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 /* 490 * For a managed page, the PG_WRITEABLE flag can be set only if 491 * the page is VPO_BUSY. Currently this flag is only set by 492 * pmap_enter(). 493 */ 494 KASSERT((bits & PG_WRITEABLE) == 0 || 495 (m->flags & (PG_UNMANAGED | PG_FICTITIOUS)) != 0 || 496 (m->oflags & VPO_BUSY) != 0, ("PG_WRITEABLE and !VPO_BUSY")); 497 m->flags |= bits; 498 } 499 500 void 501 vm_page_flag_clear(vm_page_t m, unsigned short bits) 502 { 503 504 mtx_assert(&vm_page_queue_mtx, MA_OWNED); 505 m->flags &= ~bits; 506 } 507 508 void 509 vm_page_busy(vm_page_t m) 510 { 511 512 VM_OBJECT_LOCK_ASSERT(m->object, MA_OWNED); 513 KASSERT((m->oflags & VPO_BUSY) == 0, 514 ("vm_page_busy: page already busy!!!")); 515 m->oflags |= VPO_BUSY; 516 } 517 518 /* 519 * vm_page_flash: 520 * 521 * wakeup anyone waiting for the page. 522 */ 523 void 524 vm_page_flash(vm_page_t m) 525 { 526 527 VM_OBJECT_LOCK_ASSERT(m->object, MA_OWNED); 528 if (m->oflags & VPO_WANTED) { 529 m->oflags &= ~VPO_WANTED; 530 wakeup(m); 531 } 532 } 533 534 /* 535 * vm_page_wakeup: 536 * 537 * clear the VPO_BUSY flag and wakeup anyone waiting for the 538 * page. 539 * 540 */ 541 void 542 vm_page_wakeup(vm_page_t m) 543 { 544 545 VM_OBJECT_LOCK_ASSERT(m->object, MA_OWNED); 546 KASSERT(m->oflags & VPO_BUSY, ("vm_page_wakeup: page not busy!!!")); 547 m->oflags &= ~VPO_BUSY; 548 vm_page_flash(m); 549 } 550 551 void 552 vm_page_io_start(vm_page_t m) 553 { 554 555 VM_OBJECT_LOCK_ASSERT(m->object, MA_OWNED); 556 m->busy++; 557 } 558 559 void 560 vm_page_io_finish(vm_page_t m) 561 { 562 563 VM_OBJECT_LOCK_ASSERT(m->object, MA_OWNED); 564 m->busy--; 565 if (m->busy == 0) 566 vm_page_flash(m); 567 } 568 569 /* 570 * Keep page from being freed by the page daemon 571 * much of the same effect as wiring, except much lower 572 * overhead and should be used only for *very* temporary 573 * holding ("wiring"). 574 */ 575 void 576 vm_page_hold(vm_page_t mem) 577 { 578 579 vm_page_lock_assert(mem, MA_OWNED); 580 mem->hold_count++; 581 } 582 583 void 584 vm_page_unhold(vm_page_t mem) 585 { 586 587 vm_page_lock_assert(mem, MA_OWNED); 588 --mem->hold_count; 589 KASSERT(mem->hold_count >= 0, ("vm_page_unhold: hold count < 0!!!")); 590 if (mem->hold_count == 0 && VM_PAGE_INQUEUE2(mem, PQ_HOLD)) 591 vm_page_free_toq(mem); 592 } 593 594 /* 595 * vm_page_free: 596 * 597 * Free a page. 598 */ 599 void 600 vm_page_free(vm_page_t m) 601 { 602 603 m->flags &= ~PG_ZERO; 604 vm_page_free_toq(m); 605 } 606 607 /* 608 * vm_page_free_zero: 609 * 610 * Free a page to the zerod-pages queue 611 */ 612 void 613 vm_page_free_zero(vm_page_t m) 614 { 615 616 m->flags |= PG_ZERO; 617 vm_page_free_toq(m); 618 } 619 620 /* 621 * vm_page_sleep: 622 * 623 * Sleep and release the page and page queues locks. 624 * 625 * The object containing the given page must be locked. 626 */ 627 void 628 vm_page_sleep(vm_page_t m, const char *msg) 629 { 630 631 VM_OBJECT_LOCK_ASSERT(m->object, MA_OWNED); 632 if (mtx_owned(&vm_page_queue_mtx)) 633 vm_page_unlock_queues(); 634 if (mtx_owned(vm_page_lockptr(m))) 635 vm_page_unlock(m); 636 637 /* 638 * It's possible that while we sleep, the page will get 639 * unbusied and freed. If we are holding the object 640 * lock, we will assume we hold a reference to the object 641 * such that even if m->object changes, we can re-lock 642 * it. 643 */ 644 m->oflags |= VPO_WANTED; 645 msleep(m, VM_OBJECT_MTX(m->object), PVM, msg, 0); 646 } 647 648 /* 649 * vm_page_dirty: 650 * 651 * make page all dirty 652 */ 653 void 654 vm_page_dirty(vm_page_t m) 655 { 656 657 KASSERT((m->flags & PG_CACHED) == 0, 658 ("vm_page_dirty: page in cache!")); 659 KASSERT(!VM_PAGE_IS_FREE(m), 660 ("vm_page_dirty: page is free!")); 661 KASSERT(m->valid == VM_PAGE_BITS_ALL, 662 ("vm_page_dirty: page is invalid!")); 663 m->dirty = VM_PAGE_BITS_ALL; 664 } 665 666 /* 667 * vm_page_splay: 668 * 669 * Implements Sleator and Tarjan's top-down splay algorithm. Returns 670 * the vm_page containing the given pindex. If, however, that 671 * pindex is not found in the vm_object, returns a vm_page that is 672 * adjacent to the pindex, coming before or after it. 673 */ 674 vm_page_t 675 vm_page_splay(vm_pindex_t pindex, vm_page_t root) 676 { 677 struct vm_page dummy; 678 vm_page_t lefttreemax, righttreemin, y; 679 680 if (root == NULL) 681 return (root); 682 lefttreemax = righttreemin = &dummy; 683 for (;; root = y) { 684 if (pindex < root->pindex) { 685 if ((y = root->left) == NULL) 686 break; 687 if (pindex < y->pindex) { 688 /* Rotate right. */ 689 root->left = y->right; 690 y->right = root; 691 root = y; 692 if ((y = root->left) == NULL) 693 break; 694 } 695 /* Link into the new root's right tree. */ 696 righttreemin->left = root; 697 righttreemin = root; 698 } else if (pindex > root->pindex) { 699 if ((y = root->right) == NULL) 700 break; 701 if (pindex > y->pindex) { 702 /* Rotate left. */ 703 root->right = y->left; 704 y->left = root; 705 root = y; 706 if ((y = root->right) == NULL) 707 break; 708 } 709 /* Link into the new root's left tree. */ 710 lefttreemax->right = root; 711 lefttreemax = root; 712 } else 713 break; 714 } 715 /* Assemble the new root. */ 716 lefttreemax->right = root->left; 717 righttreemin->left = root->right; 718 root->left = dummy.right; 719 root->right = dummy.left; 720 return (root); 721 } 722 723 /* 724 * vm_page_insert: [ internal use only ] 725 * 726 * Inserts the given mem entry into the object and object list. 727 * 728 * The pagetables are not updated but will presumably fault the page 729 * in if necessary, or if a kernel page the caller will at some point 730 * enter the page into the kernel's pmap. We are not allowed to block 731 * here so we *can't* do this anyway. 732 * 733 * The object and page must be locked. 734 * This routine may not block. 735 */ 736 void 737 vm_page_insert(vm_page_t m, vm_object_t object, vm_pindex_t pindex) 738 { 739 vm_page_t root; 740 741 VM_OBJECT_LOCK_ASSERT(object, MA_OWNED); 742 if (m->object != NULL) 743 panic("vm_page_insert: page already inserted"); 744 745 /* 746 * Record the object/offset pair in this page 747 */ 748 m->object = object; 749 m->pindex = pindex; 750 751 /* 752 * Now link into the object's ordered list of backed pages. 753 */ 754 root = object->root; 755 if (root == NULL) { 756 m->left = NULL; 757 m->right = NULL; 758 TAILQ_INSERT_TAIL(&object->memq, m, listq); 759 } else { 760 root = vm_page_splay(pindex, root); 761 if (pindex < root->pindex) { 762 m->left = root->left; 763 m->right = root; 764 root->left = NULL; 765 TAILQ_INSERT_BEFORE(root, m, listq); 766 } else if (pindex == root->pindex) 767 panic("vm_page_insert: offset already allocated"); 768 else { 769 m->right = root->right; 770 m->left = root; 771 root->right = NULL; 772 TAILQ_INSERT_AFTER(&object->memq, root, m, listq); 773 } 774 } 775 object->root = m; 776 object->generation++; 777 778 /* 779 * show that the object has one more resident page. 780 */ 781 object->resident_page_count++; 782 /* 783 * Hold the vnode until the last page is released. 