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 * $FreeBSD$ 65 */ 66 67 /* 68 * Virtual memory object module. 69 */ 70 71 #include <sys/param.h> 72 #include <sys/systm.h> 73 #include <sys/lock.h> 74 #include <sys/mman.h> 75 #include <sys/mount.h> 76 #include <sys/kernel.h> 77 #include <sys/sysctl.h> 78 #include <sys/mutex.h> 79 #include <sys/proc.h> /* for curproc, pageproc */ 80 #include <sys/socket.h> 81 #include <sys/vnode.h> 82 #include <sys/vmmeter.h> 83 #include <sys/sx.h> 84 85 #include <vm/vm.h> 86 #include <vm/vm_param.h> 87 #include <vm/pmap.h> 88 #include <vm/vm_map.h> 89 #include <vm/vm_object.h> 90 #include <vm/vm_page.h> 91 #include <vm/vm_pageout.h> 92 #include <vm/vm_pager.h> 93 #include <vm/vm_zone.h> 94 #include <vm/swap_pager.h> 95 #include <vm/vm_kern.h> 96 #include <vm/vm_extern.h> 97 98 #define EASY_SCAN_FACTOR 8 99 100 #define MSYNC_FLUSH_HARDSEQ 0x01 101 #define MSYNC_FLUSH_SOFTSEQ 0x02 102 103 /* 104 * msync / VM object flushing optimizations 105 */ 106 static int msync_flush_flags = MSYNC_FLUSH_HARDSEQ | MSYNC_FLUSH_SOFTSEQ; 107 SYSCTL_INT(_vm, OID_AUTO, msync_flush_flags, 108 CTLFLAG_RW, &msync_flush_flags, 0, ""); 109 110 static void vm_object_qcollapse(vm_object_t object); 111 static int vm_object_page_collect_flush(vm_object_t object, vm_page_t p, int curgeneration, int pagerflags); 112 113 /* 114 * Virtual memory objects maintain the actual data 115 * associated with allocated virtual memory. A given 116 * page of memory exists within exactly one object. 117 * 118 * An object is only deallocated when all "references" 119 * are given up. Only one "reference" to a given 120 * region of an object should be writeable. 121 * 122 * Associated with each object is a list of all resident 123 * memory pages belonging to that object; this list is 124 * maintained by the "vm_page" module, and locked by the object's 125 * lock. 126 * 127 * Each object also records a "pager" routine which is 128 * used to retrieve (and store) pages to the proper backing 129 * storage. In addition, objects may be backed by other 130 * objects from which they were virtual-copied. 131 * 132 * The only items within the object structure which are 133 * modified after time of creation are: 134 * reference count locked by object's lock 135 * pager routine locked by object's lock 136 * 137 */ 138 139 struct object_q vm_object_list; 140 static struct mtx vm_object_list_mtx; /* lock for object list and count */ 141 static long vm_object_count; /* count of all objects */ 142 vm_object_t kernel_object; 143 vm_object_t kmem_object; 144 static struct vm_object kernel_object_store; 145 static struct vm_object kmem_object_store; 146 extern int vm_pageout_page_count; 147 148 static long object_collapses; 149 static long object_bypasses; 150 static int next_index; 151 static vm_zone_t obj_zone; 152 static struct vm_zone obj_zone_store; 153 static int object_hash_rand; 154 #define VM_OBJECTS_INIT 256 155 static struct vm_object vm_objects_init[VM_OBJECTS_INIT]; 156 157 void 158 _vm_object_allocate(objtype_t type, vm_size_t size, vm_object_t object) 159 { 160 int incr; 161 162 GIANT_REQUIRED; 163 164 TAILQ_INIT(&object->memq); 165 TAILQ_INIT(&object->shadow_head); 166 167 object->type = type; 168 object->size = size; 169 object->ref_count = 1; 170 object->flags = 0; 171 if ((object->type == OBJT_DEFAULT) || (object->type == OBJT_SWAP)) 172 vm_object_set_flag(object, OBJ_ONEMAPPING); 173 object->paging_in_progress = 0; 174 object->resident_page_count = 0; 175 object->shadow_count = 0; 176 object->pg_color = next_index; 177 if ( size > (PQ_L2_SIZE / 3 + PQ_PRIME1)) 178 incr = PQ_L2_SIZE / 3 + PQ_PRIME1; 179 else 180 incr = size; 181 next_index = (next_index + incr) & PQ_L2_MASK; 182 object->handle = NULL; 183 object->backing_object = NULL; 184 object->backing_object_offset = (vm_ooffset_t) 0; 185 /* 186 * Try to generate a number that will spread objects out in the 187 * hash table. We 'wipe' new objects across the hash in 128 page 188 * increments plus 1 more to offset it a little more by the time 189 * it wraps around. 190 */ 191 object->hash_rand = object_hash_rand - 129; 192 193 object->generation++; 194 195 TAILQ_INSERT_TAIL(&vm_object_list, object, object_list); 196 vm_object_count++; 197 object_hash_rand = object->hash_rand; 198 } 199 200 /* 201 * vm_object_init: 202 * 203 * Initialize the VM objects module. 204 */ 205 void 206 vm_object_init(void) 207 { 208 GIANT_REQUIRED; 209 210 TAILQ_INIT(&vm_object_list); 211 mtx_init(&vm_object_list_mtx, "vm object_list", MTX_DEF); 212 vm_object_count = 0; 213 214 kernel_object = &kernel_object_store; 215 _vm_object_allocate(OBJT_DEFAULT, OFF_TO_IDX(VM_MAX_KERNEL_ADDRESS - VM_MIN_KERNEL_ADDRESS), 216 kernel_object); 217 218 kmem_object = &kmem_object_store; 219 _vm_object_allocate(OBJT_DEFAULT, OFF_TO_IDX(VM_MAX_KERNEL_ADDRESS - VM_MIN_KERNEL_ADDRESS), 220 kmem_object); 221 222 obj_zone = &obj_zone_store; 223 zbootinit(obj_zone, "VM OBJECT", sizeof (struct vm_object), 224 vm_objects_init, VM_OBJECTS_INIT); 225 } 226 227 void 228 vm_object_init2(void) 229 { 230 zinitna(obj_zone, NULL, NULL, 0, 0, 0, 1); 231 } 232 233 void 234 vm_object_set_flag(vm_object_t object, u_short bits) 235 { 236 GIANT_REQUIRED; 237 object->flags |= bits; 238 } 239 240 void 241 vm_object_clear_flag(vm_object_t object, u_short bits) 242 { 243 GIANT_REQUIRED; 244 object->flags &= ~bits; 245 } 246 247 void 248 vm_object_pip_add(vm_object_t object, short i) 249 { 250 GIANT_REQUIRED; 251 object->paging_in_progress += i; 252 } 253 254 void 255 vm_object_pip_subtract(vm_object_t object, short i) 256 { 257 GIANT_REQUIRED; 258 object->paging_in_progress -= i; 259 } 260 261 void 262 vm_object_pip_wakeup(vm_object_t object) 263 { 264 GIANT_REQUIRED; 265 object->paging_in_progress--; 266 if ((object->flags & OBJ_PIPWNT) && object->paging_in_progress == 0) { 267 vm_object_clear_flag(object, OBJ_PIPWNT); 268 wakeup(object); 269 } 270 } 271 272 void 273 vm_object_pip_wakeupn(vm_object_t object, short i) 274 { 275 GIANT_REQUIRED; 276 if (i) 277 object->paging_in_progress -= i; 278 if ((object->flags & OBJ_PIPWNT) && object->paging_in_progress == 0) { 279 vm_object_clear_flag(object, OBJ_PIPWNT); 280 wakeup(object); 281 } 282 } 283 284 void 285 vm_object_pip_sleep(vm_object_t object, char *waitid) 286 { 287 GIANT_REQUIRED; 288 if (object->paging_in_progress) { 289 int s = splvm(); 290 if (object->paging_in_progress) { 291 vm_object_set_flag(object, OBJ_PIPWNT); 292 tsleep(object, PVM, waitid, 0); 293 } 294 splx(s); 295 } 296 } 297 298 void 299 vm_object_pip_wait(vm_object_t object, char *waitid) 300 { 301 GIANT_REQUIRED; 302 while (object->paging_in_progress) 303 vm_object_pip_sleep(object, waitid); 304 } 305 306 /* 307 * vm_object_allocate: 308 * 309 * Returns a new object with the given size. 310 */ 311 312 vm_object_t 313 vm_object_allocate(objtype_t type, vm_size_t size) 314 { 315 vm_object_t result; 316 317 GIANT_REQUIRED; 318 319 result = (vm_object_t) zalloc(obj_zone); 320 _vm_object_allocate(type, size, result); 321 322 return (result); 323 } 324 325 326 /* 327 * vm_object_reference: 328 * 329 * Gets another reference to the given object. 