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) == 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 KASSERT((object->flags & OBJ_TMPFS) == 0, 563 ("shadowed tmpfs v_object %p", object)); 564 vm_object_t robject; 565 566 robject = LIST_FIRST(&object->shadow_head); 567 KASSERT(robject != NULL, 568 ("vm_object_deallocate: ref_count: %d, shadow_count: %d", 569 object->ref_count, 570 object->shadow_count)); 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 VM_OBJECT_WLOCK(temp); 641 LIST_REMOVE(object, shadow_list); 642 temp->shadow_count--; 643 VM_OBJECT_WUNLOCK(temp); 644 object->backing_object = NULL; 645 } 646 /* 647 * Don't double-terminate, we could be in a termination 648 * recursion due to the terminate having to sync data 649 * to disk. 650 */ 651 if ((object->flags & OBJ_DEAD) == 0) 652 vm_object_terminate(object); 653 else 654 VM_OBJECT_WUNLOCK(object); 655 object = temp; 656 } 657 } 658 659 /* 660 * vm_object_destroy removes the object from the global object list 661 * and frees the space for the object. 662 */ 663 void 664 vm_object_destroy(vm_object_t object) 665 { 666 667 /* 668 * Remove the object from the global object list. 669 */ 670 mtx_lock(&vm_object_list_mtx); 671 TAILQ_REMOVE(&vm_object_list, object, object_list); 672 mtx_unlock(&vm_object_list_mtx); 673 674 /* 675 * Release the allocation charge. 676 */ 677 if (object->cred != NULL) { 678 KASSERT(object->type == OBJT_DEFAULT || 679 object->type == OBJT_SWAP, 680 ("%s: non-swap obj %p has cred", __func__, object)); 681 swap_release_by_cred(object->charge, object->cred); 682 object->charge = 0; 683 crfree(object->cred); 684 object->cred = NULL; 685 } 686 687 /* 688 * Free the space for the object. 689 */ 690 uma_zfree(obj_zone, object); 691 } 692 693 /* 694 * vm_object_terminate actually destroys the specified object, freeing 695 * up all previously used resources. 696 * 697 * The object must be locked. 698 * This routine may block. 699 */ 700 void 701 vm_object_terminate(vm_object_t object) 702 { 703 vm_page_t p, p_next; 704 705 VM_OBJECT_ASSERT_WLOCKED(object); 706 707 /* 708 * Make sure no one uses us. 709 */ 710 vm_object_set_flag(object, OBJ_DEAD); 711 712 /* 713 * wait for the pageout daemon to be done with the object 714 */ 715 vm_object_pip_wait(object, "objtrm"); 716 717 KASSERT(!object->paging_in_progress, 718 ("vm_object_terminate: pageout in progress")); 719 720 /* 721 * Clean and free the pages, as appropriate. All references to the 722 * object are gone, so we don't need to lock it. 723 */ 724 if (object->type == OBJT_VNODE) { 725 struct vnode *vp = (struct vnode *)object->handle; 726 727 /* 728 * Clean pages and flush buffers. 729 */ 730 vm_object_page_clean(object, 0, 0, OBJPC_SYNC); 731 VM_OBJECT_WUNLOCK(object); 732 733 vinvalbuf(vp, V_SAVE, 0, 0); 734 735 VM_OBJECT_WLOCK(object); 736 } 737 738 KASSERT(object->ref_count == 0, 739 ("vm_object_terminate: object with references, ref_count=%d", 740 object->ref_count)); 741 742 /* 743 * Free any remaining pageable pages. This also removes them from the 744 * paging queues. However, don't free wired pages, just remove them 745 * from the object. Rather than incrementally removing each page from 746 * the object, the page and object are reset to any empty state. 747 */ 748 TAILQ_FOREACH_SAFE(p, &object->memq, listq, p_next) { 749 vm_page_assert_unbusied(p); 750 vm_page_lock(p); 751 /* 752 * Optimize the page's removal from the object by resetting 753 * its "object" field. Specifically, if the page is not 754 * wired, then the effect of this assignment is that 755 * vm_page_free()'s call to vm_page_remove() will return 756 * immediately without modifying the page or the object. 757 */ 758 p->object = NULL; 759 if (p->wire_count == 0) { 760 vm_page_free(p); 761 PCPU_INC(cnt.v_pfree); 762 } 763 vm_page_unlock(p); 764 } 765 /* 766 * If the object contained any pages, then reset it to an empty state. 767 * None of the object's fields, including "resident_page_count", were 768 * modified by the preceding loop. 769 */ 770 if (object->resident_page_count != 0) { 771 vm_radix_reclaim_allnodes(&object->rtree); 772 TAILQ_INIT(&object->memq); 773 object->resident_page_count = 0; 774 if (object->type == OBJT_VNODE) 775 vdrop(object->handle); 776 } 777 778 #if VM_NRESERVLEVEL > 0 779 if (__predict_false(!LIST_EMPTY(&object->rvq))) 780 vm_reserv_break_all(object); 781 #endif 782 if (__predict_false(!vm_object_cache_is_empty(object))) 783 vm_page_cache_free(object, 0, 0); 784 785 /* 786 * Let the pager know object is dead. 787 */ 788 vm_pager_deallocate(object); 789 VM_OBJECT_WUNLOCK(object); 790 791 vm_object_destroy(object); 792 } 793 794 /* 795 * Make the page read-only so that we can clear the object flags. However, if 796 * this is a nosync mmap then the object is likely to stay dirty so do not 797 * mess with the page and do not clear the object flags. Returns TRUE if the 798 * page should be flushed, and FALSE otherwise. 799 */ 800 static boolean_t 801 vm_object_page_remove_write(vm_page_t p, int flags, boolean_t *clearobjflags) 802 { 803 804 /* 805 * If we have been asked to skip nosync pages and this is a 806 * nosync page, skip it. Note that the object flags were not 807 * cleared in this case so we do not have to set them. 808 */ 809 if ((flags & OBJPC_NOSYNC) != 0 && (p->oflags & VPO_NOSYNC) != 0) { 810 *clearobjflags = FALSE; 811 return (FALSE); 812 } else { 813 pmap_remove_write(p); 814 return (p->dirty != 0); 815 } 816 } 817 818 /* 819 * vm_object_page_clean 820 * 821 * Clean all dirty pages in the specified range of object. Leaves page 822 * on whatever queue it is currently on. If NOSYNC is set then do not 823 * write out pages with VPO_NOSYNC set (originally comes from MAP_NOSYNC), 824 * leaving the object dirty. 825 * 826 * When stuffing pages asynchronously, allow clustering. XXX we need a 827 * synchronous clustering mode implementation. 828 * 829 * Odd semantics: if start == end, we clean everything. 830 * 831 * The object must be locked. 832 * 833 * Returns FALSE if some page from the range was not written, as 834 * reported by the pager, and TRUE otherwise. 835 */ 836 boolean_t 837 vm_object_page_clean(vm_object_t object, vm_ooffset_t start, vm_ooffset_t end, 838 int flags) 839 { 840 vm_page_t np, p; 841 vm_pindex_t pi, tend, tstart; 842 int curgeneration, n, pagerflags; 843 boolean_t clearobjflags, eio, res; 844 845 VM_OBJECT_ASSERT_WLOCKED(object); 846 847 /* 848 * The OBJ_MIGHTBEDIRTY flag is only set for OBJT_VNODE 849 * objects. The check below prevents the function from 850 * operating on non-vnode objects. 