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: src/sys/vm/vm_page.c,v 1.147.2.18 2002/03/10 05:03:19 alc Exp $ 38 * $DragonFly: src/sys/vm/vm_page.c,v 1.7 2003/07/19 21:14:53 dillon Exp $ 39 */ 40 41 /* 42 * Copyright (c) 1987, 1990 Carnegie-Mellon University. 43 * All rights reserved. 44 * 45 * Authors: Avadis Tevanian, Jr., Michael Wayne Young 46 * 47 * Permission to use, copy, modify and distribute this software and 48 * its documentation is hereby granted, provided that both the copyright 49 * notice and this permission notice appear in all copies of the 50 * software, derivative works or modified versions, and any portions 51 * thereof, and that both notices appear in supporting documentation. 52 * 53 * CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS" 54 * CONDITION. CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND 55 * FOR ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE. 56 * 57 * Carnegie Mellon requests users of this software to return to 58 * 59 * Software Distribution Coordinator or Software.Distribution@CS.CMU.EDU 60 * School of Computer Science 61 * Carnegie Mellon University 62 * Pittsburgh PA 15213-3890 63 * 64 * any improvements or extensions that they make and grant Carnegie the 65 * rights to redistribute these changes. 66 */ 67 68 /* 69 * Resident memory management module. 70 */ 71 72 #include <sys/param.h> 73 #include <sys/systm.h> 74 #include <sys/malloc.h> 75 #include <sys/proc.h> 76 #include <sys/vmmeter.h> 77 #include <sys/vnode.h> 78 79 #include <vm/vm.h> 80 #include <vm/vm_param.h> 81 #include <sys/lock.h> 82 #include <vm/vm_kern.h> 83 #include <vm/pmap.h> 84 #include <vm/vm_map.h> 85 #include <vm/vm_object.h> 86 #include <vm/vm_page.h> 87 #include <vm/vm_pageout.h> 88 #include <vm/vm_pager.h> 89 #include <vm/vm_extern.h> 90 #include <vm/vm_page2.h> 91 92 static void vm_page_queue_init (void); 93 static vm_page_t vm_page_select_cache (vm_object_t, vm_pindex_t); 94 95 /* 96 * Associated with page of user-allocatable memory is a 97 * page structure. 98 */ 99 100 static struct vm_page **vm_page_buckets; /* Array of buckets */ 101 static int vm_page_bucket_count; /* How big is array? */ 102 static int vm_page_hash_mask; /* Mask for hash function */ 103 static volatile int vm_page_bucket_generation; 104 105 struct vpgqueues vm_page_queues[PQ_COUNT]; 106 107 static void 108 vm_page_queue_init(void) { 109 int i; 110 111 for(i=0;i<PQ_L2_SIZE;i++) { 112 vm_page_queues[PQ_FREE+i].cnt = &vmstats.v_free_count; 113 } 114 vm_page_queues[PQ_INACTIVE].cnt = &vmstats.v_inactive_count; 115 116 vm_page_queues[PQ_ACTIVE].cnt = &vmstats.v_active_count; 117 vm_page_queues[PQ_HOLD].cnt = &vmstats.v_active_count; 118 for(i=0;i<PQ_L2_SIZE;i++) { 119 vm_page_queues[PQ_CACHE+i].cnt = &vmstats.v_cache_count; 120 } 121 for(i=0;i<PQ_COUNT;i++) { 122 TAILQ_INIT(&vm_page_queues[i].pl); 123 } 124 } 125 126 vm_page_t vm_page_array = 0; 127 int vm_page_array_size = 0; 128 long first_page = 0; 129 int vm_page_zero_count = 0; 130 131 static __inline int vm_page_hash (vm_object_t object, vm_pindex_t pindex); 132 static void vm_page_free_wakeup (void); 133 134 /* 135 * vm_set_page_size: 136 * 137 * Sets the page size, perhaps based upon the memory 138 * size. Must be called before any use of page-size 139 * dependent functions. 140 */ 141 void 142 vm_set_page_size(void) 143 { 144 if (vmstats.v_page_size == 0) 145 vmstats.v_page_size = PAGE_SIZE; 146 if (((vmstats.v_page_size - 1) & vmstats.v_page_size) != 0) 147 panic("vm_set_page_size: page size not a power of two"); 148 } 149 150 /* 151 * vm_add_new_page: 152 * 153 * Add a new page to the freelist for use by the system. 154 * Must be called at splhigh(). 155 */ 156 vm_page_t 157 vm_add_new_page(vm_offset_t pa) 158 { 159 vm_page_t m; 160 161 ++vmstats.v_page_count; 162 ++vmstats.v_free_count; 163 m = PHYS_TO_VM_PAGE(pa); 164 m->phys_addr = pa; 165 m->flags = 0; 166 m->pc = (pa >> PAGE_SHIFT) & PQ_L2_MASK; 167 m->queue = m->pc + PQ_FREE; 168 TAILQ_INSERT_HEAD(&vm_page_queues[m->queue].pl, m, pageq); 169 vm_page_queues[m->queue].lcnt++; 170 return (m); 171 } 172 173 /* 174 * vm_page_startup: 175 * 176 * Initializes the resident memory module. 177 * 178 * Allocates memory for the page cells, and 179 * for the object/offset-to-page hash table headers. 180 * Each page cell is initialized and placed on the free list. 181 */ 182 183 vm_offset_t 184 vm_page_startup(vm_offset_t starta, vm_offset_t enda, vm_offset_t vaddr) 185 { 186 vm_offset_t mapped; 187 struct vm_page **bucket; 188 vm_size_t npages, page_range; 189 vm_offset_t new_end; 190 int i; 191 vm_offset_t pa; 192 int nblocks; 193 vm_offset_t last_pa; 194 195 /* the biggest memory array is the second group of pages */ 196 vm_offset_t end; 197 vm_offset_t biggestone, biggestsize; 198 199 vm_offset_t total; 200 201 total = 0; 202 biggestsize = 0; 203 biggestone = 0; 204 nblocks = 0; 205 vaddr = round_page(vaddr); 206 207 for (i = 0; phys_avail[i + 1]; i += 2) { 208 phys_avail[i] = round_page(phys_avail[i]); 209 phys_avail[i + 1] = trunc_page(phys_avail[i + 1]); 210 } 211 212 for (i = 0; phys_avail[i + 1]; i += 2) { 213 int size = phys_avail[i + 1] - phys_avail[i]; 214 215 if (size > biggestsize) { 216 biggestone = i; 217 biggestsize = size; 218 } 219 ++nblocks; 220 total += size; 221 } 222 223 end = phys_avail[biggestone+1]; 224 225 /* 226 * Initialize the queue headers for the free queue, the active queue 227 * and the inactive queue. 228 */ 229 230 vm_page_queue_init(); 231 232 /* 233 * Allocate (and initialize) the hash table buckets. 234 * 235 * The number of buckets MUST BE a power of 2, and the actual value is 236 * the next power of 2 greater than the number of physical pages in 237 * the system. 238 * 239 * We make the hash table approximately 2x the number of pages to 240 * reduce the chain length. This is about the same size using the 241 * singly-linked list as the 1x hash table we were using before 242 * using TAILQ but the chain length will be smaller. 243 * 244 * Note: This computation can be tweaked if desired. 245 */ 246 vm_page_buckets = (struct vm_page **)vaddr; 247 bucket = vm_page_buckets; 248 if (vm_page_bucket_count == 0) { 249 vm_page_bucket_count = 1; 250 while (vm_page_bucket_count < atop(total)) 251 vm_page_bucket_count <<= 1; 252 } 253 vm_page_bucket_count <<= 1; 254 vm_page_hash_mask = vm_page_bucket_count - 1; 255 256 /* 257 * Validate these addresses. 