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175f072e | 1 | /* |
175f072e KM |
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 | * | |
0e24ad83 | 8 | * %sccs.include.redist.c% |
175f072e | 9 | * |
ae1e5b95 | 10 | * @(#)vm_object.c 7.4 (Berkeley) %G% |
0e24ad83 KM |
11 | * |
12 | * | |
13 | * Copyright (c) 1987, 1990 Carnegie-Mellon University. | |
14 | * All rights reserved. | |
15 | * | |
16 | * Authors: Avadis Tevanian, Jr., Michael Wayne Young | |
17 | * | |
18 | * Permission to use, copy, modify and distribute this software and | |
19 | * its documentation is hereby granted, provided that both the copyright | |
20 | * notice and this permission notice appear in all copies of the | |
21 | * software, derivative works or modified versions, and any portions | |
22 | * thereof, and that both notices appear in supporting documentation. | |
23 | * | |
24 | * CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS" | |
25 | * CONDITION. CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND | |
26 | * FOR ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE. | |
27 | * | |
28 | * Carnegie Mellon requests users of this software to return to | |
29 | * | |
30 | * Software Distribution Coordinator or Software.Distribution@CS.CMU.EDU | |
31 | * School of Computer Science | |
32 | * Carnegie Mellon University | |
33 | * Pittsburgh PA 15213-3890 | |
34 | * | |
35 | * any improvements or extensions that they make and grant Carnegie the | |
36 | * rights to redistribute these changes. | |
175f072e KM |
37 | */ |
38 | ||
39 | /* | |
40 | * Virtual memory object module. | |
41 | */ | |
42 | ||
43 | #include "param.h" | |
44 | #include "malloc.h" | |
ffe0d082 MK |
45 | |
46 | #include "vm.h" | |
47 | #include "vm_page.h" | |
175f072e KM |
48 | |
49 | /* | |
50 | * Virtual memory objects maintain the actual data | |
51 | * associated with allocated virtual memory. A given | |
52 | * page of memory exists within exactly one object. | |
53 | * | |
54 | * An object is only deallocated when all "references" | |
55 | * are given up. Only one "reference" to a given | |
56 | * region of an object should be writeable. | |
57 | * | |
58 | * Associated with each object is a list of all resident | |
59 | * memory pages belonging to that object; this list is | |
60 | * maintained by the "vm_page" module, and locked by the object's | |
61 | * lock. | |
62 | * | |
63 | * Each object also records a "pager" routine which is | |
64 | * used to retrieve (and store) pages to the proper backing | |
65 | * storage. In addition, objects may be backed by other | |
66 | * objects from which they were virtual-copied. | |
67 | * | |
68 | * The only items within the object structure which are | |
69 | * modified after time of creation are: | |
70 | * reference count locked by object's lock | |
71 | * pager routine locked by object's lock | |
72 | * | |
73 | */ | |
74 | ||
75 | struct vm_object kernel_object_store; | |
76 | struct vm_object kmem_object_store; | |
77 | ||
78 | #define VM_OBJECT_HASH_COUNT 157 | |
79 | ||
80 | int vm_cache_max = 100; /* can patch if necessary */ | |
81 | queue_head_t vm_object_hashtable[VM_OBJECT_HASH_COUNT]; | |
82 | ||
83 | long object_collapses = 0; | |
84 | long object_bypasses = 0; | |
85 | ||
86 | /* | |
87 | * vm_object_init: | |
88 | * | |
89 | * Initialize the VM objects module. | |
90 | */ | |
91 | void vm_object_init() | |
92 | { | |
93 | register int i; | |
94 | ||
95 | queue_init(&vm_object_cached_list); | |
96 | queue_init(&vm_object_list); | |
97 | vm_object_count = 0; | |
98 | simple_lock_init(&vm_cache_lock); | |
99 | simple_lock_init(&vm_object_list_lock); | |
100 | ||
101 | for (i = 0; i < VM_OBJECT_HASH_COUNT; i++) | |
102 | queue_init(&vm_object_hashtable[i]); | |
103 | ||
104 | kernel_object = &kernel_object_store; | |
105 | _vm_object_allocate(VM_MAX_KERNEL_ADDRESS - VM_MIN_KERNEL_ADDRESS, | |
106 | kernel_object); | |
107 | ||
108 | kmem_object = &kmem_object_store; | |
109 | _vm_object_allocate(VM_KMEM_SIZE + VM_MBUF_SIZE, kmem_object); | |
110 | } | |
111 | ||
112 | /* | |
113 | * vm_object_allocate: | |
114 | * | |
115 | * Returns a new object with the given size. | |
116 | */ | |
117 | ||
118 | vm_object_t vm_object_allocate(size) | |
119 | vm_size_t size; | |
120 | { | |
121 | register vm_object_t result; | |
122 | ||
123 | result = (vm_object_t) | |
124 | malloc((u_long)sizeof *result, M_VMOBJ, M_WAITOK); | |
125 | ||
126 | _vm_object_allocate(size, result); | |
127 | ||
128 | return(result); | |
129 | } | |
130 | ||
131 | _vm_object_allocate(size, object) | |
132 | vm_size_t size; | |
133 | register vm_object_t object; | |
134 | { | |
135 | queue_init(&object->memq); | |
136 | vm_object_lock_init(object); | |
137 | object->ref_count = 1; | |
138 | object->resident_page_count = 0; | |
139 | object->size = size; | |
140 | object->can_persist = FALSE; | |
141 | object->paging_in_progress = 0; | |
ffe0d082 | 142 | object->copy = NULL; |
175f072e KM |
143 | |
144 | /* | |
145 | * Object starts out read-write, with no pager. | |
146 | */ | |
147 | ||
ffe0d082 | 148 | object->pager = NULL; |
175f072e KM |
149 | object->pager_ready = FALSE; |
150 | object->internal = TRUE; /* vm_allocate_with_pager will reset */ | |
151 | object->paging_offset = 0; | |
ffe0d082 | 152 | object->shadow = NULL; |
175f072e KM |
153 | object->shadow_offset = (vm_offset_t) 0; |
154 | ||
155 | simple_lock(&vm_object_list_lock); | |
156 | queue_enter(&vm_object_list, object, vm_object_t, object_list); | |
157 | vm_object_count++; | |
158 | simple_unlock(&vm_object_list_lock); | |
159 | } | |
160 | ||
161 | /* | |
162 | * vm_object_reference: | |
163 | * | |
164 | * Gets another reference to the given object. | |
165 | */ | |
166 | void vm_object_reference(object) | |
