicate deallocation. This routine is probably full of | |
495 | * race conditions! | |
496 | */ | |
497 | ||
498 | void vm_object_shutdown() | |
499 | { | |
500 | register vm_object_t object; | |
501 | ||
502 | /* | |
503 | * Clean up the object cache *before* we screw up the reference | |
504 | * counts on all of the objects. | |
505 | */ | |
506 | ||
507 | vm_object_cache_clear(); | |
508 | ||
509 | printf("free paging spaces: "); | |
510 | ||
511 | /* | |
512 | * First we gain a reference to each object so that | |
513 | * no one else will deallocate them. | |
514 | */ | |
515 | ||
516 | simple_lock(&vm_object_list_lock); | |
517 | object = (vm_object_t) queue_first(&vm_object_list); | |
518 | while (!queue_end(&vm_object_list, (queue_entry_t) object)) { | |
519 | vm_object_reference(object); | |
520 | object = (vm_object_t) queue_next(&object->object_list); | |
521 | } | |
522 | simple_unlock(&vm_object_list_lock); | |
523 | ||
524 | /* | |
525 | * Now we deallocate all the paging areas. We don't need | |
526 | * to lock anything because we've reduced to a single | |
527 | * processor while shutting down. This also assumes that | |
528 | * no new objects are being created. | |
529 | */ | |
530 | ||
531 | object = (vm_object_t) queue_first(&vm_object_list); | |
532 | while (!queue_end(&vm_object_list, (queue_entry_t) object)) { | |
533 | if (object->pager != NULL) | |
534 | vm_pager_deallocate(object->pager); | |
535 | object = (vm_object_t) queue_next(&object->object_list); | |
536 | printf("."); | |
537 | } | |
538 | printf("done.\n"); | |
539 | } | |
540 | ||
541 | /* | |
542 | * vm_object_pmap_copy: | |
543 | * | |
544 | * Makes all physical pages in the specified | |
545 | * object range copy-on-write. No writeable | |
546 | * references to these pages should remain. | |
547 | * | |
548 | * The object must *not* be locked. | |
549 | */ | |
550 | void vm_object_pmap_copy(object, start, end) | |
551 | register vm_object_t object; | |
552 | register vm_offset_t start; | |
553 | register vm_offset_t end; | |
554 | { | |
555 | register vm_page_t p; | |
556 | ||
557 | if (object == NULL) | |
558 | return; | |
559 | ||
560 | vm_object_lock(object); | |
561 | p = (vm_page_t) queue_first(&object->memq); | |
562 | while (!queue_end(&object->memq, (queue_entry_t) p)) { | |
563 | if ((start <= p->offset) && (p->offset < end)) { | |
564 | pmap_page_protect(VM_PAGE_TO_PHYS(p), VM_PROT_READ); | |
565 | p->copy_on_write = TRUE; | |
566 | } | |
567 | p = (vm_page_t) queue_next(&p->listq); | |
568 | } | |
569 | vm_object_unlock(object); | |
570 | } | |
571 | ||
572 | /* | |
573 | * vm_object_pmap_remove: | |
574 | * | |
575 | * Removes all physical pages in the specified | |
576 | * object range from all physical maps. | |
577 | * | |
578 | * The object must *not* be locked. | |
579 | */ | |
580 | void vm_object_pmap_remove(object, start, end) | |
581 | register vm_object_t object; | |
582 | register vm_offset_t start; | |
583 | register vm_offset_t end; | |
584 | { | |
585 | register vm_page_t p; | |
586 | ||
587 | if (object == NULL) | |
588 | return; | |
589 | ||
590 | vm_object_lock(object); | |
591 | p = (vm_page_t) queue_first(&object->memq); | |
592 | while (!queue_end(&object->memq, (queue_entry_t) p)) { | |
593 | if ((start <= p->offset) && (p->offset < end)) | |
594 | pmap_page_protect(VM_PAGE_TO_PHYS(p), VM_PROT_NONE); | |
595 | p = (vm_page_t) queue_next(&p->listq); | |
596 | } | |
597 | vm_object_unlock(object); | |
598 | } | |
599 | ||
600 | /* | |
601 | * vm_object_copy: | |
602 | * | |
603 | * Create a new object which is a copy of an existing | |
604 | * object, and mark all of the pages in the existing | |
605 | * object 'copy-on-write'. The new object has one reference. | |
606 | * Returns the new object. | |
607 | * | |
