234 235 /* 236 * Compute the number of pages of memory that will be available for 237 * use (taking into account the overhead of a page structure per 238 * page). 239 */ 240 first_page = phys_avail[0] / PAGE_SIZE; 241 page_range = phys_avail[(nblocks - 1) * 2 + 1] / PAGE_SIZE - first_page; 242 npages = (total - (page_range * sizeof(struct vm_page)) - 243 (end - new_end)) / PAGE_SIZE; 244 end = new_end; 245 246 /* 247 * Reserve an unmapped guard page to trap access to vm_page_array[-1]. 248 */ 249 vaddr += PAGE_SIZE; 250 251 /* 252 * Initialize the mem entry structures now, and put them in the free 253 * queue. 254 */ 255 new_end = trunc_page(end - page_range * sizeof(struct vm_page)); 256 mapped = pmap_map(&vaddr, new_end, end, 257 VM_PROT_READ | VM_PROT_WRITE); 258 vm_page_array = (vm_page_t) mapped; 259 phys_avail[biggestone + 1] = new_end; 260 261 /* 262 * Clear all of the page structures 263 */ 264 bzero((caddr_t) vm_page_array, page_range * sizeof(struct vm_page)); 265 vm_page_array_size = page_range; 266 267 /* 268 * Construct the free queue(s) in descending order (by physical 269 * address) so that the first 16MB of physical memory is allocated 270 * last rather than first. On large-memory machines, this avoids 271 * the exhaustion of low physical memory before isa_dma_init has run. 272 */ 273 cnt.v_page_count = 0; 274 cnt.v_free_count = 0; 275 for (i = 0; phys_avail[i + 1] && npages > 0; i += 2) { 276 pa = phys_avail[i]; 277 last_pa = phys_avail[i + 1]; 278 while (pa < last_pa && npages-- > 0) { 279 vm_pageq_add_new_page(pa); 280 pa += PAGE_SIZE; 281 } 282 } 283 return (vaddr); 284} 285 286void 287vm_page_flag_set(vm_page_t m, unsigned short bits) 288{ 289 290 mtx_assert(&vm_page_queue_mtx, MA_OWNED); 291 m->flags |= bits; 292} 293 294void 295vm_page_flag_clear(vm_page_t m, unsigned short bits) 296{ 297 298 mtx_assert(&vm_page_queue_mtx, MA_OWNED); 299 m->flags &= ~bits; 300} 301 302void 303vm_page_busy(vm_page_t m) 304{ 305 306 VM_OBJECT_LOCK_ASSERT(m->object, MA_OWNED); 307 KASSERT((m->flags & PG_BUSY) == 0, 308 ("vm_page_busy: page already busy!!!")); 309 vm_page_flag_set(m, PG_BUSY); 310} 311 312/* 313 * vm_page_flash: 314 * 315 * wakeup anyone waiting for the page. 316 */ 317void 318vm_page_flash(vm_page_t m) 319{ 320 321 VM_OBJECT_LOCK_ASSERT(m->object, MA_OWNED); 322 if (m->flags & PG_WANTED) { 323 vm_page_flag_clear(m, PG_WANTED); 324 wakeup(m); 325 } 326} 327 328/* 329 * vm_page_wakeup: 330 * 331 * clear the PG_BUSY flag and wakeup anyone waiting for the 332 * page. 333 * 334 */ 335void 336vm_page_wakeup(vm_page_t m) 337{ 338 339 VM_OBJECT_LOCK_ASSERT(m->object, MA_OWNED); 340 KASSERT(m->flags & PG_BUSY, ("vm_page_wakeup: page not busy!!!")); 341 vm_page_flag_clear(m, PG_BUSY); 342 vm_page_flash(m); 343} 344 345void 346vm_page_io_start(vm_page_t m) 347{ 348 349 VM_OBJECT_LOCK_ASSERT(m->object, MA_OWNED); 350 m->busy++; 351} 352 353void 354vm_page_io_finish(vm_page_t m) 355{ 356 357 VM_OBJECT_LOCK_ASSERT(m->object, MA_OWNED); 358 mtx_assert(&vm_page_queue_mtx, MA_OWNED); 359 m->busy--; 360 if (m->busy == 0) 361 vm_page_flash(m); 362} 363 364/* 365 * Keep page from being freed by the page daemon 366 * much of the same effect as wiring, except much lower 367 * overhead and should be used only for *very* temporary 368 * holding ("wiring"). 369 */ 370void 371vm_page_hold(vm_page_t mem) 372{ 373 374 mtx_assert(&vm_page_queue_mtx, MA_OWNED); 375 mem->hold_count++; 376} 377 378void 379vm_page_unhold(vm_page_t mem) 380{ 381 382 mtx_assert(&vm_page_queue_mtx, MA_OWNED); 383 --mem->hold_count; 384 KASSERT(mem->hold_count >= 0, ("vm_page_unhold: hold count < 0!!!")); 385 if (mem->hold_count == 0 && mem->queue == PQ_HOLD) 386 vm_page_free_toq(mem); 387} 388 389/* 390 * vm_page_free: 391 * 392 * Free a page 393 * 394 * The clearing of PG_ZERO is a temporary safety until the code can be 395 * reviewed to determine that PG_ZERO is being properly cleared on 396 * write faults or maps. PG_ZERO was previously cleared in 397 * vm_page_alloc(). 398 */ 399void 400vm_page_free(vm_page_t m) 401{ 402 vm_page_flag_clear(m, PG_ZERO); 403 vm_page_free_toq(m); 404 vm_page_zero_idle_wakeup(); 405} 406 407/* 408 * vm_page_free_zero: 409 * 410 * Free a page to the zerod-pages queue 411 */ 412void 413vm_page_free_zero(vm_page_t m) 414{ 415 vm_page_flag_set(m, PG_ZERO); 416 vm_page_free_toq(m); 417} 418 419/* 420 * vm_page_sleep_if_busy: 421 * 422 * Sleep and release the page queues lock if PG_BUSY is set or, 423 * if also_m_busy is TRUE, busy is non-zero. Returns TRUE if the 424 * thread slept and the page queues lock was released. 425 * Otherwise, retains the page queues lock and returns FALSE. 426 */ 427int 428vm_page_sleep_if_busy(vm_page_t m, int also_m_busy, const char *msg) 429{ 430 vm_object_t object; 431 432 mtx_assert(&vm_page_queue_mtx, MA_OWNED); 433 VM_OBJECT_LOCK_ASSERT(m->object, MA_OWNED); 434 if ((m->flags & PG_BUSY) || (also_m_busy && m->busy)) { 435 vm_page_flag_set(m, PG_WANTED | PG_REFERENCED); 436 /* 437 * It's possible that while we sleep, the page will get 438 * unbusied and freed. If we are holding the object 439 * lock, we will assume we hold a reference to the object 440 * such that even if m->object changes, we can re-lock 441 * it. 442 */ 443 object = m->object; 444 VM_OBJECT_UNLOCK(object); 445 msleep(m, &vm_page_queue_mtx, PDROP | PVM, msg, 0); 446 VM_OBJECT_LOCK(object); 447 return (TRUE); 448 } 449 return (FALSE); 450} 451 452/* 453 * vm_page_dirty: 454 * 455 * make page all dirty 456 */ 457void 458vm_page_dirty(vm_page_t m) 459{ 460 KASSERT(m->queue - m->pc != PQ_CACHE, 461 ("vm_page_dirty: page in cache!")); 462 KASSERT(m->queue - m->pc != PQ_FREE, 463 ("vm_page_dirty: page is free!")); 464 m->dirty = VM_PAGE_BITS_ALL; 465} 466 467/* 468 * vm_page_splay: 469 * 470 * Implements Sleator and Tarjan's top-down splay algorithm. Returns 471 * the vm_page containing the given pindex. If, however, that 472 * pindex is not found in the vm_object, returns a vm_page that is 473 * adjacent to the pindex, coming before or after it. 474 */ 475vm_page_t 476vm_page_splay(vm_pindex_t pindex, vm_page_t root) 477{ 478 struct vm_page dummy; 479 vm_page_t lefttreemax, righttreemin, y; 480 481 if (root == NULL) 482 return (root); 483 lefttreemax = righttreemin = &dummy; 484 for (;; root = y) { 485 if (pindex < root->pindex) { 486 if ((y = root->left) == NULL) 487 break; 488 if (pindex < y->pindex) { 489 /* Rotate right. */ 490 root->left = y->right; 491 y->right = root; 492 root = y; 493 if ((y = root->left) == NULL) 494 break; 495 } 496 /* Link into the new root's right tree. */ 497 righttreemin->left = root; 498 righttreemin = root; 499 } else if (pindex > root->pindex) { 500 if ((y = root->right) == NULL) 501 break; 502 if (pindex > y->pindex) { 503 /* Rotate left. */ 504 root->right = y->left; 505 y->left = root; 506 root = y; 507 if ((y = root->right) == NULL) 508 break; 509 } 510 /* Link into the new root's left tree. */ 511 lefttreemax->right = root; 512 lefttreemax = root; 513 } else 514 break; 515 } 516 /* Assemble the new root. */ 517 lefttreemax->right = root->left; 518 righttreemin->left = root->right; 519 root->left = dummy.right; 520 root->right = dummy.left; 521 return (root); 522} 523 524/* 525 * vm_page_insert: [ internal use only ] 526 * 527 * Inserts the given mem entry into the object and object list. 528 * 529 * The pagetables are not updated but will presumably fault the page 530 * in if necessary, or if a kernel page the caller will at some point 531 * enter the page into the kernel's pmap. We are not allowed to block 532 * here so we *can't* do this anyway. 533 * 534 * The object and page must be locked. 535 * This routine may not block. 536 */ 537void 538vm_page_insert(vm_page_t m, vm_object_t object, vm_pindex_t pindex) 539{ 540 vm_page_t root; 541 542 VM_OBJECT_LOCK_ASSERT(object, MA_OWNED); 543 if (m->object != NULL) 544 panic("vm_page_insert: page already inserted"); 545 546 /* 547 * Record the object/offset pair in this page 548 */ 549 m->object = object; 550 m->pindex = pindex; 551 552 /* 553 * Now link into the object's ordered list of backed pages. 554 */ 555 root = object->root; 556 if (root == NULL) { 557 m->left = NULL; 558 m->right = NULL; 559 TAILQ_INSERT_TAIL(&object->memq, m, listq); 560 } else { 561 root = vm_page_splay(pindex, root); 562 if (pindex < root->pindex) { 563 m->left = root->left; 564 m->right = root; 565 root->left = NULL; 566 TAILQ_INSERT_BEFORE(root, m, listq); 567 } else if (pindex == root->pindex) 568 panic("vm_page_insert: offset already allocated"); 569 else { 570 m->right = root->right; 571 m->left = root; 572 root->right = NULL; 573 TAILQ_INSERT_AFTER(&object->memq, root, m, listq); 574 } 575 } 576 object->root = m; 577 object->generation++; 578 579 /* 580 * show that the object has one more resident page. 581 */ 582 object->resident_page_count++; 583 /* 584 * Hold the vnode until the last page is released. 585 */ 586 if (object->resident_page_count == 1 && object->type == OBJT_VNODE) 587 vhold((struct vnode *)object->handle); 588 589 /* 590 * Since we are inserting a new and possibly dirty page, 591 * update the object's OBJ_WRITEABLE and OBJ_MIGHTBEDIRTY flags. 592 */ 593 if (m->flags & PG_WRITEABLE) 594 vm_object_set_writeable_dirty(object); 595} 596 597/* 598 * vm_page_remove: 599 * NOTE: used by device pager as well -wfj 600 * 601 * Removes the given mem entry from the object/offset-page 602 * table and the object page list, but do not invalidate/terminate 603 * the backing store. 604 * 605 * The object and page must be locked. 606 * The underlying pmap entry (if any) is NOT removed here. 607 * This routine may not block. 608 */ 609void 610vm_page_remove(vm_page_t m) 611{ 612 vm_object_t object; 613 vm_page_t root; 614 615 mtx_assert(&vm_page_queue_mtx, MA_OWNED); 616 if ((object = m->object) == NULL) 617 return; 618 VM_OBJECT_LOCK_ASSERT(object, MA_OWNED); 619 if (m->flags & PG_BUSY) { 620 vm_page_flag_clear(m, PG_BUSY); 621 vm_page_flash(m); 622 } 623 624 /* 625 * Now remove from the object's list of backed pages. 626 */ 627 if (m != object->root) 628 vm_page_splay(m->pindex, object->root); 629 if (m->left == NULL) 630 root = m->right; 631 else { 632 root = vm_page_splay(m->pindex, m->left); 633 root->right = m->right; 634 } 635 object->root = root; 636 TAILQ_REMOVE(&object->memq, m, listq); 637 638 /* 639 * And show that the object has one fewer resident page. 640 */ 641 object->resident_page_count--; 642 object->generation++; 643 /* 644 * The vnode may now be recycled. 