vm_pageout.c revision 4810
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 * from: @(#)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 1.26 1994/11/17 06:24:25 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#include <vm/swap_pager.h> 85 86extern vm_map_t kmem_map; 87int vm_pages_needed; /* Event on which pageout daemon sleeps */ 88int vm_pagescanner; /* Event on which pagescanner sleeps */ 89int vm_pageout_free_min = 0; /* Stop pageout to wait for pagers at this free level */ 90 91int vm_pageout_pages_needed = 0; /* flag saying that the pageout daemon needs pages */ 92int vm_page_pagesfreed; 93int vm_desired_cache_size; 94 95extern int npendingio; 96extern int hz; 97int vm_pageout_proc_limit; 98int vm_pageout_req_swapout; 99int vm_daemon_needed; 100extern int nswiodone; 101extern int swap_pager_full; 102extern int vm_swap_size; 103extern int swap_pager_ready(); 104 105#define MAXREF 32767 106 107#define MAXSCAN 512 /* maximum number of pages to scan in active queue */ 108 /* set the "clock" hands to be (MAXSCAN * 4096) Bytes */ 109#define ACT_DECLINE 1 110#define ACT_ADVANCE 3 111#define ACT_MAX 100 112 113#define LOWATER ((2048*1024)/NBPG) 114 115#define VM_PAGEOUT_PAGE_COUNT 8 116int vm_pageout_page_count = VM_PAGEOUT_PAGE_COUNT; 117int vm_pageout_req_do_stats; 118 119int vm_page_max_wired = 0; /* XXX max # of wired pages system-wide */ 120 121 122/* 123 * vm_pageout_clean: 124 * cleans a vm_page 125 */ 126int 127vm_pageout_clean(m, sync) 128 register vm_page_t m; 129 int sync; 130{ 131 /* 132 * Clean the page and remove it from the 133 * laundry. 134 * 135 * We set the busy bit to cause 136 * potential page faults on this page to 137 * block. 138 * 139 * And we set pageout-in-progress to keep 140 * the object from disappearing during 141 * pageout. This guarantees that the 142 * page won't move from the inactive 143 * queue. (However, any other page on 144 * the inactive queue may move!) 145 */ 146 147 register vm_object_t object; 148 register vm_pager_t pager; 149 int pageout_status[VM_PAGEOUT_PAGE_COUNT]; 150 vm_page_t ms[VM_PAGEOUT_PAGE_COUNT]; 151 int pageout_count; 152 int anyok=0; 153 int i; 154 vm_offset_t offset = m->offset; 155 156 object = m->object; 157 if (!object) { 158 printf("pager: object missing\n"); 159 return 0; 160 } 161 162 /* 163 * Try to collapse the object before 164 * making a pager for it. We must 165 * unlock the page queues first. 166 * We try to defer the creation of a pager 167 * until all shadows are not paging. This 168 * allows vm_object_collapse to work better and 169 * helps control swap space size. 170 * (J. Dyson 11 Nov 93) 171 */ 172 173 if (!object->pager && 174 cnt.v_free_count < vm_pageout_free_min) 175 return 0; 176 177 if( !sync) { 178 if (object->shadow) { 179 vm_object_collapse(object); 180 } 181 182 if ((m->busy != 0) || 183 (m->flags & PG_BUSY) || (m->hold_count != 0)) { 184 return 0; 185 } 186 } 187 188 pageout_count = 1; 189 ms[0] = m; 190 191 pager = object->pager; 192 if (pager) { 193 for (i = 1; i < vm_pageout_page_count; i++) { 194 ms[i] = vm_page_lookup(object, offset+i*NBPG); 195 if (ms[i]) { 196 if (((ms[i]->flags & PG_CLEAN) != 0) && 197 