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("$FreeBSD$"); 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> 100 101 static int old_msync; 102 SYSCTL_INT(_vm, OID_AUTO, old_msync, CTLFLAG_RW, &old_msync, 0, 103 "Use old (insecure) msync behavior"); 104 105 static 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); 108 static boolean_t vm_object_page_remove_write(vm_page_t p, int flags, 109 boolean_t *clearobjflags); 110 static void vm_object_qcollapse(vm_object_t object); 111 static 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 */ 138 139 struct object_q vm_object_list; 140 struct mtx vm_object_list_mtx; /* lock for object list and count */ 141 142 struct vm_object kernel_object_store; 143 struct vm_object kmem_object_store; 144 145 static SYSCTL_NODE(_vm_stats, OID_AUTO, object, CTLFLAG_RD, 0, 146 "VM object stats"); 147 148 static long object_collapses; 149 SYSCTL_LONG(_vm_stats_object, OID_AUTO, collapses, CTLFLAG_RD, 150 &object_collapses, 0, "VM object collapses"); 151 152 static long object_bypasses; 153 SYSCTL_LONG(_vm_stats_object, OID_AUTO, bypasses, CTLFLAG_RD, 154 &object_bypasses, 0, "VM object bypasses"); 155 156 static uma_zone_t obj_zone; 157 158 static int vm_object_zinit(void *mem, int size, int flags); 159 160 #ifdef INVARIANTS 161 static void vm_object_zdtor(void *mem, int size, void *arg); 162 163 static void 164 vm_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 192 193 static int 194 vm_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 } 212 213 static 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 */ 267 void 268 vm_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 } 304 305 void 306 vm_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 */ 322 int 323 vm_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 } 347 348 void 349 vm_object_pip_add(vm_object_t object, short i) 350 { 351 352 VM_OBJECT_ASSERT_WLOCKED(object); 353 object->paging_in_progress += i; 354 } 355 356 void 357 vm_object_pip_subtract(vm_object_t object, short i) 358 { 359 360 VM_OBJECT_ASSERT_WLOCKED(object); 361 object->paging_in_progress -= i; 362 } 363 364 void 365 vm_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 } 375 376 void 377 vm_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 } 388 389 void 390 vm_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 */ 405 vm_object_t 406 vm_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 */ 422 void 423 vm_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 */ 439 void 440 vm_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 */ 455 static void 456 vm_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 */ 506 void 507 vm_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++; 598 retry: 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 } 637 doterm: 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 */ 665 void 666 vm_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 ("%s: non-swap obj %p has cred", __func__, object)); 683 swap_release_by_cred(object->charge, object->cred); 684 object->charge = 0; 685 crfree(object->cred); 686 object->cred = NULL; 687 } 688 689 /* 690 * Free the space for the object. 691 */ 692 uma_zfree(obj_zone, object); 693 } 694 695 /* 696 * vm_object_terminate actually destroys the specified object, freeing 697 * up all previously used resources. 698 * 699 * The object must be locked. 700 * This routine may block. 701 */ 702 void 703 vm_object_terminate(vm_object_t object) 704 { 705 vm_page_t p, p_next; 706 707 VM_OBJECT_ASSERT_WLOCKED(object); 708 709 /* 710 * Make sure no one uses us. 711 */ 712 vm_object_set_flag(object, OBJ_DEAD); 713 714 /* 715 * wait for the pageout daemon to be done with the object 716 */ 717 vm_object_pip_wait(object, "objtrm"); 718 719 KASSERT(!object->paging_in_progress, 720 ("vm_object_terminate: pageout in progress")); 721 722 /* 723 * Clean and free the pages, as appropriate. All references to the 724 * object are gone, so we don't need to lock it. 725 */ 726 if (object->type == OBJT_VNODE) { 727 struct vnode *vp = (struct vnode *)object->handle; 728 729 /* 730 * Clean pages and flush buffers. 731 */ 732 vm_object_page_clean(object, 0, 0, OBJPC_SYNC); 733 VM_OBJECT_WUNLOCK(object); 734 735 vinvalbuf(vp, V_SAVE, 0, 0); 736 737 VM_OBJECT_WLOCK(object); 738 } 739 740 KASSERT(object->ref_count == 0, 741 ("vm_object_terminate: object with references, ref_count=%d", 742 object->ref_count)); 743 744 /* 745 * Free any remaining pageable pages. This also removes them from the 746 * paging queues. However, don't free wired pages, just remove them 747 * from the object. Rather than incrementally removing each page from 748 * the object, the page and object are reset to any empty state. 749 */ 750 TAILQ_FOREACH_SAFE(p, &object->memq, listq, p_next) { 751 vm_page_assert_unbusied(p); 752 vm_page_lock(p); 753 /* 754 * Optimize the page's removal from the object by resetting 755 * its "object" field. Specifically, if the page is not 756 * wired, then the effect of this assignment is that 757 * vm_page_free()'s call to vm_page_remove() will return 758 * immediately without modifying the page or the object. 759 */ 760 p->object = NULL; 761 if (p->wire_count == 0) { 762 vm_page_free(p); 763 PCPU_INC(cnt.v_pfree); 764 } 765 vm_page_unlock(p); 766 } 767 /* 768 * If the object contained any pages, then reset it to an empty state. 769 * None of the object's fields, including "resident_page_count", were 770 * modified by the preceding loop. 771 */ 772 if (object->resident_page_count != 0) { 773 vm_radix_reclaim_allnodes(&object->rtree); 774 TAILQ_INIT(&object->memq); 775 object->resident_page_count = 0; 776 if (object->type == OBJT_VNODE) 777 vdrop(object->handle); 778 } 779 780 #if VM_NRESERVLEVEL > 0 781 if (__predict_false(!LIST_EMPTY(&object->rvq))) 782 vm_reserv_break_all(object); 783 #endif 784 if (__predict_false(!vm_object_cache_is_empty(object))) 785 vm_page_cache_free(object, 0, 0); 786 787 /* 788 * Let the pager know object is dead. 789 */ 790 vm_pager_deallocate(object); 791 VM_OBJECT_WUNLOCK(object); 792 793 vm_object_destroy(object); 794 } 795 796 /* 797 * Make the page read-only so that we can clear the object flags. However, if 798 * this is a nosync mmap then the object is likely to stay dirty so do not 799 * mess with the page and do not clear the object flags. Returns TRUE if the 800 * page should be flushed, and FALSE otherwise. 801 */ 802 static boolean_t 803 vm_object_page_remove_write(vm_page_t p, int flags, boolean_t *clearobjflags) 804 { 805 806 /* 807 * If we have been asked to skip nosync pages and this is a 808 * nosync page, skip it. Note that the object flags were not 809 * cleared in this case so we do not have to set them. 810 */ 811 if ((flags & OBJPC_NOSYNC) != 0 && (p->oflags & VPO_NOSYNC) != 0) { 812 *clearobjflags = FALSE; 813 return (FALSE); 814 } else { 815 pmap_remove_write(p); 816 return (p->dirty != 0); 817 } 818 } 819 820 /* 821 * vm_object_page_clean 822 * 823 * Clean all dirty pages in the specified range of object. Leaves page 824 * on whatever queue it is currently on. If NOSYNC is set then do not 825 * write out pages with VPO_NOSYNC set (originally comes from MAP_NOSYNC), 826 * leaving the object dirty. 