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 struct pctrie_iter pages; 1524 vm_page_t m; 1525 vm_object_t orig_object, new_object, backing_object; 1526 vm_pindex_t offidxstart; 1527 vm_size_t size; 1528 1529 orig_object = entry->object.vm_object; 1530 KASSERT((orig_object->flags & OBJ_ONEMAPPING) != 0, 1531 ("vm_object_split: Splitting object with multiple mappings.")); 1532 if ((orig_object->flags & OBJ_ANON) == 0) 1533 return; 1534 if (orig_object->ref_count <= 1) 1535 return; 1536 VM_OBJECT_WUNLOCK(orig_object); 1537 1538 offidxstart = OFF_TO_IDX(entry->offset); 1539 size = atop(entry->end - entry->start); 1540 1541 new_object = vm_object_allocate_anon(size, orig_object, 1542 orig_object->cred, ptoa(size)); 1543 1544 /* 1545 * We must wait for the orig_object to complete any in-progress 1546 * collapse so that the swap blocks are stable below. The 1547 * additional reference on backing_object by new object will 1548 * prevent further collapse operations until split completes. 1549 */ 1550 VM_OBJECT_WLOCK(orig_object); 1551 vm_object_collapse_wait(orig_object); 1552 1553 /* 1554 * At this point, the new object is still private, so the order in 1555 * which the original and new objects are locked does not matter. 1556 */ 1557 VM_OBJECT_WLOCK(new_object); 1558 new_object->domain = orig_object->domain; 1559 backing_object = orig_object->backing_object; 1560 if (backing_object != NULL) { 1561 vm_object_backing_insert_ref(new_object, backing_object); 1562 new_object->backing_object_offset = 1563 orig_object->backing_object_offset + entry->offset; 1564 } 1565 if (orig_object->cred != NULL) { 1566 crhold(orig_object->cred); 1567 KASSERT(orig_object->charge >= ptoa(size), 1568 ("orig_object->charge < 0")); 1569 orig_object->charge -= ptoa(size); 1570 } 1571 1572 /* 1573 * Mark the split operation so that swap_pager_getpages() knows 1574 * that the object is in transition. 1575 */ 1576 vm_object_set_flag(orig_object, OBJ_SPLIT); 1577 vm_page_iter_limit_init(&pages, orig_object, offidxstart + size); 1578 retry: 1579 KASSERT(pctrie_iter_is_reset(&pages), 1580 ("%s: pctrie_iter not reset for retry", __func__)); 1581 for (m = vm_radix_iter_lookup_ge(&pages, offidxstart); m != NULL; 1582 m = vm_radix_iter_step(&pages)) { 1583 /* 1584 * We must wait for pending I/O to complete before we can 1585 * rename the page. 1586 * 1587 * We do not have to VM_PROT_NONE the page as mappings should 1588 * not be changed by this operation. 1589 */ 1590 if (vm_page_tryxbusy(m) == 0) { 1591 VM_OBJECT_WUNLOCK(new_object); 1592 if (vm_page_busy_sleep(m, "spltwt", 0)) 1593 VM_OBJECT_WLOCK(orig_object); 1594 pctrie_iter_reset(&pages); 1595 VM_OBJECT_WLOCK(new_object); 1596 goto retry; 1597 } 1598 1599 /* 1600 * If the page was left invalid, it was likely placed there by 1601 * an incomplete fault. Just remove and ignore. 1602 * 1603 * One other possibility is that the map entry is wired, in 1604 * which case we must hang on to the page to avoid leaking it, 1605 * as the map entry owns the wiring. This case can arise if the 1606 * backing object is truncated by the pager. 1607 */ 1608 if (vm_page_none_valid(m) && entry->wired_count == 0) { 1609 if (vm_page_iter_remove(&pages, m)) 1610 vm_page_free(m); 1611 continue; 1612 } 1613 1614 /* vm_page_iter_rename() will dirty the page if it is valid. */ 1615 if (!vm_page_iter_rename(&pages, m, new_object, m->pindex - 1616 offidxstart)) { 1617 vm_page_xunbusy(m); 1618 VM_OBJECT_WUNLOCK(new_object); 1619 VM_OBJECT_WUNLOCK(orig_object); 1620 vm_radix_wait(); 1621 pctrie_iter_reset(&pages); 1622 VM_OBJECT_WLOCK(orig_object); 1623 VM_OBJECT_WLOCK(new_object); 1624 goto retry; 1625 } 1626 1627 #if VM_NRESERVLEVEL > 0 1628 /* 1629 * If some of the reservation's allocated pages remain with 1630 * the original object, then transferring the reservation to 1631 * the new object is neither particularly beneficial nor 1632 * particularly harmful as compared to leaving the reservation 1633 * with the original object. If, however, all of the 1634 * reservation's allocated pages are transferred to the new 1635 * object, then transferring the reservation is typically 1636 * beneficial. Determining which of these two cases applies 1637 * would be more costly than unconditionally renaming the 1638 * reservation. 1639 */ 1640 vm_reserv_rename(m, new_object, orig_object, offidxstart); 1641 #endif 1642 } 1643 1644 /* 1645 * swap_pager_copy() can sleep, in which case the orig_object's 1646 * and new_object's locks are released and reacquired. 