1 /* 2 * Copyright (c) 1991, 1993 3 * The Regents of the University of California. All rights reserved. 4 * 5 * This code is derived from software contributed to Berkeley by 6 * The Mach Operating System project at Carnegie-Mellon University. 7 * 8 * Redistribution and use in source and binary forms, with or without 9 * modification, are permitted provided that the following conditions 10 * are met: 11 * 1. Redistributions of source code must retain the above copyright 12 * notice, this list of conditions and the following disclaimer. 13 * 2. Redistributions in binary form must reproduce the above copyright 14 * notice, this list of conditions and the following disclaimer in the 15 * documentation and/or other materials provided with the distribution. 16 * 3. All advertising materials mentioning features or use of this software 17 * must display the following acknowledgement: 18 * This product includes software developed by the University of 19 * California, Berkeley and its contributors. 20 * 4. Neither the name of the University nor the names of its contributors 21 * may be used to endorse or promote products derived from this software 22 * without specific prior written permission. 23 * 24 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 25 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 26 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 27 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 28 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 29 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 30 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 31 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 32 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 33 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 34 * SUCH DAMAGE. 35 * 36 * from: @(#)vm_object.c 8.5 (Berkeley) 3/22/94 37 * 38 * 39 * Copyright (c) 1987, 1990 Carnegie-Mellon University. 40 * All rights reserved. 41 * 42 * Authors: Avadis Tevanian, Jr., Michael Wayne Young 43 * 44 * Permission to use, copy, modify and distribute this software and 45 * its documentation is hereby granted, provided that both the copyright 46 * notice and this permission notice appear in all copies of the 47 * software, derivative works or modified versions, and any portions 48 * thereof, and that both notices appear in supporting documentation. 49 * 50 * CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS" 51 * CONDITION. CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND 52 * FOR ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE. 53 * 54 * Carnegie Mellon requests users of this software to return to 55 * 56 * Software Distribution Coordinator or Software.Distribution@CS.CMU.EDU 57 * School of Computer Science 58 * Carnegie Mellon University 59 * Pittsburgh PA 15213-3890 60 * 61 * any improvements or extensions that they make and grant Carnegie the 62 * rights to redistribute these changes. 63 * 64 * $FreeBSD: src/sys/vm/vm_object.c,v 1.171.2.8 2003/05/26 19:17:56 alc Exp $ 65 * $DragonFly: src/sys/vm/vm_object.c,v 1.27 2006/12/02 23:13:46 dillon Exp $ 66 */ 67 68 /* 69 * Virtual memory object module. 70 */ 71 72 #include <sys/param.h> 73 #include <sys/systm.h> 74 #include <sys/proc.h> /* for curproc, pageproc */ 75 #include <sys/vnode.h> 76 #include <sys/vmmeter.h> 77 #include <sys/mman.h> 78 #include <sys/mount.h> 79 #include <sys/kernel.h> 80 #include <sys/sysctl.h> 81 82 #include <vm/vm.h> 83 #include <vm/vm_param.h> 84 #include <vm/pmap.h> 85 #include <vm/vm_map.h> 86 #include <vm/vm_object.h> 87 #include <vm/vm_page.h> 88 #include <vm/vm_pageout.h> 89 #include <vm/vm_pager.h> 90 #include <vm/swap_pager.h> 91 #include <vm/vm_kern.h> 92 #include <vm/vm_extern.h> 93 #include <vm/vm_zone.h> 94 95 #define EASY_SCAN_FACTOR 8 96 97 static void vm_object_qcollapse(vm_object_t object); 98 static int vm_object_page_collect_flush(vm_object_t object, vm_page_t p, 99 int pagerflags); 100 101 /* 102 * Virtual memory objects maintain the actual data 103 * associated with allocated virtual memory. A given 104 * page of memory exists within exactly one object. 105 * 106 * An object is only deallocated when all "references" 107 * are given up. Only one "reference" to a given 108 * region of an object should be writeable. 109 * 110 * Associated with each object is a list of all resident 111 * memory pages belonging to that object; this list is 112 * maintained by the "vm_page" module, and locked by the object's 113 * lock. 114 * 115 * Each object also records a "pager" routine which is 116 * used to retrieve (and store) pages to the proper backing 117 * storage. In addition, objects may be backed by other 118 * objects from which they were virtual-copied. 119 * 120 * The only items within the object structure which are 121 * modified after time of creation are: 122 * reference count locked by object's lock 123 * pager routine locked by object's lock 124 * 125 */ 126 127 struct object_q vm_object_list; 128 static long vm_object_count; /* count of all objects */ 129 vm_object_t kernel_object; 130 vm_object_t kmem_object; 131 static struct vm_object kernel_object_store; 132 static struct vm_object kmem_object_store; 133 extern int vm_pageout_page_count; 134 135 static long object_collapses; 136 static long object_bypasses; 137 static int next_index; 138 static vm_zone_t obj_zone; 139 static struct vm_zone obj_zone_store; 140 static int object_hash_rand; 141 #define VM_OBJECTS_INIT 256 142 static struct vm_object vm_objects_init[VM_OBJECTS_INIT]; 143 144 void 145 _vm_object_allocate(objtype_t type, vm_size_t size, vm_object_t object) 146 { 147 int incr; 148 RB_INIT(&object->rb_memq); 149 LIST_INIT(&object->shadow_head); 150 151 object->type = type; 152 object->size = size; 153 object->ref_count = 1; 154 object->flags = 0; 155 if ((object->type == OBJT_DEFAULT) || (object->type == OBJT_SWAP)) 156 vm_object_set_flag(object, OBJ_ONEMAPPING); 157 object->paging_in_progress = 0; 158 object->resident_page_count = 0; 159 object->shadow_count = 0; 160 object->pg_color = next_index; 161 if ( size > (PQ_L2_SIZE / 3 + PQ_PRIME1)) 162 incr = PQ_L2_SIZE / 3 + PQ_PRIME1; 163 else 164 incr = size; 165 next_index = (next_index + incr) & PQ_L2_MASK; 166 object->handle = NULL; 167 object->backing_object = NULL; 168 object->backing_object_offset = (vm_ooffset_t) 0; 169 /* 170 * Try to generate a number that will spread objects out in the 171 * hash table. We 'wipe' new objects across the hash in 128 page 172 * increments plus 1 more to offset it a little more by the time 173 * it wraps around. 