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/swap_pager.h> 94 #include <vm/vm_kern.h> 95 #include <vm/vm_extern.h> 96 #include <vm/uma.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 vm_object_t kernel_object; 142 vm_object_t kmem_object; 143 static struct vm_object kernel_object_store; 144 static struct vm_object kmem_object_store; 145 extern int vm_pageout_page_count; 146 147 static long object_collapses; 148 static long object_bypasses; 149 static int next_index; 150 static int object_hash_rand; 151 static uma_zone_t obj_zone; 152 #define VM_OBJECTS_INIT 256 153 154 static void vm_object_zinit(void *mem, int size); 155 156 #ifdef INVARIANTS 157 static void vm_object_zdtor(void *mem, int size, void *arg); 158 159 static void 160 vm_object_zdtor(void *mem, int size, void *arg) 161 { 162 vm_object_t object; 163 164 object = (vm_object_t)mem; 165 KASSERT(object->paging_in_progress == 0, 166 ("object %p paging_in_progress = %d", 167 object, object->paging_in_progress)); 168 KASSERT(object->resident_page_count == 0, 169 ("object %p resident_page_count = %d", 170 object, object->resident_page_count)); 171 KASSERT(object->shadow_count == 0, 172 ("object %p shadow_count = %d", 173 object, object->shadow_count)); 174 } 175 #endif 176 177 static void 178 vm_object_zinit(void *mem, int size) 179 { 180 vm_object_t object; 181 182 object = (vm_object_t)mem; 183 184 /* These are true for any object that has been freed */ 185 object->paging_in_progress = 0; 186 object->resident_page_count = 0; 187 object->shadow_count = 0; 188 } 189 190 void 191 _vm_object_allocate(objtype_t type, vm_size_t size, vm_object_t object) 192 { 193 int incr; 194 195 GIANT_REQUIRED; 196 197 TAILQ_INIT(&object->memq); 198 TAILQ_INIT(&object->shadow_head); 199 200 object->type = type; 201 object->size = size; 202 object->ref_count = 1; 203 object->flags = 0; 204 if ((object->type == OBJT_DEFAULT) || (object->type == OBJT_SWAP)) 205 vm_object_set_flag(object, OBJ_ONEMAPPING); 206 object->pg_color = next_index; 207 if (size > (PQ_L2_SIZE / 3 + PQ_PRIME1)) 208 incr = PQ_L2_SIZE / 3 + PQ_PRIME1; 209 else 210 incr = size; 211 next_index = (next_index + incr) & PQ_L2_MASK; 212 object->handle = NULL; 213 object->backing_object = NULL; 214 object->backing_object_offset = (vm_ooffset_t) 0; 215 /* 216 * Try to generate a number that will spread objects out in the 217 * hash table. We 'wipe' new objects across the hash in 128 page 218 * increments plus 1 more to offset it a little more by the time 219 * it wraps around. 220 */ 221 object->hash_rand = object_hash_rand - 129; 222 223 object->generation++; 224 225 TAILQ_INSERT_TAIL(&vm_object_list, object, object_list); 226 227 object_hash_rand = object->hash_rand; 228 } 229 230 /* 231 * vm_object_init: 232 * 233 * Initialize the VM objects module. 234 */ 235 void 236 vm_object_init(void) 237 { 238 GIANT_REQUIRED; 239 240 TAILQ_INIT(&vm_object_list); 241 mtx_init(&vm_object_list_mtx, "vm object_list", MTX_DEF); 242 243 kernel_object = &kernel_object_store; 244 _vm_object_allocate(OBJT_DEFAULT, OFF_TO_IDX(VM_MAX_KERNEL_ADDRESS - VM_MIN_KERNEL_ADDRESS), 245 kernel_object); 246 247 kmem_object = &kmem_object_store; 248 _vm_object_allocate(OBJT_DEFAULT, OFF_TO_IDX(VM_MAX_KERNEL_ADDRESS - VM_MIN_KERNEL_ADDRESS), 249 kmem_object); 250 obj_zone = uma_zcreate("VM OBJECT", sizeof (struct vm_object), NULL, 251 #ifdef INVARIANTS 252 vm_object_zdtor, 253 #else 254 NULL, 255 #endif 256 vm_object_zinit, NULL, UMA_ALIGN_PTR, UMA_ZONE_NOFREE); 257 uma_prealloc(obj_zone, VM_OBJECTS_INIT); 258 } 259 260 void 261 vm_object_init2(void) 262 { 263 } 264 265 void 266 vm_object_set_flag(vm_object_t object, u_short bits) 267 { 268 GIANT_REQUIRED; 269 object->flags |= bits; 270 } 271 272 void 273 vm_object_clear_flag(vm_object_t object, u_short bits) 274 { 275 GIANT_REQUIRED; 276 object->flags &= ~bits; 277 } 278 279 void 280 vm_object_pip_add(vm_object_t object, short i) 281 { 282 GIANT_REQUIRED; 283 object->paging_in_progress += i; 284 } 285 286 void 287 vm_object_pip_subtract(vm_object_t object, short i) 288 { 289 GIANT_REQUIRED; 290 object->paging_in_progress -= i; 291 } 292 293 void 294 vm_object_pip_wakeup(vm_object_t object) 295 { 296 GIANT_REQUIRED; 297 object->paging_in_progress--; 298 if ((object->flags & OBJ_PIPWNT) && object->paging_in_progress == 0) { 299 vm_object_clear_flag(object, OBJ_PIPWNT); 300 wakeup(object); 301 } 302 } 303 304 void 305 vm_object_pip_wakeupn(vm_object_t object, short i) 306 { 307 GIANT_REQUIRED; 308 if (i) 309 object->paging_in_progress -= i; 310 if ((object->flags & OBJ_PIPWNT) && object->paging_in_progress == 0) { 311 vm_object_clear_flag(object, OBJ_PIPWNT); 312 wakeup(object); 313 } 314 } 315 316 void 317 vm_object_pip_sleep(vm_object_t object, char *waitid) 318 { 319 GIANT_REQUIRED; 320 if (object->paging_in_progress) { 321 int s = splvm(); 322 if (object->paging_in_progress) { 323 vm_object_set_flag(object, OBJ_PIPWNT); 324 tsleep(object, PVM, waitid, 0); 325 } 326 splx(s); 327 } 328 } 329 330 void 331 vm_object_pip_wait(vm_object_t object, char *waitid) 332 { 333 GIANT_REQUIRED; 334 while (object->paging_in_progress) 335 vm_object_pip_sleep(object, waitid); 336 } 337 338 /* 339 * vm_object_allocate: 340 * 341 * Returns a new object with the given size. 342 */ 343 vm_object_t 344 vm_object_allocate(objtype_t type, vm_size_t size) 345 { 346 vm_object_t result; 347 348 GIANT_REQUIRED; 349 350 result = (vm_object_t) uma_zalloc(obj_zone, M_WAITOK); 351 _vm_object_allocate(type, size, result); 352 353 return (result); 354 } 355 356 357 /* 358 * vm_object_reference: 359 * 360 * Gets another reference to the given object. 361 */ 362 void 363 vm_object_reference(vm_object_t object) 364 { 365 GIANT_REQUIRED; 366 367 if (object == NULL) 368 return; 369 370 #if 0 371 /* object can be re-referenced during final cleaning */ 372 KASSERT(!