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15637ed4 RG |
1 | /* |
2 | * Copyright (c) 1991 Regents of the University of California. | |
3 | * All rights reserved. | |
4 | * | |
5 | * This code is derived from software contributed to Berkeley by | |
6 | * The Mach Operating System project at Carnegie-Mellon University. | |
7 | * | |
8 | * Redistribution and use in source and binary forms, with or without | |
9 | * modification, are permitted provided that the following conditions | |
10 | * are met: | |
11 | * 1. Redistributions of source code must retain the above copyright | |
12 | * notice, this list of conditions and the following disclaimer. | |
13 | * 2. Redistributions in binary form must reproduce the above copyright | |
14 | * notice, this list of conditions and the following disclaimer in the | |
15 | * documentation and/or other materials provided with the distribution. | |
16 | * 3. All advertising materials mentioning features or use of this software | |
17 | * must display the following acknowledgement: | |
18 | * This product includes software developed by the University of | |
19 | * California, Berkeley and its contributors. | |
20 | * 4. Neither the name of the University nor the names of its contributors | |
21 | * may be used to endorse or promote products derived from this software | |
22 | * without specific prior written permission. | |
23 | * | |
24 | * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND | |
25 | * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE | |
26 | * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE | |
27 | * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE | |
28 | * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL | |
29 | * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS | |
30 | * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) | |
31 | * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT | |
32 | * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY | |
33 | * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF | |
34 | * SUCH DAMAGE. | |
35 | * | |
1284e777 | 36 | * from: @(#)vm_object.c 7.4 (Berkeley) 5/7/91 |
fde1aeb2 | 37 | * $Id: vm_object.c,v 1.10 1993/11/25 12:07:41 davidg Exp $ |
1284e777 RG |
38 | */ |
39 | ||
40 | /* | |
15637ed4 RG |
41 | * Copyright (c) 1987, 1990 Carnegie-Mellon University. |
42 | * All rights reserved. | |
43 | * | |
44 | * Authors: Avadis Tevanian, Jr., Michael Wayne Young | |
45 | * | |
46 | * Permission to use, copy, modify and distribute this software and | |
47 | * its documentation is hereby granted, provided that both the copyright | |
48 | * notice and this permission notice appear in all copies of the | |
49 | * software, derivative works or modified versions, and any portions | |
50 | * thereof, and that both notices appear in supporting documentation. | |
51 | * | |
52 | * CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS" | |
53 | * CONDITION. CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND | |
54 | * FOR ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE. | |
55 | * | |
56 | * Carnegie Mellon requests users of this software to return to | |
57 | * | |
58 | * Software Distribution Coordinator or Software.Distribution@CS.CMU.EDU | |
59 | * School of Computer Science | |
60 | * Carnegie Mellon University | |
61 | * Pittsburgh PA 15213-3890 | |
62 | * | |
63 | * any improvements or extensions that they make and grant Carnegie the | |
64 | * rights to redistribute these changes. | |
15637ed4 RG |
65 | */ |
66 | ||
67 | /* | |
68 | * Virtual memory object module. | |
69 | */ | |
70 | ||
71 | #include "param.h" | |
fde1aeb2 | 72 | #include "systm.h" |
15637ed4 RG |
73 | #include "malloc.h" |
74 | ||
75 | #include "vm.h" | |
76 | #include "vm_page.h" | |
fde1aeb2 GW |
77 | #include "ddb.h" |
78 | ||
15637ed4 | 79 | |
4c45483e GW |
80 | static void _vm_object_allocate(vm_size_t, vm_object_t); |
81 | static void vm_object_deactivate_pages(vm_object_t); | |
82 | static void vm_object_cache_trim(void); | |
83 | static void vm_object_remove(vm_pager_t); | |
84 | ||
15637ed4 RG |
85 | /* |
86 | * Virtual memory objects maintain the actual data | |
87 | * associated with allocated virtual memory. A given | |
88 | * page of memory exists within exactly one object. | |
89 | * | |
90 | * An object is only deallocated when all "references" | |
91 | * are given up. Only one "reference" to a given | |
92 | * region of an object should be writeable. | |
93 | * | |
94 | * Associated with each object is a list of all resident | |
95 | * memory pages belonging to that object; this list is | |
96 | * maintained by the "vm_page" module, and locked by the object's | |
97 | * lock. | |
98 | * | |
99 | * Each object also records a "pager" routine which is | |
100 | * used to retrieve (and store) pages to the proper backing | |
101 | * storage. In addition, objects may be backed by other | |
102 | * objects from which they were virtual-copied. | |
103 | * | |
104 | * The only items within the object structure which are | |
105 | * modified after time of creation are: | |
106 | * reference count locked by object's lock | |
107 | * pager routine locked by object's lock | |
108 | * | |
109 | */ | |
110 | ||
bbc3f849 GW |
111 | queue_head_t vm_object_cached_list; /* list of objects persisting */ |
112 | int vm_object_cached; /* size of cached list */ | |
113 | simple_lock_data_t vm_cache_lock; /* lock for object cache */ | |
114 | ||
115 | queue_head_t vm_object_list; /* list of allocated objects */ | |
116 | long vm_object_count; /* count of all objects */ | |
117 | simple_lock_data_t vm_object_list_lock; | |
118 | /* lock for object list and count */ | |
119 | ||
120 | vm_object_t kernel_object; /* the single kernel object */ | |
121 | vm_object_t kmem_object; | |
122 | ||
15637ed4 RG |
123 | struct vm_object kernel_object_store; |
124 | struct vm_object kmem_object_store; | |
125 | ||
126 | #define VM_OBJECT_HASH_COUNT 157 | |
127 | ||
128 | int vm_cache_max = 100; /* can patch if necessary */ | |
129 | queue_head_t vm_object_hashtable[VM_OBJECT_HASH_COUNT]; | |
130 | ||
131 | long object_collapses = 0; | |
132 | long object_bypasses = 0; | |
133 | ||
134 | /* | |
135 | * vm_object_init: | |
136 | * | |
137 | * Initialize the VM objects module. | |
138 | */ | |
139 | void vm_object_init() | |
140 | { | |
141 | register int i; | |
142 | ||
143 | queue_init(&vm_object_cached_list); | |
144 | queue_init(&vm_object_list); | |
145 | vm_object_count = 0; | |
