1 /*- 2 * SPDX-License-Identifier: (BSD-3-Clause AND MIT-CMU) 3 * 4 * Copyright (c) 1991, 1993 5 * The Regents of the University of California. All rights reserved. 6 * 7 * This code is derived from software contributed to Berkeley by 8 * The Mach Operating System project at Carnegie-Mellon University. 9 * 10 * Redistribution and use in source and binary forms, with or without 11 * modification, are permitted provided that the following conditions 12 * are met: 13 * 1. Redistributions of source code must retain the above copyright 14 * notice, this list of conditions and the following disclaimer. 15 * 2. Redistributions in binary form must reproduce the above copyright 16 * notice, this list of conditions and the following disclaimer in the 17 * documentation and/or other materials provided with the distribution. 18 * 3. Neither the name of the University nor the names of its contributors 19 * may be used to endorse or promote products derived from this software 20 * without specific prior written permission. 21 * 22 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 23 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 24 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 25 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 26 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 27 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 28 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 29 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 30 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 31 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 32 * SUCH DAMAGE. 33 * 34 * from: @(#)vm_object.c 8.5 (Berkeley) 3/22/94 35 * 36 * 37 * Copyright (c) 1987, 1990 Carnegie-Mellon University. 38 * All rights reserved. 39 * 40 * Authors: Avadis Tevanian, Jr., Michael Wayne Young 41 * 42 * Permission to use, copy, modify and distribute this software and 43 * its documentation is hereby granted, provided that both the copyright 44 * notice and this permission notice appear in all copies of the 45 * software, derivative works or modified versions, and any portions 46 * thereof, and that both notices appear in supporting documentation. 47 * 48 * CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS" 49 * CONDITION. CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND 50 * FOR ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE. 51 * 52 * Carnegie Mellon requests users of this software to return to 53 * 54 * Software Distribution Coordinator or Software.Distribution@CS.CMU.EDU 55 * School of Computer Science 56 * Carnegie Mellon University 57 * Pittsburgh PA 15213-3890 58 * 59 * any improvements or extensions that they make and grant Carnegie the 60 * rights to redistribute these changes. 61 */ 62 63 /* 64 * Virtual memory object module. 65 */ 66 67 #include <sys/cdefs.h> 68 __FBSDID("$FreeBSD$"); 69 70 #include "opt_vm.h" 71 72 #include <sys/param.h> 73 #include <sys/systm.h> 74 #include <sys/blockcount.h> 75 #include <sys/cpuset.h> 76 #include <sys/limits.h> 77 #include <sys/lock.h> 78 #include <sys/mman.h> 79 #include <sys/mount.h> 80 #include <sys/kernel.h> 81 #include <sys/pctrie.h> 82 #include <sys/sysctl.h> 83 #include <sys/mutex.h> 84 #include <sys/proc.h> /* for curproc, pageproc */ 85 #include <sys/refcount.h> 86 #include <sys/socket.h> 87 #include <sys/resourcevar.h> 88 #include <sys/refcount.h> 89 #include <sys/rwlock.h> 90 #include <sys/user.h> 91 #include <sys/vnode.h> 92 #include <sys/vmmeter.h> 93 #include <sys/sx.h> 94 95 #include <vm/vm.h> 96 #include <vm/vm_param.h> 97 #include <vm/pmap.h> 98 #include <vm/vm_map.h> 99 #include <vm/vm_object.h> 100 #include <vm/vm_page.h> 101 #include <vm/vm_pageout.h> 102 #include <vm/vm_pager.h> 103 #include <vm/vm_phys.h> 104 #include <vm/vm_pagequeue.h> 105 #include <vm/swap_pager.h> 106 #include <vm/vm_kern.h> 107 #include <vm/vm_extern.h> 108 #include <vm/vm_radix.h> 109 #include <vm/vm_reserv.h> 110 #include <vm/uma.h> 111 112 static int old_msync; 113 SYSCTL_INT(_vm, OID_AUTO, old_msync, CTLFLAG_RW, &old_msync, 0, 114 "Use old (insecure) msync behavior"); 115 116 static int vm_object_page_collect_flush(vm_object_t object, vm_page_t p, 117 int pagerflags, int flags, boolean_t *allclean, 118 boolean_t *eio); 119 static boolean_t vm_object_page_remove_write(vm_page_t p, int flags, 120 boolean_t *allclean); 121 static void vm_object_backing_remove(vm_object_t object); 122 123 /* 124 * Virtual memory objects maintain the actual data 125 * associated with allocated virtual memory. A given 126 * page of memory exists within exactly one object. 127 * 128 * An object is only deallocated when all "references" 129 * are given up. Only one "reference" to a given 130 * region of an object should be writeable. 131 * 132 * Associated with each object is a list of all resident 133 * memory pages belonging to that object; this list is 134 * maintained by the "vm_page" module, and locked by the object's 135 * lock. 136 * 137 * Each object also records a "pager" routine which is 138 * used to retrieve (and store) pages to the proper backing 139 * storage. In addition, objects may be backed by other 140 * objects from which they were virtual-copied. 141 * 142 * The only items within the object structure which are 143 * modified after time of creation are: 144 * reference count locked by object's lock 145 * pager routine locked by object's lock 146 * 147 */ 148 149 struct object_q vm_object_list; 150 struct mtx vm_object_list_mtx; /* lock for object list and count */ 151 152 struct vm_object kernel_object_store; 153 154 static SYSCTL_NODE(_vm_stats, OID_AUTO, object, CTLFLAG_RD | CTLFLAG_MPSAFE, 0, 155 "VM object stats"); 156 157 static COUNTER_U64_DEFINE_EARLY(object_collapses); 158 SYSCTL_COUNTER_U64(_vm_stats_object, OID_AUTO, collapses, CTLFLAG_RD, 159 &object_collapses, 160 "VM object collapses"); 161 162 static COUNTER_U64_DEFINE_EARLY(object_bypasses); 163 SYSCTL_COUNTER_U64(_vm_stats_object, OID_AUTO, bypasses, CTLFLAG_RD, 164 &object_bypasses, 165 "VM object bypasses"); 166 167 static COUNTER_U64_DEFINE_EARLY(object_collapse_waits); 168 SYSCTL_COUNTER_U64(_vm_stats_object, OID_AUTO, collapse_waits, CTLFLAG_RD, 169 &object_collapse_waits, 170 "Number of sleeps for collapse"); 171 172 static uma_zone_t obj_zone; 173 174 static int vm_object_zinit(void *mem, int size, int flags); 175 176 #ifdef INVARIANTS 177 static void vm_object_zdtor(void *mem, int size, void *arg); 178 179 static void 180 vm_object_zdtor(void *mem, int size, void *arg) 181 { 182 vm_object_t object; 183 184 object = (vm_object_t)mem; 185 KASSERT(object->ref_count == 0, 186 ("object %p ref_count = %d", object, object->ref_count)); 187 KASSERT(TAILQ_EMPTY(&object->memq), 188 ("object %p has resident pages in its memq", object)); 189 KASSERT(vm_radix_is_empty(&object->rtree), 190 ("object %p has resident pages in its trie", object)); 191 #if VM_NRESERVLEVEL > 0 192 KASSERT(LIST_EMPTY(&object->rvq), 193 ("object %p has reservations", 194 object)); 195 #endif 196 KASSERT(!vm_object_busied(object), 197 ("object %p busy = %d", object, blockcount_read(&object->busy))); 198 KASSERT(object->resident_page_count == 0, 199 ("object %p resident_page_count = %d", 200 object, object->resident_page_count)); 201 KASSERT(atomic_load_int(&object->shadow_count) == 0, 202 ("object %p shadow_count = %d", 203 object, atomic_load_int(&object->shadow_count))); 204 KASSERT(object->type == OBJT_DEAD, 205 ("object %p has non-dead type %d", 206 object, object->type)); 207 KASSERT(object->charge == 0 && object->cred == NULL, 208 ("object %p has non-zero charge %ju (%p)", 209 object, (uintmax_t)object->charge, object->cred)); 210 } 211 #endif 212 213 static int 214 vm_object_zinit(void *mem, int size, int flags) 215 { 216 vm_object_t object; 217 218 object = (vm_object_t)mem; 219 rw_init_flags(&object->lock, "vm object", RW_DUPOK | RW_NEW); 220 221 /* These are true for any object that has been freed */ 222 object->type = OBJT_DEAD; 223 vm_radix_init(&object->rtree); 224 refcount_init(&object->ref_count, 0); 225 blockcount_init(&object->paging_in_progress); 226 blockcount_init(&object->busy); 227 object->resident_page_count = 0; 228 atomic_store_int(&object->shadow_count, 0); 229 object->flags = OBJ_DEAD; 230 231 mtx_lock(&vm_object_list_mtx); 232 TAILQ_INSERT_TAIL(&vm_object_list, object, object_list); 233 mtx_unlock(&vm_object_list_mtx); 234 return (0); 235 } 236 237 static void 238 _vm_object_allocate(objtype_t type, vm_pindex_t size, u_short flags, 239 vm_object_t object, void *handle) 240 { 241 242 TAILQ_INIT(&object->memq); 243 LIST_INIT(&object->shadow_head); 244 245 object->type = type; 246 object->flags = flags; 247 if ((flags & OBJ_SWAP) != 0) 248 pctrie_init(&object->un_pager.swp.swp_blks); 249 250 /* 251 * Ensure that swap_pager_swapoff() iteration over object_list 252 * sees up to date type and pctrie head if it observed 253 * non-dead object. 254 */ 255 atomic_thread_fence_rel(); 256 257 object->pg_color = 0; 258 object->size = size; 259 object->domain.dr_policy = NULL; 260 object->generation = 1; 261 object->cleangeneration = 1; 262 refcount_init(&object->ref_count, 1); 263 object->memattr = VM_MEMATTR_DEFAULT; 264 object->cred = NULL; 265 object->charge = 0; 266 object->handle = handle; 267 object->backing_object = NULL; 268 object->backing_object_offset = (vm_ooffset_t) 0; 269 #if VM_NRESERVLEVEL > 0 270 LIST_INIT(&object->rvq); 271 #endif 272 umtx_shm_object_init(object); 273 } 274 275 /* 276 * vm_object_init: 277 * 278 * Initialize the VM objects module. 279 */ 280 void 281 vm_object_init(void) 282 { 283 TAILQ_INIT(&vm_object_list); 284 mtx_init(&vm_object_list_mtx, "vm object_list", NULL, MTX_DEF); 285 286 rw_init(&kernel_object->lock, "kernel vm object"); 287 _vm_object_allocate(OBJT_PHYS, atop(VM_MAX_KERNEL_ADDRESS - 288 VM_MIN_KERNEL_ADDRESS), OBJ_UNMANAGED, kernel_object, NULL); 289 #if VM_NRESERVLEVEL > 0 290 kernel_object->flags |= OBJ_COLORED; 291 kernel_object->pg_color = (u_short)atop(VM_MIN_KERNEL_ADDRESS); 292 #endif 293 kernel_object->un_pager.phys.ops = &default_phys_pg_ops; 294 295 /* 296 * The lock portion of struct vm_object must be type stable due 297 * to vm_pageout_fallback_object_lock locking a vm object 298 * without holding any references to it. 299 * 300 * paging_in_progress is valid always. Lockless references to 301 * the objects may acquire pip and then check OBJ_DEAD. 302 */ 303 obj_zone = uma_zcreate("VM OBJECT", sizeof (struct vm_object), NULL, 304 #ifdef INVARIANTS 305 vm_object_zdtor, 306 #else 307 NULL, 308 #endif 309 vm_object_zinit, NULL, UMA_ALIGN_PTR, UMA_ZONE_NOFREE); 310 311 vm_radix_zinit(); 312 } 313 314 void 315 vm_object_clear_flag(vm_object_t object, u_short bits) 316 { 317 318 VM_OBJECT_ASSERT_WLOCKED(object); 319 object->flags &= ~bits; 320 } 321 322 /* 323 * Sets the default memory attribute for the specified object. Pages 324 * that are allocated to this object are by default assigned this memory 325 * attribute. 