vm_object.c revision 207452
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 * 4. Neither the name of the University nor the names of its contributors 17 * may be used to endorse or promote products derived from this software 18 * without specific prior written permission. 19 * 20 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 21 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 22 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 23 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 24 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 25 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 26 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 27 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 28 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 29 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 30 * SUCH DAMAGE. 31 * 32 * from: @(#)vm_object.c 8.5 (Berkeley) 3/22/94 33 * 34 * 35 * Copyright (c) 1987, 1990 Carnegie-Mellon University. 36 * All rights reserved. 37 * 38 * Authors: Avadis Tevanian, Jr., Michael Wayne Young 39 * 40 * Permission to use, copy, modify and distribute this software and 41 * its documentation is hereby granted, provided that both the copyright 42 * notice and this permission notice appear in all copies of the 43 * software, derivative works or modified versions, and any portions 44 * thereof, and that both notices appear in supporting documentation. 45 * 46 * CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS" 47 * CONDITION. CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND 48 * FOR ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE. 49 * 50 * Carnegie Mellon requests users of this software to return to 51 * 52 * Software Distribution Coordinator or Software.Distribution@CS.CMU.EDU 53 * School of Computer Science 54 * Carnegie Mellon University 55 * Pittsburgh PA 15213-3890 56 * 57 * any improvements or extensions that they make and grant Carnegie the 58 * rights to redistribute these changes. 59 */ 60 61/* 62 * Virtual memory object module. 63 */ 64 65#include <sys/cdefs.h> 66__FBSDID("$FreeBSD: head/sys/vm/vm_object.c 207452 2010-04-30 22:31:37Z kmacy $"); 67 68#include "opt_vm.h" 69 70#include <sys/param.h> 71#include <sys/systm.h> 72#include <sys/lock.h> 73#include <sys/mman.h> 74#include <sys/mount.h> 75#include <sys/kernel.h> 76#include <sys/sysctl.h> 77#include <sys/mutex.h> 78#include <sys/proc.h> /* for curproc, pageproc */ 79#include <sys/socket.h> 80#include <sys/resourcevar.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/vm_reserv.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 */ 107static int msync_flush_flags = MSYNC_FLUSH_HARDSEQ | MSYNC_FLUSH_SOFTSEQ; 108SYSCTL_INT(_vm, OID_AUTO, msync_flush_flags, CTLFLAG_RW, &msync_flush_flags, 0, 109 "Enable sequential iteration optimization"); 110 111static int old_msync; 112SYSCTL_INT(_vm, OID_AUTO, old_msync, CTLFLAG_RW, &old_msync, 0, 113 "Use old (insecure) msync behavior"); 114 115static void vm_object_qcollapse(vm_object_t object); 116static int vm_object_page_collect_flush(vm_object_t object, vm_page_t p, int curgeneration, int pagerflags); 117static void vm_object_vndeallocate(vm_object_t object); 118 119/* 120 * Virtual memory objects maintain the actual data 121 * associated with allocated virtual memory. A given 122 * page of memory exists within exactly one object. 123 * 124 * An object is only deallocated when all "references" 125 * are given up. Only one "reference" to a given 126 * region of an object should be writeable. 127 * 128 * Associated with each object is a list of all resident 129 * memory pages belonging to that object; this list is 130 * maintained by the "vm_page" module, and locked by the object's 131 * lock. 132 * 133 * Each object also records a "pager" routine which is 134 * used to retrieve (and store) pages to the proper backing 135 * storage. In addition, objects may be backed by other 136 * objects from which they were virtual-copied. 137 * 138 * The only items within the object structure which are 139 * modified after time of creation are: 140 * reference count locked by object's lock 141 * pager routine locked by object's lock 142 * 143 */ 144 145struct object_q vm_object_list; 146struct mtx vm_object_list_mtx; /* lock for object list and count */ 147 148struct vm_object kernel_object_store; 149struct vm_object kmem_object_store; 150 151SYSCTL_NODE(_vm_stats, OID_AUTO, object, CTLFLAG_RD, 0, "VM object stats"); 152 153static long object_collapses; 154SYSCTL_LONG(_vm_stats_object, OID_AUTO, collapses, CTLFLAG_RD, 155 &object_collapses, 0, "VM object collapses"); 156 157static long object_bypasses; 158SYSCTL_LONG(_vm_stats_object, OID_AUTO, bypasses, CTLFLAG_RD, 159 &object_bypasses, 0, "VM object bypasses"); 160 161static uma_zone_t obj_zone; 162 163static int vm_object_zinit(void *mem, int size, int flags); 164 165#ifdef INVARIANTS 166static void vm_object_zdtor(void *mem, int size, void *arg); 167 168static void 169vm_object_zdtor(void *mem, int size, void *arg) 170{ 171 vm_object_t object; 172 173 object = (vm_object_t)mem; 174 KASSERT(TAILQ_EMPTY(&object->memq), 175 ("object %p has resident pages", 176 object)); 177#if VM_NRESERVLEVEL > 0 178 KASSERT(LIST_EMPTY(&object->rvq), 179 ("object %p has reservations", 180 object)); 181#endif 182 KASSERT(object->cache == NULL, 183 ("object %p has cached pages", 184 object)); 185 KASSERT(object->paging_in_progress == 0, 186 ("object %p paging_in_progress = %d", 187 object, object->paging_in_progress)); 188 KASSERT(object->resident_page_count == 0, 189 ("object %p resident_page_count = %d", 190 object, object->resident_page_count)); 191 KASSERT(object->shadow_count == 0, 192 ("object %p shadow_count = %d", 193 object, object->shadow_count)); 194} 195#endif 196 197static int 198vm_object_zinit(void *mem, int size, int flags) 199{ 200 vm_object_t object; 201 202 object = (vm_object_t)mem; 203 bzero(&object->mtx, sizeof(object->mtx)); 204 VM_OBJECT_LOCK_INIT(object, "standard object"); 205 206 /* These are true for any object that has been freed */ 207 object->paging_in_progress = 0; 208 object->resident_page_count = 0; 209 object->shadow_count = 0; 210 return (0); 211} 212 213void 214_vm_object_allocate(objtype_t type, vm_pindex_t size, vm_object_t object) 215{ 216 217 TAILQ_INIT(&object->memq); 218 LIST_INIT(&object->shadow_head); 219 220 object->root = NULL; 221 object->type = type; 222 object->size = size; 223 object->generation = 1; 224 object->ref_count = 1; 225 object->memattr = VM_MEMATTR_DEFAULT; 226 object->flags = 0; 227 object->uip = NULL; 228 object->charge = 0; 229 if ((object->type == OBJT_DEFAULT) || (object->type == OBJT_SWAP)) 230 object->flags = OBJ_ONEMAPPING; 231 object->pg_color = 0; 232 object->handle = NULL; 233 object->backing_object = NULL; 234 object->backing_object_offset = (vm_ooffset_t) 0; 235#if VM_NRESERVLEVEL > 0 236 LIST_INIT(&object->rvq); 237#endif 238 object->cache = NULL; 239 240 mtx_lock(&vm_object_list_mtx); 241 TAILQ_INSERT_TAIL(&vm_object_list, object, object_list); 242 mtx_unlock(&vm_object_list_mtx); 243} 244 245/* 246 * vm_object_init: 247 * 248 * Initialize the VM objects module. 249 */ 250void 251vm_object_init(void) 252{ 253 TAILQ_INIT(&vm_object_list); 254 mtx_init(&vm_object_list_mtx, "vm object_list", NULL, MTX_DEF); 255 256 VM_OBJECT_LOCK_INIT(&kernel_object_store, "kernel object"); 257 _vm_object_allocate(OBJT_PHYS, OFF_TO_IDX(VM_MAX_KERNEL_ADDRESS - VM_MIN_KERNEL_ADDRESS), 258 kernel_object); 259#if VM_NRESERVLEVEL > 0 260 kernel_object->flags |= OBJ_COLORED; 261 kernel_object->pg_color = (u_short)atop(VM_MIN_KERNEL_ADDRESS); 262#endif 263 264 VM_OBJECT_LOCK_INIT(&kmem_object_store, "kmem object"); 265 _vm_object_allocate(OBJT_PHYS, OFF_TO_IDX(VM_MAX_KERNEL_ADDRESS - VM_MIN_KERNEL_ADDRESS), 266 kmem_object); 267#if VM_NRESERVLEVEL > 0 268 kmem_object->flags |= OBJ_COLORED; 269 kmem_object->pg_color = (u_short)atop(VM_MIN_KERNEL_ADDRESS); 270#endif 271 272 /* 273 * The lock portion of struct vm_object must be type stable due 274 * to vm_pageout_fallback_object_lock locking a vm object 275 * without holding any references to it. 276 */ 277 obj_zone = uma_zcreate("VM OBJECT", sizeof (struct vm_object), NULL, 278#ifdef INVARIANTS 279 vm_object_zdtor, 280#else 281 NULL, 282#endif 283 vm_object_zinit, NULL, UMA_ALIGN_PTR, UMA_ZONE_VM|UMA_ZONE_NOFREE); 284} 285 286void 287vm_object_clear_flag(vm_object_t object, u_short bits) 288{ 289 290 VM_OBJECT_LOCK_ASSERT(object, MA_OWNED); 291 object->flags &= ~bits; 292} 293 294/* 295 * Sets the default memory attribute for the specified object. Pages 296 * that are allocated to this object are by default assigned this memory 297 * attribute. 