258 */ 259 new_end = end - vm_page_bucket_count * sizeof(struct vm_page *); 260 new_end = trunc_page(new_end); 261 mapped = round_page(vaddr); 262 vaddr = pmap_map(mapped, new_end, end, 263 VM_PROT_READ | VM_PROT_WRITE); 264 vaddr = round_page(vaddr); 265 bzero((caddr_t) mapped, vaddr - mapped); 266 267 for (i = 0; i < vm_page_bucket_count; i++) { 268 *bucket = NULL; 269 bucket++; 270 } 271 272 /* 273 * Compute the number of pages of memory that will be available for 274 * use (taking into account the overhead of a page structure per 275 * page). 276 */ 277 278 first_page = phys_avail[0] / PAGE_SIZE; 279 280 page_range = phys_avail[(nblocks - 1) * 2 + 1] / PAGE_SIZE - first_page; 281 npages = (total - (page_range * sizeof(struct vm_page)) - 282 (end - new_end)) / PAGE_SIZE; 283 284 end = new_end; 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 */ 295 296 new_end = trunc_page(end - page_range * sizeof(struct vm_page)); 297 mapped = pmap_map(mapped, new_end, end, 298 VM_PROT_READ | VM_PROT_WRITE); 299 300 /* 301 * Clear all of the page structures 302 */ 303 bzero((caddr_t) vm_page_array, page_range * sizeof(struct vm_page)); 304 vm_page_array_size = page_range; 305 306 /* 307 * Construct the free queue(s) in descending order (by physical 308 * address) so that the first 16MB of physical memory is allocated 309 * last rather than first. On large-memory machines, this avoids 310 * the exhaustion of low physical memory before isa_dmainit has run. 311 */ 312 vmstats.v_page_count = 0; 313 vmstats.v_free_count = 0; 314 for (i = 0; phys_avail[i + 1] && npages > 0; i += 2) { 315 pa = phys_avail[i]; 316 if (i == biggestone) 317 last_pa = new_end; 318 else 319 last_pa = phys_avail[i + 1]; 320 while (pa < last_pa && npages-- > 0) { 321 vm_add_new_page(pa); 322 pa += PAGE_SIZE; 323 } 324 } 325 return (mapped); 326 } 327 328 /* 329 * vm_page_hash: 330 * 331 * Distributes the object/offset key pair among hash buckets. 332 * 333 * NOTE: This macro depends on vm_page_bucket_count being a power of 2. 334 * This routine may not block. 335 * 336 * We try to randomize the hash based on the object to spread the pages 337 * out in the hash table without it costing us too much. 338 */ 339 static __inline int 340 vm_page_hash(vm_object_t object, vm_pindex_t pindex) 341 { 342 int i = ((uintptr_t)object + pindex) ^ object->hash_rand; 343 344 return(i & vm_page_hash_mask); 345 } 346 347 void 348 vm_page_unhold(vm_page_t mem) 349 { 350 --mem->hold_count; 351 KASSERT(mem->hold_count >= 0, ("vm_page_unhold: hold count < 0!!!")); 352 if (mem->hold_count == 0 && mem->queue == PQ_HOLD) 353 vm_page_free_toq(mem); 354 } 355 356 /* 357 * vm_page_insert: [ internal use only ] 358 * 359 * Inserts the given mem entry into the object and object list. 360 * 361 * The pagetables are not updated but will presumably fault the page 362 * in if necessary, or if a kernel page the caller will at some point 363 * enter the page into the kernel's pmap. We are not allowed to block 364 * here so we *can't* do this anyway. 365 * 366 * The object and page must be locked, and must be splhigh. 367 * This routine may not block. 368 */ 369 370 void 371 vm_page_insert(vm_page_t m, vm_object_t object, vm_pindex_t pindex) 372 { 373 struct vm_page **bucket; 374 375 if (m->object != NULL) 376 panic("vm_page_insert: already inserted"); 377 378 /* 379 * Record the object/offset pair in this page 380 */ 381 382 m->object = object; 383 m->pindex = pindex; 384 385 /* 386 * Insert it into the object_object/offset hash table 387 */ 388 389 bucket = &vm_page_buckets[vm_page_hash(object, pindex)]; 390 m->hnext = *bucket; 391 *bucket = m; 392 vm_page_bucket_generation++; 393 394 /* 395 * Now link into the object's list of backed pages. 396 */ 397 398 TAILQ_INSERT_TAIL(&object->memq, m, listq); 399 object->generation++; 400 401 /* 402 * show that the object has one more resident page. 403 */ 404 405 object->resident_page_count++; 406 407 /* 408 * Since we are inserting a new and possibly dirty page, 409 * update the object's OBJ_WRITEABLE and OBJ_MIGHTBEDIRTY flags. 410 */ 411 if (m->flags & PG_WRITEABLE) 412 vm_object_set_writeable_dirty(object); 413 } 414 415 /* 416 * vm_page_remove: 417 * NOTE: used by device pager as well -wfj 418 * 419 * Removes the given mem entry from the object/offset-page 420 * table and the object page list, but do not invalidate/terminate 421 * the backing store. 422 * 423 * The object and page must be locked, and at splhigh. 424 * The underlying pmap entry (if any) is NOT removed here. 425 * This routine may not block. 426 */ 427 428 void 429 vm_page_remove(vm_page_t m) 430 { 431 vm_object_t object; 432 433 if (m->object == NULL) 434 return; 435 436 if ((m->flags & PG_BUSY) == 0) { 437 panic("vm_page_remove: page not busy"); 438 } 439 440 /* 441 * Basically destroy the page. 442 */ 443 444 vm_page_wakeup(m); 445 446 object = m->object; 447 448 /* 449 * Remove from the object_object/offset hash table. The object 450 * must be on the hash queue, we will panic if it isn't 451 * 452 * Note: we must NULL-out m->hnext to prevent loops in detached 453 * buffers with vm_page_lookup(). 454 */ 455 456 { 457 struct vm_page **bucket; 458 459 bucket = &vm_page_buckets[vm_page_hash(m->object, m->pindex)]; 460 while (*bucket != m) { 461 if (*bucket == NULL) 462 panic("vm_page_remove(): page not found in hash"); 463 bucket = &(*bucket)->hnext; 464 } 465 *bucket = m->hnext; 466 m->hnext = NULL; 467 vm_page_bucket_generation++; 468 } 469 470 /* 471 * Now remove from the object's list of backed pages. 472 */ 473 474 TAILQ_REMOVE(&object->memq, m, listq); 475 476 /* 477 * And show that the object has one fewer resident page. 478 */ 479 480 object->resident_page_count--; 481 object->generation++; 482 483 m->object = NULL; 484 } 485 486 /* 487 * vm_page_lookup: 488 * 489 * Returns the page associated with the object/offset 490 * pair specified; if none is found, NULL is returned. 491 * 492 * NOTE: the code below does not lock. It will operate properly if 493 * an interrupt makes a change, but the generation algorithm will not 494 * operate properly in an SMP environment where both cpu's are able to run 495 * kernel code simultaneously. 