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/ktr.h> 82 #include <sys/resourcevar.h> 83 #include <sys/signalvar.h> 84 #include <sys/vnode.h> 85 #include <sys/vmmeter.h> 86 #include <sys/sysctl.h> 87 88 #include <vm/vm.h> 89 #include <vm/vm_param.h> 90 #include <sys/lock.h> 91 #include <vm/vm_object.h> 92 #include <vm/vm_page.h> 93 #include <vm/vm_map.h> 94 #include <vm/vm_pageout.h> 95 #include <vm/vm_pager.h> 96 #include <vm/swap_pager.h> 97 #include <vm/vm_extern.h> 98 99 #include <machine/mutex.h> 100 101 /* 102 * System initialization 103 */ 104 105 /* the kernel process "vm_pageout"*/ 106 static void vm_pageout __P((void)); 107 static int vm_pageout_clean __P((vm_page_t)); 108 static int vm_pageout_scan __P((void)); 109 static int vm_pageout_free_page_calc __P((vm_size_t count)); 110 struct proc *pageproc; 111 112 static struct kproc_desc page_kp = { 113 "pagedaemon", 114 vm_pageout, 115 &pageproc 116 }; 117 SYSINIT(pagedaemon, SI_SUB_KTHREAD_PAGE, SI_ORDER_FIRST, kproc_start, &page_kp) 118 119 #if !defined(NO_SWAPPING) 120 /* the kernel process "vm_daemon"*/ 121 static void vm_daemon __P((void)); 122 static struct proc *vmproc; 123 124 static struct kproc_desc vm_kp = { 125 "vmdaemon", 126 vm_daemon, 127 &vmproc 128 }; 129 SYSINIT(vmdaemon, SI_SUB_KTHREAD_VM, SI_ORDER_FIRST, kproc_start, &vm_kp) 130 #endif 131 132 133 int vm_pages_needed=0; /* Event on which pageout daemon sleeps */ 134 int vm_pageout_deficit=0; /* Estimated number of pages deficit */ 135 int vm_pageout_pages_needed=0; /* flag saying that the pageout daemon needs pages */ 136 137 #if !defined(NO_SWAPPING) 138 static int vm_pageout_req_swapout; /* XXX */ 139 static int vm_daemon_needed; 140 #endif 141 extern int vm_swap_size; 142 static int vm_pageout_stats_max=0, vm_pageout_stats_interval = 0; 143 static int vm_pageout_full_stats_interval = 0; 144 static int vm_pageout_stats_free_max=0, vm_pageout_algorithm_lru=0; 145 static int defer_swap_pageouts=0; 146 static int disable_swap_pageouts=0; 147 148 static int max_page_launder=100; 149 static int vm_pageout_actcmp=0; 150 #if defined(NO_SWAPPING) 151 static int vm_swap_enabled=0; 152 static int vm_swap_idle_enabled=0; 153 #else 154 static int vm_swap_enabled=1; 155 static int vm_swap_idle_enabled=0; 156 #endif 157 158 SYSCTL_INT(_vm, VM_PAGEOUT_ALGORITHM, pageout_algorithm, 159 CTLFLAG_RW, &vm_pageout_algorithm_lru, 0, "LRU page mgmt"); 160 161 SYSCTL_INT(_vm, OID_AUTO, pageout_stats_max, 162 CTLFLAG_RW, &vm_pageout_stats_max, 0, "Max pageout stats scan length"); 163 164 SYSCTL_INT(_vm, OID_AUTO, pageout_full_stats_interval, 165 CTLFLAG_RW, &vm_pageout_full_stats_interval, 0, "Interval for full stats scan"); 166 167 SYSCTL_INT(_vm, OID_AUTO, pageout_stats_interval, 168 CTLFLAG_RW, &vm_pageout_stats_interval, 0, "Interval for partial stats scan"); 169 170 SYSCTL_INT(_vm, OID_AUTO, pageout_stats_free_max, 171 CTLFLAG_RW, &vm_pageout_stats_free_max, 0, "Not implemented"); 172 173 #if defined(NO_SWAPPING) 174 SYSCTL_INT(_vm, VM_SWAPPING_ENABLED, swap_enabled, 175 CTLFLAG_RD, &vm_swap_enabled, 0, ""); 176 SYSCTL_INT(_vm, OID_AUTO, swap_idle_enabled, 177 CTLFLAG_RD, &vm_swap_idle_enabled, 0, ""); 178 #else 179 SYSCTL_INT(_vm, VM_SWAPPING_ENABLED, swap_enabled, 180 CTLFLAG_RW, &vm_swap_enabled, 0, "Enable entire process swapout"); 181 SYSCTL_INT(_vm, OID_AUTO, swap_idle_enabled, 182 CTLFLAG_RW, &vm_swap_idle_enabled, 0, "Allow swapout on idle criteria"); 183 #endif 184 185 SYSCTL_INT(_vm, OID_AUTO, defer_swapspace_pageouts, 186 CTLFLAG_RW, &defer_swap_pageouts, 0, "Give preference to dirty pages in mem"); 187 188 SYSCTL_INT(_vm, OID_AUTO, disable_swapspace_pageouts, 189 CTLFLAG_RW, &disable_swap_pageouts, 0, "Disallow swapout of dirty pages"); 190 191 SYSCTL_INT(_vm, OID_AUTO, max_page_launder, 192 CTLFLAG_RW, &max_page_launder, 0, "Maximum number of pages to clean per pass"); 193 SYSCTL_INT(_vm, OID_AUTO, vm_pageout_actcmp, 194 CTLFLAG_RD, &vm_pageout_actcmp, 0, "pagedaemon agressiveness"); 195 196 197 #define VM_PAGEOUT_PAGE_COUNT 16 198 int vm_pageout_page_count = VM_PAGEOUT_PAGE_COUNT; 199 200 int vm_page_max_wired; /* XXX max # of wired pages system-wide */ 201 202 #if !defined(NO_SWAPPING) 203 typedef void freeer_fcn_t __P((vm_map_t, vm_object_t, vm_pindex_t, int)); 204 static void vm_pageout_map_deactivate_pages __P((vm_map_t, vm_pindex_t)); 205 static freeer_fcn_t vm_pageout_object_deactivate_pages; 206 static void vm_req_vmdaemon __P((void)); 207 #endif 208 static void vm_pageout_page_stats(void); 209 210 /* 211 * vm_pageout_clean: 212 * 213 * Clean the page and remove it from the laundry. 