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 switch (type) { 216 case OBJT_DEAD: 217 panic("_vm_object_allocate: can't create OBJT_DEAD"); 218 case OBJT_DEFAULT: 219 case OBJT_SWAP: 220 object->flags = OBJ_ONEMAPPING; 221 break; 222 case OBJT_DEVICE: 223 case OBJT_SG: 224 object->flags = OBJ_FICTITIOUS | OBJ_UNMANAGED; 225 break; 226 case OBJT_MGTDEVICE: 227 object->flags = OBJ_FICTITIOUS; 228 break; 229 case OBJT_PHYS: 230 object->flags = OBJ_UNMANAGED; 231 break; 232 case OBJT_VNODE: 233 object->flags = 0; 234 break; 235 default: 236 panic("_vm_object_allocate: type %d is undefined", type); 237 } 238 object->size = size; 239 object->generation = 1; 240 object->ref_count = 1; 241 object->memattr = VM_MEMATTR_DEFAULT; 242 object->cred = NULL; 243 object->charge = 0; 244 object->pg_color = 0; 245 object->handle = NULL; 246 object->backing_object = NULL; 247 object->backing_object_offset = (vm_ooffset_t) 0; 248 #if VM_NRESERVLEVEL > 0 249 LIST_INIT(&object->rvq); 250 #endif 251 object->cache = NULL; 252 253 mtx_lock(&vm_object_list_mtx); 254 TAILQ_INSERT_TAIL(&vm_object_list, object, object_list); 255 mtx_unlock(&vm_object_list_mtx); 256 } 257 258 /* 259 * vm_object_init: 260 * 261 * Initialize the VM objects module. 262 */ 263 void 264 vm_object_init(void) 265 { 266 TAILQ_INIT(&vm_object_list); 267 mtx_init(&vm_object_list_mtx, "vm object_list", NULL, MTX_DEF); 268 269 VM_OBJECT_LOCK_INIT(kernel_object, "kernel object"); 270 _vm_object_allocate(OBJT_PHYS, OFF_TO_IDX(VM_MAX_KERNEL_ADDRESS - VM_MIN_KERNEL_ADDRESS), 271 kernel_object); 272 #if VM_NRESERVLEVEL > 0 273 kernel_object->flags |= OBJ_COLORED; 274 kernel_object->pg_color = (u_short)atop(VM_MIN_KERNEL_ADDRESS); 275 #endif 276 277 VM_OBJECT_LOCK_INIT(kmem_object, "kmem object"); 278 _vm_object_allocate(OBJT_PHYS, OFF_TO_IDX(VM_MAX_KERNEL_ADDRESS - VM_MIN_KERNEL_ADDRESS), 279 kmem_object); 280 #if VM_NRESERVLEVEL > 0 281 kmem_object->flags |= OBJ_COLORED; 282 kmem_object->pg_color = (u_short)atop(VM_MIN_KERNEL_ADDRESS); 283 #endif 284 285 /* 286 * The lock portion of struct vm_object must be type stable due 287 * to vm_pageout_fallback_object_lock locking a vm object 288 * without holding any references to it. 289 */ 290 obj_zone = uma_zcreate("VM OBJECT", sizeof (struct vm_object), NULL, 291 #ifdef INVARIANTS 292 vm_object_zdtor, 293 #else 294 NULL, 295 #endif 296 vm_object_zinit, NULL, UMA_ALIGN_PTR, UMA_ZONE_VM|UMA_ZONE_NOFREE); 297 } 298 299 void 300 vm_object_clear_flag(vm_object_t object, u_short bits) 301 { 302 303 VM_OBJECT_LOCK_ASSERT(object, MA_OWNED); 304 object->flags &= ~bits; 305 } 306 307 /* 308 * Sets the default memory attribute for the specified object. Pages 309 * that are allocated to this object are by default assigned this memory 310 * attribute. 311 * 312 * Presently, this function must be called before any pages are allocated 313 * to the object. In the future, this requirement may be relaxed for 314 * "default" and "swap" objects. 315 */ 316 int 317 vm_object_set_memattr(vm_object_t object, vm_memattr_t memattr) 318 { 319 320 VM_OBJECT_LOCK_ASSERT(object, MA_OWNED); 321 switch (object->type) { 322 case OBJT_DEFAULT: 323 case OBJT_DEVICE: 324 case OBJT_MGTDEVICE: 325 case OBJT_PHYS: 326 case OBJT_SG: 327 case OBJT_SWAP: 328 case OBJT_VNODE: 329 if (!TAILQ_EMPTY(&object->memq)) 330 return (KERN_FAILURE); 331 break; 332 case OBJT_DEAD: 333 return (KERN_INVALID_ARGUMENT); 334 default: 335 panic("vm_object_set_memattr: object %p is of undefined type", 336 object); 337 } 338 object->memattr = memattr; 339 return (KERN_SUCCESS); 340 } 341 342 void 343 vm_object_pip_add(vm_object_t object, short i) 344 { 345 346 VM_OBJECT_LOCK_ASSERT(object, MA_OWNED); 347 object->paging_in_progress += i; 348 } 349 350 void 351 vm_object_pip_subtract(vm_object_t object, short i) 352 { 353 354 VM_OBJECT_LOCK_ASSERT(object, MA_OWNED); 355 object->paging_in_progress -= i; 356 } 357 358 void 359 vm_object_pip_wakeup(vm_object_t object) 360 { 361 362 VM_OBJECT_LOCK_ASSERT(object, MA_OWNED); 363 object->paging_in_progress--; 364 if ((object->flags & OBJ_PIPWNT) && object->paging_in_progress == 0) { 365 vm_object_clear_flag(object, OBJ_PIPWNT); 366 wakeup(object); 367 } 368 } 369 370 void 371 vm_object_pip_wakeupn(vm_object_t object, short i) 372 { 373 374 VM_OBJECT_LOCK_ASSERT(object, MA_OWNED); 375 if (i) 376 object->paging_in_progress -= i; 377 if ((object->flags & OBJ_PIPWNT) && object->paging_in_progress == 0) { 378 vm_object_clear_flag(object, OBJ_PIPWNT); 379 wakeup(object); 380 } 381 } 382 383 void 384 vm_object_pip_wait(vm_object_t object, char *waitid) 385 { 386 387 VM_OBJECT_LOCK_ASSERT(object, MA_OWNED); 388 while (object->paging_in_progress) { 389 object->flags |= OBJ_PIPWNT; 390 msleep(object, VM_OBJECT_MTX(object), PVM, waitid, 0); 391 } 392 } 393 394 /* 395 * vm_object_allocate: 396 * 397 * Returns a new object with the given size. 398 */ 399 vm_object_t 400 vm_object_allocate(objtype_t type, vm_pindex_t size) 401 { 402 vm_object_t object; 403 404 object = (vm_object_t)uma_zalloc(obj_zone, M_WAITOK); 405 _vm_object_allocate(type, size, object); 406 return (object); 407 } 408 409 410 /* 411 * vm_object_reference: 412 * 413 * Gets another reference to the given object. Note: OBJ_DEAD 414 * objects can be referenced during final cleaning. 415 */ 416 void 417 vm_object_reference(vm_object_t object) 418 { 419 if (object == NULL) 420 return; 421 VM_OBJECT_LOCK(object); 422 vm_object_reference_locked(object); 423 VM_OBJECT_UNLOCK(object); 424 } 425 426 /* 427 * vm_object_reference_locked: 428 * 429 * Gets another reference to the given object. 430 * 431 * The object must be locked. 432 */ 433 void 434 vm_object_reference_locked(vm_object_t object) 435 { 436 struct vnode *vp; 437 438 VM_OBJECT_LOCK_ASSERT(object, MA_OWNED); 439 object->ref_count++; 440 if (object->type == OBJT_VNODE) { 441 vp = object->handle; 442 vref(vp); 443 } 444 } 445 446 /* 447 * Handle deallocating an object of type OBJT_VNODE. 448 */ 449 static void 450 vm_object_vndeallocate(vm_object_t object) 451 { 452 struct vnode *vp = (struct vnode *) object->handle; 453 454 VM_OBJECT_LOCK_ASSERT(object, MA_OWNED); 455 KASSERT(object->type == OBJT_VNODE, 456 ("vm_object_vndeallocate: not a vnode object")); 457 KASSERT(vp != NULL, ("vm_object_vndeallocate: missing vp")); 458 #ifdef INVARIANTS 459 if (object->ref_count == 0) { 460 vprint("vm_object_vndeallocate", vp); 461 panic("vm_object_vndeallocate: bad object reference count"); 462 } 463 #endif 464 465 if (object->ref_count > 1) { 466 object->ref_count--; 467 VM_OBJECT_UNLOCK(object); 468 /* vrele may need the vnode lock. */ 469 vrele(vp); 470 } else { 471 vhold(vp); 472 VM_OBJECT_UNLOCK(object); 473 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY); 474 vdrop(vp); 475 VM_OBJECT_LOCK(object); 476 object->ref_count--; 477 if (object->type == OBJT_DEAD) { 478 VM_OBJECT_UNLOCK(object); 479 VOP_UNLOCK(vp, 0); 480 } else { 481 if (object->ref_count == 0) 482 VOP_UNSET_TEXT(vp); 483 VM_OBJECT_UNLOCK(object); 484 vput(vp); 485 } 486 } 487 } 488 489 /* 490 * vm_object_deallocate: 491 * 492 * Release a reference to the specified object, 493 * gained either through a vm_object_allocate 494 * or a vm_object_reference call. When all references 495 * are gone, storage associated with this object 496 * may be relinquished. 497 * 498 * No object may be locked. 499 */ 500 void 501 vm_object_deallocate(vm_object_t object) 502 { 503 vm_object_t temp; 504 505 while (object != NULL) { 506 VM_OBJECT_LOCK(object); 507 if (object->type == OBJT_VNODE) { 508 vm_object_vndeallocate(object); 509 return; 510 } 511 512 KASSERT(object->ref_count != 0, 513 ("vm_object_deallocate: object deallocated too many times: %d", object->type)); 514 515 /* 516 * If the reference count goes to 0 we start calling 517 * vm_object_terminate() on the object chain. 