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 vpglocks vm_page_queue_lock; 120 struct vpglocks vm_page_queue_free_lock; 121 122 struct vpglocks pa_lock[PA_LOCK_COUNT]; 123 124 vm_page_t vm_page_array = 0; 125 int vm_page_array_size = 0; 126 long first_page = 0; 127 int vm_page_zero_count = 0; 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 locks. 296 */ 297 mtx_init(&vm_page_queue_mtx, "vm page queue mutex", NULL, MTX_DEF | 298 MTX_RECURSE); 299 mtx_init(&vm_page_queue_free_mtx, "vm page queue free mutex", NULL, 300 MTX_DEF); 301 302 /* Setup page locks. */ 303 for (i = 0; i < PA_LOCK_COUNT; i++) 304 mtx_init(&pa_lock[i].data, "page lock", NULL, MTX_DEF); 305 306 /* 307 * Initialize the queue headers for the hold queue, the active queue, 308 * and the inactive queue. 309 */ 310 for (i = 0; i < PQ_COUNT; i++) 311 TAILQ_INIT(&vm_page_queues[i].pl); 312 vm_page_queues[PQ_INACTIVE].cnt = &cnt.v_inactive_count; 313 vm_page_queues[PQ_ACTIVE].cnt = &cnt.v_active_count; 314 vm_page_queues[PQ_HOLD].cnt = &cnt.v_active_count; 315 316 /* 317 * Allocate memory for use when boot strapping the kernel memory 318 * allocator. 319 */ 320 new_end = end - (boot_pages * UMA_SLAB_SIZE); 321 new_end = trunc_page(new_end); 322 mapped = pmap_map(&vaddr, new_end, end, 323 VM_PROT_READ | VM_PROT_WRITE); 324 bzero((void *)mapped, end - new_end); 325 uma_startup((void *)mapped, boot_pages); 326 327 #if defined(__amd64__) || defined(__i386__) || defined(__arm__) || \ 328 defined(__mips__) 329 /* 330 * Allocate a bitmap to indicate that a random physical page 331 * needs to be included in a minidump. 332 * 333 * The amd64 port needs this to indicate which direct map pages 334 * need to be dumped, via calls to dump_add_page()/dump_drop_page(). 335 * 336 * However, i386 still needs this workspace internally within the 337 * minidump code. In theory, they are not needed on i386, but are 338 * included should the sf_buf code decide to use them. 339 */ 340 last_pa = 0; 341 for (i = 0; dump_avail[i + 1] != 0; i += 2) 342 if (dump_avail[i + 1] > last_pa) 343 last_pa = dump_avail[i + 1]; 344 page_range = last_pa / PAGE_SIZE; 345 vm_page_dump_size = round_page(roundup2(page_range, NBBY) / NBBY); 346 new_end -= vm_page_dump_size; 347 vm_page_dump = (void *)(uintptr_t)pmap_map(&vaddr, new_end, 348 new_end + vm_page_dump_size, VM_PROT_READ | VM_PROT_WRITE); 349 bzero((void *)vm_page_dump, vm_page_dump_size); 350 #endif 351 #ifdef __amd64__ 352 /* 353 * Request that the physical pages underlying the message buffer be 354 * included in a crash dump. Since the message buffer is accessed 355 * through the direct map, they are not automatically included. 356 */ 357 pa = DMAP_TO_PHYS((vm_offset_t)msgbufp->msg_ptr); 358 last_pa = pa + round_page(msgbufsize); 359 while (pa < last_pa) { 360 dump_add_page(pa); 361 pa += PAGE_SIZE; 362 } 363 #endif 364 /* 365 * Compute the number of pages of memory that will be available for 366 * use (taking into account the overhead of a page structure per 367 * page). 368 */ 369 first_page = low_water / PAGE_SIZE; 370 #ifdef VM_PHYSSEG_SPARSE 371 page_range = 0; 372 for (i = 0; phys_avail[i + 1] != 0; i += 2) 373 page_range += atop(phys_avail[i + 1] - phys_avail[i]); 374 #elif defined(VM_PHYSSEG_DENSE) 375 page_range = high_water / PAGE_SIZE - first_page; 376 #else 377 #error "Either VM_PHYSSEG_DENSE or VM_PHYSSEG_SPARSE must be defined." 378 #endif 379 end = new_end; 380 381 /* 382 * Reserve an unmapped guard page to trap access to vm_page_array[-1]. 383 */ 384 vaddr += PAGE_SIZE; 385 386 /* 387 * Initialize the mem entry structures now, and put them in the free 388 * queue. 389 */ 390 new_end = trunc_page(end - page_range * sizeof(struct vm_page)); 391 mapped = pmap_map(&vaddr, new_end, end, 392 VM_PROT_READ | VM_PROT_WRITE); 393 vm_page_array = (vm_page_t) mapped; 394 #if VM_NRESERVLEVEL > 0 395 /* 396 * Allocate memory for the reservation management system's data 397 * structures. 398 */ 399 new_end = vm_reserv_startup(&vaddr, new_end, high_water); 400 #endif 401 #if defined(__amd64__) || defined(__mips__) 402 /* 403 * pmap_map on amd64 and mips can come out of the direct-map, not kvm 404 * like i386, so the pages must be tracked for a crashdump to include 405 * this data. This includes the vm_page_array and the early UMA 406 * bootstrap pages. 407 */ 408 for (pa = new_end; pa < phys_avail[biggestone + 1]; pa += PAGE_SIZE) 409 dump_add_page(pa); 410 #endif 411 phys_avail[biggestone + 1] = new_end; 412 413 /* 414 * Clear all of the page structures 415 */ 416 bzero((caddr_t) vm_page_array, page_range * sizeof(struct vm_page)); 417 for (i = 0; i < page_range; i++) 418 vm_page_array[i].order = VM_NFREEORDER; 419 vm_page_array_size = page_range; 420 421 /* 422 * Initialize the physical memory allocator. 423 */ 424 vm_phys_init(); 425 426 /* 427 * Add every available physical page that is not blacklisted to 428 * the free lists. 429 */ 430 cnt.v_page_count = 0; 431 cnt.v_free_count = 0; 432 list = getenv("vm.blacklist"); 433 for (i = 0; phys_avail[i + 1] != 0; i += 2) { 434 pa = phys_avail[i]; 435 last_pa = phys_avail[i + 1]; 436 while (pa < last_pa) { 437 if (list != NULL && 438 vm_page_blacklist_lookup(list, pa)) 439 printf("Skipping page with pa 0x%jx\n", 440 (uintmax_t)pa); 441 else 442 vm_phys_add_page(pa); 443 pa += PAGE_SIZE; 444 } 445 } 446 freeenv(list); 447 #if VM_NRESERVLEVEL > 0 448 /* 449 * Initialize the reservation management system. 450 */ 451 vm_reserv_init(); 452 #endif 453 return (vaddr); 454 } 455 456 457 CTASSERT(offsetof(struct vm_page, aflags) % sizeof(uint32_t) == 0); 458 459 void 460 vm_page_aflag_set(vm_page_t m, uint8_t bits) 461 { 462 uint32_t *addr, val; 463 464 /* 465 * The PGA_WRITEABLE flag can only be set if the page is managed and 466 * VPO_BUSY. Currently, this flag is only set by pmap_enter(). 467 */ 468 KASSERT((bits & PGA_WRITEABLE) == 0 || 469 (m->oflags & (VPO_UNMANAGED | VPO_BUSY)) == VPO_BUSY, 470 ("PGA_WRITEABLE and !VPO_BUSY")); 471 472 /* 473 * We want to use atomic updates for m->aflags, which is a 474 * byte wide. Not all architectures provide atomic operations 475 * on the single-byte destination. Punt and access the whole 476 * 4-byte word with an atomic update. Parallel non-atomic 477 * updates to the fields included in the update by proximity 478 * are handled properly by atomics. 479 */ 480 addr = (void *)&m->aflags; 481 MPASS(((uintptr_t)addr & (sizeof(uint32_t) - 1)) == 0); 482 val = bits; 483 #if BYTE_ORDER == BIG_ENDIAN 484 val <<= 24; 485 #endif 486 atomic_set_32(addr, val); 487 } 488 489 void 490 vm_page_aflag_clear(vm_page_t m, uint8_t bits) 491 { 492 uint32_t *addr, val; 493 494 /* 495 * The PGA_REFERENCED flag can only be cleared if the object 496 * containing the page is locked. 497 */ 498 KASSERT((bits & PGA_REFERENCED) == 0 || VM_OBJECT_LOCKED(m->object), 499 ("PGA_REFERENCED and !VM_OBJECT_LOCKED")); 500 501 /* 502 * See the comment in vm_page_aflag_set(). 503 */ 504 addr = (void *)&m->aflags; 505 MPASS(((uintptr_t)addr & (sizeof(uint32_t) - 1)) == 0); 506 val = bits; 507 #if BYTE_ORDER == BIG_ENDIAN 508 val <<= 24; 509 #endif 510 atomic_clear_32(addr, val); 511 } 512 513 void 514 vm_page_reference(vm_page_t m) 515 { 516 517 vm_page_aflag_set(m, PGA_REFERENCED); 518 } 519 520 void 521 vm_page_busy(vm_page_t m) 522 { 523 524 VM_OBJECT_LOCK_ASSERT(m->object, MA_OWNED); 525 KASSERT((m->oflags & VPO_BUSY) == 0, 526 ("vm_page_busy: page already busy!!!")); 527 m->oflags |= VPO_BUSY; 528 } 529 530 /* 531 * vm_page_flash: 532 * 533 * wakeup anyone waiting for the page. 534 */ 535 void 536 vm_page_flash(vm_page_t m) 537 { 538 539 VM_OBJECT_LOCK_ASSERT(m->object, MA_OWNED); 540 if (m->oflags & VPO_WANTED) { 541 m->oflags &= ~VPO_WANTED; 542 wakeup(m); 543 } 544 } 545 546 /* 547 * vm_page_wakeup: 548 * 549 * clear the VPO_BUSY flag and wakeup anyone waiting for the 550 * page. 551 * 552 */ 553 void 554 vm_page_wakeup(vm_page_t m) 555 { 556 557 VM_OBJECT_LOCK_ASSERT(m->object, MA_OWNED); 558 KASSERT(m->oflags & VPO_BUSY, ("vm_page_wakeup: page not busy!!!")); 559 m->oflags &= ~VPO_BUSY; 560 vm_page_flash(m); 561 } 562 563 void 564 vm_page_io_start(vm_page_t m) 565 { 566 567 VM_OBJECT_LOCK_ASSERT(m->object, MA_OWNED); 568 m->busy++; 569 } 570 571 void 572 vm_page_io_finish(vm_page_t m) 573 { 574 575 VM_OBJECT_LOCK_ASSERT(m->object, MA_OWNED); 576 KASSERT(m->busy > 0, ("vm_page_io_finish: page %p is not busy", m)); 577 m->busy--; 578 if (m->busy == 0) 579 vm_page_flash(m); 580 } 581 582 /* 583 * Keep page from being freed by the page daemon 584 * much of the same effect as wiring, except much lower 585 * overhead and should be used only for *very* temporary 586 * holding ("wiring"). 587 */ 588 void 589 vm_page_hold(vm_page_t mem) 590 { 591 592 vm_page_lock_assert(mem, MA_OWNED); 593 mem->hold_count++; 594 } 595 596 void 597 vm_page_unhold(vm_page_t mem) 598 { 599 600 vm_page_lock_assert(mem, MA_OWNED); 601 --mem->hold_count; 602 KASSERT(mem->hold_count >= 0, ("vm_page_unhold: hold count < 0!!!")); 603 if (mem->hold_count == 0 && mem->queue == PQ_HOLD) 604 vm_page_free_toq(mem); 605 } 606 607 /* 608 * vm_page_unhold_pages: 609 * 610 * Unhold each of the pages that is referenced by the given array. 611 */ 612 void 613 vm_page_unhold_pages(vm_page_t *ma, int count) 614 { 615 struct mtx *mtx, *new_mtx; 616 617 mtx = NULL; 618 for (; count != 0; count--) { 619 /* 620 * Avoid releasing and reacquiring the same page lock. 621 */ 622 new_mtx = vm_page_lockptr(*ma); 623 if (mtx != new_mtx) { 624 if (mtx != NULL) 625 mtx_unlock(mtx); 626 mtx = new_mtx; 627 mtx_lock(mtx); 628 } 629 vm_page_unhold(*ma); 630 ma++; 631 } 632 if (mtx != NULL) 633 mtx_unlock(mtx); 634 } 635 636 /* 637 * vm_page_getfake: 638 * 639 * Create a fictitious page with the specified physical address and 640 * memory attribute. The memory attribute is the only the machine- 641 * dependent aspect of a fictitious page that must be initialized. 