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 1.33 2008/05/09 07:24:48 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_pindex_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 object->swblock_count = 0; 177 RB_INIT(&object->swblock_root); 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 _vm_object_allocate(OBJT_DEFAULT, OFF_TO_IDX(KvaEnd), 197 &kernel_object); 198 199 obj_zone = &obj_zone_store; 200 zbootinit(obj_zone, "VM OBJECT", sizeof (struct vm_object), 201 vm_objects_init, VM_OBJECTS_INIT); 202 } 203 204 void 205 vm_object_init2(void) 206 { 207 zinitna(obj_zone, NULL, NULL, 0, 0, ZONE_PANICFAIL, 1); 208 } 209 210 /* 211 * vm_object_allocate: 212 * 213 * Returns a new object with the given size. 214 */ 215 216 vm_object_t 217 vm_object_allocate(objtype_t type, vm_pindex_t size) 218 { 219 vm_object_t result; 220 221 result = (vm_object_t) zalloc(obj_zone); 222 223 _vm_object_allocate(type, size, result); 224 225 return (result); 226 } 227 228 229 /* 230 * vm_object_reference: 231 * 232 * Gets another reference to the given object. 233 */ 234 void 235 vm_object_reference(vm_object_t object) 236 { 237 if (object == NULL) 238 return; 239 240 object->ref_count++; 241 if (object->type == OBJT_VNODE) { 242 vref(object->handle); 243 /* XXX what if the vnode is being destroyed? */ 244 } 245 } 246 247 static void 248 vm_object_vndeallocate(vm_object_t object) 249 { 250 struct vnode *vp = (struct vnode *) object->handle; 251 252 KASSERT(object->type == OBJT_VNODE, 253 ("vm_object_vndeallocate: not a vnode object")); 254 KASSERT(vp != NULL, ("vm_object_vndeallocate: missing vp")); 255 #ifdef INVARIANTS 256 if (object->ref_count == 0) { 257 vprint("vm_object_vndeallocate", vp); 258 panic("vm_object_vndeallocate: bad object reference count"); 259 } 260 #endif 261 262 object->ref_count--; 263 if (object->ref_count == 0) 264 vclrflags(vp, VTEXT); 265 vrele(vp); 266 } 267 268 /* 269 * vm_object_deallocate: 270 * 271 * Release a reference to the specified object, 272 * gained either through a vm_object_allocate 273 * or a vm_object_reference call. When all references 274 * are gone, storage associated with this object 275 * may be relinquished. 276 * 277 * No object may be locked. 278 */ 279 void 280 vm_object_deallocate(vm_object_t object) 281 { 282 vm_object_t temp; 283 284 while (object != NULL) { 285 if (object->type == OBJT_VNODE) { 286 vm_object_vndeallocate(object); 287 return; 288 } 289 290 if (object->ref_count == 0) { 291 panic("vm_object_deallocate: object deallocated too many times: %d", object->type); 292 } else if (object->ref_count > 2) { 293 object->ref_count--; 294 return; 295 } 296 297 /* 298 * Here on ref_count of one or two, which are special cases for 299 * objects. 300 */ 301 if ((object->ref_count == 2) && (object->shadow_count == 0)) { 302 vm_object_set_flag(object, OBJ_ONEMAPPING); 303 object->ref_count--; 304 return; 305 } else if ((object->ref_count == 2) && (object->shadow_count == 1)) { 306 object->ref_count--; 307 if ((object->handle == NULL) && 308 (object->type == OBJT_DEFAULT || 309 object->type == OBJT_SWAP)) { 310 vm_object_t robject; 311 312 robject = LIST_FIRST(&object->shadow_head); 313 KASSERT(robject != NULL, 314 ("vm_object_deallocate: ref_count: %d, shadow_count: %d", 315 object->ref_count, 316 object->shadow_count)); 317 if ((robject->handle == NULL) && 318 (robject->type == OBJT_DEFAULT || 319 robject->type == OBJT_SWAP)) { 320 321 robject->ref_count++; 322 323 while ( 324 robject->paging_in_progress || 325 object->paging_in_progress 326 ) { 327 vm_object_pip_sleep(robject, "objde1"); 328 vm_object_pip_sleep(object, "objde2"); 329 } 330 331 if (robject->ref_count == 1) { 332 robject->ref_count--; 333 object = robject; 334 goto doterm; 335 } 336 337 object = robject; 338 vm_object_collapse(object); 339 continue; 340 } 341 } 342 343 return; 344 345 } else { 346 object->ref_count--; 347 if (object->ref_count != 0) 348 return; 349 } 350 351 doterm: 352 353 temp = object->backing_object; 354 if (temp) { 355 LIST_REMOVE(object, shadow_list); 356 temp->shadow_count--; 357 temp->generation++; 358 object->backing_object = NULL; 359 } 360 361 /* 362 * Don't double-terminate, we could be in a termination 363 * recursion due to the terminate having to sync data 364 * to disk. 365 */ 366 if ((object->flags & OBJ_DEAD) == 0) 367 vm_object_terminate(object); 368 object = temp; 369 } 370 } 371 372 /* 373 * vm_object_terminate actually destroys the specified object, freeing 374 * up all previously used resources. 375 * 376 * The object must be locked. 377 * This routine may block. 378 */ 379 static int vm_object_terminate_callback(vm_page_t p, void *data); 380 381 void 382 vm_object_terminate(vm_object_t object) 383 { 384 /* 385 * Make sure no one uses us. 386 */ 387 vm_object_set_flag(object, OBJ_DEAD); 388 389 /* 390 * wait for the pageout daemon to be done with the object 391 */ 392 vm_object_pip_wait(object, "objtrm"); 393 394 KASSERT(!object->paging_in_progress, 395 ("vm_object_terminate: pageout in progress")); 396 397 /* 398 * Clean and free the pages, as appropriate. All references to the 399 * object are gone, so we don't need to lock it. 400 */ 401 if (object->type == OBJT_VNODE) { 402 struct vnode *vp; 403 404 /* 405 * Clean pages and flush buffers. 406 */ 407 vm_object_page_clean(object, 0, 0, OBJPC_SYNC); 408 409 vp = (struct vnode *) object->handle; 410 vinvalbuf(vp, V_SAVE, 0, 0); 411 } 412 413 /* 414 * Wait for any I/O to complete, after which there had better not 415 * be any references left on the object. 416 */ 417 vm_object_pip_wait(object, "objtrm"); 418 419 if (object->ref_count != 0) 420 panic("vm_object_terminate: object with references, ref_count=%d", object->ref_count); 421 422 /* 423 * Now free any remaining pages. For internal objects, this also 424 * removes them from paging queues. Don't free wired pages, just 425 * remove them from the object. 