Commit | Line | Data |
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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 |
41aefbec | 37 | * $Id: vm_object.c,v 1.22 1994/03/05 03:22:46 davidg Exp $ |
55768178 DG |
38 | * |
39 | * | |
15637ed4 RG |
40 | * Copyright (c) 1987, 1990 Carnegie-Mellon University. |
41 | * All rights reserved. | |
42 | * | |
43 | * Authors: Avadis Tevanian, Jr., Michael Wayne Young | |
44 | * | |
45 | * Permission to use, copy, modify and distribute this software and | |
46 | * its documentation is hereby granted, provided that both the copyright | |
47 | * notice and this permission notice appear in all copies of the | |
48 | * software, derivative works or modified versions, and any portions | |
49 | * thereof, and that both notices appear in supporting documentation. | |
50 | * | |
51 | * CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS" | |
52 | * CONDITION. CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND | |
53 | * FOR ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE. | |
54 | * | |
55 | * Carnegie Mellon requests users of this software to return to | |
56 | * | |
57 | * Software Distribution Coordinator or Software.Distribution@CS.CMU.EDU | |
58 | * School of Computer Science | |
59 | * Carnegie Mellon University | |
60 | * Pittsburgh PA 15213-3890 | |
61 | * | |
62 | * any improvements or extensions that they make and grant Carnegie the | |
63 | * rights to redistribute these changes. | |
15637ed4 RG |
64 | */ |
65 | ||
66 | /* | |
67 | * Virtual memory object module. | |
68 | */ | |
69 | ||
55768178 | 70 | #include "ddb.h" |
15637ed4 RG |
71 | #include "param.h" |
72 | #include "malloc.h" | |
55768178 | 73 | #include "systm.h" |
15637ed4 RG |
74 | |
75 | #include "vm.h" | |
76 | #include "vm_page.h" | |
55768178 DG |
77 | #include "proc.h" |
78 | ||
fde1aeb2 | 79 | |
4c45483e | 80 | static void _vm_object_allocate(vm_size_t, vm_object_t); |
55768178 | 81 | void vm_object_deactivate_pages(vm_object_t); |
4c45483e GW |
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 | ||
55768178 | 111 | |
bbc3f849 GW |
112 | queue_head_t vm_object_cached_list; /* list of objects persisting */ |
113 | int vm_object_cached; /* size of cached list */ | |
114 | simple_lock_data_t vm_cache_lock; /* lock for object cache */ | |
115 | ||
116 | queue_head_t vm_object_list; /* list of allocated objects */ | |
117 | long vm_object_count; /* count of all objects */ | |
118 | simple_lock_data_t vm_object_list_lock; | |
119 | /* lock for object list and count */ | |
120 | ||
121 | vm_object_t kernel_object; /* the single kernel object */ | |
55768178 | 122 | vm_object_t kmem_object; /* the kernel malloc object */ |
15637ed4 RG |
123 | struct vm_object kernel_object_store; |
124 | struct vm_object kmem_object_store; | |
125 | ||
ff1a3ad7 | 126 | extern int vm_cache_max; |
55768178 | 127 | #define VM_OBJECT_HASH_COUNT 127 |
55768178 | 128 | |
15637ed4 RG |
129 | queue_head_t vm_object_hashtable[VM_OBJECT_HASH_COUNT]; |
130 | ||
131 | long object_collapses = 0; | |
132 | long object_bypasses = 0; | |
133 | ||
55768178 DG |
134 | /* |
135 | * internal version of vm_object_allocate | |
136 | */ | |
137 | static inline void | |
138 | _vm_object_allocate(size, object) | |
139 | vm_size_t size; | |
140 | register vm_object_t object; | |
141 | { | |
142 | queue_init(&object->memq); | |
143 | vm_object_lock_init(object); | |
144 | object->ref_count = 1; | |
145 | object->resident_page_count = 0; | |
146 | object->size = size; | |
147 | object->can_persist = FALSE; | |
148 | object->paging_in_progress = 0; | |
149 | object->copy = NULL; | |
150 | ||
151 | /* | |
152 | * Object starts out read-write, with no pager. | |
153 | */ | |
154 | ||
155 | object->pager = NULL; | |
156 | object->internal = TRUE; /* vm_allocate_with_pager will reset */ | |
157 | object->paging_offset = 0; | |
158 | object->shadow = NULL; | |
159 | object->shadow_offset = (vm_offset_t) 0; | |
160 | ||
161 | simple_lock(&vm_object_list_lock); | |
162 | queue_enter(&vm_object_list, object, vm_object_t, object_list); | |
163 | vm_object_count++; | |
164 | simple_unlock(&vm_object_list_lock); | |
165 | } | |
166 | ||
15637ed4 RG |
167 | /* |
168 | * vm_object_init: | |
169 | * | |
170 | * Initialize the VM objects module. | |
171 | */ | |
55768178 DG |
172 | void |
173 | vm_object_init() | |
15637ed4 RG |
174 | { |
175 | register int i; | |
176 | ||
177 | queue_init(&vm_object_cached_list); | |
178 | queue_init(&vm_object_list); | |
179 | vm_object_count = 0; | |
180 | simple_lock_init(&vm_cache_lock); | |
181 | simple_lock_init(&vm_object_list_lock); | |
182 | ||
183 | for (i = 0; i < VM_OBJECT_HASH_COUNT; i++) | |
184 | queue_init(&vm_object_hashtable[i]); | |
185 | ||
186 | kernel_object = &kernel_object_store; | |
187 | _vm_object_allocate(VM_MAX_KERNEL_ADDRESS - VM_MIN_KERNEL_ADDRESS, | |
188 | kernel_object); | |
189 | ||
190 | kmem_object = &kmem_object_store; | |
55768178 DG |
191 | _vm_object_allocate(VM_MAX_KERNEL_ADDRESS - VM_MIN_KERNEL_ADDRESS, |
192 | kmem_object); | |
15637ed4 RG |
193 | } |
194 | ||
195 | /* | |
196 | * vm_object_allocate: | |
197 | * | |
198 | * Returns a new object with the given size. | |
199 | */ | |
200 | ||
55768178 DG |
201 | vm_object_t |
202 | vm_object_allocate(size) | |
15637ed4 RG |
203 | vm_size_t size; |
204 | { | |
205 | register vm_object_t result; | |
55768178 DG |
206 | int s; |
207 | ||
a200ca2b DG |
208 | result = (vm_object_t) |
209 | malloc((u_long)sizeof *result, M_VMOBJ, M_WAITOK); | |
55768178 | 210 | |
15637ed4 RG |
211 | |
212 | _vm_object_allocate(size, result); | |
213 | ||
214 | return(result); | |
215 | } | |
216 | ||
15637ed4 RG |
217 | |
218 | /* | |
219 | * vm_object_reference: | |
220 | * | |
221 | * Gets another reference to the given object. | |
222 | */ | |
55768178 DG |
223 | inline void |
224 | vm_object_reference(object) | |
15637ed4 RG |
225 | register vm_object_t object; |
226 | { | |
227 | if (object == NULL) | |
228 | return; | |
229 | ||
230 | vm_object_lock(object); | |
231 | object->ref_count++; | |
232 | vm_object_unlock(object); | |
233 | } | |
234 | ||
235 | /* | |
236 | * vm_object_deallocate: | |
237 | * | |
238 | * Release a reference to the specified object, | |
239 | * gained either through a vm_object_allocate | |
240 | * or a vm_object_reference call. When all references | |
241 | * are gone, storage associated with this object | |
242 | * may be relinquished. | |
243 | * | |
244 | * No object may be locked. | |
245 | */ | |
55768178 DG |
246 | void |
247 | vm_object_deallocate(object) | |
248 | vm_object_t object; | |
15637ed4 RG |
249 | { |
250 | vm_object_t temp; | |
251 | ||
252 | while (object != NULL) { | |
253 | ||
254 | /* | |
255 | * The cache holds a reference (uncounted) to | |
256 | * the object; we must lock it before removing | |
257 | * the object. | |
