1 /* 2 * Copyright (c) 1991 Regents of the University of California. 3 * All rights reserved. 4 * 5 * This code is derived from software contributed to Berkeley by 6 * The Mach Operating System project at Carnegie-Mellon University. 7 * 8 * Redistribution and use in source and binary forms, with or without 9 * modification, are permitted provided that the following conditions 10 * are met: 11 * 1. Redistributions of source code must retain the above copyright 12 * notice, this list of conditions and the following disclaimer. 13 * 2. Redistributions in binary form must reproduce the above copyright 14 * notice, this list of conditions and the following disclaimer in the 15 * documentation and/or other materials provided with the distribution. 16 * 3. All advertising materials mentioning features or use of this software 17 * must display the following acknowledgement: 18 * This product includes software developed by the University of 19 * California, Berkeley and its contributors. 20 * 4. Neither the name of the University nor the names of its contributors 21 * may be used to endorse or promote products derived from this software 22 * without specific prior written permission. 23 * 24 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 25 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 26 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 27 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 28 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 29 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 30 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 31 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 32 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 33 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 34 * SUCH DAMAGE. 35 * 36 * from: @(#)vm_page.c 7.4 (Berkeley) 5/7/91 37 * $FreeBSD$ 38 */ 39 40 /* 41 * Copyright (c) 1987, 1990 Carnegie-Mellon University. 42 * All rights reserved. 43 * 44 * Authors: Avadis Tevanian, Jr., Michael Wayne Young 45 * 46 * Permission to use, copy, modify and distribute this software and 47 * its documentation is hereby granted, provided that both the copyright 48 * notice and this permission notice appear in all copies of the 49 * software, derivative works or modified versions, and any portions 50 * thereof, and that both notices appear in supporting documentation. 51 * 52 * CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS" 53 * CONDITION. CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND 54 * FOR ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE. 55 * 56 * Carnegie Mellon requests users of this software to return to 57 * 58 * Software Distribution Coordinator or Software.Distribution@CS.CMU.EDU 59 * School of Computer Science 60 * Carnegie Mellon University 61 * Pittsburgh PA 15213-3890 62 * 63 * any improvements or extensions that they make and grant Carnegie the 64 * rights to redistribute these changes. 65 */ 66 67 /* 68 * Resident memory management module. 69 */ 70 71 #include <sys/param.h> 72 #include <sys/systm.h> 73 #include <sys/malloc.h> 74 #include <sys/proc.h> 75 #include <sys/vmmeter.h> 76 #include <sys/vnode.h> 77 78 #include <vm/vm.h> 79 #include <vm/vm_param.h> 80 #include <sys/lock.h> 81 #include <vm/vm_kern.h> 82 #include <vm/vm_object.h> 83 #include <vm/vm_page.h> 84 #include <vm/vm_pageout.h> 85 #include <vm/vm_pager.h> 86 #include <vm/vm_extern.h> 87 88 static void vm_page_queue_init __P((void)); 89 static vm_page_t vm_page_select_cache __P((vm_object_t, vm_pindex_t)); 90 91 /* 92 * Associated with page of user-allocatable memory is a 93 * page structure. 94 */ 95 96 static struct vm_page **vm_page_buckets; /* Array of buckets */ 97 static int vm_page_bucket_count; /* How big is array? */ 98 static int vm_page_hash_mask; /* Mask for hash function */ 99 static volatile int vm_page_bucket_generation; 100 101 struct vpgqueues vm_page_queues[PQ_COUNT]; 102 103 static void 104 vm_page_queue_init(void) { 105 int i; 106 107 for(i=0;i<PQ_L2_SIZE;i++) { 108 vm_page_queues[PQ_FREE+i].cnt = &cnt.v_free_count; 109 } 110 vm_page_queues[PQ_INACTIVE].cnt = &cnt.v_inactive_count; 111 112 vm_page_queues[PQ_ACTIVE].cnt = &cnt.v_active_count; 113 for(i=0;i<PQ_L2_SIZE;i++) { 114 vm_page_queues[PQ_CACHE+i].cnt = &cnt.v_cache_count; 115 } 116 for(i=0;i<PQ_COUNT;i++) { 117 TAILQ_INIT(&vm_page_queues[i].pl); 118 } 119 } 120 121 vm_page_t vm_page_array = 0; 122 int vm_page_array_size = 0; 123 long first_page = 0; 124 int vm_page_zero_count = 0; 125 126 static __inline int vm_page_hash __P((vm_object_t object, vm_pindex_t pindex)); 127 static void vm_page_free_wakeup __P((void)); 128 129 /* 130 * vm_set_page_size: 131 * 132 * Sets the page size, perhaps based upon the memory 133 * size. Must be called before any use of page-size 134 * dependent functions. 135 */ 136 void 137 vm_set_page_size() 138 { 139 if (cnt.v_page_size == 0) 140 cnt.v_page_size = PAGE_SIZE; 141 if (((cnt.v_page_size - 1) & cnt.v_page_size) != 0) 142 panic("vm_set_page_size: page size not a power of two"); 143 } 144 145 /* 146 * vm_add_new_page: 147 * 148 * Add a new page to the freelist for use by the system. 149 * Must be called at splhigh(). 150 */ 151 vm_page_t 152 vm_add_new_page(pa) 153 vm_offset_t pa; 154 { 155 vm_page_t m; 156 157 ++cnt.v_page_count; 158 ++cnt.v_free_count; 159 m = PHYS_TO_VM_PAGE(pa); 160 m->phys_addr = pa; 161 m->flags = 0; 162 m->pc = (pa >> PAGE_SHIFT) & PQ_L2_MASK; 163 m->queue = m->pc + PQ_FREE; 164 TAILQ_INSERT_HEAD(&vm_page_queues[m->queue].pl, m, pageq); 165 vm_page_queues[m->queue].lcnt++; 166 return (m); 167 } 168 169 /* 170 * vm_page_startup: 171 * 172 * Initializes the resident memory module. 173 * 174 * Allocates memory for the page cells, and 175 * for the object/offset-to-page hash table headers. 176 * Each page cell is initialized and placed on the free list. 177 */ 178 179 vm_offset_t 180 vm_page_startup(starta, enda, vaddr) 181 register vm_offset_t starta; 182 vm_offset_t enda; 183 register vm_offset_t vaddr; 184 { 185 register vm_offset_t mapped; 186 register struct vm_page **bucket; 187 vm_size_t npages, page_range; 188 register vm_offset_t new_start; 189 int i; 190 vm_offset_t pa; 191 int nblocks; 192 vm_offset_t first_managed_page; 193 194 /* the biggest memory array is the second group of pages */ 195 vm_offset_t start; 196 vm_offset_t biggestone, biggestsize; 197 198 vm_offset_t total; 199 200 total = 0; 201 biggestsize = 0; 202 biggestone = 0; 203 nblocks = 0; 204 vaddr = round_page(vaddr); 205 206 for (i = 0; phys_avail[i + 1]; i += 2) { 207 phys_avail[i] = round_page(phys_avail[i]); 208 phys_avail[i + 1] = trunc_page(phys_avail[i + 1]); 209 } 210 211 for (i = 0; phys_avail[i + 1]; i += 2) { 212 int size = phys_avail[i + 1] - phys_avail[i]; 213 214 if (size > biggestsize) { 215 biggestone = i; 216 biggestsize = size; 217 } 218 ++nblocks; 219 total += size; 220 } 221 222 start = phys_avail[biggestone]; 223 224 /* 225 * Initialize the queue headers for the free queue, the active queue 226 * and the inactive queue. 