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 * $Id: vm_page.c,v 1.132 1999/06/20 21:47:02 alc Exp $ 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 <vm/vm_prot.h> 81 #include <sys/lock.h> 82 #include <vm/vm_kern.h> 83 #include <vm/vm_object.h> 84 #include <vm/vm_page.h> 85 #include <vm/vm_pageout.h> 86 #include <vm/vm_pager.h> 87 #include <vm/vm_extern.h> 88 89 static void vm_page_queue_init __P((void)); 90 static vm_page_t vm_page_select_cache __P((vm_object_t, vm_pindex_t)); 91 92 /* 93 * Associated with page of user-allocatable memory is a 94 * page structure. 95 */ 96 97 static struct vm_page **vm_page_buckets; /* Array of buckets */ 98 static int vm_page_bucket_count; /* How big is array? */ 99 static int vm_page_hash_mask; /* Mask for hash function */ 100 static volatile int vm_page_bucket_generation; 101 102 struct pglist vm_page_queue_free[PQ_L2_SIZE] = {{0}}; 103 struct pglist vm_page_queue_active = {0}; 104 struct pglist vm_page_queue_inactive = {0}; 105 struct pglist vm_page_queue_cache[PQ_L2_SIZE] = {{0}}; 106 107 static int no_queue=0; 108 109 struct vpgqueues vm_page_queues[PQ_COUNT] = {{0}}; 110 static int pqcnt[PQ_COUNT] = {0}; 111 112 static void 113 vm_page_queue_init(void) { 114 int i; 115 116 vm_page_queues[PQ_NONE].pl = NULL; 117 vm_page_queues[PQ_NONE].cnt = &no_queue; 118 for(i=0;i<PQ_L2_SIZE;i++) { 119 vm_page_queues[PQ_FREE+i].pl = &vm_page_queue_free[i]; 120 vm_page_queues[PQ_FREE+i].cnt = &cnt.v_free_count; 121 } 122 vm_page_queues[PQ_INACTIVE].pl = &vm_page_queue_inactive; 123 vm_page_queues[PQ_INACTIVE].cnt = &cnt.v_inactive_count; 124 125 vm_page_queues[PQ_ACTIVE].pl = &vm_page_queue_active; 126 vm_page_queues[PQ_ACTIVE].cnt = &cnt.v_active_count; 127 for(i=0;i<PQ_L2_SIZE;i++) { 128 vm_page_queues[PQ_CACHE+i].pl = &vm_page_queue_cache[i]; 129 vm_page_queues[PQ_CACHE+i].cnt = &cnt.v_cache_count; 130 } 131 for(i=0;i<PQ_COUNT;i++) { 132 if (vm_page_queues[i].pl) { 133 TAILQ_INIT(vm_page_queues[i].pl); 134 } else if (i != 0) { 135 panic("vm_page_queue_init: queue %d is null", i); 136 } 137 vm_page_queues[i].lcnt = &pqcnt[i]; 138 } 139 } 140 141 vm_page_t vm_page_array = 0; 142 static int vm_page_array_size = 0; 143 long first_page = 0; 144 int vm_page_zero_count = 0; 145 146 static __inline int vm_page_hash __P((vm_object_t object, vm_pindex_t pindex)); 147 static void vm_page_free_wakeup __P((void)); 148 149 /* 150 * vm_set_page_size: 151 * 152 * Sets the page size, perhaps based upon the memory 153 * size. Must be called before any use of page-size 154 * dependent functions. 155 */ 156 void 157 vm_set_page_size() 158 { 159 if (cnt.v_page_size == 0) 160 cnt.v_page_size = PAGE_SIZE; 161 if (((cnt.v_page_size - 1) & cnt.v_page_size) != 0) 162 panic("vm_set_page_size: page size not a power of two"); 163 } 164 165 /* 166 * vm_page_startup: 167 * 168 * Initializes the resident memory module. 169 * 170 * Allocates memory for the page cells, and 171 * for the object/offset-to-page hash table headers. 172 * Each page cell is initialized and placed on the free list. 173 */ 174 175 vm_offset_t 176 vm_page_startup(starta, enda, vaddr) 177 register vm_offset_t starta; 178 vm_offset_t enda; 179 register vm_offset_t vaddr; 180 { 181 register vm_offset_t mapped; 182 register vm_page_t m; 183 register struct vm_page **bucket; 184 vm_size_t npages, page_range; 185 register vm_offset_t new_start; 186 int i; 187 vm_offset_t pa; 188 int nblocks; 189 vm_offset_t first_managed_page; 190 191 /* the biggest memory array is the second group of pages */ 192 vm_offset_t start; 193 vm_offset_t biggestone, biggestsize; 194 195 vm_offset_t total; 196 197 total = 0; 198 biggestsize = 0; 199 biggestone = 0; 200 nblocks = 0; 201 vaddr = round_page(vaddr); 202 203 for (i = 0; phys_avail[i + 1]; i += 2) { 204 phys_avail[i] = round_page(phys_avail[i]); 205 phys_avail[i + 1] = trunc_page(phys_avail[i + 1]); 206 } 207 208 for (i = 0; phys_avail[i + 1]; i += 2) { 209 int size = phys_avail[i + 1] - phys_avail[i]; 210 211 if (size > biggestsize) { 212 biggestone = i; 213 biggestsize = size; 214 } 215 ++nblocks; 216 total += size; 217 } 218 219 start = phys_avail[biggestone]; 220 221 /* 222 * Initialize the queue headers for the free queue, the active queue 223 * and the inactive queue. 224 */ 225 226 vm_page_queue_init(); 227 228 /* 229 * Allocate (and initialize) the hash table buckets. 230 * 231 * The number of buckets MUST BE a power of 2, and the actual value is 232 * the next power of 2 greater than the number of physical pages in 233 * the system. 234 * 235 * We make the hash table approximately 2x the number of pages to 236 * reduce the chain length. This is about the same size using the 237 * singly-linked list as the 1x hash table we were using before 238 * using TAILQ but the chain length will be smaller. 239 * 240 * Note: This computation can be tweaked if desired. 241 */ 242 vm_page_buckets = (struct vm_page **)vaddr; 243 bucket = vm_page_buckets; 244 if (vm_page_bucket_count == 0) { 245 vm_page_bucket_count = 1; 246 while (vm_page_bucket_count < atop(total)) 247 vm_page_bucket_count <<= 1; 248 } 249 vm_page_bucket_count <<= 1; 250 vm_page_hash_mask = vm_page_bucket_count - 1; 251 252 /* 253 * Validate these addresses. 254 */ 255 256 new_start = start + vm_page_bucket_count * sizeof(struct vm_page *); 257 new_start = round_page(new_start); 258 mapped = round_page(vaddr); 259 vaddr = pmap_map(mapped, start, new_start, 260 VM_PROT_READ | VM_PROT_WRITE); 261 start = new_start; 262 vaddr = round_page(vaddr); 263 bzero((caddr_t) mapped, vaddr - mapped); 264 265 for (i = 0; i < vm_page_bucket_count; i++) { 266 *bucket = NULL; 267 bucket++; 268 } 269 270 /* 271 * Compute the number of pages of memory that will be available for 272 * use (taking into account the overhead of a page structure per 273 * page). 