214 * 215 * We set the busy bit to cause potential page faults on this page to 216 * block. Note the careful timing, however, the busy bit isn't set till 217 * late and we cannot do anything that will mess with the page. 218 */ 219 220 static int 221 vm_pageout_clean(m) 222 vm_page_t m; 223 { 224 register vm_object_t object; 225 vm_page_t mc[2*vm_pageout_page_count]; 226 int pageout_count; 227 int ib, is, page_base; 228 vm_pindex_t pindex = m->pindex; 229 230 object = m->object; 231 232 /* 233 * It doesn't cost us anything to pageout OBJT_DEFAULT or OBJT_SWAP 234 * with the new swapper, but we could have serious problems paging 235 * out other object types if there is insufficient memory. 236 * 237 * Unfortunately, checking free memory here is far too late, so the 238 * check has been moved up a procedural level. 239 */ 240 241 /* 242 * Don't mess with the page if it's busy, held, or special 243 */ 244 if ((m->hold_count != 0) || 245 ((m->busy != 0) || (m->flags & (PG_BUSY|PG_UNMANAGED)))) { 246 return 0; 247 } 248 249 mc[vm_pageout_page_count] = m; 250 pageout_count = 1; 251 page_base = vm_pageout_page_count; 252 ib = 1; 253 is = 1; 254 255 /* 256 * Scan object for clusterable pages. 257 * 258 * We can cluster ONLY if: ->> the page is NOT 259 * clean, wired, busy, held, or mapped into a 260 * buffer, and one of the following: 261 * 1) The page is inactive, or a seldom used 262 * active page. 263 * -or- 264 * 2) we force the issue. 265 * 266 * During heavy mmap/modification loads the pageout 267 * daemon can really fragment the underlying file 268 * due to flushing pages out of order and not trying 269 * align the clusters (which leave sporatic out-of-order 270 * holes). To solve this problem we do the reverse scan 271 * first and attempt to align our cluster, then do a 272 * forward scan if room remains. 273 */ 274 275 more: 276 while (ib && pageout_count < vm_pageout_page_count) { 277 vm_page_t p; 278 279 if (ib > pindex) { 280 ib = 0; 281 break; 282 } 283 284 if ((p = vm_page_lookup(object, pindex - ib)) == NULL) { 285 ib = 0; 286 break; 287 } 288 if (((p->queue - p->pc) == PQ_CACHE) || 289 (p->flags & (PG_BUSY|PG_UNMANAGED)) || p->busy) { 290 ib = 0; 291 break; 292 } 293 vm_page_test_dirty(p); 294 if ((p->dirty & p->valid) == 0 || 295 p->queue != PQ_INACTIVE || 296 p->wire_count != 0 || 297 p->hold_count != 0) { 298 ib = 0; 299 break; 300 } 301 mc[--page_base] = p; 302 ++pageout_count; 303 ++ib; 304 /* 305 * alignment boundry, stop here and switch directions. Do 306 * not clear ib. 307 */ 308 if ((pindex - (ib - 1)) % vm_pageout_page_count == 0) 309 break; 310 } 311 312 while (pageout_count < vm_pageout_page_count && 313 pindex + is < object->size) { 314 vm_page_t p; 315 316 if ((p = vm_page_lookup(object, pindex + is)) == NULL) 317 break; 318 if (((p->queue - p->pc) == PQ_CACHE) || 319 (p->flags & (PG_BUSY|PG_UNMANAGED)) || p->busy) { 320 break; 321 } 322 vm_page_test_dirty(p); 323 if ((p->dirty & p->valid) == 0 || 324 p->queue != PQ_INACTIVE || 325 p->wire_count != 0 || 326 p->hold_count != 0) { 327 break; 328 } 329 mc[page_base + pageout_count] = p; 330 ++pageout_count; 331 ++is; 332 } 333 334 /* 335 * If we exhausted our forward scan, continue with the reverse scan 336 * when possible, even past a page boundry. This catches boundry 337 * conditions. 338 */ 339 if (ib && pageout_count < vm_pageout_page_count) 340 goto more; 341 342 /* 343 * we allow reads during pageouts... 344 */ 345 return vm_pageout_flush(&mc[page_base], pageout_count, 0); 346 } 347 348 /* 349 * vm_pageout_flush() - launder the given pages 350 * 351 * The given pages are laundered. Note that we setup for the start of 352 * I/O ( i.e. busy the page ), mark it read-only, and bump the object 353 * reference count all in here rather then in the parent. If we want 354 * the parent to do more sophisticated things we may have to change 355 * the ordering. 356 */ 357 358 int 359 vm_pageout_flush(mc, count, flags) 360 vm_page_t *mc; 361 int count; 362 int flags; 363 { 364 register vm_object_t object; 365 int pageout_status[count]; 366 int numpagedout = 0; 367 int i; 368 369 /* 370 * Initiate I/O. Bump the vm_page_t->busy counter and 371 * mark the pages read-only. 372 * 373 * We do not have to fixup the clean/dirty bits here... we can 374 * allow the pager to do it after the I/O completes. 375 */ 376 377 for (i = 0; i < count; i++) { 378 KASSERT(mc[i]->valid == VM_PAGE_BITS_ALL && mc[i]->dirty == VM_PAGE_BITS_ALL, ("vm_pageout_flush page %p index %d/%d: partially dirty page", mc[i], i, count)); 379 vm_page_io_start(mc[i]); 380 vm_page_protect(mc[i], VM_PROT_READ); 381 } 382 383 object = mc[0]->object; 384 vm_object_pip_add(object, count); 385 386 vm_pager_put_pages(object, mc, count, 387 (flags | ((object == kernel_object) ? OBJPC_SYNC : 0)), 388 pageout_status); 389 390 for (i = 0; i < count; i++) { 391 vm_page_t mt = mc[i]; 392 393 switch (pageout_status[i]) { 394 case VM_PAGER_OK: 395 numpagedout++; 396 break; 397 case VM_PAGER_PEND: 398 numpagedout++; 399 break; 400 case VM_PAGER_BAD: 401 /* 402 * Page outside of range of object. Right now we 403 * essentially lose the changes by pretending it 404 * worked. 