Remove DIAGNOSTIC elements that are no longer correct.
[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 $
57e43348 69 * $DragonFly: src/sys/vm/vm_pageout.c,v 1.10 2004/03/23 22:54:32 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>
12e4aaff 98#include <vm/vm_page2.h>
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99
100/*
101 * System initialization
102 */
103
104/* the kernel process "vm_pageout"*/
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105static void vm_pageout (void);
106static int vm_pageout_clean (vm_page_t);
107static void vm_pageout_scan (int pass);
108static int vm_pageout_free_page_calc (vm_size_t count);
bc6dffab 109struct thread *pagethread;
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110
111static struct kproc_desc page_kp = {
112 "pagedaemon",
113 vm_pageout,
bc6dffab 114 &pagethread
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115};
116SYSINIT(pagedaemon, SI_SUB_KTHREAD_PAGE, SI_ORDER_FIRST, kproc_start, &page_kp)
117
118#if !defined(NO_SWAPPING)
119/* the kernel process "vm_daemon"*/
1388df65 120static void vm_daemon (void);
bc6dffab 121static struct thread *vmthread;
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122
123static struct kproc_desc vm_kp = {
124 "vmdaemon",
125 vm_daemon,
bc6dffab 126 &vmthread
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127};
128SYSINIT(vmdaemon, SI_SUB_KTHREAD_VM, SI_ORDER_FIRST, kproc_start, &vm_kp)
129#endif
130
131
132int vm_pages_needed=0; /* Event on which pageout daemon sleeps */
133int vm_pageout_deficit=0; /* Estimated number of pages deficit */
134int vm_pageout_pages_needed=0; /* flag saying that the pageout daemon needs pages */
135
136#if !defined(NO_SWAPPING)
137static int vm_pageout_req_swapout; /* XXX */
138static int vm_daemon_needed;
139#endif
140extern int vm_swap_size;
141static int vm_max_launder = 32;
142static int vm_pageout_stats_max=0, vm_pageout_stats_interval = 0;
143static int vm_pageout_full_stats_interval = 0;
144static int vm_pageout_stats_free_max=0, vm_pageout_algorithm=0;
145static int defer_swap_pageouts=0;
146static int disable_swap_pageouts=0;
147
148#if defined(NO_SWAPPING)
149static int vm_swap_enabled=0;
150static int vm_swap_idle_enabled=0;
151#else
152static int vm_swap_enabled=1;
153static int vm_swap_idle_enabled=0;
154#endif
155
156SYSCTL_INT(_vm, VM_PAGEOUT_ALGORITHM, pageout_algorithm,
157 CTLFLAG_RW, &vm_pageout_algorithm, 0, "LRU page mgmt");
158
159SYSCTL_INT(_vm, OID_AUTO, max_launder,
160 CTLFLAG_RW, &vm_max_launder, 0, "Limit dirty flushes in pageout");
161
162SYSCTL_INT(_vm, OID_AUTO, pageout_stats_max,
163 CTLFLAG_RW, &vm_pageout_stats_max, 0, "Max pageout stats scan length");
164
165SYSCTL_INT(_vm, OID_AUTO, pageout_full_stats_interval,
166 CTLFLAG_RW, &vm_pageout_full_stats_interval, 0, "Interval for full stats scan");
167
168SYSCTL_INT(_vm, OID_AUTO, pageout_stats_interval,
169 CTLFLAG_RW, &vm_pageout_stats_interval, 0, "Interval for partial stats scan");
170
171SYSCTL_INT(_vm, OID_AUTO, pageout_stats_free_max,
172 CTLFLAG_RW, &vm_pageout_stats_free_max, 0, "Not implemented");
173
174#if defined(NO_SWAPPING)
175SYSCTL_INT(_vm, VM_SWAPPING_ENABLED, swap_enabled,
176 CTLFLAG_RD, &vm_swap_enabled, 0, "");