(object->flags & OBJ_DEAD), 373 ("vm_object_reference: attempting to reference dead obj")); 374 #endif 375 376 object->ref_count++; 377 if (object->type == OBJT_VNODE) { 378 while (vget((struct vnode *) object->handle, LK_RETRY|LK_NOOBJ, curthread)) { 379 printf("vm_object_reference: delay in getting object\n"); 380 } 381 } 382 } 383 384 /* 385 * handle deallocating a object of type OBJT_VNODE 386 */ 387 void 388 vm_object_vndeallocate(vm_object_t object) 389 { 390 struct vnode *vp = (struct vnode *) object->handle; 391 392 GIANT_REQUIRED; 393 KASSERT(object->type == OBJT_VNODE, 394 ("vm_object_vndeallocate: not a vnode object")); 395 KASSERT(vp != NULL, ("vm_object_vndeallocate: missing vp")); 396 #ifdef INVARIANTS 397 if (object->ref_count == 0) { 398 vprint("vm_object_vndeallocate", vp); 399 panic("vm_object_vndeallocate: bad object reference count"); 400 } 401 #endif 402 403 object->ref_count--; 404 if (object->ref_count == 0) { 405 vp->v_flag &= ~VTEXT; 406 vm_object_clear_flag(object, OBJ_OPT); 407 } 408 /* 409 * vrele may need a vop lock 410 */ 411 vrele(vp); 412 } 413 414 /* 415 * vm_object_deallocate: 416 * 417 * Release a reference to the specified object, 418 * gained either through a vm_object_allocate 419 * or a vm_object_reference call. When all references 420 * are gone, storage associated with this object 421 * may be relinquished. 422 * 423 * No object may be locked. 424 */ 425 void 426 vm_object_deallocate(vm_object_t object) 427 { 428 vm_object_t temp; 429 430 GIANT_REQUIRED; 431 432 while (object != NULL) { 433 434 if (object->type == OBJT_VNODE) { 435 vm_object_vndeallocate(object); 436 return; 437 } 438 439 KASSERT(object->ref_count != 0, 440 ("vm_object_deallocate: object deallocated too many times: %d", object->type)); 441 442 /* 443 * If the reference count goes to 0 we start calling 444 * vm_object_terminate() on the object chain. 445 * A ref count of 1 may be a special case depending on the 446 * shadow count being 0 or 1. 447 */ 448 object->ref_count--; 449 if (object->ref_count > 1) { 450 return; 451 } else if (object->ref_count == 1) { 452 if (object->shadow_count == 0) { 453 vm_object_set_flag(object, OBJ_ONEMAPPING); 454 } else if ((object->shadow_count == 1) && 455 (object->handle == NULL) && 456 (object->type == OBJT_DEFAULT || 457 object->type == OBJT_SWAP)) { 458 vm_object_t robject; 459 460 robject = TAILQ_FIRST(&object->shadow_head); 461 KASSERT(robject != NULL, 462 ("vm_object_deallocate: ref_count: %d, shadow_count: %d", 463 object->ref_count, 464 object->shadow_count)); 465 if ((robject->handle == NULL) && 466 (robject->type == OBJT_DEFAULT || 467 robject->type == OBJT_SWAP)) { 468 469 robject->ref_count++; 470 471 while ( 472 robject->paging_in_progress || 473 object->paging_in_progress 474 ) { 475 vm_object_pip_sleep(robject, "objde1"); 476 vm_object_pip_sleep(object, "objde2"); 477 } 478 479 if (robject->ref_count == 1) { 480 robject->ref_count--; 481 object = robject; 482 goto doterm; 483 } 484 485 object = robject; 486 vm_object_collapse(object); 487 continue; 488 } 489 } 490 491 return; 492 493 } 494 495 doterm: 496 497 temp = object->backing_object; 498 if (temp) { 499 TAILQ_REMOVE(&temp->shadow_head, object, shadow_list); 500 temp->shadow_count--; 501 if (temp->ref_count == 0) 502 vm_object_clear_flag(temp, OBJ_OPT); 503 temp->generation++; 504 object->backing_object = NULL; 505 } 506 /* 507 * Don't double-terminate, we could be in a termination 508 * recursion due to the terminate having to sync data 509 * to disk. 510 */ 511 if ((object->flags & OBJ_DEAD) == 0) 512 vm_object_terminate(object); 513 object = temp; 514 } 515 } 516 517 /* 518 * vm_object_terminate actually destroys the specified object, freeing 519 * up all previously used resources. 520 * 521 * The object must be locked. 522 * This routine may block. 523 */ 524 void 525 vm_object_terminate(vm_object_t object) 526 { 527 vm_page_t p; 528 int s; 529 530 GIANT_REQUIRED; 531 532 /* 533 * Make sure no one uses us. 534 */ 535 vm_object_set_flag(object, OBJ_DEAD); 536 537 /* 538 * wait for the pageout daemon to be done with the object 539 */ 540 vm_object_pip_wait(object, "objtrm"); 541 542 KASSERT(!object->paging_in_progress, 543 ("vm_object_terminate: pageout in progress")); 544 545 /* 546 * Clean and free the pages, as appropriate. All references to the 547 * object are gone, so we don't need to lock it. 548 */ 549 if (object->type == OBJT_VNODE) { 550 struct vnode *vp; 551 552 /* 553 * Freeze optimized copies. 554 */ 555 vm_freeze_copyopts(object, 0, object->size); 556 557 /* 558 * Clean pages and flush buffers. 559 */ 560 vm_object_page_clean(object, 0, 0, OBJPC_SYNC); 561 562 vp = (struct vnode *) object->handle; 563 vinvalbuf(vp, V_SAVE, NOCRED, NULL, 0, 0); 564 } 565 566 KASSERT(object->ref_count == 0, 567 ("vm_object_terminate: object with references, ref_count=%d", 568 object->ref_count)); 569 570 /* 571 * Now free any remaining pages. For internal objects, this also 572 * removes them from paging queues. Don't free wired pages, just 573 * remove them from the object. 574 */ 575 s = splvm(); 576 while ((p = TAILQ_FIRST(&object->memq)) != NULL) { 577 KASSERT(!p->busy && (p->flags & PG_BUSY) == 0, 578 ("vm_object_terminate: freeing busy page %p " 579 "p->busy = %d, p->flags %x\n", p, p->busy, p->flags)); 580 if (p->wire_count == 0) { 581 vm_page_busy(p); 582 vm_page_free(p); 583 cnt.v_pfree++; 584 } else { 585 vm_page_busy(p); 586 vm_page_remove(p); 587 } 588 } 589 splx(s); 590 591 /* 592 * Let the pager know object is dead. 593 */ 594 vm_pager_deallocate(object); 595 596 /* 597 * Remove the object from the global object list. 598 */ 599 mtx_lock(&vm_object_list_mtx); 600 TAILQ_REMOVE(&vm_object_list, object, object_list); 601 mtx_unlock(&vm_object_list_mtx); 602 603 wakeup(object); 604 605 /* 606 * Free the space for the object. 607 */ 608 uma_zfree(obj_zone, object); 609 } 610 611 /* 612 * vm_object_page_clean 613 * 614 * Clean all dirty pages in the specified range of object. Leaves page 615 * on whatever queue it is currently on. If NOSYNC is set then do not 616 * write out pages with PG_NOSYNC set (originally comes from MAP_NOSYNC), 617 * leaving the object dirty. 618 * 619 * Odd semantics: if start == end, we clean everything. 