174 */ 175 object->hash_rand = object_hash_rand - 129; 176 177 object->generation++; 178 179 crit_enter(); 180 TAILQ_INSERT_TAIL(&vm_object_list, object, object_list); 181 vm_object_count++; 182 object_hash_rand = object->hash_rand; 183 crit_exit(); 184 } 185 186 /* 187 * vm_object_init: 188 * 189 * Initialize the VM objects module. 190 */ 191 void 192 vm_object_init(void) 193 { 194 TAILQ_INIT(&vm_object_list); 195 196 kernel_object = &kernel_object_store; 197 _vm_object_allocate(OBJT_DEFAULT, OFF_TO_IDX(VM_MAX_KERNEL_ADDRESS - VM_MIN_KERNEL_ADDRESS), 198 kernel_object); 199 200 kmem_object = &kmem_object_store; 201 _vm_object_allocate(OBJT_DEFAULT, OFF_TO_IDX(VM_MAX_KERNEL_ADDRESS - VM_MIN_KERNEL_ADDRESS), 202 kmem_object); 203 204 obj_zone = &obj_zone_store; 205 zbootinit(obj_zone, "VM OBJECT", sizeof (struct vm_object), 206 vm_objects_init, VM_OBJECTS_INIT); 207 } 208 209 void 210 vm_object_init2(void) 211 { 212 zinitna(obj_zone, NULL, NULL, 0, 0, ZONE_PANICFAIL, 1); 213 } 214 215 /* 216 * vm_object_allocate: 217 * 218 * Returns a new object with the given size. 219 */ 220 221 vm_object_t 222 vm_object_allocate(objtype_t type, vm_size_t size) 223 { 224 vm_object_t result; 225 226 result = (vm_object_t) zalloc(obj_zone); 227 228 _vm_object_allocate(type, size, result); 229 230 return (result); 231 } 232 233 234 /* 235 * vm_object_reference: 236 * 237 * Gets another reference to the given object. 238 */ 239 void 240 vm_object_reference(vm_object_t object) 241 { 242 if (object == NULL) 243 return; 244 245 object->ref_count++; 246 if (object->type == OBJT_VNODE) { 247 vref(object->handle); 248 /* XXX what if the vnode is being destroyed? */ 249 } 250 } 251 252 static void 253 vm_object_vndeallocate(vm_object_t object) 254 { 255 struct vnode *vp = (struct vnode *) object->handle; 256 257 KASSERT(object->type == OBJT_VNODE, 258 ("vm_object_vndeallocate: not a vnode object")); 259 KASSERT(vp != NULL, ("vm_object_vndeallocate: missing vp")); 260 #ifdef INVARIANTS 261 if (object->ref_count == 0) { 262 vprint("vm_object_vndeallocate", vp); 263 panic("vm_object_vndeallocate: bad object reference count"); 264 } 265 #endif 266 267 object->ref_count--; 268 if (object->ref_count == 0) 269 vp->v_flag &= ~VTEXT; 270 vrele(vp); 271 } 272 273 /* 274 * vm_object_deallocate: 275 * 276 * Release a reference to the specified object, 277 * gained either through a vm_object_allocate 278 * or a vm_object_reference call. When all references 279 * are gone, storage associated with this object 280 * may be relinquished. 281 * 282 * No object may be locked. 283 */ 284 void 285 vm_object_deallocate(vm_object_t object) 286 { 287 vm_object_t temp; 288 289 while (object != NULL) { 290 if (object->type == OBJT_VNODE) { 291 vm_object_vndeallocate(object); 292 return; 293 } 294 295 if (object->ref_count == 0) { 296 panic("vm_object_deallocate: object deallocated too many times: %d", object->type); 297 } else if (object->ref_count > 2) { 298 object->ref_count--; 299 return; 300 } 301 302 /* 303 * Here on ref_count of one or two, which are special cases for 304 * objects. 305 */ 306 if ((object->ref_count == 2) && (object->shadow_count == 0)) { 307 vm_object_set_flag(object, OBJ_ONEMAPPING); 308 object->ref_count--; 309 return; 310 } else if ((object->ref_count == 2) && (object->shadow_count == 1)) { 311 object->ref_count--; 312 if ((object->handle == NULL) && 313 (object->type == OBJT_DEFAULT || 314 object->type == OBJT_SWAP)) { 315 vm_object_t robject; 316 317 robject = LIST_FIRST(&object->shadow_head); 318 KASSERT(robject != NULL, 319 ("vm_object_deallocate: ref_count: %d, shadow_count: %d", 320 object->ref_count, 321 object->shadow_count)); 322 if ((robject->handle == NULL) && 323 (robject->type == OBJT_DEFAULT || 324 robject->type == OBJT_SWAP)) { 325 326 robject->ref_count++; 327 328 while ( 329 robject->paging_in_progress || 330 object->paging_in_progress 331 ) { 332 vm_object_pip_sleep(robject, "objde1"); 333 vm_object_pip_sleep(object, "objde2"); 334 } 335 336 if (robject->ref_count == 1) { 337 robject->ref_count--; 338 object = robject; 339 goto doterm; 340 } 341 342 object = robject; 343 vm_object_collapse(object); 344 continue; 345 } 346 } 347 348 return; 349 350 } else { 351 object->ref_count--; 352 if (object->ref_count != 0) 353 return; 354 } 355 356 doterm: 357 358 temp = object->backing_object; 359 if (temp) { 360 LIST_REMOVE(object, shadow_list); 361 temp->shadow_count--; 362 temp->generation++; 363 object->backing_object = NULL; 364 } 365 366 /* 367 * Don't double-terminate, we could be in a termination 368 * recursion due to the terminate having to sync data 369 * to disk. 370 */ 371 if ((object->flags & OBJ_DEAD) == 0) 372 vm_object_terminate(object); 373 object = temp; 374 } 375 } 376 377 /* 378 * vm_object_terminate actually destroys the specified object, freeing 379 * up all previously used resources. 380 * 381 * The object must be locked. 382 * This routine may block. 383 */ 384 static int vm_object_terminate_callback(vm_page_t p, void *data); 385 386 void 387 vm_object_terminate(vm_object_t object) 388 { 389 /* 390 * Make sure no one uses us. 391 */ 392 vm_object_set_flag(object, OBJ_DEAD); 393 394 /* 395 * wait for the pageout daemon to be done with the object 396 */ 397 vm_object_pip_wait(object, "objtrm"); 398 399 KASSERT(!object->paging_in_progress, 400 ("vm_object_terminate: pageout in progress")); 401 402 /* 403 * Clean and free the pages, as appropriate. All references to the 404 * object are gone, so we don't need to lock it. 405 */ 406 if (object->type == OBJT_VNODE) { 407 struct vnode *vp; 408 409 /* 410 * Clean pages and flush buffers. 411 */ 412 vm_object_page_clean(object, 0, 0, OBJPC_SYNC); 413 414 vp = (struct vnode *) object->handle; 415 vinvalbuf(vp, V_SAVE, 0, 0); 416 } 417 418 /* 419 * Wait for any I/O to complete, after which there had better not 420 * be any references left on the object. 421 */ 422 vm_object_pip_wait(object, "objtrm"); 423 424 if (object->ref_count != 0) 425 panic("vm_object_terminate: object with references, ref_count=%d", object->ref_count); 426 427 /* 428 * Now free any remaining pages. For internal objects, this also 429 * removes them from paging queues. Don't free wired pages, just 430 * remove them from the object. 431 */ 432 crit_enter(); 433 vm_page_rb_tree_RB_SCAN(&object->rb_memq, NULL, 434 vm_object_terminate_callback, NULL); 435 crit_exit(); 436 437 /* 438 * Let the pager know object is dead. 439 */ 440 vm_pager_deallocate(object); 441 442 /* 443 * Remove the object from the global object list. 444 */ 445 crit_enter(); 446 TAILQ_REMOVE(&vm_object_list, object, object_list); 447 vm_object_count--; 448 crit_exit(); 449 450 wakeup(object); 451 if (object->ref_count != 0) 452 panic("vm_object_terminate2: object with references, ref_count=%d", object->ref_count); 453 454 /* 455 * Free the space for the object. 