227 */ 228 229 vm_page_queue_init(); 230 231 /* 232 * Allocate (and initialize) the hash table buckets. 233 * 234 * The number of buckets MUST BE a power of 2, and the actual value is 235 * the next power of 2 greater than the number of physical pages in 236 * the system. 237 * 238 * We make the hash table approximately 2x the number of pages to 239 * reduce the chain length. This is about the same size using the 240 * singly-linked list as the 1x hash table we were using before 241 * using TAILQ but the chain length will be smaller. 242 * 243 * Note: This computation can be tweaked if desired. 244 */ 245 vm_page_buckets = (struct vm_page **)vaddr; 246 bucket = vm_page_buckets; 247 if (vm_page_bucket_count == 0) { 248 vm_page_bucket_count = 1; 249 while (vm_page_bucket_count < atop(total)) 250 vm_page_bucket_count <<= 1; 251 } 252 vm_page_bucket_count <<= 1; 253 vm_page_hash_mask = vm_page_bucket_count - 1; 254 255 /* 256 * Validate these addresses. 257 */ 258 259 new_start = start + vm_page_bucket_count * sizeof(struct vm_page *); 260 new_start = round_page(new_start); 261 mapped = round_page(vaddr); 262 vaddr = pmap_map(mapped, start, new_start, 263 VM_PROT_READ | VM_PROT_WRITE); 264 start = new_start; 265 vaddr = round_page(vaddr); 266 bzero((caddr_t) mapped, vaddr - mapped); 267 268 for (i = 0; i < vm_page_bucket_count; i++) { 269 *bucket = NULL; 270 bucket++; 271 } 272 273 /* 274 * Compute the number of pages of memory that will be available for 275 * use (taking into account the overhead of a page structure per 276 * page). 277 */ 278 279 first_page = phys_avail[0] / PAGE_SIZE; 280 281 page_range = phys_avail[(nblocks - 1) * 2 + 1] / PAGE_SIZE - first_page; 282 npages = (total - (page_range * sizeof(struct vm_page)) - 283 (start - phys_avail[biggestone])) / PAGE_SIZE; 284 285 /* 286 * Initialize the mem entry structures now, and put them in the free 287 * queue. 288 */ 289 vm_page_array = (vm_page_t) vaddr; 290 mapped = vaddr; 291 292 /* 293 * Validate these addresses. 294 */ 295 new_start = round_page(start + page_range * sizeof(struct vm_page)); 296 mapped = pmap_map(mapped, start, new_start, 297 VM_PROT_READ | VM_PROT_WRITE); 298 start = new_start; 299 300 first_managed_page = start / PAGE_SIZE; 301 302 /* 303 * Clear all of the page structures 304 */ 305 bzero((caddr_t) vm_page_array, page_range * sizeof(struct vm_page)); 306 vm_page_array_size = page_range; 307 308 /* 309 * Construct the free queue(s) in descending order (by physical 310 * address) so that the first 16MB of physical memory is allocated 311 * last rather than first. On large-memory machines, this avoids 312 * the exhaustion of low physical memory before isa_dmainit has run. 313 */ 314 cnt.v_page_count = 0; 315 cnt.v_free_count = 0; 316 for (i = 0; phys_avail[i + 1] && npages > 0; i += 2) { 317 if (i == biggestone) 318 pa = ptoa(first_managed_page); 319 else 320 pa = phys_avail[i]; 321 while (pa < phys_avail[i + 1] && npages-- > 0) { 322 vm_add_new_page(pa); 323 pa += PAGE_SIZE; 324 } 325 } 326 return (mapped); 327 } 328 329 /* 330 * vm_page_hash: 331 * 332 * Distributes the object/offset key pair among hash buckets. 333 * 334 * NOTE: This macro depends on vm_page_bucket_count being a power of 2. 335 * This routine may not block. 336 * 337 * We try to randomize the hash based on the object to spread the pages 338 * out in the hash table without it costing us too much. 339 */ 340 static __inline int 341 vm_page_hash(object, pindex) 342 vm_object_t object; 343 vm_pindex_t pindex; 344 { 345 int i = ((uintptr_t)object + pindex) ^ object->hash_rand; 346 347 return(i & vm_page_hash_mask); 348 } 349 350 /* 351 * vm_page_insert: [ internal use only ] 352 * 353 * Inserts the given mem entry into the object and object list. 354 * 355 * The pagetables are not updated but will presumably fault the page 356 * in if necessary, or if a kernel page the caller will at some point 357 * enter the page into the kernel's pmap. We are not allowed to block 358 * here so we *can't* do this anyway. 359 * 360 * The object and page must be locked, and must be splhigh. 361 * This routine may not block. 362 */ 363 364 void 365 vm_page_insert(m, object, pindex) 366 register vm_page_t m; 367 register vm_object_t object; 368 register vm_pindex_t pindex; 369 { 370 register struct vm_page **bucket; 371 372 if (m->object != NULL) 373 panic("vm_page_insert: already inserted"); 374 375 /* 376 * Record the object/offset pair in this page 377 */ 378 379 m->object = object; 380 m->pindex = pindex; 381 382 /* 383 * Insert it into the object_object/offset hash table 384 */ 385 386 bucket = &vm_page_buckets[vm_page_hash(object, pindex)]; 387 m->hnext = *bucket; 388 *bucket = m; 389 vm_page_bucket_generation++; 390 391 /* 392 * Now link into the object's list of backed pages. 393 */ 394 395 TAILQ_INSERT_TAIL(&object->memq, m, listq); 396 object->generation++; 397 398 /* 399 * show that the object has one more resident page. 400 */ 401 402 object->resident_page_count++; 403 404 /* 405 * Since we are inserting a new and possibly dirty page, 406 * update the object's OBJ_WRITEABLE and OBJ_MIGHTBEDIRTY flags. 407 */ 408 if (m->flags & PG_WRITEABLE) 409 vm_object_set_flag(object, OBJ_WRITEABLE|OBJ_MIGHTBEDIRTY); 410 } 411 412 /* 413 * vm_page_remove: 414 * NOTE: used by device pager as well -wfj 415 * 416 * Removes the given mem entry from the object/offset-page 417 * table and the object page list, but do not invalidate/terminate 418 * the backing store. 419 * 420 * The object and page must be locked, and at splhigh. 421 * The underlying pmap entry (if any) is NOT removed here. 422 * This routine may not block. 423 */ 424 425 void 426 vm_page_remove(m) 427 vm_page_t m; 428 { 429 vm_object_t object; 430 431 if (m->object == NULL) 432 return; 433 434 if ((m->flags & PG_BUSY) == 0) { 435 panic("vm_page_remove: page not busy"); 436 } 437 438 /* 439 * Basically destroy the page. 440 */ 441 442 vm_page_wakeup(m); 443 444 object = m->object; 445 446 /* 447 * Remove from the object_object/offset hash table. The object 448 * must be on the hash queue, we will panic if it isn't 449 * 450 * Note: we must NULL-out m->hnext to prevent loops in detached 451 * buffers with vm_page_lookup(). 