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 1.29 2006/12/28 21:24:02 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 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 vm_page_busy(p); 464 vm_page_remove(p); 465 vm_page_wakeup(p); 466 } 467 return(0); 468 } 469 470 /* 471 * vm_object_page_clean 472 * 473 * Clean all dirty pages in the specified range of object. Leaves page 474 * on whatever queue it is currently on. If NOSYNC is set then do not 475 * write out pages with PG_NOSYNC set (originally comes from MAP_NOSYNC), 476 * leaving the object dirty. 477 * 478 * When stuffing pages asynchronously, allow clustering. XXX we need a 479 * synchronous clustering mode implementation. 480 * 481 * Odd semantics: if start == end, we clean everything. 482 */ 483 static int vm_object_page_clean_pass1(struct vm_page *p, void *data); 484 static int vm_object_page_clean_pass2(struct vm_page *p, void *data); 485 486 void 487 vm_object_page_clean(vm_object_t object, vm_pindex_t start, vm_pindex_t end, 488 int flags) 489 { 490 struct rb_vm_page_scan_info info; 491 struct vnode *vp; 492 int wholescan; 493 int pagerflags; 494 int curgeneration; 495 496 if (object->type != OBJT_VNODE || 497 (object->flags & OBJ_MIGHTBEDIRTY) == 0) 498 return; 499 500 pagerflags = (flags & (OBJPC_SYNC | OBJPC_INVAL)) ? 501 VM_PAGER_PUT_SYNC : VM_PAGER_CLUSTER_OK; 502 pagerflags |= (flags & OBJPC_INVAL) ? VM_PAGER_PUT_INVAL : 0; 503 504 vp = object->handle; 505 506 /* 507 * Interlock other major object operations. This allows us to 508 * temporarily clear OBJ_WRITEABLE and OBJ_MIGHTBEDIRTY. 509 */ 510 crit_enter(); 511 vm_object_set_flag(object, OBJ_CLEANING); 512 513 /* 514 * Handle 'entire object' case 515 */ 516 info.start_pindex = start; 517 if (end == 0) { 518 info.end_pindex = object->size - 1; 519 } else { 520 info.end_pindex = end - 1; 521 } 522 wholescan = (start == 0 && info.end_pindex == object->size - 1); 523 info.limit = flags; 524 info.pagerflags = pagerflags; 525 info.object = object; 526 527 /* 528 * If cleaning the entire object do a pass to mark the pages read-only. 529 * If everything worked out ok, clear OBJ_WRITEABLE and 530 * OBJ_MIGHTBEDIRTY. 531 */ 532 if (wholescan) { 533 info.error = 0; 534 vm_page_rb_tree_RB_SCAN(&object->rb_memq, rb_vm_page_scancmp, 535 vm_object_page_clean_pass1, &info); 536 if (info.error == 0) { 537 vm_object_clear_flag(object, 538 OBJ_WRITEABLE|OBJ_MIGHTBEDIRTY); 539 if (object->type == OBJT_VNODE && 540 (vp = (struct vnode *)object->handle) != NULL) { 541 if (vp->v_flag & VOBJDIRTY) 542 vclrflags(vp, VOBJDIRTY); 543 } 544 } 545 } 546 547 /* 548 * Do a pass to clean all the dirty pages we find. 549 */ 550 do { 551 info.error = 0; 552 curgeneration = object->generation; 553 vm_page_rb_tree_RB_SCAN(&object->rb_memq, rb_vm_page_scancmp, 554 vm_object_page_clean_pass2, &info); 555 } while (info.error || curgeneration != object->generation); 556 557 vm_object_clear_flag(object, OBJ_CLEANING); 558 crit_exit(); 559 } 560 561 static 562 int 563 vm_object_page_clean_pass1(struct vm_page *p, void *data) 564 { 565 struct rb_vm_page_scan_info *info = data; 566 567 vm_page_flag_set(p, PG_CLEANCHK); 568 if ((info->limit & OBJPC_NOSYNC) && (p->flags & PG_NOSYNC)) 569 info->error = 1; 570 else 571 vm_page_protect(p, VM_PROT_READ); 572 return(0); 573 } 574 575 static 576 int 577 vm_object_page_clean_pass2(struct vm_page *p, void *data) 578 { 579 struct rb_vm_page_scan_info *info = data; 580 int n; 581 582 /* 583 * Do not mess with pages that were inserted after we started 584 * the cleaning pass. 585 */ 586 if ((p->flags & PG_CLEANCHK) == 0) 587 return(0); 588 589 /* 590 * Before wasting time traversing the pmaps, check for trivial 591 * cases where the page cannot be dirty. 592 */ 593 if (p->valid == 0 || (p->queue - p->pc) == PQ_CACHE) { 594 KKASSERT((p->dirty & p->valid) == 0); 595 return(0); 596 } 597 598 /* 599 * Check whether the page is dirty or not. The page has been set 600 * to be read-only so the check will not race a user dirtying the 601 * page. 602 */ 603 vm_page_test_dirty(p); 604 if ((p->dirty & p->valid) == 0) { 605 vm_page_flag_clear(p, PG_CLEANCHK); 606 return(0); 607 } 608 609 /* 610 * If we have been asked to skip nosync pages and this is a 611 * nosync page, skip it. Note that the object flags were 612 * not cleared in this case (because pass1 will have returned an 613 * error), so we do not have to set them. 614 */ 615 if ((info->limit & OBJPC_NOSYNC) && (p->flags & PG_NOSYNC)) { 616 vm_page_flag_clear(p, PG_CLEANCHK); 617 return(0); 618 } 619 620 /* 621 * Flush as many pages as we can. PG_CLEANCHK will be cleared on 622 * the pages that get successfully flushed. Set info->error if 623 * we raced an object modification. 624 */ 625 n = vm_object_page_collect_flush(info->object, p, info->pagerflags); 626 if (n == 0) 627 info->error = 1; 628 return(0); 629 } 630 631 /* 632 * This routine must be called within a critical section to properly avoid 633 * an interrupt unbusy/free race that can occur prior to the busy check. 