608 | * May defer the copy until later if the object is not backed | |
609 | * up by a non-default pager. | |
610 | */ | |
611 | void vm_object_copy(src_object, src_offset, size, | |
612 | dst_object, dst_offset, src_needs_copy) | |
613 | register vm_object_t src_object; | |
614 | vm_offset_t src_offset; | |
615 | vm_size_t size; | |
616 | vm_object_t *dst_object; /* OUT */ | |
617 | vm_offset_t *dst_offset; /* OUT */ | |
618 | boolean_t *src_needs_copy; /* OUT */ | |
619 | { | |
620 | register vm_object_t new_copy; | |
621 | register vm_object_t old_copy; | |
622 | vm_offset_t new_start, new_end; | |
623 | ||
624 | register vm_page_t p; | |
625 | ||
626 | if (src_object == NULL) { | |
627 | /* | |
628 | * Nothing to copy | |
629 | */ | |
630 | *dst_object = NULL; | |
631 | *dst_offset = 0; | |
632 | *src_needs_copy = FALSE; | |
633 | return; | |
634 | } | |
635 | ||
636 | /* | |
637 | * If the object's pager is null_pager or the | |
638 | * default pager, we don't have to make a copy | |
639 | * of it. Instead, we set the needs copy flag and | |
640 | * make a shadow later. | |
641 | */ | |
642 | ||
643 | vm_object_lock(src_object); | |
644 | if (src_object->pager == NULL || | |
645 | src_object->internal) { | |
646 | ||
647 | /* | |
648 | * Make another reference to the object | |
649 | */ | |
650 | src_object->ref_count++; | |
651 | ||
652 | /* | |
653 | * Mark all of the pages copy-on-write. | |
654 | */ | |
655 | for (p = (vm_page_t) queue_first(&src_object->memq); | |
656 | !queue_end(&src_object->memq, (queue_entry_t)p); | |
657 | p = (vm_page_t) queue_next(&p->listq)) { | |
658 | if (src_offset <= p->offset && | |
659 | p->offset < src_offset + size) | |
660 | p->copy_on_write = TRUE; | |
661 | } | |
662 | vm_object_unlock(src_object); | |
663 | ||
664 | *dst_object = src_object; | |
665 | *dst_offset = src_offset; | |
666 | ||
667 | /* | |
668 | * Must make a shadow when write is desired | |
669 | */ | |
670 | *src_needs_copy = TRUE; | |
671 | return; | |
672 | } | |
673 | ||
674 | /* | |
675 | * Try to collapse the object before copying it. | |
676 | */ | |
677 | vm_object_collapse(src_object); | |
678 | ||
679 | /* | |
680 | * If the object has a pager, the pager wants to | |
681 | * see all of the changes. We need a copy-object | |
682 | * for the changed pages. | |
683 | * | |
684 | * If there is a copy-object, and it is empty, | |
685 | * no changes have been made to the object since the | |
686 | * copy-object was made. We can use the same copy- | |
687 | * object. | |
688 | */ | |
689 | ||
690 | Retry1: | |
691 | old_copy = src_object->copy; | |
692 | if (old_copy != NULL) { | |
693 | /* | |
694 | * Try to get the locks (out of order) | |
695 | */ | |
696 | if (!vm_object_lock_try(old_copy)) { | |
697 | vm_object_unlock(src_object); | |
698 | ||
699 | /* should spin a bit here... */ | |
700 | vm_object_lock(src_object); | |
701 | goto Retry1; | |
702 | } | |
703 | ||
704 | if (old_copy->resident_page_count == 0 && | |
705 | old_copy->pager == NULL) { | |
706 | /* | |
707 | * Return another reference to | |
708 | * the existing copy-object. | |
709 | */ | |
710 | old_copy->ref_count++; | |
711 | vm_object_unlock(old_copy); | |
712 | vm_object_unlock(src_object); | |
713 | *dst_object = old_copy; | |
714 | *dst_offset = src_offset; | |
715 | *src_needs_copy = FALSE; | |
716 | return; | |
717 | } | |
718 | vm_object_unlock(old_copy); | |
719 | } | |
720 | vm_object_unlock(src_object); | |
721 | ||
722 | /* | |
723 | * If the object has a pager, the pager wants | |
724 | * to see all of the changes. We must make | |
725 | * a copy-object and put the changed pages there. | |
726 | * | |
727 | * The copy-object is always made large enough to | |
728 | * completely shadow the original object, since | |
729 | * it may have several users who want to shadow | |