645 */ 646 if (object->resident_page_count == 0 && object->type == OBJT_VNODE) 647 vdrop((struct vnode *)object->handle); 648 649 m->object = NULL; 650} 651 652/* 653 * vm_page_lookup: 654 * 655 * Returns the page associated with the object/offset 656 * pair specified; if none is found, NULL is returned. 657 * 658 * The object must be locked. 659 * This routine may not block. 660 * This is a critical path routine 661 */ 662vm_page_t 663vm_page_lookup(vm_object_t object, vm_pindex_t pindex) 664{ 665 vm_page_t m; 666 667 VM_OBJECT_LOCK_ASSERT(object, MA_OWNED); 668 if ((m = object->root) != NULL && m->pindex != pindex) { 669 m = vm_page_splay(pindex, m); 670 if ((object->root = m)->pindex != pindex) 671 m = NULL; 672 } 673 return (m); 674} 675 676/* 677 * vm_page_rename: 678 * 679 * Move the given memory entry from its 680 * current object to the specified target object/offset. 681 * 682 * The object must be locked. 683 * This routine may not block. 684 * 685 * Note: swap associated with the page must be invalidated by the move. We 686 * have to do this for several reasons: (1) we aren't freeing the 687 * page, (2) we are dirtying the page, (3) the VM system is probably 688 * moving the page from object A to B, and will then later move 689 * the backing store from A to B and we can't have a conflict. 690 * 691 * Note: we *always* dirty the page. It is necessary both for the 692 * fact that we moved it, and because we may be invalidating 693 * swap. If the page is on the cache, we have to deactivate it 694 * or vm_page_dirty() will panic. Dirty pages are not allowed 695 * on the cache. 696 */ 697void 698vm_page_rename(vm_page_t m, vm_object_t new_object, vm_pindex_t new_pindex) 699{ 700 701 vm_page_remove(m); 702 vm_page_insert(m, new_object, new_pindex); 703 if (m->queue - m->pc == PQ_CACHE) 704 vm_page_deactivate(m); 705 vm_page_dirty(m); 706} 707 708/* 709 * vm_page_select_cache: 710 * 711 * Move a page of the given color from the cache queue to the free 712 * queue. As pages might be found, but are not applicable, they are 713 * deactivated. 714 * 715 * This routine may not block. 716 */ 717vm_page_t 718vm_page_select_cache(int color) 719{ 720 vm_object_t object; 721 vm_page_t m; 722 boolean_t was_trylocked; 723 724 mtx_assert(&vm_page_queue_mtx, MA_OWNED); 725 while ((m = vm_pageq_find(PQ_CACHE, color, FALSE)) != NULL) { 726 KASSERT(m->dirty == 0, ("Found dirty cache page %p", m)); 727 KASSERT(!pmap_page_is_mapped(m), 728 ("Found mapped cache page %p", m)); 729 KASSERT((m->flags & PG_UNMANAGED) == 0, 730 ("Found unmanaged cache page %p", m)); 731 KASSERT(m->wire_count == 0, ("Found wired cache page %p", m)); 732 if (m->hold_count == 0 && (object = m->object, 733 (was_trylocked = VM_OBJECT_TRYLOCK(object)) || 734 VM_OBJECT_LOCKED(object))) { 735 KASSERT((m->flags & PG_BUSY) == 0 && m->busy == 0, 736 ("Found busy cache page %p", m)); 737 vm_page_free(m); 738 if (was_trylocked) 739 VM_OBJECT_UNLOCK(object); 740 break; 741 } 742 vm_page_deactivate(m); 743 } 744 return (m); 745} 746 747/* 748 * vm_page_alloc: 749 * 750 * Allocate and return a memory cell associated 751 * with this VM object/offset pair. 752 * 753 * page_req classes: 754 * VM_ALLOC_NORMAL normal process request 755 * VM_ALLOC_SYSTEM system *really* needs a page 756 * VM_ALLOC_INTERRUPT interrupt time request 757 * VM_ALLOC_ZERO zero page 758 * 759 * This routine may not block. 760 * 761 * Additional special handling is required when called from an 762 * interrupt (VM_ALLOC_INTERRUPT). We are not allowed to mess with 763 * the page cache in this case. 764 */ 765vm_page_t 766vm_page_alloc(vm_object_t object, vm_pindex_t pindex, int req) 767{ 768 vm_page_t m = NULL; 769 int color, flags, page_req; 770 771 page_req = req & VM_ALLOC_CLASS_MASK; 772 KASSERT(curthread->td_intr_nesting_level == 0 || 773 page_req == VM_ALLOC_INTERRUPT, 774 ("vm_page_alloc(NORMAL|SYSTEM) in interrupt context")); 775 776 if ((req & VM_ALLOC_NOOBJ) == 0) { 777 KASSERT(object != NULL, 778 ("vm_page_alloc: NULL object.")); 779 VM_OBJECT_LOCK_ASSERT(object, MA_OWNED); 780 color = (pindex + object->pg_color) & PQ_L2_MASK; 781 } else 782 color = pindex & PQ_L2_MASK; 783 784 /* 785 * The pager is allowed to eat deeper into the free page list. 786 */ 787 if ((curproc == pageproc) && (page_req != VM_ALLOC_INTERRUPT)) { 788 page_req = VM_ALLOC_SYSTEM; 789 }; 790 791loop: 792 mtx_lock_spin(&vm_page_queue_free_mtx); 793 if (cnt.v_free_count > cnt.v_free_reserved || 794 (page_req == VM_ALLOC_SYSTEM && 795 cnt.v_cache_count == 0 && 796 cnt.v_free_count > cnt.v_interrupt_free_min) || 797 (page_req == VM_ALLOC_INTERRUPT && cnt.v_free_count > 0)) { 798 /* 799 * Allocate from the free queue if the number of free pages 800 * exceeds the minimum for the request class. 801 */ 802 m = vm_pageq_find(PQ_FREE, color, (req & VM_ALLOC_ZERO) != 0); 803 } else if (page_req != VM_ALLOC_INTERRUPT) { 804 mtx_unlock_spin(&vm_page_queue_free_mtx); 805 /* 806 * Allocatable from cache (non-interrupt only). On success, 807 * we must free the page and try again, thus ensuring that 808 * cnt.v_*_free_min counters are replenished. 809 */ 810 vm_page_lock_queues(); 811 if ((m = vm_page_select_cache(color)) == NULL) { 812#if defined(DIAGNOSTIC) 813 if (cnt.v_cache_count > 0) 814 printf("vm_page_alloc(NORMAL): missing pages on cache queue: %d\n", cnt.v_cache_count); 815#endif 816 vm_page_unlock_queues(); 817 atomic_add_int(&vm_pageout_deficit, 1); 818 pagedaemon_wakeup(); 819 return (NULL); 820 } 821 vm_page_unlock_queues(); 822 goto loop; 823 } else { 824 /* 825 * Not allocatable from cache from interrupt, give up. 826 */ 827 mtx_unlock_spin(&vm_page_queue_free_mtx); 828 atomic_add_int(&vm_pageout_deficit, 1); 829 pagedaemon_wakeup(); 830 return (NULL); 831 } 832 833 /* 834 * At this point we had better have found a good page. 835 */ 836 837 KASSERT( 838 m != NULL, 839 ("vm_page_alloc(): missing page on free queue") 840 ); 841 842 /* 843 * Remove from free queue 844 */ 845 vm_pageq_remove_nowakeup(m); 846 847 /* 848 * Initialize structure. Only the PG_ZERO flag is inherited. 849 */ 850 flags = PG_BUSY; 851 if (m->flags & PG_ZERO) { 852 vm_page_zero_count--; 853 if (req & VM_ALLOC_ZERO) 854 flags = PG_ZERO | PG_BUSY; 855 } 856 if (req & (VM_ALLOC_NOBUSY | VM_ALLOC_NOOBJ)) 857 flags &= ~PG_BUSY; 858 m->flags = flags; 859 if (req & VM_ALLOC_WIRED) { 860 atomic_add_int(&cnt.v_wire_count, 1); 861 m->wire_count = 1; 862 } else 863 m->wire_count = 0; 864 m->hold_count = 0; 865 m->act_count = 0; 866 m->busy = 0; 867 m->valid = 0; 868 KASSERT(m->dirty == 0, ("vm_page_alloc: free/cache page %p was dirty", m)); 869 mtx_unlock_spin(&vm_page_queue_free_mtx); 870 871 if ((req & VM_ALLOC_NOOBJ) == 0) 872 vm_page_insert(m, object, pindex); 873 else 874 m->pindex = pindex; 875 876 /* 877 * Don't wakeup too often - wakeup the pageout daemon when 878 * we would be nearly out of memory. 879 */ 880 if (vm_paging_needed()) 881 pagedaemon_wakeup(); 882 883 return (m); 884} 885 886/* 887 * vm_wait: (also see VM_WAIT macro) 888 * 889 * Block until free pages are available for allocation 890 * - Called in various places before memory allocations. 891 */ 892void 893vm_wait(void) 894{ 895 896 vm_page_lock_queues(); 897 if (curproc == pageproc) { 898 vm_pageout_pages_needed = 1; 899 msleep(&vm_pageout_pages_needed, &vm_page_queue_mtx, 900 PDROP | PSWP, "VMWait", 0); 901 } else { 902 if (!vm_pages_needed) { 903 vm_pages_needed = 1; 904 wakeup(&vm_pages_needed); 905 } 906 msleep(&cnt.v_free_count, &vm_page_queue_mtx, PDROP | PVM, 907 "vmwait", 0); 908 } 909} 910 911/* 912 * vm_waitpfault: (also see VM_WAITPFAULT macro) 913 * 914 * Block until free pages are available for allocation 915 * - Called only in vm_fault so that processes page faulting 916 * can be easily tracked. 917 * - Sleeps at a lower priority than vm_wait() so that vm_wait()ing 918 * processes will be able to grab memory first. Do not change 919 * this balance without careful testing first. 920 */ 921void 922vm_waitpfault(void) 923{ 924 925 vm_page_lock_queues(); 926 if (!vm_pages_needed) { 927 vm_pages_needed = 1; 928 wakeup(&vm_pages_needed); 929 } 930 msleep(&cnt.v_free_count, &vm_page_queue_mtx, PDROP | PUSER, 931 "pfault", 0); 932} 933 934/* 935 * vm_page_activate: 936 * 937 * Put the specified page on the active list (if appropriate). 938 * Ensure that act_count is at least ACT_INIT but do not otherwise 939 * mess with it. 940 * 941 * The page queues must be locked. 942 * This routine may not block. 943 */ 944void 945vm_page_activate(vm_page_t m) 946{ 947 948 mtx_assert(&vm_page_queue_mtx, MA_OWNED); 949 if (m->queue != PQ_ACTIVE) { 950 if ((m->queue - m->pc) == PQ_CACHE) 951 cnt.v_reactivated++; 952 vm_pageq_remove(m); 953 if (m->wire_count == 0 && (m->flags & PG_UNMANAGED) == 0) { 954 if (m->act_count < ACT_INIT) 955 m->act_count = ACT_INIT; 956 vm_pageq_enqueue(PQ_ACTIVE, m); 957 } 958 } else { 959 if (m->act_count < ACT_INIT) 960 m->act_count = ACT_INIT; 961 } 962} 963 964/* 965 * vm_page_free_wakeup: 966 * 967 * Helper routine for vm_page_free_toq() and vm_page_cache(). This 968 * routine is called when a page has been added to the cache or free 969 * queues. 970 * 971 * The page queues must be locked. 972 * This routine may not block. 973 */ 974static __inline void 975vm_page_free_wakeup(void) 976{ 977 978 mtx_assert(&vm_page_queue_mtx, MA_OWNED); 979 /* 980 * if pageout daemon needs pages, then tell it that there are 981 * some free. 982 */ 983 if (vm_pageout_pages_needed && 984 cnt.v_cache_count + cnt.v_free_count >= cnt.v_pageout_free_min) { 985 wakeup(&vm_pageout_pages_needed); 986 vm_pageout_pages_needed = 0; 987 } 988 /* 989 * wakeup processes that are waiting on memory if we hit a 990 * high water mark. And wakeup scheduler process if we have 991 * lots of memory. this process will swapin processes. 992 */ 993 if (vm_pages_needed && !vm_page_count_min()) { 994 vm_pages_needed = 0; 995 wakeup(&cnt.v_free_count); 996 } 997} 998 999/* 1000 * vm_page_free_toq: 1001 * 1002 * Returns the given page to the PQ_FREE list, 1003 * disassociating it with any VM object. 1004 * 1005 * Object and page must be locked prior to entry. 1006 * This routine may not block. 1007 */ 1008 1009void 1010vm_page_free_toq(vm_page_t m) 1011{ 1012 struct vpgqueues *pq; 1013 1014 mtx_assert(&vm_page_queue_mtx, MA_OWNED); 1015 cnt.v_tfree++; 1016 1017 if (m->busy || ((m->queue - m->pc) == PQ_FREE)) { 1018 printf( 1019 "vm_page_free: pindex(%lu), busy(%d), PG_BUSY(%d), hold(%d)\n", 1020 (u_long)m->pindex, m->busy, (m->flags & PG_BUSY) ? 