1 /*- 2 * Copyright (c) 1991 Regents of the University of California. 3 * All rights reserved. 4 * Copyright (c) 1998 Matthew Dillon. All Rights Reserved. 5 * 6 * This code is derived from software contributed to Berkeley by 7 * The Mach Operating System project at Carnegie-Mellon University. 8 * 9 * Redistribution and use in source and binary forms, with or without 10 * modification, are permitted provided that the following conditions 11 * are met: 12 * 1. Redistributions of source code must retain the above copyright 13 * notice, this list of conditions and the following disclaimer. 14 * 2. Redistributions in binary form must reproduce the above copyright 15 * notice, this list of conditions and the following disclaimer in the 16 * documentation and/or other materials provided with the distribution. 17 * 4. Neither the name of the University nor the names of its contributors 18 * may be used to endorse or promote products derived from this software 19 * without specific prior written permission. 20 * 21 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 22 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 23 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 24 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 25 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 26 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 27 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 28 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 29 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 30 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 31 * SUCH DAMAGE. 32 * 33 * from: @(#)vm_page.c 7.4 (Berkeley) 5/7/91 34 */ 35 36 /*- 37 * Copyright (c) 1987, 1990 Carnegie-Mellon University. 38 * All rights reserved. 39 * 40 * Authors: Avadis Tevanian, Jr., Michael Wayne Young 41 * 42 * Permission to use, copy, modify and distribute this software and 43 * its documentation is hereby granted, provided that both the copyright 44 * notice and this permission notice appear in all copies of the 45 * software, derivative works or modified versions, and any portions 46 * thereof, and that both notices appear in supporting documentation. 47 * 48 * CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS" 49 * CONDITION. CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND 50 * FOR ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE. 51 * 52 * Carnegie Mellon requests users of this software to return to 53 * 54 * Software Distribution Coordinator or Software.Distribution@CS.CMU.EDU 55 * School of Computer Science 56 * Carnegie Mellon University 57 * Pittsburgh PA 15213-3890 58 * 59 * any improvements or extensions that they make and grant Carnegie the 60 * rights to redistribute these changes. 61 */ 62 63 /* 64 * GENERAL RULES ON VM_PAGE MANIPULATION 65 * 66 * - A page queue lock is required when adding or removing a page from a 67 * page queue regardless of other locks or the busy state of a page. 68 * 69 * * In general, no thread besides the page daemon can acquire or 70 * hold more than one page queue lock at a time. 71 * 72 * * The page daemon can acquire and hold any pair of page queue 73 * locks in any order. 74 * 75 * - The object lock is required when inserting or removing 76 * pages from an object (vm_page_insert() or vm_page_remove()). 77 * 78 */ 79 80 /* 81 * Resident memory management module. 82 */ 83 84 #include <sys/cdefs.h> 85 __FBSDID("$FreeBSD$"); 86 87 #include "opt_vm.h" 88 89 #include <sys/param.h> 90 #include <sys/systm.h> 91 #include <sys/lock.h> 92 #include <sys/kernel.h> 93 #include <sys/limits.h> 94 #include <sys/malloc.h> 95 #include <sys/mman.h> 96 #include <sys/msgbuf.h> 97 #include <sys/mutex.h> 98 #include <sys/proc.h> 99 #include <sys/rwlock.h> 100 #include <sys/sysctl.h> 101 #include <sys/vmmeter.h> 102 #include <sys/vnode.h> 103 104 #include <vm/vm.h> 105 #include <vm/pmap.h> 106 #include <vm/vm_param.h> 107 #include <vm/vm_kern.h> 108 #include <vm/vm_object.h> 109 #include <vm/vm_page.h> 110 #include <vm/vm_pageout.h> 111 #include <vm/vm_pager.h> 112 #include <vm/vm_phys.h> 113 #include <vm/vm_radix.h> 114 #include <vm/vm_reserv.h> 115 #include <vm/vm_extern.h> 116 #include <vm/uma.h> 117 #include <vm/uma_int.h> 118 119 #include <machine/md_var.h> 120 121 /* 122 * Associated with page of user-allocatable memory is a 123 * page structure. 124 */ 125 126 struct vm_domain vm_dom[MAXMEMDOM]; 127 struct mtx_padalign vm_page_queue_free_mtx; 128 129 struct mtx_padalign pa_lock[PA_LOCK_COUNT]; 130 131 vm_page_t vm_page_array; 132 long vm_page_array_size; 133 long first_page; 134 int vm_page_zero_count; 135 136 static int boot_pages = UMA_BOOT_PAGES; 137 SYSCTL_INT(_vm, OID_AUTO, boot_pages, CTLFLAG_RDTUN, &boot_pages, 0, 138 "number of pages allocated for bootstrapping the VM system"); 139 140 static int pa_tryrelock_restart; 141 SYSCTL_INT(_vm, OID_AUTO, tryrelock_restart, CTLFLAG_RD, 142 &pa_tryrelock_restart, 0, "Number of tryrelock restarts"); 143 144 static uma_zone_t fakepg_zone; 145 146 static struct vnode *vm_page_alloc_init(vm_page_t m); 147 static void vm_page_cache_turn_free(vm_page_t m); 148 static void vm_page_clear_dirty_mask(vm_page_t m, vm_page_bits_t pagebits); 149 static void vm_page_enqueue(uint8_t queue, vm_page_t m); 150 static void vm_page_init_fakepg(void *dummy); 151 static int vm_page_insert_after(vm_page_t m, vm_object_t object, 152 vm_pindex_t pindex, vm_page_t mpred); 153 static void vm_page_insert_radixdone(vm_page_t m, vm_object_t object, 154 vm_page_t mpred); 155 156 SYSINIT(vm_page, SI_SUB_VM, SI_ORDER_SECOND, vm_page_init_fakepg, NULL); 157 158 static void 159 vm_page_init_fakepg(void *dummy) 160 { 161 162 fakepg_zone = uma_zcreate("fakepg", sizeof(struct vm_page), NULL, NULL, 163 NULL, NULL, UMA_ALIGN_PTR, UMA_ZONE_NOFREE | UMA_ZONE_VM); 164 } 165 166 /* Make sure that u_long is at least 64 bits when PAGE_SIZE is 32K. */ 167 #if PAGE_SIZE == 32768 168 #ifdef CTASSERT 169 CTASSERT(sizeof(u_long) >= 8); 170 #endif 171 #endif 172 173 /* 174 * Try to acquire a physical address lock while a pmap is locked. If we 175 * fail to trylock we unlock and lock the pmap directly and cache the 176 * locked pa in *locked. The caller should then restart their loop in case 177 * the virtual to physical mapping has changed. 178 */ 179 int 180 vm_page_pa_tryrelock(pmap_t pmap, vm_paddr_t pa, vm_paddr_t *locked) 181 { 182 vm_paddr_t lockpa; 183 184 lockpa = *locked; 185 *locked = pa; 186 if (lockpa) { 187 PA_LOCK_ASSERT(lockpa, MA_OWNED); 188 if (PA_LOCKPTR(pa) == PA_LOCKPTR(lockpa)) 189 return (0); 190 PA_UNLOCK(lockpa); 191 } 192 if (PA_TRYLOCK(pa)) 193 return (0); 194 PMAP_UNLOCK(pmap); 195 atomic_add_int(&pa_tryrelock_restart, 1); 196 PA_LOCK(pa); 197 PMAP_LOCK(pmap); 198 return (EAGAIN); 199 } 200 201 /* 202 * vm_set_page_size: 203 * 204 * Sets the page size, perhaps based upon the memory 205 * size. Must be called before any use of page-size 206 * dependent functions. 207 */ 208 void 209 vm_set_page_size(void) 210 { 211 if (vm_cnt.v_page_size == 0) 212 vm_cnt.v_page_size = PAGE_SIZE; 213 if (((vm_cnt.v_page_size - 1) & vm_cnt.v_page_size) != 0) 214 panic("vm_set_page_size: page size not a power of two"); 215 } 216 217 /* 218 * vm_page_blacklist_lookup: 219 * 220 * See if a physical address in this page has been listed 221 * in the blacklist tunable. Entries in the tunable are 222 * separated by spaces or commas. If an invalid integer is 223 * encountered then the rest of the string is skipped. 224 */ 225 static int 226 vm_page_blacklist_lookup(char *list, vm_paddr_t pa) 227 { 228 vm_paddr_t bad; 229 char *cp, *pos; 230 231 for (pos = list; *pos != '\0'; pos = cp) { 232 bad = strtoq(pos, &cp, 0); 233 if (*cp != '\0') { 234 if (*cp == ' ' || *cp == ',') { 235 cp++; 236 if (cp == pos) 237 continue; 238 } else 239 break; 240 } 241 if (pa == trunc_page(bad)) 242 return (1); 243 } 244 return (0); 245 } 246 247 static void 248 vm_page_domain_init(struct vm_domain *vmd) 249 { 250 struct vm_pagequeue *pq; 251 int i; 252 253 *__DECONST(char **, &vmd->vmd_pagequeues[PQ_INACTIVE].pq_name) = 254 "vm inactive pagequeue"; 255 *__DECONST(int **, &vmd->vmd_pagequeues[PQ_INACTIVE].pq_vcnt) = 256 &vm_cnt.v_inactive_count; 257 *__DECONST(char **, &vmd->vmd_pagequeues[PQ_ACTIVE].pq_name) = 258 "vm active pagequeue"; 259 *__DECONST(int **, &vmd->vmd_pagequeues[PQ_ACTIVE].pq_vcnt) = 260 &vm_cnt.v_active_count; 261 vmd->vmd_page_count = 0; 262 vmd->vmd_free_count = 0; 263 vmd->vmd_segs = 0; 264 vmd->vmd_oom = FALSE; 265 vmd->vmd_pass = 0; 266 for (i = 0; i < PQ_COUNT; i++) { 267 pq = &vmd->vmd_pagequeues[i]; 268 TAILQ_INIT(&pq->pq_pl); 269 mtx_init(&pq->pq_mutex, pq->pq_name, "vm pagequeue", 270 MTX_DEF | MTX_DUPOK); 271 } 272 } 273 274 /* 275 * vm_page_startup: 276 * 277 * Initializes the resident memory module. 278 * 279 * Allocates memory for the page cells, and 280 * for the object/offset-to-page hash table headers. 281 * Each page cell is initialized and placed on the free list. 282 */ 283 vm_offset_t 284 vm_page_startup(vm_offset_t vaddr) 285 { 286 vm_offset_t mapped; 287 vm_paddr_t page_range; 288 vm_paddr_t new_end; 289 int i; 290 vm_paddr_t pa; 291 vm_paddr_t last_pa; 292 char *list; 293 vm_paddr_t end; 294 vm_paddr_t biggestsize; 295 vm_paddr_t low_water, high_water; 296 int biggestone; 297 298 biggestsize = 0; 299 biggestone = 0; 300 vaddr = round_page(vaddr); 301 302 for (i = 0; phys_avail[i + 1]; i += 2) { 303 phys_avail[i] = round_page(phys_avail[i]); 304 phys_avail[i + 1] = trunc_page(phys_avail[i + 1]); 305 } 306 307 #ifdef XEN 308 /* 309 * There is no obvious reason why i386 PV Xen needs vm_page structs 310 * created for these pseudo-physical addresses. XXX 311 */ 312 vm_phys_add_seg(0, phys_avail[0]); 313 #endif 314 315 low_water = phys_avail[0]; 316 high_water = phys_avail[1]; 317 318 for (i = 0; i < vm_phys_nsegs; i++) { 319 if (vm_phys_segs[i].start < low_water) 320 low_water = vm_phys_segs[i].start; 321 if (vm_phys_segs[i].end > high_water) 322 high_water = vm_phys_segs[i].end; 323 } 324 for (i = 0; phys_avail[i + 1]; i += 2) { 325 vm_paddr_t size = phys_avail[i + 1] - phys_avail[i]; 326 327 if (size > biggestsize) { 328 biggestone = i; 329 biggestsize = size; 330 } 331 if (phys_avail[i] < low_water) 332 low_water = phys_avail[i]; 333 if (phys_avail[i + 1] > high_water) 334 high_water = phys_avail[i + 1]; 335 } 336 337 end = phys_avail[biggestone+1]; 338 339 /* 340 * Initialize the page and queue locks. 341 */ 342 mtx_init(&vm_page_queue_free_mtx, "vm page free queue", NULL, MTX_DEF); 343 for (i = 0; i < PA_LOCK_COUNT; i++) 344 mtx_init(&pa_lock[i], "vm page", NULL, MTX_DEF); 345 for (i = 0; i < vm_ndomains; i++) 346 vm_page_domain_init(&vm_dom[i]); 347 348 /* 349 * Allocate memory for use when boot strapping the kernel memory 350 * allocator. 351 */ 352 new_end = end - (boot_pages * UMA_SLAB_SIZE); 353 new_end = trunc_page(new_end); 354 mapped = pmap_map(&vaddr, new_end, end, 355 VM_PROT_READ | VM_PROT_WRITE); 356 bzero((void *)mapped, end - new_end); 357 uma_startup((void *)mapped, boot_pages); 358 359 #if defined(__amd64__) || defined(__i386__) || defined(__arm__) || \ 360 defined(__mips__) 361 /* 362 * Allocate a bitmap to indicate that a random physical page 363 * needs to be included in a minidump. 364 * 365 * The amd64 port needs this to indicate which direct map pages 366 * need to be dumped, via calls to dump_add_page()/dump_drop_page(). 367 * 368 * However, i386 still needs this workspace internally within the 369 * minidump code. In theory, they are not needed on i386, but are 370 * included should the sf_buf code decide to use them. 371 */ 372 last_pa = 0; 373 for (i = 0; dump_avail[i + 1] != 0; i += 2) 374 if (dump_avail[i + 1] > last_pa) 375 last_pa = dump_avail[i + 1]; 376 page_range = last_pa / PAGE_SIZE; 377 vm_page_dump_size = round_page(roundup2(page_range, NBBY) / NBBY); 378 new_end -= vm_page_dump_size; 379 vm_page_dump = (void *)(uintptr_t)pmap_map(&vaddr, new_end, 380 new_end + vm_page_dump_size, VM_PROT_READ | VM_PROT_WRITE); 381 bzero((void *)vm_page_dump, vm_page_dump_size); 382 #endif 383 #ifdef __amd64__ 384 /* 385 * Request that the physical pages underlying the message buffer be 386 * included in a crash dump. Since the message buffer is accessed 387 * through the direct map, they are not automatically included. 