330 */ 331 void 332 vm_object_reference(vm_object_t object) 333 { 334 GIANT_REQUIRED; 335 336 if (object == NULL) 337 return; 338 339 #if 0 340 /* object can be re-referenced during final cleaning */ 341 KASSERT(!(object->flags & OBJ_DEAD), 342 ("vm_object_reference: attempting to reference dead obj")); 343 #endif 344 345 object->ref_count++; 346 if (object->type == OBJT_VNODE) { 347 while (vget((struct vnode *) object->handle, LK_RETRY|LK_NOOBJ, curthread)) { 348 printf("vm_object_reference: delay in getting object\n"); 349 } 350 } 351 } 352 353 /* 354 * handle deallocating a object of type OBJT_VNODE 355 */ 356 void 357 vm_object_vndeallocate(vm_object_t object) 358 { 359 struct vnode *vp = (struct vnode *) object->handle; 360 361 GIANT_REQUIRED; 362 KASSERT(object->type == OBJT_VNODE, 363 ("vm_object_vndeallocate: not a vnode object")); 364 KASSERT(vp != NULL, ("vm_object_vndeallocate: missing vp")); 365 #ifdef INVARIANTS 366 if (object->ref_count == 0) { 367 vprint("vm_object_vndeallocate", vp); 368 panic("vm_object_vndeallocate: bad object reference count"); 369 } 370 #endif 371 372 object->ref_count--; 373 if (object->ref_count == 0) { 374 vp->v_flag &= ~VTEXT; 375 vm_object_clear_flag(object, OBJ_OPT); 376 } 377 /* 378 * vrele may need a vop lock 379 */ 380 vrele(vp); 381 } 382 383 /* 384 * vm_object_deallocate: 385 * 386 * Release a reference to the specified object, 387 * gained either through a vm_object_allocate 388 * or a vm_object_reference call. When all references 389 * are gone, storage associated with this object 390 * may be relinquished. 391 * 392 * No object may be locked. 393 */ 394 void 395 vm_object_deallocate(vm_object_t object) 396 { 397 vm_object_t temp; 398 399 GIANT_REQUIRED; 400 401 while (object != NULL) { 402 403 if (object->type == OBJT_VNODE) { 404 vm_object_vndeallocate(object); 405 return; 406 } 407 408 KASSERT(object->ref_count != 0, 409 ("vm_object_deallocate: object deallocated too many times: %d", object->type)); 410 411 /* 412 * If the reference count goes to 0 we start calling 413 * vm_object_terminate() on the object chain. 414 * A ref count of 1 may be a special case depending on the 415 * shadow count being 0 or 1. 416 */ 417 object->ref_count--; 418 if (object->ref_count > 1) { 419 return; 420 } else if (object->ref_count == 1) { 421 if (object->shadow_count == 0) { 422 vm_object_set_flag(object, OBJ_ONEMAPPING); 423 } else if ((object->shadow_count == 1) && 424 (object->handle == NULL) && 425 (object->type == OBJT_DEFAULT || 426 object->type == OBJT_SWAP)) { 427 vm_object_t robject; 428 429 robject = TAILQ_FIRST(&object->shadow_head); 430 KASSERT(robject != NULL, 431 ("vm_object_deallocate: ref_count: %d, shadow_count: %d", 432 object->ref_count, 433 object->shadow_count)); 434 if ((robject->handle == NULL) && 435 (robject->type == OBJT_DEFAULT || 436 robject->type == OBJT_SWAP)) { 437 438 robject->ref_count++; 439 440 while ( 441 robject->paging_in_progress || 442 object->paging_in_progress 443 ) { 444 vm_object_pip_sleep(robject, "objde1"); 445 vm_object_pip_sleep(object, "objde2"); 446 } 447 448 if (robject->ref_count == 1) { 449 robject->ref_count--; 450 object = robject; 451 goto doterm; 452 } 453 454 object = robject; 455 vm_object_collapse(object); 456 continue; 457 } 458 } 459 460 return; 461 462 } 463 464 doterm: 465 466 temp = object->backing_object; 467 if (temp) { 468 TAILQ_REMOVE(&temp->shadow_head, object, shadow_list); 469 temp->shadow_count--; 470 if (temp->ref_count == 0) 471 vm_object_clear_flag(temp, OBJ_OPT); 472 temp->generation++; 473 object->backing_object = NULL; 474 } 475 /* 476 * Don't double-terminate, we could be in a termination 477 * recursion due to the terminate having to sync data 478 * to disk. 479 */ 480 if ((object->flags & OBJ_DEAD) == 0) 481 vm_object_terminate(object); 482 object = temp; 483 } 484 } 485 486 /* 487 * vm_object_terminate actually destroys the specified object, freeing 488 * up all previously used resources. 489 * 490 * The object must be locked. 491 * This routine may block. 492 */ 493 void 494 vm_object_terminate(vm_object_t object) 495 { 496 vm_page_t p; 497 int s; 498 499 GIANT_REQUIRED; 500 501 /* 502 * Make sure no one uses us. 503 */ 504 vm_object_set_flag(object, OBJ_DEAD); 505 506 /* 507 * wait for the pageout daemon to be done with the object 508 */ 509 vm_object_pip_wait(object, "objtrm"); 510 511 KASSERT(!object->paging_in_progress, 512 ("vm_object_terminate: pageout in progress")); 513 514 /* 515 * Clean and free the pages, as appropriate. All references to the 516 * object are gone, so we don't need to lock it. 517 */ 518 if (object->type == OBJT_VNODE) { 519 struct vnode *vp; 520 521 /* 522 * Freeze optimized copies. 523 */ 524 vm_freeze_copyopts(object, 0, object->size); 525 526 /* 527 * Clean pages and flush buffers. 528 */ 529 vm_object_page_clean(object, 0, 0, OBJPC_SYNC); 530 531 vp = (struct vnode *) object->handle; 532 vinvalbuf(vp, V_SAVE, NOCRED, NULL, 0, 0); 533 } 534 535 KASSERT(object->ref_count == 0, 536 ("vm_object_terminate: object with references, ref_count=%d", 537 object->ref_count)); 538 539 /* 540 * Now free any remaining pages. For internal objects, this also 541 * removes them from paging queues. Don't free wired pages, just 542 * remove them from the object. 