456 */ 457 zfree(obj_zone, object); 458 } 459 460 static int 461 vm_object_terminate_callback(vm_page_t p, void *data __unused) 462 { 463 if (p->busy || (p->flags & PG_BUSY)) 464 panic("vm_object_terminate: freeing busy page %p", p); 465 if (p->wire_count == 0) { 466 vm_page_busy(p); 467 vm_page_free(p); 468 mycpu->gd_cnt.v_pfree++; 469 } else { 470 vm_page_busy(p); 471 vm_page_remove(p); 472 vm_page_wakeup(p); 473 } 474 return(0); 475 } 476 477 /* 478 * vm_object_page_clean 479 * 480 * Clean all dirty pages in the specified range of object. Leaves page 481 * on whatever queue it is currently on. If NOSYNC is set then do not 482 * write out pages with PG_NOSYNC set (originally comes from MAP_NOSYNC), 483 * leaving the object dirty. 484 * 485 * When stuffing pages asynchronously, allow clustering. XXX we need a 486 * synchronous clustering mode implementation. 487 * 488 * Odd semantics: if start == end, we clean everything. 489 */ 490 static int vm_object_page_clean_pass1(struct vm_page *p, void *data); 491 static int vm_object_page_clean_pass2(struct vm_page *p, void *data); 492 493 void 494 vm_object_page_clean(vm_object_t object, vm_pindex_t start, vm_pindex_t end, 495 int flags) 496 { 497 struct rb_vm_page_scan_info info; 498 struct vnode *vp; 499 int wholescan; 500 int pagerflags; 501 int curgeneration; 502 503 if (object->type != OBJT_VNODE || 504 (object->flags & OBJ_MIGHTBEDIRTY) == 0) 505 return; 506 507 pagerflags = (flags & (OBJPC_SYNC | OBJPC_INVAL)) ? 508 VM_PAGER_PUT_SYNC : VM_PAGER_CLUSTER_OK; 509 pagerflags |= (flags & OBJPC_INVAL) ? VM_PAGER_PUT_INVAL : 0; 510 511 vp = object->handle; 512 513 /* 514 * Interlock other major object operations. This allows us to 515 * temporarily clear OBJ_WRITEABLE and OBJ_MIGHTBEDIRTY. 516 */ 517 crit_enter(); 518 vm_object_set_flag(object, OBJ_CLEANING); 519 520 /* 521 * Handle 'entire object' case 522 */ 523 info.start_pindex = start; 524 if (end == 0) { 525 info.end_pindex = object->size - 1; 526 } else { 527 info.end_pindex = end - 1; 528 } 529 wholescan = (start == 0 && info.end_pindex == object->size - 1); 530 info.limit = flags; 531 info.pagerflags = pagerflags; 532 info.object = object; 533 534 /* 535 * If cleaning the entire object do a pass to mark the pages read-only. 536 * If everything worked out ok, clear OBJ_WRITEABLE and 537 * OBJ_MIGHTBEDIRTY. 538 */ 539 if (wholescan) { 540 info.error = 0; 541 vm_page_rb_tree_RB_SCAN(&object->rb_memq, rb_vm_page_scancmp, 542 vm_object_page_clean_pass1, &info); 543 if (info.error == 0) { 544 vm_object_clear_flag(object, 545 OBJ_WRITEABLE|OBJ_MIGHTBEDIRTY); 546 if (object->type == OBJT_VNODE && 547 (vp = (struct vnode *)object->handle) != NULL) { 548 if (vp->v_flag & VOBJDIRTY) 549 vclrflags(vp, VOBJDIRTY); 550 } 551 } 552 } 553 554 /* 555 * Do a pass to clean all the dirty pages we find. 556 */ 557 do { 558 info.error = 0; 559 curgeneration = object->generation; 560 vm_page_rb_tree_RB_SCAN(&object->rb_memq, rb_vm_page_scancmp, 561 vm_object_page_clean_pass2, &info); 562 } while (info.error || curgeneration != object->generation); 563 564 vm_object_clear_flag(object, OBJ_CLEANING); 565 crit_exit(); 566 } 567 568 static 569 int 570 vm_object_page_clean_pass1(struct vm_page *p, void *data) 571 { 572 struct rb_vm_page_scan_info *info = data; 573 574 vm_page_flag_set(p, PG_CLEANCHK); 575 if ((info->limit & OBJPC_NOSYNC) && (p->flags & PG_NOSYNC)) 576 info->error = 1; 577 else 578 vm_page_protect(p, VM_PROT_READ); 579 return(0); 580 } 581 582 static 583 int 584 vm_object_page_clean_pass2(struct vm_page *p, void *data) 585 { 586 struct rb_vm_page_scan_info *info = data; 587 int n; 588 589 /* 590 * Do not mess with pages that were inserted after we started 591 * the cleaning pass. 592 */ 593 if ((p->flags & PG_CLEANCHK) == 0) 594 return(0); 595 596 /* 597 * Before wasting time traversing the pmaps, check for trivial 598 * cases where the page cannot be dirty. 599 */ 600 if (p->valid == 0 || (p->queue - p->pc) == PQ_CACHE) { 601 KKASSERT((p->dirty & p->valid) == 0); 602 return(0); 603 } 604 605 /* 606 * Check whether the page is dirty or not. The page has been set 607 * to be read-only so the check will not race a user dirtying the 608 * page. 609 */ 610 vm_page_test_dirty(p); 611 if ((p->dirty & p->valid) == 0) { 612 vm_page_flag_clear(p, PG_CLEANCHK); 613 return(0); 614 } 615 616 /* 617 * If we have been asked to skip nosync pages and this is a 618 * nosync page, skip it. Note that the object flags were 619 * not cleared in this case (because pass1 will have returned an 620 * error), so we do not have to set them. 621 */ 622 if ((info->limit & OBJPC_NOSYNC) && (p->flags & PG_NOSYNC)) { 623 vm_page_flag_clear(p, PG_CLEANCHK); 624 return(0); 625 } 626 627 /* 628 * Flush as many pages as we can. PG_CLEANCHK will be cleared on 629 * the pages that get successfully flushed. Set info->error if 630 * we raced an object modification. 631 */ 632 n = vm_object_page_collect_flush(info->object, p, info->pagerflags); 633 if (n == 0) 634 info->error = 1; 635 return(0); 636 } 637 638 /* 639 * This routine must be called within a critical section to properly avoid 640 * an interrupt unbusy/free race that can occur prior to the busy check. 641 * 642 * Using the object generation number here to detect page ripout is not 643 * the best idea in the world. XXX 644 * 645 * NOTE: we operate under the assumption that a page found to not be busy 646 * will not be ripped out from under us by an interrupt. XXX we should 647 * recode this to explicitly busy the pages. 648 */ 649 static int 650 vm_object_page_collect_flush(vm_object_t object, vm_page_t p, int pagerflags) 651 { 652 int runlen; 653 int maxf; 654 int chkb; 655 int maxb; 656 int i; 657 int curgeneration; 658 vm_pindex_t pi; 659 vm_page_t maf[vm_pageout_page_count]; 660 vm_page_t mab[vm_pageout_page_count]; 661 vm_page_t ma[vm_pageout_page_count]; 662 663 curgeneration = object->generation; 664 665 pi = p->pindex; 666 while (vm_page_sleep_busy(p, TRUE, "vpcwai")) { 667 if (object->generation != curgeneration) { 668 return(0); 669 } 670 } 671 KKASSERT(p->object == object && p->pindex == pi); 672 673 maxf = 0; 674 for(i = 1; i < vm_pageout_page_count; i++) { 675 vm_page_t tp; 676 677 if ((tp = vm_page_lookup(object, pi + i)) != NULL) { 678 if ((tp->flags & PG_BUSY) || 679 ((pagerflags & VM_PAGER_IGNORE_CLEANCHK) == 0 && 680 (tp->flags & PG_CLEANCHK) == 0) || 681 (tp->busy != 0)) 682 break; 683 if((tp->queue - tp->pc) == PQ_CACHE) { 684 vm_page_flag_clear(tp, PG_CLEANCHK); 685 break; 686 } 687 vm_page_test_dirty(tp); 688 if ((tp->dirty & tp->valid) == 0) { 689 vm_page_flag_clear(tp, PG_CLEANCHK); 690 break; 691 } 692 maf[ i - 1 ] = tp; 693 maxf++; 694 continue; 695 } 696 break; 697 } 698 699 maxb = 0; 700 chkb = vm_pageout_page_count - maxf; 701 if (chkb) { 702 for(i = 1; i < chkb;i++) { 703 vm_page_t tp; 704 705 if ((tp = vm_page_lookup(object, pi - i)) != NULL) { 706 if ((tp->flags & PG_BUSY) || 707 ((pagerflags & VM_PAGER_IGNORE_CLEANCHK) == 0 && 708 (tp->flags & PG_CLEANCHK) == 0) || 709 (tp->busy != 0)) 710 break; 711 if((tp->queue - tp->pc) == PQ_CACHE) { 712 vm_page_flag_clear(tp, PG_CLEANCHK); 713 break; 714 } 715 vm_page_test_dirty(tp); 716 if ((tp->dirty & tp->valid) == 0) { 717 vm_page_flag_clear(tp, PG_CLEANCHK); 718 break; 719 } 720 mab[ i - 1 ] = tp; 721 maxb++; 722 continue; 723 } 724 break; 725 } 726 } 727 728 for(i = 0; i < maxb; i++) { 729 int index = (maxb - i) - 1; 730 ma[index] = mab[i]; 731 vm_page_flag_clear(ma[index], PG_CLEANCHK); 732 } 733 vm_page_flag_clear(p, PG_CLEANCHK); 734 ma[maxb] = p; 735 for(i = 0; i < maxf; i++) { 736 int index = (maxb + i) + 1; 737 ma[index] = maf[i]; 738 vm_page_flag_clear(ma[index], PG_CLEANCHK); 739 } 740 runlen = maxb + maxf + 1; 741 742 vm_pageout_flush(ma, runlen, pagerflags); 743 for (i = 0; i < runlen; i++) { 744 if (ma[i]->valid & ma[i]->dirty) { 745 vm_page_protect(ma[i], VM_PROT_READ); 746 vm_page_flag_set(ma[i], PG_CLEANCHK); 747 748 /* 749 * maxf will end up being the actual number of pages 750 * we wrote out contiguously, non-inclusive of the 751 * first page. We do not count look-behind pages. 752 */ 753 if (i >= maxb + 1 && (maxf > i - maxb - 1)) 754 maxf = i - maxb - 1; 755 } 756 } 757 return(maxf + 1); 758 } 759 760 #ifdef not_used 761 /* XXX I cannot tell if this should be an exported symbol */ 762 /* 763 * vm_object_deactivate_pages 764 * 765 * Deactivate all pages in the specified object. (Keep its pages 766 * in memory even though it is no longer referenced.) 767 * 768 * The object must be locked. 769 */ 770 static int vm_object_deactivate_pages_callback(vm_page_t p, void *data); 771 772 static void 773 vm_object_deactivate_pages(vm_object_t object) 774 { 775 crit_enter(); 776 vm_page_rb_tree_RB_SCAN(&object->rb_memq, NULL, 777 vm_object_deactivate_pages_callback, NULL); 778 crit_exit(); 779 } 780 781 static int 782 vm_object_deactivate_pages_callback(vm_page_t p, void *data __unused) 783 { 784 vm_page_deactivate(p); 785 return(0); 786 } 787 788 #endif 789 790 /* 791 * Same as vm_object_pmap_copy, except range checking really 792 * works, and is meant for small sections of an object. 793 * 794 * This code protects resident pages by making them read-only 795 * and is typically called on a fork or split when a page 796 * is converted to copy-on-write. 797 * 798 * NOTE: If the page is already at VM_PROT_NONE, calling 799 * vm_page_protect will have no effect. 800 */ 801 void 802 vm_object_pmap_copy_1(vm_object_t object, vm_pindex_t start, vm_pindex_t end) 803 { 804 vm_pindex_t idx; 805 vm_page_t p; 806 807 if (object == NULL || (object->flags & OBJ_WRITEABLE) == 0) 808 return; 809 810 /* 811 * spl protection needed to prevent races between the lookup, 812 * an interrupt unbusy/free, and our protect call. 813 */ 814 crit_enter(); 815 for (idx = start; idx < end; idx++) { 816 p = vm_page_lookup(object, idx); 817 if (p == NULL) 818 continue; 819 vm_page_protect(p, VM_PROT_READ); 820 } 821 crit_exit(); 822 } 823 824 /* 825 * vm_object_pmap_remove: 826 * 827 * Removes all physical pages in the specified 828 * object range from all physical maps. 829 * 830 * The object must *not* be locked. 831 */ 832 833 static int vm_object_pmap_remove_callback(vm_page_t p, void *data); 834 835 void 836 vm_object_pmap_remove(vm_object_t object, vm_pindex_t start, vm_pindex_t end) 837 { 838 struct rb_vm_page_scan_info info; 839 840 if (object == NULL) 841 return; 842 info.start_pindex = start; 843 info.end_pindex = end - 1; 844 crit_enter(); 845 vm_page_rb_tree_RB_SCAN(&object->rb_memq, rb_vm_page_scancmp, 846 vm_object_pmap_remove_callback, &info); 847 if (start == 0 && end == object->size) 848 vm_object_clear_flag(object, OBJ_WRITEABLE); 849 crit_exit(); 850 } 851 852 static int 853 vm_object_pmap_remove_callback(vm_page_t p, void *data __unused) 854 { 855 vm_page_protect(p, VM_PROT_NONE); 856 return(0); 857 } 858 859 /* 860 * vm_object_madvise: 861 * 862 * Implements the madvise function at the object/page level. 863 * 864 * MADV_WILLNEED (any object) 865 * 866 * Activate the specified pages if they are resident. 867 * 868 * MADV_DONTNEED (any object) 869 * 870 * Deactivate the specified pages if they are resident. 871 * 872 * MADV_FREE (OBJT_DEFAULT/OBJT_SWAP objects, 873 * OBJ_ONEMAPPING only) 874 * 875 * Deactivate and clean the specified pages if they are 876 * resident. This permits the process to reuse the pages 877 * without faulting or the kernel to reclaim the pages 878 * without I/O. 879 */ 880 void 881 vm_object_madvise(vm_object_t object, vm_pindex_t pindex, int count, int advise) 882 { 883 vm_pindex_t end, tpindex; 884 vm_object_t tobject; 885 vm_page_t m; 886 887 if (object == NULL) 888 return; 889 890 end = pindex + count; 891 892 /* 893 * Locate and adjust resident pages 894 */ 895 896 for (; pindex < end; pindex += 1) { 897 relookup: 898 tobject = object; 899 tpindex = pindex; 900 shadowlookup: 901 /* 902 * MADV_FREE only operates on OBJT_DEFAULT or OBJT_SWAP pages 903 * and those pages must be OBJ_ONEMAPPING. 904 */ 905 if (advise == MADV_FREE) { 906 if ((tobject->type != OBJT_DEFAULT && 907 tobject->type != OBJT_SWAP) || 908 (tobject->flags & OBJ_ONEMAPPING) == 0) { 909 continue; 910 } 911 } 912 913 /* 914 * spl protection is required to avoid a race between the 915 * lookup, an interrupt unbusy/free, and our busy check. 916 */ 917 918 crit_enter(); 919 m = vm_page_lookup(tobject, tpindex); 920 921 if (m == NULL) { 922 /* 923 * There may be swap even if there is no backing page 924 */ 925 if (advise == MADV_FREE && tobject->type == OBJT_SWAP) 926 swap_pager_freespace(tobject, tpindex, 1); 927 928 /* 929 * next object 930 */ 931 crit_exit(); 932 if (tobject->backing_object == NULL) 933 continue; 934 tpindex += OFF_TO_IDX(tobject->backing_object_offset); 935 tobject = tobject->backing_object; 936 goto shadowlookup; 937 } 938 939 /* 940 * If the page is busy or not in a normal active state, 941 * we skip it. If the page is not managed there are no 942 * page queues to mess with. Things can break if we mess 943 * with pages in any of the below states. 