388 */ 389 pa = DMAP_TO_PHYS((vm_offset_t)msgbufp->msg_ptr); 390 last_pa = pa + round_page(msgbufsize); 391 while (pa < last_pa) { 392 dump_add_page(pa); 393 pa += PAGE_SIZE; 394 } 395 #endif 396 /* 397 * Compute the number of pages of memory that will be available for 398 * use (taking into account the overhead of a page structure per 399 * page). 400 */ 401 first_page = low_water / PAGE_SIZE; 402 #ifdef VM_PHYSSEG_SPARSE 403 page_range = 0; 404 for (i = 0; i < vm_phys_nsegs; i++) { 405 page_range += atop(vm_phys_segs[i].end - 406 vm_phys_segs[i].start); 407 } 408 for (i = 0; phys_avail[i + 1] != 0; i += 2) 409 page_range += atop(phys_avail[i + 1] - phys_avail[i]); 410 #elif defined(VM_PHYSSEG_DENSE) 411 page_range = high_water / PAGE_SIZE - first_page; 412 #else 413 #error "Either VM_PHYSSEG_DENSE or VM_PHYSSEG_SPARSE must be defined." 414 #endif 415 end = new_end; 416 417 /* 418 * Reserve an unmapped guard page to trap access to vm_page_array[-1]. 419 */ 420 vaddr += PAGE_SIZE; 421 422 /* 423 * Initialize the mem entry structures now, and put them in the free 424 * queue. 425 */ 426 new_end = trunc_page(end - page_range * sizeof(struct vm_page)); 427 mapped = pmap_map(&vaddr, new_end, end, 428 VM_PROT_READ | VM_PROT_WRITE); 429 vm_page_array = (vm_page_t) mapped; 430 #if VM_NRESERVLEVEL > 0 431 /* 432 * Allocate memory for the reservation management system's data 433 * structures. 434 */ 435 new_end = vm_reserv_startup(&vaddr, new_end, high_water); 436 #endif 437 #if defined(__amd64__) || defined(__mips__) 438 /* 439 * pmap_map on amd64 and mips can come out of the direct-map, not kvm 440 * like i386, so the pages must be tracked for a crashdump to include 441 * this data. This includes the vm_page_array and the early UMA 442 * bootstrap pages. 443 */ 444 for (pa = new_end; pa < phys_avail[biggestone + 1]; pa += PAGE_SIZE) 445 dump_add_page(pa); 446 #endif 447 phys_avail[biggestone + 1] = new_end; 448 449 /* 450 * Add physical memory segments corresponding to the available 451 * physical pages. 452 */ 453 for (i = 0; phys_avail[i + 1] != 0; i += 2) 454 vm_phys_add_seg(phys_avail[i], phys_avail[i + 1]); 455 456 /* 457 * Clear all of the page structures 458 */ 459 bzero((caddr_t) vm_page_array, page_range * sizeof(struct vm_page)); 460 for (i = 0; i < page_range; i++) 461 vm_page_array[i].order = VM_NFREEORDER; 462 vm_page_array_size = page_range; 463 464 /* 465 * Initialize the physical memory allocator. 466 */ 467 vm_phys_init(); 468 469 /* 470 * Add every available physical page that is not blacklisted to 471 * the free lists. 472 */ 473 vm_cnt.v_page_count = 0; 474 vm_cnt.v_free_count = 0; 475 list = kern_getenv("vm.blacklist"); 476 for (i = 0; phys_avail[i + 1] != 0; i += 2) { 477 pa = phys_avail[i]; 478 last_pa = phys_avail[i + 1]; 479 while (pa < last_pa) { 480 if (list != NULL && 481 vm_page_blacklist_lookup(list, pa)) 482 printf("Skipping page with pa 0x%jx\n", 483 (uintmax_t)pa); 484 else 485 vm_phys_add_page(pa); 486 pa += PAGE_SIZE; 487 } 488 } 489 freeenv(list); 490 #if VM_NRESERVLEVEL > 0 491 /* 492 * Initialize the reservation management system. 493 */ 494 vm_reserv_init(); 495 #endif 496 return (vaddr); 497 } 498 499 void 500 vm_page_reference(vm_page_t m) 501 { 502 503 vm_page_aflag_set(m, PGA_REFERENCED); 504 } 505 506 /* 507 * vm_page_busy_downgrade: 508 * 509 * Downgrade an exclusive busy page into a single shared busy page. 510 */ 511 void 512 vm_page_busy_downgrade(vm_page_t m) 513 { 514 u_int x; 515 516 vm_page_assert_xbusied(m); 517 518 for (;;) { 519 x = m->busy_lock; 520 x &= VPB_BIT_WAITERS; 521 if (atomic_cmpset_rel_int(&m->busy_lock, 522 VPB_SINGLE_EXCLUSIVER | x, VPB_SHARERS_WORD(1) | x)) 523 break; 524 } 525 } 526 527 /* 528 * vm_page_sbusied: 529 * 530 * Return a positive value if the page is shared busied, 0 otherwise. 531 */ 532 int 533 vm_page_sbusied(vm_page_t m) 534 { 535 u_int x; 536 537 x = m->busy_lock; 538 return ((x & VPB_BIT_SHARED) != 0 && x != VPB_UNBUSIED); 539 } 540 541 /* 542 * vm_page_sunbusy: 543 * 544 * Shared unbusy a page. 545 */ 546 void 547 vm_page_sunbusy(vm_page_t m) 548 { 549 u_int x; 550 551 vm_page_assert_sbusied(m); 552 553 for (;;) { 554 x = m->busy_lock; 555 if (VPB_SHARERS(x) > 1) { 556 if (atomic_cmpset_int(&m->busy_lock, x, 557 x - VPB_ONE_SHARER)) 558 break; 559 continue; 560 } 561 if ((x & VPB_BIT_WAITERS) == 0) { 562 KASSERT(x == VPB_SHARERS_WORD(1), 563 ("vm_page_sunbusy: invalid lock state")); 564 if (atomic_cmpset_int(&m->busy_lock, 565 VPB_SHARERS_WORD(1), VPB_UNBUSIED)) 566 break; 567 continue; 568 } 569 KASSERT(x == (VPB_SHARERS_WORD(1) | VPB_BIT_WAITERS), 570 ("vm_page_sunbusy: invalid lock state for waiters")); 571 572 vm_page_lock(m); 573 if (!atomic_cmpset_int(&m->busy_lock, x, VPB_UNBUSIED)) { 574 vm_page_unlock(m); 575 continue; 576 } 577 wakeup(m); 578 vm_page_unlock(m); 579 break; 580 } 581 } 582 583 /* 584 * vm_page_busy_sleep: 585 * 586 * Sleep and release the page lock, using the page pointer as wchan. 587 * This is used to implement the hard-path of busying mechanism. 588 * 589 * The given page must be locked. 590 */ 591 void 592 vm_page_busy_sleep(vm_page_t m, const char *wmesg) 593 { 594 u_int x; 595 596 vm_page_lock_assert(m, MA_OWNED); 597 598 x = m->busy_lock; 599 if (x == VPB_UNBUSIED) { 600 vm_page_unlock(m); 601 return; 602 } 603 if ((x & VPB_BIT_WAITERS) == 0 && 604 !atomic_cmpset_int(&m->busy_lock, x, x | VPB_BIT_WAITERS)) { 605 vm_page_unlock(m); 606 return; 607 } 608 msleep(m, vm_page_lockptr(m), PVM | PDROP, wmesg, 0); 609 } 610 611 /* 612 * vm_page_trysbusy: 613 * 614 * Try to shared busy a page. 615 * If the operation succeeds 1 is returned otherwise 0. 616 * The operation never sleeps. 617 */ 618 int 619 vm_page_trysbusy(vm_page_t m) 620 { 621 u_int x; 622 623 for (;;) { 624 x = m->busy_lock; 625 if ((x & VPB_BIT_SHARED) == 0) 626 return (0); 627 if (atomic_cmpset_acq_int(&m->busy_lock, x, x + VPB_ONE_SHARER)) 628 return (1); 629 } 630 } 631 632 /* 633 * vm_page_xunbusy_hard: 634 * 635 * Called after the first try the exclusive unbusy of a page failed. 636 * It is assumed that the waiters bit is on. 637 */ 638 void 639 vm_page_xunbusy_hard(vm_page_t m) 640 { 641 642 vm_page_assert_xbusied(m); 643 644 vm_page_lock(m); 645 atomic_store_rel_int(&m->busy_lock, VPB_UNBUSIED); 646 wakeup(m); 647 vm_page_unlock(m); 648 } 649 650 /* 651 * vm_page_flash: 652 * 653 * Wakeup anyone waiting for the page. 654 * The ownership bits do not change. 655 * 656 * The given page must be locked. 657 */ 658 void 659 vm_page_flash(vm_page_t m) 660 { 661 u_int x; 662 663 vm_page_lock_assert(m, MA_OWNED); 664 665 for (;;) { 666 x = m->busy_lock; 667 if ((x & VPB_BIT_WAITERS) == 0) 668 return; 669 if (atomic_cmpset_int(&m->busy_lock, x, 670 x & (~VPB_BIT_WAITERS))) 671 break; 672 } 673 wakeup(m); 674 } 675 676 /* 677 * Keep page from being freed by the page daemon 678 * much of the same effect as wiring, except much lower 679 * overhead and should be used only for *very* temporary 680 * holding ("wiring"). 681 */ 682 void 683 vm_page_hold(vm_page_t mem) 684 { 685 686 vm_page_lock_assert(mem, MA_OWNED); 687 mem->hold_count++; 688 } 689 690 void 691 vm_page_unhold(vm_page_t mem) 692 { 693 694 vm_page_lock_assert(mem, MA_OWNED); 695 KASSERT(mem->hold_count >= 1, ("vm_page_unhold: hold count < 0!!!")); 696 --mem->hold_count; 697 if (mem->hold_count == 0 && (mem->flags & PG_UNHOLDFREE) != 0) 698 vm_page_free_toq(mem); 699 } 700 701 /* 702 * vm_page_unhold_pages: 703 * 704 * Unhold each of the pages that is referenced by the given array. 705 */ 706 void 707 vm_page_unhold_pages(vm_page_t *ma, int count) 708 { 709 struct mtx *mtx, *new_mtx; 710 711 mtx = NULL; 712 for (; count != 0; count--) { 713 /* 714 * Avoid releasing and reacquiring the same page lock. 715 */ 716 new_mtx = vm_page_lockptr(*ma); 717 if (mtx != new_mtx) { 718 if (mtx != NULL) 719 mtx_unlock(mtx); 720 mtx = new_mtx; 721 mtx_lock(mtx); 722 } 723 vm_page_unhold(*ma); 724 ma++; 725 } 726 if (mtx != NULL) 727 mtx_unlock(mtx); 728 } 729 730 vm_page_t 731 PHYS_TO_VM_PAGE(vm_paddr_t pa) 732 { 733 vm_page_t m; 734 735 #ifdef VM_PHYSSEG_SPARSE 736 m = vm_phys_paddr_to_vm_page(pa); 737 if (m == NULL) 738 m = vm_phys_fictitious_to_vm_page(pa); 739 return (m); 740 #elif defined(VM_PHYSSEG_DENSE) 741 long pi; 742 743 pi = atop(pa); 744 if (pi >= first_page && (pi - first_page) < vm_page_array_size) { 745 m = &vm_page_array[pi - first_page]; 746 return (m); 747 } 748 return (vm_phys_fictitious_to_vm_page(pa)); 749 #else 750 #error "Either VM_PHYSSEG_DENSE or VM_PHYSSEG_SPARSE must be defined." 751 #endif 752 } 753 754 /* 755 * vm_page_getfake: 756 * 757 * Create a fictitious page with the specified physical address and 758 * memory attribute. The memory attribute is the only the machine- 759 * dependent aspect of a fictitious page that must be initialized. 760 */ 761 vm_page_t 762 vm_page_getfake(vm_paddr_t paddr, vm_memattr_t memattr) 763 { 764 vm_page_t m; 765 766 m = uma_zalloc(fakepg_zone, M_WAITOK | M_ZERO); 767 vm_page_initfake(m, paddr, memattr); 768 return (m); 769 } 770 771 void 772 vm_page_initfake(vm_page_t m, vm_paddr_t paddr, vm_memattr_t memattr) 773 { 774 775 if ((m->flags & PG_FICTITIOUS) != 0) { 776 /* 777 * The page's memattr might have changed since the 778 * previous initialization. Update the pmap to the 779 * new memattr. 780 */ 781 goto memattr; 782 } 783 m->phys_addr = paddr; 784 m->queue = PQ_NONE; 785 /* Fictitious pages don't use "segind". */ 786 m->flags = PG_FICTITIOUS; 787 /* Fictitious pages don't use "order" or "pool". */ 788 m->oflags = VPO_UNMANAGED; 789 m->busy_lock = VPB_SINGLE_EXCLUSIVER; 790 m->wire_count = 1; 791 pmap_page_init(m); 792 memattr: 793 pmap_page_set_memattr(m, memattr); 794 } 795 796 /* 797 * vm_page_putfake: 798 * 799 * Release a fictitious page. 800 */ 801 void 802 vm_page_putfake(vm_page_t m) 803 { 804 805 KASSERT((m->oflags & VPO_UNMANAGED) != 0, ("managed %p", m)); 806 KASSERT((m->flags & PG_FICTITIOUS) != 0, 807 ("vm_page_putfake: bad page %p", m)); 808 uma_zfree(fakepg_zone, m); 809 } 810 811 /* 812 * vm_page_updatefake: 813 * 814 * Update the given fictitious page to the specified physical address and 815 * memory attribute. 816 */ 817 void 818 vm_page_updatefake(vm_page_t m, vm_paddr_t paddr, vm_memattr_t memattr) 819 { 820 821 KASSERT((m->flags & PG_FICTITIOUS) != 0, 822 ("vm_page_updatefake: bad page %p", m)); 823 m->phys_addr = paddr; 824 pmap_page_set_memattr(m, memattr); 825 } 826 827 /* 828 * vm_page_free: 829 * 830 * Free a page. 831 */ 832 void 833 vm_page_free(vm_page_t m) 834 { 835 836 m->flags &= ~PG_ZERO; 837 vm_page_free_toq(m); 838 } 839 840 /* 841 * vm_page_free_zero: 842 * 843 * Free a page to the zerod-pages queue 844 */ 845 void 846 vm_page_free_zero(vm_page_t m) 847 { 848 849 m->flags |= PG_ZERO; 850 vm_page_free_toq(m); 851 } 852 853 /* 854 * Unbusy and handle the page queueing for a page from the VOP_GETPAGES() 855 * array which is not the request page. 856 */ 857 void 858 vm_page_readahead_finish(vm_page_t m) 859 { 860 861 if (m->valid != 0) { 862 /* 863 * Since the page is not the requested page, whether 864 * it should be activated or deactivated is not 865 * obvious. Empirical results have shown that 866 * deactivating the page is usually the best choice, 867 * unless the page is wanted by another thread. 868 */ 869 vm_page_lock(m); 870 if ((m->busy_lock & VPB_BIT_WAITERS) != 0) 871 vm_page_activate(m); 872 else 873 vm_page_deactivate(m); 874 vm_page_unlock(m); 875 vm_page_xunbusy(m); 876 } else { 877 /* 878 * Free the completely invalid page. Such page state 879 * occurs due to the short read operation which did 880 * not covered our page at all, or in case when a read 881 * error happens. 