784 */ 785 if (object->resident_page_count == 1 && object->type == OBJT_VNODE) 786 vhold((struct vnode *)object->handle); 787 788 /* 789 * Since we are inserting a new and possibly dirty page, 790 * update the object's OBJ_MIGHTBEDIRTY flag. 791 */ 792 if (m->flags & PG_WRITEABLE) 793 vm_object_set_writeable_dirty(object); 794 } 795 796 /* 797 * vm_page_remove: 798 * NOTE: used by device pager as well -wfj 799 * 800 * Removes the given mem entry from the object/offset-page 801 * table and the object page list, but do not invalidate/terminate 802 * the backing store. 803 * 804 * The object and page must be locked. 805 * The underlying pmap entry (if any) is NOT removed here. 806 * This routine may not block. 807 */ 808 void 809 vm_page_remove(vm_page_t m) 810 { 811 vm_object_t object; 812 vm_page_t root; 813 814 if ((m->flags & PG_UNMANAGED) == 0) 815 vm_page_lock_assert(m, MA_OWNED); 816 if ((object = m->object) == NULL) 817 return; 818 VM_OBJECT_LOCK_ASSERT(object, MA_OWNED); 819 if (m->oflags & VPO_BUSY) { 820 m->oflags &= ~VPO_BUSY; 821 vm_page_flash(m); 822 } 823 824 /* 825 * Now remove from the object's list of backed pages. 826 */ 827 if (m != object->root) 828 vm_page_splay(m->pindex, object->root); 829 if (m->left == NULL) 830 root = m->right; 831 else { 832 root = vm_page_splay(m->pindex, m->left); 833 root->right = m->right; 834 } 835 object->root = root; 836 TAILQ_REMOVE(&object->memq, m, listq); 837 838 /* 839 * And show that the object has one fewer resident page. 840 */ 841 object->resident_page_count--; 842 object->generation++; 843 /* 844 * The vnode may now be recycled. 845 */ 846 if (object->resident_page_count == 0 && object->type == OBJT_VNODE) 847 vdrop((struct vnode *)object->handle); 848 849 m->object = NULL; 850 } 851 852 /* 853 * vm_page_lookup: 854 * 855 * Returns the page associated with the object/offset 856 * pair specified; if none is found, NULL is returned. 857 * 858 * The object must be locked. 859 * This routine may not block. 860 * This is a critical path routine 861 */ 862 vm_page_t 863 vm_page_lookup(vm_object_t object, vm_pindex_t pindex) 864 { 865 vm_page_t m; 866 867 VM_OBJECT_LOCK_ASSERT(object, MA_OWNED); 868 if ((m = object->root) != NULL && m->pindex != pindex) { 869 m = vm_page_splay(pindex, m); 870 if ((object->root = m)->pindex != pindex) 871 m = NULL; 872 } 873 return (m); 874 } 875 876 /* 877 * vm_page_rename: 878 * 879 * Move the given memory entry from its 880 * current object to the specified target object/offset. 881 * 882 * The object must be locked. 883 * This routine may not block. 884 * 885 * Note: swap associated with the page must be invalidated by the move. We 886 * have to do this for several reasons: (1) we aren't freeing the 887 * page, (2) we are dirtying the page, (3) the VM system is probably 888 * moving the page from object A to B, and will then later move 889 * the backing store from A to B and we can't have a conflict. 890 * 891 * Note: we *always* dirty the page. It is necessary both for the 892 * fact that we moved it, and because we may be invalidating 893 * swap. If the page is on the cache, we have to deactivate it 894 * or vm_page_dirty() will panic. Dirty pages are not allowed 895 * on the cache. 896 */ 897 void 898 vm_page_rename(vm_page_t m, vm_object_t new_object, vm_pindex_t new_pindex) 899 { 900 901 vm_page_remove(m); 902 vm_page_insert(m, new_object, new_pindex); 903 vm_page_dirty(m); 904 } 905 906 /* 907 * Convert all of the given object's cached pages that have a 908 * pindex within the given range into free pages. If the value 909 * zero is given for "end", then the range's upper bound is 910 * infinity. If the given object is backed by a vnode and it 911 * transitions from having one or more cached pages to none, the 912 * vnode's hold count is reduced. 913 */ 914 void 915 vm_page_cache_free(vm_object_t object, vm_pindex_t start, vm_pindex_t end) 916 { 917 vm_page_t m, m_next; 918 boolean_t empty; 919 920 mtx_lock(&vm_page_queue_free_mtx); 921 if (__predict_false(object->cache == NULL)) { 922 mtx_unlock(&vm_page_queue_free_mtx); 923 return; 924 } 925 m = object->cache = vm_page_splay(start, object->cache); 926 if (m->pindex < start) { 927 if (m->right == NULL) 928 m = NULL; 929 else { 930 m_next = vm_page_splay(start, m->right); 931 m_next->left = m; 932 m->right = NULL; 933 m = object->cache = m_next; 934 } 935 } 936 937 /* 938 * At this point, "m" is either (1) a reference to the page 939 * with the least pindex that is greater than or equal to 940 * "start" or (2) NULL. 941 */ 942 for (; m != NULL && (m->pindex < end || end == 0); m = m_next) { 943 /* 944 * Find "m"'s successor and remove "m" from the 945 * object's cache. 946 */ 947 if (m->right == NULL) { 948 object->cache = m->left; 949 m_next = NULL; 950 } else { 951 m_next = vm_page_splay(start, m->right); 952 m_next->left = m->left; 953 object->cache = m_next; 954 } 955 /* Convert "m" to a free page. */ 956 m->object = NULL; 957 m->valid = 0; 958 /* Clear PG_CACHED and set PG_FREE. */ 959 m->flags ^= PG_CACHED | PG_FREE; 960 KASSERT((m->flags & (PG_CACHED | PG_FREE)) == PG_FREE, 961 ("vm_page_cache_free: page %p has inconsistent flags", m)); 962 cnt.v_cache_count--; 963 cnt.v_free_count++; 964 } 965 empty = object->cache == NULL; 966 mtx_unlock(&vm_page_queue_free_mtx); 967 if (object->type == OBJT_VNODE && empty) 968 vdrop(object->handle); 969 } 970 971 /* 972 * Returns the cached page that is associated with the given 973 * object and offset. If, however, none exists, returns NULL. 974 * 975 * The free page queue must be locked. 976 */ 977 static inline vm_page_t 978 vm_page_cache_lookup(vm_object_t object, vm_pindex_t pindex) 979 { 980 vm_page_t m; 981 982 mtx_assert(&vm_page_queue_free_mtx, MA_OWNED); 983 if ((m = object->cache) != NULL && m->pindex != pindex) { 984 m = vm_page_splay(pindex, m); 985 if ((object->cache = m)->pindex != pindex) 986 m = NULL; 987 } 988 return (m); 989 } 990 991 /* 992 * Remove the given cached page from its containing object's 993 * collection of cached pages. 994 * 995 * The free page queue must be locked. 996 */ 997 void 998 vm_page_cache_remove(vm_page_t m) 999 { 1000 vm_object_t object; 1001 vm_page_t root; 1002 1003 mtx_assert(&vm_page_queue_free_mtx, MA_OWNED); 1004 KASSERT((m->flags & PG_CACHED) != 0, 1005 ("vm_page_cache_remove: page %p is not cached", m)); 1006 object = m->object; 1007 if (m != object->cache) { 1008 root = vm_page_splay(m->pindex, object->cache); 1009 KASSERT(root == m, 1010 ("vm_page_cache_remove: page %p is not cached in object %p", 1011 m, object)); 1012 } 1013 if (m->left == NULL) 1014 root = m->right; 1015 else if (m->right == NULL) 1016 root = m->left; 1017 else { 1018 root = vm_page_splay(m->pindex, m->left); 1019 root->right = m->right; 1020 } 1021 object->cache = root; 1022 m->object = NULL; 1023 cnt.v_cache_count--; 1024 } 1025 1026 /* 1027 * Transfer all of the cached pages with offset greater than or 1028 * equal to 'offidxstart' from the original object's cache to the 1029 * new object's cache. However, any cached pages with offset 1030 * greater than or equal to the new object's size are kept in the 1031 * original object. Initially, the new object's cache must be 1032 * empty. Offset 'offidxstart' in the original object must 1033 * correspond to offset zero in the new object. 