1 /*- 2 * SPDX-License-Identifier: (BSD-3-Clause AND MIT-CMU) 3 * 4 * Copyright (c) 1991, 1993 5 * The Regents of the University of California. All rights reserved. 6 * 7 * This code is derived from software contributed to Berkeley by 8 * The Mach Operating System project at Carnegie-Mellon University. 9 * 10 * Redistribution and use in source and binary forms, with or without 11 * modification, are permitted provided that the following conditions 12 * are met: 13 * 1. Redistributions of source code must retain the above copyright 14 * notice, this list of conditions and the following disclaimer. 15 * 2. Redistributions in binary form must reproduce the above copyright 16 * notice, this list of conditions and the following disclaimer in the 17 * documentation and/or other materials provided with the distribution. 18 * 3. Neither the name of the University nor the names of its contributors 19 * may be used to endorse or promote products derived from this software 20 * without specific prior written permission. 21 * 22 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 23 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 24 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 25 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 26 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 27 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 28 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 29 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 30 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 31 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 32 * SUCH DAMAGE. 33 * 34 * from: @(#)vm_object.c 8.5 (Berkeley) 3/22/94 35 * 36 * 37 * Copyright (c) 1987, 1990 Carnegie-Mellon University. 38 * All rights reserved. 39 * 40 * Authors: Avadis Tevanian, Jr., Michael Wayne Young 41 * 42 * Permission to use, copy, modify and distribute this software and 43 * its documentation is hereby granted, provided that both the copyright 44 * notice and this permission notice appear in all copies of the 45 * software, derivative works or modified versions, and any portions 46 * thereof, and that both notices appear in supporting documentation. 47 * 48 * CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS" 49 * CONDITION. CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND 50 * FOR ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE. 51 * 52 * Carnegie Mellon requests users of this software to return to 53 * 54 * Software Distribution Coordinator or Software.Distribution@CS.CMU.EDU 55 * School of Computer Science 56 * Carnegie Mellon University 57 * Pittsburgh PA 15213-3890 58 * 59 * any improvements or extensions that they make and grant Carnegie the 60 * rights to redistribute these changes. 61 */ 62 63 /* 64 * Virtual memory object module. 65 */ 66 67 #include <sys/cdefs.h> 68 __FBSDID("$FreeBSD$"); 69 70 #include "opt_vm.h" 71 72 #include <sys/param.h> 73 #include <sys/systm.h> 74 #include <sys/blockcount.h> 75 #include <sys/cpuset.h> 76 #include <sys/limits.h> 77 #include <sys/lock.h> 78 #include <sys/mman.h> 79 #include <sys/mount.h> 80 #include <sys/kernel.h> 81 #include <sys/pctrie.h> 82 #include <sys/sysctl.h> 83 #include <sys/mutex.h> 84 #include <sys/proc.h> /* for curproc, pageproc */ 85 #include <sys/refcount.h> 86 #include <sys/socket.h> 87 #include <sys/resourcevar.h> 88 #include <sys/refcount.h> 89 #include <sys/rwlock.h> 90 #include <sys/user.h> 91 #include <sys/vnode.h> 92 #include <sys/vmmeter.h> 93 #include <sys/sx.h> 94 95 #include <vm/vm.h> 96 #include <vm/vm_param.h> 97 #include <vm/pmap.h> 98 #include <vm/vm_map.h> 99 #include <vm/vm_object.h> 100 #include <vm/vm_page.h> 101 #include <vm/vm_pageout.h> 102 #include <vm/vm_pager.h> 103 #include <vm/vm_phys.h> 104 #include <vm/vm_pagequeue.h> 105 #include <vm/swap_pager.h> 106 #include <vm/vm_kern.h> 107 #include <vm/vm_extern.h> 108 #include <vm/vm_radix.h> 109 #include <vm/vm_reserv.h> 110 #include <vm/uma.h> 111 112 static int old_msync; 113 SYSCTL_INT(_vm, OID_AUTO, old_msync, CTLFLAG_RW, &old_msync, 0, 114 "Use old (insecure) msync behavior"); 115 116 static int vm_object_page_collect_flush(vm_object_t object, vm_page_t p, 117 int pagerflags, int flags, boolean_t *allclean, 118 boolean_t *eio); 119 static boolean_t vm_object_page_remove_write(vm_page_t p, int flags, 120 boolean_t *allclean); 121 static void vm_object_backing_remove(vm_object_t object); 122 123 /* 124 * Virtual memory objects maintain the actual data 125 * associated with allocated virtual memory. A given 126 * page of memory exists within exactly one object. 127 * 128 * An object is only deallocated when all "references" 129 * are given up. Only one "reference" to a given 130 * region of an object should be writeable. 131 * 132 * Associated with each object is a list of all resident 133 * memory pages belonging to that object; this list is 134 * maintained by the "vm_page" module, and locked by the object's 135 * lock. 136 * 137 * Each object also records a "pager" routine which is 138 * used to retrieve (and store) pages to the proper backing 139 * storage. In addition, objects may be backed by other 140 * objects from which they were virtual-copied. 141 * 142 * The only items within the object structure which are 143 * modified after time of creation are: 144 * reference count locked by object's lock 145 * pager routine locked by object's lock 146 * 147 */ 148 149 struct object_q vm_object_list; 150 struct mtx vm_object_list_mtx; /* lock for object list and count */ 151 152 struct vm_object kernel_object_store; 153 154 static SYSCTL_NODE(_vm_stats, OID_AUTO, object, CTLFLAG_RD | CTLFLAG_MPSAFE, 0, 155 "VM object stats"); 156 157 static COUNTER_U64_DEFINE_EARLY(object_collapses); 158 SYSCTL_COUNTER_U64(_vm_stats_object, OID_AUTO, collapses, CTLFLAG_RD, 159 &object_collapses, 160 "VM object collapses"); 161 162 static COUNTER_U64_DEFINE_EARLY(object_bypasses); 163 SYSCTL_COUNTER_U64(_vm_stats_object, OID_AUTO, bypasses, CTLFLAG_RD, 164 &object_bypasses, 165 "VM object bypasses"); 166 167 static COUNTER_U64_DEFINE_EARLY(object_collapse_waits); 168 SYSCTL_COUNTER_U64(_vm_stats_object, OID_AUTO, collapse_waits, CTLFLAG_RD, 169 &object_collapse_waits, 170 "Number of sleeps for collapse"); 171 172 static uma_zone_t obj_zone; 173 174 static int vm_object_zinit(void *mem, int size, int flags); 175 176 #ifdef INVARIANTS 177 static void vm_object_zdtor(void *mem, int size, void *arg); 178 179 static void 180 vm_object_zdtor(void *mem, int size, void *arg) 181 { 182 vm_object_t object; 183 184 object = (vm_object_t)mem; 185 KASSERT(object->ref_count == 0, 186 ("object %p ref_count = %d", object, object->ref_count)); 187 KASSERT(TAILQ_EMPTY(&object->memq), 188 ("object %p has resident pages in its memq", object)); 189 KASSERT(vm_radix_is_empty(&object->rtree), 190 ("object %p has resident pages in its trie", object)); 191 #if VM_NRESERVLEVEL > 0 192 KASSERT(LIST_EMPTY(&object->rvq), 193 ("object %p has reservations", 194 object)); 195 #endif 196 KASSERT(!vm_object_busied(object), 197 ("object %p busy = %d", object, blockcount_read(&object->busy))); 198 KASSERT(object->resident_page_count == 0, 199 ("object %p resident_page_count = %d", 200 object, object->resident_page_count)); 201 KASSERT(atomic_load_int(&object->shadow_count) == 0, 202 ("object %p shadow_count = %d", 203 object, atomic_load_int(&object->shadow_count))); 204 KASSERT(object->type == OBJT_DEAD, 205 ("object %p has non-dead type %d", 206 object, object->type)); 207 } 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, "vm object", 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); 246 247 /* 248 * Ensure that swap_pager_swapoff() iteration over object_list 249 * sees up to date type and pctrie head if it observed 250 * non-dead object. 251 */ 252 atomic_thread_fence_rel(); 253 254 object->pg_color = 0; 255 object->size = size; 256 object->domain.dr_policy = NULL; 257 object->generation = 1; 258 object->cleangeneration = 1; 259 refcount_init(&object->ref_count, 1); 260 object->memattr = VM_MEMATTR_DEFAULT; 261 object->cred = NULL; 262 object->charge = 0; 263 object->handle = handle; 264 object->backing_object = NULL; 265 object->backing_object_offset = (vm_ooffset_t) 0; 266 #if VM_NRESERVLEVEL > 0 267 LIST_INIT(&object->rvq); 268 #endif 269 umtx_shm_object_init(object); 270 } 271 272 /* 273 * vm_object_init: 274 * 275 * Initialize the VM objects module. 276 */ 277 void 278 vm_object_init(void) 279 { 280 TAILQ_INIT(&vm_object_list); 281 mtx_init(&vm_object_list_mtx, "vm object_list", NULL, MTX_DEF); 282 283 rw_init(&kernel_object->lock, "kernel vm object"); 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_DEFAULT: 413 flags = OBJ_COLORED; 414 break; 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_DEFAULT, size, OBJ_ANON | OBJ_ONEMAPPING, 474 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_DEFAULT || 687 object->type == OBJT_SWAP, 688 ("shadowed tmpfs v_object 2 %p", object)); 689 vm_object_backing_remove(object); 690 } 691 692 KASSERT((object->flags & OBJ_DEAD) == 0, 693 ("vm_object_deallocate: Terminating dead object.")); 694 vm_object_set_flag(object, OBJ_DEAD); 695 vm_object_terminate(object); 696 object = temp; 697 } 698 } 699 700 /* 701 * vm_object_destroy removes the object from the global object list 702 * and frees the space for the object. 703 */ 704 void 705 vm_object_destroy(vm_object_t object) 706 { 707 708 /* 709 * Release the allocation charge. 