1647 */ 1648 swap_pager_copy(orig_object, new_object, offidxstart, 0); 1649 1650 TAILQ_FOREACH(m, &new_object->memq, listq) 1651 vm_page_xunbusy(m); 1652 1653 vm_object_clear_flag(orig_object, OBJ_SPLIT); 1654 VM_OBJECT_WUNLOCK(orig_object); 1655 VM_OBJECT_WUNLOCK(new_object); 1656 entry->object.vm_object = new_object; 1657 entry->offset = 0LL; 1658 vm_object_deallocate(orig_object); 1659 VM_OBJECT_WLOCK(new_object); 1660 } 1661 1662 static vm_page_t 1663 vm_object_collapse_scan_wait(struct pctrie_iter *pages, vm_object_t object, 1664 vm_page_t p) 1665 { 1666 vm_object_t backing_object; 1667 1668 VM_OBJECT_ASSERT_WLOCKED(object); 1669 backing_object = object->backing_object; 1670 VM_OBJECT_ASSERT_WLOCKED(backing_object); 1671 1672 KASSERT(p == NULL || p->object == object || p->object == backing_object, 1673 ("invalid ownership %p %p %p", p, object, backing_object)); 1674 /* The page is only NULL when rename fails. */ 1675 if (p == NULL) { 1676 VM_OBJECT_WUNLOCK(object); 1677 VM_OBJECT_WUNLOCK(backing_object); 1678 vm_radix_wait(); 1679 VM_OBJECT_WLOCK(object); 1680 } else if (p->object == object) { 1681 VM_OBJECT_WUNLOCK(backing_object); 1682 if (vm_page_busy_sleep(p, "vmocol", 0)) 1683 VM_OBJECT_WLOCK(object); 1684 } else { 1685 VM_OBJECT_WUNLOCK(object); 1686 if (!vm_page_busy_sleep(p, "vmocol", 0)) 1687 VM_OBJECT_WUNLOCK(backing_object); 1688 VM_OBJECT_WLOCK(object); 1689 } 1690 VM_OBJECT_WLOCK(backing_object); 1691 vm_page_iter_init(pages, backing_object); 1692 return (vm_radix_iter_lookup_ge(pages, 0)); 1693 } 1694 1695 static void 1696 vm_object_collapse_scan(vm_object_t object) 1697 { 1698 struct pctrie_iter pages; 1699 vm_object_t backing_object; 1700 vm_page_t next, p, pp; 1701 vm_pindex_t backing_offset_index, new_pindex; 1702 1703 VM_OBJECT_ASSERT_WLOCKED(object); 1704 VM_OBJECT_ASSERT_WLOCKED(object->backing_object); 1705 1706 backing_object = object->backing_object; 1707 backing_offset_index = OFF_TO_IDX(object->backing_object_offset); 1708 1709 /* 1710 * Our scan 1711 */ 1712 vm_page_iter_init(&pages, backing_object); 1713 for (p = vm_radix_iter_lookup_ge(&pages, 0); p != NULL; p = next) { 1714 /* 1715 * Check for busy page 1716 */ 1717 if (vm_page_tryxbusy(p) == 0) { 1718 next = vm_object_collapse_scan_wait(&pages, object, p); 1719 continue; 1720 } 1721 1722 KASSERT(object->backing_object == backing_object, 1723 ("vm_object_collapse_scan: backing object mismatch %p != %p", 1724 object->backing_object, backing_object)); 1725 KASSERT(p->object == backing_object, 1726 ("vm_object_collapse_scan: object mismatch %p != %p", 1727 p->object, backing_object)); 1728 1729 if (p->pindex < backing_offset_index || object->size <= 1730 (new_pindex = p->pindex - backing_offset_index)) { 1731 vm_pager_freespace(backing_object, p->pindex, 1); 1732 1733 KASSERT(!pmap_page_is_mapped(p), 1734 ("freeing mapped page %p", p)); 1735 if (vm_page_iter_remove(&pages, p)) 1736 vm_page_free(p); 1737 next = vm_radix_iter_step(&pages); 1738 continue; 1739 } 1740 1741 if (!vm_page_all_valid(p)) { 1742 KASSERT(!pmap_page_is_mapped(p), 1743 ("freeing mapped page %p", p)); 1744 if (vm_page_iter_remove(&pages, p)) 1745 vm_page_free(p); 1746 next = vm_radix_iter_step(&pages); 1747 continue; 1748 } 1749 1750 pp = vm_page_lookup(object, new_pindex); 1751 if (pp != NULL && vm_page_tryxbusy(pp) == 0) { 1752 vm_page_xunbusy(p); 1753 /* 1754 * The page in the parent is busy and possibly not 1755 * (yet) valid. Until its state is finalized by the 1756 * busy bit owner, we can't tell whether it shadows the 1757 * original page. 1758 */ 1759 next = vm_object_collapse_scan_wait(&pages, object, pp); 1760 continue; 1761 } 1762 1763 if (pp != NULL && vm_page_none_valid(pp)) { 1764 /* 1765 * The page was invalid in the parent. Likely placed 1766 * there by an incomplete fault. Just remove and 1767 * ignore. p can replace it. 1768 */ 1769 if (vm_page_remove(pp)) 1770 vm_page_free(pp); 1771 pp = NULL; 1772 } 1773 1774 if (pp != NULL || vm_pager_has_page(object, new_pindex, NULL, 1775 NULL)) { 1776 /* 1777 * The page already exists in the parent OR swap exists 1778 * for this location in the parent. Leave the parent's 1779 * page alone. Destroy the original page from the 1780 * backing object. 1781 */ 1782 vm_pager_freespace(backing_object, p->pindex, 1); 1783 KASSERT(!pmap_page_is_mapped(p), 1784 ("freeing mapped page %p", p)); 1785 if (pp != NULL) 1786 vm_page_xunbusy(pp); 1787 if (vm_page_iter_remove(&pages, p)) 1788 vm_page_free(p); 1789 next = vm_radix_iter_step(&pages); 1790 continue; 1791 } 1792 1793 /* 1794 * Page does not exist in parent, rename the page from the 1795 * backing object to the main object. 1796 * 1797 * If the page was mapped to a process, it can remain mapped 1798 * through the rename. vm_page_iter_rename() will dirty the 1799 * page. 1800 */ 1801 if (!vm_page_iter_rename(&pages, p, object, new_pindex)) { 1802 vm_page_xunbusy(p); 1803 next = vm_object_collapse_scan_wait(&pages, object, 1804 NULL); 1805 continue; 1806 } 1807 1808 /* Use the old pindex to free the right page. */ 1809 vm_pager_freespace(backing_object, new_pindex + 1810 backing_offset_index, 1); 1811 1812 #if VM_NRESERVLEVEL > 0 1813 /* 1814 * Rename the reservation. 1815 */ 1816 vm_reserv_rename(p, object, backing_object, 1817 backing_offset_index); 1818 #endif 1819 vm_page_xunbusy(p); 1820 next = vm_radix_iter_step(&pages); 1821 } 1822 return; 1823 } 1824 1825 /* 1826 * vm_object_collapse: 1827 * 1828 * Collapse an object with the object backing it. 1829 * Pages in the backing object are moved into the 1830 * parent, and the backing object is deallocated. 1831 */ 1832 void 1833 vm_object_collapse(vm_object_t object) 1834 { 1835 vm_object_t backing_object, new_backing_object; 1836 1837 VM_OBJECT_ASSERT_WLOCKED(object); 1838 1839 while (TRUE) { 1840 KASSERT((object->flags & (OBJ_DEAD | OBJ_ANON)) == OBJ_ANON, 1841 ("collapsing invalid object")); 1842 1843 /* 1844 * Wait for the backing_object to finish any pending 1845 * collapse so that the caller sees the shortest possible 1846 * shadow chain. 