634 * 635 * Using the object generation number here to detect page ripout is not 636 * the best idea in the world. XXX 637 * 638 * NOTE: we operate under the assumption that a page found to not be busy 639 * will not be ripped out from under us by an interrupt. XXX we should 640 * recode this to explicitly busy the pages. 641 */ 642 static int 643 vm_object_page_collect_flush(vm_object_t object, vm_page_t p, int pagerflags) 644 { 645 int runlen; 646 int maxf; 647 int chkb; 648 int maxb; 649 int i; 650 int curgeneration; 651 vm_pindex_t pi; 652 vm_page_t maf[vm_pageout_page_count]; 653 vm_page_t mab[vm_pageout_page_count]; 654 vm_page_t ma[vm_pageout_page_count]; 655 656 curgeneration = object->generation; 657 658 pi = p->pindex; 659 while (vm_page_sleep_busy(p, TRUE, "vpcwai")) { 660 if (object->generation != curgeneration) { 661 return(0); 662 } 663 } 664 KKASSERT(p->object == object && p->pindex == pi); 665 666 maxf = 0; 667 for(i = 1; i < vm_pageout_page_count; i++) { 668 vm_page_t tp; 669 670 if ((tp = vm_page_lookup(object, pi + i)) != NULL) { 671 if ((tp->flags & PG_BUSY) || 672 ((pagerflags & VM_PAGER_IGNORE_CLEANCHK) == 0 && 673 (tp->flags & PG_CLEANCHK) == 0) || 674 (tp->busy != 0)) 675 break; 676 if((tp->queue - tp->pc) == PQ_CACHE) { 677 vm_page_flag_clear(tp, PG_CLEANCHK); 678 break; 679 } 680 vm_page_test_dirty(tp); 681 if ((tp->dirty & tp->valid) == 0) { 682 vm_page_flag_clear(tp, PG_CLEANCHK); 683 break; 684 } 685 maf[ i - 1 ] = tp; 686 maxf++; 687 continue; 688 } 689 break; 690 } 691 692 maxb = 0; 693 chkb = vm_pageout_page_count - maxf; 694 if (chkb) { 695 for(i = 1; i < chkb;i++) { 696 vm_page_t tp; 697 698 if ((tp = vm_page_lookup(object, pi - i)) != NULL) { 699 if ((tp->flags & PG_BUSY) || 700 ((pagerflags & VM_PAGER_IGNORE_CLEANCHK) == 0 && 701 (tp->flags & PG_CLEANCHK) == 0) || 702 (tp->busy != 0)) 703 break; 704 if((tp->queue - tp->pc) == PQ_CACHE) { 705 vm_page_flag_clear(tp, PG_CLEANCHK); 706 break; 707 } 708 vm_page_test_dirty(tp); 709 if ((tp->dirty & tp->valid) == 0) { 710 vm_page_flag_clear(tp, PG_CLEANCHK); 711 break; 712 } 713 mab[ i - 1 ] = tp; 714 maxb++; 715 continue; 716 } 717 break; 718 } 719 } 720 721 for(i = 0; i < maxb; i++) { 722 int index = (maxb - i) - 1; 723 ma[index] = mab[i]; 724 vm_page_flag_clear(ma[index], PG_CLEANCHK); 725 } 726 vm_page_flag_clear(p, PG_CLEANCHK); 727 ma[maxb] = p; 728 for(i = 0; i < maxf; i++) { 729 int index = (maxb + i) + 1; 730 ma[index] = maf[i]; 731 vm_page_flag_clear(ma[index], PG_CLEANCHK); 732 } 733 runlen = maxb + maxf + 1; 734 735 vm_pageout_flush(ma, runlen, pagerflags); 736 for (i = 0; i < runlen; i++) { 737 if (ma[i]->valid & ma[i]->dirty) { 738 vm_page_protect(ma[i], VM_PROT_READ); 739 vm_page_flag_set(ma[i], PG_CLEANCHK); 740 741 /* 742 * maxf will end up being the actual number of pages 743 * we wrote out contiguously, non-inclusive of the 744 * first page. We do not count look-behind pages. 745 */ 746 if (i >= maxb + 1 && (maxf > i - maxb - 1)) 747 maxf = i - maxb - 1; 748 } 749 } 750 return(maxf + 1); 751 } 752 753 #ifdef not_used 754 /* XXX I cannot tell if this should be an exported symbol */ 755 /* 756 * vm_object_deactivate_pages 757 * 758 * Deactivate all pages in the specified object. (Keep its pages 759 * in memory even though it is no longer referenced.) 760 * 761 * The object must be locked. 762 */ 763 static int vm_object_deactivate_pages_callback(vm_page_t p, void *data); 764 765 static void 766 vm_object_deactivate_pages(vm_object_t object) 767 { 768 crit_enter(); 769 vm_page_rb_tree_RB_SCAN(&object->rb_memq, NULL, 770 vm_object_deactivate_pages_callback, NULL); 771 crit_exit(); 772 } 773 774 static int 775 vm_object_deactivate_pages_callback(vm_page_t p, void *data __unused) 776 { 777 vm_page_deactivate(p); 778 return(0); 779 } 780 781 #endif 782 783 /* 784 * Same as vm_object_pmap_copy, except range checking really 785 * works, and is meant for small sections of an object. 786 * 787 * This code protects resident pages by making them read-only 788 * and is typically called on a fork or split when a page 789 * is converted to copy-on-write. 790 * 791 * NOTE: If the page is already at VM_PROT_NONE, calling 792 * vm_page_protect will have no effect. 793 */ 794 void 795 vm_object_pmap_copy_1(vm_object_t object, vm_pindex_t start, vm_pindex_t end) 796 { 797 vm_pindex_t idx; 798 vm_page_t p; 799 800 if (object == NULL || (object->flags & OBJ_WRITEABLE) == 0) 801 return; 802 803 /* 804 * spl protection needed to prevent races between the lookup, 805 * an interrupt unbusy/free, and our protect call. 806 */ 807 crit_enter(); 808 for (idx = start; idx < end; idx++) { 809 p = vm_page_lookup(object, idx); 810 if (p == NULL) 811 continue; 812 vm_page_protect(p, VM_PROT_READ); 813 } 814 crit_exit(); 815 } 816 817 /* 818 * vm_object_pmap_remove: 819 * 820 * Removes all physical pages in the specified 821 * object range from all physical maps. 822 * 823 * The object must *not* be locked. 