pmap_is_modified(VM_PAGE_TO_PHYS(ms[i]))) { 198 ms[i]->flags &= ~PG_CLEAN; 199 } 200 if (( ((ms[i]->flags & (PG_CLEAN|PG_INACTIVE|PG_BUSY)) == PG_INACTIVE) 201 || ( (ms[i]->flags & (PG_CLEAN|PG_BUSY)) == 0 && sync == VM_PAGEOUT_FORCE)) 202 && (ms[i]->wire_count == 0) 203 && (ms[i]->busy == 0) 204 && (ms[i]->hold_count == 0)) 205 pageout_count++; 206 else 207 break; 208 } else 209 break; 210 } 211 for(i=0;i<pageout_count;i++) { 212 ms[i]->flags |= PG_BUSY; 213 pmap_page_protect(VM_PAGE_TO_PHYS(ms[i]), VM_PROT_READ); 214 } 215 object->paging_in_progress += pageout_count; 216 } else { 217 218 m->flags |= PG_BUSY; 219 220 pmap_page_protect(VM_PAGE_TO_PHYS(m), VM_PROT_READ); 221 222 object->paging_in_progress++; 223 224 pager = vm_pager_allocate(PG_DFLT, (caddr_t)0, 225 object->size, VM_PROT_ALL, 0); 226 if (pager != NULL) { 227 vm_object_setpager(object, pager, 0, FALSE); 228 } 229 } 230 231 /* 232 * If there is no pager for the page, 233 * use the default pager. If there's 234 * no place to put the page at the 235 * moment, leave it in the laundry and 236 * hope that there will be paging space 237 * later. 238 */ 239 240 if ((pager && pager->pg_type == PG_SWAP) || 241 cnt.v_free_count >= vm_pageout_free_min) { 242 if( pageout_count == 1) { 243 pageout_status[0] = pager ? 244 vm_pager_put(pager, m, 245 ((sync || (object == kernel_object)) ? TRUE: FALSE)) : 246 VM_PAGER_FAIL; 247 } else { 248 if( !pager) { 249 for(i=0;i<pageout_count;i++) 250 pageout_status[i] = VM_PAGER_FAIL; 251 } else { 252 vm_pager_put_pages(pager, ms, pageout_count, 253 ((sync || (object == kernel_object)) ? TRUE : FALSE), 254 pageout_status); 255 } 256 } 257 258 } else { 259 for(i=0;i<pageout_count;i++) 260 pageout_status[i] = VM_PAGER_FAIL; 261 } 262 263 for(i=0;i<pageout_count;i++) { 264 switch (pageout_status[i]) { 265 case VM_PAGER_OK: 266 ms[i]->flags &= ~PG_LAUNDRY; 267 ++anyok; 268 break; 269 case VM_PAGER_PEND: 270 ms[i]->flags &= ~PG_LAUNDRY; 271 ++anyok; 272 break; 273 case VM_PAGER_BAD: 274 /* 275 * Page outside of range of object. 276 * Right now we essentially lose the 277 * changes by pretending it worked. 278 */ 279 ms[i]->flags &= ~PG_LAUNDRY; 280 ms[i]->flags |= PG_CLEAN; 281 pmap_clear_modify(VM_PAGE_TO_PHYS(ms[i])); 282 break; 283 case VM_PAGER_ERROR: 284 case VM_PAGER_FAIL: 285 /* 286 * If page couldn't be paged out, then 287 * reactivate the page so it doesn't 288 * clog the inactive list. (We will 289 * try paging out it again later). 290 */ 291 if (ms[i]->flags & PG_INACTIVE) 292 vm_page_activate(ms[i]); 293 break; 294 case VM_PAGER_AGAIN: 295 break; 296 } 297 298 299 /* 300 * If the operation is still going, leave 301 * the page busy to block all other accesses. 302 * Also, leave the paging in progress 303 * indicator set so that we don't attempt an 304 * object collapse. 305 */ 306 if (pageout_status[i] != VM_PAGER_PEND) { 307 PAGE_WAKEUP(ms[i]); 308 if (--object->paging_in_progress == 0) 309 wakeup((caddr_t) object); 310 if ((ms[i]->flags & PG_REFERENCED) || 311 pmap_is_referenced(VM_PAGE_TO_PHYS(ms[i]))) { 312 pmap_clear_reference(VM_PAGE_TO_PHYS(ms[i])); 313 ms[i]->flags &= ~PG_REFERENCED; 314 if( ms[i]->flags & PG_INACTIVE) 315 vm_page_activate(ms[i]); 316 } 317 } 318 } 319 return anyok; 320} 321 322/* 323 * vm_pageout_object_deactivate_pages 324 * 325 * deactivate enough pages to satisfy the inactive target 326 * requirements or if vm_page_proc_limit is set, then 327 * deactivate all of the pages in the object and its 328 * shadows. 