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/cpuset.h> 70 #include <sys/jail.h> 71 #include <sys/limits.h> 72 #include <sys/lock.h> 73 #include <sys/mman.h> 74 #include <sys/mount.h> 75 #include <sys/kernel.h> 76 #include <sys/mutex.h> 77 #include <sys/pctrie.h> 78 #include <sys/proc.h> 79 #include <sys/refcount.h> 80 #include <sys/sx.h> 81 #include <sys/sysctl.h> 82 #include <sys/resourcevar.h> 83 #include <sys/refcount.h> 84 #include <sys/rwlock.h> 85 #include <sys/user.h> 86 #include <sys/vnode.h> 87 #include <sys/vmmeter.h> 88 89 #include <vm/vm.h> 90 #include <vm/vm_param.h> 91 #include <vm/pmap.h> 92 #include <vm/vm_map.h> 93 #include <vm/vm_object.h> 94 #include <vm/vm_page.h> 95 #include <vm/vm_pageout.h> 96 #include <vm/vm_pager.h> 97 #include <vm/vm_phys.h> 98 #include <vm/vm_pagequeue.h> 99 #include <vm/swap_pager.h> 100 #include <vm/vm_kern.h> 101 #include <vm/vm_extern.h> 102 #include <vm/vm_radix.h> 103 #include <vm/vm_reserv.h> 104 #include <vm/uma.h> 105 106 static int old_msync; 107 SYSCTL_INT(_vm, OID_AUTO, old_msync, CTLFLAG_RW, &old_msync, 0, 108 "Use old (insecure) msync behavior"); 109 110 static int vm_object_page_collect_flush(vm_object_t object, vm_page_t p, 111 int pagerflags, int flags, boolean_t *allclean, 112 boolean_t *eio); 113 static boolean_t vm_object_page_remove_write(vm_page_t p, int flags, 114 boolean_t *allclean); 115 static void vm_object_backing_remove(vm_object_t object); 116 117 /* 118 * Virtual memory objects maintain the actual data 119 * associated with allocated virtual memory. A given 120 * page of memory exists within exactly one object. 121 * 122 * An object is only deallocated when all "references" 123 * are given up. Only one "reference" to a given 124 * region of an object should be writeable. 125 * 126 * Associated with each object is a list of all resident 127 * memory pages belonging to that object; this list is 128 * maintained by the "vm_page" module, and locked by the object's 129 * lock. 130 * 131 * Each object also records a "pager" routine which is 132 * used to retrieve (and store) pages to the proper backing 133 * storage. In addition, objects may be backed by other 134 * objects from which they were virtual-copied. 135 * 136 * The only items within the object structure which are 137 * modified after time of creation are: 138 * reference count locked by object's lock 139 * pager routine locked by object's lock 140 * 141 */ 142 143 struct object_q vm_object_list; 144 struct mtx vm_object_list_mtx; /* lock for object list and count */ 145 146 struct vm_object kernel_object_store; 147 148 static SYSCTL_NODE(_vm_stats, OID_AUTO, object, CTLFLAG_RD | CTLFLAG_MPSAFE, 0, 149 "VM object stats"); 150 151 static COUNTER_U64_DEFINE_EARLY(object_collapses); 152 SYSCTL_COUNTER_U64(_vm_stats_object, OID_AUTO, collapses, CTLFLAG_RD, 153 &object_collapses, 154 "VM object collapses"); 155 156 static COUNTER_U64_DEFINE_EARLY(object_bypasses); 157 SYSCTL_COUNTER_U64(_vm_stats_object, OID_AUTO, bypasses, CTLFLAG_RD, 158 &object_bypasses, 159 "VM object bypasses"); 160 161 static COUNTER_U64_DEFINE_EARLY(object_collapse_waits); 162 SYSCTL_COUNTER_U64(_vm_stats_object, OID_AUTO, collapse_waits, CTLFLAG_RD, 163 &object_collapse_waits, 164 "Number of sleeps for collapse"); 165 166 static uma_zone_t obj_zone; 167 168 static int vm_object_zinit(void *mem, int size, int flags); 169 170 #ifdef INVARIANTS 171 static void vm_object_zdtor(void *mem, int size, void *arg); 172 173 static void 174 vm_object_zdtor(void *mem, int size, void *arg) 175 { 176 vm_object_t object; 177 178 object = (vm_object_t)mem; 179 KASSERT(object->ref_count == 0, 180 ("object %p ref_count = %d", object, object->ref_count)); 181 KASSERT(TAILQ_EMPTY(&object->memq), 182 ("object %p has resident pages in its memq", object)); 183 KASSERT(vm_radix_is_empty(&object->rtree), 184 ("object %p has resident pages in its trie", object)); 185 #if VM_NRESERVLEVEL > 0 186 KASSERT(LIST_EMPTY(&object->rvq), 187 ("object %p has reservations", 188 object)); 189 #endif 190 KASSERT(!vm_object_busied(object), 191 ("object %p busy = %d", object, blockcount_read(&object->busy))); 192 KASSERT(object->resident_page_count == 0, 193 ("object %p resident_page_count = %d", 194 object, object->resident_page_count)); 195 KASSERT(atomic_load_int(&object->shadow_count) == 0, 196 ("object %p shadow_count = %d", 197 object, atomic_load_int(&object->shadow_count))); 198 KASSERT(object->type == OBJT_DEAD, 199 ("object %p has non-dead type %d", 200 object, object->type)); 201 KASSERT(object->charge == 0 && object->cred == NULL, 202 ("object %p has non-zero charge %ju (%p)", 203 object, (uintmax_t)object->charge, object->cred)); 204 } 205 #endif 206 207 static int 208 vm_object_zinit(void *mem, int size, int flags) 209 { 210 vm_object_t object; 211 212 object = (vm_object_t)mem; 213 rw_init_flags(&object->lock, "vmobject", RW_DUPOK | RW_NEW); 214 215 /* These are true for any object that has been freed */ 216 object->type = OBJT_DEAD; 217 vm_radix_init(&object->rtree); 218 refcount_init(&object->ref_count, 0); 219 blockcount_init(&object->paging_in_progress); 220 blockcount_init(&object->busy); 221 object->resident_page_count = 0; 222 atomic_store_int(&object->shadow_count, 0); 223 object->flags = OBJ_DEAD; 224 225 mtx_lock(&vm_object_list_mtx); 226 TAILQ_INSERT_TAIL(&vm_object_list, object, object_list); 227 mtx_unlock(&vm_object_list_mtx); 228 return (0); 229 } 230 231 static void 232 _vm_object_allocate(objtype_t type, vm_pindex_t size, u_short flags, 233 vm_object_t object, void *handle) 234 { 235 236 TAILQ_INIT(&object->memq); 237 LIST_INIT(&object->shadow_head); 238 239 object->type = type; 240 object->flags = flags; 241 if ((flags & OBJ_SWAP) != 0) { 242 pctrie_init(&object->un_pager.swp.swp_blks); 243 object->un_pager.swp.writemappings = 0; 244 } 245 246 /* 247 * Ensure that swap_pager_swapoff() iteration over object_list 248 * sees up to date type and pctrie head if it observed 249 * non-dead object. 250 */ 251 atomic_thread_fence_rel(); 252 253 object->pg_color = 0; 254 object->size = size; 255 object->domain.dr_policy = NULL; 256 object->generation = 1; 257 object->cleangeneration = 1; 258 refcount_init(&object->ref_count, 1); 259 object->memattr = VM_MEMATTR_DEFAULT; 260 object->cred = NULL; 261 object->charge = 0; 262 object->handle = handle; 263 object->backing_object = NULL; 264 object->backing_object_offset = (vm_ooffset_t) 0; 265 #if VM_NRESERVLEVEL > 0 266 LIST_INIT(&object->rvq); 267 #endif 268 umtx_shm_object_init(object); 269 } 270 271 /* 272 * vm_object_init: 273 * 274 * Initialize the VM objects module. 275 */ 276 void 277 vm_object_init(void) 278 { 279 TAILQ_INIT(&vm_object_list); 280 mtx_init(&vm_object_list_mtx, "vm object_list", NULL, MTX_DEF); 281 282 rw_init(&kernel_object->lock, "kernel vm object"); 283 vm_radix_init(&kernel_object->rtree); 284 _vm_object_allocate(OBJT_PHYS, atop(VM_MAX_KERNEL_ADDRESS - 285 VM_MIN_KERNEL_ADDRESS), OBJ_UNMANAGED, kernel_object, NULL); 286 #if VM_NRESERVLEVEL > 0 287 kernel_object->flags |= OBJ_COLORED; 288 kernel_object->pg_color = (u_short)atop(VM_MIN_KERNEL_ADDRESS); 289 #endif 290 kernel_object->un_pager.phys.ops = &default_phys_pg_ops; 291 292 /* 293 * The lock portion of struct vm_object must be type stable due 294 * to vm_pageout_fallback_object_lock locking a vm object 295 * without holding any references to it. 296 * 297 * paging_in_progress is valid always. Lockless references to 298 * the objects may acquire pip and then check OBJ_DEAD. 299 */ 300 obj_zone = uma_zcreate("VM OBJECT", sizeof (struct vm_object), NULL, 301 #ifdef INVARIANTS 302 vm_object_zdtor, 303 #else 304 NULL, 305 #endif 306 vm_object_zinit, NULL, UMA_ALIGN_PTR, UMA_ZONE_NOFREE); 307 308 vm_radix_zinit(); 309 } 310 311 void 312 vm_object_clear_flag(vm_object_t object, u_short bits) 313 { 314 315 VM_OBJECT_ASSERT_WLOCKED(object); 316 object->flags &= ~bits; 317 } 318 319 /* 320 * Sets the default memory attribute for the specified object. Pages 321 * that are allocated to this object are by default assigned this memory 322 * attribute. 323 * 324 * Presently, this function must be called before any pages are allocated 325 * to the object. In the future, this requirement may be relaxed for 326 * "default" and "swap" objects. 327 */ 328 int 329 vm_object_set_memattr(vm_object_t object, vm_memattr_t memattr) 330 { 331 332 VM_OBJECT_ASSERT_WLOCKED(object); 333 334 if (object->type == OBJT_DEAD) 335 return (KERN_INVALID_ARGUMENT); 336 if (!TAILQ_EMPTY(&object->memq)) 337 return (KERN_FAILURE); 338 339 object->memattr = memattr; 340 return (KERN_SUCCESS); 341 } 342 343 void 344 vm_object_pip_add(vm_object_t object, short i) 345 { 346 347 if (i > 0) 348 blockcount_acquire(&object->paging_in_progress, i); 349 } 350 351 void 352 vm_object_pip_wakeup(vm_object_t object) 353 { 354 355 vm_object_pip_wakeupn(object, 1); 356 } 357 358 void 359 vm_object_pip_wakeupn(vm_object_t object, short i) 360 { 361 362 if (i > 0) 363 blockcount_release(&object->paging_in_progress, i); 364 } 365 366 /* 367 * Atomically drop the object lock and wait for pip to drain. This protects 368 * from sleep/wakeup races due to identity changes. The lock is not re-acquired 369 * on return. 370 */ 371 static void 372 vm_object_pip_sleep(vm_object_t object, const char *waitid) 373 { 374 375 (void)blockcount_sleep(&object->paging_in_progress, &object->lock, 376 waitid, PVM | PDROP); 377 } 378 379 void 380 vm_object_pip_wait(vm_object_t object, const char *waitid) 381 { 382 383 VM_OBJECT_ASSERT_WLOCKED(object); 384 385 blockcount_wait(&object->paging_in_progress, &object->lock, waitid, 386 PVM); 387 } 388 389 void 390 vm_object_pip_wait_unlocked(vm_object_t object, const char *waitid) 391 { 392 393 VM_OBJECT_ASSERT_UNLOCKED(object); 394 395 blockcount_wait(&object->paging_in_progress, NULL, waitid, PVM); 396 } 397 398 /* 399 * vm_object_allocate: 400 * 401 * Returns a new object with the given size. 402 */ 403 vm_object_t 404 vm_object_allocate(objtype_t type, vm_pindex_t size) 405 { 406 vm_object_t object; 407 u_short flags; 408 409 switch (type) { 410 case OBJT_DEAD: 411 panic("vm_object_allocate: can't create OBJT_DEAD"); 412 case OBJT_SWAP: 413 flags = OBJ_COLORED | OBJ_SWAP; 414 break; 415 case OBJT_DEVICE: 416 case OBJT_SG: 417 flags = OBJ_FICTITIOUS | OBJ_UNMANAGED; 418 break; 419 case OBJT_MGTDEVICE: 420 flags = OBJ_FICTITIOUS; 421 break; 422 case OBJT_PHYS: 423 flags = OBJ_UNMANAGED; 424 break; 425 case OBJT_VNODE: 426 flags = 0; 427 break; 428 default: 429 panic("vm_object_allocate: type %d is undefined or dynamic", 430 type); 431 } 432 object = (vm_object_t)uma_zalloc(obj_zone, M_WAITOK); 433 _vm_object_allocate(type, size, flags, object, NULL); 434 435 return (object); 436 } 437 438 vm_object_t 439 vm_object_allocate_dyn(objtype_t dyntype, vm_pindex_t size, u_short flags) 440 { 441 vm_object_t object; 442 443 MPASS(dyntype >= OBJT_FIRST_DYN /* && dyntype < nitems(pagertab) */); 444 object = (vm_object_t)uma_zalloc(obj_zone, M_WAITOK); 445 _vm_object_allocate(dyntype, size, flags, object, NULL); 446 447 return (object); 448 } 449 450 /* 451 * vm_object_allocate_anon: 452 * 453 * Returns a new default object of the given size and marked as 454 * anonymous memory for special split/collapse handling. Color 455 * to be initialized by the caller. 