944 */ 945 if ( 946 m->hold_count || 947 m->wire_count || 948 (m->flags & PG_UNMANAGED) || 949 m->valid != VM_PAGE_BITS_ALL 950 ) { 951 crit_exit(); 952 continue; 953 } 954 955 if (vm_page_sleep_busy(m, TRUE, "madvpo")) { 956 crit_exit(); 957 goto relookup; 958 } 959 crit_exit(); 960 961 /* 962 * Theoretically once a page is known not to be busy, an 963 * interrupt cannot come along and rip it out from under us. 964 */ 965 966 if (advise == MADV_WILLNEED) { 967 vm_page_activate(m); 968 } else if (advise == MADV_DONTNEED) { 969 vm_page_dontneed(m); 970 } else if (advise == MADV_FREE) { 971 /* 972 * Mark the page clean. This will allow the page 973 * to be freed up by the system. However, such pages 974 * are often reused quickly by malloc()/free() 975 * so we do not do anything that would cause 976 * a page fault if we can help it. 977 * 978 * Specifically, we do not try to actually free 979 * the page now nor do we try to put it in the 980 * cache (which would cause a page fault on reuse). 981 * 982 * But we do make the page is freeable as we 983 * can without actually taking the step of unmapping 984 * it. 985 */ 986 pmap_clear_modify(m); 987 m->dirty = 0; 988 m->act_count = 0; 989 vm_page_dontneed(m); 990 if (tobject->type == OBJT_SWAP) 991 swap_pager_freespace(tobject, tpindex, 1); 992 } 993 } 994 } 995 996 /* 997 * vm_object_shadow: 998 * 999 * Create a new object which is backed by the 1000 * specified existing object range. The source 1001 * object reference is deallocated. 1002 * 1003 * The new object and offset into that object 1004 * are returned in the source parameters. 1005 */ 1006 1007 void 1008 vm_object_shadow(vm_object_t *object, /* IN/OUT */ 1009 vm_ooffset_t *offset, /* IN/OUT */ 1010 vm_size_t length) 1011 { 1012 vm_object_t source; 1013 vm_object_t result; 1014 1015 source = *object; 1016 1017 /* 1018 * Don't create the new object if the old object isn't shared. 1019 */ 1020 1021 if (source != NULL && 1022 source->ref_count == 1 && 1023 source->handle == NULL && 1024 (source->type == OBJT_DEFAULT || 1025 source->type == OBJT_SWAP)) 1026 return; 1027 1028 /* 1029 * Allocate a new object with the given length 1030 */ 1031 1032 if ((result = vm_object_allocate(OBJT_DEFAULT, length)) == NULL) 1033 panic("vm_object_shadow: no object for shadowing"); 1034 1035 /* 1036 * The new object shadows the source object, adding a reference to it. 1037 * Our caller changes his reference to point to the new object, 1038 * removing a reference to the source object. Net result: no change 1039 * of reference count. 1040 * 1041 * Try to optimize the result object's page color when shadowing 1042 * in order to maintain page coloring consistency in the combined 1043 * shadowed object. 1044 */ 1045 result->backing_object = source; 1046 if (source) { 1047 LIST_INSERT_HEAD(&source->shadow_head, result, shadow_list); 1048 source->shadow_count++; 1049 source->generation++; 1050 result->pg_color = (source->pg_color + OFF_TO_IDX(*offset)) & PQ_L2_MASK; 1051 } 1052 1053 /* 1054 * Store the offset into the source object, and fix up the offset into 1055 * the new object. 1056 */ 1057 1058 result->backing_object_offset = *offset; 1059 1060 /* 1061 * Return the new things 1062 */ 1063 1064 *offset = 0; 1065 *object = result; 1066 } 1067 1068 #define OBSC_TEST_ALL_SHADOWED 0x0001 1069 #define OBSC_COLLAPSE_NOWAIT 0x0002 1070 #define OBSC_COLLAPSE_WAIT 0x0004 1071 1072 static int vm_object_backing_scan_callback(vm_page_t p, void *data); 1073 1074 static __inline int 1075 vm_object_backing_scan(vm_object_t object, int op) 1076 { 1077 struct rb_vm_page_scan_info info; 1078 vm_object_t backing_object; 1079 1080 /* 1081 * spl protection is required to avoid races between the memq/lookup, 1082 * an interrupt doing an unbusy/free, and our busy check. Amoung 1083 * other things. 1084 */ 1085 crit_enter(); 1086 1087 backing_object = object->backing_object; 1088 info.backing_offset_index = OFF_TO_IDX(object->backing_object_offset); 1089 1090 /* 1091 * Initial conditions 1092 */ 1093 1094 if (op & OBSC_TEST_ALL_SHADOWED) { 1095 /* 1096 * We do not want to have to test for the existence of 1097 * swap pages in the backing object. XXX but with the 1098 * new swapper this would be pretty easy to do. 1099 * 1100 * XXX what about anonymous MAP_SHARED memory that hasn't 1101 * been ZFOD faulted yet? If we do not test for this, the 1102 * shadow test may succeed! XXX 1103 */ 1104 if (backing_object->type != OBJT_DEFAULT) { 1105 crit_exit(); 1106 return(0); 1107 } 1108 } 1109 if (op & OBSC_COLLAPSE_WAIT) { 1110 KKASSERT((backing_object->flags & OBJ_DEAD) == 0); 1111 vm_object_set_flag(backing_object, OBJ_DEAD); 1112 } 1113 1114 /* 1115 * Our scan. We have to retry if a negative error code is returned, 1116 * otherwise 0 or 1 will be returned in info.error. 0 Indicates that 1117 * the scan had to be stopped because the parent does not completely 1118 * shadow the child. 1119 */ 1120 info.object = object; 1121 info.backing_object = backing_object; 1122 info.limit = op; 1123 do { 1124 info.error = 1; 1125 vm_page_rb_tree_RB_SCAN(&backing_object->rb_memq, NULL, 1126 vm_object_backing_scan_callback, 1127 &info); 1128 } while (info.error < 0); 1129 crit_exit(); 1130 return(info.error); 1131 } 1132 1133 static int 1134 vm_object_backing_scan_callback(vm_page_t p, void *data) 1135 { 1136 struct rb_vm_page_scan_info *info = data; 1137 vm_object_t backing_object; 1138 vm_object_t object; 1139 vm_pindex_t new_pindex; 1140 vm_pindex_t backing_offset_index; 1141 int op; 1142 1143 new_pindex = p->pindex - info->backing_offset_index; 1144 op = info->limit; 1145 object = info->object; 1146 backing_object = info->backing_object; 1147 backing_offset_index = info->backing_offset_index; 1148 1149 if (op & OBSC_TEST_ALL_SHADOWED) { 1150 vm_page_t pp; 1151 1152 /* 1153 * Ignore pages outside the parent object's range 1154 * and outside the parent object's mapping of the 1155 * backing object. 1156 * 1157 * note that we do not busy the backing object's 1158 * page. 1159 */ 1160 if ( 1161 p->pindex < backing_offset_index || 1162 new_pindex >= object->size 1163 ) { 1164 return(0); 1165 } 1166 1167 /* 1168 * See if the parent has the page or if the parent's 1169 * object pager has the page. If the parent has the 1170 * page but the page is not valid, the parent's 1171 * object pager must have the page. 1172 * 1173 * If this fails, the parent does not completely shadow 1174 * the object and we might as well give up now. 1175 */ 1176 1177 pp = vm_page_lookup(object, new_pindex); 1178 if ( 1179 (pp == NULL || pp->valid == 0) && 1180 !vm_pager_has_page(object, new_pindex, NULL, NULL) 1181 ) { 1182 info->error = 0; /* problemo */ 1183 return(-1); /* stop the scan */ 1184 } 1185 } 1186 1187 /* 1188 * Check for busy page 1189 */ 1190 1191 if (op & (OBSC_COLLAPSE_WAIT | OBSC_COLLAPSE_NOWAIT)) { 1192 vm_page_t pp; 1193 1194 if (op & OBSC_COLLAPSE_NOWAIT) { 1195 if ( 1196 (p->flags & PG_BUSY) || 1197 !p->valid || 1198 p->hold_count || 1199 p->wire_count || 1200 p->busy 1201 ) { 1202 return(0); 1203 } 1204 } else if (op & OBSC_COLLAPSE_WAIT) { 1205 if (vm_page_sleep_busy(p, TRUE, "vmocol")) { 1206 /* 1207 * If we slept, anything could have 1208 * happened. Ask that the scan be restarted. 