Add some temporary debugging.
[dragonfly.git] / sys / vm / vm_pageout.c
CommitLineData
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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: src/sys/vm/vm_pageout.c,v 1.151.2.15 2002/12/29 18:21:04 dillon Exp $
dadab5e9 69 * $DragonFly: src/sys/vm/vm_pageout.c,v 1.4 2003/06/25 03:56:13 dillon Exp $
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70 */
71
72/*
73 * The proverbial page-out daemon.
74 */
75
76#include "opt_vm.h"
77#include <sys/param.h>
78#include <sys/systm.h>
79#include <sys/kernel.h>
80#include <sys/proc.h>
81#include <sys/kthread.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/*
100 * System initialization
101 */
102
103/* the kernel process "vm_pageout"*/
104static void vm_pageout __P((void));
105static int vm_pageout_clean __P((vm_page_t));
106static void vm_pageout_scan __P((int pass));
107static int vm_pageout_free_page_calc __P((vm_size_t count));
bc6dffab 108struct thread *pagethread;
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109
110static struct kproc_desc page_kp = {
111 "pagedaemon",
112 vm_pageout,
bc6dffab 113 &pagethread
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114};
115SYSINIT(pagedaemon, SI_SUB_KTHREAD_PAGE, SI_ORDER_FIRST, kproc_start, &page_kp)
116
117#if !defined(NO_SWAPPING)
118/* the kernel process "vm_daemon"*/
119static void vm_daemon __P((void));
bc6dffab 120static struct thread *vmthread;
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121
122static struct kproc_desc vm_kp = {
123 "vmdaemon",
124 vm_daemon,
bc6dffab 125 &vmthread
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126};
127SYSINIT(vmdaemon, SI_SUB_KTHREAD_VM, SI_ORDER_FIRST, kproc_start, &vm_kp)
128#endif
129
130
131int vm_pages_needed=0; /* Event on which pageout daemon sleeps */
132int vm_pageout_deficit=0; /* Estimated number of pages deficit */
133int vm_pageout_pages_needed=0; /* flag saying that the pageout daemon needs pages */
134
135#if !defined(NO_SWAPPING)
136static int vm_pageout_req_swapout; /* XXX */
137static int vm_daemon_needed;
138#endif
139extern int vm_swap_size;
140static int vm_max_launder = 32;
141static int vm_pageout_stats_max=0, vm_pageout_stats_interval = 0;
142static int vm_pageout_full_stats_interval = 0;
143static int vm_pageout_stats_free_max=0, vm_pageout_algorithm=0;
144static int defer_swap_pageouts=0;
145static int disable_swap_pageouts=0;
146
147#if defined(NO_SWAPPING)
148static int vm_swap_enabled=0;
149static int vm_swap_idle_enabled=0;
150#else
151static int vm_swap_enabled=1;
152static int vm_swap_idle_enabled=0;
153#endif
154
155SYSCTL_INT(_vm, VM_PAGEOUT_ALGORITHM, pageout_algorithm,
156 CTLFLAG_RW, &vm_pageout_algorithm, 0, "LRU page mgmt");
157
158SYSCTL_INT(_vm, OID_AUTO, max_launder,
159 CTLFLAG_RW, &vm_max_launder, 0, "Limit dirty flushes in pageout");
160
161SYSCTL_INT(_vm, OID_AUTO, pageout_stats_max,
162 CTLFLAG_RW, &vm_pageout_stats_max, 0, "Max pageout stats scan length");
163
164SYSCTL_INT(_vm, OID_AUTO, pageout_full_stats_interval,
165 CTLFLAG_RW, &vm_pageout_full_stats_interval, 0, "Interval for full stats scan");
166
167SYSCTL_INT(_vm, OID_AUTO, pageout_stats_interval,
168 CTLFLAG_RW, &vm_pageout_stats_interval, 0, "Interval for partial stats scan");
169
170SYSCTL_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)
174SYSCTL_INT(_vm, VM_SWAPPING_ENABLED, swap_enabled,
175 CTLFLAG_RD, &vm_swap_enabled, 0, "");
176SYSCTL_INT(_vm, OID_AUTO, swap_idle_enabled,
177 CTLFLAG_RD, &vm_swap_idle_enabled, 0, "");
178#else
179SYSCTL_INT(_vm, VM_SWAPPING_ENABLED, swap_enabled,
180 CTLFLAG_RW, &vm_swap_enabled, 0, "Enable entire process swapout");
181SYSCTL_INT(_vm, OID_AUTO, swap_idle_enabled,
182 CTLFLAG_RW, &vm_swap_idle_enabled, 0, "Allow swapout on idle criteria");
183#endif
184
185SYSCTL_INT(_vm, OID_AUTO, defer_swapspace_pageouts,
186 CTLFLAG_RW, &defer_swap_pageouts, 0, "Give preference to dirty pages in mem");
187
188SYSCTL_INT(_vm, OID_AUTO, disable_swapspace_pageouts,
189 CTLFLAG_RW, &disable_swap_pageouts, 0, "Disallow swapout of dirty pages");
190
191static int pageout_lock_miss;
192SYSCTL_INT(_vm, OID_AUTO, pageout_lock_miss,
193 CTLFLAG_RD, &pageout_lock_miss, 0, "vget() lock misses during pageout");
194
195#define VM_PAGEOUT_PAGE_COUNT 16
196int vm_pageout_page_count = VM_PAGEOUT_PAGE_COUNT;
197
198int vm_page_max_wired; /* XXX max # of wired pages system-wide */
199
200#if !defined(NO_SWAPPING)
201typedef void freeer_fcn_t __P((vm_map_t, vm_object_t, vm_pindex_t, int));
202static void vm_pageout_map_deactivate_pages __P((vm_map_t, vm_pindex_t));
203static freeer_fcn_t vm_pageout_object_deactivate_pages;
204static void vm_req_vmdaemon __P((void));
205#endif
206static void vm_pageout_page_stats(void);
207
208/*
209 * vm_pageout_clean:
210 *
211 * Clean the page and remove it from the laundry.