1847 */ 1848 backing_object = vm_object_backing_collapse_wait(object); 1849 if (backing_object == NULL) 1850 return; 1851 1852 KASSERT(object->ref_count > 0 && 1853 object->ref_count > atomic_load_int(&object->shadow_count), 1854 ("collapse with invalid ref %d or shadow %d count.", 1855 object->ref_count, atomic_load_int(&object->shadow_count))); 1856 KASSERT((backing_object->flags & 1857 (OBJ_COLLAPSING | OBJ_DEAD)) == 0, 1858 ("vm_object_collapse: Backing object already collapsing.")); 1859 KASSERT((object->flags & (OBJ_COLLAPSING | OBJ_DEAD)) == 0, 1860 ("vm_object_collapse: object is already collapsing.")); 1861 1862 /* 1863 * We know that we can either collapse the backing object if 1864 * the parent is the only reference to it, or (perhaps) have 1865 * the parent bypass the object if the parent happens to shadow 1866 * all the resident pages in the entire backing object. 1867 */ 1868 if (backing_object->ref_count == 1) { 1869 KASSERT(atomic_load_int(&backing_object->shadow_count) 1870 == 1, 1871 ("vm_object_collapse: shadow_count: %d", 1872 atomic_load_int(&backing_object->shadow_count))); 1873 vm_object_pip_add(object, 1); 1874 vm_object_set_flag(object, OBJ_COLLAPSING); 1875 vm_object_pip_add(backing_object, 1); 1876 vm_object_set_flag(backing_object, OBJ_DEAD); 1877 1878 /* 1879 * If there is exactly one reference to the backing 1880 * object, we can collapse it into the parent. 1881 */ 1882 vm_object_collapse_scan(object); 1883 1884 /* 1885 * Move the pager from backing_object to object. 1886 * 1887 * swap_pager_copy() can sleep, in which case the 1888 * backing_object's and object's locks are released and 1889 * reacquired. 1890 */ 1891 swap_pager_copy(backing_object, object, 1892 OFF_TO_IDX(object->backing_object_offset), TRUE); 1893 1894 /* 1895 * Object now shadows whatever backing_object did. 1896 */ 1897 vm_object_clear_flag(object, OBJ_COLLAPSING); 1898 vm_object_backing_transfer(object, backing_object); 1899 object->backing_object_offset += 1900 backing_object->backing_object_offset; 1901 VM_OBJECT_WUNLOCK(object); 1902 vm_object_pip_wakeup(object); 1903 1904 /* 1905 * Discard backing_object. 1906 * 1907 * Since the backing object has no pages, no pager left, 1908 * and no object references within it, all that is 1909 * necessary is to dispose of it. 1910 */ 1911 KASSERT(backing_object->ref_count == 1, ( 1912 "backing_object %p was somehow re-referenced during collapse!", 1913 backing_object)); 1914 vm_object_pip_wakeup(backing_object); 1915 (void)refcount_release(&backing_object->ref_count); 1916 umtx_shm_object_terminated(backing_object); 1917 vm_object_terminate(backing_object); 1918 counter_u64_add(object_collapses, 1); 1919 VM_OBJECT_WLOCK(object); 1920 } else { 1921 /* 1922 * If we do not entirely shadow the backing object, 1923 * there is nothing we can do so we give up. 1924 * 1925 * The object lock and backing_object lock must not 1926 * be dropped during this sequence. 1927 */ 1928 if (!swap_pager_scan_all_shadowed(object)) { 1929 VM_OBJECT_WUNLOCK(backing_object); 1930 break; 1931 } 1932 1933 /* 1934 * Make the parent shadow the next object in the 1935 * chain. Deallocating backing_object will not remove 1936 * it, since its reference count is at least 2. 1937 */ 1938 vm_object_backing_remove_locked(object); 1939 new_backing_object = backing_object->backing_object; 1940 if (new_backing_object != NULL) { 1941 vm_object_backing_insert_ref(object, 1942 new_backing_object); 1943 object->backing_object_offset += 1944 backing_object->backing_object_offset; 1945 } 1946 1947 /* 1948 * Drop the reference count on backing_object. Since 1949 * its ref_count was at least 2, it will not vanish. 1950 */ 1951 (void)refcount_release(&backing_object->ref_count); 1952 KASSERT(backing_object->ref_count >= 1, ( 1953 "backing_object %p was somehow dereferenced during collapse!", 1954 backing_object)); 1955 VM_OBJECT_WUNLOCK(backing_object); 1956 counter_u64_add(object_bypasses, 1); 1957 } 1958 1959 /* 1960 * Try again with this object's new backing object. 1961 */ 1962 } 1963 } 1964 1965 /* 1966 * vm_object_page_remove: 1967 * 1968 * For the given object, either frees or invalidates each of the 1969 * specified pages. In general, a page is freed. However, if a page is 1970 * wired for any reason other than the existence of a managed, wired 1971 * mapping, then it may be invalidated but not removed from the object. 1972 * Pages are specified by the given range ["start", "end") and the option 1973 * OBJPR_CLEANONLY. As a special case, if "end" is zero, then the range 1974 * extends from "start" to the end of the object. If the option 1975 * OBJPR_CLEANONLY is specified, then only the non-dirty pages within the 1976 * specified range are affected. If the option OBJPR_NOTMAPPED is 1977 * specified, then the pages within the specified range must have no 1978 * mappings. Otherwise, if this option is not specified, any mappings to 1979 * the specified pages are removed before the pages are freed or 1980 * invalidated. 1981 * 1982 * In general, this operation should only be performed on objects that 1983 * contain managed pages. There are, however, two exceptions. First, it 1984 * is performed on the kernel and kmem objects by vm_map_entry_delete(). 