827 * 828 * When stuffing pages asynchronously, allow clustering. XXX we need a 829 * synchronous clustering mode implementation. 830 * 831 * Odd semantics: if start == end, we clean everything. 832 * 833 * The object must be locked. 834 * 835 * Returns FALSE if some page from the range was not written, as 836 * reported by the pager, and TRUE otherwise. 837 */ 838 boolean_t 839 vm_object_page_clean(vm_object_t object, vm_ooffset_t start, vm_ooffset_t end, 840 int flags) 841 { 842 vm_page_t np, p; 843 vm_pindex_t pi, tend, tstart; 844 int curgeneration, n, pagerflags; 845 boolean_t clearobjflags, eio, res; 846 847 VM_OBJECT_ASSERT_WLOCKED(object); 848 849 /* 850 * The OBJ_MIGHTBEDIRTY flag is only set for OBJT_VNODE 851 * objects. The check below prevents the function from 852 * operating on non-vnode objects. 853 */ 854 if ((object->flags & OBJ_MIGHTBEDIRTY) == 0 || 855 object->resident_page_count == 0) 856 return (TRUE); 857 858 pagerflags = (flags & (OBJPC_SYNC | OBJPC_INVAL)) != 0 ? 859 VM_PAGER_PUT_SYNC : VM_PAGER_CLUSTER_OK; 860 pagerflags |= (flags & OBJPC_INVAL) != 0 ? VM_PAGER_PUT_INVAL : 0; 861 862 tstart = OFF_TO_IDX(start); 863 tend = (end == 0) ? object->size : OFF_TO_IDX(end + PAGE_MASK); 864 clearobjflags = tstart == 0 && tend >= object->size; 865 res = TRUE; 866 867 rescan: 868 curgeneration = object->generation; 869 870 for (p = vm_page_find_least(object, tstart); p != NULL; p = np) { 871 pi = p->pindex; 872 if (pi >= tend) 873 break; 874 np = TAILQ_NEXT(p, listq); 875 if (p->valid == 0) 876 continue; 877 if (vm_page_sleep_if_busy(p, "vpcwai")) { 878 if (object->generation != curgeneration) { 879 if ((flags & OBJPC_SYNC) != 0) 880 goto rescan; 881 else 882 clearobjflags = FALSE; 883 } 884 np = vm_page_find_least(object, pi); 885 continue; 886 } 887 if (!vm_object_page_remove_write(p, flags, &clearobjflags)) 888 continue; 889 890 n = vm_object_page_collect_flush(object, p, pagerflags, 891 flags, &clearobjflags, &eio); 892 if (eio) { 893 res = FALSE; 894 clearobjflags = FALSE; 895 } 896 if (object->generation != curgeneration) { 897 if ((flags & OBJPC_SYNC) != 0) 898 goto rescan; 899 else 900 clearobjflags = FALSE; 901 } 902 903 /* 904 * If the VOP_PUTPAGES() did a truncated write, so 905 * that even the first page of the run is not fully 906 * written, vm_pageout_flush() returns 0 as the run 907 * length. Since the condition that caused truncated 908 * write may be permanent, e.g. exhausted free space, 909 * accepting n == 0 would cause an infinite loop. 910 * 911 * Forwarding the iterator leaves the unwritten page 912 * behind, but there is not much we can do there if 913 * filesystem refuses to write it. 914 */ 915 if (n == 0) { 916 n = 1; 917 clearobjflags = FALSE; 918 } 919 np = vm_page_find_least(object, pi + n); 920 } 921 #if 0 922 VOP_FSYNC(vp, (pagerflags & VM_PAGER_PUT_SYNC) ? MNT_WAIT : 0); 923 #endif 924 925 if (clearobjflags) 926 vm_object_clear_flag(object, OBJ_MIGHTBEDIRTY); 927 return (res); 928 } 929 930 static int 931 vm_object_page_collect_flush(vm_object_t object, vm_page_t p, int pagerflags, 932 int flags, boolean_t *clearobjflags, boolean_t *eio) 933 { 934 vm_page_t ma[vm_pageout_page_count], p_first, tp; 935 int count, i, mreq, runlen; 936 937 vm_page_lock_assert(p, MA_NOTOWNED); 938 VM_OBJECT_ASSERT_WLOCKED(object); 939 940 count = 1; 941 mreq = 0; 942 943 for (tp = p; count < vm_pageout_page_count; count++) { 944 tp = vm_page_next(tp); 945 if (tp == NULL || vm_page_busied(tp)) 946 break; 947 if (!vm_object_page_remove_write(tp, flags, clearobjflags)) 948 break; 949 } 950 951 for (p_first = p; count < vm_pageout_page_count; count++) { 952 tp = vm_page_prev(p_first); 953 if (tp == NULL || vm_page_busied(tp)) 954 break; 955 if (!vm_object_page_remove_write(tp, flags, clearobjflags)) 956 break; 957 p_first = tp; 958 mreq++; 959 } 960 961 for (tp = p_first, i = 0; i < count; tp = TAILQ_NEXT(tp, listq), i++) 962 ma[i] = tp; 963 964 vm_pageout_flush(ma, count, pagerflags, mreq, &runlen, eio); 965 return (runlen); 966 } 967 968 /* 969 * Note that there is absolutely no sense in writing out 970 * anonymous objects, so we track down the vnode object 971 * to write out. 972 * We invalidate (remove) all pages from the address space 973 * for semantic correctness. 974 * 975 * If the backing object is a device object with unmanaged pages, then any 976 * mappings to the specified range of pages must be removed before this 977 * function is called. 978 * 979 * Note: certain anonymous maps, such as MAP_NOSYNC maps, 980 * may start out with a NULL object. 981 */ 982 boolean_t 983 vm_object_sync(vm_object_t object, vm_ooffset_t offset, vm_size_t size, 984 boolean_t syncio, boolean_t invalidate) 985 { 986 vm_object_t backing_object; 987 struct vnode *vp; 988 struct mount *mp; 989 int error, flags, fsync_after; 990 boolean_t res; 991 992 if (object == NULL) 993 return (TRUE); 994 res = TRUE; 995 error = 0; 996 VM_OBJECT_WLOCK(object); 997 while ((backing_object = object->backing_object) != NULL) { 998 VM_OBJECT_WLOCK(backing_object); 999 offset += object->backing_object_offset; 1000 VM_OBJECT_WUNLOCK(object); 1001 object = backing_object; 1002 if (object->size < OFF_TO_IDX(offset + size)) 1003 size = IDX_TO_OFF(object->size) - offset; 1004 } 1005 /* 1006 * Flush pages if writing is allowed, invalidate them 1007 * if invalidation requested. Pages undergoing I/O 1008 * will be ignored by vm_object_page_remove(). 1009 * 1010 * We cannot lock the vnode and then wait for paging 1011 * to complete without deadlocking against vm_fault. 1012 * Instead we simply call vm_object_page_remove() and 1013 * allow it to block internally on a page-by-page 1014 * basis when it encounters pages undergoing async 1015 * I/O. 1016 */ 1017 if (object->type == OBJT_VNODE && 1018 (object->flags & OBJ_MIGHTBEDIRTY) != 0) { 1019 vp = object->handle; 1020 VM_OBJECT_WUNLOCK(object); 1021 (void) vn_start_write(vp, &mp, V_WAIT); 1022 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY); 1023 if (syncio && !invalidate && offset == 0 && 1024 OFF_TO_IDX(size) == object->size) { 1025 /* 1026 * If syncing the whole mapping of the file, 1027 * it is faster to schedule all the writes in 1028 * async mode, also allowing the clustering, 1029 * and then wait for i/o to complete. 