405 */ 406 pmap_clear_modify(mt); 407 vm_page_undirty(mt); 408 break; 409 case VM_PAGER_ERROR: 410 case VM_PAGER_FAIL: 411 /* 412 * If page couldn't be paged out, then reactivate the 413 * page so it doesn't clog the inactive list. (We 414 * will try paging out it again later). 415 */ 416 vm_page_activate(mt); 417 break; 418 case VM_PAGER_AGAIN: 419 break; 420 } 421 422 /* 423 * If the operation is still going, leave the page busy to 424 * block all other accesses. Also, leave the paging in 425 * progress indicator set so that we don't attempt an object 426 * collapse. 427 */ 428 if (pageout_status[i] != VM_PAGER_PEND) { 429 vm_object_pip_wakeup(object); 430 vm_page_io_finish(mt); 431 if (!vm_page_count_severe() || !vm_page_try_to_cache(mt)) 432 vm_page_protect(mt, VM_PROT_READ); 433 } 434 } 435 return numpagedout; 436 } 437 438 #if !defined(NO_SWAPPING) 439 /* 440 * vm_pageout_object_deactivate_pages 441 * 442 * deactivate enough pages to satisfy the inactive target 443 * requirements or if vm_page_proc_limit is set, then 444 * deactivate all of the pages in the object and its 445 * backing_objects. 446 * 447 * The object and map must be locked. 448 */ 449 static void 450 vm_pageout_object_deactivate_pages(map, object, desired, map_remove_only) 451 vm_map_t map; 452 vm_object_t object; 453 vm_pindex_t desired; 454 int map_remove_only; 455 { 456 register vm_page_t p, next; 457 int rcount; 458 int remove_mode; 459 int s; 460 461 if (object->type == OBJT_DEVICE || object->type == OBJT_PHYS) 462 return; 463 464 while (object) { 465 if (pmap_resident_count(vm_map_pmap(map)) <= desired) 466 return; 467 if (object->paging_in_progress) 468 return; 469 470 remove_mode = map_remove_only; 471 if (object->shadow_count > 1) 472 remove_mode = 1; 473 /* 474 * scan the objects entire memory queue 475 */ 476 rcount = object->resident_page_count; 477 p = TAILQ_FIRST(&object->memq); 478 while (p && (rcount-- > 0)) { 479 int actcount; 480 if (pmap_resident_count(vm_map_pmap(map)) <= desired) 481 return; 482 next = TAILQ_NEXT(p, listq); 483 cnt.v_pdpages++; 484 if (p->wire_count != 0 || 485 p->hold_count != 0 || 486 p->busy != 0 || 487 (p->flags & (PG_BUSY|PG_UNMANAGED)) || 488 !pmap_page_exists(vm_map_pmap(map), p)) { 489 p = next; 490 continue; 491 } 492 493 actcount = pmap_ts_referenced(p); 494 if (actcount) { 495 vm_page_flag_set(p, PG_REFERENCED); 496 } else if (p->flags & PG_REFERENCED) { 497 actcount = 1; 498 } 499 500 if ((p->queue != PQ_ACTIVE) && 501 (p->flags & PG_REFERENCED)) { 502 vm_page_activate(p); 503 p->act_count += actcount; 504 vm_page_flag_clear(p, PG_REFERENCED); 505 } else if (p->queue == PQ_ACTIVE) { 506 if ((p->flags & PG_REFERENCED) == 0) { 507 p->act_count -= min(p->act_count, ACT_DECLINE); 508 if (!remove_mode && (vm_pageout_algorithm_lru || (p->act_count == 0))) { 509 vm_page_protect(p, VM_PROT_NONE); 510 vm_page_deactivate(p); 511 } else { 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 { 518 vm_page_activate(p); 519 vm_page_flag_clear(p, PG_REFERENCED); 520 if (p->act_count < (ACT_MAX - ACT_ADVANCE)) 521 p->act_count += ACT_ADVANCE; 522 s = splvm(); 523 TAILQ_REMOVE(&vm_page_queues[PQ_ACTIVE].pl, p, pageq); 524 TAILQ_INSERT_TAIL(&vm_page_queues[PQ_ACTIVE].pl, p, pageq); 525 splx(s); 526 } 527 } else if (p->queue == PQ_INACTIVE) { 528 vm_page_protect(p, VM_PROT_NONE); 529 } 530 p = next; 531 } 532 object = object->backing_object; 533 } 534 return; 535 } 536 537 /* 538 * deactivate some number of pages in a map, try to do it fairly, but 539 * that is really hard to do. 540 */ 541 static void 542 vm_pageout_map_deactivate_pages(map, desired) 543 vm_map_t map; 544 vm_pindex_t desired; 545 { 546 vm_map_entry_t tmpe; 547 vm_object_t obj, bigobj; 548 549 if (lockmgr(&map->lock, LK_EXCLUSIVE | LK_NOWAIT, (void *)0, curproc)) { 550 return; 551 } 552 553 bigobj = NULL; 554 555 /* 556 * first, search out the biggest object, and try to free pages from 557 * that. 558 */ 559 tmpe = map->header.next; 560 while (tmpe != &map->header) { 561 if ((tmpe->eflags & MAP_ENTRY_IS_SUB_MAP) == 0) { 562 obj = tmpe->object.vm_object; 563 if ((obj != NULL) && (obj->shadow_count <= 1) && 564 ((bigobj == NULL) || 565 (bigobj->resident_page_count < obj->resident_page_count))) { 566 bigobj = obj; 567 } 568 } 569 tmpe = tmpe->next; 570 } 571 572 if (bigobj) 573 vm_pageout_object_deactivate_pages(map, bigobj, desired, 0); 574 575 /* 576 * Next, hunt around for other pages to deactivate. We actually 577 * do this search sort of wrong -- .text first is not the best idea. 578 */ 579 tmpe = map->header.next; 580 while (tmpe != &map->header) { 581 if (pmap_resident_count(vm_map_pmap(map)) <= desired) 582 break; 583 if ((tmpe->eflags & MAP_ENTRY_IS_SUB_MAP) == 0) { 584 obj = tmpe->object.vm_object; 585 if (obj) 586 vm_pageout_object_deactivate_pages(map, obj, desired, 0); 587 } 588 tmpe = tmpe->next; 589 }; 590 591 /* 592 * Remove all mappings if a process is swapped out, this will free page 593 * table pages. 