426 */ 427 crit_enter(); 428 vm_page_rb_tree_RB_SCAN(&object->rb_memq, NULL, 429 vm_object_terminate_callback, NULL); 430 crit_exit(); 431 432 /* 433 * Let the pager know object is dead. 434 */ 435 vm_pager_deallocate(object); 436 437 /* 438 * Remove the object from the global object list. 439 */ 440 crit_enter(); 441 TAILQ_REMOVE(&vm_object_list, object, object_list); 442 vm_object_count--; 443 crit_exit(); 444 445 vm_object_dead_wakeup(object); 446 if (object->ref_count != 0) 447 panic("vm_object_terminate2: object with references, ref_count=%d", object->ref_count); 448 449 /* 450 * Free the space for the object. 451 */ 452 zfree(obj_zone, object); 453 } 454 455 static int 456 vm_object_terminate_callback(vm_page_t p, void *data __unused) 457 { 458 if (p->busy || (p->flags & PG_BUSY)) 459 panic("vm_object_terminate: freeing busy page %p", p); 460 if (p->wire_count == 0) { 461 vm_page_busy(p); 462 vm_page_free(p); 463 mycpu->gd_cnt.v_pfree++; 464 } else { 465 if (p->queue != PQ_NONE) 466 kprintf("vm_object_terminate: Warning: Encountered wired page %p on queue %d\n", p, p->queue); 467 vm_page_busy(p); 468 vm_page_remove(p); 469 vm_page_wakeup(p); 470 } 471 return(0); 472 } 473 474 /* 475 * The object is dead but still has an object<->pager association. Sleep 476 * and return. The caller typically retests the association in a loop. 477 */ 478 void 479 vm_object_dead_sleep(vm_object_t object, const char *wmesg) 480 { 481 crit_enter(); 482 if (object->handle) { 483 vm_object_set_flag(object, OBJ_DEADWNT); 484 tsleep(object, 0, wmesg, 0); 485 } 486 crit_exit(); 487 } 488 489 /* 490 * Wakeup anyone waiting for the object<->pager disassociation on 491 * a dead object. 492 */ 493 void 494 vm_object_dead_wakeup(vm_object_t object) 495 { 496 if (object->flags & OBJ_DEADWNT) { 497 vm_object_clear_flag(object, OBJ_DEADWNT); 498 wakeup(object); 499 } 500 } 501 502 /* 503 * vm_object_page_clean 504 * 505 * Clean all dirty pages in the specified range of object. Leaves page 506 * on whatever queue it is currently on. If NOSYNC is set then do not 507 * write out pages with PG_NOSYNC set (originally comes from MAP_NOSYNC), 508 * leaving the object dirty. 509 * 510 * When stuffing pages asynchronously, allow clustering. XXX we need a 511 * synchronous clustering mode implementation. 512 * 513 * Odd semantics: if start == end, we clean everything. 514 */ 515 static int vm_object_page_clean_pass1(struct vm_page *p, void *data); 516 static int vm_object_page_clean_pass2(struct vm_page *p, void *data); 517 518 void 519 vm_object_page_clean(vm_object_t object, vm_pindex_t start, vm_pindex_t end, 520 int flags) 521 { 522 struct rb_vm_page_scan_info info; 523 struct vnode *vp; 524 int wholescan; 525 int pagerflags; 526 int curgeneration; 527 528 if (object->type != OBJT_VNODE || 529 (object->flags & OBJ_MIGHTBEDIRTY) == 0) 530 return; 531 532 pagerflags = (flags & (OBJPC_SYNC | OBJPC_INVAL)) ? 533 VM_PAGER_PUT_SYNC : VM_PAGER_CLUSTER_OK; 534 pagerflags |= (flags & OBJPC_INVAL) ? VM_PAGER_PUT_INVAL : 0; 535 536 vp = object->handle; 537 538 /* 539 * Interlock other major object operations. This allows us to 540 * temporarily clear OBJ_WRITEABLE and OBJ_MIGHTBEDIRTY. 541 */ 542 crit_enter(); 543 vm_object_set_flag(object, OBJ_CLEANING); 544 545 /* 546 * Handle 'entire object' case 547 */ 548 info.start_pindex = start; 549 if (end == 0) { 550 info.end_pindex = object->size - 1; 551 } else { 552 info.end_pindex = end - 1; 553 } 554 wholescan = (start == 0 && info.end_pindex == object->size - 1); 555 info.limit = flags; 556 info.pagerflags = pagerflags; 557 info.object = object; 558 559 /* 560 * If cleaning the entire object do a pass to mark the pages read-only. 561 * If everything worked out ok, clear OBJ_WRITEABLE and 562 * OBJ_MIGHTBEDIRTY. 563 */ 564 if (wholescan) { 565 info.error = 0; 566 vm_page_rb_tree_RB_SCAN(&object->rb_memq, rb_vm_page_scancmp, 567 vm_object_page_clean_pass1, &info); 568 if (info.error == 0) { 569 vm_object_clear_flag(object, 570 OBJ_WRITEABLE|OBJ_MIGHTBEDIRTY); 571 if (object->type == OBJT_VNODE && 572 (vp = (struct vnode *)object->handle) != NULL) { 573 if (vp->v_flag & VOBJDIRTY) 574 vclrflags(vp, VOBJDIRTY); 575 } 576 } 577 } 578 579 /* 580 * Do a pass to clean all the dirty pages we find. 581 */ 582 do { 583 info.error = 0; 584 curgeneration = object->generation; 585 vm_page_rb_tree_RB_SCAN(&object->rb_memq, rb_vm_page_scancmp, 586 vm_object_page_clean_pass2, &info); 587 } while (info.error || curgeneration != object->generation); 588 589 vm_object_clear_flag(object, OBJ_CLEANING); 590 crit_exit(); 591 } 592 593 static 594 int 595 vm_object_page_clean_pass1(struct vm_page *p, void *data) 596 { 597 struct rb_vm_page_scan_info *info = data; 598 599 vm_page_flag_set(p, PG_CLEANCHK); 600 if ((info->limit & OBJPC_NOSYNC) && (p->flags & PG_NOSYNC)) 601 info->error = 1; 602 else 603 vm_page_protect(p, VM_PROT_READ); /* must not block */ 604 return(0); 605 } 606 607 static 608 int 609 vm_object_page_clean_pass2(struct vm_page *p, void *data) 610 { 611 struct rb_vm_page_scan_info *info = data; 612 int n; 613 614 /* 615 * Do not mess with pages that were inserted after we started 616 * the cleaning pass. 617 */ 618 if ((p->flags & PG_CLEANCHK) == 0) 619 return(0); 620 621 /* 622 * Before wasting time traversing the pmaps, check for trivial 623 * cases where the page cannot be dirty. 624 */ 625 if (p->valid == 0 || (p->queue - p->pc) == PQ_CACHE) { 626 KKASSERT((p->dirty & p->valid) == 0); 627 return(0); 628 } 629 630 /* 631 * Check whether the page is dirty or not. The page has been set 632 * to be read-only so the check will not race a user dirtying the 633 * page. 634 */ 635 vm_page_test_dirty(p); 636 if ((p->dirty & p->valid) == 0) { 637 vm_page_flag_clear(p, PG_CLEANCHK); 638 return(0); 639 } 640 641 /* 642 * If we have been asked to skip nosync pages and this is a 643 * nosync page, skip it. Note that the object flags were 644 * not cleared in this case (because pass1 will have returned an 645 * error), so we do not have to set them. 646 */ 647 if ((info->limit & OBJPC_NOSYNC) && (p->flags & PG_NOSYNC)) { 648 vm_page_flag_clear(p, PG_CLEANCHK); 649 return(0); 650 } 651 652 /* 653 * Flush as many pages as we can. PG_CLEANCHK will be cleared on 654 * the pages that get successfully flushed. Set info->error if 655 * we raced an object modification. 