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 * $FreeBSD$ 69 */ 70 71 /* 72 * The proverbial page-out daemon. 73 */ 74 75 #include "opt_vm.h" 76 #include <sys/param.h> 77 #include <sys/systm.h> 78 #include <sys/kernel.h> 79 #include <sys/proc.h> 80 #include <sys/kthread.h> 81 #include <sys/resourcevar.h> 82 #include <sys/signalvar.h> 83 #include <sys/vnode.h> 84 #include <sys/vmmeter.h> 85 #include <sys/sysctl.h> 86 87 #include <vm/vm.h> 88 #include <vm/vm_param.h> 89 #include <sys/lock.h> 90 #include <vm/vm_object.h> 91 #include <vm/vm_page.h> 92 #include <vm/vm_map.h> 93 #include <vm/vm_pageout.h> 94 #include <vm/vm_pager.h> 95 #include <vm/swap_pager.h> 96 #include <vm/vm_extern.h> 97 98 /* 99 * System initialization 100 */ 101 102 /* the kernel process "vm_pageout"*/ 103 static void vm_pageout __P((void)); 104 static int vm_pageout_clean __P((vm_page_t)); 105 static int vm_pageout_scan __P((void)); 106 static int vm_pageout_free_page_calc __P((vm_size_t count)); 107 struct proc *pageproc; 108 109 static struct kproc_desc page_kp = { 110 "pagedaemon", 111 vm_pageout, 112 &pageproc 113 }; 114 SYSINIT(pagedaemon, SI_SUB_KTHREAD_PAGE, SI_ORDER_FIRST, kproc_start, &page_kp) 115 116 #if !defined(NO_SWAPPING) 117 /* the kernel process "vm_daemon"*/ 118 static void vm_daemon __P((void)); 119 static struct proc *vmproc; 120 121 static struct kproc_desc vm_kp = { 122 "vmdaemon", 123 vm_daemon, 124 &vmproc 125 }; 126 SYSINIT(vmdaemon, SI_SUB_KTHREAD_VM, SI_ORDER_FIRST, kproc_start, &vm_kp) 127 #endif 128 129 130 int vm_pages_needed=0; /* Event on which pageout daemon sleeps */ 131 int vm_pageout_deficit=0; /* Estimated number of pages deficit */ 132 int vm_pageout_pages_needed=0; /* flag saying that the pageout daemon needs pages */ 133 134 #if !defined(NO_SWAPPING) 135 static int vm_pageout_req_swapout; /* XXX */ 136 static int vm_daemon_needed; 137 #endif 138 extern int vm_swap_size; 139 static int vm_pageout_stats_max=0, vm_pageout_stats_interval = 0; 140 static int vm_pageout_full_stats_interval = 0; 141 static int vm_pageout_stats_free_max=0, vm_pageout_algorithm_lru=0; 142 static int defer_swap_pageouts=0; 143 static int disable_swap_pageouts=0; 144 145 static int max_page_launder=100; 146 #if defined(NO_SWAPPING) 147 static int vm_swap_enabled=0; 148 static int vm_swap_idle_enabled=0; 149 #else 150 static int vm_swap_enabled=1; 151 static int vm_swap_idle_enabled=0; 152 #endif 153 154 SYSCTL_INT(_vm, VM_PAGEOUT_ALGORITHM, pageout_algorithm, 155 CTLFLAG_RW, &vm_pageout_algorithm_lru, 0, "LRU page mgmt"); 156 157 SYSCTL_INT(_vm, OID_AUTO, pageout_stats_max, 158 CTLFLAG_RW, &vm_pageout_stats_max, 0, "Max pageout stats scan length"); 159 160 SYSCTL_INT(_vm, OID_AUTO, pageout_full_stats_interval, 161 CTLFLAG_RW, &vm_pageout_full_stats_interval, 0, "Interval for full stats scan"); 162 163 SYSCTL_INT(_vm, OID_AUTO, pageout_stats_interval, 164 CTLFLAG_RW, &vm_pageout_stats_interval, 0, "Interval for partial stats scan"); 165 166 SYSCTL_INT(_vm, OID_AUTO, pageout_stats_free_max, 167 CTLFLAG_RW, &vm_pageout_stats_free_max, 0, "Not implemented"); 168 169 #if defined(NO_SWAPPING) 170 SYSCTL_INT(_vm, VM_SWAPPING_ENABLED, swap_enabled, 171 CTLFLAG_RD, &vm_swap_enabled, 0, ""); 172 SYSCTL_INT(_vm, OID_AUTO, swap_idle_enabled, 173 CTLFLAG_RD, &vm_swap_idle_enabled, 0, ""); 174 #else 175 SYSCTL_INT(_vm, VM_SWAPPING_ENABLED, swap_enabled, 176 CTLFLAG_RW, &vm_swap_enabled, 0, "Enable entire process swapout"); 177 SYSCTL_INT(_vm, OID_AUTO, swap_idle_enabled, 178 CTLFLAG_RW, &vm_swap_idle_enabled, 0, "Allow swapout on idle criteria"); 179 #endif 180 181 SYSCTL_INT(_vm, OID_AUTO, defer_swapspace_pageouts, 182 CTLFLAG_RW, &defer_swap_pageouts, 0, "Give preference to dirty pages in mem"); 183 184 SYSCTL_INT(_vm, OID_AUTO, disable_swapspace_pageouts, 185 CTLFLAG_RW, &disable_swap_pageouts, 0, "Disallow swapout of dirty pages"); 186 187 SYSCTL_INT(_vm, OID_AUTO, max_page_launder, 188 CTLFLAG_RW, &max_page_launder, 0, "Maximum number of pages to clean per pass"); 189 190 191 #define VM_PAGEOUT_PAGE_COUNT 16 192 int vm_pageout_page_count = VM_PAGEOUT_PAGE_COUNT; 193 194 int vm_page_max_wired; /* XXX max # of wired pages system-wide */ 195 196 #if !defined(NO_SWAPPING) 197 typedef void freeer_fcn_t __P((vm_map_t, vm_object_t, vm_pindex_t, int)); 198 static void vm_pageout_map_deactivate_pages __P((vm_map_t, vm_pindex_t)); 199 static freeer_fcn_t vm_pageout_object_deactivate_pages; 200 static void vm_req_vmdaemon __P((void)); 201 #endif 202 static void vm_pageout_page_stats(void); 203 204 /* 205 * vm_pageout_clean: 206 * 207 * Clean the page and remove it from the laundry. 