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/vnode.h> 82 #include <sys/vmmeter.h> 83 #include <sys/sx.h> 84 85 #include <vm/vm.h> 86 #include <vm/vm_param.h> 87 #include <vm/pmap.h> 88 #include <vm/vm_map.h> 89 #include <vm/vm_object.h> 90 #include <vm/vm_page.h> 91 #include <vm/vm_pageout.h> 92 #include <vm/vm_pager.h> 93 #include <vm/swap_pager.h> 94 #include <vm/vm_kern.h> 95 #include <vm/vm_extern.h> 96 #include <vm/vm_reserv.h> 97 #include <vm/uma.h> 98 99 static int old_msync; 100 SYSCTL_INT(_vm, OID_AUTO, old_msync, CTLFLAG_RW, &old_msync, 0, 101 "Use old (insecure) msync behavior"); 102 103 static int vm_object_page_collect_flush(vm_object_t object, vm_page_t p, 104 int pagerflags, int flags, boolean_t *clearobjflags, 105 boolean_t *eio); 106 static boolean_t vm_object_page_remove_write(vm_page_t p, int flags, 107 boolean_t *clearobjflags); 108 static void vm_object_qcollapse(vm_object_t object); 109 static void vm_object_vndeallocate(vm_object_t object); 110 111 /* 112 * Virtual memory objects maintain the actual data 113 * associated with allocated virtual memory. A given 114 * page of memory exists within exactly one object. 115 * 116 * An object is only deallocated when all "references" 117 * are given up. Only one "reference" to a given 118 * region of an object should be writeable. 119 * 120 * Associated with each object is a list of all resident 121 * memory pages belonging to that object; this list is 122 * maintained by the "vm_page" module, and locked by the object's 123 * lock. 124 * 125 * Each object also records a "pager" routine which is 126 * used to retrieve (and store) pages to the proper backing 127 * storage. In addition, objects may be backed by other 128 * objects from which they were virtual-copied. 129 * 130 * The only items within the object structure which are 131 * modified after time of creation are: 132 * reference count locked by object's lock 133 * pager routine locked by object's lock 134 * 135 */ 136 137 struct object_q vm_object_list; 138 struct mtx vm_object_list_mtx; /* lock for object list and count */ 139 140 struct vm_object kernel_object_store; 141 struct vm_object kmem_object_store; 142 143 static SYSCTL_NODE(_vm_stats, OID_AUTO, object, CTLFLAG_RD, 0, 144 "VM object stats"); 145 146 static long object_collapses; 147 SYSCTL_LONG(_vm_stats_object, OID_AUTO, collapses, CTLFLAG_RD, 148 &object_collapses, 0, "VM object collapses"); 149 150 static long object_bypasses; 151 SYSCTL_LONG(_vm_stats_object, OID_AUTO, bypasses, CTLFLAG_RD, 152 &object_bypasses, 0, "VM object bypasses"); 153 154 static uma_zone_t obj_zone; 155 156 static int vm_object_zinit(void *mem, int size, int flags); 157 158 #ifdef INVARIANTS 159 static void vm_object_zdtor(void *mem, int size, void *arg); 160 161 static void 162 vm_object_zdtor(void *mem, int size, void *arg) 163 { 164 vm_object_t object; 165 166 object = (vm_object_t)mem; 167 KASSERT(TAILQ_EMPTY(&object->memq), 168 ("object %p has resident pages", 169 object)); 170 #if VM_NRESERVLEVEL > 0 171 KASSERT(LIST_EMPTY(&object->rvq), 172 ("object %p has reservations", 173 object)); 174 #endif 175 KASSERT(object->cache == NULL, 176 ("object %p has cached pages", 177 object)); 178 KASSERT(object->paging_in_progress == 0, 179 ("object %p paging_in_progress = %d", 180 object, object->paging_in_progress)); 181 KASSERT(object->resident_page_count == 0, 182 ("object %p resident_page_count = %d", 183 object, object->resident_page_count)); 184 KASSERT(object->shadow_count == 0, 185 ("object %p shadow_count = %d", 186 object, object->shadow_count)); 187 } 188 #endif 189 190 static int 191 vm_object_zinit(void *mem, int size, int flags) 192 { 193 vm_object_t object; 194 195 object = (vm_object_t)mem; 196 bzero(&object->mtx, sizeof(object->mtx)); 197 VM_OBJECT_LOCK_INIT(object, "standard object"); 198 199 /* These are true for any object that has been freed */ 200 object->paging_in_progress = 0; 201 object->resident_page_count = 0; 202 object->shadow_count = 0; 203 return (0); 204 } 205 206 void 207 _vm_object_allocate(objtype_t type, vm_pindex_t size, vm_object_t object) 208 { 209 210 TAILQ_INIT(&object->memq); 211 LIST_INIT(&object->shadow_head); 212 213 object->root = NULL; 214 object->type = type; 215 object->size = size; 216 object->generation = 1; 217 object->ref_count = 1; 218 object->memattr = VM_MEMATTR_DEFAULT; 219 object->flags = 0; 220 object->cred = NULL; 221 object->charge = 0; 222 if ((object->type == OBJT_DEFAULT) || (object->type == OBJT_SWAP)) 223 object->flags = OBJ_ONEMAPPING; 224 object->pg_color = 0; 225 object->handle = NULL; 226 object->backing_object = NULL; 227 object->backing_object_offset = (vm_ooffset_t) 0; 228 #if VM_NRESERVLEVEL > 0 229 LIST_INIT(&object->rvq); 230 #endif 231 object->cache = NULL; 232 233 mtx_lock(&vm_object_list_mtx); 234 TAILQ_INSERT_TAIL(&vm_object_list, object, object_list); 235 mtx_unlock(&vm_object_list_mtx); 236 } 237 238 /* 239 * vm_object_init: 240 * 241 * Initialize the VM objects module. 242 */ 243 void 244 vm_object_init(void) 245 { 246 TAILQ_INIT(&vm_object_list); 247 mtx_init(&vm_object_list_mtx, "vm object_list", NULL, MTX_DEF); 248 249 VM_OBJECT_LOCK_INIT(kernel_object, "kernel object"); 250 _vm_object_allocate(OBJT_PHYS, OFF_TO_IDX(VM_MAX_KERNEL_ADDRESS - VM_MIN_KERNEL_ADDRESS), 251 kernel_object); 252 #if VM_NRESERVLEVEL > 0 253 kernel_object->flags |= OBJ_COLORED; 254 kernel_object->pg_color = (u_short)atop(VM_MIN_KERNEL_ADDRESS); 255 #endif 256 257 VM_OBJECT_LOCK_INIT(kmem_object, "kmem object"); 258 _vm_object_allocate(OBJT_PHYS, OFF_TO_IDX(VM_MAX_KERNEL_ADDRESS - VM_MIN_KERNEL_ADDRESS), 259 kmem_object); 260 #if VM_NRESERVLEVEL > 0 261 kmem_object->flags |= OBJ_COLORED; 262 kmem_object->pg_color = (u_short)atop(VM_MIN_KERNEL_ADDRESS); 263 #endif 264 265 /* 266 * The lock portion of struct vm_object must be type stable due 267 * to vm_pageout_fallback_object_lock locking a vm object 268 * without holding any references to it. 269 */ 270 obj_zone = uma_zcreate("VM OBJECT", sizeof (struct vm_object), NULL, 271 #ifdef INVARIANTS 272 vm_object_zdtor, 273 #else 274 NULL, 275 #endif 276 vm_object_zinit, NULL, UMA_ALIGN_PTR, UMA_ZONE_VM|UMA_ZONE_NOFREE); 277 } 278 279 void 280 vm_object_clear_flag(vm_object_t object, u_short bits) 281 { 282 283 VM_OBJECT_LOCK_ASSERT(object, MA_OWNED); 284 object->flags &= ~bits; 285 } 286 287 /* 288 * Sets the default memory attribute for the specified object. Pages 289 * that are allocated to this object are by default assigned this memory 290 * attribute. 291 * 292 * Presently, this function must be called before any pages are allocated 293 * to the object. In the future, this requirement may be relaxed for 294 * "default" and "swap" objects. 295 */ 296 int 297 vm_object_set_memattr(vm_object_t object, vm_memattr_t memattr) 298 { 299 300 VM_OBJECT_LOCK_ASSERT(object, MA_OWNED); 301 switch (object->type) { 302 case OBJT_DEFAULT: 303 case OBJT_DEVICE: 304 case OBJT_PHYS: 305 case OBJT_SG: 306 case OBJT_SWAP: 307 case OBJT_VNODE: 308 if (!TAILQ_EMPTY(&object->memq)) 309 return (KERN_FAILURE); 310 break; 311 case OBJT_DEAD: 312 return (KERN_INVALID_ARGUMENT); 313 } 314 object->memattr = memattr; 315 return (KERN_SUCCESS); 316 } 317 318 void 319 vm_object_pip_add(vm_object_t object, short i) 320 { 321 322 VM_OBJECT_LOCK_ASSERT(object, MA_OWNED); 323 object->paging_in_progress += i; 324 } 325 326 void 327 vm_object_pip_subtract(vm_object_t object, short i) 328 { 329 330 VM_OBJECT_LOCK_ASSERT(object, MA_OWNED); 331 object->paging_in_progress -= i; 332 } 333 334 void 335 vm_object_pip_wakeup(vm_object_t object) 336 { 337 338 VM_OBJECT_LOCK_ASSERT(object, MA_OWNED); 339 object->paging_in_progress--; 340 if ((object->flags & OBJ_PIPWNT) && object->paging_in_progress == 0) { 341 vm_object_clear_flag(object, OBJ_PIPWNT); 342 wakeup(object); 343 } 344 } 345 346 void 347 vm_object_pip_wakeupn(vm_object_t object, short i) 348 { 349 350 VM_OBJECT_LOCK_ASSERT(object, MA_OWNED); 351 if (i) 352 object->paging_in_progress -= i; 353 if ((object->flags & OBJ_PIPWNT) && object->paging_in_progress == 0) { 354 vm_object_clear_flag(object, OBJ_PIPWNT); 355 wakeup(object); 356 } 357 } 358 359 void 360 vm_object_pip_wait(vm_object_t object, char *waitid) 361 { 362 363 VM_OBJECT_LOCK_ASSERT(object, MA_OWNED); 364 while (object->paging_in_progress) { 365 object->flags |= OBJ_PIPWNT; 366 msleep(object, VM_OBJECT_MTX(object), PVM, waitid, 0); 367 } 368 } 369 370 /* 371 * vm_object_allocate: 372 * 373 * Returns a new object with the given size. 374 */ 375 vm_object_t 376 vm_object_allocate(objtype_t type, vm_pindex_t size) 377 { 378 vm_object_t object; 379 380 object = (vm_object_t)uma_zalloc(obj_zone, M_WAITOK); 381 _vm_object_allocate(type, size, object); 382 return (object); 383 } 384 385 386 /* 387 * vm_object_reference: 388 * 389 * Gets another reference to the given object. Note: OBJ_DEAD 390 * objects can be referenced during final cleaning. 