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 1.25 2006/05/25 07:36:37 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 #define MSYNC_FLUSH_HARDSEQ 0x01 98 #define MSYNC_FLUSH_SOFTSEQ 0x02 99 100 static int msync_flush_flags = MSYNC_FLUSH_HARDSEQ | MSYNC_FLUSH_SOFTSEQ; 101 SYSCTL_INT(_vm, OID_AUTO, msync_flush_flags, 102 CTLFLAG_RW, &msync_flush_flags, 0, ""); 103 104 static void vm_object_qcollapse (vm_object_t object); 105 static int vm_object_page_collect_flush(vm_object_t object, vm_page_t p, int curgeneration, int pagerflags); 106 107 /* 108 * Virtual memory objects maintain the actual data 109 * associated with allocated virtual memory. A given 110 * page of memory exists within exactly one object. 111 * 112 * An object is only deallocated when all "references" 113 * are given up. Only one "reference" to a given 114 * region of an object should be writeable. 115 * 116 * Associated with each object is a list of all resident 117 * memory pages belonging to that object; this list is 118 * maintained by the "vm_page" module, and locked by the object's 119 * lock. 120 * 121 * Each object also records a "pager" routine which is 122 * used to retrieve (and store) pages to the proper backing 123 * storage. In addition, objects may be backed by other 124 * objects from which they were virtual-copied. 125 * 126 * The only items within the object structure which are 127 * modified after time of creation are: 128 * reference count locked by object's lock 129 * pager routine locked by object's lock 130 * 131 */ 132 133 struct object_q vm_object_list; 134 static long vm_object_count; /* count of all objects */ 135 vm_object_t kernel_object; 136 vm_object_t kmem_object; 137 static struct vm_object kernel_object_store; 138 static struct vm_object kmem_object_store; 139 extern int vm_pageout_page_count; 140 141 static long object_collapses; 142 static long object_bypasses; 143 static int next_index; 144 static vm_zone_t obj_zone; 145 static struct vm_zone obj_zone_store; 146 static int object_hash_rand; 147 #define VM_OBJECTS_INIT 256 148 static struct vm_object vm_objects_init[VM_OBJECTS_INIT]; 149 150 void 151 _vm_object_allocate(objtype_t type, vm_size_t size, vm_object_t object) 152 { 153 int incr; 154 TAILQ_INIT(&object->memq); 155 LIST_INIT(&object->shadow_head); 156 157 object->type = type; 158 object->size = size; 159 object->ref_count = 1; 160 object->flags = 0; 161 if ((object->type == OBJT_DEFAULT) || (object->type == OBJT_SWAP)) 162 vm_object_set_flag(object, OBJ_ONEMAPPING); 163 object->paging_in_progress = 0; 164 object->resident_page_count = 0; 165 object->shadow_count = 0; 166 object->pg_color = next_index; 167 if ( size > (PQ_L2_SIZE / 3 + PQ_PRIME1)) 168 incr = PQ_L2_SIZE / 3 + PQ_PRIME1; 169 else 170 incr = size; 171 next_index = (next_index + incr) & PQ_L2_MASK; 172 object->handle = NULL; 173 object->backing_object = NULL; 174 object->backing_object_offset = (vm_ooffset_t) 0; 175 /* 176 * Try to generate a number that will spread objects out in the 177 * hash table. We 'wipe' new objects across the hash in 128 page 178 * increments plus 1 more to offset it a little more by the time 179 * it wraps around. 180 */ 181 object->hash_rand = object_hash_rand - 129; 182 183 object->generation++; 184 185 crit_enter(); 186 TAILQ_INSERT_TAIL(&vm_object_list, object, object_list); 187 vm_object_count++; 188 object_hash_rand = object->hash_rand; 189 crit_exit(); 190 } 191 192 /* 193 * vm_object_init: 194 * 195 * Initialize the VM objects module. 196 */ 197 void 198 vm_object_init(void) 199 { 200 TAILQ_INIT(&vm_object_list); 201 202 kernel_object = &kernel_object_store; 203 _vm_object_allocate(OBJT_DEFAULT, OFF_TO_IDX(VM_MAX_KERNEL_ADDRESS - VM_MIN_KERNEL_ADDRESS), 204 kernel_object); 205 206 kmem_object = &kmem_object_store; 207 _vm_object_allocate(OBJT_DEFAULT, OFF_TO_IDX(VM_MAX_KERNEL_ADDRESS - VM_MIN_KERNEL_ADDRESS), 208 kmem_object); 209 210 obj_zone = &obj_zone_store; 211 zbootinit(obj_zone, "VM OBJECT", sizeof (struct vm_object), 212 vm_objects_init, VM_OBJECTS_INIT); 213 } 214 215 void 216 vm_object_init2(void) 217 { 218 zinitna(obj_zone, NULL, NULL, 0, 0, ZONE_PANICFAIL, 1); 219 } 220 221 /* 222 * vm_object_allocate: 223 * 224 * Returns a new object with the given size. 225 */ 226 227 vm_object_t 228 vm_object_allocate(objtype_t type, vm_size_t size) 229 { 230 vm_object_t result; 231 232 result = (vm_object_t) zalloc(obj_zone); 233 234 _vm_object_allocate(type, size, result); 235 236 return (result); 237 } 238 239 240 /* 241 * vm_object_reference: 242 * 243 * Gets another reference to the given object. 244 */ 245 void 246 vm_object_reference(vm_object_t object) 247 { 248 if (object == NULL) 249 return; 250 251 object->ref_count++; 252 if (object->type == OBJT_VNODE) { 253 vref(object->handle); 254 /* XXX what if the vnode is being destroyed? */ 255 } 256 } 257 258 static void 259 vm_object_vndeallocate(vm_object_t object) 260 { 261 struct vnode *vp = (struct vnode *) object->handle; 262 263 KASSERT(object->type == OBJT_VNODE, 264 ("vm_object_vndeallocate: not a vnode object")); 265 KASSERT(vp != NULL, ("vm_object_vndeallocate: missing vp")); 266 #ifdef INVARIANTS 267 if (object->ref_count == 0) { 268 vprint("vm_object_vndeallocate", vp); 269 panic("vm_object_vndeallocate: bad object reference count"); 270 } 271 #endif 272 273 object->ref_count--; 274 if (object->ref_count == 0) 275 vp->v_flag &= ~VTEXT; 276 vrele(vp); 277 } 278 279 /* 280 * vm_object_deallocate: 281 * 282 * Release a reference to the specified object, 283 * gained either through a vm_object_allocate 284 * or a vm_object_reference call. When all references 285 * are gone, storage associated with this object 286 * may be relinquished. 287 * 288 * No object may be locked. 