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 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 uma_zone_t obj_zone; 151 #define VM_OBJECTS_INIT 256 152 153 static void vm_object_zinit(void *mem, int size); 154 155 #ifdef INVARIANTS 156 static void vm_object_zdtor(void *mem, int size, void *arg); 157 158 static void 159 vm_object_zdtor(void *mem, int size, void *arg) 160 { 161 vm_object_t object; 162 163 object = (vm_object_t)mem; 164 KASSERT(object->paging_in_progress == 0, 165 ("object %p paging_in_progress = %d", 166 object, object->paging_in_progress)); 167 KASSERT(object->resident_page_count == 0, 168 ("object %p resident_page_count = %d", 169 object, object->resident_page_count)); 170 KASSERT(object->shadow_count == 0, 171 ("object %p shadow_count = %d", 172 object, object->shadow_count)); 173 } 174 #endif 175 176 static void 177 vm_object_zinit(void *mem, int size) 178 { 179 vm_object_t object; 180 181 object = (vm_object_t)mem; 182 bzero(&object->mtx, sizeof(object->mtx)); 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_pindex_t size, vm_object_t object) 192 { 193 int incr; 194 195 mtx_init(&object->mtx, "vm object", NULL, MTX_DEF); 196 197 TAILQ_INIT(&object->memq); 198 TAILQ_INIT(&object->shadow_head); 199 200 object->root = NULL; 201 object->type = type; 202 object->size = size; 203 object->ref_count = 1; 204 object->flags = 0; 205 if ((object->type == OBJT_DEFAULT) || (object->type == OBJT_SWAP)) 206 vm_object_set_flag(object, OBJ_ONEMAPPING); 207 if (size > (PQ_L2_SIZE / 3 + PQ_PRIME1)) 208 incr = PQ_L2_SIZE / 3 + PQ_PRIME1; 209 else 210 incr = size; 211 do 212 object->pg_color = next_index; 213 while (!atomic_cmpset_int(&next_index, object->pg_color, 214 (object->pg_color + incr) & PQ_L2_MASK)); 215 object->handle = NULL; 216 object->backing_object = NULL; 217 object->backing_object_offset = (vm_ooffset_t) 0; 218 219 atomic_add_int(&object->generation, 1); 220 221 mtx_lock(&vm_object_list_mtx); 222 TAILQ_INSERT_TAIL(&vm_object_list, object, object_list); 223 mtx_unlock(&vm_object_list_mtx); 224 } 225 226 /* 227 * vm_object_init: 228 * 229 * Initialize the VM objects module. 230 */ 231 void 232 vm_object_init(void) 233 { 234 TAILQ_INIT(&vm_object_list); 235 mtx_init(&vm_object_list_mtx, "vm object_list", NULL, MTX_DEF); 236 237 kernel_object = &kernel_object_store; 238 _vm_object_allocate(OBJT_DEFAULT, OFF_TO_IDX(VM_MAX_KERNEL_ADDRESS - VM_MIN_KERNEL_ADDRESS), 239 kernel_object); 240 241 kmem_object = &kmem_object_store; 242 _vm_object_allocate(OBJT_DEFAULT, OFF_TO_IDX(VM_MAX_KERNEL_ADDRESS - VM_MIN_KERNEL_ADDRESS), 243 kmem_object); 244 obj_zone = uma_zcreate("VM OBJECT", sizeof (struct vm_object), NULL, 245 #ifdef INVARIANTS 246 vm_object_zdtor, 247 #else 248 NULL, 249 #endif 250 vm_object_zinit, NULL, UMA_ALIGN_PTR, UMA_ZONE_NOFREE); 251 uma_prealloc(obj_zone, VM_OBJECTS_INIT); 252 } 253 254 void 255 vm_object_set_flag(vm_object_t object, u_short bits) 256 { 257 object->flags |= bits; 258 } 259 260 void 261 vm_object_clear_flag(vm_object_t object, u_short bits) 262 { 263 264 mtx_assert(object == kmem_object ? &object->mtx : &Giant, MA_OWNED); 265 object->flags &= ~bits; 266 } 267 268 void 269 vm_object_pip_add(vm_object_t object, short i) 270 { 271 GIANT_REQUIRED; 272 object->paging_in_progress += i; 273 } 274 275 void 276 vm_object_pip_subtract(vm_object_t object, short i) 277 { 278 GIANT_REQUIRED; 279 object->paging_in_progress -= i; 280 } 281 282 void 283 vm_object_pip_wakeup(vm_object_t object) 284 { 285 GIANT_REQUIRED; 286 object->paging_in_progress--; 287 if ((object->flags & OBJ_PIPWNT) && object->paging_in_progress == 0) { 288 vm_object_clear_flag(object, OBJ_PIPWNT); 289 wakeup(object); 290 } 291 } 292 293 void 294 vm_object_pip_wakeupn(vm_object_t object, short i) 295 { 296 GIANT_REQUIRED; 297 if (i) 298 object->paging_in_progress -= i; 299 if ((object->flags & OBJ_PIPWNT) && object->paging_in_progress == 0) { 300 vm_object_clear_flag(object, OBJ_PIPWNT); 301 wakeup(object); 302 } 303 } 304 305 void 306 vm_object_pip_sleep(vm_object_t object, char *waitid) 307 { 308 GIANT_REQUIRED; 309 if (object->paging_in_progress) { 310 int s = splvm(); 311 if (object->paging_in_progress) { 312 vm_object_set_flag(object, OBJ_PIPWNT); 313 tsleep(object, PVM, waitid, 0); 314 } 315 splx(s); 316 } 317 } 318 319 void 320 vm_object_pip_wait(vm_object_t object, char *waitid) 321 { 322 GIANT_REQUIRED; 323 while (object->paging_in_progress) 324 vm_object_pip_sleep(object, waitid); 325 } 326 327 /* 328 * vm_object_allocate_wait 329 * 330 * Return a new object with the given size, and give the user the 331 * option of waiting for it to complete or failing if the needed 332 * memory isn't available. 333 */ 334 vm_object_t 335 vm_object_allocate_wait(objtype_t type, vm_pindex_t size, int flags) 336 { 337 vm_object_t result; 338 339 result = (vm_object_t) uma_zalloc(obj_zone, flags); 340 341 if (result != NULL) 342 _vm_object_allocate(type, size, result); 343 344 return (result); 345 } 346 347 /* 348 * vm_object_allocate: 349 * 350 * Returns a new object with the given size. 351 */ 352 vm_object_t 353 vm_object_allocate(objtype_t type, vm_pindex_t size) 354 { 355 return(vm_object_allocate_wait(type, size, M_WAITOK)); 356 } 357 358 359 /* 360 * vm_object_reference: 361 * 362 * Gets another reference to the given object. 363 */ 364 void 365 vm_object_reference(vm_object_t object) 366 { 367 if (object == NULL) 368 return; 369 370 vm_object_lock(object); 371 #if 0 372 /* object can be re-referenced during final cleaning */ 373 KASSERT(!(object->flags & OBJ_DEAD), 374 ("vm_object_reference: attempting to reference dead obj")); 375 #endif 376 377 object->ref_count++; 378 if (object->type == OBJT_VNODE) { 379 while (vget((struct vnode *) object->handle, LK_RETRY, curthread)) { 380 printf("vm_object_reference: delay in getting object\n"); 381 } 382 } 383 vm_object_unlock(object); 384 } 385 386 /* 387 * Handle deallocating an object of type OBJT_VNODE. 