824 */ 825 826 static int vm_object_pmap_remove_callback(vm_page_t p, void *data); 827 828 void 829 vm_object_pmap_remove(vm_object_t object, vm_pindex_t start, vm_pindex_t end) 830 { 831 struct rb_vm_page_scan_info info; 832 833 if (object == NULL) 834 return; 835 info.start_pindex = start; 836 info.end_pindex = end - 1; 837 crit_enter(); 838 vm_page_rb_tree_RB_SCAN(&object->rb_memq, rb_vm_page_scancmp, 839 vm_object_pmap_remove_callback, &info); 840 if (start == 0 && end == object->size) 841 vm_object_clear_flag(object, OBJ_WRITEABLE); 842 crit_exit(); 843 } 844 845 static int 846 vm_object_pmap_remove_callback(vm_page_t p, void *data __unused) 847 { 848 vm_page_protect(p, VM_PROT_NONE); 849 return(0); 850 } 851 852 /* 853 * vm_object_madvise: 854 * 855 * Implements the madvise function at the object/page level. 856 * 857 * MADV_WILLNEED (any object) 858 * 859 * Activate the specified pages if they are resident. 860 * 861 * MADV_DONTNEED (any object) 862 * 863 * Deactivate the specified pages if they are resident. 864 * 865 * MADV_FREE (OBJT_DEFAULT/OBJT_SWAP objects, 866 * OBJ_ONEMAPPING only) 867 * 868 * Deactivate and clean the specified pages if they are 869 * resident. This permits the process to reuse the pages 870 * without faulting or the kernel to reclaim the pages 871 * without I/O. 872 */ 873 void 874 vm_object_madvise(vm_object_t object, vm_pindex_t pindex, int count, int advise) 875 { 876 vm_pindex_t end, tpindex; 877 vm_object_t tobject; 878 vm_page_t m; 879 880 if (object == NULL) 881 return; 882 883 end = pindex + count; 884 885 /* 886 * Locate and adjust resident pages 887 */ 888 889 for (; pindex < end; pindex += 1) { 890 relookup: 891 tobject = object; 892 tpindex = pindex; 893 shadowlookup: 894 /* 895 * MADV_FREE only operates on OBJT_DEFAULT or OBJT_SWAP pages 896 * and those pages must be OBJ_ONEMAPPING. 897 */ 898 if (advise == MADV_FREE) { 899 if ((tobject->type != OBJT_DEFAULT && 900 tobject->type != OBJT_SWAP) || 901 (tobject->flags & OBJ_ONEMAPPING) == 0) { 902 continue; 903 } 904 } 905 906 /* 907 * spl protection is required to avoid a race between the 908 * lookup, an interrupt unbusy/free, and our busy check. 909 */ 910 911 crit_enter(); 912 m = vm_page_lookup(tobject, tpindex); 913 914 if (m == NULL) { 915 /* 916 * There may be swap even if there is no backing page 917 */ 918 if (advise == MADV_FREE && tobject->type == OBJT_SWAP) 919 swap_pager_freespace(tobject, tpindex, 1); 920 921 /* 922 * next object 923 */ 924 crit_exit(); 925 if (tobject->backing_object == NULL) 926 continue; 927 tpindex += OFF_TO_IDX(tobject->backing_object_offset); 928 tobject = tobject->backing_object; 929 goto shadowlookup; 930 } 931 932 /* 933 * If the page is busy or not in a normal active state, 934 * we skip it. If the page is not managed there are no 935 * page queues to mess with. Things can break if we mess 936 * with pages in any of the below states. 937 */ 938 if ( 939 m->hold_count || 940 m->wire_count || 941 (m->flags & PG_UNMANAGED) || 942 m->valid != VM_PAGE_BITS_ALL 943 ) { 944 crit_exit(); 945 continue; 946 } 947 948 if (vm_page_sleep_busy(m, TRUE, "madvpo")) { 949 crit_exit(); 950 goto relookup; 951 } 952 crit_exit(); 953 954 /* 955 * Theoretically once a page is known not to be busy, an 956 * interrupt cannot come along and rip it out from under us. 957 */ 958 959 if (advise == MADV_WILLNEED) { 960 vm_page_activate(m); 961 } else if (advise == MADV_DONTNEED) { 962 vm_page_dontneed(m); 963 } else if (advise == MADV_FREE) { 964 /* 965 * Mark the page clean. This will allow the page 966 * to be freed up by the system. However, such pages 967 * are often reused quickly by malloc()/free() 968 * so we do not do anything that would cause 969 * a page fault if we can help it. 970 * 971 * Specifically, we do not try to actually free 972 * the page now nor do we try to put it in the 973 * cache (which would cause a page fault on reuse). 974 * 975 * But we do make the page is freeable as we 976 * can without actually taking the step of unmapping 977 * it. 978 */ 979 pmap_clear_modify(m); 980 m->dirty = 0; 981 m->act_count = 0; 982 vm_page_dontneed(m); 983 if (tobject->type == OBJT_SWAP) 984 swap_pager_freespace(tobject, tpindex, 1); 985 } 986 } 987 } 988 989 /* 990 * vm_object_shadow: 991 * 992 * Create a new object which is backed by the 993 * specified existing object range. The source 994 * object reference is deallocated. 995 * 996 * The new object and offset into that object 997 * are returned in the source parameters. 998 */ 999 1000 void 1001 vm_object_shadow(vm_object_t *object, /* IN/OUT */ 1002 vm_ooffset_t *offset, /* IN/OUT */ 1003 vm_size_t length) 1004 { 1005 vm_object_t source; 1006 vm_object_t result; 1007 1008 source = *object; 1009 1010 /* 1011 * Don't create the new object if the old object isn't shared. 