vm_object.c revision 247788
1139776Simp/*- 222521Sdyson * Copyright (c) 1991, 1993 31541Srgrimes * The Regents of the University of California. All rights reserved. 41541Srgrimes * 51541Srgrimes * This code is derived from software contributed to Berkeley by 61541Srgrimes * The Mach Operating System project at Carnegie-Mellon University. 71541Srgrimes * 81541Srgrimes * Redistribution and use in source and binary forms, with or without 91541Srgrimes * modification, are permitted provided that the following conditions 101541Srgrimes * are met: 111541Srgrimes * 1. Redistributions of source code must retain the above copyright 121541Srgrimes * notice, this list of conditions and the following disclaimer. 131541Srgrimes * 2. Redistributions in binary form must reproduce the above copyright 141541Srgrimes * notice, this list of conditions and the following disclaimer in the 151541Srgrimes * documentation and/or other materials provided with the distribution. 161541Srgrimes * 4. Neither the name of the University nor the names of its contributors 171541Srgrimes * may be used to endorse or promote products derived from this software 181541Srgrimes * without specific prior written permission. 191541Srgrimes * 201541Srgrimes * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 211541Srgrimes * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 221541Srgrimes * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 231541Srgrimes * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 241541Srgrimes * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 251541Srgrimes * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 261541Srgrimes * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 271541Srgrimes * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 281541Srgrimes * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 291541Srgrimes * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 301541Srgrimes * SUCH DAMAGE. 311541Srgrimes * 321541Srgrimes * from: @(#)vm_object.c 8.5 (Berkeley) 3/22/94 331541Srgrimes * 3450477Speter * 351541Srgrimes * Copyright (c) 1987, 1990 Carnegie-Mellon University. 361541Srgrimes * All rights reserved. 371541Srgrimes * 381541Srgrimes * Authors: Avadis Tevanian, Jr., Michael Wayne Young 391541Srgrimes * 401541Srgrimes * Permission to use, copy, modify and distribute this software and 411541Srgrimes * its documentation is hereby granted, provided that both the copyright 421541Srgrimes * notice and this permission notice appear in all copies of the 4376166Smarkm * software, derivative works or modified versions, and any portions 442946Swollman * thereof, and that both notices appear in supporting documentation. 4576166Smarkm * 4689316Salfred * CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS" 4776166Smarkm * CONDITION. CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND 4876166Smarkm * FOR ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE. 491541Srgrimes * 501541Srgrimes * Carnegie Mellon requests users of this software to return to 511541Srgrimes * 5276166Smarkm * Software Distribution Coordinator or Software.Distribution@CS.CMU.EDU 5377031Sru * School of Computer Science 541541Srgrimes * Carnegie Mellon University 55151897Srwatson * Pittsburgh PA 15213-3890 5630354Sphk * 57158611Skbyanc * any improvements or extensions that they make and grant Carnegie the 58132902Sphk * rights to redistribute these changes. 59116271Sphk */ 60116271Sphk 61141622Sphk/* 62116271Sphk * Virtual memory object module. 631541Srgrimes */ 64158611Skbyanc 65158611Skbyanc#include <sys/cdefs.h> 66158611Skbyanc__FBSDID("$FreeBSD: head/sys/vm/vm_object.c 247788 2013-03-04 13:10:59Z attilio $"); 67191990Sattilio 68158611Skbyanc#include "opt_vm.h" 69158611Skbyanc 70158611Skbyanc#include <sys/param.h> 71158611Skbyanc#include <sys/systm.h> 72158611Skbyanc#include <sys/lock.h> 731541Srgrimes#include <sys/mman.h> 741541Srgrimes#include <sys/mount.h> 7512143Sphk#include <sys/kernel.h> 76191990Sattilio#include <sys/sysctl.h> 771541Srgrimes#include <sys/mutex.h> 781541Srgrimes#include <sys/proc.h> /* for curproc, pageproc */ 791541Srgrimes#include <sys/socket.h> 801541Srgrimes#include <sys/resourcevar.h> 811541Srgrimes#include <sys/vnode.h> 821541Srgrimes#include <sys/vmmeter.h> 831541Srgrimes#include <sys/sx.h> 841541Srgrimes 85137478Sphk#include <vm/vm.h> 861541Srgrimes#include <vm/vm_param.h> 871541Srgrimes#include <vm/pmap.h> 88184205Sdes#include <vm/vm_map.h> 89111119Simp#include <vm/vm_object.h> 90179288Slulf#include <vm/vm_page.h> 91179288Slulf#include <vm/vm_pageout.h> 92179288Slulf#include <vm/vm_pager.h> 93179288Slulf#include <vm/swap_pager.h> 94179288Slulf#include <vm/vm_kern.h> 95179288Slulf#include <vm/vm_extern.h> 96179288Slulf#include <vm/vm_reserv.h> 97191990Sattilio#include <vm/uma.h> 98179288Slulf 99179288Slulfstatic int old_msync; 100179288SlulfSYSCTL_INT(_vm, OID_AUTO, old_msync, CTLFLAG_RW, &old_msync, 0, 101179288Slulf "Use old (insecure) msync behavior"); 102179288Slulf 1031541Srgrimesstatic int vm_object_page_collect_flush(vm_object_t object, vm_page_t p, 104101308Sjeff int pagerflags, int flags, boolean_t *clearobjflags, 1051541Srgrimes boolean_t *eio); 106179288Slulfstatic boolean_t vm_object_page_remove_write(vm_page_t p, int flags, 1071541Srgrimes boolean_t *clearobjflags); 1081541Srgrimesstatic void vm_object_qcollapse(vm_object_t object); 109179288Slulfstatic void vm_object_vndeallocate(vm_object_t object); 110179288Slulf 111179288Slulf/* 11222521Sdyson * Virtual memory objects maintain the actual data 1131541Srgrimes * associated with allocated virtual memory. A given 114138483Sphk * page of memory exists within exactly one object. 1151541Srgrimes * 1161541Srgrimes * An object is only deallocated when all "references" 1171541Srgrimes * are given up. Only one "reference" to a given 11812143Sphk * region of an object should be writeable. 119191990Sattilio * 1201541Srgrimes * Associated with each object is a list of all resident 1211541Srgrimes * memory pages belonging to that object; this list is 1221541Srgrimes * maintained by the "vm_page" module, and locked by the object's 123179288Slulf * lock. 124179288Slulf * 1251541Srgrimes * Each object also records a "pager" routine which is 1261541Srgrimes * used to retrieve (and store) pages to the proper backing 1271541Srgrimes * storage. In addition, objects may be backed by other 128179288Slulf * objects from which they were virtual-copied. 129179288Slulf * 130179288Slulf * The only items within the object structure which are 131179288Slulf * modified after time of creation are: 132179288Slulf * reference count locked by object's lock 133179288Slulf * pager routine locked by object's lock 1341541Srgrimes * 135179288Slulf */ 1361541Srgrimes 1371541Srgrimesstruct object_q vm_object_list; 1381541Srgrimesstruct mtx vm_object_list_mtx; /* lock for object list and count */ 1391541Srgrimes 1401541Srgrimesstruct vm_object kernel_object_store; 14176688Siedowsestruct vm_object kmem_object_store; 14276688Siedowse 14376688Siedowsestatic SYSCTL_NODE(_vm_stats, OID_AUTO, object, CTLFLAG_RD, 0, 1441541Srgrimes "VM object stats"); 145191990Sattilio 1461541Srgrimesstatic long object_collapses; 1471541SrgrimesSYSCTL_LONG(_vm_stats_object, OID_AUTO, collapses, CTLFLAG_RD, 1481541Srgrimes &object_collapses, 0, "VM object collapses"); 149179288Slulf 150179288Slulfstatic long object_bypasses; 1511541SrgrimesSYSCTL_LONG(_vm_stats_object, OID_AUTO, bypasses, CTLFLAG_RD, 152179288Slulf &object_bypasses, 0, "VM object bypasses"); 153179288Slulf 1541541Srgrimesstatic uma_zone_t obj_zone; 155179288Slulf 156179288Slulfstatic int vm_object_zinit(void *mem, int size, int flags); 1571541Srgrimes 1581541Srgrimes#ifdef INVARIANTS 1591541Srgrimesstatic void vm_object_zdtor(void *mem, int size, void *arg); 1601541Srgrimes 161141622Sphkstatic void 162191990Sattiliovm_object_zdtor(void *mem, int size, void *arg) 1631541Srgrimes{ 164144058Sjeff vm_object_t object; 1651541Srgrimes 1661541Srgrimes object = (vm_object_t)mem; 1671541Srgrimes KASSERT(TAILQ_EMPTY(&object->memq), 1681541Srgrimes ("object %p has resident pages in its memq", object)); 1691541Srgrimes KASSERT(object->root == NULL, 1701541Srgrimes ("object %p has resident pages in its tree", object)); 1711541Srgrimes#if VM_NRESERVLEVEL > 0 1721541Srgrimes KASSERT(LIST_EMPTY(&object->rvq), 173191990Sattilio ("object %p has reservations", 1741541Srgrimes object)); 1751541Srgrimes#endif 1761541Srgrimes KASSERT(object->cache == NULL, 1771541Srgrimes ("object %p has cached pages", 17812143Sphk object)); 179191990Sattilio KASSERT(object->paging_in_progress == 0, 1801541Srgrimes ("object %p paging_in_progress = %d", 1811541Srgrimes object, object->paging_in_progress)); 182191990Sattilio KASSERT(object->resident_page_count == 0, 18383366Sjulian ("object %p resident_page_count = %d", 1841541Srgrimes object, object->resident_page_count)); 1851541Srgrimes KASSERT(object->shadow_count == 0, 1861541Srgrimes ("object %p shadow_count = %d", 1871541Srgrimes object, object->shadow_count)); 1881541Srgrimes} 1891541Srgrimes#endif 190191990Sattilio 191191990Sattiliostatic