730 | * the original object at different points. | |
731 | */ | |
732 | ||
733 | new_copy = vm_object_allocate(src_object->size); | |
734 | ||
735 | Retry2: | |
736 | vm_object_lock(src_object); | |
737 | /* | |
738 | * Copy object may have changed while we were unlocked | |
739 | */ | |
740 | old_copy = src_object->copy; | |
741 | if (old_copy != NULL) { | |
742 | /* | |
743 | * Try to get the locks (out of order) | |
744 | */ | |
745 | if (!vm_object_lock_try(old_copy)) { | |
746 | vm_object_unlock(src_object); | |
747 | goto Retry2; | |
748 | } | |
749 | ||
750 | /* | |
751 | * Consistency check | |
752 | */ | |
753 | if (old_copy->shadow != src_object || | |
754 | old_copy->shadow_offset != (vm_offset_t) 0) | |
755 | panic("vm_object_copy: copy/shadow inconsistency"); | |
756 | ||
757 | /* | |
758 | * Make the old copy-object shadow the new one. | |
759 | * It will receive no more pages from the original | |
760 | * object. | |
761 | */ | |
762 | ||
763 | src_object->ref_count--; /* remove ref. from old_copy */ | |
764 | old_copy->shadow = new_copy; | |
765 | new_copy->ref_count++; /* locking not needed - we | |
766 | have the only pointer */ | |
767 | vm_object_unlock(old_copy); /* done with old_copy */ | |
768 | } | |
769 | ||
770 | new_start = (vm_offset_t) 0; /* always shadow original at 0 */ | |
771 | new_end = (vm_offset_t) new_copy->size; /* for the whole object */ | |
772 | ||
773 | /* | |
774 | * Point the new copy at the existing object. | |
775 | */ | |
776 | ||
777 | new_copy->shadow = src_object; | |
778 | new_copy->shadow_offset = new_start; | |
779 | src_object->ref_count++; | |
780 | src_object->copy = new_copy; | |
781 | ||
782 | /* | |
783 | * Mark all the affected pages of the existing object | |
784 | * copy-on-write. | |
785 | */ | |
786 | p = (vm_page_t) queue_first(&src_object->memq); | |
787 | while (!queue_end(&src_object->memq, (queue_entry_t) p)) { | |
788 | if ((new_start <= p->offset) && (p->offset < new_end)) | |
789 | p->copy_on_write = TRUE; | |
790 | p = (vm_page_t) queue_next(&p->listq); | |
791 | } | |
792 | ||
793 | vm_object_unlock(src_object); | |
794 | ||
795 | *dst_object = new_copy; | |
796 | *dst_offset = src_offset - new_start; | |
797 | *src_needs_copy = FALSE; | |
798 | } | |
799 | ||
800 | /* | |
801 | * vm_object_shadow: | |
802 | * | |
803 | * Create a new object which is backed by the | |
804 | * specified existing object range. The source | |
805 | * object reference is deallocated. | |
806 | * | |
807 | * The new object and offset into that object | |
808 | * are returned in the source parameters. | |
809 | */ | |
810 | ||
811 | void vm_object_shadow(object, offset, length) | |
812 | vm_object_t *object; /* IN/OUT */ | |
813 | vm_offset_t *offset; /* IN/OUT */ | |
814 | vm_size_t length; | |
815 | { | |
816 | register vm_object_t source; | |
817 | register vm_object_t result; | |
818 | ||
819 | source = *object; | |
820 | ||
821 | /* | |
822 | * Allocate a new object with the given length | |
823 | */ | |
824 | ||
825 | if ((result = vm_object_allocate(length)) == NULL) | |
826 | panic("vm_object_shadow: no object for shadowing"); | |
827 | ||
828 | /* | |
829 | * The new object shadows the source object, adding | |
830 | * a reference to it. Our caller changes his reference | |
831 | * to point to the new object, removing a reference to | |
832 | * the source object. Net result: no change of reference | |
833 | * count. | |
834 | */ | |
835 | result->shadow = source; | |
836 | ||
837 | /* | |
838 | * Store the offset into the source object, | |
839 | * and fix up the offset into the new object. | |
840 | */ | |
841 | ||
842 | result->shadow_offset = *offset; | |
843 | ||
844 | /* | |
845 | * Return the new things | |
846 | */ | |
847 | ||
848 | *offset = 0; | |
849 | *object = result; | |
850 | } | |
