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(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 struct pctrie_iter pages; 1036 vm_page_t np, p; 1037 vm_pindex_t pi, tend, tstart; 1038 int curgeneration, n, pagerflags; 1039 boolean_t eio, res, allclean; 1040 1041 VM_OBJECT_ASSERT_WLOCKED(object); 1042 1043 if (!vm_object_mightbedirty(object) || object->resident_page_count == 0) 1044 return (TRUE); 1045 1046 pagerflags = (flags & (OBJPC_SYNC | OBJPC_INVAL)) != 0 ? 1047 VM_PAGER_PUT_SYNC : VM_PAGER_CLUSTER_OK; 1048 pagerflags |= (flags & OBJPC_INVAL) != 0 ? VM_PAGER_PUT_INVAL : 0; 1049 1050 tstart = OFF_TO_IDX(start); 1051 tend = (end == 0) ? object->size : OFF_TO_IDX(end + PAGE_MASK); 1052 allclean = tstart == 0 && tend >= object->size; 1053 res = TRUE; 1054 vm_page_iter_init(&pages, object); 1055 1056 rescan: 1057 curgeneration = object->generation; 1058 1059 for (p = vm_radix_iter_lookup_ge(&pages, tstart); p != NULL; p = np) { 1060 pi = p->pindex; 1061 if (pi >= tend) 1062 break; 1063 if (vm_page_none_valid(p)) { 1064 np = vm_radix_iter_step(&pages); 1065 continue; 1066 } 1067 if (!vm_page_busy_acquire(p, VM_ALLOC_WAITFAIL)) { 1068 pctrie_iter_reset(&pages); 1069 if (object->generation != curgeneration && 1070 (flags & OBJPC_SYNC) != 0) 1071 goto rescan; 1072 np = vm_radix_iter_lookup_ge(&pages, pi); 1073 continue; 1074 } 1075 if (!vm_object_page_remove_write(p, flags, &allclean)) { 1076 np = vm_radix_iter_step(&pages); 1077 vm_page_xunbusy(p); 1078 continue; 1079 } 1080 if (object->type == OBJT_VNODE) { 1081 n = vm_object_page_collect_flush(&pages, p, pagerflags, 1082 flags, &allclean, &eio); 1083 pctrie_iter_reset(&pages); 1084 if (eio) { 1085 res = FALSE; 1086 allclean = FALSE; 1087 } 1088 if (object->generation != curgeneration && 1089 (flags & OBJPC_SYNC) != 0) 1090 goto rescan; 1091 1092 /* 1093 * If the VOP_PUTPAGES() did a truncated write, so 1094 * that even the first page of the run is not fully 1095 * written, vm_pageout_flush() returns 0 as the run 1096 * length. Since the condition that caused truncated 1097 * write may be permanent, e.g. exhausted free space, 1098 * accepting n == 0 would cause an infinite loop. 1099 * 1100 * Forwarding the iterator leaves the unwritten page 1101 * behind, but there is not much we can do there if 1102 * filesystem refuses to write it. 1103 */ 1104 if (n == 0) { 1105 n = 1; 1106 allclean = FALSE; 1107 } 1108 } else { 1109 n = 1; 1110 vm_page_xunbusy(p); 1111 } 1112 np = vm_radix_iter_lookup_ge(&pages, pi + n); 1113 } 1114 #if 0 1115 VOP_FSYNC(vp, (pagerflags & VM_PAGER_PUT_SYNC) ? MNT_WAIT : 0); 1116 #endif 1117 1118 /* 1119 * Leave updating cleangeneration for tmpfs objects to tmpfs 1120 * scan. It needs to update mtime, which happens for other 1121 * filesystems during page writeouts. 1122 */ 1123 if (allclean && object->type == OBJT_VNODE) 1124 object->cleangeneration = curgeneration; 1125 return (res); 1126 } 1127 1128 static int 1129 vm_object_page_collect_flush(struct pctrie_iter *pages, vm_page_t p, 1130 int pagerflags, int flags, boolean_t *allclean, boolean_t *eio) 1131 { 1132 vm_page_t ma[2 * vm_pageout_page_count - 1]; 1133 int base, count, runlen; 1134 1135 vm_page_lock_assert(p, MA_NOTOWNED); 1136 vm_page_assert_xbusied(p); 1137 base = nitems(ma) / 2; 1138 ma[base] = p; 1139 for (count = 1; count < vm_pageout_page_count; count++) { 1140 p = vm_radix_iter_next(pages); 1141 if (p == NULL || vm_page_tryxbusy(p) == 0) 1142 break; 1143 if (!vm_object_page_remove_write(p, flags, allclean)) { 1144 vm_page_xunbusy(p); 1145 break; 1146 } 1147 ma[base + count] = p; 1148 } 1149 1150 pages->index = ma[base]->pindex; 1151 for (; count < vm_pageout_page_count; count++) { 1152 p = vm_radix_iter_prev(pages); 1153 if (p == NULL || vm_page_tryxbusy(p) == 0) 1154 break; 1155 if (!vm_object_page_remove_write(p, flags, allclean)) { 1156 vm_page_xunbusy(p); 1157 break; 1158 } 1159 ma[--base] = p; 1160 } 1161 1162 vm_pageout_flush(&ma[base], count, pagerflags, nitems(ma) / 2 - base, 1163 &runlen, eio); 1164 return (runlen); 1165 } 1166 1167 /* 1168 * Note that there is absolutely no sense in writing out 1169 * anonymous objects, so we track down the vnode object 1170 * to write out. 1171 * We invalidate (remove) all pages from the address space 1172 * for semantic correctness. 