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 "opt_vm.h" 66 67 #include <sys/systm.h> 68 #include <sys/blockcount.h> 69 #include <sys/conf.h> 70 #include <sys/cpuset.h> 71 #include <sys/ipc.h> 72 #include <sys/jail.h> 73 #include <sys/limits.h> 74 #include <sys/lock.h> 75 #include <sys/mman.h> 76 #include <sys/mount.h> 77 #include <sys/kernel.h> 78 #include <sys/mutex.h> 79 #include <sys/pctrie.h> 80 #include <sys/proc.h> 81 #include <sys/refcount.h> 82 #include <sys/shm.h> 83 #include <sys/sx.h> 84 #include <sys/sysctl.h> 85 #include <sys/resourcevar.h> 86 #include <sys/refcount.h> 87 #include <sys/rwlock.h> 88 #include <sys/user.h> 89 #include <sys/vnode.h> 90 #include <sys/vmmeter.h> 91 92 #include <vm/vm.h> 93 #include <vm/vm_param.h> 94 #include <vm/pmap.h> 95 #include <vm/vm_map.h> 96 #include <vm/vm_object.h> 97 #include <vm/vm_page.h> 98 #include <vm/vm_pageout.h> 99 #include <vm/vm_pager.h> 100 #include <vm/vm_phys.h> 101 #include <vm/vm_pagequeue.h> 102 #include <vm/swap_pager.h> 103 #include <vm/vm_kern.h> 104 #include <vm/vm_extern.h> 105 #include <vm/vm_radix.h> 106 #include <vm/vm_reserv.h> 107 #include <vm/uma.h> 108 109 static int old_msync; 110 SYSCTL_INT(_vm, OID_AUTO, old_msync, CTLFLAG_RW, &old_msync, 0, 111 "Use old (insecure) msync behavior"); 112 113 static int vm_object_page_collect_flush(vm_object_t object, vm_page_t p, 114 int pagerflags, int flags, boolean_t *allclean, 115 boolean_t *eio); 116 static boolean_t vm_object_page_remove_write(vm_page_t p, int flags, 117 boolean_t *allclean); 118 static void vm_object_backing_remove(vm_object_t object); 119 120 /* 121 * Virtual memory objects maintain the actual data 122 * associated with allocated virtual memory. A given 123 * page of memory exists within exactly one object. 124 * 125 * An object is only deallocated when all "references" 126 * are given up. Only one "reference" to a given 127 * region of an object should be writeable. 128 * 129 * Associated with each object is a list of all resident 130 * memory pages belonging to that object; this list is 131 * maintained by the "vm_page" module, and locked by the object's 132 * lock. 133 * 134 * Each object also records a "pager" routine which is 135 * used to retrieve (and store) pages to the proper backing 136 * storage. In addition, objects may be backed by other 137 * objects from which they were virtual-copied. 138 * 139 * The only items within the object structure which are 140 * modified after time of creation are: 141 * reference count locked by object's lock 142 * pager routine locked by object's lock 143 * 144 */ 145 146 struct object_q vm_object_list; 147 struct mtx vm_object_list_mtx; /* lock for object list and count */ 148 149 struct vm_object kernel_object_store; 150 151 static SYSCTL_NODE(_vm_stats, OID_AUTO, object, CTLFLAG_RD | CTLFLAG_MPSAFE, 0, 152 "VM object stats"); 153 154 static COUNTER_U64_DEFINE_EARLY(object_collapses); 155 SYSCTL_COUNTER_U64(_vm_stats_object, OID_AUTO, collapses, CTLFLAG_RD, 156 &object_collapses, 157 "VM object collapses"); 158 159 static COUNTER_U64_DEFINE_EARLY(object_bypasses); 160 SYSCTL_COUNTER_U64(_vm_stats_object, OID_AUTO, bypasses, CTLFLAG_RD, 161 &object_bypasses, 162 "VM object bypasses"); 163 164 static COUNTER_U64_DEFINE_EARLY(object_collapse_waits); 165 SYSCTL_COUNTER_U64(_vm_stats_object, OID_AUTO, collapse_waits, CTLFLAG_RD, 166 &object_collapse_waits, 167 "Number of sleeps for collapse"); 168 169 static uma_zone_t obj_zone; 170 171 static int vm_object_zinit(void *mem, int size, int flags); 172 173 #ifdef INVARIANTS 174 static void vm_object_zdtor(void *mem, int size, void *arg); 175 176 static void 177 vm_object_zdtor(void *mem, int size, void *arg) 178 { 179 vm_object_t object; 180 181 object = (vm_object_t)mem; 182 KASSERT(object->ref_count == 0, 183 ("object %p ref_count = %d", object, object->ref_count)); 184 KASSERT(TAILQ_EMPTY(&object->memq), 185 ("object %p has resident pages in its memq", object)); 186 KASSERT(vm_radix_is_empty(&object->rtree), 187 ("object %p has resident pages in its trie", object)); 188 #if VM_NRESERVLEVEL > 0 189 KASSERT(LIST_EMPTY(&object->rvq), 190 ("object %p has reservations", 191 object)); 192 #endif 193 KASSERT(!vm_object_busied(object), 194 ("object %p busy = %d", object, blockcount_read(&object->busy))); 195 KASSERT(object->resident_page_count == 0, 196 ("object %p resident_page_count = %d", 197 object, object->resident_page_count)); 198 KASSERT(atomic_load_int(&object->shadow_count) == 0, 199 ("object %p shadow_count = %d", 200 object, atomic_load_int(&object->shadow_count))); 201 KASSERT(object->type == OBJT_DEAD, 202 ("object %p has non-dead type %d", 203 object, object->type)); 204 KASSERT(object->charge == 0 && object->cred == NULL, 205 ("object %p has non-zero charge %ju (%p)", 206 object, (uintmax_t)object->charge, object->cred)); 207 } 208 #endif 209 210 static int 211 vm_object_zinit(void *mem, int size, int flags) 212 { 213 vm_object_t object; 214 215 object = (vm_object_t)mem; 216 rw_init_flags(&object->lock, "vmobject", RW_DUPOK | RW_NEW); 217 218 /* These are true for any object that has been freed */ 219 object->type = OBJT_DEAD; 220 vm_radix_init(&object->rtree); 221 refcount_init(&object->ref_count, 0); 222 blockcount_init(&object->paging_in_progress); 223 blockcount_init(&object->busy); 224 object->resident_page_count = 0; 225 atomic_store_int(&object->shadow_count, 0); 226 object->flags = OBJ_DEAD; 227 228 mtx_lock(&vm_object_list_mtx); 229 TAILQ_INSERT_TAIL(&vm_object_list, object, object_list); 230 mtx_unlock(&vm_object_list_mtx); 231 return (0); 232 } 233 234 static void 235 _vm_object_allocate(objtype_t type, vm_pindex_t size, u_short flags, 236 vm_object_t object, void *handle) 237 { 238 239 TAILQ_INIT(&object->memq); 240 LIST_INIT(&object->shadow_head); 241 242 object->type = type; 243 object->flags = flags; 244 if ((flags & OBJ_SWAP) != 0) { 245 pctrie_init(&object->un_pager.swp.swp_blks); 246 object->un_pager.swp.writemappings = 0; 247 } 248 249 /* 250 * Ensure that swap_pager_swapoff() iteration over object_list 251 * sees up to date type and pctrie head if it observed 252 * non-dead object. 253 */ 254 atomic_thread_fence_rel(); 255 256 object->pg_color = 0; 257 object->size = size; 258 object->domain.dr_policy = NULL; 259 object->generation = 1; 260 object->cleangeneration = 1; 261 refcount_init(&object->ref_count, 1); 262 object->memattr = VM_MEMATTR_DEFAULT; 263 object->cred = NULL; 264 object->charge = 0; 265 object->handle = handle; 266 object->backing_object = NULL; 267 object->backing_object_offset = (vm_ooffset_t) 0; 268 #if VM_NRESERVLEVEL > 0 269 LIST_INIT(&object->rvq); 270 #endif 271 umtx_shm_object_init(object); 272 } 273 274 /* 275 * vm_object_init: 276 * 277 * Initialize the VM objects module. 278 */ 279 void 280 vm_object_init(void) 281 { 282 TAILQ_INIT(&vm_object_list); 283 mtx_init(&vm_object_list_mtx, "vm object_list", NULL, MTX_DEF); 284 285 rw_init(&kernel_object->lock, "kernel vm object"); 286 vm_radix_init(&kernel_object->rtree); 287 _vm_object_allocate(OBJT_PHYS, atop(VM_MAX_KERNEL_ADDRESS - 288 VM_MIN_KERNEL_ADDRESS), OBJ_UNMANAGED, kernel_object, NULL); 289 #if VM_NRESERVLEVEL > 0 290 kernel_object->flags |= OBJ_COLORED; 291 kernel_object->pg_color = (u_short)atop(VM_MIN_KERNEL_ADDRESS); 292 #endif 293 kernel_object->un_pager.phys.ops = &default_phys_pg_ops; 294 295 /* 296 * The lock portion of struct vm_object must be type stable due 297 * to vm_pageout_fallback_object_lock locking a vm object 298 * without holding any references to it. 299 * 300 * paging_in_progress is valid always. Lockless references to 301 * the objects may acquire pip and then check OBJ_DEAD. 302 */ 303 obj_zone = uma_zcreate("VM OBJECT", sizeof (struct vm_object), NULL, 304 #ifdef INVARIANTS 305 vm_object_zdtor, 306 #else 307 NULL, 308 #endif 309 vm_object_zinit, NULL, UMA_ALIGN_PTR, UMA_ZONE_NOFREE); 310 311 vm_radix_zinit(); 312 } 313 314 void 315 vm_object_clear_flag(vm_object_t object, u_short bits) 316 { 317 318 VM_OBJECT_ASSERT_WLOCKED(object); 319 object->flags &= ~bits; 320 } 321 322 /* 323 * Sets the default memory attribute for the specified object. Pages 324 * that are allocated to this object are by default assigned this memory 325 * attribute. 326 * 327 * Presently, this function must be called before any pages are allocated 328 * to the object. In the future, this requirement may be relaxed for 329 * "default" and "swap" objects. 330 */ 331 int 332 vm_object_set_memattr(vm_object_t object, vm_memattr_t memattr) 333 { 334 335 VM_OBJECT_ASSERT_WLOCKED(object); 336 337 if (object->type == OBJT_DEAD) 338 return (KERN_INVALID_ARGUMENT); 339 if (!TAILQ_EMPTY(&object->memq)) 340 return (KERN_FAILURE); 341 342 object->memattr = memattr; 343 return (KERN_SUCCESS); 344 } 345 346 void 347 vm_object_pip_add(vm_object_t object, short i) 348 { 349 350 if (i > 0) 351 blockcount_acquire(&object->paging_in_progress, i); 352 } 353 354 void 355 vm_object_pip_wakeup(vm_object_t object) 356 { 357 358 vm_object_pip_wakeupn(object, 1); 359 } 360 361 void 362 vm_object_pip_wakeupn(vm_object_t object, short i) 363 { 364 365 if (i > 0) 366 blockcount_release(&object->paging_in_progress, i); 367 } 368 369 /* 370 * Atomically drop the object lock and wait for pip to drain. This protects 371 * from sleep/wakeup races due to identity changes. The lock is not re-acquired 372 * on return. 