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