208 * 209 * We set the busy bit to cause potential page faults on this page to 210 * block. Note the careful timing, however, the busy bit isn't set till 211 * late and we cannot do anything that will mess with the page. 212 */ 213 214 static int 215 vm_pageout_clean(m) 216 vm_page_t m; 217 { 218 register vm_object_t object; 219 vm_page_t mc[2*vm_pageout_page_count]; 220 int pageout_count; 221 int ib, is, page_base; 222 vm_pindex_t pindex = m->pindex; 223 224 object = m->object; 225 226 /* 227 * It doesn't cost us anything to pageout OBJT_DEFAULT or OBJT_SWAP 228 * with the new swapper, but we could have serious problems paging 229 * out other object types if there is insufficient memory. 230 * 231 * Unfortunately, checking free memory here is far too late, so the 232 * check has been moved up a procedural level. 233 */ 234 235 /* 236 * Don't mess with the page if it's busy. 237 */ 238 if ((m->hold_count != 0) || 239 ((m->busy != 0) || (m->flags & PG_BUSY))) 240 return 0; 241 242 mc[vm_pageout_page_count] = m; 243 pageout_count = 1; 244 page_base = vm_pageout_page_count; 245 ib = 1; 246 is = 1; 247 248 /* 249 * Scan object for clusterable pages. 250 * 251 * We can cluster ONLY if: ->> the page is NOT 252 * clean, wired, busy, held, or mapped into a 253 * buffer, and one of the following: 254 * 1) The page is inactive, or a seldom used 255 * active page. 256 * -or- 257 * 2) we force the issue. 258 * 259 * During heavy mmap/modification loads the pageout 260 * daemon can really fragment the underlying file 261 * due to flushing pages out of order and not trying 262 * align the clusters (which leave sporatic out-of-order 263 * holes). To solve this problem we do the reverse scan 264 * first and attempt to align our cluster, then do a 265 * forward scan if room remains. 266 */ 267 268 more: 269 while (ib && pageout_count < vm_pageout_page_count) { 270 vm_page_t p; 271 272 if (ib > pindex) { 273 ib = 0; 274 break; 275 } 276 277 if ((p = vm_page_lookup(object, pindex - ib)) == NULL) { 278 ib = 0; 279 break; 280 } 281 if (((p->queue - p->pc) == PQ_CACHE) || 282 (p->flags & PG_BUSY) || p->busy) { 283 ib = 0; 284 break; 285 } 286 vm_page_test_dirty(p); 287 if ((p->dirty & p->valid) == 0 || 288 p->queue != PQ_INACTIVE || 289 p->wire_count != 0 || 290 p->hold_count != 0) { 291 ib = 0; 292 break; 293 } 294 mc[--page_base] = p; 295 ++pageout_count; 296 ++ib; 297 /* 298 * alignment boundry, stop here and switch directions. Do 299 * not clear ib. 300 */ 301 if ((pindex - (ib - 1)) % vm_pageout_page_count == 0) 302 break; 303 } 304 305 while (pageout_count < vm_pageout_page_count && 306 pindex + is < object->size) { 307 vm_page_t p; 308 309 if ((p = vm_page_lookup(object, pindex + is)) == NULL) 310 break; 311 if (((p->queue - p->pc) == PQ_CACHE) || 312 (p->flags & PG_BUSY) || p->busy) { 313 break; 314 } 315 vm_page_test_dirty(p); 316 if ((p->dirty & p->valid) == 0 || 317 p->queue != PQ_INACTIVE || 318 p->wire_count != 0 || 319 p->hold_count != 0) { 320 break; 321 } 322 mc[page_base + pageout_count] = p; 323 ++pageout_count; 324 ++is; 325 } 326 327 /* 328 * If we exhausted our forward scan, continue with the reverse scan 329 * when possible, even past a page boundry. This catches boundry 330 * conditions. 331 */ 332 if (ib && pageout_count < vm_pageout_page_count) 333 goto more; 334 335 /* 336 * we allow reads during pageouts... 337 */ 338 return vm_pageout_flush(&mc[page_base], pageout_count, 0); 339 } 340 341 /* 342 * vm_pageout_flush() - launder the given pages 343 * 344 * The given pages are laundered. Note that we setup for the start of 345 * I/O ( i.e. busy the page ), mark it read-only, and bump the object 346 * reference count all in here rather then in the parent. If we want 347 * the parent to do more sophisticated things we may have to change 348 * the ordering. 349 */ 350 351 int 352 vm_pageout_flush(mc, count, flags) 353 vm_page_t *mc; 354 int count; 355 int flags; 356 { 357 register vm_object_t object; 358 int pageout_status[count]; 359 int numpagedout = 0; 360 int i; 361 362 /* 363 * Initiate I/O. Bump the vm_page_t->busy counter and 364 * mark the pages read-only. 365 * 366 * We do not have to fixup the clean/dirty bits here... we can 367 * allow the pager to do it after the I/O completes. 368 */ 369 370 for (i = 0; i < count; i++) { 371 vm_page_io_start(mc[i]); 372 vm_page_protect(mc[i], VM_PROT_READ); 373 } 374 375 object = mc[0]->object; 376 vm_object_pip_add(object, count); 377 378 vm_pager_put_pages(object, mc, count, 379 (flags | ((object == kernel_object) ? OBJPC_SYNC : 0)), 380 pageout_status); 381 382 for (i = 0; i < count; i++) { 383 vm_page_t mt = mc[i]; 384 385 switch (pageout_status[i]) { 386 case VM_PAGER_OK: 387 numpagedout++; 388 break; 389 case VM_PAGER_PEND: 390 numpagedout++; 391 break; 392 case VM_PAGER_BAD: 393 /* 394 * Page outside of range of object. Right now we 395 * essentially lose the changes by pretending it 396 * worked. 