vm_object.c revision 270920
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: stable/10/sys/vm/vm_object.c 270920 2014-09-01 07:58:15Z kib $"); 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/rwlock.h> 82#include <sys/vnode.h> 83#include <sys/vmmeter.h> 84#include <sys/sx.h> 85 86#include <vm/vm.h> 87#include <vm/vm_param.h> 88#include <vm/pmap.h> 89#include <vm/vm_map.h> 90#include <vm/vm_object.h> 91#include <vm/vm_page.h> 92#include <vm/vm_pageout.h> 93#include <vm/vm_pager.h> 94#include <vm/swap_pager.h> 95#include <vm/vm_kern.h> 96#include <vm/vm_extern.h> 97#include <vm/vm_radix.h> 98#include <vm/vm_reserv.h> 99#include <vm/uma.h> 100 101static int old_msync; 102SYSCTL_INT(_vm, OID_AUTO, old_msync, CTLFLAG_RW, &old_msync, 0, 103 "Use old (insecure) msync behavior"); 104 105static int vm_object_page_collect_flush(vm_object_t object, vm_page_t p, 106 int pagerflags, int flags, boolean_t *clearobjflags, 107 boolean_t *eio); 108static boolean_t vm_object_page_remove_write(vm_page_t p, int flags, 109 boolean_t *clearobjflags); 110static void vm_object_qcollapse(vm_object_t object); 111static void vm_object_vndeallocate(vm_object_t object); 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 139struct object_q vm_object_list; 140struct mtx vm_object_list_mtx; /* lock for object list and count */ 141 142struct vm_object kernel_object_store; 143struct vm_object kmem_object_store; 144 145static SYSCTL_NODE(_vm_stats, OID_AUTO, object, CTLFLAG_RD, 0, 146 "VM object stats"); 147 148static long object_collapses; 149SYSCTL_LONG(_vm_stats_object, OID_AUTO, collapses, CTLFLAG_RD, 150 &object_collapses, 0, "VM object collapses"); 151 152static long object_bypasses; 153SYSCTL_LONG(_vm_stats_object, OID_AUTO, bypasses, CTLFLAG_RD, 154 &object_bypasses, 0, "VM object bypasses"); 155 156static uma_zone_t obj_zone; 157 158static int vm_object_zinit(void *mem, int size, int flags); 159 160#ifdef INVARIANTS 161static void vm_object_zdtor(void *mem, int size, void *arg); 162 163static void 164vm_object_zdtor(void *mem, int size, void *arg) 165{ 166 vm_object_t object; 167 168 object = (vm_object_t)mem; 169 KASSERT(TAILQ_EMPTY(&object->memq), 170 ("object %p has resident pages in its memq", object)); 171 KASSERT(vm_radix_is_empty(&object->rtree), 172 ("object %p has resident pages in its trie", object)); 173#if VM_NRESERVLEVEL > 0 174 KASSERT(LIST_EMPTY(&object->rvq), 175 ("object %p has reservations", 176 object)); 177#endif 178 KASSERT(vm_object_cache_is_empty(object), 179 ("object %p has cached pages", 180 object)); 181 KASSERT(object->paging_in_progress == 0, 182 ("object %p paging_in_progress = %d", 183 object, object->paging_in_progress)); 184 KASSERT(object->resident_page_count == 0, 185 ("object %p resident_page_count = %d", 186 object, object->resident_page_count)); 187 KASSERT(object->shadow_count == 0, 188 ("object %p shadow_count = %d", 189 object, object->shadow_count)); 190} 191#endif 192 193static int 194vm_object_zinit(void *mem, int size, int flags) 195{ 196 vm_object_t object; 197 198 object = (vm_object_t)mem; 199 bzero(&object->lock, sizeof(object->lock)); 200 rw_init_flags(&object->lock, "vm object", RW_DUPOK); 201 202 /* These are true for any object that has been freed */ 203 object->rtree.rt_root = 0; 204 object->rtree.rt_flags = 0; 205 object->paging_in_progress = 0; 206 object->resident_page_count = 0; 207 object->shadow_count = 0; 208 object->cache.rt_root = 0; 209 object->cache.rt_flags = 0; 210 return (0); 211} 212 213static void 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->type = type; 221 switch (type) { 222 case OBJT_DEAD: 223 panic("_vm_object_allocate: can't create OBJT_DEAD"); 224 case OBJT_DEFAULT: 225 case OBJT_SWAP: 226 object->flags = OBJ_ONEMAPPING; 227 break; 228 case OBJT_DEVICE: 229 case OBJT_SG: 230 object->flags = OBJ_FICTITIOUS | OBJ_UNMANAGED; 231 break; 232 case OBJT_MGTDEVICE: 233 object->flags = OBJ_FICTITIOUS; 234 break; 235 case OBJT_PHYS: 236 object->flags = OBJ_UNMANAGED; 237 break; 238 case OBJT_VNODE: 239 object->flags = 0; 240 break; 241 default: 242 panic("_vm_object_allocate: type %d is undefined", type); 243 } 244 object->size = size; 245 object->generation = 1; 246 object->ref_count = 1; 247 object->memattr = VM_MEMATTR_DEFAULT; 248 object->cred = NULL; 249 object->charge = 0; 250 object->handle = NULL; 251 object->backing_object = NULL; 252 object->backing_object_offset = (vm_ooffset_t) 0; 253#if VM_NRESERVLEVEL > 0 254 LIST_INIT(&object->rvq); 255#endif 256 257 mtx_lock(&vm_object_list_mtx); 258 TAILQ_INSERT_TAIL(&vm_object_list, object, object_list); 259 mtx_unlock(&vm_object_list_mtx); 260} 261 262/* 263 * vm_object_init: 264 * 265 * Initialize the VM objects module. 266 */ 267void 268vm_object_init(void) 269{ 270 TAILQ_INIT(&vm_object_list); 271 mtx_init(&vm_object_list_mtx, "vm object_list", NULL, MTX_DEF); 272 273 rw_init(&kernel_object->lock, "kernel vm object"); 274 _vm_object_allocate(OBJT_PHYS, OFF_TO_IDX(VM_MAX_KERNEL_ADDRESS - VM_MIN_KERNEL_ADDRESS), 275 kernel_object); 276#if VM_NRESERVLEVEL > 0 277 kernel_object->flags |= OBJ_COLORED; 278 kernel_object->pg_color = (u_short)atop(VM_MIN_KERNEL_ADDRESS); 279#endif 280 281 rw_init(&kmem_object->lock, "kmem vm object"); 282 _vm_object_allocate(OBJT_PHYS, OFF_TO_IDX(VM_MAX_KERNEL_ADDRESS - VM_MIN_KERNEL_ADDRESS), 283 kmem_object); 284#if VM_NRESERVLEVEL > 0 285 kmem_object->flags |= OBJ_COLORED; 286 kmem_object->pg_color = (u_short)atop(VM_MIN_KERNEL_ADDRESS); 287#endif 288 289 /* 290 * The lock portion of struct vm_object must be type stable due 291 * to vm_pageout_fallback_object_lock locking a vm object 292 * without holding any references to it. 293 */ 294 obj_zone = uma_zcreate("VM OBJECT", sizeof (struct vm_object), NULL, 295#ifdef INVARIANTS 296 vm_object_zdtor, 297#else 298 NULL, 299#endif 300 vm_object_zinit, NULL, UMA_ALIGN_PTR, UMA_ZONE_NOFREE); 301 302 vm_radix_init(); 303} 304 305void 306vm_object_clear_flag(vm_object_t object, u_short bits) 307{ 308 309 VM_OBJECT_ASSERT_WLOCKED(object); 310 object->flags &= ~bits; 311} 312 313/* 314 * Sets the default memory attribute for the specified object. Pages 315 * that are allocated to this object are by default assigned this memory 316 * attribute. 317 * 318 * Presently, this function must be called before any pages are allocated 319 * to the object. In the future, this requirement may be relaxed for 320 * "default" and "swap" objects. 321 */ 322int 323vm_object_set_memattr(vm_object_t object, vm_memattr_t memattr) 324{ 325 326 VM_OBJECT_ASSERT_WLOCKED(object); 327 switch (object->type) { 328 case OBJT_DEFAULT: 329 case OBJT_DEVICE: 330 case OBJT_MGTDEVICE: 331 case OBJT_PHYS: 332 case OBJT_SG: 333 case OBJT_SWAP: 334 case OBJT_VNODE: 335 if (!TAILQ_EMPTY(&object->memq)) 336 return (KERN_FAILURE); 337 break; 338 case OBJT_DEAD: 339 return (KERN_INVALID_ARGUMENT); 340 default: 341 panic("vm_object_set_memattr: object %p is of undefined type", 342 object); 343 } 344 object->memattr = memattr; 345 return (KERN_SUCCESS); 346} 347 348void 349vm_object_pip_add(vm_object_t object, short i) 350{ 351 352 VM_OBJECT_ASSERT_WLOCKED(object); 353 object->paging_in_progress += i; 354} 355 356void 357vm_object_pip_subtract(vm_object_t object, short i) 358{ 359 360 VM_OBJECT_ASSERT_WLOCKED(object); 361 object->paging_in_progress -= i; 362} 363 364void 365vm_object_pip_wakeup(vm_object_t object) 366{ 367 368 VM_OBJECT_ASSERT_WLOCKED(object); 369 object->paging_in_progress--; 370 if ((object->flags & OBJ_PIPWNT) && object->paging_in_progress == 0) { 371 vm_object_clear_flag(object, OBJ_PIPWNT); 372 wakeup(object); 373 } 374} 375 376void 377vm_object_pip_wakeupn(vm_object_t object, short i) 378{ 379 380 VM_OBJECT_ASSERT_WLOCKED(object); 381 if (i) 382 object->paging_in_progress -= i; 383 if ((object->flags & OBJ_PIPWNT) && object->paging_in_progress == 0) { 384 vm_object_clear_flag(object, OBJ_PIPWNT); 385 wakeup(object); 386 } 387} 388 389void 390vm_object_pip_wait(vm_object_t object, char *waitid) 391{ 392 393 VM_OBJECT_ASSERT_WLOCKED(object); 394 while (object->paging_in_progress) { 395 object->flags |= OBJ_PIPWNT; 396 VM_OBJECT_SLEEP(object, object, PVM, waitid, 0); 397 } 398} 399 400/* 401 * vm_object_allocate: 402 * 403 * Returns a new object with the given size. 404 */ 405vm_object_t 406vm_object_allocate(objtype_t type, vm_pindex_t size) 407{ 408 vm_object_t object; 409 410 object = (vm_object_t)uma_zalloc(obj_zone, M_WAITOK); 411 _vm_object_allocate(type, size, object); 412 return (object); 413} 414 415 416/* 417 * vm_object_reference: 418 * 419 * Gets another reference to the given object. Note: OBJ_DEAD 420 * objects can be referenced during final cleaning. 