710 */ 711 if (object->cred != NULL) { 712 swap_release_by_cred(object->charge, object->cred); 713 object->charge = 0; 714 crfree(object->cred); 715 object->cred = NULL; 716 } 717 718 /* 719 * Free the space for the object. 720 */ 721 uma_zfree(obj_zone, object); 722 } 723 724 static void 725 vm_object_sub_shadow(vm_object_t object) 726 { 727 KASSERT(object->shadow_count >= 1, 728 ("object %p sub_shadow count zero", object)); 729 atomic_subtract_int(&object->shadow_count, 1); 730 } 731 732 static void 733 vm_object_backing_remove_locked(vm_object_t object) 734 { 735 vm_object_t backing_object; 736 737 backing_object = object->backing_object; 738 VM_OBJECT_ASSERT_WLOCKED(object); 739 VM_OBJECT_ASSERT_WLOCKED(backing_object); 740 741 KASSERT((object->flags & OBJ_COLLAPSING) == 0, 742 ("vm_object_backing_remove: Removing collapsing object.")); 743 744 vm_object_sub_shadow(backing_object); 745 if ((object->flags & OBJ_SHADOWLIST) != 0) { 746 LIST_REMOVE(object, shadow_list); 747 vm_object_clear_flag(object, OBJ_SHADOWLIST); 748 } 749 object->backing_object = NULL; 750 } 751 752 static void 753 vm_object_backing_remove(vm_object_t object) 754 { 755 vm_object_t backing_object; 756 757 VM_OBJECT_ASSERT_WLOCKED(object); 758 759 backing_object = object->backing_object; 760 if ((object->flags & OBJ_SHADOWLIST) != 0) { 761 VM_OBJECT_WLOCK(backing_object); 762 vm_object_backing_remove_locked(object); 763 VM_OBJECT_WUNLOCK(backing_object); 764 } else { 765 object->backing_object = NULL; 766 vm_object_sub_shadow(backing_object); 767 } 768 } 769 770 static void 771 vm_object_backing_insert_locked(vm_object_t object, vm_object_t backing_object) 772 { 773 774 VM_OBJECT_ASSERT_WLOCKED(object); 775 776 atomic_add_int(&backing_object->shadow_count, 1); 777 if ((backing_object->flags & OBJ_ANON) != 0) { 778 VM_OBJECT_ASSERT_WLOCKED(backing_object); 779 LIST_INSERT_HEAD(&backing_object->shadow_head, object, 780 shadow_list); 781 vm_object_set_flag(object, OBJ_SHADOWLIST); 782 } 783 object->backing_object = backing_object; 784 } 785 786 static void 787 vm_object_backing_insert(vm_object_t object, vm_object_t backing_object) 788 { 789 790 VM_OBJECT_ASSERT_WLOCKED(object); 791 792 if ((backing_object->flags & OBJ_ANON) != 0) { 793 VM_OBJECT_WLOCK(backing_object); 794 vm_object_backing_insert_locked(object, backing_object); 795 VM_OBJECT_WUNLOCK(backing_object); 796 } else { 797 object->backing_object = backing_object; 798 atomic_add_int(&backing_object->shadow_count, 1); 799 } 800 } 801 802 /* 803 * Insert an object into a backing_object's shadow list with an additional 804 * reference to the backing_object added. 805 */ 806 static void 807 vm_object_backing_insert_ref(vm_object_t object, vm_object_t backing_object) 808 { 809 810 VM_OBJECT_ASSERT_WLOCKED(object); 811 812 if ((backing_object->flags & OBJ_ANON) != 0) { 813 VM_OBJECT_WLOCK(backing_object); 814 KASSERT((backing_object->flags & OBJ_DEAD) == 0, 815 ("shadowing dead anonymous object")); 816 vm_object_reference_locked(backing_object); 817 vm_object_backing_insert_locked(object, backing_object); 818 vm_object_clear_flag(backing_object, OBJ_ONEMAPPING); 819 VM_OBJECT_WUNLOCK(backing_object); 820 } else { 821 vm_object_reference(backing_object); 822 atomic_add_int(&backing_object->shadow_count, 1); 823 object->backing_object = backing_object; 824 } 825 } 826 827 /* 828 * Transfer a backing reference from backing_object to object. 829 */ 830 static void 831 vm_object_backing_transfer(vm_object_t object, vm_object_t backing_object) 832 { 833 vm_object_t new_backing_object; 834 835 /* 836 * Note that the reference to backing_object->backing_object 837 * moves from within backing_object to within object. 838 */ 839 vm_object_backing_remove_locked(object); 840 new_backing_object = backing_object->backing_object; 841 if (new_backing_object == NULL) 842 return; 843 if ((new_backing_object->flags & OBJ_ANON) != 0) { 844 VM_OBJECT_WLOCK(new_backing_object); 845 vm_object_backing_remove_locked(backing_object); 846 vm_object_backing_insert_locked(object, new_backing_object); 847 VM_OBJECT_WUNLOCK(new_backing_object); 848 } else { 849 /* 850 * shadow_count for new_backing_object is left 851 * unchanged, its reference provided by backing_object 852 * is replaced by object. 853 */ 854 object->backing_object = new_backing_object; 855 backing_object->backing_object = NULL; 856 } 857 } 858 859 /* 860 * Wait for a concurrent collapse to settle. 861 */ 862 static void 863 vm_object_collapse_wait(vm_object_t object) 864 { 865 866 VM_OBJECT_ASSERT_WLOCKED(object); 867 868 while ((object->flags & OBJ_COLLAPSING) != 0) { 869 vm_object_pip_wait(object, "vmcolwait"); 870 counter_u64_add(object_collapse_waits, 1); 871 } 872 } 873 874 /* 875 * Waits for a backing object to clear a pending collapse and returns 876 * it locked if it is an ANON object. 877 */ 878 static vm_object_t 879 vm_object_backing_collapse_wait(vm_object_t object) 880 { 881 vm_object_t backing_object; 882 883 VM_OBJECT_ASSERT_WLOCKED(object); 884 885 for (;;) { 886 backing_object = object->backing_object; 887 if (backing_object == NULL || 888 (backing_object->flags & OBJ_ANON) == 0) 889 return (NULL); 890 VM_OBJECT_WLOCK(backing_object); 891 if ((backing_object->flags & (OBJ_DEAD | OBJ_COLLAPSING)) == 0) 892 break; 893 VM_OBJECT_WUNLOCK(object); 894 vm_object_pip_sleep(backing_object, "vmbckwait"); 895 counter_u64_add(object_collapse_waits, 1); 896 VM_OBJECT_WLOCK(object); 897 } 898 return (backing_object); 899 } 900 901 /* 902 * vm_object_terminate_pages removes any remaining pageable pages 903 * from the object and resets the object to an empty state. 904 */ 905 static void 906 vm_object_terminate_pages(vm_object_t object) 907 { 908 vm_page_t p, p_next; 909 910 VM_OBJECT_ASSERT_WLOCKED(object); 911 912 /* 913 * Free any remaining pageable pages. This also removes them from the 914 * paging queues. However, don't free wired pages, just remove them 915 * from the object. Rather than incrementally removing each page from 916 * the object, the page and object are reset to any empty state. 917 */ 918 TAILQ_FOREACH_SAFE(p, &object->memq, listq, p_next) { 919 vm_page_assert_unbusied(p); 920 KASSERT(p->object == object && 921 (p->ref_count & VPRC_OBJREF) != 0, 922 ("vm_object_terminate_pages: page %p is inconsistent", p)); 923 924 p->object = NULL; 925 if (vm_page_drop(p, VPRC_OBJREF) == VPRC_OBJREF) { 926 VM_CNT_INC(v_pfree); 927 vm_page_free(p); 928 } 929 } 930 931 /* 932 * If the object contained any pages, then reset it to an empty state. 933 * None of the object's fields, including "resident_page_count", were 934 * modified by the preceding loop. 935 */ 936 if (object->resident_page_count != 0) { 937 vm_radix_reclaim_allnodes(&object->rtree); 938 TAILQ_INIT(&object->memq); 939 object->resident_page_count = 0; 940 if (object->type == OBJT_VNODE) 941 vdrop(object->handle); 942 } 943 } 944 945 /* 946 * vm_object_terminate actually destroys the specified object, freeing 947 * up all previously used resources. 948 * 949 * The object must be locked. 950 * This routine may block. 951 */ 952 void 953 vm_object_terminate(vm_object_t object) 954 { 955 956 VM_OBJECT_ASSERT_WLOCKED(object); 957 KASSERT((object->flags & OBJ_DEAD) != 0, 958 ("terminating non-dead obj %p", object)); 959 KASSERT((object->flags & OBJ_COLLAPSING) == 0, 960 ("terminating collapsing obj %p", object)); 961 KASSERT(object->backing_object == NULL, 962 ("terminating shadow obj %p", object)); 963 964 /* 965 * Wait for the pageout daemon and other current users to be 966 * done with the object. Note that new paging_in_progress 967 * users can come after this wait, but they must check 968 * OBJ_DEAD flag set (without unlocking the object), and avoid 969 * the object being terminated. 970 */ 971 vm_object_pip_wait(object, "objtrm"); 972 973 KASSERT(object->ref_count == 0, 974 ("vm_object_terminate: object with references, ref_count=%d", 975 object->ref_count)); 976 977 if ((object->flags & OBJ_PG_DTOR) == 0) 978 vm_object_terminate_pages(object); 979 980 #if VM_NRESERVLEVEL > 0 981 if (__predict_false(!LIST_EMPTY(&object->rvq))) 982 vm_reserv_break_all(object); 983 #endif 984 985 KASSERT(object->cred == NULL || object->type == OBJT_DEFAULT || 986 (object->flags & OBJ_SWAP) != 0, 987 ("%s: non-swap obj %p has cred", __func__, object)); 988 989 /* 990 * Let the pager know object is dead. 991 */ 992 vm_pager_deallocate(object); 993 VM_OBJECT_WUNLOCK(object); 994 995 vm_object_destroy(object); 996 } 997 998 /* 999 * Make the page read-only so that we can clear the object flags. However, if 1000 * this is a nosync mmap then the object is likely to stay dirty so do not 1001 * mess with the page and do not clear the object flags. Returns TRUE if the 1002 * page should be flushed, and FALSE otherwise. 1003 */ 1004 static boolean_t 1005 vm_object_page_remove_write(vm_page_t p, int flags, boolean_t *allclean) 1006 { 1007 1008 vm_page_assert_busied(p); 1009 1010 /* 1011 * If we have been asked to skip nosync pages and this is a 1012 * nosync page, skip it. Note that the object flags were not 1013 * cleared in this case so we do not have to set them. 1014 */ 1015 if ((flags & OBJPC_NOSYNC) != 0 && (p->a.flags & PGA_NOSYNC) != 0) { 1016 *allclean = FALSE; 1017 return (FALSE); 1018 } else { 1019 pmap_remove_write(p); 1020 return (p->dirty != 0); 1021 } 1022 } 1023 1024 /* 1025 * vm_object_page_clean 1026 * 1027 * Clean all dirty pages in the specified range of object. Leaves page 1028 * on whatever queue it is currently on. If NOSYNC is set then do not 1029 * write out pages with PGA_NOSYNC set (originally comes from MAP_NOSYNC), 1030 * leaving the object dirty. 