1 /*- 2 * Copyright (c) 1991 Regents of the University of California. 3 * All rights reserved. 4 * Copyright (c) 1998 Matthew Dillon. All Rights Reserved. 5 * 6 * This code is derived from software contributed to Berkeley by 7 * The Mach Operating System project at Carnegie-Mellon University. 8 * 9 * Redistribution and use in source and binary forms, with or without 10 * modification, are permitted provided that the following conditions 11 * are met: 12 * 1. Redistributions of source code must retain the above copyright 13 * notice, this list of conditions and the following disclaimer. 14 * 2. Redistributions in binary form must reproduce the above copyright 15 * notice, this list of conditions and the following disclaimer in the 16 * documentation and/or other materials provided with the distribution. 17 * 4. Neither the name of the University nor the names of its contributors 18 * may be used to endorse or promote products derived from this software 19 * without specific prior written permission. 20 * 21 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 22 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 23 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 24 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 25 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 26 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 27 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 28 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 29 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 30 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 31 * SUCH DAMAGE. 32 * 33 * from: @(#)vm_page.c 7.4 (Berkeley) 5/7/91 34 */ 35 36 /*- 37 * Copyright (c) 1987, 1990 Carnegie-Mellon University. 38 * All rights reserved. 39 * 40 * Authors: Avadis Tevanian, Jr., Michael Wayne Young 41 * 42 * Permission to use, copy, modify and distribute this software and 43 * its documentation is hereby granted, provided that both the copyright 44 * notice and this permission notice appear in all copies of the 45 * software, derivative works or modified versions, and any portions 46 * thereof, and that both notices appear in supporting documentation. 47 * 48 * CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS" 49 * CONDITION. CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND 50 * FOR ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE. 51 * 52 * Carnegie Mellon requests users of this software to return to 53 * 54 * Software Distribution Coordinator or Software.Distribution@CS.CMU.EDU 55 * School of Computer Science 56 * Carnegie Mellon University 57 * Pittsburgh PA 15213-3890 58 * 59 * any improvements or extensions that they make and grant Carnegie the 60 * rights to redistribute these changes. 61 */ 62 63 /* 64 * GENERAL RULES ON VM_PAGE MANIPULATION 65 * 66 * - a pageq mutex is required when adding or removing a page from a 67 * page queue (vm_page_queue[]), regardless of other mutexes or the 68 * busy state of a page. 69 * 70 * - The object mutex is held when inserting or removing 71 * pages from an object (vm_page_insert() or vm_page_remove()). 72 * 73 */ 74 75 /* 76 * Resident memory management module. 77 */ 78 79 #include <sys/cdefs.h> 80 __FBSDID("$FreeBSD$"); 81 82 #include "opt_vm.h" 83 84 #include <sys/param.h> 85 #include <sys/systm.h> 86 #include <sys/lock.h> 87 #include <sys/kernel.h> 88 #include <sys/limits.h> 89 #include <sys/malloc.h> 90 #include <sys/msgbuf.h> 91 #include <sys/mutex.h> 92 #include <sys/proc.h> 93 #include <sys/sysctl.h> 94 #include <sys/vmmeter.h> 95 #include <sys/vnode.h> 96 97 #include <vm/vm.h> 98 #include <vm/pmap.h> 99 #include <vm/vm_param.h> 100 #include <vm/vm_kern.h> 101 #include <vm/vm_object.h> 102 #include <vm/vm_page.h> 103 #include <vm/vm_pageout.h> 104 #include <vm/vm_pager.h> 105 #include <vm/vm_phys.h> 106 #include <vm/vm_reserv.h> 107 #include <vm/vm_extern.h> 108 #include <vm/uma.h> 109 #include <vm/uma_int.h> 110 111 #include <machine/md_var.h> 112 113 /* 114 * Associated with page of user-allocatable memory is a 115 * page structure. 116 */ 117 118 struct vpgqueues vm_page_queues[PQ_COUNT]; 119 struct mtx_padalign vm_page_queue_mtx; 120 struct mtx_padalign vm_page_queue_free_mtx; 121 122 struct mtx_padalign pa_lock[PA_LOCK_COUNT]; 123 124 vm_page_t vm_page_array; 125 long vm_page_array_size; 126 long first_page; 127 int vm_page_zero_count; 128 129 static int boot_pages = UMA_BOOT_PAGES; 130 TUNABLE_INT("vm.boot_pages", &boot_pages); 131 SYSCTL_INT(_vm, OID_AUTO, boot_pages, CTLFLAG_RD, &boot_pages, 0, 132 "number of pages allocated for bootstrapping the VM system"); 133 134 static int pa_tryrelock_restart; 135 SYSCTL_INT(_vm, OID_AUTO, tryrelock_restart, CTLFLAG_RD, 136 &pa_tryrelock_restart, 0, "Number of tryrelock restarts"); 137 138 static uma_zone_t fakepg_zone; 139 140 static struct vnode *vm_page_alloc_init(vm_page_t m); 141 static void vm_page_clear_dirty_mask(vm_page_t m, vm_page_bits_t pagebits); 142 static void vm_page_queue_remove(int queue, vm_page_t m); 143 static void vm_page_enqueue(int queue, vm_page_t m); 144 static void vm_page_init_fakepg(void *dummy); 145 146 SYSINIT(vm_page, SI_SUB_VM, SI_ORDER_SECOND, vm_page_init_fakepg, NULL); 147 148 static void 149 vm_page_init_fakepg(void *dummy) 150 { 151 152 fakepg_zone = uma_zcreate("fakepg", sizeof(struct vm_page), NULL, NULL, 153 NULL, NULL, UMA_ALIGN_PTR, UMA_ZONE_NOFREE | UMA_ZONE_VM); 154 } 155 156 /* Make sure that u_long is at least 64 bits when PAGE_SIZE is 32K. */ 157 #if PAGE_SIZE == 32768 158 #ifdef CTASSERT 159 CTASSERT(sizeof(u_long) >= 8); 160 #endif 161 #endif 162 163 /* 164 * Try to acquire a physical address lock while a pmap is locked. If we 165 * fail to trylock we unlock and lock the pmap directly and cache the 166 * locked pa in *locked. The caller should then restart their loop in case 167 * the virtual to physical mapping has changed. 168 */ 169 int 170 vm_page_pa_tryrelock(pmap_t pmap, vm_paddr_t pa, vm_paddr_t *locked) 171 { 172 vm_paddr_t lockpa; 173 174 lockpa = *locked; 175 *locked = pa; 176 if (lockpa) { 177 PA_LOCK_ASSERT(lockpa, MA_OWNED); 178 if (PA_LOCKPTR(pa) == PA_LOCKPTR(lockpa)) 179 return (0); 180 PA_UNLOCK(lockpa); 181 } 182 if (PA_TRYLOCK(pa)) 183 return (0); 184 PMAP_UNLOCK(pmap); 185 atomic_add_int(&pa_tryrelock_restart, 1); 186 PA_LOCK(pa); 187 PMAP_LOCK(pmap); 188 return (EAGAIN); 189 } 190 191 /* 192 * vm_set_page_size: 193 * 194 * Sets the page size, perhaps based upon the memory 195 * size. Must be called before any use of page-size 196 * dependent functions. 197 */ 198 void 199 vm_set_page_size(void) 200 { 201 if (cnt.v_page_size == 0) 202 cnt.v_page_size = PAGE_SIZE; 203 if (((cnt.v_page_size - 1) & cnt.v_page_size) != 0) 204 panic("vm_set_page_size: page size not a power of two"); 205 } 206 207 /* 208 * vm_page_blacklist_lookup: 209 * 210 * See if a physical address in this page has been listed 211 * in the blacklist tunable. Entries in the tunable are 212 * separated by spaces or commas. If an invalid integer is 213 * encountered then the rest of the string is skipped. 214 */ 215 static int 216 vm_page_blacklist_lookup(char *list, vm_paddr_t pa) 217 { 218 vm_paddr_t bad; 219 char *cp, *pos; 220 221 for (pos = list; *pos != '\0'; pos = cp) { 222 bad = strtoq(pos, &cp, 0); 223 if (*cp != '\0') { 224 if (*cp == ' ' || *cp == ',') { 225 cp++; 226 if (cp == pos) 227 continue; 228 } else 229 break; 230 } 231 if (pa == trunc_page(bad)) 232 return (1); 233 } 234 return (0); 235 } 236 237 /* 238 * vm_page_startup: 239 * 240 * Initializes the resident memory module. 241 * 242 * Allocates memory for the page cells, and 243 * for the object/offset-to-page hash table headers. 244 * Each page cell is initialized and placed on the free list. 245 */ 246 vm_offset_t 247 vm_page_startup(vm_offset_t vaddr) 248 { 249 vm_offset_t mapped; 250 vm_paddr_t page_range; 251 vm_paddr_t new_end; 252 int i; 253 vm_paddr_t pa; 254 vm_paddr_t last_pa; 255 char *list; 256 257 /* the biggest memory array is the second group of pages */ 258 vm_paddr_t end; 259 vm_paddr_t biggestsize; 260 vm_paddr_t low_water, high_water; 261 int biggestone; 262 263 biggestsize = 0; 264 biggestone = 0; 265 vaddr = round_page(vaddr); 266 267 for (i = 0; phys_avail[i + 1]; i += 2) { 268 phys_avail[i] = round_page(phys_avail[i]); 269 phys_avail[i + 1] = trunc_page(phys_avail[i + 1]); 270 } 271 272 low_water = phys_avail[0]; 273 high_water = phys_avail[1]; 274 275 for (i = 0; phys_avail[i + 1]; i += 2) { 276 vm_paddr_t size = phys_avail[i + 1] - phys_avail[i]; 277 278 if (size > biggestsize) { 279 biggestone = i; 280 biggestsize = size; 281 } 282 if (phys_avail[i] < low_water) 283 low_water = phys_avail[i]; 284 if (phys_avail[i + 1] > high_water) 285 high_water = phys_avail[i + 1]; 286 } 287 288 #ifdef XEN 289 low_water = 0; 290 #endif 291 292 end = phys_avail[biggestone+1]; 293 294 /* 295 * Initialize the page and queue locks. 296 */ 297 mtx_init(&vm_page_queue_mtx, "vm page queue", NULL, MTX_DEF | 298 MTX_RECURSE); 299 mtx_init(&vm_page_queue_free_mtx, "vm page free queue", NULL, MTX_DEF); 300 for (i = 0; i < PA_LOCK_COUNT; i++) 301 mtx_init(&pa_lock[i], "vm page", NULL, MTX_DEF); 302 303 /* 304 * Initialize the queue headers for the hold queue, the active queue, 305 * and the inactive queue. 306 */ 307 for (i = 0; i < PQ_COUNT; i++) 308 TAILQ_INIT(&vm_page_queues[i].pl); 309 vm_page_queues[PQ_INACTIVE].cnt = &cnt.v_inactive_count; 310 vm_page_queues[PQ_ACTIVE].cnt = &cnt.v_active_count; 311 312 /* 313 * Allocate memory for use when boot strapping the kernel memory 314 * allocator. 315 */ 316 new_end = end - (boot_pages * UMA_SLAB_SIZE); 317 new_end = trunc_page(new_end); 318 mapped = pmap_map(&vaddr, new_end, end, 319 VM_PROT_READ | VM_PROT_WRITE); 320 bzero((void *)mapped, end - new_end); 321 uma_startup((void *)mapped, boot_pages); 322 323 #if defined(__amd64__) || defined(__i386__) || defined(__arm__) || \ 324 defined(__mips__) 325 /* 326 * Allocate a bitmap to indicate that a random physical page 327 * needs to be included in a minidump. 328 * 329 * The amd64 port needs this to indicate which direct map pages 330 * need to be dumped, via calls to dump_add_page()/dump_drop_page(). 331 * 332 * However, i386 still needs this workspace internally within the 333 * minidump code. In theory, they are not needed on i386, but are 334 * included should the sf_buf code decide to use them. 335 */ 336 last_pa = 0; 337 for (i = 0; dump_avail[i + 1] != 0; i += 2) 338 if (dump_avail[i + 1] > last_pa) 339 last_pa = dump_avail[i + 1]; 340 page_range = last_pa / PAGE_SIZE; 341 vm_page_dump_size = round_page(roundup2(page_range, NBBY) / NBBY); 342 new_end -= vm_page_dump_size; 343 vm_page_dump = (void *)(uintptr_t)pmap_map(&vaddr, new_end, 344 new_end + vm_page_dump_size, VM_PROT_READ | VM_PROT_WRITE); 345 bzero((void *)vm_page_dump, vm_page_dump_size); 346 #endif 347 #ifdef __amd64__ 348 /* 349 * Request that the physical pages underlying the message buffer be 350 * included in a crash dump. Since the message buffer is accessed 351 * through the direct map, they are not automatically included. 