421 */ 422void 423vm_object_reference(vm_object_t object) 424{ 425 if (object == NULL) 426 return; 427 VM_OBJECT_WLOCK(object); 428 vm_object_reference_locked(object); 429 VM_OBJECT_WUNLOCK(object); 430} 431 432/* 433 * vm_object_reference_locked: 434 * 435 * Gets another reference to the given object. 436 * 437 * The object must be locked. 438 */ 439void 440vm_object_reference_locked(vm_object_t object) 441{ 442 struct vnode *vp; 443 444 VM_OBJECT_ASSERT_WLOCKED(object); 445 object->ref_count++; 446 if (object->type == OBJT_VNODE) { 447 vp = object->handle; 448 vref(vp); 449 } 450} 451 452/* 453 * Handle deallocating an object of type OBJT_VNODE. 454 */ 455static void 456vm_object_vndeallocate(vm_object_t object) 457{ 458 struct vnode *vp = (struct vnode *) object->handle; 459 460 VM_OBJECT_ASSERT_WLOCKED(object); 461 KASSERT(object->type == OBJT_VNODE, 462 ("vm_object_vndeallocate: not a vnode object")); 463 KASSERT(vp != NULL, ("vm_object_vndeallocate: missing vp")); 464#ifdef INVARIANTS 465 if (object->ref_count == 0) { 466 vprint("vm_object_vndeallocate", vp); 467 panic("vm_object_vndeallocate: bad object reference count"); 468 } 469#endif 470 471 if (object->ref_count > 1) { 472 object->ref_count--; 473 VM_OBJECT_WUNLOCK(object); 474 /* vrele may need the vnode lock. */ 475 vrele(vp); 476 } else { 477 vhold(vp); 478 VM_OBJECT_WUNLOCK(object); 479 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY); 480 vdrop(vp); 481 VM_OBJECT_WLOCK(object); 482 object->ref_count--; 483 if (object->type == OBJT_DEAD) { 484 VM_OBJECT_WUNLOCK(object); 485 VOP_UNLOCK(vp, 0); 486 } else { 487 if (object->ref_count == 0) 488 VOP_UNSET_TEXT(vp); 489 VM_OBJECT_WUNLOCK(object); 490 vput(vp); 491 } 492 } 493} 494 495/* 496 * vm_object_deallocate: 497 * 498 * Release a reference to the specified object, 499 * gained either through a vm_object_allocate 500 * or a vm_object_reference call. When all references 501 * are gone, storage associated with this object 502 * may be relinquished. 503 * 504 * No object may be locked. 505 */ 506void 507vm_object_deallocate(vm_object_t object) 508{ 509 vm_object_t temp; 510 struct vnode *vp; 511 512 while (object != NULL) { 513 VM_OBJECT_WLOCK(object); 514 if (object->type == OBJT_VNODE) { 515 vm_object_vndeallocate(object); 516 return; 517 } 518 519 KASSERT(object->ref_count != 0, 520 ("vm_object_deallocate: object deallocated too many times: %d", object->type)); 521 522 /* 523 * If the reference count goes to 0 we start calling 524 * vm_object_terminate() on the object chain. 525 * A ref count of 1 may be a special case depending on the 526 * shadow count being 0 or 1. 527 */ 528 object->ref_count--; 529 if (object->ref_count > 1) { 530 VM_OBJECT_WUNLOCK(object); 531 return; 532 } else if (object->ref_count == 1) { 533 if (object->type == OBJT_SWAP && 534 (object->flags & OBJ_TMPFS) != 0) { 535 vp = object->un_pager.swp.swp_tmpfs; 536 vhold(vp); 537 VM_OBJECT_WUNLOCK(object); 538 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY); 539 VM_OBJECT_WLOCK(object); 540 if (object->type == OBJT_DEAD || 541 object->ref_count != 1) { 542 VM_OBJECT_WUNLOCK(object); 543 VOP_UNLOCK(vp, 0); 544 vdrop(vp); 545 return; 546 } 547 if ((object->flags & OBJ_TMPFS) != 0) 548 VOP_UNSET_TEXT(vp); 549 VOP_UNLOCK(vp, 0); 550 vdrop(vp); 551 } 552 if (object->shadow_count == 0 && 553 object->handle == NULL && 554 (object->type == OBJT_DEFAULT || 555 (object->type == OBJT_SWAP && 556 (object->flags & OBJ_TMPFS_NODE) == 0))) { 557 vm_object_set_flag(object, OBJ_ONEMAPPING); 558 } else if ((object->shadow_count == 1) && 559 (object->handle == NULL) && 560 (object->type == OBJT_DEFAULT || 561 object->type == OBJT_SWAP)) { 562 vm_object_t robject; 563 564 robject = LIST_FIRST(&object->shadow_head); 565 KASSERT(robject != NULL, 566 ("vm_object_deallocate: ref_count: %d, shadow_count: %d", 567 object->ref_count, 568 object->shadow_count)); 569 KASSERT((robject->flags & OBJ_TMPFS_NODE) == 0, 570 ("shadowed tmpfs v_object %p", object)); 571 if (!VM_OBJECT_TRYWLOCK(robject)) { 572 /* 573 * Avoid a potential deadlock. 574 */ 575 object->ref_count++; 576 VM_OBJECT_WUNLOCK(object); 577 /* 578 * More likely than not the thread 579 * holding robject's lock has lower 580 * priority than the current thread. 581 * Let the lower priority thread run. 582 */ 583 pause("vmo_de", 1); 584 continue; 585 } 586 /* 587 * Collapse object into its shadow unless its 588 * shadow is dead. In that case, object will 589 * be deallocated by the thread that is 590 * deallocating its shadow. 591 */ 592 if ((robject->flags & OBJ_DEAD) == 0 && 593 (robject->handle == NULL) && 594 (robject->type == OBJT_DEFAULT || 595 robject->type == OBJT_SWAP)) { 596 597 robject->ref_count++; 598retry: 599 if (robject->paging_in_progress) { 600 VM_OBJECT_WUNLOCK(object); 601 vm_object_pip_wait(robject, 602 "objde1"); 603 temp = robject->backing_object; 604 if (object == temp) { 605 VM_OBJECT_WLOCK(object); 606 goto retry; 607 } 608 } else if (object->paging_in_progress) { 609 VM_OBJECT_WUNLOCK(robject); 610 object->flags |= OBJ_PIPWNT; 611 VM_OBJECT_SLEEP(object, object, 612 PDROP | PVM, "objde2", 0); 613 VM_OBJECT_WLOCK(robject); 614 temp = robject->backing_object; 615 if (object == temp) { 616 VM_OBJECT_WLOCK(object); 617 goto retry; 618 } 619 } else 620 VM_OBJECT_WUNLOCK(object); 621 622 if (robject->ref_count == 1) { 623 robject->ref_count--; 624 object = robject; 625 goto doterm; 626 } 627 object = robject; 628 vm_object_collapse(object); 629 VM_OBJECT_WUNLOCK(object); 630 continue; 631 } 632 VM_OBJECT_WUNLOCK(robject); 633 } 634 VM_OBJECT_WUNLOCK(object); 635 return; 636 } 637doterm: 638 temp = object->backing_object; 639 if (temp != NULL) { 640 KASSERT((object->flags & OBJ_TMPFS_NODE) == 0, 641 ("shadowed tmpfs v_object 2 %p", object)); 642 VM_OBJECT_WLOCK(temp); 643 LIST_REMOVE(object, shadow_list); 644 temp->shadow_count--; 645 VM_OBJECT_WUNLOCK(temp); 646 object->backing_object = NULL; 647 } 648 /* 649 * Don't double-terminate, we could be in a termination 650 * recursion due to the terminate having to sync data 651 * to disk. 652 */ 653 if ((object->flags & OBJ_DEAD) == 0) 654 vm_object_terminate(object); 655 else 656 VM_OBJECT_WUNLOCK(object); 657 object = temp; 658 } 659} 660 661/* 662 * vm_object_destroy removes the object from the global object list 663 * and frees the space for the object. 664 */ 665void 666vm_object_destroy(vm_object_t object) 667{ 668 669 /* 670 * Remove the object from the global object list. 671 */ 672 mtx_lock(&vm_object_list_mtx); 673 TAILQ_REMOVE(&vm_object_list, object, object_list); 674 mtx_unlock(&vm_object_list_mtx); 675 676 /* 677 * Release the allocation charge. 678 */ 679 if (object->cred != NULL) { 680 KASSERT(object->type == OBJT_DEFAULT || 681 object->type == OBJT_SWAP, 682 ("vm_object_terminate: non-swap obj %p has cred", 683 object)); 684 swap_release_by_cred(object->charge, object->cred); 685 object->charge = 0; 686 crfree(object->cred); 687 object->cred = NULL; 688 } 689 690 /* 691 * Free the space for the object. 692 */ 693 uma_zfree(obj_zone, object); 694} 695 696/* 697 * vm_object_terminate actually destroys the specified object, freeing 698 * up all previously used resources. 699 * 700 * The object must be locked. 701 * This routine may block. 702 */ 703void 704vm_object_terminate(vm_object_t object) 705{ 706 vm_page_t p, p_next; 707 708 VM_OBJECT_ASSERT_WLOCKED(object); 709 710 /* 711 * Make sure no one uses us. 712 */ 713 vm_object_set_flag(object, OBJ_DEAD); 714 715 /* 716 * wait for the pageout daemon to be done with the object 717 */ 718 vm_object_pip_wait(object, "objtrm"); 719 720 KASSERT(!object->paging_in_progress, 721 ("vm_object_terminate: pageout in progress")); 722 723 /* 724 * Clean and free the pages, as appropriate. All references to the 725 * object are gone, so we don't need to lock it. 726 */ 727 if (object->type == OBJT_VNODE) { 728 struct vnode *vp = (struct vnode *)object->handle; 729 730 /* 731 * Clean pages and flush buffers. 732 */ 733 vm_object_page_clean(object, 0, 0, OBJPC_SYNC); 734 VM_OBJECT_WUNLOCK(object); 735 736 vinvalbuf(vp, V_SAVE, 0, 0); 737 738 VM_OBJECT_WLOCK(object); 739 } 740 741 KASSERT(object->ref_count == 0, 742 ("vm_object_terminate: object with references, ref_count=%d", 743 object->ref_count)); 744 745 /* 746 * Free any remaining pageable pages. This also removes them from the 747 * paging queues. However, don't free wired pages, just remove them 748 * from the object. Rather than incrementally removing each page from 749 * the object, the page and object are reset to any empty state. 