1012 */ 1013 1014 if (source != NULL && 1015 source->ref_count == 1 && 1016 source->handle == NULL && 1017 (source->type == OBJT_DEFAULT || 1018 source->type == OBJT_SWAP)) 1019 return; 1020 1021 /* 1022 * Allocate a new object with the given length 1023 */ 1024 1025 if ((result = vm_object_allocate(OBJT_DEFAULT, length)) == NULL) 1026 panic("vm_object_shadow: no object for shadowing"); 1027 1028 /* 1029 * The new object shadows the source object, adding a reference to it. 1030 * Our caller changes his reference to point to the new object, 1031 * removing a reference to the source object. Net result: no change 1032 * of reference count. 1033 * 1034 * Try to optimize the result object's page color when shadowing 1035 * in order to maintain page coloring consistency in the combined 1036 * shadowed object. 1037 */ 1038 result->backing_object = source; 1039 if (source) { 1040 LIST_INSERT_HEAD(&source->shadow_head, result, shadow_list); 1041 source->shadow_count++; 1042 source->generation++; 1043 result->pg_color = (source->pg_color + OFF_TO_IDX(*offset)) & PQ_L2_MASK; 1044 } 1045 1046 /* 1047 * Store the offset into the source object, and fix up the offset into 1048 * the new object. 1049 */ 1050 1051 result->backing_object_offset = *offset; 1052 1053 /* 1054 * Return the new things 1055 */ 1056 1057 *offset = 0; 1058 *object = result; 1059 } 1060 1061 #define OBSC_TEST_ALL_SHADOWED 0x0001 1062 #define OBSC_COLLAPSE_NOWAIT 0x0002 1063 #define OBSC_COLLAPSE_WAIT 0x0004 1064 1065 static int vm_object_backing_scan_callback(vm_page_t p, void *data); 1066 1067 static __inline int 1068 vm_object_backing_scan(vm_object_t object, int op) 1069 { 1070 struct rb_vm_page_scan_info info; 1071 vm_object_t backing_object; 1072 1073 /* 1074 * spl protection is required to avoid races between the memq/lookup, 1075 * an interrupt doing an unbusy/free, and our busy check. Amoung 1076 * other things. 1077 */ 1078 crit_enter(); 1079 1080 backing_object = object->backing_object; 1081 info.backing_offset_index = OFF_TO_IDX(object->backing_object_offset); 1082 1083 /* 1084 * Initial conditions 1085 */ 1086 1087 if (op & OBSC_TEST_ALL_SHADOWED) { 1088 /* 1089 * We do not want to have to test for the existence of 1090 * swap pages in the backing object. XXX but with the 1091 * new swapper this would be pretty easy to do. 1092 * 1093 * XXX what about anonymous MAP_SHARED memory that hasn't 1094 * been ZFOD faulted yet? If we do not test for this, the 1095 * shadow test may succeed! XXX 1096 */ 1097 if (backing_object->type != OBJT_DEFAULT) { 1098 crit_exit(); 1099 return(0); 1100 } 1101 } 1102 if (op & OBSC_COLLAPSE_WAIT) { 1103 KKASSERT((backing_object->flags & OBJ_DEAD) == 0); 1104 vm_object_set_flag(backing_object, OBJ_DEAD); 1105 } 1106 1107 /* 1108 * Our scan. We have to retry if a negative error code is returned, 1109 * otherwise 0 or 1 will be returned in info.error. 0 Indicates that 1110 * the scan had to be stopped because the parent does not completely 1111 * shadow the child. 1112 */ 1113 info.object = object; 1114 info.backing_object = backing_object; 1115 info.limit = op; 1116 do { 1117 info.error = 1; 1118 vm_page_rb_tree_RB_SCAN(&backing_object->rb_memq, NULL, 1119 vm_object_backing_scan_callback, 1120 &info); 1121 } while (info.error < 0); 1122 crit_exit(); 1123 return(info.error); 1124 } 1125 1126 static int 1127 vm_object_backing_scan_callback(vm_page_t p, void *data) 1128 { 1129 struct rb_vm_page_scan_info *info = data; 1130 vm_object_t backing_object; 1131 vm_object_t object; 1132 vm_pindex_t new_pindex; 1133 vm_pindex_t backing_offset_index; 1134 int op; 1135 1136 new_pindex = p->pindex - info->backing_offset_index; 1137 op = info->limit; 1138 object = info->object; 1139 backing_object = info->backing_object; 1140 backing_offset_index = info->backing_offset_index; 1141 1142 if (op & OBSC_TEST_ALL_SHADOWED) { 1143 vm_page_t pp; 1144 1145 /* 1146 * Ignore pages outside the parent object's range 1147 * and outside the parent object's mapping of the 1148 * backing object. 1149 * 1150 * note that we do not busy the backing object's 1151 * page. 1152 */ 1153 if ( 1154 p->pindex < backing_offset_index || 1155 new_pindex >= object->size 1156 ) { 1157 return(0); 1158 } 1159 1160 /* 1161 * See if the parent has the page or if the parent's 1162 * object pager has the page. If the parent has the 1163 * page but the page is not valid, the parent's 1164 * object pager must have the page. 1165 * 1166 * If this fails, the parent does not completely shadow 1167 * the object and we might as well give up now. 1168 */ 1169 1170 pp = vm_page_lookup(object, new_pindex); 1171 if ( 1172 (pp == NULL || pp->valid == 0) && 1173 !vm_pager_has_page(object, new_pindex, NULL, NULL) 1174 ) { 1175 info->error = 0; /* problemo */ 1176 return(-1); /* stop the scan */ 1177 } 1178 } 1179 1180 /* 1181 * Check for busy page 1182 */ 1183 1184 if (op & (OBSC_COLLAPSE_WAIT | OBSC_COLLAPSE_NOWAIT)) { 1185 vm_page_t pp; 1186 1187 if (op & OBSC_COLLAPSE_NOWAIT) { 1188 if ( 1189 (p->flags & PG_BUSY) || 1190 !p->valid || 1191 p->hold_count || 1192 p->wire_count || 1193 p->busy 1194 ) { 1195 return(0); 1196 } 1197 } else if (op & OBSC_COLLAPSE_WAIT) { 1198 if (vm_page_sleep_busy(p, TRUE, "vmocol")) { 1199 /* 1200 * If we slept, anything could have 1201 * happened. Ask that the scan be restarted. 