1031 * 1032 * For swap objects backing tmpfs regular files, do not flush anything, 1033 * but remove write protection on the mapped pages to update mtime through 1034 * mmaped writes. 1035 * 1036 * When stuffing pages asynchronously, allow clustering. XXX we need a 1037 * synchronous clustering mode implementation. 1038 * 1039 * Odd semantics: if start == end, we clean everything. 1040 * 1041 * The object must be locked. 1042 * 1043 * Returns FALSE if some page from the range was not written, as 1044 * reported by the pager, and TRUE otherwise. 1045 */ 1046 boolean_t 1047 vm_object_page_clean(vm_object_t object, vm_ooffset_t start, vm_ooffset_t end, 1048 int flags) 1049 { 1050 vm_page_t np, p; 1051 vm_pindex_t pi, tend, tstart; 1052 int curgeneration, n, pagerflags; 1053 boolean_t eio, res, allclean; 1054 1055 VM_OBJECT_ASSERT_WLOCKED(object); 1056 1057 if (!vm_object_mightbedirty(object) || object->resident_page_count == 0) 1058 return (TRUE); 1059 1060 pagerflags = (flags & (OBJPC_SYNC | OBJPC_INVAL)) != 0 ? 1061 VM_PAGER_PUT_SYNC : VM_PAGER_CLUSTER_OK; 1062 pagerflags |= (flags & OBJPC_INVAL) != 0 ? VM_PAGER_PUT_INVAL : 0; 1063 1064 tstart = OFF_TO_IDX(start); 1065 tend = (end == 0) ? object->size : OFF_TO_IDX(end + PAGE_MASK); 1066 allclean = tstart == 0 && tend >= object->size; 1067 res = TRUE; 1068 1069 rescan: 1070 curgeneration = object->generation; 1071 1072 for (p = vm_page_find_least(object, tstart); p != NULL; p = np) { 1073 pi = p->pindex; 1074 if (pi >= tend) 1075 break; 1076 np = TAILQ_NEXT(p, listq); 1077 if (vm_page_none_valid(p)) 1078 continue; 1079 if (vm_page_busy_acquire(p, VM_ALLOC_WAITFAIL) == 0) { 1080 if (object->generation != curgeneration && 1081 (flags & OBJPC_SYNC) != 0) 1082 goto rescan; 1083 np = vm_page_find_least(object, pi); 1084 continue; 1085 } 1086 if (!vm_object_page_remove_write(p, flags, &allclean)) { 1087 vm_page_xunbusy(p); 1088 continue; 1089 } 1090 if (object->type == OBJT_VNODE) { 1091 n = vm_object_page_collect_flush(object, p, pagerflags, 1092 flags, &allclean, &eio); 1093 if (eio) { 1094 res = FALSE; 1095 allclean = FALSE; 1096 } 1097 if (object->generation != curgeneration && 1098 (flags & OBJPC_SYNC) != 0) 1099 goto rescan; 1100 1101 /* 1102 * If the VOP_PUTPAGES() did a truncated write, so 1103 * that even the first page of the run is not fully 1104 * written, vm_pageout_flush() returns 0 as the run 1105 * length. Since the condition that caused truncated 1106 * write may be permanent, e.g. exhausted free space, 1107 * accepting n == 0 would cause an infinite loop. 1108 * 1109 * Forwarding the iterator leaves the unwritten page 1110 * behind, but there is not much we can do there if 1111 * filesystem refuses to write it. 1112 */ 1113 if (n == 0) { 1114 n = 1; 1115 allclean = FALSE; 1116 } 1117 } else { 1118 n = 1; 1119 vm_page_xunbusy(p); 1120 } 1121 np = vm_page_find_least(object, pi + n); 1122 } 1123 #if 0 1124 VOP_FSYNC(vp, (pagerflags & VM_PAGER_PUT_SYNC) ? MNT_WAIT : 0); 1125 #endif 1126 1127 /* 1128 * Leave updating cleangeneration for tmpfs objects to tmpfs 1129 * scan. It needs to update mtime, which happens for other 1130 * filesystems during page writeouts. 1131 */ 1132 if (allclean && object->type == OBJT_VNODE) 1133 object->cleangeneration = curgeneration; 1134 return (res); 1135 } 1136 1137 static int 1138 vm_object_page_collect_flush(vm_object_t object, vm_page_t p, int pagerflags, 1139 int flags, boolean_t *allclean, boolean_t *eio) 1140 { 1141 vm_page_t ma[vm_pageout_page_count], p_first, tp; 1142 int count, i, mreq, runlen; 1143 1144 vm_page_lock_assert(p, MA_NOTOWNED); 1145 vm_page_assert_xbusied(p); 1146 VM_OBJECT_ASSERT_WLOCKED(object); 1147 1148 count = 1; 1149 mreq = 0; 1150 1151 for (tp = p; count < vm_pageout_page_count; count++) { 1152 tp = vm_page_next(tp); 1153 if (tp == NULL || vm_page_tryxbusy(tp) == 0) 1154 break; 1155 if (!vm_object_page_remove_write(tp, flags, allclean)) { 1156 vm_page_xunbusy(tp); 1157 break; 1158 } 1159 } 1160 1161 for (p_first = p; count < vm_pageout_page_count; count++) { 1162 tp = vm_page_prev(p_first); 1163 if (tp == NULL || vm_page_tryxbusy(tp) == 0) 1164 break; 1165 if (!vm_object_page_remove_write(tp, flags, allclean)) { 1166 vm_page_xunbusy(tp); 1167 break; 1168 } 1169 p_first = tp; 1170 mreq++; 1171 } 1172 1173 for (tp = p_first, i = 0; i < count; tp = TAILQ_NEXT(tp, listq), i++) 1174 ma[i] = tp; 1175 1176 vm_pageout_flush(ma, count, pagerflags, mreq, &runlen, eio); 1177 return (runlen); 1178 } 1179 1180 /* 1181 * Note that there is absolutely no sense in writing out 1182 * anonymous objects, so we track down the vnode object 1183 * to write out. 1184 * We invalidate (remove) all pages from the address space 1185 * for semantic correctness. 1186 * 1187 * If the backing object is a device object with unmanaged pages, then any 1188 * mappings to the specified range of pages must be removed before this 1189 * function is called. 1190 * 1191 * Note: certain anonymous maps, such as MAP_NOSYNC maps, 1192 * may start out with a NULL object. 1193 */ 1194 boolean_t 1195 vm_object_sync(vm_object_t object, vm_ooffset_t offset, vm_size_t size, 1196 boolean_t syncio, boolean_t invalidate) 1197 { 1198 vm_object_t backing_object; 1199 struct vnode *vp; 1200 struct mount *mp; 1201 int error, flags, fsync_after; 1202 boolean_t res; 1203 1204 if (object == NULL) 1205 return (TRUE); 1206 res = TRUE; 1207 error = 0; 1208 VM_OBJECT_WLOCK(object); 1209 while ((backing_object = object->backing_object) != NULL) { 1210 VM_OBJECT_WLOCK(backing_object); 1211 offset += object->backing_object_offset; 1212 VM_OBJECT_WUNLOCK(object); 1213 object = backing_object; 1214 if (object->size < OFF_TO_IDX(offset + size)) 1215 size = IDX_TO_OFF(object->size) - offset; 1216 } 1217 /* 1218 * Flush pages if writing is allowed, invalidate them 1219 * if invalidation requested. Pages undergoing I/O 1220 * will be ignored by vm_object_page_remove(). 1221 * 1222 * We cannot lock the vnode and then wait for paging 1223 * to complete without deadlocking against vm_fault. 1224 * Instead we simply call vm_object_page_remove() and 1225 * allow it to block internally on a page-by-page 1226 * basis when it encounters pages undergoing async 1227 * I/O. 1228 */ 1229 if (object->type == OBJT_VNODE && 1230 vm_object_mightbedirty(object) != 0 && 1231 ((vp = object->handle)->v_vflag & VV_NOSYNC) == 0) { 1232 VM_OBJECT_WUNLOCK(object); 1233 (void) vn_start_write(vp, &mp, V_WAIT); 1234 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY); 1235 if (syncio && !invalidate && offset == 0 && 1236 atop(size) == object->size) { 1237 /* 1238 * If syncing the whole mapping of the file, 1239 * it is faster to schedule all the writes in 1240 * async mode, also allowing the clustering, 1241 * and then wait for i/o to complete. 1242 */ 1243 flags = 0; 1244 fsync_after = TRUE; 1245 } else { 1246 flags = (syncio || invalidate) ? OBJPC_SYNC : 0; 1247 flags |= invalidate ? (OBJPC_SYNC | OBJPC_INVAL) : 0; 1248 fsync_after = FALSE; 1249 } 1250 VM_OBJECT_WLOCK(object); 1251 res = vm_object_page_clean(object, offset, offset + size, 1252 flags); 1253 VM_OBJECT_WUNLOCK(object); 1254 if (fsync_after) 1255 error = VOP_FSYNC(vp, MNT_WAIT, curthread); 1256 VOP_UNLOCK(vp); 1257 vn_finished_write(mp); 1258 if (error != 0) 1259 res = FALSE; 1260 VM_OBJECT_WLOCK(object); 1261 } 1262 if ((object->type == OBJT_VNODE || 1263 object->type == OBJT_DEVICE) && invalidate) { 1264 if (object->type == OBJT_DEVICE) 1265 /* 1266 * The option OBJPR_NOTMAPPED must be passed here 1267 * because vm_object_page_remove() cannot remove 1268 * unmanaged mappings. 1269 */ 1270 flags = OBJPR_NOTMAPPED; 1271 else if (old_msync) 1272 flags = 0; 1273 else 1274 flags = OBJPR_CLEANONLY; 1275 vm_object_page_remove(object, OFF_TO_IDX(offset), 1276 OFF_TO_IDX(offset + size + PAGE_MASK), flags); 1277 } 1278 VM_OBJECT_WUNLOCK(object); 1279 return (res); 1280 } 1281 1282 /* 1283 * Determine whether the given advice can be applied to the object. Advice is 1284 * not applied to unmanaged pages since they never belong to page queues, and 1285 * since MADV_FREE is destructive, it can apply only to anonymous pages that 1286 * have been mapped at most once. 1287 */ 1288 static bool 1289 vm_object_advice_applies(vm_object_t object, int advice) 1290 { 1291 1292 if ((object->flags & OBJ_UNMANAGED) != 0) 1293 return (false); 1294 if (advice != MADV_FREE) 1295 return (true); 1296 return ((object->flags & (OBJ_ONEMAPPING | OBJ_ANON)) == 1297 (OBJ_ONEMAPPING | OBJ_ANON)); 1298 } 1299 1300 static void 1301 vm_object_madvise_freespace(vm_object_t object, int advice, vm_pindex_t pindex, 1302 vm_size_t size) 1303 { 1304 1305 if (advice == MADV_FREE) 1306 vm_pager_freespace(object, pindex, size); 1307 } 1308 1309 /* 1310 * vm_object_madvise: 1311 * 1312 * Implements the madvise function at the object/page level. 1313 * 1314 * MADV_WILLNEED (any object) 1315 * 1316 * Activate the specified pages if they are resident. 1317 * 1318 * MADV_DONTNEED (any object) 1319 * 1320 * Deactivate the specified pages if they are resident. 