456 */ 457 vm_object_t 458 vm_object_allocate_anon(vm_pindex_t size, vm_object_t backing_object, 459 struct ucred *cred, vm_size_t charge) 460 { 461 vm_object_t handle, object; 462 463 if (backing_object == NULL) 464 handle = NULL; 465 else if ((backing_object->flags & OBJ_ANON) != 0) 466 handle = backing_object->handle; 467 else 468 handle = backing_object; 469 object = uma_zalloc(obj_zone, M_WAITOK); 470 _vm_object_allocate(OBJT_SWAP, size, 471 OBJ_ANON | OBJ_ONEMAPPING | OBJ_SWAP, object, handle); 472 object->cred = cred; 473 object->charge = cred != NULL ? charge : 0; 474 return (object); 475 } 476 477 static void 478 vm_object_reference_vnode(vm_object_t object) 479 { 480 u_int old; 481 482 /* 483 * vnode objects need the lock for the first reference 484 * to serialize with vnode_object_deallocate(). 485 */ 486 if (!refcount_acquire_if_gt(&object->ref_count, 0)) { 487 VM_OBJECT_RLOCK(object); 488 old = refcount_acquire(&object->ref_count); 489 if (object->type == OBJT_VNODE && old == 0) 490 vref(object->handle); 491 VM_OBJECT_RUNLOCK(object); 492 } 493 } 494 495 /* 496 * vm_object_reference: 497 * 498 * Acquires a reference to the given object. 499 */ 500 void 501 vm_object_reference(vm_object_t object) 502 { 503 504 if (object == NULL) 505 return; 506 507 if (object->type == OBJT_VNODE) 508 vm_object_reference_vnode(object); 509 else 510 refcount_acquire(&object->ref_count); 511 KASSERT((object->flags & OBJ_DEAD) == 0, 512 ("vm_object_reference: Referenced dead object.")); 513 } 514 515 /* 516 * vm_object_reference_locked: 517 * 518 * Gets another reference to the given object. 519 * 520 * The object must be locked. 521 */ 522 void 523 vm_object_reference_locked(vm_object_t object) 524 { 525 u_int old; 526 527 VM_OBJECT_ASSERT_LOCKED(object); 528 old = refcount_acquire(&object->ref_count); 529 if (object->type == OBJT_VNODE && old == 0) 530 vref(object->handle); 531 KASSERT((object->flags & OBJ_DEAD) == 0, 532 ("vm_object_reference: Referenced dead object.")); 533 } 534 535 /* 536 * Handle deallocating an object of type OBJT_VNODE. 537 */ 538 static void 539 vm_object_deallocate_vnode(vm_object_t object) 540 { 541 struct vnode *vp = (struct vnode *) object->handle; 542 bool last; 543 544 KASSERT(object->type == OBJT_VNODE, 545 ("vm_object_deallocate_vnode: not a vnode object")); 546 KASSERT(vp != NULL, ("vm_object_deallocate_vnode: missing vp")); 547 548 /* Object lock to protect handle lookup. */ 549 last = refcount_release(&object->ref_count); 550 VM_OBJECT_RUNLOCK(object); 551 552 if (!last) 553 return; 554 555 if (!umtx_shm_vnobj_persistent) 556 umtx_shm_object_terminated(object); 557 558 /* vrele may need the vnode lock. */ 559 vrele(vp); 560 } 561 562 /* 563 * We dropped a reference on an object and discovered that it had a 564 * single remaining shadow. This is a sibling of the reference we 565 * dropped. Attempt to collapse the sibling and backing object. 566 */ 567 static vm_object_t 568 vm_object_deallocate_anon(vm_object_t backing_object) 569 { 570 vm_object_t object; 571 572 /* Fetch the final shadow. */ 573 object = LIST_FIRST(&backing_object->shadow_head); 574 KASSERT(object != NULL && 575 atomic_load_int(&backing_object->shadow_count) == 1, 576 ("vm_object_anon_deallocate: ref_count: %d, shadow_count: %d", 577 backing_object->ref_count, 578 atomic_load_int(&backing_object->shadow_count))); 579 KASSERT((object->flags & OBJ_ANON) != 0, 580 ("invalid shadow object %p", object)); 581 582 if (!VM_OBJECT_TRYWLOCK(object)) { 583 /* 584 * Prevent object from disappearing since we do not have a 585 * reference. 586 */ 587 vm_object_pip_add(object, 1); 588 VM_OBJECT_WUNLOCK(backing_object); 589 VM_OBJECT_WLOCK(object); 590 vm_object_pip_wakeup(object); 591 } else 592 VM_OBJECT_WUNLOCK(backing_object); 593 594 /* 595 * Check for a collapse/terminate race with the last reference holder. 596 */ 597 if ((object->flags & (OBJ_DEAD | OBJ_COLLAPSING)) != 0 || 598 !refcount_acquire_if_not_zero(&object->ref_count)) { 599 VM_OBJECT_WUNLOCK(object); 600 return (NULL); 601 } 602 backing_object = object->backing_object; 603 if (backing_object != NULL && (backing_object->flags & OBJ_ANON) != 0) 604 vm_object_collapse(object); 605 VM_OBJECT_WUNLOCK(object); 606 607 return (object); 608 } 609 610 /* 611 * vm_object_deallocate: 612 * 613 * Release a reference to the specified object, 614 * gained either through a vm_object_allocate 615 * or a vm_object_reference call. When all references 616 * are gone, storage associated with this object 617 * may be relinquished. 618 * 619 * No object may be locked. 620 */ 621 void 622 vm_object_deallocate(vm_object_t object) 623 { 624 vm_object_t temp; 625 bool released; 626 627 while (object != NULL) { 628 /* 629 * If the reference count goes to 0 we start calling 630 * vm_object_terminate() on the object chain. A ref count 631 * of 1 may be a special case depending on the shadow count 632 * being 0 or 1. These cases require a write lock on the 633 * object. 634 */ 635 if ((object->flags & OBJ_ANON) == 0) 636 released = refcount_release_if_gt(&object->ref_count, 1); 637 else 638 released = refcount_release_if_gt(&object->ref_count, 2); 639 if (released) 640 return; 641 642 if (object->type == OBJT_VNODE) { 643 VM_OBJECT_RLOCK(object); 644 if (object->type == OBJT_VNODE) { 645 vm_object_deallocate_vnode(object); 646 return; 647 } 648 VM_OBJECT_RUNLOCK(object); 649 } 650 651 VM_OBJECT_WLOCK(object); 652 KASSERT(object->ref_count > 0, 653 ("vm_object_deallocate: object deallocated too many times: %d", 654 object->type)); 655 656 /* 657 * If this is not the final reference to an anonymous 658 * object we may need to collapse the shadow chain. 659 */ 660 if (!refcount_release(&object->ref_count)) { 661 if (object->ref_count > 1 || 662 atomic_load_int(&object->shadow_count) == 0) { 663 if ((object->flags & OBJ_ANON) != 0 && 664 object->ref_count == 1) 665 vm_object_set_flag(object, 666 OBJ_ONEMAPPING); 667 VM_OBJECT_WUNLOCK(object); 668 return; 669 } 670 671 /* Handle collapsing last ref on anonymous objects. */ 672 object = vm_object_deallocate_anon(object); 673 continue; 674 } 675 676 /* 677 * Handle the final reference to an object. We restart 678 * the loop with the backing object to avoid recursion. 679 */ 680 umtx_shm_object_terminated(object); 681 temp = object->backing_object; 682 if (temp != NULL) { 683 KASSERT(object->type == OBJT_SWAP, 684 ("shadowed tmpfs v_object 2 %p", object)); 685 vm_object_backing_remove(object); 686 } 687 688 KASSERT((object->flags & OBJ_DEAD) == 0, 689 ("vm_object_deallocate: Terminating dead object.")); 690 vm_object_set_flag(object, OBJ_DEAD); 691 vm_object_terminate(object); 692 object = temp; 693 } 694 } 695 696 void 697 vm_object_destroy(vm_object_t object) 698 { 699 uma_zfree(obj_zone, object); 700 } 701 702 static void 703 vm_object_sub_shadow(vm_object_t object) 704 { 705 KASSERT(object->shadow_count >= 1, 706 ("object %p sub_shadow count zero", object)); 707 atomic_subtract_int(&object->shadow_count, 1); 708 } 709 710 static void 711 vm_object_backing_remove_locked(vm_object_t object) 712 { 713 vm_object_t backing_object; 714 715 backing_object = object->backing_object; 716 VM_OBJECT_ASSERT_WLOCKED(object); 717 VM_OBJECT_ASSERT_WLOCKED(backing_object); 718 719 KASSERT((object->flags & OBJ_COLLAPSING) == 0, 720 ("vm_object_backing_remove: Removing collapsing object.")); 721 722 vm_object_sub_shadow(backing_object); 723 if ((object->flags & OBJ_SHADOWLIST) != 0) { 724 LIST_REMOVE(object, shadow_list); 725 vm_object_clear_flag(object, OBJ_SHADOWLIST); 726 } 727 object->backing_object = NULL; 728 } 729 730 static void 731 vm_object_backing_remove(vm_object_t object) 732 { 733 vm_object_t backing_object; 734 735 VM_OBJECT_ASSERT_WLOCKED(object); 736 737 backing_object = object->backing_object; 738 if ((object->flags & OBJ_SHADOWLIST) != 0) { 739 VM_OBJECT_WLOCK(backing_object); 740 vm_object_backing_remove_locked(object); 741 VM_OBJECT_WUNLOCK(backing_object); 742 } else { 743 object->backing_object = NULL; 744 vm_object_sub_shadow(backing_object); 745 } 746 } 747 748 static void 749 vm_object_backing_insert_locked(vm_object_t object, vm_object_t backing_object) 750 { 751 752 VM_OBJECT_ASSERT_WLOCKED(object); 753 754 atomic_add_int(&backing_object->shadow_count, 1); 755 if ((backing_object->flags & OBJ_ANON) != 0) { 756 VM_OBJECT_ASSERT_WLOCKED(backing_object); 757 LIST_INSERT_HEAD(&backing_object->shadow_head, object, 758 shadow_list); 759 vm_object_set_flag(object, OBJ_SHADOWLIST); 760 } 761 object->backing_object = backing_object; 762 } 763 764 static void 765 vm_object_backing_insert(vm_object_t object, vm_object_t backing_object) 766 { 767 768 VM_OBJECT_ASSERT_WLOCKED(object); 769 770 if ((backing_object->flags & OBJ_ANON) != 0) { 771 VM_OBJECT_WLOCK(backing_object); 772 vm_object_backing_insert_locked(object, backing_object); 773 VM_OBJECT_WUNLOCK(backing_object); 774 } else { 775 object->backing_object = backing_object; 776 atomic_add_int(&backing_object->shadow_count, 1); 777 } 778 } 779 780 /* 781 * Insert an object into a backing_object's shadow list with an additional 782 * reference to the backing_object added. 783 */ 784 static void 785 vm_object_backing_insert_ref(vm_object_t object, vm_object_t backing_object) 786 { 787 788 VM_OBJECT_ASSERT_WLOCKED(object); 789 790 if ((backing_object->flags & OBJ_ANON) != 0) { 791 VM_OBJECT_WLOCK(backing_object); 792 KASSERT((backing_object->flags & OBJ_DEAD) == 0, 793 ("shadowing dead anonymous object")); 794 vm_object_reference_locked(backing_object); 795 vm_object_backing_insert_locked(object, backing_object); 796 vm_object_clear_flag(backing_object, OBJ_ONEMAPPING); 797 VM_OBJECT_WUNLOCK(backing_object); 798 } else { 799 vm_object_reference(backing_object); 800 atomic_add_int(&backing_object->shadow_count, 1); 801 object->backing_object = backing_object; 802 } 803 } 804 805 /* 806 * Transfer a backing reference from backing_object to object. 