373 */ 374 static void 375 vm_object_pip_sleep(vm_object_t object, const char *waitid) 376 { 377 378 (void)blockcount_sleep(&object->paging_in_progress, &object->lock, 379 waitid, PVM | PDROP); 380 } 381 382 void 383 vm_object_pip_wait(vm_object_t object, const char *waitid) 384 { 385 386 VM_OBJECT_ASSERT_WLOCKED(object); 387 388 blockcount_wait(&object->paging_in_progress, &object->lock, waitid, 389 PVM); 390 } 391 392 void 393 vm_object_pip_wait_unlocked(vm_object_t object, const char *waitid) 394 { 395 396 VM_OBJECT_ASSERT_UNLOCKED(object); 397 398 blockcount_wait(&object->paging_in_progress, NULL, waitid, PVM); 399 } 400 401 /* 402 * vm_object_allocate: 403 * 404 * Returns a new object with the given size. 405 */ 406 vm_object_t 407 vm_object_allocate(objtype_t type, vm_pindex_t size) 408 { 409 vm_object_t object; 410 u_short flags; 411 412 switch (type) { 413 case OBJT_DEAD: 414 panic("vm_object_allocate: can't create OBJT_DEAD"); 415 case OBJT_SWAP: 416 flags = OBJ_COLORED | OBJ_SWAP; 417 break; 418 case OBJT_DEVICE: 419 case OBJT_SG: 420 flags = OBJ_FICTITIOUS | OBJ_UNMANAGED; 421 break; 422 case OBJT_MGTDEVICE: 423 flags = OBJ_FICTITIOUS; 424 break; 425 case OBJT_PHYS: 426 flags = OBJ_UNMANAGED; 427 break; 428 case OBJT_VNODE: 429 flags = 0; 430 break; 431 default: 432 panic("vm_object_allocate: type %d is undefined or dynamic", 433 type); 434 } 435 object = (vm_object_t)uma_zalloc(obj_zone, M_WAITOK); 436 _vm_object_allocate(type, size, flags, object, NULL); 437 438 return (object); 439 } 440 441 vm_object_t 442 vm_object_allocate_dyn(objtype_t dyntype, vm_pindex_t size, u_short flags) 443 { 444 vm_object_t object; 445 446 MPASS(dyntype >= OBJT_FIRST_DYN /* && dyntype < nitems(pagertab) */); 447 object = (vm_object_t)uma_zalloc(obj_zone, M_WAITOK); 448 _vm_object_allocate(dyntype, size, flags, object, NULL); 449 450 return (object); 451 } 452 453 /* 454 * vm_object_allocate_anon: 455 * 456 * Returns a new default object of the given size and marked as 457 * anonymous memory for special split/collapse handling. Color 458 * to be initialized by the caller. 459 */ 460 vm_object_t 461 vm_object_allocate_anon(vm_pindex_t size, vm_object_t backing_object, 462 struct ucred *cred, vm_size_t charge) 463 { 464 vm_object_t handle, object; 465 466 if (backing_object == NULL) 467 handle = NULL; 468 else if ((backing_object->flags & OBJ_ANON) != 0) 469 handle = backing_object->handle; 470 else 471 handle = backing_object; 472 object = uma_zalloc(obj_zone, M_WAITOK); 473 _vm_object_allocate(OBJT_SWAP, size, 474 OBJ_ANON | OBJ_ONEMAPPING | OBJ_SWAP, object, handle); 475 object->cred = cred; 476 object->charge = cred != NULL ? charge : 0; 477 return (object); 478 } 479 480 static void 481 vm_object_reference_vnode(vm_object_t object) 482 { 483 u_int old; 484 485 /* 486 * vnode objects need the lock for the first reference 487 * to serialize with vnode_object_deallocate(). 488 */ 489 if (!refcount_acquire_if_gt(&object->ref_count, 0)) { 490 VM_OBJECT_RLOCK(object); 491 old = refcount_acquire(&object->ref_count); 492 if (object->type == OBJT_VNODE && old == 0) 493 vref(object->handle); 494 VM_OBJECT_RUNLOCK(object); 495 } 496 } 497 498 /* 499 * vm_object_reference: 500 * 501 * Acquires a reference to the given object. 502 */ 503 void 504 vm_object_reference(vm_object_t object) 505 { 506 507 if (object == NULL) 508 return; 509 510 if (object->type == OBJT_VNODE) 511 vm_object_reference_vnode(object); 512 else 513 refcount_acquire(&object->ref_count); 514 KASSERT((object->flags & OBJ_DEAD) == 0, 515 ("vm_object_reference: Referenced dead object.")); 516 } 517 518 /* 519 * vm_object_reference_locked: 520 * 521 * Gets another reference to the given object. 522 * 523 * The object must be locked. 524 */ 525 void 526 vm_object_reference_locked(vm_object_t object) 527 { 528 u_int old; 529 530 VM_OBJECT_ASSERT_LOCKED(object); 531 old = refcount_acquire(&object->ref_count); 532 if (object->type == OBJT_VNODE && old == 0) 533 vref(object->handle); 534 KASSERT((object->flags & OBJ_DEAD) == 0, 535 ("vm_object_reference: Referenced dead object.")); 536 } 537 538 /* 539 * Handle deallocating an object of type OBJT_VNODE. 540 */ 541 static void 542 vm_object_deallocate_vnode(vm_object_t object) 543 { 544 struct vnode *vp = (struct vnode *) object->handle; 545 bool last; 546 547 KASSERT(object->type == OBJT_VNODE, 548 ("vm_object_deallocate_vnode: not a vnode object")); 549 KASSERT(vp != NULL, ("vm_object_deallocate_vnode: missing vp")); 550 551 /* Object lock to protect handle lookup. */ 552 last = refcount_release(&object->ref_count); 553 VM_OBJECT_RUNLOCK(object); 554 555 if (!last) 556 return; 557 558 if (!umtx_shm_vnobj_persistent) 559 umtx_shm_object_terminated(object); 560 561 /* vrele may need the vnode lock. */ 562 vrele(vp); 563 } 564 565 /* 566 * We dropped a reference on an object and discovered that it had a 567 * single remaining shadow. This is a sibling of the reference we 568 * dropped. Attempt to collapse the sibling and backing object. 569 */ 570 static vm_object_t 571 vm_object_deallocate_anon(vm_object_t backing_object) 572 { 573 vm_object_t object; 574 575 /* Fetch the final shadow. */ 576 object = LIST_FIRST(&backing_object->shadow_head); 577 KASSERT(object != NULL && 578 atomic_load_int(&backing_object->shadow_count) == 1, 579 ("vm_object_anon_deallocate: ref_count: %d, shadow_count: %d", 580 backing_object->ref_count, 581 atomic_load_int(&backing_object->shadow_count))); 582 KASSERT((object->flags & OBJ_ANON) != 0, 583 ("invalid shadow object %p", object)); 584 585 if (!VM_OBJECT_TRYWLOCK(object)) { 586 /* 587 * Prevent object from disappearing since we do not have a 588 * reference. 589 */ 590 vm_object_pip_add(object, 1); 591 VM_OBJECT_WUNLOCK(backing_object); 592 VM_OBJECT_WLOCK(object); 593 vm_object_pip_wakeup(object); 594 } else 595 VM_OBJECT_WUNLOCK(backing_object); 596 597 /* 598 * Check for a collapse/terminate race with the last reference holder. 599 */ 600 if ((object->flags & (OBJ_DEAD | OBJ_COLLAPSING)) != 0 || 601 !refcount_acquire_if_not_zero(&object->ref_count)) { 602 VM_OBJECT_WUNLOCK(object); 603 return (NULL); 604 } 605 backing_object = object->backing_object; 606 if (backing_object != NULL && (backing_object->flags & OBJ_ANON) != 0) 607 vm_object_collapse(object); 608 VM_OBJECT_WUNLOCK(object); 609 610 return (object); 611 } 612 613 /* 614 * vm_object_deallocate: 615 * 616 * Release a reference to the specified object, 617 * gained either through a vm_object_allocate 618 * or a vm_object_reference call. When all references 619 * are gone, storage associated with this object 620 * may be relinquished. 621 * 622 * No object may be locked. 623 */ 624 void 625 vm_object_deallocate(vm_object_t object) 626 { 627 vm_object_t temp; 628 bool released; 629 630 while (object != NULL) { 631 /* 632 * If the reference count goes to 0 we start calling 633 * vm_object_terminate() on the object chain. A ref count 634 * of 1 may be a special case depending on the shadow count 635 * being 0 or 1. These cases require a write lock on the 636 * object. 637 */ 638 if ((object->flags & OBJ_ANON) == 0) 639 released = refcount_release_if_gt(&object->ref_count, 1); 640 else 641 released = refcount_release_if_gt(&object->ref_count, 2); 642 if (released) 643 return; 644 645 if (object->type == OBJT_VNODE) { 646 VM_OBJECT_RLOCK(object); 647 if (object->type == OBJT_VNODE) { 648 vm_object_deallocate_vnode(object); 649 return; 650 } 651 VM_OBJECT_RUNLOCK(object); 652 } 653 654 VM_OBJECT_WLOCK(object); 655 KASSERT(object->ref_count > 0, 656 ("vm_object_deallocate: object deallocated too many times: %d", 657 object->type)); 658 659 /* 660 * If this is not the final reference to an anonymous 661 * object we may need to collapse the shadow chain. 662 */ 663 if (!refcount_release(&object->ref_count)) { 664 if (object->ref_count > 1 || 665 atomic_load_int(&object->shadow_count) == 0) { 666 if ((object->flags & OBJ_ANON) != 0 && 667 object->ref_count == 1) 668 vm_object_set_flag(object, 669 OBJ_ONEMAPPING); 670 VM_OBJECT_WUNLOCK(object); 671 return; 672 } 673 674 /* Handle collapsing last ref on anonymous objects. */ 675 object = vm_object_deallocate_anon(object); 676 continue; 677 } 678 679 /* 680 * Handle the final reference to an object. We restart 681 * the loop with the backing object to avoid recursion. 682 */ 683 umtx_shm_object_terminated(object); 684 temp = object->backing_object; 685 if (temp != NULL) { 686 KASSERT(object->type == OBJT_SWAP, 687 ("shadowed tmpfs v_object 2 %p", object)); 688 vm_object_backing_remove(object); 689 } 690 691 KASSERT((object->flags & OBJ_DEAD) == 0, 692 ("vm_object_deallocate: Terminating dead object.")); 693 vm_object_set_flag(object, OBJ_DEAD); 694 vm_object_terminate(object); 695 object = temp; 696 } 697 } 698 699 void 700 vm_object_destroy(vm_object_t object) 701 { 702 uma_zfree(obj_zone, object); 703 } 704 705 static void 706 vm_object_sub_shadow(vm_object_t object) 707 { 708 KASSERT(object->shadow_count >= 1, 709 ("object %p sub_shadow count zero", object)); 710 atomic_subtract_int(&object->shadow_count, 1); 711 } 712 713 static void 714 vm_object_backing_remove_locked(vm_object_t object) 715 { 716 vm_object_t backing_object; 717 718 backing_object = object->backing_object; 719 VM_OBJECT_ASSERT_WLOCKED(object); 720 VM_OBJECT_ASSERT_WLOCKED(backing_object); 721 722 KASSERT((object->flags & OBJ_COLLAPSING) == 0, 723 ("vm_object_backing_remove: Removing collapsing object.")); 724 725 vm_object_sub_shadow(backing_object); 726 if ((object->flags & OBJ_SHADOWLIST) != 0) { 727 LIST_REMOVE(object, shadow_list); 728 vm_object_clear_flag(object, OBJ_SHADOWLIST); 729 } 730 object->backing_object = NULL; 731 } 732 733 static void 734 vm_object_backing_remove(vm_object_t object) 735 { 736 vm_object_t backing_object; 737 738 VM_OBJECT_ASSERT_WLOCKED(object); 739 740 backing_object = object->backing_object; 741 if ((object->flags & OBJ_SHADOWLIST) != 0) { 742 VM_OBJECT_WLOCK(backing_object); 743 vm_object_backing_remove_locked(object); 744 VM_OBJECT_WUNLOCK(backing_object); 745 } else { 746 object->backing_object = NULL; 747 vm_object_sub_shadow(backing_object); 748 } 749 } 750 751 static void 752 vm_object_backing_insert_locked(vm_object_t object, vm_object_t backing_object) 753 { 754 755 VM_OBJECT_ASSERT_WLOCKED(object); 756 757 atomic_add_int(&backing_object->shadow_count, 1); 758 if ((backing_object->flags & OBJ_ANON) != 0) { 759 VM_OBJECT_ASSERT_WLOCKED(backing_object); 760 LIST_INSERT_HEAD(&backing_object->shadow_head, object, 761 shadow_list); 762 vm_object_set_flag(object, OBJ_SHADOWLIST); 763 } 764 object->backing_object = backing_object; 765 } 766 767 static void 768 vm_object_backing_insert(vm_object_t object, vm_object_t backing_object) 769 { 770 771 VM_OBJECT_ASSERT_WLOCKED(object); 772 773 if ((backing_object->flags & OBJ_ANON) != 0) { 774 VM_OBJECT_WLOCK(backing_object); 775 vm_object_backing_insert_locked(object, backing_object); 776 VM_OBJECT_WUNLOCK(backing_object); 777 } else { 778 object->backing_object = backing_object; 779 atomic_add_int(&backing_object->shadow_count, 1); 780 } 781 } 782 783 /* 784 * Insert an object into a backing_object's shadow list with an additional 785 * reference to the backing_object added. 