620 * 621 * The object must be locked. 622 */ 623 void 624 vm_object_page_clean(vm_object_t object, vm_pindex_t start, vm_pindex_t end, int flags) 625 { 626 vm_page_t p, np; 627 vm_offset_t tstart, tend; 628 vm_pindex_t pi; 629 struct vnode *vp; 630 int clearobjflags; 631 int pagerflags; 632 int curgeneration; 633 634 GIANT_REQUIRED; 635 636 if (object->type != OBJT_VNODE || 637 (object->flags & OBJ_MIGHTBEDIRTY) == 0) 638 return; 639 640 pagerflags = (flags & (OBJPC_SYNC | OBJPC_INVAL)) ? VM_PAGER_PUT_SYNC : 0; 641 pagerflags |= (flags & OBJPC_INVAL) ? VM_PAGER_PUT_INVAL : 0; 642 643 vp = object->handle; 644 645 vm_object_set_flag(object, OBJ_CLEANING); 646 647 tstart = start; 648 if (end == 0) { 649 tend = object->size; 650 } else { 651 tend = end; 652 } 653 654 /* 655 * If the caller is smart and only msync()s a range he knows is 656 * dirty, we may be able to avoid an object scan. This results in 657 * a phenominal improvement in performance. We cannot do this 658 * as a matter of course because the object may be huge - e.g. 659 * the size might be in the gigabytes or terrabytes. 660 */ 661 if (msync_flush_flags & MSYNC_FLUSH_HARDSEQ) { 662 vm_offset_t tscan; 663 int scanlimit; 664 int scanreset; 665 666 scanreset = object->resident_page_count / EASY_SCAN_FACTOR; 667 if (scanreset < 16) 668 scanreset = 16; 669 670 scanlimit = scanreset; 671 tscan = tstart; 672 while (tscan < tend) { 673 curgeneration = object->generation; 674 p = vm_page_lookup(object, tscan); 675 if (p == NULL || p->valid == 0 || 676 (p->queue - p->pc) == PQ_CACHE) { 677 if (--scanlimit == 0) 678 break; 679 ++tscan; 680 continue; 681 } 682 vm_page_test_dirty(p); 683 if ((p->dirty & p->valid) == 0) { 684 if (--scanlimit == 0) 685 break; 686 ++tscan; 687 continue; 688 } 689 /* 690 * If we have been asked to skip nosync pages and 691 * this is a nosync page, we can't continue. 692 */ 693 if ((flags & OBJPC_NOSYNC) && (p->flags & PG_NOSYNC)) { 694 if (--scanlimit == 0) 695 break; 696 ++tscan; 697 continue; 698 } 699 scanlimit = scanreset; 700 701 /* 702 * This returns 0 if it was unable to busy the first 703 * page (i.e. had to sleep). 704 */ 705 tscan += vm_object_page_collect_flush(object, p, curgeneration, pagerflags); 706 } 707 708 /* 709 * If everything was dirty and we flushed it successfully, 710 * and the requested range is not the entire object, we 711 * don't have to mess with CLEANCHK or MIGHTBEDIRTY and can 712 * return immediately. 713 */ 714 if (tscan >= tend && (tstart || tend < object->size)) { 715 vm_object_clear_flag(object, OBJ_CLEANING); 716 return; 717 } 718 } 719 720 /* 721 * Generally set CLEANCHK interlock and make the page read-only so 722 * we can then clear the object flags. 723 * 724 * However, if this is a nosync mmap then the object is likely to 725 * stay dirty so do not mess with the page and do not clear the 726 * object flags. 727 */ 728 clearobjflags = 1; 729 730 TAILQ_FOREACH(p, &object->memq, listq) { 731 vm_page_flag_set(p, PG_CLEANCHK); 732 if ((flags & OBJPC_NOSYNC) && (p->flags & PG_NOSYNC)) 733 clearobjflags = 0; 734 else 735 vm_page_protect(p, VM_PROT_READ); 736 } 737 738 if (clearobjflags && (tstart == 0) && (tend == object->size)) { 739 struct vnode *vp; 740 741 vm_object_clear_flag(object, OBJ_WRITEABLE|OBJ_MIGHTBEDIRTY); 742 if (object->type == OBJT_VNODE && 743 (vp = (struct vnode *)object->handle) != NULL) { 744 if (vp->v_flag & VOBJDIRTY) { 745 mtx_lock(&vp->v_interlock); 746 vp->v_flag &= ~VOBJDIRTY; 747 mtx_unlock(&vp->v_interlock); 748 } 749 } 750 } 751 752 rescan: 753 curgeneration = object->generation; 754 755 for (p = TAILQ_FIRST(&object->memq); p; p = np) { 756 int n; 757 758 np = TAILQ_NEXT(p, listq); 759 760 again: 761 pi = p->pindex; 762 if (((p->flags & PG_CLEANCHK) == 0) || 763 (pi < tstart) || (pi >= tend) || 764 (p->valid == 0) || 765 ((p->queue - p->pc) == PQ_CACHE)) { 766 vm_page_flag_clear(p, PG_CLEANCHK); 767 continue; 768 } 769 770 vm_page_test_dirty(p); 771 if ((p->dirty & p->valid) == 0) { 772 vm_page_flag_clear(p, PG_CLEANCHK); 773 continue; 774 } 775 776 /* 777 * If we have been asked to skip nosync pages and this is a 778 * nosync page, skip it. Note that the object flags were 779 * not cleared in this case so we do not have to set them. 780 */ 781 if ((flags & OBJPC_NOSYNC) && (p->flags & PG_NOSYNC)) { 782 vm_page_flag_clear(p, PG_CLEANCHK); 783 continue; 784 } 785 786 n = vm_object_page_collect_flush(object, p, 787 curgeneration, pagerflags); 788 if (n == 0) 789 goto rescan; 790 791 if (object->generation != curgeneration) 792 goto rescan; 793 794 /* 795 * Try to optimize the next page. If we can't we pick up 796 * our (random) scan where we left off. 797 */ 798 if (msync_flush_flags & MSYNC_FLUSH_SOFTSEQ) { 799 if ((p = vm_page_lookup(object, pi + n)) != NULL) 800 goto again; 801 } 802 } 803 804 #if 0 805 VOP_FSYNC(vp, NULL, (pagerflags & VM_PAGER_PUT_SYNC)?MNT_WAIT:0, curproc); 806 #endif 807 808 vm_object_clear_flag(object, OBJ_CLEANING); 809 return; 810 } 811 812 static int 813 vm_object_page_collect_flush(vm_object_t object, vm_page_t p, int curgeneration, int pagerflags) 814 { 815 int runlen; 816 int s; 817 int maxf; 818 int chkb; 819 int maxb; 820 int i; 821 vm_pindex_t pi; 822 vm_page_t maf[vm_pageout_page_count]; 823 vm_page_t mab[vm_pageout_page_count]; 824 vm_page_t ma[vm_pageout_page_count]; 825 826 s = splvm(); 827 pi = p->pindex; 828 while (vm_page_sleep_busy(p, TRUE, "vpcwai")) { 829 if (object->generation != curgeneration) { 830 splx(s); 831 return(0); 832 } 833 } 834 835 maxf = 0; 836 for(i = 1; i < vm_pageout_page_count; i++) { 837 vm_page_t tp; 838 839 if ((tp = vm_page_lookup(object, pi + i)) != NULL) { 840 if ((tp->flags & PG_BUSY) || 841 (tp->flags & PG_CLEANCHK) == 0 || 842 (tp->busy != 0)) 843 break; 844 if((tp->queue - tp->pc) == PQ_CACHE) { 845 vm_page_flag_clear(tp, PG_CLEANCHK); 846 break; 847 } 848 vm_page_test_dirty(tp); 849 if ((tp->dirty & tp->valid) == 0) { 850 vm_page_flag_clear(tp, PG_CLEANCHK); 851 break; 852 } 853 maf[ i - 1 ] = tp; 854 maxf++; 855 continue; 856 } 857 break; 858 } 859 860 