vm_pageout.c revision 1810
1/* 2 * Copyright (c) 1991 Regents of the University of California. 3 * All rights reserved. 4 * Copyright (c) 1994 John S. Dyson 5 * All rights reserved. 6 * Copyright (c) 1994 David Greenman 7 * All rights reserved. 8 * 9 * This code is derived from software contributed to Berkeley by 10 * The Mach Operating System project at Carnegie-Mellon University. 11 * 12 * Redistribution and use in source and binary forms, with or without 13 * modification, are permitted provided that the following conditions 14 * are met: 15 * 1. Redistributions of source code must retain the above copyright 16 * notice, this list of conditions and the following disclaimer. 17 * 2. Redistributions in binary form must reproduce the above copyright 18 * notice, this list of conditions and the following disclaimer in the 19 * documentation and/or other materials provided with the distribution. 20 * 3. All advertising materials mentioning features or use of this software 21 * must display the following acknowledgement: 22 * This product includes software developed by the University of 23 * California, Berkeley and its contributors. 24 * 4. Neither the name of the University nor the names of its contributors 25 * may be used to endorse or promote products derived from this software 26 * without specific prior written permission. 27 * 28 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 29 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 30 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 31 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 32 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 33 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 34 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 35 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 36 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 37 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 38 * SUCH DAMAGE. 39 * 40 * @(#)vm_pageout.c 7.4 (Berkeley) 5/7/91 41 * 42 * 43 * Copyright (c) 1987, 1990 Carnegie-Mellon University. 44 * All rights reserved. 45 * 46 * Authors: Avadis Tevanian, Jr., Michael Wayne Young 47 * 48 * Permission to use, copy, modify and distribute this software and 49 * its documentation is hereby granted, provided that both the copyright 50 * notice and this permission notice appear in all copies of the 51 * software, derivative works or modified versions, and any portions 52 * thereof, and that both notices appear in supporting documentation. 53 * 54 * CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS" 55 * CONDITION. CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND 56 * FOR ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE. 57 * 58 * Carnegie Mellon requests users of this software to return to 59 * 60 * Software Distribution Coordinator or Software.Distribution@CS.CMU.EDU 61 * School of Computer Science 62 * Carnegie Mellon University 63 * Pittsburgh PA 15213-3890 64 * 65 * any improvements or extensions that they make and grant Carnegie the 66 * rights to redistribute these changes. 67 * 68 * $Id: vm_pageout.c,v 1.3 1994/06/06 11:56:27 davidg Exp $ 69 */ 70 71/* 72 * The proverbial page-out daemon. 