388 */ 389 void 390 vm_object_vndeallocate(vm_object_t object) 391 { 392 struct vnode *vp = (struct vnode *) object->handle; 393 394 GIANT_REQUIRED; 395 KASSERT(object->type == OBJT_VNODE, 396 ("vm_object_vndeallocate: not a vnode object")); 397 KASSERT(vp != NULL, ("vm_object_vndeallocate: missing vp")); 398 #ifdef INVARIANTS 399 if (object->ref_count == 0) { 400 vprint("vm_object_vndeallocate", vp); 401 panic("vm_object_vndeallocate: bad object reference count"); 402 } 403 #endif 404 405 object->ref_count--; 406 if (object->ref_count == 0) { 407 mp_fixme("Unlocked vflag access."); 408 vp->v_vflag &= ~VV_TEXT; 409 } 410 /* 411 * vrele may need a vop lock 412 */ 413 vrele(vp); 414 } 415 416 /* 417 * vm_object_deallocate: 418 * 419 * Release a reference to the specified object, 420 * gained either through a vm_object_allocate 421 * or a vm_object_reference call. When all references 422 * are gone, storage associated with this object 423 * may be relinquished. 424 * 425 * No object may be locked. 426 */ 427 void 428 vm_object_deallocate(vm_object_t object) 429 { 430 vm_object_t temp; 431 432 vm_object_lock(object); 433 while (object != NULL) { 434 435 if (object->type == OBJT_VNODE) { 436 vm_object_vndeallocate(object); 437 vm_object_unlock(object); 438 return; 439 } 440 441 KASSERT(object->ref_count != 0, 442 ("vm_object_deallocate: object deallocated too many times: %d", object->type)); 443 444 /* 445 * If the reference count goes to 0 we start calling 446 * vm_object_terminate() on the object chain. 447 * A ref count of 1 may be a special case depending on the 448 * shadow count being 0 or 1. 449 */ 450 object->ref_count--; 451 if (object->ref_count > 1) { 452 vm_object_unlock(object); 453 return; 454 } else if (object->ref_count == 1) { 455 if (object->shadow_count == 0) { 456 vm_object_set_flag(object, OBJ_ONEMAPPING); 457 } else if ((object->shadow_count == 1) && 458 (object->handle == NULL) && 459 (object->type == OBJT_DEFAULT || 460 object->type == OBJT_SWAP)) { 461 vm_object_t robject; 462 463 robject = TAILQ_FIRST(&object->shadow_head); 464 KASSERT(robject != NULL, 465 ("vm_object_deallocate: ref_count: %d, shadow_count: %d", 466 object->ref_count, 467 object->shadow_count)); 468 if ((robject->handle == NULL) && 469 (robject->type == OBJT_DEFAULT || 470 robject->type == OBJT_SWAP)) { 471 472 robject->ref_count++; 473 474 while ( 475 robject->paging_in_progress || 476 object->paging_in_progress 477 ) { 478 vm_object_pip_sleep(robject, "objde1"); 479 vm_object_pip_sleep(object, "objde2"); 480 } 481 482 if (robject->ref_count == 1) { 483 robject->ref_count--; 484 object = robject; 485 goto doterm; 486 } 487 488 object = robject; 489 vm_object_collapse(object); 490 continue; 491 } 492 } 493 vm_object_unlock(object); 494 return; 495 } 496 doterm: 497 temp = object->backing_object; 498 if (temp) { 499 TAILQ_REMOVE(&temp->shadow_head, object, shadow_list); 500 temp->shadow_count--; 501 temp->generation++; 502 object->backing_object = NULL; 503 } 504 /* 505 * Don't double-terminate, we could be in a termination 506 * recursion due to the terminate having to sync data 507 * to disk. 508 */ 509 if ((object->flags & OBJ_DEAD) == 0) 510 vm_object_terminate(object); 511 object = temp; 512 } 513 vm_object_unlock(object); 514 } 515 516 /* 517 * vm_object_terminate actually destroys the specified object, freeing 518 * up all previously used resources. 519 * 520 * The object must be locked. 521 * This routine may block. 522 */ 523 void 524 vm_object_terminate(vm_object_t object) 525 { 526 vm_page_t p; 527 int s; 528 529 GIANT_REQUIRED; 530 531 /* 532 * Make sure no one uses us. 533 */ 534 vm_object_set_flag(object, OBJ_DEAD); 535 536 /* 537 * wait for the pageout daemon to be done with the object 538 */ 539 vm_object_pip_wait(object, "objtrm"); 540 541 KASSERT(!object->paging_in_progress, 542 ("vm_object_terminate: pageout in progress")); 543 544 /* 545 * Clean and free the pages, as appropriate. All references to the 546 * object are gone, so we don't need to lock it. 547 */ 548 if (object->type == OBJT_VNODE) { 549 struct vnode *vp; 550 551 /* 552 * Clean pages and flush buffers. 553 */ 554 vm_object_page_clean(object, 0, 0, OBJPC_SYNC); 555 556 vp = (struct vnode *) object->handle; 557 vinvalbuf(vp, V_SAVE, NOCRED, NULL, 0, 0); 558 } 559 560 KASSERT(object->ref_count == 0, 561 ("vm_object_terminate: object with references, ref_count=%d", 562 object->ref_count)); 563 564 /* 565 * Now free any remaining pages. For internal objects, this also 566 * removes them from paging queues. Don't free wired pages, just 567 * remove them from the object. 568 */ 569 s = splvm(); 570 vm_page_lock_queues(); 571 while ((p = TAILQ_FIRST(&object->memq)) != NULL) { 572 KASSERT(!p->busy && (p->flags & PG_BUSY) == 0, 573 ("vm_object_terminate: freeing busy page %p " 574 "p->busy = %d, p->flags %x\n", p, p->busy, p->flags)); 575 if (p->wire_count == 0) { 576 vm_page_busy(p); 577 vm_page_free(p); 578 cnt.v_pfree++; 579 } else { 580 vm_page_busy(p); 581 vm_page_remove(p); 582 } 583 } 584 vm_page_unlock_queues(); 585 splx(s); 586 587 /* 588 * Let the pager know object is dead. 589 */ 590 vm_pager_deallocate(object); 591 592 /* 593 * Remove the object from the global object list. 594 */ 595 mtx_lock(&vm_object_list_mtx); 596 TAILQ_REMOVE(&vm_object_list, object, object_list); 597 mtx_unlock(&vm_object_list_mtx); 598 599 mtx_destroy(&object->mtx); 600 wakeup(object); 601 602 /* 603 * Free the space for the object. 604 */ 605 uma_zfree(obj_zone, object); 606 } 607 608 /* 609 * vm_object_page_clean 610 * 611 * Clean all dirty pages in the specified range of object. Leaves page 612 * on whatever queue it is currently on. If NOSYNC is set then do not 613 * write out pages with PG_NOSYNC set (originally comes from MAP_NOSYNC), 614 * leaving the object dirty. 615 * 616 * When stuffing pages asynchronously, allow clustering. XXX we need a 617 * synchronous clustering mode implementation. 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_pindex_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 : VM_PAGER_CLUSTER_OK; 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 vm_page_lock_queues(); 655 /* 656 * If the caller is smart and only msync()s a range he knows is 657 * dirty, we may be able to avoid an object scan. This results in 658 * a phenominal improvement in performance. We cannot do this 659 * as a matter of course because the object may be huge - e.g. 660 * the size might be in the gigabytes or terrabytes. 