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/stdint.h> 82 #include <sys/vnode.h> 83 #include <sys/vmmeter.h> 84 #include <sys/sx.h> 85 86 #include <vm/vm.h> 87 #include <vm/vm_param.h> 88 #include <vm/pmap.h> 89 #include <vm/vm_map.h> 90 #include <vm/vm_object.h> 91 #include <vm/vm_page.h> 92 #include <vm/vm_pageout.h> 93 #include <vm/vm_pager.h> 94 #include <vm/swap_pager.h> 95 #include <vm/vm_kern.h> 96 #include <vm/vm_extern.h> 97 #include <vm/uma.h> 98 99 #define EASY_SCAN_FACTOR 8 100 101 #define MSYNC_FLUSH_HARDSEQ 0x01 102 #define MSYNC_FLUSH_SOFTSEQ 0x02 103 104 /* 105 * msync / VM object flushing optimizations 106 */ 107 static int msync_flush_flags = MSYNC_FLUSH_HARDSEQ | MSYNC_FLUSH_SOFTSEQ; 108 SYSCTL_INT(_vm, OID_AUTO, msync_flush_flags, 109 CTLFLAG_RW, &msync_flush_flags, 0, ""); 110 111 static void vm_object_qcollapse(vm_object_t object); 112 static int vm_object_page_collect_flush(vm_object_t object, vm_page_t p, int curgeneration, int pagerflags); 113 114 /* 115 * Virtual memory objects maintain the actual data 116 * associated with allocated virtual memory. A given 117 * page of memory exists within exactly one object. 118 * 119 * An object is only deallocated when all "references" 120 * are given up. Only one "reference" to a given 121 * region of an object should be writeable. 122 * 123 * Associated with each object is a list of all resident 124 * memory pages belonging to that object; this list is 125 * maintained by the "vm_page" module, and locked by the object's 126 * lock. 127 * 128 * Each object also records a "pager" routine which is 129 * used to retrieve (and store) pages to the proper backing 130 * storage. In addition, objects may be backed by other 131 * objects from which they were virtual-copied. 132 * 133 * The only items within the object structure which are 134 * modified after time of creation are: 135 * reference count locked by object's lock 136 * pager routine locked by object's lock 137 * 138 */ 139 140 struct object_q vm_object_list; 141 struct mtx vm_object_list_mtx; /* lock for object list and count */ 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 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 bzero(&object->mtx, sizeof(object->mtx)); 184 185 /* These are true for any object that has been freed */ 186 object->paging_in_progress = 0; 187 object->resident_page_count = 0; 188 object->shadow_count = 0; 189 } 190 191 void 192 _vm_object_allocate(objtype_t type, vm_pindex_t size, vm_object_t object) 193 { 194 int incr; 195 196 mtx_init(&object->mtx, "vm object", NULL, MTX_DEF); 197 198 TAILQ_INIT(&object->memq); 199 TAILQ_INIT(&object->shadow_head); 200 201 object->root = NULL; 202 object->type = type; 203 object->size = size; 204 object->ref_count = 1; 205 object->flags = 0; 206 if ((object->type == OBJT_DEFAULT) || (object->type == OBJT_SWAP)) 207 vm_object_set_flag(object, OBJ_ONEMAPPING); 208 if (size > (PQ_L2_SIZE / 3 + PQ_PRIME1)) 209 incr = PQ_L2_SIZE / 3 + PQ_PRIME1; 210 else 211 incr = size; 212 do 213 object->pg_color = next_index; 214 while (!atomic_cmpset_int(&next_index, object->pg_color, 215 (object->pg_color + incr) & PQ_L2_MASK)); 216 object->handle = NULL; 217 object->backing_object = NULL; 218 object->backing_object_offset = (vm_ooffset_t) 0; 219 220 atomic_add_int(&object->generation, 1); 221 222 mtx_lock(&vm_object_list_mtx); 223 TAILQ_INSERT_TAIL(&vm_object_list, object, object_list); 224 mtx_unlock(&vm_object_list_mtx); 225 } 226 227 /* 228 * vm_object_init: 229 * 230 * Initialize the VM objects module. 231 */ 232 void 233 vm_object_init(void) 234 { 235 TAILQ_INIT(&vm_object_list); 236 mtx_init(&vm_object_list_mtx, "vm object_list", NULL, MTX_DEF); 237 238 kernel_object = &kernel_object_store; 239 _vm_object_allocate(OBJT_DEFAULT, OFF_TO_IDX(VM_MAX_KERNEL_ADDRESS - VM_MIN_KERNEL_ADDRESS), 240 kernel_object); 241 242 kmem_object = &kmem_object_store; 243 _vm_object_allocate(OBJT_DEFAULT, OFF_TO_IDX(VM_MAX_KERNEL_ADDRESS - VM_MIN_KERNEL_ADDRESS), 244 kmem_object); 245 obj_zone = uma_zcreate("VM OBJECT", sizeof (struct vm_object), NULL, 246 #ifdef INVARIANTS 247 vm_object_zdtor, 248 #else 249 NULL, 250 #endif 251 vm_object_zinit, NULL, UMA_ALIGN_PTR, UMA_ZONE_NOFREE); 252 uma_prealloc(obj_zone, VM_OBJECTS_INIT); 253 } 254 255 void 256 vm_object_set_flag(vm_object_t object, u_short bits) 257 { 258 object->flags |= bits; 259 } 260 261 void 262 vm_object_clear_flag(vm_object_t object, u_short bits) 263 { 264 265 mtx_assert(object == kmem_object ? &object->mtx : &Giant, MA_OWNED); 266 object->flags &= ~bits; 267 } 268 269 void 270 vm_object_pip_add(vm_object_t object, short i) 271 { 272 GIANT_REQUIRED; 273 object->paging_in_progress += i; 274 } 275 276 void 277 vm_object_pip_subtract(vm_object_t object, short i) 278 { 279 GIANT_REQUIRED; 280 object->paging_in_progress -= i; 281 } 282 283 void 284 vm_object_pip_wakeup(vm_object_t object) 285 { 286 GIANT_REQUIRED; 287 object->paging_in_progress--; 288 if ((object->flags & OBJ_PIPWNT) && object->paging_in_progress == 0) { 289 vm_object_clear_flag(object, OBJ_PIPWNT); 290 wakeup(object); 291 } 292 } 293 294 void 295 vm_object_pip_wakeupn(vm_object_t object, short i) 296 { 297 GIANT_REQUIRED; 298 if (i) 299 object->paging_in_progress -= i; 300 if ((object->flags & OBJ_PIPWNT) && object->paging_in_progress == 0) { 301 vm_object_clear_flag(object, OBJ_PIPWNT); 302 wakeup(object); 303 } 304 } 305 306 void 307 vm_object_pip_sleep(vm_object_t object, char *waitid) 308 { 309 GIANT_REQUIRED; 310 if (object->paging_in_progress) { 311 int s = splvm(); 312 if (object->paging_in_progress) { 313 vm_object_set_flag(object, OBJ_PIPWNT); 314 tsleep(object, PVM, waitid, 0); 315 } 316 splx(s); 317 } 318 } 319 320 void 321 vm_object_pip_wait(vm_object_t object, char *waitid) 322 { 323 GIANT_REQUIRED; 324 while (object->paging_in_progress) 325 vm_object_pip_sleep(object, waitid); 326 } 327 328 /* 329 * vm_object_allocate_wait 330 * 331 * Return a new object with the given size, and give the user the 332 * option of waiting for it to complete or failing if the needed 333 * memory isn't available. 