1030 */ 1031 flags = 0; 1032 fsync_after = TRUE; 1033 } else { 1034 flags = (syncio || invalidate) ? OBJPC_SYNC : 0; 1035 flags |= invalidate ? (OBJPC_SYNC | OBJPC_INVAL) : 0; 1036 fsync_after = FALSE; 1037 } 1038 VM_OBJECT_WLOCK(object); 1039 res = vm_object_page_clean(object, offset, offset + size, 1040 flags); 1041 VM_OBJECT_WUNLOCK(object); 1042 if (fsync_after) 1043 error = VOP_FSYNC(vp, MNT_WAIT, curthread); 1044 VOP_UNLOCK(vp, 0); 1045 vn_finished_write(mp); 1046 if (error != 0) 1047 res = FALSE; 1048 VM_OBJECT_WLOCK(object); 1049 } 1050 if ((object->type == OBJT_VNODE || 1051 object->type == OBJT_DEVICE) && invalidate) { 1052 if (object->type == OBJT_DEVICE) 1053 /* 1054 * The option OBJPR_NOTMAPPED must be passed here 1055 * because vm_object_page_remove() cannot remove 1056 * unmanaged mappings. 1057 */ 1058 flags = OBJPR_NOTMAPPED; 1059 else if (old_msync) 1060 flags = OBJPR_NOTWIRED; 1061 else 1062 flags = OBJPR_CLEANONLY | OBJPR_NOTWIRED; 1063 vm_object_page_remove(object, OFF_TO_IDX(offset), 1064 OFF_TO_IDX(offset + size + PAGE_MASK), flags); 1065 } 1066 VM_OBJECT_WUNLOCK(object); 1067 return (res); 1068 } 1069 1070 /* 1071 * vm_object_madvise: 1072 * 1073 * Implements the madvise function at the object/page level. 1074 * 1075 * MADV_WILLNEED (any object) 1076 * 1077 * Activate the specified pages if they are resident. 1078 * 1079 * MADV_DONTNEED (any object) 1080 * 1081 * Deactivate the specified pages if they are resident. 1082 * 1083 * MADV_FREE (OBJT_DEFAULT/OBJT_SWAP objects, 1084 * OBJ_ONEMAPPING only) 1085 * 1086 * Deactivate and clean the specified pages if they are 1087 * resident. This permits the process to reuse the pages 1088 * without faulting or the kernel to reclaim the pages 1089 * without I/O. 1090 */ 1091 void 1092 vm_object_madvise(vm_object_t object, vm_pindex_t pindex, vm_pindex_t end, 1093 int advise) 1094 { 1095 vm_pindex_t tpindex; 1096 vm_object_t backing_object, tobject; 1097 vm_page_t m; 1098 1099 if (object == NULL) 1100 return; 1101 VM_OBJECT_WLOCK(object); 1102 /* 1103 * Locate and adjust resident pages 1104 */ 1105 for (; pindex < end; pindex += 1) { 1106 relookup: 1107 tobject = object; 1108 tpindex = pindex; 1109 shadowlookup: 1110 /* 1111 * MADV_FREE only operates on OBJT_DEFAULT or OBJT_SWAP pages 1112 * and those pages must be OBJ_ONEMAPPING. 1113 */ 1114 if (advise == MADV_FREE) { 1115 if ((tobject->type != OBJT_DEFAULT && 1116 tobject->type != OBJT_SWAP) || 1117 (tobject->flags & OBJ_ONEMAPPING) == 0) { 1118 goto unlock_tobject; 1119 } 1120 } else if ((tobject->flags & OBJ_UNMANAGED) != 0) 1121 goto unlock_tobject; 1122 m = vm_page_lookup(tobject, tpindex); 1123 if (m == NULL && advise == MADV_WILLNEED) { 1124 /* 1125 * If the page is cached, reactivate it. 1126 */ 1127 m = vm_page_alloc(tobject, tpindex, VM_ALLOC_IFCACHED | 1128 VM_ALLOC_NOBUSY); 1129 } 1130 if (m == NULL) { 1131 /* 1132 * There may be swap even if there is no backing page 1133 */ 1134 if (advise == MADV_FREE && tobject->type == OBJT_SWAP) 1135 swap_pager_freespace(tobject, tpindex, 1); 1136 /* 1137 * next object 1138 */ 1139 backing_object = tobject->backing_object; 1140 if (backing_object == NULL) 1141 goto unlock_tobject; 1142 VM_OBJECT_WLOCK(backing_object); 1143 tpindex += OFF_TO_IDX(tobject->backing_object_offset); 1144 if (tobject != object) 1145 VM_OBJECT_WUNLOCK(tobject); 1146 tobject = backing_object; 1147 goto shadowlookup; 1148 } else if (m->valid != VM_PAGE_BITS_ALL) 1149 goto unlock_tobject; 1150 /* 1151 * If the page is not in a normal state, skip it. 1152 */ 1153 vm_page_lock(m); 1154 if (m->hold_count != 0 || m->wire_count != 0) { 1155 vm_page_unlock(m); 1156 goto unlock_tobject; 1157 } 1158 KASSERT((m->flags & PG_FICTITIOUS) == 0, 1159 ("vm_object_madvise: page %p is fictitious", m)); 1160 KASSERT((m->oflags & VPO_UNMANAGED) == 0, 1161 ("vm_object_madvise: page %p is not managed", m)); 1162 if (vm_page_busied(m)) { 1163 if (advise == MADV_WILLNEED) { 1164 /* 1165 * Reference the page before unlocking and 1166 * sleeping so that the page daemon is less 1167 * likely to reclaim it. 1168 */ 1169 vm_page_aflag_set(m, PGA_REFERENCED); 1170 } 1171 if (object != tobject) 1172 VM_OBJECT_WUNLOCK(object); 1173 VM_OBJECT_WUNLOCK(tobject); 1174 vm_page_busy_sleep(m, "madvpo"); 1175 VM_OBJECT_WLOCK(object); 1176 goto relookup; 1177 } 1178 if (advise == MADV_WILLNEED) { 1179 vm_page_activate(m); 1180 } else { 1181 vm_page_advise(m, advise); 1182 } 1183 vm_page_unlock(m); 1184 if (advise == MADV_FREE && tobject->type == OBJT_SWAP) 1185 swap_pager_freespace(tobject, tpindex, 1); 1186 unlock_tobject: 1187 if (tobject != object) 1188 VM_OBJECT_WUNLOCK(tobject); 1189 } 1190 VM_OBJECT_WUNLOCK(object); 1191 } 1192 1193 /* 1194 * vm_object_shadow: 1195 * 1196 * Create a new object which is backed by the 1197 * specified existing object range. The source 1198 * object reference is deallocated. 1199 * 1200 * The new object and offset into that object 1201 * are returned in the source parameters. 1202 */ 1203 void 1204 vm_object_shadow( 1205 vm_object_t *object, /* IN/OUT */ 1206 vm_ooffset_t *offset, /* IN/OUT */ 1207 vm_size_t length) 1208 { 1209 vm_object_t source; 1210 vm_object_t result; 1211 1212 source = *object; 1213 1214 /* 1215 * Don't create the new object if the old object isn't shared. 1216 */ 1217 if (source != NULL) { 1218 VM_OBJECT_WLOCK(source); 1219 if (source->ref_count == 1 && 1220 source->handle == NULL && 1221 (source->type == OBJT_DEFAULT || 1222 source->type == OBJT_SWAP)) { 1223 VM_OBJECT_WUNLOCK(source); 1224 return; 1225 } 1226 VM_OBJECT_WUNLOCK(source); 1227 } 1228 1229 /* 1230 * Allocate a new object with the given length. 1231 */ 1232 result = vm_object_allocate(OBJT_DEFAULT, atop(length)); 1233 1234 /* 1235 * The new object shadows the source object, adding a reference to it. 1236 * Our caller changes his reference to point to the new object, 1237 * removing a reference to the source object. Net result: no change 1238 * of reference count. 1239 * 1240 * Try to optimize the result object's page color when shadowing 1241 * in order to maintain page coloring consistency in the combined 1242 * shadowed object. 1243 */ 1244 result->backing_object = source; 1245 /* 1246 * Store the offset into the source object, and fix up the offset into 1247 * the new object. 1248 */ 1249 result->backing_object_offset = *offset; 1250 if (source != NULL) { 1251 VM_OBJECT_WLOCK(source); 1252 LIST_INSERT_HEAD(&source->shadow_head, result, shadow_list); 1253 source->shadow_count++; 1254 #if VM_NRESERVLEVEL > 0 1255 result->flags |= source->flags & OBJ_COLORED; 1256 result->pg_color = (source->pg_color + OFF_TO_IDX(*offset)) & 1257 ((1 << (VM_NFREEORDER - 1)) - 1); 1258 #endif 1259 VM_OBJECT_WUNLOCK(source); 1260 } 1261 1262 1263 /* 1264 * Return the new things 1265 */ 1266 *offset = 0; 1267 *object = result; 1268 } 1269 1270 /* 1271 * vm_object_split: 1272 * 1273 * Split the pages in a map entry into a new object. This affords 1274 * easier removal of unused pages, and keeps object inheritance from 1275 * being a negative impact on memory usage. 