329 * 330 * The object and map must be locked. 331 */ 332int 333vm_pageout_object_deactivate_pages(map, object, count) 334 vm_map_t map; 335 vm_object_t object; 336 int count; 337{ 338 register vm_page_t p, next; 339 int rcount; 340 int dcount; 341 342 dcount = 0; 343 if (count == 0) 344 count = 1; 345 346 if (object->shadow) { 347 if( object->shadow->ref_count == 1) 348 dcount += vm_pageout_object_deactivate_pages(map, object->shadow, count/2); 349 } 350 351 if (object->paging_in_progress) 352 return dcount; 353 354 /* 355 * scan the objects entire memory queue 356 */ 357 rcount = object->resident_page_count; 358 p = object->memq.tqh_first; 359 while (p && (rcount-- > 0)) { 360 next = p->listq.tqe_next; 361 cnt.v_pdpages++; 362 vm_page_lock_queues(); 363 /* 364 * if a page is active, not wired and is in the processes pmap, 365 * then deactivate the page. 366 */ 367 if ((p->flags & (PG_ACTIVE|PG_BUSY)) == PG_ACTIVE && 368 p->wire_count == 0 && 369 p->hold_count == 0 && 370 p->busy == 0 && 371 pmap_page_exists(vm_map_pmap(map), VM_PAGE_TO_PHYS(p))) { 372 if (!pmap_is_referenced(VM_PAGE_TO_PHYS(p)) && 373 (p->flags & PG_REFERENCED) == 0) { 374 p->act_count -= min(p->act_count, ACT_DECLINE); 375 /* 376 * if the page act_count is zero -- then we deactivate 377 */ 378 if (!p->act_count) { 379 vm_page_deactivate(p); 380 pmap_page_protect(VM_PAGE_TO_PHYS(p), 381 VM_PROT_NONE); 382 /* 383 * else if on the next go-around we will deactivate the page 384 * we need to place the page on the end of the queue to age 385 * the other pages in memory. 386 */ 387 } else { 388 TAILQ_REMOVE(&vm_page_queue_active, p, pageq); 389 TAILQ_INSERT_TAIL(&vm_page_queue_active, p, pageq); 390 TAILQ_REMOVE(&object->memq, p, listq); 391 TAILQ_INSERT_TAIL(&object->memq, p, listq); 392 } 393 /* 394 * see if we are done yet 395 */ 396 if (p->flags & PG_INACTIVE) { 397 --count; 398 ++dcount; 399 if (count <= 0 && 400 cnt.v_inactive_count > cnt.v_inactive_target) { 401 vm_page_unlock_queues(); 402 return dcount; 403 } 404 } 405 406 } else { 407 /* 408 * Move the page to the bottom of the queue. 409 */ 410 pmap_clear_reference(VM_PAGE_TO_PHYS(p)); 411 p->flags &= ~PG_REFERENCED; 412 if (p->act_count < ACT_MAX) 413 p->act_count += ACT_ADVANCE; 414 415 TAILQ_REMOVE(&vm_page_queue_active, p, pageq); 416 TAILQ_INSERT_TAIL(&vm_page_queue_active, p, pageq); 417 TAILQ_REMOVE(&object->memq, p, listq); 418 TAILQ_INSERT_TAIL(&object->memq, p, listq); 419 } 420 } 421 422 vm_page_unlock_queues(); 423 p = next; 424 } 425 return dcount; 426} 427 428 429/* 430 * deactivate some number of pages in a map, try to do it fairly, but 431 * that is really hard to do. 432 */ 433 434void 435vm_pageout_map_deactivate_pages(map, entry, count, freeer) 436 vm_map_t map; 437 vm_map_entry_t entry; 438 int *count; 439 int (*freeer)(vm_map_t, vm_object_t, int); 440{ 