326 * 327 * Presently, this function must be called before any pages are allocated 328 * to the object. In the future, this requirement may be relaxed for 329 * "default" and "swap" objects. 330 */ 331 int 332 vm_object_set_memattr(vm_object_t object, vm_memattr_t memattr) 333 { 334 335 VM_OBJECT_ASSERT_WLOCKED(object); 336 337 if (object->type == OBJT_DEAD) 338 return (KERN_INVALID_ARGUMENT); 339 if (!TAILQ_EMPTY(&object->memq)) 340 return (KERN_FAILURE); 341 342 object->memattr = memattr; 343 return (KERN_SUCCESS); 344 } 345 346 void 347 vm_object_pip_add(vm_object_t object, short i) 348 { 349 350 if (i > 0) 351 blockcount_acquire(&object->paging_in_progress, i); 352 } 353 354 void 355 vm_object_pip_wakeup(vm_object_t object) 356 { 357 358 vm_object_pip_wakeupn(object, 1); 359 } 360 361 void 362 vm_object_pip_wakeupn(vm_object_t object, short i) 363 { 364 365 if (i > 0) 366 blockcount_release(&object->paging_in_progress, i); 367 } 368 369 /* 370 * Atomically drop the object lock and wait for pip to drain. This protects 371 * from sleep/wakeup races due to identity changes. The lock is not re-acquired 372 * on return. 373 */ 374 static void 375 vm_object_pip_sleep(vm_object_t object, const char *waitid) 376 { 377 378 (void)blockcount_sleep(&object->paging_in_progress, &object->lock, 379 waitid, PVM | PDROP); 380 } 381 382 void 383 vm_object_pip_wait(vm_object_t object, const char *waitid) 384 { 385 386 VM_OBJECT_ASSERT_WLOCKED(object); 387 388 blockcount_wait(&object->paging_in_progress, &object->lock, waitid, 389 PVM); 390 } 391 392 void 393 vm_object_pip_wait_unlocked(vm_object_t object, const char *waitid) 394 { 395 396 VM_OBJECT_ASSERT_UNLOCKED(object); 397 398 blockcount_wait(&object->paging_in_progress, NULL, waitid, PVM); 399 } 400 401 /* 402 * vm_object_allocate: 403 * 404 * Returns a new object with the given size. 405 */ 406 vm_object_t 407 vm_object_allocate(objtype_t type, vm_pindex_t size) 408 { 409 vm_object_t object; 410 u_short flags; 411 412 switch (type) { 413 case OBJT_DEAD: 414 panic("vm_object_allocate: can't create OBJT_DEAD"); 415 case OBJT_DEFAULT: 416 flags = OBJ_COLORED; 417 break; 418 case OBJT_SWAP: 419 flags = OBJ_COLORED | OBJ_SWAP; 420 break; 421 case OBJT_DEVICE: 422 case OBJT_SG: 423 flags = OBJ_FICTITIOUS | OBJ_UNMANAGED; 424 break; 425 case OBJT_MGTDEVICE: 426 flags = OBJ_FICTITIOUS; 427 break; 428 case OBJT_PHYS: 429 flags = OBJ_UNMANAGED; 430 break; 431 case OBJT_VNODE: 432 flags = 0; 433 break; 434 default: 435 panic("vm_object_allocate: type %d is undefined or dynamic", 436 type); 437 } 438 object = (vm_object_t)uma_zalloc(obj_zone, M_WAITOK); 439 _vm_object_allocate(type, size, flags, object, NULL); 440 441 return (object); 442 } 443 444 vm_object_t 445 vm_object_allocate_dyn(objtype_t dyntype, vm_pindex_t size, u_short flags) 446 { 447 vm_object_t object; 448 449 MPASS(dyntype >= OBJT_FIRST_DYN /* && dyntype < nitems(pagertab) */); 450 object = (vm_object_t)uma_zalloc(obj_zone, M_WAITOK); 451 _vm_object_allocate(dyntype, size, flags, object, NULL); 452 453 return (object); 454 } 455 456 /* 457 * vm_object_allocate_anon: 458 * 459 * Returns a new default object of the given size and marked as 460 * anonymous memory for special split/collapse handling. Color 461 * to be initialized by the caller. 462 */ 463 vm_object_t 464 vm_object_allocate_anon(vm_pindex_t size, vm_object_t backing_object, 465 struct ucred *cred, vm_size_t charge) 466 { 467 vm_object_t handle, object; 468 469 if (backing_object == NULL) 470 handle = NULL; 471 else if ((backing_object->flags & OBJ_ANON) != 0) 472 handle = backing_object->handle; 473 else 474 handle = backing_object; 475 object = uma_zalloc(obj_zone, M_WAITOK); 476 _vm_object_allocate(OBJT_DEFAULT, size, OBJ_ANON | OBJ_ONEMAPPING, 477 object, handle); 478 object->cred = cred; 479 object->charge = cred != NULL ? charge : 0; 480 return (object); 481 } 482 483 static void 484 vm_object_reference_vnode(vm_object_t object) 485 { 486 u_int old; 487 488 /* 489 * vnode objects need the lock for the first reference 490 * to serialize with vnode_object_deallocate(). 491 */ 492 if (!refcount_acquire_if_gt(&object->ref_count, 0)) { 493 VM_OBJECT_RLOCK(object); 494 old = refcount_acquire(&object->ref_count); 495 if (object->type == OBJT_VNODE && old == 0) 496 vref(object->handle); 497 VM_OBJECT_RUNLOCK(object); 498 } 499 } 500 501 /* 502 * vm_object_reference: 503 * 504 * Acquires a reference to the given object. 505 */ 506 void 507 vm_object_reference(vm_object_t object) 508 { 509 510 if (object == NULL) 511 return; 512 513 if (object->type == OBJT_VNODE) 514 vm_object_reference_vnode(object); 515 else 516 refcount_acquire(&object->ref_count); 517 KASSERT((object->flags & OBJ_DEAD) == 0, 518 ("vm_object_reference: Referenced dead object.")); 519 } 520 521 /* 522 * vm_object_reference_locked: 523 * 524 * Gets another reference to the given object. 525 * 526 * The object must be locked. 527 */ 528 void 529 vm_object_reference_locked(vm_object_t object) 530 { 531 u_int old; 532 533 VM_OBJECT_ASSERT_LOCKED(object); 534 old = refcount_acquire(&object->ref_count); 535 if (object->type == OBJT_VNODE && old == 0) 536 vref(object->handle); 537 KASSERT((object->flags & OBJ_DEAD) == 0, 538 ("vm_object_reference: Referenced dead object.")); 539 } 540 541 /* 542 * Handle deallocating an object of type OBJT_VNODE. 543 */ 544 static void 545 vm_object_deallocate_vnode(vm_object_t object) 546 { 547 struct vnode *vp = (struct vnode *) object->handle; 548 bool last; 549 550 KASSERT(object->type == OBJT_VNODE, 551 ("vm_object_deallocate_vnode: not a vnode object")); 552 KASSERT(vp != NULL, ("vm_object_deallocate_vnode: missing vp")); 553 554 /* Object lock to protect handle lookup. */ 555 last = refcount_release(&object->ref_count); 556 VM_OBJECT_RUNLOCK(object); 557 558 if (!last) 559 return; 560 561 if (!umtx_shm_vnobj_persistent) 562 umtx_shm_object_terminated(object); 563 564 /* vrele may need the vnode lock. */ 565 vrele(vp); 566 } 567 568 /* 569 * We dropped a reference on an object and discovered that it had a 570 * single remaining shadow. This is a sibling of the reference we 571 * dropped. Attempt to collapse the sibling and backing object. 572 */ 573 static vm_object_t 574 vm_object_deallocate_anon(vm_object_t backing_object) 575 { 576 vm_object_t object; 577 578 /* Fetch the final shadow. */ 579 object = LIST_FIRST(&backing_object->shadow_head); 580 KASSERT(object != NULL && 581 atomic_load_int(&backing_object->shadow_count) == 1, 582 ("vm_object_anon_deallocate: ref_count: %d, shadow_count: %d", 583 backing_object->ref_count, 584 atomic_load_int(&backing_object->shadow_count))); 585 KASSERT((object->flags & OBJ_ANON) != 0, 586 ("invalid shadow object %p", object)); 587 588 if (!VM_OBJECT_TRYWLOCK(object)) { 589 /* 590 * Prevent object from disappearing since we do not have a 591 * reference. 592 */ 593 vm_object_pip_add(object, 1); 594 VM_OBJECT_WUNLOCK(backing_object); 595 VM_OBJECT_WLOCK(object); 596 vm_object_pip_wakeup(object); 597 } else 598 VM_OBJECT_WUNLOCK(backing_object); 599 600 /* 601 * Check for a collapse/terminate race with the last reference holder. 602 */ 603 if ((object->flags & (OBJ_DEAD | OBJ_COLLAPSING)) != 0 || 604 !refcount_acquire_if_not_zero(&object->ref_count)) { 605 VM_OBJECT_WUNLOCK(object); 606 return (NULL); 607 } 608 backing_object = object->backing_object; 609 if (backing_object != NULL && (backing_object->flags & OBJ_ANON) != 0) 610 vm_object_collapse(object); 611 VM_OBJECT_WUNLOCK(object); 612 613 return (object); 614 } 615 616 /* 617 * vm_object_deallocate: 618 * 619 * Release a reference to the specified object, 620 * gained either through a vm_object_allocate 621 * or a vm_object_reference call. When all references 622 * are gone, storage associated with this object 623 * may be relinquished. 624 * 625 * No object may be locked. 626 */ 627 void 628 vm_object_deallocate(vm_object_t object) 629 { 630 vm_object_t temp; 631 bool released; 632 633 while (object != NULL) { 634 /* 635 * If the reference count goes to 0 we start calling 636 * vm_object_terminate() on the object chain. A ref count 637 * of 1 may be a special case depending on the shadow count 638 * being 0 or 1. These cases require a write lock on the 639 * object. 640 */ 641 if ((object->flags & OBJ_ANON) == 0) 642 released = refcount_release_if_gt(&object->ref_count, 1); 643 else 644 released = refcount_release_if_gt(&object->ref_count, 2); 645 if (released) 646 return; 647 648 if (object->type == OBJT_VNODE) { 649 VM_OBJECT_RLOCK(object); 650 if (object->type == OBJT_VNODE) { 651 vm_object_deallocate_vnode(object); 652 return; 653 } 654 VM_OBJECT_RUNLOCK(object); 655 } 656 657 VM_OBJECT_WLOCK(object); 658 KASSERT(object->ref_count > 0, 659 ("vm_object_deallocate: object deallocated too many times: %d", 660 object->type)); 661 662 /* 663 * If this is not the final reference to an anonymous 664 * object we may need to collapse the shadow chain. 665 */ 666 if (!refcount_release(&object->ref_count)) { 667 if (object->ref_count > 1 || 668 atomic_load_int(&object->shadow_count) == 0) { 669 if ((object->flags & OBJ_ANON) != 0 && 670 object->ref_count == 1) 671 vm_object_set_flag(object, 672 OBJ_ONEMAPPING); 673 VM_OBJECT_WUNLOCK(object); 674 return; 675 } 676 677 /* Handle collapsing last ref on anonymous objects. */ 678 object = vm_object_deallocate_anon(object); 679 continue; 680 } 681 682 /* 683 * Handle the final reference to an object. We restart 684 * the loop with the backing object to avoid recursion. 685 */ 686 umtx_shm_object_terminated(object); 687 temp = object->backing_object; 688 if (temp != NULL) { 689 KASSERT(object->type == OBJT_DEFAULT || 690 object->type == OBJT_SWAP, 691 ("shadowed tmpfs v_object 2 %p", object)); 692 vm_object_backing_remove(object); 693 } 694 695 KASSERT((object->flags & OBJ_DEAD) == 0, 696 ("vm_object_deallocate: Terminating dead object.")); 697 vm_object_set_flag(object, OBJ_DEAD); 698 vm_object_terminate(object); 699 object = temp; 700 } 701 } 702 703 /* 704 * vm_object_destroy removes the object from the global object list 705 * and frees the space for the object. 706 */ 707 void 708 vm_object_destroy(vm_object_t object) 709 { 710 711 /* 712 * Release the allocation charge. 713 */ 714 if (object->cred != NULL) { 715 swap_release_by_cred(object->charge, object->cred); 716 object->charge = 0; 717 crfree(object->cred); 718 object->cred = NULL; 719 } 720 721 /* 722 * Free the space for the object. 