594 */ 595 if (desired == 0) 596 pmap_remove(vm_map_pmap(map), 597 VM_MIN_ADDRESS, VM_MAXUSER_ADDRESS); 598 vm_map_unlock(map); 599 return; 600 } 601 #endif 602 603 /* 604 * Don't try to be fancy - being fancy can lead to VOP_LOCK's and therefore 605 * to vnode deadlocks. We only do it for OBJT_DEFAULT and OBJT_SWAP objects 606 * which we know can be trivially freed. 607 */ 608 609 void 610 vm_pageout_page_free(vm_page_t m) { 611 vm_object_t object = m->object; 612 int type = object->type; 613 614 if (type == OBJT_SWAP || type == OBJT_DEFAULT) 615 vm_object_reference(object); 616 vm_page_busy(m); 617 vm_page_protect(m, VM_PROT_NONE); 618 vm_page_free(m); 619 if (type == OBJT_SWAP || type == OBJT_DEFAULT) 620 vm_object_deallocate(object); 621 } 622 623 /* 624 * vm_pageout_scan does the dirty work for the pageout daemon. 625 */ 626 static int 627 vm_pageout_scan() 628 { 629 vm_page_t m, next; 630 struct vm_page marker; 631 int page_shortage, maxscan, pcount; 632 int addl_page_shortage, addl_page_shortage_init; 633 int maxlaunder; 634 struct proc *p, *bigproc; 635 vm_offset_t size, bigsize; 636 vm_object_t object; 637 int force_wakeup = 0; 638 int actcount; 639 int vnodes_skipped = 0; 640 int s; 641 642 /* 643 * Do whatever cleanup that the pmap code can. 644 */ 645 pmap_collect(); 646 647 addl_page_shortage_init = vm_pageout_deficit; 648 vm_pageout_deficit = 0; 649 650 if (max_page_launder == 0) 651 max_page_launder = 1; 652 653 /* 654 * Calculate the number of pages we want to either free or move 655 * to the cache. Be more agressive if we aren't making our target. 656 */ 657 658 page_shortage = vm_paging_target() + 659 addl_page_shortage_init + vm_pageout_actcmp; 660 661 /* 662 * Figure out how agressively we should flush dirty pages. 663 */ 664 { 665 int factor = vm_pageout_actcmp; 666 667 maxlaunder = cnt.v_inactive_target / 3 + factor; 668 if (maxlaunder > max_page_launder + factor) 669 maxlaunder = max_page_launder + factor; 670 } 671 672 /* 673 * Initialize our marker 674 */ 675 bzero(&marker, sizeof(marker)); 676 marker.flags = PG_BUSY | PG_FICTITIOUS | PG_MARKER; 677 marker.queue = PQ_INACTIVE; 678 marker.wire_count = 1; 679 680 /* 681 * Start scanning the inactive queue for pages we can move to the 682 * cache or free. The scan will stop when the target is reached or 683 * we have scanned the entire inactive queue. Note that m->act_count 684 * is not used to form decisions for the inactive queue, only for the 685 * active queue. 686 */ 687 688 rescan0: 689 addl_page_shortage = addl_page_shortage_init; 690 maxscan = cnt.v_inactive_count; 691 for (m = TAILQ_FIRST(&vm_page_queues[PQ_INACTIVE].pl); 692 m != NULL && maxscan-- > 0 && page_shortage > 0; 693 m = next) { 694 695 cnt.v_pdpages++; 696 697 if (m->queue != PQ_INACTIVE) { 698 goto rescan0; 699 } 700 701 next = TAILQ_NEXT(m, pageq); 702 703 /* 704 * skip marker pages 705 */ 706 if (m->flags & PG_MARKER) 707 continue; 708 709 if (m->hold_count) { 710 s = splvm(); 711 TAILQ_REMOVE(&vm_page_queues[PQ_INACTIVE].pl, m, pageq); 712 TAILQ_INSERT_TAIL(&vm_page_queues[PQ_INACTIVE].pl, m, pageq); 713 splx(s); 714 addl_page_shortage++; 715 continue; 716 } 717 /* 718 * Dont mess with busy pages, keep in the front of the 719 * queue, most likely are being paged out. 720 */ 721 if (m->busy || (m->flags & PG_BUSY)) { 722 addl_page_shortage++; 723 continue; 724 } 725 726 /* 727 * If the object is not being used, we ignore previous 728 * references. 729 */ 730 if (m->object->ref_count == 0) { 731 vm_page_flag_clear(m, PG_REFERENCED); 732 pmap_clear_reference(m); 733 734 /* 735 * Otherwise, if the page has been referenced while in the 736 * inactive queue, we bump the "activation count" upwards, 737 * making it less likely that the page will be added back to 738 * the inactive queue prematurely again. Here we check the 739 * page tables (or emulated bits, if any), given the upper 740 * level VM system not knowing anything about existing 741 * references. 742 */ 743 } else if (((m->flags & PG_REFERENCED) == 0) && 744 (actcount = pmap_ts_referenced(m))) { 745 vm_page_activate(m); 746 m->act_count += (actcount + ACT_ADVANCE); 747 continue; 748 } 749 750 /* 751 * If the upper level VM system knows about any page 752 * references, we activate the page. We also set the 753 * "activation count" higher than normal so that we will less 754 * likely place pages back onto the inactive queue again. 755 */ 756 if ((m->flags & PG_REFERENCED) != 0) { 757 vm_page_flag_clear(m, PG_REFERENCED); 758 actcount = pmap_ts_referenced(m); 759 vm_page_activate(m); 760 m->act_count += (actcount + ACT_ADVANCE + 1); 761 continue; 762 } 763 764 /* 765 * If the upper level VM system doesn't know anything about 766 * the page being dirty, we have to check for it again. As 767 * far as the VM code knows, any partially dirty pages are 768 * fully dirty. 