1 : 0, 1021 m->hold_count); 1022 if ((m->queue - m->pc) == PQ_FREE) 1023 panic("vm_page_free: freeing free page"); 1024 else 1025 panic("vm_page_free: freeing busy page"); 1026 } 1027 1028 /* 1029 * unqueue, then remove page. Note that we cannot destroy 1030 * the page here because we do not want to call the pager's 1031 * callback routine until after we've put the page on the 1032 * appropriate free queue. 1033 */ 1034 vm_pageq_remove_nowakeup(m); 1035 vm_page_remove(m); 1036 1037 /* 1038 * If fictitious remove object association and 1039 * return, otherwise delay object association removal. 1040 */ 1041 if ((m->flags & PG_FICTITIOUS) != 0) { 1042 return; 1043 } 1044 1045 m->valid = 0; 1046 vm_page_undirty(m); 1047 1048 if (m->wire_count != 0) { 1049 if (m->wire_count > 1) { 1050 panic("vm_page_free: invalid wire count (%d), pindex: 0x%lx", 1051 m->wire_count, (long)m->pindex); 1052 } 1053 panic("vm_page_free: freeing wired page"); 1054 } 1055 1056 /* 1057 * Clear the UNMANAGED flag when freeing an unmanaged page. 1058 */ 1059 if (m->flags & PG_UNMANAGED) { 1060 m->flags &= ~PG_UNMANAGED; 1061 } 1062 1063 if (m->hold_count != 0) { 1064 m->flags &= ~PG_ZERO; 1065 m->queue = PQ_HOLD; 1066 } else 1067 m->queue = PQ_FREE + m->pc; 1068 pq = &vm_page_queues[m->queue]; 1069 mtx_lock_spin(&vm_page_queue_free_mtx); 1070 pq->lcnt++; 1071 ++(*pq->cnt); 1072 1073 /* 1074 * Put zero'd pages on the end ( where we look for zero'd pages 1075 * first ) and non-zerod pages at the head. 1076 */ 1077 if (m->flags & PG_ZERO) { 1078 TAILQ_INSERT_TAIL(&pq->pl, m, pageq); 1079 ++vm_page_zero_count; 1080 } else { 1081 TAILQ_INSERT_HEAD(&pq->pl, m, pageq); 1082 } 1083 mtx_unlock_spin(&vm_page_queue_free_mtx); 1084 vm_page_free_wakeup(); 1085} 1086 1087/* 1088 * vm_page_unmanage: 1089 * 1090 * Prevent PV management from being done on the page. The page is 1091 * removed from the paging queues as if it were wired, and as a 1092 * consequence of no longer being managed the pageout daemon will not 1093 * touch it (since there is no way to locate the pte mappings for the 1094 * page). madvise() calls that mess with the pmap will also no longer 1095 * operate on the page. 1096 * 1097 * Beyond that the page is still reasonably 'normal'. Freeing the page 1098 * will clear the flag. 1099 * 1100 * This routine is used by OBJT_PHYS objects - objects using unswappable 1101 * physical memory as backing store rather then swap-backed memory and 1102 * will eventually be extended to support 4MB unmanaged physical 1103 * mappings. 1104 */ 1105void 1106vm_page_unmanage(vm_page_t m) 1107{ 1108 1109 mtx_assert(&vm_page_queue_mtx, MA_OWNED); 1110 if ((m->flags & PG_UNMANAGED) == 0) { 1111 if (m->wire_count == 0) 1112 vm_pageq_remove(m); 1113 } 1114 vm_page_flag_set(m, PG_UNMANAGED); 1115} 1116 1117/* 1118 * vm_page_wire: 1119 * 1120 * Mark this page as wired down by yet 1121 * another map, removing it from paging queues 1122 * as necessary. 1123 * 1124 * The page queues must be locked. 1125 * This routine may not block. 1126 */ 1127void 1128vm_page_wire(vm_page_t m) 1129{ 1130 1131 /* 1132 * Only bump the wire statistics if the page is not already wired, 1133 * and only unqueue the page if it is on some queue (if it is unmanaged 1134 * it is already off the queues). 1135 */ 1136 mtx_assert(&vm_page_queue_mtx, MA_OWNED); 1137 if (m->flags & PG_FICTITIOUS) 1138 return; 1139 if (m->wire_count == 0) { 1140 if ((m->flags & PG_UNMANAGED) == 0) 1141 vm_pageq_remove(m); 1142 atomic_add_int(&cnt.v_wire_count, 1); 1143 } 1144 m->wire_count++; 1145 KASSERT(m->wire_count != 0, ("vm_page_wire: wire_count overflow m=%p", m)); 1146} 1147 1148/* 1149 * vm_page_unwire: 1150 * 1151 * Release one wiring of this page, potentially 1152 * enabling it to be paged again. 1153 * 1154 * Many pages placed on the inactive queue should actually go 1155 * into the cache, but it is difficult to figure out which. What 1156 * we do instead, if the inactive target is well met, is to put 1157 * clean pages at the head of the inactive queue instead of the tail. 1158 * This will cause them to be moved to the cache more quickly and 1159 * if not actively re-referenced, freed more quickly. If we just 1160 * stick these pages at the end of the inactive queue, heavy filesystem 1161 * meta-data accesses can cause an unnecessary paging load on memory bound 1162 * processes. This optimization causes one-time-use metadata to be 1163 * reused more quickly. 1164 * 1165 * BUT, if we are in a low-memory situation we have no choice but to 1166 * put clean pages on the cache queue. 1167 * 1168 * A number of routines use vm_page_unwire() to guarantee that the page 1169 * will go into either the inactive or active queues, and will NEVER 1170 * be placed in the cache - for example, just after dirtying a page. 1171 * dirty pages in the cache are not allowed. 1172 * 1173 * The page queues must be locked. 1174 * This routine may not block. 1175 */ 1176void 1177vm_page_unwire(vm_page_t m, int activate) 1178{ 1179 1180 mtx_assert(&vm_page_queue_mtx, MA_OWNED); 1181 if (m->flags & PG_FICTITIOUS) 1182 return; 1183 if (m->wire_count > 0) { 1184 m->wire_count--; 1185 if (m->wire_count == 0) { 1186 atomic_subtract_int(&cnt.v_wire_count, 1); 1187 if (m->flags & PG_UNMANAGED) { 1188 ; 1189 } else if (activate) 1190 vm_pageq_enqueue(PQ_ACTIVE, m); 1191 else { 1192 vm_page_flag_clear(m, PG_WINATCFLS); 1193 vm_pageq_enqueue(PQ_INACTIVE, m); 1194 } 1195 } 1196 } else { 1197 panic("vm_page_unwire: invalid wire count: %d", m->wire_count); 1198 } 1199} 1200 1201 1202/* 1203 * Move the specified page to the inactive queue. If the page has 1204 * any associated swap, the swap is deallocated. 1205 * 1206 * Normally athead is 0 resulting in LRU operation. athead is set 1207 * to 1 if we want this page to be 'as if it were placed in the cache', 1208 * except without unmapping it from the process address space. 1209 * 1210 * This routine may not block. 1211 */ 1212static __inline void 1213_vm_page_deactivate(vm_page_t m, int athead) 1214{ 1215 1216 mtx_assert(&vm_page_queue_mtx, MA_OWNED); 1217 1218 /* 1219 * Ignore if already inactive. 1220 */ 1221 if (m->queue == PQ_INACTIVE) 1222 return; 1223 if (m->wire_count == 0 && (m->flags & PG_UNMANAGED) == 0) { 1224 if ((m->queue - m->pc) == PQ_CACHE) 1225 cnt.v_reactivated++; 1226 vm_page_flag_clear(m, PG_WINATCFLS); 1227 vm_pageq_remove(m); 1228 if (athead) 1229 TAILQ_INSERT_HEAD(&vm_page_queues[PQ_INACTIVE].pl, m, pageq); 1230 else 1231 TAILQ_INSERT_TAIL(&vm_page_queues[PQ_INACTIVE].pl, m, pageq); 1232 m->queue = PQ_INACTIVE; 1233 vm_page_queues[PQ_INACTIVE].lcnt++; 1234 cnt.v_inactive_count++; 1235 } 1236} 1237 1238void 1239vm_page_deactivate(vm_page_t m) 1240{ 1241 _vm_page_deactivate(m, 0); 1242} 1243 1244/* 1245 * vm_page_try_to_cache: 1246 * 1247 * Returns 0 on failure, 1 on success 1248 */ 1249int 1250vm_page_try_to_cache(vm_page_t m) 1251{ 1252 1253 mtx_assert(&vm_page_queue_mtx, MA_OWNED); 1254 VM_OBJECT_LOCK_ASSERT(m->object, MA_OWNED); 1255 if (m->dirty || m->hold_count || m->busy || m->wire_count || 1256 (m->flags & (PG_BUSY|PG_UNMANAGED))) { 1257 return (0); 1258 } 1259 pmap_remove_all(m); 1260 if (m->dirty) 1261 return (0); 1262 vm_page_cache(m); 1263 return (1); 1264} 1265 1266/* 1267 * vm_page_try_to_free() 1268 * 1269 * Attempt to free the page. If we cannot free it, we do nothing. 1270 * 1 is returned on success, 0 on failure. 1271 */ 1272int 1273vm_page_try_to_free(vm_page_t m) 1274{ 1275 1276 mtx_assert(&vm_page_queue_mtx, MA_OWNED); 1277 if (m->object != NULL) 1278 VM_OBJECT_LOCK_ASSERT(m->object, MA_OWNED); 1279 if (m->dirty || m->hold_count || m->busy || m->wire_count || 1280 (m->flags & (PG_BUSY|PG_UNMANAGED))) { 1281 return (0); 1282 } 1283 pmap_remove_all(m); 1284 if (m->dirty) 1285 return (0); 1286 vm_page_free(m); 1287 return (1); 1288} 1289 1290/* 1291 * vm_page_cache 1292 * 1293 * Put the specified page onto the page cache queue (if appropriate). 1294 * 1295 * This routine may not block. 1296 */ 1297void 1298vm_page_cache(vm_page_t m) 1299{ 1300 1301 mtx_assert(&vm_page_queue_mtx, MA_OWNED); 1302 VM_OBJECT_LOCK_ASSERT(m->object, MA_OWNED); 1303 if ((m->flags & (PG_BUSY|PG_UNMANAGED)) || m->busy || 1304 m->hold_count || m->wire_count) { 1305 printf("vm_page_cache: attempting to cache busy page\n"); 1306 return; 1307 } 1308 if ((m->queue - m->pc) == PQ_CACHE) 1309 return; 1310 1311 /* 1312 * Remove all pmaps and indicate that the page is not 1313 * writeable or mapped. 1314 */ 1315 pmap_remove_all(m); 1316 if (m->dirty != 0) { 1317 panic("vm_page_cache: caching a dirty page, pindex: %ld", 1318 (long)m->pindex); 1319 } 1320 vm_pageq_remove_nowakeup(m); 1321 vm_pageq_enqueue(PQ_CACHE + m->pc, m); 1322 vm_page_free_wakeup(); 1323} 1324 1325/* 1326 * vm_page_dontneed 1327 * 1328 * Cache, deactivate, or do nothing as appropriate. This routine 1329 * is typically used by madvise() MADV_DONTNEED. 1330 * 1331 * Generally speaking we want to move the page into the cache so 1332 * it gets reused quickly. However, this can result in a silly syndrome 1333 * due to the page recycling too quickly. Small objects will not be 1334 * fully cached. On the otherhand, if we move the page to the inactive 1335 * queue we wind up with a problem whereby very large objects 1336 * unnecessarily blow away our inactive and cache queues. 1337 * 1338 * The solution is to move the pages based on a fixed weighting. We 1339 * either leave them alone, deactivate them, or move them to the cache, 1340 * where moving them to the cache has the highest weighting. 1341 * By forcing some pages into other queues we eventually force the 1342 * system to balance the queues, potentially recovering other unrelated 1343 * space from active. The idea is to not force this to happen too 1344 * often. 1345 */ 1346void 1347vm_page_dontneed(vm_page_t m) 1348{ 1349 static int dnweight; 1350 int dnw; 1351 int head; 1352 1353 mtx_assert(&vm_page_queue_mtx, MA_OWNED); 1354 dnw = ++dnweight; 1355 1356 /* 1357 * occassionally leave the page alone 1358 */ 1359 if ((dnw & 0x01F0) == 0 || 1360 m->queue == PQ_INACTIVE || 1361 m->queue - m->pc == PQ_CACHE 1362 ) { 1363 if (m->act_count >= ACT_INIT) 1364 --m->act_count; 1365 return; 1366 } 1367 1368 if (m->dirty == 0 && pmap_is_modified(m)) 1369 vm_page_dirty(m); 1370 1371 if (m->dirty || (dnw & 0x0070) == 0) { 1372 /* 1373 * Deactivate the page 3 times out of 32. 