1985 * Second, it is used by msync(..., MS_INVALIDATE) to invalidate device- 1986 * backed pages. In both of these cases, the option OBJPR_CLEANONLY must 1987 * not be specified and the option OBJPR_NOTMAPPED must be specified. 1988 * 1989 * The object must be locked. 1990 */ 1991 void 1992 vm_object_page_remove(vm_object_t object, vm_pindex_t start, vm_pindex_t end, 1993 int options) 1994 { 1995 struct pctrie_iter pages; 1996 vm_page_t p; 1997 1998 VM_OBJECT_ASSERT_WLOCKED(object); 1999 KASSERT((object->flags & OBJ_UNMANAGED) == 0 || 2000 (options & (OBJPR_CLEANONLY | OBJPR_NOTMAPPED)) == OBJPR_NOTMAPPED, 2001 ("vm_object_page_remove: illegal options for object %p", object)); 2002 if (object->resident_page_count == 0) 2003 return; 2004 vm_object_pip_add(object, 1); 2005 vm_page_iter_limit_init(&pages, object, end); 2006 again: 2007 KASSERT(pctrie_iter_is_reset(&pages), 2008 ("%s: pctrie_iter not reset for retry", __func__)); 2009 for (p = vm_radix_iter_lookup_ge(&pages, start); p != NULL; 2010 p = vm_radix_iter_step(&pages)) { 2011 /* 2012 * Skip invalid pages if asked to do so. Try to avoid acquiring 2013 * the busy lock, as some consumers rely on this to avoid 2014 * deadlocks. 2015 * 2016 * A thread may concurrently transition the page from invalid to 2017 * valid using only the busy lock, so the result of this check 2018 * is immediately stale. It is up to consumers to handle this, 2019 * for instance by ensuring that all invalid->valid transitions 2020 * happen with a mutex held, as may be possible for a 2021 * filesystem. 2022 */ 2023 if ((options & OBJPR_VALIDONLY) != 0 && vm_page_none_valid(p)) 2024 continue; 2025 2026 /* 2027 * If the page is wired for any reason besides the existence 2028 * of managed, wired mappings, then it cannot be freed. For 2029 * example, fictitious pages, which represent device memory, 2030 * are inherently wired and cannot be freed. They can, 2031 * however, be invalidated if the option OBJPR_CLEANONLY is 2032 * not specified. 2033 */ 2034 if (vm_page_tryxbusy(p) == 0) { 2035 if (vm_page_busy_sleep(p, "vmopar", 0)) 2036 VM_OBJECT_WLOCK(object); 2037 pctrie_iter_reset(&pages); 2038 goto again; 2039 } 2040 if ((options & OBJPR_VALIDONLY) != 0 && vm_page_none_valid(p)) { 2041 vm_page_xunbusy(p); 2042 continue; 2043 } 2044 if (vm_page_wired(p)) { 2045 wired: 2046 if ((options & OBJPR_NOTMAPPED) == 0 && 2047 object->ref_count != 0) 2048 pmap_remove_all(p); 2049 if ((options & OBJPR_CLEANONLY) == 0) { 2050 vm_page_invalid(p); 2051 vm_page_undirty(p); 2052 } 2053 vm_page_xunbusy(p); 2054 continue; 2055 } 2056 KASSERT((p->flags & PG_FICTITIOUS) == 0, 2057 ("vm_object_page_remove: page %p is fictitious", p)); 2058 if ((options & OBJPR_CLEANONLY) != 0 && 2059 !vm_page_none_valid(p)) { 2060 if ((options & OBJPR_NOTMAPPED) == 0 && 2061 object->ref_count != 0 && 2062 !vm_page_try_remove_write(p)) 2063 goto wired; 2064 if (p->dirty != 0) { 2065 vm_page_xunbusy(p); 2066 continue; 2067 } 2068 } 2069 if ((options & OBJPR_NOTMAPPED) == 0 && 2070 object->ref_count != 0 && !vm_page_try_remove_all(p)) 2071 goto wired; 2072 vm_page_iter_free(&pages, p); 2073 } 2074 vm_object_pip_wakeup(object); 2075 2076 vm_pager_freespace(object, start, (end == 0 ? object->size : end) - 2077 start); 2078 } 2079 2080 /* 2081 * vm_object_page_noreuse: 2082 * 2083 * For the given object, attempt to move the specified pages to 2084 * the head of the inactive queue. This bypasses regular LRU 2085 * operation and allows the pages to be reused quickly under memory 2086 * pressure. If a page is wired for any reason, then it will not 2087 * be queued. Pages are specified by the range ["start", "end"). 2088 * As a special case, if "end" is zero, then the range extends from 2089 * "start" to the end of the object. 2090 * 2091 * This operation should only be performed on objects that 2092 * contain non-fictitious, managed pages. 2093 * 2094 * The object must be locked. 2095 */ 2096 void 2097 vm_object_page_noreuse(vm_object_t object, vm_pindex_t start, vm_pindex_t end) 2098 { 2099 vm_page_t p, next; 2100 2101 VM_OBJECT_ASSERT_LOCKED(object); 2102 KASSERT((object->flags & (OBJ_FICTITIOUS | OBJ_UNMANAGED)) == 0, 2103 ("vm_object_page_noreuse: illegal object %p", object)); 2104 if (object->resident_page_count == 0) 2105 return; 2106 p = vm_page_find_least(object, start); 2107 2108 /* 2109 * Here, the variable "p" is either (1) the page with the least pindex 2110 * greater than or equal to the parameter "start" or (2) NULL. 2111 */ 2112 for (; p != NULL && (p->pindex < end || end == 0); p = next) { 2113 next = TAILQ_NEXT(p, listq); 2114 vm_page_deactivate_noreuse(p); 2115 } 2116 } 2117 2118 /* 2119 * Populate the specified range of the object with valid pages. Returns 2120 * TRUE if the range is successfully populated and FALSE otherwise. 2121 * 2122 * Note: This function should be optimized to pass a larger array of 2123 * pages to vm_pager_get_pages() before it is applied to a non- 2124 * OBJT_DEVICE object. 2125 * 2126 * The object must be locked. 2127 */ 2128 boolean_t 2129 vm_object_populate(vm_object_t object, vm_pindex_t start, vm_pindex_t end) 2130 { 2131 vm_page_t m; 2132 vm_pindex_t pindex; 2133 int rv; 2134 2135 VM_OBJECT_ASSERT_WLOCKED(object); 2136 for (pindex = start; pindex < end; pindex++) { 2137 rv = vm_page_grab_valid(&m, object, pindex, VM_ALLOC_NORMAL); 2138 if (rv != VM_PAGER_OK) 2139 break; 2140 2141 /* 2142 * Keep "m" busy because a subsequent iteration may unlock 2143 * the object. 