1034 * 1035 * The new object must be locked. 1036 */ 1037 void 1038 vm_page_cache_transfer(vm_object_t orig_object, vm_pindex_t offidxstart, 1039 vm_object_t new_object) 1040 { 1041 vm_page_t m, m_next; 1042 1043 /* 1044 * Insertion into an object's collection of cached pages 1045 * requires the object to be locked. In contrast, removal does 1046 * not. 1047 */ 1048 VM_OBJECT_LOCK_ASSERT(new_object, MA_OWNED); 1049 KASSERT(new_object->cache == NULL, 1050 ("vm_page_cache_transfer: object %p has cached pages", 1051 new_object)); 1052 mtx_lock(&vm_page_queue_free_mtx); 1053 if ((m = orig_object->cache) != NULL) { 1054 /* 1055 * Transfer all of the pages with offset greater than or 1056 * equal to 'offidxstart' from the original object's 1057 * cache to the new object's cache. 1058 */ 1059 m = vm_page_splay(offidxstart, m); 1060 if (m->pindex < offidxstart) { 1061 orig_object->cache = m; 1062 new_object->cache = m->right; 1063 m->right = NULL; 1064 } else { 1065 orig_object->cache = m->left; 1066 new_object->cache = m; 1067 m->left = NULL; 1068 } 1069 while ((m = new_object->cache) != NULL) { 1070 if ((m->pindex - offidxstart) >= new_object->size) { 1071 /* 1072 * Return all of the cached pages with 1073 * offset greater than or equal to the 1074 * new object's size to the original 1075 * object's cache. 1076 */ 1077 new_object->cache = m->left; 1078 m->left = orig_object->cache; 1079 orig_object->cache = m; 1080 break; 1081 } 1082 m_next = vm_page_splay(m->pindex, m->right); 1083 /* Update the page's object and offset. */ 1084 m->object = new_object; 1085 m->pindex -= offidxstart; 1086 if (m_next == NULL) 1087 break; 1088 m->right = NULL; 1089 m_next->left = m; 1090 new_object->cache = m_next; 1091 } 1092 KASSERT(new_object->cache == NULL || 1093 new_object->type == OBJT_SWAP, 1094 ("vm_page_cache_transfer: object %p's type is incompatible" 1095 " with cached pages", new_object)); 1096 } 1097 mtx_unlock(&vm_page_queue_free_mtx); 1098 } 1099 1100 /* 1101 * vm_page_alloc: 1102 * 1103 * Allocate and return a memory cell associated 1104 * with this VM object/offset pair. 1105 * 1106 * page_req classes: 1107 * VM_ALLOC_NORMAL normal process request 1108 * VM_ALLOC_SYSTEM system *really* needs a page 1109 * VM_ALLOC_INTERRUPT interrupt time request 1110 * VM_ALLOC_ZERO zero page 1111 * VM_ALLOC_WIRED wire the allocated page 1112 * VM_ALLOC_NOOBJ page is not associated with a vm object 1113 * VM_ALLOC_NOBUSY do not set the page busy 1114 * VM_ALLOC_IFNOTCACHED return NULL, do not reactivate if the page 1115 * is cached 1116 * 1117 * This routine may not sleep. 1118 */ 1119 vm_page_t 1120 vm_page_alloc(vm_object_t object, vm_pindex_t pindex, int req) 1121 { 1122 struct vnode *vp = NULL; 1123 vm_object_t m_object; 1124 vm_page_t m; 1125 int flags, page_req; 1126 1127 page_req = req & VM_ALLOC_CLASS_MASK; 1128 KASSERT(curthread->td_intr_nesting_level == 0 || 1129 page_req == VM_ALLOC_INTERRUPT, 1130 ("vm_page_alloc(NORMAL|SYSTEM) in interrupt context")); 1131 1132 if ((req & VM_ALLOC_NOOBJ) == 0) { 1133 KASSERT(object != NULL, 1134 ("vm_page_alloc: NULL object.")); 1135 VM_OBJECT_LOCK_ASSERT(object, MA_OWNED); 1136 } 1137 1138 /* 1139 * The pager is allowed to eat deeper into the free page list. 1140 */ 1141 if ((curproc == pageproc) && (page_req != VM_ALLOC_INTERRUPT)) { 1142 page_req = VM_ALLOC_SYSTEM; 1143 }; 1144 1145 mtx_lock(&vm_page_queue_free_mtx); 1146 if (cnt.v_free_count + cnt.v_cache_count > cnt.v_free_reserved || 1147 (page_req == VM_ALLOC_SYSTEM && 1148 cnt.v_free_count + cnt.v_cache_count > cnt.v_interrupt_free_min) || 1149 (page_req == VM_ALLOC_INTERRUPT && 1150 cnt.v_free_count + cnt.v_cache_count > 0)) { 1151 /* 1152 * Allocate from the free queue if the number of free pages 1153 * exceeds the minimum for the request class. 1154 */ 1155 if (object != NULL && 1156 (m = vm_page_cache_lookup(object, pindex)) != NULL) { 1157 if ((req & VM_ALLOC_IFNOTCACHED) != 0) { 1158 mtx_unlock(&vm_page_queue_free_mtx); 1159 return (NULL); 1160 } 1161 if (vm_phys_unfree_page(m)) 1162 vm_phys_set_pool(VM_FREEPOOL_DEFAULT, m, 0); 1163 #if VM_NRESERVLEVEL > 0 1164 else if (!vm_reserv_reactivate_page(m)) 1165 #else 1166 else 1167 #endif 1168 panic("vm_page_alloc: cache page %p is missing" 1169 " from the free queue", m); 1170 } else if ((req & VM_ALLOC_IFCACHED) != 0) { 1171 mtx_unlock(&vm_page_queue_free_mtx); 1172 return (NULL); 1173 #if VM_NRESERVLEVEL > 0 1174 } else if (object == NULL || object->type == OBJT_DEVICE || 1175 object->type == OBJT_SG || 1176 (object->flags & OBJ_COLORED) == 0 || 1177 (m = vm_reserv_alloc_page(object, pindex)) == NULL) { 1178 #else 1179 } else { 1180 #endif 1181 m = vm_phys_alloc_pages(object != NULL ? 1182 VM_FREEPOOL_DEFAULT : VM_FREEPOOL_DIRECT, 0); 1183 #if VM_NRESERVLEVEL > 0 1184 if (m == NULL && vm_reserv_reclaim_inactive()) { 1185 m = vm_phys_alloc_pages(object != NULL ? 1186 VM_FREEPOOL_DEFAULT : VM_FREEPOOL_DIRECT, 1187 0); 1188 } 1189 #endif 1190 } 1191 } else { 1192 /* 1193 * Not allocatable, give up. 1194 */ 1195 mtx_unlock(&vm_page_queue_free_mtx); 1196 atomic_add_int(&vm_pageout_deficit, 1); 1197 pagedaemon_wakeup(); 1198 return (NULL); 1199 } 1200 1201 /* 1202 * At this point we had better have found a good page. 1203 */ 1204 1205 KASSERT(m != NULL, ("vm_page_alloc: missing page")); 1206 KASSERT(m->queue == PQ_NONE, 1207 ("vm_page_alloc: page %p has unexpected queue %d", m, m->queue)); 1208 KASSERT(m->wire_count == 0, ("vm_page_alloc: page %p is wired", m)); 1209 KASSERT(m->hold_count == 0, ("vm_page_alloc: page %p is held", m)); 1210 KASSERT(m->busy == 0, ("vm_page_alloc: page %p is busy", m)); 1211 KASSERT(m->dirty == 0, ("vm_page_alloc: page %p is dirty", m)); 1212 KASSERT(pmap_page_get_memattr(m) == VM_MEMATTR_DEFAULT, 1213 ("vm_page_alloc: page %p has unexpected memattr %d", m, 1214 pmap_page_get_memattr(m))); 1215 if ((m->flags & PG_CACHED) != 0) { 1216 KASSERT(m->valid != 0, 1217 ("vm_page_alloc: cached page %p is invalid", m)); 1218 if (m->object == object && m->pindex == pindex) 1219 cnt.v_reactivated++; 1220 else 1221 m->valid = 0; 1222 m_object = m->object; 1223 vm_page_cache_remove(m); 1224 if (m_object->type == OBJT_VNODE && m_object->cache == NULL) 1225 vp = m_object->handle; 1226 } else { 1227 KASSERT(VM_PAGE_IS_FREE(m), 1228 ("vm_page_alloc: page %p is not free", m)); 1229 KASSERT(m->valid == 0, 1230 ("vm_page_alloc: free page %p is valid", m)); 1231 cnt.v_free_count--; 1232 } 1233 1234 /* 1235 * Initialize structure. Only the PG_ZERO flag is inherited. 