661 */ 662 if (msync_flush_flags & MSYNC_FLUSH_HARDSEQ) { 663 vm_pindex_t tscan; 664 int scanlimit; 665 int scanreset; 666 667 scanreset = object->resident_page_count / EASY_SCAN_FACTOR; 668 if (scanreset < 16) 669 scanreset = 16; 670 pagerflags |= VM_PAGER_IGNORE_CLEANCHK; 671 672 scanlimit = scanreset; 673 tscan = tstart; 674 while (tscan < tend) { 675 curgeneration = object->generation; 676 p = vm_page_lookup(object, tscan); 677 if (p == NULL || p->valid == 0 || 678 (p->queue - p->pc) == PQ_CACHE) { 679 if (--scanlimit == 0) 680 break; 681 ++tscan; 682 continue; 683 } 684 vm_page_test_dirty(p); 685 if ((p->dirty & p->valid) == 0) { 686 if (--scanlimit == 0) 687 break; 688 ++tscan; 689 continue; 690 } 691 /* 692 * If we have been asked to skip nosync pages and 693 * this is a nosync page, we can't continue. 694 */ 695 if ((flags & OBJPC_NOSYNC) && (p->flags & PG_NOSYNC)) { 696 if (--scanlimit == 0) 697 break; 698 ++tscan; 699 continue; 700 } 701 scanlimit = scanreset; 702 703 /* 704 * This returns 0 if it was unable to busy the first 705 * page (i.e. had to sleep). 706 */ 707 tscan += vm_object_page_collect_flush(object, p, curgeneration, pagerflags); 708 } 709 710 /* 711 * If everything was dirty and we flushed it successfully, 712 * and the requested range is not the entire object, we 713 * don't have to mess with CLEANCHK or MIGHTBEDIRTY and can 714 * return immediately. 715 */ 716 if (tscan >= tend && (tstart || tend < object->size)) { 717 vm_page_unlock_queues(); 718 vm_object_clear_flag(object, OBJ_CLEANING); 719 return; 720 } 721 pagerflags &= ~VM_PAGER_IGNORE_CLEANCHK; 722 } 723 724 /* 725 * Generally set CLEANCHK interlock and make the page read-only so 726 * we can then clear the object flags. 727 * 728 * However, if this is a nosync mmap then the object is likely to 729 * stay dirty so do not mess with the page and do not clear the 730 * object flags. 731 */ 732 clearobjflags = 1; 733 TAILQ_FOREACH(p, &object->memq, listq) { 734 vm_page_flag_set(p, PG_CLEANCHK); 735 if ((flags & OBJPC_NOSYNC) && (p->flags & PG_NOSYNC)) 736 clearobjflags = 0; 737 else 738 pmap_page_protect(p, VM_PROT_READ); 739 } 740 741 if (clearobjflags && (tstart == 0) && (tend == object->size)) { 742 struct vnode *vp; 743 744 vm_object_clear_flag(object, OBJ_WRITEABLE|OBJ_MIGHTBEDIRTY); 745 if (object->type == OBJT_VNODE && 746 (vp = (struct vnode *)object->handle) != NULL) { 747 VI_LOCK(vp); 748 if (vp->v_iflag & VI_OBJDIRTY) 749 vp->v_iflag &= ~VI_OBJDIRTY; 750 VI_UNLOCK(vp); 751 } 752 } 753 754 rescan: 755 curgeneration = object->generation; 756 757 for (p = TAILQ_FIRST(&object->memq); p; p = np) { 758 int n; 759 760 np = TAILQ_NEXT(p, listq); 761 762 again: 763 pi = p->pindex; 764 if (((p->flags & PG_CLEANCHK) == 0) || 765 (pi < tstart) || (pi >= tend) || 766 (p->valid == 0) || 767 ((p->queue - p->pc) == PQ_CACHE)) { 768 vm_page_flag_clear(p, PG_CLEANCHK); 769 continue; 770 } 771 772 vm_page_test_dirty(p); 773 if ((p->dirty & p->valid) == 0) { 774 vm_page_flag_clear(p, PG_CLEANCHK); 775 continue; 776 } 777 778 /* 779 * If we have been asked to skip nosync pages and this is a 780 * nosync page, skip it. Note that the object flags were 781 * not cleared in this case so we do not have to set them. 782 */ 783 if ((flags & OBJPC_NOSYNC) && (p->flags & PG_NOSYNC)) { 784 vm_page_flag_clear(p, PG_CLEANCHK); 785 continue; 786 } 787 788 n = vm_object_page_collect_flush(object, p, 789 curgeneration, pagerflags); 790 if (n == 0) 791 goto rescan; 792 793 if (object->generation != curgeneration) 794 goto rescan; 795 796 /* 797 * Try to optimize the next page. If we can't we pick up 798 * our (random) scan where we left off. 799 */ 800 if (msync_flush_flags & MSYNC_FLUSH_SOFTSEQ) { 801 if ((p = vm_page_lookup(object, pi + n)) != NULL) 802 goto again; 803 } 804 } 805 vm_page_unlock_queues(); 806 #if 0 807 VOP_FSYNC(vp, NULL, (pagerflags & VM_PAGER_PUT_SYNC)?MNT_WAIT:0, curproc); 808 #endif 809 810 vm_object_clear_flag(object, OBJ_CLEANING); 811 return; 812 } 813 814 static int 815 vm_object_page_collect_flush(vm_object_t object, vm_page_t p, int curgeneration, int pagerflags) 816 { 817 int runlen; 818 int s; 819 int maxf; 820 int chkb; 821 int maxb; 822 int i; 823 vm_pindex_t pi; 824 vm_page_t maf[vm_pageout_page_count]; 825 vm_page_t mab[vm_pageout_page_count]; 826 vm_page_t ma[vm_pageout_page_count]; 827 828 s = splvm(); 829 mtx_assert(&vm_page_queue_mtx, MA_OWNED); 830 pi = p->pindex; 831 while (vm_page_sleep_if_busy(p, TRUE, "vpcwai")) { 832 vm_page_lock_queues(); 833 if (object->generation != curgeneration) { 834 splx(s); 835 return(0); 836 } 837 } 838 maxf = 0; 839 for(i = 1; i < vm_pageout_page_count; i++) { 840 vm_page_t tp; 841 842 if ((tp = vm_page_lookup(object, pi + i)) != NULL) { 843 if ((tp->flags & PG_BUSY) || 844 ((pagerflags & VM_PAGER_IGNORE_CLEANCHK) == 0 && 845 (tp->flags & PG_CLEANCHK) == 0) || 846 (tp->busy != 0)) 847 break; 848 if((tp->queue - tp->pc) == PQ_CACHE) { 849 vm_page_flag_clear(tp, PG_CLEANCHK); 850 break; 851 } 852 vm_page_test_dirty(tp); 853 if ((tp->dirty & tp->valid) == 0) { 854 vm_page_flag_clear(tp, PG_CLEANCHK); 855 break; 856 } 857 maf[ i - 1 ] = tp; 858 maxf++; 859 continue; 860 } 861 break; 862 } 863 864 maxb = 0; 865 chkb = vm_pageout_page_count - maxf; 866 if (chkb) { 867 for(i = 1; i < chkb;i++) { 868 vm_page_t tp; 869 870 if ((tp = vm_page_lookup(object, pi - i)) != NULL) { 871 if ((tp->flags & PG_BUSY) || 872 ((pagerflags & VM_PAGER_IGNORE_CLEANCHK) == 0 && 873 (tp->flags & PG_CLEANCHK) == 0) || 874 (tp->busy != 0)) 875 break; 876 if ((tp->queue - tp->pc) == PQ_CACHE) { 877 vm_page_flag_clear(tp, PG_CLEANCHK); 878 break; 879 } 880 vm_page_test_dirty(tp); 881 if ((tp->dirty & tp->valid) == 0) { 882 vm_page_flag_clear(tp, PG_CLEANCHK); 883 break; 884 } 885 mab[ i - 1 ] = tp; 886 maxb++; 887 continue; 888 } 889 break; 890 } 891 } 892 893 for(i = 0; i < maxb; i++) { 894 int index = (maxb - i) - 1; 895 ma[index] = mab[i]; 896 vm_page_flag_clear(ma[index], PG_CLEANCHK); 897 } 898 vm_page_flag_clear(p, PG_CLEANCHK); 899 ma[maxb] = p; 900 for(i = 0; i < maxf; i++) { 901 int index = (maxb + i) + 1; 902 ma[index] = maf[i]; 903 vm_page_flag_clear(ma[index], PG_CLEANCHK); 904 } 905 runlen = maxb + maxf + 1; 906 907 splx(s); 908 vm_pageout_flush(ma, runlen, pagerflags); 909 for (i = 0; i < runlen; i++) { 910 if (ma[i]->valid & ma[i]->dirty) { 911 pmap_page_protect(ma[i], VM_PROT_READ); 912 vm_page_flag_set(ma[i], PG_CLEANCHK); 913 914 /* 915 * maxf will end up being the actual number of pages 916 * we wrote out contiguously, non-inclusive of the 917 * first page. We do not count look-behind pages. 