177SYSCTL_INT(_vm, OID_AUTO, swap_idle_enabled,
178 CTLFLAG_RD, &vm_swap_idle_enabled, 0, "");
179#else
180SYSCTL_INT(_vm, VM_SWAPPING_ENABLED, swap_enabled,
181 CTLFLAG_RW, &vm_swap_enabled, 0, "Enable entire process swapout");
182SYSCTL_INT(_vm, OID_AUTO, swap_idle_enabled,
183 CTLFLAG_RW, &vm_swap_idle_enabled, 0, "Allow swapout on idle criteria");
184#endif
185
186SYSCTL_INT(_vm, OID_AUTO, defer_swapspace_pageouts,
187 CTLFLAG_RW, &defer_swap_pageouts, 0, "Give preference to dirty pages in mem");
188
189SYSCTL_INT(_vm, OID_AUTO, disable_swapspace_pageouts,
190 CTLFLAG_RW, &disable_swap_pageouts, 0, "Disallow swapout of dirty pages");
191
192static int pageout_lock_miss;
193SYSCTL_INT(_vm, OID_AUTO, pageout_lock_miss,
194 CTLFLAG_RD, &pageout_lock_miss, 0, "vget() lock misses during pageout");
195
196#define VM_PAGEOUT_PAGE_COUNT 16
197int vm_pageout_page_count = VM_PAGEOUT_PAGE_COUNT;
198
199int vm_page_max_wired; /* XXX max # of wired pages system-wide */
200
201#if !defined(NO_SWAPPING)
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202typedef void freeer_fcn_t (vm_map_t, vm_object_t, vm_pindex_t, int);
203static void vm_pageout_map_deactivate_pages (vm_map_t, vm_pindex_t);
984263bc 204static freeer_fcn_t vm_pageout_object_deactivate_pages;
1388df65 205static void vm_req_vmdaemon (void);
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206#endif
207static void vm_pageout_page_stats(void);
208
209/*
210 * vm_pageout_clean:
211 *
212 * Clean the page and remove it from the laundry.
213 *
214 * We set the busy bit to cause potential page faults on this page to
215 * block. Note the careful timing, however, the busy bit isn't set till
216 * late and we cannot do anything that will mess with the page.
217 */
218
219static int
57e43348 220vm_pageout_clean(vm_page_t m)
984263bc 221{
5f910b2f 222 vm_object_t object;
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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
57e43348 357vm_pageout_flush(vm_page_t *mc, int count, int flags)
984263bc 358{
5f910b2f 359 vm_object_t object;
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360 int pageout_status[count];
361 int numpagedout = 0;
362 int i;
363
364 /*
365 * Initiate I/O. Bump the vm_page_t->busy counter and
366 * mark the pages read-only.
367 *
368 * We do not have to fixup the clean/dirty bits here... we can
369 * allow the pager to do it after the I/O completes.
370 */
371
372 for (i = 0; i < count; i++) {
373 KASSERT(mc[i]->valid == VM_PAGE_BITS_ALL, ("vm_pageout_flush page %p index %d/%d: partially invalid page", mc[i], i, count));
374 vm_page_io_start(mc[i]);
375 vm_page_protect(mc[i], VM_PROT_READ);
376 }
377
378 object = mc[0]->object;
379 vm_object_pip_add(object, count);
380
381 vm_pager_put_pages(object, mc, count,
382 (flags | ((object == kernel_object) ? VM_PAGER_PUT_SYNC : 0)),
383 pageout_status);
384
385 for (i = 0; i < count; i++) {
386 vm_page_t mt = mc[i];
387
388 switch (pageout_status[i]) {
389 case VM_PAGER_OK:
390 numpagedout++;
391 break;
392 case VM_PAGER_PEND:
393 numpagedout++;
394 break;
395 case VM_PAGER_BAD:
396 /*
397 * Page outside of range of object. Right now we
398 * essentially lose the changes by pretending it
399 * worked.