73 */ 74 75#include <sys/param.h> 76#include <sys/systm.h> 77#include <sys/proc.h> 78#include <sys/resourcevar.h> 79#include <sys/malloc.h> 80 81#include <vm/vm.h> 82#include <vm/vm_page.h> 83#include <vm/vm_pageout.h> 84 85extern vm_map_t kmem_map; 86int vm_pages_needed; /* Event on which pageout daemon sleeps */ 87int vm_pagescanner; /* Event on which pagescanner sleeps */ 88int vm_pageout_free_min = 0; /* Stop pageout to wait for pagers at this free level */ 89 90int vm_pageout_pages_needed = 0; /* flag saying that the pageout daemon needs pages */ 91int vm_page_pagesfreed; 92 93extern int npendingio; 94extern int hz; 95int vm_pageout_proc_limit; 96extern int nswiodone; 97extern int swap_pager_full; 98extern int swap_pager_ready(); 99 100#define MAXREF 32767 101 102#define MAXSCAN 512 /* maximum number of pages to scan in active queue */ 103 /* set the "clock" hands to be (MAXSCAN * 4096) Bytes */ 104#define ACT_DECLINE 1 105#define ACT_ADVANCE 3 106#define ACT_MAX 300 107 108#define LOWATER ((2048*1024)/NBPG) 109 110#define VM_PAGEOUT_PAGE_COUNT 8 111static vm_offset_t vm_space_needed; 112int vm_pageout_req_do_stats; 113 114int vm_page_max_wired = 0; /* XXX max # of wired pages system-wide */ 115 116 117/* 118 * vm_pageout_clean: 119 * cleans a vm_page 120 */ 121int 122vm_pageout_clean(m, sync) 123 register vm_page_t m; 124 int sync; 125{ 126 /* 127 * Clean the page and remove it from the 128 * laundry. 129 * 130 * We set the busy bit to cause 131 * potential page faults on this page to 132 * block. 133 * 134 * And we set pageout-in-progress to keep 135 * the object from disappearing during 136 * pageout. This guarantees that the 137 * page won't move from the inactive 138 * queue. (However, any other page on 139 * the inactive queue may move!) 140 */ 141 142 register vm_object_t object; 143 register vm_pager_t pager; 144 int pageout_status[VM_PAGEOUT_PAGE_COUNT]; 145 vm_page_t ms[VM_PAGEOUT_PAGE_COUNT]; 146 int pageout_count; 147 int anyok=0; 148 int i; 149 vm_offset_t offset = m->offset; 150 151 object = m->object; 152 if (!object) { 153 printf("pager: object missing\n"); 154 return 0; 155 } 156 157 /* 158 * Try to collapse the object before 159 * making a pager for it. We must 160 * unlock the page queues first. 161 * We try to defer the creation of a pager 162 * until all shadows are not paging. This 163 * allows vm_object_collapse to work better and 164 * helps control swap space size. 165 * (J. Dyson 11 Nov 93) 166 */ 167 168 if (!object->pager && 169 cnt.v_free_count < vm_pageout_free_min) 170 return 0; 171 172 if (!object->pager && 173 object->shadow && 174 object->shadow->paging_in_progress) 175 return 0; 176 177 if( !sync) { 178 if (object->shadow) { 179 vm_object_collapse(object); 180 if (!vm_page_lookup(object, offset)) 181 return 0; 182 } 183 184 if ((m->flags & PG_BUSY) || (m->hold_count != 0)) { 185 return 0; 186 } 187 } 188 189 pageout_count = 1; 190 ms[0] = m; 191 192 if( pager = object->pager) { 193 for(i=1;i<VM_PAGEOUT_PAGE_COUNT;i++) { 194 if( ms[i] = vm_page_lookup( object, offset+i*NBPG)) { 195 if((((ms[i]->flags & (PG_CLEAN|PG_INACTIVE|PG_BUSY)) == PG_INACTIVE) 196 || (( ms[i]->flags & PG_CLEAN) == 0 && sync == VM_PAGEOUT_FORCE)) 197 && (ms[i]->wire_count == 0) 198 && (ms[i]->hold_count == 0)) 199 pageout_count++; 200 else 201 break; 202 } else 203 break; 204 } 205 for(i=0;i<pageout_count;i++) { 206 ms[i]->flags |= PG_BUSY; 207 pmap_page_protect(VM_PAGE_TO_PHYS(ms[i]), VM_PROT_READ); 208 } 209 object->paging_in_progress += pageout_count; 210 cnt.v_pageouts += pageout_count; 211 } else { 212 213 m->flags |= PG_BUSY; 214 215 pmap_page_protect(VM_PAGE_TO_PHYS(m), VM_PROT_READ); 216 217 cnt.v_pageouts++; 218 219 object->paging_in_progress++; 220 221 pager = vm_pager_allocate(PG_DFLT, (caddr_t)0, 222 object->size, VM_PROT_ALL, 0); 223 if (pager != NULL) { 224 vm_object_setpager(object, pager, 0, FALSE); 225 } 226 } 227 228 /* 229 * If there is no pager for the page, 230 * use the default pager. If there's 231 * no place to put the page at the 232 * moment, leave it in the laundry and 233 * hope that there will be paging space 234 * later. 