int 1921541Srgrimesvm_object_zinit(void *mem, int size, int flags) 1931541Srgrimes{ 1941541Srgrimes vm_object_t object; 1951541Srgrimes 1961541Srgrimes object = (vm_object_t)mem; 1971541Srgrimes bzero(&object->mtx, sizeof(object->mtx)); 198125454Sjhb mtx_init(&object->mtx, "vm object", NULL, MTX_DEF | MTX_DUPOK); 199125454Sjhb 200125454Sjhb /* These are true for any object that has been freed */ 20183366Sjulian object->root = NULL; 202168355Srwatson object->paging_in_progress = 0; 2031541Srgrimes object->resident_page_count = 0; 2041541Srgrimes object->shadow_count = 0; 2051541Srgrimes object->cache = NULL; 2061541Srgrimes return (0); 2071541Srgrimes} 2081541Srgrimes 2091541Srgrimesstatic void 2101541Srgrimes_vm_object_allocate(objtype_t type, vm_pindex_t size, vm_object_t object) 2111541Srgrimes{ 2121541Srgrimes 2131541Srgrimes TAILQ_INIT(&object->memq); 2141541Srgrimes LIST_INIT(&object->shadow_head); 215168355Srwatson 2161541Srgrimes object->type = type; 2171541Srgrimes switch (type) { 2181541Srgrimes case OBJT_DEAD: 2191541Srgrimes panic("_vm_object_allocate: can't create OBJT_DEAD"); 2201541Srgrimes case OBJT_DEFAULT: 2211541Srgrimes case OBJT_SWAP: 2221541Srgrimes object->flags = OBJ_ONEMAPPING; 2231541Srgrimes break; 2241541Srgrimes case OBJT_DEVICE: 2251541Srgrimes case OBJT_SG: 2261541Srgrimes object->flags = OBJ_FICTITIOUS | OBJ_UNMANAGED; 2271541Srgrimes break; 22812143Sphk case OBJT_MGTDEVICE: 229158611Skbyanc object->flags = OBJ_FICTITIOUS; 230116271Sphk break; 231132902Sphk case OBJT_PHYS: 232116271Sphk object->flags = OBJ_UNMANAGED; 233116271Sphk break; 234179288Slulf case OBJT_VNODE: 235116271Sphk object->flags = 0; 2361541Srgrimes break; 2372946Swollman default: 23877133Sru panic("_vm_object_allocate: type %d is undefined", type); 239 } 240 object->size = size; 241 object->generation = 1; 242 object->ref_count = 1; 243 object->memattr = VM_MEMATTR_DEFAULT; 244 object->cred = NULL; 245 object->charge = 0; 246 object->handle = NULL; 247 object->backing_object = NULL; 248 object->backing_object_offset = (vm_ooffset_t) 0; 249#if VM_NRESERVLEVEL > 0 250 LIST_INIT(&object->rvq); 251#endif 252 253 mtx_lock(&vm_object_list_mtx); 254 TAILQ_INSERT_TAIL(&vm_object_list, object, object_list); 255 mtx_unlock(&vm_object_list_mtx); 256} 257 258/* 259 * vm_object_init: 260 * 261 * Initialize the VM objects module. 262 */ 263void 264vm_object_init(void) 265{ 266 TAILQ_INIT(&vm_object_list); 267 mtx_init(&vm_object_list_mtx, "vm object_list", NULL, MTX_DEF); 268 269 mtx_init(&kernel_object->mtx, "vm object", "kernel object", MTX_DEF); 270 _vm_object_allocate(OBJT_PHYS, OFF_TO_IDX(VM_MAX_KERNEL_ADDRESS - VM_MIN_KERNEL_ADDRESS), 271 kernel_object); 272#if VM_NRESERVLEVEL > 0 273 kernel_object->flags |= OBJ_COLORED; 274 kernel_object->pg_color = (u_short)atop(VM_MIN_KERNEL_ADDRESS); 275#endif 276 277 mtx_init(&kmem_object->mtx, "vm object", "kmem object", MTX_DEF); 278 _vm_object_allocate(OBJT_PHYS, OFF_TO_IDX(VM_MAX_KERNEL_ADDRESS - VM_MIN_KERNEL_ADDRESS), 279 kmem_object); 280#if VM_NRESERVLEVEL > 0 281 kmem_object->flags |= OBJ_COLORED; 282 kmem_object->pg_color = (u_short)atop(VM_MIN_KERNEL_ADDRESS); 283#endif 284 285 /* 286 * The lock portion of struct vm_object must be type stable due 287 * to vm_pageout_fallback_object_lock locking a vm object 288 * without holding any references to it. 289 */ 290 obj_zone = uma_zcreate("VM OBJECT", sizeof (struct vm_object), NULL, 291#ifdef INVARIANTS 292 vm_object_zdtor, 293#else 294 NULL, 295#endif 296 vm_object_zinit, NULL, UMA_ALIGN_PTR, UMA_ZONE_VM|UMA_ZONE_NOFREE); 297} 298 299void 300vm_object_clear_flag(vm_object_t object, u_short bits) 301{ 302 303 VM_OBJECT_LOCK_ASSERT(object, MA_OWNED); 304 object->flags &= ~bits; 305} 306 307/* 308 * Sets the default memory attribute for the specified object. Pages 309 * that are allocated to this object are by default assigned this memory 310 * attribute. 311 * 312 * Presently, this function must be called before any pages are allocated 313 * to the object. In the future, this requirement may be relaxed for 314 * "default" and "swap" objects. 315 */ 316int 317vm_object_set_memattr(vm_object_t object, vm_memattr_t memattr) 318{ 319 320 VM_OBJECT_LOCK_ASSERT(object, MA_OWNED); 321 switch (object->type) { 322 case OBJT_DEFAULT: 323 case OBJT_DEVICE: 324 case OBJT_MGTDEVICE: 325 case OBJT_PHYS: 326 case OBJT_SG: 327 case OBJT_SWAP: 328 case OBJT_VNODE: 329 if (!TAILQ_EMPTY(&object->memq)) 330 return (KERN_FAILURE); 331 break; 332 case OBJT_DEAD: 333 return (KERN_INVALID_ARGUMENT); 334 default: 335 panic("vm_object_set_memattr: object %p is of undefined type", 336 object); 337 } 338 object->memattr = memattr; 339 return (KERN_SUCCESS); 340} 341 342void 343vm_object_pip_add(vm_object_t object, short i) 344{ 345 346 VM_OBJECT_LOCK_ASSERT(object, MA_OWNED); 347 object->paging_in_progress += i; 348} 349 350void 351vm_object_pip_subtract(vm_object_t object, short i) 352{ 353 354 VM_OBJECT_LOCK_ASSERT(object, MA_OWNED); 355 object->paging_in_progress -= i; 356} 357 358void 359vm_object_pip_wakeup(vm_object_t object) 360{ 361 362 VM_OBJECT_LOCK_ASSERT(object, MA_OWNED); 363 object->paging_in_progress--; 364 if ((object->flags & OBJ_PIPWNT) && object->paging_in_progress == 0) { 365 vm_object_clear_flag(object, OBJ_PIPWNT); 366 wakeup(object); 367 } 368} 369 370void 371vm_object_pip_wakeupn(vm_object_t object, short i) 372{ 373 374 VM_OBJECT_LOCK_ASSERT(object, MA_OWNED); 375 if (i) 376 object->paging_in_progress -= i; 377 if ((object->flags & OBJ_PIPWNT) && object->paging_in_progress == 0) { 378 vm_object_clear_flag(object, OBJ_PIPWNT); 379 wakeup(object); 380 } 381} 382 383void 384vm_object_pip_wait(vm_object_t object, char *waitid) 385{ 386 387 VM_OBJECT_LOCK_ASSERT(object, MA_OWNED); 388 while (object->paging_in_progress) { 389 object->flags |= OBJ_PIPWNT; 390 VM_OBJECT_SLEEP(object, object, PVM, waitid, 0); 391 } 392} 393 394/* 395 * vm_object_allocate: 396 * 397 * Returns a new object with the given size. 398 */ 399vm_object_t 400vm_object_allocate(objtype_t type, vm_pindex_t size) 401{ 402 vm_object_t object; 403 404 object = (vm_object_t)uma_zalloc(obj_zone, M_WAITOK); 405 _vm_object_allocate(type, size, object); 406 return (object); 407} 408 409 410/* 411 * vm_object_reference: 412 * 413 * Gets another reference to the given object. Note: OBJ_DEAD 414 * objects can be referenced during final cleaning. 415 */ 416void 417vm_object_reference(vm_object_t object) 418{ 419 if (object == NULL) 420 return; 421 VM_OBJECT_LOCK(object); 422 vm_object_reference_locked(object); 423 VM_OBJECT_UNLOCK(object); 424} 425 426/* 427 * vm_object_reference_locked: 428 * 429 * Gets another reference to the given object. 430 * 431 * The object must be locked. 432 */ 433void 434vm_object_reference_locked(vm_object_t object) 435{ 436 struct vnode *vp; 437 438 VM_OBJECT_LOCK_ASSERT(object, MA_OWNED); 439 object->ref_count++; 440 if (object->type == OBJT_VNODE) { 441 vp = object->handle; 442 vref(vp); 443 } 444} 445 446/* 447 * Handle deallocating an object of type OBJT_VNODE. 448 */ 449static void 450vm_object_vndeallocate(vm_object_t object) 451{ 452 struct vnode *vp = (struct vnode *) object->handle; 453 454 VM_OBJECT_LOCK_ASSERT(object, MA_OWNED); 455 KASSERT(object->type == OBJT_VNODE, 456 ("vm_object_vndeallocate: not a vnode object")); 457 KASSERT(vp != NULL, ("vm_object_vndeallocate: missing vp")); 458#ifdef INVARIANTS 459 if (object->ref_count == 0) { 460 vprint("vm_object_vndeallocate", vp); 461 panic("vm_object_vndeallocate: bad object reference count"); 462 } 463#endif 464 465 if (object->ref_count > 1) { 466 object->ref_count--; 467 VM_OBJECT_UNLOCK(object); 468 /* vrele may need the vnode lock. */ 469 vrele(vp); 470 } else { 471 vhold(vp); 472 VM_OBJECT_UNLOCK(object); 473 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY); 474 vdrop(vp); 475 VM_OBJECT_LOCK(object); 476 object->ref_count--; 477 if (object->type == OBJT_DEAD) { 478 VM_OBJECT_UNLOCK(object); 479 VOP_UNLOCK(vp, 0); 480 } else { 481 if (object->ref_count == 0) 482 VOP_UNSET_TEXT(vp); 483 VM_OBJECT_UNLOCK(object); 484 vput(vp); 485 } 486 } 487} 488 489/* 490 * vm_object_deallocate: 491 * 492 * Release a reference to the specified object, 493 * gained either through a vm_object_allocate 494 * or a vm_object_reference call. When all references 495 * are gone, storage associated with this object 496 * may be relinquished. 497 * 498 * No object may be locked. 499 */ 500void 501vm_object_deallocate(vm_object_t object) 502{ 503 vm_object_t temp; 504 505 while (object != NULL) { 506 VM_OBJECT_LOCK(object); 507 if (object->type == OBJT_VNODE) { 508 vm_object_vndeallocate(object); 509 return; 510 } 511 512 KASSERT(object->ref_count != 0, 513 ("vm_object_deallocate: object deallocated too many times: %d", object->type)); 514 515 /* 516 * If the reference count goes to 0 we start calling 517 * vm_object_terminate() on the object chain. 518 * A ref count of 1 may be a special case depending on the 519 * shadow count being 0 or 1. 