452 */ 453 454 { 455 struct vm_page **bucket; 456 457 bucket = &vm_page_buckets[vm_page_hash(m->object, m->pindex)]; 458 while (*bucket != m) { 459 if (*bucket == NULL) 460 panic("vm_page_remove(): page not found in hash"); 461 bucket = &(*bucket)->hnext; 462 } 463 *bucket = m->hnext; 464 m->hnext = NULL; 465 vm_page_bucket_generation++; 466 } 467 468 /* 469 * Now remove from the object's list of backed pages. 470 */ 471 472 TAILQ_REMOVE(&object->memq, m, listq); 473 474 /* 475 * And show that the object has one fewer resident page. 476 */ 477 478 object->resident_page_count--; 479 object->generation++; 480 481 m->object = NULL; 482 } 483 484 /* 485 * vm_page_lookup: 486 * 487 * Returns the page associated with the object/offset 488 * pair specified; if none is found, NULL is returned. 489 * 490 * NOTE: the code below does not lock. It will operate properly if 491 * an interrupt makes a change, but the generation algorithm will not 492 * operate properly in an SMP environment where both cpu's are able to run 493 * kernel code simultaneously. 494 * 495 * The object must be locked. No side effects. 496 * This routine may not block. 497 * This is a critical path routine 498 */ 499 500 vm_page_t 501 vm_page_lookup(object, pindex) 502 register vm_object_t object; 503 register vm_pindex_t pindex; 504 { 505 register vm_page_t m; 506 register struct vm_page **bucket; 507 int generation; 508 509 /* 510 * Search the hash table for this object/offset pair 511 */ 512 513 retry: 514 generation = vm_page_bucket_generation; 515 bucket = &vm_page_buckets[vm_page_hash(object, pindex)]; 516 for (m = *bucket; m != NULL; m = m->hnext) { 517 if ((m->object == object) && (m->pindex == pindex)) { 518 if (vm_page_bucket_generation != generation) 519 goto retry; 520 return (m); 521 } 522 } 523 if (vm_page_bucket_generation != generation) 524 goto retry; 525 return (NULL); 526 } 527 528 /* 529 * vm_page_rename: 530 * 531 * Move the given memory entry from its 532 * current object to the specified target object/offset. 533 * 534 * The object must be locked. 535 * This routine may not block. 536 * 537 * Note: this routine will raise itself to splvm(), the caller need not. 538 * 539 * Note: swap associated with the page must be invalidated by the move. We 540 * have to do this for several reasons: (1) we aren't freeing the 541 * page, (2) we are dirtying the page, (3) the VM system is probably 542 * moving the page from object A to B, and will then later move 543 * the backing store from A to B and we can't have a conflict. 544 * 545 * Note: we *always* dirty the page. It is necessary both for the 546 * fact that we moved it, and because we may be invalidating 547 * swap. If the page is on the cache, we have to deactivate it 548 * or vm_page_dirty() will panic. Dirty pages are not allowed 549 * on the cache. 550 */ 551 552 void 553 vm_page_rename(m, new_object, new_pindex) 554 register vm_page_t m; 555 register vm_object_t new_object; 556 vm_pindex_t new_pindex; 557 { 558 int s; 559 560 s = splvm(); 561 vm_page_remove(m); 562 vm_page_insert(m, new_object, new_pindex); 563 if (m->queue - m->pc == PQ_CACHE) 564 vm_page_deactivate(m); 565 vm_page_dirty(m); 566 splx(s); 567 } 568 569 /* 570 * vm_page_unqueue_nowakeup: 571 * 572 * vm_page_unqueue() without any wakeup 573 * 574 * This routine must be called at splhigh(). 575 * This routine may not block. 576 */ 577 578 void 579 vm_page_unqueue_nowakeup(m) 580 vm_page_t m; 581 { 582 int queue = m->queue; 583 struct vpgqueues *pq; 584 if (queue != PQ_NONE) { 585 pq = &vm_page_queues[queue]; 586 m->queue = PQ_NONE; 587 TAILQ_REMOVE(&pq->pl, m, pageq); 588 (*pq->cnt)--; 589 pq->lcnt--; 590 } 591 } 592 593 /* 594 * vm_page_unqueue: 595 * 596 * Remove a page from its queue. 597 * 598 * This routine must be called at splhigh(). 599 * This routine may not block. 600 */ 601 602 void 603 vm_page_unqueue(m) 604 vm_page_t m; 605 { 606 int queue = m->queue; 607 struct vpgqueues *pq; 608 if (queue != PQ_NONE) { 609 m->queue = PQ_NONE; 610 pq = &vm_page_queues[queue]; 611 TAILQ_REMOVE(&pq->pl, m, pageq); 612 (*pq->cnt)--; 613 pq->lcnt--; 614 if ((queue - m->pc) == PQ_CACHE) { 615 if (vm_paging_needed()) 616 pagedaemon_wakeup(); 617 } 618 } 619 } 620 621 #if PQ_L2_SIZE > 1 622 623 /* 624 * vm_page_list_find: 625 * 626 * Find a page on the specified queue with color optimization. 627 * 628 * The page coloring optimization attempts to locate a page 629 * that does not overload other nearby pages in the object in 630 * the cpu's L1 or L2 caches. We need this optimization because 631 * cpu caches tend to be physical caches, while object spaces tend 632 * to be virtual. 633 * 634 * This routine must be called at splvm(). 635 * This routine may not block. 636 * 637 * This routine may only be called from the vm_page_list_find() macro 638 * in vm_page.h 639 */ 640 vm_page_t 641 _vm_page_list_find(basequeue, index) 642 int basequeue, index; 643 { 644 int i; 645 vm_page_t m = NULL; 646 struct vpgqueues *pq; 647 648 pq = &vm_page_queues[basequeue]; 649 650 /* 651 * Note that for the first loop, index+i and index-i wind up at the 652 * same place. Even though this is not totally optimal, we've already 653 * blown it by missing the cache case so we do not care. 654 */ 655 656 for(i = PQ_L2_SIZE / 2; i > 0; --i) { 657 if ((m = TAILQ_FIRST(&pq[(index + i) & PQ_L2_MASK].pl)) != NULL) 658 break; 659 660 if ((m = TAILQ_FIRST(&pq[(index - i) & PQ_L2_MASK].pl)) != NULL) 661 break; 662 } 663 return(m); 664 } 665 666 #endif 667 668 /* 669 * vm_page_select_cache: 670 * 671 * Find a page on the cache queue with color optimization. As pages 672 * might be found, but not applicable, they are deactivated. This 673 * keeps us from using potentially busy cached pages. 674 * 675 * This routine must be called at splvm(). 676 * This routine may not block. 677 */ 678 vm_page_t 679 vm_page_select_cache(object, pindex) 680 vm_object_t object; 681 vm_pindex_t pindex; 682 { 683 vm_page_t m; 684 685 while (TRUE) { 686 m = vm_page_list_find( 687 PQ_CACHE, 688 (pindex + object->pg_color) & PQ_L2_MASK, 689 FALSE 690 ); 691 if (m && ((m->flags & (PG_BUSY|PG_UNMANAGED)) || m->busy || 692 m->hold_count || m->wire_count)) { 693 vm_page_deactivate(m); 694 continue; 695 } 696 return m; 697 } 698 } 699 700 /* 701 * vm_page_select_free: 702 * 703 * Find a free or zero page, with specified preference. We attempt to 704 * inline the nominal case and fall back to _vm_page_select_free() 705 * otherwise. 706 * 707 * This routine must be called at splvm(). 708 * This routine may not block. 