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/blockcount.h> 75 #include <sys/cpuset.h> 76 #include <sys/limits.h> 77 #include <sys/lock.h> 78 #include <sys/mman.h> 79 #include <sys/mount.h> 80 #include <sys/kernel.h> 81 #include <sys/pctrie.h> 82 #include <sys/sysctl.h> 83 #include <sys/mutex.h> 84 #include <sys/proc.h> /* for curproc, pageproc */ 85 #include <sys/refcount.h> 86 #include <sys/socket.h> 87 #include <sys/resourcevar.h> 88 #include <sys/refcount.h> 89 #include <sys/rwlock.h> 90 #include <sys/user.h> 91 #include <sys/vnode.h> 92 #include <sys/vmmeter.h> 93 #include <sys/sx.h> 94 95 #include <vm/vm.h> 96 #include <vm/vm_param.h> 97 #include <vm/pmap.h> 98 #include <vm/vm_map.h> 99 #include <vm/vm_object.h> 100 #include <vm/vm_page.h> 101 #include <vm/vm_pageout.h> 102 #include <vm/vm_pager.h> 103 #include <vm/vm_phys.h> 104 #include <vm/vm_pagequeue.h> 105 #include <vm/swap_pager.h> 106 #include <vm/vm_kern.h> 107 #include <vm/vm_extern.h> 108 #include <vm/vm_radix.h> 109 #include <vm/vm_reserv.h> 110 #include <vm/uma.h> 111 112 static int old_msync; 113 SYSCTL_INT(_vm, OID_AUTO, old_msync, CTLFLAG_RW, &old_msync, 0, 114 "Use old (insecure) msync behavior"); 115 116 static int vm_object_page_collect_flush(vm_object_t object, vm_page_t p, 117 int pagerflags, int flags, boolean_t *allclean, 118 boolean_t *eio); 119 static boolean_t vm_object_page_remove_write(vm_page_t p, int flags, 120 boolean_t *allclean); 121 static void vm_object_backing_remove(vm_object_t object); 122 123 /* 124 * Virtual memory objects maintain the actual data 125 * associated with allocated virtual memory. A given 126 * page of memory exists within exactly one object. 127 * 128 * An object is only deallocated when all "references" 129 * are given up. Only one "reference" to a given 130 * region of an object should be writeable. 131 * 132 * Associated with each object is a list of all resident 133 * memory pages belonging to that object; this list is 134 * maintained by the "vm_page" module, and locked by the object's 135 * lock. 136 * 137 * Each object also records a "pager" routine which is 138 * used to retrieve (and store) pages to the proper backing 139 * storage. In addition, objects may be backed by other 140 * objects from which they were virtual-copied. 141 * 142 * The only items within the object structure which are 143 * modified after time of creation are: 144 * reference count locked by object's lock 145 * pager routine locked by object's lock 146 * 147 */ 148 149 struct object_q vm_object_list; 150 struct mtx vm_object_list_mtx; /* lock for object list and count */ 151 152 struct vm_object kernel_object_store; 153 154 static SYSCTL_NODE(_vm_stats, OID_AUTO, object, CTLFLAG_RD | CTLFLAG_MPSAFE, 0, 155 "VM object stats"); 156 157 static COUNTER_U64_DEFINE_EARLY(object_collapses); 158 SYSCTL_COUNTER_U64(_vm_stats_object, OID_AUTO, collapses, CTLFLAG_RD, 159 &object_collapses, 160 "VM object collapses"); 161 162 static COUNTER_U64_DEFINE_EARLY(object_bypasses); 163 SYSCTL_COUNTER_U64(_vm_stats_object, OID_AUTO, bypasses, CTLFLAG_RD, 164 &object_bypasses, 165 "VM object bypasses"); 166 167 static COUNTER_U64_DEFINE_EARLY(object_collapse_waits); 168 SYSCTL_COUNTER_U64(_vm_stats_object, OID_AUTO, collapse_waits, CTLFLAG_RD, 169 &object_collapse_waits, 170 "Number of sleeps for collapse"); 171 172 static uma_zone_t obj_zone; 173 174 static int vm_object_zinit(void *mem, int size, int flags); 175 176 #ifdef INVARIANTS 177 static void vm_object_zdtor(void *mem, int size, void *arg); 178 179 static void 180 vm_object_zdtor(void *mem, int size, void *arg) 181 { 182 vm_object_t object; 183 184 object = (vm_object_t)mem; 185 KASSERT(object->ref_count == 0, 186 ("object %p ref_count = %d", object, object->ref_count)); 187 KASSERT(TAILQ_EMPTY(&object->memq), 188 ("object %p has resident pages in its memq", object)); 189 KASSERT(vm_radix_is_empty(&object->rtree), 190 ("object %p has resident pages in its trie", object)); 191 #if VM_NRESERVLEVEL > 0 192 KASSERT(LIST_EMPTY(&object->rvq), 193 ("object %p has reservations", 194 object)); 195 #endif 196 KASSERT(!vm_object_busied(object), 197 ("object %p busy = %d", object, blockcount_read(&object->busy))); 198 KASSERT(object->resident_page_count == 0, 199 ("object %p resident_page_count = %d", 200 object, object->resident_page_count)); 201 KASSERT(atomic_load_int(&object->shadow_count) == 0, 202 ("object %p shadow_count = %d", 203 object, atomic_load_int(&object->shadow_count))); 204 KASSERT(object->type == OBJT_DEAD, 205 ("object %p has non-dead type %d", 206 object, object->type)); 207 KASSERT(object->charge == 0 && object->cred == NULL, 208 ("object %p has non-zero charge %ju (%p)", 209 object, (uintmax_t)object->charge, object->cred)); 210 } 211 #endif 212 213 static int 214 vm_object_zinit(void *mem, int size, int flags) 215 { 216 vm_object_t object; 217 218 object = (vm_object_t)mem; 219 rw_init_flags(&object->lock, "vmobject", RW_DUPOK | RW_NEW); 220 221 /* These are true for any object that has been freed */ 222 object->type = OBJT_DEAD; 223 vm_radix_init(&object->rtree); 224 refcount_init(&object->ref_count, 0); 225 blockcount_init(&object->paging_in_progress); 226 blockcount_init(&object->busy); 227 object->resident_page_count = 0; 228 atomic_store_int(&object->shadow_count, 0); 229 object->flags = OBJ_DEAD; 230 231 mtx_lock(&vm_object_list_mtx); 232 TAILQ_INSERT_TAIL(&vm_object_list, object, object_list); 233 mtx_unlock(&vm_object_list_mtx); 234 return (0); 235 } 236 237 static void 238 _vm_object_allocate(objtype_t type, vm_pindex_t size, u_short flags, 239 vm_object_t object, void *handle) 240 { 241 242 TAILQ_INIT(&object->memq); 243 LIST_INIT(&object->shadow_head); 244 245 object->type = type; 246 object->flags = flags; 247 if ((flags & OBJ_SWAP) != 0) { 248 pctrie_init(&object->un_pager.swp.swp_blks); 249 object->un_pager.swp.writemappings = 0; 250 } 251 252 /* 253 * Ensure that swap_pager_swapoff() iteration over object_list 254 * sees up to date type and pctrie head if it observed 255 * non-dead object. 256 */ 257 atomic_thread_fence_rel(); 258 259 object->pg_color = 0; 260 object->size = size; 261 object->domain.dr_policy = NULL; 262 object->generation = 1; 263 object->cleangeneration = 1; 264 refcount_init(&object->ref_count, 1); 265 object->memattr = VM_MEMATTR_DEFAULT; 266 object->cred = NULL; 267 object->charge = 0; 268 object->handle = handle; 269 object->backing_object = NULL; 270 object->backing_object_offset = (vm_ooffset_t) 0; 271 #if VM_NRESERVLEVEL > 0 272 LIST_INIT(&object->rvq); 273 #endif 274 umtx_shm_object_init(object); 275 } 276 277 /* 278 * vm_object_init: 279 * 280 * Initialize the VM objects module. 281 */ 282 void 283 vm_object_init(void) 284 { 285 TAILQ_INIT(&vm_object_list); 286 mtx_init(&vm_object_list_mtx, "vm object_list", NULL, MTX_DEF); 287 288 rw_init(&kernel_object->lock, "kernel vm object"); 289 vm_radix_init(&kernel_object->rtree); 290 _vm_object_allocate(OBJT_PHYS, atop(VM_MAX_KERNEL_ADDRESS - 291 VM_MIN_KERNEL_ADDRESS), OBJ_UNMANAGED, kernel_object, NULL); 292 #if VM_NRESERVLEVEL > 0 293 kernel_object->flags |= OBJ_COLORED; 294 kernel_object->pg_color = (u_short)atop(VM_MIN_KERNEL_ADDRESS); 295 #endif 296 kernel_object->un_pager.phys.ops = &default_phys_pg_ops; 297 298 /* 299 * The lock portion of struct vm_object must be type stable due 300 * to vm_pageout_fallback_object_lock locking a vm object 301 * without holding any references to it. 302 * 303 * paging_in_progress is valid always. Lockless references to 304 * the objects may acquire pip and then check OBJ_DEAD. 305 */ 306 obj_zone = uma_zcreate("VM OBJECT", sizeof (struct vm_object), NULL, 307 #ifdef INVARIANTS 308 vm_object_zdtor, 309 #else 310 NULL, 311 #endif 312 vm_object_zinit, NULL, UMA_ALIGN_PTR, UMA_ZONE_NOFREE); 313 314 vm_radix_zinit(); 315 } 316 317 void 318 vm_object_clear_flag(vm_object_t object, u_short bits) 319 { 320 321 VM_OBJECT_ASSERT_WLOCKED(object); 322 object->flags &= ~bits; 323 } 324 325 /* 326 * Sets the default memory attribute for the specified object. Pages 327 * that are allocated to this object are by default assigned this memory 328 * attribute. 329 * 330 * Presently, this function must be called before any pages are allocated 331 * to the object. In the future, this requirement may be relaxed for 332 * "default" and "swap" objects. 333 */ 334 int 335 vm_object_set_memattr(vm_object_t object, vm_memattr_t memattr) 336 { 337 338 VM_OBJECT_ASSERT_WLOCKED(object); 339 340 if (object->type == OBJT_DEAD) 341 return (KERN_INVALID_ARGUMENT); 342 if (!TAILQ_EMPTY(&object->memq)) 343 return (KERN_FAILURE); 344 345 object->memattr = memattr; 346 return (KERN_SUCCESS); 347 } 348 349 void 350 vm_object_pip_add(vm_object_t object, short i) 351 { 352 353 if (i > 0) 354 blockcount_acquire(&object->paging_in_progress, i); 355 } 356 357 void 358 vm_object_pip_wakeup(vm_object_t object) 359 { 360 361 vm_object_pip_wakeupn(object, 1); 362 } 363 364 void 365 vm_object_pip_wakeupn(vm_object_t object, short i) 366 { 367 368 if (i > 0) 369 blockcount_release(&object->paging_in_progress, i); 370 } 371 372 /* 373 * Atomically drop the object lock and wait for pip to drain. This protects 374 * from sleep/wakeup races due to identity changes. The lock is not re-acquired 375 * on return. 376 */ 377 static void 378 vm_object_pip_sleep(vm_object_t object, const char *waitid) 379 { 380 381 (void)blockcount_sleep(&object->paging_in_progress, &object->lock, 382 waitid, PVM | PDROP); 383 } 384 385 void 386 vm_object_pip_wait(vm_object_t object, const char *waitid) 387 { 388 389 VM_OBJECT_ASSERT_WLOCKED(object); 390 391 blockcount_wait(&object->paging_in_progress, &object->lock, waitid, 392 PVM); 393 } 394 395 void 396 vm_object_pip_wait_unlocked(vm_object_t object, const char *waitid) 397 { 398 399 VM_OBJECT_ASSERT_UNLOCKED(object); 400 401 blockcount_wait(&object->paging_in_progress, NULL, waitid, PVM); 402 } 403 404 /* 405 * vm_object_allocate: 406 * 407 * Returns a new object with the given size. 408 */ 409 vm_object_t 410 vm_object_allocate(objtype_t type, vm_pindex_t size) 411 { 412 vm_object_t object; 413 u_short flags; 414 415 switch (type) { 416 case OBJT_DEAD: 417 panic("vm_object_allocate: can't create OBJT_DEAD"); 418 case OBJT_SWAP: 419 flags = OBJ_COLORED | OBJ_SWAP; 420 break; 421 case OBJT_DEVICE: 422 case OBJT_SG: 423 flags = OBJ_FICTITIOUS | OBJ_UNMANAGED; 424 break; 425 case OBJT_MGTDEVICE: 426 flags = OBJ_FICTITIOUS; 427 break; 428 case OBJT_PHYS: 429 flags = OBJ_UNMANAGED; 430 break; 431 case OBJT_VNODE: 432 flags = 0; 433 break; 434 default: 435 panic("vm_object_allocate: type %d is undefined or dynamic", 436 type); 437 } 438 object = (vm_object_t)uma_zalloc(obj_zone, M_WAITOK); 439 _vm_object_allocate(type, size, flags, object, NULL); 440 441 return (object); 442 } 443 444 vm_object_t 445 vm_object_allocate_dyn(objtype_t dyntype, vm_pindex_t size, u_short flags) 446 { 447 vm_object_t object; 448 449 MPASS(dyntype >= OBJT_FIRST_DYN /* && dyntype < nitems(pagertab) */); 450 object = (vm_object_t)uma_zalloc(obj_zone, M_WAITOK); 451 _vm_object_allocate(dyntype, size, flags, object, NULL); 452 453 return (object); 454 } 455 456 /* 457 * vm_object_allocate_anon: 458 * 459 * Returns a new default object of the given size and marked as 460 * anonymous memory for special split/collapse handling. Color 461 * to be initialized by the caller. 