1374 */ 1375 head = 0; 1376 } else { 1377 /* 1378 * Cache the page 28 times out of every 32. Note that 1379 * the page is deactivated instead of cached, but placed 1380 * at the head of the queue instead of the tail. 1381 */ 1382 head = 1; 1383 } 1384 _vm_page_deactivate(m, head); 1385} 1386 1387/* 1388 * Grab a page, waiting until we are waken up due to the page 1389 * changing state. We keep on waiting, if the page continues 1390 * to be in the object. If the page doesn't exist, first allocate it 1391 * and then conditionally zero it. 1392 * 1393 * This routine may block. 1394 */ 1395vm_page_t 1396vm_page_grab(vm_object_t object, vm_pindex_t pindex, int allocflags) 1397{ 1398 vm_page_t m; 1399 1400 VM_OBJECT_LOCK_ASSERT(object, MA_OWNED); 1401retrylookup: 1402 if ((m = vm_page_lookup(object, pindex)) != NULL) { 1403 vm_page_lock_queues(); 1404 if (m->busy || (m->flags & PG_BUSY)) { 1405 vm_page_flag_set(m, PG_WANTED | PG_REFERENCED); 1406 VM_OBJECT_UNLOCK(object); 1407 msleep(m, &vm_page_queue_mtx, PDROP | PVM, "pgrbwt", 0); 1408 VM_OBJECT_LOCK(object); 1409 if ((allocflags & VM_ALLOC_RETRY) == 0) 1410 return (NULL); 1411 goto retrylookup; 1412 } else { 1413 if (allocflags & VM_ALLOC_WIRED) 1414 vm_page_wire(m); 1415 if ((allocflags & VM_ALLOC_NOBUSY) == 0) 1416 vm_page_busy(m); 1417 vm_page_unlock_queues(); 1418 return (m); 1419 } 1420 } 1421 m = vm_page_alloc(object, pindex, allocflags & ~VM_ALLOC_RETRY); 1422 if (m == NULL) { 1423 VM_OBJECT_UNLOCK(object); 1424 VM_WAIT; 1425 VM_OBJECT_LOCK(object); 1426 if ((allocflags & VM_ALLOC_RETRY) == 0) 1427 return (NULL); 1428 goto retrylookup; 1429 } 1430 if (allocflags & VM_ALLOC_ZERO && (m->flags & PG_ZERO) == 0) 1431 pmap_zero_page(m); 1432 return (m); 1433} 1434 1435/* 1436 * Mapping function for valid bits or for dirty bits in 1437 * a page. May not block. 1438 * 1439 * Inputs are required to range within a page. 1440 */ 1441__inline int 1442vm_page_bits(int base, int size) 1443{ 1444 int first_bit; 1445 int last_bit; 1446 1447 KASSERT( 1448 base + size <= PAGE_SIZE, 1449 ("vm_page_bits: illegal base/size %d/%d", base, size) 1450 ); 1451 1452 if (size == 0) /* handle degenerate case */ 1453 return (0); 1454 1455 first_bit = base >> DEV_BSHIFT; 1456 last_bit = (base + size - 1) >> DEV_BSHIFT; 1457 1458 return ((2 << last_bit) - (1 << first_bit)); 1459} 1460 1461/* 1462 * vm_page_set_validclean: 1463 * 1464 * Sets portions of a page valid and clean. The arguments are expected 1465 * to be DEV_BSIZE aligned but if they aren't the bitmap is inclusive 1466 * of any partial chunks touched by the range. The invalid portion of 1467 * such chunks will be zero'd. 1468 * 1469 * This routine may not block. 1470 * 1471 * (base + size) must be less then or equal to PAGE_SIZE. 1472 */ 1473void 1474vm_page_set_validclean(vm_page_t m, int base, int size) 1475{ 1476 int pagebits; 1477 int frag; 1478 int endoff; 1479 1480 mtx_assert(&vm_page_queue_mtx, MA_OWNED); 1481 VM_OBJECT_LOCK_ASSERT(m->object, MA_OWNED); 1482 if (size == 0) /* handle degenerate case */ 1483 return; 1484 1485 /* 1486 * If the base is not DEV_BSIZE aligned and the valid 1487 * bit is clear, we have to zero out a portion of the 1488 * first block. 1489 */ 1490 if ((frag = base & ~(DEV_BSIZE - 1)) != base && 1491 (m->valid & (1 << (base >> DEV_BSHIFT))) == 0) 1492 pmap_zero_page_area(m, frag, base - frag); 1493 1494 /* 1495 * If the ending offset is not DEV_BSIZE aligned and the 1496 * valid bit is clear, we have to zero out a portion of 1497 * the last block. 1498 */ 1499 endoff = base + size; 1500 if ((frag = endoff & ~(DEV_BSIZE - 1)) != endoff && 1501 (m->valid & (1 << (endoff >> DEV_BSHIFT))) == 0) 1502 pmap_zero_page_area(m, endoff, 1503 DEV_BSIZE - (endoff & (DEV_BSIZE - 1))); 1504 1505 /* 1506 * Set valid, clear dirty bits. If validating the entire 1507 * page we can safely clear the pmap modify bit. We also 1508 * use this opportunity to clear the PG_NOSYNC flag. If a process 1509 * takes a write fault on a MAP_NOSYNC memory area the flag will 1510 * be set again. 1511 * 1512 * We set valid bits inclusive of any overlap, but we can only 1513 * clear dirty bits for DEV_BSIZE chunks that are fully within 1514 * the range. 1515 */ 1516 pagebits = vm_page_bits(base, size); 1517 m->valid |= pagebits; 1518#if 0 /* NOT YET */ 1519 if ((frag = base & (DEV_BSIZE - 1)) != 0) { 1520 frag = DEV_BSIZE - frag; 1521 base += frag; 1522 size -= frag; 1523 if (size < 0) 1524 size = 0; 1525 } 1526 pagebits = vm_page_bits(base, size & (DEV_BSIZE - 1)); 1527#endif 1528 m->dirty &= ~pagebits; 1529 if (base == 0 && size == PAGE_SIZE) { 1530 pmap_clear_modify(m); 1531 vm_page_flag_clear(m, PG_NOSYNC); 1532 } 1533} 1534 1535void 1536vm_page_clear_dirty(vm_page_t m, int base, int size) 1537{ 1538 1539 mtx_assert(&vm_page_queue_mtx, MA_OWNED); 1540 m->dirty &= ~vm_page_bits(base, size); 1541} 1542 1543/* 1544 * vm_page_set_invalid: 1545 * 1546 * Invalidates DEV_BSIZE'd chunks within a page. Both the 1547 * valid and dirty bits for the effected areas are cleared. 1548 * 1549 * May not block. 1550 */ 1551void 1552vm_page_set_invalid(vm_page_t m, int base, int size) 1553{ 1554 int bits; 1555 1556 VM_OBJECT_LOCK_ASSERT(m->object, MA_OWNED); 1557 bits = vm_page_bits(base, size); 1558 mtx_assert(&vm_page_queue_mtx, MA_OWNED); 1559 m->valid &= ~bits; 1560 m->dirty &= ~bits; 1561 m->object->generation++; 1562} 1563 1564/* 1565 * vm_page_zero_invalid() 1566 * 1567 * The kernel assumes that the invalid portions of a page contain 1568 * garbage, but such pages can be mapped into memory by user code. 1569 * When this occurs, we must zero out the non-valid portions of the 1570 * page so user code sees what it expects. 1571 * 1572 * Pages are most often semi-valid when the end of a file is mapped 1573 * into memory and the file's size is not page aligned. 1574 */ 1575void 1576vm_page_zero_invalid(vm_page_t m, boolean_t setvalid) 1577{ 1578 int b; 1579 int i; 1580 1581 VM_OBJECT_LOCK_ASSERT(m->object, MA_OWNED); 1582 /* 1583 * Scan the valid bits looking for invalid sections that 1584 * must be zerod. Invalid sub-DEV_BSIZE'd areas ( where the 1585 * valid bit may be set ) have already been zerod by 1586 * vm_page_set_validclean(). 1587 */ 1588 for (b = i = 0; i <= PAGE_SIZE / DEV_BSIZE; ++i) { 1589 if (i == (PAGE_SIZE / DEV_BSIZE) || 1590 (m->valid & (1 << i)) 1591 ) { 1592 if (i > b) { 1593 pmap_zero_page_area(m, 1594 b << DEV_BSHIFT, (i - b) << DEV_BSHIFT); 1595 } 1596 b = i + 1; 1597 } 1598 } 1599 1600 /* 1601 * setvalid is TRUE when we can safely set the zero'd areas 1602 * as being valid. We can do this if there are no cache consistancy 1603 * issues. e.g. it is ok to do with UFS, but not ok to do with NFS. 1604 */ 1605 if (setvalid) 1606 m->valid = VM_PAGE_BITS_ALL; 1607} 1608 1609/* 1610 * vm_page_is_valid: 1611 * 1612 * Is (partial) page valid? Note that the case where size == 0 1613 * will return FALSE in the degenerate case where the page is 1614 * entirely invalid, and TRUE otherwise. 1615 * 1616 * May not block. 1617 */ 1618int 1619vm_page_is_valid(vm_page_t m, int base, int size) 1620{ 1621 int bits = vm_page_bits(base, size); 1622 1623 VM_OBJECT_LOCK_ASSERT(m->object, MA_OWNED); 1624 if (m->valid && ((m->valid & bits) == bits)) 1625 return 1; 1626 else 1627 return 0; 1628} 1629 1630/* 1631 * update dirty bits from pmap/mmu. May not block. 1632 */ 1633void 1634vm_page_test_dirty(vm_page_t m) 1635{ 1636 if ((m->dirty != VM_PAGE_BITS_ALL) && pmap_is_modified(m)) { 1637 vm_page_dirty(m); 1638 } 1639} 1640 1641int so_zerocp_fullpage = 0; 1642 1643void 1644vm_page_cowfault(vm_page_t m) 1645{ 1646 vm_page_t mnew; 1647 vm_object_t object; 1648 vm_pindex_t pindex; 1649 1650 object = m->object; 1651 pindex = m->pindex; 1652 1653 retry_alloc: 1654 vm_page_remove(m); 1655 mnew = vm_page_alloc(object, pindex, VM_ALLOC_NORMAL); 1656 if (mnew == NULL) { 1657 vm_page_insert(m, object, pindex); 1658 vm_page_unlock_queues(); 1659 VM_OBJECT_UNLOCK(object); 1660 VM_WAIT; 1661 VM_OBJECT_LOCK(object); 1662 vm_page_lock_queues(); 1663 goto retry_alloc; 1664 } 1665 1666 if (m->cow == 0) { 1667 /* 1668 * check to see if we raced with an xmit complete when 1669 * waiting to allocate a page. If so, put things back 1670 * the way they were 1671 */ 1672 vm_page_free(mnew); 1673 vm_page_insert(m, object, pindex); 1674 } else { /* clear COW & copy page */ 1675 if (!so_zerocp_fullpage) 1676 pmap_copy_page(m, mnew); 1677 mnew->valid = VM_PAGE_BITS_ALL; 1678 vm_page_dirty(mnew); 1679 vm_page_flag_clear(mnew, PG_BUSY); 1680 } 1681} 1682 1683void 1684vm_page_cowclear(vm_page_t m) 1685{ 1686 1687 mtx_assert(&vm_page_queue_mtx, MA_OWNED); 1688 if (m->cow) { 1689 m->cow--; 1690 /* 1691 * let vm_fault add back write permission lazily 1692 */ 1693 } 1694 /* 1695 * sf_buf_free() will free the page, so we needn't do it here 1696 */ 1697} 1698 1699void 1700vm_page_cowsetup(vm_page_t m) 1701{ 1702 1703 mtx_assert(&vm_page_queue_mtx, MA_OWNED); 1704 m->cow++; 1705 pmap_page_protect(m, VM_PROT_READ); 1706} 1707 1708#include "opt_ddb.h" 1709#ifdef DDB 1710#include <sys/kernel.h> 1711 1712#include <ddb/ddb.h> 1713 1714DB_SHOW_COMMAND(page, vm_page_print_page_info) 1715{ 1716 db_printf("cnt.v_free_count: %d\n", cnt.v_free_count); 1717 db_printf("cnt.v_cache_count: %d\n", cnt.v_cache_count); 1718 db_printf("cnt.v_inactive_count: %d\n", cnt.v_inactive_count); 1719 db_printf("cnt.v_active_count: %d\n", cnt.v_active_count); 1720 db_printf("cnt.v_wire_count: %d\n", cnt.v_wire_count); 1721 db_printf("cnt.v_free_reserved: %d\n", cnt.v_free_reserved); 1722 db_printf("cnt.v_free_min: %d\n", cnt.v_free_min); 1723 db_printf("cnt.v_free_target: %d\n", cnt.v_free_target); 1724 db_printf("cnt.v_cache_min: %d\n", cnt.v_cache_min); 1725 db_printf("cnt.v_inactive_target: %d\n", cnt.v_inactive_target); 1726} 1727 1728DB_SHOW_COMMAND(pageq, vm_page_print_pageq_info) 1729{ 1730 int i; 1731 db_printf("PQ_FREE:"); 1732 for (i = 0; i < PQ_L2_SIZE; i++) { 1733 db_printf(" %d", vm_page_queues[PQ_FREE + i].lcnt); 1734 } 1735 db_printf("\n"); 1736 1737 db_printf("PQ_CACHE:"); 1738 for (i = 0; i < PQ_L2_SIZE; i++) { 1739 db_printf(" %d", vm_page_queues[PQ_CACHE + i].lcnt); 1740 } 1741 db_printf("\n"); 1742 1743 db_printf("PQ_ACTIVE: %d, PQ_INACTIVE: %d\n", 1744 vm_page_queues[PQ_ACTIVE].lcnt, 1745 vm_page_queues[PQ_INACTIVE].lcnt); 1746} 1747#endif /* DDB */