807 */ 808 static void 809 vm_object_backing_transfer(vm_object_t object, vm_object_t backing_object) 810 { 811 vm_object_t new_backing_object; 812 813 /* 814 * Note that the reference to backing_object->backing_object 815 * moves from within backing_object to within object. 816 */ 817 vm_object_backing_remove_locked(object); 818 new_backing_object = backing_object->backing_object; 819 if (new_backing_object == NULL) 820 return; 821 if ((new_backing_object->flags & OBJ_ANON) != 0) { 822 VM_OBJECT_WLOCK(new_backing_object); 823 vm_object_backing_remove_locked(backing_object); 824 vm_object_backing_insert_locked(object, new_backing_object); 825 VM_OBJECT_WUNLOCK(new_backing_object); 826 } else { 827 /* 828 * shadow_count for new_backing_object is left 829 * unchanged, its reference provided by backing_object 830 * is replaced by object. 831 */ 832 object->backing_object = new_backing_object; 833 backing_object->backing_object = NULL; 834 } 835 } 836 837 /* 838 * Wait for a concurrent collapse to settle. 839 */ 840 static void 841 vm_object_collapse_wait(vm_object_t object) 842 { 843 844 VM_OBJECT_ASSERT_WLOCKED(object); 845 846 while ((object->flags & OBJ_COLLAPSING) != 0) { 847 vm_object_pip_wait(object, "vmcolwait"); 848 counter_u64_add(object_collapse_waits, 1); 849 } 850 } 851 852 /* 853 * Waits for a backing object to clear a pending collapse and returns 854 * it locked if it is an ANON object. 855 */ 856 static vm_object_t 857 vm_object_backing_collapse_wait(vm_object_t object) 858 { 859 vm_object_t backing_object; 860 861 VM_OBJECT_ASSERT_WLOCKED(object); 862 863 for (;;) { 864 backing_object = object->backing_object; 865 if (backing_object == NULL || 866 (backing_object->flags & OBJ_ANON) == 0) 867 return (NULL); 868 VM_OBJECT_WLOCK(backing_object); 869 if ((backing_object->flags & (OBJ_DEAD | OBJ_COLLAPSING)) == 0) 870 break; 871 VM_OBJECT_WUNLOCK(object); 872 vm_object_pip_sleep(backing_object, "vmbckwait"); 873 counter_u64_add(object_collapse_waits, 1); 874 VM_OBJECT_WLOCK(object); 875 } 876 return (backing_object); 877 } 878 879 /* 880 * vm_object_terminate_pages removes any remaining pageable pages 881 * from the object and resets the object to an empty state. 882 */ 883 static void 884 vm_object_terminate_pages(vm_object_t object) 885 { 886 vm_page_t p, p_next; 887 888 VM_OBJECT_ASSERT_WLOCKED(object); 889 890 /* 891 * Free any remaining pageable pages. This also removes them from the 892 * paging queues. However, don't free wired pages, just remove them 893 * from the object. Rather than incrementally removing each page from 894 * the object, the page and object are reset to any empty state. 895 */ 896 TAILQ_FOREACH_SAFE(p, &object->memq, listq, p_next) { 897 vm_page_assert_unbusied(p); 898 KASSERT(p->object == object && 899 (p->ref_count & VPRC_OBJREF) != 0, 900 ("vm_object_terminate_pages: page %p is inconsistent", p)); 901 902 p->object = NULL; 903 if (vm_page_drop(p, VPRC_OBJREF) == VPRC_OBJREF) { 904 VM_CNT_INC(v_pfree); 905 vm_page_free(p); 906 } 907 } 908 909 /* 910 * If the object contained any pages, then reset it to an empty state. 911 * None of the object's fields, including "resident_page_count", were 912 * modified by the preceding loop. 913 */ 914 if (object->resident_page_count != 0) { 915 vm_radix_reclaim_allnodes(&object->rtree); 916 TAILQ_INIT(&object->memq); 917 object->resident_page_count = 0; 918 if (object->type == OBJT_VNODE) 919 vdrop(object->handle); 920 } 921 } 922 923 /* 924 * vm_object_terminate actually destroys the specified object, freeing 925 * up all previously used resources. 926 * 927 * The object must be locked. 928 * This routine may block. 929 */ 930 void 931 vm_object_terminate(vm_object_t object) 932 { 933 934 VM_OBJECT_ASSERT_WLOCKED(object); 935 KASSERT((object->flags & OBJ_DEAD) != 0, 936 ("terminating non-dead obj %p", object)); 937 KASSERT((object->flags & OBJ_COLLAPSING) == 0, 938 ("terminating collapsing obj %p", object)); 939 KASSERT(object->backing_object == NULL, 940 ("terminating shadow obj %p", object)); 941 942 /* 943 * Wait for the pageout daemon and other current users to be 944 * done with the object. Note that new paging_in_progress 945 * users can come after this wait, but they must check 946 * OBJ_DEAD flag set (without unlocking the object), and avoid 947 * the object being terminated. 948 */ 949 vm_object_pip_wait(object, "objtrm"); 950 951 KASSERT(object->ref_count == 0, 952 ("vm_object_terminate: object with references, ref_count=%d", 953 object->ref_count)); 954 955 if ((object->flags & OBJ_PG_DTOR) == 0) 956 vm_object_terminate_pages(object); 957 958 #if VM_NRESERVLEVEL > 0 959 if (__predict_false(!LIST_EMPTY(&object->rvq))) 960 vm_reserv_break_all(object); 961 #endif 962 963 KASSERT(object->cred == NULL || (object->flags & OBJ_SWAP) != 0, 964 ("%s: non-swap obj %p has cred", __func__, object)); 965 966 /* 967 * Let the pager know object is dead. 968 */ 969 vm_pager_deallocate(object); 970 VM_OBJECT_WUNLOCK(object); 971 972 vm_object_destroy(object); 973 } 974 975 /* 976 * Make the page read-only so that we can clear the object flags. However, if 977 * this is a nosync mmap then the object is likely to stay dirty so do not 978 * mess with the page and do not clear the object flags. Returns TRUE if the 979 * page should be flushed, and FALSE otherwise. 980 */ 981 static boolean_t 982 vm_object_page_remove_write(vm_page_t p, int flags, boolean_t *allclean) 983 { 984 985 vm_page_assert_busied(p); 986 987 /* 988 * If we have been asked to skip nosync pages and this is a 989 * nosync page, skip it. Note that the object flags were not 990 * cleared in this case so we do not have to set them. 991 */ 992 if ((flags & OBJPC_NOSYNC) != 0 && (p->a.flags & PGA_NOSYNC) != 0) { 993 *allclean = FALSE; 994 return (FALSE); 995 } else { 996 pmap_remove_write(p); 997 return (p->dirty != 0); 998 } 999 } 1000 1001 /* 1002 * vm_object_page_clean 1003 * 1004 * Clean all dirty pages in the specified range of object. Leaves page 1005 * on whatever queue it is currently on. If NOSYNC is set then do not 1006 * write out pages with PGA_NOSYNC set (originally comes from MAP_NOSYNC), 1007 * leaving the object dirty. 1008 * 1009 * For swap objects backing tmpfs regular files, do not flush anything, 1010 * but remove write protection on the mapped pages to update mtime through 1011 * mmaped writes. 1012 * 1013 * When stuffing pages asynchronously, allow clustering. XXX we need a 1014 * synchronous clustering mode implementation. 1015 * 1016 * Odd semantics: if start == end, we clean everything. 1017 * 1018 * The object must be locked. 1019 * 1020 * Returns FALSE if some page from the range was not written, as 1021 * reported by the pager, and TRUE otherwise. 1022 */ 1023 boolean_t 1024 vm_object_page_clean(vm_object_t object, vm_ooffset_t start, vm_ooffset_t end, 1025 int flags) 1026 { 1027 vm_page_t np, p; 1028 vm_pindex_t pi, tend, tstart; 1029 int curgeneration, n, pagerflags; 1030 boolean_t eio, res, allclean; 1031 1032 VM_OBJECT_ASSERT_WLOCKED(object); 1033 1034 if (!vm_object_mightbedirty(object) || object->resident_page_count == 0) 1035 return (TRUE); 1036 1037 pagerflags = (flags & (OBJPC_SYNC | OBJPC_INVAL)) != 0 ? 1038 VM_PAGER_PUT_SYNC : VM_PAGER_CLUSTER_OK; 1039 pagerflags |= (flags & OBJPC_INVAL) != 0 ? VM_PAGER_PUT_INVAL : 0; 1040 1041 tstart = OFF_TO_IDX(start); 1042 tend = (end == 0) ? object->size : OFF_TO_IDX(end + PAGE_MASK); 1043 allclean = tstart == 0 && tend >= object->size; 1044 res = TRUE; 1045 1046 rescan: 1047 curgeneration = object->generation; 1048 1049 for (p = vm_page_find_least(object, tstart); p != NULL; p = np) { 1050 pi = p->pindex; 1051 if (pi >= tend) 1052 break; 1053 np = TAILQ_NEXT(p, listq); 1054 if (vm_page_none_valid(p)) 1055 continue; 1056 if (vm_page_busy_acquire(p, VM_ALLOC_WAITFAIL) == 0) { 1057 if (object->generation != curgeneration && 1058 (flags & OBJPC_SYNC) != 0) 1059 goto rescan; 1060 np = vm_page_find_least(object, pi); 1061 continue; 1062 } 1063 if (!vm_object_page_remove_write(p, flags, &allclean)) { 1064 vm_page_xunbusy(p); 1065 continue; 1066 } 1067 if (object->type == OBJT_VNODE) { 1068 n = vm_object_page_collect_flush(object, p, pagerflags, 1069 flags, &allclean, &eio); 1070 if (eio) { 1071 res = FALSE; 1072 allclean = FALSE; 1073 } 1074 if (object->generation != curgeneration && 1075 (flags & OBJPC_SYNC) != 0) 1076 goto rescan; 1077 1078 /* 1079 * If the VOP_PUTPAGES() did a truncated write, so 1080 * that even the first page of the run is not fully 1081 * written, vm_pageout_flush() returns 0 as the run 1082 * length. Since the condition that caused truncated 1083 * write may be permanent, e.g. exhausted free space, 1084 * accepting n == 0 would cause an infinite loop. 1085 * 1086 * Forwarding the iterator leaves the unwritten page 1087 * behind, but there is not much we can do there if 1088 * filesystem refuses to write it. 1089 */ 1090 if (n == 0) { 1091 n = 1; 1092 allclean = FALSE; 1093 } 1094 } else { 1095 n = 1; 1096 vm_page_xunbusy(p); 1097 } 1098 np = vm_page_find_least(object, pi + n); 1099 } 1100 #if 0 1101 VOP_FSYNC(vp, (pagerflags & VM_PAGER_PUT_SYNC) ? MNT_WAIT : 0); 1102 #endif 1103 1104 /* 1105 * Leave updating cleangeneration for tmpfs objects to tmpfs 1106 * scan. It needs to update mtime, which happens for other 1107 * filesystems during page writeouts. 1108 */ 1109 if (allclean && object->type == OBJT_VNODE) 1110 object->cleangeneration = curgeneration; 1111 return (res); 1112 } 1113 1114 static int 1115 vm_object_page_collect_flush(vm_object_t object, vm_page_t p, int pagerflags, 1116 int flags, boolean_t *allclean, boolean_t *eio) 1117 { 1118 vm_page_t ma[2 * vm_pageout_page_count - 1], tp; 1119 int base, count, runlen; 1120 1121 vm_page_lock_assert(p, MA_NOTOWNED); 1122 vm_page_assert_xbusied(p); 1123 VM_OBJECT_ASSERT_WLOCKED(object); 1124 base = nitems(ma) / 2; 1125 ma[base] = p; 1126 for (count = 1, tp = p; count < vm_pageout_page_count; count++) { 1127 tp = vm_page_next(tp); 1128 if (tp == NULL || vm_page_tryxbusy(tp) == 0) 1129 break; 1130 if (!vm_object_page_remove_write(tp, flags, allclean)) { 1131 vm_page_xunbusy(tp); 1132 break; 1133 } 1134 ma[base + count] = tp; 1135 } 1136 1137 for (tp = p; count < vm_pageout_page_count; count++) { 1138 tp = vm_page_prev(tp); 1139 if (tp == NULL || vm_page_tryxbusy(tp) == 0) 1140 break; 1141 if (!vm_object_page_remove_write(tp, flags, allclean)) { 1142 vm_page_xunbusy(tp); 1143 break; 1144 } 1145 ma[--base] = tp; 1146 } 1147 1148 vm_pageout_flush(&ma[base], count, pagerflags, nitems(ma) / 2 - base, 1149 &runlen, eio); 1150 return (runlen); 1151 } 1152 1153 /* 1154 * Note that there is absolutely no sense in writing out 1155 * anonymous objects, so we track down the vnode object 1156 * to write out. 1157 * We invalidate (remove) all pages from the address space 1158 * for semantic correctness. 