258 | */ | |
259 | ||
260 | vm_object_cache_lock(); | |
261 | ||
262 | /* | |
263 | * Lose the reference | |
264 | */ | |
265 | vm_object_lock(object); | |
266 | if (--(object->ref_count) != 0) { | |
267 | ||
55768178 | 268 | vm_object_unlock(object); |
15637ed4 RG |
269 | /* |
270 | * If there are still references, then | |
271 | * we are done. | |
272 | */ | |
15637ed4 RG |
273 | vm_object_cache_unlock(); |
274 | return; | |
275 | } | |
276 | ||
277 | /* | |
278 | * See if this object can persist. If so, enter | |
279 | * it in the cache, then deactivate all of its | |
280 | * pages. | |
281 | */ | |
282 | ||
283 | if (object->can_persist) { | |
15637ed4 RG |
284 | |
285 | queue_enter(&vm_object_cached_list, object, | |
286 | vm_object_t, cached_list); | |
287 | vm_object_cached++; | |
288 | vm_object_cache_unlock(); | |
289 | ||
55768178 | 290 | /* vm_object_deactivate_pages(object); */ |
15637ed4 RG |
291 | vm_object_unlock(object); |
292 | ||
293 | vm_object_cache_trim(); | |
294 | return; | |
295 | } | |
15637ed4 RG |
296 | |
297 | /* | |
298 | * Make sure no one can look us up now. | |
299 | */ | |
300 | vm_object_remove(object->pager); | |
301 | vm_object_cache_unlock(); | |
55768178 | 302 | |
15637ed4 RG |
303 | temp = object->shadow; |
304 | vm_object_terminate(object); | |
305 | /* unlocks and deallocates object */ | |
306 | object = temp; | |
307 | } | |
308 | } | |
309 | ||
15637ed4 RG |
310 | /* |
311 | * vm_object_terminate actually destroys the specified object, freeing | |
312 | * up all previously used resources. | |
313 | * | |
314 | * The object must be locked. | |
315 | */ | |
55768178 DG |
316 | void |
317 | vm_object_terminate(object) | |
15637ed4 RG |
318 | register vm_object_t object; |
319 | { | |
320 | register vm_page_t p; | |
321 | vm_object_t shadow_object; | |
55768178 | 322 | int s; |
15637ed4 RG |
323 | |
324 | /* | |
325 | * Detach the object from its shadow if we are the shadow's | |
326 | * copy. | |
327 | */ | |
328 | if ((shadow_object = object->shadow) != NULL) { | |
329 | vm_object_lock(shadow_object); | |
330 | if (shadow_object->copy == object) | |
331 | shadow_object->copy = NULL; | |
55768178 | 332 | /* |
15637ed4 RG |
333 | else if (shadow_object->copy != NULL) |
334 | panic("vm_object_terminate: copy/shadow inconsistency"); | |
55768178 | 335 | */ |
15637ed4 RG |
336 | vm_object_unlock(shadow_object); |
337 | } | |
338 | ||
a200ca2b DG |
339 | /* |
340 | * optim: get rid of any pages that we can right now | |
341 | * so the pageout daemon can't get any more to page | |
342 | * out at rundown. | |
343 | */ | |
691d9ea2 | 344 | #if 0 |
a200ca2b DG |
345 | p = (vm_page_t) queue_first(&object->memq); |
346 | while (!queue_end(&object->memq, (queue_entry_t) p)) { | |
347 | vm_page_t next = (vm_page_t) queue_next(&p->listq); | |
348 | VM_PAGE_CHECK(p); | |
349 | vm_page_lock_queues(); | |
350 | ||
351 | if (p->flags & PG_BUSY) { | |
352 | p = next; | |
353 | vm_page_unlock_queues(); | |
354 | continue; | |
355 | } | |
356 | if (!object->internal) { | |
357 | if ((p->flags & PG_CLEAN) == 0) { | |
358 | p = next; | |
359 | vm_page_unlock_queues(); | |
360 | continue; | |
361 | } | |
362 | ||
363 | if (pmap_is_modified(VM_PAGE_TO_PHYS(p))) { | |
364 | p->flags &= ~PG_CLEAN; | |
365 | p = next; | |
366 | vm_page_unlock_queues(); | |
367 | continue; | |
368 | } | |
369 | } | |
370 | ||
371 | vm_page_free(p); | |
372 | vm_page_unlock_queues(); | |
373 | p = next; | |
374 | } | |
691d9ea2 | 375 | #endif |
a200ca2b | 376 | |
15637ed4 RG |
377 | /* |
378 | * Wait until the pageout daemon is through | |
379 | * with the object. | |
380 | */ | |
381 | ||
382 | while (object->paging_in_progress != 0) { | |
55768178 | 383 | vm_object_sleep(object, object, FALSE); |
15637ed4 RG |
384 | vm_object_lock(object); |
385 | } | |
15637ed4 RG |
386 | |
387 | /* | |
388 | * While the paging system is locked, | |
389 | * pull the object's pages off the active | |
390 | * and inactive queues. This keeps the | |
391 | * pageout daemon from playing with them | |
392 | * during vm_pager_deallocate. | |
393 | * | |
394 | * We can't free the pages yet, because the | |
395 | * object's pager may have to write them out | |
396 | * before deallocating the paging space. | |
397 | */ | |
398 | ||
399 | p = (vm_page_t) queue_first(&object->memq); | |
400 | while (!queue_end(&object->memq, (queue_entry_t) p)) { | |
401 | VM_PAGE_CHECK(p); | |
402 | ||
403 | vm_page_lock_queues(); | |
55768178 | 404 | s = vm_disable_intr(); |
fd76afd7 | 405 | if (p->flags & PG_ACTIVE) { |
15637ed4 RG |
406 | queue_remove(&vm_page_queue_active, p, vm_page_t, |
407 | pageq); | |
fd76afd7 | 408 | p->flags &= ~PG_ACTIVE; |
15637ed4 RG |
409 | vm_page_active_count--; |
410 | } | |
411 | ||
fd76afd7 | 412 | if (p->flags & PG_INACTIVE) { |
15637ed4 RG |
413 | queue_remove(&vm_page_queue_inactive, p, vm_page_t, |
414 | pageq); | |
fd76afd7 | 415 | p->flags &= ~PG_INACTIVE; |
15637ed4 RG |
416 | vm_page_inactive_count--; |
417 | } | |
55768178 | 418 | vm_set_intr(s); |
15637ed4 RG |
419 | vm_page_unlock_queues(); |
420 | p = (vm_page_t) queue_next(&p->listq); | |
421 | } | |
422 | ||
423 | vm_object_unlock(object); | |
424 | ||
425 | if (object->paging_in_progress != 0) | |
426 | panic("vm_object_deallocate: pageout in progress"); | |
427 | ||
428 | /* | |
429 | * Clean and free the pages, as appropriate. | |
430 | * All references to the object are gone, | |
431 | * so we don't need to lock it. | |
432 | */ | |
433 | ||
434 | if (!object->internal) { | |
435 | vm_object_lock(object); | |
436 | vm_object_page_clean(object, 0, 0); | |
437 | vm_object_unlock(object); | |
438 | } | |
55768178 | 439 | |
15637ed4 RG |
440 | while (!queue_empty(&object->memq)) { |
441 | p = (vm_page_t) queue_first(&object->memq); | |
442 | ||
443 | VM_PAGE_CHECK(p); | |
444 | ||
445 | vm_page_lock_queues(); | |
446 | vm_page_free(p); | |
447 | vm_page_unlock_queues(); | |
448 | } | |
449 | ||
450 | /* | |
451 | * Let the pager know object is dead. | |
452 | */ | |
453 | ||
55768178 | 454 | if (object->pager != NULL) { |
15637ed4 | 455 | vm_pager_deallocate(object->pager); |
55768178 | 456 | } |
15637ed4 RG |
457 | |
458 | ||
459 | simple_lock(&vm_object_list_lock); | |
460 | queue_remove(&vm_object_list, object, vm_object_t, object_list); | |
461 | vm_object_count--; | |
462 | simple_unlock(&vm_object_list_lock); | |
463 | ||
464 | /* | |
465 | * Free the space for the object. | |
466 | */ | |
467 | ||
a200ca2b | 468 | free((caddr_t)object, M_VMOBJ); |
15637ed4 RG |
469 | } |
470 | ||
471 | /* | |
472 | * vm_object_page_clean | |
473 | * | |
474 | * Clean all dirty pages in the specified range of object. | |
475 | * Leaves page on whatever queue it is currently on. | |
476 | * | |
477 | * Odd semantics: if start == end, we clean everything. | |
478 | * | |
479 | * The object must be locked. | |