462 */ 463 vm_object_t 464 vm_object_allocate_anon(vm_pindex_t size, vm_object_t backing_object, 465 struct ucred *cred, vm_size_t charge) 466 { 467 vm_object_t handle, object; 468 469 if (backing_object == NULL) 470 handle = NULL; 471 else if ((backing_object->flags & OBJ_ANON) != 0) 472 handle = backing_object->handle; 473 else 474 handle = backing_object; 475 object = uma_zalloc(obj_zone, M_WAITOK); 476 _vm_object_allocate(OBJT_SWAP, size, 477 OBJ_ANON | OBJ_ONEMAPPING | OBJ_SWAP, object, handle); 478 object->cred = cred; 479 object->charge = cred != NULL ? charge : 0; 480 return (object); 481 } 482 483 static void 484 vm_object_reference_vnode(vm_object_t object) 485 { 486 u_int old; 487 488 /* 489 * vnode objects need the lock for the first reference 490 * to serialize with vnode_object_deallocate(). 491 */ 492 if (!refcount_acquire_if_gt(&object->ref_count, 0)) { 493 VM_OBJECT_RLOCK(object); 494 old = refcount_acquire(&object->ref_count); 495 if (object->type == OBJT_VNODE && old == 0) 496 vref(object->handle); 497 VM_OBJECT_RUNLOCK(object); 498 } 499 } 500 501 /* 502 * vm_object_reference: 503 * 504 * Acquires a reference to the given object. 505 */ 506 void 507 vm_object_reference(vm_object_t object) 508 { 509 510 if (object == NULL) 511 return; 512 513 if (object->type == OBJT_VNODE) 514 vm_object_reference_vnode(object); 515 else 516 refcount_acquire(&object->ref_count); 517 KASSERT((object->flags & OBJ_DEAD) == 0, 518 ("vm_object_reference: Referenced dead object.")); 519 } 520 521 /* 522 * vm_object_reference_locked: 523 * 524 * Gets another reference to the given object. 525 * 526 * The object must be locked. 527 */ 528 void 529 vm_object_reference_locked(vm_object_t object) 530 { 531 u_int old; 532 533 VM_OBJECT_ASSERT_LOCKED(object); 534 old = refcount_acquire(&object->ref_count); 535 if (object->type == OBJT_VNODE && old == 0) 536 vref(object->handle); 537 KASSERT((object->flags & OBJ_DEAD) == 0, 538 ("vm_object_reference: Referenced dead object.")); 539 } 540 541 /* 542 * Handle deallocating an object of type OBJT_VNODE. 543 */ 544 static void 545 vm_object_deallocate_vnode(vm_object_t object) 546 { 547 struct vnode *vp = (struct vnode *) object->handle; 548 bool last; 549 550 KASSERT(object->type == OBJT_VNODE, 551 ("vm_object_deallocate_vnode: not a vnode object")); 552 KASSERT(vp != NULL, ("vm_object_deallocate_vnode: missing vp")); 553 554 /* Object lock to protect handle lookup. */ 555 last = refcount_release(&object->ref_count); 556 VM_OBJECT_RUNLOCK(object); 557 558 if (!last) 559 return; 560 561 if (!umtx_shm_vnobj_persistent) 562 umtx_shm_object_terminated(object); 563 564 /* vrele may need the vnode lock. */ 565 vrele(vp); 566 } 567 568 /* 569 * We dropped a reference on an object and discovered that it had a 570 * single remaining shadow. This is a sibling of the reference we 571 * dropped. Attempt to collapse the sibling and backing object. 572 */ 573 static vm_object_t 574 vm_object_deallocate_anon(vm_object_t backing_object) 575 { 576 vm_object_t object; 577 578 /* Fetch the final shadow. */ 579 object = LIST_FIRST(&backing_object->shadow_head); 580 KASSERT(object != NULL && 581 atomic_load_int(&backing_object->shadow_count) == 1, 582 ("vm_object_anon_deallocate: ref_count: %d, shadow_count: %d", 583 backing_object->ref_count, 584 atomic_load_int(&backing_object->shadow_count))); 585 KASSERT((object->flags & OBJ_ANON) != 0, 586 ("invalid shadow object %p", object)); 587 588 if (!VM_OBJECT_TRYWLOCK(object)) { 589 /* 590 * Prevent object from disappearing since we do not have a 591 * reference. 592 */ 593 vm_object_pip_add(object, 1); 594 VM_OBJECT_WUNLOCK(backing_object); 595 VM_OBJECT_WLOCK(object); 596 vm_object_pip_wakeup(object); 597 } else 598 VM_OBJECT_WUNLOCK(backing_object); 599 600 /* 601 * Check for a collapse/terminate race with the last reference holder. 602 */ 603 if ((object->flags & (OBJ_DEAD | OBJ_COLLAPSING)) != 0 || 604 !refcount_acquire_if_not_zero(&object->ref_count)) { 605 VM_OBJECT_WUNLOCK(object); 606 return (NULL); 607 } 608 backing_object = object->backing_object; 609 if (backing_object != NULL && (backing_object->flags & OBJ_ANON) != 0) 610 vm_object_collapse(object); 611 VM_OBJECT_WUNLOCK(object); 612 613 return (object); 614 } 615 616 /* 617 * vm_object_deallocate: 618 * 619 * Release a reference to the specified object, 620 * gained either through a vm_object_allocate 621 * or a vm_object_reference call. When all references 622 * are gone, storage associated with this object 623 * may be relinquished. 624 * 625 * No object may be locked. 626 */ 627 void 628 vm_object_deallocate(vm_object_t object) 629 { 630 vm_object_t temp; 631 bool released; 632 633 while (object != NULL) { 634 /* 635 * If the reference count goes to 0 we start calling 636 * vm_object_terminate() on the object chain. A ref count 637 * of 1 may be a special case depending on the shadow count 638 * being 0 or 1. These cases require a write lock on the 639 * object. 640 */ 641 if ((object->flags & OBJ_ANON) == 0) 642 released = refcount_release_if_gt(&object->ref_count, 1); 643 else 644 released = refcount_release_if_gt(&object->ref_count, 2); 645 if (released) 646 return; 647 648 if (object->type == OBJT_VNODE) { 649 VM_OBJECT_RLOCK(object); 650 if (object->type == OBJT_VNODE) { 651 vm_object_deallocate_vnode(object); 652 return; 653 } 654 VM_OBJECT_RUNLOCK(object); 655 } 656 657 VM_OBJECT_WLOCK(object); 658 KASSERT(object->ref_count > 0, 659 ("vm_object_deallocate: object deallocated too many times: %d", 660 object->type)); 661 662 /* 663 * If this is not the final reference to an anonymous 664 * object we may need to collapse the shadow chain. 665 */ 666 if (!refcount_release(&object->ref_count)) { 667 if (object->ref_count > 1 || 668 atomic_load_int(&object->shadow_count) == 0) { 669 if ((object->flags & OBJ_ANON) != 0 && 670 object->ref_count == 1) 671 vm_object_set_flag(object, 672 OBJ_ONEMAPPING); 673 VM_OBJECT_WUNLOCK(object); 674 return; 675 } 676 677 /* Handle collapsing last ref on anonymous objects. */ 678 object = vm_object_deallocate_anon(object); 679 continue; 680 } 681 682 /* 683 * Handle the final reference to an object. We restart 684 * the loop with the backing object to avoid recursion. 685 */ 686 umtx_shm_object_terminated(object); 687 temp = object->backing_object; 688 if (temp != NULL) { 689 KASSERT(object->type == OBJT_SWAP, 690 ("shadowed tmpfs v_object 2 %p", object)); 691 vm_object_backing_remove(object); 692 } 693 694 KASSERT((object->flags & OBJ_DEAD) == 0, 695 ("vm_object_deallocate: Terminating dead object.")); 696 vm_object_set_flag(object, OBJ_DEAD); 697 vm_object_terminate(object); 698 object = temp; 699 } 700 } 701 702 void 703 vm_object_destroy(vm_object_t object) 704 { 705 uma_zfree(obj_zone, object); 706 } 707 708 static void 709 vm_object_sub_shadow(vm_object_t object) 710 { 711 KASSERT(object->shadow_count >= 1, 712 ("object %p sub_shadow count zero", object)); 713 atomic_subtract_int(&object->shadow_count, 1); 714 } 715 716 static void 717 vm_object_backing_remove_locked(vm_object_t object) 718 { 719 vm_object_t backing_object; 720 721 backing_object = object->backing_object; 722 VM_OBJECT_ASSERT_WLOCKED(object); 723 VM_OBJECT_ASSERT_WLOCKED(backing_object); 724 725 KASSERT((object->flags & OBJ_COLLAPSING) == 0, 726 ("vm_object_backing_remove: Removing collapsing object.")); 727 728 vm_object_sub_shadow(backing_object); 729 if ((object->flags & OBJ_SHADOWLIST) != 0) { 730 LIST_REMOVE(object, shadow_list); 731 vm_object_clear_flag(object, OBJ_SHADOWLIST); 732 } 733 object->backing_object = NULL; 734 } 735 736 static void 737 vm_object_backing_remove(vm_object_t object) 738 { 739 vm_object_t backing_object; 740 741 VM_OBJECT_ASSERT_WLOCKED(object); 742 743 backing_object = object->backing_object; 744 if ((object->flags & OBJ_SHADOWLIST) != 0) { 745 VM_OBJECT_WLOCK(backing_object); 746 vm_object_backing_remove_locked(object); 747 VM_OBJECT_WUNLOCK(backing_object); 748 } else { 749 object->backing_object = NULL; 750 vm_object_sub_shadow(backing_object); 751 } 752 } 753 754 static void 755 vm_object_backing_insert_locked(vm_object_t object, vm_object_t backing_object) 756 { 757 758 VM_OBJECT_ASSERT_WLOCKED(object); 759 760 atomic_add_int(&backing_object->shadow_count, 1); 761 if ((backing_object->flags & OBJ_ANON) != 0) { 762 VM_OBJECT_ASSERT_WLOCKED(backing_object); 763 LIST_INSERT_HEAD(&backing_object->shadow_head, object, 764 shadow_list); 765 vm_object_set_flag(object, OBJ_SHADOWLIST); 766 } 767 object->backing_object = backing_object; 768 } 769 770 static void 771 vm_object_backing_insert(vm_object_t object, vm_object_t backing_object) 772 { 773 774 VM_OBJECT_ASSERT_WLOCKED(object); 775 776 if ((backing_object->flags & OBJ_ANON) != 0) { 777 VM_OBJECT_WLOCK(backing_object); 778 vm_object_backing_insert_locked(object, backing_object); 779 VM_OBJECT_WUNLOCK(backing_object); 780 } else { 781 object->backing_object = backing_object; 782 atomic_add_int(&backing_object->shadow_count, 1); 783 } 784 } 785 786 /* 787 * Insert an object into a backing_object's shadow list with an additional 788 * reference to the backing_object added. 789 */ 790 static void 791 vm_object_backing_insert_ref(vm_object_t object, vm_object_t backing_object) 792 { 793 794 VM_OBJECT_ASSERT_WLOCKED(object); 795 796 if ((backing_object->flags & OBJ_ANON) != 0) { 797 VM_OBJECT_WLOCK(backing_object); 798 KASSERT((backing_object->flags & OBJ_DEAD) == 0, 799 ("shadowing dead anonymous object")); 800 vm_object_reference_locked(backing_object); 801 vm_object_backing_insert_locked(object, backing_object); 802 vm_object_clear_flag(backing_object, OBJ_ONEMAPPING); 803 VM_OBJECT_WUNLOCK(backing_object); 804 } else { 805 vm_object_reference(backing_object); 806 atomic_add_int(&backing_object->shadow_count, 1); 807 object->backing_object = backing_object; 808 } 809 } 810 811 /* 812 * Transfer a backing reference from backing_object to object. 