167 | register vm_object_t object; | |
168 | { | |
ffe0d082 | 169 | if (object == NULL) |
175f072e KM |
170 | return; |
171 | ||
172 | vm_object_lock(object); | |
173 | object->ref_count++; | |
174 | vm_object_unlock(object); | |
175 | } | |
176 | ||
177 | /* | |
178 | * vm_object_deallocate: | |
179 | * | |
180 | * Release a reference to the specified object, | |
181 | * gained either through a vm_object_allocate | |
182 | * or a vm_object_reference call. When all references | |
183 | * are gone, storage associated with this object | |
184 | * may be relinquished. | |
185 | * | |
186 | * No object may be locked. | |
187 | */ | |
188 | void vm_object_deallocate(object) | |
189 | register vm_object_t object; | |
190 | { | |
191 | vm_object_t temp; | |
192 | ||
ffe0d082 | 193 | while (object != NULL) { |
175f072e KM |
194 | |
195 | /* | |
196 | * The cache holds a reference (uncounted) to | |
197 | * the object; we must lock it before removing | |
198 | * the object. | |
199 | */ | |
200 | ||
201 | vm_object_cache_lock(); | |
202 | ||
203 | /* | |
204 | * Lose the reference | |
205 | */ | |
206 | vm_object_lock(object); | |
207 | if (--(object->ref_count) != 0) { | |
208 | ||
209 | /* | |
210 | * If there are still references, then | |
211 | * we are done. | |
212 | */ | |
213 | vm_object_unlock(object); | |
214 | vm_object_cache_unlock(); | |
215 | return; | |
216 | } | |
217 | ||
218 | /* | |
219 | * See if this object can persist. If so, enter | |
220 | * it in the cache, then deactivate all of its | |
221 | * pages. | |
222 | */ | |
223 | ||
224 | if (object->can_persist) { | |
225 | ||
226 | queue_enter(&vm_object_cached_list, object, | |
227 | vm_object_t, cached_list); | |
228 | vm_object_cached++; | |
229 | vm_object_cache_unlock(); | |
230 | ||
231 | vm_object_deactivate_pages(object); | |
232 | vm_object_unlock(object); | |
233 | ||
234 | vm_object_cache_trim(); | |
235 | return; | |
236 | } | |
237 | ||
238 | /* | |
239 | * Make sure no one can look us up now. | |
240 | */ | |
241 | vm_object_remove(object->pager); | |
242 | vm_object_cache_unlock(); | |
243 | ||
244 | temp = object->shadow; | |
245 | vm_object_terminate(object); | |
246 | /* unlocks and deallocates object */ | |
247 | object = temp; | |
248 | } | |
249 | } | |
250 | ||
251 | ||
252 | /* | |
253 | * vm_object_terminate actually destroys the specified object, freeing | |
254 | * up all previously used resources. | |
255 | * | |
256 | * The object must be locked. | |
257 | */ | |
258 | void vm_object_terminate(object) | |
259 | register vm_object_t object; | |
260 | { | |
261 | register vm_page_t p; | |
262 | vm_object_t shadow_object; | |
263 | ||
264 | /* | |
265 | * Detach the object from its shadow if we are the shadow's | |
266 | * copy. | |
267 | */ | |
ffe0d082 | 268 | if ((shadow_object = object->shadow) != NULL) { |
175f072e KM |
269 | vm_object_lock(shadow_object); |
270 | if (shadow_object->copy == object) | |
ffe0d082 | 271 | shadow_object->copy = NULL; |
175f072e | 272 | #if 0 |
ffe0d082 | 273 | else if (shadow_object->copy != NULL) |
175f072e KM |
274 | panic("vm_object_terminate: copy/shadow inconsistency"); |
275 | #endif | |
276 | vm_object_unlock(shadow_object); | |
277 | } | |
278 | ||
279 | /* | |
280 | * Wait until the pageout daemon is through | |
281 | * with the object. | |
282 | */ | |
283 | ||
284 | while (object->paging_in_progress != 0) { | |
285 | vm_object_sleep(object, object, FALSE); | |
286 | vm_object_lock(object); | |
287 | } | |
288 | ||
289 | ||
290 | /* | |
291 | * While the paging system is locked, | |
292 | * pull the object's pages off the active | |
293 | * and inactive queues. This keeps the | |
294 | * pageout daemon from playing with them | |
295 | * during vm_pager_deallocate. | |
296 | * | |
297 | * We can't free the pages yet, because the | |
298 | * object's pager may have to write them out | |
299 | * before deallocating the paging space. | |
300 | */ | |
301 | ||
302 | p = (vm_page_t) queue_first(&object->memq); | |
303 | while (!queue_end(&object->memq, (queue_entry_t) p)) { | |
304 | VM_PAGE_CHECK(p); | |
305 | ||
306 | vm_page_lock_queues(); | |
307 | if (p->active) { | |
308 | queue_remove(&vm_page_queue_active, p, vm_page_t, | |
309 | pageq); | |
310 | p->active = FALSE; | |
311 | vm_page_active_count--; | |
312 | } | |
313 | ||
314 | if (p->inactive) { | |
315 | queue_remove(&vm_page_queue_inactive, p, vm_page_t, | |
316 | pageq); | |
317 | p->inactive = FALSE; | |
318 | vm_page_inactive_count--; | |
319 | } | |
320 | vm_page_unlock_queues(); | |
321 | p = (vm_page_t) queue_next(&p->listq); | |
322 | } | |
323 | ||
324 | vm_object_unlock(object); | |
325 | ||
326 | if (object->paging_in_progress != 0) | |
327 | panic("vm_object_deallocate: pageout in progress"); | |
328 | ||
329 | /* | |
330 | * Clean and free the pages, as appropriate. | |
331 | * All references to the object are gone, | |
332 | * so we don't need to lock it. | |
333 | */ | |
334 | ||
335 | if (!object->internal) { | |
336 | vm_object_lock(object); | |
337 | vm_object_page_clean(object, 0, 0); | |
338 | vm_object_unlock(object); | |
339 | } | |
340 | while (!queue_empty(&object->memq)) { | |
341 | p = (vm_page_t) queue_first(&object->memq); | |
342 | ||
343 | VM_PAGE_CHECK(p); | |
344 | ||
345 | vm_page_lock_queues(); | |
346 | vm_page_free(p); | |
347 | vm_page_unlock_queues(); | |
348 | } | |
349 | ||
350 | /* | |
351 | * Let the pager know object is dead. | |
352 | */ | |
353 | ||
ffe0d082 | 354 | if (object->pager != NULL) |
175f072e KM |
355 | vm_pager_deallocate(object->pager); |
356 | ||
357 | ||
358 | simple_lock(&vm_object_list_lock); | |
359 | queue_remove(&vm_object_list, object, vm_object_t, object_list); | |
360 | vm_object_count--; | |