maxb = 0; 861 chkb = vm_pageout_page_count - maxf; 862 if (chkb) { 863 for(i = 1; i < chkb;i++) { 864 vm_page_t tp; 865 866 if ((tp = vm_page_lookup(object, pi - i)) != NULL) { 867 if ((tp->flags & PG_BUSY) || 868 (tp->flags & PG_CLEANCHK) == 0 || 869 (tp->busy != 0)) 870 break; 871 if ((tp->queue - tp->pc) == PQ_CACHE) { 872 vm_page_flag_clear(tp, PG_CLEANCHK); 873 break; 874 } 875 vm_page_test_dirty(tp); 876 if ((tp->dirty & tp->valid) == 0) { 877 vm_page_flag_clear(tp, PG_CLEANCHK); 878 break; 879 } 880 mab[ i - 1 ] = tp; 881 maxb++; 882 continue; 883 } 884 break; 885 } 886 } 887 888 for(i = 0; i < maxb; i++) { 889 int index = (maxb - i) - 1; 890 ma[index] = mab[i]; 891 vm_page_flag_clear(ma[index], PG_CLEANCHK); 892 } 893 vm_page_flag_clear(p, PG_CLEANCHK); 894 ma[maxb] = p; 895 for(i = 0; i < maxf; i++) { 896 int index = (maxb + i) + 1; 897 ma[index] = maf[i]; 898 vm_page_flag_clear(ma[index], PG_CLEANCHK); 899 } 900 runlen = maxb + maxf + 1; 901 902 splx(s); 903 vm_pageout_flush(ma, runlen, pagerflags); 904 for (i = 0; i < runlen; i++) { 905 if (ma[i]->valid & ma[i]->dirty) { 906 vm_page_protect(ma[i], VM_PROT_READ); 907 vm_page_flag_set(ma[i], PG_CLEANCHK); 908 909 /* 910 * maxf will end up being the actual number of pages 911 * we wrote out contiguously, non-inclusive of the 912 * first page. We do not count look-behind pages. 913 */ 914 if (i >= maxb + 1 && (maxf > i - maxb - 1)) 915 maxf = i - maxb - 1; 916 } 917 } 918 return(maxf + 1); 919 } 920 921 /* 922 * Same as vm_object_pmap_copy, except range checking really 923 * works, and is meant for small sections of an object. 924 * 925 * This code protects resident pages by making them read-only 926 * and is typically called on a fork or split when a page 927 * is converted to copy-on-write. 928 * 929 * NOTE: If the page is already at VM_PROT_NONE, calling 930 * vm_page_protect will have no effect. 931 */ 932 void 933 vm_object_pmap_copy_1(vm_object_t object, vm_pindex_t start, vm_pindex_t end) 934 { 935 vm_pindex_t idx; 936 vm_page_t p; 937 938 GIANT_REQUIRED; 939 940 if (object == NULL || (object->flags & OBJ_WRITEABLE) == 0) 941 return; 942 943 for (idx = start; idx < end; idx++) { 944 p = vm_page_lookup(object, idx); 945 if (p == NULL) 946 continue; 947 vm_page_protect(p, VM_PROT_READ); 948 } 949 } 950 951 /* 952 * vm_object_pmap_remove: 953 * 954 * Removes all physical pages in the specified 955 * object range from all physical maps. 956 * 957 * The object must *not* be locked. 958 */ 959 void 960 vm_object_pmap_remove(vm_object_t object, vm_pindex_t start, vm_pindex_t end) 961 { 962 vm_page_t p; 963 964 GIANT_REQUIRED; 965 if (object == NULL) 966 return; 967 TAILQ_FOREACH(p, &object->memq, listq) { 968 if (p->pindex >= start && p->pindex < end) 969 vm_page_protect(p, VM_PROT_NONE); 970 } 971 if ((start == 0) && (object->size == end)) 972 vm_object_clear_flag(object, OBJ_WRITEABLE); 973 } 974 975 /* 976 * vm_object_madvise: 977 * 978 * Implements the madvise function at the object/page level. 979 * 980 * MADV_WILLNEED (any object) 981 * 982 * Activate the specified pages if they are resident. 983 * 984 * MADV_DONTNEED (any object) 985 * 986 * Deactivate the specified pages if they are resident. 987 * 988 * MADV_FREE (OBJT_DEFAULT/OBJT_SWAP objects, 989 * OBJ_ONEMAPPING only) 990 * 991 * Deactivate and clean the specified pages if they are 992 * resident. This permits the process to reuse the pages 993 * without faulting or the kernel to reclaim the pages 994 * without I/O. 995 */ 996 void 997 vm_object_madvise(vm_object_t object, vm_pindex_t pindex, int count, int advise) 998 { 999 vm_pindex_t end, tpindex; 1000 vm_object_t tobject; 1001 vm_page_t m; 1002 1003 GIANT_REQUIRED; 1004 if (object == NULL) 1005 return; 1006 1007 end = pindex + count; 1008 1009 /* 1010 * Locate and adjust resident pages 1011 */ 1012 for (; pindex < end; pindex += 1) { 1013 relookup: 1014 tobject = object; 1015 tpindex = pindex; 1016 shadowlookup: 1017 /* 1018 * MADV_FREE only operates on OBJT_DEFAULT or OBJT_SWAP pages 1019 * and those pages must be OBJ_ONEMAPPING. 1020 */ 1021 if (advise == MADV_FREE) { 1022 if ((tobject->type != OBJT_DEFAULT && 1023 tobject->type != OBJT_SWAP) || 1024 (tobject->flags & OBJ_ONEMAPPING) == 0) { 1025 continue; 1026 } 1027 } 1028 1029 m = vm_page_lookup(tobject, tpindex); 1030 1031 if (m == NULL) { 1032 /* 1033 * There may be swap even if there is no backing page 1034 */ 1035 if (advise == MADV_FREE && tobject->type == OBJT_SWAP) 1036 swap_pager_freespace(tobject, tpindex, 1); 1037 1038 /* 1039 * next object 1040 */ 1041 tobject = tobject->backing_object; 1042 if (tobject == NULL) 1043 continue; 1044 tpindex += OFF_TO_IDX(tobject->backing_object_offset); 1045 goto shadowlookup; 1046 } 1047 1048 /* 1049 * If the page is busy or not in a normal active state, 1050 * we skip it. If the page is not managed there are no 1051 * page queues to mess with. Things can break if we mess 1052 * with pages in any of the below states. 1053 */ 1054 if ( 1055 m->hold_count || 1056 m->wire_count || 1057 (m->flags & PG_UNMANAGED) || 1058 m->valid != VM_PAGE_BITS_ALL 1059 ) { 1060 continue; 1061 } 1062 1063 if (vm_page_sleep_busy(m, TRUE, "madvpo")) 1064 goto relookup; 1065 1066 if (advise == MADV_WILLNEED) { 1067 vm_page_activate(m); 1068 } else if (advise == MADV_DONTNEED) { 1069 vm_page_dontneed(m); 1070 } else if (advise == MADV_FREE) { 1071 /* 1072 * Mark the page clean. This will allow the page 1073 * to be freed up by the system. However, such pages 1074 * are often reused quickly by malloc()/free() 1075 * so we do not do anything that would cause 1076 * a page fault if we can help it. 1077 * 1078 * Specifically, we do not try to actually free 1079 * the page now nor do we try to put it in the 1080 * cache (which would cause a page fault on reuse). 