1236 */ 1237 flags = 0; 1238 if (m->flags & PG_ZERO) { 1239 vm_page_zero_count--; 1240 if (req & VM_ALLOC_ZERO) 1241 flags = PG_ZERO; 1242 } 1243 if (object == NULL || object->type == OBJT_PHYS) 1244 flags |= PG_UNMANAGED; 1245 m->flags = flags; 1246 if (req & (VM_ALLOC_NOBUSY | VM_ALLOC_NOOBJ)) 1247 m->oflags = 0; 1248 else 1249 m->oflags = VPO_BUSY; 1250 if (req & VM_ALLOC_WIRED) { 1251 atomic_add_int(&cnt.v_wire_count, 1); 1252 m->wire_count = 1; 1253 } 1254 m->act_count = 0; 1255 mtx_unlock(&vm_page_queue_free_mtx); 1256 1257 if (object != NULL) { 1258 /* Ignore device objects; the pager sets "memattr" for them. */ 1259 if (object->memattr != VM_MEMATTR_DEFAULT && 1260 object->type != OBJT_DEVICE && object->type != OBJT_SG) 1261 pmap_page_set_memattr(m, object->memattr); 1262 vm_page_insert(m, object, pindex); 1263 } else 1264 m->pindex = pindex; 1265 1266 /* 1267 * The following call to vdrop() must come after the above call 1268 * to vm_page_insert() in case both affect the same object and 1269 * vnode. Otherwise, the affected vnode's hold count could 1270 * temporarily become zero. 1271 */ 1272 if (vp != NULL) 1273 vdrop(vp); 1274 1275 /* 1276 * Don't wakeup too often - wakeup the pageout daemon when 1277 * we would be nearly out of memory. 1278 */ 1279 if (vm_paging_needed()) 1280 pagedaemon_wakeup(); 1281 1282 return (m); 1283 } 1284 1285 /* 1286 * vm_wait: (also see VM_WAIT macro) 1287 * 1288 * Block until free pages are available for allocation 1289 * - Called in various places before memory allocations. 1290 */ 1291 void 1292 vm_wait(void) 1293 { 1294 1295 mtx_lock(&vm_page_queue_free_mtx); 1296 if (curproc == pageproc) { 1297 vm_pageout_pages_needed = 1; 1298 msleep(&vm_pageout_pages_needed, &vm_page_queue_free_mtx, 1299 PDROP | PSWP, "VMWait", 0); 1300 } else { 1301 if (!vm_pages_needed) { 1302 vm_pages_needed = 1; 1303 wakeup(&vm_pages_needed); 1304 } 1305 msleep(&cnt.v_free_count, &vm_page_queue_free_mtx, PDROP | PVM, 1306 "vmwait", 0); 1307 } 1308 } 1309 1310 /* 1311 * vm_waitpfault: (also see VM_WAITPFAULT macro) 1312 * 1313 * Block until free pages are available for allocation 1314 * - Called only in vm_fault so that processes page faulting 1315 * can be easily tracked. 1316 * - Sleeps at a lower priority than vm_wait() so that vm_wait()ing 1317 * processes will be able to grab memory first. Do not change 1318 * this balance without careful testing first. 1319 */ 1320 void 1321 vm_waitpfault(void) 1322 { 1323 1324 mtx_lock(&vm_page_queue_free_mtx); 1325 if (!vm_pages_needed) { 1326 vm_pages_needed = 1; 1327 wakeup(&vm_pages_needed); 1328 } 1329 msleep(&cnt.v_free_count, &vm_page_queue_free_mtx, PDROP | PUSER, 1330 "pfault", 0); 1331 } 1332 1333 /* 1334 * vm_page_requeue: 1335 * 1336 * If the given page is contained within a page queue, move it to the tail 1337 * of that queue. 1338 * 1339 * The page queues must be locked. 1340 */ 1341 void 1342 vm_page_requeue(vm_page_t m) 1343 { 1344 int queue = VM_PAGE_GETQUEUE(m); 1345 struct vpgqueues *vpq; 1346 1347 if (queue != PQ_NONE) { 1348 vpq = &vm_page_queues[queue]; 1349 TAILQ_REMOVE(&vpq->pl, m, pageq); 1350 TAILQ_INSERT_TAIL(&vpq->pl, m, pageq); 1351 } 1352 } 1353 1354 /* 1355 * vm_page_queue_remove: 1356 * 1357 * Remove the given page from the specified queue. 1358 * 1359 * The page and page queues must be locked. 1360 */ 1361 static __inline void 1362 vm_page_queue_remove(int queue, vm_page_t m) 1363 { 1364 struct vpgqueues *pq; 1365 1366 mtx_assert(&vm_page_queue_mtx, MA_OWNED); 1367 vm_page_lock_assert(m, MA_OWNED); 1368 pq = &vm_page_queues[queue]; 1369 TAILQ_REMOVE(&pq->pl, m, pageq); 1370 (*pq->cnt)--; 1371 } 1372 1373 /* 1374 * vm_pageq_remove: 1375 * 1376 * Remove a page from its queue. 1377 * 1378 * The given page must be locked. 1379 * This routine may not block. 1380 */ 1381 void 1382 vm_pageq_remove(vm_page_t m) 1383 { 1384 int queue = VM_PAGE_GETQUEUE(m); 1385 1386 vm_page_lock_assert(m, MA_OWNED); 1387 if (queue != PQ_NONE) { 1388 vm_page_lock_queues(); 1389 VM_PAGE_SETQUEUE2(m, PQ_NONE); 1390 vm_page_queue_remove(queue, m); 1391 vm_page_unlock_queues(); 1392 } 1393 } 1394 1395 /* 1396 * vm_page_enqueue: 1397 * 1398 * Add the given page to the specified queue. 1399 * 1400 * The page queues must be locked. 1401 */ 1402 static void 1403 vm_page_enqueue(int queue, vm_page_t m) 1404 { 1405 struct vpgqueues *vpq; 1406 1407 vpq = &vm_page_queues[queue]; 1408 VM_PAGE_SETQUEUE2(m, queue); 1409 TAILQ_INSERT_TAIL(&vpq->pl, m, pageq); 1410 ++*vpq->cnt; 1411 } 1412 1413 /* 1414 * vm_page_activate: 1415 * 1416 * Put the specified page on the active list (if appropriate). 1417 * Ensure that act_count is at least ACT_INIT but do not otherwise 1418 * mess with it. 1419 * 1420 * The page must be locked. 1421 * This routine may not block. 1422 */ 1423 void 1424 vm_page_activate(vm_page_t m) 1425 { 1426 int queue; 1427 1428 vm_page_lock_assert(m, MA_OWNED); 1429 if ((queue = VM_PAGE_GETKNOWNQUEUE2(m)) != PQ_ACTIVE) { 1430 if (m->wire_count == 0 && (m->flags & PG_UNMANAGED) == 0) { 1431 if (m->act_count < ACT_INIT) 1432 m->act_count = ACT_INIT; 1433 vm_page_lock_queues(); 1434 if (queue != PQ_NONE) 1435 vm_page_queue_remove(queue, m); 1436 vm_page_enqueue(PQ_ACTIVE, m); 1437 vm_page_unlock_queues(); 1438 } else 1439 KASSERT(queue == PQ_NONE, 1440 ("vm_page_activate: wired page %p is queued", m)); 1441 } else { 1442 if (m->act_count < ACT_INIT) 1443 m->act_count = ACT_INIT; 1444 } 1445 } 1446 1447 /* 1448 * vm_page_free_wakeup: 1449 * 1450 * Helper routine for vm_page_free_toq() and vm_page_cache(). This 1451 * routine is called when a page has been added to the cache or free 1452 * queues. 1453 * 1454 * The page queues must be locked. 1455 * This routine may not block. 1456 */ 1457 static inline void 1458 vm_page_free_wakeup(void) 1459 { 1460 1461 mtx_assert(&vm_page_queue_free_mtx, MA_OWNED); 1462 /* 1463 * if pageout daemon needs pages, then tell it that there are 1464 * some free. 1465 */ 1466 if (vm_pageout_pages_needed && 1467 cnt.v_cache_count + cnt.v_free_count >= cnt.v_pageout_free_min) { 1468 wakeup(&vm_pageout_pages_needed); 1469 vm_pageout_pages_needed = 0; 1470 } 1471 /* 1472 * wakeup processes that are waiting on memory if we hit a 1473 * high water mark. And wakeup scheduler process if we have 1474 * lots of memory. this process will swapin processes. 1475 */ 1476 if (vm_pages_needed && !vm_page_count_min()) { 1477 vm_pages_needed = 0; 1478 wakeup(&cnt.v_free_count); 1479 } 1480 } 1481 1482 /* 1483 * vm_page_free_toq: 1484 * 1485 * Returns the given page to the free list, 1486 * disassociating it with any VM object. 1487 * 1488 * Object and page must be locked prior to entry. 1489 * This routine may not block. 