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 1.31 2007/06/08 02:00:47 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 struct vm_object kernel_object; 129 130 static long vm_object_count; /* count of all objects */ 131 extern int vm_pageout_page_count; 132 133 static long object_collapses; 134 static long object_bypasses; 135 static int next_index; 136 static vm_zone_t obj_zone; 137 static struct vm_zone obj_zone_store; 138 static int object_hash_rand; 139 #define VM_OBJECTS_INIT 256 140 static struct vm_object vm_objects_init[VM_OBJECTS_INIT]; 141 142 void 143 _vm_object_allocate(objtype_t type, vm_size_t size, vm_object_t object) 144 { 145 int incr; 146 RB_INIT(&object->rb_memq); 147 LIST_INIT(&object->shadow_head); 148 149 object->type = type; 150 object->size = size; 151 object->ref_count = 1; 152 object->flags = 0; 153 if ((object->type == OBJT_DEFAULT) || (object->type == OBJT_SWAP)) 154 vm_object_set_flag(object, OBJ_ONEMAPPING); 155 object->paging_in_progress = 0; 156 object->resident_page_count = 0; 157 object->shadow_count = 0; 158 object->pg_color = next_index; 159 if ( size > (PQ_L2_SIZE / 3 + PQ_PRIME1)) 160 incr = PQ_L2_SIZE / 3 + PQ_PRIME1; 161 else 162 incr = size; 163 next_index = (next_index + incr) & PQ_L2_MASK; 164 object->handle = NULL; 165 object->backing_object = NULL; 166 object->backing_object_offset = (vm_ooffset_t) 0; 167 /* 168 * Try to generate a number that will spread objects out in the 169 * hash table. We 'wipe' new objects across the hash in 128 page 170 * increments plus 1 more to offset it a little more by the time 171 * it wraps around. 172 */ 173 object->hash_rand = object_hash_rand - 129; 174 175 object->generation++; 176 177 crit_enter(); 178 TAILQ_INSERT_TAIL(&vm_object_list, object, object_list); 179 vm_object_count++; 180 object_hash_rand = object->hash_rand; 181 crit_exit(); 182 } 183 184 /* 185 * vm_object_init: 186 * 187 * Initialize the VM objects module. 188 */ 189 void 190 vm_object_init(void) 191 { 192 TAILQ_INIT(&vm_object_list); 193 194 _vm_object_allocate(OBJT_DEFAULT, OFF_TO_IDX(KvaEnd), 195 &kernel_object); 196 197 obj_zone = &obj_zone_store; 198 zbootinit(obj_zone, "VM OBJECT", sizeof (struct vm_object), 199 vm_objects_init, VM_OBJECTS_INIT); 200 } 201 202 void 203 vm_object_init2(void) 204 { 205 zinitna(obj_zone, NULL, NULL, 0, 0, ZONE_PANICFAIL, 1); 206 } 207 208 /* 209 * vm_object_allocate: 210 * 211 * Returns a new object with the given size. 212 */ 213 214 vm_object_t 215 vm_object_allocate(objtype_t type, vm_size_t size) 216 { 217 vm_object_t result; 218 219 result = (vm_object_t) zalloc(obj_zone); 220 221 _vm_object_allocate(type, size, result); 222 223 return (result); 224 } 225 226 227 /* 228 * vm_object_reference: 229 * 230 * Gets another reference to the given object. 231 */ 232 void 233 vm_object_reference(vm_object_t object) 234 { 235 if (object == NULL) 236 return; 237 238 object->ref_count++; 239 if (object->type == OBJT_VNODE) { 240 vref(object->handle); 241 /* XXX what if the vnode is being destroyed? */ 242 } 243 } 244 245 static void 246 vm_object_vndeallocate(vm_object_t object) 247 { 248 struct vnode *vp = (struct vnode *) object->handle; 249 250 KASSERT(object->type == OBJT_VNODE, 251 ("vm_object_vndeallocate: not a vnode object")); 252 KASSERT(vp != NULL, ("vm_object_vndeallocate: missing vp")); 253 #ifdef INVARIANTS 254 if (object->ref_count == 0) { 255 vprint("vm_object_vndeallocate", vp); 256 panic("vm_object_vndeallocate: bad object reference count"); 257 } 258 #endif 259 260 object->ref_count--; 261 if (object->ref_count == 0) 262 vp->v_flag &= ~VTEXT; 263 vrele(vp); 264 } 265 266 /* 267 * vm_object_deallocate: 268 * 269 * Release a reference to the specified object, 270 * gained either through a vm_object_allocate 271 * or a vm_object_reference call. When all references 272 * are gone, storage associated with this object 273 * may be relinquished. 274 * 275 * No object may be locked. 276 */ 277 void 278 vm_object_deallocate(vm_object_t object) 279 { 280 vm_object_t temp; 281 282 while (object != NULL) { 283 if (object->type == OBJT_VNODE) { 284 vm_object_vndeallocate(object); 285 return; 286 } 287 288 if (object->ref_count == 0) { 289 panic("vm_object_deallocate: object deallocated too many times: %d", object->type); 290 } else if (object->ref_count > 2) { 291 object->ref_count--; 292 return; 293 } 294 295 /* 296 * Here on ref_count of one or two, which are special cases for 297 * objects. 298 */ 299 if ((object->ref_count == 2) && (object->shadow_count == 0)) { 300 vm_object_set_flag(object, OBJ_ONEMAPPING); 301 object->ref_count--; 302 return; 303 } else if ((object->ref_count == 2) && (object->shadow_count == 1)) { 304 object->ref_count--; 305 if ((object->handle == NULL) && 306 (object->type == OBJT_DEFAULT || 307 object->type == OBJT_SWAP)) { 308 vm_object_t robject; 309 310 robject = LIST_FIRST(&object->shadow_head); 311 KASSERT(robject != NULL, 312 ("vm_object_deallocate: ref_count: %d, shadow_count: %d", 313 object->ref_count, 314 object->shadow_count)); 315 if ((robject->handle == NULL) && 316 (robject->type == OBJT_DEFAULT || 317 robject->type == OBJT_SWAP)) { 318 319 robject->ref_count++; 320 321 while ( 322 robject->paging_in_progress || 323 object->paging_in_progress 324 ) { 325 vm_object_pip_sleep(robject, "objde1"); 326 vm_object_pip_sleep(object, "objde2"); 327 } 328 329 if (robject->ref_count == 1) { 330 robject->ref_count--; 331 object = robject; 332 goto doterm; 333 } 334 335 object = robject; 336 vm_object_collapse(object); 337 continue; 338 } 339 } 340 341 return; 342 343 } else { 344 object->ref_count--; 345 if (object->ref_count != 0) 346 return; 347 } 348 349 doterm: 350 351 temp = object->backing_object; 352 if (temp) { 353 LIST_REMOVE(object, shadow_list); 354 temp->shadow_count--; 355 temp->generation++; 356 object->backing_object = NULL; 357 } 358 359 /* 360 * Don't double-terminate, we could be in a termination 361 * recursion due to the terminate having to sync data 362 * to disk. 363 */ 364 if ((object->flags & OBJ_DEAD) == 0) 365 vm_object_terminate(object); 366 object = temp; 367 } 368 } 369 370 /* 371 * vm_object_terminate actually destroys the specified object, freeing 372 * up all previously used resources. 