813 */ 814 static void 815 vm_object_backing_transfer(vm_object_t object, vm_object_t backing_object) 816 { 817 vm_object_t new_backing_object; 818 819 /* 820 * Note that the reference to backing_object->backing_object 821 * moves from within backing_object to within object. 822 */ 823 vm_object_backing_remove_locked(object); 824 new_backing_object = backing_object->backing_object; 825 if (new_backing_object == NULL) 826 return; 827 if ((new_backing_object->flags & OBJ_ANON) != 0) { 828 VM_OBJECT_WLOCK(new_backing_object); 829 vm_object_backing_remove_locked(backing_object); 830 vm_object_backing_insert_locked(object, new_backing_object); 831 VM_OBJECT_WUNLOCK(new_backing_object); 832 } else { 833 /* 834 * shadow_count for new_backing_object is left 835 * unchanged, its reference provided by backing_object 836 * is replaced by object. 837 */ 838 object->backing_object = new_backing_object; 839 backing_object->backing_object = NULL; 840 } 841 } 842 843 /* 844 * Wait for a concurrent collapse to settle. 845 */ 846 static void 847 vm_object_collapse_wait(vm_object_t object) 848 { 849 850 VM_OBJECT_ASSERT_WLOCKED(object); 851 852 while ((object->flags & OBJ_COLLAPSING) != 0) { 853 vm_object_pip_wait(object, "vmcolwait"); 854 counter_u64_add(object_collapse_waits, 1); 855 } 856 } 857 858 /* 859 * Waits for a backing object to clear a pending collapse and returns 860 * it locked if it is an ANON object. 861 */ 862 static vm_object_t 863 vm_object_backing_collapse_wait(vm_object_t object) 864 { 865 vm_object_t backing_object; 866 867 VM_OBJECT_ASSERT_WLOCKED(object); 868 869 for (;;) { 870 backing_object = object->backing_object; 871 if (backing_object == NULL || 872 (backing_object->flags & OBJ_ANON) == 0) 873 return (NULL); 874 VM_OBJECT_WLOCK(backing_object); 875 if ((backing_object->flags & (OBJ_DEAD | OBJ_COLLAPSING)) == 0) 876 break; 877 VM_OBJECT_WUNLOCK(object); 878 vm_object_pip_sleep(backing_object, "vmbckwait"); 879 counter_u64_add(object_collapse_waits, 1); 880 VM_OBJECT_WLOCK(object); 881 } 882 return (backing_object); 883 } 884 885 /* 886 * vm_object_terminate_pages removes any remaining pageable pages 887 * from the object and resets the object to an empty state. 888 */ 889 static void 890 vm_object_terminate_pages(vm_object_t object) 891 { 892 vm_page_t p, p_next; 893 894 VM_OBJECT_ASSERT_WLOCKED(object); 895 896 /* 897 * Free any remaining pageable pages. This also removes them from the 898 * paging queues. However, don't free wired pages, just remove them 899 * from the object. Rather than incrementally removing each page from 900 * the object, the page and object are reset to any empty state. 901 */ 902 TAILQ_FOREACH_SAFE(p, &object->memq, listq, p_next) { 903 vm_page_assert_unbusied(p); 904 KASSERT(p->object == object && 905 (p->ref_count & VPRC_OBJREF) != 0, 906 ("vm_object_terminate_pages: page %p is inconsistent", p)); 907 908 p->object = NULL; 909 if (vm_page_drop(p, VPRC_OBJREF) == VPRC_OBJREF) { 910 VM_CNT_INC(v_pfree); 911 vm_page_free(p); 912 } 913 } 914 915 /* 916 * If the object contained any pages, then reset it to an empty state. 917 * None of the object's fields, including "resident_page_count", were 918 * modified by the preceding loop. 919 */ 920 if (object->resident_page_count != 0) { 921 vm_radix_reclaim_allnodes(&object->rtree); 922 TAILQ_INIT(&object->memq); 923 object->resident_page_count = 0; 924 if (object->type == OBJT_VNODE) 925 vdrop(object->handle); 926 } 927 } 928 929 /* 930 * vm_object_terminate actually destroys the specified object, freeing 931 * up all previously used resources. 932 * 933 * The object must be locked. 934 * This routine may block. 935 */ 936 void 937 vm_object_terminate(vm_object_t object) 938 { 939 940 VM_OBJECT_ASSERT_WLOCKED(object); 941 KASSERT((object->flags & OBJ_DEAD) != 0, 942 ("terminating non-dead obj %p", object)); 943 KASSERT((object->flags & OBJ_COLLAPSING) == 0, 944 ("terminating collapsing obj %p", object)); 945 KASSERT(object->backing_object == NULL, 946 ("terminating shadow obj %p", object)); 947 948 /* 949 * Wait for the pageout daemon and other current users to be 950 * done with the object. Note that new paging_in_progress 951 * users can come after this wait, but they must check 952 * OBJ_DEAD flag set (without unlocking the object), and avoid 953 * the object being terminated. 954 */ 955 vm_object_pip_wait(object, "objtrm"); 956 957 KASSERT(object->ref_count == 0, 958 ("vm_object_terminate: object with references, ref_count=%d", 959 object->ref_count)); 960 961 if ((object->flags & OBJ_PG_DTOR) == 0) 962 vm_object_terminate_pages(object); 963 964 #if VM_NRESERVLEVEL > 0 965 if (__predict_false(!LIST_EMPTY(&object->rvq))) 966 vm_reserv_break_all(object); 967 #endif 968 969 KASSERT(object->cred == NULL || (object->flags & OBJ_SWAP) != 0, 970 ("%s: non-swap obj %p has cred", __func__, object)); 971 972 /* 973 * Let the pager know object is dead. 974 */ 975 vm_pager_deallocate(object); 976 VM_OBJECT_WUNLOCK(object); 977 978 vm_object_destroy(object); 979 } 980 981 /* 982 * Make the page read-only so that we can clear the object flags. However, if 983 * this is a nosync mmap then the object is likely to stay dirty so do not 984 * mess with the page and do not clear the object flags. Returns TRUE if the 985 * page should be flushed, and FALSE otherwise. 986 */ 987 static boolean_t 988 vm_object_page_remove_write(vm_page_t p, int flags, boolean_t *allclean) 989 { 990 991 vm_page_assert_busied(p); 992 993 /* 994 * If we have been asked to skip nosync pages and this is a 995 * nosync page, skip it. Note that the object flags were not 996 * cleared in this case so we do not have to set them. 997 */ 998 if ((flags & OBJPC_NOSYNC) != 0 && (p->a.flags & PGA_NOSYNC) != 0) { 999 *allclean = FALSE; 1000 return (FALSE); 1001 } else { 1002 pmap_remove_write(p); 1003 return (p->dirty != 0); 1004 } 1005 } 1006 1007 /* 1008 * vm_object_page_clean 1009 * 1010 * Clean all dirty pages in the specified range of object. Leaves page 1011 * on whatever queue it is currently on. If NOSYNC is set then do not 1012 * write out pages with PGA_NOSYNC set (originally comes from MAP_NOSYNC), 1013 * leaving the object dirty. 1014 * 1015 * For swap objects backing tmpfs regular files, do not flush anything, 1016 * but remove write protection on the mapped pages to update mtime through 1017 * mmaped writes. 1018 * 1019 * When stuffing pages asynchronously, allow clustering. XXX we need a 1020 * synchronous clustering mode implementation. 1021 * 1022 * Odd semantics: if start == end, we clean everything. 1023 * 1024 * The object must be locked. 1025 * 1026 * Returns FALSE if some page from the range was not written, as 1027 * reported by the pager, and TRUE otherwise. 1028 */ 1029 boolean_t 1030 vm_object_page_clean(vm_object_t object, vm_ooffset_t start, vm_ooffset_t end, 1031 int flags) 1032 { 1033 vm_page_t np, p; 1034 vm_pindex_t pi, tend, tstart; 1035 int curgeneration, n, pagerflags; 1036 boolean_t eio, res, allclean; 1037 1038 VM_OBJECT_ASSERT_WLOCKED(object); 1039 1040 if (!vm_object_mightbedirty(object) || object->resident_page_count == 0) 1041 return (TRUE); 1042 1043 pagerflags = (flags & (OBJPC_SYNC | OBJPC_INVAL)) != 0 ? 1044 VM_PAGER_PUT_SYNC : VM_PAGER_CLUSTER_OK; 1045 pagerflags |= (flags & OBJPC_INVAL) != 0 ? VM_PAGER_PUT_INVAL : 0; 1046 1047 tstart = OFF_TO_IDX(start); 1048 tend = (end == 0) ? object->size : OFF_TO_IDX(end + PAGE_MASK); 1049 allclean = tstart == 0 && tend >= object->size; 1050 res = TRUE; 1051 1052 rescan: 1053 curgeneration = object->generation; 1054 1055 for (p = vm_page_find_least(object, tstart); p != NULL; p = np) { 1056 pi = p->pindex; 1057 if (pi >= tend) 1058 break; 1059 np = TAILQ_NEXT(p, listq); 1060 if (vm_page_none_valid(p)) 1061 continue; 1062 if (vm_page_busy_acquire(p, VM_ALLOC_WAITFAIL) == 0) { 1063 if (object->generation != curgeneration && 1064 (flags & OBJPC_SYNC) != 0) 1065 goto rescan; 1066 np = vm_page_find_least(object, pi); 1067 continue; 1068 } 1069 if (!vm_object_page_remove_write(p, flags, &allclean)) { 1070 vm_page_xunbusy(p); 1071 continue; 1072 } 1073 if (object->type == OBJT_VNODE) { 1074 n = vm_object_page_collect_flush(object, p, pagerflags, 1075 flags, &allclean, &eio); 1076 if (eio) { 1077 res = FALSE; 1078 allclean = FALSE; 1079 } 1080 if (object->generation != curgeneration && 1081 (flags & OBJPC_SYNC) != 0) 1082 goto rescan; 1083 1084 /* 1085 * If the VOP_PUTPAGES() did a truncated write, so 1086 * that even the first page of the run is not fully 1087 * written, vm_pageout_flush() returns 0 as the run 1088 * length. Since the condition that caused truncated 1089 * write may be permanent, e.g. exhausted free space, 1090 * accepting n == 0 would cause an infinite loop. 1091 * 1092 * Forwarding the iterator leaves the unwritten page 1093 * behind, but there is not much we can do there if 1094 * filesystem refuses to write it. 1095 */ 1096 if (n == 0) { 1097 n = 1; 1098 allclean = FALSE; 1099 } 1100 } else { 1101 n = 1; 1102 vm_page_xunbusy(p); 1103 } 1104 np = vm_page_find_least(object, pi + n); 1105 } 1106 #if 0 1107 VOP_FSYNC(vp, (pagerflags & VM_PAGER_PUT_SYNC) ? MNT_WAIT : 0); 1108 #endif 1109 1110 /* 1111 * Leave updating cleangeneration for tmpfs objects to tmpfs 1112 * scan. It needs to update mtime, which happens for other 1113 * filesystems during page writeouts. 1114 */ 1115 if (allclean && object->type == OBJT_VNODE) 1116 object->cleangeneration = curgeneration; 1117 return (res); 1118 } 1119 1120 static int 1121 vm_object_page_collect_flush(vm_object_t object, vm_page_t p, int pagerflags, 1122 int flags, boolean_t *allclean, boolean_t *eio) 1123 { 1124 vm_page_t ma[vm_pageout_page_count], p_first, tp; 1125 int count, i, mreq, runlen; 1126 1127 vm_page_lock_assert(p, MA_NOTOWNED); 1128 vm_page_assert_xbusied(p); 1129 VM_OBJECT_ASSERT_WLOCKED(object); 1130 1131 count = 1; 1132 mreq = 0; 1133 1134 for (tp = p; count < vm_pageout_page_count; count++) { 1135 tp = vm_page_next(tp); 1136 if (tp == NULL || vm_page_tryxbusy(tp) == 0) 1137 break; 1138 if (!vm_object_page_remove_write(tp, flags, allclean)) { 1139 vm_page_xunbusy(tp); 1140 break; 1141 } 1142 } 1143 1144 for (p_first = p; count < vm_pageout_page_count; count++) { 1145 tp = vm_page_prev(p_first); 1146 if (tp == NULL || vm_page_tryxbusy(tp) == 0) 1147 break; 1148 if (!vm_object_page_remove_write(tp, flags, allclean)) { 1149 vm_page_xunbusy(tp); 1150 break; 1151 } 1152 p_first = tp; 1153 mreq++; 1154 } 1155 1156 for (tp = p_first, i = 0; i < count; tp = TAILQ_NEXT(tp, listq), i++) 1157 ma[i] = tp; 1158 1159 vm_pageout_flush(ma, count, pagerflags, mreq, &runlen, eio); 1160 return (runlen); 1161 } 1162 1163 /* 1164 * Note that there is absolutely no sense in writing out 1165 * anonymous objects, so we track down the vnode object 1166 * to write out. 1167 * We invalidate (remove) all pages from the address space 1168 * for semantic correctness. 