769 */ 770 if (m->dirty == 0) { 771 vm_page_test_dirty(m); 772 } else { 773 vm_page_dirty(m); 774 } 775 776 /* 777 * Invalid pages can be easily freed 778 */ 779 if (m->valid == 0) { 780 vm_pageout_page_free(m); 781 cnt.v_dfree++; 782 --page_shortage; 783 784 /* 785 * Clean pages can be placed onto the cache queue. This 786 * effectively frees them. 787 */ 788 } else if (m->dirty == 0) { 789 vm_page_cache(m); 790 --page_shortage; 791 792 /* 793 * Dirty pages need to be paged out. Note that we clean 794 * only a limited number of pages per pagedaemon pass. 795 */ 796 } else if (maxlaunder > 0) { 797 int swap_pageouts_ok; 798 struct vnode *vp = NULL; 799 struct mount *mp; 800 801 object = m->object; 802 803 if ((object->type != OBJT_SWAP) && (object->type != OBJT_DEFAULT)) { 804 swap_pageouts_ok = 1; 805 } else { 806 swap_pageouts_ok = !(defer_swap_pageouts || disable_swap_pageouts); 807 swap_pageouts_ok |= (!disable_swap_pageouts && defer_swap_pageouts && 808 vm_page_count_min()); 809 810 } 811 812 /* 813 * We don't bother paging objects that are "dead". 814 * Those objects are in a "rundown" state. 815 */ 816 if (!swap_pageouts_ok || (object->flags & OBJ_DEAD)) { 817 s = splvm(); 818 TAILQ_REMOVE(&vm_page_queues[PQ_INACTIVE].pl, m, pageq); 819 TAILQ_INSERT_TAIL(&vm_page_queues[PQ_INACTIVE].pl, m, pageq); 820 splx(s); 821 continue; 822 } 823 824 /* 825 * Presumably we have sufficient free memory to do 826 * the more sophisticated checks and locking required 827 * for vnodes. 828 * 829 * The object is already known NOT to be dead. The 830 * vget() may still block, though, because 831 * VOP_ISLOCKED() doesn't check to see if an inode 832 * (v_data) is associated with the vnode. If it isn't, 833 * vget() will load in it from disk. Worse, vget() 834 * may actually get stuck waiting on "inode" if another 835 * process is in the process of bringing the inode in. 836 * This is bad news for us either way. 837 * 838 * So for the moment we check v_data == NULL as a 839 * workaround. This means that vnodes which do not 840 * use v_data in the way we expect probably will not 841 * wind up being paged out by the pager and it will be 842 * up to the syncer to get them. That's better then 843 * us blocking here. 844 * 845 * This whole code section is bogus - we need to fix 846 * the vnode pager to handle vm_page_t's without us 847 * having to do any sophisticated VOP tests. 848 */ 849 850 if (object->type == OBJT_VNODE) { 851 vp = object->handle; 852 853 mp = NULL; 854 if (vp->v_type == VREG) 855 vn_start_write(vp, &mp, V_NOWAIT); 856 if (VOP_ISLOCKED(vp, NULL) || 857 vp->v_data == NULL || 858 vget(vp, LK_EXCLUSIVE|LK_NOOBJ, curproc)) { 859 vn_finished_write(mp); 860 if ((m->queue == PQ_INACTIVE) && 861 (m->hold_count == 0) && 862 (m->busy == 0) && 863 (m->flags & PG_BUSY) == 0) { 864 s = splvm(); 865 TAILQ_REMOVE(&vm_page_queues[PQ_INACTIVE].pl, m, pageq); 866 TAILQ_INSERT_TAIL(&vm_page_queues[PQ_INACTIVE].pl, m, pageq); 867 splx(s); 868 } 869 if (object->flags & OBJ_MIGHTBEDIRTY) 870 vnodes_skipped++; 871 continue; 872 } 873 874 /* 875 * The page might have been moved to another 876 * queue during potential blocking in vget() 877 * above. The page might have been freed and 878 * reused for another vnode. The object might 879 * have been reused for another vnode. 880 */ 881 if (m->queue != PQ_INACTIVE || 882 m->object != object || 883 object->handle != vp) { 884 if (object->flags & OBJ_MIGHTBEDIRTY) 885 vnodes_skipped++; 886 vput(vp); 887 vn_finished_write(mp); 888 continue; 889 } 890 891 /* 892 * The page may have been busied during the 893 * blocking in vput(); We don't move the 894 * page back onto the end of the queue so that 895 * statistics are more correct if we don't. 896 */ 897 if (m->busy || (m->flags & PG_BUSY)) { 898 vput(vp); 899 vn_finished_write(mp); 900 continue; 901 } 902 903 /* 904 * If the page has become held, then skip it 905 */ 906 if (m->hold_count) { 907 s = splvm(); 908 TAILQ_REMOVE(&vm_page_queues[PQ_INACTIVE].pl, m, pageq); 909 TAILQ_INSERT_TAIL(&vm_page_queues[PQ_INACTIVE].pl, m, pageq); 910 splx(s); 911 if (object->flags & OBJ_MIGHTBEDIRTY) 912 vnodes_skipped++; 913 vput(vp); 914 vn_finished_write(mp); 915 continue; 916 } 917 } 918 919 /* 920 * If a page is dirty, then it is either being washed 921 * (but not yet cleaned) or it is still in the 922 * laundry. If it is still in the laundry, then we 923 * start the cleaning operation. maxlaunder nominally 924 * counts I/O cost (seeks) rather then bytes. 925 * 926 * This operation may cluster, invalidating the 'next' 927 * pointer. To prevent an inordinate number of 928 * restarts we use our marker to remember our place. 