441 vm_map_t tmpm; 442 vm_map_entry_t tmpe; 443 vm_object_t obj; 444 if (*count <= 0) 445 return; 446 vm_map_reference(map); 447 if (!lock_try_read(&map->lock)) { 448 vm_map_deallocate(map); 449 return; 450 } 451 if (entry == 0) { 452 tmpe = map->header.next; 453 while (tmpe != &map->header && *count > 0) { 454 vm_pageout_map_deactivate_pages(map, tmpe, count, freeer); 455 tmpe = tmpe->next; 456 }; 457 } else if (entry->is_sub_map || entry->is_a_map) { 458 tmpm = entry->object.share_map; 459 tmpe = tmpm->header.next; 460 while (tmpe != &tmpm->header && *count > 0) { 461 vm_pageout_map_deactivate_pages(tmpm, tmpe, count, freeer); 462 tmpe = tmpe->next; 463 }; 464 } else if ((obj = entry->object.vm_object) != 0) { 465 *count -= (*freeer)(map, obj, *count); 466 } 467 lock_read_done(&map->lock); 468 vm_map_deallocate(map); 469 return; 470} 471 472void 473vm_req_vmdaemon() { 474 extern int ticks; 475 static lastrun = 0; 476 if( (ticks > (lastrun + hz/10)) || (ticks < lastrun)) { 477 wakeup((caddr_t) &vm_daemon_needed); 478 lastrun = ticks; 479 } 480} 481 482/* 483 * vm_pageout_scan does the dirty work for the pageout daemon. 484 */ 485int 486vm_pageout_scan() 487{ 488 vm_page_t m; 489 int page_shortage, maxscan, maxlaunder; 490 int pages_freed; 491 int desired_free; 492 vm_page_t next; 493 struct proc *p, *bigproc; 494 vm_offset_t size, bigsize; 495 vm_object_t object; 496 int force_wakeup = 0; 497 int cache_size, orig_cache_size; 498 499 /* calculate the total cached size */ 500 501 if( cnt.v_inactive_count < cnt.v_inactive_target) { 502 vm_req_vmdaemon(); 503 } 504 505morefree: 506 /* 507 * now swap processes out if we are in low memory conditions 508 */ 509 if ((cnt.v_free_count <= cnt.v_free_min) && !swap_pager_full && vm_swap_size&& vm_pageout_req_swapout == 0) { 510 vm_pageout_req_swapout = 1; 511 vm_req_vmdaemon(); 512 } 513 514 pages_freed = 0; 515 desired_free = cnt.v_free_target; 516 517 /* 518 * Start scanning the inactive queue for pages we can free. 519 * We keep scanning until we have enough free pages or 520 * we have scanned through the entire queue. If we 521 * encounter dirty pages, we start cleaning them. 522 */ 523 524 maxlaunder = 128; 525 maxscan = cnt.v_inactive_count; 526rescan1: 527 m = vm_page_queue_inactive.tqh_first; 528 while (m && (maxscan-- > 0) && 529 (cnt.v_free_count < desired_free) ) { 530 vm_page_t next; 531 532 cnt.v_pdpages++; 533 next = m->pageq.tqe_next; 534 535 if( (m->flags & PG_INACTIVE) == 0) { 536 printf("vm_pageout_scan: page not inactive?"); 537 continue; 538 } 539 540 /* 541 * activate held pages 542 */ 543 if (m->hold_count != 0) { 544 vm_page_activate(m); 545 m = next; 546 continue; 547 } 548 549 /* 550 * dont mess with busy pages 551 */ 552 if (m->busy || (m->flags & PG_BUSY)) { 553 m = next; 554 continue; 555 } 556 557 if (((m->flags & PG_CLEAN) != 0) && pmap_is_modified(VM_PAGE_TO_PHYS(m))) { 558 m->flags &= ~PG_CLEAN; 559 m->flags |= PG_LAUNDRY; 560 } 561 562 if (((m->flags & PG_REFERENCED) == 0) && pmap_is_referenced(VM_PAGE_TO_PHYS(m))) { 563 m->flags |= PG_REFERENCED; 564 pmap_clear_reference(VM_PAGE_TO_PHYS(m)); 565 } 566 567 if (m->flags & PG_CLEAN) { 568 /* 569 * If we're not low on memory and the page has been reference, 570 * then reactivate the page. 571 */ 572 if ((cnt.v_free_count > vm_pageout_free_min) && 573 ((m->flags & PG_REFERENCED) != 0)) { 574 m->flags &= ~PG_REFERENCED; 575 vm_page_activate(m); 576 } else if (m->act_count == 0) { 577 pmap_page_protect(VM_PAGE_TO_PHYS(m), 578 VM_PROT_NONE); 579 vm_page_free(m); 580 ++cnt.v_dfree; 581 ++pages_freed; 582 } else { 583 m->act_count -= min(m->act_count, ACT_DECLINE); 584 TAILQ_REMOVE(&vm_page_queue_inactive, m, pageq); 585 TAILQ_INSERT_TAIL(&vm_page_queue_inactive, m, pageq); 586 } 587 } else if ((m->flags & PG_LAUNDRY) && maxlaunder > 0) { 588 int written; 589 if ((m->flags & PG_REFERENCED) != 0) { 590 m->flags &= ~PG_REFERENCED; 591 vm_page_activate(m); 592 m = next; 593 continue; 594 } 595 596 /* 597 * If a page is dirty, then it is either 598 * being washed (but not yet cleaned) 599 * or it is still in the laundry. If it is 600 * still in the laundry, then we start the 601 * cleaning operation. 602 */ 603 written = vm_pageout_clean(m,0); 604 if (written) 605 maxlaunder -= written; 606 607 if (!next) 608 break; 609 /* 610 * if the next page has been re-activated, start scanning again 611 */ 612 if ((written != 0) || ((next->flags & PG_INACTIVE) == 0)) 613 goto rescan1; 614 } else if ((m->flags & PG_REFERENCED) != 0) { 615 m->flags &= ~PG_REFERENCED; 616 vm_page_activate(m); 617 } 618 m = next; 619 } 620 621 /* 622 * Compute the page shortage. If we are still very low on memory 623 * be sure that we will move a minimal amount of pages from active 624 * to inactive. 625 */ 626 627 page_shortage = cnt.v_inactive_target - 628 (cnt.v_free_count + cnt.v_inactive_count); 629 630 if (page_shortage <= 0) { 631 if (pages_freed == 0) { 632 if( cnt.v_free_count < cnt.v_free_min) { 633 page_shortage = cnt.v_free_min - cnt.v_free_count + 1; 634 } else if(((cnt.v_free_count + cnt.v_inactive_count) < 635 (cnt.v_free_min + cnt.v_inactive_target))) { 636 page_shortage = 1; 637 } else { 638 page_shortage = 0; 639 } 640 } 641 642 } 643 644 maxscan = cnt.v_active_count; 645 m = vm_page_queue_active.tqh_first; 646 while (m && maxscan-- && (page_shortage > 0)) { 647 648 cnt.v_pdpages++; 649 next = m->pageq.tqe_next; 650 651 /* 652 * Don't deactivate pages that are busy. 653 */ 654 if ((m->busy != 0) || 655 (m->flags & PG_BUSY) || (m->hold_count != 0)) { 656 m = next; 657 continue; 658 } 659 660 if ((m->flags & PG_REFERENCED) || 661 pmap_is_referenced(VM_PAGE_TO_PHYS(m))) { 662 pmap_clear_reference(VM_PAGE_TO_PHYS(m)); 663 m->flags &= ~PG_REFERENCED; 664 if (m->act_count < ACT_MAX) 665 m->act_count += ACT_ADVANCE; 666 TAILQ_REMOVE(&vm_page_queue_active, m, pageq); 667 TAILQ_INSERT_TAIL(&vm_page_queue_active, m, pageq); 668 TAILQ_REMOVE(&m->object->memq, m, listq); 669 TAILQ_INSERT_TAIL(&m->object->memq, m, listq); 670 } else { 671 m->act_count -= min(m->act_count, ACT_DECLINE); 672 673 /* 674 * if the page act_count is zero -- then we deactivate 675 */ 676 if (!m->act_count) { 677 vm_page_deactivate(m); 678 --page_shortage; 679 /* 680 * else if on the next go-around we will deactivate the page 681 * we need to place the page on the end of the queue to age 682 * the other pages in memory. 