1276 */ 1277 void 1278 vm_object_split(vm_map_entry_t entry) 1279 { 1280 vm_page_t m, m_next; 1281 vm_object_t orig_object, new_object, source; 1282 vm_pindex_t idx, offidxstart; 1283 vm_size_t size; 1284 1285 orig_object = entry->object.vm_object; 1286 if (orig_object->type != OBJT_DEFAULT && orig_object->type != OBJT_SWAP) 1287 return; 1288 if (orig_object->ref_count <= 1) 1289 return; 1290 VM_OBJECT_WUNLOCK(orig_object); 1291 1292 offidxstart = OFF_TO_IDX(entry->offset); 1293 size = atop(entry->end - entry->start); 1294 1295 /* 1296 * If swap_pager_copy() is later called, it will convert new_object 1297 * into a swap object. 1298 */ 1299 new_object = vm_object_allocate(OBJT_DEFAULT, size); 1300 1301 /* 1302 * At this point, the new object is still private, so the order in 1303 * which the original and new objects are locked does not matter. 1304 */ 1305 VM_OBJECT_WLOCK(new_object); 1306 VM_OBJECT_WLOCK(orig_object); 1307 source = orig_object->backing_object; 1308 if (source != NULL) { 1309 VM_OBJECT_WLOCK(source); 1310 if ((source->flags & OBJ_DEAD) != 0) { 1311 VM_OBJECT_WUNLOCK(source); 1312 VM_OBJECT_WUNLOCK(orig_object); 1313 VM_OBJECT_WUNLOCK(new_object); 1314 vm_object_deallocate(new_object); 1315 VM_OBJECT_WLOCK(orig_object); 1316 return; 1317 } 1318 LIST_INSERT_HEAD(&source->shadow_head, 1319 new_object, shadow_list); 1320 source->shadow_count++; 1321 vm_object_reference_locked(source); /* for new_object */ 1322 vm_object_clear_flag(source, OBJ_ONEMAPPING); 1323 VM_OBJECT_WUNLOCK(source); 1324 new_object->backing_object_offset = 1325 orig_object->backing_object_offset + entry->offset; 1326 new_object->backing_object = source; 1327 } 1328 if (orig_object->cred != NULL) { 1329 new_object->cred = orig_object->cred; 1330 crhold(orig_object->cred); 1331 new_object->charge = ptoa(size); 1332 KASSERT(orig_object->charge >= ptoa(size), 1333 ("orig_object->charge < 0")); 1334 orig_object->charge -= ptoa(size); 1335 } 1336 retry: 1337 m = vm_page_find_least(orig_object, offidxstart); 1338 for (; m != NULL && (idx = m->pindex - offidxstart) < size; 1339 m = m_next) { 1340 m_next = TAILQ_NEXT(m, listq); 1341 1342 /* 1343 * We must wait for pending I/O to complete before we can 1344 * rename the page. 1345 * 1346 * We do not have to VM_PROT_NONE the page as mappings should 1347 * not be changed by this operation. 1348 */ 1349 if (vm_page_busied(m)) { 1350 VM_OBJECT_WUNLOCK(new_object); 1351 vm_page_lock(m); 1352 VM_OBJECT_WUNLOCK(orig_object); 1353 vm_page_busy_sleep(m, "spltwt"); 1354 VM_OBJECT_WLOCK(orig_object); 1355 VM_OBJECT_WLOCK(new_object); 1356 goto retry; 1357 } 1358 1359 /* vm_page_rename() will handle dirty and cache. */ 1360 if (vm_page_rename(m, new_object, idx)) { 1361 VM_OBJECT_WUNLOCK(new_object); 1362 VM_OBJECT_WUNLOCK(orig_object); 1363 VM_WAIT; 1364 VM_OBJECT_WLOCK(orig_object); 1365 VM_OBJECT_WLOCK(new_object); 1366 goto retry; 1367 } 1368 #if VM_NRESERVLEVEL > 0 1369 /* 1370 * If some of the reservation's allocated pages remain with 1371 * the original object, then transferring the reservation to 1372 * the new object is neither particularly beneficial nor 1373 * particularly harmful as compared to leaving the reservation 1374 * with the original object. If, however, all of the 1375 * reservation's allocated pages are transferred to the new 1376 * object, then transferring the reservation is typically 1377 * beneficial. Determining which of these two cases applies 1378 * would be more costly than unconditionally renaming the 1379 * reservation. 1380 */ 1381 vm_reserv_rename(m, new_object, orig_object, offidxstart); 1382 #endif 1383 if (orig_object->type == OBJT_SWAP) 1384 vm_page_xbusy(m); 1385 } 1386 if (orig_object->type == OBJT_SWAP) { 1387 /* 1388 * swap_pager_copy() can sleep, in which case the orig_object's 1389 * and new_object's locks are released and reacquired. 1390 */ 1391 swap_pager_copy(orig_object, new_object, offidxstart, 0); 1392 TAILQ_FOREACH(m, &new_object->memq, listq) 1393 vm_page_xunbusy(m); 1394 1395 /* 1396 * Transfer any cached pages from orig_object to new_object. 1397 * If swap_pager_copy() found swapped out pages within the 1398 * specified range of orig_object, then it changed 1399 * new_object's type to OBJT_SWAP when it transferred those 1400 * pages to new_object. Otherwise, new_object's type 1401 * should still be OBJT_DEFAULT and orig_object should not 1402 * contain any cached pages within the specified range. 1403 */ 1404 if (__predict_false(!vm_object_cache_is_empty(orig_object))) 1405 vm_page_cache_transfer(orig_object, offidxstart, 1406 new_object); 1407 } 1408 VM_OBJECT_WUNLOCK(orig_object); 1409 VM_OBJECT_WUNLOCK(new_object); 1410 entry->object.vm_object = new_object; 1411 entry->offset = 0LL; 1412 vm_object_deallocate(orig_object); 1413 VM_OBJECT_WLOCK(new_object); 1414 } 1415 1416 #define OBSC_TEST_ALL_SHADOWED 0x0001 1417 #define OBSC_COLLAPSE_NOWAIT 0x0002 1418 #define OBSC_COLLAPSE_WAIT 0x0004 1419 1420 static int 1421 vm_object_backing_scan(vm_object_t object, int op) 1422 { 1423 int r = 1; 1424 vm_page_t p; 1425 vm_object_t backing_object; 1426 vm_pindex_t backing_offset_index; 1427 1428 VM_OBJECT_ASSERT_WLOCKED(object); 1429 VM_OBJECT_ASSERT_WLOCKED(object->backing_object); 1430 1431 backing_object = object->backing_object; 1432 backing_offset_index = OFF_TO_IDX(object->backing_object_offset); 1433 1434 /* 1435 * Initial conditions 1436 */ 1437 if (op & OBSC_TEST_ALL_SHADOWED) { 1438 /* 1439 * We do not want to have to test for the existence of cache 1440 * or swap pages in the backing object. XXX but with the 1441 * new swapper this would be pretty easy to do. 1442 * 1443 * XXX what about anonymous MAP_SHARED memory that hasn't 1444 * been ZFOD faulted yet? If we do not test for this, the 1445 * shadow test may succeed! XXX 1446 */ 1447 if (backing_object->type != OBJT_DEFAULT) { 1448 return (0); 1449 } 1450 } 1451 if (op & OBSC_COLLAPSE_WAIT) { 1452 vm_object_set_flag(backing_object, OBJ_DEAD); 1453 } 1454 1455 /* 1456 * Our scan 1457 */ 1458 p = TAILQ_FIRST(&backing_object->memq); 1459 while (p) { 1460 vm_page_t next = TAILQ_NEXT(p, listq); 1461 vm_pindex_t new_pindex = p->pindex - backing_offset_index; 1462 1463 if (op & OBSC_TEST_ALL_SHADOWED) { 1464 vm_page_t pp; 1465 1466 /* 1467 * Ignore pages outside the parent object's range 1468 * and outside the parent object's mapping of the 1469 * backing object. 