373 * 374 * The object must be locked. 375 * This routine may block. 376 */ 377 static int vm_object_terminate_callback(vm_page_t p, void *data); 378 379 void 380 vm_object_terminate(vm_object_t object) 381 { 382 /* 383 * Make sure no one uses us. 384 */ 385 vm_object_set_flag(object, OBJ_DEAD); 386 387 /* 388 * wait for the pageout daemon to be done with the object 389 */ 390 vm_object_pip_wait(object, "objtrm"); 391 392 KASSERT(!object->paging_in_progress, 393 ("vm_object_terminate: pageout in progress")); 394 395 /* 396 * Clean and free the pages, as appropriate. All references to the 397 * object are gone, so we don't need to lock it. 398 */ 399 if (object->type == OBJT_VNODE) { 400 struct vnode *vp; 401 402 /* 403 * Clean pages and flush buffers. 404 */ 405 vm_object_page_clean(object, 0, 0, OBJPC_SYNC); 406 407 vp = (struct vnode *) object->handle; 408 vinvalbuf(vp, V_SAVE, 0, 0); 409 } 410 411 /* 412 * Wait for any I/O to complete, after which there had better not 413 * be any references left on the object. 414 */ 415 vm_object_pip_wait(object, "objtrm"); 416 417 if (object->ref_count != 0) 418 panic("vm_object_terminate: object with references, ref_count=%d", object->ref_count); 419 420 /* 421 * Now free any remaining pages. For internal objects, this also 422 * removes them from paging queues. Don't free wired pages, just 423 * remove them from the object. 424 */ 425 crit_enter(); 426 vm_page_rb_tree_RB_SCAN(&object->rb_memq, NULL, 427 vm_object_terminate_callback, NULL); 428 crit_exit(); 429 430 /* 431 * Let the pager know object is dead. 432 */ 433 vm_pager_deallocate(object); 434 435 /* 436 * Remove the object from the global object list. 437 */ 438 crit_enter(); 439 TAILQ_REMOVE(&vm_object_list, object, object_list); 440 vm_object_count--; 441 crit_exit(); 442 443 vm_object_dead_wakeup(object); 444 if (object->ref_count != 0) 445 panic("vm_object_terminate2: object with references, ref_count=%d", object->ref_count); 446 447 /* 448 * Free the space for the object. 449 */ 450 zfree(obj_zone, object); 451 } 452 453 static int 454 vm_object_terminate_callback(vm_page_t p, void *data __unused) 455 { 456 if (p->busy || (p->flags & PG_BUSY)) 457 panic("vm_object_terminate: freeing busy page %p", p); 458 if (p->wire_count == 0) { 459 vm_page_busy(p); 460 vm_page_free(p); 461 mycpu->gd_cnt.v_pfree++; 462 } else { 463 if (p->queue != PQ_NONE) 464 kprintf("vm_object_terminate: Warning: Encountered wired page %p on queue %d\n", p, p->queue); 465 vm_page_busy(p); 466 vm_page_remove(p); 467 vm_page_wakeup(p); 468 } 469 return(0); 470 } 471 472 /* 473 * The object is dead but still has an object<->pager association. Sleep 474 * and return. The caller typically retests the association in a loop. 475 */ 476 void 477 vm_object_dead_sleep(vm_object_t object, const char *wmesg) 478 { 479 crit_enter(); 480 if (object->handle) { 481 vm_object_set_flag(object, OBJ_DEADWNT); 482 tsleep(object, 0, wmesg, 0); 483 } 484 crit_exit(); 485 } 486 487 /* 488 * Wakeup anyone waiting for the object<->pager disassociation on 489 * a dead object. 490 */ 491 void 492 vm_object_dead_wakeup(vm_object_t object) 493 { 494 if (object->flags & OBJ_DEADWNT) { 495 vm_object_clear_flag(object, OBJ_DEADWNT); 496 wakeup(object); 497 } 498 } 499 500 /* 501 * vm_object_page_clean 502 * 503 * Clean all dirty pages in the specified range of object. Leaves page 504 * on whatever queue it is currently on. If NOSYNC is set then do not 505 * write out pages with PG_NOSYNC set (originally comes from MAP_NOSYNC), 506 * leaving the object dirty. 507 * 508 * When stuffing pages asynchronously, allow clustering. XXX we need a 509 * synchronous clustering mode implementation. 510 * 511 * Odd semantics: if start == end, we clean everything. 512 */ 513 static int vm_object_page_clean_pass1(struct vm_page *p, void *data); 514 static int vm_object_page_clean_pass2(struct vm_page *p, void *data); 515 516 void 517 vm_object_page_clean(vm_object_t object, vm_pindex_t start, vm_pindex_t end, 518 int flags) 519 { 520 struct rb_vm_page_scan_info info; 521 struct vnode *vp; 522 int wholescan; 523 int pagerflags; 524 int curgeneration; 525 526 if (object->type != OBJT_VNODE || 527 (object->flags & OBJ_MIGHTBEDIRTY) == 0) 528 return; 529 530 pagerflags = (flags & (OBJPC_SYNC | OBJPC_INVAL)) ? 531 VM_PAGER_PUT_SYNC : VM_PAGER_CLUSTER_OK; 532 pagerflags |= (flags & OBJPC_INVAL) ? VM_PAGER_PUT_INVAL : 0; 533 534 vp = object->handle; 535 536 /* 537 * Interlock other major object operations. This allows us to 538 * temporarily clear OBJ_WRITEABLE and OBJ_MIGHTBEDIRTY. 539 */ 540 crit_enter(); 541 vm_object_set_flag(object, OBJ_CLEANING); 542 543 /* 544 * Handle 'entire object' case 545 */ 546 info.start_pindex = start; 547 if (end == 0) { 548 info.end_pindex = object->size - 1; 549 } else { 550 info.end_pindex = end - 1; 551 } 552 wholescan = (start == 0 && info.end_pindex == object->size - 1); 553 info.limit = flags; 554 info.pagerflags = pagerflags; 555 info.object = object; 556 557 /* 558 * If cleaning the entire object do a pass to mark the pages read-only. 559 * If everything worked out ok, clear OBJ_WRITEABLE and 560 * OBJ_MIGHTBEDIRTY. 561 */ 562 if (wholescan) { 563 info.error = 0; 564 vm_page_rb_tree_RB_SCAN(&object->rb_memq, rb_vm_page_scancmp, 565 vm_object_page_clean_pass1, &info); 566 if (info.error == 0) { 567 vm_object_clear_flag(object, 568 OBJ_WRITEABLE|OBJ_MIGHTBEDIRTY); 569 if (object->type == OBJT_VNODE && 570 (vp = (struct vnode *)object->handle) != NULL) { 571 if (vp->v_flag & VOBJDIRTY) 572 vclrflags(vp, VOBJDIRTY); 573 } 574 } 575 } 576 577 /* 578 * Do a pass to clean all the dirty pages we find. 579 */ 580 do { 581 info.error = 0; 582 curgeneration = object->generation; 583 vm_page_rb_tree_RB_SCAN(&object->rb_memq, rb_vm_page_scancmp, 584 vm_object_page_clean_pass2, &info); 585 } while (info.error || curgeneration != object->generation); 586 587 vm_object_clear_flag(object, OBJ_CLEANING); 588 crit_exit(); 589 } 590 591 static 592 int 593 vm_object_page_clean_pass1(struct vm_page *p, void *data) 594 { 595 struct rb_vm_page_scan_info *info = data; 596 597 vm_page_flag_set(p, PG_CLEANCHK); 598 if ((info->limit & OBJPC_NOSYNC) && (p->flags & PG_NOSYNC)) 599 info->error = 1; 600 else 601 vm_page_protect(p, VM_PROT_READ); 602 return(0); 603 } 604 605 static 606 int 607 vm_object_page_clean_pass2(struct vm_page *p, void *data) 608 { 609 struct rb_vm_page_scan_info *info = data; 610 int n; 611 612 /* 613 * Do not mess with pages that were inserted after we started 614 * the cleaning pass. 615 */ 616 if ((p->flags & PG_CLEANCHK) == 0) 617 return(0); 618 619 /* 620 * Before wasting time traversing the pmaps, check for trivial 621 * cases where the page cannot be dirty. 