298 * 299 * Presently, this function must be called before any pages are allocated 300 * to the object. In the future, this requirement may be relaxed for 301 * "default" and "swap" objects. 302 */ 303int 304vm_object_set_memattr(vm_object_t object, vm_memattr_t memattr) 305{ 306 307 VM_OBJECT_LOCK_ASSERT(object, MA_OWNED); 308 switch (object->type) { 309 case OBJT_DEFAULT: 310 case OBJT_DEVICE: 311 case OBJT_PHYS: 312 case OBJT_SG: 313 case OBJT_SWAP: 314 case OBJT_VNODE: 315 if (!TAILQ_EMPTY(&object->memq)) 316 return (KERN_FAILURE); 317 break; 318 case OBJT_DEAD: 319 return (KERN_INVALID_ARGUMENT); 320 } 321 object->memattr = memattr; 322 return (KERN_SUCCESS); 323} 324 325void 326vm_object_pip_add(vm_object_t object, short i) 327{ 328 329 VM_OBJECT_LOCK_ASSERT(object, MA_OWNED); 330 object->paging_in_progress += i; 331} 332 333void 334vm_object_pip_subtract(vm_object_t object, short i) 335{ 336 337 VM_OBJECT_LOCK_ASSERT(object, MA_OWNED); 338 object->paging_in_progress -= i; 339} 340 341void 342vm_object_pip_wakeup(vm_object_t object) 343{ 344 345 VM_OBJECT_LOCK_ASSERT(object, MA_OWNED); 346 object->paging_in_progress--; 347 if ((object->flags & OBJ_PIPWNT) && object->paging_in_progress == 0) { 348 vm_object_clear_flag(object, OBJ_PIPWNT); 349 wakeup(object); 350 } 351} 352 353void 354vm_object_pip_wakeupn(vm_object_t object, short i) 355{ 356 357 VM_OBJECT_LOCK_ASSERT(object, MA_OWNED); 358 if (i) 359 object->paging_in_progress -= i; 360 if ((object->flags & OBJ_PIPWNT) && object->paging_in_progress == 0) { 361 vm_object_clear_flag(object, OBJ_PIPWNT); 362 wakeup(object); 363 } 364} 365 366void 367vm_object_pip_wait(vm_object_t object, char *waitid) 368{ 369 370 VM_OBJECT_LOCK_ASSERT(object, MA_OWNED); 371 while (object->paging_in_progress) { 372 object->flags |= OBJ_PIPWNT; 373 msleep(object, VM_OBJECT_MTX(object), PVM, waitid, 0); 374 } 375} 376 377/* 378 * vm_object_allocate: 379 * 380 * Returns a new object with the given size. 381 */ 382vm_object_t 383vm_object_allocate(objtype_t type, vm_pindex_t size) 384{ 385 vm_object_t object; 386 387 object = (vm_object_t)uma_zalloc(obj_zone, M_WAITOK); 388 _vm_object_allocate(type, size, object); 389 return (object); 390} 391 392 393/* 394 * vm_object_reference: 395 * 396 * Gets another reference to the given object. Note: OBJ_DEAD 397 * objects can be referenced during final cleaning. 398 */ 399void 400vm_object_reference(vm_object_t object) 401{ 402 if (object == NULL) 403 return; 404 VM_OBJECT_LOCK(object); 405 vm_object_reference_locked(object); 406 VM_OBJECT_UNLOCK(object); 407} 408 409/* 410 * vm_object_reference_locked: 411 * 412 * Gets another reference to the given object. 413 * 414 * The object must be locked. 415 */ 416void 417vm_object_reference_locked(vm_object_t object) 418{ 419 struct vnode *vp; 420 421 VM_OBJECT_LOCK_ASSERT(object, MA_OWNED); 422 object->ref_count++; 423 if (object->type == OBJT_VNODE) { 424 vp = object->handle; 425 vref(vp); 426 } 427} 428 429/* 430 * Handle deallocating an object of type OBJT_VNODE. 431 */ 432static void 433vm_object_vndeallocate(vm_object_t object) 434{ 435 struct vnode *vp = (struct vnode *) object->handle; 436 437 VFS_ASSERT_GIANT(vp->v_mount); 438 VM_OBJECT_LOCK_ASSERT(object, MA_OWNED); 439 KASSERT(object->type == OBJT_VNODE, 440 ("vm_object_vndeallocate: not a vnode object")); 441 KASSERT(vp != NULL, ("vm_object_vndeallocate: missing vp")); 442#ifdef INVARIANTS 443 if (object->ref_count == 0) { 444 vprint("vm_object_vndeallocate", vp); 445 panic("vm_object_vndeallocate: bad object reference count"); 446 } 447#endif 448 449 object->ref_count--; 450 if (object->ref_count == 0) { 451 mp_fixme("Unlocked vflag access."); 452 vp->v_vflag &= ~VV_TEXT; 453 } 454 VM_OBJECT_UNLOCK(object); 455 /* 456 * vrele may need a vop lock 457 */ 458 vrele(vp); 459} 460 461/* 462 * vm_object_deallocate: 463 * 464 * Release a reference to the specified object, 465 * gained either through a vm_object_allocate 466 * or a vm_object_reference call. When all references 467 * are gone, storage associated with this object 468 * may be relinquished. 469 * 470 * No object may be locked. 471 */ 472void 473vm_object_deallocate(vm_object_t object) 474{ 475 vm_object_t temp; 476 477 while (object != NULL) { 478 int vfslocked; 479 480 vfslocked = 0; 481 restart: 482 VM_OBJECT_LOCK(object); 483 if (object->type == OBJT_VNODE) { 484 struct vnode *vp = (struct vnode *) object->handle; 485 486 /* 487 * Conditionally acquire Giant for a vnode-backed 488 * object. We have to be careful since the type of 489 * a vnode object can change while the object is 490 * unlocked. 491 */ 492 if (VFS_NEEDSGIANT(vp->v_mount) && !vfslocked) { 493 vfslocked = 1; 494 if (!mtx_trylock(&Giant)) { 495 VM_OBJECT_UNLOCK(object); 496 mtx_lock(&Giant); 497 goto restart; 498 } 499 } 500 vm_object_vndeallocate(object); 501 VFS_UNLOCK_GIANT(vfslocked); 502 return; 503 } else 504 /* 505 * This is to handle the case that the object 506 * changed type while we dropped its lock to 507 * obtain Giant. 508 */ 509 VFS_UNLOCK_GIANT(vfslocked); 510 511 KASSERT(object->ref_count != 0, 512 ("vm_object_deallocate: object deallocated too many times: %d", object->type)); 513 514 /* 515 * If the reference count goes to 0 we start calling 516 * vm_object_terminate() on the object chain. 517 * A ref count of 1 may be a special case depending on the 518 * shadow count being 0 or 1. 519 */ 520 object->ref_count--; 521 if (object->ref_count > 1) { 522 VM_OBJECT_UNLOCK(object); 523 return; 524 } else if (object->ref_count == 1) { 525 if (object->shadow_count == 0 && 526 object->handle == NULL && 527 (object->type == OBJT_DEFAULT || 528 object->type == OBJT_SWAP)) { 529 vm_object_set_flag(object, OBJ_ONEMAPPING); 530 } else if ((object->shadow_count == 1) && 531 (object->handle == NULL) && 532 (object->type == OBJT_DEFAULT || 533 object->type == OBJT_SWAP)) { 534 vm_object_t robject; 535 536 robject = LIST_FIRST(&object->shadow_head); 537 KASSERT(robject != NULL, 538 ("vm_object_deallocate: ref_count: %d, shadow_count: %d", 539 object->ref_count, 540 object->shadow_count)); 541 if (!VM_OBJECT_TRYLOCK(robject)) { 542 /* 543 * Avoid a potential deadlock. 544 */ 545 object->ref_count++; 546 VM_OBJECT_UNLOCK(object); 547 /* 548 * More likely than not the thread 549 * holding robject's lock has lower 550 * priority than the current thread. 551 * Let the lower priority thread run. 552 */ 553 pause("vmo_de", 1); 554 continue; 555 } 556 /* 557 * Collapse object into its shadow unless its 558 * shadow is dead. In that case, object will 559 * be deallocated by the thread that is 560 * deallocating its shadow. 561 */ 562 if ((robject->flags & OBJ_DEAD) == 0 && 563 (robject->handle == NULL) && 564 (robject->type == OBJT_DEFAULT || 565 robject->type == OBJT_SWAP)) { 566 567 robject->ref_count++; 568retry: 569 if (robject->paging_in_progress) { 570 VM_OBJECT_UNLOCK(object); 571 vm_object_pip_wait(robject, 572 "objde1"); 573 temp = robject->backing_object; 574 if (object == temp) { 575 VM_OBJECT_LOCK(object); 576 goto retry; 577 } 578 } else if (object->paging_in_progress) { 579 VM_OBJECT_UNLOCK(robject); 580 object->flags |= OBJ_PIPWNT; 581 msleep(object, 582 VM_OBJECT_MTX(object), 583 PDROP | PVM, "objde2", 0); 584 VM_OBJECT_LOCK(robject); 585 temp = robject->backing_object; 586 if (object == temp) { 587 VM_OBJECT_LOCK(object); 588 goto retry; 589 } 590 } else 591 VM_OBJECT_UNLOCK(object); 592 593 if (robject->ref_count == 1) { 594 robject->ref_count--; 595 object = robject; 596 goto doterm; 597 } 598 object = robject; 599 vm_object_collapse(object); 600 VM_OBJECT_UNLOCK(object); 601 continue; 602 } 603 VM_OBJECT_UNLOCK(robject); 604 } 605 VM_OBJECT_UNLOCK(object); 606 return; 607 } 608doterm: 609 temp = object->backing_object; 610 if (temp != NULL) { 611 VM_OBJECT_LOCK(temp); 612 LIST_REMOVE(object, shadow_list); 613 temp->shadow_count--; 614 temp->generation++; 615 VM_OBJECT_UNLOCK(temp); 616 object->backing_object = NULL; 617 } 618 /* 619 * Don't double-terminate, we could be in a termination 620 * recursion due to the terminate having to sync data 621 * to disk. 622 */ 623 if ((object->flags & OBJ_DEAD) == 0) 624 vm_object_terminate(object); 625 else 626 VM_OBJECT_UNLOCK(object); 627 object = temp; 628 } 629} 630 631/* 632 * vm_object_destroy removes the object from the global object list 633 * and frees the space for the object. 