750 */ 751 TAILQ_FOREACH_SAFE(p, &object->memq, listq, p_next) { 752 vm_page_assert_unbusied(p); 753 vm_page_lock(p); 754 /* 755 * Optimize the page's removal from the object by resetting 756 * its "object" field. Specifically, if the page is not 757 * wired, then the effect of this assignment is that 758 * vm_page_free()'s call to vm_page_remove() will return 759 * immediately without modifying the page or the object. 760 */ 761 p->object = NULL; 762 if (p->wire_count == 0) { 763 vm_page_free(p); 764 PCPU_INC(cnt.v_pfree); 765 } 766 vm_page_unlock(p); 767 } 768 /* 769 * If the object contained any pages, then reset it to an empty state. 770 * None of the object's fields, including "resident_page_count", were 771 * modified by the preceding loop. 772 */ 773 if (object->resident_page_count != 0) { 774 vm_radix_reclaim_allnodes(&object->rtree); 775 TAILQ_INIT(&object->memq); 776 object->resident_page_count = 0; 777 if (object->type == OBJT_VNODE) 778 vdrop(object->handle); 779 } 780 781#if VM_NRESERVLEVEL > 0 782 if (__predict_false(!LIST_EMPTY(&object->rvq))) 783 vm_reserv_break_all(object); 784#endif 785 if (__predict_false(!vm_object_cache_is_empty(object))) 786 vm_page_cache_free(object, 0, 0); 787 788 /* 789 * Let the pager know object is dead. 790 */ 791 vm_pager_deallocate(object); 792 VM_OBJECT_WUNLOCK(object); 793 794 vm_object_destroy(object); 795} 796 797/* 798 * Make the page read-only so that we can clear the object flags. However, if 799 * this is a nosync mmap then the object is likely to stay dirty so do not 800 * mess with the page and do not clear the object flags. Returns TRUE if the 801 * page should be flushed, and FALSE otherwise. 802 */ 803static boolean_t 804vm_object_page_remove_write(vm_page_t p, int flags, boolean_t *clearobjflags) 805{ 806 807 /* 808 * If we have been asked to skip nosync pages and this is a 809 * nosync page, skip it. Note that the object flags were not 810 * cleared in this case so we do not have to set them. 811 */ 812 if ((flags & OBJPC_NOSYNC) != 0 && (p->oflags & VPO_NOSYNC) != 0) { 813 *clearobjflags = FALSE; 814 return (FALSE); 815 } else { 816 pmap_remove_write(p); 817 return (p->dirty != 0); 818 } 819} 820 821/* 822 * vm_object_page_clean 823 * 824 * Clean all dirty pages in the specified range of object. Leaves page 825 * on whatever queue it is currently on. If NOSYNC is set then do not 826 * write out pages with VPO_NOSYNC set (originally comes from MAP_NOSYNC), 827 * leaving the object dirty. 828 * 829 * When stuffing pages asynchronously, allow clustering. XXX we need a 830 * synchronous clustering mode implementation. 831 * 832 * Odd semantics: if start == end, we clean everything. 833 * 834 * The object must be locked. 835 * 836 * Returns FALSE if some page from the range was not written, as 837 * reported by the pager, and TRUE otherwise. 838 */ 839boolean_t 840vm_object_page_clean(vm_object_t object, vm_ooffset_t start, vm_ooffset_t end, 841 int flags) 842{ 843 vm_page_t np, p; 844 vm_pindex_t pi, tend, tstart; 845 int curgeneration, n, pagerflags; 846 boolean_t clearobjflags, eio, res; 847 848 VM_OBJECT_ASSERT_WLOCKED(object); 849 850 /* 851 * The OBJ_MIGHTBEDIRTY flag is only set for OBJT_VNODE 852 * objects. The check below prevents the function from 853 * operating on non-vnode objects. 854 */ 855 if ((object->flags & OBJ_MIGHTBEDIRTY) == 0 || 856 object->resident_page_count == 0) 857 return (TRUE); 858 859 pagerflags = (flags & (OBJPC_SYNC | OBJPC_INVAL)) != 0 ? 860 VM_PAGER_PUT_SYNC : VM_PAGER_CLUSTER_OK; 861 pagerflags |= (flags & OBJPC_INVAL) != 0 ? VM_PAGER_PUT_INVAL : 0; 862 863 tstart = OFF_TO_IDX(start); 864 tend = (end == 0) ? object->size : OFF_TO_IDX(end + PAGE_MASK); 865 clearobjflags = tstart == 0 && tend >= object->size; 866 res = TRUE; 867 868rescan: 869 curgeneration = object->generation; 870 871 for (p = vm_page_find_least(object, tstart); p != NULL; p = np) { 872 pi = p->pindex; 873 if (pi >= tend) 874 break; 875 np = TAILQ_NEXT(p, listq); 876 if (p->valid == 0) 877 continue; 878 if (vm_page_sleep_if_busy(p, "vpcwai")) { 879 if (object->generation != curgeneration) { 880 if ((flags & OBJPC_SYNC) != 0) 881 goto rescan; 882 else 883 clearobjflags = FALSE; 884 } 885 np = vm_page_find_least(object, pi); 886 continue; 887 } 888 if (!vm_object_page_remove_write(p, flags, &clearobjflags)) 889 continue; 890 891 n = vm_object_page_collect_flush(object, p, pagerflags, 892 flags, &clearobjflags, &eio); 893 if (eio) { 894 res = FALSE; 895 clearobjflags = FALSE; 896 } 897 if (object->generation != curgeneration) { 898 if ((flags & OBJPC_SYNC) != 0) 899 goto rescan; 900 else 901 clearobjflags = FALSE; 902 } 903 904 /* 905 * If the VOP_PUTPAGES() did a truncated write, so 906 * that even the first page of the run is not fully 907 * written, vm_pageout_flush() returns 0 as the run 908 * length. Since the condition that caused truncated 909 * write may be permanent, e.g. exhausted free space, 910 * accepting n == 0 would cause an infinite loop. 911 * 912 * Forwarding the iterator leaves the unwritten page 913 * behind, but there is not much we can do there if 914 * filesystem refuses to write it. 915 */ 916 if (n == 0) { 917 n = 1; 918 clearobjflags = FALSE; 919 } 920 np = vm_page_find_least(object, pi + n); 921 } 922#if 0 923 VOP_FSYNC(vp, (pagerflags & VM_PAGER_PUT_SYNC) ? MNT_WAIT : 0); 924#endif 925 926 if (clearobjflags) 927 vm_object_clear_flag(object, OBJ_MIGHTBEDIRTY); 928 return (res); 929} 930 931static int 932vm_object_page_collect_flush(vm_object_t object, vm_page_t p, int pagerflags, 933 int flags, boolean_t *clearobjflags, boolean_t *eio) 934{ 935 vm_page_t ma[vm_pageout_page_count], p_first, tp; 936 int count, i, mreq, runlen; 937 938 vm_page_lock_assert(p, MA_NOTOWNED); 939 VM_OBJECT_ASSERT_WLOCKED(object); 940 941 count = 1; 942 mreq = 0; 943 944 for (tp = p; count < vm_pageout_page_count; count++) { 945 tp = vm_page_next(tp); 946 if (tp == NULL || vm_page_busied(tp)) 947 break; 948 if (!vm_object_page_remove_write(tp, flags, clearobjflags)) 949 break; 950 } 951 952 for (p_first = p; count < vm_pageout_page_count; count++) { 953 tp = vm_page_prev(p_first); 954 if (tp == NULL || vm_page_busied(tp)) 955 break; 956 if (!vm_object_page_remove_write(tp, flags, clearobjflags)) 957 break; 958 p_first = tp; 959 mreq++; 960 } 961 962 for (tp = p_first, i = 0; i < count; tp = TAILQ_NEXT(tp, listq), i++) 963 ma[i] = tp; 964 965 vm_pageout_flush(ma, count, pagerflags, mreq, &runlen, eio); 966 return (runlen); 967} 968 969/* 970 * Note that there is absolutely no sense in writing out 971 * anonymous objects, so we track down the vnode object 972 * to write out. 973 * We invalidate (remove) all pages from the address space 974 * for semantic correctness. 975 * 976 * If the backing object is a device object with unmanaged pages, then any 977 * mappings to the specified range of pages must be removed before this 978 * function is called. 979 * 980 * Note: certain anonymous maps, such as MAP_NOSYNC maps, 981 * may start out with a NULL object. 982 */ 983boolean_t 984vm_object_sync(vm_object_t object, vm_ooffset_t offset, vm_size_t size, 985 boolean_t syncio, boolean_t invalidate) 986{ 987 vm_object_t backing_object; 988 struct vnode *vp; 989 struct mount *mp; 990 int error, flags, fsync_after; 991 boolean_t res; 992 993 if (object == NULL) 994 return (TRUE); 995 res = TRUE; 996 error = 0; 997 VM_OBJECT_WLOCK(object); 998 while ((backing_object = object->backing_object) != NULL) { 999 VM_OBJECT_WLOCK(backing_object); 1000 offset += object->backing_object_offset; 1001 VM_OBJECT_WUNLOCK(object); 1002 object = backing_object; 1003 if (object->size < OFF_TO_IDX(offset + size)) 1004 size = IDX_TO_OFF(object->size) - offset; 1005 } 1006 /* 1007 * Flush pages if writing is allowed, invalidate them 1008 * if invalidation requested. Pages undergoing I/O 1009 * will be ignored by vm_object_page_remove(). 1010 * 1011 * We cannot lock the vnode and then wait for paging 1012 * to complete without deadlocking against vm_fault. 1013 * Instead we simply call vm_object_page_remove() and 1014 * allow it to block internally on a page-by-page 1015 * basis when it encounters pages undergoing async 1016 * I/O. 1017 */ 1018 if (object->type == OBJT_VNODE && 1019 (object->flags & OBJ_MIGHTBEDIRTY) != 0) { 1020 vp = object->handle; 1021 VM_OBJECT_WUNLOCK(object); 1022 (void) vn_start_write(vp, &mp, V_WAIT); 1023 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY); 1024 if (syncio && !invalidate && offset == 0 && 1025 OFF_TO_IDX(size) == object->size) { 1026 /* 1027 * If syncing the whole mapping of the file, 1028 * it is faster to schedule all the writes in 1029 * async mode, also allowing the clustering, 1030 * and then wait for i/o to complete. 