851 */ 852 if ((object->flags & OBJ_MIGHTBEDIRTY) == 0 || 853 object->resident_page_count == 0) 854 return (TRUE); 855 856 pagerflags = (flags & (OBJPC_SYNC | OBJPC_INVAL)) != 0 ? 857 VM_PAGER_PUT_SYNC : VM_PAGER_CLUSTER_OK; 858 pagerflags |= (flags & OBJPC_INVAL) != 0 ? VM_PAGER_PUT_INVAL : 0; 859 860 tstart = OFF_TO_IDX(start); 861 tend = (end == 0) ? object->size : OFF_TO_IDX(end + PAGE_MASK); 862 clearobjflags = tstart == 0 && tend >= object->size; 863 res = TRUE; 864 865 rescan: 866 curgeneration = object->generation; 867 868 for (p = vm_page_find_least(object, tstart); p != NULL; p = np) { 869 pi = p->pindex; 870 if (pi >= tend) 871 break; 872 np = TAILQ_NEXT(p, listq); 873 if (p->valid == 0) 874 continue; 875 if (vm_page_sleep_if_busy(p, "vpcwai")) { 876 if (object->generation != curgeneration) { 877 if ((flags & OBJPC_SYNC) != 0) 878 goto rescan; 879 else 880 clearobjflags = FALSE; 881 } 882 np = vm_page_find_least(object, pi); 883 continue; 884 } 885 if (!vm_object_page_remove_write(p, flags, &clearobjflags)) 886 continue; 887 888 n = vm_object_page_collect_flush(object, p, pagerflags, 889 flags, &clearobjflags, &eio); 890 if (eio) { 891 res = FALSE; 892 clearobjflags = FALSE; 893 } 894 if (object->generation != curgeneration) { 895 if ((flags & OBJPC_SYNC) != 0) 896 goto rescan; 897 else 898 clearobjflags = FALSE; 899 } 900 901 /* 902 * If the VOP_PUTPAGES() did a truncated write, so 903 * that even the first page of the run is not fully 904 * written, vm_pageout_flush() returns 0 as the run 905 * length. Since the condition that caused truncated 906 * write may be permanent, e.g. exhausted free space, 907 * accepting n == 0 would cause an infinite loop. 908 * 909 * Forwarding the iterator leaves the unwritten page 910 * behind, but there is not much we can do there if 911 * filesystem refuses to write it. 912 */ 913 if (n == 0) { 914 n = 1; 915 clearobjflags = FALSE; 916 } 917 np = vm_page_find_least(object, pi + n); 918 } 919 #if 0 920 VOP_FSYNC(vp, (pagerflags & VM_PAGER_PUT_SYNC) ? MNT_WAIT : 0); 921 #endif 922 923 if (clearobjflags) 924 vm_object_clear_flag(object, OBJ_MIGHTBEDIRTY); 925 return (res); 926 } 927 928 static int 929 vm_object_page_collect_flush(vm_object_t object, vm_page_t p, int pagerflags, 930 int flags, boolean_t *clearobjflags, boolean_t *eio) 931 { 932 vm_page_t ma[vm_pageout_page_count], p_first, tp; 933 int count, i, mreq, runlen; 934 935 vm_page_lock_assert(p, MA_NOTOWNED); 936 VM_OBJECT_ASSERT_WLOCKED(object); 937 938 count = 1; 939 mreq = 0; 940 941 for (tp = p; count < vm_pageout_page_count; count++) { 942 tp = vm_page_next(tp); 943 if (tp == NULL || vm_page_busied(tp)) 944 break; 945 if (!vm_object_page_remove_write(tp, flags, clearobjflags)) 946 break; 947 } 948 949 for (p_first = p; count < vm_pageout_page_count; count++) { 950 tp = vm_page_prev(p_first); 951 if (tp == NULL || vm_page_busied(tp)) 952 break; 953 if (!vm_object_page_remove_write(tp, flags, clearobjflags)) 954 break; 955 p_first = tp; 956 mreq++; 957 } 958 959 for (tp = p_first, i = 0; i < count; tp = TAILQ_NEXT(tp, listq), i++) 960 ma[i] = tp; 961 962 vm_pageout_flush(ma, count, pagerflags, mreq, &runlen, eio); 963 return (runlen); 964 } 965 966 /* 967 * Note that there is absolutely no sense in writing out 968 * anonymous objects, so we track down the vnode object 969 * to write out. 970 * We invalidate (remove) all pages from the address space 971 * for semantic correctness. 972 * 973 * If the backing object is a device object with unmanaged pages, then any 974 * mappings to the specified range of pages must be removed before this 975 * function is called. 976 * 977 * Note: certain anonymous maps, such as MAP_NOSYNC maps, 978 * may start out with a NULL object. 979 */ 980 boolean_t 981 vm_object_sync(vm_object_t object, vm_ooffset_t offset, vm_size_t size, 982 boolean_t syncio, boolean_t invalidate) 983 { 984 vm_object_t backing_object; 985 struct vnode *vp; 986 struct mount *mp; 987 int error, flags, fsync_after; 988 boolean_t res; 989 990 if (object == NULL) 991 return (TRUE); 992 res = TRUE; 993 error = 0; 994 VM_OBJECT_WLOCK(object); 995 while ((backing_object = object->backing_object) != NULL) { 996 VM_OBJECT_WLOCK(backing_object); 997 offset += object->backing_object_offset; 998 VM_OBJECT_WUNLOCK(object); 999 object = backing_object; 1000 if (object->size < OFF_TO_IDX(offset + size)) 1001 size = IDX_TO_OFF(object->size) - offset; 1002 } 1003 /* 1004 * Flush pages if writing is allowed, invalidate them 1005 * if invalidation requested. Pages undergoing I/O 1006 * will be ignored by vm_object_page_remove(). 1007 * 1008 * We cannot lock the vnode and then wait for paging 1009 * to complete without deadlocking against vm_fault. 1010 * Instead we simply call vm_object_page_remove() and 1011 * allow it to block internally on a page-by-page 1012 * basis when it encounters pages undergoing async 1013 * I/O. 1014 */ 1015 if (object->type == OBJT_VNODE && 1016 (object->flags & OBJ_MIGHTBEDIRTY) != 0) { 1017 vp = object->handle; 1018 VM_OBJECT_WUNLOCK(object); 1019 (void) vn_start_write(vp, &mp, V_WAIT); 1020 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY); 1021 if (syncio && !invalidate && offset == 0 && 1022 OFF_TO_IDX(size) == object->size) { 1023 /* 1024 * If syncing the whole mapping of the file, 1025 * it is faster to schedule all the writes in 1026 * async mode, also allowing the clustering, 1027 * and then wait for i/o to complete. 1028 */ 1029 flags = 0; 1030 fsync_after = TRUE; 1031 } else { 1032 flags = (syncio || invalidate) ? OBJPC_SYNC : 0; 1033 flags |= invalidate ? (OBJPC_SYNC | OBJPC_INVAL) : 0; 1034 fsync_after = FALSE; 1035 } 1036 VM_OBJECT_WLOCK(object); 1037 res = vm_object_page_clean(object, offset, offset + size, 1038 flags); 1039 VM_OBJECT_WUNLOCK(object); 1040 if (fsync_after) 1041 error = VOP_FSYNC(vp, MNT_WAIT, curthread); 1042 VOP_UNLOCK(vp, 0); 1043 vn_finished_write(mp); 1044 if (error != 0) 1045 res = FALSE; 1046 VM_OBJECT_WLOCK(object); 1047 } 1048 if ((object->type == OBJT_VNODE || 1049 object->type == OBJT_DEVICE) && invalidate) { 1050 if (object->type == OBJT_DEVICE) 1051 /* 1052 * The option OBJPR_NOTMAPPED must be passed here 1053 * because vm_object_page_remove() cannot remove 1054 * unmanaged mappings. 1055 */ 1056 flags = OBJPR_NOTMAPPED; 1057 else if (old_msync) 1058 flags = OBJPR_NOTWIRED; 1059 else 1060 flags = OBJPR_CLEANONLY | OBJPR_NOTWIRED; 1061 vm_object_page_remove(object, OFF_TO_IDX(offset), 1062 OFF_TO_IDX(offset + size + PAGE_MASK), flags); 1063 } 1064 VM_OBJECT_WUNLOCK(object); 1065 return (res); 1066 } 1067 1068 /* 1069 * vm_object_madvise: 1070 * 1071 * Implements the madvise function at the object/page level. 