929 */ 930 s = splvm(); 931 TAILQ_INSERT_AFTER(&vm_page_queues[PQ_INACTIVE].pl, m, &marker, pageq); 932 splx(s); 933 if (vm_pageout_clean(m) != 0) 934 --maxlaunder; 935 s = splvm(); 936 next = TAILQ_NEXT(&marker, pageq); 937 TAILQ_REMOVE(&vm_page_queues[PQ_INACTIVE].pl, &marker, pageq); 938 splx(s); 939 if (vp) { 940 vput(vp); 941 vn_finished_write(mp); 942 } 943 } 944 } 945 946 /* 947 * If we were not able to meet our target, increase actcmp 948 */ 949 950 if (vm_page_count_min()) { 951 if (vm_pageout_actcmp < ACT_MAX / 2) 952 vm_pageout_actcmp += ACT_ADVANCE; 953 } else { 954 if (vm_pageout_actcmp < ACT_DECLINE) 955 vm_pageout_actcmp = 0; 956 else 957 vm_pageout_actcmp -= ACT_DECLINE; 958 } 959 960 /* 961 * Compute the number of pages we want to try to move from the 962 * active queue to the inactive queue. 963 */ 964 965 page_shortage = vm_paging_target() + 966 cnt.v_inactive_target - cnt.v_inactive_count; 967 page_shortage += addl_page_shortage; 968 page_shortage += vm_pageout_actcmp; 969 970 /* 971 * Scan the active queue for things we can deactivate. We nominally 972 * track the per-page activity counter and use it to locate 973 * deactivation candidates. 974 */ 975 976 pcount = cnt.v_active_count; 977 m = TAILQ_FIRST(&vm_page_queues[PQ_ACTIVE].pl); 978 979 while ((m != NULL) && (pcount-- > 0) && (page_shortage > 0)) { 980 981 /* 982 * This is a consistency check, and should likely be a panic 983 * or warning. 984 */ 985 if (m->queue != PQ_ACTIVE) { 986 break; 987 } 988 989 next = TAILQ_NEXT(m, pageq); 990 /* 991 * Don't deactivate pages that are busy. 992 */ 993 if ((m->busy != 0) || 994 (m->flags & PG_BUSY) || 995 (m->hold_count != 0)) { 996 s = splvm(); 997 TAILQ_REMOVE(&vm_page_queues[PQ_ACTIVE].pl, m, pageq); 998 TAILQ_INSERT_TAIL(&vm_page_queues[PQ_ACTIVE].pl, m, pageq); 999 splx(s); 1000 m = next; 1001 continue; 1002 } 1003 1004 /* 1005 * The count for pagedaemon pages is done after checking the 1006 * page for eligibility... 1007 */ 1008 cnt.v_pdpages++; 1009 1010 /* 1011 * Check to see "how much" the page has been used. 1012 */ 1013 actcount = 0; 1014 if (m->object->ref_count != 0) { 1015 if (m->flags & PG_REFERENCED) { 1016 actcount += 1; 1017 } 1018 actcount += pmap_ts_referenced(m); 1019 if (actcount) { 1020 m->act_count += ACT_ADVANCE + actcount; 1021 if (m->act_count > ACT_MAX) 1022 m->act_count = ACT_MAX; 1023 } 1024 } 1025 1026 /* 1027 * Since we have "tested" this bit, we need to clear it now. 1028 */ 1029 vm_page_flag_clear(m, PG_REFERENCED); 1030 1031 /* 1032 * Only if an object is currently being used, do we use the 1033 * page activation count stats. 1034 */ 1035 if (actcount && (m->object->ref_count != 0)) { 1036 s = splvm(); 1037 TAILQ_REMOVE(&vm_page_queues[PQ_ACTIVE].pl, m, pageq); 1038 TAILQ_INSERT_TAIL(&vm_page_queues[PQ_ACTIVE].pl, m, pageq); 1039 splx(s); 1040 } else { 1041 m->act_count -= min(m->act_count, ACT_DECLINE); 1042 if (vm_pageout_algorithm_lru || 1043 (m->object->ref_count == 0) || 1044 (m->act_count <= vm_pageout_actcmp)) { 1045 page_shortage--; 1046 if (m->object->ref_count == 0) { 1047 vm_page_protect(m, VM_PROT_NONE); 1048 if (m->dirty == 0) 1049 vm_page_cache(m); 1050 else 1051 vm_page_deactivate(m); 1052 } else { 1053 vm_page_deactivate(m); 1054 } 1055 } else { 1056 s = splvm(); 1057 TAILQ_REMOVE(&vm_page_queues[PQ_ACTIVE].pl, m, pageq); 1058 TAILQ_INSERT_TAIL(&vm_page_queues[PQ_ACTIVE].pl, m, pageq); 1059 splx(s); 1060 } 1061 } 1062 m = next; 1063 } 1064 1065 s = splvm(); 1066 1067 /* 1068 * We try to maintain some *really* free pages, this allows interrupt 1069 * code to be guaranteed space. Since both cache and free queues 1070 * are considered basically 'free', moving pages from cache to free 1071 * does not effect other calculations. 1072 */ 1073 1074 while (cnt.v_free_count < cnt.v_free_reserved) { 1075 static int cache_rover = 0; 1076 m = vm_page_list_find(PQ_CACHE, cache_rover, FALSE); 1077 if (!m) 1078 break; 1079 if ((m->flags & (PG_BUSY|PG_UNMANAGED)) || 1080 m->busy || 1081 m->hold_count || 1082 m->wire_count) { 1083 #ifdef INVARIANTS 1084 printf("Warning: busy page %p found in cache\n", m); 1085 #endif 1086 vm_page_deactivate(m); 1087 continue; 1088 } 1089 cache_rover = (cache_rover + PQ_PRIME2) & PQ_L2_MASK; 1090 vm_pageout_page_free(m); 1091 cnt.v_dfree++; 1092 } 1093 splx(s); 1094 1095 #if !defined(NO_SWAPPING) 1096 /* 1097 * Idle process swapout -- run once per second. 1098 */ 1099 if (vm_swap_idle_enabled) { 1100 static long lsec; 1101 if (time_second != lsec) { 1102 vm_pageout_req_swapout |= VM_SWAP_IDLE; 1103 vm_req_vmdaemon(); 1104 lsec = time_second; 1105 } 1106 } 1107 #endif 1108 1109 /* 1110 * If we didn't get enough free pages, and we have skipped a vnode 1111 * in a writeable object, wakeup the sync daemon. And kick swapout 1112 * if we did not get enough free pages. 1113 */ 1114 if (vm_paging_target() > 0) { 1115 if (vnodes_skipped && vm_page_count_min()) 1116 (void) speedup_syncer(); 1117 #if !defined(NO_SWAPPING) 1118 if (vm_swap_enabled && vm_page_count_target()) { 1119 vm_req_vmdaemon(); 1120 vm_pageout_req_swapout |= VM_SWAP_NORMAL; 1121 } 1122 #endif 1123 } 1124 1125 /* 1126 * make sure that we have swap space -- if we are low on memory and 1127 * swap -- then kill the biggest process. 