1173 * 1174 * If the backing object is a device object with unmanaged pages, then any 1175 * mappings to the specified range of pages must be removed before this 1176 * function is called. 1177 * 1178 * Note: certain anonymous maps, such as MAP_NOSYNC maps, 1179 * may start out with a NULL object. 1180 */ 1181 boolean_t 1182 vm_object_sync(vm_object_t object, vm_ooffset_t offset, vm_size_t size, 1183 boolean_t syncio, boolean_t invalidate) 1184 { 1185 vm_object_t backing_object; 1186 struct vnode *vp; 1187 struct mount *mp; 1188 int error, flags, fsync_after; 1189 boolean_t res; 1190 1191 if (object == NULL) 1192 return (TRUE); 1193 res = TRUE; 1194 error = 0; 1195 VM_OBJECT_WLOCK(object); 1196 while ((backing_object = object->backing_object) != NULL) { 1197 VM_OBJECT_WLOCK(backing_object); 1198 offset += object->backing_object_offset; 1199 VM_OBJECT_WUNLOCK(object); 1200 object = backing_object; 1201 if (object->size < OFF_TO_IDX(offset + size)) 1202 size = IDX_TO_OFF(object->size) - offset; 1203 } 1204 /* 1205 * Flush pages if writing is allowed, invalidate them 1206 * if invalidation requested. Pages undergoing I/O 1207 * will be ignored by vm_object_page_remove(). 1208 * 1209 * We cannot lock the vnode and then wait for paging 1210 * to complete without deadlocking against vm_fault. 1211 * Instead we simply call vm_object_page_remove() and 1212 * allow it to block internally on a page-by-page 1213 * basis when it encounters pages undergoing async 1214 * I/O. 1215 */ 1216 if (object->type == OBJT_VNODE && 1217 vm_object_mightbedirty(object) != 0 && 1218 ((vp = object->handle)->v_vflag & VV_NOSYNC) == 0) { 1219 VM_OBJECT_WUNLOCK(object); 1220 (void)vn_start_write(vp, &mp, V_WAIT); 1221 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY); 1222 if (syncio && !invalidate && offset == 0 && 1223 atop(size) == object->size) { 1224 /* 1225 * If syncing the whole mapping of the file, 1226 * it is faster to schedule all the writes in 1227 * async mode, also allowing the clustering, 1228 * and then wait for i/o to complete. 1229 */ 1230 flags = 0; 1231 fsync_after = TRUE; 1232 } else { 1233 flags = (syncio || invalidate) ? OBJPC_SYNC : 0; 1234 flags |= invalidate ? (OBJPC_SYNC | OBJPC_INVAL) : 0; 1235 fsync_after = FALSE; 1236 } 1237 VM_OBJECT_WLOCK(object); 1238 res = vm_object_page_clean(object, offset, offset + size, 1239 flags); 1240 VM_OBJECT_WUNLOCK(object); 1241 if (fsync_after) { 1242 for (;;) { 1243 error = VOP_FSYNC(vp, MNT_WAIT, curthread); 1244 if (error != ERELOOKUP) 1245 break; 1246 1247 /* 1248 * Allow SU/bufdaemon to handle more 1249 * dependencies in the meantime. 1250 */ 1251 VOP_UNLOCK(vp); 1252 vn_finished_write(mp); 1253 1254 (void)vn_start_write(vp, &mp, V_WAIT); 1255 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY); 1256 } 1257 } 1258 VOP_UNLOCK(vp); 1259 vn_finished_write(mp); 1260 if (error != 0) 1261 res = FALSE; 1262 VM_OBJECT_WLOCK(object); 1263 } 1264 if ((object->type == OBJT_VNODE || 1265 object->type == OBJT_DEVICE) && invalidate) { 1266 if (object->type == OBJT_DEVICE) 1267 /* 1268 * The option OBJPR_NOTMAPPED must be passed here 1269 * because vm_object_page_remove() cannot remove 1270 * unmanaged mappings. 1271 */ 1272 flags = OBJPR_NOTMAPPED; 1273 else if (old_msync) 1274 flags = 0; 1275 else 1276 flags = OBJPR_CLEANONLY; 1277 vm_object_page_remove(object, OFF_TO_IDX(offset), 1278 OFF_TO_IDX(offset + size + PAGE_MASK), flags); 1279 } 1280 VM_OBJECT_WUNLOCK(object); 1281 return (res); 1282 } 1283 1284 /* 1285 * Determine whether the given advice can be applied to the object. Advice is 1286 * not applied to unmanaged pages since they never belong to page queues, and 1287 * since MADV_FREE is destructive, it can apply only to anonymous pages that 1288 * have been mapped at most once. 1289 */ 1290 static bool 1291 vm_object_advice_applies(vm_object_t object, int advice) 1292 { 1293 1294 if ((object->flags & OBJ_UNMANAGED) != 0) 1295 return (false); 1296 if (advice != MADV_FREE) 1297 return (true); 1298 return ((object->flags & (OBJ_ONEMAPPING | OBJ_ANON)) == 1299 (OBJ_ONEMAPPING | OBJ_ANON)); 1300 } 1301 1302 static void 1303 vm_object_madvise_freespace(vm_object_t object, int advice, vm_pindex_t pindex, 1304 vm_size_t size) 1305 { 1306 1307 if (advice == MADV_FREE) 1308 vm_pager_freespace(object, pindex, size); 1309 } 1310 1311 /* 1312 * vm_object_madvise: 1313 * 1314 * Implements the madvise function at the object/page level. 