543 */ 544 s = splvm(); 545 while ((p = TAILQ_FIRST(&object->memq)) != NULL) { 546 KASSERT(!p->busy && (p->flags & PG_BUSY) == 0, 547 ("vm_object_terminate: freeing busy page %p " 548 "p->busy = %d, p->flags %x\n", p, p->busy, p->flags)); 549 if (p->wire_count == 0) { 550 vm_page_busy(p); 551 vm_page_free(p); 552 cnt.v_pfree++; 553 } else { 554 vm_page_busy(p); 555 vm_page_remove(p); 556 } 557 } 558 splx(s); 559 560 /* 561 * Let the pager know object is dead. 562 */ 563 vm_pager_deallocate(object); 564 565 /* 566 * Remove the object from the global object list. 567 */ 568 mtx_lock(&vm_object_list_mtx); 569 TAILQ_REMOVE(&vm_object_list, object, object_list); 570 mtx_unlock(&vm_object_list_mtx); 571 572 wakeup(object); 573 574 /* 575 * Free the space for the object. 576 */ 577 zfree(obj_zone, object); 578 } 579 580 /* 581 * vm_object_page_clean 582 * 583 * Clean all dirty pages in the specified range of object. Leaves page 584 * on whatever queue it is currently on. If NOSYNC is set then do not 585 * write out pages with PG_NOSYNC set (originally comes from MAP_NOSYNC), 586 * leaving the object dirty. 587 * 588 * Odd semantics: if start == end, we clean everything. 589 * 590 * The object must be locked. 591 */ 592 593 void 594 vm_object_page_clean(vm_object_t object, vm_pindex_t start, vm_pindex_t end, int flags) 595 { 596 vm_page_t p, np; 597 vm_offset_t tstart, tend; 598 vm_pindex_t pi; 599 struct vnode *vp; 600 int clearobjflags; 601 int pagerflags; 602 int curgeneration; 603 604 GIANT_REQUIRED; 605 606 if (object->type != OBJT_VNODE || 607 (object->flags & OBJ_MIGHTBEDIRTY) == 0) 608 return; 609 610 pagerflags = (flags & (OBJPC_SYNC | OBJPC_INVAL)) ? VM_PAGER_PUT_SYNC : 0; 611 pagerflags |= (flags & OBJPC_INVAL) ? VM_PAGER_PUT_INVAL : 0; 612 613 vp = object->handle; 614 615 vm_object_set_flag(object, OBJ_CLEANING); 616 617 tstart = start; 618 if (end == 0) { 619 tend = object->size; 620 } else { 621 tend = end; 622 } 623 624 /* 625 * If the caller is smart and only msync()s a range he knows is 626 * dirty, we may be able to avoid an object scan. This results in 627 * a phenominal improvement in performance. We cannot do this 628 * as a matter of course because the object may be huge - e.g. 629 * the size might be in the gigabytes or terrabytes. 630 */ 631 if (msync_flush_flags & MSYNC_FLUSH_HARDSEQ) { 632 vm_offset_t tscan; 633 int scanlimit; 634 int scanreset; 635 636 scanreset = object->resident_page_count / EASY_SCAN_FACTOR; 637 if (scanreset < 16) 638 scanreset = 16; 639 640 scanlimit = scanreset; 641 tscan = tstart; 642 while (tscan < tend) { 643 curgeneration = object->generation; 644 p = vm_page_lookup(object, tscan); 645 if (p == NULL || p->valid == 0 || 646 (p->queue - p->pc) == PQ_CACHE) { 647 if (--scanlimit == 0) 648 break; 649 ++tscan; 650 continue; 651 } 652 vm_page_test_dirty(p); 653 if ((p->dirty & p->valid) == 0) { 654 if (--scanlimit == 0) 655 break; 656 ++tscan; 657 continue; 658 } 659 /* 660 * If we have been asked to skip nosync pages and 661 * this is a nosync page, we can't continue. 662 */ 663 if ((flags & OBJPC_NOSYNC) && (p->flags & PG_NOSYNC)) { 664 if (--scanlimit == 0) 665 break; 666 ++tscan; 667 continue; 668 } 669 scanlimit = scanreset; 670 671 /* 672 * This returns 0 if it was unable to busy the first 673 * page (i.e. had to sleep). 674 */ 675 tscan += vm_object_page_collect_flush(object, p, curgeneration, pagerflags); 676 } 677 678 /* 679 * If everything was dirty and we flushed it successfully, 680 * and the requested range is not the entire object, we 681 * don't have to mess with CLEANCHK or MIGHTBEDIRTY and can 682 * return immediately. 683 */ 684 if (tscan >= tend && (tstart || tend < object->size)) { 685 vm_object_clear_flag(object, OBJ_CLEANING); 686 return; 687 } 688 } 689 690 /* 691 * Generally set CLEANCHK interlock and make the page read-only so 692 * we can then clear the object flags. 693 * 694 * However, if this is a nosync mmap then the object is likely to 695 * stay dirty so do not mess with the page and do not clear the 696 * object flags. 697 */ 698 699 clearobjflags = 1; 700 701 TAILQ_FOREACH(p, &object->memq, listq) { 702 vm_page_flag_set(p, PG_CLEANCHK); 703 if ((flags & OBJPC_NOSYNC) && (p->flags & PG_NOSYNC)) 704 clearobjflags = 0; 705 else 706 vm_page_protect(p, VM_PROT_READ); 707 } 708 709 if (clearobjflags && (tstart == 0) && (tend == object->size)) { 710 struct vnode *vp; 711 712 vm_object_clear_flag(object, OBJ_WRITEABLE|OBJ_MIGHTBEDIRTY); 713 if (object->type == OBJT_VNODE && 714 (vp = (struct vnode *)object->handle) != NULL) { 715 if (vp->v_flag & VOBJDIRTY) { 716 mtx_lock(&vp->v_interlock); 717 vp->v_flag &= ~VOBJDIRTY; 718 mtx_unlock(&vp->v_interlock); 719 } 720 } 721 } 722 723 rescan: 724 curgeneration = object->generation; 725 726 for (p = TAILQ_FIRST(&object->memq); p; p = np) { 727 int n; 728 729 np = TAILQ_NEXT(p, listq); 730 731 again: 732 pi = p->pindex; 733 if (((p->flags & PG_CLEANCHK) == 0) || 734 (pi < tstart) || (pi >= tend) || 735 (p->valid == 0) || 736 ((p->queue - p->pc) == PQ_CACHE)) { 737 vm_page_flag_clear(p, PG_CLEANCHK); 738 continue; 739 } 740 741 vm_page_test_dirty(p); 742 if ((p->dirty & p->valid) == 0) { 743 vm_page_flag_clear(p, PG_CLEANCHK); 744 continue; 745 } 746 747 /* 748 * If we have been asked to skip nosync pages and this is a 749 * nosync page, skip it. Note that the object flags were 750 * not cleared in this case so we do not have to set them. 751 */ 752 if ((flags & OBJPC_NOSYNC) && (p->flags & PG_NOSYNC)) { 753 vm_page_flag_clear(p, PG_CLEANCHK); 754 continue; 755 } 756 757 n = vm_object_page_collect_flush(object, p, 758 curgeneration, pagerflags); 759 if (n == 0) 760 goto rescan; 761 762 if (object->generation != curgeneration) 763 goto rescan; 764 765 /* 766 * Try to optimize the next page. If we can't we pick up 767 * our (random) scan where we left off. 768 */ 769 if (msync_flush_flags & MSYNC_FLUSH_SOFTSEQ) { 770 if ((p = vm_page_lookup(object, pi + n)) != NULL) 771 goto again; 772 } 773 } 774 775 #if 0 776 VOP_FSYNC(vp, NULL, (pagerflags & VM_PAGER_PUT_SYNC)?MNT_WAIT:0, curproc); 777 #endif 778 779 vm_object_clear_flag(object, OBJ_CLEANING); 780 return; 781 } 782 783 static int 784 vm_object_page_collect_flush(vm_object_t object, vm_page_t p, int curgeneration, int