334 */ 335 vm_object_t 336 vm_object_allocate_wait(objtype_t type, vm_pindex_t size, int flags) 337 { 338 vm_object_t result; 339 340 result = (vm_object_t) uma_zalloc(obj_zone, flags); 341 342 if (result != NULL) 343 _vm_object_allocate(type, size, result); 344 345 return (result); 346 } 347 348 /* 349 * vm_object_allocate: 350 * 351 * Returns a new object with the given size. 352 */ 353 vm_object_t 354 vm_object_allocate(objtype_t type, vm_pindex_t size) 355 { 356 return(vm_object_allocate_wait(type, size, M_WAITOK)); 357 } 358 359 360 /* 361 * vm_object_reference: 362 * 363 * Gets another reference to the given object. 364 */ 365 void 366 vm_object_reference(vm_object_t object) 367 { 368 if (object == NULL) 369 return; 370 371 vm_object_lock(object); 372 #if 0 373 /* object can be re-referenced during final cleaning */ 374 KASSERT(!(object->flags & OBJ_DEAD), 375 ("vm_object_reference: attempting to reference dead obj")); 376 #endif 377 378 object->ref_count++; 379 if (object->type == OBJT_VNODE) { 380 while (vget((struct vnode *) object->handle, LK_RETRY, curthread)) { 381 printf("vm_object_reference: delay in getting object\n"); 382 } 383 } 384 vm_object_unlock(object); 385 } 386 387 /* 388 * Handle deallocating an object of type OBJT_VNODE. 389 */ 390 void 391 vm_object_vndeallocate(vm_object_t object) 392 { 393 struct vnode *vp = (struct vnode *) object->handle; 394 395 GIANT_REQUIRED; 396 KASSERT(object->type == OBJT_VNODE, 397 ("vm_object_vndeallocate: not a vnode object")); 398 KASSERT(vp != NULL, ("vm_object_vndeallocate: missing vp")); 399 #ifdef INVARIANTS 400 if (object->ref_count == 0) { 401 vprint("vm_object_vndeallocate", vp); 402 panic("vm_object_vndeallocate: bad object reference count"); 403 } 404 #endif 405 406 object->ref_count--; 407 if (object->ref_count == 0) { 408 mp_fixme("Unlocked vflag access."); 409 vp->v_vflag &= ~VV_TEXT; 410 } 411 /* 412 * vrele may need a vop lock 413 */ 414 vrele(vp); 415 } 416 417 /* 418 * vm_object_deallocate: 419 * 420 * Release a reference to the specified object, 421 * gained either through a vm_object_allocate 422 * or a vm_object_reference call. When all references 423 * are gone, storage associated with this object 424 * may be relinquished. 425 * 426 * No object may be locked. 427 */ 428 void 429 vm_object_deallocate(vm_object_t object) 430 { 431 vm_object_t temp; 432 433 vm_object_lock(object); 434 while (object != NULL) { 435 436 if (object->type == OBJT_VNODE) { 437 vm_object_vndeallocate(object); 438 vm_object_unlock(object); 439 return; 440 } 441 442 KASSERT(object->ref_count != 0, 443 ("vm_object_deallocate: object deallocated too many times: %d", object->type)); 444 445 /* 446 * If the reference count goes to 0 we start calling 447 * vm_object_terminate() on the object chain. 448 * A ref count of 1 may be a special case depending on the 449 * shadow count being 0 or 1. 450 */ 451 object->ref_count--; 452 if (object->ref_count > 1) { 453 vm_object_unlock(object); 454 return; 455 } else if (object->ref_count == 1) { 456 if (object->shadow_count == 0) { 457 vm_object_set_flag(object, OBJ_ONEMAPPING); 458 } else if ((object->shadow_count == 1) && 459 (object->handle == NULL) && 460 (object->type == OBJT_DEFAULT || 461 object->type == OBJT_SWAP)) { 462 vm_object_t robject; 463 464 robject = TAILQ_FIRST(&object->shadow_head); 465 KASSERT(robject != NULL, 466 ("vm_object_deallocate: ref_count: %d, shadow_count: %d", 467 object->ref_count, 468 object->shadow_count)); 469 if ((robject->handle == NULL) && 470 (robject->type == OBJT_DEFAULT || 471 robject->type == OBJT_SWAP)) { 472 473 robject->ref_count++; 474 475 while ( 476 robject->paging_in_progress || 477 object->paging_in_progress 478 ) { 479 vm_object_pip_sleep(robject, "objde1"); 480 vm_object_pip_sleep(object, "objde2"); 481 } 482 483 if (robject->ref_count == 1) { 484 robject->ref_count--; 485 object = robject; 486 goto doterm; 487 } 488 489 object = robject; 490 vm_object_collapse(object); 491 continue; 492 } 493 } 494 vm_object_unlock(object); 495 return; 496 } 497 doterm: 498 temp = object->backing_object; 499 if (temp) { 500 TAILQ_REMOVE(&temp->shadow_head, object, shadow_list); 501 temp->shadow_count--; 502 temp->generation++; 503 object->backing_object = NULL; 504 } 505 /* 506 * Don't double-terminate, we could be in a termination 507 * recursion due to the terminate having to sync data 508 * to disk. 509 */ 510 if ((object->flags & OBJ_DEAD) == 0) 511 vm_object_terminate(object); 512 object = temp; 513 } 514 vm_object_unlock(object); 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 * Clean pages and flush buffers. 554 */ 555 vm_object_page_clean(object, 0, 0, OBJPC_SYNC); 556 557 vp = (struct vnode *) object->handle; 558 vinvalbuf(vp, V_SAVE, NOCRED, NULL, 0, 0); 559 } 560 561 KASSERT(object->ref_count == 0, 562 ("vm_object_terminate: object with references, ref_count=%d", 563 object->ref_count)); 564 565 /* 566 * Now free any remaining pages. For internal objects, this also 567 * removes them from paging queues. Don't free wired pages, just 568 * remove them from the object. 569 */ 570 s = splvm(); 571 vm_page_lock_queues(); 572 while ((p = TAILQ_FIRST(&object->memq)) != NULL) { 573 KASSERT(!p->busy && (p->flags & PG_BUSY) == 0, 574 ("vm_object_terminate: freeing busy page %p " 575 "p->busy = %d, p->flags %x\n", p, p->busy, p->flags)); 576 if (p->wire_count == 0) { 577 vm_page_busy(p); 578 vm_page_free(p); 579 cnt.v_pfree++; 580 } else { 581 vm_page_busy(p); 582 vm_page_remove(p); 583 } 584 } 585 vm_page_unlock_queues(); 586 splx(s); 587 588 /* 589 * Let the pager know object is dead. 590 */ 591 vm_pager_deallocate(object); 592 593 /* 594 * Remove the object from the global object list. 595 */ 596 mtx_lock(&vm_object_list_mtx); 597 TAILQ_REMOVE(&vm_object_list, object, object_list); 598 mtx_unlock(&vm_object_list_mtx); 599 600 mtx_destroy(&object->mtx); 601 wakeup(object); 602 603 /* 604 * Free the space for the object. 605 */ 606 uma_zfree(obj_zone, object); 607 } 608 609 /* 610 * vm_object_page_clean 611 * 612 * Clean all dirty pages in the specified range of object. Leaves page 613 * on whatever queue it is currently on. If NOSYNC is set then do not 614 * write out pages with PG_NOSYNC set (originally comes from MAP_NOSYNC), 615 * leaving the object dirty. 616 * 617 * When stuffing pages asynchronously, allow clustering. XXX we need a 618 * synchronous clustering mode implementation. 619 * 620 * Odd semantics: if start == end, we clean everything. 621 * 622 * The object must be locked. 