400 */
401 pmap_clear_modify(mt);
402 vm_page_undirty(mt);
403 break;
404 case VM_PAGER_ERROR:
405 case VM_PAGER_FAIL:
406 /*
407 * If page couldn't be paged out, then reactivate the
408 * page so it doesn't clog the inactive list. (We
409 * will try paging out it again later).
410 */
411 vm_page_activate(mt);
412 break;
413 case VM_PAGER_AGAIN:
414 break;
415 }
416
417 /*
418 * If the operation is still going, leave the page busy to
419 * block all other accesses. Also, leave the paging in
420 * progress indicator set so that we don't attempt an object
421 * collapse.
422 */
423 if (pageout_status[i] != VM_PAGER_PEND) {
424 vm_object_pip_wakeup(object);
425 vm_page_io_finish(mt);
426 if (!vm_page_count_severe() || !vm_page_try_to_cache(mt))
427 vm_page_protect(mt, VM_PROT_READ);
428 }
429 }
430 return numpagedout;
431}
432
433#if !defined(NO_SWAPPING)
434/*
435 * vm_pageout_object_deactivate_pages
436 *
437 * deactivate enough pages to satisfy the inactive target
438 * requirements or if vm_page_proc_limit is set, then
439 * deactivate all of the pages in the object and its
440 * backing_objects.
441 *
442 * The object and map must be locked.
443 */
444static void
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445vm_pageout_object_deactivate_pages(vm_map_t map, vm_object_t object,
446 vm_pindex_t desired, int map_remove_only)
984263bc 447{
5f910b2f 448 vm_page_t p, next;
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449 int rcount;
450 int remove_mode;
451 int s;
452
453 if (object->type == OBJT_DEVICE || object->type == OBJT_PHYS)
454 return;
455
456 while (object) {
457 if (pmap_resident_count(vm_map_pmap(map)) <= desired)
458 return;
459 if (object->paging_in_progress)
460 return;
461
462 remove_mode = map_remove_only;
463 if (object->shadow_count > 1)
464 remove_mode = 1;
465 /*
466 * scan the objects entire memory queue
467 */
468 rcount = object->resident_page_count;
469 p = TAILQ_FIRST(&object->memq);
470 while (p && (rcount-- > 0)) {
471 int actcount;
472 if (pmap_resident_count(vm_map_pmap(map)) <= desired)
473 return;
474 next = TAILQ_NEXT(p, listq);
12e4aaff 475 mycpu->gd_cnt.v_pdpages++;
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476 if (p->wire_count != 0 ||
477 p->hold_count != 0 ||
478 p->busy != 0 ||
479 (p->flags & (PG_BUSY|PG_UNMANAGED)) ||
480 !pmap_page_exists_quick(vm_map_pmap(map), p)) {
481 p = next;
482 continue;
483 }
484
485 actcount = pmap_ts_referenced(p);
486 if (actcount) {
487 vm_page_flag_set(p, PG_REFERENCED);
488 } else if (p->flags & PG_REFERENCED) {
489 actcount = 1;
490 }
491
492 if ((p->queue != PQ_ACTIVE) &&
493 (p->flags & PG_REFERENCED)) {
494 vm_page_activate(p);
495 p->act_count += actcount;
496 vm_page_flag_clear(p, PG_REFERENCED);
497 } else if (p->queue == PQ_ACTIVE) {
498 if ((p->flags & PG_REFERENCED) == 0) {
499 p->act_count -= min(p->act_count, ACT_DECLINE);
500 if (!remove_mode && (vm_pageout_algorithm || (p->act_count == 0))) {
501 vm_page_protect(p, VM_PROT_NONE);
502 vm_page_deactivate(p);
503 } else {
504 s = splvm();
505 TAILQ_REMOVE(&vm_page_queues[PQ_ACTIVE].pl, p, pageq);
506 TAILQ_INSERT_TAIL(&vm_page_queues[PQ_ACTIVE].pl, p, pageq);
507 splx(s);
508 }
509 } else {
510 vm_page_activate(p);
511 vm_page_flag_clear(p, PG_REFERENCED);
512 if (p->act_count < (ACT_MAX - ACT_ADVANCE))
513 p->act_count += ACT_ADVANCE;
514 s = splvm();
515 TAILQ_REMOVE(&vm_page_queues[PQ_ACTIVE].pl, p, pageq);
516 TAILQ_INSERT_TAIL(&vm_page_queues[PQ_ACTIVE].pl, p, pageq);
517 splx(s);
518 }
519 } else if (p->queue == PQ_INACTIVE) {
520 vm_page_protect(p, VM_PROT_NONE);
521 }
522 p = next;
523 }
524 object = object->backing_object;
525 }
526 return;
527}
528
529/*
530 * deactivate some number of pages in a map, try to do it fairly, but
531 * that is really hard to do.