1072 * 1073 * MADV_WILLNEED (any object) 1074 * 1075 * Activate the specified pages if they are resident. 1076 * 1077 * MADV_DONTNEED (any object) 1078 * 1079 * Deactivate the specified pages if they are resident. 1080 * 1081 * MADV_FREE (OBJT_DEFAULT/OBJT_SWAP objects, 1082 * OBJ_ONEMAPPING only) 1083 * 1084 * Deactivate and clean the specified pages if they are 1085 * resident. This permits the process to reuse the pages 1086 * without faulting or the kernel to reclaim the pages 1087 * without I/O. 1088 */ 1089 void 1090 vm_object_madvise(vm_object_t object, vm_pindex_t pindex, vm_pindex_t end, 1091 int advise) 1092 { 1093 vm_pindex_t tpindex; 1094 vm_object_t backing_object, tobject; 1095 vm_page_t m; 1096 1097 if (object == NULL) 1098 return; 1099 VM_OBJECT_WLOCK(object); 1100 /* 1101 * Locate and adjust resident pages 1102 */ 1103 for (; pindex < end; pindex += 1) { 1104 relookup: 1105 tobject = object; 1106 tpindex = pindex; 1107 shadowlookup: 1108 /* 1109 * MADV_FREE only operates on OBJT_DEFAULT or OBJT_SWAP pages 1110 * and those pages must be OBJ_ONEMAPPING. 1111 */ 1112 if (advise == MADV_FREE) { 1113 if ((tobject->type != OBJT_DEFAULT && 1114 tobject->type != OBJT_SWAP) || 1115 (tobject->flags & OBJ_ONEMAPPING) == 0) { 1116 goto unlock_tobject; 1117 } 1118 } else if ((tobject->flags & OBJ_UNMANAGED) != 0) 1119 goto unlock_tobject; 1120 m = vm_page_lookup(tobject, tpindex); 1121 if (m == NULL && advise == MADV_WILLNEED) { 1122 /* 1123 * If the page is cached, reactivate it. 1124 */ 1125 m = vm_page_alloc(tobject, tpindex, VM_ALLOC_IFCACHED | 1126 VM_ALLOC_NOBUSY); 1127 } 1128 if (m == NULL) { 1129 /* 1130 * There may be swap even if there is no backing page 1131 */ 1132 if (advise == MADV_FREE && tobject->type == OBJT_SWAP) 1133 swap_pager_freespace(tobject, tpindex, 1); 1134 /* 1135 * next object 1136 */ 1137 backing_object = tobject->backing_object; 1138 if (backing_object == NULL) 1139 goto unlock_tobject; 1140 VM_OBJECT_WLOCK(backing_object); 1141 tpindex += OFF_TO_IDX(tobject->backing_object_offset); 1142 if (tobject != object) 1143 VM_OBJECT_WUNLOCK(tobject); 1144 tobject = backing_object; 1145 goto shadowlookup; 1146 } else if (m->valid != VM_PAGE_BITS_ALL) 1147 goto unlock_tobject; 1148 /* 1149 * If the page is not in a normal state, skip it. 1150 */ 1151 vm_page_lock(m); 1152 if (m->hold_count != 0 || m->wire_count != 0) { 1153 vm_page_unlock(m); 1154 goto unlock_tobject; 1155 } 1156 KASSERT((m->flags & PG_FICTITIOUS) == 0, 1157 ("vm_object_madvise: page %p is fictitious", m)); 1158 KASSERT((m->oflags & VPO_UNMANAGED) == 0, 1159 ("vm_object_madvise: page %p is not managed", m)); 1160 if (vm_page_busied(m)) { 1161 if (advise == MADV_WILLNEED) { 1162 /* 1163 * Reference the page before unlocking and 1164 * sleeping so that the page daemon is less 1165 * likely to reclaim it. 1166 */ 1167 vm_page_aflag_set(m, PGA_REFERENCED); 1168 } 1169 if (object != tobject) 1170 VM_OBJECT_WUNLOCK(object); 1171 VM_OBJECT_WUNLOCK(tobject); 1172 vm_page_busy_sleep(m, "madvpo"); 1173 VM_OBJECT_WLOCK(object); 1174 goto relookup; 1175 } 1176 if (advise == MADV_WILLNEED) { 1177 vm_page_activate(m); 1178 } else { 1179 vm_page_advise(m, advise); 1180 } 1181 vm_page_unlock(m); 1182 if (advise == MADV_FREE && tobject->type == OBJT_SWAP) 1183 swap_pager_freespace(tobject, tpindex, 1); 1184 unlock_tobject: 1185 if (tobject != object) 1186 VM_OBJECT_WUNLOCK(tobject); 1187 } 1188 VM_OBJECT_WUNLOCK(object); 1189 } 1190 1191 /* 1192 * vm_object_shadow: 1193 * 1194 * Create a new object which is backed by the 1195 * specified existing object range. The source 1196 * object reference is deallocated. 1197 * 1198 * The new object and offset into that object 1199 * are returned in the source parameters. 1200 */ 1201 void 1202 vm_object_shadow( 1203 vm_object_t *object, /* IN/OUT */ 1204 vm_ooffset_t *offset, /* IN/OUT */ 1205 vm_size_t length) 1206 { 1207 vm_object_t source; 1208 vm_object_t result; 1209 1210 source = *object; 1211 1212 /* 1213 * Don't create the new object if the old object isn't shared. 1214 */ 1215 if (source != NULL) { 1216 VM_OBJECT_WLOCK(source); 1217 if (source->ref_count == 1 && 1218 source->handle == NULL && 1219 (source->type == OBJT_DEFAULT || 1220 source->type == OBJT_SWAP)) { 1221 VM_OBJECT_WUNLOCK(source); 1222 return; 1223 } 1224 VM_OBJECT_WUNLOCK(source); 1225 } 1226 1227 /* 1228 * Allocate a new object with the given length. 1229 */ 1230 result = vm_object_allocate(OBJT_DEFAULT, atop(length)); 1231 1232 /* 1233 * The new object shadows the source object, adding a reference to it. 1234 * Our caller changes his reference to point to the new object, 1235 * removing a reference to the source object. Net result: no change 1236 * of reference count. 1237 * 1238 * Try to optimize the result object's page color when shadowing 1239 * in order to maintain page coloring consistency in the combined 1240 * shadowed object. 1241 */ 1242 result->backing_object = source; 1243 /* 1244 * Store the offset into the source object, and fix up the offset into 1245 * the new object. 1246 */ 1247 result->backing_object_offset = *offset; 1248 if (source != NULL) { 1249 VM_OBJECT_WLOCK(source); 1250 LIST_INSERT_HEAD(&source->shadow_head, result, shadow_list); 1251 source->shadow_count++; 1252 #if VM_NRESERVLEVEL > 0 1253 result->flags |= source->flags & OBJ_COLORED; 1254 result->pg_color = (source->pg_color + OFF_TO_IDX(*offset)) & 1255 ((1 << (VM_NFREEORDER - 1)) - 1); 1256 #endif 1257 VM_OBJECT_WUNLOCK(source); 1258 } 1259 1260 1261 /* 1262 * Return the new things 1263 */ 1264 *offset = 0; 1265 *object = result; 1266 } 1267 1268 /* 1269 * vm_object_split: 1270 * 1271 * Split the pages in a map entry into a new object. This affords 1272 * easier removal of unused pages, and keeps object inheritance from 1273 * being a negative impact on memory usage. 1274 */ 1275 void 1276 vm_object_split(vm_map_entry_t entry) 1277 { 1278 vm_page_t m, m_next; 1279 vm_object_t orig_object, new_object, source; 1280 vm_pindex_t idx, offidxstart; 1281 vm_size_t size; 1282 1283 orig_object = entry->object.vm_object; 1284 if (orig_object->type != OBJT_DEFAULT && orig_object->type != OBJT_SWAP) 1285 return; 1286 if (orig_object->ref_count <= 1) 1287 return; 1288 VM_OBJECT_WUNLOCK(orig_object); 1289 1290 offidxstart = OFF_TO_IDX(entry->offset); 1291 size = atop(entry->end - entry->start); 1292 1293 /* 1294 * If swap_pager_copy() is later called, it will convert new_object 1295 * into a swap object. 1296 */ 1297 new_object = vm_object_allocate(OBJT_DEFAULT, size); 1298 1299 /* 1300 * At this point, the new object is still private, so the order in 1301 * which the original and new objects are locked does not matter. 