623 */ 624 void 625 vm_object_page_clean(vm_object_t object, vm_pindex_t start, vm_pindex_t end, int flags) 626 { 627 vm_page_t p, np; 628 vm_pindex_t tstart, tend; 629 vm_pindex_t pi; 630 struct vnode *vp; 631 int clearobjflags; 632 int pagerflags; 633 int curgeneration; 634 635 GIANT_REQUIRED; 636 637 if (object->type != OBJT_VNODE || 638 (object->flags & OBJ_MIGHTBEDIRTY) == 0) 639 return; 640 641 pagerflags = (flags & (OBJPC_SYNC | OBJPC_INVAL)) ? VM_PAGER_PUT_SYNC : VM_PAGER_CLUSTER_OK; 642 pagerflags |= (flags & OBJPC_INVAL) ? VM_PAGER_PUT_INVAL : 0; 643 644 vp = object->handle; 645 646 vm_object_set_flag(object, OBJ_CLEANING); 647 648 tstart = start; 649 if (end == 0) { 650 tend = object->size; 651 } else { 652 tend = end; 653 } 654 655 vm_page_lock_queues(); 656 /* 657 * If the caller is smart and only msync()s a range he knows is 658 * dirty, we may be able to avoid an object scan. This results in 659 * a phenominal improvement in performance. We cannot do this 660 * as a matter of course because the object may be huge - e.g. 661 * the size might be in the gigabytes or terrabytes. 662 */ 663 if (msync_flush_flags & MSYNC_FLUSH_HARDSEQ) { 664 vm_pindex_t tscan; 665 int scanlimit; 666 int scanreset; 667 668 scanreset = object->resident_page_count / EASY_SCAN_FACTOR; 669 if (scanreset < 16) 670 scanreset = 16; 671 pagerflags |= VM_PAGER_IGNORE_CLEANCHK; 672 673 scanlimit = scanreset; 674 tscan = tstart; 675 while (tscan < tend) { 676 curgeneration = object->generation; 677 p = vm_page_lookup(object, tscan); 678 if (p == NULL || p->valid == 0 || 679 (p->queue - p->pc) == PQ_CACHE) { 680 if (--scanlimit == 0) 681 break; 682 ++tscan; 683 continue; 684 } 685 vm_page_test_dirty(p); 686 if ((p->dirty & p->valid) == 0) { 687 if (--scanlimit == 0) 688 break; 689 ++tscan; 690 continue; 691 } 692 /* 693 * If we have been asked to skip nosync pages and 694 * this is a nosync page, we can't continue. 695 */ 696 if ((flags & OBJPC_NOSYNC) && (p->flags & PG_NOSYNC)) { 697 if (--scanlimit == 0) 698 break; 699 ++tscan; 700 continue; 701 } 702 scanlimit = scanreset; 703 704 /* 705 * This returns 0 if it was unable to busy the first 706 * page (i.e. had to sleep). 707 */ 708 tscan += vm_object_page_collect_flush(object, p, curgeneration, pagerflags); 709 } 710 711 /* 712 * If everything was dirty and we flushed it successfully, 713 * and the requested range is not the entire object, we 714 * don't have to mess with CLEANCHK or MIGHTBEDIRTY and can 715 * return immediately. 716 */ 717 if (tscan >= tend && (tstart || tend < object->size)) { 718 vm_page_unlock_queues(); 719 vm_object_clear_flag(object, OBJ_CLEANING); 720 return; 721 } 722 pagerflags &= ~VM_PAGER_IGNORE_CLEANCHK; 723 } 724 725 /* 726 * Generally set CLEANCHK interlock and make the page read-only so 727 * we can then clear the object flags. 728 * 729 * However, if this is a nosync mmap then the object is likely to 730 * stay dirty so do not mess with the page and do not clear the 731 * object flags. 732 */ 733 clearobjflags = 1; 734 TAILQ_FOREACH(p, &object->memq, listq) { 735 vm_page_flag_set(p, PG_CLEANCHK); 736 if ((flags & OBJPC_NOSYNC) && (p->flags & PG_NOSYNC)) 737 clearobjflags = 0; 738 else 739 pmap_page_protect(p, VM_PROT_READ); 740 } 741 742 if (clearobjflags && (tstart == 0) && (tend == object->size)) { 743 struct vnode *vp; 744 745 vm_object_clear_flag(object, OBJ_WRITEABLE|OBJ_MIGHTBEDIRTY); 746 if (object->type == OBJT_VNODE && 747 (vp = (struct vnode *)object->handle) != NULL) { 748 VI_LOCK(vp); 749 if (vp->v_iflag & VI_OBJDIRTY) 750 vp->v_iflag &= ~VI_OBJDIRTY; 751 VI_UNLOCK(vp); 752 } 753 } 754 755 rescan: 756 curgeneration = object->generation; 757 758 for (p = TAILQ_FIRST(&object->memq); p; p = np) { 759 int n; 760 761 np = TAILQ_NEXT(p, listq); 762 763 again: 764 pi = p->pindex; 765 if (((p->flags & PG_CLEANCHK) == 0) || 766 (pi < tstart) || (pi >= tend) || 767 (p->valid == 0) || 768 ((p->queue - p->pc) == PQ_CACHE)) { 769 vm_page_flag_clear(p, PG_CLEANCHK); 770 continue; 771 } 772 773 vm_page_test_dirty(p); 774 if ((p->dirty & p->valid) == 0) { 775 vm_page_flag_clear(p, PG_CLEANCHK); 776 continue; 777 } 778 779 /* 780 * If we have been asked to skip nosync pages and this is a 781 * nosync page, skip it. Note that the object flags were 782 * not cleared in this case so we do not have to set them. 783 */ 784 if ((flags & OBJPC_NOSYNC) && (p->flags & PG_NOSYNC)) { 785 vm_page_flag_clear(p, PG_CLEANCHK); 786 continue; 787 } 788 789 n = vm_object_page_collect_flush(object, p, 790 curgeneration, pagerflags); 791 if (n == 0) 792 goto rescan; 793 794 if (object->generation != curgeneration) 795 goto rescan; 796 797 /* 798 * Try to optimize the next page. If we can't we pick up 799 * our (random) scan where we left off. 800 */ 801 if (msync_flush_flags & MSYNC_FLUSH_SOFTSEQ) { 802 if ((p = vm_page_lookup(object, pi + n)) != NULL) 803 goto again; 804 } 805 } 806 vm_page_unlock_queues(); 807 #if 0 808 VOP_FSYNC(vp, NULL, (pagerflags & VM_PAGER_PUT_SYNC)?MNT_WAIT:0, curproc); 809 #endif 810 811 vm_object_clear_flag(object, OBJ_CLEANING); 812 return; 813 } 814 815 static int 816 vm_object_page_collect_flush(vm_object_t object, vm_page_t p, int curgeneration, int pagerflags) 817 { 818 int runlen; 819 int s; 820 int maxf; 821 int chkb; 822 int maxb; 823 int i; 824 vm_pindex_t pi; 825 vm_page_t maf[vm_pageout_page_count]; 826 vm_page_t mab[vm_pageout_page_count]; 827 vm_page_t ma[vm_pageout_page_count]; 828 829 s = splvm(); 830 mtx_assert(&vm_page_queue_mtx, MA_OWNED); 831 pi = p->pindex; 832 while (vm_page_sleep_if_busy(p, TRUE, "vpcwai")) { 833 vm_page_lock_queues(); 834 if (object->generation != curgeneration) { 835 splx(s); 836 return(0); 837 } 838 } 839 maxf = 0; 840 for(i = 1; i < vm_pageout_page_count; i++) { 841 vm_page_t tp; 842 843 if ((tp = vm_page_lookup(object, pi + i)) != NULL) { 844 if ((tp->flags & PG_BUSY) || 845 ((pagerflags & VM_PAGER_IGNORE_CLEANCHK) == 0 && 846 (tp->flags & PG_CLEANCHK) == 0) || 847 (tp->busy != 0)) 848 break; 849 if((tp->queue - tp->pc) == PQ_CACHE) { 850 vm_page_flag_clear(tp, PG_CLEANCHK); 851 break; 852 } 853 vm_page_test_dirty(tp); 854 if ((tp->dirty & tp->valid) == 0) { 855 vm_page_flag_clear(tp, PG_CLEANCHK); 856 break; 857 } 858 maf[ i - 1 ] = tp; 859 maxf++; 860 continue; 861 } 862 break; 863 } 864 865 maxb = 0; 866 chkb = vm_pageout_page_count - maxf; 867 if (chkb) { 868 for(i = 1; i < chkb;i++) { 869 vm_page_t tp; 870 871 if ((tp = vm_page_lookup(object, pi - i)) != NULL) { 872 if ((tp->flags & PG_BUSY) || 873 ((pagerflags & VM_PAGER_IGNORE_CLEANCHK) == 0 && 874 (tp->flags & PG_CLEANCHK) == 0) || 875 (tp->busy != 0)) 876 break; 877 if ((tp->queue - tp->pc) == PQ_CACHE) { 878 vm_page_flag_clear(tp, PG_CLEANCHK); 879 break; 880 } 881 vm_page_test_dirty(tp); 882 if ((tp->dirty & tp->valid) == 0) { 883 vm_page_flag_clear(tp, PG_CLEANCHK); 884 break; 885 } 886 mab[ i - 1 ] = tp; 887 maxb++; 888 continue; 889 } 890 break; 891 } 892 } 893 894 for(i = 0; i < maxb; i++) { 895 int index = (maxb - i) - 1; 896 ma[index] = mab[i]; 897 vm_page_flag_clear(ma[index], PG_CLEANCHK); 898 } 899 vm_page_flag_clear(p, PG_CLEANCHK); 900 ma[maxb] = p; 901 for(i = 0; i < maxf; i++) { 902 int index = (maxb + i) + 1; 903 ma[index] = maf[i]; 904 vm_page_flag_clear(ma[index], PG_CLEANCHK); 905 } 906 runlen = maxb + maxf + 1; 907 908 splx(s); 909 vm_pageout_flush(ma, runlen, pagerflags); 910 for (i = 0; i < runlen; i++) { 911 if (ma[i]->valid & ma[i]->dirty) { 912 pmap_page_protect(ma[i], VM_PROT_READ); 913 vm_page_flag_set(ma[i], PG_CLEANCHK); 914 915 /* 916 * maxf will end up being the actual number of pages 917 * we wrote out contiguously, non-inclusive of the 918 * first page. We do not count look-behind pages. 919 */ 920 if (i >= maxb + 1 && (maxf > i - maxb - 1)) 921 maxf = i - maxb - 1; 922 } 923 } 924 return(maxf + 1); 925 } 926 927 /* 928 * vm_object_madvise: 929 * 930 * Implements the madvise function at the object/page level. 931 * 932 * MADV_WILLNEED (any object) 933 * 934 * Activate the specified pages if they are resident. 935 * 936 * MADV_DONTNEED (any object) 937 * 938 * Deactivate the specified pages if they are resident. 939 * 940 * MADV_FREE (OBJT_DEFAULT/OBJT_SWAP objects, 941 * OBJ_ONEMAPPING only) 942 * 943 * Deactivate and clean the specified pages if they are 944 * resident. This permits the process to reuse the pages 945 * without faulting or the kernel to reclaim the pages 946 * without I/O. 947 */ 948 void 949 vm_object_madvise(vm_object_t object, vm_pindex_t pindex, int count, int advise) 950 { 951 vm_pindex_t end, tpindex; 952 vm_object_t tobject; 953 vm_page_t m; 954 955 if (object == NULL) 956 return; 957 958 vm_object_lock(object); 959 960 end = pindex + count; 961 962 /* 963 * Locate and adjust resident pages 964 */ 965 for (; pindex < end; pindex += 1) { 966 relookup: 967 tobject = object; 968 tpindex = pindex; 969 shadowlookup: 970 /* 971 * MADV_FREE only operates on OBJT_DEFAULT or OBJT_SWAP pages 972 * and those pages must be OBJ_ONEMAPPING. 973 */ 974 if (advise == MADV_FREE) { 975 if ((tobject->type != OBJT_DEFAULT && 976 tobject->type != OBJT_SWAP) || 977 (tobject->flags & OBJ_ONEMAPPING) == 0) { 978 continue; 979 } 980 } 981 982 m = vm_page_lookup(tobject, tpindex); 983 984 if (m == NULL) { 985 /* 986 * There may be swap even if there is no backing page 987 */ 988 if (advise == MADV_FREE && tobject->type == OBJT_SWAP) 989 swap_pager_freespace(tobject, tpindex, 1); 990 991 /* 992 * next object 993 */ 994 tobject = tobject->backing_object; 995 if (tobject == NULL) 996 continue; 997 tpindex += OFF_TO_IDX(tobject->backing_object_offset); 998 goto shadowlookup; 999 } 1000 1001 /* 1002 * If the page is busy or not in a normal active state, 1003 * we skip it. If the page is not managed there are no 1004 * page queues to mess with. Things can break if we mess 1005 * with pages in any of the below states. 1006 */ 1007 vm_page_lock_queues(); 1008 if (m->hold_count || 1009 m->wire_count || 1010 (m->flags & PG_UNMANAGED) || 1011 m->valid != VM_PAGE_BITS_ALL) { 1012 vm_page_unlock_queues(); 1013 continue; 1014 } 1015 if (vm_page_sleep_if_busy(m, TRUE, "madvpo")) 1016 goto relookup; 1017 if (advise == MADV_WILLNEED) { 1018 vm_page_activate(m); 1019 } else if (advise == MADV_DONTNEED) { 1020 vm_page_dontneed(m); 1021 } else if (advise == MADV_FREE) { 1022 /* 1023 * Mark the page clean. This will allow the page 1024 * to be freed up by the system. However, such pages 1025 * are often reused quickly by malloc()/free() 1026 * so we do not do anything that would cause 1027 * a page fault if we can help it. 1028 * 1029 * Specifically, we do not try to actually free 1030 * the page now nor do we try to put it in the 1031 * cache (which would cause a page fault on reuse). 1032 * 1033 * But we do make the page is freeable as we 1034 * can without actually taking the step of unmapping 1035 * it. 1036 */ 1037 pmap_clear_modify(m); 1038 m->dirty = 0; 1039 m->act_count = 0; 1040 vm_page_dontneed(m); 1041 } 1042 vm_page_unlock_queues(); 1043 if (advise == MADV_FREE && tobject->type == OBJT_SWAP) 1044 swap_pager_freespace(tobject, tpindex, 1); 1045 } 1046 vm_object_unlock(object); 1047 } 1048 1049 /* 1050 * vm_object_shadow: 1051 * 1052 * Create a new object which is backed by the 1053 * specified existing object range. The source 1054 * object reference is deallocated. 1055 * 1056 * The new object and offset into that object 1057 * are returned in the source parameters. 1058 */ 1059 void 1060 vm_object_shadow( 1061 vm_object_t *object, /* IN/OUT */ 1062 vm_ooffset_t *offset, /* IN/OUT */ 1063 vm_size_t length) 1064 { 1065 vm_object_t source; 1066 vm_object_t result; 1067 1068 source = *object; 1069 1070 vm_object_lock(source); 1071 /* 1072 * Don't create the new object if the old object isn't shared. 1073 */ 1074 if (source != NULL && 1075 source->ref_count == 1 && 1076 source->handle == NULL && 1077 (source->type == OBJT_DEFAULT || 1078 source->type == OBJT_SWAP)) { 1079 vm_object_unlock(source); 1080 return; 1081 } 1082 1083 /* 1084 * Allocate a new object with the given length 1085 */ 1086 result = vm_object_allocate(OBJT_DEFAULT, length); 1087 KASSERT(result != NULL, ("vm_object_shadow: no object for shadowing")); 1088 1089 /* 1090 * The new object shadows the source object, adding a reference to it. 1091 * Our caller changes his reference to point to the new object, 1092 * removing a reference to the source object. Net result: no change 1093 * of reference count. 1094 * 1095 * Try to optimize the result object's page color when shadowing 1096 * in order to maintain page coloring consistency in the combined 1097 * shadowed object. 