1490 */ 1491 1492 void 1493 vm_page_free_toq(vm_page_t m) 1494 { 1495 1496 if ((m->flags & PG_UNMANAGED) == 0) { 1497 vm_page_lock_assert(m, MA_OWNED); 1498 KASSERT(!pmap_page_is_mapped(m), 1499 ("vm_page_free_toq: freeing mapped page %p", m)); 1500 } 1501 PCPU_INC(cnt.v_tfree); 1502 1503 if (m->busy || VM_PAGE_IS_FREE(m)) { 1504 printf( 1505 "vm_page_free: pindex(%lu), busy(%d), VPO_BUSY(%d), hold(%d)\n", 1506 (u_long)m->pindex, m->busy, (m->oflags & VPO_BUSY) ? 1 : 0, 1507 m->hold_count); 1508 if (VM_PAGE_IS_FREE(m)) 1509 panic("vm_page_free: freeing free page"); 1510 else 1511 panic("vm_page_free: freeing busy page"); 1512 } 1513 1514 /* 1515 * unqueue, then remove page. Note that we cannot destroy 1516 * the page here because we do not want to call the pager's 1517 * callback routine until after we've put the page on the 1518 * appropriate free queue. 1519 */ 1520 if ((m->flags & PG_UNMANAGED) == 0) 1521 vm_pageq_remove(m); 1522 vm_page_remove(m); 1523 1524 /* 1525 * If fictitious remove object association and 1526 * return, otherwise delay object association removal. 1527 */ 1528 if ((m->flags & PG_FICTITIOUS) != 0) { 1529 return; 1530 } 1531 1532 m->valid = 0; 1533 vm_page_undirty(m); 1534 1535 if (m->wire_count != 0) { 1536 if (m->wire_count > 1) { 1537 panic("vm_page_free: invalid wire count (%d), pindex: 0x%lx", 1538 m->wire_count, (long)m->pindex); 1539 } 1540 panic("vm_page_free: freeing wired page"); 1541 } 1542 if (m->hold_count != 0) { 1543 m->flags &= ~PG_ZERO; 1544 vm_page_lock_queues(); 1545 vm_page_enqueue(PQ_HOLD, m); 1546 vm_page_unlock_queues(); 1547 } else { 1548 /* 1549 * Restore the default memory attribute to the page. 1550 */ 1551 if (pmap_page_get_memattr(m) != VM_MEMATTR_DEFAULT) 1552 pmap_page_set_memattr(m, VM_MEMATTR_DEFAULT); 1553 1554 /* 1555 * Insert the page into the physical memory allocator's 1556 * cache/free page queues. 1557 */ 1558 mtx_lock(&vm_page_queue_free_mtx); 1559 m->flags |= PG_FREE; 1560 cnt.v_free_count++; 1561 #if VM_NRESERVLEVEL > 0 1562 if (!vm_reserv_free_page(m)) 1563 #else 1564 if (TRUE) 1565 #endif 1566 vm_phys_free_pages(m, 0); 1567 if ((m->flags & PG_ZERO) != 0) 1568 ++vm_page_zero_count; 1569 else 1570 vm_page_zero_idle_wakeup(); 1571 vm_page_free_wakeup(); 1572 mtx_unlock(&vm_page_queue_free_mtx); 1573 } 1574 } 1575 1576 /* 1577 * vm_page_wire: 1578 * 1579 * Mark this page as wired down by yet 1580 * another map, removing it from paging queues 1581 * as necessary. 1582 * 1583 * The page must be locked. 1584 * This routine may not block. 1585 */ 1586 void 1587 vm_page_wire(vm_page_t m) 1588 { 1589 1590 /* 1591 * Only bump the wire statistics if the page is not already wired, 1592 * and only unqueue the page if it is on some queue (if it is unmanaged 1593 * it is already off the queues). 1594 */ 1595 vm_page_lock_assert(m, MA_OWNED); 1596 if (m->flags & PG_FICTITIOUS) 1597 return; 1598 if (m->wire_count == 0) { 1599 if ((m->flags & PG_UNMANAGED) == 0) 1600 vm_pageq_remove(m); 1601 atomic_add_int(&cnt.v_wire_count, 1); 1602 } 1603 m->wire_count++; 1604 KASSERT(m->wire_count != 0, ("vm_page_wire: wire_count overflow m=%p", m)); 1605 } 1606 1607 /* 1608 * vm_page_unwire: 1609 * 1610 * Release one wiring of this page, potentially 1611 * enabling it to be paged again. 1612 * 1613 * Many pages placed on the inactive queue should actually go 1614 * into the cache, but it is difficult to figure out which. What 1615 * we do instead, if the inactive target is well met, is to put 1616 * clean pages at the head of the inactive queue instead of the tail. 1617 * This will cause them to be moved to the cache more quickly and 1618 * if not actively re-referenced, freed more quickly. If we just 1619 * stick these pages at the end of the inactive queue, heavy filesystem 1620 * meta-data accesses can cause an unnecessary paging load on memory bound 1621 * processes. This optimization causes one-time-use metadata to be 1622 * reused more quickly. 1623 * 1624 * BUT, if we are in a low-memory situation we have no choice but to 1625 * put clean pages on the cache queue. 1626 * 1627 * A number of routines use vm_page_unwire() to guarantee that the page 1628 * will go into either the inactive or active queues, and will NEVER 1629 * be placed in the cache - for example, just after dirtying a page. 1630 * dirty pages in the cache are not allowed. 1631 * 1632 * The page must be locked. 1633 * This routine may not block. 1634 */ 1635 void 1636 vm_page_unwire(vm_page_t m, int activate) 1637 { 1638 1639 if ((m->flags & PG_UNMANAGED) == 0) 1640 vm_page_lock_assert(m, MA_OWNED); 1641 if (m->flags & PG_FICTITIOUS) 1642 return; 1643 if (m->wire_count > 0) { 1644 m->wire_count--; 1645 if (m->wire_count == 0) { 1646 atomic_subtract_int(&cnt.v_wire_count, 1); 1647 if ((m->flags & PG_UNMANAGED) != 0) 1648 return; 1649 vm_page_lock_queues(); 1650 if (activate) 1651 vm_page_enqueue(PQ_ACTIVE, m); 1652 else { 1653 vm_page_flag_clear(m, PG_WINATCFLS); 1654 vm_page_enqueue(PQ_INACTIVE, m); 1655 } 1656 vm_page_unlock_queues(); 1657 } 1658 } else { 1659 panic("vm_page_unwire: invalid wire count: %d", m->wire_count); 1660 } 1661 } 1662 1663 /* 1664 * Move the specified page to the inactive queue. 1665 * 1666 * Normally athead is 0 resulting in LRU operation. athead is set 1667 * to 1 if we want this page to be 'as if it were placed in the cache', 1668 * except without unmapping it from the process address space. 1669 * 1670 * This routine may not block. 1671 */ 1672 static inline void 1673 _vm_page_deactivate(vm_page_t m, int athead) 1674 { 1675 int queue; 1676 1677 vm_page_lock_assert(m, MA_OWNED); 1678 1679 /* 1680 * Ignore if already inactive. 1681 */ 1682 if ((queue = VM_PAGE_GETKNOWNQUEUE2(m)) == PQ_INACTIVE) 1683 return; 1684 if (m->wire_count == 0 && (m->flags & PG_UNMANAGED) == 0) { 1685 vm_page_lock_queues(); 1686 vm_page_flag_clear(m, PG_WINATCFLS); 1687 if (queue != PQ_NONE) 1688 vm_page_queue_remove(queue, m); 1689 if (athead) 1690 TAILQ_INSERT_HEAD(&vm_page_queues[PQ_INACTIVE].pl, m, 1691 pageq); 1692 else 1693 TAILQ_INSERT_TAIL(&vm_page_queues[PQ_INACTIVE].pl, m, 1694 pageq); 1695 VM_PAGE_SETQUEUE2(m, PQ_INACTIVE); 1696 cnt.v_inactive_count++; 1697 vm_page_unlock_queues(); 1698 } 1699 } 1700 1701 /* 1702 * Move the specified page to the inactive queue. 1703 * 1704 * The page must be locked. 1705 */ 1706 void 1707 vm_page_deactivate(vm_page_t m) 1708 { 1709 1710 _vm_page_deactivate(m, 0); 1711 } 1712 1713 /* 1714 * vm_page_try_to_cache: 1715 * 1716 * Returns 0 on failure, 1 on success 1717 */ 1718 int 1719 vm_page_try_to_cache(vm_page_t m) 1720 { 1721 1722 vm_page_lock_assert(m, MA_OWNED); 1723 VM_OBJECT_LOCK_ASSERT(m->object, MA_OWNED); 1724 if (m->dirty || m->hold_count || m->busy || m->wire_count || 1725 (m->oflags & VPO_BUSY) || (m->flags & PG_UNMANAGED)) 1726 return (0); 1727 pmap_remove_all(m); 1728 if (m->dirty) 1729 return (0); 1730 vm_page_cache(m); 1731 return (1); 1732 } 1733 1734 /* 1735 * vm_page_try_to_free() 1736 * 1737 * Attempt to free the page. If we cannot free it, we do nothing. 