1169 * 1170 * If the backing object is a device object with unmanaged pages, then any 1171 * mappings to the specified range of pages must be removed before this 1172 * function is called. 1173 * 1174 * Note: certain anonymous maps, such as MAP_NOSYNC maps, 1175 * may start out with a NULL object. 1176 */ 1177 boolean_t 1178 vm_object_sync(vm_object_t object, vm_ooffset_t offset, vm_size_t size, 1179 boolean_t syncio, boolean_t invalidate) 1180 { 1181 vm_object_t backing_object; 1182 struct vnode *vp; 1183 struct mount *mp; 1184 int error, flags, fsync_after; 1185 boolean_t res; 1186 1187 if (object == NULL) 1188 return (TRUE); 1189 res = TRUE; 1190 error = 0; 1191 VM_OBJECT_WLOCK(object); 1192 while ((backing_object = object->backing_object) != NULL) { 1193 VM_OBJECT_WLOCK(backing_object); 1194 offset += object->backing_object_offset; 1195 VM_OBJECT_WUNLOCK(object); 1196 object = backing_object; 1197 if (object->size < OFF_TO_IDX(offset + size)) 1198 size = IDX_TO_OFF(object->size) - offset; 1199 } 1200 /* 1201 * Flush pages if writing is allowed, invalidate them 1202 * if invalidation requested. Pages undergoing I/O 1203 * will be ignored by vm_object_page_remove(). 1204 * 1205 * We cannot lock the vnode and then wait for paging 1206 * to complete without deadlocking against vm_fault. 1207 * Instead we simply call vm_object_page_remove() and 1208 * allow it to block internally on a page-by-page 1209 * basis when it encounters pages undergoing async 1210 * I/O. 1211 */ 1212 if (object->type == OBJT_VNODE && 1213 vm_object_mightbedirty(object) != 0 && 1214 ((vp = object->handle)->v_vflag & VV_NOSYNC) == 0) { 1215 VM_OBJECT_WUNLOCK(object); 1216 (void)vn_start_write(vp, &mp, V_WAIT); 1217 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY); 1218 if (syncio && !invalidate && offset == 0 && 1219 atop(size) == object->size) { 1220 /* 1221 * If syncing the whole mapping of the file, 1222 * it is faster to schedule all the writes in 1223 * async mode, also allowing the clustering, 1224 * and then wait for i/o to complete. 1225 */ 1226 flags = 0; 1227 fsync_after = TRUE; 1228 } else { 1229 flags = (syncio || invalidate) ? OBJPC_SYNC : 0; 1230 flags |= invalidate ? (OBJPC_SYNC | OBJPC_INVAL) : 0; 1231 fsync_after = FALSE; 1232 } 1233 VM_OBJECT_WLOCK(object); 1234 res = vm_object_page_clean(object, offset, offset + size, 1235 flags); 1236 VM_OBJECT_WUNLOCK(object); 1237 if (fsync_after) { 1238 for (;;) { 1239 error = VOP_FSYNC(vp, MNT_WAIT, curthread); 1240 if (error != ERELOOKUP) 1241 break; 1242 1243 /* 1244 * Allow SU/bufdaemon to handle more 1245 * dependencies in the meantime. 1246 */ 1247 VOP_UNLOCK(vp); 1248 vn_finished_write(mp); 1249 1250 (void)vn_start_write(vp, &mp, V_WAIT); 1251 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY); 1252 } 1253 } 1254 VOP_UNLOCK(vp); 1255 vn_finished_write(mp); 1256 if (error != 0) 1257 res = FALSE; 1258 VM_OBJECT_WLOCK(object); 1259 } 1260 if ((object->type == OBJT_VNODE || 1261 object->type == OBJT_DEVICE) && invalidate) { 1262 if (object->type == OBJT_DEVICE) 1263 /* 1264 * The option OBJPR_NOTMAPPED must be passed here 1265 * because vm_object_page_remove() cannot remove 1266 * unmanaged mappings. 1267 */ 1268 flags = OBJPR_NOTMAPPED; 1269 else if (old_msync) 1270 flags = 0; 1271 else 1272 flags = OBJPR_CLEANONLY; 1273 vm_object_page_remove(object, OFF_TO_IDX(offset), 1274 OFF_TO_IDX(offset + size + PAGE_MASK), flags); 1275 } 1276 VM_OBJECT_WUNLOCK(object); 1277 return (res); 1278 } 1279 1280 /* 1281 * Determine whether the given advice can be applied to the object. Advice is 1282 * not applied to unmanaged pages since they never belong to page queues, and 1283 * since MADV_FREE is destructive, it can apply only to anonymous pages that 1284 * have been mapped at most once. 1285 */ 1286 static bool 1287 vm_object_advice_applies(vm_object_t object, int advice) 1288 { 1289 1290 if ((object->flags & OBJ_UNMANAGED) != 0) 1291 return (false); 1292 if (advice != MADV_FREE) 1293 return (true); 1294 return ((object->flags & (OBJ_ONEMAPPING | OBJ_ANON)) == 1295 (OBJ_ONEMAPPING | OBJ_ANON)); 1296 } 1297 1298 static void 1299 vm_object_madvise_freespace(vm_object_t object, int advice, vm_pindex_t pindex, 1300 vm_size_t size) 1301 { 1302 1303 if (advice == MADV_FREE) 1304 vm_pager_freespace(object, pindex, size); 1305 } 1306 1307 /* 1308 * vm_object_madvise: 1309 * 1310 * Implements the madvise function at the object/page level. 1311 * 1312 * MADV_WILLNEED (any object) 1313 * 1314 * Activate the specified pages if they are resident. 1315 * 1316 * MADV_DONTNEED (any object) 1317 * 1318 * Deactivate the specified pages if they are resident. 1319 * 1320 * MADV_FREE (OBJT_SWAP objects, OBJ_ONEMAPPING only) 1321 * 1322 * Deactivate and clean the specified pages if they are 1323 * resident. This permits the process to reuse the pages 1324 * without faulting or the kernel to reclaim the pages 1325 * without I/O. 1326 */ 1327 void 1328 vm_object_madvise(vm_object_t object, vm_pindex_t pindex, vm_pindex_t end, 1329 int advice) 1330 { 1331 vm_pindex_t tpindex; 1332 vm_object_t backing_object, tobject; 1333 vm_page_t m, tm; 1334 1335 if (object == NULL) 1336 return; 1337 1338 relookup: 1339 VM_OBJECT_WLOCK(object); 1340 if (!vm_object_advice_applies(object, advice)) { 1341 VM_OBJECT_WUNLOCK(object); 1342 return; 1343 } 1344 for (m = vm_page_find_least(object, pindex); pindex < end; pindex++) { 1345 tobject = object; 1346 1347 /* 1348 * If the next page isn't resident in the top-level object, we 1349 * need to search the shadow chain. When applying MADV_FREE, we 1350 * take care to release any swap space used to store 1351 * non-resident pages. 1352 */ 1353 if (m == NULL || pindex < m->pindex) { 1354 /* 1355 * Optimize a common case: if the top-level object has 1356 * no backing object, we can skip over the non-resident 1357 * range in constant time. 1358 */ 1359 if (object->backing_object == NULL) { 1360 tpindex = (m != NULL && m->pindex < end) ? 1361 m->pindex : end; 1362 vm_object_madvise_freespace(object, advice, 1363 pindex, tpindex - pindex); 1364 if ((pindex = tpindex) == end) 1365 break; 1366 goto next_page; 1367 } 1368 1369 tpindex = pindex; 1370 do { 1371 vm_object_madvise_freespace(tobject, advice, 1372 tpindex, 1); 1373 /* 1374 * Prepare to search the next object in the 1375 * chain. 1376 */ 1377 backing_object = tobject->backing_object; 1378 if (backing_object == NULL) 1379 goto next_pindex; 1380 VM_OBJECT_WLOCK(backing_object); 1381 tpindex += 1382 OFF_TO_IDX(tobject->backing_object_offset); 1383 if (tobject != object) 1384 VM_OBJECT_WUNLOCK(tobject); 1385 tobject = backing_object; 1386 if (!vm_object_advice_applies(tobject, advice)) 1387 goto next_pindex; 1388 } while ((tm = vm_page_lookup(tobject, tpindex)) == 1389 NULL); 1390 } else { 1391 next_page: 1392 tm = m; 1393 m = TAILQ_NEXT(m, listq); 1394 } 1395 1396 /* 1397 * If the page is not in a normal state, skip it. The page 1398 * can not be invalidated while the object lock is held. 1399 */ 1400 if (!vm_page_all_valid(tm) || vm_page_wired(tm)) 1401 goto next_pindex; 1402 KASSERT((tm->flags & PG_FICTITIOUS) == 0, 1403 ("vm_object_madvise: page %p is fictitious", tm)); 1404 KASSERT((tm->oflags & VPO_UNMANAGED) == 0, 1405 ("vm_object_madvise: page %p is not managed", tm)); 1406 if (vm_page_tryxbusy(tm) == 0) { 1407 if (object != tobject) 1408 VM_OBJECT_WUNLOCK(object); 1409 if (advice == MADV_WILLNEED) { 1410 /* 1411 * Reference the page before unlocking and 1412 * sleeping so that the page daemon is less 1413 * likely to reclaim it. 1414 */ 1415 vm_page_aflag_set(tm, PGA_REFERENCED); 1416 } 1417 if (!vm_page_busy_sleep(tm, "madvpo", 0)) 1418 VM_OBJECT_WUNLOCK(tobject); 1419 goto relookup; 1420 } 1421 vm_page_advise(tm, advice); 1422 vm_page_xunbusy(tm); 1423 vm_object_madvise_freespace(tobject, advice, tm->pindex, 1); 1424 next_pindex: 1425 if (tobject != object) 1426 VM_OBJECT_WUNLOCK(tobject); 1427 } 1428 VM_OBJECT_WUNLOCK(object); 1429 } 1430 1431 /* 1432 * vm_object_shadow: 1433 * 1434 * Create a new object which is backed by the 1435 * specified existing object range. The source 1436 * object reference is deallocated. 1437 * 1438 * The new object and offset into that object 1439 * are returned in the source parameters. 1440 */ 1441 void 1442 vm_object_shadow(vm_object_t *object, vm_ooffset_t *offset, vm_size_t length, 1443 struct ucred *cred, bool shared) 1444 { 1445 vm_object_t source; 1446 vm_object_t result; 1447 1448 source = *object; 1449 1450 /* 1451 * Don't create the new object if the old object isn't shared. 1452 * 1453 * If we hold the only reference we can guarantee that it won't 1454 * increase while we have the map locked. Otherwise the race is 1455 * harmless and we will end up with an extra shadow object that 1456 * will be collapsed later. 1457 */ 1458 if (source != NULL && source->ref_count == 1 && 1459 (source->flags & OBJ_ANON) != 0) 1460 return; 1461 1462 /* 1463 * Allocate a new object with the given length. 1464 */ 1465 result = vm_object_allocate_anon(atop(length), source, cred, length); 1466 1467 /* 1468 * Store the offset into the source object, and fix up the offset into 1469 * the new object. 1470 */ 1471 result->backing_object_offset = *offset; 1472 1473 if (shared || source != NULL) { 1474 VM_OBJECT_WLOCK(result); 1475 1476 /* 1477 * The new object shadows the source object, adding a 1478 * reference to it. Our caller changes his reference 1479 * to point to the new object, removing a reference to 1480 * the source object. Net result: no change of 1481 * reference count, unless the caller needs to add one 1482 * more reference due to forking a shared map entry. 1483 */ 1484 if (shared) { 1485 vm_object_reference_locked(result); 1486 vm_object_clear_flag(result, OBJ_ONEMAPPING); 1487 } 1488 1489 /* 1490 * Try to optimize the result object's page color when 1491 * shadowing in order to maintain page coloring 1492 * consistency in the combined shadowed object. 