786 */ 787 static void 788 vm_object_backing_insert_ref(vm_object_t object, vm_object_t backing_object) 789 { 790 791 VM_OBJECT_ASSERT_WLOCKED(object); 792 793 if ((backing_object->flags & OBJ_ANON) != 0) { 794 VM_OBJECT_WLOCK(backing_object); 795 KASSERT((backing_object->flags & OBJ_DEAD) == 0, 796 ("shadowing dead anonymous object")); 797 vm_object_reference_locked(backing_object); 798 vm_object_backing_insert_locked(object, backing_object); 799 vm_object_clear_flag(backing_object, OBJ_ONEMAPPING); 800 VM_OBJECT_WUNLOCK(backing_object); 801 } else { 802 vm_object_reference(backing_object); 803 atomic_add_int(&backing_object->shadow_count, 1); 804 object->backing_object = backing_object; 805 } 806 } 807 808 /* 809 * Transfer a backing reference from backing_object to object. 810 */ 811 static void 812 vm_object_backing_transfer(vm_object_t object, vm_object_t backing_object) 813 { 814 vm_object_t new_backing_object; 815 816 /* 817 * Note that the reference to backing_object->backing_object 818 * moves from within backing_object to within object. 819 */ 820 vm_object_backing_remove_locked(object); 821 new_backing_object = backing_object->backing_object; 822 if (new_backing_object == NULL) 823 return; 824 if ((new_backing_object->flags & OBJ_ANON) != 0) { 825 VM_OBJECT_WLOCK(new_backing_object); 826 vm_object_backing_remove_locked(backing_object); 827 vm_object_backing_insert_locked(object, new_backing_object); 828 VM_OBJECT_WUNLOCK(new_backing_object); 829 } else { 830 /* 831 * shadow_count for new_backing_object is left 832 * unchanged, its reference provided by backing_object 833 * is replaced by object. 834 */ 835 object->backing_object = new_backing_object; 836 backing_object->backing_object = NULL; 837 } 838 } 839 840 /* 841 * Wait for a concurrent collapse to settle. 842 */ 843 static void 844 vm_object_collapse_wait(vm_object_t object) 845 { 846 847 VM_OBJECT_ASSERT_WLOCKED(object); 848 849 while ((object->flags & OBJ_COLLAPSING) != 0) { 850 vm_object_pip_wait(object, "vmcolwait"); 851 counter_u64_add(object_collapse_waits, 1); 852 } 853 } 854 855 /* 856 * Waits for a backing object to clear a pending collapse and returns 857 * it locked if it is an ANON object. 858 */ 859 static vm_object_t 860 vm_object_backing_collapse_wait(vm_object_t object) 861 { 862 vm_object_t backing_object; 863 864 VM_OBJECT_ASSERT_WLOCKED(object); 865 866 for (;;) { 867 backing_object = object->backing_object; 868 if (backing_object == NULL || 869 (backing_object->flags & OBJ_ANON) == 0) 870 return (NULL); 871 VM_OBJECT_WLOCK(backing_object); 872 if ((backing_object->flags & (OBJ_DEAD | OBJ_COLLAPSING)) == 0) 873 break; 874 VM_OBJECT_WUNLOCK(object); 875 vm_object_pip_sleep(backing_object, "vmbckwait"); 876 counter_u64_add(object_collapse_waits, 1); 877 VM_OBJECT_WLOCK(object); 878 } 879 return (backing_object); 880 } 881 882 /* 883 * vm_object_terminate_single_page removes a pageable page from the object, 884 * and removes it from the paging queues and frees it, if it is not wired. 885 * It is invoked via callback from vm_object_terminate_pages. 886 */ 887 static void 888 vm_object_terminate_single_page(vm_page_t p, void *objectv) 889 { 890 vm_object_t object __diagused = objectv; 891 892 vm_page_assert_unbusied(p); 893 KASSERT(p->object == object && 894 (p->ref_count & VPRC_OBJREF) != 0, 895 ("%s: page %p is inconsistent", __func__, p)); 896 p->object = NULL; 897 if (vm_page_drop(p, VPRC_OBJREF) == VPRC_OBJREF) { 898 KASSERT((object->flags & OBJ_UNMANAGED) != 0 || 899 vm_page_astate_load(p).queue != PQ_NONE, 900 ("%s: page %p does not belong to a queue", __func__, p)); 901 VM_CNT_INC(v_pfree); 902 vm_page_free(p); 903 } 904 } 905 906 /* 907 * vm_object_terminate_pages removes any remaining pageable pages 908 * from the object and resets the object to an empty state. 909 */ 910 static void 911 vm_object_terminate_pages(vm_object_t object) 912 { 913 VM_OBJECT_ASSERT_WLOCKED(object); 914 915 /* 916 * If the object contained any pages, then reset it to an empty state. 917 * Rather than incrementally removing each page from the object, the 918 * page and object are reset to any empty state. 919 */ 920 if (object->resident_page_count == 0) 921 return; 922 923 vm_radix_reclaim_callback(&object->rtree, 924 vm_object_terminate_single_page, object); 925 TAILQ_INIT(&object->memq); 926 object->resident_page_count = 0; 927 if (object->type == OBJT_VNODE) 928 vdrop(object->handle); 929 } 930 931 /* 932 * vm_object_terminate actually destroys the specified object, freeing 933 * up all previously used resources. 934 * 935 * The object must be locked. 936 * This routine may block. 937 */ 938 void 939 vm_object_terminate(vm_object_t object) 940 { 941 942 VM_OBJECT_ASSERT_WLOCKED(object); 943 KASSERT((object->flags & OBJ_DEAD) != 0, 944 ("terminating non-dead obj %p", object)); 945 KASSERT((object->flags & OBJ_COLLAPSING) == 0, 946 ("terminating collapsing obj %p", object)); 947 KASSERT(object->backing_object == NULL, 948 ("terminating shadow obj %p", object)); 949 950 /* 951 * Wait for the pageout daemon and other current users to be 952 * done with the object. Note that new paging_in_progress 953 * users can come after this wait, but they must check 954 * OBJ_DEAD flag set (without unlocking the object), and avoid 955 * the object being terminated. 956 */ 957 vm_object_pip_wait(object, "objtrm"); 958 959 KASSERT(object->ref_count == 0, 960 ("vm_object_terminate: object with references, ref_count=%d", 961 object->ref_count)); 962 963 if ((object->flags & OBJ_PG_DTOR) == 0) 964 vm_object_terminate_pages(object); 965 966 #if VM_NRESERVLEVEL > 0 967 if (__predict_false(!LIST_EMPTY(&object->rvq))) 968 vm_reserv_break_all(object); 969 #endif 970 971 KASSERT(object->cred == NULL || (object->flags & OBJ_SWAP) != 0, 972 ("%s: non-swap obj %p has cred", __func__, object)); 973 974 /* 975 * Let the pager know object is dead. 976 */ 977 vm_pager_deallocate(object); 978 VM_OBJECT_WUNLOCK(object); 979 980 vm_object_destroy(object); 981 } 982 983 /* 984 * Make the page read-only so that we can clear the object flags. However, if 985 * this is a nosync mmap then the object is likely to stay dirty so do not 986 * mess with the page and do not clear the object flags. Returns TRUE if the 987 * page should be flushed, and FALSE otherwise. 988 */ 989 static boolean_t 990 vm_object_page_remove_write(vm_page_t p, int flags, boolean_t *allclean) 991 { 992 993 vm_page_assert_busied(p); 994 995 /* 996 * If we have been asked to skip nosync pages and this is a 997 * nosync page, skip it. Note that the object flags were not 998 * cleared in this case so we do not have to set them. 999 */ 1000 if ((flags & OBJPC_NOSYNC) != 0 && (p->a.flags & PGA_NOSYNC) != 0) { 1001 *allclean = FALSE; 1002 return (FALSE); 1003 } else { 1004 pmap_remove_write(p); 1005 return (p->dirty != 0); 1006 } 1007 } 1008 1009 /* 1010 * vm_object_page_clean 1011 * 1012 * Clean all dirty pages in the specified range of object. Leaves page 1013 * on whatever queue it is currently on. If NOSYNC is set then do not 1014 * write out pages with PGA_NOSYNC set (originally comes from MAP_NOSYNC), 1015 * leaving the object dirty. 1016 * 1017 * For swap objects backing tmpfs regular files, do not flush anything, 1018 * but remove write protection on the mapped pages to update mtime through 1019 * mmaped writes. 1020 * 1021 * When stuffing pages asynchronously, allow clustering. XXX we need a 1022 * synchronous clustering mode implementation. 1023 * 1024 * Odd semantics: if start == end, we clean everything. 1025 * 1026 * The object must be locked. 1027 * 1028 * Returns FALSE if some page from the range was not written, as 1029 * reported by the pager, and TRUE otherwise. 1030 */ 1031 boolean_t 1032 vm_object_page_clean(vm_object_t object, vm_ooffset_t start, vm_ooffset_t end, 1033 int flags) 1034 { 1035 vm_page_t np, p; 1036 vm_pindex_t pi, tend, tstart; 1037 int curgeneration, n, pagerflags; 1038 boolean_t eio, res, allclean; 1039 1040 VM_OBJECT_ASSERT_WLOCKED(object); 1041 1042 if (!vm_object_mightbedirty(object) || object->resident_page_count == 0) 1043 return (TRUE); 1044 1045 pagerflags = (flags & (OBJPC_SYNC | OBJPC_INVAL)) != 0 ? 1046 VM_PAGER_PUT_SYNC : VM_PAGER_CLUSTER_OK; 1047 pagerflags |= (flags & OBJPC_INVAL) != 0 ? VM_PAGER_PUT_INVAL : 0; 1048 1049 tstart = OFF_TO_IDX(start); 1050 tend = (end == 0) ? object->size : OFF_TO_IDX(end + PAGE_MASK); 1051 allclean = tstart == 0 && tend >= object->size; 1052 res = TRUE; 1053 1054 rescan: 1055 curgeneration = object->generation; 1056 1057 for (p = vm_page_find_least(object, tstart); p != NULL; p = np) { 1058 pi = p->pindex; 1059 if (pi >= tend) 1060 break; 1061 np = TAILQ_NEXT(p, listq); 1062 if (vm_page_none_valid(p)) 1063 continue; 1064 if (vm_page_busy_acquire(p, VM_ALLOC_WAITFAIL) == 0) { 1065 if (object->generation != curgeneration && 1066 (flags & OBJPC_SYNC) != 0) 1067 goto rescan; 1068 np = vm_page_find_least(object, pi); 1069 continue; 1070 } 1071 if (!vm_object_page_remove_write(p, flags, &allclean)) { 1072 vm_page_xunbusy(p); 1073 continue; 1074 } 1075 if (object->type == OBJT_VNODE) { 1076 n = vm_object_page_collect_flush(object, p, pagerflags, 1077 flags, &allclean, &eio); 1078 if (eio) { 1079 res = FALSE; 1080 allclean = FALSE; 1081 } 1082 if (object->generation != curgeneration && 1083 (flags & OBJPC_SYNC) != 0) 1084 goto rescan; 1085 1086 /* 1087 * If the VOP_PUTPAGES() did a truncated write, so 1088 * that even the first page of the run is not fully 1089 * written, vm_pageout_flush() returns 0 as the run 1090 * length. Since the condition that caused truncated 1091 * write may be permanent, e.g. exhausted free space, 1092 * accepting n == 0 would cause an infinite loop. 1093 * 1094 * Forwarding the iterator leaves the unwritten page 1095 * behind, but there is not much we can do there if 1096 * filesystem refuses to write it. 1097 */ 1098 if (n == 0) { 1099 n = 1; 1100 allclean = FALSE; 1101 } 1102 } else { 1103 n = 1; 1104 vm_page_xunbusy(p); 1105 } 1106 np = vm_page_find_least(object, pi + n); 1107 } 1108 #if 0 1109 VOP_FSYNC(vp, (pagerflags & VM_PAGER_PUT_SYNC) ? MNT_WAIT : 0); 1110 #endif 1111 1112 /* 1113 * Leave updating cleangeneration for tmpfs objects to tmpfs 1114 * scan. It needs to update mtime, which happens for other 1115 * filesystems during page writeouts. 