1 /*- 2 * SPDX-License-Identifier: (BSD-3-Clause AND MIT-CMU) 3 * 4 * Copyright (c) 1991, 1993 5 * The Regents of the University of California. All rights reserved. 6 * 7 * This code is derived from software contributed to Berkeley by 8 * The Mach Operating System project at Carnegie-Mellon University. 9 * 10 * Redistribution and use in source and binary forms, with or without 11 * modification, are permitted provided that the following conditions 12 * are met: 13 * 1. Redistributions of source code must retain the above copyright 14 * notice, this list of conditions and the following disclaimer. 15 * 2. Redistributions in binary form must reproduce the above copyright 16 * notice, this list of conditions and the following disclaimer in the 17 * documentation and/or other materials provided with the distribution. 18 * 3. Neither the name of the University nor the names of its contributors 19 * may be used to endorse or promote products derived from this software 20 * without specific prior written permission. 21 * 22 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 23 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 24 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 25 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 26 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 27 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 28 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 29 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 30 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 31 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 32 * SUCH DAMAGE. 33 * 34 * from: @(#)vm_object.c 8.5 (Berkeley) 3/22/94 35 * 36 * 37 * Copyright (c) 1987, 1990 Carnegie-Mellon University. 38 * All rights reserved. 39 * 40 * Authors: Avadis Tevanian, Jr., Michael Wayne Young 41 * 42 * Permission to use, copy, modify and distribute this software and 43 * its documentation is hereby granted, provided that both the copyright 44 * notice and this permission notice appear in all copies of the 45 * software, derivative works or modified versions, and any portions 46 * thereof, and that both notices appear in supporting documentation. 47 * 48 * CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS" 49 * CONDITION. CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND 50 * FOR ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE. 51 * 52 * Carnegie Mellon requests users of this software to return to 53 * 54 * Software Distribution Coordinator or Software.Distribution@CS.CMU.EDU 55 * School of Computer Science 56 * Carnegie Mellon University 57 * Pittsburgh PA 15213-3890 58 * 59 * any improvements or extensions that they make and grant Carnegie the 60 * rights to redistribute these changes. 61 */ 62 63 /* 64 * Virtual memory object module. 65 */ 66 67 #include <sys/cdefs.h> 68 __FBSDID("$FreeBSD$"); 69 70 #include "opt_vm.h" 71 72 #include <sys/param.h> 73 #include <sys/systm.h> 74 #include <sys/cpuset.h> 75 #include <sys/lock.h> 76 #include <sys/mman.h> 77 #include <sys/mount.h> 78 #include <sys/kernel.h> 79 #include <sys/pctrie.h> 80 #include <sys/sysctl.h> 81 #include <sys/mutex.h> 82 #include <sys/proc.h> /* for curproc, pageproc */ 83 #include <sys/socket.h> 84 #include <sys/resourcevar.h> 85 #include <sys/rwlock.h> 86 #include <sys/user.h> 87 #include <sys/vnode.h> 88 #include <sys/vmmeter.h> 89 #include <sys/sx.h> 90 91 #include <vm/vm.h> 92 #include <vm/vm_param.h> 93 #include <vm/pmap.h> 94 #include <vm/vm_map.h> 95 #include <vm/vm_object.h> 96 #include <vm/vm_page.h> 97 #include <vm/vm_pageout.h> 98 #include <vm/vm_pager.h> 99 #include <vm/vm_phys.h> 100 #include <vm/vm_pagequeue.h> 101 #include <vm/swap_pager.h> 102 #include <vm/vm_kern.h> 103 #include <vm/vm_extern.h> 104 #include <vm/vm_radix.h> 105 #include <vm/vm_reserv.h> 106 #include <vm/uma.h> 107 108 static int old_msync; 109 SYSCTL_INT(_vm, OID_AUTO, old_msync, CTLFLAG_RW, &old_msync, 0, 110 "Use old (insecure) msync behavior"); 111 112 static int vm_object_page_collect_flush(vm_object_t object, vm_page_t p, 113 int pagerflags, int flags, boolean_t *clearobjflags, 114 boolean_t *eio); 115 static boolean_t vm_object_page_remove_write(vm_page_t p, int flags, 116 boolean_t *clearobjflags); 117 static void vm_object_qcollapse(vm_object_t object); 118 static void vm_object_vndeallocate(vm_object_t object); 119 120 /* 121 * Virtual memory objects maintain the actual data 122 * associated with allocated virtual memory. A given 123 * page of memory exists within exactly one object. 124 * 125 * An object is only deallocated when all "references" 126 * are given up. Only one "reference" to a given 127 * region of an object should be writeable. 128 * 129 * Associated with each object is a list of all resident 130 * memory pages belonging to that object; this list is 131 * maintained by the "vm_page" module, and locked by the object's 132 * lock. 133 * 134 * Each object also records a "pager" routine which is 135 * used to retrieve (and store) pages to the proper backing 136 * storage. In addition, objects may be backed by other 137 * objects from which they were virtual-copied. 138 * 139 * The only items within the object structure which are 140 * modified after time of creation are: 141 * reference count locked by object's lock 142 * pager routine locked by object's lock 143 * 144 */ 145 146 struct object_q vm_object_list; 147 struct mtx vm_object_list_mtx; /* lock for object list and count */ 148 149 struct vm_object kernel_object_store; 150 151 static SYSCTL_NODE(_vm_stats, OID_AUTO, object, CTLFLAG_RD, 0, 152 "VM object stats"); 153 154 static counter_u64_t object_collapses = EARLY_COUNTER; 155 SYSCTL_COUNTER_U64(_vm_stats_object, OID_AUTO, collapses, CTLFLAG_RD, 156 &object_collapses, 157 "VM object collapses"); 158 159 static counter_u64_t object_bypasses = EARLY_COUNTER; 160 SYSCTL_COUNTER_U64(_vm_stats_object, OID_AUTO, bypasses, CTLFLAG_RD, 161 &object_bypasses, 162 "VM object bypasses"); 163 164 static void 165 counter_startup(void) 166 { 167 168 object_collapses = counter_u64_alloc(M_WAITOK); 169 object_bypasses = counter_u64_alloc(M_WAITOK); 170 } 171 SYSINIT(object_counters, SI_SUB_CPU, SI_ORDER_ANY, counter_startup, NULL); 172 173 static uma_zone_t obj_zone; 174 175 static int vm_object_zinit(void *mem, int size, int flags); 176 177 #ifdef INVARIANTS 178 static void vm_object_zdtor(void *mem, int size, void *arg); 179 180 static void 181 vm_object_zdtor(void *mem, int size, void *arg) 182 { 183 vm_object_t object; 184 185 object = (vm_object_t)mem; 186 KASSERT(object->ref_count == 0, 187 ("object %p ref_count = %d", object, object->ref_count)); 188 KASSERT(TAILQ_EMPTY(&object->memq), 189 ("object %p has resident pages in its memq", object)); 190 KASSERT(vm_radix_is_empty(&object->rtree), 191 ("object %p has resident pages in its trie", object)); 192 #if VM_NRESERVLEVEL > 0 193 KASSERT(LIST_EMPTY(&object->rvq), 194 ("object %p has reservations", 195 object)); 196 #endif 197 KASSERT(object->paging_in_progress == 0, 198 ("object %p paging_in_progress = %d", 199 object, object->paging_in_progress)); 200 KASSERT(object->resident_page_count == 0, 201 ("object %p resident_page_count = %d", 202 object, object->resident_page_count)); 203 KASSERT(object->shadow_count == 0, 204 ("object %p shadow_count = %d", 205 object, object->shadow_count)); 206 KASSERT(object->type == OBJT_DEAD, 207 ("object %p has non-dead type %d", 208 object, object->type)); 209 } 210 #endif 211 212 static int 213 vm_object_zinit(void *mem, int size, int flags) 214 { 215 vm_object_t object; 216 217 object = (vm_object_t)mem; 218 rw_init_flags(&object->lock, "vm object", RW_DUPOK | RW_NEW); 219 220 /* These are true for any object that has been freed */ 221 object->type = OBJT_DEAD; 222 object->ref_count = 0; 223 vm_radix_init(&object->rtree); 224 object->paging_in_progress = 0; 225 object->resident_page_count = 0; 226 object->shadow_count = 0; 227 object->flags = OBJ_DEAD; 228 229 mtx_lock(&vm_object_list_mtx); 230 TAILQ_INSERT_TAIL(&vm_object_list, object, object_list); 231 mtx_unlock(&vm_object_list_mtx); 232 return (0); 233 } 234 235 static void 236 _vm_object_allocate(objtype_t type, vm_pindex_t size, vm_object_t object) 237 { 238 239 TAILQ_INIT(&object->memq); 240 LIST_INIT(&object->shadow_head); 241 242 object->type = type; 243 if (type == OBJT_SWAP) 244 pctrie_init(&object->un_pager.swp.swp_blks); 245 246 /* 247 * Ensure that swap_pager_swapoff() iteration over object_list 248 * sees up to date type and pctrie head if it observed 249 * non-dead object. 250 */ 251 atomic_thread_fence_rel(); 252 253 switch (type) { 254 case OBJT_DEAD: 255 panic("_vm_object_allocate: can't create OBJT_DEAD"); 256 case OBJT_DEFAULT: 257 case OBJT_SWAP: 258 object->flags = OBJ_ONEMAPPING; 259 break; 260 case OBJT_DEVICE: 261 case OBJT_SG: 262 object->flags = OBJ_FICTITIOUS | OBJ_UNMANAGED; 263 break; 264 case OBJT_MGTDEVICE: 265 object->flags = OBJ_FICTITIOUS; 266 break; 267 case OBJT_PHYS: 268 object->flags = OBJ_UNMANAGED; 269 break; 270 case OBJT_VNODE: 271 object->flags = 0; 272 break; 273 default: 274 panic("_vm_object_allocate: type %d is undefined", type); 275 } 276 object->size = size; 277 object->generation = 1; 278 object->ref_count = 1; 279 object->memattr = VM_MEMATTR_DEFAULT; 280 object->cred = NULL; 281 object->charge = 0; 282 object->handle = NULL; 283 object->backing_object = NULL; 284 object->backing_object_offset = (vm_ooffset_t) 0; 285 #if VM_NRESERVLEVEL > 0 286 LIST_INIT(&object->rvq); 287 #endif 288 umtx_shm_object_init(object); 289 } 290 291 /* 292 * vm_object_init: 293 * 294 * Initialize the VM objects module. 