1081 * 1082 * But we do make the page is freeable as we 1083 * can without actually taking the step of unmapping 1084 * it. 1085 */ 1086 pmap_clear_modify(m); 1087 m->dirty = 0; 1088 m->act_count = 0; 1089 vm_page_dontneed(m); 1090 if (tobject->type == OBJT_SWAP) 1091 swap_pager_freespace(tobject, tpindex, 1); 1092 } 1093 } 1094 } 1095 1096 /* 1097 * vm_object_shadow: 1098 * 1099 * Create a new object which is backed by the 1100 * specified existing object range. The source 1101 * object reference is deallocated. 1102 * 1103 * The new object and offset into that object 1104 * are returned in the source parameters. 1105 */ 1106 void 1107 vm_object_shadow( 1108 vm_object_t *object, /* IN/OUT */ 1109 vm_ooffset_t *offset, /* IN/OUT */ 1110 vm_size_t length) 1111 { 1112 vm_object_t source; 1113 vm_object_t result; 1114 1115 GIANT_REQUIRED; 1116 source = *object; 1117 1118 /* 1119 * Don't create the new object if the old object isn't shared. 1120 */ 1121 if (source != NULL && 1122 source->ref_count == 1 && 1123 source->handle == NULL && 1124 (source->type == OBJT_DEFAULT || 1125 source->type == OBJT_SWAP)) 1126 return; 1127 1128 /* 1129 * Allocate a new object with the given length 1130 */ 1131 result = vm_object_allocate(OBJT_DEFAULT, length); 1132 KASSERT(result != NULL, ("vm_object_shadow: no object for shadowing")); 1133 1134 /* 1135 * The new object shadows the source object, adding a reference to it. 1136 * Our caller changes his reference to point to the new object, 1137 * removing a reference to the source object. Net result: no change 1138 * of reference count. 1139 * 1140 * Try to optimize the result object's page color when shadowing 1141 * in order to maintain page coloring consistency in the combined 1142 * shadowed object. 1143 */ 1144 result->backing_object = source; 1145 if (source) { 1146 TAILQ_INSERT_TAIL(&source->shadow_head, result, shadow_list); 1147 source->shadow_count++; 1148 source->generation++; 1149 result->pg_color = (source->pg_color + OFF_TO_IDX(*offset)) & PQ_L2_MASK; 1150 } 1151 1152 /* 1153 * Store the offset into the source object, and fix up the offset into 1154 * the new object. 1155 */ 1156 result->backing_object_offset = *offset; 1157 1158 /* 1159 * Return the new things 1160 */ 1161 *offset = 0; 1162 *object = result; 1163 } 1164 1165 #define OBSC_TEST_ALL_SHADOWED 0x0001 1166 #define OBSC_COLLAPSE_NOWAIT 0x0002 1167 #define OBSC_COLLAPSE_WAIT 0x0004 1168 1169 static __inline int 1170 vm_object_backing_scan(vm_object_t object, int op) 1171 { 1172 int s; 1173 int r = 1; 1174 vm_page_t p; 1175 vm_object_t backing_object; 1176 vm_pindex_t backing_offset_index; 1177 1178 s = splvm(); 1179 GIANT_REQUIRED; 1180 1181 backing_object = object->backing_object; 1182 backing_offset_index = OFF_TO_IDX(object->backing_object_offset); 1183 1184 /* 1185 * Initial conditions 1186 */ 1187 if (op & OBSC_TEST_ALL_SHADOWED) { 1188 /* 1189 * We do not want to have to test for the existence of 1190 * swap pages in the backing object. XXX but with the 1191 * new swapper this would be pretty easy to do. 1192 * 1193 * XXX what about anonymous MAP_SHARED memory that hasn't 1194 * been ZFOD faulted yet? If we do not test for this, the 1195 * shadow test may succeed! XXX 1196 */ 1197 if (backing_object->type != OBJT_DEFAULT) { 1198 splx(s); 1199 return (0); 1200 } 1201 } 1202 if (op & OBSC_COLLAPSE_WAIT) { 1203 vm_object_set_flag(backing_object, OBJ_DEAD); 1204 } 1205 1206 /* 1207 * Our scan 1208 */ 1209 p = TAILQ_FIRST(&backing_object->memq); 1210 while (p) { 1211 vm_page_t next = TAILQ_NEXT(p, listq); 1212 vm_pindex_t new_pindex = p->pindex - backing_offset_index; 1213 1214 if (op & OBSC_TEST_ALL_SHADOWED) { 1215 vm_page_t pp; 1216 1217 /* 1218 * Ignore pages outside the parent object's range 1219 * and outside the parent object's mapping of the 1220 * backing object. 1221 * 1222 * note that we do not busy the backing object's 1223 * page. 1224 */ 1225 if ( 1226 p->pindex < backing_offset_index || 1227 new_pindex >= object->size 1228 ) { 1229 p = next; 1230 continue; 1231 } 1232 1233 /* 1234 * See if the parent has the page or if the parent's 1235 * object pager has the page. If the parent has the 1236 * page but the page is not valid, the parent's 1237 * object pager must have the page. 1238 * 1239 * If this fails, the parent does not completely shadow 1240 * the object and we might as well give up now. 1241 */ 1242 1243 pp = vm_page_lookup(object, new_pindex); 1244 if ( 1245 (pp == NULL || pp->valid == 0) && 1246 !vm_pager_has_page(object, new_pindex, NULL, NULL) 1247 ) { 1248 r = 0; 1249 break; 1250 } 1251 } 1252 1253 /* 1254 * Check for busy page 1255 */ 1256 if (op & (OBSC_COLLAPSE_WAIT | OBSC_COLLAPSE_NOWAIT)) { 1257 vm_page_t pp; 1258 1259 if (op & OBSC_COLLAPSE_NOWAIT) { 1260 if ( 1261 (p->flags & PG_BUSY) || 1262 !p->valid || 1263 p->hold_count || 1264 p->wire_count || 1265 p->busy 1266 ) { 1267 p = next; 1268 continue; 1269 } 1270 } else if (op & OBSC_COLLAPSE_WAIT) { 1271 if (vm_page_sleep_busy(p, TRUE, "vmocol")) { 1272 /* 1273 * If we slept, anything could have 1274 * happened. Since the object is 1275 * marked dead, the backing offset 1276 * should not have changed so we 1277 * just restart our scan. 1278 */ 1279 p = TAILQ_FIRST(&backing_object->memq); 1280 continue; 1281 } 1282 } 1283 1284 /* 1285 * Busy the page 1286 */ 1287 vm_page_busy(p); 1288 1289 KASSERT( 1290 p->object == backing_object, 1291 ("vm_object_qcollapse(): object mismatch") 1292 ); 1293 1294 /* 1295 * Destroy any associated swap 1296 */ 1297 if (backing_object->type == OBJT_SWAP) { 1298 swap_pager_freespace( 1299 backing_object, 1300 p->pindex, 1301 1 1302 ); 1303 } 1304 1305 if ( 1306 p->pindex < backing_offset_index || 1307 new_pindex >= object->size 1308 ) { 1309 /* 1310 * Page is out of the parent object's range, we 1311 * can simply destroy it. 1312 */ 1313 vm_page_protect(p, VM_PROT_NONE); 1314 vm_page_free(p); 1315 p = next; 1316 continue; 1317 } 1318 1319 pp = vm_page_lookup(object, new_pindex); 1320 if ( 1321 pp != NULL || 1322 vm_pager_has_page(object, new_pindex, NULL, NULL) 1323 ) { 1324 /* 1325 * page already exists in parent OR swap exists 1326 * for this location in the parent. Destroy 1327 * the original page from the backing object. 