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175f072e | 1 | /* |
ad0f93d2 KB |
2 | * Copyright (c) 1991, 1993 |
3 | * The Regents of the University of California. All rights reserved. | |
175f072e KM |
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 | * |
2fe84727 | 10 | * @(#)vm_object.c 8.7 (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 | ||
0b1533b1 KB |
43 | #include <sys/param.h> |
44 | #include <sys/systm.h> | |
45 | #include <sys/malloc.h> | |
ffe0d082 | 46 | |
0b1533b1 KB |
47 | #include <vm/vm.h> |
48 | #include <vm/vm_page.h> | |
175f072e KM |
49 | |
50 | /* | |
51 | * Virtual memory objects maintain the actual data | |
52 | * associated with allocated virtual memory. A given | |
53 | * page of memory exists within exactly one object. | |
54 | * | |
55 | * An object is only deallocated when all "references" | |
56 | * are given up. Only one "reference" to a given | |
57 | * region of an object should be writeable. | |
58 | * | |
59 | * Associated with each object is a list of all resident | |
60 | * memory pages belonging to that object; this list is | |
61 | * maintained by the "vm_page" module, and locked by the object's | |
62 | * lock. | |
63 | * | |
64 | * Each object also records a "pager" routine which is | |
65 | * used to retrieve (and store) pages to the proper backing | |
66 | * storage. In addition, objects may be backed by other | |
67 | * objects from which they were virtual-copied. | |
68 | * | |
69 | * The only items within the object structure which are | |
70 | * modified after time of creation are: | |
71 | * reference count locked by object's lock | |
72 | * pager routine locked by object's lock | |
73 | * | |
74 | */ | |
75 | ||
76 | struct vm_object kernel_object_store; | |
77 | struct vm_object kmem_object_store; | |
78 | ||
79 | #define VM_OBJECT_HASH_COUNT 157 | |
80 | ||
4fee7222 KM |
81 | int vm_cache_max = 100; /* can patch if necessary */ |
82 | struct vm_object_hash_head vm_object_hashtable[VM_OBJECT_HASH_COUNT]; | |
175f072e KM |
83 | |
84 | long object_collapses = 0; | |
85 | long object_bypasses = 0; | |
86 | ||
0b1533b1 KB |
87 | static void _vm_object_allocate __P((vm_size_t, vm_object_t)); |
88 | ||
175f072e KM |
89 | /* |
90 | * vm_object_init: | |
91 | * | |
92 | * Initialize the VM objects module. | |
93 | */ | |
70b9635a CD |
94 | void |
95 | vm_object_init(size) | |
5d30158d | 96 | vm_size_t size; |
175f072e KM |
97 | { |
98 | register int i; | |
99 | ||
4fee7222 KM |
100 | TAILQ_INIT(&vm_object_cached_list); |
101 | TAILQ_INIT(&vm_object_list); | |
175f072e KM |
102 | vm_object_count = 0; |
103 | simple_lock_init(&vm_cache_lock); | |
104 | simple_lock_init(&vm_object_list_lock); | |
105 | ||
106 | for (i = 0; i < VM_OBJECT_HASH_COUNT; i++) | |
4fee7222 | 107 | TAILQ_INIT(&vm_object_hashtable[i]); |
175f072e KM |
108 | |
109 | kernel_object = &kernel_object_store; | |
5d30158d | 110 | _vm_object_allocate(size, kernel_object); |
175f072e KM |
111 | |
112 | kmem_object = &kmem_object_store; | |
113 | _vm_object_allocate(VM_KMEM_SIZE + VM_MBUF_SIZE, kmem_object); | |
114 | } | |
115 | ||
116 | /* | |
117 | * vm_object_allocate: | |
118 | * | |
119 | * Returns a new object with the given size. | |
120 | */ | |
121 | ||
70b9635a CD |
122 | vm_object_t |
123 | vm_object_allocate(size) | |
175f072e KM |
124 | vm_size_t size; |
125 | { | |
126 | register vm_object_t result; | |
127 | ||
128 | result = (vm_object_t) | |
129 | malloc((u_long)sizeof *result, M_VMOBJ, M_WAITOK); | |
130 | ||
131 | _vm_object_allocate(size, result); | |
132 | ||
133 | return(result); | |
134 | } | |
135 | ||
0b1533b1 | 136 | static void |
175f072e KM |
137 | _vm_object_allocate(size, object) |
138 | vm_size_t size; | |
139 | register vm_object_t object; | |
140 | { | |
4fee7222 | 141 | TAILQ_INIT(&object->memq); |
175f072e KM |
142 | vm_object_lock_init(object); |
143 | object->ref_count = 1; | |
144 | object->resident_page_count = 0; | |
145 | object->size = size; | |
d4ab8fb9 | 146 | object->flags = OBJ_INTERNAL; /* vm_allocate_with_pager will reset */ |
175f072e | 147 | object->paging_in_progress = 0; |
ffe0d082 | 148 | object->copy = NULL; |
175f072e KM |
149 | |
150 | /* | |
151 | * Object starts out read-write, with no pager. | |
152 | */ | |
153 | ||
ffe0d082 | 154 | object->pager = NULL; |
175f072e | 155 | object->paging_offset = 0; |
ffe0d082 | 156 | object->shadow = NULL; |
175f072e KM |
157 | object->shadow_offset = (vm_offset_t) 0; |
158 | ||
159 | simple_lock(&vm_object_list_lock); | |
4fee7222 | 160 | TAILQ_INSERT_TAIL(&vm_object_list, object, object_list); |
175f072e | 161 | vm_object_count++; |
7300cb48 | 162 | cnt.v_nzfod += atop(size); |
175f072e KM |
163 | simple_unlock(&vm_object_list_lock); |
164 | } | |
165 | ||
166 | /* | |
167 | * vm_object_reference: | |
168 | * | |
169 | * Gets another reference to the given object. | |
170 | */ | |
70b9635a CD |
171 | void |
172 | vm_object_reference(object) | |
175f072e KM |
173 | register vm_object_t object; |
174 | { | |
ffe0d082 | 175 | if (object == NULL) |
175f072e KM |
176 | return; |
177 | ||
178 | vm_object_lock(object); | |
179 | object->ref_count++; | |
180 | vm_object_unlock(object); | |
181 | } | |
182 | ||
183 | /* | |
184 | * vm_object_deallocate: | |
185 | * | |
186 | * Release a reference to the specified object, | |
187 | * gained either through a vm_object_allocate | |
188 | * or a vm_object_reference call. When all references | |
189 | * are gone, storage associated with this object | |
190 | * may be relinquished. | |
191 | * | |
192 | * No object may be locked. | |
193 | */ | |
70b9635a CD |
194 | void |
195 | vm_object_deallocate(object) | |
175f072e KM |
196 | register vm_object_t object; |
197 | { | |
198 | vm_object_t temp; | |
199 | ||
ffe0d082 | 200 | while (object != NULL) { |