496 * 497 * The object must be locked. No side effects. 498 * This routine may not block. 499 * This is a critical path routine 500 */ 501 502 vm_page_t 503 vm_page_lookup(vm_object_t object, vm_pindex_t pindex) 504 { 505 vm_page_t m; 506 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(vm_page_t m, vm_object_t new_object, vm_pindex_t new_pindex) 554 { 555 int s; 556 557 s = splvm(); 558 vm_page_remove(m); 559 vm_page_insert(m, new_object, new_pindex); 560 if (m->queue - m->pc == PQ_CACHE) 561 vm_page_deactivate(m); 562 vm_page_dirty(m); 563 splx(s); 564 } 565 566 /* 567 * vm_page_unqueue_nowakeup: 568 * 569 * vm_page_unqueue() without any wakeup 570 * 571 * This routine must be called at splhigh(). 572 * This routine may not block. 573 */ 574 575 void 576 vm_page_unqueue_nowakeup(vm_page_t m) 577 { 578 int queue = m->queue; 579 struct vpgqueues *pq; 580 if (queue != PQ_NONE) { 581 pq = &vm_page_queues[queue]; 582 m->queue = PQ_NONE; 583 TAILQ_REMOVE(&pq->pl, m, pageq); 584 (*pq->cnt)--; 585 pq->lcnt--; 586 } 587 } 588 589 /* 590 * vm_page_unqueue: 591 * 592 * Remove a page from its queue. 593 * 594 * This routine must be called at splhigh(). 595 * This routine may not block. 596 */ 597 598 void 599 vm_page_unqueue(vm_page_t m) 600 { 601 int queue = m->queue; 602 struct vpgqueues *pq; 603 if (queue != PQ_NONE) { 604 m->queue = PQ_NONE; 605 pq = &vm_page_queues[queue]; 606 TAILQ_REMOVE(&pq->pl, m, pageq); 607 (*pq->cnt)--; 608 pq->lcnt--; 609 if ((queue - m->pc) == PQ_CACHE) { 610 if (vm_paging_needed()) 611 pagedaemon_wakeup(); 612 } 613 } 614 } 615 616 #if PQ_L2_SIZE > 1 617 618 /* 619 * vm_page_list_find: 620 * 621 * Find a page on the specified queue with color optimization. 622 * 623 * The page coloring optimization attempts to locate a page 624 * that does not overload other nearby pages in the object in 625 * the cpu's L1 or L2 caches. We need this optimization because 626 * cpu caches tend to be physical caches, while object spaces tend 627 * to be virtual. 628 * 629 * This routine must be called at splvm(). 630 * This routine may not block. 631 * 632 * This routine may only be called from the vm_page_list_find() macro 633 * in vm_page.h 634 */ 635 vm_page_t 636 _vm_page_list_find(int basequeue, int index) 637 { 638 int i; 639 vm_page_t m = NULL; 640 struct vpgqueues *pq; 641 642 pq = &vm_page_queues[basequeue]; 643 644 /* 645 * Note that for the first loop, index+i and index-i wind up at the 646 * same place. Even though this is not totally optimal, we've already 647 * blown it by missing the cache case so we do not care. 648 */ 649 650 for(i = PQ_L2_SIZE / 2; i > 0; --i) { 651 if ((m = TAILQ_FIRST(&pq[(index + i) & PQ_L2_MASK].pl)) != NULL) 652 break; 653 654 if ((m = TAILQ_FIRST(&pq[(index - i) & PQ_L2_MASK].pl)) != NULL) 655 break; 656 } 657 return(m); 658 } 659 660 #endif 661 662 /* 663 * vm_page_select_cache: 664 * 665 * Find a page on the cache queue with color optimization. As pages 666 * might be found, but not applicable, they are deactivated. This 667 * keeps us from using potentially busy cached pages. 668 * 669 * This routine must be called at splvm(). 670 * This routine may not block. 671 */ 672 vm_page_t 673 vm_page_select_cache(vm_object_t object, vm_pindex_t pindex) 674 { 675 vm_page_t m; 676 677 while (TRUE) { 678 m = vm_page_list_find( 679 PQ_CACHE, 680 (pindex + object->pg_color) & PQ_L2_MASK, 681 FALSE 682 ); 683 if (m && ((m->flags & (PG_BUSY|PG_UNMANAGED)) || m->busy || 684 m->hold_count || m->wire_count)) { 685 vm_page_deactivate(m); 686 continue; 687 } 688 return m; 689 } 690 } 691 692 /* 693 * vm_page_select_free: 694 * 695 * Find a free or zero page, with specified preference. We attempt to 696 * inline the nominal case and fall back to _vm_page_select_free() 697 * otherwise. 698 * 699 * This routine must be called at splvm(). 700 * This routine may not block. 701 */ 702 703 static __inline vm_page_t 704 vm_page_select_free(vm_object_t object, vm_pindex_t pindex, boolean_t prefer_zero) 705 { 706 vm_page_t m; 707 708 m = vm_page_list_find( 709 PQ_FREE, 710 (pindex + object->pg_color) & PQ_L2_MASK, 711 prefer_zero 712 ); 713 return(m); 714 } 715 716 /* 717 * vm_page_alloc: 718 * 719 * Allocate and return a memory cell associated 720 * with this VM object/offset pair. 721 * 722 * page_req classes: 723 * VM_ALLOC_NORMAL normal process request 724 * VM_ALLOC_SYSTEM system *really* needs a page 725 * VM_ALLOC_INTERRUPT interrupt time request 726 * VM_ALLOC_ZERO zero page 727 * 728 * Object must be locked. 729 * This routine may not block. 730 * 731 * Additional special handling is required when called from an 732 * interrupt (VM_ALLOC_INTERRUPT). We are not allowed to mess with 733 * the page cache in this case. 734 */ 735 736 vm_page_t 737 vm_page_alloc(vm_object_t object, vm_pindex_t pindex, int page_req) 738 { 739 vm_page_t m = NULL; 740 int s; 741 742 KASSERT(!vm_page_lookup(object, pindex), 743 ("vm_page_alloc: page already allocated")); 744 745 /* 746 * The pager is allowed to eat deeper into the free page list. 747 */ 748 749 if ((curthread == pagethread) && (page_req != VM_ALLOC_INTERRUPT)) { 750 page_req = VM_ALLOC_SYSTEM; 751 }; 752 753 s = splvm(); 754 755 loop: 756 if (vmstats.v_free_count > vmstats.v_free_reserved) { 757 /* 758 * Allocate from the free queue if there are plenty of pages 759 * in it. 760 */ 761 if (page_req == VM_ALLOC_ZERO) 762 m = vm_page_select_free(object, pindex, TRUE); 763 else 764 m = vm_page_select_free(object, pindex, FALSE); 765 } else if ( 766 (page_req == VM_ALLOC_SYSTEM && 767 vmstats.v_cache_count == 0 && 768 vmstats.v_free_count > vmstats.v_interrupt_free_min) || 769 (page_req == VM_ALLOC_INTERRUPT && vmstats.v_free_count > 0) 770 ) { 771 /* 772 * Interrupt or system, dig deeper into the free list. 773 */ 774 m = vm_page_select_free(object, pindex, FALSE); 775 } else if (page_req != VM_ALLOC_INTERRUPT) { 776 /* 777 * Allocatable from cache (non-interrupt only). On success, 778 * we must free the page and try again, thus ensuring that 779 * vmstats.v_*_free_min counters are replenished. 