709 */ 710 711 static __inline vm_page_t 712 vm_page_select_free(vm_object_t object, vm_pindex_t pindex, boolean_t prefer_zero) 713 { 714 vm_page_t m; 715 716 m = vm_page_list_find( 717 PQ_FREE, 718 (pindex + object->pg_color) & PQ_L2_MASK, 719 prefer_zero 720 ); 721 return(m); 722 } 723 724 /* 725 * vm_page_alloc: 726 * 727 * Allocate and return a memory cell associated 728 * with this VM object/offset pair. 729 * 730 * page_req classes: 731 * VM_ALLOC_NORMAL normal process request 732 * VM_ALLOC_SYSTEM system *really* needs a page 733 * VM_ALLOC_INTERRUPT interrupt time request 734 * VM_ALLOC_ZERO zero page 735 * 736 * Object must be locked. 737 * This routine may not block. 738 * 739 * Additional special handling is required when called from an 740 * interrupt (VM_ALLOC_INTERRUPT). We are not allowed to mess with 741 * the page cache in this case. 742 */ 743 744 vm_page_t 745 vm_page_alloc(object, pindex, page_req) 746 vm_object_t object; 747 vm_pindex_t pindex; 748 int page_req; 749 { 750 register vm_page_t m = NULL; 751 int s; 752 753 KASSERT(!vm_page_lookup(object, pindex), 754 ("vm_page_alloc: page already allocated")); 755 756 /* 757 * The pager is allowed to eat deeper into the free page list. 758 */ 759 760 if ((curproc == pageproc) && (page_req != VM_ALLOC_INTERRUPT)) { 761 page_req = VM_ALLOC_SYSTEM; 762 }; 763 764 s = splvm(); 765 766 loop: 767 if (cnt.v_free_count > cnt.v_free_reserved) { 768 /* 769 * Allocate from the free queue if there are plenty of pages 770 * in it. 771 */ 772 if (page_req == VM_ALLOC_ZERO) 773 m = vm_page_select_free(object, pindex, TRUE); 774 else 775 m = vm_page_select_free(object, pindex, FALSE); 776 } else if ( 777 (page_req == VM_ALLOC_SYSTEM && 778 cnt.v_cache_count == 0 && 779 cnt.v_free_count > cnt.v_interrupt_free_min) || 780 (page_req == VM_ALLOC_INTERRUPT && cnt.v_free_count > 0) 781 ) { 782 /* 783 * Interrupt or system, dig deeper into the free list. 784 */ 785 m = vm_page_select_free(object, pindex, FALSE); 786 } else if (page_req != VM_ALLOC_INTERRUPT) { 787 /* 788 * Allocatable from cache (non-interrupt only). On success, 789 * we must free the page and try again, thus ensuring that 790 * cnt.v_*_free_min counters are replenished. 791 */ 792 m = vm_page_select_cache(object, pindex); 793 if (m == NULL) { 794 splx(s); 795 #if defined(DIAGNOSTIC) 796 if (cnt.v_cache_count > 0) 797 printf("vm_page_alloc(NORMAL): missing pages on cache queue: %d\n", cnt.v_cache_count); 798 #endif 799 vm_pageout_deficit++; 800 pagedaemon_wakeup(); 801 return (NULL); 802 } 803 KASSERT(m->dirty == 0, ("Found dirty cache page %p", m)); 804 vm_page_busy(m); 805 vm_page_protect(m, VM_PROT_NONE); 806 vm_page_free(m); 807 goto loop; 808 } else { 809 /* 810 * Not allocatable from cache from interrupt, give up. 811 */ 812 splx(s); 813 vm_pageout_deficit++; 814 pagedaemon_wakeup(); 815 return (NULL); 816 } 817 818 /* 819 * At this point we had better have found a good page. 820 */ 821 822 KASSERT( 823 m != NULL, 824 ("vm_page_alloc(): missing page on free queue\n") 825 ); 826 827 /* 828 * Remove from free queue 829 */ 830 831 vm_page_unqueue_nowakeup(m); 832 833 /* 834 * Initialize structure. Only the PG_ZERO flag is inherited. 835 */ 836 837 if (m->flags & PG_ZERO) { 838 vm_page_zero_count--; 839 m->flags = PG_ZERO | PG_BUSY; 840 } else { 841 m->flags = PG_BUSY; 842 } 843 m->wire_count = 0; 844 m->hold_count = 0; 845 m->act_count = 0; 846 m->busy = 0; 847 m->valid = 0; 848 KASSERT(m->dirty == 0, ("vm_page_alloc: free/cache page %p was dirty", m)); 849 850 /* 851 * vm_page_insert() is safe prior to the splx(). Note also that 852 * inserting a page here does not insert it into the pmap (which 853 * could cause us to block allocating memory). We cannot block 854 * anywhere. 855 */ 856 857 vm_page_insert(m, object, pindex); 858 859 /* 860 * Don't wakeup too often - wakeup the pageout daemon when 861 * we would be nearly out of memory. 862 */ 863 if (vm_paging_needed()) 864 pagedaemon_wakeup(); 865 866 splx(s); 867 868 return (m); 869 } 870 871 /* 872 * vm_wait: (also see VM_WAIT macro) 873 * 874 * Block until free pages are available for allocation 875 */ 876 877 void 878 vm_wait() 879 { 880 int s; 881 882 s = splvm(); 883 if (curproc == pageproc) { 884 vm_pageout_pages_needed = 1; 885 tsleep(&vm_pageout_pages_needed, PSWP, "VMWait", 0); 886 } else { 887 if (!vm_pages_needed) { 888 vm_pages_needed = 1; 889 wakeup(&vm_pages_needed); 890 } 891 tsleep(&cnt.v_free_count, PVM, "vmwait", 0); 892 } 893 splx(s); 894 } 895 896 /* 897 * vm_await: (also see VM_AWAIT macro) 898 * 899 * asleep on an event that will signal when free pages are available 900 * for allocation. 901 */ 902 903 void 904 vm_await() 905 { 906 int s; 907 908 s = splvm(); 909 if (curproc == pageproc) { 910 vm_pageout_pages_needed = 1; 911 asleep(&vm_pageout_pages_needed, PSWP, "vmwait", 0); 912 } else { 913 if (!vm_pages_needed) { 914 vm_pages_needed++; 915 wakeup(&vm_pages_needed); 916 } 917 asleep(&cnt.v_free_count, PVM, "vmwait", 0); 918 } 919 splx(s); 920 } 921 922 #if 0 923 /* 924 * vm_page_sleep: 925 * 926 * Block until page is no longer busy. 927 */ 928 929 int 930 vm_page_sleep(vm_page_t m, char *msg, char *busy) { 931 int slept = 0; 932 if ((busy && *busy) || (m->flags & PG_BUSY)) { 933 int s; 934 s = splvm(); 935 if ((busy && *busy) || (m->flags & PG_BUSY)) { 936 vm_page_flag_set(m, PG_WANTED); 937 tsleep(m, PVM, msg, 0); 938 slept = 1; 939 } 940 splx(s); 941 } 942 return slept; 943 } 944 945 #endif 946 947 #if 0 948 949 /* 950 * vm_page_asleep: 951 * 952 * Similar to vm_page_sleep(), but does not block. Returns 0 if 953 * the page is not busy, or 1 if the page is busy. 954 * 955 * This routine has the side effect of calling asleep() if the page 956 * was busy (1 returned). 957 */ 958 959 int 960 vm_page_asleep(vm_page_t m, char *msg, char *busy) { 961 int slept = 0; 962 if ((busy && *busy) || (m->flags & PG_BUSY)) { 963 int s; 964 s = splvm(); 965 if ((busy && *busy) || (m->flags & PG_BUSY)) { 966 vm_page_flag_set(m, PG_WANTED); 967 asleep(m, PVM, msg, 0); 968 slept = 1; 969 } 970 splx(s); 971 } 972 return slept; 973 } 974 975 #endif 976 977 /* 978 * vm_page_activate: 979 * 980 * Put the specified page on the active list (if appropriate). 981 * Ensure that act_count is at least ACT_INIT but do not otherwise 982 * mess with it. 983 * 984 * The page queues must be locked. 985 * This routine may not block. 