175f072e KM |
201 | |
202 | /* | |
203 | * The cache holds a reference (uncounted) to | |
204 | * the object; we must lock it before removing | |
205 | * the object. | |
206 | */ | |
207 | ||
208 | vm_object_cache_lock(); | |
209 | ||
210 | /* | |
211 | * Lose the reference | |
212 | */ | |
213 | vm_object_lock(object); | |
214 | if (--(object->ref_count) != 0) { | |
215 | ||
216 | /* | |
217 | * If there are still references, then | |
218 | * we are done. | |
219 | */ | |
220 | vm_object_unlock(object); | |
221 | vm_object_cache_unlock(); | |
222 | return; | |
223 | } | |
224 | ||
225 | /* | |
226 | * See if this object can persist. If so, enter | |
227 | * it in the cache, then deactivate all of its | |
228 | * pages. | |
229 | */ | |
230 | ||
d4ab8fb9 | 231 | if (object->flags & OBJ_CANPERSIST) { |
175f072e | 232 | |
4fee7222 KM |
233 | TAILQ_INSERT_TAIL(&vm_object_cached_list, object, |
234 | cached_list); | |
175f072e KM |
235 | vm_object_cached++; |
236 | vm_object_cache_unlock(); | |
237 | ||
238 | vm_object_deactivate_pages(object); | |
239 | vm_object_unlock(object); | |
240 | ||
241 | vm_object_cache_trim(); | |
242 | return; | |
243 | } | |
244 | ||
245 | /* | |
246 | * Make sure no one can look us up now. | |
247 | */ | |
248 | vm_object_remove(object->pager); | |
249 | vm_object_cache_unlock(); | |
250 | ||
251 | temp = object->shadow; | |
252 | vm_object_terminate(object); | |
253 | /* unlocks and deallocates object */ | |
254 | object = temp; | |
255 | } | |
256 | } | |
257 | ||
258 | ||
259 | /* | |
260 | * vm_object_terminate actually destroys the specified object, freeing | |
261 | * up all previously used resources. | |
262 | * | |
263 | * The object must be locked. | |
264 | */ | |
70b9635a CD |
265 | void |
266 | vm_object_terminate(object) | |
175f072e KM |
267 | register vm_object_t object; |
268 | { | |
269 | register vm_page_t p; | |
270 | vm_object_t shadow_object; | |
271 | ||
272 | /* | |
273 | * Detach the object from its shadow if we are the shadow's | |
274 | * copy. | |
275 | */ | |
ffe0d082 | 276 | if ((shadow_object = object->shadow) != NULL) { |
175f072e KM |
277 | vm_object_lock(shadow_object); |
278 | if (shadow_object->copy == object) | |
ffe0d082 | 279 | shadow_object->copy = NULL; |
175f072e | 280 | #if 0 |
ffe0d082 | 281 | else if (shadow_object->copy != NULL) |
175f072e KM |
282 | panic("vm_object_terminate: copy/shadow inconsistency"); |
283 | #endif | |
284 | vm_object_unlock(shadow_object); | |
285 | } | |
286 | ||
287 | /* | |
888963d8 | 288 | * Wait until the pageout daemon is through with the object. |
175f072e | 289 | */ |
888963d8 | 290 | while (object->paging_in_progress) { |
70b9635a | 291 | vm_object_sleep(object, object, FALSE); |
175f072e KM |
292 | vm_object_lock(object); |
293 | } | |
294 | ||
175f072e | 295 | /* |
888963d8 MH |
296 | * If not an internal object clean all the pages, removing them |
297 | * from paging queues as we go. | |
7300cb48 MH |
298 | * |
299 | * XXX need to do something in the event of a cleaning error. | |
175f072e | 300 | */ |
888963d8 | 301 | if ((object->flags & OBJ_INTERNAL) == 0) { |
7300cb48 | 302 | (void) vm_object_page_clean(object, 0, 0, TRUE, TRUE); |
888963d8 | 303 | vm_object_unlock(object); |
175f072e | 304 | } |
175f072e KM |
305 | |
306 | /* | |
888963d8 MH |
307 | * Now free the pages. |
308 | * For internal objects, this also removes them from paging queues. | |
175f072e | 309 | */ |
4fee7222 | 310 | while ((p = object->memq.tqh_first) != NULL) { |
175f072e | 311 | VM_PAGE_CHECK(p); |
175f072e KM |
312 | vm_page_lock_queues(); |
313 | vm_page_free(p); | |
7300cb48 | 314 | cnt.v_pfree++; |
175f072e KM |
315 | vm_page_unlock_queues(); |
316 | } | |
888963d8 MH |
317 | if ((object->flags & OBJ_INTERNAL) == 0) |
318 | vm_object_unlock(object); | |
175f072e KM |
319 | |
320 | /* | |
888963d8 | 321 | * Let the pager know object is dead. |
175f072e | 322 | */ |
ffe0d082 | 323 | if (object->pager != NULL) |
175f072e KM |
324 | vm_pager_deallocate(object->pager); |
325 | ||
175f072e | 326 | simple_lock(&vm_object_list_lock); |
4fee7222 | 327 | TAILQ_REMOVE(&vm_object_list, object, object_list); |
175f072e KM |
328 | vm_object_count--; |
329 | simple_unlock(&vm_object_list_lock); | |
330 | ||
331 | /* | |
888963d8 | 332 | * Free the space for the object. |
175f072e | 333 | */ |
175f072e KM |
334 | free((caddr_t)object, M_VMOBJ); |
335 | } | |
336 | ||
337 | /* | |
338 | * vm_object_page_clean | |
339 | * | |
340 | * Clean all dirty pages in the specified range of object. | |
7300cb48 | 341 | * If syncio is TRUE, page cleaning is done synchronously. |
25746cce | 342 | * If de_queue is TRUE, pages are removed from any paging queue |
888963d8 MH |
343 | * they were on, otherwise they are left on whatever queue they |
344 | * were on before the cleaning operation began. | |
175f072e KM |
345 | * |
346 | * Odd semantics: if start == end, we clean everything. | |
347 | * | |
348 | * The object must be locked. | |
7300cb48 MH |
349 | * |
350 | * Returns TRUE if all was well, FALSE if there was a pager error | |
351 | * somewhere. We attempt to clean (and dequeue) all pages regardless | |
352 | * of where an error occurs. | |
175f072e | 353 | */ |
7300cb48 MH |
354 | boolean_t |
355 | vm_object_page_clean(object, start, end, syncio, de_queue) | |
175f072e KM |
356 | register vm_object_t object; |
357 | register vm_offset_t start; | |
358 | register vm_offset_t end; | |
7300cb48 | 359 | boolean_t syncio; |
25746cce | 360 | boolean_t de_queue; |
175f072e KM |
361 | { |
362 | register vm_page_t p; | |
888963d8 | 363 | int onqueue; |
7300cb48 MH |
364 | boolean_t noerror = TRUE; |
365 | ||
366 | if (object == NULL) | |
367 | return (TRUE); | |
368 | ||
369 | /* | |
370 | * If it is an internal object and there is no pager, attempt to | |