683 */ 684 } else { 685 TAILQ_REMOVE(&vm_page_queue_active, m, pageq); 686 TAILQ_INSERT_TAIL(&vm_page_queue_active, m, pageq); 687 TAILQ_REMOVE(&m->object->memq, m, listq); 688 TAILQ_INSERT_TAIL(&m->object->memq, m, listq); 689 } 690 } 691 m = next; 692 } 693 694 /* 695 * if we have not freed any pages and we are desparate for memory 696 * then we keep trying until we get some (any) memory. 697 */ 698 699 if (!force_wakeup && (swap_pager_full || !force_wakeup || 700 (pages_freed == 0 && (cnt.v_free_count < cnt.v_free_min)))){ 701 vm_pager_sync(); 702 force_wakeup = 1; 703 goto morefree; 704 } 705 706 /* 707 * make sure that we have swap space -- if we are low on 708 * memory and swap -- then kill the biggest process. 709 */ 710 if ((vm_swap_size == 0 || swap_pager_full) && 711 (cnt.v_free_count < cnt.v_free_min)) { 712 bigproc = NULL; 713 bigsize = 0; 714 for (p = (struct proc *)allproc; p != NULL; p = p->p_next) { 715 /* 716 * if this is a system process, skip it 717 */ 718 if ((p->p_flag & P_SYSTEM) || (p->p_pid == 1) || 719 ((p->p_pid < 48) && (vm_swap_size != 0))) { 720 continue; 721 } 722 723 /* 724 * if the process is in a non-running type state, 725 * don't touch it. 726 */ 727 if (p->p_stat != SRUN && p->p_stat != SSLEEP) { 728 continue; 729 } 730 /* 731 * get the process size 732 */ 733 size = p->p_vmspace->vm_pmap.pm_stats.resident_count; 734 /* 735 * if the this process is bigger than the biggest one 736 * remember it. 737 */ 738 if (size > bigsize) { 739 bigproc = p; 740 bigsize = size; 741 } 742 } 743 if (bigproc != NULL) { 744 printf("Process %lu killed by vm_pageout -- out of swap\n", (u_long)bigproc->p_pid); 745 psignal(bigproc, SIGKILL); 746 bigproc->p_estcpu = 0; 747 bigproc->p_nice = PRIO_MIN; 748 resetpriority(bigproc); 749 wakeup( (caddr_t) &cnt.v_free_count); 750 } 751 } 752 vm_page_pagesfreed += pages_freed; 753 return force_wakeup; 754} 755 756/* 757 * vm_pageout is the high level pageout daemon. 758 */ 759void 760vm_pageout() 761{ 762 (void) spl0(); 763 764 /* 765 * Initialize some paging parameters. 766 */ 767 768 cnt.v_free_min = 12; 769 /* 770 * free_reserved needs to include enough for the largest 771 * swap pager structures plus enough for any pv_entry 772 * structs when paging. 773 */ 774 vm_pageout_free_min = 4 + cnt.v_page_count / 1024; 775 cnt.v_free_reserved = vm_pageout_free_min + 2; 776 if (cnt.v_free_min < 8) 777 cnt.v_free_min = 8; 778 if (cnt.v_free_min > 32) 779 cnt.v_free_min = 32; 780 cnt.v_free_target = 2*cnt.v_free_min + cnt.v_free_reserved; 781 cnt.v_inactive_target = cnt.v_free_count / 12; 782 cnt.v_free_min += cnt.v_free_reserved; 783 vm_desired_cache_size = cnt.v_page_count / 3; 784 785 /* XXX does not really belong here */ 786 if (vm_page_max_wired == 0) 787 vm_page_max_wired = cnt.v_free_count / 3; 788 789 790 (void) swap_pager_alloc(0, 0, 0, 0); 791 792 /* 793 * The pageout daemon is never done, so loop 794 * forever. 