780 */ 781 m = vm_page_select_cache(object, pindex); 782 if (m == NULL) { 783 splx(s); 784 #if defined(DIAGNOSTIC) 785 if (vmstats.v_cache_count > 0) 786 printf("vm_page_alloc(NORMAL): missing pages on cache queue: %d\n", vmstats.v_cache_count); 787 #endif 788 vm_pageout_deficit++; 789 pagedaemon_wakeup(); 790 return (NULL); 791 } 792 KASSERT(m->dirty == 0, ("Found dirty cache page %p", m)); 793 vm_page_busy(m); 794 vm_page_protect(m, VM_PROT_NONE); 795 vm_page_free(m); 796 goto loop; 797 } else { 798 /* 799 * Not allocatable from cache from interrupt, give up. 800 */ 801 splx(s); 802 vm_pageout_deficit++; 803 pagedaemon_wakeup(); 804 return (NULL); 805 } 806 807 /* 808 * At this point we had better have found a good page. 809 */ 810 811 KASSERT( 812 m != NULL, 813 ("vm_page_alloc(): missing page on free queue\n") 814 ); 815 816 /* 817 * Remove from free queue 818 */ 819 820 vm_page_unqueue_nowakeup(m); 821 822 /* 823 * Initialize structure. Only the PG_ZERO flag is inherited. 824 */ 825 826 if (m->flags & PG_ZERO) { 827 vm_page_zero_count--; 828 m->flags = PG_ZERO | PG_BUSY; 829 } else { 830 m->flags = PG_BUSY; 831 } 832 m->wire_count = 0; 833 m->hold_count = 0; 834 m->act_count = 0; 835 m->busy = 0; 836 m->valid = 0; 837 KASSERT(m->dirty == 0, ("vm_page_alloc: free/cache page %p was dirty", m)); 838 839 /* 840 * vm_page_insert() is safe prior to the splx(). Note also that 841 * inserting a page here does not insert it into the pmap (which 842 * could cause us to block allocating memory). We cannot block 843 * anywhere. 844 */ 845 846 vm_page_insert(m, object, pindex); 847 848 /* 849 * Don't wakeup too often - wakeup the pageout daemon when 850 * we would be nearly out of memory. 851 */ 852 if (vm_paging_needed()) 853 pagedaemon_wakeup(); 854 855 splx(s); 856 857 return (m); 858 } 859 860 /* 861 * vm_wait: (also see VM_WAIT macro) 862 * 863 * Block until free pages are available for allocation 864 * - Called in various places before memory allocations. 865 */ 866 867 void 868 vm_wait(void) 869 { 870 int s; 871 872 s = splvm(); 873 if (curthread == pagethread) { 874 vm_pageout_pages_needed = 1; 875 tsleep(&vm_pageout_pages_needed, 0, "VMWait", 0); 876 } else { 877 if (!vm_pages_needed) { 878 vm_pages_needed = 1; 879 wakeup(&vm_pages_needed); 880 } 881 tsleep(&vmstats.v_free_count, 0, "vmwait", 0); 882 } 883 splx(s); 884 } 885 886 /* 887 * vm_waitpfault: (also see VM_WAITPFAULT macro) 888 * 889 * Block until free pages are available for allocation 890 * - Called only in vm_fault so that processes page faulting 891 * can be easily tracked. 892 * - Sleeps at a lower priority than vm_wait() so that vm_wait()ing 893 * processes will be able to grab memory first. Do not change 894 * this balance without careful testing first. 895 */ 896 897 void 898 vm_waitpfault(void) 899 { 900 int s; 901 902 s = splvm(); 903 if (!vm_pages_needed) { 904 vm_pages_needed = 1; 905 wakeup(&vm_pages_needed); 906 } 907 tsleep(&vmstats.v_free_count, 0, "pfault", 0); 908 splx(s); 909 } 910 911 /* 912 * vm_page_activate: 913 * 914 * Put the specified page on the active list (if appropriate). 915 * Ensure that act_count is at least ACT_INIT but do not otherwise 916 * mess with it. 917 * 918 * The page queues must be locked. 919 * This routine may not block. 920 */ 921 void 922 vm_page_activate(vm_page_t m) 923 { 924 int s; 925 926 s = splvm(); 927 if (m->queue != PQ_ACTIVE) { 928 if ((m->queue - m->pc) == PQ_CACHE) 929 mycpu->gd_cnt.v_reactivated++; 930 931 vm_page_unqueue(m); 932 933 if (m->wire_count == 0 && (m->flags & PG_UNMANAGED) == 0) { 934 m->queue = PQ_ACTIVE; 935 vm_page_queues[PQ_ACTIVE].lcnt++; 936 TAILQ_INSERT_TAIL(&vm_page_queues[PQ_ACTIVE].pl, m, pageq); 937 if (m->act_count < ACT_INIT) 938 m->act_count = ACT_INIT; 939 vmstats.v_active_count++; 940 } 941 } else { 942 if (m->act_count < ACT_INIT) 943 m->act_count = ACT_INIT; 944 } 945 946 splx(s); 947 } 948 949 /* 950 * vm_page_free_wakeup: 951 * 952 * Helper routine for vm_page_free_toq() and vm_page_cache(). This 953 * routine is called when a page has been added to the cache or free 954 * queues. 955 * 956 * This routine may not block. 957 * This routine must be called at splvm() 958 */ 959 static __inline void 960 vm_page_free_wakeup(void) 961 { 962 /* 963 * if pageout daemon needs pages, then tell it that there are 964 * some free. 965 */ 966 if (vm_pageout_pages_needed && 967 vmstats.v_cache_count + vmstats.v_free_count >= vmstats.v_pageout_free_min) { 968 wakeup(&vm_pageout_pages_needed); 969 vm_pageout_pages_needed = 0; 970 } 971 /* 972 * wakeup processes that are waiting on memory if we hit a 973 * high water mark. And wakeup scheduler process if we have 974 * lots of memory. this process will swapin processes. 975 */ 976 if (vm_pages_needed && !vm_page_count_min()) { 977 vm_pages_needed = 0; 978 wakeup(&vmstats.v_free_count); 979 } 980 } 981 982 /* 983 * vm_page_free_toq: 984 * 985 * Returns the given page to the PQ_FREE list, 986 * disassociating it with any VM object. 987 * 988 * Object and page must be locked prior to entry. 989 * This routine may not block. 990 */ 991 992 void 993 vm_page_free_toq(vm_page_t m) 994 { 995 int s; 996 struct vpgqueues *pq; 997 vm_object_t object = m->object; 998 999 s = splvm(); 1000 1001 mycpu->gd_cnt.v_tfree++; 1002 1003 if (m->busy || ((m->queue - m->pc) == PQ_FREE)) { 1004 printf( 1005 "vm_page_free: pindex(%lu), busy(%d), PG_BUSY(%d), hold(%d)\n", 1006 (u_long)m->pindex, m->busy, (m->flags & PG_BUSY) ? 1 : 0, 1007 m->hold_count); 1008 if ((m->queue - m->pc) == PQ_FREE) 1009 panic("vm_page_free: freeing free page"); 1010 else 1011 panic("vm_page_free: freeing busy page"); 1012 } 1013 1014 /* 1015 * unqueue, then remove page. Note that we cannot destroy 1016 * the page here because we do not want to call the pager's 1017 * callback routine until after we've put the page on the 1018 * appropriate free queue. 1019 */ 1020 1021 vm_page_unqueue_nowakeup(m); 1022 vm_page_remove(m); 1023 1024 /* 1025 * If fictitious remove object association and 1026 * return, otherwise delay object association removal. 