289 */ 290 void 291 vm_object_deallocate(vm_object_t object) 292 { 293 vm_object_t temp; 294 295 while (object != NULL) { 296 if (object->type == OBJT_VNODE) { 297 vm_object_vndeallocate(object); 298 return; 299 } 300 301 if (object->ref_count == 0) { 302 panic("vm_object_deallocate: object deallocated too many times: %d", object->type); 303 } else if (object->ref_count > 2) { 304 object->ref_count--; 305 return; 306 } 307 308 /* 309 * Here on ref_count of one or two, which are special cases for 310 * objects. 311 */ 312 if ((object->ref_count == 2) && (object->shadow_count == 0)) { 313 vm_object_set_flag(object, OBJ_ONEMAPPING); 314 object->ref_count--; 315 return; 316 } else if ((object->ref_count == 2) && (object->shadow_count == 1)) { 317 object->ref_count--; 318 if ((object->handle == NULL) && 319 (object->type == OBJT_DEFAULT || 320 object->type == OBJT_SWAP)) { 321 vm_object_t robject; 322 323 robject = LIST_FIRST(&object->shadow_head); 324 KASSERT(robject != NULL, 325 ("vm_object_deallocate: ref_count: %d, shadow_count: %d", 326 object->ref_count, 327 object->shadow_count)); 328 if ((robject->handle == NULL) && 329 (robject->type == OBJT_DEFAULT || 330 robject->type == OBJT_SWAP)) { 331 332 robject->ref_count++; 333 334 while ( 335 robject->paging_in_progress || 336 object->paging_in_progress 337 ) { 338 vm_object_pip_sleep(robject, "objde1"); 339 vm_object_pip_sleep(object, "objde2"); 340 } 341 342 if (robject->ref_count == 1) { 343 robject->ref_count--; 344 object = robject; 345 goto doterm; 346 } 347 348 object = robject; 349 vm_object_collapse(object); 350 continue; 351 } 352 } 353 354 return; 355 356 } else { 357 object->ref_count--; 358 if (object->ref_count != 0) 359 return; 360 } 361 362 doterm: 363 364 temp = object->backing_object; 365 if (temp) { 366 LIST_REMOVE(object, shadow_list); 367 temp->shadow_count--; 368 temp->generation++; 369 object->backing_object = NULL; 370 } 371 372 /* 373 * Don't double-terminate, we could be in a termination 374 * recursion due to the terminate having to sync data 375 * to disk. 376 */ 377 if ((object->flags & OBJ_DEAD) == 0) 378 vm_object_terminate(object); 379 object = temp; 380 } 381 } 382 383 /* 384 * vm_object_terminate actually destroys the specified object, freeing 385 * up all previously used resources. 386 * 387 * The object must be locked. 388 * This routine may block. 389 */ 390 void 391 vm_object_terminate(vm_object_t object) 392 { 393 vm_page_t p; 394 395 /* 396 * Make sure no one uses us. 397 */ 398 vm_object_set_flag(object, OBJ_DEAD); 399 400 /* 401 * wait for the pageout daemon to be done with the object 402 */ 403 vm_object_pip_wait(object, "objtrm"); 404 405 KASSERT(!object->paging_in_progress, 406 ("vm_object_terminate: pageout in progress")); 407 408 /* 409 * Clean and free the pages, as appropriate. All references to the 410 * object are gone, so we don't need to lock it. 411 */ 412 if (object->type == OBJT_VNODE) { 413 struct vnode *vp; 414 415 /* 416 * Clean pages and flush buffers. 417 */ 418 vm_object_page_clean(object, 0, 0, OBJPC_SYNC); 419 420 vp = (struct vnode *) object->handle; 421 vinvalbuf(vp, V_SAVE, 0, 0); 422 } 423 424 /* 425 * Wait for any I/O to complete, after which there had better not 426 * be any references left on the object. 427 */ 428 vm_object_pip_wait(object, "objtrm"); 429 430 if (object->ref_count != 0) 431 panic("vm_object_terminate: object with references, ref_count=%d", object->ref_count); 432 433 /* 434 * Now free any remaining pages. For internal objects, this also 435 * removes them from paging queues. Don't free wired pages, just 436 * remove them from the object. 437 */ 438 crit_enter(); 439 while ((p = TAILQ_FIRST(&object->memq)) != NULL) { 440 if (p->busy || (p->flags & PG_BUSY)) 441 panic("vm_object_terminate: freeing busy page %p", p); 442 if (p->wire_count == 0) { 443 vm_page_busy(p); 444 vm_page_free(p); 445 mycpu->gd_cnt.v_pfree++; 446 } else { 447 vm_page_busy(p); 448 vm_page_remove(p); 449 vm_page_wakeup(p); 450 } 451 } 452 crit_exit(); 453 454 /* 455 * Let the pager know object is dead. 456 */ 457 vm_pager_deallocate(object); 458 459 /* 460 * Remove the object from the global object list. 461 */ 462 crit_enter(); 463 TAILQ_REMOVE(&vm_object_list, object, object_list); 464 vm_object_count--; 465 crit_exit(); 466 467 wakeup(object); 468 if (object->ref_count != 0) 469 panic("vm_object_terminate2: object with references, ref_count=%d", object->ref_count); 470 471 /* 472 * Free the space for the object. 473 */ 474 zfree(obj_zone, object); 475 } 476 477 /* 478 * vm_object_page_clean 479 * 480 * Clean all dirty pages in the specified range of object. Leaves page 481 * on whatever queue it is currently on. If NOSYNC is set then do not 482 * write out pages with PG_NOSYNC set (originally comes from MAP_NOSYNC), 483 * leaving the object dirty. 484 * 485 * When stuffing pages asynchronously, allow clustering. XXX we need a 486 * synchronous clustering mode implementation. 487 * 488 * Odd semantics: if start == end, we clean everything. 489 */ 490 491 void 492 vm_object_page_clean(vm_object_t object, vm_pindex_t start, vm_pindex_t end, 493 int flags) 494 { 495 vm_page_t p, np; 496 vm_offset_t tstart, tend; 497 vm_pindex_t pi; 498 struct vnode *vp; 499 int clearobjflags; 500 int pagerflags; 501 int curgeneration; 502 503 if (object->type != OBJT_VNODE || 504 (object->flags & OBJ_MIGHTBEDIRTY) == 0) 505 return; 506 507 pagerflags = (flags & (OBJPC_SYNC | OBJPC_INVAL)) ? VM_PAGER_PUT_SYNC : VM_PAGER_CLUSTER_OK; 508 pagerflags |= (flags & OBJPC_INVAL) ? VM_PAGER_PUT_INVAL : 0; 509 510 vp = object->handle; 511 512 vm_object_set_flag(object, OBJ_CLEANING); 513 514 /* 515 * Handle 'entire object' case 516 */ 517 tstart = start; 518 if (end == 0) { 519 tend = object->size; 520 } else { 521 tend = end; 522 } 523 524 /* 525 * If the caller is smart and only msync()s a range he knows is 526 * dirty, we may be able to avoid an object scan. This results in 527 * a phenominal improvement in performance. We cannot do this 528 * as a matter of course because the object may be huge - e.g. 529 * the size might be in the gigabytes or terrabytes. 