918 */ 919 if (i >= maxb + 1 && (maxf > i - maxb - 1)) 920 maxf = i - maxb - 1; 921 } 922 } 923 return(maxf + 1); 924 } 925 926 /* 927 * vm_object_madvise: 928 * 929 * Implements the madvise function at the object/page level. 930 * 931 * MADV_WILLNEED (any object) 932 * 933 * Activate the specified pages if they are resident. 934 * 935 * MADV_DONTNEED (any object) 936 * 937 * Deactivate the specified pages if they are resident. 938 * 939 * MADV_FREE (OBJT_DEFAULT/OBJT_SWAP objects, 940 * OBJ_ONEMAPPING only) 941 * 942 * Deactivate and clean the specified pages if they are 943 * resident. This permits the process to reuse the pages 944 * without faulting or the kernel to reclaim the pages 945 * without I/O. 946 */ 947 void 948 vm_object_madvise(vm_object_t object, vm_pindex_t pindex, int count, int advise) 949 { 950 vm_pindex_t end, tpindex; 951 vm_object_t tobject; 952 vm_page_t m; 953 954 if (object == NULL) 955 return; 956 957 vm_object_lock(object); 958 959 end = pindex + count; 960 961 /* 962 * Locate and adjust resident pages 963 */ 964 for (; pindex < end; pindex += 1) { 965 relookup: 966 tobject = object; 967 tpindex = pindex; 968 shadowlookup: 969 /* 970 * MADV_FREE only operates on OBJT_DEFAULT or OBJT_SWAP pages 971 * and those pages must be OBJ_ONEMAPPING. 972 */ 973 if (advise == MADV_FREE) { 974 if ((tobject->type != OBJT_DEFAULT && 975 tobject->type != OBJT_SWAP) || 976 (tobject->flags & OBJ_ONEMAPPING) == 0) { 977 continue; 978 } 979 } 980 981 m = vm_page_lookup(tobject, tpindex); 982 983 if (m == NULL) { 984 /* 985 * There may be swap even if there is no backing page 986 */ 987 if (advise == MADV_FREE && tobject->type == OBJT_SWAP) 988 swap_pager_freespace(tobject, tpindex, 1); 989 990 /* 991 * next object 992 */ 993 tobject = tobject->backing_object; 994 if (tobject == NULL) 995 continue; 996 tpindex += OFF_TO_IDX(tobject->backing_object_offset); 997 goto shadowlookup; 998 } 999 1000 /* 1001 * If the page is busy or not in a normal active state, 1002 * we skip it. If the page is not managed there are no 1003 * page queues to mess with. Things can break if we mess 1004 * with pages in any of the below states. 1005 */ 1006 vm_page_lock_queues(); 1007 if (m->hold_count || 1008 m->wire_count || 1009 (m->flags & PG_UNMANAGED) || 1010 m->valid != VM_PAGE_BITS_ALL) { 1011 vm_page_unlock_queues(); 1012 continue; 1013 } 1014 if (vm_page_sleep_if_busy(m, TRUE, "madvpo")) 1015 goto relookup; 1016 if (advise == MADV_WILLNEED) { 1017 vm_page_activate(m); 1018 } else if (advise == MADV_DONTNEED) { 1019 vm_page_dontneed(m); 1020 } else if (advise == MADV_FREE) { 1021 /* 1022 * Mark the page clean. This will allow the page 1023 * to be freed up by the system. However, such pages 1024 * are often reused quickly by malloc()/free() 1025 * so we do not do anything that would cause 1026 * a page fault if we can help it. 1027 * 1028 * Specifically, we do not try to actually free 1029 * the page now nor do we try to put it in the 1030 * cache (which would cause a page fault on reuse). 1031 * 1032 * But we do make the page is freeable as we 1033 * can without actually taking the step of unmapping 1034 * it. 1035 */ 1036 pmap_clear_modify(m); 1037 m->dirty = 0; 1038 m->act_count = 0; 1039 vm_page_dontneed(m); 1040 } 1041 vm_page_unlock_queues(); 1042 if (advise == MADV_FREE && tobject->type == OBJT_SWAP) 1043 swap_pager_freespace(tobject, tpindex, 1); 1044 } 1045 vm_object_unlock(object); 1046 } 1047 1048 /* 1049 * vm_object_shadow: 1050 * 1051 * Create a new object which is backed by the 1052 * specified existing object range. The source 1053 * object reference is deallocated. 1054 * 1055 * The new object and offset into that object 1056 * are returned in the source parameters. 1057 */ 1058 void 1059 vm_object_shadow( 1060 vm_object_t *object, /* IN/OUT */ 1061 vm_ooffset_t *offset, /* IN/OUT */ 1062 vm_size_t length) 1063 { 1064 vm_object_t source; 1065 vm_object_t result; 1066 1067 source = *object; 1068 1069 vm_object_lock(source); 1070 /* 1071 * Don't create the new object if the old object isn't shared. 1072 */ 1073 if (source != NULL && 1074 source->ref_count == 1 && 1075 source->handle == NULL && 1076 (source->type == OBJT_DEFAULT || 1077 source->type == OBJT_SWAP)) { 1078 vm_object_unlock(source); 1079 return; 1080 } 1081 1082 /* 1083 * Allocate a new object with the given length 1084 */ 1085 result = vm_object_allocate(OBJT_DEFAULT, length); 1086 KASSERT(result != NULL, ("vm_object_shadow: no object for shadowing")); 1087 1088 /* 1089 * The new object shadows the source object, adding a reference to it. 1090 * Our caller changes his reference to point to the new object, 1091 * removing a reference to the source object. Net result: no change 1092 * of reference count. 1093 * 1094 * Try to optimize the result object's page color when shadowing 1095 * in order to maintain page coloring consistency in the combined 1096 * shadowed object. 1097 */ 1098 result->backing_object = source; 1099 if (source) { 1100 TAILQ_INSERT_TAIL(&source->shadow_head, result, shadow_list); 1101 source->shadow_count++; 1102 source->generation++; 1103 if (length < source->size) 1104 length = source->size; 1105 if (length > PQ_L2_SIZE / 3 + PQ_PRIME1 || 1106 source->generation > 1) 1107 length = PQ_L2_SIZE / 3 + PQ_PRIME1; 1108 result->pg_color = (source->pg_color + 1109 length * source->generation) & PQ_L2_MASK; 1110 next_index = (result->pg_color + PQ_L2_SIZE / 3 + PQ_PRIME1) & 1111 PQ_L2_MASK; 1112 } 1113 1114 /* 1115 * Store the offset into the source object, and fix up the offset into 1116 * the new object. 