235 */ 236 237 if ((pager && pager->pg_type == PG_SWAP) || 238 cnt.v_free_count >= vm_pageout_free_min) { 239 if( pageout_count == 1) { 240 pageout_status[0] = pager ? 241 vm_pager_put(pager, m, 242 ((sync || (object == kernel_object)) ? TRUE: FALSE)) : 243 VM_PAGER_FAIL; 244 } else { 245 if( !pager) { 246 for(i=0;i<pageout_count;i++) 247 pageout_status[i] = VM_PAGER_FAIL; 248 } else { 249 vm_pager_put_pages(pager, ms, pageout_count, 250 ((sync || (object == kernel_object)) ? TRUE : FALSE), 251 pageout_status); 252 } 253 } 254 255 } else { 256 for(i=0;i<pageout_count;i++) 257 pageout_status[i] = VM_PAGER_FAIL; 258 } 259 260 for(i=0;i<pageout_count;i++) { 261 switch (pageout_status[i]) { 262 case VM_PAGER_OK: 263 ms[i]->flags &= ~PG_LAUNDRY; 264 ++anyok; 265 break; 266 case VM_PAGER_PEND: 267 ms[i]->flags &= ~PG_LAUNDRY; 268 ++anyok; 269 break; 270 case VM_PAGER_BAD: 271 /* 272 * Page outside of range of object. 273 * Right now we essentially lose the 274 * changes by pretending it worked. 275 */ 276 ms[i]->flags &= ~PG_LAUNDRY; 277 ms[i]->flags |= PG_CLEAN; 278 pmap_clear_modify(VM_PAGE_TO_PHYS(ms[i])); 279 break; 280 case VM_PAGER_ERROR: 281 case VM_PAGER_FAIL: 282 /* 283 * If page couldn't be paged out, then 284 * reactivate the page so it doesn't 285 * clog the inactive list. (We will 286 * try paging out it again later). 287 */ 288 if (ms[i]->flags & PG_INACTIVE) 289 vm_page_activate(ms[i]); 290 break; 291 case VM_PAGER_AGAIN: 292 break; 293 } 294 295 296 /* 297 * If the operation is still going, leave 298 * the page busy to block all other accesses. 299 * Also, leave the paging in progress 300 * indicator set so that we don't attempt an 301 * object collapse. 302 */ 303 if (pageout_status[i] != VM_PAGER_PEND) { 304 PAGE_WAKEUP(ms[i]); 305 if (--object->paging_in_progress == 0) 306 wakeup((caddr_t) object); 307 if (pmap_is_referenced(VM_PAGE_TO_PHYS(ms[i]))) { 308 pmap_clear_reference(VM_PAGE_TO_PHYS(ms[i])); 309 if( ms[i]->flags & PG_INACTIVE) 310 vm_page_activate(ms[i]); 311 } 312 } 313 } 314 return anyok; 315} 316 317/* 318 * vm_pageout_object_deactivate_pages 319 * 320 * deactivate enough pages to satisfy the inactive target 321 * requirements or if vm_page_proc_limit is set, then 322 * deactivate all of the pages in the object and its 323 * shadows. 324 * 325 * The object and map must be locked. 326 */ 327int 328vm_pageout_object_deactivate_pages(map, object, count) 329 vm_map_t map; 330 vm_object_t object; 331 int count; 332{ 333 register vm_page_t p, next; 334 int rcount; 335 int s; 336 int dcount; 337 338 dcount = 0; 339 if (count == 0) 340 count = 1; 341 342 if (object->shadow) { 343 int scount = count; 344 if( object->shadow->ref_count > 1) 345 scount /= object->shadow->ref_count; 346 if( scount) 347 dcount += vm_pageout_object_deactivate_pages(map, object->shadow, scount); 348 } 349 350 if (object->paging_in_progress) 351 return dcount; 352 353 /* 354 * scan the objects entire memory queue 355 */ 356 rcount = object->resident_page_count; 357 p = object->memq.tqh_first; 358 while (p && (rcount-- > 0)) { 359 next = p->listq.tqe_next; 360 vm_page_lock_queues(); 361 /* 362 * if a page is active, not wired and is in the processes pmap, 363 * then deactivate the page. 364 */ 365 if ((p->flags & (PG_ACTIVE|PG_BUSY)) == PG_ACTIVE && 366 p->wire_count == 0 && 367 p->hold_count == 0 && 368 pmap_page_exists(vm_map_pmap(map), VM_PAGE_TO_PHYS(p))) { 369 if (!pmap_is_referenced(VM_PAGE_TO_PHYS(p))) { 370 p->act_count -= min(p->act_count, ACT_DECLINE); 371 /* 372 * if the page act_count is zero -- then we deactivate 373 */ 374 if (!p->act_count) { 375 vm_page_deactivate(p); 376 pmap_page_protect(VM_PAGE_TO_PHYS(p), 377 VM_PROT_NONE); 378 /* 379 * else if on the next go-around we will deactivate the page 380 * we need to place the page on the end of the queue to age 381 * the other pages in memory. 