274 */ 275 276 first_page = phys_avail[0] / PAGE_SIZE; 277 278 page_range = phys_avail[(nblocks - 1) * 2 + 1] / PAGE_SIZE - first_page; 279 npages = (total - (page_range * sizeof(struct vm_page)) - 280 (start - phys_avail[biggestone])) / PAGE_SIZE; 281 282 /* 283 * Initialize the mem entry structures now, and put them in the free 284 * queue. 285 */ 286 vm_page_array = (vm_page_t) vaddr; 287 mapped = vaddr; 288 289 /* 290 * Validate these addresses. 291 */ 292 new_start = round_page(start + page_range * sizeof(struct vm_page)); 293 mapped = pmap_map(mapped, start, new_start, 294 VM_PROT_READ | VM_PROT_WRITE); 295 start = new_start; 296 297 first_managed_page = start / PAGE_SIZE; 298 299 /* 300 * Clear all of the page structures 301 */ 302 bzero((caddr_t) vm_page_array, page_range * sizeof(struct vm_page)); 303 vm_page_array_size = page_range; 304 305 /* 306 * Construct the free queue(s) in descending order (by physical 307 * address) so that the first 16MB of physical memory is allocated 308 * last rather than first. On large-memory machines, this avoids 309 * the exhaustion of low physical memory before isa_dmainit has run. 310 */ 311 cnt.v_page_count = 0; 312 cnt.v_free_count = 0; 313 for (i = 0; phys_avail[i + 1] && npages > 0; i += 2) { 314 if (i == biggestone) 315 pa = ptoa(first_managed_page); 316 else 317 pa = phys_avail[i]; 318 while (pa < phys_avail[i + 1] && npages-- > 0) { 319 ++cnt.v_page_count; 320 ++cnt.v_free_count; 321 m = PHYS_TO_VM_PAGE(pa); 322 m->phys_addr = pa; 323 m->flags = 0; 324 m->pc = (pa >> PAGE_SHIFT) & PQ_L2_MASK; 325 m->queue = m->pc + PQ_FREE; 326 TAILQ_INSERT_HEAD(vm_page_queues[m->queue].pl, m, pageq); 327 ++(*vm_page_queues[m->queue].lcnt); 328 pa += PAGE_SIZE; 329 } 330 } 331 return (mapped); 332 } 333 334 /* 335 * vm_page_hash: 336 * 337 * Distributes the object/offset key pair among hash buckets. 338 * 339 * NOTE: This macro depends on vm_page_bucket_count being a power of 2. 340 * This routine may not block. 341 * 342 * We try to randomize the hash based on the object to spread the pages 343 * out in the hash table without it costing us too much. 344 */ 345 static __inline int 346 vm_page_hash(object, pindex) 347 vm_object_t object; 348 vm_pindex_t pindex; 349 { 350 int i = ((uintptr_t)object + pindex) ^ object->hash_rand; 351 352 return(i & vm_page_hash_mask); 353 } 354 355 /* 356 * vm_page_insert: [ internal use only ] 357 * 358 * Inserts the given mem entry into the object and object list. 359 * 360 * The pagetables are not updated but will presumably fault the page 361 * in if necessary, or if a kernel page the caller will at some point 362 * enter the page into the kernel's pmap. We are not allowed to block 363 * here so we *can't* do this anyway. 364 * 365 * The object and page must be locked, and must be splhigh. 366 * This routine may not block. 367 */ 368 369 void 370 vm_page_insert(m, object, pindex) 371 register vm_page_t m; 372 register vm_object_t object; 373 register vm_pindex_t pindex; 374 { 375 register struct vm_page **bucket; 376 377 if (m->object != NULL) 378 panic("vm_page_insert: already inserted"); 379 380 /* 381 * Record the object/offset pair in this page 382 */ 383 384 m->object = object; 385 m->pindex = pindex; 386 387 /* 388 * Insert it into the object_object/offset hash table 389 */ 390 391 bucket = &vm_page_buckets[vm_page_hash(object, pindex)]; 392 m->hnext = *bucket; 393 *bucket = m; 394 vm_page_bucket_generation++; 395 396 /* 397 * Now link into the object's list of backed pages. 398 */ 399 400 TAILQ_INSERT_TAIL(&object->memq, m, listq); 401 m->object->generation++; 402 403 /* 404 * show that the object has one more resident page. 405 */ 406 407 object->resident_page_count++; 408 409 /* 410 * Since we are inserting a new and possibly dirty page, 411 * update the object's OBJ_WRITEABLE and OBJ_MIGHTBEDIRTY flags. 412 */ 413 if (m->flags & PG_WRITEABLE) 414 vm_object_set_flag(object, OBJ_WRITEABLE|OBJ_MIGHTBEDIRTY); 415 } 416 417 /* 418 * vm_page_remove: 419 * NOTE: used by device pager as well -wfj 420 * 421 * Removes the given mem entry from the object/offset-page 422 * table and the object page list, but do not invalidate/terminate 423 * the backing store. 424 * 425 * The object and page must be locked, and at splhigh. 426 * The underlying pmap entry (if any) is NOT removed here. 427 * This routine may not block. 428 */ 429 430 void 431 vm_page_remove(m) 432 vm_page_t m; 433 { 434 vm_object_t object; 435 436 if (m->object == NULL) 437 return; 438 439 #if !defined(MAX_PERF) 440 if ((m->flags & PG_BUSY) == 0) { 441 panic("vm_page_remove: page not busy"); 442 } 443 #endif 444 445 /* 446 * Basically destroy the page. 447 */ 448 449 vm_page_wakeup(m); 450 451 object = m->object; 452 453 /* 454 * Remove from the object_object/offset hash table. The object 455 * must be on the hash queue, we will panic if it isn't 456 * 457 * Note: we must NULL-out m->hnext to prevent loops in detached 458 * buffers with vm_page_lookup(). 459 */ 460 461 { 462 struct vm_page **bucket; 463 464 bucket = &vm_page_buckets[vm_page_hash(m->object, m->pindex)]; 465 while (*bucket != m) { 466 #if !defined(MAX_PERF) 467 if (*bucket == NULL) 468 panic("vm_page_remove(): page not found in hash"); 469 #endif 470 bucket = &(*bucket)->hnext; 471 } 472 *bucket = m->hnext; 473 m->hnext = NULL; 474 vm_page_bucket_generation++; 475 } 476 477 /* 478 * Now remove from the object's list of backed pages. 479 */ 480 481 TAILQ_REMOVE(&object->memq, m, listq); 482 483 /* 484 * And show that the object has one fewer resident page. 485 */ 486 487 object->resident_page_count--; 488 object->generation++; 489 490 m->object = NULL; 491 } 492 493 /* 494 * vm_page_lookup: 495 * 496 * Returns the page associated with the object/offset 497 * pair specified; if none is found, NULL is returned. 