480 | */ | |
4c45483e | 481 | void |
15637ed4 RG |
482 | vm_object_page_clean(object, start, end) |
483 | register vm_object_t object; | |
484 | register vm_offset_t start; | |
485 | register vm_offset_t end; | |
486 | { | |
487 | register vm_page_t p; | |
55768178 DG |
488 | int s; |
489 | int size; | |
15637ed4 RG |
490 | |
491 | if (object->pager == NULL) | |
492 | return; | |
493 | ||
55768178 DG |
494 | if (start != end) { |
495 | start = trunc_page(start); | |
496 | end = round_page(end); | |
497 | } | |
498 | size = end - start; | |
499 | ||
15637ed4 RG |
500 | again: |
501 | p = (vm_page_t) queue_first(&object->memq); | |
55768178 DG |
502 | while (!queue_end(&object->memq, (queue_entry_t) p) && ((start == end) || (size != 0) ) ) { |
503 | if (start == end || (p->offset >= start && p->offset < end)) { | |
ce619eaa | 504 | if (p->flags & PG_BUSY) |
55768178 DG |
505 | goto next; |
506 | ||
507 | size -= PAGE_SIZE; | |
508 | ||
509 | if ((p->flags & PG_CLEAN) | |
510 | && pmap_is_modified(VM_PAGE_TO_PHYS(p))) | |
fd76afd7 | 511 | p->flags &= ~PG_CLEAN; |
55768178 DG |
512 | |
513 | if (p->flags & PG_ACTIVE) | |
514 | vm_page_deactivate(p); | |
a200ca2b | 515 | |
55768178 | 516 | if ((p->flags & PG_CLEAN) == 0) { |
fd76afd7 | 517 | p->flags |= PG_BUSY; |
15637ed4 RG |
518 | object->paging_in_progress++; |
519 | vm_object_unlock(object); | |
520 | (void) vm_pager_put(object->pager, p, TRUE); | |
521 | vm_object_lock(object); | |
522 | object->paging_in_progress--; | |
55768178 DG |
523 | if (object->paging_in_progress == 0) |
524 | wakeup((caddr_t) object); | |
15637ed4 RG |
525 | PAGE_WAKEUP(p); |
526 | goto again; | |
527 | } | |
528 | } | |
55768178 | 529 | next: |
15637ed4 RG |
530 | p = (vm_page_t) queue_next(&p->listq); |
531 | } | |
55768178 | 532 | wakeup((caddr_t)object); |
15637ed4 RG |
533 | } |
534 | ||
535 | /* | |
536 | * vm_object_deactivate_pages | |
537 | * | |
538 | * Deactivate all pages in the specified object. (Keep its pages | |
539 | * in memory even though it is no longer referenced.) | |
540 | * | |
541 | * The object must be locked. | |
542 | */ | |
55768178 | 543 | void |
15637ed4 RG |
544 | vm_object_deactivate_pages(object) |
545 | register vm_object_t object; | |
546 | { | |
547 | register vm_page_t p, next; | |
548 | ||
549 | p = (vm_page_t) queue_first(&object->memq); | |
550 | while (!queue_end(&object->memq, (queue_entry_t) p)) { | |
551 | next = (vm_page_t) queue_next(&p->listq); | |
552 | vm_page_lock_queues(); | |
55768178 | 553 | if ((p->flags & (PG_INACTIVE|PG_BUSY)) == 0 && |
41aefbec | 554 | (p->wire_count == 0 && p->hold_count == 0)) |
8820571b NW |
555 | vm_page_deactivate(p); /* optimisation from mach 3.0 - |
556 | * andrew@werple.apana.org.au, | |
557 | * Feb '93 | |
558 | */ | |
15637ed4 RG |
559 | vm_page_unlock_queues(); |
560 | p = next; | |
561 | } | |
562 | } | |
563 | ||
564 | /* | |
565 | * Trim the object cache to size. | |
566 | */ | |
55768178 | 567 | void |
15637ed4 RG |
568 | vm_object_cache_trim() |
569 | { | |
570 | register vm_object_t object; | |
571 | ||
572 | vm_object_cache_lock(); | |
573 | while (vm_object_cached > vm_cache_max) { | |
574 | object = (vm_object_t) queue_first(&vm_object_cached_list); | |
575 | vm_object_cache_unlock(); | |
576 | ||
577 | if (object != vm_object_lookup(object->pager)) | |
578 | panic("vm_object_deactivate: I'm sooo confused."); | |
579 | ||
580 | pager_cache(object, FALSE); | |
581 | ||
582 | vm_object_cache_lock(); | |
583 | } | |
584 | vm_object_cache_unlock(); | |
585 | } | |
586 | ||
15637ed4 RG |
587 | /* |
588 | * vm_object_shutdown() | |
589 | * | |
590 | * Shut down the object system. Unfortunately, while we | |
591 | * may be trying to do this, init is happily waiting for | |
592 | * processes to exit, and therefore will be causing some objects | |
593 | * to be deallocated. To handle this, we gain a fake reference | |
594 | * to all objects we release paging areas for. This will prevent | |
595 | * a duplicate deallocation. This routine is probably full of | |
596 | * race conditions! | |
597 | */ | |
598 | ||
55768178 DG |
599 | #if 0 |
600 | void | |
601 | vm_object_shutdown() | |
15637ed4 RG |
602 | { |
603 | register vm_object_t object; | |
604 | ||
605 | /* | |
606 | * Clean up the object cache *before* we screw up the reference | |
607 | * counts on all of the objects. | |
608 | */ | |
609 | ||
610 | vm_object_cache_clear(); | |
611 | ||
15637ed4 RG |
612 | |
613 | /* | |
614 | * First we gain a reference to each object so that | |
615 | * no one else will deallocate them. | |
616 | */ | |
617 | ||
618 | simple_lock(&vm_object_list_lock); | |
619 | object = (vm_object_t) queue_first(&vm_object_list); | |
620 | while (!queue_end(&vm_object_list, (queue_entry_t) object)) { | |
621 | vm_object_reference(object); | |
622 | object = (vm_object_t) queue_next(&object->object_list); | |
623 | } | |
624 | simple_unlock(&vm_object_list_lock); | |
625 | ||
626 | /* | |
627 | * Now we deallocate all the paging areas. We don't need | |
628 | * to lock anything because we've reduced to a single | |
629 | * processor while shutting down. This also assumes that | |
630 | * no new objects are being created. | |
631 | */ | |
632 | ||
633 | object = (vm_object_t) queue_first(&vm_object_list); | |
634 | while (!queue_end(&vm_object_list, (queue_entry_t) object)) { | |
635 | if (object->pager != NULL) | |
636 | vm_pager_deallocate(object->pager); | |
637 | object = (vm_object_t) queue_next(&object->object_list); | |
638 | printf("."); | |
639 | } | |
640 | printf("done.\n"); | |
641 | } | |
55768178 | 642 | #endif |
15637ed4 RG |
643 | /* |
644 | * vm_object_pmap_copy: | |
645 | * | |
646 | * Makes all physical pages in the specified | |
647 | * object range copy-on-write. No writeable | |
648 | * references to these pages should remain. | |
649 | * | |
650 | * The object must *not* be locked. | |
651 | */ | |
55768178 DG |
652 | void |
653 | vm_object_pmap_copy(object, start, end) | |
15637ed4 RG |
654 | register vm_object_t object; |
655 | register vm_offset_t start; | |
656 | register vm_offset_t end; | |
657 | { | |
658 | register vm_page_t p; | |
55768178 DG |
659 | vm_offset_t amount; |
660 | ||
41aefbec DG |
661 | if (object == NULL) |
662 | return; | |
663 | ||
55768178 DG |
664 | start = trunc_page(start); |
665 | end = round_page(end); | |
666 | ||
667 | amount = ((end - start) + PAGE_SIZE - 1) / PAGE_SIZE; | |
15637ed4 | 668 | |
15637ed4 RG |
669 | vm_object_lock(object); |
670 | p = (vm_page_t) queue_first(&object->memq); | |
671 | while (!queue_end(&object->memq, (queue_entry_t) p)) { | |
672 | if ((start <= p->offset) && (p->offset < end)) { | |
673 | pmap_page_protect(VM_PAGE_TO_PHYS(p), VM_PROT_READ); | |
fd76afd7 | 674 | p->flags |= PG_COPY_ON_WRITE; |
55768178 DG |
675 | amount -= 1; |
676 | if (amount <= 0) | |
677 | break; | |