520 */ 521 object->ref_count--; 522 if (object->ref_count > 1) { 523 VM_OBJECT_UNLOCK(object); 524 return; 525 } else if (object->ref_count == 1) { 526 if (object->shadow_count == 0 && 527 object->handle == NULL && 528 (object->type == OBJT_DEFAULT || 529 object->type == OBJT_SWAP)) { 530 vm_object_set_flag(object, OBJ_ONEMAPPING); 531 } else if ((object->shadow_count == 1) && 532 (object->handle == NULL) && 533 (object->type == OBJT_DEFAULT || 534 object->type == OBJT_SWAP)) { 535 vm_object_t robject; 536 537 robject = LIST_FIRST(&object->shadow_head); 538 KASSERT(robject != NULL, 539 ("vm_object_deallocate: ref_count: %d, shadow_count: %d", 540 object->ref_count, 541 object->shadow_count)); 542 if (!VM_OBJECT_TRYLOCK(robject)) { 543 /* 544 * Avoid a potential deadlock. 545 */ 546 object->ref_count++; 547 VM_OBJECT_UNLOCK(object); 548 /* 549 * More likely than not the thread 550 * holding robject's lock has lower 551 * priority than the current thread. 552 * Let the lower priority thread run. 553 */ 554 pause("vmo_de", 1); 555 continue; 556 } 557 /* 558 * Collapse object into its shadow unless its 559 * shadow is dead. In that case, object will 560 * be deallocated by the thread that is 561 * deallocating its shadow. 562 */ 563 if ((robject->flags & OBJ_DEAD) == 0 && 564 (robject->handle == NULL) && 565 (robject->type == OBJT_DEFAULT || 566 robject->type == OBJT_SWAP)) { 567 568 robject->ref_count++; 569retry: 570 if (robject->paging_in_progress) { 571 VM_OBJECT_UNLOCK(object); 572 vm_object_pip_wait(robject, 573 "objde1"); 574 temp = robject->backing_object; 575 if (object == temp) { 576 VM_OBJECT_LOCK(object); 577 goto retry; 578 } 579 } else if (object->paging_in_progress) { 580 VM_OBJECT_UNLOCK(robject); 581 object->flags |= OBJ_PIPWNT; 582 VM_OBJECT_SLEEP(object, object, 583 PDROP | PVM, "objde2", 0); 584 VM_OBJECT_LOCK(robject); 585 temp = robject->backing_object; 586 if (object == temp) { 587 VM_OBJECT_LOCK(object); 588 goto retry; 589 } 590 } else 591 VM_OBJECT_UNLOCK(object); 592 593 if (robject->ref_count == 1) { 594 robject->ref_count--; 595 object = robject; 596 goto doterm; 597 } 598 object = robject; 599 vm_object_collapse(object); 600 VM_OBJECT_UNLOCK(object); 601 continue; 602 } 603 VM_OBJECT_UNLOCK(robject); 604 } 605 VM_OBJECT_UNLOCK(object); 606 return; 607 } 608doterm: 609 temp = object->backing_object; 610 if (temp != NULL) { 611 VM_OBJECT_LOCK(temp); 612 LIST_REMOVE(object, shadow_list); 613 temp->shadow_count--; 614 VM_OBJECT_UNLOCK(temp); 615 object->backing_object = NULL; 616 } 617 /* 618 * Don't double-terminate, we could be in a termination 619 * recursion due to the terminate having to sync data 620 * to disk. 621 */ 622 if ((object->flags & OBJ_DEAD) == 0) 623 vm_object_terminate(object); 624 else 625 VM_OBJECT_UNLOCK(object); 626 object = temp; 627 } 628} 629 630/* 631 * vm_object_destroy removes the object from the global object list 632 * and frees the space for the object. 633 */ 634void 635vm_object_destroy(vm_object_t object) 636{ 637 638 /* 639 * Remove the object from the global object list. 640 */ 641 mtx_lock(&vm_object_list_mtx); 642 TAILQ_REMOVE(&vm_object_list, object, object_list); 643 mtx_unlock(&vm_object_list_mtx); 644 645 /* 646 * Release the allocation charge. 647 */ 648 if (object->cred != NULL) { 649 KASSERT(object->type == OBJT_DEFAULT || 650 object->type == OBJT_SWAP, 651 ("vm_object_terminate: non-swap obj %p has cred", 652 object)); 653 swap_release_by_cred(object->charge, object->cred); 654 object->charge = 0; 655 crfree(object->cred); 656 object->cred = NULL; 657 } 658 659 /* 660 * Free the space for the object. 661 */ 662 uma_zfree(obj_zone, object); 663} 664 665/* 666 * vm_object_terminate actually destroys the specified object, freeing 667 * up all previously used resources. 668 * 669 * The object must be locked. 670 * This routine may block. 671 */ 672void 673vm_object_terminate(vm_object_t object) 674{ 675 vm_page_t p, p_next; 676 677 VM_OBJECT_LOCK_ASSERT(object, MA_OWNED); 678 679 /* 680 * Make sure no one uses us. 681 */ 682 vm_object_set_flag(object, OBJ_DEAD); 683 684 /* 685 * wait for the pageout daemon to be done with the object 686 */ 687 vm_object_pip_wait(object, "objtrm"); 688 689 KASSERT(!object->paging_in_progress, 690 ("vm_object_terminate: pageout in progress")); 691 692 /* 693 * Clean and free the pages, as appropriate. All references to the 694 * object are gone, so we don't need to lock it. 695 */ 696 if (object->type == OBJT_VNODE) { 697 struct vnode *vp = (struct vnode *)object->handle; 698 699 /* 700 * Clean pages and flush buffers. 701 */ 702 vm_object_page_clean(object, 0, 0, OBJPC_SYNC); 703 VM_OBJECT_UNLOCK(object); 704 705 vinvalbuf(vp, V_SAVE, 0, 0); 706 707 VM_OBJECT_LOCK(object); 708 } 709 710 KASSERT(object->ref_count == 0, 711 ("vm_object_terminate: object with references, ref_count=%d", 712 object->ref_count)); 713 714 /* 715 * Free any remaining pageable pages. This also removes them from the 716 * paging queues. However, don't free wired pages, just remove them 717 * from the object. Rather than incrementally removing each page from 718 * the object, the page and object are reset to any empty state. 719 */ 720 TAILQ_FOREACH_SAFE(p, &object->memq, listq, p_next) { 721 KASSERT(!p->busy && (p->oflags & VPO_BUSY) == 0, 722 ("vm_object_terminate: freeing busy page %p", p)); 723 vm_page_lock(p); 724 /* 725 * Optimize the page's removal from the object by resetting 726 * its "object" field. Specifically, if the page is not 727 * wired, then the effect of this assignment is that 728 * vm_page_free()'s call to vm_page_remove() will return 729 * immediately without modifying the page or the object. 730 */ 731 p->object = NULL; 732 if (p->wire_count == 0) { 733 vm_page_free(p); 734 PCPU_INC(cnt.v_pfree); 735 } 736 vm_page_unlock(p); 737 } 738 /* 739 * If the object contained any pages, then reset it to an empty state. 740 * None of the object's fields, including "resident_page_count", were 741 * modified by the preceding loop. 742 */ 743 if (object->resident_page_count != 0) { 744 object->root = NULL; 745 TAILQ_INIT(&object->memq); 746 object->resident_page_count = 0; 747 if (object->type == OBJT_VNODE) 748 vdrop(object->handle); 749 } 750 751#if VM_NRESERVLEVEL > 0 752 if (__predict_false(!LIST_EMPTY(&object->rvq))) 753 vm_reserv_break_all(object); 754#endif 755 if (__predict_false(object->cache != NULL)) 756 vm_page_cache_free(object, 0, 0); 757 758 /* 759 * Let the pager know object is dead. 760 */ 761 vm_pager_deallocate(object); 762 VM_OBJECT_UNLOCK(object); 763 764 vm_object_destroy(object); 765} 766 767/* 768 * Make the page read-only so that we can clear the object flags. However, if 769 * this is a nosync mmap then the object is likely to stay dirty so do not 770 * mess with the page and do not clear the object flags. Returns TRUE if the 771 * page should be flushed, and FALSE otherwise. 772 */ 773static boolean_t 774vm_object_page_remove_write(vm_page_t p, int flags, boolean_t *clearobjflags) 775{ 776 777 /* 778 * If we have been asked to skip nosync pages and this is a 779 * nosync page, skip it. Note that the object flags were not 780 * cleared in this case so we do not have to set them. 781 */ 782 if ((flags & OBJPC_NOSYNC) != 0 && (p->oflags & VPO_NOSYNC) != 0) { 783 *clearobjflags = FALSE; 784 return (FALSE); 785 } else { 786 pmap_remove_write(p); 787 return (p->dirty != 0); 788 } 789} 790 791/* 792 * vm_object_page_clean 793 * 794 * Clean all dirty pages in the specified range of object. Leaves page 795 * on whatever queue it is currently on. If NOSYNC is set then do not 796 * write out pages with VPO_NOSYNC set (originally comes from MAP_NOSYNC), 797 * leaving the object dirty. 798 * 799 * When stuffing pages asynchronously, allow clustering. XXX we need a 800 * synchronous clustering mode implementation. 801 * 802 * Odd semantics: if start == end, we clean everything. 803 * 804 * The object must be locked. 805 * 806 * Returns FALSE if some page from the range was not written, as 807 * reported by the pager, and TRUE otherwise. 808 */ 809boolean_t 810vm_object_page_clean(vm_object_t object, vm_ooffset_t start, vm_ooffset_t end, 811 int flags) 812{ 813 vm_page_t np, p; 814 vm_pindex_t pi, tend, tstart; 815 int curgeneration, n, pagerflags; 816 boolean_t clearobjflags, eio, res; 817 818 VM_OBJECT_LOCK_ASSERT(object, MA_OWNED); 819 KASSERT(object->type == OBJT_VNODE, ("Not a vnode object")); 820 if ((object->flags & OBJ_MIGHTBEDIRTY) == 0 || 821 object->resident_page_count == 0) 822 return (TRUE); 823 824 pagerflags = (flags & (OBJPC_SYNC | OBJPC_INVAL)) != 0 ? 