1027 */ 1028 1029 if ((m->flags & PG_FICTITIOUS) != 0) { 1030 splx(s); 1031 return; 1032 } 1033 1034 m->valid = 0; 1035 vm_page_undirty(m); 1036 1037 if (m->wire_count != 0) { 1038 if (m->wire_count > 1) { 1039 panic("vm_page_free: invalid wire count (%d), pindex: 0x%lx", 1040 m->wire_count, (long)m->pindex); 1041 } 1042 panic("vm_page_free: freeing wired page\n"); 1043 } 1044 1045 /* 1046 * If we've exhausted the object's resident pages we want to free 1047 * it up. 1048 */ 1049 1050 if (object && 1051 (object->type == OBJT_VNODE) && 1052 ((object->flags & OBJ_DEAD) == 0) 1053 ) { 1054 struct vnode *vp = (struct vnode *)object->handle; 1055 1056 if (vp && VSHOULDFREE(vp)) 1057 vfree(vp); 1058 } 1059 1060 /* 1061 * Clear the UNMANAGED flag when freeing an unmanaged page. 1062 */ 1063 1064 if (m->flags & PG_UNMANAGED) { 1065 m->flags &= ~PG_UNMANAGED; 1066 } else { 1067 #ifdef __alpha__ 1068 pmap_page_is_free(m); 1069 #endif 1070 } 1071 1072 if (m->hold_count != 0) { 1073 m->flags &= ~PG_ZERO; 1074 m->queue = PQ_HOLD; 1075 } else 1076 m->queue = PQ_FREE + m->pc; 1077 pq = &vm_page_queues[m->queue]; 1078 pq->lcnt++; 1079 ++(*pq->cnt); 1080 1081 /* 1082 * Put zero'd pages on the end ( where we look for zero'd pages 1083 * first ) and non-zerod pages at the head. 1084 */ 1085 1086 if (m->flags & PG_ZERO) { 1087 TAILQ_INSERT_TAIL(&pq->pl, m, pageq); 1088 ++vm_page_zero_count; 1089 } else { 1090 TAILQ_INSERT_HEAD(&pq->pl, m, pageq); 1091 } 1092 1093 vm_page_free_wakeup(); 1094 1095 splx(s); 1096 } 1097 1098 /* 1099 * vm_page_unmanage: 1100 * 1101 * Prevent PV management from being done on the page. The page is 1102 * removed from the paging queues as if it were wired, and as a 1103 * consequence of no longer being managed the pageout daemon will not 1104 * touch it (since there is no way to locate the pte mappings for the 1105 * page). madvise() calls that mess with the pmap will also no longer 1106 * operate on the page. 1107 * 1108 * Beyond that the page is still reasonably 'normal'. Freeing the page 1109 * will clear the flag. 1110 * 1111 * This routine is used by OBJT_PHYS objects - objects using unswappable 1112 * physical memory as backing store rather then swap-backed memory and 1113 * will eventually be extended to support 4MB unmanaged physical 1114 * mappings. 1115 */ 1116 1117 void 1118 vm_page_unmanage(vm_page_t m) 1119 { 1120 int s; 1121 1122 s = splvm(); 1123 if ((m->flags & PG_UNMANAGED) == 0) { 1124 if (m->wire_count == 0) 1125 vm_page_unqueue(m); 1126 } 1127 vm_page_flag_set(m, PG_UNMANAGED); 1128 splx(s); 1129 } 1130 1131 /* 1132 * vm_page_wire: 1133 * 1134 * Mark this page as wired down by yet 1135 * another map, removing it from paging queues 1136 * as necessary. 1137 * 1138 * The page queues must be locked. 1139 * This routine may not block. 1140 */ 1141 void 1142 vm_page_wire(vm_page_t m) 1143 { 1144 int s; 1145 1146 /* 1147 * Only bump the wire statistics if the page is not already wired, 1148 * and only unqueue the page if it is on some queue (if it is unmanaged 1149 * it is already off the queues). 1150 */ 1151 s = splvm(); 1152 if (m->wire_count == 0) { 1153 if ((m->flags & PG_UNMANAGED) == 0) 1154 vm_page_unqueue(m); 1155 vmstats.v_wire_count++; 1156 } 1157 m->wire_count++; 1158 KASSERT(m->wire_count != 0, 1159 ("vm_page_wire: wire_count overflow m=%p", m)); 1160 1161 splx(s); 1162 vm_page_flag_set(m, PG_MAPPED); 1163 } 1164 1165 /* 1166 * vm_page_unwire: 1167 * 1168 * Release one wiring of this page, potentially 1169 * enabling it to be paged again. 1170 * 1171 * Many pages placed on the inactive queue should actually go 1172 * into the cache, but it is difficult to figure out which. What 1173 * we do instead, if the inactive target is well met, is to put 1174 * clean pages at the head of the inactive queue instead of the tail. 1175 * This will cause them to be moved to the cache more quickly and 1176 * if not actively re-referenced, freed more quickly. If we just 1177 * stick these pages at the end of the inactive queue, heavy filesystem 1178 * meta-data accesses can cause an unnecessary paging load on memory bound 1179 * processes. This optimization causes one-time-use metadata to be 1180 * reused more quickly. 1181 * 1182 * BUT, if we are in a low-memory situation we have no choice but to 1183 * put clean pages on the cache queue. 1184 * 1185 * A number of routines use vm_page_unwire() to guarantee that the page 1186 * will go into either the inactive or active queues, and will NEVER 1187 * be placed in the cache - for example, just after dirtying a page. 1188 * dirty pages in the cache are not allowed. 1189 * 1190 * The page queues must be locked. 1191 * This routine may not block. 1192 */ 1193 void 1194 vm_page_unwire(vm_page_t m, int activate) 1195 { 1196 int s; 1197 1198 s = splvm(); 1199 1200 if (m->wire_count > 0) { 1201 m->wire_count--; 1202 if (m->wire_count == 0) { 1203 vmstats.v_wire_count--; 1204 if (m->flags & PG_UNMANAGED) { 1205 ; 1206 } else if (activate) { 1207 TAILQ_INSERT_TAIL(&vm_page_queues[PQ_ACTIVE].pl, m, pageq); 1208 m->queue = PQ_ACTIVE; 1209 vm_page_queues[PQ_ACTIVE].lcnt++; 1210 vmstats.v_active_count++; 1211 } else { 1212 vm_page_flag_clear(m, PG_WINATCFLS); 1213 TAILQ_INSERT_TAIL(&vm_page_queues[PQ_INACTIVE].pl, m, pageq); 1214 m->queue = PQ_INACTIVE; 1215 vm_page_queues[PQ_INACTIVE].lcnt++; 1216 vmstats.v_inactive_count++; 1217 } 1218 } 1219 } else { 1220 panic("vm_page_unwire: invalid wire count: %d\n", m->wire_count); 1221 } 1222 splx(s); 1223 } 1224 1225 1226 /* 1227 * Move the specified page to the inactive queue. If the page has 1228 * any associated swap, the swap is deallocated. 1229 * 1230 * Normally athead is 0 resulting in LRU operation. athead is set 1231 * to 1 if we want this page to be 'as if it were placed in the cache', 1232 * except without unmapping it from the process address space. 1233 * 1234 * This routine may not block. 1235 */ 1236 static __inline void 1237 _vm_page_deactivate(vm_page_t m, int athead) 1238 { 1239 int s; 1240 1241 /* 1242 * Ignore if already inactive. 