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 * 35 * Copyright (c) 1987, 1990 Carnegie-Mellon University. 36 * All rights reserved. 37 * 38 * Authors: Avadis Tevanian, Jr., Michael Wayne Young 39 * 40 * Permission to use, copy, modify and distribute this software and 41 * its documentation is hereby granted, provided that both the copyright 42 * notice and this permission notice appear in all copies of the 43 * software, derivative works or modified versions, and any portions 44 * thereof, and that both notices appear in supporting documentation. 45 * 46 * CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS" 47 * CONDITION. CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND 48 * FOR ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE. 49 * 50 * Carnegie Mellon requests users of this software to return to 51 * 52 * Software Distribution Coordinator or Software.Distribution@CS.CMU.EDU 53 * School of Computer Science 54 * Carnegie Mellon University 55 * Pittsburgh PA 15213-3890 56 * 57 * any improvements or extensions that they make and grant Carnegie the 58 * rights to redistribute these changes. 59 */ 60 61 /* 62 * Virtual memory object module. 63 */ 64 65 #include <sys/cdefs.h> 66 #include "opt_vm.h" 67 68 #include <sys/param.h> 69 #include <sys/systm.h> 70 #include <sys/blockcount.h> 71 #include <sys/cpuset.h> 72 #include <sys/limits.h> 73 #include <sys/lock.h> 74 #include <sys/mman.h> 75 #include <sys/mount.h> 76 #include <sys/kernel.h> 77 #include <sys/pctrie.h> 78 #include <sys/sysctl.h> 79 #include <sys/mutex.h> 80 #include <sys/proc.h> /* for curproc, pageproc */ 81 #include <sys/refcount.h> 82 #include <sys/socket.h> 83 #include <sys/resourcevar.h> 84 #include <sys/refcount.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 *allclean, 114 boolean_t *eio); 115 static boolean_t vm_object_page_remove_write(vm_page_t p, int flags, 116 boolean_t *allclean); 117 static void vm_object_backing_remove(vm_object_t object); 118 119 /* 120 * Virtual memory objects maintain the actual data 121 * associated with allocated virtual memory. A given 122 * page of memory exists within exactly one object. 123 * 124 * An object is only deallocated when all "references" 125 * are given up. Only one "reference" to a given 126 * region of an object should be writeable. 127 * 128 * Associated with each object is a list of all resident 129 * memory pages belonging to that object; this list is 130 * maintained by the "vm_page" module, and locked by the object's 131 * lock. 132 * 133 * Each object also records a "pager" routine which is 134 * used to retrieve (and store) pages to the proper backing 135 * storage. In addition, objects may be backed by other 136 * objects from which they were virtual-copied. 137 * 138 * The only items within the object structure which are 139 * modified after time of creation are: 140 * reference count locked by object's lock 141 * pager routine locked by object's lock 142 * 143 */ 144 145 struct object_q vm_object_list; 146 struct mtx vm_object_list_mtx; /* lock for object list and count */ 147 148 struct vm_object kernel_object_store; 149 150 static SYSCTL_NODE(_vm_stats, OID_AUTO, object, CTLFLAG_RD | CTLFLAG_MPSAFE, 0, 151 "VM object stats"); 152 153 static COUNTER_U64_DEFINE_EARLY(object_collapses); 154 SYSCTL_COUNTER_U64(_vm_stats_object, OID_AUTO, collapses, CTLFLAG_RD, 155 &object_collapses, 156 "VM object collapses"); 157 158 static COUNTER_U64_DEFINE_EARLY(object_bypasses); 159 SYSCTL_COUNTER_U64(_vm_stats_object, OID_AUTO, bypasses, CTLFLAG_RD, 160 &object_bypasses, 161 "VM object bypasses"); 162 163 static COUNTER_U64_DEFINE_EARLY(object_collapse_waits); 164 SYSCTL_COUNTER_U64(_vm_stats_object, OID_AUTO, collapse_waits, CTLFLAG_RD, 165 &object_collapse_waits, 166 "Number of sleeps for collapse"); 167 168 static uma_zone_t obj_zone; 169 170 static int vm_object_zinit(void *mem, int size, int flags); 171 172 #ifdef INVARIANTS 173 static void vm_object_zdtor(void *mem, int size, void *arg); 174 175 static void 176 vm_object_zdtor(void *mem, int size, void *arg) 177 { 178 vm_object_t object; 179 180 object = (vm_object_t)mem; 181 KASSERT(object->ref_count == 0, 182 ("object %p ref_count = %d", object, object->ref_count)); 183 KASSERT(TAILQ_EMPTY(&object->memq), 184 ("object %p has resident pages in its memq", object)); 185 KASSERT(vm_radix_is_empty(&object->rtree), 186 ("object %p has resident pages in its trie", object)); 187 #if VM_NRESERVLEVEL > 0 188 KASSERT(LIST_EMPTY(&object->rvq), 189 ("object %p has reservations", 190 object)); 191 #endif 192 KASSERT(!vm_object_busied(object), 193 ("object %p busy = %d", object, blockcount_read(&object->busy))); 194 KASSERT(object->resident_page_count == 0, 195 ("object %p resident_page_count = %d", 196 object, object->resident_page_count)); 197 KASSERT(atomic_load_int(&object->shadow_count) == 0, 198 ("object %p shadow_count = %d", 199 object, atomic_load_int(&object->shadow_count))); 200 KASSERT(object->type == OBJT_DEAD, 201 ("object %p has non-dead type %d", 202 object, object->type)); 203 KASSERT(object->charge == 0 && object->cred == NULL, 204 ("object %p has non-zero charge %ju (%p)", 205 object, (uintmax_t)object->charge, object->cred)); 206 } 207 #endif 208 209 static int 210 vm_object_zinit(void *mem, int size, int flags) 211 { 212 vm_object_t object; 213 214 object = (vm_object_t)mem; 215 rw_init_flags(&object->lock, "vmobject", RW_DUPOK | RW_NEW); 216 217 /* These are true for any object that has been freed */ 218 object->type = OBJT_DEAD; 219 vm_radix_init(&object->rtree); 220 refcount_init(&object->ref_count, 0); 221 blockcount_init(&object->paging_in_progress); 222 blockcount_init(&object->busy); 223 object->resident_page_count = 0; 224 atomic_store_int(&object->shadow_count, 0); 225 object->flags = OBJ_DEAD; 226 227 mtx_lock(&vm_object_list_mtx); 228 TAILQ_INSERT_TAIL(&vm_object_list, object, object_list); 229 mtx_unlock(&vm_object_list_mtx); 230 return (0); 231 } 232 233 static void 234 _vm_object_allocate(objtype_t type, vm_pindex_t size, u_short flags, 235 vm_object_t object, void *handle) 236 { 237 238 TAILQ_INIT(&object->memq); 239 LIST_INIT(&object->shadow_head); 240 241 object->type = type; 242 object->flags = flags; 243 if ((flags & OBJ_SWAP) != 0) { 244 pctrie_init(&object->un_pager.swp.swp_blks); 245 object->un_pager.swp.writemappings = 0; 246 } 247 248 /* 249 * Ensure that swap_pager_swapoff() iteration over object_list 250 * sees up to date type and pctrie head if it observed 251 * non-dead object. 252 */ 253 atomic_thread_fence_rel(); 254 255 object->pg_color = 0; 256 object->size = size; 257 object->domain.dr_policy = NULL; 258 object->generation = 1; 259 object->cleangeneration = 1; 260 refcount_init(&object->ref_count, 1); 261 object->memattr = VM_MEMATTR_DEFAULT; 262 object->cred = NULL; 263 object->charge = 0; 264 object->handle = handle; 265 object->backing_object = NULL; 266 object->backing_object_offset = (vm_ooffset_t) 0; 267 #if VM_NRESERVLEVEL > 0 268 LIST_INIT(&object->rvq); 269 #endif 270 umtx_shm_object_init(object); 271 } 272 273 /* 274 * vm_object_init: 275 * 276 * Initialize the VM objects module. 277 */ 278 void 279 vm_object_init(void) 280 { 281 TAILQ_INIT(&vm_object_list); 282 mtx_init(&vm_object_list_mtx, "vm object_list", NULL, MTX_DEF); 283 284 rw_init(&kernel_object->lock, "kernel vm object"); 285 vm_radix_init(&kernel_object->rtree); 286 _vm_object_allocate(OBJT_PHYS, atop(VM_MAX_KERNEL_ADDRESS - 287 VM_MIN_KERNEL_ADDRESS), OBJ_UNMANAGED, kernel_object, NULL); 288 #if VM_NRESERVLEVEL > 0 289 kernel_object->flags |= OBJ_COLORED; 290 kernel_object->pg_color = (u_short)atop(VM_MIN_KERNEL_ADDRESS); 291 #endif 292 kernel_object->un_pager.phys.ops = &default_phys_pg_ops; 293 294 /* 295 * The lock portion of struct vm_object must be type stable due 296 * to vm_pageout_fallback_object_lock locking a vm object 297 * without holding any references to it. 298 * 299 * paging_in_progress is valid always. Lockless references to 300 * the objects may acquire pip and then check OBJ_DEAD. 301 */ 302 obj_zone = uma_zcreate("VM OBJECT", sizeof (struct vm_object), NULL, 303 #ifdef INVARIANTS 304 vm_object_zdtor, 305 #else 306 NULL, 307 #endif 308 vm_object_zinit, NULL, UMA_ALIGN_PTR, UMA_ZONE_NOFREE); 309 310 vm_radix_zinit(); 311 } 312 313 void 314 vm_object_clear_flag(vm_object_t object, u_short bits) 315 { 316 317 VM_OBJECT_ASSERT_WLOCKED(object); 318 object->flags &= ~bits; 319 } 320 321 /* 322 * Sets the default memory attribute for the specified object. Pages 323 * that are allocated to this object are by default assigned this memory 324 * attribute. 325 * 326 * Presently, this function must be called before any pages are allocated 327 * to the object. In the future, this requirement may be relaxed for 328 * "default" and "swap" objects. 329 */ 330 int 331 vm_object_set_memattr(vm_object_t object, vm_memattr_t memattr) 332 { 333 334 VM_OBJECT_ASSERT_WLOCKED(object); 335 336 if (object->type == OBJT_DEAD) 337 return (KERN_INVALID_ARGUMENT); 338 if (!TAILQ_EMPTY(&object->memq)) 339 return (KERN_FAILURE); 340 341 object->memattr = memattr; 342 return (KERN_SUCCESS); 343 } 344 345 void 346 vm_object_pip_add(vm_object_t object, short i) 347 { 348 349 if (i > 0) 350 blockcount_acquire(&object->paging_in_progress, i); 351 } 352 353 void 354 vm_object_pip_wakeup(vm_object_t object) 355 { 356 357 vm_object_pip_wakeupn(object, 1); 358 } 359 360 void 361 vm_object_pip_wakeupn(vm_object_t object, short i) 362 { 363 364 if (i > 0) 365 blockcount_release(&object->paging_in_progress, i); 366 } 367 368 /* 369 * Atomically drop the object lock and wait for pip to drain. This protects 370 * from sleep/wakeup races due to identity changes. The lock is not re-acquired 371 * on return. 