532 */
533static void
57e43348 534vm_pageout_map_deactivate_pages(vm_map_t map, vm_pindex_t desired)
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535{
536 vm_map_entry_t tmpe;
537 vm_object_t obj, bigobj;
538 int nothingwired;
539
41a01a4d 540 if (lockmgr(&map->lock, LK_EXCLUSIVE | LK_NOWAIT, NULL, curthread)) {
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541 return;
542 }
543
544 bigobj = NULL;
545 nothingwired = TRUE;
546
547 /*
548 * first, search out the biggest object, and try to free pages from
549 * that.
550 */
551 tmpe = map->header.next;
552 while (tmpe != &map->header) {
553 if ((tmpe->eflags & MAP_ENTRY_IS_SUB_MAP) == 0) {
554 obj = tmpe->object.vm_object;
555 if ((obj != NULL) && (obj->shadow_count <= 1) &&
556 ((bigobj == NULL) ||
557 (bigobj->resident_page_count < obj->resident_page_count))) {
558 bigobj = obj;
559 }
560 }
561 if (tmpe->wired_count > 0)
562 nothingwired = FALSE;
563 tmpe = tmpe->next;
564 }
565
566 if (bigobj)
567 vm_pageout_object_deactivate_pages(map, bigobj, desired, 0);
568
569 /*
570 * Next, hunt around for other pages to deactivate. We actually
571 * do this search sort of wrong -- .text first is not the best idea.
572 */
573 tmpe = map->header.next;
574 while (tmpe != &map->header) {
575 if (pmap_resident_count(vm_map_pmap(map)) <= desired)
576 break;
577 if ((tmpe->eflags & MAP_ENTRY_IS_SUB_MAP) == 0) {
578 obj = tmpe->object.vm_object;
579 if (obj)
580 vm_pageout_object_deactivate_pages(map, obj, desired, 0);
581 }
582 tmpe = tmpe->next;
583 };
584
585 /*
586 * Remove all mappings if a process is swapped out, this will free page
587 * table pages.
588 */
589 if (desired == 0 && nothingwired)
590 pmap_remove(vm_map_pmap(map),
591 VM_MIN_ADDRESS, VM_MAXUSER_ADDRESS);
592 vm_map_unlock(map);
593 return;
594}
595#endif
596
597/*
598 * Don't try to be fancy - being fancy can lead to VOP_LOCK's and therefore
599 * to vnode deadlocks. We only do it for OBJT_DEFAULT and OBJT_SWAP objects
600 * which we know can be trivially freed.
601 */
602
603void
604vm_pageout_page_free(vm_page_t m) {
605 vm_object_t object = m->object;
606 int type = object->type;
607
608 if (type == OBJT_SWAP || type == OBJT_DEFAULT)
609 vm_object_reference(object);
610 vm_page_busy(m);
611 vm_page_protect(m, VM_PROT_NONE);
612 vm_page_free(m);
613 if (type == OBJT_SWAP || type == OBJT_DEFAULT)
614 vm_object_deallocate(object);
615}
616
617/*
618 * vm_pageout_scan does the dirty work for the pageout daemon.