1243 */ 1244 if (m->queue == PQ_INACTIVE) 1245 return; 1246 1247 s = splvm(); 1248 if (m->wire_count == 0 && (m->flags & PG_UNMANAGED) == 0) { 1249 if ((m->queue - m->pc) == PQ_CACHE) 1250 mycpu->gd_cnt.v_reactivated++; 1251 vm_page_flag_clear(m, PG_WINATCFLS); 1252 vm_page_unqueue(m); 1253 if (athead) 1254 TAILQ_INSERT_HEAD(&vm_page_queues[PQ_INACTIVE].pl, m, pageq); 1255 else 1256 TAILQ_INSERT_TAIL(&vm_page_queues[PQ_INACTIVE].pl, m, pageq); 1257 m->queue = PQ_INACTIVE; 1258 vm_page_queues[PQ_INACTIVE].lcnt++; 1259 vmstats.v_inactive_count++; 1260 } 1261 splx(s); 1262 } 1263 1264 void 1265 vm_page_deactivate(vm_page_t m) 1266 { 1267 _vm_page_deactivate(m, 0); 1268 } 1269 1270 /* 1271 * vm_page_try_to_cache: 1272 * 1273 * Returns 0 on failure, 1 on success 1274 */ 1275 int 1276 vm_page_try_to_cache(vm_page_t m) 1277 { 1278 if (m->dirty || m->hold_count || m->busy || m->wire_count || 1279 (m->flags & (PG_BUSY|PG_UNMANAGED))) { 1280 return(0); 1281 } 1282 vm_page_test_dirty(m); 1283 if (m->dirty) 1284 return(0); 1285 vm_page_cache(m); 1286 return(1); 1287 } 1288 1289 /* 1290 * vm_page_try_to_free() 1291 * 1292 * Attempt to free the page. If we cannot free it, we do nothing. 1293 * 1 is returned on success, 0 on failure. 1294 */ 1295 1296 int 1297 vm_page_try_to_free(vm_page_t m) 1298 { 1299 if (m->dirty || m->hold_count || m->busy || m->wire_count || 1300 (m->flags & (PG_BUSY|PG_UNMANAGED))) { 1301 return(0); 1302 } 1303 vm_page_test_dirty(m); 1304 if (m->dirty) 1305 return(0); 1306 vm_page_busy(m); 1307 vm_page_protect(m, VM_PROT_NONE); 1308 vm_page_free(m); 1309 return(1); 1310 } 1311 1312 1313 /* 1314 * vm_page_cache 1315 * 1316 * Put the specified page onto the page cache queue (if appropriate). 1317 * 1318 * This routine may not block. 1319 */ 1320 void 1321 vm_page_cache(vm_page_t m) 1322 { 1323 int s; 1324 1325 if ((m->flags & (PG_BUSY|PG_UNMANAGED)) || m->busy || m->wire_count) { 1326 printf("vm_page_cache: attempting to cache busy page\n"); 1327 return; 1328 } 1329 if ((m->queue - m->pc) == PQ_CACHE) 1330 return; 1331 1332 /* 1333 * Remove all pmaps and indicate that the page is not 1334 * writeable or mapped. 1335 */ 1336 1337 vm_page_protect(m, VM_PROT_NONE); 1338 if (m->dirty != 0) { 1339 panic("vm_page_cache: caching a dirty page, pindex: %ld", 1340 (long)m->pindex); 1341 } 1342 s = splvm(); 1343 vm_page_unqueue_nowakeup(m); 1344 m->queue = PQ_CACHE + m->pc; 1345 vm_page_queues[m->queue].lcnt++; 1346 TAILQ_INSERT_TAIL(&vm_page_queues[m->queue].pl, m, pageq); 1347 vmstats.v_cache_count++; 1348 vm_page_free_wakeup(); 1349 splx(s); 1350 } 1351 1352 /* 1353 * vm_page_dontneed 1354 * 1355 * Cache, deactivate, or do nothing as appropriate. This routine 1356 * is typically used by madvise() MADV_DONTNEED. 1357 * 1358 * Generally speaking we want to move the page into the cache so 1359 * it gets reused quickly. However, this can result in a silly syndrome 1360 * due to the page recycling too quickly. Small objects will not be 1361 * fully cached. On the otherhand, if we move the page to the inactive 1362 * queue we wind up with a problem whereby very large objects 1363 * unnecessarily blow away our inactive and cache queues. 1364 * 1365 * The solution is to move the pages based on a fixed weighting. We 1366 * either leave them alone, deactivate them, or move them to the cache, 1367 * where moving them to the cache has the highest weighting. 1368 * By forcing some pages into other queues we eventually force the 1369 * system to balance the queues, potentially recovering other unrelated 1370 * space from active. The idea is to not force this to happen too 1371 * often. 1372 */ 1373 1374 void 1375 vm_page_dontneed(vm_page_t m) 1376 { 1377 static int dnweight; 1378 int dnw; 1379 int head; 1380 1381 dnw = ++dnweight; 1382 1383 /* 1384 * occassionally leave the page alone 1385 */ 1386 1387 if ((dnw & 0x01F0) == 0 || 1388 m->queue == PQ_INACTIVE || 1389 m->queue - m->pc == PQ_CACHE 1390 ) { 1391 if (m->act_count >= ACT_INIT) 1392 --m->act_count; 1393 return; 1394 } 1395 1396 if (m->dirty == 0) 1397 vm_page_test_dirty(m); 1398 1399 if (m->dirty || (dnw & 0x0070) == 0) { 1400 /* 1401 * Deactivate the page 3 times out of 32. 1402 */ 1403 head = 0; 1404 } else { 1405 /* 1406 * Cache the page 28 times out of every 32. Note that 1407 * the page is deactivated instead of cached, but placed 1408 * at the head of the queue instead of the tail. 1409 */ 1410 head = 1; 1411 } 1412 _vm_page_deactivate(m, head); 1413 } 1414 1415 /* 1416 * Grab a page, waiting until we are waken up due to the page 1417 * changing state. We keep on waiting, if the page continues 1418 * to be in the object. If the page doesn't exist, allocate it. 1419 * 1420 * This routine may block. 1421 */ 1422 vm_page_t 1423 vm_page_grab(vm_object_t object, vm_pindex_t pindex, int allocflags) 1424 { 1425 1426 vm_page_t m; 1427 int s, generation; 1428 1429 retrylookup: 1430 if ((m = vm_page_lookup(object, pindex)) != NULL) { 1431 if (m->busy || (m->flags & PG_BUSY)) { 1432 generation = object->generation; 1433 1434 s = splvm(); 1435 while ((object->generation == generation) && 1436 (m->busy || (m->flags & PG_BUSY))) { 1437 vm_page_flag_set(m, PG_WANTED | PG_REFERENCED); 1438 tsleep(m, 0, "pgrbwt", 0); 1439 if ((allocflags & VM_ALLOC_RETRY) == 0) { 1440 splx(s); 1441 return NULL; 1442 } 1443 } 1444 splx(s); 1445 goto retrylookup; 1446 } else { 1447 vm_page_busy(m); 1448 return m; 1449 } 1450 } 1451 1452 m = vm_page_alloc(object, pindex, allocflags & ~VM_ALLOC_RETRY); 1453 if (m == NULL) { 1454 VM_WAIT; 1455 if ((allocflags & VM_ALLOC_RETRY) == 0) 1456 return NULL; 1457 goto retrylookup; 1458 } 1459 1460 return m; 1461 } 1462 1463 /* 1464 * Mapping function for valid bits or for dirty bits in 1465 * a page. May not block. 1466 * 1467 * Inputs are required to range within a page. 1468 */ 1469 1470 __inline int 1471 vm_page_bits(int base, int size) 1472 { 1473 int first_bit; 1474 int last_bit; 1475 1476 KASSERT( 1477 base + size <= PAGE_SIZE, 1478 ("vm_page_bits: illegal base/size %d/%d", base, size) 1479 ); 1480 1481 if (size == 0) /* handle degenerate case */ 1482 return(0); 1483 1484 first_bit = base >> DEV_BSHIFT; 1485 last_bit = (base + size - 1) >> DEV_BSHIFT; 1486 1487 return ((2 << last_bit) - (1 << first_bit)); 1488 } 1489 1490 /* 1491 * vm_page_set_validclean: 1492 * 1493 * Sets portions of a page valid and clean. The arguments are expected 1494 * to be DEV_BSIZE aligned but if they aren't the bitmap is inclusive 1495 * of any partial chunks touched by the range. The invalid portion of 1496 * such chunks will be zero'd. 1497 * 1498 * This routine may not block. 