295 */ 296 void 297 vm_object_init(void) 298 { 299 TAILQ_INIT(&vm_object_list); 300 mtx_init(&vm_object_list_mtx, "vm object_list", NULL, MTX_DEF); 301 302 rw_init(&kernel_object->lock, "kernel vm object"); 303 _vm_object_allocate(OBJT_PHYS, atop(VM_MAX_KERNEL_ADDRESS - 304 VM_MIN_KERNEL_ADDRESS), kernel_object); 305 #if VM_NRESERVLEVEL > 0 306 kernel_object->flags |= OBJ_COLORED; 307 kernel_object->pg_color = (u_short)atop(VM_MIN_KERNEL_ADDRESS); 308 #endif 309 310 /* 311 * The lock portion of struct vm_object must be type stable due 312 * to vm_pageout_fallback_object_lock locking a vm object 313 * without holding any references to it. 314 */ 315 obj_zone = uma_zcreate("VM OBJECT", sizeof (struct vm_object), NULL, 316 #ifdef INVARIANTS 317 vm_object_zdtor, 318 #else 319 NULL, 320 #endif 321 vm_object_zinit, NULL, UMA_ALIGN_PTR, UMA_ZONE_NOFREE); 322 323 vm_radix_zinit(); 324 } 325 326 void 327 vm_object_clear_flag(vm_object_t object, u_short bits) 328 { 329 330 VM_OBJECT_ASSERT_WLOCKED(object); 331 object->flags &= ~bits; 332 } 333 334 /* 335 * Sets the default memory attribute for the specified object. Pages 336 * that are allocated to this object are by default assigned this memory 337 * attribute. 338 * 339 * Presently, this function must be called before any pages are allocated 340 * to the object. In the future, this requirement may be relaxed for 341 * "default" and "swap" objects. 342 */ 343 int 344 vm_object_set_memattr(vm_object_t object, vm_memattr_t memattr) 345 { 346 347 VM_OBJECT_ASSERT_WLOCKED(object); 348 switch (object->type) { 349 case OBJT_DEFAULT: 350 case OBJT_DEVICE: 351 case OBJT_MGTDEVICE: 352 case OBJT_PHYS: 353 case OBJT_SG: 354 case OBJT_SWAP: 355 case OBJT_VNODE: 356 if (!TAILQ_EMPTY(&object->memq)) 357 return (KERN_FAILURE); 358 break; 359 case OBJT_DEAD: 360 return (KERN_INVALID_ARGUMENT); 361 default: 362 panic("vm_object_set_memattr: object %p is of undefined type", 363 object); 364 } 365 object->memattr = memattr; 366 return (KERN_SUCCESS); 367 } 368 369 void 370 vm_object_pip_add(vm_object_t object, short i) 371 { 372 373 VM_OBJECT_ASSERT_WLOCKED(object); 374 object->paging_in_progress += i; 375 } 376 377 void 378 vm_object_pip_subtract(vm_object_t object, short i) 379 { 380 381 VM_OBJECT_ASSERT_WLOCKED(object); 382 object->paging_in_progress -= i; 383 } 384 385 void 386 vm_object_pip_wakeup(vm_object_t object) 387 { 388 389 VM_OBJECT_ASSERT_WLOCKED(object); 390 object->paging_in_progress--; 391 if ((object->flags & OBJ_PIPWNT) && object->paging_in_progress == 0) { 392 vm_object_clear_flag(object, OBJ_PIPWNT); 393 wakeup(object); 394 } 395 } 396 397 void 398 vm_object_pip_wakeupn(vm_object_t object, short i) 399 { 400 401 VM_OBJECT_ASSERT_WLOCKED(object); 402 if (i) 403 object->paging_in_progress -= i; 404 if ((object->flags & OBJ_PIPWNT) && object->paging_in_progress == 0) { 405 vm_object_clear_flag(object, OBJ_PIPWNT); 406 wakeup(object); 407 } 408 } 409 410 void 411 vm_object_pip_wait(vm_object_t object, char *waitid) 412 { 413 414 VM_OBJECT_ASSERT_WLOCKED(object); 415 while (object->paging_in_progress) { 416 object->flags |= OBJ_PIPWNT; 417 VM_OBJECT_SLEEP(object, object, PVM, waitid, 0); 418 } 419 } 420 421 /* 422 * vm_object_allocate: 423 * 424 * Returns a new object with the given size. 425 */ 426 vm_object_t 427 vm_object_allocate(objtype_t type, vm_pindex_t size) 428 { 429 vm_object_t object; 430 431 object = (vm_object_t)uma_zalloc(obj_zone, M_WAITOK); 432 _vm_object_allocate(type, size, object); 433 return (object); 434 } 435 436 437 /* 438 * vm_object_reference: 439 * 440 * Gets another reference to the given object. Note: OBJ_DEAD 441 * objects can be referenced during final cleaning. 442 */ 443 void 444 vm_object_reference(vm_object_t object) 445 { 446 if (object == NULL) 447 return; 448 VM_OBJECT_WLOCK(object); 449 vm_object_reference_locked(object); 450 VM_OBJECT_WUNLOCK(object); 451 } 452 453 /* 454 * vm_object_reference_locked: 455 * 456 * Gets another reference to the given object. 457 * 458 * The object must be locked. 459 */ 460 void 461 vm_object_reference_locked(vm_object_t object) 462 { 463 struct vnode *vp; 464 465 VM_OBJECT_ASSERT_WLOCKED(object); 466 object->ref_count++; 467 if (object->type == OBJT_VNODE) { 468 vp = object->handle; 469 vref(vp); 470 } 471 } 472 473 /* 474 * Handle deallocating an object of type OBJT_VNODE. 475 */ 476 static void 477 vm_object_vndeallocate(vm_object_t object) 478 { 479 struct vnode *vp = (struct vnode *) object->handle; 480 481 VM_OBJECT_ASSERT_WLOCKED(object); 482 KASSERT(object->type == OBJT_VNODE, 483 ("vm_object_vndeallocate: not a vnode object")); 484 KASSERT(vp != NULL, ("vm_object_vndeallocate: missing vp")); 485 #ifdef INVARIANTS 486 if (object->ref_count == 0) { 487 vn_printf(vp, "vm_object_vndeallocate "); 488 panic("vm_object_vndeallocate: bad object reference count"); 489 } 490 #endif 491 492 if (!umtx_shm_vnobj_persistent && object->ref_count == 1) 493 umtx_shm_object_terminated(object); 494 495 /* 496 * The test for text of vp vnode does not need a bypass to 497 * reach right VV_TEXT there, since it is obtained from 498 * object->handle. 499 */ 500 if (object->ref_count > 1 || (vp->v_vflag & VV_TEXT) == 0) { 501 object->ref_count--; 502 VM_OBJECT_WUNLOCK(object); 503 /* vrele may need the vnode lock. */ 504 vrele(vp); 505 } else { 506 vhold(vp); 507 VM_OBJECT_WUNLOCK(object); 508 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY); 509 vdrop(vp); 510 VM_OBJECT_WLOCK(object); 511 object->ref_count--; 512 if (object->type == OBJT_DEAD) { 513 VM_OBJECT_WUNLOCK(object); 514 VOP_UNLOCK(vp, 0); 515 } else { 516 if (object->ref_count == 0) 517 VOP_UNSET_TEXT(vp); 518 VM_OBJECT_WUNLOCK(object); 519 vput(vp); 520 } 521 } 522 } 523 524 /* 525 * vm_object_deallocate: 526 * 527 * Release a reference to the specified object, 528 * gained either through a vm_object_allocate 529 * or a vm_object_reference call. When all references 530 * are gone, storage associated with this object 531 * may be relinquished. 532 * 533 * No object may be locked. 534 */ 535 void 536 vm_object_deallocate(vm_object_t object) 537 { 538 vm_object_t temp; 539 struct vnode *vp; 540 541 while (object != NULL) { 542 VM_OBJECT_WLOCK(object); 543 if (object->type == OBJT_VNODE) { 544 vm_object_vndeallocate(object); 545 return; 546 } 547 548 KASSERT(object->ref_count != 0, 549 ("vm_object_deallocate: object deallocated too many times: %d", object->type)); 550 551 /* 552 * If the reference count goes to 0 we start calling 553 * vm_object_terminate() on the object chain. 554 * A ref count of 1 may be a special case depending on the 555 * shadow count being 0 or 1. 556 */ 557 object->ref_count--; 558 if (object->ref_count > 1) { 559 VM_OBJECT_WUNLOCK(object); 560 return; 561 } else if (object->ref_count == 1) { 562 if (object->type == OBJT_SWAP && 563 (object->flags & OBJ_TMPFS) != 0) { 564 vp = object->un_pager.swp.swp_tmpfs; 565 vhold(vp); 566 VM_OBJECT_WUNLOCK(object); 567 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY); 568 VM_OBJECT_WLOCK(object); 569 if (object->type == OBJT_DEAD || 570 object->ref_count != 1) { 571 VM_OBJECT_WUNLOCK(object); 572 VOP_UNLOCK(vp, 0); 573 vdrop(vp); 574 return; 575 } 576 if ((object->flags & OBJ_TMPFS) != 0) 577 VOP_UNSET_TEXT(vp); 578 VOP_UNLOCK(vp, 0); 579 vdrop(vp); 580 } 581 if (object->shadow_count == 0 && 582 object->handle == NULL && 583 (object->type == OBJT_DEFAULT || 584 (object->type == OBJT_SWAP && 585 (object->flags & OBJ_TMPFS_NODE) == 0))) { 586 vm_object_set_flag(object, OBJ_ONEMAPPING); 587 } else if ((object->shadow_count == 1) && 588 (object->handle == NULL) && 589 (object->type == OBJT_DEFAULT || 590 object->type == OBJT_SWAP)) { 591 vm_object_t robject; 592 593 robject = LIST_FIRST(&object->shadow_head); 594 KASSERT(robject != NULL, 595 ("vm_object_deallocate: ref_count: %d, shadow_count: %d", 596 object->ref_count, 597 object->shadow_count)); 598 KASSERT((robject->flags & OBJ_TMPFS_NODE) == 0, 599 ("shadowed tmpfs v_object %p", object)); 600 if (!VM_OBJECT_TRYWLOCK(robject)) { 601 /* 602 * Avoid a potential deadlock. 603 */ 604 object->ref_count++; 605 VM_OBJECT_WUNLOCK(object); 606 /* 607 * More likely than not the thread 608 * holding robject's lock has lower 609 * priority than the current thread. 610 * Let the lower priority thread run. 611 */ 612 pause("vmo_de", 1); 613 continue; 614 } 615 /* 616 * Collapse object into its shadow unless its 617 * shadow is dead. In that case, object will 618 * be deallocated by the thread that is 619 * deallocating its shadow. 620 */ 621 if ((robject->flags & OBJ_DEAD) == 0 && 622 (robject->handle == NULL) && 623 (robject->type == OBJT_DEFAULT || 624 robject->type == OBJT_SWAP)) { 625 626 robject->ref_count++; 627 retry: 628 if (robject->paging_in_progress) { 629 VM_OBJECT_WUNLOCK(object); 630 vm_object_pip_wait(robject, 631 "objde1"); 632 temp = robject->backing_object; 633 if (object == temp) { 634 VM_OBJECT_WLOCK(object); 635 goto retry; 636 } 637 } else if (object->paging_in_progress) { 638 VM_OBJECT_WUNLOCK(robject); 639 object->flags |= OBJ_PIPWNT; 640 VM_OBJECT_SLEEP(object, object, 641 PDROP | PVM, "objde2", 0); 642 VM_OBJECT_WLOCK(robject); 643 temp = robject->backing_object; 644 if (object == temp) { 645 VM_OBJECT_WLOCK(object); 646 goto retry; 647 } 648 } else 649 VM_OBJECT_WUNLOCK(object); 650 651 if (robject->ref_count == 1) { 652 robject->ref_count--; 653 object = robject; 654 goto doterm; 655 } 656 object = robject; 657 vm_object_collapse(object); 658 VM_OBJECT_WUNLOCK(object); 659 continue; 660 } 661 VM_OBJECT_WUNLOCK(robject); 662 } 663 VM_OBJECT_WUNLOCK(object); 664 return; 665 } 666 doterm: 667 umtx_shm_object_terminated(object); 668 temp = object->backing_object; 669 if (temp != NULL) { 670 KASSERT((object->flags & OBJ_TMPFS_NODE) == 0, 671 ("shadowed tmpfs v_object 2 %p", object)); 672 VM_OBJECT_WLOCK(temp); 673 LIST_REMOVE(object, shadow_list); 674 temp->shadow_count--; 675 VM_OBJECT_WUNLOCK(temp); 676 object->backing_object = NULL; 677 } 678 /* 679 * Don't double-terminate, we could be in a termination 680 * recursion due to the terminate having to sync data 681 * to disk. 682 */ 683 if ((object->flags & OBJ_DEAD) == 0) 684 vm_object_terminate(object); 685 else 686 VM_OBJECT_WUNLOCK(object); 687 object = temp; 688 } 689 } 690 691 /* 692 * vm_object_destroy removes the object from the global object list 693 * and frees the space for the object. 694 */ 695 void 696 vm_object_destroy(vm_object_t object) 697 { 698 699 /* 700 * Release the allocation charge. 