530 */ 531 if (msync_flush_flags & MSYNC_FLUSH_HARDSEQ) { 532 vm_offset_t tscan; 533 int scanlimit; 534 int scanreset; 535 536 scanreset = object->resident_page_count / EASY_SCAN_FACTOR; 537 if (scanreset < 16) 538 scanreset = 16; 539 pagerflags |= VM_PAGER_IGNORE_CLEANCHK; 540 541 scanlimit = scanreset; 542 tscan = tstart; 543 544 /* 545 * spl protection is required despite the obj generation 546 * tracking because we cannot safely call vm_page_test_dirty() 547 * or avoid page field tests against an interrupt unbusy/free 548 * race that might occur prior to the busy check in 549 * vm_object_page_collect_flush(). 550 */ 551 crit_enter(); 552 while (tscan < tend) { 553 curgeneration = object->generation; 554 p = vm_page_lookup(object, tscan); 555 if (p == NULL || p->valid == 0 || 556 (p->queue - p->pc) == PQ_CACHE) { 557 if (--scanlimit == 0) 558 break; 559 ++tscan; 560 continue; 561 } 562 vm_page_test_dirty(p); 563 if ((p->dirty & p->valid) == 0) { 564 if (--scanlimit == 0) 565 break; 566 ++tscan; 567 continue; 568 } 569 /* 570 * If we have been asked to skip nosync pages and 571 * this is a nosync page, we can't continue. 572 */ 573 if ((flags & OBJPC_NOSYNC) && (p->flags & PG_NOSYNC)) { 574 if (--scanlimit == 0) 575 break; 576 ++tscan; 577 continue; 578 } 579 scanlimit = scanreset; 580 581 /* 582 * This returns 0 if it was unable to busy the first 583 * page (i.e. had to sleep). 584 */ 585 tscan += vm_object_page_collect_flush(object, p, 586 curgeneration, pagerflags); 587 } 588 crit_exit(); 589 590 /* 591 * If everything was dirty and we flushed it successfully, 592 * and the requested range is not the entire object, we 593 * don't have to mess with CLEANCHK or MIGHTBEDIRTY and can 594 * return immediately. 595 */ 596 if (tscan >= tend && (tstart || tend < object->size)) { 597 vm_object_clear_flag(object, OBJ_CLEANING); 598 return; 599 } 600 pagerflags &= ~VM_PAGER_IGNORE_CLEANCHK; 601 } 602 603 /* 604 * Generally set CLEANCHK interlock and make the page read-only so 605 * we can then clear the object flags. 606 * 607 * However, if this is a nosync mmap then the object is likely to 608 * stay dirty so do not mess with the page and do not clear the 609 * object flags. 610 * 611 * spl protection is required because an interrupt can remove page 612 * from the object. 613 */ 614 clearobjflags = 1; 615 616 crit_enter(); 617 for (p = TAILQ_FIRST(&object->memq); p; p = TAILQ_NEXT(p, listq)) { 618 vm_page_flag_set(p, PG_CLEANCHK); 619 if ((flags & OBJPC_NOSYNC) && (p->flags & PG_NOSYNC)) 620 clearobjflags = 0; 621 else 622 vm_page_protect(p, VM_PROT_READ); 623 } 624 crit_exit(); 625 626 if (clearobjflags && (tstart == 0) && (tend == object->size)) { 627 struct vnode *vp; 628 629 vm_object_clear_flag(object, OBJ_WRITEABLE|OBJ_MIGHTBEDIRTY); 630 if (object->type == OBJT_VNODE && 631 (vp = (struct vnode *)object->handle) != NULL) { 632 if (vp->v_flag & VOBJDIRTY) 633 vclrflags(vp, VOBJDIRTY); 634 } 635 } 636 637 /* 638 * spl protection is required both to avoid an interrupt unbusy/free 639 * race against a vm_page_lookup(), and also to ensure that the 640 * memq is consistent. We do not want a busy page to be ripped out 641 * from under us. 642 */ 643 crit_enter(); 644 rescan: 645 crit_exit(); 646 crit_enter(); 647 curgeneration = object->generation; 648 649 for (p = TAILQ_FIRST(&object->memq); p; p = np) { 650 int n; 651 652 np = TAILQ_NEXT(p, listq); 653 654 again: 655 pi = p->pindex; 656 if (((p->flags & PG_CLEANCHK) == 0) || 657 (pi < tstart) || (pi >= tend) || 658 (p->valid == 0) || 659 ((p->queue - p->pc) == PQ_CACHE)) { 660 vm_page_flag_clear(p, PG_CLEANCHK); 661 continue; 662 } 663 664 vm_page_test_dirty(p); 665 if ((p->dirty & p->valid) == 0) { 666 vm_page_flag_clear(p, PG_CLEANCHK); 667 continue; 668 } 669 670 /* 671 * If we have been asked to skip nosync pages and this is a 672 * nosync page, skip it. Note that the object flags were 673 * not cleared in this case so we do not have to set them. 674 */ 675 if ((flags & OBJPC_NOSYNC) && (p->flags & PG_NOSYNC)) { 676 vm_page_flag_clear(p, PG_CLEANCHK); 677 continue; 678 } 679 680 n = vm_object_page_collect_flush(object, p, 681 curgeneration, pagerflags); 682 if (n == 0) 683 goto rescan; 684 if (object->generation != curgeneration) 685 goto rescan; 686 687 /* 688 * Try to optimize the next page. If we can't we pick up 689 * our (random) scan where we left off. 690 */ 691 if (msync_flush_flags & MSYNC_FLUSH_SOFTSEQ) { 692 if ((p = vm_page_lookup(object, pi + n)) != NULL) 693 goto again; 694 } 695 } 696 crit_exit(); 697 698 vm_object_clear_flag(object, OBJ_CLEANING); 699 return; 700 } 701 702 /* 703 * This routine must be called within a critical section to properly avoid 704 * an interrupt unbusy/free race that can occur prior to the busy check. 705 * 706 * Using the object generation number here to detect page ripout is not 707 * the best idea in the world. XXX 708 * 709 * NOTE: we operate under the assumption that a page found to not be busy 710 * will not be ripped out from under us by an interrupt. XXX we should 711 * recode this to explicitly busy the pages. 