| 234 235 /* 236 * Compute the number of pages of memory that will be available for 237 * use (taking into account the overhead of a page structure per 238 * page). 239 */ 240 first_page = phys_avail[0] / PAGE_SIZE; 241 page_range = phys_avail[(nblocks - 1) * 2 + 1] / PAGE_SIZE - first_page; 242 npages = (total - (page_range * sizeof(struct vm_page)) - 243 (end - new_end)) / PAGE_SIZE; 244 end = new_end; 245 246 /* 247 * Reserve an unmapped guard page to trap access to vm_page_array[-1]. 248 */ 249 vaddr += PAGE_SIZE; 250 251 /* 252 * Initialize the mem entry structures now, and put them in the free 253 * queue. 254 */ 255 new_end = trunc_page(end - page_range * sizeof(struct vm_page)); 256 mapped = pmap_map(&vaddr, new_end, end, 257 VM_PROT_READ | VM_PROT_WRITE); 258 vm_page_array = (vm_page_t) mapped; 259 phys_avail[biggestone + 1] = new_end; 260 261 /* 262 * Clear all of the page structures 263 */ 264 bzero((caddr_t) vm_page_array, page_range * sizeof(struct vm_page)); 265 vm_page_array_size = page_range; 266 267 /* 268 * Construct the free queue(s) in descending order (by physical 269 * address) so that the first 16MB of physical memory is allocated 270 * last rather than first. On large-memory machines, this avoids 271 * the exhaustion of low physical memory before isa_dma_init has run. 272 */ 273 cnt.v_page_count = 0; 274 cnt.v_free_count = 0; 275 for (i = 0; phys_avail[i + 1] && npages > 0; i += 2) { 276 pa = phys_avail[i]; 277 last_pa = phys_avail[i + 1]; 278 while (pa < last_pa && npages-- > 0) { 279 vm_pageq_add_new_page(pa); 280 pa += PAGE_SIZE; 281 } 282 } 283 return (vaddr); 284} 285 286void 287vm_page_flag_set(vm_page_t m, unsigned short bits) 288{ 289 290 mtx_assert(&vm_page_queue_mtx, MA_OWNED); 291 m->flags |= bits; 292} 293 294void 295vm_page_flag_clear(vm_page_t m, unsigned short bits) 296{ 297 298 mtx_assert(&vm_page_queue_mtx, MA_OWNED); 299 m->flags &= ~bits; 300} 301 302void 303vm_page_busy(vm_page_t m) 304{ 305 306 VM_OBJECT_LOCK_ASSERT(m->object, MA_OWNED); 307 KASSERT((m->flags & PG_BUSY) == 0, 308 ("vm_page_busy: page already busy!!!")); 309 vm_page_flag_set(m, PG_BUSY); 310} 311 312/* 313 * vm_page_flash: 314 * 315 * wakeup anyone waiting for the page. 316 */ 317void 318vm_page_flash(vm_page_t m) 319{ 320 321 VM_OBJECT_LOCK_ASSERT(m->object, MA_OWNED); 322 if (m->flags & PG_WANTED) { 323 vm_page_flag_clear(m, PG_WANTED); 324 wakeup(m); 325 } 326} 327 328/* 329 * vm_page_wakeup: 330 * 331 * clear the PG_BUSY flag and wakeup anyone waiting for the 332 * page. 333 * 334 */ 335void 336vm_page_wakeup(vm_page_t m) 337{ 338 339 VM_OBJECT_LOCK_ASSERT(m->object, MA_OWNED); 340 KASSERT(m->flags & PG_BUSY, ("vm_page_wakeup: page not busy!!!")); 341 vm_page_flag_clear(m, PG_BUSY); 342 vm_page_flash(m); 343} 344 345void 346vm_page_io_start(vm_page_t m) 347{ 348 349 VM_OBJECT_LOCK_ASSERT(m->object, MA_OWNED); 350 m->busy++; 351} 352 353void 354vm_page_io_finish(vm_page_t m) 355{ 356 357 VM_OBJECT_LOCK_ASSERT(m->object, MA_OWNED); 358 mtx_assert(&vm_page_queue_mtx, MA_OWNED); 359 m->busy--; 360 if (m->busy == 0) 361 vm_page_flash(m); 362} 363 364/* 365 * Keep page from being freed by the page daemon 366 * much of the same effect as wiring, except much lower 367 * overhead and should be used only for *very* temporary 368 * holding ("wiring"). 369 */ 370void 371vm_page_hold(vm_page_t mem) 372{ 373 374 mtx_assert(&vm_page_queue_mtx, MA_OWNED); 375 mem->hold_count++; 376} 377 378void 379vm_page_unhold(vm_page_t mem) 380{ 381 382 mtx_assert(&vm_page_queue_mtx, MA_OWNED); 383 --mem->hold_count; 384 KASSERT(mem->hold_count >= 0, ("vm_page_unhold: hold count < 0!!!")); 385 if (mem->hold_count == 0 && mem->queue == PQ_HOLD) 386 vm_page_free_toq(mem); 387} 388 389/* 390 * vm_page_free: 391 * 392 * Free a page 393 * 394 * The clearing of PG_ZERO is a temporary safety until the code can be 395 * reviewed to determine that PG_ZERO is being properly cleared on 396 * write faults or maps. PG_ZERO was previously cleared in 397 * vm_page_alloc(). 398 */ 399void 400vm_page_free(vm_page_t m) 401{ 402 vm_page_flag_clear(m, PG_ZERO); 403 vm_page_free_toq(m); 404 vm_page_zero_idle_wakeup(); 405} 406 407/* 408 * vm_page_free_zero: 409 * 410 * Free a page to the zerod-pages queue 411 */ 412void 413vm_page_free_zero(vm_page_t m) 414{ 415 vm_page_flag_set(m, PG_ZERO); 416 vm_page_free_toq(m); 417} 418 419/* 420 * vm_page_sleep_if_busy: 421 * 422 * Sleep and release the page queues lock if PG_BUSY is set or, 423 * if also_m_busy is TRUE, busy is non-zero. Returns TRUE if the 424 * thread slept and the page queues lock was released. 425 * Otherwise, retains the page queues lock and returns FALSE. 426 */ 427int 428vm_page_sleep_if_busy(vm_page_t m, int also_m_busy, const char *msg) 429{ 430 vm_object_t object; 431 432 mtx_assert(&vm_page_queue_mtx, MA_OWNED); 433 VM_OBJECT_LOCK_ASSERT(m->object, MA_OWNED); 434 if ((m->flags & PG_BUSY) || (also_m_busy && m->busy)) { 435 vm_page_flag_set(m, PG_WANTED | PG_REFERENCED); 436 /* 437 * It's possible that while we sleep, the page will get 438 * unbusied and freed. If we are holding the object 439 * lock, we will assume we hold a reference to the object 440 * such that even if m->object changes, we can re-lock 441 * it. 442 */ 443 object = m->object; 444 VM_OBJECT_UNLOCK(object); 445 msleep(m, &vm_page_queue_mtx, PDROP | PVM, msg, 0); 446 VM_OBJECT_LOCK(object); 447 return (TRUE); 448 } 449 return (FALSE); 450} 451 452/* 453 * vm_page_dirty: 454 * 455 * make page all dirty 456 */ 457void 458vm_page_dirty(vm_page_t m) 459{ 460 KASSERT(m->queue - m->pc != PQ_CACHE, 461 ("vm_page_dirty: page in cache!")); 462 KASSERT(m->queue - m->pc != PQ_FREE, 463 ("vm_page_dirty: page is free!")); 464 m->dirty = VM_PAGE_BITS_ALL; 465} 466 467/* 468 * vm_page_splay: 469 * 470 * Implements Sleator and Tarjan's top-down splay algorithm. Returns 471 * the vm_page containing the given pindex. If, however, that 472 * pindex is not found in the vm_object, returns a vm_page that is 473 * adjacent to the pindex, coming before or after it. 474 */ 475vm_page_t 476vm_page_splay(vm_pindex_t pindex, vm_page_t root) 477{ 478 struct vm_page dummy; 479 vm_page_t lefttreemax, righttreemin, y; 480 481 if (root == NULL) 482 return (root); 483 lefttreemax = righttreemin = &dummy; 484 for (;; root = y) { 485 if (pindex < root->pindex) { 486 if ((y = root->left) == NULL) 487 break; 488 if (pindex < y->pindex) { 489 /* Rotate right. */ 490 root->left = y->right; 491 y->right = root; 492 root = y; 493 if ((y = root->left) == NULL) 494 break; 495 } 496 /* Link into the new root's right tree. */ 497 righttreemin->left = root; 498 righttreemin = root; 499 } else if (pindex > root->pindex) { 500 if ((y = root->right) == NULL) 501 break; 502 if (pindex > y->pindex) { 503 /* Rotate left. */ 504 root->right = y->left; 505 y->left = root; 506 root = y; 507 if ((y = root->right) == NULL) 508 break; 509 } 510 /* Link into the new root's left tree. */ 511 lefttreemax->right = root; 512 lefttreemax = root; 513 } else 514 break; 515 } 516 /* Assemble the new root. */ 517 lefttreemax->right = root->left; 518 righttreemin->left = root->right; 519 root->left = dummy.right; 520 root->right = dummy.left; 521 return (root); 522} 523 524/* 525 * vm_page_insert: [ internal use only ] 526 * 527 * Inserts the given mem entry into the object and object list. 528 * 529 * The pagetables are not updated but will presumably fault the page 530 * in if necessary, or if a kernel page the caller will at some point 531 * enter the page into the kernel's pmap. We are not allowed to block 532 * here so we *can't* do this anyway. 533 * 534 * The object and page must be locked. 535 * This routine may not block. 536 */ 537void 538vm_page_insert(vm_page_t m, vm_object_t object, vm_pindex_t pindex) 539{ 540 vm_page_t root; 541 542 VM_OBJECT_LOCK_ASSERT(object, MA_OWNED); 543 if (m->object != NULL) 544 panic("vm_page_insert: page already inserted"); 545 546 /* 547 * Record the object/offset pair in this page 548 */ 549 m->object = object; 550 m->pindex = pindex; 551 552 /* 553 * Now link into the object's ordered list of backed pages. 554 */ 555 root = object->root; 556 if (root == NULL) { 557 m->left = NULL; 558 m->right = NULL; 559 TAILQ_INSERT_TAIL(&object->memq, m, listq); 560 } else { 561 root = vm_page_splay(pindex, root); 562 if (pindex < root->pindex) { 563 m->left = root->left; 564 m->right = root; 565 root->left = NULL; 566 TAILQ_INSERT_BEFORE(root, m, listq); 567 } else if (pindex == root->pindex) 568 panic("vm_page_insert: offset already allocated"); 569 else { 570 m->right = root->right; 571 m->left = root; 572 root->right = NULL; 573 TAILQ_INSERT_AFTER(&object->memq, root, m, listq); 574 } 575 } 576 object->root = m; 577 object->generation++; 578 579 /* 580 * show that the object has one more resident page. 581 */ 582 object->resident_page_count++; 583 /* 584 * Hold the vnode until the last page is released. 585 */ 586 if (object->resident_page_count == 1 && object->type == OBJT_VNODE) 587 vhold((struct vnode *)object->handle); 588 589 /* 590 * Since we are inserting a new and possibly dirty page, 591 * update the object's OBJ_WRITEABLE and OBJ_MIGHTBEDIRTY flags. 592 */ 593 if (m->flags & PG_WRITEABLE) 594 vm_object_set_writeable_dirty(object); 595} 596 597/* 598 * vm_page_remove: 599 * NOTE: used by device pager as well -wfj 600 * 601 * Removes the given mem entry from the object/offset-page 602 * table and the object page list, but do not invalidate/terminate 603 * the backing store. 604 * 605 * The object and page must be locked. 606 * The underlying pmap entry (if any) is NOT removed here. 607 * This routine may not block. 608 */ 609void 610vm_page_remove(vm_page_t m) 611{ 612 vm_object_t object; 613 vm_page_t root; 614 615 mtx_assert(&vm_page_queue_mtx, MA_OWNED); 616 if ((object = m->object) == NULL) 617 return; 618 VM_OBJECT_LOCK_ASSERT(object, MA_OWNED); 619 if (m->flags & PG_BUSY) { 620 vm_page_flag_clear(m, PG_BUSY); 621 vm_page_flash(m); 622 } 623 624 /* 625 * Now remove from the object's list of backed pages. 626 */ 627 if (m != object->root) 628 vm_page_splay(m->pindex, object->root); 629 if (m->left == NULL) 630 root = m->right; 631 else { 632 root = vm_page_splay(m->pindex, m->left); 633 root->right = m->right; 634 } 635 object->root = root; 636 TAILQ_REMOVE(&object->memq, m, listq); 637 638 /* 639 * And show that the object has one fewer resident page. 640 */ 641 object->resident_page_count--; 642 object->generation++; 643 /* 644 * The vnode may now be recycled. 