15637ed4 RG |
678 | } |
679 | p = (vm_page_t) queue_next(&p->listq); | |
680 | } | |
681 | vm_object_unlock(object); | |
682 | } | |
683 | ||
684 | /* | |
685 | * vm_object_pmap_remove: | |
686 | * | |
687 | * Removes all physical pages in the specified | |
688 | * object range from all physical maps. | |
689 | * | |
690 | * The object must *not* be locked. | |
691 | */ | |
55768178 DG |
692 | void |
693 | vm_object_pmap_remove(object, start, end) | |
15637ed4 RG |
694 | register vm_object_t object; |
695 | register vm_offset_t start; | |
696 | register vm_offset_t end; | |
697 | { | |
698 | register vm_page_t p; | |
92c70781 | 699 | vm_offset_t size; |
15637ed4 RG |
700 | |
701 | if (object == NULL) | |
702 | return; | |
703 | ||
704 | vm_object_lock(object); | |
92c70781 DG |
705 | again: |
706 | size = ((end - start) + PAGE_SIZE - 1) / PAGE_SIZE; | |
15637ed4 RG |
707 | p = (vm_page_t) queue_first(&object->memq); |
708 | while (!queue_end(&object->memq, (queue_entry_t) p)) { | |
55768178 | 709 | if ((start <= p->offset) && (p->offset < end)) { |
92c70781 DG |
710 | if (p->flags & PG_BUSY) { |
711 | p->flags |= PG_WANTED; | |
712 | tsleep((caddr_t) p, PVM, "vmopmr", 0); | |
713 | goto again; | |
714 | } | |
a200ca2b | 715 | pmap_page_protect(VM_PAGE_TO_PHYS(p), VM_PROT_NONE); |
55768178 DG |
716 | if ((p->flags & PG_CLEAN) == 0) |
717 | p->flags |= PG_LAUNDRY; | |
55768178 DG |
718 | if (--size <= 0) break; |
719 | } | |
15637ed4 RG |
720 | p = (vm_page_t) queue_next(&p->listq); |
721 | } | |
722 | vm_object_unlock(object); | |
723 | } | |
724 | ||
725 | /* | |
726 | * vm_object_copy: | |
727 | * | |
728 | * Create a new object which is a copy of an existing | |
729 | * object, and mark all of the pages in the existing | |
730 | * object 'copy-on-write'. The new object has one reference. | |
731 | * Returns the new object. | |
732 | * | |
733 | * May defer the copy until later if the object is not backed | |
734 | * up by a non-default pager. | |
735 | */ | |
55768178 DG |
736 | void |
737 | vm_object_copy(src_object, src_offset, size, dst_object, dst_offset, src_needs_copy) | |
15637ed4 RG |
738 | register vm_object_t src_object; |
739 | vm_offset_t src_offset; | |
740 | vm_size_t size; | |
741 | vm_object_t *dst_object; /* OUT */ | |
742 | vm_offset_t *dst_offset; /* OUT */ | |
743 | boolean_t *src_needs_copy; /* OUT */ | |
744 | { | |
745 | register vm_object_t new_copy; | |
746 | register vm_object_t old_copy; | |
747 | vm_offset_t new_start, new_end; | |
55768178 DG |
748 | vm_offset_t src_offset_end; |
749 | vm_offset_t tmpsize; | |
15637ed4 RG |
750 | |
751 | register vm_page_t p; | |
752 | ||
753 | if (src_object == NULL) { | |
754 | /* | |
755 | * Nothing to copy | |
756 | */ | |
757 | *dst_object = NULL; | |
758 | *dst_offset = 0; | |
759 | *src_needs_copy = FALSE; | |
760 | return; | |
761 | } | |
762 | ||
763 | /* | |
764 | * If the object's pager is null_pager or the | |
765 | * default pager, we don't have to make a copy | |
766 | * of it. Instead, we set the needs copy flag and | |
767 | * make a shadow later. | |
55768178 | 768 | * DYSON: check for swap(default) pager too.... |
15637ed4 RG |
769 | */ |
770 | ||
771 | vm_object_lock(src_object); | |
45852188 | 772 | |
736d20f2 DG |
773 | /* |
774 | * Try to collapse the object before copying it. | |
775 | */ | |
736d20f2 | 776 | |
55768178 | 777 | vm_object_collapse(src_object); |
736d20f2 | 778 | |
15637ed4 | 779 | if (src_object->pager == NULL || |
55768178 DG |
780 | src_object->pager->pg_type == PG_SWAP || |
781 | src_object->internal) { | |
15637ed4 RG |
782 | |
783 | /* | |
784 | * Make another reference to the object | |
785 | */ | |
786 | src_object->ref_count++; | |
787 | ||
788 | /* | |
789 | * Mark all of the pages copy-on-write. | |
790 | */ | |
55768178 DG |
791 | tmpsize = size; |
792 | src_offset_end = src_offset + size; | |
15637ed4 | 793 | for (p = (vm_page_t) queue_first(&src_object->memq); |
55768178 | 794 | !queue_end(&src_object->memq, (queue_entry_t)p) && tmpsize > 0; |
15637ed4 RG |
795 | p = (vm_page_t) queue_next(&p->listq)) { |
796 | if (src_offset <= p->offset && | |
55768178 | 797 | p->offset < src_offset_end) { |
fd76afd7 | 798 | p->flags |= PG_COPY_ON_WRITE; |
55768178 DG |
799 | tmpsize -= PAGE_SIZE; |
800 | } | |
15637ed4 RG |
801 | } |
802 | vm_object_unlock(src_object); | |
803 | ||
804 | *dst_object = src_object; | |
805 | *dst_offset = src_offset; | |
806 | ||
807 | /* | |
808 | * Must make a shadow when write is desired | |
809 | */ | |
810 | *src_needs_copy = TRUE; | |
811 | return; | |
812 | } | |
813 | ||
15637ed4 RG |
814 | /* |
815 | * If the object has a pager, the pager wants to | |
816 | * see all of the changes. We need a copy-object | |
817 | * for the changed pages. | |
818 | * | |
819 | * If there is a copy-object, and it is empty, | |
820 | * no changes have been made to the object since the | |
821 | * copy-object was made. We can use the same copy- | |
822 | * object. | |
823 | */ | |
824 | ||
825 | Retry1: | |
826 | old_copy = src_object->copy; | |
827 | if (old_copy != NULL) { | |
828 | /* | |
829 | * Try to get the locks (out of order) | |
830 | */ | |
831 | if (!vm_object_lock_try(old_copy)) { | |
832 | vm_object_unlock(src_object); | |
833 | ||
834 | /* should spin a bit here... */ | |
835 | vm_object_lock(src_object); | |
836 | goto Retry1; | |
837 | } | |
838 | ||
839 | if (old_copy->resident_page_count == 0 && | |
840 | old_copy->pager == NULL) { | |
841 | /* | |
842 | * Return another reference to | |
843 | * the existing copy-object. | |
844 | */ | |
845 | old_copy->ref_count++; | |
846 | vm_object_unlock(old_copy); | |
847 | vm_object_unlock(src_object); | |
848 | *dst_object = old_copy; | |
849 | *dst_offset = src_offset; | |
850 | *src_needs_copy = FALSE; | |
851 | return; | |
852 | } | |
853 | vm_object_unlock(old_copy); | |
854 | } | |
855 | vm_object_unlock(src_object); | |
856 | ||
857 | /* | |
858 | * If the object has a pager, the pager wants | |
859 | * to see all of the changes. We must make | |
860 | * a copy-object and put the changed pages there. | |
861 | * | |
862 | * The copy-object is always made large enough to | |
863 | * completely shadow the original object, since | |
864 | * it may have several users who want to shadow | |
865 | * the original object at different points. | |
866 | */ | |
867 | ||
868 | new_copy = vm_object_allocate(src_object->size); | |
869 | ||
870 | Retry2: | |
871 | vm_object_lock(src_object); | |
872 | /* | |
873 | * Copy object may have changed while we were unlocked | |
874 | */ | |
875 | old_copy = src_object->copy; | |
876 | if (old_copy != NULL) { | |
877 | /* | |
878 | * Try to get the locks (out of order) | |
879 | */ | |
880 | if (!vm_object_lock_try(old_copy)) { | |
881 | vm_object_unlock(src_object); | |
882 | goto Retry2; | |
883 | } | |
884 | ||
885 | /* | |