1738 * 1 is returned on success, 0 on failure. 1739 */ 1740 int 1741 vm_page_try_to_free(vm_page_t m) 1742 { 1743 1744 vm_page_lock_assert(m, MA_OWNED); 1745 if (m->object != NULL) 1746 VM_OBJECT_LOCK_ASSERT(m->object, MA_OWNED); 1747 if (m->dirty || m->hold_count || m->busy || m->wire_count || 1748 (m->oflags & VPO_BUSY) || (m->flags & PG_UNMANAGED)) 1749 return (0); 1750 pmap_remove_all(m); 1751 if (m->dirty) 1752 return (0); 1753 vm_page_free(m); 1754 return (1); 1755 } 1756 1757 /* 1758 * vm_page_cache 1759 * 1760 * Put the specified page onto the page cache queue (if appropriate). 1761 * 1762 * This routine may not block. 1763 */ 1764 void 1765 vm_page_cache(vm_page_t m) 1766 { 1767 vm_object_t object; 1768 vm_page_t root; 1769 1770 vm_page_lock_assert(m, MA_OWNED); 1771 object = m->object; 1772 VM_OBJECT_LOCK_ASSERT(object, MA_OWNED); 1773 if ((m->flags & PG_UNMANAGED) || (m->oflags & VPO_BUSY) || m->busy || 1774 m->hold_count || m->wire_count) 1775 panic("vm_page_cache: attempting to cache busy page"); 1776 pmap_remove_all(m); 1777 if (m->dirty != 0) 1778 panic("vm_page_cache: page %p is dirty", m); 1779 if (m->valid == 0 || object->type == OBJT_DEFAULT || 1780 (object->type == OBJT_SWAP && 1781 !vm_pager_has_page(object, m->pindex, NULL, NULL))) { 1782 /* 1783 * Hypothesis: A cache-elgible page belonging to a 1784 * default object or swap object but without a backing 1785 * store must be zero filled. 1786 */ 1787 vm_page_free(m); 1788 return; 1789 } 1790 KASSERT((m->flags & PG_CACHED) == 0, 1791 ("vm_page_cache: page %p is already cached", m)); 1792 PCPU_INC(cnt.v_tcached); 1793 1794 /* 1795 * Remove the page from the paging queues. 1796 */ 1797 vm_pageq_remove(m); 1798 1799 /* 1800 * Remove the page from the object's collection of resident 1801 * pages. 1802 */ 1803 if (m != object->root) 1804 vm_page_splay(m->pindex, object->root); 1805 if (m->left == NULL) 1806 root = m->right; 1807 else { 1808 root = vm_page_splay(m->pindex, m->left); 1809 root->right = m->right; 1810 } 1811 object->root = root; 1812 TAILQ_REMOVE(&object->memq, m, listq); 1813 object->resident_page_count--; 1814 object->generation++; 1815 1816 /* 1817 * Restore the default memory attribute to the page. 1818 */ 1819 if (pmap_page_get_memattr(m) != VM_MEMATTR_DEFAULT) 1820 pmap_page_set_memattr(m, VM_MEMATTR_DEFAULT); 1821 1822 /* 1823 * Insert the page into the object's collection of cached pages 1824 * and the physical memory allocator's cache/free page queues. 1825 */ 1826 m->flags &= ~PG_ZERO; 1827 mtx_lock(&vm_page_queue_free_mtx); 1828 m->flags |= PG_CACHED; 1829 cnt.v_cache_count++; 1830 root = object->cache; 1831 if (root == NULL) { 1832 m->left = NULL; 1833 m->right = NULL; 1834 } else { 1835 root = vm_page_splay(m->pindex, root); 1836 if (m->pindex < root->pindex) { 1837 m->left = root->left; 1838 m->right = root; 1839 root->left = NULL; 1840 } else if (__predict_false(m->pindex == root->pindex)) 1841 panic("vm_page_cache: offset already cached"); 1842 else { 1843 m->right = root->right; 1844 m->left = root; 1845 root->right = NULL; 1846 } 1847 } 1848 object->cache = m; 1849 #if VM_NRESERVLEVEL > 0 1850 if (!vm_reserv_free_page(m)) { 1851 #else 1852 if (TRUE) { 1853 #endif 1854 vm_phys_set_pool(VM_FREEPOOL_CACHE, m, 0); 1855 vm_phys_free_pages(m, 0); 1856 } 1857 vm_page_free_wakeup(); 1858 mtx_unlock(&vm_page_queue_free_mtx); 1859 1860 /* 1861 * Increment the vnode's hold count if this is the object's only 1862 * cached page. Decrement the vnode's hold count if this was 1863 * the object's only resident page. 1864 */ 1865 if (object->type == OBJT_VNODE) { 1866 if (root == NULL && object->resident_page_count != 0) 1867 vhold(object->handle); 1868 else if (root != NULL && object->resident_page_count == 0) 1869 vdrop(object->handle); 1870 } 1871 } 1872 1873 /* 1874 * vm_page_dontneed 1875 * 1876 * Cache, deactivate, or do nothing as appropriate. This routine 1877 * is typically used by madvise() MADV_DONTNEED. 1878 * 1879 * Generally speaking we want to move the page into the cache so 1880 * it gets reused quickly. However, this can result in a silly syndrome 1881 * due to the page recycling too quickly. Small objects will not be 1882 * fully cached. On the otherhand, if we move the page to the inactive 1883 * queue we wind up with a problem whereby very large objects 1884 * unnecessarily blow away our inactive and cache queues. 1885 * 1886 * The solution is to move the pages based on a fixed weighting. We 1887 * either leave them alone, deactivate them, or move them to the cache, 1888 * where moving them to the cache has the highest weighting. 1889 * By forcing some pages into other queues we eventually force the 1890 * system to balance the queues, potentially recovering other unrelated 1891 * space from active. The idea is to not force this to happen too 1892 * often. 1893 */ 1894 void 1895 vm_page_dontneed(vm_page_t m) 1896 { 1897 int dnw; 1898 int head; 1899 1900 vm_page_lock_assert(m, MA_OWNED); 1901 VM_OBJECT_LOCK_ASSERT(m->object, MA_OWNED); 1902 dnw = PCPU_GET(dnweight); 1903 PCPU_INC(dnweight); 1904 1905 /* 1906 * Occasionally leave the page alone. 1907 */ 1908 if ((dnw & 0x01F0) == 0 || 1909 VM_PAGE_INQUEUE2(m, PQ_INACTIVE)) { 1910 if (m->act_count >= ACT_INIT) 1911 --m->act_count; 1912 return; 1913 } 1914 1915 /* 1916 * Clear any references to the page. Otherwise, the page daemon will 1917 * immediately reactivate the page. 1918 * 1919 * Perform the pmap_clear_reference() first. Otherwise, a concurrent 1920 * pmap operation, such as pmap_remove(), could clear a reference in 1921 * the pmap and set PG_REFERENCED on the page before the 1922 * pmap_clear_reference() had completed. Consequently, the page would 1923 * appear referenced based upon an old reference that occurred before 1924 * this function ran. 1925 */ 1926 pmap_clear_reference(m); 1927 vm_page_lock_queues(); 1928 vm_page_flag_clear(m, PG_REFERENCED); 1929 vm_page_unlock_queues(); 1930 1931 if (m->dirty == 0 && pmap_is_modified(m)) 1932 vm_page_dirty(m); 1933 1934 if (m->dirty || (dnw & 0x0070) == 0) { 1935 /* 1936 * Deactivate the page 3 times out of 32. 1937 */ 1938 head = 0; 1939 } else { 1940 /* 1941 * Cache the page 28 times out of every 32. Note that 1942 * the page is deactivated instead of cached, but placed 1943 * at the head of the queue instead of the tail. 1944 */ 1945 head = 1; 1946 } 1947 _vm_page_deactivate(m, head); 1948 } 1949 1950 /* 1951 * Grab a page, waiting until we are waken up due to the page 1952 * changing state. We keep on waiting, if the page continues 1953 * to be in the object. If the page doesn't exist, first allocate it 1954 * and then conditionally zero it. 1955 * 1956 * This routine may block. 