642 */ 643 vm_page_t 644 vm_page_getfake(vm_paddr_t paddr, vm_memattr_t memattr) 645 { 646 vm_page_t m; 647 648 m = uma_zalloc(fakepg_zone, M_WAITOK | M_ZERO); 649 m->phys_addr = paddr; 650 m->queue = PQ_NONE; 651 /* Fictitious pages don't use "segind". */ 652 m->flags = PG_FICTITIOUS; 653 /* Fictitious pages don't use "order" or "pool". */ 654 m->oflags = VPO_BUSY | VPO_UNMANAGED; 655 m->wire_count = 1; 656 pmap_page_set_memattr(m, memattr); 657 return (m); 658 } 659 660 /* 661 * vm_page_putfake: 662 * 663 * Release a fictitious page. 664 */ 665 void 666 vm_page_putfake(vm_page_t m) 667 { 668 669 KASSERT((m->flags & PG_FICTITIOUS) != 0, 670 ("vm_page_putfake: bad page %p", m)); 671 uma_zfree(fakepg_zone, m); 672 } 673 674 /* 675 * vm_page_updatefake: 676 * 677 * Update the given fictitious page to the specified physical address and 678 * memory attribute. 679 */ 680 void 681 vm_page_updatefake(vm_page_t m, vm_paddr_t paddr, vm_memattr_t memattr) 682 { 683 684 KASSERT((m->flags & PG_FICTITIOUS) != 0, 685 ("vm_page_updatefake: bad page %p", m)); 686 m->phys_addr = paddr; 687 pmap_page_set_memattr(m, memattr); 688 } 689 690 /* 691 * vm_page_free: 692 * 693 * Free a page. 694 */ 695 void 696 vm_page_free(vm_page_t m) 697 { 698 699 m->flags &= ~PG_ZERO; 700 vm_page_free_toq(m); 701 } 702 703 /* 704 * vm_page_free_zero: 705 * 706 * Free a page to the zerod-pages queue 707 */ 708 void 709 vm_page_free_zero(vm_page_t m) 710 { 711 712 m->flags |= PG_ZERO; 713 vm_page_free_toq(m); 714 } 715 716 /* 717 * vm_page_sleep: 718 * 719 * Sleep and release the page and page queues locks. 720 * 721 * The object containing the given page must be locked. 722 */ 723 void 724 vm_page_sleep(vm_page_t m, const char *msg) 725 { 726 727 VM_OBJECT_LOCK_ASSERT(m->object, MA_OWNED); 728 if (mtx_owned(&vm_page_queue_mtx)) 729 vm_page_unlock_queues(); 730 if (mtx_owned(vm_page_lockptr(m))) 731 vm_page_unlock(m); 732 733 /* 734 * It's possible that while we sleep, the page will get 735 * unbusied and freed. If we are holding the object 736 * lock, we will assume we hold a reference to the object 737 * such that even if m->object changes, we can re-lock 738 * it. 739 */ 740 m->oflags |= VPO_WANTED; 741 msleep(m, VM_OBJECT_MTX(m->object), PVM, msg, 0); 742 } 743 744 /* 745 * vm_page_dirty: 746 * 747 * Set all bits in the page's dirty field. 748 * 749 * The object containing the specified page must be locked if the 750 * call is made from the machine-independent layer. 751 * 752 * See vm_page_clear_dirty_mask(). 753 */ 754 void 755 vm_page_dirty(vm_page_t m) 756 { 757 758 KASSERT((m->flags & PG_CACHED) == 0, 759 ("vm_page_dirty: page in cache!")); 760 KASSERT(!VM_PAGE_IS_FREE(m), 761 ("vm_page_dirty: page is free!")); 762 KASSERT(m->valid == VM_PAGE_BITS_ALL, 763 ("vm_page_dirty: page is invalid!")); 764 m->dirty = VM_PAGE_BITS_ALL; 765 } 766 767 /* 768 * vm_page_splay: 769 * 770 * Implements Sleator and Tarjan's top-down splay algorithm. Returns 771 * the vm_page containing the given pindex. If, however, that 772 * pindex is not found in the vm_object, returns a vm_page that is 773 * adjacent to the pindex, coming before or after it. 774 */ 775 vm_page_t 776 vm_page_splay(vm_pindex_t pindex, vm_page_t root) 777 { 778 struct vm_page dummy; 779 vm_page_t lefttreemax, righttreemin, y; 780 781 if (root == NULL) 782 return (root); 783 lefttreemax = righttreemin = &dummy; 784 for (;; root = y) { 785 if (pindex < root->pindex) { 786 if ((y = root->left) == NULL) 787 break; 788 if (pindex < y->pindex) { 789 /* Rotate right. */ 790 root->left = y->right; 791 y->right = root; 792 root = y; 793 if ((y = root->left) == NULL) 794 break; 795 } 796 /* Link into the new root's right tree. */ 797 righttreemin->left = root; 798 righttreemin = root; 799 } else if (pindex > root->pindex) { 800 if ((y = root->right) == NULL) 801 break; 802 if (pindex > y->pindex) { 803 /* Rotate left. */ 804 root->right = y->left; 805 y->left = root; 806 root = y; 807 if ((y = root->right) == NULL) 808 break; 809 } 810 /* Link into the new root's left tree. */ 811 lefttreemax->right = root; 812 lefttreemax = root; 813 } else 814 break; 815 } 816 /* Assemble the new root. */ 817 lefttreemax->right = root->left; 818 righttreemin->left = root->right; 819 root->left = dummy.right; 820 root->right = dummy.left; 821 return (root); 822 } 823 824 /* 825 * vm_page_insert: [ internal use only ] 826 * 827 * Inserts the given mem entry into the object and object list. 828 * 829 * The pagetables are not updated but will presumably fault the page 830 * in if necessary, or if a kernel page the caller will at some point 831 * enter the page into the kernel's pmap. We are not allowed to block 832 * here so we *can't* do this anyway. 833 * 834 * The object and page must be locked. 835 * This routine may not block. 836 */ 837 void 838 vm_page_insert(vm_page_t m, vm_object_t object, vm_pindex_t pindex) 839 { 840 vm_page_t root; 841 842 VM_OBJECT_LOCK_ASSERT(object, MA_OWNED); 843 if (m->object != NULL) 844 panic("vm_page_insert: page already inserted"); 845 846 /* 847 * Record the object/offset pair in this page 848 */ 849 m->object = object; 850 m->pindex = pindex; 851 852 /* 853 * Now link into the object's ordered list of backed pages. 854 */ 855 root = object->root; 856 if (root == NULL) { 857 m->left = NULL; 858 m->right = NULL; 859 TAILQ_INSERT_TAIL(&object->memq, m, listq); 860 } else { 861 root = vm_page_splay(pindex, root); 862 if (pindex < root->pindex) { 863 m->left = root->left; 864 m->right = root; 865 root->left = NULL; 866 TAILQ_INSERT_BEFORE(root, m, listq); 867 } else if (pindex == root->pindex) 868 panic("vm_page_insert: offset already allocated"); 869 else { 870 m->right = root->right; 871 m->left = root; 872 root->right = NULL; 873 TAILQ_INSERT_AFTER(&object->memq, root, m, listq); 874 } 875 } 876 object->root = m; 877 878 /* 879 * show that the object has one more resident page. 880 */ 881 object->resident_page_count++; 882 /* 883 * Hold the vnode until the last page is released. 884 */ 885 if (object->resident_page_count == 1 && object->type == OBJT_VNODE) 886 vhold((struct vnode *)object->handle); 887 888 /* 889 * Since we are inserting a new and possibly dirty page, 890 * update the object's OBJ_MIGHTBEDIRTY flag. 891 */ 892 if (m->aflags & PGA_WRITEABLE) 893 vm_object_set_writeable_dirty(object); 894 } 895 896 /* 897 * vm_page_remove: 898 * NOTE: used by device pager as well -wfj 899 * 900 * Removes the given mem entry from the object/offset-page 901 * table and the object page list, but do not invalidate/terminate 902 * the backing store. 903 * 904 * The object and page must be locked. 905 * The underlying pmap entry (if any) is NOT removed here. 906 * This routine may not block. 907 */ 908 void 909 vm_page_remove(vm_page_t m) 910 { 911 vm_object_t object; 912 vm_page_t next, prev, root; 913 914 if ((m->oflags & VPO_UNMANAGED) == 0) 915 vm_page_lock_assert(m, MA_OWNED); 916 if ((object = m->object) == NULL) 917 return; 918 VM_OBJECT_LOCK_ASSERT(object, MA_OWNED); 919 if (m->oflags & VPO_BUSY) { 920 m->oflags &= ~VPO_BUSY; 921 vm_page_flash(m); 922 } 923 924 /* 925 * Now remove from the object's list of backed pages. 926 */ 927 if ((next = TAILQ_NEXT(m, listq)) != NULL && next->left == m) { 928 /* 929 * Since the page's successor in the list is also its parent 930 * in the tree, its right subtree must be empty. 931 */ 932 next->left = m->left; 933 KASSERT(m->right == NULL, 934 ("vm_page_remove: page %p has right child", m)); 935 } else if ((prev = TAILQ_PREV(m, pglist, listq)) != NULL && 936 prev->right == m) { 937 /* 938 * Since the page's predecessor in the list is also its parent 939 * in the tree, its left subtree must be empty. 940 */ 941 KASSERT(m->left == NULL, 942 ("vm_page_remove: page %p has left child", m)); 943 prev->right = m->right; 944 } else { 945 if (m != object->root) 946 vm_page_splay(m->pindex, object->root); 947 if (m->left == NULL) 948 root = m->right; 949 else if (m->right == NULL) 950 root = m->left; 951 else { 952 /* 953 * Move the page's successor to the root, because 954 * pages are usually removed in ascending order. 955 */ 956 if (m->right != next) 957 vm_page_splay(m->pindex, m->right); 958 next->left = m->left; 959 root = next; 960 } 961 object->root = root; 962 } 963 TAILQ_REMOVE(&object->memq, m, listq); 964 965 /* 966 * And show that the object has one fewer resident page. 967 */ 968 object->resident_page_count--; 969 /* 970 * The vnode may now be recycled. 971 */ 972 if (object->resident_page_count == 0 && object->type == OBJT_VNODE) 973 vdrop((struct vnode *)object->handle); 974 975 m->object = NULL; 976 } 977 978 /* 979 * vm_page_lookup: 980 * 981 * Returns the page associated with the object/offset 982 * pair specified; if none is found, NULL is returned. 983 * 984 * The object must be locked. 985 * This routine may not block. 986 * This is a critical path routine 987 */ 988 vm_page_t 989 vm_page_lookup(vm_object_t object, vm_pindex_t pindex) 990 { 991 vm_page_t m; 992 993 VM_OBJECT_LOCK_ASSERT(object, MA_OWNED); 994 if ((m = object->root) != NULL && m->pindex != pindex) { 995 m = vm_page_splay(pindex, m); 996 if ((object->root = m)->pindex != pindex) 997 m = NULL; 998 } 999 return (m); 1000 } 1001 1002 /* 1003 * vm_page_find_least: 1004 * 1005 * Returns the page associated with the object with least pindex 1006 * greater than or equal to the parameter pindex, or NULL. 1007 * 1008 * The object must be locked. 1009 * The routine may not block. 1010 */ 1011 vm_page_t 1012 vm_page_find_least(vm_object_t object, vm_pindex_t pindex) 1013 { 1014 vm_page_t m; 1015 1016 VM_OBJECT_LOCK_ASSERT(object, MA_OWNED); 1017 if ((m = TAILQ_FIRST(&object->memq)) != NULL) { 1018 if (m->pindex < pindex) { 1019 m = vm_page_splay(pindex, object->root); 1020 if ((object->root = m)->pindex < pindex) 1021 m = TAILQ_NEXT(m, listq); 1022 } 1023 } 1024 return (m); 1025 } 1026 1027 /* 1028 * Returns the given page's successor (by pindex) within the object if it is 1029 * resident; if none is found, NULL is returned. 1030 * 1031 * The object must be locked. 1032 */ 1033 vm_page_t 1034 vm_page_next(vm_page_t m) 1035 { 1036 vm_page_t next; 1037 1038 VM_OBJECT_LOCK_ASSERT(m->object, MA_OWNED); 1039 if ((next = TAILQ_NEXT(m, listq)) != NULL && 1040 next->pindex != m->pindex + 1) 1041 next = NULL; 1042 return (next); 1043 } 1044 1045 /* 1046 * Returns the given page's predecessor (by pindex) within the object if it is 1047 * resident; if none is found, NULL is returned. 