1328 * 1329 * Leave the parent's page alone 1330 */ 1331 vm_page_protect(p, VM_PROT_NONE); 1332 vm_page_free(p); 1333 p = next; 1334 continue; 1335 } 1336 1337 /* 1338 * Page does not exist in parent, rename the 1339 * page from the backing object to the main object. 1340 * 1341 * If the page was mapped to a process, it can remain 1342 * mapped through the rename. 1343 */ 1344 if ((p->queue - p->pc) == PQ_CACHE) 1345 vm_page_deactivate(p); 1346 1347 vm_page_rename(p, object, new_pindex); 1348 /* page automatically made dirty by rename */ 1349 } 1350 p = next; 1351 } 1352 splx(s); 1353 return (r); 1354 } 1355 1356 1357 /* 1358 * this version of collapse allows the operation to occur earlier and 1359 * when paging_in_progress is true for an object... This is not a complete 1360 * operation, but should plug 99.9% of the rest of the leaks. 1361 */ 1362 static void 1363 vm_object_qcollapse(vm_object_t object) 1364 { 1365 vm_object_t backing_object = object->backing_object; 1366 1367 GIANT_REQUIRED; 1368 1369 if (backing_object->ref_count != 1) 1370 return; 1371 1372 backing_object->ref_count += 2; 1373 1374 vm_object_backing_scan(object, OBSC_COLLAPSE_NOWAIT); 1375 1376 backing_object->ref_count -= 2; 1377 } 1378 1379 /* 1380 * vm_object_collapse: 1381 * 1382 * Collapse an object with the object backing it. 1383 * Pages in the backing object are moved into the 1384 * parent, and the backing object is deallocated. 1385 */ 1386 void 1387 vm_object_collapse(vm_object_t object) 1388 { 1389 GIANT_REQUIRED; 1390 1391 while (TRUE) { 1392 vm_object_t backing_object; 1393 1394 /* 1395 * Verify that the conditions are right for collapse: 1396 * 1397 * The object exists and the backing object exists. 1398 */ 1399 if (object == NULL) 1400 break; 1401 1402 if ((backing_object = object->backing_object) == NULL) 1403 break; 1404 1405 /* 1406 * we check the backing object first, because it is most likely 1407 * not collapsable. 1408 */ 1409 if (backing_object->handle != NULL || 1410 (backing_object->type != OBJT_DEFAULT && 1411 backing_object->type != OBJT_SWAP) || 1412 (backing_object->flags & OBJ_DEAD) || 1413 object->handle != NULL || 1414 (object->type != OBJT_DEFAULT && 1415 object->type != OBJT_SWAP) || 1416 (object->flags & OBJ_DEAD)) { 1417 break; 1418 } 1419 1420 if ( 1421 object->paging_in_progress != 0 || 1422 backing_object->paging_in_progress != 0 1423 ) { 1424 vm_object_qcollapse(object); 1425 break; 1426 } 1427 1428 /* 1429 * We know that we can either collapse the backing object (if 1430 * the parent is the only reference to it) or (perhaps) have 1431 * the parent bypass the object if the parent happens to shadow 1432 * all the resident pages in the entire backing object. 1433 * 1434 * This is ignoring pager-backed pages such as swap pages. 1435 * vm_object_backing_scan fails the shadowing test in this 1436 * case. 1437 */ 1438 if (backing_object->ref_count == 1) { 1439 /* 1440 * If there is exactly one reference to the backing 1441 * object, we can collapse it into the parent. 1442 */ 1443 vm_object_backing_scan(object, OBSC_COLLAPSE_WAIT); 1444 1445 /* 1446 * Move the pager from backing_object to object. 1447 */ 1448 if (backing_object->type == OBJT_SWAP) { 1449 vm_object_pip_add(backing_object, 1); 1450 1451 /* 1452 * scrap the paging_offset junk and do a 1453 * discrete copy. This also removes major 1454 * assumptions about how the swap-pager 1455 * works from where it doesn't belong. The 1456 * new swapper is able to optimize the 1457 * destroy-source case. 1458 */ 1459 vm_object_pip_add(object, 1); 1460 swap_pager_copy( 1461 backing_object, 1462 object, 1463 OFF_TO_IDX(object->backing_object_offset), TRUE); 1464 vm_object_pip_wakeup(object); 1465 1466 vm_object_pip_wakeup(backing_object); 1467 } 1468 /* 1469 * Object now shadows whatever backing_object did. 1470 * Note that the reference to 1471 * backing_object->backing_object moves from within 1472 * backing_object to within object. 1473 */ 1474 TAILQ_REMOVE( 1475 &object->backing_object->shadow_head, 1476 object, 1477 shadow_list 1478 ); 1479 object->backing_object->shadow_count--; 1480 object->backing_object->generation++; 1481 if (backing_object->backing_object) { 1482 TAILQ_REMOVE( 1483 &backing_object->backing_object->shadow_head, 1484 backing_object, 1485 shadow_list 1486 ); 1487 backing_object->backing_object->shadow_count--; 1488 backing_object->backing_object->generation++; 1489 } 1490 object->backing_object = backing_object->backing_object; 1491 if (object->backing_object) { 1492 TAILQ_INSERT_TAIL( 1493 &object->backing_object->shadow_head, 1494 object, 1495 shadow_list 1496 ); 1497 object->backing_object->shadow_count++; 1498 object->backing_object->generation++; 1499 } 1500 1501 object->backing_object_offset += 1502 backing_object->backing_object_offset; 1503 1504 /* 1505 * Discard backing_object. 1506 * 1507 * Since the backing object has no pages, no pager left, 1508 * and no object references within it, all that is 1509 * necessary is to dispose of it. 1510 */ 1511 KASSERT(backing_object->ref_count == 1, ("backing_object %p was somehow re-referenced during collapse!", backing_object)); 1512 KASSERT(TAILQ_FIRST(&backing_object->memq) == NULL, ("backing_object %p somehow has left over pages during collapse!", backing_object)); 1513 1514 TAILQ_REMOVE( 1515 &vm_object_list, 1516 backing_object, 1517 object_list 1518 ); 1519 1520 uma_zfree(obj_zone, backing_object); 1521 1522 object_collapses++; 1523 } else { 1524 vm_object_t new_backing_object; 1525 1526 /* 1527 * If we do not entirely shadow the backing object, 1528 * there is nothing we can do so we give up. 1529 */ 1530 if (vm_object_backing_scan(object, OBSC_TEST_ALL_SHADOWED) == 0) { 1531 break; 1532 } 1533 1534 /* 1535 * Make the parent shadow the next object in the 1536 * chain. Deallocating backing_object will not remove 1537 * it, since its reference count is at least 2. 