pagerflags) 785 { 786 int runlen; 787 int s; 788 int maxf; 789 int chkb; 790 int maxb; 791 int i; 792 vm_pindex_t pi; 793 vm_page_t maf[vm_pageout_page_count]; 794 vm_page_t mab[vm_pageout_page_count]; 795 vm_page_t ma[vm_pageout_page_count]; 796 797 s = splvm(); 798 pi = p->pindex; 799 while (vm_page_sleep_busy(p, TRUE, "vpcwai")) { 800 if (object->generation != curgeneration) { 801 splx(s); 802 return(0); 803 } 804 } 805 806 maxf = 0; 807 for(i = 1; i < vm_pageout_page_count; i++) { 808 vm_page_t tp; 809 810 if ((tp = vm_page_lookup(object, pi + i)) != NULL) { 811 if ((tp->flags & PG_BUSY) || 812 (tp->flags & PG_CLEANCHK) == 0 || 813 (tp->busy != 0)) 814 break; 815 if((tp->queue - tp->pc) == PQ_CACHE) { 816 vm_page_flag_clear(tp, PG_CLEANCHK); 817 break; 818 } 819 vm_page_test_dirty(tp); 820 if ((tp->dirty & tp->valid) == 0) { 821 vm_page_flag_clear(tp, PG_CLEANCHK); 822 break; 823 } 824 maf[ i - 1 ] = tp; 825 maxf++; 826 continue; 827 } 828 break; 829 } 830 831 maxb = 0; 832 chkb = vm_pageout_page_count - maxf; 833 if (chkb) { 834 for(i = 1; i < chkb;i++) { 835 vm_page_t tp; 836 837 if ((tp = vm_page_lookup(object, pi - i)) != NULL) { 838 if ((tp->flags & PG_BUSY) || 839 (tp->flags & PG_CLEANCHK) == 0 || 840 (tp->busy != 0)) 841 break; 842 if((tp->queue - tp->pc) == PQ_CACHE) { 843 vm_page_flag_clear(tp, PG_CLEANCHK); 844 break; 845 } 846 vm_page_test_dirty(tp); 847 if ((tp->dirty & tp->valid) == 0) { 848 vm_page_flag_clear(tp, PG_CLEANCHK); 849 break; 850 } 851 mab[ i - 1 ] = tp; 852 maxb++; 853 continue; 854 } 855 break; 856 } 857 } 858 859 for(i = 0; i < maxb; i++) { 860 int index = (maxb - i) - 1; 861 ma[index] = mab[i]; 862 vm_page_flag_clear(ma[index], PG_CLEANCHK); 863 } 864 vm_page_flag_clear(p, PG_CLEANCHK); 865 ma[maxb] = p; 866 for(i = 0; i < maxf; i++) { 867 int index = (maxb + i) + 1; 868 ma[index] = maf[i]; 869 vm_page_flag_clear(ma[index], PG_CLEANCHK); 870 } 871 runlen = maxb + maxf + 1; 872 873 splx(s); 874 vm_pageout_flush(ma, runlen, pagerflags); 875 for (i = 0; i < runlen; i++) { 876 if (ma[i]->valid & ma[i]->dirty) { 877 vm_page_protect(ma[i], VM_PROT_READ); 878 vm_page_flag_set(ma[i], PG_CLEANCHK); 879 880 /* 881 * maxf will end up being the actual number of pages 882 * we wrote out contiguously, non-inclusive of the 883 * first page. We do not count look-behind pages. 884 */ 885 if (i >= maxb + 1 && (maxf > i - maxb - 1)) 886 maxf = i - maxb - 1; 887 } 888 } 889 return(maxf + 1); 890 } 891 892 /* 893 * Same as vm_object_pmap_copy, except range checking really 894 * works, and is meant for small sections of an object. 895 * 896 * This code protects resident pages by making them read-only 897 * and is typically called on a fork or split when a page 898 * is converted to copy-on-write. 899 * 900 * NOTE: If the page is already at VM_PROT_NONE, calling 901 * vm_page_protect will have no effect. 902 */ 903 904 void 905 vm_object_pmap_copy_1(vm_object_t object, vm_pindex_t start, vm_pindex_t end) 906 { 907 vm_pindex_t idx; 908 vm_page_t p; 909 910 GIANT_REQUIRED; 911 912 if (object == NULL || (object->flags & OBJ_WRITEABLE) == 0) 913 return; 914 915 for (idx = start; idx < end; idx++) { 916 p = vm_page_lookup(object, idx); 917 if (p == NULL) 918 continue; 919 vm_page_protect(p, VM_PROT_READ); 920 } 921 } 922 923 /* 924 * vm_object_pmap_remove: 925 * 926 * Removes all physical pages in the specified 927 * object range from all physical maps. 928 * 929 * The object must *not* be locked. 930 */ 931 void 932 vm_object_pmap_remove(vm_object_t object, vm_pindex_t start, vm_pindex_t end) 933 { 934 vm_page_t p; 935 936 GIANT_REQUIRED; 937 if (object == NULL) 938 return; 939 TAILQ_FOREACH(p, &object->memq, listq) { 940 if (p->pindex >= start && p->pindex < end) 941 vm_page_protect(p, VM_PROT_NONE); 942 } 943 if ((start == 0) && (object->size == end)) 944 vm_object_clear_flag(object, OBJ_WRITEABLE); 945 } 946 947 /* 948 * vm_object_madvise: 949 * 950 * Implements the madvise function at the object/page level. 951 * 952 * MADV_WILLNEED (any object) 953 * 954 * Activate the specified pages if they are resident. 955 * 956 * MADV_DONTNEED (any object) 957 * 958 * Deactivate the specified pages if they are resident. 959 * 960 * MADV_FREE (OBJT_DEFAULT/OBJT_SWAP objects, 961 * OBJ_ONEMAPPING only) 962 * 963 * Deactivate and clean the specified pages if they are 964 * resident. This permits the process to reuse the pages 965 * without faulting or the kernel to reclaim the pages 966 * without I/O. 967 */ 968 void 969 vm_object_madvise(vm_object_t object, vm_pindex_t pindex, int count, int advise) 970 { 971 vm_pindex_t end, tpindex; 972 vm_object_t tobject; 973 vm_page_t m; 974 975 GIANT_REQUIRED; 976 if (object == NULL) 977 return; 978 979 end = pindex + count; 980 981 /* 982 * Locate and adjust resident pages 983 */ 984 985 for (; pindex < end; pindex += 1) { 986 relookup: 987 tobject = object; 988 tpindex = pindex; 989 shadowlookup: 990 /* 991 * MADV_FREE only operates on OBJT_DEFAULT or OBJT_SWAP pages 992 * and those pages must be OBJ_ONEMAPPING. 993 */ 994 if (advise == MADV_FREE) { 995 if ((tobject->type != OBJT_DEFAULT && 996 tobject->type != OBJT_SWAP) || 997 (tobject->flags & OBJ_ONEMAPPING) == 0) { 998 continue; 999 } 1000 } 1001 1002 m = vm_page_lookup(tobject, tpindex); 1003 1004 if (m == NULL) { 1005 /* 1006 * There may be swap even if there is no backing page 1007 */ 1008 if (advise == MADV_FREE && tobject->type == OBJT_SWAP) 1009 swap_pager_freespace(tobject, tpindex, 1); 1010 1011 /* 1012 * next object 1013 */ 1014 tobject = tobject->backing_object; 1015 if (tobject == NULL) 1016 continue; 1017 tpindex += OFF_TO_IDX(tobject->backing_object_offset); 1018 goto shadowlookup; 1019 } 1020 1021 /* 1022 * If the page is busy or not in a normal active state, 1023 * we skip it. If the page is not managed there are no 1024 * page queues to mess with. Things can break if we mess 1025 * with pages in any of the below states. 