2144 */ 2145 } 2146 if (pindex > start) { 2147 m = vm_page_lookup(object, start); 2148 while (m != NULL && m->pindex < pindex) { 2149 vm_page_xunbusy(m); 2150 m = TAILQ_NEXT(m, listq); 2151 } 2152 } 2153 return (pindex == end); 2154 } 2155 2156 /* 2157 * Routine: vm_object_coalesce 2158 * Function: Coalesces two objects backing up adjoining 2159 * regions of memory into a single object. 2160 * 2161 * returns TRUE if objects were combined. 2162 * 2163 * NOTE: Only works at the moment if the second object is NULL - 2164 * if it's not, which object do we lock first? 2165 * 2166 * Parameters: 2167 * prev_object First object to coalesce 2168 * prev_offset Offset into prev_object 2169 * prev_size Size of reference to prev_object 2170 * next_size Size of reference to the second object 2171 * reserved Indicator that extension region has 2172 * swap accounted for 2173 * 2174 * Conditions: 2175 * The object must *not* be locked. 2176 */ 2177 boolean_t 2178 vm_object_coalesce(vm_object_t prev_object, vm_ooffset_t prev_offset, 2179 vm_size_t prev_size, vm_size_t next_size, boolean_t reserved) 2180 { 2181 vm_pindex_t next_pindex; 2182 2183 if (prev_object == NULL) 2184 return (TRUE); 2185 if ((prev_object->flags & OBJ_ANON) == 0) 2186 return (FALSE); 2187 2188 VM_OBJECT_WLOCK(prev_object); 2189 /* 2190 * Try to collapse the object first. 2191 */ 2192 vm_object_collapse(prev_object); 2193 2194 /* 2195 * Can't coalesce if: . more than one reference . paged out . shadows 2196 * another object . has a copy elsewhere (any of which mean that the 2197 * pages not mapped to prev_entry may be in use anyway) 2198 */ 2199 if (prev_object->backing_object != NULL) { 2200 VM_OBJECT_WUNLOCK(prev_object); 2201 return (FALSE); 2202 } 2203 2204 prev_size >>= PAGE_SHIFT; 2205 next_size >>= PAGE_SHIFT; 2206 next_pindex = OFF_TO_IDX(prev_offset) + prev_size; 2207 2208 if (prev_object->ref_count > 1 && 2209 prev_object->size != next_pindex && 2210 (prev_object->flags & OBJ_ONEMAPPING) == 0) { 2211 VM_OBJECT_WUNLOCK(prev_object); 2212 return (FALSE); 2213 } 2214 2215 /* 2216 * Account for the charge. 2217 */ 2218 if (prev_object->cred != NULL) { 2219 /* 2220 * If prev_object was charged, then this mapping, 2221 * although not charged now, may become writable 2222 * later. Non-NULL cred in the object would prevent 2223 * swap reservation during enabling of the write 2224 * access, so reserve swap now. Failed reservation 2225 * cause allocation of the separate object for the map 2226 * entry, and swap reservation for this entry is 2227 * managed in appropriate time. 2228 */ 2229 if (!reserved && !swap_reserve_by_cred(ptoa(next_size), 2230 prev_object->cred)) { 2231 VM_OBJECT_WUNLOCK(prev_object); 2232 return (FALSE); 2233 } 2234 prev_object->charge += ptoa(next_size); 2235 } 2236 2237 /* 2238 * Remove any pages that may still be in the object from a previous 2239 * deallocation. 2240 */ 2241 if (next_pindex < prev_object->size) { 2242 vm_object_page_remove(prev_object, next_pindex, next_pindex + 2243 next_size, 0); 2244 #if 0 2245 if (prev_object->cred != NULL) { 2246 KASSERT(prev_object->charge >= 2247 ptoa(prev_object->size - next_pindex), 2248 ("object %p overcharged 1 %jx %jx", prev_object, 2249 (uintmax_t)next_pindex, (uintmax_t)next_size)); 2250 prev_object->charge -= ptoa(prev_object->size - 2251 next_pindex); 2252 } 2253 #endif 2254 } 2255 2256 /* 2257 * Extend the object if necessary. 2258 */ 2259 if (next_pindex + next_size > prev_object->size) 2260 prev_object->size = next_pindex + next_size; 2261 2262 VM_OBJECT_WUNLOCK(prev_object); 2263 return (TRUE); 2264 } 2265 2266 /* 2267 * Fill in the m_dst array with up to *rbehind optional pages before m_src[0] 2268 * and up to *rahead optional pages after m_src[count - 1]. In both cases, stop 2269 * the filling-in short on encountering a cached page, an object boundary limit, 2270 * or an allocation error. Update *rbehind and *rahead to indicate the number 2271 * of pages allocated. Copy elements of m_src into array elements from 2272 * m_dst[*rbehind] to m_dst[*rbehind + count -1]. 2273 */ 2274 void 2275 vm_object_prepare_buf_pages(vm_object_t object, vm_page_t *ma_dst, int count, 2276 int *rbehind, int *rahead, vm_page_t *ma_src) 2277 { 2278 struct pctrie_iter pages; 2279 vm_pindex_t pindex; 2280 vm_page_t m, mpred, msucc; 2281 2282 vm_page_iter_init(&pages, object); 2283 VM_OBJECT_ASSERT_LOCKED(object); 2284 if (*rbehind != 0) { 2285 m = ma_src[0]; 2286 pindex = m->pindex; 2287 mpred = vm_radix_iter_lookup_lt(&pages, pindex); 2288 *rbehind = MIN(*rbehind, 2289 pindex - (mpred != NULL ? mpred->pindex + 1 : 0)); 2290 /* Stepping backward from pindex, mpred doesn't change. */ 2291 for (int i = 0; i < *rbehind; i++) { 2292 m = vm_page_alloc_after(object, &pages, pindex - i - 1, 2293 VM_ALLOC_NORMAL, mpred); 2294 if (m == NULL) { 2295 /* Shift the array. */ 2296 for (int j = 0; j < i; j++) 2297 ma_dst[j] = ma_dst[j + *rbehind - i]; 2298 *rbehind = i; 2299 *rahead = 0; 2300 break; 2301 } 2302 ma_dst[*rbehind - i - 1] = m; 2303 } 2304 } 2305 for (int i = 0; i < count; i++) 2306 ma_dst[*rbehind + i] = ma_src[i]; 2307 if (*rahead != 0) { 