1116 */ 1117 if (allclean && object->type == OBJT_VNODE) 1118 object->cleangeneration = curgeneration; 1119 return (res); 1120 } 1121 1122 static int 1123 vm_object_page_collect_flush(vm_object_t object, vm_page_t p, int pagerflags, 1124 int flags, boolean_t *allclean, boolean_t *eio) 1125 { 1126 vm_page_t ma[2 * vm_pageout_page_count - 1], tp; 1127 int base, count, runlen; 1128 1129 vm_page_lock_assert(p, MA_NOTOWNED); 1130 vm_page_assert_xbusied(p); 1131 VM_OBJECT_ASSERT_WLOCKED(object); 1132 base = nitems(ma) / 2; 1133 ma[base] = p; 1134 for (count = 1, 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 ma[base + count] = tp; 1143 } 1144 1145 for (tp = p; count < vm_pageout_page_count; count++) { 1146 tp = vm_page_prev(tp); 1147 if (tp == NULL || vm_page_tryxbusy(tp) == 0) 1148 break; 1149 if (!vm_object_page_remove_write(tp, flags, allclean)) { 1150 vm_page_xunbusy(tp); 1151 break; 1152 } 1153 ma[--base] = tp; 1154 } 1155 1156 vm_pageout_flush(&ma[base], count, pagerflags, nitems(ma) / 2 - base, 1157 &runlen, eio); 1158 return (runlen); 1159 } 1160 1161 /* 1162 * Note that there is absolutely no sense in writing out 1163 * anonymous objects, so we track down the vnode object 1164 * to write out. 1165 * We invalidate (remove) all pages from the address space 1166 * for semantic correctness. 1167 * 1168 * If the backing object is a device object with unmanaged pages, then any 1169 * mappings to the specified range of pages must be removed before this 1170 * function is called. 1171 * 1172 * Note: certain anonymous maps, such as MAP_NOSYNC maps, 1173 * may start out with a NULL object. 1174 */ 1175 boolean_t 1176 vm_object_sync(vm_object_t object, vm_ooffset_t offset, vm_size_t size, 1177 boolean_t syncio, boolean_t invalidate) 1178 { 1179 vm_object_t backing_object; 1180 struct vnode *vp; 1181 struct mount *mp; 1182 int error, flags, fsync_after; 1183 boolean_t res; 1184 1185 if (object == NULL) 1186 return (TRUE); 1187 res = TRUE; 1188 error = 0; 1189 VM_OBJECT_WLOCK(object); 1190 while ((backing_object = object->backing_object) != NULL) { 1191 VM_OBJECT_WLOCK(backing_object); 1192 offset += object->backing_object_offset; 1193 VM_OBJECT_WUNLOCK(object); 1194 object = backing_object; 1195 if (object->size < OFF_TO_IDX(offset + size)) 1196 size = IDX_TO_OFF(object->size) - offset; 1197 } 1198 /* 1199 * Flush pages if writing is allowed, invalidate them 1200 * if invalidation requested. Pages undergoing I/O 1201 * will be ignored by vm_object_page_remove(). 1202 * 1203 * We cannot lock the vnode and then wait for paging 1204 * to complete without deadlocking against vm_fault. 1205 * Instead we simply call vm_object_page_remove() and 1206 * allow it to block internally on a page-by-page 1207 * basis when it encounters pages undergoing async 1208 * I/O. 1209 */ 1210 if (object->type == OBJT_VNODE && 1211 vm_object_mightbedirty(object) != 0 && 1212 ((vp = object->handle)->v_vflag & VV_NOSYNC) == 0) { 1213 VM_OBJECT_WUNLOCK(object); 1214 (void)vn_start_write(vp, &mp, V_WAIT); 1215 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY); 1216 if (syncio && !invalidate && offset == 0 && 1217 atop(size) == object->size) { 1218 /* 1219 * If syncing the whole mapping of the file, 1220 * it is faster to schedule all the writes in 1221 * async mode, also allowing the clustering, 1222 * and then wait for i/o to complete. 1223 */ 1224 flags = 0; 1225 fsync_after = TRUE; 1226 } else { 1227 flags = (syncio || invalidate) ? OBJPC_SYNC : 0; 1228 flags |= invalidate ? (OBJPC_SYNC | OBJPC_INVAL) : 0; 1229 fsync_after = FALSE; 1230 } 1231 VM_OBJECT_WLOCK(object); 1232 res = vm_object_page_clean(object, offset, offset + size, 1233 flags); 1234 VM_OBJECT_WUNLOCK(object); 1235 if (fsync_after) { 1236 for (;;) { 1237 error = VOP_FSYNC(vp, MNT_WAIT, curthread); 1238 if (error != ERELOOKUP) 1239 break; 1240 1241 /* 1242 * Allow SU/bufdaemon to handle more 1243 * dependencies in the meantime. 1244 */ 1245 VOP_UNLOCK(vp); 1246 vn_finished_write(mp); 1247 1248 (void)vn_start_write(vp, &mp, V_WAIT); 1249 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY); 1250 } 1251 } 1252 VOP_UNLOCK(vp); 1253 vn_finished_write(mp); 1254 if (error != 0) 1255 res = FALSE; 1256 VM_OBJECT_WLOCK(object); 1257 } 1258 if ((object->type == OBJT_VNODE || 1259 object->type == OBJT_DEVICE) && invalidate) { 1260 if (object->type == OBJT_DEVICE) 1261 /* 1262 * The option OBJPR_NOTMAPPED must be passed here 1263 * because vm_object_page_remove() cannot remove 1264 * unmanaged mappings. 1265 */ 1266 flags = OBJPR_NOTMAPPED; 1267 else if (old_msync) 1268 flags = 0; 1269 else 1270 flags = OBJPR_CLEANONLY; 1271 vm_object_page_remove(object, OFF_TO_IDX(offset), 1272 OFF_TO_IDX(offset + size + PAGE_MASK), flags); 1273 } 1274 VM_OBJECT_WUNLOCK(object); 1275 return (res); 1276 } 1277 1278 /* 1279 * Determine whether the given advice can be applied to the object. Advice is 1280 * not applied to unmanaged pages since they never belong to page queues, and 1281 * since MADV_FREE is destructive, it can apply only to anonymous pages that 1282 * have been mapped at most once. 1283 */ 1284 static bool 1285 vm_object_advice_applies(vm_object_t object, int advice) 1286 { 1287 1288 if ((object->flags & OBJ_UNMANAGED) != 0) 1289 return (false); 1290 if (advice != MADV_FREE) 1291 return (true); 1292 return ((object->flags & (OBJ_ONEMAPPING | OBJ_ANON)) == 1293 (OBJ_ONEMAPPING | OBJ_ANON)); 1294 } 1295 1296 static void 1297 vm_object_madvise_freespace(vm_object_t object, int advice, vm_pindex_t pindex, 1298 vm_size_t size) 1299 { 1300 1301 if (advice == MADV_FREE) 1302 vm_pager_freespace(object, pindex, size); 1303 } 1304 1305 /* 1306 * vm_object_madvise: 1307 * 1308 * Implements the madvise function at the object/page level. 1309 * 1310 * MADV_WILLNEED (any object) 1311 * 1312 * Activate the specified pages if they are resident. 1313 * 1314 * MADV_DONTNEED (any object) 1315 * 1316 * Deactivate the specified pages if they are resident. 1317 * 1318 * MADV_FREE (OBJT_SWAP objects, OBJ_ONEMAPPING only) 1319 * 1320 * Deactivate and clean the specified pages if they are 1321 * resident. This permits the process to reuse the pages 1322 * without faulting or the kernel to reclaim the pages 1323 * without I/O. 1324 */ 1325 void 1326 vm_object_madvise(vm_object_t object, vm_pindex_t pindex, vm_pindex_t end, 1327 int advice) 1328 { 1329 vm_pindex_t tpindex; 1330 vm_object_t backing_object, tobject; 1331 vm_page_t m, tm; 1332 1333 if (object == NULL) 1334 return; 1335 1336 relookup: 1337 VM_OBJECT_WLOCK(object); 1338 if (!vm_object_advice_applies(object, advice)) { 1339 VM_OBJECT_WUNLOCK(object); 1340 return; 1341 } 1342 for (m = vm_page_find_least(object, pindex); pindex < end; pindex++) { 1343 tobject = object; 1344 1345 /* 1346 * If the next page isn't resident in the top-level object, we 1347 * need to search the shadow chain. When applying MADV_FREE, we 1348 * take care to release any swap space used to store 1349 * non-resident pages. 1350 */ 1351 if (m == NULL || pindex < m->pindex) { 1352 /* 1353 * Optimize a common case: if the top-level object has 1354 * no backing object, we can skip over the non-resident 1355 * range in constant time. 1356 */ 1357 if (object->backing_object == NULL) { 1358 tpindex = (m != NULL && m->pindex < end) ? 1359 m->pindex : end; 1360 vm_object_madvise_freespace(object, advice, 1361 pindex, tpindex - pindex); 1362 if ((pindex = tpindex) == end) 1363 break; 1364 goto next_page; 1365 } 1366 1367 tpindex = pindex; 1368 do { 1369 vm_object_madvise_freespace(tobject, advice, 1370 tpindex, 1); 1371 /* 1372 * Prepare to search the next object in the 1373 * chain. 1374 */ 1375 backing_object = tobject->backing_object; 1376 if (backing_object == NULL) 1377 goto next_pindex; 1378 VM_OBJECT_WLOCK(backing_object); 1379 tpindex += 1380 OFF_TO_IDX(tobject->backing_object_offset); 1381 if (tobject != object) 1382 VM_OBJECT_WUNLOCK(tobject); 1383 tobject = backing_object; 1384 if (!vm_object_advice_applies(tobject, advice)) 1385 goto next_pindex; 1386 } while ((tm = vm_page_lookup(tobject, tpindex)) == 1387 NULL); 1388 } else { 1389 next_page: 1390 tm = m; 1391 m = TAILQ_NEXT(m, listq); 1392 } 1393 1394 /* 1395 * If the page is not in a normal state, skip it. The page 1396 * can not be invalidated while the object lock is held. 1397 */ 1398 if (!vm_page_all_valid(tm) || vm_page_wired(tm)) 1399 goto next_pindex; 1400 KASSERT((tm->flags & PG_FICTITIOUS) == 0, 1401 ("vm_object_madvise: page %p is fictitious", tm)); 1402 KASSERT((tm->oflags & VPO_UNMANAGED) == 0, 1403 ("vm_object_madvise: page %p is not managed", tm)); 1404 if (vm_page_tryxbusy(tm) == 0) { 1405 if (object != tobject) 1406 VM_OBJECT_WUNLOCK(object); 1407 if (advice == MADV_WILLNEED) { 1408 /* 1409 * Reference the page before unlocking and 1410 * sleeping so that the page daemon is less 1411 * likely to reclaim it. 1412 */ 1413 vm_page_aflag_set(tm, PGA_REFERENCED); 1414 } 1415 if (!vm_page_busy_sleep(tm, "madvpo", 0)) 1416 VM_OBJECT_WUNLOCK(tobject); 1417 goto relookup; 1418 } 1419 vm_page_advise(tm, advice); 1420 vm_page_xunbusy(tm); 1421 vm_object_madvise_freespace(tobject, advice, tm->pindex, 1); 1422 next_pindex: 1423 if (tobject != object) 1424 VM_OBJECT_WUNLOCK(tobject); 1425 } 1426 VM_OBJECT_WUNLOCK(object); 1427 } 1428 1429 /* 1430 * vm_object_shadow: 1431 * 1432 * Create a new object which is backed by the 1433 * specified existing object range. The source 1434 * object reference is deallocated. 1435 * 1436 * The new object and offset into that object 1437 * are returned in the source parameters. 1438 */ 1439 void 1440 vm_object_shadow(vm_object_t *object, vm_ooffset_t *offset, vm_size_t length, 1441 struct ucred *cred, bool shared) 1442 { 1443 vm_object_t source; 1444 vm_object_t result; 1445 1446 source = *object; 1447 1448 /* 1449 * Don't create the new object if the old object isn't shared. 1450 * 1451 * If we hold the only reference we can guarantee that it won't 1452 * increase while we have the map locked. Otherwise the race is 1453 * harmless and we will end up with an extra shadow object that 1454 * will be collapsed later. 1455 */ 1456 if (source != NULL && source->ref_count == 1 && 1457 (source->flags & OBJ_ANON) != 0) 1458 return; 1459 1460 /* 1461 * Allocate a new object with the given length. 1462 */ 1463 result = vm_object_allocate_anon(atop(length), source, cred, length); 1464 1465 /* 1466 * Store the offset into the source object, and fix up the offset into 1467 * the new object. 