825 VM_PAGER_PUT_SYNC : VM_PAGER_CLUSTER_OK; 826 pagerflags |= (flags & OBJPC_INVAL) != 0 ? VM_PAGER_PUT_INVAL : 0; 827 828 tstart = OFF_TO_IDX(start); 829 tend = (end == 0) ? object->size : OFF_TO_IDX(end + PAGE_MASK); 830 clearobjflags = tstart == 0 && tend >= object->size; 831 res = TRUE; 832 833rescan: 834 curgeneration = object->generation; 835 836 for (p = vm_page_find_least(object, tstart); p != NULL; p = np) { 837 pi = p->pindex; 838 if (pi >= tend) 839 break; 840 np = TAILQ_NEXT(p, listq); 841 if (p->valid == 0) 842 continue; 843 if (vm_page_sleep_if_busy(p, TRUE, "vpcwai")) { 844 if (object->generation != curgeneration) { 845 if ((flags & OBJPC_SYNC) != 0) 846 goto rescan; 847 else 848 clearobjflags = FALSE; 849 } 850 np = vm_page_find_least(object, pi); 851 continue; 852 } 853 if (!vm_object_page_remove_write(p, flags, &clearobjflags)) 854 continue; 855 856 n = vm_object_page_collect_flush(object, p, pagerflags, 857 flags, &clearobjflags, &eio); 858 if (eio) { 859 res = FALSE; 860 clearobjflags = FALSE; 861 } 862 if (object->generation != curgeneration) { 863 if ((flags & OBJPC_SYNC) != 0) 864 goto rescan; 865 else 866 clearobjflags = FALSE; 867 } 868 869 /* 870 * If the VOP_PUTPAGES() did a truncated write, so 871 * that even the first page of the run is not fully 872 * written, vm_pageout_flush() returns 0 as the run 873 * length. Since the condition that caused truncated 874 * write may be permanent, e.g. exhausted free space, 875 * accepting n == 0 would cause an infinite loop. 876 * 877 * Forwarding the iterator leaves the unwritten page 878 * behind, but there is not much we can do there if 879 * filesystem refuses to write it. 880 */ 881 if (n == 0) { 882 n = 1; 883 clearobjflags = FALSE; 884 } 885 np = vm_page_find_least(object, pi + n); 886 } 887#if 0 888 VOP_FSYNC(vp, (pagerflags & VM_PAGER_PUT_SYNC) ? MNT_WAIT : 0); 889#endif 890 891 if (clearobjflags) 892 vm_object_clear_flag(object, OBJ_MIGHTBEDIRTY); 893 return (res); 894} 895 896static int 897vm_object_page_collect_flush(vm_object_t object, vm_page_t p, int pagerflags, 898 int flags, boolean_t *clearobjflags, boolean_t *eio) 899{ 900 vm_page_t ma[vm_pageout_page_count], p_first, tp; 901 int count, i, mreq, runlen; 902 903 vm_page_lock_assert(p, MA_NOTOWNED); 904 VM_OBJECT_LOCK_ASSERT(object, MA_OWNED); 905 906 count = 1; 907 mreq = 0; 908 909 for (tp = p; count < vm_pageout_page_count; count++) { 910 tp = vm_page_next(tp); 911 if (tp == NULL || tp->busy != 0 || (tp->oflags & VPO_BUSY) != 0) 912 break; 913 if (!vm_object_page_remove_write(tp, flags, clearobjflags)) 914 break; 915 } 916 917 for (p_first = p; count < vm_pageout_page_count; count++) { 918 tp = vm_page_prev(p_first); 919 if (tp == NULL || tp->busy != 0 || (tp->oflags & VPO_BUSY) != 0) 920 break; 921 if (!vm_object_page_remove_write(tp, flags, clearobjflags)) 922 break; 923 p_first = tp; 924 mreq++; 925 } 926 927 for (tp = p_first, i = 0; i < count; tp = TAILQ_NEXT(tp, listq), i++) 928 ma[i] = tp; 929 930 vm_pageout_flush(ma, count, pagerflags, mreq, &runlen, eio); 931 return (runlen); 932} 933 934/* 935 * Note that there is absolutely no sense in writing out 936 * anonymous objects, so we track down the vnode object 937 * to write out. 938 * We invalidate (remove) all pages from the address space 939 * for semantic correctness. 940 * 941 * If the backing object is a device object with unmanaged pages, then any 942 * mappings to the specified range of pages must be removed before this 943 * function is called. 944 * 945 * Note: certain anonymous maps, such as MAP_NOSYNC maps, 946 * may start out with a NULL object. 947 */ 948boolean_t 949vm_object_sync(vm_object_t object, vm_ooffset_t offset, vm_size_t size, 950 boolean_t syncio, boolean_t invalidate) 951{ 952 vm_object_t backing_object; 953 struct vnode *vp; 954 struct mount *mp; 955 int error, flags, fsync_after; 956 boolean_t res; 957 958 if (object == NULL) 959 return (TRUE); 960 res = TRUE; 961 error = 0; 962 VM_OBJECT_LOCK(object); 963 while ((backing_object = object->backing_object) != NULL) { 964 VM_OBJECT_LOCK(backing_object); 965 offset += object->backing_object_offset; 966 VM_OBJECT_UNLOCK(object); 967 object = backing_object; 968 if (object->size < OFF_TO_IDX(offset + size)) 969 size = IDX_TO_OFF(object->size) - offset; 970 } 971 /* 972 * Flush pages if writing is allowed, invalidate them 973 * if invalidation requested. Pages undergoing I/O 974 * will be ignored by vm_object_page_remove(). 975 * 976 * We cannot lock the vnode and then wait for paging 977 * to complete without deadlocking against vm_fault. 978 * Instead we simply call vm_object_page_remove() and 979 * allow it to block internally on a page-by-page 980 * basis when it encounters pages undergoing async 981 * I/O. 982 */ 983 if (object->type == OBJT_VNODE && 984 (object->flags & OBJ_MIGHTBEDIRTY) != 0) { 985 vp = object->handle; 986 VM_OBJECT_UNLOCK(object); 987 (void) vn_start_write(vp, &mp, V_WAIT); 988 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY); 989 if (syncio && !invalidate && offset == 0 && 990 OFF_TO_IDX(size) == object->size) { 991 /* 992 * If syncing the whole mapping of the file, 993 * it is faster to schedule all the writes in 994 * async mode, also allowing the clustering, 995 * and then wait for i/o to complete. 996 */ 997 flags = 0; 998 fsync_after = TRUE; 999 } else { 1000 flags = (syncio || invalidate) ? OBJPC_SYNC : 0; 1001 flags |= invalidate ? (OBJPC_SYNC | OBJPC_INVAL) : 0; 1002 fsync_after = FALSE; 1003 } 1004 VM_OBJECT_LOCK(object); 1005 res = vm_object_page_clean(object, offset, offset + size, 1006 flags); 1007 VM_OBJECT_UNLOCK(object); 1008 if (fsync_after) 1009 error = VOP_FSYNC(vp, MNT_WAIT, curthread); 1010 VOP_UNLOCK(vp, 0); 1011 vn_finished_write(mp); 1012 if (error != 0) 1013 res = FALSE; 1014 VM_OBJECT_LOCK(object); 1015 } 1016 if ((object->type == OBJT_VNODE || 1017 object->type == OBJT_DEVICE) && invalidate) { 1018 if (object->type == OBJT_DEVICE) 1019 /* 1020 * The option OBJPR_NOTMAPPED must be passed here 1021 * because vm_object_page_remove() cannot remove 1022 * unmanaged mappings. 1023 */ 1024 flags = OBJPR_NOTMAPPED; 1025 else if (old_msync) 1026 flags = 0; 1027 else 1028 flags = OBJPR_CLEANONLY; 1029 vm_object_page_remove(object, OFF_TO_IDX(offset), 1030 OFF_TO_IDX(offset + size + PAGE_MASK), flags); 1031 } 1032 VM_OBJECT_UNLOCK(object); 1033 return (res); 1034} 1035 1036/* 1037 * vm_object_madvise: 1038 * 1039 * Implements the madvise function at the object/page level. 1040 * 1041 * MADV_WILLNEED (any object) 1042 * 1043 * Activate the specified pages if they are resident. 1044 * 1045 * MADV_DONTNEED (any object) 1046 * 1047 * Deactivate the specified pages if they are resident. 1048 * 1049 * MADV_FREE (OBJT_DEFAULT/OBJT_SWAP objects, 1050 * OBJ_ONEMAPPING only) 1051 * 1052 * Deactivate and clean the specified pages if they are 1053 * resident. This permits the process to reuse the pages 1054 * without faulting or the kernel to reclaim the pages 1055 * without I/O. 1056 */ 1057void 1058vm_object_madvise(vm_object_t object, vm_pindex_t pindex, vm_pindex_t end, 1059 int advise) 1060{ 1061 vm_pindex_t tpindex; 1062 vm_object_t backing_object, tobject; 1063 vm_page_t m; 1064 1065 if (object == NULL) 1066 return; 1067 VM_OBJECT_LOCK(object); 1068 /* 1069 * Locate and adjust resident pages 1070 */ 1071 for (; pindex < end; pindex += 1) { 1072relookup: 1073 tobject = object; 1074 tpindex = pindex; 1075shadowlookup: 1076 /* 1077 * MADV_FREE only operates on OBJT_DEFAULT or OBJT_SWAP pages 1078 * and those pages must be OBJ_ONEMAPPING. 1079 */ 1080 if (advise == MADV_FREE) { 1081 if ((tobject->type != OBJT_DEFAULT && 1082 tobject->type != OBJT_SWAP) || 1083 (tobject->flags & OBJ_ONEMAPPING) == 0) { 1084 goto unlock_tobject; 1085 } 1086 } else if ((tobject->flags & OBJ_UNMANAGED) != 0) 1087 goto unlock_tobject; 1088 m = vm_page_lookup(tobject, tpindex); 1089 if (m == NULL && advise == MADV_WILLNEED) { 1090 /* 1091 * If the page is cached, reactivate it. 1092 */ 1093 m = vm_page_alloc(tobject, tpindex, VM_ALLOC_IFCACHED | 1094 VM_ALLOC_NOBUSY); 1095 } 1096 if (m == NULL) { 1097 /* 1098 * There may be swap even if there is no backing page 1099 */ 1100 if (advise == MADV_FREE && tobject->type == OBJT_SWAP) 1101 swap_pager_freespace(tobject, tpindex, 1); 1102 /* 1103 * next object 1104 */ 1105 backing_object = tobject->backing_object; 1106 if (backing_object == NULL) 1107 goto unlock_tobject; 1108 VM_OBJECT_LOCK(backing_object); 1109 tpindex += OFF_TO_IDX(tobject->backing_object_offset); 1110 if (tobject != object) 1111 VM_OBJECT_UNLOCK(tobject); 1112 tobject = backing_object; 1113 goto shadowlookup; 1114 } else if (m->valid != VM_PAGE_BITS_ALL) 1115 goto unlock_tobject; 1116 /* 1117 * If the page is not in a normal state, skip it. 1118 */ 1119 vm_page_lock(m); 1120 if (m->hold_count != 0 || m->wire_count != 0) { 1121 vm_page_unlock(m); 1122 goto unlock_tobject; 1123 } 1124 KASSERT((m->flags & PG_FICTITIOUS) == 0, 1125 ("vm_object_madvise: page %p is fictitious", m)); 1126 KASSERT((m->oflags & VPO_UNMANAGED) == 0, 1127 ("vm_object_madvise: page %p is not managed", m)); 1128 if ((m->oflags & VPO_BUSY) || m->busy) { 1129 if (advise == MADV_WILLNEED) { 1130 /* 1131 * Reference the page before unlocking and 1132 * sleeping so that the page daemon is less 1133 * likely to reclaim it. 1134 */ 1135 vm_page_aflag_set(m, PGA_REFERENCED); 1136 } 1137 vm_page_unlock(m); 1138 if (object != tobject) 1139 VM_OBJECT_UNLOCK(object); 1140 m->oflags |= VPO_WANTED; 1141 VM_OBJECT_SLEEP(tobject, m, PDROP | PVM, "madvpo", 0); 1142 VM_OBJECT_LOCK(object); 1143 goto relookup; 1144 } 1145 if (advise == MADV_WILLNEED) { 1146 vm_page_activate(m); 1147 } else if (advise == MADV_DONTNEED) { 1148 vm_page_dontneed(m); 1149 } else if (advise == MADV_FREE) { 1150 /* 1151 * Mark the page clean. This will allow the page 1152 * to be freed up by the system. However, such pages 1153 * are often reused quickly by malloc()/free() 1154 * so we do not do anything that would cause 1155 * a page fault if we can help it. 1156 * 1157 * Specifically, we do not try to actually free 1158 * the page now nor do we try to put it in the 1159 * cache (which would cause a page fault on reuse). 