1493 */ 1494 if (source != NULL) { 1495 vm_object_backing_insert(result, source); 1496 result->domain = source->domain; 1497 #if VM_NRESERVLEVEL > 0 1498 vm_object_set_flag(result, 1499 (source->flags & OBJ_COLORED)); 1500 result->pg_color = (source->pg_color + 1501 OFF_TO_IDX(*offset)) & ((1 << (VM_NFREEORDER - 1502 1)) - 1); 1503 #endif 1504 } 1505 VM_OBJECT_WUNLOCK(result); 1506 } 1507 1508 /* 1509 * Return the new things 1510 */ 1511 *offset = 0; 1512 *object = result; 1513 } 1514 1515 /* 1516 * vm_object_split: 1517 * 1518 * Split the pages in a map entry into a new object. This affords 1519 * easier removal of unused pages, and keeps object inheritance from 1520 * being a negative impact on memory usage. 1521 */ 1522 void 1523 vm_object_split(vm_map_entry_t entry) 1524 { 1525 vm_page_t m, m_next; 1526 vm_object_t orig_object, new_object, backing_object; 1527 vm_pindex_t idx, offidxstart; 1528 vm_size_t size; 1529 1530 orig_object = entry->object.vm_object; 1531 KASSERT((orig_object->flags & OBJ_ONEMAPPING) != 0, 1532 ("vm_object_split: Splitting object with multiple mappings.")); 1533 if ((orig_object->flags & OBJ_ANON) == 0) 1534 return; 1535 if (orig_object->ref_count <= 1) 1536 return; 1537 VM_OBJECT_WUNLOCK(orig_object); 1538 1539 offidxstart = OFF_TO_IDX(entry->offset); 1540 size = atop(entry->end - entry->start); 1541 1542 new_object = vm_object_allocate_anon(size, orig_object, 1543 orig_object->cred, ptoa(size)); 1544 1545 /* 1546 * We must wait for the orig_object to complete any in-progress 1547 * collapse so that the swap blocks are stable below. The 1548 * additional reference on backing_object by new object will 1549 * prevent further collapse operations until split completes. 1550 */ 1551 VM_OBJECT_WLOCK(orig_object); 1552 vm_object_collapse_wait(orig_object); 1553 1554 /* 1555 * At this point, the new object is still private, so the order in 1556 * which the original and new objects are locked does not matter. 1557 */ 1558 VM_OBJECT_WLOCK(new_object); 1559 new_object->domain = orig_object->domain; 1560 backing_object = orig_object->backing_object; 1561 if (backing_object != NULL) { 1562 vm_object_backing_insert_ref(new_object, backing_object); 1563 new_object->backing_object_offset = 1564 orig_object->backing_object_offset + entry->offset; 1565 } 1566 if (orig_object->cred != NULL) { 1567 crhold(orig_object->cred); 1568 KASSERT(orig_object->charge >= ptoa(size), 1569 ("orig_object->charge < 0")); 1570 orig_object->charge -= ptoa(size); 1571 } 1572 1573 /* 1574 * Mark the split operation so that swap_pager_getpages() knows 1575 * that the object is in transition. 1576 */ 1577 vm_object_set_flag(orig_object, OBJ_SPLIT); 1578 #ifdef INVARIANTS 1579 idx = 0; 1580 #endif 1581 retry: 1582 m = vm_page_find_least(orig_object, offidxstart); 1583 KASSERT(m == NULL || idx <= m->pindex - offidxstart, 1584 ("%s: object %p was repopulated", __func__, orig_object)); 1585 for (; m != NULL && (idx = m->pindex - offidxstart) < size; 1586 m = m_next) { 1587 m_next = TAILQ_NEXT(m, listq); 1588 1589 /* 1590 * We must wait for pending I/O to complete before we can 1591 * rename the page. 1592 * 1593 * We do not have to VM_PROT_NONE the page as mappings should 1594 * not be changed by this operation. 1595 */ 1596 if (vm_page_tryxbusy(m) == 0) { 1597 VM_OBJECT_WUNLOCK(new_object); 1598 if (vm_page_busy_sleep(m, "spltwt", 0)) 1599 VM_OBJECT_WLOCK(orig_object); 1600 VM_OBJECT_WLOCK(new_object); 1601 goto retry; 1602 } 1603 1604 /* 1605 * The page was left invalid. Likely placed there by 1606 * an incomplete fault. Just remove and ignore. 1607 */ 1608 if (vm_page_none_valid(m)) { 1609 if (vm_page_remove(m)) 1610 vm_page_free(m); 1611 continue; 1612 } 1613 1614 /* vm_page_rename() will dirty the page. */ 1615 if (vm_page_rename(m, new_object, idx)) { 1616 vm_page_xunbusy(m); 1617 VM_OBJECT_WUNLOCK(new_object); 1618 VM_OBJECT_WUNLOCK(orig_object); 1619 vm_radix_wait(); 1620 VM_OBJECT_WLOCK(orig_object); 1621 VM_OBJECT_WLOCK(new_object); 1622 goto retry; 1623 } 1624 1625 #if VM_NRESERVLEVEL > 0 1626 /* 1627 * If some of the reservation's allocated pages remain with 1628 * the original object, then transferring the reservation to 1629 * the new object is neither particularly beneficial nor 1630 * particularly harmful as compared to leaving the reservation 1631 * with the original object. If, however, all of the 1632 * reservation's allocated pages are transferred to the new 1633 * object, then transferring the reservation is typically 1634 * beneficial. Determining which of these two cases applies 1635 * would be more costly than unconditionally renaming the 1636 * reservation. 1637 */ 1638 vm_reserv_rename(m, new_object, orig_object, offidxstart); 1639 #endif 1640 } 1641 1642 /* 1643 * swap_pager_copy() can sleep, in which case the orig_object's 1644 * and new_object's locks are released and reacquired. 1645 */ 1646 swap_pager_copy(orig_object, new_object, offidxstart, 0); 1647 1648 TAILQ_FOREACH(m, &new_object->memq, listq) 1649 vm_page_xunbusy(m); 1650 1651 vm_object_clear_flag(orig_object, OBJ_SPLIT); 1652 VM_OBJECT_WUNLOCK(orig_object); 1653 VM_OBJECT_WUNLOCK(new_object); 1654 entry->object.vm_object = new_object; 1655 entry->offset = 0LL; 1656 vm_object_deallocate(orig_object); 1657 VM_OBJECT_WLOCK(new_object); 1658 } 1659 1660 static vm_page_t 1661 vm_object_collapse_scan_wait(vm_object_t object, vm_page_t p) 1662 { 1663 vm_object_t backing_object; 1664 1665 VM_OBJECT_ASSERT_WLOCKED(object); 1666 backing_object = object->backing_object; 1667 VM_OBJECT_ASSERT_WLOCKED(backing_object); 1668 1669 KASSERT(p == NULL || p->object == object || p->object == backing_object, 1670 ("invalid ownership %p %p %p", p, object, backing_object)); 1671 /* The page is only NULL when rename fails. */ 1672 if (p == NULL) { 1673 VM_OBJECT_WUNLOCK(object); 1674 VM_OBJECT_WUNLOCK(backing_object); 1675 vm_radix_wait(); 1676 VM_OBJECT_WLOCK(object); 1677 } else if (p->object == object) { 1678 VM_OBJECT_WUNLOCK(backing_object); 1679 if (vm_page_busy_sleep(p, "vmocol", 0)) 1680 VM_OBJECT_WLOCK(object); 1681 } else { 1682 VM_OBJECT_WUNLOCK(object); 1683 if (!vm_page_busy_sleep(p, "vmocol", 0)) 1684 VM_OBJECT_WUNLOCK(backing_object); 1685 VM_OBJECT_WLOCK(object); 1686 } 1687 VM_OBJECT_WLOCK(backing_object); 1688 return (TAILQ_FIRST(&backing_object->memq)); 1689 } 1690 1691 static bool 1692 vm_object_scan_all_shadowed(vm_object_t object) 1693 { 1694 vm_object_t backing_object; 1695 vm_page_t p, pp; 1696 vm_pindex_t backing_offset_index, new_pindex, pi, ps; 1697 1698 VM_OBJECT_ASSERT_WLOCKED(object); 1699 VM_OBJECT_ASSERT_WLOCKED(object->backing_object); 1700 1701 backing_object = object->backing_object; 1702 1703 if ((backing_object->flags & OBJ_ANON) == 0) 1704 return (false); 1705 1706 pi = backing_offset_index = OFF_TO_IDX(object->backing_object_offset); 1707 p = vm_page_find_least(backing_object, pi); 1708 ps = swap_pager_find_least(backing_object, pi); 1709 1710 /* 1711 * Only check pages inside the parent object's range and 1712 * inside the parent object's mapping of the backing object. 1713 */ 1714 for (;; pi++) { 1715 if (p != NULL && p->pindex < pi) 1716 p = TAILQ_NEXT(p, listq); 1717 if (ps < pi) 1718 ps = swap_pager_find_least(backing_object, pi); 1719 if (p == NULL && ps >= backing_object->size) 1720 break; 1721 else if (p == NULL) 1722 pi = ps; 1723 else 1724 pi = MIN(p->pindex, ps); 1725 1726 new_pindex = pi - backing_offset_index; 1727 if (new_pindex >= object->size) 1728 break; 1729 1730 if (p != NULL) { 1731 /* 1732 * If the backing object page is busy a 1733 * grandparent or older page may still be 1734 * undergoing CoW. It is not safe to collapse 1735 * the backing object until it is quiesced. 1736 */ 1737 if (vm_page_tryxbusy(p) == 0) 1738 return (false); 1739 1740 /* 1741 * We raced with the fault handler that left 1742 * newly allocated invalid page on the object 1743 * queue and retried. 1744 */ 1745 if (!vm_page_all_valid(p)) 1746 goto unbusy_ret; 1747 } 1748 1749 /* 1750 * See if the parent has the page or if the parent's object 1751 * pager has the page. If the parent has the page but the page 1752 * is not valid, the parent's object pager must have the page. 1753 * 1754 * If this fails, the parent does not completely shadow the 1755 * object and we might as well give up now. 1756 */ 1757 pp = vm_page_lookup(object, new_pindex); 1758 1759 /* 1760 * The valid check here is stable due to object lock 1761 * being required to clear valid and initiate paging. 1762 * Busy of p disallows fault handler to validate pp. 1763 */ 1764 if ((pp == NULL || vm_page_none_valid(pp)) && 1765 !vm_pager_has_page(object, new_pindex, NULL, NULL)) 1766 goto unbusy_ret; 1767 if (p != NULL) 1768 vm_page_xunbusy(p); 1769 } 1770 return (true); 1771 1772 unbusy_ret: 1773 if (p != NULL) 1774 vm_page_xunbusy(p); 1775 return (false); 1776 } 1777 1778 static void 1779 vm_object_collapse_scan(vm_object_t object) 1780 { 1781 vm_object_t backing_object; 1782 vm_page_t next, p, pp; 1783 vm_pindex_t backing_offset_index, new_pindex; 1784 1785 VM_OBJECT_ASSERT_WLOCKED(object); 1786 VM_OBJECT_ASSERT_WLOCKED(object->backing_object); 1787 1788 backing_object = object->backing_object; 1789 backing_offset_index = OFF_TO_IDX(object->backing_object_offset); 1790 1791 /* 1792 * Our scan 1793 */ 1794 for (p = TAILQ_FIRST(&backing_object->memq); p != NULL; p = next) { 1795 next = TAILQ_NEXT(p, listq); 1796 new_pindex = p->pindex - backing_offset_index; 1797 1798 /* 1799 * Check for busy page 1800 */ 1801 if (vm_page_tryxbusy(p) == 0) { 1802 next = vm_object_collapse_scan_wait(object, p); 1803 continue; 1804 } 1805 1806 KASSERT(object->backing_object == backing_object, 1807 ("vm_object_collapse_scan: backing object mismatch %p != %p", 1808 object->backing_object, backing_object)); 1809 KASSERT(p->object == backing_object, 1810 ("vm_object_collapse_scan: object mismatch %p != %p", 1811 p->object, backing_object)); 1812 1813 if (p->pindex < backing_offset_index || 1814 new_pindex >= object->size) { 1815 vm_pager_freespace(backing_object, p->pindex, 1); 1816 1817 KASSERT(!pmap_page_is_mapped(p), 1818 ("freeing mapped page %p", p)); 1819 if (vm_page_remove(p)) 1820 vm_page_free(p); 1821 continue; 1822 } 1823 1824 if (!vm_page_all_valid(p)) { 1825 KASSERT(!pmap_page_is_mapped(p), 1826 ("freeing mapped page %p", p)); 1827 if (vm_page_remove(p)) 1828 vm_page_free(p); 1829 continue; 1830 } 1831 1832 pp = vm_page_lookup(object, new_pindex); 1833 if (pp != NULL && vm_page_tryxbusy(pp) == 0) { 1834 vm_page_xunbusy(p); 1835 /* 1836 * The page in the parent is busy and possibly not 1837 * (yet) valid. Until its state is finalized by the 1838 * busy bit owner, we can't tell whether it shadows the 1839 * original page. 1840 */ 1841 next = vm_object_collapse_scan_wait(object, pp); 1842 continue; 1843 } 1844 1845 if (pp != NULL && vm_page_none_valid(pp)) { 1846 /* 1847 * The page was invalid in the parent. Likely placed 1848 * there by an incomplete fault. Just remove and 1849 * ignore. p can replace it. 1850 */ 1851 if (vm_page_remove(pp)) 1852 vm_page_free(pp); 1853 pp = NULL; 1854 } 1855 1856 if (pp != NULL || vm_pager_has_page(object, new_pindex, NULL, 1857 NULL)) { 1858 /* 1859 * The page already exists in the parent OR swap exists 1860 * for this location in the parent. Leave the parent's 1861 * page alone. Destroy the original page from the 1862 * backing object. 