212 *
213 * We set the busy bit to cause potential page faults on this page to
214 * block. Note the careful timing, however, the busy bit isn't set till
215 * late and we cannot do anything that will mess with the page.
216 */
217
218static int
219vm_pageout_clean(m)
220 vm_page_t m;
221{
222 register vm_object_t object;
223 vm_page_t mc[2*vm_pageout_page_count];
224 int pageout_count;
225 int ib, is, page_base;
226 vm_pindex_t pindex = m->pindex;
227
228 object = m->object;
229
230 /*
231 * It doesn't cost us anything to pageout OBJT_DEFAULT or OBJT_SWAP
232 * with the new swapper, but we could have serious problems paging
233 * out other object types if there is insufficient memory.
234 *
235 * Unfortunately, checking free memory here is far too late, so the
236 * check has been moved up a procedural level.
237 */
238
239 /*
240 * Don't mess with the page if it's busy, held, or special
241 */
242 if ((m->hold_count != 0) ||
243 ((m->busy != 0) || (m->flags & (PG_BUSY|PG_UNMANAGED)))) {
244 return 0;
245 }
246
247 mc[vm_pageout_page_count] = m;
248 pageout_count = 1;
249 page_base = vm_pageout_page_count;
250 ib = 1;
251 is = 1;
252
253 /*
254 * Scan object for clusterable pages.
255 *
256 * We can cluster ONLY if: ->> the page is NOT
257 * clean, wired, busy, held, or mapped into a
258 * buffer, and one of the following:
259 * 1) The page is inactive, or a seldom used
260 * active page.
261 * -or-
262 * 2) we force the issue.
263 *
264 * During heavy mmap/modification loads the pageout
265 * daemon can really fragment the underlying file
266 * due to flushing pages out of order and not trying
267 * align the clusters (which leave sporatic out-of-order
268 * holes). To solve this problem we do the reverse scan
269 * first and attempt to align our cluster, then do a
270 * forward scan if room remains.
271 */
272
273more:
274 while (ib && pageout_count < vm_pageout_page_count) {
275 vm_page_t p;
276
277 if (ib > pindex) {
278 ib = 0;
279 break;
280 }
281
282 if ((p = vm_page_lookup(object, pindex - ib)) == NULL) {
283 ib = 0;
284 break;
285 }
286 if (((p->queue - p->pc) == PQ_CACHE) ||
287 (p->flags & (PG_BUSY|PG_UNMANAGED)) || p->busy) {
288 ib = 0;
289 break;
290 }
291 vm_page_test_dirty(p);
292 if ((p->dirty & p->valid) == 0 ||
293 p->queue != PQ_INACTIVE ||
294 p->wire_count != 0 || /* may be held by buf cache */
295 p->hold_count != 0) { /* may be undergoing I/O */
296 ib = 0;
297 break;
298 }
299 mc[--page_base] = p;
300 ++pageout_count;
301 ++ib;
302 /*
303 * alignment boundry, stop here and switch directions. Do
304 * not clear ib.
305 */
306 if ((pindex - (ib - 1)) % vm_pageout_page_count == 0)
307 break;
308 }
309
310 while (pageout_count < vm_pageout_page_count &&
311 pindex + is < object->size) {
312 vm_page_t p;
313
314 if ((p = vm_page_lookup(object, pindex + is)) == NULL)
315 break;
316 if (((p->queue - p->pc) == PQ_CACHE) ||
317 (p->flags & (PG_BUSY|PG_UNMANAGED)) || p->busy) {
318 break;
319 }
320 vm_page_test_dirty(p);
321 if ((p->dirty & p->valid) == 0 ||
322 p->queue != PQ_INACTIVE ||
323 p->wire_count != 0 || /* may be held by buf cache */
324 p->hold_count != 0) { /* may be undergoing I/O */
325 break;
326 }
327 mc[page_base + pageout_count] = p;
328 ++pageout_count;
329 ++is;
330 }
331
332 /*
333 * If we exhausted our forward scan, continue with the reverse scan
334 * when possible, even past a page boundry. This catches boundry
335 * conditions.
336 */
337 if (ib && pageout_count < vm_pageout_page_count)
338 goto more;
339
340 /*
341 * we allow reads during pageouts...
342 */
343 return vm_pageout_flush(&mc[page_base], pageout_count, 0);
344}
345
346/*
347 * vm_pageout_flush() - launder the given pages
348 *
349 * The given pages are laundered. Note that we setup for the start of
350 * I/O ( i.e. busy the page ), mark it read-only, and bump the object
351 * reference count all in here rather then in the parent. If we want
352 * the parent to do more sophisticated things we may have to change
353 * the ordering.
354 */
355
356int
357vm_pageout_flush(mc, count, flags)
358 vm_page_t *mc;
359 int count;
360 int flags;
361{
362 register vm_object_t object;
363 int pageout_status[count];
364 int numpagedout = 0;
365 int i;
366
367 /*
368 * Initiate I/O. Bump the vm_page_t->busy counter and
369 * mark the pages read-only.
370 *
371 * We do not have to fixup the clean/dirty bits here... we can
372 * allow the pager to do it after the I/O completes.
373 */
374
375 for (i = 0; i < count; i++) {
376 KASSERT(mc[i]->valid == VM_PAGE_BITS_ALL, ("vm_pageout_flush page %p index %d/%d: partially invalid page", mc[i], i, count));
377 vm_page_io_start(mc[i]);
378 vm_page_protect(mc[i], VM_PROT_READ);
379 }
380
381 object = mc[0]->object;
382 vm_object_pip_add(object, count);
383
384 vm_pager_put_pages(object, mc, count,
385 (flags | ((object == kernel_object) ? VM_PAGER_PUT_SYNC : 0)),
386 pageout_status);
387
388 for (i = 0; i < count; i++) {
389 vm_page_t mt = mc[i];
390
391 switch (pageout_status[i]) {
392 case VM_PAGER_OK:
393 numpagedout++;
394 break;
395 case VM_PAGER_PEND:
396 numpagedout++;
397 break;
398 case VM_PAGER_BAD:
399 /*
400 * Page outside of range of object. Right now we
401 * essentially lose the changes by pretending it
402 * worked.