712 */ 713 static int 714 vm_object_page_collect_flush(vm_object_t object, vm_page_t p, int curgeneration, int pagerflags) 715 { 716 int runlen; 717 int maxf; 718 int chkb; 719 int maxb; 720 int i; 721 vm_pindex_t pi; 722 vm_page_t maf[vm_pageout_page_count]; 723 vm_page_t mab[vm_pageout_page_count]; 724 vm_page_t ma[vm_pageout_page_count]; 725 726 pi = p->pindex; 727 while (vm_page_sleep_busy(p, TRUE, "vpcwai")) { 728 if (object->generation != curgeneration) { 729 return(0); 730 } 731 } 732 733 maxf = 0; 734 for(i = 1; i < vm_pageout_page_count; i++) { 735 vm_page_t tp; 736 737 if ((tp = vm_page_lookup(object, pi + i)) != NULL) { 738 if ((tp->flags & PG_BUSY) || 739 ((pagerflags & VM_PAGER_IGNORE_CLEANCHK) == 0 && 740 (tp->flags & PG_CLEANCHK) == 0) || 741 (tp->busy != 0)) 742 break; 743 if((tp->queue - tp->pc) == PQ_CACHE) { 744 vm_page_flag_clear(tp, PG_CLEANCHK); 745 break; 746 } 747 vm_page_test_dirty(tp); 748 if ((tp->dirty & tp->valid) == 0) { 749 vm_page_flag_clear(tp, PG_CLEANCHK); 750 break; 751 } 752 maf[ i - 1 ] = tp; 753 maxf++; 754 continue; 755 } 756 break; 757 } 758 759 maxb = 0; 760 chkb = vm_pageout_page_count - maxf; 761 if (chkb) { 762 for(i = 1; i < chkb;i++) { 763 vm_page_t tp; 764 765 if ((tp = vm_page_lookup(object, pi - i)) != NULL) { 766 if ((tp->flags & PG_BUSY) || 767 ((pagerflags & VM_PAGER_IGNORE_CLEANCHK) == 0 && 768 (tp->flags & PG_CLEANCHK) == 0) || 769 (tp->busy != 0)) 770 break; 771 if((tp->queue - tp->pc) == PQ_CACHE) { 772 vm_page_flag_clear(tp, PG_CLEANCHK); 773 break; 774 } 775 vm_page_test_dirty(tp); 776 if ((tp->dirty & tp->valid) == 0) { 777 vm_page_flag_clear(tp, PG_CLEANCHK); 778 break; 779 } 780 mab[ i - 1 ] = tp; 781 maxb++; 782 continue; 783 } 784 break; 785 } 786 } 787 788 for(i = 0; i < maxb; i++) { 789 int index = (maxb - i) - 1; 790 ma[index] = mab[i]; 791 vm_page_flag_clear(ma[index], PG_CLEANCHK); 792 } 793 vm_page_flag_clear(p, PG_CLEANCHK); 794 ma[maxb] = p; 795 for(i = 0; i < maxf; i++) { 796 int index = (maxb + i) + 1; 797 ma[index] = maf[i]; 798 vm_page_flag_clear(ma[index], PG_CLEANCHK); 799 } 800 runlen = maxb + maxf + 1; 801 802 vm_pageout_flush(ma, runlen, pagerflags); 803 for (i = 0; i < runlen; i++) { 804 if (ma[i]->valid & ma[i]->dirty) { 805 vm_page_protect(ma[i], VM_PROT_READ); 806 vm_page_flag_set(ma[i], PG_CLEANCHK); 807 808 /* 809 * maxf will end up being the actual number of pages 810 * we wrote out contiguously, non-inclusive of the 811 * first page. We do not count look-behind pages. 812 */ 813 if (i >= maxb + 1 && (maxf > i - maxb - 1)) 814 maxf = i - maxb - 1; 815 } 816 } 817 return(maxf + 1); 818 } 819 820 #ifdef not_used 821 /* XXX I cannot tell if this should be an exported symbol */ 822 /* 823 * vm_object_deactivate_pages 824 * 825 * Deactivate all pages in the specified object. (Keep its pages 826 * in memory even though it is no longer referenced.) 827 * 828 * The object must be locked. 829 */ 830 static void 831 vm_object_deactivate_pages(vm_object_t object) 832 { 833 vm_page_t p, next; 834 835 crit_enter(); 836 for (p = TAILQ_FIRST(&object->memq); p != NULL; p = next) { 837 next = TAILQ_NEXT(p, listq); 838 vm_page_deactivate(p); 839 } 840 crit_exit(); 841 } 842 #endif 843 844 /* 845 * Same as vm_object_pmap_copy, except range checking really 846 * works, and is meant for small sections of an object. 847 * 848 * This code protects resident pages by making them read-only 849 * and is typically called on a fork or split when a page 850 * is converted to copy-on-write. 851 * 852 * NOTE: If the page is already at VM_PROT_NONE, calling 853 * vm_page_protect will have no effect. 854 */ 855 void 856 vm_object_pmap_copy_1(vm_object_t object, vm_pindex_t start, vm_pindex_t end) 857 { 858 vm_pindex_t idx; 859 vm_page_t p; 860 861 if (object == NULL || (object->flags & OBJ_WRITEABLE) == 0) 862 return; 863 864 /* 865 * spl protection needed to prevent races between the lookup, 866 * an interrupt unbusy/free, and our protect call. 867 */ 868 crit_enter(); 869 for (idx = start; idx < end; idx++) { 870 p = vm_page_lookup(object, idx); 871 if (p == NULL) 872 continue; 873 vm_page_protect(p, VM_PROT_READ); 874 } 875 crit_exit(); 876 } 877 878 /* 879 * vm_object_pmap_remove: 880 * 881 * Removes all physical pages in the specified 882 * object range from all physical maps. 883 * 884 * The object must *not* be locked. 885 */ 886 void 887 vm_object_pmap_remove(vm_object_t object, vm_pindex_t start, vm_pindex_t end) 888 { 889 vm_page_t p; 890 891 if (object == NULL) 892 return; 893 894 /* 895 * spl protection is required because an interrupt can unbusy/free 896 * a page. 897 */ 898 crit_enter(); 899 for (p = TAILQ_FIRST(&object->memq); 900 p != NULL; 901 p = TAILQ_NEXT(p, listq) 902 ) { 903 if (p->pindex >= start && p->pindex < end) 904 vm_page_protect(p, VM_PROT_NONE); 905 } 906 crit_exit(); 907 if ((start == 0) && (object->size == end)) 908 vm_object_clear_flag(object, OBJ_WRITEABLE); 909 } 910 911 /* 912 * vm_object_madvise: 913 * 914 * Implements the madvise function at the object/page level. 915 * 916 * MADV_WILLNEED (any object) 917 * 918 * Activate the specified pages if they are resident. 919 * 920 * MADV_DONTNEED (any object) 921 * 922 * Deactivate the specified pages if they are resident. 923 * 924 * MADV_FREE (OBJT_DEFAULT/OBJT_SWAP objects, 925 * OBJ_ONEMAPPING only) 926 * 927 * Deactivate and clean the specified pages if they are 928 * resident. This permits the process to reuse the pages 929 * without faulting or the kernel to reclaim the pages 930 * without I/O. 931 */ 932 void 933 vm_object_madvise(vm_object_t object, vm_pindex_t pindex, int count, int advise) 934 { 935 vm_pindex_t end, tpindex; 936 vm_object_t tobject; 937 vm_page_t m; 938 939 if (object == NULL) 940 return; 941 942 end = pindex + count; 943 944 /* 945 * Locate and adjust resident pages 946 */ 947 948 for (; pindex < end; pindex += 1) { 949 relookup: 950 tobject = object; 951 tpindex = pindex; 952 shadowlookup: 953 /* 954 * MADV_FREE only operates on OBJT_DEFAULT or OBJT_SWAP pages 955 * and those pages must be OBJ_ONEMAPPING. 956 */ 957 if (advise == MADV_FREE) { 958 if ((tobject->type != OBJT_DEFAULT && 959 tobject->type != OBJT_SWAP) || 960 (tobject->flags & OBJ_ONEMAPPING) == 0) { 961 continue; 962 } 963 } 964 965 /* 966 * spl protection is required to avoid a race between the 967 * lookup, an interrupt unbusy/free, and our busy check. 