372 */ 373 static void 374 vm_object_pip_sleep(vm_object_t object, const char *waitid) 375 { 376 377 (void)blockcount_sleep(&object->paging_in_progress, &object->lock, 378 waitid, PVM | PDROP); 379 } 380 381 void 382 vm_object_pip_wait(vm_object_t object, const char *waitid) 383 { 384 385 VM_OBJECT_ASSERT_WLOCKED(object); 386 387 blockcount_wait(&object->paging_in_progress, &object->lock, waitid, 388 PVM); 389 } 390 391 void 392 vm_object_pip_wait_unlocked(vm_object_t object, const char *waitid) 393 { 394 395 VM_OBJECT_ASSERT_UNLOCKED(object); 396 397 blockcount_wait(&object->paging_in_progress, NULL, waitid, PVM); 398 } 399 400 /* 401 * vm_object_allocate: 402 * 403 * Returns a new object with the given size. 404 */ 405 vm_object_t 406 vm_object_allocate(objtype_t type, vm_pindex_t size) 407 { 408 vm_object_t object; 409 u_short flags; 410 411 switch (type) { 412 case OBJT_DEAD: 413 panic("vm_object_allocate: can't create OBJT_DEAD"); 414 case OBJT_SWAP: 415 flags = OBJ_COLORED | OBJ_SWAP; 416 break; 417 case OBJT_DEVICE: 418 case OBJT_SG: 419 flags = OBJ_FICTITIOUS | OBJ_UNMANAGED; 420 break; 421 case OBJT_MGTDEVICE: 422 flags = OBJ_FICTITIOUS; 423 break; 424 case OBJT_PHYS: 425 flags = OBJ_UNMANAGED; 426 break; 427 case OBJT_VNODE: 428 flags = 0; 429 break; 430 default: 431 panic("vm_object_allocate: type %d is undefined or dynamic", 432 type); 433 } 434 object = (vm_object_t)uma_zalloc(obj_zone, M_WAITOK); 435 _vm_object_allocate(type, size, flags, object, NULL); 436 437 return (object); 438 } 439 440 vm_object_t 441 vm_object_allocate_dyn(objtype_t dyntype, vm_pindex_t size, u_short flags) 442 { 443 vm_object_t object; 444 445 MPASS(dyntype >= OBJT_FIRST_DYN /* && dyntype < nitems(pagertab) */); 446 object = (vm_object_t)uma_zalloc(obj_zone, M_WAITOK); 447 _vm_object_allocate(dyntype, size, flags, object, NULL); 448 449 return (object); 450 } 451 452 /* 453 * vm_object_allocate_anon: 454 * 455 * Returns a new default object of the given size and marked as 456 * anonymous memory for special split/collapse handling. Color 457 * to be initialized by the caller. 458 */ 459 vm_object_t 460 vm_object_allocate_anon(vm_pindex_t size, vm_object_t backing_object, 461 struct ucred *cred, vm_size_t charge) 462 { 463 vm_object_t handle, object; 464 465 if (backing_object == NULL) 466 handle = NULL; 467 else if ((backing_object->flags & OBJ_ANON) != 0) 468 handle = backing_object->handle; 469 else 470 handle = backing_object; 471 object = uma_zalloc(obj_zone, M_WAITOK); 472 _vm_object_allocate(OBJT_SWAP, size, 473 OBJ_ANON | OBJ_ONEMAPPING | OBJ_SWAP, object, handle); 474 object->cred = cred; 475 object->charge = cred != NULL ? charge : 0; 476 return (object); 477 } 478 479 static void 480 vm_object_reference_vnode(vm_object_t object) 481 { 482 u_int old; 483 484 /* 485 * vnode objects need the lock for the first reference 486 * to serialize with vnode_object_deallocate(). 487 */ 488 if (!refcount_acquire_if_gt(&object->ref_count, 0)) { 489 VM_OBJECT_RLOCK(object); 490 old = refcount_acquire(&object->ref_count); 491 if (object->type == OBJT_VNODE && old == 0) 492 vref(object->handle); 493 VM_OBJECT_RUNLOCK(object); 494 } 495 } 496 497 /* 498 * vm_object_reference: 499 * 500 * Acquires a reference to the given object. 501 */ 502 void 503 vm_object_reference(vm_object_t object) 504 { 505 506 if (object == NULL) 507 return; 508 509 if (object->type == OBJT_VNODE) 510 vm_object_reference_vnode(object); 511 else 512 refcount_acquire(&object->ref_count); 513 KASSERT((object->flags & OBJ_DEAD) == 0, 514 ("vm_object_reference: Referenced dead object.")); 515 } 516 517 /* 518 * vm_object_reference_locked: 519 * 520 * Gets another reference to the given object. 521 * 522 * The object must be locked. 523 */ 524 void 525 vm_object_reference_locked(vm_object_t object) 526 { 527 u_int old; 528 529 VM_OBJECT_ASSERT_LOCKED(object); 530 old = refcount_acquire(&object->ref_count); 531 if (object->type == OBJT_VNODE && old == 0) 532 vref(object->handle); 533 KASSERT((object->flags & OBJ_DEAD) == 0, 534 ("vm_object_reference: Referenced dead object.")); 535 } 536 537 /* 538 * Handle deallocating an object of type OBJT_VNODE. 539 */ 540 static void 541 vm_object_deallocate_vnode(vm_object_t object) 542 { 543 struct vnode *vp = (struct vnode *) object->handle; 544 bool last; 545 546 KASSERT(object->type == OBJT_VNODE, 547 ("vm_object_deallocate_vnode: not a vnode object")); 548 KASSERT(vp != NULL, ("vm_object_deallocate_vnode: missing vp")); 549 550 /* Object lock to protect handle lookup. */ 551 last = refcount_release(&object->ref_count); 552 VM_OBJECT_RUNLOCK(object); 553 554 if (!last) 555 return; 556 557 if (!umtx_shm_vnobj_persistent) 558 umtx_shm_object_terminated(object); 559 560 /* vrele may need the vnode lock. */ 561 vrele(vp); 562 } 563 564 /* 565 * We dropped a reference on an object and discovered that it had a 566 * single remaining shadow. This is a sibling of the reference we 567 * dropped. Attempt to collapse the sibling and backing object. 568 */ 569 static vm_object_t 570 vm_object_deallocate_anon(vm_object_t backing_object) 571 { 572 vm_object_t object; 573 574 /* Fetch the final shadow. */ 575 object = LIST_FIRST(&backing_object->shadow_head); 576 KASSERT(object != NULL && 577 atomic_load_int(&backing_object->shadow_count) == 1, 578 ("vm_object_anon_deallocate: ref_count: %d, shadow_count: %d", 579 backing_object->ref_count, 580 atomic_load_int(&backing_object->shadow_count))); 581 KASSERT((object->flags & OBJ_ANON) != 0, 582 ("invalid shadow object %p", object)); 583 584 if (!VM_OBJECT_TRYWLOCK(object)) { 585 /* 586 * Prevent object from disappearing since we do not have a 587 * reference. 588 */ 589 vm_object_pip_add(object, 1); 590 VM_OBJECT_WUNLOCK(backing_object); 591 VM_OBJECT_WLOCK(object); 592 vm_object_pip_wakeup(object); 593 } else 594 VM_OBJECT_WUNLOCK(backing_object); 595 596 /* 597 * Check for a collapse/terminate race with the last reference holder. 598 */ 599 if ((object->flags & (OBJ_DEAD | OBJ_COLLAPSING)) != 0 || 600 !refcount_acquire_if_not_zero(&object->ref_count)) { 601 VM_OBJECT_WUNLOCK(object); 602 return (NULL); 603 } 604 backing_object = object->backing_object; 605 if (backing_object != NULL && (backing_object->flags & OBJ_ANON) != 0) 606 vm_object_collapse(object); 607 VM_OBJECT_WUNLOCK(object); 608 609 return (object); 610 } 611 612 /* 613 * vm_object_deallocate: 614 * 615 * Release a reference to the specified object, 616 * gained either through a vm_object_allocate 617 * or a vm_object_reference call. When all references 618 * are gone, storage associated with this object 619 * may be relinquished. 620 * 621 * No object may be locked. 622 */ 623 void 624 vm_object_deallocate(vm_object_t object) 625 { 626 vm_object_t temp; 627 bool released; 628 629 while (object != NULL) { 630 /* 631 * If the reference count goes to 0 we start calling 632 * vm_object_terminate() on the object chain. A ref count 633 * of 1 may be a special case depending on the shadow count 634 * being 0 or 1. These cases require a write lock on the 635 * object. 636 */ 637 if ((object->flags & OBJ_ANON) == 0) 638 released = refcount_release_if_gt(&object->ref_count, 1); 639 else 640 released = refcount_release_if_gt(&object->ref_count, 2); 641 if (released) 642 return; 643 644 if (object->type == OBJT_VNODE) { 645 VM_OBJECT_RLOCK(object); 646 if (object->type == OBJT_VNODE) { 647 vm_object_deallocate_vnode(object); 648 return; 649 } 650 VM_OBJECT_RUNLOCK(object); 651 } 652 653 VM_OBJECT_WLOCK(object); 654 KASSERT(object->ref_count > 0, 655 ("vm_object_deallocate: object deallocated too many times: %d", 656 object->type)); 657 658 /* 659 * If this is not the final reference to an anonymous 660 * object we may need to collapse the shadow chain. 661 */ 662 if (!refcount_release(&object->ref_count)) { 663 if (object->ref_count > 1 || 664 atomic_load_int(&object->shadow_count) == 0) { 665 if ((object->flags & OBJ_ANON) != 0 && 666 object->ref_count == 1) 667 vm_object_set_flag(object, 668 OBJ_ONEMAPPING); 669 VM_OBJECT_WUNLOCK(object); 670 return; 671 } 672 673 /* Handle collapsing last ref on anonymous objects. */ 674 object = vm_object_deallocate_anon(object); 675 continue; 676 } 677 678 /* 679 * Handle the final reference to an object. We restart 680 * the loop with the backing object to avoid recursion. 681 */ 682 umtx_shm_object_terminated(object); 683 temp = object->backing_object; 684 if (temp != NULL) { 685 KASSERT(object->type == OBJT_SWAP, 686 ("shadowed tmpfs v_object 2 %p", object)); 687 vm_object_backing_remove(object); 688 } 689 690 KASSERT((object->flags & OBJ_DEAD) == 0, 691 ("vm_object_deallocate: Terminating dead object.")); 692 vm_object_set_flag(object, OBJ_DEAD); 693 vm_object_terminate(object); 694 object = temp; 695 } 696 } 697 698 void 699 vm_object_destroy(vm_object_t object) 700 { 701 uma_zfree(obj_zone, object); 702 } 703 704 static void 705 vm_object_sub_shadow(vm_object_t object) 706 { 707 KASSERT(object->shadow_count >= 1, 708 ("object %p sub_shadow count zero", object)); 709 atomic_subtract_int(&object->shadow_count, 1); 710 } 711 712 static void 713 vm_object_backing_remove_locked(vm_object_t object) 714 { 715 vm_object_t backing_object; 716 717 backing_object = object->backing_object; 718 VM_OBJECT_ASSERT_WLOCKED(object); 719 VM_OBJECT_ASSERT_WLOCKED(backing_object); 720 721 KASSERT((object->flags & OBJ_COLLAPSING) == 0, 722 ("vm_object_backing_remove: Removing collapsing object.")); 723 724 vm_object_sub_shadow(backing_object); 725 if ((object->flags & OBJ_SHADOWLIST) != 0) { 726 LIST_REMOVE(object, shadow_list); 727 vm_object_clear_flag(object, OBJ_SHADOWLIST); 728 } 729 object->backing_object = NULL; 730 } 731 732 static void 733 vm_object_backing_remove(vm_object_t object) 734 { 735 vm_object_t backing_object; 736 737 VM_OBJECT_ASSERT_WLOCKED(object); 738 739 backing_object = object->backing_object; 740 if ((object->flags & OBJ_SHADOWLIST) != 0) { 741 VM_OBJECT_WLOCK(backing_object); 742 vm_object_backing_remove_locked(object); 743 VM_OBJECT_WUNLOCK(backing_object); 744 } else { 745 object->backing_object = NULL; 746 vm_object_sub_shadow(backing_object); 747 } 748 } 749 750 static void 751 vm_object_backing_insert_locked(vm_object_t object, vm_object_t backing_object) 752 { 753 754 VM_OBJECT_ASSERT_WLOCKED(object); 755 756 atomic_add_int(&backing_object->shadow_count, 1); 757 if ((backing_object->flags & OBJ_ANON) != 0) { 758 VM_OBJECT_ASSERT_WLOCKED(backing_object); 759 LIST_INSERT_HEAD(&backing_object->shadow_head, object, 760 shadow_list); 761 vm_object_set_flag(object, OBJ_SHADOWLIST); 762 } 763 object->backing_object = backing_object; 764 } 765 766 static void 767 vm_object_backing_insert(vm_object_t object, vm_object_t backing_object) 768 { 769 770 VM_OBJECT_ASSERT_WLOCKED(object); 771 772 if ((backing_object->flags & OBJ_ANON) != 0) { 773 VM_OBJECT_WLOCK(backing_object); 774 vm_object_backing_insert_locked(object, backing_object); 775 VM_OBJECT_WUNLOCK(backing_object); 776 } else { 777 object->backing_object = backing_object; 778 atomic_add_int(&backing_object->shadow_count, 1); 779 } 780 } 781 782 /* 783 * Insert an object into a backing_object's shadow list with an additional 784 * reference to the backing_object added. 