986 */ 987 void 988 vm_page_activate(m) 989 register vm_page_t m; 990 { 991 int s; 992 993 s = splvm(); 994 if (m->queue != PQ_ACTIVE) { 995 if ((m->queue - m->pc) == PQ_CACHE) 996 cnt.v_reactivated++; 997 998 vm_page_unqueue(m); 999 1000 if (m->wire_count == 0 && (m->flags & PG_UNMANAGED) == 0) { 1001 m->queue = PQ_ACTIVE; 1002 vm_page_queues[PQ_ACTIVE].lcnt++; 1003 TAILQ_INSERT_TAIL(&vm_page_queues[PQ_ACTIVE].pl, m, pageq); 1004 if (m->act_count < ACT_INIT) 1005 m->act_count = ACT_INIT; 1006 cnt.v_active_count++; 1007 } 1008 } else { 1009 if (m->act_count < ACT_INIT) 1010 m->act_count = ACT_INIT; 1011 } 1012 1013 splx(s); 1014 } 1015 1016 /* 1017 * vm_page_free_wakeup: 1018 * 1019 * Helper routine for vm_page_free_toq() and vm_page_cache(). This 1020 * routine is called when a page has been added to the cache or free 1021 * queues. 1022 * 1023 * This routine may not block. 1024 * This routine must be called at splvm() 1025 */ 1026 static __inline void 1027 vm_page_free_wakeup() 1028 { 1029 /* 1030 * if pageout daemon needs pages, then tell it that there are 1031 * some free. 1032 */ 1033 if (vm_pageout_pages_needed && 1034 cnt.v_cache_count + cnt.v_free_count >= cnt.v_pageout_free_min) { 1035 wakeup(&vm_pageout_pages_needed); 1036 vm_pageout_pages_needed = 0; 1037 } 1038 /* 1039 * wakeup processes that are waiting on memory if we hit a 1040 * high water mark. And wakeup scheduler process if we have 1041 * lots of memory. this process will swapin processes. 1042 */ 1043 if (vm_pages_needed && !vm_page_count_min()) { 1044 vm_pages_needed = 0; 1045 wakeup(&cnt.v_free_count); 1046 } 1047 } 1048 1049 /* 1050 * vm_page_free_toq: 1051 * 1052 * Returns the given page to the PQ_FREE list, 1053 * disassociating it with any VM object. 1054 * 1055 * Object and page must be locked prior to entry. 1056 * This routine may not block. 1057 */ 1058 1059 void 1060 vm_page_free_toq(vm_page_t m) 1061 { 1062 int s; 1063 struct vpgqueues *pq; 1064 vm_object_t object = m->object; 1065 1066 s = splvm(); 1067 1068 cnt.v_tfree++; 1069 1070 if (m->busy || ((m->queue - m->pc) == PQ_FREE) || 1071 (m->hold_count != 0)) { 1072 printf( 1073 "vm_page_free: pindex(%lu), busy(%d), PG_BUSY(%d), hold(%d)\n", 1074 (u_long)m->pindex, m->busy, (m->flags & PG_BUSY) ? 1 : 0, 1075 m->hold_count); 1076 if ((m->queue - m->pc) == PQ_FREE) 1077 panic("vm_page_free: freeing free page"); 1078 else 1079 panic("vm_page_free: freeing busy page"); 1080 } 1081 1082 /* 1083 * unqueue, then remove page. Note that we cannot destroy 1084 * the page here because we do not want to call the pager's 1085 * callback routine until after we've put the page on the 1086 * appropriate free queue. 1087 */ 1088 1089 vm_page_unqueue_nowakeup(m); 1090 vm_page_remove(m); 1091 1092 /* 1093 * If fictitious remove object association and 1094 * return, otherwise delay object association removal. 1095 */ 1096 1097 if ((m->flags & PG_FICTITIOUS) != 0) { 1098 splx(s); 1099 return; 1100 } 1101 1102 m->valid = 0; 1103 vm_page_undirty(m); 1104 1105 if (m->wire_count != 0) { 1106 if (m->wire_count > 1) { 1107 panic("vm_page_free: invalid wire count (%d), pindex: 0x%lx", 1108 m->wire_count, (long)m->pindex); 1109 } 1110 panic("vm_page_free: freeing wired page\n"); 1111 } 1112 1113 /* 1114 * If we've exhausted the object's resident pages we want to free 1115 * it up. 1116 */ 1117 1118 if (object && 1119 (object->type == OBJT_VNODE) && 1120 ((object->flags & OBJ_DEAD) == 0) 1121 ) { 1122 struct vnode *vp = (struct vnode *)object->handle; 1123 1124 if (vp && VSHOULDFREE(vp)) 1125 vfree(vp); 1126 } 1127 1128 /* 1129 * Clear the UNMANAGED flag when freeing an unmanaged page. 1130 */ 1131 1132 if (m->flags & PG_UNMANAGED) { 1133 m->flags &= ~PG_UNMANAGED; 1134 } else { 1135 #ifdef __alpha__ 1136 pmap_page_is_free(m); 1137 #endif 1138 } 1139 1140 m->queue = PQ_FREE + m->pc; 1141 pq = &vm_page_queues[m->queue]; 1142 pq->lcnt++; 1143 ++(*pq->cnt); 1144 1145 /* 1146 * Put zero'd pages on the end ( where we look for zero'd pages 1147 * first ) and non-zerod pages at the head. 1148 */ 1149 1150 if (m->flags & PG_ZERO) { 1151 TAILQ_INSERT_TAIL(&pq->pl, m, pageq); 1152 ++vm_page_zero_count; 1153 } else { 1154 TAILQ_INSERT_HEAD(&pq->pl, m, pageq); 1155 } 1156 1157 vm_page_free_wakeup(); 1158 1159 splx(s); 1160 } 1161 1162 /* 1163 * vm_page_unmanage: 1164 * 1165 * Prevent PV management from being done on the page. The page is 1166 * removed from the paging queues as if it were wired, and as a 1167 * consequence of no longer being managed the pageout daemon will not 1168 * touch it (since there is no way to locate the pte mappings for the 1169 * page). madvise() calls that mess with the pmap will also no longer 1170 * operate on the page. 1171 * 1172 * Beyond that the page is still reasonably 'normal'. Freeing the page 1173 * will clear the flag. 1174 * 1175 * This routine is used by OBJT_PHYS objects - objects using unswappable 1176 * physical memory as backing store rather then swap-backed memory and 1177 * will eventually be extended to support 4MB unmanaged physical 1178 * mappings. 1179 */ 1180 1181 void 1182 vm_page_unmanage(vm_page_t m) 1183 { 1184 int s; 1185 1186 s = splvm(); 1187 if ((m->flags & PG_UNMANAGED) == 0) { 1188 if (m->wire_count == 0) 1189 vm_page_unqueue(m); 1190 } 1191 vm_page_flag_set(m, PG_UNMANAGED); 1192 splx(s); 1193 } 1194 1195 /* 1196 * vm_page_wire: 1197 * 1198 * Mark this page as wired down by yet 1199 * another map, removing it from paging queues 1200 * as necessary. 1201 * 1202 * The page queues must be locked. 1203 * This routine may not block. 1204 */ 1205 void 1206 vm_page_wire(m) 1207 register vm_page_t m; 1208 { 1209 int s; 1210 1211 /* 1212 * Only bump the wire statistics if the page is not already wired, 1213 * and only unqueue the page if it is on some queue (if it is unmanaged 1214 * it is already off the queues). 1215 */ 1216 s = splvm(); 1217 if (m->wire_count == 0) { 1218 if ((m->flags & PG_UNMANAGED) == 0) 1219 vm_page_unqueue(m); 1220 cnt.v_wire_count++; 1221 } 1222 m->wire_count++; 1223 splx(s); 1224 vm_page_flag_set(m, PG_MAPPED); 1225 } 1226 1227 /* 1228 * vm_page_unwire: 1229 * 1230 * Release one wiring of this page, potentially 1231 * enabling it to be paged again. 1232 * 1233 * Many pages placed on the inactive queue should actually go 1234 * into the cache, but it is difficult to figure out which. What 1235 * we do instead, if the inactive target is well met, is to put 1236 * clean pages at the head of the inactive queue instead of the tail. 1237 * This will cause them to be moved to the cache more quickly and 1238 * if not actively re-referenced, freed more quickly. If we just 1239 * stick these pages at the end of the inactive queue, heavy filesystem 1240 * meta-data accesses can cause an unnecessary paging load on memory bound 1241 * processes. This optimization causes one-time-use metadata to be 1242 * reused more quickly. 1243 * 1244 * BUT, if we are in a low-memory situation we have no choice but to 1245 * put clean pages on the cache queue. 