1321 * 1322 * MADV_FREE (OBJT_DEFAULT/OBJT_SWAP objects, 1323 * OBJ_ONEMAPPING only) 1324 * 1325 * Deactivate and clean the specified pages if they are 1326 * resident. This permits the process to reuse the pages 1327 * without faulting or the kernel to reclaim the pages 1328 * without I/O. 1329 */ 1330 void 1331 vm_object_madvise(vm_object_t object, vm_pindex_t pindex, vm_pindex_t end, 1332 int advice) 1333 { 1334 vm_pindex_t tpindex; 1335 vm_object_t backing_object, tobject; 1336 vm_page_t m, tm; 1337 1338 if (object == NULL) 1339 return; 1340 1341 relookup: 1342 VM_OBJECT_WLOCK(object); 1343 if (!vm_object_advice_applies(object, advice)) { 1344 VM_OBJECT_WUNLOCK(object); 1345 return; 1346 } 1347 for (m = vm_page_find_least(object, pindex); pindex < end; pindex++) { 1348 tobject = object; 1349 1350 /* 1351 * If the next page isn't resident in the top-level object, we 1352 * need to search the shadow chain. When applying MADV_FREE, we 1353 * take care to release any swap space used to store 1354 * non-resident pages. 1355 */ 1356 if (m == NULL || pindex < m->pindex) { 1357 /* 1358 * Optimize a common case: if the top-level object has 1359 * no backing object, we can skip over the non-resident 1360 * range in constant time. 1361 */ 1362 if (object->backing_object == NULL) { 1363 tpindex = (m != NULL && m->pindex < end) ? 1364 m->pindex : end; 1365 vm_object_madvise_freespace(object, advice, 1366 pindex, tpindex - pindex); 1367 if ((pindex = tpindex) == end) 1368 break; 1369 goto next_page; 1370 } 1371 1372 tpindex = pindex; 1373 do { 1374 vm_object_madvise_freespace(tobject, advice, 1375 tpindex, 1); 1376 /* 1377 * Prepare to search the next object in the 1378 * chain. 1379 */ 1380 backing_object = tobject->backing_object; 1381 if (backing_object == NULL) 1382 goto next_pindex; 1383 VM_OBJECT_WLOCK(backing_object); 1384 tpindex += 1385 OFF_TO_IDX(tobject->backing_object_offset); 1386 if (tobject != object) 1387 VM_OBJECT_WUNLOCK(tobject); 1388 tobject = backing_object; 1389 if (!vm_object_advice_applies(tobject, advice)) 1390 goto next_pindex; 1391 } while ((tm = vm_page_lookup(tobject, tpindex)) == 1392 NULL); 1393 } else { 1394 next_page: 1395 tm = m; 1396 m = TAILQ_NEXT(m, listq); 1397 } 1398 1399 /* 1400 * If the page is not in a normal state, skip it. The page 1401 * can not be invalidated while the object lock is held. 1402 */ 1403 if (!vm_page_all_valid(tm) || vm_page_wired(tm)) 1404 goto next_pindex; 1405 KASSERT((tm->flags & PG_FICTITIOUS) == 0, 1406 ("vm_object_madvise: page %p is fictitious", tm)); 1407 KASSERT((tm->oflags & VPO_UNMANAGED) == 0, 1408 ("vm_object_madvise: page %p is not managed", tm)); 1409 if (vm_page_tryxbusy(tm) == 0) { 1410 if (object != tobject) 1411 VM_OBJECT_WUNLOCK(object); 1412 if (advice == MADV_WILLNEED) { 1413 /* 1414 * Reference the page before unlocking and 1415 * sleeping so that the page daemon is less 1416 * likely to reclaim it. 1417 */ 1418 vm_page_aflag_set(tm, PGA_REFERENCED); 1419 } 1420 if (!vm_page_busy_sleep(tm, "madvpo", 0)) 1421 VM_OBJECT_WUNLOCK(tobject); 1422 goto relookup; 1423 } 1424 vm_page_advise(tm, advice); 1425 vm_page_xunbusy(tm); 1426 vm_object_madvise_freespace(tobject, advice, tm->pindex, 1); 1427 next_pindex: 1428 if (tobject != object) 1429 VM_OBJECT_WUNLOCK(tobject); 1430 } 1431 VM_OBJECT_WUNLOCK(object); 1432 } 1433 1434 /* 1435 * vm_object_shadow: 1436 * 1437 * Create a new object which is backed by the 1438 * specified existing object range. The source 1439 * object reference is deallocated. 1440 * 1441 * The new object and offset into that object 1442 * are returned in the source parameters. 1443 */ 1444 void 1445 vm_object_shadow(vm_object_t *object, vm_ooffset_t *offset, vm_size_t length, 1446 struct ucred *cred, bool shared) 1447 { 1448 vm_object_t source; 1449 vm_object_t result; 1450 1451 source = *object; 1452 1453 /* 1454 * Don't create the new object if the old object isn't shared. 1455 * 1456 * If we hold the only reference we can guarantee that it won't 1457 * increase while we have the map locked. Otherwise the race is 1458 * harmless and we will end up with an extra shadow object that 1459 * will be collapsed later. 1460 */ 1461 if (source != NULL && source->ref_count == 1 && 1462 (source->flags & OBJ_ANON) != 0) 1463 return; 1464 1465 /* 1466 * Allocate a new object with the given length. 1467 */ 1468 result = vm_object_allocate_anon(atop(length), source, cred, length); 1469 1470 /* 1471 * Store the offset into the source object, and fix up the offset into 1472 * the new object. 1473 */ 1474 result->backing_object_offset = *offset; 1475 1476 if (shared || source != NULL) { 1477 VM_OBJECT_WLOCK(result); 1478 1479 /* 1480 * The new object shadows the source object, adding a 1481 * reference to it. Our caller changes his reference 1482 * to point to the new object, removing a reference to 1483 * the source object. Net result: no change of 1484 * reference count, unless the caller needs to add one 1485 * more reference due to forking a shared map entry. 1486 */ 1487 if (shared) { 1488 vm_object_reference_locked(result); 1489 vm_object_clear_flag(result, OBJ_ONEMAPPING); 1490 } 1491 1492 /* 1493 * Try to optimize the result object's page color when 1494 * shadowing in order to maintain page coloring 1495 * consistency in the combined shadowed object. 1496 */ 1497 if (source != NULL) { 1498 vm_object_backing_insert(result, source); 1499 result->domain = source->domain; 1500 #if VM_NRESERVLEVEL > 0 1501 vm_object_set_flag(result, 1502 (source->flags & OBJ_COLORED)); 1503 result->pg_color = (source->pg_color + 1504 OFF_TO_IDX(*offset)) & ((1 << (VM_NFREEORDER - 1505 1)) - 1); 1506 #endif 1507 } 1508 VM_OBJECT_WUNLOCK(result); 1509 } 1510 1511 /* 1512 * Return the new things 1513 */ 1514 *offset = 0; 1515 *object = result; 1516 } 1517 1518 /* 1519 * vm_object_split: 1520 * 1521 * Split the pages in a map entry into a new object. This affords 1522 * easier removal of unused pages, and keeps object inheritance from 1523 * being a negative impact on memory usage. 1524 */ 1525 void 1526 vm_object_split(vm_map_entry_t entry) 1527 { 1528 vm_page_t m, m_busy, m_next; 1529 vm_object_t orig_object, new_object, backing_object; 1530 vm_pindex_t idx, offidxstart; 1531 vm_size_t size; 1532 1533 orig_object = entry->object.vm_object; 1534 KASSERT((orig_object->flags & OBJ_ONEMAPPING) != 0, 1535 ("vm_object_split: Splitting object with multiple mappings.")); 1536 if ((orig_object->flags & OBJ_ANON) == 0) 1537 return; 1538 if (orig_object->ref_count <= 1) 1539 return; 1540 VM_OBJECT_WUNLOCK(orig_object); 1541 1542 offidxstart = OFF_TO_IDX(entry->offset); 1543 size = atop(entry->end - entry->start); 1544 1545 /* 1546 * If swap_pager_copy() is later called, it will convert new_object 1547 * into a swap object. 1548 */ 1549 new_object = vm_object_allocate_anon(size, orig_object, 1550 orig_object->cred, ptoa(size)); 1551 1552 /* 1553 * We must wait for the orig_object to complete any in-progress 1554 * collapse so that the swap blocks are stable below. The 1555 * additional reference on backing_object by new object will 1556 * prevent further collapse operations until split completes. 1557 */ 1558 VM_OBJECT_WLOCK(orig_object); 1559 vm_object_collapse_wait(orig_object); 1560 1561 /* 1562 * At this point, the new object is still private, so the order in 1563 * which the original and new objects are locked does not matter. 1564 */ 1565 VM_OBJECT_WLOCK(new_object); 1566 new_object->domain = orig_object->domain; 1567 backing_object = orig_object->backing_object; 1568 if (backing_object != NULL) { 1569 vm_object_backing_insert_ref(new_object, backing_object); 1570 new_object->backing_object_offset = 1571 orig_object->backing_object_offset + entry->offset; 1572 } 1573 if (orig_object->cred != NULL) { 1574 crhold(orig_object->cred); 1575 KASSERT(orig_object->charge >= ptoa(size), 1576 ("orig_object->charge < 0")); 1577 orig_object->charge -= ptoa(size); 1578 } 1579 1580 /* 1581 * Mark the split operation so that swap_pager_getpages() knows 1582 * that the object is in transition. 1583 */ 1584 vm_object_set_flag(orig_object, OBJ_SPLIT); 1585 m_busy = NULL; 1586 #ifdef INVARIANTS 1587 idx = 0; 1588 #endif 1589 retry: 1590 m = vm_page_find_least(orig_object, offidxstart); 1591 KASSERT(m == NULL || idx <= m->pindex - offidxstart, 1592 ("%s: object %p was repopulated", __func__, orig_object)); 1593 for (; m != NULL && (idx = m->pindex - offidxstart) < size; 1594 m = m_next) { 1595 m_next = TAILQ_NEXT(m, listq); 1596 1597 /* 1598 * We must wait for pending I/O to complete before we can 1599 * rename the page. 1600 * 1601 * We do not have to VM_PROT_NONE the page as mappings should 1602 * not be changed by this operation. 1603 */ 1604 if (vm_page_tryxbusy(m) == 0) { 1605 VM_OBJECT_WUNLOCK(new_object); 1606 if (vm_page_busy_sleep(m, "spltwt", 0)) 1607 VM_OBJECT_WLOCK(orig_object); 1608 VM_OBJECT_WLOCK(new_object); 1609 goto retry; 1610 } 1611 1612 /* 1613 * The page was left invalid. Likely placed there by 1614 * an incomplete fault. Just remove and ignore. 1615 */ 1616 if (vm_page_none_valid(m)) { 1617 if (vm_page_remove(m)) 1618 vm_page_free(m); 1619 continue; 1620 } 1621 1622 /* vm_page_rename() will dirty the page. */ 1623 if (vm_page_rename(m, new_object, idx)) { 1624 vm_page_xunbusy(m); 1625 VM_OBJECT_WUNLOCK(new_object); 1626 VM_OBJECT_WUNLOCK(orig_object); 1627 vm_radix_wait(); 1628 VM_OBJECT_WLOCK(orig_object); 1629 VM_OBJECT_WLOCK(new_object); 1630 goto retry; 1631 } 1632 1633 #if VM_NRESERVLEVEL > 0 1634 /* 1635 * If some of the reservation's allocated pages remain with 1636 * the original object, then transferring the reservation to 1637 * the new object is neither particularly beneficial nor 1638 * particularly harmful as compared to leaving the reservation 1639 * with the original object. If, however, all of the 1640 * reservation's allocated pages are transferred to the new 1641 * object, then transferring the reservation is typically 1642 * beneficial. Determining which of these two cases applies 1643 * would be more costly than unconditionally renaming the 1644 * reservation. 