1098 */ 1099 result->backing_object = source; 1100 if (source) { 1101 TAILQ_INSERT_TAIL(&source->shadow_head, result, shadow_list); 1102 source->shadow_count++; 1103 source->generation++; 1104 if (length < source->size) 1105 length = source->size; 1106 if (length > PQ_L2_SIZE / 3 + PQ_PRIME1 || 1107 source->generation > 1) 1108 length = PQ_L2_SIZE / 3 + PQ_PRIME1; 1109 result->pg_color = (source->pg_color + 1110 length * source->generation) & PQ_L2_MASK; 1111 next_index = (result->pg_color + PQ_L2_SIZE / 3 + PQ_PRIME1) & 1112 PQ_L2_MASK; 1113 } 1114 1115 /* 1116 * Store the offset into the source object, and fix up the offset into 1117 * the new object. 1118 */ 1119 result->backing_object_offset = *offset; 1120 1121 /* 1122 * Return the new things 1123 */ 1124 *offset = 0; 1125 *object = result; 1126 1127 vm_object_unlock(source); 1128 } 1129 1130 /* 1131 * vm_object_split: 1132 * 1133 * Split the pages in a map entry into a new object. This affords 1134 * easier removal of unused pages, and keeps object inheritance from 1135 * being a negative impact on memory usage. 1136 */ 1137 void 1138 vm_object_split(vm_map_entry_t entry) 1139 { 1140 vm_page_t m; 1141 vm_object_t orig_object, new_object, source; 1142 vm_offset_t s, e; 1143 vm_pindex_t offidxstart, offidxend; 1144 vm_size_t idx, size; 1145 vm_ooffset_t offset; 1146 1147 GIANT_REQUIRED; 1148 1149 orig_object = entry->object.vm_object; 1150 if (orig_object->type != OBJT_DEFAULT && orig_object->type != OBJT_SWAP) 1151 return; 1152 if (orig_object->ref_count <= 1) 1153 return; 1154 1155 offset = entry->offset; 1156 s = entry->start; 1157 e = entry->end; 1158 1159 offidxstart = OFF_TO_IDX(offset); 1160 offidxend = offidxstart + OFF_TO_IDX(e - s); 1161 size = offidxend - offidxstart; 1162 1163 new_object = vm_pager_allocate(orig_object->type, 1164 NULL, IDX_TO_OFF(size), VM_PROT_ALL, 0LL); 1165 if (new_object == NULL) 1166 return; 1167 1168 source = orig_object->backing_object; 1169 if (source != NULL) { 1170 vm_object_reference(source); /* Referenced by new_object */ 1171 TAILQ_INSERT_TAIL(&source->shadow_head, 1172 new_object, shadow_list); 1173 vm_object_clear_flag(source, OBJ_ONEMAPPING); 1174 new_object->backing_object_offset = 1175 orig_object->backing_object_offset + offset; 1176 new_object->backing_object = source; 1177 source->shadow_count++; 1178 source->generation++; 1179 } 1180 for (idx = 0; idx < size; idx++) { 1181 retry: 1182 m = vm_page_lookup(orig_object, offidxstart + idx); 1183 if (m == NULL) 1184 continue; 1185 1186 /* 1187 * We must wait for pending I/O to complete before we can 1188 * rename the page. 1189 * 1190 * We do not have to VM_PROT_NONE the page as mappings should 1191 * not be changed by this operation. 1192 */ 1193 vm_page_lock_queues(); 1194 if (vm_page_sleep_if_busy(m, TRUE, "spltwt")) 1195 goto retry; 1196 1197 vm_page_busy(m); 1198 vm_page_rename(m, new_object, idx); 1199 /* page automatically made dirty by rename and cache handled */ 1200 vm_page_busy(m); 1201 vm_page_unlock_queues(); 1202 } 1203 if (orig_object->type == OBJT_SWAP) { 1204 vm_object_pip_add(orig_object, 1); 1205 /* 1206 * copy orig_object pages into new_object 1207 * and destroy unneeded pages in 1208 * shadow object. 1209 */ 1210 swap_pager_copy(orig_object, new_object, offidxstart, 0); 1211 vm_object_pip_wakeup(orig_object); 1212 } 1213 vm_page_lock_queues(); 1214 TAILQ_FOREACH(m, &new_object->memq, listq) 1215 vm_page_wakeup(m); 1216 vm_page_unlock_queues(); 1217 entry->object.vm_object = new_object; 1218 entry->offset = 0LL; 1219 vm_object_deallocate(orig_object); 1220 } 1221 1222 #define OBSC_TEST_ALL_SHADOWED 0x0001 1223 #define OBSC_COLLAPSE_NOWAIT 0x0002 1224 #define OBSC_COLLAPSE_WAIT 0x0004 1225 1226 static __inline int 1227 vm_object_backing_scan(vm_object_t object, int op) 1228 { 1229 int s; 1230 int r = 1; 1231 vm_page_t p; 1232 vm_object_t backing_object; 1233 vm_pindex_t backing_offset_index; 1234 1235 s = splvm(); 1236 GIANT_REQUIRED; 1237 1238 backing_object = object->backing_object; 1239 backing_offset_index = OFF_TO_IDX(object->backing_object_offset); 1240 1241 /* 1242 * Initial conditions 1243 */ 1244 if (op & OBSC_TEST_ALL_SHADOWED) { 1245 /* 1246 * We do not want to have to test for the existence of 1247 * swap pages in the backing object. XXX but with the 1248 * new swapper this would be pretty easy to do. 1249 * 1250 * XXX what about anonymous MAP_SHARED memory that hasn't 1251 * been ZFOD faulted yet? If we do not test for this, the 1252 * shadow test may succeed! XXX 1253 */ 1254 if (backing_object->type != OBJT_DEFAULT) { 1255 splx(s); 1256 return (0); 1257 } 1258 } 1259 if (op & OBSC_COLLAPSE_WAIT) { 1260 vm_object_set_flag(backing_object, OBJ_DEAD); 1261 } 1262 1263 /* 1264 * Our scan 1265 */ 1266 p = TAILQ_FIRST(&backing_object->memq); 1267 while (p) { 1268 vm_page_t next = TAILQ_NEXT(p, listq); 1269 vm_pindex_t new_pindex = p->pindex - backing_offset_index; 1270 1271 if (op & OBSC_TEST_ALL_SHADOWED) { 1272 vm_page_t pp; 1273 1274 /* 1275 * Ignore pages outside the parent object's range 1276 * and outside the parent object's mapping of the 1277 * backing object. 1278 * 1279 * note that we do not busy the backing object's 1280 * page. 1281 */ 1282 if ( 1283 p->pindex < backing_offset_index || 1284 new_pindex >= object->size 1285 ) { 1286 p = next; 1287 continue; 1288 } 1289 1290 /* 1291 * See if the parent has the page or if the parent's 1292 * object pager has the page. If the parent has the 1293 * page but the page is not valid, the parent's 1294 * object pager must have the page. 1295 * 1296 * If this fails, the parent does not completely shadow 1297 * the object and we might as well give up now. 1298 */ 1299 1300 pp = vm_page_lookup(object, new_pindex); 1301 if ( 1302 (pp == NULL || pp->valid == 0) && 1303 !vm_pager_has_page(object, new_pindex, NULL, NULL) 1304 ) { 1305 r = 0; 1306 break; 1307 } 1308 } 1309 1310 /* 1311 * Check for busy page 1312 */ 1313 if (op & (OBSC_COLLAPSE_WAIT | OBSC_COLLAPSE_NOWAIT)) { 1314 vm_page_t pp; 1315 1316 vm_page_lock_queues(); 1317 if (op & OBSC_COLLAPSE_NOWAIT) { 1318 if ((p->flags & PG_BUSY) || 1319 !p->valid || 1320 p->hold_count || 1321 p->wire_count || 1322 p->busy) { 1323 vm_page_unlock_queues(); 1324 p = next; 1325 continue; 1326 } 1327 } else if (op & OBSC_COLLAPSE_WAIT) { 1328 if (vm_page_sleep_if_busy(p, TRUE, "vmocol")) { 1329 /* 1330 * If we slept, anything could have 1331 * happened. Since