1246 * 1247 * A number of routines use vm_page_unwire() to guarantee that the page 1248 * will go into either the inactive or active queues, and will NEVER 1249 * be placed in the cache - for example, just after dirtying a page. 1250 * dirty pages in the cache are not allowed. 1251 * 1252 * The page queues must be locked. 1253 * This routine may not block. 1254 */ 1255 void 1256 vm_page_unwire(m, activate) 1257 register vm_page_t m; 1258 int activate; 1259 { 1260 int s; 1261 1262 s = splvm(); 1263 1264 if (m->wire_count > 0) { 1265 m->wire_count--; 1266 if (m->wire_count == 0) { 1267 cnt.v_wire_count--; 1268 if (m->flags & PG_UNMANAGED) { 1269 ; 1270 } else if (activate) { 1271 TAILQ_INSERT_TAIL(&vm_page_queues[PQ_ACTIVE].pl, m, pageq); 1272 m->queue = PQ_ACTIVE; 1273 vm_page_queues[PQ_ACTIVE].lcnt++; 1274 cnt.v_active_count++; 1275 } else { 1276 TAILQ_INSERT_TAIL(&vm_page_queues[PQ_INACTIVE].pl, m, pageq); 1277 m->queue = PQ_INACTIVE; 1278 vm_page_queues[PQ_INACTIVE].lcnt++; 1279 cnt.v_inactive_count++; 1280 } 1281 } 1282 } else { 1283 panic("vm_page_unwire: invalid wire count: %d\n", m->wire_count); 1284 } 1285 splx(s); 1286 } 1287 1288 1289 /* 1290 * Move the specified page to the inactive queue. If the page has 1291 * any associated swap, the swap is deallocated. 1292 * 1293 * Normally athead is 0 resulting in LRU operation. athead is set 1294 * to 1 if we want this page to be 'as if it were placed in the cache', 1295 * except without unmapping it from the process address space. 1296 * 1297 * This routine may not block. 1298 */ 1299 static __inline void 1300 _vm_page_deactivate(vm_page_t m, int athead) 1301 { 1302 int s; 1303 1304 /* 1305 * Ignore if already inactive. 1306 */ 1307 if (m->queue == PQ_INACTIVE) 1308 return; 1309 1310 s = splvm(); 1311 if (m->wire_count == 0 && (m->flags & PG_UNMANAGED) == 0) { 1312 if ((m->queue - m->pc) == PQ_CACHE) 1313 cnt.v_reactivated++; 1314 vm_page_unqueue(m); 1315 if (athead) 1316 TAILQ_INSERT_HEAD(&vm_page_queues[PQ_INACTIVE].pl, m, pageq); 1317 else 1318 TAILQ_INSERT_TAIL(&vm_page_queues[PQ_INACTIVE].pl, m, pageq); 1319 m->queue = PQ_INACTIVE; 1320 vm_page_queues[PQ_INACTIVE].lcnt++; 1321 cnt.v_inactive_count++; 1322 } 1323 splx(s); 1324 } 1325 1326 void 1327 vm_page_deactivate(vm_page_t m) 1328 { 1329 _vm_page_deactivate(m, 0); 1330 } 1331 1332 /* 1333 * vm_page_try_to_cache: 1334 * 1335 * Returns 0 on failure, 1 on success 1336 */ 1337 int 1338 vm_page_try_to_cache(vm_page_t m) 1339 { 1340 if (m->dirty || m->hold_count || m->busy || m->wire_count || 1341 (m->flags & (PG_BUSY|PG_UNMANAGED))) { 1342 return(0); 1343 } 1344 vm_page_test_dirty(m); 1345 if (m->dirty) 1346 return(0); 1347 vm_page_cache(m); 1348 return(1); 1349 } 1350 1351 /* 1352 * vm_page_cache 1353 * 1354 * Put the specified page onto the page cache queue (if appropriate). 1355 * 1356 * This routine may not block. 1357 */ 1358 void 1359 vm_page_cache(m) 1360 register vm_page_t m; 1361 { 1362 int s; 1363 1364 if ((m->flags & (PG_BUSY|PG_UNMANAGED)) || m->busy || m->wire_count) { 1365 printf("vm_page_cache: attempting to cache busy page\n"); 1366 return; 1367 } 1368 if ((m->queue - m->pc) == PQ_CACHE) 1369 return; 1370 1371 /* 1372 * Remove all pmaps and indicate that the page is not 1373 * writeable or mapped. 1374 */ 1375 1376 vm_page_protect(m, VM_PROT_NONE); 1377 if (m->dirty != 0) { 1378 panic("vm_page_cache: caching a dirty page, pindex: %ld", 1379 (long)m->pindex); 1380 } 1381 s = splvm(); 1382 vm_page_unqueue_nowakeup(m); 1383 m->queue = PQ_CACHE + m->pc; 1384 vm_page_queues[m->queue].lcnt++; 1385 TAILQ_INSERT_TAIL(&vm_page_queues[m->queue].pl, m, pageq); 1386 cnt.v_cache_count++; 1387 vm_page_free_wakeup(); 1388 splx(s); 1389 } 1390 1391 /* 1392 * vm_page_dontneed 1393 * 1394 * Cache, deactivate, or do nothing as appropriate. This routine 1395 * is typically used by madvise() MADV_DONTNEED. 1396 * 1397 * Generally speaking we want to move the page into the cache so 1398 * it gets reused quickly. However, this can result in a silly syndrome 1399 * due to the page recycling too quickly. Small objects will not be 1400 * fully cached. On the otherhand, if we move the page to the inactive 1401 * queue we wind up with a problem whereby very large objects 1402 * unnecessarily blow away our inactive and cache queues. 1403 * 1404 * The solution is to move the pages based on a fixed weighting. We 1405 * either leave them alone, deactivate them, or move them to the cache, 1406 * where moving them to the cache has the highest weighting. 1407 * By forcing some pages into other queues we eventually force the 1408 * system to balance the queues, potentially recovering other unrelated 1409 * space from active. The idea is to not force this to happen too 1410 * often. 1411 */ 1412 1413 void 1414 vm_page_dontneed(m) 1415 vm_page_t m; 1416 { 1417 static int dnweight; 1418 int dnw; 1419 int head; 1420 1421 dnw = ++dnweight; 1422 1423 /* 1424 * occassionally leave the page alone 1425 */ 1426 1427 if ((dnw & 0x01F0) == 0 || 1428 m->queue == PQ_INACTIVE || 1429 m->queue - m->pc == PQ_CACHE 1430 ) { 1431 if (m->act_count >= ACT_INIT) 1432 --m->act_count; 1433 return; 1434 } 1435 1436 if (m->dirty == 0) 1437 vm_page_test_dirty(m); 1438 1439 if (m->dirty || (dnw & 0x0070) == 0) { 1440 /* 1441 * Deactivate the page 3 times out of 32. 1442 */ 1443 head = 0; 1444 } else { 1445 /* 1446 * Cache the page 28 times out of every 32. Note that 1447 * the page is deactivated instead of cached, but placed 1448 * at the head of the queue instead of the tail. 1449 */ 1450 head = 1; 1451 } 1452 _vm_page_deactivate(m, head); 1453 } 1454 1455 /* 1456 * Grab a page, waiting until we are waken up due to the page 1457 * changing state. We keep on waiting, if the page continues 1458 * to be in the object. If the page doesn't exist, allocate it. 1459 * 1460 * This routine may block. 1461 */ 1462 vm_page_t 1463 vm_page_grab(object, pindex, allocflags) 1464 vm_object_t object; 1465 vm_pindex_t pindex; 1466 int allocflags; 1467 { 1468 1469 vm_page_t m; 1470 int s, generation; 1471 1472 retrylookup: 1473 if ((m = vm_page_lookup(object, pindex)) != NULL) { 1474 if (m->busy || (m->flags & PG_BUSY)) { 1475 generation = object->generation; 1476 1477 s = splvm(); 1478 while ((object->generation == generation) && 1479 (m->busy || (m->flags & PG_BUSY))) { 1480 vm_page_flag_set(m, PG_WANTED | PG_REFERENCED); 1481 tsleep(m, PVM, "pgrbwt", 0); 1482 if ((allocflags & VM_ALLOC_RETRY) == 0) { 1483 splx(s); 1484 return NULL; 1485 } 1486 } 1487 splx(s); 1488 goto retrylookup; 1489 } else { 1490 vm_page_busy(m); 1491 return m; 1492 } 1493 } 1494 1495 m = vm_page_alloc(object, pindex, allocflags & ~VM_ALLOC_RETRY); 1496 if (m == NULL) { 1497 VM_WAIT; 1498 if ((allocflags & VM_ALLOC_RETRY) == 0) 1499 return NULL; 1500 goto retrylookup; 1501 } 1502 1503 return m; 1504 } 1505 1506 /* 1507 * Mapping function for valid bits or for dirty bits in 1508 * a page. May not block. 