634 */ 635void 636vm_object_destroy(vm_object_t object) 637{ 638 639 /* 640 * Remove the object from the global object list. 641 */ 642 mtx_lock(&vm_object_list_mtx); 643 TAILQ_REMOVE(&vm_object_list, object, object_list); 644 mtx_unlock(&vm_object_list_mtx); 645 646 /* 647 * Release the allocation charge. 648 */ 649 if (object->uip != NULL) { 650 KASSERT(object->type == OBJT_DEFAULT || 651 object->type == OBJT_SWAP, 652 ("vm_object_terminate: non-swap obj %p has uip", 653 object)); 654 swap_release_by_uid(object->charge, object->uip); 655 object->charge = 0; 656 uifree(object->uip); 657 object->uip = NULL; 658 } 659 660 /* 661 * Free the space for the object. 662 */ 663 uma_zfree(obj_zone, object); 664} 665 666/* 667 * vm_object_terminate actually destroys the specified object, freeing 668 * up all previously used resources. 669 * 670 * The object must be locked. 671 * This routine may block. 672 */ 673void 674vm_object_terminate(vm_object_t object) 675{ 676 vm_page_t p; 677 678 VM_OBJECT_LOCK_ASSERT(object, MA_OWNED); 679 680 /* 681 * Make sure no one uses us. 682 */ 683 vm_object_set_flag(object, OBJ_DEAD); 684 685 /* 686 * wait for the pageout daemon to be done with the object 687 */ 688 vm_object_pip_wait(object, "objtrm"); 689 690 KASSERT(!object->paging_in_progress, 691 ("vm_object_terminate: pageout in progress")); 692 693 /* 694 * Clean and free the pages, as appropriate. All references to the 695 * object are gone, so we don't need to lock it. 696 */ 697 if (object->type == OBJT_VNODE) { 698 struct vnode *vp = (struct vnode *)object->handle; 699 700 /* 701 * Clean pages and flush buffers. 702 */ 703 vm_object_page_clean(object, 0, 0, OBJPC_SYNC); 704 VM_OBJECT_UNLOCK(object); 705 706 vinvalbuf(vp, V_SAVE, 0, 0); 707 708 VM_OBJECT_LOCK(object); 709 } 710 711 KASSERT(object->ref_count == 0, 712 ("vm_object_terminate: object with references, ref_count=%d", 713 object->ref_count)); 714 715 /* 716 * Now free any remaining pages. For internal objects, this also 717 * removes them from paging queues. Don't free wired pages, just 718 * remove them from the object. 719 */ 720 while ((p = TAILQ_FIRST(&object->memq)) != NULL) { 721 KASSERT(!p->busy && (p->oflags & VPO_BUSY) == 0, 722 ("vm_object_terminate: freeing busy page %p " 723 "p->busy = %d, p->oflags %x\n", p, p->busy, p->oflags)); 724 vm_page_lock(p); 725 vm_page_lock_queues(); 726 if (p->wire_count == 0) { 727 vm_page_free(p); 728 cnt.v_pfree++; 729 } else { 730 vm_page_remove(p); 731 } 732 vm_page_unlock_queues(); 733 vm_page_unlock(p); 734 } 735 736#if VM_NRESERVLEVEL > 0 737 if (__predict_false(!LIST_EMPTY(&object->rvq))) 738 vm_reserv_break_all(object); 739#endif 740 if (__predict_false(object->cache != NULL)) 741 vm_page_cache_free(object, 0, 0); 742 743 /* 744 * Let the pager know object is dead. 745 */ 746 vm_pager_deallocate(object); 747 VM_OBJECT_UNLOCK(object); 748 749 vm_object_destroy(object); 750} 751 752/* 753 * vm_object_page_clean 754 * 755 * Clean all dirty pages in the specified range of object. Leaves page 756 * on whatever queue it is currently on. If NOSYNC is set then do not 757 * write out pages with VPO_NOSYNC set (originally comes from MAP_NOSYNC), 758 * leaving the object dirty. 759 * 760 * When stuffing pages asynchronously, allow clustering. XXX we need a 761 * synchronous clustering mode implementation. 762 * 763 * Odd semantics: if start == end, we clean everything. 764 * 765 * The object must be locked. 766 */ 767void 768vm_object_page_clean(vm_object_t object, vm_pindex_t start, vm_pindex_t end, int flags) 769{ 770 vm_page_t p, np; 771 vm_pindex_t tstart, tend; 772 vm_pindex_t pi; 773 int clearobjflags; 774 int pagerflags; 775 int curgeneration; 776 777 mtx_assert(&vm_page_queue_mtx, MA_NOTOWNED); 778 VM_OBJECT_LOCK_ASSERT(object, MA_OWNED); 779 if ((object->flags & OBJ_MIGHTBEDIRTY) == 0) 780 return; 781 KASSERT(object->type == OBJT_VNODE, ("Not a vnode object")); 782 783 pagerflags = (flags & (OBJPC_SYNC | OBJPC_INVAL)) ? VM_PAGER_PUT_SYNC : VM_PAGER_CLUSTER_OK; 784 pagerflags |= (flags & OBJPC_INVAL) ? VM_PAGER_PUT_INVAL : 0; 785 786 vm_object_set_flag(object, OBJ_CLEANING); 787 788 tstart = start; 789 if (end == 0) { 790 tend = object->size; 791 } else { 792 tend = end; 793 } 794 795 /* 796 * If the caller is smart and only msync()s a range he knows is 797 * dirty, we may be able to avoid an object scan. This results in 798 * a phenominal improvement in performance. We cannot do this 799 * as a matter of course because the object may be huge - e.g. 800 * the size might be in the gigabytes or terrabytes. 801 */ 802 if (msync_flush_flags & MSYNC_FLUSH_HARDSEQ) { 803 vm_pindex_t tscan; 804 int scanlimit; 805 int scanreset; 806 807 scanreset = object->resident_page_count / EASY_SCAN_FACTOR; 808 if (scanreset < 16) 809 scanreset = 16; 810 pagerflags |= VM_PAGER_IGNORE_CLEANCHK; 811 812 scanlimit = scanreset; 813 tscan = tstart; 814 while (tscan < tend) { 815 curgeneration = object->generation; 816 p = vm_page_lookup(object, tscan); 817 if (p == NULL || p->valid == 0) { 818 if (--scanlimit == 0) 819 break; 820 ++tscan; 821 continue; 822 } 823 vm_page_lock(p); 824 vm_page_lock_queues(); 825 vm_page_test_dirty(p); 826 if (p->dirty == 0) { 827 vm_page_unlock_queues(); 828 vm_page_unlock(p); 829 if (--scanlimit == 0) 830 break; 831 ++tscan; 832 continue; 833 } 834 vm_page_unlock_queues(); 835 vm_page_unlock(p); 836 /* 837 * If we have been asked to skip nosync pages and 838 * this is a nosync page, we can't continue. 839 */ 840 if ((flags & OBJPC_NOSYNC) && (p->oflags & VPO_NOSYNC)) { 841 if (--scanlimit == 0) 842 break; 843 ++tscan; 844 continue; 845 } 846 scanlimit = scanreset; 847 848 /* 849 * This returns 0 if it was unable to busy the first 850 * page (i.e. had to sleep). 851 */ 852 tscan += vm_object_page_collect_flush(object, p, curgeneration, pagerflags); 853 854 } 855 856 /* 857 * If everything was dirty and we flushed it successfully, 858 * and the requested range is not the entire object, we 859 * don't have to mess with CLEANCHK or MIGHTBEDIRTY and can 860 * return immediately. 861 */ 862 if (tscan >= tend && (tstart || tend < object->size)) { 863 vm_object_clear_flag(object, OBJ_CLEANING); 864 return; 865 } 866 pagerflags &= ~VM_PAGER_IGNORE_CLEANCHK; 867 } 868 869 /* 870 * Generally set CLEANCHK interlock and make the page read-only so 871 * we can then clear the object flags. 872 * 873 * However, if this is a nosync mmap then the object is likely to 874 * stay dirty so do not mess with the page and do not clear the 875 * object flags. 876 */ 877 clearobjflags = 1; 878 TAILQ_FOREACH(p, &object->memq, listq) { 879 p->oflags |= VPO_CLEANCHK; 880 if ((flags & OBJPC_NOSYNC) && (p->oflags & VPO_NOSYNC)) 881 clearobjflags = 0; 882 else { 883 vm_page_lock(p); 884 vm_page_lock_queues(); 885 pmap_remove_write(p); 886 vm_page_unlock_queues(); 887 vm_page_unlock(p); 888 } 889 } 890 891 if (clearobjflags && (tstart == 0) && (tend == object->size)) 892 vm_object_clear_flag(object, OBJ_MIGHTBEDIRTY); 893 894rescan: 895 curgeneration = object->generation; 896 897 for (p = TAILQ_FIRST(&object->memq); p; p = np) { 898 int n; 899 900 np = TAILQ_NEXT(p, listq); 901 902again: 903 pi = p->pindex; 904 if ((p->oflags & VPO_CLEANCHK) == 0 || 905 (pi < tstart) || (pi >= tend) || 906 p->valid == 0) { 907 p->oflags &= ~VPO_CLEANCHK; 908 continue; 909 } 910 911 vm_page_lock(p); 912 vm_page_lock_queues(); 913 vm_page_test_dirty(p); 914 if (p->dirty == 0) { 915 vm_page_unlock_queues(); 916 vm_page_unlock(p); 917 p->oflags &= ~VPO_CLEANCHK; 918 continue; 919 } 920 vm_page_unlock_queues(); 921 vm_page_unlock(p); 922 /* 923 * If we have been asked to skip nosync pages and this is a 924 * nosync page, skip it. Note that the object flags were 925 * not cleared in this case so we do not have to set them. 926 */ 927 if ((flags & OBJPC_NOSYNC) && (p->oflags & VPO_NOSYNC)) { 928 p->oflags &= ~VPO_CLEANCHK; 929 continue; 930 } 931 932 n = vm_object_page_collect_flush(object, p, 933 curgeneration, pagerflags); 934 if (n == 0) 935 goto rescan; 936 937 if (object->generation != curgeneration) 938 goto rescan; 939 940 /* 941 * Try to optimize the next page. If we can't we pick up 942 * our (random) scan where we left off. 943 */ 944 if (msync_flush_flags & MSYNC_FLUSH_SOFTSEQ) 945 if ((p = vm_page_lookup(object, pi + n)) != NULL) 946 goto again; 947 } 948#if 0 949 VOP_FSYNC(vp, (pagerflags & VM_PAGER_PUT_SYNC)?MNT_WAIT:0, curproc); 950#endif 951 952 vm_object_clear_flag(object, OBJ_CLEANING); 953 return; 954} 955 956static int 957vm_object_page_collect_flush(vm_object_t object, vm_page_t p, int curgeneration, int pagerflags) 958{ 959 int runlen; 960 int maxf; 961 int chkb; 962 int maxb; 963 int i; 964 vm_pindex_t pi; 965 vm_page_t maf[vm_pageout_page_count]; 966 vm_page_t mab[vm_pageout_page_count]; 967 vm_page_t ma[vm_pageout_page_count]; 968 969 mtx_assert(&vm_page_queue_mtx, MA_NOTOWNED); 970 vm_page_lock_assert(p, MA_NOTOWNED); 971 VM_OBJECT_LOCK_ASSERT(object, MA_OWNED); 972 pi = p->pindex; 973 while (vm_page_sleep_if_busy(p, TRUE, "vpcwai")) { 974 if (object->generation != curgeneration) { 975 return(0); 976 } 977 } 978 maxf = 0; 979 for(i = 1; i < vm_pageout_page_count; i++) { 980 vm_page_t tp; 981 982 if ((tp = vm_page_lookup(object, pi + i)) != NULL) { 983 if ((tp->oflags & VPO_BUSY) || 984 ((pagerflags & VM_PAGER_IGNORE_CLEANCHK) == 0 && 985 (tp->oflags & VPO_CLEANCHK) == 0) || 986 (tp->busy != 0)) 987 break; 988 vm_page_lock(tp); 989 vm_page_lock_queues(); 990 vm_page_test_dirty(tp); 991 if (tp->dirty == 0) { 992 vm_page_unlock(tp); 993 vm_page_unlock_queues(); 994 tp->oflags &= ~VPO_CLEANCHK; 995 break; 996 } 997 vm_page_unlock(tp); 998 vm_page_unlock_queues(); 999 maf[ i - 1 ] = tp; 1000 maxf++; 1001 continue; 1002 } 1003 break; 1004 } 1005 1006 maxb = 0; 1007 chkb = vm_pageout_page_count - maxf; 1008 if (chkb) { 1009 for(i = 1; i < chkb;i++) { 1010 vm_page_t tp; 1011 1012 if ((tp = vm_page_lookup(object, pi - i)) != NULL) { 1013 if ((tp->oflags & VPO_BUSY) || 1014 ((pagerflags & VM_PAGER_IGNORE_CLEANCHK) == 0 && 1015 (tp->oflags & VPO_CLEANCHK) == 0) || 1016 (tp->busy != 0)) 1017 break; 1018 vm_page_lock(tp); 1019 vm_page_lock_queues(); 1020 vm_page_test_dirty(tp); 1021 if (tp->dirty == 0) { 1022 vm_page_unlock_queues(); 1023 vm_page_unlock(tp); 1024 tp->oflags &= ~VPO_CLEANCHK; 1025 break; 1026 } 1027 vm_page_unlock_queues(); 1028 vm_page_unlock(tp); 1029 mab[ i - 1 ] = tp; 1030 maxb++; 1031 continue; 1032 } 1033 break; 1034 } 1035 } 1036 1037 for(i = 0; i < maxb; i++) { 1038 int index = (maxb - i) - 1; 1039 ma[index] = mab[i]; 1040 ma[index]->oflags &= ~VPO_CLEANCHK; 1041 } 1042 p->oflags &= ~VPO_CLEANCHK; 1043 ma[maxb] = p; 1044 for(i = 0; i < maxf; i++) { 1045 int index = (maxb + i) + 1; 1046 ma[index] = maf[i]; 1047 ma[index]->oflags &= ~VPO_CLEANCHK; 1048 } 1049 runlen = maxb + maxf + 1; 1050 1051 vm_pageout_flush(ma, runlen, pagerflags); 1052 for (i = 0; i < runlen; i++) { 1053 if (ma[i]->dirty) { 1054 vm_page_lock(ma[i]); 1055 vm_page_lock_queues(); 1056 pmap_remove_write(ma[i]); 1057 vm_page_unlock_queues(); 1058 vm_page_unlock(ma[i]); 1059 ma[i]->oflags |= VPO_CLEANCHK; 1060 1061 /* 1062 * maxf will end up being the actual number of pages 1063 * we wrote out contiguously, non-inclusive of the 1064 * first page. We do not count look-behind pages. 1065 */ 1066 if (i >= maxb + 1 && (maxf > i - maxb - 1)) 1067 maxf = i - maxb - 1; 1068 } 1069 } 1070 return(maxf + 1); 1071} 1072 1073/* 1074 * Note that there is absolutely no sense in writing out 1075 * anonymous objects, so we track down the vnode object 1076 * to write out. 1077 * We invalidate (remove) all pages from the address space 1078 * for semantic correctness. 1079 * 1080 * Note: certain anonymous maps, such as MAP_NOSYNC maps, 1081 * may start out with a NULL object. 1082 */ 1083void 1084vm_object_sync(vm_object_t object, vm_ooffset_t offset, vm_size_t size, 1085 boolean_t syncio, boolean_t invalidate) 1086{ 1087 vm_object_t backing_object; 1088 struct vnode *vp; 1089 struct mount *mp; 1090 int flags; 1091 1092 if (object == NULL) 1093 return; 1094 VM_OBJECT_LOCK(object); 1095 while ((backing_object = object->backing_object) != NULL) { 1096 VM_OBJECT_LOCK(backing_object); 1097 offset += object->backing_object_offset; 1098 VM_OBJECT_UNLOCK(object); 1099 object = backing_object; 1100 if (object->size < OFF_TO_IDX(offset + size)) 1101 size = IDX_TO_OFF(object->size) - offset; 1102 } 1103 /* 1104 * Flush pages if writing is allowed, invalidate them 1105 * if invalidation requested. Pages undergoing I/O 1106 * will be ignored by vm_object_page_remove(). 1107 * 1108 * We cannot lock the vnode and then wait for paging 1109 * to complete without deadlocking against vm_fault. 1110 * Instead we simply call vm_object_page_remove() and 1111 * allow it to block internally on a page-by-page 1112 * basis when it encounters pages undergoing async 1113 * I/O. 1114 */ 1115 if (object->type == OBJT_VNODE && 1116 (object->flags & OBJ_MIGHTBEDIRTY) != 0) { 1117 int vfslocked; 1118 vp = object->handle; 1119 VM_OBJECT_UNLOCK(object); 1120 (void) vn_start_write(vp, &mp, V_WAIT); 1121 vfslocked = VFS_LOCK_GIANT(vp->v_mount); 1122 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY); 1123 flags = (syncio || invalidate) ? OBJPC_SYNC : 0; 1124 flags |= invalidate ? OBJPC_INVAL : 0; 1125 VM_OBJECT_LOCK(object); 1126 vm_object_page_clean(object, 1127 OFF_TO_IDX(offset), 1128 OFF_TO_IDX(offset + size + PAGE_MASK), 1129 flags); 1130 VM_OBJECT_UNLOCK(object); 1131 VOP_UNLOCK(vp, 0); 1132 VFS_UNLOCK_GIANT(vfslocked); 1133 vn_finished_write(mp); 1134 VM_OBJECT_LOCK(object); 1135 } 1136 if ((object->type == OBJT_VNODE || 1137 object->type == OBJT_DEVICE) && invalidate) { 1138 boolean_t purge; 1139 purge = old_msync || (object->type == OBJT_DEVICE); 1140 vm_object_page_remove(object, 1141 OFF_TO_IDX(offset), 1142 OFF_TO_IDX(offset + size + PAGE_MASK), 1143 purge ? FALSE : TRUE); 1144 } 1145 VM_OBJECT_UNLOCK(object); 1146} 1147 1148/* 1149 * vm_object_madvise: 1150 * 1151 * Implements the madvise function at the object/page level. 1152 * 1153 * MADV_WILLNEED (any object) 1154 * 1155 * Activate the specified pages if they are resident. 1156 * 1157 * MADV_DONTNEED (any object) 1158 * 1159 * Deactivate the specified pages if they are resident. 1160 * 1161 * MADV_FREE (OBJT_DEFAULT/OBJT_SWAP objects, 1162 * OBJ_ONEMAPPING only) 1163 * 1164 * Deactivate and clean the specified pages if they are 1165 * resident. This permits the process to reuse the pages 1166 * without faulting or the kernel to reclaim the pages 1167 * without I/O. 1168 */ 1169void 1170vm_object_madvise(vm_object_t object, vm_pindex_t pindex, int count, int advise) 1171{ 1172 vm_pindex_t end, tpindex; 1173 vm_object_t backing_object, tobject; 1174 vm_page_t m; 1175 1176 if (object == NULL) 1177 return; 1178 VM_OBJECT_LOCK(object); 1179 end = pindex + count; 1180 /* 1181 * Locate and adjust resident pages 1182 */ 1183 for (; pindex < end; pindex += 1) { 1184relookup: 1185 tobject = object; 1186 tpindex = pindex; 1187shadowlookup: 1188 /* 1189 * MADV_FREE only operates on OBJT_DEFAULT or OBJT_SWAP pages 1190 * and those pages must be OBJ_ONEMAPPING. 1191 */ 1192 if (advise == MADV_FREE) { 1193 if ((tobject->type != OBJT_DEFAULT && 1194 tobject->type != OBJT_SWAP) || 1195 (tobject->flags & OBJ_ONEMAPPING) == 0) { 1196 goto unlock_tobject; 1197 } 1198 } else if (tobject->type == OBJT_PHYS) 1199 goto unlock_tobject; 1200 m = vm_page_lookup(tobject, tpindex); 1201 if (m == NULL && advise == MADV_WILLNEED) { 1202 /* 1203 * If the page is cached, reactivate it. 1204 */ 1205 m = vm_page_alloc(tobject, tpindex, VM_ALLOC_IFCACHED | 1206 VM_ALLOC_NOBUSY); 1207 } 1208 if (m == NULL) { 1209 /* 1210 * There may be swap even if there is no backing page 1211 */ 1212 if (advise == MADV_FREE && tobject->type == OBJT_SWAP) 1213 swap_pager_freespace(tobject, tpindex, 1); 1214 /* 1215 * next object 1216 */ 1217 backing_object = tobject->backing_object; 1218 if (backing_object == NULL) 1219 goto unlock_tobject; 1220 VM_OBJECT_LOCK(backing_object); 1221 tpindex += OFF_TO_IDX(tobject->backing_object_offset); 1222 if (tobject != object) 1223 VM_OBJECT_UNLOCK(tobject); 1224 tobject = backing_object; 1225 goto shadowlookup; 1226 } else if (m->valid != VM_PAGE_BITS_ALL) 1227 goto unlock_tobject; 1228 /* 1229 * If the page is not in a normal state, skip it. 1230 */ 1231 vm_page_lock(m); 1232 vm_page_lock_queues(); 1233 if (m->hold_count != 0 || m->wire_count != 0) { 1234 vm_page_unlock_queues(); 1235 vm_page_unlock(m); 1236 goto unlock_tobject; 1237 } 1238 if ((m->oflags & VPO_BUSY) || m->busy) { 1239 if (advise == MADV_WILLNEED) 1240 /* 1241 * Reference the page before unlocking and 1242 * sleeping so that the page daemon is less 1243 * likely to reclaim it. 1244 */ 1245 vm_page_flag_set(m, PG_REFERENCED); 1246 vm_page_unlock_queues(); 1247 vm_page_unlock(m); 1248 if (object != tobject) 1249 VM_OBJECT_UNLOCK(object); 1250 m->oflags |= VPO_WANTED; 1251 msleep(m, VM_OBJECT_MTX(tobject), PDROP | PVM, "madvpo", 1252 0); 1253 VM_OBJECT_LOCK(object); 1254 goto relookup; 1255 } 1256 if (advise == MADV_WILLNEED) { 1257 vm_page_activate(m); 1258 } else if (advise == MADV_DONTNEED) { 1259 vm_page_dontneed(m); 1260 } else if (advise == MADV_FREE) { 1261 /* 1262 * Mark the page clean. This will allow the page 1263 * to be freed up by the system. However, such pages 1264 * are often reused quickly by malloc()/free() 1265 * so we do not do anything that would cause 1266 * a page fault if we can help it. 1267 * 1268 * Specifically, we do not try to actually free 1269 * the page now nor do we try to put it in the 1270 * cache (which would cause a page fault on reuse). 