656 */ 657 n = vm_object_page_collect_flush(info->object, p, info->pagerflags); 658 if (n == 0) 659 info->error = 1; 660 return(0); 661 } 662 663 /* 664 * This routine must be called within a critical section to properly avoid 665 * an interrupt unbusy/free race that can occur prior to the busy check. 666 * 667 * Using the object generation number here to detect page ripout is not 668 * the best idea in the world. XXX 669 * 670 * NOTE: we operate under the assumption that a page found to not be busy 671 * will not be ripped out from under us by an interrupt. XXX we should 672 * recode this to explicitly busy the pages. 673 */ 674 static int 675 vm_object_page_collect_flush(vm_object_t object, vm_page_t p, int pagerflags) 676 { 677 int runlen; 678 int maxf; 679 int chkb; 680 int maxb; 681 int i; 682 int curgeneration; 683 vm_pindex_t pi; 684 vm_page_t maf[vm_pageout_page_count]; 685 vm_page_t mab[vm_pageout_page_count]; 686 vm_page_t ma[vm_pageout_page_count]; 687 688 curgeneration = object->generation; 689 690 pi = p->pindex; 691 while (vm_page_sleep_busy(p, TRUE, "vpcwai")) { 692 if (object->generation != curgeneration) { 693 return(0); 694 } 695 } 696 KKASSERT(p->object == object && p->pindex == pi); 697 698 maxf = 0; 699 for(i = 1; i < vm_pageout_page_count; i++) { 700 vm_page_t tp; 701 702 if ((tp = vm_page_lookup(object, pi + i)) != NULL) { 703 if ((tp->flags & PG_BUSY) || 704 ((pagerflags & VM_PAGER_IGNORE_CLEANCHK) == 0 && 705 (tp->flags & PG_CLEANCHK) == 0) || 706 (tp->busy != 0)) 707 break; 708 if((tp->queue - tp->pc) == PQ_CACHE) { 709 vm_page_flag_clear(tp, PG_CLEANCHK); 710 break; 711 } 712 vm_page_test_dirty(tp); 713 if ((tp->dirty & tp->valid) == 0) { 714 vm_page_flag_clear(tp, PG_CLEANCHK); 715 break; 716 } 717 maf[ i - 1 ] = tp; 718 maxf++; 719 continue; 720 } 721 break; 722 } 723 724 maxb = 0; 725 chkb = vm_pageout_page_count - maxf; 726 if (chkb) { 727 for(i = 1; i < chkb;i++) { 728 vm_page_t tp; 729 730 if ((tp = vm_page_lookup(object, pi - i)) != NULL) { 731 if ((tp->flags & PG_BUSY) || 732 ((pagerflags & VM_PAGER_IGNORE_CLEANCHK) == 0 && 733 (tp->flags & PG_CLEANCHK) == 0) || 734 (tp->busy != 0)) 735 break; 736 if((tp->queue - tp->pc) == PQ_CACHE) { 737 vm_page_flag_clear(tp, PG_CLEANCHK); 738 break; 739 } 740 vm_page_test_dirty(tp); 741 if ((tp->dirty & tp->valid) == 0) { 742 vm_page_flag_clear(tp, PG_CLEANCHK); 743 break; 744 } 745 mab[ i - 1 ] = tp; 746 maxb++; 747 continue; 748 } 749 break; 750 } 751 } 752 753 for(i = 0; i < maxb; i++) { 754 int index = (maxb - i) - 1; 755 ma[index] = mab[i]; 756 vm_page_flag_clear(ma[index], PG_CLEANCHK); 757 } 758 vm_page_flag_clear(p, PG_CLEANCHK); 759 ma[maxb] = p; 760 for(i = 0; i < maxf; i++) { 761 int index = (maxb + i) + 1; 762 ma[index] = maf[i]; 763 vm_page_flag_clear(ma[index], PG_CLEANCHK); 764 } 765 runlen = maxb + maxf + 1; 766 767 vm_pageout_flush(ma, runlen, pagerflags); 768 for (i = 0; i < runlen; i++) { 769 if (ma[i]->valid & ma[i]->dirty) { 770 vm_page_protect(ma[i], VM_PROT_READ); 771 vm_page_flag_set(ma[i], PG_CLEANCHK); 772 773 /* 774 * maxf will end up being the actual number of pages 775 * we wrote out contiguously, non-inclusive of the 776 * first page. We do not count look-behind pages. 777 */ 778 if (i >= maxb + 1 && (maxf > i - maxb - 1)) 779 maxf = i - maxb - 1; 780 } 781 } 782 return(maxf + 1); 783 } 784 785 #ifdef not_used 786 /* XXX I cannot tell if this should be an exported symbol */ 787 /* 788 * vm_object_deactivate_pages 789 * 790 * Deactivate all pages in the specified object. (Keep its pages 791 * in memory even though it is no longer referenced.) 792 * 793 * The object must be locked. 794 */ 795 static int vm_object_deactivate_pages_callback(vm_page_t p, void *data); 796 797 static void 798 vm_object_deactivate_pages(vm_object_t object) 799 { 800 crit_enter(); 801 vm_page_rb_tree_RB_SCAN(&object->rb_memq, NULL, 802 vm_object_deactivate_pages_callback, NULL); 803 crit_exit(); 804 } 805 806 static int 807 vm_object_deactivate_pages_callback(vm_page_t p, void *data __unused) 808 { 809 vm_page_deactivate(p); 810 return(0); 811 } 812 813 #endif 814 815 /* 816 * Same as vm_object_pmap_copy, except range checking really 817 * works, and is meant for small sections of an object. 818 * 819 * This code protects resident pages by making them read-only 820 * and is typically called on a fork or split when a page 821 * is converted to copy-on-write. 822 * 823 * NOTE: If the page is already at VM_PROT_NONE, calling 824 * vm_page_protect will have no effect. 825 */ 826 void 827 vm_object_pmap_copy_1(vm_object_t object, vm_pindex_t start, vm_pindex_t end) 828 { 829 vm_pindex_t idx; 830 vm_page_t p; 831 832 if (object == NULL || (object->flags & OBJ_WRITEABLE) == 0) 833 return; 834 835 /* 836 * spl protection needed to prevent races between the lookup, 837 * an interrupt unbusy/free, and our protect call. 838 */ 839 crit_enter(); 840 for (idx = start; idx < end; idx++) { 841 p = vm_page_lookup(object, idx); 842 if (p == NULL) 843 continue; 844 vm_page_protect(p, VM_PROT_READ); 845 } 846 crit_exit(); 847 } 848 849 /* 850 * vm_object_pmap_remove: 851 * 852 * Removes all physical pages in the specified 853 * object range from all physical maps. 854 * 855 * The object must *not* be locked. 856 */ 857 858 static int vm_object_pmap_remove_callback(vm_page_t p, void *data); 859 860 void 861 vm_object_pmap_remove(vm_object_t object, vm_pindex_t start, vm_pindex_t end) 862 { 863 struct rb_vm_page_scan_info info; 864 865 if (object == NULL) 866 return; 867 info.start_pindex = start; 868 info.end_pindex = end - 1; 869 crit_enter(); 870 vm_page_rb_tree_RB_SCAN(&object->rb_memq, rb_vm_page_scancmp, 871 vm_object_pmap_remove_callback, &info); 872 if (start == 0 && end == object->size) 873 vm_object_clear_flag(object, OBJ_WRITEABLE); 874 crit_exit(); 875 } 876 877 static int 878 vm_object_pmap_remove_callback(vm_page_t p, void *data __unused) 879 { 880 vm_page_protect(p, VM_PROT_NONE); 881 return(0); 882 } 883 884 /* 885 * vm_object_madvise: 886 * 887 * Implements the madvise function at the object/page level. 