371 | * allocate one. Note that vm_object_collapse may relocate one | |
372 | * from a collapsed object so we must recheck afterward. | |
373 | */ | |
374 | if ((object->flags & OBJ_INTERNAL) && object->pager == NULL) { | |
375 | vm_object_collapse(object); | |
376 | if (object->pager == NULL) { | |
377 | vm_pager_t pager; | |
175f072e | 378 | |
7300cb48 MH |
379 | vm_object_unlock(object); |
380 | pager = vm_pager_allocate(PG_DFLT, (caddr_t)0, | |
381 | object->size, VM_PROT_ALL, | |
382 | (vm_offset_t)0); | |
383 | if (pager) | |
384 | vm_object_setpager(object, pager, 0, FALSE); | |
385 | vm_object_lock(object); | |
386 | } | |
387 | } | |
ffe0d082 | 388 | if (object->pager == NULL) |
7300cb48 | 389 | return (FALSE); |
175f072e KM |
390 | |
391 | again: | |
888963d8 MH |
392 | /* |
393 | * Wait until the pageout daemon is through with the object. | |
394 | */ | |
395 | while (object->paging_in_progress) { | |
70b9635a | 396 | vm_object_sleep(object, object, FALSE); |
888963d8 MH |
397 | vm_object_lock(object); |
398 | } | |
399 | /* | |
400 | * Loop through the object page list cleaning as necessary. | |
401 | */ | |
4fee7222 | 402 | for (p = object->memq.tqh_first; p != NULL; p = p->listq.tqe_next) { |
7300cb48 MH |
403 | if ((start == end || p->offset >= start && p->offset < end) && |
404 | !(p->flags & PG_FICTITIOUS)) { | |
2cbf9af3 KM |
405 | if ((p->flags & PG_CLEAN) && |
406 | pmap_is_modified(VM_PAGE_TO_PHYS(p))) | |
407 | p->flags &= ~PG_CLEAN; | |
888963d8 MH |
408 | /* |
409 | * Remove the page from any paging queue. | |
410 | * This needs to be done if either we have been | |
411 | * explicitly asked to do so or it is about to | |
412 | * be cleaned (see comment below). | |
413 | */ | |
2cbf9af3 | 414 | if (de_queue || !(p->flags & PG_CLEAN)) { |
888963d8 | 415 | vm_page_lock_queues(); |
2cbf9af3 | 416 | if (p->flags & PG_ACTIVE) { |
4fee7222 KM |
417 | TAILQ_REMOVE(&vm_page_queue_active, |
418 | p, pageq); | |
2cbf9af3 | 419 | p->flags &= ~PG_ACTIVE; |
888963d8 MH |
420 | cnt.v_active_count--; |
421 | onqueue = 1; | |
2cbf9af3 | 422 | } else if (p->flags & PG_INACTIVE) { |
4fee7222 KM |
423 | TAILQ_REMOVE(&vm_page_queue_inactive, |
424 | p, pageq); | |
2cbf9af3 | 425 | p->flags &= ~PG_INACTIVE; |
888963d8 MH |
426 | cnt.v_inactive_count--; |
427 | onqueue = -1; | |
428 | } else | |
429 | onqueue = 0; | |
430 | vm_page_unlock_queues(); | |
431 | } | |
432 | /* | |
433 | * To ensure the state of the page doesn't change | |
434 | * during the clean operation we do two things. | |
7300cb48 MH |
435 | * First we set the busy bit and write-protect all |
436 | * mappings to ensure that write accesses to the | |
888963d8 MH |
437 | * page block (in vm_fault). Second, we remove |
438 | * the page from any paging queue to foil the | |
439 | * pageout daemon (vm_pageout_scan). | |
440 | */ | |
7300cb48 | 441 | pmap_page_protect(VM_PAGE_TO_PHYS(p), VM_PROT_READ); |
2cbf9af3 KM |
442 | if (!(p->flags & PG_CLEAN)) { |
443 | p->flags |= PG_BUSY; | |
175f072e KM |
444 | object->paging_in_progress++; |
445 | vm_object_unlock(object); | |
7300cb48 MH |
446 | /* |
447 | * XXX if put fails we mark the page as | |
448 | * clean to avoid an infinite loop. | |
449 | * Will loose changes to the page. | |
450 | */ | |
451 | if (vm_pager_put(object->pager, p, syncio)) { | |
452 | printf("%s: pager_put error\n", | |
453 | "vm_object_page_clean"); | |
454 | p->flags |= PG_CLEAN; | |
455 | noerror = FALSE; | |
456 | } | |
175f072e KM |
457 | vm_object_lock(object); |
458 | object->paging_in_progress--; | |
25746cce | 459 | if (!de_queue && onqueue) { |
888963d8 MH |
460 | vm_page_lock_queues(); |
461 | if (onqueue > 0) | |
462 | vm_page_activate(p); | |
463 | else | |
464 | vm_page_deactivate(p); | |
465 | vm_page_unlock_queues(); | |
466 | } | |
2cbf9af3 | 467 | p->flags &= ~PG_BUSY; |
175f072e KM |
468 | PAGE_WAKEUP(p); |
469 | goto again; | |
470 | } | |
471 | } | |
175f072e | 472 | } |
7300cb48 | 473 | return (noerror); |
175f072e KM |
474 | } |
475 | ||
476 | /* | |
477 | * vm_object_deactivate_pages | |
478 | * | |
479 | * Deactivate all pages in the specified object. (Keep its pages | |
480 | * in memory even though it is no longer referenced.) | |
481 | * | |
482 | * The object must be locked. | |
483 | */ | |
0b1533b1 | 484 | void |
175f072e KM |
485 | vm_object_deactivate_pages(object) |
486 | register vm_object_t object; | |
487 | { | |
488 | register vm_page_t p, next; | |
489 | ||
4fee7222 KM |
490 | for (p = object->memq.tqh_first; p != NULL; p = next) { |
491 | next = p->listq.tqe_next; | |
175f072e KM |
492 | vm_page_lock_queues(); |
493 | vm_page_deactivate(p); | |
494 | vm_page_unlock_queues(); | |
175f072e KM |
495 | } |
496 | } | |
497 | ||
498 | /* | |
499 | * Trim the object cache to size. | |
500 | */ | |
0b1533b1 | 501 | void |
175f072e KM |
502 | vm_object_cache_trim() |
503 | { | |
504 | register vm_object_t object; | |
505 | ||
506 | vm_object_cache_lock(); | |
507 | while (vm_object_cached > vm_cache_max) { | |
4fee7222 | 508 | object = vm_object_cached_list.tqh_first; |
175f072e KM |
509 | vm_object_cache_unlock(); |
510 | ||
511 | if (object != vm_object_lookup(object->pager)) | |
512 | panic("vm_object_deactivate: I'm sooo confused."); | |
513 | ||
514 | pager_cache(object, FALSE); | |
515 | ||
516 | vm_object_cache_lock(); | |
517 | } | |
518 | vm_object_cache_unlock(); | |
519 | } | |
520 | ||
175f072e KM |
521 | /* |
522 | * vm_object_pmap_copy: | |
523 | * | |
524 | * Makes all physical pages in the specified | |
525 | * object range copy-on-write. No writeable | |
526 | * references to these pages should remain. | |
527 | * | |
528 | * The object must *not* be locked. | |
529 | */ | |
70b9635a CD |
530 | void |
531 | vm_object_pmap_copy(object, start, end) | |
175f072e KM |