1315 * 1316 * MADV_WILLNEED (any object) 1317 * 1318 * Activate the specified pages if they are resident. 1319 * 1320 * MADV_DONTNEED (any object) 1321 * 1322 * Deactivate the specified pages if they are resident. 1323 * 1324 * MADV_FREE (OBJT_SWAP objects, OBJ_ONEMAPPING only) 1325 * 1326 * Deactivate and clean the specified pages if they are 1327 * resident. This permits the process to reuse the pages 1328 * without faulting or the kernel to reclaim the pages 1329 * without I/O. 1330 */ 1331 void 1332 vm_object_madvise(vm_object_t object, vm_pindex_t pindex, vm_pindex_t end, 1333 int advice) 1334 { 1335 vm_pindex_t tpindex; 1336 vm_object_t backing_object, tobject; 1337 vm_page_t m, tm; 1338 1339 if (object == NULL) 1340 return; 1341 1342 relookup: 1343 VM_OBJECT_WLOCK(object); 1344 if (!vm_object_advice_applies(object, advice)) { 1345 VM_OBJECT_WUNLOCK(object); 1346 return; 1347 } 1348 for (m = vm_page_find_least(object, pindex); pindex < end; pindex++) { 1349 tobject = object; 1350 1351 /* 1352 * If the next page isn't resident in the top-level object, we 1353 * need to search the shadow chain. When applying MADV_FREE, we 1354 * take care to release any swap space used to store 1355 * non-resident pages. 1356 */ 1357 if (m == NULL || pindex < m->pindex) { 1358 /* 1359 * Optimize a common case: if the top-level object has 1360 * no backing object, we can skip over the non-resident 1361 * range in constant time. 1362 */ 1363 if (object->backing_object == NULL) { 1364 tpindex = (m != NULL && m->pindex < end) ? 1365 m->pindex : end; 1366 vm_object_madvise_freespace(object, advice, 1367 pindex, tpindex - pindex); 1368 if ((pindex = tpindex) == end) 1369 break; 1370 goto next_page; 1371 } 1372 1373 tpindex = pindex; 1374 do { 1375 vm_object_madvise_freespace(tobject, advice, 1376 tpindex, 1); 1377 /* 1378 * Prepare to search the next object in the 1379 * chain. 1380 */ 1381 backing_object = tobject->backing_object; 1382 if (backing_object == NULL) 1383 goto next_pindex; 1384 VM_OBJECT_WLOCK(backing_object); 1385 tpindex += 1386 OFF_TO_IDX(tobject->backing_object_offset); 1387 if (tobject != object) 1388 VM_OBJECT_WUNLOCK(tobject); 1389 tobject = backing_object; 1390 if (!vm_object_advice_applies(tobject, advice)) 1391 goto next_pindex; 1392 } while ((tm = vm_page_lookup(tobject, tpindex)) == 1393 NULL); 1394 } else { 1395 next_page: 1396 tm = m; 1397 m = TAILQ_NEXT(m, listq); 1398 } 1399 1400 /* 1401 * If the page is not in a normal state, skip it. The page 1402 * can not be invalidated while the object lock is held. 1403 */ 1404 if (!vm_page_all_valid(tm) || vm_page_wired(tm)) 1405 goto next_pindex; 1406 KASSERT((tm->flags & PG_FICTITIOUS) == 0, 1407 ("vm_object_madvise: page %p is fictitious", tm)); 1408 KASSERT((tm->oflags & VPO_UNMANAGED) == 0, 1409 ("vm_object_madvise: page %p is not managed", tm)); 1410 if (vm_page_tryxbusy(tm) == 0) { 1411 if (object != tobject) 1412 VM_OBJECT_WUNLOCK(object); 1413 if (advice == MADV_WILLNEED) { 1414 /* 1415 * Reference the page before unlocking and 1416 * sleeping so that the page daemon is less 1417 * likely to reclaim it. 1418 */ 1419 vm_page_aflag_set(tm, PGA_REFERENCED); 1420 } 1421 if (!vm_page_busy_sleep(tm, "madvpo", 0)) 1422 VM_OBJECT_WUNLOCK(tobject); 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 1656 TAILQ_FOREACH(m, &new_object->memq, listq) 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 vm_page_t p, next; 2106 2107 VM_OBJECT_ASSERT_LOCKED(object); 2108 KASSERT((object->flags & (OBJ_FICTITIOUS | OBJ_UNMANAGED)) == 0, 2109 ("vm_object_page_noreuse: illegal object %p", object)); 2110 if (object->resident_page_count == 0) 2111 return; 2112 p = vm_page_find_least(object, start); 2113 2114 /* 2115 * Here, the variable "p" is either (1) the page with the least pindex 2116 * greater than or equal to the parameter "start" or (2) NULL. 2117 */ 2118 for (; p != NULL && (p->pindex < end || end == 0); p = next) { 2119 next = TAILQ_NEXT(p, listq); 2120 vm_page_deactivate_noreuse(p); 2121 } 2122 } 2123 2124 /* 2125 * Populate the specified range of the object with valid pages. Returns 2126 * TRUE if the range is successfully populated and FALSE otherwise. 2127 * 2128 * Note: This function should be optimized to pass a larger array of 2129 * pages to vm_pager_get_pages() before it is applied to a non- 2130 * OBJT_DEVICE object. 2131 * 2132 * The object must be locked. 2133 */ 2134 boolean_t 2135 vm_object_populate(vm_object_t object, vm_pindex_t start, vm_pindex_t end) 2136 { 2137 vm_page_t m; 2138 vm_pindex_t pindex; 2139 int rv; 2140 2141 VM_OBJECT_ASSERT_WLOCKED(object); 2142 for (pindex = start; pindex < end; pindex++) { 2143 rv = vm_page_grab_valid(&m, object, pindex, VM_ALLOC_NORMAL); 2144 if (rv != VM_PAGER_OK) 2145 break; 2146 2147 /* 2148 * Keep "m" busy because a subsequent iteration may unlock 2149 * the object. 2150 */ 2151 } 2152 if (pindex > start) { 2153 m = vm_page_lookup(object, start); 2154 while (m != NULL && m->pindex < pindex) { 2155 vm_page_xunbusy(m); 2156 m = TAILQ_NEXT(m, listq); 2157 } 2158 } 2159 return (pindex == end); 2160 } 2161 2162 /* 2163 * Routine: vm_object_coalesce 2164 * Function: Coalesces two objects backing up adjoining 2165 * regions of memory into a single object. 2166 * 2167 * returns TRUE if objects were combined. 2168 * 2169 * NOTE: Only works at the moment if the second object is NULL - 2170 * if it's not, which object do we lock first? 2171 * 2172 * Parameters: 2173 * prev_object First object to coalesce 2174 * prev_offset Offset into prev_object 2175 * prev_size Size of reference to prev_object 2176 * next_size Size of reference to the second object 2177 * reserved Indicator that extension region has 2178 * swap accounted for 2179 * 2180 * Conditions: 2181 * The object must *not* be locked. 2182 */ 2183 boolean_t 2184 vm_object_coalesce(vm_object_t prev_object, vm_ooffset_t prev_offset, 2185 vm_size_t prev_size, vm_size_t next_size, boolean_t reserved) 2186 { 2187 vm_pindex_t next_pindex; 2188 2189 if (prev_object == NULL) 2190 return (TRUE); 2191 if ((prev_object->flags & OBJ_ANON) == 0) 2192 return (FALSE); 2193 2194 VM_OBJECT_WLOCK(prev_object); 2195 /* 2196 * Try to collapse the object first. 2197 */ 2198 vm_object_collapse(prev_object); 2199 2200 /* 2201 * Can't coalesce if: . more than one reference . paged out . shadows 2202 * another object . has a copy elsewhere (any of which mean that the 2203 * pages not mapped to prev_entry may be in use anyway) 2204 */ 2205 if (prev_object->backing_object != NULL) { 2206 VM_OBJECT_WUNLOCK(prev_object); 2207 return (FALSE); 2208 } 2209 2210 prev_size >>= PAGE_SHIFT; 2211 next_size >>= PAGE_SHIFT; 2212 next_pindex = OFF_TO_IDX(prev_offset) + prev_size; 2213 2214 if (prev_object->ref_count > 1 && 2215 prev_object->size != next_pindex && 2216 (prev_object->flags & OBJ_ONEMAPPING) == 0) { 2217 VM_OBJECT_WUNLOCK(prev_object); 2218 return (FALSE); 2219 } 2220 2221 /* 2222 * Account for the charge. 2223 */ 2224 if (prev_object->cred != NULL) { 2225 /* 2226 * If prev_object was charged, then this mapping, 2227 * although not charged now, may become writable 2228 * later. Non-NULL cred in the object would prevent 2229 * swap reservation during enabling of the write 2230 * access, so reserve swap now. Failed reservation 2231 * cause allocation of the separate object for the map 2232 * entry, and swap reservation for this entry is 2233 * managed in appropriate time. 2234 */ 2235 if (!reserved && !swap_reserve_by_cred(ptoa(next_size), 2236 prev_object->cred)) { 2237 VM_OBJECT_WUNLOCK(prev_object); 2238 return (FALSE); 2239 } 2240 prev_object->charge += ptoa(next_size); 2241 } 2242 2243 /* 2244 * Remove any pages that may still be in the object from a previous 2245 * deallocation. 