1117 */ 1118 result->backing_object_offset = *offset; 1119 1120 /* 1121 * Return the new things 1122 */ 1123 *offset = 0; 1124 *object = result; 1125 1126 vm_object_unlock(source); 1127 } 1128 1129 /* 1130 * vm_object_split: 1131 * 1132 * Split the pages in a map entry into a new object. This affords 1133 * easier removal of unused pages, and keeps object inheritance from 1134 * being a negative impact on memory usage. 1135 */ 1136 void 1137 vm_object_split(vm_map_entry_t entry) 1138 { 1139 vm_page_t m; 1140 vm_object_t orig_object, new_object, source; 1141 vm_offset_t s, e; 1142 vm_pindex_t offidxstart, offidxend; 1143 vm_size_t idx, size; 1144 vm_ooffset_t offset; 1145 1146 GIANT_REQUIRED; 1147 1148 orig_object = entry->object.vm_object; 1149 if (orig_object->type != OBJT_DEFAULT && orig_object->type != OBJT_SWAP) 1150 return; 1151 if (orig_object->ref_count <= 1) 1152 return; 1153 1154 offset = entry->offset; 1155 s = entry->start; 1156 e = entry->end; 1157 1158 offidxstart = OFF_TO_IDX(offset); 1159 offidxend = offidxstart + OFF_TO_IDX(e - s); 1160 size = offidxend - offidxstart; 1161 1162 new_object = vm_pager_allocate(orig_object->type, 1163 NULL, IDX_TO_OFF(size), VM_PROT_ALL, 0LL); 1164 if (new_object == NULL) 1165 return; 1166 1167 source = orig_object->backing_object; 1168 if (source != NULL) { 1169 vm_object_reference(source); /* Referenced by new_object */ 1170 TAILQ_INSERT_TAIL(&source->shadow_head, 1171 new_object, shadow_list); 1172 vm_object_clear_flag(source, OBJ_ONEMAPPING); 1173 new_object->backing_object_offset = 1174 orig_object->backing_object_offset + offset; 1175 new_object->backing_object = source; 1176 source->shadow_count++; 1177 source->generation++; 1178 } 1179 for (idx = 0; idx < size; idx++) { 1180 retry: 1181 m = vm_page_lookup(orig_object, offidxstart + idx); 1182 if (m == NULL) 1183 continue; 1184 1185 /* 1186 * We must wait for pending I/O to complete before we can 1187 * rename the page. 1188 * 1189 * We do not have to VM_PROT_NONE the page as mappings should 1190 * not be changed by this operation. 1191 */ 1192 vm_page_lock_queues(); 1193 if (vm_page_sleep_if_busy(m, TRUE, "spltwt")) 1194 goto retry; 1195 1196 vm_page_busy(m); 1197 vm_page_rename(m, new_object, idx); 1198 /* page automatically made dirty by rename and cache handled */ 1199 vm_page_busy(m); 1200 vm_page_unlock_queues(); 1201 } 1202 if (orig_object->type == OBJT_SWAP) { 1203 vm_object_pip_add(orig_object, 1); 1204 /* 1205 * copy orig_object pages into new_object 1206 * and destroy unneeded pages in 1207 * shadow object. 1208 */ 1209 swap_pager_copy(orig_object, new_object, offidxstart, 0); 1210 vm_object_pip_wakeup(orig_object); 1211 } 1212 vm_page_lock_queues(); 1213 TAILQ_FOREACH(m, &new_object->memq, listq) 1214 vm_page_wakeup(m); 1215 vm_page_unlock_queues(); 1216 entry->object.vm_object = new_object; 1217 entry->offset = 0LL; 1218 vm_object_deallocate(orig_object); 1219 } 1220 1221 #define OBSC_TEST_ALL_SHADOWED 0x0001 1222 #define OBSC_COLLAPSE_NOWAIT 0x0002 1223 #define OBSC_COLLAPSE_WAIT 0x0004 1224 1225 static __inline int 1226 vm_object_backing_scan(vm_object_t object, int op) 1227 { 1228 int s; 1229 int r = 1; 1230 vm_page_t p; 1231 vm_object_t backing_object; 1232 vm_pindex_t backing_offset_index; 1233 1234 s = splvm(); 1235 GIANT_REQUIRED; 1236 1237 backing_object = object->backing_object; 1238 backing_offset_index = OFF_TO_IDX(object->backing_object_offset); 1239 1240 /* 1241 * Initial conditions 1242 */ 1243 if (op & OBSC_TEST_ALL_SHADOWED) { 1244 /* 1245 * We do not want to have to test for the existence of 1246 * swap pages in the backing object. XXX but with the 1247 * new swapper this would be pretty easy to do. 1248 * 1249 * XXX what about anonymous MAP_SHARED memory that hasn't 1250 * been ZFOD faulted yet? If we do not test for this, the 1251 * shadow test may succeed! XXX 1252 */ 1253 if (backing_object->type != OBJT_DEFAULT) { 1254 splx(s); 1255 return (0); 1256 } 1257 } 1258 if (op & OBSC_COLLAPSE_WAIT) { 1259 vm_object_set_flag(backing_object, OBJ_DEAD); 1260 } 1261 1262 /* 1263 * Our scan 1264 */ 1265 p = TAILQ_FIRST(&backing_object->memq); 1266 while (p) { 1267 vm_page_t next = TAILQ_NEXT(p, listq); 1268 vm_pindex_t new_pindex = p->pindex - backing_offset_index; 1269 1270 if (op & OBSC_TEST_ALL_SHADOWED) { 1271 vm_page_t pp; 1272 1273 /* 1274 * Ignore pages outside the parent object's range 1275 * and outside the parent object's mapping of the 1276 * backing object. 1277 * 1278 * note that we do not busy the backing object's 1279 * page. 1280 */ 1281 if ( 1282 p->pindex < backing_offset_index || 1283 new_pindex >= object->size 1284 ) { 1285 p = next; 1286 continue; 1287 } 1288 1289 /* 1290 * See if the parent has the page or if the parent's 1291 * object pager has the page. If the parent has the 1292 * page but the page is not valid, the parent's 1293 * object pager must have the page. 1294 * 1295 * If this fails, the parent does not completely shadow 1296 * the object and we might as well give up now. 1297 */ 1298 1299 pp = vm_page_lookup(object, new_pindex); 1300 if ( 1301 (pp == NULL || pp->valid == 0) && 1302 !vm_pager_has_page(object, new_pindex, NULL, NULL) 1303 ) { 1304 r = 0; 1305 break; 1306 } 1307 } 1308 1309 /* 1310 * Check for busy page 1311 */ 1312 if (op & (OBSC_COLLAPSE_WAIT | OBSC_COLLAPSE_NOWAIT)) { 1313 vm_page_t pp; 1314 1315 vm_page_lock_queues(); 1316 if (op & OBSC_COLLAPSE_NOWAIT) { 1317 if ((p->flags & PG_BUSY) || 1318 !p->valid || 1319 p->hold_count || 1320 p->wire_count || 1321 p->busy) { 1322 vm_page_unlock_queues(); 1323 p = next; 1324 continue; 1325 } 1326 } else if (op & OBSC_COLLAPSE_WAIT) { 1327 if (vm_page_sleep_if_busy(p, TRUE, "vmocol")) { 1328 /* 1329 * If we slept, anything could have 1330 * happened. Since the object is 1331 * marked dead, the backing offset 1332 * should not have changed so we 1333 * just restart our scan. 1334 */ 1335 p = TAILQ_FIRST(&backing_object->memq); 1336 continue; 1337 } 1338 } 1339 1340 /* 1341 * Busy the page 1342 */ 1343 vm_page_busy(p); 1344 vm_page_unlock_queues(); 1345 1346 KASSERT( 1347 p->object == backing_object, 1348 ("vm_object_qcollapse(): object mismatch") 1349 ); 1350 1351 /* 1352 * Destroy any associated swap 1353 */ 1354 if (backing_object->type == OBJT_SWAP) { 1355 swap_pager_freespace( 1356 backing_object, 1357 p->pindex, 1358 1 1359 ); 1360 } 1361 1362 if ( 1363 p->pindex < backing_offset_index || 1364 new_pindex >= object->size 1365 ) { 1366 /* 1367 * Page is out of the parent object's range, we 1368 * can simply destroy it. 1369 */ 1370 vm_page_lock_queues(); 1371 pmap_remove_all(p); 1372 vm_page_free(p); 1373 vm_page_unlock_queues(); 1374 p = next; 1375 continue; 1376 } 1377 1378 pp = vm_page_lookup(object, new_pindex); 1379 if ( 1380 pp != NULL || 1381 vm_pager_has_page(object, new_pindex, NULL, NULL) 1382 ) { 1383 /* 1384 * page already exists in parent OR swap exists 1385 * for this location in the parent. Destroy 1386 * the original page from the backing object. 