723 */ 724 uma_zfree(obj_zone, object); 725 } 726 727 static void 728 vm_object_sub_shadow(vm_object_t object) 729 { 730 KASSERT(object->shadow_count >= 1, 731 ("object %p sub_shadow count zero", object)); 732 atomic_subtract_int(&object->shadow_count, 1); 733 } 734 735 static void 736 vm_object_backing_remove_locked(vm_object_t object) 737 { 738 vm_object_t backing_object; 739 740 backing_object = object->backing_object; 741 VM_OBJECT_ASSERT_WLOCKED(object); 742 VM_OBJECT_ASSERT_WLOCKED(backing_object); 743 744 KASSERT((object->flags & OBJ_COLLAPSING) == 0, 745 ("vm_object_backing_remove: Removing collapsing object.")); 746 747 vm_object_sub_shadow(backing_object); 748 if ((object->flags & OBJ_SHADOWLIST) != 0) { 749 LIST_REMOVE(object, shadow_list); 750 vm_object_clear_flag(object, OBJ_SHADOWLIST); 751 } 752 object->backing_object = NULL; 753 } 754 755 static void 756 vm_object_backing_remove(vm_object_t object) 757 { 758 vm_object_t backing_object; 759 760 VM_OBJECT_ASSERT_WLOCKED(object); 761 762 backing_object = object->backing_object; 763 if ((object->flags & OBJ_SHADOWLIST) != 0) { 764 VM_OBJECT_WLOCK(backing_object); 765 vm_object_backing_remove_locked(object); 766 VM_OBJECT_WUNLOCK(backing_object); 767 } else { 768 object->backing_object = NULL; 769 vm_object_sub_shadow(backing_object); 770 } 771 } 772 773 static void 774 vm_object_backing_insert_locked(vm_object_t object, vm_object_t backing_object) 775 { 776 777 VM_OBJECT_ASSERT_WLOCKED(object); 778 779 atomic_add_int(&backing_object->shadow_count, 1); 780 if ((backing_object->flags & OBJ_ANON) != 0) { 781 VM_OBJECT_ASSERT_WLOCKED(backing_object); 782 LIST_INSERT_HEAD(&backing_object->shadow_head, object, 783 shadow_list); 784 vm_object_set_flag(object, OBJ_SHADOWLIST); 785 } 786 object->backing_object = backing_object; 787 } 788 789 static void 790 vm_object_backing_insert(vm_object_t object, vm_object_t backing_object) 791 { 792 793 VM_OBJECT_ASSERT_WLOCKED(object); 794 795 if ((backing_object->flags & OBJ_ANON) != 0) { 796 VM_OBJECT_WLOCK(backing_object); 797 vm_object_backing_insert_locked(object, backing_object); 798 VM_OBJECT_WUNLOCK(backing_object); 799 } else { 800 object->backing_object = backing_object; 801 atomic_add_int(&backing_object->shadow_count, 1); 802 } 803 } 804 805 /* 806 * Insert an object into a backing_object's shadow list with an additional 807 * reference to the backing_object added. 808 */ 809 static void 810 vm_object_backing_insert_ref(vm_object_t object, vm_object_t backing_object) 811 { 812 813 VM_OBJECT_ASSERT_WLOCKED(object); 814 815 if ((backing_object->flags & OBJ_ANON) != 0) { 816 VM_OBJECT_WLOCK(backing_object); 817 KASSERT((backing_object->flags & OBJ_DEAD) == 0, 818 ("shadowing dead anonymous object")); 819 vm_object_reference_locked(backing_object); 820 vm_object_backing_insert_locked(object, backing_object); 821 vm_object_clear_flag(backing_object, OBJ_ONEMAPPING); 822 VM_OBJECT_WUNLOCK(backing_object); 823 } else { 824 vm_object_reference(backing_object); 825 atomic_add_int(&backing_object->shadow_count, 1); 826 object->backing_object = backing_object; 827 } 828 } 829 830 /* 831 * Transfer a backing reference from backing_object to object. 832 */ 833 static void 834 vm_object_backing_transfer(vm_object_t object, vm_object_t backing_object) 835 { 836 vm_object_t new_backing_object; 837 838 /* 839 * Note that the reference to backing_object->backing_object 840 * moves from within backing_object to within object. 841 */ 842 vm_object_backing_remove_locked(object); 843 new_backing_object = backing_object->backing_object; 844 if (new_backing_object == NULL) 845 return; 846 if ((new_backing_object->flags & OBJ_ANON) != 0) { 847 VM_OBJECT_WLOCK(new_backing_object); 848 vm_object_backing_remove_locked(backing_object); 849 vm_object_backing_insert_locked(object, new_backing_object); 850 VM_OBJECT_WUNLOCK(new_backing_object); 851 } else { 852 /* 853 * shadow_count for new_backing_object is left 854 * unchanged, its reference provided by backing_object 855 * is replaced by object. 856 */ 857 object->backing_object = new_backing_object; 858 backing_object->backing_object = NULL; 859 } 860 } 861 862 /* 863 * Wait for a concurrent collapse to settle. 864 */ 865 static void 866 vm_object_collapse_wait(vm_object_t object) 867 { 868 869 VM_OBJECT_ASSERT_WLOCKED(object); 870 871 while ((object->flags & OBJ_COLLAPSING) != 0) { 872 vm_object_pip_wait(object, "vmcolwait"); 873 counter_u64_add(object_collapse_waits, 1); 874 } 875 } 876 877 /* 878 * Waits for a backing object to clear a pending collapse and returns 879 * it locked if it is an ANON object. 880 */ 881 static vm_object_t 882 vm_object_backing_collapse_wait(vm_object_t object) 883 { 884 vm_object_t backing_object; 885 886 VM_OBJECT_ASSERT_WLOCKED(object); 887 888 for (;;) { 889 backing_object = object->backing_object; 890 if (backing_object == NULL || 891 (backing_object->flags & OBJ_ANON) == 0) 892 return (NULL); 893 VM_OBJECT_WLOCK(backing_object); 894 if ((backing_object->flags & (OBJ_DEAD | OBJ_COLLAPSING)) == 0) 895 break; 896 VM_OBJECT_WUNLOCK(object); 897 vm_object_pip_sleep(backing_object, "vmbckwait"); 898 counter_u64_add(object_collapse_waits, 1); 899 VM_OBJECT_WLOCK(object); 900 } 901 return (backing_object); 902 } 903 904 /* 905 * vm_object_terminate_pages removes any remaining pageable pages 906 * from the object and resets the object to an empty state. 907 */ 908 static void 909 vm_object_terminate_pages(vm_object_t object) 910 { 911 vm_page_t p, p_next; 912 913 VM_OBJECT_ASSERT_WLOCKED(object); 914 915 /* 916 * Free any remaining pageable pages. This also removes them from the 917 * paging queues. However, don't free wired pages, just remove them 918 * from the object. Rather than incrementally removing each page from 919 * the object, the page and object are reset to any empty state. 920 */ 921 TAILQ_FOREACH_SAFE(p, &object->memq, listq, p_next) { 922 vm_page_assert_unbusied(p); 923 KASSERT(p->object == object && 924 (p->ref_count & VPRC_OBJREF) != 0, 925 ("vm_object_terminate_pages: page %p is inconsistent", p)); 926 927 p->object = NULL; 928 if (vm_page_drop(p, VPRC_OBJREF) == VPRC_OBJREF) { 929 VM_CNT_INC(v_pfree); 930 vm_page_free(p); 931 } 932 } 933 934 /* 935 * If the object contained any pages, then reset it to an empty state. 936 * None of the object's fields, including "resident_page_count", were 937 * modified by the preceding loop. 938 */ 939 if (object->resident_page_count != 0) { 940 vm_radix_reclaim_allnodes(&object->rtree); 941 TAILQ_INIT(&object->memq); 942 object->resident_page_count = 0; 943 if (object->type == OBJT_VNODE) 944 vdrop(object->handle); 945 } 946 } 947 948 /* 949 * vm_object_terminate actually destroys the specified object, freeing 950 * up all previously used resources. 951 * 952 * The object must be locked. 953 * This routine may block. 954 */ 955 void 956 vm_object_terminate(vm_object_t object) 957 { 958 959 VM_OBJECT_ASSERT_WLOCKED(object); 960 KASSERT((object->flags & OBJ_DEAD) != 0, 961 ("terminating non-dead obj %p", object)); 962 KASSERT((object->flags & OBJ_COLLAPSING) == 0, 963 ("terminating collapsing obj %p", object)); 964 KASSERT(object->backing_object == NULL, 965 ("terminating shadow obj %p", object)); 966 967 /* 968 * Wait for the pageout daemon and other current users to be 969 * done with the object. Note that new paging_in_progress 970 * users can come after this wait, but they must check 971 * OBJ_DEAD flag set (without unlocking the object), and avoid 972 * the object being terminated. 973 */ 974 vm_object_pip_wait(object, "objtrm"); 975 976 KASSERT(object->ref_count == 0, 977 ("vm_object_terminate: object with references, ref_count=%d", 978 object->ref_count)); 979 980 if ((object->flags & OBJ_PG_DTOR) == 0) 981 vm_object_terminate_pages(object); 982 983 #if VM_NRESERVLEVEL > 0 984 if (__predict_false(!LIST_EMPTY(&object->rvq))) 985 vm_reserv_break_all(object); 986 #endif 987 988 KASSERT(object->cred == NULL || object->type == OBJT_DEFAULT || 989 (object->flags & OBJ_SWAP) != 0, 990 ("%s: non-swap obj %p has cred", __func__, object)); 991 992 /* 993 * Let the pager know object is dead. 994 */ 995 vm_pager_deallocate(object); 996 VM_OBJECT_WUNLOCK(object); 997 998 vm_object_destroy(object); 999 } 1000 1001 /* 1002 * Make the page read-only so that we can clear the object flags. However, if 1003 * this is a nosync mmap then the object is likely to stay dirty so do not 1004 * mess with the page and do not clear the object flags. Returns TRUE if the 1005 * page should be flushed, and FALSE otherwise. 1006 */ 1007 static boolean_t 1008 vm_object_page_remove_write(vm_page_t p, int flags, boolean_t *allclean) 1009 { 1010 1011 vm_page_assert_busied(p); 1012 1013 /* 1014 * If we have been asked to skip nosync pages and this is a 1015 * nosync page, skip it. Note that the object flags were not 1016 * cleared in this case so we do not have to set them. 1017 */ 1018 if ((flags & OBJPC_NOSYNC) != 0 && (p->a.flags & PGA_NOSYNC) != 0) { 1019 *allclean = FALSE; 1020 return (FALSE); 1021 } else { 1022 pmap_remove_write(p); 1023 return (p->dirty != 0); 1024 } 1025 } 1026 1027 /* 1028 * vm_object_page_clean 1029 * 1030 * Clean all dirty pages in the specified range of object. Leaves page 1031 * on whatever queue it is currently on. If NOSYNC is set then do not 1032 * write out pages with PGA_NOSYNC set (originally comes from MAP_NOSYNC), 1033 * leaving the object dirty. 1034 * 1035 * For swap objects backing tmpfs regular files, do not flush anything, 1036 * but remove write protection on the mapped pages to update mtime through 1037 * mmaped writes. 1038 * 1039 * When stuffing pages asynchronously, allow clustering. XXX we need a 1040 * synchronous clustering mode implementation. 1041 * 1042 * Odd semantics: if start == end, we clean everything. 1043 * 1044 * The object must be locked. 1045 * 1046 * Returns FALSE if some page from the range was not written, as 1047 * reported by the pager, and TRUE otherwise. 1048 */ 1049 boolean_t 1050 vm_object_page_clean(vm_object_t object, vm_ooffset_t start, vm_ooffset_t end, 1051 int flags) 1052 { 1053 vm_page_t np, p; 1054 vm_pindex_t pi, tend, tstart; 1055 int curgeneration, n, pagerflags; 1056 boolean_t eio, res, allclean; 1057 1058 VM_OBJECT_ASSERT_WLOCKED(object); 1059 1060 if (!vm_object_mightbedirty(object) || object->resident_page_count == 0) 1061 return (TRUE); 1062 1063 pagerflags = (flags & (OBJPC_SYNC | OBJPC_INVAL)) != 0 ? 1064 VM_PAGER_PUT_SYNC : VM_PAGER_CLUSTER_OK; 1065 pagerflags |= (flags & OBJPC_INVAL) != 0 ? VM_PAGER_PUT_INVAL : 0; 1066 1067 tstart = OFF_TO_IDX(start); 1068 tend = (end == 0) ? object->size : OFF_TO_IDX(end + PAGE_MASK); 1069 allclean = tstart == 0 && tend >= object->size; 1070 res = TRUE; 1071 1072 rescan: 1073 curgeneration = object->generation; 1074 1075 for (p = vm_page_find_least(object, tstart); p != NULL; p = np) { 1076 pi = p->pindex; 1077 if (pi >= tend) 1078 break; 1079 np = TAILQ_NEXT(p, listq); 1080 if (vm_page_none_valid(p)) 1081 continue; 1082 if (vm_page_busy_acquire(p, VM_ALLOC_WAITFAIL) == 0) { 1083 if (object->generation != curgeneration && 1084 (flags & OBJPC_SYNC) != 0) 1085 goto rescan; 1086 np = vm_page_find_least(object, pi); 1087 continue; 1088 } 1089 if (!vm_object_page_remove_write(p, flags, &allclean)) { 1090 vm_page_xunbusy(p); 1091 continue; 1092 } 1093 if (object->type == OBJT_VNODE) { 1094 n = vm_object_page_collect_flush(object, p, pagerflags, 1095 flags, &allclean, &eio); 1096 if (eio) { 1097 res = FALSE; 1098 allclean = FALSE; 1099 } 1100 if (object->generation != curgeneration && 1101 (flags & OBJPC_SYNC) != 0) 1102 goto rescan; 1103 1104 /* 1105 * If the VOP_PUTPAGES() did a truncated write, so 1106 * that even the first page of the run is not fully 1107 * written, vm_pageout_flush() returns 0 as the run 1108 * length. Since the condition that caused truncated 1109 * write may be permanent, e.g. exhausted free space, 1110 * accepting n == 0 would cause an infinite loop. 1111 * 1112 * Forwarding the iterator leaves the unwritten page 1113 * behind, but there is not much we can do there if 1114 * filesystem refuses to write it. 1115 */ 1116 if (n == 0) { 1117 n = 1; 1118 allclean = FALSE; 1119 } 1120 } else { 1121 n = 1; 1122 vm_page_xunbusy(p); 1123 } 1124 np = vm_page_find_least(object, pi + n); 1125 } 1126 #if 0 1127 VOP_FSYNC(vp, (pagerflags & VM_PAGER_PUT_SYNC) ? MNT_WAIT : 0); 1128 #endif 1129 1130 /* 1131 * Leave updating cleangeneration for tmpfs objects to tmpfs 1132 * scan. It needs to update mtime, which happens for other 1133 * filesystems during page writeouts. 