851 | ||
852 | /* | |
853 | * Set the specified object's pager to the specified pager. | |
854 | */ | |
855 | ||
856 | void vm_object_setpager(object, pager, paging_offset, | |
857 | read_only) | |
858 | vm_object_t object; | |
859 | vm_pager_t pager; | |
860 | vm_offset_t paging_offset; | |
861 | boolean_t read_only; | |
862 | { | |
863 | #ifdef lint | |
864 | read_only++; /* No longer used */ | |
865 | #endif lint | |
866 | ||
867 | vm_object_lock(object); /* XXX ? */ | |
868 | object->pager = pager; | |
869 | object->paging_offset = paging_offset; | |
870 | vm_object_unlock(object); /* XXX ? */ | |
871 | } | |
872 | ||
873 | /* | |
874 | * vm_object_hash hashes the pager/id pair. | |
875 | */ | |
876 | ||
877 | #define vm_object_hash(pager) \ | |
878 | (((unsigned)pager)%VM_OBJECT_HASH_COUNT) | |
879 | ||
880 | /* | |
881 | * vm_object_lookup looks in the object cache for an object with the | |
882 | * specified pager and paging id. | |
883 | */ | |
884 | ||
885 | vm_object_t vm_object_lookup(pager) | |
886 | vm_pager_t pager; | |
887 | { | |
888 | register queue_t bucket; | |
889 | register vm_object_hash_entry_t entry; | |
890 | vm_object_t object; | |
891 | ||
892 | bucket = &vm_object_hashtable[vm_object_hash(pager)]; | |
893 | ||
894 | vm_object_cache_lock(); | |
895 | ||
896 | entry = (vm_object_hash_entry_t) queue_first(bucket); | |
897 | while (!queue_end(bucket, (queue_entry_t) entry)) { | |
898 | object = entry->object; | |
899 | if (object->pager == pager) { | |
900 | vm_object_lock(object); | |
901 | if (object->ref_count == 0) { | |
902 | queue_remove(&vm_object_cached_list, object, | |
903 | vm_object_t, cached_list); | |
904 | vm_object_cached--; | |
905 | } | |
906 | object->ref_count++; | |
907 | vm_object_unlock(object); | |
908 | vm_object_cache_unlock(); | |
909 | return(object); | |
910 | } | |
911 | entry = (vm_object_hash_entry_t) queue_next(&entry->hash_links); | |
912 | } | |
913 | ||
914 | vm_object_cache_unlock(); | |
915 | return(NULL); | |
916 | } | |
917 | ||
918 | /* | |
919 | * vm_object_enter enters the specified object/pager/id into | |
920 | * the hash table. | |
921 | */ | |
922 | ||
923 | void vm_object_enter(object, pager) | |
924 | vm_object_t object; | |
925 | vm_pager_t pager; | |
926 | { | |
927 | register queue_t bucket; | |
928 | register vm_object_hash_entry_t entry; | |
929 | ||
930 | /* | |
931 | * We don't cache null objects, and we can't cache | |
932 | * objects with the null pager. | |
933 | */ | |
934 | ||
935 | if (object == NULL) | |
936 | return; | |
937 | if (pager == NULL) | |
938 | return; | |
939 | ||
940 | bucket = &vm_object_hashtable[vm_object_hash(pager)]; | |
941 | entry = (vm_object_hash_entry_t) | |
942 | malloc((u_long)sizeof *entry, M_VMOBJHASH, M_WAITOK); | |
943 | entry->object = object; | |
944 | object->can_persist = TRUE; | |
945 | ||
946 | vm_object_cache_lock(); | |
947 | queue_enter(bucket, entry, vm_object_hash_entry_t, hash_links); | |
948 | vm_object_cache_unlock(); | |
949 | } | |
950 | ||
951 | /* | |
952 | * vm_object_remove: | |
953 | * | |
954 | * Remove the pager from the hash table. | |
955 | * Note: This assumes that the object cache | |
956 | * is locked. XXX this should be fixed | |
957 | * by reorganizing vm_object_deallocate. | |
958 | */ | |
959 | vm_object_remove(pager) | |
960 | register vm_pager_t pager; | |
961 | { | |
962 | register queue_t bucket; | |
963 | register vm_object_hash_entry_t entry; | |
964 | register vm_object_t object; | |
965 | ||
966 | bucket = &vm_object_hashtable[vm_object_hash(pager)]; | |
967 | ||
968 | entry = (vm_object_hash_entry_t) queue_first(bucket); | |
969 | while (!queue_end(bucket, (queue_entry_t) entry)) { | |
970 | object = entry->object; | |
971 | if (object->pager == pager) { | |
972 | queue_remove(bucket, entry, vm_object_hash_entry_t, | |