1159 * 1160 * If the backing object is a device object with unmanaged pages, then any 1161 * mappings to the specified range of pages must be removed before this 1162 * function is called. 1163 * 1164 * Note: certain anonymous maps, such as MAP_NOSYNC maps, 1165 * may start out with a NULL object. 1166 */ 1167 boolean_t 1168 vm_object_sync(vm_object_t object, vm_ooffset_t offset, vm_size_t size, 1169 boolean_t syncio, boolean_t invalidate) 1170 { 1171 vm_object_t backing_object; 1172 struct vnode *vp; 1173 struct mount *mp; 1174 int error, flags, fsync_after; 1175 boolean_t res; 1176 1177 if (object == NULL) 1178 return (TRUE); 1179 res = TRUE; 1180 error = 0; 1181 VM_OBJECT_WLOCK(object); 1182 while ((backing_object = object->backing_object) != NULL) { 1183 VM_OBJECT_WLOCK(backing_object); 1184 offset += object->backing_object_offset; 1185 VM_OBJECT_WUNLOCK(object); 1186 object = backing_object; 1187 if (object->size < OFF_TO_IDX(offset + size)) 1188 size = IDX_TO_OFF(object->size) - offset; 1189 } 1190 /* 1191 * Flush pages if writing is allowed, invalidate them 1192 * if invalidation requested. Pages undergoing I/O 1193 * will be ignored by vm_object_page_remove(). 1194 * 1195 * We cannot lock the vnode and then wait for paging 1196 * to complete without deadlocking against vm_fault. 1197 * Instead we simply call vm_object_page_remove() and 1198 * allow it to block internally on a page-by-page 1199 * basis when it encounters pages undergoing async 1200 * I/O. 1201 */ 1202 if (object->type == OBJT_VNODE && 1203 vm_object_mightbedirty(object) != 0 && 1204 ((vp = object->handle)->v_vflag & VV_NOSYNC) == 0) { 1205 VM_OBJECT_WUNLOCK(object); 1206 (void)vn_start_write(vp, &mp, V_WAIT); 1207 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY); 1208 if (syncio && !invalidate && offset == 0 && 1209 atop(size) == object->size) { 1210 /* 1211 * If syncing the whole mapping of the file, 1212 * it is faster to schedule all the writes in 1213 * async mode, also allowing the clustering, 1214 * and then wait for i/o to complete. 1215 */ 1216 flags = 0; 1217 fsync_after = TRUE; 1218 } else { 1219 flags = (syncio || invalidate) ? OBJPC_SYNC : 0; 1220 flags |= invalidate ? (OBJPC_SYNC | OBJPC_INVAL) : 0; 1221 fsync_after = FALSE; 1222 } 1223 VM_OBJECT_WLOCK(object); 1224 res = vm_object_page_clean(object, offset, offset + size, 1225 flags); 1226 VM_OBJECT_WUNLOCK(object); 1227 if (fsync_after) { 1228 for (;;) { 1229 error = VOP_FSYNC(vp, MNT_WAIT, curthread); 1230 if (error != ERELOOKUP) 1231 break; 1232 1233 /* 1234 * Allow SU/bufdaemon to handle more 1235 * dependencies in the meantime. 1236 */ 1237 VOP_UNLOCK(vp); 1238 vn_finished_write(mp); 1239 1240 (void)vn_start_write(vp, &mp, V_WAIT); 1241 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY); 1242 } 1243 } 1244 VOP_UNLOCK(vp); 1245 vn_finished_write(mp); 1246 if (error != 0) 1247 res = FALSE; 1248 VM_OBJECT_WLOCK(object); 1249 } 1250 if ((object->type == OBJT_VNODE || 1251 object->type == OBJT_DEVICE) && invalidate) { 1252 if (object->type == OBJT_DEVICE) 1253 /* 1254 * The option OBJPR_NOTMAPPED must be passed here 1255 * because vm_object_page_remove() cannot remove 1256 * unmanaged mappings. 1257 */ 1258 flags = OBJPR_NOTMAPPED; 1259 else if (old_msync) 1260 flags = 0; 1261 else 1262 flags = OBJPR_CLEANONLY; 1263 vm_object_page_remove(object, OFF_TO_IDX(offset), 1264 OFF_TO_IDX(offset + size + PAGE_MASK), flags); 1265 } 1266 VM_OBJECT_WUNLOCK(object); 1267 return (res); 1268 } 1269 1270 /* 1271 * Determine whether the given advice can be applied to the object. Advice is 1272 * not applied to unmanaged pages since they never belong to page queues, and 1273 * since MADV_FREE is destructive, it can apply only to anonymous pages that 1274 * have been mapped at most once. 1275 */ 1276 static bool 1277 vm_object_advice_applies(vm_object_t object, int advice) 1278 { 1279 1280 if ((object->flags & OBJ_UNMANAGED) != 0) 1281 return (false); 1282 if (advice != MADV_FREE) 1283 return (true); 1284 return ((object->flags & (OBJ_ONEMAPPING | OBJ_ANON)) == 1285 (OBJ_ONEMAPPING | OBJ_ANON)); 1286 } 1287 1288 static void 1289 vm_object_madvise_freespace(vm_object_t object, int advice, vm_pindex_t pindex, 1290 vm_size_t size) 1291 { 1292 1293 if (advice == MADV_FREE) 1294 vm_pager_freespace(object, pindex, size); 1295 } 1296 1297 /* 1298 * vm_object_madvise: 1299 * 1300 * Implements the madvise function at the object/page level. 1301 * 1302 * MADV_WILLNEED (any object) 1303 * 1304 * Activate the specified pages if they are resident. 1305 * 1306 * MADV_DONTNEED (any object) 1307 * 1308 * Deactivate the specified pages if they are resident. 1309 * 1310 * MADV_FREE (OBJT_SWAP objects, OBJ_ONEMAPPING only) 1311 * 1312 * Deactivate and clean the specified pages if they are 1313 * resident. This permits the process to reuse the pages 1314 * without faulting or the kernel to reclaim the pages 1315 * without I/O. 1316 */ 1317 void 1318 vm_object_madvise(vm_object_t object, vm_pindex_t pindex, vm_pindex_t end, 1319 int advice) 1320 { 1321 vm_pindex_t tpindex; 1322 vm_object_t backing_object, tobject; 1323 vm_page_t m, tm; 1324 1325 if (object == NULL) 1326 return; 1327 1328 relookup: 1329 VM_OBJECT_WLOCK(object); 1330 if (!vm_object_advice_applies(object, advice)) { 1331 VM_OBJECT_WUNLOCK(object); 1332 return; 1333 } 1334 for (m = vm_page_find_least(object, pindex); pindex < end; pindex++) { 1335 tobject = object; 1336 1337 /* 1338 * If the next page isn't resident in the top-level object, we 1339 * need to search the shadow chain. When applying MADV_FREE, we 1340 * take care to release any swap space used to store 1341 * non-resident pages. 1342 */ 1343 if (m == NULL || pindex < m->pindex) { 1344 /* 1345 * Optimize a common case: if the top-level object has 1346 * no backing object, we can skip over the non-resident 1347 * range in constant time. 1348 */ 1349 if (object->backing_object == NULL) { 1350 tpindex = (m != NULL && m->pindex < end) ? 1351 m->pindex : end; 1352 vm_object_madvise_freespace(object, advice, 1353 pindex, tpindex - pindex); 1354 if ((pindex = tpindex) == end) 1355 break; 1356 goto next_page; 1357 } 1358 1359 tpindex = pindex; 1360 do { 1361 vm_object_madvise_freespace(tobject, advice, 1362 tpindex, 1); 1363 /* 1364 * Prepare to search the next object in the 1365 * chain. 1366 */ 1367 backing_object = tobject->backing_object; 1368 if (backing_object == NULL) 1369 goto next_pindex; 1370 VM_OBJECT_WLOCK(backing_object); 1371 tpindex += 1372 OFF_TO_IDX(tobject->backing_object_offset); 1373 if (tobject != object) 1374 VM_OBJECT_WUNLOCK(tobject); 1375 tobject = backing_object; 1376 if (!vm_object_advice_applies(tobject, advice)) 1377 goto next_pindex; 1378 } while ((tm = vm_page_lookup(tobject, tpindex)) == 1379 NULL); 1380 } else { 1381 next_page: 1382 tm = m; 1383 m = TAILQ_NEXT(m, listq); 1384 } 1385 1386 /* 1387 * If the page is not in a normal state, skip it. The page 1388 * can not be invalidated while the object lock is held. 1389 */ 1390 if (!vm_page_all_valid(tm) || vm_page_wired(tm)) 1391 goto next_pindex; 1392 KASSERT((tm->flags & PG_FICTITIOUS) == 0, 1393 ("vm_object_madvise: page %p is fictitious", tm)); 1394 KASSERT((tm->oflags & VPO_UNMANAGED) == 0, 1395 ("vm_object_madvise: page %p is not managed", tm)); 1396 if (vm_page_tryxbusy(tm) == 0) { 1397 if (object != tobject) 1398 VM_OBJECT_WUNLOCK(object); 1399 if (advice == MADV_WILLNEED) { 1400 /* 1401 * Reference the page before unlocking and 1402 * sleeping so that the page daemon is less 1403 * likely to reclaim it. 1404 */ 1405 vm_page_aflag_set(tm, PGA_REFERENCED); 1406 } 1407 if (!vm_page_busy_sleep(tm, "madvpo", 0)) 1408 VM_OBJECT_WUNLOCK(tobject); 1409 goto relookup; 1410 } 1411 vm_page_advise(tm, advice); 1412 vm_page_xunbusy(tm); 1413 vm_object_madvise_freespace(tobject, advice, tm->pindex, 1); 1414 next_pindex: 1415 if (tobject != object) 1416 VM_OBJECT_WUNLOCK(tobject); 1417 } 1418 VM_OBJECT_WUNLOCK(object); 1419 } 1420 1421 /* 1422 * vm_object_shadow: 1423 * 1424 * Create a new object which is backed by the 1425 * specified existing object range. The source 1426 * object reference is deallocated. 1427 * 1428 * The new object and offset into that object 1429 * are returned in the source parameters. 1430 */ 1431 void 1432 vm_object_shadow(vm_object_t *object, vm_ooffset_t *offset, vm_size_t length, 1433 struct ucred *cred, bool shared) 1434 { 1435 vm_object_t source; 1436 vm_object_t result; 1437 1438 source = *object; 1439 1440 /* 1441 * Don't create the new object if the old object isn't shared. 1442 * 1443 * If we hold the only reference we can guarantee that it won't 1444 * increase while we have the map locked. Otherwise the race is 1445 * harmless and we will end up with an extra shadow object that 1446 * will be collapsed later. 1447 */ 1448 if (source != NULL && source->ref_count == 1 && 1449 (source->flags & OBJ_ANON) != 0) 1450 return; 1451 1452 /* 1453 * Allocate a new object with the given length. 1454 */ 1455 result = vm_object_allocate_anon(atop(length), source, cred, length); 1456 1457 /* 1458 * Store the offset into the source object, and fix up the offset into 1459 * the new object. 1460 */ 1461 result->backing_object_offset = *offset; 1462 1463 if (shared || source != NULL) { 1464 VM_OBJECT_WLOCK(result); 1465 1466 /* 1467 * The new object shadows the source object, adding a 1468 * reference to it. Our caller changes his reference 1469 * to point to the new object, removing a reference to 1470 * the source object. Net result: no change of 1471 * reference count, unless the caller needs to add one 1472 * more reference due to forking a shared map entry. 1473 */ 1474 if (shared) { 1475 vm_object_reference_locked(result); 1476 vm_object_clear_flag(result, OBJ_ONEMAPPING); 1477 } 1478 1479 /* 1480 * Try to optimize the result object's page color when 1481 * shadowing in order to maintain page coloring 1482 * consistency in the combined shadowed object. 