619 */
620static void
621vm_pageout_scan(int pass)
622{
623 vm_page_t m, next;
624 struct vm_page marker;
625 int page_shortage, maxscan, pcount;
626 int addl_page_shortage, addl_page_shortage_init;
627 struct proc *p, *bigproc;
628 vm_offset_t size, bigsize;
629 vm_object_t object;
630 int actcount;
631 int vnodes_skipped = 0;
632 int maxlaunder;
633 int s;
634
635 /*
636 * Do whatever cleanup that the pmap code can.
637 */
638 pmap_collect();
639
640 addl_page_shortage_init = vm_pageout_deficit;
641 vm_pageout_deficit = 0;
642
643 /*
644 * Calculate the number of pages we want to either free or move
645 * to the cache.
646 */
647 page_shortage = vm_paging_target() + addl_page_shortage_init;
648
649 /*
650 * Initialize our marker
651 */
652 bzero(&marker, sizeof(marker));
653 marker.flags = PG_BUSY | PG_FICTITIOUS | PG_MARKER;
654 marker.queue = PQ_INACTIVE;
655 marker.wire_count = 1;
656
657 /*
658 * Start scanning the inactive queue for pages we can move to the
659 * cache or free. The scan will stop when the target is reached or
660 * we have scanned the entire inactive queue. Note that m->act_count
661 * is not used to form decisions for the inactive queue, only for the
662 * active queue.
663 *
664 * maxlaunder limits the number of dirty pages we flush per scan.
665 * For most systems a smaller value (16 or 32) is more robust under
666 * extreme memory and disk pressure because any unnecessary writes
667 * to disk can result in extreme performance degredation. However,
668 * systems with excessive dirty pages (especially when MAP_NOSYNC is
669 * used) will die horribly with limited laundering. If the pageout
670 * daemon cannot clean enough pages in the first pass, we let it go
671 * all out in succeeding passes.
672 */
673 if ((maxlaunder = vm_max_launder) <= 1)
674 maxlaunder = 1;
675 if (pass)
676 maxlaunder = 10000;
677
678rescan0:
679 addl_page_shortage = addl_page_shortage_init;
12e4aaff 680 maxscan = vmstats.v_inactive_count;
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681 for (m = TAILQ_FIRST(&vm_page_queues[PQ_INACTIVE].pl);
682 m != NULL && maxscan-- > 0 && page_shortage > 0;
683 m = next) {
684
12e4aaff 685 mycpu->gd_cnt.v_pdpages++;
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686
687 if (m->queue != PQ_INACTIVE) {
688 goto rescan0;
689 }
690
691 next = TAILQ_NEXT(m, pageq);
692
693 /*
694 * skip marker pages
695 */
696 if (m->flags & PG_MARKER)
697 continue;
698
699 /*
700 * A held page may be undergoing I/O, so skip it.
701 */
702 if (m->hold_count) {
703 s = splvm();
704 TAILQ_REMOVE(&vm_page_queues[PQ_INACTIVE].pl, m, pageq);
705 TAILQ_INSERT_TAIL(&vm_page_queues[PQ_INACTIVE].pl, m, pageq);
706 splx(s);
707 addl_page_shortage++;
708 continue;
709 }
710 /*
711 * Dont mess with busy pages, keep in the front of the
712 * queue, most likely are being paged out.
713 */
714 if (m->busy || (m->flags & PG_BUSY)) {
715 addl_page_shortage++;
716 continue;
717 }
718
719 /*
720 * If the object is not being used, we ignore previous
721 * references.
722 */
723 if (m->object->ref_count == 0) {
724 vm_page_flag_clear(m, PG_REFERENCED);
725 pmap_clear_reference(m);
726
727 /*
728 * Otherwise, if the page has been referenced while in the
729 * inactive queue, we bump the "activation count" upwards,
730 * making it less likely that the page will be added back to
731 * the inactive queue prematurely again. Here we check the
732 * page tables (or emulated bits, if any), given the upper
733 * level VM system not knowing anything about existing
734 * references.