888 * 889 * MADV_WILLNEED (any object) 890 * 891 * Activate the specified pages if they are resident. 892 * 893 * MADV_DONTNEED (any object) 894 * 895 * Deactivate the specified pages if they are resident. 896 * 897 * MADV_FREE (OBJT_DEFAULT/OBJT_SWAP objects, 898 * OBJ_ONEMAPPING only) 899 * 900 * Deactivate and clean the specified pages if they are 901 * resident. This permits the process to reuse the pages 902 * without faulting or the kernel to reclaim the pages 903 * without I/O. 904 */ 905 void 906 vm_object_madvise(vm_object_t object, vm_pindex_t pindex, int count, int advise) 907 { 908 vm_pindex_t end, tpindex; 909 vm_object_t tobject; 910 vm_page_t m; 911 912 if (object == NULL) 913 return; 914 915 end = pindex + count; 916 917 /* 918 * Locate and adjust resident pages 919 */ 920 921 for (; pindex < end; pindex += 1) { 922 relookup: 923 tobject = object; 924 tpindex = pindex; 925 shadowlookup: 926 /* 927 * MADV_FREE only operates on OBJT_DEFAULT or OBJT_SWAP pages 928 * and those pages must be OBJ_ONEMAPPING. 929 */ 930 if (advise == MADV_FREE) { 931 if ((tobject->type != OBJT_DEFAULT && 932 tobject->type != OBJT_SWAP) || 933 (tobject->flags & OBJ_ONEMAPPING) == 0) { 934 continue; 935 } 936 } 937 938 /* 939 * spl protection is required to avoid a race between the 940 * lookup, an interrupt unbusy/free, and our busy check. 941 */ 942 943 crit_enter(); 944 m = vm_page_lookup(tobject, tpindex); 945 946 if (m == NULL) { 947 /* 948 * There may be swap even if there is no backing page 949 */ 950 if (advise == MADV_FREE && tobject->type == OBJT_SWAP) 951 swap_pager_freespace(tobject, tpindex, 1); 952 953 /* 954 * next object 955 */ 956 crit_exit(); 957 if (tobject->backing_object == NULL) 958 continue; 959 tpindex += OFF_TO_IDX(tobject->backing_object_offset); 960 tobject = tobject->backing_object; 961 goto shadowlookup; 962 } 963 964 /* 965 * If the page is busy or not in a normal active state, 966 * we skip it. If the page is not managed there are no 967 * page queues to mess with. Things can break if we mess 968 * with pages in any of the below states. 969 */ 970 if ( 971 m->hold_count || 972 m->wire_count || 973 (m->flags & PG_UNMANAGED) || 974 m->valid != VM_PAGE_BITS_ALL 975 ) { 976 crit_exit(); 977 continue; 978 } 979 980 if (vm_page_sleep_busy(m, TRUE, "madvpo")) { 981 crit_exit(); 982 goto relookup; 983 } 984 crit_exit(); 985 986 /* 987 * Theoretically once a page is known not to be busy, an 988 * interrupt cannot come along and rip it out from under us. 989 */ 990 991 if (advise == MADV_WILLNEED) { 992 vm_page_activate(m); 993 } else if (advise == MADV_DONTNEED) { 994 vm_page_dontneed(m); 995 } else if (advise == MADV_FREE) { 996 /* 997 * Mark the page clean. This will allow the page 998 * to be freed up by the system. However, such pages 999 * are often reused quickly by malloc()/free() 1000 * so we do not do anything that would cause 1001 * a page fault if we can help it. 1002 * 1003 * Specifically, we do not try to actually free 1004 * the page now nor do we try to put it in the 1005 * cache (which would cause a page fault on reuse). 1006 * 1007 * But we do make the page is freeable as we 1008 * can without actually taking the step of unmapping 1009 * it. 1010 */ 1011 pmap_clear_modify(m); 1012 m->dirty = 0; 1013 m->act_count = 0; 1014 vm_page_dontneed(m); 1015 if (tobject->type == OBJT_SWAP) 1016 swap_pager_freespace(tobject, tpindex, 1); 1017 } 1018 } 1019 } 1020 1021 /* 1022 * vm_object_shadow: 1023 * 1024 * Create a new object which is backed by the 1025 * specified existing object range. The source 1026 * object reference is deallocated. 1027 * 1028 * The new object and offset into that object 1029 * are returned in the source parameters. 1030 */ 1031 1032 void 1033 vm_object_shadow(vm_object_t *object, /* IN/OUT */ 1034 vm_ooffset_t *offset, /* IN/OUT */ 1035 vm_size_t length) 1036 { 1037 vm_object_t source; 1038 vm_object_t result; 1039 1040 source = *object; 1041 1042 /* 1043 * Don't create the new object if the old object isn't shared. 1044 */ 1045 1046 if (source != NULL && 1047 source->ref_count == 1 && 1048 source->handle == NULL && 1049 (source->type == OBJT_DEFAULT || 1050 source->type == OBJT_SWAP)) 1051 return; 1052 1053 /* 1054 * Allocate a new object with the given length 1055 */ 1056 1057 if ((result = vm_object_allocate(OBJT_DEFAULT, length)) == NULL) 1058 panic("vm_object_shadow: no object for shadowing"); 1059 1060 /* 1061 * The new object shadows the source object, adding a reference to it. 1062 * Our caller changes his reference to point to the new object, 1063 * removing a reference to the source object. Net result: no change 1064 * of reference count. 1065 * 1066 * Try to optimize the result object's page color when shadowing 1067 * in order to maintain page coloring consistency in the combined 1068 * shadowed object. 1069 */ 1070 result->backing_object = source; 1071 if (source) { 1072 LIST_INSERT_HEAD(&source->shadow_head, result, shadow_list); 1073 source->shadow_count++; 1074 source->generation++; 1075 result->pg_color = (source->pg_color + OFF_TO_IDX(*offset)) & PQ_L2_MASK; 1076 } 1077 1078 /* 1079 * Store the offset into the source object, and fix up the offset into 1080 * the new object. 1081 */ 1082 1083 result->backing_object_offset = *offset; 1084 1085 /* 1086 * Return the new things 1087 */ 1088 1089 *offset = 0; 1090 *object = result; 1091 } 1092 1093 #define OBSC_TEST_ALL_SHADOWED 0x0001 1094 #define OBSC_COLLAPSE_NOWAIT 0x0002 1095 #define OBSC_COLLAPSE_WAIT 0x0004 1096 1097 static int vm_object_backing_scan_callback(vm_page_t p, void *data); 1098 1099 static __inline int 1100 vm_object_backing_scan(vm_object_t object, int op) 1101 { 1102 struct rb_vm_page_scan_info info; 1103 vm_object_t backing_object; 1104 1105 /* 1106 * spl protection is required to avoid races between the memq/lookup, 1107 * an interrupt doing an unbusy/free, and our busy check. Amoung 1108 * other things. 