1160 * 1161 * But we do make the page is freeable as we 1162 * can without actually taking the step of unmapping 1163 * it. 1164 */ 1165 pmap_clear_modify(m); 1166 m->dirty = 0; 1167 m->act_count = 0; 1168 vm_page_dontneed(m); 1169 } 1170 vm_page_unlock(m); 1171 if (advise == MADV_FREE && tobject->type == OBJT_SWAP) 1172 swap_pager_freespace(tobject, tpindex, 1); 1173unlock_tobject: 1174 if (tobject != object) 1175 VM_OBJECT_UNLOCK(tobject); 1176 } 1177 VM_OBJECT_UNLOCK(object); 1178} 1179 1180/* 1181 * vm_object_shadow: 1182 * 1183 * Create a new object which is backed by the 1184 * specified existing object range. The source 1185 * object reference is deallocated. 1186 * 1187 * The new object and offset into that object 1188 * are returned in the source parameters. 1189 */ 1190void 1191vm_object_shadow( 1192 vm_object_t *object, /* IN/OUT */ 1193 vm_ooffset_t *offset, /* IN/OUT */ 1194 vm_size_t length) 1195{ 1196 vm_object_t source; 1197 vm_object_t result; 1198 1199 source = *object; 1200 1201 /* 1202 * Don't create the new object if the old object isn't shared. 1203 */ 1204 if (source != NULL) { 1205 VM_OBJECT_LOCK(source); 1206 if (source->ref_count == 1 && 1207 source->handle == NULL && 1208 (source->type == OBJT_DEFAULT || 1209 source->type == OBJT_SWAP)) { 1210 VM_OBJECT_UNLOCK(source); 1211 return; 1212 } 1213 VM_OBJECT_UNLOCK(source); 1214 } 1215 1216 /* 1217 * Allocate a new object with the given length. 1218 */ 1219 result = vm_object_allocate(OBJT_DEFAULT, atop(length)); 1220 1221 /* 1222 * The new object shadows the source object, adding a reference to it. 1223 * Our caller changes his reference to point to the new object, 1224 * removing a reference to the source object. Net result: no change 1225 * of reference count. 1226 * 1227 * Try to optimize the result object's page color when shadowing 1228 * in order to maintain page coloring consistency in the combined 1229 * shadowed object. 1230 */ 1231 result->backing_object = source; 1232 /* 1233 * Store the offset into the source object, and fix up the offset into 1234 * the new object. 1235 */ 1236 result->backing_object_offset = *offset; 1237 if (source != NULL) { 1238 VM_OBJECT_LOCK(source); 1239 LIST_INSERT_HEAD(&source->shadow_head, result, shadow_list); 1240 source->shadow_count++; 1241#if VM_NRESERVLEVEL > 0 1242 result->flags |= source->flags & OBJ_COLORED; 1243 result->pg_color = (source->pg_color + OFF_TO_IDX(*offset)) & 1244 ((1 << (VM_NFREEORDER - 1)) - 1); 1245#endif 1246 VM_OBJECT_UNLOCK(source); 1247 } 1248 1249 1250 /* 1251 * Return the new things 1252 */ 1253 *offset = 0; 1254 *object = result; 1255} 1256 1257/* 1258 * vm_object_split: 1259 * 1260 * Split the pages in a map entry into a new object. This affords 1261 * easier removal of unused pages, and keeps object inheritance from 1262 * being a negative impact on memory usage. 1263 */ 1264void 1265vm_object_split(vm_map_entry_t entry) 1266{ 1267 vm_page_t m, m_next; 1268 vm_object_t orig_object, new_object, source; 1269 vm_pindex_t idx, offidxstart; 1270 vm_size_t size; 1271 1272 orig_object = entry->object.vm_object; 1273 if (orig_object->type != OBJT_DEFAULT && orig_object->type != OBJT_SWAP) 1274 return; 1275 if (orig_object->ref_count <= 1) 1276 return; 1277 VM_OBJECT_UNLOCK(orig_object); 1278 1279 offidxstart = OFF_TO_IDX(entry->offset); 1280 size = atop(entry->end - entry->start); 1281 1282 /* 1283 * If swap_pager_copy() is later called, it will convert new_object 1284 * into a swap object. 1285 */ 1286 new_object = vm_object_allocate(OBJT_DEFAULT, size); 1287 1288 /* 1289 * At this point, the new object is still private, so the order in 1290 * which the original and new objects are locked does not matter. 1291 */ 1292 VM_OBJECT_LOCK(new_object); 1293 VM_OBJECT_LOCK(orig_object); 1294 source = orig_object->backing_object; 1295 if (source != NULL) { 1296 VM_OBJECT_LOCK(source); 1297 if ((source->flags & OBJ_DEAD) != 0) { 1298 VM_OBJECT_UNLOCK(source); 1299 VM_OBJECT_UNLOCK(orig_object); 1300 VM_OBJECT_UNLOCK(new_object); 1301 vm_object_deallocate(new_object); 1302 VM_OBJECT_LOCK(orig_object); 1303 return; 1304 } 1305 LIST_INSERT_HEAD(&source->shadow_head, 1306 new_object, shadow_list); 1307 source->shadow_count++; 1308 vm_object_reference_locked(source); /* for new_object */ 1309 vm_object_clear_flag(source, OBJ_ONEMAPPING); 1310 VM_OBJECT_UNLOCK(source); 1311 new_object->backing_object_offset = 1312 orig_object->backing_object_offset + entry->offset; 1313 new_object->backing_object = source; 1314 } 1315 if (orig_object->cred != NULL) { 1316 new_object->cred = orig_object->cred; 1317 crhold(orig_object->cred); 1318 new_object->charge = ptoa(size); 1319 KASSERT(orig_object->charge >= ptoa(size), 1320 ("orig_object->charge < 0")); 1321 orig_object->charge -= ptoa(size); 1322 } 1323retry: 1324 m = vm_page_find_least(orig_object, offidxstart); 1325 for (; m != NULL && (idx = m->pindex - offidxstart) < size; 1326 m = m_next) { 1327 m_next = TAILQ_NEXT(m, listq); 1328 1329 /* 1330 * We must wait for pending I/O to complete before we can 1331 * rename the page. 1332 * 1333 * We do not have to VM_PROT_NONE the page as mappings should 1334 * not be changed by this operation. 1335 */ 1336 if ((m->oflags & VPO_BUSY) || m->busy) { 1337 VM_OBJECT_UNLOCK(new_object); 1338 m->oflags |= VPO_WANTED; 1339 VM_OBJECT_SLEEP(orig_object, m, PVM, "spltwt", 0); 1340 VM_OBJECT_LOCK(new_object); 1341 goto retry; 1342 } 1343#if VM_NRESERVLEVEL > 0 1344 /* 1345 * If some of the reservation's allocated pages remain with 1346 * the original object, then transferring the reservation to 1347 * the new object is neither particularly beneficial nor 1348 * particularly harmful as compared to leaving the reservation 1349 * with the original object. If, however, all of the 1350 * reservation's allocated pages are transferred to the new 1351 * object, then transferring the reservation is typically 1352 * beneficial. Determining which of these two cases applies 1353 * would be more costly than unconditionally renaming the 1354 * reservation. 1355 */ 1356 vm_reserv_rename(m, new_object, orig_object, offidxstart); 1357#endif 1358 vm_page_lock(m); 1359 vm_page_rename(m, new_object, idx); 1360 vm_page_unlock(m); 1361 /* page automatically made dirty by rename and cache handled */ 1362 vm_page_busy(m); 1363 } 1364 if (orig_object->type == OBJT_SWAP) { 1365 /* 1366 * swap_pager_copy() can sleep, in which case the orig_object's 1367 * and new_object's locks are released and reacquired. 1368 */ 1369 swap_pager_copy(orig_object, new_object, offidxstart, 0); 1370 1371 /* 1372 * Transfer any cached pages from orig_object to new_object. 1373 * If swap_pager_copy() found swapped out pages within the 1374 * specified range of orig_object, then it changed 1375 * new_object's type to OBJT_SWAP when it transferred those 1376 * pages to new_object. Otherwise, new_object's type 1377 * should still be OBJT_DEFAULT and orig_object should not 1378 * contain any cached pages within the specified range. 1379 */ 1380 if (__predict_false(orig_object->cache != NULL)) 1381 vm_page_cache_transfer(orig_object, offidxstart, 1382 new_object); 1383 } 1384 VM_OBJECT_UNLOCK(orig_object); 1385 TAILQ_FOREACH(m, &new_object->memq, listq) 1386 vm_page_wakeup(m); 1387 VM_OBJECT_UNLOCK(new_object); 1388 entry->object.vm_object = new_object; 1389 entry->offset = 0LL; 1390 vm_object_deallocate(orig_object); 1391 VM_OBJECT_LOCK(new_object); 1392} 1393 1394#define OBSC_TEST_ALL_SHADOWED 0x0001 1395#define OBSC_COLLAPSE_NOWAIT 0x0002 1396#define OBSC_COLLAPSE_WAIT 0x0004 1397 1398static int 1399vm_object_backing_scan(vm_object_t object, int op) 1400{ 1401 int r = 1; 1402 vm_page_t p; 1403 vm_object_t backing_object; 1404 vm_pindex_t backing_offset_index; 1405 1406 VM_OBJECT_LOCK_ASSERT(object, MA_OWNED); 1407 VM_OBJECT_LOCK_ASSERT(object->backing_object, MA_OWNED); 1408 1409 backing_object = object->backing_object; 1410 backing_offset_index = OFF_TO_IDX(object->backing_object_offset); 1411 1412 /* 1413 * Initial conditions 1414 */ 1415 if (op & OBSC_TEST_ALL_SHADOWED) { 1416 /* 1417 * We do not want to have to test for the existence of cache 1418 * or swap pages in the backing object. XXX but with the 1419 * new swapper this would be pretty easy to do. 1420 * 1421 * XXX what about anonymous MAP_SHARED memory that hasn't 1422 * been ZFOD faulted yet? If we do not test for this, the 1423 * shadow test may succeed! XXX 1424 */ 1425 if (backing_object->type != OBJT_DEFAULT) { 1426 return (0); 1427 } 1428 } 1429 if (op & OBSC_COLLAPSE_WAIT) { 1430 vm_object_set_flag(backing_object, OBJ_DEAD); 1431 } 1432 1433 /* 1434 * Our scan 1435 */ 1436 p = TAILQ_FIRST(&backing_object->memq); 1437 while (p) { 1438 vm_page_t next = TAILQ_NEXT(p, listq); 1439 vm_pindex_t new_pindex = p->pindex - backing_offset_index; 1440 1441 if (op & OBSC_TEST_ALL_SHADOWED) { 1442 vm_page_t pp; 1443 1444 /* 1445 * Ignore pages outside the parent object's range 1446 * and outside the parent object's mapping of the 1447 * backing object. 