403 */
404 pmap_clear_modify(mt);
405 vm_page_undirty(mt);
406 break;
407 case VM_PAGER_ERROR:
408 case VM_PAGER_FAIL:
409 /*
410 * If page couldn't be paged out, then reactivate the
411 * page so it doesn't clog the inactive list. (We
412 * will try paging out it again later).
413 */
414 vm_page_activate(mt);
415 break;
416 case VM_PAGER_AGAIN:
417 break;
418 }
419
420 /*
421 * If the operation is still going, leave the page busy to
422 * block all other accesses. Also, leave the paging in
423 * progress indicator set so that we don't attempt an object
424 * collapse.
425 */
426 if (pageout_status[i] != VM_PAGER_PEND) {
427 vm_object_pip_wakeup(object);
428 vm_page_io_finish(mt);
429 if (!vm_page_count_severe() || !vm_page_try_to_cache(mt))
430 vm_page_protect(mt, VM_PROT_READ);
431 }
432 }
433 return numpagedout;
434}
435
436#if !defined(NO_SWAPPING)
437/*
438 * vm_pageout_object_deactivate_pages
439 *
440 * deactivate enough pages to satisfy the inactive target
441 * requirements or if vm_page_proc_limit is set, then
442 * deactivate all of the pages in the object and its
443 * backing_objects.
444 *
445 * The object and map must be locked.
446 */
447static void
448vm_pageout_object_deactivate_pages(map, object, desired, map_remove_only)
449 vm_map_t map;
450 vm_object_t object;
451 vm_pindex_t desired;
452 int map_remove_only;
453{
454 register vm_page_t p, next;
455 int rcount;
456 int remove_mode;
457 int s;
458
459 if (object->type == OBJT_DEVICE || object->type == OBJT_PHYS)
460 return;
461
462 while (object) {
463 if (pmap_resident_count(vm_map_pmap(map)) <= desired)
464 return;
465 if (object->paging_in_progress)
466 return;
467
468 remove_mode = map_remove_only;
469 if (object->shadow_count > 1)
470 remove_mode = 1;
471 /*
472 * scan the objects entire memory queue
473 */
474 rcount = object->resident_page_count;
475 p = TAILQ_FIRST(&object->memq);
476 while (p && (rcount-- > 0)) {
477 int actcount;
478 if (pmap_resident_count(vm_map_pmap(map)) <= desired)
479 return;
480 next = TAILQ_NEXT(p, listq);
481 cnt.v_pdpages++;
482 if (p->wire_count != 0 ||
483 p->hold_count != 0 ||
484 p->busy != 0 ||
485 (p->flags & (PG_BUSY|PG_UNMANAGED)) ||
486 !pmap_page_exists_quick(vm_map_pmap(map), p)) {
487 p = next;
488 continue;
489 }
490
491 actcount = pmap_ts_referenced(p);
492 if (actcount) {
493 vm_page_flag_set(p, PG_REFERENCED);
494 } else if (p->flags & PG_REFERENCED) {
495 actcount = 1;
496 }
497
498 if ((p->queue != PQ_ACTIVE) &&
499 (p->flags & PG_REFERENCED)) {
500 vm_page_activate(p);
501 p->act_count += actcount;
502 vm_page_flag_clear(p, PG_REFERENCED);
503 } else if (p->queue == PQ_ACTIVE) {
504 if ((p->flags & PG_REFERENCED) == 0) {
505 p->act_count -= min(p->act_count, ACT_DECLINE);
506 if (!remove_mode && (vm_pageout_algorithm || (p->act_count == 0))) {
507 vm_page_protect(p, VM_PROT_NONE);
508 vm_page_deactivate(p);
509 } else {
510 s = splvm();
511 TAILQ_REMOVE(&vm_page_queues[PQ_ACTIVE].pl, p, pageq);
512 TAILQ_INSERT_TAIL(&vm_page_queues[PQ_ACTIVE].pl, p, pageq);
513 splx(s);
514 }
515 } else {
516 vm_page_activate(p);
517 vm_page_flag_clear(p, PG_REFERENCED);
518 if (p->act_count < (ACT_MAX - ACT_ADVANCE))
519 p->act_count += ACT_ADVANCE;
520 s = splvm();
521 TAILQ_REMOVE(&vm_page_queues[PQ_ACTIVE].pl, p, pageq);
522 TAILQ_INSERT_TAIL(&vm_page_queues[PQ_ACTIVE].pl, p, pageq);
523 splx(s);
524 }
525 } else if (p->queue == PQ_INACTIVE) {
526 vm_page_protect(p, VM_PROT_NONE);
527 }
528 p = next;
529 }
530 object = object->backing_object;
531 }
532 return;
533}
534
535/*
536 * deactivate some number of pages in a map, try to do it fairly, but
537 * that is really hard to do.
538 */
539static void
540vm_pageout_map_deactivate_pages(map, desired)
541 vm_map_t map;
542 vm_pindex_t desired;
543{
544 vm_map_entry_t tmpe;
545 vm_object_t obj, bigobj;
546 int nothingwired;
547
dadab5e9 548 if (lockmgr(&map->lock, LK_EXCLUSIVE | LK_NOWAIT, (void *)0, curthread)) {
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549 return;
550 }
551
552 bigobj = NULL;
553 nothingwired = TRUE;
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 if (tmpe->wired_count > 0)
570 nothingwired = FALSE;
571 tmpe = tmpe->next;
572 }
573
574 if (bigobj)
575 vm_pageout_object_deactivate_pages(map, bigobj, desired, 0);
576
577 /*
578 * Next, hunt around for other pages to deactivate. We actually
579 * do this search sort of wrong -- .text first is not the best idea.
580 */
581 tmpe = map->header.next;
582 while (tmpe != &map->header) {
583 if (pmap_resident_count(vm_map_pmap(map)) <= desired)
584 break;
585 if ((tmpe->eflags & MAP_ENTRY_IS_SUB_MAP) == 0) {
586 obj = tmpe->object.vm_object;
587 if (obj)
588 vm_pageout_object_deactivate_pages(map, obj, desired, 0);
589 }
590 tmpe = tmpe->next;
591 };
592
593 /*
594 * Remove all mappings if a process is swapped out, this will free page
595 * table pages.