1470 * 1471 * note that we do not busy the backing object's 1472 * page. 1473 */ 1474 if ( 1475 p->pindex < backing_offset_index || 1476 new_pindex >= object->size 1477 ) { 1478 p = next; 1479 continue; 1480 } 1481 1482 /* 1483 * See if the parent has the page or if the parent's 1484 * object pager has the page. If the parent has the 1485 * page but the page is not valid, the parent's 1486 * object pager must have the page. 1487 * 1488 * If this fails, the parent does not completely shadow 1489 * the object and we might as well give up now. 1490 */ 1491 1492 pp = vm_page_lookup(object, new_pindex); 1493 if ( 1494 (pp == NULL || pp->valid == 0) && 1495 !vm_pager_has_page(object, new_pindex, NULL, NULL) 1496 ) { 1497 r = 0; 1498 break; 1499 } 1500 } 1501 1502 /* 1503 * Check for busy page 1504 */ 1505 if (op & (OBSC_COLLAPSE_WAIT | OBSC_COLLAPSE_NOWAIT)) { 1506 vm_page_t pp; 1507 1508 if (op & OBSC_COLLAPSE_NOWAIT) { 1509 if (!p->valid || vm_page_busied(p)) { 1510 p = next; 1511 continue; 1512 } 1513 } else if (op & OBSC_COLLAPSE_WAIT) { 1514 if (vm_page_busied(p)) { 1515 VM_OBJECT_WUNLOCK(object); 1516 vm_page_lock(p); 1517 VM_OBJECT_WUNLOCK(backing_object); 1518 vm_page_busy_sleep(p, "vmocol"); 1519 VM_OBJECT_WLOCK(object); 1520 VM_OBJECT_WLOCK(backing_object); 1521 /* 1522 * If we slept, anything could have 1523 * happened. Since the object is 1524 * marked dead, the backing offset 1525 * should not have changed so we 1526 * just restart our scan. 1527 */ 1528 p = TAILQ_FIRST(&backing_object->memq); 1529 continue; 1530 } 1531 } 1532 1533 KASSERT( 1534 p->object == backing_object, 1535 ("vm_object_backing_scan: object mismatch") 1536 ); 1537 1538 if ( 1539 p->pindex < backing_offset_index || 1540 new_pindex >= object->size 1541 ) { 1542 if (backing_object->type == OBJT_SWAP) 1543 swap_pager_freespace(backing_object, 1544 p->pindex, 1); 1545 1546 /* 1547 * Page is out of the parent object's range, we 1548 * can simply destroy it. 1549 */ 1550 vm_page_lock(p); 1551 KASSERT(!pmap_page_is_mapped(p), 1552 ("freeing mapped page %p", p)); 1553 if (p->wire_count == 0) 1554 vm_page_free(p); 1555 else 1556 vm_page_remove(p); 1557 vm_page_unlock(p); 1558 p = next; 1559 continue; 1560 } 1561 1562 pp = vm_page_lookup(object, new_pindex); 1563 if ( 1564 (op & OBSC_COLLAPSE_NOWAIT) != 0 && 1565 (pp != NULL && pp->valid == 0) 1566 ) { 1567 if (backing_object->type == OBJT_SWAP) 1568 swap_pager_freespace(backing_object, 1569 p->pindex, 1); 1570 1571 /* 1572 * The page in the parent is not (yet) valid. 1573 * We don't know anything about the state of 1574 * the original page. It might be mapped, 1575 * so we must avoid the next if here. 1576 * 1577 * This is due to a race in vm_fault() where 1578 * we must unbusy the original (backing_obj) 1579 * page before we can (re)lock the parent. 1580 * Hence we can get here. 1581 */ 1582 p = next; 1583 continue; 1584 } 1585 if ( 1586 pp != NULL || 1587 vm_pager_has_page(object, new_pindex, NULL, NULL) 1588 ) { 1589 if (backing_object->type == OBJT_SWAP) 1590 swap_pager_freespace(backing_object, 1591 p->pindex, 1); 1592 1593 /* 1594 * page already exists in parent OR swap exists 1595 * for this location in the parent. Destroy 1596 * the original page from the backing object. 1597 * 1598 * Leave the parent's page alone 1599 */ 1600 vm_page_lock(p); 1601 KASSERT(!pmap_page_is_mapped(p), 1602 ("freeing mapped page %p", p)); 1603 if (p->wire_count == 0) 1604 vm_page_free(p); 1605 else 1606 vm_page_remove(p); 1607 vm_page_unlock(p); 1608 p = next; 1609 continue; 1610 } 1611 1612 /* 1613 * Page does not exist in parent, rename the 1614 * page from the backing object to the main object. 1615 * 1616 * If the page was mapped to a process, it can remain 1617 * mapped through the rename. 1618 * vm_page_rename() will handle dirty and cache. 1619 */ 1620 if (vm_page_rename(p, object, new_pindex)) { 1621 if (op & OBSC_COLLAPSE_NOWAIT) { 1622 p = next; 1623 continue; 1624 } 1625 VM_OBJECT_WLOCK(backing_object); 1626 VM_OBJECT_WUNLOCK(object); 1627 VM_WAIT; 1628 VM_OBJECT_WLOCK(object); 1629 VM_OBJECT_WLOCK(backing_object); 1630 p = TAILQ_FIRST(&backing_object->memq); 1631 continue; 1632 } 1633 1634 /* Use the old pindex to free the right page. */ 1635 if (backing_object->type == OBJT_SWAP) 1636 swap_pager_freespace(backing_object, 1637 new_pindex + backing_offset_index, 1); 1638 1639 #if VM_NRESERVLEVEL > 0 1640 /* 1641 * Rename the reservation. 1642 */ 1643 vm_reserv_rename(p, object, backing_object, 1644 backing_offset_index); 1645 #endif 1646 } 1647 p = next; 1648 } 1649 return (r); 1650 } 1651 1652 1653 /* 1654 * this version of collapse allows the operation to occur earlier and 1655 * when paging_in_progress is true for an object... This is not a complete 1656 * operation, but should plug 99.9% of the rest of the leaks. 1657 */ 1658 static void 1659 vm_object_qcollapse(vm_object_t object) 1660 { 1661 vm_object_t backing_object = object->backing_object; 1662 1663 VM_OBJECT_ASSERT_WLOCKED(object); 1664 VM_OBJECT_ASSERT_WLOCKED(backing_object); 1665 1666 if (backing_object->ref_count != 1) 1667 return; 1668 1669 vm_object_backing_scan(object, OBSC_COLLAPSE_NOWAIT); 1670 } 1671 1672 /* 1673 * vm_object_collapse: 1674 * 1675 * Collapse an object with the object backing it. 1676 * Pages in the backing object are moved into the 1677 * parent, and the backing object is deallocated. 1678 */ 1679 void 1680 vm_object_collapse(vm_object_t object) 1681 { 1682 VM_OBJECT_ASSERT_WLOCKED(object); 1683 1684 while (TRUE) { 1685 vm_object_t backing_object; 1686 1687 /* 1688 * Verify that the conditions are right for collapse: 1689 * 1690 * The object exists and the backing object exists. 1691 */ 1692 if ((backing_object = object->backing_object) == NULL) 1693 break; 1694 1695 /* 1696 * we check the backing object first, because it is most likely 1697 * not collapsable. 1698 */ 1699 VM_OBJECT_WLOCK(backing_object); 1700 if (backing_object->handle != NULL || 1701 (backing_object->type != OBJT_DEFAULT && 1702 backing_object->type != OBJT_SWAP) || 1703 (backing_object->flags & OBJ_DEAD) || 1704 object->handle != NULL || 1705 (object->type != OBJT_DEFAULT && 1706 object->type != OBJT_SWAP) || 1707 (object->flags & OBJ_DEAD)) { 1708 VM_OBJECT_WUNLOCK(backing_object); 1709 break; 1710 } 1711 1712 if ( 1713 object->paging_in_progress != 0 || 1714 backing_object->paging_in_progress != 0 1715 ) { 1716 vm_object_qcollapse(object); 1717 VM_OBJECT_WUNLOCK(backing_object); 1718 break; 1719 } 1720 /* 1721 * We know that we can either collapse the backing object (if 1722 * the parent is the only reference to it) or (perhaps) have 1723 * the parent bypass the object if the parent happens to shadow 1724 * all the resident pages in the entire backing object. 1725 * 1726 * This is ignoring pager-backed pages such as swap pages. 1727 * vm_object_backing_scan fails the shadowing test in this 1728 * case. 1729 */ 1730 if (backing_object->ref_count == 1) { 1731 /* 1732 * If there is exactly one reference to the backing 1733 * object, we can collapse it into the parent. 1734 */ 1735 vm_object_backing_scan(object, OBSC_COLLAPSE_WAIT); 1736 1737 #if VM_NRESERVLEVEL > 0 1738 /* 1739 * Break any reservations from backing_object. 1740 */ 1741 if (__predict_false(!LIST_EMPTY(&backing_object->rvq))) 1742 vm_reserv_break_all(backing_object); 1743 #endif 1744 1745 /* 1746 * Move the pager from backing_object to object. 