1128 */ 1129 if ((vm_swap_size < 64 || swap_pager_full) && vm_page_count_min()) { 1130 bigproc = NULL; 1131 bigsize = 0; 1132 lockmgr(&allproc_lock, LK_SHARED, NULL, CURPROC); 1133 for (p = allproc.lh_first; p != 0; p = p->p_list.le_next) { 1134 /* 1135 * if this is a system process, skip it 1136 */ 1137 if ((p->p_flag & P_SYSTEM) || (p->p_lock > 0) || 1138 (p->p_pid == 1) || 1139 ((p->p_pid < 48) && (vm_swap_size != 0))) { 1140 continue; 1141 } 1142 /* 1143 * if the process is in a non-running type state, 1144 * don't touch it. 1145 */ 1146 if (p->p_stat != SRUN && p->p_stat != SSLEEP) { 1147 continue; 1148 } 1149 /* 1150 * get the process size 1151 */ 1152 size = vmspace_resident_count(p->p_vmspace); 1153 /* 1154 * if the this process is bigger than the biggest one 1155 * remember it. 1156 */ 1157 if (size > bigsize) { 1158 bigproc = p; 1159 bigsize = size; 1160 } 1161 } 1162 lockmgr(&allproc_lock, LK_RELEASE, NULL, CURPROC); 1163 if (bigproc != NULL) { 1164 killproc(bigproc, "out of swap space"); 1165 bigproc->p_estcpu = 0; 1166 bigproc->p_nice = PRIO_MIN; 1167 resetpriority(bigproc); 1168 wakeup(&cnt.v_free_count); 1169 } 1170 } 1171 return force_wakeup; 1172 } 1173 1174 /* 1175 * This routine tries to maintain the pseudo LRU active queue, 1176 * so that during long periods of time where there is no paging, 1177 * that some statistic accumulation still occurs. This code 1178 * helps the situation where paging just starts to occur. 1179 */ 1180 static void 1181 vm_pageout_page_stats() 1182 { 1183 int s; 1184 vm_page_t m,next; 1185 int pcount,tpcount; /* Number of pages to check */ 1186 static int fullintervalcount = 0; 1187 int page_shortage; 1188 int s0; 1189 1190 page_shortage = 1191 (cnt.v_inactive_target + cnt.v_cache_max + cnt.v_free_min) - 1192 (cnt.v_free_count + cnt.v_inactive_count + cnt.v_cache_count); 1193 1194 if (page_shortage <= 0) 1195 return; 1196 1197 s0 = splvm(); 1198 1199 pcount = cnt.v_active_count; 1200 fullintervalcount += vm_pageout_stats_interval; 1201 if (fullintervalcount < vm_pageout_full_stats_interval) { 1202 tpcount = (vm_pageout_stats_max * cnt.v_active_count) / cnt.v_page_count; 1203 if (pcount > tpcount) 1204 pcount = tpcount; 1205 } else { 1206 fullintervalcount = 0; 1207 } 1208 1209 m = TAILQ_FIRST(&vm_page_queues[PQ_ACTIVE].pl); 1210 while ((m != NULL) && (pcount-- > 0)) { 1211 int actcount; 1212 1213 if (m->queue != PQ_ACTIVE) { 1214 break; 1215 } 1216 1217 next = TAILQ_NEXT(m, pageq); 1218 /* 1219 * Don't deactivate pages that are busy. 1220 */ 1221 if ((m->busy != 0) || 1222 (m->flags & PG_BUSY) || 1223 (m->hold_count != 0)) { 1224 s = splvm(); 1225 TAILQ_REMOVE(&vm_page_queues[PQ_ACTIVE].pl, m, pageq); 1226 TAILQ_INSERT_TAIL(&vm_page_queues[PQ_ACTIVE].pl, m, pageq); 1227 splx(s); 1228 m = next; 1229 continue; 1230 } 1231 1232 actcount = 0; 1233 if (m->flags & PG_REFERENCED) { 1234 vm_page_flag_clear(m, PG_REFERENCED); 1235 actcount += 1; 1236 } 1237 1238 actcount += pmap_ts_referenced(m); 1239 if (actcount) { 1240 m->act_count += ACT_ADVANCE + actcount; 1241 if (m->act_count > ACT_MAX) 1242 m->act_count = ACT_MAX; 1243 s = splvm(); 1244 TAILQ_REMOVE(&vm_page_queues[PQ_ACTIVE].pl, m, pageq); 1245 TAILQ_INSERT_TAIL(&vm_page_queues[PQ_ACTIVE].pl, m, pageq); 1246 splx(s); 1247 } else { 1248 if (m->act_count == 0) { 1249 /* 1250 * We turn off page access, so that we have more accurate 1251 * RSS stats. We don't do this in the normal page deactivation 1252 * when the system is loaded VM wise, because the cost of 1253 * the large number of page protect operations would be higher 1254 * than the value of doing the operation. 1255 */ 1256 vm_page_protect(m, VM_PROT_NONE); 1257 vm_page_deactivate(m); 1258 } else { 1259 m->act_count -= min(m->act_count, ACT_DECLINE); 1260 s = splvm(); 1261 TAILQ_REMOVE(&vm_page_queues[PQ_ACTIVE].pl, m, pageq); 1262 TAILQ_INSERT_TAIL(&vm_page_queues[PQ_ACTIVE].pl, m, pageq); 1263 splx(s); 1264 } 1265 } 1266 1267 m = next; 1268 } 1269 splx(s0); 1270 } 1271 1272 static int 1273 vm_pageout_free_page_calc(count) 1274 vm_size_t count; 1275 { 1276 if (count < cnt.v_page_count) 1277 return 0; 1278 /* 1279 * free_reserved needs to include enough for the largest swap pager 1280 * structures plus enough for any pv_entry structs when paging. 1281 */ 1282 if (cnt.v_page_count > 1024) 1283 cnt.v_free_min = 4 + (cnt.v_page_count - 1024) / 200; 1284 else 1285 cnt.v_free_min = 4; 1286 cnt.v_pageout_free_min = (2*MAXBSIZE)/PAGE_SIZE + 1287 cnt.v_interrupt_free_min; 1288 cnt.v_free_reserved = vm_pageout_page_count + 1289 cnt.v_pageout_free_min + (count / 768) + PQ_L2_SIZE; 1290 cnt.v_free_severe = cnt.v_free_min / 2; 1291 cnt.v_free_min += cnt.v_free_reserved; 1292 cnt.v_free_severe += cnt.v_free_reserved; 1293 return 1; 1294 } 1295 1296 1297 /* 1298 * vm_pageout is the high level pageout daemon. 