1483 */ 1484 if (source != NULL) { 1485 vm_object_backing_insert(result, source); 1486 result->domain = source->domain; 1487 #if VM_NRESERVLEVEL > 0 1488 vm_object_set_flag(result, 1489 (source->flags & OBJ_COLORED)); 1490 result->pg_color = (source->pg_color + 1491 OFF_TO_IDX(*offset)) & ((1 << (VM_NFREEORDER - 1492 1)) - 1); 1493 #endif 1494 } 1495 VM_OBJECT_WUNLOCK(result); 1496 } 1497 1498 /* 1499 * Return the new things 1500 */ 1501 *offset = 0; 1502 *object = result; 1503 } 1504 1505 /* 1506 * vm_object_split: 1507 * 1508 * Split the pages in a map entry into a new object. This affords 1509 * easier removal of unused pages, and keeps object inheritance from 1510 * being a negative impact on memory usage. 1511 */ 1512 void 1513 vm_object_split(vm_map_entry_t entry) 1514 { 1515 vm_page_t m, m_next; 1516 vm_object_t orig_object, new_object, backing_object; 1517 vm_pindex_t idx, offidxstart; 1518 vm_size_t size; 1519 1520 orig_object = entry->object.vm_object; 1521 KASSERT((orig_object->flags & OBJ_ONEMAPPING) != 0, 1522 ("vm_object_split: Splitting object with multiple mappings.")); 1523 if ((orig_object->flags & OBJ_ANON) == 0) 1524 return; 1525 if (orig_object->ref_count <= 1) 1526 return; 1527 VM_OBJECT_WUNLOCK(orig_object); 1528 1529 offidxstart = OFF_TO_IDX(entry->offset); 1530 size = atop(entry->end - entry->start); 1531 1532 new_object = vm_object_allocate_anon(size, orig_object, 1533 orig_object->cred, ptoa(size)); 1534 1535 /* 1536 * We must wait for the orig_object to complete any in-progress 1537 * collapse so that the swap blocks are stable below. The 1538 * additional reference on backing_object by new object will 1539 * prevent further collapse operations until split completes. 1540 */ 1541 VM_OBJECT_WLOCK(orig_object); 1542 vm_object_collapse_wait(orig_object); 1543 1544 /* 1545 * At this point, the new object is still private, so the order in 1546 * which the original and new objects are locked does not matter. 1547 */ 1548 VM_OBJECT_WLOCK(new_object); 1549 new_object->domain = orig_object->domain; 1550 backing_object = orig_object->backing_object; 1551 if (backing_object != NULL) { 1552 vm_object_backing_insert_ref(new_object, backing_object); 1553 new_object->backing_object_offset = 1554 orig_object->backing_object_offset + entry->offset; 1555 } 1556 if (orig_object->cred != NULL) { 1557 crhold(orig_object->cred); 1558 KASSERT(orig_object->charge >= ptoa(size), 1559 ("orig_object->charge < 0")); 1560 orig_object->charge -= ptoa(size); 1561 } 1562 1563 /* 1564 * Mark the split operation so that swap_pager_getpages() knows 1565 * that the object is in transition. 1566 */ 1567 vm_object_set_flag(orig_object, OBJ_SPLIT); 1568 #ifdef INVARIANTS 1569 idx = 0; 1570 #endif 1571 retry: 1572 m = vm_page_find_least(orig_object, offidxstart); 1573 KASSERT(m == NULL || idx <= m->pindex - offidxstart, 1574 ("%s: object %p was repopulated", __func__, orig_object)); 1575 for (; m != NULL && (idx = m->pindex - offidxstart) < size; 1576 m = m_next) { 1577 m_next = TAILQ_NEXT(m, listq); 1578 1579 /* 1580 * We must wait for pending I/O to complete before we can 1581 * rename the page. 1582 * 1583 * We do not have to VM_PROT_NONE the page as mappings should 1584 * not be changed by this operation. 1585 */ 1586 if (vm_page_tryxbusy(m) == 0) { 1587 VM_OBJECT_WUNLOCK(new_object); 1588 if (vm_page_busy_sleep(m, "spltwt", 0)) 1589 VM_OBJECT_WLOCK(orig_object); 1590 VM_OBJECT_WLOCK(new_object); 1591 goto retry; 1592 } 1593 1594 /* 1595 * The page was left invalid. Likely placed there by 1596 * an incomplete fault. Just remove and ignore. 1597 */ 1598 if (vm_page_none_valid(m)) { 1599 if (vm_page_remove(m)) 1600 vm_page_free(m); 1601 continue; 1602 } 1603 1604 /* vm_page_rename() will dirty the page. */ 1605 if (vm_page_rename(m, new_object, idx)) { 1606 vm_page_xunbusy(m); 1607 VM_OBJECT_WUNLOCK(new_object); 1608 VM_OBJECT_WUNLOCK(orig_object); 1609 vm_radix_wait(); 1610 VM_OBJECT_WLOCK(orig_object); 1611 VM_OBJECT_WLOCK(new_object); 1612 goto retry; 1613 } 1614 1615 #if VM_NRESERVLEVEL > 0 1616 /* 1617 * If some of the reservation's allocated pages remain with 1618 * the original object, then transferring the reservation to 1619 * the new object is neither particularly beneficial nor 1620 * particularly harmful as compared to leaving the reservation 1621 * with the original object. If, however, all of the 1622 * reservation's allocated pages are transferred to the new 1623 * object, then transferring the reservation is typically 1624 * beneficial. Determining which of these two cases applies 1625 * would be more costly than unconditionally renaming the 1626 * reservation. 1627 */ 1628 vm_reserv_rename(m, new_object, orig_object, offidxstart); 1629 #endif 1630 } 1631 1632 /* 1633 * swap_pager_copy() can sleep, in which case the orig_object's 1634 * and new_object's locks are released and reacquired. 1635 */ 1636 swap_pager_copy(orig_object, new_object, offidxstart, 0); 1637 1638 TAILQ_FOREACH(m, &new_object->memq, listq) 1639 vm_page_xunbusy(m); 1640 1641 vm_object_clear_flag(orig_object, OBJ_SPLIT); 1642 VM_OBJECT_WUNLOCK(orig_object); 1643 VM_OBJECT_WUNLOCK(new_object); 1644 entry->object.vm_object = new_object; 1645 entry->offset = 0LL; 1646 vm_object_deallocate(orig_object); 1647 VM_OBJECT_WLOCK(new_object); 1648 } 1649 1650 static vm_page_t 1651 vm_object_collapse_scan_wait(vm_object_t object, vm_page_t p) 1652 { 1653 vm_object_t backing_object; 1654 1655 VM_OBJECT_ASSERT_WLOCKED(object); 1656 backing_object = object->backing_object; 1657 VM_OBJECT_ASSERT_WLOCKED(backing_object); 1658 1659 KASSERT(p == NULL || p->object == object || p->object == backing_object, 1660 ("invalid ownership %p %p %p", p, object, backing_object)); 1661 /* The page is only NULL when rename fails. */ 1662 if (p == NULL) { 1663 VM_OBJECT_WUNLOCK(object); 1664 VM_OBJECT_WUNLOCK(backing_object); 1665 vm_radix_wait(); 1666 VM_OBJECT_WLOCK(object); 1667 } else if (p->object == object) { 1668 VM_OBJECT_WUNLOCK(backing_object); 1669 if (vm_page_busy_sleep(p, "vmocol", 0)) 1670 VM_OBJECT_WLOCK(object); 1671 } else { 1672 VM_OBJECT_WUNLOCK(object); 1673 if (!vm_page_busy_sleep(p, "vmocol", 0)) 1674 VM_OBJECT_WUNLOCK(backing_object); 1675 VM_OBJECT_WLOCK(object); 1676 } 1677 VM_OBJECT_WLOCK(backing_object); 1678 return (TAILQ_FIRST(&backing_object->memq)); 1679 } 1680 1681 static bool 1682 vm_object_scan_all_shadowed(vm_object_t object) 1683 { 1684 vm_object_t backing_object; 1685 vm_page_t p, pp; 1686 vm_pindex_t backing_offset_index, new_pindex, pi, ps; 1687 1688 VM_OBJECT_ASSERT_WLOCKED(object); 1689 VM_OBJECT_ASSERT_WLOCKED(object->backing_object); 1690 1691 backing_object = object->backing_object; 1692 1693 if ((backing_object->flags & OBJ_ANON) == 0) 1694 return (false); 1695 1696 pi = backing_offset_index = OFF_TO_IDX(object->backing_object_offset); 1697 p = vm_page_find_least(backing_object, pi); 1698 ps = swap_pager_find_least(backing_object, pi); 1699 1700 /* 1701 * Only check pages inside the parent object's range and 1702 * inside the parent object's mapping of the backing object. 1703 */ 1704 for (;; pi++) { 1705 if (p != NULL && p->pindex < pi) 1706 p = TAILQ_NEXT(p, listq); 1707 if (ps < pi) 1708 ps = swap_pager_find_least(backing_object, pi); 1709 if (p == NULL && ps >= backing_object->size) 1710 break; 1711 else if (p == NULL) 1712 pi = ps; 1713 else 1714 pi = MIN(p->pindex, ps); 1715 1716 new_pindex = pi - backing_offset_index; 1717 if (new_pindex >= object->size) 1718 break; 1719 1720 if (p != NULL) { 1721 /* 1722 * If the backing object page is busy a 1723 * grandparent or older page may still be 1724 * undergoing CoW. It is not safe to collapse 1725 * the backing object until it is quiesced. 1726 */ 1727 if (vm_page_tryxbusy(p) == 0) 1728 return (false); 1729 1730 /* 1731 * We raced with the fault handler that left 1732 * newly allocated invalid page on the object 1733 * queue and retried. 1734 */ 1735 if (!vm_page_all_valid(p)) 1736 goto unbusy_ret; 1737 } 1738 1739 /* 1740 * See if the parent has the page or if the parent's object 1741 * pager has the page. If the parent has the page but the page 1742 * is not valid, the parent's object pager must have the page. 1743 * 1744 * If this fails, the parent does not completely shadow the 1745 * object and we might as well give up now. 1746 */ 1747 pp = vm_page_lookup(object, new_pindex); 1748 1749 /* 1750 * The valid check here is stable due to object lock 1751 * being required to clear valid and initiate paging. 1752 * Busy of p disallows fault handler to validate pp. 1753 */ 1754 if ((pp == NULL || vm_page_none_valid(pp)) && 1755 !vm_pager_has_page(object, new_pindex, NULL, NULL)) 1756 goto unbusy_ret; 1757 if (p != NULL) 1758 vm_page_xunbusy(p); 1759 } 1760 return (true); 1761 1762 unbusy_ret: 1763 if (p != NULL) 1764 vm_page_xunbusy(p); 1765 return (false); 1766 } 1767 1768 static void 1769 vm_object_collapse_scan(vm_object_t object) 1770 { 1771 vm_object_t backing_object; 1772 vm_page_t next, p, pp; 1773 vm_pindex_t backing_offset_index, new_pindex; 1774 1775 VM_OBJECT_ASSERT_WLOCKED(object); 1776 VM_OBJECT_ASSERT_WLOCKED(object->backing_object); 1777 1778 backing_object = object->backing_object; 1779 backing_offset_index = OFF_TO_IDX(object->backing_object_offset); 1780 1781 /* 1782 * Our scan 1783 */ 1784 for (p = TAILQ_FIRST(&backing_object->memq); p != NULL; p = next) { 1785 next = TAILQ_NEXT(p, listq); 1786 new_pindex = p->pindex - backing_offset_index; 1787 1788 /* 1789 * Check for busy page 1790 */ 1791 if (vm_page_tryxbusy(p) == 0) { 1792 next = vm_object_collapse_scan_wait(object, p); 1793 continue; 1794 } 1795 1796 KASSERT(object->backing_object == backing_object, 1797 ("vm_object_collapse_scan: backing object mismatch %p != %p", 1798 object->backing_object, backing_object)); 1799 KASSERT(p->object == backing_object, 1800 ("vm_object_collapse_scan: object mismatch %p != %p", 1801 p->object, backing_object)); 1802 1803 if (p->pindex < backing_offset_index || 1804 new_pindex >= object->size) { 1805 vm_pager_freespace(backing_object, p->pindex, 1); 1806 1807 KASSERT(!pmap_page_is_mapped(p), 1808 ("freeing mapped page %p", p)); 1809 if (vm_page_remove(p)) 1810 vm_page_free(p); 1811 continue; 1812 } 1813 1814 if (!vm_page_all_valid(p)) { 1815 KASSERT(!pmap_page_is_mapped(p), 1816 ("freeing mapped page %p", p)); 1817 if (vm_page_remove(p)) 1818 vm_page_free(p); 1819 continue; 1820 } 1821 1822 pp = vm_page_lookup(object, new_pindex); 1823 if (pp != NULL && vm_page_tryxbusy(pp) == 0) { 1824 vm_page_xunbusy(p); 1825 /* 1826 * The page in the parent is busy and possibly not 1827 * (yet) valid. Until its state is finalized by the 1828 * busy bit owner, we can't tell whether it shadows the 1829 * original page. 1830 */ 1831 next = vm_object_collapse_scan_wait(object, pp); 1832 continue; 1833 } 1834 1835 if (pp != NULL && vm_page_none_valid(pp)) { 1836 /* 1837 * The page was invalid in the parent. Likely placed 1838 * there by an incomplete fault. Just remove and 1839 * ignore. p can replace it. 1840 */ 1841 if (vm_page_remove(pp)) 1842 vm_page_free(pp); 1843 pp = NULL; 1844 } 1845 1846 if (pp != NULL || vm_pager_has_page(object, new_pindex, NULL, 1847 NULL)) { 1848 /* 1849 * The page already exists in the parent OR swap exists 1850 * for this location in the parent. Leave the parent's 1851 * page alone. Destroy the original page from the 1852 * backing object. 