1026 */ 1027 if ( 1028 m->hold_count || 1029 m->wire_count || 1030 (m->flags & PG_UNMANAGED) || 1031 m->valid != VM_PAGE_BITS_ALL 1032 ) { 1033 continue; 1034 } 1035 1036 if (vm_page_sleep_busy(m, TRUE, "madvpo")) 1037 goto relookup; 1038 1039 if (advise == MADV_WILLNEED) { 1040 vm_page_activate(m); 1041 } else if (advise == MADV_DONTNEED) { 1042 vm_page_dontneed(m); 1043 } else if (advise == MADV_FREE) { 1044 /* 1045 * Mark the page clean. This will allow the page 1046 * to be freed up by the system. However, such pages 1047 * are often reused quickly by malloc()/free() 1048 * so we do not do anything that would cause 1049 * a page fault if we can help it. 1050 * 1051 * Specifically, we do not try to actually free 1052 * the page now nor do we try to put it in the 1053 * cache (which would cause a page fault on reuse). 1054 * 1055 * But we do make the page is freeable as we 1056 * can without actually taking the step of unmapping 1057 * it. 1058 */ 1059 pmap_clear_modify(m); 1060 m->dirty = 0; 1061 m->act_count = 0; 1062 vm_page_dontneed(m); 1063 if (tobject->type == OBJT_SWAP) 1064 swap_pager_freespace(tobject, tpindex, 1); 1065 } 1066 } 1067 } 1068 1069 /* 1070 * vm_object_shadow: 1071 * 1072 * Create a new object which is backed by the 1073 * specified existing object range. The source 1074 * object reference is deallocated. 1075 * 1076 * The new object and offset into that object 1077 * are returned in the source parameters. 1078 */ 1079 1080 void 1081 vm_object_shadow( 1082 vm_object_t *object, /* IN/OUT */ 1083 vm_ooffset_t *offset, /* IN/OUT */ 1084 vm_size_t length) 1085 { 1086 vm_object_t source; 1087 vm_object_t result; 1088 1089 GIANT_REQUIRED; 1090 source = *object; 1091 1092 /* 1093 * Don't create the new object if the old object isn't shared. 1094 */ 1095 1096 if (source != NULL && 1097 source->ref_count == 1 && 1098 source->handle == NULL && 1099 (source->type == OBJT_DEFAULT || 1100 source->type == OBJT_SWAP)) 1101 return; 1102 1103 /* 1104 * Allocate a new object with the given length 1105 */ 1106 result = vm_object_allocate(OBJT_DEFAULT, length); 1107 KASSERT(result != NULL, ("vm_object_shadow: no object for shadowing")); 1108 1109 /* 1110 * The new object shadows the source object, adding a reference to it. 1111 * Our caller changes his reference to point to the new object, 1112 * removing a reference to the source object. Net result: no change 1113 * of reference count. 1114 * 1115 * Try to optimize the result object's page color when shadowing 1116 * in order to maintain page coloring consistency in the combined 1117 * shadowed object. 1118 */ 1119 result->backing_object = source; 1120 if (source) { 1121 TAILQ_INSERT_TAIL(&source->shadow_head, result, shadow_list); 1122 source->shadow_count++; 1123 source->generation++; 1124 result->pg_color = (source->pg_color + OFF_TO_IDX(*offset)) & PQ_L2_MASK; 1125 } 1126 1127 /* 1128 * Store the offset into the source object, and fix up the offset into 1129 * the new object. 1130 */ 1131 1132 result->backing_object_offset = *offset; 1133 1134 /* 1135 * Return the new things 1136 */ 1137 1138 *offset = 0; 1139 *object = result; 1140 } 1141 1142 #define OBSC_TEST_ALL_SHADOWED 0x0001 1143 #define OBSC_COLLAPSE_NOWAIT 0x0002 1144 #define OBSC_COLLAPSE_WAIT 0x0004 1145 1146 static __inline int 1147 vm_object_backing_scan(vm_object_t object, int op) 1148 { 1149 int s; 1150 int r = 1; 1151 vm_page_t p; 1152 vm_object_t backing_object; 1153 vm_pindex_t backing_offset_index; 1154 1155 s = splvm(); 1156 GIANT_REQUIRED; 1157 1158 backing_object = object->backing_object; 1159 backing_offset_index = OFF_TO_IDX(object->backing_object_offset); 1160 1161 /* 1162 * Initial conditions 1163 */ 1164 1165 if (op & OBSC_TEST_ALL_SHADOWED) { 1166 /* 1167 * We do not want to have to test for the existence of 1168 * swap pages in the backing object. XXX but with the 1169 * new swapper this would be pretty easy to do. 1170 * 1171 * XXX what about anonymous MAP_SHARED memory that hasn't 1172 * been ZFOD faulted yet? If we do not test for this, the 1173 * shadow test may succeed! XXX 1174 */ 1175 if (backing_object->type != OBJT_DEFAULT) { 1176 splx(s); 1177 return(0); 1178 } 1179 } 1180 if (op & OBSC_COLLAPSE_WAIT) { 1181 vm_object_set_flag(backing_object, OBJ_DEAD); 1182 } 1183 1184 /* 1185 * Our scan 1186 */ 1187 1188 p = TAILQ_FIRST(&backing_object->memq); 1189 while (p) { 1190 vm_page_t next = TAILQ_NEXT(p, listq); 1191 vm_pindex_t new_pindex = p->pindex - backing_offset_index; 1192 1193 if (op & OBSC_TEST_ALL_SHADOWED) { 1194 vm_page_t pp; 1195 1196 /* 1197 * Ignore pages outside the parent object's range 1198 * and outside the parent object's mapping of the 1199 * backing object. 1200 * 1201 * note that we do not busy the backing object's 1202 * page. 1203 */ 1204 1205 if ( 1206 p->pindex < backing_offset_index || 1207 new_pindex >= object->size 1208 ) { 1209 p = next; 1210 continue; 1211 } 1212 1213 /* 1214 * See if the parent has the page or if the parent's 1215 * object pager has the page. If the parent has the 1216 * page but the page is not valid, the parent's 1217 * object pager must have the page. 1218 * 1219 * If this fails, the parent does not completely shadow 1220 * the object and we might as well give up now. 1221 */ 1222 1223 pp = vm_page_lookup(object, new_pindex); 1224 if ( 1225 (pp == NULL || pp->valid == 0) && 1226 !vm_pager_has_page(object, new_pindex, NULL, NULL) 1227 ) { 1228 r = 0; 1229 break; 1230 } 1231 } 1232 1233 /* 1234 * Check for busy page 1235 */ 1236 1237 if (op & (OBSC_COLLAPSE_WAIT | OBSC_COLLAPSE_NOWAIT)) { 1238 vm_page_t pp; 1239 1240 if (op & OBSC_COLLAPSE_NOWAIT) { 1241 if ( 1242 (p->flags & PG_BUSY) || 1243 !p->valid || 1244 p->hold_count || 1245 p->wire_count || 1246 p->busy 1247 ) { 1248 p = next; 1249 continue; 1250 } 1251 } else if (op & OBSC_COLLAPSE_WAIT) { 1252 if (vm_page_sleep_busy(p, TRUE, "vmocol")) { 1253 /* 1254 * If we slept, anything could have 1255 * happened. Since the object is 1256 * marked dead, the backing offset 1257 * should not have changed so we 1258 * just restart our scan. 1259 */ 1260 p = TAILQ_FIRST(&backing_object->memq); 1261 continue; 1262 } 1263 } 1264 1265 /* 1266 * Busy the page 1267 */ 1268 vm_page_busy(p); 1269 1270 KASSERT( 1271 p->object == backing_object, 1272 ("vm_object_qcollapse(): object mismatch") 1273 ); 1274 1275 /* 1276 * Destroy any associated swap 1277 */ 1278 if (backing_object->type == OBJT_SWAP) { 1279 swap_pager_freespace( 1280 backing_object, 1281 p->pindex, 1282 1 1283 ); 1284 } 1285 1286 if ( 1287 p->pindex < backing_offset_index || 1288 new_pindex >= object->size 1289 ) { 1290 /* 1291 * Page is out of the parent object's range, we 1292 * can simply destroy it. 1293 */ 1294 vm_page_protect(p, VM_PROT_NONE); 1295 vm_page_free(p); 1296 p = next; 1297 continue; 1298 } 1299 1300 pp = vm_page_lookup(object, new_pindex); 1301 if ( 1302 pp != NULL || 1303 vm_pager_has_page(object, new_pindex, NULL, NULL) 1304 ) { 1305 /* 1306 * page already exists in parent OR swap exists 1307 * for this location in the parent. Destroy 1308 * the original page from the backing object. 