973 | hash_links); | |
974 | free((caddr_t)entry, M_VMOBJHASH); | |
975 | break; | |
976 | } | |
977 | entry = (vm_object_hash_entry_t) queue_next(&entry->hash_links); | |
978 | } | |
979 | } | |
980 | ||
981 | /* | |
982 | * vm_object_cache_clear removes all objects from the cache. | |
983 | * | |
984 | */ | |
985 | ||
986 | void vm_object_cache_clear() | |
987 | { | |
988 | register vm_object_t object; | |
989 | ||
990 | /* | |
991 | * Remove each object in the cache by scanning down the | |
992 | * list of cached objects. | |
993 | */ | |
994 | vm_object_cache_lock(); | |
995 | while (!queue_empty(&vm_object_cached_list)) { | |
996 | object = (vm_object_t) queue_first(&vm_object_cached_list); | |
997 | vm_object_cache_unlock(); | |
998 | ||
999 | /* | |
1000 | * Note: it is important that we use vm_object_lookup | |
1001 | * to gain a reference, and not vm_object_reference, because | |
1002 | * the logic for removing an object from the cache lies in | |
1003 | * lookup. | |
1004 | */ | |
1005 | if (object != vm_object_lookup(object->pager)) | |
1006 | panic("vm_object_cache_clear: I'm sooo confused."); | |
1007 | pager_cache(object, FALSE); | |
1008 | ||
1009 | vm_object_cache_lock(); | |
1010 | } | |
1011 | vm_object_cache_unlock(); | |
1012 | } | |
1013 | ||
1014 | boolean_t vm_object_collapse_allowed = TRUE; | |
1015 | /* | |
1016 | * vm_object_collapse: | |
1017 | * | |
1018 | * Collapse an object with the object backing it. | |
1019 | * Pages in the backing object are moved into the | |
1020 | * parent, and the backing object is deallocated. | |
1021 | * | |
1022 | * Requires that the object be locked and the page | |
1023 | * queues be unlocked. | |
1024 | * | |
1025 | */ | |
1026 | void vm_object_collapse(object) | |
1027 | register vm_object_t object; | |
1028 | ||
1029 | { | |
1030 | register vm_object_t backing_object; | |
1031 | register vm_offset_t backing_offset; | |
1032 | register vm_size_t size; | |
1033 | register vm_offset_t new_offset; | |
1034 | register vm_page_t p, pp; | |
1035 | ||
1036 | if (!vm_object_collapse_allowed) | |
1037 | return; | |
1038 | ||
1039 | while (TRUE) { | |
1040 | /* | |
1041 | * Verify that the conditions are right for collapse: | |
1042 | * | |
1043 | * The object exists and no pages in it are currently | |
1044 | * being paged out (or have ever been paged out). | |
1045 | */ | |
1046 | if (object == NULL || | |
1047 | object->paging_in_progress != 0 || | |
1048 | object->pager != NULL) | |
1049 | return; | |
1050 | ||
1051 | /* | |
1052 | * There is a backing object, and | |
1053 | */ | |
1054 | ||
1055 | if ((backing_object = object->shadow) == NULL) | |
1056 | return; | |
1057 | ||
1058 | vm_object_lock(backing_object); | |
1059 | /* | |
1060 | * ... | |
1061 | * The backing object is not read_only, | |
1062 | * and no pages in the backing object are | |
1063 | * currently being paged out. | |
1064 | * The backing object is internal. | |
1065 | */ | |
1066 | ||
1067 | if (!backing_object->internal || | |
1068 | backing_object->paging_in_progress != 0) { | |
1069 | vm_object_unlock(backing_object); | |
1070 | return; | |
1071 | } | |
1072 | ||
1073 | /* | |
1074 | * The backing object can't be a copy-object: | |
1075 | * the shadow_offset for the copy-object must stay | |
1076 | * as 0. Furthermore (for the 'we have all the | |
1077 | * pages' case), if we bypass backing_object and | |
1078 | * just shadow the next object in the chain, old | |
1079 | * pages from that object would then have to be copied | |
1080 | * BOTH into the (former) backing_object and into the | |
1081 | * parent object. | |
1082 | */ | |
1083 | if (backing_object->shadow != NULL && | |
1084 | backing_object->shadow->copy != NULL) { | |
1085 | vm_object_unlock(backing_object); | |
1086 | return; | |