1645 */ 1646 vm_reserv_rename(m, new_object, orig_object, offidxstart); 1647 #endif 1648 1649 /* 1650 * orig_object's type may change while sleeping, so keep track 1651 * of the beginning of the busied range. 1652 */ 1653 if (orig_object->type != OBJT_SWAP) 1654 vm_page_xunbusy(m); 1655 else if (m_busy == NULL) 1656 m_busy = m; 1657 } 1658 if ((orig_object->flags & OBJ_SWAP) != 0) { 1659 /* 1660 * swap_pager_copy() can sleep, in which case the orig_object's 1661 * and new_object's locks are released and reacquired. 1662 */ 1663 swap_pager_copy(orig_object, new_object, offidxstart, 0); 1664 if (m_busy != NULL) 1665 TAILQ_FOREACH_FROM(m_busy, &new_object->memq, listq) 1666 vm_page_xunbusy(m_busy); 1667 } 1668 vm_object_clear_flag(orig_object, OBJ_SPLIT); 1669 VM_OBJECT_WUNLOCK(orig_object); 1670 VM_OBJECT_WUNLOCK(new_object); 1671 entry->object.vm_object = new_object; 1672 entry->offset = 0LL; 1673 vm_object_deallocate(orig_object); 1674 VM_OBJECT_WLOCK(new_object); 1675 } 1676 1677 static vm_page_t 1678 vm_object_collapse_scan_wait(vm_object_t object, vm_page_t p) 1679 { 1680 vm_object_t backing_object; 1681 1682 VM_OBJECT_ASSERT_WLOCKED(object); 1683 backing_object = object->backing_object; 1684 VM_OBJECT_ASSERT_WLOCKED(backing_object); 1685 1686 KASSERT(p == NULL || p->object == object || p->object == backing_object, 1687 ("invalid ownership %p %p %p", p, object, backing_object)); 1688 /* The page is only NULL when rename fails. */ 1689 if (p == NULL) { 1690 VM_OBJECT_WUNLOCK(object); 1691 VM_OBJECT_WUNLOCK(backing_object); 1692 vm_radix_wait(); 1693 VM_OBJECT_WLOCK(object); 1694 } else if (p->object == object) { 1695 VM_OBJECT_WUNLOCK(backing_object); 1696 if (vm_page_busy_sleep(p, "vmocol", 0)) 1697 VM_OBJECT_WLOCK(object); 1698 } else { 1699 VM_OBJECT_WUNLOCK(object); 1700 if (!vm_page_busy_sleep(p, "vmocol", 0)) 1701 VM_OBJECT_WUNLOCK(backing_object); 1702 VM_OBJECT_WLOCK(object); 1703 } 1704 VM_OBJECT_WLOCK(backing_object); 1705 return (TAILQ_FIRST(&backing_object->memq)); 1706 } 1707 1708 static bool 1709 vm_object_scan_all_shadowed(vm_object_t object) 1710 { 1711 vm_object_t backing_object; 1712 vm_page_t p, pp; 1713 vm_pindex_t backing_offset_index, new_pindex, pi, ps; 1714 1715 VM_OBJECT_ASSERT_WLOCKED(object); 1716 VM_OBJECT_ASSERT_WLOCKED(object->backing_object); 1717 1718 backing_object = object->backing_object; 1719 1720 if ((backing_object->flags & OBJ_ANON) == 0) 1721 return (false); 1722 1723 pi = backing_offset_index = OFF_TO_IDX(object->backing_object_offset); 1724 p = vm_page_find_least(backing_object, pi); 1725 ps = swap_pager_find_least(backing_object, pi); 1726 1727 /* 1728 * Only check pages inside the parent object's range and 1729 * inside the parent object's mapping of the backing object. 1730 */ 1731 for (;; pi++) { 1732 if (p != NULL && p->pindex < pi) 1733 p = TAILQ_NEXT(p, listq); 1734 if (ps < pi) 1735 ps = swap_pager_find_least(backing_object, pi); 1736 if (p == NULL && ps >= backing_object->size) 1737 break; 1738 else if (p == NULL) 1739 pi = ps; 1740 else 1741 pi = MIN(p->pindex, ps); 1742 1743 new_pindex = pi - backing_offset_index; 1744 if (new_pindex >= object->size) 1745 break; 1746 1747 if (p != NULL) { 1748 /* 1749 * If the backing object page is busy a 1750 * grandparent or older page may still be 1751 * undergoing CoW. It is not safe to collapse 1752 * the backing object until it is quiesced. 1753 */ 1754 if (vm_page_tryxbusy(p) == 0) 1755 return (false); 1756 1757 /* 1758 * We raced with the fault handler that left 1759 * newly allocated invalid page on the object 1760 * queue and retried. 1761 */ 1762 if (!vm_page_all_valid(p)) 1763 goto unbusy_ret; 1764 } 1765 1766 /* 1767 * See if the parent has the page or if the parent's object 1768 * pager has the page. If the parent has the page but the page 1769 * is not valid, the parent's object pager must have the page. 1770 * 1771 * If this fails, the parent does not completely shadow the 1772 * object and we might as well give up now. 1773 */ 1774 pp = vm_page_lookup(object, new_pindex); 1775 1776 /* 1777 * The valid check here is stable due to object lock 1778 * being required to clear valid and initiate paging. 1779 * Busy of p disallows fault handler to validate pp. 1780 */ 1781 if ((pp == NULL || vm_page_none_valid(pp)) && 1782 !vm_pager_has_page(object, new_pindex, NULL, NULL)) 1783 goto unbusy_ret; 1784 if (p != NULL) 1785 vm_page_xunbusy(p); 1786 } 1787 return (true); 1788 1789 unbusy_ret: 1790 if (p != NULL) 1791 vm_page_xunbusy(p); 1792 return (false); 1793 } 1794 1795 static void 1796 vm_object_collapse_scan(vm_object_t object) 1797 { 1798 vm_object_t backing_object; 1799 vm_page_t next, p, pp; 1800 vm_pindex_t backing_offset_index, new_pindex; 1801 1802 VM_OBJECT_ASSERT_WLOCKED(object); 1803 VM_OBJECT_ASSERT_WLOCKED(object->backing_object); 1804 1805 backing_object = object->backing_object; 1806 backing_offset_index = OFF_TO_IDX(object->backing_object_offset); 1807 1808 /* 1809 * Our scan 1810 */ 1811 for (p = TAILQ_FIRST(&backing_object->memq); p != NULL; p = next) { 1812 next = TAILQ_NEXT(p, listq); 1813 new_pindex = p->pindex - backing_offset_index; 1814 1815 /* 1816 * Check for busy page 1817 */ 1818 if (vm_page_tryxbusy(p) == 0) { 1819 next = vm_object_collapse_scan_wait(object, p); 1820 continue; 1821 } 1822 1823 KASSERT(object->backing_object == backing_object, 1824 ("vm_object_collapse_scan: backing object mismatch %p != %p", 1825 object->backing_object, backing_object)); 1826 KASSERT(p->object == backing_object, 1827 ("vm_object_collapse_scan: object mismatch %p != %p", 1828 p->object, backing_object)); 1829 1830 if (p->pindex < backing_offset_index || 1831 new_pindex >= object->size) { 1832 vm_pager_freespace(backing_object, p->pindex, 1); 1833 1834 KASSERT(!pmap_page_is_mapped(p), 1835 ("freeing mapped page %p", p)); 1836 if (vm_page_remove(p)) 1837 vm_page_free(p); 1838 continue; 1839 } 1840 1841 if (!vm_page_all_valid(p)) { 1842 KASSERT(!pmap_page_is_mapped(p), 1843 ("freeing mapped page %p", p)); 1844 if (vm_page_remove(p)) 1845 vm_page_free(p); 1846 continue; 1847 } 1848 1849 pp = vm_page_lookup(object, new_pindex); 1850 if (pp != NULL && vm_page_tryxbusy(pp) == 0) { 1851 vm_page_xunbusy(p); 1852 /* 1853 * The page in the parent is busy and possibly not 1854 * (yet) valid. Until its state is finalized by the 1855 * busy bit owner, we can't tell whether it shadows the 1856 * original page. 1857 */ 1858 next = vm_object_collapse_scan_wait(object, pp); 1859 continue; 1860 } 1861 1862 if (pp != NULL && vm_page_none_valid(pp)) { 1863 /* 1864 * The page was invalid in the parent. Likely placed 1865 * there by an incomplete fault. Just remove and 1866 * ignore. p can replace it. 1867 */ 1868 if (vm_page_remove(pp)) 1869 vm_page_free(pp); 1870 pp = NULL; 1871 } 1872 1873 if (pp != NULL || vm_pager_has_page(object, new_pindex, NULL, 1874 NULL)) { 1875 /* 1876 * The page already exists in the parent OR swap exists 1877 * for this location in the parent. Leave the parent's 1878 * page alone. Destroy the original page from the 1879 * backing object. 1880 */ 1881 vm_pager_freespace(backing_object, p->pindex, 1); 1882 KASSERT(!pmap_page_is_mapped(p), 1883 ("freeing mapped page %p", p)); 1884 if (vm_page_remove(p)) 1885 vm_page_free(p); 1886 if (pp != NULL) 1887 vm_page_xunbusy(pp); 1888 continue; 1889 } 1890 1891 /* 1892 * Page does not exist in parent, rename the page from the 1893 * backing object to the main object. 1894 * 1895 * If the page was mapped to a process, it can remain mapped 1896 * through the rename. vm_page_rename() will dirty the page. 1897 */ 1898 if (vm_page_rename(p, object, new_pindex)) { 1899 vm_page_xunbusy(p); 1900 next = vm_object_collapse_scan_wait(object, NULL); 1901 continue; 1902 } 1903 1904 /* Use the old pindex to free the right page. */ 1905 vm_pager_freespace(backing_object, new_pindex + 1906 backing_offset_index, 1); 1907 1908 #if VM_NRESERVLEVEL > 0 1909 /* 1910 * Rename the reservation. 1911 */ 1912 vm_reserv_rename(p, object, backing_object, 1913 backing_offset_index); 1914 #endif 1915 vm_page_xunbusy(p); 1916 } 1917 return; 1918 } 1919 1920 /* 1921 * vm_object_collapse: 1922 * 1923 * Collapse an object with the object backing it. 1924 * Pages in the backing object are moved into the 1925 * parent, and the backing object is deallocated. 1926 */ 1927 void 1928 vm_object_collapse(vm_object_t object) 1929 { 1930 vm_object_t backing_object, new_backing_object; 1931 1932 VM_OBJECT_ASSERT_WLOCKED(object); 1933 1934 while (TRUE) { 1935 KASSERT((object->flags & (OBJ_DEAD | OBJ_ANON)) == OBJ_ANON, 1936 ("collapsing invalid object")); 1937 1938 /* 1939 * Wait for the backing_object to finish any pending 1940 * collapse so that the caller sees the shortest possible 1941 * shadow chain. 1942 */ 1943 backing_object = vm_object_backing_collapse_wait(object); 1944 if (backing_object == NULL) 1945 return; 1946 1947 KASSERT(object->ref_count > 0 && 1948 object->ref_count > atomic_load_int(&object->shadow_count), 1949 ("collapse with invalid ref %d or shadow %d count.", 1950 object->ref_count, atomic_load_int(&object->shadow_count))); 1951 KASSERT((backing_object->flags & 1952 (OBJ_COLLAPSING | OBJ_DEAD)) == 0, 1953 ("vm_object_collapse: Backing object already collapsing.")); 1954 KASSERT((object->flags & (OBJ_COLLAPSING | OBJ_DEAD)) == 0, 1955 ("vm_object_collapse: object is already collapsing.")); 1956 1957 /* 1958 * We know that we can either collapse the backing object if 1959 * the parent is the only reference to it, or (perhaps) have 1960 * the parent bypass the object if the parent happens to shadow 1961 * all the resident pages in the entire backing object. 