735 */
736 } else if (((m->flags & PG_REFERENCED) == 0) &&
737 (actcount = pmap_ts_referenced(m))) {
738 vm_page_activate(m);
739 m->act_count += (actcount + ACT_ADVANCE);
740 continue;
741 }
742
743 /*
744 * If the upper level VM system knows about any page
745 * references, we activate the page. We also set the
746 * "activation count" higher than normal so that we will less
747 * likely place pages back onto the inactive queue again.
748 */
749 if ((m->flags & PG_REFERENCED) != 0) {
750 vm_page_flag_clear(m, PG_REFERENCED);
751 actcount = pmap_ts_referenced(m);
752 vm_page_activate(m);
753 m->act_count += (actcount + ACT_ADVANCE + 1);
754 continue;
755 }
756
757 /*
758 * If the upper level VM system doesn't know anything about
759 * the page being dirty, we have to check for it again. As
760 * far as the VM code knows, any partially dirty pages are
761 * fully dirty.
41a01a4d
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762 *
763 * Pages marked PG_WRITEABLE may be mapped into the user
764 * address space of a process running on another cpu. A
765 * user process (without holding the MP lock) running on
766 * another cpu may be able to touch the page while we are
767 * trying to remove it. To prevent this from occuring we
768 * must call pmap_remove_all() or otherwise make the page
769 * read-only. If the race occured pmap_remove_all() is
770 * responsible for setting m->dirty.
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771 */
772 if (m->dirty == 0) {
773 vm_page_test_dirty(m);
41a01a4d
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774#if 0
775 if (m->dirty == 0 && (m->flags & PG_WRITEABLE) != 0)
776 pmap_remove_all(m);
777#endif
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778 } else {
779 vm_page_dirty(m);
780 }
781
984263bc 782 if (m->valid == 0) {
41a01a4d
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783 /*
784 * Invalid pages can be easily freed
785 */
984263bc 786 vm_pageout_page_free(m);
12e4aaff 787 mycpu->gd_cnt.v_dfree++;
984263bc 788 --page_shortage;
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789 } else if (m->dirty == 0) {
790 /*
41a01a4d
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791 * Clean pages can be placed onto the cache queue.
792 * This effectively frees them.
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793 */
794 vm_page_cache(m);
795 --page_shortage;
796 } else if ((m->flags & PG_WINATCFLS) == 0 && pass == 0) {
797 /*
798 * Dirty pages need to be paged out, but flushing
799 * a page is extremely expensive verses freeing
800 * a clean page. Rather then artificially limiting
801 * the number of pages we can flush, we instead give
802 * dirty pages extra priority on the inactive queue
803 * by forcing them to be cycled through the queue
804 * twice before being flushed, after which the
805 * (now clean) page will cycle through once more
806 * before being freed. This significantly extends
807 * the thrash point for a heavily loaded machine.
808 */
809 s = splvm();
810 vm_page_flag_set(m, PG_WINATCFLS);
811 TAILQ_REMOVE(&vm_page_queues[PQ_INACTIVE].pl, m, pageq);
812 TAILQ_INSERT_TAIL(&vm_page_queues[PQ_INACTIVE].pl, m, pageq);
813 splx(s);
814 } else if (maxlaunder > 0) {
815 /*
816 * We always want to try to flush some dirty pages if
817 * we encounter them, to keep the system stable.
818 * Normally this number is small, but under extreme
819 * pressure where there are insufficient clean pages
820 * on the inactive queue, we may have to go all out.
821 */
822 int swap_pageouts_ok;
823 struct vnode *vp = NULL;
824
825 object = m->object;
826
827 if ((object->type != OBJT_SWAP) && (object->type != OBJT_DEFAULT)) {
828 swap_pageouts_ok = 1;
829 } else {
830 swap_pageouts_ok = !(defer_swap_pageouts || disable_swap_pageouts);
831 swap_pageouts_ok |= (!disable_swap_pageouts && defer_swap_pageouts &&
832 vm_page_count_min());
833
834 }
835
836 /*
837 * We don't bother paging objects that are "dead".
838 * Those objects are in a "rundown" state.