785 */ 786 static void 787 vm_object_backing_insert_ref(vm_object_t object, vm_object_t backing_object) 788 { 789 790 VM_OBJECT_ASSERT_WLOCKED(object); 791 792 if ((backing_object->flags & OBJ_ANON) != 0) { 793 VM_OBJECT_WLOCK(backing_object); 794 KASSERT((backing_object->flags & OBJ_DEAD) == 0, 795 ("shadowing dead anonymous object")); 796 vm_object_reference_locked(backing_object); 797 vm_object_backing_insert_locked(object, backing_object); 798 vm_object_clear_flag(backing_object, OBJ_ONEMAPPING); 799 VM_OBJECT_WUNLOCK(backing_object); 800 } else { 801 vm_object_reference(backing_object); 802 atomic_add_int(&backing_object->shadow_count, 1); 803 object->backing_object = backing_object; 804 } 805 } 806 807 /* 808 * Transfer a backing reference from backing_object to object. 809 */ 810 static void 811 vm_object_backing_transfer(vm_object_t object, vm_object_t backing_object) 812 { 813 vm_object_t new_backing_object; 814 815 /* 816 * Note that the reference to backing_object->backing_object 817 * moves from within backing_object to within object. 818 */ 819 vm_object_backing_remove_locked(object); 820 new_backing_object = backing_object->backing_object; 821 if (new_backing_object == NULL) 822 return; 823 if ((new_backing_object->flags & OBJ_ANON) != 0) { 824 VM_OBJECT_WLOCK(new_backing_object); 825 vm_object_backing_remove_locked(backing_object); 826 vm_object_backing_insert_locked(object, new_backing_object); 827 VM_OBJECT_WUNLOCK(new_backing_object); 828 } else { 829 /* 830 * shadow_count for new_backing_object is left 831 * unchanged, its reference provided by backing_object 832 * is replaced by object. 833 */ 834 object->backing_object = new_backing_object; 835 backing_object->backing_object = NULL; 836 } 837 } 838 839 /* 840 * Wait for a concurrent collapse to settle. 841 */ 842 static void 843 vm_object_collapse_wait(vm_object_t object) 844 { 845 846 VM_OBJECT_ASSERT_WLOCKED(object); 847 848 while ((object->flags & OBJ_COLLAPSING) != 0) { 849 vm_object_pip_wait(object, "vmcolwait"); 850 counter_u64_add(object_collapse_waits, 1); 851 } 852 } 853 854 /* 855 * Waits for a backing object to clear a pending collapse and returns 856 * it locked if it is an ANON object. 857 */ 858 static vm_object_t 859 vm_object_backing_collapse_wait(vm_object_t object) 860 { 861 vm_object_t backing_object; 862 863 VM_OBJECT_ASSERT_WLOCKED(object); 864 865 for (;;) { 866 backing_object = object->backing_object; 867 if (backing_object == NULL || 868 (backing_object->flags & OBJ_ANON) == 0) 869 return (NULL); 870 VM_OBJECT_WLOCK(backing_object); 871 if ((backing_object->flags & (OBJ_DEAD | OBJ_COLLAPSING)) == 0) 872 break; 873 VM_OBJECT_WUNLOCK(object); 874 vm_object_pip_sleep(backing_object, "vmbckwait"); 875 counter_u64_add(object_collapse_waits, 1); 876 VM_OBJECT_WLOCK(object); 877 } 878 return (backing_object); 879 } 880 881 /* 882 * vm_object_terminate_pages removes any remaining pageable pages 883 * from the object and resets the object to an empty state. 884 */ 885 static void 886 vm_object_terminate_pages(vm_object_t object) 887 { 888 vm_page_t p, p_next; 889 890 VM_OBJECT_ASSERT_WLOCKED(object); 891 892 /* 893 * Free any remaining pageable pages. This also removes them from the 894 * paging queues. However, don't free wired pages, just remove them 895 * from the object. Rather than incrementally removing each page from 896 * the object, the page and object are reset to any empty state. 897 */ 898 TAILQ_FOREACH_SAFE(p, &object->memq, listq, p_next) { 899 vm_page_assert_unbusied(p); 900 KASSERT(p->object == object && 901 (p->ref_count & VPRC_OBJREF) != 0, 902 ("vm_object_terminate_pages: page %p is inconsistent", p)); 903 904 p->object = NULL; 905 if (vm_page_drop(p, VPRC_OBJREF) == VPRC_OBJREF) { 906 VM_CNT_INC(v_pfree); 907 vm_page_free(p); 908 } 909 } 910 911 /* 912 * If the object contained any pages, then reset it to an empty state. 913 * None of the object's fields, including "resident_page_count", were 914 * modified by the preceding loop. 915 */ 916 if (object->resident_page_count != 0) { 917 vm_radix_reclaim_allnodes(&object->rtree); 918 TAILQ_INIT(&object->memq); 919 object->resident_page_count = 0; 920 if (object->type == OBJT_VNODE) 921 vdrop(object->handle); 922 } 923 } 924 925 /* 926 * vm_object_terminate actually destroys the specified object, freeing 927 * up all previously used resources. 928 * 929 * The object must be locked. 930 * This routine may block. 931 */ 932 void 933 vm_object_terminate(vm_object_t object) 934 { 935 936 VM_OBJECT_ASSERT_WLOCKED(object); 937 KASSERT((object->flags & OBJ_DEAD) != 0, 938 ("terminating non-dead obj %p", object)); 939 KASSERT((object->flags & OBJ_COLLAPSING) == 0, 940 ("terminating collapsing obj %p", object)); 941 KASSERT(object->backing_object == NULL, 942 ("terminating shadow obj %p", object)); 943 944 /* 945 * Wait for the pageout daemon and other current users to be 946 * done with the object. Note that new paging_in_progress 947 * users can come after this wait, but they must check 948 * OBJ_DEAD flag set (without unlocking the object), and avoid 949 * the object being terminated. 950 */ 951 vm_object_pip_wait(object, "objtrm"); 952 953 KASSERT(object->ref_count == 0, 954 ("vm_object_terminate: object with references, ref_count=%d", 955 object->ref_count)); 956 957 if ((object->flags & OBJ_PG_DTOR) == 0) 958 vm_object_terminate_pages(object); 959 960 #if VM_NRESERVLEVEL > 0 961 if (__predict_false(!LIST_EMPTY(&object->rvq))) 962 vm_reserv_break_all(object); 963 #endif 964 965 KASSERT(object->cred == NULL || (object->flags & OBJ_SWAP) != 0, 966 ("%s: non-swap obj %p has cred", __func__, object)); 967 968 /* 969 * Let the pager know object is dead. 970 */ 971 vm_pager_deallocate(object); 972 VM_OBJECT_WUNLOCK(object); 973 974 vm_object_destroy(object); 975 } 976 977 /* 978 * Make the page read-only so that we can clear the object flags. However, if 979 * this is a nosync mmap then the object is likely to stay dirty so do not 980 * mess with the page and do not clear the object flags. Returns TRUE if the 981 * page should be flushed, and FALSE otherwise. 982 */ 983 static boolean_t 984 vm_object_page_remove_write(vm_page_t p, int flags, boolean_t *allclean) 985 { 986 987 vm_page_assert_busied(p); 988 989 /* 990 * If we have been asked to skip nosync pages and this is a 991 * nosync page, skip it. Note that the object flags were not 992 * cleared in this case so we do not have to set them. 993 */ 994 if ((flags & OBJPC_NOSYNC) != 0 && (p->a.flags & PGA_NOSYNC) != 0) { 995 *allclean = FALSE; 996 return (FALSE); 997 } else { 998 pmap_remove_write(p); 999 return (p->dirty != 0); 1000 } 1001 } 1002 1003 /* 1004 * vm_object_page_clean 1005 * 1006 * Clean all dirty pages in the specified range of object. Leaves page 1007 * on whatever queue it is currently on. If NOSYNC is set then do not 1008 * write out pages with PGA_NOSYNC set (originally comes from MAP_NOSYNC), 1009 * leaving the object dirty. 1010 * 1011 * For swap objects backing tmpfs regular files, do not flush anything, 1012 * but remove write protection on the mapped pages to update mtime through 1013 * mmaped writes. 1014 * 1015 * When stuffing pages asynchronously, allow clustering. XXX we need a 1016 * synchronous clustering mode implementation. 1017 * 1018 * Odd semantics: if start == end, we clean everything. 1019 * 1020 * The object must be locked. 1021 * 1022 * Returns FALSE if some page from the range was not written, as 1023 * reported by the pager, and TRUE otherwise. 1024 */ 1025 boolean_t 1026 vm_object_page_clean(vm_object_t object, vm_ooffset_t start, vm_ooffset_t end, 1027 int flags) 1028 { 1029 vm_page_t np, p; 1030 vm_pindex_t pi, tend, tstart; 1031 int curgeneration, n, pagerflags; 1032 boolean_t eio, res, allclean; 1033 1034 VM_OBJECT_ASSERT_WLOCKED(object); 1035 1036 if (!vm_object_mightbedirty(object) || object->resident_page_count == 0) 1037 return (TRUE); 1038 1039 pagerflags = (flags & (OBJPC_SYNC | OBJPC_INVAL)) != 0 ? 1040 VM_PAGER_PUT_SYNC : VM_PAGER_CLUSTER_OK; 1041 pagerflags |= (flags & OBJPC_INVAL) != 0 ? VM_PAGER_PUT_INVAL : 0; 1042 1043 tstart = OFF_TO_IDX(start); 1044 tend = (end == 0) ? object->size : OFF_TO_IDX(end + PAGE_MASK); 1045 allclean = tstart == 0 && tend >= object->size; 1046 res = TRUE; 1047 1048 rescan: 1049 curgeneration = object->generation; 1050 1051 for (p = vm_page_find_least(object, tstart); p != NULL; p = np) { 1052 pi = p->pindex; 1053 if (pi >= tend) 1054 break; 1055 np = TAILQ_NEXT(p, listq); 1056 if (vm_page_none_valid(p)) 1057 continue; 1058 if (vm_page_busy_acquire(p, VM_ALLOC_WAITFAIL) == 0) { 1059 if (object->generation != curgeneration && 1060 (flags & OBJPC_SYNC) != 0) 1061 goto rescan; 1062 np = vm_page_find_least(object, pi); 1063 continue; 1064 } 1065 if (!vm_object_page_remove_write(p, flags, &allclean)) { 1066 vm_page_xunbusy(p); 1067 continue; 1068 } 1069 if (object->type == OBJT_VNODE) { 1070 n = vm_object_page_collect_flush(object, p, pagerflags, 1071 flags, &allclean, &eio); 1072 if (eio) { 1073 res = FALSE; 1074 allclean = FALSE; 1075 } 1076 if (object->generation != curgeneration && 1077 (flags & OBJPC_SYNC) != 0) 1078 goto rescan; 1079 1080 /* 1081 * If the VOP_PUTPAGES() did a truncated write, so 1082 * that even the first page of the run is not fully 1083 * written, vm_pageout_flush() returns 0 as the run 1084 * length. Since the condition that caused truncated 1085 * write may be permanent, e.g. exhausted free space, 1086 * accepting n == 0 would cause an infinite loop. 1087 * 1088 * Forwarding the iterator leaves the unwritten page 1089 * behind, but there is not much we can do there if 1090 * filesystem refuses to write it. 1091 */ 1092 if (n == 0) { 1093 n = 1; 1094 allclean = FALSE; 1095 } 1096 } else { 1097 n = 1; 1098 vm_page_xunbusy(p); 1099 } 1100 np = vm_page_find_least(object, pi + n); 1101 } 1102 #if 0 1103 VOP_FSYNC(vp, (pagerflags & VM_PAGER_PUT_SYNC) ? MNT_WAIT : 0); 1104 #endif 1105 1106 /* 1107 * Leave updating cleangeneration for tmpfs objects to tmpfs 1108 * scan. It needs to update mtime, which happens for other 1109 * filesystems during page writeouts. 