1134 */ 1135 if (allclean && object->type == OBJT_VNODE) 1136 object->cleangeneration = curgeneration; 1137 return (res); 1138 } 1139 1140 static int 1141 vm_object_page_collect_flush(vm_object_t object, vm_page_t p, int pagerflags, 1142 int flags, boolean_t *allclean, boolean_t *eio) 1143 { 1144 vm_page_t ma[vm_pageout_page_count], p_first, tp; 1145 int count, i, mreq, runlen; 1146 1147 vm_page_lock_assert(p, MA_NOTOWNED); 1148 vm_page_assert_xbusied(p); 1149 VM_OBJECT_ASSERT_WLOCKED(object); 1150 1151 count = 1; 1152 mreq = 0; 1153 1154 for (tp = p; count < vm_pageout_page_count; count++) { 1155 tp = vm_page_next(tp); 1156 if (tp == NULL || vm_page_tryxbusy(tp) == 0) 1157 break; 1158 if (!vm_object_page_remove_write(tp, flags, allclean)) { 1159 vm_page_xunbusy(tp); 1160 break; 1161 } 1162 } 1163 1164 for (p_first = p; count < vm_pageout_page_count; count++) { 1165 tp = vm_page_prev(p_first); 1166 if (tp == NULL || vm_page_tryxbusy(tp) == 0) 1167 break; 1168 if (!vm_object_page_remove_write(tp, flags, allclean)) { 1169 vm_page_xunbusy(tp); 1170 break; 1171 } 1172 p_first = tp; 1173 mreq++; 1174 } 1175 1176 for (tp = p_first, i = 0; i < count; tp = TAILQ_NEXT(tp, listq), i++) 1177 ma[i] = tp; 1178 1179 vm_pageout_flush(ma, count, pagerflags, mreq, &runlen, eio); 1180 return (runlen); 1181 } 1182 1183 /* 1184 * Note that there is absolutely no sense in writing out 1185 * anonymous objects, so we track down the vnode object 1186 * to write out. 1187 * We invalidate (remove) all pages from the address space 1188 * for semantic correctness. 1189 * 1190 * If the backing object is a device object with unmanaged pages, then any 1191 * mappings to the specified range of pages must be removed before this 1192 * function is called. 1193 * 1194 * Note: certain anonymous maps, such as MAP_NOSYNC maps, 1195 * may start out with a NULL object. 1196 */ 1197 boolean_t 1198 vm_object_sync(vm_object_t object, vm_ooffset_t offset, vm_size_t size, 1199 boolean_t syncio, boolean_t invalidate) 1200 { 1201 vm_object_t backing_object; 1202 struct vnode *vp; 1203 struct mount *mp; 1204 int error, flags, fsync_after; 1205 boolean_t res; 1206 1207 if (object == NULL) 1208 return (TRUE); 1209 res = TRUE; 1210 error = 0; 1211 VM_OBJECT_WLOCK(object); 1212 while ((backing_object = object->backing_object) != NULL) { 1213 VM_OBJECT_WLOCK(backing_object); 1214 offset += object->backing_object_offset; 1215 VM_OBJECT_WUNLOCK(object); 1216 object = backing_object; 1217 if (object->size < OFF_TO_IDX(offset + size)) 1218 size = IDX_TO_OFF(object->size) - offset; 1219 } 1220 /* 1221 * Flush pages if writing is allowed, invalidate them 1222 * if invalidation requested. Pages undergoing I/O 1223 * will be ignored by vm_object_page_remove(). 1224 * 1225 * We cannot lock the vnode and then wait for paging 1226 * to complete without deadlocking against vm_fault. 1227 * Instead we simply call vm_object_page_remove() and 1228 * allow it to block internally on a page-by-page 1229 * basis when it encounters pages undergoing async 1230 * I/O. 1231 */ 1232 if (object->type == OBJT_VNODE && 1233 vm_object_mightbedirty(object) != 0 && 1234 ((vp = object->handle)->v_vflag & VV_NOSYNC) == 0) { 1235 VM_OBJECT_WUNLOCK(object); 1236 (void) vn_start_write(vp, &mp, V_WAIT); 1237 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY); 1238 if (syncio && !invalidate && offset == 0 && 1239 atop(size) == object->size) { 1240 /* 1241 * If syncing the whole mapping of the file, 1242 * it is faster to schedule all the writes in 1243 * async mode, also allowing the clustering, 1244 * and then wait for i/o to complete. 1245 */ 1246 flags = 0; 1247 fsync_after = TRUE; 1248 } else { 1249 flags = (syncio || invalidate) ? OBJPC_SYNC : 0; 1250 flags |= invalidate ? (OBJPC_SYNC | OBJPC_INVAL) : 0; 1251 fsync_after = FALSE; 1252 } 1253 VM_OBJECT_WLOCK(object); 1254 res = vm_object_page_clean(object, offset, offset + size, 1255 flags); 1256 VM_OBJECT_WUNLOCK(object); 1257 if (fsync_after) 1258 error = VOP_FSYNC(vp, MNT_WAIT, curthread); 1259 VOP_UNLOCK(vp); 1260 vn_finished_write(mp); 1261 if (error != 0) 1262 res = FALSE; 1263 VM_OBJECT_WLOCK(object); 1264 } 1265 if ((object->type == OBJT_VNODE || 1266 object->type == OBJT_DEVICE) && invalidate) { 1267 if (object->type == OBJT_DEVICE) 1268 /* 1269 * The option OBJPR_NOTMAPPED must be passed here 1270 * because vm_object_page_remove() cannot remove 1271 * unmanaged mappings. 1272 */ 1273 flags = OBJPR_NOTMAPPED; 1274 else if (old_msync) 1275 flags = 0; 1276 else 1277 flags = OBJPR_CLEANONLY; 1278 vm_object_page_remove(object, OFF_TO_IDX(offset), 1279 OFF_TO_IDX(offset + size + PAGE_MASK), flags); 1280 } 1281 VM_OBJECT_WUNLOCK(object); 1282 return (res); 1283 } 1284 1285 /* 1286 * Determine whether the given advice can be applied to the object. Advice is 1287 * not applied to unmanaged pages since they never belong to page queues, and 1288 * since MADV_FREE is destructive, it can apply only to anonymous pages that 1289 * have been mapped at most once. 1290 */ 1291 static bool 1292 vm_object_advice_applies(vm_object_t object, int advice) 1293 { 1294 1295 if ((object->flags & OBJ_UNMANAGED) != 0) 1296 return (false); 1297 if (advice != MADV_FREE) 1298 return (true); 1299 return ((object->flags & (OBJ_ONEMAPPING | OBJ_ANON)) == 1300 (OBJ_ONEMAPPING | OBJ_ANON)); 1301 } 1302 1303 static void 1304 vm_object_madvise_freespace(vm_object_t object, int advice, vm_pindex_t pindex, 1305 vm_size_t size) 1306 { 1307 1308 if (advice == MADV_FREE) 1309 vm_pager_freespace(object, pindex, size); 1310 } 1311 1312 /* 1313 * vm_object_madvise: 1314 * 1315 * Implements the madvise function at the object/page level. 1316 * 1317 * MADV_WILLNEED (any object) 1318 * 1319 * Activate the specified pages if they are resident. 1320 * 1321 * MADV_DONTNEED (any object) 1322 * 1323 * Deactivate the specified pages if they are resident. 1324 * 1325 * MADV_FREE (OBJT_DEFAULT/OBJT_SWAP objects, 1326 * OBJ_ONEMAPPING only) 1327 * 1328 * Deactivate and clean the specified pages if they are 1329 * resident. This permits the process to reuse the pages 1330 * without faulting or the kernel to reclaim the pages 1331 * without I/O. 1332 */ 1333 void 1334 vm_object_madvise(vm_object_t object, vm_pindex_t pindex, vm_pindex_t end, 1335 int advice) 1336 { 1337 vm_pindex_t tpindex; 1338 vm_object_t backing_object, tobject; 1339 vm_page_t m, tm; 1340 1341 if (object == NULL) 1342 return; 1343 1344 relookup: 1345 VM_OBJECT_WLOCK(object); 1346 if (!vm_object_advice_applies(object, advice)) { 1347 VM_OBJECT_WUNLOCK(object); 1348 return; 1349 } 1350 for (m = vm_page_find_least(object, pindex); pindex < end; pindex++) { 1351 tobject = object; 1352 1353 /* 1354 * If the next page isn't resident in the top-level object, we 1355 * need to search the shadow chain. When applying MADV_FREE, we 1356 * take care to release any swap space used to store 1357 * non-resident pages. 1358 */ 1359 if (m == NULL || pindex < m->pindex) { 1360 /* 1361 * Optimize a common case: if the top-level object has 1362 * no backing object, we can skip over the non-resident 1363 * range in constant time. 1364 */ 1365 if (object->backing_object == NULL) { 1366 tpindex = (m != NULL && m->pindex < end) ? 1367 m->pindex : end; 1368 vm_object_madvise_freespace(object, advice, 1369 pindex, tpindex - pindex); 1370 if ((pindex = tpindex) == end) 1371 break; 1372 goto next_page; 1373 } 1374 1375 tpindex = pindex; 1376 do { 1377 vm_object_madvise_freespace(tobject, advice, 1378 tpindex, 1); 1379 /* 1380 * Prepare to search the next object in the 1381 * chain. 1382 */ 1383 backing_object = tobject->backing_object; 1384 if (backing_object == NULL) 1385 goto next_pindex; 1386 VM_OBJECT_WLOCK(backing_object); 1387 tpindex += 1388 OFF_TO_IDX(tobject->backing_object_offset); 1389 if (tobject != object) 1390 VM_OBJECT_WUNLOCK(tobject); 1391 tobject = backing_object; 1392 if (!vm_object_advice_applies(tobject, advice)) 1393 goto next_pindex; 1394 } while ((tm = vm_page_lookup(tobject, tpindex)) == 1395 NULL); 1396 } else { 1397 next_page: 1398 tm = m; 1399 m = TAILQ_NEXT(m, listq); 1400 } 1401 1402 /* 1403 * If the page is not in a normal state, skip it. The page 1404 * can not be invalidated while the object lock is held. 1405 */ 1406 if (!vm_page_all_valid(tm) || vm_page_wired(tm)) 1407 goto next_pindex; 1408 KASSERT((tm->flags & PG_FICTITIOUS) == 0, 1409 ("vm_object_madvise: page %p is fictitious", tm)); 1410 KASSERT((tm->oflags & VPO_UNMANAGED) == 0, 1411 ("vm_object_madvise: page %p is not managed", tm)); 1412 if (vm_page_tryxbusy(tm) == 0) { 1413 if (object != tobject) 1414 VM_OBJECT_WUNLOCK(object); 1415 if (advice == MADV_WILLNEED) { 1416 /* 1417 * Reference the page before unlocking and 1418 * sleeping so that the page daemon is less 1419 * likely to reclaim it. 1420 */ 1421 vm_page_aflag_set(tm, PGA_REFERENCED); 1422 } 1423 if (!vm_page_busy_sleep(tm, "madvpo", 0)) 1424 VM_OBJECT_WUNLOCK(tobject); 1425 goto relookup; 1426 } 1427 vm_page_advise(tm, advice); 1428 vm_page_xunbusy(tm); 1429 vm_object_madvise_freespace(tobject, advice, tm->pindex, 1); 1430 next_pindex: 1431 if (tobject != object) 1432 VM_OBJECT_WUNLOCK(tobject); 1433 } 1434 VM_OBJECT_WUNLOCK(object); 1435 } 1436 1437 /* 1438 * vm_object_shadow: 1439 * 1440 * Create a new object which is backed by the 1441 * specified existing object range. The source 1442 * object reference is deallocated. 1443 * 1444 * The new object and offset into that object 1445 * are returned in the source parameters. 1446 */ 1447 void 1448 vm_object_shadow(vm_object_t *object, vm_ooffset_t *offset, vm_size_t length, 1449 struct ucred *cred, bool shared) 1450 { 1451 vm_object_t source; 1452 vm_object_t result; 1453 1454 source = *object; 1455 1456 /* 1457 * Don't create the new object if the old object isn't shared. 1458 * 1459 * If we hold the only reference we can guarantee that it won't 1460 * increase while we have the map locked. Otherwise the race is 1461 * harmless and we will end up with an extra shadow object that 1462 * will be collapsed later. 