1048 * 1049 * The object must be locked. 1050 */ 1051 vm_page_t 1052 vm_page_prev(vm_page_t m) 1053 { 1054 vm_page_t prev; 1055 1056 VM_OBJECT_LOCK_ASSERT(m->object, MA_OWNED); 1057 if ((prev = TAILQ_PREV(m, pglist, listq)) != NULL && 1058 prev->pindex != m->pindex - 1) 1059 prev = NULL; 1060 return (prev); 1061 } 1062 1063 /* 1064 * vm_page_rename: 1065 * 1066 * Move the given memory entry from its 1067 * current object to the specified target object/offset. 1068 * 1069 * The object must be locked. 1070 * This routine may not block. 1071 * 1072 * Note: swap associated with the page must be invalidated by the move. We 1073 * have to do this for several reasons: (1) we aren't freeing the 1074 * page, (2) we are dirtying the page, (3) the VM system is probably 1075 * moving the page from object A to B, and will then later move 1076 * the backing store from A to B and we can't have a conflict. 1077 * 1078 * Note: we *always* dirty the page. It is necessary both for the 1079 * fact that we moved it, and because we may be invalidating 1080 * swap. If the page is on the cache, we have to deactivate it 1081 * or vm_page_dirty() will panic. Dirty pages are not allowed 1082 * on the cache. 1083 */ 1084 void 1085 vm_page_rename(vm_page_t m, vm_object_t new_object, vm_pindex_t new_pindex) 1086 { 1087 1088 vm_page_remove(m); 1089 vm_page_insert(m, new_object, new_pindex); 1090 vm_page_dirty(m); 1091 } 1092 1093 /* 1094 * Convert all of the given object's cached pages that have a 1095 * pindex within the given range into free pages. If the value 1096 * zero is given for "end", then the range's upper bound is 1097 * infinity. If the given object is backed by a vnode and it 1098 * transitions from having one or more cached pages to none, the 1099 * vnode's hold count is reduced. 1100 */ 1101 void 1102 vm_page_cache_free(vm_object_t object, vm_pindex_t start, vm_pindex_t end) 1103 { 1104 vm_page_t m, m_next; 1105 boolean_t empty; 1106 1107 mtx_lock(&vm_page_queue_free_mtx); 1108 if (__predict_false(object->cache == NULL)) { 1109 mtx_unlock(&vm_page_queue_free_mtx); 1110 return; 1111 } 1112 m = object->cache = vm_page_splay(start, object->cache); 1113 if (m->pindex < start) { 1114 if (m->right == NULL) 1115 m = NULL; 1116 else { 1117 m_next = vm_page_splay(start, m->right); 1118 m_next->left = m; 1119 m->right = NULL; 1120 m = object->cache = m_next; 1121 } 1122 } 1123 1124 /* 1125 * At this point, "m" is either (1) a reference to the page 1126 * with the least pindex that is greater than or equal to 1127 * "start" or (2) NULL. 1128 */ 1129 for (; m != NULL && (m->pindex < end || end == 0); m = m_next) { 1130 /* 1131 * Find "m"'s successor and remove "m" from the 1132 * object's cache. 1133 */ 1134 if (m->right == NULL) { 1135 object->cache = m->left; 1136 m_next = NULL; 1137 } else { 1138 m_next = vm_page_splay(start, m->right); 1139 m_next->left = m->left; 1140 object->cache = m_next; 1141 } 1142 /* Convert "m" to a free page. */ 1143 m->object = NULL; 1144 m->valid = 0; 1145 /* Clear PG_CACHED and set PG_FREE. */ 1146 m->flags ^= PG_CACHED | PG_FREE; 1147 KASSERT((m->flags & (PG_CACHED | PG_FREE)) == PG_FREE, 1148 ("vm_page_cache_free: page %p has inconsistent flags", m)); 1149 cnt.v_cache_count--; 1150 cnt.v_free_count++; 1151 } 1152 empty = object->cache == NULL; 1153 mtx_unlock(&vm_page_queue_free_mtx); 1154 if (object->type == OBJT_VNODE && empty) 1155 vdrop(object->handle); 1156 } 1157 1158 /* 1159 * Returns the cached page that is associated with the given 1160 * object and offset. If, however, none exists, returns NULL. 1161 * 1162 * The free page queue must be locked. 1163 */ 1164 static inline vm_page_t 1165 vm_page_cache_lookup(vm_object_t object, vm_pindex_t pindex) 1166 { 1167 vm_page_t m; 1168 1169 mtx_assert(&vm_page_queue_free_mtx, MA_OWNED); 1170 if ((m = object->cache) != NULL && m->pindex != pindex) { 1171 m = vm_page_splay(pindex, m); 1172 if ((object->cache = m)->pindex != pindex) 1173 m = NULL; 1174 } 1175 return (m); 1176 } 1177 1178 /* 1179 * Remove the given cached page from its containing object's 1180 * collection of cached pages. 1181 * 1182 * The free page queue must be locked. 1183 */ 1184 void 1185 vm_page_cache_remove(vm_page_t m) 1186 { 1187 vm_object_t object; 1188 vm_page_t root; 1189 1190 mtx_assert(&vm_page_queue_free_mtx, MA_OWNED); 1191 KASSERT((m->flags & PG_CACHED) != 0, 1192 ("vm_page_cache_remove: page %p is not cached", m)); 1193 object = m->object; 1194 if (m != object->cache) { 1195 root = vm_page_splay(m->pindex, object->cache); 1196 KASSERT(root == m, 1197 ("vm_page_cache_remove: page %p is not cached in object %p", 1198 m, object)); 1199 } 1200 if (m->left == NULL) 1201 root = m->right; 1202 else if (m->right == NULL) 1203 root = m->left; 1204 else { 1205 root = vm_page_splay(m->pindex, m->left); 1206 root->right = m->right; 1207 } 1208 object->cache = root; 1209 m->object = NULL; 1210 cnt.v_cache_count--; 1211 } 1212 1213 /* 1214 * Transfer all of the cached pages with offset greater than or 1215 * equal to 'offidxstart' from the original object's cache to the 1216 * new object's cache. However, any cached pages with offset 1217 * greater than or equal to the new object's size are kept in the 1218 * original object. Initially, the new object's cache must be 1219 * empty. Offset 'offidxstart' in the original object must 1220 * correspond to offset zero in the new object. 1221 * 1222 * The new object must be locked. 1223 */ 1224 void 1225 vm_page_cache_transfer(vm_object_t orig_object, vm_pindex_t offidxstart, 1226 vm_object_t new_object) 1227 { 1228 vm_page_t m, m_next; 1229 1230 /* 1231 * Insertion into an object's collection of cached pages 1232 * requires the object to be locked. In contrast, removal does 1233 * not. 1234 */ 1235 VM_OBJECT_LOCK_ASSERT(new_object, MA_OWNED); 1236 KASSERT(new_object->cache == NULL, 1237 ("vm_page_cache_transfer: object %p has cached pages", 1238 new_object)); 1239 mtx_lock(&vm_page_queue_free_mtx); 1240 if ((m = orig_object->cache) != NULL) { 1241 /* 1242 * Transfer all of the pages with offset greater than or 1243 * equal to 'offidxstart' from the original object's 1244 * cache to the new object's cache. 1245 */ 1246 m = vm_page_splay(offidxstart, m); 1247 if (m->pindex < offidxstart) { 1248 orig_object->cache = m; 1249 new_object->cache = m->right; 1250 m->right = NULL; 1251 } else { 1252 orig_object->cache = m->left; 1253 new_object->cache = m; 1254 m->left = NULL; 1255 } 1256 while ((m = new_object->cache) != NULL) { 1257 if ((m->pindex - offidxstart) >= new_object->size) { 1258 /* 1259 * Return all of the cached pages with 1260 * offset greater than or equal to the 1261 * new object's size to the original 1262 * object's cache. 1263 */ 1264 new_object->cache = m->left; 1265 m->left = orig_object->cache; 1266 orig_object->cache = m; 1267 break; 1268 } 1269 m_next = vm_page_splay(m->pindex, m->right); 1270 /* Update the page's object and offset. */ 1271 m->object = new_object; 1272 m->pindex -= offidxstart; 1273 if (m_next == NULL) 1274 break; 1275 m->right = NULL; 1276 m_next->left = m; 1277 new_object->cache = m_next; 1278 } 1279 KASSERT(new_object->cache == NULL || 1280 new_object->type == OBJT_SWAP, 1281 ("vm_page_cache_transfer: object %p's type is incompatible" 1282 " with cached pages", new_object)); 1283 } 1284 mtx_unlock(&vm_page_queue_free_mtx); 1285 } 1286 1287 /* 1288 * vm_page_alloc: 1289 * 1290 * Allocate and return a page that is associated with the specified 1291 * object and offset pair. By default, this page has the flag VPO_BUSY 1292 * set. 1293 * 1294 * The caller must always specify an allocation class. 1295 * 1296 * allocation classes: 1297 * VM_ALLOC_NORMAL normal process request 1298 * VM_ALLOC_SYSTEM system *really* needs a page 1299 * VM_ALLOC_INTERRUPT interrupt time request 1300 * 1301 * optional allocation flags: 1302 * VM_ALLOC_COUNT(number) the number of additional pages that the caller 1303 * intends to allocate 1304 * VM_ALLOC_IFCACHED return page only if it is cached 1305 * VM_ALLOC_IFNOTCACHED return NULL, do not reactivate if the page 1306 * is cached 1307 * VM_ALLOC_NOBUSY do not set the flag VPO_BUSY on the page 1308 * VM_ALLOC_NODUMP do not include the page in a kernel core dump 1309 * VM_ALLOC_NOOBJ page is not associated with an object and 1310 * should not have the flag VPO_BUSY set 1311 * VM_ALLOC_WIRED wire the allocated page 1312 * VM_ALLOC_ZERO prefer a zeroed page 1313 * 1314 * This routine may not sleep. 1315 */ 1316 vm_page_t 1317 vm_page_alloc(vm_object_t object, vm_pindex_t pindex, int req) 1318 { 1319 struct vnode *vp = NULL; 1320 vm_object_t m_object; 1321 vm_page_t m; 1322 int flags, req_class; 1323 1324 KASSERT((object != NULL) == ((req & VM_ALLOC_NOOBJ) == 0), 1325 ("vm_page_alloc: inconsistent object/req")); 1326 if (object != NULL) 1327 VM_OBJECT_LOCK_ASSERT(object, MA_OWNED); 1328 1329 req_class = req & VM_ALLOC_CLASS_MASK; 1330 1331 /* 1332 * The page daemon is allowed to dig deeper into the free page list. 1333 */ 1334 if (curproc == pageproc && req_class != VM_ALLOC_INTERRUPT) 1335 req_class = VM_ALLOC_SYSTEM; 1336 1337 mtx_lock(&vm_page_queue_free_mtx); 1338 if (cnt.v_free_count + cnt.v_cache_count > cnt.v_free_reserved || 1339 (req_class == VM_ALLOC_SYSTEM && 1340 cnt.v_free_count + cnt.v_cache_count > cnt.v_interrupt_free_min) || 1341 (req_class == VM_ALLOC_INTERRUPT && 1342 cnt.v_free_count + cnt.v_cache_count > 0)) { 1343 /* 1344 * Allocate from the free queue if the number of free pages 1345 * exceeds the minimum for the request class. 