795 */ 796 while (TRUE) { 797 int force_wakeup; 798 799 tsleep((caddr_t) &vm_pages_needed, PVM, "psleep", 0); 800 cnt.v_pdwakeups++; 801 802 vm_pager_sync(); 803 /* 804 * The force wakeup hack added to eliminate delays and potiential 805 * deadlock. It was possible for the page daemon to indefintely 806 * postpone waking up a process that it might be waiting for memory 807 * on. The putmulti stuff seems to have aggravated the situation. 808 */ 809 force_wakeup = vm_pageout_scan(); 810 vm_pager_sync(); 811 if( force_wakeup) 812 wakeup( (caddr_t) &cnt.v_free_count); 813 wakeup((caddr_t) kmem_map); 814 } 815} 816 817void 818vm_daemon() { 819 int cache_size; 820 vm_object_t object; 821 struct proc *p; 822 while(TRUE) { 823 tsleep((caddr_t) &vm_daemon_needed, PUSER, "psleep", 0); 824 if( vm_pageout_req_swapout) { 825 /* 826 * swap out inactive processes 827 */ 828 swapout_threads(); 829 vm_pageout_req_swapout = 0; 830 } 831 /* 832 * scan the processes for exceeding their rlimits or if process 833 * is swapped out -- deactivate pages 834 */ 835 836 for (p = (struct proc *)allproc; p != NULL; p = p->p_next) { 837 int overage; 838 quad_t limit; 839 vm_offset_t size; 840 841 /* 842 * if this is a system process or if we have already 843 * looked at this process, skip it. 844 */ 845 if (p->p_flag & (P_SYSTEM|P_WEXIT)) { 846 continue; 847 } 848 849 /* 850 * if the process is in a non-running type state, 851 * don't touch it. 852 */ 853 if (p->p_stat != SRUN && p->p_stat != SSLEEP) { 854 continue; 855 } 856 857 /* 858 * get a limit 859 */ 860 limit = qmin(p->p_rlimit[RLIMIT_RSS].rlim_cur, 861 p->p_rlimit[RLIMIT_RSS].rlim_max); 862 863 /* 864 * let processes that are swapped out really be swapped out 865 * set the limit to nothing (will force a swap-out.) 866 */ 867 if ((p->p_flag & P_INMEM) == 0) 868 limit = 0; 869 870 size = p->p_vmspace->vm_pmap.pm_stats.resident_count * NBPG; 871 if (limit >= 0 && size >= limit) { 872 overage = (size - limit) / NBPG; 873 vm_pageout_map_deactivate_pages(&p->p_vmspace->vm_map, 874 (vm_map_entry_t) 0, &overage, vm_pageout_object_deactivate_pages); 875 } 876 } 877 878 /* 879 * We manage the cached memory by attempting to keep it 880 * at about the desired level. 881 * We deactivate the pages for the oldest cached objects 882 * first. This keeps pages that are "cached" from hogging 883 * physical memory. 884 */ 885restart: 886 cache_size = 0; 887 object = vm_object_cached_list.tqh_first; 888 /* calculate the total cached size */ 889 while( object) { 890 cache_size += object->resident_page_count; 891 object = object->cached_list.tqe_next; 892 } 893 894 vm_object_cache_lock(); 895 object = vm_object_cached_list.tqh_first; 896 while ( object) { 897 vm_object_cache_unlock(); 898 /* 899 * if there are no resident pages -- get rid of the object 900 */ 901 if( object->resident_page_count == 0) { 902 if (object != vm_object_lookup(object->pager)) 903 panic("vm_object_cache_trim: I'm sooo confused."); 904 pager_cache(object, FALSE); 905 goto restart; 906 } else if( cache_size >= (vm_swap_size?vm_desired_cache_size:0)) { 907 /* 908 * if there are resident pages -- deactivate them 909 */ 910 vm_object_deactivate_pages(object); 911 cache_size -= object->resident_page_count; 912 } 913 object = object->cached_list.tqe_next; 914 vm_object_cache_lock(); 915 } 916 vm_object_cache_unlock(); 917 } 918} 919