1863 */ 1864 vm_pager_freespace(backing_object, p->pindex, 1); 1865 KASSERT(!pmap_page_is_mapped(p), 1866 ("freeing mapped page %p", p)); 1867 if (vm_page_remove(p)) 1868 vm_page_free(p); 1869 if (pp != NULL) 1870 vm_page_xunbusy(pp); 1871 continue; 1872 } 1873 1874 /* 1875 * Page does not exist in parent, rename the page from the 1876 * backing object to the main object. 1877 * 1878 * If the page was mapped to a process, it can remain mapped 1879 * through the rename. vm_page_rename() will dirty the page. 1880 */ 1881 if (vm_page_rename(p, object, new_pindex)) { 1882 vm_page_xunbusy(p); 1883 next = vm_object_collapse_scan_wait(object, NULL); 1884 continue; 1885 } 1886 1887 /* Use the old pindex to free the right page. */ 1888 vm_pager_freespace(backing_object, new_pindex + 1889 backing_offset_index, 1); 1890 1891 #if VM_NRESERVLEVEL > 0 1892 /* 1893 * Rename the reservation. 1894 */ 1895 vm_reserv_rename(p, object, backing_object, 1896 backing_offset_index); 1897 #endif 1898 vm_page_xunbusy(p); 1899 } 1900 return; 1901 } 1902 1903 /* 1904 * vm_object_collapse: 1905 * 1906 * Collapse an object with the object backing it. 1907 * Pages in the backing object are moved into the 1908 * parent, and the backing object is deallocated. 1909 */ 1910 void 1911 vm_object_collapse(vm_object_t object) 1912 { 1913 vm_object_t backing_object, new_backing_object; 1914 1915 VM_OBJECT_ASSERT_WLOCKED(object); 1916 1917 while (TRUE) { 1918 KASSERT((object->flags & (OBJ_DEAD | OBJ_ANON)) == OBJ_ANON, 1919 ("collapsing invalid object")); 1920 1921 /* 1922 * Wait for the backing_object to finish any pending 1923 * collapse so that the caller sees the shortest possible 1924 * shadow chain. 1925 */ 1926 backing_object = vm_object_backing_collapse_wait(object); 1927 if (backing_object == NULL) 1928 return; 1929 1930 KASSERT(object->ref_count > 0 && 1931 object->ref_count > atomic_load_int(&object->shadow_count), 1932 ("collapse with invalid ref %d or shadow %d count.", 1933 object->ref_count, atomic_load_int(&object->shadow_count))); 1934 KASSERT((backing_object->flags & 1935 (OBJ_COLLAPSING | OBJ_DEAD)) == 0, 1936 ("vm_object_collapse: Backing object already collapsing.")); 1937 KASSERT((object->flags & (OBJ_COLLAPSING | OBJ_DEAD)) == 0, 1938 ("vm_object_collapse: object is already collapsing.")); 1939 1940 /* 1941 * We know that we can either collapse the backing object if 1942 * the parent is the only reference to it, or (perhaps) have 1943 * the parent bypass the object if the parent happens to shadow 1944 * all the resident pages in the entire backing object. 1945 */ 1946 if (backing_object->ref_count == 1) { 1947 KASSERT(atomic_load_int(&backing_object->shadow_count) 1948 == 1, 1949 ("vm_object_collapse: shadow_count: %d", 1950 atomic_load_int(&backing_object->shadow_count))); 1951 vm_object_pip_add(object, 1); 1952 vm_object_set_flag(object, OBJ_COLLAPSING); 1953 vm_object_pip_add(backing_object, 1); 1954 vm_object_set_flag(backing_object, OBJ_DEAD); 1955 1956 /* 1957 * If there is exactly one reference to the backing 1958 * object, we can collapse it into the parent. 1959 */ 1960 vm_object_collapse_scan(object); 1961 1962 #if VM_NRESERVLEVEL > 0 1963 /* 1964 * Break any reservations from backing_object. 1965 */ 1966 if (__predict_false(!LIST_EMPTY(&backing_object->rvq))) 1967 vm_reserv_break_all(backing_object); 1968 #endif 1969 1970 /* 1971 * Move the pager from backing_object to object. 1972 * 1973 * swap_pager_copy() can sleep, in which case the 1974 * backing_object's and object's locks are released and 1975 * reacquired. 1976 */ 1977 swap_pager_copy(backing_object, object, 1978 OFF_TO_IDX(object->backing_object_offset), TRUE); 1979 1980 /* 1981 * Object now shadows whatever backing_object did. 1982 */ 1983 vm_object_clear_flag(object, OBJ_COLLAPSING); 1984 vm_object_backing_transfer(object, backing_object); 1985 object->backing_object_offset += 1986 backing_object->backing_object_offset; 1987 VM_OBJECT_WUNLOCK(object); 1988 vm_object_pip_wakeup(object); 1989 1990 /* 1991 * Discard backing_object. 1992 * 1993 * Since the backing object has no pages, no pager left, 1994 * and no object references within it, all that is 1995 * necessary is to dispose of it. 1996 */ 1997 KASSERT(backing_object->ref_count == 1, ( 1998 "backing_object %p was somehow re-referenced during collapse!", 1999 backing_object)); 2000 vm_object_pip_wakeup(backing_object); 2001 (void)refcount_release(&backing_object->ref_count); 2002 vm_object_terminate(backing_object); 2003 counter_u64_add(object_collapses, 1); 2004 VM_OBJECT_WLOCK(object); 2005 } else { 2006 /* 2007 * If we do not entirely shadow the backing object, 2008 * there is nothing we can do so we give up. 2009 * 2010 * The object lock and backing_object lock must not 2011 * be dropped during this sequence. 2012 */ 2013 if (!vm_object_scan_all_shadowed(object)) { 2014 VM_OBJECT_WUNLOCK(backing_object); 2015 break; 2016 } 2017 2018 /* 2019 * Make the parent shadow the next object in the 2020 * chain. Deallocating backing_object will not remove 2021 * it, since its reference count is at least 2. 2022 */ 2023 vm_object_backing_remove_locked(object); 2024 new_backing_object = backing_object->backing_object; 2025 if (new_backing_object != NULL) { 2026 vm_object_backing_insert_ref(object, 2027 new_backing_object); 2028 object->backing_object_offset += 2029 backing_object->backing_object_offset; 2030 } 2031 2032 /* 2033 * Drop the reference count on backing_object. Since 2034 * its ref_count was at least 2, it will not vanish. 2035 */ 2036 (void)refcount_release(&backing_object->ref_count); 2037 KASSERT(backing_object->ref_count >= 1, ( 2038 "backing_object %p was somehow dereferenced during collapse!", 2039 backing_object)); 2040 VM_OBJECT_WUNLOCK(backing_object); 2041 counter_u64_add(object_bypasses, 1); 2042 } 2043 2044 /* 2045 * Try again with this object's new backing object. 2046 */ 2047 } 2048 } 2049 2050 /* 2051 * vm_object_page_remove: 2052 * 2053 * For the given object, either frees or invalidates each of the 2054 * specified pages. In general, a page is freed. However, if a page is 2055 * wired for any reason other than the existence of a managed, wired 2056 * mapping, then it may be invalidated but not removed from the object. 2057 * Pages are specified by the given range ["start", "end") and the option 2058 * OBJPR_CLEANONLY. As a special case, if "end" is zero, then the range 2059 * extends from "start" to the end of the object. If the option 2060 * OBJPR_CLEANONLY is specified, then only the non-dirty pages within the 2061 * specified range are affected. If the option OBJPR_NOTMAPPED is 2062 * specified, then the pages within the specified range must have no 2063 * mappings. Otherwise, if this option is not specified, any mappings to 2064 * the specified pages are removed before the pages are freed or 2065 * invalidated. 2066 * 2067 * In general, this operation should only be performed on objects that 2068 * contain managed pages. There are, however, two exceptions. First, it 2069 * is performed on the kernel and kmem objects by vm_map_entry_delete(). 2070 * Second, it is used by msync(..., MS_INVALIDATE) to invalidate device- 2071 * backed pages. In both of these cases, the option OBJPR_CLEANONLY must 2072 * not be specified and the option OBJPR_NOTMAPPED must be specified. 2073 * 2074 * The object must be locked. 2075 */ 2076 void 2077 vm_object_page_remove(vm_object_t object, vm_pindex_t start, vm_pindex_t end, 2078 int options) 2079 { 2080 vm_page_t p, next; 2081 2082 VM_OBJECT_ASSERT_WLOCKED(object); 2083 KASSERT((object->flags & OBJ_UNMANAGED) == 0 || 2084 (options & (OBJPR_CLEANONLY | OBJPR_NOTMAPPED)) == OBJPR_NOTMAPPED, 2085 ("vm_object_page_remove: illegal options for object %p", object)); 2086 if (object->resident_page_count == 0) 2087 return; 2088 vm_object_pip_add(object, 1); 2089 again: 2090 p = vm_page_find_least(object, start); 2091 2092 /* 2093 * Here, the variable "p" is either (1) the page with the least pindex 2094 * greater than or equal to the parameter "start" or (2) NULL. 2095 */ 2096 for (; p != NULL && (p->pindex < end || end == 0); p = next) { 2097 next = TAILQ_NEXT(p, listq); 2098 2099 /* 2100 * Skip invalid pages if asked to do so. Try to avoid acquiring 2101 * the busy lock, as some consumers rely on this to avoid 2102 * deadlocks. 2103 * 2104 * A thread may concurrently transition the page from invalid to 2105 * valid using only the busy lock, so the result of this check 2106 * is immediately stale. It is up to consumers to handle this, 2107 * for instance by ensuring that all invalid->valid transitions 2108 * happen with a mutex held, as may be possible for a 2109 * filesystem. 2110 */ 2111 if ((options & OBJPR_VALIDONLY) != 0 && vm_page_none_valid(p)) 2112 continue; 2113 2114 /* 2115 * If the page is wired for any reason besides the existence 2116 * of managed, wired mappings, then it cannot be freed. For 2117 * example, fictitious pages, which represent device memory, 2118 * are inherently wired and cannot be freed. They can, 2119 * however, be invalidated if the option OBJPR_CLEANONLY is 2120 * not specified. 