352 */ 353 pa = DMAP_TO_PHYS((vm_offset_t)msgbufp->msg_ptr); 354 last_pa = pa + round_page(msgbufsize); 355 while (pa < last_pa) { 356 dump_add_page(pa); 357 pa += PAGE_SIZE; 358 } 359 #endif 360 /* 361 * Compute the number of pages of memory that will be available for 362 * use (taking into account the overhead of a page structure per 363 * page). 364 */ 365 first_page = low_water / PAGE_SIZE; 366 #ifdef VM_PHYSSEG_SPARSE 367 page_range = 0; 368 for (i = 0; phys_avail[i + 1] != 0; i += 2) 369 page_range += atop(phys_avail[i + 1] - phys_avail[i]); 370 #elif defined(VM_PHYSSEG_DENSE) 371 page_range = high_water / PAGE_SIZE - first_page; 372 #else 373 #error "Either VM_PHYSSEG_DENSE or VM_PHYSSEG_SPARSE must be defined." 374 #endif 375 end = new_end; 376 377 /* 378 * Reserve an unmapped guard page to trap access to vm_page_array[-1]. 379 */ 380 vaddr += PAGE_SIZE; 381 382 /* 383 * Initialize the mem entry structures now, and put them in the free 384 * queue. 385 */ 386 new_end = trunc_page(end - page_range * sizeof(struct vm_page)); 387 mapped = pmap_map(&vaddr, new_end, end, 388 VM_PROT_READ | VM_PROT_WRITE); 389 vm_page_array = (vm_page_t) mapped; 390 #if VM_NRESERVLEVEL > 0 391 /* 392 * Allocate memory for the reservation management system's data 393 * structures. 394 */ 395 new_end = vm_reserv_startup(&vaddr, new_end, high_water); 396 #endif 397 #if defined(__amd64__) || defined(__mips__) 398 /* 399 * pmap_map on amd64 and mips can come out of the direct-map, not kvm 400 * like i386, so the pages must be tracked for a crashdump to include 401 * this data. This includes the vm_page_array and the early UMA 402 * bootstrap pages. 403 */ 404 for (pa = new_end; pa < phys_avail[biggestone + 1]; pa += PAGE_SIZE) 405 dump_add_page(pa); 406 #endif 407 phys_avail[biggestone + 1] = new_end; 408 409 /* 410 * Clear all of the page structures 411 */ 412 bzero((caddr_t) vm_page_array, page_range * sizeof(struct vm_page)); 413 for (i = 0; i < page_range; i++) 414 vm_page_array[i].order = VM_NFREEORDER; 415 vm_page_array_size = page_range; 416 417 /* 418 * Initialize the physical memory allocator. 419 */ 420 vm_phys_init(); 421 422 /* 423 * Add every available physical page that is not blacklisted to 424 * the free lists. 425 */ 426 cnt.v_page_count = 0; 427 cnt.v_free_count = 0; 428 list = getenv("vm.blacklist"); 429 for (i = 0; phys_avail[i + 1] != 0; i += 2) { 430 pa = phys_avail[i]; 431 last_pa = phys_avail[i + 1]; 432 while (pa < last_pa) { 433 if (list != NULL && 434 vm_page_blacklist_lookup(list, pa)) 435 printf("Skipping page with pa 0x%jx\n", 436 (uintmax_t)pa); 437 else 438 vm_phys_add_page(pa); 439 pa += PAGE_SIZE; 440 } 441 } 442 freeenv(list); 443 #if VM_NRESERVLEVEL > 0 444 /* 445 * Initialize the reservation management system. 446 */ 447 vm_reserv_init(); 448 #endif 449 return (vaddr); 450 } 451 452 void 453 vm_page_reference(vm_page_t m) 454 { 455 456 vm_page_aflag_set(m, PGA_REFERENCED); 457 } 458 459 void 460 vm_page_busy(vm_page_t m) 461 { 462 463 VM_OBJECT_LOCK_ASSERT(m->object, MA_OWNED); 464 KASSERT((m->oflags & VPO_BUSY) == 0, 465 ("vm_page_busy: page already busy!!!")); 466 m->oflags |= VPO_BUSY; 467 } 468 469 /* 470 * vm_page_flash: 471 * 472 * wakeup anyone waiting for the page. 473 */ 474 void 475 vm_page_flash(vm_page_t m) 476 { 477 478 VM_OBJECT_LOCK_ASSERT(m->object, MA_OWNED); 479 if (m->oflags & VPO_WANTED) { 480 m->oflags &= ~VPO_WANTED; 481 wakeup(m); 482 } 483 } 484 485 /* 486 * vm_page_wakeup: 487 * 488 * clear the VPO_BUSY flag and wakeup anyone waiting for the 489 * page. 490 * 491 */ 492 void 493 vm_page_wakeup(vm_page_t m) 494 { 495 496 VM_OBJECT_LOCK_ASSERT(m->object, MA_OWNED); 497 KASSERT(m->oflags & VPO_BUSY, ("vm_page_wakeup: page not busy!!!")); 498 m->oflags &= ~VPO_BUSY; 499 vm_page_flash(m); 500 } 501 502 void 503 vm_page_io_start(vm_page_t m) 504 { 505 506 VM_OBJECT_LOCK_ASSERT(m->object, MA_OWNED); 507 m->busy++; 508 } 509 510 void 511 vm_page_io_finish(vm_page_t m) 512 { 513 514 VM_OBJECT_LOCK_ASSERT(m->object, MA_OWNED); 515 KASSERT(m->busy > 0, ("vm_page_io_finish: page %p is not busy", m)); 516 m->busy--; 517 if (m->busy == 0) 518 vm_page_flash(m); 519 } 520 521 /* 522 * Keep page from being freed by the page daemon 523 * much of the same effect as wiring, except much lower 524 * overhead and should be used only for *very* temporary 525 * holding ("wiring"). 526 */ 527 void 528 vm_page_hold(vm_page_t mem) 529 { 530 531 vm_page_lock_assert(mem, MA_OWNED); 532 mem->hold_count++; 533 } 534 535 void 536 vm_page_unhold(vm_page_t mem) 537 { 538 539 vm_page_lock_assert(mem, MA_OWNED); 540 --mem->hold_count; 541 KASSERT(mem->hold_count >= 0, ("vm_page_unhold: hold count < 0!!!")); 542 if (mem->hold_count == 0 && (mem->flags & PG_UNHOLDFREE) != 0) 543 vm_page_free_toq(mem); 544 } 545 546 /* 547 * vm_page_unhold_pages: 548 * 549 * Unhold each of the pages that is referenced by the given array. 550 */ 551 void 552 vm_page_unhold_pages(vm_page_t *ma, int count) 553 { 554 struct mtx *mtx, *new_mtx; 555 556 mtx = NULL; 557 for (; count != 0; count--) { 558 /* 559 * Avoid releasing and reacquiring the same page lock. 560 */ 561 new_mtx = vm_page_lockptr(*ma); 562 if (mtx != new_mtx) { 563 if (mtx != NULL) 564 mtx_unlock(mtx); 565 mtx = new_mtx; 566 mtx_lock(mtx); 567 } 568 vm_page_unhold(*ma); 569 ma++; 570 } 571 if (mtx != NULL) 572 mtx_unlock(mtx); 573 } 574 575 vm_page_t 576 PHYS_TO_VM_PAGE(vm_paddr_t pa) 577 { 578 vm_page_t m; 579 580 #ifdef VM_PHYSSEG_SPARSE 581 m = vm_phys_paddr_to_vm_page(pa); 582 if (m == NULL) 583 m = vm_phys_fictitious_to_vm_page(pa); 584 return (m); 585 #elif defined(VM_PHYSSEG_DENSE) 586 long pi; 587 588 pi = atop(pa); 589 if (pi >= first_page && (pi - first_page) < vm_page_array_size) { 590 m = &vm_page_array[pi - first_page]; 591 return (m); 592 } 593 return (vm_phys_fictitious_to_vm_page(pa)); 594 #else 595 #error "Either VM_PHYSSEG_DENSE or VM_PHYSSEG_SPARSE must be defined." 596 #endif 597 } 598 599 /* 600 * vm_page_getfake: 601 * 602 * Create a fictitious page with the specified physical address and 603 * memory attribute. The memory attribute is the only the machine- 604 * dependent aspect of a fictitious page that must be initialized. 605 */ 606 vm_page_t 607 vm_page_getfake(vm_paddr_t paddr, vm_memattr_t memattr) 608 { 609 vm_page_t m; 610 611 m = uma_zalloc(fakepg_zone, M_WAITOK | M_ZERO); 612 vm_page_initfake(m, paddr, memattr); 613 return (m); 614 } 615 616 void 617 vm_page_initfake(vm_page_t m, vm_paddr_t paddr, vm_memattr_t memattr) 618 { 619 620 if ((m->flags & PG_FICTITIOUS) != 0) { 621 /* 622 * The page's memattr might have changed since the 623 * previous initialization. Update the pmap to the 624 * new memattr. 625 */ 626 goto memattr; 627 } 628 m->phys_addr = paddr; 629 m->queue = PQ_NONE; 630 /* Fictitious pages don't use "segind". */ 631 m->flags = PG_FICTITIOUS; 632 /* Fictitious pages don't use "order" or "pool". */ 633 m->oflags = VPO_BUSY | VPO_UNMANAGED; 634 m->wire_count = 1; 635 memattr: 636 pmap_page_set_memattr(m, memattr); 637 } 638 639 /* 640 * vm_page_putfake: 641 * 642 * Release a fictitious page. 643 */ 644 void 645 vm_page_putfake(vm_page_t m) 646 { 647 648 KASSERT((m->oflags & VPO_UNMANAGED) != 0, ("managed %p", m)); 649 KASSERT((m->flags & PG_FICTITIOUS) != 0, 650 ("vm_page_putfake: bad page %p", m)); 651 uma_zfree(fakepg_zone, m); 652 } 653 654 /* 655 * vm_page_updatefake: 656 * 657 * Update the given fictitious page to the specified physical address and 658 * memory attribute. 659 */ 660 void 661 vm_page_updatefake(vm_page_t m, vm_paddr_t paddr, vm_memattr_t memattr) 662 { 663 664 KASSERT((m->flags & PG_FICTITIOUS) != 0, 665 ("vm_page_updatefake: bad page %p", m)); 666 m->phys_addr = paddr; 667 pmap_page_set_memattr(m, memattr); 668 } 669 670 /* 671 * vm_page_free: 672 * 673 * Free a page. 674 */ 675 void 676 vm_page_free(vm_page_t m) 677 { 678 679 m->flags &= ~PG_ZERO; 680 vm_page_free_toq(m); 681 } 682 683 /* 684 * vm_page_free_zero: 685 * 686 * Free a page to the zerod-pages queue 687 */ 688 void 689 vm_page_free_zero(vm_page_t m) 690 { 691 692 m->flags |= PG_ZERO; 693 vm_page_free_toq(m); 694 } 695 696 /* 697 * Unbusy and handle the page queueing for a page from the VOP_GETPAGES() 698 * array which is not the request page. 699 */ 700 void 701 vm_page_readahead_finish(vm_page_t m) 702 { 703 704 if (m->valid != 0) { 705 /* 706 * Since the page is not the requested page, whether 707 * it should be activated or deactivated is not 708 * obvious. Empirical results have shown that 709 * deactivating the page is usually the best choice, 710 * unless the page is wanted by another thread. 711 */ 712 if (m->oflags & VPO_WANTED) { 713 vm_page_lock(m); 714 vm_page_activate(m); 715 vm_page_unlock(m); 716 } else { 717 vm_page_lock(m); 718 vm_page_deactivate(m); 719 vm_page_unlock(m); 720 } 721 vm_page_wakeup(m); 722 } else { 723 /* 724 * Free the completely invalid page. Such page state 725 * occurs due to the short read operation which did 726 * not covered our page at all, or in case when a read 727 * error happens. 728 */ 729 vm_page_lock(m); 730 vm_page_free(m); 731 vm_page_unlock(m); 732 } 733 } 734 735 /* 736 * vm_page_sleep: 737 * 738 * Sleep and release the page lock. 739 * 740 * The object containing the given page must be locked. 741 */ 742 void 743 vm_page_sleep(vm_page_t m, const char *msg) 744 { 745 746 VM_OBJECT_LOCK_ASSERT(m->object, MA_OWNED); 747 if (mtx_owned(vm_page_lockptr(m))) 748 vm_page_unlock(m); 749 750 /* 751 * It's possible that while we sleep, the page will get 752 * unbusied and freed. If we are holding the object 753 * lock, we will assume we hold a reference to the object 754 * such that even if m->object changes, we can re-lock 755 * it. 756 */ 757 m->oflags |= VPO_WANTED; 758 msleep(m, VM_OBJECT_MTX(m->object), PVM, msg, 0); 759 } 760 761 /* 762 * vm_page_dirty_KBI: [ internal use only ] 763 * 764 * Set all bits in the page's dirty field. 765 * 766 * The object containing the specified page must be locked if the 767 * call is made from the machine-independent layer. 768 * 769 * See vm_page_clear_dirty_mask(). 770 * 771 * This function should only be called by vm_page_dirty(). 772 */ 773 void 774 vm_page_dirty_KBI(vm_page_t m) 775 { 776 777 /* These assertions refer to this operation by its public name. */ 778 KASSERT((m->flags & PG_CACHED) == 0, 779 ("vm_page_dirty: page in cache!")); 780 KASSERT(!VM_PAGE_IS_FREE(m), 781 ("vm_page_dirty: page is free!")); 782 KASSERT(m->valid == VM_PAGE_BITS_ALL, 783 ("vm_page_dirty: page is invalid!")); 784 m->dirty = VM_PAGE_BITS_ALL; 785 } 786 787 /* 788 * vm_page_splay: 789 * 790 * Implements Sleator and Tarjan's top-down splay algorithm. Returns 791 * the vm_page containing the given pindex. If, however, that 792 * pindex is not found in the vm_object, returns a vm_page that is 793 * adjacent to the pindex, coming before or after it. 794 */ 795 vm_page_t 796 vm_page_splay(vm_pindex_t pindex, vm_page_t root) 797 { 798 struct vm_page dummy; 799 vm_page_t lefttreemax, righttreemin, y; 800 801 if (root == NULL) 802 return (root); 803 lefttreemax = righttreemin = &dummy; 804 for (;; root = y) { 805 if (pindex < root->pindex) { 806 if ((y = root->left) == NULL) 807 break; 808 if (pindex < y->pindex) { 809 /* Rotate right. */ 810 root->left = y->right; 811 y->right = root; 812 root = y; 813 if ((y = root->left) == NULL) 814 break; 815 } 816 /* Link into the new root's right tree. */ 817 righttreemin->left = root; 818 righttreemin = root; 819 } else if (pindex > root->pindex) { 820 if ((y = root->right) == NULL) 821 break; 822 if (pindex > y->pindex) { 823 /* Rotate left. */ 824 root->right = y->left; 825 y->left = root; 826 root = y; 827 if ((y = root->right) == NULL) 828 break; 829 } 830 /* Link into the new root's left tree. */ 831 lefttreemax->right = root; 832 lefttreemax = root; 833 } else 834 break; 835 } 836 /* Assemble the new root. */ 837 lefttreemax->right = root->left; 838 righttreemin->left = root->right; 839 root->left = dummy.right; 840 root->right = dummy.left; 841 return (root); 842 } 843 844 /* 845 * vm_page_insert: [ internal use only ] 846 * 847 * Inserts the given mem entry into the object and object list. 848 * 849 * The pagetables are not updated but will presumably fault the page 850 * in if necessary, or if a kernel page the caller will at some point 851 * enter the page into the kernel's pmap. We are not allowed to sleep 852 * here so we *can't* do this anyway. 