518 * A ref count of 1 may be a special case depending on the 519 * shadow count being 0 or 1. 520 */ 521 object->ref_count--; 522 if (object->ref_count > 1) { 523 VM_OBJECT_UNLOCK(object); 524 return; 525 } else if (object->ref_count == 1) { 526 if (object->shadow_count == 0 && 527 object->handle == NULL && 528 (object->type == OBJT_DEFAULT || 529 object->type == OBJT_SWAP)) { 530 vm_object_set_flag(object, OBJ_ONEMAPPING); 531 } else if ((object->shadow_count == 1) && 532 (object->handle == NULL) && 533 (object->type == OBJT_DEFAULT || 534 object->type == OBJT_SWAP)) { 535 vm_object_t robject; 536 537 robject = LIST_FIRST(&object->shadow_head); 538 KASSERT(robject != NULL, 539 ("vm_object_deallocate: ref_count: %d, shadow_count: %d", 540 object->ref_count, 541 object->shadow_count)); 542 if (!VM_OBJECT_TRYLOCK(robject)) { 543 /* 544 * Avoid a potential deadlock. 545 */ 546 object->ref_count++; 547 VM_OBJECT_UNLOCK(object); 548 /* 549 * More likely than not the thread 550 * holding robject's lock has lower 551 * priority than the current thread. 552 * Let the lower priority thread run. 553 */ 554 pause("vmo_de", 1); 555 continue; 556 } 557 /* 558 * Collapse object into its shadow unless its 559 * shadow is dead. In that case, object will 560 * be deallocated by the thread that is 561 * deallocating its shadow. 562 */ 563 if ((robject->flags & OBJ_DEAD) == 0 && 564 (robject->handle == NULL) && 565 (robject->type == OBJT_DEFAULT || 566 robject->type == OBJT_SWAP)) { 567 568 robject->ref_count++; 569 retry: 570 if (robject->paging_in_progress) { 571 VM_OBJECT_UNLOCK(object); 572 vm_object_pip_wait(robject, 573 "objde1"); 574 temp = robject->backing_object; 575 if (object == temp) { 576 VM_OBJECT_LOCK(object); 577 goto retry; 578 } 579 } else if (object->paging_in_progress) { 580 VM_OBJECT_UNLOCK(robject); 581 object->flags |= OBJ_PIPWNT; 582 msleep(object, 583 VM_OBJECT_MTX(object), 584 PDROP | PVM, "objde2", 0); 585 VM_OBJECT_LOCK(robject); 586 temp = robject->backing_object; 587 if (object == temp) { 588 VM_OBJECT_LOCK(object); 589 goto retry; 590 } 591 } else 592 VM_OBJECT_UNLOCK(object); 593 594 if (robject->ref_count == 1) { 595 robject->ref_count--; 596 object = robject; 597 goto doterm; 598 } 599 object = robject; 600 vm_object_collapse(object); 601 VM_OBJECT_UNLOCK(object); 602 continue; 603 } 604 VM_OBJECT_UNLOCK(robject); 605 } 606 VM_OBJECT_UNLOCK(object); 607 return; 608 } 609 doterm: 610 temp = object->backing_object; 611 if (temp != NULL) { 612 VM_OBJECT_LOCK(temp); 613 LIST_REMOVE(object, shadow_list); 614 temp->shadow_count--; 615 VM_OBJECT_UNLOCK(temp); 616 object->backing_object = NULL; 617 } 618 /* 619 * Don't double-terminate, we could be in a termination 620 * recursion due to the terminate having to sync data 621 * to disk. 622 */ 623 if ((object->flags & OBJ_DEAD) == 0) 624 vm_object_terminate(object); 625 else 626 VM_OBJECT_UNLOCK(object); 627 object = temp; 628 } 629 } 630 631 /* 632 * vm_object_destroy removes the object from the global object list 633 * and frees the space for the object. 634 */ 635 void 636 vm_object_destroy(vm_object_t object) 637 { 638 639 /* 640 * Remove the object from the global object list. 641 */ 642 mtx_lock(&vm_object_list_mtx); 643 TAILQ_REMOVE(&vm_object_list, object, object_list); 644 mtx_unlock(&vm_object_list_mtx); 645 646 /* 647 * Release the allocation charge. 648 */ 649 if (object->cred != NULL) { 650 KASSERT(object->type == OBJT_DEFAULT || 651 object->type == OBJT_SWAP, 652 ("vm_object_terminate: non-swap obj %p has cred", 653 object)); 654 swap_release_by_cred(object->charge, object->cred); 655 object->charge = 0; 656 crfree(object->cred); 657 object->cred = NULL; 658 } 659 660 /* 661 * Free the space for the object. 662 */ 663 uma_zfree(obj_zone, object); 664 } 665 666 /* 667 * vm_object_terminate actually destroys the specified object, freeing 668 * up all previously used resources. 669 * 670 * The object must be locked. 671 * This routine may block. 672 */ 673 void 674 vm_object_terminate(vm_object_t object) 675 { 676 vm_page_t p, p_next; 677 678 VM_OBJECT_LOCK_ASSERT(object, MA_OWNED); 679 680 /* 681 * Make sure no one uses us. 682 */ 683 vm_object_set_flag(object, OBJ_DEAD); 684 685 /* 686 * wait for the pageout daemon to be done with the object 687 */ 688 vm_object_pip_wait(object, "objtrm"); 689 690 KASSERT(!object->paging_in_progress, 691 ("vm_object_terminate: pageout in progress")); 692 693 /* 694 * Clean and free the pages, as appropriate. All references to the 695 * object are gone, so we don't need to lock it. 696 */ 697 if (object->type == OBJT_VNODE) { 698 struct vnode *vp = (struct vnode *)object->handle; 699 700 /* 701 * Clean pages and flush buffers. 702 */ 703 vm_object_page_clean(object, 0, 0, OBJPC_SYNC); 704 VM_OBJECT_UNLOCK(object); 705 706 vinvalbuf(vp, V_SAVE, 0, 0); 707 708 VM_OBJECT_LOCK(object); 709 } 710 711 KASSERT(object->ref_count == 0, 712 ("vm_object_terminate: object with references, ref_count=%d", 713 object->ref_count)); 714 715 /* 716 * Free any remaining pageable pages. This also removes them from the 717 * paging queues. However, don't free wired pages, just remove them 718 * from the object. Rather than incrementally removing each page from 719 * the object, the page and object are reset to any empty state. 720 */ 721 TAILQ_FOREACH_SAFE(p, &object->memq, listq, p_next) { 722 KASSERT(!p->busy && (p->oflags & VPO_BUSY) == 0, 723 ("vm_object_terminate: freeing busy page %p", p)); 724 vm_page_lock(p); 725 /* 726 * Optimize the page's removal from the object by resetting 727 * its "object" field. Specifically, if the page is not 728 * wired, then the effect of this assignment is that 729 * vm_page_free()'s call to vm_page_remove() will return 730 * immediately without modifying the page or the object. 731 */ 732 p->object = NULL; 733 if (p->wire_count == 0) { 734 vm_page_free(p); 735 PCPU_INC(cnt.v_pfree); 736 } 737 vm_page_unlock(p); 738 } 739 /* 740 * If the object contained any pages, then reset it to an empty state. 741 * None of the object's fields, including "resident_page_count", were 742 * modified by the preceding loop. 743 */ 744 if (object->resident_page_count != 0) { 745 object->root = NULL; 746 TAILQ_INIT(&object->memq); 747 object->resident_page_count = 0; 748 if (object->type == OBJT_VNODE) 749 vdrop(object->handle); 750 } 751 752 #if VM_NRESERVLEVEL > 0 753 if (__predict_false(!LIST_EMPTY(&object->rvq))) 754 vm_reserv_break_all(object); 755 #endif 756 if (__predict_false(object->cache != NULL)) 757 vm_page_cache_free(object, 0, 0); 758 759 /* 760 * Let the pager know object is dead. 761 */ 762 vm_pager_deallocate(object); 763 VM_OBJECT_UNLOCK(object); 764 765 vm_object_destroy(object); 766 } 767 768 /* 769 * Make the page read-only so that we can clear the object flags. However, if 770 * this is a nosync mmap then the object is likely to stay dirty so do not 771 * mess with the page and do not clear the object flags. Returns TRUE if the 772 * page should be flushed, and FALSE otherwise. 773 */ 774 static boolean_t 775 vm_object_page_remove_write(vm_page_t p, int flags, boolean_t *clearobjflags) 776 { 777 778 /* 779 * If we have been asked to skip nosync pages and this is a 780 * nosync page, skip it. Note that the object flags were not 781 * cleared in this case so we do not have to set them. 782 */ 783 if ((flags & OBJPC_NOSYNC) != 0 && (p->oflags & VPO_NOSYNC) != 0) { 784 *clearobjflags = FALSE; 785 return (FALSE); 786 } else { 787 pmap_remove_write(p); 788 return (p->dirty != 0); 789 } 790 } 791 792 /* 793 * vm_object_page_clean 794 * 795 * Clean all dirty pages in the specified range of object. Leaves page 796 * on whatever queue it is currently on. If NOSYNC is set then do not 797 * write out pages with VPO_NOSYNC set (originally comes from MAP_NOSYNC), 798 * leaving the object dirty. 