1302 */ 1303 VM_OBJECT_WLOCK(new_object); 1304 VM_OBJECT_WLOCK(orig_object); 1305 source = orig_object->backing_object; 1306 if (source != NULL) { 1307 VM_OBJECT_WLOCK(source); 1308 if ((source->flags & OBJ_DEAD) != 0) { 1309 VM_OBJECT_WUNLOCK(source); 1310 VM_OBJECT_WUNLOCK(orig_object); 1311 VM_OBJECT_WUNLOCK(new_object); 1312 vm_object_deallocate(new_object); 1313 VM_OBJECT_WLOCK(orig_object); 1314 return; 1315 } 1316 LIST_INSERT_HEAD(&source->shadow_head, 1317 new_object, shadow_list); 1318 source->shadow_count++; 1319 vm_object_reference_locked(source); /* for new_object */ 1320 vm_object_clear_flag(source, OBJ_ONEMAPPING); 1321 VM_OBJECT_WUNLOCK(source); 1322 new_object->backing_object_offset = 1323 orig_object->backing_object_offset + entry->offset; 1324 new_object->backing_object = source; 1325 } 1326 if (orig_object->cred != NULL) { 1327 new_object->cred = orig_object->cred; 1328 crhold(orig_object->cred); 1329 new_object->charge = ptoa(size); 1330 KASSERT(orig_object->charge >= ptoa(size), 1331 ("orig_object->charge < 0")); 1332 orig_object->charge -= ptoa(size); 1333 } 1334 retry: 1335 m = vm_page_find_least(orig_object, offidxstart); 1336 for (; m != NULL && (idx = m->pindex - offidxstart) < size; 1337 m = m_next) { 1338 m_next = TAILQ_NEXT(m, listq); 1339 1340 /* 1341 * We must wait for pending I/O to complete before we can 1342 * rename the page. 1343 * 1344 * We do not have to VM_PROT_NONE the page as mappings should 1345 * not be changed by this operation. 1346 */ 1347 if (vm_page_busied(m)) { 1348 VM_OBJECT_WUNLOCK(new_object); 1349 vm_page_lock(m); 1350 VM_OBJECT_WUNLOCK(orig_object); 1351 vm_page_busy_sleep(m, "spltwt"); 1352 VM_OBJECT_WLOCK(orig_object); 1353 VM_OBJECT_WLOCK(new_object); 1354 goto retry; 1355 } 1356 1357 /* vm_page_rename() will handle dirty and cache. */ 1358 if (vm_page_rename(m, new_object, idx)) { 1359 VM_OBJECT_WUNLOCK(new_object); 1360 VM_OBJECT_WUNLOCK(orig_object); 1361 VM_WAIT; 1362 VM_OBJECT_WLOCK(orig_object); 1363 VM_OBJECT_WLOCK(new_object); 1364 goto retry; 1365 } 1366 #if VM_NRESERVLEVEL > 0 1367 /* 1368 * If some of the reservation's allocated pages remain with 1369 * the original object, then transferring the reservation to 1370 * the new object is neither particularly beneficial nor 1371 * particularly harmful as compared to leaving the reservation 1372 * with the original object. If, however, all of the 1373 * reservation's allocated pages are transferred to the new 1374 * object, then transferring the reservation is typically 1375 * beneficial. Determining which of these two cases applies 1376 * would be more costly than unconditionally renaming the 1377 * reservation. 1378 */ 1379 vm_reserv_rename(m, new_object, orig_object, offidxstart); 1380 #endif 1381 if (orig_object->type == OBJT_SWAP) 1382 vm_page_xbusy(m); 1383 } 1384 if (orig_object->type == OBJT_SWAP) { 1385 /* 1386 * swap_pager_copy() can sleep, in which case the orig_object's 1387 * and new_object's locks are released and reacquired. 1388 */ 1389 swap_pager_copy(orig_object, new_object, offidxstart, 0); 1390 TAILQ_FOREACH(m, &new_object->memq, listq) 1391 vm_page_xunbusy(m); 1392 1393 /* 1394 * Transfer any cached pages from orig_object to new_object. 1395 * If swap_pager_copy() found swapped out pages within the 1396 * specified range of orig_object, then it changed 1397 * new_object's type to OBJT_SWAP when it transferred those 1398 * pages to new_object. Otherwise, new_object's type 1399 * should still be OBJT_DEFAULT and orig_object should not 1400 * contain any cached pages within the specified range. 1401 */ 1402 if (__predict_false(!vm_object_cache_is_empty(orig_object))) 1403 vm_page_cache_transfer(orig_object, offidxstart, 1404 new_object); 1405 } 1406 VM_OBJECT_WUNLOCK(orig_object); 1407 VM_OBJECT_WUNLOCK(new_object); 1408 entry->object.vm_object = new_object; 1409 entry->offset = 0LL; 1410 vm_object_deallocate(orig_object); 1411 VM_OBJECT_WLOCK(new_object); 1412 } 1413 1414 #define OBSC_TEST_ALL_SHADOWED 0x0001 1415 #define OBSC_COLLAPSE_NOWAIT 0x0002 1416 #define OBSC_COLLAPSE_WAIT 0x0004 1417 1418 static int 1419 vm_object_backing_scan(vm_object_t object, int op) 1420 { 1421 int r = 1; 1422 vm_page_t p; 1423 vm_object_t backing_object; 1424 vm_pindex_t backing_offset_index; 1425 1426 VM_OBJECT_ASSERT_WLOCKED(object); 1427 VM_OBJECT_ASSERT_WLOCKED(object->backing_object); 1428 1429 backing_object = object->backing_object; 1430 backing_offset_index = OFF_TO_IDX(object->backing_object_offset); 1431 1432 /* 1433 * Initial conditions 1434 */ 1435 if (op & OBSC_TEST_ALL_SHADOWED) { 1436 /* 1437 * We do not want to have to test for the existence of cache 1438 * or swap pages in the backing object. XXX but with the 1439 * new swapper this would be pretty easy to do. 1440 * 1441 * XXX what about anonymous MAP_SHARED memory that hasn't 1442 * been ZFOD faulted yet? If we do not test for this, the 1443 * shadow test may succeed! XXX 1444 */ 1445 if (backing_object->type != OBJT_DEFAULT) { 1446 return (0); 1447 } 1448 } 1449 if (op & OBSC_COLLAPSE_WAIT) { 1450 vm_object_set_flag(backing_object, OBJ_DEAD); 1451 } 1452 1453 /* 1454 * Our scan 1455 */ 1456 p = TAILQ_FIRST(&backing_object->memq); 1457 while (p) { 1458 vm_page_t next = TAILQ_NEXT(p, listq); 1459 vm_pindex_t new_pindex = p->pindex - backing_offset_index; 1460 1461 if (op & OBSC_TEST_ALL_SHADOWED) { 1462 vm_page_t pp; 1463 1464 /* 1465 * Ignore pages outside the parent object's range 1466 * and outside the parent object's mapping of the 1467 * backing object. 1468 * 1469 * note that we do not busy the backing object's 1470 * page. 1471 */ 1472 if ( 1473 p->pindex < backing_offset_index || 1474 new_pindex >= object->size 1475 ) { 1476 p = next; 1477 continue; 1478 } 1479 1480 /* 1481 * See if the parent has the page or if the parent's 1482 * object pager has the page. If the parent has the 1483 * page but the page is not valid, the parent's 1484 * object pager must have the page. 1485 * 1486 * If this fails, the parent does not completely shadow 1487 * the object and we might as well give up now. 1488 */ 1489 1490 pp = vm_page_lookup(object, new_pindex); 1491 if ( 1492 (pp == NULL || pp->valid == 0) && 1493 !vm_pager_has_page(object, new_pindex, NULL, NULL) 1494 ) { 1495 r = 0; 1496 break; 1497 } 1498 } 1499 1500 /* 1501 * Check for busy page 1502 */ 1503 if (op & (OBSC_COLLAPSE_WAIT | OBSC_COLLAPSE_NOWAIT)) { 1504 vm_page_t pp; 1505 1506 if (op & OBSC_COLLAPSE_NOWAIT) { 1507 if (!p->valid || vm_page_busied(p)) { 1508 p = next; 1509 continue; 1510 } 1511 } else if (op & OBSC_COLLAPSE_WAIT) { 1512 if (vm_page_busied(p)) { 1513 VM_OBJECT_WUNLOCK(object); 1514 vm_page_lock(p); 1515 VM_OBJECT_WUNLOCK(backing_object); 1516 vm_page_busy_sleep(p, "vmocol"); 1517 VM_OBJECT_WLOCK(object); 1518 VM_OBJECT_WLOCK(backing_object); 1519 /* 1520 * If we slept, anything could have 1521 * happened. Since the object is 1522 * marked dead, the backing offset 1523 * should not have changed so we 1524 * just restart our scan. 1525 */ 1526 p = TAILQ_FIRST(&backing_object->memq); 1527 continue; 1528 } 1529 } 1530 1531 KASSERT( 1532 p->object == backing_object, 1533 ("vm_object_backing_scan: object mismatch") 1534 ); 1535 1536 if ( 1537 p->pindex < backing_offset_index || 1538 new_pindex >= object->size 1539 ) { 1540 if (backing_object->type == OBJT_SWAP) 1541 swap_pager_freespace(backing_object, 1542 p->pindex, 1); 1543 1544 /* 1545 * Page is out of the parent object's range, we 1546 * can simply destroy it. 1547 */ 1548 vm_page_lock(p); 1549 KASSERT(!pmap_page_is_mapped(p), 1550 ("freeing mapped page %p", p)); 1551 if (p->wire_count == 0) 1552 vm_page_free(p); 1553 else 1554 vm_page_remove(p); 1555 vm_page_unlock(p); 1556 p = next; 1557 continue; 1558 } 1559 1560 pp = vm_page_lookup(object, new_pindex); 1561 if ( 1562 (op & OBSC_COLLAPSE_NOWAIT) != 0 && 1563 (pp != NULL && pp->valid == 0) 1564 ) { 1565 if (backing_object->type == OBJT_SWAP) 1566 swap_pager_freespace(backing_object, 1567 p->pindex, 1); 1568 1569 /* 1570 * The page in the parent is not (yet) valid. 1571 * We don't know anything about the state of 1572 * the original page. It might be mapped, 1573 * so we must avoid the next if here. 1574 * 1575 * This is due to a race in vm_fault() where 1576 * we must unbusy the original (backing_obj) 1577 * page before we can (re)lock the parent. 1578 * Hence we can get here. 1579 */ 1580 p = next; 1581 continue; 1582 } 1583 if ( 1584 pp != NULL || 1585 vm_pager_has_page(object, new_pindex, NULL, NULL) 1586 ) { 1587 if (backing_object->type == OBJT_SWAP) 1588 swap_pager_freespace(backing_object, 1589 p->pindex, 1); 1590 1591 /* 1592 * page already exists in parent OR swap exists 1593 * for this location in the parent. Destroy 1594 * the original page from the backing object. 1595 * 1596 * Leave the parent's page alone 1597 */ 1598 vm_page_lock(p); 1599 KASSERT(!pmap_page_is_mapped(p), 1600 ("freeing mapped page %p", p)); 1601 if (p->wire_count == 0) 1602 vm_page_free(p); 1603 else 1604 vm_page_remove(p); 1605 vm_page_unlock(p); 1606 p = next; 1607 continue; 1608 } 1609 1610 /* 1611 * Page does not exist in parent, rename the 1612 * page from the backing object to the main object. 1613 * 1614 * If the page was mapped to a process, it can remain 1615 * mapped through the rename. 1616 * vm_page_rename() will handle dirty and cache. 1617 */ 1618 if (vm_page_rename(p, object, new_pindex)) { 1619 if (op & OBSC_COLLAPSE_NOWAIT) { 1620 p = next; 1621 continue; 1622 } 1623 VM_OBJECT_WLOCK(backing_object); 1624 VM_OBJECT_WUNLOCK(object); 1625 VM_WAIT; 1626 VM_OBJECT_WLOCK(object); 1627 VM_OBJECT_WLOCK(backing_object); 1628 p = TAILQ_FIRST(&backing_object->memq); 1629 continue; 1630 } 1631 1632 /* Use the old pindex to free the right page. */ 1633 if (backing_object->type == OBJT_SWAP) 1634 swap_pager_freespace(backing_object, 1635 new_pindex + backing_offset_index, 1); 1636 1637 #if VM_NRESERVLEVEL > 0 1638 /* 1639 * Rename the reservation. 1640 */ 1641 vm_reserv_rename(p, object, backing_object, 1642 backing_offset_index); 1643 #endif 1644 } 1645 p = next; 1646 } 1647 return (r); 1648 } 1649 1650 1651 /* 1652 * this version of collapse allows the operation to occur earlier and 1653 * when paging_in_progress is true for an object... This is not a complete 1654 * operation, but should plug 99.9% of the rest of the leaks. 1655 */ 1656 static void 1657 vm_object_qcollapse(vm_object_t object) 1658 { 1659 vm_object_t backing_object = object->backing_object; 1660 1661 VM_OBJECT_ASSERT_WLOCKED(object); 1662 VM_OBJECT_ASSERT_WLOCKED(backing_object); 1663 1664 if (backing_object->ref_count != 1) 1665 return; 1666 1667 vm_object_backing_scan(object, OBSC_COLLAPSE_NOWAIT); 1668 } 1669 1670 /* 1671 * vm_object_collapse: 1672 * 1673 * Collapse an object with the object backing it. 1674 * Pages in the backing object are moved into the 1675 * parent, and the backing object is deallocated. 1676 */ 1677 void 1678 vm_object_collapse(vm_object_t object) 1679 { 1680 VM_OBJECT_ASSERT_WLOCKED(object); 1681 1682 while (TRUE) { 1683 vm_object_t backing_object; 1684 1685 /* 1686 * Verify that the conditions are right for collapse: 1687 * 1688 * The object exists and the backing object exists. 1689 */ 1690 if ((backing_object = object->backing_object) == NULL) 1691 break; 1692 1693 /* 1694 * we check the backing object first, because it is most likely 1695 * not collapsable. 1696 */ 1697 VM_OBJECT_WLOCK(backing_object); 1698 if (backing_object->handle != NULL || 1699 (backing_object->type != OBJT_DEFAULT && 1700 backing_object->type != OBJT_SWAP) || 1701 (backing_object->flags & OBJ_DEAD) || 1702 object->handle != NULL || 1703 (object->type != OBJT_DEFAULT && 1704 object->type != OBJT_SWAP) || 1705 (object->flags & OBJ_DEAD)) { 1706 VM_OBJECT_WUNLOCK(backing_object); 1707 break; 1708 } 1709 1710 if ( 1711 object->paging_in_progress != 0 || 1712 backing_object->paging_in_progress != 0 1713 ) { 1714 vm_object_qcollapse(object); 1715 VM_OBJECT_WUNLOCK(backing_object); 1716 break; 1717 } 1718 /* 1719 * We know that we can either collapse the backing object (if 1720 * the parent is the only reference to it) or (perhaps) have 1721 * the parent bypass the object if the parent happens to shadow 1722 * all the resident pages in the entire backing object. 1723 * 1724 * This is ignoring pager-backed pages such as swap pages. 1725 * vm_object_backing_scan fails the shadowing test in this 1726 * case. 1727 */ 1728 if (backing_object->ref_count == 1) { 1729 /* 1730 * If there is exactly one reference to the backing 1731 * object, we can collapse it into the parent. 1732 */ 1733 vm_object_backing_scan(object, OBSC_COLLAPSE_WAIT); 1734 1735 #if VM_NRESERVLEVEL > 0 1736 /* 1737 * Break any reservations from backing_object. 1738 */ 1739 if (__predict_false(!LIST_EMPTY(&backing_object->rvq))) 1740 vm_reserv_break_all(backing_object); 1741 #endif 1742 1743 /* 1744 * Move the pager from backing_object to object. 1745 */ 1746 if (backing_object->type == OBJT_SWAP) { 1747 /* 1748 * swap_pager_copy() can sleep, in which case 1749 * the backing_object's and object's locks are 1750 * released and reacquired. 1751 * Since swap_pager_copy() is being asked to 1752 * destroy the source, it will change the 1753 * backing_object's type to OBJT_DEFAULT. 