645 */ 646 if (object->resident_page_count == 0 && object->type == OBJT_VNODE) 647 vdrop((struct vnode *)object->handle); 648 649 m->object = NULL; 650} 651 652/* 653 * vm_page_lookup: 654 * 655 * Returns the page associated with the object/offset 656 * pair specified; if none is found, NULL is returned. 657 * 658 * The object must be locked. 659 * This routine may not block. 660 * This is a critical path routine 661 */ 662vm_page_t 663vm_page_lookup(vm_object_t object, vm_pindex_t pindex) 664{ 665 vm_page_t m; 666 667 VM_OBJECT_LOCK_ASSERT(object, MA_OWNED); 668 if ((m = object->root) != NULL && m->pindex != pindex) { 669 m = vm_page_splay(pindex, m); 670 if ((object->root = m)->pindex != pindex) 671 m = NULL; 672 } 673 return (m); 674} 675 676/* 677 * vm_page_rename: 678 * 679 * Move the given memory entry from its 680 * current object to the specified target object/offset. 681 * 682 * The object must be locked. 683 * This routine may not block. 684 * 685 * Note: swap associated with the page must be invalidated by the move. We 686 * have to do this for several reasons: (1) we aren't freeing the 687 * page, (2) we are dirtying the page, (3) the VM system is probably 688 * moving the page from object A to B, and will then later move 689 * the backing store from A to B and we can't have a conflict. 690 * 691 * Note: we *always* dirty the page. It is necessary both for the 692 * fact that we moved it, and because we may be invalidating 693 * swap. If the page is on the cache, we have to deactivate it 694 * or vm_page_dirty() will panic. Dirty pages are not allowed 695 * on the cache. 696 */ 697void 698vm_page_rename(vm_page_t m, vm_object_t new_object, vm_pindex_t new_pindex) 699{ 700 701 vm_page_remove(m); 702 vm_page_insert(m, new_object, new_pindex); 703 if (m->queue - m->pc == PQ_CACHE) 704 vm_page_deactivate(m); 705 vm_page_dirty(m); 706} 707 708/* 709 * vm_page_select_cache: 710 * 711 * Move a page of the given color from the cache queue to the free 712 * queue. As pages might be found, but are not applicable, they are 713 * deactivated. 714 * 715 * This routine may not block. 716 */ 717vm_page_t 718vm_page_select_cache(int color) 719{ 720 vm_object_t object; 721 vm_page_t m; 722 boolean_t was_trylocked; 723 724 mtx_assert(&vm_page_queue_mtx, MA_OWNED); 725 while ((m = vm_pageq_find(PQ_CACHE, color, FALSE)) != NULL) { 726 KASSERT(m->dirty == 0, ("Found dirty cache page %p", m)); 727 KASSERT(!pmap_page_is_mapped(m), 728 ("Found mapped cache page %p", m)); 729 KASSERT((m->flags & PG_UNMANAGED) == 0, 730 ("Found unmanaged cache page %p", m)); 731 KASSERT(m->wire_count == 0, ("Found wired cache page %p", m)); 732 if (m->hold_count == 0 && (object = m->object, 733 (was_trylocked = VM_OBJECT_TRYLOCK(object)) || 734 VM_OBJECT_LOCKED(object))) { 735 KASSERT((m->flags & PG_BUSY) == 0 && m->busy == 0, 736 ("Found busy cache page %p", m)); 737 vm_page_free(m); 738 if (was_trylocked) 739 VM_OBJECT_UNLOCK(object); 740 break; 741 } 742 vm_page_deactivate(m); 743 } 744 return (m); 745} 746 747/* 748 * vm_page_alloc: 749 * 750 * Allocate and return a memory cell associated 751 * with this VM object/offset pair. 752 * 753 * page_req classes: 754 * VM_ALLOC_NORMAL normal process request 755 * VM_ALLOC_SYSTEM system *really* needs a page 756 * VM_ALLOC_INTERRUPT interrupt time request 757 * VM_ALLOC_ZERO zero page 758 * 759 * This routine may not block. 760 * 761 * Additional special handling is required when called from an 762 * interrupt (VM_ALLOC_INTERRUPT). We are not allowed to mess with 763 * the page cache in this case. 764 */ 765vm_page_t 766vm_page_alloc(vm_object_t object, vm_pindex_t pindex, int req) 767{ 768 vm_page_t m = NULL; 769 int color, flags, page_req; 770 771 page_req = req & VM_ALLOC_CLASS_MASK; 772 KASSERT(curthread->td_intr_nesting_level == 0 || 773 page_req == VM_ALLOC_INTERRUPT, 774 ("vm_page_alloc(NORMAL|SYSTEM) in interrupt context")); 775 776 if ((req & VM_ALLOC_NOOBJ) == 0) { 777 KASSERT(object != NULL, 778 ("vm_page_alloc: NULL object.")); 779 VM_OBJECT_LOCK_ASSERT(object, MA_OWNED); 780 color = (pindex + object->pg_color) & PQ_L2_MASK; 781 } else 782 color = pindex & PQ_L2_MASK; 783 784 /* 785 * The pager is allowed to eat deeper into the free page list. 786 */ 787 if ((curproc == pageproc) && (page_req != VM_ALLOC_INTERRUPT)) { 788 page_req = VM_ALLOC_SYSTEM; 789 }; 790 791loop: 792 mtx_lock_spin(&vm_page_queue_free_mtx); 793 if (cnt.v_free_count > cnt.v_free_reserved || 794 (page_req == VM_ALLOC_SYSTEM && 795 cnt.v_cache_count == 0 && 796 cnt.v_free_count > cnt.v_interrupt_free_min) || 797 (page_req == VM_ALLOC_INTERRUPT && cnt.v_free_count > 0)) { 798 /* 799 * Allocate from the free queue if the number of free pages 800 * exceeds the minimum for the request class. 801 */ 802 m = vm_pageq_find(PQ_FREE, color, (req & VM_ALLOC_ZERO) != 0); 803 } else if (page_req != VM_ALLOC_INTERRUPT) { 804 mtx_unlock_spin(&vm_page_queue_free_mtx); 805 /* 806 * Allocatable from cache (non-interrupt only). On success, 807 * we must free the page and try again, thus ensuring that 808 * cnt.v_*_free_min counters are replenished. 809 */ 810 vm_page_lock_queues(); 811 if ((m = vm_page_select_cache(color)) == NULL) { 812#if defined(DIAGNOSTIC) 813 if (cnt.v_cache_count > 0) 814 printf("vm_page_alloc(NORMAL): missing pages on cache queue: %d\n", cnt.v_cache_count); 815#endif 816 vm_page_unlock_queues(); 817 atomic_add_int(&vm_pageout_deficit, 1); 818 pagedaemon_wakeup(); 819 return (NULL); 820 } 821 vm_page_unlock_queues(); 822 goto loop; 823 } else { 824 /* 825 * Not allocatable from cache from interrupt, give up. 826 */ 827 mtx_unlock_spin(&vm_page_queue_free_mtx); 828 atomic_add_int(&vm_pageout_deficit, 1); 829 pagedaemon_wakeup(); 830 return (NULL); 831 } 832 833 /* 834 * At this point we had better have found a good page. 835 */ 836 837 KASSERT( 838 m != NULL, 839 ("vm_page_alloc(): missing page on free queue") 840 ); 841 842 /* 843 * Remove from free queue 844 */ 845 vm_pageq_remove_nowakeup(m); 846 847 /* 848 * Initialize structure. Only the PG_ZERO flag is inherited. 849 */ 850 flags = PG_BUSY; 851 if (m->flags & PG_ZERO) { 852 vm_page_zero_count--; 853 if (req & VM_ALLOC_ZERO) 854 flags = PG_ZERO | PG_BUSY; 855 } 856 if (req & (VM_ALLOC_NOBUSY | VM_ALLOC_NOOBJ)) 857 flags &= ~PG_BUSY; 858 m->flags = flags; 859 if (req & VM_ALLOC_WIRED) { 860 atomic_add_int(&cnt.v_wire_count, 1); 861 m->wire_count = 1; 862 } else 863 m->wire_count = 0; 864 m->hold_count = 0; 865 m->act_count = 0; 866 m->busy = 0; 867 m->valid = 0; 868 KASSERT(m->dirty == 0, ("vm_page_alloc: free/cache page %p was dirty", m)); 869 mtx_unlock_spin(&vm_page_queue_free_mtx); 870 871 if ((req & VM_ALLOC_NOOBJ) == 0) 872 vm_page_insert(m, object, pindex); 873 else 874 m->pindex = pindex; 875 876 /* 877 * Don't wakeup too often - wakeup the pageout daemon when 878 * we would be nearly out of memory. 879 */ 880 if (vm_paging_needed()) 881 pagedaemon_wakeup(); 882 883 return (m); 884} 885 886/* 887 * vm_wait: (also see VM_WAIT macro) 888 * 889 * Block until free pages are available for allocation 890 * - Called in various places before memory allocations. 891 */ 892void 893vm_wait(void) 894{ 895 896 vm_page_lock_queues(); 897 if (curproc == pageproc) { 898 vm_pageout_pages_needed = 1; 899 msleep(&vm_pageout_pages_needed, &vm_page_queue_mtx, 900 PDROP | PSWP, "VMWait", 0); 901 } else { 902 if (!vm_pages_needed) { 903 vm_pages_needed = 1; 904 wakeup(&vm_pages_needed); 905 } 906 msleep(&cnt.v_free_count, &vm_page_queue_mtx, PDROP | PVM, 907 "vmwait", 0); 908 } 909} 910 911/* 912 * vm_waitpfault: (also see VM_WAITPFAULT macro) 913 * 914 * Block until free pages are available for allocation 915 * - Called only in vm_fault so that processes page faulting 916 * can be easily tracked. 917 * - Sleeps at a lower priority than vm_wait() so that vm_wait()ing 918 * processes will be able to grab memory first. Do not change 919 * this balance without careful testing first. 920 */ 921void 922vm_waitpfault(void) 923{ 924 925 vm_page_lock_queues(); 926 if (!vm_pages_needed) { 927 vm_pages_needed = 1; 928 wakeup(&vm_pages_needed); 929 } 930 msleep(&cnt.v_free_count, &vm_page_queue_mtx, PDROP | PUSER, 931 "pfault", 0); 932} 933 934/* 935 * vm_page_activate: 936 * 937 * Put the specified page on the active list (if appropriate). 938 * Ensure that act_count is at least ACT_INIT but do not otherwise 939 * mess with it. 940 * 941 * The page queues must be locked. 942 * This routine may not block. 943 */ 944void 945vm_page_activate(vm_page_t m) 946{ 947 948 mtx_assert(&vm_page_queue_mtx, MA_OWNED); 949 if (m->queue != PQ_ACTIVE) { 950 if ((m->queue - m->pc) == PQ_CACHE) 951 cnt.v_reactivated++; 952 vm_pageq_remove(m); 953 if (m->wire_count == 0 && (m->flags & PG_UNMANAGED) == 0) { 954 if (m->act_count < ACT_INIT) 955 m->act_count = ACT_INIT; 956 vm_pageq_enqueue(PQ_ACTIVE, m); 957 } 958 } else { 959 if (m->act_count < ACT_INIT) 960 m->act_count = ACT_INIT; 961 } 962} 963 964/* 965 * vm_page_free_wakeup: 966 * 967 * Helper routine for vm_page_free_toq() and vm_page_cache(). This 968 * routine is called when a page has been added to the cache or free 969 * queues. 970 * 971 * The page queues must be locked. 972 * This routine may not block. 973 */ 974static __inline void 975vm_page_free_wakeup(void) 976{ 977 978 mtx_assert(&vm_page_queue_mtx, MA_OWNED); 979 /* 980 * if pageout daemon needs pages, then tell it that there are 981 * some free. 982 */ 983 if (vm_pageout_pages_needed && 984 cnt.v_cache_count + cnt.v_free_count >= cnt.v_pageout_free_min) { 985 wakeup(&vm_pageout_pages_needed); 986 vm_pageout_pages_needed = 0; 987 } 988 /* 989 * wakeup processes that are waiting on memory if we hit a 990 * high water mark. And wakeup scheduler process if we have 991 * lots of memory. this process will swapin processes. 992 */ 993 if (vm_pages_needed && !vm_page_count_min()) { 994 vm_pages_needed = 0; 995 wakeup(&cnt.v_free_count); 996 } 997} 998 999/* 1000 * vm_page_free_toq: 1001 * 1002 * Returns the given page to the PQ_FREE list, 1003 * disassociating it with any VM object. 1004 * 1005 * Object and page must be locked prior to entry. 1006 * This routine may not block. 1007 */ 1008 1009void 1010vm_page_free_toq(vm_page_t m) 1011{ 1012 struct vpgqueues *pq; 1013 1014 mtx_assert(&vm_page_queue_mtx, MA_OWNED); 1015 cnt.v_tfree++; 1016 1017 if (m->busy || ((m->queue - m->pc) == PQ_FREE)) { 1018 printf( 1019 "vm_page_free: pindex(%lu), busy(%d), PG_BUSY(%d), hold(%d)\n", 1020 (u_long)m->pindex, m->busy, (m->flags & PG_BUSY) ? 