498 * 499 * NOTE: the code below does not lock. It will operate properly if 500 * an interrupt makes a change, but the generation algorithm will not 501 * operate properly in an SMP environment where both cpu's are able to run 502 * kernel code simultaniously. 503 * 504 * The object must be locked. No side effects. 505 * This routine may not block. 506 * This is a critical path routine 507 */ 508 509 vm_page_t 510 vm_page_lookup(object, pindex) 511 register vm_object_t object; 512 register vm_pindex_t pindex; 513 { 514 register vm_page_t m; 515 register struct vm_page **bucket; 516 int generation; 517 518 /* 519 * Search the hash table for this object/offset pair 520 */ 521 522 retry: 523 generation = vm_page_bucket_generation; 524 bucket = &vm_page_buckets[vm_page_hash(object, pindex)]; 525 for (m = *bucket; m != NULL; m = m->hnext) { 526 if ((m->object == object) && (m->pindex == pindex)) { 527 if (vm_page_bucket_generation != generation) 528 goto retry; 529 return (m); 530 } 531 } 532 if (vm_page_bucket_generation != generation) 533 goto retry; 534 return (NULL); 535 } 536 537 /* 538 * vm_page_rename: 539 * 540 * Move the given memory entry from its 541 * current object to the specified target object/offset. 542 * 543 * The object must be locked. 544 * This routine may not block. 545 * 546 * Note: this routine will raise itself to splvm(), the caller need not. 547 * 548 * Note: swap associated with the page must be invalidated by the move. We 549 * have to do this for several reasons: (1) we aren't freeing the 550 * page, (2) we are dirtying the page, (3) the VM system is probably 551 * moving the page from object A to B, and will then later move 552 * the backing store from A to B and we can't have a conflict. 553 * 554 * Note: we *always* dirty the page. It is necessary both for the 555 * fact that we moved it, and because we may be invalidating 556 * swap. If the page is on the cache, we have to deactivate it 557 * or vm_page_dirty() will panic. Dirty pages are not allowed 558 * on the cache. 559 */ 560 561 void 562 vm_page_rename(m, new_object, new_pindex) 563 register vm_page_t m; 564 register vm_object_t new_object; 565 vm_pindex_t new_pindex; 566 { 567 int s; 568 569 s = splvm(); 570 vm_page_remove(m); 571 vm_page_insert(m, new_object, new_pindex); 572 if (m->queue - m->pc == PQ_CACHE) 573 vm_page_deactivate(m); 574 vm_page_dirty(m); 575 splx(s); 576 } 577 578 /* 579 * vm_page_unqueue_nowakeup: 580 * 581 * vm_page_unqueue() without any wakeup 582 * 583 * This routine must be called at splhigh(). 584 * This routine may not block. 585 */ 586 587 void 588 vm_page_unqueue_nowakeup(m) 589 vm_page_t m; 590 { 591 int queue = m->queue; 592 struct vpgqueues *pq; 593 if (queue != PQ_NONE) { 594 pq = &vm_page_queues[queue]; 595 m->queue = PQ_NONE; 596 TAILQ_REMOVE(pq->pl, m, pageq); 597 (*pq->cnt)--; 598 (*pq->lcnt)--; 599 } 600 } 601 602 /* 603 * vm_page_unqueue: 604 * 605 * Remove a page from its queue. 606 * 607 * This routine must be called at splhigh(). 608 * This routine may not block. 609 */ 610 611 void 612 vm_page_unqueue(m) 613 vm_page_t m; 614 { 615 int queue = m->queue; 616 struct vpgqueues *pq; 617 if (queue != PQ_NONE) { 618 m->queue = PQ_NONE; 619 pq = &vm_page_queues[queue]; 620 TAILQ_REMOVE(pq->pl, m, pageq); 621 (*pq->cnt)--; 622 (*pq->lcnt)--; 623 if ((queue - m->pc) == PQ_CACHE) { 624 if ((cnt.v_cache_count + cnt.v_free_count) < 625 (cnt.v_free_reserved + cnt.v_cache_min)) 626 pagedaemon_wakeup(); 627 } 628 } 629 } 630 631 #if PQ_L2_SIZE > 1 632 633 /* 634 * vm_page_list_find: 635 * 636 * Find a page on the specified queue with color optimization. 637 * 638 * The page coloring optimization attempts to locate a page 639 * that does not overload other nearby pages in the object in 640 * the cpu's L1 or L2 caches. We need this optmization because 641 * cpu caches tend to be physical caches, while object spaces tend 642 * to be virtual. 643 * 644 * This routine must be called at splvm(). 645 * This routine may not block. 646 * 647 * This routine may only be called from the vm_page_list_find() macro 648 * in vm_page.h 649 */ 650 vm_page_t 651 _vm_page_list_find(basequeue, index) 652 int basequeue, index; 653 { 654 int i; 655 vm_page_t m = NULL; 656 struct vpgqueues *pq; 657 658 pq = &vm_page_queues[basequeue]; 659 660 /* 661 * Note that for the first loop, index+i and index-i wind up at the 662 * same place. Even though this is not totally optimal, we've already 663 * blown it by missing the cache case so we do not care. 664 */ 665 666 for(i = PQ_L2_SIZE / 2; i > 0; --i) { 667 if ((m = TAILQ_FIRST(pq[(index + i) & PQ_L2_MASK].pl)) != NULL) 668 break; 669 670 if ((m = TAILQ_FIRST(pq[(index - i) & PQ_L2_MASK].pl)) != NULL) 671 break; 672 } 673 return(m); 674 } 675 676 #endif 677 678 /* 679 * vm_page_select_cache: 680 * 681 * Find a page on the cache queue with color optimization. As pages 682 * might be found, but not applicable, they are deactivated. This 683 * keeps us from using potentially busy cached pages. 684 * 685 * This routine must be called at splvm(). 686 * This routine may not block. 687 */ 688 vm_page_t 689 vm_page_select_cache(object, pindex) 690 vm_object_t object; 691 vm_pindex_t pindex; 692 { 693 vm_page_t m; 694 695 while (TRUE) { 696 m = vm_page_list_find( 697 PQ_CACHE, 698 (pindex + object->pg_color) & PQ_L2_MASK, 699 FALSE 700 ); 701 if (m && ((m->flags & PG_BUSY) || m->busy || 702 m->hold_count || m->wire_count)) { 703 vm_page_deactivate(m); 704 continue; 705 } 706 return m; 707 } 708 } 709 710 /* 711 * vm_page_select_free: 712 * 713 * Find a free or zero page, with specified preference. We attempt to 714 * inline the nominal case and fall back to _vm_page_select_free() 715 * otherwise. 716 * 717 * This routine must be called at splvm(). 718 * This routine may not block. 