391 */ 392 void 393 vm_object_reference(vm_object_t object) 394 { 395 if (object == NULL) 396 return; 397 VM_OBJECT_LOCK(object); 398 vm_object_reference_locked(object); 399 VM_OBJECT_UNLOCK(object); 400 } 401 402 /* 403 * vm_object_reference_locked: 404 * 405 * Gets another reference to the given object. 406 * 407 * The object must be locked. 408 */ 409 void 410 vm_object_reference_locked(vm_object_t object) 411 { 412 struct vnode *vp; 413 414 VM_OBJECT_LOCK_ASSERT(object, MA_OWNED); 415 object->ref_count++; 416 if (object->type == OBJT_VNODE) { 417 vp = object->handle; 418 vref(vp); 419 } 420 } 421 422 /* 423 * Handle deallocating an object of type OBJT_VNODE. 424 */ 425 static void 426 vm_object_vndeallocate(vm_object_t object) 427 { 428 struct vnode *vp = (struct vnode *) object->handle; 429 430 VFS_ASSERT_GIANT(vp->v_mount); 431 VM_OBJECT_LOCK_ASSERT(object, MA_OWNED); 432 KASSERT(object->type == OBJT_VNODE, 433 ("vm_object_vndeallocate: not a vnode object")); 434 KASSERT(vp != NULL, ("vm_object_vndeallocate: missing vp")); 435 #ifdef INVARIANTS 436 if (object->ref_count == 0) { 437 vprint("vm_object_vndeallocate", vp); 438 panic("vm_object_vndeallocate: bad object reference count"); 439 } 440 #endif 441 442 if (object->ref_count > 1) { 443 object->ref_count--; 444 VM_OBJECT_UNLOCK(object); 445 /* vrele may need the vnode lock. */ 446 vrele(vp); 447 } else { 448 vhold(vp); 449 VM_OBJECT_UNLOCK(object); 450 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY); 451 vdrop(vp); 452 VM_OBJECT_LOCK(object); 453 object->ref_count--; 454 if (object->type == OBJT_DEAD) { 455 VM_OBJECT_UNLOCK(object); 456 VOP_UNLOCK(vp, 0); 457 } else { 458 if (object->ref_count == 0) 459 VOP_UNSET_TEXT(vp); 460 VM_OBJECT_UNLOCK(object); 461 vput(vp); 462 } 463 } 464 } 465 466 /* 467 * vm_object_deallocate: 468 * 469 * Release a reference to the specified object, 470 * gained either through a vm_object_allocate 471 * or a vm_object_reference call. When all references 472 * are gone, storage associated with this object 473 * may be relinquished. 474 * 475 * No object may be locked. 476 */ 477 void 478 vm_object_deallocate(vm_object_t object) 479 { 480 vm_object_t temp; 481 482 while (object != NULL) { 483 int vfslocked; 484 485 vfslocked = 0; 486 restart: 487 VM_OBJECT_LOCK(object); 488 if (object->type == OBJT_VNODE) { 489 struct vnode *vp = (struct vnode *) object->handle; 490 491 /* 492 * Conditionally acquire Giant for a vnode-backed 493 * object. We have to be careful since the type of 494 * a vnode object can change while the object is 495 * unlocked. 496 */ 497 if (VFS_NEEDSGIANT(vp->v_mount) && !vfslocked) { 498 vfslocked = 1; 499 if (!mtx_trylock(&Giant)) { 500 VM_OBJECT_UNLOCK(object); 501 mtx_lock(&Giant); 502 goto restart; 503 } 504 } 505 vm_object_vndeallocate(object); 506 VFS_UNLOCK_GIANT(vfslocked); 507 return; 508 } else 509 /* 510 * This is to handle the case that the object 511 * changed type while we dropped its lock to 512 * obtain Giant. 513 */ 514 VFS_UNLOCK_GIANT(vfslocked); 515 516 KASSERT(object->ref_count != 0, 517 ("vm_object_deallocate: object deallocated too many times: %d", object->type)); 518 519 /* 520 * If the reference count goes to 0 we start calling 521 * vm_object_terminate() on the object chain. 522 * A ref count of 1 may be a special case depending on the 523 * shadow count being 0 or 1. 524 */ 525 object->ref_count--; 526 if (object->ref_count > 1) { 527 VM_OBJECT_UNLOCK(object); 528 return; 529 } else if (object->ref_count == 1) { 530 if (object->shadow_count == 0 && 531 object->handle == NULL && 532 (object->type == OBJT_DEFAULT || 533 object->type == OBJT_SWAP)) { 534 vm_object_set_flag(object, OBJ_ONEMAPPING); 535 } else if ((object->shadow_count == 1) && 536 (object->handle == NULL) && 537 (object->type == OBJT_DEFAULT || 538 object->type == OBJT_SWAP)) { 539 vm_object_t robject; 540 541 robject = LIST_FIRST(&object->shadow_head); 542 KASSERT(robject != NULL, 543 ("vm_object_deallocate: ref_count: %d, shadow_count: %d", 544 object->ref_count, 545 object->shadow_count)); 546 if (!VM_OBJECT_TRYLOCK(robject)) { 547 /* 548 * Avoid a potential deadlock. 549 */ 550 object->ref_count++; 551 VM_OBJECT_UNLOCK(object); 552 /* 553 * More likely than not the thread 554 * holding robject's lock has lower 555 * priority than the current thread. 556 * Let the lower priority thread run. 557 */ 558 pause("vmo_de", 1); 559 continue; 560 } 561 /* 562 * Collapse object into its shadow unless its 563 * shadow is dead. In that case, object will 564 * be deallocated by the thread that is 565 * deallocating its shadow. 566 */ 567 if ((robject->flags & OBJ_DEAD) == 0 && 568 (robject->handle == NULL) && 569 (robject->type == OBJT_DEFAULT || 570 robject->type == OBJT_SWAP)) { 571 572 robject->ref_count++; 573 retry: 574 if (robject->paging_in_progress) { 575 VM_OBJECT_UNLOCK(object); 576 vm_object_pip_wait(robject, 577 "objde1"); 578 temp = robject->backing_object; 579 if (object == temp) { 580 VM_OBJECT_LOCK(object); 581 goto retry; 582 } 583 } else if (object->paging_in_progress) { 584 VM_OBJECT_UNLOCK(robject); 585 object->flags |= OBJ_PIPWNT; 586 msleep(object, 587 VM_OBJECT_MTX(object), 588 PDROP | PVM, "objde2", 0); 589 VM_OBJECT_LOCK(robject); 590 temp = robject->backing_object; 591 if (object == temp) { 592 VM_OBJECT_LOCK(object); 593 goto retry; 594 } 595 } else 596 VM_OBJECT_UNLOCK(object); 597 598 if (robject->ref_count == 1) { 599 robject->ref_count--; 600 object = robject; 601 goto doterm; 602 } 603 object = robject; 604 vm_object_collapse(object); 605 VM_OBJECT_UNLOCK(object); 606 continue; 607 } 608 VM_OBJECT_UNLOCK(robject); 609 } 610 VM_OBJECT_UNLOCK(object); 611 return; 612 } 613 doterm: 614 temp = object->backing_object; 615 if (temp != NULL) { 616 VM_OBJECT_LOCK(temp); 617 LIST_REMOVE(object, shadow_list); 618 temp->shadow_count--; 619 VM_OBJECT_UNLOCK(temp); 620 object->backing_object = NULL; 621 } 622 /* 623 * Don't double-terminate, we could be in a termination 624 * recursion due to the terminate having to sync data 625 * to disk. 626 */ 627 if ((object->flags & OBJ_DEAD) == 0) 628 vm_object_terminate(object); 629 else 630 VM_OBJECT_UNLOCK(object); 631 object = temp; 632 } 633 } 634 635 /* 636 * vm_object_destroy removes the object from the global object list 637 * and frees the space for the object. 638 */ 639 void 640 vm_object_destroy(vm_object_t object) 641 { 642 643 /* 644 * Remove the object from the global object list. 645 */ 646 mtx_lock(&vm_object_list_mtx); 647 TAILQ_REMOVE(&vm_object_list, object, object_list); 648 mtx_unlock(&vm_object_list_mtx); 649 650 /* 651 * Release the allocation charge. 