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("$FreeBSD$"); 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/msgbuf.h> 112 #include <sys/mutex.h> 113 #include <sys/proc.h> 114 #include <sys/sysctl.h> 115 #include <sys/vmmeter.h> 116 #include <sys/vnode.h> 117 118 #include <vm/vm.h> 119 #include <vm/pmap.h> 120 #include <vm/vm_param.h> 121 #include <vm/vm_kern.h> 122 #include <vm/vm_object.h> 123 #include <vm/vm_page.h> 124 #include <vm/vm_pageout.h> 125 #include <vm/vm_pager.h> 126 #include <vm/vm_phys.h> 127 #include <vm/vm_reserv.h> 128 #include <vm/vm_extern.h> 129 #include <vm/uma.h> 130 #include <vm/uma_int.h> 131 132 #include <machine/md_var.h> 133 134 #if defined(__amd64__) || defined (__i386__) 135 extern struct sysctl_oid_list sysctl__vm_pmap_children; 136 #else 137 SYSCTL_NODE(_vm, OID_AUTO, pmap, CTLFLAG_RD, 0, "VM/pmap parameters"); 138 #endif 139 140 static uint64_t pmap_tryrelock_calls; 141 SYSCTL_QUAD(_vm_pmap, OID_AUTO, tryrelock_calls, CTLFLAG_RD, 142 &pmap_tryrelock_calls, 0, "Number of tryrelock calls"); 143 144 static int pmap_tryrelock_restart; 145 SYSCTL_INT(_vm_pmap, OID_AUTO, tryrelock_restart, CTLFLAG_RD, 146 &pmap_tryrelock_restart, 0, "Number of tryrelock restarts"); 147 148 static int pmap_tryrelock_race; 149 SYSCTL_INT(_vm_pmap, OID_AUTO, tryrelock_race, CTLFLAG_RD, 150 &pmap_tryrelock_race, 0, "Number of tryrelock pmap race cases"); 151 152 /* 153 * Associated with page of user-allocatable memory is a 154 * page structure. 155 */ 156 157 struct vpgqueues vm_page_queues[PQ_COUNT]; 158 struct vpglocks vm_page_queue_lock; 159 struct vpglocks vm_page_queue_free_lock; 160 161 struct vpglocks pa_lock[PA_LOCK_COUNT] __aligned(CACHE_LINE_SIZE); 162 163 vm_page_t vm_page_array = 0; 164 int vm_page_array_size = 0; 165 long first_page = 0; 166 int vm_page_zero_count = 0; 167 168 static int boot_pages = UMA_BOOT_PAGES; 169 TUNABLE_INT("vm.boot_pages", &boot_pages); 170 SYSCTL_INT(_vm, OID_AUTO, boot_pages, CTLFLAG_RD, &boot_pages, 0, 171 "number of pages allocated for bootstrapping the VM system"); 172 173 static void vm_page_clear_dirty_mask(vm_page_t m, int pagebits); 174 static void vm_page_queue_remove(int queue, vm_page_t m); 175 static void vm_page_enqueue(int queue, vm_page_t m); 176 177 /* Make sure that u_long is at least 64 bits when PAGE_SIZE is 32K. */ 178 #if PAGE_SIZE == 32768 179 #ifdef CTASSERT 180 CTASSERT(sizeof(u_long) >= 8); 181 #endif 182 #endif 183 184 /* 185 * Try to acquire a physical address lock while a pmap is locked. If we 186 * fail to trylock we unlock and lock the pmap directly and cache the 187 * locked pa in *locked. The caller should then restart their loop in case 188 * the virtual to physical mapping has changed. 189 */ 190 int 191 vm_page_pa_tryrelock(pmap_t pmap, vm_paddr_t pa, vm_paddr_t *locked) 192 { 193 vm_paddr_t lockpa; 194 uint32_t gen_count; 195 196 gen_count = pmap->pm_gen_count; 197 atomic_add_long((volatile long *)&pmap_tryrelock_calls, 1); 198 lockpa = *locked; 199 *locked = pa; 200 if (lockpa) { 201 PA_LOCK_ASSERT(lockpa, MA_OWNED); 202 if (PA_LOCKPTR(pa) == PA_LOCKPTR(lockpa)) 203 return (0); 204 PA_UNLOCK(lockpa); 205 } 206 if (PA_TRYLOCK(pa)) 207 return (0); 208 PMAP_UNLOCK(pmap); 209 atomic_add_int((volatile int *)&pmap_tryrelock_restart, 1); 210 PA_LOCK(pa); 211 PMAP_LOCK(pmap); 212 213 if (pmap->pm_gen_count != gen_count + 1) { 214 pmap->pm_retries++; 215 atomic_add_int((volatile int *)&pmap_tryrelock_race, 1); 216 return (EAGAIN); 217 } 218 return (0); 219 } 220 221 /* 222 * vm_set_page_size: 223 * 224 * Sets the page size, perhaps based upon the memory 225 * size. Must be called before any use of page-size 226 * dependent functions. 227 */ 228 void 229 vm_set_page_size(void) 230 { 231 if (cnt.v_page_size == 0) 232 cnt.v_page_size = PAGE_SIZE; 233 if (((cnt.v_page_size - 1) & cnt.v_page_size) != 0) 234 panic("vm_set_page_size: page size not a power of two"); 235 } 236 237 /* 238 * vm_page_blacklist_lookup: 239 * 240 * See if a physical address in this page has been listed 241 * in the blacklist tunable. Entries in the tunable are 242 * separated by spaces or commas. If an invalid integer is 243 * encountered then the rest of the string is skipped. 244 */ 245 static int 246 vm_page_blacklist_lookup(char *list, vm_paddr_t pa) 247 { 248 vm_paddr_t bad; 249 char *cp, *pos; 250 251 for (pos = list; *pos != '\0'; pos = cp) { 252 bad = strtoq(pos, &cp, 0); 253 if (*cp != '\0') { 254 if (*cp == ' ' || *cp == ',') { 255 cp++; 256 if (cp == pos) 257 continue; 258 } else 259 break; 260 } 261 if (pa == trunc_page(bad)) 262 return (1); 263 } 264 return (0); 265 } 266 267 /* 268 * vm_page_startup: 269 * 270 * Initializes the resident memory module. 271 * 272 * Allocates memory for the page cells, and 273 * for the object/offset-to-page hash table headers. 274 * Each page cell is initialized and placed on the free list. 275 */ 276 vm_offset_t 277 vm_page_startup(vm_offset_t vaddr) 278 { 279 vm_offset_t mapped; 280 vm_paddr_t page_range; 281 vm_paddr_t new_end; 282 int i; 283 vm_paddr_t pa; 284 int nblocks; 285 vm_paddr_t last_pa; 286 char *list; 287 288 /* the biggest memory array is the second group of pages */ 289 vm_paddr_t end; 290 vm_paddr_t biggestsize; 291 vm_paddr_t low_water, high_water; 292 int biggestone; 293 294 biggestsize = 0; 295 biggestone = 0; 296 nblocks = 0; 297 vaddr = round_page(vaddr); 298 299 for (i = 0; phys_avail[i + 1]; i += 2) { 300 phys_avail[i] = round_page(phys_avail[i]); 301 phys_avail[i + 1] = trunc_page(phys_avail[i + 1]); 302 } 303 304 low_water = phys_avail[0]; 305 high_water = phys_avail[1]; 306 307 for (i = 0; phys_avail[i + 1]; i += 2) { 308 vm_paddr_t size = phys_avail[i + 1] - phys_avail[i]; 309 310 if (size > biggestsize) { 311 biggestone = i; 312 biggestsize = size; 313 } 314 if (phys_avail[i] < low_water) 315 low_water = phys_avail[i]; 316 if (phys_avail[i + 1] > high_water) 317 high_water = phys_avail[i + 1]; 318 ++nblocks; 319 } 320 321 #ifdef XEN 322 low_water = 0; 323 #endif 324 325 end = phys_avail[biggestone+1]; 326 327 /* 328 * Initialize the locks. 329 */ 330 mtx_init(&vm_page_queue_mtx, "vm page queue mutex", NULL, MTX_DEF | 331 MTX_RECURSE); 332 mtx_init(&vm_page_queue_free_mtx, "vm page queue free mutex", NULL, 333 MTX_DEF); 334 335 /* Setup page locks. */ 336 for (i = 0; i < PA_LOCK_COUNT; i++) 337 mtx_init(&pa_lock[i].data, "page lock", NULL, 338 MTX_DEF | MTX_RECURSE | MTX_DUPOK); 339 340 /* 341 * Initialize the queue headers for the hold queue, the active queue, 342 * and the inactive queue. 343 */ 344 for (i = 0; i < PQ_COUNT; i++) 345 TAILQ_INIT(&vm_page_queues[i].pl); 346 vm_page_queues[PQ_INACTIVE].cnt = &cnt.v_inactive_count; 347 vm_page_queues[PQ_ACTIVE].cnt = &cnt.v_active_count; 348 vm_page_queues[PQ_HOLD].cnt = &cnt.v_active_count; 349 350 /* 351 * Allocate memory for use when boot strapping the kernel memory 352 * allocator. 353 */ 354 new_end = end - (boot_pages * UMA_SLAB_SIZE); 355 new_end = trunc_page(new_end); 356 mapped = pmap_map(&vaddr, new_end, end, 357 VM_PROT_READ | VM_PROT_WRITE); 358 bzero((void *)mapped, end - new_end); 359 uma_startup((void *)mapped, boot_pages); 360 361 #if defined(__amd64__) || defined(__i386__) || defined(__arm__) 362 /* 363 * Allocate a bitmap to indicate that a random physical page 364 * needs to be included in a minidump. 365 * 366 * The amd64 port needs this to indicate which direct map pages 367 * need to be dumped, via calls to dump_add_page()/dump_drop_page(). 368 * 369 * However, i386 still needs this workspace internally within the 370 * minidump code. In theory, they are not needed on i386, but are 371 * included should the sf_buf code decide to use them. 372 */ 373 page_range = phys_avail[(nblocks - 1) * 2 + 1] / PAGE_SIZE; 374 vm_page_dump_size = round_page(roundup2(page_range, NBBY) / NBBY); 375 new_end -= vm_page_dump_size; 376 vm_page_dump = (void *)(uintptr_t)pmap_map(&vaddr, new_end, 377 new_end + vm_page_dump_size, VM_PROT_READ | VM_PROT_WRITE); 378 bzero((void *)vm_page_dump, vm_page_dump_size); 379 #endif 380 #ifdef __amd64__ 381 /* 382 * Request that the physical pages underlying the message buffer be 383 * included in a crash dump. Since the message buffer is accessed 384 * through the direct map, they are not automatically included. 