1468 */ 1469 result->backing_object_offset = *offset; 1470 1471 if (shared || source != NULL) { 1472 VM_OBJECT_WLOCK(result); 1473 1474 /* 1475 * The new object shadows the source object, adding a 1476 * reference to it. Our caller changes his reference 1477 * to point to the new object, removing a reference to 1478 * the source object. Net result: no change of 1479 * reference count, unless the caller needs to add one 1480 * more reference due to forking a shared map entry. 1481 */ 1482 if (shared) { 1483 vm_object_reference_locked(result); 1484 vm_object_clear_flag(result, OBJ_ONEMAPPING); 1485 } 1486 1487 /* 1488 * Try to optimize the result object's page color when 1489 * shadowing in order to maintain page coloring 1490 * consistency in the combined shadowed object. 1491 */ 1492 if (source != NULL) { 1493 vm_object_backing_insert(result, source); 1494 result->domain = source->domain; 1495 #if VM_NRESERVLEVEL > 0 1496 vm_object_set_flag(result, 1497 (source->flags & OBJ_COLORED)); 1498 result->pg_color = (source->pg_color + 1499 OFF_TO_IDX(*offset)) & ((1 << (VM_NFREEORDER - 1500 1)) - 1); 1501 #endif 1502 } 1503 VM_OBJECT_WUNLOCK(result); 1504 } 1505 1506 /* 1507 * Return the new things 1508 */ 1509 *offset = 0; 1510 *object = result; 1511 } 1512 1513 /* 1514 * vm_object_split: 1515 * 1516 * Split the pages in a map entry into a new object. This affords 1517 * easier removal of unused pages, and keeps object inheritance from 1518 * being a negative impact on memory usage. 1519 */ 1520 void 1521 vm_object_split(vm_map_entry_t entry) 1522 { 1523 struct pctrie_iter pages; 1524 vm_page_t m; 1525 vm_object_t orig_object, new_object, backing_object; 1526 vm_pindex_t offidxstart; 1527 vm_size_t size; 1528 1529 orig_object = entry->object.vm_object; 1530 KASSERT((orig_object->flags & OBJ_ONEMAPPING) != 0, 1531 ("vm_object_split: Splitting object with multiple mappings.")); 1532 if ((orig_object->flags & OBJ_ANON) == 0) 1533 return; 1534 if (orig_object->ref_count <= 1) 1535 return; 1536 VM_OBJECT_WUNLOCK(orig_object); 1537 1538 offidxstart = OFF_TO_IDX(entry->offset); 1539 size = atop(entry->end - entry->start); 1540 1541 new_object = vm_object_allocate_anon(size, orig_object, 1542 orig_object->cred, ptoa(size)); 1543 1544 /* 1545 * We must wait for the orig_object to complete any in-progress 1546 * collapse so that the swap blocks are stable below. The 1547 * additional reference on backing_object by new object will 1548 * prevent further collapse operations until split completes. 1549 */ 1550 VM_OBJECT_WLOCK(orig_object); 1551 vm_object_collapse_wait(orig_object); 1552 1553 /* 1554 * At this point, the new object is still private, so the order in 1555 * which the original and new objects are locked does not matter. 1556 */ 1557 VM_OBJECT_WLOCK(new_object); 1558 new_object->domain = orig_object->domain; 1559 backing_object = orig_object->backing_object; 1560 if (backing_object != NULL) { 1561 vm_object_backing_insert_ref(new_object, backing_object); 1562 new_object->backing_object_offset = 1563 orig_object->backing_object_offset + entry->offset; 1564 } 1565 if (orig_object->cred != NULL) { 1566 crhold(orig_object->cred); 1567 KASSERT(orig_object->charge >= ptoa(size), 1568 ("orig_object->charge < 0")); 1569 orig_object->charge -= ptoa(size); 1570 } 1571 1572 /* 1573 * Mark the split operation so that swap_pager_getpages() knows 1574 * that the object is in transition. 1575 */ 1576 vm_object_set_flag(orig_object, OBJ_SPLIT); 1577 vm_page_iter_limit_init(&pages, orig_object, offidxstart + size); 1578 retry: 1579 pctrie_iter_reset(&pages); 1580 for (m = vm_page_iter_lookup_ge(&pages, offidxstart); m != NULL; 1581 m = vm_radix_iter_step(&pages)) { 1582 /* 1583 * We must wait for pending I/O to complete before we can 1584 * rename the page. 1585 * 1586 * We do not have to VM_PROT_NONE the page as mappings should 1587 * not be changed by this operation. 1588 */ 1589 if (vm_page_tryxbusy(m) == 0) { 1590 VM_OBJECT_WUNLOCK(new_object); 1591 if (vm_page_busy_sleep(m, "spltwt", 0)) 1592 VM_OBJECT_WLOCK(orig_object); 1593 VM_OBJECT_WLOCK(new_object); 1594 goto retry; 1595 } 1596 1597 /* 1598 * The page was left invalid. Likely placed there by 1599 * an incomplete fault. Just remove and ignore. 1600 */ 1601 if (vm_page_none_valid(m)) { 1602 if (vm_page_iter_remove(&pages, m)) 1603 vm_page_free(m); 1604 continue; 1605 } 1606 1607 /* vm_page_iter_rename() will dirty the page. */ 1608 if (!vm_page_iter_rename(&pages, m, new_object, m->pindex - 1609 offidxstart)) { 1610 vm_page_xunbusy(m); 1611 VM_OBJECT_WUNLOCK(new_object); 1612 VM_OBJECT_WUNLOCK(orig_object); 1613 vm_radix_wait(); 1614 VM_OBJECT_WLOCK(orig_object); 1615 VM_OBJECT_WLOCK(new_object); 1616 goto retry; 1617 } 1618 1619 #if VM_NRESERVLEVEL > 0 1620 /* 1621 * If some of the reservation's allocated pages remain with 1622 * the original object, then transferring the reservation to 1623 * the new object is neither particularly beneficial nor 1624 * particularly harmful as compared to leaving the reservation 1625 * with the original object. If, however, all of the 1626 * reservation's allocated pages are transferred to the new 1627 * object, then transferring the reservation is typically 1628 * beneficial. Determining which of these two cases applies 1629 * would be more costly than unconditionally renaming the 1630 * reservation. 1631 */ 1632 vm_reserv_rename(m, new_object, orig_object, offidxstart); 1633 #endif 1634 } 1635 1636 /* 1637 * swap_pager_copy() can sleep, in which case the orig_object's 1638 * and new_object's locks are released and reacquired. 1639 */ 1640 swap_pager_copy(orig_object, new_object, offidxstart, 0); 1641 1642 TAILQ_FOREACH(m, &new_object->memq, listq) 1643 vm_page_xunbusy(m); 1644 1645 vm_object_clear_flag(orig_object, OBJ_SPLIT); 1646 VM_OBJECT_WUNLOCK(orig_object); 1647 VM_OBJECT_WUNLOCK(new_object); 1648 entry->object.vm_object = new_object; 1649 entry->offset = 0LL; 1650 vm_object_deallocate(orig_object); 1651 VM_OBJECT_WLOCK(new_object); 1652 } 1653 1654 static vm_page_t 1655 vm_object_collapse_scan_wait(struct pctrie_iter *pages, vm_object_t object, 1656 vm_page_t p) 1657 { 1658 vm_object_t backing_object; 1659 1660 VM_OBJECT_ASSERT_WLOCKED(object); 1661 backing_object = object->backing_object; 1662 VM_OBJECT_ASSERT_WLOCKED(backing_object); 1663 1664 KASSERT(p == NULL || p->object == object || p->object == backing_object, 1665 ("invalid ownership %p %p %p", p, object, backing_object)); 1666 /* The page is only NULL when rename fails. */ 1667 if (p == NULL) { 1668 VM_OBJECT_WUNLOCK(object); 1669 VM_OBJECT_WUNLOCK(backing_object); 1670 vm_radix_wait(); 1671 VM_OBJECT_WLOCK(object); 1672 } else if (p->object == object) { 1673 VM_OBJECT_WUNLOCK(backing_object); 1674 if (vm_page_busy_sleep(p, "vmocol", 0)) 1675 VM_OBJECT_WLOCK(object); 1676 } else { 1677 VM_OBJECT_WUNLOCK(object); 1678 if (!vm_page_busy_sleep(p, "vmocol", 0)) 1679 VM_OBJECT_WUNLOCK(backing_object); 1680 VM_OBJECT_WLOCK(object); 1681 } 1682 VM_OBJECT_WLOCK(backing_object); 1683 vm_page_iter_init(pages, backing_object); 1684 return (vm_page_iter_lookup_ge(pages, 0)); 1685 } 1686 1687 static void 1688 vm_object_collapse_scan(vm_object_t object) 1689 { 1690 struct pctrie_iter pages; 1691 vm_object_t backing_object; 1692 vm_page_t next, p, pp; 1693 vm_pindex_t backing_offset_index, new_pindex; 1694 1695 VM_OBJECT_ASSERT_WLOCKED(object); 1696 VM_OBJECT_ASSERT_WLOCKED(object->backing_object); 1697 1698 backing_object = object->backing_object; 1699 backing_offset_index = OFF_TO_IDX(object->backing_object_offset); 1700 1701 /* 1702 * Our scan 1703 */ 1704 vm_page_iter_init(&pages, backing_object); 1705 for (p = vm_page_iter_lookup_ge(&pages, 0); p != NULL; p = next) { 1706 next = TAILQ_NEXT(p, listq); 1707 new_pindex = p->pindex - backing_offset_index; 1708 1709 /* 1710 * Check for busy page 1711 */ 1712 if (vm_page_tryxbusy(p) == 0) { 1713 next = vm_object_collapse_scan_wait(&pages, object, p); 1714 continue; 1715 } 1716 1717 KASSERT(object->backing_object == backing_object, 1718 ("vm_object_collapse_scan: backing object mismatch %p != %p", 1719 object->backing_object, backing_object)); 1720 KASSERT(p->object == backing_object, 1721 ("vm_object_collapse_scan: object mismatch %p != %p", 1722 p->object, backing_object)); 1723 1724 if (p->pindex < backing_offset_index || 1725 new_pindex >= object->size) { 1726 vm_pager_freespace(backing_object, p->pindex, 1); 1727 1728 KASSERT(!pmap_page_is_mapped(p), 1729 ("freeing mapped page %p", p)); 1730 if (vm_page_iter_remove(&pages, p)) 1731 vm_page_free(p); 1732 next = vm_radix_iter_step(&pages); 1733 continue; 1734 } 1735 1736 if (!vm_page_all_valid(p)) { 1737 KASSERT(!pmap_page_is_mapped(p), 1738 ("freeing mapped page %p", p)); 1739 if (vm_page_iter_remove(&pages, p)) 1740 vm_page_free(p); 1741 next = vm_radix_iter_step(&pages); 1742 continue; 1743 } 1744 1745 pp = vm_page_lookup(object, new_pindex); 1746 if (pp != NULL && vm_page_tryxbusy(pp) == 0) { 1747 vm_page_xunbusy(p); 1748 /* 1749 * The page in the parent is busy and possibly not 1750 * (yet) valid. Until its state is finalized by the 1751 * busy bit owner, we can't tell whether it shadows the 1752 * original page. 1753 */ 1754 next = vm_object_collapse_scan_wait(&pages, object, pp); 1755 continue; 1756 } 1757 1758 if (pp != NULL && vm_page_none_valid(pp)) { 1759 /* 1760 * The page was invalid in the parent. Likely placed 1761 * there by an incomplete fault. Just remove and 1762 * ignore. p can replace it. 1763 */ 1764 if (vm_page_remove(pp)) 1765 vm_page_free(pp); 1766 pp = NULL; 1767 } 1768 1769 if (pp != NULL || vm_pager_has_page(object, new_pindex, NULL, 1770 NULL)) { 1771 /* 1772 * The page already exists in the parent OR swap exists 1773 * for this location in the parent. Leave the parent's 1774 * page alone. Destroy the original page from the 1775 * backing object. 1776 */ 1777 vm_pager_freespace(backing_object, p->pindex, 1); 1778 KASSERT(!pmap_page_is_mapped(p), 1779 ("freeing mapped page %p", p)); 1780 if (pp != NULL) 1781 vm_page_xunbusy(pp); 1782 if (vm_page_iter_remove(&pages, p)) 1783 vm_page_free(p); 1784 next = vm_radix_iter_step(&pages); 1785 continue; 1786 } 1787 1788 /* 1789 * Page does not exist in parent, rename the page from the 1790 * backing object to the main object. 