1853 */ 1854 vm_pager_freespace(backing_object, p->pindex, 1); 1855 KASSERT(!pmap_page_is_mapped(p), 1856 ("freeing mapped page %p", p)); 1857 if (vm_page_remove(p)) 1858 vm_page_free(p); 1859 if (pp != NULL) 1860 vm_page_xunbusy(pp); 1861 continue; 1862 } 1863 1864 /* 1865 * Page does not exist in parent, rename the page from the 1866 * backing object to the main object. 1867 * 1868 * If the page was mapped to a process, it can remain mapped 1869 * through the rename. vm_page_rename() will dirty the page. 1870 */ 1871 if (vm_page_rename(p, object, new_pindex)) { 1872 vm_page_xunbusy(p); 1873 next = vm_object_collapse_scan_wait(object, NULL); 1874 continue; 1875 } 1876 1877 /* Use the old pindex to free the right page. */ 1878 vm_pager_freespace(backing_object, new_pindex + 1879 backing_offset_index, 1); 1880 1881 #if VM_NRESERVLEVEL > 0 1882 /* 1883 * Rename the reservation. 1884 */ 1885 vm_reserv_rename(p, object, backing_object, 1886 backing_offset_index); 1887 #endif 1888 vm_page_xunbusy(p); 1889 } 1890 return; 1891 } 1892 1893 /* 1894 * vm_object_collapse: 1895 * 1896 * Collapse an object with the object backing it. 1897 * Pages in the backing object are moved into the 1898 * parent, and the backing object is deallocated. 1899 */ 1900 void 1901 vm_object_collapse(vm_object_t object) 1902 { 1903 vm_object_t backing_object, new_backing_object; 1904 1905 VM_OBJECT_ASSERT_WLOCKED(object); 1906 1907 while (TRUE) { 1908 KASSERT((object->flags & (OBJ_DEAD | OBJ_ANON)) == OBJ_ANON, 1909 ("collapsing invalid object")); 1910 1911 /* 1912 * Wait for the backing_object to finish any pending 1913 * collapse so that the caller sees the shortest possible 1914 * shadow chain. 1915 */ 1916 backing_object = vm_object_backing_collapse_wait(object); 1917 if (backing_object == NULL) 1918 return; 1919 1920 KASSERT(object->ref_count > 0 && 1921 object->ref_count > atomic_load_int(&object->shadow_count), 1922 ("collapse with invalid ref %d or shadow %d count.", 1923 object->ref_count, atomic_load_int(&object->shadow_count))); 1924 KASSERT((backing_object->flags & 1925 (OBJ_COLLAPSING | OBJ_DEAD)) == 0, 1926 ("vm_object_collapse: Backing object already collapsing.")); 1927 KASSERT((object->flags & (OBJ_COLLAPSING | OBJ_DEAD)) == 0, 1928 ("vm_object_collapse: object is already collapsing.")); 1929 1930 /* 1931 * We know that we can either collapse the backing object if 1932 * the parent is the only reference to it, or (perhaps) have 1933 * the parent bypass the object if the parent happens to shadow 1934 * all the resident pages in the entire backing object. 1935 */ 1936 if (backing_object->ref_count == 1) { 1937 KASSERT(atomic_load_int(&backing_object->shadow_count) 1938 == 1, 1939 ("vm_object_collapse: shadow_count: %d", 1940 atomic_load_int(&backing_object->shadow_count))); 1941 vm_object_pip_add(object, 1); 1942 vm_object_set_flag(object, OBJ_COLLAPSING); 1943 vm_object_pip_add(backing_object, 1); 1944 vm_object_set_flag(backing_object, OBJ_DEAD); 1945 1946 /* 1947 * If there is exactly one reference to the backing 1948 * object, we can collapse it into the parent. 1949 */ 1950 vm_object_collapse_scan(object); 1951 1952 /* 1953 * Move the pager from backing_object to object. 1954 * 1955 * swap_pager_copy() can sleep, in which case the 1956 * backing_object's and object's locks are released and 1957 * reacquired. 1958 */ 1959 swap_pager_copy(backing_object, object, 1960 OFF_TO_IDX(object->backing_object_offset), TRUE); 1961 1962 /* 1963 * Object now shadows whatever backing_object did. 1964 */ 1965 vm_object_clear_flag(object, OBJ_COLLAPSING); 1966 vm_object_backing_transfer(object, backing_object); 1967 object->backing_object_offset += 1968 backing_object->backing_object_offset; 1969 VM_OBJECT_WUNLOCK(object); 1970 vm_object_pip_wakeup(object); 1971 1972 /* 1973 * Discard backing_object. 1974 * 1975 * Since the backing object has no pages, no pager left, 1976 * and no object references within it, all that is 1977 * necessary is to dispose of it. 1978 */ 1979 KASSERT(backing_object->ref_count == 1, ( 1980 "backing_object %p was somehow re-referenced during collapse!", 1981 backing_object)); 1982 vm_object_pip_wakeup(backing_object); 1983 (void)refcount_release(&backing_object->ref_count); 1984 umtx_shm_object_terminated(backing_object); 1985 vm_object_terminate(backing_object); 1986 counter_u64_add(object_collapses, 1); 1987 VM_OBJECT_WLOCK(object); 1988 } else { 1989 /* 1990 * If we do not entirely shadow the backing object, 1991 * there is nothing we can do so we give up. 1992 * 1993 * The object lock and backing_object lock must not 1994 * be dropped during this sequence. 1995 */ 1996 if (!vm_object_scan_all_shadowed(object)) { 1997 VM_OBJECT_WUNLOCK(backing_object); 1998 break; 1999 } 2000 2001 /* 2002 * Make the parent shadow the next object in the 2003 * chain. Deallocating backing_object will not remove 2004 * it, since its reference count is at least 2. 2005 */ 2006 vm_object_backing_remove_locked(object); 2007 new_backing_object = backing_object->backing_object; 2008 if (new_backing_object != NULL) { 2009 vm_object_backing_insert_ref(object, 2010 new_backing_object); 2011 object->backing_object_offset += 2012 backing_object->backing_object_offset; 2013 } 2014 2015 /* 2016 * Drop the reference count on backing_object. Since 2017 * its ref_count was at least 2, it will not vanish. 2018 */ 2019 (void)refcount_release(&backing_object->ref_count); 2020 KASSERT(backing_object->ref_count >= 1, ( 2021 "backing_object %p was somehow dereferenced during collapse!", 2022 backing_object)); 2023 VM_OBJECT_WUNLOCK(backing_object); 2024 counter_u64_add(object_bypasses, 1); 2025 } 2026 2027 /* 2028 * Try again with this object's new backing object. 2029 */ 2030 } 2031 } 2032 2033 /* 2034 * vm_object_page_remove: 2035 * 2036 * For the given object, either frees or invalidates each of the 2037 * specified pages. In general, a page is freed. However, if a page is 2038 * wired for any reason other than the existence of a managed, wired 2039 * mapping, then it may be invalidated but not removed from the object. 2040 * Pages are specified by the given range ["start", "end") and the option 2041 * OBJPR_CLEANONLY. As a special case, if "end" is zero, then the range 2042 * extends from "start" to the end of the object. If the option 2043 * OBJPR_CLEANONLY is specified, then only the non-dirty pages within the 2044 * specified range are affected. If the option OBJPR_NOTMAPPED is 2045 * specified, then the pages within the specified range must have no 2046 * mappings. Otherwise, if this option is not specified, any mappings to 2047 * the specified pages are removed before the pages are freed or 2048 * invalidated. 2049 * 2050 * In general, this operation should only be performed on objects that 2051 * contain managed pages. There are, however, two exceptions. First, it 2052 * is performed on the kernel and kmem objects by vm_map_entry_delete(). 2053 * Second, it is used by msync(..., MS_INVALIDATE) to invalidate device- 2054 * backed pages. In both of these cases, the option OBJPR_CLEANONLY must 2055 * not be specified and the option OBJPR_NOTMAPPED must be specified. 2056 * 2057 * The object must be locked. 2058 */ 2059 void 2060 vm_object_page_remove(vm_object_t object, vm_pindex_t start, vm_pindex_t end, 2061 int options) 2062 { 2063 vm_page_t p, next; 2064 2065 VM_OBJECT_ASSERT_WLOCKED(object); 2066 KASSERT((object->flags & OBJ_UNMANAGED) == 0 || 2067 (options & (OBJPR_CLEANONLY | OBJPR_NOTMAPPED)) == OBJPR_NOTMAPPED, 2068 ("vm_object_page_remove: illegal options for object %p", object)); 2069 if (object->resident_page_count == 0) 2070 return; 2071 vm_object_pip_add(object, 1); 2072 again: 2073 p = vm_page_find_least(object, start); 2074 2075 /* 2076 * Here, the variable "p" is either (1) the page with the least pindex 2077 * greater than or equal to the parameter "start" or (2) NULL. 2078 */ 2079 for (; p != NULL && (p->pindex < end || end == 0); p = next) { 2080 next = TAILQ_NEXT(p, listq); 2081 2082 /* 2083 * Skip invalid pages if asked to do so. Try to avoid acquiring 2084 * the busy lock, as some consumers rely on this to avoid 2085 * deadlocks. 2086 * 2087 * A thread may concurrently transition the page from invalid to 2088 * valid using only the busy lock, so the result of this check 2089 * is immediately stale. It is up to consumers to handle this, 2090 * for instance by ensuring that all invalid->valid transitions 2091 * happen with a mutex held, as may be possible for a 2092 * filesystem. 2093 */ 2094 if ((options & OBJPR_VALIDONLY) != 0 && vm_page_none_valid(p)) 2095 continue; 2096 2097 /* 2098 * If the page is wired for any reason besides the existence 2099 * of managed, wired mappings, then it cannot be freed. For 2100 * example, fictitious pages, which represent device memory, 2101 * are inherently wired and cannot be freed. They can, 2102 * however, be invalidated if the option OBJPR_CLEANONLY is 2103 * not specified. 