853 * 854 * The object must be locked. 855 */ 856 void 857 vm_page_insert(vm_page_t m, vm_object_t object, vm_pindex_t pindex) 858 { 859 vm_page_t root; 860 861 VM_OBJECT_LOCK_ASSERT(object, MA_OWNED); 862 if (m->object != NULL) 863 panic("vm_page_insert: page already inserted"); 864 865 /* 866 * Record the object/offset pair in this page 867 */ 868 m->object = object; 869 m->pindex = pindex; 870 871 /* 872 * Now link into the object's ordered list of backed pages. 873 */ 874 root = object->root; 875 if (root == NULL) { 876 m->left = NULL; 877 m->right = NULL; 878 TAILQ_INSERT_TAIL(&object->memq, m, listq); 879 } else { 880 root = vm_page_splay(pindex, root); 881 if (pindex < root->pindex) { 882 m->left = root->left; 883 m->right = root; 884 root->left = NULL; 885 TAILQ_INSERT_BEFORE(root, m, listq); 886 } else if (pindex == root->pindex) 887 panic("vm_page_insert: offset already allocated"); 888 else { 889 m->right = root->right; 890 m->left = root; 891 root->right = NULL; 892 TAILQ_INSERT_AFTER(&object->memq, root, m, listq); 893 } 894 } 895 object->root = m; 896 897 /* 898 * Show that the object has one more resident page. 899 */ 900 object->resident_page_count++; 901 902 /* 903 * Hold the vnode until the last page is released. 904 */ 905 if (object->resident_page_count == 1 && object->type == OBJT_VNODE) 906 vhold(object->handle); 907 908 /* 909 * Since we are inserting a new and possibly dirty page, 910 * update the object's OBJ_MIGHTBEDIRTY flag. 911 */ 912 if (pmap_page_is_write_mapped(m)) 913 vm_object_set_writeable_dirty(object); 914 } 915 916 /* 917 * vm_page_remove: 918 * 919 * Removes the given mem entry from the object/offset-page 920 * table and the object page list, but do not invalidate/terminate 921 * the backing store. 922 * 923 * The underlying pmap entry (if any) is NOT removed here. 924 * 925 * The object must be locked. The page must be locked if it is managed. 926 */ 927 void 928 vm_page_remove(vm_page_t m) 929 { 930 vm_object_t object; 931 vm_page_t next, prev, root; 932 933 if ((m->oflags & VPO_UNMANAGED) == 0) 934 vm_page_lock_assert(m, MA_OWNED); 935 if ((object = m->object) == NULL) 936 return; 937 VM_OBJECT_LOCK_ASSERT(object, MA_OWNED); 938 if (m->oflags & VPO_BUSY) { 939 m->oflags &= ~VPO_BUSY; 940 vm_page_flash(m); 941 } 942 943 /* 944 * Now remove from the object's list of backed pages. 945 */ 946 if ((next = TAILQ_NEXT(m, listq)) != NULL && next->left == m) { 947 /* 948 * Since the page's successor in the list is also its parent 949 * in the tree, its right subtree must be empty. 950 */ 951 next->left = m->left; 952 KASSERT(m->right == NULL, 953 ("vm_page_remove: page %p has right child", m)); 954 } else if ((prev = TAILQ_PREV(m, pglist, listq)) != NULL && 955 prev->right == m) { 956 /* 957 * Since the page's predecessor in the list is also its parent 958 * in the tree, its left subtree must be empty. 959 */ 960 KASSERT(m->left == NULL, 961 ("vm_page_remove: page %p has left child", m)); 962 prev->right = m->right; 963 } else { 964 if (m != object->root) 965 vm_page_splay(m->pindex, object->root); 966 if (m->left == NULL) 967 root = m->right; 968 else if (m->right == NULL) 969 root = m->left; 970 else { 971 /* 972 * Move the page's successor to the root, because 973 * pages are usually removed in ascending order. 974 */ 975 if (m->right != next) 976 vm_page_splay(m->pindex, m->right); 977 next->left = m->left; 978 root = next; 979 } 980 object->root = root; 981 } 982 TAILQ_REMOVE(&object->memq, m, listq); 983 984 /* 985 * And show that the object has one fewer resident page. 986 */ 987 object->resident_page_count--; 988 989 /* 990 * The vnode may now be recycled. 991 */ 992 if (object->resident_page_count == 0 && object->type == OBJT_VNODE) 993 vdrop(object->handle); 994 995 m->object = NULL; 996 } 997 998 /* 999 * vm_page_lookup: 1000 * 1001 * Returns the page associated with the object/offset 1002 * pair specified; if none is found, NULL is returned. 1003 * 1004 * The object must be locked. 1005 */ 1006 vm_page_t 1007 vm_page_lookup(vm_object_t object, vm_pindex_t pindex) 1008 { 1009 vm_page_t m; 1010 1011 VM_OBJECT_LOCK_ASSERT(object, MA_OWNED); 1012 if ((m = object->root) != NULL && m->pindex != pindex) { 1013 m = vm_page_splay(pindex, m); 1014 if ((object->root = m)->pindex != pindex) 1015 m = NULL; 1016 } 1017 return (m); 1018 } 1019 1020 /* 1021 * vm_page_find_least: 1022 * 1023 * Returns the page associated with the object with least pindex 1024 * greater than or equal to the parameter pindex, or NULL. 1025 * 1026 * The object must be locked. 1027 */ 1028 vm_page_t 1029 vm_page_find_least(vm_object_t object, vm_pindex_t pindex) 1030 { 1031 vm_page_t m; 1032 1033 VM_OBJECT_LOCK_ASSERT(object, MA_OWNED); 1034 if ((m = TAILQ_FIRST(&object->memq)) != NULL) { 1035 if (m->pindex < pindex) { 1036 m = vm_page_splay(pindex, object->root); 1037 if ((object->root = m)->pindex < pindex) 1038 m = TAILQ_NEXT(m, listq); 1039 } 1040 } 1041 return (m); 1042 } 1043 1044 /* 1045 * Returns the given page's successor (by pindex) within the object if it is 1046 * resident; if none is found, NULL is returned. 1047 * 1048 * The object must be locked. 1049 */ 1050 vm_page_t 1051 vm_page_next(vm_page_t m) 1052 { 1053 vm_page_t next; 1054 1055 VM_OBJECT_LOCK_ASSERT(m->object, MA_OWNED); 1056 if ((next = TAILQ_NEXT(m, listq)) != NULL && 1057 next->pindex != m->pindex + 1) 1058 next = NULL; 1059 return (next); 1060 } 1061 1062 /* 1063 * Returns the given page's predecessor (by pindex) within the object if it is 1064 * resident; if none is found, NULL is returned. 1065 * 1066 * The object must be locked. 1067 */ 1068 vm_page_t 1069 vm_page_prev(vm_page_t m) 1070 { 1071 vm_page_t prev; 1072 1073 VM_OBJECT_LOCK_ASSERT(m->object, MA_OWNED); 1074 if ((prev = TAILQ_PREV(m, pglist, listq)) != NULL && 1075 prev->pindex != m->pindex - 1) 1076 prev = NULL; 1077 return (prev); 1078 } 1079 1080 /* 1081 * vm_page_rename: 1082 * 1083 * Move the given memory entry from its 1084 * current object to the specified target object/offset. 1085 * 1086 * Note: swap associated with the page must be invalidated by the move. We 1087 * have to do this for several reasons: (1) we aren't freeing the 1088 * page, (2) we are dirtying the page, (3) the VM system is probably 1089 * moving the page from object A to B, and will then later move 1090 * the backing store from A to B and we can't have a conflict. 1091 * 1092 * Note: we *always* dirty the page. It is necessary both for the 1093 * fact that we moved it, and because we may be invalidating 1094 * swap. If the page is on the cache, we have to deactivate it 1095 * or vm_page_dirty() will panic. Dirty pages are not allowed 1096 * on the cache. 1097 * 1098 * The objects must be locked. The page must be locked if it is managed. 1099 */ 1100 void 1101 vm_page_rename(vm_page_t m, vm_object_t new_object, vm_pindex_t new_pindex) 1102 { 1103 1104 vm_page_remove(m); 1105 vm_page_insert(m, new_object, new_pindex); 1106 vm_page_dirty(m); 1107 } 1108 1109 /* 1110 * Convert all of the given object's cached pages that have a 1111 * pindex within the given range into free pages. If the value 1112 * zero is given for "end", then the range's upper bound is 1113 * infinity. If the given object is backed by a vnode and it 1114 * transitions from having one or more cached pages to none, the 1115 * vnode's hold count is reduced. 1116 */ 1117 void 1118 vm_page_cache_free(vm_object_t object, vm_pindex_t start, vm_pindex_t end) 1119 { 1120 vm_page_t m, m_next; 1121 boolean_t empty; 1122 1123 mtx_lock(&vm_page_queue_free_mtx); 1124 if (__predict_false(object->cache == NULL)) { 1125 mtx_unlock(&vm_page_queue_free_mtx); 1126 return; 1127 } 1128 m = object->cache = vm_page_splay(start, object->cache); 1129 if (m->pindex < start) { 1130 if (m->right == NULL) 1131 m = NULL; 1132 else { 1133 m_next = vm_page_splay(start, m->right); 1134 m_next->left = m; 1135 m->right = NULL; 1136 m = object->cache = m_next; 1137 } 1138 } 1139 1140 /* 1141 * At this point, "m" is either (1) a reference to the page 1142 * with the least pindex that is greater than or equal to 1143 * "start" or (2) NULL. 1144 */ 1145 for (; m != NULL && (m->pindex < end || end == 0); m = m_next) { 1146 /* 1147 * Find "m"'s successor and remove "m" from the 1148 * object's cache. 1149 */ 1150 if (m->right == NULL) { 1151 object->cache = m->left; 1152 m_next = NULL; 1153 } else { 1154 m_next = vm_page_splay(start, m->right); 1155 m_next->left = m->left; 1156 object->cache = m_next; 1157 } 1158 /* Convert "m" to a free page. */ 1159 m->object = NULL; 1160 m->valid = 0; 1161 /* Clear PG_CACHED and set PG_FREE. */ 1162 m->flags ^= PG_CACHED | PG_FREE; 1163 KASSERT((m->flags & (PG_CACHED | PG_FREE)) == PG_FREE, 1164 ("vm_page_cache_free: page %p has inconsistent flags", m)); 1165 cnt.v_cache_count--; 1166 cnt.v_free_count++; 1167 } 1168 empty = object->cache == NULL; 1169 mtx_unlock(&vm_page_queue_free_mtx); 1170 if (object->type == OBJT_VNODE && empty) 1171 vdrop(object->handle); 1172 } 1173 1174 /* 1175 * Returns the cached page that is associated with the given 1176 * object and offset. If, however, none exists, returns NULL. 1177 * 1178 * The free page queue must be locked. 1179 */ 1180 static inline vm_page_t 1181 vm_page_cache_lookup(vm_object_t object, vm_pindex_t pindex) 1182 { 1183 vm_page_t m; 1184 1185 mtx_assert(&vm_page_queue_free_mtx, MA_OWNED); 1186 if ((m = object->cache) != NULL && m->pindex != pindex) { 1187 m = vm_page_splay(pindex, m); 1188 if ((object->cache = m)->pindex != pindex) 1189 m = NULL; 1190 } 1191 return (m); 1192 } 1193 1194 /* 1195 * Remove the given cached page from its containing object's 1196 * collection of cached pages. 1197 * 1198 * The free page queue must be locked. 