622 */ 623 if (p->valid == 0 || (p->queue - p->pc) == PQ_CACHE) { 624 KKASSERT((p->dirty & p->valid) == 0); 625 return(0); 626 } 627 628 /* 629 * Check whether the page is dirty or not. The page has been set 630 * to be read-only so the check will not race a user dirtying the 631 * page. 632 */ 633 vm_page_test_dirty(p); 634 if ((p->dirty & p->valid) == 0) { 635 vm_page_flag_clear(p, PG_CLEANCHK); 636 return(0); 637 } 638 639 /* 640 * If we have been asked to skip nosync pages and this is a 641 * nosync page, skip it. Note that the object flags were 642 * not cleared in this case (because pass1 will have returned an 643 * error), so we do not have to set them. 644 */ 645 if ((info->limit & OBJPC_NOSYNC) && (p->flags & PG_NOSYNC)) { 646 vm_page_flag_clear(p, PG_CLEANCHK); 647 return(0); 648 } 649 650 /* 651 * Flush as many pages as we can. PG_CLEANCHK will be cleared on 652 * the pages that get successfully flushed. Set info->error if 653 * we raced an object modification. 654 */ 655 n = vm_object_page_collect_flush(info->object, p, info->pagerflags); 656 if (n == 0) 657 info->error = 1; 658 return(0); 659 } 660 661 /* 662 * This routine must be called within a critical section to properly avoid 663 * an interrupt unbusy/free race that can occur prior to the busy check. 664 * 665 * Using the object generation number here to detect page ripout is not 666 * the best idea in the world. XXX 667 * 668 * NOTE: we operate under the assumption that a page found to not be busy 669 * will not be ripped out from under us by an interrupt. XXX we should 670 * recode this to explicitly busy the pages. 671 */ 672 static int 673 vm_object_page_collect_flush(vm_object_t object, vm_page_t p, int pagerflags) 674 { 675 int runlen; 676 int maxf; 677 int chkb; 678 int maxb; 679 int i; 680 int curgeneration; 681 vm_pindex_t pi; 682 vm_page_t maf[vm_pageout_page_count]; 683 vm_page_t mab[vm_pageout_page_count]; 684 vm_page_t ma[vm_pageout_page_count]; 685 686 curgeneration = object->generation; 687 688 pi = p->pindex; 689 while (vm_page_sleep_busy(p, TRUE, "vpcwai")) { 690 if (object->generation != curgeneration) { 691 return(0); 692 } 693 } 694 KKASSERT(p->object == object && p->pindex == pi); 695 696 maxf = 0; 697 for(i = 1; i < vm_pageout_page_count; i++) { 698 vm_page_t tp; 699 700 if ((tp = vm_page_lookup(object, pi + i)) != NULL) { 701 if ((tp->flags & PG_BUSY) || 702 ((pagerflags & VM_PAGER_IGNORE_CLEANCHK) == 0 && 703 (tp->flags & PG_CLEANCHK) == 0) || 704 (tp->busy != 0)) 705 break; 706 if((tp->queue - tp->pc) == PQ_CACHE) { 707 vm_page_flag_clear(tp, PG_CLEANCHK); 708 break; 709 } 710 vm_page_test_dirty(tp); 711 if ((tp->dirty & tp->valid) == 0) { 712 vm_page_flag_clear(tp, PG_CLEANCHK); 713 break; 714 } 715 maf[ i - 1 ] = tp; 716 maxf++; 717 continue; 718 } 719 break; 720 } 721 722 maxb = 0; 723 chkb = vm_pageout_page_count - maxf; 724 if (chkb) { 725 for(i = 1; i < chkb;i++) { 726 vm_page_t tp; 727 728 if ((tp = vm_page_lookup(object, pi - i)) != NULL) { 729 if ((tp->flags & PG_BUSY) || 730 ((pagerflags & VM_PAGER_IGNORE_CLEANCHK) == 0 && 731 (tp->flags & PG_CLEANCHK) == 0) || 732 (tp->busy != 0)) 733 break; 734 if((tp->queue - tp->pc) == PQ_CACHE) { 735 vm_page_flag_clear(tp, PG_CLEANCHK); 736 break; 737 } 738 vm_page_test_dirty(tp); 739 if ((tp->dirty & tp->valid) == 0) { 740 vm_page_flag_clear(tp, PG_CLEANCHK); 741 break; 742 } 743 mab[ i - 1 ] = tp; 744 maxb++; 745 continue; 746 } 747 break; 748 } 749 } 750 751 for(i = 0; i < maxb; i++) { 752 int index = (maxb - i) - 1; 753 ma[index] = mab[i]; 754 vm_page_flag_clear(ma[index], PG_CLEANCHK); 755 } 756 vm_page_flag_clear(p, PG_CLEANCHK); 757 ma[maxb] = p; 758 for(i = 0; i < maxf; i++) { 759 int index = (maxb + i) + 1; 760 ma[index] = maf[i]; 761 vm_page_flag_clear(ma[index], PG_CLEANCHK); 762 } 763 runlen = maxb + maxf + 1; 764 765 vm_pageout_flush(ma, runlen, pagerflags); 766 for (i = 0; i < runlen; i++) { 767 if (ma[i]->valid & ma[i]->dirty) { 768 vm_page_protect(ma[i], VM_PROT_READ); 769 vm_page_flag_set(ma[i], PG_CLEANCHK); 770 771 /* 772 * maxf will end up being the actual number of pages 773 * we wrote out contiguously, non-inclusive of the 774 * first page. We do not count look-behind pages. 775 */ 776 if (i >= maxb + 1 && (maxf > i - maxb - 1)) 777 maxf = i - maxb - 1; 778 } 779 } 780 return(maxf + 1); 781 } 782 783 #ifdef not_used 784 /* XXX I cannot tell if this should be an exported symbol */ 785 /* 786 * vm_object_deactivate_pages 787 * 788 * Deactivate all pages in the specified object. (Keep its pages 789 * in memory even though it is no longer referenced.) 790 * 791 * The object must be locked. 792 */ 793 static int vm_object_deactivate_pages_callback(vm_page_t p, void *data); 794 795 static void 796 vm_object_deactivate_pages(vm_object_t object) 797 { 798 crit_enter(); 799 vm_page_rb_tree_RB_SCAN(&object->rb_memq, NULL, 800 vm_object_deactivate_pages_callback, NULL); 801 crit_exit(); 802 } 803 804 static int 805 vm_object_deactivate_pages_callback(vm_page_t p, void *data __unused) 806 { 807 vm_page_deactivate(p); 808 return(0); 809 } 810 811 #endif 812 813 /* 814 * Same as vm_object_pmap_copy, except range checking really 815 * works, and is meant for small sections of an object. 816 * 817 * This code protects resident pages by making them read-only 818 * and is typically called on a fork or split when a page 819 * is converted to copy-on-write. 820 * 821 * NOTE: If the page is already at VM_PROT_NONE, calling 822 * vm_page_protect will have no effect. 