1962 */ 1963 if (backing_object->ref_count == 1) { 1964 KASSERT(atomic_load_int(&backing_object->shadow_count) 1965 == 1, 1966 ("vm_object_collapse: shadow_count: %d", 1967 atomic_load_int(&backing_object->shadow_count))); 1968 vm_object_pip_add(object, 1); 1969 vm_object_set_flag(object, OBJ_COLLAPSING); 1970 vm_object_pip_add(backing_object, 1); 1971 vm_object_set_flag(backing_object, OBJ_DEAD); 1972 1973 /* 1974 * If there is exactly one reference to the backing 1975 * object, we can collapse it into the parent. 1976 */ 1977 vm_object_collapse_scan(object); 1978 1979 #if VM_NRESERVLEVEL > 0 1980 /* 1981 * Break any reservations from backing_object. 1982 */ 1983 if (__predict_false(!LIST_EMPTY(&backing_object->rvq))) 1984 vm_reserv_break_all(backing_object); 1985 #endif 1986 1987 /* 1988 * Move the pager from backing_object to object. 1989 */ 1990 if ((backing_object->flags & OBJ_SWAP) != 0) { 1991 /* 1992 * swap_pager_copy() can sleep, in which case 1993 * the backing_object's and object's locks are 1994 * released and reacquired. 1995 * Since swap_pager_copy() is being asked to 1996 * destroy backing_object, it will change the 1997 * type to OBJT_DEFAULT. 1998 */ 1999 swap_pager_copy( 2000 backing_object, 2001 object, 2002 OFF_TO_IDX(object->backing_object_offset), TRUE); 2003 } 2004 2005 /* 2006 * Object now shadows whatever backing_object did. 2007 */ 2008 vm_object_clear_flag(object, OBJ_COLLAPSING); 2009 vm_object_backing_transfer(object, backing_object); 2010 object->backing_object_offset += 2011 backing_object->backing_object_offset; 2012 VM_OBJECT_WUNLOCK(object); 2013 vm_object_pip_wakeup(object); 2014 2015 /* 2016 * Discard backing_object. 2017 * 2018 * Since the backing object has no pages, no pager left, 2019 * and no object references within it, all that is 2020 * necessary is to dispose of it. 2021 */ 2022 KASSERT(backing_object->ref_count == 1, ( 2023 "backing_object %p was somehow re-referenced during collapse!", 2024 backing_object)); 2025 vm_object_pip_wakeup(backing_object); 2026 (void)refcount_release(&backing_object->ref_count); 2027 vm_object_terminate(backing_object); 2028 counter_u64_add(object_collapses, 1); 2029 VM_OBJECT_WLOCK(object); 2030 } else { 2031 /* 2032 * If we do not entirely shadow the backing object, 2033 * there is nothing we can do so we give up. 2034 * 2035 * The object lock and backing_object lock must not 2036 * be dropped during this sequence. 2037 */ 2038 if (!vm_object_scan_all_shadowed(object)) { 2039 VM_OBJECT_WUNLOCK(backing_object); 2040 break; 2041 } 2042 2043 /* 2044 * Make the parent shadow the next object in the 2045 * chain. Deallocating backing_object will not remove 2046 * it, since its reference count is at least 2. 2047 */ 2048 vm_object_backing_remove_locked(object); 2049 new_backing_object = backing_object->backing_object; 2050 if (new_backing_object != NULL) { 2051 vm_object_backing_insert_ref(object, 2052 new_backing_object); 2053 object->backing_object_offset += 2054 backing_object->backing_object_offset; 2055 } 2056 2057 /* 2058 * Drop the reference count on backing_object. Since 2059 * its ref_count was at least 2, it will not vanish. 2060 */ 2061 (void)refcount_release(&backing_object->ref_count); 2062 KASSERT(backing_object->ref_count >= 1, ( 2063 "backing_object %p was somehow dereferenced during collapse!", 2064 backing_object)); 2065 VM_OBJECT_WUNLOCK(backing_object); 2066 counter_u64_add(object_bypasses, 1); 2067 } 2068 2069 /* 2070 * Try again with this object's new backing object. 2071 */ 2072 } 2073 } 2074 2075 /* 2076 * vm_object_page_remove: 2077 * 2078 * For the given object, either frees or invalidates each of the 2079 * specified pages. In general, a page is freed. However, if a page is 2080 * wired for any reason other than the existence of a managed, wired 2081 * mapping, then it may be invalidated but not removed from the object. 2082 * Pages are specified by the given range ["start", "end") and the option 2083 * OBJPR_CLEANONLY. As a special case, if "end" is zero, then the range 2084 * extends from "start" to the end of the object. If the option 2085 * OBJPR_CLEANONLY is specified, then only the non-dirty pages within the 2086 * specified range are affected. If the option OBJPR_NOTMAPPED is 2087 * specified, then the pages within the specified range must have no 2088 * mappings. Otherwise, if this option is not specified, any mappings to 2089 * the specified pages are removed before the pages are freed or 2090 * invalidated. 2091 * 2092 * In general, this operation should only be performed on objects that 2093 * contain managed pages. There are, however, two exceptions. First, it 2094 * is performed on the kernel and kmem objects by vm_map_entry_delete(). 2095 * Second, it is used by msync(..., MS_INVALIDATE) to invalidate device- 2096 * backed pages. In both of these cases, the option OBJPR_CLEANONLY must 2097 * not be specified and the option OBJPR_NOTMAPPED must be specified. 2098 * 2099 * The object must be locked. 2100 */ 2101 void 2102 vm_object_page_remove(vm_object_t object, vm_pindex_t start, vm_pindex_t end, 2103 int options) 2104 { 2105 vm_page_t p, next; 2106 2107 VM_OBJECT_ASSERT_WLOCKED(object); 2108 KASSERT((object->flags & OBJ_UNMANAGED) == 0 || 2109 (options & (OBJPR_CLEANONLY | OBJPR_NOTMAPPED)) == OBJPR_NOTMAPPED, 2110 ("vm_object_page_remove: illegal options for object %p", object)); 2111 if (object->resident_page_count == 0) 2112 return; 2113 vm_object_pip_add(object, 1); 2114 again: 2115 p = vm_page_find_least(object, start); 2116 2117 /* 2118 * Here, the variable "p" is either (1) the page with the least pindex 2119 * greater than or equal to the parameter "start" or (2) NULL. 2120 */ 2121 for (; p != NULL && (p->pindex < end || end == 0); p = next) { 2122 next = TAILQ_NEXT(p, listq); 2123 2124 /* 2125 * Skip invalid pages if asked to do so. Try to avoid acquiring 2126 * the busy lock, as some consumers rely on this to avoid 2127 * deadlocks. 2128 * 2129 * A thread may concurrently transition the page from invalid to 2130 * valid using only the busy lock, so the result of this check 2131 * is immediately stale. It is up to consumers to handle this, 2132 * for instance by ensuring that all invalid->valid transitions 2133 * happen with a mutex held, as may be possible for a 2134 * filesystem. 2135 */ 2136 if ((options & OBJPR_VALIDONLY) != 0 && vm_page_none_valid(p)) 2137 continue; 2138 2139 /* 2140 * If the page is wired for any reason besides the existence 2141 * of managed, wired mappings, then it cannot be freed. For 2142 * example, fictitious pages, which represent device memory, 2143 * are inherently wired and cannot be freed. They can, 2144 * however, be invalidated if the option OBJPR_CLEANONLY is 2145 * not specified. 2146 */ 2147 if (vm_page_tryxbusy(p) == 0) { 2148 if (vm_page_busy_sleep(p, "vmopar", 0)) 2149 VM_OBJECT_WLOCK(object); 2150 goto again; 2151 } 2152 if ((options & OBJPR_VALIDONLY) != 0 && vm_page_none_valid(p)) { 2153 vm_page_xunbusy(p); 2154 continue; 2155 } 2156 if (vm_page_wired(p)) { 2157 wired: 2158 if ((options & OBJPR_NOTMAPPED) == 0 && 2159 object->ref_count != 0) 2160 pmap_remove_all(p); 2161 if ((options & OBJPR_CLEANONLY) == 0) { 2162 vm_page_invalid(p); 2163 vm_page_undirty(p); 2164 } 2165 vm_page_xunbusy(p); 2166 continue; 2167 } 2168 KASSERT((p->flags & PG_FICTITIOUS) == 0, 2169 ("vm_object_page_remove: page %p is fictitious", p)); 2170 if ((options & OBJPR_CLEANONLY) != 0 && 2171 !vm_page_none_valid(p)) { 2172 if ((options & OBJPR_NOTMAPPED) == 0 && 2173 object->ref_count != 0 && 2174 !vm_page_try_remove_write(p)) 2175 goto wired; 2176 if (p->dirty != 0) { 2177 vm_page_xunbusy(p); 2178 continue; 2179 } 2180 } 2181 if ((options & OBJPR_NOTMAPPED) == 0 && 2182 object->ref_count != 0 && !vm_page_try_remove_all(p)) 2183 goto wired; 2184 vm_page_free(p); 2185 } 2186 vm_object_pip_wakeup(object); 2187 2188 vm_pager_freespace(object, start, (end == 0 ? object->size : end) - 2189 start); 2190 } 2191 2192 /* 2193 * vm_object_page_noreuse: 2194 * 2195 * For the given object, attempt to move the specified pages to 2196 * the head of the inactive queue. This bypasses regular LRU 2197 * operation and allows the pages to be reused quickly under memory 2198 * pressure. If a page is wired for any reason, then it will not 2199 * be queued. Pages are specified by the range ["start", "end"). 2200 * As a special case, if "end" is zero, then the range extends from 2201 * "start" to the end of the object. 2202 * 2203 * This operation should only be performed on objects that 2204 * contain non-fictitious, managed pages. 2205 * 2206 * The object must be locked. 2207 */ 2208 void 2209 vm_object_page_noreuse(vm_object_t object, vm_pindex_t start, vm_pindex_t end) 2210 { 2211 vm_page_t p, next; 2212 2213 VM_OBJECT_ASSERT_LOCKED(object); 2214 KASSERT((object->flags & (OBJ_FICTITIOUS | OBJ_UNMANAGED)) == 0, 2215 ("vm_object_page_noreuse: illegal object %p", object)); 2216 if (object->resident_page_count == 0) 2217 return; 2218 p = vm_page_find_least(object, start); 2219 2220 /* 2221 * Here, the variable "p" is either (1) the page with the least pindex 2222 * greater than or equal to the parameter "start" or (2) NULL. 2223 */ 2224 for (; p != NULL && (p->pindex < end || end == 0); p = next) { 2225 next = TAILQ_NEXT(p, listq); 2226 vm_page_deactivate_noreuse(p); 2227 } 2228 } 2229 2230 /* 2231 * Populate the specified range of the object with valid pages. Returns 2232 * TRUE if the range is successfully populated and FALSE otherwise. 