1754 */ 1755 swap_pager_copy( 1756 backing_object, 1757 object, 1758 OFF_TO_IDX(object->backing_object_offset), TRUE); 1759 1760 /* 1761 * Free any cached pages from backing_object. 1762 */ 1763 if (__predict_false( 1764 !vm_object_cache_is_empty(backing_object))) 1765 vm_page_cache_free(backing_object, 0, 0); 1766 } 1767 /* 1768 * Object now shadows whatever backing_object did. 1769 * Note that the reference to 1770 * backing_object->backing_object moves from within 1771 * backing_object to within object. 1772 */ 1773 LIST_REMOVE(object, shadow_list); 1774 backing_object->shadow_count--; 1775 if (backing_object->backing_object) { 1776 VM_OBJECT_WLOCK(backing_object->backing_object); 1777 LIST_REMOVE(backing_object, shadow_list); 1778 LIST_INSERT_HEAD( 1779 &backing_object->backing_object->shadow_head, 1780 object, shadow_list); 1781 /* 1782 * The shadow_count has not changed. 1783 */ 1784 VM_OBJECT_WUNLOCK(backing_object->backing_object); 1785 } 1786 object->backing_object = backing_object->backing_object; 1787 object->backing_object_offset += 1788 backing_object->backing_object_offset; 1789 1790 /* 1791 * Discard backing_object. 1792 * 1793 * Since the backing object has no pages, no pager left, 1794 * and no object references within it, all that is 1795 * necessary is to dispose of it. 1796 */ 1797 KASSERT(backing_object->ref_count == 1, ( 1798 "backing_object %p was somehow re-referenced during collapse!", 1799 backing_object)); 1800 VM_OBJECT_WUNLOCK(backing_object); 1801 vm_object_destroy(backing_object); 1802 1803 object_collapses++; 1804 } else { 1805 vm_object_t new_backing_object; 1806 1807 /* 1808 * If we do not entirely shadow the backing object, 1809 * there is nothing we can do so we give up. 1810 */ 1811 if (object->resident_page_count != object->size && 1812 vm_object_backing_scan(object, 1813 OBSC_TEST_ALL_SHADOWED) == 0) { 1814 VM_OBJECT_WUNLOCK(backing_object); 1815 break; 1816 } 1817 1818 /* 1819 * Make the parent shadow the next object in the 1820 * chain. Deallocating backing_object will not remove 1821 * it, since its reference count is at least 2. 1822 */ 1823 LIST_REMOVE(object, shadow_list); 1824 backing_object->shadow_count--; 1825 1826 new_backing_object = backing_object->backing_object; 1827 if ((object->backing_object = new_backing_object) != NULL) { 1828 VM_OBJECT_WLOCK(new_backing_object); 1829 LIST_INSERT_HEAD( 1830 &new_backing_object->shadow_head, 1831 object, 1832 shadow_list 1833 ); 1834 new_backing_object->shadow_count++; 1835 vm_object_reference_locked(new_backing_object); 1836 VM_OBJECT_WUNLOCK(new_backing_object); 1837 object->backing_object_offset += 1838 backing_object->backing_object_offset; 1839 } 1840 1841 /* 1842 * Drop the reference count on backing_object. Since 1843 * its ref_count was at least 2, it will not vanish. 1844 */ 1845 backing_object->ref_count--; 1846 VM_OBJECT_WUNLOCK(backing_object); 1847 object_bypasses++; 1848 } 1849 1850 /* 1851 * Try again with this object's new backing object. 1852 */ 1853 } 1854 } 1855 1856 /* 1857 * vm_object_page_remove: 1858 * 1859 * For the given object, either frees or invalidates each of the 1860 * specified pages. In general, a page is freed. However, if a page is 1861 * wired for any reason other than the existence of a managed, wired 1862 * mapping, then it may be invalidated but not removed from the object. 1863 * Pages are specified by the given range ["start", "end") and the option 1864 * OBJPR_CLEANONLY. As a special case, if "end" is zero, then the range 1865 * extends from "start" to the end of the object. If the option 1866 * OBJPR_CLEANONLY is specified, then only the non-dirty pages within the 1867 * specified range are affected. If the option OBJPR_NOTMAPPED is 1868 * specified, then the pages within the specified range must have no 1869 * mappings. Otherwise, if this option is not specified, any mappings to 1870 * the specified pages are removed before the pages are freed or 1871 * invalidated. 1872 * 1873 * In general, this operation should only be performed on objects that 1874 * contain managed pages. There are, however, two exceptions. First, it 1875 * is performed on the kernel and kmem objects by vm_map_entry_delete(). 1876 * Second, it is used by msync(..., MS_INVALIDATE) to invalidate device- 1877 * backed pages. In both of these cases, the option OBJPR_CLEANONLY must 1878 * not be specified and the option OBJPR_NOTMAPPED must be specified. 1879 * 1880 * The object must be locked. 1881 */ 1882 void 1883 vm_object_page_remove(vm_object_t object, vm_pindex_t start, vm_pindex_t end, 1884 int options) 1885 { 1886 vm_page_t p, next; 1887 int wirings; 1888 1889 VM_OBJECT_ASSERT_WLOCKED(object); 1890 KASSERT((object->flags & OBJ_UNMANAGED) == 0 || 1891 (options & (OBJPR_CLEANONLY | OBJPR_NOTMAPPED)) == OBJPR_NOTMAPPED, 1892 ("vm_object_page_remove: illegal options for object %p", object)); 1893 if (object->resident_page_count == 0) 1894 goto skipmemq; 1895 vm_object_pip_add(object, 1); 1896 again: 1897 p = vm_page_find_least(object, start); 1898 1899 /* 1900 * Here, the variable "p" is either (1) the page with the least pindex 1901 * greater than or equal to the parameter "start" or (2) NULL. 1902 */ 1903 for (; p != NULL && (p->pindex < end || end == 0); p = next) { 1904 next = TAILQ_NEXT(p, listq); 1905 1906 /* 1907 * If the page is wired for any reason besides the existence 1908 * of managed, wired mappings, then it cannot be freed. For 1909 * example, fictitious pages, which represent device memory, 1910 * are inherently wired and cannot be freed. They can, 1911 * however, be invalidated if the option OBJPR_CLEANONLY is 1912 * not specified. 