1199 */ 1200 static void 1201 vm_page_cache_remove(vm_page_t m) 1202 { 1203 vm_object_t object; 1204 vm_page_t root; 1205 1206 mtx_assert(&vm_page_queue_free_mtx, MA_OWNED); 1207 KASSERT((m->flags & PG_CACHED) != 0, 1208 ("vm_page_cache_remove: page %p is not cached", m)); 1209 object = m->object; 1210 if (m != object->cache) { 1211 root = vm_page_splay(m->pindex, object->cache); 1212 KASSERT(root == m, 1213 ("vm_page_cache_remove: page %p is not cached in object %p", 1214 m, object)); 1215 } 1216 if (m->left == NULL) 1217 root = m->right; 1218 else if (m->right == NULL) 1219 root = m->left; 1220 else { 1221 root = vm_page_splay(m->pindex, m->left); 1222 root->right = m->right; 1223 } 1224 object->cache = root; 1225 m->object = NULL; 1226 cnt.v_cache_count--; 1227 } 1228 1229 /* 1230 * Transfer all of the cached pages with offset greater than or 1231 * equal to 'offidxstart' from the original object's cache to the 1232 * new object's cache. However, any cached pages with offset 1233 * greater than or equal to the new object's size are kept in the 1234 * original object. Initially, the new object's cache must be 1235 * empty. Offset 'offidxstart' in the original object must 1236 * correspond to offset zero in the new object. 1237 * 1238 * The new object must be locked. 1239 */ 1240 void 1241 vm_page_cache_transfer(vm_object_t orig_object, vm_pindex_t offidxstart, 1242 vm_object_t new_object) 1243 { 1244 vm_page_t m, m_next; 1245 1246 /* 1247 * Insertion into an object's collection of cached pages 1248 * requires the object to be locked. In contrast, removal does 1249 * not. 1250 */ 1251 VM_OBJECT_LOCK_ASSERT(new_object, MA_OWNED); 1252 KASSERT(new_object->cache == NULL, 1253 ("vm_page_cache_transfer: object %p has cached pages", 1254 new_object)); 1255 mtx_lock(&vm_page_queue_free_mtx); 1256 if ((m = orig_object->cache) != NULL) { 1257 /* 1258 * Transfer all of the pages with offset greater than or 1259 * equal to 'offidxstart' from the original object's 1260 * cache to the new object's cache. 1261 */ 1262 m = vm_page_splay(offidxstart, m); 1263 if (m->pindex < offidxstart) { 1264 orig_object->cache = m; 1265 new_object->cache = m->right; 1266 m->right = NULL; 1267 } else { 1268 orig_object->cache = m->left; 1269 new_object->cache = m; 1270 m->left = NULL; 1271 } 1272 while ((m = new_object->cache) != NULL) { 1273 if ((m->pindex - offidxstart) >= new_object->size) { 1274 /* 1275 * Return all of the cached pages with 1276 * offset greater than or equal to the 1277 * new object's size to the original 1278 * object's cache. 1279 */ 1280 new_object->cache = m->left; 1281 m->left = orig_object->cache; 1282 orig_object->cache = m; 1283 break; 1284 } 1285 m_next = vm_page_splay(m->pindex, m->right); 1286 /* Update the page's object and offset. */ 1287 m->object = new_object; 1288 m->pindex -= offidxstart; 1289 if (m_next == NULL) 1290 break; 1291 m->right = NULL; 1292 m_next->left = m; 1293 new_object->cache = m_next; 1294 } 1295 KASSERT(new_object->cache == NULL || 1296 new_object->type == OBJT_SWAP, 1297 ("vm_page_cache_transfer: object %p's type is incompatible" 1298 " with cached pages", new_object)); 1299 } 1300 mtx_unlock(&vm_page_queue_free_mtx); 1301 } 1302 1303 /* 1304 * Returns TRUE if a cached page is associated with the given object and 1305 * offset, and FALSE otherwise. 1306 * 1307 * The object must be locked. 1308 */ 1309 boolean_t 1310 vm_page_is_cached(vm_object_t object, vm_pindex_t pindex) 1311 { 1312 vm_page_t m; 1313 1314 /* 1315 * Insertion into an object's collection of cached pages requires the 1316 * object to be locked. Therefore, if the object is locked and the 1317 * object's collection is empty, there is no need to acquire the free 1318 * page queues lock in order to prove that the specified page doesn't 1319 * exist. 1320 */ 1321 VM_OBJECT_LOCK_ASSERT(object, MA_OWNED); 1322 if (__predict_true(object->cache == NULL)) 1323 return (FALSE); 1324 mtx_lock(&vm_page_queue_free_mtx); 1325 m = vm_page_cache_lookup(object, pindex); 1326 mtx_unlock(&vm_page_queue_free_mtx); 1327 return (m != NULL); 1328 } 1329 1330 /* 1331 * vm_page_alloc: 1332 * 1333 * Allocate and return a page that is associated with the specified 1334 * object and offset pair. By default, this page has the flag VPO_BUSY 1335 * set. 1336 * 1337 * The caller must always specify an allocation class. 1338 * 1339 * allocation classes: 1340 * VM_ALLOC_NORMAL normal process request 1341 * VM_ALLOC_SYSTEM system *really* needs a page 1342 * VM_ALLOC_INTERRUPT interrupt time request 1343 * 1344 * optional allocation flags: 1345 * VM_ALLOC_COUNT(number) the number of additional pages that the caller 1346 * intends to allocate 1347 * VM_ALLOC_IFCACHED return page only if it is cached 1348 * VM_ALLOC_IFNOTCACHED return NULL, do not reactivate if the page 1349 * is cached 1350 * VM_ALLOC_NOBUSY do not set the flag VPO_BUSY on the page 1351 * VM_ALLOC_NODUMP do not include the page in a kernel core dump 1352 * VM_ALLOC_NOOBJ page is not associated with an object and 1353 * should not have the flag VPO_BUSY set 1354 * VM_ALLOC_WIRED wire the allocated page 1355 * VM_ALLOC_ZERO prefer a zeroed page 1356 * 1357 * This routine may not sleep. 1358 */ 1359 vm_page_t 1360 vm_page_alloc(vm_object_t object, vm_pindex_t pindex, int req) 1361 { 1362 struct vnode *vp = NULL; 1363 vm_object_t m_object; 1364 vm_page_t m; 1365 int flags, req_class; 1366 1367 KASSERT((object != NULL) == ((req & VM_ALLOC_NOOBJ) == 0), 1368 ("vm_page_alloc: inconsistent object/req")); 1369 if (object != NULL) 1370 VM_OBJECT_LOCK_ASSERT(object, MA_OWNED); 1371 1372 req_class = req & VM_ALLOC_CLASS_MASK; 1373 1374 /* 1375 * The page daemon is allowed to dig deeper into the free page list. 1376 */ 1377 if (curproc == pageproc && req_class != VM_ALLOC_INTERRUPT) 1378 req_class = VM_ALLOC_SYSTEM; 1379 1380 mtx_lock(&vm_page_queue_free_mtx); 1381 if (cnt.v_free_count + cnt.v_cache_count > cnt.v_free_reserved || 1382 (req_class == VM_ALLOC_SYSTEM && 1383 cnt.v_free_count + cnt.v_cache_count > cnt.v_interrupt_free_min) || 1384 (req_class == VM_ALLOC_INTERRUPT && 1385 cnt.v_free_count + cnt.v_cache_count > 0)) { 1386 /* 1387 * Allocate from the free queue if the number of free pages 1388 * exceeds the minimum for the request class. 1389 */ 1390 if (object != NULL && 1391 (m = vm_page_cache_lookup(object, pindex)) != NULL) { 1392 if ((req & VM_ALLOC_IFNOTCACHED) != 0) { 1393 mtx_unlock(&vm_page_queue_free_mtx); 1394 return (NULL); 1395 } 1396 if (vm_phys_unfree_page(m)) 1397 vm_phys_set_pool(VM_FREEPOOL_DEFAULT, m, 0); 1398 #if VM_NRESERVLEVEL > 0 1399 else if (!vm_reserv_reactivate_page(m)) 1400 #else 1401 else 1402 #endif 1403 panic("vm_page_alloc: cache page %p is missing" 1404 " from the free queue", m); 1405 } else if ((req & VM_ALLOC_IFCACHED) != 0) { 1406 mtx_unlock(&vm_page_queue_free_mtx); 1407 return (NULL); 1408 #if VM_NRESERVLEVEL > 0 1409 } else if (object == NULL || object->type == OBJT_DEVICE || 1410 object->type == OBJT_SG || 1411 (object->flags & OBJ_COLORED) == 0 || 1412 (m = vm_reserv_alloc_page(object, pindex)) == NULL) { 1413 #else 1414 } else { 1415 #endif 1416 m = vm_phys_alloc_pages(object != NULL ? 1417 VM_FREEPOOL_DEFAULT : VM_FREEPOOL_DIRECT, 0); 1418 #if VM_NRESERVLEVEL > 0 1419 if (m == NULL && vm_reserv_reclaim_inactive()) { 1420 m = vm_phys_alloc_pages(object != NULL ? 1421 VM_FREEPOOL_DEFAULT : VM_FREEPOOL_DIRECT, 1422 0); 1423 } 1424 #endif 1425 } 1426 } else { 1427 /* 1428 * Not allocatable, give up. 1429 */ 1430 mtx_unlock(&vm_page_queue_free_mtx); 1431 atomic_add_int(&vm_pageout_deficit, 1432 max((u_int)req >> VM_ALLOC_COUNT_SHIFT, 1)); 1433 pagedaemon_wakeup(); 1434 return (NULL); 1435 } 1436 1437 /* 1438 * At this point we had better have found a good page. 1439 */ 1440 KASSERT(m != NULL, ("vm_page_alloc: missing page")); 1441 KASSERT(m->queue == PQ_NONE, 1442 ("vm_page_alloc: page %p has unexpected queue %d", m, m->queue)); 1443 KASSERT(m->wire_count == 0, ("vm_page_alloc: page %p is wired", m)); 1444 KASSERT(m->hold_count == 0, ("vm_page_alloc: page %p is held", m)); 1445 KASSERT(m->busy == 0, ("vm_page_alloc: page %p is busy", m)); 1446 KASSERT(m->dirty == 0, ("vm_page_alloc: page %p is dirty", m)); 1447 KASSERT(pmap_page_get_memattr(m) == VM_MEMATTR_DEFAULT, 1448 ("vm_page_alloc: page %p has unexpected memattr %d", m, 1449 pmap_page_get_memattr(m))); 1450 if ((m->flags & PG_CACHED) != 0) { 1451 KASSERT((m->flags & PG_ZERO) == 0, 1452 ("vm_page_alloc: cached page %p is PG_ZERO", m)); 1453 KASSERT(m->valid != 0, 1454 ("vm_page_alloc: cached page %p is invalid", m)); 1455 if (m->object == object && m->pindex == pindex) 1456 cnt.v_reactivated++; 1457 else 1458 m->valid = 0; 1459 m_object = m->object; 1460 vm_page_cache_remove(m); 1461 if (m_object->type == OBJT_VNODE && m_object->cache == NULL) 1462 vp = m_object->handle; 1463 } else { 1464 KASSERT(VM_PAGE_IS_FREE(m), 1465 ("vm_page_alloc: page %p is not free", m)); 1466 KASSERT(m->valid == 0, 1467 ("vm_page_alloc: free page %p is valid", m)); 1468 cnt.v_free_count--; 1469 } 1470 1471 /* 1472 * Only the PG_ZERO flag is inherited. The PG_CACHED or PG_FREE flag 1473 * must be cleared before the free page queues lock is released. 1474 */ 1475 flags = 0; 1476 if (req & VM_ALLOC_NODUMP) 1477 flags |= PG_NODUMP; 1478 if (m->flags & PG_ZERO) { 1479 vm_page_zero_count--; 1480 if (req & VM_ALLOC_ZERO) 1481 flags = PG_ZERO; 1482 } 1483 m->flags = flags; 1484 mtx_unlock(&vm_page_queue_free_mtx); 1485 m->aflags = 0; 1486 if (object == NULL || object->type == OBJT_PHYS) 1487 m->oflags = VPO_UNMANAGED; 1488 else 1489 m->oflags = 0; 1490 if ((req & (VM_ALLOC_NOBUSY | VM_ALLOC_NOOBJ)) == 0) 1491 m->oflags |= VPO_BUSY; 1492 if (req & VM_ALLOC_WIRED) { 1493 /* 1494 * The page lock is not required for wiring a page until that 1495 * page is inserted into the object. 1496 */ 1497 atomic_add_int(&cnt.v_wire_count, 1); 1498 m->wire_count = 1; 1499 } 1500 m->act_count = 0; 1501 1502 if (object != NULL) { 1503 /* Ignore device objects; the pager sets "memattr" for them. */ 1504 if (object->memattr != VM_MEMATTR_DEFAULT && 1505 object->type != OBJT_DEVICE && object->type != OBJT_SG) 1506 pmap_page_set_memattr(m, object->memattr); 1507 vm_page_insert(m, object, pindex); 1508 } else 1509 m->pindex = pindex; 1510 1511 /* 1512 * The following call to vdrop() must come after the above call 1513 * to vm_page_insert() in case both affect the same object and 1514 * vnode. Otherwise, the affected vnode's hold count could 1515 * temporarily become zero. 1516 */ 1517 if (vp != NULL) 1518 vdrop(vp); 1519 1520 /* 1521 * Don't wakeup too often - wakeup the pageout daemon when 1522 * we would be nearly out of memory. 1523 */ 1524 if (vm_paging_needed()) 1525 pagedaemon_wakeup(); 1526 1527 return (m); 1528 } 1529 1530 /* 1531 * vm_page_alloc_contig: 1532 * 1533 * Allocate a contiguous set of physical pages of the given size "npages" 1534 * from the free lists. All of the physical pages must be at or above 1535 * the given physical address "low" and below the given physical address 1536 * "high". The given value "alignment" determines the alignment of the 1537 * first physical page in the set. If the given value "boundary" is 1538 * non-zero, then the set of physical pages cannot cross any physical 1539 * address boundary that is a multiple of that value. Both "alignment" 1540 * and "boundary" must be a power of two. 1541 * 1542 * If the specified memory attribute, "memattr", is VM_MEMATTR_DEFAULT, 1543 * then the memory attribute setting for the physical pages is configured 1544 * to the object's memory attribute setting. Otherwise, the memory 1545 * attribute setting for the physical pages is configured to "memattr", 1546 * overriding the object's memory attribute setting. However, if the 1547 * object's memory attribute setting is not VM_MEMATTR_DEFAULT, then the 1548 * memory attribute setting for the physical pages cannot be configured 1549 * to VM_MEMATTR_DEFAULT. 