385 */ 386 pa = DMAP_TO_PHYS((vm_offset_t)msgbufp->msg_ptr); 387 last_pa = pa + round_page(MSGBUF_SIZE); 388 while (pa < last_pa) { 389 dump_add_page(pa); 390 pa += PAGE_SIZE; 391 } 392 #endif 393 /* 394 * Compute the number of pages of memory that will be available for 395 * use (taking into account the overhead of a page structure per 396 * page). 397 */ 398 first_page = low_water / PAGE_SIZE; 399 #ifdef VM_PHYSSEG_SPARSE 400 page_range = 0; 401 for (i = 0; phys_avail[i + 1] != 0; i += 2) 402 page_range += atop(phys_avail[i + 1] - phys_avail[i]); 403 #elif defined(VM_PHYSSEG_DENSE) 404 page_range = high_water / PAGE_SIZE - first_page; 405 #else 406 #error "Either VM_PHYSSEG_DENSE or VM_PHYSSEG_SPARSE must be defined." 407 #endif 408 end = new_end; 409 410 /* 411 * Reserve an unmapped guard page to trap access to vm_page_array[-1]. 412 */ 413 vaddr += PAGE_SIZE; 414 415 /* 416 * Initialize the mem entry structures now, and put them in the free 417 * queue. 418 */ 419 new_end = trunc_page(end - page_range * sizeof(struct vm_page)); 420 mapped = pmap_map(&vaddr, new_end, end, 421 VM_PROT_READ | VM_PROT_WRITE); 422 vm_page_array = (vm_page_t) mapped; 423 #if VM_NRESERVLEVEL > 0 424 /* 425 * Allocate memory for the reservation management system's data 426 * structures. 427 */ 428 new_end = vm_reserv_startup(&vaddr, new_end, high_water); 429 #endif 430 #ifdef __amd64__ 431 /* 432 * pmap_map on amd64 comes out of the direct-map, not kvm like i386, 433 * so the pages must be tracked for a crashdump to include this data. 434 * This includes the vm_page_array and the early UMA bootstrap pages. 435 */ 436 for (pa = new_end; pa < phys_avail[biggestone + 1]; pa += PAGE_SIZE) 437 dump_add_page(pa); 438 #endif 439 phys_avail[biggestone + 1] = new_end; 440 441 /* 442 * Clear all of the page structures 443 */ 444 bzero((caddr_t) vm_page_array, page_range * sizeof(struct vm_page)); 445 for (i = 0; i < page_range; i++) 446 vm_page_array[i].order = VM_NFREEORDER; 447 vm_page_array_size = page_range; 448 449 /* 450 * Initialize the physical memory allocator. 451 */ 452 vm_phys_init(); 453 454 /* 455 * Add every available physical page that is not blacklisted to 456 * the free lists. 457 */ 458 cnt.v_page_count = 0; 459 cnt.v_free_count = 0; 460 list = getenv("vm.blacklist"); 461 for (i = 0; phys_avail[i + 1] != 0; i += 2) { 462 pa = phys_avail[i]; 463 last_pa = phys_avail[i + 1]; 464 while (pa < last_pa) { 465 if (list != NULL && 466 vm_page_blacklist_lookup(list, pa)) 467 printf("Skipping page with pa 0x%jx\n", 468 (uintmax_t)pa); 469 else 470 vm_phys_add_page(pa); 471 pa += PAGE_SIZE; 472 } 473 } 474 freeenv(list); 475 #if VM_NRESERVLEVEL > 0 476 /* 477 * Initialize the reservation management system. 478 */ 479 vm_reserv_init(); 480 #endif 481 return (vaddr); 482 } 483 484 void 485 vm_page_flag_set(vm_page_t m, unsigned short bits) 486 { 487 488 mtx_assert(&vm_page_queue_mtx, MA_OWNED); 489 m->flags |= bits; 490 } 491 492 void 493 vm_page_flag_clear(vm_page_t m, unsigned short bits) 494 { 495 496 mtx_assert(&vm_page_queue_mtx, MA_OWNED); 497 m->flags &= ~bits; 498 } 499 500 void 501 vm_page_busy(vm_page_t m) 502 { 503 504 VM_OBJECT_LOCK_ASSERT(m->object, MA_OWNED); 505 KASSERT((m->oflags & VPO_BUSY) == 0, 506 ("vm_page_busy: page already busy!!!")); 507 m->oflags |= VPO_BUSY; 508 } 509 510 /* 511 * vm_page_flash: 512 * 513 * wakeup anyone waiting for the page. 514 */ 515 void 516 vm_page_flash(vm_page_t m) 517 { 518 519 VM_OBJECT_LOCK_ASSERT(m->object, MA_OWNED); 520 if (m->oflags & VPO_WANTED) { 521 m->oflags &= ~VPO_WANTED; 522 wakeup(m); 523 } 524 } 525 526 /* 527 * vm_page_wakeup: 528 * 529 * clear the VPO_BUSY flag and wakeup anyone waiting for the 530 * page. 531 * 532 */ 533 void 534 vm_page_wakeup(vm_page_t m) 535 { 536 537 VM_OBJECT_LOCK_ASSERT(m->object, MA_OWNED); 538 KASSERT(m->oflags & VPO_BUSY, ("vm_page_wakeup: page not busy!!!")); 539 m->oflags &= ~VPO_BUSY; 540 vm_page_flash(m); 541 } 542 543 void 544 vm_page_io_start(vm_page_t m) 545 { 546 547 VM_OBJECT_LOCK_ASSERT(m->object, MA_OWNED); 548 m->busy++; 549 } 550 551 void 552 vm_page_io_finish(vm_page_t m) 553 { 554 555 VM_OBJECT_LOCK_ASSERT(m->object, MA_OWNED); 556 m->busy--; 557 if (m->busy == 0) 558 vm_page_flash(m); 559 } 560 561 /* 562 * Keep page from being freed by the page daemon 563 * much of the same effect as wiring, except much lower 564 * overhead and should be used only for *very* temporary 565 * holding ("wiring"). 566 */ 567 void 568 vm_page_hold(vm_page_t mem) 569 { 570 571 vm_page_lock_assert(mem, MA_OWNED); 572 mem->hold_count++; 573 } 574 575 void 576 vm_page_unhold(vm_page_t mem) 577 { 578 579 vm_page_lock_assert(mem, MA_OWNED); 580 --mem->hold_count; 581 KASSERT(mem->hold_count >= 0, ("vm_page_unhold: hold count < 0!!!")); 582 if (mem->hold_count == 0 && VM_PAGE_INQUEUE2(mem, PQ_HOLD)) 583 vm_page_free_toq(mem); 584 } 585 586 /* 587 * vm_page_free: 588 * 589 * Free a page. 590 */ 591 void 592 vm_page_free(vm_page_t m) 593 { 594 595 m->flags &= ~PG_ZERO; 596 vm_page_free_toq(m); 597 } 598 599 /* 600 * vm_page_free_zero: 601 * 602 * Free a page to the zerod-pages queue 603 */ 604 void 605 vm_page_free_zero(vm_page_t m) 606 { 607 608 m->flags |= PG_ZERO; 609 vm_page_free_toq(m); 610 } 611 612 /* 613 * vm_page_sleep: 614 * 615 * Sleep and release the page and page queues locks. 616 * 617 * The object containing the given page must be locked. 618 */ 619 void 620 vm_page_sleep(vm_page_t m, const char *msg) 621 { 622 623 VM_OBJECT_LOCK_ASSERT(m->object, MA_OWNED); 624 if (mtx_owned(&vm_page_queue_mtx)) 625 vm_page_unlock_queues(); 626 if (mtx_owned(vm_page_lockptr(m))) 627 vm_page_unlock(m); 628 629 /* 630 * It's possible that while we sleep, the page will get 631 * unbusied and freed. If we are holding the object 632 * lock, we will assume we hold a reference to the object 633 * such that even if m->object changes, we can re-lock 634 * it. 635 */ 636 m->oflags |= VPO_WANTED; 637 msleep(m, VM_OBJECT_MTX(m->object), PVM, msg, 0); 638 } 639 640 /* 641 * vm_page_dirty: 642 * 643 * make page all dirty 644 */ 645 void 646 vm_page_dirty(vm_page_t m) 647 { 648 649 KASSERT((m->flags & PG_CACHED) == 0, 650 ("vm_page_dirty: page in cache!")); 651 KASSERT(!VM_PAGE_IS_FREE(m), 652 ("vm_page_dirty: page is free!")); 653 KASSERT(m->valid == VM_PAGE_BITS_ALL, 654 ("vm_page_dirty: page is invalid!")); 655 m->dirty = VM_PAGE_BITS_ALL; 656 } 657 658 /* 659 * vm_page_splay: 660 * 661 * Implements Sleator and Tarjan's top-down splay algorithm. Returns 662 * the vm_page containing the given pindex. If, however, that 663 * pindex is not found in the vm_object, returns a vm_page that is 664 * adjacent to the pindex, coming before or after it. 665 */ 666 vm_page_t 667 vm_page_splay(vm_pindex_t pindex, vm_page_t root) 668 { 669 struct vm_page dummy; 670 vm_page_t lefttreemax, righttreemin, y; 671 672 if (root == NULL) 673 return (root); 674 lefttreemax = righttreemin = &dummy; 675 for (;; root = y) { 676 if (pindex < root->pindex) { 677 if ((y = root->left) == NULL) 678 break; 679 if (pindex < y->pindex) { 680 /* Rotate right. */ 681 root->left = y->right; 682 y->right = root; 683 root = y; 684 if ((y = root->left) == NULL) 685 break; 686 } 687 /* Link into the new root's right tree. */ 688 righttreemin->left = root; 689 righttreemin = root; 690 } else if (pindex > root->pindex) { 691 if ((y = root->right) == NULL) 692 break; 693 if (pindex > y->pindex) { 694 /* Rotate left. */ 695 root->right = y->left; 696 y->left = root; 697 root = y; 698 if ((y = root->right) == NULL) 699 break; 700 } 701 /* Link into the new root's left tree. */ 702 lefttreemax->right = root; 703 lefttreemax = root; 704 } else 705 break; 706 } 707 /* Assemble the new root. */ 708 lefttreemax->right = root->left; 709 righttreemin->left = root->right; 710 root->left = dummy.right; 711 root->right = dummy.left; 712 return (root); 713 } 714 715 /* 716 * vm_page_insert: [ internal use only ] 717 * 718 * Inserts the given mem entry into the object and object list. 719 * 720 * The pagetables are not updated but will presumably fault the page 721 * in if necessary, or if a kernel page the caller will at some point 722 * enter the page into the kernel's pmap. We are not allowed to block 723 * here so we *can't* do this anyway. 