2308 m = ma_src[count - 1]; 2309 pindex = m->pindex + 1; 2310 msucc = vm_radix_iter_lookup_ge(&pages, pindex); 2311 *rahead = MIN(*rahead, 2312 (msucc != NULL ? msucc->pindex : object->size) - pindex); 2313 mpred = m; 2314 for (int i = 0; i < *rahead; i++) { 2315 m = vm_page_alloc_after(object, &pages, pindex + i, 2316 VM_ALLOC_NORMAL, mpred); 2317 if (m == NULL) { 2318 *rahead = i; 2319 break; 2320 } 2321 ma_dst[*rbehind + count + i] = mpred = m; 2322 } 2323 } 2324 } 2325 2326 void 2327 vm_object_set_writeable_dirty_(vm_object_t object) 2328 { 2329 atomic_add_int(&object->generation, 1); 2330 } 2331 2332 bool 2333 vm_object_mightbedirty_(vm_object_t object) 2334 { 2335 return (object->generation != object->cleangeneration); 2336 } 2337 2338 /* 2339 * vm_object_unwire: 2340 * 2341 * For each page offset within the specified range of the given object, 2342 * find the highest-level page in the shadow chain and unwire it. A page 2343 * must exist at every page offset, and the highest-level page must be 2344 * wired. 2345 */ 2346 void 2347 vm_object_unwire(vm_object_t object, vm_ooffset_t offset, vm_size_t length, 2348 uint8_t queue) 2349 { 2350 vm_object_t tobject, t1object; 2351 vm_page_t m, tm; 2352 vm_pindex_t end_pindex, pindex, tpindex; 2353 int depth, locked_depth; 2354 2355 KASSERT((offset & PAGE_MASK) == 0, 2356 ("vm_object_unwire: offset is not page aligned")); 2357 KASSERT((length & PAGE_MASK) == 0, 2358 ("vm_object_unwire: length is not a multiple of PAGE_SIZE")); 2359 /* The wired count of a fictitious page never changes. */ 2360 if ((object->flags & OBJ_FICTITIOUS) != 0) 2361 return; 2362 pindex = OFF_TO_IDX(offset); 2363 end_pindex = pindex + atop(length); 2364 again: 2365 locked_depth = 1; 2366 VM_OBJECT_RLOCK(object); 2367 m = vm_page_find_least(object, pindex); 2368 while (pindex < end_pindex) { 2369 if (m == NULL || pindex < m->pindex) { 2370 /* 2371 * The first object in the shadow chain doesn't 2372 * contain a page at the current index. Therefore, 2373 * the page must exist in a backing object. 2374 */ 2375 tobject = object; 2376 tpindex = pindex; 2377 depth = 0; 2378 do { 2379 tpindex += 2380 OFF_TO_IDX(tobject->backing_object_offset); 2381 tobject = tobject->backing_object; 2382 KASSERT(tobject != NULL, 2383 ("vm_object_unwire: missing page")); 2384 if ((tobject->flags & OBJ_FICTITIOUS) != 0) 2385 goto next_page; 2386 depth++; 2387 if (depth == locked_depth) { 2388 locked_depth++; 2389 VM_OBJECT_RLOCK(tobject); 2390 } 2391 } while ((tm = vm_page_lookup(tobject, tpindex)) == 2392 NULL); 2393 } else { 2394 tm = m; 2395 m = TAILQ_NEXT(m, listq); 2396 } 2397 if (vm_page_trysbusy(tm) == 0) { 2398 for (tobject = object; locked_depth >= 1; 2399 locked_depth--) { 2400 t1object = tobject->backing_object; 2401 if (tm->object != tobject) 2402 VM_OBJECT_RUNLOCK(tobject); 2403 tobject = t1object; 2404 } 2405 tobject = tm->object; 2406 if (!vm_page_busy_sleep(tm, "unwbo", 2407 VM_ALLOC_IGN_SBUSY)) 2408 VM_OBJECT_RUNLOCK(tobject); 2409 goto again; 2410 } 2411 vm_page_unwire(tm, queue); 2412 vm_page_sunbusy(tm); 2413 next_page: 2414 pindex++; 2415 } 2416 /* Release the accumulated object locks. */ 2417 for (tobject = object; locked_depth >= 1; locked_depth--) { 2418 t1object = tobject->backing_object; 2419 VM_OBJECT_RUNLOCK(tobject); 2420 tobject = t1object; 2421 } 2422 } 2423 2424 /* 2425 * Return the vnode for the given object, or NULL if none exists. 2426 * For tmpfs objects, the function may return NULL if there is 2427 * no vnode allocated at the time of the call. 2428 */ 2429 struct vnode * 2430 vm_object_vnode(vm_object_t object) 2431 { 2432 struct vnode *vp; 2433 2434 VM_OBJECT_ASSERT_LOCKED(object); 2435 vm_pager_getvp(object, &vp, NULL); 2436 return (vp); 2437 } 2438 2439 /* 2440 * Busy the vm object. This prevents new pages belonging to the object from 2441 * becoming busy. Existing pages persist as busy. Callers are responsible 2442 * for checking page state before proceeding. 2443 */ 2444 void 2445 vm_object_busy(vm_object_t obj) 2446 { 2447 2448 VM_OBJECT_ASSERT_LOCKED(obj); 2449 2450 blockcount_acquire(&obj->busy, 1); 2451 /* The fence is required to order loads of page busy. */ 2452 atomic_thread_fence_acq_rel(); 2453 } 2454 2455 void 2456 vm_object_unbusy(vm_object_t obj) 2457 { 2458 2459 blockcount_release(&obj->busy, 1); 2460 } 2461 2462 void 2463 vm_object_busy_wait(vm_object_t obj, const char *wmesg) 2464 { 2465 2466 VM_OBJECT_ASSERT_UNLOCKED(obj); 2467 2468 (void)blockcount_sleep(&obj->busy, NULL, wmesg, PVM); 2469 } 2470 2471 /* 2472 * This function aims to determine if the object is mapped, 2473 * specifically, if it is referenced by a vm_map_entry. Because 2474 * objects occasionally acquire transient references that do not 2475 * represent a mapping, the method used here is inexact. However, it 2476 * has very low overhead and is good enough for the advisory 2477 * vm.vmtotal sysctl. 