652 */ 653 if (object->cred != NULL) { 654 KASSERT(object->type == OBJT_DEFAULT || 655 object->type == OBJT_SWAP, 656 ("vm_object_terminate: non-swap obj %p has cred", 657 object)); 658 swap_release_by_cred(object->charge, object->cred); 659 object->charge = 0; 660 crfree(object->cred); 661 object->cred = NULL; 662 } 663 664 /* 665 * Free the space for the object. 666 */ 667 uma_zfree(obj_zone, object); 668 } 669 670 /* 671 * vm_object_terminate actually destroys the specified object, freeing 672 * up all previously used resources. 673 * 674 * The object must be locked. 675 * This routine may block. 676 */ 677 void 678 vm_object_terminate(vm_object_t object) 679 { 680 vm_page_t p, p_next; 681 682 VM_OBJECT_LOCK_ASSERT(object, MA_OWNED); 683 684 /* 685 * Make sure no one uses us. 686 */ 687 vm_object_set_flag(object, OBJ_DEAD); 688 689 /* 690 * wait for the pageout daemon to be done with the object 691 */ 692 vm_object_pip_wait(object, "objtrm"); 693 694 KASSERT(!object->paging_in_progress, 695 ("vm_object_terminate: pageout in progress")); 696 697 /* 698 * Clean and free the pages, as appropriate. All references to the 699 * object are gone, so we don't need to lock it. 700 */ 701 if (object->type == OBJT_VNODE) { 702 struct vnode *vp = (struct vnode *)object->handle; 703 704 /* 705 * Clean pages and flush buffers. 706 */ 707 vm_object_page_clean(object, 0, 0, OBJPC_SYNC); 708 VM_OBJECT_UNLOCK(object); 709 710 vinvalbuf(vp, V_SAVE, 0, 0); 711 712 VM_OBJECT_LOCK(object); 713 } 714 715 KASSERT(object->ref_count == 0, 716 ("vm_object_terminate: object with references, ref_count=%d", 717 object->ref_count)); 718 719 /* 720 * Free any remaining pageable pages. This also removes them from the 721 * paging queues. However, don't free wired pages, just remove them 722 * from the object. Rather than incrementally removing each page from 723 * the object, the page and object are reset to any empty state. 724 */ 725 TAILQ_FOREACH_SAFE(p, &object->memq, listq, p_next) { 726 KASSERT(!p->busy && (p->oflags & VPO_BUSY) == 0, 727 ("vm_object_terminate: freeing busy page %p", p)); 728 vm_page_lock(p); 729 /* 730 * Optimize the page's removal from the object by resetting 731 * its "object" field. Specifically, if the page is not 732 * wired, then the effect of this assignment is that 733 * vm_page_free()'s call to vm_page_remove() will return 734 * immediately without modifying the page or the object. 735 */ 736 p->object = NULL; 737 if (p->wire_count == 0) { 738 vm_page_free(p); 739 PCPU_INC(cnt.v_pfree); 740 } 741 vm_page_unlock(p); 742 } 743 /* 744 * If the object contained any pages, then reset it to an empty state. 745 * None of the object's fields, including "resident_page_count", were 746 * modified by the preceding loop. 747 */ 748 if (object->resident_page_count != 0) { 749 object->root = NULL; 750 TAILQ_INIT(&object->memq); 751 object->resident_page_count = 0; 752 if (object->type == OBJT_VNODE) 753 vdrop(object->handle); 754 } 755 756 #if VM_NRESERVLEVEL > 0 757 if (__predict_false(!LIST_EMPTY(&object->rvq))) 758 vm_reserv_break_all(object); 759 #endif 760 if (__predict_false(object->cache != NULL)) 761 vm_page_cache_free(object, 0, 0); 762 763 /* 764 * Let the pager know object is dead. 765 */ 766 vm_pager_deallocate(object); 767 VM_OBJECT_UNLOCK(object); 768 769 vm_object_destroy(object); 770 } 771 772 /* 773 * Make the page read-only so that we can clear the object flags. However, if 774 * this is a nosync mmap then the object is likely to stay dirty so do not 775 * mess with the page and do not clear the object flags. Returns TRUE if the 776 * page should be flushed, and FALSE otherwise. 777 */ 778 static boolean_t 779 vm_object_page_remove_write(vm_page_t p, int flags, boolean_t *clearobjflags) 780 { 781 782 /* 783 * If we have been asked to skip nosync pages and this is a 784 * nosync page, skip it. Note that the object flags were not 785 * cleared in this case so we do not have to set them. 786 */ 787 if ((flags & OBJPC_NOSYNC) != 0 && (p->oflags & VPO_NOSYNC) != 0) { 788 *clearobjflags = FALSE; 789 return (FALSE); 790 } else { 791 pmap_remove_write(p); 792 return (p->dirty != 0); 793 } 794 } 795 796 /* 797 * vm_object_page_clean 798 * 799 * Clean all dirty pages in the specified range of object. Leaves page 800 * on whatever queue it is currently on. If NOSYNC is set then do not 801 * write out pages with VPO_NOSYNC set (originally comes from MAP_NOSYNC), 802 * leaving the object dirty. 803 * 804 * When stuffing pages asynchronously, allow clustering. XXX we need a 805 * synchronous clustering mode implementation. 806 * 807 * Odd semantics: if start == end, we clean everything. 808 * 809 * The object must be locked. 810 * 811 * Returns FALSE if some page from the range was not written, as 812 * reported by the pager, and TRUE otherwise. 813 */ 814 boolean_t 815 vm_object_page_clean(vm_object_t object, vm_ooffset_t start, vm_ooffset_t end, 816 int flags) 817 { 818 vm_page_t np, p; 819 vm_pindex_t pi, tend, tstart; 820 int curgeneration, n, pagerflags; 821 boolean_t clearobjflags, eio, res; 822 823 mtx_assert(&vm_page_queue_mtx, MA_NOTOWNED); 824 VM_OBJECT_LOCK_ASSERT(object, MA_OWNED); 825 KASSERT(object->type == OBJT_VNODE, ("Not a vnode object")); 826 if ((object->flags & OBJ_MIGHTBEDIRTY) == 0 || 827 object->resident_page_count == 0) 828 return (TRUE); 829 830 pagerflags = (flags & (OBJPC_SYNC | OBJPC_INVAL)) != 0 ? 831 VM_PAGER_PUT_SYNC : VM_PAGER_CLUSTER_OK; 832 pagerflags |= (flags & OBJPC_INVAL) != 0 ? VM_PAGER_PUT_INVAL : 0; 833 834 tstart = OFF_TO_IDX(start); 835 tend = (end == 0) ? object->size : OFF_TO_IDX(end + PAGE_MASK); 836 clearobjflags = tstart == 0 && tend >= object->size; 837 res = TRUE; 838 839 rescan: 840 curgeneration = object->generation; 841 842 for (p = vm_page_find_least(object, tstart); p != NULL; p = np) { 843 pi = p->pindex; 844 if (pi >= tend) 845 break; 846 np = TAILQ_NEXT(p, listq); 847 if (p->valid == 0) 848 continue; 849 if (vm_page_sleep_if_busy(p, TRUE, "vpcwai")) { 850 if (object->generation != curgeneration) { 851 if ((flags & OBJPC_SYNC) != 0) 852 goto rescan; 853 else 854 clearobjflags = FALSE; 855 } 856 np = vm_page_find_least(object, pi); 857 continue; 858 } 859 if (!vm_object_page_remove_write(p, flags, &clearobjflags)) 860 continue; 861 862 n = vm_object_page_collect_flush(object, p, pagerflags, 863 flags, &clearobjflags, &eio); 864 if (eio) { 865 res = FALSE; 866 clearobjflags = FALSE; 867 } 868 if (object->generation != curgeneration) { 869 if ((flags & OBJPC_SYNC) != 0) 870 goto rescan; 871 else 872 clearobjflags = FALSE; 873 } 874 875 /* 876 * If the VOP_PUTPAGES() did a truncated write, so 877 * that even the first page of the run is not fully 878 * written, vm_pageout_flush() returns 0 as the run 879 * length. Since the condition that caused truncated 880 * write may be permanent, e.g. exhausted free space, 881 * accepting n == 0 would cause an infinite loop. 882 * 883 * Forwarding the iterator leaves the unwritten page 884 * behind, but there is not much we can do there if 885 * filesystem refuses to write it. 886 */ 887 if (n == 0) { 888 n = 1; 889 clearobjflags = FALSE; 890 } 891 np = vm_page_find_least(object, pi + n); 892 } 893 #if 0 894 VOP_FSYNC(vp, (pagerflags & VM_PAGER_PUT_SYNC) ? MNT_WAIT : 0); 895 #endif 896 897 if (clearobjflags) 898 vm_object_clear_flag(object, OBJ_MIGHTBEDIRTY); 899 return (res); 900 } 901 902 static int 903 vm_object_page_collect_flush(vm_object_t object, vm_page_t p, int pagerflags, 904 int flags, boolean_t *clearobjflags, boolean_t *eio) 905 { 906 vm_page_t ma[vm_pageout_page_count], p_first, tp; 907 int count, i, mreq, runlen; 908 909 mtx_assert(&vm_page_queue_mtx, MA_NOTOWNED); 910 vm_page_lock_assert(p, MA_NOTOWNED); 911 VM_OBJECT_LOCK_ASSERT(object, MA_OWNED); 912 913 count = 1; 914 mreq = 0; 915 916 for (tp = p; count < vm_pageout_page_count; count++) { 917 tp = vm_page_next(tp); 918 if (tp == NULL || tp->busy != 0 || (tp->oflags & VPO_BUSY) != 0) 919 break; 920 if (!vm_object_page_remove_write(tp, flags, clearobjflags)) 921 break; 922 } 923 924 for (p_first = p; count < vm_pageout_page_count; count++) { 925 tp = vm_page_prev(p_first); 926 if (tp == NULL || tp->busy != 0 || (tp->oflags & VPO_BUSY) != 0) 927 break; 928 if (!vm_object_page_remove_write(tp, flags, clearobjflags)) 929 break; 930 p_first = tp; 931 mreq++; 932 } 933 934 for (tp = p_first, i = 0; i < count; tp = TAILQ_NEXT(tp, listq), i++) 935 ma[i] = tp; 936 937 vm_pageout_flush(ma, count, pagerflags, mreq, &runlen, eio); 938 return (runlen); 939 } 940 941 /* 942 * Note that there is absolutely no sense in writing out 943 * anonymous objects, so we track down the vnode object 944 * to write out. 945 * We invalidate (remove) all pages from the address space 946 * for semantic correctness. 