596 */
597 if (desired == 0 && nothingwired)
598 pmap_remove(vm_map_pmap(map),
599 VM_MIN_ADDRESS, VM_MAXUSER_ADDRESS);
600 vm_map_unlock(map);
601 return;
602}
603#endif
604
605/*
606 * Don't try to be fancy - being fancy can lead to VOP_LOCK's and therefore
607 * to vnode deadlocks. We only do it for OBJT_DEFAULT and OBJT_SWAP objects
608 * which we know can be trivially freed.
609 */
610
611void
612vm_pageout_page_free(vm_page_t m) {
613 vm_object_t object = m->object;
614 int type = object->type;
615
616 if (type == OBJT_SWAP || type == OBJT_DEFAULT)
617 vm_object_reference(object);
618 vm_page_busy(m);
619 vm_page_protect(m, VM_PROT_NONE);
620 vm_page_free(m);
621 if (type == OBJT_SWAP || type == OBJT_DEFAULT)
622 vm_object_deallocate(object);
623}
624
625/*
626 * vm_pageout_scan does the dirty work for the pageout daemon.
627 */
628static void
629vm_pageout_scan(int pass)
630{
631 vm_page_t m, next;
632 struct vm_page marker;
633 int page_shortage, maxscan, pcount;
634 int addl_page_shortage, addl_page_shortage_init;
635 struct proc *p, *bigproc;
636 vm_offset_t size, bigsize;
637 vm_object_t object;
638 int actcount;
639 int vnodes_skipped = 0;
640 int maxlaunder;
641 int s;
642
643 /*
644 * Do whatever cleanup that the pmap code can.
645 */
646 pmap_collect();
647
648 addl_page_shortage_init = vm_pageout_deficit;
649 vm_pageout_deficit = 0;
650
651 /*
652 * Calculate the number of pages we want to either free or move
653 * to the cache.
654 */
655 page_shortage = vm_paging_target() + addl_page_shortage_init;
656
657 /*
658 * Initialize our marker
659 */
660 bzero(&marker, sizeof(marker));
661 marker.flags = PG_BUSY | PG_FICTITIOUS | PG_MARKER;
662 marker.queue = PQ_INACTIVE;
663 marker.wire_count = 1;
664
665 /*
666 * Start scanning the inactive queue for pages we can move to the
667 * cache or free. The scan will stop when the target is reached or
668 * we have scanned the entire inactive queue. Note that m->act_count
669 * is not used to form decisions for the inactive queue, only for the
670 * active queue.
671 *
672 * maxlaunder limits the number of dirty pages we flush per scan.
673 * For most systems a smaller value (16 or 32) is more robust under
674 * extreme memory and disk pressure because any unnecessary writes
675 * to disk can result in extreme performance degredation. However,
676 * systems with excessive dirty pages (especially when MAP_NOSYNC is
677 * used) will die horribly with limited laundering. If the pageout
678 * daemon cannot clean enough pages in the first pass, we let it go
679 * all out in succeeding passes.
680 */
681 if ((maxlaunder = vm_max_launder) <= 1)
682 maxlaunder = 1;
683 if (pass)
684 maxlaunder = 10000;
685
686rescan0:
687 addl_page_shortage = addl_page_shortage_init;
688 maxscan = cnt.v_inactive_count;
689 for (m = TAILQ_FIRST(&vm_page_queues[PQ_INACTIVE].pl);
690 m != NULL && maxscan-- > 0 && page_shortage > 0;
691 m = next) {
692
693 cnt.v_pdpages++;
694
695 if (m->queue != PQ_INACTIVE) {
696 goto rescan0;
697 }
698
699 next = TAILQ_NEXT(m, pageq);
700
701 /*
702 * skip marker pages
703 */
704 if (m->flags & PG_MARKER)
705 continue;
706
707 /*
708 * A held page may be undergoing I/O, so skip it.
709 */
710 if (m->hold_count) {
711 s = splvm();
712 TAILQ_REMOVE(&vm_page_queues[PQ_INACTIVE].pl, m, pageq);
713 TAILQ_INSERT_TAIL(&vm_page_queues[PQ_INACTIVE].pl, m, pageq);
714 splx(s);
715 addl_page_shortage++;
716 continue;
717 }
718 /*
719 * Dont mess with busy pages, keep in the front of the
720 * queue, most likely are being paged out.
721 */
722 if (m->busy || (m->flags & PG_BUSY)) {
723 addl_page_shortage++;
724 continue;
725 }
726
727 /*
728 * If the object is not being used, we ignore previous
729 * references.
730 */
731 if (m->object->ref_count == 0) {
732 vm_page_flag_clear(m, PG_REFERENCED);
733 pmap_clear_reference(m);
734
735 /*
736 * Otherwise, if the page has been referenced while in the
737 * inactive queue, we bump the "activation count" upwards,
738 * making it less likely that the page will be added back to
739 * the inactive queue prematurely again. Here we check the
740 * page tables (or emulated bits, if any), given the upper
741 * level VM system not knowing anything about existing
742 * references.
743 */
744 } else if (((m->flags & PG_REFERENCED) == 0) &&
745 (actcount = pmap_ts_referenced(m))) {
746 vm_page_activate(m);
747 m->act_count += (actcount + ACT_ADVANCE);
748 continue;
749 }
750
751 /*
752 * If the upper level VM system knows about any page
753 * references, we activate the page. We also set the
754 * "activation count" higher than normal so that we will less
755 * likely place pages back onto the inactive queue again.
756 */
757 if ((m->flags & PG_REFERENCED) != 0) {
758 vm_page_flag_clear(m, PG_REFERENCED);
759 actcount = pmap_ts_referenced(m);
760 vm_page_activate(m);
761 m->act_count += (actcount + ACT_ADVANCE + 1);
762 continue;
763 }
764
765 /*
766 * If the upper level VM system doesn't know anything about
767 * the page being dirty, we have to check for it again. As
768 * far as the VM code knows, any partially dirty pages are
769 * fully dirty.