719 */ 720 721 static __inline vm_page_t 722 vm_page_select_free(vm_object_t object, vm_pindex_t pindex, boolean_t prefer_zero) 723 { 724 vm_page_t m; 725 726 m = vm_page_list_find( 727 PQ_FREE, 728 (pindex + object->pg_color) & PQ_L2_MASK, 729 prefer_zero 730 ); 731 return(m); 732 } 733 734 /* 735 * vm_page_alloc: 736 * 737 * Allocate and return a memory cell associated 738 * with this VM object/offset pair. 739 * 740 * page_req classes: 741 * VM_ALLOC_NORMAL normal process request 742 * VM_ALLOC_SYSTEM system *really* needs a page 743 * VM_ALLOC_INTERRUPT interrupt time request 744 * VM_ALLOC_ZERO zero page 745 * 746 * Object must be locked. 747 * This routine may not block. 748 * 749 * Additional special handling is required when called from an 750 * interrupt (VM_ALLOC_INTERRUPT). We are not allowed to mess with 751 * the page cache in this case. 752 */ 753 754 vm_page_t 755 vm_page_alloc(object, pindex, page_req) 756 vm_object_t object; 757 vm_pindex_t pindex; 758 int page_req; 759 { 760 register vm_page_t m = NULL; 761 int s; 762 763 KASSERT(!vm_page_lookup(object, pindex), 764 ("vm_page_alloc: page already allocated")); 765 766 /* 767 * The pager is allowed to eat deeper into the free page list. 768 */ 769 770 if ((curproc == pageproc) && (page_req != VM_ALLOC_INTERRUPT)) { 771 page_req = VM_ALLOC_SYSTEM; 772 }; 773 774 s = splvm(); 775 776 loop: 777 if (cnt.v_free_count > cnt.v_free_reserved) { 778 /* 779 * Allocate from the free queue if there are plenty of pages 780 * in it. 781 */ 782 if (page_req == VM_ALLOC_ZERO) 783 m = vm_page_select_free(object, pindex, TRUE); 784 else 785 m = vm_page_select_free(object, pindex, FALSE); 786 } else if ( 787 (page_req == VM_ALLOC_SYSTEM && 788 cnt.v_cache_count == 0 && 789 cnt.v_free_count > cnt.v_interrupt_free_min) || 790 (page_req == VM_ALLOC_INTERRUPT && cnt.v_free_count > 0) 791 ) { 792 /* 793 * Interrupt or system, dig deeper into the free list. 794 */ 795 m = vm_page_select_free(object, pindex, FALSE); 796 } else if (page_req != VM_ALLOC_INTERRUPT) { 797 /* 798 * Allocateable from cache (non-interrupt only). On success, 799 * we must free the page and try again, thus ensuring that 800 * cnt.v_*_free_min counters are replenished. 801 */ 802 m = vm_page_select_cache(object, pindex); 803 if (m == NULL) { 804 splx(s); 805 #if defined(DIAGNOSTIC) 806 if (cnt.v_cache_count > 0) 807 printf("vm_page_alloc(NORMAL): missing pages on cache queue: %d\n", cnt.v_cache_count); 808 #endif 809 vm_pageout_deficit++; 810 pagedaemon_wakeup(); 811 return (NULL); 812 } 813 KASSERT(m->dirty == 0, ("Found dirty cache page %p", m)); 814 vm_page_busy(m); 815 vm_page_protect(m, VM_PROT_NONE); 816 vm_page_free(m); 817 goto loop; 818 } else { 819 /* 820 * Not allocateable from cache from interrupt, give up. 821 */ 822 splx(s); 823 vm_pageout_deficit++; 824 pagedaemon_wakeup(); 825 return (NULL); 826 } 827 828 /* 829 * At this point we had better have found a good page. 830 */ 831 832 KASSERT( 833 m != NULL, 834 ("vm_page_alloc(): missing page on free queue\n") 835 ); 836 837 /* 838 * Remove from free queue 839 */ 840 841 { 842 struct vpgqueues *pq = &vm_page_queues[m->queue]; 843 844 TAILQ_REMOVE(pq->pl, m, pageq); 845 (*pq->cnt)--; 846 (*pq->lcnt)--; 847 } 848 849 /* 850 * Initialize structure. Only the PG_ZERO flag is inherited. 851 */ 852 853 if (m->flags & PG_ZERO) { 854 vm_page_zero_count--; 855 m->flags = PG_ZERO | PG_BUSY; 856 } else { 857 m->flags = PG_BUSY; 858 } 859 m->wire_count = 0; 860 m->hold_count = 0; 861 m->act_count = 0; 862 m->busy = 0; 863 m->valid = 0; 864 m->dirty = 0; 865 m->queue = PQ_NONE; 866 867 /* 868 * vm_page_insert() is safe prior to the splx(). Note also that 869 * inserting a page here does not insert it into the pmap (which 870 * could cause us to block allocating memory). We cannot block 871 * anywhere. 872 */ 873 874 vm_page_insert(m, object, 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 (((cnt.v_free_count + cnt.v_cache_count) < 881 (cnt.v_free_reserved + cnt.v_cache_min)) || 882 (cnt.v_free_count < cnt.v_pageout_free_min)) 883 pagedaemon_wakeup(); 884 885 splx(s); 886 887 return (m); 888 } 889 890 /* 891 * vm_wait: (also see VM_WAIT macro) 892 * 893 * Block until free pages are available for allocation 894 */ 895 896 void 897 vm_wait() 898 { 899 int s; 900 901 s = splvm(); 902 if (curproc == pageproc) { 903 vm_pageout_pages_needed = 1; 904 tsleep(&vm_pageout_pages_needed, PSWP, "vmwait", 0); 905 } else { 906 if (!vm_pages_needed) { 907 vm_pages_needed++; 908 wakeup(&vm_pages_needed); 909 } 910 tsleep(&cnt.v_free_count, PVM, "vmwait", 0); 911 } 912 splx(s); 913 } 914 915 /* 916 * vm_await: (also see VM_AWAIT macro) 917 * 918 * asleep on an event that will signal when free pages are available 919 * for allocation. 920 */ 921 922 void 923 vm_await() 924 { 925 int s; 926 927 s = splvm(); 928 if (curproc == pageproc) { 929 vm_pageout_pages_needed = 1; 930 asleep(&vm_pageout_pages_needed, PSWP, "vmwait", 0); 931 } else { 932 if (!vm_pages_needed) { 933 vm_pages_needed++; 934 wakeup(&vm_pages_needed); 935 } 936 asleep(&cnt.v_free_count, PVM, "vmwait", 0); 937 } 938 splx(s); 939 } 940 941 #if 0 942 /* 943 * vm_page_sleep: 944 * 945 * Block until page is no longer busy. 946 */ 947 948 int 949 vm_page_sleep(vm_page_t m, char *msg, char *busy) { 950 int slept = 0; 951 if ((busy && *busy) || (m->flags & PG_BUSY)) { 952 int s; 953 s = splvm(); 954 if ((busy && *busy) || (m->flags & PG_BUSY)) { 955 vm_page_flag_set(m, PG_WANTED); 956 tsleep(m, PVM, msg, 0); 957 slept = 1; 958 } 959 splx(s); 960 } 961 return slept; 962 } 963 964 #endif 965 966 #if 0 967 968 /* 969 * vm_page_asleep: 970 * 971 * Similar to vm_page_sleep(), but does not block. Returns 0 if 972 * the page is not busy, or 1 if the page is busy. 973 * 974 * This routine has the side effect of calling asleep() if the page 975 * was busy (1 returned). 