1109 */ 1110 crit_enter(); 1111 1112 backing_object = object->backing_object; 1113 info.backing_offset_index = OFF_TO_IDX(object->backing_object_offset); 1114 1115 /* 1116 * Initial conditions 1117 */ 1118 1119 if (op & OBSC_TEST_ALL_SHADOWED) { 1120 /* 1121 * We do not want to have to test for the existence of 1122 * swap pages in the backing object. XXX but with the 1123 * new swapper this would be pretty easy to do. 1124 * 1125 * XXX what about anonymous MAP_SHARED memory that hasn't 1126 * been ZFOD faulted yet? If we do not test for this, the 1127 * shadow test may succeed! XXX 1128 */ 1129 if (backing_object->type != OBJT_DEFAULT) { 1130 crit_exit(); 1131 return(0); 1132 } 1133 } 1134 if (op & OBSC_COLLAPSE_WAIT) { 1135 KKASSERT((backing_object->flags & OBJ_DEAD) == 0); 1136 vm_object_set_flag(backing_object, OBJ_DEAD); 1137 } 1138 1139 /* 1140 * Our scan. We have to retry if a negative error code is returned, 1141 * otherwise 0 or 1 will be returned in info.error. 0 Indicates that 1142 * the scan had to be stopped because the parent does not completely 1143 * shadow the child. 1144 */ 1145 info.object = object; 1146 info.backing_object = backing_object; 1147 info.limit = op; 1148 do { 1149 info.error = 1; 1150 vm_page_rb_tree_RB_SCAN(&backing_object->rb_memq, NULL, 1151 vm_object_backing_scan_callback, 1152 &info); 1153 } while (info.error < 0); 1154 crit_exit(); 1155 return(info.error); 1156 } 1157 1158 static int 1159 vm_object_backing_scan_callback(vm_page_t p, void *data) 1160 { 1161 struct rb_vm_page_scan_info *info = data; 1162 vm_object_t backing_object; 1163 vm_object_t object; 1164 vm_pindex_t new_pindex; 1165 vm_pindex_t backing_offset_index; 1166 int op; 1167 1168 new_pindex = p->pindex - info->backing_offset_index; 1169 op = info->limit; 1170 object = info->object; 1171 backing_object = info->backing_object; 1172 backing_offset_index = info->backing_offset_index; 1173 1174 if (op & OBSC_TEST_ALL_SHADOWED) { 1175 vm_page_t pp; 1176 1177 /* 1178 * Ignore pages outside the parent object's range 1179 * and outside the parent object's mapping of the 1180 * backing object. 1181 * 1182 * note that we do not busy the backing object's 1183 * page. 1184 */ 1185 if ( 1186 p->pindex < backing_offset_index || 1187 new_pindex >= object->size 1188 ) { 1189 return(0); 1190 } 1191 1192 /* 1193 * See if the parent has the page or if the parent's 1194 * object pager has the page. If the parent has the 1195 * page but the page is not valid, the parent's 1196 * object pager must have the page. 1197 * 1198 * If this fails, the parent does not completely shadow 1199 * the object and we might as well give up now. 1200 */ 1201 1202 pp = vm_page_lookup(object, new_pindex); 1203 if ((pp == NULL || pp->valid == 0) && 1204 !vm_pager_has_page(object, new_pindex) 1205 ) { 1206 info->error = 0; /* problemo */ 1207 return(-1); /* stop the scan */ 1208 } 1209 } 1210 1211 /* 1212 * Check for busy page 1213 */ 1214 1215 if (op & (OBSC_COLLAPSE_WAIT | OBSC_COLLAPSE_NOWAIT)) { 1216 vm_page_t pp; 1217 1218 if (op & OBSC_COLLAPSE_NOWAIT) { 1219 if ( 1220 (p->flags & PG_BUSY) || 1221 !p->valid || 1222 p->hold_count || 1223 p->wire_count || 1224 p->busy 1225 ) { 1226 return(0); 1227 } 1228 } else if (op & OBSC_COLLAPSE_WAIT) { 1229 if (vm_page_sleep_busy(p, TRUE, "vmocol")) { 1230 /* 1231 * If we slept, anything could have 1232 * happened. Ask that the scan be restarted. 1233 * 1234 * Since the object is marked dead, the 1235 * backing offset should not have changed. 1236 */ 1237 info->error = -1; 1238 return(-1); 1239 } 1240 } 1241 1242 /* 1243 * Busy the page 1244 */ 1245 vm_page_busy(p); 1246 1247 KASSERT( 1248 p->object == backing_object, 1249 ("vm_object_qcollapse(): object mismatch") 1250 ); 1251 1252 /* 1253 * Destroy any associated swap 1254 */ 1255 if (backing_object->type == OBJT_SWAP) 1256 swap_pager_freespace(backing_object, p->pindex, 1); 1257 1258 if ( 1259 p->pindex < backing_offset_index || 1260 new_pindex >= object->size 1261 ) { 1262 /* 1263 * Page is out of the parent object's range, we 1264 * can simply destroy it. 1265 */ 1266 vm_page_protect(p, VM_PROT_NONE); 1267 vm_page_free(p); 1268 return(0); 1269 } 1270 1271 pp = vm_page_lookup(object, new_pindex); 1272 if (pp != NULL || vm_pager_has_page(object, new_pindex)) { 1273 /* 1274 * page already exists in parent OR swap exists 1275 * for this location in the parent. Destroy 1276 * the original page from the backing object. 1277 * 1278 * Leave the parent's page alone 1279 */ 1280 vm_page_protect(p, VM_PROT_NONE); 1281 vm_page_free(p); 1282 return(0); 1283 } 1284 1285 /* 1286 * Page does not exist in parent, rename the 1287 * page from the backing object to the main object. 1288 * 1289 * If the page was mapped to a process, it can remain 1290 * mapped through the rename. 1291 */ 1292 if ((p->queue - p->pc) == PQ_CACHE) 1293 vm_page_deactivate(p); 1294 1295 vm_page_rename(p, object, new_pindex); 1296 /* page automatically made dirty by rename */ 1297 } 1298 return(0); 1299 } 1300 1301 /* 1302 * this version of collapse allows the operation to occur earlier and 1303 * when paging_in_progress is true for an object... This is not a complete 1304 * operation, but should plug 99.9% of the rest of the leaks. 1305 */ 1306 static void 1307 vm_object_qcollapse(vm_object_t object) 1308 { 1309 vm_object_t backing_object = object->backing_object; 1310 1311 if (backing_object->ref_count != 1) 1312 return; 1313 1314 backing_object->ref_count += 2; 1315 1316 vm_object_backing_scan(object, OBSC_COLLAPSE_NOWAIT); 1317 1318 backing_object->ref_count -= 2; 1319 } 1320 1321 /* 1322 * vm_object_collapse: 1323 * 1324 * Collapse an object with the object backing it. 1325 * Pages in the backing object are moved into the 1326 * parent, and the backing object is deallocated. 1327 */ 1328 void 1329 vm_object_collapse(vm_object_t object) 1330 { 1331 while (TRUE) { 1332 vm_object_t backing_object; 1333 1334 /* 1335 * Verify that the conditions are right for collapse: 1336 * 1337 * The object exists and the backing object exists. 