146 | simple_lock_init(&vm_cache_lock); | |
147 | simple_lock_init(&vm_object_list_lock); | |
148 | ||
149 | for (i = 0; i < VM_OBJECT_HASH_COUNT; i++) | |
150 | queue_init(&vm_object_hashtable[i]); | |
151 | ||
152 | kernel_object = &kernel_object_store; | |
153 | _vm_object_allocate(VM_MAX_KERNEL_ADDRESS - VM_MIN_KERNEL_ADDRESS, | |
154 | kernel_object); | |
155 | ||
156 | kmem_object = &kmem_object_store; | |
157 | _vm_object_allocate(VM_KMEM_SIZE + VM_MBUF_SIZE, kmem_object); | |
158 | } | |
159 | ||
160 | /* | |
161 | * vm_object_allocate: | |
162 | * | |
163 | * Returns a new object with the given size. | |
164 | */ | |
165 | ||
166 | vm_object_t vm_object_allocate(size) | |
167 | vm_size_t size; | |
168 | { | |
169 | register vm_object_t result; | |
170 | ||
171 | result = (vm_object_t) | |
172 | malloc((u_long)sizeof *result, M_VMOBJ, M_WAITOK); | |
173 | ||
174 | _vm_object_allocate(size, result); | |
175 | ||
176 | return(result); | |
177 | } | |
178 | ||
4c45483e | 179 | static void |
15637ed4 RG |
180 | _vm_object_allocate(size, object) |
181 | vm_size_t size; | |
182 | register vm_object_t object; | |
183 | { | |
184 | queue_init(&object->memq); | |
185 | vm_object_lock_init(object); | |
186 | object->ref_count = 1; | |
187 | object->resident_page_count = 0; | |
188 | object->size = size; | |
189 | object->can_persist = FALSE; | |
190 | object->paging_in_progress = 0; | |
191 | object->copy = NULL; | |
192 | ||
193 | /* | |
194 | * Object starts out read-write, with no pager. | |
195 | */ | |
196 | ||
197 | object->pager = NULL; | |
198 | object->pager_ready = FALSE; | |
199 | object->internal = TRUE; /* vm_allocate_with_pager will reset */ | |
200 | object->paging_offset = 0; | |
201 | object->shadow = NULL; | |
202 | object->shadow_offset = (vm_offset_t) 0; | |
203 | ||
204 | simple_lock(&vm_object_list_lock); | |
205 | queue_enter(&vm_object_list, object, vm_object_t, object_list); | |
206 | vm_object_count++; | |
207 | simple_unlock(&vm_object_list_lock); | |
208 | } | |
209 | ||
210 | /* | |
211 | * vm_object_reference: | |
212 | * | |
213 | * Gets another reference to the given object. | |
214 | */ | |
215 | void vm_object_reference(object) | |
216 | register vm_object_t object; | |
217 | { | |
218 | if (object == NULL) | |
219 | return; | |
220 | ||
221 | vm_object_lock(object); | |
222 | object->ref_count++; | |
223 | vm_object_unlock(object); | |
224 | } | |
225 | ||
226 | /* | |
227 | * vm_object_deallocate: | |
228 | * | |
229 | * Release a reference to the specified object, | |
230 | * gained either through a vm_object_allocate | |
231 | * or a vm_object_reference call. When all references | |
232 | * are gone, storage associated with this object | |
233 | * may be relinquished. | |
234 | * | |
235 | * No object may be locked. | |
236 | */ | |
237 | void vm_object_deallocate(object) | |
238 | register vm_object_t object; | |
239 | { | |
240 | vm_object_t temp; | |
241 | ||
242 | while (object != NULL) { | |
243 | ||
244 | /* | |
245 | * The cache holds a reference (uncounted) to | |
246 | * the object; we must lock it before removing | |
247 | * the object. | |
248 | */ | |
249 | ||
250 | vm_object_cache_lock(); | |
251 | ||
252 | /* | |
253 | * Lose the reference | |
254 | */ | |
255 | vm_object_lock(object); | |
256 | if (--(object->ref_count) != 0) { | |
257 | ||
258 | /* | |
259 | * If there are still references, then | |
260 | * we are done. | |
261 | */ | |
262 | vm_object_unlock(object); | |
263 | vm_object_cache_unlock(); | |
264 | return; | |
265 | } | |
266 | ||
267 | /* | |
268 | * See if this object can persist. If so, enter | |
269 | * it in the cache, then deactivate all of its | |
270 | * pages. | |
271 | */ | |
272 | ||
273 | if (object->can_persist) { | |
3ad802c6 | 274 | #ifdef DIAGNOSTIC |
15637ed4 RG |
275 | register vm_page_t p; |
276 | ||
277 | /* | |
278 | * Check for dirty pages in object | |
279 | * Print warning as this may signify kernel bugs | |
280 | * pk@cs.few.eur.nl - 4/15/93 | |
281 | */ | |
282 | p = (vm_page_t) queue_first(&object->memq); | |
283 | while (!queue_end(&object->memq, (queue_entry_t) p)) { | |
284 | VM_PAGE_CHECK(p); | |
285 | ||
286 | if (pmap_is_modified(VM_PAGE_TO_PHYS(p)) || | |
287 | !p->clean) { | |
288 | ||
289 | printf("vm_object_dealloc: persistent object %x isn't clean\n", object); | |
290 | goto cant_persist; | |
291 | } | |
292 | ||
293 | p = (vm_page_t) queue_next(&p->listq); | |
294 | } | |
3ad802c6 | 295 | #endif /* DIAGNOSTIC */ |
15637ed4 RG |
296 | |
297 | queue_enter(&vm_object_cached_list, object, | |
298 | vm_object_t, cached_list); | |
299 | vm_object_cached++; | |
300 | vm_object_cache_unlock(); | |
301 | ||
302 | vm_object_deactivate_pages(object); | |
303 | vm_object_unlock(object); | |
304 | ||
305 | vm_object_cache_trim(); | |
306 | return; | |
307 | } | |
308 | cant_persist:; | |
309 | ||
310 | /* | |
311 | * Make sure no one can look us up now. | |
312 | */ | |
313 | vm_object_remove(object->pager); | |
314 | vm_object_cache_unlock(); | |
315 | ||
316 | temp = object->shadow; | |
317 | vm_object_terminate(object); | |
318 | /* unlocks and deallocates object */ | |
319 | object = temp; | |
320 | } | |
321 | } | |
322 | ||
323 | ||
324 | /* | |
325 | * vm_object_terminate actually destroys the specified object, freeing | |
326 | * up all previously used resources. | |
327 | * | |
328 | * The object must be locked. | |
329 | */ | |
330 | void vm_object_terminate(object) | |
331 | register vm_object_t object; | |
332 | { | |
333 | register vm_page_t p; | |
334 | vm_object_t shadow_object; | |
335 | ||
336 | /* | |
337 | * Detach the object from its shadow if we are the shadow's | |
338 | * copy. | |
339 | */ | |
340 | if ((shadow_object = object->shadow) != NULL) { | |
341 | vm_object_lock(shadow_object); | |
342 | if (shadow_object->copy == object) | |
343 | shadow_object->copy = NULL; | |
344 | #if 0 | |
345 | else if (shadow_object->copy != NULL) | |
346 | panic("vm_object_terminate: copy/shadow inconsistency"); | |
347 | #endif | |
348 | vm_object_unlock(shadow_object); | |
349 | } | |
350 | ||
351 | /* | |
352 | * Wait until the pageout daemon is through | |
353 | * with the object. | |
354 | */ | |
355 | ||
356 | while (object->paging_in_progress != 0) { | |
4c45483e | 357 | vm_object_sleep((int)object, object, FALSE); |
15637ed4 RG |
358 | vm_object_lock(object); |
359 | } | |
360 | ||
361 | ||
362 | /* | |
363 | * While the paging system is locked, | |
364 | * pull the object's pages off the active | |