1791 * 1792 * If the page was mapped to a process, it can remain mapped 1793 * through the rename. vm_page_iter_rename() will dirty the 1794 * page. 1795 */ 1796 if (!vm_page_iter_rename(&pages, p, object, new_pindex)) { 1797 vm_page_xunbusy(p); 1798 next = vm_object_collapse_scan_wait(&pages, object, 1799 NULL); 1800 continue; 1801 } 1802 1803 /* Use the old pindex to free the right page. */ 1804 vm_pager_freespace(backing_object, new_pindex + 1805 backing_offset_index, 1); 1806 1807 #if VM_NRESERVLEVEL > 0 1808 /* 1809 * Rename the reservation. 1810 */ 1811 vm_reserv_rename(p, object, backing_object, 1812 backing_offset_index); 1813 #endif 1814 vm_page_xunbusy(p); 1815 next = vm_radix_iter_step(&pages); 1816 } 1817 return; 1818 } 1819 1820 /* 1821 * vm_object_collapse: 1822 * 1823 * Collapse an object with the object backing it. 1824 * Pages in the backing object are moved into the 1825 * parent, and the backing object is deallocated. 1826 */ 1827 void 1828 vm_object_collapse(vm_object_t object) 1829 { 1830 vm_object_t backing_object, new_backing_object; 1831 1832 VM_OBJECT_ASSERT_WLOCKED(object); 1833 1834 while (TRUE) { 1835 KASSERT((object->flags & (OBJ_DEAD | OBJ_ANON)) == OBJ_ANON, 1836 ("collapsing invalid object")); 1837 1838 /* 1839 * Wait for the backing_object to finish any pending 1840 * collapse so that the caller sees the shortest possible 1841 * shadow chain. 1842 */ 1843 backing_object = vm_object_backing_collapse_wait(object); 1844 if (backing_object == NULL) 1845 return; 1846 1847 KASSERT(object->ref_count > 0 && 1848 object->ref_count > atomic_load_int(&object->shadow_count), 1849 ("collapse with invalid ref %d or shadow %d count.", 1850 object->ref_count, atomic_load_int(&object->shadow_count))); 1851 KASSERT((backing_object->flags & 1852 (OBJ_COLLAPSING | OBJ_DEAD)) == 0, 1853 ("vm_object_collapse: Backing object already collapsing.")); 1854 KASSERT((object->flags & (OBJ_COLLAPSING | OBJ_DEAD)) == 0, 1855 ("vm_object_collapse: object is already collapsing.")); 1856 1857 /* 1858 * We know that we can either collapse the backing object if 1859 * the parent is the only reference to it, or (perhaps) have 1860 * the parent bypass the object if the parent happens to shadow 1861 * all the resident pages in the entire backing object. 1862 */ 1863 if (backing_object->ref_count == 1) { 1864 KASSERT(atomic_load_int(&backing_object->shadow_count) 1865 == 1, 1866 ("vm_object_collapse: shadow_count: %d", 1867 atomic_load_int(&backing_object->shadow_count))); 1868 vm_object_pip_add(object, 1); 1869 vm_object_set_flag(object, OBJ_COLLAPSING); 1870 vm_object_pip_add(backing_object, 1); 1871 vm_object_set_flag(backing_object, OBJ_DEAD); 1872 1873 /* 1874 * If there is exactly one reference to the backing 1875 * object, we can collapse it into the parent. 1876 */ 1877 vm_object_collapse_scan(object); 1878 1879 /* 1880 * Move the pager from backing_object to object. 1881 * 1882 * swap_pager_copy() can sleep, in which case the 1883 * backing_object's and object's locks are released and 1884 * reacquired. 1885 */ 1886 swap_pager_copy(backing_object, object, 1887 OFF_TO_IDX(object->backing_object_offset), TRUE); 1888 1889 /* 1890 * Object now shadows whatever backing_object did. 1891 */ 1892 vm_object_clear_flag(object, OBJ_COLLAPSING); 1893 vm_object_backing_transfer(object, backing_object); 1894 object->backing_object_offset += 1895 backing_object->backing_object_offset; 1896 VM_OBJECT_WUNLOCK(object); 1897 vm_object_pip_wakeup(object); 1898 1899 /* 1900 * Discard backing_object. 1901 * 1902 * Since the backing object has no pages, no pager left, 1903 * and no object references within it, all that is 1904 * necessary is to dispose of it. 1905 */ 1906 KASSERT(backing_object->ref_count == 1, ( 1907 "backing_object %p was somehow re-referenced during collapse!", 1908 backing_object)); 1909 vm_object_pip_wakeup(backing_object); 1910 (void)refcount_release(&backing_object->ref_count); 1911 umtx_shm_object_terminated(backing_object); 1912 vm_object_terminate(backing_object); 1913 counter_u64_add(object_collapses, 1); 1914 VM_OBJECT_WLOCK(object); 1915 } else { 1916 /* 1917 * If we do not entirely shadow the backing object, 1918 * there is nothing we can do so we give up. 1919 * 1920 * The object lock and backing_object lock must not 1921 * be dropped during this sequence. 1922 */ 1923 if (!swap_pager_scan_all_shadowed(object)) { 1924 VM_OBJECT_WUNLOCK(backing_object); 1925 break; 1926 } 1927 1928 /* 1929 * Make the parent shadow the next object in the 1930 * chain. Deallocating backing_object will not remove 1931 * it, since its reference count is at least 2. 1932 */ 1933 vm_object_backing_remove_locked(object); 1934 new_backing_object = backing_object->backing_object; 1935 if (new_backing_object != NULL) { 1936 vm_object_backing_insert_ref(object, 1937 new_backing_object); 1938 object->backing_object_offset += 1939 backing_object->backing_object_offset; 1940 } 1941 1942 /* 1943 * Drop the reference count on backing_object. Since 1944 * its ref_count was at least 2, it will not vanish. 1945 */ 1946 (void)refcount_release(&backing_object->ref_count); 1947 KASSERT(backing_object->ref_count >= 1, ( 1948 "backing_object %p was somehow dereferenced during collapse!", 1949 backing_object)); 1950 VM_OBJECT_WUNLOCK(backing_object); 1951 counter_u64_add(object_bypasses, 1); 1952 } 1953 1954 /* 1955 * Try again with this object's new backing object. 1956 */ 1957 } 1958 } 1959 1960 /* 1961 * vm_object_page_remove: 1962 * 1963 * For the given object, either frees or invalidates each of the 1964 * specified pages. In general, a page is freed. However, if a page is 1965 * wired for any reason other than the existence of a managed, wired 1966 * mapping, then it may be invalidated but not removed from the object. 1967 * Pages are specified by the given range ["start", "end") and the option 1968 * OBJPR_CLEANONLY. As a special case, if "end" is zero, then the range 1969 * extends from "start" to the end of the object. If the option 1970 * OBJPR_CLEANONLY is specified, then only the non-dirty pages within the 1971 * specified range are affected. If the option OBJPR_NOTMAPPED is 1972 * specified, then the pages within the specified range must have no 1973 * mappings. Otherwise, if this option is not specified, any mappings to 1974 * the specified pages are removed before the pages are freed or 1975 * invalidated. 1976 * 1977 * In general, this operation should only be performed on objects that 1978 * contain managed pages. There are, however, two exceptions. First, it 1979 * is performed on the kernel and kmem objects by vm_map_entry_delete(). 1980 * Second, it is used by msync(..., MS_INVALIDATE) to invalidate device- 1981 * backed pages. In both of these cases, the option OBJPR_CLEANONLY must 1982 * not be specified and the option OBJPR_NOTMAPPED must be specified. 1983 * 1984 * The object must be locked. 1985 */ 1986 void 1987 vm_object_page_remove(vm_object_t object, vm_pindex_t start, vm_pindex_t end, 1988 int options) 1989 { 1990 struct pctrie_iter pages; 1991 vm_page_t p; 1992 1993 VM_OBJECT_ASSERT_WLOCKED(object); 1994 KASSERT((object->flags & OBJ_UNMANAGED) == 0 || 1995 (options & (OBJPR_CLEANONLY | OBJPR_NOTMAPPED)) == OBJPR_NOTMAPPED, 1996 ("vm_object_page_remove: illegal options for object %p", object)); 1997 if (object->resident_page_count == 0) 1998 return; 1999 vm_object_pip_add(object, 1); 2000 vm_page_iter_limit_init(&pages, object, end); 2001 again: 2002 pctrie_iter_reset(&pages); 2003 for (p = vm_page_iter_lookup_ge(&pages, start); p != NULL; 2004 p = vm_radix_iter_step(&pages)) { 2005 /* 2006 * Skip invalid pages if asked to do so. Try to avoid acquiring 2007 * the busy lock, as some consumers rely on this to avoid 2008 * deadlocks. 2009 * 2010 * A thread may concurrently transition the page from invalid to 2011 * valid using only the busy lock, so the result of this check 2012 * is immediately stale. It is up to consumers to handle this, 2013 * for instance by ensuring that all invalid->valid transitions 2014 * happen with a mutex held, as may be possible for a 2015 * filesystem. 2016 */ 2017 if ((options & OBJPR_VALIDONLY) != 0 && vm_page_none_valid(p)) 2018 continue; 2019 2020 /* 2021 * If the page is wired for any reason besides the existence 2022 * of managed, wired mappings, then it cannot be freed. For 2023 * example, fictitious pages, which represent device memory, 2024 * are inherently wired and cannot be freed. They can, 2025 * however, be invalidated if the option OBJPR_CLEANONLY is 2026 * not specified. 2027 */ 2028 if (vm_page_tryxbusy(p) == 0) { 2029 if (vm_page_busy_sleep(p, "vmopar", 0)) 2030 VM_OBJECT_WLOCK(object); 2031 goto again; 2032 } 2033 if ((options & OBJPR_VALIDONLY) != 0 && vm_page_none_valid(p)) { 2034 vm_page_xunbusy(p); 2035 continue; 2036 } 2037 if (vm_page_wired(p)) { 2038 wired: 2039 if ((options & OBJPR_NOTMAPPED) == 0 && 2040 object->ref_count != 0) 2041 pmap_remove_all(p); 2042 if ((options & OBJPR_CLEANONLY) == 0) { 2043 vm_page_invalid(p); 2044 vm_page_undirty(p); 2045 } 2046 vm_page_xunbusy(p); 2047 continue; 2048 } 2049 KASSERT((p->flags & PG_FICTITIOUS) == 0, 2050 ("vm_object_page_remove: page %p is fictitious", p)); 2051 if ((options & OBJPR_CLEANONLY) != 0 && 2052 !vm_page_none_valid(p)) { 2053 if ((options & OBJPR_NOTMAPPED) == 0 && 2054 object->ref_count != 0 && 2055 !vm_page_try_remove_write(p)) 2056 goto wired; 2057 if (p->dirty != 0) { 2058 vm_page_xunbusy(p); 2059 continue; 2060 } 2061 } 2062 if ((options & OBJPR_NOTMAPPED) == 0 && 2063 object->ref_count != 0 && !vm_page_try_remove_all(p)) 2064 goto wired; 2065 vm_page_iter_free(&pages, p); 2066 } 2067 vm_object_pip_wakeup(object); 2068 2069 vm_pager_freespace(object, start, (end == 0 ? object->size : end) - 2070 start); 2071 } 2072 2073 /* 2074 * vm_object_page_noreuse: 2075 * 2076 * For the given object, attempt to move the specified pages to 2077 * the head of the inactive queue. This bypasses regular LRU 2078 * operation and allows the pages to be reused quickly under memory 2079 * pressure. If a page is wired for any reason, then it will not 2080 * be queued. Pages are specified by the range ["start", "end"). 2081 * As a special case, if "end" is zero, then the range extends from 2082 * "start" to the end of the object. 2083 * 2084 * This operation should only be performed on objects that 2085 * contain non-fictitious, managed pages. 2086 * 2087 * The object must be locked. 