947 * 948 * If the backing object is a device object with unmanaged pages, then any 949 * mappings to the specified range of pages must be removed before this 950 * function is called. 951 * 952 * Note: certain anonymous maps, such as MAP_NOSYNC maps, 953 * may start out with a NULL object. 954 */ 955 boolean_t 956 vm_object_sync(vm_object_t object, vm_ooffset_t offset, vm_size_t size, 957 boolean_t syncio, boolean_t invalidate) 958 { 959 vm_object_t backing_object; 960 struct vnode *vp; 961 struct mount *mp; 962 int error, flags, fsync_after; 963 boolean_t res; 964 965 if (object == NULL) 966 return (TRUE); 967 res = TRUE; 968 error = 0; 969 VM_OBJECT_LOCK(object); 970 while ((backing_object = object->backing_object) != NULL) { 971 VM_OBJECT_LOCK(backing_object); 972 offset += object->backing_object_offset; 973 VM_OBJECT_UNLOCK(object); 974 object = backing_object; 975 if (object->size < OFF_TO_IDX(offset + size)) 976 size = IDX_TO_OFF(object->size) - offset; 977 } 978 /* 979 * Flush pages if writing is allowed, invalidate them 980 * if invalidation requested. Pages undergoing I/O 981 * will be ignored by vm_object_page_remove(). 982 * 983 * We cannot lock the vnode and then wait for paging 984 * to complete without deadlocking against vm_fault. 985 * Instead we simply call vm_object_page_remove() and 986 * allow it to block internally on a page-by-page 987 * basis when it encounters pages undergoing async 988 * I/O. 989 */ 990 if (object->type == OBJT_VNODE && 991 (object->flags & OBJ_MIGHTBEDIRTY) != 0) { 992 int vfslocked; 993 vp = object->handle; 994 VM_OBJECT_UNLOCK(object); 995 (void) vn_start_write(vp, &mp, V_WAIT); 996 vfslocked = VFS_LOCK_GIANT(vp->v_mount); 997 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY); 998 if (syncio && !invalidate && offset == 0 && 999 OFF_TO_IDX(size) == object->size) { 1000 /* 1001 * If syncing the whole mapping of the file, 1002 * it is faster to schedule all the writes in 1003 * async mode, also allowing the clustering, 1004 * and then wait for i/o to complete. 1005 */ 1006 flags = 0; 1007 fsync_after = TRUE; 1008 } else { 1009 flags = (syncio || invalidate) ? OBJPC_SYNC : 0; 1010 flags |= invalidate ? (OBJPC_SYNC | OBJPC_INVAL) : 0; 1011 fsync_after = FALSE; 1012 } 1013 VM_OBJECT_LOCK(object); 1014 res = vm_object_page_clean(object, offset, offset + size, 1015 flags); 1016 VM_OBJECT_UNLOCK(object); 1017 if (fsync_after) 1018 error = VOP_FSYNC(vp, MNT_WAIT, curthread); 1019 VOP_UNLOCK(vp, 0); 1020 VFS_UNLOCK_GIANT(vfslocked); 1021 vn_finished_write(mp); 1022 if (error != 0) 1023 res = FALSE; 1024 VM_OBJECT_LOCK(object); 1025 } 1026 if ((object->type == OBJT_VNODE || 1027 object->type == OBJT_DEVICE) && invalidate) { 1028 if (object->type == OBJT_DEVICE) 1029 /* 1030 * The option OBJPR_NOTMAPPED must be passed here 1031 * because vm_object_page_remove() cannot remove 1032 * unmanaged mappings. 1033 */ 1034 flags = OBJPR_NOTMAPPED; 1035 else if (old_msync) 1036 flags = 0; 1037 else 1038 flags = OBJPR_CLEANONLY; 1039 vm_object_page_remove(object, OFF_TO_IDX(offset), 1040 OFF_TO_IDX(offset + size + PAGE_MASK), flags); 1041 } 1042 VM_OBJECT_UNLOCK(object); 1043 return (res); 1044 } 1045 1046 /* 1047 * vm_object_madvise: 1048 * 1049 * Implements the madvise function at the object/page level. 1050 * 1051 * MADV_WILLNEED (any object) 1052 * 1053 * Activate the specified pages if they are resident. 1054 * 1055 * MADV_DONTNEED (any object) 1056 * 1057 * Deactivate the specified pages if they are resident. 1058 * 1059 * MADV_FREE (OBJT_DEFAULT/OBJT_SWAP objects, 1060 * OBJ_ONEMAPPING only) 1061 * 1062 * Deactivate and clean the specified pages if they are 1063 * resident. This permits the process to reuse the pages 1064 * without faulting or the kernel to reclaim the pages 1065 * without I/O. 1066 */ 1067 void 1068 vm_object_madvise(vm_object_t object, vm_pindex_t pindex, vm_pindex_t end, 1069 int advise) 1070 { 1071 vm_pindex_t tpindex; 1072 vm_object_t backing_object, tobject; 1073 vm_page_t m; 1074 1075 if (object == NULL) 1076 return; 1077 VM_OBJECT_LOCK(object); 1078 /* 1079 * Locate and adjust resident pages 1080 */ 1081 for (; pindex < end; pindex += 1) { 1082 relookup: 1083 tobject = object; 1084 tpindex = pindex; 1085 shadowlookup: 1086 /* 1087 * MADV_FREE only operates on OBJT_DEFAULT or OBJT_SWAP pages 1088 * and those pages must be OBJ_ONEMAPPING. 1089 */ 1090 if (advise == MADV_FREE) { 1091 if ((tobject->type != OBJT_DEFAULT && 1092 tobject->type != OBJT_SWAP) || 1093 (tobject->flags & OBJ_ONEMAPPING) == 0) { 1094 goto unlock_tobject; 1095 } 1096 } else if (tobject->type == OBJT_PHYS) 1097 goto unlock_tobject; 1098 m = vm_page_lookup(tobject, tpindex); 1099 if (m == NULL && advise == MADV_WILLNEED) { 1100 /* 1101 * If the page is cached, reactivate it. 1102 */ 1103 m = vm_page_alloc(tobject, tpindex, VM_ALLOC_IFCACHED | 1104 VM_ALLOC_NOBUSY); 1105 } 1106 if (m == NULL) { 1107 /* 1108 * There may be swap even if there is no backing page 1109 */ 1110 if (advise == MADV_FREE && tobject->type == OBJT_SWAP) 1111 swap_pager_freespace(tobject, tpindex, 1); 1112 /* 1113 * next object 1114 */ 1115 backing_object = tobject->backing_object; 1116 if (backing_object == NULL) 1117 goto unlock_tobject; 1118 VM_OBJECT_LOCK(backing_object); 1119 tpindex += OFF_TO_IDX(tobject->backing_object_offset); 1120 if (tobject != object) 1121 VM_OBJECT_UNLOCK(tobject); 1122 tobject = backing_object; 1123 goto shadowlookup; 1124 } else if (m->valid != VM_PAGE_BITS_ALL) 1125 goto unlock_tobject; 1126 /* 1127 * If the page is not in a normal state, skip it. 1128 */ 1129 vm_page_lock(m); 1130 if (m->hold_count != 0 || m->wire_count != 0) { 1131 vm_page_unlock(m); 1132 goto unlock_tobject; 1133 } 1134 KASSERT((m->flags & PG_FICTITIOUS) == 0, 1135 ("vm_object_madvise: page %p is fictitious", m)); 1136 KASSERT((m->oflags & VPO_UNMANAGED) == 0, 1137 ("vm_object_madvise: page %p is not managed", m)); 1138 if ((m->oflags & VPO_BUSY) || m->busy) { 1139 if (advise == MADV_WILLNEED) { 1140 /* 1141 * Reference the page before unlocking and 1142 * sleeping so that the page daemon is less 1143 * likely to reclaim it. 1144 */ 1145 vm_page_aflag_set(m, PGA_REFERENCED); 1146 } 1147 vm_page_unlock(m); 1148 if (object != tobject) 1149 VM_OBJECT_UNLOCK(object); 1150 m->oflags |= VPO_WANTED; 1151 msleep(m, VM_OBJECT_MTX(tobject), PDROP | PVM, "madvpo", 1152 0); 1153 VM_OBJECT_LOCK(object); 1154 goto relookup; 1155 } 1156 if (advise == MADV_WILLNEED) { 1157 vm_page_activate(m); 1158 } else if (advise == MADV_DONTNEED) { 1159 vm_page_dontneed(m); 1160 } else if (advise == MADV_FREE) { 1161 /* 1162 * Mark the page clean. This will allow the page 1163 * to be freed up by the system. However, such pages 1164 * are often reused quickly by malloc()/free() 1165 * so we do not do anything that would cause 1166 * a page fault if we can help it. 1167 * 1168 * Specifically, we do not try to actually free 1169 * the page now nor do we try to put it in the 1170 * cache (which would cause a page fault on reuse). 