1387 * 1388 * Leave the parent's page alone 1389 */ 1390 vm_page_lock_queues(); 1391 pmap_remove_all(p); 1392 vm_page_free(p); 1393 vm_page_unlock_queues(); 1394 p = next; 1395 continue; 1396 } 1397 1398 /* 1399 * Page does not exist in parent, rename the 1400 * page from the backing object to the main object. 1401 * 1402 * If the page was mapped to a process, it can remain 1403 * mapped through the rename. 1404 */ 1405 vm_page_lock_queues(); 1406 vm_page_rename(p, object, new_pindex); 1407 vm_page_unlock_queues(); 1408 /* page automatically made dirty by rename */ 1409 } 1410 p = next; 1411 } 1412 splx(s); 1413 return (r); 1414 } 1415 1416 1417 /* 1418 * this version of collapse allows the operation to occur earlier and 1419 * when paging_in_progress is true for an object... This is not a complete 1420 * operation, but should plug 99.9% of the rest of the leaks. 1421 */ 1422 static void 1423 vm_object_qcollapse(vm_object_t object) 1424 { 1425 vm_object_t backing_object = object->backing_object; 1426 1427 GIANT_REQUIRED; 1428 1429 if (backing_object->ref_count != 1) 1430 return; 1431 1432 backing_object->ref_count += 2; 1433 1434 vm_object_backing_scan(object, OBSC_COLLAPSE_NOWAIT); 1435 1436 backing_object->ref_count -= 2; 1437 } 1438 1439 /* 1440 * vm_object_collapse: 1441 * 1442 * Collapse an object with the object backing it. 1443 * Pages in the backing object are moved into the 1444 * parent, and the backing object is deallocated. 1445 */ 1446 void 1447 vm_object_collapse(vm_object_t object) 1448 { 1449 GIANT_REQUIRED; 1450 1451 while (TRUE) { 1452 vm_object_t backing_object; 1453 1454 /* 1455 * Verify that the conditions are right for collapse: 1456 * 1457 * The object exists and the backing object exists. 1458 */ 1459 if (object == NULL) 1460 break; 1461 1462 if ((backing_object = object->backing_object) == NULL) 1463 break; 1464 1465 /* 1466 * we check the backing object first, because it is most likely 1467 * not collapsable. 1468 */ 1469 if (backing_object->handle != NULL || 1470 (backing_object->type != OBJT_DEFAULT && 1471 backing_object->type != OBJT_SWAP) || 1472 (backing_object->flags & OBJ_DEAD) || 1473 object->handle != NULL || 1474 (object->type != OBJT_DEFAULT && 1475 object->type != OBJT_SWAP) || 1476 (object->flags & OBJ_DEAD)) { 1477 break; 1478 } 1479 1480 if ( 1481 object->paging_in_progress != 0 || 1482 backing_object->paging_in_progress != 0 1483 ) { 1484 vm_object_qcollapse(object); 1485 break; 1486 } 1487 1488 /* 1489 * We know that we can either collapse the backing object (if 1490 * the parent is the only reference to it) or (perhaps) have 1491 * the parent bypass the object if the parent happens to shadow 1492 * all the resident pages in the entire backing object. 1493 * 1494 * This is ignoring pager-backed pages such as swap pages. 1495 * vm_object_backing_scan fails the shadowing test in this 1496 * case. 1497 */ 1498 if (backing_object->ref_count == 1) { 1499 /* 1500 * If there is exactly one reference to the backing 1501 * object, we can collapse it into the parent. 1502 */ 1503 vm_object_backing_scan(object, OBSC_COLLAPSE_WAIT); 1504 1505 /* 1506 * Move the pager from backing_object to object. 1507 */ 1508 if (backing_object->type == OBJT_SWAP) { 1509 vm_object_pip_add(backing_object, 1); 1510 1511 /* 1512 * scrap the paging_offset junk and do a 1513 * discrete copy. This also removes major 1514 * assumptions about how the swap-pager 1515 * works from where it doesn't belong. The 1516 * new swapper is able to optimize the 1517 * destroy-source case. 1518 */ 1519 vm_object_pip_add(object, 1); 1520 swap_pager_copy( 1521 backing_object, 1522 object, 1523 OFF_TO_IDX(object->backing_object_offset), TRUE); 1524 vm_object_pip_wakeup(object); 1525 1526 vm_object_pip_wakeup(backing_object); 1527 } 1528 /* 1529 * Object now shadows whatever backing_object did. 1530 * Note that the reference to 1531 * backing_object->backing_object moves from within 1532 * backing_object to within object. 1533 */ 1534 TAILQ_REMOVE( 1535 &object->backing_object->shadow_head, 1536 object, 1537 shadow_list 1538 ); 1539 object->backing_object->shadow_count--; 1540 object->backing_object->generation++; 1541 if (backing_object->backing_object) { 1542 TAILQ_REMOVE( 1543 &backing_object->backing_object->shadow_head, 1544 backing_object, 1545 shadow_list 1546 ); 1547 backing_object->backing_object->shadow_count--; 1548 backing_object->backing_object->generation++; 1549 } 1550 object->backing_object = backing_object->backing_object; 1551 if (object->backing_object) { 1552 TAILQ_INSERT_TAIL( 1553 &object->backing_object->shadow_head, 1554 object, 1555 shadow_list 1556 ); 1557 object->backing_object->shadow_count++; 1558 object->backing_object->generation++; 1559 } 1560 1561 object->backing_object_offset += 1562 backing_object->backing_object_offset; 1563 1564 /* 1565 * Discard backing_object. 