1271 * 1272 * But we do make the page is freeable as we 1273 * can without actually taking the step of unmapping 1274 * it. 1275 */ 1276 pmap_clear_modify(m); 1277 m->dirty = 0; 1278 m->act_count = 0; 1279 vm_page_dontneed(m); 1280 } 1281 vm_page_unlock_queues(); 1282 vm_page_unlock(m); 1283 if (advise == MADV_FREE && tobject->type == OBJT_SWAP) 1284 swap_pager_freespace(tobject, tpindex, 1); 1285unlock_tobject: 1286 if (tobject != object) 1287 VM_OBJECT_UNLOCK(tobject); 1288 } 1289 VM_OBJECT_UNLOCK(object); 1290} 1291 1292/* 1293 * vm_object_shadow: 1294 * 1295 * Create a new object which is backed by the 1296 * specified existing object range. The source 1297 * object reference is deallocated. 1298 * 1299 * The new object and offset into that object 1300 * are returned in the source parameters. 1301 */ 1302void 1303vm_object_shadow( 1304 vm_object_t *object, /* IN/OUT */ 1305 vm_ooffset_t *offset, /* IN/OUT */ 1306 vm_size_t length) 1307{ 1308 vm_object_t source; 1309 vm_object_t result; 1310 1311 source = *object; 1312 1313 /* 1314 * Don't create the new object if the old object isn't shared. 1315 */ 1316 if (source != NULL) { 1317 VM_OBJECT_LOCK(source); 1318 if (source->ref_count == 1 && 1319 source->handle == NULL && 1320 (source->type == OBJT_DEFAULT || 1321 source->type == OBJT_SWAP)) { 1322 VM_OBJECT_UNLOCK(source); 1323 return; 1324 } 1325 VM_OBJECT_UNLOCK(source); 1326 } 1327 1328 /* 1329 * Allocate a new object with the given length. 1330 */ 1331 result = vm_object_allocate(OBJT_DEFAULT, length); 1332 1333 /* 1334 * The new object shadows the source object, adding a reference to it. 1335 * Our caller changes his reference to point to the new object, 1336 * removing a reference to the source object. Net result: no change 1337 * of reference count. 1338 * 1339 * Try to optimize the result object's page color when shadowing 1340 * in order to maintain page coloring consistency in the combined 1341 * shadowed object. 1342 */ 1343 result->backing_object = source; 1344 /* 1345 * Store the offset into the source object, and fix up the offset into 1346 * the new object. 1347 */ 1348 result->backing_object_offset = *offset; 1349 if (source != NULL) { 1350 VM_OBJECT_LOCK(source); 1351 LIST_INSERT_HEAD(&source->shadow_head, result, shadow_list); 1352 source->shadow_count++; 1353 source->generation++; 1354#if VM_NRESERVLEVEL > 0 1355 result->flags |= source->flags & OBJ_COLORED; 1356 result->pg_color = (source->pg_color + OFF_TO_IDX(*offset)) & 1357 ((1 << (VM_NFREEORDER - 1)) - 1); 1358#endif 1359 VM_OBJECT_UNLOCK(source); 1360 } 1361 1362 1363 /* 1364 * Return the new things 1365 */ 1366 *offset = 0; 1367 *object = result; 1368} 1369 1370/* 1371 * vm_object_split: 1372 * 1373 * Split the pages in a map entry into a new object. This affords 1374 * easier removal of unused pages, and keeps object inheritance from 1375 * being a negative impact on memory usage. 1376 */ 1377void 1378vm_object_split(vm_map_entry_t entry) 1379{ 1380 vm_page_t m, m_next; 1381 vm_object_t orig_object, new_object, source; 1382 vm_pindex_t idx, offidxstart; 1383 vm_size_t size; 1384 1385 orig_object = entry->object.vm_object; 1386 if (orig_object->type != OBJT_DEFAULT && orig_object->type != OBJT_SWAP) 1387 return; 1388 if (orig_object->ref_count <= 1) 1389 return; 1390 VM_OBJECT_UNLOCK(orig_object); 1391 1392 offidxstart = OFF_TO_IDX(entry->offset); 1393 size = atop(entry->end - entry->start); 1394 1395 /* 1396 * If swap_pager_copy() is later called, it will convert new_object 1397 * into a swap object. 1398 */ 1399 new_object = vm_object_allocate(OBJT_DEFAULT, size); 1400 1401 /* 1402 * At this point, the new object is still private, so the order in 1403 * which the original and new objects are locked does not matter. 1404 */ 1405 VM_OBJECT_LOCK(new_object); 1406 VM_OBJECT_LOCK(orig_object); 1407 source = orig_object->backing_object; 1408 if (source != NULL) { 1409 VM_OBJECT_LOCK(source); 1410 if ((source->flags & OBJ_DEAD) != 0) { 1411 VM_OBJECT_UNLOCK(source); 1412 VM_OBJECT_UNLOCK(orig_object); 1413 VM_OBJECT_UNLOCK(new_object); 1414 vm_object_deallocate(new_object); 1415 VM_OBJECT_LOCK(orig_object); 1416 return; 1417 } 1418 LIST_INSERT_HEAD(&source->shadow_head, 1419 new_object, shadow_list); 1420 source->shadow_count++; 1421 source->generation++; 1422 vm_object_reference_locked(source); /* for new_object */ 1423 vm_object_clear_flag(source, OBJ_ONEMAPPING); 1424 VM_OBJECT_UNLOCK(source); 1425 new_object->backing_object_offset = 1426 orig_object->backing_object_offset + entry->offset; 1427 new_object->backing_object = source; 1428 } 1429 if (orig_object->uip != NULL) { 1430 new_object->uip = orig_object->uip; 1431 uihold(orig_object->uip); 1432 new_object->charge = ptoa(size); 1433 KASSERT(orig_object->charge >= ptoa(size), 1434 ("orig_object->charge < 0")); 1435 orig_object->charge -= ptoa(size); 1436 } 1437retry: 1438 if ((m = TAILQ_FIRST(&orig_object->memq)) != NULL) { 1439 if (m->pindex < offidxstart) { 1440 m = vm_page_splay(offidxstart, orig_object->root); 1441 if ((orig_object->root = m)->pindex < offidxstart) 1442 m = TAILQ_NEXT(m, listq); 1443 } 1444 } 1445 for (; m != NULL && (idx = m->pindex - offidxstart) < size; 1446 m = m_next) { 1447 m_next = TAILQ_NEXT(m, listq); 1448 1449 /* 1450 * We must wait for pending I/O to complete before we can 1451 * rename the page. 1452 * 1453 * We do not have to VM_PROT_NONE the page as mappings should 1454 * not be changed by this operation. 1455 */ 1456 if ((m->oflags & VPO_BUSY) || m->busy) { 1457 vm_page_unlock_queues(); 1458 VM_OBJECT_UNLOCK(new_object); 1459 m->oflags |= VPO_WANTED; 1460 msleep(m, VM_OBJECT_MTX(orig_object), PVM, "spltwt", 0); 1461 VM_OBJECT_LOCK(new_object); 1462 goto retry; 1463 } 1464 vm_page_lock(m); 1465 vm_page_lock_queues(); 1466 vm_page_rename(m, new_object, idx); 1467 vm_page_unlock_queues(); 1468 vm_page_unlock(m); 1469 /* page automatically made dirty by rename and cache handled */ 1470 vm_page_busy(m); 1471 } 1472 if (orig_object->type == OBJT_SWAP) { 1473 /* 1474 * swap_pager_copy() can sleep, in which case the orig_object's 1475 * and new_object's locks are released and reacquired. 1476 */ 1477 swap_pager_copy(orig_object, new_object, offidxstart, 0); 1478 1479 /* 1480 * Transfer any cached pages from orig_object to new_object. 1481 */ 1482 if (__predict_false(orig_object->cache != NULL)) 1483 vm_page_cache_transfer(orig_object, offidxstart, 1484 new_object); 1485 } 1486 VM_OBJECT_UNLOCK(orig_object); 1487 TAILQ_FOREACH(m, &new_object->memq, listq) 1488 vm_page_wakeup(m); 1489 VM_OBJECT_UNLOCK(new_object); 1490 entry->object.vm_object = new_object; 1491 entry->offset = 0LL; 1492 vm_object_deallocate(orig_object); 1493 VM_OBJECT_LOCK(new_object); 1494} 1495 1496#define OBSC_TEST_ALL_SHADOWED 0x0001 1497#define OBSC_COLLAPSE_NOWAIT 0x0002 1498#define OBSC_COLLAPSE_WAIT 0x0004 1499 1500static int 1501vm_object_backing_scan(vm_object_t object, int op) 1502{ 1503 int r = 1; 1504 vm_page_t p; 1505 vm_object_t backing_object; 1506 vm_pindex_t backing_offset_index; 1507 1508 VM_OBJECT_LOCK_ASSERT(object, MA_OWNED); 1509 VM_OBJECT_LOCK_ASSERT(object->backing_object, MA_OWNED); 1510 1511 backing_object = object->backing_object; 1512 backing_offset_index = OFF_TO_IDX(object->backing_object_offset); 1513 1514 /* 1515 * Initial conditions 1516 */ 1517 if (op & OBSC_TEST_ALL_SHADOWED) { 1518 /* 1519 * We do not want to have to test for the existence of cache 1520 * or swap pages in the backing object. XXX but with the 1521 * new swapper this would be pretty easy to do. 1522 * 1523 * XXX what about anonymous MAP_SHARED memory that hasn't 1524 * been ZFOD faulted yet? If we do not test for this, the 1525 * shadow test may succeed! XXX 1526 */ 1527 if (backing_object->type != OBJT_DEFAULT) { 1528 return (0); 1529 } 1530 } 1531 if (op & OBSC_COLLAPSE_WAIT) { 1532 vm_object_set_flag(backing_object, OBJ_DEAD); 1533 } 1534 1535 /* 1536 * Our scan 1537 */ 1538 p = TAILQ_FIRST(&backing_object->memq); 1539 while (p) { 1540 vm_page_t next = TAILQ_NEXT(p, listq); 1541 vm_pindex_t new_pindex = p->pindex - backing_offset_index; 1542 1543 if (op & OBSC_TEST_ALL_SHADOWED) { 1544 vm_page_t pp; 1545 1546 /* 1547 * Ignore pages outside the parent object's range 1548 * and outside the parent object's mapping of the 1549 * backing object. 