vm_page.c revision 207577
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 * - a hash chain mutex is required when associating or disassociating 71 * a page from the VM PAGE CACHE hash table (vm_page_buckets), 72 * regardless of other mutexes or the busy state of a page. 73 * 74 * - either a hash chain mutex OR a busied page is required in order 75 * to modify the page flags. A hash chain mutex must be obtained in 76 * order to busy a page. A page's flags cannot be modified by a 77 * hash chain mutex if the page is marked busy. 78 * 79 * - The object memq mutex is held when inserting or removing 80 * pages from an object (vm_page_insert() or vm_page_remove()). This 81 * is different from the object's main mutex. 82 * 83 * Generally speaking, you have to be aware of side effects when running 84 * vm_page ops. A vm_page_lookup() will return with the hash chain 85 * locked, whether it was able to lookup the page or not. vm_page_free(), 86 * vm_page_cache(), vm_page_activate(), and a number of other routines 87 * will release the hash chain mutex for you. Intermediate manipulation 88 * routines such as vm_page_flag_set() expect the hash chain to be held 89 * on entry and the hash chain will remain held on return. 90 * 91 * pageq scanning can only occur with the pageq in question locked. 92 * We have a known bottleneck with the active queue, but the cache 93 * and free queues are actually arrays already. 94 */ 95 96/* 97 * Resident memory management module. 98 */ 99 100#include <sys/cdefs.h> 101__FBSDID("$FreeBSD: head/sys/vm/vm_page.c 207577 2010-05-03 17:55:32Z alc $"); 102 103#include "opt_vm.h" 104 105#include <sys/param.h> 106#include <sys/systm.h> 107#include <sys/lock.h> 108#include <sys/kernel.h> 109#include <sys/limits.h> 110#include <sys/malloc.h> 111#include <sys/mutex.h> 112#include <sys/proc.h> 113#include <sys/sysctl.h> 114#include <sys/vmmeter.h> 115#include <sys/vnode.h> 116 117#include <vm/vm.h> 118#include <vm/pmap.h> 119#include <vm/vm_param.h> 120#include <vm/vm_kern.h> 121#include <vm/vm_object.h> 122#include <vm/vm_page.h> 123#include <vm/vm_pageout.h> 124#include <vm/vm_pager.h> 125#include <vm/vm_phys.h> 126#include <vm/vm_reserv.h> 127#include <vm/vm_extern.h> 128#include <vm/uma.h> 129#include <vm/uma_int.h> 130 131#include <machine/md_var.h> 132 133#if defined(__amd64__) || defined (__i386__) 134extern struct sysctl_oid_list sysctl__vm_pmap_children; 135#else 136SYSCTL_NODE(_vm, OID_AUTO, pmap, CTLFLAG_RD, 0, "VM/pmap parameters"); 137#endif 138 139static uint64_t pmap_tryrelock_calls; 140SYSCTL_QUAD(_vm_pmap, OID_AUTO, tryrelock_calls, CTLFLAG_RD, 141 &pmap_tryrelock_calls, 0, "Number of tryrelock calls"); 142 143static int pmap_tryrelock_restart; 144SYSCTL_INT(_vm_pmap, OID_AUTO, tryrelock_restart, CTLFLAG_RD, 145 &pmap_tryrelock_restart, 0, "Number of tryrelock restarts"); 146 147static int pmap_tryrelock_race; 148SYSCTL_INT(_vm_pmap, OID_AUTO, tryrelock_race, CTLFLAG_RD, 149 &pmap_tryrelock_race, 0, "Number of tryrelock pmap race cases"); 150 151/* 152 * Associated with page of user-allocatable memory is a 153 * page structure. 154 */ 155 156struct vpgqueues vm_page_queues[PQ_COUNT]; 157struct vpglocks vm_page_queue_lock; 158struct vpglocks vm_page_queue_free_lock; 159 160struct vpglocks pa_lock[PA_LOCK_COUNT] __aligned(CACHE_LINE_SIZE); 161 162vm_page_t vm_page_array = 0; 163int vm_page_array_size = 0; 164long first_page = 0; 165int vm_page_zero_count = 0; 166 167static int boot_pages = UMA_BOOT_PAGES; 168TUNABLE_INT("vm.boot_pages", &boot_pages); 169SYSCTL_INT(_vm, OID_AUTO, boot_pages, CTLFLAG_RD, &boot_pages, 0, 170 "number of pages allocated for bootstrapping the VM system"); 171 172static void vm_page_enqueue(int queue, vm_page_t m); 173 174/* Make sure that u_long is at least 64 bits when PAGE_SIZE is 32K. */ 175#if PAGE_SIZE == 32768 176#ifdef CTASSERT 177CTASSERT(sizeof(u_long) >= 8); 178#endif 179#endif 180 181/* 182 * Try to acquire a physical address lock while a pmap is locked. If we 183 * fail to trylock we unlock and lock the pmap directly and cache the 184 * locked pa in *locked. The caller should then restart their loop in case 185 * the virtual to physical mapping has changed. 186 */ 187int 188vm_page_pa_tryrelock(pmap_t pmap, vm_paddr_t pa, vm_paddr_t *locked) 189{ 190 vm_paddr_t lockpa; 191 uint32_t gen_count; 192 193 gen_count = pmap->pm_gen_count; 194 atomic_add_long((volatile long *)&pmap_tryrelock_calls, 1); 195 lockpa = *locked; 196 *locked = pa; 197 if (lockpa) { 198 PA_LOCK_ASSERT(lockpa, MA_OWNED); 199 if (PA_LOCKPTR(pa) == PA_LOCKPTR(lockpa)) 200 return (0); 201 PA_UNLOCK(lockpa); 202 } 203 if (PA_TRYLOCK(pa)) 204 return (0); 205 PMAP_UNLOCK(pmap); 206 atomic_add_int((volatile int *)&pmap_tryrelock_restart, 1); 207 PA_LOCK(pa); 208 PMAP_LOCK(pmap); 209 210 if (pmap->pm_gen_count != gen_count + 1) { 211 pmap->pm_retries++; 212 atomic_add_int((volatile int *)&pmap_tryrelock_race, 1); 213 return (EAGAIN); 214 } 215 return (0); 216} 217 218/* 219 * vm_set_page_size: 220 * 221 * Sets the page size, perhaps based upon the memory 222 * size. Must be called before any use of page-size 223 * dependent functions. 224 */ 225void 226vm_set_page_size(void) 227{ 228 if (cnt.v_page_size == 0) 229 cnt.v_page_size = PAGE_SIZE; 230 if (((cnt.v_page_size - 1) & cnt.v_page_size) != 0) 231 panic("vm_set_page_size: page size not a power of two"); 232} 233 234/* 235 * vm_page_blacklist_lookup: 236 * 237 * See if a physical address in this page has been listed 238 * in the blacklist tunable. Entries in the tunable are 239 * separated by spaces or commas. If an invalid integer is 240 * encountered then the rest of the string is skipped. 241 */ 242static int 243vm_page_blacklist_lookup(char *list, vm_paddr_t pa) 244{ 245 vm_paddr_t bad; 246 char *cp, *pos; 247 248 for (pos = list; *pos != '\0'; pos = cp) { 249 bad = strtoq(pos, &cp, 0); 250 if (*cp != '\0') { 251 if (*cp == ' ' || *cp == ',') { 252 cp++; 253 if (cp == pos) 254 continue; 255 } else 256 break; 257 } 258 if (pa == trunc_page(bad)) 259 return (1); 260 } 261 return (0); 262} 263 264/* 265 * vm_page_startup: 266 * 267 * Initializes the resident memory module. 268 * 269 * Allocates memory for the page cells, and 270 * for the object/offset-to-page hash table headers. 271 * Each page cell is initialized and placed on the free list. 272 */ 273vm_offset_t 274vm_page_startup(vm_offset_t vaddr) 275{ 276 vm_offset_t mapped; 277 vm_paddr_t page_range; 278 vm_paddr_t new_end; 279 int i; 280 vm_paddr_t pa; 281 int nblocks; 282 vm_paddr_t last_pa; 283 char *list; 284 285 /* the biggest memory array is the second group of pages */ 286 vm_paddr_t end; 287 vm_paddr_t biggestsize; 288 vm_paddr_t low_water, high_water; 289 int biggestone; 290 291 biggestsize = 0; 292 biggestone = 0; 293 nblocks = 0; 294 vaddr = round_page(vaddr); 295 296 for (i = 0; phys_avail[i + 1]; i += 2) { 297 phys_avail[i] = round_page(phys_avail[i]); 298 phys_avail[i + 1] = trunc_page(phys_avail[i + 1]); 299 } 300 301 low_water = phys_avail[0]; 302 high_water = phys_avail[1]; 303 304 for (i = 0; phys_avail[i + 1]; i += 2) { 305 vm_paddr_t size = phys_avail[i + 1] - phys_avail[i]; 306 307 if (size > biggestsize) { 308 biggestone = i; 309 biggestsize = size; 310 } 311 if (phys_avail[i] < low_water) 312 low_water = phys_avail[i]; 313 if (phys_avail[i + 1] > high_water) 314 high_water = phys_avail[i + 1]; 315 ++nblocks; 316 } 317 318#ifdef XEN 319 low_water = 0; 320#endif 321 322 end = phys_avail[biggestone+1]; 323 324 /* 325 * Initialize the locks. 326 */ 327 mtx_init(&vm_page_queue_mtx, "vm page queue mutex", NULL, MTX_DEF | 328 MTX_RECURSE); 329 mtx_init(&vm_page_queue_free_mtx, "vm page queue free mutex", NULL, 330 MTX_DEF); 331 332 /* Setup page locks. */ 333 for (i = 0; i < PA_LOCK_COUNT; i++) 334 mtx_init(&pa_lock[i].data, "page lock", NULL, 335 MTX_DEF | MTX_RECURSE | MTX_DUPOK); 336 337 /* 338 * Initialize the queue headers for the hold queue, the active queue, 339 * and the inactive queue. 