823 */ 824 void 825 vm_object_pmap_copy_1(vm_object_t object, vm_pindex_t start, vm_pindex_t end) 826 { 827 vm_pindex_t idx; 828 vm_page_t p; 829 830 if (object == NULL || (object->flags & OBJ_WRITEABLE) == 0) 831 return; 832 833 /* 834 * spl protection needed to prevent races between the lookup, 835 * an interrupt unbusy/free, and our protect call. 836 */ 837 crit_enter(); 838 for (idx = start; idx < end; idx++) { 839 p = vm_page_lookup(object, idx); 840 if (p == NULL) 841 continue; 842 vm_page_protect(p, VM_PROT_READ); 843 } 844 crit_exit(); 845 } 846 847 /* 848 * vm_object_pmap_remove: 849 * 850 * Removes all physical pages in the specified 851 * object range from all physical maps. 852 * 853 * The object must *not* be locked. 854 */ 855 856 static int vm_object_pmap_remove_callback(vm_page_t p, void *data); 857 858 void 859 vm_object_pmap_remove(vm_object_t object, vm_pindex_t start, vm_pindex_t end) 860 { 861 struct rb_vm_page_scan_info info; 862 863 if (object == NULL) 864 return; 865 info.start_pindex = start; 866 info.end_pindex = end - 1; 867 crit_enter(); 868 vm_page_rb_tree_RB_SCAN(&object->rb_memq, rb_vm_page_scancmp, 869 vm_object_pmap_remove_callback, &info); 870 if (start == 0 && end == object->size) 871 vm_object_clear_flag(object, OBJ_WRITEABLE); 872 crit_exit(); 873 } 874 875 static int 876 vm_object_pmap_remove_callback(vm_page_t p, void *data __unused) 877 { 878 vm_page_protect(p, VM_PROT_NONE); 879 return(0); 880 } 881 882 /* 883 * vm_object_madvise: 884 * 885 * Implements the madvise function at the object/page level. 886 * 887 * MADV_WILLNEED (any object) 888 * 889 * Activate the specified pages if they are resident. 890 * 891 * MADV_DONTNEED (any object) 892 * 893 * Deactivate the specified pages if they are resident. 894 * 895 * MADV_FREE (OBJT_DEFAULT/OBJT_SWAP objects, 896 * OBJ_ONEMAPPING only) 897 * 898 * Deactivate and clean the specified pages if they are 899 * resident. This permits the process to reuse the pages 900 * without faulting or the kernel to reclaim the pages 901 * without I/O. 902 */ 903 void 904 vm_object_madvise(vm_object_t object, vm_pindex_t pindex, int count, int advise) 905 { 906 vm_pindex_t end, tpindex; 907 vm_object_t tobject; 908 vm_page_t m; 909 910 if (object == NULL) 911 return; 912 913 end = pindex + count; 914 915 /* 916 * Locate and adjust resident pages 917 */ 918 919 for (; pindex < end; pindex += 1) { 920 relookup: 921 tobject = object; 922 tpindex = pindex; 923 shadowlookup: 924 /* 925 * MADV_FREE only operates on OBJT_DEFAULT or OBJT_SWAP pages 926 * and those pages must be OBJ_ONEMAPPING. 927 */ 928 if (advise == MADV_FREE) { 929 if ((tobject->type != OBJT_DEFAULT && 930 tobject->type != OBJT_SWAP) || 931 (tobject->flags & OBJ_ONEMAPPING) == 0) { 932 continue; 933 } 934 } 935 936 /* 937 * spl protection is required to avoid a race between the 938 * lookup, an interrupt unbusy/free, and our busy check. 939 */ 940 941 crit_enter(); 942 m = vm_page_lookup(tobject, tpindex); 943 944 if (m == NULL) { 945 /* 946 * There may be swap even if there is no backing page 947 */ 948 if (advise == MADV_FREE && tobject->type == OBJT_SWAP) 949 swap_pager_freespace(tobject, tpindex, 1); 950 951 /* 952 * next object 953 */ 954 crit_exit(); 955 if (tobject->backing_object == NULL) 956 continue; 957 tpindex += OFF_TO_IDX(tobject->backing_object_offset); 958 tobject = tobject->backing_object; 959 goto shadowlookup; 960 } 961 962 /* 963 * If the page is busy or not in a normal active state, 964 * we skip it. If the page is not managed there are no 965 * page queues to mess with. Things can break if we mess 966 * with pages in any of the below states. 967 */ 968 if ( 969 m->hold_count || 970 m->wire_count || 971 (m->flags & PG_UNMANAGED) || 972 m->valid != VM_PAGE_BITS_ALL 973 ) { 974 crit_exit(); 975 continue; 976 } 977 978 if (vm_page_sleep_busy(m, TRUE, "madvpo")) { 979 crit_exit(); 980 goto relookup; 981 } 982 crit_exit(); 983 984 /* 985 * Theoretically once a page is known not to be busy, an 986 * interrupt cannot come along and rip it out from under us. 987 */ 988 989 if (advise == MADV_WILLNEED) { 990 vm_page_activate(m); 991 } else if (advise == MADV_DONTNEED) { 992 vm_page_dontneed(m); 993 } else if (advise == MADV_FREE) { 994 /* 995 * Mark the page clean. This will allow the page 996 * to be freed up by the system. However, such pages 997 * are often reused quickly by malloc()/free() 998 * so we do not do anything that would cause 999 * a page fault if we can help it. 1000 * 1001 * Specifically, we do not try to actually free 1002 * the page now nor do we try to put it in the 1003 * cache (which would cause a page fault on reuse). 1004 * 1005 * But we do make the page is freeable as we 1006 * can without actually taking the step of unmapping 1007 * it. 1008 */ 1009 pmap_clear_modify(m); 1010 m->dirty = 0; 1011 m->act_count = 0; 1012 vm_page_dontneed(m); 1013 if (tobject->type == OBJT_SWAP) 1014 swap_pager_freespace(tobject, tpindex, 1); 1015 } 1016 } 1017 } 1018 1019 /* 1020 * vm_object_shadow: 1021 * 1022 * Create a new object which is backed by the 1023 * specified existing object range. The source 1024 * object reference is deallocated. 1025 * 1026 * The new object and offset into that object 1027 * are returned in the source parameters. 1028 */ 1029 1030 void 1031 vm_object_shadow(vm_object_t *object, /* IN/OUT */ 1032 vm_ooffset_t *offset, /* IN/OUT */ 1033 vm_size_t length) 1034 { 1035 vm_object_t source; 1036 vm_object_t result; 1037 1038 source = *object; 1039 1040 /* 1041 * Don't create the new object if the old object isn't shared. 1042 */ 1043 1044 if (source != NULL && 1045 source->ref_count == 1 && 1046 source->handle == NULL && 1047 (source->type == OBJT_DEFAULT || 1048 source->type == OBJT_SWAP)) 1049 return; 1050 1051 /* 1052 * Allocate a new object with the given length 1053 */ 1054 1055 if ((result = vm_object_allocate(OBJT_DEFAULT, length)) == NULL) 1056 panic("vm_object_shadow: no object for shadowing"); 1057 1058 /* 1059 * The new object shadows the source object, adding a reference to it. 1060 * Our caller changes his reference to point to the new object, 1061 * removing a reference to the source object. Net result: no change 1062 * of reference count. 