361 | simple_unlock(&vm_object_list_lock); | |
362 | ||
363 | /* | |
364 | * Free the space for the object. | |
365 | */ | |
366 | ||
367 | free((caddr_t)object, M_VMOBJ); | |
368 | } | |
369 | ||
370 | /* | |
371 | * vm_object_page_clean | |
372 | * | |
373 | * Clean all dirty pages in the specified range of object. | |
374 | * Leaves page on whatever queue it is currently on. | |
375 | * | |
376 | * Odd semantics: if start == end, we clean everything. | |
377 | * | |
378 | * The object must be locked. | |
379 | */ | |
380 | vm_object_page_clean(object, start, end) | |
381 | register vm_object_t object; | |
382 | register vm_offset_t start; | |
383 | register vm_offset_t end; | |
384 | { | |
385 | register vm_page_t p; | |
386 | ||
ffe0d082 | 387 | if (object->pager == NULL) |
175f072e KM |
388 | return; |
389 | ||
390 | again: | |
391 | p = (vm_page_t) queue_first(&object->memq); | |
392 | while (!queue_end(&object->memq, (queue_entry_t) p)) { | |
393 | if (start == end || | |
394 | p->offset >= start && p->offset < end) { | |
395 | if (p->clean && pmap_is_modified(VM_PAGE_TO_PHYS(p))) | |
396 | p->clean = FALSE; | |
ae1e5b95 | 397 | pmap_page_protect(VM_PAGE_TO_PHYS(p), VM_PROT_NONE); |
175f072e KM |
398 | if (!p->clean) { |
399 | p->busy = TRUE; | |
400 | object->paging_in_progress++; | |
401 | vm_object_unlock(object); | |
402 | (void) vm_pager_put(object->pager, p, TRUE); | |
403 | vm_object_lock(object); | |
404 | object->paging_in_progress--; | |
405 | p->busy = FALSE; | |
406 | PAGE_WAKEUP(p); | |
407 | goto again; | |
408 | } | |
409 | } | |
410 | p = (vm_page_t) queue_next(&p->listq); | |
411 | } | |
412 | } | |
413 | ||
414 | /* | |
415 | * vm_object_deactivate_pages | |
416 | * | |
417 | * Deactivate all pages in the specified object. (Keep its pages | |
418 | * in memory even though it is no longer referenced.) | |
419 | * | |
420 | * The object must be locked. | |
421 | */ | |
422 | vm_object_deactivate_pages(object) | |
423 | register vm_object_t object; | |
424 | { | |
425 | register vm_page_t p, next; | |
426 | ||
427 | p = (vm_page_t) queue_first(&object->memq); | |
428 | while (!queue_end(&object->memq, (queue_entry_t) p)) { | |
429 | next = (vm_page_t) queue_next(&p->listq); | |
430 | vm_page_lock_queues(); | |
431 | vm_page_deactivate(p); | |
432 | vm_page_unlock_queues(); | |
433 | p = next; | |
434 | } | |
435 | } | |
436 | ||
437 | /* | |
438 | * Trim the object cache to size. | |
439 | */ | |
440 | vm_object_cache_trim() | |
441 | { | |
442 | register vm_object_t object; | |
443 | ||
444 | vm_object_cache_lock(); | |
445 | while (vm_object_cached > vm_cache_max) { | |
446 | object = (vm_object_t) queue_first(&vm_object_cached_list); | |
447 | vm_object_cache_unlock(); | |
448 | ||
449 | if (object != vm_object_lookup(object->pager)) | |
450 | panic("vm_object_deactivate: I'm sooo confused."); | |
451 | ||
452 | pager_cache(object, FALSE); | |
453 | ||
454 | vm_object_cache_lock(); | |
455 | } | |
456 | vm_object_cache_unlock(); | |
457 | } | |
458 | ||
459 | ||
460 | /* | |
461 | * vm_object_shutdown() | |
462 | * | |
463 | * Shut down the object system. Unfortunately, while we | |
464 | * may be trying to do this, init is happily waiting for | |
465 | * processes to exit, and therefore will be causing some objects | |
466 | * to be deallocated. To handle this, we gain a fake reference | |
467 | * to all objects we release paging areas for. This will prevent | |
468 | * a duplicate deallocation. This routine is probably full of | |
469 | * race conditions! | |
470 | */ | |
471 | ||
472 | void vm_object_shutdown() | |
473 | { | |
474 | register vm_object_t object; | |
475 | ||
476 | /* | |
477 | * Clean up the object cache *before* we screw up the reference | |
478 | * counts on all of the objects. | |
479 | */ | |
480 | ||
481 | vm_object_cache_clear(); | |
482 | ||
483 | printf("free paging spaces: "); | |
484 | ||
485 | /* | |
486 | * First we gain a reference to each object so that | |
487 | * no one else will deallocate them. | |
488 | */ | |
489 | ||
490 | simple_lock(&vm_object_list_lock); | |
491 | object = (vm_object_t) queue_first(&vm_object_list); | |
492 | while (!queue_end(&vm_object_list, (queue_entry_t) object)) { | |
493 | vm_object_reference(object); | |
494 | object = (vm_object_t) queue_next(&object->object_list); | |
495 | } | |
496 | simple_unlock(&vm_object_list_lock); | |
497 | ||
498 | /* | |
499 | * Now we deallocate all the paging areas. We don't need | |
500 | * to lock anything because we've reduced to a single | |
501 | * processor while shutting down. This also assumes that | |
502 | * no new objects are being created. | |
503 | */ | |
504 | ||
505 | object = (vm_object_t) queue_first(&vm_object_list); | |
506 | while (!queue_end(&vm_object_list, (queue_entry_t) object)) { | |
ffe0d082 | 507 | if (object->pager != NULL) |
175f072e KM |
508 | vm_pager_deallocate(object->pager); |
509 | object = (vm_object_t) queue_next(&object->object_list); | |
510 | printf("."); | |
511 | } | |
512 | printf("done.\n"); | |
513 | } | |
514 | ||
515 | /* | |
516 | * vm_object_pmap_copy: | |
517 | * | |
518 | * Makes all physical pages in the specified | |
519 | * object range copy-on-write. No writeable | |
520 | * references to these pages should remain. | |
521 | * | |
522 | * The object must *not* be locked. | |
523 | */ | |
524 | void vm_object_pmap_copy(object, start, end) | |
525 | register vm_object_t object; | |
526 | register vm_offset_t start; | |
527 | register vm_offset_t end; | |
528 | { | |
529 | register vm_page_t p; | |
530 | ||
ffe0d082 | 531 | if (object == NULL) |
175f072e KM |
532 | return; |
533 | ||
534 | vm_object_lock(object); | |
535 | p = (vm_page_t) queue_first(&object->memq); | |
536 | while (!queue_end(&object->memq, (queue_entry_t) p)) { | |