1747 */ 1748 if (backing_object->type == OBJT_SWAP) { 1749 /* 1750 * swap_pager_copy() can sleep, in which case 1751 * the backing_object's and object's locks are 1752 * released and reacquired. 1753 * Since swap_pager_copy() is being asked to 1754 * destroy the source, it will change the 1755 * backing_object's type to OBJT_DEFAULT. 1756 */ 1757 swap_pager_copy( 1758 backing_object, 1759 object, 1760 OFF_TO_IDX(object->backing_object_offset), TRUE); 1761 1762 /* 1763 * Free any cached pages from backing_object. 1764 */ 1765 if (__predict_false( 1766 !vm_object_cache_is_empty(backing_object))) 1767 vm_page_cache_free(backing_object, 0, 0); 1768 } 1769 /* 1770 * Object now shadows whatever backing_object did. 1771 * Note that the reference to 1772 * backing_object->backing_object moves from within 1773 * backing_object to within object. 1774 */ 1775 LIST_REMOVE(object, shadow_list); 1776 backing_object->shadow_count--; 1777 if (backing_object->backing_object) { 1778 VM_OBJECT_WLOCK(backing_object->backing_object); 1779 LIST_REMOVE(backing_object, shadow_list); 1780 LIST_INSERT_HEAD( 1781 &backing_object->backing_object->shadow_head, 1782 object, shadow_list); 1783 /* 1784 * The shadow_count has not changed. 1785 */ 1786 VM_OBJECT_WUNLOCK(backing_object->backing_object); 1787 } 1788 object->backing_object = backing_object->backing_object; 1789 object->backing_object_offset += 1790 backing_object->backing_object_offset; 1791 1792 /* 1793 * Discard backing_object. 1794 * 1795 * Since the backing object has no pages, no pager left, 1796 * and no object references within it, all that is 1797 * necessary is to dispose of it. 1798 */ 1799 KASSERT(backing_object->ref_count == 1, ( 1800 "backing_object %p was somehow re-referenced during collapse!", 1801 backing_object)); 1802 VM_OBJECT_WUNLOCK(backing_object); 1803 vm_object_destroy(backing_object); 1804 1805 object_collapses++; 1806 } else { 1807 vm_object_t new_backing_object; 1808 1809 /* 1810 * If we do not entirely shadow the backing object, 1811 * there is nothing we can do so we give up. 1812 */ 1813 if (object->resident_page_count != object->size && 1814 vm_object_backing_scan(object, 1815 OBSC_TEST_ALL_SHADOWED) == 0) { 1816 VM_OBJECT_WUNLOCK(backing_object); 1817 break; 1818 } 1819 1820 /* 1821 * Make the parent shadow the next object in the 1822 * chain. Deallocating backing_object will not remove 1823 * it, since its reference count is at least 2. 1824 */ 1825 LIST_REMOVE(object, shadow_list); 1826 backing_object->shadow_count--; 1827 1828 new_backing_object = backing_object->backing_object; 1829 if ((object->backing_object = new_backing_object) != NULL) { 1830 VM_OBJECT_WLOCK(new_backing_object); 1831 LIST_INSERT_HEAD( 1832 &new_backing_object->shadow_head, 1833 object, 1834 shadow_list 1835 ); 1836 new_backing_object->shadow_count++; 1837 vm_object_reference_locked(new_backing_object); 1838 VM_OBJECT_WUNLOCK(new_backing_object); 1839 object->backing_object_offset += 1840 backing_object->backing_object_offset; 1841 } 1842 1843 /* 1844 * Drop the reference count on backing_object. Since 1845 * its ref_count was at least 2, it will not vanish. 1846 */ 1847 backing_object->ref_count--; 1848 VM_OBJECT_WUNLOCK(backing_object); 1849 object_bypasses++; 1850 } 1851 1852 /* 1853 * Try again with this object's new backing object. 1854 */ 1855 } 1856 } 1857 1858 /* 1859 * vm_object_page_remove: 1860 * 1861 * For the given object, either frees or invalidates each of the 1862 * specified pages. In general, a page is freed. However, if a page is 1863 * wired for any reason other than the existence of a managed, wired 1864 * mapping, then it may be invalidated but not removed from the object. 1865 * Pages are specified by the given range ["start", "end") and the option 1866 * OBJPR_CLEANONLY. As a special case, if "end" is zero, then the range 1867 * extends from "start" to the end of the object. If the option 1868 * OBJPR_CLEANONLY is specified, then only the non-dirty pages within the 1869 * specified range are affected. If the option OBJPR_NOTMAPPED is 1870 * specified, then the pages within the specified range must have no 1871 * mappings. Otherwise, if this option is not specified, any mappings to 1872 * the specified pages are removed before the pages are freed or 1873 * invalidated. 1874 * 1875 * In general, this operation should only be performed on objects that 1876 * contain managed pages. There are, however, two exceptions. First, it 1877 * is performed on the kernel and kmem objects by vm_map_entry_delete(). 1878 * Second, it is used by msync(..., MS_INVALIDATE) to invalidate device- 1879 * backed pages. In both of these cases, the option OBJPR_CLEANONLY must 1880 * not be specified and the option OBJPR_NOTMAPPED must be specified. 1881 * 1882 * The object must be locked. 1883 */ 1884 void 1885 vm_object_page_remove(vm_object_t object, vm_pindex_t start, vm_pindex_t end, 1886 int options) 1887 { 1888 vm_page_t p, next; 1889 int wirings; 1890 1891 VM_OBJECT_ASSERT_WLOCKED(object); 1892 KASSERT((object->flags & OBJ_UNMANAGED) == 0 || 1893 (options & (OBJPR_CLEANONLY | OBJPR_NOTMAPPED)) == OBJPR_NOTMAPPED, 1894 ("vm_object_page_remove: illegal options for object %p", object)); 1895 if (object->resident_page_count == 0) 1896 goto skipmemq; 1897 vm_object_pip_add(object, 1); 1898 again: 1899 p = vm_page_find_least(object, start); 1900 1901 /* 1902 * Here, the variable "p" is either (1) the page with the least pindex 1903 * greater than or equal to the parameter "start" or (2) NULL. 1904 */ 1905 for (; p != NULL && (p->pindex < end || end == 0); p = next) { 1906 next = TAILQ_NEXT(p, listq); 1907 1908 /* 1909 * If the page is wired for any reason besides the existence 1910 * of managed, wired mappings, then it cannot be freed. For 1911 * example, fictitious pages, which represent device memory, 1912 * are inherently wired and cannot be freed. They can, 1913 * however, be invalidated if the option OBJPR_CLEANONLY is 1914 * not specified. 