397 */ 398 pmap_clear_modify(VM_PAGE_TO_PHYS(mt)); 399 vm_page_undirty(mt); 400 break; 401 case VM_PAGER_ERROR: 402 case VM_PAGER_FAIL: 403 /* 404 * If page couldn't be paged out, then reactivate the 405 * page so it doesn't clog the inactive list. (We 406 * will try paging out it again later). 407 */ 408 vm_page_activate(mt); 409 break; 410 case VM_PAGER_AGAIN: 411 break; 412 } 413 414 /* 415 * If the operation is still going, leave the page busy to 416 * block all other accesses. Also, leave the paging in 417 * progress indicator set so that we don't attempt an object 418 * collapse. 419 */ 420 if (pageout_status[i] != VM_PAGER_PEND) { 421 vm_object_pip_wakeup(object); 422 vm_page_io_finish(mt); 423 } 424 } 425 return numpagedout; 426 } 427 428 #if !defined(NO_SWAPPING) 429 /* 430 * vm_pageout_object_deactivate_pages 431 * 432 * deactivate enough pages to satisfy the inactive target 433 * requirements or if vm_page_proc_limit is set, then 434 * deactivate all of the pages in the object and its 435 * backing_objects. 436 * 437 * The object and map must be locked. 438 */ 439 static void 440 vm_pageout_object_deactivate_pages(map, object, desired, map_remove_only) 441 vm_map_t map; 442 vm_object_t object; 443 vm_pindex_t desired; 444 int map_remove_only; 445 { 446 register vm_page_t p, next; 447 int rcount; 448 int remove_mode; 449 int s; 450 451 if (object->type == OBJT_DEVICE) 452 return; 453 454 while (object) { 455 if (pmap_resident_count(vm_map_pmap(map)) <= desired) 456 return; 457 if (object->paging_in_progress) 458 return; 459 460 remove_mode = map_remove_only; 461 if (object->shadow_count > 1) 462 remove_mode = 1; 463 /* 464 * scan the objects entire memory queue 465 */ 466 rcount = object->resident_page_count; 467 p = TAILQ_FIRST(&object->memq); 468 while (p && (rcount-- > 0)) { 469 int actcount; 470 if (pmap_resident_count(vm_map_pmap(map)) <= desired) 471 return; 472 next = TAILQ_NEXT(p, listq); 473 cnt.v_pdpages++; 474 if (p->wire_count != 0 || 475 p->hold_count != 0 || 476 p->busy != 0 || 477 (p->flags & PG_BUSY) || 478 !pmap_page_exists(vm_map_pmap(map), VM_PAGE_TO_PHYS(p))) { 479 p = next; 480 continue; 481 } 482 483 actcount = pmap_ts_referenced(VM_PAGE_TO_PHYS(p)); 484 if (actcount) { 485 vm_page_flag_set(p, PG_REFERENCED); 486 } else if (p->flags & PG_REFERENCED) { 487 actcount = 1; 488 } 489 490 if ((p->queue != PQ_ACTIVE) && 491 (p->flags & PG_REFERENCED)) { 492 vm_page_activate(p); 493 p->act_count += actcount; 494 vm_page_flag_clear(p, PG_REFERENCED); 495 } else if (p->queue == PQ_ACTIVE) { 496 if ((p->flags & PG_REFERENCED) == 0) { 497 p->act_count -= min(p->act_count, ACT_DECLINE); 498 if (!remove_mode && (vm_pageout_algorithm_lru || (p->act_count == 0))) { 499 vm_page_protect(p, VM_PROT_NONE); 500 vm_page_deactivate(p); 501 } else { 502 s = splvm(); 503 TAILQ_REMOVE(&vm_page_queues[PQ_ACTIVE].pl, p, pageq); 504 TAILQ_INSERT_TAIL(&vm_page_queues[PQ_ACTIVE].pl, p, pageq); 505 splx(s); 506 } 507 } else { 508 vm_page_activate(p); 509 vm_page_flag_clear(p, PG_REFERENCED); 510 if (p->act_count < (ACT_MAX - ACT_ADVANCE)) 511 p->act_count += ACT_ADVANCE; 512 s = splvm(); 513 TAILQ_REMOVE(&vm_page_queues[PQ_ACTIVE].pl, p, pageq); 514 TAILQ_INSERT_TAIL(&vm_page_queues[PQ_ACTIVE].pl, p, pageq); 515 splx(s); 516 } 517 } else if (p->queue == PQ_INACTIVE) { 518 vm_page_protect(p, VM_PROT_NONE); 519 } 520 p = next; 521 } 522 object = object->backing_object; 523 } 524 return; 525 } 526 527 /* 528 * deactivate some number of pages in a map, try to do it fairly, but 529 * that is really hard to do. 530 */ 531 static void 532 vm_pageout_map_deactivate_pages(map, desired) 533 vm_map_t map; 534 vm_pindex_t desired; 535 { 536 vm_map_entry_t tmpe; 537 vm_object_t obj, bigobj; 538 539 if (lockmgr(&map->lock, LK_EXCLUSIVE | LK_NOWAIT, (void *)0, curproc)) { 540 return; 541 } 542 543 bigobj = NULL; 544 545 /* 546 * first, search out the biggest object, and try to free pages from 547 * that. 548 */ 549 tmpe = map->header.next; 550 while (tmpe != &map->header) { 551 if ((tmpe->eflags & MAP_ENTRY_IS_SUB_MAP) == 0) { 552 obj = tmpe->object.vm_object; 553 if ((obj != NULL) && (obj->shadow_count <= 1) && 554 ((bigobj == NULL) || 555 (bigobj->resident_page_count < obj->resident_page_count))) { 556 bigobj = obj; 557 } 558 } 559 tmpe = tmpe->next; 560 } 561 562 if (bigobj) 563 vm_pageout_object_deactivate_pages(map, bigobj, desired, 0); 564 565 /* 566 * Next, hunt around for other pages to deactivate. We actually 567 * do this search sort of wrong -- .text first is not the best idea. 568 */ 569 tmpe = map->header.next; 570 while (tmpe != &map->header) { 571 if (pmap_resident_count(vm_map_pmap(map)) <= desired) 572 break; 573 if ((tmpe->eflags & MAP_ENTRY_IS_SUB_MAP) == 0) { 574 obj = tmpe->object.vm_object; 575 if (obj) 576 vm_pageout_object_deactivate_pages(map, obj, desired, 0); 577 } 578 tmpe = tmpe->next; 579 }; 580 581 /* 582 * Remove all mappings if a process is swapped out, this will free page 583 * table pages. 