1 : 0, 1021 m->hold_count); 1022 if ((m->queue - m->pc) == PQ_FREE) 1023 panic("vm_page_free: freeing free page"); 1024 else 1025 panic("vm_page_free: freeing busy page"); 1026 } 1027 1028 /* 1029 * unqueue, then remove page. Note that we cannot destroy 1030 * the page here because we do not want to call the pager's 1031 * callback routine until after we've put the page on the 1032 * appropriate free queue. 1033 */ 1034 vm_pageq_remove_nowakeup(m); 1035 vm_page_remove(m); 1036 1037 /* 1038 * If fictitious remove object association and 1039 * return, otherwise delay object association removal. 1040 */ 1041 if ((m->flags & PG_FICTITIOUS) != 0) { 1042 return; 1043 } 1044 1045 m->valid = 0; 1046 vm_page_undirty(m); 1047 1048 if (m->wire_count != 0) { 1049 if (m->wire_count > 1) { 1050 panic("vm_page_free: invalid wire count (%d), pindex: 0x%lx", 1051 m->wire_count, (long)m->pindex); 1052 } 1053 panic("vm_page_free: freeing wired page"); 1054 } 1055 1056 /* 1057 * Clear the UNMANAGED flag when freeing an unmanaged page. 1058 */ 1059 if (m->flags & PG_UNMANAGED) { 1060 m->flags &= ~PG_UNMANAGED; 1061 } 1062 1063 if (m->hold_count != 0) { 1064 m->flags &= ~PG_ZERO; 1065 m->queue = PQ_HOLD; 1066 } else 1067 m->queue = PQ_FREE + m->pc; 1068 pq = &vm_page_queues[m->queue]; 1069 mtx_lock_spin(&vm_page_queue_free_mtx); 1070 pq->lcnt++; 1071 ++(*pq->cnt); 1072 1073 /* 1074 * Put zero'd pages on the end ( where we look for zero'd pages 1075 * first ) and non-zerod pages at the head. 1076 */ 1077 if (m->flags & PG_ZERO) { 1078 TAILQ_INSERT_TAIL(&pq->pl, m, pageq); 1079 ++vm_page_zero_count; 1080 } else { 1081 TAILQ_INSERT_HEAD(&pq->pl, m, pageq); 1082 } 1083 mtx_unlock_spin(&vm_page_queue_free_mtx); 1084 vm_page_free_wakeup(); 1085} 1086 1087/* 1088 * vm_page_unmanage: 1089 * 1090 * Prevent PV management from being done on the page. The page is 1091 * removed from the paging queues as if it were wired, and as a 1092 * consequence of no longer being managed the pageout daemon will not 1093 * touch it (since there is no way to locate the pte mappings for the 1094 * page). madvise() calls that mess with the pmap will also no longer 1095 * operate on the page. 1096 * 1097 * Beyond that the page is still reasonably 'normal'. Freeing the page 1098 * will clear the flag. 1099 * 1100 * This routine is used by OBJT_PHYS objects - objects using unswappable 1101 * physical memory as backing store rather then swap-backed memory and 1102 * will eventually be extended to support 4MB unmanaged physical 1103 * mappings. 1104 */ 1105void 1106vm_page_unmanage(vm_page_t m) 1107{ 1108 1109 mtx_assert(&vm_page_queue_mtx, MA_OWNED); 1110 if ((m->flags & PG_UNMANAGED) == 0) { 1111 if (m->wire_count == 0) 1112 vm_pageq_remove(m); 1113 } 1114 vm_page_flag_set(m, PG_UNMANAGED); 1115} 1116 1117/* 1118 * vm_page_wire: 1119 * 1120 * Mark this page as wired down by yet 1121 * another map, removing it from paging queues 1122 * as necessary. 1123 * 1124 * The page queues must be locked. 1125 * This routine may not block. 1126 */ 1127void 1128vm_page_wire(vm_page_t m) 1129{ 1130 1131 /* 1132 * Only bump the wire statistics if the page is not already wired, 1133 * and only unqueue the page if it is on some queue (if it is unmanaged 1134 * it is already off the queues). 1135 */ 1136 mtx_assert(&vm_page_queue_mtx, MA_OWNED); 1137 if (m->flags & PG_FICTITIOUS) 1138 return; 1139 if (m->wire_count == 0) { 1140 if ((m->flags & PG_UNMANAGED) == 0) 1141 vm_pageq_remove(m); 1142 atomic_add_int(&cnt.v_wire_count, 1); 1143 } 1144 m->wire_count++; 1145 KASSERT(m->wire_count != 0, ("vm_page_wire: wire_count overflow m=%p", m)); 1146} 1147 1148/* 1149 * vm_page_unwire: 1150 * 1151 * Release one wiring of this page, potentially 1152 * enabling it to be paged again. 1153 * 1154 * Many pages placed on the inactive queue should actually go 1155 * into the cache, but it is difficult to figure out which. What 1156 * we do instead, if the inactive target is well met, is to put 1157 * clean pages at the head of the inactive queue instead of the tail. 1158 * This will cause them to be moved to the cache more quickly and 1159 * if not actively re-referenced, freed more quickly. If we just 1160 * stick these pages at the end of the inactive queue, heavy filesystem 1161 * meta-data accesses can cause an unnecessary paging load on memory bound 1162 * processes. This optimization causes one-time-use metadata to be 1163 * reused more quickly. 1164 * 1165 * BUT, if we are in a low-memory situation we have no choice but to 1166 * put clean pages on the cache queue. 1167 * 1168 * A number of routines use vm_page_unwire() to guarantee that the page 1169 * will go into either the inactive or active queues, and will NEVER 1170 * be placed in the cache - for example, just after dirtying a page. 1171 * dirty pages in the cache are not allowed. 1172 * 1173 * The page queues must be locked. 1174 * This routine may not block. 1175 */ 1176void 1177vm_page_unwire(vm_page_t m, int activate) 1178{ 1179 1180 mtx_assert(&vm_page_queue_mtx, MA_OWNED); 1181 if (m->flags & PG_FICTITIOUS) 1182 return; 1183 if (m->wire_count > 0) { 1184 m->wire_count--; 1185 if (m->wire_count == 0) { 1186 atomic_subtract_int(&cnt.v_wire_count, 1); 1187 if (m->flags & PG_UNMANAGED) { 1188 ; 1189 } else if (activate) 1190 vm_pageq_enqueue(PQ_ACTIVE, m); 1191 else { 1192 vm_page_flag_clear(m, PG_WINATCFLS); 1193 vm_pageq_enqueue(PQ_INACTIVE, m); 1194 } 1195 } 1196 } else { 1197 panic("vm_page_unwire: invalid wire count: %d", m->wire_count); 1198 } 1199} 1200 1201 1202/* 1203 * Move the specified page to the inactive queue. If the page has 1204 * any associated swap, the swap is deallocated. 1205 * 1206 * Normally athead is 0 resulting in LRU operation. athead is set 1207 * to 1 if we want this page to be 'as if it were placed in the cache', 1208 * except without unmapping it from the process address space. 1209 * 1210 * This routine may not block. 1211 */ 1212static __inline void 1213_vm_page_deactivate(vm_page_t m, int athead) 1214{ 1215 1216 mtx_assert(&vm_page_queue_mtx, MA_OWNED); 1217 1218 /* 1219 * Ignore if already inactive. 1220 */ 1221 if (m->queue == PQ_INACTIVE) 1222 return; 1223 if (m->wire_count == 0 && (m->flags & PG_UNMANAGED) == 0) { 1224 if ((m->queue - m->pc) == PQ_CACHE) 1225 cnt.v_reactivated++; 1226 vm_page_flag_clear(m, PG_WINATCFLS); 1227 vm_pageq_remove(m); 1228 if (athead) 1229 TAILQ_INSERT_HEAD(&vm_page_queues[PQ_INACTIVE].pl, m, pageq); 1230 else 1231 TAILQ_INSERT_TAIL(&vm_page_queues[PQ_INACTIVE].pl, m, pageq); 1232 m->queue = PQ_INACTIVE; 1233 vm_page_queues[PQ_INACTIVE].lcnt++; 1234 cnt.v_inactive_count++; 1235 } 1236} 1237 1238void 1239vm_page_deactivate(vm_page_t m) 1240{ 1241 _vm_page_deactivate(m, 0); 1242} 1243 1244/* 1245 * vm_page_try_to_cache: 1246 * 1247 * Returns 0 on failure, 1 on success 1248 */ 1249int 1250vm_page_try_to_cache(vm_page_t m) 1251{ 1252 1253 mtx_assert(&vm_page_queue_mtx, MA_OWNED); 1254 VM_OBJECT_LOCK_ASSERT(m->object, MA_OWNED); 1255 if (m->dirty || m->hold_count || m->busy || m->wire_count || 1256 (m->flags & (PG_BUSY|PG_UNMANAGED))) { 1257 return (0); 1258 } 1259 pmap_remove_all(m); 1260 if (m->dirty) 1261 return (0); 1262 vm_page_cache(m); 1263 return (1); 1264} 1265 1266/* 1267 * vm_page_try_to_free() 1268 * 1269 * Attempt to free the page. If we cannot free it, we do nothing. 1270 * 1 is returned on success, 0 on failure. 1271 */ 1272int 1273vm_page_try_to_free(vm_page_t m) 1274{ 1275 1276 mtx_assert(&vm_page_queue_mtx, MA_OWNED); 1277 if (m->object != NULL) 1278 VM_OBJECT_LOCK_ASSERT(m->object, MA_OWNED); 1279 if (m->dirty || m->hold_count || m->busy || m->wire_count || 1280 (m->flags & (PG_BUSY|PG_UNMANAGED))) { 1281 return (0); 1282 } 1283 pmap_remove_all(m); 1284 if (m->dirty) 1285 return (0); 1286 vm_page_free(m); 1287 return (1); 1288} 1289 1290/* 1291 * vm_page_cache 1292 * 1293 * Put the specified page onto the page cache queue (if appropriate). 1294 * 1295 * This routine may not block. 1296 */ 1297void 1298vm_page_cache(vm_page_t m) 1299{ 1300 1301 mtx_assert(&vm_page_queue_mtx, MA_OWNED); 1302 VM_OBJECT_LOCK_ASSERT(m->object, MA_OWNED); 1303 if ((m->flags & (PG_BUSY|PG_UNMANAGED)) || m->busy || 1304 m->hold_count || m->wire_count) { 1305 printf("vm_page_cache: attempting to cache busy page\n"); 1306 return; 1307 } 1308 if ((m->queue - m->pc) == PQ_CACHE) 1309 return; 1310 1311 /* 1312 * Remove all pmaps and indicate that the page is not 1313 * writeable or mapped. 1314 */ 1315 pmap_remove_all(m); 1316 if (m->dirty != 0) { 1317 panic("vm_page_cache: caching a dirty page, pindex: %ld", 1318 (long)m->pindex); 1319 } 1320 vm_pageq_remove_nowakeup(m); 1321 vm_pageq_enqueue(PQ_CACHE + m->pc, m); 1322 vm_page_free_wakeup(); 1323} 1324 1325/* 1326 * vm_page_dontneed 1327 * 1328 * Cache, deactivate, or do nothing as appropriate. This routine 1329 * is typically used by madvise() MADV_DONTNEED. 1330 * 1331 * Generally speaking we want to move the page into the cache so 1332 * it gets reused quickly. However, this can result in a silly syndrome 1333 * due to the page recycling too quickly. Small objects will not be 1334 * fully cached. On the otherhand, if we move the page to the inactive 1335 * queue we wind up with a problem whereby very large objects 1336 * unnecessarily blow away our inactive and cache queues. 1337 * 1338 * The solution is to move the pages based on a fixed weighting. We 1339 * either leave them alone, deactivate them, or move them to the cache, 1340 * where moving them to the cache has the highest weighting. 1341 * By forcing some pages into other queues we eventually force the 1342 * system to balance the queues, potentially recovering other unrelated 1343 * space from active. The idea is to not force this to happen too 1344 * often. 1345 */ 1346void 1347vm_page_dontneed(vm_page_t m) 1348{ 1349 static int dnweight; 1350 int dnw; 1351 int head; 1352 1353 mtx_assert(&vm_page_queue_mtx, MA_OWNED); 1354 dnw = ++dnweight; 1355 1356 /* 1357 * occassionally leave the page alone 1358 */ 1359 if ((dnw & 0x01F0) == 0 || 1360 m->queue == PQ_INACTIVE || 1361 m->queue - m->pc == PQ_CACHE 1362 ) { 1363 if (m->act_count >= ACT_INIT) 1364 --m->act_count; 1365 return; 1366 } 1367 1368 if (m->dirty == 0 && pmap_is_modified(m)) 1369 vm_page_dirty(m); 1370 1371 if (m->dirty || (dnw & 0x0070) == 0) { 1372 /* 1373 * Deactivate the page 3 times out of 32. 