1202 * 1203 * Since the object is marked dead, the 1204 * backing offset should not have changed. 1205 */ 1206 info->error = -1; 1207 return(-1); 1208 } 1209 } 1210 1211 /* 1212 * Busy the page 1213 */ 1214 vm_page_busy(p); 1215 1216 KASSERT( 1217 p->object == backing_object, 1218 ("vm_object_qcollapse(): object mismatch") 1219 ); 1220 1221 /* 1222 * Destroy any associated swap 1223 */ 1224 if (backing_object->type == OBJT_SWAP) { 1225 swap_pager_freespace( 1226 backing_object, 1227 p->pindex, 1228 1 1229 ); 1230 } 1231 1232 if ( 1233 p->pindex < backing_offset_index || 1234 new_pindex >= object->size 1235 ) { 1236 /* 1237 * Page is out of the parent object's range, we 1238 * can simply destroy it. 1239 */ 1240 vm_page_protect(p, VM_PROT_NONE); 1241 vm_page_free(p); 1242 return(0); 1243 } 1244 1245 pp = vm_page_lookup(object, new_pindex); 1246 if ( 1247 pp != NULL || 1248 vm_pager_has_page(object, new_pindex, NULL, NULL) 1249 ) { 1250 /* 1251 * page already exists in parent OR swap exists 1252 * for this location in the parent. Destroy 1253 * the original page from the backing object. 1254 * 1255 * Leave the parent's page alone 1256 */ 1257 vm_page_protect(p, VM_PROT_NONE); 1258 vm_page_free(p); 1259 return(0); 1260 } 1261 1262 /* 1263 * Page does not exist in parent, rename the 1264 * page from the backing object to the main object. 1265 * 1266 * If the page was mapped to a process, it can remain 1267 * mapped through the rename. 1268 */ 1269 if ((p->queue - p->pc) == PQ_CACHE) 1270 vm_page_deactivate(p); 1271 1272 vm_page_rename(p, object, new_pindex); 1273 /* page automatically made dirty by rename */ 1274 } 1275 return(0); 1276 } 1277 1278 /* 1279 * this version of collapse allows the operation to occur earlier and 1280 * when paging_in_progress is true for an object... This is not a complete 1281 * operation, but should plug 99.9% of the rest of the leaks. 1282 */ 1283 static void 1284 vm_object_qcollapse(vm_object_t object) 1285 { 1286 vm_object_t backing_object = object->backing_object; 1287 1288 if (backing_object->ref_count != 1) 1289 return; 1290 1291 backing_object->ref_count += 2; 1292 1293 vm_object_backing_scan(object, OBSC_COLLAPSE_NOWAIT); 1294 1295 backing_object->ref_count -= 2; 1296 } 1297 1298 /* 1299 * vm_object_collapse: 1300 * 1301 * Collapse an object with the object backing it. 1302 * Pages in the backing object are moved into the 1303 * parent, and the backing object is deallocated. 1304 */ 1305 void 1306 vm_object_collapse(vm_object_t object) 1307 { 1308 while (TRUE) { 1309 vm_object_t backing_object; 1310 1311 /* 1312 * Verify that the conditions are right for collapse: 1313 * 1314 * The object exists and the backing object exists. 1315 */ 1316 if (object == NULL) 1317 break; 1318 1319 if ((backing_object = object->backing_object) == NULL) 1320 break; 1321 1322 /* 1323 * we check the backing object first, because it is most likely 1324 * not collapsable. 1325 */ 1326 if (backing_object->handle != NULL || 1327 (backing_object->type != OBJT_DEFAULT && 1328 backing_object->type != OBJT_SWAP) || 1329 (backing_object->flags & OBJ_DEAD) || 1330 object->handle != NULL || 1331 (object->type != OBJT_DEFAULT && 1332 object->type != OBJT_SWAP) || 1333 (object->flags & OBJ_DEAD)) { 1334 break; 1335 } 1336 1337 if ( 1338 object->paging_in_progress != 0 || 1339 backing_object->paging_in_progress != 0 1340 ) { 1341 vm_object_qcollapse(object); 1342 break; 1343 } 1344 1345 /* 1346 * We know that we can either collapse the backing object (if 1347 * the parent is the only reference to it) or (perhaps) have 1348 * the parent bypass the object if the parent happens to shadow 1349 * all the resident pages in the entire backing object. 1350 * 1351 * This is ignoring pager-backed pages such as swap pages. 1352 * vm_object_backing_scan fails the shadowing test in this 1353 * case. 1354 */ 1355 1356 if (backing_object->ref_count == 1) { 1357 /* 1358 * If there is exactly one reference to the backing 1359 * object, we can collapse it into the parent. 1360 */ 1361 vm_object_backing_scan(object, OBSC_COLLAPSE_WAIT); 1362 1363 /* 1364 * Move the pager from backing_object to object. 1365 */ 1366 1367 if (backing_object->type == OBJT_SWAP) { 1368 vm_object_pip_add(backing_object, 1); 1369 1370 /* 1371 * scrap the paging_offset junk and do a 1372 * discrete copy. This also removes major 1373 * assumptions about how the swap-pager 1374 * works from where it doesn't belong. The 1375 * new swapper is able to optimize the 1376 * destroy-source case. 1377 */ 1378 1379 vm_object_pip_add(object, 1); 1380 swap_pager_copy( 1381 backing_object, 1382 object, 1383 OFF_TO_IDX(object->backing_object_offset), TRUE); 1384 vm_object_pip_wakeup(object); 1385 1386 vm_object_pip_wakeup(backing_object); 1387 } 1388 /* 1389 * Object now shadows whatever backing_object did. 1390 * Note that the reference to 1391 * backing_object->backing_object moves from within 1392 * backing_object to within object. 