770 */
771 if (m->dirty == 0) {
772 vm_page_test_dirty(m);
773 } else {
774 vm_page_dirty(m);
775 }
776
777 /*
778 * Invalid pages can be easily freed
779 */
780 if (m->valid == 0) {
781 vm_pageout_page_free(m);
782 cnt.v_dfree++;
783 --page_shortage;
784
785 /*
786 * Clean pages can be placed onto the cache queue. This
787 * effectively frees them.
788 */
789 } else if (m->dirty == 0) {
790 /*
791 * Clean pages can be immediately freed to the cache.
792 */
793 vm_page_cache(m);
794 --page_shortage;
795 } else if ((m->flags & PG_WINATCFLS) == 0 && pass == 0) {
796 /*
797 * Dirty pages need to be paged out, but flushing
798 * a page is extremely expensive verses freeing
799 * a clean page. Rather then artificially limiting
800 * the number of pages we can flush, we instead give
801 * dirty pages extra priority on the inactive queue
802 * by forcing them to be cycled through the queue
803 * twice before being flushed, after which the
804 * (now clean) page will cycle through once more
805 * before being freed. This significantly extends
806 * the thrash point for a heavily loaded machine.
807 */
808 s = splvm();
809 vm_page_flag_set(m, PG_WINATCFLS);
810 TAILQ_REMOVE(&vm_page_queues[PQ_INACTIVE].pl, m, pageq);
811 TAILQ_INSERT_TAIL(&vm_page_queues[PQ_INACTIVE].pl, m, pageq);
812 splx(s);
813 } else if (maxlaunder > 0) {
814 /*
815 * We always want to try to flush some dirty pages if
816 * we encounter them, to keep the system stable.
817 * Normally this number is small, but under extreme
818 * pressure where there are insufficient clean pages
819 * on the inactive queue, we may have to go all out.
820 */
821 int swap_pageouts_ok;
822 struct vnode *vp = NULL;
823
824 object = m->object;
825
826 if ((object->type != OBJT_SWAP) && (object->type != OBJT_DEFAULT)) {
827 swap_pageouts_ok = 1;
828 } else {
829 swap_pageouts_ok = !(defer_swap_pageouts || disable_swap_pageouts);
830 swap_pageouts_ok |= (!disable_swap_pageouts && defer_swap_pageouts &&
831 vm_page_count_min());
832
833 }
834
835 /*
836 * We don't bother paging objects that are "dead".
837 * Those objects are in a "rundown" state.
838 */
839 if (!swap_pageouts_ok || (object->flags & OBJ_DEAD)) {
840 s = splvm();
841 TAILQ_REMOVE(&vm_page_queues[PQ_INACTIVE].pl, m, pageq);
842 TAILQ_INSERT_TAIL(&vm_page_queues[PQ_INACTIVE].pl, m, pageq);
843 splx(s);
844 continue;
845 }
846
847 /*
848 * The object is already known NOT to be dead. It
849 * is possible for the vget() to block the whole
850 * pageout daemon, but the new low-memory handling
851 * code should prevent it.
852 *
853 * The previous code skipped locked vnodes and, worse,
854 * reordered pages in the queue. This results in
855 * completely non-deterministic operation because,
856 * quite often, a vm_fault has initiated an I/O and
857 * is holding a locked vnode at just the point where
858 * the pageout daemon is woken up.
859 *
860 * We can't wait forever for the vnode lock, we might
861 * deadlock due to a vn_read() getting stuck in
862 * vm_wait while holding this vnode. We skip the
863 * vnode if we can't get it in a reasonable amount
864 * of time.
865 */
866
867 if (object->type == OBJT_VNODE) {
868 vp = object->handle;
869
dadab5e9 870 if (vget(vp, LK_EXCLUSIVE|LK_NOOBJ|LK_TIMELOCK, curthread)) {
984263bc
MD
871 ++pageout_lock_miss;
872 if (object->flags & OBJ_MIGHTBEDIRTY)
873 vnodes_skipped++;
874 continue;
875 }
876
877 /*
878 * The page might have been moved to another
879 * queue during potential blocking in vget()
880 * above. The page might have been freed and
881 * reused for another vnode. The object might
882 * have been reused for another vnode.
883 */
884 if (m->queue != PQ_INACTIVE ||
885 m->object != object ||
886 object->handle != vp) {
887 if (object->flags & OBJ_MIGHTBEDIRTY)
888 vnodes_skipped++;
889 vput(vp);
890 continue;
891 }
892
893 /*
894 * The page may have been busied during the
895 * blocking in vput(); We don't move the
896 * page back onto the end of the queue so that
897 * statistics are more correct if we don't.
898 */
899 if (m->busy || (m->flags & PG_BUSY)) {
900 vput(vp);
901 continue;
902 }
903
904 /*
905 * If the page has become held it might
906 * be undergoing I/O, so skip it
907 */
908 if (m->hold_count) {
909 s = splvm();
910 TAILQ_REMOVE(&vm_page_queues[PQ_INACTIVE].pl, m, pageq);
911 TAILQ_INSERT_TAIL(&vm_page_queues[PQ_INACTIVE].pl, m, pageq);
912 splx(s);
913 if (object->flags & OBJ_MIGHTBEDIRTY)
914 vnodes_skipped++;
915 vput(vp);
916 continue;
917 }
918 }
919
920 /*
921 * If a page is dirty, then it is either being washed
922 * (but not yet cleaned) or it is still in the
923 * laundry. If it is still in the laundry, then we
924 * start the cleaning operation.
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 * decrement page_shortage on success to account for
931 * the (future) cleaned page. Otherwise we could wind
932 * up laundering or cleaning too many pages.