1338 */ 1339 if (object == NULL) 1340 break; 1341 1342 if ((backing_object = object->backing_object) == NULL) 1343 break; 1344 1345 /* 1346 * we check the backing object first, because it is most likely 1347 * not collapsable. 1348 */ 1349 if (backing_object->handle != NULL || 1350 (backing_object->type != OBJT_DEFAULT && 1351 backing_object->type != OBJT_SWAP) || 1352 (backing_object->flags & OBJ_DEAD) || 1353 object->handle != NULL || 1354 (object->type != OBJT_DEFAULT && 1355 object->type != OBJT_SWAP) || 1356 (object->flags & OBJ_DEAD)) { 1357 break; 1358 } 1359 1360 if ( 1361 object->paging_in_progress != 0 || 1362 backing_object->paging_in_progress != 0 1363 ) { 1364 vm_object_qcollapse(object); 1365 break; 1366 } 1367 1368 /* 1369 * We know that we can either collapse the backing object (if 1370 * the parent is the only reference to it) or (perhaps) have 1371 * the parent bypass the object if the parent happens to shadow 1372 * all the resident pages in the entire backing object. 1373 * 1374 * This is ignoring pager-backed pages such as swap pages. 1375 * vm_object_backing_scan fails the shadowing test in this 1376 * case. 1377 */ 1378 1379 if (backing_object->ref_count == 1) { 1380 /* 1381 * If there is exactly one reference to the backing 1382 * object, we can collapse it into the parent. 1383 */ 1384 vm_object_backing_scan(object, OBSC_COLLAPSE_WAIT); 1385 1386 /* 1387 * Move the pager from backing_object to object. 1388 */ 1389 1390 if (backing_object->type == OBJT_SWAP) { 1391 vm_object_pip_add(backing_object, 1); 1392 1393 /* 1394 * scrap the paging_offset junk and do a 1395 * discrete copy. This also removes major 1396 * assumptions about how the swap-pager 1397 * works from where it doesn't belong. The 1398 * new swapper is able to optimize the 1399 * destroy-source case. 1400 */ 1401 1402 vm_object_pip_add(object, 1); 1403 swap_pager_copy( 1404 backing_object, 1405 object, 1406 OFF_TO_IDX(object->backing_object_offset), TRUE); 1407 vm_object_pip_wakeup(object); 1408 1409 vm_object_pip_wakeup(backing_object); 1410 } 1411 /* 1412 * Object now shadows whatever backing_object did. 1413 * Note that the reference to 1414 * backing_object->backing_object moves from within 1415 * backing_object to within object. 1416 */ 1417 1418 LIST_REMOVE(object, shadow_list); 1419 object->backing_object->shadow_count--; 1420 object->backing_object->generation++; 1421 if (backing_object->backing_object) { 1422 LIST_REMOVE(backing_object, shadow_list); 1423 backing_object->backing_object->shadow_count--; 1424 backing_object->backing_object->generation++; 1425 } 1426 object->backing_object = backing_object->backing_object; 1427 if (object->backing_object) { 1428 LIST_INSERT_HEAD( 1429 &object->backing_object->shadow_head, 1430 object, 1431 shadow_list 1432 ); 1433 object->backing_object->shadow_count++; 1434 object->backing_object->generation++; 1435 } 1436 1437 object->backing_object_offset += 1438 backing_object->backing_object_offset; 1439 1440 /* 1441 * Discard backing_object. 1442 * 1443 * Since the backing object has no pages, no pager left, 1444 * and no object references within it, all that is 1445 * necessary is to dispose of it. 1446 */ 1447 1448 KASSERT(backing_object->ref_count == 1, ("backing_object %p was somehow re-referenced during collapse!", backing_object)); 1449 KASSERT(RB_EMPTY(&backing_object->rb_memq), ("backing_object %p somehow has left over pages during collapse!", backing_object)); 1450 crit_enter(); 1451 TAILQ_REMOVE( 1452 &vm_object_list, 1453 backing_object, 1454 object_list 1455 ); 1456 vm_object_count--; 1457 crit_exit(); 1458 1459 zfree(obj_zone, backing_object); 1460 1461 object_collapses++; 1462 } else { 1463 vm_object_t new_backing_object; 1464 1465 /* 1466 * If we do not entirely shadow the backing object, 1467 * there is nothing we can do so we give up. 1468 */ 1469 1470 if (vm_object_backing_scan(object, OBSC_TEST_ALL_SHADOWED) == 0) { 1471 break; 1472 } 1473 1474 /* 1475 * Make the parent shadow the next object in the 1476 * chain. Deallocating backing_object will not remove 1477 * it, since its reference count is at least 2. 1478 */ 1479 1480 LIST_REMOVE(object, shadow_list); 1481 backing_object->shadow_count--; 1482 backing_object->generation++; 1483 1484 new_backing_object = backing_object->backing_object; 1485 if ((object->backing_object = new_backing_object) != NULL) { 1486 vm_object_reference(new_backing_object); 1487 LIST_INSERT_HEAD( 1488 &new_backing_object->shadow_head, 1489 object, 1490 shadow_list 1491 ); 1492 new_backing_object->shadow_count++; 1493 new_backing_object->generation++; 1494 object->backing_object_offset += 1495 backing_object->backing_object_offset; 1496 } 1497 1498 /* 1499 * Drop the reference count on backing_object. Since 1500 * its ref_count was at least 2, it will not vanish; 1501 * so we don't need to call vm_object_deallocate, but 1502 * we do anyway. 1503 */ 1504 vm_object_deallocate(backing_object); 1505 object_bypasses++; 1506 } 1507 1508 /* 1509 * Try again with this object's new backing object. 1510 */ 1511 } 1512 } 1513 1514 /* 1515 * vm_object_page_remove: [internal] 1516 * 1517 * Removes all physical pages in the specified 1518 * object range from the object's list of pages. 1519 */ 1520 static int vm_object_page_remove_callback(vm_page_t p, void *data); 1521 1522 void 1523 vm_object_page_remove(vm_object_t object, vm_pindex_t start, vm_pindex_t end, 1524 boolean_t clean_only) 1525 { 1526 struct rb_vm_page_scan_info info; 1527 int all; 1528 1529 /* 1530 * Degenerate cases and assertions 1531 */ 1532 if (object == NULL || 1533 (object->resident_page_count == 0 && object->swblock_count == 0)) { 1534 return; 1535 } 1536 KASSERT(object->type != OBJT_PHYS, 1537 ("attempt to remove pages from a physical object")); 1538 1539 /* 1540 * Indicate that paging is occuring on the object 1541 */ 1542 crit_enter(); 1543 vm_object_pip_add(object, 1); 1544 1545 /* 1546 * Figure out the actual removal range and whether we are removing 1547 * the entire contents of the object or not. If removing the entire 1548 * contents, be sure to get all pages, even those that might be 1549 * beyond the end of the object. 