532 | register vm_object_t object; |
533 | register vm_offset_t start; | |
534 | register vm_offset_t end; | |
535 | { | |
536 | register vm_page_t p; | |
537 | ||
ffe0d082 | 538 | if (object == NULL) |
175f072e KM |
539 | return; |
540 | ||
541 | vm_object_lock(object); | |
4fee7222 | 542 | for (p = object->memq.tqh_first; p != NULL; p = p->listq.tqe_next) { |
175f072e | 543 | if ((start <= p->offset) && (p->offset < end)) { |
ae1e5b95 | 544 | pmap_page_protect(VM_PAGE_TO_PHYS(p), VM_PROT_READ); |
2cbf9af3 | 545 | p->flags |= PG_COPYONWRITE; |
175f072e | 546 | } |
175f072e KM |
547 | } |
548 | vm_object_unlock(object); | |
549 | } | |
550 | ||
551 | /* | |
552 | * vm_object_pmap_remove: | |
553 | * | |
554 | * Removes all physical pages in the specified | |
555 | * object range from all physical maps. | |
556 | * | |
557 | * The object must *not* be locked. | |
558 | */ | |
70b9635a CD |
559 | void |
560 | vm_object_pmap_remove(object, start, end) | |
175f072e KM |
561 | register vm_object_t object; |
562 | register vm_offset_t start; | |
563 | register vm_offset_t end; | |
564 | { | |
565 | register vm_page_t p; | |
566 | ||
ffe0d082 | 567 | if (object == NULL) |
175f072e KM |
568 | return; |
569 | ||
570 | vm_object_lock(object); | |
4fee7222 | 571 | for (p = object->memq.tqh_first; p != NULL; p = p->listq.tqe_next) |
ae1e5b95 MH |
572 | if ((start <= p->offset) && (p->offset < end)) |
573 | pmap_page_protect(VM_PAGE_TO_PHYS(p), VM_PROT_NONE); | |
175f072e KM |
574 | vm_object_unlock(object); |
575 | } | |
576 | ||
577 | /* | |
578 | * vm_object_copy: | |
579 | * | |
580 | * Create a new object which is a copy of an existing | |
581 | * object, and mark all of the pages in the existing | |
582 | * object 'copy-on-write'. The new object has one reference. | |
583 | * Returns the new object. | |
584 | * | |
585 | * May defer the copy until later if the object is not backed | |
586 | * up by a non-default pager. | |
587 | */ | |
70b9635a CD |
588 | void |
589 | vm_object_copy(src_object, src_offset, size, | |
175f072e KM |
590 | dst_object, dst_offset, src_needs_copy) |
591 | register vm_object_t src_object; | |
592 | vm_offset_t src_offset; | |
593 | vm_size_t size; | |
594 | vm_object_t *dst_object; /* OUT */ | |
595 | vm_offset_t *dst_offset; /* OUT */ | |
596 | boolean_t *src_needs_copy; /* OUT */ | |
597 | { | |
598 | register vm_object_t new_copy; | |
599 | register vm_object_t old_copy; | |
600 | vm_offset_t new_start, new_end; | |
601 | ||
602 | register vm_page_t p; | |
603 | ||
ffe0d082 | 604 | if (src_object == NULL) { |
175f072e KM |
605 | /* |
606 | * Nothing to copy | |
607 | */ | |
ffe0d082 | 608 | *dst_object = NULL; |
175f072e KM |
609 | *dst_offset = 0; |
610 | *src_needs_copy = FALSE; | |
611 | return; | |
612 | } | |
613 | ||
614 | /* | |
615 | * If the object's pager is null_pager or the | |
616 | * default pager, we don't have to make a copy | |
617 | * of it. Instead, we set the needs copy flag and | |
618 | * make a shadow later. | |
619 | */ | |
620 | ||
621 | vm_object_lock(src_object); | |
ffe0d082 | 622 | if (src_object->pager == NULL || |
d4ab8fb9 | 623 | (src_object->flags & OBJ_INTERNAL)) { |
175f072e KM |
624 | |
625 | /* | |
626 | * Make another reference to the object | |
627 | */ | |
628 | src_object->ref_count++; | |
629 | ||
630 | /* | |
631 | * Mark all of the pages copy-on-write. | |
632 | */ | |
4fee7222 | 633 | for (p = src_object->memq.tqh_first; p; p = p->listq.tqe_next) |
175f072e KM |
634 | if (src_offset <= p->offset && |
635 | p->offset < src_offset + size) | |
2cbf9af3 | 636 | p->flags |= PG_COPYONWRITE; |
175f072e KM |
637 | vm_object_unlock(src_object); |
638 | ||
639 | *dst_object = src_object; | |
640 | *dst_offset = src_offset; | |
641 | ||
642 | /* | |
643 | * Must make a shadow when write is desired | |
644 | */ | |
645 | *src_needs_copy = TRUE; | |
646 | return; | |
647 | } | |
648 | ||
649 | /* | |
650 | * Try to collapse the object before copying it. | |
651 | */ | |
652 | vm_object_collapse(src_object); | |
653 | ||
654 | /* | |
655 | * If the object has a pager, the pager wants to | |
656 | * see all of the changes. We need a copy-object | |
657 | * for the changed pages. | |
658 | * | |
659 | * If there is a copy-object, and it is empty, | |
660 | * no changes have been made to the object since the | |
661 | * copy-object was made. We can use the same copy- | |
662 | * object. | |
663 | */ | |
664 | ||
665 | Retry1: | |
666 | old_copy = src_object->copy; | |
ffe0d082 | 667 | if (old_copy != NULL) { |
175f072e KM |
668 | /* |
669 | * Try to get the locks (out of order) | |
670 | */ | |
671 | if (!vm_object_lock_try(old_copy)) { | |
672 | vm_object_unlock(src_object); | |
673 | ||
674 | /* should spin a bit here... */ | |
675 | vm_object_lock(src_object); | |
676 | goto Retry1; | |
677 | } | |
678 | ||
679 | if (old_copy->resident_page_count == 0 && | |
ffe0d082 | 680 | old_copy->pager == NULL) { |
175f072e KM |
681 | /* |
682 | * Return another reference to | |
683 | * the existing copy-object. | |
684 | */ | |
685 | old_copy->ref_count++; | |
686 | vm_object_unlock(old_copy); | |
687 | vm_object_unlock(src_object); | |
688 | *dst_object = old_copy; | |
689 | *dst_offset = src_offset; | |
690 | *src_needs_copy = FALSE; | |
691 | return; | |
692 | } | |
693 | vm_object_unlock(old_copy); | |
694 | } | |
695 | vm_object_unlock(src_object); | |
696 | ||
697 | /* | |
698 | * If the object has a pager, the pager wants | |
699 | * to see all of the changes. We must make | |
700 | * a copy-object and put the changed pages there. | |
701 | * | |
702 | * The copy-object is always made large enough to | |
703 | * completely shadow the original object, since | |
704 | * it may have several users who want to shadow | |
705 | * the original object at different points. | |