1550 * 1551 * The caller must always specify an allocation class. 1552 * 1553 * allocation classes: 1554 * VM_ALLOC_NORMAL normal process request 1555 * VM_ALLOC_SYSTEM system *really* needs a page 1556 * VM_ALLOC_INTERRUPT interrupt time request 1557 * 1558 * optional allocation flags: 1559 * VM_ALLOC_NOBUSY do not set the flag VPO_BUSY on the page 1560 * VM_ALLOC_NOOBJ page is not associated with an object and 1561 * should not have the flag VPO_BUSY set 1562 * VM_ALLOC_WIRED wire the allocated page 1563 * VM_ALLOC_ZERO prefer a zeroed page 1564 * 1565 * This routine may not sleep. 1566 */ 1567 vm_page_t 1568 vm_page_alloc_contig(vm_object_t object, vm_pindex_t pindex, int req, 1569 u_long npages, vm_paddr_t low, vm_paddr_t high, u_long alignment, 1570 vm_paddr_t boundary, vm_memattr_t memattr) 1571 { 1572 struct vnode *drop; 1573 vm_page_t deferred_vdrop_list, m, m_ret; 1574 u_int flags, oflags; 1575 int req_class; 1576 1577 KASSERT((object != NULL) == ((req & VM_ALLOC_NOOBJ) == 0), 1578 ("vm_page_alloc_contig: inconsistent object/req")); 1579 if (object != NULL) { 1580 VM_OBJECT_LOCK_ASSERT(object, MA_OWNED); 1581 KASSERT(object->type == OBJT_PHYS, 1582 ("vm_page_alloc_contig: object %p isn't OBJT_PHYS", 1583 object)); 1584 } 1585 KASSERT(npages > 0, ("vm_page_alloc_contig: npages is zero")); 1586 req_class = req & VM_ALLOC_CLASS_MASK; 1587 1588 /* 1589 * The page daemon is allowed to dig deeper into the free page list. 1590 */ 1591 if (curproc == pageproc && req_class != VM_ALLOC_INTERRUPT) 1592 req_class = VM_ALLOC_SYSTEM; 1593 1594 deferred_vdrop_list = NULL; 1595 mtx_lock(&vm_page_queue_free_mtx); 1596 if (cnt.v_free_count + cnt.v_cache_count >= npages + 1597 cnt.v_free_reserved || (req_class == VM_ALLOC_SYSTEM && 1598 cnt.v_free_count + cnt.v_cache_count >= npages + 1599 cnt.v_interrupt_free_min) || (req_class == VM_ALLOC_INTERRUPT && 1600 cnt.v_free_count + cnt.v_cache_count >= npages)) { 1601 #if VM_NRESERVLEVEL > 0 1602 retry: 1603 if (object == NULL || (object->flags & OBJ_COLORED) == 0 || 1604 (m_ret = vm_reserv_alloc_contig(object, pindex, npages, 1605 low, high, alignment, boundary)) == NULL) 1606 #endif 1607 m_ret = vm_phys_alloc_contig(npages, low, high, 1608 alignment, boundary); 1609 } else { 1610 mtx_unlock(&vm_page_queue_free_mtx); 1611 atomic_add_int(&vm_pageout_deficit, npages); 1612 pagedaemon_wakeup(); 1613 return (NULL); 1614 } 1615 if (m_ret != NULL) 1616 for (m = m_ret; m < &m_ret[npages]; m++) { 1617 drop = vm_page_alloc_init(m); 1618 if (drop != NULL) { 1619 /* 1620 * Enqueue the vnode for deferred vdrop(). 1621 * 1622 * Once the pages are removed from the free 1623 * page list, "pageq" can be safely abused to 1624 * construct a short-lived list of vnodes. 1625 */ 1626 m->pageq.tqe_prev = (void *)drop; 1627 m->pageq.tqe_next = deferred_vdrop_list; 1628 deferred_vdrop_list = m; 1629 } 1630 } 1631 else { 1632 #if VM_NRESERVLEVEL > 0 1633 if (vm_reserv_reclaim_contig(npages, low, high, alignment, 1634 boundary)) 1635 goto retry; 1636 #endif 1637 } 1638 mtx_unlock(&vm_page_queue_free_mtx); 1639 if (m_ret == NULL) 1640 return (NULL); 1641 1642 /* 1643 * Initialize the pages. Only the PG_ZERO flag is inherited. 1644 */ 1645 flags = 0; 1646 if ((req & VM_ALLOC_ZERO) != 0) 1647 flags = PG_ZERO; 1648 if ((req & VM_ALLOC_NODUMP) != 0) 1649 flags |= PG_NODUMP; 1650 if ((req & VM_ALLOC_WIRED) != 0) 1651 atomic_add_int(&cnt.v_wire_count, npages); 1652 oflags = VPO_UNMANAGED; 1653 if (object != NULL) { 1654 if ((req & VM_ALLOC_NOBUSY) == 0) 1655 oflags |= VPO_BUSY; 1656 if (object->memattr != VM_MEMATTR_DEFAULT && 1657 memattr == VM_MEMATTR_DEFAULT) 1658 memattr = object->memattr; 1659 } 1660 for (m = m_ret; m < &m_ret[npages]; m++) { 1661 m->aflags = 0; 1662 m->flags = (m->flags | PG_NODUMP) & flags; 1663 if ((req & VM_ALLOC_WIRED) != 0) 1664 m->wire_count = 1; 1665 /* Unmanaged pages don't use "act_count". */ 1666 m->oflags = oflags; 1667 if (memattr != VM_MEMATTR_DEFAULT) 1668 pmap_page_set_memattr(m, memattr); 1669 if (object != NULL) 1670 vm_page_insert(m, object, pindex); 1671 else 1672 m->pindex = pindex; 1673 pindex++; 1674 } 1675 while (deferred_vdrop_list != NULL) { 1676 vdrop((struct vnode *)deferred_vdrop_list->pageq.tqe_prev); 1677 deferred_vdrop_list = deferred_vdrop_list->pageq.tqe_next; 1678 } 1679 if (vm_paging_needed()) 1680 pagedaemon_wakeup(); 1681 return (m_ret); 1682 } 1683 1684 /* 1685 * Initialize a page that has been freshly dequeued from a freelist. 1686 * The caller has to drop the vnode returned, if it is not NULL. 1687 * 1688 * This function may only be used to initialize unmanaged pages. 1689 * 1690 * To be called with vm_page_queue_free_mtx held. 1691 */ 1692 static struct vnode * 1693 vm_page_alloc_init(vm_page_t m) 1694 { 1695 struct vnode *drop; 1696 vm_object_t m_object; 1697 1698 KASSERT(m->queue == PQ_NONE, 1699 ("vm_page_alloc_init: page %p has unexpected queue %d", 1700 m, m->queue)); 1701 KASSERT(m->wire_count == 0, 1702 ("vm_page_alloc_init: page %p is wired", m)); 1703 KASSERT(m->hold_count == 0, 1704 ("vm_page_alloc_init: page %p is held", m)); 1705 KASSERT(m->busy == 0, 1706 ("vm_page_alloc_init: page %p is busy", m)); 1707 KASSERT(m->dirty == 0, 1708 ("vm_page_alloc_init: page %p is dirty", m)); 1709 KASSERT(pmap_page_get_memattr(m) == VM_MEMATTR_DEFAULT, 1710 ("vm_page_alloc_init: page %p has unexpected memattr %d", 1711 m, pmap_page_get_memattr(m))); 1712 mtx_assert(&vm_page_queue_free_mtx, MA_OWNED); 1713 drop = NULL; 1714 if ((m->flags & PG_CACHED) != 0) { 1715 KASSERT((m->flags & PG_ZERO) == 0, 1716 ("vm_page_alloc_init: cached page %p is PG_ZERO", m)); 1717 m->valid = 0; 1718 m_object = m->object; 1719 vm_page_cache_remove(m); 1720 if (m_object->type == OBJT_VNODE && m_object->cache == NULL) 1721 drop = m_object->handle; 1722 } else { 1723 KASSERT(VM_PAGE_IS_FREE(m), 1724 ("vm_page_alloc_init: page %p is not free", m)); 1725 KASSERT(m->valid == 0, 1726 ("vm_page_alloc_init: free page %p is valid", m)); 1727 cnt.v_free_count--; 1728 if ((m->flags & PG_ZERO) != 0) 1729 vm_page_zero_count--; 1730 } 1731 /* Don't clear the PG_ZERO flag; we'll need it later. */ 1732 m->flags &= PG_ZERO; 1733 return (drop); 1734 } 1735 1736 /* 1737 * vm_page_alloc_freelist: 1738 * 1739 * Allocate a physical page from the specified free page list. 1740 * 1741 * The caller must always specify an allocation class. 1742 * 1743 * allocation classes: 1744 * VM_ALLOC_NORMAL normal process request 1745 * VM_ALLOC_SYSTEM system *really* needs a page 1746 * VM_ALLOC_INTERRUPT interrupt time request 1747 * 1748 * optional allocation flags: 1749 * VM_ALLOC_COUNT(number) the number of additional pages that the caller 1750 * intends to allocate 1751 * VM_ALLOC_WIRED wire the allocated page 1752 * VM_ALLOC_ZERO prefer a zeroed page 1753 * 1754 * This routine may not sleep. 1755 */ 1756 vm_page_t 1757 vm_page_alloc_freelist(int flind, int req) 1758 { 1759 struct vnode *drop; 1760 vm_page_t m; 1761 u_int flags; 1762 int req_class; 1763 1764 req_class = req & VM_ALLOC_CLASS_MASK; 1765 1766 /* 1767 * The page daemon is allowed to dig deeper into the free page list. 1768 */ 1769 if (curproc == pageproc && req_class != VM_ALLOC_INTERRUPT) 1770 req_class = VM_ALLOC_SYSTEM; 1771 1772 /* 1773 * Do not allocate reserved pages unless the req has asked for it. 1774 */ 1775 mtx_lock(&vm_page_queue_free_mtx); 1776 if (cnt.v_free_count + cnt.v_cache_count > cnt.v_free_reserved || 1777 (req_class == VM_ALLOC_SYSTEM && 1778 cnt.v_free_count + cnt.v_cache_count > cnt.v_interrupt_free_min) || 1779 (req_class == VM_ALLOC_INTERRUPT && 1780 cnt.v_free_count + cnt.v_cache_count > 0)) 1781 m = vm_phys_alloc_freelist_pages(flind, VM_FREEPOOL_DIRECT, 0); 1782 else { 1783 mtx_unlock(&vm_page_queue_free_mtx); 1784 atomic_add_int(&vm_pageout_deficit, 1785 max((u_int)req >> VM_ALLOC_COUNT_SHIFT, 1)); 1786 pagedaemon_wakeup(); 1787 return (NULL); 1788 } 1789 if (m == NULL) { 1790 mtx_unlock(&vm_page_queue_free_mtx); 1791 return (NULL); 1792 } 1793 drop = vm_page_alloc_init(m); 1794 mtx_unlock(&vm_page_queue_free_mtx); 1795 1796 /* 1797 * Initialize the page. Only the PG_ZERO flag is inherited. 1798 */ 1799 m->aflags = 0; 1800 flags = 0; 1801 if ((req & VM_ALLOC_ZERO) != 0) 1802 flags = PG_ZERO; 1803 m->flags &= flags; 1804 if ((req & VM_ALLOC_WIRED) != 0) { 1805 /* 1806 * The page lock is not required for wiring a page that does 1807 * not belong to an object. 1808 */ 1809 atomic_add_int(&cnt.v_wire_count, 1); 1810 m->wire_count = 1; 1811 } 1812 /* Unmanaged pages don't use "act_count". */ 1813 m->oflags = VPO_UNMANAGED; 1814 if (drop != NULL) 1815 vdrop(drop); 1816 if (vm_paging_needed()) 1817 pagedaemon_wakeup(); 1818 return (m); 1819 } 1820 1821 /* 1822 * vm_wait: (also see VM_WAIT macro) 1823 * 1824 * Sleep until free pages are available for allocation. 1825 * - Called in various places before memory allocations. 1826 */ 1827 void 1828 vm_wait(void) 1829 { 1830 1831 mtx_lock(&vm_page_queue_free_mtx); 1832 if (curproc == pageproc) { 1833 vm_pageout_pages_needed = 1; 1834 msleep(&vm_pageout_pages_needed, &vm_page_queue_free_mtx, 1835 PDROP | PSWP, "VMWait", 0); 1836 } else { 1837 if (!vm_pages_needed) { 1838 vm_pages_needed = 1; 1839 wakeup(&vm_pages_needed); 1840 } 1841 msleep(&cnt.v_free_count, &vm_page_queue_free_mtx, PDROP | PVM, 1842 "vmwait", 0); 1843 } 1844 } 1845 1846 /* 1847 * vm_waitpfault: (also see VM_WAITPFAULT macro) 1848 * 1849 * Sleep until free pages are available for allocation. 1850 * - Called only in vm_fault so that processes page faulting 1851 * can be easily tracked. 1852 * - Sleeps at a lower priority than vm_wait() so that vm_wait()ing 1853 * processes will be able to grab memory first. Do not change 1854 * this balance without careful testing first. 1855 */ 1856 void 1857 vm_waitpfault(void) 1858 { 1859 1860 mtx_lock(&vm_page_queue_free_mtx); 1861 if (!vm_pages_needed) { 1862 vm_pages_needed = 1; 1863 wakeup(&vm_pages_needed); 1864 } 1865 msleep(&cnt.v_free_count, &vm_page_queue_free_mtx, PDROP | PUSER, 1866 "pfault", 0); 1867 } 1868 1869 /* 1870 * vm_page_queue_remove: 1871 * 1872 * Remove the given page from the specified queue. 1873 * 1874 * The page and page queues must be locked. 1875 */ 1876 static __inline void 1877 vm_page_queue_remove(int queue, vm_page_t m) 1878 { 1879 struct vpgqueues *pq; 1880 1881 mtx_assert(&vm_page_queue_mtx, MA_OWNED); 1882 vm_page_lock_assert(m, MA_OWNED); 1883 pq = &vm_page_queues[queue]; 1884 TAILQ_REMOVE(&pq->pl, m, pageq); 1885 (*pq->cnt)--; 1886 } 1887 1888 /* 1889 * vm_pageq_remove: 1890 * 1891 * Remove a page from its queue. 1892 * 1893 * The given page must be locked. 1894 */ 1895 void 1896 vm_pageq_remove(vm_page_t m) 1897 { 1898 int queue; 1899 1900 vm_page_lock_assert(m, MA_OWNED); 1901 if ((queue = m->queue) != PQ_NONE) { 1902 vm_page_lock_queues(); 1903 m->queue = PQ_NONE; 1904 vm_page_queue_remove(queue, m); 1905 vm_page_unlock_queues(); 1906 } 1907 } 1908 1909 /* 1910 * vm_page_enqueue: 1911 * 1912 * Add the given page to the specified queue. 