537 | if ((start <= p->offset) && (p->offset < end)) { | |
ae1e5b95 MH |
538 | pmap_page_protect(VM_PAGE_TO_PHYS(p), VM_PROT_READ); |
539 | p->copy_on_write = TRUE; | |
175f072e KM |
540 | } |
541 | p = (vm_page_t) queue_next(&p->listq); | |
542 | } | |
543 | vm_object_unlock(object); | |
544 | } | |
545 | ||
546 | /* | |
547 | * vm_object_pmap_remove: | |
548 | * | |
549 | * Removes all physical pages in the specified | |
550 | * object range from all physical maps. | |
551 | * | |
552 | * The object must *not* be locked. | |
553 | */ | |
554 | void vm_object_pmap_remove(object, start, end) | |
555 | register vm_object_t object; | |
556 | register vm_offset_t start; | |
557 | register vm_offset_t end; | |
558 | { | |
559 | register vm_page_t p; | |
560 | ||
ffe0d082 | 561 | if (object == NULL) |
175f072e KM |
562 | return; |
563 | ||
564 | vm_object_lock(object); | |
565 | p = (vm_page_t) queue_first(&object->memq); | |
566 | while (!queue_end(&object->memq, (queue_entry_t) p)) { | |
ae1e5b95 MH |
567 | if ((start <= p->offset) && (p->offset < end)) |
568 | pmap_page_protect(VM_PAGE_TO_PHYS(p), VM_PROT_NONE); | |
175f072e KM |
569 | p = (vm_page_t) queue_next(&p->listq); |
570 | } | |
571 | vm_object_unlock(object); | |
572 | } | |
573 | ||
574 | /* | |
575 | * vm_object_copy: | |
576 | * | |
577 | * Create a new object which is a copy of an existing | |
578 | * object, and mark all of the pages in the existing | |
579 | * object 'copy-on-write'. The new object has one reference. | |
580 | * Returns the new object. | |
581 | * | |
582 | * May defer the copy until later if the object is not backed | |
583 | * up by a non-default pager. | |
584 | */ | |
585 | void vm_object_copy(src_object, src_offset, size, | |
586 | dst_object, dst_offset, src_needs_copy) | |
587 | register vm_object_t src_object; | |
588 | vm_offset_t src_offset; | |
589 | vm_size_t size; | |
590 | vm_object_t *dst_object; /* OUT */ | |
591 | vm_offset_t *dst_offset; /* OUT */ | |
592 | boolean_t *src_needs_copy; /* OUT */ | |
593 | { | |
594 | register vm_object_t new_copy; | |
595 | register vm_object_t old_copy; | |
596 | vm_offset_t new_start, new_end; | |
597 | ||
598 | register vm_page_t p; | |
599 | ||
ffe0d082 | 600 | if (src_object == NULL) { |
175f072e KM |
601 | /* |
602 | * Nothing to copy | |
603 | */ | |
ffe0d082 | 604 | *dst_object = NULL; |
175f072e KM |
605 | *dst_offset = 0; |
606 | *src_needs_copy = FALSE; | |
607 | return; | |
608 | } | |
609 | ||
610 | /* | |
611 | * If the object's pager is null_pager or the | |
612 | * default pager, we don't have to make a copy | |
613 | * of it. Instead, we set the needs copy flag and | |
614 | * make a shadow later. | |
615 | */ | |
616 | ||
617 | vm_object_lock(src_object); | |
ffe0d082 | 618 | if (src_object->pager == NULL || |
175f072e KM |
619 | src_object->internal) { |
620 | ||
621 | /* | |
622 | * Make another reference to the object | |
623 | */ | |
624 | src_object->ref_count++; | |
625 | ||
626 | /* | |
627 | * Mark all of the pages copy-on-write. | |
628 | */ | |
629 | for (p = (vm_page_t) queue_first(&src_object->memq); | |
630 | !queue_end(&src_object->memq, (queue_entry_t)p); | |
631 | p = (vm_page_t) queue_next(&p->listq)) { | |
632 | if (src_offset <= p->offset && | |
633 | p->offset < src_offset + size) | |
634 | p->copy_on_write = TRUE; | |
635 | } | |
636 | vm_object_unlock(src_object); | |
637 | ||
638 | *dst_object = src_object; | |
639 | *dst_offset = src_offset; | |
640 | ||
641 | /* | |
642 | * Must make a shadow when write is desired | |
643 | */ | |
644 | *src_needs_copy = TRUE; | |
645 | return; | |
646 | } | |
647 | ||
648 | /* | |
649 | * Try to collapse the object before copying it. | |
650 | */ | |
651 | vm_object_collapse(src_object); | |
652 | ||
653 | /* | |
654 | * If the object has a pager, the pager wants to | |
655 | * see all of the changes. We need a copy-object | |
656 | * for the changed pages. | |
657 | * | |
658 | * If there is a copy-object, and it is empty, | |
659 | * no changes have been made to the object since the | |
660 | * copy-object was made. We can use the same copy- | |
661 | * object. | |
662 | */ | |
663 | ||
664 | Retry1: | |
665 | old_copy = src_object->copy; | |
ffe0d082 | 666 | if (old_copy != NULL) { |
175f072e KM |
667 | /* |
668 | * Try to get the locks (out of order) | |
669 | */ | |
670 | if (!vm_object_lock_try(old_copy)) { | |
671 | vm_object_unlock(src_object); | |
672 | ||
673 | /* should spin a bit here... */ | |
674 | vm_object_lock(src_object); | |
675 | goto Retry1; | |
676 | } | |
677 | ||
678 | if (old_copy->resident_page_count == 0 && | |
ffe0d082 | 679 | old_copy->pager == NULL) { |
175f072e KM |
680 | /* |
681 | * Return another reference to | |
682 | * the existing copy-object. | |
683 | */ | |
684 | old_copy->ref_count++; | |
685 | vm_object_unlock(old_copy); | |
686 | vm_object_unlock(src_object); | |
687 | *dst_object = old_copy; | |
688 | *dst_offset = src_offset; | |
689 | *src_needs_copy = FALSE; | |
690 | return; | |
691 | } | |
692 | vm_object_unlock(old_copy); | |
693 | } | |
694 | vm_object_unlock(src_object); | |
695 | ||
696 | /* | |
697 | * If the object has a pager, the pager wants | |
698 | * to see all of the changes. We must make | |
699 | * a copy-object and put the changed pages there. | |
700 | * | |
701 | * The copy-object is always made large enough to | |
702 | * completely shadow the original object, since | |
703 | * it may have several users who want to shadow | |
704 | * the original object at different points. | |
705 | */ | |
706 | ||
707 | new_copy = vm_object_allocate(src_object->size); | |
708 | ||
709 | Retry2: | |
710 | vm_object_lock(src_object); | |
711 | /* | |
712 | * Copy object may have changed while we were unlocked | |