340 */ 341 for (i = 0; i < PQ_COUNT; i++) 342 TAILQ_INIT(&vm_page_queues[i].pl); 343 vm_page_queues[PQ_INACTIVE].cnt = &cnt.v_inactive_count; 344 vm_page_queues[PQ_ACTIVE].cnt = &cnt.v_active_count; 345 vm_page_queues[PQ_HOLD].cnt = &cnt.v_active_count; 346 347 /* 348 * Allocate memory for use when boot strapping the kernel memory 349 * allocator. 350 */ 351 new_end = end - (boot_pages * UMA_SLAB_SIZE); 352 new_end = trunc_page(new_end); 353 mapped = pmap_map(&vaddr, new_end, end, 354 VM_PROT_READ | VM_PROT_WRITE); 355 bzero((void *)mapped, end - new_end); 356 uma_startup((void *)mapped, boot_pages); 357 358#if defined(__amd64__) || defined(__i386__) || defined(__arm__) 359 /* 360 * Allocate a bitmap to indicate that a random physical page 361 * needs to be included in a minidump. 362 * 363 * The amd64 port needs this to indicate which direct map pages 364 * need to be dumped, via calls to dump_add_page()/dump_drop_page(). 365 * 366 * However, i386 still needs this workspace internally within the 367 * minidump code. In theory, they are not needed on i386, but are 368 * included should the sf_buf code decide to use them. 369 */ 370 page_range = phys_avail[(nblocks - 1) * 2 + 1] / PAGE_SIZE; 371 vm_page_dump_size = round_page(roundup2(page_range, NBBY) / NBBY); 372 new_end -= vm_page_dump_size; 373 vm_page_dump = (void *)(uintptr_t)pmap_map(&vaddr, new_end, 374 new_end + vm_page_dump_size, VM_PROT_READ | VM_PROT_WRITE); 375 bzero((void *)vm_page_dump, vm_page_dump_size); 376#endif 377 /* 378 * Compute the number of pages of memory that will be available for 379 * use (taking into account the overhead of a page structure per 380 * page). 381 */ 382 first_page = low_water / PAGE_SIZE; 383#ifdef VM_PHYSSEG_SPARSE 384 page_range = 0; 385 for (i = 0; phys_avail[i + 1] != 0; i += 2) 386 page_range += atop(phys_avail[i + 1] - phys_avail[i]); 387#elif defined(VM_PHYSSEG_DENSE) 388 page_range = high_water / PAGE_SIZE - first_page; 389#else 390#error "Either VM_PHYSSEG_DENSE or VM_PHYSSEG_SPARSE must be defined." 391#endif 392 end = new_end; 393 394 /* 395 * Reserve an unmapped guard page to trap access to vm_page_array[-1]. 396 */ 397 vaddr += PAGE_SIZE; 398 399 /* 400 * Initialize the mem entry structures now, and put them in the free 401 * queue. 402 */ 403 new_end = trunc_page(end - page_range * sizeof(struct vm_page)); 404 mapped = pmap_map(&vaddr, new_end, end, 405 VM_PROT_READ | VM_PROT_WRITE); 406 vm_page_array = (vm_page_t) mapped; 407#if VM_NRESERVLEVEL > 0 408 /* 409 * Allocate memory for the reservation management system's data 410 * structures. 411 */ 412 new_end = vm_reserv_startup(&vaddr, new_end, high_water); 413#endif 414#ifdef __amd64__ 415 /* 416 * pmap_map on amd64 comes out of the direct-map, not kvm like i386, 417 * so the pages must be tracked for a crashdump to include this data. 418 * This includes the vm_page_array and the early UMA bootstrap pages. 419 */ 420 for (pa = new_end; pa < phys_avail[biggestone + 1]; pa += PAGE_SIZE) 421 dump_add_page(pa); 422#endif 423 phys_avail[biggestone + 1] = new_end; 424 425 /* 426 * Clear all of the page structures 427 */ 428 bzero((caddr_t) vm_page_array, page_range * sizeof(struct vm_page)); 429 for (i = 0; i < page_range; i++) 430 vm_page_array[i].order = VM_NFREEORDER; 431 vm_page_array_size = page_range; 432 433 /* 434 * Initialize the physical memory allocator. 435 */ 436 vm_phys_init(); 437 438 /* 439 * Add every available physical page that is not blacklisted to 440 * the free lists. 441 */ 442 cnt.v_page_count = 0; 443 cnt.v_free_count = 0; 444 list = getenv("vm.blacklist"); 445 for (i = 0; phys_avail[i + 1] != 0; i += 2) { 446 pa = phys_avail[i]; 447 last_pa = phys_avail[i + 1]; 448 while (pa < last_pa) { 449 if (list != NULL && 450 vm_page_blacklist_lookup(list, pa)) 451 printf("Skipping page with pa 0x%jx\n", 452 (uintmax_t)pa); 453 else 454 vm_phys_add_page(pa); 455 pa += PAGE_SIZE; 456 } 457 } 458 freeenv(list); 459#if VM_NRESERVLEVEL > 0 460 /* 461 * Initialize the reservation management system. 462 */ 463 vm_reserv_init(); 464#endif 465 return (vaddr); 466} 467 468void 469vm_page_flag_set(vm_page_t m, unsigned short bits) 470{ 471 472 mtx_assert(&vm_page_queue_mtx, MA_OWNED); 473 m->flags |= bits; 474} 475 476void 477vm_page_flag_clear(vm_page_t m, unsigned short bits) 478{ 479 480 mtx_assert(&vm_page_queue_mtx, MA_OWNED); 481 m->flags &= ~bits; 482} 483 484void 485vm_page_busy(vm_page_t m) 486{ 487 488 VM_OBJECT_LOCK_ASSERT(m->object, MA_OWNED); 489 KASSERT((m->oflags & VPO_BUSY) == 0, 490 ("vm_page_busy: page already busy!!!")); 491 m->oflags |= VPO_BUSY; 492} 493 494/* 495 * vm_page_flash: 496 * 497 * wakeup anyone waiting for the page. 498 */ 499void 500vm_page_flash(vm_page_t m) 501{ 502 503 VM_OBJECT_LOCK_ASSERT(m->object, MA_OWNED); 504 if (m->oflags & VPO_WANTED) { 505 m->oflags &= ~VPO_WANTED; 506 wakeup(m); 507 } 508} 509 510/* 511 * vm_page_wakeup: 512 * 513 * clear the VPO_BUSY flag and wakeup anyone waiting for the 514 * page. 515 * 516 */ 517void 518vm_page_wakeup(vm_page_t m) 519{ 520 521 VM_OBJECT_LOCK_ASSERT(m->object, MA_OWNED); 522 KASSERT(m->oflags & VPO_BUSY, ("vm_page_wakeup: page not busy!!!")); 523 m->oflags &= ~VPO_BUSY; 524 vm_page_flash(m); 525} 526 527void 528vm_page_io_start(vm_page_t m) 529{ 530 531 VM_OBJECT_LOCK_ASSERT(m->object, MA_OWNED); 532 m->busy++; 533} 534 535void 536vm_page_io_finish(vm_page_t m) 537{ 538 539 VM_OBJECT_LOCK_ASSERT(m->object, MA_OWNED); 540 m->busy--; 541 if (m->busy == 0) 542 vm_page_flash(m); 543} 544 545/* 546 * Keep page from being freed by the page daemon 547 * much of the same effect as wiring, except much lower 548 * overhead and should be used only for *very* temporary 549 * holding ("wiring"). 550 */ 551void 552vm_page_hold(vm_page_t mem) 553{ 554 555 vm_page_lock_assert(mem, MA_OWNED); 556 mem->hold_count++; 557} 558 559void 560vm_page_unhold(vm_page_t mem) 561{ 562 563 vm_page_lock_assert(mem, MA_OWNED); 564 --mem->hold_count; 565 KASSERT(mem->hold_count >= 0, ("vm_page_unhold: hold count < 0!!!")); 566 if (mem->hold_count == 0 && VM_PAGE_INQUEUE2(mem, PQ_HOLD)) { 567 vm_page_lock_queues(); 568 vm_page_free_toq(mem); 569 vm_page_unlock_queues(); 570 } 571} 572 573/* 574 * vm_page_free: 575 * 576 * Free a page. 577 */ 578void 579vm_page_free(vm_page_t m) 580{ 581 582 m->flags &= ~PG_ZERO; 583 vm_page_free_toq(m); 584} 585 586/* 587 * vm_page_free_zero: 588 * 589 * Free a page to the zerod-pages queue 590 */ 591void 592vm_page_free_zero(vm_page_t m) 593{ 594 595 m->flags |= PG_ZERO; 596 vm_page_free_toq(m); 597} 598 599/* 600 * vm_page_sleep: 601 * 602 * Sleep and release the page and page queues locks. 603 * 604 * The object containing the given page must be locked. 605 */ 606void 607vm_page_sleep(vm_page_t m, const char *msg) 608{ 609 610 VM_OBJECT_LOCK_ASSERT(m->object, MA_OWNED); 611 if (mtx_owned(&vm_page_queue_mtx)) 612 vm_page_unlock_queues(); 613 if (mtx_owned(vm_page_lockptr(m))) 614 vm_page_unlock(m); 615 616 /* 617 * It's possible that while we sleep, the page will get 618 * unbusied and freed. If we are holding the object 619 * lock, we will assume we hold a reference to the object 620 * such that even if m->object changes, we can re-lock 621 * it. 622 */ 623 m->oflags |= VPO_WANTED; 624 msleep(m, VM_OBJECT_MTX(m->object), PVM, msg, 0); 625} 626 627/* 628 * vm_page_dirty: 629 * 630 * make page all dirty 631 */ 632void 633vm_page_dirty(vm_page_t m) 634{ 635 636 KASSERT((m->flags & PG_CACHED) == 0, 637 ("vm_page_dirty: page in cache!")); 638 KASSERT(!VM_PAGE_IS_FREE(m), 639 ("vm_page_dirty: page is free!")); 640 KASSERT(m->valid == VM_PAGE_BITS_ALL, 641 ("vm_page_dirty: page is invalid!")); 642 m->dirty = VM_PAGE_BITS_ALL; 643} 644 645/* 646 * vm_page_splay: 647 * 648 * Implements Sleator and Tarjan's top-down splay algorithm. Returns 649 * the vm_page containing the given pindex. If, however, that 650 * pindex is not found in the vm_object, returns a vm_page that is 651 * adjacent to the pindex, coming before or after it. 652 */ 653vm_page_t 654vm_page_splay(vm_pindex_t