886 | * Consistency check | |
887 | */ | |
888 | if (old_copy->shadow != src_object || | |
889 | old_copy->shadow_offset != (vm_offset_t) 0) | |
890 | panic("vm_object_copy: copy/shadow inconsistency"); | |
891 | ||
892 | /* | |
893 | * Make the old copy-object shadow the new one. | |
894 | * It will receive no more pages from the original | |
895 | * object. | |
896 | */ | |
897 | ||
898 | src_object->ref_count--; /* remove ref. from old_copy */ | |
899 | old_copy->shadow = new_copy; | |
900 | new_copy->ref_count++; /* locking not needed - we | |
901 | have the only pointer */ | |
902 | vm_object_unlock(old_copy); /* done with old_copy */ | |
903 | } | |
904 | ||
905 | new_start = (vm_offset_t) 0; /* always shadow original at 0 */ | |
906 | new_end = (vm_offset_t) new_copy->size; /* for the whole object */ | |
907 | ||
908 | /* | |
909 | * Point the new copy at the existing object. | |
910 | */ | |
911 | ||
912 | new_copy->shadow = src_object; | |
913 | new_copy->shadow_offset = new_start; | |
914 | src_object->ref_count++; | |
915 | src_object->copy = new_copy; | |
916 | ||
917 | /* | |
918 | * Mark all the affected pages of the existing object | |
919 | * copy-on-write. | |
920 | */ | |
55768178 | 921 | tmpsize = size; |
15637ed4 | 922 | p = (vm_page_t) queue_first(&src_object->memq); |
55768178 DG |
923 | while (!queue_end(&src_object->memq, (queue_entry_t) p) && tmpsize > 0) { |
924 | if ((new_start <= p->offset) && (p->offset < new_end)) { | |
fd76afd7 | 925 | p->flags |= PG_COPY_ON_WRITE; |
55768178 DG |
926 | tmpsize -= PAGE_SIZE; |
927 | } | |
15637ed4 RG |
928 | p = (vm_page_t) queue_next(&p->listq); |
929 | } | |
930 | ||
931 | vm_object_unlock(src_object); | |
932 | ||
933 | *dst_object = new_copy; | |
934 | *dst_offset = src_offset - new_start; | |
935 | *src_needs_copy = FALSE; | |
936 | } | |
937 | ||
938 | /* | |
939 | * vm_object_shadow: | |
940 | * | |
941 | * Create a new object which is backed by the | |
942 | * specified existing object range. The source | |
943 | * object reference is deallocated. | |
944 | * | |
945 | * The new object and offset into that object | |
946 | * are returned in the source parameters. | |
947 | */ | |
948 | ||
55768178 DG |
949 | void |
950 | vm_object_shadow(object, offset, length) | |
15637ed4 RG |
951 | vm_object_t *object; /* IN/OUT */ |
952 | vm_offset_t *offset; /* IN/OUT */ | |
953 | vm_size_t length; | |
954 | { | |
955 | register vm_object_t source; | |
956 | register vm_object_t result; | |
957 | ||
958 | source = *object; | |
959 | ||
960 | /* | |
961 | * Allocate a new object with the given length | |
962 | */ | |
963 | ||
964 | if ((result = vm_object_allocate(length)) == NULL) | |
965 | panic("vm_object_shadow: no object for shadowing"); | |
966 | ||
967 | /* | |
968 | * The new object shadows the source object, adding | |
969 | * a reference to it. Our caller changes his reference | |
970 | * to point to the new object, removing a reference to | |
971 | * the source object. Net result: no change of reference | |
972 | * count. | |
973 | */ | |
974 | result->shadow = source; | |
975 | ||
976 | /* | |
977 | * Store the offset into the source object, | |
978 | * and fix up the offset into the new object. | |
979 | */ | |
980 | ||
981 | result->shadow_offset = *offset; | |
982 | ||
983 | /* | |
984 | * Return the new things | |
985 | */ | |
986 | ||
987 | *offset = 0; | |
988 | *object = result; | |
989 | } | |
990 | ||
991 | /* | |
992 | * Set the specified object's pager to the specified pager. | |
993 | */ | |
994 | ||
55768178 DG |
995 | void |
996 | vm_object_setpager(object, pager, paging_offset, | |
15637ed4 RG |
997 | read_only) |
998 | vm_object_t object; | |
999 | vm_pager_t pager; | |
1000 | vm_offset_t paging_offset; | |
1001 | boolean_t read_only; | |
1002 | { | |
1003 | #ifdef lint | |
1004 | read_only++; /* No longer used */ | |
1005 | #endif lint | |
1006 | ||
1007 | vm_object_lock(object); /* XXX ? */ | |
55768178 DG |
1008 | if (object->pager && object->pager != pager) { |
1009 | panic("!!!pager already allocated!!!\n"); | |
1010 | } | |
15637ed4 RG |
1011 | object->pager = pager; |
1012 | object->paging_offset = paging_offset; | |
1013 | vm_object_unlock(object); /* XXX ? */ | |
1014 | } | |
1015 | ||
1016 | /* | |
1017 | * vm_object_hash hashes the pager/id pair. | |
1018 | */ | |
1019 | ||
1020 | #define vm_object_hash(pager) \ | |
55768178 | 1021 | ((((unsigned)pager) >> 5)%VM_OBJECT_HASH_COUNT) |
15637ed4 RG |
1022 | |
1023 | /* | |
1024 | * vm_object_lookup looks in the object cache for an object with the | |
1025 | * specified pager and paging id. | |
1026 | */ | |
1027 | ||
55768178 DG |
1028 | vm_object_t |
1029 | vm_object_lookup(pager) | |
15637ed4 RG |
1030 | vm_pager_t pager; |
1031 | { | |
1032 | register queue_t bucket; | |
1033 | register vm_object_hash_entry_t entry; | |
1034 | vm_object_t object; | |
1035 | ||
1036 | bucket = &vm_object_hashtable[vm_object_hash(pager)]; | |
1037 | ||
1038 | vm_object_cache_lock(); | |
1039 | ||
1040 | entry = (vm_object_hash_entry_t) queue_first(bucket); | |
1041 | while (!queue_end(bucket, (queue_entry_t) entry)) { | |
1042 | object = entry->object; | |
1043 | if (object->pager == pager) { | |
1044 | vm_object_lock(object); | |
1045 | if (object->ref_count == 0) { | |
1046 | queue_remove(&vm_object_cached_list, object, | |
1047 | vm_object_t, cached_list); | |
1048 | vm_object_cached--; | |
1049 | } | |
1050 | object->ref_count++; | |
1051 | vm_object_unlock(object); | |
1052 | vm_object_cache_unlock(); | |
1053 | return(object); | |
1054 | } | |
1055 | entry = (vm_object_hash_entry_t) queue_next(&entry->hash_links); | |
1056 | } | |
1057 | ||
1058 | vm_object_cache_unlock(); | |
1059 | return(NULL); | |
1060 | } | |
1061 | ||
1062 | /* | |
1063 | * vm_object_enter enters the specified object/pager/id into | |
1064 | * the hash table. | |
1065 | */ | |
1066 | ||
55768178 DG |
1067 | void |
1068 | vm_object_enter(object, pager) | |
15637ed4 RG |
1069 | vm_object_t object; |
1070 | vm_pager_t pager; | |
1071 | { | |
1072 | register queue_t bucket; | |
1073 | register vm_object_hash_entry_t entry; | |
1074 | ||
1075 | /* | |
1076 | * We don't cache null objects, and we can't cache | |
1077 | * objects with the null pager. | |
1078 | */ | |
1079 | ||
1080 | if (object == NULL) | |
1081 | return; | |
1082 | if (pager == NULL) | |
1083 | return; | |
1084 | ||
1085 | bucket = &vm_object_hashtable[vm_object_hash(pager)]; | |
1086 | entry = (vm_object_hash_entry_t) | |
1087 | malloc((u_long)sizeof *entry, M_VMOBJHASH, M_WAITOK); | |
1088 | entry->object = object; | |
1089 | object->can_persist = TRUE; | |
1090 | ||
1091 | vm_object_cache_lock(); | |
1092 | queue_enter(bucket, entry, vm_object_hash_entry_t, hash_links); | |
1093 | vm_object_cache_unlock(); | |
1094 | } | |
1095 | ||
1096 | /* | |
1097 | * vm_object_remove: | |
1098 | * | |