584 */ 585 if (desired == 0) 586 pmap_remove(vm_map_pmap(map), 587 VM_MIN_ADDRESS, VM_MAXUSER_ADDRESS); 588 vm_map_unlock(map); 589 return; 590 } 591 #endif 592 593 /* 594 * Don't try to be fancy - being fancy can lead to VOP_LOCK's and therefore 595 * to vnode deadlocks. We only do it for OBJT_DEFAULT and OBJT_SWAP objects 596 * which we know can be trivially freed. 597 */ 598 599 void 600 vm_pageout_page_free(vm_page_t m) { 601 vm_object_t object = m->object; 602 int type = object->type; 603 604 if (type == OBJT_SWAP || type == OBJT_DEFAULT) 605 vm_object_reference(object); 606 vm_page_busy(m); 607 vm_page_protect(m, VM_PROT_NONE); 608 vm_page_free(m); 609 if (type == OBJT_SWAP || type == OBJT_DEFAULT) 610 vm_object_deallocate(object); 611 } 612 613 /* 614 * vm_pageout_scan does the dirty work for the pageout daemon. 615 */ 616 static int 617 vm_pageout_scan() 618 { 619 vm_page_t m, next; 620 int page_shortage, maxscan, pcount; 621 int addl_page_shortage, addl_page_shortage_init; 622 int maxlaunder; 623 int launder_loop = 0; 624 struct proc *p, *bigproc; 625 vm_offset_t size, bigsize; 626 vm_object_t object; 627 int force_wakeup = 0; 628 int actcount; 629 int vnodes_skipped = 0; 630 int s; 631 632 /* 633 * Do whatever cleanup that the pmap code can. 634 */ 635 pmap_collect(); 636 637 addl_page_shortage_init = vm_pageout_deficit; 638 vm_pageout_deficit = 0; 639 640 if (max_page_launder == 0) 641 max_page_launder = 1; 642 643 /* 644 * Calculate the number of pages we want to either free or move 645 * to the cache. 646 */ 647 648 page_shortage = vm_paging_target() + addl_page_shortage_init; 649 650 /* 651 * Figure out what to do with dirty pages when they are encountered. 652 * Assume that 1/3 of the pages on the inactive list are clean. If 653 * we think we can reach our target, disable laundering (do not 654 * clean any dirty pages). If we miss the target we will loop back 655 * up and do a laundering run. 656 */ 657 658 if (cnt.v_inactive_count / 3 > page_shortage) { 659 maxlaunder = 0; 660 launder_loop = 0; 661 } else { 662 maxlaunder = 663 (cnt.v_inactive_target > max_page_launder) ? 664 max_page_launder : cnt.v_inactive_target; 665 launder_loop = 1; 666 } 667 668 /* 669 * Start scanning the inactive queue for pages we can move to the 670 * cache or free. The scan will stop when the target is reached or 671 * we have scanned the entire inactive queue. 672 */ 673 674 rescan0: 675 addl_page_shortage = addl_page_shortage_init; 676 maxscan = cnt.v_inactive_count; 677 for (m = TAILQ_FIRST(&vm_page_queues[PQ_INACTIVE].pl); 678 m != NULL && maxscan-- > 0 && page_shortage > 0; 679 m = next) { 680 681 cnt.v_pdpages++; 682 683 if (m->queue != PQ_INACTIVE) { 684 goto rescan0; 685 } 686 687 next = TAILQ_NEXT(m, pageq); 688 689 if (m->hold_count) { 690 s = splvm(); 691 TAILQ_REMOVE(&vm_page_queues[PQ_INACTIVE].pl, m, pageq); 692 TAILQ_INSERT_TAIL(&vm_page_queues[PQ_INACTIVE].pl, m, pageq); 693 splx(s); 694 addl_page_shortage++; 695 continue; 696 } 697 /* 698 * Dont mess with busy pages, keep in the front of the 699 * queue, most likely are being paged out. 700 */ 701 if (m->busy || (m->flags & PG_BUSY)) { 702 addl_page_shortage++; 703 continue; 704 } 705 706 /* 707 * If the object is not being used, we ignore previous 708 * references. 709 */ 710 if (m->object->ref_count == 0) { 711 vm_page_flag_clear(m, PG_REFERENCED); 712 pmap_clear_reference(VM_PAGE_TO_PHYS(m)); 713 714 /* 715 * Otherwise, if the page has been referenced while in the 716 * inactive queue, we bump the "activation count" upwards, 717 * making it less likely that the page will be added back to 718 * the inactive queue prematurely again. Here we check the 719 * page tables (or emulated bits, if any), given the upper 720 * level VM system not knowing anything about existing 721 * references. 722 */ 723 } else if (((m->flags & PG_REFERENCED) == 0) && 724 (actcount = pmap_ts_referenced(VM_PAGE_TO_PHYS(m)))) { 725 vm_page_activate(m); 726 m->act_count += (actcount + ACT_ADVANCE); 727 continue; 728 } 729 730 /* 731 * If the upper level VM system knows about any page 732 * references, we activate the page. We also set the 733 * "activation count" higher than normal so that we will less 734 * likely place pages back onto the inactive queue again. 