1346 */ 1347 if (object != NULL && 1348 (m = vm_page_cache_lookup(object, pindex)) != NULL) { 1349 if ((req & VM_ALLOC_IFNOTCACHED) != 0) { 1350 mtx_unlock(&vm_page_queue_free_mtx); 1351 return (NULL); 1352 } 1353 if (vm_phys_unfree_page(m)) 1354 vm_phys_set_pool(VM_FREEPOOL_DEFAULT, m, 0); 1355 #if VM_NRESERVLEVEL > 0 1356 else if (!vm_reserv_reactivate_page(m)) 1357 #else 1358 else 1359 #endif 1360 panic("vm_page_alloc: cache page %p is missing" 1361 " from the free queue", m); 1362 } else if ((req & VM_ALLOC_IFCACHED) != 0) { 1363 mtx_unlock(&vm_page_queue_free_mtx); 1364 return (NULL); 1365 #if VM_NRESERVLEVEL > 0 1366 } else if (object == NULL || object->type == OBJT_DEVICE || 1367 object->type == OBJT_SG || 1368 (object->flags & OBJ_COLORED) == 0 || 1369 (m = vm_reserv_alloc_page(object, pindex)) == NULL) { 1370 #else 1371 } else { 1372 #endif 1373 m = vm_phys_alloc_pages(object != NULL ? 1374 VM_FREEPOOL_DEFAULT : VM_FREEPOOL_DIRECT, 0); 1375 #if VM_NRESERVLEVEL > 0 1376 if (m == NULL && vm_reserv_reclaim_inactive()) { 1377 m = vm_phys_alloc_pages(object != NULL ? 1378 VM_FREEPOOL_DEFAULT : VM_FREEPOOL_DIRECT, 1379 0); 1380 } 1381 #endif 1382 } 1383 } else { 1384 /* 1385 * Not allocatable, give up. 1386 */ 1387 mtx_unlock(&vm_page_queue_free_mtx); 1388 atomic_add_int(&vm_pageout_deficit, 1389 max((u_int)req >> VM_ALLOC_COUNT_SHIFT, 1)); 1390 pagedaemon_wakeup(); 1391 return (NULL); 1392 } 1393 1394 /* 1395 * At this point we had better have found a good page. 1396 */ 1397 KASSERT(m != NULL, ("vm_page_alloc: missing page")); 1398 KASSERT(m->queue == PQ_NONE, 1399 ("vm_page_alloc: page %p has unexpected queue %d", m, m->queue)); 1400 KASSERT(m->wire_count == 0, ("vm_page_alloc: page %p is wired", m)); 1401 KASSERT(m->hold_count == 0, ("vm_page_alloc: page %p is held", m)); 1402 KASSERT(m->busy == 0, ("vm_page_alloc: page %p is busy", m)); 1403 KASSERT(m->dirty == 0, ("vm_page_alloc: page %p is dirty", m)); 1404 KASSERT(pmap_page_get_memattr(m) == VM_MEMATTR_DEFAULT, 1405 ("vm_page_alloc: page %p has unexpected memattr %d", m, 1406 pmap_page_get_memattr(m))); 1407 if ((m->flags & PG_CACHED) != 0) { 1408 KASSERT((m->flags & PG_ZERO) == 0, 1409 ("vm_page_alloc: cached page %p is PG_ZERO", m)); 1410 KASSERT(m->valid != 0, 1411 ("vm_page_alloc: cached page %p is invalid", m)); 1412 if (m->object == object && m->pindex == pindex) 1413 cnt.v_reactivated++; 1414 else 1415 m->valid = 0; 1416 m_object = m->object; 1417 vm_page_cache_remove(m); 1418 if (m_object->type == OBJT_VNODE && m_object->cache == NULL) 1419 vp = m_object->handle; 1420 } else { 1421 KASSERT(VM_PAGE_IS_FREE(m), 1422 ("vm_page_alloc: page %p is not free", m)); 1423 KASSERT(m->valid == 0, 1424 ("vm_page_alloc: free page %p is valid", m)); 1425 cnt.v_free_count--; 1426 } 1427 1428 /* 1429 * Only the PG_ZERO flag is inherited. The PG_CACHED or PG_FREE flag 1430 * must be cleared before the free page queues lock is released. 1431 */ 1432 flags = 0; 1433 if (req & VM_ALLOC_NODUMP) 1434 flags |= PG_NODUMP; 1435 if (m->flags & PG_ZERO) { 1436 vm_page_zero_count--; 1437 if (req & VM_ALLOC_ZERO) 1438 flags = PG_ZERO; 1439 } 1440 m->flags = flags; 1441 mtx_unlock(&vm_page_queue_free_mtx); 1442 m->aflags = 0; 1443 if (object == NULL || object->type == OBJT_PHYS) 1444 m->oflags = VPO_UNMANAGED; 1445 else 1446 m->oflags = 0; 1447 if ((req & (VM_ALLOC_NOBUSY | VM_ALLOC_NOOBJ)) == 0) 1448 m->oflags |= VPO_BUSY; 1449 if (req & VM_ALLOC_WIRED) { 1450 /* 1451 * The page lock is not required for wiring a page until that 1452 * page is inserted into the object. 1453 */ 1454 atomic_add_int(&cnt.v_wire_count, 1); 1455 m->wire_count = 1; 1456 } 1457 m->act_count = 0; 1458 1459 if (object != NULL) { 1460 /* Ignore device objects; the pager sets "memattr" for them. */ 1461 if (object->memattr != VM_MEMATTR_DEFAULT && 1462 object->type != OBJT_DEVICE && object->type != OBJT_SG) 1463 pmap_page_set_memattr(m, object->memattr); 1464 vm_page_insert(m, object, pindex); 1465 } else 1466 m->pindex = pindex; 1467 1468 /* 1469 * The following call to vdrop() must come after the above call 1470 * to vm_page_insert() in case both affect the same object and 1471 * vnode. Otherwise, the affected vnode's hold count could 1472 * temporarily become zero. 1473 */ 1474 if (vp != NULL) 1475 vdrop(vp); 1476 1477 /* 1478 * Don't wakeup too often - wakeup the pageout daemon when 1479 * we would be nearly out of memory. 1480 */ 1481 if (vm_paging_needed()) 1482 pagedaemon_wakeup(); 1483 1484 return (m); 1485 } 1486 1487 /* 1488 * vm_page_alloc_contig: 1489 * 1490 * Allocate a contiguous set of physical pages of the given size "npages" 1491 * from the free lists. All of the physical pages must be at or above 1492 * the given physical address "low" and below the given physical address 1493 * "high". The given value "alignment" determines the alignment of the 1494 * first physical page in the set. If the given value "boundary" is 1495 * non-zero, then the set of physical pages cannot cross any physical 1496 * address boundary that is a multiple of that value. Both "alignment" 1497 * and "boundary" must be a power of two. 1498 * 1499 * If the specified memory attribute, "memattr", is VM_MEMATTR_DEFAULT, 1500 * then the memory attribute setting for the physical pages is configured 1501 * to the object's memory attribute setting. Otherwise, the memory 1502 * attribute setting for the physical pages is configured to "memattr", 1503 * overriding the object's memory attribute setting. However, if the 1504 * object's memory attribute setting is not VM_MEMATTR_DEFAULT, then the 1505 * memory attribute setting for the physical pages cannot be configured 1506 * to VM_MEMATTR_DEFAULT. 1507 * 1508 * The caller must always specify an allocation class. 1509 * 1510 * allocation classes: 1511 * VM_ALLOC_NORMAL normal process request 1512 * VM_ALLOC_SYSTEM system *really* needs a page 1513 * VM_ALLOC_INTERRUPT interrupt time request 1514 * 1515 * optional allocation flags: 1516 * VM_ALLOC_NOBUSY do not set the flag VPO_BUSY on the page 1517 * VM_ALLOC_NOOBJ page is not associated with an object and 1518 * should not have the flag VPO_BUSY set 1519 * VM_ALLOC_WIRED wire the allocated page 1520 * VM_ALLOC_ZERO prefer a zeroed page 1521 * 1522 * This routine may not sleep. 1523 */ 1524 vm_page_t 1525 vm_page_alloc_contig(vm_object_t object, vm_pindex_t pindex, int req, 1526 u_long npages, vm_paddr_t low, vm_paddr_t high, u_long alignment, 1527 vm_paddr_t boundary, vm_memattr_t memattr) 1528 { 1529 struct vnode *drop; 1530 vm_page_t deferred_vdrop_list, m, m_ret; 1531 u_int flags, oflags; 1532 int req_class; 1533 1534 KASSERT((object != NULL) == ((req & VM_ALLOC_NOOBJ) == 0), 1535 ("vm_page_alloc_contig: inconsistent object/req")); 1536 if (object != NULL) { 1537 VM_OBJECT_LOCK_ASSERT(object, MA_OWNED); 1538 KASSERT(object->type == OBJT_PHYS, 1539 ("vm_page_alloc_contig: object %p isn't OBJT_PHYS", 1540 object)); 1541 } 1542 KASSERT(npages > 0, ("vm_page_alloc_contig: npages is zero")); 1543 req_class = req & VM_ALLOC_CLASS_MASK; 1544 1545 /* 1546 * The page daemon is allowed to dig deeper into the free page list. 1547 */ 1548 if (curproc == pageproc && req_class != VM_ALLOC_INTERRUPT) 1549 req_class = VM_ALLOC_SYSTEM; 1550 1551 deferred_vdrop_list = NULL; 1552 mtx_lock(&vm_page_queue_free_mtx); 1553 if (cnt.v_free_count + cnt.v_cache_count >= npages + 1554 cnt.v_free_reserved || (req_class == VM_ALLOC_SYSTEM && 1555 cnt.v_free_count + cnt.v_cache_count >= npages + 1556 cnt.v_interrupt_free_min) || (req_class == VM_ALLOC_INTERRUPT && 1557 cnt.v_free_count + cnt.v_cache_count >= npages)) { 1558 #if VM_NRESERVLEVEL > 0 1559 retry: 1560 if (object == NULL || (object->flags & OBJ_COLORED) == 0 || 1561 (m_ret = vm_reserv_alloc_contig(object, pindex, npages, 1562 low, high, alignment, boundary)) == NULL) 1563 #endif 1564 m_ret = vm_phys_alloc_contig(npages, low, high, 1565 alignment, boundary); 1566 } else { 1567 mtx_unlock(&vm_page_queue_free_mtx); 1568 atomic_add_int(&vm_pageout_deficit, npages); 1569 pagedaemon_wakeup(); 1570 return (NULL); 1571 } 1572 if (m_ret != NULL) 1573 for (m = m_ret; m < &m_ret[npages]; m++) { 1574 drop = vm_page_alloc_init(m); 1575 if (drop != NULL) { 1576 /* 1577 * Enqueue the vnode for deferred vdrop(). 1578 * 1579 * Once the pages are removed from the free 1580 * page list, "pageq" can be safely abused to 1581 * construct a short-lived list of vnodes. 1582 */ 1583 m->pageq.tqe_prev = (void *)drop; 1584 m->pageq.tqe_next = deferred_vdrop_list; 1585 deferred_vdrop_list = m; 1586 } 1587 } 1588 else { 1589 #if VM_NRESERVLEVEL > 0 1590 if (vm_reserv_reclaim_contig(npages, low, high, alignment, 1591 boundary)) 1592 goto retry; 1593 #endif 1594 } 1595 mtx_unlock(&vm_page_queue_free_mtx); 1596 if (m_ret == NULL) 1597 return (NULL); 1598 1599 /* 1600 * Initialize the pages. Only the PG_ZERO flag is inherited. 1601 */ 1602 flags = 0; 1603 if ((req & VM_ALLOC_ZERO) != 0) 1604 flags = PG_ZERO; 1605 if ((req & VM_ALLOC_NODUMP) != 0) 1606 flags |= PG_NODUMP; 1607 if ((req & VM_ALLOC_WIRED) != 0) 1608 atomic_add_int(&cnt.v_wire_count, npages); 1609 oflags = VPO_UNMANAGED; 1610 if (object != NULL) { 1611 if ((req & VM_ALLOC_NOBUSY) == 0) 1612 oflags |= VPO_BUSY; 1613 if (object->memattr != VM_MEMATTR_DEFAULT && 1614 memattr == VM_MEMATTR_DEFAULT) 1615 memattr = object->memattr; 1616 } 1617 for (m = m_ret; m < &m_ret[npages]; m++) { 1618 m->aflags = 0; 1619 m->flags &= flags; 1620 if ((req & VM_ALLOC_WIRED) != 0) 1621 m->wire_count = 1; 1622 /* Unmanaged pages don't use "act_count". */ 1623 m->oflags = oflags; 1624 if (memattr != VM_MEMATTR_DEFAULT) 1625 pmap_page_set_memattr(m, memattr); 1626 if (object != NULL) 1627 vm_page_insert(m, object, pindex); 1628 else 1629 m->pindex = pindex; 1630 pindex++; 1631 } 1632 while (deferred_vdrop_list != NULL) { 1633 vdrop((struct vnode *)deferred_vdrop_list->pageq.tqe_prev); 1634 deferred_vdrop_list = deferred_vdrop_list->pageq.tqe_next; 1635 } 1636 if (vm_paging_needed()) 1637 pagedaemon_wakeup(); 1638 return (m_ret); 1639 } 1640 1641 /* 1642 * Initialize a page that has been freshly dequeued from a freelist. 1643 * The caller has to drop the vnode returned, if it is not NULL. 1644 * 1645 * This function may only be used to initialize unmanaged pages. 