1393 */ 1394 1395 LIST_REMOVE(object, shadow_list); 1396 object->backing_object->shadow_count--; 1397 object->backing_object->generation++; 1398 if (backing_object->backing_object) { 1399 LIST_REMOVE(backing_object, shadow_list); 1400 backing_object->backing_object->shadow_count--; 1401 backing_object->backing_object->generation++; 1402 } 1403 object->backing_object = backing_object->backing_object; 1404 if (object->backing_object) { 1405 LIST_INSERT_HEAD( 1406 &object->backing_object->shadow_head, 1407 object, 1408 shadow_list 1409 ); 1410 object->backing_object->shadow_count++; 1411 object->backing_object->generation++; 1412 } 1413 1414 object->backing_object_offset += 1415 backing_object->backing_object_offset; 1416 1417 /* 1418 * Discard backing_object. 1419 * 1420 * Since the backing object has no pages, no pager left, 1421 * and no object references within it, all that is 1422 * necessary is to dispose of it. 1423 */ 1424 1425 KASSERT(backing_object->ref_count == 1, ("backing_object %p was somehow re-referenced during collapse!", backing_object)); 1426 KASSERT(RB_EMPTY(&backing_object->rb_memq), ("backing_object %p somehow has left over pages during collapse!", backing_object)); 1427 crit_enter(); 1428 TAILQ_REMOVE( 1429 &vm_object_list, 1430 backing_object, 1431 object_list 1432 ); 1433 vm_object_count--; 1434 crit_exit(); 1435 1436 zfree(obj_zone, backing_object); 1437 1438 object_collapses++; 1439 } else { 1440 vm_object_t new_backing_object; 1441 1442 /* 1443 * If we do not entirely shadow the backing object, 1444 * there is nothing we can do so we give up. 1445 */ 1446 1447 if (vm_object_backing_scan(object, OBSC_TEST_ALL_SHADOWED) == 0) { 1448 break; 1449 } 1450 1451 /* 1452 * Make the parent shadow the next object in the 1453 * chain. Deallocating backing_object will not remove 1454 * it, since its reference count is at least 2. 1455 */ 1456 1457 LIST_REMOVE(object, shadow_list); 1458 backing_object->shadow_count--; 1459 backing_object->generation++; 1460 1461 new_backing_object = backing_object->backing_object; 1462 if ((object->backing_object = new_backing_object) != NULL) { 1463 vm_object_reference(new_backing_object); 1464 LIST_INSERT_HEAD( 1465 &new_backing_object->shadow_head, 1466 object, 1467 shadow_list 1468 ); 1469 new_backing_object->shadow_count++; 1470 new_backing_object->generation++; 1471 object->backing_object_offset += 1472 backing_object->backing_object_offset; 1473 } 1474 1475 /* 1476 * Drop the reference count on backing_object. Since 1477 * its ref_count was at least 2, it will not vanish; 1478 * so we don't need to call vm_object_deallocate, but 1479 * we do anyway. 1480 */ 1481 vm_object_deallocate(backing_object); 1482 object_bypasses++; 1483 } 1484 1485 /* 1486 * Try again with this object's new backing object. 1487 */ 1488 } 1489 } 1490 1491 /* 1492 * vm_object_page_remove: [internal] 1493 * 1494 * Removes all physical pages in the specified 1495 * object range from the object's list of pages. 1496 */ 1497 static int vm_object_page_remove_callback(vm_page_t p, void *data); 1498 1499 void 1500 vm_object_page_remove(vm_object_t object, vm_pindex_t start, vm_pindex_t end, 1501 boolean_t clean_only) 1502 { 1503 struct rb_vm_page_scan_info info; 1504 int all; 1505 1506 /* 1507 * Degenerate cases and assertions 1508 */ 1509 if (object == NULL || object->resident_page_count == 0) 1510 return; 1511 KASSERT(object->type != OBJT_PHYS, 1512 ("attempt to remove pages from a physical object")); 1513 1514 /* 1515 * Indicate that paging is occuring on the object 1516 */ 1517 crit_enter(); 1518 vm_object_pip_add(object, 1); 1519 1520 /* 1521 * Figure out the actual removal range and whether we are removing 1522 * the entire contents of the object or not. If removing the entire 1523 * contents, be sure to get all pages, even those that might be 1524 * beyond the end of the object. 1525 */ 1526 info.start_pindex = start; 1527 if (end == 0) 1528 info.end_pindex = (vm_pindex_t)-1; 1529 else 1530 info.end_pindex = end - 1; 1531 info.limit = clean_only; 1532 all = (start == 0 && info.end_pindex >= object->size - 1); 1533 1534 /* 1535 * Loop until we are sure we have gotten them all. 1536 */ 1537 do { 1538 info.error = 0; 1539 vm_page_rb_tree_RB_SCAN(&object->rb_memq, rb_vm_page_scancmp, 1540 vm_object_page_remove_callback, &info); 1541 } while (info.error); 1542 1543 /* 1544 * Cleanup 1545 */ 1546 vm_object_pip_wakeup(object); 1547 crit_exit(); 1548 } 1549 1550 static int 1551 vm_object_page_remove_callback(vm_page_t p, void *data) 1552 { 1553 struct rb_vm_page_scan_info *info = data; 1554 1555 /* 1556 * Wired pages cannot be destroyed, but they can be invalidated 1557 * and we do so if clean_only (limit) is not set. 1558 */ 1559 if (p->wire_count != 0) { 1560 vm_page_protect(p, VM_PROT_NONE); 1561 if (info->limit == 0) 1562 p->valid = 0; 1563 return(0); 1564 } 1565 1566 /* 1567 * The busy flags are only cleared at 1568 * interrupt -- minimize the spl transitions 1569 */ 1570 1571 if (vm_page_sleep_busy(p, TRUE, "vmopar")) { 1572 info->error = 1; 1573 return(0); 1574 } 1575 1576 /* 1577 * limit is our clean_only flag. If set and the page is dirty, do 1578 * not free it. 1579 */ 1580 if (info->limit && p->valid) { 1581 vm_page_test_dirty(p); 1582 if (p->valid & p->dirty) 1583 return(0); 1584 } 1585 1586 /* 1587 * Destroy the page 1588 */ 1589 vm_page_busy(p); 1590 vm_page_protect(p, VM_PROT_NONE); 1591 vm_page_free(p); 1592 return(0); 1593 } 1594 1595 /* 1596 * Routine: vm_object_coalesce 1597 * Function: Coalesces two objects backing up adjoining 1598 * regions of memory into a single object. 