1099 | * Remove the pager from the hash table. | |
1100 | * Note: This assumes that the object cache | |
1101 | * is locked. XXX this should be fixed | |
1102 | * by reorganizing vm_object_deallocate. | |
1103 | */ | |
55768178 | 1104 | void |
15637ed4 RG |
1105 | vm_object_remove(pager) |
1106 | register vm_pager_t pager; | |
1107 | { | |
1108 | register queue_t bucket; | |
1109 | register vm_object_hash_entry_t entry; | |
1110 | register vm_object_t object; | |
1111 | ||
1112 | bucket = &vm_object_hashtable[vm_object_hash(pager)]; | |
1113 | ||
1114 | entry = (vm_object_hash_entry_t) queue_first(bucket); | |
1115 | while (!queue_end(bucket, (queue_entry_t) entry)) { | |
1116 | object = entry->object; | |
1117 | if (object->pager == pager) { | |
1118 | queue_remove(bucket, entry, vm_object_hash_entry_t, | |
1119 | hash_links); | |
1120 | free((caddr_t)entry, M_VMOBJHASH); | |
1121 | break; | |
1122 | } | |
1123 | entry = (vm_object_hash_entry_t) queue_next(&entry->hash_links); | |
1124 | } | |
1125 | } | |
1126 | ||
1127 | /* | |
1128 | * vm_object_cache_clear removes all objects from the cache. | |
1129 | * | |
1130 | */ | |
55768178 DG |
1131 | void |
1132 | vm_object_cache_clear() | |
15637ed4 RG |
1133 | { |
1134 | register vm_object_t object; | |
1135 | ||
1136 | /* | |
1137 | * Remove each object in the cache by scanning down the | |
1138 | * list of cached objects. | |
1139 | */ | |
1140 | vm_object_cache_lock(); | |
1141 | while (!queue_empty(&vm_object_cached_list)) { | |
1142 | object = (vm_object_t) queue_first(&vm_object_cached_list); | |
1143 | vm_object_cache_unlock(); | |
1144 | ||
1145 | /* | |
1146 | * Note: it is important that we use vm_object_lookup | |
1147 | * to gain a reference, and not vm_object_reference, because | |
1148 | * the logic for removing an object from the cache lies in | |
1149 | * lookup. | |
1150 | */ | |
1151 | if (object != vm_object_lookup(object->pager)) | |
1152 | panic("vm_object_cache_clear: I'm sooo confused."); | |
1153 | pager_cache(object, FALSE); | |
1154 | ||
1155 | vm_object_cache_lock(); | |
1156 | } | |
1157 | vm_object_cache_unlock(); | |
1158 | } | |
1159 | ||
1160 | boolean_t vm_object_collapse_allowed = TRUE; | |
1161 | /* | |
1162 | * vm_object_collapse: | |
1163 | * | |
1164 | * Collapse an object with the object backing it. | |
1165 | * Pages in the backing object are moved into the | |
1166 | * parent, and the backing object is deallocated. | |
1167 | * | |
1168 | * Requires that the object be locked and the page | |
1169 | * queues be unlocked. | |
1170 | * | |
55768178 DG |
1171 | * This routine has significant changes by John S. Dyson |
1172 | * to fix some swap memory leaks. 18 Dec 93 | |
736d20f2 | 1173 | * |
15637ed4 | 1174 | */ |
55768178 DG |
1175 | void |
1176 | vm_object_collapse(object) | |
15637ed4 RG |
1177 | register vm_object_t object; |
1178 | ||
1179 | { | |
1180 | register vm_object_t backing_object; | |
1181 | register vm_offset_t backing_offset; | |
1182 | register vm_size_t size; | |
1183 | register vm_offset_t new_offset; | |
1184 | register vm_page_t p, pp; | |
1185 | ||
1186 | if (!vm_object_collapse_allowed) | |
1187 | return; | |
1188 | ||
1189 | while (TRUE) { | |
1190 | /* | |
1191 | * Verify that the conditions are right for collapse: | |
1192 | * | |
1193 | * The object exists and no pages in it are currently | |
736d20f2 | 1194 | * being paged out. |
15637ed4 RG |
1195 | */ |
1196 | if (object == NULL || | |
736d20f2 | 1197 | object->paging_in_progress != 0) |
15637ed4 RG |
1198 | return; |
1199 | ||
1200 | /* | |
1201 | * There is a backing object, and | |
1202 | */ | |
1203 | ||
1204 | if ((backing_object = object->shadow) == NULL) | |
1205 | return; | |
1206 | ||
1207 | vm_object_lock(backing_object); | |
1208 | /* | |
1209 | * ... | |
1210 | * The backing object is not read_only, | |
1211 | * and no pages in the backing object are | |
1212 | * currently being paged out. | |
1213 | * The backing object is internal. | |
1214 | */ | |
1215 | ||
1216 | if (!backing_object->internal || | |
736d20f2 | 1217 | backing_object->paging_in_progress != 0 ) { |
15637ed4 RG |
1218 | vm_object_unlock(backing_object); |
1219 | return; | |
1220 | } | |
1221 | ||
1222 | /* | |
1223 | * The backing object can't be a copy-object: | |
1224 | * the shadow_offset for the copy-object must stay | |
1225 | * as 0. Furthermore (for the 'we have all the | |
1226 | * pages' case), if we bypass backing_object and | |
1227 | * just shadow the next object in the chain, old | |
1228 | * pages from that object would then have to be copied | |
1229 | * BOTH into the (former) backing_object and into the | |
1230 | * parent object. | |
1231 | */ | |
1232 | if (backing_object->shadow != NULL && | |
736d20f2 DG |
1233 | backing_object->shadow->copy == backing_object) { |
1234 | vm_object_unlock(backing_object); | |
1235 | return; | |
1236 | } | |
1237 | ||
1238 | /* | |
1239 | * we can deal only with the swap pager | |
1240 | */ | |
55768178 | 1241 | if ((object->pager && |
736d20f2 DG |
1242 | object->pager->pg_type != PG_SWAP) || |
1243 | (backing_object->pager && | |
1244 | backing_object->pager->pg_type != PG_SWAP)) { | |
15637ed4 RG |
1245 | vm_object_unlock(backing_object); |
1246 | return; | |
1247 | } | |
736d20f2 | 1248 | |
15637ed4 RG |
1249 | |
1250 | /* | |
1251 | * We know that we can either collapse the backing | |
1252 | * object (if the parent is the only reference to | |
1253 | * it) or (perhaps) remove the parent's reference | |
1254 | * to it. | |
1255 | */ | |
1256 | ||
1257 | backing_offset = object->shadow_offset; | |
1258 | size = object->size; | |
1259 | ||
1260 | /* | |
1261 | * If there is exactly one reference to the backing | |
1262 | * object, we can collapse it into the parent. | |
1263 | */ | |
1264 | ||
1265 | if (backing_object->ref_count == 1) { | |
1266 | ||
1267 | /* | |
1268 | * We can collapse the backing object. | |
1269 | * | |
1270 | * Move all in-memory pages from backing_object | |
1271 | * to the parent. Pages that have been paged out | |
1272 | * will be overwritten by any of the parent's | |
1273 | * pages that shadow them. | |
1274 | */ | |
1275 | ||
1276 | while (!queue_empty(&backing_object->memq)) { | |
1277 | ||
1278 | p = (vm_page_t) | |
1279 | queue_first(&backing_object->memq); | |
1280 | ||
1281 | new_offset = (p->offset - backing_offset); | |
1282 | ||
1283 | /* | |
1284 | * If the parent has a page here, or if | |
1285 | * this page falls outside the parent, | |
1286 | * dispose of it. | |
1287 | * | |
1288 | * Otherwise, move it as planned. | |
1289 | */ | |
1290 | ||
1291 | if (p->offset < backing_offset || | |
1292 | new_offset >= size) { | |
1293 | vm_page_lock_queues(); | |
1294 | vm_page_free(p); | |
1295 | vm_page_unlock_queues(); | |
1296 | } else { | |
1297 | pp = vm_page_lookup(object, new_offset); | |
55768178 DG |