706 | */ | |
707 | ||
708 | new_copy = vm_object_allocate(src_object->size); | |
709 | ||
710 | Retry2: | |
711 | vm_object_lock(src_object); | |
712 | /* | |
713 | * Copy object may have changed while we were unlocked | |
714 | */ | |
715 | old_copy = src_object->copy; | |
ffe0d082 | 716 | if (old_copy != NULL) { |
175f072e KM |
717 | /* |
718 | * Try to get the locks (out of order) | |
719 | */ | |
720 | if (!vm_object_lock_try(old_copy)) { | |
721 | vm_object_unlock(src_object); | |
722 | goto Retry2; | |
723 | } | |
724 | ||
725 | /* | |
726 | * Consistency check | |
727 | */ | |
728 | if (old_copy->shadow != src_object || | |
729 | old_copy->shadow_offset != (vm_offset_t) 0) | |
730 | panic("vm_object_copy: copy/shadow inconsistency"); | |
731 | ||
732 | /* | |
733 | * Make the old copy-object shadow the new one. | |
734 | * It will receive no more pages from the original | |
735 | * object. | |
736 | */ | |
737 | ||
738 | src_object->ref_count--; /* remove ref. from old_copy */ | |
739 | old_copy->shadow = new_copy; | |
740 | new_copy->ref_count++; /* locking not needed - we | |
741 | have the only pointer */ | |
742 | vm_object_unlock(old_copy); /* done with old_copy */ | |
743 | } | |
744 | ||
745 | new_start = (vm_offset_t) 0; /* always shadow original at 0 */ | |
746 | new_end = (vm_offset_t) new_copy->size; /* for the whole object */ | |
747 | ||
748 | /* | |
749 | * Point the new copy at the existing object. | |
750 | */ | |
751 | ||
752 | new_copy->shadow = src_object; | |
753 | new_copy->shadow_offset = new_start; | |
754 | src_object->ref_count++; | |
755 | src_object->copy = new_copy; | |
756 | ||
757 | /* | |
758 | * Mark all the affected pages of the existing object | |
759 | * copy-on-write. | |
760 | */ | |
4fee7222 | 761 | for (p = src_object->memq.tqh_first; p != NULL; p = p->listq.tqe_next) |
ae1e5b95 | 762 | if ((new_start <= p->offset) && (p->offset < new_end)) |
2cbf9af3 | 763 | p->flags |= PG_COPYONWRITE; |
175f072e KM |
764 | |
765 | vm_object_unlock(src_object); | |
766 | ||
767 | *dst_object = new_copy; | |
768 | *dst_offset = src_offset - new_start; | |
769 | *src_needs_copy = FALSE; | |
770 | } | |
771 | ||
772 | /* | |
773 | * vm_object_shadow: | |
774 | * | |
775 | * Create a new object which is backed by the | |
776 | * specified existing object range. The source | |
777 | * object reference is deallocated. | |
778 | * | |
779 | * The new object and offset into that object | |
780 | * are returned in the source parameters. | |
781 | */ | |
782 | ||
70b9635a CD |
783 | void |
784 | vm_object_shadow(object, offset, length) | |
175f072e KM |
785 | vm_object_t *object; /* IN/OUT */ |
786 | vm_offset_t *offset; /* IN/OUT */ | |
787 | vm_size_t length; | |
788 | { | |
789 | register vm_object_t source; | |
790 | register vm_object_t result; | |
791 | ||
792 | source = *object; | |
793 | ||
794 | /* | |
795 | * Allocate a new object with the given length | |
796 | */ | |
797 | ||
ffe0d082 | 798 | if ((result = vm_object_allocate(length)) == NULL) |
175f072e KM |
799 | panic("vm_object_shadow: no object for shadowing"); |
800 | ||
801 | /* | |
802 | * The new object shadows the source object, adding | |
803 | * a reference to it. Our caller changes his reference | |
804 | * to point to the new object, removing a reference to | |
805 | * the source object. Net result: no change of reference | |
806 | * count. | |
807 | */ | |
808 | result->shadow = source; | |
809 | ||
810 | /* | |
811 | * Store the offset into the source object, | |
812 | * and fix up the offset into the new object. | |
813 | */ | |
814 | ||
815 | result->shadow_offset = *offset; | |
816 | ||
817 | /* | |
818 | * Return the new things | |
819 | */ | |
820 | ||
821 | *offset = 0; | |
822 | *object = result; | |
823 | } | |
824 | ||
825 | /* | |
826 | * Set the specified object's pager to the specified pager. | |
827 | */ | |
828 | ||
70b9635a CD |
829 | void |
830 | vm_object_setpager(object, pager, paging_offset, | |
175f072e KM |
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 */ | |
1524bcb8 | 839 | #endif |
175f072e KM |
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) \ | |
70b9635a | 852 | (((unsigned long)pager)%VM_OBJECT_HASH_COUNT) |
175f072e KM |
853 | |
854 | /* | |
855 | * vm_object_lookup looks in the object cache for an object with the | |
856 | * specified pager and paging id. | |
857 | */ | |
858 | ||
70b9635a CD |
859 | vm_object_t |
860 | vm_object_lookup(pager) | |
175f072e KM |
861 | vm_pager_t pager; |
862 | { | |
175f072e KM |
863 | register vm_object_hash_entry_t entry; |
864 | vm_object_t object; | |
865 | ||
175f072e KM |
866 | vm_object_cache_lock(); |
867 | ||
4fee7222 KM |
868 | for (entry = vm_object_hashtable[vm_object_hash(pager)].tqh_first; |
869 | entry != NULL; | |
870 | entry = entry->hash_links.tqe_next) { | |
175f072e KM |
871 | object = entry->object; |
872 | if (object->pager == pager) { | |
873 | vm_object_lock(object); | |
874 | if (object->ref_count == 0) { | |
4fee7222 KM |
875 | TAILQ_REMOVE(&vm_object_cached_list, object, |
876 | cached_list); | |
175f072e KM |
877 | vm_object_cached--; |
878 | } | |
879 | object->ref_count++; | |
880 | vm_object_unlock(object); | |
881 | vm_object_cache_unlock(); | |
882 | return(object); | |
883 | } | |
175f072e KM |
884 | } |
885 | ||
886 | vm_object_cache_unlock(); | |
ffe0d082 | 887 | return(NULL); |
175f072e KM |
888 | } |
889 | ||
890 | /* | |
891 | * vm_object_enter enters the specified object/pager/id into | |
892 | * the hash table. | |
893 | */ | |
894 | ||
70b9635a CD |
895 | void |
896 | vm_object_enter(object, pager) | |
175f072e KM |
897 | vm_object_t object; |
898 | vm_pager_t pager; | |
899 | { | |
4fee7222 | 900 | struct vm_object_hash_head *bucket; |
175f072e KM |
901 | register vm_object_hash_entry_t entry; |