735 */ 736 if ((m->flags & PG_REFERENCED) != 0) { 737 vm_page_flag_clear(m, PG_REFERENCED); 738 actcount = pmap_ts_referenced(VM_PAGE_TO_PHYS(m)); 739 vm_page_activate(m); 740 m->act_count += (actcount + ACT_ADVANCE + 1); 741 continue; 742 } 743 744 /* 745 * If the upper level VM system doesn't know anything about 746 * the page being dirty, we have to check for it again. As 747 * far as the VM code knows, any partially dirty pages are 748 * fully dirty. 749 */ 750 if (m->dirty == 0) { 751 vm_page_test_dirty(m); 752 } else { 753 vm_page_dirty(m); 754 } 755 756 /* 757 * Invalid pages can be easily freed 758 */ 759 if (m->valid == 0) { 760 vm_pageout_page_free(m); 761 cnt.v_dfree++; 762 --page_shortage; 763 764 /* 765 * Clean pages can be placed onto the cache queue. 766 */ 767 } else if (m->dirty == 0) { 768 vm_page_cache(m); 769 --page_shortage; 770 771 /* 772 * Dirty pages need to be paged out. Note that we clean 773 * only a limited number of pages per pagedaemon pass. 774 */ 775 } else if (maxlaunder > 0) { 776 int written; 777 int swap_pageouts_ok; 778 struct vnode *vp = NULL; 779 780 object = m->object; 781 782 if ((object->type != OBJT_SWAP) && (object->type != OBJT_DEFAULT)) { 783 swap_pageouts_ok = 1; 784 } else { 785 swap_pageouts_ok = !(defer_swap_pageouts || disable_swap_pageouts); 786 swap_pageouts_ok |= (!disable_swap_pageouts && defer_swap_pageouts && 787 vm_page_count_min()); 788 789 } 790 791 /* 792 * We don't bother paging objects that are "dead". 793 * Those objects are in a "rundown" state. 794 */ 795 if (!swap_pageouts_ok || (object->flags & OBJ_DEAD)) { 796 s = splvm(); 797 TAILQ_REMOVE(&vm_page_queues[PQ_INACTIVE].pl, m, pageq); 798 TAILQ_INSERT_TAIL(&vm_page_queues[PQ_INACTIVE].pl, m, pageq); 799 splx(s); 800 continue; 801 } 802 803 /* 804 * For now we protect against potential memory 805 * deadlocks by requiring significant memory to be 806 * free if the object is not OBJT_DEFAULT or OBJT_SWAP. 807 * We do not 'trust' any other object type to operate 808 * with low memory, not even OBJT_DEVICE. The VM 809 * allocator will special case allocations done by 810 * the pageout daemon so the check below actually 811 * does have some hysteresis in it. It isn't the best 812 * solution, though. 813 */ 814 815 if (object->type != OBJT_DEFAULT && 816 object->type != OBJT_SWAP && 817 cnt.v_free_count < cnt.v_free_reserved) { 818 s = splvm(); 819 TAILQ_REMOVE(&vm_page_queues[PQ_INACTIVE].pl, m, pageq); 820 TAILQ_INSERT_TAIL(&vm_page_queues[PQ_INACTIVE].pl, m, 821 pageq); 822 splx(s); 823 continue; 824 } 825 826 /* 827 * Presumably we have sufficient free memory to do 828 * the more sophisticated checks and locking required 829 * for vnodes. 830 * 831 * The object is already known NOT to be dead. The 832 * vget() may still block, though, because 833 * VOP_ISLOCKED() doesn't check to see if an inode 834 * (v_data) is associated with the vnode. If it isn't, 835 * vget() will load in it from disk. Worse, vget() 836 * may actually get stuck waiting on "inode" if another 837 * process is in the process of bringing the inode in. 838 * This is bad news for us either way. 839 * 840 * So for the moment we check v_data == NULL as a 841 * workaround. This means that vnodes which do not 842 * use v_data in the way we expect probably will not 843 * wind up being paged out by the pager and it will be 844 * up to the syncer to get them. That's better then 845 * us blocking here. 846 * 847 * This whole code section is bogus - we need to fix 848 * the vnode pager to handle vm_page_t's without us 849 * having to do any sophisticated VOP tests. 850 */ 851 852 if (object->type == OBJT_VNODE) { 853 vp = object->handle; 854 855 if (VOP_ISLOCKED(vp, NULL) || 856 vp->v_data == NULL || 857 vget(vp, LK_EXCLUSIVE|LK_NOOBJ, curproc)) { 858 if ((m->queue == PQ_INACTIVE) && 859 (m->hold_count == 0) && 860 (m->busy == 0) && 861 (m->flags & PG_BUSY) == 0) { 862 s = splvm(); 863 TAILQ_REMOVE(&vm_page_queues[PQ_INACTIVE].pl, m, pageq); 864 TAILQ_INSERT_TAIL(&vm_page_queues[PQ_INACTIVE].pl, m, pageq); 865 splx(s); 866 } 867 if (object->flags & OBJ_MIGHTBEDIRTY) 868 vnodes_skipped++; 869 continue; 870 } 871 872 /* 873 * The page might have been moved to another queue 874 * during potential blocking in vget() above. 875 */ 876 if (m->queue != PQ_INACTIVE) { 877 if (object->flags & OBJ_MIGHTBEDIRTY) 878 vnodes_skipped++; 879 vput(vp); 880 continue; 881 } 882 883 /* 884 * The page may have been busied during the blocking in 885 * vput(); We don't move the page back onto the end of 886 * the queue so that statistics are more correct if we don't. 887 */ 888 if (m->busy || (m->flags & PG_BUSY)) { 889 vput(vp); 890 continue; 891 } 892 893 /* 894 * If the page has become held, then skip it 895 */ 896 if (m->hold_count) { 897 s = splvm(); 898 TAILQ_REMOVE(&vm_page_queues[PQ_INACTIVE].pl, m, pageq); 899 TAILQ_INSERT_TAIL(&vm_page_queues[PQ_INACTIVE].pl, m, pageq); 900 splx(s); 901 if (object->flags & OBJ_MIGHTBEDIRTY) 902 vnodes_skipped++; 903 vput(vp); 904 continue; 905 } 906 } 907 908 /* 909 * If a page is dirty, then it is either being washed 910 * (but not yet cleaned) or it is still in the 911 * laundry. If it is still in the laundry, then we 912 * start the cleaning operation. 