882 */ 883 vm_page_lock(m); 884 vm_page_free(m); 885 vm_page_unlock(m); 886 } 887 } 888 889 /* 890 * vm_page_sleep_if_busy: 891 * 892 * Sleep and release the page queues lock if the page is busied. 893 * Returns TRUE if the thread slept. 894 * 895 * The given page must be unlocked and object containing it must 896 * be locked. 897 */ 898 int 899 vm_page_sleep_if_busy(vm_page_t m, const char *msg) 900 { 901 vm_object_t obj; 902 903 vm_page_lock_assert(m, MA_NOTOWNED); 904 VM_OBJECT_ASSERT_WLOCKED(m->object); 905 906 if (vm_page_busied(m)) { 907 /* 908 * The page-specific object must be cached because page 909 * identity can change during the sleep, causing the 910 * re-lock of a different object. 911 * It is assumed that a reference to the object is already 912 * held by the callers. 913 */ 914 obj = m->object; 915 vm_page_lock(m); 916 VM_OBJECT_WUNLOCK(obj); 917 vm_page_busy_sleep(m, msg); 918 VM_OBJECT_WLOCK(obj); 919 return (TRUE); 920 } 921 return (FALSE); 922 } 923 924 /* 925 * vm_page_dirty_KBI: [ internal use only ] 926 * 927 * Set all bits in the page's dirty field. 928 * 929 * The object containing the specified page must be locked if the 930 * call is made from the machine-independent layer. 931 * 932 * See vm_page_clear_dirty_mask(). 933 * 934 * This function should only be called by vm_page_dirty(). 935 */ 936 void 937 vm_page_dirty_KBI(vm_page_t m) 938 { 939 940 /* These assertions refer to this operation by its public name. */ 941 KASSERT((m->flags & PG_CACHED) == 0, 942 ("vm_page_dirty: page in cache!")); 943 KASSERT(m->valid == VM_PAGE_BITS_ALL, 944 ("vm_page_dirty: page is invalid!")); 945 m->dirty = VM_PAGE_BITS_ALL; 946 } 947 948 /* 949 * vm_page_insert: [ internal use only ] 950 * 951 * Inserts the given mem entry into the object and object list. 952 * 953 * The object must be locked. 954 */ 955 int 956 vm_page_insert(vm_page_t m, vm_object_t object, vm_pindex_t pindex) 957 { 958 vm_page_t mpred; 959 960 VM_OBJECT_ASSERT_WLOCKED(object); 961 mpred = vm_radix_lookup_le(&object->rtree, pindex); 962 return (vm_page_insert_after(m, object, pindex, mpred)); 963 } 964 965 /* 966 * vm_page_insert_after: 967 * 968 * Inserts the page "m" into the specified object at offset "pindex". 969 * 970 * The page "mpred" must immediately precede the offset "pindex" within 971 * the specified object. 972 * 973 * The object must be locked. 974 */ 975 static int 976 vm_page_insert_after(vm_page_t m, vm_object_t object, vm_pindex_t pindex, 977 vm_page_t mpred) 978 { 979 vm_pindex_t sidx; 980 vm_object_t sobj; 981 vm_page_t msucc; 982 983 VM_OBJECT_ASSERT_WLOCKED(object); 984 KASSERT(m->object == NULL, 985 ("vm_page_insert_after: page already inserted")); 986 if (mpred != NULL) { 987 KASSERT(mpred->object == object, 988 ("vm_page_insert_after: object doesn't contain mpred")); 989 KASSERT(mpred->pindex < pindex, 990 ("vm_page_insert_after: mpred doesn't precede pindex")); 991 msucc = TAILQ_NEXT(mpred, listq); 992 } else 993 msucc = TAILQ_FIRST(&object->memq); 994 if (msucc != NULL) 995 KASSERT(msucc->pindex > pindex, 996 ("vm_page_insert_after: msucc doesn't succeed pindex")); 997 998 /* 999 * Record the object/offset pair in this page 1000 */ 1001 sobj = m->object; 1002 sidx = m->pindex; 1003 m->object = object; 1004 m->pindex = pindex; 1005 1006 /* 1007 * Now link into the object's ordered list of backed pages. 1008 */ 1009 if (vm_radix_insert(&object->rtree, m)) { 1010 m->object = sobj; 1011 m->pindex = sidx; 1012 return (1); 1013 } 1014 vm_page_insert_radixdone(m, object, mpred); 1015 return (0); 1016 } 1017 1018 /* 1019 * vm_page_insert_radixdone: 1020 * 1021 * Complete page "m" insertion into the specified object after the 1022 * radix trie hooking. 1023 * 1024 * The page "mpred" must precede the offset "m->pindex" within the 1025 * specified object. 1026 * 1027 * The object must be locked. 1028 */ 1029 static void 1030 vm_page_insert_radixdone(vm_page_t m, vm_object_t object, vm_page_t mpred) 1031 { 1032 1033 VM_OBJECT_ASSERT_WLOCKED(object); 1034 KASSERT(object != NULL && m->object == object, 1035 ("vm_page_insert_radixdone: page %p has inconsistent object", m)); 1036 if (mpred != NULL) { 1037 KASSERT(mpred->object == object, 1038 ("vm_page_insert_after: object doesn't contain mpred")); 1039 KASSERT(mpred->pindex < m->pindex, 1040 ("vm_page_insert_after: mpred doesn't precede pindex")); 1041 } 1042 1043 if (mpred != NULL) 1044 TAILQ_INSERT_AFTER(&object->memq, mpred, m, listq); 1045 else 1046 TAILQ_INSERT_HEAD(&object->memq, m, listq); 1047 1048 /* 1049 * Show that the object has one more resident page. 1050 */ 1051 object->resident_page_count++; 1052 1053 /* 1054 * Hold the vnode until the last page is released. 1055 */ 1056 if (object->resident_page_count == 1 && object->type == OBJT_VNODE) 1057 vhold(object->handle); 1058 1059 /* 1060 * Since we are inserting a new and possibly dirty page, 1061 * update the object's OBJ_MIGHTBEDIRTY flag. 1062 */ 1063 if (pmap_page_is_write_mapped(m)) 1064 vm_object_set_writeable_dirty(object); 1065 } 1066 1067 /* 1068 * vm_page_remove: 1069 * 1070 * Removes the given mem entry from the object/offset-page 1071 * table and the object page list, but do not invalidate/terminate 1072 * the backing store. 1073 * 1074 * The object must be locked. The page must be locked if it is managed. 1075 */ 1076 void 1077 vm_page_remove(vm_page_t m) 1078 { 1079 vm_object_t object; 1080 boolean_t lockacq; 1081 1082 if ((m->oflags & VPO_UNMANAGED) == 0) 1083 vm_page_lock_assert(m, MA_OWNED); 1084 if ((object = m->object) == NULL) 1085 return; 1086 VM_OBJECT_ASSERT_WLOCKED(object); 1087 if (vm_page_xbusied(m)) { 1088 lockacq = FALSE; 1089 if ((m->oflags & VPO_UNMANAGED) != 0 && 1090 !mtx_owned(vm_page_lockptr(m))) { 1091 lockacq = TRUE; 1092 vm_page_lock(m); 1093 } 1094 vm_page_flash(m); 1095 atomic_store_rel_int(&m->busy_lock, VPB_UNBUSIED); 1096 if (lockacq) 1097 vm_page_unlock(m); 1098 } 1099 1100 /* 1101 * Now remove from the object's list of backed pages. 1102 */ 1103 vm_radix_remove(&object->rtree, m->pindex); 1104 TAILQ_REMOVE(&object->memq, m, listq); 1105 1106 /* 1107 * And show that the object has one fewer resident page. 1108 */ 1109 object->resident_page_count--; 1110 1111 /* 1112 * The vnode may now be recycled. 1113 */ 1114 if (object->resident_page_count == 0 && object->type == OBJT_VNODE) 1115 vdrop(object->handle); 1116 1117 m->object = NULL; 1118 } 1119 1120 /* 1121 * vm_page_lookup: 1122 * 1123 * Returns the page associated with the object/offset 1124 * pair specified; if none is found, NULL is returned. 1125 * 1126 * The object must be locked. 1127 */ 1128 vm_page_t 1129 vm_page_lookup(vm_object_t object, vm_pindex_t pindex) 1130 { 1131 1132 VM_OBJECT_ASSERT_LOCKED(object); 1133 return (vm_radix_lookup(&object->rtree, pindex)); 1134 } 1135 1136 /* 1137 * vm_page_find_least: 1138 * 1139 * Returns the page associated with the object with least pindex 1140 * greater than or equal to the parameter pindex, or NULL. 1141 * 1142 * The object must be locked. 1143 */ 1144 vm_page_t 1145 vm_page_find_least(vm_object_t object, vm_pindex_t pindex) 1146 { 1147 vm_page_t m; 1148 1149 VM_OBJECT_ASSERT_LOCKED(object); 1150 if ((m = TAILQ_FIRST(&object->memq)) != NULL && m->pindex < pindex) 1151 m = vm_radix_lookup_ge(&object->rtree, pindex); 1152 return (m); 1153 } 1154 1155 /* 1156 * Returns the given page's successor (by pindex) within the object if it is 1157 * resident; if none is found, NULL is returned. 1158 * 1159 * The object must be locked. 1160 */ 1161 vm_page_t 1162 vm_page_next(vm_page_t m) 1163 { 1164 vm_page_t next; 1165 1166 VM_OBJECT_ASSERT_WLOCKED(m->object); 1167 if ((next = TAILQ_NEXT(m, listq)) != NULL && 1168 next->pindex != m->pindex + 1) 1169 next = NULL; 1170 return (next); 1171 } 1172 1173 /* 1174 * Returns the given page's predecessor (by pindex) within the object if it is 1175 * resident; if none is found, NULL is returned. 1176 * 1177 * The object must be locked. 1178 */ 1179 vm_page_t 1180 vm_page_prev(vm_page_t m) 1181 { 1182 vm_page_t prev; 1183 1184 VM_OBJECT_ASSERT_WLOCKED(m->object); 1185 if ((prev = TAILQ_PREV(m, pglist, listq)) != NULL && 1186 prev->pindex != m->pindex - 1) 1187 prev = NULL; 1188 return (prev); 1189 } 1190 1191 /* 1192 * Uses the page mnew as a replacement for an existing page at index 1193 * pindex which must be already present in the object. 1194 * 1195 * The existing page must not be on a paging queue. 1196 */ 1197 vm_page_t 1198 vm_page_replace(vm_page_t mnew, vm_object_t object, vm_pindex_t pindex) 1199 { 1200 vm_page_t mold, mpred; 1201 1202 VM_OBJECT_ASSERT_WLOCKED(object); 1203 1204 /* 1205 * This function mostly follows vm_page_insert() and 1206 * vm_page_remove() without the radix, object count and vnode 1207 * dance. Double check such functions for more comments. 1208 */ 1209 mpred = vm_radix_lookup(&object->rtree, pindex); 1210 KASSERT(mpred != NULL, 1211 ("vm_page_replace: replacing page not present with pindex")); 1212 mpred = TAILQ_PREV(mpred, respgs, listq); 1213 if (mpred != NULL) 1214 KASSERT(mpred->pindex < pindex, 1215 ("vm_page_insert_after: mpred doesn't precede pindex")); 1216 1217 mnew->object = object; 1218 mnew->pindex = pindex; 1219 mold = vm_radix_replace(&object->rtree, mnew); 1220 KASSERT(mold->queue == PQ_NONE, 1221 ("vm_page_replace: mold is on a paging queue")); 1222 1223 /* Detach the old page from the resident tailq. */ 1224 TAILQ_REMOVE(&object->memq, mold, listq); 1225 1226 mold->object = NULL; 1227 vm_page_xunbusy(mold); 1228 1229 /* Insert the new page in the resident tailq. */ 1230 if (mpred != NULL) 1231 TAILQ_INSERT_AFTER(&object->memq, mpred, mnew, listq); 1232 else 1233 TAILQ_INSERT_HEAD(&object->memq, mnew, listq); 1234 if (pmap_page_is_write_mapped(mnew)) 1235 vm_object_set_writeable_dirty(object); 1236 return (mold); 1237 } 1238 1239 /* 1240 * vm_page_rename: 1241 * 1242 * Move the given memory entry from its 1243 * current object to the specified target object/offset. 1244 * 1245 * Note: swap associated with the page must be invalidated by the move. We 1246 * have to do this for several reasons: (1) we aren't freeing the 1247 * page, (2) we are dirtying the page, (3) the VM system is probably 1248 * moving the page from object A to B, and will then later move 1249 * the backing store from A to B and we can't have a conflict. 1250 * 1251 * Note: we *always* dirty the page. It is necessary both for the 1252 * fact that we moved it, and because we may be invalidating 1253 * swap. If the page is on the cache, we have to deactivate it 1254 * or vm_page_dirty() will panic. Dirty pages are not allowed 1255 * on the cache. 1256 * 1257 * The objects must be locked. 1258 */ 1259 int 1260 vm_page_rename(vm_page_t m, vm_object_t new_object, vm_pindex_t new_pindex) 1261 { 1262 vm_page_t mpred; 1263 vm_pindex_t opidx; 1264 1265 VM_OBJECT_ASSERT_WLOCKED(new_object); 1266 1267 mpred = vm_radix_lookup_le(&new_object->rtree, new_pindex); 1268 KASSERT(mpred == NULL || mpred->pindex != new_pindex, 1269 ("vm_page_rename: pindex already renamed")); 1270 1271 /* 1272 * Create a custom version of vm_page_insert() which does not depend 1273 * by m_prev and can cheat on the implementation aspects of the 1274 * function. 1275 */ 1276 opidx = m->pindex; 1277 m->pindex = new_pindex; 1278 if (vm_radix_insert(&new_object->rtree, m)) { 1279 m->pindex = opidx; 1280 return (1); 1281 } 1282 1283 /* 1284 * The operation cannot fail anymore. The removal must happen before 1285 * the listq iterator is tainted. 1286 */ 1287 m->pindex = opidx; 1288 vm_page_lock(m); 1289 vm_page_remove(m); 1290 1291 /* Return back to the new pindex to complete vm_page_insert(). */ 1292 m->pindex = new_pindex; 1293 m->object = new_object; 1294 vm_page_unlock(m); 1295 vm_page_insert_radixdone(m, new_object, mpred); 1296 vm_page_dirty(m); 1297 return (0); 1298 } 1299 1300 /* 1301 * Convert all of the given object's cached pages that have a 1302 * pindex within the given range into free pages. If the value 1303 * zero is given for "end", then the range's upper bound is 1304 * infinity. If the given object is backed by a vnode and it 1305 * transitions from having one or more cached pages to none, the 1306 * vnode's hold count is reduced. 