1463 */ 1464 if (source != NULL && source->ref_count == 1 && 1465 (source->flags & OBJ_ANON) != 0) 1466 return; 1467 1468 /* 1469 * Allocate a new object with the given length. 1470 */ 1471 result = vm_object_allocate_anon(atop(length), source, cred, length); 1472 1473 /* 1474 * Store the offset into the source object, and fix up the offset into 1475 * the new object. 1476 */ 1477 result->backing_object_offset = *offset; 1478 1479 if (shared || source != NULL) { 1480 VM_OBJECT_WLOCK(result); 1481 1482 /* 1483 * The new object shadows the source object, adding a 1484 * reference to it. Our caller changes his reference 1485 * to point to the new object, removing a reference to 1486 * the source object. Net result: no change of 1487 * reference count, unless the caller needs to add one 1488 * more reference due to forking a shared map entry. 1489 */ 1490 if (shared) { 1491 vm_object_reference_locked(result); 1492 vm_object_clear_flag(result, OBJ_ONEMAPPING); 1493 } 1494 1495 /* 1496 * Try to optimize the result object's page color when 1497 * shadowing in order to maintain page coloring 1498 * consistency in the combined shadowed object. 1499 */ 1500 if (source != NULL) { 1501 vm_object_backing_insert(result, source); 1502 result->domain = source->domain; 1503 #if VM_NRESERVLEVEL > 0 1504 vm_object_set_flag(result, 1505 (source->flags & OBJ_COLORED)); 1506 result->pg_color = (source->pg_color + 1507 OFF_TO_IDX(*offset)) & ((1 << (VM_NFREEORDER - 1508 1)) - 1); 1509 #endif 1510 } 1511 VM_OBJECT_WUNLOCK(result); 1512 } 1513 1514 /* 1515 * Return the new things 1516 */ 1517 *offset = 0; 1518 *object = result; 1519 } 1520 1521 /* 1522 * vm_object_split: 1523 * 1524 * Split the pages in a map entry into a new object. This affords 1525 * easier removal of unused pages, and keeps object inheritance from 1526 * being a negative impact on memory usage. 1527 */ 1528 void 1529 vm_object_split(vm_map_entry_t entry) 1530 { 1531 vm_page_t m, m_busy, m_next; 1532 vm_object_t orig_object, new_object, backing_object; 1533 vm_pindex_t idx, offidxstart; 1534 vm_size_t size; 1535 1536 orig_object = entry->object.vm_object; 1537 KASSERT((orig_object->flags & OBJ_ONEMAPPING) != 0, 1538 ("vm_object_split: Splitting object with multiple mappings.")); 1539 if ((orig_object->flags & OBJ_ANON) == 0) 1540 return; 1541 if (orig_object->ref_count <= 1) 1542 return; 1543 VM_OBJECT_WUNLOCK(orig_object); 1544 1545 offidxstart = OFF_TO_IDX(entry->offset); 1546 size = atop(entry->end - entry->start); 1547 1548 /* 1549 * If swap_pager_copy() is later called, it will convert new_object 1550 * into a swap object. 1551 */ 1552 new_object = vm_object_allocate_anon(size, orig_object, 1553 orig_object->cred, ptoa(size)); 1554 1555 /* 1556 * We must wait for the orig_object to complete any in-progress 1557 * collapse so that the swap blocks are stable below. The 1558 * additional reference on backing_object by new object will 1559 * prevent further collapse operations until split completes. 1560 */ 1561 VM_OBJECT_WLOCK(orig_object); 1562 vm_object_collapse_wait(orig_object); 1563 1564 /* 1565 * At this point, the new object is still private, so the order in 1566 * which the original and new objects are locked does not matter. 1567 */ 1568 VM_OBJECT_WLOCK(new_object); 1569 new_object->domain = orig_object->domain; 1570 backing_object = orig_object->backing_object; 1571 if (backing_object != NULL) { 1572 vm_object_backing_insert_ref(new_object, backing_object); 1573 new_object->backing_object_offset = 1574 orig_object->backing_object_offset + entry->offset; 1575 } 1576 if (orig_object->cred != NULL) { 1577 crhold(orig_object->cred); 1578 KASSERT(orig_object->charge >= ptoa(size), 1579 ("orig_object->charge < 0")); 1580 orig_object->charge -= ptoa(size); 1581 } 1582 1583 /* 1584 * Mark the split operation so that swap_pager_getpages() knows 1585 * that the object is in transition. 1586 */ 1587 vm_object_set_flag(orig_object, OBJ_SPLIT); 1588 m_busy = NULL; 1589 #ifdef INVARIANTS 1590 idx = 0; 1591 #endif 1592 retry: 1593 m = vm_page_find_least(orig_object, offidxstart); 1594 KASSERT(m == NULL || idx <= m->pindex - offidxstart, 1595 ("%s: object %p was repopulated", __func__, orig_object)); 1596 for (; m != NULL && (idx = m->pindex - offidxstart) < size; 1597 m = m_next) { 1598 m_next = TAILQ_NEXT(m, listq); 1599 1600 /* 1601 * We must wait for pending I/O to complete before we can 1602 * rename the page. 1603 * 1604 * We do not have to VM_PROT_NONE the page as mappings should 1605 * not be changed by this operation. 1606 */ 1607 if (vm_page_tryxbusy(m) == 0) { 1608 VM_OBJECT_WUNLOCK(new_object); 1609 if (vm_page_busy_sleep(m, "spltwt", 0)) 1610 VM_OBJECT_WLOCK(orig_object); 1611 VM_OBJECT_WLOCK(new_object); 1612 goto retry; 1613 } 1614 1615 /* 1616 * The page was left invalid. Likely placed there by 1617 * an incomplete fault. Just remove and ignore. 1618 */ 1619 if (vm_page_none_valid(m)) { 1620 if (vm_page_remove(m)) 1621 vm_page_free(m); 1622 continue; 1623 } 1624 1625 /* vm_page_rename() will dirty the page. */ 1626 if (vm_page_rename(m, new_object, idx)) { 1627 vm_page_xunbusy(m); 1628 VM_OBJECT_WUNLOCK(new_object); 1629 VM_OBJECT_WUNLOCK(orig_object); 1630 vm_radix_wait(); 1631 VM_OBJECT_WLOCK(orig_object); 1632 VM_OBJECT_WLOCK(new_object); 1633 goto retry; 1634 } 1635 1636 #if VM_NRESERVLEVEL > 0 1637 /* 1638 * If some of the reservation's allocated pages remain with 1639 * the original object, then transferring the reservation to 1640 * the new object is neither particularly beneficial nor 1641 * particularly harmful as compared to leaving the reservation 1642 * with the original object. If, however, all of the 1643 * reservation's allocated pages are transferred to the new 1644 * object, then transferring the reservation is typically 1645 * beneficial. Determining which of these two cases applies 1646 * would be more costly than unconditionally renaming the 1647 * reservation. 1648 */ 1649 vm_reserv_rename(m, new_object, orig_object, offidxstart); 1650 #endif 1651 1652 /* 1653 * orig_object's type may change while sleeping, so keep track 1654 * of the beginning of the busied range. 1655 */ 1656 if (orig_object->type != OBJT_SWAP) 1657 vm_page_xunbusy(m); 1658 else if (m_busy == NULL) 1659 m_busy = m; 1660 } 1661 if ((orig_object->flags & OBJ_SWAP) != 0) { 1662 /* 1663 * swap_pager_copy() can sleep, in which case the orig_object's 1664 * and new_object's locks are released and reacquired. 1665 */ 1666 swap_pager_copy(orig_object, new_object, offidxstart, 0); 1667 if (m_busy != NULL) 1668 TAILQ_FOREACH_FROM(m_busy, &new_object->memq, listq) 1669 vm_page_xunbusy(m_busy); 1670 } 1671 vm_object_clear_flag(orig_object, OBJ_SPLIT); 1672 VM_OBJECT_WUNLOCK(orig_object); 1673 VM_OBJECT_WUNLOCK(new_object); 1674 entry->object.vm_object = new_object; 1675 entry->offset = 0LL; 1676 vm_object_deallocate(orig_object); 1677 VM_OBJECT_WLOCK(new_object); 1678 } 1679 1680 static vm_page_t 1681 vm_object_collapse_scan_wait(vm_object_t object, vm_page_t p) 1682 { 1683 vm_object_t backing_object; 1684 1685 VM_OBJECT_ASSERT_WLOCKED(object); 1686 backing_object = object->backing_object; 1687 VM_OBJECT_ASSERT_WLOCKED(backing_object); 1688 1689 KASSERT(p == NULL || p->object == object || p->object == backing_object, 1690 ("invalid ownership %p %p %p", p, object, backing_object)); 1691 /* The page is only NULL when rename fails. */ 1692 if (p == NULL) { 1693 VM_OBJECT_WUNLOCK(object); 1694 VM_OBJECT_WUNLOCK(backing_object); 1695 vm_radix_wait(); 1696 VM_OBJECT_WLOCK(object); 1697 } else if (p->object == object) { 1698 VM_OBJECT_WUNLOCK(backing_object); 1699 if (vm_page_busy_sleep(p, "vmocol", 0)) 1700 VM_OBJECT_WLOCK(object); 1701 } else { 1702 VM_OBJECT_WUNLOCK(object); 1703 if (!vm_page_busy_sleep(p, "vmocol", 0)) 1704 VM_OBJECT_WUNLOCK(backing_object); 1705 VM_OBJECT_WLOCK(object); 1706 } 1707 VM_OBJECT_WLOCK(backing_object); 1708 return (TAILQ_FIRST(&backing_object->memq)); 1709 } 1710 1711 static bool 1712 vm_object_scan_all_shadowed(vm_object_t object) 1713 { 1714 vm_object_t backing_object; 1715 vm_page_t p, pp; 1716 vm_pindex_t backing_offset_index, new_pindex, pi, ps; 1717 1718 VM_OBJECT_ASSERT_WLOCKED(object); 1719 VM_OBJECT_ASSERT_WLOCKED(object->backing_object); 1720 1721 backing_object = object->backing_object; 1722 1723 if ((backing_object->flags & OBJ_ANON) == 0) 1724 return (false); 1725 1726 pi = backing_offset_index = OFF_TO_IDX(object->backing_object_offset); 1727 p = vm_page_find_least(backing_object, pi); 1728 ps = swap_pager_find_least(backing_object, pi); 1729 1730 /* 1731 * Only check pages inside the parent object's range and 1732 * inside the parent object's mapping of the backing object. 1733 */ 1734 for (;; pi++) { 1735 if (p != NULL && p->pindex < pi) 1736 p = TAILQ_NEXT(p, listq); 1737 if (ps < pi) 1738 ps = swap_pager_find_least(backing_object, pi); 1739 if (p == NULL && ps >= backing_object->size) 1740 break; 1741 else if (p == NULL) 1742 pi = ps; 1743 else 1744 pi = MIN(p->pindex, ps); 1745 1746 new_pindex = pi - backing_offset_index; 1747 if (new_pindex >= object->size) 1748 break; 1749 1750 if (p != NULL) { 1751 /* 1752 * If the backing object page is busy a 1753 * grandparent or older page may still be 1754 * undergoing CoW. It is not safe to collapse 1755 * the backing object until it is quiesced. 1756 */ 1757 if (vm_page_tryxbusy(p) == 0) 1758 return (false); 1759 1760 /* 1761 * We raced with the fault handler that left 1762 * newly allocated invalid page on the object 1763 * queue and retried. 1764 */ 1765 if (!vm_page_all_valid(p)) 1766 goto unbusy_ret; 1767 } 1768 1769 /* 1770 * See if the parent has the page or if the parent's object 1771 * pager has the page. If the parent has the page but the page 1772 * is not valid, the parent's object pager must have the page. 1773 * 1774 * If this fails, the parent does not completely shadow the 1775 * object and we might as well give up now. 1776 */ 1777 pp = vm_page_lookup(object, new_pindex); 1778 1779 /* 1780 * The valid check here is stable due to object lock 1781 * being required to clear valid and initiate paging. 