1063 * 1064 * Try to optimize the result object's page color when shadowing 1065 * in order to maintain page coloring consistency in the combined 1066 * shadowed object. 1067 */ 1068 result->backing_object = source; 1069 if (source) { 1070 LIST_INSERT_HEAD(&source->shadow_head, result, shadow_list); 1071 source->shadow_count++; 1072 source->generation++; 1073 result->pg_color = (source->pg_color + OFF_TO_IDX(*offset)) & PQ_L2_MASK; 1074 } 1075 1076 /* 1077 * Store the offset into the source object, and fix up the offset into 1078 * the new object. 1079 */ 1080 1081 result->backing_object_offset = *offset; 1082 1083 /* 1084 * Return the new things 1085 */ 1086 1087 *offset = 0; 1088 *object = result; 1089 } 1090 1091 #define OBSC_TEST_ALL_SHADOWED 0x0001 1092 #define OBSC_COLLAPSE_NOWAIT 0x0002 1093 #define OBSC_COLLAPSE_WAIT 0x0004 1094 1095 static int vm_object_backing_scan_callback(vm_page_t p, void *data); 1096 1097 static __inline int 1098 vm_object_backing_scan(vm_object_t object, int op) 1099 { 1100 struct rb_vm_page_scan_info info; 1101 vm_object_t backing_object; 1102 1103 /* 1104 * spl protection is required to avoid races between the memq/lookup, 1105 * an interrupt doing an unbusy/free, and our busy check. Amoung 1106 * other things. 1107 */ 1108 crit_enter(); 1109 1110 backing_object = object->backing_object; 1111 info.backing_offset_index = OFF_TO_IDX(object->backing_object_offset); 1112 1113 /* 1114 * Initial conditions 1115 */ 1116 1117 if (op & OBSC_TEST_ALL_SHADOWED) { 1118 /* 1119 * We do not want to have to test for the existence of 1120 * swap pages in the backing object. XXX but with the 1121 * new swapper this would be pretty easy to do. 1122 * 1123 * XXX what about anonymous MAP_SHARED memory that hasn't 1124 * been ZFOD faulted yet? If we do not test for this, the 1125 * shadow test may succeed! XXX 1126 */ 1127 if (backing_object->type != OBJT_DEFAULT) { 1128 crit_exit(); 1129 return(0); 1130 } 1131 } 1132 if (op & OBSC_COLLAPSE_WAIT) { 1133 KKASSERT((backing_object->flags & OBJ_DEAD) == 0); 1134 vm_object_set_flag(backing_object, OBJ_DEAD); 1135 } 1136 1137 /* 1138 * Our scan. We have to retry if a negative error code is returned, 1139 * otherwise 0 or 1 will be returned in info.error. 0 Indicates that 1140 * the scan had to be stopped because the parent does not completely 1141 * shadow the child. 1142 */ 1143 info.object = object; 1144 info.backing_object = backing_object; 1145 info.limit = op; 1146 do { 1147 info.error = 1; 1148 vm_page_rb_tree_RB_SCAN(&backing_object->rb_memq, NULL, 1149 vm_object_backing_scan_callback, 1150 &info); 1151 } while (info.error < 0); 1152 crit_exit(); 1153 return(info.error); 1154 } 1155 1156 static int 1157 vm_object_backing_scan_callback(vm_page_t p, void *data) 1158 { 1159 struct rb_vm_page_scan_info *info = data; 1160 vm_object_t backing_object; 1161 vm_object_t object; 1162 vm_pindex_t new_pindex; 1163 vm_pindex_t backing_offset_index; 1164 int op; 1165 1166 new_pindex = p->pindex - info->backing_offset_index; 1167 op = info->limit; 1168 object = info->object; 1169 backing_object = info->backing_object; 1170 backing_offset_index = info->backing_offset_index; 1171 1172 if (op & OBSC_TEST_ALL_SHADOWED) { 1173 vm_page_t pp; 1174 1175 /* 1176 * Ignore pages outside the parent object's range 1177 * and outside the parent object's mapping of the 1178 * backing object. 1179 * 1180 * note that we do not busy the backing object's 1181 * page. 1182 */ 1183 if ( 1184 p->pindex < backing_offset_index || 1185 new_pindex >= object->size 1186 ) { 1187 return(0); 1188 } 1189 1190 /* 1191 * See if the parent has the page or if the parent's 1192 * object pager has the page. If the parent has the 1193 * page but the page is not valid, the parent's 1194 * object pager must have the page. 1195 * 1196 * If this fails, the parent does not completely shadow 1197 * the object and we might as well give up now. 1198 */ 1199 1200 pp = vm_page_lookup(object, new_pindex); 1201 if ( 1202 (pp == NULL || pp->valid == 0) && 1203 !vm_pager_has_page(object, new_pindex, NULL, NULL) 1204 ) { 1205 info->error = 0; /* problemo */ 1206 return(-1); /* stop the scan */ 1207 } 1208 } 1209 1210 /* 1211 * Check for busy page 1212 */ 1213 1214 if (op & (OBSC_COLLAPSE_WAIT | OBSC_COLLAPSE_NOWAIT)) { 1215 vm_page_t pp; 1216 1217 if (op & OBSC_COLLAPSE_NOWAIT) { 1218 if ( 1219 (p->flags & PG_BUSY) || 1220 !p->valid || 1221 p->hold_count || 1222 p->wire_count || 1223 p->busy 1224 ) { 1225 return(0); 1226 } 1227 } else if (op & OBSC_COLLAPSE_WAIT) { 1228 if (vm_page_sleep_busy(p, TRUE, "vmocol")) { 1229 /* 1230 * If we slept, anything could have 1231 * happened. Ask that the scan be restarted. 1232 * 1233 * Since the object is marked dead, the 1234 * backing offset should not have changed. 1235 */ 1236 info->error = -1; 1237 return(-1); 1238 } 1239 } 1240 1241 /* 1242 * Busy the page 1243 */ 1244 vm_page_busy(p); 1245 1246 KASSERT( 1247 p->object == backing_object, 1248 ("vm_object_qcollapse(): object mismatch") 1249 ); 1250 1251 /* 1252 * Destroy any associated swap 1253 */ 1254 if (backing_object->type == OBJT_SWAP) { 1255 swap_pager_freespace( 1256 backing_object, 1257 p->pindex, 1258 1 1259 ); 1260 } 1261 1262 if ( 1263 p->pindex < backing_offset_index || 1264 new_pindex >= object->size 1265 ) { 1266 /* 1267 * Page is out of the parent object's range, we 1268 * can simply destroy it. 1269 */ 1270 vm_page_protect(p, VM_PROT_NONE); 1271 vm_page_free(p); 1272 return(0); 1273 } 1274 1275 pp = vm_page_lookup(object, new_pindex); 1276 if ( 1277 pp != NULL || 1278 vm_pager_has_page(object, new_pindex, NULL, NULL) 1279 ) { 1280 /* 1281 * page already exists in parent OR swap exists 1282 * for this location in the parent. Destroy 1283 * the original page from the backing object. 1284 * 1285 * Leave the parent's page alone 1286 */ 1287 vm_page_protect(p, VM_PROT_NONE); 1288 vm_page_free(p); 1289 return(0); 1290 } 1291 1292 /* 1293 * Page does not exist in parent, rename the 1294 * page from the backing object to the main object. 