799 * 800 * When stuffing pages asynchronously, allow clustering. XXX we need a 801 * synchronous clustering mode implementation. 802 * 803 * Odd semantics: if start == end, we clean everything. 804 * 805 * The object must be locked. 806 * 807 * Returns FALSE if some page from the range was not written, as 808 * reported by the pager, and TRUE otherwise. 809 */ 810 boolean_t 811 vm_object_page_clean(vm_object_t object, vm_ooffset_t start, vm_ooffset_t end, 812 int flags) 813 { 814 vm_page_t np, p; 815 vm_pindex_t pi, tend, tstart; 816 int curgeneration, n, pagerflags; 817 boolean_t clearobjflags, eio, res; 818 819 VM_OBJECT_LOCK_ASSERT(object, MA_OWNED); 820 KASSERT(object->type == OBJT_VNODE, ("Not a vnode object")); 821 if ((object->flags & OBJ_MIGHTBEDIRTY) == 0 || 822 object->resident_page_count == 0) 823 return (TRUE); 824 825 pagerflags = (flags & (OBJPC_SYNC | OBJPC_INVAL)) != 0 ? 826 VM_PAGER_PUT_SYNC : VM_PAGER_CLUSTER_OK; 827 pagerflags |= (flags & OBJPC_INVAL) != 0 ? VM_PAGER_PUT_INVAL : 0; 828 829 tstart = OFF_TO_IDX(start); 830 tend = (end == 0) ? object->size : OFF_TO_IDX(end + PAGE_MASK); 831 clearobjflags = tstart == 0 && tend >= object->size; 832 res = TRUE; 833 834 rescan: 835 curgeneration = object->generation; 836 837 for (p = vm_page_find_least(object, tstart); p != NULL; p = np) { 838 pi = p->pindex; 839 if (pi >= tend) 840 break; 841 np = TAILQ_NEXT(p, listq); 842 if (p->valid == 0) 843 continue; 844 if (vm_page_sleep_if_busy(p, TRUE, "vpcwai")) { 845 if (object->generation != curgeneration) { 846 if ((flags & OBJPC_SYNC) != 0) 847 goto rescan; 848 else 849 clearobjflags = FALSE; 850 } 851 np = vm_page_find_least(object, pi); 852 continue; 853 } 854 if (!vm_object_page_remove_write(p, flags, &clearobjflags)) 855 continue; 856 857 n = vm_object_page_collect_flush(object, p, pagerflags, 858 flags, &clearobjflags, &eio); 859 if (eio) { 860 res = FALSE; 861 clearobjflags = FALSE; 862 } 863 if (object->generation != curgeneration) { 864 if ((flags & OBJPC_SYNC) != 0) 865 goto rescan; 866 else 867 clearobjflags = FALSE; 868 } 869 870 /* 871 * If the VOP_PUTPAGES() did a truncated write, so 872 * that even the first page of the run is not fully 873 * written, vm_pageout_flush() returns 0 as the run 874 * length. Since the condition that caused truncated 875 * write may be permanent, e.g. exhausted free space, 876 * accepting n == 0 would cause an infinite loop. 877 * 878 * Forwarding the iterator leaves the unwritten page 879 * behind, but there is not much we can do there if 880 * filesystem refuses to write it. 881 */ 882 if (n == 0) { 883 n = 1; 884 clearobjflags = FALSE; 885 } 886 np = vm_page_find_least(object, pi + n); 887 } 888 #if 0 889 VOP_FSYNC(vp, (pagerflags & VM_PAGER_PUT_SYNC) ? MNT_WAIT : 0); 890 #endif 891 892 if (clearobjflags) 893 vm_object_clear_flag(object, OBJ_MIGHTBEDIRTY); 894 return (res); 895 } 896 897 static int 898 vm_object_page_collect_flush(vm_object_t object, vm_page_t p, int pagerflags, 899 int flags, boolean_t *clearobjflags, boolean_t *eio) 900 { 901 vm_page_t ma[vm_pageout_page_count], p_first, tp; 902 int count, i, mreq, runlen; 903 904 vm_page_lock_assert(p, MA_NOTOWNED); 905 VM_OBJECT_LOCK_ASSERT(object, MA_OWNED); 906 907 count = 1; 908 mreq = 0; 909 910 for (tp = p; count < vm_pageout_page_count; count++) { 911 tp = vm_page_next(tp); 912 if (tp == NULL || tp->busy != 0 || (tp->oflags & VPO_BUSY) != 0) 913 break; 914 if (!vm_object_page_remove_write(tp, flags, clearobjflags)) 915 break; 916 } 917 918 for (p_first = p; count < vm_pageout_page_count; count++) { 919 tp = vm_page_prev(p_first); 920 if (tp == NULL || tp->busy != 0 || (tp->oflags & VPO_BUSY) != 0) 921 break; 922 if (!vm_object_page_remove_write(tp, flags, clearobjflags)) 923 break; 924 p_first = tp; 925 mreq++; 926 } 927 928 for (tp = p_first, i = 0; i < count; tp = TAILQ_NEXT(tp, listq), i++) 929 ma[i] = tp; 930 931 vm_pageout_flush(ma, count, pagerflags, mreq, &runlen, eio); 932 return (runlen); 933 } 934 935 /* 936 * Note that there is absolutely no sense in writing out 937 * anonymous objects, so we track down the vnode object 938 * to write out. 939 * We invalidate (remove) all pages from the address space 940 * for semantic correctness. 941 * 942 * If the backing object is a device object with unmanaged pages, then any 943 * mappings to the specified range of pages must be removed before this 944 * function is called. 945 * 946 * Note: certain anonymous maps, such as MAP_NOSYNC maps, 947 * may start out with a NULL object. 948 */ 949 boolean_t 950 vm_object_sync(vm_object_t object, vm_ooffset_t offset, vm_size_t size, 951 boolean_t syncio, boolean_t invalidate) 952 { 953 vm_object_t backing_object; 954 struct vnode *vp; 955 struct mount *mp; 956 int error, flags, fsync_after; 957 boolean_t res; 958 959 if (object == NULL) 960 return (TRUE); 961 res = TRUE; 962 error = 0; 963 VM_OBJECT_LOCK(object); 964 while ((backing_object = object->backing_object) != NULL) { 965 VM_OBJECT_LOCK(backing_object); 966 offset += object->backing_object_offset; 967 VM_OBJECT_UNLOCK(object); 968 object = backing_object; 969 if (object->size < OFF_TO_IDX(offset + size)) 970 size = IDX_TO_OFF(object->size) - offset; 971 } 972 /* 973 * Flush pages if writing is allowed, invalidate them 974 * if invalidation requested. Pages undergoing I/O 975 * will be ignored by vm_object_page_remove(). 976 * 977 * We cannot lock the vnode and then wait for paging 978 * to complete without deadlocking against vm_fault. 979 * Instead we simply call vm_object_page_remove() and 980 * allow it to block internally on a page-by-page 981 * basis when it encounters pages undergoing async 982 * I/O. 983 */ 984 if (object->type == OBJT_VNODE && 985 (object->flags & OBJ_MIGHTBEDIRTY) != 0) { 986 vp = object->handle; 987 VM_OBJECT_UNLOCK(object); 988 (void) vn_start_write(vp, &mp, V_WAIT); 989 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY); 990 if (syncio && !invalidate && offset == 0 && 991 OFF_TO_IDX(size) == object->size) { 992 /* 993 * If syncing the whole mapping of the file, 994 * it is faster to schedule all the writes in 995 * async mode, also allowing the clustering, 996 * and then wait for i/o to complete. 997 */ 998 flags = 0; 999 fsync_after = TRUE; 1000 } else { 1001 flags = (syncio || invalidate) ? OBJPC_SYNC : 0; 1002 flags |= invalidate ? (OBJPC_SYNC | OBJPC_INVAL) : 0; 1003 fsync_after = FALSE; 1004 } 1005 VM_OBJECT_LOCK(object); 1006 res = vm_object_page_clean(object, offset, offset + size, 1007 flags); 1008 VM_OBJECT_UNLOCK(object); 1009 if (fsync_after) 1010 error = VOP_FSYNC(vp, MNT_WAIT, curthread); 1011 VOP_UNLOCK(vp, 0); 1012 vn_finished_write(mp); 1013 if (error != 0) 1014 res = FALSE; 1015 VM_OBJECT_LOCK(object); 1016 } 1017 if ((object->type == OBJT_VNODE || 1018 object->type == OBJT_DEVICE) && invalidate) { 1019 if (object->type == OBJT_DEVICE) 1020 /* 1021 * The option OBJPR_NOTMAPPED must be passed here 1022 * because vm_object_page_remove() cannot remove 1023 * unmanaged mappings. 1024 */ 1025 flags = OBJPR_NOTMAPPED; 1026 else if (old_msync) 1027 flags = 0; 1028 else 1029 flags = OBJPR_CLEANONLY; 1030 vm_object_page_remove(object, OFF_TO_IDX(offset), 1031 OFF_TO_IDX(offset + size + PAGE_MASK), flags); 1032 } 1033 VM_OBJECT_UNLOCK(object); 1034 return (res); 1035 } 1036 1037 /* 1038 * vm_object_madvise: 1039 * 1040 * Implements the madvise function at the object/page level. 1041 * 1042 * MADV_WILLNEED (any object) 1043 * 1044 * Activate the specified pages if they are resident. 1045 * 1046 * MADV_DONTNEED (any object) 1047 * 1048 * Deactivate the specified pages if they are resident. 