1915 */ 1916 vm_page_lock(p); 1917 if (vm_page_xbusied(p)) { 1918 VM_OBJECT_WUNLOCK(object); 1919 vm_page_busy_sleep(p, "vmopax"); 1920 VM_OBJECT_WLOCK(object); 1921 goto again; 1922 } 1923 if ((wirings = p->wire_count) != 0 && 1924 (wirings = pmap_page_wired_mappings(p)) != p->wire_count) { 1925 if ((options & (OBJPR_NOTWIRED | OBJPR_NOTMAPPED)) == 1926 0) { 1927 pmap_remove_all(p); 1928 /* Account for removal of wired mappings. */ 1929 if (wirings != 0) 1930 p->wire_count -= wirings; 1931 } 1932 if ((options & OBJPR_CLEANONLY) == 0) { 1933 p->valid = 0; 1934 vm_page_undirty(p); 1935 } 1936 goto next; 1937 } 1938 if (vm_page_busied(p)) { 1939 VM_OBJECT_WUNLOCK(object); 1940 vm_page_busy_sleep(p, "vmopar"); 1941 VM_OBJECT_WLOCK(object); 1942 goto again; 1943 } 1944 KASSERT((p->flags & PG_FICTITIOUS) == 0, 1945 ("vm_object_page_remove: page %p is fictitious", p)); 1946 if ((options & OBJPR_CLEANONLY) != 0 && p->valid != 0) { 1947 if ((options & OBJPR_NOTMAPPED) == 0) 1948 pmap_remove_write(p); 1949 if (p->dirty) 1950 goto next; 1951 } 1952 if ((options & OBJPR_NOTMAPPED) == 0) { 1953 if ((options & OBJPR_NOTWIRED) != 0 && wirings != 0) 1954 goto next; 1955 pmap_remove_all(p); 1956 /* Account for removal of wired mappings. */ 1957 if (wirings != 0) { 1958 KASSERT(p->wire_count == wirings, 1959 ("inconsistent wire count %d %d %p", 1960 p->wire_count, wirings, p)); 1961 p->wire_count = 0; 1962 atomic_subtract_int(&vm_cnt.v_wire_count, 1); 1963 } 1964 } 1965 vm_page_free(p); 1966 next: 1967 vm_page_unlock(p); 1968 } 1969 vm_object_pip_wakeup(object); 1970 skipmemq: 1971 if (__predict_false(!vm_object_cache_is_empty(object))) 1972 vm_page_cache_free(object, start, end); 1973 } 1974 1975 /* 1976 * vm_object_page_cache: 1977 * 1978 * For the given object, attempt to move the specified clean 1979 * pages to the cache queue. If a page is wired for any reason, 1980 * then it will not be changed. Pages are specified by the given 1981 * range ["start", "end"). As a special case, if "end" is zero, 1982 * then the range extends from "start" to the end of the object. 1983 * Any mappings to the specified pages are removed before the 1984 * pages are moved to the cache queue. 1985 * 1986 * This operation should only be performed on objects that 1987 * contain non-fictitious, managed pages. 1988 * 1989 * The object must be locked. 1990 */ 1991 void 1992 vm_object_page_cache(vm_object_t object, vm_pindex_t start, vm_pindex_t end) 1993 { 1994 struct mtx *mtx, *new_mtx; 1995 vm_page_t p, next; 1996 1997 VM_OBJECT_ASSERT_WLOCKED(object); 1998 KASSERT((object->flags & (OBJ_FICTITIOUS | OBJ_UNMANAGED)) == 0, 1999 ("vm_object_page_cache: illegal object %p", object)); 2000 if (object->resident_page_count == 0) 2001 return; 2002 p = vm_page_find_least(object, start); 2003 2004 /* 2005 * Here, the variable "p" is either (1) the page with the least pindex 2006 * greater than or equal to the parameter "start" or (2) NULL. 2007 */ 2008 mtx = NULL; 2009 for (; p != NULL && (p->pindex < end || end == 0); p = next) { 2010 next = TAILQ_NEXT(p, listq); 2011 2012 /* 2013 * Avoid releasing and reacquiring the same page lock. 2014 */ 2015 new_mtx = vm_page_lockptr(p); 2016 if (mtx != new_mtx) { 2017 if (mtx != NULL) 2018 mtx_unlock(mtx); 2019 mtx = new_mtx; 2020 mtx_lock(mtx); 2021 } 2022 vm_page_try_to_cache(p); 2023 } 2024 if (mtx != NULL) 2025 mtx_unlock(mtx); 2026 } 2027 2028 /* 2029 * Populate the specified range of the object with valid pages. Returns 2030 * TRUE if the range is successfully populated and FALSE otherwise. 2031 * 2032 * Note: This function should be optimized to pass a larger array of 2033 * pages to vm_pager_get_pages() before it is applied to a non- 2034 * OBJT_DEVICE object. 2035 * 2036 * The object must be locked. 2037 */ 2038 boolean_t 2039 vm_object_populate(vm_object_t object, vm_pindex_t start, vm_pindex_t end) 2040 { 2041 vm_page_t m, ma[1]; 2042 vm_pindex_t pindex; 2043 int rv; 2044 2045 VM_OBJECT_ASSERT_WLOCKED(object); 2046 for (pindex = start; pindex < end; pindex++) { 2047 m = vm_page_grab(object, pindex, VM_ALLOC_NORMAL); 2048 if (m->valid != VM_PAGE_BITS_ALL) { 2049 ma[0] = m; 2050 rv = vm_pager_get_pages(object, ma, 1, 0); 2051 m = vm_page_lookup(object, pindex); 2052 if (m == NULL) 2053 break; 2054 if (rv != VM_PAGER_OK) { 2055 vm_page_lock(m); 2056 vm_page_free(m); 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_xunbusy(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 */ 2097 boolean_t 2098 vm_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_WLOCK(prev_object); 2106 if ((prev_object->type != OBJT_DEFAULT && 2107 prev_object->type != OBJT_SWAP) || 2108 (prev_object->flags & OBJ_TMPFS_NODE) != 0) { 2109 VM_OBJECT_WUNLOCK(prev_object); 2110 return (FALSE); 2111 } 2112 2113 /* 2114 * Try to collapse the object first 2115 */ 2116 vm_object_collapse(prev_object); 2117 2118 /* 2119 * Can't coalesce if: . more than one reference . paged out . shadows 2120 * another object . has a copy elsewhere (any of which mean that the 2121 * pages not mapped to prev_entry may be in use anyway) 2122 */ 2123 if (prev_object->backing_object != NULL) { 2124 VM_OBJECT_WUNLOCK(prev_object); 2125 return (FALSE); 2126 } 2127 2128 prev_size >>= PAGE_SHIFT; 2129 next_size >>= PAGE_SHIFT; 2130 next_pindex = OFF_TO_IDX(prev_offset) + prev_size; 2131 2132 if ((prev_object->ref_count > 1) && 2133 (prev_object->size != next_pindex)) { 2134 VM_OBJECT_WUNLOCK(prev_object); 2135 return (FALSE); 2136 } 2137 2138 /* 2139 * Account for the charge. 2140 */ 2141 if (prev_object->cred != NULL) { 2142 2143 /* 2144 * If prev_object was charged, then this mapping, 2145 * althought not charged now, may become writable 2146 * later. Non-NULL cred in the object would prevent 2147 * swap reservation during enabling of the write 2148 * access, so reserve swap now. Failed reservation 2149 * cause allocation of the separate object for the map 2150 * entry, and swap reservation for this entry is 2151 * managed in appropriate time. 2152 */ 2153 if (!reserved && !swap_reserve_by_cred(ptoa(next_size), 2154 prev_object->cred)) { 2155 return (FALSE); 2156 } 2157 prev_object->charge += ptoa(next_size); 2158 } 2159 2160 /* 2161 * Remove any pages that may still be in the object from a previous 2162 * deallocation. 2163 */ 2164 if (next_pindex < prev_object->size) { 2165 vm_object_page_remove(prev_object, next_pindex, next_pindex + 2166 next_size, 0); 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->cred != 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_WUNLOCK(prev_object); 2189 return (TRUE); 2190 } 2191 2192 void 2193 vm_object_set_writeable_dirty(vm_object_t object) 2194 { 2195 2196 VM_OBJECT_ASSERT_WLOCKED(object); 2197 if (object->type != OBJT_VNODE) 2198 return; 2199 object->generation++; 2200 if ((object->flags & OBJ_MIGHTBEDIRTY) != 0) 2201 return; 2202 vm_object_set_flag(object, OBJ_MIGHTBEDIRTY); 2203 } 2204 2205 /* 2206 * vm_object_unwire: 2207 * 2208 * For each page offset within the specified range of the given object, 2209 * find the highest-level page in the shadow chain and unwire it. A page 2210 * must exist at every page offset, and the highest-level page must be 2211 * wired. 2212 */ 2213 void 2214 vm_object_unwire(vm_object_t object, vm_ooffset_t offset, vm_size_t length, 2215 uint8_t queue) 2216 { 2217 vm_object_t tobject; 2218 vm_page_t m, tm; 2219 vm_pindex_t end_pindex, pindex, tpindex; 2220 int depth, locked_depth; 2221 2222 KASSERT((offset & PAGE_MASK) == 0, 2223 ("vm_object_unwire: offset is not page aligned")); 2224 KASSERT((length & PAGE_MASK) == 0, 2225 ("vm_object_unwire: length is not a multiple of PAGE_SIZE")); 2226 /* The wired count of a fictitious page never changes. */ 2227 if ((object->flags & OBJ_FICTITIOUS) != 0) 2228 return; 2229 pindex = OFF_TO_IDX(offset); 2230 end_pindex = pindex + atop(length); 2231 locked_depth = 1; 2232 VM_OBJECT_RLOCK(object); 2233 m = vm_page_find_least(object, pindex); 2234 while (pindex < end_pindex) { 2235 if (m == NULL || pindex < m->pindex) { 2236 /* 2237 * The first object in the shadow chain doesn't 2238 * contain a page at the current index. Therefore, 2239 * the page must exist in a backing object. 