1538 */ 1539 TAILQ_REMOVE( 1540 &backing_object->shadow_head, 1541 object, 1542 shadow_list 1543 ); 1544 backing_object->shadow_count--; 1545 backing_object->generation++; 1546 1547 new_backing_object = backing_object->backing_object; 1548 if ((object->backing_object = new_backing_object) != NULL) { 1549 vm_object_reference(new_backing_object); 1550 TAILQ_INSERT_TAIL( 1551 &new_backing_object->shadow_head, 1552 object, 1553 shadow_list 1554 ); 1555 new_backing_object->shadow_count++; 1556 new_backing_object->generation++; 1557 object->backing_object_offset += 1558 backing_object->backing_object_offset; 1559 } 1560 1561 /* 1562 * Drop the reference count on backing_object. Since 1563 * its ref_count was at least 2, it will not vanish; 1564 * so we don't need to call vm_object_deallocate, but 1565 * we do anyway. 1566 */ 1567 vm_object_deallocate(backing_object); 1568 object_bypasses++; 1569 } 1570 1571 /* 1572 * Try again with this object's new backing object. 1573 */ 1574 } 1575 } 1576 1577 /* 1578 * vm_object_page_remove: [internal] 1579 * 1580 * Removes all physical pages in the specified 1581 * object range from the object's list of pages. 1582 * 1583 * The object must be locked. 1584 */ 1585 void 1586 vm_object_page_remove(vm_object_t object, vm_pindex_t start, vm_pindex_t end, boolean_t clean_only) 1587 { 1588 vm_page_t p, next; 1589 unsigned int size; 1590 int all; 1591 1592 GIANT_REQUIRED; 1593 1594 if (object == NULL || 1595 object->resident_page_count == 0) 1596 return; 1597 1598 all = ((end == 0) && (start == 0)); 1599 1600 /* 1601 * Since physically-backed objects do not use managed pages, we can't 1602 * remove pages from the object (we must instead remove the page 1603 * references, and then destroy the object). 1604 */ 1605 KASSERT(object->type != OBJT_PHYS, ("attempt to remove pages from a physical object")); 1606 1607 vm_object_pip_add(object, 1); 1608 again: 1609 size = end - start; 1610 if (all || size > object->resident_page_count / 4) { 1611 for (p = TAILQ_FIRST(&object->memq); p != NULL; p = next) { 1612 next = TAILQ_NEXT(p, listq); 1613 if (all || ((start <= p->pindex) && (p->pindex < end))) { 1614 if (p->wire_count != 0) { 1615 vm_page_protect(p, VM_PROT_NONE); 1616 if (!clean_only) 1617 p->valid = 0; 1618 continue; 1619 } 1620 1621 /* 1622 * The busy flags are only cleared at 1623 * interrupt -- minimize the spl transitions 1624 */ 1625 if (vm_page_sleep_busy(p, TRUE, "vmopar")) 1626 goto again; 1627 1628 if (clean_only && p->valid) { 1629 vm_page_test_dirty(p); 1630 if (p->valid & p->dirty) 1631 continue; 1632 } 1633 1634 vm_page_busy(p); 1635 vm_page_protect(p, VM_PROT_NONE); 1636 vm_page_free(p); 1637 } 1638 } 1639 } else { 1640 while (size > 0) { 1641 if ((p = vm_page_lookup(object, start)) != 0) { 1642 1643 if (p->wire_count != 0) { 1644 vm_page_protect(p, VM_PROT_NONE); 1645 if (!clean_only) 1646 p->valid = 0; 1647 start += 1; 1648 size -= 1; 1649 continue; 1650 } 1651 1652 /* 1653 * The busy flags are only cleared at 1654 * interrupt -- minimize the spl transitions 1655 */ 1656 if (vm_page_sleep_busy(p, TRUE, "vmopar")) 1657 goto again; 1658 1659 if (clean_only && p->valid) { 1660 vm_page_test_dirty(p); 1661 if (p->valid & p->dirty) { 1662 start += 1; 1663 size -= 1; 1664 continue; 1665 } 1666 } 1667 1668 vm_page_busy(p); 1669 vm_page_protect(p, VM_PROT_NONE); 1670 vm_page_free(p); 1671 } 1672 start += 1; 1673 size -= 1; 1674 } 1675 } 1676 vm_object_pip_wakeup(object); 1677 } 1678 1679 /* 1680 * Routine: vm_object_coalesce 1681 * Function: Coalesces two objects backing up adjoining 1682 * regions of memory into a single object. 1683 * 1684 * returns TRUE if objects were combined. 1685 * 1686 * NOTE: Only works at the moment if the second object is NULL - 1687 * if it's not, which object do we lock first? 1688 * 1689 * Parameters: 1690 * prev_object First object to coalesce 1691 * prev_offset Offset into prev_object 1692 * next_object Second object into coalesce 1693 * next_offset Offset into next_object 1694 * 1695 * prev_size Size of reference to prev_object 1696 * next_size Size of reference to next_object 1697 * 1698 * Conditions: 1699 * The object must *not* be locked. 1700 */ 1701 boolean_t 1702 vm_object_coalesce(vm_object_t prev_object, vm_pindex_t prev_pindex, vm_size_t prev_size, vm_size_t next_size) 1703 { 1704 vm_pindex_t next_pindex; 1705 1706 GIANT_REQUIRED; 1707 1708 if (prev_object == NULL) { 1709 return (TRUE); 1710 } 1711 1712 if (prev_object->type != OBJT_DEFAULT && 1713 prev_object->type != OBJT_SWAP) { 1714 return (FALSE); 1715 } 1716 1717 /* 1718 * Try to collapse the object first 1719 */ 1720 vm_object_collapse(prev_object); 1721 1722 /* 1723 * Can't coalesce if: . more than one reference . paged out . shadows 1724 * another object . has a copy elsewhere (any of which mean that the 1725 * pages not mapped to prev_entry may be in use anyway) 1726 */ 1727 if (prev_object->backing_object != NULL) { 1728 return (FALSE); 1729 } 1730 1731 prev_size >>= PAGE_SHIFT; 1732 next_size >>= PAGE_SHIFT; 1733 next_pindex = prev_pindex + prev_size; 1734 1735 if ((prev_object->ref_count > 1) && 1736 (prev_object->size != next_pindex)) { 1737 return (FALSE); 1738 } 1739 1740 /* 1741 * Remove any pages that may still be in the object from a previous 1742 * deallocation. 1743 */ 1744 if (next_pindex < prev_object->size) { 1745 vm_object_page_remove(prev_object, 1746 next_pindex, 1747 next_pindex + next_size, FALSE); 1748 if (prev_object->type == OBJT_SWAP) 1749 swap_pager_freespace(prev_object, 1750 next_pindex, next_size); 1751 } 1752 1753 /* 1754 * Extend the object if necessary. 