839 */
840 if (!swap_pageouts_ok || (object->flags & OBJ_DEAD)) {
841 s = splvm();
842 TAILQ_REMOVE(&vm_page_queues[PQ_INACTIVE].pl, m, pageq);
843 TAILQ_INSERT_TAIL(&vm_page_queues[PQ_INACTIVE].pl, m, pageq);
844 splx(s);
845 continue;
846 }
847
848 /*
849 * The object is already known NOT to be dead. It
850 * is possible for the vget() to block the whole
851 * pageout daemon, but the new low-memory handling
852 * code should prevent it.
853 *
854 * The previous code skipped locked vnodes and, worse,
855 * reordered pages in the queue. This results in
856 * completely non-deterministic operation because,
857 * quite often, a vm_fault has initiated an I/O and
858 * is holding a locked vnode at just the point where
859 * the pageout daemon is woken up.
860 *
861 * We can't wait forever for the vnode lock, we might
862 * deadlock due to a vn_read() getting stuck in
863 * vm_wait while holding this vnode. We skip the
864 * vnode if we can't get it in a reasonable amount
865 * of time.
866 */
867
868 if (object->type == OBJT_VNODE) {
869 vp = object->handle;
870
41a01a4d 871 if (vget(vp, NULL, LK_EXCLUSIVE|LK_NOOBJ|LK_TIMELOCK, curthread)) {
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872 ++pageout_lock_miss;
873 if (object->flags & OBJ_MIGHTBEDIRTY)
874 vnodes_skipped++;
875 continue;
876 }
877
878 /*
879 * The page might have been moved to another
880 * queue during potential blocking in vget()
881 * above. The page might have been freed and
882 * reused for another vnode. The object might
883 * have been reused for another vnode.
884 */
885 if (m->queue != PQ_INACTIVE ||
886 m->object != object ||
887 object->handle != vp) {
888 if (object->flags & OBJ_MIGHTBEDIRTY)
889 vnodes_skipped++;
890 vput(vp);
891 continue;
892 }
893
894 /*
895 * The page may have been busied during the
896 * blocking in vput(); We don't move the
897 * page back onto the end of the queue so that
898 * statistics are more correct if we don't.
899 */
900 if (m->busy || (m->flags & PG_BUSY)) {
901 vput(vp);
902 continue;
903 }
904
905 /*
906 * If the page has become held it might
907 * be undergoing I/O, so skip it
908 */
909 if (m->hold_count) {
910 s = splvm();
911 TAILQ_REMOVE(&vm_page_queues[PQ_INACTIVE].pl, m, pageq);
912 TAILQ_INSERT_TAIL(&vm_page_queues[PQ_INACTIVE].pl, m, pageq);
913 splx(s);
914 if (object->flags & OBJ_MIGHTBEDIRTY)
915 vnodes_skipped++;
916 vput(vp);
917 continue;
918 }
919 }
920
921 /*
922 * If a page is dirty, then it is either being washed
923 * (but not yet cleaned) or it is still in the
924 * laundry. If it is still in the laundry, then we
925 * start the cleaning operation.
926 *
927 * This operation may cluster, invalidating the 'next'
928 * pointer. To prevent an inordinate number of
929 * restarts we use our marker to remember our place.
930 *
931 * decrement page_shortage on success to account for
932 * the (future) cleaned page. Otherwise we could wind
933 * up laundering or cleaning too many pages.
934 */
935 s = splvm();
936 TAILQ_INSERT_AFTER(&vm_page_queues[PQ_INACTIVE].pl, m, &marker, pageq);
937 splx(s);
938 if (vm_pageout_clean(m) != 0) {
939 --page_shortage;
940 --maxlaunder;
941 }
942 s = splvm();
943 next = TAILQ_NEXT(&marker, pageq);
944 TAILQ_REMOVE(&vm_page_queues[PQ_INACTIVE].pl, &marker, pageq);
945 splx(s);
946 if (vp != NULL)
947 vput(vp);
948 }
949 }
950
951 /*
952 * Compute the number of pages we want to try to move from the
953 * active queue to the inactive queue.