976 */ 977 978 int 979 vm_page_asleep(vm_page_t m, char *msg, char *busy) { 980 int slept = 0; 981 if ((busy && *busy) || (m->flags & PG_BUSY)) { 982 int s; 983 s = splvm(); 984 if ((busy && *busy) || (m->flags & PG_BUSY)) { 985 vm_page_flag_set(m, PG_WANTED); 986 asleep(m, PVM, msg, 0); 987 slept = 1; 988 } 989 splx(s); 990 } 991 return slept; 992 } 993 994 #endif 995 996 /* 997 * vm_page_activate: 998 * 999 * Put the specified page on the active list (if appropriate). 1000 * 1001 * The page queues must be locked. 1002 * This routine may not block. 1003 */ 1004 void 1005 vm_page_activate(m) 1006 register vm_page_t m; 1007 { 1008 int s; 1009 1010 s = splvm(); 1011 if (m->queue != PQ_ACTIVE) { 1012 if ((m->queue - m->pc) == PQ_CACHE) 1013 cnt.v_reactivated++; 1014 1015 vm_page_unqueue(m); 1016 1017 if (m->wire_count == 0) { 1018 m->queue = PQ_ACTIVE; 1019 ++(*vm_page_queues[PQ_ACTIVE].lcnt); 1020 TAILQ_INSERT_TAIL(&vm_page_queue_active, m, pageq); 1021 if (m->act_count < ACT_INIT) 1022 m->act_count = ACT_INIT; 1023 cnt.v_active_count++; 1024 } 1025 } else { 1026 if (m->act_count < ACT_INIT) 1027 m->act_count = ACT_INIT; 1028 } 1029 1030 splx(s); 1031 } 1032 1033 /* 1034 * vm_page_free_wakeup: 1035 * 1036 * Helper routine for vm_page_free_toq() and vm_page_cache(). This 1037 * routine is called when a page has been added to the cache or free 1038 * queues. 1039 * 1040 * This routine may not block. 1041 * This routine must be called at splvm() 1042 */ 1043 static __inline void 1044 vm_page_free_wakeup() 1045 { 1046 /* 1047 * if pageout daemon needs pages, then tell it that there are 1048 * some free. 1049 */ 1050 if (vm_pageout_pages_needed) { 1051 wakeup(&vm_pageout_pages_needed); 1052 vm_pageout_pages_needed = 0; 1053 } 1054 /* 1055 * wakeup processes that are waiting on memory if we hit a 1056 * high water mark. And wakeup scheduler process if we have 1057 * lots of memory. this process will swapin processes. 1058 */ 1059 if (vm_pages_needed && 1060 ((cnt.v_free_count + cnt.v_cache_count) >= cnt.v_free_min)) { 1061 wakeup(&cnt.v_free_count); 1062 vm_pages_needed = 0; 1063 } 1064 } 1065 1066 /* 1067 * vm_page_free_toq: 1068 * 1069 * Returns the given page to the PQ_FREE or PQ_ZERO list, 1070 * disassociating it with any VM object. 1071 * 1072 * Object and page must be locked prior to entry. 1073 * This routine may not block. 1074 */ 1075 1076 void 1077 vm_page_free_toq(vm_page_t m) 1078 { 1079 int s; 1080 struct vpgqueues *pq; 1081 vm_object_t object = m->object; 1082 1083 s = splvm(); 1084 1085 cnt.v_tfree++; 1086 1087 #if !defined(MAX_PERF) 1088 if (m->busy || ((m->queue - m->pc) == PQ_FREE) || 1089 (m->hold_count != 0)) { 1090 printf( 1091 "vm_page_free: pindex(%lu), busy(%d), PG_BUSY(%d), hold(%d)\n", 1092 (u_long)m->pindex, m->busy, (m->flags & PG_BUSY) ? 1 : 0, 1093 m->hold_count); 1094 if ((m->queue - m->pc) == PQ_FREE) 1095 panic("vm_page_free: freeing free page"); 1096 else 1097 panic("vm_page_free: freeing busy page"); 1098 } 1099 #endif 1100 1101 /* 1102 * unqueue, then remove page. Note that we cannot destroy 1103 * the page here because we do not want to call the pager's 1104 * callback routine until after we've put the page on the 1105 * appropriate free queue. 1106 */ 1107 1108 vm_page_unqueue_nowakeup(m); 1109 vm_page_remove(m); 1110 1111 /* 1112 * If fictitious remove object association and 1113 * return, otherwise delay object association removal. 1114 */ 1115 1116 if ((m->flags & PG_FICTITIOUS) != 0) { 1117 splx(s); 1118 return; 1119 } 1120 1121 m->valid = 0; 1122 1123 if (m->wire_count != 0) { 1124 #if !defined(MAX_PERF) 1125 if (m->wire_count > 1) { 1126 panic("vm_page_free: invalid wire count (%d), pindex: 0x%x", 1127 m->wire_count, m->pindex); 1128 } 1129 #endif 1130 printf("vm_page_free: freeing wired page\n"); 1131 m->wire_count = 0; 1132 cnt.v_wire_count--; 1133 } 1134 1135 /* 1136 * If we've exhausted the object's resident pages we want to free 1137 * it up. 1138 */ 1139 1140 if (object && 1141 (object->type == OBJT_VNODE) && 1142 ((object->flags & OBJ_DEAD) == 0) 1143 ) { 1144 struct vnode *vp = (struct vnode *)object->handle; 1145 1146 if (vp && VSHOULDFREE(vp)) { 1147 if ((vp->v_flag & (VTBFREE|VDOOMED|VFREE)) == 0) { 1148 TAILQ_INSERT_TAIL(&vnode_tobefree_list, vp, v_freelist); 1149 vp->v_flag |= VTBFREE; 1150 } 1151 } 1152 } 1153 1154 #ifdef __alpha__ 1155 pmap_page_is_free(m); 1156 #endif 1157 1158 m->queue = PQ_FREE + m->pc; 1159 pq = &vm_page_queues[m->queue]; 1160 ++(*pq->lcnt); 1161 ++(*pq->cnt); 1162 1163 /* 1164 * Put zero'd pages on the end ( where we look for zero'd pages 1165 * first ) and non-zerod pages at the head. 1166 */ 1167 1168 if (m->flags & PG_ZERO) { 1169 TAILQ_INSERT_TAIL(pq->pl, m, pageq); 1170 ++vm_page_zero_count; 1171 } else if (curproc == pageproc) { 1172 /* 1173 * If the pageout daemon is freeing pages, the pages are 1174 * likely to NOT be in the L1 or L2 caches due to their age. 1175 * For now we do not try to do anything special with this 1176 * info. 1177 */ 1178 TAILQ_INSERT_HEAD(pq->pl, m, pageq); 1179 } else { 1180 TAILQ_INSERT_HEAD(pq->pl, m, pageq); 1181 } 1182 1183 vm_page_free_wakeup(); 1184 1185 splx(s); 1186 } 1187 1188 /* 1189 * vm_page_wire: 1190 * 1191 * Mark this page as wired down by yet 1192 * another map, removing it from paging queues 1193 * as necessary. 1194 * 1195 * The page queues must be locked. 1196 * This routine may not block. 1197 */ 1198 void 1199 vm_page_wire(m) 1200 register vm_page_t m; 1201 { 1202 int s; 1203 1204 s = splvm(); 1205 if (m->wire_count == 0) { 1206 vm_page_unqueue(m); 1207 cnt.v_wire_count++; 1208 } 1209 m->wire_count++; 1210 splx(s); 1211 (*vm_page_queues[PQ_NONE].lcnt)++; 1212 vm_page_flag_set(m, PG_MAPPED); 1213 } 1214 1215 /* 1216 * vm_page_unwire: 1217 * 1218 * Release one wiring of this page, potentially 1219 * enabling it to be paged again. 