1049 * 1050 * MADV_FREE (OBJT_DEFAULT/OBJT_SWAP objects, 1051 * OBJ_ONEMAPPING only) 1052 * 1053 * Deactivate and clean the specified pages if they are 1054 * resident. This permits the process to reuse the pages 1055 * without faulting or the kernel to reclaim the pages 1056 * without I/O. 1057 */ 1058 void 1059 vm_object_madvise(vm_object_t object, vm_pindex_t pindex, vm_pindex_t end, 1060 int advise) 1061 { 1062 vm_pindex_t tpindex; 1063 vm_object_t backing_object, tobject; 1064 vm_page_t m; 1065 1066 if (object == NULL) 1067 return; 1068 VM_OBJECT_LOCK(object); 1069 /* 1070 * Locate and adjust resident pages 1071 */ 1072 for (; pindex < end; pindex += 1) { 1073 relookup: 1074 tobject = object; 1075 tpindex = pindex; 1076 shadowlookup: 1077 /* 1078 * MADV_FREE only operates on OBJT_DEFAULT or OBJT_SWAP pages 1079 * and those pages must be OBJ_ONEMAPPING. 1080 */ 1081 if (advise == MADV_FREE) { 1082 if ((tobject->type != OBJT_DEFAULT && 1083 tobject->type != OBJT_SWAP) || 1084 (tobject->flags & OBJ_ONEMAPPING) == 0) { 1085 goto unlock_tobject; 1086 } 1087 } else if ((tobject->flags & OBJ_UNMANAGED) != 0) 1088 goto unlock_tobject; 1089 m = vm_page_lookup(tobject, tpindex); 1090 if (m == NULL && advise == MADV_WILLNEED) { 1091 /* 1092 * If the page is cached, reactivate it. 1093 */ 1094 m = vm_page_alloc(tobject, tpindex, VM_ALLOC_IFCACHED | 1095 VM_ALLOC_NOBUSY); 1096 } 1097 if (m == NULL) { 1098 /* 1099 * There may be swap even if there is no backing page 1100 */ 1101 if (advise == MADV_FREE && tobject->type == OBJT_SWAP) 1102 swap_pager_freespace(tobject, tpindex, 1); 1103 /* 1104 * next object 1105 */ 1106 backing_object = tobject->backing_object; 1107 if (backing_object == NULL) 1108 goto unlock_tobject; 1109 VM_OBJECT_LOCK(backing_object); 1110 tpindex += OFF_TO_IDX(tobject->backing_object_offset); 1111 if (tobject != object) 1112 VM_OBJECT_UNLOCK(tobject); 1113 tobject = backing_object; 1114 goto shadowlookup; 1115 } else if (m->valid != VM_PAGE_BITS_ALL) 1116 goto unlock_tobject; 1117 /* 1118 * If the page is not in a normal state, skip it. 1119 */ 1120 vm_page_lock(m); 1121 if (m->hold_count != 0 || m->wire_count != 0) { 1122 vm_page_unlock(m); 1123 goto unlock_tobject; 1124 } 1125 KASSERT((m->flags & PG_FICTITIOUS) == 0, 1126 ("vm_object_madvise: page %p is fictitious", m)); 1127 KASSERT((m->oflags & VPO_UNMANAGED) == 0, 1128 ("vm_object_madvise: page %p is not managed", m)); 1129 if ((m->oflags & VPO_BUSY) || m->busy) { 1130 if (advise == MADV_WILLNEED) { 1131 /* 1132 * Reference the page before unlocking and 1133 * sleeping so that the page daemon is less 1134 * likely to reclaim it. 1135 */ 1136 vm_page_aflag_set(m, PGA_REFERENCED); 1137 } 1138 vm_page_unlock(m); 1139 if (object != tobject) 1140 VM_OBJECT_UNLOCK(object); 1141 m->oflags |= VPO_WANTED; 1142 msleep(m, VM_OBJECT_MTX(tobject), PDROP | PVM, "madvpo", 1143 0); 1144 VM_OBJECT_LOCK(object); 1145 goto relookup; 1146 } 1147 if (advise == MADV_WILLNEED) { 1148 vm_page_activate(m); 1149 } else if (advise == MADV_DONTNEED) { 1150 vm_page_dontneed(m); 1151 } else if (advise == MADV_FREE) { 1152 /* 1153 * Mark the page clean. This will allow the page 1154 * to be freed up by the system. However, such pages 1155 * are often reused quickly by malloc()/free() 1156 * so we do not do anything that would cause 1157 * a page fault if we can help it. 1158 * 1159 * Specifically, we do not try to actually free 1160 * the page now nor do we try to put it in the 1161 * cache (which would cause a page fault on reuse). 1162 * 1163 * But we do make the page is freeable as we 1164 * can without actually taking the step of unmapping 1165 * it. 1166 */ 1167 pmap_clear_modify(m); 1168 m->dirty = 0; 1169 m->act_count = 0; 1170 vm_page_dontneed(m); 1171 } 1172 vm_page_unlock(m); 1173 if (advise == MADV_FREE && tobject->type == OBJT_SWAP) 1174 swap_pager_freespace(tobject, tpindex, 1); 1175 unlock_tobject: 1176 if (tobject != object) 1177 VM_OBJECT_UNLOCK(tobject); 1178 } 1179 VM_OBJECT_UNLOCK(object); 1180 } 1181 1182 /* 1183 * vm_object_shadow: 1184 * 1185 * Create a new object which is backed by the 1186 * specified existing object range. The source 1187 * object reference is deallocated. 1188 * 1189 * The new object and offset into that object 1190 * are returned in the source parameters. 1191 */ 1192 void 1193 vm_object_shadow( 1194 vm_object_t *object, /* IN/OUT */ 1195 vm_ooffset_t *offset, /* IN/OUT */ 1196 vm_size_t length) 1197 { 1198 vm_object_t source; 1199 vm_object_t result; 1200 1201 source = *object; 1202 1203 /* 1204 * Don't create the new object if the old object isn't shared. 1205 */ 1206 if (source != NULL) { 1207 VM_OBJECT_LOCK(source); 1208 if (source->ref_count == 1 && 1209 source->handle == NULL && 1210 (source->type == OBJT_DEFAULT || 1211 source->type == OBJT_SWAP)) { 1212 VM_OBJECT_UNLOCK(source); 1213 return; 1214 } 1215 VM_OBJECT_UNLOCK(source); 1216 } 1217 1218 /* 1219 * Allocate a new object with the given length. 1220 */ 1221 result = vm_object_allocate(OBJT_DEFAULT, atop(length)); 1222 1223 /* 1224 * The new object shadows the source object, adding a reference to it. 1225 * Our caller changes his reference to point to the new object, 1226 * removing a reference to the source object. Net result: no change 1227 * of reference count. 1228 * 1229 * Try to optimize the result object's page color when shadowing 1230 * in order to maintain page coloring consistency in the combined 1231 * shadowed object. 1232 */ 1233 result->backing_object = source; 1234 /* 1235 * Store the offset into the source object, and fix up the offset into 1236 * the new object. 1237 */ 1238 result->backing_object_offset = *offset; 1239 if (source != NULL) { 1240 VM_OBJECT_LOCK(source); 1241 LIST_INSERT_HEAD(&source->shadow_head, result, shadow_list); 1242 source->shadow_count++; 1243 #if VM_NRESERVLEVEL > 0 1244 result->flags |= source->flags & OBJ_COLORED; 1245 result->pg_color = (source->pg_color + OFF_TO_IDX(*offset)) & 1246 ((1 << (VM_NFREEORDER - 1)) - 1); 1247 #endif 1248 VM_OBJECT_UNLOCK(source); 1249 } 1250 1251 1252 /* 1253 * Return the new things 1254 */ 1255 *offset = 0; 1256 *object = result; 1257 } 1258 1259 /* 1260 * vm_object_split: 1261 * 1262 * Split the pages in a map entry into a new object. This affords 1263 * easier removal of unused pages, and keeps object inheritance from 1264 * being a negative impact on memory usage. 1265 */ 1266 void 1267 vm_object_split(vm_map_entry_t entry) 1268 { 1269 vm_page_t m, m_next; 1270 vm_object_t orig_object, new_object, source; 1271 vm_pindex_t idx, offidxstart; 1272 vm_size_t size; 1273 1274 orig_object = entry->object.vm_object; 1275 if (orig_object->type != OBJT_DEFAULT && orig_object->type != OBJT_SWAP) 1276 return; 1277 if (orig_object->ref_count <= 1) 1278 return; 1279 VM_OBJECT_UNLOCK(orig_object); 1280 1281 offidxstart = OFF_TO_IDX(entry->offset); 1282 size = atop(entry->end - entry->start); 1283 1284 /* 1285 * If swap_pager_copy() is later called, it will convert new_object 1286 * into a swap object. 1287 */ 1288 new_object = vm_object_allocate(OBJT_DEFAULT, size); 1289 1290 /* 1291 * At this point, the new object is still private, so the order in 1292 * which the original and new objects are locked does not matter. 1293 */ 1294 VM_OBJECT_LOCK(new_object); 1295 VM_OBJECT_LOCK(orig_object); 1296 source = orig_object->backing_object; 1297 if (source != NULL) { 1298 VM_OBJECT_LOCK(source); 1299 if ((source->flags & OBJ_DEAD) != 0) { 1300 VM_OBJECT_UNLOCK(source); 1301 VM_OBJECT_UNLOCK(orig_object); 1302 VM_OBJECT_UNLOCK(new_object); 1303 vm_object_deallocate(new_object); 1304 VM_OBJECT_LOCK(orig_object); 1305 return; 1306 } 1307 LIST_INSERT_HEAD(&source->shadow_head, 1308 new_object, shadow_list); 1309 source->shadow_count++; 1310 vm_object_reference_locked(source); /* for new_object */ 1311 vm_object_clear_flag(source, OBJ_ONEMAPPING); 1312 VM_OBJECT_UNLOCK(source); 1313 new_object->backing_object_offset = 1314 orig_object->backing_object_offset + entry->offset; 1315 new_object->backing_object = source; 1316 } 1317 if (orig_object->cred != NULL) { 1318 new_object->cred = orig_object->cred; 1319 crhold(orig_object->cred); 1320 new_object->charge = ptoa(size); 1321 KASSERT(orig_object->charge >= ptoa(size), 1322 ("orig_object->charge < 0")); 1323 orig_object->charge -= ptoa(size); 1324 } 1325 retry: 1326 m = vm_page_find_least(orig_object, offidxstart); 1327 for (; m != NULL && (idx = m->pindex - offidxstart) < size; 1328 m = m_next) { 1329 m_next = TAILQ_NEXT(m, listq); 1330 1331 /* 1332 * We must wait for pending I/O to complete before we can 1333 * rename the page. 1334 * 1335 * We do not have to VM_PROT_NONE the page as mappings should 1336 * not be changed by this operation. 