2104 */ 2105 if (vm_page_tryxbusy(p) == 0) { 2106 if (vm_page_busy_sleep(p, "vmopar", 0)) 2107 VM_OBJECT_WLOCK(object); 2108 goto again; 2109 } 2110 if ((options & OBJPR_VALIDONLY) != 0 && vm_page_none_valid(p)) { 2111 vm_page_xunbusy(p); 2112 continue; 2113 } 2114 if (vm_page_wired(p)) { 2115 wired: 2116 if ((options & OBJPR_NOTMAPPED) == 0 && 2117 object->ref_count != 0) 2118 pmap_remove_all(p); 2119 if ((options & OBJPR_CLEANONLY) == 0) { 2120 vm_page_invalid(p); 2121 vm_page_undirty(p); 2122 } 2123 vm_page_xunbusy(p); 2124 continue; 2125 } 2126 KASSERT((p->flags & PG_FICTITIOUS) == 0, 2127 ("vm_object_page_remove: page %p is fictitious", p)); 2128 if ((options & OBJPR_CLEANONLY) != 0 && 2129 !vm_page_none_valid(p)) { 2130 if ((options & OBJPR_NOTMAPPED) == 0 && 2131 object->ref_count != 0 && 2132 !vm_page_try_remove_write(p)) 2133 goto wired; 2134 if (p->dirty != 0) { 2135 vm_page_xunbusy(p); 2136 continue; 2137 } 2138 } 2139 if ((options & OBJPR_NOTMAPPED) == 0 && 2140 object->ref_count != 0 && !vm_page_try_remove_all(p)) 2141 goto wired; 2142 vm_page_free(p); 2143 } 2144 vm_object_pip_wakeup(object); 2145 2146 vm_pager_freespace(object, start, (end == 0 ? object->size : end) - 2147 start); 2148 } 2149 2150 /* 2151 * vm_object_page_noreuse: 2152 * 2153 * For the given object, attempt to move the specified pages to 2154 * the head of the inactive queue. This bypasses regular LRU 2155 * operation and allows the pages to be reused quickly under memory 2156 * pressure. If a page is wired for any reason, then it will not 2157 * be queued. Pages are specified by the range ["start", "end"). 2158 * As a special case, if "end" is zero, then the range extends from 2159 * "start" to the end of the object. 2160 * 2161 * This operation should only be performed on objects that 2162 * contain non-fictitious, managed pages. 2163 * 2164 * The object must be locked. 2165 */ 2166 void 2167 vm_object_page_noreuse(vm_object_t object, vm_pindex_t start, vm_pindex_t end) 2168 { 2169 vm_page_t p, next; 2170 2171 VM_OBJECT_ASSERT_LOCKED(object); 2172 KASSERT((object->flags & (OBJ_FICTITIOUS | OBJ_UNMANAGED)) == 0, 2173 ("vm_object_page_noreuse: illegal object %p", object)); 2174 if (object->resident_page_count == 0) 2175 return; 2176 p = vm_page_find_least(object, start); 2177 2178 /* 2179 * Here, the variable "p" is either (1) the page with the least pindex 2180 * greater than or equal to the parameter "start" or (2) NULL. 2181 */ 2182 for (; p != NULL && (p->pindex < end || end == 0); p = next) { 2183 next = TAILQ_NEXT(p, listq); 2184 vm_page_deactivate_noreuse(p); 2185 } 2186 } 2187 2188 /* 2189 * Populate the specified range of the object with valid pages. Returns 2190 * TRUE if the range is successfully populated and FALSE otherwise. 2191 * 2192 * Note: This function should be optimized to pass a larger array of 2193 * pages to vm_pager_get_pages() before it is applied to a non- 2194 * OBJT_DEVICE object. 2195 * 2196 * The object must be locked. 2197 */ 2198 boolean_t 2199 vm_object_populate(vm_object_t object, vm_pindex_t start, vm_pindex_t end) 2200 { 2201 vm_page_t m; 2202 vm_pindex_t pindex; 2203 int rv; 2204 2205 VM_OBJECT_ASSERT_WLOCKED(object); 2206 for (pindex = start; pindex < end; pindex++) { 2207 rv = vm_page_grab_valid(&m, object, pindex, VM_ALLOC_NORMAL); 2208 if (rv != VM_PAGER_OK) 2209 break; 2210 2211 /* 2212 * Keep "m" busy because a subsequent iteration may unlock 2213 * the object. 2214 */ 2215 } 2216 if (pindex > start) { 2217 m = vm_page_lookup(object, start); 2218 while (m != NULL && m->pindex < pindex) { 2219 vm_page_xunbusy(m); 2220 m = TAILQ_NEXT(m, listq); 2221 } 2222 } 2223 return (pindex == end); 2224 } 2225 2226 /* 2227 * Routine: vm_object_coalesce 2228 * Function: Coalesces two objects backing up adjoining 2229 * regions of memory into a single object. 2230 * 2231 * returns TRUE if objects were combined. 2232 * 2233 * NOTE: Only works at the moment if the second object is NULL - 2234 * if it's not, which object do we lock first? 2235 * 2236 * Parameters: 2237 * prev_object First object to coalesce 2238 * prev_offset Offset into prev_object 2239 * prev_size Size of reference to prev_object 2240 * next_size Size of reference to the second object 2241 * reserved Indicator that extension region has 2242 * swap accounted for 2243 * 2244 * Conditions: 2245 * The object must *not* be locked. 2246 */ 2247 boolean_t 2248 vm_object_coalesce(vm_object_t prev_object, vm_ooffset_t prev_offset, 2249 vm_size_t prev_size, vm_size_t next_size, boolean_t reserved) 2250 { 2251 vm_pindex_t next_pindex; 2252 2253 if (prev_object == NULL) 2254 return (TRUE); 2255 if ((prev_object->flags & OBJ_ANON) == 0) 2256 return (FALSE); 2257 2258 VM_OBJECT_WLOCK(prev_object); 2259 /* 2260 * Try to collapse the object first. 2261 */ 2262 vm_object_collapse(prev_object); 2263 2264 /* 2265 * Can't coalesce if: . more than one reference . paged out . shadows 2266 * another object . has a copy elsewhere (any of which mean that the 2267 * pages not mapped to prev_entry may be in use anyway) 2268 */ 2269 if (prev_object->backing_object != NULL) { 2270 VM_OBJECT_WUNLOCK(prev_object); 2271 return (FALSE); 2272 } 2273 2274 prev_size >>= PAGE_SHIFT; 2275 next_size >>= PAGE_SHIFT; 2276 next_pindex = OFF_TO_IDX(prev_offset) + prev_size; 2277 2278 if (prev_object->ref_count > 1 && 2279 prev_object->size != next_pindex && 2280 (prev_object->flags & OBJ_ONEMAPPING) == 0) { 2281 VM_OBJECT_WUNLOCK(prev_object); 2282 return (FALSE); 2283 } 2284 2285 /* 2286 * Account for the charge. 2287 */ 2288 if (prev_object->cred != NULL) { 2289 /* 2290 * If prev_object was charged, then this mapping, 2291 * although not charged now, may become writable 2292 * later. Non-NULL cred in the object would prevent 2293 * swap reservation during enabling of the write 2294 * access, so reserve swap now. Failed reservation 2295 * cause allocation of the separate object for the map 2296 * entry, and swap reservation for this entry is 2297 * managed in appropriate time. 2298 */ 2299 if (!reserved && !swap_reserve_by_cred(ptoa(next_size), 2300 prev_object->cred)) { 2301 VM_OBJECT_WUNLOCK(prev_object); 2302 return (FALSE); 2303 } 2304 prev_object->charge += ptoa(next_size); 2305 } 2306 2307 /* 2308 * Remove any pages that may still be in the object from a previous 2309 * deallocation. 2310 */ 2311 if (next_pindex < prev_object->size) { 2312 vm_object_page_remove(prev_object, next_pindex, next_pindex + 2313 next_size, 0); 2314 #if 0 2315 if (prev_object->cred != NULL) { 2316 KASSERT(prev_object->charge >= 2317 ptoa(prev_object->size - next_pindex), 2318 ("object %p overcharged 1 %jx %jx", prev_object, 2319 (uintmax_t)next_pindex, (uintmax_t)next_size)); 2320 prev_object->charge -= ptoa(prev_object->size - 2321 next_pindex); 2322 } 2323 #endif 2324 } 2325 2326 /* 2327 * Extend the object if necessary. 2328 */ 2329 if (next_pindex + next_size > prev_object->size) 2330 prev_object->size = next_pindex + next_size; 2331 2332 VM_OBJECT_WUNLOCK(prev_object); 2333 return (TRUE); 2334 } 2335 2336 void 2337 vm_object_set_writeable_dirty_(vm_object_t object) 2338 { 2339 atomic_add_int(&object->generation, 1); 2340 } 2341 2342 bool 2343 vm_object_mightbedirty_(vm_object_t object) 2344 { 2345 return (object->generation != object->cleangeneration); 2346 } 2347 2348 /* 2349 * vm_object_unwire: 2350 * 2351 * For each page offset within the specified range of the given object, 2352 * find the highest-level page in the shadow chain and unwire it. A page 2353 * must exist at every page offset, and the highest-level page must be 2354 * wired. 2355 */ 2356 void 2357 vm_object_unwire(vm_object_t object, vm_ooffset_t offset, vm_size_t length, 2358 uint8_t queue) 2359 { 2360 vm_object_t tobject, t1object; 2361 vm_page_t m, tm; 2362 vm_pindex_t end_pindex, pindex, tpindex; 2363 int depth, locked_depth; 2364 2365 KASSERT((offset & PAGE_MASK) == 0, 2366 ("vm_object_unwire: offset is not page aligned")); 2367 KASSERT((length & PAGE_MASK) == 0, 2368 ("vm_object_unwire: length is not a multiple of PAGE_SIZE")); 2369 /* The wired count of a fictitious page never changes. */ 2370 if ((object->flags & OBJ_FICTITIOUS) != 0) 2371 return; 2372 pindex = OFF_TO_IDX(offset); 2373 end_pindex = pindex + atop(length); 2374 again: 2375 locked_depth = 1; 2376 VM_OBJECT_RLOCK(object); 2377 m = vm_page_find_least(object, pindex); 2378 while (pindex < end_pindex) { 2379 if (m == NULL || pindex < m->pindex) { 2380 /* 2381 * The first object in the shadow chain doesn't 2382 * contain a page at the current index. Therefore, 2383 * the page must exist in a backing object. 2384 */ 2385 tobject = object; 2386 tpindex = pindex; 2387 depth = 0; 2388 do { 2389 tpindex += 2390 OFF_TO_IDX(tobject->backing_object_offset); 2391 tobject = tobject->backing_object; 2392 KASSERT(tobject != NULL, 2393 ("vm_object_unwire: missing page")); 2394 if ((tobject->flags & OBJ_FICTITIOUS) != 0) 2395 goto next_page; 2396 depth++; 2397 if (depth == locked_depth) { 2398 locked_depth++; 2399 VM_OBJECT_RLOCK(tobject); 2400 } 2401 } while ((tm = vm_page_lookup(tobject, tpindex)) == 2402 NULL); 2403 } else { 2404 tm = m; 2405 m = TAILQ_NEXT(m, listq); 2406 } 2407 if (vm_page_trysbusy(tm) == 0) { 2408 for (tobject = object; locked_depth >= 1; 2409 locked_depth--) { 2410 t1object = tobject->backing_object; 2411 if (tm->object != tobject) 2412 VM_OBJECT_RUNLOCK(tobject); 2413 tobject = t1object; 2414 } 2415 tobject = tm->object; 2416 if (!vm_page_busy_sleep(tm, "unwbo", 2417 VM_ALLOC_IGN_SBUSY)) 2418 VM_OBJECT_RUNLOCK(tobject); 2419 goto again; 2420 } 2421 vm_page_unwire(tm, queue); 2422 vm_page_sunbusy(tm); 2423 next_page: 2424 pindex++; 2425 } 2426 /* Release the accumulated object locks. */ 2427 for (tobject = object; locked_depth >= 1; locked_depth--) { 2428 t1object = tobject->backing_object; 2429 VM_OBJECT_RUNLOCK(tobject); 2430 tobject = t1object; 2431 } 2432 } 2433 2434 /* 2435 * Return the vnode for the given object, or NULL if none exists. 2436 * For tmpfs objects, the function may return NULL if there is 2437 * no vnode allocated at the time of the call. 2438 */ 2439 struct vnode * 2440 vm_object_vnode(vm_object_t object) 2441 { 2442 struct vnode *vp; 2443 2444 VM_OBJECT_ASSERT_LOCKED(object); 2445 vm_pager_getvp(object, &vp, NULL); 2446 return (vp); 2447 } 2448 2449 /* 2450 * Busy the vm object. This prevents new pages belonging to the object from 2451 * becoming busy. Existing pages persist as busy. Callers are responsible 2452 * for checking page state before proceeding. 2453 */ 2454 void 2455 vm_object_busy(vm_object_t obj) 2456 { 2457 2458 VM_OBJECT_ASSERT_LOCKED(obj); 2459 2460 blockcount_acquire(&obj->busy, 1); 2461 /* The fence is required to order loads of page busy. */ 2462 atomic_thread_fence_acq_rel(); 2463 } 2464 2465 void 2466 vm_object_unbusy(vm_object_t obj) 2467 { 2468 2469 blockcount_release(&obj->busy, 1); 2470 } 2471 2472 void 2473 vm_object_busy_wait(vm_object_t obj, const char *wmesg) 2474 { 2475 2476 VM_OBJECT_ASSERT_UNLOCKED(obj); 2477 2478 (void)blockcount_sleep(&obj->busy, NULL, wmesg, PVM); 2479 } 2480 2481 /* 2482 * This function aims to determine if the object is mapped, 2483 * specifically, if it is referenced by a vm_map_entry. Because 2484 * objects occasionally acquire transient references that do not 2485 * represent a mapping, the method used here is inexact. However, it 2486 * has very low overhead and is good enough for the advisory 2487 * vm.vmtotal sysctl. 