365 | * and inactive queues. This keeps the | |
366 | * pageout daemon from playing with them | |
367 | * during vm_pager_deallocate. | |
368 | * | |
369 | * We can't free the pages yet, because the | |
370 | * object's pager may have to write them out | |
371 | * before deallocating the paging space. | |
372 | */ | |
373 | ||
374 | p = (vm_page_t) queue_first(&object->memq); | |
375 | while (!queue_end(&object->memq, (queue_entry_t) p)) { | |
376 | VM_PAGE_CHECK(p); | |
377 | ||
378 | vm_page_lock_queues(); | |
379 | if (p->active) { | |
380 | queue_remove(&vm_page_queue_active, p, vm_page_t, | |
381 | pageq); | |
382 | p->active = FALSE; | |
383 | vm_page_active_count--; | |
384 | } | |
385 | ||
386 | if (p->inactive) { | |
387 | queue_remove(&vm_page_queue_inactive, p, vm_page_t, | |
388 | pageq); | |
389 | p->inactive = FALSE; | |
390 | vm_page_inactive_count--; | |
391 | } | |
392 | vm_page_unlock_queues(); | |
393 | p = (vm_page_t) queue_next(&p->listq); | |
394 | } | |
395 | ||
396 | vm_object_unlock(object); | |
397 | ||
398 | if (object->paging_in_progress != 0) | |
399 | panic("vm_object_deallocate: pageout in progress"); | |
400 | ||
401 | /* | |
402 | * Clean and free the pages, as appropriate. | |
403 | * All references to the object are gone, | |
404 | * so we don't need to lock it. | |
405 | */ | |
406 | ||
407 | if (!object->internal) { | |
408 | vm_object_lock(object); | |
409 | vm_object_page_clean(object, 0, 0); | |
410 | vm_object_unlock(object); | |
411 | } | |
412 | while (!queue_empty(&object->memq)) { | |
413 | p = (vm_page_t) queue_first(&object->memq); | |
414 | ||
415 | VM_PAGE_CHECK(p); | |
416 | ||
417 | vm_page_lock_queues(); | |
418 | vm_page_free(p); | |
419 | vm_page_unlock_queues(); | |
420 | } | |
421 | ||
422 | /* | |
423 | * Let the pager know object is dead. | |
424 | */ | |
425 | ||
426 | if (object->pager != NULL) | |
427 | vm_pager_deallocate(object->pager); | |
428 | ||
429 | ||
430 | simple_lock(&vm_object_list_lock); | |
431 | queue_remove(&vm_object_list, object, vm_object_t, object_list); | |
432 | vm_object_count--; | |
433 | simple_unlock(&vm_object_list_lock); | |
434 | ||
435 | /* | |
436 | * Free the space for the object. | |
437 | */ | |
438 | ||
439 | free((caddr_t)object, M_VMOBJ); | |
440 | } | |
441 | ||
442 | /* | |
443 | * vm_object_page_clean | |
444 | * | |
445 | * Clean all dirty pages in the specified range of object. | |
446 | * Leaves page on whatever queue it is currently on. | |
447 | * | |
448 | * Odd semantics: if start == end, we clean everything. | |
449 | * | |
450 | * The object must be locked. | |
451 | */ | |
4c45483e | 452 | void |
15637ed4 RG |
453 | vm_object_page_clean(object, start, end) |
454 | register vm_object_t object; | |
455 | register vm_offset_t start; | |
456 | register vm_offset_t end; | |
457 | { | |
458 | register vm_page_t p; | |
459 | ||
460 | if (object->pager == NULL) | |
461 | return; | |
462 | ||
463 | again: | |
464 | p = (vm_page_t) queue_first(&object->memq); | |
465 | while (!queue_end(&object->memq, (queue_entry_t) p)) { | |
466 | if (start == end || | |
467 | p->offset >= start && p->offset < end) { | |
468 | if (p->clean && pmap_is_modified(VM_PAGE_TO_PHYS(p))) | |
469 | p->clean = FALSE; | |
470 | pmap_page_protect(VM_PAGE_TO_PHYS(p), VM_PROT_NONE); | |
471 | if (!p->clean) { | |
472 | p->busy = TRUE; | |
473 | object->paging_in_progress++; | |
474 | vm_object_unlock(object); | |
475 | (void) vm_pager_put(object->pager, p, TRUE); | |
476 | vm_object_lock(object); | |
477 | object->paging_in_progress--; | |
478 | p->busy = FALSE; | |
479 | PAGE_WAKEUP(p); | |
480 | goto again; | |
481 | } | |
482 | } | |
483 | p = (vm_page_t) queue_next(&p->listq); | |
484 | } | |
485 | } | |
486 | ||
487 | /* | |
488 | * vm_object_deactivate_pages | |
489 | * | |
490 | * Deactivate all pages in the specified object. (Keep its pages | |
491 | * in memory even though it is no longer referenced.) | |
492 | * | |
493 | * The object must be locked. | |
494 | */ | |
4c45483e | 495 | static void |
15637ed4 RG |
496 | vm_object_deactivate_pages(object) |
497 | register vm_object_t object; | |
498 | { | |
499 | register vm_page_t p, next; | |
500 | ||
501 | p = (vm_page_t) queue_first(&object->memq); | |
502 | while (!queue_end(&object->memq, (queue_entry_t) p)) { | |
503 | next = (vm_page_t) queue_next(&p->listq); | |
504 | vm_page_lock_queues(); | |
8820571b NW |
505 | if (!p->busy) |
506 | vm_page_deactivate(p); /* optimisation from mach 3.0 - | |
507 | * andrew@werple.apana.org.au, | |
508 | * Feb '93 | |
509 | */ | |
15637ed4 RG |
510 | vm_page_unlock_queues(); |
511 | p = next; | |
512 | } | |
513 | } | |
514 | ||
515 | /* | |
516 | * Trim the object cache to size. | |
517 | */ | |
4c45483e | 518 | static void |
15637ed4 RG |
519 | vm_object_cache_trim() |
520 | { | |
521 | register vm_object_t object; | |
522 | ||
523 | vm_object_cache_lock(); | |
524 | while (vm_object_cached > vm_cache_max) { | |
525 | object = (vm_object_t) queue_first(&vm_object_cached_list); | |
526 | vm_object_cache_unlock(); | |
527 | ||
528 | if (object != vm_object_lookup(object->pager)) | |
529 | panic("vm_object_deactivate: I'm sooo confused."); | |
530 | ||
531 | pager_cache(object, FALSE); | |
532 | ||
533 | vm_object_cache_lock(); | |
534 | } | |
535 | vm_object_cache_unlock(); | |
536 | } | |
537 | ||
538 | ||
539 | /* | |
540 | * vm_object_shutdown() | |
541 | * | |
542 | * Shut down the object system. Unfortunately, while we | |
543 | * may be trying to do this, init is happily waiting for | |
544 | * processes to exit, and therefore will be causing some objects | |
545 | * to be deallocated. To handle this, we gain a fake reference | |
546 | * to all objects we release paging areas for. This will prevent | |
547 | * a duplicate deallocation. This routine is probably full of | |
548 | * race conditions! | |
549 | */ | |
550 | ||
551 | void vm_object_shutdown() | |
552 | { | |
553 | register vm_object_t object; | |
554 | ||
555 | /* | |
556 | * Clean up the object cache *before* we screw up the reference | |
557 | * counts on all of the objects. | |
558 | */ | |
559 | ||
560 | vm_object_cache_clear(); | |
561 | ||
562 | printf("free paging spaces: "); | |
563 | ||
564 | /* | |
565 | * First we gain a reference to each object so that | |
566 | * no one else will deallocate them. | |
567 | */ | |
568 | ||
569 | simple_lock(&vm_object_list_lock); | |
570 | object = (vm_object_t) queue_first(&vm_object_list); | |