913 */ 914 written = vm_pageout_clean(m); 915 if (vp) 916 vput(vp); 917 918 maxlaunder -= written; 919 } 920 } 921 922 /* 923 * If we still have a page shortage and we didn't launder anything, 924 * run the inactive scan again and launder something this time. 925 */ 926 927 if (launder_loop == 0 && page_shortage > 0) { 928 launder_loop = 1; 929 maxlaunder = 930 (cnt.v_inactive_target > max_page_launder) ? 931 max_page_launder : cnt.v_inactive_target; 932 goto rescan0; 933 } 934 935 /* 936 * Compute the page shortage from the point of view of having to 937 * move pages from the active queue to the inactive queue. 938 */ 939 940 page_shortage = (cnt.v_inactive_target + cnt.v_cache_min) - 941 (cnt.v_free_count + cnt.v_inactive_count + cnt.v_cache_count); 942 page_shortage += addl_page_shortage; 943 944 /* 945 * Scan the active queue for things we can deactivate 946 */ 947 948 pcount = cnt.v_active_count; 949 m = TAILQ_FIRST(&vm_page_queues[PQ_ACTIVE].pl); 950 951 while ((m != NULL) && (pcount-- > 0) && (page_shortage > 0)) { 952 953 /* 954 * This is a consistancy check, and should likely be a panic 955 * or warning. 956 */ 957 if (m->queue != PQ_ACTIVE) { 958 break; 959 } 960 961 next = TAILQ_NEXT(m, pageq); 962 /* 963 * Don't deactivate pages that are busy. 964 */ 965 if ((m->busy != 0) || 966 (m->flags & PG_BUSY) || 967 (m->hold_count != 0)) { 968 s = splvm(); 969 TAILQ_REMOVE(&vm_page_queues[PQ_ACTIVE].pl, m, pageq); 970 TAILQ_INSERT_TAIL(&vm_page_queues[PQ_ACTIVE].pl, m, pageq); 971 splx(s); 972 m = next; 973 continue; 974 } 975 976 /* 977 * The count for pagedaemon pages is done after checking the 978 * page for eligbility... 979 */ 980 cnt.v_pdpages++; 981 982 /* 983 * Check to see "how much" the page has been used. 984 */ 985 actcount = 0; 986 if (m->object->ref_count != 0) { 987 if (m->flags & PG_REFERENCED) { 988 actcount += 1; 989 } 990 actcount += pmap_ts_referenced(VM_PAGE_TO_PHYS(m)); 991 if (actcount) { 992 m->act_count += ACT_ADVANCE + actcount; 993 if (m->act_count > ACT_MAX) 994 m->act_count = ACT_MAX; 995 } 996 } 997 998 /* 999 * Since we have "tested" this bit, we need to clear it now. 1000 */ 1001 vm_page_flag_clear(m, PG_REFERENCED); 1002 1003 /* 1004 * Only if an object is currently being used, do we use the 1005 * page activation count stats. 1006 */ 1007 if (actcount && (m->object->ref_count != 0)) { 1008 s = splvm(); 1009 TAILQ_REMOVE(&vm_page_queues[PQ_ACTIVE].pl, m, pageq); 1010 TAILQ_INSERT_TAIL(&vm_page_queues[PQ_ACTIVE].pl, m, pageq); 1011 splx(s); 1012 } else { 1013 m->act_count -= min(m->act_count, ACT_DECLINE); 1014 if (vm_pageout_algorithm_lru || 1015 (m->object->ref_count == 0) || (m->act_count == 0)) { 1016 page_shortage--; 1017 if (m->object->ref_count == 0) { 1018 vm_page_protect(m, VM_PROT_NONE); 1019 if (m->dirty == 0) 1020 vm_page_cache(m); 1021 else 1022 vm_page_deactivate(m); 1023 } else { 1024 vm_page_deactivate(m); 1025 } 1026 } else { 1027 s = splvm(); 1028 TAILQ_REMOVE(&vm_page_queues[PQ_ACTIVE].pl, m, pageq); 1029 TAILQ_INSERT_TAIL(&vm_page_queues[PQ_ACTIVE].pl, m, pageq); 1030 splx(s); 1031 } 1032 } 1033 m = next; 1034 } 1035 1036 s = splvm(); 1037 1038 /* 1039 * We try to maintain some *really* free pages, this allows interrupt 1040 * code to be guaranteed space. Since both cache and free queues 1041 * are considered basically 'free', moving pages from cache to free 1042 * does not effect other calculations. 1043 */ 1044 1045 while (cnt.v_free_count < cnt.v_free_reserved) { 1046 static int cache_rover = 0; 1047 m = vm_page_list_find(PQ_CACHE, cache_rover, FALSE); 1048 if (!m) 1049 break; 1050 if ((m->flags & PG_BUSY) || m->busy || m->hold_count || m->wire_count) { 1051 #ifdef INVARIANTS 1052 printf("Warning: busy page %p found in cache\n", m); 1053 #endif 1054 vm_page_deactivate(m); 1055 continue; 1056 } 1057 cache_rover = (cache_rover + PQ_PRIME2) & PQ_L2_MASK; 1058 vm_pageout_page_free(m); 1059 cnt.v_dfree++; 1060 } 1061 splx(s); 1062 1063 #if !defined(NO_SWAPPING) 1064 /* 1065 * Idle process swapout -- run once per second. 1066 */ 1067 if (vm_swap_idle_enabled) { 1068 static long lsec; 1069 if (time_second != lsec) { 1070 vm_pageout_req_swapout |= VM_SWAP_IDLE; 1071 vm_req_vmdaemon(); 1072 lsec = time_second; 1073 } 1074 } 1075 #endif 1076 1077 /* 1078 * If we didn't get enough free pages, and we have skipped a vnode 1079 * in a writeable object, wakeup the sync daemon. And kick swapout 1080 * if we did not get enough free pages. 