2121 */ 2122 if (vm_page_tryxbusy(p) == 0) { 2123 if (vm_page_busy_sleep(p, "vmopar", 0)) 2124 VM_OBJECT_WLOCK(object); 2125 goto again; 2126 } 2127 if ((options & OBJPR_VALIDONLY) != 0 && vm_page_none_valid(p)) { 2128 vm_page_xunbusy(p); 2129 continue; 2130 } 2131 if (vm_page_wired(p)) { 2132 wired: 2133 if ((options & OBJPR_NOTMAPPED) == 0 && 2134 object->ref_count != 0) 2135 pmap_remove_all(p); 2136 if ((options & OBJPR_CLEANONLY) == 0) { 2137 vm_page_invalid(p); 2138 vm_page_undirty(p); 2139 } 2140 vm_page_xunbusy(p); 2141 continue; 2142 } 2143 KASSERT((p->flags & PG_FICTITIOUS) == 0, 2144 ("vm_object_page_remove: page %p is fictitious", p)); 2145 if ((options & OBJPR_CLEANONLY) != 0 && 2146 !vm_page_none_valid(p)) { 2147 if ((options & OBJPR_NOTMAPPED) == 0 && 2148 object->ref_count != 0 && 2149 !vm_page_try_remove_write(p)) 2150 goto wired; 2151 if (p->dirty != 0) { 2152 vm_page_xunbusy(p); 2153 continue; 2154 } 2155 } 2156 if ((options & OBJPR_NOTMAPPED) == 0 && 2157 object->ref_count != 0 && !vm_page_try_remove_all(p)) 2158 goto wired; 2159 vm_page_free(p); 2160 } 2161 vm_object_pip_wakeup(object); 2162 2163 vm_pager_freespace(object, start, (end == 0 ? object->size : end) - 2164 start); 2165 } 2166 2167 /* 2168 * vm_object_page_noreuse: 2169 * 2170 * For the given object, attempt to move the specified pages to 2171 * the head of the inactive queue. This bypasses regular LRU 2172 * operation and allows the pages to be reused quickly under memory 2173 * pressure. If a page is wired for any reason, then it will not 2174 * be queued. Pages are specified by the range ["start", "end"). 2175 * As a special case, if "end" is zero, then the range extends from 2176 * "start" to the end of the object. 2177 * 2178 * This operation should only be performed on objects that 2179 * contain non-fictitious, managed pages. 2180 * 2181 * The object must be locked. 2182 */ 2183 void 2184 vm_object_page_noreuse(vm_object_t object, vm_pindex_t start, vm_pindex_t end) 2185 { 2186 vm_page_t p, next; 2187 2188 VM_OBJECT_ASSERT_LOCKED(object); 2189 KASSERT((object->flags & (OBJ_FICTITIOUS | OBJ_UNMANAGED)) == 0, 2190 ("vm_object_page_noreuse: illegal object %p", object)); 2191 if (object->resident_page_count == 0) 2192 return; 2193 p = vm_page_find_least(object, start); 2194 2195 /* 2196 * Here, the variable "p" is either (1) the page with the least pindex 2197 * greater than or equal to the parameter "start" or (2) NULL. 2198 */ 2199 for (; p != NULL && (p->pindex < end || end == 0); p = next) { 2200 next = TAILQ_NEXT(p, listq); 2201 vm_page_deactivate_noreuse(p); 2202 } 2203 } 2204 2205 /* 2206 * Populate the specified range of the object with valid pages. Returns 2207 * TRUE if the range is successfully populated and FALSE otherwise. 2208 * 2209 * Note: This function should be optimized to pass a larger array of 2210 * pages to vm_pager_get_pages() before it is applied to a non- 2211 * OBJT_DEVICE object. 2212 * 2213 * The object must be locked. 2214 */ 2215 boolean_t 2216 vm_object_populate(vm_object_t object, vm_pindex_t start, vm_pindex_t end) 2217 { 2218 vm_page_t m; 2219 vm_pindex_t pindex; 2220 int rv; 2221 2222 VM_OBJECT_ASSERT_WLOCKED(object); 2223 for (pindex = start; pindex < end; pindex++) { 2224 rv = vm_page_grab_valid(&m, object, pindex, VM_ALLOC_NORMAL); 2225 if (rv != VM_PAGER_OK) 2226 break; 2227 2228 /* 2229 * Keep "m" busy because a subsequent iteration may unlock 2230 * the object. 2231 */ 2232 } 2233 if (pindex > start) { 2234 m = vm_page_lookup(object, start); 2235 while (m != NULL && m->pindex < pindex) { 2236 vm_page_xunbusy(m); 2237 m = TAILQ_NEXT(m, listq); 2238 } 2239 } 2240 return (pindex == end); 2241 } 2242 2243 /* 2244 * Routine: vm_object_coalesce 2245 * Function: Coalesces two objects backing up adjoining 2246 * regions of memory into a single object. 2247 * 2248 * returns TRUE if objects were combined. 2249 * 2250 * NOTE: Only works at the moment if the second object is NULL - 2251 * if it's not, which object do we lock first? 2252 * 2253 * Parameters: 2254 * prev_object First object to coalesce 2255 * prev_offset Offset into prev_object 2256 * prev_size Size of reference to prev_object 2257 * next_size Size of reference to the second object 2258 * reserved Indicator that extension region has 2259 * swap accounted for 2260 * 2261 * Conditions: 2262 * The object must *not* be locked. 2263 */ 2264 boolean_t 2265 vm_object_coalesce(vm_object_t prev_object, vm_ooffset_t prev_offset, 2266 vm_size_t prev_size, vm_size_t next_size, boolean_t reserved) 2267 { 2268 vm_pindex_t next_pindex; 2269 2270 if (prev_object == NULL) 2271 return (TRUE); 2272 if ((prev_object->flags & OBJ_ANON) == 0) 2273 return (FALSE); 2274 2275 VM_OBJECT_WLOCK(prev_object); 2276 /* 2277 * Try to collapse the object first. 2278 */ 2279 vm_object_collapse(prev_object); 2280 2281 /* 2282 * Can't coalesce if: . more than one reference . paged out . shadows 2283 * another object . has a copy elsewhere (any of which mean that the 2284 * pages not mapped to prev_entry may be in use anyway) 2285 */ 2286 if (prev_object->backing_object != NULL) { 2287 VM_OBJECT_WUNLOCK(prev_object); 2288 return (FALSE); 2289 } 2290 2291 prev_size >>= PAGE_SHIFT; 2292 next_size >>= PAGE_SHIFT; 2293 next_pindex = OFF_TO_IDX(prev_offset) + prev_size; 2294 2295 if (prev_object->ref_count > 1 && 2296 prev_object->size != next_pindex && 2297 (prev_object->flags & OBJ_ONEMAPPING) == 0) { 2298 VM_OBJECT_WUNLOCK(prev_object); 2299 return (FALSE); 2300 } 2301 2302 /* 2303 * Account for the charge. 2304 */ 2305 if (prev_object->cred != NULL) { 2306 /* 2307 * If prev_object was charged, then this mapping, 2308 * although not charged now, may become writable 2309 * later. Non-NULL cred in the object would prevent 2310 * swap reservation during enabling of the write 2311 * access, so reserve swap now. Failed reservation 2312 * cause allocation of the separate object for the map 2313 * entry, and swap reservation for this entry is 2314 * managed in appropriate time. 2315 */ 2316 if (!reserved && !swap_reserve_by_cred(ptoa(next_size), 2317 prev_object->cred)) { 2318 VM_OBJECT_WUNLOCK(prev_object); 2319 return (FALSE); 2320 } 2321 prev_object->charge += ptoa(next_size); 2322 } 2323 2324 /* 2325 * Remove any pages that may still be in the object from a previous 2326 * deallocation. 2327 */ 2328 if (next_pindex < prev_object->size) { 2329 vm_object_page_remove(prev_object, next_pindex, next_pindex + 2330 next_size, 0); 2331 #if 0 2332 if (prev_object->cred != NULL) { 2333 KASSERT(prev_object->charge >= 2334 ptoa(prev_object->size - next_pindex), 2335 ("object %p overcharged 1 %jx %jx", prev_object, 2336 (uintmax_t)next_pindex, (uintmax_t)next_size)); 2337 prev_object->charge -= ptoa(prev_object->size - 2338 next_pindex); 2339 } 2340 #endif 2341 } 2342 2343 /* 2344 * Extend the object if necessary. 2345 */ 2346 if (next_pindex + next_size > prev_object->size) 2347 prev_object->size = next_pindex + next_size; 2348 2349 VM_OBJECT_WUNLOCK(prev_object); 2350 return (TRUE); 2351 } 2352 2353 void 2354 vm_object_set_writeable_dirty_(vm_object_t object) 2355 { 2356 atomic_add_int(&object->generation, 1); 2357 } 2358 2359 bool 2360 vm_object_mightbedirty_(vm_object_t object) 2361 { 2362 return (object->generation != object->cleangeneration); 2363 } 2364 2365 /* 2366 * vm_object_unwire: 2367 * 2368 * For each page offset within the specified range of the given object, 2369 * find the highest-level page in the shadow chain and unwire it. A page 2370 * must exist at every page offset, and the highest-level page must be 2371 * wired. 2372 */ 2373 void 2374 vm_object_unwire(vm_object_t object, vm_ooffset_t offset, vm_size_t length, 2375 uint8_t queue) 2376 { 2377 vm_object_t tobject, t1object; 2378 vm_page_t m, tm; 2379 vm_pindex_t end_pindex, pindex, tpindex; 2380 int depth, locked_depth; 2381 2382 KASSERT((offset & PAGE_MASK) == 0, 2383 ("vm_object_unwire: offset is not page aligned")); 2384 KASSERT((length & PAGE_MASK) == 0, 2385 ("vm_object_unwire: length is not a multiple of PAGE_SIZE")); 2386 /* The wired count of a fictitious page never changes. */ 2387 if ((object->flags & OBJ_FICTITIOUS) != 0) 2388 return; 2389 pindex = OFF_TO_IDX(offset); 2390 end_pindex = pindex + atop(length); 2391 again: 2392 locked_depth = 1; 2393 VM_OBJECT_RLOCK(object); 2394 m = vm_page_find_least(object, pindex); 2395 while (pindex < end_pindex) { 2396 if (m == NULL || pindex < m->pindex) { 2397 /* 2398 * The first object in the shadow chain doesn't 2399 * contain a page at the current index. Therefore, 2400 * the page must exist in a backing object. 2401 */ 2402 tobject = object; 2403 tpindex = pindex; 2404 depth = 0; 2405 do { 2406 tpindex += 2407 OFF_TO_IDX(tobject->backing_object_offset); 2408 tobject = tobject->backing_object; 2409 KASSERT(tobject != NULL, 2410 ("vm_object_unwire: missing page")); 2411 if ((tobject->flags & OBJ_FICTITIOUS) != 0) 2412 goto next_page; 2413 depth++; 2414 if (depth == locked_depth) { 2415 locked_depth++; 2416 VM_OBJECT_RLOCK(tobject); 2417 } 2418 } while ((tm = vm_page_lookup(tobject, tpindex)) == 2419 NULL); 2420 } else { 2421 tm = m; 2422 m = TAILQ_NEXT(m, listq); 2423 } 2424 if (vm_page_trysbusy(tm) == 0) { 2425 for (tobject = object; locked_depth >= 1; 2426 locked_depth--) { 2427 t1object = tobject->backing_object; 2428 if (tm->object != tobject) 2429 VM_OBJECT_RUNLOCK(tobject); 2430 tobject = t1object; 2431 } 2432 tobject = tm->object; 2433 if (!vm_page_busy_sleep(tm, "unwbo", 2434 VM_ALLOC_IGN_SBUSY)) 2435 VM_OBJECT_RUNLOCK(tobject); 2436 goto again; 2437 } 2438 vm_page_unwire(tm, queue); 2439 vm_page_sunbusy(tm); 2440 next_page: 2441 pindex++; 2442 } 2443 /* Release the accumulated object locks. */ 2444 for (tobject = object; locked_depth >= 1; locked_depth--) { 2445 t1object = tobject->backing_object; 2446 VM_OBJECT_RUNLOCK(tobject); 2447 tobject = t1object; 2448 } 2449 } 2450 2451 /* 2452 * Return the vnode for the given object, or NULL if none exists. 2453 * For tmpfs objects, the function may return NULL if there is 2454 * no vnode allocated at the time of the call. 2455 */ 2456 struct vnode * 2457 vm_object_vnode(vm_object_t object) 2458 { 2459 struct vnode *vp; 2460 2461 VM_OBJECT_ASSERT_LOCKED(object); 2462 vm_pager_getvp(object, &vp, NULL); 2463 return (vp); 2464 } 2465 2466 /* 2467 * Busy the vm object. This prevents new pages belonging to the object from 2468 * becoming busy. Existing pages persist as busy. Callers are responsible 2469 * for checking page state before proceeding. 2470 */ 2471 void 2472 vm_object_busy(vm_object_t obj) 2473 { 2474 2475 VM_OBJECT_ASSERT_LOCKED(obj); 2476 2477 blockcount_acquire(&obj->busy, 1); 2478 /* The fence is required to order loads of page busy. */ 2479 atomic_thread_fence_acq_rel(); 2480 } 2481 2482 void 2483 vm_object_unbusy(vm_object_t obj) 2484 { 2485 2486 blockcount_release(&obj->busy, 1); 2487 } 2488 2489 void 2490 vm_object_busy_wait(vm_object_t obj, const char *wmesg) 2491 { 2492 2493 VM_OBJECT_ASSERT_UNLOCKED(obj); 2494 2495 (void)blockcount_sleep(&obj->busy, NULL, wmesg, PVM); 2496 } 2497 2498 /* 2499 * This function aims to determine if the object is mapped, 2500 * specifically, if it is referenced by a vm_map_entry. Because 2501 * objects occasionally acquire transient references that do not 2502 * represent a mapping, the method used here is inexact. However, it 2503 * has very low overhead and is good enough for the advisory 2504 * vm.vmtotal sysctl. 