382 */ 383 } else { 384 TAILQ_REMOVE(&vm_page_queue_active, p, pageq); 385 TAILQ_INSERT_TAIL(&vm_page_queue_active, p, pageq); 386 TAILQ_REMOVE(&object->memq, p, listq); 387 TAILQ_INSERT_TAIL(&object->memq, p, listq); 388 } 389 /* 390 * see if we are done yet 391 */ 392 if (p->flags & PG_INACTIVE) { 393 --count; 394 ++dcount; 395 if (count <= 0 && 396 cnt.v_inactive_count > cnt.v_inactive_target) { 397 vm_page_unlock_queues(); 398 return dcount; 399 } 400 } 401 402 } else { 403 /* 404 * Move the page to the bottom of the queue. 405 */ 406 pmap_clear_reference(VM_PAGE_TO_PHYS(p)); 407 if (p->act_count < ACT_MAX) 408 p->act_count += ACT_ADVANCE; 409 410 TAILQ_REMOVE(&vm_page_queue_active, p, pageq); 411 TAILQ_INSERT_TAIL(&vm_page_queue_active, p, pageq); 412 TAILQ_REMOVE(&object->memq, p, listq); 413 TAILQ_INSERT_TAIL(&object->memq, p, listq); 414 } 415 } 416 417 vm_page_unlock_queues(); 418 p = next; 419 } 420 return dcount; 421} 422 423 424/* 425 * deactivate some number of pages in a map, try to do it fairly, but 426 * that is really hard to do. 427 */ 428 429void 430vm_pageout_map_deactivate_pages(map, entry, count, freeer) 431 vm_map_t map; 432 vm_map_entry_t entry; 433 int *count; 434 int (*freeer)(vm_map_t, vm_object_t, int); 435{ 436 vm_map_t tmpm; 437 vm_map_entry_t tmpe; 438 vm_object_t obj; 439 if (*count <= 0) 440 return; 441 vm_map_reference(map); 442 if (!lock_try_read(&map->lock)) { 443 vm_map_deallocate(map); 444 return; 445 } 446 if (entry == 0) { 447 tmpe = map->header.next; 448 while (tmpe != &map->header && *count > 0) { 449 vm_pageout_map_deactivate_pages(map, tmpe, count, freeer); 450 tmpe = tmpe->next; 451 }; 452 } else if (entry->is_sub_map || entry->is_a_map) { 453 tmpm = entry->object.share_map; 454 tmpe = tmpm->header.next; 455 while (tmpe != &tmpm->header && *count > 0) { 456 vm_pageout_map_deactivate_pages(tmpm, tmpe, count, freeer); 457 tmpe = tmpe->next; 458 }; 459 } else if (obj = entry->object.vm_object) { 460 *count -= (*freeer)(map, obj, *count); 461 } 462 lock_read_done(&map->lock); 463 vm_map_deallocate(map); 464 return; 465} 466 467/* 468 * vm_pageout_scan does the dirty work for the pageout daemon. 469 */ 470int 471vm_pageout_scan() 472{ 473 vm_page_t m; 474 int page_shortage, maxscan, maxlaunder; 475 int pages_freed, free, nproc; 476 int desired_free; 477 vm_page_t next; 478 struct proc *p; 479 vm_object_t object; 480 int s; 481 int force_wakeup = 0; 482 483morefree: 484 /* 485 * scan the processes for exceeding their rlimits or if process 486 * is swapped out -- deactivate pages 487 */ 488 489rescanproc1: 490 for (p = (struct proc *)allproc; p != NULL; p = p->p_next) { 491 vm_offset_t size; 492 int overage; 493 vm_offset_t limit; 494 495 /* 496 * if this is a system process or if we have already 497 * looked at this process, skip it. 498 */ 499 if (p->p_flag & (P_SYSTEM|P_WEXIT)) { 500 continue; 501 } 502 503 /* 504 * if the process is in a non-running type state, 505 * don't touch it. 506 */ 507 if (p->p_stat != SRUN && p->p_stat != SSLEEP) { 508 continue; 509 } 510 511 /* 512 * get a limit 513 */ 514 limit = min(p->p_rlimit[RLIMIT_RSS].rlim_cur, 515 p->p_rlimit[RLIMIT_RSS].rlim_max); 516 517 /* 518 * let processes that are swapped out really be swapped out 519 * set the limit to nothing (will force a swap-out.) 520 */ 521 