the object is 1332 * marked dead, the backing offset 1333 * should not have changed so we 1334 * just restart our scan. 1335 */ 1336 p = TAILQ_FIRST(&backing_object->memq); 1337 continue; 1338 } 1339 } 1340 1341 /* 1342 * Busy the page 1343 */ 1344 vm_page_busy(p); 1345 vm_page_unlock_queues(); 1346 1347 KASSERT( 1348 p->object == backing_object, 1349 ("vm_object_qcollapse(): object mismatch") 1350 ); 1351 1352 /* 1353 * Destroy any associated swap 1354 */ 1355 if (backing_object->type == OBJT_SWAP) { 1356 swap_pager_freespace( 1357 backing_object, 1358 p->pindex, 1359 1 1360 ); 1361 } 1362 1363 if ( 1364 p->pindex < backing_offset_index || 1365 new_pindex >= object->size 1366 ) { 1367 /* 1368 * Page is out of the parent object's range, we 1369 * can simply destroy it. 1370 */ 1371 vm_page_lock_queues(); 1372 pmap_remove_all(p); 1373 vm_page_free(p); 1374 vm_page_unlock_queues(); 1375 p = next; 1376 continue; 1377 } 1378 1379 pp = vm_page_lookup(object, new_pindex); 1380 if ( 1381 pp != NULL || 1382 vm_pager_has_page(object, new_pindex, NULL, NULL) 1383 ) { 1384 /* 1385 * page already exists in parent OR swap exists 1386 * for this location in the parent. Destroy 1387 * the original page from the backing object. 1388 * 1389 * Leave the parent's page alone 1390 */ 1391 vm_page_lock_queues(); 1392 pmap_remove_all(p); 1393 vm_page_free(p); 1394 vm_page_unlock_queues(); 1395 p = next; 1396 continue; 1397 } 1398 1399 /* 1400 * Page does not exist in parent, rename the 1401 * page from the backing object to the main object. 1402 * 1403 * If the page was mapped to a process, it can remain 1404 * mapped through the rename. 1405 */ 1406 vm_page_lock_queues(); 1407 vm_page_rename(p, object, new_pindex); 1408 vm_page_unlock_queues(); 1409 /* page automatically made dirty by rename */ 1410 } 1411 p = next; 1412 } 1413 splx(s); 1414 return (r); 1415 } 1416 1417 1418 /* 1419 * this version of collapse allows the operation to occur earlier and 1420 * when paging_in_progress is true for an object... This is not a complete 1421 * operation, but should plug 99.9% of the rest of the leaks. 1422 */ 1423 static void 1424 vm_object_qcollapse(vm_object_t object) 1425 { 1426 vm_object_t backing_object = object->backing_object; 1427 1428 GIANT_REQUIRED; 1429 1430 if (backing_object->ref_count != 1) 1431 return; 1432 1433 backing_object->ref_count += 2; 1434 1435 vm_object_backing_scan(object, OBSC_COLLAPSE_NOWAIT); 1436 1437 backing_object->ref_count -= 2; 1438 } 1439 1440 /* 1441 * vm_object_collapse: 1442 * 1443 * Collapse an object with the object backing it. 1444 * Pages in the backing object are moved into the 1445 * parent, and the backing object is deallocated. 1446 */ 1447 void 1448 vm_object_collapse(vm_object_t object) 1449 { 1450 GIANT_REQUIRED; 1451 1452 while (TRUE) { 1453 vm_object_t backing_object; 1454 1455 /* 1456 * Verify that the conditions are right for collapse: 1457 * 1458 * The object exists and the backing object exists. 1459 */ 1460 if (object == NULL) 1461 break; 1462 1463 if ((backing_object = object->backing_object) == NULL) 1464 break; 1465 1466 /* 1467 * we check the backing object first, because it is most likely 1468 * not collapsable. 1469 */ 1470 if (backing_object->handle != NULL || 1471 (backing_object->type != OBJT_DEFAULT && 1472 backing_object->type != OBJT_SWAP) || 1473 (backing_object->flags & OBJ_DEAD) || 1474 object->handle != NULL || 1475 (object->type != OBJT_DEFAULT && 1476 object->type != OBJT_SWAP) || 1477 (object->flags & OBJ_DEAD)) { 1478 break; 1479 } 1480 1481 if ( 1482 object->paging_in_progress != 0 || 1483 backing_object->paging_in_progress != 0 1484 ) { 1485 vm_object_qcollapse(object); 1486 break; 1487 } 1488 1489 /* 1490 * We know that we can either collapse the backing object (if 1491 * the parent is the only reference to it) or (perhaps) have 1492 * the parent bypass the object if the parent happens to shadow 1493 * all the resident pages in the entire backing object. 1494 * 1495 * This is ignoring pager-backed pages such as swap pages. 1496 * vm_object_backing_scan fails the shadowing test in this 1497 * case. 1498 */ 1499 if (backing_object->ref_count == 1) { 1500 /* 1501 * If there is exactly one reference to the backing 1502 * object, we can collapse it into the parent. 1503 */ 1504 vm_object_backing_scan(object, OBSC_COLLAPSE_WAIT); 1505 1506 /* 1507 * Move the pager from backing_object to object. 1508 */ 1509 if (backing_object->type == OBJT_SWAP) { 1510 vm_object_pip_add(backing_object, 1); 1511 1512 /* 1513 * scrap the paging_offset junk and do a 1514 * discrete copy. This also removes major 1515 * assumptions about how the swap-pager 1516 * works from where it doesn't belong. The 1517 * new swapper is able to optimize the 1518 * destroy-source case. 1519 */ 1520 vm_object_pip_add(object, 1); 1521 swap_pager_copy( 1522 backing_object, 1523 object, 1524 OFF_TO_IDX(object->backing_object_offset), TRUE); 1525 vm_object_pip_wakeup(object); 1526 1527 vm_object_pip_wakeup(backing_object); 1528 } 1529 /* 1530 * Object now shadows whatever backing_object did. 1531 * Note that the reference to 1532 * backing_object->backing_object moves from within 1533 * backing_object to within object. 1534 */ 1535 TAILQ_REMOVE( 1536 &object->backing_object->shadow_head, 1537 object, 1538 shadow_list 1539 ); 1540 object->backing_object->shadow_count--; 1541 object->backing_object->generation++; 1542 if (backing_object->backing_object) { 1543 TAILQ_REMOVE( 1544 &backing_object->backing_object->shadow_head, 1545 backing_object, 1546 shadow_list 1547 ); 1548 backing_object->backing_object->shadow_count--; 1549 backing_object->backing_object->generation++; 1550 } 1551 object->backing_object = backing_object->backing_object; 1552 if (object->backing_object) { 1553 TAILQ_INSERT_TAIL( 1554 &object->backing_object->shadow_head, 1555 object, 1556 shadow_list 1557 ); 1558 object->backing_object->shadow_count++; 1559 object->backing_object->generation++; 1560 } 1561 1562 object->backing_object_offset += 1563 backing_object->backing_object_offset; 1564 1565 /* 1566 * Discard backing_object. 