902 | ||
903 | /* | |
904 | * We don't cache null objects, and we can't cache | |
905 | * objects with the null pager. | |
906 | */ | |
907 | ||
ffe0d082 | 908 | if (object == NULL) |
175f072e | 909 | return; |
ffe0d082 | 910 | if (pager == NULL) |
175f072e KM |
911 | return; |
912 | ||
913 | bucket = &vm_object_hashtable[vm_object_hash(pager)]; | |
914 | entry = (vm_object_hash_entry_t) | |
915 | malloc((u_long)sizeof *entry, M_VMOBJHASH, M_WAITOK); | |
916 | entry->object = object; | |
d4ab8fb9 | 917 | object->flags |= OBJ_CANPERSIST; |
175f072e KM |
918 | |
919 | vm_object_cache_lock(); | |
4fee7222 | 920 | TAILQ_INSERT_TAIL(bucket, entry, hash_links); |
175f072e KM |
921 | vm_object_cache_unlock(); |
922 | } | |
923 | ||
924 | /* | |
925 | * vm_object_remove: | |
926 | * | |
927 | * Remove the pager from the hash table. | |
928 | * Note: This assumes that the object cache | |
929 | * is locked. XXX this should be fixed | |
930 | * by reorganizing vm_object_deallocate. | |
931 | */ | |
0b1533b1 | 932 | void |
175f072e KM |
933 | vm_object_remove(pager) |
934 | register vm_pager_t pager; | |
935 | { | |
4fee7222 | 936 | struct vm_object_hash_head *bucket; |
175f072e KM |
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 | ||
4fee7222 KM |
942 | for (entry = bucket->tqh_first; |
943 | entry != NULL; | |
944 | entry = entry->hash_links.tqe_next) { | |
175f072e KM |
945 | object = entry->object; |
946 | if (object->pager == pager) { | |
4fee7222 | 947 | TAILQ_REMOVE(bucket, entry, hash_links); |
175f072e KM |
948 | free((caddr_t)entry, M_VMOBJHASH); |
949 | break; | |
950 | } | |
175f072e KM |
951 | } |
952 | } | |
953 | ||
954 | /* | |
955 | * vm_object_cache_clear removes all objects from the cache. | |
956 | * | |
957 | */ | |
70b9635a CD |
958 | void |
959 | vm_object_cache_clear() | |
175f072e KM |
960 | { |
961 | register vm_object_t object; | |
962 | ||
963 | /* | |
964 | * Remove each object in the cache by scanning down the | |
965 | * list of cached objects. | |
966 | */ | |
967 | vm_object_cache_lock(); | |
4fee7222 | 968 | while ((object = vm_object_cached_list.tqh_first) != NULL) { |
175f072e KM |
969 | vm_object_cache_unlock(); |
970 | ||
971 | /* | |
972 | * Note: it is important that we use vm_object_lookup | |
973 | * to gain a reference, and not vm_object_reference, because | |
974 | * the logic for removing an object from the cache lies in | |
975 | * lookup. | |
976 | */ | |
977 | if (object != vm_object_lookup(object->pager)) | |
978 | panic("vm_object_cache_clear: I'm sooo confused."); | |
979 | pager_cache(object, FALSE); | |
980 | ||
981 | vm_object_cache_lock(); | |
982 | } | |
983 | vm_object_cache_unlock(); | |
984 | } | |
985 | ||
986 | boolean_t vm_object_collapse_allowed = TRUE; | |
987 | /* | |
988 | * vm_object_collapse: | |
989 | * | |
990 | * Collapse an object with the object backing it. | |
991 | * Pages in the backing object are moved into the | |
992 | * parent, and the backing object is deallocated. | |
993 | * | |
994 | * Requires that the object be locked and the page | |
995 | * queues be unlocked. | |
996 | * | |
997 | */ | |
70b9635a CD |
998 | void |
999 | vm_object_collapse(object) | |
175f072e KM |
1000 | register vm_object_t object; |
1001 | ||
1002 | { | |
1003 | register vm_object_t backing_object; | |
1004 | register vm_offset_t backing_offset; | |
1005 | register vm_size_t size; | |
1006 | register vm_offset_t new_offset; | |
1007 | register vm_page_t p, pp; | |
1008 | ||
1009 | if (!vm_object_collapse_allowed) | |
1010 | return; | |
1011 | ||
1012 | while (TRUE) { | |
1013 | /* | |
1014 | * Verify that the conditions are right for collapse: | |
1015 | * | |
1016 | * The object exists and no pages in it are currently | |
1017 | * being paged out (or have ever been paged out). | |
1018 | */ | |
ffe0d082 | 1019 | if (object == NULL || |
175f072e | 1020 | object->paging_in_progress != 0 || |
ffe0d082 | 1021 | object->pager != NULL) |
175f072e KM |
1022 | return; |
1023 | ||
1024 | /* | |
1025 | * There is a backing object, and | |
1026 | */ | |
1027 | ||
ffe0d082 | 1028 | if ((backing_object = object->shadow) == NULL) |
175f072e KM |
1029 | return; |
1030 | ||
1031 | vm_object_lock(backing_object); | |
1032 | /* | |
1033 | * ... | |
1034 | * The backing object is not read_only, | |
1035 | * and no pages in the backing object are | |
1036 | * currently being paged out. | |
1037 | * The backing object is internal. | |
1038 | */ | |
1039 | ||
d4ab8fb9 | 1040 | if ((backing_object->flags & OBJ_INTERNAL) == 0 || |
175f072e KM |
1041 | backing_object->paging_in_progress != 0) { |
1042 | vm_object_unlock(backing_object); | |
1043 | return; | |
1044 | } | |
1045 | ||
1046 | /* | |
1047 | * The backing object can't be a copy-object: | |
1048 | * the shadow_offset for the copy-object must stay | |
1049 | * as 0. Furthermore (for the 'we have all the | |
1050 | * pages' case), if we bypass backing_object and | |
1051 | * just shadow the next object in the chain, old | |
1052 | * pages from that object would then have to be copied | |
1053 | * BOTH into the (former) backing_object and into the | |
1054 | * parent object. | |
1055 | */ | |
ffe0d082 MK |
1056 | if (backing_object->shadow != NULL && |
1057 | backing_object->shadow->copy != NULL) { | |
175f072e KM |
1058 | vm_object_unlock(backing_object); |
1059 | return; | |
1060 | } | |
1061 | ||
1062 | /* | |
1063 | * We know that we can either collapse the backing | |
1064 | * object (if the parent is the only reference to | |
1065 | * it) or (perhaps) remove the parent's reference | |
1066 | * to it. | |
1067 | */ | |
1068 | ||
1069 | backing_offset = object->shadow_offset; | |
1070 | size = object->size; | |
1071 | ||
1072 | /* | |
1073 | * If there is exactly one reference to the backing | |