2240 */ 2241 tobject = object; 2242 tpindex = pindex; 2243 depth = 0; 2244 do { 2245 tpindex += 2246 OFF_TO_IDX(tobject->backing_object_offset); 2247 tobject = tobject->backing_object; 2248 KASSERT(tobject != NULL, 2249 ("vm_object_unwire: missing page")); 2250 if ((tobject->flags & OBJ_FICTITIOUS) != 0) 2251 goto next_page; 2252 depth++; 2253 if (depth == locked_depth) { 2254 locked_depth++; 2255 VM_OBJECT_RLOCK(tobject); 2256 } 2257 } while ((tm = vm_page_lookup(tobject, tpindex)) == 2258 NULL); 2259 } else { 2260 tm = m; 2261 m = TAILQ_NEXT(m, listq); 2262 } 2263 vm_page_lock(tm); 2264 vm_page_unwire(tm, queue); 2265 vm_page_unlock(tm); 2266 next_page: 2267 pindex++; 2268 } 2269 /* Release the accumulated object locks. */ 2270 for (depth = 0; depth < locked_depth; depth++) { 2271 tobject = object->backing_object; 2272 VM_OBJECT_RUNLOCK(object); 2273 object = tobject; 2274 } 2275 } 2276 2277 #include "opt_ddb.h" 2278 #ifdef DDB 2279 #include <sys/kernel.h> 2280 2281 #include <sys/cons.h> 2282 2283 #include <ddb/ddb.h> 2284 2285 static int 2286 _vm_object_in_map(vm_map_t map, vm_object_t object, vm_map_entry_t entry) 2287 { 2288 vm_map_t tmpm; 2289 vm_map_entry_t tmpe; 2290 vm_object_t obj; 2291 int entcount; 2292 2293 if (map == 0) 2294 return 0; 2295 2296 if (entry == 0) { 2297 tmpe = map->header.next; 2298 entcount = map->nentries; 2299 while (entcount-- && (tmpe != &map->header)) { 2300 if (_vm_object_in_map(map, object, tmpe)) { 2301 return 1; 2302 } 2303 tmpe = tmpe->next; 2304 } 2305 } else if (entry->eflags & MAP_ENTRY_IS_SUB_MAP) { 2306 tmpm = entry->object.sub_map; 2307 tmpe = tmpm->header.next; 2308 entcount = tmpm->nentries; 2309 while (entcount-- && tmpe != &tmpm->header) { 2310 if (_vm_object_in_map(tmpm, object, tmpe)) { 2311 return 1; 2312 } 2313 tmpe = tmpe->next; 2314 } 2315 } else if ((obj = entry->object.vm_object) != NULL) { 2316 for (; obj; obj = obj->backing_object) 2317 if (obj == object) { 2318 return 1; 2319 } 2320 } 2321 return 0; 2322 } 2323 2324 static int 2325 vm_object_in_map(vm_object_t object) 2326 { 2327 struct proc *p; 2328 2329 /* sx_slock(&allproc_lock); */ 2330 FOREACH_PROC_IN_SYSTEM(p) { 2331 if (!p->p_vmspace /* || (p->p_flag & (P_SYSTEM|P_WEXIT)) */) 2332 continue; 2333 if (_vm_object_in_map(&p->p_vmspace->vm_map, object, 0)) { 2334 /* sx_sunlock(&allproc_lock); */ 2335 return 1; 2336 } 2337 } 2338 /* sx_sunlock(&allproc_lock); */ 2339 if (_vm_object_in_map(kernel_map, object, 0)) 2340 return 1; 2341 return 0; 2342 } 2343 2344 DB_SHOW_COMMAND(vmochk, vm_object_check) 2345 { 2346 vm_object_t object; 2347 2348 /* 2349 * make sure that internal objs are in a map somewhere 2350 * and none have zero ref counts. 2351 */ 2352 TAILQ_FOREACH(object, &vm_object_list, object_list) { 2353 if (object->handle == NULL && 2354 (object->type == OBJT_DEFAULT || object->type == OBJT_SWAP)) { 2355 if (object->ref_count == 0) { 2356 db_printf("vmochk: internal obj has zero ref count: %ld\n", 2357 (long)object->size); 2358 } 2359 if (!vm_object_in_map(object)) { 2360 db_printf( 2361 "vmochk: internal obj is not in a map: " 2362 "ref: %d, size: %lu: 0x%lx, backing_object: %p\n", 2363 object->ref_count, (u_long)object->size, 2364 (u_long)object->size, 2365 (void *)object->backing_object); 2366 } 2367 } 2368 } 2369 } 2370 2371 /* 2372 * vm_object_print: [ debug ] 2373 */ 2374 DB_SHOW_COMMAND(object, vm_object_print_static) 2375 { 2376 /* XXX convert args. */ 2377 vm_object_t object = (vm_object_t)addr; 2378 boolean_t full = have_addr; 2379 2380 vm_page_t p; 2381 2382 /* XXX count is an (unused) arg. Avoid shadowing it. */ 2383 #define count was_count 2384 2385 int count; 2386 2387 if (object == NULL) 2388 return; 2389 2390 db_iprintf( 2391 "Object %p: type=%d, size=0x%jx, res=%d, ref=%d, flags=0x%x ruid %d charge %jx\n", 2392 object, (int)object->type, (uintmax_t)object->size, 2393 object->resident_page_count, object->ref_count, object->flags, 2394 object->cred ? object->cred->cr_ruid : -1, (uintmax_t)object->charge); 2395 db_iprintf(" sref=%d, backing_object(%d)=(%p)+0x%jx\n", 2396 object->shadow_count, 2397 object->backing_object ? object->backing_object->ref_count : 0, 2398 object->backing_object, (uintmax_t)object->backing_object_offset); 2399 2400 if (!full) 2401 return; 2402 2403 db_indent += 2; 2404 count = 0; 2405 TAILQ_FOREACH(p, &object->memq, listq) { 2406 if (count == 0) 2407 db_iprintf("memory:="); 2408 else if (count == 6) { 2409 db_printf("\n"); 2410 db_iprintf(" ..."); 2411 count = 0; 2412 } else 2413 db_printf(","); 2414 count++; 2415 2416 db_printf("(off=0x%jx,page=0x%jx)", 2417 (uintmax_t)p->pindex, (uintmax_t)VM_PAGE_TO_PHYS(p)); 2418 } 2419 if (count != 0) 2420 db_printf("\n"); 2421 db_indent -= 2; 2422 } 2423 2424 /* XXX. */ 2425 #undef count 2426 2427 /* XXX need this non-static entry for calling from vm_map_print. */ 2428 void 2429 vm_object_print( 2430 /* db_expr_t */ long addr, 2431 boolean_t have_addr, 2432 /* db_expr_t */ long count, 2433 char *modif) 2434 { 2435 vm_object_print_static(addr, have_addr, count, modif); 2436 } 2437 2438 DB_SHOW_COMMAND(vmopag, vm_object_print_pages) 2439 { 2440 vm_object_t object; 2441 vm_pindex_t fidx; 2442 vm_paddr_t pa; 2443 vm_page_t m, prev_m; 2444 int rcount, nl, c; 2445 2446 nl = 0; 2447 TAILQ_FOREACH(object, &vm_object_list, object_list) { 2448 db_printf("new object: %p\n", (void *)object); 2449 if (nl > 18) { 2450 c = cngetc(); 2451 if (c != ' ') 2452 return; 2453 nl = 0; 2454 } 2455 nl++; 2456 rcount = 0; 2457 fidx = 0; 2458 pa = -1; 2459 TAILQ_FOREACH(m, &object->memq, listq) { 2460 if (m->pindex > 128) 2461 break; 2462 if ((prev_m = TAILQ_PREV(m, pglist, listq)) != NULL && 2463 prev_m->pindex + 1 != m->pindex) { 2464 if (rcount) { 2465 db_printf(" index(%ld)run(%d)pa(0x%lx)\n", 2466 (long)fidx, rcount, (long)pa); 2467 if (nl > 18) { 2468 c = cngetc(); 2469 if (c != ' ') 2470 return; 2471 nl = 0; 2472 } 2473 nl++; 2474 rcount = 0; 2475 } 2476 } 2477 if (rcount && 2478 (VM_PAGE_TO_PHYS(m) == pa + rcount * PAGE_SIZE)) { 2479 ++rcount; 2480 continue; 2481 } 2482 if (rcount) { 2483 db_printf(" index(%ld)run(%d)pa(0x%lx)\n", 2484 (long)fidx, rcount, (long)pa); 2485 if (nl > 18) { 2486 c = cngetc(); 2487 if (c != ' ') 2488 return; 2489 nl = 0; 2490 } 2491 nl++; 2492 } 2493 fidx = m->pindex; 2494 pa = VM_PAGE_TO_PHYS(m); 2495 rcount = 1; 2496 } 2497 if (rcount) { 2498 db_printf(" index(%ld)run(%d)pa(0x%lx)\n", 2499 (long)fidx, rcount, (long)pa); 2500 if (nl > 18) { 2501 c = cngetc(); 2502 if (c != ' ') 2503 return; 2504 nl = 0; 2505 } 2506 nl++; 2507 } 2508 } 2509 } 2510 #endif /* DDB */ 2511