1499 * 1500 * (base + size) must be less then or equal to PAGE_SIZE. 1501 */ 1502 void 1503 vm_page_set_validclean(vm_page_t m, int base, int size) 1504 { 1505 int pagebits; 1506 int frag; 1507 int endoff; 1508 1509 if (size == 0) /* handle degenerate case */ 1510 return; 1511 1512 /* 1513 * If the base is not DEV_BSIZE aligned and the valid 1514 * bit is clear, we have to zero out a portion of the 1515 * first block. 1516 */ 1517 1518 if ((frag = base & ~(DEV_BSIZE - 1)) != base && 1519 (m->valid & (1 << (base >> DEV_BSHIFT))) == 0 1520 ) { 1521 pmap_zero_page_area( 1522 VM_PAGE_TO_PHYS(m), 1523 frag, 1524 base - frag 1525 ); 1526 } 1527 1528 /* 1529 * If the ending offset is not DEV_BSIZE aligned and the 1530 * valid bit is clear, we have to zero out a portion of 1531 * the last block. 1532 */ 1533 1534 endoff = base + size; 1535 1536 if ((frag = endoff & ~(DEV_BSIZE - 1)) != endoff && 1537 (m->valid & (1 << (endoff >> DEV_BSHIFT))) == 0 1538 ) { 1539 pmap_zero_page_area( 1540 VM_PAGE_TO_PHYS(m), 1541 endoff, 1542 DEV_BSIZE - (endoff & (DEV_BSIZE - 1)) 1543 ); 1544 } 1545 1546 /* 1547 * Set valid, clear dirty bits. If validating the entire 1548 * page we can safely clear the pmap modify bit. We also 1549 * use this opportunity to clear the PG_NOSYNC flag. If a process 1550 * takes a write fault on a MAP_NOSYNC memory area the flag will 1551 * be set again. 1552 * 1553 * We set valid bits inclusive of any overlap, but we can only 1554 * clear dirty bits for DEV_BSIZE chunks that are fully within 1555 * the range. 1556 */ 1557 1558 pagebits = vm_page_bits(base, size); 1559 m->valid |= pagebits; 1560 #if 0 /* NOT YET */ 1561 if ((frag = base & (DEV_BSIZE - 1)) != 0) { 1562 frag = DEV_BSIZE - frag; 1563 base += frag; 1564 size -= frag; 1565 if (size < 0) 1566 size = 0; 1567 } 1568 pagebits = vm_page_bits(base, size & (DEV_BSIZE - 1)); 1569 #endif 1570 m->dirty &= ~pagebits; 1571 if (base == 0 && size == PAGE_SIZE) { 1572 pmap_clear_modify(m); 1573 vm_page_flag_clear(m, PG_NOSYNC); 1574 } 1575 } 1576 1577 #if 0 1578 1579 void 1580 vm_page_set_dirty(vm_page_t m, int base, int size) 1581 { 1582 m->dirty |= vm_page_bits(base, size); 1583 } 1584 1585 #endif 1586 1587 void 1588 vm_page_clear_dirty(vm_page_t m, int base, int size) 1589 { 1590 m->dirty &= ~vm_page_bits(base, size); 1591 } 1592 1593 /* 1594 * vm_page_set_invalid: 1595 * 1596 * Invalidates DEV_BSIZE'd chunks within a page. Both the 1597 * valid and dirty bits for the effected areas are cleared. 1598 * 1599 * May not block. 1600 */ 1601 void 1602 vm_page_set_invalid(vm_page_t m, int base, int size) 1603 { 1604 int bits; 1605 1606 bits = vm_page_bits(base, size); 1607 m->valid &= ~bits; 1608 m->dirty &= ~bits; 1609 m->object->generation++; 1610 } 1611 1612 /* 1613 * vm_page_zero_invalid() 1614 * 1615 * The kernel assumes that the invalid portions of a page contain 1616 * garbage, but such pages can be mapped into memory by user code. 1617 * When this occurs, we must zero out the non-valid portions of the 1618 * page so user code sees what it expects. 1619 * 1620 * Pages are most often semi-valid when the end of a file is mapped 1621 * into memory and the file's size is not page aligned. 1622 */ 1623 1624 void 1625 vm_page_zero_invalid(vm_page_t m, boolean_t setvalid) 1626 { 1627 int b; 1628 int i; 1629 1630 /* 1631 * Scan the valid bits looking for invalid sections that 1632 * must be zerod. Invalid sub-DEV_BSIZE'd areas ( where the 1633 * valid bit may be set ) have already been zerod by 1634 * vm_page_set_validclean(). 1635 */ 1636 1637 for (b = i = 0; i <= PAGE_SIZE / DEV_BSIZE; ++i) { 1638 if (i == (PAGE_SIZE / DEV_BSIZE) || 1639 (m->valid & (1 << i)) 1640 ) { 1641 if (i > b) { 1642 pmap_zero_page_area( 1643 VM_PAGE_TO_PHYS(m), 1644 b << DEV_BSHIFT, 1645 (i - b) << DEV_BSHIFT 1646 ); 1647 } 1648 b = i + 1; 1649 } 1650 } 1651 1652 /* 1653 * setvalid is TRUE when we can safely set the zero'd areas 1654 * as being valid. We can do this if there are no cache consistency 1655 * issues. e.g. it is ok to do with UFS, but not ok to do with NFS. 1656 */ 1657 1658 if (setvalid) 1659 m->valid = VM_PAGE_BITS_ALL; 1660 } 1661 1662 /* 1663 * vm_page_is_valid: 1664 * 1665 * Is (partial) page valid? Note that the case where size == 0 1666 * will return FALSE in the degenerate case where the page is 1667 * entirely invalid, and TRUE otherwise. 1668 * 1669 * May not block. 1670 */ 1671 1672 int 1673 vm_page_is_valid(vm_page_t m, int base, int size) 1674 { 1675 int bits = vm_page_bits(base, size); 1676 1677 if (m->valid && ((m->valid & bits) == bits)) 1678 return 1; 1679 else 1680 return 0; 1681 } 1682 1683 /* 1684 * update dirty bits from pmap/mmu. May not block. 1685 */ 1686 1687 void 1688 vm_page_test_dirty(vm_page_t m) 1689 { 1690 if ((m->dirty != VM_PAGE_BITS_ALL) && pmap_is_modified(m)) { 1691 vm_page_dirty(m); 1692 } 1693 } 1694 1695 /* 1696 * This interface is for merging with malloc() someday. 1697 * Even if we never implement compaction so that contiguous allocation 1698 * works after initialization time, malloc()'s data structures are good 1699 * for statistics and for allocations of less than a page. 1700 */ 1701 void * 1702 contigmalloc1( 1703 unsigned long size, /* should be size_t here and for malloc() */ 1704 struct malloc_type *type, 1705 int flags, 1706 unsigned long low, 1707 unsigned long high, 1708 unsigned long alignment, 1709 unsigned long boundary, 1710 vm_map_t map) 1711 { 1712 int i, s, start; 1713 vm_offset_t addr, phys, tmp_addr; 1714 int pass; 1715 vm_page_t pga = vm_page_array; 1716 1717 size = round_page(size); 1718 if (size == 0) 1719 panic("contigmalloc1: size must not be 0"); 1720 if ((alignment & (alignment - 1)) != 0) 1721 panic("contigmalloc1: alignment must be a power of 2"); 1722 if ((boundary & (boundary - 1)) != 0) 1723 panic("contigmalloc1: boundary must be a power of 2"); 1724 1725 start = 0; 1726 for (pass = 0; pass <= 1; pass++) { 1727 s = splvm(); 1728 again: 1729 /* 1730 * Find first page in array that is free, within range, aligned, and 1731 * such that the boundary won't be crossed. 