1220 * 1221 * Many pages placed on the inactive queue should actually go 1222 * into the cache, but it is difficult to figure out which. What 1223 * we do instead, if the inactive target is well met, is to put 1224 * clean pages at the head of the inactive queue instead of the tail. 1225 * This will cause them to be moved to the cache more quickly and 1226 * if not actively re-referenced, freed more quickly. If we just 1227 * stick these pages at the end of the inactive queue, heavy filesystem 1228 * meta-data accesses can cause an unnecessary paging load on memory bound 1229 * processes. This optimization causes one-time-use metadata to be 1230 * reused more quickly. 1231 * 1232 * A number of routines use vm_page_unwire() to guarentee that the page 1233 * will go into either the inactive or active queues, and will NEVER 1234 * be placed in the cache - for example, just after dirtying a page. 1235 * dirty pages in the cache are not allowed. 1236 * 1237 * The page queues must be locked. 1238 * This routine may not block. 1239 */ 1240 void 1241 vm_page_unwire(m, activate) 1242 register vm_page_t m; 1243 int activate; 1244 { 1245 int s; 1246 1247 s = splvm(); 1248 1249 if (m->wire_count > 0) { 1250 m->wire_count--; 1251 if (m->wire_count == 0) { 1252 cnt.v_wire_count--; 1253 if (activate) { 1254 TAILQ_INSERT_TAIL(&vm_page_queue_active, m, pageq); 1255 m->queue = PQ_ACTIVE; 1256 (*vm_page_queues[PQ_ACTIVE].lcnt)++; 1257 cnt.v_active_count++; 1258 } else { 1259 TAILQ_INSERT_TAIL(&vm_page_queue_inactive, m, pageq); 1260 m->queue = PQ_INACTIVE; 1261 (*vm_page_queues[PQ_INACTIVE].lcnt)++; 1262 cnt.v_inactive_count++; 1263 } 1264 } 1265 } else { 1266 #if !defined(MAX_PERF) 1267 panic("vm_page_unwire: invalid wire count: %d\n", m->wire_count); 1268 #endif 1269 } 1270 splx(s); 1271 } 1272 1273 1274 /* 1275 * Move the specified page to the inactive queue. If the page has 1276 * any associated swap, the swap is deallocated. 1277 * 1278 * This routine may not block. 1279 */ 1280 void 1281 vm_page_deactivate(m) 1282 register vm_page_t m; 1283 { 1284 int s; 1285 1286 /* 1287 * Ignore if already inactive. 1288 */ 1289 if (m->queue == PQ_INACTIVE) 1290 return; 1291 1292 s = splvm(); 1293 if (m->wire_count == 0) { 1294 if ((m->queue - m->pc) == PQ_CACHE) 1295 cnt.v_reactivated++; 1296 vm_page_unqueue(m); 1297 TAILQ_INSERT_TAIL(&vm_page_queue_inactive, m, pageq); 1298 m->queue = PQ_INACTIVE; 1299 ++(*vm_page_queues[PQ_INACTIVE].lcnt); 1300 cnt.v_inactive_count++; 1301 } 1302 splx(s); 1303 } 1304 1305 /* 1306 * vm_page_cache 1307 * 1308 * Put the specified page onto the page cache queue (if appropriate). 1309 * 1310 * This routine may not block. 1311 */ 1312 void 1313 vm_page_cache(m) 1314 register vm_page_t m; 1315 { 1316 int s; 1317 1318 #if !defined(MAX_PERF) 1319 if ((m->flags & PG_BUSY) || m->busy || m->wire_count) { 1320 printf("vm_page_cache: attempting to cache busy page\n"); 1321 return; 1322 } 1323 #endif 1324 if ((m->queue - m->pc) == PQ_CACHE) 1325 return; 1326 1327 /* 1328 * Remove all pmaps and indicate that the page is not 1329 * writeable or mapped. 1330 */ 1331 1332 vm_page_protect(m, VM_PROT_NONE); 1333 #if !defined(MAX_PERF) 1334 if (m->dirty != 0) { 1335 panic("vm_page_cache: caching a dirty page, pindex: %d", m->pindex); 1336 } 1337 #endif 1338 s = splvm(); 1339 vm_page_unqueue_nowakeup(m); 1340 m->queue = PQ_CACHE + m->pc; 1341 (*vm_page_queues[m->queue].lcnt)++; 1342 TAILQ_INSERT_TAIL(vm_page_queues[m->queue].pl, m, pageq); 1343 cnt.v_cache_count++; 1344 vm_page_free_wakeup(); 1345 splx(s); 1346 } 1347 1348 /* 1349 * Grab a page, waiting until we are waken up due to the page 1350 * changing state. We keep on waiting, if the page continues 1351 * to be in the object. If the page doesn't exist, allocate it. 1352 * 1353 * This routine may block. 1354 */ 1355 vm_page_t 1356 vm_page_grab(object, pindex, allocflags) 1357 vm_object_t object; 1358 vm_pindex_t pindex; 1359 int allocflags; 1360 { 1361 1362 vm_page_t m; 1363 int s, generation; 1364 1365 retrylookup: 1366 if ((m = vm_page_lookup(object, pindex)) != NULL) { 1367 if (m->busy || (m->flags & PG_BUSY)) { 1368 generation = object->generation; 1369 1370 s = splvm(); 1371 while ((object->generation == generation) && 1372 (m->busy || (m->flags & PG_BUSY))) { 1373 vm_page_flag_set(m, PG_WANTED | PG_REFERENCED); 1374 tsleep(m, PVM, "pgrbwt", 0); 1375 if ((allocflags & VM_ALLOC_RETRY) == 0) { 1376 splx(s); 1377 return NULL; 1378 } 1379 } 1380 splx(s); 1381 goto retrylookup; 1382 } else { 1383 vm_page_busy(m); 1384 return m; 1385 } 1386 } 1387 1388 m = vm_page_alloc(object, pindex, allocflags & ~VM_ALLOC_RETRY); 1389 if (m == NULL) { 1390 VM_WAIT; 1391 if ((allocflags & VM_ALLOC_RETRY) == 0) 1392 return NULL; 1393 goto retrylookup; 1394 } 1395 1396 return m; 1397 } 1398 1399 /* 1400 * Mapping function for valid bits or for dirty bits in 1401 * a page. May not block. 1402 * 1403 * Inputs are required to range within a page. 1404 */ 1405 1406 __inline int 1407 vm_page_bits(int base, int size) 1408 { 1409 int first_bit; 1410 int last_bit; 1411 1412 KASSERT( 1413 base + size <= PAGE_SIZE, 1414 ("vm_page_bits: illegal base/size %d/%d", base, size) 1415 ); 1416 1417 if (size == 0) /* handle degenerate case */ 1418 return(0); 1419 1420 first_bit = base >> DEV_BSHIFT; 1421 last_bit = (base + size - 1) >> DEV_BSHIFT; 1422 1423 return ((2 << last_bit) - (1 << first_bit)); 1424 } 1425 1426 /* 1427 * vm_page_set_validclean: 1428 * 1429 * Sets portions of a page valid and clean. The arguments are expected 1430 * to be DEV_BSIZE aligned but if they aren't the bitmap is inclusive 1431 * of any partial chunks touched by the range. The invalid portion of 1432 * such chunks will be zero'd. 1433 * 1434 * This routine may not block. 