933 */
934 s = splvm();
935 TAILQ_INSERT_AFTER(&vm_page_queues[PQ_INACTIVE].pl, m, &marker, pageq);
936 splx(s);
937 if (vm_pageout_clean(m) != 0) {
938 --page_shortage;
939 --maxlaunder;
940 }
941 s = splvm();
942 next = TAILQ_NEXT(&marker, pageq);
943 TAILQ_REMOVE(&vm_page_queues[PQ_INACTIVE].pl, &marker, pageq);
944 splx(s);
945 if (vp != NULL)
946 vput(vp);
947 }
948 }
949
950 /*
951 * Compute the number of pages we want to try to move from the
952 * active queue to the inactive queue.
953 */
954 page_shortage = vm_paging_target() +
955 cnt.v_inactive_target - cnt.v_inactive_count;
956 page_shortage += addl_page_shortage;
957
958 /*
959 * Scan the active queue for things we can deactivate. We nominally
960 * track the per-page activity counter and use it to locate
961 * deactivation candidates.
962 */
963
964 pcount = cnt.v_active_count;
965 m = TAILQ_FIRST(&vm_page_queues[PQ_ACTIVE].pl);
966
967 while ((m != NULL) && (pcount-- > 0) && (page_shortage > 0)) {
968
969 /*
970 * This is a consistency check, and should likely be a panic
971 * or warning.
972 */
973 if (m->queue != PQ_ACTIVE) {
974 break;
975 }
976
977 next = TAILQ_NEXT(m, pageq);
978 /*
979 * Don't deactivate pages that are busy.
980 */
981 if ((m->busy != 0) ||
982 (m->flags & PG_BUSY) ||
983 (m->hold_count != 0)) {
984 s = splvm();
985 TAILQ_REMOVE(&vm_page_queues[PQ_ACTIVE].pl, m, pageq);
986 TAILQ_INSERT_TAIL(&vm_page_queues[PQ_ACTIVE].pl, m, pageq);
987 splx(s);
988 m = next;
989 continue;
990 }
991
992 /*
993 * The count for pagedaemon pages is done after checking the
994 * page for eligibility...
995 */
996 cnt.v_pdpages++;
997
998 /*
999 * Check to see "how much" the page has been used.
1000 */
1001 actcount = 0;
1002 if (m->object->ref_count != 0) {
1003 if (m->flags & PG_REFERENCED) {
1004 actcount += 1;
1005 }
1006 actcount += pmap_ts_referenced(m);
1007 if (actcount) {
1008 m->act_count += ACT_ADVANCE + actcount;
1009 if (m->act_count > ACT_MAX)
1010 m->act_count = ACT_MAX;
1011 }
1012 }
1013
1014 /*
1015 * Since we have "tested" this bit, we need to clear it now.
1016 */
1017 vm_page_flag_clear(m, PG_REFERENCED);
1018
1019 /*
1020 * Only if an object is currently being used, do we use the
1021 * page activation count stats.
1022 */
1023 if (actcount && (m->object->ref_count != 0)) {
1024 s = splvm();
1025 TAILQ_REMOVE(&vm_page_queues[PQ_ACTIVE].pl, m, pageq);
1026 TAILQ_INSERT_TAIL(&vm_page_queues[PQ_ACTIVE].pl, m, pageq);
1027 splx(s);
1028 } else {
1029 m->act_count -= min(m->act_count, ACT_DECLINE);
1030 if (vm_pageout_algorithm ||
1031 m->object->ref_count == 0 ||
1032 m->act_count == 0) {
1033 page_shortage--;
1034 if (m->object->ref_count == 0) {
1035 vm_page_protect(m, VM_PROT_NONE);
1036 if (m->dirty == 0)
1037 vm_page_cache(m);
1038 else
1039 vm_page_deactivate(m);
1040 } else {
1041 vm_page_deactivate(m);
1042 }
1043 } else {
1044 s = splvm();
1045 TAILQ_REMOVE(&vm_page_queues[PQ_ACTIVE].pl, m, pageq);
1046 TAILQ_INSERT_TAIL(&vm_page_queues[PQ_ACTIVE].pl, m, pageq);
1047 splx(s);
1048 }
1049 }
1050 m = next;
1051 }
1052
1053 s = splvm();
1054
1055 /*
1056 * We try to maintain some *really* free pages, this allows interrupt
1057 * code to be guaranteed space. Since both cache and free queues
1058 * are considered basically 'free', moving pages from cache to free
1059 * does not effect other calculations.
1060 */
1061
1062 while (cnt.v_free_count < cnt.v_free_reserved) {
1063 static int cache_rover = 0;
1064 m = vm_page_list_find(PQ_CACHE, cache_rover, FALSE);
1065 if (!m)
1066 break;
1067 if ((m->flags & (PG_BUSY|PG_UNMANAGED)) ||
1068 m->busy ||
1069 m->hold_count ||
1070 m->wire_count) {
1071#ifdef INVARIANTS
1072 printf("Warning: busy page %p found in cache\n", m);
1073#endif
1074 vm_page_deactivate(m);
1075 continue;
1076 }
1077 cache_rover = (cache_rover + PQ_PRIME2) & PQ_L2_MASK;
1078 vm_pageout_page_free(m);
1079 cnt.v_dfree++;
1080 }
1081 splx(s);
1082
1083#if !defined(NO_SWAPPING)
1084 /*
1085 * Idle process swapout -- run once per second.
1086 */
1087 if (vm_swap_idle_enabled) {
1088 static long lsec;
1089 if (time_second != lsec) {
1090 vm_pageout_req_swapout |= VM_SWAP_IDLE;
1091 vm_req_vmdaemon();
1092 lsec = time_second;
1093 }
1094 }
1095#endif
1096
1097 /*
1098 * If we didn't get enough free pages, and we have skipped a vnode
1099 * in a writeable object, wakeup the sync daemon. And kick swapout
1100 * if we did not get enough free pages.
1101 */
1102 if (vm_paging_target() > 0) {
1103 if (vnodes_skipped && vm_page_count_min())
1104 (void) speedup_syncer();
1105#if !defined(NO_SWAPPING)
1106 if (vm_swap_enabled && vm_page_count_target()) {
1107 vm_req_vmdaemon();
1108 vm_pageout_req_swapout |= VM_SWAP_NORMAL;
1109 }
1110#endif
1111 }
1112
1113 /*
1114 * If we are out of swap and were not able to reach our paging
1115 * target, kill the largest process.