1566 * 1567 * Since the backing object has no pages, no pager left, 1568 * and no object references within it, all that is 1569 * necessary is to dispose of it. 1570 */ 1571 KASSERT(backing_object->ref_count == 1, ("backing_object %p was somehow re-referenced during collapse!", backing_object)); 1572 KASSERT(TAILQ_FIRST(&backing_object->memq) == NULL, ("backing_object %p somehow has left over pages during collapse!", backing_object)); 1573 1574 mtx_lock(&vm_object_list_mtx); 1575 TAILQ_REMOVE( 1576 &vm_object_list, 1577 backing_object, 1578 object_list 1579 ); 1580 mtx_unlock(&vm_object_list_mtx); 1581 1582 mtx_destroy(&backing_object->mtx); 1583 1584 uma_zfree(obj_zone, backing_object); 1585 1586 object_collapses++; 1587 } else { 1588 vm_object_t new_backing_object; 1589 1590 /* 1591 * If we do not entirely shadow the backing object, 1592 * there is nothing we can do so we give up. 1593 */ 1594 if (vm_object_backing_scan(object, OBSC_TEST_ALL_SHADOWED) == 0) { 1595 break; 1596 } 1597 1598 /* 1599 * Make the parent shadow the next object in the 1600 * chain. Deallocating backing_object will not remove 1601 * it, since its reference count is at least 2. 1602 */ 1603 TAILQ_REMOVE( 1604 &backing_object->shadow_head, 1605 object, 1606 shadow_list 1607 ); 1608 backing_object->shadow_count--; 1609 backing_object->generation++; 1610 1611 new_backing_object = backing_object->backing_object; 1612 if ((object->backing_object = new_backing_object) != NULL) { 1613 vm_object_reference(new_backing_object); 1614 TAILQ_INSERT_TAIL( 1615 &new_backing_object->shadow_head, 1616 object, 1617 shadow_list 1618 ); 1619 new_backing_object->shadow_count++; 1620 new_backing_object->generation++; 1621 object->backing_object_offset += 1622 backing_object->backing_object_offset; 1623 } 1624 1625 /* 1626 * Drop the reference count on backing_object. Since 1627 * its ref_count was at least 2, it will not vanish; 1628 * so we don't need to call vm_object_deallocate, but 1629 * we do anyway. 1630 */ 1631 vm_object_deallocate(backing_object); 1632 object_bypasses++; 1633 } 1634 1635 /* 1636 * Try again with this object's new backing object. 1637 */ 1638 } 1639 } 1640 1641 /* 1642 * vm_object_page_remove: [internal] 1643 * 1644 * Removes all physical pages in the specified 1645 * object range from the object's list of pages. 1646 * 1647 * The object must be locked. 1648 */ 1649 void 1650 vm_object_page_remove(vm_object_t object, vm_pindex_t start, vm_pindex_t end, boolean_t clean_only) 1651 { 1652 vm_page_t p, next; 1653 int all; 1654 1655 if (object == NULL || 1656 object->resident_page_count == 0) 1657 return; 1658 all = ((end == 0) && (start == 0)); 1659 1660 /* 1661 * Since physically-backed objects do not use managed pages, we can't 1662 * remove pages from the object (we must instead remove the page 1663 * references, and then destroy the object). 1664 */ 1665 KASSERT(object->type != OBJT_PHYS, ("attempt to remove pages from a physical object")); 1666 1667 vm_object_pip_add(object, 1); 1668 again: 1669 vm_page_lock_queues(); 1670 if ((p = TAILQ_FIRST(&object->memq)) != NULL) { 1671 if (p->pindex < start) { 1672 p = vm_page_splay(start, object->root); 1673 if ((object->root = p)->pindex < start) 1674 p = TAILQ_NEXT(p, listq); 1675 } 1676 } 1677 /* 1678 * Assert: the variable p is either (1) the page with the 1679 * least pindex greater than or equal to the parameter pindex 1680 * or (2) NULL. 1681 */ 1682 for (; 1683 p != NULL && (all || p->pindex < end); 1684 p = next) { 1685 next = TAILQ_NEXT(p, listq); 1686 1687 if (p->wire_count != 0) { 1688 pmap_remove_all(p); 1689 if (!clean_only) 1690 p->valid = 0; 1691 continue; 1692 } 1693 if (vm_page_sleep_if_busy(p, TRUE, "vmopar")) 1694 goto again; 1695 if (clean_only && p->valid) { 1696 vm_page_test_dirty(p); 1697 if (p->valid & p->dirty) 1698 continue; 1699 } 1700 vm_page_busy(p); 1701 pmap_remove_all(p); 1702 vm_page_free(p); 1703 } 1704 vm_page_unlock_queues(); 1705 vm_object_pip_wakeup(object); 1706 } 1707 1708 /* 1709 * Routine: vm_object_coalesce 1710 * Function: Coalesces two objects backing up adjoining 1711 * regions of memory into a single object. 1712 * 1713 * returns TRUE if objects were combined. 1714 * 1715 * NOTE: Only works at the moment if the second object is NULL - 1716 * if it's not, which object do we lock first? 1717 * 1718 * Parameters: 1719 * prev_object First object to coalesce 1720 * prev_offset Offset into prev_object 1721 * next_object Second object into coalesce 1722 * next_offset Offset into next_object 1723 * 1724 * prev_size Size of reference to prev_object 1725 * next_size Size of reference to next_object 1726 * 1727 * Conditions: 1728 * The object must *not* be locked. 1729 */ 1730 boolean_t 1731 vm_object_coalesce(vm_object_t prev_object, vm_pindex_t prev_pindex, 1732 vm_size_t prev_size, vm_size_t next_size) 1733 { 1734 vm_pindex_t next_pindex; 1735 1736 if (prev_object == NULL) 1737 return (TRUE); 1738 vm_object_lock(prev_object); 1739 if (prev_object->type != OBJT_DEFAULT && 1740 prev_object->type != OBJT_SWAP) { 1741 vm_object_unlock(prev_object); 1742 return (FALSE); 1743 } 1744 1745 /* 1746 * Try to collapse the object first 1747 */ 1748 vm_object_collapse(prev_object); 1749 1750 /* 1751 * Can't coalesce if: . more than one reference . paged out . shadows 1752 * another object . has a copy elsewhere (any of which mean that the 1753 * pages not mapped to prev_entry may be in use anyway) 1754 */ 1755 if (prev_object->backing_object != NULL) { 1756 vm_object_unlock(prev_object); 1757 return (FALSE); 1758 } 1759 1760 prev_size >>= PAGE_SHIFT; 1761 next_size >>= PAGE_SHIFT; 1762 next_pindex = prev_pindex + prev_size; 1763 1764 if ((prev_object->ref_count > 1) && 1765 (prev_object->size != next_pindex)) { 1766 vm_object_unlock(prev_object); 1767 return (FALSE); 1768 } 1769 1770 /* 1771 * Remove any pages that may still be in the object from a previous 1772 * deallocation. 1773 */ 1774 if (next_pindex < prev_object->size) { 1775 vm_object_page_remove(prev_object, 1776 next_pindex, 1777 next_pindex + next_size, FALSE); 1778 if (prev_object->type == OBJT_SWAP) 1779 swap_pager_freespace(prev_object, 1780 next_pindex, next_size); 1781 } 1782 1783 /* 1784 * Extend the object if necessary. 