1307 */ 1308 void 1309 vm_page_cache_free(vm_object_t object, vm_pindex_t start, vm_pindex_t end) 1310 { 1311 vm_page_t m; 1312 boolean_t empty; 1313 1314 mtx_lock(&vm_page_queue_free_mtx); 1315 if (__predict_false(vm_radix_is_empty(&object->cache))) { 1316 mtx_unlock(&vm_page_queue_free_mtx); 1317 return; 1318 } 1319 while ((m = vm_radix_lookup_ge(&object->cache, start)) != NULL) { 1320 if (end != 0 && m->pindex >= end) 1321 break; 1322 vm_radix_remove(&object->cache, m->pindex); 1323 vm_page_cache_turn_free(m); 1324 } 1325 empty = vm_radix_is_empty(&object->cache); 1326 mtx_unlock(&vm_page_queue_free_mtx); 1327 if (object->type == OBJT_VNODE && empty) 1328 vdrop(object->handle); 1329 } 1330 1331 /* 1332 * Returns the cached page that is associated with the given 1333 * object and offset. If, however, none exists, returns NULL. 1334 * 1335 * The free page queue must be locked. 1336 */ 1337 static inline vm_page_t 1338 vm_page_cache_lookup(vm_object_t object, vm_pindex_t pindex) 1339 { 1340 1341 mtx_assert(&vm_page_queue_free_mtx, MA_OWNED); 1342 return (vm_radix_lookup(&object->cache, pindex)); 1343 } 1344 1345 /* 1346 * Remove the given cached page from its containing object's 1347 * collection of cached pages. 1348 * 1349 * The free page queue must be locked. 1350 */ 1351 static void 1352 vm_page_cache_remove(vm_page_t m) 1353 { 1354 1355 mtx_assert(&vm_page_queue_free_mtx, MA_OWNED); 1356 KASSERT((m->flags & PG_CACHED) != 0, 1357 ("vm_page_cache_remove: page %p is not cached", m)); 1358 vm_radix_remove(&m->object->cache, m->pindex); 1359 m->object = NULL; 1360 vm_cnt.v_cache_count--; 1361 } 1362 1363 /* 1364 * Transfer all of the cached pages with offset greater than or 1365 * equal to 'offidxstart' from the original object's cache to the 1366 * new object's cache. However, any cached pages with offset 1367 * greater than or equal to the new object's size are kept in the 1368 * original object. Initially, the new object's cache must be 1369 * empty. Offset 'offidxstart' in the original object must 1370 * correspond to offset zero in the new object. 1371 * 1372 * The new object must be locked. 1373 */ 1374 void 1375 vm_page_cache_transfer(vm_object_t orig_object, vm_pindex_t offidxstart, 1376 vm_object_t new_object) 1377 { 1378 vm_page_t m; 1379 1380 /* 1381 * Insertion into an object's collection of cached pages 1382 * requires the object to be locked. In contrast, removal does 1383 * not. 1384 */ 1385 VM_OBJECT_ASSERT_WLOCKED(new_object); 1386 KASSERT(vm_radix_is_empty(&new_object->cache), 1387 ("vm_page_cache_transfer: object %p has cached pages", 1388 new_object)); 1389 mtx_lock(&vm_page_queue_free_mtx); 1390 while ((m = vm_radix_lookup_ge(&orig_object->cache, 1391 offidxstart)) != NULL) { 1392 /* 1393 * Transfer all of the pages with offset greater than or 1394 * equal to 'offidxstart' from the original object's 1395 * cache to the new object's cache. 1396 */ 1397 if ((m->pindex - offidxstart) >= new_object->size) 1398 break; 1399 vm_radix_remove(&orig_object->cache, m->pindex); 1400 /* Update the page's object and offset. */ 1401 m->object = new_object; 1402 m->pindex -= offidxstart; 1403 if (vm_radix_insert(&new_object->cache, m)) 1404 vm_page_cache_turn_free(m); 1405 } 1406 mtx_unlock(&vm_page_queue_free_mtx); 1407 } 1408 1409 /* 1410 * Returns TRUE if a cached page is associated with the given object and 1411 * offset, and FALSE otherwise. 1412 * 1413 * The object must be locked. 1414 */ 1415 boolean_t 1416 vm_page_is_cached(vm_object_t object, vm_pindex_t pindex) 1417 { 1418 vm_page_t m; 1419 1420 /* 1421 * Insertion into an object's collection of cached pages requires the 1422 * object to be locked. Therefore, if the object is locked and the 1423 * object's collection is empty, there is no need to acquire the free 1424 * page queues lock in order to prove that the specified page doesn't 1425 * exist. 1426 */ 1427 VM_OBJECT_ASSERT_WLOCKED(object); 1428 if (__predict_true(vm_object_cache_is_empty(object))) 1429 return (FALSE); 1430 mtx_lock(&vm_page_queue_free_mtx); 1431 m = vm_page_cache_lookup(object, pindex); 1432 mtx_unlock(&vm_page_queue_free_mtx); 1433 return (m != NULL); 1434 } 1435 1436 /* 1437 * vm_page_alloc: 1438 * 1439 * Allocate and return a page that is associated with the specified 1440 * object and offset pair. By default, this page is exclusive busied. 1441 * 1442 * The caller must always specify an allocation class. 1443 * 1444 * allocation classes: 1445 * VM_ALLOC_NORMAL normal process request 1446 * VM_ALLOC_SYSTEM system *really* needs a page 1447 * VM_ALLOC_INTERRUPT interrupt time request 1448 * 1449 * optional allocation flags: 1450 * VM_ALLOC_COUNT(number) the number of additional pages that the caller 1451 * intends to allocate 1452 * VM_ALLOC_IFCACHED return page only if it is cached 1453 * VM_ALLOC_IFNOTCACHED return NULL, do not reactivate if the page 1454 * is cached 1455 * VM_ALLOC_NOBUSY do not exclusive busy the page 1456 * VM_ALLOC_NODUMP do not include the page in a kernel core dump 1457 * VM_ALLOC_NOOBJ page is not associated with an object and 1458 * should not be exclusive busy 1459 * VM_ALLOC_SBUSY shared busy the allocated page 1460 * VM_ALLOC_WIRED wire the allocated page 1461 * VM_ALLOC_ZERO prefer a zeroed page 1462 * 1463 * This routine may not sleep. 1464 */ 1465 vm_page_t 1466 vm_page_alloc(vm_object_t object, vm_pindex_t pindex, int req) 1467 { 1468 struct vnode *vp = NULL; 1469 vm_object_t m_object; 1470 vm_page_t m, mpred; 1471 int flags, req_class; 1472 1473 mpred = 0; /* XXX: pacify gcc */ 1474 KASSERT((object != NULL) == ((req & VM_ALLOC_NOOBJ) == 0) && 1475 (object != NULL || (req & VM_ALLOC_SBUSY) == 0) && 1476 ((req & (VM_ALLOC_NOBUSY | VM_ALLOC_SBUSY)) != 1477 (VM_ALLOC_NOBUSY | VM_ALLOC_SBUSY)), 1478 ("vm_page_alloc: inconsistent object(%p)/req(%x)", (void *)object, 1479 req)); 1480 if (object != NULL) 1481 VM_OBJECT_ASSERT_WLOCKED(object); 1482 1483 req_class = req & VM_ALLOC_CLASS_MASK; 1484 1485 /* 1486 * The page daemon is allowed to dig deeper into the free page list. 1487 */ 1488 if (curproc == pageproc && req_class != VM_ALLOC_INTERRUPT) 1489 req_class = VM_ALLOC_SYSTEM; 1490 1491 if (object != NULL) { 1492 mpred = vm_radix_lookup_le(&object->rtree, pindex); 1493 KASSERT(mpred == NULL || mpred->pindex != pindex, 1494 ("vm_page_alloc: pindex already allocated")); 1495 } 1496 1497 /* 1498 * The page allocation request can came from consumers which already 1499 * hold the free page queue mutex, like vm_page_insert() in 1500 * vm_page_cache(). 1501 */ 1502 mtx_lock_flags(&vm_page_queue_free_mtx, MTX_RECURSE); 1503 if (vm_cnt.v_free_count + vm_cnt.v_cache_count > vm_cnt.v_free_reserved || 1504 (req_class == VM_ALLOC_SYSTEM && 1505 vm_cnt.v_free_count + vm_cnt.v_cache_count > vm_cnt.v_interrupt_free_min) || 1506 (req_class == VM_ALLOC_INTERRUPT && 1507 vm_cnt.v_free_count + vm_cnt.v_cache_count > 0)) { 1508 /* 1509 * Allocate from the free queue if the number of free pages 1510 * exceeds the minimum for the request class. 1511 */ 1512 if (object != NULL && 1513 (m = vm_page_cache_lookup(object, pindex)) != NULL) { 1514 if ((req & VM_ALLOC_IFNOTCACHED) != 0) { 1515 mtx_unlock(&vm_page_queue_free_mtx); 1516 return (NULL); 1517 } 1518 if (vm_phys_unfree_page(m)) 1519 vm_phys_set_pool(VM_FREEPOOL_DEFAULT, m, 0); 1520 #if VM_NRESERVLEVEL > 0 1521 else if (!vm_reserv_reactivate_page(m)) 1522 #else 1523 else 1524 #endif 1525 panic("vm_page_alloc: cache page %p is missing" 1526 " from the free queue", m); 1527 } else if ((req & VM_ALLOC_IFCACHED) != 0) { 1528 mtx_unlock(&vm_page_queue_free_mtx); 1529 return (NULL); 1530 #if VM_NRESERVLEVEL > 0 1531 } else if (object == NULL || (object->flags & (OBJ_COLORED | 1532 OBJ_FICTITIOUS)) != OBJ_COLORED || (m = 1533 vm_reserv_alloc_page(object, pindex, mpred)) == NULL) { 1534 #else 1535 } else { 1536 #endif 1537 m = vm_phys_alloc_pages(object != NULL ? 1538 VM_FREEPOOL_DEFAULT : VM_FREEPOOL_DIRECT, 0); 1539 #if VM_NRESERVLEVEL > 0 1540 if (m == NULL && vm_reserv_reclaim_inactive()) { 1541 m = vm_phys_alloc_pages(object != NULL ? 1542 VM_FREEPOOL_DEFAULT : VM_FREEPOOL_DIRECT, 1543 0); 1544 } 1545 #endif 1546 } 1547 } else { 1548 /* 1549 * Not allocatable, give up. 1550 */ 1551 mtx_unlock(&vm_page_queue_free_mtx); 1552 atomic_add_int(&vm_pageout_deficit, 1553 max((u_int)req >> VM_ALLOC_COUNT_SHIFT, 1)); 1554 pagedaemon_wakeup(); 1555 return (NULL); 1556 } 1557 1558 /* 1559 * At this point we had better have found a good page. 1560 */ 1561 KASSERT(m != NULL, ("vm_page_alloc: missing page")); 1562 KASSERT(m->queue == PQ_NONE, 1563 ("vm_page_alloc: page %p has unexpected queue %d", m, m->queue)); 1564 KASSERT(m->wire_count == 0, ("vm_page_alloc: page %p is wired", m)); 1565 KASSERT(m->hold_count == 0, ("vm_page_alloc: page %p is held", m)); 1566 KASSERT(!vm_page_sbusied(m), 1567 ("vm_page_alloc: page %p is busy", m)); 1568 KASSERT(m->dirty == 0, ("vm_page_alloc: page %p is dirty", m)); 1569 KASSERT(pmap_page_get_memattr(m) == VM_MEMATTR_DEFAULT, 1570 ("vm_page_alloc: page %p has unexpected memattr %d", m, 1571 pmap_page_get_memattr(m))); 1572 if ((m->flags & PG_CACHED) != 0) { 1573 KASSERT((m->flags & PG_ZERO) == 0, 1574 ("vm_page_alloc: cached page %p is PG_ZERO", m)); 1575 KASSERT(m->valid != 0, 1576 ("vm_page_alloc: cached page %p is invalid", m)); 1577 if (m->object == object && m->pindex == pindex) 1578 vm_cnt.v_reactivated++; 1579 else 1580 m->valid = 0; 1581 m_object = m->object; 1582 vm_page_cache_remove(m); 1583 if (m_object->type == OBJT_VNODE && 1584 vm_object_cache_is_empty(m_object)) 1585 vp = m_object->handle; 1586 } else { 1587 KASSERT(m->valid == 0, 1588 ("vm_page_alloc: free page %p is valid", m)); 1589 vm_phys_freecnt_adj(m, -1); 1590 if ((m->flags & PG_ZERO) != 0) 1591 vm_page_zero_count--; 1592 } 1593 mtx_unlock(&vm_page_queue_free_mtx); 1594 1595 /* 1596 * Initialize the page. Only the PG_ZERO flag is inherited. 1597 */ 1598 flags = 0; 1599 if ((req & VM_ALLOC_ZERO) != 0) 1600 flags = PG_ZERO; 1601 flags &= m->flags; 1602 if ((req & VM_ALLOC_NODUMP) != 0) 1603 flags |= PG_NODUMP; 1604 m->flags = flags; 1605 m->aflags = 0; 1606 m->oflags = object == NULL || (object->flags & OBJ_UNMANAGED) != 0 ? 1607 VPO_UNMANAGED : 0; 1608 m->busy_lock = VPB_UNBUSIED; 1609 if ((req & (VM_ALLOC_NOBUSY | VM_ALLOC_NOOBJ | VM_ALLOC_SBUSY)) == 0) 1610 m->busy_lock = VPB_SINGLE_EXCLUSIVER; 1611 if ((req & VM_ALLOC_SBUSY) != 0) 1612 m->busy_lock = VPB_SHARERS_WORD(1); 1613 if (req & VM_ALLOC_WIRED) { 1614 /* 1615 * The page lock is not required for wiring a page until that 1616 * page is inserted into the object. 1617 */ 1618 atomic_add_int(&vm_cnt.v_wire_count, 1); 1619 m->wire_count = 1; 1620 } 1621 m->act_count = 0; 1622 1623 if (object != NULL) { 1624 if (vm_page_insert_after(m, object, pindex, mpred)) { 1625 /* See the comment below about hold count. */ 1626 if (vp != NULL) 1627 vdrop(vp); 1628 pagedaemon_wakeup(); 1629 if (req & VM_ALLOC_WIRED) { 1630 atomic_subtract_int(&vm_cnt.v_wire_count, 1); 1631 m->wire_count = 0; 1632 } 1633 m->object = NULL; 1634 vm_page_free(m); 1635 return (NULL); 1636 } 1637 1638 /* Ignore device objects; the pager sets "memattr" for them. */ 1639 if (object->memattr != VM_MEMATTR_DEFAULT && 1640 (object->flags & OBJ_FICTITIOUS) == 0) 1641 pmap_page_set_memattr(m, object->memattr); 1642 } else 1643 m->pindex = pindex; 1644 1645 /* 1646 * The following call to vdrop() must come after the above call 1647 * to vm_page_insert() in case both affect the same object and 1648 * vnode. Otherwise, the affected vnode's hold count could 1649 * temporarily become zero. 1650 */ 1651 if (vp != NULL) 1652 vdrop(vp); 1653 1654 /* 1655 * Don't wakeup too often - wakeup the pageout daemon when 1656 * we would be nearly out of memory. 