1295 * 1296 * If the page was mapped to a process, it can remain 1297 * mapped through the rename. 1298 */ 1299 if ((p->queue - p->pc) == PQ_CACHE) 1300 vm_page_deactivate(p); 1301 1302 vm_page_rename(p, object, new_pindex); 1303 /* page automatically made dirty by rename */ 1304 } 1305 return(0); 1306 } 1307 1308 /* 1309 * this version of collapse allows the operation to occur earlier and 1310 * when paging_in_progress is true for an object... This is not a complete 1311 * operation, but should plug 99.9% of the rest of the leaks. 1312 */ 1313 static void 1314 vm_object_qcollapse(vm_object_t object) 1315 { 1316 vm_object_t backing_object = object->backing_object; 1317 1318 if (backing_object->ref_count != 1) 1319 return; 1320 1321 backing_object->ref_count += 2; 1322 1323 vm_object_backing_scan(object, OBSC_COLLAPSE_NOWAIT); 1324 1325 backing_object->ref_count -= 2; 1326 } 1327 1328 /* 1329 * vm_object_collapse: 1330 * 1331 * Collapse an object with the object backing it. 1332 * Pages in the backing object are moved into the 1333 * parent, and the backing object is deallocated. 1334 */ 1335 void 1336 vm_object_collapse(vm_object_t object) 1337 { 1338 while (TRUE) { 1339 vm_object_t backing_object; 1340 1341 /* 1342 * Verify that the conditions are right for collapse: 1343 * 1344 * The object exists and the backing object exists. 1345 */ 1346 if (object == NULL) 1347 break; 1348 1349 if ((backing_object = object->backing_object) == NULL) 1350 break; 1351 1352 /* 1353 * we check the backing object first, because it is most likely 1354 * not collapsable. 1355 */ 1356 if (backing_object->handle != NULL || 1357 (backing_object->type != OBJT_DEFAULT && 1358 backing_object->type != OBJT_SWAP) || 1359 (backing_object->flags & OBJ_DEAD) || 1360 object->handle != NULL || 1361 (object->type != OBJT_DEFAULT && 1362 object->type != OBJT_SWAP) || 1363 (object->flags & OBJ_DEAD)) { 1364 break; 1365 } 1366 1367 if ( 1368 object->paging_in_progress != 0 || 1369 backing_object->paging_in_progress != 0 1370 ) { 1371 vm_object_qcollapse(object); 1372 break; 1373 } 1374 1375 /* 1376 * We know that we can either collapse the backing object (if 1377 * the parent is the only reference to it) or (perhaps) have 1378 * the parent bypass the object if the parent happens to shadow 1379 * all the resident pages in the entire backing object. 1380 * 1381 * This is ignoring pager-backed pages such as swap pages. 1382 * vm_object_backing_scan fails the shadowing test in this 1383 * case. 1384 */ 1385 1386 if (backing_object->ref_count == 1) { 1387 /* 1388 * If there is exactly one reference to the backing 1389 * object, we can collapse it into the parent. 1390 */ 1391 vm_object_backing_scan(object, OBSC_COLLAPSE_WAIT); 1392 1393 /* 1394 * Move the pager from backing_object to object. 1395 */ 1396 1397 if (backing_object->type == OBJT_SWAP) { 1398 vm_object_pip_add(backing_object, 1); 1399 1400 /* 1401 * scrap the paging_offset junk and do a 1402 * discrete copy. This also removes major 1403 * assumptions about how the swap-pager 1404 * works from where it doesn't belong. The 1405 * new swapper is able to optimize the 1406 * destroy-source case. 1407 */ 1408 1409 vm_object_pip_add(object, 1); 1410 swap_pager_copy( 1411 backing_object, 1412 object, 1413 OFF_TO_IDX(object->backing_object_offset), TRUE); 1414 vm_object_pip_wakeup(object); 1415 1416 vm_object_pip_wakeup(backing_object); 1417 } 1418 /* 1419 * Object now shadows whatever backing_object did. 1420 * Note that the reference to 1421 * backing_object->backing_object moves from within 1422 * backing_object to within object. 1423 */ 1424 1425 LIST_REMOVE(object, shadow_list); 1426 object->backing_object->shadow_count--; 1427 object->backing_object->generation++; 1428 if (backing_object->backing_object) { 1429 LIST_REMOVE(backing_object, shadow_list); 1430 backing_object->backing_object->shadow_count--; 1431 backing_object->backing_object->generation++; 1432 } 1433 object->backing_object = backing_object->backing_object; 1434 if (object->backing_object) { 1435 LIST_INSERT_HEAD( 1436 &object->backing_object->shadow_head, 1437 object, 1438 shadow_list 1439 ); 1440 object->backing_object->shadow_count++; 1441 object->backing_object->generation++; 1442 } 1443 1444 object->backing_object_offset += 1445 backing_object->backing_object_offset; 1446 1447 /* 1448 * Discard backing_object. 1449 * 1450 * Since the backing object has no pages, no pager left, 1451 * and no object references within it, all that is 1452 * necessary is to dispose of it. 1453 */ 1454 1455 KASSERT(backing_object->ref_count == 1, ("backing_object %p was somehow re-referenced during collapse!", backing_object)); 1456 KASSERT(RB_EMPTY(&backing_object->rb_memq), ("backing_object %p somehow has left over pages during collapse!", backing_object)); 1457 crit_enter(); 1458 TAILQ_REMOVE( 1459 &vm_object_list, 1460 backing_object, 1461 object_list 1462 ); 1463 vm_object_count--; 1464 crit_exit(); 1465 1466 zfree(obj_zone, backing_object); 1467 1468 object_collapses++; 1469 } else { 1470 vm_object_t new_backing_object; 1471 1472 /* 1473 * If we do not entirely shadow the backing object, 1474 * there is nothing we can do so we give up. 1475 */ 1476 1477 if (vm_object_backing_scan(object, OBSC_TEST_ALL_SHADOWED) == 0) { 1478 break; 1479 } 1480 1481 /* 1482 * Make the parent shadow the next object in the 1483 * chain. Deallocating backing_object will not remove 1484 * it, since its reference count is at least 2. 1485 */ 1486 1487 LIST_REMOVE(object, shadow_list); 1488 backing_object->shadow_count--; 1489 backing_object->generation++; 1490 1491 new_backing_object = backing_object->backing_object; 1492 if ((object->backing_object = new_backing_object) != NULL) { 1493 vm_object_reference(new_backing_object); 1494 LIST_INSERT_HEAD( 1495 &new_backing_object->shadow_head, 1496 object, 1497 shadow_list 1498 ); 1499 new_backing_object->shadow_count++; 1500 new_backing_object->generation++; 1501 object->backing_object_offset += 1502 backing_object->backing_object_offset; 1503 } 1504 1505 /* 1506 * Drop the reference count on backing_object. Since 1507 * its ref_count was at least 2, it will not vanish; 1508 * so we don't need to call vm_object_deallocate, but 1509 * we do anyway. 