if ((p->p_flag & P_INMEM) == 0) 522 limit = 0; 523 524 size = p->p_vmspace->vm_pmap.pm_stats.resident_count * NBPG; 525 if (size >= limit) { 526 overage = (size - limit) / NBPG; 527 vm_pageout_map_deactivate_pages(&p->p_vmspace->vm_map, 528 (vm_map_entry_t) 0, &overage, vm_pageout_object_deactivate_pages); 529 } 530 531 } 532 533 if (((cnt.v_free_count + cnt.v_inactive_count) >= 534 (cnt.v_inactive_target + cnt.v_free_target)) && 535 (cnt.v_free_count >= cnt.v_free_target)) 536 return force_wakeup; 537 538 pages_freed = 0; 539 desired_free = cnt.v_free_target; 540 541 /* 542 * Start scanning the inactive queue for pages we can free. 543 * We keep scanning until we have enough free pages or 544 * we have scanned through the entire queue. If we 545 * encounter dirty pages, we start cleaning them. 546 */ 547 548 maxlaunder = (cnt.v_free_target - cnt.v_free_count); 549 maxscan = cnt.v_inactive_count; 550rescan1: 551 m = vm_page_queue_inactive.tqh_first; 552 while (m && (maxscan-- > 0) && 553 (cnt.v_free_count < desired_free) ) { 554 vm_page_t next; 555 556 next = m->pageq.tqe_next; 557 558 if( (m->flags & PG_INACTIVE) == 0) { 559 printf("vm_pageout_scan: page not inactive?"); 560 continue; 561 } 562 563 /* 564 * activate held pages 565 */ 566 if (m->hold_count != 0) { 567 vm_page_activate(m); 568 m = next; 569 continue; 570 } 571 572 /* 573 * dont mess with busy pages 574 */ 575 if (m->flags & PG_BUSY) { 576 m = next; 577 continue; 578 } 579 580 /* 581 * if page is clean and but the page has been referenced, 582 * then reactivate the page, but if we are very low on memory 583 * or the page has not been referenced, then we free it to the 584 * vm system. 585 */ 586 if (m->flags & PG_CLEAN) { 587 if ((cnt.v_free_count > vm_pageout_free_min) /* XXX */ 588 && pmap_is_referenced(VM_PAGE_TO_PHYS(m))) { 589 vm_page_activate(m); 590 } else if (!m->act_count) { 591 pmap_page_protect(VM_PAGE_TO_PHYS(m), 592 VM_PROT_NONE); 593 vm_page_free(m); 594 ++pages_freed; 595 } else { 596 m->act_count -= min(m->act_count, ACT_DECLINE); 597 TAILQ_REMOVE(&vm_page_queue_inactive, m, pageq); 598 TAILQ_INSERT_TAIL(&vm_page_queue_inactive, m, pageq); 599 } 600 } else if ((m->flags & PG_LAUNDRY) && maxlaunder > 0) { 601 int written; 602 if (pmap_is_referenced(VM_PAGE_TO_PHYS(m))) { 603 pmap_clear_reference(VM_PAGE_TO_PHYS(m)); 604 vm_page_activate(m); 605 m = next; 606 continue; 607 } 608 /* 609 * If a page is dirty, then it is either 610 * being washed (but not yet cleaned) 611 * or it is still in the laundry. If it is 612 * still in the laundry, then we start the 613 * cleaning operation. 614 */ 615 616 if (written = vm_pageout_clean(m,0)) { 617 maxlaunder -= written; 618 } 619 /* 620 * if the next page has been re-activated, start scanning again 621 */ 622 if (next && (next->flags & PG_INACTIVE) == 0) 623 goto rescan1; 624 } else if (pmap_is_referenced(VM_PAGE_TO_PHYS(m))) { 625 pmap_clear_reference(VM_PAGE_TO_PHYS(m)); 626 vm_page_activate(m); 627 } 628 m = next; 629 } 630 631 /* 632 * now check malloc area or swap processes out if we are in low 633 * memory conditions 634 */ 635 if (cnt.v_free_count <= cnt.v_free_min) { 636 /* 637 * swap out inactive processes 638 */ 639 swapout_threads(); 640 } 641 642 /* 643 * Compute the page shortage. If we are still very low on memory 644 * be sure that we will move a minimal amount of pages from active 645 * to inactive. 