2488 */ 2489 bool 2490 vm_object_is_active(vm_object_t obj) 2491 { 2492 2493 return (obj->ref_count > atomic_load_int(&obj->shadow_count)); 2494 } 2495 2496 static int 2497 vm_object_list_handler(struct sysctl_req *req, bool swap_only) 2498 { 2499 struct kinfo_vmobject *kvo; 2500 char *fullpath, *freepath; 2501 struct vnode *vp; 2502 struct vattr va; 2503 vm_object_t obj; 2504 vm_page_t m; 2505 u_long sp; 2506 int count, error; 2507 bool want_path; 2508 2509 if (req->oldptr == NULL) { 2510 /* 2511 * If an old buffer has not been provided, generate an 2512 * estimate of the space needed for a subsequent call. 2513 */ 2514 mtx_lock(&vm_object_list_mtx); 2515 count = 0; 2516 TAILQ_FOREACH(obj, &vm_object_list, object_list) { 2517 if (obj->type == OBJT_DEAD) 2518 continue; 2519 count++; 2520 } 2521 mtx_unlock(&vm_object_list_mtx); 2522 return (SYSCTL_OUT(req, NULL, sizeof(struct kinfo_vmobject) * 2523 count * 11 / 10)); 2524 } 2525 2526 want_path = !(swap_only || jailed(curthread->td_ucred)); 2527 kvo = malloc(sizeof(*kvo), M_TEMP, M_WAITOK | M_ZERO); 2528 error = 0; 2529 2530 /* 2531 * VM objects are type stable and are never removed from the 2532 * list once added. This allows us to safely read obj->object_list 2533 * after reacquiring the VM object lock. 2534 */ 2535 mtx_lock(&vm_object_list_mtx); 2536 TAILQ_FOREACH(obj, &vm_object_list, object_list) { 2537 if (obj->type == OBJT_DEAD || 2538 (swap_only && (obj->flags & (OBJ_ANON | OBJ_SWAP)) == 0)) 2539 continue; 2540 VM_OBJECT_RLOCK(obj); 2541 if (obj->type == OBJT_DEAD || 2542 (swap_only && (obj->flags & (OBJ_ANON | OBJ_SWAP)) == 0)) { 2543 VM_OBJECT_RUNLOCK(obj); 2544 continue; 2545 } 2546 mtx_unlock(&vm_object_list_mtx); 2547 kvo->kvo_size = ptoa(obj->size); 2548 kvo->kvo_resident = obj->resident_page_count; 2549 kvo->kvo_ref_count = obj->ref_count; 2550 kvo->kvo_shadow_count = atomic_load_int(&obj->shadow_count); 2551 kvo->kvo_memattr = obj->memattr; 2552 kvo->kvo_active = 0; 2553 kvo->kvo_inactive = 0; 2554 if (!swap_only) { 2555 TAILQ_FOREACH(m, &obj->memq, listq) { 2556 /* 2557 * A page may belong to the object but be 2558 * dequeued and set to PQ_NONE while the 2559 * object lock is not held. This makes the 2560 * reads of m->queue below racy, and we do not 2561 * count pages set to PQ_NONE. However, this 2562 * sysctl is only meant to give an 2563 * approximation of the system anyway. 2564 */ 2565 if (m->a.queue == PQ_ACTIVE) 2566 kvo->kvo_active++; 2567 else if (m->a.queue == PQ_INACTIVE) 2568 kvo->kvo_inactive++; 2569 } 2570 } 2571 2572 kvo->kvo_vn_fileid = 0; 2573 kvo->kvo_vn_fsid = 0; 2574 kvo->kvo_vn_fsid_freebsd11 = 0; 2575 freepath = NULL; 2576 fullpath = ""; 2577 vp = NULL; 2578 kvo->kvo_type = vm_object_kvme_type(obj, want_path ? &vp : 2579 NULL); 2580 if (vp != NULL) { 2581 vref(vp); 2582 } else if ((obj->flags & OBJ_ANON) != 0) { 2583 MPASS(kvo->kvo_type == KVME_TYPE_SWAP); 2584 kvo->kvo_me = (uintptr_t)obj; 2585 /* tmpfs objs are reported as vnodes */ 2586 kvo->kvo_backing_obj = (uintptr_t)obj->backing_object; 2587 sp = swap_pager_swapped_pages(obj); 2588 kvo->kvo_swapped = sp > UINT32_MAX ? UINT32_MAX : sp; 2589 } 2590 VM_OBJECT_RUNLOCK(obj); 2591 if (vp != NULL) { 2592 vn_fullpath(vp, &fullpath, &freepath); 2593 vn_lock(vp, LK_SHARED | LK_RETRY); 2594 if (VOP_GETATTR(vp, &va, curthread->td_ucred) == 0) { 2595 kvo->kvo_vn_fileid = va.va_fileid; 2596 kvo->kvo_vn_fsid = va.va_fsid; 2597 kvo->kvo_vn_fsid_freebsd11 = va.va_fsid; 2598 /* truncate */ 2599 } 2600 vput(vp); 2601 } 2602 2603 strlcpy(kvo->kvo_path, fullpath, sizeof(kvo->kvo_path)); 2604 free(freepath, M_TEMP); 2605 2606 /* Pack record size down */ 2607 kvo->kvo_structsize = offsetof(struct kinfo_vmobject, kvo_path) 2608 + strlen(kvo->kvo_path) + 1; 2609 kvo->kvo_structsize = roundup(kvo->kvo_structsize, 2610 sizeof(uint64_t)); 2611 error = SYSCTL_OUT(req, kvo, kvo->kvo_structsize); 2612 maybe_yield(); 2613 mtx_lock(&vm_object_list_mtx); 2614 if (error) 2615 break; 2616 } 2617 mtx_unlock(&vm_object_list_mtx); 2618 free(kvo, M_TEMP); 2619 return (error); 2620 } 2621 2622 static int 2623 sysctl_vm_object_list(SYSCTL_HANDLER_ARGS) 2624 { 2625 return (vm_object_list_handler(req, false)); 2626 } 2627 2628 SYSCTL_PROC(_vm, OID_AUTO, objects, CTLTYPE_STRUCT | CTLFLAG_RW | CTLFLAG_SKIP | 2629 CTLFLAG_MPSAFE, NULL, 0, sysctl_vm_object_list, "S,kinfo_vmobject", 2630 "List of VM objects"); 2631 2632 static int 2633 sysctl_vm_object_list_swap(SYSCTL_HANDLER_ARGS) 2634 { 2635 return (vm_object_list_handler(req, true)); 2636 } 2637 2638 /* 2639 * This sysctl returns list of the anonymous or swap objects. Intent 2640 * is to provide stripped optimized list useful to analyze swap use. 2641 * Since technically non-swap (default) objects participate in the 2642 * shadow chains, and are converted to swap type as needed by swap 2643 * pager, we must report them. 2644 */ 2645 SYSCTL_PROC(_vm, OID_AUTO, swap_objects, 2646 CTLTYPE_STRUCT | CTLFLAG_RW | CTLFLAG_SKIP | CTLFLAG_MPSAFE, NULL, 0, 2647 sysctl_vm_object_list_swap, "S,kinfo_vmobject", 2648 "List of swap VM objects"); 2649 2650 #include "opt_ddb.h" 2651 #ifdef DDB 2652 #include <sys/kernel.h> 2653 2654 #include <sys/cons.h> 2655 2656 #include <ddb/ddb.h> 2657 2658 static int 2659 _vm_object_in_map(vm_map_t map, vm_object_t object, vm_map_entry_t entry) 2660 { 2661 vm_map_t tmpm; 2662 vm_map_entry_t tmpe; 2663 vm_object_t obj; 2664 2665 if (map == 0) 2666 return 0; 2667 2668 if (entry == 0) { 2669 VM_MAP_ENTRY_FOREACH(tmpe, map) { 2670 if (_vm_object_in_map(map, object, tmpe)) { 2671 return 1; 2672 } 2673 } 2674 } else if (entry->eflags & MAP_ENTRY_IS_SUB_MAP) { 2675 tmpm = entry->object.sub_map; 2676 VM_MAP_ENTRY_FOREACH(tmpe, tmpm) { 2677 if (_vm_object_in_map(tmpm, object, tmpe)) { 2678 return 1; 2679 } 2680 } 2681 } else if ((obj = entry->object.vm_object) != NULL) { 2682 for (; obj; obj = obj->backing_object) 2683 if (obj == object) { 2684 return 1; 2685 } 2686 } 2687 return 0; 2688 } 2689 2690 static int 2691 vm_object_in_map(vm_object_t object) 2692 { 2693 struct proc *p; 2694 2695 /* sx_slock(&allproc_lock); */ 2696 FOREACH_PROC_IN_SYSTEM(p) { 2697 if (!p->p_vmspace /* || (p->p_flag & (P_SYSTEM|P_WEXIT)) */) 2698 continue; 2699 if (_vm_object_in_map(&p->p_vmspace->vm_map, object, 0)) { 2700 /* sx_sunlock(&allproc_lock); */ 2701 return 1; 2702 } 2703 } 2704 /* sx_sunlock(&allproc_lock); */ 2705 if (_vm_object_in_map(kernel_map, object, 0)) 2706 return 1; 2707 return 0; 2708 } 2709 2710 DB_SHOW_COMMAND_FLAGS(vmochk, vm_object_check, DB_CMD_MEMSAFE) 2711 { 2712 vm_object_t object; 2713 2714 /* 2715 * make sure that internal objs are in a map somewhere 2716 * and none have zero ref counts. 2717 */ 2718 TAILQ_FOREACH(object, &vm_object_list, object_list) { 2719 if ((object->flags & OBJ_ANON) != 0) { 2720 if (object->ref_count == 0) { 2721 db_printf("vmochk: internal obj has zero ref count: %ld\n", 2722 (long)object->size); 2723 } 2724 if (!vm_object_in_map(object)) { 2725 db_printf( 2726 "vmochk: internal obj is not in a map: " 2727 "ref: %d, size: %lu: 0x%lx, backing_object: %p\n", 2728 object->ref_count, (u_long)object->size, 2729 (u_long)object->size, 2730 (void *)object->backing_object); 2731 } 2732 } 2733 if (db_pager_quit) 2734 return; 2735 } 2736 } 2737 2738 /* 2739 * vm_object_print: [ debug ] 2740 */ 2741 DB_SHOW_COMMAND(object, vm_object_print_static) 2742 { 2743 /* XXX convert args. */ 2744 vm_object_t object = (vm_object_t)addr; 2745 boolean_t full = have_addr; 2746 2747 vm_page_t p; 2748 2749 /* XXX count is an (unused) arg. Avoid shadowing it. */ 2750 #define count was_count 2751 2752 int count; 2753 2754 if (object == NULL) 2755 return; 2756 2757 db_iprintf( 2758 "Object %p: type=%d, size=0x%jx, res=%d, ref=%d, flags=0x%x ruid %d charge %jx\n", 2759 object, (int)object->type, (uintmax_t)object->size, 2760 object->resident_page_count, object->ref_count, object->flags, 2761 object->cred ? object->cred->cr_ruid : -1, (uintmax_t)object->charge); 2762 db_iprintf(" sref=%d, backing_object(%d)=(%p)+0x%jx\n", 2763 atomic_load_int(&object->shadow_count), 2764 object->backing_object ? object->backing_object->ref_count : 0, 2765 object->backing_object, (uintmax_t)object->backing_object_offset); 2766 2767 if (!full) 2768 return; 2769 2770 db_indent += 2; 2771 count = 0; 2772 TAILQ_FOREACH(p, &object->memq, listq) { 2773 if (count == 0) 2774 db_iprintf("memory:="); 2775 else if (count == 6) { 2776 db_printf("\n"); 2777 db_iprintf(" ..."); 2778 count = 0; 2779 } else 2780 db_printf(","); 2781 count++; 2782 2783 db_printf("(off=0x%jx,page=0x%jx)", 2784 (uintmax_t)p->pindex, (uintmax_t)VM_PAGE_TO_PHYS(p)); 2785 2786 if (db_pager_quit) 2787 break; 2788 } 2789 if (count != 0) 2790 db_printf("\n"); 2791 db_indent -= 2; 2792 } 2793 2794 /* XXX. */ 2795 #undef count 2796 2797 /* XXX need this non-static entry for calling from vm_map_print. */ 2798 void 2799 vm_object_print( 2800 /* db_expr_t */ long addr, 2801 boolean_t have_addr, 2802 /* db_expr_t */ long count, 2803 char *modif) 2804 { 2805 vm_object_print_static(addr, have_addr, count, modif); 2806 } 2807 2808 DB_SHOW_COMMAND_FLAGS(vmopag, vm_object_print_pages, DB_CMD_MEMSAFE) 2809 { 2810 vm_object_t object; 2811 vm_pindex_t fidx; 2812 vm_paddr_t pa; 2813 vm_page_t m, prev_m; 2814 int rcount; 2815 2816 TAILQ_FOREACH(object, &vm_object_list, object_list) { 2817 db_printf("new object: %p\n", (void *)object); 2818 if (db_pager_quit) 2819 return; 2820 2821 rcount = 0; 2822 fidx = 0; 2823 pa = -1; 2824 TAILQ_FOREACH(m, &object->memq, listq) { 2825 if ((prev_m = TAILQ_PREV(m, pglist, listq)) != NULL && 2826 prev_m->pindex + 1 != m->pindex) { 2827 if (rcount) { 2828 db_printf(" index(%ld)run(%d)pa(0x%lx)\n", 2829 (long)fidx, rcount, (long)pa); 2830 if (db_pager_quit) 2831 return; 2832 rcount = 0; 2833 } 2834 } 2835 if (rcount && 2836 (VM_PAGE_TO_PHYS(m) == pa + rcount * PAGE_SIZE)) { 2837 ++rcount; 2838 continue; 2839 } 2840 if (rcount) { 2841 db_printf(" index(%ld)run(%d)pa(0x%lx)\n", 2842 (long)fidx, rcount, (long)pa); 2843 if (db_pager_quit) 2844 return; 2845 } 2846 fidx = m->pindex; 2847 pa = VM_PAGE_TO_PHYS(m); 2848 rcount = 1; 2849 } 2850 if (rcount) { 2851 db_printf(" index(%ld)run(%d)pa(0x%lx)\n", 2852 (long)fidx, rcount, (long)pa); 2853 if (db_pager_quit) 2854 return; 2855 } 2856 } 2857 } 2858 #endif /* DDB */ 2859