724 * 725 * The object and page must be locked. 726 * This routine may not block. 727 */ 728 void 729 vm_page_insert(vm_page_t m, vm_object_t object, vm_pindex_t pindex) 730 { 731 vm_page_t root; 732 733 VM_OBJECT_LOCK_ASSERT(object, MA_OWNED); 734 if (m->object != NULL) 735 panic("vm_page_insert: page already inserted"); 736 737 /* 738 * Record the object/offset pair in this page 739 */ 740 m->object = object; 741 m->pindex = pindex; 742 743 /* 744 * Now link into the object's ordered list of backed pages. 745 */ 746 root = object->root; 747 if (root == NULL) { 748 m->left = NULL; 749 m->right = NULL; 750 TAILQ_INSERT_TAIL(&object->memq, m, listq); 751 } else { 752 root = vm_page_splay(pindex, root); 753 if (pindex < root->pindex) { 754 m->left = root->left; 755 m->right = root; 756 root->left = NULL; 757 TAILQ_INSERT_BEFORE(root, m, listq); 758 } else if (pindex == root->pindex) 759 panic("vm_page_insert: offset already allocated"); 760 else { 761 m->right = root->right; 762 m->left = root; 763 root->right = NULL; 764 TAILQ_INSERT_AFTER(&object->memq, root, m, listq); 765 } 766 } 767 object->root = m; 768 object->generation++; 769 770 /* 771 * show that the object has one more resident page. 772 */ 773 object->resident_page_count++; 774 /* 775 * Hold the vnode until the last page is released. 776 */ 777 if (object->resident_page_count == 1 && object->type == OBJT_VNODE) 778 vhold((struct vnode *)object->handle); 779 780 /* 781 * Since we are inserting a new and possibly dirty page, 782 * update the object's OBJ_MIGHTBEDIRTY flag. 783 */ 784 if (m->flags & PG_WRITEABLE) 785 vm_object_set_writeable_dirty(object); 786 } 787 788 /* 789 * vm_page_remove: 790 * NOTE: used by device pager as well -wfj 791 * 792 * Removes the given mem entry from the object/offset-page 793 * table and the object page list, but do not invalidate/terminate 794 * the backing store. 795 * 796 * The object and page must be locked. 797 * The underlying pmap entry (if any) is NOT removed here. 798 * This routine may not block. 799 */ 800 void 801 vm_page_remove(vm_page_t m) 802 { 803 vm_object_t object; 804 vm_page_t root; 805 806 if ((m->flags & PG_UNMANAGED) == 0) 807 vm_page_lock_assert(m, MA_OWNED); 808 if ((object = m->object) == NULL) 809 return; 810 VM_OBJECT_LOCK_ASSERT(object, MA_OWNED); 811 if (m->oflags & VPO_BUSY) { 812 m->oflags &= ~VPO_BUSY; 813 vm_page_flash(m); 814 } 815 816 /* 817 * Now remove from the object's list of backed pages. 818 */ 819 if (m != object->root) 820 vm_page_splay(m->pindex, object->root); 821 if (m->left == NULL) 822 root = m->right; 823 else { 824 root = vm_page_splay(m->pindex, m->left); 825 root->right = m->right; 826 } 827 object->root = root; 828 TAILQ_REMOVE(&object->memq, m, listq); 829 830 /* 831 * And show that the object has one fewer resident page. 832 */ 833 object->resident_page_count--; 834 object->generation++; 835 /* 836 * The vnode may now be recycled. 837 */ 838 if (object->resident_page_count == 0 && object->type == OBJT_VNODE) 839 vdrop((struct vnode *)object->handle); 840 841 m->object = NULL; 842 } 843 844 /* 845 * vm_page_lookup: 846 * 847 * Returns the page associated with the object/offset 848 * pair specified; if none is found, NULL is returned. 849 * 850 * The object must be locked. 851 * This routine may not block. 852 * This is a critical path routine 853 */ 854 vm_page_t 855 vm_page_lookup(vm_object_t object, vm_pindex_t pindex) 856 { 857 vm_page_t m; 858 859 VM_OBJECT_LOCK_ASSERT(object, MA_OWNED); 860 if ((m = object->root) != NULL && m->pindex != pindex) { 861 m = vm_page_splay(pindex, m); 862 if ((object->root = m)->pindex != pindex) 863 m = NULL; 864 } 865 return (m); 866 } 867 868 /* 869 * vm_page_rename: 870 * 871 * Move the given memory entry from its 872 * current object to the specified target object/offset. 873 * 874 * The object must be locked. 875 * This routine may not block. 876 * 877 * Note: swap associated with the page must be invalidated by the move. We 878 * have to do this for several reasons: (1) we aren't freeing the 879 * page, (2) we are dirtying the page, (3) the VM system is probably 880 * moving the page from object A to B, and will then later move 881 * the backing store from A to B and we can't have a conflict. 882 * 883 * Note: we *always* dirty the page. It is necessary both for the 884 * fact that we moved it, and because we may be invalidating 885 * swap. If the page is on the cache, we have to deactivate it 886 * or vm_page_dirty() will panic. Dirty pages are not allowed 887 * on the cache. 888 */ 889 void 890 vm_page_rename(vm_page_t m, vm_object_t new_object, vm_pindex_t new_pindex) 891 { 892 893 vm_page_remove(m); 894 vm_page_insert(m, new_object, new_pindex); 895 vm_page_dirty(m); 896 } 897 898 /* 899 * Convert all of the given object's cached pages that have a 900 * pindex within the given range into free pages. If the value 901 * zero is given for "end", then the range's upper bound is 902 * infinity. If the given object is backed by a vnode and it 903 * transitions from having one or more cached pages to none, the 904 * vnode's hold count is reduced. 905 */ 906 void 907 vm_page_cache_free(vm_object_t object, vm_pindex_t start, vm_pindex_t end) 908 { 909 vm_page_t m, m_next; 910 boolean_t empty; 911 912 mtx_lock(&vm_page_queue_free_mtx); 913 if (__predict_false(object->cache == NULL)) { 914 mtx_unlock(&vm_page_queue_free_mtx); 915 return; 916 } 917 m = object->cache = vm_page_splay(start, object->cache); 918 if (m->pindex < start) { 919 if (m->right == NULL) 920 m = NULL; 921 else { 922 m_next = vm_page_splay(start, m->right); 923 m_next->left = m; 924 m->right = NULL; 925 m = object->cache = m_next; 926 } 927 } 928 929 /* 930 * At this point, "m" is either (1) a reference to the page 931 * with the least pindex that is greater than or equal to 932 * "start" or (2) NULL. 933 */ 934 for (; m != NULL && (m->pindex < end || end == 0); m = m_next) { 935 /* 936 * Find "m"'s successor and remove "m" from the 937 * object's cache. 938 */ 939 if (m->right == NULL) { 940 object->cache = m->left; 941 m_next = NULL; 942 } else { 943 m_next = vm_page_splay(start, m->right); 944 m_next->left = m->left; 945 object->cache = m_next; 946 } 947 /* Convert "m" to a free page. */ 948 m->object = NULL; 949 m->valid = 0; 950 /* Clear PG_CACHED and set PG_FREE. */ 951 m->flags ^= PG_CACHED | PG_FREE; 952 KASSERT((m->flags & (PG_CACHED | PG_FREE)) == PG_FREE, 953 ("vm_page_cache_free: page %p has inconsistent flags", m)); 954 cnt.v_cache_count--; 955 cnt.v_free_count++; 956 } 957 empty = object->cache == NULL; 958 mtx_unlock(&vm_page_queue_free_mtx); 959 if (object->type == OBJT_VNODE && empty) 960 vdrop(object->handle); 961 } 962 963 /* 964 * Returns the cached page that is associated with the given 965 * object and offset. If, however, none exists, returns NULL. 966 * 967 * The free page queue must be locked. 968 */ 969 static inline vm_page_t 970 vm_page_cache_lookup(vm_object_t object, vm_pindex_t pindex) 971 { 972 vm_page_t m; 973 974 mtx_assert(&vm_page_queue_free_mtx, MA_OWNED); 975 if ((m = object->cache) != NULL && m->pindex != pindex) { 976 m = vm_page_splay(pindex, m); 977 if ((object->cache = m)->pindex != pindex) 978 m = NULL; 979 } 980 return (m); 981 } 982 983 /* 984 * Remove the given cached page from its containing object's 985 * collection of cached pages. 986 * 987 * The free page queue must be locked. 988 */ 989 void 990 vm_page_cache_remove(vm_page_t m) 991 { 992 vm_object_t object; 993 vm_page_t root; 994 995 mtx_assert(&vm_page_queue_free_mtx, MA_OWNED); 996 KASSERT((m->flags & PG_CACHED) != 0, 997 ("vm_page_cache_remove: page %p is not cached", m)); 998 object = m->object; 999 if (m != object->cache) { 1000 root = vm_page_splay(m->pindex, object->cache); 1001 KASSERT(root == m, 1002 ("vm_page_cache_remove: page %p is not cached in object %p", 1003 m, object)); 1004 } 1005 if (m->left == NULL) 1006 root = m->right; 1007 else if (m->right == NULL) 1008 root = m->left; 1009 else { 1010 root = vm_page_splay(m->pindex, m->left); 1011 root->right = m->right; 1012 } 1013 object->cache = root; 1014 m->object = NULL; 1015 cnt.v_cache_count--; 1016 } 1017 1018 /* 1019 * Transfer all of the cached pages with offset greater than or 1020 * equal to 'offidxstart' from the original object's cache to the 1021 * new object's cache. However, any cached pages with offset 1022 * greater than or equal to the new object's size are kept in the 1023 * original object. Initially, the new object's cache must be 1024 * empty. Offset 'offidxstart' in the original object must 1025 * correspond to offset zero in the new object. 