pindex, vm_page_t root) 655{ 656 struct vm_page dummy; 657 vm_page_t lefttreemax, righttreemin, y; 658 659 if (root == NULL) 660 return (root); 661 lefttreemax = righttreemin = &dummy; 662 for (;; root = y) { 663 if (pindex < root->pindex) { 664 if ((y = root->left) == NULL) 665 break; 666 if (pindex < y->pindex) { 667 /* Rotate right. */ 668 root->left = y->right; 669 y->right = root; 670 root = y; 671 if ((y = root->left) == NULL) 672 break; 673 } 674 /* Link into the new root's right tree. */ 675 righttreemin->left = root; 676 righttreemin = root; 677 } else if (pindex > root->pindex) { 678 if ((y = root->right) == NULL) 679 break; 680 if (pindex > y->pindex) { 681 /* Rotate left. */ 682 root->right = y->left; 683 y->left = root; 684 root = y; 685 if ((y = root->right) == NULL) 686 break; 687 } 688 /* Link into the new root's left tree. */ 689 lefttreemax->right = root; 690 lefttreemax = root; 691 } else 692 break; 693 } 694 /* Assemble the new root. */ 695 lefttreemax->right = root->left; 696 righttreemin->left = root->right; 697 root->left = dummy.right; 698 root->right = dummy.left; 699 return (root); 700} 701 702/* 703 * vm_page_insert: [ internal use only ] 704 * 705 * Inserts the given mem entry into the object and object list. 706 * 707 * The pagetables are not updated but will presumably fault the page 708 * in if necessary, or if a kernel page the caller will at some point 709 * enter the page into the kernel's pmap. We are not allowed to block 710 * here so we *can't* do this anyway. 711 * 712 * The object and page must be locked. 713 * This routine may not block. 714 */ 715void 716vm_page_insert(vm_page_t m, vm_object_t object, vm_pindex_t pindex) 717{ 718 vm_page_t root; 719 720 VM_OBJECT_LOCK_ASSERT(object, MA_OWNED); 721 if (m->object != NULL) 722 panic("vm_page_insert: page already inserted"); 723 724 /* 725 * Record the object/offset pair in this page 726 */ 727 m->object = object; 728 m->pindex = pindex; 729 730 /* 731 * Now link into the object's ordered list of backed pages. 732 */ 733 root = object->root; 734 if (root == NULL) { 735 m->left = NULL; 736 m->right = NULL; 737 TAILQ_INSERT_TAIL(&object->memq, m, listq); 738 } else { 739 root = vm_page_splay(pindex, root); 740 if (pindex < root->pindex) { 741 m->left = root->left; 742 m->right = root; 743 root->left = NULL; 744 TAILQ_INSERT_BEFORE(root, m, listq); 745 } else if (pindex == root->pindex) 746 panic("vm_page_insert: offset already allocated"); 747 else { 748 m->right = root->right; 749 m->left = root; 750 root->right = NULL; 751 TAILQ_INSERT_AFTER(&object->memq, root, m, listq); 752 } 753 } 754 object->root = m; 755 object->generation++; 756 757 /* 758 * show that the object has one more resident page. 759 */ 760 object->resident_page_count++; 761 /* 762 * Hold the vnode until the last page is released. 763 */ 764 if (object->resident_page_count == 1 && object->type == OBJT_VNODE) 765 vhold((struct vnode *)object->handle); 766 767 /* 768 * Since we are inserting a new and possibly dirty page, 769 * update the object's OBJ_MIGHTBEDIRTY flag. 770 */ 771 if (m->flags & PG_WRITEABLE) 772 vm_object_set_writeable_dirty(object); 773} 774 775/* 776 * vm_page_remove: 777 * NOTE: used by device pager as well -wfj 778 * 779 * Removes the given mem entry from the object/offset-page 780 * table and the object page list, but do not invalidate/terminate 781 * the backing store. 782 * 783 * The object and page must be locked. 784 * The underlying pmap entry (if any) is NOT removed here. 785 * This routine may not block. 786 */ 787void 788vm_page_remove(vm_page_t m) 789{ 790 vm_object_t object; 791 vm_page_t root; 792 793 if ((m->flags & PG_UNMANAGED) == 0) 794 mtx_assert(&vm_page_queue_mtx, MA_OWNED); 795 if ((object = m->object) == NULL) 796 return; 797 VM_OBJECT_LOCK_ASSERT(object, MA_OWNED); 798 if (m->oflags & VPO_BUSY) { 799 m->oflags &= ~VPO_BUSY; 800 vm_page_flash(m); 801 } 802 803 /* 804 * Now remove from the object's list of backed pages. 805 */ 806 if (m != object->root) 807 vm_page_splay(m->pindex, object->root); 808 if (m->left == NULL) 809 root = m->right; 810 else { 811 root = vm_page_splay(m->pindex, m->left); 812 root->right = m->right; 813 } 814 object->root = root; 815 TAILQ_REMOVE(&object->memq, m, listq); 816 817 /* 818 * And show that the object has one fewer resident page. 819 */ 820 object->resident_page_count--; 821 object->generation++; 822 /* 823 * The vnode may now be recycled. 824 */ 825 if (object->resident_page_count == 0 && object->type == OBJT_VNODE) 826 vdrop((struct vnode *)object->handle); 827 828 m->object = NULL; 829} 830 831/* 832 * vm_page_lookup: 833 * 834 * Returns the page associated with the object/offset 835 * pair specified; if none is found, NULL is returned. 836 * 837 * The object must be locked. 838 * This routine may not block. 839 * This is a critical path routine 840 */ 841vm_page_t 842vm_page_lookup(vm_object_t object, vm_pindex_t pindex) 843{ 844 vm_page_t m; 845 846 VM_OBJECT_LOCK_ASSERT(object, MA_OWNED); 847 if ((m = object->root) != NULL && m->pindex != pindex) { 848 m = vm_page_splay(pindex, m); 849 if ((object->root = m)->pindex != pindex) 850 m = NULL; 851 } 852 return (m); 853} 854 855/* 856 * vm_page_rename: 857 * 858 * Move the given memory entry from its 859 * current object to the specified target object/offset. 860 * 861 * The object must be locked. 862 * This routine may not block. 863 * 864 * Note: swap associated with the page must be invalidated by the move. We 865 * have to do this for several reasons: (1) we aren't freeing the 866 * page, (2) we are dirtying the page, (3) the VM system is probably 867 * moving the page from object A to B, and will then later move 868 * the backing store from A to B and we can't have a conflict. 869 * 870 * Note: we *always* dirty the page. It is necessary both for the 871 * fact that we moved it, and because we may be invalidating 872 * swap. If the page is on the cache, we have to deactivate it 873 * or vm_page_dirty() will panic. Dirty pages are not allowed 874 * on the cache. 875 */ 876void 877vm_page_rename(vm_page_t m, vm_object_t new_object, vm_pindex_t new_pindex) 878{ 879 880 vm_page_remove(m); 881 vm_page_insert(m, new_object, new_pindex); 882 vm_page_dirty(m); 883} 884 885/* 886 * Convert all of the given object's cached pages that have a 887 * pindex within the given range into free pages. If the value 888 * zero is given for "end", then the range's upper bound is 889 * infinity. If the given object is backed by a vnode and it 890 * transitions from having one or more cached pages to none, the 891 * vnode's hold count is reduced. 892 */ 893void 894vm_page_cache_free(vm_object_t object, vm_pindex_t start, vm_pindex_t end) 895{ 896 vm_page_t m, m_next; 897 boolean_t empty; 898 899 mtx_lock(&vm_page_queue_free_mtx); 900 if (__predict_false(object->cache == NULL)) { 901 mtx_unlock(&vm_page_queue_free_mtx); 902 return; 903 } 904 m = object->cache = vm_page_splay(start, object->cache); 905 if (m->pindex < start) { 906 if (m->right == NULL) 907 m = NULL; 908 else { 909 m_next = vm_page_splay(start, m->right); 910 m_next->left = m; 911 m->right = NULL; 912 m = object->cache = m_next; 913 } 914 } 915 916 /* 917 * At this point, "m" is either (1) a reference to the page 918 * with the least pindex that is greater than or equal to 919 * "start" or (2) NULL. 920 */ 921 for (; m != NULL && (m->pindex < end || end == 0); m = m_next) { 922 /* 923 * Find "m"'s successor and remove "m" from the 924 * object's cache. 925 */ 926 if (m->right == NULL) { 927 object->cache = m->left; 928 m_next = NULL; 929 } else { 930 m_next = vm_page_splay(start, m->right); 931 m_next->left = m->left; 932 object->cache = m_next; 933 } 934 /* Convert "m" to a free page. */ 935 m->object = NULL; 936 m->valid = 0; 937 /* Clear PG_CACHED and set PG_FREE. */ 938 m->flags ^= PG_CACHED | PG_FREE; 939 KASSERT((m->flags & (PG_CACHED | PG_FREE)) == PG_FREE, 940 ("vm_page_cache_free: page %p has inconsistent flags", m)); 941 cnt.v_cache_count--; 942 cnt.v_free_count++; 943 } 944 empty = object->cache == NULL; 945 mtx_unlock(&vm_page_queue_free_mtx); 946 if (object->type == OBJT_VNODE && empty) 947 vdrop(object->handle); 948} 949 950/* 951 * Returns the cached page that is associated with the given 952 * object and offset. If, however, none exists, returns NULL. 953 * 954 * The free page queue must be locked. 