1646 * 1647 * To be called with vm_page_queue_free_mtx held. 1648 */ 1649 static struct vnode * 1650 vm_page_alloc_init(vm_page_t m) 1651 { 1652 struct vnode *drop; 1653 vm_object_t m_object; 1654 1655 KASSERT(m->queue == PQ_NONE, 1656 ("vm_page_alloc_init: page %p has unexpected queue %d", 1657 m, m->queue)); 1658 KASSERT(m->wire_count == 0, 1659 ("vm_page_alloc_init: page %p is wired", m)); 1660 KASSERT(m->hold_count == 0, 1661 ("vm_page_alloc_init: page %p is held", m)); 1662 KASSERT(m->busy == 0, 1663 ("vm_page_alloc_init: page %p is busy", m)); 1664 KASSERT(m->dirty == 0, 1665 ("vm_page_alloc_init: page %p is dirty", m)); 1666 KASSERT(pmap_page_get_memattr(m) == VM_MEMATTR_DEFAULT, 1667 ("vm_page_alloc_init: page %p has unexpected memattr %d", 1668 m, pmap_page_get_memattr(m))); 1669 mtx_assert(&vm_page_queue_free_mtx, MA_OWNED); 1670 drop = NULL; 1671 if ((m->flags & PG_CACHED) != 0) { 1672 KASSERT((m->flags & PG_ZERO) == 0, 1673 ("vm_page_alloc_init: cached page %p is PG_ZERO", m)); 1674 m->valid = 0; 1675 m_object = m->object; 1676 vm_page_cache_remove(m); 1677 if (m_object->type == OBJT_VNODE && m_object->cache == NULL) 1678 drop = m_object->handle; 1679 } else { 1680 KASSERT(VM_PAGE_IS_FREE(m), 1681 ("vm_page_alloc_init: page %p is not free", m)); 1682 KASSERT(m->valid == 0, 1683 ("vm_page_alloc_init: free page %p is valid", m)); 1684 cnt.v_free_count--; 1685 if ((m->flags & PG_ZERO) != 0) 1686 vm_page_zero_count--; 1687 } 1688 /* Don't clear the PG_ZERO flag; we'll need it later. */ 1689 m->flags &= PG_ZERO; 1690 return (drop); 1691 } 1692 1693 /* 1694 * vm_page_alloc_freelist: 1695 * 1696 * Allocate a physical page from the specified free page list. 1697 * 1698 * The caller must always specify an allocation class. 1699 * 1700 * allocation classes: 1701 * VM_ALLOC_NORMAL normal process request 1702 * VM_ALLOC_SYSTEM system *really* needs a page 1703 * VM_ALLOC_INTERRUPT interrupt time request 1704 * 1705 * optional allocation flags: 1706 * VM_ALLOC_COUNT(number) the number of additional pages that the caller 1707 * intends to allocate 1708 * VM_ALLOC_WIRED wire the allocated page 1709 * VM_ALLOC_ZERO prefer a zeroed page 1710 * 1711 * This routine may not sleep. 1712 */ 1713 vm_page_t 1714 vm_page_alloc_freelist(int flind, int req) 1715 { 1716 struct vnode *drop; 1717 vm_page_t m; 1718 u_int flags; 1719 int req_class; 1720 1721 req_class = req & VM_ALLOC_CLASS_MASK; 1722 1723 /* 1724 * The page daemon is allowed to dig deeper into the free page list. 1725 */ 1726 if (curproc == pageproc && req_class != VM_ALLOC_INTERRUPT) 1727 req_class = VM_ALLOC_SYSTEM; 1728 1729 /* 1730 * Do not allocate reserved pages unless the req has asked for it. 1731 */ 1732 mtx_lock(&vm_page_queue_free_mtx); 1733 if (cnt.v_free_count + cnt.v_cache_count > cnt.v_free_reserved || 1734 (req_class == VM_ALLOC_SYSTEM && 1735 cnt.v_free_count + cnt.v_cache_count > cnt.v_interrupt_free_min) || 1736 (req_class == VM_ALLOC_INTERRUPT && 1737 cnt.v_free_count + cnt.v_cache_count > 0)) 1738 m = vm_phys_alloc_freelist_pages(flind, VM_FREEPOOL_DIRECT, 0); 1739 else { 1740 mtx_unlock(&vm_page_queue_free_mtx); 1741 atomic_add_int(&vm_pageout_deficit, 1742 max((u_int)req >> VM_ALLOC_COUNT_SHIFT, 1)); 1743 pagedaemon_wakeup(); 1744 return (NULL); 1745 } 1746 if (m == NULL) { 1747 mtx_unlock(&vm_page_queue_free_mtx); 1748 return (NULL); 1749 } 1750 drop = vm_page_alloc_init(m); 1751 mtx_unlock(&vm_page_queue_free_mtx); 1752 1753 /* 1754 * Initialize the page. Only the PG_ZERO flag is inherited. 1755 */ 1756 m->aflags = 0; 1757 flags = 0; 1758 if ((req & VM_ALLOC_ZERO) != 0) 1759 flags = PG_ZERO; 1760 m->flags &= flags; 1761 if ((req & VM_ALLOC_WIRED) != 0) { 1762 /* 1763 * The page lock is not required for wiring a page that does 1764 * not belong to an object. 1765 */ 1766 atomic_add_int(&cnt.v_wire_count, 1); 1767 m->wire_count = 1; 1768 } 1769 /* Unmanaged pages don't use "act_count". */ 1770 m->oflags = VPO_UNMANAGED; 1771 if (drop != NULL) 1772 vdrop(drop); 1773 if (vm_paging_needed()) 1774 pagedaemon_wakeup(); 1775 return (m); 1776 } 1777 1778 /* 1779 * vm_wait: (also see VM_WAIT macro) 1780 * 1781 * Block until free pages are available for allocation 1782 * - Called in various places before memory allocations. 1783 */ 1784 void 1785 vm_wait(void) 1786 { 1787 1788 mtx_lock(&vm_page_queue_free_mtx); 1789 if (curproc == pageproc) { 1790 vm_pageout_pages_needed = 1; 1791 msleep(&vm_pageout_pages_needed, &vm_page_queue_free_mtx, 1792 PDROP | PSWP, "VMWait", 0); 1793 } else { 1794 if (!vm_pages_needed) { 1795 vm_pages_needed = 1; 1796 wakeup(&vm_pages_needed); 1797 } 1798 msleep(&cnt.v_free_count, &vm_page_queue_free_mtx, PDROP | PVM, 1799 "vmwait", 0); 1800 } 1801 } 1802 1803 /* 1804 * vm_waitpfault: (also see VM_WAITPFAULT macro) 1805 * 1806 * Block until free pages are available for allocation 1807 * - Called only in vm_fault so that processes page faulting 1808 * can be easily tracked. 1809 * - Sleeps at a lower priority than vm_wait() so that vm_wait()ing 1810 * processes will be able to grab memory first. Do not change 1811 * this balance without careful testing first. 1812 */ 1813 void 1814 vm_waitpfault(void) 1815 { 1816 1817 mtx_lock(&vm_page_queue_free_mtx); 1818 if (!vm_pages_needed) { 1819 vm_pages_needed = 1; 1820 wakeup(&vm_pages_needed); 1821 } 1822 msleep(&cnt.v_free_count, &vm_page_queue_free_mtx, PDROP | PUSER, 1823 "pfault", 0); 1824 } 1825 1826 /* 1827 * vm_page_requeue: 1828 * 1829 * Move the given page to the tail of its present page queue. 1830 * 1831 * The page queues must be locked. 1832 */ 1833 void 1834 vm_page_requeue(vm_page_t m) 1835 { 1836 struct vpgqueues *vpq; 1837 int queue; 1838 1839 mtx_assert(&vm_page_queue_mtx, MA_OWNED); 1840 queue = m->queue; 1841 KASSERT(queue != PQ_NONE, 1842 ("vm_page_requeue: page %p is not queued", m)); 1843 vpq = &vm_page_queues[queue]; 1844 TAILQ_REMOVE(&vpq->pl, m, pageq); 1845 TAILQ_INSERT_TAIL(&vpq->pl, m, pageq); 1846 } 1847 1848 /* 1849 * vm_page_queue_remove: 1850 * 1851 * Remove the given page from the specified queue. 1852 * 1853 * The page and page queues must be locked. 1854 */ 1855 static __inline void 1856 vm_page_queue_remove(int queue, vm_page_t m) 1857 { 1858 struct vpgqueues *pq; 1859 1860 mtx_assert(&vm_page_queue_mtx, MA_OWNED); 1861 vm_page_lock_assert(m, MA_OWNED); 1862 pq = &vm_page_queues[queue]; 1863 TAILQ_REMOVE(&pq->pl, m, pageq); 1864 (*pq->cnt)--; 1865 } 1866 1867 /* 1868 * vm_pageq_remove: 1869 * 1870 * Remove a page from its queue. 1871 * 1872 * The given page must be locked. 1873 * This routine may not block. 1874 */ 1875 void 1876 vm_pageq_remove(vm_page_t m) 1877 { 1878 int queue; 1879 1880 vm_page_lock_assert(m, MA_OWNED); 1881 if ((queue = m->queue) != PQ_NONE) { 1882 vm_page_lock_queues(); 1883 m->queue = PQ_NONE; 1884 vm_page_queue_remove(queue, m); 1885 vm_page_unlock_queues(); 1886 } 1887 } 1888 1889 /* 1890 * vm_page_enqueue: 1891 * 1892 * Add the given page to the specified queue. 1893 * 1894 * The page queues must be locked. 1895 */ 1896 static void 1897 vm_page_enqueue(int queue, vm_page_t m) 1898 { 1899 struct vpgqueues *vpq; 1900 1901 vpq = &vm_page_queues[queue]; 1902 m->queue = queue; 1903 TAILQ_INSERT_TAIL(&vpq->pl, m, pageq); 1904 ++*vpq->cnt; 1905 } 1906 1907 /* 1908 * vm_page_activate: 1909 * 1910 * Put the specified page on the active list (if appropriate). 1911 * Ensure that act_count is at least ACT_INIT but do not otherwise 1912 * mess with it. 1913 * 1914 * The page must be locked. 1915 * This routine may not block. 1916 */ 1917 void 1918 vm_page_activate(vm_page_t m) 1919 { 1920 int queue; 1921 1922 vm_page_lock_assert(m, MA_OWNED); 1923 VM_OBJECT_LOCK_ASSERT(m->object, MA_OWNED); 1924 if ((queue = m->queue) != PQ_ACTIVE) { 1925 if (m->wire_count == 0 && (m->oflags & VPO_UNMANAGED) == 0) { 1926 if (m->act_count < ACT_INIT) 1927 m->act_count = ACT_INIT; 1928 vm_page_lock_queues(); 1929 if (queue != PQ_NONE) 1930 vm_page_queue_remove(queue, m); 1931 vm_page_enqueue(PQ_ACTIVE, m); 1932 vm_page_unlock_queues(); 1933 } else 1934 KASSERT(queue == PQ_NONE, 1935 ("vm_page_activate: wired page %p is queued", m)); 1936 } else { 1937 if (m->act_count < ACT_INIT) 1938 m->act_count = ACT_INIT; 1939 } 1940 } 1941 1942 /* 1943 * vm_page_free_wakeup: 1944 * 1945 * Helper routine for vm_page_free_toq() and vm_page_cache(). This 1946 * routine is called when a page has been added to the cache or free 1947 * queues. 1948 * 1949 * The page queues must be locked. 1950 * This routine may not block. 1951 */ 1952 static inline void 1953 vm_page_free_wakeup(void) 1954 { 1955 1956 mtx_assert(&vm_page_queue_free_mtx, MA_OWNED); 1957 /* 1958 * if pageout daemon needs pages, then tell it that there are 1959 * some free. 1960 */ 1961 if (vm_pageout_pages_needed && 1962 cnt.v_cache_count + cnt.v_free_count >= cnt.v_pageout_free_min) { 1963 wakeup(&vm_pageout_pages_needed); 1964 vm_pageout_pages_needed = 0; 1965 } 1966 /* 1967 * wakeup processes that are waiting on memory if we hit a 1968 * high water mark. And wakeup scheduler process if we have 1969 * lots of memory. this process will swapin processes. 1970 */ 1971 if (vm_pages_needed && !vm_page_count_min()) { 1972 vm_pages_needed = 0; 1973 wakeup(&cnt.v_free_count); 1974 } 1975 } 1976 1977 /* 1978 * vm_page_free_toq: 1979 * 1980 * Returns the given page to the free list, 1981 * disassociating it with any VM object. 1982 * 1983 * Object and page must be locked prior to entry. 1984 * This routine may not block. 1985 */ 1986 1987 void 1988 vm_page_free_toq(vm_page_t m) 1989 { 1990 1991 if ((m->oflags & VPO_UNMANAGED) == 0) { 1992 vm_page_lock_assert(m, MA_OWNED); 1993 KASSERT(!pmap_page_is_mapped(m), 1994 ("vm_page_free_toq: freeing mapped page %p", m)); 1995 } 1996 PCPU_INC(cnt.v_tfree); 1997 1998 if (VM_PAGE_IS_FREE(m)) 1999 panic("vm_page_free: freeing free page %p", m); 2000 else if (m->busy != 0) 2001 panic("vm_page_free: freeing busy page %p", m); 2002 2003 /* 2004 * unqueue, then remove page. Note that we cannot destroy 2005 * the page here because we do not want to call the pager's 2006 * callback routine until after we've put the page on the 2007 * appropriate free queue. 2008 */ 2009 if ((m->oflags & VPO_UNMANAGED) == 0) 2010 vm_pageq_remove(m); 2011 vm_page_remove(m); 2012 2013 /* 2014 * If fictitious remove object association and 2015 * return, otherwise delay object association removal. 