1913 */ 1914 vm_page_lock(p); 1915 if (vm_page_xbusied(p)) { 1916 VM_OBJECT_WUNLOCK(object); 1917 vm_page_busy_sleep(p, "vmopax"); 1918 VM_OBJECT_WLOCK(object); 1919 goto again; 1920 } 1921 if ((wirings = p->wire_count) != 0 && 1922 (wirings = pmap_page_wired_mappings(p)) != p->wire_count) { 1923 if ((options & (OBJPR_NOTWIRED | OBJPR_NOTMAPPED)) == 1924 0) { 1925 pmap_remove_all(p); 1926 /* Account for removal of wired mappings. */ 1927 if (wirings != 0) 1928 p->wire_count -= wirings; 1929 } 1930 if ((options & OBJPR_CLEANONLY) == 0) { 1931 p->valid = 0; 1932 vm_page_undirty(p); 1933 } 1934 goto next; 1935 } 1936 if (vm_page_busied(p)) { 1937 VM_OBJECT_WUNLOCK(object); 1938 vm_page_busy_sleep(p, "vmopar"); 1939 VM_OBJECT_WLOCK(object); 1940 goto again; 1941 } 1942 KASSERT((p->flags & PG_FICTITIOUS) == 0, 1943 ("vm_object_page_remove: page %p is fictitious", p)); 1944 if ((options & OBJPR_CLEANONLY) != 0 && p->valid != 0) { 1945 if ((options & OBJPR_NOTMAPPED) == 0) 1946 pmap_remove_write(p); 1947 if (p->dirty) 1948 goto next; 1949 } 1950 if ((options & OBJPR_NOTMAPPED) == 0) { 1951 if ((options & OBJPR_NOTWIRED) != 0 && wirings != 0) 1952 goto next; 1953 pmap_remove_all(p); 1954 /* Account for removal of wired mappings. */ 1955 if (wirings != 0) { 1956 KASSERT(p->wire_count == wirings, 1957 ("inconsistent wire count %d %d %p", 1958 p->wire_count, wirings, p)); 1959 p->wire_count = 0; 1960 atomic_subtract_int(&vm_cnt.v_wire_count, 1); 1961 } 1962 } 1963 vm_page_free(p); 1964 next: 1965 vm_page_unlock(p); 1966 } 1967 vm_object_pip_wakeup(object); 1968 skipmemq: 1969 if (__predict_false(!vm_object_cache_is_empty(object))) 1970 vm_page_cache_free(object, start, end); 1971 } 1972 1973 /* 1974 * vm_object_page_cache: 1975 * 1976 * For the given object, attempt to move the specified clean 1977 * pages to the cache queue. If a page is wired for any reason, 1978 * then it will not be changed. Pages are specified by the given 1979 * range ["start", "end"). As a special case, if "end" is zero, 1980 * then the range extends from "start" to the end of the object. 1981 * Any mappings to the specified pages are removed before the 1982 * pages are moved to the cache queue. 1983 * 1984 * This operation should only be performed on objects that 1985 * contain non-fictitious, managed pages. 1986 * 1987 * The object must be locked. 1988 */ 1989 void 1990 vm_object_page_cache(vm_object_t object, vm_pindex_t start, vm_pindex_t end) 1991 { 1992 struct mtx *mtx, *new_mtx; 1993 vm_page_t p, next; 1994 1995 VM_OBJECT_ASSERT_WLOCKED(object); 1996 KASSERT((object->flags & (OBJ_FICTITIOUS | OBJ_UNMANAGED)) == 0, 1997 ("vm_object_page_cache: illegal object %p", object)); 1998 if (object->resident_page_count == 0) 1999 return; 2000 p = vm_page_find_least(object, start); 2001 2002 /* 2003 * Here, the variable "p" is either (1) the page with the least pindex 2004 * greater than or equal to the parameter "start" or (2) NULL. 2005 */ 2006 mtx = NULL; 2007 for (; p != NULL && (p->pindex < end || end == 0); p = next) { 2008 next = TAILQ_NEXT(p, listq); 2009 2010 /* 2011 * Avoid releasing and reacquiring the same page lock. 2012 */ 2013 new_mtx = vm_page_lockptr(p); 2014 if (mtx != new_mtx) { 2015 if (mtx != NULL) 2016 mtx_unlock(mtx); 2017 mtx = new_mtx; 2018 mtx_lock(mtx); 2019 } 2020 vm_page_try_to_cache(p); 2021 } 2022 if (mtx != NULL) 2023 mtx_unlock(mtx); 2024 } 2025 2026 /* 2027 * Populate the specified range of the object with valid pages. Returns 2028 * TRUE if the range is successfully populated and FALSE otherwise. 2029 * 2030 * Note: This function should be optimized to pass a larger array of 2031 * pages to vm_pager_get_pages() before it is applied to a non- 2032 * OBJT_DEVICE object. 2033 * 2034 * The object must be locked. 2035 */ 2036 boolean_t 2037 vm_object_populate(vm_object_t object, vm_pindex_t start, vm_pindex_t end) 2038 { 2039 vm_page_t m, ma[1]; 2040 vm_pindex_t pindex; 2041 int rv; 2042 2043 VM_OBJECT_ASSERT_WLOCKED(object); 2044 for (pindex = start; pindex < end; pindex++) { 2045 m = vm_page_grab(object, pindex, VM_ALLOC_NORMAL); 2046 if (m->valid != VM_PAGE_BITS_ALL) { 2047 ma[0] = m; 2048 rv = vm_pager_get_pages(object, ma, 1, 0); 2049 m = vm_page_lookup(object, pindex); 2050 if (m == NULL) 2051 break; 2052 if (rv != VM_PAGER_OK) { 2053 vm_page_lock(m); 2054 vm_page_free(m); 2055 vm_page_unlock(m); 2056 break; 2057 } 2058 } 2059 /* 2060 * Keep "m" busy because a subsequent iteration may unlock 2061 * the object. 2062 */ 2063 } 2064 if (pindex > start) { 2065 m = vm_page_lookup(object, start); 2066 while (m != NULL && m->pindex < pindex) { 2067 vm_page_xunbusy(m); 2068 m = TAILQ_NEXT(m, listq); 2069 } 2070 } 2071 return (pindex == end); 2072 } 2073 2074 /* 2075 * Routine: vm_object_coalesce 2076 * Function: Coalesces two objects backing up adjoining 2077 * regions of memory into a single object. 2078 * 2079 * returns TRUE if objects were combined. 2080 * 2081 * NOTE: Only works at the moment if the second object is NULL - 2082 * if it's not, which object do we lock first? 2083 * 2084 * Parameters: 2085 * prev_object First object to coalesce 2086 * prev_offset Offset into prev_object 2087 * prev_size Size of reference to prev_object 2088 * next_size Size of reference to the second object 2089 * reserved Indicator that extension region has 2090 * swap accounted for 2091 * 2092 * Conditions: 2093 * The object must *not* be locked. 2094 */ 2095 boolean_t 2096 vm_object_coalesce(vm_object_t prev_object, vm_ooffset_t prev_offset, 2097 vm_size_t prev_size, vm_size_t next_size, boolean_t reserved) 2098 { 2099 vm_pindex_t next_pindex; 2100 2101 if (prev_object == NULL) 2102 return (TRUE); 2103 VM_OBJECT_WLOCK(prev_object); 2104 if ((prev_object->type != OBJT_DEFAULT && 2105 prev_object->type != OBJT_SWAP) || 2106 (prev_object->flags & OBJ_TMPFS) != 0) { 2107 VM_OBJECT_WUNLOCK(prev_object); 2108 return (FALSE); 2109 } 2110 2111 /* 2112 * Try to collapse the object first 2113 */ 2114 vm_object_collapse(prev_object); 2115 2116 /* 2117 * Can't coalesce if: . more than one reference . paged out . shadows 2118 * another object . has a copy elsewhere (any of which mean that the 2119 * pages not mapped to prev_entry may be in use anyway) 2120 */ 2121 if (prev_object->backing_object != NULL) { 2122 VM_OBJECT_WUNLOCK(prev_object); 2123 return (FALSE); 2124 } 2125 2126 prev_size >>= PAGE_SHIFT; 2127 next_size >>= PAGE_SHIFT; 2128 next_pindex = OFF_TO_IDX(prev_offset) + prev_size; 2129 2130 if ((prev_object->ref_count > 1) && 2131 (prev_object->size != next_pindex)) { 2132 VM_OBJECT_WUNLOCK(prev_object); 2133 return (FALSE); 2134 } 2135 2136 /* 2137 * Account for the charge. 2138 */ 2139 if (prev_object->cred != NULL) { 2140 2141 /* 2142 * If prev_object was charged, then this mapping, 2143 * althought not charged now, may become writable 2144 * later. Non-NULL cred in the object would prevent 2145 * swap reservation during enabling of the write 2146 * access, so reserve swap now. Failed reservation 2147 * cause allocation of the separate object for the map 2148 * entry, and swap reservation for this entry is 2149 * managed in appropriate time. 2150 */ 2151 if (!reserved && !swap_reserve_by_cred(ptoa(next_size), 2152 prev_object->cred)) { 2153 return (FALSE); 2154 } 2155 prev_object->charge += ptoa(next_size); 2156 } 2157 2158 /* 2159 * Remove any pages that may still be in the object from a previous 2160 * deallocation. 