1782 * Busy of p disallows fault handler to validate pp. 1783 */ 1784 if ((pp == NULL || vm_page_none_valid(pp)) && 1785 !vm_pager_has_page(object, new_pindex, NULL, NULL)) 1786 goto unbusy_ret; 1787 if (p != NULL) 1788 vm_page_xunbusy(p); 1789 } 1790 return (true); 1791 1792 unbusy_ret: 1793 if (p != NULL) 1794 vm_page_xunbusy(p); 1795 return (false); 1796 } 1797 1798 static void 1799 vm_object_collapse_scan(vm_object_t object) 1800 { 1801 vm_object_t backing_object; 1802 vm_page_t next, p, pp; 1803 vm_pindex_t backing_offset_index, new_pindex; 1804 1805 VM_OBJECT_ASSERT_WLOCKED(object); 1806 VM_OBJECT_ASSERT_WLOCKED(object->backing_object); 1807 1808 backing_object = object->backing_object; 1809 backing_offset_index = OFF_TO_IDX(object->backing_object_offset); 1810 1811 /* 1812 * Our scan 1813 */ 1814 for (p = TAILQ_FIRST(&backing_object->memq); p != NULL; p = next) { 1815 next = TAILQ_NEXT(p, listq); 1816 new_pindex = p->pindex - backing_offset_index; 1817 1818 /* 1819 * Check for busy page 1820 */ 1821 if (vm_page_tryxbusy(p) == 0) { 1822 next = vm_object_collapse_scan_wait(object, p); 1823 continue; 1824 } 1825 1826 KASSERT(object->backing_object == backing_object, 1827 ("vm_object_collapse_scan: backing object mismatch %p != %p", 1828 object->backing_object, backing_object)); 1829 KASSERT(p->object == backing_object, 1830 ("vm_object_collapse_scan: object mismatch %p != %p", 1831 p->object, backing_object)); 1832 1833 if (p->pindex < backing_offset_index || 1834 new_pindex >= object->size) { 1835 vm_pager_freespace(backing_object, p->pindex, 1); 1836 1837 KASSERT(!pmap_page_is_mapped(p), 1838 ("freeing mapped page %p", p)); 1839 if (vm_page_remove(p)) 1840 vm_page_free(p); 1841 continue; 1842 } 1843 1844 if (!vm_page_all_valid(p)) { 1845 KASSERT(!pmap_page_is_mapped(p), 1846 ("freeing mapped page %p", p)); 1847 if (vm_page_remove(p)) 1848 vm_page_free(p); 1849 continue; 1850 } 1851 1852 pp = vm_page_lookup(object, new_pindex); 1853 if (pp != NULL && vm_page_tryxbusy(pp) == 0) { 1854 vm_page_xunbusy(p); 1855 /* 1856 * The page in the parent is busy and possibly not 1857 * (yet) valid. Until its state is finalized by the 1858 * busy bit owner, we can't tell whether it shadows the 1859 * original page. 1860 */ 1861 next = vm_object_collapse_scan_wait(object, pp); 1862 continue; 1863 } 1864 1865 if (pp != NULL && vm_page_none_valid(pp)) { 1866 /* 1867 * The page was invalid in the parent. Likely placed 1868 * there by an incomplete fault. Just remove and 1869 * ignore. p can replace it. 1870 */ 1871 if (vm_page_remove(pp)) 1872 vm_page_free(pp); 1873 pp = NULL; 1874 } 1875 1876 if (pp != NULL || vm_pager_has_page(object, new_pindex, NULL, 1877 NULL)) { 1878 /* 1879 * The page already exists in the parent OR swap exists 1880 * for this location in the parent. Leave the parent's 1881 * page alone. Destroy the original page from the 1882 * backing object. 1883 */ 1884 vm_pager_freespace(backing_object, p->pindex, 1); 1885 KASSERT(!pmap_page_is_mapped(p), 1886 ("freeing mapped page %p", p)); 1887 if (vm_page_remove(p)) 1888 vm_page_free(p); 1889 if (pp != NULL) 1890 vm_page_xunbusy(pp); 1891 continue; 1892 } 1893 1894 /* 1895 * Page does not exist in parent, rename the page from the 1896 * backing object to the main object. 1897 * 1898 * If the page was mapped to a process, it can remain mapped 1899 * through the rename. vm_page_rename() will dirty the page. 1900 */ 1901 if (vm_page_rename(p, object, new_pindex)) { 1902 vm_page_xunbusy(p); 1903 next = vm_object_collapse_scan_wait(object, NULL); 1904 continue; 1905 } 1906 1907 /* Use the old pindex to free the right page. */ 1908 vm_pager_freespace(backing_object, new_pindex + 1909 backing_offset_index, 1); 1910 1911 #if VM_NRESERVLEVEL > 0 1912 /* 1913 * Rename the reservation. 1914 */ 1915 vm_reserv_rename(p, object, backing_object, 1916 backing_offset_index); 1917 #endif 1918 vm_page_xunbusy(p); 1919 } 1920 return; 1921 } 1922 1923 /* 1924 * vm_object_collapse: 1925 * 1926 * Collapse an object with the object backing it. 1927 * Pages in the backing object are moved into the 1928 * parent, and the backing object is deallocated. 1929 */ 1930 void 1931 vm_object_collapse(vm_object_t object) 1932 { 1933 vm_object_t backing_object, new_backing_object; 1934 1935 VM_OBJECT_ASSERT_WLOCKED(object); 1936 1937 while (TRUE) { 1938 KASSERT((object->flags & (OBJ_DEAD | OBJ_ANON)) == OBJ_ANON, 1939 ("collapsing invalid object")); 1940 1941 /* 1942 * Wait for the backing_object to finish any pending 1943 * collapse so that the caller sees the shortest possible 1944 * shadow chain. 1945 */ 1946 backing_object = vm_object_backing_collapse_wait(object); 1947 if (backing_object == NULL) 1948 return; 1949 1950 KASSERT(object->ref_count > 0 && 1951 object->ref_count > atomic_load_int(&object->shadow_count), 1952 ("collapse with invalid ref %d or shadow %d count.", 1953 object->ref_count, atomic_load_int(&object->shadow_count))); 1954 KASSERT((backing_object->flags & 1955 (OBJ_COLLAPSING | OBJ_DEAD)) == 0, 1956 ("vm_object_collapse: Backing object already collapsing.")); 1957 KASSERT((object->flags & (OBJ_COLLAPSING | OBJ_DEAD)) == 0, 1958 ("vm_object_collapse: object is already collapsing.")); 1959 1960 /* 1961 * We know that we can either collapse the backing object if 1962 * the parent is the only reference to it, or (perhaps) have 1963 * the parent bypass the object if the parent happens to shadow 1964 * all the resident pages in the entire backing object. 1965 */ 1966 if (backing_object->ref_count == 1) { 1967 KASSERT(atomic_load_int(&backing_object->shadow_count) 1968 == 1, 1969 ("vm_object_collapse: shadow_count: %d", 1970 atomic_load_int(&backing_object->shadow_count))); 1971 vm_object_pip_add(object, 1); 1972 vm_object_set_flag(object, OBJ_COLLAPSING); 1973 vm_object_pip_add(backing_object, 1); 1974 vm_object_set_flag(backing_object, OBJ_DEAD); 1975 1976 /* 1977 * If there is exactly one reference to the backing 1978 * object, we can collapse it into the parent. 1979 */ 1980 vm_object_collapse_scan(object); 1981 1982 #if VM_NRESERVLEVEL > 0 1983 /* 1984 * Break any reservations from backing_object. 1985 */ 1986 if (__predict_false(!LIST_EMPTY(&backing_object->rvq))) 1987 vm_reserv_break_all(backing_object); 1988 #endif 1989 1990 /* 1991 * Move the pager from backing_object to object. 1992 */ 1993 if ((backing_object->flags & OBJ_SWAP) != 0) { 1994 /* 1995 * swap_pager_copy() can sleep, in which case 1996 * the backing_object's and object's locks are 1997 * released and reacquired. 1998 * Since swap_pager_copy() is being asked to 1999 * destroy backing_object, it will change the 2000 * type to OBJT_DEFAULT. 2001 */ 2002 swap_pager_copy( 2003 backing_object, 2004 object, 2005 OFF_TO_IDX(object->backing_object_offset), TRUE); 2006 } 2007 2008 /* 2009 * Object now shadows whatever backing_object did. 2010 */ 2011 vm_object_clear_flag(object, OBJ_COLLAPSING); 2012 vm_object_backing_transfer(object, backing_object); 2013 object->backing_object_offset += 2014 backing_object->backing_object_offset; 2015 VM_OBJECT_WUNLOCK(object); 2016 vm_object_pip_wakeup(object); 2017 2018 /* 2019 * Discard backing_object. 2020 * 2021 * Since the backing object has no pages, no pager left, 2022 * and no object references within it, all that is 2023 * necessary is to dispose of it. 2024 */ 2025 KASSERT(backing_object->ref_count == 1, ( 2026 "backing_object %p was somehow re-referenced during collapse!", 2027 backing_object)); 2028 vm_object_pip_wakeup(backing_object); 2029 (void)refcount_release(&backing_object->ref_count); 2030 vm_object_terminate(backing_object); 2031 counter_u64_add(object_collapses, 1); 2032 VM_OBJECT_WLOCK(object); 2033 } else { 2034 /* 2035 * If we do not entirely shadow the backing object, 2036 * there is nothing we can do so we give up. 2037 * 2038 * The object lock and backing_object lock must not 2039 * be dropped during this sequence. 2040 */ 2041 if (!vm_object_scan_all_shadowed(object)) { 2042 VM_OBJECT_WUNLOCK(backing_object); 2043 break; 2044 } 2045 2046 /* 2047 * Make the parent shadow the next object in the 2048 * chain. Deallocating backing_object will not remove 2049 * it, since its reference count is at least 2. 2050 */ 2051 vm_object_backing_remove_locked(object); 2052 new_backing_object = backing_object->backing_object; 2053 if (new_backing_object != NULL) { 2054 vm_object_backing_insert_ref(object, 2055 new_backing_object); 2056 object->backing_object_offset += 2057 backing_object->backing_object_offset; 2058 } 2059 2060 /* 2061 * Drop the reference count on backing_object. Since 2062 * its ref_count was at least 2, it will not vanish. 2063 */ 2064 (void)refcount_release(&backing_object->ref_count); 2065 KASSERT(backing_object->ref_count >= 1, ( 2066 "backing_object %p was somehow dereferenced during collapse!", 2067 backing_object)); 2068 VM_OBJECT_WUNLOCK(backing_object); 2069 counter_u64_add(object_bypasses, 1); 2070 } 2071 2072 /* 2073 * Try again with this object's new backing object. 2074 */ 2075 } 2076 } 2077 2078 /* 2079 * vm_object_page_remove: 2080 * 2081 * For the given object, either frees or invalidates each of the 2082 * specified pages. In general, a page is freed. However, if a page is 2083 * wired for any reason other than the existence of a managed, wired 2084 * mapping, then it may be invalidated but not removed from the object. 2085 * Pages are specified by the given range ["start", "end") and the option 2086 * OBJPR_CLEANONLY. As a special case, if "end" is zero, then the range 2087 * extends from "start" to the end of the object. If the option 2088 * OBJPR_CLEANONLY is specified, then only the non-dirty pages within the 2089 * specified range are affected. If the option OBJPR_NOTMAPPED is 2090 * specified, then the pages within the specified range must have no 2091 * mappings. Otherwise, if this option is not specified, any mappings to 2092 * the specified pages are removed before the pages are freed or 2093 * invalidated. 2094 * 2095 * In general, this operation should only be performed on objects that 2096 * contain managed pages. There are, however, two exceptions. First, it 2097 * is performed on the kernel and kmem objects by vm_map_entry_delete(). 2098 * Second, it is used by msync(..., MS_INVALIDATE) to invalidate device- 2099 * backed pages. In both of these cases, the option OBJPR_CLEANONLY must 2100 * not be specified and the option OBJPR_NOTMAPPED must be specified. 2101 * 2102 * The object must be locked. 2103 */ 2104 void 2105 vm_object_page_remove(vm_object_t object, vm_pindex_t start, vm_pindex_t end, 2106 int options) 2107 { 2108 vm_page_t p, next; 2109 2110 VM_OBJECT_ASSERT_WLOCKED(object); 2111 KASSERT((object->flags & OBJ_UNMANAGED) == 0 || 2112 (options & (OBJPR_CLEANONLY | OBJPR_NOTMAPPED)) == OBJPR_NOTMAPPED, 2113 ("vm_object_page_remove: illegal options for object %p", object)); 2114 if (object->resident_page_count == 0) 2115 return; 2116 vm_object_pip_add(object, 1); 2117 again: 2118 p = vm_page_find_least(object, start); 2119 2120 /* 2121 * Here, the variable "p" is either (1) the page with the least pindex 2122 * greater than or equal to the parameter "start" or (2) NULL. 2123 */ 2124 for (; p != NULL && (p->pindex < end || end == 0); p = next) { 2125 next = TAILQ_NEXT(p, listq); 2126 2127 /* 2128 * Skip invalid pages if asked to do so. Try to avoid acquiring 2129 * the busy lock, as some consumers rely on this to avoid 2130 * deadlocks. 2131 * 2132 * A thread may concurrently transition the page from invalid to 2133 * valid using only the busy lock, so the result of this check 2134 * is immediately stale. It is up to consumers to handle this, 2135 * for instance by ensuring that all invalid->valid transitions 2136 * happen with a mutex held, as may be possible for a 2137 * filesystem. 