1209 * 1210 * Since the object is marked dead, the 1211 * backing offset should not have changed. 1212 */ 1213 info->error = -1; 1214 return(-1); 1215 } 1216 } 1217 1218 /* 1219 * Busy the page 1220 */ 1221 vm_page_busy(p); 1222 1223 KASSERT( 1224 p->object == backing_object, 1225 ("vm_object_qcollapse(): object mismatch") 1226 ); 1227 1228 /* 1229 * Destroy any associated swap 1230 */ 1231 if (backing_object->type == OBJT_SWAP) { 1232 swap_pager_freespace( 1233 backing_object, 1234 p->pindex, 1235 1 1236 ); 1237 } 1238 1239 if ( 1240 p->pindex < backing_offset_index || 1241 new_pindex >= object->size 1242 ) { 1243 /* 1244 * Page is out of the parent object's range, we 1245 * can simply destroy it. 1246 */ 1247 vm_page_protect(p, VM_PROT_NONE); 1248 vm_page_free(p); 1249 return(0); 1250 } 1251 1252 pp = vm_page_lookup(object, new_pindex); 1253 if ( 1254 pp != NULL || 1255 vm_pager_has_page(object, new_pindex, NULL, NULL) 1256 ) { 1257 /* 1258 * page already exists in parent OR swap exists 1259 * for this location in the parent. Destroy 1260 * the original page from the backing object. 1261 * 1262 * Leave the parent's page alone 1263 */ 1264 vm_page_protect(p, VM_PROT_NONE); 1265 vm_page_free(p); 1266 return(0); 1267 } 1268 1269 /* 1270 * Page does not exist in parent, rename the 1271 * page from the backing object to the main object. 1272 * 1273 * If the page was mapped to a process, it can remain 1274 * mapped through the rename. 1275 */ 1276 if ((p->queue - p->pc) == PQ_CACHE) 1277 vm_page_deactivate(p); 1278 1279 vm_page_rename(p, object, new_pindex); 1280 /* page automatically made dirty by rename */ 1281 } 1282 return(0); 1283 } 1284 1285 /* 1286 * this version of collapse allows the operation to occur earlier and 1287 * when paging_in_progress is true for an object... This is not a complete 1288 * operation, but should plug 99.9% of the rest of the leaks. 1289 */ 1290 static void 1291 vm_object_qcollapse(vm_object_t object) 1292 { 1293 vm_object_t backing_object = object->backing_object; 1294 1295 if (backing_object->ref_count != 1) 1296 return; 1297 1298 backing_object->ref_count += 2; 1299 1300 vm_object_backing_scan(object, OBSC_COLLAPSE_NOWAIT); 1301 1302 backing_object->ref_count -= 2; 1303 } 1304 1305 /* 1306 * vm_object_collapse: 1307 * 1308 * Collapse an object with the object backing it. 1309 * Pages in the backing object are moved into the 1310 * parent, and the backing object is deallocated. 1311 */ 1312 void 1313 vm_object_collapse(vm_object_t object) 1314 { 1315 while (TRUE) { 1316 vm_object_t backing_object; 1317 1318 /* 1319 * Verify that the conditions are right for collapse: 1320 * 1321 * The object exists and the backing object exists. 1322 */ 1323 if (object == NULL) 1324 break; 1325 1326 if ((backing_object = object->backing_object) == NULL) 1327 break; 1328 1329 /* 1330 * we check the backing object first, because it is most likely 1331 * not collapsable. 1332 */ 1333 if (backing_object->handle != NULL || 1334 (backing_object->type != OBJT_DEFAULT && 1335 backing_object->type != OBJT_SWAP) || 1336 (backing_object->flags & OBJ_DEAD) || 1337 object->handle != NULL || 1338 (object->type != OBJT_DEFAULT && 1339 object->type != OBJT_SWAP) || 1340 (object->flags & OBJ_DEAD)) { 1341 break; 1342 } 1343 1344 if ( 1345 object->paging_in_progress != 0 || 1346 backing_object->paging_in_progress != 0 1347 ) { 1348 vm_object_qcollapse(object); 1349 break; 1350 } 1351 1352 /* 1353 * We know that we can either collapse the backing object (if 1354 * the parent is the only reference to it) or (perhaps) have 1355 * the parent bypass the object if the parent happens to shadow 1356 * all the resident pages in the entire backing object. 1357 * 1358 * This is ignoring pager-backed pages such as swap pages. 1359 * vm_object_backing_scan fails the shadowing test in this 1360 * case. 1361 */ 1362 1363 if (backing_object->ref_count == 1) { 1364 /* 1365 * If there is exactly one reference to the backing 1366 * object, we can collapse it into the parent. 1367 */ 1368 vm_object_backing_scan(object, OBSC_COLLAPSE_WAIT); 1369 1370 /* 1371 * Move the pager from backing_object to object. 1372 */ 1373 1374 if (backing_object->type == OBJT_SWAP) { 1375 vm_object_pip_add(backing_object, 1); 1376 1377 /* 1378 * scrap the paging_offset junk and do a 1379 * discrete copy. This also removes major 1380 * assumptions about how the swap-pager 1381 * works from where it doesn't belong. The 1382 * new swapper is able to optimize the 1383 * destroy-source case. 1384 */ 1385 1386 vm_object_pip_add(object, 1); 1387 swap_pager_copy( 1388 backing_object, 1389 object, 1390 OFF_TO_IDX(object->backing_object_offset), TRUE); 1391 vm_object_pip_wakeup(object); 1392 1393 vm_object_pip_wakeup(backing_object); 1394 } 1395 /* 1396 * Object now shadows whatever backing_object did. 1397 * Note that the reference to 1398 * backing_object->backing_object moves from within 1399 * backing_object to within object. 1400 */ 1401 1402 LIST_REMOVE(object, shadow_list); 1403 object->backing_object->shadow_count--; 1404 object->backing_object->generation++; 1405 if (backing_object->backing_object) { 1406 LIST_REMOVE(backing_object, shadow_list); 1407 backing_object->backing_object->shadow_count--; 1408 backing_object->backing_object->generation++; 1409 } 1410 object->backing_object = backing_object->backing_object; 1411 if (object->backing_object) { 1412 LIST_INSERT_HEAD( 1413 &object->backing_object->shadow_head, 1414 object, 1415 shadow_list 1416 ); 1417 object->backing_object->shadow_count++; 1418 object->backing_object->generation++; 1419 } 1420 1421 object->backing_object_offset += 1422 backing_object->backing_object_offset; 1423 1424 /* 1425 * Discard backing_object. 1426 * 1427 * Since the backing object has no pages, no pager left, 1428 * and no object references within it, all that is 1429 * necessary is to dispose of it. 1430 */ 1431 1432 KASSERT(backing_object->ref_count == 1, ("backing_object %p was somehow re-referenced during collapse!", backing_object)); 1433 KASSERT(RB_EMPTY(&backing_object->rb_memq), ("backing_object %p somehow has left over pages during collapse!", backing_object)); 1434 crit_enter(); 1435 TAILQ_REMOVE( 1436 &vm_object_list, 1437 backing_object, 1438 object_list 1439 ); 1440 vm_object_count--; 1441 crit_exit(); 1442 1443 zfree(obj_zone, backing_object); 1444 1445 object_collapses++; 1446 } else { 1447 vm_object_t new_backing_object; 1448 1449 /* 1450 * If we do not entirely shadow the backing object, 1451 * there is nothing we can do so we give up. 1452 */ 1453 1454 if (vm_object_backing_scan(object, OBSC_TEST_ALL_SHADOWED) == 0) { 1455 break; 1456 } 1457 1458 /* 1459 * Make the parent shadow the next object in the 1460 * chain. Deallocating backing_object will not remove 1461 * it, since its reference count is at least 2. 