701 */ 702 if (object->cred != NULL) { 703 swap_release_by_cred(object->charge, object->cred); 704 object->charge = 0; 705 crfree(object->cred); 706 object->cred = NULL; 707 } 708 709 /* 710 * Free the space for the object. 711 */ 712 uma_zfree(obj_zone, object); 713 } 714 715 /* 716 * vm_object_terminate_pages removes any remaining pageable pages 717 * from the object and resets the object to an empty state. 718 */ 719 static void 720 vm_object_terminate_pages(vm_object_t object) 721 { 722 vm_page_t p, p_next; 723 struct mtx *mtx, *mtx1; 724 struct vm_pagequeue *pq, *pq1; 725 int dequeued; 726 727 VM_OBJECT_ASSERT_WLOCKED(object); 728 729 mtx = NULL; 730 pq = NULL; 731 732 /* 733 * Free any remaining pageable pages. This also removes them from the 734 * paging queues. However, don't free wired pages, just remove them 735 * from the object. Rather than incrementally removing each page from 736 * the object, the page and object are reset to any empty state. 737 */ 738 TAILQ_FOREACH_SAFE(p, &object->memq, listq, p_next) { 739 vm_page_assert_unbusied(p); 740 if ((object->flags & OBJ_UNMANAGED) == 0) { 741 /* 742 * vm_page_free_prep() only needs the page 743 * lock for managed pages. 744 */ 745 mtx1 = vm_page_lockptr(p); 746 if (mtx1 != mtx) { 747 if (mtx != NULL) 748 mtx_unlock(mtx); 749 if (pq != NULL) { 750 vm_pagequeue_cnt_add(pq, dequeued); 751 vm_pagequeue_unlock(pq); 752 pq = NULL; 753 } 754 mtx = mtx1; 755 mtx_lock(mtx); 756 } 757 } 758 p->object = NULL; 759 if (p->wire_count != 0) 760 goto unlist; 761 VM_CNT_INC(v_pfree); 762 p->flags &= ~PG_ZERO; 763 if (p->queue != PQ_NONE) { 764 KASSERT(p->queue < PQ_COUNT, ("vm_object_terminate: " 765 "page %p is not queued", p)); 766 pq1 = vm_page_pagequeue(p); 767 if (pq != pq1) { 768 if (pq != NULL) { 769 vm_pagequeue_cnt_add(pq, dequeued); 770 vm_pagequeue_unlock(pq); 771 } 772 pq = pq1; 773 vm_pagequeue_lock(pq); 774 dequeued = 0; 775 } 776 p->queue = PQ_NONE; 777 TAILQ_REMOVE(&pq->pq_pl, p, plinks.q); 778 dequeued--; 779 } 780 if (vm_page_free_prep(p, true)) 781 continue; 782 unlist: 783 TAILQ_REMOVE(&object->memq, p, listq); 784 } 785 if (pq != NULL) { 786 vm_pagequeue_cnt_add(pq, dequeued); 787 vm_pagequeue_unlock(pq); 788 } 789 if (mtx != NULL) 790 mtx_unlock(mtx); 791 792 vm_page_free_phys_pglist(&object->memq); 793 794 /* 795 * If the object contained any pages, then reset it to an empty state. 796 * None of the object's fields, including "resident_page_count", were 797 * modified by the preceding loop. 798 */ 799 if (object->resident_page_count != 0) { 800 vm_radix_reclaim_allnodes(&object->rtree); 801 TAILQ_INIT(&object->memq); 802 object->resident_page_count = 0; 803 if (object->type == OBJT_VNODE) 804 vdrop(object->handle); 805 } 806 } 807 808 /* 809 * vm_object_terminate actually destroys the specified object, freeing 810 * up all previously used resources. 811 * 812 * The object must be locked. 813 * This routine may block. 814 */ 815 void 816 vm_object_terminate(vm_object_t object) 817 { 818 819 VM_OBJECT_ASSERT_WLOCKED(object); 820 821 /* 822 * Make sure no one uses us. 823 */ 824 vm_object_set_flag(object, OBJ_DEAD); 825 826 /* 827 * wait for the pageout daemon to be done with the object 828 */ 829 vm_object_pip_wait(object, "objtrm"); 830 831 KASSERT(!object->paging_in_progress, 832 ("vm_object_terminate: pageout in progress")); 833 834 /* 835 * Clean and free the pages, as appropriate. All references to the 836 * object are gone, so we don't need to lock it. 837 */ 838 if (object->type == OBJT_VNODE) { 839 struct vnode *vp = (struct vnode *)object->handle; 840 841 /* 842 * Clean pages and flush buffers. 843 */ 844 vm_object_page_clean(object, 0, 0, OBJPC_SYNC); 845 VM_OBJECT_WUNLOCK(object); 846 847 vinvalbuf(vp, V_SAVE, 0, 0); 848 849 BO_LOCK(&vp->v_bufobj); 850 vp->v_bufobj.bo_flag |= BO_DEAD; 851 BO_UNLOCK(&vp->v_bufobj); 852 853 VM_OBJECT_WLOCK(object); 854 } 855 856 KASSERT(object->ref_count == 0, 857 ("vm_object_terminate: object with references, ref_count=%d", 858 object->ref_count)); 859 860 if ((object->flags & OBJ_PG_DTOR) == 0) 861 vm_object_terminate_pages(object); 862 863 #if VM_NRESERVLEVEL > 0 864 if (__predict_false(!LIST_EMPTY(&object->rvq))) 865 vm_reserv_break_all(object); 866 #endif 867 868 KASSERT(object->cred == NULL || object->type == OBJT_DEFAULT || 869 object->type == OBJT_SWAP, 870 ("%s: non-swap obj %p has cred", __func__, object)); 871 872 /* 873 * Let the pager know object is dead. 874 */ 875 vm_pager_deallocate(object); 876 VM_OBJECT_WUNLOCK(object); 877 878 vm_object_destroy(object); 879 } 880 881 /* 882 * Make the page read-only so that we can clear the object flags. However, if 883 * this is a nosync mmap then the object is likely to stay dirty so do not 884 * mess with the page and do not clear the object flags. Returns TRUE if the 885 * page should be flushed, and FALSE otherwise. 886 */ 887 static boolean_t 888 vm_object_page_remove_write(vm_page_t p, int flags, boolean_t *clearobjflags) 889 { 890 891 /* 892 * If we have been asked to skip nosync pages and this is a 893 * nosync page, skip it. Note that the object flags were not 894 * cleared in this case so we do not have to set them. 895 */ 896 if ((flags & OBJPC_NOSYNC) != 0 && (p->oflags & VPO_NOSYNC) != 0) { 897 *clearobjflags = FALSE; 898 return (FALSE); 899 } else { 900 pmap_remove_write(p); 901 return (p->dirty != 0); 902 } 903 } 904 905 /* 906 * vm_object_page_clean 907 * 908 * Clean all dirty pages in the specified range of object. Leaves page 909 * on whatever queue it is currently on. If NOSYNC is set then do not 910 * write out pages with VPO_NOSYNC set (originally comes from MAP_NOSYNC), 911 * leaving the object dirty. 912 * 913 * When stuffing pages asynchronously, allow clustering. XXX we need a 914 * synchronous clustering mode implementation. 915 * 916 * Odd semantics: if start == end, we clean everything. 917 * 918 * The object must be locked. 919 * 920 * Returns FALSE if some page from the range was not written, as 921 * reported by the pager, and TRUE otherwise. 922 */ 923 boolean_t 924 vm_object_page_clean(vm_object_t object, vm_ooffset_t start, vm_ooffset_t end, 925 int flags) 926 { 927 vm_page_t np, p; 928 vm_pindex_t pi, tend, tstart; 929 int curgeneration, n, pagerflags; 930 boolean_t clearobjflags, eio, res; 931 932 VM_OBJECT_ASSERT_WLOCKED(object); 933 934 /* 935 * The OBJ_MIGHTBEDIRTY flag is only set for OBJT_VNODE 936 * objects. The check below prevents the function from 937 * operating on non-vnode objects. 938 */ 939 if ((object->flags & OBJ_MIGHTBEDIRTY) == 0 || 940 object->resident_page_count == 0) 941 return (TRUE); 942 943 pagerflags = (flags & (OBJPC_SYNC | OBJPC_INVAL)) != 0 ? 944 VM_PAGER_PUT_SYNC : VM_PAGER_CLUSTER_OK; 945 pagerflags |= (flags & OBJPC_INVAL) != 0 ? VM_PAGER_PUT_INVAL : 0; 946 947 tstart = OFF_TO_IDX(start); 948 tend = (end == 0) ? object->size : OFF_TO_IDX(end + PAGE_MASK); 949 clearobjflags = tstart == 0 && tend >= object->size; 950 res = TRUE; 951 952 rescan: 953 curgeneration = object->generation; 954 955 for (p = vm_page_find_least(object, tstart); p != NULL; p = np) { 956 pi = p->pindex; 957 if (pi >= tend) 958 break; 959 np = TAILQ_NEXT(p, listq); 960 if (p->valid == 0) 961 continue; 962 if (vm_page_sleep_if_busy(p, "vpcwai")) { 963 if (object->generation != curgeneration) { 964 if ((flags & OBJPC_SYNC) != 0) 965 goto rescan; 966 else 967 clearobjflags = FALSE; 968 } 969 np = vm_page_find_least(object, pi); 970 continue; 971 } 972 if (!vm_object_page_remove_write(p, flags, &clearobjflags)) 973 continue; 974 975 n = vm_object_page_collect_flush(object, p, pagerflags, 976 flags, &clearobjflags, &eio); 977 if (eio) { 978 res = FALSE; 979 clearobjflags = FALSE; 980 } 981 if (object->generation != curgeneration) { 982 if ((flags & OBJPC_SYNC) != 0) 983 goto rescan; 984 else 985 clearobjflags = FALSE; 986 } 987 988 /* 989 * If the VOP_PUTPAGES() did a truncated write, so 990 * that even the first page of the run is not fully 991 * written, vm_pageout_flush() returns 0 as the run 992 * length. Since the condition that caused truncated 993 * write may be permanent, e.g. exhausted free space, 994 * accepting n == 0 would cause an infinite loop. 995 * 996 * Forwarding the iterator leaves the unwritten page 997 * behind, but there is not much we can do there if 998 * filesystem refuses to write it. 999 */ 1000 if (n == 0) { 1001 n = 1; 1002 clearobjflags = FALSE; 1003 } 1004 np = vm_page_find_least(object, pi + n); 1005 } 1006 #if 0 1007 VOP_FSYNC(vp, (pagerflags & VM_PAGER_PUT_SYNC) ? MNT_WAIT : 0); 1008 #endif 1009 1010 if (clearobjflags) 1011 vm_object_clear_flag(object, OBJ_MIGHTBEDIRTY); 1012 return (res); 1013 } 1014 1015 static int 1016 vm_object_page_collect_flush(vm_object_t object, vm_page_t p, int pagerflags, 1017 int flags, boolean_t *clearobjflags, boolean_t *eio) 1018 { 1019 vm_page_t ma[vm_pageout_page_count], p_first, tp; 1020 int count, i, mreq, runlen; 1021 1022 vm_page_lock_assert(p, MA_NOTOWNED); 1023 VM_OBJECT_ASSERT_WLOCKED(object); 1024 1025 count = 1; 1026 mreq = 0; 1027 1028 for (tp = p; count < vm_pageout_page_count; count++) { 1029 tp = vm_page_next(tp); 1030 if (tp == NULL || vm_page_busied(tp)) 1031 break; 1032 if (!vm_object_page_remove_write(tp, flags, clearobjflags)) 1033 break; 1034 } 1035 1036 for (p_first = p; count < vm_pageout_page_count; count++) { 1037 tp = vm_page_prev(p_first); 1038 if (tp == NULL || vm_page_busied(tp)) 1039 break; 1040 if (!vm_object_page_remove_write(tp, flags, clearobjflags)) 1041 break; 1042 p_first = tp; 1043 mreq++; 1044 } 1045 1046 for (tp = p_first, i = 0; i < count; tp = TAILQ_NEXT(tp, listq), i++) 1047 ma[i] = tp; 1048 1049 vm_pageout_flush(ma, count, pagerflags, mreq, &runlen, eio); 1050 return (runlen); 1051 } 1052 1053 /* 1054 * Note that there is absolutely no sense in writing out 1055 * anonymous objects, so we track down the vnode object 1056 * to write out. 1057 * We invalidate (remove) all pages from the address space 1058 * for semantic correctness. 