2016 */ 2017 if ((m->flags & PG_FICTITIOUS) != 0) { 2018 return; 2019 } 2020 2021 m->valid = 0; 2022 vm_page_undirty(m); 2023 2024 if (m->wire_count != 0) 2025 panic("vm_page_free: freeing wired page %p", m); 2026 if (m->hold_count != 0) { 2027 m->flags &= ~PG_ZERO; 2028 vm_page_lock_queues(); 2029 vm_page_enqueue(PQ_HOLD, m); 2030 vm_page_unlock_queues(); 2031 } else { 2032 /* 2033 * Restore the default memory attribute to the page. 2034 */ 2035 if (pmap_page_get_memattr(m) != VM_MEMATTR_DEFAULT) 2036 pmap_page_set_memattr(m, VM_MEMATTR_DEFAULT); 2037 2038 /* 2039 * Insert the page into the physical memory allocator's 2040 * cache/free page queues. 2041 */ 2042 mtx_lock(&vm_page_queue_free_mtx); 2043 m->flags |= PG_FREE; 2044 cnt.v_free_count++; 2045 #if VM_NRESERVLEVEL > 0 2046 if (!vm_reserv_free_page(m)) 2047 #else 2048 if (TRUE) 2049 #endif 2050 vm_phys_free_pages(m, 0); 2051 if ((m->flags & PG_ZERO) != 0) 2052 ++vm_page_zero_count; 2053 else 2054 vm_page_zero_idle_wakeup(); 2055 vm_page_free_wakeup(); 2056 mtx_unlock(&vm_page_queue_free_mtx); 2057 } 2058 } 2059 2060 /* 2061 * vm_page_wire: 2062 * 2063 * Mark this page as wired down by yet 2064 * another map, removing it from paging queues 2065 * as necessary. 2066 * 2067 * If the page is fictitious, then its wire count must remain one. 2068 * 2069 * The page must be locked. 2070 * This routine may not block. 2071 */ 2072 void 2073 vm_page_wire(vm_page_t m) 2074 { 2075 2076 /* 2077 * Only bump the wire statistics if the page is not already wired, 2078 * and only unqueue the page if it is on some queue (if it is unmanaged 2079 * it is already off the queues). 2080 */ 2081 vm_page_lock_assert(m, MA_OWNED); 2082 if ((m->flags & PG_FICTITIOUS) != 0) { 2083 KASSERT(m->wire_count == 1, 2084 ("vm_page_wire: fictitious page %p's wire count isn't one", 2085 m)); 2086 return; 2087 } 2088 if (m->wire_count == 0) { 2089 if ((m->oflags & VPO_UNMANAGED) == 0) 2090 vm_pageq_remove(m); 2091 atomic_add_int(&cnt.v_wire_count, 1); 2092 } 2093 m->wire_count++; 2094 KASSERT(m->wire_count != 0, ("vm_page_wire: wire_count overflow m=%p", m)); 2095 } 2096 2097 /* 2098 * vm_page_unwire: 2099 * 2100 * Release one wiring of the specified page, potentially enabling it to be 2101 * paged again. If paging is enabled, then the value of the parameter 2102 * "activate" determines to which queue the page is added. If "activate" is 2103 * non-zero, then the page is added to the active queue. Otherwise, it is 2104 * added to the inactive queue. 2105 * 2106 * However, unless the page belongs to an object, it is not enqueued because 2107 * it cannot be paged out. 2108 * 2109 * If a page is fictitious, then its wire count must alway be one. 2110 * 2111 * A managed page must be locked. 2112 */ 2113 void 2114 vm_page_unwire(vm_page_t m, int activate) 2115 { 2116 2117 if ((m->oflags & VPO_UNMANAGED) == 0) 2118 vm_page_lock_assert(m, MA_OWNED); 2119 if ((m->flags & PG_FICTITIOUS) != 0) { 2120 KASSERT(m->wire_count == 1, 2121 ("vm_page_unwire: fictitious page %p's wire count isn't one", m)); 2122 return; 2123 } 2124 if (m->wire_count > 0) { 2125 m->wire_count--; 2126 if (m->wire_count == 0) { 2127 atomic_subtract_int(&cnt.v_wire_count, 1); 2128 if ((m->oflags & VPO_UNMANAGED) != 0 || 2129 m->object == NULL) 2130 return; 2131 vm_page_lock_queues(); 2132 if (activate) 2133 vm_page_enqueue(PQ_ACTIVE, m); 2134 else { 2135 m->flags &= ~PG_WINATCFLS; 2136 vm_page_enqueue(PQ_INACTIVE, m); 2137 } 2138 vm_page_unlock_queues(); 2139 } 2140 } else 2141 panic("vm_page_unwire: page %p's wire count is zero", m); 2142 } 2143 2144 /* 2145 * Move the specified page to the inactive queue. 2146 * 2147 * Many pages placed on the inactive queue should actually go 2148 * into the cache, but it is difficult to figure out which. What 2149 * we do instead, if the inactive target is well met, is to put 2150 * clean pages at the head of the inactive queue instead of the tail. 2151 * This will cause them to be moved to the cache more quickly and 2152 * if not actively re-referenced, reclaimed more quickly. If we just 2153 * stick these pages at the end of the inactive queue, heavy filesystem 2154 * meta-data accesses can cause an unnecessary paging load on memory bound 2155 * processes. This optimization causes one-time-use metadata to be 2156 * reused more quickly. 2157 * 2158 * Normally athead is 0 resulting in LRU operation. athead is set 2159 * to 1 if we want this page to be 'as if it were placed in the cache', 2160 * except without unmapping it from the process address space. 2161 * 2162 * This routine may not block. 2163 */ 2164 static inline void 2165 _vm_page_deactivate(vm_page_t m, int athead) 2166 { 2167 int queue; 2168 2169 vm_page_lock_assert(m, MA_OWNED); 2170 2171 /* 2172 * Ignore if already inactive. 2173 */ 2174 if ((queue = m->queue) == PQ_INACTIVE) 2175 return; 2176 if (m->wire_count == 0 && (m->oflags & VPO_UNMANAGED) == 0) { 2177 vm_page_lock_queues(); 2178 m->flags &= ~PG_WINATCFLS; 2179 if (queue != PQ_NONE) 2180 vm_page_queue_remove(queue, m); 2181 if (athead) 2182 TAILQ_INSERT_HEAD(&vm_page_queues[PQ_INACTIVE].pl, m, 2183 pageq); 2184 else 2185 TAILQ_INSERT_TAIL(&vm_page_queues[PQ_INACTIVE].pl, m, 2186 pageq); 2187 m->queue = PQ_INACTIVE; 2188 cnt.v_inactive_count++; 2189 vm_page_unlock_queues(); 2190 } 2191 } 2192 2193 /* 2194 * Move the specified page to the inactive queue. 2195 * 2196 * The page must be locked. 2197 */ 2198 void 2199 vm_page_deactivate(vm_page_t m) 2200 { 2201 2202 _vm_page_deactivate(m, 0); 2203 } 2204 2205 /* 2206 * vm_page_try_to_cache: 2207 * 2208 * Returns 0 on failure, 1 on success 2209 */ 2210 int 2211 vm_page_try_to_cache(vm_page_t m) 2212 { 2213 2214 vm_page_lock_assert(m, MA_OWNED); 2215 VM_OBJECT_LOCK_ASSERT(m->object, MA_OWNED); 2216 if (m->dirty || m->hold_count || m->busy || m->wire_count || 2217 (m->oflags & (VPO_BUSY | VPO_UNMANAGED)) != 0) 2218 return (0); 2219 pmap_remove_all(m); 2220 if (m->dirty) 2221 return (0); 2222 vm_page_cache(m); 2223 return (1); 2224 } 2225 2226 /* 2227 * vm_page_try_to_free() 2228 * 2229 * Attempt to free the page. If we cannot free it, we do nothing. 2230 * 1 is returned on success, 0 on failure. 2231 */ 2232 int 2233 vm_page_try_to_free(vm_page_t m) 2234 { 2235 2236 vm_page_lock_assert(m, MA_OWNED); 2237 if (m->object != NULL) 2238 VM_OBJECT_LOCK_ASSERT(m->object, MA_OWNED); 2239 if (m->dirty || m->hold_count || m->busy || m->wire_count || 2240 (m->oflags & (VPO_BUSY | VPO_UNMANAGED)) != 0) 2241 return (0); 2242 pmap_remove_all(m); 2243 if (m->dirty) 2244 return (0); 2245 vm_page_free(m); 2246 return (1); 2247 } 2248 2249 /* 2250 * vm_page_cache 2251 * 2252 * Put the specified page onto the page cache queue (if appropriate). 2253 * 2254 * This routine may not block. 2255 */ 2256 void 2257 vm_page_cache(vm_page_t m) 2258 { 2259 vm_object_t object; 2260 vm_page_t next, prev, root; 2261 2262 vm_page_lock_assert(m, MA_OWNED); 2263 object = m->object; 2264 VM_OBJECT_LOCK_ASSERT(object, MA_OWNED); 2265 if ((m->oflags & (VPO_UNMANAGED | VPO_BUSY)) || m->busy || 2266 m->hold_count || m->wire_count) 2267 panic("vm_page_cache: attempting to cache busy page"); 2268 pmap_remove_all(m); 2269 if (m->dirty != 0) 2270 panic("vm_page_cache: page %p is dirty", m); 2271 if (m->valid == 0 || object->type == OBJT_DEFAULT || 2272 (object->type == OBJT_SWAP && 2273 !vm_pager_has_page(object, m->pindex, NULL, NULL))) { 2274 /* 2275 * Hypothesis: A cache-elgible page belonging to a 2276 * default object or swap object but without a backing 2277 * store must be zero filled. 2278 */ 2279 vm_page_free(m); 2280 return; 2281 } 2282 KASSERT((m->flags & PG_CACHED) == 0, 2283 ("vm_page_cache: page %p is already cached", m)); 2284 PCPU_INC(cnt.v_tcached); 2285 2286 /* 2287 * Remove the page from the paging queues. 2288 */ 2289 vm_pageq_remove(m); 2290 2291 /* 2292 * Remove the page from the object's collection of resident 2293 * pages. 2294 */ 2295 if ((next = TAILQ_NEXT(m, listq)) != NULL && next->left == m) { 2296 /* 2297 * Since the page's successor in the list is also its parent 2298 * in the tree, its right subtree must be empty. 2299 */ 2300 next->left = m->left; 2301 KASSERT(m->right == NULL, 2302 ("vm_page_cache: page %p has right child", m)); 2303 } else if ((prev = TAILQ_PREV(m, pglist, listq)) != NULL && 2304 prev->right == m) { 2305 /* 2306 * Since the page's predecessor in the list is also its parent 2307 * in the tree, its left subtree must be empty. 2308 */ 2309 KASSERT(m->left == NULL, 2310 ("vm_page_cache: page %p has left child", m)); 2311 prev->right = m->right; 2312 } else { 2313 if (m != object->root) 2314 vm_page_splay(m->pindex, object->root); 2315 if (m->left == NULL) 2316 root = m->right; 2317 else if (m->right == NULL) 2318 root = m->left; 2319 else { 2320 /* 2321 * Move the page's successor to the root, because 2322 * pages are usually removed in ascending order. 2323 */ 2324 if (m->right != next) 2325 vm_page_splay(m->pindex, m->right); 2326 next->left = m->left; 2327 root = next; 2328 } 2329 object->root = root; 2330 } 2331 TAILQ_REMOVE(&object->memq, m, listq); 2332 object->resident_page_count--; 2333 2334 /* 2335 * Restore the default memory attribute to the page. 2336 */ 2337 if (pmap_page_get_memattr(m) != VM_MEMATTR_DEFAULT) 2338 pmap_page_set_memattr(m, VM_MEMATTR_DEFAULT); 2339 2340 /* 2341 * Insert the page into the object's collection of cached pages 2342 * and the physical memory allocator's cache/free page queues. 