713 | */ | |
714 | old_copy = src_object->copy; | |
ffe0d082 | 715 | if (old_copy != NULL) { |
175f072e KM |
716 | /* |
717 | * Try to get the locks (out of order) | |
718 | */ | |
719 | if (!vm_object_lock_try(old_copy)) { | |
720 | vm_object_unlock(src_object); | |
721 | goto Retry2; | |
722 | } | |
723 | ||
724 | /* | |
725 | * Consistency check | |
726 | */ | |
727 | if (old_copy->shadow != src_object || | |
728 | old_copy->shadow_offset != (vm_offset_t) 0) | |
729 | panic("vm_object_copy: copy/shadow inconsistency"); | |
730 | ||
731 | /* | |
732 | * Make the old copy-object shadow the new one. | |
733 | * It will receive no more pages from the original | |
734 | * object. | |
735 | */ | |
736 | ||
737 | src_object->ref_count--; /* remove ref. from old_copy */ | |
738 | old_copy->shadow = new_copy; | |
739 | new_copy->ref_count++; /* locking not needed - we | |
740 | have the only pointer */ | |
741 | vm_object_unlock(old_copy); /* done with old_copy */ | |
742 | } | |
743 | ||
744 | new_start = (vm_offset_t) 0; /* always shadow original at 0 */ | |
745 | new_end = (vm_offset_t) new_copy->size; /* for the whole object */ | |
746 | ||
747 | /* | |
748 | * Point the new copy at the existing object. | |
749 | */ | |
750 | ||
751 | new_copy->shadow = src_object; | |
752 | new_copy->shadow_offset = new_start; | |
753 | src_object->ref_count++; | |
754 | src_object->copy = new_copy; | |
755 | ||
756 | /* | |
757 | * Mark all the affected pages of the existing object | |
758 | * copy-on-write. | |
759 | */ | |
760 | p = (vm_page_t) queue_first(&src_object->memq); | |
761 | while (!queue_end(&src_object->memq, (queue_entry_t) p)) { | |
ae1e5b95 | 762 | if ((new_start <= p->offset) && (p->offset < new_end)) |
175f072e | 763 | p->copy_on_write = TRUE; |
175f072e KM |
764 | p = (vm_page_t) queue_next(&p->listq); |
765 | } | |
766 | ||
767 | vm_object_unlock(src_object); | |
768 | ||
769 | *dst_object = new_copy; | |
770 | *dst_offset = src_offset - new_start; | |
771 | *src_needs_copy = FALSE; | |
772 | } | |
773 | ||
774 | /* | |
775 | * vm_object_shadow: | |
776 | * | |
777 | * Create a new object which is backed by the | |
778 | * specified existing object range. The source | |
779 | * object reference is deallocated. | |
780 | * | |
781 | * The new object and offset into that object | |
782 | * are returned in the source parameters. | |
783 | */ | |
784 | ||
785 | void vm_object_shadow(object, offset, length) | |
786 | vm_object_t *object; /* IN/OUT */ | |
787 | vm_offset_t *offset; /* IN/OUT */ | |
788 | vm_size_t length; | |
789 | { | |
790 | register vm_object_t source; | |
791 | register vm_object_t result; | |
792 | ||
793 | source = *object; | |
794 | ||
795 | /* | |
796 | * Allocate a new object with the given length | |
797 | */ | |
798 | ||
ffe0d082 | 799 | if ((result = vm_object_allocate(length)) == NULL) |
175f072e KM |
800 | panic("vm_object_shadow: no object for shadowing"); |
801 | ||
802 | /* | |
803 | * The new object shadows the source object, adding | |
804 | * a reference to it. Our caller changes his reference | |
805 | * to point to the new object, removing a reference to | |
806 | * the source object. Net result: no change of reference | |
807 | * count. | |
808 | */ | |
809 | result->shadow = source; | |
810 | ||
811 | /* | |
812 | * Store the offset into the source object, | |
813 | * and fix up the offset into the new object. | |
814 | */ | |
815 | ||
816 | result->shadow_offset = *offset; | |
817 | ||
818 | /* | |
819 | * Return the new things | |
820 | */ | |
821 | ||
822 | *offset = 0; | |
823 | *object = result; | |
824 | } | |
825 | ||
826 | /* | |
827 | * Set the specified object's pager to the specified pager. | |
828 | */ | |
829 | ||
830 | void vm_object_setpager(object, pager, paging_offset, | |
831 | read_only) | |
832 | vm_object_t object; | |
833 | vm_pager_t pager; | |
834 | vm_offset_t paging_offset; | |
835 | boolean_t read_only; | |
836 | { | |
837 | #ifdef lint | |
838 | read_only++; /* No longer used */ | |
839 | #endif lint | |
840 | ||
841 | vm_object_lock(object); /* XXX ? */ | |
842 | object->pager = pager; | |
843 | object->paging_offset = paging_offset; | |
844 | vm_object_unlock(object); /* XXX ? */ | |
845 | } | |
846 | ||
847 | /* | |
848 | * vm_object_hash hashes the pager/id pair. | |
849 | */ | |
850 | ||
851 | #define vm_object_hash(pager) \ | |
852 | (((unsigned)pager)%VM_OBJECT_HASH_COUNT) | |
853 | ||
854 | /* | |
855 | * vm_object_lookup looks in the object cache for an object with the | |
856 | * specified pager and paging id. | |
857 | */ | |
858 | ||
859 | vm_object_t vm_object_lookup(pager) | |
860 | vm_pager_t pager; | |
861 | { | |
862 | register queue_t bucket; | |
863 | register vm_object_hash_entry_t entry; | |
864 | vm_object_t object; | |
865 | ||
866 | bucket = &vm_object_hashtable[vm_object_hash(pager)]; | |
867 | ||
868 | vm_object_cache_lock(); | |
869 | ||
870 | entry = (vm_object_hash_entry_t) queue_first(bucket); | |
871 | while (!queue_end(bucket, (queue_entry_t) entry)) { | |
872 | object = entry->object; | |
873 | if (object->pager == pager) { | |
874 | vm_object_lock(object); | |
875 | if (object->ref_count == 0) { | |
876 | queue_remove(&vm_object_cached_list, object, | |
877 | vm_object_t, cached_list); | |
878 | vm_object_cached--; | |
879 | } | |
880 | object->ref_count++; | |
881 | vm_object_unlock(object); | |
882 | vm_object_cache_unlock(); | |
883 | return(object); | |
884 | } | |
885 | entry = (vm_object_hash_entry_t) queue_next(&entry->hash_links); | |
886 | } | |
887 | ||
888 | vm_object_cache_unlock(); | |
ffe0d082 | 889 | return(NULL); |
175f072e KM |
890 | } |
891 | ||
892 | /* | |
893 | * vm_object_enter enters the specified object/pager/id into | |