1059 * 1060 * If the backing object is a device object with unmanaged pages, then any 1061 * mappings to the specified range of pages must be removed before this 1062 * function is called. 1063 * 1064 * Note: certain anonymous maps, such as MAP_NOSYNC maps, 1065 * may start out with a NULL object. 1066 */ 1067 boolean_t 1068 vm_object_sync(vm_object_t object, vm_ooffset_t offset, vm_size_t size, 1069 boolean_t syncio, boolean_t invalidate) 1070 { 1071 vm_object_t backing_object; 1072 struct vnode *vp; 1073 struct mount *mp; 1074 int error, flags, fsync_after; 1075 boolean_t res; 1076 1077 if (object == NULL) 1078 return (TRUE); 1079 res = TRUE; 1080 error = 0; 1081 VM_OBJECT_WLOCK(object); 1082 while ((backing_object = object->backing_object) != NULL) { 1083 VM_OBJECT_WLOCK(backing_object); 1084 offset += object->backing_object_offset; 1085 VM_OBJECT_WUNLOCK(object); 1086 object = backing_object; 1087 if (object->size < OFF_TO_IDX(offset + size)) 1088 size = IDX_TO_OFF(object->size) - offset; 1089 } 1090 /* 1091 * Flush pages if writing is allowed, invalidate them 1092 * if invalidation requested. Pages undergoing I/O 1093 * will be ignored by vm_object_page_remove(). 1094 * 1095 * We cannot lock the vnode and then wait for paging 1096 * to complete without deadlocking against vm_fault. 1097 * Instead we simply call vm_object_page_remove() and 1098 * allow it to block internally on a page-by-page 1099 * basis when it encounters pages undergoing async 1100 * I/O. 1101 */ 1102 if (object->type == OBJT_VNODE && 1103 (object->flags & OBJ_MIGHTBEDIRTY) != 0 && 1104 ((vp = object->handle)->v_vflag & VV_NOSYNC) == 0) { 1105 VM_OBJECT_WUNLOCK(object); 1106 (void) vn_start_write(vp, &mp, V_WAIT); 1107 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY); 1108 if (syncio && !invalidate && offset == 0 && 1109 atop(size) == object->size) { 1110 /* 1111 * If syncing the whole mapping of the file, 1112 * it is faster to schedule all the writes in 1113 * async mode, also allowing the clustering, 1114 * and then wait for i/o to complete. 1115 */ 1116 flags = 0; 1117 fsync_after = TRUE; 1118 } else { 1119 flags = (syncio || invalidate) ? OBJPC_SYNC : 0; 1120 flags |= invalidate ? (OBJPC_SYNC | OBJPC_INVAL) : 0; 1121 fsync_after = FALSE; 1122 } 1123 VM_OBJECT_WLOCK(object); 1124 res = vm_object_page_clean(object, offset, offset + size, 1125 flags); 1126 VM_OBJECT_WUNLOCK(object); 1127 if (fsync_after) 1128 error = VOP_FSYNC(vp, MNT_WAIT, curthread); 1129 VOP_UNLOCK(vp, 0); 1130 vn_finished_write(mp); 1131 if (error != 0) 1132 res = FALSE; 1133 VM_OBJECT_WLOCK(object); 1134 } 1135 if ((object->type == OBJT_VNODE || 1136 object->type == OBJT_DEVICE) && invalidate) { 1137 if (object->type == OBJT_DEVICE) 1138 /* 1139 * The option OBJPR_NOTMAPPED must be passed here 1140 * because vm_object_page_remove() cannot remove 1141 * unmanaged mappings. 1142 */ 1143 flags = OBJPR_NOTMAPPED; 1144 else if (old_msync) 1145 flags = 0; 1146 else 1147 flags = OBJPR_CLEANONLY; 1148 vm_object_page_remove(object, OFF_TO_IDX(offset), 1149 OFF_TO_IDX(offset + size + PAGE_MASK), flags); 1150 } 1151 VM_OBJECT_WUNLOCK(object); 1152 return (res); 1153 } 1154 1155 /* 1156 * Determine whether the given advice can be applied to the object. Advice is 1157 * not applied to unmanaged pages since they never belong to page queues, and 1158 * since MADV_FREE is destructive, it can apply only to anonymous pages that 1159 * have been mapped at most once. 1160 */ 1161 static bool 1162 vm_object_advice_applies(vm_object_t object, int advice) 1163 { 1164 1165 if ((object->flags & OBJ_UNMANAGED) != 0) 1166 return (false); 1167 if (advice != MADV_FREE) 1168 return (true); 1169 return ((object->type == OBJT_DEFAULT || object->type == OBJT_SWAP) && 1170 (object->flags & OBJ_ONEMAPPING) != 0); 1171 } 1172 1173 static void 1174 vm_object_madvise_freespace(vm_object_t object, int advice, vm_pindex_t pindex, 1175 vm_size_t size) 1176 { 1177 1178 if (advice == MADV_FREE && object->type == OBJT_SWAP) 1179 swap_pager_freespace(object, pindex, size); 1180 } 1181 1182 /* 1183 * vm_object_madvise: 1184 * 1185 * Implements the madvise function at the object/page level. 1186 * 1187 * MADV_WILLNEED (any object) 1188 * 1189 * Activate the specified pages if they are resident. 1190 * 1191 * MADV_DONTNEED (any object) 1192 * 1193 * Deactivate the specified pages if they are resident. 1194 * 1195 * MADV_FREE (OBJT_DEFAULT/OBJT_SWAP objects, 1196 * OBJ_ONEMAPPING only) 1197 * 1198 * Deactivate and clean the specified pages if they are 1199 * resident. This permits the process to reuse the pages 1200 * without faulting or the kernel to reclaim the pages 1201 * without I/O. 1202 */ 1203 void 1204 vm_object_madvise(vm_object_t object, vm_pindex_t pindex, vm_pindex_t end, 1205 int advice) 1206 { 1207 vm_pindex_t tpindex; 1208 vm_object_t backing_object, tobject; 1209 vm_page_t m, tm; 1210 1211 if (object == NULL) 1212 return; 1213 1214 relookup: 1215 VM_OBJECT_WLOCK(object); 1216 if (!vm_object_advice_applies(object, advice)) { 1217 VM_OBJECT_WUNLOCK(object); 1218 return; 1219 } 1220 for (m = vm_page_find_least(object, pindex); pindex < end; pindex++) { 1221 tobject = object; 1222 1223 /* 1224 * If the next page isn't resident in the top-level object, we 1225 * need to search the shadow chain. When applying MADV_FREE, we 1226 * take care to release any swap space used to store 1227 * non-resident pages. 1228 */ 1229 if (m == NULL || pindex < m->pindex) { 1230 /* 1231 * Optimize a common case: if the top-level object has 1232 * no backing object, we can skip over the non-resident 1233 * range in constant time. 1234 */ 1235 if (object->backing_object == NULL) { 1236 tpindex = (m != NULL && m->pindex < end) ? 1237 m->pindex : end; 1238 vm_object_madvise_freespace(object, advice, 1239 pindex, tpindex - pindex); 1240 if ((pindex = tpindex) == end) 1241 break; 1242 goto next_page; 1243 } 1244 1245 tpindex = pindex; 1246 do { 1247 vm_object_madvise_freespace(tobject, advice, 1248 tpindex, 1); 1249 /* 1250 * Prepare to search the next object in the 1251 * chain. 1252 */ 1253 backing_object = tobject->backing_object; 1254 if (backing_object == NULL) 1255 goto next_pindex; 1256 VM_OBJECT_WLOCK(backing_object); 1257 tpindex += 1258 OFF_TO_IDX(tobject->backing_object_offset); 1259 if (tobject != object) 1260 VM_OBJECT_WUNLOCK(tobject); 1261 tobject = backing_object; 1262 if (!vm_object_advice_applies(tobject, advice)) 1263 goto next_pindex; 1264 } while ((tm = vm_page_lookup(tobject, tpindex)) == 1265 NULL); 1266 } else { 1267 next_page: 1268 tm = m; 1269 m = TAILQ_NEXT(m, listq); 1270 } 1271 1272 /* 1273 * If the page is not in a normal state, skip it. 1274 */ 1275 if (tm->valid != VM_PAGE_BITS_ALL) 1276 goto next_pindex; 1277 vm_page_lock(tm); 1278 if (vm_page_held(tm)) { 1279 vm_page_unlock(tm); 1280 goto next_pindex; 1281 } 1282 KASSERT((tm->flags & PG_FICTITIOUS) == 0, 1283 ("vm_object_madvise: page %p is fictitious", tm)); 1284 KASSERT((tm->oflags & VPO_UNMANAGED) == 0, 1285 ("vm_object_madvise: page %p is not managed", tm)); 1286 if (vm_page_busied(tm)) { 1287 if (object != tobject) 1288 VM_OBJECT_WUNLOCK(tobject); 1289 VM_OBJECT_WUNLOCK(object); 1290 if (advice == MADV_WILLNEED) { 1291 /* 1292 * Reference the page before unlocking and 1293 * sleeping so that the page daemon is less 1294 * likely to reclaim it. 1295 */ 1296 vm_page_aflag_set(tm, PGA_REFERENCED); 1297 } 1298 vm_page_busy_sleep(tm, "madvpo", false); 1299 goto relookup; 1300 } 1301 vm_page_advise(tm, advice); 1302 vm_page_unlock(tm); 1303 vm_object_madvise_freespace(tobject, advice, tm->pindex, 1); 1304 next_pindex: 1305 if (tobject != object) 1306 VM_OBJECT_WUNLOCK(tobject); 1307 } 1308 VM_OBJECT_WUNLOCK(object); 1309 } 1310 1311 /* 1312 * vm_object_shadow: 1313 * 1314 * Create a new object which is backed by the 1315 * specified existing object range. The source 1316 * object reference is deallocated. 1317 * 1318 * The new object and offset into that object 1319 * are returned in the source parameters. 1320 */ 1321 void 1322 vm_object_shadow( 1323 vm_object_t *object, /* IN/OUT */ 1324 vm_ooffset_t *offset, /* IN/OUT */ 1325 vm_size_t length) 1326 { 1327 vm_object_t source; 1328 vm_object_t result; 1329 1330 source = *object; 1331 1332 /* 1333 * Don't create the new object if the old object isn't shared. 1334 */ 1335 if (source != NULL) { 1336 VM_OBJECT_WLOCK(source); 1337 if (source->ref_count == 1 && 1338 source->handle == NULL && 1339 (source->type == OBJT_DEFAULT || 1340 source->type == OBJT_SWAP)) { 1341 VM_OBJECT_WUNLOCK(source); 1342 return; 1343 } 1344 VM_OBJECT_WUNLOCK(source); 1345 } 1346 1347 /* 1348 * Allocate a new object with the given length. 1349 */ 1350 result = vm_object_allocate(OBJT_DEFAULT, atop(length)); 1351 1352 /* 1353 * The new object shadows the source object, adding a reference to it. 1354 * Our caller changes his reference to point to the new object, 1355 * removing a reference to the source object. Net result: no change 1356 * of reference count. 1357 * 1358 * Try to optimize the result object's page color when shadowing 1359 * in order to maintain page coloring consistency in the combined 1360 * shadowed object. 1361 */ 1362 result->backing_object = source; 1363 /* 1364 * Store the offset into the source object, and fix up the offset into 1365 * the new object. 1366 */ 1367 result->backing_object_offset = *offset; 1368 if (source != NULL) { 1369 VM_OBJECT_WLOCK(source); 1370 result->domain = source->domain; 1371 LIST_INSERT_HEAD(&source->shadow_head, result, shadow_list); 1372 source->shadow_count++; 1373 #if VM_NRESERVLEVEL > 0 1374 result->flags |= source->flags & OBJ_COLORED; 1375 result->pg_color = (source->pg_color + OFF_TO_IDX(*offset)) & 1376 ((1 << (VM_NFREEORDER - 1)) - 1); 1377 #endif 1378 VM_OBJECT_WUNLOCK(source); 1379 } 1380 1381 1382 /* 1383 * Return the new things 1384 */ 1385 *offset = 0; 1386 *object = result; 1387 } 1388 1389 /* 1390 * vm_object_split: 1391 * 1392 * Split the pages in a map entry into a new object. This affords 1393 * easier removal of unused pages, and keeps object inheritance from 1394 * being a negative impact on memory usage. 