955 */ 956static inline vm_page_t 957vm_page_cache_lookup(vm_object_t object, vm_pindex_t pindex) 958{ 959 vm_page_t m; 960 961 mtx_assert(&vm_page_queue_free_mtx, MA_OWNED); 962 if ((m = object->cache) != NULL && m->pindex != pindex) { 963 m = vm_page_splay(pindex, m); 964 if ((object->cache = m)->pindex != pindex) 965 m = NULL; 966 } 967 return (m); 968} 969 970/* 971 * Remove the given cached page from its containing object's 972 * collection of cached pages. 973 * 974 * The free page queue must be locked. 975 */ 976void 977vm_page_cache_remove(vm_page_t m) 978{ 979 vm_object_t object; 980 vm_page_t root; 981 982 mtx_assert(&vm_page_queue_free_mtx, MA_OWNED); 983 KASSERT((m->flags & PG_CACHED) != 0, 984 ("vm_page_cache_remove: page %p is not cached", m)); 985 object = m->object; 986 if (m != object->cache) { 987 root = vm_page_splay(m->pindex, object->cache); 988 KASSERT(root == m, 989 ("vm_page_cache_remove: page %p is not cached in object %p", 990 m, object)); 991 } 992 if (m->left == NULL) 993 root = m->right; 994 else if (m->right == NULL) 995 root = m->left; 996 else { 997 root = vm_page_splay(m->pindex, m->left); 998 root->right = m->right; 999 } 1000 object->cache = root; 1001 m->object = NULL; 1002 cnt.v_cache_count--; 1003} 1004 1005/* 1006 * Transfer all of the cached pages with offset greater than or 1007 * equal to 'offidxstart' from the original object's cache to the 1008 * new object's cache. However, any cached pages with offset 1009 * greater than or equal to the new object's size are kept in the 1010 * original object. Initially, the new object's cache must be 1011 * empty. Offset 'offidxstart' in the original object must 1012 * correspond to offset zero in the new object. 1013 * 1014 * The new object must be locked. 1015 */ 1016void 1017vm_page_cache_transfer(vm_object_t orig_object, vm_pindex_t offidxstart, 1018 vm_object_t new_object) 1019{ 1020 vm_page_t m, m_next; 1021 1022 /* 1023 * Insertion into an object's collection of cached pages 1024 * requires the object to be locked. In contrast, removal does 1025 * not. 1026 */ 1027 VM_OBJECT_LOCK_ASSERT(new_object, MA_OWNED); 1028 KASSERT(new_object->cache == NULL, 1029 ("vm_page_cache_transfer: object %p has cached pages", 1030 new_object)); 1031 mtx_lock(&vm_page_queue_free_mtx); 1032 if ((m = orig_object->cache) != NULL) { 1033 /* 1034 * Transfer all of the pages with offset greater than or 1035 * equal to 'offidxstart' from the original object's 1036 * cache to the new object's cache. 1037 */ 1038 m = vm_page_splay(offidxstart, m); 1039 if (m->pindex < offidxstart) { 1040 orig_object->cache = m; 1041 new_object->cache = m->right; 1042 m->right = NULL; 1043 } else { 1044 orig_object->cache = m->left; 1045 new_object->cache = m; 1046 m->left = NULL; 1047 } 1048 while ((m = new_object->cache) != NULL) { 1049 if ((m->pindex - offidxstart) >= new_object->size) { 1050 /* 1051 * Return all of the cached pages with 1052 * offset greater than or equal to the 1053 * new object's size to the original 1054 * object's cache. 1055 */ 1056 new_object->cache = m->left; 1057 m->left = orig_object->cache; 1058 orig_object->cache = m; 1059 break; 1060 } 1061 m_next = vm_page_splay(m->pindex, m->right); 1062 /* Update the page's object and offset. */ 1063 m->object = new_object; 1064 m->pindex -= offidxstart; 1065 if (m_next == NULL) 1066 break; 1067 m->right = NULL; 1068 m_next->left = m; 1069 new_object->cache = m_next; 1070 } 1071 KASSERT(new_object->cache == NULL || 1072 new_object->type == OBJT_SWAP, 1073 ("vm_page_cache_transfer: object %p's type is incompatible" 1074 " with cached pages", new_object)); 1075 } 1076 mtx_unlock(&vm_page_queue_free_mtx); 1077} 1078 1079/* 1080 * vm_page_alloc: 1081 * 1082 * Allocate and return a memory cell associated 1083 * with this VM object/offset pair. 1084 * 1085 * page_req classes: 1086 * VM_ALLOC_NORMAL normal process request 1087 * VM_ALLOC_SYSTEM system *really* needs a page 1088 * VM_ALLOC_INTERRUPT interrupt time request 1089 * VM_ALLOC_ZERO zero page 1090 * VM_ALLOC_WIRED wire the allocated page 1091 * VM_ALLOC_NOOBJ page is not associated with a vm object 1092 * VM_ALLOC_NOBUSY do not set the page busy 1093 * VM_ALLOC_IFNOTCACHED return NULL, do not reactivate if the page 1094 * is cached 1095 * 1096 * This routine may not sleep. 1097 */ 1098vm_page_t 1099vm_page_alloc(vm_object_t object, vm_pindex_t pindex, int req) 1100{ 1101 struct vnode *vp = NULL; 1102 vm_object_t m_object; 1103 vm_page_t m; 1104 int flags, page_req; 1105 1106 page_req = req & VM_ALLOC_CLASS_MASK; 1107 KASSERT(curthread->td_intr_nesting_level == 0 || 1108 page_req == VM_ALLOC_INTERRUPT, 1109 ("vm_page_alloc(NORMAL|SYSTEM) in interrupt context")); 1110 1111 if ((req & VM_ALLOC_NOOBJ) == 0) { 1112 KASSERT(object != NULL, 1113 ("vm_page_alloc: NULL object.")); 1114 VM_OBJECT_LOCK_ASSERT(object, MA_OWNED); 1115 } 1116 1117 /* 1118 * The pager is allowed to eat deeper into the free page list. 1119 */ 1120 if ((curproc == pageproc) && (page_req != VM_ALLOC_INTERRUPT)) { 1121 page_req = VM_ALLOC_SYSTEM; 1122 }; 1123 1124 mtx_lock(&vm_page_queue_free_mtx); 1125 if (cnt.v_free_count + cnt.v_cache_count > cnt.v_free_reserved || 1126 (page_req == VM_ALLOC_SYSTEM && 1127 cnt.v_free_count + cnt.v_cache_count > cnt.v_interrupt_free_min) || 1128 (page_req == VM_ALLOC_INTERRUPT && 1129 cnt.v_free_count + cnt.v_cache_count > 0)) { 1130 /* 1131 * Allocate from the free queue if the number of free pages 1132 * exceeds the minimum for the request class. 1133 */ 1134 if (object != NULL && 1135 (m = vm_page_cache_lookup(object, pindex)) != NULL) { 1136 if ((req & VM_ALLOC_IFNOTCACHED) != 0) { 1137 mtx_unlock(&vm_page_queue_free_mtx); 1138 return (NULL); 1139 } 1140 if (vm_phys_unfree_page(m)) 1141 vm_phys_set_pool(VM_FREEPOOL_DEFAULT, m, 0); 1142#if VM_NRESERVLEVEL > 0 1143 else if (!vm_reserv_reactivate_page(m)) 1144#else 1145 else 1146#endif 1147 panic("vm_page_alloc: cache page %p is missing" 1148 " from the free queue", m); 1149 } else if ((req & VM_ALLOC_IFCACHED) != 0) { 1150 mtx_unlock(&vm_page_queue_free_mtx); 1151 return (NULL); 1152#if VM_NRESERVLEVEL > 0 1153 } else if (object == NULL || object->type == OBJT_DEVICE || 1154 object->type == OBJT_SG || 1155 (object->flags & OBJ_COLORED) == 0 || 1156 (m = vm_reserv_alloc_page(object, pindex)) == NULL) { 1157#else 1158 } else { 1159#endif 1160 m = vm_phys_alloc_pages(object != NULL ? 1161 VM_FREEPOOL_DEFAULT : VM_FREEPOOL_DIRECT, 0); 1162#if VM_NRESERVLEVEL > 0 1163 if (m == NULL && vm_reserv_reclaim_inactive()) { 1164 m = vm_phys_alloc_pages(object != NULL ? 1165 VM_FREEPOOL_DEFAULT : VM_FREEPOOL_DIRECT, 1166 0); 1167 } 1168#endif 1169 } 1170 } else { 1171 /* 1172 * Not allocatable, give up. 1173 */ 1174 mtx_unlock(&vm_page_queue_free_mtx); 1175 atomic_add_int(&vm_pageout_deficit, 1); 1176 pagedaemon_wakeup(); 1177 return (NULL); 1178 } 1179 1180 /* 1181 * At this point we had better have found a good page. 1182 */ 1183 1184 KASSERT(m != NULL, ("vm_page_alloc: missing page")); 1185 KASSERT(m->queue == PQ_NONE, 1186 ("vm_page_alloc: page %p has unexpected queue %d", m, m->queue)); 1187 KASSERT(m->wire_count == 0, ("vm_page_alloc: page %p is wired", m)); 1188 KASSERT(m->hold_count == 0, ("vm_page_alloc: page %p is held", m)); 1189 KASSERT(m->busy == 0, ("vm_page_alloc: page %p is busy", m)); 1190 KASSERT(m->dirty == 0, ("vm_page_alloc: page %p is dirty", m)); 1191 KASSERT(pmap_page_get_memattr(m) == VM_MEMATTR_DEFAULT, 1192 ("vm_page_alloc: page %p has unexpected memattr %d", m, 1193 pmap_page_get_memattr(m))); 1194 if ((m->flags & PG_CACHED) != 0) { 1195 KASSERT(m->valid != 0, 1196 ("vm_page_alloc: cached page %p is invalid", m)); 1197 if (m->object == object && m->pindex == pindex) 1198 cnt.v_reactivated++; 1199 else 1200 m->valid = 0; 1201 m_object = m->object; 1202 vm_page_cache_remove(m); 1203 if (m_object->type == OBJT_VNODE && m_object->cache == NULL) 1204 vp = m_object->handle; 1205 } else { 1206 KASSERT(VM_PAGE_IS_FREE(m), 1207 ("vm_page_alloc: page %p is not free", m)); 1208 KASSERT(m->valid == 0, 1209 ("vm_page_alloc: free page %p is valid", m)); 1210 cnt.v_free_count--; 1211 } 1212 1213 /* 1214 * Initialize structure. Only the PG_ZERO flag is inherited. 