1510 */ 1511 vm_object_deallocate(backing_object); 1512 object_bypasses++; 1513 } 1514 1515 /* 1516 * Try again with this object's new backing object. 1517 */ 1518 } 1519 } 1520 1521 /* 1522 * vm_object_page_remove: [internal] 1523 * 1524 * Removes all physical pages in the specified 1525 * object range from the object's list of pages. 1526 */ 1527 static int vm_object_page_remove_callback(vm_page_t p, void *data); 1528 1529 void 1530 vm_object_page_remove(vm_object_t object, vm_pindex_t start, vm_pindex_t end, 1531 boolean_t clean_only) 1532 { 1533 struct rb_vm_page_scan_info info; 1534 int all; 1535 1536 /* 1537 * Degenerate cases and assertions 1538 */ 1539 if (object == NULL || object->resident_page_count == 0) 1540 return; 1541 KASSERT(object->type != OBJT_PHYS, 1542 ("attempt to remove pages from a physical object")); 1543 1544 /* 1545 * Indicate that paging is occuring on the object 1546 */ 1547 crit_enter(); 1548 vm_object_pip_add(object, 1); 1549 1550 /* 1551 * Figure out the actual removal range and whether we are removing 1552 * the entire contents of the object or not. If removing the entire 1553 * contents, be sure to get all pages, even those that might be 1554 * beyond the end of the object. 1555 */ 1556 info.start_pindex = start; 1557 if (end == 0) 1558 info.end_pindex = (vm_pindex_t)-1; 1559 else 1560 info.end_pindex = end - 1; 1561 info.limit = clean_only; 1562 all = (start == 0 && info.end_pindex >= object->size - 1); 1563 1564 /* 1565 * Loop until we are sure we have gotten them all. 1566 */ 1567 do { 1568 info.error = 0; 1569 vm_page_rb_tree_RB_SCAN(&object->rb_memq, rb_vm_page_scancmp, 1570 vm_object_page_remove_callback, &info); 1571 } while (info.error); 1572 1573 /* 1574 * Cleanup 1575 */ 1576 vm_object_pip_wakeup(object); 1577 crit_exit(); 1578 } 1579 1580 static int 1581 vm_object_page_remove_callback(vm_page_t p, void *data) 1582 { 1583 struct rb_vm_page_scan_info *info = data; 1584 1585 /* 1586 * Wired pages cannot be destroyed, but they can be invalidated 1587 * and we do so if clean_only (limit) is not set. 1588 */ 1589 if (p->wire_count != 0) { 1590 vm_page_protect(p, VM_PROT_NONE); 1591 if (info->limit == 0) 1592 p->valid = 0; 1593 return(0); 1594 } 1595 1596 /* 1597 * The busy flags are only cleared at 1598 * interrupt -- minimize the spl transitions 1599 */ 1600 1601 if (vm_page_sleep_busy(p, TRUE, "vmopar")) { 1602 info->error = 1; 1603 return(0); 1604 } 1605 1606 /* 1607 * limit is our clean_only flag. If set and the page is dirty, do 1608 * not free it. 1609 */ 1610 if (info->limit && p->valid) { 1611 vm_page_test_dirty(p); 1612 if (p->valid & p->dirty) 1613 return(0); 1614 } 1615 1616 /* 1617 * Destroy the page 1618 */ 1619 vm_page_busy(p); 1620 vm_page_protect(p, VM_PROT_NONE); 1621 vm_page_free(p); 1622 return(0); 1623 } 1624 1625 /* 1626 * Routine: vm_object_coalesce 1627 * Function: Coalesces two objects backing up adjoining 1628 * regions of memory into a single object. 1629 * 1630 * returns TRUE if objects were combined. 1631 * 1632 * NOTE: Only works at the moment if the second object is NULL - 1633 * if it's not, which object do we lock first? 1634 * 1635 * Parameters: 1636 * prev_object First object to coalesce 1637 * prev_offset Offset into prev_object 1638 * next_object Second object into coalesce 1639 * next_offset Offset into next_object 1640 * 1641 * prev_size Size of reference to prev_object 1642 * next_size Size of reference to next_object 1643 * 1644 * Conditions: 1645 * The object must *not* be locked. 1646 */ 1647 boolean_t 1648 vm_object_coalesce(vm_object_t prev_object, vm_pindex_t prev_pindex, 1649 vm_size_t prev_size, vm_size_t next_size) 1650 { 1651 vm_pindex_t next_pindex; 1652 1653 if (prev_object == NULL) { 1654 return (TRUE); 1655 } 1656 1657 if (prev_object->type != OBJT_DEFAULT && 1658 prev_object->type != OBJT_SWAP) { 1659 return (FALSE); 1660 } 1661 1662 /* 1663 * Try to collapse the object first 1664 */ 1665 vm_object_collapse(prev_object); 1666 1667 /* 1668 * Can't coalesce if: . more than one reference . paged out . shadows 1669 * another object . has a copy elsewhere (any of which mean that the 1670 * pages not mapped to prev_entry may be in use anyway) 1671 */ 1672 1673 if (prev_object->backing_object != NULL) { 1674 return (FALSE); 1675 } 1676 1677 prev_size >>= PAGE_SHIFT; 1678 next_size >>= PAGE_SHIFT; 1679 next_pindex = prev_pindex + prev_size; 1680 1681 if ((prev_object->ref_count > 1) && 1682 (prev_object->size != next_pindex)) { 1683 return (FALSE); 1684 } 1685 1686 /* 1687 * Remove any pages that may still be in the object from a previous 1688 * deallocation. 1689 */ 1690 if (next_pindex < prev_object->size) { 1691 vm_object_page_remove(prev_object, 1692 next_pindex, 1693 next_pindex + next_size, FALSE); 1694 if (prev_object->type == OBJT_SWAP) 1695 swap_pager_freespace(prev_object, 1696 next_pindex, next_size); 1697 } 1698 1699 /* 1700 * Extend the object if necessary. 1701 */ 1702 if (next_pindex + next_size > prev_object->size) 1703 prev_object->size = next_pindex + next_size; 1704 1705 return (TRUE); 1706 } 1707 1708 void 1709 vm_object_set_writeable_dirty(vm_object_t object) 1710 { 1711 struct vnode *vp; 1712 1713 vm_object_set_flag(object, OBJ_WRITEABLE|OBJ_MIGHTBEDIRTY); 1714 if (object->type == OBJT_VNODE && 1715 (vp = (struct vnode *)object->handle) != NULL) { 1716 if ((vp->v_flag & VOBJDIRTY) == 0) { 1717 vsetflags(vp, VOBJDIRTY); 1718 } 1719 } 1720 } 1721 1722 1723 1724 #include "opt_ddb.h" 1725 #ifdef DDB 1726 #include <sys/kernel.h> 1727 1728 #include <sys/cons.h> 1729 1730 #include <ddb/ddb.h> 1731 1732 static int _vm_object_in_map (vm_map_t map, vm_object_t object, 1733 vm_map_entry_t entry); 1734 static int vm_object_in_map (vm_object_t object); 1735 1736 static int 1737 _vm_object_in_map(vm_map_t map, vm_object_t object, vm_map_entry_t entry) 1738 { 1739 vm_map_t tmpm; 1740 vm_map_entry_t tmpe; 1741 vm_object_t obj; 1742 int entcount; 1743 1744 if (map == 0) 1745 return 0; 1746 if (entry == 0) { 1747 tmpe = map->header.next; 1748 entcount = map->nentries; 1749 while (entcount-- && (tmpe != &map->header)) { 1750 if( _vm_object_in_map(map, object, tmpe)) { 1751 return 1; 1752 } 1753 tmpe = tmpe->next; 1754 } 1755 return (0); 1756 } 1757 switch(entry->maptype) { 1758 case VM_MAPTYPE_SUBMAP: 1759 tmpm = entry->object.sub_map; 1760 tmpe = tmpm->header.next; 1761 entcount = tmpm->nentries; 1762 while (entcount-- && tmpe != &tmpm->header) { 1763 if( _vm_object_in_map(tmpm, object, tmpe)) { 1764 return 1; 1765 } 1766 tmpe = tmpe->next; 1767 } 1768 break; 1769 case VM_MAPTYPE_NORMAL: 1770 case VM_MAPTYPE_VPAGETABLE: 1771 obj = entry->object.vm_object; 1772 while (obj) { 1773 if (obj == object) 1774 return 1; 1775 obj = obj->backing_object; 1776 } 1777 break; 1778 default: 1779 break; 1780 } 1781 return 0; 1782 } 1783 1784 static int vm_object_in_map_callback(struct proc *p, void *data); 1785 1786 struct vm_object_in_map_info { 1787 vm_object_t object; 1788 int rv; 1789 }; 1790 1791 static int 1792 vm_object_in_map(vm_object_t object) 1793 { 1794 struct vm_object_in_map_info info; 1795 1796 info.rv = 0; 1797 info.object = object; 1798 1799 allproc_scan(vm_object_in_map_callback, &info); 1800 if (info.rv) 1801 return 1; 1802 if( _vm_object_in_map(&kernel_map, object, 0)) 1803 return 1; 1804 if( _vm_object_in_map(&pager_map, object, 0)) 1805 return 1; 1806 if( _vm_object_in_map(&buffer_map, object, 0)) 1807 return 1; 1808 return 0; 1809 } 1810 1811 static int 1812 vm_object_in_map_callback(struct proc *p, void *data) 1813 { 1814 struct vm_object_in_map_info *info = data; 1815 1816 if (p->p_vmspace) { 1817 if (_vm_object_in_map(&p->p_vmspace->vm_map, info->object, 0)) { 1818 info->rv = 1; 1819 return -1; 1820 } 1821 } 1822 return (0); 1823 } 1824 1825 DB_SHOW_COMMAND(vmochk, vm_object_check) 1826 { 1827 vm_object_t object; 1828 1829 /* 1830 * make sure that internal objs are in a map somewhere 1831 * and none have zero ref counts. 1832 */ 1833 for (object = TAILQ_FIRST(&vm_object_list); 1834 object != NULL; 1835 object = TAILQ_NEXT(object, object_list)) { 1836 if (object->handle == NULL && 1837 (object->type == OBJT_DEFAULT || object->type == OBJT_SWAP)) { 1838 if (object->ref_count == 0) { 1839 db_printf("vmochk: internal obj has zero ref count: %ld\n", 1840 (long)object->size); 1841 } 1842 if (!vm_object_in_map(object)) { 1843 db_printf( 1844 "vmochk: internal obj is not in a map: " 1845 "ref: %d, size: %lu: 0x%lx, backing_object: %p\n", 1846 object->ref_count, (u_long)object->size, 1847 (u_long)object->size, 1848 (void *)object->backing_object); 1849 } 1850 } 1851 } 1852 } 1853 1854 /* 1855 * vm_object_print: [ debug ] 1856 */ 1857 DB_SHOW_COMMAND(object, vm_object_print_static) 1858 { 1859 /* XXX convert args. */ 1860 vm_object_t object = (vm_object_t)addr; 1861 boolean_t full = have_addr; 1862 1863 vm_page_t p; 1864 1865 /* XXX count is an (unused) arg. Avoid shadowing it. */ 1866 #define count was_count 1867 1868 int count; 1869 1870 if (object == NULL) 1871 return; 1872 1873 db_iprintf( 1874 "Object %p: type=%d, size=0x%lx, res=%d, ref=%d, flags=0x%x\n", 1875 object, (int)object->type, (u_long)object->size, 1876 object->resident_page_count, object->ref_count, object->flags); 1877 /* 1878 * XXX no %qd in kernel. Truncate object->backing_object_offset. 1879 */ 1880 db_iprintf(" sref=%d, backing_object(%d)=(%p)+0x%lx\n", 1881 object->shadow_count, 1882 object->backing_object ? object->backing_object->ref_count : 0, 1883 object->backing_object, (long)object->backing_object_offset); 1884 1885 if (!full) 1886 return; 1887 1888 db_indent += 2; 1889 count = 0; 1890 RB_FOREACH(p, vm_page_rb_tree, &object->rb_memq) { 1891 if (count == 0) 1892 db_iprintf("memory:="); 1893 else if (count == 6) { 1894 db_printf("\n"); 1895 db_iprintf(" ..."); 1896 count = 0; 1897 } else 1898 db_printf(","); 1899 count++; 1900 1901 db_printf("(off=0x%lx,page=0x%lx)", 1902 (u_long) p->pindex, (u_long) VM_PAGE_TO_PHYS(p)); 1903 } 1904 if (count != 0) 1905 db_printf("\n"); 1906 db_indent -= 2; 1907 } 1908 1909 /* XXX. */ 1910 #undef count 1911 1912 /* XXX need this non-static entry for calling from vm_map_print. */ 1913 void 1914 vm_object_print(/* db_expr_t */ long addr, 1915 boolean_t have_addr, 1916 /* db_expr_t */ long count, 1917 char *modif) 1918 { 1919 vm_object_print_static(addr, have_addr, count, modif); 1920 } 1921 1922 DB_SHOW_COMMAND(vmopag, vm_object_print_pages) 1923 { 1924 vm_object_t object; 1925 int nl = 0; 1926 int c; 1927 for (object = TAILQ_FIRST(&vm_object_list); 1928 object != NULL; 1929 object = TAILQ_NEXT(object, object_list)) { 1930 vm_pindex_t idx, fidx; 1931 vm_pindex_t osize; 1932 vm_paddr_t pa = -1, padiff; 1933 int rcount; 1934 vm_page_t m; 1935 1936 db_printf("new object: %p\n", (void *)object); 1937 if ( nl > 18) { 1938 c = cngetc(); 1939 if (c != ' ') 1940 return; 1941 nl = 0; 1942 } 1943 nl++; 1944 rcount = 0; 1945 fidx = 0; 1946 osize = object->size; 1947 if (osize > 128) 1948 osize = 128; 1949 for (idx = 0; idx < osize; idx++) { 1950 m = vm_page_lookup(object, idx); 1951 if (m == NULL) { 1952 if (rcount) { 1953 db_printf(" index(%ld)run(%d)pa(0x%lx)\n", 1954 (long)fidx, rcount, (long)pa); 1955 if ( nl > 18) { 1956 c = cngetc(); 1957 if (c != ' ') 1958 return; 1959 nl = 0; 1960 } 1961 nl++; 1962 rcount = 0; 1963 } 1964 continue; 1965 } 1966 1967 1968 if (rcount && 1969 (VM_PAGE_TO_PHYS(m) == pa + rcount * PAGE_SIZE)) { 1970 ++rcount; 1971 continue; 1972 } 1973 if (rcount) { 1974 padiff = pa + rcount * PAGE_SIZE - VM_PAGE_TO_PHYS(m); 1975 padiff >>= PAGE_SHIFT; 1976 padiff &= PQ_L2_MASK; 1977 if (padiff == 0) { 1978 pa = VM_PAGE_TO_PHYS(m) - rcount * PAGE_SIZE; 1979 ++rcount; 1980 continue; 1981 } 1982 db_printf(" index(%ld)run(%d)pa(0x%lx)", 1983 (long)fidx, rcount, (long)pa); 1984 db_printf("pd(%ld)\n", (long)padiff); 1985 if ( nl > 18) { 1986 c = cngetc(); 1987 if (c != ' ') 1988 return; 1989 nl = 0; 1990 } 1991 nl++; 1992 } 1993 fidx = idx; 1994 pa = VM_PAGE_TO_PHYS(m); 1995 rcount = 1; 1996 } 1997 if (rcount) { 1998 db_printf(" index(%ld)run(%d)pa(0x%lx)\n", 1999 (long)fidx, rcount, (long)pa); 2000 if ( nl > 18) { 2001 c = cngetc(); 2002 if (c != ' ') 2003 return; 2004 nl = 0; 2005 } 2006 nl++; 2007 } 2008 } 2009 } 2010 #endif /* DDB */ 2011