1755 */ 1756 if (next_pindex + next_size > prev_object->size) 1757 prev_object->size = next_pindex + next_size; 1758 1759 return (TRUE); 1760 } 1761 1762 void 1763 vm_object_set_writeable_dirty(vm_object_t object) 1764 { 1765 struct vnode *vp; 1766 1767 vm_object_set_flag(object, OBJ_WRITEABLE|OBJ_MIGHTBEDIRTY); 1768 if (object->type == OBJT_VNODE && 1769 (vp = (struct vnode *)object->handle) != NULL) { 1770 if ((vp->v_flag & VOBJDIRTY) == 0) { 1771 mtx_lock(&vp->v_interlock); 1772 vp->v_flag |= VOBJDIRTY; 1773 mtx_unlock(&vp->v_interlock); 1774 } 1775 } 1776 } 1777 1778 #include "opt_ddb.h" 1779 #ifdef DDB 1780 #include <sys/kernel.h> 1781 1782 #include <sys/cons.h> 1783 1784 #include <ddb/ddb.h> 1785 1786 static int 1787 _vm_object_in_map(vm_map_t map, vm_object_t object, vm_map_entry_t entry) 1788 { 1789 vm_map_t tmpm; 1790 vm_map_entry_t tmpe; 1791 vm_object_t obj; 1792 int entcount; 1793 1794 if (map == 0) 1795 return 0; 1796 1797 if (entry == 0) { 1798 tmpe = map->header.next; 1799 entcount = map->nentries; 1800 while (entcount-- && (tmpe != &map->header)) { 1801 if (_vm_object_in_map(map, object, tmpe)) { 1802 return 1; 1803 } 1804 tmpe = tmpe->next; 1805 } 1806 } else if (entry->eflags & MAP_ENTRY_IS_SUB_MAP) { 1807 tmpm = entry->object.sub_map; 1808 tmpe = tmpm->header.next; 1809 entcount = tmpm->nentries; 1810 while (entcount-- && tmpe != &tmpm->header) { 1811 if (_vm_object_in_map(tmpm, object, tmpe)) { 1812 return 1; 1813 } 1814 tmpe = tmpe->next; 1815 } 1816 } else if ((obj = entry->object.vm_object) != NULL) { 1817 for (; obj; obj = obj->backing_object) 1818 if (obj == object) { 1819 return 1; 1820 } 1821 } 1822 return 0; 1823 } 1824 1825 static int 1826 vm_object_in_map(vm_object_t object) 1827 { 1828 struct proc *p; 1829 1830 /* sx_slock(&allproc_lock); */ 1831 LIST_FOREACH(p, &allproc, p_list) { 1832 if (!p->p_vmspace /* || (p->p_flag & (P_SYSTEM|P_WEXIT)) */) 1833 continue; 1834 if (_vm_object_in_map(&p->p_vmspace->vm_map, object, 0)) { 1835 /* sx_sunlock(&allproc_lock); */ 1836 return 1; 1837 } 1838 } 1839 /* sx_sunlock(&allproc_lock); */ 1840 if (_vm_object_in_map(kernel_map, object, 0)) 1841 return 1; 1842 if (_vm_object_in_map(kmem_map, object, 0)) 1843 return 1; 1844 if (_vm_object_in_map(pager_map, object, 0)) 1845 return 1; 1846 if (_vm_object_in_map(buffer_map, object, 0)) 1847 return 1; 1848 return 0; 1849 } 1850 1851 DB_SHOW_COMMAND(vmochk, vm_object_check) 1852 { 1853 vm_object_t object; 1854 1855 /* 1856 * make sure that internal objs are in a map somewhere 1857 * and none have zero ref counts. 1858 */ 1859 TAILQ_FOREACH(object, &vm_object_list, object_list) { 1860 if (object->handle == NULL && 1861 (object->type == OBJT_DEFAULT || object->type == OBJT_SWAP)) { 1862 if (object->ref_count == 0) { 1863 db_printf("vmochk: internal obj has zero ref count: %ld\n", 1864 (long)object->size); 1865 } 1866 if (!vm_object_in_map(object)) { 1867 db_printf( 1868 "vmochk: internal obj is not in a map: " 1869 "ref: %d, size: %lu: 0x%lx, backing_object: %p\n", 1870 object->ref_count, (u_long)object->size, 1871 (u_long)object->size, 1872 (void *)object->backing_object); 1873 } 1874 } 1875 } 1876 } 1877 1878 /* 1879 * vm_object_print: [ debug ] 1880 */ 1881 DB_SHOW_COMMAND(object, vm_object_print_static) 1882 { 1883 /* XXX convert args. */ 1884 vm_object_t object = (vm_object_t)addr; 1885 boolean_t full = have_addr; 1886 1887 vm_page_t p; 1888 1889 /* XXX count is an (unused) arg. Avoid shadowing it. */ 1890 #define count was_count 1891 1892 int count; 1893 1894 if (object == NULL) 1895 return; 1896 1897 db_iprintf( 1898 "Object %p: type=%d, size=0x%lx, res=%d, ref=%d, flags=0x%x\n", 1899 object, (int)object->type, (u_long)object->size, 1900 object->resident_page_count, object->ref_count, object->flags); 1901 /* 1902 * XXX no %qd in kernel. Truncate object->backing_object_offset. 1903 */ 1904 db_iprintf(" sref=%d, backing_object(%d)=(%p)+0x%lx\n", 1905 object->shadow_count, 1906 object->backing_object ? object->backing_object->ref_count : 0, 1907 object->backing_object, (long)object->backing_object_offset); 1908 1909 if (!full) 1910 return; 1911 1912 db_indent += 2; 1913 count = 0; 1914 TAILQ_FOREACH(p, &object->memq, listq) { 1915 if (count == 0) 1916 db_iprintf("memory:="); 1917 else if (count == 6) { 1918 db_printf("\n"); 1919 db_iprintf(" ..."); 1920 count = 0; 1921 } else 1922 db_printf(","); 1923 count++; 1924 1925 db_printf("(off=0x%lx,page=0x%lx)", 1926 (u_long) p->pindex, (u_long) VM_PAGE_TO_PHYS(p)); 1927 } 1928 if (count != 0) 1929 db_printf("\n"); 1930 db_indent -= 2; 1931 } 1932 1933 /* XXX. */ 1934 #undef count 1935 1936 /* XXX need this non-static entry for calling from vm_map_print. */ 1937 void 1938 vm_object_print( 1939 /* db_expr_t */ long addr, 1940 boolean_t have_addr, 1941 /* db_expr_t */ long count, 1942 char *modif) 1943 { 1944 vm_object_print_static(addr, have_addr, count, modif); 1945 } 1946 1947 DB_SHOW_COMMAND(vmopag, vm_object_print_pages) 1948 { 1949 vm_object_t object; 1950 int nl = 0; 1951 int c; 1952 1953 TAILQ_FOREACH(object, &vm_object_list, object_list) { 1954 vm_pindex_t idx, fidx; 1955 vm_pindex_t osize; 1956 vm_offset_t pa = -1, padiff; 1957 int rcount; 1958 vm_page_t m; 1959 1960 db_printf("new object: %p\n", (void *)object); 1961 if (nl > 18) { 1962 c = cngetc(); 1963 if (c != ' ') 1964 return; 1965 nl = 0; 1966 } 1967 nl++; 1968 rcount = 0; 1969 fidx = 0; 1970 osize = object->size; 1971 if (osize > 128) 1972 osize = 128; 1973 for (idx = 0; idx < osize; idx++) { 1974 m = vm_page_lookup(object, idx); 1975 if (m == NULL) { 1976 if (rcount) { 1977 db_printf(" index(%ld)run(%d)pa(0x%lx)\n", 1978 (long)fidx, rcount, (long)pa); 1979 if (nl > 18) { 1980 c = cngetc(); 1981 if (c != ' ') 1982 return; 1983 nl = 0; 1984 } 1985 nl++; 1986 rcount = 0; 1987 } 1988 continue; 1989 } 1990 1991 1992 if (rcount && 1993 (VM_PAGE_TO_PHYS(m) == pa + rcount * PAGE_SIZE)) { 1994 ++rcount; 1995 continue; 1996 } 1997 if (rcount) { 1998 padiff = pa + rcount * PAGE_SIZE - VM_PAGE_TO_PHYS(m); 1999 padiff >>= PAGE_SHIFT; 2000 padiff &= PQ_L2_MASK; 2001 if (padiff == 0) { 2002 pa = VM_PAGE_TO_PHYS(m) - rcount * PAGE_SIZE; 2003 ++rcount; 2004 continue; 2005 } 2006 db_printf(" index(%ld)run(%d)pa(0x%lx)", 2007 (long)fidx, rcount, (long)pa); 2008 db_printf("pd(%ld)\n", (long)padiff); 2009 if (nl > 18) { 2010 c = cngetc(); 2011 if (c != ' ') 2012 return; 2013 nl = 0; 2014 } 2015 nl++; 2016 } 2017 fidx = idx; 2018 pa = VM_PAGE_TO_PHYS(m); 2019 rcount = 1; 2020 } 2021 if (rcount) { 2022 db_printf(" index(%ld)run(%d)pa(0x%lx)\n", 2023 (long)fidx, rcount, (long)pa); 2024 if (nl > 18) { 2025 c = cngetc(); 2026 if (c != ' ') 2027 return; 2028 nl = 0; 2029 } 2030 nl++; 2031 } 2032 } 2033 } 2034 #endif /* DDB */ 2035