1215 */ 1216 flags = 0; 1217 if (m->flags & PG_ZERO) { 1218 vm_page_zero_count--; 1219 if (req & VM_ALLOC_ZERO) 1220 flags = PG_ZERO; 1221 } 1222 if (object == NULL || object->type == OBJT_PHYS) 1223 flags |= PG_UNMANAGED; 1224 m->flags = flags; 1225 if (req & (VM_ALLOC_NOBUSY | VM_ALLOC_NOOBJ)) 1226 m->oflags = 0; 1227 else 1228 m->oflags = VPO_BUSY; 1229 if (req & VM_ALLOC_WIRED) { 1230 atomic_add_int(&cnt.v_wire_count, 1); 1231 m->wire_count = 1; 1232 } 1233 m->act_count = 0; 1234 mtx_unlock(&vm_page_queue_free_mtx); 1235 1236 if (object != NULL) { 1237 /* Ignore device objects; the pager sets "memattr" for them. */ 1238 if (object->memattr != VM_MEMATTR_DEFAULT && 1239 object->type != OBJT_DEVICE && object->type != OBJT_SG) 1240 pmap_page_set_memattr(m, object->memattr); 1241 vm_page_insert(m, object, pindex); 1242 } else 1243 m->pindex = pindex; 1244 1245 /* 1246 * The following call to vdrop() must come after the above call 1247 * to vm_page_insert() in case both affect the same object and 1248 * vnode. Otherwise, the affected vnode's hold count could 1249 * temporarily become zero. 1250 */ 1251 if (vp != NULL) 1252 vdrop(vp); 1253 1254 /* 1255 * Don't wakeup too often - wakeup the pageout daemon when 1256 * we would be nearly out of memory. 1257 */ 1258 if (vm_paging_needed()) 1259 pagedaemon_wakeup(); 1260 1261 return (m); 1262} 1263 1264/* 1265 * vm_wait: (also see VM_WAIT macro) 1266 * 1267 * Block until free pages are available for allocation 1268 * - Called in various places before memory allocations. 1269 */ 1270void 1271vm_wait(void) 1272{ 1273 1274 mtx_lock(&vm_page_queue_free_mtx); 1275 if (curproc == pageproc) { 1276 vm_pageout_pages_needed = 1; 1277 msleep(&vm_pageout_pages_needed, &vm_page_queue_free_mtx, 1278 PDROP | PSWP, "VMWait", 0); 1279 } else { 1280 if (!vm_pages_needed) { 1281 vm_pages_needed = 1; 1282 wakeup(&vm_pages_needed); 1283 } 1284 msleep(&cnt.v_free_count, &vm_page_queue_free_mtx, PDROP | PVM, 1285 "vmwait", 0); 1286 } 1287} 1288 1289/* 1290 * vm_waitpfault: (also see VM_WAITPFAULT macro) 1291 * 1292 * Block until free pages are available for allocation 1293 * - Called only in vm_fault so that processes page faulting 1294 * can be easily tracked. 1295 * - Sleeps at a lower priority than vm_wait() so that vm_wait()ing 1296 * processes will be able to grab memory first. Do not change 1297 * this balance without careful testing first. 1298 */ 1299void 1300vm_waitpfault(void) 1301{ 1302 1303 mtx_lock(&vm_page_queue_free_mtx); 1304 if (!vm_pages_needed) { 1305 vm_pages_needed = 1; 1306 wakeup(&vm_pages_needed); 1307 } 1308 msleep(&cnt.v_free_count, &vm_page_queue_free_mtx, PDROP | PUSER, 1309 "pfault", 0); 1310} 1311 1312/* 1313 * vm_page_requeue: 1314 * 1315 * If the given page is contained within a page queue, move it to the tail 1316 * of that queue. 1317 * 1318 * The page queues must be locked. 1319 */ 1320void 1321vm_page_requeue(vm_page_t m) 1322{ 1323 int queue = VM_PAGE_GETQUEUE(m); 1324 struct vpgqueues *vpq; 1325 1326 if (queue != PQ_NONE) { 1327 vpq = &vm_page_queues[queue]; 1328 TAILQ_REMOVE(&vpq->pl, m, pageq); 1329 TAILQ_INSERT_TAIL(&vpq->pl, m, pageq); 1330 } 1331} 1332 1333/* 1334 * vm_pageq_remove: 1335 * 1336 * Remove a page from its queue. 1337 * 1338 * The queue containing the given page must be locked. 1339 * This routine may not block. 1340 */ 1341void 1342vm_pageq_remove(vm_page_t m) 1343{ 1344 int queue = VM_PAGE_GETQUEUE(m); 1345 struct vpgqueues *pq; 1346 1347 if (queue != PQ_NONE) { 1348 VM_PAGE_SETQUEUE2(m, PQ_NONE); 1349 pq = &vm_page_queues[queue]; 1350 TAILQ_REMOVE(&pq->pl, m, pageq); 1351 (*pq->cnt)--; 1352 } 1353} 1354 1355/* 1356 * vm_page_enqueue: 1357 * 1358 * Add the given page to the specified queue. 1359 * 1360 * The page queues must be locked. 1361 */ 1362static void 1363vm_page_enqueue(int queue, vm_page_t m) 1364{ 1365 struct vpgqueues *vpq; 1366 1367 vpq = &vm_page_queues[queue]; 1368 VM_PAGE_SETQUEUE2(m, queue); 1369 TAILQ_INSERT_TAIL(&vpq->pl, m, pageq); 1370 ++*vpq->cnt; 1371} 1372 1373/* 1374 * vm_page_activate: 1375 * 1376 * Put the specified page on the active list (if appropriate). 1377 * Ensure that act_count is at least ACT_INIT but do not otherwise 1378 * mess with it. 1379 * 1380 * The page queues must be locked. 1381 * This routine may not block. 1382 */ 1383void 1384vm_page_activate(vm_page_t m) 1385{ 1386 1387 mtx_assert(&vm_page_queue_mtx, MA_OWNED); 1388 if (VM_PAGE_GETKNOWNQUEUE2(m) != PQ_ACTIVE) { 1389 vm_pageq_remove(m); 1390 if (m->wire_count == 0 && (m->flags & PG_UNMANAGED) == 0) { 1391 if (m->act_count < ACT_INIT) 1392 m->act_count = ACT_INIT; 1393 vm_page_enqueue(PQ_ACTIVE, m); 1394 } 1395 } else { 1396 if (m->act_count < ACT_INIT) 1397 m->act_count = ACT_INIT; 1398 } 1399} 1400 1401/* 1402 * vm_page_free_wakeup: 1403 * 1404 * Helper routine for vm_page_free_toq() and vm_page_cache(). This 1405 * routine is called when a page has been added to the cache or free 1406 * queues. 1407 * 1408 * The page queues must be locked. 1409 * This routine may not block. 1410 */ 1411static inline void 1412vm_page_free_wakeup(void) 1413{ 1414 1415 mtx_assert(&vm_page_queue_free_mtx, MA_OWNED); 1416 /* 1417 * if pageout daemon needs pages, then tell it that there are 1418 * some free. 1419 */ 1420 if (vm_pageout_pages_needed && 1421 cnt.v_cache_count + cnt.v_free_count >= cnt.v_pageout_free_min) { 1422 wakeup(&vm_pageout_pages_needed); 1423 vm_pageout_pages_needed = 0; 1424 } 1425 /* 1426 * wakeup processes that are waiting on memory if we hit a 1427 * high water mark. And wakeup scheduler process if we have 1428 * lots of memory. this process will swapin processes. 1429 */ 1430 if (vm_pages_needed && !vm_page_count_min()) { 1431 vm_pages_needed = 0; 1432 wakeup(&cnt.v_free_count); 1433 } 1434} 1435 1436/* 1437 * vm_page_free_toq: 1438 * 1439 * Returns the given page to the free list, 1440 * disassociating it with any VM object. 1441 * 1442 * Object and page must be locked prior to entry. 1443 * This routine may not block. 1444 */ 1445 1446void 1447vm_page_free_toq(vm_page_t m) 1448{ 1449 1450 if (VM_PAGE_GETQUEUE(m) != PQ_NONE) 1451 mtx_assert(&vm_page_queue_mtx, MA_OWNED); 1452 KASSERT(!pmap_page_is_mapped(m), 1453 ("vm_page_free_toq: freeing mapped page %p", m)); 1454 PCPU_INC(cnt.v_tfree); 1455 1456 if (m->busy || VM_PAGE_IS_FREE(m)) { 1457 printf( 1458 "vm_page_free: pindex(%lu), busy(%d), VPO_BUSY(%d), hold(%d)\n", 1459 (u_long)m->pindex, m->busy, (m->oflags & VPO_BUSY) ? 1 : 0, 1460 m->hold_count); 1461 if (VM_PAGE_IS_FREE(m)) 1462 panic("vm_page_free: freeing free page"); 1463 else 1464 panic("vm_page_free: freeing busy page"); 1465 } 1466 1467 /* 1468 * unqueue, then remove page. Note that we cannot destroy 1469 * the page here because we do not want to call the pager's 1470 * callback routine until after we've put the page on the 1471 * appropriate free queue. 1472 */ 1473 vm_pageq_remove(m); 1474 vm_page_remove(m); 1475 1476 /* 1477 * If fictitious remove object association and 1478 * return, otherwise delay object association removal. 1479 */ 1480 if ((m->flags & PG_FICTITIOUS) != 0) { 1481 return; 1482 } 1483 1484 m->valid = 0; 1485 vm_page_undirty(m); 1486 1487 if (m->wire_count != 0) { 1488 if (m->wire_count > 1) { 1489 panic("vm_page_free: invalid wire count (%d), pindex: 0x%lx", 1490 m->wire_count, (long)m->pindex); 1491 } 1492 panic("vm_page_free: freeing wired page"); 1493 } 1494 if (m->hold_count != 0) { 1495 vm_page_lock_assert(m, MA_OWNED); 1496 m->flags &= ~PG_ZERO; 1497 vm_page_enqueue(PQ_HOLD, m); 1498 } else { 1499 /* 1500 * Restore the default memory attribute to the page. 1501 */ 1502 if (pmap_page_get_memattr(m) != VM_MEMATTR_DEFAULT) 1503 pmap_page_set_memattr(m, VM_MEMATTR_DEFAULT); 1504 1505 /* 1506 * Insert the page into the physical memory allocator's 1507 * cache/free page queues. 