1337 */ 1338 if ((m->oflags & VPO_BUSY) || m->busy) { 1339 VM_OBJECT_UNLOCK(new_object); 1340 m->oflags |= VPO_WANTED; 1341 msleep(m, VM_OBJECT_MTX(orig_object), PVM, "spltwt", 0); 1342 VM_OBJECT_LOCK(new_object); 1343 goto retry; 1344 } 1345 #if VM_NRESERVLEVEL > 0 1346 /* 1347 * If some of the reservation's allocated pages remain with 1348 * the original object, then transferring the reservation to 1349 * the new object is neither particularly beneficial nor 1350 * particularly harmful as compared to leaving the reservation 1351 * with the original object. If, however, all of the 1352 * reservation's allocated pages are transferred to the new 1353 * object, then transferring the reservation is typically 1354 * beneficial. Determining which of these two cases applies 1355 * would be more costly than unconditionally renaming the 1356 * reservation. 1357 */ 1358 vm_reserv_rename(m, new_object, orig_object, offidxstart); 1359 #endif 1360 vm_page_lock(m); 1361 vm_page_rename(m, new_object, idx); 1362 vm_page_unlock(m); 1363 /* page automatically made dirty by rename and cache handled */ 1364 vm_page_busy(m); 1365 } 1366 if (orig_object->type == OBJT_SWAP) { 1367 /* 1368 * swap_pager_copy() can sleep, in which case the orig_object's 1369 * and new_object's locks are released and reacquired. 1370 */ 1371 swap_pager_copy(orig_object, new_object, offidxstart, 0); 1372 1373 /* 1374 * Transfer any cached pages from orig_object to new_object. 1375 * If swap_pager_copy() found swapped out pages within the 1376 * specified range of orig_object, then it changed 1377 * new_object's type to OBJT_SWAP when it transferred those 1378 * pages to new_object. Otherwise, new_object's type 1379 * should still be OBJT_DEFAULT and orig_object should not 1380 * contain any cached pages within the specified range. 1381 */ 1382 if (__predict_false(orig_object->cache != NULL)) 1383 vm_page_cache_transfer(orig_object, offidxstart, 1384 new_object); 1385 } 1386 VM_OBJECT_UNLOCK(orig_object); 1387 TAILQ_FOREACH(m, &new_object->memq, listq) 1388 vm_page_wakeup(m); 1389 VM_OBJECT_UNLOCK(new_object); 1390 entry->object.vm_object = new_object; 1391 entry->offset = 0LL; 1392 vm_object_deallocate(orig_object); 1393 VM_OBJECT_LOCK(new_object); 1394 } 1395 1396 #define OBSC_TEST_ALL_SHADOWED 0x0001 1397 #define OBSC_COLLAPSE_NOWAIT 0x0002 1398 #define OBSC_COLLAPSE_WAIT 0x0004 1399 1400 static int 1401 vm_object_backing_scan(vm_object_t object, int op) 1402 { 1403 int r = 1; 1404 vm_page_t p; 1405 vm_object_t backing_object; 1406 vm_pindex_t backing_offset_index; 1407 1408 VM_OBJECT_LOCK_ASSERT(object, MA_OWNED); 1409 VM_OBJECT_LOCK_ASSERT(object->backing_object, MA_OWNED); 1410 1411 backing_object = object->backing_object; 1412 backing_offset_index = OFF_TO_IDX(object->backing_object_offset); 1413 1414 /* 1415 * Initial conditions 1416 */ 1417 if (op & OBSC_TEST_ALL_SHADOWED) { 1418 /* 1419 * We do not want to have to test for the existence of cache 1420 * or swap pages in the backing object. XXX but with the 1421 * new swapper this would be pretty easy to do. 1422 * 1423 * XXX what about anonymous MAP_SHARED memory that hasn't 1424 * been ZFOD faulted yet? If we do not test for this, the 1425 * shadow test may succeed! XXX 1426 */ 1427 if (backing_object->type != OBJT_DEFAULT) { 1428 return (0); 1429 } 1430 } 1431 if (op & OBSC_COLLAPSE_WAIT) { 1432 vm_object_set_flag(backing_object, OBJ_DEAD); 1433 } 1434 1435 /* 1436 * Our scan 1437 */ 1438 p = TAILQ_FIRST(&backing_object->memq); 1439 while (p) { 1440 vm_page_t next = TAILQ_NEXT(p, listq); 1441 vm_pindex_t new_pindex = p->pindex - backing_offset_index; 1442 1443 if (op & OBSC_TEST_ALL_SHADOWED) { 1444 vm_page_t pp; 1445 1446 /* 1447 * Ignore pages outside the parent object's range 1448 * and outside the parent object's mapping of the 1449 * backing object. 1450 * 1451 * note that we do not busy the backing object's 1452 * page. 1453 */ 1454 if ( 1455 p->pindex < backing_offset_index || 1456 new_pindex >= object->size 1457 ) { 1458 p = next; 1459 continue; 1460 } 1461 1462 /* 1463 * See if the parent has the page or if the parent's 1464 * object pager has the page. If the parent has the 1465 * page but the page is not valid, the parent's 1466 * object pager must have the page. 1467 * 1468 * If this fails, the parent does not completely shadow 1469 * the object and we might as well give up now. 1470 */ 1471 1472 pp = vm_page_lookup(object, new_pindex); 1473 if ( 1474 (pp == NULL || pp->valid == 0) && 1475 !vm_pager_has_page(object, new_pindex, NULL, NULL) 1476 ) { 1477 r = 0; 1478 break; 1479 } 1480 } 1481 1482 /* 1483 * Check for busy page 1484 */ 1485 if (op & (OBSC_COLLAPSE_WAIT | OBSC_COLLAPSE_NOWAIT)) { 1486 vm_page_t pp; 1487 1488 if (op & OBSC_COLLAPSE_NOWAIT) { 1489 if ((p->oflags & VPO_BUSY) || 1490 !p->valid || 1491 p->busy) { 1492 p = next; 1493 continue; 1494 } 1495 } else if (op & OBSC_COLLAPSE_WAIT) { 1496 if ((p->oflags & VPO_BUSY) || p->busy) { 1497 VM_OBJECT_UNLOCK(object); 1498 p->oflags |= VPO_WANTED; 1499 msleep(p, VM_OBJECT_MTX(backing_object), 1500 PDROP | PVM, "vmocol", 0); 1501 VM_OBJECT_LOCK(object); 1502 VM_OBJECT_LOCK(backing_object); 1503 /* 1504 * If we slept, anything could have 1505 * happened. Since the object is 1506 * marked dead, the backing offset 1507 * should not have changed so we 1508 * just restart our scan. 1509 */ 1510 p = TAILQ_FIRST(&backing_object->memq); 1511 continue; 1512 } 1513 } 1514 1515 KASSERT( 1516 p->object == backing_object, 1517 ("vm_object_backing_scan: object mismatch") 1518 ); 1519 1520 /* 1521 * Destroy any associated swap 1522 */ 1523 if (backing_object->type == OBJT_SWAP) { 1524 swap_pager_freespace( 1525 backing_object, 1526 p->pindex, 1527 1 1528 ); 1529 } 1530 1531 if ( 1532 p->pindex < backing_offset_index || 1533 new_pindex >= object->size 1534 ) { 1535 /* 1536 * Page is out of the parent object's range, we 1537 * can simply destroy it. 1538 */ 1539 vm_page_lock(p); 1540 KASSERT(!pmap_page_is_mapped(p), 1541 ("freeing mapped page %p", p)); 1542 if (p->wire_count == 0) 1543 vm_page_free(p); 1544 else 1545 vm_page_remove(p); 1546 vm_page_unlock(p); 1547 p = next; 1548 continue; 1549 } 1550 1551 pp = vm_page_lookup(object, new_pindex); 1552 if ( 1553 (op & OBSC_COLLAPSE_NOWAIT) != 0 && 1554 (pp != NULL && pp->valid == 0) 1555 ) { 1556 /* 1557 * The page in the parent is not (yet) valid. 1558 * We don't know anything about the state of 1559 * the original page. It might be mapped, 1560 * so we must avoid the next if here. 1561 * 1562 * This is due to a race in vm_fault() where 1563 * we must unbusy the original (backing_obj) 1564 * page before we can (re)lock the parent. 1565 * Hence we can get here. 1566 */ 1567 p = next; 1568 continue; 1569 } 1570 if ( 1571 pp != NULL || 1572 vm_pager_has_page(object, new_pindex, NULL, NULL) 1573 ) { 1574 /* 1575 * page already exists in parent OR swap exists 1576 * for this location in the parent. Destroy 1577 * the original page from the backing object. 1578 * 1579 * Leave the parent's page alone 1580 */ 1581 vm_page_lock(p); 1582 KASSERT(!pmap_page_is_mapped(p), 1583 ("freeing mapped page %p", p)); 1584 if (p->wire_count == 0) 1585 vm_page_free(p); 1586 else 1587 vm_page_remove(p); 1588 vm_page_unlock(p); 1589 p = next; 1590 continue; 1591 } 1592 1593 #if VM_NRESERVLEVEL > 0 1594 /* 1595 * Rename the reservation. 