968 */ 969 970 crit_enter(); 971 m = vm_page_lookup(tobject, tpindex); 972 973 if (m == NULL) { 974 /* 975 * There may be swap even if there is no backing page 976 */ 977 if (advise == MADV_FREE && tobject->type == OBJT_SWAP) 978 swap_pager_freespace(tobject, tpindex, 1); 979 980 /* 981 * next object 982 */ 983 crit_exit(); 984 if (tobject->backing_object == NULL) 985 continue; 986 tpindex += OFF_TO_IDX(tobject->backing_object_offset); 987 tobject = tobject->backing_object; 988 goto shadowlookup; 989 } 990 991 /* 992 * If the page is busy or not in a normal active state, 993 * we skip it. If the page is not managed there are no 994 * page queues to mess with. Things can break if we mess 995 * with pages in any of the below states. 996 */ 997 if ( 998 m->hold_count || 999 m->wire_count || 1000 (m->flags & PG_UNMANAGED) || 1001 m->valid != VM_PAGE_BITS_ALL 1002 ) { 1003 crit_exit(); 1004 continue; 1005 } 1006 1007 if (vm_page_sleep_busy(m, TRUE, "madvpo")) { 1008 crit_exit(); 1009 goto relookup; 1010 } 1011 crit_exit(); 1012 1013 /* 1014 * Theoretically once a page is known not to be busy, an 1015 * interrupt cannot come along and rip it out from under us. 1016 */ 1017 1018 if (advise == MADV_WILLNEED) { 1019 vm_page_activate(m); 1020 } else if (advise == MADV_DONTNEED) { 1021 vm_page_dontneed(m); 1022 } else if (advise == MADV_FREE) { 1023 /* 1024 * Mark the page clean. This will allow the page 1025 * to be freed up by the system. However, such pages 1026 * are often reused quickly by malloc()/free() 1027 * so we do not do anything that would cause 1028 * a page fault if we can help it. 1029 * 1030 * Specifically, we do not try to actually free 1031 * the page now nor do we try to put it in the 1032 * cache (which would cause a page fault on reuse). 1033 * 1034 * But we do make the page is freeable as we 1035 * can without actually taking the step of unmapping 1036 * it. 1037 */ 1038 pmap_clear_modify(m); 1039 m->dirty = 0; 1040 m->act_count = 0; 1041 vm_page_dontneed(m); 1042 if (tobject->type == OBJT_SWAP) 1043 swap_pager_freespace(tobject, tpindex, 1); 1044 } 1045 } 1046 } 1047 1048 /* 1049 * vm_object_shadow: 1050 * 1051 * Create a new object which is backed by the 1052 * specified existing object range. The source 1053 * object reference is deallocated. 1054 * 1055 * The new object and offset into that object 1056 * are returned in the source parameters. 1057 */ 1058 1059 void 1060 vm_object_shadow(vm_object_t *object, /* IN/OUT */ 1061 vm_ooffset_t *offset, /* IN/OUT */ 1062 vm_size_t length) 1063 { 1064 vm_object_t source; 1065 vm_object_t result; 1066 1067 source = *object; 1068 1069 /* 1070 * Don't create the new object if the old object isn't shared. 1071 */ 1072 1073 if (source != NULL && 1074 source->ref_count == 1 && 1075 source->handle == NULL && 1076 (source->type == OBJT_DEFAULT || 1077 source->type == OBJT_SWAP)) 1078 return; 1079 1080 /* 1081 * Allocate a new object with the given length 1082 */ 1083 1084 if ((result = vm_object_allocate(OBJT_DEFAULT, length)) == NULL) 1085 panic("vm_object_shadow: no object for shadowing"); 1086 1087 /* 1088 * The new object shadows the source object, adding a reference to it. 1089 * Our caller changes his reference to point to the new object, 1090 * removing a reference to the source object. Net result: no change 1091 * of reference count. 1092 * 1093 * Try to optimize the result object's page color when shadowing 1094 * in order to maintain page coloring consistency in the combined 1095 * shadowed object. 1096 */ 1097 result->backing_object = source; 1098 if (source) { 1099 LIST_INSERT_HEAD(&source->shadow_head, result, shadow_list); 1100 source->shadow_count++; 1101 source->generation++; 1102 result->pg_color = (source->pg_color + OFF_TO_IDX(*offset)) & PQ_L2_MASK; 1103 } 1104 1105 /* 1106 * Store the offset into the source object, and fix up the offset into 1107 * the new object. 1108 */ 1109 1110 result->backing_object_offset = *offset; 1111 1112 /* 1113 * Return the new things 1114 */ 1115 1116 *offset = 0; 1117 *object = result; 1118 } 1119 1120 #define OBSC_TEST_ALL_SHADOWED 0x0001 1121 #define OBSC_COLLAPSE_NOWAIT 0x0002 1122 #define OBSC_COLLAPSE_WAIT 0x0004 1123 1124 static __inline int 1125 vm_object_backing_scan(vm_object_t object, int op) 1126 { 1127 int r = 1; 1128 vm_page_t p; 1129 vm_object_t backing_object; 1130 vm_pindex_t backing_offset_index; 1131 1132 /* 1133 * spl protection is required to avoid races between the memq/lookup, 1134 * an interrupt doing an unbusy/free, and our busy check. Amoung 1135 * other things. 1136 */ 1137 crit_enter(); 1138 1139 backing_object = object->backing_object; 1140 backing_offset_index = OFF_TO_IDX(object->backing_object_offset); 1141 1142 /* 1143 * Initial conditions 1144 */ 1145 1146 if (op & OBSC_TEST_ALL_SHADOWED) { 1147 /* 1148 * We do not want to have to test for the existence of 1149 * swap pages in the backing object. XXX but with the 1150 * new swapper this would be pretty easy to do. 1151 * 1152 * XXX what about anonymous MAP_SHARED memory that hasn't 1153 * been ZFOD faulted yet? If we do not test for this, the 1154 * shadow test may succeed! XXX 1155 */ 1156 if (backing_object->type != OBJT_DEFAULT) { 1157 crit_exit(); 1158 return(0); 1159 } 1160 } 1161 if (op & OBSC_COLLAPSE_WAIT) { 1162 KKASSERT((backing_object->flags & OBJ_DEAD) == 0); 1163 vm_object_set_flag(backing_object, OBJ_DEAD); 1164 } 1165 1166 /* 1167 * Our scan 1168 */ 1169 1170 p = TAILQ_FIRST(&backing_object->memq); 1171 while (p) { 1172 vm_page_t next = TAILQ_NEXT(p, listq); 1173 vm_pindex_t new_pindex = p->pindex - backing_offset_index; 1174 1175 if (op & OBSC_TEST_ALL_SHADOWED) { 1176 vm_page_t pp; 1177 1178 /* 1179 * Ignore pages outside the parent object's range 1180 * and outside the parent object's mapping of the 1181 * backing object. 