1171 * 1172 * But we do make the page is freeable as we 1173 * can without actually taking the step of unmapping 1174 * it. 1175 */ 1176 pmap_clear_modify(m); 1177 m->dirty = 0; 1178 m->act_count = 0; 1179 vm_page_dontneed(m); 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_UNLOCK(tobject); 1187 } 1188 VM_OBJECT_UNLOCK(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_LOCK(source); 1217 if (source->ref_count == 1 && 1218 source->handle == NULL && 1219 (source->type == OBJT_DEFAULT || 1220 source->type == OBJT_SWAP)) { 1221 VM_OBJECT_UNLOCK(source); 1222 return; 1223 } 1224 VM_OBJECT_UNLOCK(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_LOCK(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_UNLOCK(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_UNLOCK(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_LOCK(new_object); 1304 VM_OBJECT_LOCK(orig_object); 1305 source = orig_object->backing_object; 1306 if (source != NULL) { 1307 VM_OBJECT_LOCK(source); 1308 if ((source->flags & OBJ_DEAD) != 0) { 1309 VM_OBJECT_UNLOCK(source); 1310 VM_OBJECT_UNLOCK(orig_object); 1311 VM_OBJECT_UNLOCK(new_object); 1312 vm_object_deallocate(new_object); 1313 VM_OBJECT_LOCK(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_UNLOCK(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 ((m->oflags & VPO_BUSY) || m->busy) { 1348 VM_OBJECT_UNLOCK(new_object); 1349 m->oflags |= VPO_WANTED; 1350 msleep(m, VM_OBJECT_MTX(orig_object), PVM, "spltwt", 0); 1351 VM_OBJECT_LOCK(new_object); 1352 goto retry; 1353 } 1354 #if VM_NRESERVLEVEL > 0 1355 /* 1356 * If some of the reservation's allocated pages remain with 1357 * the original object, then transferring the reservation to 1358 * the new object is neither particularly beneficial nor 1359 * particularly harmful as compared to leaving the reservation 1360 * with the original object. If, however, all of the 1361 * reservation's allocated pages are transferred to the new 1362 * object, then transferring the reservation is typically 1363 * beneficial. Determining which of these two cases applies 1364 * would be more costly than unconditionally renaming the 1365 * reservation. 1366 */ 1367 vm_reserv_rename(m, new_object, orig_object, offidxstart); 1368 #endif 1369 vm_page_lock(m); 1370 vm_page_rename(m, new_object, idx); 1371 vm_page_unlock(m); 1372 /* page automatically made dirty by rename and cache handled */ 1373 vm_page_busy(m); 1374 } 1375 if (orig_object->type == OBJT_SWAP) { 1376 /* 1377 * swap_pager_copy() can sleep, in which case the orig_object's 1378 * and new_object's locks are released and reacquired. 1379 */ 1380 swap_pager_copy(orig_object, new_object, offidxstart, 0); 1381 1382 /* 1383 * Transfer any cached pages from orig_object to new_object. 1384 * If swap_pager_copy() found swapped out pages within the 1385 * specified range of orig_object, then it changed 1386 * new_object's type to OBJT_SWAP when it transferred those 1387 * pages to new_object. Otherwise, new_object's type 1388 * should still be OBJT_DEFAULT and orig_object should not 1389 * contain any cached pages within the specified range. 1390 */ 1391 if (__predict_false(orig_object->cache != NULL)) 1392 vm_page_cache_transfer(orig_object, offidxstart, 1393 new_object); 1394 } 1395 VM_OBJECT_UNLOCK(orig_object); 1396 TAILQ_FOREACH(m, &new_object->memq, listq) 1397 vm_page_wakeup(m); 1398 VM_OBJECT_UNLOCK(new_object); 1399 entry->object.vm_object = new_object; 1400 entry->offset = 0LL; 1401 vm_object_deallocate(orig_object); 1402 VM_OBJECT_LOCK(new_object); 1403 } 1404 1405 #define OBSC_TEST_ALL_SHADOWED 0x0001 1406 #define OBSC_COLLAPSE_NOWAIT 0x0002 1407 #define OBSC_COLLAPSE_WAIT 0x0004 1408 1409 static int 1410 vm_object_backing_scan(vm_object_t object, int op) 1411 { 1412 int r = 1; 1413 vm_page_t p; 1414 vm_object_t backing_object; 1415 vm_pindex_t backing_offset_index; 1416 1417 VM_OBJECT_LOCK_ASSERT(object, MA_OWNED); 1418 VM_OBJECT_LOCK_ASSERT(object->backing_object, MA_OWNED); 1419 1420 backing_object = object->backing_object; 1421 backing_offset_index = OFF_TO_IDX(object->backing_object_offset); 1422 1423 /* 1424 * Initial conditions 1425 */ 1426 if (op & OBSC_TEST_ALL_SHADOWED) { 1427 /* 1428 * We do not want to have to test for the existence of cache 1429 * or swap pages in the backing object. XXX but with the 1430 * new swapper this would be pretty easy to do. 1431 * 1432 * XXX what about anonymous MAP_SHARED memory that hasn't 1433 * been ZFOD faulted yet? If we do not test for this, the 1434 * shadow test may succeed! XXX 1435 */ 1436 if (backing_object->type != OBJT_DEFAULT) { 1437 return (0); 1438 } 1439 } 1440 if (op & OBSC_COLLAPSE_WAIT) { 1441 vm_object_set_flag(backing_object, OBJ_DEAD); 1442 } 1443 1444 /* 1445 * Our scan 1446 */ 1447 p = TAILQ_FIRST(&backing_object->memq); 1448 while (p) { 1449 vm_page_t next = TAILQ_NEXT(p, listq); 1450 vm_pindex_t new_pindex = p->pindex - backing_offset_index; 1451 1452 if (op & OBSC_TEST_ALL_SHADOWED) { 1453 vm_page_t pp; 1454 1455 /* 1456 * Ignore pages outside the parent object's range 1457 * and outside the parent object's mapping of the 1458 * backing object. 1459 * 1460 * note that we do not busy the backing object's 1461 * page. 1462 */ 1463 if ( 1464 p->pindex < backing_offset_index || 1465 new_pindex >= object->size 1466 ) { 1467 p = next; 1468 continue; 1469 } 1470 1471 /* 1472 * See if the parent has the page or if the parent's 1473 * object pager has the page. If the parent has the 1474 * page but the page is not valid, the parent's 1475 * object pager must have the page. 1476 * 1477 * If this fails, the parent does not completely shadow 1478 * the object and we might as well give up now. 1479 */ 1480 1481 pp = vm_page_lookup(object, new_pindex); 1482 if ( 1483 (pp == NULL || pp->valid == 0) && 1484 !vm_pager_has_page(object, new_pindex, NULL, NULL) 1485 ) { 1486 r = 0; 1487 break; 1488 } 1489 } 1490 1491 /* 1492 * Check for busy page 1493 */ 1494 if (op & (OBSC_COLLAPSE_WAIT | OBSC_COLLAPSE_NOWAIT)) { 1495 vm_page_t pp; 1496 1497 if (op & OBSC_COLLAPSE_NOWAIT) { 1498 if ((p->oflags & VPO_BUSY) || 1499 !p->valid || 1500 p->busy) { 1501 p = next; 1502 continue; 1503 } 1504 } else if (op & OBSC_COLLAPSE_WAIT) { 1505 if ((p->oflags & VPO_BUSY) || p->busy) { 1506 VM_OBJECT_UNLOCK(object); 1507 p->oflags |= VPO_WANTED; 1508 msleep(p, VM_OBJECT_MTX(backing_object), 1509 PDROP | PVM, "vmocol", 0); 1510 VM_OBJECT_LOCK(object); 1511 VM_OBJECT_LOCK(backing_object); 1512 /* 1513 * If we slept, anything could have 1514 * happened. Since the object is 1515 * marked dead, the backing offset 1516 * should not have changed so we 1517 * just restart our scan. 1518 */ 1519 p = TAILQ_FIRST(&backing_object->memq); 1520 continue; 1521 } 1522 } 1523 1524 KASSERT( 1525 p->object == backing_object, 1526 ("vm_object_backing_scan: object mismatch") 1527 ); 1528 1529 /* 1530 * Destroy any associated swap 1531 */ 1532 if (backing_object->type == OBJT_SWAP) { 1533 swap_pager_freespace( 1534 backing_object, 1535 p->pindex, 1536 1 1537 ); 1538 } 1539 1540 if ( 1541 p->pindex < backing_offset_index || 1542 new_pindex >= object->size 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 /* 1566 * The page in the parent is not (yet) valid. 1567 * We don't know anything about the state of 1568 * the original page. It might be mapped, 1569 * so we must avoid the next if here. 1570 * 1571 * This is due to a race in vm_fault() where 1572 * we must unbusy the original (backing_obj) 1573 * page before we can (re)lock the parent. 1574 * Hence we can get here. 1575 */ 1576 p = next; 1577 continue; 1578 } 1579 if ( 1580 pp != NULL || 1581 vm_pager_has_page(object, new_pindex, NULL, NULL) 1582 ) { 1583 /* 1584 * page already exists in parent OR swap exists 1585 * for this location in the parent. Destroy 1586 * the original page from the backing object. 