1596 */ 1597 vm_reserv_rename(p, object, backing_object, 1598 backing_offset_index); 1599 #endif 1600 1601 /* 1602 * Page does not exist in parent, rename the 1603 * page from the backing object to the main object. 1604 * 1605 * If the page was mapped to a process, it can remain 1606 * mapped through the rename. 1607 */ 1608 vm_page_lock(p); 1609 vm_page_rename(p, object, new_pindex); 1610 vm_page_unlock(p); 1611 /* page automatically made dirty by rename */ 1612 } 1613 p = next; 1614 } 1615 return (r); 1616 } 1617 1618 1619 /* 1620 * this version of collapse allows the operation to occur earlier and 1621 * when paging_in_progress is true for an object... This is not a complete 1622 * operation, but should plug 99.9% of the rest of the leaks. 1623 */ 1624 static void 1625 vm_object_qcollapse(vm_object_t object) 1626 { 1627 vm_object_t backing_object = object->backing_object; 1628 1629 VM_OBJECT_LOCK_ASSERT(object, MA_OWNED); 1630 VM_OBJECT_LOCK_ASSERT(backing_object, MA_OWNED); 1631 1632 if (backing_object->ref_count != 1) 1633 return; 1634 1635 vm_object_backing_scan(object, OBSC_COLLAPSE_NOWAIT); 1636 } 1637 1638 /* 1639 * vm_object_collapse: 1640 * 1641 * Collapse an object with the object backing it. 1642 * Pages in the backing object are moved into the 1643 * parent, and the backing object is deallocated. 1644 */ 1645 void 1646 vm_object_collapse(vm_object_t object) 1647 { 1648 VM_OBJECT_LOCK_ASSERT(object, MA_OWNED); 1649 1650 while (TRUE) { 1651 vm_object_t backing_object; 1652 1653 /* 1654 * Verify that the conditions are right for collapse: 1655 * 1656 * The object exists and the backing object exists. 1657 */ 1658 if ((backing_object = object->backing_object) == NULL) 1659 break; 1660 1661 /* 1662 * we check the backing object first, because it is most likely 1663 * not collapsable. 1664 */ 1665 VM_OBJECT_LOCK(backing_object); 1666 if (backing_object->handle != NULL || 1667 (backing_object->type != OBJT_DEFAULT && 1668 backing_object->type != OBJT_SWAP) || 1669 (backing_object->flags & OBJ_DEAD) || 1670 object->handle != NULL || 1671 (object->type != OBJT_DEFAULT && 1672 object->type != OBJT_SWAP) || 1673 (object->flags & OBJ_DEAD)) { 1674 VM_OBJECT_UNLOCK(backing_object); 1675 break; 1676 } 1677 1678 if ( 1679 object->paging_in_progress != 0 || 1680 backing_object->paging_in_progress != 0 1681 ) { 1682 vm_object_qcollapse(object); 1683 VM_OBJECT_UNLOCK(backing_object); 1684 break; 1685 } 1686 /* 1687 * We know that we can either collapse the backing object (if 1688 * the parent is the only reference to it) or (perhaps) have 1689 * the parent bypass the object if the parent happens to shadow 1690 * all the resident pages in the entire backing object. 1691 * 1692 * This is ignoring pager-backed pages such as swap pages. 1693 * vm_object_backing_scan fails the shadowing test in this 1694 * case. 1695 */ 1696 if (backing_object->ref_count == 1) { 1697 /* 1698 * If there is exactly one reference to the backing 1699 * object, we can collapse it into the parent. 1700 */ 1701 vm_object_backing_scan(object, OBSC_COLLAPSE_WAIT); 1702 1703 #if VM_NRESERVLEVEL > 0 1704 /* 1705 * Break any reservations from backing_object. 1706 */ 1707 if (__predict_false(!LIST_EMPTY(&backing_object->rvq))) 1708 vm_reserv_break_all(backing_object); 1709 #endif 1710 1711 /* 1712 * Move the pager from backing_object to object. 1713 */ 1714 if (backing_object->type == OBJT_SWAP) { 1715 /* 1716 * swap_pager_copy() can sleep, in which case 1717 * the backing_object's and object's locks are 1718 * released and reacquired. 1719 * Since swap_pager_copy() is being asked to 1720 * destroy the source, it will change the 1721 * backing_object's type to OBJT_DEFAULT. 1722 */ 1723 swap_pager_copy( 1724 backing_object, 1725 object, 1726 OFF_TO_IDX(object->backing_object_offset), TRUE); 1727 1728 /* 1729 * Free any cached pages from backing_object. 1730 */ 1731 if (__predict_false(backing_object->cache != NULL)) 1732 vm_page_cache_free(backing_object, 0, 0); 1733 } 1734 /* 1735 * Object now shadows whatever backing_object did. 1736 * Note that the reference to 1737 * backing_object->backing_object moves from within 1738 * backing_object to within object. 1739 */ 1740 LIST_REMOVE(object, shadow_list); 1741 backing_object->shadow_count--; 1742 if (backing_object->backing_object) { 1743 VM_OBJECT_LOCK(backing_object->backing_object); 1744 LIST_REMOVE(backing_object, shadow_list); 1745 LIST_INSERT_HEAD( 1746 &backing_object->backing_object->shadow_head, 1747 object, shadow_list); 1748 /* 1749 * The shadow_count has not changed. 1750 */ 1751 VM_OBJECT_UNLOCK(backing_object->backing_object); 1752 } 1753 object->backing_object = backing_object->backing_object; 1754 object->backing_object_offset += 1755 backing_object->backing_object_offset; 1756 1757 /* 1758 * Discard backing_object. 1759 * 1760 * Since the backing object has no pages, no pager left, 1761 * and no object references within it, all that is 1762 * necessary is to dispose of it. 1763 */ 1764 KASSERT(backing_object->ref_count == 1, ( 1765 "backing_object %p was somehow re-referenced during collapse!", 1766 backing_object)); 1767 VM_OBJECT_UNLOCK(backing_object); 1768 vm_object_destroy(backing_object); 1769 1770 object_collapses++; 1771 } else { 1772 vm_object_t new_backing_object; 1773 1774 /* 1775 * If we do not entirely shadow the backing object, 1776 * there is nothing we can do so we give up. 1777 */ 1778 if (object->resident_page_count != object->size && 1779 vm_object_backing_scan(object, 1780 OBSC_TEST_ALL_SHADOWED) == 0) { 1781 VM_OBJECT_UNLOCK(backing_object); 1782 break; 1783 } 1784 1785 /* 1786 * Make the parent shadow the next object in the 1787 * chain. Deallocating backing_object will not remove 1788 * it, since its reference count is at least 2. 1789 */ 1790 LIST_REMOVE(object, shadow_list); 1791 backing_object->shadow_count--; 1792 1793 new_backing_object = backing_object->backing_object; 1794 if ((object->backing_object = new_backing_object) != NULL) { 1795 VM_OBJECT_LOCK(new_backing_object); 1796 LIST_INSERT_HEAD( 1797 &new_backing_object->shadow_head, 1798 object, 1799 shadow_list 1800 ); 1801 new_backing_object->shadow_count++; 1802 vm_object_reference_locked(new_backing_object); 1803 VM_OBJECT_UNLOCK(new_backing_object); 1804 object->backing_object_offset += 1805 backing_object->backing_object_offset; 1806 } 1807 1808 /* 1809 * Drop the reference count on backing_object. Since 1810 * its ref_count was at least 2, it will not vanish. 1811 */ 1812 backing_object->ref_count--; 1813 VM_OBJECT_UNLOCK(backing_object); 1814 object_bypasses++; 1815 } 1816 1817 /* 1818 * Try again with this object's new backing object. 1819 */ 1820 } 1821 } 1822 1823 /* 1824 * vm_object_page_remove: 1825 * 1826 * For the given object, either frees or invalidates each of the 1827 * specified pages. In general, a page is freed. However, if a page is 1828 * wired for any reason other than the existence of a managed, wired 1829 * mapping, then it may be invalidated but not removed from the object. 1830 * Pages are specified by the given range ["start", "end") and the option 1831 * OBJPR_CLEANONLY. As a special case, if "end" is zero, then the range 1832 * extends from "start" to the end of the object. If the option 1833 * OBJPR_CLEANONLY is specified, then only the non-dirty pages within the 1834 * specified range are affected. If the option OBJPR_NOTMAPPED is 1835 * specified, then the pages within the specified range must have no 1836 * mappings. Otherwise, if this option is not specified, any mappings to 1837 * the specified pages are removed before the pages are freed or 1838 * invalidated. 