1074 | * object, we can collapse it into the parent. | |
1075 | */ | |
1076 | ||
1077 | if (backing_object->ref_count == 1) { | |
1078 | ||
1079 | /* | |
1080 | * We can collapse the backing object. | |
1081 | * | |
1082 | * Move all in-memory pages from backing_object | |
1083 | * to the parent. Pages that have been paged out | |
1084 | * will be overwritten by any of the parent's | |
1085 | * pages that shadow them. | |
1086 | */ | |
1087 | ||
4fee7222 | 1088 | while ((p = backing_object->memq.tqh_first) != NULL) { |
175f072e KM |
1089 | new_offset = (p->offset - backing_offset); |
1090 | ||
1091 | /* | |
1092 | * If the parent has a page here, or if | |
1093 | * this page falls outside the parent, | |
1094 | * dispose of it. | |
1095 | * | |
1096 | * Otherwise, move it as planned. | |
1097 | */ | |
1098 | ||
1099 | if (p->offset < backing_offset || | |
1100 | new_offset >= size) { | |
1101 | vm_page_lock_queues(); | |
1102 | vm_page_free(p); | |
1103 | vm_page_unlock_queues(); | |
1104 | } else { | |
1105 | pp = vm_page_lookup(object, new_offset); | |
2cbf9af3 | 1106 | if (pp != NULL && !(pp->flags & PG_FAKE)) { |
175f072e KM |
1107 | vm_page_lock_queues(); |
1108 | vm_page_free(p); | |
1109 | vm_page_unlock_queues(); | |
1110 | } | |
1111 | else { | |
1112 | if (pp) { | |
1113 | /* may be someone waiting for it */ | |
1114 | PAGE_WAKEUP(pp); | |
1115 | vm_page_lock_queues(); | |
1116 | vm_page_free(pp); | |
1117 | vm_page_unlock_queues(); | |
1118 | } | |
1119 | vm_page_rename(p, object, new_offset); | |
1120 | } | |
1121 | } | |
1122 | } | |
1123 | ||
1124 | /* | |
1125 | * Move the pager from backing_object to object. | |
1126 | * | |
1127 | * XXX We're only using part of the paging space | |
1128 | * for keeps now... we ought to discard the | |
1129 | * unused portion. | |
1130 | */ | |
1131 | ||
7300cb48 MH |
1132 | if (backing_object->pager) { |
1133 | object->pager = backing_object->pager; | |
1134 | object->paging_offset = backing_offset + | |
1135 | backing_object->paging_offset; | |
1136 | backing_object->pager = NULL; | |
1137 | } | |
175f072e KM |
1138 | |
1139 | /* | |
1140 | * Object now shadows whatever backing_object did. | |
1141 | * Note that the reference to backing_object->shadow | |
1142 | * moves from within backing_object to within object. | |
1143 | */ | |
1144 | ||
1145 | object->shadow = backing_object->shadow; | |
1146 | object->shadow_offset += backing_object->shadow_offset; | |
ffe0d082 MK |
1147 | if (object->shadow != NULL && |
1148 | object->shadow->copy != NULL) { | |
175f072e KM |
1149 | panic("vm_object_collapse: we collapsed a copy-object!"); |
1150 | } | |
1151 | /* | |
1152 | * Discard backing_object. | |
1153 | * | |
1154 | * Since the backing object has no pages, no | |
1155 | * pager left, and no object references within it, | |
1156 | * all that is necessary is to dispose of it. | |
1157 | */ | |
1158 | ||
1159 | vm_object_unlock(backing_object); | |
1160 | ||
1161 | simple_lock(&vm_object_list_lock); | |
4fee7222 KM |
1162 | TAILQ_REMOVE(&vm_object_list, backing_object, |
1163 | object_list); | |
175f072e KM |
1164 | vm_object_count--; |
1165 | simple_unlock(&vm_object_list_lock); | |
1166 | ||
1167 | free((caddr_t)backing_object, M_VMOBJ); | |
1168 | ||
1169 | object_collapses++; | |
1170 | } | |
1171 | else { | |
1172 | /* | |
1173 | * If all of the pages in the backing object are | |
1174 | * shadowed by the parent object, the parent | |
1175 | * object no longer has to shadow the backing | |
1176 | * object; it can shadow the next one in the | |
1177 | * chain. | |
1178 | * | |
1179 | * The backing object must not be paged out - we'd | |
1180 | * have to check all of the paged-out pages, as | |
1181 | * well. | |
1182 | */ | |
1183 | ||
ffe0d082 | 1184 | if (backing_object->pager != NULL) { |
175f072e KM |
1185 | vm_object_unlock(backing_object); |
1186 | return; | |
1187 | } | |
1188 | ||
1189 | /* | |
1190 | * Should have a check for a 'small' number | |
1191 | * of pages here. | |
1192 | */ | |
1193 | ||
4fee7222 KM |
1194 | for (p = backing_object->memq.tqh_first; |
1195 | p != NULL; | |
1196 | p = p->listq.tqe_next) { | |
175f072e KM |
1197 | new_offset = (p->offset - backing_offset); |
1198 | ||
1199 | /* | |
1200 | * If the parent has a page here, or if | |
1201 | * this page falls outside the parent, | |
1202 | * keep going. | |
1203 | * | |
1204 | * Otherwise, the backing_object must be | |
1205 | * left in the chain. | |
1206 | */ | |
1207 | ||
1208 | if (p->offset >= backing_offset && | |
7300cb48 | 1209 | new_offset < size && |
175f072e | 1210 | ((pp = vm_page_lookup(object, new_offset)) |
ffe0d082 | 1211 | == NULL || |
2cbf9af3 | 1212 | (pp->flags & PG_FAKE))) { |
175f072e KM |
1213 | /* |
1214 | * Page still needed. | |
1215 | * Can't go any further. | |
1216 | */ | |
1217 | vm_object_unlock(backing_object); | |
1218 | return; | |
1219 | } | |
175f072e KM |
1220 | } |
1221 | ||
1222 | /* | |
1223 | * Make the parent shadow the next object | |
1224 | * in the chain. Deallocating backing_object | |
1225 | * will not remove it, since its reference | |
1226 | * count is at least 2. | |
1227 | */ | |
1228 | ||
7300cb48 MH |
1229 | object->shadow = backing_object->shadow; |
1230 | vm_object_reference(object->shadow); | |
175f072e KM |
1231 | object->shadow_offset += backing_object->shadow_offset; |
1232 | ||
63cbdb1b MH |
1233 | /* |
1234 | * Backing object might have had a copy pointer | |
1235 | * to us. If it did, clear it. | |
1236 | */ | |
1237 | if (backing_object->copy == object) { | |
a8e21b89 | 1238 | backing_object->copy = NULL; |
63cbdb1b MH |
1239 | } |
1240 | ||
175f072e KM |
1241 | /* Drop the reference count on backing_object. |
1242 | * Since its ref_count was at least 2, it | |
1243 | * will not vanish; so we don't need to call | |
1244 | * vm_object_deallocate. | |