1087 | } | |
1088 | ||
1089 | /* | |
1090 | * We know that we can either collapse the backing | |
1091 | * object (if the parent is the only reference to | |
1092 | * it) or (perhaps) remove the parent's reference | |
1093 | * to it. | |
1094 | */ | |
1095 | ||
1096 | backing_offset = object->shadow_offset; | |
1097 | size = object->size; | |
1098 | ||
1099 | /* | |
1100 | * If there is exactly one reference to the backing | |
1101 | * object, we can collapse it into the parent. | |
1102 | */ | |
1103 | ||
1104 | if (backing_object->ref_count == 1) { | |
1105 | ||
1106 | /* | |
1107 | * We can collapse the backing object. | |
1108 | * | |
1109 | * Move all in-memory pages from backing_object | |
1110 | * to the parent. Pages that have been paged out | |
1111 | * will be overwritten by any of the parent's | |
1112 | * pages that shadow them. | |
1113 | */ | |
1114 | ||
1115 | while (!queue_empty(&backing_object->memq)) { | |
1116 | ||
1117 | p = (vm_page_t) | |
1118 | queue_first(&backing_object->memq); | |
1119 | ||
1120 | new_offset = (p->offset - backing_offset); | |
1121 | ||
1122 | /* | |
1123 | * If the parent has a page here, or if | |
1124 | * this page falls outside the parent, | |
1125 | * dispose of it. | |
1126 | * | |
1127 | * Otherwise, move it as planned. | |
1128 | */ | |
1129 | ||
1130 | if (p->offset < backing_offset || | |
1131 | new_offset >= size) { | |
1132 | vm_page_lock_queues(); | |
1133 | vm_page_free(p); | |
1134 | vm_page_unlock_queues(); | |
1135 | } else { | |
1136 | pp = vm_page_lookup(object, new_offset); | |
1137 | if (pp != NULL && !pp->fake) { | |
1138 | vm_page_lock_queues(); | |
1139 | vm_page_free(p); | |
1140 | vm_page_unlock_queues(); | |
1141 | } | |
1142 | else { | |
1143 | if (pp) { | |
1144 | /* may be someone waiting for it */ | |
1145 | PAGE_WAKEUP(pp); | |
1146 | vm_page_lock_queues(); | |
1147 | vm_page_free(pp); | |
1148 | vm_page_unlock_queues(); | |
1149 | } | |
1150 | vm_page_rename(p, object, new_offset); | |
1151 | } | |
1152 | } | |
1153 | } | |
1154 | ||
1155 | /* | |
1156 | * Move the pager from backing_object to object. | |
1157 | * | |
1158 | * XXX We're only using part of the paging space | |
1159 | * for keeps now... we ought to discard the | |
1160 | * unused portion. | |
1161 | */ | |
1162 | ||
1163 | object->pager = backing_object->pager; | |
1164 | object->paging_offset += backing_offset; | |
1165 | ||
1166 | backing_object->pager = NULL; | |
1167 | ||
1168 | /* | |
1169 | * Object now shadows whatever backing_object did. | |
1170 | * Note that the reference to backing_object->shadow | |
1171 | * moves from within backing_object to within object. | |
1172 | */ | |
1173 | ||
1174 | object->shadow = backing_object->shadow; | |
1175 | object->shadow_offset += backing_object->shadow_offset; | |
1176 | if (object->shadow != NULL && | |
1177 | object->shadow->copy != NULL) { | |
1178 | panic("vm_object_collapse: we collapsed a copy-object!"); | |
1179 | } | |
1180 | /* | |
1181 | * Discard backing_object. | |
1182 | * | |
1183 | * Since the backing object has no pages, no | |
1184 | * pager left, and no object references within it, | |
1185 | * all that is necessary is to dispose of it. | |
1186 | */ | |
1187 | ||
1188 | vm_object_unlock(backing_object); | |
1189 | ||
1190 | simple_lock(&vm_object_list_lock); | |
1191 | queue_remove(&vm_object_list, backing_object, | |
1192 | vm_object_t, object_list); | |
1193 | vm_object_count--; | |
1194 | simple_unlock(&vm_object_list_lock); | |
1195 | ||
1196 | free((caddr_t)backing_object, M_VMOBJ); | |
1197 | ||
1198 | object_collapses++; | |
1199 | } | |
1200 | else { | |
1201 | /* | |
1202 | * If all of the pages in the backing object are | |
1203 | * shadowed by the parent object, the parent | |
1204 | * object no longer has to shadow the backing | |