1435 * 1436 * (base + size) must be less then or equal to PAGE_SIZE. 1437 */ 1438 void 1439 vm_page_set_validclean(m, base, size) 1440 vm_page_t m; 1441 int base; 1442 int size; 1443 { 1444 int pagebits; 1445 int frag; 1446 int endoff; 1447 1448 if (size == 0) /* handle degenerate case */ 1449 return; 1450 1451 /* 1452 * If the base is not DEV_BSIZE aligned and the valid 1453 * bit is clear, we have to zero out a portion of the 1454 * first block. 1455 */ 1456 1457 if ((frag = base & ~(DEV_BSIZE - 1)) != base && 1458 (m->valid & (1 << (base >> DEV_BSHIFT))) == 0 1459 ) { 1460 pmap_zero_page_area( 1461 VM_PAGE_TO_PHYS(m), 1462 frag, 1463 base - frag 1464 ); 1465 } 1466 1467 /* 1468 * If the ending offset is not DEV_BSIZE aligned and the 1469 * valid bit is clear, we have to zero out a portion of 1470 * the last block. 1471 */ 1472 1473 endoff = base + size; 1474 1475 if ((frag = endoff & ~(DEV_BSIZE - 1)) != endoff && 1476 (m->valid & (1 << (endoff >> DEV_BSHIFT))) == 0 1477 ) { 1478 pmap_zero_page_area( 1479 VM_PAGE_TO_PHYS(m), 1480 endoff, 1481 DEV_BSIZE - (endoff & (DEV_BSIZE - 1)) 1482 ); 1483 } 1484 1485 /* 1486 * Set valid, clear dirty bits. If validating the entire 1487 * page we can safely clear the pmap modify bit. 1488 */ 1489 1490 pagebits = vm_page_bits(base, size); 1491 m->valid |= pagebits; 1492 m->dirty &= ~pagebits; 1493 1494 if (base == 0 && size == PAGE_SIZE) 1495 pmap_clear_modify(VM_PAGE_TO_PHYS(m)); 1496 } 1497 1498 #if 0 1499 1500 void 1501 vm_page_set_dirty(m, base, size) 1502 vm_page_t m; 1503 int base; 1504 int size; 1505 { 1506 m->dirty |= vm_page_bits(base, size); 1507 } 1508 1509 #endif 1510 1511 void 1512 vm_page_clear_dirty(m, base, size) 1513 vm_page_t m; 1514 int base; 1515 int size; 1516 { 1517 m->dirty &= ~vm_page_bits(base, size); 1518 } 1519 1520 /* 1521 * vm_page_set_invalid: 1522 * 1523 * Invalidates DEV_BSIZE'd chunks within a page. Both the 1524 * valid and dirty bits for the effected areas are cleared. 1525 * 1526 * May not block. 1527 */ 1528 void 1529 vm_page_set_invalid(m, base, size) 1530 vm_page_t m; 1531 int base; 1532 int size; 1533 { 1534 int bits; 1535 1536 bits = vm_page_bits(base, size); 1537 m->valid &= ~bits; 1538 m->dirty &= ~bits; 1539 m->object->generation++; 1540 } 1541 1542 /* 1543 * vm_page_zero_invalid() 1544 * 1545 * The kernel assumes that the invalid portions of a page contain 1546 * garbage, but such pages can be mapped into memory by user code. 1547 * When this occurs, we must zero out the non-valid portions of the 1548 * page so user code sees what it expects. 1549 * 1550 * Pages are most often semi-valid when the end of a file is mapped 1551 * into memory and the file's size is not page aligned. 1552 */ 1553 1554 void 1555 vm_page_zero_invalid(vm_page_t m, boolean_t setvalid) 1556 { 1557 int b; 1558 int i; 1559 1560 /* 1561 * Scan the valid bits looking for invalid sections that 1562 * must be zerod. Invalid sub-DEV_BSIZE'd areas ( where the 1563 * valid bit may be set ) have already been zerod by 1564 * vm_page_set_validclean(). 1565 */ 1566 1567 for (b = i = 0; i <= PAGE_SIZE / DEV_BSIZE; ++i) { 1568 if (i == (PAGE_SIZE / DEV_BSIZE) || 1569 (m->valid & (1 << i)) 1570 ) { 1571 if (i > b) { 1572 pmap_zero_page_area( 1573 VM_PAGE_TO_PHYS(m), 1574 b << DEV_BSHIFT, 1575 (i - b) << DEV_BSHIFT 1576 ); 1577 } 1578 b = i + 1; 1579 } 1580 } 1581 1582 /* 1583 * setvalid is TRUE when we can safely set the zero'd areas 1584 * as being valid. We can do this if there are no cache consistancy 1585 * issues. e.g. it is ok to do with UFS, but not ok to do with NFS. 1586 */ 1587 1588 if (setvalid) 1589 m->valid = VM_PAGE_BITS_ALL; 1590 } 1591 1592 /* 1593 * vm_page_is_valid: 1594 * 1595 * Is (partial) page valid? Note that the case where size == 0 1596 * will return FALSE in the degenerate case where the page is 1597 * entirely invalid, and TRUE otherwise. 1598 * 1599 * May not block. 1600 */ 1601 1602 int 1603 vm_page_is_valid(m, base, size) 1604 vm_page_t m; 1605 int base; 1606 int size; 1607 { 1608 int bits = vm_page_bits(base, size); 1609 1610 if (m->valid && ((m->valid & bits) == bits)) 1611 return 1; 1612 else 1613 return 0; 1614 } 1615 1616 /* 1617 * update dirty bits from pmap/mmu. May not block. 1618 */ 1619 1620 void 1621 vm_page_test_dirty(m) 1622 vm_page_t m; 1623 { 1624 if ((m->dirty != VM_PAGE_BITS_ALL) && 1625 pmap_is_modified(VM_PAGE_TO_PHYS(m))) { 1626 vm_page_dirty(m); 1627 } 1628 } 1629 1630 /* 1631 * This interface is for merging with malloc() someday. 1632 * Even if we never implement compaction so that contiguous allocation 1633 * works after initialization time, malloc()'s data structures are good 1634 * for statistics and for allocations of less than a page. 1635 */ 1636 void * 1637 contigmalloc1(size, type, flags, low, high, alignment, boundary, map) 1638 unsigned long size; /* should be size_t here and for malloc() */ 1639 struct malloc_type *type; 1640 int flags; 1641 unsigned long low; 1642 unsigned long high; 1643 unsigned long alignment; 1644 unsigned long boundary; 1645 vm_map_t map; 1646 { 1647 int i, s, start; 1648 vm_offset_t addr, phys, tmp_addr; 1649 int pass; 1650 vm_page_t pga = vm_page_array; 1651 1652 size = round_page(size); 1653 #if !defined(MAX_PERF) 1654 if (size == 0) 1655 panic("contigmalloc1: size must not be 0"); 1656 if ((alignment & (alignment - 1)) != 0) 1657 panic("contigmalloc1: alignment must be a power of 2"); 1658 if ((boundary & (boundary - 1)) != 0) 1659 panic("contigmalloc1: boundary must be a power of 2"); 1660 #endif 1661 1662 start = 0; 1663 for (pass = 0; pass <= 1; pass++) { 1664 s = splvm(); 1665 again: 1666 /* 1667 * Find first page in array that is free, within range, aligned, and 1668 * such that the boundary won't be crossed. 