1508 */ 1509 mtx_lock(&vm_page_queue_free_mtx); 1510 m->flags |= PG_FREE; 1511 cnt.v_free_count++; 1512#if VM_NRESERVLEVEL > 0 1513 if (!vm_reserv_free_page(m)) 1514#else 1515 if (TRUE) 1516#endif 1517 vm_phys_free_pages(m, 0); 1518 if ((m->flags & PG_ZERO) != 0) 1519 ++vm_page_zero_count; 1520 else 1521 vm_page_zero_idle_wakeup(); 1522 vm_page_free_wakeup(); 1523 mtx_unlock(&vm_page_queue_free_mtx); 1524 } 1525} 1526 1527/* 1528 * vm_page_wire: 1529 * 1530 * Mark this page as wired down by yet 1531 * another map, removing it from paging queues 1532 * as necessary. 1533 * 1534 * The page queues must be locked. 1535 * This routine may not block. 1536 */ 1537void 1538vm_page_wire(vm_page_t m) 1539{ 1540 1541 /* 1542 * Only bump the wire statistics if the page is not already wired, 1543 * and only unqueue the page if it is on some queue (if it is unmanaged 1544 * it is already off the queues). 1545 */ 1546 mtx_assert(&vm_page_queue_mtx, MA_OWNED); 1547 vm_page_lock_assert(m, MA_OWNED); 1548 if (m->flags & PG_FICTITIOUS) 1549 return; 1550 if (m->wire_count == 0) { 1551 if ((m->flags & PG_UNMANAGED) == 0) 1552 vm_pageq_remove(m); 1553 atomic_add_int(&cnt.v_wire_count, 1); 1554 } 1555 m->wire_count++; 1556 KASSERT(m->wire_count != 0, ("vm_page_wire: wire_count overflow m=%p", m)); 1557} 1558 1559/* 1560 * vm_page_unwire: 1561 * 1562 * Release one wiring of this page, potentially 1563 * enabling it to be paged again. 1564 * 1565 * Many pages placed on the inactive queue should actually go 1566 * into the cache, but it is difficult to figure out which. What 1567 * we do instead, if the inactive target is well met, is to put 1568 * clean pages at the head of the inactive queue instead of the tail. 1569 * This will cause them to be moved to the cache more quickly and 1570 * if not actively re-referenced, freed more quickly. If we just 1571 * stick these pages at the end of the inactive queue, heavy filesystem 1572 * meta-data accesses can cause an unnecessary paging load on memory bound 1573 * processes. This optimization causes one-time-use metadata to be 1574 * reused more quickly. 1575 * 1576 * BUT, if we are in a low-memory situation we have no choice but to 1577 * put clean pages on the cache queue. 1578 * 1579 * A number of routines use vm_page_unwire() to guarantee that the page 1580 * will go into either the inactive or active queues, and will NEVER 1581 * be placed in the cache - for example, just after dirtying a page. 1582 * dirty pages in the cache are not allowed. 1583 * 1584 * The page queues must be locked. 1585 * This routine may not block. 1586 */ 1587void 1588vm_page_unwire(vm_page_t m, int activate) 1589{ 1590 1591 if ((m->flags & PG_UNMANAGED) == 0) 1592 mtx_assert(&vm_page_queue_mtx, MA_OWNED); 1593 if (m->flags & PG_FICTITIOUS) 1594 return; 1595 if (m->wire_count > 0) { 1596 m->wire_count--; 1597 if (m->wire_count == 0) { 1598 atomic_subtract_int(&cnt.v_wire_count, 1); 1599 if (m->flags & PG_UNMANAGED) { 1600 ; 1601 } else if (activate) 1602 vm_page_enqueue(PQ_ACTIVE, m); 1603 else { 1604 vm_page_flag_clear(m, PG_WINATCFLS); 1605 vm_page_enqueue(PQ_INACTIVE, m); 1606 } 1607 } 1608 } else { 1609 panic("vm_page_unwire: invalid wire count: %d", m->wire_count); 1610 } 1611} 1612 1613 1614/* 1615 * Move the specified page to the inactive queue. If the page has 1616 * any associated swap, the swap is deallocated. 1617 * 1618 * Normally athead is 0 resulting in LRU operation. athead is set 1619 * to 1 if we want this page to be 'as if it were placed in the cache', 1620 * except without unmapping it from the process address space. 1621 * 1622 * This routine may not block. 1623 */ 1624static inline void 1625_vm_page_deactivate(vm_page_t m, int athead) 1626{ 1627 1628 mtx_assert(&vm_page_queue_mtx, MA_OWNED); 1629 1630 /* 1631 * Ignore if already inactive. 1632 */ 1633 if (VM_PAGE_INQUEUE2(m, PQ_INACTIVE)) 1634 return; 1635 if (m->wire_count == 0 && (m->flags & PG_UNMANAGED) == 0) { 1636 vm_page_flag_clear(m, PG_WINATCFLS); 1637 vm_pageq_remove(m); 1638 if (athead) 1639 TAILQ_INSERT_HEAD(&vm_page_queues[PQ_INACTIVE].pl, m, pageq); 1640 else 1641 TAILQ_INSERT_TAIL(&vm_page_queues[PQ_INACTIVE].pl, m, pageq); 1642 VM_PAGE_SETQUEUE2(m, PQ_INACTIVE); 1643 cnt.v_inactive_count++; 1644 } 1645} 1646 1647void 1648vm_page_deactivate(vm_page_t m) 1649{ 1650 _vm_page_deactivate(m, 0); 1651} 1652 1653/* 1654 * vm_page_try_to_cache: 1655 * 1656 * Returns 0 on failure, 1 on success 1657 */ 1658int 1659vm_page_try_to_cache(vm_page_t m) 1660{ 1661 1662 mtx_assert(&vm_page_queue_mtx, MA_OWNED); 1663 vm_page_lock_assert(m, MA_OWNED); 1664 VM_OBJECT_LOCK_ASSERT(m->object, MA_OWNED); 1665 if (m->dirty || m->hold_count || m->busy || m->wire_count || 1666 (m->oflags & VPO_BUSY) || (m->flags & PG_UNMANAGED)) { 1667 return (0); 1668 } 1669 pmap_remove_all(m); 1670 if (m->dirty) 1671 return (0); 1672 vm_page_cache(m); 1673 return (1); 1674} 1675 1676/* 1677 * vm_page_try_to_free() 1678 * 1679 * Attempt to free the page. If we cannot free it, we do nothing. 1680 * 1 is returned on success, 0 on failure. 1681 */ 1682int 1683vm_page_try_to_free(vm_page_t m) 1684{ 1685 1686 mtx_assert(&vm_page_queue_mtx, MA_OWNED); 1687 vm_page_lock_assert(m, MA_OWNED); 1688 if (m->object != NULL) 1689 VM_OBJECT_LOCK_ASSERT(m->object, MA_OWNED); 1690 if (m->dirty || m->hold_count || m->busy || m->wire_count || 1691 (m->oflags & VPO_BUSY) || (m->flags & PG_UNMANAGED)) { 1692 return (0); 1693 } 1694 pmap_remove_all(m); 1695 if (m->dirty) 1696 return (0); 1697 vm_page_free(m); 1698 return (1); 1699} 1700 1701/* 1702 * vm_page_cache 1703 * 1704 * Put the specified page onto the page cache queue (if appropriate). 1705 * 1706 * This routine may not block. 1707 */ 1708void 1709vm_page_cache(vm_page_t m) 1710{ 1711 vm_object_t object; 1712 vm_page_t root; 1713 1714 mtx_assert(&vm_page_queue_mtx, MA_OWNED); 1715 vm_page_lock_assert(m, MA_OWNED); 1716 object = m->object; 1717 VM_OBJECT_LOCK_ASSERT(object, MA_OWNED); 1718 if ((m->flags & PG_UNMANAGED) || (m->oflags & VPO_BUSY) || m->busy || 1719 m->hold_count || m->wire_count) { 1720 panic("vm_page_cache: attempting to cache busy page"); 1721 } 1722 pmap_remove_all(m); 1723 if (m->dirty != 0) 1724 panic("vm_page_cache: page %p is dirty", m); 1725 if (m->valid == 0 || object->type == OBJT_DEFAULT || 1726 (object->type == OBJT_SWAP && 1727 !vm_pager_has_page(object, m->pindex, NULL, NULL))) { 1728 /* 1729 * Hypothesis: A cache-elgible page belonging to a 1730 * default object or swap object but without a backing 1731 * store must be zero filled. 1732 */ 1733 vm_page_free(m); 1734 return; 1735 } 1736 KASSERT((m->flags & PG_CACHED) == 0, 1737 ("vm_page_cache: page %p is already cached", m)); 1738 cnt.v_tcached++; 1739 1740 /* 1741 * Remove the page from the paging queues. 1742 */ 1743 vm_pageq_remove(m); 1744 1745 /* 1746 * Remove the page from the object's collection of resident 1747 * pages. 1748 */ 1749 if (m != object->root) 1750 vm_page_splay(m->pindex, object->root); 1751 if (m->left == NULL) 1752 root = m->right; 1753 else { 1754 root = vm_page_splay(m->pindex, m->left); 1755 root->right = m->right; 1756 } 1757 object->root = root; 1758 TAILQ_REMOVE(&object->memq, m, listq); 1759 object->resident_page_count--; 1760 object->generation++; 1761 1762 /* 1763 * Restore the default memory attribute to the page. 1764 */ 1765 if (pmap_page_get_memattr(m) != VM_MEMATTR_DEFAULT) 1766 pmap_page_set_memattr(m, VM_MEMATTR_DEFAULT); 1767 1768 /* 1769 * Insert the page into the object's collection of cached pages 1770 * and the physical memory allocator's cache/free page queues. 