1110 */ 1111 if (allclean && object->type == OBJT_VNODE) 1112 object->cleangeneration = curgeneration; 1113 return (res); 1114 } 1115 1116 static int 1117 vm_object_page_collect_flush(vm_object_t object, vm_page_t p, int pagerflags, 1118 int flags, boolean_t *allclean, boolean_t *eio) 1119 { 1120 vm_page_t ma[vm_pageout_page_count], p_first, tp; 1121 int count, i, mreq, runlen; 1122 1123 vm_page_lock_assert(p, MA_NOTOWNED); 1124 vm_page_assert_xbusied(p); 1125 VM_OBJECT_ASSERT_WLOCKED(object); 1126 1127 count = 1; 1128 mreq = 0; 1129 1130 for (tp = p; count < vm_pageout_page_count; count++) { 1131 tp = vm_page_next(tp); 1132 if (tp == NULL || vm_page_tryxbusy(tp) == 0) 1133 break; 1134 if (!vm_object_page_remove_write(tp, flags, allclean)) { 1135 vm_page_xunbusy(tp); 1136 break; 1137 } 1138 } 1139 1140 for (p_first = p; count < vm_pageout_page_count; count++) { 1141 tp = vm_page_prev(p_first); 1142 if (tp == NULL || vm_page_tryxbusy(tp) == 0) 1143 break; 1144 if (!vm_object_page_remove_write(tp, flags, allclean)) { 1145 vm_page_xunbusy(tp); 1146 break; 1147 } 1148 p_first = tp; 1149 mreq++; 1150 } 1151 1152 for (tp = p_first, i = 0; i < count; tp = TAILQ_NEXT(tp, listq), i++) 1153 ma[i] = tp; 1154 1155 vm_pageout_flush(ma, count, pagerflags, mreq, &runlen, eio); 1156 return (runlen); 1157 } 1158 1159 /* 1160 * Note that there is absolutely no sense in writing out 1161 * anonymous objects, so we track down the vnode object 1162 * to write out. 1163 * We invalidate (remove) all pages from the address space 1164 * for semantic correctness. 1165 * 1166 * If the backing object is a device object with unmanaged pages, then any 1167 * mappings to the specified range of pages must be removed before this 1168 * function is called. 1169 * 1170 * Note: certain anonymous maps, such as MAP_NOSYNC maps, 1171 * may start out with a NULL object. 1172 */ 1173 boolean_t 1174 vm_object_sync(vm_object_t object, vm_ooffset_t offset, vm_size_t size, 1175 boolean_t syncio, boolean_t invalidate) 1176 { 1177 vm_object_t backing_object; 1178 struct vnode *vp; 1179 struct mount *mp; 1180 int error, flags, fsync_after; 1181 boolean_t res; 1182 1183 if (object == NULL) 1184 return (TRUE); 1185 res = TRUE; 1186 error = 0; 1187 VM_OBJECT_WLOCK(object); 1188 while ((backing_object = object->backing_object) != NULL) { 1189 VM_OBJECT_WLOCK(backing_object); 1190 offset += object->backing_object_offset; 1191 VM_OBJECT_WUNLOCK(object); 1192 object = backing_object; 1193 if (object->size < OFF_TO_IDX(offset + size)) 1194 size = IDX_TO_OFF(object->size) - offset; 1195 } 1196 /* 1197 * Flush pages if writing is allowed, invalidate them 1198 * if invalidation requested. Pages undergoing I/O 1199 * will be ignored by vm_object_page_remove(). 1200 * 1201 * We cannot lock the vnode and then wait for paging 1202 * to complete without deadlocking against vm_fault. 1203 * Instead we simply call vm_object_page_remove() and 1204 * allow it to block internally on a page-by-page 1205 * basis when it encounters pages undergoing async 1206 * I/O. 1207 */ 1208 if (object->type == OBJT_VNODE && 1209 vm_object_mightbedirty(object) != 0 && 1210 ((vp = object->handle)->v_vflag & VV_NOSYNC) == 0) { 1211 VM_OBJECT_WUNLOCK(object); 1212 (void)vn_start_write(vp, &mp, V_WAIT); 1213 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY); 1214 if (syncio && !invalidate && offset == 0 && 1215 atop(size) == object->size) { 1216 /* 1217 * If syncing the whole mapping of the file, 1218 * it is faster to schedule all the writes in 1219 * async mode, also allowing the clustering, 1220 * and then wait for i/o to complete. 1221 */ 1222 flags = 0; 1223 fsync_after = TRUE; 1224 } else { 1225 flags = (syncio || invalidate) ? OBJPC_SYNC : 0; 1226 flags |= invalidate ? (OBJPC_SYNC | OBJPC_INVAL) : 0; 1227 fsync_after = FALSE; 1228 } 1229 VM_OBJECT_WLOCK(object); 1230 res = vm_object_page_clean(object, offset, offset + size, 1231 flags); 1232 VM_OBJECT_WUNLOCK(object); 1233 if (fsync_after) { 1234 for (;;) { 1235 error = VOP_FSYNC(vp, MNT_WAIT, curthread); 1236 if (error != ERELOOKUP) 1237 break; 1238 1239 /* 1240 * Allow SU/bufdaemon to handle more 1241 * dependencies in the meantime. 1242 */ 1243 VOP_UNLOCK(vp); 1244 vn_finished_write(mp); 1245 1246 (void)vn_start_write(vp, &mp, V_WAIT); 1247 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY); 1248 } 1249 } 1250 VOP_UNLOCK(vp); 1251 vn_finished_write(mp); 1252 if (error != 0) 1253 res = FALSE; 1254 VM_OBJECT_WLOCK(object); 1255 } 1256 if ((object->type == OBJT_VNODE || 1257 object->type == OBJT_DEVICE) && invalidate) { 1258 if (object->type == OBJT_DEVICE) 1259 /* 1260 * The option OBJPR_NOTMAPPED must be passed here 1261 * because vm_object_page_remove() cannot remove 1262 * unmanaged mappings. 1263 */ 1264 flags = OBJPR_NOTMAPPED; 1265 else if (old_msync) 1266 flags = 0; 1267 else 1268 flags = OBJPR_CLEANONLY; 1269 vm_object_page_remove(object, OFF_TO_IDX(offset), 1270 OFF_TO_IDX(offset + size + PAGE_MASK), flags); 1271 } 1272 VM_OBJECT_WUNLOCK(object); 1273 return (res); 1274 } 1275 1276 /* 1277 * Determine whether the given advice can be applied to the object. Advice is 1278 * not applied to unmanaged pages since they never belong to page queues, and 1279 * since MADV_FREE is destructive, it can apply only to anonymous pages that 1280 * have been mapped at most once. 1281 */ 1282 static bool 1283 vm_object_advice_applies(vm_object_t object, int advice) 1284 { 1285 1286 if ((object->flags & OBJ_UNMANAGED) != 0) 1287 return (false); 1288 if (advice != MADV_FREE) 1289 return (true); 1290 return ((object->flags & (OBJ_ONEMAPPING | OBJ_ANON)) == 1291 (OBJ_ONEMAPPING | OBJ_ANON)); 1292 } 1293 1294 static void 1295 vm_object_madvise_freespace(vm_object_t object, int advice, vm_pindex_t pindex, 1296 vm_size_t size) 1297 { 1298 1299 if (advice == MADV_FREE) 1300 vm_pager_freespace(object, pindex, size); 1301 } 1302 1303 /* 1304 * vm_object_madvise: 1305 * 1306 * Implements the madvise function at the object/page level. 1307 * 1308 * MADV_WILLNEED (any object) 1309 * 1310 * Activate the specified pages if they are resident. 1311 * 1312 * MADV_DONTNEED (any object) 1313 * 1314 * Deactivate the specified pages if they are resident. 1315 * 1316 * MADV_FREE (OBJT_SWAP objects, OBJ_ONEMAPPING only) 1317 * 1318 * Deactivate and clean the specified pages if they are 1319 * resident. This permits the process to reuse the pages 1320 * without faulting or the kernel to reclaim the pages 1321 * without I/O. 1322 */ 1323 void 1324 vm_object_madvise(vm_object_t object, vm_pindex_t pindex, vm_pindex_t end, 1325 int advice) 1326 { 1327 vm_pindex_t tpindex; 1328 vm_object_t backing_object, tobject; 1329 vm_page_t m, tm; 1330 1331 if (object == NULL) 1332 return; 1333 1334 relookup: 1335 VM_OBJECT_WLOCK(object); 1336 if (!vm_object_advice_applies(object, advice)) { 1337 VM_OBJECT_WUNLOCK(object); 1338 return; 1339 } 1340 for (m = vm_page_find_least(object, pindex); pindex < end; pindex++) { 1341 tobject = object; 1342 1343 /* 1344 * If the next page isn't resident in the top-level object, we 1345 * need to search the shadow chain. When applying MADV_FREE, we 1346 * take care to release any swap space used to store 1347 * non-resident pages. 1348 */ 1349 if (m == NULL || pindex < m->pindex) { 1350 /* 1351 * Optimize a common case: if the top-level object has 1352 * no backing object, we can skip over the non-resident 1353 * range in constant time. 1354 */ 1355 if (object->backing_object == NULL) { 1356 tpindex = (m != NULL && m->pindex < end) ? 1357 m->pindex : end; 1358 vm_object_madvise_freespace(object, advice, 1359 pindex, tpindex - pindex); 1360 if ((pindex = tpindex) == end) 1361 break; 1362 goto next_page; 1363 } 1364 1365 tpindex = pindex; 1366 do { 1367 vm_object_madvise_freespace(tobject, advice, 1368 tpindex, 1); 1369 /* 1370 * Prepare to search the next object in the 1371 * chain. 1372 */ 1373 backing_object = tobject->backing_object; 1374 if (backing_object == NULL) 1375 goto next_pindex; 1376 VM_OBJECT_WLOCK(backing_object); 1377 tpindex += 1378 OFF_TO_IDX(tobject->backing_object_offset); 1379 if (tobject != object) 1380 VM_OBJECT_WUNLOCK(tobject); 1381 tobject = backing_object; 1382 if (!vm_object_advice_applies(tobject, advice)) 1383 goto next_pindex; 1384 } while ((tm = vm_page_lookup(tobject, tpindex)) == 1385 NULL); 1386 } else { 1387 next_page: 1388 tm = m; 1389 m = TAILQ_NEXT(m, listq); 1390 } 1391 1392 /* 1393 * If the page is not in a normal state, skip it. The page 1394 * can not be invalidated while the object lock is held. 1395 */ 1396 if (!vm_page_all_valid(tm) || vm_page_wired(tm)) 1397 goto next_pindex; 1398 KASSERT((tm->flags & PG_FICTITIOUS) == 0, 1399 ("vm_object_madvise: page %p is fictitious", tm)); 1400 KASSERT((tm->oflags & VPO_UNMANAGED) == 0, 1401 ("vm_object_madvise: page %p is not managed", tm)); 1402 if (vm_page_tryxbusy(tm) == 0) { 1403 if (object != tobject) 1404 VM_OBJECT_WUNLOCK(object); 1405 if (advice == MADV_WILLNEED) { 1406 /* 1407 * Reference the page before unlocking and 1408 * sleeping so that the page daemon is less 1409 * likely to reclaim it. 1410 */ 1411 vm_page_aflag_set(tm, PGA_REFERENCED); 1412 } 1413 if (!vm_page_busy_sleep(tm, "madvpo", 0)) 1414 VM_OBJECT_WUNLOCK(tobject); 1415 goto relookup; 1416 } 1417 vm_page_advise(tm, advice); 1418 vm_page_xunbusy(tm); 1419 vm_object_madvise_freespace(tobject, advice, tm->pindex, 1); 1420 next_pindex: 1421 if (tobject != object) 1422 VM_OBJECT_WUNLOCK(tobject); 1423 } 1424 VM_OBJECT_WUNLOCK(object); 1425 } 1426 1427 /* 1428 * vm_object_shadow: 1429 * 1430 * Create a new object which is backed by the 1431 * specified existing object range. The source 1432 * object reference is deallocated. 1433 * 1434 * The new object and offset into that object 1435 * are returned in the source parameters. 1436 */ 1437 void 1438 vm_object_shadow(vm_object_t *object, vm_ooffset_t *offset, vm_size_t length, 1439 struct ucred *cred, bool shared) 1440 { 1441 vm_object_t source; 1442 vm_object_t result; 1443 1444 source = *object; 1445 1446 /* 1447 * Don't create the new object if the old object isn't shared. 1448 * 1449 * If we hold the only reference we can guarantee that it won't 1450 * increase while we have the map locked. Otherwise the race is 1451 * harmless and we will end up with an extra shadow object that 1452 * will be collapsed later. 1453 */ 1454 if (source != NULL && source->ref_count == 1 && 1455 (source->flags & OBJ_ANON) != 0) 1456 return; 1457 1458 /* 1459 * Allocate a new object with the given length. 1460 */ 1461 result = vm_object_allocate_anon(atop(length), source, cred, length); 1462 1463 /* 1464 * Store the offset into the source object, and fix up the offset into 1465 * the new object. 1466 */ 1467 result->backing_object_offset = *offset; 1468 1469 if (shared || source != NULL) { 1470 VM_OBJECT_WLOCK(result); 1471 1472 /* 1473 * The new object shadows the source object, adding a 1474 * reference to it. Our caller changes his reference 1475 * to point to the new object, removing a reference to 1476 * the source object. Net result: no change of 1477 * reference count, unless the caller needs to add one 1478 * more reference due to forking a shared map entry. 