2138 */ 2139 if ((options & OBJPR_VALIDONLY) != 0 && vm_page_none_valid(p)) 2140 continue; 2141 2142 /* 2143 * If the page is wired for any reason besides the existence 2144 * of managed, wired mappings, then it cannot be freed. For 2145 * example, fictitious pages, which represent device memory, 2146 * are inherently wired and cannot be freed. They can, 2147 * however, be invalidated if the option OBJPR_CLEANONLY is 2148 * not specified. 2149 */ 2150 if (vm_page_tryxbusy(p) == 0) { 2151 if (vm_page_busy_sleep(p, "vmopar", 0)) 2152 VM_OBJECT_WLOCK(object); 2153 goto again; 2154 } 2155 if ((options & OBJPR_VALIDONLY) != 0 && vm_page_none_valid(p)) { 2156 vm_page_xunbusy(p); 2157 continue; 2158 } 2159 if (vm_page_wired(p)) { 2160 wired: 2161 if ((options & OBJPR_NOTMAPPED) == 0 && 2162 object->ref_count != 0) 2163 pmap_remove_all(p); 2164 if ((options & OBJPR_CLEANONLY) == 0) { 2165 vm_page_invalid(p); 2166 vm_page_undirty(p); 2167 } 2168 vm_page_xunbusy(p); 2169 continue; 2170 } 2171 KASSERT((p->flags & PG_FICTITIOUS) == 0, 2172 ("vm_object_page_remove: page %p is fictitious", p)); 2173 if ((options & OBJPR_CLEANONLY) != 0 && 2174 !vm_page_none_valid(p)) { 2175 if ((options & OBJPR_NOTMAPPED) == 0 && 2176 object->ref_count != 0 && 2177 !vm_page_try_remove_write(p)) 2178 goto wired; 2179 if (p->dirty != 0) { 2180 vm_page_xunbusy(p); 2181 continue; 2182 } 2183 } 2184 if ((options & OBJPR_NOTMAPPED) == 0 && 2185 object->ref_count != 0 && !vm_page_try_remove_all(p)) 2186 goto wired; 2187 vm_page_free(p); 2188 } 2189 vm_object_pip_wakeup(object); 2190 2191 vm_pager_freespace(object, start, (end == 0 ? object->size : end) - 2192 start); 2193 } 2194 2195 /* 2196 * vm_object_page_noreuse: 2197 * 2198 * For the given object, attempt to move the specified pages to 2199 * the head of the inactive queue. This bypasses regular LRU 2200 * operation and allows the pages to be reused quickly under memory 2201 * pressure. If a page is wired for any reason, then it will not 2202 * be queued. Pages are specified by the range ["start", "end"). 2203 * As a special case, if "end" is zero, then the range extends from 2204 * "start" to the end of the object. 2205 * 2206 * This operation should only be performed on objects that 2207 * contain non-fictitious, managed pages. 2208 * 2209 * The object must be locked. 2210 */ 2211 void 2212 vm_object_page_noreuse(vm_object_t object, vm_pindex_t start, vm_pindex_t end) 2213 { 2214 vm_page_t p, next; 2215 2216 VM_OBJECT_ASSERT_LOCKED(object); 2217 KASSERT((object->flags & (OBJ_FICTITIOUS | OBJ_UNMANAGED)) == 0, 2218 ("vm_object_page_noreuse: illegal object %p", object)); 2219 if (object->resident_page_count == 0) 2220 return; 2221 p = vm_page_find_least(object, start); 2222 2223 /* 2224 * Here, the variable "p" is either (1) the page with the least pindex 2225 * greater than or equal to the parameter "start" or (2) NULL. 2226 */ 2227 for (; p != NULL && (p->pindex < end || end == 0); p = next) { 2228 next = TAILQ_NEXT(p, listq); 2229 vm_page_deactivate_noreuse(p); 2230 } 2231 } 2232 2233 /* 2234 * Populate the specified range of the object with valid pages. Returns 2235 * TRUE if the range is successfully populated and FALSE otherwise. 2236 * 2237 * Note: This function should be optimized to pass a larger array of 2238 * pages to vm_pager_get_pages() before it is applied to a non- 2239 * OBJT_DEVICE object. 2240 * 2241 * The object must be locked. 2242 */ 2243 boolean_t 2244 vm_object_populate(vm_object_t object, vm_pindex_t start, vm_pindex_t end) 2245 { 2246 vm_page_t m; 2247 vm_pindex_t pindex; 2248 int rv; 2249 2250 VM_OBJECT_ASSERT_WLOCKED(object); 2251 for (pindex = start; pindex < end; pindex++) { 2252 rv = vm_page_grab_valid(&m, object, pindex, VM_ALLOC_NORMAL); 2253 if (rv != VM_PAGER_OK) 2254 break; 2255 2256 /* 2257 * Keep "m" busy because a subsequent iteration may unlock 2258 * the object. 2259 */ 2260 } 2261 if (pindex > start) { 2262 m = vm_page_lookup(object, start); 2263 while (m != NULL && m->pindex < pindex) { 2264 vm_page_xunbusy(m); 2265 m = TAILQ_NEXT(m, listq); 2266 } 2267 } 2268 return (pindex == end); 2269 } 2270 2271 /* 2272 * Routine: vm_object_coalesce 2273 * Function: Coalesces two objects backing up adjoining 2274 * regions of memory into a single object. 2275 * 2276 * returns TRUE if objects were combined. 2277 * 2278 * NOTE: Only works at the moment if the second object is NULL - 2279 * if it's not, which object do we lock first? 2280 * 2281 * Parameters: 2282 * prev_object First object to coalesce 2283 * prev_offset Offset into prev_object 2284 * prev_size Size of reference to prev_object 2285 * next_size Size of reference to the second object 2286 * reserved Indicator that extension region has 2287 * swap accounted for 2288 * 2289 * Conditions: 2290 * The object must *not* be locked. 2291 */ 2292 boolean_t 2293 vm_object_coalesce(vm_object_t prev_object, vm_ooffset_t prev_offset, 2294 vm_size_t prev_size, vm_size_t next_size, boolean_t reserved) 2295 { 2296 vm_pindex_t next_pindex; 2297 2298 if (prev_object == NULL) 2299 return (TRUE); 2300 if ((prev_object->flags & OBJ_ANON) == 0) 2301 return (FALSE); 2302 2303 VM_OBJECT_WLOCK(prev_object); 2304 /* 2305 * Try to collapse the object first. 2306 */ 2307 vm_object_collapse(prev_object); 2308 2309 /* 2310 * Can't coalesce if: . more than one reference . paged out . shadows 2311 * another object . has a copy elsewhere (any of which mean that the 2312 * pages not mapped to prev_entry may be in use anyway) 2313 */ 2314 if (prev_object->backing_object != NULL) { 2315 VM_OBJECT_WUNLOCK(prev_object); 2316 return (FALSE); 2317 } 2318 2319 prev_size >>= PAGE_SHIFT; 2320 next_size >>= PAGE_SHIFT; 2321 next_pindex = OFF_TO_IDX(prev_offset) + prev_size; 2322 2323 if (prev_object->ref_count > 1 && 2324 prev_object->size != next_pindex && 2325 (prev_object->flags & OBJ_ONEMAPPING) == 0) { 2326 VM_OBJECT_WUNLOCK(prev_object); 2327 return (FALSE); 2328 } 2329 2330 /* 2331 * Account for the charge. 2332 */ 2333 if (prev_object->cred != NULL) { 2334 /* 2335 * If prev_object was charged, then this mapping, 2336 * although not charged now, may become writable 2337 * later. Non-NULL cred in the object would prevent 2338 * swap reservation during enabling of the write 2339 * access, so reserve swap now. Failed reservation 2340 * cause allocation of the separate object for the map 2341 * entry, and swap reservation for this entry is 2342 * managed in appropriate time. 2343 */ 2344 if (!reserved && !swap_reserve_by_cred(ptoa(next_size), 2345 prev_object->cred)) { 2346 VM_OBJECT_WUNLOCK(prev_object); 2347 return (FALSE); 2348 } 2349 prev_object->charge += ptoa(next_size); 2350 } 2351 2352 /* 2353 * Remove any pages that may still be in the object from a previous 2354 * deallocation. 2355 */ 2356 if (next_pindex < prev_object->size) { 2357 vm_object_page_remove(prev_object, next_pindex, next_pindex + 2358 next_size, 0); 2359 #if 0 2360 if (prev_object->cred != NULL) { 2361 KASSERT(prev_object->charge >= 2362 ptoa(prev_object->size - next_pindex), 2363 ("object %p overcharged 1 %jx %jx", prev_object, 2364 (uintmax_t)next_pindex, (uintmax_t)next_size)); 2365 prev_object->charge -= ptoa(prev_object->size - 2366 next_pindex); 2367 } 2368 #endif 2369 } 2370 2371 /* 2372 * Extend the object if necessary. 2373 */ 2374 if (next_pindex + next_size > prev_object->size) 2375 prev_object->size = next_pindex + next_size; 2376 2377 VM_OBJECT_WUNLOCK(prev_object); 2378 return (TRUE); 2379 } 2380 2381 void 2382 vm_object_set_writeable_dirty_(vm_object_t object) 2383 { 2384 atomic_add_int(&object->generation, 1); 2385 } 2386 2387 bool 2388 vm_object_mightbedirty_(vm_object_t object) 2389 { 2390 return (object->generation != object->cleangeneration); 2391 } 2392 2393 /* 2394 * vm_object_unwire: 2395 * 2396 * For each page offset within the specified range of the given object, 2397 * find the highest-level page in the shadow chain and unwire it. A page 2398 * must exist at every page offset, and the highest-level page must be 2399 * wired. 2400 */ 2401 void 2402 vm_object_unwire(vm_object_t object, vm_ooffset_t offset, vm_size_t length, 2403 uint8_t queue) 2404 { 2405 vm_object_t tobject, t1object; 2406 vm_page_t m, tm; 2407 vm_pindex_t end_pindex, pindex, tpindex; 2408 int depth, locked_depth; 2409 2410 KASSERT((offset & PAGE_MASK) == 0, 2411 ("vm_object_unwire: offset is not page aligned")); 2412 KASSERT((length & PAGE_MASK) == 0, 2413 ("vm_object_unwire: length is not a multiple of PAGE_SIZE")); 2414 /* The wired count of a fictitious page never changes. */ 2415 if ((object->flags & OBJ_FICTITIOUS) != 0) 2416 return; 2417 pindex = OFF_TO_IDX(offset); 2418 end_pindex = pindex + atop(length); 2419 again: 2420 locked_depth = 1; 2421 VM_OBJECT_RLOCK(object); 2422 m = vm_page_find_least(object, pindex); 2423 while (pindex < end_pindex) { 2424 if (m == NULL || pindex < m->pindex) { 2425 /* 2426 * The first object in the shadow chain doesn't 2427 * contain a page at the current index. Therefore, 2428 * the page must exist in a backing object. 2429 */ 2430 tobject = object; 2431 tpindex = pindex; 2432 depth = 0; 2433 do { 2434 tpindex += 2435 OFF_TO_IDX(tobject->backing_object_offset); 2436 tobject = tobject->backing_object; 2437 KASSERT(tobject != NULL, 2438 ("vm_object_unwire: missing page")); 2439 if ((tobject->flags & OBJ_FICTITIOUS) != 0) 2440 goto next_page; 2441 depth++; 2442 if (depth == locked_depth) { 2443 locked_depth++; 2444 VM_OBJECT_RLOCK(tobject); 2445 } 2446 } while ((tm = vm_page_lookup(tobject, tpindex)) == 2447 NULL); 2448 } else { 2449 tm = m; 2450 m = TAILQ_NEXT(m, listq); 2451 } 2452 if (vm_page_trysbusy(tm) == 0) { 2453 for (tobject = object; locked_depth >= 1; 2454 locked_depth--) { 2455 t1object = tobject->backing_object; 2456 if (tm->object != tobject) 2457 VM_OBJECT_RUNLOCK(tobject); 2458 tobject = t1object; 2459 } 2460 tobject = tm->object; 2461 if (!vm_page_busy_sleep(tm, "unwbo", 2462 VM_ALLOC_IGN_SBUSY)) 2463 VM_OBJECT_RUNLOCK(tobject); 2464 goto again; 2465 } 2466 vm_page_unwire(tm, queue); 2467 vm_page_sunbusy(tm); 2468 next_page: 2469 pindex++; 2470 } 2471 /* Release the accumulated object locks. */ 2472 for (tobject = object; locked_depth >= 1; locked_depth--) { 2473 t1object = tobject->backing_object; 2474 VM_OBJECT_RUNLOCK(tobject); 2475 tobject = t1object; 2476 } 2477 } 2478 2479 /* 2480 * Return the vnode for the given object, or NULL if none exists. 2481 * For tmpfs objects, the function may return NULL if there is 2482 * no vnode allocated at the time of the call. 2483 */ 2484 struct vnode * 2485 vm_object_vnode(vm_object_t object) 2486 { 2487 struct vnode *vp; 2488 2489 VM_OBJECT_ASSERT_LOCKED(object); 2490 vm_pager_getvp(object, &vp, NULL); 2491 return (vp); 2492 } 2493 2494 /* 2495 * Busy the vm object. This prevents new pages belonging to the object from 2496 * becoming busy. Existing pages persist as busy. Callers are responsible 2497 * for checking page state before proceeding. 