1913 * 1914 * The page queues must be locked. 1915 */ 1916 static void 1917 vm_page_enqueue(int queue, vm_page_t m) 1918 { 1919 struct vpgqueues *vpq; 1920 1921 vpq = &vm_page_queues[queue]; 1922 m->queue = queue; 1923 TAILQ_INSERT_TAIL(&vpq->pl, m, pageq); 1924 ++*vpq->cnt; 1925 } 1926 1927 /* 1928 * vm_page_activate: 1929 * 1930 * Put the specified page on the active list (if appropriate). 1931 * Ensure that act_count is at least ACT_INIT but do not otherwise 1932 * mess with it. 1933 * 1934 * The page must be locked. 1935 */ 1936 void 1937 vm_page_activate(vm_page_t m) 1938 { 1939 int queue; 1940 1941 vm_page_lock_assert(m, MA_OWNED); 1942 VM_OBJECT_LOCK_ASSERT(m->object, MA_OWNED); 1943 if ((queue = m->queue) != PQ_ACTIVE) { 1944 if (m->wire_count == 0 && (m->oflags & VPO_UNMANAGED) == 0) { 1945 if (m->act_count < ACT_INIT) 1946 m->act_count = ACT_INIT; 1947 vm_page_lock_queues(); 1948 if (queue != PQ_NONE) 1949 vm_page_queue_remove(queue, m); 1950 vm_page_enqueue(PQ_ACTIVE, m); 1951 vm_page_unlock_queues(); 1952 } else 1953 KASSERT(queue == PQ_NONE, 1954 ("vm_page_activate: wired page %p is queued", m)); 1955 } else { 1956 if (m->act_count < ACT_INIT) 1957 m->act_count = ACT_INIT; 1958 } 1959 } 1960 1961 /* 1962 * vm_page_free_wakeup: 1963 * 1964 * Helper routine for vm_page_free_toq() and vm_page_cache(). This 1965 * routine is called when a page has been added to the cache or free 1966 * queues. 1967 * 1968 * The page queues must be locked. 1969 */ 1970 static inline void 1971 vm_page_free_wakeup(void) 1972 { 1973 1974 mtx_assert(&vm_page_queue_free_mtx, MA_OWNED); 1975 /* 1976 * if pageout daemon needs pages, then tell it that there are 1977 * some free. 1978 */ 1979 if (vm_pageout_pages_needed && 1980 cnt.v_cache_count + cnt.v_free_count >= cnt.v_pageout_free_min) { 1981 wakeup(&vm_pageout_pages_needed); 1982 vm_pageout_pages_needed = 0; 1983 } 1984 /* 1985 * wakeup processes that are waiting on memory if we hit a 1986 * high water mark. And wakeup scheduler process if we have 1987 * lots of memory. this process will swapin processes. 1988 */ 1989 if (vm_pages_needed && !vm_page_count_min()) { 1990 vm_pages_needed = 0; 1991 wakeup(&cnt.v_free_count); 1992 } 1993 } 1994 1995 /* 1996 * vm_page_free_toq: 1997 * 1998 * Returns the given page to the free list, 1999 * disassociating it with any VM object. 2000 * 2001 * The object must be locked. The page must be locked if it is managed. 2002 */ 2003 void 2004 vm_page_free_toq(vm_page_t m) 2005 { 2006 2007 if ((m->oflags & VPO_UNMANAGED) == 0) { 2008 vm_page_lock_assert(m, MA_OWNED); 2009 KASSERT(!pmap_page_is_mapped(m), 2010 ("vm_page_free_toq: freeing mapped page %p", m)); 2011 } 2012 PCPU_INC(cnt.v_tfree); 2013 2014 if (VM_PAGE_IS_FREE(m)) 2015 panic("vm_page_free: freeing free page %p", m); 2016 else if (m->busy != 0) 2017 panic("vm_page_free: freeing busy page %p", m); 2018 2019 /* 2020 * Unqueue, then remove page. Note that we cannot destroy 2021 * the page here because we do not want to call the pager's 2022 * callback routine until after we've put the page on the 2023 * appropriate free queue. 2024 */ 2025 if ((m->oflags & VPO_UNMANAGED) == 0) 2026 vm_pageq_remove(m); 2027 vm_page_remove(m); 2028 2029 /* 2030 * If fictitious remove object association and 2031 * return, otherwise delay object association removal. 2032 */ 2033 if ((m->flags & PG_FICTITIOUS) != 0) { 2034 return; 2035 } 2036 2037 m->valid = 0; 2038 vm_page_undirty(m); 2039 2040 if (m->wire_count != 0) 2041 panic("vm_page_free: freeing wired page %p", m); 2042 if (m->hold_count != 0) { 2043 m->flags &= ~PG_ZERO; 2044 KASSERT((m->flags & PG_UNHOLDFREE) == 0, 2045 ("vm_page_free: freeing PG_UNHOLDFREE page %p", m)); 2046 m->flags |= PG_UNHOLDFREE; 2047 } else { 2048 /* 2049 * Restore the default memory attribute to the page. 2050 */ 2051 if (pmap_page_get_memattr(m) != VM_MEMATTR_DEFAULT) 2052 pmap_page_set_memattr(m, VM_MEMATTR_DEFAULT); 2053 2054 /* 2055 * Insert the page into the physical memory allocator's 2056 * cache/free page queues. 2057 */ 2058 mtx_lock(&vm_page_queue_free_mtx); 2059 m->flags |= PG_FREE; 2060 cnt.v_free_count++; 2061 #if VM_NRESERVLEVEL > 0 2062 if (!vm_reserv_free_page(m)) 2063 #else 2064 if (TRUE) 2065 #endif 2066 vm_phys_free_pages(m, 0); 2067 if ((m->flags & PG_ZERO) != 0) 2068 ++vm_page_zero_count; 2069 else 2070 vm_page_zero_idle_wakeup(); 2071 vm_page_free_wakeup(); 2072 mtx_unlock(&vm_page_queue_free_mtx); 2073 } 2074 } 2075 2076 /* 2077 * vm_page_wire: 2078 * 2079 * Mark this page as wired down by yet 2080 * another map, removing it from paging queues 2081 * as necessary. 2082 * 2083 * If the page is fictitious, then its wire count must remain one. 2084 * 2085 * The page must be locked. 2086 */ 2087 void 2088 vm_page_wire(vm_page_t m) 2089 { 2090 2091 /* 2092 * Only bump the wire statistics if the page is not already wired, 2093 * and only unqueue the page if it is on some queue (if it is unmanaged 2094 * it is already off the queues). 2095 */ 2096 vm_page_lock_assert(m, MA_OWNED); 2097 if ((m->flags & PG_FICTITIOUS) != 0) { 2098 KASSERT(m->wire_count == 1, 2099 ("vm_page_wire: fictitious page %p's wire count isn't one", 2100 m)); 2101 return; 2102 } 2103 if (m->wire_count == 0) { 2104 if ((m->oflags & VPO_UNMANAGED) == 0) 2105 vm_pageq_remove(m); 2106 atomic_add_int(&cnt.v_wire_count, 1); 2107 } 2108 m->wire_count++; 2109 KASSERT(m->wire_count != 0, ("vm_page_wire: wire_count overflow m=%p", m)); 2110 } 2111 2112 /* 2113 * vm_page_unwire: 2114 * 2115 * Release one wiring of the specified page, potentially enabling it to be 2116 * paged again. If paging is enabled, then the value of the parameter 2117 * "activate" determines to which queue the page is added. If "activate" is 2118 * non-zero, then the page is added to the active queue. Otherwise, it is 2119 * added to the inactive queue. 2120 * 2121 * However, unless the page belongs to an object, it is not enqueued because 2122 * it cannot be paged out. 2123 * 2124 * If a page is fictitious, then its wire count must alway be one. 2125 * 2126 * A managed page must be locked. 2127 */ 2128 void 2129 vm_page_unwire(vm_page_t m, int activate) 2130 { 2131 2132 if ((m->oflags & VPO_UNMANAGED) == 0) 2133 vm_page_lock_assert(m, MA_OWNED); 2134 if ((m->flags & PG_FICTITIOUS) != 0) { 2135 KASSERT(m->wire_count == 1, 2136 ("vm_page_unwire: fictitious page %p's wire count isn't one", m)); 2137 return; 2138 } 2139 if (m->wire_count > 0) { 2140 m->wire_count--; 2141 if (m->wire_count == 0) { 2142 atomic_subtract_int(&cnt.v_wire_count, 1); 2143 if ((m->oflags & VPO_UNMANAGED) != 0 || 2144 m->object == NULL) 2145 return; 2146 if (!activate) 2147 m->flags &= ~PG_WINATCFLS; 2148 vm_page_lock_queues(); 2149 vm_page_enqueue(activate ? PQ_ACTIVE : PQ_INACTIVE, m); 2150 vm_page_unlock_queues(); 2151 } 2152 } else 2153 panic("vm_page_unwire: page %p's wire count is zero", m); 2154 } 2155 2156 /* 2157 * Move the specified page to the inactive queue. 2158 * 2159 * Many pages placed on the inactive queue should actually go 2160 * into the cache, but it is difficult to figure out which. What 2161 * we do instead, if the inactive target is well met, is to put 2162 * clean pages at the head of the inactive queue instead of the tail. 2163 * This will cause them to be moved to the cache more quickly and 2164 * if not actively re-referenced, reclaimed more quickly. If we just 2165 * stick these pages at the end of the inactive queue, heavy filesystem 2166 * meta-data accesses can cause an unnecessary paging load on memory bound 2167 * processes. This optimization causes one-time-use metadata to be 2168 * reused more quickly. 2169 * 2170 * Normally athead is 0 resulting in LRU operation. athead is set 2171 * to 1 if we want this page to be 'as if it were placed in the cache', 2172 * except without unmapping it from the process address space. 2173 * 2174 * The page must be locked. 2175 */ 2176 static inline void 2177 _vm_page_deactivate(vm_page_t m, int athead) 2178 { 2179 int queue; 2180 2181 vm_page_lock_assert(m, MA_OWNED); 2182 2183 /* 2184 * Ignore if already inactive. 2185 */ 2186 if ((queue = m->queue) == PQ_INACTIVE) 2187 return; 2188 if (m->wire_count == 0 && (m->oflags & VPO_UNMANAGED) == 0) { 2189 m->flags &= ~PG_WINATCFLS; 2190 vm_page_lock_queues(); 2191 if (queue != PQ_NONE) 2192 vm_page_queue_remove(queue, m); 2193 if (athead) 2194 TAILQ_INSERT_HEAD(&vm_page_queues[PQ_INACTIVE].pl, m, 2195 pageq); 2196 else 2197 TAILQ_INSERT_TAIL(&vm_page_queues[PQ_INACTIVE].pl, m, 2198 pageq); 2199 m->queue = PQ_INACTIVE; 2200 cnt.v_inactive_count++; 2201 vm_page_unlock_queues(); 2202 } 2203 } 2204 2205 /* 2206 * Move the specified page to the inactive queue. 2207 * 2208 * The page must be locked. 2209 */ 2210 void 2211 vm_page_deactivate(vm_page_t m) 2212 { 2213 2214 _vm_page_deactivate(m, 0); 2215 } 2216 2217 /* 2218 * vm_page_try_to_cache: 2219 * 2220 * Returns 0 on failure, 1 on success 2221 */ 2222 int 2223 vm_page_try_to_cache(vm_page_t m) 2224 { 2225 2226 vm_page_lock_assert(m, MA_OWNED); 2227 VM_OBJECT_LOCK_ASSERT(m->object, MA_OWNED); 2228 if (m->dirty || m->hold_count || m->busy || m->wire_count || 2229 (m->oflags & (VPO_BUSY | VPO_UNMANAGED)) != 0) 2230 return (0); 2231 pmap_remove_all(m); 2232 if (m->dirty) 2233 return (0); 2234 vm_page_cache(m); 2235 return (1); 2236 } 2237 2238 /* 2239 * vm_page_try_to_free() 2240 * 2241 * Attempt to free the page. If we cannot free it, we do nothing. 2242 * 1 is returned on success, 0 on failure. 2243 */ 2244 int 2245 vm_page_try_to_free(vm_page_t m) 2246 { 2247 2248 vm_page_lock_assert(m, MA_OWNED); 2249 if (m->object != NULL) 2250 VM_OBJECT_LOCK_ASSERT(m->object, MA_OWNED); 2251 if (m->dirty || m->hold_count || m->busy || m->wire_count || 2252 (m->oflags & (VPO_BUSY | VPO_UNMANAGED)) != 0) 2253 return (0); 2254 pmap_remove_all(m); 2255 if (m->dirty) 2256 return (0); 2257 vm_page_free(m); 2258 return (1); 2259 } 2260 2261 /* 2262 * vm_page_cache 2263 * 2264 * Put the specified page onto the page cache queue (if appropriate). 2265 * 2266 * The object and page must be locked. 2267 */ 2268 void 2269 vm_page_cache(vm_page_t m) 2270 { 2271 vm_object_t object; 2272 vm_page_t next, prev, root; 2273 2274 vm_page_lock_assert(m, MA_OWNED); 2275 object = m->object; 2276 VM_OBJECT_LOCK_ASSERT(object, MA_OWNED); 2277 if ((m->oflags & (VPO_UNMANAGED | VPO_BUSY)) || m->busy || 2278 m->hold_count || m->wire_count) 2279 panic("vm_page_cache: attempting to cache busy page"); 2280 KASSERT(!pmap_page_is_mapped(m), 2281 ("vm_page_cache: page %p is mapped", m)); 2282 KASSERT(m->dirty == 0, ("vm_page_cache: page %p is dirty", m)); 2283 if (m->valid == 0 || object->type == OBJT_DEFAULT || 2284 (object->type == OBJT_SWAP && 2285 !vm_pager_has_page(object, m->pindex, NULL, NULL))) { 2286 /* 2287 * Hypothesis: A cache-elgible page belonging to a 2288 * default object or swap object but without a backing 2289 * store must be zero filled. 2290 */ 2291 vm_page_free(m); 2292 return; 2293 } 2294 KASSERT((m->flags & PG_CACHED) == 0, 2295 ("vm_page_cache: page %p is already cached", m)); 2296 PCPU_INC(cnt.v_tcached); 2297 2298 /* 2299 * Remove the page from the paging queues. 