646 */ 647 648 page_shortage = cnt.v_inactive_target - 649 (cnt.v_free_count + cnt.v_inactive_count); 650 651 if (page_shortage <= 0) { 652 if (pages_freed == 0) { 653 if( cnt.v_free_count < cnt.v_free_min) { 654 page_shortage = cnt.v_free_min - cnt.v_free_count; 655 } else if(((cnt.v_free_count + cnt.v_inactive_count) < 656 (cnt.v_free_min + cnt.v_inactive_target))) { 657 page_shortage = 1; 658 } else { 659 page_shortage = 0; 660 } 661 } 662 663 } 664 665 maxscan = cnt.v_active_count; 666 m = vm_page_queue_active.tqh_first; 667 while (m && maxscan-- && (page_shortage > 0)) { 668 669 next = m->pageq.tqe_next; 670 671 /* 672 * Don't deactivate pages that are busy. 673 */ 674 if ((m->flags & PG_BUSY) || (m->hold_count != 0)) { 675 m = next; 676 continue; 677 } 678 679 if (pmap_is_referenced(VM_PAGE_TO_PHYS(m))) { 680 pmap_clear_reference(VM_PAGE_TO_PHYS(m)); 681 if (m->act_count < ACT_MAX) 682 m->act_count += ACT_ADVANCE; 683 TAILQ_REMOVE(&vm_page_queue_active, m, pageq); 684 TAILQ_INSERT_TAIL(&vm_page_queue_active, m, pageq); 685 TAILQ_REMOVE(&m->object->memq, m, listq); 686 TAILQ_INSERT_TAIL(&m->object->memq, m, listq); 687 } else { 688 m->act_count -= min(m->act_count, ACT_DECLINE); 689 690 /* 691 * if the page act_count is zero -- then we deactivate 692 */ 693 if (!m->act_count) { 694 vm_page_deactivate(m); 695 --page_shortage; 696 /* 697 * else if on the next go-around we will deactivate the page 698 * we need to place the page on the end of the queue to age 699 * the other pages in memory. 700 */ 701 } else { 702 TAILQ_REMOVE(&vm_page_queue_active, m, pageq); 703 TAILQ_INSERT_TAIL(&vm_page_queue_active, m, pageq); 704 TAILQ_REMOVE(&m->object->memq, m, listq); 705 TAILQ_INSERT_TAIL(&m->object->memq, m, listq); 706 } 707 } 708 709 m = next; 710 } 711 712 /* 713 * if we have not freed any pages and we are desparate for memory 714 * then we keep trying until we get some (any) memory. 715 */ 716 717 if( !force_wakeup && (swap_pager_full || !force_wakeup || 718 (pages_freed == 0 && (cnt.v_free_count < cnt.v_free_min)))){ 719 vm_pager_sync(); 720 force_wakeup = 1; 721 goto morefree; 722 } 723 vm_page_pagesfreed += pages_freed; 724 return force_wakeup; 725} 726 727/* 728 * vm_pageout is the high level pageout daemon. 729 */ 730void 731vm_pageout() 732{ 733 extern npendingio, swiopend; 734 static nowakeup; 735 (void) spl0(); 736 737 /* 738 * Initialize some paging parameters. 739 */ 740 741vmretry: 742 cnt.v_free_min = 12; 743 cnt.v_free_reserved = 8; 744 if (cnt.v_free_min < 8) 745 cnt.v_free_min = 8; 746 if (cnt.v_free_min > 32) 747 cnt.v_free_min = 32; 748 vm_pageout_free_min = 4; 749 cnt.v_free_target = 2*cnt.v_free_min + cnt.v_free_reserved; 750 cnt.v_inactive_target = cnt.v_free_count / 12; 751 cnt.v_free_min += cnt.v_free_reserved; 752 753 /* XXX does not really belong here */ 754 if (vm_page_max_wired == 0) 755 vm_page_max_wired = cnt.v_free_count / 3; 756 757 758 (void) swap_pager_alloc(0, 0, 0, 0); 759 760 /* 761 * The pageout daemon is never done, so loop 762 * forever. 763 */ 764 while (TRUE) { 765 int force_wakeup; 766 extern struct loadavg averunnable; 767/* 768 cnt.v_free_min = 12 + averunnable.ldavg[0] / 1024; 769 cnt.v_free_target = 2*cnt.v_free_min + cnt.v_free_reserved; 770 cnt.v_inactive_target = cnt.v_free_target*2; 771*/ 772 773 tsleep((caddr_t) &vm_pages_needed, PVM, "psleep", 0); 774 775 vm_pager_sync(); 776 /* 777 * The force wakeup hack added to eliminate delays and potiential 778 * deadlock. It was possible for the page daemon to indefintely 779 * postpone waking up a process that it might be waiting for memory 780 * on. The putmulti stuff seems to have aggravated the situation. 781 */ 782 force_wakeup = vm_pageout_scan(); 783 vm_pager_sync(); 784 if( force_wakeup) 785 wakeup( (caddr_t) &cnt.v_free_count); 786 cnt.v_scan++; 787 wakeup((caddr_t) kmem_map); 788 } 789} 790 791