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