1031 */ 1032 flags = 0; 1033 fsync_after = TRUE; 1034 } else { 1035 flags = (syncio || invalidate) ? OBJPC_SYNC : 0; 1036 flags |= invalidate ? (OBJPC_SYNC | OBJPC_INVAL) : 0; 1037 fsync_after = FALSE; 1038 } 1039 VM_OBJECT_WLOCK(object); 1040 res = vm_object_page_clean(object, offset, offset + size, 1041 flags); 1042 VM_OBJECT_WUNLOCK(object); 1043 if (fsync_after) 1044 error = VOP_FSYNC(vp, MNT_WAIT, curthread); 1045 VOP_UNLOCK(vp, 0); 1046 vn_finished_write(mp); 1047 if (error != 0) 1048 res = FALSE; 1049 VM_OBJECT_WLOCK(object); 1050 } 1051 if ((object->type == OBJT_VNODE || 1052 object->type == OBJT_DEVICE) && invalidate) { 1053 if (object->type == OBJT_DEVICE) 1054 /* 1055 * The option OBJPR_NOTMAPPED must be passed here 1056 * because vm_object_page_remove() cannot remove 1057 * unmanaged mappings. 1058 */ 1059 flags = OBJPR_NOTMAPPED; 1060 else if (old_msync) 1061 flags = OBJPR_NOTWIRED; 1062 else 1063 flags = OBJPR_CLEANONLY | OBJPR_NOTWIRED; 1064 vm_object_page_remove(object, OFF_TO_IDX(offset), 1065 OFF_TO_IDX(offset + size + PAGE_MASK), flags); 1066 } 1067 VM_OBJECT_WUNLOCK(object); 1068 return (res); 1069} 1070 1071/* 1072 * vm_object_madvise: 1073 * 1074 * Implements the madvise function at the object/page level. 1075 * 1076 * MADV_WILLNEED (any object) 1077 * 1078 * Activate the specified pages if they are resident. 1079 * 1080 * MADV_DONTNEED (any object) 1081 * 1082 * Deactivate the specified pages if they are resident. 1083 * 1084 * MADV_FREE (OBJT_DEFAULT/OBJT_SWAP objects, 1085 * OBJ_ONEMAPPING only) 1086 * 1087 * Deactivate and clean the specified pages if they are 1088 * resident. This permits the process to reuse the pages 1089 * without faulting or the kernel to reclaim the pages 1090 * without I/O. 1091 */ 1092void 1093vm_object_madvise(vm_object_t object, vm_pindex_t pindex, vm_pindex_t end, 1094 int advise) 1095{ 1096 vm_pindex_t tpindex; 1097 vm_object_t backing_object, tobject; 1098 vm_page_t m; 1099 1100 if (object == NULL) 1101 return; 1102 VM_OBJECT_WLOCK(object); 1103 /* 1104 * Locate and adjust resident pages 1105 */ 1106 for (; pindex < end; pindex += 1) { 1107relookup: 1108 tobject = object; 1109 tpindex = pindex; 1110shadowlookup: 1111 /* 1112 * MADV_FREE only operates on OBJT_DEFAULT or OBJT_SWAP pages 1113 * and those pages must be OBJ_ONEMAPPING. 1114 */ 1115 if (advise == MADV_FREE) { 1116 if ((tobject->type != OBJT_DEFAULT && 1117 tobject->type != OBJT_SWAP) || 1118 (tobject->flags & OBJ_ONEMAPPING) == 0) { 1119 goto unlock_tobject; 1120 } 1121 } else if ((tobject->flags & OBJ_UNMANAGED) != 0) 1122 goto unlock_tobject; 1123 m = vm_page_lookup(tobject, tpindex); 1124 if (m == NULL && advise == MADV_WILLNEED) { 1125 /* 1126 * If the page is cached, reactivate it. 1127 */ 1128 m = vm_page_alloc(tobject, tpindex, VM_ALLOC_IFCACHED | 1129 VM_ALLOC_NOBUSY); 1130 } 1131 if (m == NULL) { 1132 /* 1133 * There may be swap even if there is no backing page 1134 */ 1135 if (advise == MADV_FREE && tobject->type == OBJT_SWAP) 1136 swap_pager_freespace(tobject, tpindex, 1); 1137 /* 1138 * next object 1139 */ 1140 backing_object = tobject->backing_object; 1141 if (backing_object == NULL) 1142 goto unlock_tobject; 1143 VM_OBJECT_WLOCK(backing_object); 1144 tpindex += OFF_TO_IDX(tobject->backing_object_offset); 1145 if (tobject != object) 1146 VM_OBJECT_WUNLOCK(tobject); 1147 tobject = backing_object; 1148 goto shadowlookup; 1149 } else if (m->valid != VM_PAGE_BITS_ALL) 1150 goto unlock_tobject; 1151 /* 1152 * If the page is not in a normal state, skip it. 1153 */ 1154 vm_page_lock(m); 1155 if (m->hold_count != 0 || m->wire_count != 0) { 1156 vm_page_unlock(m); 1157 goto unlock_tobject; 1158 } 1159 KASSERT((m->flags & PG_FICTITIOUS) == 0, 1160 ("vm_object_madvise: page %p is fictitious", m)); 1161 KASSERT((m->oflags & VPO_UNMANAGED) == 0, 1162 ("vm_object_madvise: page %p is not managed", m)); 1163 if (vm_page_busied(m)) { 1164 if (advise == MADV_WILLNEED) { 1165 /* 1166 * Reference the page before unlocking and 1167 * sleeping so that the page daemon is less 1168 * likely to reclaim it. 1169 */ 1170 vm_page_aflag_set(m, PGA_REFERENCED); 1171 } 1172 if (object != tobject) 1173 VM_OBJECT_WUNLOCK(object); 1174 VM_OBJECT_WUNLOCK(tobject); 1175 vm_page_busy_sleep(m, "madvpo"); 1176 VM_OBJECT_WLOCK(object); 1177 goto relookup; 1178 } 1179 if (advise == MADV_WILLNEED) { 1180 vm_page_activate(m); 1181 } else { 1182 vm_page_advise(m, advise); 1183 } 1184 vm_page_unlock(m); 1185 if (advise == MADV_FREE && tobject->type == OBJT_SWAP) 1186 swap_pager_freespace(tobject, tpindex, 1); 1187unlock_tobject: 1188 if (tobject != object) 1189 VM_OBJECT_WUNLOCK(tobject); 1190 } 1191 VM_OBJECT_WUNLOCK(object); 1192} 1193 1194/* 1195 * vm_object_shadow: 1196 * 1197 * Create a new object which is backed by the 1198 * specified existing object range. The source 1199 * object reference is deallocated. 1200 * 1201 * The new object and offset into that object 1202 * are returned in the source parameters. 1203 */ 1204void 1205vm_object_shadow( 1206 vm_object_t *object, /* IN/OUT */ 1207 vm_ooffset_t *offset, /* IN/OUT */ 1208 vm_size_t length) 1209{ 1210 vm_object_t source; 1211 vm_object_t result; 1212 1213 source = *object; 1214 1215 /* 1216 * Don't create the new object if the old object isn't shared. 1217 */ 1218 if (source != NULL) { 1219 VM_OBJECT_WLOCK(source); 1220 if (source->ref_count == 1 && 1221 source->handle == NULL && 1222 (source->type == OBJT_DEFAULT || 1223 source->type == OBJT_SWAP)) { 1224 VM_OBJECT_WUNLOCK(source); 1225 return; 1226 } 1227 VM_OBJECT_WUNLOCK(source); 1228 } 1229 1230 /* 1231 * Allocate a new object with the given length. 1232 */ 1233 result = vm_object_allocate(OBJT_DEFAULT, atop(length)); 1234 1235 /* 1236 * The new object shadows the source object, adding a reference to it. 1237 * Our caller changes his reference to point to the new object, 1238 * removing a reference to the source object. Net result: no change 1239 * of reference count. 1240 * 1241 * Try to optimize the result object's page color when shadowing 1242 * in order to maintain page coloring consistency in the combined 1243 * shadowed object. 1244 */ 1245 result->backing_object = source; 1246 /* 1247 * Store the offset into the source object, and fix up the offset into 1248 * the new object. 1249 */ 1250 result->backing_object_offset = *offset; 1251 if (source != NULL) { 1252 VM_OBJECT_WLOCK(source); 1253 LIST_INSERT_HEAD(&source->shadow_head, result, shadow_list); 1254 source->shadow_count++; 1255#if VM_NRESERVLEVEL > 0 1256 result->flags |= source->flags & OBJ_COLORED; 1257 result->pg_color = (source->pg_color + OFF_TO_IDX(*offset)) & 1258 ((1 << (VM_NFREEORDER - 1)) - 1); 1259#endif 1260 VM_OBJECT_WUNLOCK(source); 1261 } 1262 1263 1264 /* 1265 * Return the new things 1266 */ 1267 *offset = 0; 1268 *object = result; 1269} 1270 1271/* 1272 * vm_object_split: 1273 * 1274 * Split the pages in a map entry into a new object. This affords 1275 * easier removal of unused pages, and keeps object inheritance from 1276 * being a negative impact on memory usage. 1277 */ 1278void 1279vm_object_split(vm_map_entry_t entry) 1280{ 1281 vm_page_t m, m_next; 1282 vm_object_t orig_object, new_object, source; 1283 vm_pindex_t idx, offidxstart; 1284 vm_size_t size; 1285 1286 orig_object = entry->object.vm_object; 1287 if (orig_object->type != OBJT_DEFAULT && orig_object->type != OBJT_SWAP) 1288 return; 1289 if (orig_object->ref_count <= 1) 1290 return; 1291 VM_OBJECT_WUNLOCK(orig_object); 1292 1293 offidxstart = OFF_TO_IDX(entry->offset); 1294 size = atop(entry->end - entry->start); 1295 1296 /* 1297 * If swap_pager_copy() is later called, it will convert new_object 1298 * into a swap object. 1299 */ 1300 new_object = vm_object_allocate(OBJT_DEFAULT, size); 1301 1302 /* 1303 * At this point, the new object is still private, so the order in 1304 * which the original and new objects are locked does not matter. 