1298 | if (pp != NULL || (object->pager && vm_pager_has_page(object->pager, |
1299 | object->paging_offset + new_offset))) { | |
15637ed4 RG |
1300 | vm_page_lock_queues(); |
1301 | vm_page_free(p); | |
1302 | vm_page_unlock_queues(); | |
55768178 | 1303 | } else { |
15637ed4 RG |
1304 | vm_page_rename(p, object, new_offset); |
1305 | } | |
1306 | } | |
1307 | } | |
1308 | ||
1309 | /* | |
1310 | * Move the pager from backing_object to object. | |
e475daaa JH |
1311 | */ |
1312 | ||
55768178 DG |
1313 | if (backing_object->pager) { |
1314 | backing_object->paging_in_progress++; | |
1315 | if (object->pager) { | |
1316 | vm_pager_t bopager; | |
736d20f2 | 1317 | object->paging_in_progress++; |
736d20f2 DG |
1318 | /* |
1319 | * copy shadow object pages into ours | |
1320 | * and destroy unneeded pages in shadow object. | |
1321 | */ | |
55768178 DG |
1322 | bopager = backing_object->pager; |
1323 | backing_object->pager = NULL; | |
1324 | vm_object_remove(backing_object->pager); | |
736d20f2 | 1325 | swap_pager_copy( |
55768178 | 1326 | bopager, backing_object->paging_offset, |
736d20f2 DG |
1327 | object->pager, object->paging_offset, |
1328 | object->shadow_offset); | |
1329 | object->paging_in_progress--; | |
55768178 | 1330 | if (object->paging_in_progress == 0) |
736d20f2 | 1331 | wakeup((caddr_t)object); |
736d20f2 | 1332 | } else { |
55768178 | 1333 | object->paging_in_progress++; |
736d20f2 DG |
1334 | /* |
1335 | * grab the shadow objects pager | |
1336 | */ | |
1337 | object->pager = backing_object->pager; | |
1338 | object->paging_offset = backing_object->paging_offset + backing_offset; | |
55768178 DG |
1339 | vm_object_remove(backing_object->pager); |
1340 | backing_object->pager = NULL; | |
736d20f2 DG |
1341 | /* |
1342 | * free unnecessary blocks | |
1343 | */ | |
55768178 DG |
1344 | swap_pager_freespace(object->pager, 0, object->paging_offset); |
1345 | object->paging_in_progress--; | |
1346 | if (object->paging_in_progress == 0) | |
1347 | wakeup((caddr_t)object); | |
736d20f2 | 1348 | } |
55768178 DG |
1349 | backing_object->paging_in_progress--; |
1350 | if (backing_object->paging_in_progress == 0) | |
1351 | wakeup((caddr_t)backing_object); | |
e475daaa | 1352 | } |
15637ed4 | 1353 | |
15637ed4 RG |
1354 | |
1355 | /* | |
1356 | * Object now shadows whatever backing_object did. | |
1357 | * Note that the reference to backing_object->shadow | |
1358 | * moves from within backing_object to within object. | |
1359 | */ | |
1360 | ||
1361 | object->shadow = backing_object->shadow; | |
1362 | object->shadow_offset += backing_object->shadow_offset; | |
1363 | if (object->shadow != NULL && | |
1364 | object->shadow->copy != NULL) { | |
1365 | panic("vm_object_collapse: we collapsed a copy-object!"); | |
1366 | } | |
1367 | /* | |
1368 | * Discard backing_object. | |
1369 | * | |
1370 | * Since the backing object has no pages, no | |
1371 | * pager left, and no object references within it, | |
1372 | * all that is necessary is to dispose of it. | |
1373 | */ | |
1374 | ||
1375 | vm_object_unlock(backing_object); | |
1376 | ||
1377 | simple_lock(&vm_object_list_lock); | |
1378 | queue_remove(&vm_object_list, backing_object, | |
1379 | vm_object_t, object_list); | |
1380 | vm_object_count--; | |
1381 | simple_unlock(&vm_object_list_lock); | |
1382 | ||
1383 | free((caddr_t)backing_object, M_VMOBJ); | |
1384 | ||
1385 | object_collapses++; | |
1386 | } | |
1387 | else { | |
1388 | /* | |
1389 | * If all of the pages in the backing object are | |
1390 | * shadowed by the parent object, the parent | |
1391 | * object no longer has to shadow the backing | |
1392 | * object; it can shadow the next one in the | |
1393 | * chain. | |
1394 | * | |
1395 | * The backing object must not be paged out - we'd | |
1396 | * have to check all of the paged-out pages, as | |
1397 | * well. | |
1398 | */ | |
1399 | ||
1400 | if (backing_object->pager != NULL) { | |
1401 | vm_object_unlock(backing_object); | |
1402 | return; | |
1403 | } | |
1404 | ||
1405 | /* | |
1406 | * Should have a check for a 'small' number | |
1407 | * of pages here. | |
1408 | */ | |
1409 | ||
1410 | p = (vm_page_t) queue_first(&backing_object->memq); | |
1411 | while (!queue_end(&backing_object->memq, | |
1412 | (queue_entry_t) p)) { | |
1413 | ||
1414 | new_offset = (p->offset - backing_offset); | |
1415 | ||
1416 | /* | |
1417 | * If the parent has a page here, or if | |
1418 | * this page falls outside the parent, | |
1419 | * keep going. | |
1420 | * | |
1421 | * Otherwise, the backing_object must be | |
1422 | * left in the chain. | |
1423 | */ | |
1424 | ||
1425 | if (p->offset >= backing_offset && | |
1426 | new_offset <= size && | |
55768178 DG |
1427 | ((pp = vm_page_lookup(object, new_offset)) == NULL || (pp->flags & PG_FAKE)) && |
1428 | (!object->pager || !vm_pager_has_page(object->pager, object->paging_offset+new_offset))) { | |
15637ed4 RG |
1429 | /* |
1430 | * Page still needed. | |
1431 | * Can't go any further. | |
1432 | */ | |
1433 | vm_object_unlock(backing_object); | |
1434 | return; | |
1435 | } | |
1436 | p = (vm_page_t) queue_next(&p->listq); | |
1437 | } | |
1438 | ||
1439 | /* | |
1440 | * Make the parent shadow the next object | |
1441 | * in the chain. Deallocating backing_object | |
1442 | * will not remove it, since its reference | |
1443 | * count is at least 2. | |
1444 | */ | |
1445 | ||
1446 | vm_object_reference(object->shadow = backing_object->shadow); | |
1447 | object->shadow_offset += backing_object->shadow_offset; | |
1448 | ||
8820571b NW |
1449 | #if 1 |
1450 | /* Mach 3.0 code */ | |
1451 | /* andrew@werple.apana.org.au, 12 Feb 1993 */ | |
1452 | ||
1453 | /* | |
1454 | * Backing object might have had a copy pointer | |
1455 | * to us. If it did, clear it. | |
1456 | */ | |
1457 | if (backing_object->copy == object) | |
1458 | backing_object->copy = NULL; | |
1459 | #endif | |
1460 | ||
15637ed4 RG |
1461 | /* Drop the reference count on backing_object. |
1462 | * Since its ref_count was at least 2, it | |
1463 | * will not vanish; so we don't need to call | |
1464 | * vm_object_deallocate. | |
1465 | */ | |
55768178 | 1466 | if (backing_object->ref_count == 1) |
736d20f2 | 1467 | printf("should have called obj deallocate\n"); |
15637ed4 RG |
1468 | backing_object->ref_count--; |
1469 | vm_object_unlock(backing_object); | |
1470 | ||
1471 | object_bypasses ++; | |
1472 | ||
1473 | } | |
1474 | ||
1475 | /* | |
1476 | * Try again with this object's new backing object. | |
1477 | */ | |
1478 | } | |
1479 | } | |
1480 | ||
1481 | /* | |
1482 | * vm_object_page_remove: [internal] | |
1483 | * | |
1484 | * Removes all physical pages in the specified | |
1485 | * object range from the object's list of pages. | |
1486 | * | |
1487 | * The object must be locked. | |
1488 | */ | |
55768178 DG |
1489 | void |
1490 | vm_object_page_remove(object, start, end) | |