1026 * 1027 * The new object must be locked. 1028 */ 1029 void 1030 vm_page_cache_transfer(vm_object_t orig_object, vm_pindex_t offidxstart, 1031 vm_object_t new_object) 1032 { 1033 vm_page_t m, m_next; 1034 1035 /* 1036 * Insertion into an object's collection of cached pages 1037 * requires the object to be locked. In contrast, removal does 1038 * not. 1039 */ 1040 VM_OBJECT_LOCK_ASSERT(new_object, MA_OWNED); 1041 KASSERT(new_object->cache == NULL, 1042 ("vm_page_cache_transfer: object %p has cached pages", 1043 new_object)); 1044 mtx_lock(&vm_page_queue_free_mtx); 1045 if ((m = orig_object->cache) != NULL) { 1046 /* 1047 * Transfer all of the pages with offset greater than or 1048 * equal to 'offidxstart' from the original object's 1049 * cache to the new object's cache. 1050 */ 1051 m = vm_page_splay(offidxstart, m); 1052 if (m->pindex < offidxstart) { 1053 orig_object->cache = m; 1054 new_object->cache = m->right; 1055 m->right = NULL; 1056 } else { 1057 orig_object->cache = m->left; 1058 new_object->cache = m; 1059 m->left = NULL; 1060 } 1061 while ((m = new_object->cache) != NULL) { 1062 if ((m->pindex - offidxstart) >= new_object->size) { 1063 /* 1064 * Return all of the cached pages with 1065 * offset greater than or equal to the 1066 * new object's size to the original 1067 * object's cache. 1068 */ 1069 new_object->cache = m->left; 1070 m->left = orig_object->cache; 1071 orig_object->cache = m; 1072 break; 1073 } 1074 m_next = vm_page_splay(m->pindex, m->right); 1075 /* Update the page's object and offset. */ 1076 m->object = new_object; 1077 m->pindex -= offidxstart; 1078 if (m_next == NULL) 1079 break; 1080 m->right = NULL; 1081 m_next->left = m; 1082 new_object->cache = m_next; 1083 } 1084 KASSERT(new_object->cache == NULL || 1085 new_object->type == OBJT_SWAP, 1086 ("vm_page_cache_transfer: object %p's type is incompatible" 1087 " with cached pages", new_object)); 1088 } 1089 mtx_unlock(&vm_page_queue_free_mtx); 1090 } 1091 1092 /* 1093 * vm_page_alloc: 1094 * 1095 * Allocate and return a memory cell associated 1096 * with this VM object/offset pair. 1097 * 1098 * page_req classes: 1099 * VM_ALLOC_NORMAL normal process request 1100 * VM_ALLOC_SYSTEM system *really* needs a page 1101 * VM_ALLOC_INTERRUPT interrupt time request 1102 * VM_ALLOC_ZERO zero page 1103 * VM_ALLOC_WIRED wire the allocated page 1104 * VM_ALLOC_NOOBJ page is not associated with a vm object 1105 * VM_ALLOC_NOBUSY do not set the page busy 1106 * VM_ALLOC_IFNOTCACHED return NULL, do not reactivate if the page 1107 * is cached 1108 * 1109 * This routine may not sleep. 1110 */ 1111 vm_page_t 1112 vm_page_alloc(vm_object_t object, vm_pindex_t pindex, int req) 1113 { 1114 struct vnode *vp = NULL; 1115 vm_object_t m_object; 1116 vm_page_t m; 1117 int flags, page_req; 1118 1119 page_req = req & VM_ALLOC_CLASS_MASK; 1120 KASSERT(curthread->td_intr_nesting_level == 0 || 1121 page_req == VM_ALLOC_INTERRUPT, 1122 ("vm_page_alloc(NORMAL|SYSTEM) in interrupt context")); 1123 1124 if ((req & VM_ALLOC_NOOBJ) == 0) { 1125 KASSERT(object != NULL, 1126 ("vm_page_alloc: NULL object.")); 1127 VM_OBJECT_LOCK_ASSERT(object, MA_OWNED); 1128 } 1129 1130 /* 1131 * The pager is allowed to eat deeper into the free page list. 1132 */ 1133 if ((curproc == pageproc) && (page_req != VM_ALLOC_INTERRUPT)) { 1134 page_req = VM_ALLOC_SYSTEM; 1135 }; 1136 1137 mtx_lock(&vm_page_queue_free_mtx); 1138 if (cnt.v_free_count + cnt.v_cache_count > cnt.v_free_reserved || 1139 (page_req == VM_ALLOC_SYSTEM && 1140 cnt.v_free_count + cnt.v_cache_count > cnt.v_interrupt_free_min) || 1141 (page_req == VM_ALLOC_INTERRUPT && 1142 cnt.v_free_count + cnt.v_cache_count > 0)) { 1143 /* 1144 * Allocate from the free queue if the number of free pages 1145 * exceeds the minimum for the request class. 1146 */ 1147 if (object != NULL && 1148 (m = vm_page_cache_lookup(object, pindex)) != NULL) { 1149 if ((req & VM_ALLOC_IFNOTCACHED) != 0) { 1150 mtx_unlock(&vm_page_queue_free_mtx); 1151 return (NULL); 1152 } 1153 if (vm_phys_unfree_page(m)) 1154 vm_phys_set_pool(VM_FREEPOOL_DEFAULT, m, 0); 1155 #if VM_NRESERVLEVEL > 0 1156 else if (!vm_reserv_reactivate_page(m)) 1157 #else 1158 else 1159 #endif 1160 panic("vm_page_alloc: cache page %p is missing" 1161 " from the free queue", m); 1162 } else if ((req & VM_ALLOC_IFCACHED) != 0) { 1163 mtx_unlock(&vm_page_queue_free_mtx); 1164 return (NULL); 1165 #if VM_NRESERVLEVEL > 0 1166 } else if (object == NULL || object->type == OBJT_DEVICE || 1167 object->type == OBJT_SG || 1168 (object->flags & OBJ_COLORED) == 0 || 1169 (m = vm_reserv_alloc_page(object, pindex)) == NULL) { 1170 #else 1171 } else { 1172 #endif 1173 m = vm_phys_alloc_pages(object != NULL ? 1174 VM_FREEPOOL_DEFAULT : VM_FREEPOOL_DIRECT, 0); 1175 #if VM_NRESERVLEVEL > 0 1176 if (m == NULL && vm_reserv_reclaim_inactive()) { 1177 m = vm_phys_alloc_pages(object != NULL ? 1178 VM_FREEPOOL_DEFAULT : VM_FREEPOOL_DIRECT, 1179 0); 1180 } 1181 #endif 1182 } 1183 } else { 1184 /* 1185 * Not allocatable, give up. 1186 */ 1187 mtx_unlock(&vm_page_queue_free_mtx); 1188 atomic_add_int(&vm_pageout_deficit, 1); 1189 pagedaemon_wakeup(); 1190 return (NULL); 1191 } 1192 1193 /* 1194 * At this point we had better have found a good page. 1195 */ 1196 1197 KASSERT(m != NULL, ("vm_page_alloc: missing page")); 1198 KASSERT(m->queue == PQ_NONE, 1199 ("vm_page_alloc: page %p has unexpected queue %d", m, m->queue)); 1200 KASSERT(m->wire_count == 0, ("vm_page_alloc: page %p is wired", m)); 1201 KASSERT(m->hold_count == 0, ("vm_page_alloc: page %p is held", m)); 1202 KASSERT(m->busy == 0, ("vm_page_alloc: page %p is busy", m)); 1203 KASSERT(m->dirty == 0, ("vm_page_alloc: page %p is dirty", m)); 1204 KASSERT(pmap_page_get_memattr(m) == VM_MEMATTR_DEFAULT, 1205 ("vm_page_alloc: page %p has unexpected memattr %d", m, 1206 pmap_page_get_memattr(m))); 1207 if ((m->flags & PG_CACHED) != 0) { 1208 KASSERT(m->valid != 0, 1209 ("vm_page_alloc: cached page %p is invalid", m)); 1210 if (m->object == object && m->pindex == pindex) 1211 cnt.v_reactivated++; 1212 else 1213 m->valid = 0; 1214 m_object = m->object; 1215 vm_page_cache_remove(m); 1216 if (m_object->type == OBJT_VNODE && m_object->cache == NULL) 1217 vp = m_object->handle; 1218 } else { 1219 KASSERT(VM_PAGE_IS_FREE(m), 1220 ("vm_page_alloc: page %p is not free", m)); 1221 KASSERT(m->valid == 0, 1222 ("vm_page_alloc: free page %p is valid", m)); 1223 cnt.v_free_count--; 1224 } 1225 1226 /* 1227 * Initialize structure. Only the PG_ZERO flag is inherited. 1228 */ 1229 flags = 0; 1230 if (m->flags & PG_ZERO) { 1231 vm_page_zero_count--; 1232 if (req & VM_ALLOC_ZERO) 1233 flags = PG_ZERO; 1234 } 1235 if (object == NULL || object->type == OBJT_PHYS) 1236 flags |= PG_UNMANAGED; 1237 m->flags = flags; 1238 if (req & (VM_ALLOC_NOBUSY | VM_ALLOC_NOOBJ)) 1239 m->oflags = 0; 1240 else 1241 m->oflags = VPO_BUSY; 1242 if (req & VM_ALLOC_WIRED) { 1243 atomic_add_int(&cnt.v_wire_count, 1); 1244 m->wire_count = 1; 1245 } 1246 m->act_count = 0; 1247 mtx_unlock(&vm_page_queue_free_mtx); 1248 1249 if (object != NULL) { 1250 /* Ignore device objects; the pager sets "memattr" for them. */ 1251 if (object->memattr != VM_MEMATTR_DEFAULT && 1252 object->type != OBJT_DEVICE && object->type != OBJT_SG) 1253 pmap_page_set_memattr(m, object->memattr); 1254 vm_page_insert(m, object, pindex); 1255 } else 1256 m->pindex = pindex; 1257 1258 /* 1259 * The following call to vdrop() must come after the above call 1260 * to vm_page_insert() in case both affect the same object and 1261 * vnode. Otherwise, the affected vnode's hold count could 1262 * temporarily become zero. 1263 */ 1264 if (vp != NULL) 1265 vdrop(vp); 1266 1267 /* 1268 * Don't wakeup too often - wakeup the pageout daemon when 1269 * we would be nearly out of memory. 