1479 */ 1480 if (shared) { 1481 vm_object_reference_locked(result); 1482 vm_object_clear_flag(result, OBJ_ONEMAPPING); 1483 } 1484 1485 /* 1486 * Try to optimize the result object's page color when 1487 * shadowing in order to maintain page coloring 1488 * consistency in the combined shadowed object. 1489 */ 1490 if (source != NULL) { 1491 vm_object_backing_insert(result, source); 1492 result->domain = source->domain; 1493 #if VM_NRESERVLEVEL > 0 1494 vm_object_set_flag(result, 1495 (source->flags & OBJ_COLORED)); 1496 result->pg_color = (source->pg_color + 1497 OFF_TO_IDX(*offset)) & ((1 << (VM_NFREEORDER - 1498 1)) - 1); 1499 #endif 1500 } 1501 VM_OBJECT_WUNLOCK(result); 1502 } 1503 1504 /* 1505 * Return the new things 1506 */ 1507 *offset = 0; 1508 *object = result; 1509 } 1510 1511 /* 1512 * vm_object_split: 1513 * 1514 * Split the pages in a map entry into a new object. This affords 1515 * easier removal of unused pages, and keeps object inheritance from 1516 * being a negative impact on memory usage. 1517 */ 1518 void 1519 vm_object_split(vm_map_entry_t entry) 1520 { 1521 vm_page_t m, m_next; 1522 vm_object_t orig_object, new_object, backing_object; 1523 vm_pindex_t idx, offidxstart; 1524 vm_size_t size; 1525 1526 orig_object = entry->object.vm_object; 1527 KASSERT((orig_object->flags & OBJ_ONEMAPPING) != 0, 1528 ("vm_object_split: Splitting object with multiple mappings.")); 1529 if ((orig_object->flags & OBJ_ANON) == 0) 1530 return; 1531 if (orig_object->ref_count <= 1) 1532 return; 1533 VM_OBJECT_WUNLOCK(orig_object); 1534 1535 offidxstart = OFF_TO_IDX(entry->offset); 1536 size = atop(entry->end - entry->start); 1537 1538 new_object = vm_object_allocate_anon(size, orig_object, 1539 orig_object->cred, ptoa(size)); 1540 1541 /* 1542 * We must wait for the orig_object to complete any in-progress 1543 * collapse so that the swap blocks are stable below. The 1544 * additional reference on backing_object by new object will 1545 * prevent further collapse operations until split completes. 1546 */ 1547 VM_OBJECT_WLOCK(orig_object); 1548 vm_object_collapse_wait(orig_object); 1549 1550 /* 1551 * At this point, the new object is still private, so the order in 1552 * which the original and new objects are locked does not matter. 1553 */ 1554 VM_OBJECT_WLOCK(new_object); 1555 new_object->domain = orig_object->domain; 1556 backing_object = orig_object->backing_object; 1557 if (backing_object != NULL) { 1558 vm_object_backing_insert_ref(new_object, backing_object); 1559 new_object->backing_object_offset = 1560 orig_object->backing_object_offset + entry->offset; 1561 } 1562 if (orig_object->cred != NULL) { 1563 crhold(orig_object->cred); 1564 KASSERT(orig_object->charge >= ptoa(size), 1565 ("orig_object->charge < 0")); 1566 orig_object->charge -= ptoa(size); 1567 } 1568 1569 /* 1570 * Mark the split operation so that swap_pager_getpages() knows 1571 * that the object is in transition. 1572 */ 1573 vm_object_set_flag(orig_object, OBJ_SPLIT); 1574 #ifdef INVARIANTS 1575 idx = 0; 1576 #endif 1577 retry: 1578 m = vm_page_find_least(orig_object, offidxstart); 1579 KASSERT(m == NULL || idx <= m->pindex - offidxstart, 1580 ("%s: object %p was repopulated", __func__, orig_object)); 1581 for (; m != NULL && (idx = m->pindex - offidxstart) < size; 1582 m = m_next) { 1583 m_next = TAILQ_NEXT(m, listq); 1584 1585 /* 1586 * We must wait for pending I/O to complete before we can 1587 * rename the page. 1588 * 1589 * We do not have to VM_PROT_NONE the page as mappings should 1590 * not be changed by this operation. 1591 */ 1592 if (vm_page_tryxbusy(m) == 0) { 1593 VM_OBJECT_WUNLOCK(new_object); 1594 if (vm_page_busy_sleep(m, "spltwt", 0)) 1595 VM_OBJECT_WLOCK(orig_object); 1596 VM_OBJECT_WLOCK(new_object); 1597 goto retry; 1598 } 1599 1600 /* 1601 * The page was left invalid. Likely placed there by 1602 * an incomplete fault. Just remove and ignore. 1603 */ 1604 if (vm_page_none_valid(m)) { 1605 if (vm_page_remove(m)) 1606 vm_page_free(m); 1607 continue; 1608 } 1609 1610 /* vm_page_rename() will dirty the page. */ 1611 if (vm_page_rename(m, new_object, idx)) { 1612 vm_page_xunbusy(m); 1613 VM_OBJECT_WUNLOCK(new_object); 1614 VM_OBJECT_WUNLOCK(orig_object); 1615 vm_radix_wait(); 1616 VM_OBJECT_WLOCK(orig_object); 1617 VM_OBJECT_WLOCK(new_object); 1618 goto retry; 1619 } 1620 1621 #if VM_NRESERVLEVEL > 0 1622 /* 1623 * If some of the reservation's allocated pages remain with 1624 * the original object, then transferring the reservation to 1625 * the new object is neither particularly beneficial nor 1626 * particularly harmful as compared to leaving the reservation 1627 * with the original object. If, however, all of the 1628 * reservation's allocated pages are transferred to the new 1629 * object, then transferring the reservation is typically 1630 * beneficial. Determining which of these two cases applies 1631 * would be more costly than unconditionally renaming the 1632 * reservation. 1633 */ 1634 vm_reserv_rename(m, new_object, orig_object, offidxstart); 1635 #endif 1636 } 1637 1638 /* 1639 * swap_pager_copy() can sleep, in which case the orig_object's 1640 * and new_object's locks are released and reacquired. 1641 */ 1642 swap_pager_copy(orig_object, new_object, offidxstart, 0); 1643 1644 TAILQ_FOREACH(m, &new_object->memq, listq) 1645 vm_page_xunbusy(m); 1646 1647 vm_object_clear_flag(orig_object, OBJ_SPLIT); 1648 VM_OBJECT_WUNLOCK(orig_object); 1649 VM_OBJECT_WUNLOCK(new_object); 1650 entry->object.vm_object = new_object; 1651 entry->offset = 0LL; 1652 vm_object_deallocate(orig_object); 1653 VM_OBJECT_WLOCK(new_object); 1654 } 1655 1656 static vm_page_t 1657 vm_object_collapse_scan_wait(vm_object_t object, vm_page_t p) 1658 { 1659 vm_object_t backing_object; 1660 1661 VM_OBJECT_ASSERT_WLOCKED(object); 1662 backing_object = object->backing_object; 1663 VM_OBJECT_ASSERT_WLOCKED(backing_object); 1664 1665 KASSERT(p == NULL || p->object == object || p->object == backing_object, 1666 ("invalid ownership %p %p %p", p, object, backing_object)); 1667 /* The page is only NULL when rename fails. */ 1668 if (p == NULL) { 1669 VM_OBJECT_WUNLOCK(object); 1670 VM_OBJECT_WUNLOCK(backing_object); 1671 vm_radix_wait(); 1672 VM_OBJECT_WLOCK(object); 1673 } else if (p->object == object) { 1674 VM_OBJECT_WUNLOCK(backing_object); 1675 if (vm_page_busy_sleep(p, "vmocol", 0)) 1676 VM_OBJECT_WLOCK(object); 1677 } else { 1678 VM_OBJECT_WUNLOCK(object); 1679 if (!vm_page_busy_sleep(p, "vmocol", 0)) 1680 VM_OBJECT_WUNLOCK(backing_object); 1681 VM_OBJECT_WLOCK(object); 1682 } 1683 VM_OBJECT_WLOCK(backing_object); 1684 return (TAILQ_FIRST(&backing_object->memq)); 1685 } 1686 1687 static bool 1688 vm_object_scan_all_shadowed(vm_object_t object) 1689 { 1690 vm_object_t backing_object; 1691 vm_page_t p, pp; 1692 vm_pindex_t backing_offset_index, new_pindex, pi, ps; 1693 1694 VM_OBJECT_ASSERT_WLOCKED(object); 1695 VM_OBJECT_ASSERT_WLOCKED(object->backing_object); 1696 1697 backing_object = object->backing_object; 1698 1699 if ((backing_object->flags & OBJ_ANON) == 0) 1700 return (false); 1701 1702 pi = backing_offset_index = OFF_TO_IDX(object->backing_object_offset); 1703 p = vm_page_find_least(backing_object, pi); 1704 ps = swap_pager_find_least(backing_object, pi); 1705 1706 /* 1707 * Only check pages inside the parent object's range and 1708 * inside the parent object's mapping of the backing object. 1709 */ 1710 for (;; pi++) { 1711 if (p != NULL && p->pindex < pi) 1712 p = TAILQ_NEXT(p, listq); 1713 if (ps < pi) 1714 ps = swap_pager_find_least(backing_object, pi); 1715 if (p == NULL && ps >= backing_object->size) 1716 break; 1717 else if (p == NULL) 1718 pi = ps; 1719 else 1720 pi = MIN(p->pindex, ps); 1721 1722 new_pindex = pi - backing_offset_index; 1723 if (new_pindex >= object->size) 1724 break; 1725 1726 if (p != NULL) { 1727 /* 1728 * If the backing object page is busy a 1729 * grandparent or older page may still be 1730 * undergoing CoW. It is not safe to collapse 1731 * the backing object until it is quiesced. 1732 */ 1733 if (vm_page_tryxbusy(p) == 0) 1734 return (false); 1735 1736 /* 1737 * We raced with the fault handler that left 1738 * newly allocated invalid page on the object 1739 * queue and retried. 1740 */ 1741 if (!vm_page_all_valid(p)) 1742 goto unbusy_ret; 1743 } 1744 1745 /* 1746 * See if the parent has the page or if the parent's object 1747 * pager has the page. If the parent has the page but the page 1748 * is not valid, the parent's object pager must have the page. 1749 * 1750 * If this fails, the parent does not completely shadow the 1751 * object and we might as well give up now. 1752 */ 1753 pp = vm_page_lookup(object, new_pindex); 1754 1755 /* 1756 * The valid check here is stable due to object lock 1757 * being required to clear valid and initiate paging. 1758 * Busy of p disallows fault handler to validate pp. 1759 */ 1760 if ((pp == NULL || vm_page_none_valid(pp)) && 1761 !vm_pager_has_page(object, new_pindex, NULL, NULL)) 1762 goto unbusy_ret; 1763 if (p != NULL) 1764 vm_page_xunbusy(p); 1765 } 1766 return (true); 1767 1768 unbusy_ret: 1769 if (p != NULL) 1770 vm_page_xunbusy(p); 1771 return (false); 1772 } 1773 1774 static void 1775 vm_object_collapse_scan(vm_object_t object) 1776 { 1777 vm_object_t backing_object; 1778 vm_page_t next, p, pp; 1779 vm_pindex_t backing_offset_index, new_pindex; 1780 1781 VM_OBJECT_ASSERT_WLOCKED(object); 1782 VM_OBJECT_ASSERT_WLOCKED(object->backing_object); 1783 1784 backing_object = object->backing_object; 1785 backing_offset_index = OFF_TO_IDX(object->backing_object_offset); 1786 1787 /* 1788 * Our scan 1789 */ 1790 for (p = TAILQ_FIRST(&backing_object->memq); p != NULL; p = next) { 1791 next = TAILQ_NEXT(p, listq); 1792 new_pindex = p->pindex - backing_offset_index; 1793 1794 /* 1795 * Check for busy page 1796 */ 1797 if (vm_page_tryxbusy(p) == 0) { 1798 next = vm_object_collapse_scan_wait(object, p); 1799 continue; 1800 } 1801 1802 KASSERT(object->backing_object == backing_object, 1803 ("vm_object_collapse_scan: backing object mismatch %p != %p", 1804 object->backing_object, backing_object)); 1805 KASSERT(p->object == backing_object, 1806 ("vm_object_collapse_scan: object mismatch %p != %p", 1807 p->object, backing_object)); 1808 1809 if (p->pindex < backing_offset_index || 1810 new_pindex >= object->size) { 1811 vm_pager_freespace(backing_object, p->pindex, 1); 1812 1813 KASSERT(!pmap_page_is_mapped(p), 1814 ("freeing mapped page %p", p)); 1815 if (vm_page_remove(p)) 1816 vm_page_free(p); 1817 continue; 1818 } 1819 1820 if (!vm_page_all_valid(p)) { 1821 KASSERT(!pmap_page_is_mapped(p), 1822 ("freeing mapped page %p", p)); 1823 if (vm_page_remove(p)) 1824 vm_page_free(p); 1825 continue; 1826 } 1827 1828 pp = vm_page_lookup(object, new_pindex); 1829 if (pp != NULL && vm_page_tryxbusy(pp) == 0) { 1830 vm_page_xunbusy(p); 1831 /* 1832 * The page in the parent is busy and possibly not 1833 * (yet) valid. Until its state is finalized by the 1834 * busy bit owner, we can't tell whether it shadows the 1835 * original page. 1836 */ 1837 next = vm_object_collapse_scan_wait(object, pp); 1838 continue; 1839 } 1840 1841 if (pp != NULL && vm_page_none_valid(pp)) { 1842 /* 1843 * The page was invalid in the parent. Likely placed 1844 * there by an incomplete fault. Just remove and 1845 * ignore. p can replace it. 1846 */ 1847 if (vm_page_remove(pp)) 1848 vm_page_free(pp); 1849 pp = NULL; 1850 } 1851 1852 if (pp != NULL || vm_pager_has_page(object, new_pindex, NULL, 1853 NULL)) { 1854 /* 1855 * The page already exists in the parent OR swap exists 1856 * for this location in the parent. Leave the parent's 1857 * page alone. Destroy the original page from the 1858 * backing object. 