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