1550 * 1551 * note that we do not busy the backing object's 1552 * page. 1553 */ 1554 if ( 1555 p->pindex < backing_offset_index || 1556 new_pindex >= object->size 1557 ) { 1558 p = next; 1559 continue; 1560 } 1561 1562 /* 1563 * See if the parent has the page or if the parent's 1564 * object pager has the page. If the parent has the 1565 * page but the page is not valid, the parent's 1566 * object pager must have the page. 1567 * 1568 * If this fails, the parent does not completely shadow 1569 * the object and we might as well give up now. 1570 */ 1571 1572 pp = vm_page_lookup(object, new_pindex); 1573 if ( 1574 (pp == NULL || pp->valid == 0) && 1575 !vm_pager_has_page(object, new_pindex, NULL, NULL) 1576 ) { 1577 r = 0; 1578 break; 1579 } 1580 } 1581 1582 /* 1583 * Check for busy page 1584 */ 1585 if (op & (OBSC_COLLAPSE_WAIT | OBSC_COLLAPSE_NOWAIT)) { 1586 vm_page_t pp; 1587 1588 if (op & OBSC_COLLAPSE_NOWAIT) { 1589 if ((p->oflags & VPO_BUSY) || 1590 !p->valid || 1591 p->busy) { 1592 p = next; 1593 continue; 1594 } 1595 } else if (op & OBSC_COLLAPSE_WAIT) { 1596 if ((p->oflags & VPO_BUSY) || p->busy) { 1597 VM_OBJECT_UNLOCK(object); 1598 p->oflags |= VPO_WANTED; 1599 msleep(p, VM_OBJECT_MTX(backing_object), 1600 PDROP | PVM, "vmocol", 0); 1601 VM_OBJECT_LOCK(object); 1602 VM_OBJECT_LOCK(backing_object); 1603 /* 1604 * If we slept, anything could have 1605 * happened. Since the object is 1606 * marked dead, the backing offset 1607 * should not have changed so we 1608 * just restart our scan. 1609 */ 1610 p = TAILQ_FIRST(&backing_object->memq); 1611 continue; 1612 } 1613 } 1614 1615 KASSERT( 1616 p->object == backing_object, 1617 ("vm_object_backing_scan: object mismatch") 1618 ); 1619 1620 /* 1621 * Destroy any associated swap 1622 */ 1623 if (backing_object->type == OBJT_SWAP) { 1624 swap_pager_freespace( 1625 backing_object, 1626 p->pindex, 1627 1 1628 ); 1629 } 1630 1631 if ( 1632 p->pindex < backing_offset_index || 1633 new_pindex >= object->size 1634 ) { 1635 /* 1636 * Page is out of the parent object's range, we 1637 * can simply destroy it. 1638 */ 1639 vm_page_lock(p); 1640 vm_page_lock_queues(); 1641 KASSERT(!pmap_page_is_mapped(p), 1642 ("freeing mapped page %p", p)); 1643 if (p->wire_count == 0) 1644 vm_page_free(p); 1645 else 1646 vm_page_remove(p); 1647 vm_page_unlock_queues(); 1648 vm_page_unlock(p); 1649 p = next; 1650 continue; 1651 } 1652 1653 pp = vm_page_lookup(object, new_pindex); 1654 if ( 1655 pp != NULL || 1656 vm_pager_has_page(object, new_pindex, NULL, NULL) 1657 ) { 1658 /* 1659 * page already exists in parent OR swap exists 1660 * for this location in the parent. Destroy 1661 * the original page from the backing object. 1662 * 1663 * Leave the parent's page alone 1664 */ 1665 vm_page_lock(p); 1666 vm_page_lock_queues(); 1667 KASSERT(!pmap_page_is_mapped(p), 1668 ("freeing mapped page %p", p)); 1669 if (p->wire_count == 0) 1670 vm_page_free(p); 1671 else 1672 vm_page_remove(p); 1673 vm_page_unlock_queues(); 1674 vm_page_unlock(p); 1675 p = next; 1676 continue; 1677 } 1678 1679#if VM_NRESERVLEVEL > 0 1680 /* 1681 * Rename the reservation. 1682 */ 1683 vm_reserv_rename(p, object, backing_object, 1684 backing_offset_index); 1685#endif 1686 1687 /* 1688 * Page does not exist in parent, rename the 1689 * page from the backing object to the main object. 1690 * 1691 * If the page was mapped to a process, it can remain 1692 * mapped through the rename. 1693 */ 1694 vm_page_lock(p); 1695 vm_page_lock_queues(); 1696 vm_page_rename(p, object, new_pindex); 1697 vm_page_unlock_queues(); 1698 vm_page_unlock(p); 1699 /* page automatically made dirty by rename */ 1700 } 1701 p = next; 1702 } 1703 return (r); 1704} 1705 1706 1707/* 1708 * this version of collapse allows the operation to occur earlier and 1709 * when paging_in_progress is true for an object... This is not a complete 1710 * operation, but should plug 99.9% of the rest of the leaks. 1711 */ 1712static void 1713vm_object_qcollapse(vm_object_t object) 1714{ 1715 vm_object_t backing_object = object->backing_object; 1716 1717 VM_OBJECT_LOCK_ASSERT(object, MA_OWNED); 1718 VM_OBJECT_LOCK_ASSERT(backing_object, MA_OWNED); 1719 1720 if (backing_object->ref_count != 1) 1721 return; 1722 1723 vm_object_backing_scan(object, OBSC_COLLAPSE_NOWAIT); 1724} 1725 1726/* 1727 * vm_object_collapse: 1728 * 1729 * Collapse an object with the object backing it. 1730 * Pages in the backing object are moved into the 1731 * parent, and the backing object is deallocated. 1732 */ 1733void 1734vm_object_collapse(vm_object_t object) 1735{ 1736 VM_OBJECT_LOCK_ASSERT(object, MA_OWNED); 1737 1738 while (TRUE) { 1739 vm_object_t backing_object; 1740 1741 /* 1742 * Verify that the conditions are right for collapse: 1743 * 1744 * The object exists and the backing object exists. 1745 */ 1746 if ((backing_object = object->backing_object) == NULL) 1747 break; 1748 1749 /* 1750 * we check the backing object first, because it is most likely 1751 * not collapsable. 1752 */ 1753 VM_OBJECT_LOCK(backing_object); 1754 if (backing_object->handle != NULL || 1755 (backing_object->type != OBJT_DEFAULT && 1756 backing_object->type != OBJT_SWAP) || 1757 (backing_object->flags & OBJ_DEAD) || 1758 object->handle != NULL || 1759 (object->type != OBJT_DEFAULT && 1760 object->type != OBJT_SWAP) || 1761 (object->flags & OBJ_DEAD)) { 1762 VM_OBJECT_UNLOCK(backing_object); 1763 break; 1764 } 1765 1766 if ( 1767 object->paging_in_progress != 0 || 1768 backing_object->paging_in_progress != 0 1769 ) { 1770 vm_object_qcollapse(object); 1771 VM_OBJECT_UNLOCK(backing_object); 1772 break; 1773 } 1774 /* 1775 * We know that we can either collapse the backing object (if 1776 * the parent is the only reference to it) or (perhaps) have 1777 * the parent bypass the object if the parent happens to shadow 1778 * all the resident pages in the entire backing object. 1779 * 1780 * This is ignoring pager-backed pages such as swap pages. 1781 * vm_object_backing_scan fails the shadowing test in this 1782 * case. 1783 */ 1784 if (backing_object->ref_count == 1) { 1785 /* 1786 * If there is exactly one reference to the backing 1787 * object, we can collapse it into the parent. 1788 */ 1789 vm_object_backing_scan(object, OBSC_COLLAPSE_WAIT); 1790 1791#if VM_NRESERVLEVEL > 0 1792 /* 1793 * Break any reservations from backing_object. 1794 */ 1795 if (__predict_false(!LIST_EMPTY(&backing_object->rvq))) 1796 vm_reserv_break_all(backing_object); 1797#endif 1798 1799 /* 1800 * Move the pager from backing_object to object. 1801 */ 1802 if (backing_object->type == OBJT_SWAP) { 1803 /* 1804 * swap_pager_copy() can sleep, in which case 1805 * the backing_object's and object's locks are 1806 * released and reacquired. 1807 */ 1808 swap_pager_copy( 1809 backing_object, 1810 object, 1811 OFF_TO_IDX(object->backing_object_offset), TRUE); 1812 1813 /* 1814 * Free any cached pages from backing_object. 1815 */ 1816 if (__predict_false(backing_object->cache != NULL)) 1817 vm_page_cache_free(backing_object, 0, 0); 1818 } 1819 /* 1820 * Object now shadows whatever backing_object did. 1821 * Note that the reference to 1822 * backing_object->backing_object moves from within 1823 * backing_object to within object. 1824 */ 1825 LIST_REMOVE(object, shadow_list); 1826 backing_object->shadow_count--; 1827 backing_object->generation++; 1828 if (backing_object->backing_object) { 1829 VM_OBJECT_LOCK(backing_object->backing_object); 1830 LIST_REMOVE(backing_object, shadow_list); 1831 LIST_INSERT_HEAD( 1832 &backing_object->backing_object->shadow_head, 1833 object, shadow_list); 1834 /* 1835 * The shadow_count has not changed. 