571 | while (!queue_end(&vm_object_list, (queue_entry_t) object)) { | |
572 | vm_object_reference(object); | |
573 | object = (vm_object_t) queue_next(&object->object_list); | |
574 | } | |
575 | simple_unlock(&vm_object_list_lock); | |
576 | ||
577 | /* | |
578 | * Now we deallocate all the paging areas. We don't need | |
579 | * to lock anything because we've reduced to a single | |
580 | * processor while shutting down. This also assumes that | |
581 | * no new objects are being created. | |
582 | */ | |
583 | ||
584 | object = (vm_object_t) queue_first(&vm_object_list); | |
585 | while (!queue_end(&vm_object_list, (queue_entry_t) object)) { | |
586 | if (object->pager != NULL) | |
587 | vm_pager_deallocate(object->pager); | |
588 | object = (vm_object_t) queue_next(&object->object_list); | |
589 | printf("."); | |
590 | } | |
591 | printf("done.\n"); | |
592 | } | |
593 | ||
594 | /* | |
595 | * vm_object_pmap_copy: | |
596 | * | |
597 | * Makes all physical pages in the specified | |
598 | * object range copy-on-write. No writeable | |
599 | * references to these pages should remain. | |
600 | * | |
601 | * The object must *not* be locked. | |
602 | */ | |
603 | void vm_object_pmap_copy(object, start, end) | |
604 | register vm_object_t object; | |
605 | register vm_offset_t start; | |
606 | register vm_offset_t end; | |
607 | { | |
608 | register vm_page_t p; | |
609 | ||
610 | if (object == NULL) | |
611 | return; | |
612 | ||
613 | vm_object_lock(object); | |
614 | p = (vm_page_t) queue_first(&object->memq); | |
615 | while (!queue_end(&object->memq, (queue_entry_t) p)) { | |
616 | if ((start <= p->offset) && (p->offset < end)) { | |
617 | pmap_page_protect(VM_PAGE_TO_PHYS(p), VM_PROT_READ); | |
618 | p->copy_on_write = TRUE; | |
619 | } | |
620 | p = (vm_page_t) queue_next(&p->listq); | |
621 | } | |
622 | vm_object_unlock(object); | |
623 | } | |
624 | ||
625 | /* | |
626 | * vm_object_pmap_remove: | |
627 | * | |
628 | * Removes all physical pages in the specified | |
629 | * object range from all physical maps. | |
630 | * | |
631 | * The object must *not* be locked. | |
632 | */ | |
633 | void vm_object_pmap_remove(object, start, end) | |
634 | register vm_object_t object; | |
635 | register vm_offset_t start; | |
636 | register vm_offset_t end; | |
637 | { | |
638 | register vm_page_t p; | |
639 | ||
640 | if (object == NULL) | |
641 | return; | |
642 | ||
643 | vm_object_lock(object); | |
644 | p = (vm_page_t) queue_first(&object->memq); | |
645 | while (!queue_end(&object->memq, (queue_entry_t) p)) { | |
646 | if ((start <= p->offset) && (p->offset < end)) | |
647 | pmap_page_protect(VM_PAGE_TO_PHYS(p), VM_PROT_NONE); | |
648 | p = (vm_page_t) queue_next(&p->listq); | |
649 | } | |
650 | vm_object_unlock(object); | |
651 | } | |
652 | ||
653 | /* | |
654 | * vm_object_copy: | |
655 | * | |
656 | * Create a new object which is a copy of an existing | |
657 | * object, and mark all of the pages in the existing | |
658 | * object 'copy-on-write'. The new object has one reference. | |
659 | * Returns the new object. | |
660 | * | |
661 | * May defer the copy until later if the object is not backed | |
662 | * up by a non-default pager. | |
663 | */ | |
664 | void vm_object_copy(src_object, src_offset, size, | |
665 | dst_object, dst_offset, src_needs_copy) | |
666 | register vm_object_t src_object; | |
667 | vm_offset_t src_offset; | |
668 | vm_size_t size; | |
669 | vm_object_t *dst_object; /* OUT */ | |
670 | vm_offset_t *dst_offset; /* OUT */ | |
671 | boolean_t *src_needs_copy; /* OUT */ | |
672 | { | |
673 | register vm_object_t new_copy; | |
674 | register vm_object_t old_copy; | |
675 | vm_offset_t new_start, new_end; | |
676 | ||
677 | register vm_page_t p; | |
678 | ||
679 | if (src_object == NULL) { | |
680 | /* | |
681 | * Nothing to copy | |
682 | */ | |
683 | *dst_object = NULL; | |
684 | *dst_offset = 0; | |
685 | *src_needs_copy = FALSE; | |
686 | return; | |
687 | } | |
688 | ||
689 | /* | |
690 | * If the object's pager is null_pager or the | |
691 | * default pager, we don't have to make a copy | |
692 | * of it. Instead, we set the needs copy flag and | |
693 | * make a shadow later. | |
694 | */ | |
695 | ||
696 | vm_object_lock(src_object); | |
45852188 DG |
697 | |
698 | /* | |
699 | * we can simply add a reference to the object if we have no | |
700 | * pager or are using the swap pager or we have an internal object | |
701 | * | |
702 | * John Dyson 24 Nov 93 | |
703 | */ | |
15637ed4 | 704 | if (src_object->pager == NULL || |
45852188 DG |
705 | (src_object->pager->pg_type == PG_SWAP) || |
706 | src_object->internal) { | |
15637ed4 RG |
707 | |
708 | /* | |
709 | * Make another reference to the object | |
710 | */ | |
711 | src_object->ref_count++; | |
712 | ||
713 | /* | |
714 | * Mark all of the pages copy-on-write. | |
715 | */ | |
716 | for (p = (vm_page_t) queue_first(&src_object->memq); | |
717 | !queue_end(&src_object->memq, (queue_entry_t)p); | |
718 | p = (vm_page_t) queue_next(&p->listq)) { | |
719 | if (src_offset <= p->offset && | |
720 | p->offset < src_offset + size) | |
721 | p->copy_on_write = TRUE; | |
722 | } | |
723 | vm_object_unlock(src_object); | |
724 | ||
725 | *dst_object = src_object; | |
726 | *dst_offset = src_offset; | |
727 | ||
728 | /* | |
729 | * Must make a shadow when write is desired | |
730 | */ | |
731 | *src_needs_copy = TRUE; | |
732 | return; | |
733 | } | |
734 | ||
735 | /* | |
736 | * Try to collapse the object before copying it. | |
737 | */ | |
738 | vm_object_collapse(src_object); | |
739 | ||
740 | /* | |
741 | * If the object has a pager, the pager wants to | |
742 | * see all of the changes. We need a copy-object | |
743 | * for the changed pages. | |
744 | * | |
745 | * If there is a copy-object, and it is empty, | |
746 | * no changes have been made to the object since the | |
747 | * copy-object was made. We can use the same copy- | |
748 | * object. | |
749 | */ | |
750 | ||
751 | Retry1: | |
752 | old_copy = src_object->copy; | |
753 | if (old_copy != NULL) { | |
754 | /* | |
755 | * Try to get the locks (out of order) | |
756 | */ | |
757 | if (!vm_object_lock_try(old_copy)) { | |
758 | vm_object_unlock(src_object); | |
759 | ||
760 | /* should spin a bit here... */ | |
761 | vm_object_lock(src_object); | |
762 | goto Retry1; | |
763 | } | |
764 | ||
765 | if (old_copy->resident_page_count == 0 && | |
766 | old_copy->pager == NULL) { | |
767 | /* | |
768 | * Return another reference to | |