1395 */ 1396 void 1397 vm_object_split(vm_map_entry_t entry) 1398 { 1399 vm_page_t m, m_next; 1400 vm_object_t orig_object, new_object, source; 1401 vm_pindex_t idx, offidxstart; 1402 vm_size_t size; 1403 1404 orig_object = entry->object.vm_object; 1405 if (orig_object->type != OBJT_DEFAULT && orig_object->type != OBJT_SWAP) 1406 return; 1407 if (orig_object->ref_count <= 1) 1408 return; 1409 VM_OBJECT_WUNLOCK(orig_object); 1410 1411 offidxstart = OFF_TO_IDX(entry->offset); 1412 size = atop(entry->end - entry->start); 1413 1414 /* 1415 * If swap_pager_copy() is later called, it will convert new_object 1416 * into a swap object. 1417 */ 1418 new_object = vm_object_allocate(OBJT_DEFAULT, size); 1419 1420 /* 1421 * At this point, the new object is still private, so the order in 1422 * which the original and new objects are locked does not matter. 1423 */ 1424 VM_OBJECT_WLOCK(new_object); 1425 VM_OBJECT_WLOCK(orig_object); 1426 new_object->domain = orig_object->domain; 1427 source = orig_object->backing_object; 1428 if (source != NULL) { 1429 VM_OBJECT_WLOCK(source); 1430 if ((source->flags & OBJ_DEAD) != 0) { 1431 VM_OBJECT_WUNLOCK(source); 1432 VM_OBJECT_WUNLOCK(orig_object); 1433 VM_OBJECT_WUNLOCK(new_object); 1434 vm_object_deallocate(new_object); 1435 VM_OBJECT_WLOCK(orig_object); 1436 return; 1437 } 1438 LIST_INSERT_HEAD(&source->shadow_head, 1439 new_object, shadow_list); 1440 source->shadow_count++; 1441 vm_object_reference_locked(source); /* for new_object */ 1442 vm_object_clear_flag(source, OBJ_ONEMAPPING); 1443 VM_OBJECT_WUNLOCK(source); 1444 new_object->backing_object_offset = 1445 orig_object->backing_object_offset + entry->offset; 1446 new_object->backing_object = source; 1447 } 1448 if (orig_object->cred != NULL) { 1449 new_object->cred = orig_object->cred; 1450 crhold(orig_object->cred); 1451 new_object->charge = ptoa(size); 1452 KASSERT(orig_object->charge >= ptoa(size), 1453 ("orig_object->charge < 0")); 1454 orig_object->charge -= ptoa(size); 1455 } 1456 retry: 1457 m = vm_page_find_least(orig_object, offidxstart); 1458 for (; m != NULL && (idx = m->pindex - offidxstart) < size; 1459 m = m_next) { 1460 m_next = TAILQ_NEXT(m, listq); 1461 1462 /* 1463 * We must wait for pending I/O to complete before we can 1464 * rename the page. 1465 * 1466 * We do not have to VM_PROT_NONE the page as mappings should 1467 * not be changed by this operation. 1468 */ 1469 if (vm_page_busied(m)) { 1470 VM_OBJECT_WUNLOCK(new_object); 1471 vm_page_lock(m); 1472 VM_OBJECT_WUNLOCK(orig_object); 1473 vm_page_busy_sleep(m, "spltwt", false); 1474 VM_OBJECT_WLOCK(orig_object); 1475 VM_OBJECT_WLOCK(new_object); 1476 goto retry; 1477 } 1478 1479 /* vm_page_rename() will dirty the page. */ 1480 if (vm_page_rename(m, new_object, idx)) { 1481 VM_OBJECT_WUNLOCK(new_object); 1482 VM_OBJECT_WUNLOCK(orig_object); 1483 vm_radix_wait(); 1484 VM_OBJECT_WLOCK(orig_object); 1485 VM_OBJECT_WLOCK(new_object); 1486 goto retry; 1487 } 1488 #if VM_NRESERVLEVEL > 0 1489 /* 1490 * If some of the reservation's allocated pages remain with 1491 * the original object, then transferring the reservation to 1492 * the new object is neither particularly beneficial nor 1493 * particularly harmful as compared to leaving the reservation 1494 * with the original object. If, however, all of the 1495 * reservation's allocated pages are transferred to the new 1496 * object, then transferring the reservation is typically 1497 * beneficial. Determining which of these two cases applies 1498 * would be more costly than unconditionally renaming the 1499 * reservation. 1500 */ 1501 vm_reserv_rename(m, new_object, orig_object, offidxstart); 1502 #endif 1503 if (orig_object->type == OBJT_SWAP) 1504 vm_page_xbusy(m); 1505 } 1506 if (orig_object->type == OBJT_SWAP) { 1507 /* 1508 * swap_pager_copy() can sleep, in which case the orig_object's 1509 * and new_object's locks are released and reacquired. 1510 */ 1511 swap_pager_copy(orig_object, new_object, offidxstart, 0); 1512 TAILQ_FOREACH(m, &new_object->memq, listq) 1513 vm_page_xunbusy(m); 1514 } 1515 VM_OBJECT_WUNLOCK(orig_object); 1516 VM_OBJECT_WUNLOCK(new_object); 1517 entry->object.vm_object = new_object; 1518 entry->offset = 0LL; 1519 vm_object_deallocate(orig_object); 1520 VM_OBJECT_WLOCK(new_object); 1521 } 1522 1523 #define OBSC_COLLAPSE_NOWAIT 0x0002 1524 #define OBSC_COLLAPSE_WAIT 0x0004 1525 1526 static vm_page_t 1527 vm_object_collapse_scan_wait(vm_object_t object, vm_page_t p, vm_page_t next, 1528 int op) 1529 { 1530 vm_object_t backing_object; 1531 1532 VM_OBJECT_ASSERT_WLOCKED(object); 1533 backing_object = object->backing_object; 1534 VM_OBJECT_ASSERT_WLOCKED(backing_object); 1535 1536 KASSERT(p == NULL || vm_page_busied(p), ("unbusy page %p", p)); 1537 KASSERT(p == NULL || p->object == object || p->object == backing_object, 1538 ("invalid ownership %p %p %p", p, object, backing_object)); 1539 if ((op & OBSC_COLLAPSE_NOWAIT) != 0) 1540 return (next); 1541 if (p != NULL) 1542 vm_page_lock(p); 1543 VM_OBJECT_WUNLOCK(object); 1544 VM_OBJECT_WUNLOCK(backing_object); 1545 /* The page is only NULL when rename fails. */ 1546 if (p == NULL) 1547 vm_radix_wait(); 1548 else 1549 vm_page_busy_sleep(p, "vmocol", false); 1550 VM_OBJECT_WLOCK(object); 1551 VM_OBJECT_WLOCK(backing_object); 1552 return (TAILQ_FIRST(&backing_object->memq)); 1553 } 1554 1555 static bool 1556 vm_object_scan_all_shadowed(vm_object_t object) 1557 { 1558 vm_object_t backing_object; 1559 vm_page_t p, pp; 1560 vm_pindex_t backing_offset_index, new_pindex, pi, ps; 1561 1562 VM_OBJECT_ASSERT_WLOCKED(object); 1563 VM_OBJECT_ASSERT_WLOCKED(object->backing_object); 1564 1565 backing_object = object->backing_object; 1566 1567 if (backing_object->type != OBJT_DEFAULT && 1568 backing_object->type != OBJT_SWAP) 1569 return (false); 1570 1571 pi = backing_offset_index = OFF_TO_IDX(object->backing_object_offset); 1572 p = vm_page_find_least(backing_object, pi); 1573 ps = swap_pager_find_least(backing_object, pi); 1574 1575 /* 1576 * Only check pages inside the parent object's range and 1577 * inside the parent object's mapping of the backing object. 1578 */ 1579 for (;; pi++) { 1580 if (p != NULL && p->pindex < pi) 1581 p = TAILQ_NEXT(p, listq); 1582 if (ps < pi) 1583 ps = swap_pager_find_least(backing_object, pi); 1584 if (p == NULL && ps >= backing_object->size) 1585 break; 1586 else if (p == NULL) 1587 pi = ps; 1588 else 1589 pi = MIN(p->pindex, ps); 1590 1591 new_pindex = pi - backing_offset_index; 1592 if (new_pindex >= object->size) 1593 break; 1594 1595 /* 1596 * See if the parent has the page or if the parent's object 1597 * pager has the page. If the parent has the page but the page 1598 * is not valid, the parent's object pager must have the page. 1599 * 1600 * If this fails, the parent does not completely shadow the 1601 * object and we might as well give up now. 1602 */ 1603 pp = vm_page_lookup(object, new_pindex); 1604 if ((pp == NULL || pp->valid == 0) && 1605 !vm_pager_has_page(object, new_pindex, NULL, NULL)) 1606 return (false); 1607 } 1608 return (true); 1609 } 1610 1611 static bool 1612 vm_object_collapse_scan(vm_object_t object, int op) 1613 { 1614 vm_object_t backing_object; 1615 vm_page_t next, p, pp; 1616 vm_pindex_t backing_offset_index, new_pindex; 1617 1618 VM_OBJECT_ASSERT_WLOCKED(object); 1619 VM_OBJECT_ASSERT_WLOCKED(object->backing_object); 1620 1621 backing_object = object->backing_object; 1622 backing_offset_index = OFF_TO_IDX(object->backing_object_offset); 1623 1624 /* 1625 * Initial conditions 1626 */ 1627 if ((op & OBSC_COLLAPSE_WAIT) != 0) 1628 vm_object_set_flag(backing_object, OBJ_DEAD); 1629 1630 /* 1631 * Our scan 1632 */ 1633 for (p = TAILQ_FIRST(&backing_object->memq); p != NULL; p = next) { 1634 next = TAILQ_NEXT(p, listq); 1635 new_pindex = p->pindex - backing_offset_index; 1636 1637 /* 1638 * Check for busy page 1639 */ 1640 if (vm_page_busied(p)) { 1641 next = vm_object_collapse_scan_wait(object, p, next, op); 1642 continue; 1643 } 1644 1645 KASSERT(p->object == backing_object, 1646 ("vm_object_collapse_scan: object mismatch")); 1647 1648 if (p->pindex < backing_offset_index || 1649 new_pindex >= object->size) { 1650 if (backing_object->type == OBJT_SWAP) 1651 swap_pager_freespace(backing_object, p->pindex, 1652 1); 1653 1654 /* 1655 * Page is out of the parent object's range, we can 1656 * simply destroy it. 1657 */ 1658 vm_page_lock(p); 1659 KASSERT(!pmap_page_is_mapped(p), 1660 ("freeing mapped page %p", p)); 1661 if (p->wire_count == 0) 1662 vm_page_free(p); 1663 else 1664 vm_page_remove(p); 1665 vm_page_unlock(p); 1666 continue; 1667 } 1668 1669 pp = vm_page_lookup(object, new_pindex); 1670 if (pp != NULL && vm_page_busied(pp)) { 1671 /* 1672 * The page in the parent is busy and possibly not 1673 * (yet) valid. Until its state is finalized by the 1674 * busy bit owner, we can't tell whether it shadows the 1675 * original page. Therefore, we must either skip it 1676 * and the original (backing_object) page or wait for 1677 * its state to be finalized. 1678 * 1679 * This is due to a race with vm_fault() where we must 1680 * unbusy the original (backing_obj) page before we can 1681 * (re)lock the parent. Hence we can get here. 1682 */ 1683 next = vm_object_collapse_scan_wait(object, pp, next, 1684 op); 1685 continue; 1686 } 1687 1688 KASSERT(pp == NULL || pp->valid != 0, 1689 ("unbusy invalid page %p", pp)); 1690 1691 if (pp != NULL || vm_pager_has_page(object, new_pindex, NULL, 1692 NULL)) { 1693 /* 1694 * The page already exists in the parent OR swap exists 1695 * for this location in the parent. Leave the parent's 1696 * page alone. Destroy the original page from the 1697 * backing object. 1698 */ 1699 if (backing_object->type == OBJT_SWAP) 1700 swap_pager_freespace(backing_object, p->pindex, 1701 1); 1702 vm_page_lock(p); 1703 KASSERT(!pmap_page_is_mapped(p), 1704 ("freeing mapped page %p", p)); 1705 if (p->wire_count == 0) 1706 vm_page_free(p); 1707 else 1708 vm_page_remove(p); 1709 vm_page_unlock(p); 1710 continue; 1711 } 1712 1713 /* 1714 * Page does not exist in parent, rename the page from the 1715 * backing object to the main object. 