1205 | * object; it can shadow the next one in the | |
1206 | * chain. | |
1207 | * | |
1208 | * The backing object must not be paged out - we'd | |
1209 | * have to check all of the paged-out pages, as | |
1210 | * well. | |
1211 | */ | |
1212 | ||
1213 | if (backing_object->pager != NULL) { | |
1214 | vm_object_unlock(backing_object); | |
1215 | return; | |
1216 | } | |
1217 | ||
1218 | /* | |
1219 | * Should have a check for a 'small' number | |
1220 | * of pages here. | |
1221 | */ | |
1222 | ||
1223 | p = (vm_page_t) queue_first(&backing_object->memq); | |
1224 | while (!queue_end(&backing_object->memq, | |
1225 | (queue_entry_t) p)) { | |
1226 | ||
1227 | new_offset = (p->offset - backing_offset); | |
1228 | ||
1229 | /* | |
1230 | * If the parent has a page here, or if | |
1231 | * this page falls outside the parent, | |
1232 | * keep going. | |
1233 | * | |
1234 | * Otherwise, the backing_object must be | |
1235 | * left in the chain. | |
1236 | */ | |
1237 | ||
1238 | if (p->offset >= backing_offset && | |
1239 | new_offset <= size && | |
1240 | ((pp = vm_page_lookup(object, new_offset)) | |
1241 | == NULL || | |
1242 | pp->fake)) { | |
1243 | /* | |
1244 | * Page still needed. | |
1245 | * Can't go any further. | |
1246 | */ | |
1247 | vm_object_unlock(backing_object); | |
1248 | return; | |
1249 | } | |
1250 | p = (vm_page_t) queue_next(&p->listq); | |
1251 | } | |
1252 | ||
1253 | /* | |
1254 | * Make the parent shadow the next object | |
1255 | * in the chain. Deallocating backing_object | |
1256 | * will not remove it, since its reference | |
1257 | * count is at least 2. | |
1258 | */ | |
1259 | ||
1260 | vm_object_reference(object->shadow = backing_object->shadow); | |
1261 | object->shadow_offset += backing_object->shadow_offset; | |
1262 | ||
1263 | /* Drop the reference count on backing_object. | |
1264 | * Since its ref_count was at least 2, it | |
1265 | * will not vanish; so we don't need to call | |
1266 | * vm_object_deallocate. | |
1267 | */ | |
1268 | backing_object->ref_count--; | |
1269 | vm_object_unlock(backing_object); | |
1270 | ||
1271 | object_bypasses ++; | |
1272 | ||
1273 | } | |
1274 | ||
1275 | /* | |
1276 | * Try again with this object's new backing object. | |
1277 | */ | |
1278 | } | |
1279 | } | |
1280 | ||
1281 | /* | |
1282 | * vm_object_page_remove: [internal] | |
1283 | * | |
1284 | * Removes all physical pages in the specified | |
1285 | * object range from the object's list of pages. | |
1286 | * | |
1287 | * The object must be locked. | |
1288 | */ | |
1289 | void vm_object_page_remove(object, start, end) | |
1290 | register vm_object_t object; | |
1291 | register vm_offset_t start; | |
1292 | register vm_offset_t end; | |
1293 | { | |
1294 | register vm_page_t p, next; | |
1295 | ||
1296 | if (object == NULL) | |
1297 | return; | |
1298 | ||
1299 | p = (vm_page_t) queue_first(&object->memq); | |
1300 | while (!queue_end(&object->memq, (queue_entry_t) p)) { | |
1301 | next = (vm_page_t) queue_next(&p->listq); | |
1302 | if ((start <= p->offset) && (p->offset < end)) { | |
1303 | pmap_page_protect(VM_PAGE_TO_PHYS(p), VM_PROT_NONE); | |
1304 | vm_page_lock_queues(); | |
1305 | vm_page_free(p); | |
1306 | vm_page_unlock_queues(); | |
1307 | } | |
1308 | p = next; | |
1309 | } | |
1310 | } | |
1311 | ||
1312 | /* | |
1313 | * Routine: vm_object_coalesce | |
1314 | * Function: Coalesces two objects backing up adjoining | |
1315 | * regions of memory into a single object. | |
1316 | * | |
1317 | * returns TRUE if objects were combined. | |
1318 | * | |
1319 | * NOTE: Only works at the moment if the second object is NULL - | |
1320 | * if it's not, which object do we lock first? | |
1321 | * | |
1322 | * Parameters: | |
1323 | * prev_object First object to coalesce | |
1324 | * prev_offset Offset into prev_object | |