2233 * 2234 * Note: This function should be optimized to pass a larger array of 2235 * pages to vm_pager_get_pages() before it is applied to a non- 2236 * OBJT_DEVICE object. 2237 * 2238 * The object must be locked. 2239 */ 2240 boolean_t 2241 vm_object_populate(vm_object_t object, vm_pindex_t start, vm_pindex_t end) 2242 { 2243 vm_page_t m; 2244 vm_pindex_t pindex; 2245 int rv; 2246 2247 VM_OBJECT_ASSERT_WLOCKED(object); 2248 for (pindex = start; pindex < end; pindex++) { 2249 rv = vm_page_grab_valid(&m, object, pindex, VM_ALLOC_NORMAL); 2250 if (rv != VM_PAGER_OK) 2251 break; 2252 2253 /* 2254 * Keep "m" busy because a subsequent iteration may unlock 2255 * the object. 2256 */ 2257 } 2258 if (pindex > start) { 2259 m = vm_page_lookup(object, start); 2260 while (m != NULL && m->pindex < pindex) { 2261 vm_page_xunbusy(m); 2262 m = TAILQ_NEXT(m, listq); 2263 } 2264 } 2265 return (pindex == end); 2266 } 2267 2268 /* 2269 * Routine: vm_object_coalesce 2270 * Function: Coalesces two objects backing up adjoining 2271 * regions of memory into a single object. 2272 * 2273 * returns TRUE if objects were combined. 2274 * 2275 * NOTE: Only works at the moment if the second object is NULL - 2276 * if it's not, which object do we lock first? 2277 * 2278 * Parameters: 2279 * prev_object First object to coalesce 2280 * prev_offset Offset into prev_object 2281 * prev_size Size of reference to prev_object 2282 * next_size Size of reference to the second object 2283 * reserved Indicator that extension region has 2284 * swap accounted for 2285 * 2286 * Conditions: 2287 * The object must *not* be locked. 2288 */ 2289 boolean_t 2290 vm_object_coalesce(vm_object_t prev_object, vm_ooffset_t prev_offset, 2291 vm_size_t prev_size, vm_size_t next_size, boolean_t reserved) 2292 { 2293 vm_pindex_t next_pindex; 2294 2295 if (prev_object == NULL) 2296 return (TRUE); 2297 if ((prev_object->flags & OBJ_ANON) == 0) 2298 return (FALSE); 2299 2300 VM_OBJECT_WLOCK(prev_object); 2301 /* 2302 * Try to collapse the object first. 2303 */ 2304 vm_object_collapse(prev_object); 2305 2306 /* 2307 * Can't coalesce if: . more than one reference . paged out . shadows 2308 * another object . has a copy elsewhere (any of which mean that the 2309 * pages not mapped to prev_entry may be in use anyway) 2310 */ 2311 if (prev_object->backing_object != NULL) { 2312 VM_OBJECT_WUNLOCK(prev_object); 2313 return (FALSE); 2314 } 2315 2316 prev_size >>= PAGE_SHIFT; 2317 next_size >>= PAGE_SHIFT; 2318 next_pindex = OFF_TO_IDX(prev_offset) + prev_size; 2319 2320 if (prev_object->ref_count > 1 && 2321 prev_object->size != next_pindex && 2322 (prev_object->flags & OBJ_ONEMAPPING) == 0) { 2323 VM_OBJECT_WUNLOCK(prev_object); 2324 return (FALSE); 2325 } 2326 2327 /* 2328 * Account for the charge. 2329 */ 2330 if (prev_object->cred != NULL) { 2331 /* 2332 * If prev_object was charged, then this mapping, 2333 * although not charged now, may become writable 2334 * later. Non-NULL cred in the object would prevent 2335 * swap reservation during enabling of the write 2336 * access, so reserve swap now. Failed reservation 2337 * cause allocation of the separate object for the map 2338 * entry, and swap reservation for this entry is 2339 * managed in appropriate time. 2340 */ 2341 if (!reserved && !swap_reserve_by_cred(ptoa(next_size), 2342 prev_object->cred)) { 2343 VM_OBJECT_WUNLOCK(prev_object); 2344 return (FALSE); 2345 } 2346 prev_object->charge += ptoa(next_size); 2347 } 2348 2349 /* 2350 * Remove any pages that may still be in the object from a previous 2351 * deallocation. 2352 */ 2353 if (next_pindex < prev_object->size) { 2354 vm_object_page_remove(prev_object, next_pindex, next_pindex + 2355 next_size, 0); 2356 #if 0 2357 if (prev_object->cred != NULL) { 2358 KASSERT(prev_object->charge >= 2359 ptoa(prev_object->size - next_pindex), 2360 ("object %p overcharged 1 %jx %jx", prev_object, 2361 (uintmax_t)next_pindex, (uintmax_t)next_size)); 2362 prev_object->charge -= ptoa(prev_object->size - 2363 next_pindex); 2364 } 2365 #endif 2366 } 2367 2368 /* 2369 * Extend the object if necessary. 2370 */ 2371 if (next_pindex + next_size > prev_object->size) 2372 prev_object->size = next_pindex + next_size; 2373 2374 VM_OBJECT_WUNLOCK(prev_object); 2375 return (TRUE); 2376 } 2377 2378 void 2379 vm_object_set_writeable_dirty_(vm_object_t object) 2380 { 2381 atomic_add_int(&object->generation, 1); 2382 } 2383 2384 bool 2385 vm_object_mightbedirty_(vm_object_t object) 2386 { 2387 return (object->generation != object->cleangeneration); 2388 } 2389 2390 /* 2391 * vm_object_unwire: 2392 * 2393 * For each page offset within the specified range of the given object, 2394 * find the highest-level page in the shadow chain and unwire it. A page 2395 * must exist at every page offset, and the highest-level page must be 2396 * wired. 2397 */ 2398 void 2399 vm_object_unwire(vm_object_t object, vm_ooffset_t offset, vm_size_t length, 2400 uint8_t queue) 2401 { 2402 vm_object_t tobject, t1object; 2403 vm_page_t m, tm; 2404 vm_pindex_t end_pindex, pindex, tpindex; 2405 int depth, locked_depth; 2406 2407 KASSERT((offset & PAGE_MASK) == 0, 2408 ("vm_object_unwire: offset is not page aligned")); 2409 KASSERT((length & PAGE_MASK) == 0, 2410 ("vm_object_unwire: length is not a multiple of PAGE_SIZE")); 2411 /* The wired count of a fictitious page never changes. */ 2412 if ((object->flags & OBJ_FICTITIOUS) != 0) 2413 return; 2414 pindex = OFF_TO_IDX(offset); 2415 end_pindex = pindex + atop(length); 2416 again: 2417 locked_depth = 1; 2418 VM_OBJECT_RLOCK(object); 2419 m = vm_page_find_least(object, pindex); 2420 while (pindex < end_pindex) { 2421 if (m == NULL || pindex < m->pindex) { 2422 /* 2423 * The first object in the shadow chain doesn't 2424 * contain a page at the current index. Therefore, 2425 * the page must exist in a backing object. 2426 */ 2427 tobject = object; 2428 tpindex = pindex; 2429 depth = 0; 2430 do { 2431 tpindex += 2432 OFF_TO_IDX(tobject->backing_object_offset); 2433 tobject = tobject->backing_object; 2434 KASSERT(tobject != NULL, 2435 ("vm_object_unwire: missing page")); 2436 if ((tobject->flags & OBJ_FICTITIOUS) != 0) 2437 goto next_page; 2438 depth++; 2439 if (depth == locked_depth) { 2440 locked_depth++; 2441 VM_OBJECT_RLOCK(tobject); 2442 } 2443 } while ((tm = vm_page_lookup(tobject, tpindex)) == 2444 NULL); 2445 } else { 2446 tm = m; 2447 m = TAILQ_NEXT(m, listq); 2448 } 2449 if (vm_page_trysbusy(tm) == 0) { 2450 for (tobject = object; locked_depth >= 1; 2451 locked_depth--) { 2452 t1object = tobject->backing_object; 2453 if (tm->object != tobject) 2454 VM_OBJECT_RUNLOCK(tobject); 2455 tobject = t1object; 2456 } 2457 tobject = tm->object; 2458 if (!vm_page_busy_sleep(tm, "unwbo", 2459 VM_ALLOC_IGN_SBUSY)) 2460 VM_OBJECT_RUNLOCK(tobject); 2461 goto again; 2462 } 2463 vm_page_unwire(tm, queue); 2464 vm_page_sunbusy(tm); 2465 next_page: 2466 pindex++; 2467 } 2468 /* Release the accumulated object locks. */ 2469 for (tobject = object; locked_depth >= 1; locked_depth--) { 2470 t1object = tobject->backing_object; 2471 VM_OBJECT_RUNLOCK(tobject); 2472 tobject = t1object; 2473 } 2474 } 2475 2476 /* 2477 * Return the vnode for the given object, or NULL if none exists. 2478 * For tmpfs objects, the function may return NULL if there is 2479 * no vnode allocated at the time of the call. 2480 */ 2481 struct vnode * 2482 vm_object_vnode(vm_object_t object) 2483 { 2484 struct vnode *vp; 2485 2486 VM_OBJECT_ASSERT_LOCKED(object); 2487 vm_pager_getvp(object, &vp, NULL); 2488 return (vp); 2489 } 2490 2491 /* 2492 * Busy the vm object. This prevents new pages belonging to the object from 2493 * becoming busy. Existing pages persist as busy. Callers are responsible 2494 * for checking page state before proceeding. 2495 */ 2496 void 2497 vm_object_busy(vm_object_t obj) 2498 { 2499 2500 VM_OBJECT_ASSERT_LOCKED(obj); 2501 2502 blockcount_acquire(&obj->busy, 1); 2503 /* The fence is required to order loads of page busy. */ 2504 atomic_thread_fence_acq_rel(); 2505 } 2506 2507 void 2508 vm_object_unbusy(vm_object_t obj) 2509 { 2510 2511 blockcount_release(&obj->busy, 1); 2512 } 2513 2514 void 2515 vm_object_busy_wait(vm_object_t obj, const char *wmesg) 2516 { 2517 2518 VM_OBJECT_ASSERT_UNLOCKED(obj); 2519 2520 (void)blockcount_sleep(&obj->busy, NULL, wmesg, PVM); 2521 } 2522 2523 /* 2524 * This function aims to determine if the object is mapped, 2525 * specifically, if it is referenced by a vm_map_entry. Because 2526 * objects occasionally acquire transient references that do not 2527 * represent a mapping, the method used here is inexact. However, it 2528 * has very low overhead and is good enough for the advisory 2529 * vm.vmtotal sysctl. 