1859 */ 1860 vm_pager_freespace(backing_object, p->pindex, 1); 1861 KASSERT(!pmap_page_is_mapped(p), 1862 ("freeing mapped page %p", p)); 1863 if (vm_page_remove(p)) 1864 vm_page_free(p); 1865 if (pp != NULL) 1866 vm_page_xunbusy(pp); 1867 continue; 1868 } 1869 1870 /* 1871 * Page does not exist in parent, rename the page from the 1872 * backing object to the main object. 1873 * 1874 * If the page was mapped to a process, it can remain mapped 1875 * through the rename. vm_page_rename() will dirty the page. 1876 */ 1877 if (vm_page_rename(p, object, new_pindex)) { 1878 vm_page_xunbusy(p); 1879 next = vm_object_collapse_scan_wait(object, NULL); 1880 continue; 1881 } 1882 1883 /* Use the old pindex to free the right page. */ 1884 vm_pager_freespace(backing_object, new_pindex + 1885 backing_offset_index, 1); 1886 1887 #if VM_NRESERVLEVEL > 0 1888 /* 1889 * Rename the reservation. 1890 */ 1891 vm_reserv_rename(p, object, backing_object, 1892 backing_offset_index); 1893 #endif 1894 vm_page_xunbusy(p); 1895 } 1896 return; 1897 } 1898 1899 /* 1900 * vm_object_collapse: 1901 * 1902 * Collapse an object with the object backing it. 1903 * Pages in the backing object are moved into the 1904 * parent, and the backing object is deallocated. 1905 */ 1906 void 1907 vm_object_collapse(vm_object_t object) 1908 { 1909 vm_object_t backing_object, new_backing_object; 1910 1911 VM_OBJECT_ASSERT_WLOCKED(object); 1912 1913 while (TRUE) { 1914 KASSERT((object->flags & (OBJ_DEAD | OBJ_ANON)) == OBJ_ANON, 1915 ("collapsing invalid object")); 1916 1917 /* 1918 * Wait for the backing_object to finish any pending 1919 * collapse so that the caller sees the shortest possible 1920 * shadow chain. 1921 */ 1922 backing_object = vm_object_backing_collapse_wait(object); 1923 if (backing_object == NULL) 1924 return; 1925 1926 KASSERT(object->ref_count > 0 && 1927 object->ref_count > atomic_load_int(&object->shadow_count), 1928 ("collapse with invalid ref %d or shadow %d count.", 1929 object->ref_count, atomic_load_int(&object->shadow_count))); 1930 KASSERT((backing_object->flags & 1931 (OBJ_COLLAPSING | OBJ_DEAD)) == 0, 1932 ("vm_object_collapse: Backing object already collapsing.")); 1933 KASSERT((object->flags & (OBJ_COLLAPSING | OBJ_DEAD)) == 0, 1934 ("vm_object_collapse: object is already collapsing.")); 1935 1936 /* 1937 * We know that we can either collapse the backing object if 1938 * the parent is the only reference to it, or (perhaps) have 1939 * the parent bypass the object if the parent happens to shadow 1940 * all the resident pages in the entire backing object. 1941 */ 1942 if (backing_object->ref_count == 1) { 1943 KASSERT(atomic_load_int(&backing_object->shadow_count) 1944 == 1, 1945 ("vm_object_collapse: shadow_count: %d", 1946 atomic_load_int(&backing_object->shadow_count))); 1947 vm_object_pip_add(object, 1); 1948 vm_object_set_flag(object, OBJ_COLLAPSING); 1949 vm_object_pip_add(backing_object, 1); 1950 vm_object_set_flag(backing_object, OBJ_DEAD); 1951 1952 /* 1953 * If there is exactly one reference to the backing 1954 * object, we can collapse it into the parent. 1955 */ 1956 vm_object_collapse_scan(object); 1957 1958 #if VM_NRESERVLEVEL > 0 1959 /* 1960 * Break any reservations from backing_object. 1961 */ 1962 if (__predict_false(!LIST_EMPTY(&backing_object->rvq))) 1963 vm_reserv_break_all(backing_object); 1964 #endif 1965 1966 /* 1967 * Move the pager from backing_object to object. 1968 * 1969 * swap_pager_copy() can sleep, in which case the 1970 * backing_object's and object's locks are released and 1971 * reacquired. 1972 */ 1973 swap_pager_copy(backing_object, object, 1974 OFF_TO_IDX(object->backing_object_offset), TRUE); 1975 1976 /* 1977 * Object now shadows whatever backing_object did. 1978 */ 1979 vm_object_clear_flag(object, OBJ_COLLAPSING); 1980 vm_object_backing_transfer(object, backing_object); 1981 object->backing_object_offset += 1982 backing_object->backing_object_offset; 1983 VM_OBJECT_WUNLOCK(object); 1984 vm_object_pip_wakeup(object); 1985 1986 /* 1987 * Discard backing_object. 1988 * 1989 * Since the backing object has no pages, no pager left, 1990 * and no object references within it, all that is 1991 * necessary is to dispose of it. 1992 */ 1993 KASSERT(backing_object->ref_count == 1, ( 1994 "backing_object %p was somehow re-referenced during collapse!", 1995 backing_object)); 1996 vm_object_pip_wakeup(backing_object); 1997 (void)refcount_release(&backing_object->ref_count); 1998 vm_object_terminate(backing_object); 1999 counter_u64_add(object_collapses, 1); 2000 VM_OBJECT_WLOCK(object); 2001 } else { 2002 /* 2003 * If we do not entirely shadow the backing object, 2004 * there is nothing we can do so we give up. 2005 * 2006 * The object lock and backing_object lock must not 2007 * be dropped during this sequence. 2008 */ 2009 if (!vm_object_scan_all_shadowed(object)) { 2010 VM_OBJECT_WUNLOCK(backing_object); 2011 break; 2012 } 2013 2014 /* 2015 * Make the parent shadow the next object in the 2016 * chain. Deallocating backing_object will not remove 2017 * it, since its reference count is at least 2. 2018 */ 2019 vm_object_backing_remove_locked(object); 2020 new_backing_object = backing_object->backing_object; 2021 if (new_backing_object != NULL) { 2022 vm_object_backing_insert_ref(object, 2023 new_backing_object); 2024 object->backing_object_offset += 2025 backing_object->backing_object_offset; 2026 } 2027 2028 /* 2029 * Drop the reference count on backing_object. Since 2030 * its ref_count was at least 2, it will not vanish. 2031 */ 2032 (void)refcount_release(&backing_object->ref_count); 2033 KASSERT(backing_object->ref_count >= 1, ( 2034 "backing_object %p was somehow dereferenced during collapse!", 2035 backing_object)); 2036 VM_OBJECT_WUNLOCK(backing_object); 2037 counter_u64_add(object_bypasses, 1); 2038 } 2039 2040 /* 2041 * Try again with this object's new backing object. 2042 */ 2043 } 2044 } 2045 2046 /* 2047 * vm_object_page_remove: 2048 * 2049 * For the given object, either frees or invalidates each of the 2050 * specified pages. In general, a page is freed. However, if a page is 2051 * wired for any reason other than the existence of a managed, wired 2052 * mapping, then it may be invalidated but not removed from the object. 2053 * Pages are specified by the given range ["start", "end") and the option 2054 * OBJPR_CLEANONLY. As a special case, if "end" is zero, then the range 2055 * extends from "start" to the end of the object. If the option 2056 * OBJPR_CLEANONLY is specified, then only the non-dirty pages within the 2057 * specified range are affected. If the option OBJPR_NOTMAPPED is 2058 * specified, then the pages within the specified range must have no 2059 * mappings. Otherwise, if this option is not specified, any mappings to 2060 * the specified pages are removed before the pages are freed or 2061 * invalidated. 2062 * 2063 * In general, this operation should only be performed on objects that 2064 * contain managed pages. There are, however, two exceptions. First, it 2065 * is performed on the kernel and kmem objects by vm_map_entry_delete(). 2066 * Second, it is used by msync(..., MS_INVALIDATE) to invalidate device- 2067 * backed pages. In both of these cases, the option OBJPR_CLEANONLY must 2068 * not be specified and the option OBJPR_NOTMAPPED must be specified. 2069 * 2070 * The object must be locked. 2071 */ 2072 void 2073 vm_object_page_remove(vm_object_t object, vm_pindex_t start, vm_pindex_t end, 2074 int options) 2075 { 2076 vm_page_t p, next; 2077 2078 VM_OBJECT_ASSERT_WLOCKED(object); 2079 KASSERT((object->flags & OBJ_UNMANAGED) == 0 || 2080 (options & (OBJPR_CLEANONLY | OBJPR_NOTMAPPED)) == OBJPR_NOTMAPPED, 2081 ("vm_object_page_remove: illegal options for object %p", object)); 2082 if (object->resident_page_count == 0) 2083 return; 2084 vm_object_pip_add(object, 1); 2085 again: 2086 p = vm_page_find_least(object, start); 2087 2088 /* 2089 * Here, the variable "p" is either (1) the page with the least pindex 2090 * greater than or equal to the parameter "start" or (2) NULL. 2091 */ 2092 for (; p != NULL && (p->pindex < end || end == 0); p = next) { 2093 next = TAILQ_NEXT(p, listq); 2094 2095 /* 2096 * Skip invalid pages if asked to do so. Try to avoid acquiring 2097 * the busy lock, as some consumers rely on this to avoid 2098 * deadlocks. 2099 * 2100 * A thread may concurrently transition the page from invalid to 2101 * valid using only the busy lock, so the result of this check 2102 * is immediately stale. It is up to consumers to handle this, 2103 * for instance by ensuring that all invalid->valid transitions 2104 * happen with a mutex held, as may be possible for a 2105 * filesystem. 2106 */ 2107 if ((options & OBJPR_VALIDONLY) != 0 && vm_page_none_valid(p)) 2108 continue; 2109 2110 /* 2111 * If the page is wired for any reason besides the existence 2112 * of managed, wired mappings, then it cannot be freed. For 2113 * example, fictitious pages, which represent device memory, 2114 * are inherently wired and cannot be freed. They can, 2115 * however, be invalidated if the option OBJPR_CLEANONLY is 2116 * not specified. 