1567 * 1568 * Since the backing object has no pages, no pager left, 1569 * and no object references within it, all that is 1570 * necessary is to dispose of it. 1571 */ 1572 KASSERT(backing_object->ref_count == 1, ("backing_object %p was somehow re-referenced during collapse!", backing_object)); 1573 KASSERT(TAILQ_FIRST(&backing_object->memq) == NULL, ("backing_object %p somehow has left over pages during collapse!", backing_object)); 1574 1575 mtx_lock(&vm_object_list_mtx); 1576 TAILQ_REMOVE( 1577 &vm_object_list, 1578 backing_object, 1579 object_list 1580 ); 1581 mtx_unlock(&vm_object_list_mtx); 1582 1583 mtx_destroy(&backing_object->mtx); 1584 1585 uma_zfree(obj_zone, backing_object); 1586 1587 object_collapses++; 1588 } else { 1589 vm_object_t new_backing_object; 1590 1591 /* 1592 * If we do not entirely shadow the backing object, 1593 * there is nothing we can do so we give up. 1594 */ 1595 if (vm_object_backing_scan(object, OBSC_TEST_ALL_SHADOWED) == 0) { 1596 break; 1597 } 1598 1599 /* 1600 * Make the parent shadow the next object in the 1601 * chain. Deallocating backing_object will not remove 1602 * it, since its reference count is at least 2. 1603 */ 1604 TAILQ_REMOVE( 1605 &backing_object->shadow_head, 1606 object, 1607 shadow_list 1608 ); 1609 backing_object->shadow_count--; 1610 backing_object->generation++; 1611 1612 new_backing_object = backing_object->backing_object; 1613 if ((object->backing_object = new_backing_object) != NULL) { 1614 vm_object_reference(new_backing_object); 1615 TAILQ_INSERT_TAIL( 1616 &new_backing_object->shadow_head, 1617 object, 1618 shadow_list 1619 ); 1620 new_backing_object->shadow_count++; 1621 new_backing_object->generation++; 1622 object->backing_object_offset += 1623 backing_object->backing_object_offset; 1624 } 1625 1626 /* 1627 * Drop the reference count on backing_object. Since 1628 * its ref_count was at least 2, it will not vanish; 1629 * so we don't need to call vm_object_deallocate, but 1630 * we do anyway. 1631 */ 1632 vm_object_deallocate(backing_object); 1633 object_bypasses++; 1634 } 1635 1636 /* 1637 * Try again with this object's new backing object. 1638 */ 1639 } 1640 } 1641 1642 /* 1643 * vm_object_page_remove: [internal] 1644 * 1645 * Removes all physical pages in the specified 1646 * object range from the object's list of pages. 1647 * 1648 * The object must be locked. 1649 */ 1650 void 1651 vm_object_page_remove(vm_object_t object, vm_pindex_t start, vm_pindex_t end, boolean_t clean_only) 1652 { 1653 vm_page_t p, next; 1654 int all; 1655 1656 if (object == NULL || 1657 object->resident_page_count == 0) 1658 return; 1659 all = ((end == 0) && (start == 0)); 1660 1661 /* 1662 * Since physically-backed objects do not use managed pages, we can't 1663 * remove pages from the object (we must instead remove the page 1664 * references, and then destroy the object). 1665 */ 1666 KASSERT(object->type != OBJT_PHYS, ("attempt to remove pages from a physical object")); 1667 1668 vm_object_pip_add(object, 1); 1669 again: 1670 vm_page_lock_queues(); 1671 if ((p = TAILQ_FIRST(&object->memq)) != NULL) { 1672 if (p->pindex < start) { 1673 p = vm_page_splay(start, object->root); 1674 if ((object->root = p)->pindex < start) 1675 p = TAILQ_NEXT(p, listq); 1676 } 1677 } 1678 /* 1679 * Assert: the variable p is either (1) the page with the 1680 * least pindex greater than or equal to the parameter pindex 1681 * or (2) NULL. 1682 */ 1683 for (; 1684 p != NULL && (all || p->pindex < end); 1685 p = next) { 1686 next = TAILQ_NEXT(p, listq); 1687 1688 if (p->wire_count != 0) { 1689 pmap_remove_all(p); 1690 if (!clean_only) 1691 p->valid = 0; 1692 continue; 1693 } 1694 if (vm_page_sleep_if_busy(p, TRUE, "vmopar")) 1695 goto again; 1696 if (clean_only && p->valid) { 1697 vm_page_test_dirty(p); 1698 if (p->valid & p->dirty) 1699 continue; 1700 } 1701 vm_page_busy(p); 1702 pmap_remove_all(p); 1703 vm_page_free(p); 1704 } 1705 vm_page_unlock_queues(); 1706 vm_object_pip_wakeup(object); 1707 } 1708 1709 /* 1710 * Routine: vm_object_coalesce 1711 * Function: Coalesces two objects backing up adjoining 1712 * regions of memory into a single object. 1713 * 1714 * returns TRUE if objects were combined. 1715 * 1716 * NOTE: Only works at the moment if the second object is NULL - 1717 * if it's not, which object do we lock first? 1718 * 1719 * Parameters: 1720 * prev_object First object to coalesce 1721 * prev_offset Offset into prev_object 1722 * next_object Second object into coalesce 1723 * next_offset Offset into next_object 1724 * 1725 * prev_size Size of reference to prev_object 1726 * next_size Size of reference to next_object 1727 * 1728 * Conditions: 1729 * The object must *not* be locked. 1730 */ 1731 boolean_t 1732 vm_object_coalesce(vm_object_t prev_object, vm_pindex_t prev_pindex, 1733 vm_size_t prev_size, vm_size_t next_size) 1734 { 1735 vm_pindex_t next_pindex; 1736 1737 if (prev_object == NULL) 1738 return (TRUE); 1739 vm_object_lock(prev_object); 1740 if (prev_object->type != OBJT_DEFAULT && 1741 prev_object->type != OBJT_SWAP) { 1742 vm_object_unlock(prev_object); 1743 return (FALSE); 1744 } 1745 1746 /* 1747 * Try to collapse the object first 1748 */ 1749 vm_object_collapse(prev_object); 1750 1751 /* 1752 * Can't coalesce if: . more than one reference . paged out . shadows 1753 * another object . has a copy elsewhere (any of which mean that the 1754 * pages not mapped to prev_entry may be in use anyway) 1755 */ 1756 if (prev_object->backing_object != NULL) { 1757 vm_object_unlock(prev_object); 1758 return (FALSE); 1759 } 1760 1761 prev_size >>= PAGE_SHIFT; 1762 next_size >>= PAGE_SHIFT; 1763 next_pindex = prev_pindex + prev_size; 1764 1765 if ((prev_object->ref_count > 1) && 1766 (prev_object->size != next_pindex)) { 1767 vm_object_unlock(prev_object); 1768 return (FALSE); 1769 } 1770 1771 /* 1772 * Remove any pages that may still be in the object from a previous 1773 * deallocation. 1774 */ 1775 if (next_pindex < prev_object->size) { 1776 vm_object_page_remove(prev_object, 1777 next_pindex, 1778 next_pindex + next_size, FALSE); 1779 if (prev_object->type == OBJT_SWAP) 1780 swap_pager_freespace(prev_object, 1781 next_pindex, next_size); 1782 } 1783 1784 /* 1785 * Extend the object if necessary. 