1270 */ 1271 if (vm_paging_needed()) 1272 pagedaemon_wakeup(); 1273 1274 return (m); 1275 } 1276 1277 /* 1278 * vm_wait: (also see VM_WAIT macro) 1279 * 1280 * Block until free pages are available for allocation 1281 * - Called in various places before memory allocations. 1282 */ 1283 void 1284 vm_wait(void) 1285 { 1286 1287 mtx_lock(&vm_page_queue_free_mtx); 1288 if (curproc == pageproc) { 1289 vm_pageout_pages_needed = 1; 1290 msleep(&vm_pageout_pages_needed, &vm_page_queue_free_mtx, 1291 PDROP | PSWP, "VMWait", 0); 1292 } else { 1293 if (!vm_pages_needed) { 1294 vm_pages_needed = 1; 1295 wakeup(&vm_pages_needed); 1296 } 1297 msleep(&cnt.v_free_count, &vm_page_queue_free_mtx, PDROP | PVM, 1298 "vmwait", 0); 1299 } 1300 } 1301 1302 /* 1303 * vm_waitpfault: (also see VM_WAITPFAULT macro) 1304 * 1305 * Block until free pages are available for allocation 1306 * - Called only in vm_fault so that processes page faulting 1307 * can be easily tracked. 1308 * - Sleeps at a lower priority than vm_wait() so that vm_wait()ing 1309 * processes will be able to grab memory first. Do not change 1310 * this balance without careful testing first. 1311 */ 1312 void 1313 vm_waitpfault(void) 1314 { 1315 1316 mtx_lock(&vm_page_queue_free_mtx); 1317 if (!vm_pages_needed) { 1318 vm_pages_needed = 1; 1319 wakeup(&vm_pages_needed); 1320 } 1321 msleep(&cnt.v_free_count, &vm_page_queue_free_mtx, PDROP | PUSER, 1322 "pfault", 0); 1323 } 1324 1325 /* 1326 * vm_page_requeue: 1327 * 1328 * If the given page is contained within a page queue, move it to the tail 1329 * of that queue. 1330 * 1331 * The page queues must be locked. 1332 */ 1333 void 1334 vm_page_requeue(vm_page_t m) 1335 { 1336 int queue = VM_PAGE_GETQUEUE(m); 1337 struct vpgqueues *vpq; 1338 1339 if (queue != PQ_NONE) { 1340 vpq = &vm_page_queues[queue]; 1341 TAILQ_REMOVE(&vpq->pl, m, pageq); 1342 TAILQ_INSERT_TAIL(&vpq->pl, m, pageq); 1343 } 1344 } 1345 1346 /* 1347 * vm_page_queue_remove: 1348 * 1349 * Remove the given page from the specified queue. 1350 * 1351 * The page and page queues must be locked. 1352 */ 1353 static __inline void 1354 vm_page_queue_remove(int queue, vm_page_t m) 1355 { 1356 struct vpgqueues *pq; 1357 1358 mtx_assert(&vm_page_queue_mtx, MA_OWNED); 1359 vm_page_lock_assert(m, MA_OWNED); 1360 pq = &vm_page_queues[queue]; 1361 TAILQ_REMOVE(&pq->pl, m, pageq); 1362 (*pq->cnt)--; 1363 } 1364 1365 /* 1366 * vm_pageq_remove: 1367 * 1368 * Remove a page from its queue. 1369 * 1370 * The given page must be locked. 1371 * This routine may not block. 1372 */ 1373 void 1374 vm_pageq_remove(vm_page_t m) 1375 { 1376 int queue = VM_PAGE_GETQUEUE(m); 1377 1378 vm_page_lock_assert(m, MA_OWNED); 1379 if (queue != PQ_NONE) { 1380 vm_page_lock_queues(); 1381 VM_PAGE_SETQUEUE2(m, PQ_NONE); 1382 vm_page_queue_remove(queue, m); 1383 vm_page_unlock_queues(); 1384 } 1385 } 1386 1387 /* 1388 * vm_page_enqueue: 1389 * 1390 * Add the given page to the specified queue. 1391 * 1392 * The page queues must be locked. 1393 */ 1394 static void 1395 vm_page_enqueue(int queue, vm_page_t m) 1396 { 1397 struct vpgqueues *vpq; 1398 1399 vpq = &vm_page_queues[queue]; 1400 VM_PAGE_SETQUEUE2(m, queue); 1401 TAILQ_INSERT_TAIL(&vpq->pl, m, pageq); 1402 ++*vpq->cnt; 1403 } 1404 1405 /* 1406 * vm_page_activate: 1407 * 1408 * Put the specified page on the active list (if appropriate). 1409 * Ensure that act_count is at least ACT_INIT but do not otherwise 1410 * mess with it. 1411 * 1412 * The page must be locked. 1413 * This routine may not block. 1414 */ 1415 void 1416 vm_page_activate(vm_page_t m) 1417 { 1418 int queue; 1419 1420 vm_page_lock_assert(m, MA_OWNED); 1421 if ((queue = VM_PAGE_GETKNOWNQUEUE2(m)) != PQ_ACTIVE) { 1422 if (m->wire_count == 0 && (m->flags & PG_UNMANAGED) == 0) { 1423 if (m->act_count < ACT_INIT) 1424 m->act_count = ACT_INIT; 1425 vm_page_lock_queues(); 1426 if (queue != PQ_NONE) 1427 vm_page_queue_remove(queue, m); 1428 vm_page_enqueue(PQ_ACTIVE, m); 1429 vm_page_unlock_queues(); 1430 } else 1431 KASSERT(queue == PQ_NONE, 1432 ("vm_page_activate: wired page %p is queued", m)); 1433 } else { 1434 if (m->act_count < ACT_INIT) 1435 m->act_count = ACT_INIT; 1436 } 1437 } 1438 1439 /* 1440 * vm_page_free_wakeup: 1441 * 1442 * Helper routine for vm_page_free_toq() and vm_page_cache(). This 1443 * routine is called when a page has been added to the cache or free 1444 * queues. 1445 * 1446 * The page queues must be locked. 1447 * This routine may not block. 1448 */ 1449 static inline void 1450 vm_page_free_wakeup(void) 1451 { 1452 1453 mtx_assert(&vm_page_queue_free_mtx, MA_OWNED); 1454 /* 1455 * if pageout daemon needs pages, then tell it that there are 1456 * some free. 1457 */ 1458 if (vm_pageout_pages_needed && 1459 cnt.v_cache_count + cnt.v_free_count >= cnt.v_pageout_free_min) { 1460 wakeup(&vm_pageout_pages_needed); 1461 vm_pageout_pages_needed = 0; 1462 } 1463 /* 1464 * wakeup processes that are waiting on memory if we hit a 1465 * high water mark. And wakeup scheduler process if we have 1466 * lots of memory. this process will swapin processes. 1467 */ 1468 if (vm_pages_needed && !vm_page_count_min()) { 1469 vm_pages_needed = 0; 1470 wakeup(&cnt.v_free_count); 1471 } 1472 } 1473 1474 /* 1475 * vm_page_free_toq: 1476 * 1477 * Returns the given page to the free list, 1478 * disassociating it with any VM object. 1479 * 1480 * Object and page must be locked prior to entry. 1481 * This routine may not block. 1482 */ 1483 1484 void 1485 vm_page_free_toq(vm_page_t m) 1486 { 1487 1488 if ((m->flags & PG_UNMANAGED) == 0) { 1489 vm_page_lock_assert(m, MA_OWNED); 1490 KASSERT(!pmap_page_is_mapped(m), 1491 ("vm_page_free_toq: freeing mapped page %p", m)); 1492 } 1493 PCPU_INC(cnt.v_tfree); 1494 1495 if (m->busy || VM_PAGE_IS_FREE(m)) { 1496 printf( 1497 "vm_page_free: pindex(%lu), busy(%d), VPO_BUSY(%d), hold(%d)\n", 1498 (u_long)m->pindex, m->busy, (m->oflags & VPO_BUSY) ? 1 : 0, 1499 m->hold_count); 1500 if (VM_PAGE_IS_FREE(m)) 1501 panic("vm_page_free: freeing free page"); 1502 else 1503 panic("vm_page_free: freeing busy page"); 1504 } 1505 1506 /* 1507 * unqueue, then remove page. Note that we cannot destroy 1508 * the page here because we do not want to call the pager's 1509 * callback routine until after we've put the page on the 1510 * appropriate free queue. 1511 */ 1512 if ((m->flags & PG_UNMANAGED) == 0) 1513 vm_pageq_remove(m); 1514 vm_page_remove(m); 1515 1516 /* 1517 * If fictitious remove object association and 1518 * return, otherwise delay object association removal. 1519 */ 1520 if ((m->flags & PG_FICTITIOUS) != 0) { 1521 return; 1522 } 1523 1524 m->valid = 0; 1525 vm_page_undirty(m); 1526 1527 if (m->wire_count != 0) { 1528 if (m->wire_count > 1) { 1529 panic("vm_page_free: invalid wire count (%d), pindex: 0x%lx", 1530 m->wire_count, (long)m->pindex); 1531 } 1532 panic("vm_page_free: freeing wired page"); 1533 } 1534 if (m->hold_count != 0) { 1535 m->flags &= ~PG_ZERO; 1536 vm_page_lock_queues(); 1537 vm_page_enqueue(PQ_HOLD, m); 1538 vm_page_unlock_queues(); 1539 } else { 1540 /* 1541 * Restore the default memory attribute to the page. 1542 */ 1543 if (pmap_page_get_memattr(m) != VM_MEMATTR_DEFAULT) 1544 pmap_page_set_memattr(m, VM_MEMATTR_DEFAULT); 1545 1546 /* 1547 * Insert the page into the physical memory allocator's 1548 * cache/free page queues. 1549 */ 1550 mtx_lock(&vm_page_queue_free_mtx); 1551 m->flags |= PG_FREE; 1552 cnt.v_free_count++; 1553 #if VM_NRESERVLEVEL > 0 1554 if (!vm_reserv_free_page(m)) 1555 #else 1556 if (TRUE) 1557 #endif 1558 vm_phys_free_pages(m, 0); 1559 if ((m->flags & PG_ZERO) != 0) 1560 ++vm_page_zero_count; 1561 else 1562 vm_page_zero_idle_wakeup(); 1563 vm_page_free_wakeup(); 1564 mtx_unlock(&vm_page_queue_free_mtx); 1565 } 1566 } 1567 1568 /* 1569 * vm_page_wire: 1570 * 1571 * Mark this page as wired down by yet 1572 * another map, removing it from paging queues 1573 * as necessary. 1574 * 1575 * The page must be locked. 1576 * This routine may not block. 1577 */ 1578 void 1579 vm_page_wire(vm_page_t m) 1580 { 1581 1582 /* 1583 * Only bump the wire statistics if the page is not already wired, 1584 * and only unqueue the page if it is on some queue (if it is unmanaged 1585 * it is already off the queues). 