2300 */ 2301 vm_pageq_remove(m); 2302 2303 /* 2304 * Remove the page from the object's collection of resident 2305 * pages. 2306 */ 2307 if ((next = TAILQ_NEXT(m, listq)) != NULL && next->left == m) { 2308 /* 2309 * Since the page's successor in the list is also its parent 2310 * in the tree, its right subtree must be empty. 2311 */ 2312 next->left = m->left; 2313 KASSERT(m->right == NULL, 2314 ("vm_page_cache: page %p has right child", m)); 2315 } else if ((prev = TAILQ_PREV(m, pglist, listq)) != NULL && 2316 prev->right == m) { 2317 /* 2318 * Since the page's predecessor in the list is also its parent 2319 * in the tree, its left subtree must be empty. 2320 */ 2321 KASSERT(m->left == NULL, 2322 ("vm_page_cache: page %p has left child", m)); 2323 prev->right = m->right; 2324 } else { 2325 if (m != object->root) 2326 vm_page_splay(m->pindex, object->root); 2327 if (m->left == NULL) 2328 root = m->right; 2329 else if (m->right == NULL) 2330 root = m->left; 2331 else { 2332 /* 2333 * Move the page's successor to the root, because 2334 * pages are usually removed in ascending order. 2335 */ 2336 if (m->right != next) 2337 vm_page_splay(m->pindex, m->right); 2338 next->left = m->left; 2339 root = next; 2340 } 2341 object->root = root; 2342 } 2343 TAILQ_REMOVE(&object->memq, m, listq); 2344 object->resident_page_count--; 2345 2346 /* 2347 * Restore the default memory attribute to the page. 2348 */ 2349 if (pmap_page_get_memattr(m) != VM_MEMATTR_DEFAULT) 2350 pmap_page_set_memattr(m, VM_MEMATTR_DEFAULT); 2351 2352 /* 2353 * Insert the page into the object's collection of cached pages 2354 * and the physical memory allocator's cache/free page queues. 2355 */ 2356 m->flags &= ~PG_ZERO; 2357 mtx_lock(&vm_page_queue_free_mtx); 2358 m->flags |= PG_CACHED; 2359 cnt.v_cache_count++; 2360 root = object->cache; 2361 if (root == NULL) { 2362 m->left = NULL; 2363 m->right = NULL; 2364 } else { 2365 root = vm_page_splay(m->pindex, root); 2366 if (m->pindex < root->pindex) { 2367 m->left = root->left; 2368 m->right = root; 2369 root->left = NULL; 2370 } else if (__predict_false(m->pindex == root->pindex)) 2371 panic("vm_page_cache: offset already cached"); 2372 else { 2373 m->right = root->right; 2374 m->left = root; 2375 root->right = NULL; 2376 } 2377 } 2378 object->cache = m; 2379 #if VM_NRESERVLEVEL > 0 2380 if (!vm_reserv_free_page(m)) { 2381 #else 2382 if (TRUE) { 2383 #endif 2384 vm_phys_set_pool(VM_FREEPOOL_CACHE, m, 0); 2385 vm_phys_free_pages(m, 0); 2386 } 2387 vm_page_free_wakeup(); 2388 mtx_unlock(&vm_page_queue_free_mtx); 2389 2390 /* 2391 * Increment the vnode's hold count if this is the object's only 2392 * cached page. Decrement the vnode's hold count if this was 2393 * the object's only resident page. 2394 */ 2395 if (object->type == OBJT_VNODE) { 2396 if (root == NULL && object->resident_page_count != 0) 2397 vhold(object->handle); 2398 else if (root != NULL && object->resident_page_count == 0) 2399 vdrop(object->handle); 2400 } 2401 } 2402 2403 /* 2404 * vm_page_dontneed 2405 * 2406 * Cache, deactivate, or do nothing as appropriate. This routine 2407 * is typically used by madvise() MADV_DONTNEED. 2408 * 2409 * Generally speaking we want to move the page into the cache so 2410 * it gets reused quickly. However, this can result in a silly syndrome 2411 * due to the page recycling too quickly. Small objects will not be 2412 * fully cached. On the otherhand, if we move the page to the inactive 2413 * queue we wind up with a problem whereby very large objects 2414 * unnecessarily blow away our inactive and cache queues. 2415 * 2416 * The solution is to move the pages based on a fixed weighting. We 2417 * either leave them alone, deactivate them, or move them to the cache, 2418 * where moving them to the cache has the highest weighting. 2419 * By forcing some pages into other queues we eventually force the 2420 * system to balance the queues, potentially recovering other unrelated 2421 * space from active. The idea is to not force this to happen too 2422 * often. 2423 * 2424 * The object and page must be locked. 2425 */ 2426 void 2427 vm_page_dontneed(vm_page_t m) 2428 { 2429 int dnw; 2430 int head; 2431 2432 vm_page_lock_assert(m, MA_OWNED); 2433 VM_OBJECT_LOCK_ASSERT(m->object, MA_OWNED); 2434 dnw = PCPU_GET(dnweight); 2435 PCPU_INC(dnweight); 2436 2437 /* 2438 * Occasionally leave the page alone. 2439 */ 2440 if ((dnw & 0x01F0) == 0 || m->queue == PQ_INACTIVE) { 2441 if (m->act_count >= ACT_INIT) 2442 --m->act_count; 2443 return; 2444 } 2445 2446 /* 2447 * Clear any references to the page. Otherwise, the page daemon will 2448 * immediately reactivate the page. 2449 * 2450 * Perform the pmap_clear_reference() first. Otherwise, a concurrent 2451 * pmap operation, such as pmap_remove(), could clear a reference in 2452 * the pmap and set PGA_REFERENCED on the page before the 2453 * pmap_clear_reference() had completed. Consequently, the page would 2454 * appear referenced based upon an old reference that occurred before 2455 * this function ran. 2456 */ 2457 pmap_clear_reference(m); 2458 vm_page_aflag_clear(m, PGA_REFERENCED); 2459 2460 if (m->dirty == 0 && pmap_is_modified(m)) 2461 vm_page_dirty(m); 2462 2463 if (m->dirty || (dnw & 0x0070) == 0) { 2464 /* 2465 * Deactivate the page 3 times out of 32. 2466 */ 2467 head = 0; 2468 } else { 2469 /* 2470 * Cache the page 28 times out of every 32. Note that 2471 * the page is deactivated instead of cached, but placed 2472 * at the head of the queue instead of the tail. 2473 */ 2474 head = 1; 2475 } 2476 _vm_page_deactivate(m, head); 2477 } 2478 2479 /* 2480 * Grab a page, waiting until we are waken up due to the page 2481 * changing state. We keep on waiting, if the page continues 2482 * to be in the object. If the page doesn't exist, first allocate it 2483 * and then conditionally zero it. 2484 * 2485 * The caller must always specify the VM_ALLOC_RETRY flag. This is intended 2486 * to facilitate its eventual removal. 2487 * 2488 * This routine may sleep. 2489 * 2490 * The object must be locked on entry. The lock will, however, be released 2491 * and reacquired if the routine sleeps. 2492 */ 2493 vm_page_t 2494 vm_page_grab(vm_object_t object, vm_pindex_t pindex, int allocflags) 2495 { 2496 vm_page_t m; 2497 2498 VM_OBJECT_LOCK_ASSERT(object, MA_OWNED); 2499 KASSERT((allocflags & VM_ALLOC_RETRY) != 0, 2500 ("vm_page_grab: VM_ALLOC_RETRY is required")); 2501 retrylookup: 2502 if ((m = vm_page_lookup(object, pindex)) != NULL) { 2503 if ((m->oflags & VPO_BUSY) != 0 || 2504 ((allocflags & VM_ALLOC_IGN_SBUSY) == 0 && m->busy != 0)) { 2505 /* 2506 * Reference the page before unlocking and 2507 * sleeping so that the page daemon is less 2508 * likely to reclaim it. 2509 */ 2510 vm_page_aflag_set(m, PGA_REFERENCED); 2511 vm_page_sleep(m, "pgrbwt"); 2512 goto retrylookup; 2513 } else { 2514 if ((allocflags & VM_ALLOC_WIRED) != 0) { 2515 vm_page_lock(m); 2516 vm_page_wire(m); 2517 vm_page_unlock(m); 2518 } 2519 if ((allocflags & VM_ALLOC_NOBUSY) == 0) 2520 vm_page_busy(m); 2521 return (m); 2522 } 2523 } 2524 m = vm_page_alloc(object, pindex, allocflags & ~(VM_ALLOC_RETRY | 2525 VM_ALLOC_IGN_SBUSY)); 2526 if (m == NULL) { 2527 VM_OBJECT_UNLOCK(object); 2528 VM_WAIT; 2529 VM_OBJECT_LOCK(object); 2530 goto retrylookup; 2531 } else if (m->valid != 0) 2532 return (m); 2533 if (allocflags & VM_ALLOC_ZERO && (m->flags & PG_ZERO) == 0) 2534 pmap_zero_page(m); 2535 return (m); 2536 } 2537 2538 /* 2539 * Mapping function for valid or dirty bits in a page. 2540 * 2541 * Inputs are required to range within a page. 2542 */ 2543 vm_page_bits_t 2544 vm_page_bits(int base, int size) 2545 { 2546 int first_bit; 2547 int last_bit; 2548 2549 KASSERT( 2550 base + size <= PAGE_SIZE, 2551 ("vm_page_bits: illegal base/size %d/%d", base, size) 2552 ); 2553 2554 if (size == 0) /* handle degenerate case */ 2555 return (0); 2556 2557 first_bit = base >> DEV_BSHIFT; 2558 last_bit = (base + size - 1) >> DEV_BSHIFT; 2559 2560 return (((vm_page_bits_t)2 << last_bit) - 2561 ((vm_page_bits_t)1 << first_bit)); 2562 } 2563 2564 /* 2565 * vm_page_set_valid_range: 2566 * 2567 * Sets portions of a page valid. The arguments are expected 2568 * to be DEV_BSIZE aligned but if they aren't the bitmap is inclusive 2569 * of any partial chunks touched by the range. The invalid portion of 2570 * such chunks will be zeroed. 2571 * 2572 * (base + size) must be less then or equal to PAGE_SIZE. 2573 */ 2574 void 2575 vm_page_set_valid_range(vm_page_t m, int base, int size) 2576 { 2577 int endoff, frag; 2578 2579 VM_OBJECT_LOCK_ASSERT(m->object, MA_OWNED); 2580 if (size == 0) /* handle degenerate case */ 2581 return; 2582 2583 /* 2584 * If the base is not DEV_BSIZE aligned and the valid 2585 * bit is clear, we have to zero out a portion of the 2586 * first block. 2587 */ 2588 if ((frag = base & ~(DEV_BSIZE - 1)) != base && 2589 (m->valid & (1 << (base >> DEV_BSHIFT))) == 0) 2590 pmap_zero_page_area(m, frag, base - frag); 2591 2592 /* 2593 * If the ending offset is not DEV_BSIZE aligned and the 2594 * valid bit is clear, we have to zero out a portion of 2595 * the last block. 2596 */ 2597 endoff = base + size; 2598 if ((frag = endoff & ~(DEV_BSIZE - 1)) != endoff && 2599 (m->valid & (1 << (endoff >> DEV_BSHIFT))) == 0) 2600 pmap_zero_page_area(m, endoff, 2601 DEV_BSIZE - (endoff & (DEV_BSIZE - 1))); 2602 2603 /* 2604 * Assert that no previously invalid block that is now being validated 2605 * is already dirty. 2606 */ 2607 KASSERT((~m->valid & vm_page_bits(base, size) & m->dirty) == 0, 2608 ("vm_page_set_valid_range: page %p is dirty", m)); 2609 2610 /* 2611 * Set valid bits inclusive of any overlap. 2612 */ 2613 m->valid |= vm_page_bits(base, size); 2614 } 2615 2616 /* 2617 * Clear the given bits from the specified page's dirty field. 2618 */ 2619 static __inline void 2620 vm_page_clear_dirty_mask(vm_page_t m, vm_page_bits_t pagebits) 2621 { 2622 uintptr_t addr; 2623 #if PAGE_SIZE < 16384 2624 int shift; 2625 #endif 2626 2627 /* 2628 * If the object is locked and the page is neither VPO_BUSY nor 2629 * write mapped, then the page's dirty field cannot possibly be 2630 * set by a concurrent pmap operation. 2631 */ 2632 VM_OBJECT_LOCK_ASSERT(m->object, MA_OWNED); 2633 if ((m->oflags & VPO_BUSY) == 0 && !pmap_page_is_write_mapped(m)) 2634 m->dirty &= ~pagebits; 2635 else { 2636 /* 2637 * The pmap layer can call vm_page_dirty() without 2638 * holding a distinguished lock. The combination of 2639 * the object's lock and an atomic operation suffice 2640 * to guarantee consistency of the page dirty field. 2641 * 2642 * For PAGE_SIZE == 32768 case, compiler already 2643 * properly aligns the dirty field, so no forcible 2644 * alignment is needed. Only require existence of 2645 * atomic_clear_64 when page size is 32768. 2646 */ 2647 addr = (uintptr_t)&m->dirty; 2648 #if PAGE_SIZE == 32768 2649 atomic_clear_64((uint64_t *)addr, pagebits); 2650 #elif PAGE_SIZE == 16384 2651 atomic_clear_32((uint32_t *)addr, pagebits); 2652 #else /* PAGE_SIZE <= 8192 */ 2653 /* 2654 * Use a trick to perform a 32-bit atomic on the 2655 * containing aligned word, to not depend on the existence 2656 * of atomic_clear_{8, 16}. 