1309 * 1310 * Leave the parent's page alone 1311 */ 1312 vm_page_protect(p, VM_PROT_NONE); 1313 vm_page_free(p); 1314 p = next; 1315 continue; 1316 } 1317 1318 /* 1319 * Page does not exist in parent, rename the 1320 * page from the backing object to the main object. 1321 * 1322 * If the page was mapped to a process, it can remain 1323 * mapped through the rename. 1324 */ 1325 if ((p->queue - p->pc) == PQ_CACHE) 1326 vm_page_deactivate(p); 1327 1328 vm_page_rename(p, object, new_pindex); 1329 /* page automatically made dirty by rename */ 1330 } 1331 p = next; 1332 } 1333 splx(s); 1334 return(r); 1335 } 1336 1337 1338 /* 1339 * this version of collapse allows the operation to occur earlier and 1340 * when paging_in_progress is true for an object... This is not a complete 1341 * operation, but should plug 99.9% of the rest of the leaks. 1342 */ 1343 static void 1344 vm_object_qcollapse(vm_object_t object) 1345 { 1346 vm_object_t backing_object = object->backing_object; 1347 1348 GIANT_REQUIRED; 1349 1350 if (backing_object->ref_count != 1) 1351 return; 1352 1353 backing_object->ref_count += 2; 1354 1355 vm_object_backing_scan(object, OBSC_COLLAPSE_NOWAIT); 1356 1357 backing_object->ref_count -= 2; 1358 } 1359 1360 /* 1361 * vm_object_collapse: 1362 * 1363 * Collapse an object with the object backing it. 1364 * Pages in the backing object are moved into the 1365 * parent, and the backing object is deallocated. 1366 */ 1367 void 1368 vm_object_collapse(vm_object_t object) 1369 { 1370 GIANT_REQUIRED; 1371 1372 while (TRUE) { 1373 vm_object_t backing_object; 1374 1375 /* 1376 * Verify that the conditions are right for collapse: 1377 * 1378 * The object exists and the backing object exists. 1379 */ 1380 if (object == NULL) 1381 break; 1382 1383 if ((backing_object = object->backing_object) == NULL) 1384 break; 1385 1386 /* 1387 * we check the backing object first, because it is most likely 1388 * not collapsable. 1389 */ 1390 if (backing_object->handle != NULL || 1391 (backing_object->type != OBJT_DEFAULT && 1392 backing_object->type != OBJT_SWAP) || 1393 (backing_object->flags & OBJ_DEAD) || 1394 object->handle != NULL || 1395 (object->type != OBJT_DEFAULT && 1396 object->type != OBJT_SWAP) || 1397 (object->flags & OBJ_DEAD)) { 1398 break; 1399 } 1400 1401 if ( 1402 object->paging_in_progress != 0 || 1403 backing_object->paging_in_progress != 0 1404 ) { 1405 vm_object_qcollapse(object); 1406 break; 1407 } 1408 1409 /* 1410 * We know that we can either collapse the backing object (if 1411 * the parent is the only reference to it) or (perhaps) have 1412 * the parent bypass the object if the parent happens to shadow 1413 * all the resident pages in the entire backing object. 1414 * 1415 * This is ignoring pager-backed pages such as swap pages. 1416 * vm_object_backing_scan fails the shadowing test in this 1417 * case. 1418 */ 1419 1420 if (backing_object->ref_count == 1) { 1421 /* 1422 * If there is exactly one reference to the backing 1423 * object, we can collapse it into the parent. 1424 */ 1425 1426 vm_object_backing_scan(object, OBSC_COLLAPSE_WAIT); 1427 1428 /* 1429 * Move the pager from backing_object to object. 1430 */ 1431 1432 if (backing_object->type == OBJT_SWAP) { 1433 vm_object_pip_add(backing_object, 1); 1434 1435 /* 1436 * scrap the paging_offset junk and do a 1437 * discrete copy. This also removes major 1438 * assumptions about how the swap-pager 1439 * works from where it doesn't belong. The 1440 * new swapper is able to optimize the 1441 * destroy-source case. 1442 */ 1443 1444 vm_object_pip_add(object, 1); 1445 swap_pager_copy( 1446 backing_object, 1447 object, 1448 OFF_TO_IDX(object->backing_object_offset), TRUE); 1449 vm_object_pip_wakeup(object); 1450 1451 vm_object_pip_wakeup(backing_object); 1452 } 1453 /* 1454 * Object now shadows whatever backing_object did. 1455 * Note that the reference to 1456 * backing_object->backing_object moves from within 1457 * backing_object to within object. 1458 */ 1459 1460 TAILQ_REMOVE( 1461 &object->backing_object->shadow_head, 1462 object, 1463 shadow_list 1464 ); 1465 object->backing_object->shadow_count--; 1466 object->backing_object->generation++; 1467 if (backing_object->backing_object) { 1468 TAILQ_REMOVE( 1469 &backing_object->backing_object->shadow_head, 1470 backing_object, 1471 shadow_list 1472 ); 1473 backing_object->backing_object->shadow_count--; 1474 backing_object->backing_object->generation++; 1475 } 1476 object->backing_object = backing_object->backing_object; 1477 if (object->backing_object) { 1478 TAILQ_INSERT_TAIL( 1479 &object->backing_object->shadow_head, 1480 object, 1481 shadow_list 1482 ); 1483 object->backing_object->shadow_count++; 1484 object->backing_object->generation++; 1485 } 1486 1487 object->backing_object_offset += 1488 backing_object->backing_object_offset; 1489 1490 /* 1491 * Discard backing_object. 1492 * 1493 * Since the backing object has no pages, no pager left, 1494 * and no object references within it, all that is 1495 * necessary is to dispose of it. 1496 */ 1497 KASSERT(backing_object->ref_count == 1, ("backing_object %p was somehow re-referenced during collapse!", backing_object)); 1498 KASSERT(TAILQ_FIRST(&backing_object->memq) == NULL, ("backing_object %p somehow has left over pages during collapse!", backing_object)); 1499 1500 TAILQ_REMOVE( 1501 &vm_object_list, 1502 backing_object, 1503 object_list 1504 ); 1505 vm_object_count--; 1506 1507 zfree(obj_zone, backing_object); 1508 1509 object_collapses++; 1510 } else { 1511 vm_object_t new_backing_object; 1512 1513 /* 1514 * If we do not entirely shadow the backing object, 1515 * there is nothing we can do so we give up. 1516 */ 1517 1518 if (vm_object_backing_scan(object, OBSC_TEST_ALL_SHADOWED) == 0) { 1519 break; 1520 } 1521 1522 /* 1523 * Make the parent shadow the next object in the 1524 * chain. Deallocating backing_object will not remove 1525 * it, since its reference count is at least 2. 