1448 * 1449 * note that we do not busy the backing object's 1450 * page. 1451 */ 1452 if ( 1453 p->pindex < backing_offset_index || 1454 new_pindex >= object->size 1455 ) { 1456 p = next; 1457 continue; 1458 } 1459 1460 /* 1461 * See if the parent has the page or if the parent's 1462 * object pager has the page. If the parent has the 1463 * page but the page is not valid, the parent's 1464 * object pager must have the page. 1465 * 1466 * If this fails, the parent does not completely shadow 1467 * the object and we might as well give up now. 1468 */ 1469 1470 pp = vm_page_lookup(object, new_pindex); 1471 if ( 1472 (pp == NULL || pp->valid == 0) && 1473 !vm_pager_has_page(object, new_pindex, NULL, NULL) 1474 ) { 1475 r = 0; 1476 break; 1477 } 1478 } 1479 1480 /* 1481 * Check for busy page 1482 */ 1483 if (op & (OBSC_COLLAPSE_WAIT | OBSC_COLLAPSE_NOWAIT)) { 1484 vm_page_t pp; 1485 1486 if (op & OBSC_COLLAPSE_NOWAIT) { 1487 if ((p->oflags & VPO_BUSY) || 1488 !p->valid || 1489 p->busy) { 1490 p = next; 1491 continue; 1492 } 1493 } else if (op & OBSC_COLLAPSE_WAIT) { 1494 if ((p->oflags & VPO_BUSY) || p->busy) { 1495 VM_OBJECT_UNLOCK(object); 1496 p->oflags |= VPO_WANTED; 1497 VM_OBJECT_SLEEP(backing_object, p, 1498 PDROP | PVM, "vmocol", 0); 1499 VM_OBJECT_LOCK(object); 1500 VM_OBJECT_LOCK(backing_object); 1501 /* 1502 * If we slept, anything could have 1503 * happened. Since the object is 1504 * marked dead, the backing offset 1505 * should not have changed so we 1506 * just restart our scan. 1507 */ 1508 p = TAILQ_FIRST(&backing_object->memq); 1509 continue; 1510 } 1511 } 1512 1513 KASSERT( 1514 p->object == backing_object, 1515 ("vm_object_backing_scan: object mismatch") 1516 ); 1517 1518 /* 1519 * Destroy any associated swap 1520 */ 1521 if (backing_object->type == OBJT_SWAP) { 1522 swap_pager_freespace( 1523 backing_object, 1524 p->pindex, 1525 1 1526 ); 1527 } 1528 1529 if ( 1530 p->pindex < backing_offset_index || 1531 new_pindex >= object->size 1532 ) { 1533 /* 1534 * Page is out of the parent object's range, we 1535 * can simply destroy it. 1536 */ 1537 vm_page_lock(p); 1538 KASSERT(!pmap_page_is_mapped(p), 1539 ("freeing mapped page %p", p)); 1540 if (p->wire_count == 0) 1541 vm_page_free(p); 1542 else 1543 vm_page_remove(p); 1544 vm_page_unlock(p); 1545 p = next; 1546 continue; 1547 } 1548 1549 pp = vm_page_lookup(object, new_pindex); 1550 if ( 1551 (op & OBSC_COLLAPSE_NOWAIT) != 0 && 1552 (pp != NULL && pp->valid == 0) 1553 ) { 1554 /* 1555 * The page in the parent is not (yet) valid. 1556 * We don't know anything about the state of 1557 * the original page. It might be mapped, 1558 * so we must avoid the next if here. 1559 * 1560 * This is due to a race in vm_fault() where 1561 * we must unbusy the original (backing_obj) 1562 * page before we can (re)lock the parent. 1563 * Hence we can get here. 1564 */ 1565 p = next; 1566 continue; 1567 } 1568 if ( 1569 pp != NULL || 1570 vm_pager_has_page(object, new_pindex, NULL, NULL) 1571 ) { 1572 /* 1573 * page already exists in parent OR swap exists 1574 * for this location in the parent. Destroy 1575 * the original page from the backing object. 1576 * 1577 * Leave the parent's page alone 1578 */ 1579 vm_page_lock(p); 1580 KASSERT(!pmap_page_is_mapped(p), 1581 ("freeing mapped page %p", p)); 1582 if (p->wire_count == 0) 1583 vm_page_free(p); 1584 else 1585 vm_page_remove(p); 1586 vm_page_unlock(p); 1587 p = next; 1588 continue; 1589 } 1590 1591#if VM_NRESERVLEVEL > 0 1592 /* 1593 * Rename the reservation. 1594 */ 1595 vm_reserv_rename(p, object, backing_object, 1596 backing_offset_index); 1597#endif 1598 1599 /* 1600 * Page does not exist in parent, rename the 1601 * page from the backing object to the main object. 1602 * 1603 * If the page was mapped to a process, it can remain 1604 * mapped through the rename. 1605 */ 1606 vm_page_lock(p); 1607 vm_page_rename(p, object, new_pindex); 1608 vm_page_unlock(p); 1609 /* page automatically made dirty by rename */ 1610 } 1611 p = next; 1612 } 1613 return (r); 1614} 1615 1616 1617/* 1618 * this version of collapse allows the operation to occur earlier and 1619 * when paging_in_progress is true for an object... This is not a complete 1620 * operation, but should plug 99.9% of the rest of the leaks. 1621 */ 1622static void 1623vm_object_qcollapse(vm_object_t object) 1624{ 1625 vm_object_t backing_object = object->backing_object; 1626 1627 VM_OBJECT_LOCK_ASSERT(object, MA_OWNED); 1628 VM_OBJECT_LOCK_ASSERT(backing_object, MA_OWNED); 1629 1630 if (backing_object->ref_count != 1) 1631 return; 1632 1633 vm_object_backing_scan(object, OBSC_COLLAPSE_NOWAIT); 1634} 1635 1636/* 1637 * vm_object_collapse: 1638 * 1639 * Collapse an object with the object backing it. 1640 * Pages in the backing object are moved into the 1641 * parent, and the backing object is deallocated. 1642 */ 1643void 1644vm_object_collapse(vm_object_t object) 1645{ 1646 VM_OBJECT_LOCK_ASSERT(object, MA_OWNED); 1647 1648 while (TRUE) { 1649 vm_object_t backing_object; 1650 1651 /* 1652 * Verify that the conditions are right for collapse: 1653 * 1654 * The object exists and the backing object exists. 1655 */ 1656 if ((backing_object = object->backing_object) == NULL) 1657 break; 1658 1659 /* 1660 * we check the backing object first, because it is most likely 1661 * not collapsable. 1662 */ 1663 VM_OBJECT_LOCK(backing_object); 1664 if (backing_object->handle != NULL || 1665 (backing_object->type != OBJT_DEFAULT && 1666 backing_object->type != OBJT_SWAP) || 1667 (backing_object->flags & OBJ_DEAD) || 1668 object->handle != NULL || 1669 (object->type != OBJT_DEFAULT && 1670 object->type != OBJT_SWAP) || 1671 (object->flags & OBJ_DEAD)) { 1672 VM_OBJECT_UNLOCK(backing_object); 1673 break; 1674 } 1675 1676 if ( 1677 object->paging_in_progress != 0 || 1678 backing_object->paging_in_progress != 0 1679 ) { 1680 vm_object_qcollapse(object); 1681 VM_OBJECT_UNLOCK(backing_object); 1682 break; 1683 } 1684 /* 1685 * We know that we can either collapse the backing object (if 1686 * the parent is the only reference to it) or (perhaps) have 1687 * the parent bypass the object if the parent happens to shadow 1688 * all the resident pages in the entire backing object. 1689 * 1690 * This is ignoring pager-backed pages such as swap pages. 1691 * vm_object_backing_scan fails the shadowing test in this 1692 * case. 1693 */ 1694 if (backing_object->ref_count == 1) { 1695 /* 1696 * If there is exactly one reference to the backing 1697 * object, we can collapse it into the parent. 1698 */ 1699 vm_object_backing_scan(object, OBSC_COLLAPSE_WAIT); 1700 1701#if VM_NRESERVLEVEL > 0 1702 /* 1703 * Break any reservations from backing_object. 1704 */ 1705 if (__predict_false(!LIST_EMPTY(&backing_object->rvq))) 1706 vm_reserv_break_all(backing_object); 1707#endif 1708 1709 /* 1710 * Move the pager from backing_object to object. 1711 */ 1712 if (backing_object->type == OBJT_SWAP) { 1713 /* 1714 * swap_pager_copy() can sleep, in which case 1715 * the backing_object's and object's locks are 1716 * released and reacquired. 1717 * Since swap_pager_copy() is being asked to 1718 * destroy the source, it will change the 1719 * backing_object's type to OBJT_DEFAULT. 1720 */ 1721 swap_pager_copy( 1722 backing_object, 1723 object, 1724 OFF_TO_IDX(object->backing_object_offset), TRUE); 1725 1726 /* 1727 * Free any cached pages from backing_object. 1728 */ 1729 if (__predict_false(backing_object->cache != NULL)) 1730 vm_page_cache_free(backing_object, 0, 0); 1731 } 1732 /* 1733 * Object now shadows whatever backing_object did. 1734 * Note that the reference to 1735 * backing_object->backing_object moves from within 1736 * backing_object to within object. 1737 */ 1738 LIST_REMOVE(object, shadow_list); 1739 backing_object->shadow_count--; 1740 if (backing_object->backing_object) { 1741 VM_OBJECT_LOCK(backing_object->backing_object); 1742 LIST_REMOVE(backing_object, shadow_list); 1743 LIST_INSERT_HEAD( 1744 &backing_object->backing_object->shadow_head, 1745 object, shadow_list); 1746 /* 1747 * The shadow_count has not changed. 1748 */ 1749 VM_OBJECT_UNLOCK(backing_object->backing_object); 1750 } 1751 object->backing_object = backing_object->backing_object; 1752 object->backing_object_offset += 1753 backing_object->backing_object_offset; 1754 1755 /* 1756 * Discard backing_object. 