1716 * 1717 * If the page was mapped to a process, it can remain mapped 1718 * through the rename. vm_page_rename() will dirty the page. 1719 */ 1720 if (vm_page_rename(p, object, new_pindex)) { 1721 next = vm_object_collapse_scan_wait(object, NULL, next, 1722 op); 1723 continue; 1724 } 1725 1726 /* Use the old pindex to free the right page. */ 1727 if (backing_object->type == OBJT_SWAP) 1728 swap_pager_freespace(backing_object, 1729 new_pindex + backing_offset_index, 1); 1730 1731 #if VM_NRESERVLEVEL > 0 1732 /* 1733 * Rename the reservation. 1734 */ 1735 vm_reserv_rename(p, object, backing_object, 1736 backing_offset_index); 1737 #endif 1738 } 1739 return (true); 1740 } 1741 1742 1743 /* 1744 * this version of collapse allows the operation to occur earlier and 1745 * when paging_in_progress is true for an object... This is not a complete 1746 * operation, but should plug 99.9% of the rest of the leaks. 1747 */ 1748 static void 1749 vm_object_qcollapse(vm_object_t object) 1750 { 1751 vm_object_t backing_object = object->backing_object; 1752 1753 VM_OBJECT_ASSERT_WLOCKED(object); 1754 VM_OBJECT_ASSERT_WLOCKED(backing_object); 1755 1756 if (backing_object->ref_count != 1) 1757 return; 1758 1759 vm_object_collapse_scan(object, OBSC_COLLAPSE_NOWAIT); 1760 } 1761 1762 /* 1763 * vm_object_collapse: 1764 * 1765 * Collapse an object with the object backing it. 1766 * Pages in the backing object are moved into the 1767 * parent, and the backing object is deallocated. 1768 */ 1769 void 1770 vm_object_collapse(vm_object_t object) 1771 { 1772 vm_object_t backing_object, new_backing_object; 1773 1774 VM_OBJECT_ASSERT_WLOCKED(object); 1775 1776 while (TRUE) { 1777 /* 1778 * Verify that the conditions are right for collapse: 1779 * 1780 * The object exists and the backing object exists. 1781 */ 1782 if ((backing_object = object->backing_object) == NULL) 1783 break; 1784 1785 /* 1786 * we check the backing object first, because it is most likely 1787 * not collapsable. 1788 */ 1789 VM_OBJECT_WLOCK(backing_object); 1790 if (backing_object->handle != NULL || 1791 (backing_object->type != OBJT_DEFAULT && 1792 backing_object->type != OBJT_SWAP) || 1793 (backing_object->flags & OBJ_DEAD) || 1794 object->handle != NULL || 1795 (object->type != OBJT_DEFAULT && 1796 object->type != OBJT_SWAP) || 1797 (object->flags & OBJ_DEAD)) { 1798 VM_OBJECT_WUNLOCK(backing_object); 1799 break; 1800 } 1801 1802 if (object->paging_in_progress != 0 || 1803 backing_object->paging_in_progress != 0) { 1804 vm_object_qcollapse(object); 1805 VM_OBJECT_WUNLOCK(backing_object); 1806 break; 1807 } 1808 1809 /* 1810 * We know that we can either collapse the backing object (if 1811 * the parent is the only reference to it) or (perhaps) have 1812 * the parent bypass the object if the parent happens to shadow 1813 * all the resident pages in the entire backing object. 1814 * 1815 * This is ignoring pager-backed pages such as swap pages. 1816 * vm_object_collapse_scan fails the shadowing test in this 1817 * case. 1818 */ 1819 if (backing_object->ref_count == 1) { 1820 vm_object_pip_add(object, 1); 1821 vm_object_pip_add(backing_object, 1); 1822 1823 /* 1824 * If there is exactly one reference to the backing 1825 * object, we can collapse it into the parent. 1826 */ 1827 vm_object_collapse_scan(object, OBSC_COLLAPSE_WAIT); 1828 1829 #if VM_NRESERVLEVEL > 0 1830 /* 1831 * Break any reservations from backing_object. 1832 */ 1833 if (__predict_false(!LIST_EMPTY(&backing_object->rvq))) 1834 vm_reserv_break_all(backing_object); 1835 #endif 1836 1837 /* 1838 * Move the pager from backing_object to object. 1839 */ 1840 if (backing_object->type == OBJT_SWAP) { 1841 /* 1842 * swap_pager_copy() can sleep, in which case 1843 * the backing_object's and object's locks are 1844 * released and reacquired. 1845 * Since swap_pager_copy() is being asked to 1846 * destroy the source, it will change the 1847 * backing_object's type to OBJT_DEFAULT. 1848 */ 1849 swap_pager_copy( 1850 backing_object, 1851 object, 1852 OFF_TO_IDX(object->backing_object_offset), TRUE); 1853 } 1854 /* 1855 * Object now shadows whatever backing_object did. 1856 * Note that the reference to 1857 * backing_object->backing_object moves from within 1858 * backing_object to within object. 1859 */ 1860 LIST_REMOVE(object, shadow_list); 1861 backing_object->shadow_count--; 1862 if (backing_object->backing_object) { 1863 VM_OBJECT_WLOCK(backing_object->backing_object); 1864 LIST_REMOVE(backing_object, shadow_list); 1865 LIST_INSERT_HEAD( 1866 &backing_object->backing_object->shadow_head, 1867 object, shadow_list); 1868 /* 1869 * The shadow_count has not changed. 1870 */ 1871 VM_OBJECT_WUNLOCK(backing_object->backing_object); 1872 } 1873 object->backing_object = backing_object->backing_object; 1874 object->backing_object_offset += 1875 backing_object->backing_object_offset; 1876 1877 /* 1878 * Discard backing_object. 1879 * 1880 * Since the backing object has no pages, no pager left, 1881 * and no object references within it, all that is 1882 * necessary is to dispose of it. 1883 */ 1884 KASSERT(backing_object->ref_count == 1, ( 1885 "backing_object %p was somehow re-referenced during collapse!", 1886 backing_object)); 1887 vm_object_pip_wakeup(backing_object); 1888 backing_object->type = OBJT_DEAD; 1889 backing_object->ref_count = 0; 1890 VM_OBJECT_WUNLOCK(backing_object); 1891 vm_object_destroy(backing_object); 1892 1893 vm_object_pip_wakeup(object); 1894 counter_u64_add(object_collapses, 1); 1895 } else { 1896 /* 1897 * If we do not entirely shadow the backing object, 1898 * there is nothing we can do so we give up. 1899 */ 1900 if (object->resident_page_count != object->size && 1901 !vm_object_scan_all_shadowed(object)) { 1902 VM_OBJECT_WUNLOCK(backing_object); 1903 break; 1904 } 1905 1906 /* 1907 * Make the parent shadow the next object in the 1908 * chain. Deallocating backing_object will not remove 1909 * it, since its reference count is at least 2. 1910 */ 1911 LIST_REMOVE(object, shadow_list); 1912 backing_object->shadow_count--; 1913 1914 new_backing_object = backing_object->backing_object; 1915 if ((object->backing_object = new_backing_object) != NULL) { 1916 VM_OBJECT_WLOCK(new_backing_object); 1917 LIST_INSERT_HEAD( 1918 &new_backing_object->shadow_head, 1919 object, 1920 shadow_list 1921 ); 1922 new_backing_object->shadow_count++; 1923 vm_object_reference_locked(new_backing_object); 1924 VM_OBJECT_WUNLOCK(new_backing_object); 1925 object->backing_object_offset += 1926 backing_object->backing_object_offset; 1927 } 1928 1929 /* 1930 * Drop the reference count on backing_object. Since 1931 * its ref_count was at least 2, it will not vanish. 1932 */ 1933 backing_object->ref_count--; 1934 VM_OBJECT_WUNLOCK(backing_object); 1935 counter_u64_add(object_bypasses, 1); 1936 } 1937 1938 /* 1939 * Try again with this object's new backing object. 1940 */ 1941 } 1942 } 1943 1944 /* 1945 * vm_object_page_remove: 1946 * 1947 * For the given object, either frees or invalidates each of the 1948 * specified pages. In general, a page is freed. However, if a page is 1949 * wired for any reason other than the existence of a managed, wired 1950 * mapping, then it may be invalidated but not removed from the object. 1951 * Pages are specified by the given range ["start", "end") and the option 1952 * OBJPR_CLEANONLY. As a special case, if "end" is zero, then the range 1953 * extends from "start" to the end of the object. If the option 1954 * OBJPR_CLEANONLY is specified, then only the non-dirty pages within the 1955 * specified range are affected. If the option OBJPR_NOTMAPPED is 1956 * specified, then the pages within the specified range must have no 1957 * mappings. Otherwise, if this option is not specified, any mappings to 1958 * the specified pages are removed before the pages are freed or 1959 * invalidated. 1960 * 1961 * In general, this operation should only be performed on objects that 1962 * contain managed pages. There are, however, two exceptions. First, it 1963 * is performed on the kernel and kmem objects by vm_map_entry_delete(). 1964 * Second, it is used by msync(..., MS_INVALIDATE) to invalidate device- 1965 * backed pages. In both of these cases, the option OBJPR_CLEANONLY must 1966 * not be specified and the option OBJPR_NOTMAPPED must be specified. 1967 * 1968 * The object must be locked. 1969 */ 1970 void 1971 vm_object_page_remove(vm_object_t object, vm_pindex_t start, vm_pindex_t end, 1972 int options) 1973 { 1974 vm_page_t p, next; 1975 struct mtx *mtx; 1976 struct pglist pgl; 1977 1978 VM_OBJECT_ASSERT_WLOCKED(object); 1979 KASSERT((object->flags & OBJ_UNMANAGED) == 0 || 1980 (options & (OBJPR_CLEANONLY | OBJPR_NOTMAPPED)) == OBJPR_NOTMAPPED, 1981 ("vm_object_page_remove: illegal options for object %p", object)); 1982 if (object->resident_page_count == 0) 1983 return; 1984 vm_object_pip_add(object, 1); 1985 TAILQ_INIT(&pgl); 1986 again: 1987 p = vm_page_find_least(object, start); 1988 mtx = NULL; 1989 1990 /* 1991 * Here, the variable "p" is either (1) the page with the least pindex 1992 * greater than or equal to the parameter "start" or (2) NULL. 1993 */ 1994 for (; p != NULL && (p->pindex < end || end == 0); p = next) { 1995 next = TAILQ_NEXT(p, listq); 1996 1997 /* 1998 * If the page is wired for any reason besides the existence 1999 * of managed, wired mappings, then it cannot be freed. For 2000 * example, fictitious pages, which represent device memory, 2001 * are inherently wired and cannot be freed. They can, 2002 * however, be invalidated if the option OBJPR_CLEANONLY is 2003 * not specified. 