1509 * 1510 * Inputs are required to range within a page. 1511 */ 1512 1513 __inline int 1514 vm_page_bits(int base, int size) 1515 { 1516 int first_bit; 1517 int last_bit; 1518 1519 KASSERT( 1520 base + size <= PAGE_SIZE, 1521 ("vm_page_bits: illegal base/size %d/%d", base, size) 1522 ); 1523 1524 if (size == 0) /* handle degenerate case */ 1525 return(0); 1526 1527 first_bit = base >> DEV_BSHIFT; 1528 last_bit = (base + size - 1) >> DEV_BSHIFT; 1529 1530 return ((2 << last_bit) - (1 << first_bit)); 1531 } 1532 1533 /* 1534 * vm_page_set_validclean: 1535 * 1536 * Sets portions of a page valid and clean. The arguments are expected 1537 * to be DEV_BSIZE aligned but if they aren't the bitmap is inclusive 1538 * of any partial chunks touched by the range. The invalid portion of 1539 * such chunks will be zero'd. 1540 * 1541 * This routine may not block. 1542 * 1543 * (base + size) must be less then or equal to PAGE_SIZE. 1544 */ 1545 void 1546 vm_page_set_validclean(m, base, size) 1547 vm_page_t m; 1548 int base; 1549 int size; 1550 { 1551 int pagebits; 1552 int frag; 1553 int endoff; 1554 1555 if (size == 0) /* handle degenerate case */ 1556 return; 1557 1558 /* 1559 * If the base is not DEV_BSIZE aligned and the valid 1560 * bit is clear, we have to zero out a portion of the 1561 * first block. 1562 */ 1563 1564 if ((frag = base & ~(DEV_BSIZE - 1)) != base && 1565 (m->valid & (1 << (base >> DEV_BSHIFT))) == 0 1566 ) { 1567 pmap_zero_page_area( 1568 VM_PAGE_TO_PHYS(m), 1569 frag, 1570 base - frag 1571 ); 1572 } 1573 1574 /* 1575 * If the ending offset is not DEV_BSIZE aligned and the 1576 * valid bit is clear, we have to zero out a portion of 1577 * the last block. 1578 */ 1579 1580 endoff = base + size; 1581 1582 if ((frag = endoff & ~(DEV_BSIZE - 1)) != endoff && 1583 (m->valid & (1 << (endoff >> DEV_BSHIFT))) == 0 1584 ) { 1585 pmap_zero_page_area( 1586 VM_PAGE_TO_PHYS(m), 1587 endoff, 1588 DEV_BSIZE - (endoff & (DEV_BSIZE - 1)) 1589 ); 1590 } 1591 1592 /* 1593 * Set valid, clear dirty bits. If validating the entire 1594 * page we can safely clear the pmap modify bit. We also 1595 * use this opportunity to clear the PG_NOSYNC flag. If a process 1596 * takes a write fault on a MAP_NOSYNC memory area the flag will 1597 * be set again. 1598 */ 1599 1600 pagebits = vm_page_bits(base, size); 1601 m->valid |= pagebits; 1602 m->dirty &= ~pagebits; 1603 if (base == 0 && size == PAGE_SIZE) { 1604 pmap_clear_modify(m); 1605 vm_page_flag_clear(m, PG_NOSYNC); 1606 } 1607 } 1608 1609 #if 0 1610 1611 void 1612 vm_page_set_dirty(m, base, size) 1613 vm_page_t m; 1614 int base; 1615 int size; 1616 { 1617 m->dirty |= vm_page_bits(base, size); 1618 } 1619 1620 #endif 1621 1622 void 1623 vm_page_clear_dirty(m, base, size) 1624 vm_page_t m; 1625 int base; 1626 int size; 1627 { 1628 m->dirty &= ~vm_page_bits(base, size); 1629 } 1630 1631 /* 1632 * vm_page_set_invalid: 1633 * 1634 * Invalidates DEV_BSIZE'd chunks within a page. Both the 1635 * valid and dirty bits for the effected areas are cleared. 1636 * 1637 * May not block. 1638 */ 1639 void 1640 vm_page_set_invalid(m, base, size) 1641 vm_page_t m; 1642 int base; 1643 int size; 1644 { 1645 int bits; 1646 1647 bits = vm_page_bits(base, size); 1648 m->valid &= ~bits; 1649 m->dirty &= ~bits; 1650 m->object->generation++; 1651 } 1652 1653 /* 1654 * vm_page_zero_invalid() 1655 * 1656 * The kernel assumes that the invalid portions of a page contain 1657 * garbage, but such pages can be mapped into memory by user code. 1658 * When this occurs, we must zero out the non-valid portions of the 1659 * page so user code sees what it expects. 1660 * 1661 * Pages are most often semi-valid when the end of a file is mapped 1662 * into memory and the file's size is not page aligned. 1663 */ 1664 1665 void 1666 vm_page_zero_invalid(vm_page_t m, boolean_t setvalid) 1667 { 1668 int b; 1669 int i; 1670 1671 /* 1672 * Scan the valid bits looking for invalid sections that 1673 * must be zerod. Invalid sub-DEV_BSIZE'd areas ( where the 1674 * valid bit may be set ) have already been zerod by 1675 * vm_page_set_validclean(). 1676 */ 1677 1678 for (b = i = 0; i <= PAGE_SIZE / DEV_BSIZE; ++i) { 1679 if (i == (PAGE_SIZE / DEV_BSIZE) || 1680 (m->valid & (1 << i)) 1681 ) { 1682 if (i > b) { 1683 pmap_zero_page_area( 1684 VM_PAGE_TO_PHYS(m), 1685 b << DEV_BSHIFT, 1686 (i - b) << DEV_BSHIFT 1687 ); 1688 } 1689 b = i + 1; 1690 } 1691 } 1692 1693 /* 1694 * setvalid is TRUE when we can safely set the zero'd areas 1695 * as being valid. We can do this if there are no cache consistancy 1696 * issues. e.g. it is ok to do with UFS, but not ok to do with NFS. 1697 */ 1698 1699 if (setvalid) 1700 m->valid = VM_PAGE_BITS_ALL; 1701 } 1702 1703 /* 1704 * vm_page_is_valid: 1705 * 1706 * Is (partial) page valid? Note that the case where size == 0 1707 * will return FALSE in the degenerate case where the page is 1708 * entirely invalid, and TRUE otherwise. 1709 * 1710 * May not block. 1711 */ 1712 1713 int 1714 vm_page_is_valid(m, base, size) 1715 vm_page_t m; 1716 int base; 1717 int size; 1718 { 1719 int bits = vm_page_bits(base, size); 1720 1721 if (m->valid && ((m->valid & bits) == bits)) 1722 return 1; 1723 else 1724 return 0; 1725 } 1726 1727 /* 1728 * update dirty bits from pmap/mmu. May not block. 1729 */ 1730 1731 void 1732 vm_page_test_dirty(m) 1733 vm_page_t m; 1734 { 1735 if ((m->dirty != VM_PAGE_BITS_ALL) && pmap_is_modified(m)) { 1736 vm_page_dirty(m); 1737 } 1738 } 1739 1740 /* 1741 * This interface is for merging with malloc() someday. 1742 * Even if we never implement compaction so that contiguous allocation 1743 * works after initialization time, malloc()'s data structures are good 1744 * for statistics and for allocations of less than a page. 1745 */ 1746 void * 1747 contigmalloc1(size, type, flags, low, high, alignment, boundary, map) 1748 unsigned long size; /* should be size_t here and for malloc() */ 1749 struct malloc_type *type; 1750 int flags; 1751 unsigned long low; 1752 unsigned long high; 1753 unsigned long alignment; 1754 unsigned long boundary; 1755 vm_map_t map; 1756 { 1757 int i, s, start; 1758 vm_offset_t addr, phys, tmp_addr; 1759 int pass; 1760 vm_page_t pga = vm_page_array; 1761 1762 size = round_page(size); 1763 if (size == 0) 1764 panic("contigmalloc1: size must not be 0"); 1765 if ((alignment & (alignment - 1)) != 0) 1766 panic("contigmalloc1: alignment must be a power of 2"); 1767 if ((boundary & (boundary - 1)) != 0) 1768 panic("contigmalloc1: boundary must be a power of 2"); 1769 1770 start = 0; 1771 for (pass = 0; pass <= 1; pass++) { 1772 s = splvm(); 1773 again: 1774 /* 1775 * Find first page in array that is free, within range, aligned, and 1776 * such that the boundary won't be crossed. 