2343 */ 2344 m->flags &= ~PG_ZERO; 2345 mtx_lock(&vm_page_queue_free_mtx); 2346 m->flags |= PG_CACHED; 2347 cnt.v_cache_count++; 2348 root = object->cache; 2349 if (root == NULL) { 2350 m->left = NULL; 2351 m->right = NULL; 2352 } else { 2353 root = vm_page_splay(m->pindex, root); 2354 if (m->pindex < root->pindex) { 2355 m->left = root->left; 2356 m->right = root; 2357 root->left = NULL; 2358 } else if (__predict_false(m->pindex == root->pindex)) 2359 panic("vm_page_cache: offset already cached"); 2360 else { 2361 m->right = root->right; 2362 m->left = root; 2363 root->right = NULL; 2364 } 2365 } 2366 object->cache = m; 2367 #if VM_NRESERVLEVEL > 0 2368 if (!vm_reserv_free_page(m)) { 2369 #else 2370 if (TRUE) { 2371 #endif 2372 vm_phys_set_pool(VM_FREEPOOL_CACHE, m, 0); 2373 vm_phys_free_pages(m, 0); 2374 } 2375 vm_page_free_wakeup(); 2376 mtx_unlock(&vm_page_queue_free_mtx); 2377 2378 /* 2379 * Increment the vnode's hold count if this is the object's only 2380 * cached page. Decrement the vnode's hold count if this was 2381 * the object's only resident page. 2382 */ 2383 if (object->type == OBJT_VNODE) { 2384 if (root == NULL && object->resident_page_count != 0) 2385 vhold(object->handle); 2386 else if (root != NULL && object->resident_page_count == 0) 2387 vdrop(object->handle); 2388 } 2389 } 2390 2391 /* 2392 * vm_page_dontneed 2393 * 2394 * Cache, deactivate, or do nothing as appropriate. This routine 2395 * is typically used by madvise() MADV_DONTNEED. 2396 * 2397 * Generally speaking we want to move the page into the cache so 2398 * it gets reused quickly. However, this can result in a silly syndrome 2399 * due to the page recycling too quickly. Small objects will not be 2400 * fully cached. On the otherhand, if we move the page to the inactive 2401 * queue we wind up with a problem whereby very large objects 2402 * unnecessarily blow away our inactive and cache queues. 2403 * 2404 * The solution is to move the pages based on a fixed weighting. We 2405 * either leave them alone, deactivate them, or move them to the cache, 2406 * where moving them to the cache has the highest weighting. 2407 * By forcing some pages into other queues we eventually force the 2408 * system to balance the queues, potentially recovering other unrelated 2409 * space from active. The idea is to not force this to happen too 2410 * often. 2411 */ 2412 void 2413 vm_page_dontneed(vm_page_t m) 2414 { 2415 int dnw; 2416 int head; 2417 2418 vm_page_lock_assert(m, MA_OWNED); 2419 VM_OBJECT_LOCK_ASSERT(m->object, MA_OWNED); 2420 dnw = PCPU_GET(dnweight); 2421 PCPU_INC(dnweight); 2422 2423 /* 2424 * Occasionally leave the page alone. 2425 */ 2426 if ((dnw & 0x01F0) == 0 || m->queue == PQ_INACTIVE) { 2427 if (m->act_count >= ACT_INIT) 2428 --m->act_count; 2429 return; 2430 } 2431 2432 /* 2433 * Clear any references to the page. Otherwise, the page daemon will 2434 * immediately reactivate the page. 2435 * 2436 * Perform the pmap_clear_reference() first. Otherwise, a concurrent 2437 * pmap operation, such as pmap_remove(), could clear a reference in 2438 * the pmap and set PGA_REFERENCED on the page before the 2439 * pmap_clear_reference() had completed. Consequently, the page would 2440 * appear referenced based upon an old reference that occurred before 2441 * this function ran. 2442 */ 2443 pmap_clear_reference(m); 2444 vm_page_aflag_clear(m, PGA_REFERENCED); 2445 2446 if (m->dirty == 0 && pmap_is_modified(m)) 2447 vm_page_dirty(m); 2448 2449 if (m->dirty || (dnw & 0x0070) == 0) { 2450 /* 2451 * Deactivate the page 3 times out of 32. 2452 */ 2453 head = 0; 2454 } else { 2455 /* 2456 * Cache the page 28 times out of every 32. Note that 2457 * the page is deactivated instead of cached, but placed 2458 * at the head of the queue instead of the tail. 2459 */ 2460 head = 1; 2461 } 2462 _vm_page_deactivate(m, head); 2463 } 2464 2465 /* 2466 * Grab a page, waiting until we are waken up due to the page 2467 * changing state. We keep on waiting, if the page continues 2468 * to be in the object. If the page doesn't exist, first allocate it 2469 * and then conditionally zero it. 2470 * 2471 * The caller must always specify the VM_ALLOC_RETRY flag. This is intended 2472 * to facilitate its eventual removal. 2473 * 2474 * This routine may block. 2475 */ 2476 vm_page_t 2477 vm_page_grab(vm_object_t object, vm_pindex_t pindex, int allocflags) 2478 { 2479 vm_page_t m; 2480 2481 VM_OBJECT_LOCK_ASSERT(object, MA_OWNED); 2482 KASSERT((allocflags & VM_ALLOC_RETRY) != 0, 2483 ("vm_page_grab: VM_ALLOC_RETRY is required")); 2484 retrylookup: 2485 if ((m = vm_page_lookup(object, pindex)) != NULL) { 2486 if ((m->oflags & VPO_BUSY) != 0 || 2487 ((allocflags & VM_ALLOC_IGN_SBUSY) == 0 && m->busy != 0)) { 2488 /* 2489 * Reference the page before unlocking and 2490 * sleeping so that the page daemon is less 2491 * likely to reclaim it. 2492 */ 2493 vm_page_aflag_set(m, PGA_REFERENCED); 2494 vm_page_sleep(m, "pgrbwt"); 2495 goto retrylookup; 2496 } else { 2497 if ((allocflags & VM_ALLOC_WIRED) != 0) { 2498 vm_page_lock(m); 2499 vm_page_wire(m); 2500 vm_page_unlock(m); 2501 } 2502 if ((allocflags & VM_ALLOC_NOBUSY) == 0) 2503 vm_page_busy(m); 2504 return (m); 2505 } 2506 } 2507 m = vm_page_alloc(object, pindex, allocflags & ~(VM_ALLOC_RETRY | 2508 VM_ALLOC_IGN_SBUSY)); 2509 if (m == NULL) { 2510 VM_OBJECT_UNLOCK(object); 2511 VM_WAIT; 2512 VM_OBJECT_LOCK(object); 2513 goto retrylookup; 2514 } else if (m->valid != 0) 2515 return (m); 2516 if (allocflags & VM_ALLOC_ZERO && (m->flags & PG_ZERO) == 0) 2517 pmap_zero_page(m); 2518 return (m); 2519 } 2520 2521 /* 2522 * Mapping function for valid bits or for dirty bits in 2523 * a page. May not block. 2524 * 2525 * Inputs are required to range within a page. 2526 */ 2527 vm_page_bits_t 2528 vm_page_bits(int base, int size) 2529 { 2530 int first_bit; 2531 int last_bit; 2532 2533 KASSERT( 2534 base + size <= PAGE_SIZE, 2535 ("vm_page_bits: illegal base/size %d/%d", base, size) 2536 ); 2537 2538 if (size == 0) /* handle degenerate case */ 2539 return (0); 2540 2541 first_bit = base >> DEV_BSHIFT; 2542 last_bit = (base + size - 1) >> DEV_BSHIFT; 2543 2544 return (((vm_page_bits_t)2 << last_bit) - 2545 ((vm_page_bits_t)1 << first_bit)); 2546 } 2547 2548 /* 2549 * vm_page_set_valid_range: 2550 * 2551 * Sets portions of a page valid. The arguments are expected 2552 * to be DEV_BSIZE aligned but if they aren't the bitmap is inclusive 2553 * of any partial chunks touched by the range. The invalid portion of 2554 * such chunks will be zeroed. 2555 * 2556 * (base + size) must be less then or equal to PAGE_SIZE. 2557 */ 2558 void 2559 vm_page_set_valid_range(vm_page_t m, int base, int size) 2560 { 2561 int endoff, frag; 2562 2563 VM_OBJECT_LOCK_ASSERT(m->object, MA_OWNED); 2564 if (size == 0) /* handle degenerate case */ 2565 return; 2566 2567 /* 2568 * If the base is not DEV_BSIZE aligned and the valid 2569 * bit is clear, we have to zero out a portion of the 2570 * first block. 2571 */ 2572 if ((frag = base & ~(DEV_BSIZE - 1)) != base && 2573 (m->valid & (1 << (base >> DEV_BSHIFT))) == 0) 2574 pmap_zero_page_area(m, frag, base - frag); 2575 2576 /* 2577 * If the ending offset is not DEV_BSIZE aligned and the 2578 * valid bit is clear, we have to zero out a portion of 2579 * the last block. 2580 */ 2581 endoff = base + size; 2582 if ((frag = endoff & ~(DEV_BSIZE - 1)) != endoff && 2583 (m->valid & (1 << (endoff >> DEV_BSHIFT))) == 0) 2584 pmap_zero_page_area(m, endoff, 2585 DEV_BSIZE - (endoff & (DEV_BSIZE - 1))); 2586 2587 /* 2588 * Assert that no previously invalid block that is now being validated 2589 * is already dirty. 2590 */ 2591 KASSERT((~m->valid & vm_page_bits(base, size) & m->dirty) == 0, 2592 ("vm_page_set_valid_range: page %p is dirty", m)); 2593 2594 /* 2595 * Set valid bits inclusive of any overlap. 2596 */ 2597 m->valid |= vm_page_bits(base, size); 2598 } 2599 2600 /* 2601 * Clear the given bits from the specified page's dirty field. 2602 */ 2603 static __inline void 2604 vm_page_clear_dirty_mask(vm_page_t m, vm_page_bits_t pagebits) 2605 { 2606 uintptr_t addr; 2607 #if PAGE_SIZE < 16384 2608 int shift; 2609 #endif 2610 2611 /* 2612 * If the object is locked and the page is neither VPO_BUSY nor 2613 * PGA_WRITEABLE, then the page's dirty field cannot possibly be 2614 * set by a concurrent pmap operation. 2615 */ 2616 VM_OBJECT_LOCK_ASSERT(m->object, MA_OWNED); 2617 if ((m->oflags & VPO_BUSY) == 0 && (m->aflags & PGA_WRITEABLE) == 0) 2618 m->dirty &= ~pagebits; 2619 else { 2620 /* 2621 * The pmap layer can call vm_page_dirty() without 2622 * holding a distinguished lock. The combination of 2623 * the object's lock and an atomic operation suffice 2624 * to guarantee consistency of the page dirty field. 2625 * 2626 * For PAGE_SIZE == 32768 case, compiler already 2627 * properly aligns the dirty field, so no forcible 2628 * alignment is needed. Only require existence of 2629 * atomic_clear_64 when page size is 32768. 2630 */ 2631 addr = (uintptr_t)&m->dirty; 2632 #if PAGE_SIZE == 32768 2633 atomic_clear_64((uint64_t *)addr, pagebits); 2634 #elif PAGE_SIZE == 16384 2635 atomic_clear_32((uint32_t *)addr, pagebits); 2636 #else /* PAGE_SIZE <= 8192 */ 2637 /* 2638 * Use a trick to perform a 32-bit atomic on the 2639 * containing aligned word, to not depend on the existence 2640 * of atomic_clear_{8, 16}. 2641 */ 2642 shift = addr & (sizeof(uint32_t) - 1); 2643 #if BYTE_ORDER == BIG_ENDIAN 2644 shift = (sizeof(uint32_t) - sizeof(m->dirty) - shift) * NBBY; 2645 #else 2646 shift *= NBBY; 2647 #endif 2648 addr &= ~(sizeof(uint32_t) - 1); 2649 atomic_clear_32((uint32_t *)addr, pagebits << shift); 2650 #endif /* PAGE_SIZE */ 2651 } 2652 } 2653 2654 /* 2655 * vm_page_set_validclean: 2656 * 2657 * Sets portions of a page valid and clean. The arguments are expected 2658 * to be DEV_BSIZE aligned but if they aren't the bitmap is inclusive 2659 * of any partial chunks touched by the range. The invalid portion of 2660 * such chunks will be zero'd. 2661 * 2662 * This routine may not block. 2663 * 2664 * (base + size) must be less then or equal to PAGE_SIZE. 2665 */ 2666 void 2667 vm_page_set_validclean(vm_page_t m, int base, int size) 2668 { 2669 vm_page_bits_t oldvalid, pagebits; 2670 int endoff, frag; 2671 2672 VM_OBJECT_LOCK_ASSERT(m->object, MA_OWNED); 2673 if (size == 0) /* handle degenerate case */ 2674 return; 2675 2676 /* 2677 * If the base is not DEV_BSIZE aligned and the valid 2678 * bit is clear, we have to zero out a portion of the 2679 * first block. 2680 */ 2681 if ((frag = base & ~(DEV_BSIZE - 1)) != base && 2682 (m->valid & ((vm_page_bits_t)1 << (base >> DEV_BSHIFT))) == 0) 2683 pmap_zero_page_area(m, frag, base - frag); 2684 2685 /* 2686 * If the ending offset is not DEV_BSIZE aligned and the 2687 * valid bit is clear, we have to zero out a portion of 2688 * the last block. 