1081 */ 1082 if (vm_paging_target() > 0) { 1083 if (vnodes_skipped && vm_page_count_min()) 1084 (void) speedup_syncer(); 1085 #if !defined(NO_SWAPPING) 1086 if (vm_swap_enabled && vm_page_count_target()) { 1087 vm_req_vmdaemon(); 1088 vm_pageout_req_swapout |= VM_SWAP_NORMAL; 1089 } 1090 #endif 1091 } 1092 1093 /* 1094 * make sure that we have swap space -- if we are low on memory and 1095 * swap -- then kill the biggest process. 1096 */ 1097 if ((vm_swap_size == 0 || swap_pager_full) && vm_page_count_min()) { 1098 bigproc = NULL; 1099 bigsize = 0; 1100 for (p = allproc.lh_first; p != 0; p = p->p_list.le_next) { 1101 /* 1102 * if this is a system process, skip it 1103 */ 1104 if ((p->p_flag & P_SYSTEM) || (p->p_lock > 0) || 1105 (p->p_pid == 1) || 1106 ((p->p_pid < 48) && (vm_swap_size != 0))) { 1107 continue; 1108 } 1109 /* 1110 * if the process is in a non-running type state, 1111 * don't touch it. 1112 */ 1113 if (p->p_stat != SRUN && p->p_stat != SSLEEP) { 1114 continue; 1115 } 1116 /* 1117 * get the process size 1118 */ 1119 size = vmspace_resident_count(p->p_vmspace); 1120 /* 1121 * if the this process is bigger than the biggest one 1122 * remember it. 1123 */ 1124 if (size > bigsize) { 1125 bigproc = p; 1126 bigsize = size; 1127 } 1128 } 1129 if (bigproc != NULL) { 1130 killproc(bigproc, "out of swap space"); 1131 bigproc->p_estcpu = 0; 1132 bigproc->p_nice = PRIO_MIN; 1133 resetpriority(bigproc); 1134 wakeup(&cnt.v_free_count); 1135 } 1136 } 1137 return force_wakeup; 1138 } 1139 1140 /* 1141 * This routine tries to maintain the pseudo LRU active queue, 1142 * so that during long periods of time where there is no paging, 1143 * that some statistic accumlation still occurs. This code 1144 * helps the situation where paging just starts to occur. 1145 */ 1146 static void 1147 vm_pageout_page_stats() 1148 { 1149 int s; 1150 vm_page_t m,next; 1151 int pcount,tpcount; /* Number of pages to check */ 1152 static int fullintervalcount = 0; 1153 int page_shortage; 1154 1155 page_shortage = 1156 (cnt.v_inactive_target + cnt.v_cache_max + cnt.v_free_min) - 1157 (cnt.v_free_count + cnt.v_inactive_count + cnt.v_cache_count); 1158 1159 if (page_shortage <= 0) 1160 return; 1161 1162 pcount = cnt.v_active_count; 1163 fullintervalcount += vm_pageout_stats_interval; 1164 if (fullintervalcount < vm_pageout_full_stats_interval) { 1165 tpcount = (vm_pageout_stats_max * cnt.v_active_count) / cnt.v_page_count; 1166 if (pcount > tpcount) 1167 pcount = tpcount; 1168 } 1169 1170 m = TAILQ_FIRST(&vm_page_queues[PQ_ACTIVE].pl); 1171 while ((m != NULL) && (pcount-- > 0)) { 1172 int actcount; 1173 1174 if (m->queue != PQ_ACTIVE) { 1175 break; 1176 } 1177 1178 next = TAILQ_NEXT(m, pageq); 1179 /* 1180 * Don't deactivate pages that are busy. 1181 */ 1182 if ((m->busy != 0) || 1183 (m->flags & PG_BUSY) || 1184 (m->hold_count != 0)) { 1185 s = splvm(); 1186 TAILQ_REMOVE(&vm_page_queues[PQ_ACTIVE].pl, m, pageq); 1187 TAILQ_INSERT_TAIL(&vm_page_queues[PQ_ACTIVE].pl, m, pageq); 1188 splx(s); 1189 m = next; 1190 continue; 1191 } 1192 1193 actcount = 0; 1194 if (m->flags & PG_REFERENCED) { 1195 vm_page_flag_clear(m, PG_REFERENCED); 1196 actcount += 1; 1197 } 1198 1199 actcount += pmap_ts_referenced(VM_PAGE_TO_PHYS(m)); 1200 if (actcount) { 1201 m->act_count += ACT_ADVANCE + actcount; 1202 if (m->act_count > ACT_MAX) 1203 m->act_count = ACT_MAX; 1204 s = splvm(); 1205 TAILQ_REMOVE(&vm_page_queues[PQ_ACTIVE].pl, m, pageq); 1206 TAILQ_INSERT_TAIL(&vm_page_queues[PQ_ACTIVE].pl, m, pageq); 1207 splx(s); 1208 } else { 1209 if (m->act_count == 0) { 1210 /* 1211 * We turn off page access, so that we have more accurate 1212 * RSS stats. We don't do this in the normal page deactivation 1213 * when the system is loaded VM wise, because the cost of 1214 * the large number of page protect operations would be higher 1215 * than the value of doing the operation. 1216 */ 1217 vm_page_protect(m, VM_PROT_NONE); 1218 vm_page_deactivate(m); 1219 } else { 1220 m->act_count -= min(m->act_count, ACT_DECLINE); 1221 s = splvm(); 1222 TAILQ_REMOVE(&vm_page_queues[PQ_ACTIVE].pl, m, pageq); 1223 TAILQ_INSERT_TAIL(&vm_page_queues[PQ_ACTIVE].pl, m, pageq); 1224 splx(s); 1225 } 1226 } 1227 1228 m = next; 1229 } 1230 } 1231 1232 static int 1233 vm_pageout_free_page_calc(count) 1234 vm_size_t count; 1235 { 1236 if (count < cnt.v_page_count) 1237 return 0; 1238 /* 1239 * free_reserved needs to include enough for the largest swap pager 1240 * structures plus enough for any pv_entry structs when paging. 