1550 */ 1551 info.start_pindex = start; 1552 if (end == 0) 1553 info.end_pindex = (vm_pindex_t)-1; 1554 else 1555 info.end_pindex = end - 1; 1556 info.limit = clean_only; 1557 all = (start == 0 && info.end_pindex >= object->size - 1); 1558 1559 /* 1560 * Loop until we are sure we have gotten them all. 1561 */ 1562 do { 1563 info.error = 0; 1564 vm_page_rb_tree_RB_SCAN(&object->rb_memq, rb_vm_page_scancmp, 1565 vm_object_page_remove_callback, &info); 1566 } while (info.error); 1567 1568 /* 1569 * Remove any related swap if throwing away pages, or for 1570 * non-swap objects (the swap is a clean copy in that case). 1571 */ 1572 if (object->type != OBJT_SWAP || clean_only == FALSE) { 1573 if (all) 1574 swap_pager_freespace_all(object); 1575 else 1576 swap_pager_freespace(object, info.start_pindex, 1577 info.end_pindex - info.start_pindex + 1); 1578 } 1579 1580 /* 1581 * Cleanup 1582 */ 1583 vm_object_pip_wakeup(object); 1584 crit_exit(); 1585 } 1586 1587 static int 1588 vm_object_page_remove_callback(vm_page_t p, void *data) 1589 { 1590 struct rb_vm_page_scan_info *info = data; 1591 1592 /* 1593 * Wired pages cannot be destroyed, but they can be invalidated 1594 * and we do so if clean_only (limit) is not set. 1595 * 1596 * WARNING! The page may be wired due to being part of a buffer 1597 * cache buffer, and the buffer might be marked B_CACHE. 1598 * This is fine as part of a truncation but VFSs must be 1599 * sure to fix the buffer up when re-extending the file. 1600 */ 1601 if (p->wire_count != 0) { 1602 vm_page_protect(p, VM_PROT_NONE); 1603 if (info->limit == 0) 1604 p->valid = 0; 1605 return(0); 1606 } 1607 1608 /* 1609 * The busy flags are only cleared at 1610 * interrupt -- minimize the spl transitions 1611 */ 1612 1613 if (vm_page_sleep_busy(p, TRUE, "vmopar")) { 1614 info->error = 1; 1615 return(0); 1616 } 1617 1618 /* 1619 * limit is our clean_only flag. If set and the page is dirty, do 1620 * not free it. If set and the page is being held by someone, do 1621 * not free it. 1622 */ 1623 if (info->limit && p->valid) { 1624 vm_page_test_dirty(p); 1625 if (p->valid & p->dirty) 1626 return(0); 1627 if (p->hold_count) 1628 return(0); 1629 } 1630 1631 /* 1632 * Destroy the page 1633 */ 1634 vm_page_busy(p); 1635 vm_page_protect(p, VM_PROT_NONE); 1636 vm_page_free(p); 1637 return(0); 1638 } 1639 1640 /* 1641 * Routine: vm_object_coalesce 1642 * Function: Coalesces two objects backing up adjoining 1643 * regions of memory into a single object. 1644 * 1645 * returns TRUE if objects were combined. 1646 * 1647 * NOTE: Only works at the moment if the second object is NULL - 1648 * if it's not, which object do we lock first? 1649 * 1650 * Parameters: 1651 * prev_object First object to coalesce 1652 * prev_offset Offset into prev_object 1653 * next_object Second object into coalesce 1654 * next_offset Offset into next_object 1655 * 1656 * prev_size Size of reference to prev_object 1657 * next_size Size of reference to next_object 1658 * 1659 * Conditions: 1660 * The object must *not* be locked. 1661 */ 1662 boolean_t 1663 vm_object_coalesce(vm_object_t prev_object, vm_pindex_t prev_pindex, 1664 vm_size_t prev_size, vm_size_t next_size) 1665 { 1666 vm_pindex_t next_pindex; 1667 1668 if (prev_object == NULL) { 1669 return (TRUE); 1670 } 1671 1672 if (prev_object->type != OBJT_DEFAULT && 1673 prev_object->type != OBJT_SWAP) { 1674 return (FALSE); 1675 } 1676 1677 /* 1678 * Try to collapse the object first 1679 */ 1680 vm_object_collapse(prev_object); 1681 1682 /* 1683 * Can't coalesce if: . more than one reference . paged out . shadows 1684 * another object . has a copy elsewhere (any of which mean that the 1685 * pages not mapped to prev_entry may be in use anyway) 1686 */ 1687 1688 if (prev_object->backing_object != NULL) { 1689 return (FALSE); 1690 } 1691 1692 prev_size >>= PAGE_SHIFT; 1693 next_size >>= PAGE_SHIFT; 1694 next_pindex = prev_pindex + prev_size; 1695 1696 if ((prev_object->ref_count > 1) && 1697 (prev_object->size != next_pindex)) { 1698 return (FALSE); 1699 } 1700 1701 /* 1702 * Remove any pages that may still be in the object from a previous 1703 * deallocation. 1704 */ 1705 if (next_pindex < prev_object->size) { 1706 vm_object_page_remove(prev_object, 1707 next_pindex, 1708 next_pindex + next_size, FALSE); 1709 if (prev_object->type == OBJT_SWAP) 1710 swap_pager_freespace(prev_object, 1711 next_pindex, next_size); 1712 } 1713 1714 /* 1715 * Extend the object if necessary. 1716 */ 1717 if (next_pindex + next_size > prev_object->size) 1718 prev_object->size = next_pindex + next_size; 1719 1720 return (TRUE); 1721 } 1722 1723 void 1724 vm_object_set_writeable_dirty(vm_object_t object) 1725 { 1726 struct vnode *vp; 1727 1728 vm_object_set_flag(object, OBJ_WRITEABLE|OBJ_MIGHTBEDIRTY); 1729 if (object->type == OBJT_VNODE && 1730 (vp = (struct vnode *)object->handle) != NULL) { 1731 if ((vp->v_flag & VOBJDIRTY) == 0) { 1732 vsetflags(vp, VOBJDIRTY); 1733 } 1734 } 1735 } 1736 1737 1738 1739 #include "opt_ddb.h" 1740 #ifdef DDB 1741 #include <sys/kernel.h> 1742 1743 #include <sys/cons.h> 1744 1745 #include <ddb/ddb.h> 1746 1747 static int _vm_object_in_map (vm_map_t map, vm_object_t object, 1748 vm_map_entry_t entry); 1749 static int vm_object_in_map (vm_object_t object); 1750 1751 static int 1752 _vm_object_in_map(vm_map_t map, vm_object_t object, vm_map_entry_t entry) 1753 { 1754 vm_map_t tmpm; 1755 vm_map_entry_t tmpe; 1756 vm_object_t obj; 1757 int entcount; 1758 1759 if (map == 0) 1760 return 0; 1761 if (entry == 0) { 1762 tmpe = map->header.next; 1763 entcount = map->nentries; 1764 while (entcount-- && (tmpe != &map->header)) { 1765 if( _vm_object_in_map(map, object, tmpe)) { 1766 return 1; 1767 } 1768 tmpe = tmpe->next; 1769 } 1770 return (0); 1771 } 1772 switch(entry->maptype) { 1773 case VM_MAPTYPE_SUBMAP: 1774 tmpm = entry->object.sub_map; 1775 tmpe = tmpm->header.next; 1776 entcount = tmpm->nentries; 1777 while (entcount-- && tmpe != &tmpm->header) { 1778 if( _vm_object_in_map(tmpm, object, tmpe)) { 1779 return 1; 1780 } 1781 tmpe = tmpe->next; 1782 } 1783 break; 1784 case VM_MAPTYPE_NORMAL: 1785 case VM_MAPTYPE_VPAGETABLE: 1786 obj = entry->object.vm_object; 1787 while (obj) { 1788 if (obj == object) 1789 return 1; 1790 obj = obj->backing_object; 1791 } 1792 break; 1793 default: 1794 break; 1795 } 1796 return 0; 1797 } 1798 1799 static int vm_object_in_map_callback(struct proc *p, void *data); 1800 1801 struct vm_object_in_map_info { 1802 vm_object_t object; 1803 int rv; 1804 }; 1805 1806 static int 1807 vm_object_in_map(vm_object_t object) 1808 { 1809 struct vm_object_in_map_info info; 1810 1811 info.rv = 0; 1812 info.object = object; 1813 1814 allproc_scan(vm_object_in_map_callback, &info); 1815 if (info.rv) 1816 return 1; 1817 if( _vm_object_in_map(&kernel_map, object, 0)) 1818 return 1; 1819 if( _vm_object_in_map(&pager_map, object, 0)) 1820 return 1; 1821 if( _vm_object_in_map(&buffer_map, object, 0)) 1822 return 1; 1823 return 0; 1824 } 1825 1826 static int 1827 vm_object_in_map_callback(struct proc *p, void *data) 1828 { 1829 struct vm_object_in_map_info *info = data; 1830 1831 if (p->p_vmspace) { 1832 if (_vm_object_in_map(&p->p_vmspace->vm_map, info->object, 0)) { 1833 info->rv = 1; 1834 return -1; 1835 } 1836 } 1837 return (0); 1838 } 1839 1840 DB_SHOW_COMMAND(vmochk, vm_object_check) 1841 { 1842 vm_object_t object; 1843 1844 /* 1845 * make sure that internal objs are in a map somewhere 1846 * and none have zero ref counts. 1847 */ 1848 for (object = TAILQ_FIRST(&vm_object_list); 1849 object != NULL; 1850 object = TAILQ_NEXT(object, object_list)) { 1851 if (object->type == OBJT_MARKER) 1852 continue; 1853 if (object->handle == NULL && 1854 (object->type == OBJT_DEFAULT || object->type == OBJT_SWAP)) { 1855 if (object->ref_count == 0) { 1856 db_printf("vmochk: internal obj has zero ref count: %ld\n", 1857 (long)object->size); 1858 } 1859 if (!vm_object_in_map(object)) { 1860 db_printf( 1861 "vmochk: internal obj is not in a map: " 1862 "ref: %d, size: %lu: 0x%lx, backing_object: %p\n", 1863 object->ref_count, (u_long)object->size, 1864 (u_long)object->size, 1865 (void *)object->backing_object); 1866 } 1867 } 1868 } 1869 } 1870 1871 /* 1872 * vm_object_print: [ debug ] 1873 */ 1874 DB_SHOW_COMMAND(object, vm_object_print_static) 1875 { 1876 /* XXX convert args. */ 1877 vm_object_t object = (vm_object_t)addr; 1878 boolean_t full = have_addr; 1879 1880 vm_page_t p; 1881 1882 /* XXX count is an (unused) arg. Avoid shadowing it. */ 1883 #define count was_count 1884 1885 int count; 1886 1887 if (object == NULL) 1888 return; 1889 1890 db_iprintf( 1891 "Object %p: type=%d, size=0x%lx, res=%d, ref=%d, flags=0x%x\n", 1892 object, (int)object->type, (u_long)object->size, 1893 object->resident_page_count, object->ref_count, object->flags); 1894 /* 1895 * XXX no %qd in kernel. Truncate object->backing_object_offset. 1896 */ 1897 db_iprintf(" sref=%d, backing_object(%d)=(%p)+0x%lx\n", 1898 object->shadow_count, 1899 object->backing_object ? object->backing_object->ref_count : 0, 1900 object->backing_object, (long)object->backing_object_offset); 1901 1902 if (!full) 1903 return; 1904 1905 db_indent += 2; 1906 count = 0; 1907 RB_FOREACH(p, vm_page_rb_tree, &object->rb_memq) { 1908 if (count == 0) 1909 db_iprintf("memory:="); 1910 else if (count == 6) { 1911 db_printf("\n"); 1912 db_iprintf(" ..."); 1913 count = 0; 1914 } else 1915 db_printf(","); 1916 count++; 1917 1918 db_printf("(off=0x%lx,page=0x%lx)", 1919 (u_long) p->pindex, (u_long) VM_PAGE_TO_PHYS(p)); 1920 } 1921 if (count != 0) 1922 db_printf("\n"); 1923 db_indent -= 2; 1924 } 1925 1926 /* XXX. */ 1927 #undef count 1928 1929 /* XXX need this non-static entry for calling from vm_map_print. */ 1930 void 1931 vm_object_print(/* db_expr_t */ long addr, 1932 boolean_t have_addr, 1933 /* db_expr_t */ long count, 1934 char *modif) 1935 { 1936 vm_object_print_static(addr, have_addr, count, modif); 1937 } 1938 1939 DB_SHOW_COMMAND(vmopag, vm_object_print_pages) 1940 { 1941 vm_object_t object; 1942 int nl = 0; 1943 int c; 1944 for (object = TAILQ_FIRST(&vm_object_list); 1945 object != NULL; 1946 object = TAILQ_NEXT(object, object_list)) { 1947 vm_pindex_t idx, fidx; 1948 vm_pindex_t osize; 1949 vm_paddr_t pa = -1, padiff; 1950 int rcount; 1951 vm_page_t m; 1952 1953 if (object->type == OBJT_MARKER) 1954 continue; 1955 db_printf("new object: %p\n", (void *)object); 1956 if ( nl > 18) { 1957 c = cngetc(); 1958 if (c != ' ') 1959 return; 1960 nl = 0; 1961 } 1962 nl++; 1963 rcount = 0; 1964 fidx = 0; 1965 osize = object->size; 1966 if (osize > 128) 1967 osize = 128; 1968 for (idx = 0; idx < osize; idx++) { 1969 m = vm_page_lookup(object, idx); 1970 if (m == NULL) { 1971 if (rcount) { 1972 db_printf(" index(%ld)run(%d)pa(0x%lx)\n", 1973 (long)fidx, rcount, (long)pa); 1974 if ( nl > 18) { 1975 c = cngetc(); 1976 if (c != ' ') 1977 return; 1978 nl = 0; 1979 } 1980 nl++; 1981 rcount = 0; 1982 } 1983 continue; 1984 } 1985 1986 1987 if (rcount && 1988 (VM_PAGE_TO_PHYS(m) == pa + rcount * PAGE_SIZE)) { 1989 ++rcount; 1990 continue; 1991 } 1992 if (rcount) { 1993 padiff = pa + rcount * PAGE_SIZE - VM_PAGE_TO_PHYS(m); 1994 padiff >>= PAGE_SHIFT; 1995 padiff &= PQ_L2_MASK; 1996 if (padiff == 0) { 1997 pa = VM_PAGE_TO_PHYS(m) - rcount * PAGE_SIZE; 1998 ++rcount; 1999 continue; 2000 } 2001 db_printf(" index(%ld)run(%d)pa(0x%lx)", 2002 (long)fidx, rcount, (long)pa); 2003 db_printf("pd(%ld)\n", (long)padiff); 2004 if ( nl > 18) { 2005 c = cngetc(); 2006 if (c != ' ') 2007 return; 2008 nl = 0; 2009 } 2010 nl++; 2011 } 2012 fidx = idx; 2013 pa = VM_PAGE_TO_PHYS(m); 2014 rcount = 1; 2015 } 2016 if (rcount) { 2017 db_printf(" index(%ld)run(%d)pa(0x%lx)\n", 2018 (long)fidx, rcount, (long)pa); 2019 if ( nl > 18) { 2020 c = cngetc(); 2021 if (c != ' ') 2022 return; 2023 nl = 0; 2024 } 2025 nl++; 2026 } 2027 } 2028 } 2029 #endif /* DDB */ 2030