1587 * 1588 * Leave the parent's page alone 1589 */ 1590 vm_page_lock(p); 1591 KASSERT(!pmap_page_is_mapped(p), 1592 ("freeing mapped page %p", p)); 1593 if (p->wire_count == 0) 1594 vm_page_free(p); 1595 else 1596 vm_page_remove(p); 1597 vm_page_unlock(p); 1598 p = next; 1599 continue; 1600 } 1601 1602 #if VM_NRESERVLEVEL > 0 1603 /* 1604 * Rename the reservation. 1605 */ 1606 vm_reserv_rename(p, object, backing_object, 1607 backing_offset_index); 1608 #endif 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 */ 1617 vm_page_lock(p); 1618 vm_page_rename(p, object, new_pindex); 1619 vm_page_unlock(p); 1620 /* page automatically made dirty by rename */ 1621 } 1622 p = next; 1623 } 1624 return (r); 1625 } 1626 1627 1628 /* 1629 * this version of collapse allows the operation to occur earlier and 1630 * when paging_in_progress is true for an object... This is not a complete 1631 * operation, but should plug 99.9% of the rest of the leaks. 1632 */ 1633 static void 1634 vm_object_qcollapse(vm_object_t object) 1635 { 1636 vm_object_t backing_object = object->backing_object; 1637 1638 VM_OBJECT_LOCK_ASSERT(object, MA_OWNED); 1639 VM_OBJECT_LOCK_ASSERT(backing_object, MA_OWNED); 1640 1641 if (backing_object->ref_count != 1) 1642 return; 1643 1644 vm_object_backing_scan(object, OBSC_COLLAPSE_NOWAIT); 1645 } 1646 1647 /* 1648 * vm_object_collapse: 1649 * 1650 * Collapse an object with the object backing it. 1651 * Pages in the backing object are moved into the 1652 * parent, and the backing object is deallocated. 1653 */ 1654 void 1655 vm_object_collapse(vm_object_t object) 1656 { 1657 VM_OBJECT_LOCK_ASSERT(object, MA_OWNED); 1658 1659 while (TRUE) { 1660 vm_object_t backing_object; 1661 1662 /* 1663 * Verify that the conditions are right for collapse: 1664 * 1665 * The object exists and the backing object exists. 1666 */ 1667 if ((backing_object = object->backing_object) == NULL) 1668 break; 1669 1670 /* 1671 * we check the backing object first, because it is most likely 1672 * not collapsable. 1673 */ 1674 VM_OBJECT_LOCK(backing_object); 1675 if (backing_object->handle != NULL || 1676 (backing_object->type != OBJT_DEFAULT && 1677 backing_object->type != OBJT_SWAP) || 1678 (backing_object->flags & OBJ_DEAD) || 1679 object->handle != NULL || 1680 (object->type != OBJT_DEFAULT && 1681 object->type != OBJT_SWAP) || 1682 (object->flags & OBJ_DEAD)) { 1683 VM_OBJECT_UNLOCK(backing_object); 1684 break; 1685 } 1686 1687 if ( 1688 object->paging_in_progress != 0 || 1689 backing_object->paging_in_progress != 0 1690 ) { 1691 vm_object_qcollapse(object); 1692 VM_OBJECT_UNLOCK(backing_object); 1693 break; 1694 } 1695 /* 1696 * We know that we can either collapse the backing object (if 1697 * the parent is the only reference to it) or (perhaps) have 1698 * the parent bypass the object if the parent happens to shadow 1699 * all the resident pages in the entire backing object. 1700 * 1701 * This is ignoring pager-backed pages such as swap pages. 1702 * vm_object_backing_scan fails the shadowing test in this 1703 * case. 1704 */ 1705 if (backing_object->ref_count == 1) { 1706 /* 1707 * If there is exactly one reference to the backing 1708 * object, we can collapse it into the parent. 1709 */ 1710 vm_object_backing_scan(object, OBSC_COLLAPSE_WAIT); 1711 1712 #if VM_NRESERVLEVEL > 0 1713 /* 1714 * Break any reservations from backing_object. 1715 */ 1716 if (__predict_false(!LIST_EMPTY(&backing_object->rvq))) 1717 vm_reserv_break_all(backing_object); 1718 #endif 1719 1720 /* 1721 * Move the pager from backing_object to object. 1722 */ 1723 if (backing_object->type == OBJT_SWAP) { 1724 /* 1725 * swap_pager_copy() can sleep, in which case 1726 * the backing_object's and object's locks are 1727 * released and reacquired. 1728 * Since swap_pager_copy() is being asked to 1729 * destroy the source, it will change the 1730 * backing_object's type to OBJT_DEFAULT. 1731 */ 1732 swap_pager_copy( 1733 backing_object, 1734 object, 1735 OFF_TO_IDX(object->backing_object_offset), TRUE); 1736 1737 /* 1738 * Free any cached pages from backing_object. 1739 */ 1740 if (__predict_false(backing_object->cache != NULL)) 1741 vm_page_cache_free(backing_object, 0, 0); 1742 } 1743 /* 1744 * Object now shadows whatever backing_object did. 1745 * Note that the reference to 1746 * backing_object->backing_object moves from within 1747 * backing_object to within object. 1748 */ 1749 LIST_REMOVE(object, shadow_list); 1750 backing_object->shadow_count--; 1751 if (backing_object->backing_object) { 1752 VM_OBJECT_LOCK(backing_object->backing_object); 1753 LIST_REMOVE(backing_object, shadow_list); 1754 LIST_INSERT_HEAD( 1755 &backing_object->backing_object->shadow_head, 1756 object, shadow_list); 1757 /* 1758 * The shadow_count has not changed. 1759 */ 1760 VM_OBJECT_UNLOCK(backing_object->backing_object); 1761 } 1762 object->backing_object = backing_object->backing_object; 1763 object->backing_object_offset += 1764 backing_object->backing_object_offset; 1765 1766 /* 1767 * Discard backing_object. 1768 * 1769 * Since the backing object has no pages, no pager left, 1770 * and no object references within it, all that is 1771 * necessary is to dispose of it. 1772 */ 1773 KASSERT(backing_object->ref_count == 1, ( 1774 "backing_object %p was somehow re-referenced during collapse!", 1775 backing_object)); 1776 VM_OBJECT_UNLOCK(backing_object); 1777 vm_object_destroy(backing_object); 1778 1779 object_collapses++; 1780 } else { 1781 vm_object_t new_backing_object; 1782 1783 /* 1784 * If we do not entirely shadow the backing object, 1785 * there is nothing we can do so we give up. 1786 */ 1787 if (object->resident_page_count != object->size && 1788 vm_object_backing_scan(object, 1789 OBSC_TEST_ALL_SHADOWED) == 0) { 1790 VM_OBJECT_UNLOCK(backing_object); 1791 break; 1792 } 1793 1794 /* 1795 * Make the parent shadow the next object in the 1796 * chain. Deallocating backing_object will not remove 1797 * it, since its reference count is at least 2. 1798 */ 1799 LIST_REMOVE(object, shadow_list); 1800 backing_object->shadow_count--; 1801 1802 new_backing_object = backing_object->backing_object; 1803 if ((object->backing_object = new_backing_object) != NULL) { 1804 VM_OBJECT_LOCK(new_backing_object); 1805 LIST_INSERT_HEAD( 1806 &new_backing_object->shadow_head, 1807 object, 1808 shadow_list 1809 ); 1810 new_backing_object->shadow_count++; 1811 vm_object_reference_locked(new_backing_object); 1812 VM_OBJECT_UNLOCK(new_backing_object); 1813 object->backing_object_offset += 1814 backing_object->backing_object_offset; 1815 } 1816 1817 /* 1818 * Drop the reference count on backing_object. Since 1819 * its ref_count was at least 2, it will not vanish. 1820 */ 1821 backing_object->ref_count--; 1822 VM_OBJECT_UNLOCK(backing_object); 1823 object_bypasses++; 1824 } 1825 1826 /* 1827 * Try again with this object's new backing object. 1828 */ 1829 } 1830 } 1831 1832 /* 1833 * vm_object_page_remove: 1834 * 1835 * For the given object, either frees or invalidates each of the 1836 * specified pages. In general, a page is freed. However, if a page is 1837 * wired for any reason other than the existence of a managed, wired 1838 * mapping, then it may be invalidated but not removed from the object. 1839 * Pages are specified by the given range ["start", "end") and the option 1840 * OBJPR_CLEANONLY. As a special case, if "end" is zero, then the range 1841 * extends from "start" to the end of the object. If the option 1842 * OBJPR_CLEANONLY is specified, then only the non-dirty pages within the 1843 * specified range are affected. If the option OBJPR_NOTMAPPED is 1844 * specified, then the pages within the specified range must have no 1845 * mappings. Otherwise, if this option is not specified, any mappings to 1846 * the specified pages are removed before the pages are freed or 1847 * invalidated. 1848 * 1849 * In general, this operation should only be performed on objects that 1850 * contain managed pages. There are, however, two exceptions. First, it 1851 * is performed on the kernel and kmem objects by vm_map_entry_delete(). 