1305 */ 1306 VM_OBJECT_WLOCK(new_object); 1307 VM_OBJECT_WLOCK(orig_object); 1308 source = orig_object->backing_object; 1309 if (source != NULL) { 1310 VM_OBJECT_WLOCK(source); 1311 if ((source->flags & OBJ_DEAD) != 0) { 1312 VM_OBJECT_WUNLOCK(source); 1313 VM_OBJECT_WUNLOCK(orig_object); 1314 VM_OBJECT_WUNLOCK(new_object); 1315 vm_object_deallocate(new_object); 1316 VM_OBJECT_WLOCK(orig_object); 1317 return; 1318 } 1319 LIST_INSERT_HEAD(&source->shadow_head, 1320 new_object, shadow_list); 1321 source->shadow_count++; 1322 vm_object_reference_locked(source); /* for new_object */ 1323 vm_object_clear_flag(source, OBJ_ONEMAPPING); 1324 VM_OBJECT_WUNLOCK(source); 1325 new_object->backing_object_offset = 1326 orig_object->backing_object_offset + entry->offset; 1327 new_object->backing_object = source; 1328 } 1329 if (orig_object->cred != NULL) { 1330 new_object->cred = orig_object->cred; 1331 crhold(orig_object->cred); 1332 new_object->charge = ptoa(size); 1333 KASSERT(orig_object->charge >= ptoa(size), 1334 ("orig_object->charge < 0")); 1335 orig_object->charge -= ptoa(size); 1336 } 1337retry: 1338 m = vm_page_find_least(orig_object, offidxstart); 1339 for (; m != NULL && (idx = m->pindex - offidxstart) < size; 1340 m = m_next) { 1341 m_next = TAILQ_NEXT(m, listq); 1342 1343 /* 1344 * We must wait for pending I/O to complete before we can 1345 * rename the page. 1346 * 1347 * We do not have to VM_PROT_NONE the page as mappings should 1348 * not be changed by this operation. 1349 */ 1350 if (vm_page_busied(m)) { 1351 VM_OBJECT_WUNLOCK(new_object); 1352 vm_page_lock(m); 1353 VM_OBJECT_WUNLOCK(orig_object); 1354 vm_page_busy_sleep(m, "spltwt"); 1355 VM_OBJECT_WLOCK(orig_object); 1356 VM_OBJECT_WLOCK(new_object); 1357 goto retry; 1358 } 1359 1360 /* vm_page_rename() will handle dirty and cache. */ 1361 if (vm_page_rename(m, new_object, idx)) { 1362 VM_OBJECT_WUNLOCK(new_object); 1363 VM_OBJECT_WUNLOCK(orig_object); 1364 VM_WAIT; 1365 VM_OBJECT_WLOCK(orig_object); 1366 VM_OBJECT_WLOCK(new_object); 1367 goto retry; 1368 } 1369#if VM_NRESERVLEVEL > 0 1370 /* 1371 * If some of the reservation's allocated pages remain with 1372 * the original object, then transferring the reservation to 1373 * the new object is neither particularly beneficial nor 1374 * particularly harmful as compared to leaving the reservation 1375 * with the original object. If, however, all of the 1376 * reservation's allocated pages are transferred to the new 1377 * object, then transferring the reservation is typically 1378 * beneficial. Determining which of these two cases applies 1379 * would be more costly than unconditionally renaming the 1380 * reservation. 1381 */ 1382 vm_reserv_rename(m, new_object, orig_object, offidxstart); 1383#endif 1384 if (orig_object->type == OBJT_SWAP) 1385 vm_page_xbusy(m); 1386 } 1387 if (orig_object->type == OBJT_SWAP) { 1388 /* 1389 * swap_pager_copy() can sleep, in which case the orig_object's 1390 * and new_object's locks are released and reacquired. 1391 */ 1392 swap_pager_copy(orig_object, new_object, offidxstart, 0); 1393 TAILQ_FOREACH(m, &new_object->memq, listq) 1394 vm_page_xunbusy(m); 1395 1396 /* 1397 * Transfer any cached pages from orig_object to new_object. 1398 * If swap_pager_copy() found swapped out pages within the 1399 * specified range of orig_object, then it changed 1400 * new_object's type to OBJT_SWAP when it transferred those 1401 * pages to new_object. Otherwise, new_object's type 1402 * should still be OBJT_DEFAULT and orig_object should not 1403 * contain any cached pages within the specified range. 1404 */ 1405 if (__predict_false(!vm_object_cache_is_empty(orig_object))) 1406 vm_page_cache_transfer(orig_object, offidxstart, 1407 new_object); 1408 } 1409 VM_OBJECT_WUNLOCK(orig_object); 1410 VM_OBJECT_WUNLOCK(new_object); 1411 entry->object.vm_object = new_object; 1412 entry->offset = 0LL; 1413 vm_object_deallocate(orig_object); 1414 VM_OBJECT_WLOCK(new_object); 1415} 1416 1417#define OBSC_TEST_ALL_SHADOWED 0x0001 1418#define OBSC_COLLAPSE_NOWAIT 0x0002 1419#define OBSC_COLLAPSE_WAIT 0x0004 1420 1421static int 1422vm_object_backing_scan(vm_object_t object, int op) 1423{ 1424 int r = 1; 1425 vm_page_t p; 1426 vm_object_t backing_object; 1427 vm_pindex_t backing_offset_index; 1428 1429 VM_OBJECT_ASSERT_WLOCKED(object); 1430 VM_OBJECT_ASSERT_WLOCKED(object->backing_object); 1431 1432 backing_object = object->backing_object; 1433 backing_offset_index = OFF_TO_IDX(object->backing_object_offset); 1434 1435 /* 1436 * Initial conditions 1437 */ 1438 if (op & OBSC_TEST_ALL_SHADOWED) { 1439 /* 1440 * We do not want to have to test for the existence of cache 1441 * or swap pages in the backing object. XXX but with the 1442 * new swapper this would be pretty easy to do. 1443 * 1444 * XXX what about anonymous MAP_SHARED memory that hasn't 1445 * been ZFOD faulted yet? If we do not test for this, the 1446 * shadow test may succeed! XXX 1447 */ 1448 if (backing_object->type != OBJT_DEFAULT) { 1449 return (0); 1450 } 1451 } 1452 if (op & OBSC_COLLAPSE_WAIT) { 1453 vm_object_set_flag(backing_object, OBJ_DEAD); 1454 } 1455 1456 /* 1457 * Our scan 1458 */ 1459 p = TAILQ_FIRST(&backing_object->memq); 1460 while (p) { 1461 vm_page_t next = TAILQ_NEXT(p, listq); 1462 vm_pindex_t new_pindex = p->pindex - backing_offset_index; 1463 1464 if (op & OBSC_TEST_ALL_SHADOWED) { 1465 vm_page_t pp; 1466 1467 /* 1468 * Ignore pages outside the parent object's range 1469 * and outside the parent object's mapping of the 1470 * backing object. 1471 * 1472 * note that we do not busy the backing object's 1473 * page. 1474 */ 1475 if ( 1476 p->pindex < backing_offset_index || 1477 new_pindex >= object->size 1478 ) { 1479 p = next; 1480 continue; 1481 } 1482 1483 /* 1484 * See if the parent has the page or if the parent's 1485 * object pager has the page. If the parent has the 1486 * page but the page is not valid, the parent's 1487 * object pager must have the page. 1488 * 1489 * If this fails, the parent does not completely shadow 1490 * the object and we might as well give up now. 1491 */ 1492 1493 pp = vm_page_lookup(object, new_pindex); 1494 if ( 1495 (pp == NULL || pp->valid == 0) && 1496 !vm_pager_has_page(object, new_pindex, NULL, NULL) 1497 ) { 1498 r = 0; 1499 break; 1500 } 1501 } 1502 1503 /* 1504 * Check for busy page 1505 */ 1506 if (op & (OBSC_COLLAPSE_WAIT | OBSC_COLLAPSE_NOWAIT)) { 1507 vm_page_t pp; 1508 1509 if (op & OBSC_COLLAPSE_NOWAIT) { 1510 if (!p->valid || vm_page_busied(p)) { 1511 p = next; 1512 continue; 1513 } 1514 } else if (op & OBSC_COLLAPSE_WAIT) { 1515 if (vm_page_busied(p)) { 1516 VM_OBJECT_WUNLOCK(object); 1517 vm_page_lock(p); 1518 VM_OBJECT_WUNLOCK(backing_object); 1519 vm_page_busy_sleep(p, "vmocol"); 1520 VM_OBJECT_WLOCK(object); 1521 VM_OBJECT_WLOCK(backing_object); 1522 /* 1523 * If we slept, anything could have 1524 * happened. Since the object is 1525 * marked dead, the backing offset 1526 * should not have changed so we 1527 * just restart our scan. 1528 */ 1529 p = TAILQ_FIRST(&backing_object->memq); 1530 continue; 1531 } 1532 } 1533 1534 KASSERT( 1535 p->object == backing_object, 1536 ("vm_object_backing_scan: object mismatch") 1537 ); 1538 1539 if ( 1540 p->pindex < backing_offset_index || 1541 new_pindex >= object->size 1542 ) { 1543 if (backing_object->type == OBJT_SWAP) 1544 swap_pager_freespace(backing_object, 1545 p->pindex, 1); 1546 1547 /* 1548 * Page is out of the parent object's range, we 1549 * can simply destroy it. 1550 */ 1551 vm_page_lock(p); 1552 KASSERT(!pmap_page_is_mapped(p), 1553 ("freeing mapped page %p", p)); 1554 if (p->wire_count == 0) 1555 vm_page_free(p); 1556 else 1557 vm_page_remove(p); 1558 vm_page_unlock(p); 1559 p = next; 1560 continue; 1561 } 1562 1563 pp = vm_page_lookup(object, new_pindex); 1564 if ( 1565 (op & OBSC_COLLAPSE_NOWAIT) != 0 && 1566 (pp != NULL && pp->valid == 0) 1567 ) { 1568 if (backing_object->type == OBJT_SWAP) 1569 swap_pager_freespace(backing_object, 1570 p->pindex, 1); 1571 1572 /* 1573 * The page in the parent is not (yet) valid. 1574 * We don't know anything about the state of 1575 * the original page. It might be mapped, 1576 * so we must avoid the next if here. 1577 * 1578 * This is due to a race in vm_fault() where 1579 * we must unbusy the original (backing_obj) 1580 * page before we can (re)lock the parent. 1581 * Hence we can get here. 1582 */ 1583 p = next; 1584 continue; 1585 } 1586 if ( 1587 pp != NULL || 1588 vm_pager_has_page(object, new_pindex, NULL, NULL) 1589 ) { 1590 if (backing_object->type == OBJT_SWAP) 1591 swap_pager_freespace(backing_object, 1592 p->pindex, 1); 1593 1594 /* 1595 * page already exists in parent OR swap exists 1596 * for this location in the parent. Destroy 1597 * the original page from the backing object. 1598 * 1599 * Leave the parent's page alone 1600 */ 1601 vm_page_lock(p); 1602 KASSERT(!pmap_page_is_mapped(p), 1603 ("freeing mapped page %p", p)); 1604 if (p->wire_count == 0) 1605 vm_page_free(p); 1606 else 1607 vm_page_remove(p); 1608 vm_page_unlock(p); 1609 p = next; 1610 continue; 1611 } 1612 1613 /* 1614 * Page does not exist in parent, rename the 1615 * page from the backing object to the main object. 1616 * 1617 * If the page was mapped to a process, it can remain 1618 * mapped through the rename. 