1771 */ 1772 vm_page_flag_clear(m, PG_ZERO); 1773 mtx_lock(&vm_page_queue_free_mtx); 1774 m->flags |= PG_CACHED; 1775 cnt.v_cache_count++; 1776 root = object->cache; 1777 if (root == NULL) { 1778 m->left = NULL; 1779 m->right = NULL; 1780 } else { 1781 root = vm_page_splay(m->pindex, root); 1782 if (m->pindex < root->pindex) { 1783 m->left = root->left; 1784 m->right = root; 1785 root->left = NULL; 1786 } else if (__predict_false(m->pindex == root->pindex)) 1787 panic("vm_page_cache: offset already cached"); 1788 else { 1789 m->right = root->right; 1790 m->left = root; 1791 root->right = NULL; 1792 } 1793 } 1794 object->cache = m; 1795#if VM_NRESERVLEVEL > 0 1796 if (!vm_reserv_free_page(m)) { 1797#else 1798 if (TRUE) { 1799#endif 1800 vm_phys_set_pool(VM_FREEPOOL_CACHE, m, 0); 1801 vm_phys_free_pages(m, 0); 1802 } 1803 vm_page_free_wakeup(); 1804 mtx_unlock(&vm_page_queue_free_mtx); 1805 1806 /* 1807 * Increment the vnode's hold count if this is the object's only 1808 * cached page. Decrement the vnode's hold count if this was 1809 * the object's only resident page. 1810 */ 1811 if (object->type == OBJT_VNODE) { 1812 if (root == NULL && object->resident_page_count != 0) 1813 vhold(object->handle); 1814 else if (root != NULL && object->resident_page_count == 0) 1815 vdrop(object->handle); 1816 } 1817} 1818 1819/* 1820 * vm_page_dontneed 1821 * 1822 * Cache, deactivate, or do nothing as appropriate. This routine 1823 * is typically used by madvise() MADV_DONTNEED. 1824 * 1825 * Generally speaking we want to move the page into the cache so 1826 * it gets reused quickly. However, this can result in a silly syndrome 1827 * due to the page recycling too quickly. Small objects will not be 1828 * fully cached. On the otherhand, if we move the page to the inactive 1829 * queue we wind up with a problem whereby very large objects 1830 * unnecessarily blow away our inactive and cache queues. 1831 * 1832 * The solution is to move the pages based on a fixed weighting. We 1833 * either leave them alone, deactivate them, or move them to the cache, 1834 * where moving them to the cache has the highest weighting. 1835 * By forcing some pages into other queues we eventually force the 1836 * system to balance the queues, potentially recovering other unrelated 1837 * space from active. The idea is to not force this to happen too 1838 * often. 1839 */ 1840void 1841vm_page_dontneed(vm_page_t m) 1842{ 1843 static int dnweight; 1844 int dnw; 1845 int head; 1846 1847 mtx_assert(&vm_page_queue_mtx, MA_OWNED); 1848 dnw = ++dnweight; 1849 1850 /* 1851 * occassionally leave the page alone 1852 */ 1853 if ((dnw & 0x01F0) == 0 || 1854 VM_PAGE_INQUEUE2(m, PQ_INACTIVE)) { 1855 if (m->act_count >= ACT_INIT) 1856 --m->act_count; 1857 return; 1858 } 1859 1860 /* 1861 * Clear any references to the page. Otherwise, the page daemon will 1862 * immediately reactivate the page. 1863 */ 1864 vm_page_flag_clear(m, PG_REFERENCED); 1865 pmap_clear_reference(m); 1866 1867 if (m->dirty == 0 && pmap_is_modified(m)) 1868 vm_page_dirty(m); 1869 1870 if (m->dirty || (dnw & 0x0070) == 0) { 1871 /* 1872 * Deactivate the page 3 times out of 32. 1873 */ 1874 head = 0; 1875 } else { 1876 /* 1877 * Cache the page 28 times out of every 32. Note that 1878 * the page is deactivated instead of cached, but placed 1879 * at the head of the queue instead of the tail. 1880 */ 1881 head = 1; 1882 } 1883 _vm_page_deactivate(m, head); 1884} 1885 1886/* 1887 * Grab a page, waiting until we are waken up due to the page 1888 * changing state. We keep on waiting, if the page continues 1889 * to be in the object. If the page doesn't exist, first allocate it 1890 * and then conditionally zero it. 1891 * 1892 * This routine may block. 1893 */ 1894vm_page_t 1895vm_page_grab(vm_object_t object, vm_pindex_t pindex, int allocflags) 1896{ 1897 vm_page_t m; 1898 1899 VM_OBJECT_LOCK_ASSERT(object, MA_OWNED); 1900retrylookup: 1901 if ((m = vm_page_lookup(object, pindex)) != NULL) { 1902 if ((m->oflags & VPO_BUSY) != 0 || m->busy != 0) { 1903 if ((allocflags & VM_ALLOC_RETRY) != 0) { 1904 /* 1905 * Reference the page before unlocking and 1906 * sleeping so that the page daemon is less 1907 * likely to reclaim it. 1908 */ 1909 vm_page_lock_queues(); 1910 vm_page_flag_set(m, PG_REFERENCED); 1911 } 1912 vm_page_sleep(m, "pgrbwt"); 1913 if ((allocflags & VM_ALLOC_RETRY) == 0) 1914 return (NULL); 1915 goto retrylookup; 1916 } else { 1917 if ((allocflags & VM_ALLOC_WIRED) != 0) { 1918 vm_page_lock(m); 1919 vm_page_lock_queues(); 1920 vm_page_wire(m); 1921 vm_page_unlock_queues(); 1922 vm_page_unlock(m); 1923 } 1924 if ((allocflags & VM_ALLOC_NOBUSY) == 0) 1925 vm_page_busy(m); 1926 return (m); 1927 } 1928 } 1929 m = vm_page_alloc(object, pindex, allocflags & ~VM_ALLOC_RETRY); 1930 if (m == NULL) { 1931 VM_OBJECT_UNLOCK(object); 1932 VM_WAIT; 1933 VM_OBJECT_LOCK(object); 1934 if ((allocflags & VM_ALLOC_RETRY) == 0) 1935 return (NULL); 1936 goto retrylookup; 1937 } else if (m->valid != 0) 1938 return (m); 1939 if (allocflags & VM_ALLOC_ZERO && (m->flags & PG_ZERO) == 0) 1940 pmap_zero_page(m); 1941 return (m); 1942} 1943 1944/* 1945 * Mapping function for valid bits or for dirty bits in 1946 * a page. May not block. 1947 * 1948 * Inputs are required to range within a page. 1949 */ 1950int 1951vm_page_bits(int base, int size) 1952{ 1953 int first_bit; 1954 int last_bit; 1955 1956 KASSERT( 1957 base + size <= PAGE_SIZE, 1958 ("vm_page_bits: illegal base/size %d/%d", base, size) 1959 ); 1960 1961 if (size == 0) /* handle degenerate case */ 1962 return (0); 1963 1964 first_bit = base >> DEV_BSHIFT; 1965 last_bit = (base + size - 1) >> DEV_BSHIFT; 1966 1967 return ((2 << last_bit) - (1 << first_bit)); 1968} 1969 1970/* 1971 * vm_page_set_valid: 1972 * 1973 * Sets portions of a page valid. The arguments are expected 1974 * to be DEV_BSIZE aligned but if they aren't the bitmap is inclusive 1975 * of any partial chunks touched by the range. The invalid portion of 1976 * such chunks will be zeroed. 1977 * 1978 * (base + size) must be less then or equal to PAGE_SIZE. 1979 */ 1980void 1981vm_page_set_valid(vm_page_t m, int base, int size) 1982{ 1983 int endoff, frag; 1984 1985 VM_OBJECT_LOCK_ASSERT(m->object, MA_OWNED); 1986 if (size == 0) /* handle degenerate case */ 1987 return; 1988 1989 /* 1990 * If the base is not DEV_BSIZE aligned and the valid 1991 * bit is clear, we have to zero out a portion of the 1992 * first block. 1993 */ 1994 if ((frag = base & ~(DEV_BSIZE - 1)) != base && 1995 (m->valid & (1 << (base >> DEV_BSHIFT))) == 0) 1996 pmap_zero_page_area(m, frag, base - frag); 1997 1998 /* 1999 * If the ending offset is not DEV_BSIZE aligned and the 2000 * valid bit is clear, we have to zero out a portion of 2001 * the last block. 2002 */ 2003 endoff = base + size; 2004 if ((frag = endoff & ~(DEV_BSIZE - 1)) != endoff && 2005 (m->valid & (1 << (endoff >> DEV_BSHIFT))) == 0) 2006 pmap_zero_page_area(m, endoff, 2007 DEV_BSIZE - (endoff & (DEV_BSIZE - 1))); 2008 2009 /* 2010 * Assert that no previously invalid block that is now being validated 2011 * is already dirty. 2012 */ 2013 KASSERT((~m->valid & vm_page_bits(base, size) & m->dirty) == 0, 2014 ("vm_page_set_valid: page %p is dirty", m)); 2015 2016 /* 2017 * Set valid bits inclusive of any overlap. 2018 */ 2019 m->valid |= vm_page_bits(base, size); 2020} 2021 2022/* 2023 * vm_page_set_validclean: 2024 * 2025 * Sets portions of a page valid and clean. The arguments are expected 2026 * to be DEV_BSIZE aligned but if they aren't the bitmap is inclusive 2027 * of any partial chunks touched by the range. The invalid portion of 2028 * such chunks will be zero'd. 2029 * 2030 * This routine may not block. 2031 * 2032 * (base + size) must be less then or equal to PAGE_SIZE. 2033 */ 2034void 2035vm_page_set_validclean(vm_page_t m, int base, int size) 2036{ 2037 int pagebits; 2038 int frag; 2039 int endoff; 2040 2041 mtx_assert(&vm_page_queue_mtx, MA_OWNED); 2042 VM_OBJECT_LOCK_ASSERT(m->object, MA_OWNED); 2043 if (size == 0) /* handle degenerate case */ 2044 return; 2045 2046 /* 2047 * If the base is not DEV_BSIZE aligned and the valid 2048 * bit is clear, we have to zero out a portion of the 2049 * first block. 