1785 */ 1786 if (next_pindex + next_size > prev_object->size) 1787 prev_object->size = next_pindex + next_size; 1788 1789 vm_object_unlock(prev_object); 1790 return (TRUE); 1791 } 1792 1793 void 1794 vm_object_set_writeable_dirty(vm_object_t object) 1795 { 1796 struct vnode *vp; 1797 1798 vm_object_set_flag(object, OBJ_WRITEABLE|OBJ_MIGHTBEDIRTY); 1799 if (object->type == OBJT_VNODE && 1800 (vp = (struct vnode *)object->handle) != NULL) { 1801 VI_LOCK(vp); 1802 if ((vp->v_iflag & VI_OBJDIRTY) == 0) 1803 vp->v_iflag |= VI_OBJDIRTY; 1804 VI_UNLOCK(vp); 1805 } 1806 } 1807 1808 #include "opt_ddb.h" 1809 #ifdef DDB 1810 #include <sys/kernel.h> 1811 1812 #include <sys/cons.h> 1813 1814 #include <ddb/ddb.h> 1815 1816 static int 1817 _vm_object_in_map(vm_map_t map, vm_object_t object, vm_map_entry_t entry) 1818 { 1819 vm_map_t tmpm; 1820 vm_map_entry_t tmpe; 1821 vm_object_t obj; 1822 int entcount; 1823 1824 if (map == 0) 1825 return 0; 1826 1827 if (entry == 0) { 1828 tmpe = map->header.next; 1829 entcount = map->nentries; 1830 while (entcount-- && (tmpe != &map->header)) { 1831 if (_vm_object_in_map(map, object, tmpe)) { 1832 return 1; 1833 } 1834 tmpe = tmpe->next; 1835 } 1836 } else if (entry->eflags & MAP_ENTRY_IS_SUB_MAP) { 1837 tmpm = entry->object.sub_map; 1838 tmpe = tmpm->header.next; 1839 entcount = tmpm->nentries; 1840 while (entcount-- && tmpe != &tmpm->header) { 1841 if (_vm_object_in_map(tmpm, object, tmpe)) { 1842 return 1; 1843 } 1844 tmpe = tmpe->next; 1845 } 1846 } else if ((obj = entry->object.vm_object) != NULL) { 1847 for (; obj; obj = obj->backing_object) 1848 if (obj == object) { 1849 return 1; 1850 } 1851 } 1852 return 0; 1853 } 1854 1855 static int 1856 vm_object_in_map(vm_object_t object) 1857 { 1858 struct proc *p; 1859 1860 /* sx_slock(&allproc_lock); */ 1861 LIST_FOREACH(p, &allproc, p_list) { 1862 if (!p->p_vmspace /* || (p->p_flag & (P_SYSTEM|P_WEXIT)) */) 1863 continue; 1864 if (_vm_object_in_map(&p->p_vmspace->vm_map, object, 0)) { 1865 /* sx_sunlock(&allproc_lock); */ 1866 return 1; 1867 } 1868 } 1869 /* sx_sunlock(&allproc_lock); */ 1870 if (_vm_object_in_map(kernel_map, object, 0)) 1871 return 1; 1872 if (_vm_object_in_map(kmem_map, object, 0)) 1873 return 1; 1874 if (_vm_object_in_map(pager_map, object, 0)) 1875 return 1; 1876 if (_vm_object_in_map(buffer_map, object, 0)) 1877 return 1; 1878 return 0; 1879 } 1880 1881 DB_SHOW_COMMAND(vmochk, vm_object_check) 1882 { 1883 vm_object_t object; 1884 1885 /* 1886 * make sure that internal objs are in a map somewhere 1887 * and none have zero ref counts. 1888 */ 1889 TAILQ_FOREACH(object, &vm_object_list, object_list) { 1890 if (object->handle == NULL && 1891 (object->type == OBJT_DEFAULT || object->type == OBJT_SWAP)) { 1892 if (object->ref_count == 0) { 1893 db_printf("vmochk: internal obj has zero ref count: %ld\n", 1894 (long)object->size); 1895 } 1896 if (!vm_object_in_map(object)) { 1897 db_printf( 1898 "vmochk: internal obj is not in a map: " 1899 "ref: %d, size: %lu: 0x%lx, backing_object: %p\n", 1900 object->ref_count, (u_long)object->size, 1901 (u_long)object->size, 1902 (void *)object->backing_object); 1903 } 1904 } 1905 } 1906 } 1907 1908 /* 1909 * vm_object_print: [ debug ] 1910 */ 1911 DB_SHOW_COMMAND(object, vm_object_print_static) 1912 { 1913 /* XXX convert args. */ 1914 vm_object_t object = (vm_object_t)addr; 1915 boolean_t full = have_addr; 1916 1917 vm_page_t p; 1918 1919 /* XXX count is an (unused) arg. Avoid shadowing it. */ 1920 #define count was_count 1921 1922 int count; 1923 1924 if (object == NULL) 1925 return; 1926 1927 db_iprintf( 1928 "Object %p: type=%d, size=0x%jx, res=%d, ref=%d, flags=0x%x\n", 1929 object, (int)object->type, (uintmax_t)object->size, 1930 object->resident_page_count, object->ref_count, object->flags); 1931 db_iprintf(" sref=%d, backing_object(%d)=(%p)+0x%jx\n", 1932 object->shadow_count, 1933 object->backing_object ? object->backing_object->ref_count : 0, 1934 object->backing_object, (uintmax_t)object->backing_object_offset); 1935 1936 if (!full) 1937 return; 1938 1939 db_indent += 2; 1940 count = 0; 1941 TAILQ_FOREACH(p, &object->memq, listq) { 1942 if (count == 0) 1943 db_iprintf("memory:="); 1944 else if (count == 6) { 1945 db_printf("\n"); 1946 db_iprintf(" ..."); 1947 count = 0; 1948 } else 1949 db_printf(","); 1950 count++; 1951 1952 db_printf("(off=0x%jx,page=0x%jx)", 1953 (uintmax_t)p->pindex, (uintmax_t)VM_PAGE_TO_PHYS(p)); 1954 } 1955 if (count != 0) 1956 db_printf("\n"); 1957 db_indent -= 2; 1958 } 1959 1960 /* XXX. */ 1961 #undef count 1962 1963 /* XXX need this non-static entry for calling from vm_map_print. */ 1964 void 1965 vm_object_print( 1966 /* db_expr_t */ long addr, 1967 boolean_t have_addr, 1968 /* db_expr_t */ long count, 1969 char *modif) 1970 { 1971 vm_object_print_static(addr, have_addr, count, modif); 1972 } 1973 1974 DB_SHOW_COMMAND(vmopag, vm_object_print_pages) 1975 { 1976 vm_object_t object; 1977 int nl = 0; 1978 int c; 1979 1980 TAILQ_FOREACH(object, &vm_object_list, object_list) { 1981 vm_pindex_t idx, fidx; 1982 vm_pindex_t osize; 1983 vm_paddr_t pa = -1, padiff; 1984 int rcount; 1985 vm_page_t m; 1986 1987 db_printf("new object: %p\n", (void *)object); 1988 if (nl > 18) { 1989 c = cngetc(); 1990 if (c != ' ') 1991 return; 1992 nl = 0; 1993 } 1994 nl++; 1995 rcount = 0; 1996 fidx = 0; 1997 osize = object->size; 1998 if (osize > 128) 1999 osize = 128; 2000 for (idx = 0; idx < osize; idx++) { 2001 m = vm_page_lookup(object, idx); 2002 if (m == NULL) { 2003 if (rcount) { 2004 db_printf(" index(%ld)run(%d)pa(0x%lx)\n", 2005 (long)fidx, rcount, (long)pa); 2006 if (nl > 18) { 2007 c = cngetc(); 2008 if (c != ' ') 2009 return; 2010 nl = 0; 2011 } 2012 nl++; 2013 rcount = 0; 2014 } 2015 continue; 2016 } 2017 2018 2019 if (rcount && 2020 (VM_PAGE_TO_PHYS(m) == pa + rcount * PAGE_SIZE)) { 2021 ++rcount; 2022 continue; 2023 } 2024 if (rcount) { 2025 padiff = pa + rcount * PAGE_SIZE - VM_PAGE_TO_PHYS(m); 2026 padiff >>= PAGE_SHIFT; 2027 padiff &= PQ_L2_MASK; 2028 if (padiff == 0) { 2029 pa = VM_PAGE_TO_PHYS(m) - rcount * PAGE_SIZE; 2030 ++rcount; 2031 continue; 2032 } 2033 db_printf(" index(%ld)run(%d)pa(0x%lx)", 2034 (long)fidx, rcount, (long)pa); 2035 db_printf("pd(%ld)\n", (long)padiff); 2036 if (nl > 18) { 2037 c = cngetc(); 2038 if (c != ' ') 2039 return; 2040 nl = 0; 2041 } 2042 nl++; 2043 } 2044 fidx = idx; 2045 pa = VM_PAGE_TO_PHYS(m); 2046 rcount = 1; 2047 } 2048 if (rcount) { 2049 db_printf(" index(%ld)run(%d)pa(0x%lx)\n", 2050 (long)fidx, rcount, (long)pa); 2051 if (nl > 18) { 2052 c = cngetc(); 2053 if (c != ' ') 2054 return; 2055 nl = 0; 2056 } 2057 nl++; 2058 } 2059 } 2060 } 2061 #endif /* DDB */ 2062