1657 */ 1658 if (vm_paging_needed()) 1659 pagedaemon_wakeup(); 1660 1661 return (m); 1662 } 1663 1664 static void 1665 vm_page_alloc_contig_vdrop(struct spglist *lst) 1666 { 1667 1668 while (!SLIST_EMPTY(lst)) { 1669 vdrop((struct vnode *)SLIST_FIRST(lst)-> plinks.s.pv); 1670 SLIST_REMOVE_HEAD(lst, plinks.s.ss); 1671 } 1672 } 1673 1674 /* 1675 * vm_page_alloc_contig: 1676 * 1677 * Allocate a contiguous set of physical pages of the given size "npages" 1678 * from the free lists. All of the physical pages must be at or above 1679 * the given physical address "low" and below the given physical address 1680 * "high". The given value "alignment" determines the alignment of the 1681 * first physical page in the set. If the given value "boundary" is 1682 * non-zero, then the set of physical pages cannot cross any physical 1683 * address boundary that is a multiple of that value. Both "alignment" 1684 * and "boundary" must be a power of two. 1685 * 1686 * If the specified memory attribute, "memattr", is VM_MEMATTR_DEFAULT, 1687 * then the memory attribute setting for the physical pages is configured 1688 * to the object's memory attribute setting. Otherwise, the memory 1689 * attribute setting for the physical pages is configured to "memattr", 1690 * overriding the object's memory attribute setting. However, if the 1691 * object's memory attribute setting is not VM_MEMATTR_DEFAULT, then the 1692 * memory attribute setting for the physical pages cannot be configured 1693 * to VM_MEMATTR_DEFAULT. 1694 * 1695 * The caller must always specify an allocation class. 1696 * 1697 * allocation classes: 1698 * VM_ALLOC_NORMAL normal process request 1699 * VM_ALLOC_SYSTEM system *really* needs a page 1700 * VM_ALLOC_INTERRUPT interrupt time request 1701 * 1702 * optional allocation flags: 1703 * VM_ALLOC_NOBUSY do not exclusive busy the page 1704 * VM_ALLOC_NOOBJ page is not associated with an object and 1705 * should not be exclusive busy 1706 * VM_ALLOC_SBUSY shared busy the allocated page 1707 * VM_ALLOC_WIRED wire the allocated page 1708 * VM_ALLOC_ZERO prefer a zeroed page 1709 * 1710 * This routine may not sleep. 1711 */ 1712 vm_page_t 1713 vm_page_alloc_contig(vm_object_t object, vm_pindex_t pindex, int req, 1714 u_long npages, vm_paddr_t low, vm_paddr_t high, u_long alignment, 1715 vm_paddr_t boundary, vm_memattr_t memattr) 1716 { 1717 struct vnode *drop; 1718 struct spglist deferred_vdrop_list; 1719 vm_page_t m, m_tmp, m_ret; 1720 u_int flags; 1721 int req_class; 1722 1723 KASSERT((object != NULL) == ((req & VM_ALLOC_NOOBJ) == 0) && 1724 (object != NULL || (req & VM_ALLOC_SBUSY) == 0) && 1725 ((req & (VM_ALLOC_NOBUSY | VM_ALLOC_SBUSY)) != 1726 (VM_ALLOC_NOBUSY | VM_ALLOC_SBUSY)), 1727 ("vm_page_alloc: inconsistent object(%p)/req(%x)", (void *)object, 1728 req)); 1729 if (object != NULL) { 1730 VM_OBJECT_ASSERT_WLOCKED(object); 1731 KASSERT(object->type == OBJT_PHYS, 1732 ("vm_page_alloc_contig: object %p isn't OBJT_PHYS", 1733 object)); 1734 } 1735 KASSERT(npages > 0, ("vm_page_alloc_contig: npages is zero")); 1736 req_class = req & VM_ALLOC_CLASS_MASK; 1737 1738 /* 1739 * The page daemon is allowed to dig deeper into the free page list. 1740 */ 1741 if (curproc == pageproc && req_class != VM_ALLOC_INTERRUPT) 1742 req_class = VM_ALLOC_SYSTEM; 1743 1744 SLIST_INIT(&deferred_vdrop_list); 1745 mtx_lock(&vm_page_queue_free_mtx); 1746 if (vm_cnt.v_free_count + vm_cnt.v_cache_count >= npages + 1747 vm_cnt.v_free_reserved || (req_class == VM_ALLOC_SYSTEM && 1748 vm_cnt.v_free_count + vm_cnt.v_cache_count >= npages + 1749 vm_cnt.v_interrupt_free_min) || (req_class == VM_ALLOC_INTERRUPT && 1750 vm_cnt.v_free_count + vm_cnt.v_cache_count >= npages)) { 1751 #if VM_NRESERVLEVEL > 0 1752 retry: 1753 if (object == NULL || (object->flags & OBJ_COLORED) == 0 || 1754 (m_ret = vm_reserv_alloc_contig(object, pindex, npages, 1755 low, high, alignment, boundary)) == NULL) 1756 #endif 1757 m_ret = vm_phys_alloc_contig(npages, low, high, 1758 alignment, boundary); 1759 } else { 1760 mtx_unlock(&vm_page_queue_free_mtx); 1761 atomic_add_int(&vm_pageout_deficit, npages); 1762 pagedaemon_wakeup(); 1763 return (NULL); 1764 } 1765 if (m_ret != NULL) 1766 for (m = m_ret; m < &m_ret[npages]; m++) { 1767 drop = vm_page_alloc_init(m); 1768 if (drop != NULL) { 1769 /* 1770 * Enqueue the vnode for deferred vdrop(). 1771 */ 1772 m->plinks.s.pv = drop; 1773 SLIST_INSERT_HEAD(&deferred_vdrop_list, m, 1774 plinks.s.ss); 1775 } 1776 } 1777 else { 1778 #if VM_NRESERVLEVEL > 0 1779 if (vm_reserv_reclaim_contig(npages, low, high, alignment, 1780 boundary)) 1781 goto retry; 1782 #endif 1783 } 1784 mtx_unlock(&vm_page_queue_free_mtx); 1785 if (m_ret == NULL) 1786 return (NULL); 1787 1788 /* 1789 * Initialize the pages. Only the PG_ZERO flag is inherited. 1790 */ 1791 flags = 0; 1792 if ((req & VM_ALLOC_ZERO) != 0) 1793 flags = PG_ZERO; 1794 if ((req & VM_ALLOC_NODUMP) != 0) 1795 flags |= PG_NODUMP; 1796 if ((req & VM_ALLOC_WIRED) != 0) 1797 atomic_add_int(&vm_cnt.v_wire_count, npages); 1798 if (object != NULL) { 1799 if (object->memattr != VM_MEMATTR_DEFAULT && 1800 memattr == VM_MEMATTR_DEFAULT) 1801 memattr = object->memattr; 1802 } 1803 for (m = m_ret; m < &m_ret[npages]; m++) { 1804 m->aflags = 0; 1805 m->flags = (m->flags | PG_NODUMP) & flags; 1806 m->busy_lock = VPB_UNBUSIED; 1807 if (object != NULL) { 1808 if ((req & (VM_ALLOC_NOBUSY | VM_ALLOC_SBUSY)) == 0) 1809 m->busy_lock = VPB_SINGLE_EXCLUSIVER; 1810 if ((req & VM_ALLOC_SBUSY) != 0) 1811 m->busy_lock = VPB_SHARERS_WORD(1); 1812 } 1813 if ((req & VM_ALLOC_WIRED) != 0) 1814 m->wire_count = 1; 1815 /* Unmanaged pages don't use "act_count". */ 1816 m->oflags = VPO_UNMANAGED; 1817 if (object != NULL) { 1818 if (vm_page_insert(m, object, pindex)) { 1819 vm_page_alloc_contig_vdrop( 1820 &deferred_vdrop_list); 1821 if (vm_paging_needed()) 1822 pagedaemon_wakeup(); 1823 if ((req & VM_ALLOC_WIRED) != 0) 1824 atomic_subtract_int(&vm_cnt.v_wire_count, 1825 npages); 1826 for (m_tmp = m, m = m_ret; 1827 m < &m_ret[npages]; m++) { 1828 if ((req & VM_ALLOC_WIRED) != 0) 1829 m->wire_count = 0; 1830 if (m >= m_tmp) 1831 m->object = NULL; 1832 vm_page_free(m); 1833 } 1834 return (NULL); 1835 } 1836 } else 1837 m->pindex = pindex; 1838 if (memattr != VM_MEMATTR_DEFAULT) 1839 pmap_page_set_memattr(m, memattr); 1840 pindex++; 1841 } 1842 vm_page_alloc_contig_vdrop(&deferred_vdrop_list); 1843 if (vm_paging_needed()) 1844 pagedaemon_wakeup(); 1845 return (m_ret); 1846 } 1847 1848 /* 1849 * Initialize a page that has been freshly dequeued from a freelist. 1850 * The caller has to drop the vnode returned, if it is not NULL. 1851 * 1852 * This function may only be used to initialize unmanaged pages. 1853 * 1854 * To be called with vm_page_queue_free_mtx held. 1855 */ 1856 static struct vnode * 1857 vm_page_alloc_init(vm_page_t m) 1858 { 1859 struct vnode *drop; 1860 vm_object_t m_object; 1861 1862 KASSERT(m->queue == PQ_NONE, 1863 ("vm_page_alloc_init: page %p has unexpected queue %d", 1864 m, m->queue)); 1865 KASSERT(m->wire_count == 0, 1866 ("vm_page_alloc_init: page %p is wired", m)); 1867 KASSERT(m->hold_count == 0, 1868 ("vm_page_alloc_init: page %p is held", m)); 1869 KASSERT(!vm_page_sbusied(m), 1870 ("vm_page_alloc_init: page %p is busy", m)); 1871 KASSERT(m->dirty == 0, 1872 ("vm_page_alloc_init: page %p is dirty", m)); 1873 KASSERT(pmap_page_get_memattr(m) == VM_MEMATTR_DEFAULT, 1874 ("vm_page_alloc_init: page %p has unexpected memattr %d", 1875 m, pmap_page_get_memattr(m))); 1876 mtx_assert(&vm_page_queue_free_mtx, MA_OWNED); 1877 drop = NULL; 1878 if ((m->flags & PG_CACHED) != 0) { 1879 KASSERT((m->flags & PG_ZERO) == 0, 1880 ("vm_page_alloc_init: cached page %p is PG_ZERO", m)); 1881 m->valid = 0; 1882 m_object = m->object; 1883 vm_page_cache_remove(m); 1884 if (m_object->type == OBJT_VNODE && 1885 vm_object_cache_is_empty(m_object)) 1886 drop = m_object->handle; 1887 } else { 1888 KASSERT(m->valid == 0, 1889 ("vm_page_alloc_init: free page %p is valid", m)); 1890 vm_phys_freecnt_adj(m, -1); 1891 if ((m->flags & PG_ZERO) != 0) 1892 vm_page_zero_count--; 1893 } 1894 return (drop); 1895 } 1896 1897 /* 1898 * vm_page_alloc_freelist: 1899 * 1900 * Allocate a physical page from the specified free page list. 1901 * 1902 * The caller must always specify an allocation class. 1903 * 1904 * allocation classes: 1905 * VM_ALLOC_NORMAL normal process request 1906 * VM_ALLOC_SYSTEM system *really* needs a page 1907 * VM_ALLOC_INTERRUPT interrupt time request 1908 * 1909 * optional allocation flags: 1910 * VM_ALLOC_COUNT(number) the number of additional pages that the caller 1911 * intends to allocate 1912 * VM_ALLOC_WIRED wire the allocated page 1913 * VM_ALLOC_ZERO prefer a zeroed page 1914 * 1915 * This routine may not sleep. 1916 */ 1917 vm_page_t 1918 vm_page_alloc_freelist(int flind, int req) 1919 { 1920 struct vnode *drop; 1921 vm_page_t m; 1922 u_int flags; 1923 int req_class; 1924 1925 req_class = req & VM_ALLOC_CLASS_MASK; 1926 1927 /* 1928 * The page daemon is allowed to dig deeper into the free page list. 1929 */ 1930 if (curproc == pageproc && req_class != VM_ALLOC_INTERRUPT) 1931 req_class = VM_ALLOC_SYSTEM; 1932 1933 /* 1934 * Do not allocate reserved pages unless the req has asked for it. 1935 */ 1936 mtx_lock_flags(&vm_page_queue_free_mtx, MTX_RECURSE); 1937 if (vm_cnt.v_free_count + vm_cnt.v_cache_count > vm_cnt.v_free_reserved || 1938 (req_class == VM_ALLOC_SYSTEM && 1939 vm_cnt.v_free_count + vm_cnt.v_cache_count > vm_cnt.v_interrupt_free_min) || 1940 (req_class == VM_ALLOC_INTERRUPT && 1941 vm_cnt.v_free_count + vm_cnt.v_cache_count > 0)) 1942 m = vm_phys_alloc_freelist_pages(flind, VM_FREEPOOL_DIRECT, 0); 1943 else { 1944 mtx_unlock(&vm_page_queue_free_mtx); 1945 atomic_add_int(&vm_pageout_deficit, 1946 max((u_int)req >> VM_ALLOC_COUNT_SHIFT, 1)); 1947 pagedaemon_wakeup(); 1948 return (NULL); 1949 } 1950 if (m == NULL) { 1951 mtx_unlock(&vm_page_queue_free_mtx); 1952 return (NULL); 1953 } 1954 drop = vm_page_alloc_init(m); 1955 mtx_unlock(&vm_page_queue_free_mtx); 1956 1957 /* 1958 * Initialize the page. Only the PG_ZERO flag is inherited. 1959 */ 1960 m->aflags = 0; 1961 flags = 0; 1962 if ((req & VM_ALLOC_ZERO) != 0) 1963 flags = PG_ZERO; 1964 m->flags &= flags; 1965 if ((req & VM_ALLOC_WIRED) != 0) { 1966 /* 1967 * The page lock is not required for wiring a page that does 1968 * not belong to an object. 1969 */ 1970 atomic_add_int(&vm_cnt.v_wire_count, 1); 1971 m->wire_count = 1; 1972 } 1973 /* Unmanaged pages don't use "act_count". */ 1974 m->oflags = VPO_UNMANAGED; 1975 if (drop != NULL) 1976 vdrop(drop); 1977 if (vm_paging_needed()) 1978 pagedaemon_wakeup(); 1979 return (m); 1980 } 1981 1982 /* 1983 * vm_wait: (also see VM_WAIT macro) 1984 * 1985 * Sleep until free pages are available for allocation. 1986 * - Called in various places before memory allocations. 1987 */ 1988 void 1989 vm_wait(void) 1990 { 1991 1992 mtx_lock(&vm_page_queue_free_mtx); 1993 if (curproc == pageproc) { 1994 vm_pageout_pages_needed = 1; 1995 msleep(&vm_pageout_pages_needed, &vm_page_queue_free_mtx, 1996 PDROP | PSWP, "VMWait", 0); 1997 } else { 1998 if (!vm_pages_needed) { 1999 vm_pages_needed = 1; 2000 wakeup(&vm_pages_needed); 2001 } 2002 msleep(&vm_cnt.v_free_count, &vm_page_queue_free_mtx, PDROP | PVM, 2003 "vmwait", 0); 2004 } 2005 } 2006 2007 /* 2008 * vm_waitpfault: (also see VM_WAITPFAULT macro) 2009 * 2010 * Sleep until free pages are available for allocation. 2011 * - Called only in vm_fault so that processes page faulting 2012 * can be easily tracked. 2013 * - Sleeps at a lower priority than vm_wait() so that vm_wait()ing 2014 * processes will be able to grab memory first. Do not change 2015 * this balance without careful testing first. 