1836 */ 1837 backing_object->backing_object->generation++; 1838 VM_OBJECT_UNLOCK(backing_object->backing_object); 1839 } 1840 object->backing_object = backing_object->backing_object; 1841 object->backing_object_offset += 1842 backing_object->backing_object_offset; 1843 1844 /* 1845 * Discard backing_object. 1846 * 1847 * Since the backing object has no pages, no pager left, 1848 * and no object references within it, all that is 1849 * necessary is to dispose of it. 1850 */ 1851 KASSERT(backing_object->ref_count == 1, ( 1852"backing_object %p was somehow re-referenced during collapse!", 1853 backing_object)); 1854 VM_OBJECT_UNLOCK(backing_object); 1855 vm_object_destroy(backing_object); 1856 1857 object_collapses++; 1858 } else { 1859 vm_object_t new_backing_object; 1860 1861 /* 1862 * If we do not entirely shadow the backing object, 1863 * there is nothing we can do so we give up. 1864 */ 1865 if (object->resident_page_count != object->size && 1866 vm_object_backing_scan(object, 1867 OBSC_TEST_ALL_SHADOWED) == 0) { 1868 VM_OBJECT_UNLOCK(backing_object); 1869 break; 1870 } 1871 1872 /* 1873 * Make the parent shadow the next object in the 1874 * chain. Deallocating backing_object will not remove 1875 * it, since its reference count is at least 2. 1876 */ 1877 LIST_REMOVE(object, shadow_list); 1878 backing_object->shadow_count--; 1879 backing_object->generation++; 1880 1881 new_backing_object = backing_object->backing_object; 1882 if ((object->backing_object = new_backing_object) != NULL) { 1883 VM_OBJECT_LOCK(new_backing_object); 1884 LIST_INSERT_HEAD( 1885 &new_backing_object->shadow_head, 1886 object, 1887 shadow_list 1888 ); 1889 new_backing_object->shadow_count++; 1890 new_backing_object->generation++; 1891 vm_object_reference_locked(new_backing_object); 1892 VM_OBJECT_UNLOCK(new_backing_object); 1893 object->backing_object_offset += 1894 backing_object->backing_object_offset; 1895 } 1896 1897 /* 1898 * Drop the reference count on backing_object. Since 1899 * its ref_count was at least 2, it will not vanish. 1900 */ 1901 backing_object->ref_count--; 1902 VM_OBJECT_UNLOCK(backing_object); 1903 object_bypasses++; 1904 } 1905 1906 /* 1907 * Try again with this object's new backing object. 1908 */ 1909 } 1910} 1911 1912/* 1913 * vm_object_page_remove: 1914 * 1915 * For the given object, either frees or invalidates each of the 1916 * specified pages. In general, a page is freed. However, if a 1917 * page is wired for any reason other than the existence of a 1918 * managed, wired mapping, then it may be invalidated but not 1919 * removed from the object. Pages are specified by the given 1920 * range ["start", "end") and Boolean "clean_only". As a 1921 * special case, if "end" is zero, then the range extends from 1922 * "start" to the end of the object. If "clean_only" is TRUE, 1923 * then only the non-dirty pages within the specified range are 1924 * affected. 1925 * 1926 * In general, this operation should only be performed on objects 1927 * that contain managed pages. There are two exceptions. First, 1928 * it may be performed on the kernel and kmem objects. Second, 1929 * it may be used by msync(..., MS_INVALIDATE) to invalidate 1930 * device-backed pages. 1931 * 1932 * The object must be locked. 1933 */ 1934void 1935vm_object_page_remove(vm_object_t object, vm_pindex_t start, vm_pindex_t end, 1936 boolean_t clean_only) 1937{ 1938 vm_page_t p, next; 1939 int wirings; 1940 1941 VM_OBJECT_LOCK_ASSERT(object, MA_OWNED); 1942 if (object->resident_page_count == 0) 1943 goto skipmemq; 1944 1945 /* 1946 * Since physically-backed objects do not use managed pages, we can't 1947 * remove pages from the object (we must instead remove the page 1948 * references, and then destroy the object). 1949 */ 1950 KASSERT(object->type != OBJT_PHYS || object == kernel_object || 1951 object == kmem_object, 1952 ("attempt to remove pages from a physical object")); 1953 1954 vm_object_pip_add(object, 1); 1955again: 1956 if ((p = TAILQ_FIRST(&object->memq)) != NULL) { 1957 if (p->pindex < start) { 1958 p = vm_page_splay(start, object->root); 1959 if ((object->root = p)->pindex < start) 1960 p = TAILQ_NEXT(p, listq); 1961 } 1962 } 1963 1964 /* 1965 * Assert: the variable p is either (1) the page with the 1966 * least pindex greater than or equal to the parameter pindex 1967 * or (2) NULL. 1968 */ 1969 for (; 1970 p != NULL && (p->pindex < end || end == 0); 1971 p = next) { 1972 next = TAILQ_NEXT(p, listq); 1973 1974 /* 1975 * If the page is wired for any reason besides the 1976 * existence of managed, wired mappings, then it cannot 1977 * be freed. For example, fictitious pages, which 1978 * represent device memory, are inherently wired and 1979 * cannot be freed. They can, however, be invalidated 1980 * if "clean_only" is FALSE. 1981 */ 1982 vm_page_lock(p); 1983 vm_page_lock_queues(); 1984 if ((wirings = p->wire_count) != 0 && 1985 (wirings = pmap_page_wired_mappings(p)) != p->wire_count) { 1986 /* Fictitious pages do not have managed mappings. */ 1987 if ((p->flags & PG_FICTITIOUS) == 0) 1988 pmap_remove_all(p); 1989 /* Account for removal of managed, wired mappings. */ 1990 p->wire_count -= wirings; 1991 if (!clean_only) { 1992 p->valid = 0; 1993 vm_page_undirty(p); 1994 } 1995 vm_page_unlock_queues(); 1996 vm_page_unlock(p); 1997 continue; 1998 } 1999 if (vm_page_sleep_if_busy(p, TRUE, "vmopar")) 2000 goto again; 2001 KASSERT((p->flags & PG_FICTITIOUS) == 0, 2002 ("vm_object_page_remove: page %p is fictitious", p)); 2003 if (clean_only && p->valid) { 2004 pmap_remove_write(p); 2005 if (p->dirty) { 2006 vm_page_unlock_queues(); 2007 vm_page_unlock(p); 2008 continue; 2009 } 2010 } 2011 pmap_remove_all(p); 2012 /* Account for removal of managed, wired mappings. */ 2013 if (wirings != 0) 2014 p->wire_count -= wirings; 2015 vm_page_free(p); 2016 vm_page_unlock_queues(); 2017 vm_page_unlock(p); 2018 } 2019 vm_object_pip_wakeup(object); 2020skipmemq: 2021 if (__predict_false(object->cache != NULL)) 2022 vm_page_cache_free(object, start, end); 2023} 2024 2025/* 2026 * Populate the specified range of the object with valid pages. Returns 2027 * TRUE if the range is successfully populated and FALSE otherwise. 2028 * 2029 * Note: This function should be optimized to pass a larger array of 2030 * pages to vm_pager_get_pages() before it is applied to a non- 2031 * OBJT_DEVICE object. 2032 * 2033 * The object must be locked. 2034 */ 2035boolean_t 2036vm_object_populate(vm_object_t object, vm_pindex_t start, vm_pindex_t end) 2037{ 2038 vm_page_t m, ma[1]; 2039 vm_pindex_t pindex; 2040 int rv; 2041 2042 VM_OBJECT_LOCK_ASSERT(object, MA_OWNED); 2043 for (pindex = start; pindex < end; pindex++) { 2044 m = vm_page_grab(object, pindex, VM_ALLOC_NORMAL | 2045 VM_ALLOC_RETRY); 2046 if (m->valid != VM_PAGE_BITS_ALL) { 2047 ma[0] = m; 2048 rv = vm_pager_get_pages(object, ma, 1, 0); 2049 m = vm_page_lookup(object, pindex); 2050 if (m == NULL) 2051 break; 2052 if (rv != VM_PAGER_OK) { 2053 vm_page_lock(m); 2054 vm_page_lock_queues(); 2055 vm_page_free(m); 2056 vm_page_unlock_queues(); 2057 vm_page_unlock(m); 2058 break; 2059 } 2060 } 2061 /* 2062 * Keep "m" busy because a subsequent iteration may unlock 2063 * the object. 2064 */ 2065 } 2066 if (pindex > start) { 2067 m = vm_page_lookup(object, start); 2068 while (m != NULL && m->pindex < pindex) { 2069 vm_page_wakeup(m); 2070 m = TAILQ_NEXT(m, listq); 2071 } 2072 } 2073 return (pindex == end); 2074} 2075 2076/* 2077 * Routine: vm_object_coalesce 2078 * Function: Coalesces two objects backing up adjoining 2079 * regions of memory into a single object. 2080 * 2081 * returns TRUE if objects were combined. 2082 * 2083 * NOTE: Only works at the moment if the second object is NULL - 2084 * if it's not, which object do we lock first? 2085 * 2086 * Parameters: 2087 * prev_object First object to coalesce 2088 * prev_offset Offset into prev_object 2089 * prev_size Size of reference to prev_object 2090 * next_size Size of reference to the second object 2091 * reserved Indicator that extension region has 2092 * swap accounted for 2093 * 2094 * Conditions: 2095 * The object must *not* be locked. 