2050 */ 2051 if ((frag = base & ~(DEV_BSIZE - 1)) != base && 2052 (m->valid & (1 << (base >> DEV_BSHIFT))) == 0) 2053 pmap_zero_page_area(m, frag, base - frag); 2054 2055 /* 2056 * If the ending offset is not DEV_BSIZE aligned and the 2057 * valid bit is clear, we have to zero out a portion of 2058 * the last block. 2059 */ 2060 endoff = base + size; 2061 if ((frag = endoff & ~(DEV_BSIZE - 1)) != endoff && 2062 (m->valid & (1 << (endoff >> DEV_BSHIFT))) == 0) 2063 pmap_zero_page_area(m, endoff, 2064 DEV_BSIZE - (endoff & (DEV_BSIZE - 1))); 2065 2066 /* 2067 * Set valid, clear dirty bits. If validating the entire 2068 * page we can safely clear the pmap modify bit. We also 2069 * use this opportunity to clear the VPO_NOSYNC flag. If a process 2070 * takes a write fault on a MAP_NOSYNC memory area the flag will 2071 * be set again. 2072 * 2073 * We set valid bits inclusive of any overlap, but we can only 2074 * clear dirty bits for DEV_BSIZE chunks that are fully within 2075 * the range. 2076 */ 2077 pagebits = vm_page_bits(base, size); 2078 m->valid |= pagebits; 2079#if 0 /* NOT YET */ 2080 if ((frag = base & (DEV_BSIZE - 1)) != 0) { 2081 frag = DEV_BSIZE - frag; 2082 base += frag; 2083 size -= frag; 2084 if (size < 0) 2085 size = 0; 2086 } 2087 pagebits = vm_page_bits(base, size & (DEV_BSIZE - 1)); 2088#endif 2089 m->dirty &= ~pagebits; 2090 if (base == 0 && size == PAGE_SIZE) { 2091 pmap_clear_modify(m); 2092 m->oflags &= ~VPO_NOSYNC; 2093 } 2094} 2095 2096void 2097vm_page_clear_dirty(vm_page_t m, int base, int size) 2098{ 2099 2100 mtx_assert(&vm_page_queue_mtx, MA_OWNED); 2101 m->dirty &= ~vm_page_bits(base, size); 2102} 2103 2104/* 2105 * vm_page_set_invalid: 2106 * 2107 * Invalidates DEV_BSIZE'd chunks within a page. Both the 2108 * valid and dirty bits for the effected areas are cleared. 2109 * 2110 * May not block. 2111 */ 2112void 2113vm_page_set_invalid(vm_page_t m, int base, int size) 2114{ 2115 int bits; 2116 2117 VM_OBJECT_LOCK_ASSERT(m->object, MA_OWNED); 2118 bits = vm_page_bits(base, size); 2119 mtx_assert(&vm_page_queue_mtx, MA_OWNED); 2120 if (m->valid == VM_PAGE_BITS_ALL && bits != 0) 2121 pmap_remove_all(m); 2122 m->valid &= ~bits; 2123 m->dirty &= ~bits; 2124 m->object->generation++; 2125} 2126 2127/* 2128 * vm_page_zero_invalid() 2129 * 2130 * The kernel assumes that the invalid portions of a page contain 2131 * garbage, but such pages can be mapped into memory by user code. 2132 * When this occurs, we must zero out the non-valid portions of the 2133 * page so user code sees what it expects. 2134 * 2135 * Pages are most often semi-valid when the end of a file is mapped 2136 * into memory and the file's size is not page aligned. 2137 */ 2138void 2139vm_page_zero_invalid(vm_page_t m, boolean_t setvalid) 2140{ 2141 int b; 2142 int i; 2143 2144 VM_OBJECT_LOCK_ASSERT(m->object, MA_OWNED); 2145 /* 2146 * Scan the valid bits looking for invalid sections that 2147 * must be zerod. Invalid sub-DEV_BSIZE'd areas ( where the 2148 * valid bit may be set ) have already been zerod by 2149 * vm_page_set_validclean(). 2150 */ 2151 for (b = i = 0; i <= PAGE_SIZE / DEV_BSIZE; ++i) { 2152 if (i == (PAGE_SIZE / DEV_BSIZE) || 2153 (m->valid & (1 << i)) 2154 ) { 2155 if (i > b) { 2156 pmap_zero_page_area(m, 2157 b << DEV_BSHIFT, (i - b) << DEV_BSHIFT); 2158 } 2159 b = i + 1; 2160 } 2161 } 2162 2163 /* 2164 * setvalid is TRUE when we can safely set the zero'd areas 2165 * as being valid. We can do this if there are no cache consistancy 2166 * issues. e.g. it is ok to do with UFS, but not ok to do with NFS. 2167 */ 2168 if (setvalid) 2169 m->valid = VM_PAGE_BITS_ALL; 2170} 2171 2172/* 2173 * vm_page_is_valid: 2174 * 2175 * Is (partial) page valid? Note that the case where size == 0 2176 * will return FALSE in the degenerate case where the page is 2177 * entirely invalid, and TRUE otherwise. 2178 * 2179 * May not block. 2180 */ 2181int 2182vm_page_is_valid(vm_page_t m, int base, int size) 2183{ 2184 int bits = vm_page_bits(base, size); 2185 2186 VM_OBJECT_LOCK_ASSERT(m->object, MA_OWNED); 2187 if (m->valid && ((m->valid & bits) == bits)) 2188 return 1; 2189 else 2190 return 0; 2191} 2192 2193/* 2194 * update dirty bits from pmap/mmu. May not block. 2195 */ 2196void 2197vm_page_test_dirty(vm_page_t m) 2198{ 2199 if ((m->dirty != VM_PAGE_BITS_ALL) && pmap_is_modified(m)) { 2200 vm_page_dirty(m); 2201 } 2202} 2203 2204int so_zerocp_fullpage = 0; 2205 2206/* 2207 * Replace the given page with a copy. The copied page assumes 2208 * the portion of the given page's "wire_count" that is not the 2209 * responsibility of this copy-on-write mechanism. 2210 * 2211 * The object containing the given page must have a non-zero 2212 * paging-in-progress count and be locked. 2213 */ 2214void 2215vm_page_cowfault(vm_page_t m) 2216{ 2217 vm_page_t mnew; 2218 vm_object_t object; 2219 vm_pindex_t pindex; 2220 2221 object = m->object; 2222 VM_OBJECT_LOCK_ASSERT(object, MA_OWNED); 2223 KASSERT(object->paging_in_progress != 0, 2224 ("vm_page_cowfault: object %p's paging-in-progress count is zero.", 2225 object)); 2226 pindex = m->pindex; 2227 2228 retry_alloc: 2229 pmap_remove_all(m); 2230 vm_page_remove(m); 2231 mnew = vm_page_alloc(object, pindex, VM_ALLOC_NORMAL | VM_ALLOC_NOBUSY); 2232 if (mnew == NULL) { 2233 vm_page_insert(m, object, pindex); 2234 vm_page_unlock_queues(); 2235 VM_OBJECT_UNLOCK(object); 2236 VM_WAIT; 2237 VM_OBJECT_LOCK(object); 2238 if (m == vm_page_lookup(object, pindex)) { 2239 vm_page_lock_queues(); 2240 goto retry_alloc; 2241 } else { 2242 /* 2243 * Page disappeared during the wait. 2244 */ 2245 vm_page_lock_queues(); 2246 return; 2247 } 2248 } 2249 2250 if (m->cow == 0) { 2251 /* 2252 * check to see if we raced with an xmit complete when 2253 * waiting to allocate a page. If so, put things back 2254 * the way they were 2255 */ 2256 vm_page_free(mnew); 2257 vm_page_insert(m, object, pindex); 2258 } else { /* clear COW & copy page */ 2259 if (!so_zerocp_fullpage) 2260 pmap_copy_page(m, mnew); 2261 mnew->valid = VM_PAGE_BITS_ALL; 2262 vm_page_dirty(mnew); 2263 mnew->wire_count = m->wire_count - m->cow; 2264 m->wire_count = m->cow; 2265 } 2266} 2267 2268void 2269vm_page_cowclear(vm_page_t m) 2270{ 2271 2272 mtx_assert(&vm_page_queue_mtx, MA_OWNED); 2273 if (m->cow) { 2274 m->cow--; 2275 /* 2276 * let vm_fault add back write permission lazily 2277 */ 2278 } 2279 /* 2280 * sf_buf_free() will free the page, so we needn't do it here 2281 */ 2282} 2283 2284int 2285vm_page_cowsetup(vm_page_t m) 2286{ 2287 2288 mtx_assert(&vm_page_queue_mtx, MA_OWNED); 2289 if (m->cow == USHRT_MAX - 1) 2290 return (EBUSY); 2291 m->cow++; 2292 pmap_remove_write(m); 2293 return (0); 2294} 2295 2296#include "opt_ddb.h" 2297#ifdef DDB 2298#include <sys/kernel.h> 2299 2300#include <ddb/ddb.h> 2301 2302DB_SHOW_COMMAND(page, vm_page_print_page_info) 2303{ 2304 db_printf("cnt.v_free_count: %d\n", cnt.v_free_count); 2305 db_printf("cnt.v_cache_count: %d\n", cnt.v_cache_count); 2306 db_printf("cnt.v_inactive_count: %d\n", cnt.v_inactive_count); 2307 db_printf("cnt.v_active_count: %d\n", cnt.v_active_count); 2308 db_printf("cnt.v_wire_count: %d\n", cnt.v_wire_count); 2309 db_printf("cnt.v_free_reserved: %d\n", cnt.v_free_reserved); 2310 db_printf("cnt.v_free_min: %d\n", cnt.v_free_min); 2311 db_printf("cnt.v_free_target: %d\n", cnt.v_free_target); 2312 db_printf("cnt.v_cache_min: %d\n", cnt.v_cache_min); 2313 db_printf("cnt.v_inactive_target: %d\n", cnt.v_inactive_target); 2314} 2315 2316DB_SHOW_COMMAND(pageq, vm_page_print_pageq_info) 2317{ 2318 2319 db_printf("PQ_FREE:"); 2320 db_printf(" %d", cnt.v_free_count); 2321 db_printf("\n"); 2322 2323 db_printf("PQ_CACHE:"); 2324 db_printf(" %d", cnt.v_cache_count); 2325 db_printf("\n"); 2326 2327 db_printf("PQ_ACTIVE: %d, PQ_INACTIVE: %d\n", 2328 *vm_page_queues[PQ_ACTIVE].cnt, 2329 *vm_page_queues[PQ_INACTIVE].cnt); 2330} 2331#endif /* DDB */ 2332