1245 | */ | |
1246 | backing_object->ref_count--; | |
1247 | vm_object_unlock(backing_object); | |
1248 | ||
1249 | object_bypasses ++; | |
1250 | ||
1251 | } | |
1252 | ||
1253 | /* | |
1254 | * Try again with this object's new backing object. | |
1255 | */ | |
1256 | } | |
1257 | } | |
1258 | ||
1259 | /* | |
1260 | * vm_object_page_remove: [internal] | |
1261 | * | |
1262 | * Removes all physical pages in the specified | |
1263 | * object range from the object's list of pages. | |
1264 | * | |
1265 | * The object must be locked. | |
1266 | */ | |
70b9635a CD |
1267 | void |
1268 | vm_object_page_remove(object, start, end) | |
175f072e KM |
1269 | register vm_object_t object; |
1270 | register vm_offset_t start; | |
1271 | register vm_offset_t end; | |
1272 | { | |
1273 | register vm_page_t p, next; | |
1274 | ||
ffe0d082 | 1275 | if (object == NULL) |
175f072e KM |
1276 | return; |
1277 | ||
4fee7222 KM |
1278 | for (p = object->memq.tqh_first; p != NULL; p = next) { |
1279 | next = p->listq.tqe_next; | |
175f072e | 1280 | if ((start <= p->offset) && (p->offset < end)) { |
ae1e5b95 | 1281 | pmap_page_protect(VM_PAGE_TO_PHYS(p), VM_PROT_NONE); |
175f072e KM |
1282 | vm_page_lock_queues(); |
1283 | vm_page_free(p); | |
1284 | vm_page_unlock_queues(); | |
1285 | } | |
175f072e KM |
1286 | } |
1287 | } | |
1288 | ||
1289 | /* | |
1290 | * Routine: vm_object_coalesce | |
1291 | * Function: Coalesces two objects backing up adjoining | |
1292 | * regions of memory into a single object. | |
1293 | * | |
1294 | * returns TRUE if objects were combined. | |
1295 | * | |
1296 | * NOTE: Only works at the moment if the second object is NULL - | |
1297 | * if it's not, which object do we lock first? | |
1298 | * | |
1299 | * Parameters: | |
1300 | * prev_object First object to coalesce | |
1301 | * prev_offset Offset into prev_object | |
1302 | * next_object Second object into coalesce | |
1303 | * next_offset Offset into next_object | |
1304 | * | |
1305 | * prev_size Size of reference to prev_object | |
1306 | * next_size Size of reference to next_object | |
1307 | * | |
1308 | * Conditions: | |
1309 | * The object must *not* be locked. | |
1310 | */ | |
70b9635a CD |
1311 | boolean_t |
1312 | vm_object_coalesce(prev_object, next_object, | |
175f072e KM |
1313 | prev_offset, next_offset, |
1314 | prev_size, next_size) | |
1315 | ||
1316 | register vm_object_t prev_object; | |
1317 | vm_object_t next_object; | |
1318 | vm_offset_t prev_offset, next_offset; | |
1319 | vm_size_t prev_size, next_size; | |
1320 | { | |
1321 | vm_size_t newsize; | |
1322 | ||
1323 | #ifdef lint | |
1324 | next_offset++; | |
1524bcb8 | 1325 | #endif |
175f072e | 1326 | |
ffe0d082 | 1327 | if (next_object != NULL) { |
175f072e KM |
1328 | return(FALSE); |
1329 | } | |
1330 | ||
ffe0d082 | 1331 | if (prev_object == NULL) { |
175f072e KM |
1332 | return(TRUE); |
1333 | } | |
1334 | ||
1335 | vm_object_lock(prev_object); | |
1336 | ||
1337 | /* | |
1338 | * Try to collapse the object first | |
1339 | */ | |
1340 | vm_object_collapse(prev_object); | |
1341 | ||
1342 | /* | |
1343 | * Can't coalesce if: | |
1344 | * . more than one reference | |
1345 | * . paged out | |
1346 | * . shadows another object | |
1347 | * . has a copy elsewhere | |
1348 | * (any of which mean that the pages not mapped to | |
1349 | * prev_entry may be in use anyway) | |
1350 | */ | |
1351 | ||
1352 | if (prev_object->ref_count > 1 || | |
ffe0d082 MK |
1353 | prev_object->pager != NULL || |
1354 | prev_object->shadow != NULL || | |
1355 | prev_object->copy != NULL) { | |
175f072e KM |
1356 | vm_object_unlock(prev_object); |
1357 | return(FALSE); | |
1358 | } | |
1359 | ||
1360 | /* | |
1361 | * Remove any pages that may still be in the object from | |
1362 | * a previous deallocation. | |
1363 | */ | |
1364 | ||
1365 | vm_object_page_remove(prev_object, | |
1366 | prev_offset + prev_size, | |
1367 | prev_offset + prev_size + next_size); | |
1368 | ||
1369 | /* | |
1370 | * Extend the object if necessary. | |
1371 | */ | |
1372 | newsize = prev_offset + prev_size + next_size; | |
1373 | if (newsize > prev_object->size) | |
1374 | prev_object->size = newsize; | |
1375 | ||
1376 | vm_object_unlock(prev_object); | |
1377 | return(TRUE); | |
1378 | } | |
1379 | ||
1380 | /* | |
1381 | * vm_object_print: [ debug ] | |
1382 | */ | |
70b9635a CD |
1383 | void |
1384 | vm_object_print(object, full) | |
175f072e KM |
1385 | vm_object_t object; |
1386 | boolean_t full; | |
1387 | { | |
1388 | register vm_page_t p; | |
1389 | extern indent; | |
1390 | ||
1391 | register int count; | |
1392 | ||
ffe0d082 | 1393 | if (object == NULL) |
175f072e KM |
1394 | return; |
1395 | ||
1396 | iprintf("Object 0x%x: size=0x%x, res=%d, ref=%d, ", | |
1397 | (int) object, (int) object->size, | |
1398 | object->resident_page_count, object->ref_count); | |
1399 | printf("pager=0x%x+0x%x, shadow=(0x%x)+0x%x\n", | |
1400 | (int) object->pager, (int) object->paging_offset, | |
1401 | (int) object->shadow, (int) object->shadow_offset); | |
1402 | printf("cache: next=0x%x, prev=0x%x\n", | |
4fee7222 | 1403 | object->cached_list.tqe_next, object->cached_list.tqe_prev); |
175f072e KM |
1404 | |
1405 | if (!full) | |
1406 | return; | |
1407 | ||
1408 | indent += 2; | |
1409 | count = 0; | |
4fee7222 | 1410 | for (p = object->memq.tqh_first; p != NULL; p = p->listq.tqe_next) { |
175f072e KM |
1411 | if (count == 0) |
1412 | iprintf("memory:="); | |
1413 | else if (count == 6) { | |
1414 | printf("\n"); | |
1415 | iprintf(" ..."); | |
1416 | count = 0; | |
1417 | } else | |
1418 | printf(","); | |
1419 | count++; | |
1420 | ||
1421 | printf("(off=0x%x,page=0x%x)", p->offset, VM_PAGE_TO_PHYS(p)); | |
175f072e KM |
1422 | } |
1423 | if (count != 0) | |
1424 | printf("\n"); | |
1425 | indent -= 2; | |
1426 | } |