2246 */ 2247 if (next_pindex < prev_object->size) { 2248 vm_object_page_remove(prev_object, next_pindex, next_pindex + 2249 next_size, 0); 2250 #if 0 2251 if (prev_object->cred != NULL) { 2252 KASSERT(prev_object->charge >= 2253 ptoa(prev_object->size - next_pindex), 2254 ("object %p overcharged 1 %jx %jx", prev_object, 2255 (uintmax_t)next_pindex, (uintmax_t)next_size)); 2256 prev_object->charge -= ptoa(prev_object->size - 2257 next_pindex); 2258 } 2259 #endif 2260 } 2261 2262 /* 2263 * Extend the object if necessary. 2264 */ 2265 if (next_pindex + next_size > prev_object->size) 2266 prev_object->size = next_pindex + next_size; 2267 2268 VM_OBJECT_WUNLOCK(prev_object); 2269 return (TRUE); 2270 } 2271 2272 /* 2273 * Fill in the m_dst array with up to *rbehind optional pages before m_src[0] 2274 * and up to *rahead optional pages after m_src[count - 1]. In both cases, stop 2275 * the filling-in short on encountering a cached page, an object boundary limit, 2276 * or an allocation error. Update *rbehind and *rahead to indicate the number 2277 * of pages allocated. Copy elements of m_src into array elements from 2278 * m_dst[*rbehind] to m_dst[*rbehind + count -1]. 2279 */ 2280 void 2281 vm_object_prepare_buf_pages(vm_object_t object, vm_page_t *ma_dst, int count, 2282 int *rbehind, int *rahead, vm_page_t *ma_src) 2283 { 2284 struct pctrie_iter pages; 2285 vm_pindex_t pindex; 2286 vm_page_t m, mpred, msucc; 2287 2288 vm_page_iter_init(&pages, object); 2289 VM_OBJECT_ASSERT_LOCKED(object); 2290 if (*rbehind != 0) { 2291 m = ma_src[0]; 2292 pindex = m->pindex; 2293 mpred = vm_radix_iter_lookup_lt(&pages, pindex); 2294 *rbehind = MIN(*rbehind, 2295 pindex - (mpred != NULL ? mpred->pindex + 1 : 0)); 2296 /* Stepping backward from pindex, mpred doesn't change. */ 2297 for (int i = 0; i < *rbehind; i++) { 2298 m = vm_page_alloc_after(object, &pages, pindex - i - 1, 2299 VM_ALLOC_NORMAL, mpred); 2300 if (m == NULL) { 2301 /* Shift the array. */ 2302 for (int j = 0; j < i; j++) 2303 ma_dst[j] = ma_dst[j + *rbehind - i]; 2304 *rbehind = i; 2305 *rahead = 0; 2306 break; 2307 } 2308 ma_dst[*rbehind - i - 1] = m; 2309 } 2310 } 2311 for (int i = 0; i < count; i++) 2312 ma_dst[*rbehind + i] = ma_src[i]; 2313 if (*rahead != 0) { 2314 m = ma_src[count - 1]; 2315 pindex = m->pindex + 1; 2316 msucc = vm_radix_iter_lookup_ge(&pages, pindex); 2317 *rahead = MIN(*rahead, 2318 (msucc != NULL ? msucc->pindex : object->size) - pindex); 2319 mpred = m; 2320 for (int i = 0; i < *rahead; i++) { 2321 m = vm_page_alloc_after(object, &pages, pindex + i, 2322 VM_ALLOC_NORMAL, mpred); 2323 if (m == NULL) { 2324 *rahead = i; 2325 break; 2326 } 2327 ma_dst[*rbehind + count + i] = mpred = m; 2328 } 2329 } 2330 } 2331 2332 void 2333 vm_object_set_writeable_dirty_(vm_object_t object) 2334 { 2335 atomic_add_int(&object->generation, 1); 2336 } 2337 2338 bool 2339 vm_object_mightbedirty_(vm_object_t object) 2340 { 2341 return (object->generation != object->cleangeneration); 2342 } 2343 2344 /* 2345 * vm_object_unwire: 2346 * 2347 * For each page offset within the specified range of the given object, 2348 * find the highest-level page in the shadow chain and unwire it. A page 2349 * must exist at every page offset, and the highest-level page must be 2350 * wired. 2351 */ 2352 void 2353 vm_object_unwire(vm_object_t object, vm_ooffset_t offset, vm_size_t length, 2354 uint8_t queue) 2355 { 2356 vm_object_t tobject, t1object; 2357 vm_page_t m, tm; 2358 vm_pindex_t end_pindex, pindex, tpindex; 2359 int depth, locked_depth; 2360 2361 KASSERT((offset & PAGE_MASK) == 0, 2362 ("vm_object_unwire: offset is not page aligned")); 2363 KASSERT((length & PAGE_MASK) == 0, 2364 ("vm_object_unwire: length is not a multiple of PAGE_SIZE")); 2365 /* The wired count of a fictitious page never changes. */ 2366 if ((object->flags & OBJ_FICTITIOUS) != 0) 2367 return; 2368 pindex = OFF_TO_IDX(offset); 2369 end_pindex = pindex + atop(length); 2370 again: 2371 locked_depth = 1; 2372 VM_OBJECT_RLOCK(object); 2373 m = vm_page_find_least(object, pindex); 2374 while (pindex < end_pindex) { 2375 if (m == NULL || pindex < m->pindex) { 2376 /* 2377 * The first object in the shadow chain doesn't 2378 * contain a page at the current index. Therefore, 2379 * the page must exist in a backing object. 