894 | * the hash table. | |
895 | */ | |
896 | ||
897 | void vm_object_enter(object, pager) | |
898 | vm_object_t object; | |
899 | vm_pager_t pager; | |
900 | { | |
901 | register queue_t bucket; | |
902 | register vm_object_hash_entry_t entry; | |
903 | ||
904 | /* | |
905 | * We don't cache null objects, and we can't cache | |
906 | * objects with the null pager. | |
907 | */ | |
908 | ||
ffe0d082 | 909 | if (object == NULL) |
175f072e | 910 | return; |
ffe0d082 | 911 | if (pager == NULL) |
175f072e KM |
912 | return; |
913 | ||
914 | bucket = &vm_object_hashtable[vm_object_hash(pager)]; | |
915 | entry = (vm_object_hash_entry_t) | |
916 | malloc((u_long)sizeof *entry, M_VMOBJHASH, M_WAITOK); | |
917 | entry->object = object; | |
918 | object->can_persist = TRUE; | |
919 | ||
920 | vm_object_cache_lock(); | |
921 | queue_enter(bucket, entry, vm_object_hash_entry_t, hash_links); | |
922 | vm_object_cache_unlock(); | |
923 | } | |
924 | ||
925 | /* | |
926 | * vm_object_remove: | |
927 | * | |
928 | * Remove the pager from the hash table. | |
929 | * Note: This assumes that the object cache | |
930 | * is locked. XXX this should be fixed | |
931 | * by reorganizing vm_object_deallocate. | |
932 | */ | |
933 | vm_object_remove(pager) | |
934 | register vm_pager_t pager; | |
935 | { | |
936 | register queue_t bucket; | |
937 | register vm_object_hash_entry_t entry; | |
938 | register vm_object_t object; | |
939 | ||
940 | bucket = &vm_object_hashtable[vm_object_hash(pager)]; | |
941 | ||
942 | entry = (vm_object_hash_entry_t) queue_first(bucket); | |
943 | while (!queue_end(bucket, (queue_entry_t) entry)) { | |
944 | object = entry->object; | |
945 | if (object->pager == pager) { | |
946 | queue_remove(bucket, entry, vm_object_hash_entry_t, | |
947 | hash_links); | |
948 | free((caddr_t)entry, M_VMOBJHASH); | |
949 | break; | |
950 | } | |
951 | entry = (vm_object_hash_entry_t) queue_next(&entry->hash_links); | |
952 | } | |
953 | } | |
954 | ||
955 | /* | |
956 | * vm_object_cache_clear removes all objects from the cache. | |
957 | * | |
958 | */ | |
959 | ||
960 | void vm_object_cache_clear() | |
961 | { | |
962 | register vm_object_t object; | |
963 | ||
964 | /* | |
965 | * Remove each object in the cache by scanning down the | |
966 | * list of cached objects. | |
967 | */ | |
968 | vm_object_cache_lock(); | |
969 | while (!queue_empty(&vm_object_cached_list)) { | |
970 | object = (vm_object_t) queue_first(&vm_object_cached_list); | |
971 | vm_object_cache_unlock(); | |
972 | ||
973 | /* | |
974 | * Note: it is important that we use vm_object_lookup | |
975 | * to gain a reference, and not vm_object_reference, because | |
976 | * the logic for removing an object from the cache lies in | |
977 | * lookup. | |
978 | */ | |
979 | if (object != vm_object_lookup(object->pager)) | |
980 | panic("vm_object_cache_clear: I'm sooo confused."); | |
981 | pager_cache(object, FALSE); | |
982 | ||
983 | vm_object_cache_lock(); | |
984 | } | |
985 | vm_object_cache_unlock(); | |
986 | } | |
987 | ||
988 | boolean_t vm_object_collapse_allowed = TRUE; | |
989 | /* | |
990 | * vm_object_collapse: | |
991 | * | |
992 | * Collapse an object with the object backing it. | |
993 | * Pages in the backing object are moved into the | |
994 | * parent, and the backing object is deallocated. | |
995 | * | |
996 | * Requires that the object be locked and the page | |
997 | * queues be unlocked. | |
998 | * | |
999 | */ | |
1000 | void vm_object_collapse(object) | |
1001 | register vm_object_t object; | |
1002 | ||
1003 | { | |
1004 | register vm_object_t backing_object; | |
1005 | register vm_offset_t backing_offset; | |
1006 | register vm_size_t size; | |
1007 | register vm_offset_t new_offset; | |
1008 | register vm_page_t p, pp; | |
1009 | ||
1010 | if (!vm_object_collapse_allowed) | |
1011 | return; | |
1012 | ||
1013 | while (TRUE) { | |
1014 | /* | |
1015 | * Verify that the conditions are right for collapse: | |
1016 | * | |
1017 | * The object exists and no pages in it are currently | |
1018 | * being paged out (or have ever been paged out). | |
1019 | */ | |
ffe0d082 | 1020 | if (object == NULL || |
175f072e | 1021 | object->paging_in_progress != 0 || |
ffe0d082 | 1022 | object->pager != NULL) |
175f072e KM |
1023 | return; |
1024 | ||
1025 | /* | |
1026 | * There is a backing object, and | |
1027 | */ | |
1028 | ||
ffe0d082 | 1029 | if ((backing_object = object->shadow) == NULL) |
175f072e KM |
1030 | return; |
1031 | ||
1032 | vm_object_lock(backing_object); | |
1033 | /* | |
1034 | * ... | |
1035 | * The backing object is not read_only, | |
1036 | * and no pages in the backing object are | |
1037 | * currently being paged out. | |
1038 | * The backing object is internal. | |
1039 | */ | |
1040 | ||
1041 | if (!backing_object->internal || | |
1042 | backing_object->paging_in_progress != 0) { | |
1043 | vm_object_unlock(backing_object); | |
1044 | return; | |
1045 | } | |
1046 | ||
1047 | /* | |
1048 | * The backing object can't be a copy-object: | |
1049 | * the shadow_offset for the copy-object must stay | |
1050 | * as 0. Furthermore (for the 'we have all the | |
1051 | * pages' case), if we bypass backing_object and | |
1052 | * just shadow the next object in the chain, old | |
1053 | * pages from that object would then have to be copied | |
1054 | * BOTH into the (former) backing_object and into the | |
1055 | * parent object. | |
1056 | */ | |
ffe0d082 MK |
1057 | if (backing_object->shadow != NULL && |
1058 | backing_object->shadow->copy != NULL) { | |
175f072e KM |
1059 | vm_object_unlock(backing_object); |
1060 | return; | |
1061 | } | |
1062 | ||
1063 | /* | |
1064 | * We know that we can either collapse the backing | |
1065 | * object (if the parent is the only reference to | |