1839 * 1840 * In general, this operation should only be performed on objects that 1841 * contain managed pages. There are, however, two exceptions. First, it 1842 * is performed on the kernel and kmem objects by vm_map_entry_delete(). 1843 * Second, it is used by msync(..., MS_INVALIDATE) to invalidate device- 1844 * backed pages. In both of these cases, the option OBJPR_CLEANONLY must 1845 * not be specified and the option OBJPR_NOTMAPPED must be specified. 1846 * 1847 * The object must be locked. 1848 */ 1849 void 1850 vm_object_page_remove(vm_object_t object, vm_pindex_t start, vm_pindex_t end, 1851 int options) 1852 { 1853 vm_page_t p, next; 1854 int wirings; 1855 1856 VM_OBJECT_LOCK_ASSERT(object, MA_OWNED); 1857 KASSERT((object->flags & OBJ_UNMANAGED) == 0 || 1858 (options & (OBJPR_CLEANONLY | OBJPR_NOTMAPPED)) == OBJPR_NOTMAPPED, 1859 ("vm_object_page_remove: illegal options for object %p", object)); 1860 if (object->resident_page_count == 0) 1861 goto skipmemq; 1862 vm_object_pip_add(object, 1); 1863 again: 1864 p = vm_page_find_least(object, start); 1865 1866 /* 1867 * Here, the variable "p" is either (1) the page with the least pindex 1868 * greater than or equal to the parameter "start" or (2) NULL. 1869 */ 1870 for (; p != NULL && (p->pindex < end || end == 0); p = next) { 1871 next = TAILQ_NEXT(p, listq); 1872 1873 /* 1874 * If the page is wired for any reason besides the existence 1875 * of managed, wired mappings, then it cannot be freed. For 1876 * example, fictitious pages, which represent device memory, 1877 * are inherently wired and cannot be freed. They can, 1878 * however, be invalidated if the option OBJPR_CLEANONLY is 1879 * not specified. 1880 */ 1881 vm_page_lock(p); 1882 if ((wirings = p->wire_count) != 0 && 1883 (wirings = pmap_page_wired_mappings(p)) != p->wire_count) { 1884 if ((options & OBJPR_NOTMAPPED) == 0) { 1885 pmap_remove_all(p); 1886 /* Account for removal of wired mappings. */ 1887 if (wirings != 0) 1888 p->wire_count -= wirings; 1889 } 1890 if ((options & OBJPR_CLEANONLY) == 0) { 1891 p->valid = 0; 1892 vm_page_undirty(p); 1893 } 1894 vm_page_unlock(p); 1895 continue; 1896 } 1897 if (vm_page_sleep_if_busy(p, TRUE, "vmopar")) 1898 goto again; 1899 KASSERT((p->flags & PG_FICTITIOUS) == 0, 1900 ("vm_object_page_remove: page %p is fictitious", p)); 1901 if ((options & OBJPR_CLEANONLY) != 0 && p->valid != 0) { 1902 if ((options & OBJPR_NOTMAPPED) == 0) 1903 pmap_remove_write(p); 1904 if (p->dirty) { 1905 vm_page_unlock(p); 1906 continue; 1907 } 1908 } 1909 if ((options & OBJPR_NOTMAPPED) == 0) { 1910 pmap_remove_all(p); 1911 /* Account for removal of wired mappings. */ 1912 if (wirings != 0) { 1913 KASSERT(p->wire_count == wirings, 1914 ("inconsistent wire count %d %d %p", 1915 p->wire_count, wirings, p)); 1916 p->wire_count = 0; 1917 atomic_subtract_int(&cnt.v_wire_count, 1); 1918 } 1919 } 1920 vm_page_free(p); 1921 vm_page_unlock(p); 1922 } 1923 vm_object_pip_wakeup(object); 1924 skipmemq: 1925 if (__predict_false(object->cache != NULL)) 1926 vm_page_cache_free(object, start, end); 1927 } 1928 1929 /* 1930 * vm_object_page_cache: 1931 * 1932 * For the given object, attempt to move the specified clean 1933 * pages to the cache queue. If a page is wired for any reason, 1934 * then it will not be changed. Pages are specified by the given 1935 * range ["start", "end"). As a special case, if "end" is zero, 1936 * then the range extends from "start" to the end of the object. 1937 * Any mappings to the specified pages are removed before the 1938 * pages are moved to the cache queue. 1939 * 1940 * This operation should only be performed on objects that 1941 * contain non-fictitious, managed pages. 1942 * 1943 * The object must be locked. 1944 */ 1945 void 1946 vm_object_page_cache(vm_object_t object, vm_pindex_t start, vm_pindex_t end) 1947 { 1948 struct mtx *mtx, *new_mtx; 1949 vm_page_t p, next; 1950 1951 VM_OBJECT_LOCK_ASSERT(object, MA_OWNED); 1952 KASSERT((object->flags & (OBJ_FICTITIOUS | OBJ_UNMANAGED)) == 0, 1953 ("vm_object_page_cache: illegal object %p", object)); 1954 if (object->resident_page_count == 0) 1955 return; 1956 p = vm_page_find_least(object, start); 1957 1958 /* 1959 * Here, the variable "p" is either (1) the page with the least pindex 1960 * greater than or equal to the parameter "start" or (2) NULL. 1961 */ 1962 mtx = NULL; 1963 for (; p != NULL && (p->pindex < end || end == 0); p = next) { 1964 next = TAILQ_NEXT(p, listq); 1965 1966 /* 1967 * Avoid releasing and reacquiring the same page lock. 1968 */ 1969 new_mtx = vm_page_lockptr(p); 1970 if (mtx != new_mtx) { 1971 if (mtx != NULL) 1972 mtx_unlock(mtx); 1973 mtx = new_mtx; 1974 mtx_lock(mtx); 1975 } 1976 vm_page_try_to_cache(p); 1977 } 1978 if (mtx != NULL) 1979 mtx_unlock(mtx); 1980 } 1981 1982 /* 1983 * Populate the specified range of the object with valid pages. Returns 1984 * TRUE if the range is successfully populated and FALSE otherwise. 1985 * 1986 * Note: This function should be optimized to pass a larger array of 1987 * pages to vm_pager_get_pages() before it is applied to a non- 1988 * OBJT_DEVICE object. 1989 * 1990 * The object must be locked. 1991 */ 1992 boolean_t 1993 vm_object_populate(vm_object_t object, vm_pindex_t start, vm_pindex_t end) 1994 { 1995 vm_page_t m, ma[1]; 1996 vm_pindex_t pindex; 1997 int rv; 1998 1999 VM_OBJECT_LOCK_ASSERT(object, MA_OWNED); 2000 for (pindex = start; pindex < end; pindex++) { 2001 m = vm_page_grab(object, pindex, VM_ALLOC_NORMAL | 2002 VM_ALLOC_RETRY); 2003 if (m->valid != VM_PAGE_BITS_ALL) { 2004 ma[0] = m; 2005 rv = vm_pager_get_pages(object, ma, 1, 0); 2006 m = vm_page_lookup(object, pindex); 2007 if (m == NULL) 2008 break; 2009 if (rv != VM_PAGER_OK) { 2010 vm_page_lock(m); 2011 vm_page_free(m); 2012 vm_page_unlock(m); 2013 break; 2014 } 2015 } 2016 /* 2017 * Keep "m" busy because a subsequent iteration may unlock 2018 * the object. 2019 */ 2020 } 2021 if (pindex > start) { 2022 m = vm_page_lookup(object, start); 2023 while (m != NULL && m->pindex < pindex) { 2024 vm_page_wakeup(m); 2025 m = TAILQ_NEXT(m, listq); 2026 } 2027 } 2028 return (pindex == end); 2029 } 2030 2031 /* 2032 * Routine: vm_object_coalesce 2033 * Function: Coalesces two objects backing up adjoining 2034 * regions of memory into a single object. 2035 * 2036 * returns TRUE if objects were combined. 2037 * 2038 * NOTE: Only works at the moment if the second object is NULL - 2039 * if it's not, which object do we lock first? 2040 * 2041 * Parameters: 2042 * prev_object First object to coalesce 2043 * prev_offset Offset into prev_object 2044 * prev_size Size of reference to prev_object 2045 * next_size Size of reference to the second object 2046 * reserved Indicator that extension region has 2047 * swap accounted for 2048 * 2049 * Conditions: 2050 * The object must *not* be locked. 2051 */ 2052 boolean_t 2053 vm_object_coalesce(vm_object_t prev_object, vm_ooffset_t prev_offset, 2054 vm_size_t prev_size, vm_size_t next_size, boolean_t reserved) 2055 { 2056 vm_pindex_t next_pindex; 2057 2058 if (prev_object == NULL) 2059 return (TRUE); 2060 VM_OBJECT_LOCK(prev_object); 2061 if (prev_object->type != OBJT_DEFAULT && 2062 prev_object->type != OBJT_SWAP) { 2063 VM_OBJECT_UNLOCK(prev_object); 2064 return (FALSE); 2065 } 2066 2067 /* 2068 * Try to collapse the object first 2069 */ 2070 vm_object_collapse(prev_object); 2071 2072 /* 2073 * Can't coalesce if: . more than one reference . paged out . shadows 2074 * another object . has a copy elsewhere (any of which mean that the 2075 * pages not mapped to prev_entry may be in use anyway) 2076 */ 2077 if (prev_object->backing_object != NULL) { 2078 VM_OBJECT_UNLOCK(prev_object); 2079 return (FALSE); 2080 } 2081 2082 prev_size >>= PAGE_SHIFT; 2083 next_size >>= PAGE_SHIFT; 2084 next_pindex = OFF_TO_IDX(prev_offset) + prev_size; 2085 2086 if ((prev_object->ref_count > 1) && 2087 (prev_object->size != next_pindex)) { 2088 VM_OBJECT_UNLOCK(prev_object); 2089 return (FALSE); 2090 } 2091 2092 /* 2093 * Account for the charge. 