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