1586 */ 1587 vm_page_lock_assert(m, MA_OWNED); 1588 if (m->flags & PG_FICTITIOUS) 1589 return; 1590 if (m->wire_count == 0) { 1591 if ((m->flags & PG_UNMANAGED) == 0) 1592 vm_pageq_remove(m); 1593 atomic_add_int(&cnt.v_wire_count, 1); 1594 } 1595 m->wire_count++; 1596 KASSERT(m->wire_count != 0, ("vm_page_wire: wire_count overflow m=%p", m)); 1597 } 1598 1599 /* 1600 * vm_page_unwire: 1601 * 1602 * Release one wiring of this page, potentially 1603 * enabling it to be paged again. 1604 * 1605 * Many pages placed on the inactive queue should actually go 1606 * into the cache, but it is difficult to figure out which. What 1607 * we do instead, if the inactive target is well met, is to put 1608 * clean pages at the head of the inactive queue instead of the tail. 1609 * This will cause them to be moved to the cache more quickly and 1610 * if not actively re-referenced, freed more quickly. If we just 1611 * stick these pages at the end of the inactive queue, heavy filesystem 1612 * meta-data accesses can cause an unnecessary paging load on memory bound 1613 * processes. This optimization causes one-time-use metadata to be 1614 * reused more quickly. 1615 * 1616 * BUT, if we are in a low-memory situation we have no choice but to 1617 * put clean pages on the cache queue. 1618 * 1619 * A number of routines use vm_page_unwire() to guarantee that the page 1620 * will go into either the inactive or active queues, and will NEVER 1621 * be placed in the cache - for example, just after dirtying a page. 1622 * dirty pages in the cache are not allowed. 1623 * 1624 * The page must be locked. 1625 * This routine may not block. 1626 */ 1627 void 1628 vm_page_unwire(vm_page_t m, int activate) 1629 { 1630 1631 if ((m->flags & PG_UNMANAGED) == 0) 1632 vm_page_lock_assert(m, MA_OWNED); 1633 if (m->flags & PG_FICTITIOUS) 1634 return; 1635 if (m->wire_count > 0) { 1636 m->wire_count--; 1637 if (m->wire_count == 0) { 1638 atomic_subtract_int(&cnt.v_wire_count, 1); 1639 if ((m->flags & PG_UNMANAGED) != 0) 1640 return; 1641 vm_page_lock_queues(); 1642 if (activate) 1643 vm_page_enqueue(PQ_ACTIVE, m); 1644 else { 1645 vm_page_flag_clear(m, PG_WINATCFLS); 1646 vm_page_enqueue(PQ_INACTIVE, m); 1647 } 1648 vm_page_unlock_queues(); 1649 } 1650 } else { 1651 panic("vm_page_unwire: invalid wire count: %d", m->wire_count); 1652 } 1653 } 1654 1655 /* 1656 * Move the specified page to the inactive queue. 1657 * 1658 * Normally athead is 0 resulting in LRU operation. athead is set 1659 * to 1 if we want this page to be 'as if it were placed in the cache', 1660 * except without unmapping it from the process address space. 1661 * 1662 * This routine may not block. 1663 */ 1664 static inline void 1665 _vm_page_deactivate(vm_page_t m, int athead) 1666 { 1667 int queue; 1668 1669 vm_page_lock_assert(m, MA_OWNED); 1670 1671 /* 1672 * Ignore if already inactive. 1673 */ 1674 if ((queue = VM_PAGE_GETKNOWNQUEUE2(m)) == PQ_INACTIVE) 1675 return; 1676 if (m->wire_count == 0 && (m->flags & PG_UNMANAGED) == 0) { 1677 vm_page_lock_queues(); 1678 vm_page_flag_clear(m, PG_WINATCFLS); 1679 if (queue != PQ_NONE) 1680 vm_page_queue_remove(queue, m); 1681 if (athead) 1682 TAILQ_INSERT_HEAD(&vm_page_queues[PQ_INACTIVE].pl, m, 1683 pageq); 1684 else 1685 TAILQ_INSERT_TAIL(&vm_page_queues[PQ_INACTIVE].pl, m, 1686 pageq); 1687 VM_PAGE_SETQUEUE2(m, PQ_INACTIVE); 1688 cnt.v_inactive_count++; 1689 vm_page_unlock_queues(); 1690 } 1691 } 1692 1693 /* 1694 * Move the specified page to the inactive queue. 1695 * 1696 * The page must be locked. 1697 */ 1698 void 1699 vm_page_deactivate(vm_page_t m) 1700 { 1701 1702 _vm_page_deactivate(m, 0); 1703 } 1704 1705 /* 1706 * vm_page_try_to_cache: 1707 * 1708 * Returns 0 on failure, 1 on success 1709 */ 1710 int 1711 vm_page_try_to_cache(vm_page_t m) 1712 { 1713 1714 vm_page_lock_assert(m, MA_OWNED); 1715 VM_OBJECT_LOCK_ASSERT(m->object, MA_OWNED); 1716 if (m->dirty || m->hold_count || m->busy || m->wire_count || 1717 (m->oflags & VPO_BUSY) || (m->flags & PG_UNMANAGED)) 1718 return (0); 1719 pmap_remove_all(m); 1720 if (m->dirty) 1721 return (0); 1722 vm_page_cache(m); 1723 return (1); 1724 } 1725 1726 /* 1727 * vm_page_try_to_free() 1728 * 1729 * Attempt to free the page. If we cannot free it, we do nothing. 1730 * 1 is returned on success, 0 on failure. 1731 */ 1732 int 1733 vm_page_try_to_free(vm_page_t m) 1734 { 1735 1736 vm_page_lock_assert(m, MA_OWNED); 1737 if (m->object != NULL) 1738 VM_OBJECT_LOCK_ASSERT(m->object, MA_OWNED); 1739 if (m->dirty || m->hold_count || m->busy || m->wire_count || 1740 (m->oflags & VPO_BUSY) || (m->flags & PG_UNMANAGED)) 1741 return (0); 1742 pmap_remove_all(m); 1743 if (m->dirty) 1744 return (0); 1745 vm_page_free(m); 1746 return (1); 1747 } 1748 1749 /* 1750 * vm_page_cache 1751 * 1752 * Put the specified page onto the page cache queue (if appropriate). 1753 * 1754 * This routine may not block. 1755 */ 1756 void 1757 vm_page_cache(vm_page_t m) 1758 { 1759 vm_object_t object; 1760 vm_page_t root; 1761 1762 vm_page_lock_assert(m, MA_OWNED); 1763 object = m->object; 1764 VM_OBJECT_LOCK_ASSERT(object, MA_OWNED); 1765 if ((m->flags & PG_UNMANAGED) || (m->oflags & VPO_BUSY) || m->busy || 1766 m->hold_count || m->wire_count) 1767 panic("vm_page_cache: attempting to cache busy page"); 1768 pmap_remove_all(m); 1769 if (m->dirty != 0) 1770 panic("vm_page_cache: page %p is dirty", m); 1771 if (m->valid == 0 || object->type == OBJT_DEFAULT || 1772 (object->type == OBJT_SWAP && 1773 !vm_pager_has_page(object, m->pindex, NULL, NULL))) { 1774 /* 1775 * Hypothesis: A cache-elgible page belonging to a 1776 * default object or swap object but without a backing 1777 * store must be zero filled. 1778 */ 1779 vm_page_free(m); 1780 return; 1781 } 1782 KASSERT((m->flags & PG_CACHED) == 0, 1783 ("vm_page_cache: page %p is already cached", m)); 1784 PCPU_INC(cnt.v_tcached); 1785 1786 /* 1787 * Remove the page from the paging queues. 1788 */ 1789 vm_pageq_remove(m); 1790 1791 /* 1792 * Remove the page from the object's collection of resident 1793 * pages. 1794 */ 1795 if (m != object->root) 1796 vm_page_splay(m->pindex, object->root); 1797 if (m->left == NULL) 1798 root = m->right; 1799 else { 1800 root = vm_page_splay(m->pindex, m->left); 1801 root->right = m->right; 1802 } 1803 object->root = root; 1804 TAILQ_REMOVE(&object->memq, m, listq); 1805 object->resident_page_count--; 1806 object->generation++; 1807 1808 /* 1809 * Restore the default memory attribute to the page. 1810 */ 1811 if (pmap_page_get_memattr(m) != VM_MEMATTR_DEFAULT) 1812 pmap_page_set_memattr(m, VM_MEMATTR_DEFAULT); 1813 1814 /* 1815 * Insert the page into the object's collection of cached pages 1816 * and the physical memory allocator's cache/free page queues. 1817 */ 1818 m->flags &= ~PG_ZERO; 1819 mtx_lock(&vm_page_queue_free_mtx); 1820 m->flags |= PG_CACHED; 1821 cnt.v_cache_count++; 1822 root = object->cache; 1823 if (root == NULL) { 1824 m->left = NULL; 1825 m->right = NULL; 1826 } else { 1827 root = vm_page_splay(m->pindex, root); 1828 if (m->pindex < root->pindex) { 1829 m->left = root->left; 1830 m->right = root; 1831 root->left = NULL; 1832 } else if (__predict_false(m->pindex == root->pindex)) 1833 panic("vm_page_cache: offset already cached"); 1834 else { 1835 m->right = root->right; 1836 m->left = root; 1837 root->right = NULL; 1838 } 1839 } 1840 object->cache = m; 1841 #if VM_NRESERVLEVEL > 0 1842 if (!vm_reserv_free_page(m)) { 1843 #else 1844 if (TRUE) { 1845 #endif 1846 vm_phys_set_pool(VM_FREEPOOL_CACHE, m, 0); 1847 vm_phys_free_pages(m, 0); 1848 } 1849 vm_page_free_wakeup(); 1850 mtx_unlock(&vm_page_queue_free_mtx); 1851 1852 /* 1853 * Increment the vnode's hold count if this is the object's only 1854 * cached page. Decrement the vnode's hold count if this was 1855 * the object's only resident page. 1856 */ 1857 if (object->type == OBJT_VNODE) { 1858 if (root == NULL && object->resident_page_count != 0) 1859 vhold(object->handle); 1860 else if (root != NULL && object->resident_page_count == 0) 1861 vdrop(object->handle); 1862 } 1863 } 1864 1865 /* 1866 * vm_page_dontneed 1867 * 1868 * Cache, deactivate, or do nothing as appropriate. This routine 1869 * is typically used by madvise() MADV_DONTNEED. 1870 * 1871 * Generally speaking we want to move the page into the cache so 1872 * it gets reused quickly. However, this can result in a silly syndrome 1873 * due to the page recycling too quickly. Small objects will not be 1874 * fully cached. On the otherhand, if we move the page to the inactive 1875 * queue we wind up with a problem whereby very large objects 1876 * unnecessarily blow away our inactive and cache queues. 