2094 */ 2095 if (prev_object->cred != NULL) { 2096 2097 /* 2098 * If prev_object was charged, then this mapping, 2099 * althought not charged now, may become writable 2100 * later. Non-NULL cred in the object would prevent 2101 * swap reservation during enabling of the write 2102 * access, so reserve swap now. Failed reservation 2103 * cause allocation of the separate object for the map 2104 * entry, and swap reservation for this entry is 2105 * managed in appropriate time. 2106 */ 2107 if (!reserved && !swap_reserve_by_cred(ptoa(next_size), 2108 prev_object->cred)) { 2109 return (FALSE); 2110 } 2111 prev_object->charge += ptoa(next_size); 2112 } 2113 2114 /* 2115 * Remove any pages that may still be in the object from a previous 2116 * deallocation. 2117 */ 2118 if (next_pindex < prev_object->size) { 2119 vm_object_page_remove(prev_object, next_pindex, next_pindex + 2120 next_size, 0); 2121 if (prev_object->type == OBJT_SWAP) 2122 swap_pager_freespace(prev_object, 2123 next_pindex, next_size); 2124 #if 0 2125 if (prev_object->cred != NULL) { 2126 KASSERT(prev_object->charge >= 2127 ptoa(prev_object->size - next_pindex), 2128 ("object %p overcharged 1 %jx %jx", prev_object, 2129 (uintmax_t)next_pindex, (uintmax_t)next_size)); 2130 prev_object->charge -= ptoa(prev_object->size - 2131 next_pindex); 2132 } 2133 #endif 2134 } 2135 2136 /* 2137 * Extend the object if necessary. 2138 */ 2139 if (next_pindex + next_size > prev_object->size) 2140 prev_object->size = next_pindex + next_size; 2141 2142 VM_OBJECT_UNLOCK(prev_object); 2143 return (TRUE); 2144 } 2145 2146 void 2147 vm_object_set_writeable_dirty(vm_object_t object) 2148 { 2149 2150 VM_OBJECT_LOCK_ASSERT(object, MA_OWNED); 2151 if (object->type != OBJT_VNODE) 2152 return; 2153 object->generation++; 2154 if ((object->flags & OBJ_MIGHTBEDIRTY) != 0) 2155 return; 2156 vm_object_set_flag(object, OBJ_MIGHTBEDIRTY); 2157 } 2158 2159 #include "opt_ddb.h" 2160 #ifdef DDB 2161 #include <sys/kernel.h> 2162 2163 #include <sys/cons.h> 2164 2165 #include <ddb/ddb.h> 2166 2167 static int 2168 _vm_object_in_map(vm_map_t map, vm_object_t object, vm_map_entry_t entry) 2169 { 2170 vm_map_t tmpm; 2171 vm_map_entry_t tmpe; 2172 vm_object_t obj; 2173 int entcount; 2174 2175 if (map == 0) 2176 return 0; 2177 2178 if (entry == 0) { 2179 tmpe = map->header.next; 2180 entcount = map->nentries; 2181 while (entcount-- && (tmpe != &map->header)) { 2182 if (_vm_object_in_map(map, object, tmpe)) { 2183 return 1; 2184 } 2185 tmpe = tmpe->next; 2186 } 2187 } else if (entry->eflags & MAP_ENTRY_IS_SUB_MAP) { 2188 tmpm = entry->object.sub_map; 2189 tmpe = tmpm->header.next; 2190 entcount = tmpm->nentries; 2191 while (entcount-- && tmpe != &tmpm->header) { 2192 if (_vm_object_in_map(tmpm, object, tmpe)) { 2193 return 1; 2194 } 2195 tmpe = tmpe->next; 2196 } 2197 } else if ((obj = entry->object.vm_object) != NULL) { 2198 for (; obj; obj = obj->backing_object) 2199 if (obj == object) { 2200 return 1; 2201 } 2202 } 2203 return 0; 2204 } 2205 2206 static int 2207 vm_object_in_map(vm_object_t object) 2208 { 2209 struct proc *p; 2210 2211 /* sx_slock(&allproc_lock); */ 2212 FOREACH_PROC_IN_SYSTEM(p) { 2213 if (!p->p_vmspace /* || (p->p_flag & (P_SYSTEM|P_WEXIT)) */) 2214 continue; 2215 if (_vm_object_in_map(&p->p_vmspace->vm_map, object, 0)) { 2216 /* sx_sunlock(&allproc_lock); */ 2217 return 1; 2218 } 2219 } 2220 /* sx_sunlock(&allproc_lock); */ 2221 if (_vm_object_in_map(kernel_map, object, 0)) 2222 return 1; 2223 if (_vm_object_in_map(kmem_map, object, 0)) 2224 return 1; 2225 if (_vm_object_in_map(pager_map, object, 0)) 2226 return 1; 2227 if (_vm_object_in_map(buffer_map, object, 0)) 2228 return 1; 2229 return 0; 2230 } 2231 2232 DB_SHOW_COMMAND(vmochk, vm_object_check) 2233 { 2234 vm_object_t object; 2235 2236 /* 2237 * make sure that internal objs are in a map somewhere 2238 * and none have zero ref counts. 2239 */ 2240 TAILQ_FOREACH(object, &vm_object_list, object_list) { 2241 if (object->handle == NULL && 2242 (object->type == OBJT_DEFAULT || object->type == OBJT_SWAP)) { 2243 if (object->ref_count == 0) { 2244 db_printf("vmochk: internal obj has zero ref count: %ld\n", 2245 (long)object->size); 2246 } 2247 if (!vm_object_in_map(object)) { 2248 db_printf( 2249 "vmochk: internal obj is not in a map: " 2250 "ref: %d, size: %lu: 0x%lx, backing_object: %p\n", 2251 object->ref_count, (u_long)object->size, 2252 (u_long)object->size, 2253 (void *)object->backing_object); 2254 } 2255 } 2256 } 2257 } 2258 2259 /* 2260 * vm_object_print: [ debug ] 2261 */ 2262 DB_SHOW_COMMAND(object, vm_object_print_static) 2263 { 2264 /* XXX convert args. */ 2265 vm_object_t object = (vm_object_t)addr; 2266 boolean_t full = have_addr; 2267 2268 vm_page_t p; 2269 2270 /* XXX count is an (unused) arg. Avoid shadowing it. */ 2271 #define count was_count 2272 2273 int count; 2274 2275 if (object == NULL) 2276 return; 2277 2278 db_iprintf( 2279 "Object %p: type=%d, size=0x%jx, res=%d, ref=%d, flags=0x%x ruid %d charge %jx\n", 2280 object, (int)object->type, (uintmax_t)object->size, 2281 object->resident_page_count, object->ref_count, object->flags, 2282 object->cred ? object->cred->cr_ruid : -1, (uintmax_t)object->charge); 2283 db_iprintf(" sref=%d, backing_object(%d)=(%p)+0x%jx\n", 2284 object->shadow_count, 2285 object->backing_object ? object->backing_object->ref_count : 0, 2286 object->backing_object, (uintmax_t)object->backing_object_offset); 2287 2288 if (!full) 2289 return; 2290 2291 db_indent += 2; 2292 count = 0; 2293 TAILQ_FOREACH(p, &object->memq, listq) { 2294 if (count == 0) 2295 db_iprintf("memory:="); 2296 else if (count == 6) { 2297 db_printf("\n"); 2298 db_iprintf(" ..."); 2299 count = 0; 2300 } else 2301 db_printf(","); 2302 count++; 2303 2304 db_printf("(off=0x%jx,page=0x%jx)", 2305 (uintmax_t)p->pindex, (uintmax_t)VM_PAGE_TO_PHYS(p)); 2306 } 2307 if (count != 0) 2308 db_printf("\n"); 2309 db_indent -= 2; 2310 } 2311 2312 /* XXX. */ 2313 #undef count 2314 2315 /* XXX need this non-static entry for calling from vm_map_print. */ 2316 void 2317 vm_object_print( 2318 /* db_expr_t */ long addr, 2319 boolean_t have_addr, 2320 /* db_expr_t */ long count, 2321 char *modif) 2322 { 2323 vm_object_print_static(addr, have_addr, count, modif); 2324 } 2325 2326 DB_SHOW_COMMAND(vmopag, vm_object_print_pages) 2327 { 2328 vm_object_t object; 2329 vm_pindex_t fidx; 2330 vm_paddr_t pa; 2331 vm_page_t m, prev_m; 2332 int rcount, nl, c; 2333 2334 nl = 0; 2335 TAILQ_FOREACH(object, &vm_object_list, object_list) { 2336 db_printf("new object: %p\n", (void *)object); 2337 if (nl > 18) { 2338 c = cngetc(); 2339 if (c != ' ') 2340 return; 2341 nl = 0; 2342 } 2343 nl++; 2344 rcount = 0; 2345 fidx = 0; 2346 pa = -1; 2347 TAILQ_FOREACH(m, &object->memq, listq) { 2348 if (m->pindex > 128) 2349 break; 2350 if ((prev_m = TAILQ_PREV(m, pglist, listq)) != NULL && 2351 prev_m->pindex + 1 != m->pindex) { 2352 if (rcount) { 2353 db_printf(" index(%ld)run(%d)pa(0x%lx)\n", 2354 (long)fidx, rcount, (long)pa); 2355 if (nl > 18) { 2356 c = cngetc(); 2357 if (c != ' ') 2358 return; 2359 nl = 0; 2360 } 2361 nl++; 2362 rcount = 0; 2363 } 2364 } 2365 if (rcount && 2366 (VM_PAGE_TO_PHYS(m) == pa + rcount * PAGE_SIZE)) { 2367 ++rcount; 2368 continue; 2369 } 2370 if (rcount) { 2371 db_printf(" index(%ld)run(%d)pa(0x%lx)\n", 2372 (long)fidx, rcount, (long)pa); 2373 if (nl > 18) { 2374 c = cngetc(); 2375 if (c != ' ') 2376 return; 2377 nl = 0; 2378 } 2379 nl++; 2380 } 2381 fidx = m->pindex; 2382 pa = VM_PAGE_TO_PHYS(m); 2383 rcount = 1; 2384 } 2385 if (rcount) { 2386 db_printf(" index(%ld)run(%d)pa(0x%lx)\n", 2387 (long)fidx, rcount, (long)pa); 2388 if (nl > 18) { 2389 c = cngetc(); 2390 if (c != ' ') 2391 return; 2392 nl = 0; 2393 } 2394 nl++; 2395 } 2396 } 2397 } 2398 #endif /* DDB */ 2399