1757 * 1758 * Since the backing object has no pages, no pager left, 1759 * and no object references within it, all that is 1760 * necessary is to dispose of it. 1761 */ 1762 KASSERT(backing_object->ref_count == 1, ( 1763"backing_object %p was somehow re-referenced during collapse!", 1764 backing_object)); 1765 VM_OBJECT_UNLOCK(backing_object); 1766 vm_object_destroy(backing_object); 1767 1768 object_collapses++; 1769 } else { 1770 vm_object_t new_backing_object; 1771 1772 /* 1773 * If we do not entirely shadow the backing object, 1774 * there is nothing we can do so we give up. 1775 */ 1776 if (object->resident_page_count != object->size && 1777 vm_object_backing_scan(object, 1778 OBSC_TEST_ALL_SHADOWED) == 0) { 1779 VM_OBJECT_UNLOCK(backing_object); 1780 break; 1781 } 1782 1783 /* 1784 * Make the parent shadow the next object in the 1785 * chain. Deallocating backing_object will not remove 1786 * it, since its reference count is at least 2. 1787 */ 1788 LIST_REMOVE(object, shadow_list); 1789 backing_object->shadow_count--; 1790 1791 new_backing_object = backing_object->backing_object; 1792 if ((object->backing_object = new_backing_object) != NULL) { 1793 VM_OBJECT_LOCK(new_backing_object); 1794 LIST_INSERT_HEAD( 1795 &new_backing_object->shadow_head, 1796 object, 1797 shadow_list 1798 ); 1799 new_backing_object->shadow_count++; 1800 vm_object_reference_locked(new_backing_object); 1801 VM_OBJECT_UNLOCK(new_backing_object); 1802 object->backing_object_offset += 1803 backing_object->backing_object_offset; 1804 } 1805 1806 /* 1807 * Drop the reference count on backing_object. Since 1808 * its ref_count was at least 2, it will not vanish. 1809 */ 1810 backing_object->ref_count--; 1811 VM_OBJECT_UNLOCK(backing_object); 1812 object_bypasses++; 1813 } 1814 1815 /* 1816 * Try again with this object's new backing object. 1817 */ 1818 } 1819} 1820 1821/* 1822 * vm_object_page_remove: 1823 * 1824 * For the given object, either frees or invalidates each of the 1825 * specified pages. In general, a page is freed. However, if a page is 1826 * wired for any reason other than the existence of a managed, wired 1827 * mapping, then it may be invalidated but not removed from the object. 1828 * Pages are specified by the given range ["start", "end") and the option 1829 * OBJPR_CLEANONLY. As a special case, if "end" is zero, then the range 1830 * extends from "start" to the end of the object. If the option 1831 * OBJPR_CLEANONLY is specified, then only the non-dirty pages within the 1832 * specified range are affected. If the option OBJPR_NOTMAPPED is 1833 * specified, then the pages within the specified range must have no 1834 * mappings. Otherwise, if this option is not specified, any mappings to 1835 * the specified pages are removed before the pages are freed or 1836 * invalidated. 1837 * 1838 * In general, this operation should only be performed on objects that 1839 * contain managed pages. There are, however, two exceptions. First, it 1840 * is performed on the kernel and kmem objects by vm_map_entry_delete(). 1841 * Second, it is used by msync(..., MS_INVALIDATE) to invalidate device- 1842 * backed pages. In both of these cases, the option OBJPR_CLEANONLY must 1843 * not be specified and the option OBJPR_NOTMAPPED must be specified. 1844 * 1845 * The object must be locked. 1846 */ 1847void 1848vm_object_page_remove(vm_object_t object, vm_pindex_t start, vm_pindex_t end, 1849 int options) 1850{ 1851 vm_page_t p, next; 1852 int wirings; 1853 1854 VM_OBJECT_LOCK_ASSERT(object, MA_OWNED); 1855 KASSERT((object->flags & OBJ_UNMANAGED) == 0 || 1856 (options & (OBJPR_CLEANONLY | OBJPR_NOTMAPPED)) == OBJPR_NOTMAPPED, 1857 ("vm_object_page_remove: illegal options for object %p", object)); 1858 if (object->resident_page_count == 0) 1859 goto skipmemq; 1860 vm_object_pip_add(object, 1); 1861again: 1862 p = vm_page_find_least(object, start); 1863 1864 /* 1865 * Here, the variable "p" is either (1) the page with the least pindex 1866 * greater than or equal to the parameter "start" or (2) NULL. 1867 */ 1868 for (; p != NULL && (p->pindex < end || end == 0); p = next) { 1869 next = TAILQ_NEXT(p, listq); 1870 1871 /* 1872 * If the page is wired for any reason besides the existence 1873 * of managed, wired mappings, then it cannot be freed. For 1874 * example, fictitious pages, which represent device memory, 1875 * are inherently wired and cannot be freed. They can, 1876 * however, be invalidated if the option OBJPR_CLEANONLY is 1877 * not specified. 1878 */ 1879 vm_page_lock(p); 1880 if ((wirings = p->wire_count) != 0 && 1881 (wirings = pmap_page_wired_mappings(p)) != p->wire_count) { 1882 if ((options & OBJPR_NOTMAPPED) == 0) { 1883 pmap_remove_all(p); 1884 /* Account for removal of wired mappings. */ 1885 if (wirings != 0) 1886 p->wire_count -= wirings; 1887 } 1888 if ((options & OBJPR_CLEANONLY) == 0) { 1889 p->valid = 0; 1890 vm_page_undirty(p); 1891 } 1892 vm_page_unlock(p); 1893 continue; 1894 } 1895 if (vm_page_sleep_if_busy(p, TRUE, "vmopar")) 1896 goto again; 1897 KASSERT((p->flags & PG_FICTITIOUS) == 0, 1898 ("vm_object_page_remove: page %p is fictitious", p)); 1899 if ((options & OBJPR_CLEANONLY) != 0 && p->valid != 0) { 1900 if ((options & OBJPR_NOTMAPPED) == 0) 1901 pmap_remove_write(p); 1902 if (p->dirty) { 1903 vm_page_unlock(p); 1904 continue; 1905 } 1906 } 1907 if ((options & OBJPR_NOTMAPPED) == 0) { 1908 pmap_remove_all(p); 1909 /* Account for removal of wired mappings. */ 1910 if (wirings != 0) { 1911 KASSERT(p->wire_count == wirings, 1912 ("inconsistent wire count %d %d %p", 1913 p->wire_count, wirings, p)); 1914 p->wire_count = 0; 1915 atomic_subtract_int(&cnt.v_wire_count, 1); 1916 } 1917 } 1918 vm_page_free(p); 1919 vm_page_unlock(p); 1920 } 1921 vm_object_pip_wakeup(object); 1922skipmemq: 1923 if (__predict_false(object->cache != NULL)) 1924 vm_page_cache_free(object, start, end); 1925} 1926 1927/* 1928 * vm_object_page_cache: 1929 * 1930 * For the given object, attempt to move the specified clean 1931 * pages to the cache queue. If a page is wired for any reason, 1932 * then it will not be changed. Pages are specified by the given 1933 * range ["start", "end"). As a special case, if "end" is zero, 1934 * then the range extends from "start" to the end of the object. 1935 * Any mappings to the specified pages are removed before the 1936 * pages are moved to the cache queue. 1937 * 1938 * This operation should only be performed on objects that 1939 * contain non-fictitious, managed pages. 1940 * 1941 * The object must be locked. 1942 */ 1943void 1944vm_object_page_cache(vm_object_t object, vm_pindex_t start, vm_pindex_t end) 1945{ 1946 struct mtx *mtx, *new_mtx; 1947 vm_page_t p, next; 1948 1949 VM_OBJECT_LOCK_ASSERT(object, MA_OWNED); 1950 KASSERT((object->flags & (OBJ_FICTITIOUS | OBJ_UNMANAGED)) == 0, 1951 ("vm_object_page_cache: illegal object %p", object)); 1952 if (object->resident_page_count == 0) 1953 return; 1954 p = vm_page_find_least(object, start); 1955 1956 /* 1957 * Here, the variable "p" is either (1) the page with the least pindex 1958 * greater than or equal to the parameter "start" or (2) NULL. 1959 */ 1960 mtx = NULL; 1961 for (; p != NULL && (p->pindex < end || end == 0); p = next) { 1962 next = TAILQ_NEXT(p, listq); 1963 1964 /* 1965 * Avoid releasing and reacquiring the same page lock. 1966 */ 1967 new_mtx = vm_page_lockptr(p); 1968 if (mtx != new_mtx) { 1969 if (mtx != NULL) 1970 mtx_unlock(mtx); 1971 mtx = new_mtx; 1972 mtx_lock(mtx); 1973 } 1974 vm_page_try_to_cache(p); 1975 } 1976 if (mtx != NULL) 1977 mtx_unlock(mtx); 1978} 1979 1980/* 1981 * Populate the specified range of the object with valid pages. Returns 1982 * TRUE if the range is successfully populated and FALSE otherwise. 1983 * 1984 * Note: This function should be optimized to pass a larger array of 1985 * pages to vm_pager_get_pages() before it is applied to a non- 1986 * OBJT_DEVICE object. 1987 * 1988 * The object must be locked. 1989 */ 1990boolean_t 1991vm_object_populate(vm_object_t object, vm_pindex_t start, vm_pindex_t end) 1992{ 1993 vm_page_t m, ma[1]; 1994 vm_pindex_t pindex; 1995 int rv; 1996 1997 VM_OBJECT_LOCK_ASSERT(object, MA_OWNED); 1998 for (pindex = start; pindex < end; pindex++) { 1999 m = vm_page_grab(object, pindex, VM_ALLOC_NORMAL | 2000 VM_ALLOC_RETRY); 2001 if (m->valid != VM_PAGE_BITS_ALL) { 2002 ma[0] = m; 2003 rv = vm_pager_get_pages(object, ma, 1, 0); 2004 m = vm_page_lookup(object, pindex); 2005 if (m == NULL) 2006 break; 2007 if (rv != VM_PAGER_OK) { 2008 vm_page_lock(m); 2009 vm_page_free(m); 2010 vm_page_unlock(m); 2011 break; 2012 } 2013 } 2014 /* 2015 * Keep "m" busy because a subsequent iteration may unlock 2016 * the object. 2017 */ 2018 } 2019 if (pindex > start) { 2020 m = vm_page_lookup(object, start); 2021 while (m != NULL && m->pindex < pindex) { 2022 vm_page_wakeup(m); 2023 m = TAILQ_NEXT(m, listq); 2024 } 2025 } 2026 return (pindex == end); 2027} 2028 2029/* 2030 * Routine: vm_object_coalesce 2031 * Function: Coalesces two objects backing up adjoining 2032 * regions of memory into a single object. 2033 * 2034 * returns TRUE if objects were combined. 2035 * 2036 * NOTE: Only works at the moment if the second object is NULL - 2037 * if it's not, which object do we lock first? 2038 * 2039 * Parameters: 2040 * prev_object First object to coalesce 2041 * prev_offset Offset into prev_object 2042 * prev_size Size of reference to prev_object 2043 * next_size Size of reference to the second object 2044 * reserved Indicator that extension region has 2045 * swap accounted for 2046 * 2047 * Conditions: 2048 * The object must *not* be locked. 