2016 */ 2017 void 2018 vm_waitpfault(void) 2019 { 2020 2021 mtx_lock(&vm_page_queue_free_mtx); 2022 if (!vm_pages_needed) { 2023 vm_pages_needed = 1; 2024 wakeup(&vm_pages_needed); 2025 } 2026 msleep(&vm_cnt.v_free_count, &vm_page_queue_free_mtx, PDROP | PUSER, 2027 "pfault", 0); 2028 } 2029 2030 struct vm_pagequeue * 2031 vm_page_pagequeue(vm_page_t m) 2032 { 2033 2034 return (&vm_phys_domain(m)->vmd_pagequeues[m->queue]); 2035 } 2036 2037 /* 2038 * vm_page_dequeue: 2039 * 2040 * Remove the given page from its current page queue. 2041 * 2042 * The page must be locked. 2043 */ 2044 void 2045 vm_page_dequeue(vm_page_t m) 2046 { 2047 struct vm_pagequeue *pq; 2048 2049 vm_page_assert_locked(m); 2050 KASSERT(m->queue < PQ_COUNT, ("vm_page_dequeue: page %p is not queued", 2051 m)); 2052 pq = vm_page_pagequeue(m); 2053 vm_pagequeue_lock(pq); 2054 m->queue = PQ_NONE; 2055 TAILQ_REMOVE(&pq->pq_pl, m, plinks.q); 2056 vm_pagequeue_cnt_dec(pq); 2057 vm_pagequeue_unlock(pq); 2058 } 2059 2060 /* 2061 * vm_page_dequeue_locked: 2062 * 2063 * Remove the given page from its current page queue. 2064 * 2065 * The page and page queue must be locked. 2066 */ 2067 void 2068 vm_page_dequeue_locked(vm_page_t m) 2069 { 2070 struct vm_pagequeue *pq; 2071 2072 vm_page_lock_assert(m, MA_OWNED); 2073 pq = vm_page_pagequeue(m); 2074 vm_pagequeue_assert_locked(pq); 2075 m->queue = PQ_NONE; 2076 TAILQ_REMOVE(&pq->pq_pl, m, plinks.q); 2077 vm_pagequeue_cnt_dec(pq); 2078 } 2079 2080 /* 2081 * vm_page_enqueue: 2082 * 2083 * Add the given page to the specified page queue. 2084 * 2085 * The page must be locked. 2086 */ 2087 static void 2088 vm_page_enqueue(uint8_t queue, vm_page_t m) 2089 { 2090 struct vm_pagequeue *pq; 2091 2092 vm_page_lock_assert(m, MA_OWNED); 2093 KASSERT(queue < PQ_COUNT, 2094 ("vm_page_enqueue: invalid queue %u request for page %p", 2095 queue, m)); 2096 pq = &vm_phys_domain(m)->vmd_pagequeues[queue]; 2097 vm_pagequeue_lock(pq); 2098 m->queue = queue; 2099 TAILQ_INSERT_TAIL(&pq->pq_pl, m, plinks.q); 2100 vm_pagequeue_cnt_inc(pq); 2101 vm_pagequeue_unlock(pq); 2102 } 2103 2104 /* 2105 * vm_page_requeue: 2106 * 2107 * Move the given page to the tail of its current page queue. 2108 * 2109 * The page must be locked. 2110 */ 2111 void 2112 vm_page_requeue(vm_page_t m) 2113 { 2114 struct vm_pagequeue *pq; 2115 2116 vm_page_lock_assert(m, MA_OWNED); 2117 KASSERT(m->queue != PQ_NONE, 2118 ("vm_page_requeue: page %p is not queued", m)); 2119 pq = vm_page_pagequeue(m); 2120 vm_pagequeue_lock(pq); 2121 TAILQ_REMOVE(&pq->pq_pl, m, plinks.q); 2122 TAILQ_INSERT_TAIL(&pq->pq_pl, m, plinks.q); 2123 vm_pagequeue_unlock(pq); 2124 } 2125 2126 /* 2127 * vm_page_requeue_locked: 2128 * 2129 * Move the given page to the tail of its current page queue. 2130 * 2131 * The page queue must be locked. 2132 */ 2133 void 2134 vm_page_requeue_locked(vm_page_t m) 2135 { 2136 struct vm_pagequeue *pq; 2137 2138 KASSERT(m->queue != PQ_NONE, 2139 ("vm_page_requeue_locked: page %p is not queued", m)); 2140 pq = vm_page_pagequeue(m); 2141 vm_pagequeue_assert_locked(pq); 2142 TAILQ_REMOVE(&pq->pq_pl, m, plinks.q); 2143 TAILQ_INSERT_TAIL(&pq->pq_pl, m, plinks.q); 2144 } 2145 2146 /* 2147 * vm_page_activate: 2148 * 2149 * Put the specified page on the active list (if appropriate). 2150 * Ensure that act_count is at least ACT_INIT but do not otherwise 2151 * mess with it. 2152 * 2153 * The page must be locked. 2154 */ 2155 void 2156 vm_page_activate(vm_page_t m) 2157 { 2158 int queue; 2159 2160 vm_page_lock_assert(m, MA_OWNED); 2161 if ((queue = m->queue) != PQ_ACTIVE) { 2162 if (m->wire_count == 0 && (m->oflags & VPO_UNMANAGED) == 0) { 2163 if (m->act_count < ACT_INIT) 2164 m->act_count = ACT_INIT; 2165 if (queue != PQ_NONE) 2166 vm_page_dequeue(m); 2167 vm_page_enqueue(PQ_ACTIVE, m); 2168 } else 2169 KASSERT(queue == PQ_NONE, 2170 ("vm_page_activate: wired page %p is queued", m)); 2171 } else { 2172 if (m->act_count < ACT_INIT) 2173 m->act_count = ACT_INIT; 2174 } 2175 } 2176 2177 /* 2178 * vm_page_free_wakeup: 2179 * 2180 * Helper routine for vm_page_free_toq() and vm_page_cache(). This 2181 * routine is called when a page has been added to the cache or free 2182 * queues. 2183 * 2184 * The page queues must be locked. 2185 */ 2186 static inline void 2187 vm_page_free_wakeup(void) 2188 { 2189 2190 mtx_assert(&vm_page_queue_free_mtx, MA_OWNED); 2191 /* 2192 * if pageout daemon needs pages, then tell it that there are 2193 * some free. 2194 */ 2195 if (vm_pageout_pages_needed && 2196 vm_cnt.v_cache_count + vm_cnt.v_free_count >= vm_cnt.v_pageout_free_min) { 2197 wakeup(&vm_pageout_pages_needed); 2198 vm_pageout_pages_needed = 0; 2199 } 2200 /* 2201 * wakeup processes that are waiting on memory if we hit a 2202 * high water mark. And wakeup scheduler process if we have 2203 * lots of memory. this process will swapin processes. 2204 */ 2205 if (vm_pages_needed && !vm_page_count_min()) { 2206 vm_pages_needed = 0; 2207 wakeup(&vm_cnt.v_free_count); 2208 } 2209 } 2210 2211 /* 2212 * Turn a cached page into a free page, by changing its attributes. 2213 * Keep the statistics up-to-date. 2214 * 2215 * The free page queue must be locked. 2216 */ 2217 static void 2218 vm_page_cache_turn_free(vm_page_t m) 2219 { 2220 2221 mtx_assert(&vm_page_queue_free_mtx, MA_OWNED); 2222 2223 m->object = NULL; 2224 m->valid = 0; 2225 KASSERT((m->flags & PG_CACHED) != 0, 2226 ("vm_page_cache_turn_free: page %p is not cached", m)); 2227 m->flags &= ~PG_CACHED; 2228 vm_cnt.v_cache_count--; 2229 vm_phys_freecnt_adj(m, 1); 2230 } 2231 2232 /* 2233 * vm_page_free_toq: 2234 * 2235 * Returns the given page to the free list, 2236 * disassociating it with any VM object. 2237 * 2238 * The object must be locked. The page must be locked if it is managed. 2239 */ 2240 void 2241 vm_page_free_toq(vm_page_t m) 2242 { 2243 2244 if ((m->oflags & VPO_UNMANAGED) == 0) { 2245 vm_page_lock_assert(m, MA_OWNED); 2246 KASSERT(!pmap_page_is_mapped(m), 2247 ("vm_page_free_toq: freeing mapped page %p", m)); 2248 } else 2249 KASSERT(m->queue == PQ_NONE, 2250 ("vm_page_free_toq: unmanaged page %p is queued", m)); 2251 PCPU_INC(cnt.v_tfree); 2252 2253 if (vm_page_sbusied(m)) 2254 panic("vm_page_free: freeing busy page %p", m); 2255 2256 /* 2257 * Unqueue, then remove page. Note that we cannot destroy 2258 * the page here because we do not want to call the pager's 2259 * callback routine until after we've put the page on the 2260 * appropriate free queue. 2261 */ 2262 vm_page_remque(m); 2263 vm_page_remove(m); 2264 2265 /* 2266 * If fictitious remove object association and 2267 * return, otherwise delay object association removal. 2268 */ 2269 if ((m->flags & PG_FICTITIOUS) != 0) { 2270 return; 2271 } 2272 2273 m->valid = 0; 2274 vm_page_undirty(m); 2275 2276 if (m->wire_count != 0) 2277 panic("vm_page_free: freeing wired page %p", m); 2278 if (m->hold_count != 0) { 2279 m->flags &= ~PG_ZERO; 2280 KASSERT((m->flags & PG_UNHOLDFREE) == 0, 2281 ("vm_page_free: freeing PG_UNHOLDFREE page %p", m)); 2282 m->flags |= PG_UNHOLDFREE; 2283 } else { 2284 /* 2285 * Restore the default memory attribute to the page. 2286 */ 2287 if (pmap_page_get_memattr(m) != VM_MEMATTR_DEFAULT) 2288 pmap_page_set_memattr(m, VM_MEMATTR_DEFAULT); 2289 2290 /* 2291 * Insert the page into the physical memory allocator's 2292 * cache/free page queues. 2293 */ 2294 mtx_lock(&vm_page_queue_free_mtx); 2295 vm_phys_freecnt_adj(m, 1); 2296 #if VM_NRESERVLEVEL > 0 2297 if (!vm_reserv_free_page(m)) 2298 #else 2299 if (TRUE) 2300 #endif 2301 vm_phys_free_pages(m, 0); 2302 if ((m->flags & PG_ZERO) != 0) 2303 ++vm_page_zero_count; 2304 else 2305 vm_page_zero_idle_wakeup(); 2306 vm_page_free_wakeup(); 2307 mtx_unlock(&vm_page_queue_free_mtx); 2308 } 2309 } 2310 2311 /* 2312 * vm_page_wire: 2313 * 2314 * Mark this page as wired down by yet 2315 * another map, removing it from paging queues 2316 * as necessary. 2317 * 2318 * If the page is fictitious, then its wire count must remain one. 2319 * 2320 * The page must be locked. 2321 */ 2322 void 2323 vm_page_wire(vm_page_t m) 2324 { 2325 2326 /* 2327 * Only bump the wire statistics if the page is not already wired, 2328 * and only unqueue the page if it is on some queue (if it is unmanaged 2329 * it is already off the queues). 2330 */ 2331 vm_page_lock_assert(m, MA_OWNED); 2332 if ((m->flags & PG_FICTITIOUS) != 0) { 2333 KASSERT(m->wire_count == 1, 2334 ("vm_page_wire: fictitious page %p's wire count isn't one", 2335 m)); 2336 return; 2337 } 2338 if (m->wire_count == 0) { 2339 KASSERT((m->oflags & VPO_UNMANAGED) == 0 || 2340 m->queue == PQ_NONE, 2341 ("vm_page_wire: unmanaged page %p is queued", m)); 2342 vm_page_remque(m); 2343 atomic_add_int(&vm_cnt.v_wire_count, 1); 2344 } 2345 m->wire_count++; 2346 KASSERT(m->wire_count != 0, ("vm_page_wire: wire_count overflow m=%p", m)); 2347 } 2348 2349 /* 2350 * vm_page_unwire: 2351 * 2352 * Release one wiring of the specified page, potentially enabling it to be 2353 * paged again. If paging is enabled, then the value of the parameter 2354 * "queue" determines the queue to which the page is added. 2355 * 2356 * However, unless the page belongs to an object, it is not enqueued because 2357 * it cannot be paged out. 2358 * 2359 * If a page is fictitious, then its wire count must always be one. 2360 * 2361 * A managed page must be locked. 2362 */ 2363 void 2364 vm_page_unwire(vm_page_t m, uint8_t queue) 2365 { 2366 2367 KASSERT(queue < PQ_COUNT, 2368 ("vm_page_unwire: invalid queue %u request for page %p", 2369 queue, m)); 2370 if ((m->oflags & VPO_UNMANAGED) == 0) 2371 vm_page_lock_assert(m, MA_OWNED); 2372 if ((m->flags & PG_FICTITIOUS) != 0) { 2373 KASSERT(m->wire_count == 1, 2374 ("vm_page_unwire: fictitious page %p's wire count isn't one", m)); 2375 return; 2376 } 2377 if (m->wire_count > 0) { 2378 m->wire_count--; 2379 if (m->wire_count == 0) { 2380 atomic_subtract_int(&vm_cnt.v_wire_count, 1); 2381 if ((m->oflags & VPO_UNMANAGED) != 0 || 2382 m->object == NULL) 2383 return; 2384 if (queue == PQ_INACTIVE) 2385 m->flags &= ~PG_WINATCFLS; 2386 vm_page_enqueue(queue, m); 2387 } 2388 } else 2389 panic("vm_page_unwire: page %p's wire count is zero", m); 2390 } 2391 2392 /* 2393 * Move the specified page to the inactive queue. 2394 * 2395 * Many pages placed on the inactive queue should actually go 2396 * into the cache, but it is difficult to figure out which. What 2397 * we do instead, if the inactive target is well met, is to put 2398 * clean pages at the head of the inactive queue instead of the tail. 2399 * This will cause them to be moved to the cache more quickly and 2400 * if not actively re-referenced, reclaimed more quickly. If we just 2401 * stick these pages at the end of the inactive queue, heavy filesystem 2402 * meta-data accesses can cause an unnecessary paging load on memory bound 2403 * processes. This optimization causes one-time-use metadata to be 2404 * reused more quickly. 2405 * 2406 * Normally athead is 0 resulting in LRU operation. athead is set 2407 * to 1 if we want this page to be 'as if it were placed in the cache', 2408 * except without unmapping it from the process address space. 2409 * 2410 * The page must be locked. 2411 */ 2412 static inline void 2413 _vm_page_deactivate(vm_page_t m, int athead) 2414 { 2415 struct vm_pagequeue *pq; 2416 int queue; 2417 2418 vm_page_lock_assert(m, MA_OWNED); 2419 2420 /* 2421 * Ignore if already inactive. 2422 */ 2423 if ((queue = m->queue) == PQ_INACTIVE) 2424 return; 2425 if (m->wire_count == 0 && (m->oflags & VPO_UNMANAGED) == 0) { 2426 if (queue != PQ_NONE) 2427 vm_page_dequeue(m); 2428 m->flags &= ~PG_WINATCFLS; 2429 pq = &vm_phys_domain(m)->vmd_pagequeues[PQ_INACTIVE]; 2430 vm_pagequeue_lock(pq); 2431 m->queue = PQ_INACTIVE; 2432 if (athead) 2433 TAILQ_INSERT_HEAD(&pq->pq_pl, m, plinks.q); 2434 else 2435 TAILQ_INSERT_TAIL(&pq->pq_pl, m, plinks.q); 2436 vm_pagequeue_cnt_inc(pq); 2437 vm_pagequeue_unlock(pq); 2438 } 2439 } 2440 2441 /* 2442 * Move the specified page to the inactive queue. 2443 * 2444 * The page must be locked. 