1877 * 1878 * The solution is to move the pages based on a fixed weighting. We 1879 * either leave them alone, deactivate them, or move them to the cache, 1880 * where moving them to the cache has the highest weighting. 1881 * By forcing some pages into other queues we eventually force the 1882 * system to balance the queues, potentially recovering other unrelated 1883 * space from active. The idea is to not force this to happen too 1884 * often. 1885 */ 1886 void 1887 vm_page_dontneed(vm_page_t m) 1888 { 1889 int dnw; 1890 int head; 1891 1892 vm_page_lock_assert(m, MA_OWNED); 1893 VM_OBJECT_LOCK_ASSERT(m->object, MA_OWNED); 1894 dnw = PCPU_GET(dnweight); 1895 PCPU_INC(dnweight); 1896 1897 /* 1898 * Occasionally leave the page alone. 1899 */ 1900 if ((dnw & 0x01F0) == 0 || 1901 VM_PAGE_INQUEUE2(m, PQ_INACTIVE)) { 1902 if (m->act_count >= ACT_INIT) 1903 --m->act_count; 1904 return; 1905 } 1906 1907 /* 1908 * Clear any references to the page. Otherwise, the page daemon will 1909 * immediately reactivate the page. 1910 * 1911 * Perform the pmap_clear_reference() first. Otherwise, a concurrent 1912 * pmap operation, such as pmap_remove(), could clear a reference in 1913 * the pmap and set PG_REFERENCED on the page before the 1914 * pmap_clear_reference() had completed. Consequently, the page would 1915 * appear referenced based upon an old reference that occurred before 1916 * this function ran. 1917 */ 1918 pmap_clear_reference(m); 1919 vm_page_lock_queues(); 1920 vm_page_flag_clear(m, PG_REFERENCED); 1921 vm_page_unlock_queues(); 1922 1923 if (m->dirty == 0 && pmap_is_modified(m)) 1924 vm_page_dirty(m); 1925 1926 if (m->dirty || (dnw & 0x0070) == 0) { 1927 /* 1928 * Deactivate the page 3 times out of 32. 1929 */ 1930 head = 0; 1931 } else { 1932 /* 1933 * Cache the page 28 times out of every 32. Note that 1934 * the page is deactivated instead of cached, but placed 1935 * at the head of the queue instead of the tail. 1936 */ 1937 head = 1; 1938 } 1939 _vm_page_deactivate(m, head); 1940 } 1941 1942 /* 1943 * Grab a page, waiting until we are waken up due to the page 1944 * changing state. We keep on waiting, if the page continues 1945 * to be in the object. If the page doesn't exist, first allocate it 1946 * and then conditionally zero it. 1947 * 1948 * This routine may block. 1949 */ 1950 vm_page_t 1951 vm_page_grab(vm_object_t object, vm_pindex_t pindex, int allocflags) 1952 { 1953 vm_page_t m; 1954 1955 VM_OBJECT_LOCK_ASSERT(object, MA_OWNED); 1956 retrylookup: 1957 if ((m = vm_page_lookup(object, pindex)) != NULL) { 1958 if ((m->oflags & VPO_BUSY) != 0 || m->busy != 0) { 1959 if ((allocflags & VM_ALLOC_RETRY) != 0) { 1960 /* 1961 * Reference the page before unlocking and 1962 * sleeping so that the page daemon is less 1963 * likely to reclaim it. 1964 */ 1965 vm_page_lock_queues(); 1966 vm_page_flag_set(m, PG_REFERENCED); 1967 } 1968 vm_page_sleep(m, "pgrbwt"); 1969 if ((allocflags & VM_ALLOC_RETRY) == 0) 1970 return (NULL); 1971 goto retrylookup; 1972 } else { 1973 if ((allocflags & VM_ALLOC_WIRED) != 0) { 1974 vm_page_lock(m); 1975 vm_page_wire(m); 1976 vm_page_unlock(m); 1977 } 1978 if ((allocflags & VM_ALLOC_NOBUSY) == 0) 1979 vm_page_busy(m); 1980 return (m); 1981 } 1982 } 1983 m = vm_page_alloc(object, pindex, allocflags & ~VM_ALLOC_RETRY); 1984 if (m == NULL) { 1985 VM_OBJECT_UNLOCK(object); 1986 VM_WAIT; 1987 VM_OBJECT_LOCK(object); 1988 if ((allocflags & VM_ALLOC_RETRY) == 0) 1989 return (NULL); 1990 goto retrylookup; 1991 } else if (m->valid != 0) 1992 return (m); 1993 if (allocflags & VM_ALLOC_ZERO && (m->flags & PG_ZERO) == 0) 1994 pmap_zero_page(m); 1995 return (m); 1996 } 1997 1998 /* 1999 * Mapping function for valid bits or for dirty bits in 2000 * a page. May not block. 2001 * 2002 * Inputs are required to range within a page. 2003 */ 2004 int 2005 vm_page_bits(int base, int size) 2006 { 2007 int first_bit; 2008 int last_bit; 2009 2010 KASSERT( 2011 base + size <= PAGE_SIZE, 2012 ("vm_page_bits: illegal base/size %d/%d", base, size) 2013 ); 2014 2015 if (size == 0) /* handle degenerate case */ 2016 return (0); 2017 2018 first_bit = base >> DEV_BSHIFT; 2019 last_bit = (base + size - 1) >> DEV_BSHIFT; 2020 2021 return ((2 << last_bit) - (1 << first_bit)); 2022 } 2023 2024 /* 2025 * vm_page_set_valid: 2026 * 2027 * Sets portions of a page valid. The arguments are expected 2028 * to be DEV_BSIZE aligned but if they aren't the bitmap is inclusive 2029 * of any partial chunks touched by the range. The invalid portion of 2030 * such chunks will be zeroed. 2031 * 2032 * (base + size) must be less then or equal to PAGE_SIZE. 2033 */ 2034 void 2035 vm_page_set_valid(vm_page_t m, int base, int size) 2036 { 2037 int endoff, frag; 2038 2039 VM_OBJECT_LOCK_ASSERT(m->object, MA_OWNED); 2040 if (size == 0) /* handle degenerate case */ 2041 return; 2042 2043 /* 2044 * If the base is not DEV_BSIZE aligned and the valid 2045 * bit is clear, we have to zero out a portion of the 2046 * first block. 2047 */ 2048 if ((frag = base & ~(DEV_BSIZE - 1)) != base && 2049 (m->valid & (1 << (base >> DEV_BSHIFT))) == 0) 2050 pmap_zero_page_area(m, frag, base - frag); 2051 2052 /* 2053 * If the ending offset is not DEV_BSIZE aligned and the 2054 * valid bit is clear, we have to zero out a portion of 2055 * the last block. 2056 */ 2057 endoff = base + size; 2058 if ((frag = endoff & ~(DEV_BSIZE - 1)) != endoff && 2059 (m->valid & (1 << (endoff >> DEV_BSHIFT))) == 0) 2060 pmap_zero_page_area(m, endoff, 2061 DEV_BSIZE - (endoff & (DEV_BSIZE - 1))); 2062 2063 /* 2064 * Assert that no previously invalid block that is now being validated 2065 * is already dirty. 2066 */ 2067 KASSERT((~m->valid & vm_page_bits(base, size) & m->dirty) == 0, 2068 ("vm_page_set_valid: page %p is dirty", m)); 2069 2070 /* 2071 * Set valid bits inclusive of any overlap. 2072 */ 2073 m->valid |= vm_page_bits(base, size); 2074 } 2075 2076 /* 2077 * Clear the given bits from the specified page's dirty field. 2078 */ 2079 static __inline void 2080 vm_page_clear_dirty_mask(vm_page_t m, int pagebits) 2081 { 2082 2083 /* 2084 * If the object is locked and the page is neither VPO_BUSY nor 2085 * PG_WRITEABLE, then the page's dirty field cannot possibly be 2086 * modified by a concurrent pmap operation. 2087 */ 2088 VM_OBJECT_LOCK_ASSERT(m->object, MA_OWNED); 2089 if ((m->oflags & VPO_BUSY) == 0 && (m->flags & PG_WRITEABLE) == 0) 2090 m->dirty &= ~pagebits; 2091 else { 2092 vm_page_lock_queues(); 2093 m->dirty &= ~pagebits; 2094 vm_page_unlock_queues(); 2095 } 2096 } 2097 2098 /* 2099 * vm_page_set_validclean: 2100 * 2101 * Sets portions of a page valid and clean. The arguments are expected 2102 * to be DEV_BSIZE aligned but if they aren't the bitmap is inclusive 2103 * of any partial chunks touched by the range. The invalid portion of 2104 * such chunks will be zero'd. 2105 * 2106 * This routine may not block. 2107 * 2108 * (base + size) must be less then or equal to PAGE_SIZE. 2109 */ 2110 void 2111 vm_page_set_validclean(vm_page_t m, int base, int size) 2112 { 2113 u_int oldvalid; 2114 int endoff, frag, pagebits; 2115 2116 VM_OBJECT_LOCK_ASSERT(m->object, MA_OWNED); 2117 if (size == 0) /* handle degenerate case */ 2118 return; 2119 2120 /* 2121 * If the base is not DEV_BSIZE aligned and the valid 2122 * bit is clear, we have to zero out a portion of the 2123 * first block. 2124 */ 2125 if ((frag = base & ~(DEV_BSIZE - 1)) != base && 2126 (m->valid & (1 << (base >> DEV_BSHIFT))) == 0) 2127 pmap_zero_page_area(m, frag, base - frag); 2128 2129 /* 2130 * If the ending offset is not DEV_BSIZE aligned and the 2131 * valid bit is clear, we have to zero out a portion of 2132 * the last block. 2133 */ 2134 endoff = base + size; 2135 if ((frag = endoff & ~(DEV_BSIZE - 1)) != endoff && 2136 (m->valid & (1 << (endoff >> DEV_BSHIFT))) == 0) 2137 pmap_zero_page_area(m, endoff, 2138 DEV_BSIZE - (endoff & (DEV_BSIZE - 1))); 2139 2140 /* 2141 * Set valid, clear dirty bits. If validating the entire 2142 * page we can safely clear the pmap modify bit. We also 2143 * use this opportunity to clear the VPO_NOSYNC flag. If a process 2144 * takes a write fault on a MAP_NOSYNC memory area the flag will 2145 * be set again. 