1599 * 1600 * returns TRUE if objects were combined. 1601 * 1602 * NOTE: Only works at the moment if the second object is NULL - 1603 * if it's not, which object do we lock first? 1604 * 1605 * Parameters: 1606 * prev_object First object to coalesce 1607 * prev_offset Offset into prev_object 1608 * next_object Second object into coalesce 1609 * next_offset Offset into next_object 1610 * 1611 * prev_size Size of reference to prev_object 1612 * next_size Size of reference to next_object 1613 * 1614 * Conditions: 1615 * The object must *not* be locked. 1616 */ 1617 boolean_t 1618 vm_object_coalesce(vm_object_t prev_object, vm_pindex_t prev_pindex, 1619 vm_size_t prev_size, vm_size_t next_size) 1620 { 1621 vm_pindex_t next_pindex; 1622 1623 if (prev_object == NULL) { 1624 return (TRUE); 1625 } 1626 1627 if (prev_object->type != OBJT_DEFAULT && 1628 prev_object->type != OBJT_SWAP) { 1629 return (FALSE); 1630 } 1631 1632 /* 1633 * Try to collapse the object first 1634 */ 1635 vm_object_collapse(prev_object); 1636 1637 /* 1638 * Can't coalesce if: . more than one reference . paged out . shadows 1639 * another object . has a copy elsewhere (any of which mean that the 1640 * pages not mapped to prev_entry may be in use anyway) 1641 */ 1642 1643 if (prev_object->backing_object != NULL) { 1644 return (FALSE); 1645 } 1646 1647 prev_size >>= PAGE_SHIFT; 1648 next_size >>= PAGE_SHIFT; 1649 next_pindex = prev_pindex + prev_size; 1650 1651 if ((prev_object->ref_count > 1) && 1652 (prev_object->size != next_pindex)) { 1653 return (FALSE); 1654 } 1655 1656 /* 1657 * Remove any pages that may still be in the object from a previous 1658 * deallocation. 1659 */ 1660 if (next_pindex < prev_object->size) { 1661 vm_object_page_remove(prev_object, 1662 next_pindex, 1663 next_pindex + next_size, FALSE); 1664 if (prev_object->type == OBJT_SWAP) 1665 swap_pager_freespace(prev_object, 1666 next_pindex, next_size); 1667 } 1668 1669 /* 1670 * Extend the object if necessary. 1671 */ 1672 if (next_pindex + next_size > prev_object->size) 1673 prev_object->size = next_pindex + next_size; 1674 1675 return (TRUE); 1676 } 1677 1678 void 1679 vm_object_set_writeable_dirty(vm_object_t object) 1680 { 1681 struct vnode *vp; 1682 1683 vm_object_set_flag(object, OBJ_WRITEABLE|OBJ_MIGHTBEDIRTY); 1684 if (object->type == OBJT_VNODE && 1685 (vp = (struct vnode *)object->handle) != NULL) { 1686 if ((vp->v_flag & VOBJDIRTY) == 0) { 1687 vsetflags(vp, VOBJDIRTY); 1688 } 1689 } 1690 } 1691 1692 1693 1694 #include "opt_ddb.h" 1695 #ifdef DDB 1696 #include <sys/kernel.h> 1697 1698 #include <sys/cons.h> 1699 1700 #include <ddb/ddb.h> 1701 1702 static int _vm_object_in_map (vm_map_t map, vm_object_t object, 1703 vm_map_entry_t entry); 1704 static int vm_object_in_map (vm_object_t object); 1705 1706 static int 1707 _vm_object_in_map(vm_map_t map, vm_object_t object, vm_map_entry_t entry) 1708 { 1709 vm_map_t tmpm; 1710 vm_map_entry_t tmpe; 1711 vm_object_t obj; 1712 int entcount; 1713 1714 if (map == 0) 1715 return 0; 1716 if (entry == 0) { 1717 tmpe = map->header.next; 1718 entcount = map->nentries; 1719 while (entcount-- && (tmpe != &map->header)) { 1720 if( _vm_object_in_map(map, object, tmpe)) { 1721 return 1; 1722 } 1723 tmpe = tmpe->next; 1724 } 1725 return (0); 1726 } 1727 switch(entry->maptype) { 1728 case VM_MAPTYPE_SUBMAP: 1729 tmpm = entry->object.sub_map; 1730 tmpe = tmpm->header.next; 1731 entcount = tmpm->nentries; 1732 while (entcount-- && tmpe != &tmpm->header) { 1733 if( _vm_object_in_map(tmpm, object, tmpe)) { 1734 return 1; 1735 } 1736 tmpe = tmpe->next; 1737 } 1738 break; 1739 case VM_MAPTYPE_NORMAL: 1740 case VM_MAPTYPE_VPAGETABLE: 1741 obj = entry->object.vm_object; 1742 while (obj) { 1743 if (obj == object) 1744 return 1; 1745 obj = obj->backing_object; 1746 } 1747 break; 1748 default: 1749 break; 1750 } 1751 return 0; 1752 } 1753 1754 static int vm_object_in_map_callback(struct proc *p, void *data); 1755 1756 struct vm_object_in_map_info { 1757 vm_object_t object; 1758 int rv; 1759 }; 1760 1761 static int 1762 vm_object_in_map(vm_object_t object) 1763 { 1764 struct vm_object_in_map_info info; 1765 1766 info.rv = 0; 1767 info.object = object; 1768 1769 allproc_scan(vm_object_in_map_callback, &info); 1770 if (info.rv) 1771 return 1; 1772 if( _vm_object_in_map(&kernel_map, object, 0)) 1773 return 1; 1774 if( _vm_object_in_map(&pager_map, object, 0)) 1775 return 1; 1776 if( _vm_object_in_map(&buffer_map, object, 0)) 1777 return 1; 1778 return 0; 1779 } 1780 1781 static int 1782 vm_object_in_map_callback(struct proc *p, void *data) 1783 { 1784 struct vm_object_in_map_info *info = data; 1785 1786 if (p->p_vmspace) { 1787 if (_vm_object_in_map(&p->p_vmspace->vm_map, info->object, 0)) { 1788 info->rv = 1; 1789 return -1; 1790 } 1791 } 1792 return (0); 1793 } 1794 1795 DB_SHOW_COMMAND(vmochk, vm_object_check) 1796 { 1797 vm_object_t object; 1798 1799 /* 1800 * make sure that internal objs are in a map somewhere 1801 * and none have zero ref counts. 