2380 */ 2381 tobject = object; 2382 tpindex = pindex; 2383 depth = 0; 2384 do { 2385 tpindex += 2386 OFF_TO_IDX(tobject->backing_object_offset); 2387 tobject = tobject->backing_object; 2388 KASSERT(tobject != NULL, 2389 ("vm_object_unwire: missing page")); 2390 if ((tobject->flags & OBJ_FICTITIOUS) != 0) 2391 goto next_page; 2392 depth++; 2393 if (depth == locked_depth) { 2394 locked_depth++; 2395 VM_OBJECT_RLOCK(tobject); 2396 } 2397 } while ((tm = vm_page_lookup(tobject, tpindex)) == 2398 NULL); 2399 } else { 2400 tm = m; 2401 m = TAILQ_NEXT(m, listq); 2402 } 2403 if (vm_page_trysbusy(tm) == 0) { 2404 for (tobject = object; locked_depth >= 1; 2405 locked_depth--) { 2406 t1object = tobject->backing_object; 2407 if (tm->object != tobject) 2408 VM_OBJECT_RUNLOCK(tobject); 2409 tobject = t1object; 2410 } 2411 tobject = tm->object; 2412 if (!vm_page_busy_sleep(tm, "unwbo", 2413 VM_ALLOC_IGN_SBUSY)) 2414 VM_OBJECT_RUNLOCK(tobject); 2415 goto again; 2416 } 2417 vm_page_unwire(tm, queue); 2418 vm_page_sunbusy(tm); 2419 next_page: 2420 pindex++; 2421 } 2422 /* Release the accumulated object locks. */ 2423 for (tobject = object; locked_depth >= 1; locked_depth--) { 2424 t1object = tobject->backing_object; 2425 VM_OBJECT_RUNLOCK(tobject); 2426 tobject = t1object; 2427 } 2428 } 2429 2430 /* 2431 * Return the vnode for the given object, or NULL if none exists. 2432 * For tmpfs objects, the function may return NULL if there is 2433 * no vnode allocated at the time of the call. 2434 */ 2435 struct vnode * 2436 vm_object_vnode(vm_object_t object) 2437 { 2438 struct vnode *vp; 2439 2440 VM_OBJECT_ASSERT_LOCKED(object); 2441 vm_pager_getvp(object, &vp, NULL); 2442 return (vp); 2443 } 2444 2445 /* 2446 * Busy the vm object. This prevents new pages belonging to the object from 2447 * becoming busy. Existing pages persist as busy. Callers are responsible 2448 * for checking page state before proceeding. 2449 */ 2450 void 2451 vm_object_busy(vm_object_t obj) 2452 { 2453 2454 VM_OBJECT_ASSERT_LOCKED(obj); 2455 2456 blockcount_acquire(&obj->busy, 1); 2457 /* The fence is required to order loads of page busy. */ 2458 atomic_thread_fence_acq_rel(); 2459 } 2460 2461 void 2462 vm_object_unbusy(vm_object_t obj) 2463 { 2464 2465 blockcount_release(&obj->busy, 1); 2466 } 2467 2468 void 2469 vm_object_busy_wait(vm_object_t obj, const char *wmesg) 2470 { 2471 2472 VM_OBJECT_ASSERT_UNLOCKED(obj); 2473 2474 (void)blockcount_sleep(&obj->busy, NULL, wmesg, PVM); 2475 } 2476 2477 /* 2478 * This function aims to determine if the object is mapped, 2479 * specifically, if it is referenced by a vm_map_entry. Because 2480 * objects occasionally acquire transient references that do not 2481 * represent a mapping, the method used here is inexact. However, it 2482 * has very low overhead and is good enough for the advisory 2483 * vm.vmtotal sysctl. 2484 */ 2485 bool 2486 vm_object_is_active(vm_object_t obj) 2487 { 2488 2489 return (obj->ref_count > atomic_load_int(&obj->shadow_count)); 2490 } 2491 2492 static int 2493 vm_object_list_handler(struct sysctl_req *req, bool swap_only) 2494 { 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 TAILQ_FOREACH(m, &obj->memq, listq) { 2555 /* 2556 * A page may belong to the object but be 2557 * dequeued and set to PQ_NONE while the 2558 * object lock is not held. This makes the 2559 * reads of m->queue below racy, and we do not 2560 * count pages set to PQ_NONE. However, this 2561 * sysctl is only meant to give an 2562 * approximation of the system anyway. 