2117 */ 2118 if (vm_page_tryxbusy(p) == 0) { 2119 if (vm_page_busy_sleep(p, "vmopar", 0)) 2120 VM_OBJECT_WLOCK(object); 2121 goto again; 2122 } 2123 if ((options & OBJPR_VALIDONLY) != 0 && vm_page_none_valid(p)) { 2124 vm_page_xunbusy(p); 2125 continue; 2126 } 2127 if (vm_page_wired(p)) { 2128 wired: 2129 if ((options & OBJPR_NOTMAPPED) == 0 && 2130 object->ref_count != 0) 2131 pmap_remove_all(p); 2132 if ((options & OBJPR_CLEANONLY) == 0) { 2133 vm_page_invalid(p); 2134 vm_page_undirty(p); 2135 } 2136 vm_page_xunbusy(p); 2137 continue; 2138 } 2139 KASSERT((p->flags & PG_FICTITIOUS) == 0, 2140 ("vm_object_page_remove: page %p is fictitious", p)); 2141 if ((options & OBJPR_CLEANONLY) != 0 && 2142 !vm_page_none_valid(p)) { 2143 if ((options & OBJPR_NOTMAPPED) == 0 && 2144 object->ref_count != 0 && 2145 !vm_page_try_remove_write(p)) 2146 goto wired; 2147 if (p->dirty != 0) { 2148 vm_page_xunbusy(p); 2149 continue; 2150 } 2151 } 2152 if ((options & OBJPR_NOTMAPPED) == 0 && 2153 object->ref_count != 0 && !vm_page_try_remove_all(p)) 2154 goto wired; 2155 vm_page_free(p); 2156 } 2157 vm_object_pip_wakeup(object); 2158 2159 vm_pager_freespace(object, start, (end == 0 ? object->size : end) - 2160 start); 2161 } 2162 2163 /* 2164 * vm_object_page_noreuse: 2165 * 2166 * For the given object, attempt to move the specified pages to 2167 * the head of the inactive queue. This bypasses regular LRU 2168 * operation and allows the pages to be reused quickly under memory 2169 * pressure. If a page is wired for any reason, then it will not 2170 * be queued. Pages are specified by the range ["start", "end"). 2171 * As a special case, if "end" is zero, then the range extends from 2172 * "start" to the end of the object. 2173 * 2174 * This operation should only be performed on objects that 2175 * contain non-fictitious, managed pages. 2176 * 2177 * The object must be locked. 2178 */ 2179 void 2180 vm_object_page_noreuse(vm_object_t object, vm_pindex_t start, vm_pindex_t end) 2181 { 2182 vm_page_t p, next; 2183 2184 VM_OBJECT_ASSERT_LOCKED(object); 2185 KASSERT((object->flags & (OBJ_FICTITIOUS | OBJ_UNMANAGED)) == 0, 2186 ("vm_object_page_noreuse: illegal object %p", object)); 2187 if (object->resident_page_count == 0) 2188 return; 2189 p = vm_page_find_least(object, start); 2190 2191 /* 2192 * Here, the variable "p" is either (1) the page with the least pindex 2193 * greater than or equal to the parameter "start" or (2) NULL. 2194 */ 2195 for (; p != NULL && (p->pindex < end || end == 0); p = next) { 2196 next = TAILQ_NEXT(p, listq); 2197 vm_page_deactivate_noreuse(p); 2198 } 2199 } 2200 2201 /* 2202 * Populate the specified range of the object with valid pages. Returns 2203 * TRUE if the range is successfully populated and FALSE otherwise. 2204 * 2205 * Note: This function should be optimized to pass a larger array of 2206 * pages to vm_pager_get_pages() before it is applied to a non- 2207 * OBJT_DEVICE object. 2208 * 2209 * The object must be locked. 2210 */ 2211 boolean_t 2212 vm_object_populate(vm_object_t object, vm_pindex_t start, vm_pindex_t end) 2213 { 2214 vm_page_t m; 2215 vm_pindex_t pindex; 2216 int rv; 2217 2218 VM_OBJECT_ASSERT_WLOCKED(object); 2219 for (pindex = start; pindex < end; pindex++) { 2220 rv = vm_page_grab_valid(&m, object, pindex, VM_ALLOC_NORMAL); 2221 if (rv != VM_PAGER_OK) 2222 break; 2223 2224 /* 2225 * Keep "m" busy because a subsequent iteration may unlock 2226 * the object. 2227 */ 2228 } 2229 if (pindex > start) { 2230 m = vm_page_lookup(object, start); 2231 while (m != NULL && m->pindex < pindex) { 2232 vm_page_xunbusy(m); 2233 m = TAILQ_NEXT(m, listq); 2234 } 2235 } 2236 return (pindex == end); 2237 } 2238 2239 /* 2240 * Routine: vm_object_coalesce 2241 * Function: Coalesces two objects backing up adjoining 2242 * regions of memory into a single object. 2243 * 2244 * returns TRUE if objects were combined. 2245 * 2246 * NOTE: Only works at the moment if the second object is NULL - 2247 * if it's not, which object do we lock first? 2248 * 2249 * Parameters: 2250 * prev_object First object to coalesce 2251 * prev_offset Offset into prev_object 2252 * prev_size Size of reference to prev_object 2253 * next_size Size of reference to the second object 2254 * reserved Indicator that extension region has 2255 * swap accounted for 2256 * 2257 * Conditions: 2258 * The object must *not* be locked. 2259 */ 2260 boolean_t 2261 vm_object_coalesce(vm_object_t prev_object, vm_ooffset_t prev_offset, 2262 vm_size_t prev_size, vm_size_t next_size, boolean_t reserved) 2263 { 2264 vm_pindex_t next_pindex; 2265 2266 if (prev_object == NULL) 2267 return (TRUE); 2268 if ((prev_object->flags & OBJ_ANON) == 0) 2269 return (FALSE); 2270 2271 VM_OBJECT_WLOCK(prev_object); 2272 /* 2273 * Try to collapse the object first. 2274 */ 2275 vm_object_collapse(prev_object); 2276 2277 /* 2278 * Can't coalesce if: . more than one reference . paged out . shadows 2279 * another object . has a copy elsewhere (any of which mean that the 2280 * pages not mapped to prev_entry may be in use anyway) 2281 */ 2282 if (prev_object->backing_object != NULL) { 2283 VM_OBJECT_WUNLOCK(prev_object); 2284 return (FALSE); 2285 } 2286 2287 prev_size >>= PAGE_SHIFT; 2288 next_size >>= PAGE_SHIFT; 2289 next_pindex = OFF_TO_IDX(prev_offset) + prev_size; 2290 2291 if (prev_object->ref_count > 1 && 2292 prev_object->size != next_pindex && 2293 (prev_object->flags & OBJ_ONEMAPPING) == 0) { 2294 VM_OBJECT_WUNLOCK(prev_object); 2295 return (FALSE); 2296 } 2297 2298 /* 2299 * Account for the charge. 2300 */ 2301 if (prev_object->cred != NULL) { 2302 /* 2303 * If prev_object was charged, then this mapping, 2304 * although not charged now, may become writable 2305 * later. Non-NULL cred in the object would prevent 2306 * swap reservation during enabling of the write 2307 * access, so reserve swap now. Failed reservation 2308 * cause allocation of the separate object for the map 2309 * entry, and swap reservation for this entry is 2310 * managed in appropriate time. 2311 */ 2312 if (!reserved && !swap_reserve_by_cred(ptoa(next_size), 2313 prev_object->cred)) { 2314 VM_OBJECT_WUNLOCK(prev_object); 2315 return (FALSE); 2316 } 2317 prev_object->charge += ptoa(next_size); 2318 } 2319 2320 /* 2321 * Remove any pages that may still be in the object from a previous 2322 * deallocation. 2323 */ 2324 if (next_pindex < prev_object->size) { 2325 vm_object_page_remove(prev_object, next_pindex, next_pindex + 2326 next_size, 0); 2327 #if 0 2328 if (prev_object->cred != NULL) { 2329 KASSERT(prev_object->charge >= 2330 ptoa(prev_object->size - next_pindex), 2331 ("object %p overcharged 1 %jx %jx", prev_object, 2332 (uintmax_t)next_pindex, (uintmax_t)next_size)); 2333 prev_object->charge -= ptoa(prev_object->size - 2334 next_pindex); 2335 } 2336 #endif 2337 } 2338 2339 /* 2340 * Extend the object if necessary. 2341 */ 2342 if (next_pindex + next_size > prev_object->size) 2343 prev_object->size = next_pindex + next_size; 2344 2345 VM_OBJECT_WUNLOCK(prev_object); 2346 return (TRUE); 2347 } 2348 2349 void 2350 vm_object_set_writeable_dirty_(vm_object_t object) 2351 { 2352 atomic_add_int(&object->generation, 1); 2353 } 2354 2355 bool 2356 vm_object_mightbedirty_(vm_object_t object) 2357 { 2358 return (object->generation != object->cleangeneration); 2359 } 2360 2361 /* 2362 * vm_object_unwire: 2363 * 2364 * For each page offset within the specified range of the given object, 2365 * find the highest-level page in the shadow chain and unwire it. A page 2366 * must exist at every page offset, and the highest-level page must be 2367 * wired. 2368 */ 2369 void 2370 vm_object_unwire(vm_object_t object, vm_ooffset_t offset, vm_size_t length, 2371 uint8_t queue) 2372 { 2373 vm_object_t tobject, t1object; 2374 vm_page_t m, tm; 2375 vm_pindex_t end_pindex, pindex, tpindex; 2376 int depth, locked_depth; 2377 2378 KASSERT((offset & PAGE_MASK) == 0, 2379 ("vm_object_unwire: offset is not page aligned")); 2380 KASSERT((length & PAGE_MASK) == 0, 2381 ("vm_object_unwire: length is not a multiple of PAGE_SIZE")); 2382 /* The wired count of a fictitious page never changes. */ 2383 if ((object->flags & OBJ_FICTITIOUS) != 0) 2384 return; 2385 pindex = OFF_TO_IDX(offset); 2386 end_pindex = pindex + atop(length); 2387 again: 2388 locked_depth = 1; 2389 VM_OBJECT_RLOCK(object); 2390 m = vm_page_find_least(object, pindex); 2391 while (pindex < end_pindex) { 2392 if (m == NULL || pindex < m->pindex) { 2393 /* 2394 * The first object in the shadow chain doesn't 2395 * contain a page at the current index. Therefore, 2396 * the page must exist in a backing object. 2397 */ 2398 tobject = object; 2399 tpindex = pindex; 2400 depth = 0; 2401 do { 2402 tpindex += 2403 OFF_TO_IDX(tobject->backing_object_offset); 2404 tobject = tobject->backing_object; 2405 KASSERT(tobject != NULL, 2406 ("vm_object_unwire: missing page")); 2407 if ((tobject->flags & OBJ_FICTITIOUS) != 0) 2408 goto next_page; 2409 depth++; 2410 if (depth == locked_depth) { 2411 locked_depth++; 2412 VM_OBJECT_RLOCK(tobject); 2413 } 2414 } while ((tm = vm_page_lookup(tobject, tpindex)) == 2415 NULL); 2416 } else { 2417 tm = m; 2418 m = TAILQ_NEXT(m, listq); 2419 } 2420 if (vm_page_trysbusy(tm) == 0) { 2421 for (tobject = object; locked_depth >= 1; 2422 locked_depth--) { 2423 t1object = tobject->backing_object; 2424 if (tm->object != tobject) 2425 VM_OBJECT_RUNLOCK(tobject); 2426 tobject = t1object; 2427 } 2428 tobject = tm->object; 2429 if (!vm_page_busy_sleep(tm, "unwbo", 2430 VM_ALLOC_IGN_SBUSY)) 2431 VM_OBJECT_RUNLOCK(tobject); 2432 goto again; 2433 } 2434 vm_page_unwire(tm, queue); 2435 vm_page_sunbusy(tm); 2436 next_page: 2437 pindex++; 2438 } 2439 /* Release the accumulated object locks. */ 2440 for (tobject = object; locked_depth >= 1; locked_depth--) { 2441 t1object = tobject->backing_object; 2442 VM_OBJECT_RUNLOCK(tobject); 2443 tobject = t1object; 2444 } 2445 } 2446 2447 /* 2448 * Return the vnode for the given object, or NULL if none exists. 2449 * For tmpfs objects, the function may return NULL if there is 2450 * no vnode allocated at the time of the call. 2451 */ 2452 struct vnode * 2453 vm_object_vnode(vm_object_t object) 2454 { 2455 struct vnode *vp; 2456 2457 VM_OBJECT_ASSERT_LOCKED(object); 2458 vm_pager_getvp(object, &vp, NULL); 2459 return (vp); 2460 } 2461 2462 /* 2463 * Busy the vm object. This prevents new pages belonging to the object from 2464 * becoming busy. Existing pages persist as busy. Callers are responsible 2465 * for checking page state before proceeding. 2466 */ 2467 void 2468 vm_object_busy(vm_object_t obj) 2469 { 2470 2471 VM_OBJECT_ASSERT_LOCKED(obj); 2472 2473 blockcount_acquire(&obj->busy, 1); 2474 /* The fence is required to order loads of page busy. */ 2475 atomic_thread_fence_acq_rel(); 2476 } 2477 2478 void 2479 vm_object_unbusy(vm_object_t obj) 2480 { 2481 2482 blockcount_release(&obj->busy, 1); 2483 } 2484 2485 void 2486 vm_object_busy_wait(vm_object_t obj, const char *wmesg) 2487 { 2488 2489 VM_OBJECT_ASSERT_UNLOCKED(obj); 2490 2491 (void)blockcount_sleep(&obj->busy, NULL, wmesg, PVM); 2492 } 2493 2494 /* 2495 * This function aims to determine if the object is mapped, 2496 * specifically, if it is referenced by a vm_map_entry. Because 2497 * objects occasionally acquire transient references that do not 2498 * represent a mapping, the method used here is inexact. However, it 2499 * has very low overhead and is good enough for the advisory 2500 * vm.vmtotal sysctl. 