1802 */ 1803 for (object = TAILQ_FIRST(&vm_object_list); 1804 object != NULL; 1805 object = TAILQ_NEXT(object, object_list)) { 1806 if (object->handle == NULL && 1807 (object->type == OBJT_DEFAULT || object->type == OBJT_SWAP)) { 1808 if (object->ref_count == 0) { 1809 db_printf("vmochk: internal obj has zero ref count: %ld\n", 1810 (long)object->size); 1811 } 1812 if (!vm_object_in_map(object)) { 1813 db_printf( 1814 "vmochk: internal obj is not in a map: " 1815 "ref: %d, size: %lu: 0x%lx, backing_object: %p\n", 1816 object->ref_count, (u_long)object->size, 1817 (u_long)object->size, 1818 (void *)object->backing_object); 1819 } 1820 } 1821 } 1822 } 1823 1824 /* 1825 * vm_object_print: [ debug ] 1826 */ 1827 DB_SHOW_COMMAND(object, vm_object_print_static) 1828 { 1829 /* XXX convert args. */ 1830 vm_object_t object = (vm_object_t)addr; 1831 boolean_t full = have_addr; 1832 1833 vm_page_t p; 1834 1835 /* XXX count is an (unused) arg. Avoid shadowing it. */ 1836 #define count was_count 1837 1838 int count; 1839 1840 if (object == NULL) 1841 return; 1842 1843 db_iprintf( 1844 "Object %p: type=%d, size=0x%lx, res=%d, ref=%d, flags=0x%x\n", 1845 object, (int)object->type, (u_long)object->size, 1846 object->resident_page_count, object->ref_count, object->flags); 1847 /* 1848 * XXX no %qd in kernel. Truncate object->backing_object_offset. 1849 */ 1850 db_iprintf(" sref=%d, backing_object(%d)=(%p)+0x%lx\n", 1851 object->shadow_count, 1852 object->backing_object ? object->backing_object->ref_count : 0, 1853 object->backing_object, (long)object->backing_object_offset); 1854 1855 if (!full) 1856 return; 1857 1858 db_indent += 2; 1859 count = 0; 1860 RB_FOREACH(p, vm_page_rb_tree, &object->rb_memq) { 1861 if (count == 0) 1862 db_iprintf("memory:="); 1863 else if (count == 6) { 1864 db_printf("\n"); 1865 db_iprintf(" ..."); 1866 count = 0; 1867 } else 1868 db_printf(","); 1869 count++; 1870 1871 db_printf("(off=0x%lx,page=0x%lx)", 1872 (u_long) p->pindex, (u_long) VM_PAGE_TO_PHYS(p)); 1873 } 1874 if (count != 0) 1875 db_printf("\n"); 1876 db_indent -= 2; 1877 } 1878 1879 /* XXX. */ 1880 #undef count 1881 1882 /* XXX need this non-static entry for calling from vm_map_print. */ 1883 void 1884 vm_object_print(/* db_expr_t */ long addr, 1885 boolean_t have_addr, 1886 /* db_expr_t */ long count, 1887 char *modif) 1888 { 1889 vm_object_print_static(addr, have_addr, count, modif); 1890 } 1891 1892 DB_SHOW_COMMAND(vmopag, vm_object_print_pages) 1893 { 1894 vm_object_t object; 1895 int nl = 0; 1896 int c; 1897 for (object = TAILQ_FIRST(&vm_object_list); 1898 object != NULL; 1899 object = TAILQ_NEXT(object, object_list)) { 1900 vm_pindex_t idx, fidx; 1901 vm_pindex_t osize; 1902 vm_paddr_t pa = -1, padiff; 1903 int rcount; 1904 vm_page_t m; 1905 1906 db_printf("new object: %p\n", (void *)object); 1907 if ( nl > 18) { 1908 c = cngetc(); 1909 if (c != ' ') 1910 return; 1911 nl = 0; 1912 } 1913 nl++; 1914 rcount = 0; 1915 fidx = 0; 1916 osize = object->size; 1917 if (osize > 128) 1918 osize = 128; 1919 for (idx = 0; idx < osize; idx++) { 1920 m = vm_page_lookup(object, idx); 1921 if (m == NULL) { 1922 if (rcount) { 1923 db_printf(" index(%ld)run(%d)pa(0x%lx)\n", 1924 (long)fidx, rcount, (long)pa); 1925 if ( nl > 18) { 1926 c = cngetc(); 1927 if (c != ' ') 1928 return; 1929 nl = 0; 1930 } 1931 nl++; 1932 rcount = 0; 1933 } 1934 continue; 1935 } 1936 1937 1938 if (rcount && 1939 (VM_PAGE_TO_PHYS(m) == pa + rcount * PAGE_SIZE)) { 1940 ++rcount; 1941 continue; 1942 } 1943 if (rcount) { 1944 padiff = pa + rcount * PAGE_SIZE - VM_PAGE_TO_PHYS(m); 1945 padiff >>= PAGE_SHIFT; 1946 padiff &= PQ_L2_MASK; 1947 if (padiff == 0) { 1948 pa = VM_PAGE_TO_PHYS(m) - rcount * PAGE_SIZE; 1949 ++rcount; 1950 continue; 1951 } 1952 db_printf(" index(%ld)run(%d)pa(0x%lx)", 1953 (long)fidx, rcount, (long)pa); 1954 db_printf("pd(%ld)\n", (long)padiff); 1955 if ( nl > 18) { 1956 c = cngetc(); 1957 if (c != ' ') 1958 return; 1959 nl = 0; 1960 } 1961 nl++; 1962 } 1963 fidx = idx; 1964 pa = VM_PAGE_TO_PHYS(m); 1965 rcount = 1; 1966 } 1967 if (rcount) { 1968 db_printf(" index(%ld)run(%d)pa(0x%lx)\n", 1969 (long)fidx, rcount, (long)pa); 1970 if ( nl > 18) { 1971 c = cngetc(); 1972 if (c != ' ') 1973 return; 1974 nl = 0; 1975 } 1976 nl++; 1977 } 1978 } 1979 } 1980 #endif /* DDB */ 1981