1669 */ 1670 for (i = start; i < cnt.v_page_count; i++) { 1671 int pqtype; 1672 phys = VM_PAGE_TO_PHYS(&pga[i]); 1673 pqtype = pga[i].queue - pga[i].pc; 1674 if (((pqtype == PQ_FREE) || (pqtype == PQ_CACHE)) && 1675 (phys >= low) && (phys < high) && 1676 ((phys & (alignment - 1)) == 0) && 1677 (((phys ^ (phys + size - 1)) & ~(boundary - 1)) == 0)) 1678 break; 1679 } 1680 1681 /* 1682 * If the above failed or we will exceed the upper bound, fail. 1683 */ 1684 if ((i == cnt.v_page_count) || 1685 ((VM_PAGE_TO_PHYS(&pga[i]) + size) > high)) { 1686 vm_page_t m, next; 1687 1688 again1: 1689 for (m = TAILQ_FIRST(&vm_page_queue_inactive); 1690 m != NULL; 1691 m = next) { 1692 1693 if (m->queue != PQ_INACTIVE) { 1694 break; 1695 } 1696 1697 next = TAILQ_NEXT(m, pageq); 1698 if (vm_page_sleep_busy(m, TRUE, "vpctw0")) 1699 goto again1; 1700 vm_page_test_dirty(m); 1701 if (m->dirty) { 1702 if (m->object->type == OBJT_VNODE) { 1703 vn_lock(m->object->handle, LK_EXCLUSIVE | LK_RETRY, curproc); 1704 vm_object_page_clean(m->object, 0, 0, OBJPC_SYNC); 1705 VOP_UNLOCK(m->object->handle, 0, curproc); 1706 goto again1; 1707 } else if (m->object->type == OBJT_SWAP || 1708 m->object->type == OBJT_DEFAULT) { 1709 vm_pageout_flush(&m, 1, 0); 1710 goto again1; 1711 } 1712 } 1713 if ((m->dirty == 0) && (m->busy == 0) && (m->hold_count == 0)) 1714 vm_page_cache(m); 1715 } 1716 1717 for (m = TAILQ_FIRST(&vm_page_queue_active); 1718 m != NULL; 1719 m = next) { 1720 1721 if (m->queue != PQ_ACTIVE) { 1722 break; 1723 } 1724 1725 next = TAILQ_NEXT(m, pageq); 1726 if (vm_page_sleep_busy(m, TRUE, "vpctw1")) 1727 goto again1; 1728 vm_page_test_dirty(m); 1729 if (m->dirty) { 1730 if (m->object->type == OBJT_VNODE) { 1731 vn_lock(m->object->handle, LK_EXCLUSIVE | LK_RETRY, curproc); 1732 vm_object_page_clean(m->object, 0, 0, OBJPC_SYNC); 1733 VOP_UNLOCK(m->object->handle, 0, curproc); 1734 goto again1; 1735 } else if (m->object->type == OBJT_SWAP || 1736 m->object->type == OBJT_DEFAULT) { 1737 vm_pageout_flush(&m, 1, 0); 1738 goto again1; 1739 } 1740 } 1741 if ((m->dirty == 0) && (m->busy == 0) && (m->hold_count == 0)) 1742 vm_page_cache(m); 1743 } 1744 1745 splx(s); 1746 continue; 1747 } 1748 start = i; 1749 1750 /* 1751 * Check successive pages for contiguous and free. 1752 */ 1753 for (i = start + 1; i < (start + size / PAGE_SIZE); i++) { 1754 int pqtype; 1755 pqtype = pga[i].queue - pga[i].pc; 1756 if ((VM_PAGE_TO_PHYS(&pga[i]) != 1757 (VM_PAGE_TO_PHYS(&pga[i - 1]) + PAGE_SIZE)) || 1758 ((pqtype != PQ_FREE) && (pqtype != PQ_CACHE))) { 1759 start++; 1760 goto again; 1761 } 1762 } 1763 1764 for (i = start; i < (start + size / PAGE_SIZE); i++) { 1765 int pqtype; 1766 vm_page_t m = &pga[i]; 1767 1768 pqtype = m->queue - m->pc; 1769 if (pqtype == PQ_CACHE) { 1770 vm_page_busy(m); 1771 vm_page_free(m); 1772 } 1773 1774 TAILQ_REMOVE(vm_page_queues[m->queue].pl, m, pageq); 1775 (*vm_page_queues[m->queue].lcnt)--; 1776 cnt.v_free_count--; 1777 m->valid = VM_PAGE_BITS_ALL; 1778 m->flags = 0; 1779 m->dirty = 0; 1780 m->wire_count = 0; 1781 m->busy = 0; 1782 m->queue = PQ_NONE; 1783 m->object = NULL; 1784 vm_page_wire(m); 1785 } 1786 1787 /* 1788 * We've found a contiguous chunk that meets are requirements. 1789 * Allocate kernel VM, unfree and assign the physical pages to it and 1790 * return kernel VM pointer. 1791 */ 1792 tmp_addr = addr = kmem_alloc_pageable(map, size); 1793 if (addr == 0) { 1794 /* 1795 * XXX We almost never run out of kernel virtual 1796 * space, so we don't make the allocated memory 1797 * above available. 1798 */ 1799 splx(s); 1800 return (NULL); 1801 } 1802 1803 for (i = start; i < (start + size / PAGE_SIZE); i++) { 1804 vm_page_t m = &pga[i]; 1805 vm_page_insert(m, kernel_object, 1806 OFF_TO_IDX(tmp_addr - VM_MIN_KERNEL_ADDRESS)); 1807 pmap_kenter(tmp_addr, VM_PAGE_TO_PHYS(m)); 1808 tmp_addr += PAGE_SIZE; 1809 } 1810 1811 splx(s); 1812 return ((void *)addr); 1813 } 1814 return NULL; 1815 } 1816 1817 void * 1818 contigmalloc(size, type, flags, low, high, alignment, boundary) 1819 unsigned long size; /* should be size_t here and for malloc() */ 1820 struct malloc_type *type; 1821 int flags; 1822 unsigned long low; 1823 unsigned long high; 1824 unsigned long alignment; 1825 unsigned long boundary; 1826 { 1827 return contigmalloc1(size, type, flags, low, high, alignment, boundary, 1828 kernel_map); 1829 } 1830 1831 vm_offset_t 1832 vm_page_alloc_contig(size, low, high, alignment) 1833 vm_offset_t size; 1834 vm_offset_t low; 1835 vm_offset_t high; 1836 vm_offset_t alignment; 1837 { 1838 return ((vm_offset_t)contigmalloc1(size, M_DEVBUF, M_NOWAIT, low, high, 1839 alignment, 0ul, kernel_map)); 1840 } 1841 1842 #include "opt_ddb.h" 1843 #ifdef DDB 1844 #include <sys/kernel.h> 1845 1846 #include <ddb/ddb.h> 1847 1848 DB_SHOW_COMMAND(page, vm_page_print_page_info) 1849 { 1850 db_printf("cnt.v_free_count: %d\n", cnt.v_free_count); 1851 db_printf("cnt.v_cache_count: %d\n", cnt.v_cache_count); 1852 db_printf("cnt.v_inactive_count: %d\n", cnt.v_inactive_count); 1853 db_printf("cnt.v_active_count: %d\n", cnt.v_active_count); 1854 db_printf("cnt.v_wire_count: %d\n", cnt.v_wire_count); 1855 db_printf("cnt.v_free_reserved: %d\n", cnt.v_free_reserved); 1856 db_printf("cnt.v_free_min: %d\n", cnt.v_free_min); 1857 db_printf("cnt.v_free_target: %d\n", cnt.v_free_target); 1858 db_printf("cnt.v_cache_min: %d\n", cnt.v_cache_min); 1859 db_printf("cnt.v_inactive_target: %d\n", cnt.v_inactive_target); 1860 } 1861 1862 DB_SHOW_COMMAND(pageq, vm_page_print_pageq_info) 1863 { 1864 int i; 1865 db_printf("PQ_FREE:"); 1866 for(i=0;i<PQ_L2_SIZE;i++) { 1867 db_printf(" %d", *vm_page_queues[PQ_FREE + i].lcnt); 1868 } 1869 db_printf("\n"); 1870 1871 db_printf("PQ_CACHE:"); 1872 for(i=0;i<PQ_L2_SIZE;i++) { 1873 db_printf(" %d", *vm_page_queues[PQ_CACHE + i].lcnt); 1874 } 1875 db_printf("\n"); 1876 1877 db_printf("PQ_ACTIVE: %d, PQ_INACTIVE: %d\n", 1878 *vm_page_queues[PQ_ACTIVE].lcnt, 1879 *vm_page_queues[PQ_INACTIVE].lcnt); 1880 } 1881 #endif /* DDB */ 1882