2505 */ 2506 bool 2507 vm_object_is_active(vm_object_t obj) 2508 { 2509 2510 return (obj->ref_count > atomic_load_int(&obj->shadow_count)); 2511 } 2512 2513 static int 2514 vm_object_list_handler(struct sysctl_req *req, bool swap_only) 2515 { 2516 struct kinfo_vmobject *kvo; 2517 char *fullpath, *freepath; 2518 struct vnode *vp; 2519 struct vattr va; 2520 vm_object_t obj; 2521 vm_page_t m; 2522 u_long sp; 2523 int count, error; 2524 2525 if (req->oldptr == NULL) { 2526 /* 2527 * If an old buffer has not been provided, generate an 2528 * estimate of the space needed for a subsequent call. 2529 */ 2530 mtx_lock(&vm_object_list_mtx); 2531 count = 0; 2532 TAILQ_FOREACH(obj, &vm_object_list, object_list) { 2533 if (obj->type == OBJT_DEAD) 2534 continue; 2535 count++; 2536 } 2537 mtx_unlock(&vm_object_list_mtx); 2538 return (SYSCTL_OUT(req, NULL, sizeof(struct kinfo_vmobject) * 2539 count * 11 / 10)); 2540 } 2541 2542 kvo = malloc(sizeof(*kvo), M_TEMP, M_WAITOK | M_ZERO); 2543 error = 0; 2544 2545 /* 2546 * VM objects are type stable and are never removed from the 2547 * list once added. This allows us to safely read obj->object_list 2548 * after reacquiring the VM object lock. 2549 */ 2550 mtx_lock(&vm_object_list_mtx); 2551 TAILQ_FOREACH(obj, &vm_object_list, object_list) { 2552 if (obj->type == OBJT_DEAD || 2553 (swap_only && (obj->flags & (OBJ_ANON | OBJ_SWAP)) == 0)) 2554 continue; 2555 VM_OBJECT_RLOCK(obj); 2556 if (obj->type == OBJT_DEAD || 2557 (swap_only && (obj->flags & (OBJ_ANON | OBJ_SWAP)) == 0)) { 2558 VM_OBJECT_RUNLOCK(obj); 2559 continue; 2560 } 2561 mtx_unlock(&vm_object_list_mtx); 2562 kvo->kvo_size = ptoa(obj->size); 2563 kvo->kvo_resident = obj->resident_page_count; 2564 kvo->kvo_ref_count = obj->ref_count; 2565 kvo->kvo_shadow_count = atomic_load_int(&obj->shadow_count); 2566 kvo->kvo_memattr = obj->memattr; 2567 kvo->kvo_active = 0; 2568 kvo->kvo_inactive = 0; 2569 if (!swap_only) { 2570 TAILQ_FOREACH(m, &obj->memq, listq) { 2571 /* 2572 * A page may belong to the object but be 2573 * dequeued and set to PQ_NONE while the 2574 * object lock is not held. This makes the 2575 * reads of m->queue below racy, and we do not 2576 * count pages set to PQ_NONE. However, this 2577 * sysctl is only meant to give an 2578 * approximation of the system anyway. 2579 */ 2580 if (m->a.queue == PQ_ACTIVE) 2581 kvo->kvo_active++; 2582 else if (m->a.queue == PQ_INACTIVE) 2583 kvo->kvo_inactive++; 2584 } 2585 } 2586 2587 kvo->kvo_vn_fileid = 0; 2588 kvo->kvo_vn_fsid = 0; 2589 kvo->kvo_vn_fsid_freebsd11 = 0; 2590 freepath = NULL; 2591 fullpath = ""; 2592 vp = NULL; 2593 kvo->kvo_type = vm_object_kvme_type(obj, swap_only ? NULL : &vp); 2594 if (vp != NULL) { 2595 vref(vp); 2596 } else if ((obj->flags & OBJ_ANON) != 0) { 2597 MPASS(kvo->kvo_type == KVME_TYPE_SWAP); 2598 kvo->kvo_me = (uintptr_t)obj; 2599 /* tmpfs objs are reported as vnodes */ 2600 kvo->kvo_backing_obj = (uintptr_t)obj->backing_object; 2601 sp = swap_pager_swapped_pages(obj); 2602 kvo->kvo_swapped = sp > UINT32_MAX ? UINT32_MAX : sp; 2603 } 2604 VM_OBJECT_RUNLOCK(obj); 2605 if (vp != NULL) { 2606 vn_fullpath(vp, &fullpath, &freepath); 2607 vn_lock(vp, LK_SHARED | LK_RETRY); 2608 if (VOP_GETATTR(vp, &va, curthread->td_ucred) == 0) { 2609 kvo->kvo_vn_fileid = va.va_fileid; 2610 kvo->kvo_vn_fsid = va.va_fsid; 2611 kvo->kvo_vn_fsid_freebsd11 = va.va_fsid; 2612 /* truncate */ 2613 } 2614 vput(vp); 2615 } 2616 2617 strlcpy(kvo->kvo_path, fullpath, sizeof(kvo->kvo_path)); 2618 if (freepath != NULL) 2619 free(freepath, M_TEMP); 2620 2621 /* Pack record size down */ 2622 kvo->kvo_structsize = offsetof(struct kinfo_vmobject, kvo_path) 2623 + strlen(kvo->kvo_path) + 1; 2624 kvo->kvo_structsize = roundup(kvo->kvo_structsize, 2625 sizeof(uint64_t)); 2626 error = SYSCTL_OUT(req, kvo, kvo->kvo_structsize); 2627 maybe_yield(); 2628 mtx_lock(&vm_object_list_mtx); 2629 if (error) 2630 break; 2631 } 2632 mtx_unlock(&vm_object_list_mtx); 2633 free(kvo, M_TEMP); 2634 return (error); 2635 } 2636 2637 static int 2638 sysctl_vm_object_list(SYSCTL_HANDLER_ARGS) 2639 { 2640 return (vm_object_list_handler(req, false)); 2641 } 2642 2643 SYSCTL_PROC(_vm, OID_AUTO, objects, CTLTYPE_STRUCT | CTLFLAG_RW | CTLFLAG_SKIP | 2644 CTLFLAG_MPSAFE, NULL, 0, sysctl_vm_object_list, "S,kinfo_vmobject", 2645 "List of VM objects"); 2646 2647 static int 2648 sysctl_vm_object_list_swap(SYSCTL_HANDLER_ARGS) 2649 { 2650 return (vm_object_list_handler(req, true)); 2651 } 2652 2653 /* 2654 * This sysctl returns list of the anonymous or swap objects. Intent 2655 * is to provide stripped optimized list useful to analyze swap use. 2656 * Since technically non-swap (default) objects participate in the 2657 * shadow chains, and are converted to swap type as needed by swap 2658 * pager, we must report them. 2659 */ 2660 SYSCTL_PROC(_vm, OID_AUTO, swap_objects, 2661 CTLTYPE_STRUCT | CTLFLAG_RW | CTLFLAG_SKIP | CTLFLAG_MPSAFE, NULL, 0, 2662 sysctl_vm_object_list_swap, "S,kinfo_vmobject", 2663 "List of swap VM objects"); 2664 2665 #include "opt_ddb.h" 2666 #ifdef DDB 2667 #include <sys/kernel.h> 2668 2669 #include <sys/cons.h> 2670 2671 #include <ddb/ddb.h> 2672 2673 static int 2674 _vm_object_in_map(vm_map_t map, vm_object_t object, vm_map_entry_t entry) 2675 { 2676 vm_map_t tmpm; 2677 vm_map_entry_t tmpe; 2678 vm_object_t obj; 2679 2680 if (map == 0) 2681 return 0; 2682 2683 if (entry == 0) { 2684 VM_MAP_ENTRY_FOREACH(tmpe, map) { 2685 if (_vm_object_in_map(map, object, tmpe)) { 2686 return 1; 2687 } 2688 } 2689 } else if (entry->eflags & MAP_ENTRY_IS_SUB_MAP) { 2690 tmpm = entry->object.sub_map; 2691 VM_MAP_ENTRY_FOREACH(tmpe, tmpm) { 2692 if (_vm_object_in_map(tmpm, object, tmpe)) { 2693 return 1; 2694 } 2695 } 2696 } else if ((obj = entry->object.vm_object) != NULL) { 2697 for (; obj; obj = obj->backing_object) 2698 if (obj == object) { 2699 return 1; 2700 } 2701 } 2702 return 0; 2703 } 2704 2705 static int 2706 vm_object_in_map(vm_object_t object) 2707 { 2708 struct proc *p; 2709 2710 /* sx_slock(&allproc_lock); */ 2711 FOREACH_PROC_IN_SYSTEM(p) { 2712 if (!p->p_vmspace /* || (p->p_flag & (P_SYSTEM|P_WEXIT)) */) 2713 continue; 2714 if (_vm_object_in_map(&p->p_vmspace->vm_map, object, 0)) { 2715 /* sx_sunlock(&allproc_lock); */ 2716 return 1; 2717 } 2718 } 2719 /* sx_sunlock(&allproc_lock); */ 2720 if (_vm_object_in_map(kernel_map, object, 0)) 2721 return 1; 2722 return 0; 2723 } 2724 2725 DB_SHOW_COMMAND_FLAGS(vmochk, vm_object_check, DB_CMD_MEMSAFE) 2726 { 2727 vm_object_t object; 2728 2729 /* 2730 * make sure that internal objs are in a map somewhere 2731 * and none have zero ref counts. 2732 */ 2733 TAILQ_FOREACH(object, &vm_object_list, object_list) { 2734 if ((object->flags & OBJ_ANON) != 0) { 2735 if (object->ref_count == 0) { 2736 db_printf("vmochk: internal obj has zero ref count: %ld\n", 2737 (long)object->size); 2738 } 2739 if (!vm_object_in_map(object)) { 2740 db_printf( 2741 "vmochk: internal obj is not in a map: " 2742 "ref: %d, size: %lu: 0x%lx, backing_object: %p\n", 2743 object->ref_count, (u_long)object->size, 2744 (u_long)object->size, 2745 (void *)object->backing_object); 2746 } 2747 } 2748 if (db_pager_quit) 2749 return; 2750 } 2751 } 2752 2753 /* 2754 * vm_object_print: [ debug ] 2755 */ 2756 DB_SHOW_COMMAND(object, vm_object_print_static) 2757 { 2758 /* XXX convert args. */ 2759 vm_object_t object = (vm_object_t)addr; 2760 boolean_t full = have_addr; 2761 2762 vm_page_t p; 2763 2764 /* XXX count is an (unused) arg. Avoid shadowing it. */ 2765 #define count was_count 2766 2767 int count; 2768 2769 if (object == NULL) 2770 return; 2771 2772 db_iprintf( 2773 "Object %p: type=%d, size=0x%jx, res=%d, ref=%d, flags=0x%x ruid %d charge %jx\n", 2774 object, (int)object->type, (uintmax_t)object->size, 2775 object->resident_page_count, object->ref_count, object->flags, 2776 object->cred ? object->cred->cr_ruid : -1, (uintmax_t)object->charge); 2777 db_iprintf(" sref=%d, backing_object(%d)=(%p)+0x%jx\n", 2778 atomic_load_int(&object->shadow_count), 2779 object->backing_object ? object->backing_object->ref_count : 0, 2780 object->backing_object, (uintmax_t)object->backing_object_offset); 2781 2782 if (!full) 2783 return; 2784 2785 db_indent += 2; 2786 count = 0; 2787 TAILQ_FOREACH(p, &object->memq, listq) { 2788 if (count == 0) 2789 db_iprintf("memory:="); 2790 else if (count == 6) { 2791 db_printf("\n"); 2792 db_iprintf(" ..."); 2793 count = 0; 2794 } else 2795 db_printf(","); 2796 count++; 2797 2798 db_printf("(off=0x%jx,page=0x%jx)", 2799 (uintmax_t)p->pindex, (uintmax_t)VM_PAGE_TO_PHYS(p)); 2800 2801 if (db_pager_quit) 2802 break; 2803 } 2804 if (count != 0) 2805 db_printf("\n"); 2806 db_indent -= 2; 2807 } 2808 2809 /* XXX. */ 2810 #undef count 2811 2812 /* XXX need this non-static entry for calling from vm_map_print. */ 2813 void 2814 vm_object_print( 2815 /* db_expr_t */ long addr, 2816 boolean_t have_addr, 2817 /* db_expr_t */ long count, 2818 char *modif) 2819 { 2820 vm_object_print_static(addr, have_addr, count, modif); 2821 } 2822 2823 DB_SHOW_COMMAND_FLAGS(vmopag, vm_object_print_pages, DB_CMD_MEMSAFE) 2824 { 2825 vm_object_t object; 2826 vm_pindex_t fidx; 2827 vm_paddr_t pa; 2828 vm_page_t m, prev_m; 2829 int rcount; 2830 2831 TAILQ_FOREACH(object, &vm_object_list, object_list) { 2832 db_printf("new object: %p\n", (void *)object); 2833 if (db_pager_quit) 2834 return; 2835 2836 rcount = 0; 2837 fidx = 0; 2838 pa = -1; 2839 TAILQ_FOREACH(m, &object->memq, listq) { 2840 if ((prev_m = TAILQ_PREV(m, pglist, listq)) != NULL && 2841 prev_m->pindex + 1 != m->pindex) { 2842 if (rcount) { 2843 db_printf(" index(%ld)run(%d)pa(0x%lx)\n", 2844 (long)fidx, rcount, (long)pa); 2845 if (db_pager_quit) 2846 return; 2847 rcount = 0; 2848 } 2849 } 2850 if (rcount && 2851 (VM_PAGE_TO_PHYS(m) == pa + rcount * PAGE_SIZE)) { 2852 ++rcount; 2853 continue; 2854 } 2855 if (rcount) { 2856 db_printf(" index(%ld)run(%d)pa(0x%lx)\n", 2857 (long)fidx, rcount, (long)pa); 2858 if (db_pager_quit) 2859 return; 2860 } 2861 fidx = m->pindex; 2862 pa = VM_PAGE_TO_PHYS(m); 2863 rcount = 1; 2864 } 2865 if (rcount) { 2866 db_printf(" index(%ld)run(%d)pa(0x%lx)\n", 2867 (long)fidx, rcount, (long)pa); 2868 if (db_pager_quit) 2869 return; 2870 } 2871 } 2872 } 2873 #endif /* DDB */ 2874