1526 */ 1527 1528 TAILQ_REMOVE( 1529 &backing_object->shadow_head, 1530 object, 1531 shadow_list 1532 ); 1533 backing_object->shadow_count--; 1534 backing_object->generation++; 1535 1536 new_backing_object = backing_object->backing_object; 1537 if ((object->backing_object = new_backing_object) != NULL) { 1538 vm_object_reference(new_backing_object); 1539 TAILQ_INSERT_TAIL( 1540 &new_backing_object->shadow_head, 1541 object, 1542 shadow_list 1543 ); 1544 new_backing_object->shadow_count++; 1545 new_backing_object->generation++; 1546 object->backing_object_offset += 1547 backing_object->backing_object_offset; 1548 } 1549 1550 /* 1551 * Drop the reference count on backing_object. Since 1552 * its ref_count was at least 2, it will not vanish; 1553 * so we don't need to call vm_object_deallocate, but 1554 * we do anyway. 1555 */ 1556 vm_object_deallocate(backing_object); 1557 object_bypasses++; 1558 } 1559 1560 /* 1561 * Try again with this object's new backing object. 1562 */ 1563 } 1564 } 1565 1566 /* 1567 * vm_object_page_remove: [internal] 1568 * 1569 * Removes all physical pages in the specified 1570 * object range from the object's list of pages. 1571 * 1572 * The object must be locked. 1573 */ 1574 void 1575 vm_object_page_remove(vm_object_t object, vm_pindex_t start, vm_pindex_t end, boolean_t clean_only) 1576 { 1577 vm_page_t p, next; 1578 unsigned int size; 1579 int all; 1580 1581 GIANT_REQUIRED; 1582 1583 if (object == NULL || 1584 object->resident_page_count == 0) 1585 return; 1586 1587 all = ((end == 0) && (start == 0)); 1588 1589 /* 1590 * Since physically-backed objects do not use managed pages, we can't 1591 * remove pages from the object (we must instead remove the page 1592 * references, and then destroy the object). 1593 */ 1594 KASSERT(object->type != OBJT_PHYS, ("attempt to remove pages from a physical object")); 1595 1596 vm_object_pip_add(object, 1); 1597 again: 1598 size = end - start; 1599 if (all || size > object->resident_page_count / 4) { 1600 for (p = TAILQ_FIRST(&object->memq); p != NULL; p = next) { 1601 next = TAILQ_NEXT(p, listq); 1602 if (all || ((start <= p->pindex) && (p->pindex < end))) { 1603 if (p->wire_count != 0) { 1604 vm_page_protect(p, VM_PROT_NONE); 1605 if (!clean_only) 1606 p->valid = 0; 1607 continue; 1608 } 1609 1610 /* 1611 * The busy flags are only cleared at 1612 * interrupt -- minimize the spl transitions 1613 */ 1614 1615 if (vm_page_sleep_busy(p, TRUE, "vmopar")) 1616 goto again; 1617 1618 if (clean_only && p->valid) { 1619 vm_page_test_dirty(p); 1620 if (p->valid & p->dirty) 1621 continue; 1622 } 1623 1624 vm_page_busy(p); 1625 vm_page_protect(p, VM_PROT_NONE); 1626 vm_page_free(p); 1627 } 1628 } 1629 } else { 1630 while (size > 0) { 1631 if ((p = vm_page_lookup(object, start)) != 0) { 1632 1633 if (p->wire_count != 0) { 1634 vm_page_protect(p, VM_PROT_NONE); 1635 if (!clean_only) 1636 p->valid = 0; 1637 start += 1; 1638 size -= 1; 1639 continue; 1640 } 1641 1642 /* 1643 * The busy flags are only cleared at 1644 * interrupt -- minimize the spl transitions 1645 */ 1646 if (vm_page_sleep_busy(p, TRUE, "vmopar")) 1647 goto again; 1648 1649 if (clean_only && p->valid) { 1650 vm_page_test_dirty(p); 1651 if (p->valid & p->dirty) { 1652 start += 1; 1653 size -= 1; 1654 continue; 1655 } 1656 } 1657 1658 vm_page_busy(p); 1659 vm_page_protect(p, VM_PROT_NONE); 1660 vm_page_free(p); 1661 } 1662 start += 1; 1663 size -= 1; 1664 } 1665 } 1666 vm_object_pip_wakeup(object); 1667 } 1668 1669 /* 1670 * Routine: vm_object_coalesce 1671 * Function: Coalesces two objects backing up adjoining 1672 * regions of memory into a single object. 1673 * 1674 * returns TRUE if objects were combined. 1675 * 1676 * NOTE: Only works at the moment if the second object is NULL - 1677 * if it's not, which object do we lock first? 1678 * 1679 * Parameters: 1680 * prev_object First object to coalesce 1681 * prev_offset Offset into prev_object 1682 * next_object Second object into coalesce 1683 * next_offset Offset into next_object 1684 * 1685 * prev_size Size of reference to prev_object 1686 * next_size Size of reference to next_object 1687 * 1688 * Conditions: 1689 * The object must *not* be locked. 1690 */ 1691 boolean_t 1692 vm_object_coalesce(vm_object_t prev_object, vm_pindex_t prev_pindex, vm_size_t prev_size, vm_size_t next_size) 1693 { 1694 vm_pindex_t next_pindex; 1695 1696 GIANT_REQUIRED; 1697 1698 if (prev_object == NULL) { 1699 return (TRUE); 1700 } 1701 1702 if (prev_object->type != OBJT_DEFAULT && 1703 prev_object->type != OBJT_SWAP) { 1704 return (FALSE); 1705 } 1706 1707 /* 1708 * Try to collapse the object first 1709 */ 1710 vm_object_collapse(prev_object); 1711 1712 /* 1713 * Can't coalesce if: . more than one reference . paged out . shadows 1714 * another object . has a copy elsewhere (any of which mean that the 1715 * pages not mapped to prev_entry may be in use anyway) 1716 */ 1717 1718 if (prev_object->backing_object != NULL) { 1719 return (FALSE); 1720 } 1721 1722 prev_size >>= PAGE_SHIFT; 1723 next_size >>= PAGE_SHIFT; 1724 next_pindex = prev_pindex + prev_size; 1725 1726 if ((prev_object->ref_count > 1) && 1727 (prev_object->size != next_pindex)) { 1728 return (FALSE); 1729 } 1730 1731 /* 1732 * Remove any pages that may still be in the object from a previous 1733 * deallocation. 1734 */ 1735 if (next_pindex < prev_object->size) { 1736 vm_object_page_remove(prev_object, 1737 next_pindex, 1738 next_pindex + next_size, FALSE); 1739 if (prev_object->type == OBJT_SWAP) 1740 swap_pager_freespace(prev_object, 1741 next_pindex, next_size); 1742 } 1743 1744 /* 1745 * Extend the object if necessary. 