1241 */ 1242 if (cnt.v_page_count > 1024) 1243 cnt.v_free_min = 4 + (cnt.v_page_count - 1024) / 200; 1244 else 1245 cnt.v_free_min = 4; 1246 cnt.v_pageout_free_min = (2*MAXBSIZE)/PAGE_SIZE + 1247 cnt.v_interrupt_free_min; 1248 cnt.v_free_reserved = vm_pageout_page_count + 1249 cnt.v_pageout_free_min + (count / 768) + PQ_L2_SIZE; 1250 cnt.v_free_severe = cnt.v_free_min / 2; 1251 cnt.v_free_min += cnt.v_free_reserved; 1252 cnt.v_free_severe += cnt.v_free_reserved; 1253 return 1; 1254 } 1255 1256 1257 /* 1258 * vm_pageout is the high level pageout daemon. 1259 */ 1260 static void 1261 vm_pageout() 1262 { 1263 /* 1264 * Initialize some paging parameters. 1265 */ 1266 1267 cnt.v_interrupt_free_min = 2; 1268 if (cnt.v_page_count < 2000) 1269 vm_pageout_page_count = 8; 1270 1271 vm_pageout_free_page_calc(cnt.v_page_count); 1272 /* 1273 * free_reserved needs to include enough for the largest swap pager 1274 * structures plus enough for any pv_entry structs when paging. 1275 */ 1276 if (cnt.v_free_count > 6144) 1277 cnt.v_free_target = 3 * cnt.v_free_min + cnt.v_free_reserved; 1278 else 1279 cnt.v_free_target = 2 * cnt.v_free_min + cnt.v_free_reserved; 1280 1281 if (cnt.v_free_count > 2048) { 1282 cnt.v_cache_min = cnt.v_free_target; 1283 cnt.v_cache_max = 2 * cnt.v_cache_min; 1284 cnt.v_inactive_target = (3 * cnt.v_free_target) / 2; 1285 } else { 1286 cnt.v_cache_min = 0; 1287 cnt.v_cache_max = 0; 1288 cnt.v_inactive_target = cnt.v_free_count / 4; 1289 } 1290 if (cnt.v_inactive_target > cnt.v_free_count / 3) 1291 cnt.v_inactive_target = cnt.v_free_count / 3; 1292 1293 /* XXX does not really belong here */ 1294 if (vm_page_max_wired == 0) 1295 vm_page_max_wired = cnt.v_free_count / 3; 1296 1297 if (vm_pageout_stats_max == 0) 1298 vm_pageout_stats_max = cnt.v_free_target; 1299 1300 /* 1301 * Set interval in seconds for stats scan. 1302 */ 1303 if (vm_pageout_stats_interval == 0) 1304 vm_pageout_stats_interval = 5; 1305 if (vm_pageout_full_stats_interval == 0) 1306 vm_pageout_full_stats_interval = vm_pageout_stats_interval * 4; 1307 1308 1309 /* 1310 * Set maximum free per pass 1311 */ 1312 if (vm_pageout_stats_free_max == 0) 1313 vm_pageout_stats_free_max = 5; 1314 1315 max_page_launder = (cnt.v_page_count > 1800 ? 32 : 16); 1316 1317 curproc->p_flag |= P_BUFEXHAUST; 1318 swap_pager_swap_init(); 1319 /* 1320 * The pageout daemon is never done, so loop forever. 1321 */ 1322 while (TRUE) { 1323 int error; 1324 int s = splvm(); 1325 1326 if (vm_pages_needed && vm_page_count_min()) { 1327 /* 1328 * Still not done, sleep a bit and go again 1329 */ 1330 vm_pages_needed = 0; 1331 tsleep(&vm_pages_needed, PVM, "psleep", hz/2); 1332 } else { 1333 /* 1334 * Good enough, sleep & handle stats 1335 */ 1336 vm_pages_needed = 0; 1337 error = tsleep(&vm_pages_needed, 1338 PVM, "psleep", vm_pageout_stats_interval * hz); 1339 if (error && !vm_pages_needed) { 1340 splx(s); 1341 vm_pageout_page_stats(); 1342 continue; 1343 } 1344 } 1345 1346 if (vm_pages_needed) 1347 cnt.v_pdwakeups++; 1348 vm_pages_needed = 0; 1349 splx(s); 1350 vm_pageout_scan(); 1351 vm_pageout_deficit = 0; 1352 wakeup(&cnt.v_free_count); 1353 } 1354 } 1355 1356 void 1357 pagedaemon_wakeup() 1358 { 1359 if (!vm_pages_needed && curproc != pageproc) { 1360 vm_pages_needed++; 1361 wakeup(&vm_pages_needed); 1362 } 1363 } 1364 1365 #if !defined(NO_SWAPPING) 1366 static void 1367 vm_req_vmdaemon() 1368 { 1369 static int lastrun = 0; 1370 1371 if ((ticks > (lastrun + hz)) || (ticks < lastrun)) { 1372 wakeup(&vm_daemon_needed); 1373 lastrun = ticks; 1374 } 1375 } 1376 1377 static void 1378 vm_daemon() 1379 { 1380 struct proc *p; 1381 1382 while (TRUE) { 1383 tsleep(&vm_daemon_needed, PPAUSE, "psleep", 0); 1384 if (vm_pageout_req_swapout) { 1385 swapout_procs(vm_pageout_req_swapout); 1386 vm_pageout_req_swapout = 0; 1387 } 1388 /* 1389 * scan the processes for exceeding their rlimits or if 1390 * process is swapped out -- deactivate pages 1391 */ 1392 1393 for (p = allproc.lh_first; p != 0; p = p->p_list.le_next) { 1394 vm_pindex_t limit, size; 1395 1396 /* 1397 * if this is a system process or if we have already 1398 * looked at this process, skip it. 1399 */ 1400 if (p->p_flag & (P_SYSTEM | P_WEXIT)) { 1401 continue; 1402 } 1403 /* 1404 * if the process is in a non-running type state, 1405 * don't touch it. 1406 */ 1407 if (p->p_stat != SRUN && p->p_stat != SSLEEP) { 1408 continue; 1409 } 1410 /* 1411 * get a limit 1412 */ 1413 limit = OFF_TO_IDX( 1414 qmin(p->p_rlimit[RLIMIT_RSS].rlim_cur, 1415 p->p_rlimit[RLIMIT_RSS].rlim_max)); 1416 1417 /* 1418 * let processes that are swapped out really be 1419 * swapped out set the limit to nothing (will force a 1420 * swap-out.) 1421 */ 1422 if ((p->p_flag & P_INMEM) == 0) 1423 limit = 0; /* XXX */ 1424 1425 size = vmspace_resident_count(p->p_vmspace); 1426 if (limit >= 0 && size >= limit) { 1427 vm_pageout_map_deactivate_pages( 1428 &p->p_vmspace->vm_map, limit); 1429 } 1430 } 1431 } 1432 } 1433 #endif 1434