1325 | * next_object Second object into coalesce | |
1326 | * next_offset Offset into next_object | |
1327 | * | |
1328 | * prev_size Size of reference to prev_object | |
1329 | * next_size Size of reference to next_object | |
1330 | * | |
1331 | * Conditions: | |
1332 | * The object must *not* be locked. | |
1333 | */ | |
1334 | boolean_t vm_object_coalesce(prev_object, next_object, | |
1335 | prev_offset, next_offset, | |
1336 | prev_size, next_size) | |
1337 | ||
1338 | register vm_object_t prev_object; | |
1339 | vm_object_t next_object; | |
1340 | vm_offset_t prev_offset, next_offset; | |
1341 | vm_size_t prev_size, next_size; | |
1342 | { | |
1343 | vm_size_t newsize; | |
1344 | ||
1345 | #ifdef lint | |
1346 | next_offset++; | |
1347 | #endif lint | |
1348 | ||
1349 | if (next_object != NULL) { | |
1350 | return(FALSE); | |
1351 | } | |
1352 | ||
1353 | if (prev_object == NULL) { | |
1354 | return(TRUE); | |
1355 | } | |
1356 | ||
1357 | vm_object_lock(prev_object); | |
1358 | ||
1359 | /* | |
1360 | * Try to collapse the object first | |
1361 | */ | |
1362 | vm_object_collapse(prev_object); | |
1363 | ||
1364 | /* | |
1365 | * Can't coalesce if: | |
1366 | * . more than one reference | |
1367 | * . paged out | |
1368 | * . shadows another object | |
1369 | * . has a copy elsewhere | |
1370 | * (any of which mean that the pages not mapped to | |
1371 | * prev_entry may be in use anyway) | |
1372 | */ | |
1373 | ||
1374 | if (prev_object->ref_count > 1 || | |
1375 | prev_object->pager != NULL || | |
1376 | prev_object->shadow != NULL || | |
1377 | prev_object->copy != NULL) { | |
1378 | vm_object_unlock(prev_object); | |
1379 | return(FALSE); | |
1380 | } | |
1381 | ||
1382 | /* | |
1383 | * Remove any pages that may still be in the object from | |
1384 | * a previous deallocation. | |
1385 | */ | |
1386 | ||
1387 | vm_object_page_remove(prev_object, | |
1388 | prev_offset + prev_size, | |
1389 | prev_offset + prev_size + next_size); | |
1390 | ||
1391 | /* | |
1392 | * Extend the object if necessary. | |
1393 | */ | |
1394 | newsize = prev_offset + prev_size + next_size; | |
1395 | if (newsize > prev_object->size) | |
1396 | prev_object->size = newsize; | |
1397 | ||
1398 | vm_object_unlock(prev_object); | |
1399 | return(TRUE); | |
1400 | } | |
1401 | ||
1402 | /* | |
1403 | * vm_object_print: [ debug ] | |
1404 | */ | |
1405 | void vm_object_print(object, full) | |
1406 | vm_object_t object; | |
1407 | boolean_t full; | |
1408 | { | |
1409 | register vm_page_t p; | |
1410 | extern indent; | |
1411 | ||
1412 | register int count; | |
1413 | ||
1414 | if (object == NULL) | |
1415 | return; | |
1416 | ||
1417 | iprintf("Object 0x%x: size=0x%x, res=%d, ref=%d, ", | |
1418 | (int) object, (int) object->size, | |
1419 | object->resident_page_count, object->ref_count); | |
1420 | printf("pager=0x%x+0x%x, shadow=(0x%x)+0x%x\n", | |
1421 | (int) object->pager, (int) object->paging_offset, | |
1422 | (int) object->shadow, (int) object->shadow_offset); | |
1423 | printf("cache: next=0x%x, prev=0x%x\n", | |
1424 | object->cached_list.next, object->cached_list.prev); | |
1425 | ||
1426 | if (!full) | |
1427 | return; | |
1428 | ||
1429 | indent += 2; | |
1430 | count = 0; | |
1431 | p = (vm_page_t) queue_first(&object->memq); | |
1432 | while (!queue_end(&object->memq, (queue_entry_t) p)) { | |
1433 | if (count == 0) | |
1434 | iprintf("memory:="); | |
1435 | else if (count == 6) { | |
1436 | printf("\n"); | |
1437 | iprintf(" ..."); | |
1438 | count = 0; | |
1439 | } else | |
1440 | printf(","); | |
1441 | count++; | |
1442 | ||
1443 | printf("(off=0x%x,page=0x%x)", p->offset, VM_PAGE_TO_PHYS(p)); | |
1444 | p = (vm_page_t) queue_next(&p->listq); | |
1445 | } | |
1446 | if (count != 0) | |
1447 | printf("\n"); | |
1448 | indent -= 2; | |
1449 | } |