2445 */ 2446 void 2447 vm_page_deactivate(vm_page_t m) 2448 { 2449 2450 _vm_page_deactivate(m, 0); 2451 } 2452 2453 /* 2454 * vm_page_try_to_cache: 2455 * 2456 * Returns 0 on failure, 1 on success 2457 */ 2458 int 2459 vm_page_try_to_cache(vm_page_t m) 2460 { 2461 2462 vm_page_lock_assert(m, MA_OWNED); 2463 VM_OBJECT_ASSERT_WLOCKED(m->object); 2464 if (m->dirty || m->hold_count || m->wire_count || 2465 (m->oflags & VPO_UNMANAGED) != 0 || vm_page_busied(m)) 2466 return (0); 2467 pmap_remove_all(m); 2468 if (m->dirty) 2469 return (0); 2470 vm_page_cache(m); 2471 return (1); 2472 } 2473 2474 /* 2475 * vm_page_try_to_free() 2476 * 2477 * Attempt to free the page. If we cannot free it, we do nothing. 2478 * 1 is returned on success, 0 on failure. 2479 */ 2480 int 2481 vm_page_try_to_free(vm_page_t m) 2482 { 2483 2484 vm_page_lock_assert(m, MA_OWNED); 2485 if (m->object != NULL) 2486 VM_OBJECT_ASSERT_WLOCKED(m->object); 2487 if (m->dirty || m->hold_count || m->wire_count || 2488 (m->oflags & VPO_UNMANAGED) != 0 || vm_page_busied(m)) 2489 return (0); 2490 pmap_remove_all(m); 2491 if (m->dirty) 2492 return (0); 2493 vm_page_free(m); 2494 return (1); 2495 } 2496 2497 /* 2498 * vm_page_cache 2499 * 2500 * Put the specified page onto the page cache queue (if appropriate). 2501 * 2502 * The object and page must be locked. 2503 */ 2504 void 2505 vm_page_cache(vm_page_t m) 2506 { 2507 vm_object_t object; 2508 boolean_t cache_was_empty; 2509 2510 vm_page_lock_assert(m, MA_OWNED); 2511 object = m->object; 2512 VM_OBJECT_ASSERT_WLOCKED(object); 2513 if (vm_page_busied(m) || (m->oflags & VPO_UNMANAGED) || 2514 m->hold_count || m->wire_count) 2515 panic("vm_page_cache: attempting to cache busy page"); 2516 KASSERT(!pmap_page_is_mapped(m), 2517 ("vm_page_cache: page %p is mapped", m)); 2518 KASSERT(m->dirty == 0, ("vm_page_cache: page %p is dirty", m)); 2519 if (m->valid == 0 || object->type == OBJT_DEFAULT || 2520 (object->type == OBJT_SWAP && 2521 !vm_pager_has_page(object, m->pindex, NULL, NULL))) { 2522 /* 2523 * Hypothesis: A cache-eligible page belonging to a 2524 * default object or swap object but without a backing 2525 * store must be zero filled. 2526 */ 2527 vm_page_free(m); 2528 return; 2529 } 2530 KASSERT((m->flags & PG_CACHED) == 0, 2531 ("vm_page_cache: page %p is already cached", m)); 2532 2533 /* 2534 * Remove the page from the paging queues. 2535 */ 2536 vm_page_remque(m); 2537 2538 /* 2539 * Remove the page from the object's collection of resident 2540 * pages. 2541 */ 2542 vm_radix_remove(&object->rtree, m->pindex); 2543 TAILQ_REMOVE(&object->memq, m, listq); 2544 object->resident_page_count--; 2545 2546 /* 2547 * Restore the default memory attribute to the page. 2548 */ 2549 if (pmap_page_get_memattr(m) != VM_MEMATTR_DEFAULT) 2550 pmap_page_set_memattr(m, VM_MEMATTR_DEFAULT); 2551 2552 /* 2553 * Insert the page into the object's collection of cached pages 2554 * and the physical memory allocator's cache/free page queues. 2555 */ 2556 m->flags &= ~PG_ZERO; 2557 mtx_lock(&vm_page_queue_free_mtx); 2558 cache_was_empty = vm_radix_is_empty(&object->cache); 2559 if (vm_radix_insert(&object->cache, m)) { 2560 mtx_unlock(&vm_page_queue_free_mtx); 2561 if (object->resident_page_count == 0) 2562 vdrop(object->handle); 2563 m->object = NULL; 2564 vm_page_free(m); 2565 return; 2566 } 2567 2568 /* 2569 * The above call to vm_radix_insert() could reclaim the one pre- 2570 * existing cached page from this object, resulting in a call to 2571 * vdrop(). 2572 */ 2573 if (!cache_was_empty) 2574 cache_was_empty = vm_radix_is_singleton(&object->cache); 2575 2576 m->flags |= PG_CACHED; 2577 vm_cnt.v_cache_count++; 2578 PCPU_INC(cnt.v_tcached); 2579 #if VM_NRESERVLEVEL > 0 2580 if (!vm_reserv_free_page(m)) { 2581 #else 2582 if (TRUE) { 2583 #endif 2584 vm_phys_set_pool(VM_FREEPOOL_CACHE, m, 0); 2585 vm_phys_free_pages(m, 0); 2586 } 2587 vm_page_free_wakeup(); 2588 mtx_unlock(&vm_page_queue_free_mtx); 2589 2590 /* 2591 * Increment the vnode's hold count if this is the object's only 2592 * cached page. Decrement the vnode's hold count if this was 2593 * the object's only resident page. 2594 */ 2595 if (object->type == OBJT_VNODE) { 2596 if (cache_was_empty && object->resident_page_count != 0) 2597 vhold(object->handle); 2598 else if (!cache_was_empty && object->resident_page_count == 0) 2599 vdrop(object->handle); 2600 } 2601 } 2602 2603 /* 2604 * vm_page_advise 2605 * 2606 * Cache, deactivate, or do nothing as appropriate. This routine 2607 * is used by madvise(). 2608 * 2609 * Generally speaking we want to move the page into the cache so 2610 * it gets reused quickly. However, this can result in a silly syndrome 2611 * due to the page recycling too quickly. Small objects will not be 2612 * fully cached. On the other hand, if we move the page to the inactive 2613 * queue we wind up with a problem whereby very large objects 2614 * unnecessarily blow away our inactive and cache queues. 2615 * 2616 * The solution is to move the pages based on a fixed weighting. We 2617 * either leave them alone, deactivate them, or move them to the cache, 2618 * where moving them to the cache has the highest weighting. 2619 * By forcing some pages into other queues we eventually force the 2620 * system to balance the queues, potentially recovering other unrelated 2621 * space from active. The idea is to not force this to happen too 2622 * often. 2623 * 2624 * The object and page must be locked. 2625 */ 2626 void 2627 vm_page_advise(vm_page_t m, int advice) 2628 { 2629 int dnw, head; 2630 2631 vm_page_assert_locked(m); 2632 VM_OBJECT_ASSERT_WLOCKED(m->object); 2633 if (advice == MADV_FREE) { 2634 /* 2635 * Mark the page clean. This will allow the page to be freed 2636 * up by the system. However, such pages are often reused 2637 * quickly by malloc() so we do not do anything that would 2638 * cause a page fault if we can help it. 2639 * 2640 * Specifically, we do not try to actually free the page now 2641 * nor do we try to put it in the cache (which would cause a 2642 * page fault on reuse). 2643 * 2644 * But we do make the page is freeable as we can without 2645 * actually taking the step of unmapping it. 2646 */ 2647 m->dirty = 0; 2648 m->act_count = 0; 2649 } else if (advice != MADV_DONTNEED) 2650 return; 2651 dnw = PCPU_GET(dnweight); 2652 PCPU_INC(dnweight); 2653 2654 /* 2655 * Occasionally leave the page alone. 2656 */ 2657 if ((dnw & 0x01F0) == 0 || m->queue == PQ_INACTIVE) { 2658 if (m->act_count >= ACT_INIT) 2659 --m->act_count; 2660 return; 2661 } 2662 2663 /* 2664 * Clear any references to the page. Otherwise, the page daemon will 2665 * immediately reactivate the page. 2666 */ 2667 vm_page_aflag_clear(m, PGA_REFERENCED); 2668 2669 if (advice != MADV_FREE && m->dirty == 0 && pmap_is_modified(m)) 2670 vm_page_dirty(m); 2671 2672 if (m->dirty || (dnw & 0x0070) == 0) { 2673 /* 2674 * Deactivate the page 3 times out of 32. 2675 */ 2676 head = 0; 2677 } else { 2678 /* 2679 * Cache the page 28 times out of every 32. Note that 2680 * the page is deactivated instead of cached, but placed 2681 * at the head of the queue instead of the tail. 2682 */ 2683 head = 1; 2684 } 2685 _vm_page_deactivate(m, head); 2686 } 2687 2688 /* 2689 * Grab a page, waiting until we are waken up due to the page 2690 * changing state. We keep on waiting, if the page continues 2691 * to be in the object. If the page doesn't exist, first allocate it 2692 * and then conditionally zero it. 2693 * 2694 * This routine may sleep. 2695 * 2696 * The object must be locked on entry. The lock will, however, be released 2697 * and reacquired if the routine sleeps. 2698 */ 2699 vm_page_t 2700 vm_page_grab(vm_object_t object, vm_pindex_t pindex, int allocflags) 2701 { 2702 vm_page_t m; 2703 int sleep; 2704 2705 VM_OBJECT_ASSERT_WLOCKED(object); 2706 KASSERT((allocflags & VM_ALLOC_SBUSY) == 0 || 2707 (allocflags & VM_ALLOC_IGN_SBUSY) != 0, 2708 ("vm_page_grab: VM_ALLOC_SBUSY/VM_ALLOC_IGN_SBUSY mismatch")); 2709 retrylookup: 2710 if ((m = vm_page_lookup(object, pindex)) != NULL) { 2711 sleep = (allocflags & VM_ALLOC_IGN_SBUSY) != 0 ? 2712 vm_page_xbusied(m) : vm_page_busied(m); 2713 if (sleep) { 2714 if ((allocflags & VM_ALLOC_NOWAIT) != 0) 2715 return (NULL); 2716 /* 2717 * Reference the page before unlocking and 2718 * sleeping so that the page daemon is less 2719 * likely to reclaim it. 2720 */ 2721 vm_page_aflag_set(m, PGA_REFERENCED); 2722 vm_page_lock(m); 2723 VM_OBJECT_WUNLOCK(object); 2724 vm_page_busy_sleep(m, "pgrbwt"); 2725 VM_OBJECT_WLOCK(object); 2726 goto retrylookup; 2727 } else { 2728 if ((allocflags & VM_ALLOC_WIRED) != 0) { 2729 vm_page_lock(m); 2730 vm_page_wire(m); 2731 vm_page_unlock(m); 2732 } 2733 if ((allocflags & 2734 (VM_ALLOC_NOBUSY | VM_ALLOC_SBUSY)) == 0) 2735 vm_page_xbusy(m); 2736 if ((allocflags & VM_ALLOC_SBUSY) != 0) 2737 vm_page_sbusy(m); 2738 return (m); 2739 } 2740 } 2741 m = vm_page_alloc(object, pindex, allocflags); 2742 if (m == NULL) { 2743 if ((allocflags & VM_ALLOC_NOWAIT) != 0) 2744 return (NULL); 2745 VM_OBJECT_WUNLOCK(object); 2746 VM_WAIT; 2747 VM_OBJECT_WLOCK(object); 2748 goto retrylookup; 2749 } else if (m->valid != 0) 2750 return (m); 2751 if (allocflags & VM_ALLOC_ZERO && (m->flags & PG_ZERO) == 0) 2752 pmap_zero_page(m); 2753 return (m); 2754 } 2755 2756 /* 2757 * Mapping function for valid or dirty bits in a page. 2758 * 2759 * Inputs are required to range within a page. 2760 */ 2761 vm_page_bits_t 2762 vm_page_bits(int base, int size) 2763 { 2764 int first_bit; 2765 int last_bit; 2766 2767 KASSERT( 2768 base + size <= PAGE_SIZE, 2769 ("vm_page_bits: illegal base/size %d/%d", base, size) 2770 ); 2771 2772 if (size == 0) /* handle degenerate case */ 2773 return (0); 2774 2775 first_bit = base >> DEV_BSHIFT; 2776 last_bit = (base + size - 1) >> DEV_BSHIFT; 2777 2778 return (((vm_page_bits_t)2 << last_bit) - 2779 ((vm_page_bits_t)1 << first_bit)); 2780 } 2781 2782 /* 2783 * vm_page_set_valid_range: 2784 * 2785 * Sets portions of a page valid. The arguments are expected 2786 * to be DEV_BSIZE aligned but if they aren't the bitmap is inclusive 2787 * of any partial chunks touched by the range. The invalid portion of 2788 * such chunks will be zeroed. 2789 * 2790 * (base + size) must be less then or equal to PAGE_SIZE. 2791 */ 2792 void 2793 vm_page_set_valid_range(vm_page_t m, int base, int size) 2794 { 2795 int endoff, frag; 2796 2797 VM_OBJECT_ASSERT_WLOCKED(m->object); 2798 if (size == 0) /* handle degenerate case */ 2799 return; 2800 2801 /* 2802 * If the base is not DEV_BSIZE aligned and the valid 2803 * bit is clear, we have to zero out a portion of the 2804 * first block. 2805 */ 2806 if ((frag = base & ~(DEV_BSIZE - 1)) != base && 2807 (m->valid & (1 << (base >> DEV_BSHIFT))) == 0) 2808 pmap_zero_page_area(m, frag, base - frag); 2809 2810 /* 2811 * If the ending offset is not DEV_BSIZE aligned and the 2812 * valid bit is clear, we have to zero out a portion of 2813 * the last block. 2814 */ 2815 endoff = base + size; 2816 if ((frag = endoff & ~(DEV_BSIZE - 1)) != endoff && 2817 (m->valid & (1 << (endoff >> DEV_BSHIFT))) == 0) 2818 pmap_zero_page_area(m, endoff, 2819 DEV_BSIZE - (endoff & (DEV_BSIZE - 1))); 2820 2821 /* 2822 * Assert that no previously invalid block that is now being validated 2823 * is already dirty. 2824 */ 2825 KASSERT((~m->valid & vm_page_bits(base, size) & m->dirty) == 0, 2826 ("vm_page_set_valid_range: page %p is dirty", m)); 2827 2828 /* 2829 * Set valid bits inclusive of any overlap. 2830 */ 2831 m->valid |= vm_page_bits(base, size); 2832 } 2833 2834 /* 2835 * Clear the given bits from the specified page's dirty field. 2836 */ 2837 static __inline void 2838 vm_page_clear_dirty_mask(vm_page_t m, vm_page_bits_t pagebits) 2839 { 2840 uintptr_t addr; 2841 #if PAGE_SIZE < 16384 2842 int shift; 2843 #endif 2844 2845 /* 2846 * If the object is locked and the page is neither exclusive busy nor 2847 * write mapped, then the page's dirty field cannot possibly be 2848 * set by a concurrent pmap operation. 