1852 * Second, it is used by msync(..., MS_INVALIDATE) to invalidate device- 1853 * backed pages. In both of these cases, the option OBJPR_CLEANONLY must 1854 * not be specified and the option OBJPR_NOTMAPPED must be specified. 1855 * 1856 * The object must be locked. 1857 */ 1858 void 1859 vm_object_page_remove(vm_object_t object, vm_pindex_t start, vm_pindex_t end, 1860 int options) 1861 { 1862 vm_page_t p, next; 1863 int wirings; 1864 1865 VM_OBJECT_LOCK_ASSERT(object, MA_OWNED); 1866 KASSERT((object->type != OBJT_DEVICE && object->type != OBJT_PHYS) || 1867 (options & (OBJPR_CLEANONLY | OBJPR_NOTMAPPED)) == OBJPR_NOTMAPPED, 1868 ("vm_object_page_remove: illegal options for object %p", object)); 1869 if (object->resident_page_count == 0) 1870 goto skipmemq; 1871 vm_object_pip_add(object, 1); 1872 again: 1873 p = vm_page_find_least(object, start); 1874 1875 /* 1876 * Here, the variable "p" is either (1) the page with the least pindex 1877 * greater than or equal to the parameter "start" or (2) NULL. 1878 */ 1879 for (; p != NULL && (p->pindex < end || end == 0); p = next) { 1880 next = TAILQ_NEXT(p, listq); 1881 1882 /* 1883 * If the page is wired for any reason besides the existence 1884 * of managed, wired mappings, then it cannot be freed. For 1885 * example, fictitious pages, which represent device memory, 1886 * are inherently wired and cannot be freed. They can, 1887 * however, be invalidated if the option OBJPR_CLEANONLY is 1888 * not specified. 1889 */ 1890 vm_page_lock(p); 1891 if ((wirings = p->wire_count) != 0 && 1892 (wirings = pmap_page_wired_mappings(p)) != p->wire_count) { 1893 if ((options & OBJPR_NOTMAPPED) == 0) { 1894 pmap_remove_all(p); 1895 /* Account for removal of wired mappings. */ 1896 if (wirings != 0) 1897 p->wire_count -= wirings; 1898 } 1899 if ((options & OBJPR_CLEANONLY) == 0) { 1900 p->valid = 0; 1901 vm_page_undirty(p); 1902 } 1903 vm_page_unlock(p); 1904 continue; 1905 } 1906 if (vm_page_sleep_if_busy(p, TRUE, "vmopar")) 1907 goto again; 1908 KASSERT((p->flags & PG_FICTITIOUS) == 0, 1909 ("vm_object_page_remove: page %p is fictitious", p)); 1910 if ((options & OBJPR_CLEANONLY) != 0 && p->valid != 0) { 1911 if ((options & OBJPR_NOTMAPPED) == 0) 1912 pmap_remove_write(p); 1913 if (p->dirty) { 1914 vm_page_unlock(p); 1915 continue; 1916 } 1917 } 1918 if ((options & OBJPR_NOTMAPPED) == 0) { 1919 pmap_remove_all(p); 1920 /* Account for removal of wired mappings. */ 1921 if (wirings != 0) { 1922 KASSERT(p->wire_count == wirings, 1923 ("inconsistent wire count %d %d %p", 1924 p->wire_count, wirings, p)); 1925 p->wire_count = 0; 1926 atomic_subtract_int(&cnt.v_wire_count, 1); 1927 } 1928 } 1929 vm_page_free(p); 1930 vm_page_unlock(p); 1931 } 1932 vm_object_pip_wakeup(object); 1933 skipmemq: 1934 if (__predict_false(object->cache != NULL)) 1935 vm_page_cache_free(object, start, end); 1936 } 1937 1938 /* 1939 * vm_object_page_cache: 1940 * 1941 * For the given object, attempt to move the specified clean 1942 * pages to the cache queue. If a page is wired for any reason, 1943 * then it will not be changed. Pages are specified by the given 1944 * range ["start", "end"). As a special case, if "end" is zero, 1945 * then the range extends from "start" to the end of the object. 1946 * Any mappings to the specified pages are removed before the 1947 * pages are moved to the cache queue. 1948 * 1949 * This operation should only be performed on objects that 1950 * contain managed pages. 1951 * 1952 * The object must be locked. 1953 */ 1954 void 1955 vm_object_page_cache(vm_object_t object, vm_pindex_t start, vm_pindex_t end) 1956 { 1957 struct mtx *mtx, *new_mtx; 1958 vm_page_t p, next; 1959 1960 VM_OBJECT_LOCK_ASSERT(object, MA_OWNED); 1961 KASSERT((object->type != OBJT_DEVICE && object->type != OBJT_SG && 1962 object->type != OBJT_PHYS), 1963 ("vm_object_page_cache: illegal object %p", object)); 1964 if (object->resident_page_count == 0) 1965 return; 1966 p = vm_page_find_least(object, start); 1967 1968 /* 1969 * Here, the variable "p" is either (1) the page with the least pindex 1970 * greater than or equal to the parameter "start" or (2) NULL. 1971 */ 1972 mtx = NULL; 1973 for (; p != NULL && (p->pindex < end || end == 0); p = next) { 1974 next = TAILQ_NEXT(p, listq); 1975 1976 /* 1977 * Avoid releasing and reacquiring the same page lock. 1978 */ 1979 new_mtx = vm_page_lockptr(p); 1980 if (mtx != new_mtx) { 1981 if (mtx != NULL) 1982 mtx_unlock(mtx); 1983 mtx = new_mtx; 1984 mtx_lock(mtx); 1985 } 1986 vm_page_try_to_cache(p); 1987 } 1988 if (mtx != NULL) 1989 mtx_unlock(mtx); 1990 } 1991 1992 /* 1993 * Populate the specified range of the object with valid pages. Returns 1994 * TRUE if the range is successfully populated and FALSE otherwise. 1995 * 1996 * Note: This function should be optimized to pass a larger array of 1997 * pages to vm_pager_get_pages() before it is applied to a non- 1998 * OBJT_DEVICE object. 1999 * 2000 * The object must be locked. 2001 */ 2002 boolean_t 2003 vm_object_populate(vm_object_t object, vm_pindex_t start, vm_pindex_t end) 2004 { 2005 vm_page_t m, ma[1]; 2006 vm_pindex_t pindex; 2007 int rv; 2008 2009 VM_OBJECT_LOCK_ASSERT(object, MA_OWNED); 2010 for (pindex = start; pindex < end; pindex++) { 2011 m = vm_page_grab(object, pindex, VM_ALLOC_NORMAL | 2012 VM_ALLOC_RETRY); 2013 if (m->valid != VM_PAGE_BITS_ALL) { 2014 ma[0] = m; 2015 rv = vm_pager_get_pages(object, ma, 1, 0); 2016 m = vm_page_lookup(object, pindex); 2017 if (m == NULL) 2018 break; 2019 if (rv != VM_PAGER_OK) { 2020 vm_page_lock(m); 2021 vm_page_free(m); 2022 vm_page_unlock(m); 2023 break; 2024 } 2025 } 2026 /* 2027 * Keep "m" busy because a subsequent iteration may unlock 2028 * the object. 2029 */ 2030 } 2031 if (pindex > start) { 2032 m = vm_page_lookup(object, start); 2033 while (m != NULL && m->pindex < pindex) { 2034 vm_page_wakeup(m); 2035 m = TAILQ_NEXT(m, listq); 2036 } 2037 } 2038 return (pindex == end); 2039 } 2040 2041 /* 2042 * Routine: vm_object_coalesce 2043 * Function: Coalesces two objects backing up adjoining 2044 * regions of memory into a single object. 2045 * 2046 * returns TRUE if objects were combined. 2047 * 2048 * NOTE: Only works at the moment if the second object is NULL - 2049 * if it's not, which object do we lock first? 2050 * 2051 * Parameters: 2052 * prev_object First object to coalesce 2053 * prev_offset Offset into prev_object 2054 * prev_size Size of reference to prev_object 2055 * next_size Size of reference to the second object 2056 * reserved Indicator that extension region has 2057 * swap accounted for 2058 * 2059 * Conditions: 2060 * The object must *not* be locked. 2061 */ 2062 boolean_t 2063 vm_object_coalesce(vm_object_t prev_object, vm_ooffset_t prev_offset, 2064 vm_size_t prev_size, vm_size_t next_size, boolean_t reserved) 2065 { 2066 vm_pindex_t next_pindex; 2067 2068 if (prev_object == NULL) 2069 return (TRUE); 2070 VM_OBJECT_LOCK(prev_object); 2071 if (prev_object->type != OBJT_DEFAULT && 2072 prev_object->type != OBJT_SWAP) { 2073 VM_OBJECT_UNLOCK(prev_object); 2074 return (FALSE); 2075 } 2076 2077 /* 2078 * Try to collapse the object first 2079 */ 2080 vm_object_collapse(prev_object); 2081 2082 /* 2083 * Can't coalesce if: . more than one reference . paged out . shadows 2084 * another object . has a copy elsewhere (any of which mean that the 2085 * pages not mapped to prev_entry may be in use anyway) 2086 */ 2087 if (prev_object->backing_object != NULL) { 2088 VM_OBJECT_UNLOCK(prev_object); 2089 return (FALSE); 2090 } 2091 2092 prev_size >>= PAGE_SHIFT; 2093 next_size >>= PAGE_SHIFT; 2094 next_pindex = OFF_TO_IDX(prev_offset) + prev_size; 2095 2096 if ((prev_object->ref_count > 1) && 2097 (prev_object->size != next_pindex)) { 2098 VM_OBJECT_UNLOCK(prev_object); 2099 return (FALSE); 2100 } 2101 2102 /* 2103 * Account for the charge. 