1957 */ 1958 vm_page_t 1959 vm_page_grab(vm_object_t object, vm_pindex_t pindex, int allocflags) 1960 { 1961 vm_page_t m; 1962 1963 VM_OBJECT_LOCK_ASSERT(object, MA_OWNED); 1964 retrylookup: 1965 if ((m = vm_page_lookup(object, pindex)) != NULL) { 1966 if ((m->oflags & VPO_BUSY) != 0 || m->busy != 0) { 1967 if ((allocflags & VM_ALLOC_RETRY) != 0) { 1968 /* 1969 * Reference the page before unlocking and 1970 * sleeping so that the page daemon is less 1971 * likely to reclaim it. 1972 */ 1973 vm_page_lock_queues(); 1974 vm_page_flag_set(m, PG_REFERENCED); 1975 } 1976 vm_page_sleep(m, "pgrbwt"); 1977 if ((allocflags & VM_ALLOC_RETRY) == 0) 1978 return (NULL); 1979 goto retrylookup; 1980 } else { 1981 if ((allocflags & VM_ALLOC_WIRED) != 0) { 1982 vm_page_lock(m); 1983 vm_page_wire(m); 1984 vm_page_unlock(m); 1985 } 1986 if ((allocflags & VM_ALLOC_NOBUSY) == 0) 1987 vm_page_busy(m); 1988 return (m); 1989 } 1990 } 1991 m = vm_page_alloc(object, pindex, allocflags & ~VM_ALLOC_RETRY); 1992 if (m == NULL) { 1993 VM_OBJECT_UNLOCK(object); 1994 VM_WAIT; 1995 VM_OBJECT_LOCK(object); 1996 if ((allocflags & VM_ALLOC_RETRY) == 0) 1997 return (NULL); 1998 goto retrylookup; 1999 } else if (m->valid != 0) 2000 return (m); 2001 if (allocflags & VM_ALLOC_ZERO && (m->flags & PG_ZERO) == 0) 2002 pmap_zero_page(m); 2003 return (m); 2004 } 2005 2006 /* 2007 * Mapping function for valid bits or for dirty bits in 2008 * a page. May not block. 2009 * 2010 * Inputs are required to range within a page. 2011 */ 2012 int 2013 vm_page_bits(int base, int size) 2014 { 2015 int first_bit; 2016 int last_bit; 2017 2018 KASSERT( 2019 base + size <= PAGE_SIZE, 2020 ("vm_page_bits: illegal base/size %d/%d", base, size) 2021 ); 2022 2023 if (size == 0) /* handle degenerate case */ 2024 return (0); 2025 2026 first_bit = base >> DEV_BSHIFT; 2027 last_bit = (base + size - 1) >> DEV_BSHIFT; 2028 2029 return ((2 << last_bit) - (1 << first_bit)); 2030 } 2031 2032 /* 2033 * vm_page_set_valid: 2034 * 2035 * Sets portions of a page valid. The arguments are expected 2036 * to be DEV_BSIZE aligned but if they aren't the bitmap is inclusive 2037 * of any partial chunks touched by the range. The invalid portion of 2038 * such chunks will be zeroed. 2039 * 2040 * (base + size) must be less then or equal to PAGE_SIZE. 2041 */ 2042 void 2043 vm_page_set_valid(vm_page_t m, int base, int size) 2044 { 2045 int endoff, frag; 2046 2047 VM_OBJECT_LOCK_ASSERT(m->object, MA_OWNED); 2048 if (size == 0) /* handle degenerate case */ 2049 return; 2050 2051 /* 2052 * If the base is not DEV_BSIZE aligned and the valid 2053 * bit is clear, we have to zero out a portion of the 2054 * first block. 2055 */ 2056 if ((frag = base & ~(DEV_BSIZE - 1)) != base && 2057 (m->valid & (1 << (base >> DEV_BSHIFT))) == 0) 2058 pmap_zero_page_area(m, frag, base - frag); 2059 2060 /* 2061 * If the ending offset is not DEV_BSIZE aligned and the 2062 * valid bit is clear, we have to zero out a portion of 2063 * the last block. 2064 */ 2065 endoff = base + size; 2066 if ((frag = endoff & ~(DEV_BSIZE - 1)) != endoff && 2067 (m->valid & (1 << (endoff >> DEV_BSHIFT))) == 0) 2068 pmap_zero_page_area(m, endoff, 2069 DEV_BSIZE - (endoff & (DEV_BSIZE - 1))); 2070 2071 /* 2072 * Assert that no previously invalid block that is now being validated 2073 * is already dirty. 2074 */ 2075 KASSERT((~m->valid & vm_page_bits(base, size) & m->dirty) == 0, 2076 ("vm_page_set_valid: page %p is dirty", m)); 2077 2078 /* 2079 * Set valid bits inclusive of any overlap. 2080 */ 2081 m->valid |= vm_page_bits(base, size); 2082 } 2083 2084 /* 2085 * Clear the given bits from the specified page's dirty field. 2086 */ 2087 static __inline void 2088 vm_page_clear_dirty_mask(vm_page_t m, int pagebits) 2089 { 2090 2091 /* 2092 * If the object is locked and the page is neither VPO_BUSY nor 2093 * PG_WRITEABLE, then the page's dirty field cannot possibly be 2094 * modified by a concurrent pmap operation. 2095 */ 2096 VM_OBJECT_LOCK_ASSERT(m->object, MA_OWNED); 2097 if ((m->oflags & VPO_BUSY) == 0 && (m->flags & PG_WRITEABLE) == 0) 2098 m->dirty &= ~pagebits; 2099 else { 2100 vm_page_lock_queues(); 2101 m->dirty &= ~pagebits; 2102 vm_page_unlock_queues(); 2103 } 2104 } 2105 2106 /* 2107 * vm_page_set_validclean: 2108 * 2109 * Sets portions of a page valid and clean. The arguments are expected 2110 * to be DEV_BSIZE aligned but if they aren't the bitmap is inclusive 2111 * of any partial chunks touched by the range. The invalid portion of 2112 * such chunks will be zero'd. 2113 * 2114 * This routine may not block. 2115 * 2116 * (base + size) must be less then or equal to PAGE_SIZE. 2117 */ 2118 void 2119 vm_page_set_validclean(vm_page_t m, int base, int size) 2120 { 2121 u_long oldvalid; 2122 int endoff, frag, pagebits; 2123 2124 VM_OBJECT_LOCK_ASSERT(m->object, MA_OWNED); 2125 if (size == 0) /* handle degenerate case */ 2126 return; 2127 2128 /* 2129 * If the base is not DEV_BSIZE aligned and the valid 2130 * bit is clear, we have to zero out a portion of the 2131 * first block. 2132 */ 2133 if ((frag = base & ~(DEV_BSIZE - 1)) != base && 2134 (m->valid & (1 << (base >> DEV_BSHIFT))) == 0) 2135 pmap_zero_page_area(m, frag, base - frag); 2136 2137 /* 2138 * If the ending offset is not DEV_BSIZE aligned and the 2139 * valid bit is clear, we have to zero out a portion of 2140 * the last block. 2141 */ 2142 endoff = base + size; 2143 if ((frag = endoff & ~(DEV_BSIZE - 1)) != endoff && 2144 (m->valid & (1 << (endoff >> DEV_BSHIFT))) == 0) 2145 pmap_zero_page_area(m, endoff, 2146 DEV_BSIZE - (endoff & (DEV_BSIZE - 1))); 2147 2148 /* 2149 * Set valid, clear dirty bits. If validating the entire 2150 * page we can safely clear the pmap modify bit. We also 2151 * use this opportunity to clear the VPO_NOSYNC flag. If a process 2152 * takes a write fault on a MAP_NOSYNC memory area the flag will 2153 * be set again. 2154 * 2155 * We set valid bits inclusive of any overlap, but we can only 2156 * clear dirty bits for DEV_BSIZE chunks that are fully within 2157 * the range. 2158 */ 2159 oldvalid = m->valid; 2160 pagebits = vm_page_bits(base, size); 2161 m->valid |= pagebits; 2162 #if 0 /* NOT YET */ 2163 if ((frag = base & (DEV_BSIZE - 1)) != 0) { 2164 frag = DEV_BSIZE - frag; 2165 base += frag; 2166 size -= frag; 2167 if (size < 0) 2168 size = 0; 2169 } 2170 pagebits = vm_page_bits(base, size & (DEV_BSIZE - 1)); 2171 #endif 2172 if (base == 0 && size == PAGE_SIZE) { 2173 /* 2174 * The page can only be modified within the pmap if it is 2175 * mapped, and it can only be mapped if it was previously 2176 * fully valid. 2177 */ 2178 if (oldvalid == VM_PAGE_BITS_ALL) 2179 /* 2180 * Perform the pmap_clear_modify() first. Otherwise, 2181 * a concurrent pmap operation, such as 2182 * pmap_protect(), could clear a modification in the 2183 * pmap and set the dirty field on the page before 2184 * pmap_clear_modify() had begun and after the dirty 2185 * field was cleared here. 2186 */ 2187 pmap_clear_modify(m); 2188 m->dirty = 0; 2189 m->oflags &= ~VPO_NOSYNC; 2190 } else if (oldvalid != VM_PAGE_BITS_ALL) 2191 m->dirty &= ~pagebits; 2192 else 2193 vm_page_clear_dirty_mask(m, pagebits); 2194 } 2195 2196 void 2197 vm_page_clear_dirty(vm_page_t m, int base, int size) 2198 { 2199 2200 vm_page_clear_dirty_mask(m, vm_page_bits(base, size)); 2201 } 2202 2203 /* 2204 * vm_page_set_invalid: 2205 * 2206 * Invalidates DEV_BSIZE'd chunks within a page. Both the 2207 * valid and dirty bits for the effected areas are cleared. 