769 | * the existing copy-object. | |
770 | */ | |
771 | old_copy->ref_count++; | |
772 | vm_object_unlock(old_copy); | |
773 | vm_object_unlock(src_object); | |
774 | *dst_object = old_copy; | |
775 | *dst_offset = src_offset; | |
776 | *src_needs_copy = FALSE; | |
777 | return; | |
778 | } | |
779 | vm_object_unlock(old_copy); | |
780 | } | |
781 | vm_object_unlock(src_object); | |
782 | ||
783 | /* | |
784 | * If the object has a pager, the pager wants | |
785 | * to see all of the changes. We must make | |
786 | * a copy-object and put the changed pages there. | |
787 | * | |
788 | * The copy-object is always made large enough to | |
789 | * completely shadow the original object, since | |
790 | * it may have several users who want to shadow | |
791 | * the original object at different points. | |
792 | */ | |
793 | ||
794 | new_copy = vm_object_allocate(src_object->size); | |
795 | ||
796 | Retry2: | |
797 | vm_object_lock(src_object); | |
798 | /* | |
799 | * Copy object may have changed while we were unlocked | |
800 | */ | |
801 | old_copy = src_object->copy; | |
802 | if (old_copy != NULL) { | |
803 | /* | |
804 | * Try to get the locks (out of order) | |
805 | */ | |
806 | if (!vm_object_lock_try(old_copy)) { | |
807 | vm_object_unlock(src_object); | |
808 | goto Retry2; | |
809 | } | |
810 | ||
811 | /* | |
812 | * Consistency check | |
813 | */ | |
814 | if (old_copy->shadow != src_object || | |
815 | old_copy->shadow_offset != (vm_offset_t) 0) | |
816 | panic("vm_object_copy: copy/shadow inconsistency"); | |
817 | ||
818 | /* | |
819 | * Make the old copy-object shadow the new one. | |
820 | * It will receive no more pages from the original | |
821 | * object. | |
822 | */ | |
823 | ||
824 | src_object->ref_count--; /* remove ref. from old_copy */ | |
825 | old_copy->shadow = new_copy; | |
826 | new_copy->ref_count++; /* locking not needed - we | |
827 | have the only pointer */ | |
828 | vm_object_unlock(old_copy); /* done with old_copy */ | |
829 | } | |
830 | ||
831 | new_start = (vm_offset_t) 0; /* always shadow original at 0 */ | |
832 | new_end = (vm_offset_t) new_copy->size; /* for the whole object */ | |
833 | ||
834 | /* | |
835 | * Point the new copy at the existing object. | |
836 | */ | |
837 | ||
838 | new_copy->shadow = src_object; | |
839 | new_copy->shadow_offset = new_start; | |
840 | src_object->ref_count++; | |
841 | src_object->copy = new_copy; | |
842 | ||
843 | /* | |
844 | * Mark all the affected pages of the existing object | |
845 | * copy-on-write. | |
846 | */ | |
847 | p = (vm_page_t) queue_first(&src_object->memq); | |
848 | while (!queue_end(&src_object->memq, (queue_entry_t) p)) { | |
849 | if ((new_start <= p->offset) && (p->offset < new_end)) | |
850 | p->copy_on_write = TRUE; | |
851 | p = (vm_page_t) queue_next(&p->listq); | |
852 | } | |
853 | ||
854 | vm_object_unlock(src_object); | |
855 | ||
856 | *dst_object = new_copy; | |
857 | *dst_offset = src_offset - new_start; | |
858 | *src_needs_copy = FALSE; | |
859 | } | |
860 | ||
861 | /* | |
862 | * vm_object_shadow: | |
863 | * | |
864 | * Create a new object which is backed by the | |
865 | * specified existing object range. The source | |
866 | * object reference is deallocated. | |
867 | * | |
868 | * The new object and offset into that object | |
869 | * are returned in the source parameters. | |
870 | */ | |
871 | ||
872 | void vm_object_shadow(object, offset, length) | |
873 | vm_object_t *object; /* IN/OUT */ | |
874 | vm_offset_t *offset; /* IN/OUT */ | |
875 | vm_size_t length; | |
876 | { | |
877 | register vm_object_t source; | |
878 | register vm_object_t result; | |
879 | ||
880 | source = *object; | |
881 | ||
882 | /* | |
883 | * Allocate a new object with the given length | |
884 | */ | |
885 | ||
886 | if ((result = vm_object_allocate(length)) == NULL) | |
887 | panic("vm_object_shadow: no object for shadowing"); | |
888 | ||
889 | /* | |
890 | * The new object shadows the source object, adding | |
891 | * a reference to it. Our caller changes his reference | |
892 | * to point to the new object, removing a reference to | |
893 | * the source object. Net result: no change of reference | |
894 | * count. | |
895 | */ | |
896 | result->shadow = source; | |
897 | ||
898 | /* | |
899 | * Store the offset into the source object, | |
900 | * and fix up the offset into the new object. | |
901 | */ | |
902 | ||
903 | result->shadow_offset = *offset; | |
904 | ||
905 | /* | |
906 | * Return the new things | |
907 | */ | |
908 | ||
909 | *offset = 0; | |
910 | *object = result; | |
911 | } | |
912 | ||
913 | /* | |
914 | * Set the specified object's pager to the specified pager. | |
915 | */ | |
916 | ||
917 | void vm_object_setpager(object, pager, paging_offset, | |
918 | read_only) | |
919 | vm_object_t object; | |
920 | vm_pager_t pager; | |
921 | vm_offset_t paging_offset; | |
922 | boolean_t read_only; | |
923 | { | |
924 | #ifdef lint | |
925 | read_only++; /* No longer used */ | |
926 | #endif lint | |
927 | ||
928 | vm_object_lock(object); /* XXX ? */ | |
929 | object->pager = pager; | |
930 | object->paging_offset = paging_offset; | |
931 | vm_object_unlock(object); /* XXX ? */ | |
932 | } | |
933 | ||
934 | /* | |
935 | * vm_object_hash hashes the pager/id pair. | |
936 | */ | |
937 | ||
938 | #define vm_object_hash(pager) \ | |
939 | (((unsigned)pager)%VM_OBJECT_HASH_COUNT) | |
940 | ||
941 | /* | |
942 | * vm_object_lookup looks in the object cache for an object with the | |
943 | * specified pager and paging id. | |
944 | */ | |
945 | ||
946 | vm_object_t vm_object_lookup(pager) | |
947 | vm_pager_t pager; | |
948 | { | |
949 | register queue_t bucket; | |
950 | register vm_object_hash_entry_t entry; | |
951 | vm_object_t object; | |
952 | ||
953 | bucket = &vm_object_hashtable[vm_object_hash(pager)]; | |
954 | ||
955 | vm_object_cache_lock(); | |
956 | ||
957 | entry = (vm_object_hash_entry_t) queue_first(bucket); | |
958 | while (!queue_end(bucket, (queue_entry_t) entry)) { | |
959 | object = entry->object; | |
960 | if (object->pager == pager) { | |
961 | vm_object_lock(object); | |
962 | if (object->ref_count == 0) { | |
963 | queue_remove(&vm_object_cached_list, object, | |
964 | vm_object_t, cached_list); | |
965 | vm_object_cached--; | |
966 | } | |
967 | object->ref_count++; | |
968 | vm_object_unlock(object); | |
969 | vm_object_cache_unlock(); | |
970 | return(object); | |
971 | } | |
972 | entry = (vm_object_hash_entry_t) queue_next(&entry->hash_links); | |