1462 */ 1463 1464 LIST_REMOVE(object, shadow_list); 1465 backing_object->shadow_count--; 1466 backing_object->generation++; 1467 1468 new_backing_object = backing_object->backing_object; 1469 if ((object->backing_object = new_backing_object) != NULL) { 1470 vm_object_reference(new_backing_object); 1471 LIST_INSERT_HEAD( 1472 &new_backing_object->shadow_head, 1473 object, 1474 shadow_list 1475 ); 1476 new_backing_object->shadow_count++; 1477 new_backing_object->generation++; 1478 object->backing_object_offset += 1479 backing_object->backing_object_offset; 1480 } 1481 1482 /* 1483 * Drop the reference count on backing_object. Since 1484 * its ref_count was at least 2, it will not vanish; 1485 * so we don't need to call vm_object_deallocate, but 1486 * we do anyway. 1487 */ 1488 vm_object_deallocate(backing_object); 1489 object_bypasses++; 1490 } 1491 1492 /* 1493 * Try again with this object's new backing object. 1494 */ 1495 } 1496 } 1497 1498 /* 1499 * vm_object_page_remove: [internal] 1500 * 1501 * Removes all physical pages in the specified 1502 * object range from the object's list of pages. 1503 */ 1504 static int vm_object_page_remove_callback(vm_page_t p, void *data); 1505 1506 void 1507 vm_object_page_remove(vm_object_t object, vm_pindex_t start, vm_pindex_t end, 1508 boolean_t clean_only) 1509 { 1510 struct rb_vm_page_scan_info info; 1511 int all; 1512 1513 /* 1514 * Degenerate cases and assertions 1515 */ 1516 if (object == NULL || object->resident_page_count == 0) 1517 return; 1518 KASSERT(object->type != OBJT_PHYS, 1519 ("attempt to remove pages from a physical object")); 1520 1521 /* 1522 * Indicate that paging is occuring on the object 1523 */ 1524 crit_enter(); 1525 vm_object_pip_add(object, 1); 1526 1527 /* 1528 * Figure out the actual removal range and whether we are removing 1529 * the entire contents of the object or not. If removing the entire 1530 * contents, be sure to get all pages, even those that might be 1531 * beyond the end of the object. 1532 */ 1533 info.start_pindex = start; 1534 if (end == 0) 1535 info.end_pindex = (vm_pindex_t)-1; 1536 else 1537 info.end_pindex = end - 1; 1538 info.limit = clean_only; 1539 all = (start == 0 && info.end_pindex >= object->size - 1); 1540 1541 /* 1542 * Loop until we are sure we have gotten them all. 1543 */ 1544 do { 1545 info.error = 0; 1546 vm_page_rb_tree_RB_SCAN(&object->rb_memq, rb_vm_page_scancmp, 1547 vm_object_page_remove_callback, &info); 1548 } while (info.error); 1549 1550 /* 1551 * Cleanup 1552 */ 1553 vm_object_pip_wakeup(object); 1554 crit_exit(); 1555 } 1556 1557 static int 1558 vm_object_page_remove_callback(vm_page_t p, void *data) 1559 { 1560 struct rb_vm_page_scan_info *info = data; 1561 1562 /* 1563 * Wired pages cannot be destroyed, but they can be invalidated 1564 * and we do so if clean_only (limit) is not set. 1565 */ 1566 if (p->wire_count != 0) { 1567 vm_page_protect(p, VM_PROT_NONE); 1568 if (info->limit == 0) 1569 p->valid = 0; 1570 return(0); 1571 } 1572 1573 /* 1574 * The busy flags are only cleared at 1575 * interrupt -- minimize the spl transitions 1576 */ 1577 1578 if (vm_page_sleep_busy(p, TRUE, "vmopar")) { 1579 info->error = 1; 1580 return(0); 1581 } 1582 1583 /* 1584 * limit is our clean_only flag. If set and the page is dirty, do 1585 * not free it. 1586 */ 1587 if (info->limit && p->valid) { 1588 vm_page_test_dirty(p); 1589 if (p->valid & p->dirty) 1590 return(0); 1591 } 1592 1593 /* 1594 * Destroy the page 1595 */ 1596 vm_page_busy(p); 1597 vm_page_protect(p, VM_PROT_NONE); 1598 vm_page_free(p); 1599 return(0); 1600 } 1601 1602 /* 1603 * Routine: vm_object_coalesce 1604 * Function: Coalesces two objects backing up adjoining 1605 * regions of memory into a single object. 1606 * 1607 * returns TRUE if objects were combined. 1608 * 1609 * NOTE: Only works at the moment if the second object is NULL - 1610 * if it's not, which object do we lock first? 1611 * 1612 * Parameters: 1613 * prev_object First object to coalesce 1614 * prev_offset Offset into prev_object 1615 * next_object Second object into coalesce 1616 * next_offset Offset into next_object 1617 * 1618 * prev_size Size of reference to prev_object 1619 * next_size Size of reference to next_object 1620 * 1621 * Conditions: 1622 * The object must *not* be locked. 1623 */ 1624 boolean_t 1625 vm_object_coalesce(vm_object_t prev_object, vm_pindex_t prev_pindex, 1626 vm_size_t prev_size, vm_size_t next_size) 1627 { 1628 vm_pindex_t next_pindex; 1629 1630 if (prev_object == NULL) { 1631 return (TRUE); 1632 } 1633 1634 if (prev_object->type != OBJT_DEFAULT && 1635 prev_object->type != OBJT_SWAP) { 1636 return (FALSE); 1637 } 1638 1639 /* 1640 * Try to collapse the object first 1641 */ 1642 vm_object_collapse(prev_object); 1643 1644 /* 1645 * Can't coalesce if: . more than one reference . paged out . shadows 1646 * another object . has a copy elsewhere (any of which mean that the 1647 * pages not mapped to prev_entry may be in use anyway) 1648 */ 1649 1650 if (prev_object->backing_object != NULL) { 1651 return (FALSE); 1652 } 1653 1654 prev_size >>= PAGE_SHIFT; 1655 next_size >>= PAGE_SHIFT; 1656 next_pindex = prev_pindex + prev_size; 1657 1658 if ((prev_object->ref_count > 1) && 1659 (prev_object->size != next_pindex)) { 1660 return (FALSE); 1661 } 1662 1663 /* 1664 * Remove any pages that may still be in the object from a previous 1665 * deallocation. 1666 */ 1667 if (next_pindex < prev_object->size) { 1668 vm_object_page_remove(prev_object, 1669 next_pindex, 1670 next_pindex + next_size, FALSE); 1671 if (prev_object->type == OBJT_SWAP) 1672 swap_pager_freespace(prev_object, 1673 next_pindex, next_size); 1674 } 1675 1676 /* 1677 * Extend the object if necessary. 