2146 * 2147 * We set valid bits inclusive of any overlap, but we can only 2148 * clear dirty bits for DEV_BSIZE chunks that are fully within 2149 * the range. 2150 */ 2151 oldvalid = m->valid; 2152 pagebits = vm_page_bits(base, size); 2153 m->valid |= pagebits; 2154 #if 0 /* NOT YET */ 2155 if ((frag = base & (DEV_BSIZE - 1)) != 0) { 2156 frag = DEV_BSIZE - frag; 2157 base += frag; 2158 size -= frag; 2159 if (size < 0) 2160 size = 0; 2161 } 2162 pagebits = vm_page_bits(base, size & (DEV_BSIZE - 1)); 2163 #endif 2164 if (base == 0 && size == PAGE_SIZE) { 2165 /* 2166 * The page can only be modified within the pmap if it is 2167 * mapped, and it can only be mapped if it was previously 2168 * fully valid. 2169 */ 2170 if (oldvalid == VM_PAGE_BITS_ALL) 2171 /* 2172 * Perform the pmap_clear_modify() first. Otherwise, 2173 * a concurrent pmap operation, such as 2174 * pmap_protect(), could clear a modification in the 2175 * pmap and set the dirty field on the page before 2176 * pmap_clear_modify() had begun and after the dirty 2177 * field was cleared here. 2178 */ 2179 pmap_clear_modify(m); 2180 m->dirty = 0; 2181 m->oflags &= ~VPO_NOSYNC; 2182 } else if (oldvalid != VM_PAGE_BITS_ALL) 2183 m->dirty &= ~pagebits; 2184 else 2185 vm_page_clear_dirty_mask(m, pagebits); 2186 } 2187 2188 void 2189 vm_page_clear_dirty(vm_page_t m, int base, int size) 2190 { 2191 2192 vm_page_clear_dirty_mask(m, vm_page_bits(base, size)); 2193 } 2194 2195 /* 2196 * vm_page_set_invalid: 2197 * 2198 * Invalidates DEV_BSIZE'd chunks within a page. Both the 2199 * valid and dirty bits for the effected areas are cleared. 2200 * 2201 * May not block. 2202 */ 2203 void 2204 vm_page_set_invalid(vm_page_t m, int base, int size) 2205 { 2206 int bits; 2207 2208 VM_OBJECT_LOCK_ASSERT(m->object, MA_OWNED); 2209 KASSERT((m->oflags & VPO_BUSY) == 0, 2210 ("vm_page_set_invalid: page %p is busy", m)); 2211 bits = vm_page_bits(base, size); 2212 if (m->valid == VM_PAGE_BITS_ALL && bits != 0) 2213 pmap_remove_all(m); 2214 KASSERT(!pmap_page_is_mapped(m), 2215 ("vm_page_set_invalid: page %p is mapped", m)); 2216 m->valid &= ~bits; 2217 m->dirty &= ~bits; 2218 m->object->generation++; 2219 } 2220 2221 /* 2222 * vm_page_zero_invalid() 2223 * 2224 * The kernel assumes that the invalid portions of a page contain 2225 * garbage, but such pages can be mapped into memory by user code. 2226 * When this occurs, we must zero out the non-valid portions of the 2227 * page so user code sees what it expects. 2228 * 2229 * Pages are most often semi-valid when the end of a file is mapped 2230 * into memory and the file's size is not page aligned. 2231 */ 2232 void 2233 vm_page_zero_invalid(vm_page_t m, boolean_t setvalid) 2234 { 2235 int b; 2236 int i; 2237 2238 VM_OBJECT_LOCK_ASSERT(m->object, MA_OWNED); 2239 /* 2240 * Scan the valid bits looking for invalid sections that 2241 * must be zerod. Invalid sub-DEV_BSIZE'd areas ( where the 2242 * valid bit may be set ) have already been zerod by 2243 * vm_page_set_validclean(). 2244 */ 2245 for (b = i = 0; i <= PAGE_SIZE / DEV_BSIZE; ++i) { 2246 if (i == (PAGE_SIZE / DEV_BSIZE) || 2247 (m->valid & (1 << i)) 2248 ) { 2249 if (i > b) { 2250 pmap_zero_page_area(m, 2251 b << DEV_BSHIFT, (i - b) << DEV_BSHIFT); 2252 } 2253 b = i + 1; 2254 } 2255 } 2256 2257 /* 2258 * setvalid is TRUE when we can safely set the zero'd areas 2259 * as being valid. We can do this if there are no cache consistancy 2260 * issues. e.g. it is ok to do with UFS, but not ok to do with NFS. 2261 */ 2262 if (setvalid) 2263 m->valid = VM_PAGE_BITS_ALL; 2264 } 2265 2266 /* 2267 * vm_page_is_valid: 2268 * 2269 * Is (partial) page valid? Note that the case where size == 0 2270 * will return FALSE in the degenerate case where the page is 2271 * entirely invalid, and TRUE otherwise. 2272 * 2273 * May not block. 2274 */ 2275 int 2276 vm_page_is_valid(vm_page_t m, int base, int size) 2277 { 2278 int bits = vm_page_bits(base, size); 2279 2280 VM_OBJECT_LOCK_ASSERT(m->object, MA_OWNED); 2281 if (m->valid && ((m->valid & bits) == bits)) 2282 return 1; 2283 else 2284 return 0; 2285 } 2286 2287 /* 2288 * update dirty bits from pmap/mmu. May not block. 2289 */ 2290 void 2291 vm_page_test_dirty(vm_page_t m) 2292 { 2293 2294 VM_OBJECT_LOCK_ASSERT(m->object, MA_OWNED); 2295 if (m->dirty != VM_PAGE_BITS_ALL && pmap_is_modified(m)) 2296 vm_page_dirty(m); 2297 } 2298 2299 int so_zerocp_fullpage = 0; 2300 2301 /* 2302 * Replace the given page with a copy. The copied page assumes 2303 * the portion of the given page's "wire_count" that is not the 2304 * responsibility of this copy-on-write mechanism. 2305 * 2306 * The object containing the given page must have a non-zero 2307 * paging-in-progress count and be locked. 2308 */ 2309 void 2310 vm_page_cowfault(vm_page_t m) 2311 { 2312 vm_page_t mnew; 2313 vm_object_t object; 2314 vm_pindex_t pindex; 2315 2316 mtx_assert(&vm_page_queue_mtx, MA_NOTOWNED); 2317 vm_page_lock_assert(m, MA_OWNED); 2318 object = m->object; 2319 VM_OBJECT_LOCK_ASSERT(object, MA_OWNED); 2320 KASSERT(object->paging_in_progress != 0, 2321 ("vm_page_cowfault: object %p's paging-in-progress count is zero.", 2322 object)); 2323 pindex = m->pindex; 2324 2325 retry_alloc: 2326 pmap_remove_all(m); 2327 vm_page_remove(m); 2328 mnew = vm_page_alloc(object, pindex, VM_ALLOC_NORMAL | VM_ALLOC_NOBUSY); 2329 if (mnew == NULL) { 2330 vm_page_insert(m, object, pindex); 2331 vm_page_unlock(m); 2332 VM_OBJECT_UNLOCK(object); 2333 VM_WAIT; 2334 VM_OBJECT_LOCK(object); 2335 if (m == vm_page_lookup(object, pindex)) { 2336 vm_page_lock(m); 2337 goto retry_alloc; 2338 } else { 2339 /* 2340 * Page disappeared during the wait. 2341 */ 2342 return; 2343 } 2344 } 2345 2346 if (m->cow == 0) { 2347 /* 2348 * check to see if we raced with an xmit complete when 2349 * waiting to allocate a page. If so, put things back 2350 * the way they were 2351 */ 2352 vm_page_unlock(m); 2353 vm_page_lock(mnew); 2354 vm_page_free(mnew); 2355 vm_page_unlock(mnew); 2356 vm_page_insert(m, object, pindex); 2357 } else { /* clear COW & copy page */ 2358 if (!so_zerocp_fullpage) 2359 pmap_copy_page(m, mnew); 2360 mnew->valid = VM_PAGE_BITS_ALL; 2361 vm_page_dirty(mnew); 2362 mnew->wire_count = m->wire_count - m->cow; 2363 m->wire_count = m->cow; 2364 vm_page_unlock(m); 2365 } 2366 } 2367 2368 void 2369 vm_page_cowclear(vm_page_t m) 2370 { 2371 2372 vm_page_lock_assert(m, MA_OWNED); 2373 if (m->cow) { 2374 m->cow--; 2375 /* 2376 * let vm_fault add back write permission lazily 2377 */ 2378 } 2379 /* 2380 * sf_buf_free() will free the page, so we needn't do it here 2381 */ 2382 } 2383 2384 int 2385 vm_page_cowsetup(vm_page_t m) 2386 { 2387 2388 vm_page_lock_assert(m, MA_OWNED); 2389 if ((m->flags & (PG_FICTITIOUS | PG_UNMANAGED)) != 0 || 2390 m->cow == USHRT_MAX - 1 || !VM_OBJECT_TRYLOCK(m->object)) 2391 return (EBUSY); 2392 m->cow++; 2393 pmap_remove_write(m); 2394 VM_OBJECT_UNLOCK(m->object); 2395 return (0); 2396 } 2397 2398 #include "opt_ddb.h" 2399 #ifdef DDB 2400 #include <sys/kernel.h> 2401 2402 #include <ddb/ddb.h> 2403 2404 DB_SHOW_COMMAND(page, vm_page_print_page_info) 2405 { 2406 db_printf("cnt.v_free_count: %d\n", cnt.v_free_count); 2407 db_printf("cnt.v_cache_count: %d\n", cnt.v_cache_count); 2408 db_printf("cnt.v_inactive_count: %d\n", cnt.v_inactive_count); 2409 db_printf("cnt.v_active_count: %d\n", cnt.v_active_count); 2410 db_printf("cnt.v_wire_count: %d\n", cnt.v_wire_count); 2411 db_printf("cnt.v_free_reserved: %d\n", cnt.v_free_reserved); 2412 db_printf("cnt.v_free_min: %d\n", cnt.v_free_min); 2413 db_printf("cnt.v_free_target: %d\n", cnt.v_free_target); 2414 db_printf("cnt.v_cache_min: %d\n", cnt.v_cache_min); 2415 db_printf("cnt.v_inactive_target: %d\n", cnt.v_inactive_target); 2416 } 2417 2418 DB_SHOW_COMMAND(pageq, vm_page_print_pageq_info) 2419 { 2420 2421 db_printf("PQ_FREE:"); 2422 db_printf(" %d", cnt.v_free_count); 2423 db_printf("\n"); 2424 2425 db_printf("PQ_CACHE:"); 2426 db_printf(" %d", cnt.v_cache_count); 2427 db_printf("\n"); 2428 2429 db_printf("PQ_ACTIVE: %d, PQ_INACTIVE: %d\n", 2430 *vm_page_queues[PQ_ACTIVE].cnt, 2431 *vm_page_queues[PQ_INACTIVE].cnt); 2432 } 2433 #endif /* DDB */ 2434