1777 */ 1778 for (i = start; i < cnt.v_page_count; i++) { 1779 int pqtype; 1780 phys = VM_PAGE_TO_PHYS(&pga[i]); 1781 pqtype = pga[i].queue - pga[i].pc; 1782 if (((pqtype == PQ_FREE) || (pqtype == PQ_CACHE)) && 1783 (phys >= low) && (phys < high) && 1784 ((phys & (alignment - 1)) == 0) && 1785 (((phys ^ (phys + size - 1)) & ~(boundary - 1)) == 0)) 1786 break; 1787 } 1788 1789 /* 1790 * If the above failed or we will exceed the upper bound, fail. 1791 */ 1792 if ((i == cnt.v_page_count) || 1793 ((VM_PAGE_TO_PHYS(&pga[i]) + size) > high)) { 1794 vm_page_t m, next; 1795 1796 again1: 1797 for (m = TAILQ_FIRST(&vm_page_queues[PQ_INACTIVE].pl); 1798 m != NULL; 1799 m = next) { 1800 1801 KASSERT(m->queue == PQ_INACTIVE, 1802 ("contigmalloc1: page %p is not PQ_INACTIVE", m)); 1803 1804 next = TAILQ_NEXT(m, pageq); 1805 if (vm_page_sleep_busy(m, TRUE, "vpctw0")) 1806 goto again1; 1807 vm_page_test_dirty(m); 1808 if (m->dirty) { 1809 if (m->object->type == OBJT_VNODE) { 1810 vn_lock(m->object->handle, LK_EXCLUSIVE | LK_RETRY, curproc); 1811 vm_object_page_clean(m->object, 0, 0, OBJPC_SYNC); 1812 VOP_UNLOCK(m->object->handle, 0, curproc); 1813 goto again1; 1814 } else if (m->object->type == OBJT_SWAP || 1815 m->object->type == OBJT_DEFAULT) { 1816 vm_pageout_flush(&m, 1, 0); 1817 goto again1; 1818 } 1819 } 1820 if ((m->dirty == 0) && (m->busy == 0) && (m->hold_count == 0)) 1821 vm_page_cache(m); 1822 } 1823 1824 for (m = TAILQ_FIRST(&vm_page_queues[PQ_ACTIVE].pl); 1825 m != NULL; 1826 m = next) { 1827 1828 KASSERT(m->queue == PQ_ACTIVE, 1829 ("contigmalloc1: page %p is not PQ_ACTIVE", m)); 1830 1831 next = TAILQ_NEXT(m, pageq); 1832 if (vm_page_sleep_busy(m, TRUE, "vpctw1")) 1833 goto again1; 1834 vm_page_test_dirty(m); 1835 if (m->dirty) { 1836 if (m->object->type == OBJT_VNODE) { 1837 vn_lock(m->object->handle, LK_EXCLUSIVE | LK_RETRY, curproc); 1838 vm_object_page_clean(m->object, 0, 0, OBJPC_SYNC); 1839 VOP_UNLOCK(m->object->handle, 0, curproc); 1840 goto again1; 1841 } else if (m->object->type == OBJT_SWAP || 1842 m->object->type == OBJT_DEFAULT) { 1843 vm_pageout_flush(&m, 1, 0); 1844 goto again1; 1845 } 1846 } 1847 if ((m->dirty == 0) && (m->busy == 0) && (m->hold_count == 0)) 1848 vm_page_cache(m); 1849 } 1850 1851 splx(s); 1852 continue; 1853 } 1854 start = i; 1855 1856 /* 1857 * Check successive pages for contiguous and free. 1858 */ 1859 for (i = start + 1; i < (start + size / PAGE_SIZE); i++) { 1860 int pqtype; 1861 pqtype = pga[i].queue - pga[i].pc; 1862 if ((VM_PAGE_TO_PHYS(&pga[i]) != 1863 (VM_PAGE_TO_PHYS(&pga[i - 1]) + PAGE_SIZE)) || 1864 ((pqtype != PQ_FREE) && (pqtype != PQ_CACHE))) { 1865 start++; 1866 goto again; 1867 } 1868 } 1869 1870 for (i = start; i < (start + size / PAGE_SIZE); i++) { 1871 int pqtype; 1872 vm_page_t m = &pga[i]; 1873 1874 pqtype = m->queue - m->pc; 1875 if (pqtype == PQ_CACHE) { 1876 vm_page_busy(m); 1877 vm_page_free(m); 1878 } 1879 1880 TAILQ_REMOVE(&vm_page_queues[m->queue].pl, m, pageq); 1881 vm_page_queues[m->queue].lcnt--; 1882 cnt.v_free_count--; 1883 m->valid = VM_PAGE_BITS_ALL; 1884 m->flags = 0; 1885 KASSERT(m->dirty == 0, ("contigmalloc1: page %p was dirty", m)); 1886 m->wire_count = 0; 1887 m->busy = 0; 1888 m->queue = PQ_NONE; 1889 m->object = NULL; 1890 vm_page_wire(m); 1891 } 1892 1893 /* 1894 * We've found a contiguous chunk that meets are requirements. 1895 * Allocate kernel VM, unfree and assign the physical pages to it and 1896 * return kernel VM pointer. 1897 */ 1898 tmp_addr = addr = kmem_alloc_pageable(map, size); 1899 if (addr == 0) { 1900 /* 1901 * XXX We almost never run out of kernel virtual 1902 * space, so we don't make the allocated memory 1903 * above available. 1904 */ 1905 splx(s); 1906 return (NULL); 1907 } 1908 1909 for (i = start; i < (start + size / PAGE_SIZE); i++) { 1910 vm_page_t m = &pga[i]; 1911 vm_page_insert(m, kernel_object, 1912 OFF_TO_IDX(tmp_addr - VM_MIN_KERNEL_ADDRESS)); 1913 pmap_kenter(tmp_addr, VM_PAGE_TO_PHYS(m)); 1914 tmp_addr += PAGE_SIZE; 1915 } 1916 1917 splx(s); 1918 return ((void *)addr); 1919 } 1920 return NULL; 1921 } 1922 1923 void * 1924 contigmalloc(size, type, flags, low, high, alignment, boundary) 1925 unsigned long size; /* should be size_t here and for malloc() */ 1926 struct malloc_type *type; 1927 int flags; 1928 unsigned long low; 1929 unsigned long high; 1930 unsigned long alignment; 1931 unsigned long boundary; 1932 { 1933 return contigmalloc1(size, type, flags, low, high, alignment, boundary, 1934 kernel_map); 1935 } 1936 1937 void 1938 contigfree(addr, size, type) 1939 void *addr; 1940 unsigned long size; 1941 struct malloc_type *type; 1942 { 1943 kmem_free(kernel_map, (vm_offset_t)addr, size); 1944 } 1945 1946 vm_offset_t 1947 vm_page_alloc_contig(size, low, high, alignment) 1948 vm_offset_t size; 1949 vm_offset_t low; 1950 vm_offset_t high; 1951 vm_offset_t alignment; 1952 { 1953 return ((vm_offset_t)contigmalloc1(size, M_DEVBUF, M_NOWAIT, low, high, 1954 alignment, 0ul, kernel_map)); 1955 } 1956 1957 #include "opt_ddb.h" 1958 #ifdef DDB 1959 #include <sys/kernel.h> 1960 1961 #include <ddb/ddb.h> 1962 1963 DB_SHOW_COMMAND(page, vm_page_print_page_info) 1964 { 1965 db_printf("cnt.v_free_count: %d\n", cnt.v_free_count); 1966 db_printf("cnt.v_cache_count: %d\n", cnt.v_cache_count); 1967 db_printf("cnt.v_inactive_count: %d\n", cnt.v_inactive_count); 1968 db_printf("cnt.v_active_count: %d\n", cnt.v_active_count); 1969 db_printf("cnt.v_wire_count: %d\n", cnt.v_wire_count); 1970 db_printf("cnt.v_free_reserved: %d\n", cnt.v_free_reserved); 1971 db_printf("cnt.v_free_min: %d\n", cnt.v_free_min); 1972 db_printf("cnt.v_free_target: %d\n", cnt.v_free_target); 1973 db_printf("cnt.v_cache_min: %d\n", cnt.v_cache_min); 1974 db_printf("cnt.v_inactive_target: %d\n", cnt.v_inactive_target); 1975 } 1976 1977 DB_SHOW_COMMAND(pageq, vm_page_print_pageq_info) 1978 { 1979 int i; 1980 db_printf("PQ_FREE:"); 1981 for(i=0;i<PQ_L2_SIZE;i++) { 1982 db_printf(" %d", vm_page_queues[PQ_FREE + i].lcnt); 1983 } 1984 db_printf("\n"); 1985 1986 db_printf("PQ_CACHE:"); 1987 for(i=0;i<PQ_L2_SIZE;i++) { 1988 db_printf(" %d", vm_page_queues[PQ_CACHE + i].lcnt); 1989 } 1990 db_printf("\n"); 1991 1992 db_printf("PQ_ACTIVE: %d, PQ_INACTIVE: %d\n", 1993 vm_page_queues[PQ_ACTIVE].lcnt, 1994 vm_page_queues[PQ_INACTIVE].lcnt); 1995 } 1996 #endif /* DDB */ 1997