2004 */ 2005 vm_page_change_lock(p, &mtx); 2006 if (vm_page_xbusied(p)) { 2007 VM_OBJECT_WUNLOCK(object); 2008 vm_page_busy_sleep(p, "vmopax", true); 2009 VM_OBJECT_WLOCK(object); 2010 goto again; 2011 } 2012 if (p->wire_count != 0) { 2013 if ((options & OBJPR_NOTMAPPED) == 0 && 2014 object->ref_count != 0) 2015 pmap_remove_all(p); 2016 if ((options & OBJPR_CLEANONLY) == 0) { 2017 p->valid = 0; 2018 vm_page_undirty(p); 2019 } 2020 continue; 2021 } 2022 if (vm_page_busied(p)) { 2023 VM_OBJECT_WUNLOCK(object); 2024 vm_page_busy_sleep(p, "vmopar", false); 2025 VM_OBJECT_WLOCK(object); 2026 goto again; 2027 } 2028 KASSERT((p->flags & PG_FICTITIOUS) == 0, 2029 ("vm_object_page_remove: page %p is fictitious", p)); 2030 if ((options & OBJPR_CLEANONLY) != 0 && p->valid != 0) { 2031 if ((options & OBJPR_NOTMAPPED) == 0 && 2032 object->ref_count != 0) 2033 pmap_remove_write(p); 2034 if (p->dirty != 0) 2035 continue; 2036 } 2037 if ((options & OBJPR_NOTMAPPED) == 0 && object->ref_count != 0) 2038 pmap_remove_all(p); 2039 p->flags &= ~PG_ZERO; 2040 if (vm_page_free_prep(p, false)) 2041 TAILQ_INSERT_TAIL(&pgl, p, listq); 2042 } 2043 if (mtx != NULL) 2044 mtx_unlock(mtx); 2045 vm_page_free_phys_pglist(&pgl); 2046 vm_object_pip_wakeup(object); 2047 } 2048 2049 /* 2050 * vm_object_page_noreuse: 2051 * 2052 * For the given object, attempt to move the specified pages to 2053 * the head of the inactive queue. This bypasses regular LRU 2054 * operation and allows the pages to be reused quickly under memory 2055 * pressure. If a page is wired for any reason, then it will not 2056 * be queued. Pages are specified by the range ["start", "end"). 2057 * As a special case, if "end" is zero, then the range extends from 2058 * "start" to the end of the object. 2059 * 2060 * This operation should only be performed on objects that 2061 * contain non-fictitious, managed pages. 2062 * 2063 * The object must be locked. 2064 */ 2065 void 2066 vm_object_page_noreuse(vm_object_t object, vm_pindex_t start, vm_pindex_t end) 2067 { 2068 struct mtx *mtx; 2069 vm_page_t p, next; 2070 2071 VM_OBJECT_ASSERT_LOCKED(object); 2072 KASSERT((object->flags & (OBJ_FICTITIOUS | OBJ_UNMANAGED)) == 0, 2073 ("vm_object_page_noreuse: illegal object %p", object)); 2074 if (object->resident_page_count == 0) 2075 return; 2076 p = vm_page_find_least(object, start); 2077 2078 /* 2079 * Here, the variable "p" is either (1) the page with the least pindex 2080 * greater than or equal to the parameter "start" or (2) NULL. 2081 */ 2082 mtx = NULL; 2083 for (; p != NULL && (p->pindex < end || end == 0); p = next) { 2084 next = TAILQ_NEXT(p, listq); 2085 vm_page_change_lock(p, &mtx); 2086 vm_page_deactivate_noreuse(p); 2087 } 2088 if (mtx != NULL) 2089 mtx_unlock(mtx); 2090 } 2091 2092 /* 2093 * Populate the specified range of the object with valid pages. Returns 2094 * TRUE if the range is successfully populated and FALSE otherwise. 2095 * 2096 * Note: This function should be optimized to pass a larger array of 2097 * pages to vm_pager_get_pages() before it is applied to a non- 2098 * OBJT_DEVICE object. 2099 * 2100 * The object must be locked. 2101 */ 2102 boolean_t 2103 vm_object_populate(vm_object_t object, vm_pindex_t start, vm_pindex_t end) 2104 { 2105 vm_page_t m; 2106 vm_pindex_t pindex; 2107 int rv; 2108 2109 VM_OBJECT_ASSERT_WLOCKED(object); 2110 for (pindex = start; pindex < end; pindex++) { 2111 m = vm_page_grab(object, pindex, VM_ALLOC_NORMAL); 2112 if (m->valid != VM_PAGE_BITS_ALL) { 2113 rv = vm_pager_get_pages(object, &m, 1, NULL, NULL); 2114 if (rv != VM_PAGER_OK) { 2115 vm_page_lock(m); 2116 vm_page_free(m); 2117 vm_page_unlock(m); 2118 break; 2119 } 2120 } 2121 /* 2122 * Keep "m" busy because a subsequent iteration may unlock 2123 * the object. 2124 */ 2125 } 2126 if (pindex > start) { 2127 m = vm_page_lookup(object, start); 2128 while (m != NULL && m->pindex < pindex) { 2129 vm_page_xunbusy(m); 2130 m = TAILQ_NEXT(m, listq); 2131 } 2132 } 2133 return (pindex == end); 2134 } 2135 2136 /* 2137 * Routine: vm_object_coalesce 2138 * Function: Coalesces two objects backing up adjoining 2139 * regions of memory into a single object. 2140 * 2141 * returns TRUE if objects were combined. 2142 * 2143 * NOTE: Only works at the moment if the second object is NULL - 2144 * if it's not, which object do we lock first? 2145 * 2146 * Parameters: 2147 * prev_object First object to coalesce 2148 * prev_offset Offset into prev_object 2149 * prev_size Size of reference to prev_object 2150 * next_size Size of reference to the second object 2151 * reserved Indicator that extension region has 2152 * swap accounted for 2153 * 2154 * Conditions: 2155 * The object must *not* be locked. 2156 */ 2157 boolean_t 2158 vm_object_coalesce(vm_object_t prev_object, vm_ooffset_t prev_offset, 2159 vm_size_t prev_size, vm_size_t next_size, boolean_t reserved) 2160 { 2161 vm_pindex_t next_pindex; 2162 2163 if (prev_object == NULL) 2164 return (TRUE); 2165 VM_OBJECT_WLOCK(prev_object); 2166 if ((prev_object->type != OBJT_DEFAULT && 2167 prev_object->type != OBJT_SWAP) || 2168 (prev_object->flags & OBJ_TMPFS_NODE) != 0) { 2169 VM_OBJECT_WUNLOCK(prev_object); 2170 return (FALSE); 2171 } 2172 2173 /* 2174 * Try to collapse the object first 2175 */ 2176 vm_object_collapse(prev_object); 2177 2178 /* 2179 * Can't coalesce if: . more than one reference . paged out . shadows 2180 * another object . has a copy elsewhere (any of which mean that the 2181 * pages not mapped to prev_entry may be in use anyway) 2182 */ 2183 if (prev_object->backing_object != NULL) { 2184 VM_OBJECT_WUNLOCK(prev_object); 2185 return (FALSE); 2186 } 2187 2188 prev_size >>= PAGE_SHIFT; 2189 next_size >>= PAGE_SHIFT; 2190 next_pindex = OFF_TO_IDX(prev_offset) + prev_size; 2191 2192 if ((prev_object->ref_count > 1) && 2193 (prev_object->size != next_pindex)) { 2194 VM_OBJECT_WUNLOCK(prev_object); 2195 return (FALSE); 2196 } 2197 2198 /* 2199 * Account for the charge. 2200 */ 2201 if (prev_object->cred != NULL) { 2202 2203 /* 2204 * If prev_object was charged, then this mapping, 2205 * although not charged now, may become writable 2206 * later. Non-NULL cred in the object would prevent 2207 * swap reservation during enabling of the write 2208 * access, so reserve swap now. Failed reservation 2209 * cause allocation of the separate object for the map 2210 * entry, and swap reservation for this entry is 2211 * managed in appropriate time. 2212 */ 2213 if (!reserved && !swap_reserve_by_cred(ptoa(next_size), 2214 prev_object->cred)) { 2215 VM_OBJECT_WUNLOCK(prev_object); 2216 return (FALSE); 2217 } 2218 prev_object->charge += ptoa(next_size); 2219 } 2220 2221 /* 2222 * Remove any pages that may still be in the object from a previous 2223 * deallocation. 2224 */ 2225 if (next_pindex < prev_object->size) { 2226 vm_object_page_remove(prev_object, next_pindex, next_pindex + 2227 next_size, 0); 2228 if (prev_object->type == OBJT_SWAP) 2229 swap_pager_freespace(prev_object, 2230 next_pindex, next_size); 2231 #if 0 2232 if (prev_object->cred != NULL) { 2233 KASSERT(prev_object->charge >= 2234 ptoa(prev_object->size - next_pindex), 2235 ("object %p overcharged 1 %jx %jx", prev_object, 2236 (uintmax_t)next_pindex, (uintmax_t)next_size)); 2237 prev_object->charge -= ptoa(prev_object->size - 2238 next_pindex); 2239 } 2240 #endif 2241 } 2242 2243 /* 2244 * Extend the object if necessary. 2245 */ 2246 if (next_pindex + next_size > prev_object->size) 2247 prev_object->size = next_pindex + next_size; 2248 2249 VM_OBJECT_WUNLOCK(prev_object); 2250 return (TRUE); 2251 } 2252 2253 void 2254 vm_object_set_writeable_dirty(vm_object_t object) 2255 { 2256 2257 VM_OBJECT_ASSERT_WLOCKED(object); 2258 if (object->type != OBJT_VNODE) { 2259 if ((object->flags & OBJ_TMPFS_NODE) != 0) { 2260 KASSERT(object->type == OBJT_SWAP, ("non-swap tmpfs")); 2261 vm_object_set_flag(object, OBJ_TMPFS_DIRTY); 2262 } 2263 return; 2264 } 2265 object->generation++; 2266 if ((object->flags & OBJ_MIGHTBEDIRTY) != 0) 2267 return; 2268 vm_object_set_flag(object, OBJ_MIGHTBEDIRTY); 2269 } 2270 2271 /* 2272 * vm_object_unwire: 2273 * 2274 * For each page offset within the specified range of the given object, 2275 * find the highest-level page in the shadow chain and unwire it. A page 2276 * must exist at every page offset, and the highest-level page must be 2277 * wired. 2278 */ 2279 void 2280 vm_object_unwire(vm_object_t object, vm_ooffset_t offset, vm_size_t length, 2281 uint8_t queue) 2282 { 2283 vm_object_t tobject, t1object; 2284 vm_page_t m, tm; 2285 vm_pindex_t end_pindex, pindex, tpindex; 2286 int depth, locked_depth; 2287 2288 KASSERT((offset & PAGE_MASK) == 0, 2289 ("vm_object_unwire: offset is not page aligned")); 2290 KASSERT((length & PAGE_MASK) == 0, 2291 ("vm_object_unwire: length is not a multiple of PAGE_SIZE")); 2292 /* The wired count of a fictitious page never changes. */ 2293 if ((object->flags & OBJ_FICTITIOUS) != 0) 2294 return; 2295 pindex = OFF_TO_IDX(offset); 2296 end_pindex = pindex + atop(length); 2297 again: 2298 locked_depth = 1; 2299 VM_OBJECT_RLOCK(object); 2300 m = vm_page_find_least(object, pindex); 2301 while (pindex < end_pindex) { 2302 if (m == NULL || pindex < m->pindex) { 2303 /* 2304 * The first object in the shadow chain doesn't 2305 * contain a page at the current index. Therefore, 2306 * the page must exist in a backing object. 