1116 */
1117 if ((vm_swap_size < 64 && vm_page_count_min()) ||
1118 (swap_pager_full && vm_paging_target() > 0)) {
1119#if 0
1120 if ((vm_swap_size < 64 || swap_pager_full) && vm_page_count_min()) {
1121#endif
1122 bigproc = NULL;
1123 bigsize = 0;
1124 for (p = allproc.lh_first; p != 0; p = p->p_list.le_next) {
1125 /*
1126 * if this is a system process, skip it
1127 */
1128 if ((p->p_flag & P_SYSTEM) || (p->p_pid == 1) ||
1129 ((p->p_pid < 48) && (vm_swap_size != 0))) {
1130 continue;
1131 }
1132 /*
1133 * if the process is in a non-running type state,
1134 * don't touch it.
1135 */
1136 if (p->p_stat != SRUN && p->p_stat != SSLEEP) {
1137 continue;
1138 }
1139 /*
1140 * get the process size
1141 */
1142 size = vmspace_resident_count(p->p_vmspace) +
1143 vmspace_swap_count(p->p_vmspace);
1144 /*
1145 * if the this process is bigger than the biggest one
1146 * remember it.
1147 */
1148 if (size > bigsize) {
1149 bigproc = p;
1150 bigsize = size;
1151 }
1152 }
1153 if (bigproc != NULL) {
1154 killproc(bigproc, "out of swap space");
1155 bigproc->p_estcpu = 0;
1156 bigproc->p_nice = PRIO_MIN;
1157 resetpriority(bigproc);
1158 wakeup(&cnt.v_free_count);
1159 }
1160 }
1161}
1162
1163/*
1164 * This routine tries to maintain the pseudo LRU active queue,
1165 * so that during long periods of time where there is no paging,
1166 * that some statistic accumulation still occurs. This code
1167 * helps the situation where paging just starts to occur.
1168 */
1169static void
1170vm_pageout_page_stats()
1171{
1172 int s;
1173 vm_page_t m,next;
1174 int pcount,tpcount; /* Number of pages to check */
1175 static int fullintervalcount = 0;
1176 int page_shortage;
1177 int s0;
1178
1179 page_shortage =
1180 (cnt.v_inactive_target + cnt.v_cache_max + cnt.v_free_min) -
1181 (cnt.v_free_count + cnt.v_inactive_count + cnt.v_cache_count);
1182
1183 if (page_shortage <= 0)
1184 return;
1185
1186 s0 = splvm();
1187
1188 pcount = cnt.v_active_count;
1189 fullintervalcount += vm_pageout_stats_interval;
1190 if (fullintervalcount < vm_pageout_full_stats_interval) {
1191 tpcount = (vm_pageout_stats_max * cnt.v_active_count) / cnt.v_page_count;
1192 if (pcount > tpcount)
1193 pcount = tpcount;
1194 } else {
1195 fullintervalcount = 0;
1196 }
1197
1198 m = TAILQ_FIRST(&vm_page_queues[PQ_ACTIVE].pl);
1199 while ((m != NULL) && (pcount-- > 0)) {
1200 int actcount;
1201
1202 if (m->queue != PQ_ACTIVE) {
1203 break;
1204 }
1205
1206 next = TAILQ_NEXT(m, pageq);
1207 /*
1208 * Don't deactivate pages that are busy.
1209 */
1210 if ((m->busy != 0) ||
1211 (m->flags & PG_BUSY) ||
1212 (m->hold_count != 0)) {
1213 s = splvm();
1214 TAILQ_REMOVE(&vm_page_queues[PQ_ACTIVE].pl, m, pageq);
1215 TAILQ_INSERT_TAIL(&vm_page_queues[PQ_ACTIVE].pl, m, pageq);
1216 splx(s);
1217 m = next;
1218 continue;
1219 }
1220
1221 actcount = 0;
1222 if (m->flags & PG_REFERENCED) {
1223 vm_page_flag_clear(m, PG_REFERENCED);
1224 actcount += 1;
1225 }
1226
1227 actcount += pmap_ts_referenced(m);
1228 if (actcount) {
1229 m->act_count += ACT_ADVANCE + actcount;
1230 if (m->act_count > ACT_MAX)
1231 m->act_count = ACT_MAX;
1232 s = splvm();
1233 TAILQ_REMOVE(&vm_page_queues[PQ_ACTIVE].pl, m, pageq);
1234 TAILQ_INSERT_TAIL(&vm_page_queues[PQ_ACTIVE].pl, m, pageq);
1235 splx(s);
1236 } else {
1237 if (m->act_count == 0) {
1238 /*
1239 * We turn off page access, so that we have
1240 * more accurate RSS stats. We don't do this
1241 * in the normal page deactivation when the
1242 * system is loaded VM wise, because the
1243 * cost of the large number of page protect
1244 * operations would be higher than the value
1245 * of doing the operation.
1246 */
1247 vm_page_protect(m, VM_PROT_NONE);
1248 vm_page_deactivate(m);
1249 } else {
1250 m->act_count -= min(m->act_count, ACT_DECLINE);
1251 s = splvm();
1252 TAILQ_REMOVE(&vm_page_queues[PQ_ACTIVE].pl, m, pageq);
1253 TAILQ_INSERT_TAIL(&vm_page_queues[PQ_ACTIVE].pl, m, pageq);
1254 splx(s);
1255 }
1256 }
1257
1258 m = next;
1259 }
1260 splx(s0);
1261}
1262
1263static int
1264vm_pageout_free_page_calc(count)
1265vm_size_t count;
1266{
1267 if (count < cnt.v_page_count)
1268 return 0;
1269 /*
1270 * free_reserved needs to include enough for the largest swap pager
1271 * structures plus enough for any pv_entry structs when paging.