2088 */ 2089 void 2090 vm_object_page_noreuse(vm_object_t object, vm_pindex_t start, vm_pindex_t end) 2091 { 2092 vm_page_t p, next; 2093 2094 VM_OBJECT_ASSERT_LOCKED(object); 2095 KASSERT((object->flags & (OBJ_FICTITIOUS | OBJ_UNMANAGED)) == 0, 2096 ("vm_object_page_noreuse: illegal object %p", object)); 2097 if (object->resident_page_count == 0) 2098 return; 2099 p = vm_page_find_least(object, start); 2100 2101 /* 2102 * Here, the variable "p" is either (1) the page with the least pindex 2103 * greater than or equal to the parameter "start" or (2) NULL. 2104 */ 2105 for (; p != NULL && (p->pindex < end || end == 0); p = next) { 2106 next = TAILQ_NEXT(p, listq); 2107 vm_page_deactivate_noreuse(p); 2108 } 2109 } 2110 2111 /* 2112 * Populate the specified range of the object with valid pages. Returns 2113 * TRUE if the range is successfully populated and FALSE otherwise. 2114 * 2115 * Note: This function should be optimized to pass a larger array of 2116 * pages to vm_pager_get_pages() before it is applied to a non- 2117 * OBJT_DEVICE object. 2118 * 2119 * The object must be locked. 2120 */ 2121 boolean_t 2122 vm_object_populate(vm_object_t object, vm_pindex_t start, vm_pindex_t end) 2123 { 2124 vm_page_t m; 2125 vm_pindex_t pindex; 2126 int rv; 2127 2128 VM_OBJECT_ASSERT_WLOCKED(object); 2129 for (pindex = start; pindex < end; pindex++) { 2130 rv = vm_page_grab_valid(&m, object, pindex, VM_ALLOC_NORMAL); 2131 if (rv != VM_PAGER_OK) 2132 break; 2133 2134 /* 2135 * Keep "m" busy because a subsequent iteration may unlock 2136 * the object. 2137 */ 2138 } 2139 if (pindex > start) { 2140 m = vm_page_lookup(object, start); 2141 while (m != NULL && m->pindex < pindex) { 2142 vm_page_xunbusy(m); 2143 m = TAILQ_NEXT(m, listq); 2144 } 2145 } 2146 return (pindex == end); 2147 } 2148 2149 /* 2150 * Routine: vm_object_coalesce 2151 * Function: Coalesces two objects backing up adjoining 2152 * regions of memory into a single object. 2153 * 2154 * returns TRUE if objects were combined. 2155 * 2156 * NOTE: Only works at the moment if the second object is NULL - 2157 * if it's not, which object do we lock first? 2158 * 2159 * Parameters: 2160 * prev_object First object to coalesce 2161 * prev_offset Offset into prev_object 2162 * prev_size Size of reference to prev_object 2163 * next_size Size of reference to the second object 2164 * reserved Indicator that extension region has 2165 * swap accounted for 2166 * 2167 * Conditions: 2168 * The object must *not* be locked. 2169 */ 2170 boolean_t 2171 vm_object_coalesce(vm_object_t prev_object, vm_ooffset_t prev_offset, 2172 vm_size_t prev_size, vm_size_t next_size, boolean_t reserved) 2173 { 2174 vm_pindex_t next_pindex; 2175 2176 if (prev_object == NULL) 2177 return (TRUE); 2178 if ((prev_object->flags & OBJ_ANON) == 0) 2179 return (FALSE); 2180 2181 VM_OBJECT_WLOCK(prev_object); 2182 /* 2183 * Try to collapse the object first. 2184 */ 2185 vm_object_collapse(prev_object); 2186 2187 /* 2188 * Can't coalesce if: . more than one reference . paged out . shadows 2189 * another object . has a copy elsewhere (any of which mean that the 2190 * pages not mapped to prev_entry may be in use anyway) 2191 */ 2192 if (prev_object->backing_object != NULL) { 2193 VM_OBJECT_WUNLOCK(prev_object); 2194 return (FALSE); 2195 } 2196 2197 prev_size >>= PAGE_SHIFT; 2198 next_size >>= PAGE_SHIFT; 2199 next_pindex = OFF_TO_IDX(prev_offset) + prev_size; 2200 2201 if (prev_object->ref_count > 1 && 2202 prev_object->size != next_pindex && 2203 (prev_object->flags & OBJ_ONEMAPPING) == 0) { 2204 VM_OBJECT_WUNLOCK(prev_object); 2205 return (FALSE); 2206 } 2207 2208 /* 2209 * Account for the charge. 2210 */ 2211 if (prev_object->cred != NULL) { 2212 /* 2213 * If prev_object was charged, then this mapping, 2214 * although not charged now, may become writable 2215 * later. Non-NULL cred in the object would prevent 2216 * swap reservation during enabling of the write 2217 * access, so reserve swap now. Failed reservation 2218 * cause allocation of the separate object for the map 2219 * entry, and swap reservation for this entry is 2220 * managed in appropriate time. 2221 */ 2222 if (!reserved && !swap_reserve_by_cred(ptoa(next_size), 2223 prev_object->cred)) { 2224 VM_OBJECT_WUNLOCK(prev_object); 2225 return (FALSE); 2226 } 2227 prev_object->charge += ptoa(next_size); 2228 } 2229 2230 /* 2231 * Remove any pages that may still be in the object from a previous 2232 * deallocation. 2233 */ 2234 if (next_pindex < prev_object->size) { 2235 vm_object_page_remove(prev_object, next_pindex, next_pindex + 2236 next_size, 0); 2237 #if 0 2238 if (prev_object->cred != NULL) { 2239 KASSERT(prev_object->charge >= 2240 ptoa(prev_object->size - next_pindex), 2241 ("object %p overcharged 1 %jx %jx", prev_object, 2242 (uintmax_t)next_pindex, (uintmax_t)next_size)); 2243 prev_object->charge -= ptoa(prev_object->size - 2244 next_pindex); 2245 } 2246 #endif 2247 } 2248 2249 /* 2250 * Extend the object if necessary. 2251 */ 2252 if (next_pindex + next_size > prev_object->size) 2253 prev_object->size = next_pindex + next_size; 2254 2255 VM_OBJECT_WUNLOCK(prev_object); 2256 return (TRUE); 2257 } 2258 2259 void 2260 vm_object_set_writeable_dirty_(vm_object_t object) 2261 { 2262 atomic_add_int(&object->generation, 1); 2263 } 2264 2265 bool 2266 vm_object_mightbedirty_(vm_object_t object) 2267 { 2268 return (object->generation != object->cleangeneration); 2269 } 2270 2271 /* 2272 * vm_object_unwire: 2273 * 2274 * For each page offset within the specified range of the given object, 2275 * find the highest-level page in the shadow chain and unwire it. A page 2276 * must exist at every page offset, and the highest-level page must be 2277 * wired. 2278 */ 2279 void 2280 vm_object_unwire(vm_object_t object, vm_ooffset_t offset, vm_size_t length, 2281 uint8_t queue) 2282 { 2283 vm_object_t tobject, t1object; 2284 vm_page_t m, tm; 2285 vm_pindex_t end_pindex, pindex, tpindex; 2286 int depth, locked_depth; 2287 2288 KASSERT((offset & PAGE_MASK) == 0, 2289 ("vm_object_unwire: offset is not page aligned")); 2290 KASSERT((length & PAGE_MASK) == 0, 2291 ("vm_object_unwire: length is not a multiple of PAGE_SIZE")); 2292 /* The wired count of a fictitious page never changes. */ 2293 if ((object->flags & OBJ_FICTITIOUS) != 0) 2294 return; 2295 pindex = OFF_TO_IDX(offset); 2296 end_pindex = pindex + atop(length); 2297 again: 2298 locked_depth = 1; 2299 VM_OBJECT_RLOCK(object); 2300 m = vm_page_find_least(object, pindex); 2301 while (pindex < end_pindex) { 2302 if (m == NULL || pindex < m->pindex) { 2303 /* 2304 * The first object in the shadow chain doesn't 2305 * contain a page at the current index. Therefore, 2306 * the page must exist in a backing object. 2307 */ 2308 tobject = object; 2309 tpindex = pindex; 2310 depth = 0; 2311 do { 2312 tpindex += 2313 OFF_TO_IDX(tobject->backing_object_offset); 2314 tobject = tobject->backing_object; 2315 KASSERT(tobject != NULL, 2316 ("vm_object_unwire: missing page")); 2317 if ((tobject->flags & OBJ_FICTITIOUS) != 0) 2318 goto next_page; 2319 depth++; 2320 if (depth == locked_depth) { 2321 locked_depth++; 2322 VM_OBJECT_RLOCK(tobject); 2323 } 2324 } while ((tm = vm_page_lookup(tobject, tpindex)) == 2325 NULL); 2326 } else { 2327 tm = m; 2328 m = TAILQ_NEXT(m, listq); 2329 } 2330 if (vm_page_trysbusy(tm) == 0) { 2331 for (tobject = object; locked_depth >= 1; 2332 locked_depth--) { 2333 t1object = tobject->backing_object; 2334 if (tm->object != tobject) 2335 VM_OBJECT_RUNLOCK(tobject); 2336 tobject = t1object; 2337 } 2338 tobject = tm->object; 2339 if (!vm_page_busy_sleep(tm, "unwbo", 2340 VM_ALLOC_IGN_SBUSY)) 2341 VM_OBJECT_RUNLOCK(tobject); 2342 goto again; 2343 } 2344 vm_page_unwire(tm, queue); 2345 vm_page_sunbusy(tm); 2346 next_page: 2347 pindex++; 2348 } 2349 /* Release the accumulated object locks. */ 2350 for (tobject = object; locked_depth >= 1; locked_depth--) { 2351 t1object = tobject->backing_object; 2352 VM_OBJECT_RUNLOCK(tobject); 2353 tobject = t1object; 2354 } 2355 } 2356 2357 /* 2358 * Return the vnode for the given object, or NULL if none exists. 2359 * For tmpfs objects, the function may return NULL if there is 2360 * no vnode allocated at the time of the call. 2361 */ 2362 struct vnode * 2363 vm_object_vnode(vm_object_t object) 2364 { 2365 struct vnode *vp; 2366 2367 VM_OBJECT_ASSERT_LOCKED(object); 2368 vm_pager_getvp(object, &vp, NULL); 2369 return (vp); 2370 } 2371 2372 /* 2373 * Busy the vm object. This prevents new pages belonging to the object from 2374 * becoming busy. Existing pages persist as busy. Callers are responsible 2375 * for checking page state before proceeding. 2376 */ 2377 void 2378 vm_object_busy(vm_object_t obj) 2379 { 2380 2381 VM_OBJECT_ASSERT_LOCKED(obj); 2382 2383 blockcount_acquire(&obj->busy, 1); 2384 /* The fence is required to order loads of page busy. */ 2385 atomic_thread_fence_acq_rel(); 2386 } 2387 2388 void 2389 vm_object_unbusy(vm_object_t obj) 2390 { 2391 2392 blockcount_release(&obj->busy, 1); 2393 } 2394 2395 void 2396 vm_object_busy_wait(vm_object_t obj, const char *wmesg) 2397 { 2398 2399 VM_OBJECT_ASSERT_UNLOCKED(obj); 2400 2401 (void)blockcount_sleep(&obj->busy, NULL, wmesg, PVM); 2402 } 2403 2404 /* 2405 * This function aims to determine if the object is mapped, 2406 * specifically, if it is referenced by a vm_map_entry. Because 2407 * objects occasionally acquire transient references that do not 2408 * represent a mapping, the method used here is inexact. However, it 2409 * has very low overhead and is good enough for the advisory 2410 * vm.vmtotal sysctl. 2411 */ 2412 bool 2413 vm_object_is_active(vm_object_t obj) 2414 { 2415 2416 return (obj->ref_count > atomic_load_int(&obj->shadow_count)); 2417 } 2418 2419 static int 2420 vm_object_list_handler(struct sysctl_req *req, bool swap_only) 2421 { 2422 struct kinfo_vmobject *kvo; 2423 char *fullpath, *freepath; 2424 struct vnode *vp; 2425 struct vattr va; 2426 vm_object_t obj; 2427 vm_page_t m; 2428 struct cdev *cdev; 2429 struct cdevsw *csw; 2430 u_long sp; 2431 int count, error, ref; 2432 key_t key; 2433 unsigned short seq; 2434 bool want_path; 2435 2436 if (req->oldptr == NULL) { 2437 /* 2438 * If an old buffer has not been provided, generate an 2439 * estimate of the space needed for a subsequent call. 2440 */ 2441 mtx_lock(&vm_object_list_mtx); 2442 count = 0; 2443 TAILQ_FOREACH(obj, &vm_object_list, object_list) { 2444 if (obj->type == OBJT_DEAD) 2445 continue; 2446 count++; 2447 } 2448 mtx_unlock(&vm_object_list_mtx); 2449 return (SYSCTL_OUT(req, NULL, sizeof(struct kinfo_vmobject) * 2450 count * 11 / 10)); 2451 } 2452 2453 want_path = !