2478 */ 2479 bool 2480 vm_object_is_active(vm_object_t obj) 2481 { 2482 2483 return (obj->ref_count > atomic_load_int(&obj->shadow_count)); 2484 } 2485 2486 static int 2487 vm_object_list_handler(struct sysctl_req *req, bool swap_only) 2488 { 2489 struct kinfo_vmobject *kvo; 2490 char *fullpath, *freepath; 2491 struct vnode *vp; 2492 struct vattr va; 2493 vm_object_t obj; 2494 vm_page_t m; 2495 u_long sp; 2496 int count, error; 2497 key_t key; 2498 unsigned short seq; 2499 bool want_path; 2500 2501 if (req->oldptr == NULL) { 2502 /* 2503 * If an old buffer has not been provided, generate an 2504 * estimate of the space needed for a subsequent call. 2505 */ 2506 mtx_lock(&vm_object_list_mtx); 2507 count = 0; 2508 TAILQ_FOREACH(obj, &vm_object_list, object_list) { 2509 if (obj->type == OBJT_DEAD) 2510 continue; 2511 count++; 2512 } 2513 mtx_unlock(&vm_object_list_mtx); 2514 return (SYSCTL_OUT(req, NULL, sizeof(struct kinfo_vmobject) * 2515 count * 11 / 10)); 2516 } 2517 2518 want_path = !(swap_only || jailed(curthread->td_ucred)); 2519 kvo = malloc(sizeof(*kvo), M_TEMP, M_WAITOK | M_ZERO); 2520 error = 0; 2521 2522 /* 2523 * VM objects are type stable and are never removed from the 2524 * list once added. This allows us to safely read obj->object_list 2525 * after reacquiring the VM object lock. 2526 */ 2527 mtx_lock(&vm_object_list_mtx); 2528 TAILQ_FOREACH(obj, &vm_object_list, object_list) { 2529 if (obj->type == OBJT_DEAD || 2530 (swap_only && (obj->flags & (OBJ_ANON | OBJ_SWAP)) == 0)) 2531 continue; 2532 VM_OBJECT_RLOCK(obj); 2533 if (obj->type == OBJT_DEAD || 2534 (swap_only && (obj->flags & (OBJ_ANON | OBJ_SWAP)) == 0)) { 2535 VM_OBJECT_RUNLOCK(obj); 2536 continue; 2537 } 2538 mtx_unlock(&vm_object_list_mtx); 2539 kvo->kvo_size = ptoa(obj->size); 2540 kvo->kvo_resident = obj->resident_page_count; 2541 kvo->kvo_ref_count = obj->ref_count; 2542 kvo->kvo_shadow_count = atomic_load_int(&obj->shadow_count); 2543 kvo->kvo_memattr = obj->memattr; 2544 kvo->kvo_active = 0; 2545 kvo->kvo_inactive = 0; 2546 kvo->kvo_flags = 0; 2547 if (!swap_only) { 2548 TAILQ_FOREACH(m, &obj->memq, listq) { 2549 /* 2550 * A page may belong to the object but be 2551 * dequeued and set to PQ_NONE while the 2552 * object lock is not held. This makes the 2553 * reads of m->queue below racy, and we do not 2554 * count pages set to PQ_NONE. However, this 2555 * sysctl is only meant to give an 2556 * approximation of the system anyway. 2557 */ 2558 if (vm_page_active(m)) 2559 kvo->kvo_active++; 2560 else if (vm_page_inactive(m)) 2561 kvo->kvo_inactive++; 2562 else if (vm_page_in_laundry(m)) 2563 kvo->kvo_laundry++; 2564 } 2565 } 2566 2567 kvo->kvo_vn_fileid = 0; 2568 kvo->kvo_vn_fsid = 0; 2569 kvo->kvo_vn_fsid_freebsd11 = 0; 2570 freepath = NULL; 2571 fullpath = ""; 2572 vp = NULL; 2573 kvo->kvo_type = vm_object_kvme_type(obj, want_path ? &vp : 2574 NULL); 2575 if (vp != NULL) { 2576 vref(vp); 2577 } else if ((obj->flags & OBJ_ANON) != 0) { 2578 MPASS(kvo->kvo_type == KVME_TYPE_SWAP); 2579 kvo->kvo_me = (uintptr_t)obj; 2580 /* tmpfs objs are reported as vnodes */ 2581 kvo->kvo_backing_obj = (uintptr_t)obj->backing_object; 2582 sp = swap_pager_swapped_pages(obj); 2583 kvo->kvo_swapped = sp > UINT32_MAX ? UINT32_MAX : sp; 2584 } 2585 if (obj->type == OBJT_DEVICE || obj->type == OBJT_MGTDEVICE) { 2586 cdev_pager_get_path(obj, kvo->kvo_path, 2587 sizeof(kvo->kvo_path)); 2588 } 2589 VM_OBJECT_RUNLOCK(obj); 2590 if ((obj->flags & OBJ_SYSVSHM) != 0) { 2591 kvo->kvo_flags |= KVMO_FLAG_SYSVSHM; 2592 shmobjinfo(obj, &key, &seq); 2593 kvo->kvo_vn_fileid = key; 2594 kvo->kvo_vn_fsid_freebsd11 = seq; 2595 } 2596 if ((obj->flags & OBJ_POSIXSHM) != 0) { 2597 kvo->kvo_flags |= KVMO_FLAG_POSIXSHM; 2598 shm_get_path(obj, kvo->kvo_path, 2599 sizeof(kvo->kvo_path)); 2600 } 2601 if (vp != NULL) { 2602 vn_fullpath(vp, &fullpath, &freepath); 2603 vn_lock(vp, LK_SHARED | LK_RETRY); 2604 if (VOP_GETATTR(vp, &va, curthread->td_ucred) == 0) { 2605 kvo->kvo_vn_fileid = va.va_fileid; 2606 kvo->kvo_vn_fsid = va.va_fsid; 2607 kvo->kvo_vn_fsid_freebsd11 = va.va_fsid; 2608 /* truncate */ 2609 } 2610 vput(vp); 2611 strlcpy(kvo->kvo_path, fullpath, sizeof(kvo->kvo_path)); 2612 free(freepath, M_TEMP); 2613 } 2614 2615 /* Pack record size down */ 2616 kvo->kvo_structsize = offsetof(struct kinfo_vmobject, kvo_path) 2617 + strlen(kvo->kvo_path) + 1; 2618 kvo->kvo_structsize = roundup(kvo->kvo_structsize, 2619 sizeof(uint64_t)); 2620 error = SYSCTL_OUT(req, kvo, kvo->kvo_structsize); 2621 maybe_yield(); 2622 mtx_lock(&vm_object_list_mtx); 2623 if (error) 2624 break; 2625 } 2626 mtx_unlock(&vm_object_list_mtx); 2627 free(kvo, M_TEMP); 2628 return (error); 2629 } 2630 2631 static int 2632 sysctl_vm_object_list(SYSCTL_HANDLER_ARGS) 2633 { 2634 return (vm_object_list_handler(req, false)); 2635 } 2636 2637 SYSCTL_PROC(_vm, OID_AUTO, objects, CTLTYPE_STRUCT | CTLFLAG_RW | CTLFLAG_SKIP | 2638 CTLFLAG_MPSAFE, NULL, 0, sysctl_vm_object_list, "S,kinfo_vmobject", 2639 "List of VM objects"); 2640 2641 static int 2642 sysctl_vm_object_list_swap(SYSCTL_HANDLER_ARGS) 2643 { 2644 return (vm_object_list_handler(req, true)); 2645 } 2646 2647 /* 2648 * This sysctl returns list of the anonymous or swap objects. Intent 2649 * is to provide stripped optimized list useful to analyze swap use. 2650 * Since technically non-swap (default) objects participate in the 2651 * shadow chains, and are converted to swap type as needed by swap 2652 * pager, we must report them. 2653 */ 2654 SYSCTL_PROC(_vm, OID_AUTO, swap_objects, 2655 CTLTYPE_STRUCT | CTLFLAG_RW | CTLFLAG_SKIP | CTLFLAG_MPSAFE, NULL, 0, 2656 sysctl_vm_object_list_swap, "S,kinfo_vmobject", 2657 "List of swap