973 | } | |
974 | ||
975 | vm_object_cache_unlock(); | |
976 | return(NULL); | |
977 | } | |
978 | ||
979 | /* | |
980 | * vm_object_enter enters the specified object/pager/id into | |
981 | * the hash table. | |
982 | */ | |
983 | ||
984 | void vm_object_enter(object, pager) | |
985 | vm_object_t object; | |
986 | vm_pager_t pager; | |
987 | { | |
988 | register queue_t bucket; | |
989 | register vm_object_hash_entry_t entry; | |
990 | ||
991 | /* | |
992 | * We don't cache null objects, and we can't cache | |
993 | * objects with the null pager. | |
994 | */ | |
995 | ||
996 | if (object == NULL) | |
997 | return; | |
998 | if (pager == NULL) | |
999 | return; | |
1000 | ||
1001 | bucket = &vm_object_hashtable[vm_object_hash(pager)]; | |
1002 | entry = (vm_object_hash_entry_t) | |
1003 | malloc((u_long)sizeof *entry, M_VMOBJHASH, M_WAITOK); | |
1004 | entry->object = object; | |
1005 | object->can_persist = TRUE; | |
1006 | ||
1007 | vm_object_cache_lock(); | |
1008 | queue_enter(bucket, entry, vm_object_hash_entry_t, hash_links); | |
1009 | vm_object_cache_unlock(); | |
1010 | } | |
1011 | ||
1012 | /* | |
1013 | * vm_object_remove: | |
1014 | * | |
1015 | * Remove the pager from the hash table. | |
1016 | * Note: This assumes that the object cache | |
1017 | * is locked. XXX this should be fixed | |
1018 | * by reorganizing vm_object_deallocate. | |
1019 | */ | |
4c45483e | 1020 | static void |
15637ed4 RG |
1021 | vm_object_remove(pager) |
1022 | register vm_pager_t pager; | |
1023 | { | |
1024 | register queue_t bucket; | |
1025 | register vm_object_hash_entry_t entry; | |
1026 | register vm_object_t object; | |
1027 | ||
1028 | bucket = &vm_object_hashtable[vm_object_hash(pager)]; | |
1029 | ||
1030 | entry = (vm_object_hash_entry_t) queue_first(bucket); | |
1031 | while (!queue_end(bucket, (queue_entry_t) entry)) { | |
1032 | object = entry->object; | |
1033 | if (object->pager == pager) { | |
1034 | queue_remove(bucket, entry, vm_object_hash_entry_t, | |
1035 | hash_links); | |
1036 | free((caddr_t)entry, M_VMOBJHASH); | |
1037 | break; | |
1038 | } | |
1039 | entry = (vm_object_hash_entry_t) queue_next(&entry->hash_links); | |
1040 | } | |
1041 | } | |
1042 | ||
1043 | /* | |
1044 | * vm_object_cache_clear removes all objects from the cache. | |
1045 | * | |
1046 | */ | |
1047 | ||
1048 | void vm_object_cache_clear() | |
1049 | { | |
1050 | register vm_object_t object; | |
1051 | ||
1052 | /* | |
1053 | * Remove each object in the cache by scanning down the | |
1054 | * list of cached objects. | |
1055 | */ | |
1056 | vm_object_cache_lock(); | |
1057 | while (!queue_empty(&vm_object_cached_list)) { | |
1058 | object = (vm_object_t) queue_first(&vm_object_cached_list); | |
1059 | vm_object_cache_unlock(); | |
1060 | ||
1061 | /* | |
1062 | * Note: it is important that we use vm_object_lookup | |
1063 | * to gain a reference, and not vm_object_reference, because | |
1064 | * the logic for removing an object from the cache lies in | |
1065 | * lookup. | |
1066 | */ | |
1067 | if (object != vm_object_lookup(object->pager)) | |
1068 | panic("vm_object_cache_clear: I'm sooo confused."); | |
1069 | pager_cache(object, FALSE); | |
1070 | ||
1071 | vm_object_cache_lock(); | |
1072 | } | |
1073 | vm_object_cache_unlock(); | |
1074 | } | |
1075 | ||
1076 | boolean_t vm_object_collapse_allowed = TRUE; | |
1077 | /* | |
1078 | * vm_object_collapse: | |
1079 | * | |
1080 | * Collapse an object with the object backing it. | |
1081 | * Pages in the backing object are moved into the | |
1082 | * parent, and the backing object is deallocated. | |
1083 | * | |
1084 | * Requires that the object be locked and the page | |
1085 | * queues be unlocked. | |
1086 | * | |
1087 | */ | |
1088 | void vm_object_collapse(object) | |
1089 | register vm_object_t object; | |
1090 | ||
1091 | { | |
1092 | register vm_object_t backing_object; | |
1093 | register vm_offset_t backing_offset; | |
1094 | register vm_size_t size; | |
1095 | register vm_offset_t new_offset; | |
1096 | register vm_page_t p, pp; | |
1097 | ||
1098 | if (!vm_object_collapse_allowed) | |
1099 | return; | |
1100 | ||
1101 | while (TRUE) { | |
1102 | /* | |
1103 | * Verify that the conditions are right for collapse: | |
1104 | * | |
1105 | * The object exists and no pages in it are currently | |
1106 | * being paged out (or have ever been paged out). | |
1107 | */ | |
1108 | if (object == NULL || | |
1109 | object->paging_in_progress != 0 || | |
1110 | object->pager != NULL) | |
1111 | return; | |
1112 | ||
1113 | /* | |
1114 | * There is a backing object, and | |
1115 | */ | |
1116 | ||
1117 | if ((backing_object = object->shadow) == NULL) | |
1118 | return; | |
1119 | ||
1120 | vm_object_lock(backing_object); | |
1121 | /* | |
1122 | * ... | |
1123 | * The backing object is not read_only, | |
1124 | * and no pages in the backing object are | |
1125 | * currently being paged out. | |
1126 | * The backing object is internal. | |
1127 | */ | |
1128 | ||
1129 | if (!backing_object->internal || | |
1130 | backing_object->paging_in_progress != 0) { | |
1131 | vm_object_unlock(backing_object); | |
1132 | return; | |
1133 | } | |
1134 | ||
1135 | /* | |
1136 | * The backing object can't be a copy-object: | |
1137 | * the shadow_offset for the copy-object must stay | |
1138 | * as 0. Furthermore (for the 'we have all the | |
1139 | * pages' case), if we bypass backing_object and | |
1140 | * just shadow the next object in the chain, old | |
1141 | * pages from that object would then have to be copied | |
1142 | * BOTH into the (former) backing_object and into the | |
1143 | * parent object. | |
1144 | */ | |
1145 | if (backing_object->shadow != NULL && | |
1146 | backing_object->shadow->copy != NULL) { | |
1147 | vm_object_unlock(backing_object); | |
1148 | return; | |
1149 | } | |
1150 | ||
1151 | /* | |
1152 | * We know that we can either collapse the backing | |
1153 | * object (if the parent is the only reference to | |
1154 | * it) or (perhaps) remove the parent's reference | |
1155 | * to it. | |
1156 | */ | |
1157 | ||
1158 | backing_offset = object->shadow_offset; | |
1159 | size = object->size; | |
1160 | ||
1161 | /* | |
1162 | * If there is exactly one reference to the backing | |
1163 | * object, we can collapse it into the parent. | |
1164 | */ | |
1165 | ||
1166 | if (backing_object->ref_count == 1) { | |
1167 | ||
1168 | /* | |
1169 | * We can collapse the backing object. | |
1170 | * | |