1182 * 1183 * note that we do not busy the backing object's 1184 * page. 1185 */ 1186 1187 if ( 1188 p->pindex < backing_offset_index || 1189 new_pindex >= object->size 1190 ) { 1191 p = next; 1192 continue; 1193 } 1194 1195 /* 1196 * See if the parent has the page or if the parent's 1197 * object pager has the page. If the parent has the 1198 * page but the page is not valid, the parent's 1199 * object pager must have the page. 1200 * 1201 * If this fails, the parent does not completely shadow 1202 * the object and we might as well give up now. 1203 */ 1204 1205 pp = vm_page_lookup(object, new_pindex); 1206 if ( 1207 (pp == NULL || pp->valid == 0) && 1208 !vm_pager_has_page(object, new_pindex, NULL, NULL) 1209 ) { 1210 r = 0; 1211 break; 1212 } 1213 } 1214 1215 /* 1216 * Check for busy page 1217 */ 1218 1219 if (op & (OBSC_COLLAPSE_WAIT | OBSC_COLLAPSE_NOWAIT)) { 1220 vm_page_t pp; 1221 1222 if (op & OBSC_COLLAPSE_NOWAIT) { 1223 if ( 1224 (p->flags & PG_BUSY) || 1225 !p->valid || 1226 p->hold_count || 1227 p->wire_count || 1228 p->busy 1229 ) { 1230 p = next; 1231 continue; 1232 } 1233 } else if (op & OBSC_COLLAPSE_WAIT) { 1234 if (vm_page_sleep_busy(p, TRUE, "vmocol")) { 1235 /* 1236 * If we slept, anything could have 1237 * happened. Since the object is 1238 * marked dead, the backing offset 1239 * should not have changed so we 1240 * just restart our scan. 1241 */ 1242 p = TAILQ_FIRST(&backing_object->memq); 1243 continue; 1244 } 1245 } 1246 1247 /* 1248 * Busy the page 1249 */ 1250 vm_page_busy(p); 1251 1252 KASSERT( 1253 p->object == backing_object, 1254 ("vm_object_qcollapse(): object mismatch") 1255 ); 1256 1257 /* 1258 * Destroy any associated swap 1259 */ 1260 if (backing_object->type == OBJT_SWAP) { 1261 swap_pager_freespace( 1262 backing_object, 1263 p->pindex, 1264 1 1265 ); 1266 } 1267 1268 if ( 1269 p->pindex < backing_offset_index || 1270 new_pindex >= object->size 1271 ) { 1272 /* 1273 * Page is out of the parent object's range, we 1274 * can simply destroy it. 1275 */ 1276 vm_page_protect(p, VM_PROT_NONE); 1277 vm_page_free(p); 1278 p = next; 1279 continue; 1280 } 1281 1282 pp = vm_page_lookup(object, new_pindex); 1283 if ( 1284 pp != NULL || 1285 vm_pager_has_page(object, new_pindex, NULL, NULL) 1286 ) { 1287 /* 1288 * page already exists in parent OR swap exists 1289 * for this location in the parent. Destroy 1290 * the original page from the backing object. 1291 * 1292 * Leave the parent's page alone 1293 */ 1294 vm_page_protect(p, VM_PROT_NONE); 1295 vm_page_free(p); 1296 p = next; 1297 continue; 1298 } 1299 1300 /* 1301 * Page does not exist in parent, rename the 1302 * page from the backing object to the main object. 1303 * 1304 * If the page was mapped to a process, it can remain 1305 * mapped through the rename. 1306 */ 1307 if ((p->queue - p->pc) == PQ_CACHE) 1308 vm_page_deactivate(p); 1309 1310 vm_page_rename(p, object, new_pindex); 1311 /* page automatically made dirty by rename */ 1312 } 1313 p = next; 1314 } 1315 crit_exit(); 1316 return(r); 1317 } 1318 1319 1320 /* 1321 * this version of collapse allows the operation to occur earlier and 1322 * when paging_in_progress is true for an object... This is not a complete 1323 * operation, but should plug 99.9% of the rest of the leaks. 1324 */ 1325 static void 1326 vm_object_qcollapse(vm_object_t object) 1327 { 1328 vm_object_t backing_object = object->backing_object; 1329 1330 if (backing_object->ref_count != 1) 1331 return; 1332 1333 backing_object->ref_count += 2; 1334 1335 vm_object_backing_scan(object, OBSC_COLLAPSE_NOWAIT); 1336 1337 backing_object->ref_count -= 2; 1338 } 1339 1340 /* 1341 * vm_object_collapse: 1342 * 1343 * Collapse an object with the object backing it. 1344 * Pages in the backing object are moved into the 1345 * parent, and the backing object is deallocated. 1346 */ 1347 void 1348 vm_object_collapse(vm_object_t object) 1349 { 1350 while (TRUE) { 1351 vm_object_t backing_object; 1352 1353 /* 1354 * Verify that the conditions are right for collapse: 1355 * 1356 * The object exists and the backing object exists. 1357 */ 1358 if (object == NULL) 1359 break; 1360 1361 if ((backing_object = object->backing_object) == NULL) 1362 break; 1363 1364 /* 1365 * we check the backing object first, because it is most likely 1366 * not collapsable. 1367 */ 1368 if (backing_object->handle != NULL || 1369 (backing_object->type != OBJT_DEFAULT && 1370 backing_object->type != OBJT_SWAP) || 1371 (backing_object->flags & OBJ_DEAD) || 1372 object->handle != NULL || 1373 (object->type != OBJT_DEFAULT && 1374 object->type != OBJT_SWAP) || 1375 (object->flags & OBJ_DEAD)) { 1376 break; 1377 } 1378 1379 if ( 1380 object->paging_in_progress != 0 || 1381 backing_object->paging_in_progress != 0 1382 ) { 1383 vm_object_qcollapse(object); 1384 break; 1385 } 1386 1387 /* 1388 * We know that we can either collapse the backing object (if 1389 * the parent is the only reference to it) or (perhaps) have 1390 * the parent bypass the object if the parent happens to shadow 1391 * all the resident pages in the entire backing object. 1392 * 1393 * This is ignoring pager-backed pages such as swap pages. 1394 * vm_object_backing_scan fails the shadowing test in this 1395 * case. 1396 */ 1397 1398 if (backing_object->ref_count == 1) { 1399 /* 1400 * If there is exactly one reference to the backing 1401 * object, we can collapse it into the parent. 1402 */ 1403 vm_object_backing_scan(object, OBSC_COLLAPSE_WAIT); 1404 1405 /* 1406 * Move the pager from backing_object to object. 1407 */ 1408 1409 if (backing_object->type == OBJT_SWAP) { 1410 vm_object_pip_add(backing_object, 1); 1411 1412 /* 1413 * scrap the paging_offset junk and do a 1414 * discrete copy. This also removes major 1415 * assumptions about how the swap-pager 1416 * works from where it doesn't belong. The 1417 * new swapper is able to optimize the 1418 * destroy-source case. 1419 */ 1420 1421 vm_object_pip_add(object, 1); 1422 swap_pager_copy( 1423 backing_object, 1424 object, 1425 OFF_TO_IDX(object->backing_object_offset), TRUE); 1426 vm_object_pip_wakeup(object); 1427 1428 vm_object_pip_wakeup(backing_object); 1429 } 1430 /* 1431 * Object now shadows whatever backing_object did. 1432 * Note that the reference to 1433 * backing_object->backing_object moves from within 1434 * backing_object to within object. 