2307 */ 2308 tobject = object; 2309 tpindex = pindex; 2310 depth = 0; 2311 do { 2312 tpindex += 2313 OFF_TO_IDX(tobject->backing_object_offset); 2314 tobject = tobject->backing_object; 2315 KASSERT(tobject != NULL, 2316 ("vm_object_unwire: missing page")); 2317 if ((tobject->flags & OBJ_FICTITIOUS) != 0) 2318 goto next_page; 2319 depth++; 2320 if (depth == locked_depth) { 2321 locked_depth++; 2322 VM_OBJECT_RLOCK(tobject); 2323 } 2324 } while ((tm = vm_page_lookup(tobject, tpindex)) == 2325 NULL); 2326 } else { 2327 tm = m; 2328 m = TAILQ_NEXT(m, listq); 2329 } 2330 vm_page_lock(tm); 2331 if (vm_page_xbusied(tm)) { 2332 for (tobject = object; locked_depth >= 1; 2333 locked_depth--) { 2334 t1object = tobject->backing_object; 2335 VM_OBJECT_RUNLOCK(tobject); 2336 tobject = t1object; 2337 } 2338 vm_page_busy_sleep(tm, "unwbo", true); 2339 goto again; 2340 } 2341 vm_page_unwire(tm, queue); 2342 vm_page_unlock(tm); 2343 next_page: 2344 pindex++; 2345 } 2346 /* Release the accumulated object locks. */ 2347 for (tobject = object; locked_depth >= 1; locked_depth--) { 2348 t1object = tobject->backing_object; 2349 VM_OBJECT_RUNLOCK(tobject); 2350 tobject = t1object; 2351 } 2352 } 2353 2354 struct vnode * 2355 vm_object_vnode(vm_object_t object) 2356 { 2357 2358 VM_OBJECT_ASSERT_LOCKED(object); 2359 if (object->type == OBJT_VNODE) 2360 return (object->handle); 2361 if (object->type == OBJT_SWAP && (object->flags & OBJ_TMPFS) != 0) 2362 return (object->un_pager.swp.swp_tmpfs); 2363 return (NULL); 2364 } 2365 2366 static int 2367 sysctl_vm_object_list(SYSCTL_HANDLER_ARGS) 2368 { 2369 struct kinfo_vmobject *kvo; 2370 char *fullpath, *freepath; 2371 struct vnode *vp; 2372 struct vattr va; 2373 vm_object_t obj; 2374 vm_page_t m; 2375 int count, error; 2376 2377 if (req->oldptr == NULL) { 2378 /* 2379 * If an old buffer has not been provided, generate an 2380 * estimate of the space needed for a subsequent call. 2381 */ 2382 mtx_lock(&vm_object_list_mtx); 2383 count = 0; 2384 TAILQ_FOREACH(obj, &vm_object_list, object_list) { 2385 if (obj->type == OBJT_DEAD) 2386 continue; 2387 count++; 2388 } 2389 mtx_unlock(&vm_object_list_mtx); 2390 return (SYSCTL_OUT(req, NULL, sizeof(struct kinfo_vmobject) * 2391 count * 11 / 10)); 2392 } 2393 2394 kvo = malloc(sizeof(*kvo), M_TEMP, M_WAITOK); 2395 error = 0; 2396 2397 /* 2398 * VM objects are type stable and are never removed from the 2399 * list once added. This allows us to safely read obj->object_list 2400 * after reacquiring the VM object lock. 2401 */ 2402 mtx_lock(&vm_object_list_mtx); 2403 TAILQ_FOREACH(obj, &vm_object_list, object_list) { 2404 if (obj->type == OBJT_DEAD) 2405 continue; 2406 VM_OBJECT_RLOCK(obj); 2407 if (obj->type == OBJT_DEAD) { 2408 VM_OBJECT_RUNLOCK(obj); 2409 continue; 2410 } 2411 mtx_unlock(&vm_object_list_mtx); 2412 kvo->kvo_size = ptoa(obj->size); 2413 kvo->kvo_resident = obj->resident_page_count; 2414 kvo->kvo_ref_count = obj->ref_count; 2415 kvo->kvo_shadow_count = obj->shadow_count; 2416 kvo->kvo_memattr = obj->memattr; 2417 kvo->kvo_active = 0; 2418 kvo->kvo_inactive = 0; 2419 TAILQ_FOREACH(m, &obj->memq, listq) { 2420 /* 2421 * A page may belong to the object but be 2422 * dequeued and set to PQ_NONE while the 2423 * object lock is not held. This makes the 2424 * reads of m->queue below racy, and we do not 2425 * count pages set to PQ_NONE. However, this 2426 * sysctl is only meant to give an 2427 * approximation of the system anyway. 2428 */ 2429 if (vm_page_active(m)) 2430 kvo->kvo_active++; 2431 else if (vm_page_inactive(m)) 2432 kvo->kvo_inactive++; 2433 } 2434 2435 kvo->kvo_vn_fileid = 0; 2436 kvo->kvo_vn_fsid = 0; 2437 kvo->kvo_vn_fsid_freebsd11 = 0; 2438 freepath = NULL; 2439 fullpath = ""; 2440 vp = NULL; 2441 switch (obj->type) { 2442 case OBJT_DEFAULT: 2443 kvo->kvo_type = KVME_TYPE_DEFAULT; 2444 break; 2445 case OBJT_VNODE: 2446 kvo->kvo_type = KVME_TYPE_VNODE; 2447 vp = obj->handle; 2448 vref(vp); 2449 break; 2450 case OBJT_SWAP: 2451 kvo->kvo_type = KVME_TYPE_SWAP; 2452 break; 2453 case OBJT_DEVICE: 2454 kvo->kvo_type = KVME_TYPE_DEVICE; 2455 break; 2456 case OBJT_PHYS: 2457 kvo->kvo_type = KVME_TYPE_PHYS; 2458 break; 2459 case OBJT_DEAD: 2460 kvo->kvo_type = KVME_TYPE_DEAD; 2461 break; 2462 case OBJT_SG: 2463 kvo->kvo_type = KVME_TYPE_SG; 2464 break; 2465 case OBJT_MGTDEVICE: 2466 kvo->kvo_type = KVME_TYPE_MGTDEVICE; 2467 break; 2468 default: 2469 kvo->kvo_type = KVME_TYPE_UNKNOWN; 2470 break; 2471 } 2472 VM_OBJECT_RUNLOCK(obj); 2473 if (vp != NULL) { 2474 vn_fullpath(curthread, vp, &fullpath, &freepath); 2475 vn_lock(vp, LK_SHARED | LK_RETRY); 2476 if (VOP_GETATTR(vp, &va, curthread->td_ucred) == 0) { 2477 kvo->kvo_vn_fileid = va.va_fileid; 2478 kvo->kvo_vn_fsid = va.va_fsid; 2479 kvo->kvo_vn_fsid_freebsd11 = va.va_fsid; 2480 /* truncate */ 2481 } 2482 vput(vp); 2483 } 2484 2485 strlcpy(kvo->kvo_path, fullpath, sizeof(kvo->kvo_path)); 2486 if (freepath != NULL) 2487 free(freepath, M_TEMP); 2488 2489 /* Pack record size down */ 2490 kvo->kvo_structsize = offsetof(struct kinfo_vmobject, kvo_path) 2491 + strlen(kvo->kvo_path) + 1; 2492 kvo->kvo_structsize = roundup(kvo->kvo_structsize, 2493 sizeof(uint64_t)); 2494 error = SYSCTL_OUT(req, kvo, kvo->kvo_structsize); 2495 mtx_lock(&vm_object_list_mtx); 2496 if (error) 2497 break; 2498 } 2499 mtx_unlock(&vm_object_list_mtx); 2500 free(kvo, M_TEMP); 2501 return (error); 2502 } 2503 SYSCTL_PROC(_vm, OID_AUTO, objects, CTLTYPE_STRUCT | CTLFLAG_RW | CTLFLAG_SKIP | 2504 CTLFLAG_MPSAFE, NULL, 0, sysctl_vm_object_list, "S,kinfo_vmobject", 2505 "List of VM objects"); 2506 2507 #include "opt_ddb.h" 2508 #ifdef DDB 2509 #include <sys/kernel.h> 2510 2511 #include <sys/cons.h> 2512 2513 #include <ddb/ddb.h> 2514 2515 static int 2516 _vm_object_in_map(vm_map_t map, vm_object_t object, vm_map_entry_t entry) 2517 { 2518 vm_map_t tmpm; 2519 vm_map_entry_t tmpe; 2520 vm_object_t obj; 2521 int entcount; 2522 2523 if (map == 0) 2524 return 0; 2525 2526 if (entry == 0) { 2527 tmpe = map->header.next; 2528 entcount = map->nentries; 2529 while (entcount-- && (tmpe != &map->header)) { 2530 if (_vm_object_in_map(map, object, tmpe)) { 2531 return 1; 2532 } 2533 tmpe = tmpe->next; 2534 } 2535 } else if (entry->eflags & MAP_ENTRY_IS_SUB_MAP) { 2536 tmpm = entry->object.sub_map; 2537 tmpe = tmpm->header.next; 2538 entcount = tmpm->nentries; 2539 while (entcount-- && tmpe != &tmpm->header) { 2540 if (_vm_object_in_map(tmpm, object, tmpe)) { 2541 return 1; 2542 } 2543 tmpe = tmpe->next; 2544 } 2545 } else if ((obj = entry->object.vm_object) != NULL) { 2546 for (; obj; obj = obj->backing_object) 2547 if (obj == object) { 2548 return 1; 2549 } 2550 } 2551 return 0; 2552 } 2553 2554 static int 2555 vm_object_in_map(vm_object_t object) 2556 { 2557 struct proc *p; 2558 2559 /* sx_slock(&allproc_lock); */ 2560 FOREACH_PROC_IN_SYSTEM(p) { 2561 if (!p->p_vmspace /* || (p->p_flag & (P_SYSTEM|P_WEXIT)) */) 2562 continue; 2563 if (_vm_object_in_map(&p->p_vmspace->vm_map, object, 0)) { 2564 /* sx_sunlock(&allproc_lock); */ 2565 return 1; 2566 } 2567 } 2568 /* sx_sunlock(&allproc_lock); */ 2569 if (_vm_object_in_map(kernel_map, object, 0)) 2570 return 1; 2571 return 0; 2572 } 2573 2574 DB_SHOW_COMMAND(vmochk, vm_object_check) 2575 { 2576 vm_object_t object; 2577 2578 /* 2579 * make sure that internal objs are in a map somewhere 2580 * and none have zero ref counts. 2581 */ 2582 TAILQ_FOREACH(object, &vm_object_list, object_list) { 2583 if (object->handle == NULL && 2584 (object->type == OBJT_DEFAULT || object->type == OBJT_SWAP)) { 2585 if (object->ref_count == 0) { 2586 db_printf("vmochk: internal obj has zero ref count: %ld\n", 2587 (long)object->size); 2588 } 2589 if (!vm_object_in_map(object)) { 2590 db_printf( 2591 "vmochk: internal obj is not in a map: " 2592 "ref: %d, size: %lu: 0x%lx, backing_object: %p\n", 2593 object->ref_count, (u_long)object->size, 2594 (u_long)object->size, 2595 (void *)object->backing_object); 2596 } 2597 } 2598 } 2599 } 2600 2601 /* 2602 * vm_object_print: [ debug ] 2603 */ 2604 DB_SHOW_COMMAND(object, vm_object_print_static) 2605 { 2606 /* XXX convert args. */ 2607 vm_object_t object = (vm_object_t)addr; 2608 boolean_t full = have_addr; 2609 2610 vm_page_t p; 2611 2612 /* XXX count is an (unused) arg. Avoid shadowing it. */ 2613 #define count was_count 2614 2615 int count; 2616 2617 if (object == NULL) 2618 return; 2619 2620 db_iprintf( 2621 "Object %p: type=%d, size=0x%jx, res=%d, ref=%d, flags=0x%x ruid %d charge %jx\n", 2622 object, (int)object->type, (uintmax_t)object->size, 2623 object->resident_page_count, object->ref_count, object->flags, 2624 object->cred ? object->cred->cr_ruid : -1, (uintmax_t)object->charge); 2625 db_iprintf(" sref=%d, backing_object(%d)=(%p)+0x%jx\n", 2626 object->shadow_count, 2627 object->backing_object ? object->backing_object->ref_count : 0, 2628 object->backing_object, (uintmax_t)object->backing_object_offset); 2629 2630 if (!full) 2631 return; 2632 2633 db_indent += 2; 2634 count = 0; 2635 TAILQ_FOREACH(p, &object->memq, listq) { 2636 if (count == 0) 2637 db_iprintf("memory:="); 2638 else if (count == 6) { 2639 db_printf("\n"); 2640 db_iprintf(" ..."); 2641 count = 0; 2642 } else 2643 db_printf(","); 2644 count++; 2645 2646 db_printf("(off=0x%jx,page=0x%jx)", 2647 (uintmax_t)p->pindex, (uintmax_t)VM_PAGE_TO_PHYS(p)); 2648 } 2649 if (count != 0) 2650 db_printf("\n"); 2651 db_indent -= 2; 2652 } 2653 2654 /* XXX. */ 2655 #undef count 2656 2657 /* XXX need this non-static entry for calling from vm_map_print. */ 2658 void 2659 vm_object_print( 2660 /* db_expr_t */ long addr, 2661 boolean_t have_addr, 2662 /* db_expr_t */ long count, 2663 char *modif) 2664 { 2665 vm_object_print_static(addr, have_addr, count, modif); 2666 } 2667 2668 DB_SHOW_COMMAND(vmopag, vm_object_print_pages) 2669 { 2670 vm_object_t object; 2671 vm_pindex_t fidx; 2672 vm_paddr_t pa; 2673 vm_page_t m, prev_m; 2674 int rcount, nl, c; 2675 2676 nl = 0; 2677 TAILQ_FOREACH(object, &vm_object_list, object_list) { 2678 db_printf("new object: %p\n", (void *)object); 2679 if (nl > 18) { 2680 c = cngetc(); 2681 if (c != ' ') 2682 return; 2683 nl = 0; 2684 } 2685 nl++; 2686 rcount = 0; 2687 fidx = 0; 2688 pa = -1; 2689 TAILQ_FOREACH(m, &object->memq, listq) { 2690 if (m->pindex > 128) 2691 break; 2692 if ((prev_m = TAILQ_PREV(m, pglist, listq)) != NULL && 2693 prev_m->pindex + 1 != m->pindex) { 2694 if (rcount) { 2695 db_printf(" index(%ld)run(%d)pa(0x%lx)\n", 2696 (long)fidx, rcount, (long)pa); 2697 if (nl > 18) { 2698 c = cngetc(); 2699 if (c != ' ') 2700 return; 2701 nl = 0; 2702 } 2703 nl++; 2704 rcount = 0; 2705 } 2706 } 2707 if (rcount && 2708 (VM_PAGE_TO_PHYS(m) == pa + rcount * PAGE_SIZE)) { 2709 ++rcount; 2710 continue; 2711 } 2712 if (rcount) { 2713 db_printf(" index(%ld)run(%d)pa(0x%lx)\n", 2714 (long)fidx, rcount, (long)pa); 2715 if (nl > 18) { 2716 c = cngetc(); 2717 if (c != ' ') 2718 return; 2719 nl = 0; 2720 } 2721 nl++; 2722 } 2723 fidx = m->pindex; 2724 pa = VM_PAGE_TO_PHYS(m); 2725 rcount = 1; 2726 } 2727 if (rcount) { 2728 db_printf(" index(%ld)run(%d)pa(0x%lx)\n", 2729 (long)fidx, rcount, (long)pa); 2730 if (nl > 18) { 2731 c = cngetc(); 2732 if (c != ' ') 2733 return; 2734 nl = 0; 2735 } 2736 nl++; 2737 } 2738 } 2739 } 2740 #endif /* DDB */ 2741