2096 */ 2097boolean_t 2098vm_object_coalesce(vm_object_t prev_object, vm_ooffset_t prev_offset, 2099 vm_size_t prev_size, vm_size_t next_size, boolean_t reserved) 2100{ 2101 vm_pindex_t next_pindex; 2102 2103 if (prev_object == NULL) 2104 return (TRUE); 2105 VM_OBJECT_LOCK(prev_object); 2106 if (prev_object->type != OBJT_DEFAULT && 2107 prev_object->type != OBJT_SWAP) { 2108 VM_OBJECT_UNLOCK(prev_object); 2109 return (FALSE); 2110 } 2111 2112 /* 2113 * Try to collapse the object first 2114 */ 2115 vm_object_collapse(prev_object); 2116 2117 /* 2118 * Can't coalesce if: . more than one reference . paged out . shadows 2119 * another object . has a copy elsewhere (any of which mean that the 2120 * pages not mapped to prev_entry may be in use anyway) 2121 */ 2122 if (prev_object->backing_object != NULL) { 2123 VM_OBJECT_UNLOCK(prev_object); 2124 return (FALSE); 2125 } 2126 2127 prev_size >>= PAGE_SHIFT; 2128 next_size >>= PAGE_SHIFT; 2129 next_pindex = OFF_TO_IDX(prev_offset) + prev_size; 2130 2131 if ((prev_object->ref_count > 1) && 2132 (prev_object->size != next_pindex)) { 2133 VM_OBJECT_UNLOCK(prev_object); 2134 return (FALSE); 2135 } 2136 2137 /* 2138 * Account for the charge. 2139 */ 2140 if (prev_object->uip != NULL) { 2141 2142 /* 2143 * If prev_object was charged, then this mapping, 2144 * althought not charged now, may become writable 2145 * later. Non-NULL uip in the object would prevent 2146 * swap reservation during enabling of the write 2147 * access, so reserve swap now. Failed reservation 2148 * cause allocation of the separate object for the map 2149 * entry, and swap reservation for this entry is 2150 * managed in appropriate time. 2151 */ 2152 if (!reserved && !swap_reserve_by_uid(ptoa(next_size), 2153 prev_object->uip)) { 2154 return (FALSE); 2155 } 2156 prev_object->charge += ptoa(next_size); 2157 } 2158 2159 /* 2160 * Remove any pages that may still be in the object from a previous 2161 * deallocation. 2162 */ 2163 if (next_pindex < prev_object->size) { 2164 vm_object_page_remove(prev_object, 2165 next_pindex, 2166 next_pindex + next_size, FALSE); 2167 if (prev_object->type == OBJT_SWAP) 2168 swap_pager_freespace(prev_object, 2169 next_pindex, next_size); 2170#if 0 2171 if (prev_object->uip != NULL) { 2172 KASSERT(prev_object->charge >= 2173 ptoa(prev_object->size - next_pindex), 2174 ("object %p overcharged 1 %jx %jx", prev_object, 2175 (uintmax_t)next_pindex, (uintmax_t)next_size)); 2176 prev_object->charge -= ptoa(prev_object->size - 2177 next_pindex); 2178 } 2179#endif 2180 } 2181 2182 /* 2183 * Extend the object if necessary. 2184 */ 2185 if (next_pindex + next_size > prev_object->size) 2186 prev_object->size = next_pindex + next_size; 2187 2188 VM_OBJECT_UNLOCK(prev_object); 2189 return (TRUE); 2190} 2191 2192void 2193vm_object_set_writeable_dirty(vm_object_t object) 2194{ 2195 2196 VM_OBJECT_LOCK_ASSERT(object, MA_OWNED); 2197 if (object->type != OBJT_VNODE || 2198 (object->flags & OBJ_MIGHTBEDIRTY) != 0) 2199 return; 2200 vm_object_set_flag(object, OBJ_MIGHTBEDIRTY); 2201} 2202 2203#include "opt_ddb.h" 2204#ifdef DDB 2205#include <sys/kernel.h> 2206 2207#include <sys/cons.h> 2208 2209#include <ddb/ddb.h> 2210 2211static int 2212_vm_object_in_map(vm_map_t map, vm_object_t object, vm_map_entry_t entry) 2213{ 2214 vm_map_t tmpm; 2215 vm_map_entry_t tmpe; 2216 vm_object_t obj; 2217 int entcount; 2218 2219 if (map == 0) 2220 return 0; 2221 2222 if (entry == 0) { 2223 tmpe = map->header.next; 2224 entcount = map->nentries; 2225 while (entcount-- && (tmpe != &map->header)) { 2226 if (_vm_object_in_map(map, object, tmpe)) { 2227 return 1; 2228 } 2229 tmpe = tmpe->next; 2230 } 2231 } else if (entry->eflags & MAP_ENTRY_IS_SUB_MAP) { 2232 tmpm = entry->object.sub_map; 2233 tmpe = tmpm->header.next; 2234 entcount = tmpm->nentries; 2235 while (entcount-- && tmpe != &tmpm->header) { 2236 if (_vm_object_in_map(tmpm, object, tmpe)) { 2237 return 1; 2238 } 2239 tmpe = tmpe->next; 2240 } 2241 } else if ((obj = entry->object.vm_object) != NULL) { 2242 for (; obj; obj = obj->backing_object) 2243 if (obj == object) { 2244 return 1; 2245 } 2246 } 2247 return 0; 2248} 2249 2250static int 2251vm_object_in_map(vm_object_t object) 2252{ 2253 struct proc *p; 2254 2255 /* sx_slock(&allproc_lock); */ 2256 FOREACH_PROC_IN_SYSTEM(p) { 2257 if (!p->p_vmspace /* || (p->p_flag & (P_SYSTEM|P_WEXIT)) */) 2258 continue; 2259 if (_vm_object_in_map(&p->p_vmspace->vm_map, object, 0)) { 2260 /* sx_sunlock(&allproc_lock); */ 2261 return 1; 2262 } 2263 } 2264 /* sx_sunlock(&allproc_lock); */ 2265 if (_vm_object_in_map(kernel_map, object, 0)) 2266 return 1; 2267 if (_vm_object_in_map(kmem_map, object, 0)) 2268 return 1; 2269 if (_vm_object_in_map(pager_map, object, 0)) 2270 return 1; 2271 if (_vm_object_in_map(buffer_map, object, 0)) 2272 return 1; 2273 return 0; 2274} 2275 2276DB_SHOW_COMMAND(vmochk, vm_object_check) 2277{ 2278 vm_object_t object; 2279 2280 /* 2281 * make sure that internal objs are in a map somewhere 2282 * and none have zero ref counts. 2283 */ 2284 TAILQ_FOREACH(object, &vm_object_list, object_list) { 2285 if (object->handle == NULL && 2286 (object->type == OBJT_DEFAULT || object->type == OBJT_SWAP)) { 2287 if (object->ref_count == 0) { 2288 db_printf("vmochk: internal obj has zero ref count: %ld\n", 2289 (long)object->size); 2290 } 2291 if (!vm_object_in_map(object)) { 2292 db_printf( 2293 "vmochk: internal obj is not in a map: " 2294 "ref: %d, size: %lu: 0x%lx, backing_object: %p\n", 2295 object->ref_count, (u_long)object->size, 2296 (u_long)object->size, 2297 (void *)object->backing_object); 2298 } 2299 } 2300 } 2301} 2302 2303/* 2304 * vm_object_print: [ debug ] 2305 */ 2306DB_SHOW_COMMAND(object, vm_object_print_static) 2307{ 2308 /* XXX convert args. */ 2309 vm_object_t object = (vm_object_t)addr; 2310 boolean_t full = have_addr; 2311 2312 vm_page_t p; 2313 2314 /* XXX count is an (unused) arg. Avoid shadowing it. */ 2315#define count was_count 2316 2317 int count; 2318 2319 if (object == NULL) 2320 return; 2321 2322 db_iprintf( 2323 "Object %p: type=%d, size=0x%jx, res=%d, ref=%d, flags=0x%x uip %d charge %jx\n", 2324 object, (int)object->type, (uintmax_t)object->size, 2325 object->resident_page_count, object->ref_count, object->flags, 2326 object->uip ? object->uip->ui_uid : -1, (uintmax_t)object->charge); 2327 db_iprintf(" sref=%d, backing_object(%d)=(%p)+0x%jx\n", 2328 object->shadow_count, 2329 object->backing_object ? object->backing_object->ref_count : 0, 2330 object->backing_object, (uintmax_t)object->backing_object_offset); 2331 2332 if (!full) 2333 return; 2334 2335 db_indent += 2; 2336 count = 0; 2337 TAILQ_FOREACH(p, &object->memq, listq) { 2338 if (count == 0) 2339 db_iprintf("memory:="); 2340 else if (count == 6) { 2341 db_printf("\n"); 2342 db_iprintf(" ..."); 2343 count = 0; 2344 } else 2345 db_printf(","); 2346 count++; 2347 2348 db_printf("(off=0x%jx,page=0x%jx)", 2349 (uintmax_t)p->pindex, (uintmax_t)VM_PAGE_TO_PHYS(p)); 2350 } 2351 if (count != 0) 2352 db_printf("\n"); 2353 db_indent -= 2; 2354} 2355 2356/* XXX. */ 2357#undef count 2358 2359/* XXX need this non-static entry for calling from vm_map_print. */ 2360void 2361vm_object_print( 2362 /* db_expr_t */ long addr, 2363 boolean_t have_addr, 2364 /* db_expr_t */ long count, 2365 char *modif) 2366{ 2367 vm_object_print_static(addr, have_addr, count, modif); 2368} 2369 2370DB_SHOW_COMMAND(vmopag, vm_object_print_pages) 2371{ 2372 vm_object_t object; 2373 vm_pindex_t fidx; 2374 vm_paddr_t pa; 2375 vm_page_t m, prev_m; 2376 int rcount, nl, c; 2377 2378 nl = 0; 2379 TAILQ_FOREACH(object, &vm_object_list, object_list) { 2380 db_printf("new object: %p\n", (void *)object); 2381 if (nl > 18) { 2382 c = cngetc(); 2383 if (c != ' ') 2384 return; 2385 nl = 0; 2386 } 2387 nl++; 2388 rcount = 0; 2389 fidx = 0; 2390 pa = -1; 2391 TAILQ_FOREACH(m, &object->memq, listq) { 2392 if (m->pindex > 128) 2393 break; 2394 if ((prev_m = TAILQ_PREV(m, pglist, listq)) != NULL && 2395 prev_m->pindex + 1 != m->pindex) { 2396 if (rcount) { 2397 db_printf(" index(%ld)run(%d)pa(0x%lx)\n", 2398 (long)fidx, rcount, (long)pa); 2399 if (nl > 18) { 2400 c = cngetc(); 2401 if (c != ' ') 2402 return; 2403 nl = 0; 2404 } 2405 nl++; 2406 rcount = 0; 2407 } 2408 } 2409 if (rcount && 2410 (VM_PAGE_TO_PHYS(m) == pa + rcount * PAGE_SIZE)) { 2411 ++rcount; 2412 continue; 2413 } 2414 if (rcount) { 2415 db_printf(" index(%ld)run(%d)pa(0x%lx)\n", 2416 (long)fidx, rcount, (long)pa); 2417 if (nl > 18) { 2418 c = cngetc(); 2419 if (c != ' ') 2420 return; 2421 nl = 0; 2422 } 2423 nl++; 2424 } 2425 fidx = m->pindex; 2426 pa = VM_PAGE_TO_PHYS(m); 2427 rcount = 1; 2428 } 2429 if (rcount) { 2430 db_printf(" index(%ld)run(%d)pa(0x%lx)\n", 2431 (long)fidx, rcount, (long)pa); 2432 if (nl > 18) { 2433 c = cngetc(); 2434 if (c != ' ') 2435 return; 2436 nl = 0; 2437 } 2438 nl++; 2439 } 2440 } 2441} 2442#endif /* DDB */ 2443