2104 */ 2105 if (prev_object->cred != NULL) { 2106 2107 /* 2108 * If prev_object was charged, then this mapping, 2109 * althought not charged now, may become writable 2110 * later. Non-NULL cred in the object would prevent 2111 * swap reservation during enabling of the write 2112 * access, so reserve swap now. Failed reservation 2113 * cause allocation of the separate object for the map 2114 * entry, and swap reservation for this entry is 2115 * managed in appropriate time. 2116 */ 2117 if (!reserved && !swap_reserve_by_cred(ptoa(next_size), 2118 prev_object->cred)) { 2119 return (FALSE); 2120 } 2121 prev_object->charge += ptoa(next_size); 2122 } 2123 2124 /* 2125 * Remove any pages that may still be in the object from a previous 2126 * deallocation. 2127 */ 2128 if (next_pindex < prev_object->size) { 2129 vm_object_page_remove(prev_object, next_pindex, next_pindex + 2130 next_size, 0); 2131 if (prev_object->type == OBJT_SWAP) 2132 swap_pager_freespace(prev_object, 2133 next_pindex, next_size); 2134 #if 0 2135 if (prev_object->cred != NULL) { 2136 KASSERT(prev_object->charge >= 2137 ptoa(prev_object->size - next_pindex), 2138 ("object %p overcharged 1 %jx %jx", prev_object, 2139 (uintmax_t)next_pindex, (uintmax_t)next_size)); 2140 prev_object->charge -= ptoa(prev_object->size - 2141 next_pindex); 2142 } 2143 #endif 2144 } 2145 2146 /* 2147 * Extend the object if necessary. 2148 */ 2149 if (next_pindex + next_size > prev_object->size) 2150 prev_object->size = next_pindex + next_size; 2151 2152 VM_OBJECT_UNLOCK(prev_object); 2153 return (TRUE); 2154 } 2155 2156 void 2157 vm_object_set_writeable_dirty(vm_object_t object) 2158 { 2159 2160 VM_OBJECT_LOCK_ASSERT(object, MA_OWNED); 2161 if (object->type != OBJT_VNODE) 2162 return; 2163 object->generation++; 2164 if ((object->flags & OBJ_MIGHTBEDIRTY) != 0) 2165 return; 2166 vm_object_set_flag(object, OBJ_MIGHTBEDIRTY); 2167 } 2168 2169 #include "opt_ddb.h" 2170 #ifdef DDB 2171 #include <sys/kernel.h> 2172 2173 #include <sys/cons.h> 2174 2175 #include <ddb/ddb.h> 2176 2177 static int 2178 _vm_object_in_map(vm_map_t map, vm_object_t object, vm_map_entry_t entry) 2179 { 2180 vm_map_t tmpm; 2181 vm_map_entry_t tmpe; 2182 vm_object_t obj; 2183 int entcount; 2184 2185 if (map == 0) 2186 return 0; 2187 2188 if (entry == 0) { 2189 tmpe = map->header.next; 2190 entcount = map->nentries; 2191 while (entcount-- && (tmpe != &map->header)) { 2192 if (_vm_object_in_map(map, object, tmpe)) { 2193 return 1; 2194 } 2195 tmpe = tmpe->next; 2196 } 2197 } else if (entry->eflags & MAP_ENTRY_IS_SUB_MAP) { 2198 tmpm = entry->object.sub_map; 2199 tmpe = tmpm->header.next; 2200 entcount = tmpm->nentries; 2201 while (entcount-- && tmpe != &tmpm->header) { 2202 if (_vm_object_in_map(tmpm, object, tmpe)) { 2203 return 1; 2204 } 2205 tmpe = tmpe->next; 2206 } 2207 } else if ((obj = entry->object.vm_object) != NULL) { 2208 for (; obj; obj = obj->backing_object) 2209 if (obj == object) { 2210 return 1; 2211 } 2212 } 2213 return 0; 2214 } 2215 2216 static int 2217 vm_object_in_map(vm_object_t object) 2218 { 2219 struct proc *p; 2220 2221 /* sx_slock(&allproc_lock); */ 2222 FOREACH_PROC_IN_SYSTEM(p) { 2223 if (!p->p_vmspace /* || (p->p_flag & (P_SYSTEM|P_WEXIT)) */) 2224 continue; 2225 if (_vm_object_in_map(&p->p_vmspace->vm_map, object, 0)) { 2226 /* sx_sunlock(&allproc_lock); */ 2227 return 1; 2228 } 2229 } 2230 /* sx_sunlock(&allproc_lock); */ 2231 if (_vm_object_in_map(kernel_map, object, 0)) 2232 return 1; 2233 if (_vm_object_in_map(kmem_map, object, 0)) 2234 return 1; 2235 if (_vm_object_in_map(pager_map, object, 0)) 2236 return 1; 2237 if (_vm_object_in_map(buffer_map, object, 0)) 2238 return 1; 2239 return 0; 2240 } 2241 2242 DB_SHOW_COMMAND(vmochk, vm_object_check) 2243 { 2244 vm_object_t object; 2245 2246 /* 2247 * make sure that internal objs are in a map somewhere 2248 * and none have zero ref counts. 2249 */ 2250 TAILQ_FOREACH(object, &vm_object_list, object_list) { 2251 if (object->handle == NULL && 2252 (object->type == OBJT_DEFAULT || object->type == OBJT_SWAP)) { 2253 if (object->ref_count == 0) { 2254 db_printf("vmochk: internal obj has zero ref count: %ld\n", 2255 (long)object->size); 2256 } 2257 if (!vm_object_in_map(object)) { 2258 db_printf( 2259 "vmochk: internal obj is not in a map: " 2260 "ref: %d, size: %lu: 0x%lx, backing_object: %p\n", 2261 object->ref_count, (u_long)object->size, 2262 (u_long)object->size, 2263 (void *)object->backing_object); 2264 } 2265 } 2266 } 2267 } 2268 2269 /* 2270 * vm_object_print: [ debug ] 2271 */ 2272 DB_SHOW_COMMAND(object, vm_object_print_static) 2273 { 2274 /* XXX convert args. */ 2275 vm_object_t object = (vm_object_t)addr; 2276 boolean_t full = have_addr; 2277 2278 vm_page_t p; 2279 2280 /* XXX count is an (unused) arg. Avoid shadowing it. */ 2281 #define count was_count 2282 2283 int count; 2284 2285 if (object == NULL) 2286 return; 2287 2288 db_iprintf( 2289 "Object %p: type=%d, size=0x%jx, res=%d, ref=%d, flags=0x%x ruid %d charge %jx\n", 2290 object, (int)object->type, (uintmax_t)object->size, 2291 object->resident_page_count, object->ref_count, object->flags, 2292 object->cred ? object->cred->cr_ruid : -1, (uintmax_t)object->charge); 2293 db_iprintf(" sref=%d, backing_object(%d)=(%p)+0x%jx\n", 2294 object->shadow_count, 2295 object->backing_object ? object->backing_object->ref_count : 0, 2296 object->backing_object, (uintmax_t)object->backing_object_offset); 2297 2298 if (!full) 2299 return; 2300 2301 db_indent += 2; 2302 count = 0; 2303 TAILQ_FOREACH(p, &object->memq, listq) { 2304 if (count == 0) 2305 db_iprintf("memory:="); 2306 else if (count == 6) { 2307 db_printf("\n"); 2308 db_iprintf(" ..."); 2309 count = 0; 2310 } else 2311 db_printf(","); 2312 count++; 2313 2314 db_printf("(off=0x%jx,page=0x%jx)", 2315 (uintmax_t)p->pindex, (uintmax_t)VM_PAGE_TO_PHYS(p)); 2316 } 2317 if (count != 0) 2318 db_printf("\n"); 2319 db_indent -= 2; 2320 } 2321 2322 /* XXX. */ 2323 #undef count 2324 2325 /* XXX need this non-static entry for calling from vm_map_print. */ 2326 void 2327 vm_object_print( 2328 /* db_expr_t */ long addr, 2329 boolean_t have_addr, 2330 /* db_expr_t */ long count, 2331 char *modif) 2332 { 2333 vm_object_print_static(addr, have_addr, count, modif); 2334 } 2335 2336 DB_SHOW_COMMAND(vmopag, vm_object_print_pages) 2337 { 2338 vm_object_t object; 2339 vm_pindex_t fidx; 2340 vm_paddr_t pa; 2341 vm_page_t m, prev_m; 2342 int rcount, nl, c; 2343 2344 nl = 0; 2345 TAILQ_FOREACH(object, &vm_object_list, object_list) { 2346 db_printf("new object: %p\n", (void *)object); 2347 if (nl > 18) { 2348 c = cngetc(); 2349 if (c != ' ') 2350 return; 2351 nl = 0; 2352 } 2353 nl++; 2354 rcount = 0; 2355 fidx = 0; 2356 pa = -1; 2357 TAILQ_FOREACH(m, &object->memq, listq) { 2358 if (m->pindex > 128) 2359 break; 2360 if ((prev_m = TAILQ_PREV(m, pglist, listq)) != NULL && 2361 prev_m->pindex + 1 != m->pindex) { 2362 if (rcount) { 2363 db_printf(" index(%ld)run(%d)pa(0x%lx)\n", 2364 (long)fidx, rcount, (long)pa); 2365 if (nl > 18) { 2366 c = cngetc(); 2367 if (c != ' ') 2368 return; 2369 nl = 0; 2370 } 2371 nl++; 2372 rcount = 0; 2373 } 2374 } 2375 if (rcount && 2376 (VM_PAGE_TO_PHYS(m) == pa + rcount * PAGE_SIZE)) { 2377 ++rcount; 2378 continue; 2379 } 2380 if (rcount) { 2381 db_printf(" index(%ld)run(%d)pa(0x%lx)\n", 2382 (long)fidx, rcount, (long)pa); 2383 if (nl > 18) { 2384 c = cngetc(); 2385 if (c != ' ') 2386 return; 2387 nl = 0; 2388 } 2389 nl++; 2390 } 2391 fidx = m->pindex; 2392 pa = VM_PAGE_TO_PHYS(m); 2393 rcount = 1; 2394 } 2395 if (rcount) { 2396 db_printf(" index(%ld)run(%d)pa(0x%lx)\n", 2397 (long)fidx, rcount, (long)pa); 2398 if (nl > 18) { 2399 c = cngetc(); 2400 if (c != ' ') 2401 return; 2402 nl = 0; 2403 } 2404 nl++; 2405 } 2406 } 2407 } 2408 #endif /* DDB */ 2409