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