1171 | * Move all in-memory pages from backing_object | |
1172 | * to the parent. Pages that have been paged out | |
1173 | * will be overwritten by any of the parent's | |
1174 | * pages that shadow them. | |
1175 | */ | |
1176 | ||
1177 | while (!queue_empty(&backing_object->memq)) { | |
1178 | ||
1179 | p = (vm_page_t) | |
1180 | queue_first(&backing_object->memq); | |
1181 | ||
1182 | new_offset = (p->offset - backing_offset); | |
1183 | ||
1184 | /* | |
1185 | * If the parent has a page here, or if | |
1186 | * this page falls outside the parent, | |
1187 | * dispose of it. | |
1188 | * | |
1189 | * Otherwise, move it as planned. | |
1190 | */ | |
1191 | ||
1192 | if (p->offset < backing_offset || | |
1193 | new_offset >= size) { | |
1194 | vm_page_lock_queues(); | |
1195 | vm_page_free(p); | |
1196 | vm_page_unlock_queues(); | |
1197 | } else { | |
1198 | pp = vm_page_lookup(object, new_offset); | |
1199 | if (pp != NULL && !pp->fake) { | |
1200 | vm_page_lock_queues(); | |
1201 | vm_page_free(p); | |
1202 | vm_page_unlock_queues(); | |
1203 | } | |
1204 | else { | |
1205 | if (pp) { | |
8820571b NW |
1206 | #if 1 |
1207 | /* | |
1208 | * This should never happen -- the | |
1209 | * parent cannot have ever had an | |
1210 | * external memory object, and thus | |
1211 | * cannot have absent pages. | |
1212 | */ | |
1213 | panic("vm_object_collapse: bad case"); | |
1214 | /* andrew@werple.apana.org.au - from | |
1215 | mach 3.0 VM */ | |
1216 | #else | |
15637ed4 RG |
1217 | /* may be someone waiting for it */ |
1218 | PAGE_WAKEUP(pp); | |
1219 | vm_page_lock_queues(); | |
1220 | vm_page_free(pp); | |
1221 | vm_page_unlock_queues(); | |
8820571b | 1222 | #endif |
15637ed4 | 1223 | } |
8820571b NW |
1224 | /* |
1225 | * Parent now has no page. | |
1226 | * Move the backing object's page | |
1227 | * up. | |
1228 | */ | |
15637ed4 RG |
1229 | vm_page_rename(p, object, new_offset); |
1230 | } | |
1231 | } | |
1232 | } | |
1233 | ||
1234 | /* | |
1235 | * Move the pager from backing_object to object. | |
1236 | * | |
1237 | * XXX We're only using part of the paging space | |
1238 | * for keeps now... we ought to discard the | |
1239 | * unused portion. | |
1240 | */ | |
1241 | ||
e475daaa JH |
1242 | /* |
1243 | * Remove backing_object from the object hashtable now. | |
1244 | * This is necessary since its pager is going away | |
1245 | * and therefore it is not going to be removed from | |
1246 | * hashtable in vm_object_deallocate(). | |
1247 | * | |
1248 | * NOTE - backing_object can only get at this stage if | |
1249 | * it has an internal pager. It is not normally on the | |
1250 | * hashtable unless it was put there by eg. vm_mmap() | |
1251 | * | |
1252 | * XXX - Need I worry here about *named* ANON pagers ? | |
1253 | */ | |
1254 | ||
1255 | if (backing_object->pager) { | |
1256 | vm_object_remove(backing_object->pager); | |
1257 | } | |
15637ed4 | 1258 | object->pager = backing_object->pager; |
8820571b NW |
1259 | #if 1 |
1260 | /* Mach 3.0 code */ | |
1261 | /* andrew@werple.apana.org.au, 12 Feb 1993 */ | |
1262 | ||
1263 | /* | |
1264 | * If there is no pager, leave paging-offset alone. | |
1265 | */ | |
1266 | if (object->pager) | |
1267 | object->paging_offset = | |
1268 | backing_object->paging_offset + | |
1269 | backing_offset; | |
1270 | #else | |
1271 | /* old VM 2.5 version */ | |
15637ed4 | 1272 | object->paging_offset += backing_offset; |
8820571b | 1273 | #endif |
15637ed4 RG |
1274 | |
1275 | backing_object->pager = NULL; | |
1276 | ||
1277 | /* | |
1278 | * Object now shadows whatever backing_object did. | |
1279 | * Note that the reference to backing_object->shadow | |
1280 | * moves from within backing_object to within object. | |
1281 | */ | |
1282 | ||
1283 | object->shadow = backing_object->shadow; | |
1284 | object->shadow_offset += backing_object->shadow_offset; | |
1285 | if (object->shadow != NULL && | |
1286 | object->shadow->copy != NULL) { | |
1287 | panic("vm_object_collapse: we collapsed a copy-object!"); | |
1288 | } | |
1289 | /* | |
1290 | * Discard backing_object. | |
1291 | * | |
1292 | * Since the backing object has no pages, no | |
1293 | * pager left, and no object references within it, | |
1294 | * all that is necessary is to dispose of it. | |
1295 | */ | |
1296 | ||
1297 | vm_object_unlock(backing_object); | |
1298 | ||
1299 | simple_lock(&vm_object_list_lock); | |
1300 | queue_remove(&vm_object_list, backing_object, | |
1301 | vm_object_t, object_list); | |
1302 | vm_object_count--; | |
1303 | simple_unlock(&vm_object_list_lock); | |
1304 | ||
1305 | free((caddr_t)backing_object, M_VMOBJ); | |
1306 | ||
1307 | object_collapses++; | |
1308 | } | |
1309 | else { | |
1310 | /* | |
1311 | * If all of the pages in the backing object are | |
1312 | * shadowed by the parent object, the parent | |
1313 | * object no longer has to shadow the backing | |
1314 | * object; it can shadow the next one in the | |
1315 | * chain. | |
1316 | * | |
1317 | * The backing object must not be paged out - we'd | |
1318 | * have to check all of the paged-out pages, as | |
1319 | * well. | |
1320 | */ | |
1321 | ||
1322 | if (backing_object->pager != NULL) { | |
1323 | vm_object_unlock(backing_object); | |
1324 | return; | |
1325 | } | |
1326 | ||
1327 | /* | |
1328 | * Should have a check for a 'small' number | |
1329 | * of pages here. | |
1330 | */ | |
1331 | ||
1332 | p = (vm_page_t) queue_first(&backing_object->memq); | |
1333 | while (!queue_end(&backing_object->memq, | |
1334 | (queue_entry_t) p)) { | |
1335 | ||
1336 | new_offset = (p->offset - backing_offset); | |
1337 | ||
1338 | /* | |
1339 | * If the parent has a page here, or if | |
1340 | * this page falls outside the parent, | |
1341 | * keep going. | |
1342 | * | |
1343 | * Otherwise, the backing_object must be | |
1344 | * left in the chain. | |
1345 | */ | |
1346 | ||
1347 | if (p->offset >= backing_offset && | |
1348 | new_offset <= size && | |
1349 | ((pp = vm_page_lookup(object, new_offset)) | |
1350 | == NULL || | |
1351 | pp->fake)) { | |
1352 | /* | |
1353 | * Page still needed. | |
1354 | * Can't go any further. | |
1355 | */ | |
1356 | vm_object_unlock(backing_object); | |
1357 | return; | |
1358 | } | |
1359 | p = (vm_page_t) queue_next(&p->listq); | |
1360 | } | |
1361 | ||
1362 | /* | |
1363 | * Make the parent shadow the next object | |
1364 | * in the chain. Deallocating backing_object | |
1365 | * will not remove it, since its reference | |
1366 | * count is at least 2. | |
1367 | */ | |
1368 | ||