2689 */ 2690 endoff = base + size; 2691 if ((frag = endoff & ~(DEV_BSIZE - 1)) != endoff && 2692 (m->valid & ((vm_page_bits_t)1 << (endoff >> DEV_BSHIFT))) == 0) 2693 pmap_zero_page_area(m, endoff, 2694 DEV_BSIZE - (endoff & (DEV_BSIZE - 1))); 2695 2696 /* 2697 * Set valid, clear dirty bits. If validating the entire 2698 * page we can safely clear the pmap modify bit. We also 2699 * use this opportunity to clear the VPO_NOSYNC flag. If a process 2700 * takes a write fault on a MAP_NOSYNC memory area the flag will 2701 * be set again. 2702 * 2703 * We set valid bits inclusive of any overlap, but we can only 2704 * clear dirty bits for DEV_BSIZE chunks that are fully within 2705 * the range. 2706 */ 2707 oldvalid = m->valid; 2708 pagebits = vm_page_bits(base, size); 2709 m->valid |= pagebits; 2710 #if 0 /* NOT YET */ 2711 if ((frag = base & (DEV_BSIZE - 1)) != 0) { 2712 frag = DEV_BSIZE - frag; 2713 base += frag; 2714 size -= frag; 2715 if (size < 0) 2716 size = 0; 2717 } 2718 pagebits = vm_page_bits(base, size & (DEV_BSIZE - 1)); 2719 #endif 2720 if (base == 0 && size == PAGE_SIZE) { 2721 /* 2722 * The page can only be modified within the pmap if it is 2723 * mapped, and it can only be mapped if it was previously 2724 * fully valid. 2725 */ 2726 if (oldvalid == VM_PAGE_BITS_ALL) 2727 /* 2728 * Perform the pmap_clear_modify() first. Otherwise, 2729 * a concurrent pmap operation, such as 2730 * pmap_protect(), could clear a modification in the 2731 * pmap and set the dirty field on the page before 2732 * pmap_clear_modify() had begun and after the dirty 2733 * field was cleared here. 2734 */ 2735 pmap_clear_modify(m); 2736 m->dirty = 0; 2737 m->oflags &= ~VPO_NOSYNC; 2738 } else if (oldvalid != VM_PAGE_BITS_ALL) 2739 m->dirty &= ~pagebits; 2740 else 2741 vm_page_clear_dirty_mask(m, pagebits); 2742 } 2743 2744 void 2745 vm_page_clear_dirty(vm_page_t m, int base, int size) 2746 { 2747 2748 vm_page_clear_dirty_mask(m, vm_page_bits(base, size)); 2749 } 2750 2751 /* 2752 * vm_page_set_invalid: 2753 * 2754 * Invalidates DEV_BSIZE'd chunks within a page. Both the 2755 * valid and dirty bits for the effected areas are cleared. 2756 * 2757 * May not block. 2758 */ 2759 void 2760 vm_page_set_invalid(vm_page_t m, int base, int size) 2761 { 2762 vm_page_bits_t bits; 2763 2764 VM_OBJECT_LOCK_ASSERT(m->object, MA_OWNED); 2765 KASSERT((m->oflags & VPO_BUSY) == 0, 2766 ("vm_page_set_invalid: page %p is busy", m)); 2767 bits = vm_page_bits(base, size); 2768 if (m->valid == VM_PAGE_BITS_ALL && bits != 0) 2769 pmap_remove_all(m); 2770 KASSERT(!pmap_page_is_mapped(m), 2771 ("vm_page_set_invalid: page %p is mapped", m)); 2772 m->valid &= ~bits; 2773 m->dirty &= ~bits; 2774 } 2775 2776 /* 2777 * vm_page_zero_invalid() 2778 * 2779 * The kernel assumes that the invalid portions of a page contain 2780 * garbage, but such pages can be mapped into memory by user code. 2781 * When this occurs, we must zero out the non-valid portions of the 2782 * page so user code sees what it expects. 2783 * 2784 * Pages are most often semi-valid when the end of a file is mapped 2785 * into memory and the file's size is not page aligned. 2786 */ 2787 void 2788 vm_page_zero_invalid(vm_page_t m, boolean_t setvalid) 2789 { 2790 int b; 2791 int i; 2792 2793 VM_OBJECT_LOCK_ASSERT(m->object, MA_OWNED); 2794 /* 2795 * Scan the valid bits looking for invalid sections that 2796 * must be zerod. Invalid sub-DEV_BSIZE'd areas ( where the 2797 * valid bit may be set ) have already been zerod by 2798 * vm_page_set_validclean(). 2799 */ 2800 for (b = i = 0; i <= PAGE_SIZE / DEV_BSIZE; ++i) { 2801 if (i == (PAGE_SIZE / DEV_BSIZE) || 2802 (m->valid & ((vm_page_bits_t)1 << i))) { 2803 if (i > b) { 2804 pmap_zero_page_area(m, 2805 b << DEV_BSHIFT, (i - b) << DEV_BSHIFT); 2806 } 2807 b = i + 1; 2808 } 2809 } 2810 2811 /* 2812 * setvalid is TRUE when we can safely set the zero'd areas 2813 * as being valid. We can do this if there are no cache consistancy 2814 * issues. e.g. it is ok to do with UFS, but not ok to do with NFS. 2815 */ 2816 if (setvalid) 2817 m->valid = VM_PAGE_BITS_ALL; 2818 } 2819 2820 /* 2821 * vm_page_is_valid: 2822 * 2823 * Is (partial) page valid? Note that the case where size == 0 2824 * will return FALSE in the degenerate case where the page is 2825 * entirely invalid, and TRUE otherwise. 2826 * 2827 * May not block. 2828 */ 2829 int 2830 vm_page_is_valid(vm_page_t m, int base, int size) 2831 { 2832 vm_page_bits_t bits; 2833 2834 VM_OBJECT_LOCK_ASSERT(m->object, MA_OWNED); 2835 bits = vm_page_bits(base, size); 2836 if (m->valid && ((m->valid & bits) == bits)) 2837 return 1; 2838 else 2839 return 0; 2840 } 2841 2842 /* 2843 * update dirty bits from pmap/mmu. May not block. 2844 */ 2845 void 2846 vm_page_test_dirty(vm_page_t m) 2847 { 2848 2849 VM_OBJECT_LOCK_ASSERT(m->object, MA_OWNED); 2850 if (m->dirty != VM_PAGE_BITS_ALL && pmap_is_modified(m)) 2851 vm_page_dirty(m); 2852 } 2853 2854 void 2855 vm_page_lock_KBI(vm_page_t m, const char *file, int line) 2856 { 2857 2858 mtx_lock_flags_(vm_page_lockptr(m), 0, file, line); 2859 } 2860 2861 void 2862 vm_page_unlock_KBI(vm_page_t m, const char *file, int line) 2863 { 2864 2865 mtx_unlock_flags_(vm_page_lockptr(m), 0, file, line); 2866 } 2867 2868 int 2869 vm_page_trylock_KBI(vm_page_t m, const char *file, int line) 2870 { 2871 2872 return (mtx_trylock_flags_(vm_page_lockptr(m), 0, file, line)); 2873 } 2874 2875 #if defined(INVARIANTS) || defined(INVARIANT_SUPPORT) 2876 void 2877 vm_page_lock_assert_KBI(vm_page_t m, int a, const char *file, int line) 2878 { 2879 2880 mtx_assert_(vm_page_lockptr(m), a, file, line); 2881 } 2882 #endif 2883 2884 int so_zerocp_fullpage = 0; 2885 2886 /* 2887 * Replace the given page with a copy. The copied page assumes 2888 * the portion of the given page's "wire_count" that is not the 2889 * responsibility of this copy-on-write mechanism. 2890 * 2891 * The object containing the given page must have a non-zero 2892 * paging-in-progress count and be locked. 2893 */ 2894 void 2895 vm_page_cowfault(vm_page_t m) 2896 { 2897 vm_page_t mnew; 2898 vm_object_t object; 2899 vm_pindex_t pindex; 2900 2901 mtx_assert(&vm_page_queue_mtx, MA_NOTOWNED); 2902 vm_page_lock_assert(m, MA_OWNED); 2903 object = m->object; 2904 VM_OBJECT_LOCK_ASSERT(object, MA_OWNED); 2905 KASSERT(object->paging_in_progress != 0, 2906 ("vm_page_cowfault: object %p's paging-in-progress count is zero.", 2907 object)); 2908 pindex = m->pindex; 2909 2910 retry_alloc: 2911 pmap_remove_all(m); 2912 vm_page_remove(m); 2913 mnew = vm_page_alloc(object, pindex, VM_ALLOC_NORMAL | VM_ALLOC_NOBUSY); 2914 if (mnew == NULL) { 2915 vm_page_insert(m, object, pindex); 2916 vm_page_unlock(m); 2917 VM_OBJECT_UNLOCK(object); 2918 VM_WAIT; 2919 VM_OBJECT_LOCK(object); 2920 if (m == vm_page_lookup(object, pindex)) { 2921 vm_page_lock(m); 2922 goto retry_alloc; 2923 } else { 2924 /* 2925 * Page disappeared during the wait. 2926 */ 2927 return; 2928 } 2929 } 2930 2931 if (m->cow == 0) { 2932 /* 2933 * check to see if we raced with an xmit complete when 2934 * waiting to allocate a page. If so, put things back 2935 * the way they were 2936 */ 2937 vm_page_unlock(m); 2938 vm_page_lock(mnew); 2939 vm_page_free(mnew); 2940 vm_page_unlock(mnew); 2941 vm_page_insert(m, object, pindex); 2942 } else { /* clear COW & copy page */ 2943 if (!so_zerocp_fullpage) 2944 pmap_copy_page(m, mnew); 2945 mnew->valid = VM_PAGE_BITS_ALL; 2946 vm_page_dirty(mnew); 2947 mnew->wire_count = m->wire_count - m->cow; 2948 m->wire_count = m->cow; 2949 vm_page_unlock(m); 2950 } 2951 } 2952 2953 void 2954 vm_page_cowclear(vm_page_t m) 2955 { 2956 2957 vm_page_lock_assert(m, MA_OWNED); 2958 if (m->cow) { 2959 m->cow--; 2960 /* 2961 * let vm_fault add back write permission lazily 2962 */ 2963 } 2964 /* 2965 * sf_buf_free() will free the page, so we needn't do it here 2966 */ 2967 } 2968 2969 int 2970 vm_page_cowsetup(vm_page_t m) 2971 { 2972 2973 vm_page_lock_assert(m, MA_OWNED); 2974 if ((m->flags & PG_FICTITIOUS) != 0 || 2975 (m->oflags & VPO_UNMANAGED) != 0 || 2976 m->cow == USHRT_MAX - 1 || !VM_OBJECT_TRYLOCK(m->object)) 2977 return (EBUSY); 2978 m->cow++; 2979 pmap_remove_write(m); 2980 VM_OBJECT_UNLOCK(m->object); 2981 return (0); 2982 } 2983 2984 #ifdef INVARIANTS 2985 void 2986 vm_page_object_lock_assert(vm_page_t m) 2987 { 2988 2989 /* 2990 * Certain of the page's fields may only be modified by the 2991 * holder of the containing object's lock or the setter of the 2992 * page's VPO_BUSY flag. Unfortunately, the setter of the 2993 * VPO_BUSY flag is not recorded, and thus cannot be checked 2994 * here. 2995 */ 2996 if (m->object != NULL && (m->oflags & VPO_BUSY) == 0) 2997 VM_OBJECT_LOCK_ASSERT(m->object, MA_OWNED); 2998 } 2999 #endif 3000 3001 #include "opt_ddb.h" 3002 #ifdef DDB 3003 #include <sys/kernel.h> 3004 3005 #include <ddb/ddb.h> 3006 3007 DB_SHOW_COMMAND(page, vm_page_print_page_info) 3008 { 3009 db_printf("cnt.v_free_count: %d\n", cnt.v_free_count); 3010 db_printf("cnt.v_cache_count: %d\n", cnt.v_cache_count); 3011 db_printf("cnt.v_inactive_count: %d\n", cnt.v_inactive_count); 3012 db_printf("cnt.v_active_count: %d\n", cnt.v_active_count); 3013 db_printf("cnt.v_wire_count: %d\n", cnt.v_wire_count); 3014 db_printf("cnt.v_free_reserved: %d\n", cnt.v_free_reserved); 3015 db_printf("cnt.v_free_min: %d\n", cnt.v_free_min); 3016 db_printf("cnt.v_free_target: %d\n", cnt.v_free_target); 3017 db_printf("cnt.v_cache_min: %d\n", cnt.v_cache_min); 3018 db_printf("cnt.v_inactive_target: %d\n", cnt.v_inactive_target); 3019 } 3020 3021 DB_SHOW_COMMAND(pageq, vm_page_print_pageq_info) 3022 { 3023 3024 db_printf("PQ_FREE:"); 3025 db_printf(" %d", cnt.v_free_count); 3026 db_printf("\n"); 3027 3028 db_printf("PQ_CACHE:"); 3029 db_printf(" %d", cnt.v_cache_count); 3030 db_printf("\n"); 3031 3032 db_printf("PQ_ACTIVE: %d, PQ_INACTIVE: %d\n", 3033 *vm_page_queues[PQ_ACTIVE].cnt, 3034 *vm_page_queues[PQ_INACTIVE].cnt); 3035 } 3036 #endif /* DDB */ 3037