VM objects"); 2658 2659 #include "opt_ddb.h" 2660 #ifdef DDB 2661 #include <sys/kernel.h> 2662 2663 #include <sys/cons.h> 2664 2665 #include <ddb/ddb.h> 2666 2667 static int 2668 _vm_object_in_map(vm_map_t map, vm_object_t object, vm_map_entry_t entry) 2669 { 2670 vm_map_t tmpm; 2671 vm_map_entry_t tmpe; 2672 vm_object_t obj; 2673 2674 if (map == 0) 2675 return 0; 2676 2677 if (entry == 0) { 2678 VM_MAP_ENTRY_FOREACH(tmpe, map) { 2679 if (_vm_object_in_map(map, object, tmpe)) { 2680 return 1; 2681 } 2682 } 2683 } else if (entry->eflags & MAP_ENTRY_IS_SUB_MAP) { 2684 tmpm = entry->object.sub_map; 2685 VM_MAP_ENTRY_FOREACH(tmpe, tmpm) { 2686 if (_vm_object_in_map(tmpm, object, tmpe)) { 2687 return 1; 2688 } 2689 } 2690 } else if ((obj = entry->object.vm_object) != NULL) { 2691 for (; obj; obj = obj->backing_object) 2692 if (obj == object) { 2693 return 1; 2694 } 2695 } 2696 return 0; 2697 } 2698 2699 static int 2700 vm_object_in_map(vm_object_t object) 2701 { 2702 struct proc *p; 2703 2704 /* sx_slock(&allproc_lock); */ 2705 FOREACH_PROC_IN_SYSTEM(p) { 2706 if (!p->p_vmspace /* || (p->p_flag & (P_SYSTEM|P_WEXIT)) */) 2707 continue; 2708 if (_vm_object_in_map(&p->p_vmspace->vm_map, object, 0)) { 2709 /* sx_sunlock(&allproc_lock); */ 2710 return 1; 2711 } 2712 } 2713 /* sx_sunlock(&allproc_lock); */ 2714 if (_vm_object_in_map(kernel_map, object, 0)) 2715 return 1; 2716 return 0; 2717 } 2718 2719 DB_SHOW_COMMAND_FLAGS(vmochk, vm_object_check, DB_CMD_MEMSAFE) 2720 { 2721 vm_object_t object; 2722 2723 /* 2724 * make sure that internal objs are in a map somewhere 2725 * and none have zero ref counts. 2726 */ 2727 TAILQ_FOREACH(object, &vm_object_list, object_list) { 2728 if ((object->flags & OBJ_ANON) != 0) { 2729 if (object->ref_count == 0) { 2730 db_printf( 2731 "vmochk: internal obj has zero ref count: %lu\n", 2732 (u_long)object->size); 2733 } 2734 if (!vm_object_in_map(object)) { 2735 db_printf( 2736 "vmochk: internal obj is not in a map: " 2737 "ref: %d, size: %lu: 0x%lx, backing_object: %p\n", 2738 object->ref_count, (u_long)object->size, 2739 (u_long)object->size, 2740 (void *)object->backing_object); 2741 } 2742 } 2743 if (db_pager_quit) 2744 return; 2745 } 2746 } 2747 2748 /* 2749 * vm_object_print: [ debug ] 2750 */ 2751 DB_SHOW_COMMAND(object, vm_object_print_static) 2752 { 2753 /* XXX convert args. */ 2754 vm_object_t object = (vm_object_t)addr; 2755 boolean_t full = have_addr; 2756 2757 vm_page_t p; 2758 2759 /* XXX count is an (unused) arg. Avoid shadowing it. */ 2760 #define count was_count 2761 2762 int count; 2763 2764 if (object == NULL) 2765 return; 2766 2767 db_iprintf("Object %p: type=%d, size=0x%jx, res=%d, ref=%d, flags=0x%x", 2768 object, (int)object->type, (uintmax_t)object->size, 2769 object->resident_page_count, object->ref_count, object->flags); 2770 db_iprintf(" ruid %d charge %jx\n", 2771 object->cred ? object->cred->cr_ruid : -1, 2772 (uintmax_t)object->charge); 2773 db_iprintf(" sref=%d, backing_object(%d)=(%p)+0x%jx\n", 2774 atomic_load_int(&object->shadow_count), 2775 object->backing_object ? object->backing_object->ref_count : 0, 2776 object->backing_object, (uintmax_t)object->backing_object_offset); 2777 2778 if (!full) 2779 return; 2780 2781 db_indent += 2; 2782 count = 0; 2783 TAILQ_FOREACH(p, &object->memq, listq) { 2784 if (count == 0) 2785 db_iprintf("memory:="); 2786 else if (count == 6) { 2787 db_printf("\n"); 2788 db_iprintf(" ..."); 2789 count = 0; 2790 } else 2791 db_printf(","); 2792 count++; 2793 2794 db_printf("(off=0x%jx,page=0x%jx)", 2795 (uintmax_t)p->pindex, (uintmax_t)VM_PAGE_TO_PHYS(p)); 2796 2797 if (db_pager_quit) 2798 break; 2799 } 2800 if (count != 0) 2801 db_printf("\n"); 2802 db_indent -= 2; 2803 } 2804 2805 /* XXX. */ 2806 #undef count 2807 2808 /* XXX need this non-static entry for calling from vm_map_print. */ 2809 void 2810 vm_object_print( 2811 /* db_expr_t */ long addr, 2812 boolean_t have_addr, 2813 /* db_expr_t */ long count, 2814 char *modif) 2815 { 2816 vm_object_print_static(addr, have_addr, count, modif); 2817 } 2818 2819 DB_SHOW_COMMAND_FLAGS(vmopag, vm_object_print_pages, DB_CMD_MEMSAFE) 2820 { 2821 vm_object_t object; 2822 vm_pindex_t fidx; 2823 vm_paddr_t pa; 2824 vm_page_t m, prev_m; 2825 int rcount; 2826 2827 TAILQ_FOREACH(object, &vm_object_list, object_list) { 2828 db_printf("new object: %p\n", (void *)object); 2829 if (db_pager_quit) 2830 return; 2831 2832 rcount = 0; 2833 fidx = 0; 2834 pa = -1; 2835 TAILQ_FOREACH(m, &object->memq, listq) { 2836 if ((prev_m = TAILQ_PREV(m, pglist, listq)) != NULL && 2837 prev_m->pindex + 1 != m->pindex) { 2838 if (rcount) { 2839 db_printf(" index(%ld)run(%d)pa(0x%lx)\n", 2840 (long)fidx, rcount, (long)pa); 2841 if (db_pager_quit) 2842 return; 2843 rcount = 0; 2844 } 2845 } 2846 if (rcount && 2847 (VM_PAGE_TO_PHYS(m) == pa + rcount * PAGE_SIZE)) { 2848 ++rcount; 2849 continue; 2850 } 2851 if (rcount) { 2852 db_printf(" index(%ld)run(%d)pa(0x%lx)\n", 2853 (long)fidx, rcount, (long)pa); 2854 if (db_pager_quit) 2855 return; 2856 } 2857 fidx = m->pindex; 2858 pa = VM_PAGE_TO_PHYS(m); 2859 rcount = 1; 2860 } 2861 if (rcount) { 2862 db_printf(" index(%ld)run(%d)pa(0x%lx)\n", 2863 (long)fidx, rcount, (long)pa); 2864 if (db_pager_quit) 2865 return; 2866 } 2867 } 2868 } 2869 #endif /* DDB */ 2870