2498 */ 2499 void 2500 vm_object_busy(vm_object_t obj) 2501 { 2502 2503 VM_OBJECT_ASSERT_LOCKED(obj); 2504 2505 blockcount_acquire(&obj->busy, 1); 2506 /* The fence is required to order loads of page busy. */ 2507 atomic_thread_fence_acq_rel(); 2508 } 2509 2510 void 2511 vm_object_unbusy(vm_object_t obj) 2512 { 2513 2514 blockcount_release(&obj->busy, 1); 2515 } 2516 2517 void 2518 vm_object_busy_wait(vm_object_t obj, const char *wmesg) 2519 { 2520 2521 VM_OBJECT_ASSERT_UNLOCKED(obj); 2522 2523 (void)blockcount_sleep(&obj->busy, NULL, wmesg, PVM); 2524 } 2525 2526 /* 2527 * This function aims to determine if the object is mapped, 2528 * specifically, if it is referenced by a vm_map_entry. Because 2529 * objects occasionally acquire transient references that do not 2530 * represent a mapping, the method used here is inexact. However, it 2531 * has very low overhead and is good enough for the advisory 2532 * vm.vmtotal sysctl. 2533 */ 2534 bool 2535 vm_object_is_active(vm_object_t obj) 2536 { 2537 2538 return (obj->ref_count > atomic_load_int(&obj->shadow_count)); 2539 } 2540 2541 static int 2542 vm_object_list_handler(struct sysctl_req *req, bool swap_only) 2543 { 2544 struct kinfo_vmobject *kvo; 2545 char *fullpath, *freepath; 2546 struct vnode *vp; 2547 struct vattr va; 2548 vm_object_t obj; 2549 vm_page_t m; 2550 u_long sp; 2551 int count, error; 2552 2553 if (req->oldptr == NULL) { 2554 /* 2555 * If an old buffer has not been provided, generate an 2556 * estimate of the space needed for a subsequent call. 2557 */ 2558 mtx_lock(&vm_object_list_mtx); 2559 count = 0; 2560 TAILQ_FOREACH(obj, &vm_object_list, object_list) { 2561 if (obj->type == OBJT_DEAD) 2562 continue; 2563 count++; 2564 } 2565 mtx_unlock(&vm_object_list_mtx); 2566 return (SYSCTL_OUT(req, NULL, sizeof(struct kinfo_vmobject) * 2567 count * 11 / 10)); 2568 } 2569 2570 kvo = malloc(sizeof(*kvo), M_TEMP, M_WAITOK); 2571 error = 0; 2572 2573 /* 2574 * VM objects are type stable and are never removed from the 2575 * list once added. This allows us to safely read obj->object_list 2576 * after reacquiring the VM object lock. 2577 */ 2578 mtx_lock(&vm_object_list_mtx); 2579 TAILQ_FOREACH(obj, &vm_object_list, object_list) { 2580 if (obj->type == OBJT_DEAD || 2581 (swap_only && (obj->flags & (OBJ_ANON | OBJ_SWAP)) == 0)) 2582 continue; 2583 VM_OBJECT_RLOCK(obj); 2584 if (obj->type == OBJT_DEAD || 2585 (swap_only && (obj->flags & (OBJ_ANON | OBJ_SWAP)) == 0)) { 2586 VM_OBJECT_RUNLOCK(obj); 2587 continue; 2588 } 2589 mtx_unlock(&vm_object_list_mtx); 2590 kvo->kvo_size = ptoa(obj->size); 2591 kvo->kvo_resident = obj->resident_page_count; 2592 kvo->kvo_ref_count = obj->ref_count; 2593 kvo->kvo_shadow_count = atomic_load_int(&obj->shadow_count); 2594 kvo->kvo_memattr = obj->memattr; 2595 kvo->kvo_active = 0; 2596 kvo->kvo_inactive = 0; 2597 if (!swap_only) { 2598 TAILQ_FOREACH(m, &obj->memq, listq) { 2599 /* 2600 * A page may belong to the object but be 2601 * dequeued and set to PQ_NONE while the 2602 * object lock is not held. This makes the 2603 * reads of m->queue below racy, and we do not 2604 * count pages set to PQ_NONE. However, this 2605 * sysctl is only meant to give an 2606 * approximation of the system anyway. 2607 */ 2608 if (m->a.queue == PQ_ACTIVE) 2609 kvo->kvo_active++; 2610 else if (m->a.queue == PQ_INACTIVE) 2611 kvo->kvo_inactive++; 2612 } 2613 } 2614 2615 kvo->kvo_vn_fileid = 0; 2616 kvo->kvo_vn_fsid = 0; 2617 kvo->kvo_vn_fsid_freebsd11 = 0; 2618 freepath = NULL; 2619 fullpath = ""; 2620 vp = NULL; 2621 kvo->kvo_type = vm_object_kvme_type(obj, swap_only ? NULL : &vp); 2622 if (vp != NULL) { 2623 vref(vp); 2624 } else if ((obj->flags & OBJ_ANON) != 0) { 2625 MPASS(kvo->kvo_type == KVME_TYPE_DEFAULT || 2626 kvo->kvo_type == KVME_TYPE_SWAP); 2627 kvo->kvo_me = (uintptr_t)obj; 2628 /* tmpfs objs are reported as vnodes */ 2629 kvo->kvo_backing_obj = (uintptr_t)obj->backing_object; 2630 sp = swap_pager_swapped_pages(obj); 2631 kvo->kvo_swapped = sp > UINT32_MAX ? UINT32_MAX : sp; 2632 } 2633 VM_OBJECT_RUNLOCK(obj); 2634 if (vp != NULL) { 2635 vn_fullpath(vp, &fullpath, &freepath); 2636 vn_lock(vp, LK_SHARED | LK_RETRY); 2637 if (VOP_GETATTR(vp, &va, curthread->td_ucred) == 0) { 2638 kvo->kvo_vn_fileid = va.va_fileid; 2639 kvo->kvo_vn_fsid = va.va_fsid; 2640 kvo->kvo_vn_fsid_freebsd11 = va.va_fsid; 2641 /* truncate */ 2642 } 2643 vput(vp); 2644 } 2645 2646 strlcpy(kvo->kvo_path, fullpath, sizeof(kvo->kvo_path)); 2647 if (freepath != NULL) 2648 free(freepath, M_TEMP); 2649 2650 /* Pack record size down */ 2651 kvo->kvo_structsize = offsetof(struct kinfo_vmobject, kvo_path) 2652 + strlen(kvo->kvo_path) + 1; 2653 kvo->kvo_structsize = roundup(kvo->kvo_structsize, 2654 sizeof(uint64_t)); 2655 error = SYSCTL_OUT(req, kvo, kvo->kvo_structsize); 2656 maybe_yield(); 2657 mtx_lock(&vm_object_list_mtx); 2658 if (error) 2659 break; 2660 } 2661 mtx_unlock(&vm_object_list_mtx); 2662 free(kvo, M_TEMP); 2663 return (error); 2664 } 2665 2666 static int 2667 sysctl_vm_object_list(SYSCTL_HANDLER_ARGS) 2668 { 2669 return (vm_object_list_handler(req, false)); 2670 } 2671 2672 SYSCTL_PROC(_vm, OID_AUTO, objects, CTLTYPE_STRUCT | CTLFLAG_RW | CTLFLAG_SKIP | 2673 CTLFLAG_MPSAFE, NULL, 0, sysctl_vm_object_list, "S,kinfo_vmobject", 2674 "List of VM objects"); 2675 2676 static int 2677 sysctl_vm_object_list_swap(SYSCTL_HANDLER_ARGS) 2678 { 2679 return (vm_object_list_handler(req, true)); 2680 } 2681 2682 /* 2683 * This sysctl returns list of the anonymous or swap objects. Intent 2684 * is to provide stripped optimized list useful to analyze swap use. 2685 * Since technically non-swap (default) objects participate in the 2686 * shadow chains, and are converted to swap type as needed by swap 2687 * pager, we must report them. 2688 */ 2689 SYSCTL_PROC(_vm, OID_AUTO, swap_objects, 2690 CTLTYPE_STRUCT | CTLFLAG_RW | CTLFLAG_SKIP | CTLFLAG_MPSAFE, NULL, 0, 2691 sysctl_vm_object_list_swap, "S,kinfo_vmobject", 2692 "List of swap VM objects"); 2693 2694 #include "opt_ddb.h" 2695 #ifdef DDB 2696 #include <sys/kernel.h> 2697 2698 #include <sys/cons.h> 2699 2700 #include <ddb/ddb.h> 2701 2702 static int 2703 _vm_object_in_map(vm_map_t map, vm_object_t object, vm_map_entry_t entry) 2704 { 2705 vm_map_t tmpm; 2706 vm_map_entry_t tmpe; 2707 vm_object_t obj; 2708 2709 if (map == 0) 2710 return 0; 2711 2712 if (entry == 0) { 2713 VM_MAP_ENTRY_FOREACH(tmpe, map) { 2714 if (_vm_object_in_map(map, object, tmpe)) { 2715 return 1; 2716 } 2717 } 2718 } else if (entry->eflags & MAP_ENTRY_IS_SUB_MAP) { 2719 tmpm = entry->object.sub_map; 2720 VM_MAP_ENTRY_FOREACH(tmpe, tmpm) { 2721 if (_vm_object_in_map(tmpm, object, tmpe)) { 2722 return 1; 2723 } 2724 } 2725 } else if ((obj = entry->object.vm_object) != NULL) { 2726 for (; obj; obj = obj->backing_object) 2727 if (obj == object) { 2728 return 1; 2729 } 2730 } 2731 return 0; 2732 } 2733 2734 static int 2735 vm_object_in_map(vm_object_t object) 2736 { 2737 struct proc *p; 2738 2739 /* sx_slock(&allproc_lock); */ 2740 FOREACH_PROC_IN_SYSTEM(p) { 2741 if (!p->p_vmspace /* || (p->p_flag & (P_SYSTEM|P_WEXIT)) */) 2742 continue; 2743 if (_vm_object_in_map(&p->p_vmspace->vm_map, object, 0)) { 2744 /* sx_sunlock(&allproc_lock); */ 2745 return 1; 2746 } 2747 } 2748 /* sx_sunlock(&allproc_lock); */ 2749 if (_vm_object_in_map(kernel_map, object, 0)) 2750 return 1; 2751 return 0; 2752 } 2753 2754 DB_SHOW_COMMAND(vmochk, vm_object_check) 2755 { 2756 vm_object_t object; 2757 2758 /* 2759 * make sure that internal objs are in a map somewhere 2760 * and none have zero ref counts. 2761 */ 2762 TAILQ_FOREACH(object, &vm_object_list, object_list) { 2763 if ((object->flags & OBJ_ANON) != 0) { 2764 if (object->ref_count == 0) { 2765 db_printf("vmochk: internal obj has zero ref count: %ld\n", 2766 (long)object->size); 2767 } 2768 if (!vm_object_in_map(object)) { 2769 db_printf( 2770 "vmochk: internal obj is not in a map: " 2771 "ref: %d, size: %lu: 0x%lx, backing_object: %p\n", 2772 object->ref_count, (u_long)object->size, 2773 (u_long)object->size, 2774 (void *)object->backing_object); 2775 } 2776 } 2777 if (db_pager_quit) 2778 return; 2779 } 2780 } 2781 2782 /* 2783 * vm_object_print: [ debug ] 2784 */ 2785 DB_SHOW_COMMAND(object, vm_object_print_static) 2786 { 2787 /* XXX convert args. */ 2788 vm_object_t object = (vm_object_t)addr; 2789 boolean_t full = have_addr; 2790 2791 vm_page_t p; 2792 2793 /* XXX count is an (unused) arg. Avoid shadowing it. */ 2794 #define count was_count 2795 2796 int count; 2797 2798 if (object == NULL) 2799 return; 2800 2801 db_iprintf( 2802 "Object %p: type=%d, size=0x%jx, res=%d, ref=%d, flags=0x%x ruid %d charge %jx\n", 2803 object, (int)object->type, (uintmax_t)object->size, 2804 object->resident_page_count, object->ref_count, object->flags, 2805 object->cred ? object->cred->cr_ruid : -1, (uintmax_t)object->charge); 2806 db_iprintf(" sref=%d, backing_object(%d)=(%p)+0x%jx\n", 2807 atomic_load_int(&object->shadow_count), 2808 object->backing_object ? object->backing_object->ref_count : 0, 2809 object->backing_object, (uintmax_t)object->backing_object_offset); 2810 2811 if (!full) 2812 return; 2813 2814 db_indent += 2; 2815 count = 0; 2816 TAILQ_FOREACH(p, &object->memq, listq) { 2817 if (count == 0) 2818 db_iprintf("memory:="); 2819 else if (count == 6) { 2820 db_printf("\n"); 2821 db_iprintf(" ..."); 2822 count = 0; 2823 } else 2824 db_printf(","); 2825 count++; 2826 2827 db_printf("(off=0x%jx,page=0x%jx)", 2828 (uintmax_t)p->pindex, (uintmax_t)VM_PAGE_TO_PHYS(p)); 2829 2830 if (db_pager_quit) 2831 break; 2832 } 2833 if (count != 0) 2834 db_printf("\n"); 2835 db_indent -= 2; 2836 } 2837 2838 /* XXX. */ 2839 #undef count 2840 2841 /* XXX need this non-static entry for calling from vm_map_print. */ 2842 void 2843 vm_object_print( 2844 /* db_expr_t */ long addr, 2845 boolean_t have_addr, 2846 /* db_expr_t */ long count, 2847 char *modif) 2848 { 2849 vm_object_print_static(addr, have_addr, count, modif); 2850 } 2851 2852 DB_SHOW_COMMAND(vmopag, vm_object_print_pages) 2853 { 2854 vm_object_t object; 2855 vm_pindex_t fidx; 2856 vm_paddr_t pa; 2857 vm_page_t m, prev_m; 2858 int rcount; 2859 2860 TAILQ_FOREACH(object, &vm_object_list, object_list) { 2861 db_printf("new object: %p\n", (void *)object); 2862 if (db_pager_quit) 2863 return; 2864 2865 rcount = 0; 2866 fidx = 0; 2867 pa = -1; 2868 TAILQ_FOREACH(m, &object->memq, listq) { 2869 if (m->pindex > 128) 2870 break; 2871 if ((prev_m = TAILQ_PREV(m, pglist, listq)) != NULL && 2872 prev_m->pindex + 1 != m->pindex) { 2873 if (rcount) { 2874 db_printf(" index(%ld)run(%d)pa(0x%lx)\n", 2875 (long)fidx, rcount, (long)pa); 2876 if (db_pager_quit) 2877 return; 2878 rcount = 0; 2879 } 2880 } 2881 if (rcount && 2882 (VM_PAGE_TO_PHYS(m) == pa + rcount * PAGE_SIZE)) { 2883 ++rcount; 2884 continue; 2885 } 2886 if (rcount) { 2887 db_printf(" index(%ld)run(%d)pa(0x%lx)\n", 2888 (long)fidx, rcount, (long)pa); 2889 if (db_pager_quit) 2890 return; 2891 } 2892 fidx = m->pindex; 2893 pa = VM_PAGE_TO_PHYS(m); 2894 rcount = 1; 2895 } 2896 if (rcount) { 2897 db_printf(" index(%ld)run(%d)pa(0x%lx)\n", 2898 (long)fidx, rcount, (long)pa); 2899 if (db_pager_quit) 2900 return; 2901 } 2902 } 2903 } 2904 #endif /* DDB */ 2905