1746 */ 1747 if (next_pindex + next_size > prev_object->size) 1748 prev_object->size = next_pindex + next_size; 1749 1750 return (TRUE); 1751 } 1752 1753 void 1754 vm_object_set_writeable_dirty(vm_object_t object) 1755 { 1756 struct vnode *vp; 1757 1758 vm_object_set_flag(object, OBJ_WRITEABLE|OBJ_MIGHTBEDIRTY); 1759 if (object->type == OBJT_VNODE && 1760 (vp = (struct vnode *)object->handle) != NULL) { 1761 if ((vp->v_flag & VOBJDIRTY) == 0) { 1762 mtx_lock(&vp->v_interlock); 1763 vp->v_flag |= VOBJDIRTY; 1764 mtx_unlock(&vp->v_interlock); 1765 } 1766 } 1767 } 1768 1769 #include "opt_ddb.h" 1770 #ifdef DDB 1771 #include <sys/kernel.h> 1772 1773 #include <sys/cons.h> 1774 1775 #include <ddb/ddb.h> 1776 1777 static int 1778 _vm_object_in_map(vm_map_t map, vm_object_t object, vm_map_entry_t entry) 1779 { 1780 vm_map_t tmpm; 1781 vm_map_entry_t tmpe; 1782 vm_object_t obj; 1783 int entcount; 1784 1785 if (map == 0) 1786 return 0; 1787 1788 if (entry == 0) { 1789 tmpe = map->header.next; 1790 entcount = map->nentries; 1791 while (entcount-- && (tmpe != &map->header)) { 1792 if( _vm_object_in_map(map, object, tmpe)) { 1793 return 1; 1794 } 1795 tmpe = tmpe->next; 1796 } 1797 } else if (entry->eflags & MAP_ENTRY_IS_SUB_MAP) { 1798 tmpm = entry->object.sub_map; 1799 tmpe = tmpm->header.next; 1800 entcount = tmpm->nentries; 1801 while (entcount-- && tmpe != &tmpm->header) { 1802 if( _vm_object_in_map(tmpm, object, tmpe)) { 1803 return 1; 1804 } 1805 tmpe = tmpe->next; 1806 } 1807 } else if ((obj = entry->object.vm_object) != NULL) { 1808 for (; obj; obj = obj->backing_object) 1809 if( obj == object) { 1810 return 1; 1811 } 1812 } 1813 return 0; 1814 } 1815 1816 static int 1817 vm_object_in_map(vm_object_t object) 1818 { 1819 struct proc *p; 1820 1821 /* sx_slock(&allproc_lock); */ 1822 LIST_FOREACH(p, &allproc, p_list) { 1823 if( !p->p_vmspace /* || (p->p_flag & (P_SYSTEM|P_WEXIT)) */) 1824 continue; 1825 if( _vm_object_in_map(&p->p_vmspace->vm_map, object, 0)) { 1826 /* sx_sunlock(&allproc_lock); */ 1827 return 1; 1828 } 1829 } 1830 /* sx_sunlock(&allproc_lock); */ 1831 if( _vm_object_in_map( kernel_map, object, 0)) 1832 return 1; 1833 if( _vm_object_in_map( kmem_map, object, 0)) 1834 return 1; 1835 if( _vm_object_in_map( pager_map, object, 0)) 1836 return 1; 1837 if( _vm_object_in_map( buffer_map, object, 0)) 1838 return 1; 1839 return 0; 1840 } 1841 1842 DB_SHOW_COMMAND(vmochk, vm_object_check) 1843 { 1844 vm_object_t object; 1845 1846 /* 1847 * make sure that internal objs are in a map somewhere 1848 * and none have zero ref counts. 1849 */ 1850 TAILQ_FOREACH(object, &vm_object_list, object_list) { 1851 if (object->handle == NULL && 1852 (object->type == OBJT_DEFAULT || object->type == OBJT_SWAP)) { 1853 if (object->ref_count == 0) { 1854 db_printf("vmochk: internal obj has zero ref count: %ld\n", 1855 (long)object->size); 1856 } 1857 if (!vm_object_in_map(object)) { 1858 db_printf( 1859 "vmochk: internal obj is not in a map: " 1860 "ref: %d, size: %lu: 0x%lx, backing_object: %p\n", 1861 object->ref_count, (u_long)object->size, 1862 (u_long)object->size, 1863 (void *)object->backing_object); 1864 } 1865 } 1866 } 1867 } 1868 1869 /* 1870 * vm_object_print: [ debug ] 1871 */ 1872 DB_SHOW_COMMAND(object, vm_object_print_static) 1873 { 1874 /* XXX convert args. */ 1875 vm_object_t object = (vm_object_t)addr; 1876 boolean_t full = have_addr; 1877 1878 vm_page_t p; 1879 1880 /* XXX count is an (unused) arg. Avoid shadowing it. */ 1881 #define count was_count 1882 1883 int count; 1884 1885 if (object == NULL) 1886 return; 1887 1888 db_iprintf( 1889 "Object %p: type=%d, size=0x%lx, res=%d, ref=%d, flags=0x%x\n", 1890 object, (int)object->type, (u_long)object->size, 1891 object->resident_page_count, object->ref_count, object->flags); 1892 /* 1893 * XXX no %qd in kernel. Truncate object->backing_object_offset. 1894 */ 1895 db_iprintf(" sref=%d, backing_object(%d)=(%p)+0x%lx\n", 1896 object->shadow_count, 1897 object->backing_object ? object->backing_object->ref_count : 0, 1898 object->backing_object, (long)object->backing_object_offset); 1899 1900 if (!full) 1901 return; 1902 1903 db_indent += 2; 1904 count = 0; 1905 TAILQ_FOREACH(p, &object->memq, listq) { 1906 if (count == 0) 1907 db_iprintf("memory:="); 1908 else if (count == 6) { 1909 db_printf("\n"); 1910 db_iprintf(" ..."); 1911 count = 0; 1912 } else 1913 db_printf(","); 1914 count++; 1915 1916 db_printf("(off=0x%lx,page=0x%lx)", 1917 (u_long) p->pindex, (u_long) VM_PAGE_TO_PHYS(p)); 1918 } 1919 if (count != 0) 1920 db_printf("\n"); 1921 db_indent -= 2; 1922 } 1923 1924 /* XXX. */ 1925 #undef count 1926 1927 /* XXX need this non-static entry for calling from vm_map_print. */ 1928 void 1929 vm_object_print( 1930 /* db_expr_t */ long addr, 1931 boolean_t have_addr, 1932 /* db_expr_t */ long count, 1933 char *modif) 1934 { 1935 vm_object_print_static(addr, have_addr, count, modif); 1936 } 1937 1938 DB_SHOW_COMMAND(vmopag, vm_object_print_pages) 1939 { 1940 vm_object_t object; 1941 int nl = 0; 1942 int c; 1943 1944 TAILQ_FOREACH(object, &vm_object_list, object_list) { 1945 vm_pindex_t idx, fidx; 1946 vm_pindex_t osize; 1947 vm_offset_t pa = -1, padiff; 1948 int rcount; 1949 vm_page_t m; 1950 1951 db_printf("new object: %p\n", (void *)object); 1952 if ( nl > 18) { 1953 c = cngetc(); 1954 if (c != ' ') 1955 return; 1956 nl = 0; 1957 } 1958 nl++; 1959 rcount = 0; 1960 fidx = 0; 1961 osize = object->size; 1962 if (osize > 128) 1963 osize = 128; 1964 for (idx = 0; idx < osize; idx++) { 1965 m = vm_page_lookup(object, idx); 1966 if (m == NULL) { 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 rcount = 0; 1978 } 1979 continue; 1980 } 1981 1982 1983 if (rcount && 1984 (VM_PAGE_TO_PHYS(m) == pa + rcount * PAGE_SIZE)) { 1985 ++rcount; 1986 continue; 1987 } 1988 if (rcount) { 1989 padiff = pa + rcount * PAGE_SIZE - VM_PAGE_TO_PHYS(m); 1990 padiff >>= PAGE_SHIFT; 1991 padiff &= PQ_L2_MASK; 1992 if (padiff == 0) { 1993 pa = VM_PAGE_TO_PHYS(m) - rcount * PAGE_SIZE; 1994 ++rcount; 1995 continue; 1996 } 1997 db_printf(" index(%ld)run(%d)pa(0x%lx)", 1998 (long)fidx, rcount, (long)pa); 1999 db_printf("pd(%ld)\n", (long)padiff); 2000 if ( nl > 18) { 2001 c = cngetc(); 2002 if (c != ' ') 2003 return; 2004 nl = 0; 2005 } 2006 nl++; 2007 } 2008 fidx = idx; 2009 pa = VM_PAGE_TO_PHYS(m); 2010 rcount = 1; 2011 } 2012 if (rcount) { 2013 db_printf(" index(%ld)run(%d)pa(0x%lx)\n", 2014 (long)fidx, rcount, (long)pa); 2015 if ( nl > 18) { 2016 c = cngetc(); 2017 if (c != ' ') 2018 return; 2019 nl = 0; 2020 } 2021 nl++; 2022 } 2023 } 2024 } 2025 #endif /* DDB */ 2026