1066 | * it) or (perhaps) remove the parent's reference | |
1067 | * to it. | |
1068 | */ | |
1069 | ||
1070 | backing_offset = object->shadow_offset; | |
1071 | size = object->size; | |
1072 | ||
1073 | /* | |
1074 | * If there is exactly one reference to the backing | |
1075 | * object, we can collapse it into the parent. | |
1076 | */ | |
1077 | ||
1078 | if (backing_object->ref_count == 1) { | |
1079 | ||
1080 | /* | |
1081 | * We can collapse the backing object. | |
1082 | * | |
1083 | * Move all in-memory pages from backing_object | |
1084 | * to the parent. Pages that have been paged out | |
1085 | * will be overwritten by any of the parent's | |
1086 | * pages that shadow them. | |
1087 | */ | |
1088 | ||
1089 | while (!queue_empty(&backing_object->memq)) { | |
1090 | ||
1091 | p = (vm_page_t) | |
1092 | queue_first(&backing_object->memq); | |
1093 | ||
1094 | new_offset = (p->offset - backing_offset); | |
1095 | ||
1096 | /* | |
1097 | * If the parent has a page here, or if | |
1098 | * this page falls outside the parent, | |
1099 | * dispose of it. | |
1100 | * | |
1101 | * Otherwise, move it as planned. | |
1102 | */ | |
1103 | ||
1104 | if (p->offset < backing_offset || | |
1105 | new_offset >= size) { | |
1106 | vm_page_lock_queues(); | |
1107 | vm_page_free(p); | |
1108 | vm_page_unlock_queues(); | |
1109 | } else { | |
1110 | pp = vm_page_lookup(object, new_offset); | |
ffe0d082 | 1111 | if (pp != NULL && !pp->fake) { |
175f072e KM |
1112 | vm_page_lock_queues(); |
1113 | vm_page_free(p); | |
1114 | vm_page_unlock_queues(); | |
1115 | } | |
1116 | else { | |
1117 | if (pp) { | |
1118 | /* may be someone waiting for it */ | |
1119 | PAGE_WAKEUP(pp); | |
1120 | vm_page_lock_queues(); | |
1121 | vm_page_free(pp); | |
1122 | vm_page_unlock_queues(); | |
1123 | } | |
1124 | vm_page_rename(p, object, new_offset); | |
1125 | } | |
1126 | } | |
1127 | } | |
1128 | ||
1129 | /* | |
1130 | * Move the pager from backing_object to object. | |
1131 | * | |
1132 | * XXX We're only using part of the paging space | |
1133 | * for keeps now... we ought to discard the | |
1134 | * unused portion. | |
1135 | */ | |
1136 | ||
1137 | object->pager = backing_object->pager; | |
1138 | object->paging_offset += backing_offset; | |
1139 | ||
ffe0d082 | 1140 | backing_object->pager = NULL; |
175f072e KM |
1141 | |
1142 | /* | |
1143 | * Object now shadows whatever backing_object did. | |
1144 | * Note that the reference to backing_object->shadow | |
1145 | * moves from within backing_object to within object. | |
1146 | */ | |
1147 | ||
1148 | object->shadow = backing_object->shadow; | |
1149 | object->shadow_offset += backing_object->shadow_offset; | |
ffe0d082 MK |
1150 | if (object->shadow != NULL && |
1151 | object->shadow->copy != NULL) { | |
175f072e KM |
1152 | panic("vm_object_collapse: we collapsed a copy-object!"); |
1153 | } | |
1154 | /* | |
1155 | * Discard backing_object. | |
1156 | * | |
1157 | * Since the backing object has no pages, no | |
1158 | * pager left, and no object references within it, | |
1159 | * all that is necessary is to dispose of it. | |
1160 | */ | |
1161 | ||
1162 | vm_object_unlock(backing_object); | |
1163 | ||
1164 | simple_lock(&vm_object_list_lock); | |
1165 | queue_remove(&vm_object_list, backing_object, | |
1166 | vm_object_t, object_list); | |
1167 | vm_object_count--; | |
1168 | simple_unlock(&vm_object_list_lock); | |
1169 | ||
1170 | free((caddr_t)backing_object, M_VMOBJ); | |
1171 | ||
1172 | object_collapses++; | |
1173 | } | |
1174 | else { | |
1175 | /* | |
1176 | * If all of the pages in the backing object are | |
1177 | * shadowed by the parent object, the parent | |
1178 | * object no longer has to shadow the backing | |
1179 | * object; it can shadow the next one in the | |
1180 | * chain. | |
1181 | * | |
1182 | * The backing object must not be paged out - we'd | |
1183 | * have to check all of the paged-out pages, as | |
1184 | * well. | |
1185 | */ | |
1186 | ||
ffe0d082 | 1187 | if (backing_object->pager != NULL) { |
175f072e KM |
1188 | vm_object_unlock(backing_object); |
1189 | return; | |
1190 | } | |
1191 | ||
1192 | /* | |
1193 | * Should have a check for a 'small' number | |
1194 | * of pages here. | |
1195 | */ | |
1196 | ||
1197 | p = (vm_page_t) queue_first(&backing_object->memq); | |
1198 | while (!queue_end(&backing_object->memq, | |
1199 | (queue_entry_t) p)) { | |
1200 | ||
1201 | new_offset = (p->offset - backing_offset); | |
1202 | ||
1203 | /* | |
1204 | * If the parent has a page here, or if | |
1205 | * this page falls outside the parent, | |
1206 | * keep going. | |
1207 | * | |
1208 | * Otherwise, the backing_object must be | |
1209 | * left in the chain. | |
1210 | */ | |
1211 | ||
1212 | if (p->offset >= backing_offset && | |
1213 | new_offset <= size && | |
1214 | ((pp = vm_page_lookup(object, new_offset)) | |
ffe0d082 | 1215 | == NULL || |
175f072e KM |
1216 | pp->fake)) { |
1217 | /* | |
1218 | * Page still needed. | |
1219 | * Can't go any further. | |
1220 | */ | |
1221 | vm_object_unlock(backing_object); | |
1222 | return; | |
1223 | } | |
1224 | p = (vm_page_t) queue_next(&p->listq); | |
1225 | } | |
1226 | ||
1227 | /* | |
1228 | * Make the parent shadow the next object | |
1229 | * in the chain. Deallocating backing_object | |
1230 | * will not remove it, since its reference | |
1231 | * count is at least 2. | |
1232 | */ | |
1233 | ||
1234 | vm_object_reference(object->shadow = backing_object->shadow); | |
1235 | object->shadow_offset += backing_object->shadow_offset; | |
1236 | ||
1237 | /* Drop the reference count on backing_object. | |
1238 | * Since its ref_count was at least 2, it | |
1239 | * will not vanish; so we don't need to call | |
1240 | * vm_object_deallocate. | |