1732 */ 1733 for (i = start; i < vmstats.v_page_count; i++) { 1734 int pqtype; 1735 phys = VM_PAGE_TO_PHYS(&pga[i]); 1736 pqtype = pga[i].queue - pga[i].pc; 1737 if (((pqtype == PQ_FREE) || (pqtype == PQ_CACHE)) && 1738 (phys >= low) && (phys < high) && 1739 ((phys & (alignment - 1)) == 0) && 1740 (((phys ^ (phys + size - 1)) & ~(boundary - 1)) == 0)) 1741 break; 1742 } 1743 1744 /* 1745 * If the above failed or we will exceed the upper bound, fail. 1746 */ 1747 if ((i == vmstats.v_page_count) || 1748 ((VM_PAGE_TO_PHYS(&pga[i]) + size) > high)) { 1749 vm_page_t m, next; 1750 1751 again1: 1752 for (m = TAILQ_FIRST(&vm_page_queues[PQ_INACTIVE].pl); 1753 m != NULL; 1754 m = next) { 1755 1756 KASSERT(m->queue == PQ_INACTIVE, 1757 ("contigmalloc1: page %p is not PQ_INACTIVE", m)); 1758 1759 next = TAILQ_NEXT(m, pageq); 1760 if (vm_page_sleep_busy(m, TRUE, "vpctw0")) 1761 goto again1; 1762 vm_page_test_dirty(m); 1763 if (m->dirty) { 1764 if (m->object->type == OBJT_VNODE) { 1765 vn_lock(m->object->handle, LK_EXCLUSIVE | LK_RETRY, curthread); 1766 vm_object_page_clean(m->object, 0, 0, OBJPC_SYNC); 1767 VOP_UNLOCK(m->object->handle, 0, curthread); 1768 goto again1; 1769 } else if (m->object->type == OBJT_SWAP || 1770 m->object->type == OBJT_DEFAULT) { 1771 vm_pageout_flush(&m, 1, 0); 1772 goto again1; 1773 } 1774 } 1775 if ((m->dirty == 0) && (m->busy == 0) && (m->hold_count == 0)) 1776 vm_page_cache(m); 1777 } 1778 1779 for (m = TAILQ_FIRST(&vm_page_queues[PQ_ACTIVE].pl); 1780 m != NULL; 1781 m = next) { 1782 1783 KASSERT(m->queue == PQ_ACTIVE, 1784 ("contigmalloc1: page %p is not PQ_ACTIVE", m)); 1785 1786 next = TAILQ_NEXT(m, pageq); 1787 if (vm_page_sleep_busy(m, TRUE, "vpctw1")) 1788 goto again1; 1789 vm_page_test_dirty(m); 1790 if (m->dirty) { 1791 if (m->object->type == OBJT_VNODE) { 1792 vn_lock(m->object->handle, LK_EXCLUSIVE | LK_RETRY, curthread); 1793 vm_object_page_clean(m->object, 0, 0, OBJPC_SYNC); 1794 VOP_UNLOCK(m->object->handle, 0, curthread); 1795 goto again1; 1796 } else if (m->object->type == OBJT_SWAP || 1797 m->object->type == OBJT_DEFAULT) { 1798 vm_pageout_flush(&m, 1, 0); 1799 goto again1; 1800 } 1801 } 1802 if ((m->dirty == 0) && (m->busy == 0) && (m->hold_count == 0)) 1803 vm_page_cache(m); 1804 } 1805 1806 splx(s); 1807 continue; 1808 } 1809 start = i; 1810 1811 /* 1812 * Check successive pages for contiguous and free. 1813 */ 1814 for (i = start + 1; i < (start + size / PAGE_SIZE); i++) { 1815 int pqtype; 1816 pqtype = pga[i].queue - pga[i].pc; 1817 if ((VM_PAGE_TO_PHYS(&pga[i]) != 1818 (VM_PAGE_TO_PHYS(&pga[i - 1]) + PAGE_SIZE)) || 1819 ((pqtype != PQ_FREE) && (pqtype != PQ_CACHE))) { 1820 start++; 1821 goto again; 1822 } 1823 } 1824 1825 for (i = start; i < (start + size / PAGE_SIZE); i++) { 1826 int pqtype; 1827 vm_page_t m = &pga[i]; 1828 1829 pqtype = m->queue - m->pc; 1830 if (pqtype == PQ_CACHE) { 1831 vm_page_busy(m); 1832 vm_page_free(m); 1833 } 1834 vm_page_unqueue_nowakeup(m); 1835 m->valid = VM_PAGE_BITS_ALL; 1836 if (m->flags & PG_ZERO) 1837 vm_page_zero_count--; 1838 m->flags = 0; 1839 KASSERT(m->dirty == 0, ("contigmalloc1: page %p was dirty", m)); 1840 m->wire_count = 0; 1841 m->busy = 0; 1842 m->object = NULL; 1843 } 1844 1845 /* 1846 * We've found a contiguous chunk that meets are requirements. 1847 * Allocate kernel VM, unfree and assign the physical pages to it and 1848 * return kernel VM pointer. 1849 */ 1850 vm_map_lock(map); 1851 if (vm_map_findspace(map, vm_map_min(map), size, &addr) != 1852 KERN_SUCCESS) { 1853 /* 1854 * XXX We almost never run out of kernel virtual 1855 * space, so we don't make the allocated memory 1856 * above available. 1857 */ 1858 vm_map_unlock(map); 1859 splx(s); 1860 return (NULL); 1861 } 1862 vm_object_reference(kernel_object); 1863 vm_map_insert(map, kernel_object, addr - VM_MIN_KERNEL_ADDRESS, 1864 addr, addr + size, VM_PROT_ALL, VM_PROT_ALL, 0); 1865 vm_map_unlock(map); 1866 1867 tmp_addr = addr; 1868 for (i = start; i < (start + size / PAGE_SIZE); i++) { 1869 vm_page_t m = &pga[i]; 1870 vm_page_insert(m, kernel_object, 1871 OFF_TO_IDX(tmp_addr - VM_MIN_KERNEL_ADDRESS)); 1872 tmp_addr += PAGE_SIZE; 1873 } 1874 vm_map_pageable(map, addr, addr + size, FALSE); 1875 1876 splx(s); 1877 return ((void *)addr); 1878 } 1879 return NULL; 1880 } 1881 1882 void * 1883 contigmalloc( 1884 unsigned long size, /* should be size_t here and for malloc() */ 1885 struct malloc_type *type, 1886 int flags, 1887 unsigned long low, 1888 unsigned long high, 1889 unsigned long alignment, 1890 unsigned long boundary) 1891 { 1892 return contigmalloc1(size, type, flags, low, high, alignment, boundary, 1893 kernel_map); 1894 } 1895 1896 void 1897 contigfree(void *addr, unsigned long size, struct malloc_type *type) 1898 { 1899 kmem_free(kernel_map, (vm_offset_t)addr, size); 1900 } 1901 1902 vm_offset_t 1903 vm_page_alloc_contig( 1904 vm_offset_t size, 1905 vm_offset_t low, 1906 vm_offset_t high, 1907 vm_offset_t alignment) 1908 { 1909 return ((vm_offset_t)contigmalloc1(size, M_DEVBUF, M_NOWAIT, low, high, 1910 alignment, 0ul, kernel_map)); 1911 } 1912 1913 #include "opt_ddb.h" 1914 #ifdef DDB 1915 #include <sys/kernel.h> 1916 1917 #include <ddb/ddb.h> 1918 1919 DB_SHOW_COMMAND(page, vm_page_print_page_info) 1920 { 1921 db_printf("vmstats.v_free_count: %d\n", vmstats.v_free_count); 1922 db_printf("vmstats.v_cache_count: %d\n", vmstats.v_cache_count); 1923 db_printf("vmstats.v_inactive_count: %d\n", vmstats.v_inactive_count); 1924 db_printf("vmstats.v_active_count: %d\n", vmstats.v_active_count); 1925 db_printf("vmstats.v_wire_count: %d\n", vmstats.v_wire_count); 1926 db_printf("vmstats.v_free_reserved: %d\n", vmstats.v_free_reserved); 1927 db_printf("vmstats.v_free_min: %d\n", vmstats.v_free_min); 1928 db_printf("vmstats.v_free_target: %d\n", vmstats.v_free_target); 1929 db_printf("vmstats.v_cache_min: %d\n", vmstats.v_cache_min); 1930 db_printf("vmstats.v_inactive_target: %d\n", vmstats.v_inactive_target); 1931 } 1932 1933 DB_SHOW_COMMAND(pageq, vm_page_print_pageq_info) 1934 { 1935 int i; 1936 db_printf("PQ_FREE:"); 1937 for(i=0;i<PQ_L2_SIZE;i++) { 1938 db_printf(" %d", vm_page_queues[PQ_FREE + i].lcnt); 1939 } 1940 db_printf("\n"); 1941 1942 db_printf("PQ_CACHE:"); 1943 for(i=0;i<PQ_L2_SIZE;i++) { 1944 db_printf(" %d", vm_page_queues[PQ_CACHE + i].lcnt); 1945 } 1946 db_printf("\n"); 1947 1948 db_printf("PQ_ACTIVE: %d, PQ_INACTIVE: %d\n", 1949 vm_page_queues[PQ_ACTIVE].lcnt, 1950 vm_page_queues[PQ_INACTIVE].lcnt); 1951 } 1952 #endif /* DDB */ 1953