1619 * vm_page_rename() will handle dirty and cache. 1620 */ 1621 if (vm_page_rename(p, object, new_pindex)) { 1622 if (op & OBSC_COLLAPSE_NOWAIT) { 1623 p = next; 1624 continue; 1625 } 1626 VM_OBJECT_WLOCK(backing_object); 1627 VM_OBJECT_WUNLOCK(object); 1628 VM_WAIT; 1629 VM_OBJECT_WLOCK(object); 1630 VM_OBJECT_WLOCK(backing_object); 1631 p = TAILQ_FIRST(&backing_object->memq); 1632 continue; 1633 } 1634 1635 /* Use the old pindex to free the right page. */ 1636 if (backing_object->type == OBJT_SWAP) 1637 swap_pager_freespace(backing_object, 1638 new_pindex + backing_offset_index, 1); 1639 1640#if VM_NRESERVLEVEL > 0 1641 /* 1642 * Rename the reservation. 1643 */ 1644 vm_reserv_rename(p, object, backing_object, 1645 backing_offset_index); 1646#endif 1647 } 1648 p = next; 1649 } 1650 return (r); 1651} 1652 1653 1654/* 1655 * this version of collapse allows the operation to occur earlier and 1656 * when paging_in_progress is true for an object... This is not a complete 1657 * operation, but should plug 99.9% of the rest of the leaks. 1658 */ 1659static void 1660vm_object_qcollapse(vm_object_t object) 1661{ 1662 vm_object_t backing_object = object->backing_object; 1663 1664 VM_OBJECT_ASSERT_WLOCKED(object); 1665 VM_OBJECT_ASSERT_WLOCKED(backing_object); 1666 1667 if (backing_object->ref_count != 1) 1668 return; 1669 1670 vm_object_backing_scan(object, OBSC_COLLAPSE_NOWAIT); 1671} 1672 1673/* 1674 * vm_object_collapse: 1675 * 1676 * Collapse an object with the object backing it. 1677 * Pages in the backing object are moved into the 1678 * parent, and the backing object is deallocated. 1679 */ 1680void 1681vm_object_collapse(vm_object_t object) 1682{ 1683 VM_OBJECT_ASSERT_WLOCKED(object); 1684 1685 while (TRUE) { 1686 vm_object_t backing_object; 1687 1688 /* 1689 * Verify that the conditions are right for collapse: 1690 * 1691 * The object exists and the backing object exists. 1692 */ 1693 if ((backing_object = object->backing_object) == NULL) 1694 break; 1695 1696 /* 1697 * we check the backing object first, because it is most likely 1698 * not collapsable. 1699 */ 1700 VM_OBJECT_WLOCK(backing_object); 1701 if (backing_object->handle != NULL || 1702 (backing_object->type != OBJT_DEFAULT && 1703 backing_object->type != OBJT_SWAP) || 1704 (backing_object->flags & OBJ_DEAD) || 1705 object->handle != NULL || 1706 (object->type != OBJT_DEFAULT && 1707 object->type != OBJT_SWAP) || 1708 (object->flags & OBJ_DEAD)) { 1709 VM_OBJECT_WUNLOCK(backing_object); 1710 break; 1711 } 1712 1713 if ( 1714 object->paging_in_progress != 0 || 1715 backing_object->paging_in_progress != 0 1716 ) { 1717 vm_object_qcollapse(object); 1718 VM_OBJECT_WUNLOCK(backing_object); 1719 break; 1720 } 1721 /* 1722 * We know that we can either collapse the backing object (if 1723 * the parent is the only reference to it) or (perhaps) have 1724 * the parent bypass the object if the parent happens to shadow 1725 * all the resident pages in the entire backing object. 1726 * 1727 * This is ignoring pager-backed pages such as swap pages. 1728 * vm_object_backing_scan fails the shadowing test in this 1729 * case. 1730 */ 1731 if (backing_object->ref_count == 1) { 1732 /* 1733 * If there is exactly one reference to the backing 1734 * object, we can collapse it into the parent. 1735 */ 1736 vm_object_backing_scan(object, OBSC_COLLAPSE_WAIT); 1737 1738#if VM_NRESERVLEVEL > 0 1739 /* 1740 * Break any reservations from backing_object. 1741 */ 1742 if (__predict_false(!LIST_EMPTY(&backing_object->rvq))) 1743 vm_reserv_break_all(backing_object); 1744#endif 1745 1746 /* 1747 * Move the pager from backing_object to object. 1748 */ 1749 if (backing_object->type == OBJT_SWAP) { 1750 /* 1751 * swap_pager_copy() can sleep, in which case 1752 * the backing_object's and object's locks are 1753 * released and reacquired. 1754 * Since swap_pager_copy() is being asked to 1755 * destroy the source, it will change the 1756 * backing_object's type to OBJT_DEFAULT. 1757 */ 1758 swap_pager_copy( 1759 backing_object, 1760 object, 1761 OFF_TO_IDX(object->backing_object_offset), TRUE); 1762 1763 /* 1764 * Free any cached pages from backing_object. 1765 */ 1766 if (__predict_false( 1767 !vm_object_cache_is_empty(backing_object))) 1768 vm_page_cache_free(backing_object, 0, 0); 1769 } 1770 /* 1771 * Object now shadows whatever backing_object did. 1772 * Note that the reference to 1773 * backing_object->backing_object moves from within 1774 * backing_object to within object. 1775 */ 1776 LIST_REMOVE(object, shadow_list); 1777 backing_object->shadow_count--; 1778 if (backing_object->backing_object) { 1779 VM_OBJECT_WLOCK(backing_object->backing_object); 1780 LIST_REMOVE(backing_object, shadow_list); 1781 LIST_INSERT_HEAD( 1782 &backing_object->backing_object->shadow_head, 1783 object, shadow_list); 1784 /* 1785 * The shadow_count has not changed. 1786 */ 1787 VM_OBJECT_WUNLOCK(backing_object->backing_object); 1788 } 1789 object->backing_object = backing_object->backing_object; 1790 object->backing_object_offset += 1791 backing_object->backing_object_offset; 1792 1793 /* 1794 * Discard backing_object. 1795 * 1796 * Since the backing object has no pages, no pager left, 1797 * and no object references within it, all that is 1798 * necessary is to dispose of it. 1799 */ 1800 KASSERT(backing_object->ref_count == 1, ( 1801"backing_object %p was somehow re-referenced during collapse!", 1802 backing_object)); 1803 VM_OBJECT_WUNLOCK(backing_object); 1804 vm_object_destroy(backing_object); 1805 1806 object_collapses++; 1807 } else { 1808 vm_object_t new_backing_object; 1809 1810 /* 1811 * If we do not entirely shadow the backing object, 1812 * there is nothing we can do so we give up. 1813 */ 1814 if (object->resident_page_count != object->size && 1815 vm_object_backing_scan(object, 1816 OBSC_TEST_ALL_SHADOWED) == 0) { 1817 VM_OBJECT_WUNLOCK(backing_object); 1818 break; 1819 } 1820 1821 /* 1822 * Make the parent shadow the next object in the 1823 * chain. Deallocating backing_object will not remove 1824 * it, since its reference count is at least 2. 1825 */ 1826 LIST_REMOVE(object, shadow_list); 1827 backing_object->shadow_count--; 1828 1829 new_backing_object = backing_object->backing_object; 1830 if ((object->backing_object = new_backing_object) != NULL) { 1831 VM_OBJECT_WLOCK(new_backing_object); 1832 LIST_INSERT_HEAD( 1833 &new_backing_object->shadow_head, 1834 object, 1835 shadow_list 1836 ); 1837 new_backing_object->shadow_count++; 1838 vm_object_reference_locked(new_backing_object); 1839 VM_OBJECT_WUNLOCK(new_backing_object); 1840 object->backing_object_offset += 1841 backing_object->backing_object_offset; 1842 } 1843 1844 /* 1845 * Drop the reference count on backing_object. Since 1846 * its ref_count was at least 2, it will not vanish. 1847 */ 1848 backing_object->ref_count--; 1849 VM_OBJECT_WUNLOCK(backing_object); 1850 object_bypasses++; 1851 } 1852 1853 /* 1854 * Try again with this object's new backing object. 1855 */ 1856 } 1857} 1858 1859/* 1860 * vm_object_page_remove: 1861 * 1862 * For the given object, either frees or invalidates each of the 1863 * specified pages. In general, a page is freed. However, if a page is 1864 * wired for any reason other than the existence of a managed, wired 1865 * mapping, then it may be invalidated but not removed from the object. 1866 * Pages are specified by the given range ["start", "end") and the option 1867 * OBJPR_CLEANONLY. As a special case, if "end" is zero, then the range 1868 * extends from "start" to the end of the object. If the option 1869 * OBJPR_CLEANONLY is specified, then only the non-dirty pages within the 1870 * specified range are affected. If the option OBJPR_NOTMAPPED is 1871 * specified, then the pages within the specified range must have no 1872 * mappings. Otherwise, if this option is not specified, any mappings to 1873 * the specified pages are removed before the pages are freed or 1874 * invalidated. 1875 * 1876 * In general, this operation should only be performed on objects that 1877 * contain managed pages. There are, however, two exceptions. First, it 1878 * is performed on the kernel and kmem objects by vm_map_entry_delete(). 1879 * Second, it is used by msync(..., MS_INVALIDATE) to invalidate device- 1880 * backed pages. In both of these cases, the option OBJPR_CLEANONLY must 1881 * not be specified and the option OBJPR_NOTMAPPED must be specified. 1882 * 1883 * The object must be locked. 