1678 */ 1679 if (next_pindex + next_size > prev_object->size) 1680 prev_object->size = next_pindex + next_size; 1681 1682 return (TRUE); 1683 } 1684 1685 void 1686 vm_object_set_writeable_dirty(vm_object_t object) 1687 { 1688 struct vnode *vp; 1689 1690 vm_object_set_flag(object, OBJ_WRITEABLE|OBJ_MIGHTBEDIRTY); 1691 if (object->type == OBJT_VNODE && 1692 (vp = (struct vnode *)object->handle) != NULL) { 1693 if ((vp->v_flag & VOBJDIRTY) == 0) { 1694 vsetflags(vp, VOBJDIRTY); 1695 } 1696 } 1697 } 1698 1699 1700 1701 #include "opt_ddb.h" 1702 #ifdef DDB 1703 #include <sys/kernel.h> 1704 1705 #include <sys/cons.h> 1706 1707 #include <ddb/ddb.h> 1708 1709 static int _vm_object_in_map (vm_map_t map, vm_object_t object, 1710 vm_map_entry_t entry); 1711 static int vm_object_in_map (vm_object_t object); 1712 1713 static int 1714 _vm_object_in_map(vm_map_t map, vm_object_t object, vm_map_entry_t entry) 1715 { 1716 vm_map_t tmpm; 1717 vm_map_entry_t tmpe; 1718 vm_object_t obj; 1719 int entcount; 1720 1721 if (map == 0) 1722 return 0; 1723 if (entry == 0) { 1724 tmpe = map->header.next; 1725 entcount = map->nentries; 1726 while (entcount-- && (tmpe != &map->header)) { 1727 if( _vm_object_in_map(map, object, tmpe)) { 1728 return 1; 1729 } 1730 tmpe = tmpe->next; 1731 } 1732 return (0); 1733 } 1734 switch(entry->maptype) { 1735 case VM_MAPTYPE_SUBMAP: 1736 tmpm = entry->object.sub_map; 1737 tmpe = tmpm->header.next; 1738 entcount = tmpm->nentries; 1739 while (entcount-- && tmpe != &tmpm->header) { 1740 if( _vm_object_in_map(tmpm, object, tmpe)) { 1741 return 1; 1742 } 1743 tmpe = tmpe->next; 1744 } 1745 break; 1746 case VM_MAPTYPE_NORMAL: 1747 case VM_MAPTYPE_VPAGETABLE: 1748 obj = entry->object.vm_object; 1749 while (obj) { 1750 if (obj == object) 1751 return 1; 1752 obj = obj->backing_object; 1753 } 1754 break; 1755 default: 1756 break; 1757 } 1758 return 0; 1759 } 1760 1761 static int vm_object_in_map_callback(struct proc *p, void *data); 1762 1763 struct vm_object_in_map_info { 1764 vm_object_t object; 1765 int rv; 1766 }; 1767 1768 static int 1769 vm_object_in_map(vm_object_t object) 1770 { 1771 struct vm_object_in_map_info info; 1772 1773 info.rv = 0; 1774 info.object = object; 1775 1776 allproc_scan(vm_object_in_map_callback, &info); 1777 if (info.rv) 1778 return 1; 1779 if( _vm_object_in_map( kernel_map, object, 0)) 1780 return 1; 1781 if( _vm_object_in_map( pager_map, object, 0)) 1782 return 1; 1783 if( _vm_object_in_map( buffer_map, object, 0)) 1784 return 1; 1785 return 0; 1786 } 1787 1788 static int 1789 vm_object_in_map_callback(struct proc *p, void *data) 1790 { 1791 struct vm_object_in_map_info *info = data; 1792 1793 if (p->p_vmspace) { 1794 if (_vm_object_in_map(&p->p_vmspace->vm_map, info->object, 0)) { 1795 info->rv = 1; 1796 return -1; 1797 } 1798 } 1799 return (0); 1800 } 1801 1802 DB_SHOW_COMMAND(vmochk, vm_object_check) 1803 { 1804 vm_object_t object; 1805 1806 /* 1807 * make sure that internal objs are in a map somewhere 1808 * and none have zero ref counts. 1809 */ 1810 for (object = TAILQ_FIRST(&vm_object_list); 1811 object != NULL; 1812 object = TAILQ_NEXT(object, object_list)) { 1813 if (object->handle == NULL && 1814 (object->type == OBJT_DEFAULT || object->type == OBJT_SWAP)) { 1815 if (object->ref_count == 0) { 1816 db_printf("vmochk: internal obj has zero ref count: %ld\n", 1817 (long)object->size); 1818 } 1819 if (!vm_object_in_map(object)) { 1820 db_printf( 1821 "vmochk: internal obj is not in a map: " 1822 "ref: %d, size: %lu: 0x%lx, backing_object: %p\n", 1823 object->ref_count, (u_long)object->size, 1824 (u_long)object->size, 1825 (void *)object->backing_object); 1826 } 1827 } 1828 } 1829 } 1830 1831 /* 1832 * vm_object_print: [ debug ] 1833 */ 1834 DB_SHOW_COMMAND(object, vm_object_print_static) 1835 { 1836 /* XXX convert args. */ 1837 vm_object_t object = (vm_object_t)addr; 1838 boolean_t full = have_addr; 1839 1840 vm_page_t p; 1841 1842 /* XXX count is an (unused) arg. Avoid shadowing it. */ 1843 #define count was_count 1844 1845 int count; 1846 1847 if (object == NULL) 1848 return; 1849 1850 db_iprintf( 1851 "Object %p: type=%d, size=0x%lx, res=%d, ref=%d, flags=0x%x\n", 1852 object, (int)object->type, (u_long)object->size, 1853 object->resident_page_count, object->ref_count, object->flags); 1854 /* 1855 * XXX no %qd in kernel. Truncate object->backing_object_offset. 1856 */ 1857 db_iprintf(" sref=%d, backing_object(%d)=(%p)+0x%lx\n", 1858 object->shadow_count, 1859 object->backing_object ? object->backing_object->ref_count : 0, 1860 object->backing_object, (long)object->backing_object_offset); 1861 1862 if (!full) 1863 return; 1864 1865 db_indent += 2; 1866 count = 0; 1867 RB_FOREACH(p, vm_page_rb_tree, &object->rb_memq) { 1868 if (count == 0) 1869 db_iprintf("memory:="); 1870 else if (count == 6) { 1871 db_printf("\n"); 1872 db_iprintf(" ..."); 1873 count = 0; 1874 } else 1875 db_printf(","); 1876 count++; 1877 1878 db_printf("(off=0x%lx,page=0x%lx)", 1879 (u_long) p->pindex, (u_long) VM_PAGE_TO_PHYS(p)); 1880 } 1881 if (count != 0) 1882 db_printf("\n"); 1883 db_indent -= 2; 1884 } 1885 1886 /* XXX. */ 1887 #undef count 1888 1889 /* XXX need this non-static entry for calling from vm_map_print. */ 1890 void 1891 vm_object_print(/* db_expr_t */ long addr, 1892 boolean_t have_addr, 1893 /* db_expr_t */ long count, 1894 char *modif) 1895 { 1896 vm_object_print_static(addr, have_addr, count, modif); 1897 } 1898 1899 DB_SHOW_COMMAND(vmopag, vm_object_print_pages) 1900 { 1901 vm_object_t object; 1902 int nl = 0; 1903 int c; 1904 for (object = TAILQ_FIRST(&vm_object_list); 1905 object != NULL; 1906 object = TAILQ_NEXT(object, object_list)) { 1907 vm_pindex_t idx, fidx; 1908 vm_pindex_t osize; 1909 vm_paddr_t pa = -1, padiff; 1910 int rcount; 1911 vm_page_t m; 1912 1913 db_printf("new object: %p\n", (void *)object); 1914 if ( nl > 18) { 1915 c = cngetc(); 1916 if (c != ' ') 1917 return; 1918 nl = 0; 1919 } 1920 nl++; 1921 rcount = 0; 1922 fidx = 0; 1923 osize = object->size; 1924 if (osize > 128) 1925 osize = 128; 1926 for (idx = 0; idx < osize; idx++) { 1927 m = vm_page_lookup(object, idx); 1928 if (m == NULL) { 1929 if (rcount) { 1930 db_printf(" index(%ld)run(%d)pa(0x%lx)\n", 1931 (long)fidx, rcount, (long)pa); 1932 if ( nl > 18) { 1933 c = cngetc(); 1934 if (c != ' ') 1935 return; 1936 nl = 0; 1937 } 1938 nl++; 1939 rcount = 0; 1940 } 1941 continue; 1942 } 1943 1944 1945 if (rcount && 1946 (VM_PAGE_TO_PHYS(m) == pa + rcount * PAGE_SIZE)) { 1947 ++rcount; 1948 continue; 1949 } 1950 if (rcount) { 1951 padiff = pa + rcount * PAGE_SIZE - VM_PAGE_TO_PHYS(m); 1952 padiff >>= PAGE_SHIFT; 1953 padiff &= PQ_L2_MASK; 1954 if (padiff == 0) { 1955 pa = VM_PAGE_TO_PHYS(m) - rcount * PAGE_SIZE; 1956 ++rcount; 1957 continue; 1958 } 1959 db_printf(" index(%ld)run(%d)pa(0x%lx)", 1960 (long)fidx, rcount, (long)pa); 1961 db_printf("pd(%ld)\n", (long)padiff); 1962 if ( nl > 18) { 1963 c = cngetc(); 1964 if (c != ' ') 1965 return; 1966 nl = 0; 1967 } 1968 nl++; 1969 } 1970 fidx = idx; 1971 pa = VM_PAGE_TO_PHYS(m); 1972 rcount = 1; 1973 } 1974 if (rcount) { 1975 db_printf(" index(%ld)run(%d)pa(0x%lx)\n", 1976 (long)fidx, rcount, (long)pa); 1977 if ( nl > 18) { 1978 c = cngetc(); 1979 if (c != ' ') 1980 return; 1981 nl = 0; 1982 } 1983 nl++; 1984 } 1985 } 1986 } 1987 #endif /* DDB */ 1988