1299 */ 1300 static void 1301 vm_pageout() 1302 { 1303 1304 mtx_enter(&Giant, MTX_DEF); 1305 1306 /* 1307 * Initialize some paging parameters. 1308 */ 1309 1310 cnt.v_interrupt_free_min = 2; 1311 if (cnt.v_page_count < 2000) 1312 vm_pageout_page_count = 8; 1313 1314 vm_pageout_free_page_calc(cnt.v_page_count); 1315 /* 1316 * free_reserved needs to include enough for the largest swap pager 1317 * structures plus enough for any pv_entry structs when paging. 1318 */ 1319 if (cnt.v_free_count > 6144) 1320 cnt.v_free_target = 3 * cnt.v_free_min + cnt.v_free_reserved; 1321 else 1322 cnt.v_free_target = 2 * cnt.v_free_min + cnt.v_free_reserved; 1323 1324 if (cnt.v_free_count > 2048) { 1325 cnt.v_cache_min = cnt.v_free_target; 1326 cnt.v_cache_max = 2 * cnt.v_cache_min; 1327 cnt.v_inactive_target = (3 * cnt.v_free_target) / 2; 1328 } else { 1329 cnt.v_cache_min = 0; 1330 cnt.v_cache_max = 0; 1331 cnt.v_inactive_target = cnt.v_free_count / 4; 1332 } 1333 if (cnt.v_inactive_target > cnt.v_free_count / 3) 1334 cnt.v_inactive_target = cnt.v_free_count / 3; 1335 1336 /* XXX does not really belong here */ 1337 if (vm_page_max_wired == 0) 1338 vm_page_max_wired = cnt.v_free_count / 3; 1339 1340 if (vm_pageout_stats_max == 0) 1341 vm_pageout_stats_max = cnt.v_free_target; 1342 1343 /* 1344 * Set interval in seconds for stats scan. 1345 */ 1346 if (vm_pageout_stats_interval == 0) 1347 vm_pageout_stats_interval = 5; 1348 if (vm_pageout_full_stats_interval == 0) 1349 vm_pageout_full_stats_interval = vm_pageout_stats_interval * 4; 1350 1351 1352 /* 1353 * Set maximum free per pass 1354 */ 1355 if (vm_pageout_stats_free_max == 0) 1356 vm_pageout_stats_free_max = 5; 1357 1358 max_page_launder = (cnt.v_page_count > 1800 ? 32 : 16); 1359 1360 curproc->p_flag |= P_BUFEXHAUST; 1361 swap_pager_swap_init(); 1362 /* 1363 * The pageout daemon is never done, so loop forever. 1364 */ 1365 while (TRUE) { 1366 int error; 1367 int s = splvm(); 1368 1369 /* 1370 * If we have enough free memory, wakeup waiters. Do 1371 * not clear vm_pages_needed until we reach our target, 1372 * otherwise we may be woken up over and over again and 1373 * waste a lot of cpu. 1374 */ 1375 if (vm_pages_needed && !vm_page_count_min()) { 1376 if (vm_paging_needed() <= 0) 1377 vm_pages_needed = 0; 1378 wakeup(&cnt.v_free_count); 1379 } 1380 if (vm_pages_needed) { 1381 /* 1382 * Still not done, sleep a bit and go again 1383 */ 1384 tsleep(&vm_pages_needed, PVM, "psleep", hz/2); 1385 } else { 1386 /* 1387 * Good enough, sleep & handle stats 1388 */ 1389 error = tsleep(&vm_pages_needed, 1390 PVM, "psleep", vm_pageout_stats_interval * hz); 1391 if (error && !vm_pages_needed) { 1392 if (vm_pageout_actcmp > 0) 1393 --vm_pageout_actcmp; 1394 splx(s); 1395 vm_pageout_page_stats(); 1396 continue; 1397 } 1398 } 1399 1400 if (vm_pages_needed) 1401 cnt.v_pdwakeups++; 1402 splx(s); 1403 vm_pageout_scan(); 1404 vm_pageout_deficit = 0; 1405 } 1406 } 1407 1408 void 1409 pagedaemon_wakeup() 1410 { 1411 if (!vm_pages_needed && curproc != pageproc) { 1412 vm_pages_needed++; 1413 wakeup(&vm_pages_needed); 1414 } 1415 } 1416 1417 #if !defined(NO_SWAPPING) 1418 static void 1419 vm_req_vmdaemon() 1420 { 1421 static int lastrun = 0; 1422 1423 if ((ticks > (lastrun + hz)) || (ticks < lastrun)) { 1424 wakeup(&vm_daemon_needed); 1425 lastrun = ticks; 1426 } 1427 } 1428 1429 static void 1430 vm_daemon() 1431 { 1432 struct proc *p; 1433 1434 mtx_enter(&Giant, MTX_DEF); 1435 1436 while (TRUE) { 1437 tsleep(&vm_daemon_needed, PPAUSE, "psleep", 0); 1438 if (vm_pageout_req_swapout) { 1439 swapout_procs(vm_pageout_req_swapout); 1440 vm_pageout_req_swapout = 0; 1441 } 1442 /* 1443 * scan the processes for exceeding their rlimits or if 1444 * process is swapped out -- deactivate pages 1445 */ 1446 1447 lockmgr(&allproc_lock, LK_SHARED, NULL, CURPROC); 1448 for (p = allproc.lh_first; p != 0; p = p->p_list.le_next) { 1449 vm_pindex_t limit, size; 1450 1451 /* 1452 * if this is a system process or if we have already 1453 * looked at this process, skip it. 1454 */ 1455 if (p->p_flag & (P_SYSTEM | P_WEXIT)) { 1456 continue; 1457 } 1458 /* 1459 * if the process is in a non-running type state, 1460 * don't touch it. 1461 */ 1462 if (p->p_stat != SRUN && p->p_stat != SSLEEP) { 1463 continue; 1464 } 1465 /* 1466 * get a limit 1467 */ 1468 limit = OFF_TO_IDX( 1469 qmin(p->p_rlimit[RLIMIT_RSS].rlim_cur, 1470 p->p_rlimit[RLIMIT_RSS].rlim_max)); 1471 1472 /* 1473 * let processes that are swapped out really be 1474 * swapped out set the limit to nothing (will force a 1475 * swap-out.) 1476 */ 1477 if ((p->p_flag & P_INMEM) == 0) 1478 limit = 0; /* XXX */ 1479 1480 size = vmspace_resident_count(p->p_vmspace); 1481 if (limit >= 0 && size >= limit) { 1482 vm_pageout_map_deactivate_pages( 1483 &p->p_vmspace->vm_map, limit); 1484 } 1485 } 1486 lockmgr(&allproc_lock, LK_RELEASE, NULL, CURPROC); 1487 } 1488 } 1489 #endif 1490