2208 * 2209 * May not block. 2210 */ 2211 void 2212 vm_page_set_invalid(vm_page_t m, int base, int size) 2213 { 2214 int bits; 2215 2216 VM_OBJECT_LOCK_ASSERT(m->object, MA_OWNED); 2217 KASSERT((m->oflags & VPO_BUSY) == 0, 2218 ("vm_page_set_invalid: page %p is busy", m)); 2219 bits = vm_page_bits(base, size); 2220 if (m->valid == VM_PAGE_BITS_ALL && bits != 0) 2221 pmap_remove_all(m); 2222 KASSERT(!pmap_page_is_mapped(m), 2223 ("vm_page_set_invalid: page %p is mapped", m)); 2224 m->valid &= ~bits; 2225 m->dirty &= ~bits; 2226 m->object->generation++; 2227 } 2228 2229 /* 2230 * vm_page_zero_invalid() 2231 * 2232 * The kernel assumes that the invalid portions of a page contain 2233 * garbage, but such pages can be mapped into memory by user code. 2234 * When this occurs, we must zero out the non-valid portions of the 2235 * page so user code sees what it expects. 2236 * 2237 * Pages are most often semi-valid when the end of a file is mapped 2238 * into memory and the file's size is not page aligned. 2239 */ 2240 void 2241 vm_page_zero_invalid(vm_page_t m, boolean_t setvalid) 2242 { 2243 int b; 2244 int i; 2245 2246 VM_OBJECT_LOCK_ASSERT(m->object, MA_OWNED); 2247 /* 2248 * Scan the valid bits looking for invalid sections that 2249 * must be zerod. Invalid sub-DEV_BSIZE'd areas ( where the 2250 * valid bit may be set ) have already been zerod by 2251 * vm_page_set_validclean(). 2252 */ 2253 for (b = i = 0; i <= PAGE_SIZE / DEV_BSIZE; ++i) { 2254 if (i == (PAGE_SIZE / DEV_BSIZE) || 2255 (m->valid & (1 << i)) 2256 ) { 2257 if (i > b) { 2258 pmap_zero_page_area(m, 2259 b << DEV_BSHIFT, (i - b) << DEV_BSHIFT); 2260 } 2261 b = i + 1; 2262 } 2263 } 2264 2265 /* 2266 * setvalid is TRUE when we can safely set the zero'd areas 2267 * as being valid. We can do this if there are no cache consistancy 2268 * issues. e.g. it is ok to do with UFS, but not ok to do with NFS. 2269 */ 2270 if (setvalid) 2271 m->valid = VM_PAGE_BITS_ALL; 2272 } 2273 2274 /* 2275 * vm_page_is_valid: 2276 * 2277 * Is (partial) page valid? Note that the case where size == 0 2278 * will return FALSE in the degenerate case where the page is 2279 * entirely invalid, and TRUE otherwise. 2280 * 2281 * May not block. 2282 */ 2283 int 2284 vm_page_is_valid(vm_page_t m, int base, int size) 2285 { 2286 int bits = vm_page_bits(base, size); 2287 2288 VM_OBJECT_LOCK_ASSERT(m->object, MA_OWNED); 2289 if (m->valid && ((m->valid & bits) == bits)) 2290 return 1; 2291 else 2292 return 0; 2293 } 2294 2295 /* 2296 * update dirty bits from pmap/mmu. May not block. 2297 */ 2298 void 2299 vm_page_test_dirty(vm_page_t m) 2300 { 2301 2302 VM_OBJECT_LOCK_ASSERT(m->object, MA_OWNED); 2303 if (m->dirty != VM_PAGE_BITS_ALL && pmap_is_modified(m)) 2304 vm_page_dirty(m); 2305 } 2306 2307 int so_zerocp_fullpage = 0; 2308 2309 /* 2310 * Replace the given page with a copy. The copied page assumes 2311 * the portion of the given page's "wire_count" that is not the 2312 * responsibility of this copy-on-write mechanism. 2313 * 2314 * The object containing the given page must have a non-zero 2315 * paging-in-progress count and be locked. 2316 */ 2317 void 2318 vm_page_cowfault(vm_page_t m) 2319 { 2320 vm_page_t mnew; 2321 vm_object_t object; 2322 vm_pindex_t pindex; 2323 2324 mtx_assert(&vm_page_queue_mtx, MA_NOTOWNED); 2325 vm_page_lock_assert(m, MA_OWNED); 2326 object = m->object; 2327 VM_OBJECT_LOCK_ASSERT(object, MA_OWNED); 2328 KASSERT(object->paging_in_progress != 0, 2329 ("vm_page_cowfault: object %p's paging-in-progress count is zero.", 2330 object)); 2331 pindex = m->pindex; 2332 2333 retry_alloc: 2334 pmap_remove_all(m); 2335 vm_page_remove(m); 2336 mnew = vm_page_alloc(object, pindex, VM_ALLOC_NORMAL | VM_ALLOC_NOBUSY); 2337 if (mnew == NULL) { 2338 vm_page_insert(m, object, pindex); 2339 vm_page_unlock(m); 2340 VM_OBJECT_UNLOCK(object); 2341 VM_WAIT; 2342 VM_OBJECT_LOCK(object); 2343 if (m == vm_page_lookup(object, pindex)) { 2344 vm_page_lock(m); 2345 goto retry_alloc; 2346 } else { 2347 /* 2348 * Page disappeared during the wait. 2349 */ 2350 return; 2351 } 2352 } 2353 2354 if (m->cow == 0) { 2355 /* 2356 * check to see if we raced with an xmit complete when 2357 * waiting to allocate a page. If so, put things back 2358 * the way they were 2359 */ 2360 vm_page_unlock(m); 2361 vm_page_lock(mnew); 2362 vm_page_free(mnew); 2363 vm_page_unlock(mnew); 2364 vm_page_insert(m, object, pindex); 2365 } else { /* clear COW & copy page */ 2366 if (!so_zerocp_fullpage) 2367 pmap_copy_page(m, mnew); 2368 mnew->valid = VM_PAGE_BITS_ALL; 2369 vm_page_dirty(mnew); 2370 mnew->wire_count = m->wire_count - m->cow; 2371 m->wire_count = m->cow; 2372 vm_page_unlock(m); 2373 } 2374 } 2375 2376 void 2377 vm_page_cowclear(vm_page_t m) 2378 { 2379 2380 vm_page_lock_assert(m, MA_OWNED); 2381 if (m->cow) { 2382 m->cow--; 2383 /* 2384 * let vm_fault add back write permission lazily 2385 */ 2386 } 2387 /* 2388 * sf_buf_free() will free the page, so we needn't do it here 2389 */ 2390 } 2391 2392 int 2393 vm_page_cowsetup(vm_page_t m) 2394 { 2395 2396 vm_page_lock_assert(m, MA_OWNED); 2397 if ((m->flags & (PG_FICTITIOUS | PG_UNMANAGED)) != 0 || 2398 m->cow == USHRT_MAX - 1 || !VM_OBJECT_TRYLOCK(m->object)) 2399 return (EBUSY); 2400 m->cow++; 2401 pmap_remove_write(m); 2402 VM_OBJECT_UNLOCK(m->object); 2403 return (0); 2404 } 2405 2406 #include "opt_ddb.h" 2407 #ifdef DDB 2408 #include <sys/kernel.h> 2409 2410 #include <ddb/ddb.h> 2411 2412 DB_SHOW_COMMAND(page, vm_page_print_page_info) 2413 { 2414 db_printf("cnt.v_free_count: %d\n", cnt.v_free_count); 2415 db_printf("cnt.v_cache_count: %d\n", cnt.v_cache_count); 2416 db_printf("cnt.v_inactive_count: %d\n", cnt.v_inactive_count); 2417 db_printf("cnt.v_active_count: %d\n", cnt.v_active_count); 2418 db_printf("cnt.v_wire_count: %d\n", cnt.v_wire_count); 2419 db_printf("cnt.v_free_reserved: %d\n", cnt.v_free_reserved); 2420 db_printf("cnt.v_free_min: %d\n", cnt.v_free_min); 2421 db_printf("cnt.v_free_target: %d\n", cnt.v_free_target); 2422 db_printf("cnt.v_cache_min: %d\n", cnt.v_cache_min); 2423 db_printf("cnt.v_inactive_target: %d\n", cnt.v_inactive_target); 2424 } 2425 2426 DB_SHOW_COMMAND(pageq, vm_page_print_pageq_info) 2427 { 2428 2429 db_printf("PQ_FREE:"); 2430 db_printf(" %d", cnt.v_free_count); 2431 db_printf("\n"); 2432 2433 db_printf("PQ_CACHE:"); 2434 db_printf(" %d", cnt.v_cache_count); 2435 db_printf("\n"); 2436 2437 db_printf("PQ_ACTIVE: %d, PQ_INACTIVE: %d\n", 2438 *vm_page_queues[PQ_ACTIVE].cnt, 2439 *vm_page_queues[PQ_INACTIVE].cnt); 2440 } 2441 #endif /* DDB */ 2442