1884 */ 1885void 1886vm_object_page_remove(vm_object_t object, vm_pindex_t start, vm_pindex_t end, 1887 int options) 1888{ 1889 vm_page_t p, next; 1890 int wirings; 1891 1892 VM_OBJECT_ASSERT_WLOCKED(object); 1893 KASSERT((object->flags & OBJ_UNMANAGED) == 0 || 1894 (options & (OBJPR_CLEANONLY | OBJPR_NOTMAPPED)) == OBJPR_NOTMAPPED, 1895 ("vm_object_page_remove: illegal options for object %p", object)); 1896 if (object->resident_page_count == 0) 1897 goto skipmemq; 1898 vm_object_pip_add(object, 1); 1899again: 1900 p = vm_page_find_least(object, start); 1901 1902 /* 1903 * Here, the variable "p" is either (1) the page with the least pindex 1904 * greater than or equal to the parameter "start" or (2) NULL. 1905 */ 1906 for (; p != NULL && (p->pindex < end || end == 0); p = next) { 1907 next = TAILQ_NEXT(p, listq); 1908 1909 /* 1910 * If the page is wired for any reason besides the existence 1911 * of managed, wired mappings, then it cannot be freed. For 1912 * example, fictitious pages, which represent device memory, 1913 * are inherently wired and cannot be freed. They can, 1914 * however, be invalidated if the option OBJPR_CLEANONLY is 1915 * not specified. 1916 */ 1917 vm_page_lock(p); 1918 if (vm_page_xbusied(p)) { 1919 VM_OBJECT_WUNLOCK(object); 1920 vm_page_busy_sleep(p, "vmopax"); 1921 VM_OBJECT_WLOCK(object); 1922 goto again; 1923 } 1924 if ((wirings = p->wire_count) != 0 && 1925 (wirings = pmap_page_wired_mappings(p)) != p->wire_count) { 1926 if ((options & (OBJPR_NOTWIRED | OBJPR_NOTMAPPED)) == 1927 0) { 1928 pmap_remove_all(p); 1929 /* Account for removal of wired mappings. */ 1930 if (wirings != 0) 1931 p->wire_count -= wirings; 1932 } 1933 if ((options & OBJPR_CLEANONLY) == 0) { 1934 p->valid = 0; 1935 vm_page_undirty(p); 1936 } 1937 goto next; 1938 } 1939 if (vm_page_busied(p)) { 1940 VM_OBJECT_WUNLOCK(object); 1941 vm_page_busy_sleep(p, "vmopar"); 1942 VM_OBJECT_WLOCK(object); 1943 goto again; 1944 } 1945 KASSERT((p->flags & PG_FICTITIOUS) == 0, 1946 ("vm_object_page_remove: page %p is fictitious", p)); 1947 if ((options & OBJPR_CLEANONLY) != 0 && p->valid != 0) { 1948 if ((options & OBJPR_NOTMAPPED) == 0) 1949 pmap_remove_write(p); 1950 if (p->dirty) 1951 goto next; 1952 } 1953 if ((options & OBJPR_NOTMAPPED) == 0) { 1954 if ((options & OBJPR_NOTWIRED) != 0 && wirings != 0) 1955 goto next; 1956 pmap_remove_all(p); 1957 /* Account for removal of wired mappings. */ 1958 if (wirings != 0) { 1959 KASSERT(p->wire_count == wirings, 1960 ("inconsistent wire count %d %d %p", 1961 p->wire_count, wirings, p)); 1962 p->wire_count = 0; 1963 atomic_subtract_int(&cnt.v_wire_count, 1); 1964 } 1965 } 1966 vm_page_free(p); 1967next: 1968 vm_page_unlock(p); 1969 } 1970 vm_object_pip_wakeup(object); 1971skipmemq: 1972 if (__predict_false(!vm_object_cache_is_empty(object))) 1973 vm_page_cache_free(object, start, end); 1974} 1975 1976/* 1977 * vm_object_page_cache: 1978 * 1979 * For the given object, attempt to move the specified clean 1980 * pages to the cache queue. If a page is wired for any reason, 1981 * then it will not be changed. Pages are specified by the given 1982 * range ["start", "end"). As a special case, if "end" is zero, 1983 * then the range extends from "start" to the end of the object. 1984 * Any mappings to the specified pages are removed before the 1985 * pages are moved to the cache queue. 1986 * 1987 * This operation should only be performed on objects that 1988 * contain non-fictitious, managed pages. 1989 * 1990 * The object must be locked. 1991 */ 1992void 1993vm_object_page_cache(vm_object_t object, vm_pindex_t start, vm_pindex_t end) 1994{ 1995 struct mtx *mtx, *new_mtx; 1996 vm_page_t p, next; 1997 1998 VM_OBJECT_ASSERT_WLOCKED(object); 1999 KASSERT((object->flags & (OBJ_FICTITIOUS | OBJ_UNMANAGED)) == 0, 2000 ("vm_object_page_cache: illegal object %p", object)); 2001 if (object->resident_page_count == 0) 2002 return; 2003 p = vm_page_find_least(object, start); 2004 2005 /* 2006 * Here, the variable "p" is either (1) the page with the least pindex 2007 * greater than or equal to the parameter "start" or (2) NULL. 2008 */ 2009 mtx = NULL; 2010 for (; p != NULL && (p->pindex < end || end == 0); p = next) { 2011 next = TAILQ_NEXT(p, listq); 2012 2013 /* 2014 * Avoid releasing and reacquiring the same page lock. 2015 */ 2016 new_mtx = vm_page_lockptr(p); 2017 if (mtx != new_mtx) { 2018 if (mtx != NULL) 2019 mtx_unlock(mtx); 2020 mtx = new_mtx; 2021 mtx_lock(mtx); 2022 } 2023 vm_page_try_to_cache(p); 2024 } 2025 if (mtx != NULL) 2026 mtx_unlock(mtx); 2027} 2028 2029/* 2030 * Populate the specified range of the object with valid pages. Returns 2031 * TRUE if the range is successfully populated and FALSE otherwise. 2032 * 2033 * Note: This function should be optimized to pass a larger array of 2034 * pages to vm_pager_get_pages() before it is applied to a non- 2035 * OBJT_DEVICE object. 2036 * 2037 * The object must be locked. 2038 */ 2039boolean_t 2040vm_object_populate(vm_object_t object, vm_pindex_t start, vm_pindex_t end) 2041{ 2042 vm_page_t m, ma[1]; 2043 vm_pindex_t pindex; 2044 int rv; 2045 2046 VM_OBJECT_ASSERT_WLOCKED(object); 2047 for (pindex = start; pindex < end; pindex++) { 2048 m = vm_page_grab(object, pindex, VM_ALLOC_NORMAL); 2049 if (m->valid != VM_PAGE_BITS_ALL) { 2050 ma[0] = m; 2051 rv = vm_pager_get_pages(object, ma, 1, 0); 2052 m = vm_page_lookup(object, pindex); 2053 if (m == NULL) 2054 break; 2055 if (rv != VM_PAGER_OK) { 2056 vm_page_lock(m); 2057 vm_page_free(m); 2058 vm_page_unlock(m); 2059 break; 2060 } 2061 } 2062 /* 2063 * Keep "m" busy because a subsequent iteration may unlock 2064 * the object. 2065 */ 2066 } 2067 if (pindex > start) { 2068 m = vm_page_lookup(object, start); 2069 while (m != NULL && m->pindex < pindex) { 2070 vm_page_xunbusy(m); 2071 m = TAILQ_NEXT(m, listq); 2072 } 2073 } 2074 return (pindex == end); 2075} 2076 2077/* 2078 * Routine: vm_object_coalesce 2079 * Function: Coalesces two objects backing up adjoining 2080 * regions of memory into a single object. 2081 * 2082 * returns TRUE if objects were combined. 2083 * 2084 * NOTE: Only works at the moment if the second object is NULL - 2085 * if it's not, which object do we lock first? 2086 * 2087 * Parameters: 2088 * prev_object First object to coalesce 2089 * prev_offset Offset into prev_object 2090 * prev_size Size of reference to prev_object 2091 * next_size Size of reference to the second object 2092 * reserved Indicator that extension region has 2093 * swap accounted for 2094 * 2095 * Conditions: 2096 * The object must *not* be locked. 2097 */ 2098boolean_t 2099vm_object_coalesce(vm_object_t prev_object, vm_ooffset_t prev_offset, 2100 vm_size_t prev_size, vm_size_t next_size, boolean_t reserved) 2101{ 2102 vm_pindex_t next_pindex; 2103 2104 if (prev_object == NULL) 2105 return (TRUE); 2106 VM_OBJECT_WLOCK(prev_object); 2107 if ((prev_object->type != OBJT_DEFAULT && 2108 prev_object->type != OBJT_SWAP) || 2109 (prev_object->flags & OBJ_TMPFS_NODE) != 0) { 2110 VM_OBJECT_WUNLOCK(prev_object); 2111 return (FALSE); 2112 } 2113 2114 /* 2115 * Try to collapse the object first 2116 */ 2117 vm_object_collapse(prev_object); 2118 2119 /* 2120 * Can't coalesce if: . more than one reference . paged out . shadows 2121 * another object . has a copy elsewhere (any of which mean that the 2122 * pages not mapped to prev_entry may be in use anyway) 2123 */ 2124 if (prev_object->backing_object != NULL) { 2125 VM_OBJECT_WUNLOCK(prev_object); 2126 return (FALSE); 2127 } 2128 2129 prev_size >>= PAGE_SHIFT; 2130 next_size >>= PAGE_SHIFT; 2131 next_pindex = OFF_TO_IDX(prev_offset) + prev_size; 2132 2133 if ((prev_object->ref_count > 1) && 2134 (prev_object->size != next_pindex)) { 2135 VM_OBJECT_WUNLOCK(prev_object); 2136 return (FALSE); 2137 } 2138 2139 /* 2140 * Account for the charge. 2141 */ 2142 if (prev_object->cred != NULL) { 2143 2144 /* 2145 * If prev_object was charged, then this mapping, 2146 * althought not charged now, may become writable 2147 * later. Non-NULL cred in the object would prevent 2148 * swap reservation during enabling of the write 2149 * access, so reserve swap now. Failed reservation 2150 * cause allocation of the separate object for the map 2151 * entry, and swap reservation for this entry is 2152 * managed in appropriate time. 2153 */ 2154 if (!reserved && !swap_reserve_by_cred(ptoa(next_size), 2155 prev_object->cred)) { 2156 return (FALSE); 2157 } 2158 prev_object->charge += ptoa(next_size); 2159 } 2160 2161 /* 2162 * Remove any pages that may still be in the object from a previous 2163 * deallocation. 