15637ed4 RG |
1491 | register vm_object_t object; |
1492 | register vm_offset_t start; | |
1493 | register vm_offset_t end; | |
1494 | { | |
1495 | register vm_page_t p, next; | |
55768178 DG |
1496 | vm_offset_t size; |
1497 | int cnt; | |
1498 | int s; | |
15637ed4 RG |
1499 | |
1500 | if (object == NULL) | |
1501 | return; | |
1502 | ||
55768178 DG |
1503 | start = trunc_page(start); |
1504 | end = round_page(end); | |
92c70781 | 1505 | again: |
55768178 DG |
1506 | size = end-start; |
1507 | if (size > 4*PAGE_SIZE || size >= object->size/4) { | |
1508 | p = (vm_page_t) queue_first(&object->memq); | |
1509 | while (!queue_end(&object->memq, (queue_entry_t) p) && size > 0) { | |
1510 | next = (vm_page_t) queue_next(&p->listq); | |
1511 | if ((start <= p->offset) && (p->offset < end)) { | |
92c70781 DG |
1512 | if (p->flags & PG_BUSY) { |
1513 | p->flags |= PG_WANTED; | |
1514 | tsleep((caddr_t) p, PVM, "vmopar", 0); | |
1515 | goto again; | |
1516 | } | |
55768178 DG |
1517 | pmap_page_protect(VM_PAGE_TO_PHYS(p), VM_PROT_NONE); |
1518 | vm_page_lock_queues(); | |
1519 | vm_page_free(p); | |
1520 | vm_page_unlock_queues(); | |
1521 | size -= PAGE_SIZE; | |
1522 | } | |
1523 | p = next; | |
1524 | } | |
1525 | } else { | |
1526 | while (size > 0) { | |
1527 | while (p = vm_page_lookup(object, start)) { | |
92c70781 DG |
1528 | if (p->flags & PG_BUSY) { |
1529 | p->flags |= PG_WANTED; | |
1530 | tsleep((caddr_t) p, PVM, "vmopar", 0); | |
1531 | goto again; | |
1532 | } | |
55768178 DG |
1533 | pmap_page_protect(VM_PAGE_TO_PHYS(p), VM_PROT_NONE); |
1534 | vm_page_lock_queues(); | |
1535 | vm_page_free(p); | |
1536 | vm_page_unlock_queues(); | |
1537 | } | |
1538 | start += PAGE_SIZE; | |
1539 | size -= PAGE_SIZE; | |
15637ed4 | 1540 | } |
15637ed4 RG |
1541 | } |
1542 | } | |
1543 | ||
1544 | /* | |
1545 | * Routine: vm_object_coalesce | |
1546 | * Function: Coalesces two objects backing up adjoining | |
1547 | * regions of memory into a single object. | |
1548 | * | |
1549 | * returns TRUE if objects were combined. | |
1550 | * | |
1551 | * NOTE: Only works at the moment if the second object is NULL - | |
1552 | * if it's not, which object do we lock first? | |
1553 | * | |
1554 | * Parameters: | |
1555 | * prev_object First object to coalesce | |
1556 | * prev_offset Offset into prev_object | |
1557 | * next_object Second object into coalesce | |
1558 | * next_offset Offset into next_object | |
1559 | * | |
1560 | * prev_size Size of reference to prev_object | |
1561 | * next_size Size of reference to next_object | |
1562 | * | |
1563 | * Conditions: | |
1564 | * The object must *not* be locked. | |
1565 | */ | |
55768178 DG |
1566 | boolean_t |
1567 | vm_object_coalesce(prev_object, next_object, prev_offset, next_offset, prev_size, next_size) | |
15637ed4 RG |
1568 | register vm_object_t prev_object; |
1569 | vm_object_t next_object; | |
1570 | vm_offset_t prev_offset, next_offset; | |
1571 | vm_size_t prev_size, next_size; | |
1572 | { | |
1573 | vm_size_t newsize; | |
1574 | ||
1575 | #ifdef lint | |
1576 | next_offset++; | |
1577 | #endif lint | |
1578 | ||
1579 | if (next_object != NULL) { | |
1580 | return(FALSE); | |
1581 | } | |
1582 | ||
1583 | if (prev_object == NULL) { | |
1584 | return(TRUE); | |
1585 | } | |
1586 | ||
1587 | vm_object_lock(prev_object); | |
1588 | ||
1589 | /* | |
1590 | * Try to collapse the object first | |
1591 | */ | |
1592 | vm_object_collapse(prev_object); | |
1593 | ||
1594 | /* | |
1595 | * Can't coalesce if: | |
1596 | * . more than one reference | |
1597 | * . paged out | |
1598 | * . shadows another object | |
1599 | * . has a copy elsewhere | |
1600 | * (any of which mean that the pages not mapped to | |
1601 | * prev_entry may be in use anyway) | |
1602 | */ | |
15637ed4 RG |
1603 | if (prev_object->ref_count > 1 || |
1604 | prev_object->pager != NULL || | |
1605 | prev_object->shadow != NULL || | |
1606 | prev_object->copy != NULL) { | |
1607 | vm_object_unlock(prev_object); | |
1608 | return(FALSE); | |
1609 | } | |
1610 | ||
1611 | /* | |
1612 | * Remove any pages that may still be in the object from | |
1613 | * a previous deallocation. | |
1614 | */ | |
15637ed4 RG |
1615 | vm_object_page_remove(prev_object, |
1616 | prev_offset + prev_size, | |
1617 | prev_offset + prev_size + next_size); | |
1618 | ||
1619 | /* | |
1620 | * Extend the object if necessary. | |
1621 | */ | |
1622 | newsize = prev_offset + prev_size + next_size; | |
1623 | if (newsize > prev_object->size) | |
1624 | prev_object->size = newsize; | |
1625 | ||
1626 | vm_object_unlock(prev_object); | |
1627 | return(TRUE); | |
1628 | } | |
1629 | ||
55768178 DG |
1630 | /* |
1631 | * returns page after looking up in shadow chain | |
1632 | */ | |
1633 | ||
1634 | vm_page_t | |
1635 | vm_object_page_lookup(object, offset) | |
1636 | vm_object_t object; | |
1637 | vm_offset_t offset; | |
1638 | { | |
1639 | vm_page_t m; | |
1640 | if (!(m=vm_page_lookup(object, offset))) { | |
1641 | if (!object->shadow) | |
1642 | return 0; | |
1643 | else | |
1644 | return vm_object_page_lookup(object->shadow, offset + object->shadow_offset); | |
1645 | } | |
1646 | return m; | |
1647 | } | |
1648 | ||
d55b6cf4 | 1649 | #if defined(DEBUG) || (NDDB > 0) |
15637ed4 RG |
1650 | /* |
1651 | * vm_object_print: [ debug ] | |
1652 | */ | |
55768178 DG |
1653 | void |
1654 | vm_object_print(object, full) | |
15637ed4 RG |
1655 | vm_object_t object; |
1656 | boolean_t full; | |
1657 | { | |
1658 | register vm_page_t p; | |
1659 | extern indent; | |
1660 | ||
1661 | register int count; | |
1662 | ||
1663 | if (object == NULL) | |
1664 | return; | |
1665 | ||
1666 | iprintf("Object 0x%x: size=0x%x, res=%d, ref=%d, ", | |
1667 | (int) object, (int) object->size, | |
1668 | object->resident_page_count, object->ref_count); | |
1669 | printf("pager=0x%x+0x%x, shadow=(0x%x)+0x%x\n", | |
1670 | (int) object->pager, (int) object->paging_offset, | |
1671 | (int) object->shadow, (int) object->shadow_offset); | |
1672 | printf("cache: next=0x%x, prev=0x%x\n", | |
1673 | object->cached_list.next, object->cached_list.prev); | |
1674 | ||
1675 | if (!full) | |
1676 | return; | |
1677 | ||
1678 | indent += 2; | |
1679 | count = 0; | |
1680 | p = (vm_page_t) queue_first(&object->memq); | |
1681 | while (!queue_end(&object->memq, (queue_entry_t) p)) { | |
1682 | if (count == 0) | |
1683 | iprintf("memory:="); | |
1684 | else if (count == 6) { | |
1685 | printf("\n"); | |
1686 | iprintf(" ..."); | |
1687 | count = 0; | |
1688 | } else | |
1689 | printf(","); | |
1690 | count++; | |
1691 | ||
1692 | printf("(off=0x%x,page=0x%x)", p->offset, VM_PAGE_TO_PHYS(p)); | |
1693 | p = (vm_page_t) queue_next(&p->listq); | |
1694 | } | |
1695 | if (count != 0) | |
1696 | printf("\n"); | |
1697 | indent -= 2; | |
1698 | } | |
d55b6cf4 | 1699 | #endif /* defined(DEBUG) || (NDDB > 0) */ |