1272 */
1273 if (cnt.v_page_count > 1024)
1274 cnt.v_free_min = 4 + (cnt.v_page_count - 1024) / 200;
1275 else
1276 cnt.v_free_min = 4;
1277 cnt.v_pageout_free_min = (2*MAXBSIZE)/PAGE_SIZE +
1278 cnt.v_interrupt_free_min;
1279 cnt.v_free_reserved = vm_pageout_page_count +
1280 cnt.v_pageout_free_min + (count / 768) + PQ_L2_SIZE;
1281 cnt.v_free_severe = cnt.v_free_min / 2;
1282 cnt.v_free_min += cnt.v_free_reserved;
1283 cnt.v_free_severe += cnt.v_free_reserved;
1284 return 1;
1285}
1286
1287
1288/*
1289 * vm_pageout is the high level pageout daemon.
1290 */
1291static void
1292vm_pageout()
1293{
1294 int pass;
1295
1296 /*
1297 * Initialize some paging parameters.
1298 */
1299
1300 cnt.v_interrupt_free_min = 2;
1301 if (cnt.v_page_count < 2000)
1302 vm_pageout_page_count = 8;
1303
1304 vm_pageout_free_page_calc(cnt.v_page_count);
1305 /*
1306 * v_free_target and v_cache_min control pageout hysteresis. Note
1307 * that these are more a measure of the VM cache queue hysteresis
1308 * then the VM free queue. Specifically, v_free_target is the
1309 * high water mark (free+cache pages).
1310 *
1311 * v_free_reserved + v_cache_min (mostly means v_cache_min) is the
1312 * low water mark, while v_free_min is the stop. v_cache_min must
1313 * be big enough to handle memory needs while the pageout daemon
1314 * is signalled and run to free more pages.
1315 */
1316 if (cnt.v_free_count > 6144)
1317 cnt.v_free_target = 4 * cnt.v_free_min + cnt.v_free_reserved;
1318 else
1319 cnt.v_free_target = 2 * cnt.v_free_min + cnt.v_free_reserved;
1320
1321 if (cnt.v_free_count > 2048) {
1322 cnt.v_cache_min = cnt.v_free_target;
1323 cnt.v_cache_max = 2 * cnt.v_cache_min;
1324 cnt.v_inactive_target = (3 * cnt.v_free_target) / 2;
1325 } else {
1326 cnt.v_cache_min = 0;
1327 cnt.v_cache_max = 0;
1328 cnt.v_inactive_target = cnt.v_free_count / 4;
1329 }
1330 if (cnt.v_inactive_target > cnt.v_free_count / 3)
1331 cnt.v_inactive_target = cnt.v_free_count / 3;
1332
1333 /* XXX does not really belong here */
1334 if (vm_page_max_wired == 0)
1335 vm_page_max_wired = cnt.v_free_count / 3;
1336
1337 if (vm_pageout_stats_max == 0)
1338 vm_pageout_stats_max = cnt.v_free_target;
1339
1340 /*
1341 * Set interval in seconds for stats scan.
1342 */
1343 if (vm_pageout_stats_interval == 0)
1344 vm_pageout_stats_interval = 5;
1345 if (vm_pageout_full_stats_interval == 0)
1346 vm_pageout_full_stats_interval = vm_pageout_stats_interval * 4;
1347
1348
1349 /*
1350 * Set maximum free per pass
1351 */
1352 if (vm_pageout_stats_free_max == 0)
1353 vm_pageout_stats_free_max = 5;
1354
1355 swap_pager_swap_init();
1356 pass = 0;
1357 /*
1358 * The pageout daemon is never done, so loop forever.
1359 */
1360 while (TRUE) {
1361 int error;
1362 int s = splvm();
1363
1364 /*
1365 * If we have enough free memory, wakeup waiters. Do
1366 * not clear vm_pages_needed until we reach our target,
1367 * otherwise we may be woken up over and over again and
1368 * waste a lot of cpu.
1369 */
1370 if (vm_pages_needed && !vm_page_count_min()) {
1371 if (vm_paging_needed() <= 0)
1372 vm_pages_needed = 0;
1373 wakeup(&cnt.v_free_count);
1374 }
1375 if (vm_pages_needed) {
1376 /*
1377 * Still not done, take a second pass without waiting
1378 * (unlimited dirty cleaning), otherwise sleep a bit
1379 * and try again.
1380 */
1381 ++pass;
1382 if (pass > 1)
1383 tsleep(&vm_pages_needed, PVM, "psleep", hz/2);
1384 } else {
1385 /*
1386 * Good enough, sleep & handle stats. Prime the pass
1387 * for the next run.
1388 */
1389 if (pass > 1)
1390 pass = 1;
1391 else
1392 pass = 0;
1393 error = tsleep(&vm_pages_needed,
1394 PVM, "psleep", vm_pageout_stats_interval * hz);
1395 if (error && !vm_pages_needed) {
1396 splx(s);
1397 pass = 0;
1398 vm_pageout_page_stats();
1399 continue;
1400 }
1401 }
1402
1403 if (vm_pages_needed)
1404 cnt.v_pdwakeups++;
1405 splx(s);
1406 vm_pageout_scan(pass);
1407 vm_pageout_deficit = 0;
1408 }
1409}
1410
1411void
1412pagedaemon_wakeup()
1413{
bc6dffab 1414 if (!vm_pages_needed && curthread != pagethread) {
984263bc
MD
1415 vm_pages_needed++;
1416 wakeup(&vm_pages_needed);
1417 }
1418}
1419
1420#if !defined(NO_SWAPPING)
1421static void
1422vm_req_vmdaemon()
1423{
1424 static int lastrun = 0;
1425
1426 if ((ticks > (lastrun + hz)) || (ticks < lastrun)) {
1427 wakeup(&vm_daemon_needed);
1428 lastrun = ticks;
1429 }
1430}
1431
1432static void
1433vm_daemon()
1434{
1435 struct proc *p;
1436
1437 while (TRUE) {
1438 tsleep(&vm_daemon_needed, PPAUSE, "psleep", 0);
1439 if (vm_pageout_req_swapout) {
1440 swapout_procs(vm_pageout_req_swapout);
1441 vm_pageout_req_swapout = 0;
1442 }
1443 /*
1444 * scan the processes for exceeding their rlimits or if
1445 * process is swapped out -- deactivate pages
1446 */
1447
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 }
1487}
1488#endif