2049 */ 2050boolean_t 2051vm_object_coalesce(vm_object_t prev_object, vm_ooffset_t prev_offset, 2052 vm_size_t prev_size, vm_size_t next_size, boolean_t reserved) 2053{ 2054 vm_pindex_t next_pindex; 2055 2056 if (prev_object == NULL) 2057 return (TRUE); 2058 VM_OBJECT_LOCK(prev_object); 2059 if (prev_object->type != OBJT_DEFAULT && 2060 prev_object->type != OBJT_SWAP) { 2061 VM_OBJECT_UNLOCK(prev_object); 2062 return (FALSE); 2063 } 2064 2065 /* 2066 * Try to collapse the object first 2067 */ 2068 vm_object_collapse(prev_object); 2069 2070 /* 2071 * Can't coalesce if: . more than one reference . paged out . shadows 2072 * another object . has a copy elsewhere (any of which mean that the 2073 * pages not mapped to prev_entry may be in use anyway) 2074 */ 2075 if (prev_object->backing_object != NULL) { 2076 VM_OBJECT_UNLOCK(prev_object); 2077 return (FALSE); 2078 } 2079 2080 prev_size >>= PAGE_SHIFT; 2081 next_size >>= PAGE_SHIFT; 2082 next_pindex = OFF_TO_IDX(prev_offset) + prev_size; 2083 2084 if ((prev_object->ref_count > 1) && 2085 (prev_object->size != next_pindex)) { 2086 VM_OBJECT_UNLOCK(prev_object); 2087 return (FALSE); 2088 } 2089 2090 /* 2091 * Account for the charge. 2092 */ 2093 if (prev_object->cred != NULL) { 2094 2095 /* 2096 * If prev_object was charged, then this mapping, 2097 * althought not charged now, may become writable 2098 * later. Non-NULL cred in the object would prevent 2099 * swap reservation during enabling of the write 2100 * access, so reserve swap now. Failed reservation 2101 * cause allocation of the separate object for the map 2102 * entry, and swap reservation for this entry is 2103 * managed in appropriate time. 2104 */ 2105 if (!reserved && !swap_reserve_by_cred(ptoa(next_size), 2106 prev_object->cred)) { 2107 return (FALSE); 2108 } 2109 prev_object->charge += ptoa(next_size); 2110 } 2111 2112 /* 2113 * Remove any pages that may still be in the object from a previous 2114 * deallocation. 2115 */ 2116 if (next_pindex < prev_object->size) { 2117 vm_object_page_remove(prev_object, next_pindex, next_pindex + 2118 next_size, 0); 2119 if (prev_object->type == OBJT_SWAP) 2120 swap_pager_freespace(prev_object, 2121 next_pindex, next_size); 2122#if 0 2123 if (prev_object->cred != NULL) { 2124 KASSERT(prev_object->charge >= 2125 ptoa(prev_object->size - next_pindex), 2126 ("object %p overcharged 1 %jx %jx", prev_object, 2127 (uintmax_t)next_pindex, (uintmax_t)next_size)); 2128 prev_object->charge -= ptoa(prev_object->size - 2129 next_pindex); 2130 } 2131#endif 2132 } 2133 2134 /* 2135 * Extend the object if necessary. 2136 */ 2137 if (next_pindex + next_size > prev_object->size) 2138 prev_object->size = next_pindex + next_size; 2139 2140 VM_OBJECT_UNLOCK(prev_object); 2141 return (TRUE); 2142} 2143 2144void 2145vm_object_set_writeable_dirty(vm_object_t object) 2146{ 2147 2148 VM_OBJECT_LOCK_ASSERT(object, MA_OWNED); 2149 if (object->type != OBJT_VNODE) 2150 return; 2151 object->generation++; 2152 if ((object->flags & OBJ_MIGHTBEDIRTY) != 0) 2153 return; 2154 vm_object_set_flag(object, OBJ_MIGHTBEDIRTY); 2155} 2156 2157#include "opt_ddb.h" 2158#ifdef DDB 2159#include <sys/kernel.h> 2160 2161#include <sys/cons.h> 2162 2163#include <ddb/ddb.h> 2164 2165static int 2166_vm_object_in_map(vm_map_t map, vm_object_t object, vm_map_entry_t entry) 2167{ 2168 vm_map_t tmpm; 2169 vm_map_entry_t tmpe; 2170 vm_object_t obj; 2171 int entcount; 2172 2173 if (map == 0) 2174 return 0; 2175 2176 if (entry == 0) { 2177 tmpe = map->header.next; 2178 entcount = map->nentries; 2179 while (entcount-- && (tmpe != &map->header)) { 2180 if (_vm_object_in_map(map, object, tmpe)) { 2181 return 1; 2182 } 2183 tmpe = tmpe->next; 2184 } 2185 } else if (entry->eflags & MAP_ENTRY_IS_SUB_MAP) { 2186 tmpm = entry->object.sub_map; 2187 tmpe = tmpm->header.next; 2188 entcount = tmpm->nentries; 2189 while (entcount-- && tmpe != &tmpm->header) { 2190 if (_vm_object_in_map(tmpm, object, tmpe)) { 2191 return 1; 2192 } 2193 tmpe = tmpe->next; 2194 } 2195 } else if ((obj = entry->object.vm_object) != NULL) { 2196 for (; obj; obj = obj->backing_object) 2197 if (obj == object) { 2198 return 1; 2199 } 2200 } 2201 return 0; 2202} 2203 2204static int 2205vm_object_in_map(vm_object_t object) 2206{ 2207 struct proc *p; 2208 2209 /* sx_slock(&allproc_lock); */ 2210 FOREACH_PROC_IN_SYSTEM(p) { 2211 if (!p->p_vmspace /* || (p->p_flag & (P_SYSTEM|P_WEXIT)) */) 2212 continue; 2213 if (_vm_object_in_map(&p->p_vmspace->vm_map, object, 0)) { 2214 /* sx_sunlock(&allproc_lock); */ 2215 return 1; 2216 } 2217 } 2218 /* sx_sunlock(&allproc_lock); */ 2219 if (_vm_object_in_map(kernel_map, object, 0)) 2220 return 1; 2221 if (_vm_object_in_map(kmem_map, object, 0)) 2222 return 1; 2223 if (_vm_object_in_map(pager_map, object, 0)) 2224 return 1; 2225 if (_vm_object_in_map(buffer_map, object, 0)) 2226 return 1; 2227 return 0; 2228} 2229 2230DB_SHOW_COMMAND(vmochk, vm_object_check) 2231{ 2232 vm_object_t object; 2233 2234 /* 2235 * make sure that internal objs are in a map somewhere 2236 * and none have zero ref counts. 2237 */ 2238 TAILQ_FOREACH(object, &vm_object_list, object_list) { 2239 if (object->handle == NULL && 2240 (object->type == OBJT_DEFAULT || object->type == OBJT_SWAP)) { 2241 if (object->ref_count == 0) { 2242 db_printf("vmochk: internal obj has zero ref count: %ld\n", 2243 (long)object->size); 2244 } 2245 if (!vm_object_in_map(object)) { 2246 db_printf( 2247 "vmochk: internal obj is not in a map: " 2248 "ref: %d, size: %lu: 0x%lx, backing_object: %p\n", 2249 object->ref_count, (u_long)object->size, 2250 (u_long)object->size, 2251 (void *)object->backing_object); 2252 } 2253 } 2254 } 2255} 2256 2257/* 2258 * vm_object_print: [ debug ] 2259 */ 2260DB_SHOW_COMMAND(object, vm_object_print_static) 2261{ 2262 /* XXX convert args. */ 2263 vm_object_t object = (vm_object_t)addr; 2264 boolean_t full = have_addr; 2265 2266 vm_page_t p; 2267 2268 /* XXX count is an (unused) arg. Avoid shadowing it. */ 2269#define count was_count 2270 2271 int count; 2272 2273 if (object == NULL) 2274 return; 2275 2276 db_iprintf( 2277 "Object %p: type=%d, size=0x%jx, res=%d, ref=%d, flags=0x%x ruid %d charge %jx\n", 2278 object, (int)object->type, (uintmax_t)object->size, 2279 object->resident_page_count, object->ref_count, object->flags, 2280 object->cred ? object->cred->cr_ruid : -1, (uintmax_t)object->charge); 2281 db_iprintf(" sref=%d, backing_object(%d)=(%p)+0x%jx\n", 2282 object->shadow_count, 2283 object->backing_object ? object->backing_object->ref_count : 0, 2284 object->backing_object, (uintmax_t)object->backing_object_offset); 2285 2286 if (!full) 2287 return; 2288 2289 db_indent += 2; 2290 count = 0; 2291 TAILQ_FOREACH(p, &object->memq, listq) { 2292 if (count == 0) 2293 db_iprintf("memory:="); 2294 else if (count == 6) { 2295 db_printf("\n"); 2296 db_iprintf(" ..."); 2297 count = 0; 2298 } else 2299 db_printf(","); 2300 count++; 2301 2302 db_printf("(off=0x%jx,page=0x%jx)", 2303 (uintmax_t)p->pindex, (uintmax_t)VM_PAGE_TO_PHYS(p)); 2304 } 2305 if (count != 0) 2306 db_printf("\n"); 2307 db_indent -= 2; 2308} 2309 2310/* XXX. */ 2311#undef count 2312 2313/* XXX need this non-static entry for calling from vm_map_print. */ 2314void 2315vm_object_print( 2316 /* db_expr_t */ long addr, 2317 boolean_t have_addr, 2318 /* db_expr_t */ long count, 2319 char *modif) 2320{ 2321 vm_object_print_static(addr, have_addr, count, modif); 2322} 2323 2324DB_SHOW_COMMAND(vmopag, vm_object_print_pages) 2325{ 2326 vm_object_t object; 2327 vm_pindex_t fidx; 2328 vm_paddr_t pa; 2329 vm_page_t m, prev_m; 2330 int rcount, nl, c; 2331 2332 nl = 0; 2333 TAILQ_FOREACH(object, &vm_object_list, object_list) { 2334 db_printf("new object: %p\n", (void *)object); 2335 if (nl > 18) { 2336 c = cngetc(); 2337 if (c != ' ') 2338 return; 2339 nl = 0; 2340 } 2341 nl++; 2342 rcount = 0; 2343 fidx = 0; 2344 pa = -1; 2345 TAILQ_FOREACH(m, &object->memq, listq) { 2346 if (m->pindex > 128) 2347 break; 2348 if ((prev_m = TAILQ_PREV(m, pglist, listq)) != NULL && 2349 prev_m->pindex + 1 != m->pindex) { 2350 if (rcount) { 2351 db_printf(" index(%ld)run(%d)pa(0x%lx)\n", 2352 (long)fidx, rcount, (long)pa); 2353 if (nl > 18) { 2354 c = cngetc(); 2355 if (c != ' ') 2356 return; 2357 nl = 0; 2358 } 2359 nl++; 2360 rcount = 0; 2361 } 2362 } 2363 if (rcount && 2364 (VM_PAGE_TO_PHYS(m) == pa + rcount * PAGE_SIZE)) { 2365 ++rcount; 2366 continue; 2367 } 2368 if (rcount) { 2369 db_printf(" index(%ld)run(%d)pa(0x%lx)\n", 2370 (long)fidx, rcount, (long)pa); 2371 if (nl > 18) { 2372 c = cngetc(); 2373 if (c != ' ') 2374 return; 2375 nl = 0; 2376 } 2377 nl++; 2378 } 2379 fidx = m->pindex; 2380 pa = VM_PAGE_TO_PHYS(m); 2381 rcount = 1; 2382 } 2383 if (rcount) { 2384 db_printf(" index(%ld)run(%d)pa(0x%lx)\n", 2385 (long)fidx, rcount, (long)pa); 2386 if (nl > 18) { 2387 c = cngetc(); 2388 if (c != ' ') 2389 return; 2390 nl = 0; 2391 } 2392 nl++; 2393 } 2394 } 2395} 2396#endif /* DDB */ 2397