2657 */ 2658 shift = addr & (sizeof(uint32_t) - 1); 2659 #if BYTE_ORDER == BIG_ENDIAN 2660 shift = (sizeof(uint32_t) - sizeof(m->dirty) - shift) * NBBY; 2661 #else 2662 shift *= NBBY; 2663 #endif 2664 addr &= ~(sizeof(uint32_t) - 1); 2665 atomic_clear_32((uint32_t *)addr, pagebits << shift); 2666 #endif /* PAGE_SIZE */ 2667 } 2668 } 2669 2670 /* 2671 * vm_page_set_validclean: 2672 * 2673 * Sets portions of a page valid and clean. The arguments are expected 2674 * to be DEV_BSIZE aligned but if they aren't the bitmap is inclusive 2675 * of any partial chunks touched by the range. The invalid portion of 2676 * such chunks will be zero'd. 2677 * 2678 * (base + size) must be less then or equal to PAGE_SIZE. 2679 */ 2680 void 2681 vm_page_set_validclean(vm_page_t m, int base, int size) 2682 { 2683 vm_page_bits_t oldvalid, pagebits; 2684 int endoff, frag; 2685 2686 VM_OBJECT_LOCK_ASSERT(m->object, MA_OWNED); 2687 if (size == 0) /* handle degenerate case */ 2688 return; 2689 2690 /* 2691 * If the base is not DEV_BSIZE aligned and the valid 2692 * bit is clear, we have to zero out a portion of the 2693 * first block. 2694 */ 2695 if ((frag = base & ~(DEV_BSIZE - 1)) != base && 2696 (m->valid & ((vm_page_bits_t)1 << (base >> DEV_BSHIFT))) == 0) 2697 pmap_zero_page_area(m, frag, base - frag); 2698 2699 /* 2700 * If the ending offset is not DEV_BSIZE aligned and the 2701 * valid bit is clear, we have to zero out a portion of 2702 * the last block. 2703 */ 2704 endoff = base + size; 2705 if ((frag = endoff & ~(DEV_BSIZE - 1)) != endoff && 2706 (m->valid & ((vm_page_bits_t)1 << (endoff >> DEV_BSHIFT))) == 0) 2707 pmap_zero_page_area(m, endoff, 2708 DEV_BSIZE - (endoff & (DEV_BSIZE - 1))); 2709 2710 /* 2711 * Set valid, clear dirty bits. If validating the entire 2712 * page we can safely clear the pmap modify bit. We also 2713 * use this opportunity to clear the VPO_NOSYNC flag. If a process 2714 * takes a write fault on a MAP_NOSYNC memory area the flag will 2715 * be set again. 2716 * 2717 * We set valid bits inclusive of any overlap, but we can only 2718 * clear dirty bits for DEV_BSIZE chunks that are fully within 2719 * the range. 2720 */ 2721 oldvalid = m->valid; 2722 pagebits = vm_page_bits(base, size); 2723 m->valid |= pagebits; 2724 #if 0 /* NOT YET */ 2725 if ((frag = base & (DEV_BSIZE - 1)) != 0) { 2726 frag = DEV_BSIZE - frag; 2727 base += frag; 2728 size -= frag; 2729 if (size < 0) 2730 size = 0; 2731 } 2732 pagebits = vm_page_bits(base, size & (DEV_BSIZE - 1)); 2733 #endif 2734 if (base == 0 && size == PAGE_SIZE) { 2735 /* 2736 * The page can only be modified within the pmap if it is 2737 * mapped, and it can only be mapped if it was previously 2738 * fully valid. 2739 */ 2740 if (oldvalid == VM_PAGE_BITS_ALL) 2741 /* 2742 * Perform the pmap_clear_modify() first. Otherwise, 2743 * a concurrent pmap operation, such as 2744 * pmap_protect(), could clear a modification in the 2745 * pmap and set the dirty field on the page before 2746 * pmap_clear_modify() had begun and after the dirty 2747 * field was cleared here. 2748 */ 2749 pmap_clear_modify(m); 2750 m->dirty = 0; 2751 m->oflags &= ~VPO_NOSYNC; 2752 } else if (oldvalid != VM_PAGE_BITS_ALL) 2753 m->dirty &= ~pagebits; 2754 else 2755 vm_page_clear_dirty_mask(m, pagebits); 2756 } 2757 2758 void 2759 vm_page_clear_dirty(vm_page_t m, int base, int size) 2760 { 2761 2762 vm_page_clear_dirty_mask(m, vm_page_bits(base, size)); 2763 } 2764 2765 /* 2766 * vm_page_set_invalid: 2767 * 2768 * Invalidates DEV_BSIZE'd chunks within a page. Both the 2769 * valid and dirty bits for the effected areas are cleared. 2770 */ 2771 void 2772 vm_page_set_invalid(vm_page_t m, int base, int size) 2773 { 2774 vm_page_bits_t bits; 2775 2776 VM_OBJECT_LOCK_ASSERT(m->object, MA_OWNED); 2777 KASSERT((m->oflags & VPO_BUSY) == 0, 2778 ("vm_page_set_invalid: page %p is busy", m)); 2779 bits = vm_page_bits(base, size); 2780 if (m->valid == VM_PAGE_BITS_ALL && bits != 0) 2781 pmap_remove_all(m); 2782 KASSERT(!pmap_page_is_mapped(m), 2783 ("vm_page_set_invalid: page %p is mapped", m)); 2784 m->valid &= ~bits; 2785 m->dirty &= ~bits; 2786 } 2787 2788 /* 2789 * vm_page_zero_invalid() 2790 * 2791 * The kernel assumes that the invalid portions of a page contain 2792 * garbage, but such pages can be mapped into memory by user code. 2793 * When this occurs, we must zero out the non-valid portions of the 2794 * page so user code sees what it expects. 2795 * 2796 * Pages are most often semi-valid when the end of a file is mapped 2797 * into memory and the file's size is not page aligned. 2798 */ 2799 void 2800 vm_page_zero_invalid(vm_page_t m, boolean_t setvalid) 2801 { 2802 int b; 2803 int i; 2804 2805 VM_OBJECT_LOCK_ASSERT(m->object, MA_OWNED); 2806 /* 2807 * Scan the valid bits looking for invalid sections that 2808 * must be zerod. Invalid sub-DEV_BSIZE'd areas ( where the 2809 * valid bit may be set ) have already been zerod by 2810 * vm_page_set_validclean(). 2811 */ 2812 for (b = i = 0; i <= PAGE_SIZE / DEV_BSIZE; ++i) { 2813 if (i == (PAGE_SIZE / DEV_BSIZE) || 2814 (m->valid & ((vm_page_bits_t)1 << i))) { 2815 if (i > b) { 2816 pmap_zero_page_area(m, 2817 b << DEV_BSHIFT, (i - b) << DEV_BSHIFT); 2818 } 2819 b = i + 1; 2820 } 2821 } 2822 2823 /* 2824 * setvalid is TRUE when we can safely set the zero'd areas 2825 * as being valid. We can do this if there are no cache consistancy 2826 * issues. e.g. it is ok to do with UFS, but not ok to do with NFS. 2827 */ 2828 if (setvalid) 2829 m->valid = VM_PAGE_BITS_ALL; 2830 } 2831 2832 /* 2833 * vm_page_is_valid: 2834 * 2835 * Is (partial) page valid? Note that the case where size == 0 2836 * will return FALSE in the degenerate case where the page is 2837 * entirely invalid, and TRUE otherwise. 2838 */ 2839 int 2840 vm_page_is_valid(vm_page_t m, int base, int size) 2841 { 2842 vm_page_bits_t bits; 2843 2844 VM_OBJECT_LOCK_ASSERT(m->object, MA_OWNED); 2845 bits = vm_page_bits(base, size); 2846 if (m->valid && ((m->valid & bits) == bits)) 2847 return 1; 2848 else 2849 return 0; 2850 } 2851 2852 /* 2853 * Set the page's dirty bits if the page is modified. 2854 */ 2855 void 2856 vm_page_test_dirty(vm_page_t m) 2857 { 2858 2859 VM_OBJECT_LOCK_ASSERT(m->object, MA_OWNED); 2860 if (m->dirty != VM_PAGE_BITS_ALL && pmap_is_modified(m)) 2861 vm_page_dirty(m); 2862 } 2863 2864 void 2865 vm_page_lock_KBI(vm_page_t m, const char *file, int line) 2866 { 2867 2868 mtx_lock_flags_(vm_page_lockptr(m), 0, file, line); 2869 } 2870 2871 void 2872 vm_page_unlock_KBI(vm_page_t m, const char *file, int line) 2873 { 2874 2875 mtx_unlock_flags_(vm_page_lockptr(m), 0, file, line); 2876 } 2877 2878 int 2879 vm_page_trylock_KBI(vm_page_t m, const char *file, int line) 2880 { 2881 2882 return (mtx_trylock_flags_(vm_page_lockptr(m), 0, file, line)); 2883 } 2884 2885 #if defined(INVARIANTS) || defined(INVARIANT_SUPPORT) 2886 void 2887 vm_page_lock_assert_KBI(vm_page_t m, int a, const char *file, int line) 2888 { 2889 2890 mtx_assert_(vm_page_lockptr(m), a, file, line); 2891 } 2892 #endif 2893 2894 int so_zerocp_fullpage = 0; 2895 2896 /* 2897 * Replace the given page with a copy. The copied page assumes 2898 * the portion of the given page's "wire_count" that is not the 2899 * responsibility of this copy-on-write mechanism. 2900 * 2901 * The object containing the given page must have a non-zero 2902 * paging-in-progress count and be locked. 2903 */ 2904 void 2905 vm_page_cowfault(vm_page_t m) 2906 { 2907 vm_page_t mnew; 2908 vm_object_t object; 2909 vm_pindex_t pindex; 2910 2911 vm_page_lock_assert(m, MA_OWNED); 2912 object = m->object; 2913 VM_OBJECT_LOCK_ASSERT(object, MA_OWNED); 2914 KASSERT(object->paging_in_progress != 0, 2915 ("vm_page_cowfault: object %p's paging-in-progress count is zero.", 2916 object)); 2917 pindex = m->pindex; 2918 2919 retry_alloc: 2920 pmap_remove_all(m); 2921 vm_page_remove(m); 2922 mnew = vm_page_alloc(object, pindex, VM_ALLOC_NORMAL | VM_ALLOC_NOBUSY); 2923 if (mnew == NULL) { 2924 vm_page_insert(m, object, pindex); 2925 vm_page_unlock(m); 2926 VM_OBJECT_UNLOCK(object); 2927 VM_WAIT; 2928 VM_OBJECT_LOCK(object); 2929 if (m == vm_page_lookup(object, pindex)) { 2930 vm_page_lock(m); 2931 goto retry_alloc; 2932 } else { 2933 /* 2934 * Page disappeared during the wait. 2935 */ 2936 return; 2937 } 2938 } 2939 2940 if (m->cow == 0) { 2941 /* 2942 * check to see if we raced with an xmit complete when 2943 * waiting to allocate a page. If so, put things back 2944 * the way they were 2945 */ 2946 vm_page_unlock(m); 2947 vm_page_lock(mnew); 2948 vm_page_free(mnew); 2949 vm_page_unlock(mnew); 2950 vm_page_insert(m, object, pindex); 2951 } else { /* clear COW & copy page */ 2952 if (!so_zerocp_fullpage) 2953 pmap_copy_page(m, mnew); 2954 mnew->valid = VM_PAGE_BITS_ALL; 2955 vm_page_dirty(mnew); 2956 mnew->wire_count = m->wire_count - m->cow; 2957 m->wire_count = m->cow; 2958 vm_page_unlock(m); 2959 } 2960 } 2961 2962 void 2963 vm_page_cowclear(vm_page_t m) 2964 { 2965 2966 vm_page_lock_assert(m, MA_OWNED); 2967 if (m->cow) { 2968 m->cow--; 2969 /* 2970 * let vm_fault add back write permission lazily 2971 */ 2972 } 2973 /* 2974 * sf_buf_free() will free the page, so we needn't do it here 2975 */ 2976 } 2977 2978 int 2979 vm_page_cowsetup(vm_page_t m) 2980 { 2981 2982 vm_page_lock_assert(m, MA_OWNED); 2983 if ((m->flags & PG_FICTITIOUS) != 0 || 2984 (m->oflags & VPO_UNMANAGED) != 0 || 2985 m->cow == USHRT_MAX - 1 || !VM_OBJECT_TRYLOCK(m->object)) 2986 return (EBUSY); 2987 m->cow++; 2988 pmap_remove_write(m); 2989 VM_OBJECT_UNLOCK(m->object); 2990 return (0); 2991 } 2992 2993 #ifdef INVARIANTS 2994 void 2995 vm_page_object_lock_assert(vm_page_t m) 2996 { 2997 2998 /* 2999 * Certain of the page's fields may only be modified by the 3000 * holder of the containing object's lock or the setter of the 3001 * page's VPO_BUSY flag. Unfortunately, the setter of the 3002 * VPO_BUSY flag is not recorded, and thus cannot be checked 3003 * here. 3004 */ 3005 if (m->object != NULL && (m->oflags & VPO_BUSY) == 0) 3006 VM_OBJECT_LOCK_ASSERT(m->object, MA_OWNED); 3007 } 3008 #endif 3009 3010 #include "opt_ddb.h" 3011 #ifdef DDB 3012 #include <sys/kernel.h> 3013 3014 #include <ddb/ddb.h> 3015 3016 DB_SHOW_COMMAND(page, vm_page_print_page_info) 3017 { 3018 db_printf("cnt.v_free_count: %d\n", cnt.v_free_count); 3019 db_printf("cnt.v_cache_count: %d\n", cnt.v_cache_count); 3020 db_printf("cnt.v_inactive_count: %d\n", cnt.v_inactive_count); 3021 db_printf("cnt.v_active_count: %d\n", cnt.v_active_count); 3022 db_printf("cnt.v_wire_count: %d\n", cnt.v_wire_count); 3023 db_printf("cnt.v_free_reserved: %d\n", cnt.v_free_reserved); 3024 db_printf("cnt.v_free_min: %d\n", cnt.v_free_min); 3025 db_printf("cnt.v_free_target: %d\n", cnt.v_free_target); 3026 db_printf("cnt.v_cache_min: %d\n", cnt.v_cache_min); 3027 db_printf("cnt.v_inactive_target: %d\n", cnt.v_inactive_target); 3028 } 3029 3030 DB_SHOW_COMMAND(pageq, vm_page_print_pageq_info) 3031 { 3032 3033 db_printf("PQ_FREE:"); 3034 db_printf(" %d", cnt.v_free_count); 3035 db_printf("\n"); 3036 3037 db_printf("PQ_CACHE:"); 3038 db_printf(" %d", cnt.v_cache_count); 3039 db_printf("\n"); 3040 3041 db_printf("PQ_ACTIVE: %d, PQ_INACTIVE: %d\n", 3042 *vm_page_queues[PQ_ACTIVE].cnt, 3043 *vm_page_queues[PQ_INACTIVE].cnt); 3044 } 3045 #endif /* DDB */ 3046