1435 */ 1436 1437 LIST_REMOVE(object, shadow_list); 1438 object->backing_object->shadow_count--; 1439 object->backing_object->generation++; 1440 if (backing_object->backing_object) { 1441 LIST_REMOVE(backing_object, shadow_list); 1442 backing_object->backing_object->shadow_count--; 1443 backing_object->backing_object->generation++; 1444 } 1445 object->backing_object = backing_object->backing_object; 1446 if (object->backing_object) { 1447 LIST_INSERT_HEAD( 1448 &object->backing_object->shadow_head, 1449 object, 1450 shadow_list 1451 ); 1452 object->backing_object->shadow_count++; 1453 object->backing_object->generation++; 1454 } 1455 1456 object->backing_object_offset += 1457 backing_object->backing_object_offset; 1458 1459 /* 1460 * Discard backing_object. 1461 * 1462 * Since the backing object has no pages, no pager left, 1463 * and no object references within it, all that is 1464 * necessary is to dispose of it. 1465 */ 1466 1467 KASSERT(backing_object->ref_count == 1, ("backing_object %p was somehow re-referenced during collapse!", backing_object)); 1468 KASSERT(TAILQ_FIRST(&backing_object->memq) == NULL, ("backing_object %p somehow has left over pages during collapse!", backing_object)); 1469 crit_enter(); 1470 TAILQ_REMOVE( 1471 &vm_object_list, 1472 backing_object, 1473 object_list 1474 ); 1475 vm_object_count--; 1476 crit_exit(); 1477 1478 zfree(obj_zone, backing_object); 1479 1480 object_collapses++; 1481 } else { 1482 vm_object_t new_backing_object; 1483 1484 /* 1485 * If we do not entirely shadow the backing object, 1486 * there is nothing we can do so we give up. 1487 */ 1488 1489 if (vm_object_backing_scan(object, OBSC_TEST_ALL_SHADOWED) == 0) { 1490 break; 1491 } 1492 1493 /* 1494 * Make the parent shadow the next object in the 1495 * chain. Deallocating backing_object will not remove 1496 * it, since its reference count is at least 2. 1497 */ 1498 1499 LIST_REMOVE(object, shadow_list); 1500 backing_object->shadow_count--; 1501 backing_object->generation++; 1502 1503 new_backing_object = backing_object->backing_object; 1504 if ((object->backing_object = new_backing_object) != NULL) { 1505 vm_object_reference(new_backing_object); 1506 LIST_INSERT_HEAD( 1507 &new_backing_object->shadow_head, 1508 object, 1509 shadow_list 1510 ); 1511 new_backing_object->shadow_count++; 1512 new_backing_object->generation++; 1513 object->backing_object_offset += 1514 backing_object->backing_object_offset; 1515 } 1516 1517 /* 1518 * Drop the reference count on backing_object. Since 1519 * its ref_count was at least 2, it will not vanish; 1520 * so we don't need to call vm_object_deallocate, but 1521 * we do anyway. 1522 */ 1523 vm_object_deallocate(backing_object); 1524 object_bypasses++; 1525 } 1526 1527 /* 1528 * Try again with this object's new backing object. 1529 */ 1530 } 1531 } 1532 1533 /* 1534 * vm_object_page_remove: [internal] 1535 * 1536 * Removes all physical pages in the specified 1537 * object range from the object's list of pages. 1538 */ 1539 void 1540 vm_object_page_remove(vm_object_t object, vm_pindex_t start, vm_pindex_t end, 1541 boolean_t clean_only) 1542 { 1543 vm_page_t p, next; 1544 unsigned int size; 1545 int all; 1546 1547 if (object == NULL || object->resident_page_count == 0) 1548 return; 1549 1550 all = ((end == 0) && (start == 0)); 1551 1552 /* 1553 * Since physically-backed objects do not use managed pages, we can't 1554 * remove pages from the object (we must instead remove the page 1555 * references, and then destroy the object). 1556 */ 1557 KASSERT(object->type != OBJT_PHYS, 1558 ("attempt to remove pages from a physical object")); 1559 1560 /* 1561 * Indicating that the object is undergoing paging. 1562 * 1563 * spl protection is required to avoid a race between the memq scan, 1564 * an interrupt unbusy/free, and the busy check. 1565 */ 1566 vm_object_pip_add(object, 1); 1567 crit_enter(); 1568 again: 1569 size = end - start; 1570 if (all || size > object->resident_page_count / 4) { 1571 for (p = TAILQ_FIRST(&object->memq); p != NULL; p = next) { 1572 next = TAILQ_NEXT(p, listq); 1573 if (all || ((start <= p->pindex) && (p->pindex < end))) { 1574 if (p->wire_count != 0) { 1575 vm_page_protect(p, VM_PROT_NONE); 1576 if (!clean_only) 1577 p->valid = 0; 1578 continue; 1579 } 1580 1581 /* 1582 * The busy flags are only cleared at 1583 * interrupt -- minimize the spl transitions 1584 */ 1585 1586 if (vm_page_sleep_busy(p, TRUE, "vmopar")) 1587 goto again; 1588 1589 if (clean_only && p->valid) { 1590 vm_page_test_dirty(p); 1591 if (p->valid & p->dirty) 1592 continue; 1593 } 1594 1595 vm_page_busy(p); 1596 vm_page_protect(p, VM_PROT_NONE); 1597 vm_page_free(p); 1598 } 1599 } 1600 } else { 1601 while (size > 0) { 1602 if ((p = vm_page_lookup(object, start)) != 0) { 1603 if (p->wire_count != 0) { 1604 vm_page_protect(p, VM_PROT_NONE); 1605 if (!clean_only) 1606 p->valid = 0; 1607 start += 1; 1608 size -= 1; 1609 continue; 1610 } 1611 1612 /* 1613 * The busy flags are only cleared at 1614 * interrupt -- minimize the spl transitions 1615 */ 1616 if (vm_page_sleep_busy(p, TRUE, "vmopar")) 1617 goto again; 1618 1619 if (clean_only && p->valid) { 1620 vm_page_test_dirty(p); 1621 if (p->valid & p->dirty) { 1622 start += 1; 1623 size -= 1; 1624 continue; 1625 } 1626 } 1627 1628 vm_page_busy(p); 1629 vm_page_protect(p, VM_PROT_NONE); 1630 vm_page_free(p); 1631 } 1632 start += 1; 1633 size -= 1; 1634 } 1635 } 1636 crit_exit(); 1637 vm_object_pip_wakeup(object); 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 1762 if (entry == 0) { 1763 tmpe = map->header.next; 1764 entcount = map->nentries; 1765 while (entcount-- && (tmpe != &map->header)) { 1766 if( _vm_object_in_map(map, object, tmpe)) { 1767 return 1; 1768 } 1769 tmpe = tmpe->next; 1770 } 1771 } else if (entry->eflags & MAP_ENTRY_IS_SUB_MAP) { 1772 tmpm = entry->object.sub_map; 1773 tmpe = tmpm->header.next; 1774 entcount = tmpm->nentries; 1775 while (entcount-- && tmpe != &tmpm->header) { 1776 if( _vm_object_in_map(tmpm, object, tmpe)) { 1777 return 1; 1778 } 1779 tmpe = tmpe->next; 1780 } 1781 } else if ((obj = entry->object.vm_object) != NULL) { 1782 for(; obj; obj=obj->backing_object) 1783 if( obj == object) { 1784 return 1; 1785 } 1786 } 1787 return 0; 1788 } 1789 1790 static int vm_object_in_map_callback(struct proc *p, void *data); 1791 1792 struct vm_object_in_map_info { 1793 vm_object_t object; 1794 int rv; 1795 }; 1796 1797 static int 1798 vm_object_in_map(vm_object_t object) 1799 { 1800 struct vm_object_in_map_info info; 1801 1802 info.rv = 0; 1803 info.object = object; 1804 1805 allproc_scan(vm_object_in_map_callback, &info); 1806 if (info.rv) 1807 return 1; 1808 if( _vm_object_in_map( kernel_map, object, 0)) 1809 return 1; 1810 if( _vm_object_in_map( pager_map, object, 0)) 1811 return 1; 1812 if( _vm_object_in_map( buffer_map, object, 0)) 1813 return 1; 1814 return 0; 1815 } 1816 1817 static int 1818 vm_object_in_map_callback(struct proc *p, void *data) 1819 { 1820 struct vm_object_in_map_info *info = data; 1821 1822 if (p->p_vmspace) { 1823 if (_vm_object_in_map(&p->p_vmspace->vm_map, info->object, 0)) { 1824 info->rv = 1; 1825 return -1; 1826 } 1827 } 1828 return (0); 1829 } 1830 1831 DB_SHOW_COMMAND(vmochk, vm_object_check) 1832 { 1833 vm_object_t object; 1834 1835 /* 1836 * make sure that internal objs are in a map somewhere 1837 * and none have zero ref counts. 1838 */ 1839 for (object = TAILQ_FIRST(&vm_object_list); 1840 object != NULL; 1841 object = TAILQ_NEXT(object, object_list)) { 1842 if (object->handle == NULL && 1843 (object->type == OBJT_DEFAULT || object->type == OBJT_SWAP)) { 1844 if (object->ref_count == 0) { 1845 db_printf("vmochk: internal obj has zero ref count: %ld\n", 1846 (long)object->size); 1847 } 1848 if (!vm_object_in_map(object)) { 1849 db_printf( 1850 "vmochk: internal obj is not in a map: " 1851 "ref: %d, size: %lu: 0x%lx, backing_object: %p\n", 1852 object->ref_count, (u_long)object->size, 1853 (u_long)object->size, 1854 (void *)object->backing_object); 1855 } 1856 } 1857 } 1858 } 1859 1860 /* 1861 * vm_object_print: [ debug ] 1862 */ 1863 DB_SHOW_COMMAND(object, vm_object_print_static) 1864 { 1865 /* XXX convert args. */ 1866 vm_object_t object = (vm_object_t)addr; 1867 boolean_t full = have_addr; 1868 1869 vm_page_t p; 1870 1871 /* XXX count is an (unused) arg. Avoid shadowing it. */ 1872 #define count was_count 1873 1874 int count; 1875 1876 if (object == NULL) 1877 return; 1878 1879 db_iprintf( 1880 "Object %p: type=%d, size=0x%lx, res=%d, ref=%d, flags=0x%x\n", 1881 object, (int)object->type, (u_long)object->size, 1882 object->resident_page_count, object->ref_count, object->flags); 1883 /* 1884 * XXX no %qd in kernel. Truncate object->backing_object_offset. 1885 */ 1886 db_iprintf(" sref=%d, backing_object(%d)=(%p)+0x%lx\n", 1887 object->shadow_count, 1888 object->backing_object ? object->backing_object->ref_count : 0, 1889 object->backing_object, (long)object->backing_object_offset); 1890 1891 if (!full) 1892 return; 1893 1894 db_indent += 2; 1895 count = 0; 1896 for (p = TAILQ_FIRST(&object->memq); p != NULL; p = TAILQ_NEXT(p, listq)) { 1897 if (count == 0) 1898 db_iprintf("memory:="); 1899 else if (count == 6) { 1900 db_printf("\n"); 1901 db_iprintf(" ..."); 1902 count = 0; 1903 } else 1904 db_printf(","); 1905 count++; 1906 1907 db_printf("(off=0x%lx,page=0x%lx)", 1908 (u_long) p->pindex, (u_long) VM_PAGE_TO_PHYS(p)); 1909 } 1910 if (count != 0) 1911 db_printf("\n"); 1912 db_indent -= 2; 1913 } 1914 1915 /* XXX. */ 1916 #undef count 1917 1918 /* XXX need this non-static entry for calling from vm_map_print. */ 1919 void 1920 vm_object_print(/* db_expr_t */ long addr, 1921 boolean_t have_addr, 1922 /* db_expr_t */ long count, 1923 char *modif) 1924 { 1925 vm_object_print_static(addr, have_addr, count, modif); 1926 } 1927 1928 DB_SHOW_COMMAND(vmopag, vm_object_print_pages) 1929 { 1930 vm_object_t object; 1931 int nl = 0; 1932 int c; 1933 for (object = TAILQ_FIRST(&vm_object_list); 1934 object != NULL; 1935 object = TAILQ_NEXT(object, object_list)) { 1936 vm_pindex_t idx, fidx; 1937 vm_pindex_t osize; 1938 vm_paddr_t pa = -1, padiff; 1939 int rcount; 1940 vm_page_t m; 1941 1942 db_printf("new object: %p\n", (void *)object); 1943 if ( nl > 18) { 1944 c = cngetc(); 1945 if (c != ' ') 1946 return; 1947 nl = 0; 1948 } 1949 nl++; 1950 rcount = 0; 1951 fidx = 0; 1952 osize = object->size; 1953 if (osize > 128) 1954 osize = 128; 1955 for (idx = 0; idx < osize; idx++) { 1956 m = vm_page_lookup(object, idx); 1957 if (m == NULL) { 1958 if (rcount) { 1959 db_printf(" index(%ld)run(%d)pa(0x%lx)\n", 1960 (long)fidx, rcount, (long)pa); 1961 if ( nl > 18) { 1962 c = cngetc(); 1963 if (c != ' ') 1964 return; 1965 nl = 0; 1966 } 1967 nl++; 1968 rcount = 0; 1969 } 1970 continue; 1971 } 1972 1973 1974 if (rcount && 1975 (VM_PAGE_TO_PHYS(m) == pa + rcount * PAGE_SIZE)) { 1976 ++rcount; 1977 continue; 1978 } 1979 if (rcount) { 1980 padiff = pa + rcount * PAGE_SIZE - VM_PAGE_TO_PHYS(m); 1981 padiff >>= PAGE_SHIFT; 1982 padiff &= PQ_L2_MASK; 1983 if (padiff == 0) { 1984 pa = VM_PAGE_TO_PHYS(m) - rcount * PAGE_SIZE; 1985 ++rcount; 1986 continue; 1987 } 1988 db_printf(" index(%ld)run(%d)pa(0x%lx)", 1989 (long)fidx, rcount, (long)pa); 1990 db_printf("pd(%ld)\n", (long)padiff); 1991 if ( nl > 18) { 1992 c = cngetc(); 1993 if (c != ' ') 1994 return; 1995 nl = 0; 1996 } 1997 nl++; 1998 } 1999 fidx = idx; 2000 pa = VM_PAGE_TO_PHYS(m); 2001 rcount = 1; 2002 } 2003 if (rcount) { 2004 db_printf(" index(%ld)run(%d)pa(0x%lx)\n", 2005 (long)fidx, rcount, (long)pa); 2006 if ( nl > 18) { 2007 c = cngetc(); 2008 if (c != ' ') 2009 return; 2010 nl = 0; 2011 } 2012 nl++; 2013 } 2014 } 2015 } 2016 #endif /* DDB */ 2017