1241 | */ | |
1242 | backing_object->ref_count--; | |
1243 | vm_object_unlock(backing_object); | |
1244 | ||
1245 | object_bypasses ++; | |
1246 | ||
1247 | } | |
1248 | ||
1249 | /* | |
1250 | * Try again with this object's new backing object. | |
1251 | */ | |
1252 | } | |
1253 | } | |
1254 | ||
1255 | /* | |
1256 | * vm_object_page_remove: [internal] | |
1257 | * | |
1258 | * Removes all physical pages in the specified | |
1259 | * object range from the object's list of pages. | |
1260 | * | |
1261 | * The object must be locked. | |
1262 | */ | |
1263 | void vm_object_page_remove(object, start, end) | |
1264 | register vm_object_t object; | |
1265 | register vm_offset_t start; | |
1266 | register vm_offset_t end; | |
1267 | { | |
1268 | register vm_page_t p, next; | |
1269 | ||
ffe0d082 | 1270 | if (object == NULL) |
175f072e KM |
1271 | return; |
1272 | ||
1273 | p = (vm_page_t) queue_first(&object->memq); | |
1274 | while (!queue_end(&object->memq, (queue_entry_t) p)) { | |
1275 | next = (vm_page_t) queue_next(&p->listq); | |
1276 | if ((start <= p->offset) && (p->offset < end)) { | |
ae1e5b95 | 1277 | pmap_page_protect(VM_PAGE_TO_PHYS(p), VM_PROT_NONE); |
175f072e KM |
1278 | vm_page_lock_queues(); |
1279 | vm_page_free(p); | |
1280 | vm_page_unlock_queues(); | |
1281 | } | |
1282 | p = next; | |
1283 | } | |
1284 | } | |
1285 | ||
1286 | /* | |
1287 | * Routine: vm_object_coalesce | |
1288 | * Function: Coalesces two objects backing up adjoining | |
1289 | * regions of memory into a single object. | |
1290 | * | |
1291 | * returns TRUE if objects were combined. | |
1292 | * | |
1293 | * NOTE: Only works at the moment if the second object is NULL - | |
1294 | * if it's not, which object do we lock first? | |
1295 | * | |
1296 | * Parameters: | |
1297 | * prev_object First object to coalesce | |
1298 | * prev_offset Offset into prev_object | |
1299 | * next_object Second object into coalesce | |
1300 | * next_offset Offset into next_object | |
1301 | * | |
1302 | * prev_size Size of reference to prev_object | |
1303 | * next_size Size of reference to next_object | |
1304 | * | |
1305 | * Conditions: | |
1306 | * The object must *not* be locked. | |
1307 | */ | |
1308 | boolean_t vm_object_coalesce(prev_object, next_object, | |
1309 | prev_offset, next_offset, | |
1310 | prev_size, next_size) | |
1311 | ||
1312 | register vm_object_t prev_object; | |
1313 | vm_object_t next_object; | |
1314 | vm_offset_t prev_offset, next_offset; | |
1315 | vm_size_t prev_size, next_size; | |
1316 | { | |
1317 | vm_size_t newsize; | |
1318 | ||
1319 | #ifdef lint | |
1320 | next_offset++; | |
1321 | #endif lint | |
1322 | ||
ffe0d082 | 1323 | if (next_object != NULL) { |
175f072e KM |
1324 | return(FALSE); |
1325 | } | |
1326 | ||
ffe0d082 | 1327 | if (prev_object == NULL) { |
175f072e KM |
1328 | return(TRUE); |
1329 | } | |
1330 | ||
1331 | vm_object_lock(prev_object); | |
1332 | ||
1333 | /* | |
1334 | * Try to collapse the object first | |
1335 | */ | |
1336 | vm_object_collapse(prev_object); | |
1337 | ||
1338 | /* | |
1339 | * Can't coalesce if: | |
1340 | * . more than one reference | |
1341 | * . paged out | |
1342 | * . shadows another object | |
1343 | * . has a copy elsewhere | |
1344 | * (any of which mean that the pages not mapped to | |
1345 | * prev_entry may be in use anyway) | |
1346 | */ | |
1347 | ||
1348 | if (prev_object->ref_count > 1 || | |
ffe0d082 MK |
1349 | prev_object->pager != NULL || |
1350 | prev_object->shadow != NULL || | |
1351 | prev_object->copy != NULL) { | |
175f072e KM |
1352 | vm_object_unlock(prev_object); |
1353 | return(FALSE); | |
1354 | } | |
1355 | ||
1356 | /* | |
1357 | * Remove any pages that may still be in the object from | |
1358 | * a previous deallocation. | |
1359 | */ | |
1360 | ||
1361 | vm_object_page_remove(prev_object, | |
1362 | prev_offset + prev_size, | |
1363 | prev_offset + prev_size + next_size); | |
1364 | ||
1365 | /* | |
1366 | * Extend the object if necessary. | |
1367 | */ | |
1368 | newsize = prev_offset + prev_size + next_size; | |
1369 | if (newsize > prev_object->size) | |
1370 | prev_object->size = newsize; | |
1371 | ||
1372 | vm_object_unlock(prev_object); | |
1373 | return(TRUE); | |
1374 | } | |
1375 | ||
1376 | /* | |
1377 | * vm_object_print: [ debug ] | |
1378 | */ | |
1379 | void vm_object_print(object, full) | |
1380 | vm_object_t object; | |
1381 | boolean_t full; | |
1382 | { | |
1383 | register vm_page_t p; | |
1384 | extern indent; | |
1385 | ||
1386 | register int count; | |
1387 | ||
ffe0d082 | 1388 | if (object == NULL) |
175f072e KM |
1389 | return; |
1390 | ||
1391 | iprintf("Object 0x%x: size=0x%x, res=%d, ref=%d, ", | |
1392 | (int) object, (int) object->size, | |
1393 | object->resident_page_count, object->ref_count); | |
1394 | printf("pager=0x%x+0x%x, shadow=(0x%x)+0x%x\n", | |
1395 | (int) object->pager, (int) object->paging_offset, | |
1396 | (int) object->shadow, (int) object->shadow_offset); | |
1397 | printf("cache: next=0x%x, prev=0x%x\n", | |
1398 | object->cached_list.next, object->cached_list.prev); | |
1399 | ||
1400 | if (!full) | |
1401 | return; | |
1402 | ||
1403 | indent += 2; | |
1404 | count = 0; | |
1405 | p = (vm_page_t) queue_first(&object->memq); | |
1406 | while (!queue_end(&object->memq, (queue_entry_t) p)) { | |
1407 | if (count == 0) | |
1408 | iprintf("memory:="); | |
1409 | else if (count == 6) { | |
1410 | printf("\n"); | |
1411 | iprintf(" ..."); | |
1412 | count = 0; | |
1413 | } else | |
1414 | printf(","); | |
1415 | count++; | |
1416 | ||
1417 | printf("(off=0x%x,page=0x%x)", p->offset, VM_PAGE_TO_PHYS(p)); | |
1418 | p = (vm_page_t) queue_next(&p->listq); | |
1419 | } | |
1420 | if (count != 0) | |
1421 | printf("\n"); | |
1422 | indent -= 2; | |
1423 | } |