(swap_only || jailed(curthread->td_ucred)); 2454 kvo = malloc(sizeof(*kvo), M_TEMP, M_WAITOK | M_ZERO); 2455 error = 0; 2456 2457 /* 2458 * VM objects are type stable and are never removed from the 2459 * list once added. This allows us to safely read obj->object_list 2460 * after reacquiring the VM object lock. 2461 */ 2462 mtx_lock(&vm_object_list_mtx); 2463 TAILQ_FOREACH(obj, &vm_object_list, object_list) { 2464 if (obj->type == OBJT_DEAD || 2465 (swap_only && (obj->flags & (OBJ_ANON | OBJ_SWAP)) == 0)) 2466 continue; 2467 VM_OBJECT_RLOCK(obj); 2468 if (obj->type == OBJT_DEAD || 2469 (swap_only && (obj->flags & (OBJ_ANON | OBJ_SWAP)) == 0)) { 2470 VM_OBJECT_RUNLOCK(obj); 2471 continue; 2472 } 2473 mtx_unlock(&vm_object_list_mtx); 2474 kvo->kvo_size = ptoa(obj->size); 2475 kvo->kvo_resident = obj->resident_page_count; 2476 kvo->kvo_ref_count = obj->ref_count; 2477 kvo->kvo_shadow_count = atomic_load_int(&obj->shadow_count); 2478 kvo->kvo_memattr = obj->memattr; 2479 kvo->kvo_active = 0; 2480 kvo->kvo_inactive = 0; 2481 kvo->kvo_flags = 0; 2482 if (!swap_only) { 2483 TAILQ_FOREACH(m, &obj->memq, listq) { 2484 /* 2485 * A page may belong to the object but be 2486 * dequeued and set to PQ_NONE while the 2487 * object lock is not held. This makes the 2488 * reads of m->queue below racy, and we do not 2489 * count pages set to PQ_NONE. However, this 2490 * sysctl is only meant to give an 2491 * approximation of the system anyway. 2492 */ 2493 if (vm_page_active(m)) 2494 kvo->kvo_active++; 2495 else if (vm_page_inactive(m)) 2496 kvo->kvo_inactive++; 2497 else if (vm_page_in_laundry(m)) 2498 kvo->kvo_laundry++; 2499 } 2500 } 2501 2502 kvo->kvo_vn_fileid = 0; 2503 kvo->kvo_vn_fsid = 0; 2504 kvo->kvo_vn_fsid_freebsd11 = 0; 2505 freepath = NULL; 2506 fullpath = ""; 2507 vp = NULL; 2508 kvo->kvo_type = vm_object_kvme_type(obj, want_path ? &vp : 2509 NULL); 2510 if (vp != NULL) { 2511 vref(vp); 2512 } else if ((obj->flags & OBJ_ANON) != 0) { 2513 MPASS(kvo->kvo_type == KVME_TYPE_SWAP); 2514 kvo->kvo_me = (uintptr_t)obj; 2515 /* tmpfs objs are reported as vnodes */ 2516 kvo->kvo_backing_obj = (uintptr_t)obj->backing_object; 2517 sp = swap_pager_swapped_pages(obj); 2518 kvo->kvo_swapped = sp > UINT32_MAX ? UINT32_MAX : sp; 2519 } 2520 if ((obj->type == OBJT_DEVICE || obj->type == OBJT_MGTDEVICE) && 2521 (obj->flags & OBJ_CDEVH) != 0) { 2522 cdev = obj->un_pager.devp.handle; 2523 if (cdev != NULL) { 2524 csw = dev_refthread(cdev, &ref); 2525 if (csw != NULL) { 2526 strlcpy(kvo->kvo_path, cdev->si_name, 2527 sizeof(kvo->kvo_path)); 2528 dev_relthread(cdev, ref); 2529 } 2530 } 2531 } 2532 VM_OBJECT_RUNLOCK(obj); 2533 if ((obj->flags & OBJ_SYSVSHM) != 0) { 2534 kvo->kvo_flags |= KVMO_FLAG_SYSVSHM; 2535 shmobjinfo(obj, &key, &seq); 2536 kvo->kvo_vn_fileid = key; 2537 kvo->kvo_vn_fsid_freebsd11 = seq; 2538 } 2539 if ((obj->flags & OBJ_POSIXSHM) != 0) { 2540 kvo->kvo_flags |= KVMO_FLAG_POSIXSHM; 2541 shm_get_path(obj, kvo->kvo_path, 2542 sizeof(kvo->kvo_path)); 2543 } 2544 if (vp != NULL) { 2545 vn_fullpath(vp, &fullpath, &freepath); 2546 vn_lock(vp, LK_SHARED | LK_RETRY); 2547 if (VOP_GETATTR(vp, &va, curthread->td_ucred) == 0) { 2548 kvo->kvo_vn_fileid = va.va_fileid; 2549 kvo->kvo_vn_fsid = va.va_fsid; 2550 kvo->kvo_vn_fsid_freebsd11 = va.va_fsid; 2551 /* truncate */ 2552 } 2553 vput(vp); 2554 strlcpy(kvo->kvo_path, fullpath, sizeof(kvo->kvo_path)); 2555 free(freepath, M_TEMP); 2556 } 2557 2558 /* Pack record size down */ 2559 kvo->kvo_structsize = offsetof(struct kinfo_vmobject, kvo_path) 2560 + strlen(kvo->kvo_path) + 1; 2561 kvo->kvo_structsize = roundup(kvo->kvo_structsize, 2562 sizeof(uint64_t)); 2563 error = SYSCTL_OUT(req, kvo, kvo->kvo_structsize); 2564 maybe_yield(); 2565 mtx_lock(&vm_object_list_mtx); 2566 if (error) 2567 break; 2568 } 2569 mtx_unlock(&vm_object_list_mtx); 2570 free(kvo, M_TEMP); 2571 return (error); 2572 } 2573 2574 static int 2575 sysctl_vm_object_list(SYSCTL_HANDLER_ARGS) 2576 { 2577 return (vm_object_list_handler(req, false)); 2578 } 2579 2580 SYSCTL_PROC(_vm, OID_AUTO, objects, CTLTYPE_STRUCT | CTLFLAG_RW | CTLFLAG_SKIP | 2581 CTLFLAG_MPSAFE, NULL, 0, sysctl_vm_object_list, "S,kinfo_vmobject", 2582 "List of VM objects"); 2583 2584 static int 2585 sysctl_vm_object_list_swap(SYSCTL_HANDLER_ARGS) 2586 { 2587 return (vm_object_list_handler(req, true)); 2588 } 2589 2590 /* 2591 * This sysctl returns list of the anonymous or swap objects. Intent 2592 * is to provide stripped optimized list useful to analyze swap use. 2593 * Since technically non-swap (default) objects participate in the 2594 * shadow chains, and are converted to swap type as needed by swap 2595 * pager, we must report them. 2596 */ 2597 SYSCTL_PROC(_vm, OID_AUTO, swap_objects, 2598 CTLTYPE_STRUCT | CTLFLAG_RW | CTLFLAG_SKIP | CTLFLAG_MPSAFE, NULL, 0, 2599 sysctl_vm_object_list_swap, "S,kinfo_vmobject", 2600 "List of swap VM objects"); 2601 2602 #include "opt_ddb.h" 2603 #ifdef DDB 2604 #include <sys/kernel.h> 2605 2606 #include <sys/cons.h> 2607 2608 #include <ddb/ddb.h> 2609 2610 static int 2611 _vm_object_in_map(vm_map_t map, vm_object_t object, vm_map_entry_t entry) 2612 { 2613 vm_map_t tmpm; 2614 vm_map_entry_t tmpe; 2615 vm_object_t obj; 2616 2617 if (map == 0) 2618 return 0; 2619 2620 if (entry == 0) { 2621 VM_MAP_ENTRY_FOREACH(tmpe, map) { 2622 if (_vm_object_in_map(map, object, tmpe)) { 2623 return 1; 2624 } 2625 } 2626 } else if (entry->eflags & MAP_ENTRY_IS_SUB_MAP) { 2627 tmpm = entry->object.sub_map; 2628 VM_MAP_ENTRY_FOREACH(tmpe, tmpm) { 2629 if (_vm_object_in_map(tmpm, object, tmpe)) { 2630 return 1; 2631 } 2632 } 2633 } else if ((obj = entry->object.vm_object) != NULL) { 2634 for (; obj; obj = obj->backing_object) 2635 if (obj == object) { 2636 return 1; 2637 } 2638 } 2639 return 0; 2640 } 2641 2642 static int 2643 vm_object_in_map(vm_object_t object) 2644 { 2645 struct proc *p; 2646 2647 /* sx_slock(&allproc_lock); */ 2648 FOREACH_PROC_IN_SYSTEM(p) { 2649 if (!p->p_vmspace /* || (p->p_flag & (P_SYSTEM|P_WEXIT)) */) 2650 continue; 2651 if (_vm_object_in_map(&p->p_vmspace->vm_map, object, 0)) { 2652 /* sx_sunlock(&allproc_lock); */ 2653 return 1; 2654 } 2655 } 2656 /* sx_sunlock(&allproc_lock); */ 2657 if (_vm_object_in_map(kernel_map, object, 0)) 2658 return 1; 2659 return 0; 2660 } 2661 2662 DB_SHOW_COMMAND_FLAGS(vmochk, vm_object_check, DB_CMD_MEMSAFE) 2663 { 2664 vm_object_t object; 2665 2666 /* 2667 * make sure that internal objs are in a map somewhere 2668 * and none have zero ref counts. 2669 */ 2670 TAILQ_FOREACH(object, &vm_object_list, object_list) { 2671 if ((object->flags & OBJ_ANON) != 0) { 2672 if (object->ref_count == 0) { 2673 db_printf("vmochk: internal obj has zero ref count: %ld\n", 2674 (long)object->size); 2675 } 2676 if (!vm_object_in_map(object)) { 2677 db_printf( 2678 "vmochk: internal obj is not in a map: " 2679 "ref: %d, size: %lu: 0x%lx, backing_object: %p\n", 2680 object->ref_count, (u_long)object->size, 2681 (u_long)object->size, 2682 (void *)object->backing_object); 2683 } 2684 } 2685 if (db_pager_quit) 2686 return; 2687 } 2688 } 2689 2690 /* 2691 * vm_object_print: [ debug ] 2692 */ 2693 DB_SHOW_COMMAND(object, vm_object_print_static) 2694 { 2695 /* XXX convert args. */ 2696 vm_object_t object = (vm_object_t)addr; 2697 boolean_t full = have_addr; 2698 2699 vm_page_t p; 2700 2701 /* XXX count is an (unused) arg. Avoid shadowing it. */ 2702 #define count was_count 2703 2704 int count; 2705 2706 if (object == NULL) 2707 return; 2708 2709 db_iprintf( 2710 "Object %p: type=%d, size=0x%jx, res=%d, ref=%d, flags=0x%x ruid %d charge %jx\n", 2711 object, (int)object->type, (uintmax_t)object->size, 2712 object->resident_page_count, object->ref_count, object->flags, 2713 object->cred ? object->cred->cr_ruid : -1, (uintmax_t)object->charge); 2714 db_iprintf(" sref=%d, backing_object(%d)=(%p)+0x%jx\n", 2715 atomic_load_int(&object->shadow_count), 2716 object->backing_object ? object->backing_object->ref_count : 0, 2717 object->backing_object, (uintmax_t)object->backing_object_offset); 2718 2719 if (!full) 2720 return; 2721 2722 db_indent += 2; 2723 count = 0; 2724 TAILQ_FOREACH(p, &object->memq, listq) { 2725 if (count == 0) 2726 db_iprintf("memory:="); 2727 else if (count == 6) { 2728 db_printf("\n"); 2729 db_iprintf(" ..."); 2730 count = 0; 2731 } else 2732 db_printf(","); 2733 count++; 2734 2735 db_printf("(off=0x%jx,page=0x%jx)", 2736 (uintmax_t)p->pindex, (uintmax_t)VM_PAGE_TO_PHYS(p)); 2737 2738 if (db_pager_quit) 2739 break; 2740 } 2741 if (count != 0) 2742 db_printf("\n"); 2743 db_indent -= 2; 2744 } 2745 2746 /* XXX. */ 2747 #undef count 2748 2749 /* XXX need this non-static entry for calling from vm_map_print. */ 2750 void 2751 vm_object_print( 2752 /* db_expr_t */ long addr, 2753 boolean_t have_addr, 2754 /* db_expr_t */ long count, 2755 char *modif) 2756 { 2757 vm_object_print_static(addr, have_addr, count, modif); 2758 } 2759 2760 DB_SHOW_COMMAND_FLAGS(vmopag, vm_object_print_pages, DB_CMD_MEMSAFE) 2761 { 2762 vm_object_t object; 2763 vm_pindex_t fidx; 2764 vm_paddr_t pa; 2765 vm_page_t m, prev_m; 2766 int rcount; 2767 2768 TAILQ_FOREACH(object, &vm_object_list, object_list) { 2769 db_printf("new object: %p\n", (void *)object); 2770 if (db_pager_quit) 2771 return; 2772 2773 rcount = 0; 2774 fidx = 0; 2775 pa = -1; 2776 TAILQ_FOREACH(m, &object->memq, listq) { 2777 if ((prev_m = TAILQ_PREV(m, pglist, listq)) != NULL && 2778 prev_m->pindex + 1 != m->pindex) { 2779 if (rcount) { 2780 db_printf(" index(%ld)run(%d)pa(0x%lx)\n", 2781 (long)fidx, rcount, (long)pa); 2782 if (db_pager_quit) 2783 return; 2784 rcount = 0; 2785 } 2786 } 2787 if (rcount && 2788 (VM_PAGE_TO_PHYS(m) == pa + rcount * PAGE_SIZE)) { 2789 ++rcount; 2790 continue; 2791 } 2792 if (rcount) { 2793 db_printf(" index(%ld)run(%d)pa(0x%lx)\n", 2794 (long)fidx, rcount, (long)pa); 2795 if (db_pager_quit) 2796 return; 2797 } 2798 fidx = m->pindex; 2799 pa = VM_PAGE_TO_PHYS(m); 2800 rcount = 1; 2801 } 2802 if (rcount) { 2803 db_printf(" index(%ld)run(%d)pa(0x%lx)\n", 2804 (long)fidx, rcount, (long)pa); 2805 if (db_pager_quit) 2806 return; 2807 } 2808 } 2809 } 2810 #endif /* DDB */ 2811