1786 */ 1787 if (next_pindex + next_size > prev_object->size) 1788 prev_object->size = next_pindex + next_size; 1789 1790 vm_object_unlock(prev_object); 1791 return (TRUE); 1792 } 1793 1794 void 1795 vm_object_set_writeable_dirty(vm_object_t object) 1796 { 1797 struct vnode *vp; 1798 1799 vm_object_set_flag(object, OBJ_WRITEABLE|OBJ_MIGHTBEDIRTY); 1800 if (object->type == OBJT_VNODE && 1801 (vp = (struct vnode *)object->handle) != NULL) { 1802 VI_LOCK(vp); 1803 if ((vp->v_iflag & VI_OBJDIRTY) == 0) 1804 vp->v_iflag |= VI_OBJDIRTY; 1805 VI_UNLOCK(vp); 1806 } 1807 } 1808 1809 #include "opt_ddb.h" 1810 #ifdef DDB 1811 #include <sys/kernel.h> 1812 1813 #include <sys/cons.h> 1814 1815 #include <ddb/ddb.h> 1816 1817 static int 1818 _vm_object_in_map(vm_map_t map, vm_object_t object, vm_map_entry_t entry) 1819 { 1820 vm_map_t tmpm; 1821 vm_map_entry_t tmpe; 1822 vm_object_t obj; 1823 int entcount; 1824 1825 if (map == 0) 1826 return 0; 1827 1828 if (entry == 0) { 1829 tmpe = map->header.next; 1830 entcount = map->nentries; 1831 while (entcount-- && (tmpe != &map->header)) { 1832 if (_vm_object_in_map(map, object, tmpe)) { 1833 return 1; 1834 } 1835 tmpe = tmpe->next; 1836 } 1837 } else if (entry->eflags & MAP_ENTRY_IS_SUB_MAP) { 1838 tmpm = entry->object.sub_map; 1839 tmpe = tmpm->header.next; 1840 entcount = tmpm->nentries; 1841 while (entcount-- && tmpe != &tmpm->header) { 1842 if (_vm_object_in_map(tmpm, object, tmpe)) { 1843 return 1; 1844 } 1845 tmpe = tmpe->next; 1846 } 1847 } else if ((obj = entry->object.vm_object) != NULL) { 1848 for (; obj; obj = obj->backing_object) 1849 if (obj == object) { 1850 return 1; 1851 } 1852 } 1853 return 0; 1854 } 1855 1856 static int 1857 vm_object_in_map(vm_object_t object) 1858 { 1859 struct proc *p; 1860 1861 /* sx_slock(&allproc_lock); */ 1862 LIST_FOREACH(p, &allproc, p_list) { 1863 if (!p->p_vmspace /* || (p->p_flag & (P_SYSTEM|P_WEXIT)) */) 1864 continue; 1865 if (_vm_object_in_map(&p->p_vmspace->vm_map, object, 0)) { 1866 /* sx_sunlock(&allproc_lock); */ 1867 return 1; 1868 } 1869 } 1870 /* sx_sunlock(&allproc_lock); */ 1871 if (_vm_object_in_map(kernel_map, object, 0)) 1872 return 1; 1873 if (_vm_object_in_map(kmem_map, object, 0)) 1874 return 1; 1875 if (_vm_object_in_map(pager_map, object, 0)) 1876 return 1; 1877 if (_vm_object_in_map(buffer_map, object, 0)) 1878 return 1; 1879 return 0; 1880 } 1881 1882 DB_SHOW_COMMAND(vmochk, vm_object_check) 1883 { 1884 vm_object_t object; 1885 1886 /* 1887 * make sure that internal objs are in a map somewhere 1888 * and none have zero ref counts. 1889 */ 1890 TAILQ_FOREACH(object, &vm_object_list, object_list) { 1891 if (object->handle == NULL && 1892 (object->type == OBJT_DEFAULT || object->type == OBJT_SWAP)) { 1893 if (object->ref_count == 0) { 1894 db_printf("vmochk: internal obj has zero ref count: %ld\n", 1895 (long)object->size); 1896 } 1897 if (!vm_object_in_map(object)) { 1898 db_printf( 1899 "vmochk: internal obj is not in a map: " 1900 "ref: %d, size: %lu: 0x%lx, backing_object: %p\n", 1901 object->ref_count, (u_long)object->size, 1902 (u_long)object->size, 1903 (void *)object->backing_object); 1904 } 1905 } 1906 } 1907 } 1908 1909 /* 1910 * vm_object_print: [ debug ] 1911 */ 1912 DB_SHOW_COMMAND(object, vm_object_print_static) 1913 { 1914 /* XXX convert args. */ 1915 vm_object_t object = (vm_object_t)addr; 1916 boolean_t full = have_addr; 1917 1918 vm_page_t p; 1919 1920 /* XXX count is an (unused) arg. Avoid shadowing it. */ 1921 #define count was_count 1922 1923 int count; 1924 1925 if (object == NULL) 1926 return; 1927 1928 db_iprintf( 1929 "Object %p: type=%d, size=0x%jx, res=%d, ref=%d, flags=0x%x\n", 1930 object, (int)object->type, (uintmax_t)object->size, 1931 object->resident_page_count, object->ref_count, object->flags); 1932 db_iprintf(" sref=%d, backing_object(%d)=(%p)+0x%jx\n", 1933 object->shadow_count, 1934 object->backing_object ? object->backing_object->ref_count : 0, 1935 object->backing_object, (uintmax_t)object->backing_object_offset); 1936 1937 if (!full) 1938 return; 1939 1940 db_indent += 2; 1941 count = 0; 1942 TAILQ_FOREACH(p, &object->memq, listq) { 1943 if (count == 0) 1944 db_iprintf("memory:="); 1945 else if (count == 6) { 1946 db_printf("\n"); 1947 db_iprintf(" ..."); 1948 count = 0; 1949 } else 1950 db_printf(","); 1951 count++; 1952 1953 db_printf("(off=0x%jx,page=0x%jx)", 1954 (uintmax_t)p->pindex, (uintmax_t)VM_PAGE_TO_PHYS(p)); 1955 } 1956 if (count != 0) 1957 db_printf("\n"); 1958 db_indent -= 2; 1959 } 1960 1961 /* XXX. */ 1962 #undef count 1963 1964 /* XXX need this non-static entry for calling from vm_map_print. */ 1965 void 1966 vm_object_print( 1967 /* db_expr_t */ long addr, 1968 boolean_t have_addr, 1969 /* db_expr_t */ long count, 1970 char *modif) 1971 { 1972 vm_object_print_static(addr, have_addr, count, modif); 1973 } 1974 1975 DB_SHOW_COMMAND(vmopag, vm_object_print_pages) 1976 { 1977 vm_object_t object; 1978 int nl = 0; 1979 int c; 1980 1981 TAILQ_FOREACH(object, &vm_object_list, object_list) { 1982 vm_pindex_t idx, fidx; 1983 vm_pindex_t osize; 1984 vm_offset_t pa = -1, padiff; 1985 int rcount; 1986 vm_page_t m; 1987 1988 db_printf("new object: %p\n", (void *)object); 1989 if (nl > 18) { 1990 c = cngetc(); 1991 if (c != ' ') 1992 return; 1993 nl = 0; 1994 } 1995 nl++; 1996 rcount = 0; 1997 fidx = 0; 1998 osize = object->size; 1999 if (osize > 128) 2000 osize = 128; 2001 for (idx = 0; idx < osize; idx++) { 2002 m = vm_page_lookup(object, idx); 2003 if (m == NULL) { 2004 if (rcount) { 2005 db_printf(" index(%ld)run(%d)pa(0x%lx)\n", 2006 (long)fidx, rcount, (long)pa); 2007 if (nl > 18) { 2008 c = cngetc(); 2009 if (c != ' ') 2010 return; 2011 nl = 0; 2012 } 2013 nl++; 2014 rcount = 0; 2015 } 2016 continue; 2017 } 2018 2019 2020 if (rcount && 2021 (VM_PAGE_TO_PHYS(m) == pa + rcount * PAGE_SIZE)) { 2022 ++rcount; 2023 continue; 2024 } 2025 if (rcount) { 2026 padiff = pa + rcount * PAGE_SIZE - VM_PAGE_TO_PHYS(m); 2027 padiff >>= PAGE_SHIFT; 2028 padiff &= PQ_L2_MASK; 2029 if (padiff == 0) { 2030 pa = VM_PAGE_TO_PHYS(m) - rcount * PAGE_SIZE; 2031 ++rcount; 2032 continue; 2033 } 2034 db_printf(" index(%ld)run(%d)pa(0x%lx)", 2035 (long)fidx, rcount, (long)pa); 2036 db_printf("pd(%ld)\n", (long)padiff); 2037 if (nl > 18) { 2038 c = cngetc(); 2039 if (c != ' ') 2040 return; 2041 nl = 0; 2042 } 2043 nl++; 2044 } 2045 fidx = idx; 2046 pa = VM_PAGE_TO_PHYS(m); 2047 rcount = 1; 2048 } 2049 if (rcount) { 2050 db_printf(" index(%ld)run(%d)pa(0x%lx)\n", 2051 (long)fidx, rcount, (long)pa); 2052 if (nl > 18) { 2053 c = cngetc(); 2054 if (c != ' ') 2055 return; 2056 nl = 0; 2057 } 2058 nl++; 2059 } 2060 } 2061 } 2062 #endif /* DDB */ 2063