2164 */ 2165 if (next_pindex < prev_object->size) { 2166 vm_object_page_remove(prev_object, next_pindex, next_pindex + 2167 next_size, 0); 2168 if (prev_object->type == OBJT_SWAP) 2169 swap_pager_freespace(prev_object, 2170 next_pindex, next_size); 2171#if 0 2172 if (prev_object->cred != NULL) { 2173 KASSERT(prev_object->charge >= 2174 ptoa(prev_object->size - next_pindex), 2175 ("object %p overcharged 1 %jx %jx", prev_object, 2176 (uintmax_t)next_pindex, (uintmax_t)next_size)); 2177 prev_object->charge -= ptoa(prev_object->size - 2178 next_pindex); 2179 } 2180#endif 2181 } 2182 2183 /* 2184 * Extend the object if necessary. 2185 */ 2186 if (next_pindex + next_size > prev_object->size) 2187 prev_object->size = next_pindex + next_size; 2188 2189 VM_OBJECT_WUNLOCK(prev_object); 2190 return (TRUE); 2191} 2192 2193void 2194vm_object_set_writeable_dirty(vm_object_t object) 2195{ 2196 2197 VM_OBJECT_ASSERT_WLOCKED(object); 2198 if (object->type != OBJT_VNODE) 2199 return; 2200 object->generation++; 2201 if ((object->flags & OBJ_MIGHTBEDIRTY) != 0) 2202 return; 2203 vm_object_set_flag(object, OBJ_MIGHTBEDIRTY); 2204} 2205 2206/* 2207 * vm_object_unwire: 2208 * 2209 * For each page offset within the specified range of the given object, 2210 * find the highest-level page in the shadow chain and unwire it. A page 2211 * must exist at every page offset, and the highest-level page must be 2212 * wired. 2213 */ 2214void 2215vm_object_unwire(vm_object_t object, vm_ooffset_t offset, vm_size_t length, 2216 uint8_t queue) 2217{ 2218 vm_object_t tobject; 2219 vm_page_t m, tm; 2220 vm_pindex_t end_pindex, pindex, tpindex; 2221 int depth, locked_depth; 2222 2223 KASSERT((offset & PAGE_MASK) == 0, 2224 ("vm_object_unwire: offset is not page aligned")); 2225 KASSERT((length & PAGE_MASK) == 0, 2226 ("vm_object_unwire: length is not a multiple of PAGE_SIZE")); 2227 /* The wired count of a fictitious page never changes. */ 2228 if ((object->flags & OBJ_FICTITIOUS) != 0) 2229 return; 2230 pindex = OFF_TO_IDX(offset); 2231 end_pindex = pindex + atop(length); 2232 locked_depth = 1; 2233 VM_OBJECT_RLOCK(object); 2234 m = vm_page_find_least(object, pindex); 2235 while (pindex < end_pindex) { 2236 if (m == NULL || pindex < m->pindex) { 2237 /* 2238 * The first object in the shadow chain doesn't 2239 * contain a page at the current index. Therefore, 2240 * the page must exist in a backing object. 2241 */ 2242 tobject = object; 2243 tpindex = pindex; 2244 depth = 0; 2245 do { 2246 tpindex += 2247 OFF_TO_IDX(tobject->backing_object_offset); 2248 tobject = tobject->backing_object; 2249 KASSERT(tobject != NULL, 2250 ("vm_object_unwire: missing page")); 2251 if ((tobject->flags & OBJ_FICTITIOUS) != 0) 2252 goto next_page; 2253 depth++; 2254 if (depth == locked_depth) { 2255 locked_depth++; 2256 VM_OBJECT_RLOCK(tobject); 2257 } 2258 } while ((tm = vm_page_lookup(tobject, tpindex)) == 2259 NULL); 2260 } else { 2261 tm = m; 2262 m = TAILQ_NEXT(m, listq); 2263 } 2264 vm_page_lock(tm); 2265 vm_page_unwire(tm, queue); 2266 vm_page_unlock(tm); 2267next_page: 2268 pindex++; 2269 } 2270 /* Release the accumulated object locks. */ 2271 for (depth = 0; depth < locked_depth; depth++) { 2272 tobject = object->backing_object; 2273 VM_OBJECT_RUNLOCK(object); 2274 object = tobject; 2275 } 2276} 2277 2278#include "opt_ddb.h" 2279#ifdef DDB 2280#include <sys/kernel.h> 2281 2282#include <sys/cons.h> 2283 2284#include <ddb/ddb.h> 2285 2286static int 2287_vm_object_in_map(vm_map_t map, vm_object_t object, vm_map_entry_t entry) 2288{ 2289 vm_map_t tmpm; 2290 vm_map_entry_t tmpe; 2291 vm_object_t obj; 2292 int entcount; 2293 2294 if (map == 0) 2295 return 0; 2296 2297 if (entry == 0) { 2298 tmpe = map->header.next; 2299 entcount = map->nentries; 2300 while (entcount-- && (tmpe != &map->header)) { 2301 if (_vm_object_in_map(map, object, tmpe)) { 2302 return 1; 2303 } 2304 tmpe = tmpe->next; 2305 } 2306 } else if (entry->eflags & MAP_ENTRY_IS_SUB_MAP) { 2307 tmpm = entry->object.sub_map; 2308 tmpe = tmpm->header.next; 2309 entcount = tmpm->nentries; 2310 while (entcount-- && tmpe != &tmpm->header) { 2311 if (_vm_object_in_map(tmpm, object, tmpe)) { 2312 return 1; 2313 } 2314 tmpe = tmpe->next; 2315 } 2316 } else if ((obj = entry->object.vm_object) != NULL) { 2317 for (; obj; obj = obj->backing_object) 2318 if (obj == object) { 2319 return 1; 2320 } 2321 } 2322 return 0; 2323} 2324 2325static int 2326vm_object_in_map(vm_object_t object) 2327{ 2328 struct proc *p; 2329 2330 /* sx_slock(&allproc_lock); */ 2331 FOREACH_PROC_IN_SYSTEM(p) { 2332 if (!p->p_vmspace /* || (p->p_flag & (P_SYSTEM|P_WEXIT)) */) 2333 continue; 2334 if (_vm_object_in_map(&p->p_vmspace->vm_map, object, 0)) { 2335 /* sx_sunlock(&allproc_lock); */ 2336 return 1; 2337 } 2338 } 2339 /* sx_sunlock(&allproc_lock); */ 2340 if (_vm_object_in_map(kernel_map, object, 0)) 2341 return 1; 2342 return 0; 2343} 2344 2345DB_SHOW_COMMAND(vmochk, vm_object_check) 2346{ 2347 vm_object_t object; 2348 2349 /* 2350 * make sure that internal objs are in a map somewhere 2351 * and none have zero ref counts. 2352 */ 2353 TAILQ_FOREACH(object, &vm_object_list, object_list) { 2354 if (object->handle == NULL && 2355 (object->type == OBJT_DEFAULT || object->type == OBJT_SWAP)) { 2356 if (object->ref_count == 0) { 2357 db_printf("vmochk: internal obj has zero ref count: %ld\n", 2358 (long)object->size); 2359 } 2360 if (!vm_object_in_map(object)) { 2361 db_printf( 2362 "vmochk: internal obj is not in a map: " 2363 "ref: %d, size: %lu: 0x%lx, backing_object: %p\n", 2364 object->ref_count, (u_long)object->size, 2365 (u_long)object->size, 2366 (void *)object->backing_object); 2367 } 2368 } 2369 } 2370} 2371 2372/* 2373 * vm_object_print: [ debug ] 2374 */ 2375DB_SHOW_COMMAND(object, vm_object_print_static) 2376{ 2377 /* XXX convert args. */ 2378 vm_object_t object = (vm_object_t)addr; 2379 boolean_t full = have_addr; 2380 2381 vm_page_t p; 2382 2383 /* XXX count is an (unused) arg. Avoid shadowing it. */ 2384#define count was_count 2385 2386 int count; 2387 2388 if (object == NULL) 2389 return; 2390 2391 db_iprintf( 2392 "Object %p: type=%d, size=0x%jx, res=%d, ref=%d, flags=0x%x ruid %d charge %jx\n", 2393 object, (int)object->type, (uintmax_t)object->size, 2394 object->resident_page_count, object->ref_count, object->flags, 2395 object->cred ? object->cred->cr_ruid : -1, (uintmax_t)object->charge); 2396 db_iprintf(" sref=%d, backing_object(%d)=(%p)+0x%jx\n", 2397 object->shadow_count, 2398 object->backing_object ? object->backing_object->ref_count : 0, 2399 object->backing_object, (uintmax_t)object->backing_object_offset); 2400 2401 if (!full) 2402 return; 2403 2404 db_indent += 2; 2405 count = 0; 2406 TAILQ_FOREACH(p, &object->memq, listq) { 2407 if (count == 0) 2408 db_iprintf("memory:="); 2409 else if (count == 6) { 2410 db_printf("\n"); 2411 db_iprintf(" ..."); 2412 count = 0; 2413 } else 2414 db_printf(","); 2415 count++; 2416 2417 db_printf("(off=0x%jx,page=0x%jx)", 2418 (uintmax_t)p->pindex, (uintmax_t)VM_PAGE_TO_PHYS(p)); 2419 } 2420 if (count != 0) 2421 db_printf("\n"); 2422 db_indent -= 2; 2423} 2424 2425/* XXX. */ 2426#undef count 2427 2428/* XXX need this non-static entry for calling from vm_map_print. */ 2429void 2430vm_object_print( 2431 /* db_expr_t */ long addr, 2432 boolean_t have_addr, 2433 /* db_expr_t */ long count, 2434 char *modif) 2435{ 2436 vm_object_print_static(addr, have_addr, count, modif); 2437} 2438 2439DB_SHOW_COMMAND(vmopag, vm_object_print_pages) 2440{ 2441 vm_object_t object; 2442 vm_pindex_t fidx; 2443 vm_paddr_t pa; 2444 vm_page_t m, prev_m; 2445 int rcount, nl, c; 2446 2447 nl = 0; 2448 TAILQ_FOREACH(object, &vm_object_list, object_list) { 2449 db_printf("new object: %p\n", (void *)object); 2450 if (nl > 18) { 2451 c = cngetc(); 2452 if (c != ' ') 2453 return; 2454 nl = 0; 2455 } 2456 nl++; 2457 rcount = 0; 2458 fidx = 0; 2459 pa = -1; 2460 TAILQ_FOREACH(m, &object->memq, listq) { 2461 if (m->pindex > 128) 2462 break; 2463 if ((prev_m = TAILQ_PREV(m, pglist, listq)) != NULL && 2464 prev_m->pindex + 1 != m->pindex) { 2465 if (rcount) { 2466 db_printf(" index(%ld)run(%d)pa(0x%lx)\n", 2467 (long)fidx, rcount, (long)pa); 2468 if (nl > 18) { 2469 c = cngetc(); 2470 if (c != ' ') 2471 return; 2472 nl = 0; 2473 } 2474 nl++; 2475 rcount = 0; 2476 } 2477 } 2478 if (rcount && 2479 (VM_PAGE_TO_PHYS(m) == pa + rcount * PAGE_SIZE)) { 2480 ++rcount; 2481 continue; 2482 } 2483 if (rcount) { 2484 db_printf(" index(%ld)run(%d)pa(0x%lx)\n", 2485 (long)fidx, rcount, (long)pa); 2486 if (nl > 18) { 2487 c = cngetc(); 2488 if (c != ' ') 2489 return; 2490 nl = 0; 2491 } 2492 nl++; 2493 } 2494 fidx = m->pindex; 2495 pa = VM_PAGE_TO_PHYS(m); 2496 rcount = 1; 2497 } 2498 if (rcount) { 2499 db_printf(" index(%ld)run(%d)pa(0x%lx)\n", 2500 (long)fidx, rcount, (long)pa); 2501 if (nl > 18) { 2502 c = cngetc(); 2503 if (c != ' ') 2504 return; 2505 nl = 0; 2506 } 2507 nl++; 2508 } 2509 } 2510} 2511#endif /* DDB */ 2512