2563 */ 2564 if (vm_page_active(m)) 2565 kvo->kvo_active++; 2566 else if (vm_page_inactive(m)) 2567 kvo->kvo_inactive++; 2568 else if (vm_page_in_laundry(m)) 2569 kvo->kvo_laundry++; 2570 } 2571 } 2572 2573 kvo->kvo_vn_fileid = 0; 2574 kvo->kvo_vn_fsid = 0; 2575 kvo->kvo_vn_fsid_freebsd11 = 0; 2576 freepath = NULL; 2577 fullpath = ""; 2578 vp = NULL; 2579 kvo->kvo_type = vm_object_kvme_type(obj, want_path ? &vp : 2580 NULL); 2581 if (vp != NULL) { 2582 vref(vp); 2583 } else if ((obj->flags & OBJ_ANON) != 0) { 2584 MPASS(kvo->kvo_type == KVME_TYPE_SWAP); 2585 kvo->kvo_me = (uintptr_t)obj; 2586 /* tmpfs objs are reported as vnodes */ 2587 kvo->kvo_backing_obj = (uintptr_t)obj->backing_object; 2588 sp = swap_pager_swapped_pages(obj); 2589 kvo->kvo_swapped = sp > UINT32_MAX ? UINT32_MAX : sp; 2590 } 2591 if (obj->type == OBJT_DEVICE || obj->type == OBJT_MGTDEVICE) { 2592 cdev_pager_get_path(obj, kvo->kvo_path, 2593 sizeof(kvo->kvo_path)); 2594 } 2595 VM_OBJECT_RUNLOCK(obj); 2596 if ((obj->flags & OBJ_SYSVSHM) != 0) { 2597 kvo->kvo_flags |= KVMO_FLAG_SYSVSHM; 2598 shmobjinfo(obj, &key, &seq); 2599 kvo->kvo_vn_fileid = key; 2600 kvo->kvo_vn_fsid_freebsd11 = seq; 2601 } 2602 if ((obj->flags & OBJ_POSIXSHM) != 0) { 2603 kvo->kvo_flags |= KVMO_FLAG_POSIXSHM; 2604 shm_get_path(obj, kvo->kvo_path, 2605 sizeof(kvo->kvo_path)); 2606 } 2607 if (vp != NULL) { 2608 vn_fullpath(vp, &fullpath, &freepath); 2609 vn_lock(vp, LK_SHARED | LK_RETRY); 2610 if (VOP_GETATTR(vp, &va, curthread->td_ucred) == 0) { 2611 kvo->kvo_vn_fileid = va.va_fileid; 2612 kvo->kvo_vn_fsid = va.va_fsid; 2613 kvo->kvo_vn_fsid_freebsd11 = va.va_fsid; 2614 /* truncate */ 2615 } 2616 vput(vp); 2617 strlcpy(kvo->kvo_path, fullpath, sizeof(kvo->kvo_path)); 2618 free(freepath, M_TEMP); 2619 } 2620 2621 /* Pack record size down */ 2622 kvo->kvo_structsize = offsetof(struct kinfo_vmobject, kvo_path) 2623 + strlen(kvo->kvo_path) + 1; 2624 kvo->kvo_structsize = roundup(kvo->kvo_structsize, 2625 sizeof(uint64_t)); 2626 error = SYSCTL_OUT(req, kvo, kvo->kvo_structsize); 2627 maybe_yield(); 2628 mtx_lock(&vm_object_list_mtx); 2629 if (error) 2630 break; 2631 } 2632 mtx_unlock(&vm_object_list_mtx); 2633 free(kvo, M_TEMP); 2634 return (error); 2635 } 2636 2637 static int 2638 sysctl_vm_object_list(SYSCTL_HANDLER_ARGS) 2639 { 2640 return (vm_object_list_handler(req, false)); 2641 } 2642 2643 SYSCTL_PROC(_vm, OID_AUTO, objects, CTLTYPE_STRUCT | CTLFLAG_RW | CTLFLAG_SKIP | 2644 CTLFLAG_MPSAFE, NULL, 0, sysctl_vm_object_list, "S,kinfo_vmobject", 2645 "List of VM objects"); 2646 2647 static int 2648 sysctl_vm_object_list_swap(SYSCTL_HANDLER_ARGS) 2649 { 2650 return (vm_object_list_handler(req, true)); 2651 } 2652 2653 /* 2654 * This sysctl returns list of the anonymous or swap objects. Intent 2655 * is to provide stripped optimized list useful to analyze swap use. 2656 * Since technically non-swap (default) objects participate in the 2657 * shadow chains, and are converted to swap type as needed by swap 2658 * pager, we must report them. 2659 */ 2660 SYSCTL_PROC(_vm, OID_AUTO, swap_objects, 2661 CTLTYPE_STRUCT | CTLFLAG_RW | CTLFLAG_SKIP | CTLFLAG_MPSAFE, NULL, 0, 2662 sysctl_vm_object_list_swap, "S,kinfo_vmobject", 2663 "List of swap VM objects"); 2664 2665 #include "opt_ddb.h" 2666 #ifdef DDB 2667 #include <sys/kernel.h> 2668 2669 #include <sys/cons.h> 2670 2671 #include <ddb/ddb.h> 2672 2673 static int 2674 _vm_object_in_map(vm_map_t map, vm_object_t object, vm_map_entry_t entry) 2675 { 2676 vm_map_t tmpm; 2677 vm_map_entry_t tmpe; 2678 vm_object_t obj; 2679 2680 if (map == 0) 2681 return 0; 2682 2683 if (entry == 0) { 2684 VM_MAP_ENTRY_FOREACH(tmpe, map) { 2685 if (_vm_object_in_map(map, object, tmpe)) { 2686 return 1; 2687 } 2688 } 2689 } else if (entry->eflags & MAP_ENTRY_IS_SUB_MAP) { 2690 tmpm = entry->object.sub_map; 2691 VM_MAP_ENTRY_FOREACH(tmpe, tmpm) { 2692 if (_vm_object_in_map(tmpm, object, tmpe)) { 2693 return 1; 2694 } 2695 } 2696 } else if ((obj = entry->object.vm_object) != NULL) { 2697 for (; obj; obj = obj->backing_object) 2698 if (obj == object) { 2699 return 1; 2700 } 2701 } 2702 return 0; 2703 } 2704 2705 static int 2706 vm_object_in_map(vm_object_t object) 2707 { 2708 struct proc *p; 2709 2710 /* sx_slock(&allproc_lock); */ 2711 FOREACH_PROC_IN_SYSTEM(p) { 2712 if (!p->p_vmspace /* || (p->p_flag & (P_SYSTEM|P_WEXIT)) */) 2713 continue; 2714 if (_vm_object_in_map(&p->p_vmspace->vm_map, object, 0)) { 2715 /* sx_sunlock(&allproc_lock); */ 2716 return 1; 2717 } 2718 } 2719 /* sx_sunlock(&allproc_lock); */ 2720 if (_vm_object_in_map(kernel_map, object, 0)) 2721 return 1; 2722 return 0; 2723 } 2724 2725 DB_SHOW_COMMAND_FLAGS(vmochk, vm_object_check, DB_CMD_MEMSAFE) 2726 { 2727 vm_object_t object; 2728 2729 /* 2730 * make sure that internal objs are in a map somewhere 2731 * and none have zero ref counts. 