2530 */ 2531 bool 2532 vm_object_is_active(vm_object_t obj) 2533 { 2534 2535 return (obj->ref_count > atomic_load_int(&obj->shadow_count)); 2536 } 2537 2538 static int 2539 vm_object_list_handler(struct sysctl_req *req, bool swap_only) 2540 { 2541 struct kinfo_vmobject *kvo; 2542 char *fullpath, *freepath; 2543 struct vnode *vp; 2544 struct vattr va; 2545 vm_object_t obj; 2546 vm_page_t m; 2547 u_long sp; 2548 int count, error; 2549 2550 if (req->oldptr == NULL) { 2551 /* 2552 * If an old buffer has not been provided, generate an 2553 * estimate of the space needed for a subsequent call. 2554 */ 2555 mtx_lock(&vm_object_list_mtx); 2556 count = 0; 2557 TAILQ_FOREACH(obj, &vm_object_list, object_list) { 2558 if (obj->type == OBJT_DEAD) 2559 continue; 2560 count++; 2561 } 2562 mtx_unlock(&vm_object_list_mtx); 2563 return (SYSCTL_OUT(req, NULL, sizeof(struct kinfo_vmobject) * 2564 count * 11 / 10)); 2565 } 2566 2567 kvo = malloc(sizeof(*kvo), M_TEMP, M_WAITOK); 2568 error = 0; 2569 2570 /* 2571 * VM objects are type stable and are never removed from the 2572 * list once added. This allows us to safely read obj->object_list 2573 * after reacquiring the VM object lock. 2574 */ 2575 mtx_lock(&vm_object_list_mtx); 2576 TAILQ_FOREACH(obj, &vm_object_list, object_list) { 2577 if (obj->type == OBJT_DEAD || 2578 (swap_only && (obj->flags & (OBJ_ANON | OBJ_SWAP)) == 0)) 2579 continue; 2580 VM_OBJECT_RLOCK(obj); 2581 if (obj->type == OBJT_DEAD || 2582 (swap_only && (obj->flags & (OBJ_ANON | OBJ_SWAP)) == 0)) { 2583 VM_OBJECT_RUNLOCK(obj); 2584 continue; 2585 } 2586 mtx_unlock(&vm_object_list_mtx); 2587 kvo->kvo_size = ptoa(obj->size); 2588 kvo->kvo_resident = obj->resident_page_count; 2589 kvo->kvo_ref_count = obj->ref_count; 2590 kvo->kvo_shadow_count = atomic_load_int(&obj->shadow_count); 2591 kvo->kvo_memattr = obj->memattr; 2592 kvo->kvo_active = 0; 2593 kvo->kvo_inactive = 0; 2594 if (!swap_only) { 2595 TAILQ_FOREACH(m, &obj->memq, listq) { 2596 /* 2597 * A page may belong to the object but be 2598 * dequeued and set to PQ_NONE while the 2599 * object lock is not held. This makes the 2600 * reads of m->queue below racy, and we do not 2601 * count pages set to PQ_NONE. However, this 2602 * sysctl is only meant to give an 2603 * approximation of the system anyway. 2604 */ 2605 if (m->a.queue == PQ_ACTIVE) 2606 kvo->kvo_active++; 2607 else if (m->a.queue == PQ_INACTIVE) 2608 kvo->kvo_inactive++; 2609 } 2610 } 2611 2612 kvo->kvo_vn_fileid = 0; 2613 kvo->kvo_vn_fsid = 0; 2614 kvo->kvo_vn_fsid_freebsd11 = 0; 2615 freepath = NULL; 2616 fullpath = ""; 2617 vp = NULL; 2618 kvo->kvo_type = vm_object_kvme_type(obj, swap_only ? NULL : &vp); 2619 if (vp != NULL) { 2620 vref(vp); 2621 } else if ((obj->flags & OBJ_ANON) != 0) { 2622 MPASS(kvo->kvo_type == KVME_TYPE_DEFAULT || 2623 kvo->kvo_type == KVME_TYPE_SWAP); 2624 kvo->kvo_me = (uintptr_t)obj; 2625 /* tmpfs objs are reported as vnodes */ 2626 kvo->kvo_backing_obj = (uintptr_t)obj->backing_object; 2627 sp = swap_pager_swapped_pages(obj); 2628 kvo->kvo_swapped = sp > UINT32_MAX ? UINT32_MAX : sp; 2629 } 2630 VM_OBJECT_RUNLOCK(obj); 2631 if (vp != NULL) { 2632 vn_fullpath(vp, &fullpath, &freepath); 2633 vn_lock(vp, LK_SHARED | LK_RETRY); 2634 if (VOP_GETATTR(vp, &va, curthread->td_ucred) == 0) { 2635 kvo->kvo_vn_fileid = va.va_fileid; 2636 kvo->kvo_vn_fsid = va.va_fsid; 2637 kvo->kvo_vn_fsid_freebsd11 = va.va_fsid; 2638 /* truncate */ 2639 } 2640 vput(vp); 2641 } 2642 2643 strlcpy(kvo->kvo_path, fullpath, sizeof(kvo->kvo_path)); 2644 if (freepath != NULL) 2645 free(freepath, M_TEMP); 2646 2647 /* Pack record size down */ 2648 kvo->kvo_structsize = offsetof(struct kinfo_vmobject, kvo_path) 2649 + strlen(kvo->kvo_path) + 1; 2650 kvo->kvo_structsize = roundup(kvo->kvo_structsize, 2651 sizeof(uint64_t)); 2652 error = SYSCTL_OUT(req, kvo, kvo->kvo_structsize); 2653 maybe_yield(); 2654 mtx_lock(&vm_object_list_mtx); 2655 if (error) 2656 break; 2657 } 2658 mtx_unlock(&vm_object_list_mtx); 2659 free(kvo, M_TEMP); 2660 return (error); 2661 } 2662 2663 static int 2664 sysctl_vm_object_list(SYSCTL_HANDLER_ARGS) 2665 { 2666 return (vm_object_list_handler(req, false)); 2667 } 2668 2669 SYSCTL_PROC(_vm, OID_AUTO, objects, CTLTYPE_STRUCT | CTLFLAG_RW | CTLFLAG_SKIP | 2670 CTLFLAG_MPSAFE, NULL, 0, sysctl_vm_object_list, "S,kinfo_vmobject", 2671 "List of VM objects"); 2672 2673 static int 2674 sysctl_vm_object_list_swap(SYSCTL_HANDLER_ARGS) 2675 { 2676 return (vm_object_list_handler(req, true)); 2677 } 2678 2679 /* 2680 * This sysctl returns list of the anonymous or swap objects. Intent 2681 * is to provide stripped optimized list useful to analyze swap use. 2682 * Since technically non-swap (default) objects participate in the 2683 * shadow chains, and are converted to swap type as needed by swap 2684 * pager, we must report them. 2685 */ 2686 SYSCTL_PROC(_vm, OID_AUTO, swap_objects, 2687 CTLTYPE_STRUCT | CTLFLAG_RW | CTLFLAG_SKIP | CTLFLAG_MPSAFE, NULL, 0, 2688 sysctl_vm_object_list_swap, "S,kinfo_vmobject", 2689 "List of swap VM objects"); 2690 2691 #include "opt_ddb.h" 2692 #ifdef DDB 2693 #include <sys/kernel.h> 2694 2695 #include <sys/cons.h> 2696 2697 #include <ddb/ddb.h> 2698 2699 static int 2700 _vm_object_in_map(vm_map_t map, vm_object_t object, vm_map_entry_t entry) 2701 { 2702 vm_map_t tmpm; 2703 vm_map_entry_t tmpe; 2704 vm_object_t obj; 2705 2706 if (map == 0) 2707 return 0; 2708 2709 if (entry == 0) { 2710 VM_MAP_ENTRY_FOREACH(tmpe, map) { 2711 if (_vm_object_in_map(map, object, tmpe)) { 2712 return 1; 2713 } 2714 } 2715 } else if (entry->eflags & MAP_ENTRY_IS_SUB_MAP) { 2716 tmpm = entry->object.sub_map; 2717 VM_MAP_ENTRY_FOREACH(tmpe, tmpm) { 2718 if (_vm_object_in_map(tmpm, object, tmpe)) { 2719 return 1; 2720 } 2721 } 2722 } else if ((obj = entry->object.vm_object) != NULL) { 2723 for (; obj; obj = obj->backing_object) 2724 if (obj == object) { 2725 return 1; 2726 } 2727 } 2728 return 0; 2729 } 2730 2731 static int 2732 vm_object_in_map(vm_object_t object) 2733 { 2734 struct proc *p; 2735 2736 /* sx_slock(&allproc_lock); */ 2737 FOREACH_PROC_IN_SYSTEM(p) { 2738 if (!p->p_vmspace /* || (p->p_flag & (P_SYSTEM|P_WEXIT)) */) 2739 continue; 2740 if (_vm_object_in_map(&p->p_vmspace->vm_map, object, 0)) { 2741 /* sx_sunlock(&allproc_lock); */ 2742 return 1; 2743 } 2744 } 2745 /* sx_sunlock(&allproc_lock); */ 2746 if (_vm_object_in_map(kernel_map, object, 0)) 2747 return 1; 2748 return 0; 2749 } 2750 2751 DB_SHOW_COMMAND(vmochk, vm_object_check) 2752 { 2753 vm_object_t object; 2754 2755 /* 2756 * make sure that internal objs are in a map somewhere 2757 * and none have zero ref counts. 2758 */ 2759 TAILQ_FOREACH(object, &vm_object_list, object_list) { 2760 if ((object->flags & OBJ_ANON) != 0) { 2761 if (object->ref_count == 0) { 2762 db_printf("vmochk: internal obj has zero ref count: %ld\n", 2763 (long)object->size); 2764 } 2765 if (!vm_object_in_map(object)) { 2766 db_printf( 2767 "vmochk: internal obj is not in a map: " 2768 "ref: %d, size: %lu: 0x%lx, backing_object: %p\n", 2769 object->ref_count, (u_long)object->size, 2770 (u_long)object->size, 2771 (void *)object->backing_object); 2772 } 2773 } 2774 if (db_pager_quit) 2775 return; 2776 } 2777 } 2778 2779 /* 2780 * vm_object_print: [ debug ] 2781 */ 2782 DB_SHOW_COMMAND(object, vm_object_print_static) 2783 { 2784 /* XXX convert args. */ 2785 vm_object_t object = (vm_object_t)addr; 2786 boolean_t full = have_addr; 2787 2788 vm_page_t p; 2789 2790 /* XXX count is an (unused) arg. Avoid shadowing it. */ 2791 #define count was_count 2792 2793 int count; 2794 2795 if (object == NULL) 2796 return; 2797 2798 db_iprintf( 2799 "Object %p: type=%d, size=0x%jx, res=%d, ref=%d, flags=0x%x ruid %d charge %jx\n", 2800 object, (int)object->type, (uintmax_t)object->size, 2801 object->resident_page_count, object->ref_count, object->flags, 2802 object->cred ? object->cred->cr_ruid : -1, (uintmax_t)object->charge); 2803 db_iprintf(" sref=%d, backing_object(%d)=(%p)+0x%jx\n", 2804 atomic_load_int(&object->shadow_count), 2805 object->backing_object ? object->backing_object->ref_count : 0, 2806 object->backing_object, (uintmax_t)object->backing_object_offset); 2807 2808 if (!full) 2809 return; 2810 2811 db_indent += 2; 2812 count = 0; 2813 TAILQ_FOREACH(p, &object->memq, listq) { 2814 if (count == 0) 2815 db_iprintf("memory:="); 2816 else if (count == 6) { 2817 db_printf("\n"); 2818 db_iprintf(" ..."); 2819 count = 0; 2820 } else 2821 db_printf(","); 2822 count++; 2823 2824 db_printf("(off=0x%jx,page=0x%jx)", 2825 (uintmax_t)p->pindex, (uintmax_t)VM_PAGE_TO_PHYS(p)); 2826 2827 if (db_pager_quit) 2828 break; 2829 } 2830 if (count != 0) 2831 db_printf("\n"); 2832 db_indent -= 2; 2833 } 2834 2835 /* XXX. */ 2836 #undef count 2837 2838 /* XXX need this non-static entry for calling from vm_map_print. */ 2839 void 2840 vm_object_print( 2841 /* db_expr_t */ long addr, 2842 boolean_t have_addr, 2843 /* db_expr_t */ long count, 2844 char *modif) 2845 { 2846 vm_object_print_static(addr, have_addr, count, modif); 2847 } 2848 2849 DB_SHOW_COMMAND(vmopag, vm_object_print_pages) 2850 { 2851 vm_object_t object; 2852 vm_pindex_t fidx; 2853 vm_paddr_t pa; 2854 vm_page_t m, prev_m; 2855 int rcount; 2856 2857 TAILQ_FOREACH(object, &vm_object_list, object_list) { 2858 db_printf("new object: %p\n", (void *)object); 2859 if (db_pager_quit) 2860 return; 2861 2862 rcount = 0; 2863 fidx = 0; 2864 pa = -1; 2865 TAILQ_FOREACH(m, &object->memq, listq) { 2866 if (m->pindex > 128) 2867 break; 2868 if ((prev_m = TAILQ_PREV(m, pglist, listq)) != NULL && 2869 prev_m->pindex + 1 != m->pindex) { 2870 if (rcount) { 2871 db_printf(" index(%ld)run(%d)pa(0x%lx)\n", 2872 (long)fidx, rcount, (long)pa); 2873 if (db_pager_quit) 2874 return; 2875 rcount = 0; 2876 } 2877 } 2878 if (rcount && 2879 (VM_PAGE_TO_PHYS(m) == pa + rcount * PAGE_SIZE)) { 2880 ++rcount; 2881 continue; 2882 } 2883 if (rcount) { 2884 db_printf(" index(%ld)run(%d)pa(0x%lx)\n", 2885 (long)fidx, rcount, (long)pa); 2886 if (db_pager_quit) 2887 return; 2888 } 2889 fidx = m->pindex; 2890 pa = VM_PAGE_TO_PHYS(m); 2891 rcount = 1; 2892 } 2893 if (rcount) { 2894 db_printf(" index(%ld)run(%d)pa(0x%lx)\n", 2895 (long)fidx, rcount, (long)pa); 2896 if (db_pager_quit) 2897 return; 2898 } 2899 } 2900 } 2901 #endif /* DDB */ 2902