1374 */ 1375 head = 0; 1376 } else { 1377 /* 1378 * Cache the page 28 times out of every 32. Note that 1379 * the page is deactivated instead of cached, but placed 1380 * at the head of the queue instead of the tail. 1381 */ 1382 head = 1; 1383 } 1384 _vm_page_deactivate(m, head); 1385} 1386 1387/* 1388 * Grab a page, waiting until we are waken up due to the page 1389 * changing state. We keep on waiting, if the page continues 1390 * to be in the object. If the page doesn't exist, first allocate it 1391 * and then conditionally zero it. 1392 * 1393 * This routine may block. 1394 */ 1395vm_page_t 1396vm_page_grab(vm_object_t object, vm_pindex_t pindex, int allocflags) 1397{ 1398 vm_page_t m; 1399 1400 VM_OBJECT_LOCK_ASSERT(object, MA_OWNED); 1401retrylookup: 1402 if ((m = vm_page_lookup(object, pindex)) != NULL) { 1403 vm_page_lock_queues(); 1404 if (m->busy || (m->flags & PG_BUSY)) { 1405 vm_page_flag_set(m, PG_WANTED | PG_REFERENCED); 1406 VM_OBJECT_UNLOCK(object); 1407 msleep(m, &vm_page_queue_mtx, PDROP | PVM, "pgrbwt", 0); 1408 VM_OBJECT_LOCK(object); 1409 if ((allocflags & VM_ALLOC_RETRY) == 0) 1410 return (NULL); 1411 goto retrylookup; 1412 } else { 1413 if (allocflags & VM_ALLOC_WIRED) 1414 vm_page_wire(m); 1415 if ((allocflags & VM_ALLOC_NOBUSY) == 0) 1416 vm_page_busy(m); 1417 vm_page_unlock_queues(); 1418 return (m); 1419 } 1420 } 1421 m = vm_page_alloc(object, pindex, allocflags & ~VM_ALLOC_RETRY); 1422 if (m == NULL) { 1423 VM_OBJECT_UNLOCK(object); 1424 VM_WAIT; 1425 VM_OBJECT_LOCK(object); 1426 if ((allocflags & VM_ALLOC_RETRY) == 0) 1427 return (NULL); 1428 goto retrylookup; 1429 } 1430 if (allocflags & VM_ALLOC_ZERO && (m->flags & PG_ZERO) == 0) 1431 pmap_zero_page(m); 1432 return (m); 1433} 1434 1435/* 1436 * Mapping function for valid bits or for dirty bits in 1437 * a page. May not block. 1438 * 1439 * Inputs are required to range within a page. 1440 */ 1441__inline int 1442vm_page_bits(int base, int size) 1443{ 1444 int first_bit; 1445 int last_bit; 1446 1447 KASSERT( 1448 base + size <= PAGE_SIZE, 1449 ("vm_page_bits: illegal base/size %d/%d", base, size) 1450 ); 1451 1452 if (size == 0) /* handle degenerate case */ 1453 return (0); 1454 1455 first_bit = base >> DEV_BSHIFT; 1456 last_bit = (base + size - 1) >> DEV_BSHIFT; 1457 1458 return ((2 << last_bit) - (1 << first_bit)); 1459} 1460 1461/* 1462 * vm_page_set_validclean: 1463 * 1464 * Sets portions of a page valid and clean. The arguments are expected 1465 * to be DEV_BSIZE aligned but if they aren't the bitmap is inclusive 1466 * of any partial chunks touched by the range. The invalid portion of 1467 * such chunks will be zero'd. 1468 * 1469 * This routine may not block. 1470 * 1471 * (base + size) must be less then or equal to PAGE_SIZE. 1472 */ 1473void 1474vm_page_set_validclean(vm_page_t m, int base, int size) 1475{ 1476 int pagebits; 1477 int frag; 1478 int endoff; 1479 1480 mtx_assert(&vm_page_queue_mtx, MA_OWNED); 1481 VM_OBJECT_LOCK_ASSERT(m->object, MA_OWNED); 1482 if (size == 0) /* handle degenerate case */ 1483 return; 1484 1485 /* 1486 * If the base is not DEV_BSIZE aligned and the valid 1487 * bit is clear, we have to zero out a portion of the 1488 * first block. 1489 */ 1490 if ((frag = base & ~(DEV_BSIZE - 1)) != base && 1491 (m->valid & (1 << (base >> DEV_BSHIFT))) == 0) 1492 pmap_zero_page_area(m, frag, base - frag); 1493 1494 /* 1495 * If the ending offset is not DEV_BSIZE aligned and the 1496 * valid bit is clear, we have to zero out a portion of 1497 * the last block. 1498 */ 1499 endoff = base + size; 1500 if ((frag = endoff & ~(DEV_BSIZE - 1)) != endoff && 1501 (m->valid & (1 << (endoff >> DEV_BSHIFT))) == 0) 1502 pmap_zero_page_area(m, endoff, 1503 DEV_BSIZE - (endoff & (DEV_BSIZE - 1))); 1504 1505 /* 1506 * Set valid, clear dirty bits. If validating the entire 1507 * page we can safely clear the pmap modify bit. We also 1508 * use this opportunity to clear the PG_NOSYNC flag. If a process 1509 * takes a write fault on a MAP_NOSYNC memory area the flag will 1510 * be set again. 1511 * 1512 * We set valid bits inclusive of any overlap, but we can only 1513 * clear dirty bits for DEV_BSIZE chunks that are fully within 1514 * the range. 1515 */ 1516 pagebits = vm_page_bits(base, size); 1517 m->valid |= pagebits; 1518#if 0 /* NOT YET */ 1519 if ((frag = base & (DEV_BSIZE - 1)) != 0) { 1520 frag = DEV_BSIZE - frag; 1521 base += frag; 1522 size -= frag; 1523 if (size < 0) 1524 size = 0; 1525 } 1526 pagebits = vm_page_bits(base, size & (DEV_BSIZE - 1)); 1527#endif 1528 m->dirty &= ~pagebits; 1529 if (base == 0 && size == PAGE_SIZE) { 1530 pmap_clear_modify(m); 1531 vm_page_flag_clear(m, PG_NOSYNC); 1532 } 1533} 1534 1535void 1536vm_page_clear_dirty(vm_page_t m, int base, int size) 1537{ 1538 1539 mtx_assert(&vm_page_queue_mtx, MA_OWNED); 1540 m->dirty &= ~vm_page_bits(base, size); 1541} 1542 1543/* 1544 * vm_page_set_invalid: 1545 * 1546 * Invalidates DEV_BSIZE'd chunks within a page. Both the 1547 * valid and dirty bits for the effected areas are cleared. 1548 * 1549 * May not block. 1550 */ 1551void 1552vm_page_set_invalid(vm_page_t m, int base, int size) 1553{ 1554 int bits; 1555 1556 VM_OBJECT_LOCK_ASSERT(m->object, MA_OWNED); 1557 bits = vm_page_bits(base, size); 1558 mtx_assert(&vm_page_queue_mtx, MA_OWNED); 1559 m->valid &= ~bits; 1560 m->dirty &= ~bits; 1561 m->object->generation++; 1562} 1563 1564/* 1565 * vm_page_zero_invalid() 1566 * 1567 * The kernel assumes that the invalid portions of a page contain 1568 * garbage, but such pages can be mapped into memory by user code. 1569 * When this occurs, we must zero out the non-valid portions of the 1570 * page so user code sees what it expects. 1571 * 1572 * Pages are most often semi-valid when the end of a file is mapped 1573 * into memory and the file's size is not page aligned. 1574 */ 1575void 1576vm_page_zero_invalid(vm_page_t m, boolean_t setvalid) 1577{ 1578 int b; 1579 int i; 1580 1581 VM_OBJECT_LOCK_ASSERT(m->object, MA_OWNED); 1582 /* 1583 * Scan the valid bits looking for invalid sections that 1584 * must be zerod. Invalid sub-DEV_BSIZE'd areas ( where the 1585 * valid bit may be set ) have already been zerod by 1586 * vm_page_set_validclean(). 1587 */ 1588 for (b = i = 0; i <= PAGE_SIZE / DEV_BSIZE; ++i) { 1589 if (i == (PAGE_SIZE / DEV_BSIZE) || 1590 (m->valid & (1 << i)) 1591 ) { 1592 if (i > b) { 1593 pmap_zero_page_area(m, 1594 b << DEV_BSHIFT, (i - b) << DEV_BSHIFT); 1595 } 1596 b = i + 1; 1597 } 1598 } 1599 1600 /* 1601 * setvalid is TRUE when we can safely set the zero'd areas 1602 * as being valid. We can do this if there are no cache consistancy 1603 * issues. e.g. it is ok to do with UFS, but not ok to do with NFS. 1604 */ 1605 if (setvalid) 1606 m->valid = VM_PAGE_BITS_ALL; 1607} 1608 1609/* 1610 * vm_page_is_valid: 1611 * 1612 * Is (partial) page valid? Note that the case where size == 0 1613 * will return FALSE in the degenerate case where the page is 1614 * entirely invalid, and TRUE otherwise. 1615 * 1616 * May not block. 1617 */ 1618int 1619vm_page_is_valid(vm_page_t m, int base, int size) 1620{ 1621 int bits = vm_page_bits(base, size); 1622 1623 VM_OBJECT_LOCK_ASSERT(m->object, MA_OWNED); 1624 if (m->valid && ((m->valid & bits) == bits)) 1625 return 1; 1626 else 1627 return 0; 1628} 1629 1630/* 1631 * update dirty bits from pmap/mmu. May not block. 1632 */ 1633void 1634vm_page_test_dirty(vm_page_t m) 1635{ 1636 if ((m->dirty != VM_PAGE_BITS_ALL) && pmap_is_modified(m)) { 1637 vm_page_dirty(m); 1638 } 1639} 1640 1641int so_zerocp_fullpage = 0; 1642 1643void 1644vm_page_cowfault(vm_page_t m) 1645{ 1646 vm_page_t mnew; 1647 vm_object_t object; 1648 vm_pindex_t pindex; 1649 1650 object = m->object; 1651 pindex = m->pindex; 1652 1653 retry_alloc: 1654 vm_page_remove(m); 1655 mnew = vm_page_alloc(object, pindex, VM_ALLOC_NORMAL); 1656 if (mnew == NULL) { 1657 vm_page_insert(m, object, pindex); 1658 vm_page_unlock_queues(); 1659 VM_OBJECT_UNLOCK(object); 1660 VM_WAIT; 1661 VM_OBJECT_LOCK(object); 1662 vm_page_lock_queues(); 1663 goto retry_alloc; 1664 } 1665 1666 if (m->cow == 0) { 1667 /* 1668 * check to see if we raced with an xmit complete when 1669 * waiting to allocate a page. If so, put things back 1670 * the way they were 1671 */ 1672 vm_page_free(mnew); 1673 vm_page_insert(m, object, pindex); 1674 } else { /* clear COW & copy page */ 1675 if (!so_zerocp_fullpage) 1676 pmap_copy_page(m, mnew); 1677 mnew->valid = VM_PAGE_BITS_ALL; 1678 vm_page_dirty(mnew); 1679 vm_page_flag_clear(mnew, PG_BUSY); 1680 } 1681} 1682 1683void 1684vm_page_cowclear(vm_page_t m) 1685{ 1686 1687 mtx_assert(&vm_page_queue_mtx, MA_OWNED); 1688 if (m->cow) { 1689 m->cow--; 1690 /* 1691 * let vm_fault add back write permission lazily 1692 */ 1693 } 1694 /* 1695 * sf_buf_free() will free the page, so we needn't do it here 1696 */ 1697} 1698 1699void 1700vm_page_cowsetup(vm_page_t m) 1701{ 1702 1703 mtx_assert(&vm_page_queue_mtx, MA_OWNED); 1704 m->cow++; 1705 pmap_page_protect(m, VM_PROT_READ); 1706} 1707 1708#include "opt_ddb.h" 1709#ifdef DDB 1710#include <sys/kernel.h> 1711 1712#include <ddb/ddb.h> 1713 1714DB_SHOW_COMMAND(page, vm_page_print_page_info) 1715{ 1716 db_printf("cnt.v_free_count: %d\n", cnt.v_free_count); 1717 db_printf("cnt.v_cache_count: %d\n", cnt.v_cache_count); 1718 db_printf("cnt.v_inactive_count: %d\n", cnt.v_inactive_count); 1719 db_printf("cnt.v_active_count: %d\n", cnt.v_active_count); 1720 db_printf("cnt.v_wire_count: %d\n", cnt.v_wire_count); 1721 db_printf("cnt.v_free_reserved: %d\n", cnt.v_free_reserved); 1722 db_printf("cnt.v_free_min: %d\n", cnt.v_free_min); 1723 db_printf("cnt.v_free_target: %d\n", cnt.v_free_target); 1724 db_printf("cnt.v_cache_min: %d\n", cnt.v_cache_min); 1725 db_printf("cnt.v_inactive_target: %d\n", cnt.v_inactive_target); 1726} 1727 1728DB_SHOW_COMMAND(pageq, vm_page_print_pageq_info) 1729{ 1730 int i; 1731 db_printf("PQ_FREE:"); 1732 for (i = 0; i < PQ_L2_SIZE; i++) { 1733 db_printf(" %d", vm_page_queues[PQ_FREE + i].lcnt); 1734 } 1735 db_printf("\n"); 1736 1737 db_printf("PQ_CACHE:"); 1738 for (i = 0; i < PQ_L2_SIZE; i++) { 1739 db_printf(" %d", vm_page_queues[PQ_CACHE + i].lcnt); 1740 } 1741 db_printf("\n"); 1742 1743 db_printf("PQ_ACTIVE: %d, PQ_INACTIVE: %d\n", 1744 vm_page_queues[PQ_ACTIVE].lcnt, 1745 vm_page_queues[PQ_INACTIVE].lcnt); 1746} 1747#endif /* DDB */
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