2161 */ 2162 if (next_pindex < prev_object->size) { 2163 vm_object_page_remove(prev_object, next_pindex, next_pindex + 2164 next_size, 0); 2165 if (prev_object->type == OBJT_SWAP) 2166 swap_pager_freespace(prev_object, 2167 next_pindex, next_size); 2168 #if 0 2169 if (prev_object->cred != NULL) { 2170 KASSERT(prev_object->charge >= 2171 ptoa(prev_object->size - next_pindex), 2172 ("object %p overcharged 1 %jx %jx", prev_object, 2173 (uintmax_t)next_pindex, (uintmax_t)next_size)); 2174 prev_object->charge -= ptoa(prev_object->size - 2175 next_pindex); 2176 } 2177 #endif 2178 } 2179 2180 /* 2181 * Extend the object if necessary. 2182 */ 2183 if (next_pindex + next_size > prev_object->size) 2184 prev_object->size = next_pindex + next_size; 2185 2186 VM_OBJECT_WUNLOCK(prev_object); 2187 return (TRUE); 2188 } 2189 2190 void 2191 vm_object_set_writeable_dirty(vm_object_t object) 2192 { 2193 2194 VM_OBJECT_ASSERT_WLOCKED(object); 2195 if (object->type != OBJT_VNODE) 2196 return; 2197 object->generation++; 2198 if ((object->flags & OBJ_MIGHTBEDIRTY) != 0) 2199 return; 2200 vm_object_set_flag(object, OBJ_MIGHTBEDIRTY); 2201 } 2202 2203 #include "opt_ddb.h" 2204 #ifdef DDB 2205 #include <sys/kernel.h> 2206 2207 #include <sys/cons.h> 2208 2209 #include <ddb/ddb.h> 2210 2211 static int 2212 _vm_object_in_map(vm_map_t map, vm_object_t object, vm_map_entry_t entry) 2213 { 2214 vm_map_t tmpm; 2215 vm_map_entry_t tmpe; 2216 vm_object_t obj; 2217 int entcount; 2218 2219 if (map == 0) 2220 return 0; 2221 2222 if (entry == 0) { 2223 tmpe = map->header.next; 2224 entcount = map->nentries; 2225 while (entcount-- && (tmpe != &map->header)) { 2226 if (_vm_object_in_map(map, object, tmpe)) { 2227 return 1; 2228 } 2229 tmpe = tmpe->next; 2230 } 2231 } else if (entry->eflags & MAP_ENTRY_IS_SUB_MAP) { 2232 tmpm = entry->object.sub_map; 2233 tmpe = tmpm->header.next; 2234 entcount = tmpm->nentries; 2235 while (entcount-- && tmpe != &tmpm->header) { 2236 if (_vm_object_in_map(tmpm, object, tmpe)) { 2237 return 1; 2238 } 2239 tmpe = tmpe->next; 2240 } 2241 } else if ((obj = entry->object.vm_object) != NULL) { 2242 for (; obj; obj = obj->backing_object) 2243 if (obj == object) { 2244 return 1; 2245 } 2246 } 2247 return 0; 2248 } 2249 2250 static int 2251 vm_object_in_map(vm_object_t object) 2252 { 2253 struct proc *p; 2254 2255 /* sx_slock(&allproc_lock); */ 2256 FOREACH_PROC_IN_SYSTEM(p) { 2257 if (!p->p_vmspace /* || (p->p_flag & (P_SYSTEM|P_WEXIT)) */) 2258 continue; 2259 if (_vm_object_in_map(&p->p_vmspace->vm_map, object, 0)) { 2260 /* sx_sunlock(&allproc_lock); */ 2261 return 1; 2262 } 2263 } 2264 /* sx_sunlock(&allproc_lock); */ 2265 if (_vm_object_in_map(kernel_map, object, 0)) 2266 return 1; 2267 return 0; 2268 } 2269 2270 DB_SHOW_COMMAND(vmochk, vm_object_check) 2271 { 2272 vm_object_t object; 2273 2274 /* 2275 * make sure that internal objs are in a map somewhere 2276 * and none have zero ref counts. 2277 */ 2278 TAILQ_FOREACH(object, &vm_object_list, object_list) { 2279 if (object->handle == NULL && 2280 (object->type == OBJT_DEFAULT || object->type == OBJT_SWAP)) { 2281 if (object->ref_count == 0) { 2282 db_printf("vmochk: internal obj has zero ref count: %ld\n", 2283 (long)object->size); 2284 } 2285 if (!vm_object_in_map(object)) { 2286 db_printf( 2287 "vmochk: internal obj is not in a map: " 2288 "ref: %d, size: %lu: 0x%lx, backing_object: %p\n", 2289 object->ref_count, (u_long)object->size, 2290 (u_long)object->size, 2291 (void *)object->backing_object); 2292 } 2293 } 2294 } 2295 } 2296 2297 /* 2298 * vm_object_print: [ debug ] 2299 */ 2300 DB_SHOW_COMMAND(object, vm_object_print_static) 2301 { 2302 /* XXX convert args. */ 2303 vm_object_t object = (vm_object_t)addr; 2304 boolean_t full = have_addr; 2305 2306 vm_page_t p; 2307 2308 /* XXX count is an (unused) arg. Avoid shadowing it. */ 2309 #define count was_count 2310 2311 int count; 2312 2313 if (object == NULL) 2314 return; 2315 2316 db_iprintf( 2317 "Object %p: type=%d, size=0x%jx, res=%d, ref=%d, flags=0x%x ruid %d charge %jx\n", 2318 object, (int)object->type, (uintmax_t)object->size, 2319 object->resident_page_count, object->ref_count, object->flags, 2320 object->cred ? object->cred->cr_ruid : -1, (uintmax_t)object->charge); 2321 db_iprintf(" sref=%d, backing_object(%d)=(%p)+0x%jx\n", 2322 object->shadow_count, 2323 object->backing_object ? object->backing_object->ref_count : 0, 2324 object->backing_object, (uintmax_t)object->backing_object_offset); 2325 2326 if (!full) 2327 return; 2328 2329 db_indent += 2; 2330 count = 0; 2331 TAILQ_FOREACH(p, &object->memq, listq) { 2332 if (count == 0) 2333 db_iprintf("memory:="); 2334 else if (count == 6) { 2335 db_printf("\n"); 2336 db_iprintf(" ..."); 2337 count = 0; 2338 } else 2339 db_printf(","); 2340 count++; 2341 2342 db_printf("(off=0x%jx,page=0x%jx)", 2343 (uintmax_t)p->pindex, (uintmax_t)VM_PAGE_TO_PHYS(p)); 2344 } 2345 if (count != 0) 2346 db_printf("\n"); 2347 db_indent -= 2; 2348 } 2349 2350 /* XXX. */ 2351 #undef count 2352 2353 /* XXX need this non-static entry for calling from vm_map_print. */ 2354 void 2355 vm_object_print( 2356 /* db_expr_t */ long addr, 2357 boolean_t have_addr, 2358 /* db_expr_t */ long count, 2359 char *modif) 2360 { 2361 vm_object_print_static(addr, have_addr, count, modif); 2362 } 2363 2364 DB_SHOW_COMMAND(vmopag, vm_object_print_pages) 2365 { 2366 vm_object_t object; 2367 vm_pindex_t fidx; 2368 vm_paddr_t pa; 2369 vm_page_t m, prev_m; 2370 int rcount, nl, c; 2371 2372 nl = 0; 2373 TAILQ_FOREACH(object, &vm_object_list, object_list) { 2374 db_printf("new object: %p\n", (void *)object); 2375 if (nl > 18) { 2376 c = cngetc(); 2377 if (c != ' ') 2378 return; 2379 nl = 0; 2380 } 2381 nl++; 2382 rcount = 0; 2383 fidx = 0; 2384 pa = -1; 2385 TAILQ_FOREACH(m, &object->memq, listq) { 2386 if (m->pindex > 128) 2387 break; 2388 if ((prev_m = TAILQ_PREV(m, pglist, listq)) != NULL && 2389 prev_m->pindex + 1 != m->pindex) { 2390 if (rcount) { 2391 db_printf(" index(%ld)run(%d)pa(0x%lx)\n", 2392 (long)fidx, rcount, (long)pa); 2393 if (nl > 18) { 2394 c = cngetc(); 2395 if (c != ' ') 2396 return; 2397 nl = 0; 2398 } 2399 nl++; 2400 rcount = 0; 2401 } 2402 } 2403 if (rcount && 2404 (VM_PAGE_TO_PHYS(m) == pa + rcount * PAGE_SIZE)) { 2405 ++rcount; 2406 continue; 2407 } 2408 if (rcount) { 2409 db_printf(" index(%ld)run(%d)pa(0x%lx)\n", 2410 (long)fidx, rcount, (long)pa); 2411 if (nl > 18) { 2412 c = cngetc(); 2413 if (c != ' ') 2414 return; 2415 nl = 0; 2416 } 2417 nl++; 2418 } 2419 fidx = m->pindex; 2420 pa = VM_PAGE_TO_PHYS(m); 2421 rcount = 1; 2422 } 2423 if (rcount) { 2424 db_printf(" index(%ld)run(%d)pa(0x%lx)\n", 2425 (long)fidx, rcount, (long)pa); 2426 if (nl > 18) { 2427 c = cngetc(); 2428 if (c != ' ') 2429 return; 2430 nl = 0; 2431 } 2432 nl++; 2433 } 2434 } 2435 } 2436 #endif /* DDB */ 2437