1369 | vm_object_reference(object->shadow = backing_object->shadow); | |
1370 | object->shadow_offset += backing_object->shadow_offset; | |
1371 | ||
8820571b NW |
1372 | #if 1 |
1373 | /* Mach 3.0 code */ | |
1374 | /* andrew@werple.apana.org.au, 12 Feb 1993 */ | |
1375 | ||
1376 | /* | |
1377 | * Backing object might have had a copy pointer | |
1378 | * to us. If it did, clear it. | |
1379 | */ | |
1380 | if (backing_object->copy == object) | |
1381 | backing_object->copy = NULL; | |
1382 | #endif | |
1383 | ||
15637ed4 RG |
1384 | /* Drop the reference count on backing_object. |
1385 | * Since its ref_count was at least 2, it | |
1386 | * will not vanish; so we don't need to call | |
1387 | * vm_object_deallocate. | |
1388 | */ | |
1389 | backing_object->ref_count--; | |
1390 | vm_object_unlock(backing_object); | |
1391 | ||
1392 | object_bypasses ++; | |
1393 | ||
1394 | } | |
1395 | ||
1396 | /* | |
1397 | * Try again with this object's new backing object. | |
1398 | */ | |
1399 | } | |
1400 | } | |
1401 | ||
1402 | /* | |
1403 | * vm_object_page_remove: [internal] | |
1404 | * | |
1405 | * Removes all physical pages in the specified | |
1406 | * object range from the object's list of pages. | |
1407 | * | |
1408 | * The object must be locked. | |
1409 | */ | |
1410 | void vm_object_page_remove(object, start, end) | |
1411 | register vm_object_t object; | |
1412 | register vm_offset_t start; | |
1413 | register vm_offset_t end; | |
1414 | { | |
1415 | register vm_page_t p, next; | |
1416 | ||
1417 | if (object == NULL) | |
1418 | return; | |
1419 | ||
1420 | p = (vm_page_t) queue_first(&object->memq); | |
1421 | while (!queue_end(&object->memq, (queue_entry_t) p)) { | |
1422 | next = (vm_page_t) queue_next(&p->listq); | |
1423 | if ((start <= p->offset) && (p->offset < end)) { | |
1424 | pmap_page_protect(VM_PAGE_TO_PHYS(p), VM_PROT_NONE); | |
1425 | vm_page_lock_queues(); | |
1426 | vm_page_free(p); | |
1427 | vm_page_unlock_queues(); | |
1428 | } | |
1429 | p = next; | |
1430 | } | |
1431 | } | |
1432 | ||
1433 | /* | |
1434 | * Routine: vm_object_coalesce | |
1435 | * Function: Coalesces two objects backing up adjoining | |
1436 | * regions of memory into a single object. | |
1437 | * | |
1438 | * returns TRUE if objects were combined. | |
1439 | * | |
1440 | * NOTE: Only works at the moment if the second object is NULL - | |
1441 | * if it's not, which object do we lock first? | |
1442 | * | |
1443 | * Parameters: | |
1444 | * prev_object First object to coalesce | |
1445 | * prev_offset Offset into prev_object | |
1446 | * next_object Second object into coalesce | |
1447 | * next_offset Offset into next_object | |
1448 | * | |
1449 | * prev_size Size of reference to prev_object | |
1450 | * next_size Size of reference to next_object | |
1451 | * | |
1452 | * Conditions: | |
1453 | * The object must *not* be locked. | |
1454 | */ | |
1455 | boolean_t vm_object_coalesce(prev_object, next_object, | |
1456 | prev_offset, next_offset, | |
1457 | prev_size, next_size) | |
1458 | ||
1459 | register vm_object_t prev_object; | |
1460 | vm_object_t next_object; | |
1461 | vm_offset_t prev_offset, next_offset; | |
1462 | vm_size_t prev_size, next_size; | |
1463 | { | |
1464 | vm_size_t newsize; | |
1465 | ||
1466 | #ifdef lint | |
1467 | next_offset++; | |
1468 | #endif lint | |
1469 | ||
1470 | if (next_object != NULL) { | |
1471 | return(FALSE); | |
1472 | } | |
1473 | ||
1474 | if (prev_object == NULL) { | |
1475 | return(TRUE); | |
1476 | } | |
1477 | ||
1478 | vm_object_lock(prev_object); | |
1479 | ||
1480 | /* | |
1481 | * Try to collapse the object first | |
1482 | */ | |
1483 | vm_object_collapse(prev_object); | |
1484 | ||
1485 | /* | |
1486 | * Can't coalesce if: | |
1487 | * . more than one reference | |
1488 | * . paged out | |
1489 | * . shadows another object | |
1490 | * . has a copy elsewhere | |
1491 | * (any of which mean that the pages not mapped to | |
1492 | * prev_entry may be in use anyway) | |
1493 | */ | |
1494 | ||
1495 | if (prev_object->ref_count > 1 || | |
1496 | prev_object->pager != NULL || | |
1497 | prev_object->shadow != NULL || | |
1498 | prev_object->copy != NULL) { | |
1499 | vm_object_unlock(prev_object); | |
1500 | return(FALSE); | |
1501 | } | |
1502 | ||
1503 | /* | |
1504 | * Remove any pages that may still be in the object from | |
1505 | * a previous deallocation. | |
1506 | */ | |
1507 | ||
1508 | vm_object_page_remove(prev_object, | |
1509 | prev_offset + prev_size, | |
1510 | prev_offset + prev_size + next_size); | |
1511 | ||
1512 | /* | |
1513 | * Extend the object if necessary. | |
1514 | */ | |
1515 | newsize = prev_offset + prev_size + next_size; | |
1516 | if (newsize > prev_object->size) | |
1517 | prev_object->size = newsize; | |
1518 | ||
1519 | vm_object_unlock(prev_object); | |
1520 | return(TRUE); | |
1521 | } | |
1522 | ||
d55b6cf4 | 1523 | #if defined(DEBUG) || (NDDB > 0) |
15637ed4 RG |
1524 | /* |
1525 | * vm_object_print: [ debug ] | |
1526 | */ | |
1527 | void vm_object_print(object, full) | |
1528 | vm_object_t object; | |
1529 | boolean_t full; | |
1530 | { | |
1531 | register vm_page_t p; | |
1532 | extern indent; | |
1533 | ||
1534 | register int count; | |
1535 | ||
1536 | if (object == NULL) | |
1537 | return; | |
1538 | ||
1539 | iprintf("Object 0x%x: size=0x%x, res=%d, ref=%d, ", | |
1540 | (int) object, (int) object->size, | |
1541 | object->resident_page_count, object->ref_count); | |
1542 | printf("pager=0x%x+0x%x, shadow=(0x%x)+0x%x\n", | |
1543 | (int) object->pager, (int) object->paging_offset, | |
1544 | (int) object->shadow, (int) object->shadow_offset); | |
1545 | printf("cache: next=0x%x, prev=0x%x\n", | |
1546 | object->cached_list.next, object->cached_list.prev); | |
1547 | ||
1548 | if (!full) | |
1549 | return; | |
1550 | ||
1551 | indent += 2; | |
1552 | count = 0; | |
1553 | p = (vm_page_t) queue_first(&object->memq); | |
1554 | while (!queue_end(&object->memq, (queue_entry_t) p)) { | |
1555 | if (count == 0) | |
1556 | iprintf("memory:="); | |
1557 | else if (count == 6) { | |
1558 | printf("\n"); | |
1559 | iprintf(" ..."); | |
1560 | count = 0; | |
1561 | } else | |
1562 | printf(","); | |
1563 | count++; | |
1564 | ||
1565 | printf("(off=0x%x,page=0x%x)", p->offset, VM_PAGE_TO_PHYS(p)); | |
1566 | p = (vm_page_t) queue_next(&p->listq); | |
1567 | } | |
1568 | if (count != 0) | |
1569 | printf("\n"); | |
1570 | indent -= 2; | |
1571 | } | |
d55b6cf4 | 1572 | #endif /* defined(DEBUG) || (NDDB > 0) */ |