2732 */ 2733 TAILQ_FOREACH(object, &vm_object_list, object_list) { 2734 if ((object->flags & OBJ_ANON) != 0) { 2735 if (object->ref_count == 0) { 2736 db_printf( 2737 "vmochk: internal obj has zero ref count: %lu\n", 2738 (u_long)object->size); 2739 } 2740 if (!vm_object_in_map(object)) { 2741 db_printf( 2742 "vmochk: internal obj is not in a map: " 2743 "ref: %d, size: %lu: 0x%lx, backing_object: %p\n", 2744 object->ref_count, (u_long)object->size, 2745 (u_long)object->size, 2746 (void *)object->backing_object); 2747 } 2748 } 2749 if (db_pager_quit) 2750 return; 2751 } 2752 } 2753 2754 /* 2755 * vm_object_print: [ debug ] 2756 */ 2757 DB_SHOW_COMMAND(object, vm_object_print_static) 2758 { 2759 /* XXX convert args. */ 2760 vm_object_t object = (vm_object_t)addr; 2761 boolean_t full = have_addr; 2762 2763 vm_page_t p; 2764 2765 /* XXX count is an (unused) arg. Avoid shadowing it. */ 2766 #define count was_count 2767 2768 int count; 2769 2770 if (object == NULL) 2771 return; 2772 2773 db_iprintf("Object %p: type=%d, size=0x%jx, res=%d, ref=%d, flags=0x%x", 2774 object, (int)object->type, (uintmax_t)object->size, 2775 object->resident_page_count, object->ref_count, object->flags); 2776 db_iprintf(" ruid %d charge %jx\n", 2777 object->cred ? object->cred->cr_ruid : -1, 2778 (uintmax_t)object->charge); 2779 db_iprintf(" sref=%d, backing_object(%d)=(%p)+0x%jx\n", 2780 atomic_load_int(&object->shadow_count), 2781 object->backing_object ? object->backing_object->ref_count : 0, 2782 object->backing_object, (uintmax_t)object->backing_object_offset); 2783 2784 if (!full) 2785 return; 2786 2787 db_indent += 2; 2788 count = 0; 2789 TAILQ_FOREACH(p, &object->memq, listq) { 2790 if (count == 0) 2791 db_iprintf("memory:="); 2792 else if (count == 6) { 2793 db_printf("\n"); 2794 db_iprintf(" ..."); 2795 count = 0; 2796 } else 2797 db_printf(","); 2798 count++; 2799 2800 db_printf("(off=0x%jx,page=0x%jx)", 2801 (uintmax_t)p->pindex, (uintmax_t)VM_PAGE_TO_PHYS(p)); 2802 2803 if (db_pager_quit) 2804 break; 2805 } 2806 if (count != 0) 2807 db_printf("\n"); 2808 db_indent -= 2; 2809 } 2810 2811 /* XXX. */ 2812 #undef count 2813 2814 /* XXX need this non-static entry for calling from vm_map_print. */ 2815 void 2816 vm_object_print( 2817 /* db_expr_t */ long addr, 2818 boolean_t have_addr, 2819 /* db_expr_t */ long count, 2820 char *modif) 2821 { 2822 vm_object_print_static(addr, have_addr, count, modif); 2823 } 2824 2825 DB_SHOW_COMMAND_FLAGS(vmopag, vm_object_print_pages, DB_CMD_MEMSAFE) 2826 { 2827 vm_object_t object; 2828 vm_pindex_t fidx; 2829 vm_paddr_t pa; 2830 vm_page_t m, prev_m; 2831 int rcount; 2832 2833 TAILQ_FOREACH(object, &vm_object_list, object_list) { 2834 db_printf("new object: %p\n", (void *)object); 2835 if (db_pager_quit) 2836 return; 2837 2838 rcount = 0; 2839 fidx = 0; 2840 pa = -1; 2841 TAILQ_FOREACH(m, &object->memq, listq) { 2842 if ((prev_m = TAILQ_PREV(m, pglist, listq)) != NULL && 2843 prev_m->pindex + 1 != m->pindex) { 2844 if (rcount) { 2845 db_printf(" index(%ld)run(%d)pa(0x%lx)\n", 2846 (long)fidx, rcount, (long)pa); 2847 if (db_pager_quit) 2848 return; 2849 rcount = 0; 2850 } 2851 } 2852 if (rcount && 2853 (VM_PAGE_TO_PHYS(m) == pa + rcount * PAGE_SIZE)) { 2854 ++rcount; 2855 continue; 2856 } 2857 if (rcount) { 2858 db_printf(" index(%ld)run(%d)pa(0x%lx)\n", 2859 (long)fidx, rcount, (long)pa); 2860 if (db_pager_quit) 2861 return; 2862 } 2863 fidx = m->pindex; 2864 pa = VM_PAGE_TO_PHYS(m); 2865 rcount = 1; 2866 } 2867 if (rcount) { 2868 db_printf(" index(%ld)run(%d)pa(0x%lx)\n", 2869 (long)fidx, rcount, (long)pa); 2870 if (db_pager_quit) 2871 return; 2872 } 2873 } 2874 } 2875 #endif /* DDB */ 2876