2501 */ 2502 bool 2503 vm_object_is_active(vm_object_t obj) 2504 { 2505 2506 return (obj->ref_count > atomic_load_int(&obj->shadow_count)); 2507 } 2508 2509 static int 2510 vm_object_list_handler(struct sysctl_req *req, bool swap_only) 2511 { 2512 struct kinfo_vmobject *kvo; 2513 char *fullpath, *freepath; 2514 struct vnode *vp; 2515 struct vattr va; 2516 vm_object_t obj; 2517 vm_page_t m; 2518 u_long sp; 2519 int count, error; 2520 2521 if (req->oldptr == NULL) { 2522 /* 2523 * If an old buffer has not been provided, generate an 2524 * estimate of the space needed for a subsequent call. 2525 */ 2526 mtx_lock(&vm_object_list_mtx); 2527 count = 0; 2528 TAILQ_FOREACH(obj, &vm_object_list, object_list) { 2529 if (obj->type == OBJT_DEAD) 2530 continue; 2531 count++; 2532 } 2533 mtx_unlock(&vm_object_list_mtx); 2534 return (SYSCTL_OUT(req, NULL, sizeof(struct kinfo_vmobject) * 2535 count * 11 / 10)); 2536 } 2537 2538 kvo = malloc(sizeof(*kvo), M_TEMP, M_WAITOK | M_ZERO); 2539 error = 0; 2540 2541 /* 2542 * VM objects are type stable and are never removed from the 2543 * list once added. This allows us to safely read obj->object_list 2544 * after reacquiring the VM object lock. 2545 */ 2546 mtx_lock(&vm_object_list_mtx); 2547 TAILQ_FOREACH(obj, &vm_object_list, object_list) { 2548 if (obj->type == OBJT_DEAD || 2549 (swap_only && (obj->flags & (OBJ_ANON | OBJ_SWAP)) == 0)) 2550 continue; 2551 VM_OBJECT_RLOCK(obj); 2552 if (obj->type == OBJT_DEAD || 2553 (swap_only && (obj->flags & (OBJ_ANON | OBJ_SWAP)) == 0)) { 2554 VM_OBJECT_RUNLOCK(obj); 2555 continue; 2556 } 2557 mtx_unlock(&vm_object_list_mtx); 2558 kvo->kvo_size = ptoa(obj->size); 2559 kvo->kvo_resident = obj->resident_page_count; 2560 kvo->kvo_ref_count = obj->ref_count; 2561 kvo->kvo_shadow_count = atomic_load_int(&obj->shadow_count); 2562 kvo->kvo_memattr = obj->memattr; 2563 kvo->kvo_active = 0; 2564 kvo->kvo_inactive = 0; 2565 if (!swap_only) { 2566 TAILQ_FOREACH(m, &obj->memq, listq) { 2567 /* 2568 * A page may belong to the object but be 2569 * dequeued and set to PQ_NONE while the 2570 * object lock is not held. This makes the 2571 * reads of m->queue below racy, and we do not 2572 * count pages set to PQ_NONE. However, this 2573 * sysctl is only meant to give an 2574 * approximation of the system anyway. 2575 */ 2576 if (m->a.queue == PQ_ACTIVE) 2577 kvo->kvo_active++; 2578 else if (m->a.queue == PQ_INACTIVE) 2579 kvo->kvo_inactive++; 2580 } 2581 } 2582 2583 kvo->kvo_vn_fileid = 0; 2584 kvo->kvo_vn_fsid = 0; 2585 kvo->kvo_vn_fsid_freebsd11 = 0; 2586 freepath = NULL; 2587 fullpath = ""; 2588 vp = NULL; 2589 kvo->kvo_type = vm_object_kvme_type(obj, swap_only ? NULL : &vp); 2590 if (vp != NULL) { 2591 vref(vp); 2592 } else if ((obj->flags & OBJ_ANON) != 0) { 2593 MPASS(kvo->kvo_type == KVME_TYPE_SWAP); 2594 kvo->kvo_me = (uintptr_t)obj; 2595 /* tmpfs objs are reported as vnodes */ 2596 kvo->kvo_backing_obj = (uintptr_t)obj->backing_object; 2597 sp = swap_pager_swapped_pages(obj); 2598 kvo->kvo_swapped = sp > UINT32_MAX ? UINT32_MAX : sp; 2599 } 2600 VM_OBJECT_RUNLOCK(obj); 2601 if (vp != NULL) { 2602 vn_fullpath(vp, &fullpath, &freepath); 2603 vn_lock(vp, LK_SHARED | LK_RETRY); 2604 if (VOP_GETATTR(vp, &va, curthread->td_ucred) == 0) { 2605 kvo->kvo_vn_fileid = va.va_fileid; 2606 kvo->kvo_vn_fsid = va.va_fsid; 2607 kvo->kvo_vn_fsid_freebsd11 = va.va_fsid; 2608 /* truncate */ 2609 } 2610 vput(vp); 2611 } 2612 2613 strlcpy(kvo->kvo_path, fullpath, sizeof(kvo->kvo_path)); 2614 if (freepath != NULL) 2615 free(freepath, M_TEMP); 2616 2617 /* Pack record size down */ 2618 kvo->kvo_structsize = offsetof(struct kinfo_vmobject, kvo_path) 2619 + strlen(kvo->kvo_path) + 1; 2620 kvo->kvo_structsize = roundup(kvo->kvo_structsize, 2621 sizeof(uint64_t)); 2622 error = SYSCTL_OUT(req, kvo, kvo->kvo_structsize); 2623 maybe_yield(); 2624 mtx_lock(&vm_object_list_mtx); 2625 if (error) 2626 break; 2627 } 2628 mtx_unlock(&vm_object_list_mtx); 2629 free(kvo, M_TEMP); 2630 return (error); 2631 } 2632 2633 static int 2634 sysctl_vm_object_list(SYSCTL_HANDLER_ARGS) 2635 { 2636 return (vm_object_list_handler(req, false)); 2637 } 2638 2639 SYSCTL_PROC(_vm, OID_AUTO, objects, CTLTYPE_STRUCT | CTLFLAG_RW | CTLFLAG_SKIP | 2640 CTLFLAG_MPSAFE, NULL, 0, sysctl_vm_object_list, "S,kinfo_vmobject", 2641 "List of VM objects"); 2642 2643 static int 2644 sysctl_vm_object_list_swap(SYSCTL_HANDLER_ARGS) 2645 { 2646 return (vm_object_list_handler(req, true)); 2647 } 2648 2649 /* 2650 * This sysctl returns list of the anonymous or swap objects. Intent 2651 * is to provide stripped optimized list useful to analyze swap use. 2652 * Since technically non-swap (default) objects participate in the 2653 * shadow chains, and are converted to swap type as needed by swap 2654 * pager, we must report them. 2655 */ 2656 SYSCTL_PROC(_vm, OID_AUTO, swap_objects, 2657 CTLTYPE_STRUCT | CTLFLAG_RW | CTLFLAG_SKIP | CTLFLAG_MPSAFE, NULL, 0, 2658 sysctl_vm_object_list_swap, "S,kinfo_vmobject", 2659 "List of swap VM objects"); 2660 2661 #include "opt_ddb.h" 2662 #ifdef DDB 2663 #include <sys/kernel.h> 2664 2665 #include <sys/cons.h> 2666 2667 #include <ddb/ddb.h> 2668 2669 static int 2670 _vm_object_in_map(vm_map_t map, vm_object_t object, vm_map_entry_t entry) 2671 { 2672 vm_map_t tmpm; 2673 vm_map_entry_t tmpe; 2674 vm_object_t obj; 2675 2676 if (map == 0) 2677 return 0; 2678 2679 if (entry == 0) { 2680 VM_MAP_ENTRY_FOREACH(tmpe, map) { 2681 if (_vm_object_in_map(map, object, tmpe)) { 2682 return 1; 2683 } 2684 } 2685 } else if (entry->eflags & MAP_ENTRY_IS_SUB_MAP) { 2686 tmpm = entry->object.sub_map; 2687 VM_MAP_ENTRY_FOREACH(tmpe, tmpm) { 2688 if (_vm_object_in_map(tmpm, object, tmpe)) { 2689 return 1; 2690 } 2691 } 2692 } else if ((obj = entry->object.vm_object) != NULL) { 2693 for (; obj; obj = obj->backing_object) 2694 if (obj == object) { 2695 return 1; 2696 } 2697 } 2698 return 0; 2699 } 2700 2701 static int 2702 vm_object_in_map(vm_object_t object) 2703 { 2704 struct proc *p; 2705 2706 /* sx_slock(&allproc_lock); */ 2707 FOREACH_PROC_IN_SYSTEM(p) { 2708 if (!p->p_vmspace /* || (p->p_flag & (P_SYSTEM|P_WEXIT)) */) 2709 continue; 2710 if (_vm_object_in_map(&p->p_vmspace->vm_map, object, 0)) { 2711 /* sx_sunlock(&allproc_lock); */ 2712 return 1; 2713 } 2714 } 2715 /* sx_sunlock(&allproc_lock); */ 2716 if (_vm_object_in_map(kernel_map, object, 0)) 2717 return 1; 2718 return 0; 2719 } 2720 2721 DB_SHOW_COMMAND_FLAGS(vmochk, vm_object_check, DB_CMD_MEMSAFE) 2722 { 2723 vm_object_t object; 2724 2725 /* 2726 * make sure that internal objs are in a map somewhere 2727 * and none have zero ref counts. 2728 */ 2729 TAILQ_FOREACH(object, &vm_object_list, object_list) { 2730 if ((object->flags & OBJ_ANON) != 0) { 2731 if (object->ref_count == 0) { 2732 db_printf("vmochk: internal obj has zero ref count: %ld\n", 2733 (long)object->size); 2734 } 2735 if (!vm_object_in_map(object)) { 2736 db_printf( 2737 "vmochk: internal obj is not in a map: " 2738 "ref: %d, size: %lu: 0x%lx, backing_object: %p\n", 2739 object->ref_count, (u_long)object->size, 2740 (u_long)object->size, 2741 (void *)object->backing_object); 2742 } 2743 } 2744 if (db_pager_quit) 2745 return; 2746 } 2747 } 2748 2749 /* 2750 * vm_object_print: [ debug ] 2751 */ 2752 DB_SHOW_COMMAND(object, vm_object_print_static) 2753 { 2754 /* XXX convert args. */ 2755 vm_object_t object = (vm_object_t)addr; 2756 boolean_t full = have_addr; 2757 2758 vm_page_t p; 2759 2760 /* XXX count is an (unused) arg. Avoid shadowing it. */ 2761 #define count was_count 2762 2763 int count; 2764 2765 if (object == NULL) 2766 return; 2767 2768 db_iprintf( 2769 "Object %p: type=%d, size=0x%jx, res=%d, ref=%d, flags=0x%x ruid %d charge %jx\n", 2770 object, (int)object->type, (uintmax_t)object->size, 2771 object->resident_page_count, object->ref_count, object->flags, 2772 object->cred ? object->cred->cr_ruid : -1, (uintmax_t)object->charge); 2773 db_iprintf(" sref=%d, backing_object(%d)=(%p)+0x%jx\n", 2774 atomic_load_int(&object->shadow_count), 2775 object->backing_object ? object->backing_object->ref_count : 0, 2776 object->backing_object, (uintmax_t)object->backing_object_offset); 2777 2778 if (!full) 2779 return; 2780 2781 db_indent += 2; 2782 count = 0; 2783 TAILQ_FOREACH(p, &object->memq, listq) { 2784 if (count == 0) 2785 db_iprintf("memory:="); 2786 else if (count == 6) { 2787 db_printf("\n"); 2788 db_iprintf(" ..."); 2789 count = 0; 2790 } else 2791 db_printf(","); 2792 count++; 2793 2794 db_printf("(off=0x%jx,page=0x%jx)", 2795 (uintmax_t)p->pindex, (uintmax_t)VM_PAGE_TO_PHYS(p)); 2796 2797 if (db_pager_quit) 2798 break; 2799 } 2800 if (count != 0) 2801 db_printf("\n"); 2802 db_indent -= 2; 2803 } 2804 2805 /* XXX. */ 2806 #undef count 2807 2808 /* XXX need this non-static entry for calling from vm_map_print. */ 2809 void 2810 vm_object_print( 2811 /* db_expr_t */ long addr, 2812 boolean_t have_addr, 2813 /* db_expr_t */ long count, 2814 char *modif) 2815 { 2816 vm_object_print_static(addr, have_addr, count, modif); 2817 } 2818 2819 DB_SHOW_COMMAND_FLAGS(vmopag, vm_object_print_pages, DB_CMD_MEMSAFE) 2820 { 2821 vm_object_t object; 2822 vm_pindex_t fidx; 2823 vm_paddr_t pa; 2824 vm_page_t m, prev_m; 2825 int rcount; 2826 2827 TAILQ_FOREACH(object, &vm_object_list, object_list) { 2828 db_printf("new object: %p\n", (void *)object); 2829 if (db_pager_quit) 2830 return; 2831 2832 rcount = 0; 2833 fidx = 0; 2834 pa = -1; 2835 TAILQ_FOREACH(m, &object->memq, listq) { 2836 if ((prev_m = TAILQ_PREV(m, pglist, listq)) != NULL && 2837 prev_m->pindex + 1 != m->pindex) { 2838 if (rcount) { 2839 db_printf(" index(%ld)run(%d)pa(0x%lx)\n", 2840 (long)fidx, rcount, (long)pa); 2841 if (db_pager_quit) 2842 return; 2843 rcount = 0; 2844 } 2845 } 2846 if (rcount && 2847 (VM_PAGE_TO_PHYS(m) == pa + rcount * PAGE_SIZE)) { 2848 ++rcount; 2849 continue; 2850 } 2851 if (rcount) { 2852 db_printf(" index(%ld)run(%d)pa(0x%lx)\n", 2853 (long)fidx, rcount, (long)pa); 2854 if (db_pager_quit) 2855 return; 2856 } 2857 fidx = m->pindex; 2858 pa = VM_PAGE_TO_PHYS(m); 2859 rcount = 1; 2860 } 2861 if (rcount) { 2862 db_printf(" index(%ld)run(%d)pa(0x%lx)\n", 2863 (long)fidx, rcount, (long)pa); 2864 if (db_pager_quit) 2865 return; 2866 } 2867 } 2868 } 2869 #endif /* DDB */ 2870