2849 */ 2850 VM_OBJECT_ASSERT_WLOCKED(m->object); 2851 if (!vm_page_xbusied(m) && !pmap_page_is_write_mapped(m)) 2852 m->dirty &= ~pagebits; 2853 else { 2854 /* 2855 * The pmap layer can call vm_page_dirty() without 2856 * holding a distinguished lock. The combination of 2857 * the object's lock and an atomic operation suffice 2858 * to guarantee consistency of the page dirty field. 2859 * 2860 * For PAGE_SIZE == 32768 case, compiler already 2861 * properly aligns the dirty field, so no forcible 2862 * alignment is needed. Only require existence of 2863 * atomic_clear_64 when page size is 32768. 2864 */ 2865 addr = (uintptr_t)&m->dirty; 2866 #if PAGE_SIZE == 32768 2867 atomic_clear_64((uint64_t *)addr, pagebits); 2868 #elif PAGE_SIZE == 16384 2869 atomic_clear_32((uint32_t *)addr, pagebits); 2870 #else /* PAGE_SIZE <= 8192 */ 2871 /* 2872 * Use a trick to perform a 32-bit atomic on the 2873 * containing aligned word, to not depend on the existence 2874 * of atomic_clear_{8, 16}. 2875 */ 2876 shift = addr & (sizeof(uint32_t) - 1); 2877 #if BYTE_ORDER == BIG_ENDIAN 2878 shift = (sizeof(uint32_t) - sizeof(m->dirty) - shift) * NBBY; 2879 #else 2880 shift *= NBBY; 2881 #endif 2882 addr &= ~(sizeof(uint32_t) - 1); 2883 atomic_clear_32((uint32_t *)addr, pagebits << shift); 2884 #endif /* PAGE_SIZE */ 2885 } 2886 } 2887 2888 /* 2889 * vm_page_set_validclean: 2890 * 2891 * Sets portions of a page valid and clean. The arguments are expected 2892 * to be DEV_BSIZE aligned but if they aren't the bitmap is inclusive 2893 * of any partial chunks touched by the range. The invalid portion of 2894 * such chunks will be zero'd. 2895 * 2896 * (base + size) must be less then or equal to PAGE_SIZE. 2897 */ 2898 void 2899 vm_page_set_validclean(vm_page_t m, int base, int size) 2900 { 2901 vm_page_bits_t oldvalid, pagebits; 2902 int endoff, frag; 2903 2904 VM_OBJECT_ASSERT_WLOCKED(m->object); 2905 if (size == 0) /* handle degenerate case */ 2906 return; 2907 2908 /* 2909 * If the base is not DEV_BSIZE aligned and the valid 2910 * bit is clear, we have to zero out a portion of the 2911 * first block. 2912 */ 2913 if ((frag = base & ~(DEV_BSIZE - 1)) != base && 2914 (m->valid & ((vm_page_bits_t)1 << (base >> DEV_BSHIFT))) == 0) 2915 pmap_zero_page_area(m, frag, base - frag); 2916 2917 /* 2918 * If the ending offset is not DEV_BSIZE aligned and the 2919 * valid bit is clear, we have to zero out a portion of 2920 * the last block. 2921 */ 2922 endoff = base + size; 2923 if ((frag = endoff & ~(DEV_BSIZE - 1)) != endoff && 2924 (m->valid & ((vm_page_bits_t)1 << (endoff >> DEV_BSHIFT))) == 0) 2925 pmap_zero_page_area(m, endoff, 2926 DEV_BSIZE - (endoff & (DEV_BSIZE - 1))); 2927 2928 /* 2929 * Set valid, clear dirty bits. If validating the entire 2930 * page we can safely clear the pmap modify bit. We also 2931 * use this opportunity to clear the VPO_NOSYNC flag. If a process 2932 * takes a write fault on a MAP_NOSYNC memory area the flag will 2933 * be set again. 2934 * 2935 * We set valid bits inclusive of any overlap, but we can only 2936 * clear dirty bits for DEV_BSIZE chunks that are fully within 2937 * the range. 2938 */ 2939 oldvalid = m->valid; 2940 pagebits = vm_page_bits(base, size); 2941 m->valid |= pagebits; 2942 #if 0 /* NOT YET */ 2943 if ((frag = base & (DEV_BSIZE - 1)) != 0) { 2944 frag = DEV_BSIZE - frag; 2945 base += frag; 2946 size -= frag; 2947 if (size < 0) 2948 size = 0; 2949 } 2950 pagebits = vm_page_bits(base, size & (DEV_BSIZE - 1)); 2951 #endif 2952 if (base == 0 && size == PAGE_SIZE) { 2953 /* 2954 * The page can only be modified within the pmap if it is 2955 * mapped, and it can only be mapped if it was previously 2956 * fully valid. 2957 */ 2958 if (oldvalid == VM_PAGE_BITS_ALL) 2959 /* 2960 * Perform the pmap_clear_modify() first. Otherwise, 2961 * a concurrent pmap operation, such as 2962 * pmap_protect(), could clear a modification in the 2963 * pmap and set the dirty field on the page before 2964 * pmap_clear_modify() had begun and after the dirty 2965 * field was cleared here. 2966 */ 2967 pmap_clear_modify(m); 2968 m->dirty = 0; 2969 m->oflags &= ~VPO_NOSYNC; 2970 } else if (oldvalid != VM_PAGE_BITS_ALL) 2971 m->dirty &= ~pagebits; 2972 else 2973 vm_page_clear_dirty_mask(m, pagebits); 2974 } 2975 2976 void 2977 vm_page_clear_dirty(vm_page_t m, int base, int size) 2978 { 2979 2980 vm_page_clear_dirty_mask(m, vm_page_bits(base, size)); 2981 } 2982 2983 /* 2984 * vm_page_set_invalid: 2985 * 2986 * Invalidates DEV_BSIZE'd chunks within a page. Both the 2987 * valid and dirty bits for the effected areas are cleared. 2988 */ 2989 void 2990 vm_page_set_invalid(vm_page_t m, int base, int size) 2991 { 2992 vm_page_bits_t bits; 2993 vm_object_t object; 2994 2995 object = m->object; 2996 VM_OBJECT_ASSERT_WLOCKED(object); 2997 if (object->type == OBJT_VNODE && base == 0 && IDX_TO_OFF(m->pindex) + 2998 size >= object->un_pager.vnp.vnp_size) 2999 bits = VM_PAGE_BITS_ALL; 3000 else 3001 bits = vm_page_bits(base, size); 3002 if (m->valid == VM_PAGE_BITS_ALL && bits != 0) 3003 pmap_remove_all(m); 3004 KASSERT((bits == 0 && m->valid == VM_PAGE_BITS_ALL) || 3005 !pmap_page_is_mapped(m), 3006 ("vm_page_set_invalid: page %p is mapped", m)); 3007 m->valid &= ~bits; 3008 m->dirty &= ~bits; 3009 } 3010 3011 /* 3012 * vm_page_zero_invalid() 3013 * 3014 * The kernel assumes that the invalid portions of a page contain 3015 * garbage, but such pages can be mapped into memory by user code. 3016 * When this occurs, we must zero out the non-valid portions of the 3017 * page so user code sees what it expects. 3018 * 3019 * Pages are most often semi-valid when the end of a file is mapped 3020 * into memory and the file's size is not page aligned. 3021 */ 3022 void 3023 vm_page_zero_invalid(vm_page_t m, boolean_t setvalid) 3024 { 3025 int b; 3026 int i; 3027 3028 VM_OBJECT_ASSERT_WLOCKED(m->object); 3029 /* 3030 * Scan the valid bits looking for invalid sections that 3031 * must be zerod. Invalid sub-DEV_BSIZE'd areas ( where the 3032 * valid bit may be set ) have already been zerod by 3033 * vm_page_set_validclean(). 3034 */ 3035 for (b = i = 0; i <= PAGE_SIZE / DEV_BSIZE; ++i) { 3036 if (i == (PAGE_SIZE / DEV_BSIZE) || 3037 (m->valid & ((vm_page_bits_t)1 << i))) { 3038 if (i > b) { 3039 pmap_zero_page_area(m, 3040 b << DEV_BSHIFT, (i - b) << DEV_BSHIFT); 3041 } 3042 b = i + 1; 3043 } 3044 } 3045 3046 /* 3047 * setvalid is TRUE when we can safely set the zero'd areas 3048 * as being valid. We can do this if there are no cache consistancy 3049 * issues. e.g. it is ok to do with UFS, but not ok to do with NFS. 3050 */ 3051 if (setvalid) 3052 m->valid = VM_PAGE_BITS_ALL; 3053 } 3054 3055 /* 3056 * vm_page_is_valid: 3057 * 3058 * Is (partial) page valid? Note that the case where size == 0 3059 * will return FALSE in the degenerate case where the page is 3060 * entirely invalid, and TRUE otherwise. 3061 */ 3062 int 3063 vm_page_is_valid(vm_page_t m, int base, int size) 3064 { 3065 vm_page_bits_t bits; 3066 3067 VM_OBJECT_ASSERT_LOCKED(m->object); 3068 bits = vm_page_bits(base, size); 3069 return (m->valid != 0 && (m->valid & bits) == bits); 3070 } 3071 3072 /* 3073 * vm_page_ps_is_valid: 3074 * 3075 * Returns TRUE if the entire (super)page is valid and FALSE otherwise. 3076 */ 3077 boolean_t 3078 vm_page_ps_is_valid(vm_page_t m) 3079 { 3080 int i, npages; 3081 3082 VM_OBJECT_ASSERT_LOCKED(m->object); 3083 npages = atop(pagesizes[m->psind]); 3084 3085 /* 3086 * The physically contiguous pages that make up a superpage, i.e., a 3087 * page with a page size index ("psind") greater than zero, will 3088 * occupy adjacent entries in vm_page_array[]. 3089 */ 3090 for (i = 0; i < npages; i++) { 3091 if (m[i].valid != VM_PAGE_BITS_ALL) 3092 return (FALSE); 3093 } 3094 return (TRUE); 3095 } 3096 3097 /* 3098 * Set the page's dirty bits if the page is modified. 3099 */ 3100 void 3101 vm_page_test_dirty(vm_page_t m) 3102 { 3103 3104 VM_OBJECT_ASSERT_WLOCKED(m->object); 3105 if (m->dirty != VM_PAGE_BITS_ALL && pmap_is_modified(m)) 3106 vm_page_dirty(m); 3107 } 3108 3109 void 3110 vm_page_lock_KBI(vm_page_t m, const char *file, int line) 3111 { 3112 3113 mtx_lock_flags_(vm_page_lockptr(m), 0, file, line); 3114 } 3115 3116 void 3117 vm_page_unlock_KBI(vm_page_t m, const char *file, int line) 3118 { 3119 3120 mtx_unlock_flags_(vm_page_lockptr(m), 0, file, line); 3121 } 3122 3123 int 3124 vm_page_trylock_KBI(vm_page_t m, const char *file, int line) 3125 { 3126 3127 return (mtx_trylock_flags_(vm_page_lockptr(m), 0, file, line)); 3128 } 3129 3130 #if defined(INVARIANTS) || defined(INVARIANT_SUPPORT) 3131 void 3132 vm_page_assert_locked_KBI(vm_page_t m, const char *file, int line) 3133 { 3134 3135 vm_page_lock_assert_KBI(m, MA_OWNED, file, line); 3136 } 3137 3138 void 3139 vm_page_lock_assert_KBI(vm_page_t m, int a, const char *file, int line) 3140 { 3141 3142 mtx_assert_(vm_page_lockptr(m), a, file, line); 3143 } 3144 #endif 3145 3146 #ifdef INVARIANTS 3147 void 3148 vm_page_object_lock_assert(vm_page_t m) 3149 { 3150 3151 /* 3152 * Certain of the page's fields may only be modified by the 3153 * holder of the containing object's lock or the exclusive busy. 3154 * holder. Unfortunately, the holder of the write busy is 3155 * not recorded, and thus cannot be checked here. 3156 */ 3157 if (m->object != NULL && !vm_page_xbusied(m)) 3158 VM_OBJECT_ASSERT_WLOCKED(m->object); 3159 } 3160 3161 void 3162 vm_page_assert_pga_writeable(vm_page_t m, uint8_t bits) 3163 { 3164 3165 if ((bits & PGA_WRITEABLE) == 0) 3166 return; 3167 3168 /* 3169 * The PGA_WRITEABLE flag can only be set if the page is 3170 * managed, is exclusively busied or the object is locked. 3171 * Currently, this flag is only set by pmap_enter(). 3172 */ 3173 KASSERT((m->oflags & VPO_UNMANAGED) == 0, 3174 ("PGA_WRITEABLE on unmanaged page")); 3175 if (!vm_page_xbusied(m)) 3176 VM_OBJECT_ASSERT_LOCKED(m->object); 3177 } 3178 #endif 3179 3180 #include "opt_ddb.h" 3181 #ifdef DDB 3182 #include <sys/kernel.h> 3183 3184 #include <ddb/ddb.h> 3185 3186 DB_SHOW_COMMAND(page, vm_page_print_page_info) 3187 { 3188 db_printf("vm_cnt.v_free_count: %d\n", vm_cnt.v_free_count); 3189 db_printf("vm_cnt.v_cache_count: %d\n", vm_cnt.v_cache_count); 3190 db_printf("vm_cnt.v_inactive_count: %d\n", vm_cnt.v_inactive_count); 3191 db_printf("vm_cnt.v_active_count: %d\n", vm_cnt.v_active_count); 3192 db_printf("vm_cnt.v_wire_count: %d\n", vm_cnt.v_wire_count); 3193 db_printf("vm_cnt.v_free_reserved: %d\n", vm_cnt.v_free_reserved); 3194 db_printf("vm_cnt.v_free_min: %d\n", vm_cnt.v_free_min); 3195 db_printf("vm_cnt.v_free_target: %d\n", vm_cnt.v_free_target); 3196 db_printf("vm_cnt.v_cache_min: %d\n", vm_cnt.v_cache_min); 3197 db_printf("vm_cnt.v_inactive_target: %d\n", vm_cnt.v_inactive_target); 3198 } 3199 3200 DB_SHOW_COMMAND(pageq, vm_page_print_pageq_info) 3201 { 3202 int dom; 3203 3204 db_printf("pq_free %d pq_cache %d\n", 3205 vm_cnt.v_free_count, vm_cnt.v_cache_count); 3206 for (dom = 0; dom < vm_ndomains; dom++) { 3207 db_printf( 3208 "dom %d page_cnt %d free %d pq_act %d pq_inact %d pass %d\n", 3209 dom, 3210 vm_dom[dom].vmd_page_count, 3211 vm_dom[dom].vmd_free_count, 3212 vm_dom[dom].vmd_pagequeues[PQ_ACTIVE].pq_cnt, 3213 vm_dom[dom].vmd_pagequeues[PQ_INACTIVE].pq_cnt, 3214 vm_dom[dom].vmd_pass); 3215 } 3216 } 3217 3218 DB_SHOW_COMMAND(pginfo, vm_page_print_pginfo) 3219 { 3220 vm_page_t m; 3221 boolean_t phys; 3222 3223 if (!have_addr) { 3224 db_printf("show pginfo addr\n"); 3225 return; 3226 } 3227 3228 phys = strchr(modif, 'p') != NULL; 3229 if (phys) 3230 m = PHYS_TO_VM_PAGE(addr); 3231 else 3232 m = (vm_page_t)addr; 3233 db_printf( 3234 "page %p obj %p pidx 0x%jx phys 0x%jx q %d hold %d wire %d\n" 3235 " af 0x%x of 0x%x f 0x%x act %d busy %x valid 0x%x dirty 0x%x\n", 3236 m, m->object, (uintmax_t)m->pindex, (uintmax_t)m->phys_addr, 3237 m->queue, m->hold_count, m->wire_count, m->aflags, m->oflags, 3238 m->flags, m->act_count, m->busy_lock, m->valid, m->dirty); 3239 } 3240 #endif /* DDB */ 3241