954 */
955 page_shortage = vm_paging_target() +
12e4aaff 956 vmstats.v_inactive_target - vmstats.v_inactive_count;
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957 page_shortage += addl_page_shortage;
958
959 /*
960 * Scan the active queue for things we can deactivate. We nominally
961 * track the per-page activity counter and use it to locate
962 * deactivation candidates.
963 */
964
12e4aaff 965 pcount = vmstats.v_active_count;
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966 m = TAILQ_FIRST(&vm_page_queues[PQ_ACTIVE].pl);
967
968 while ((m != NULL) && (pcount-- > 0) && (page_shortage > 0)) {
969
970 /*
971 * This is a consistency check, and should likely be a panic
972 * or warning.
973 */
974 if (m->queue != PQ_ACTIVE) {
975 break;
976 }
977
978 next = TAILQ_NEXT(m, pageq);
979 /*
980 * Don't deactivate pages that are busy.
981 */
982 if ((m->busy != 0) ||
983 (m->flags & PG_BUSY) ||
984 (m->hold_count != 0)) {
985 s = splvm();
986 TAILQ_REMOVE(&vm_page_queues[PQ_ACTIVE].pl, m, pageq);
987 TAILQ_INSERT_TAIL(&vm_page_queues[PQ_ACTIVE].pl, m, pageq);
988 splx(s);
989 m = next;
990 continue;
991 }
992
993 /*
994 * The count for pagedaemon pages is done after checking the
995 * page for eligibility...
996 */
12e4aaff 997 mycpu->gd_cnt.v_pdpages++;
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998
999 /*
1000 * Check to see "how much" the page has been used.
1001 */
1002 actcount = 0;
1003 if (m->object->ref_count != 0) {
1004 if (m->flags & PG_REFERENCED) {
1005 actcount += 1;
1006 }
1007 actcount += pmap_ts_referenced(m);
1008 if (actcount) {
1009 m->act_count += ACT_ADVANCE + actcount;
1010 if (m->act_count > ACT_MAX)
1011 m->act_count = ACT_MAX;
1012 }
1013 }
1014
1015 /*
1016 * Since we have "tested" this bit, we need to clear it now.
1017 */
1018 vm_page_flag_clear(m, PG_REFERENCED);
1019
1020 /*
1021 * Only if an object is currently being used, do we use the
1022 * page activation count stats.
1023 */
1024 if (actcount && (m->object->ref_count != 0)) {
1025 s = splvm();
1026 TAILQ_REMOVE(&vm_page_queues[PQ_ACTIVE].pl, m, pageq);
1027 TAILQ_INSERT_TAIL(&vm_page_queues[PQ_ACTIVE].pl, m, pageq);
1028 splx(s);
1029 } else {
1030 m->act_count -= min(m->act_count, ACT_DECLINE);
1031 if (vm_pageout_algorithm ||
1032 m->object->ref_count == 0 ||
1033 m->act_count == 0) {
1034 page_shortage--;
1035 if (m->object->ref_count == 0) {
1036 vm_page_protect(m, VM_PROT_NONE);
1037 if (m->dirty == 0)
1038 vm_page_cache(m);
1039 else
1040 vm_page_deactivate(m);
1041 } else {
1042 vm_page_deactivate(m);
1043 }
1044 } else {
1045 s = splvm();
1046 TAILQ_REMOVE(&vm_page_queues[PQ_ACTIVE].pl, m, pageq);
1047 TAILQ_INSERT_TAIL(&vm_page_queues[PQ_ACTIVE].pl, m, pageq);
1048 splx(s);
1049 }
1050 }
1051 m = next;
1052 }
1053
1054 s = splvm();
1055
1056 /*
1057 * We try to maintain some *really* free pages, this allows interrupt
1058 * code to be guaranteed space. Since both cache and free queues
1059 * are considered basically 'free', moving pages from cache to free
1060 * does not effect other calculations.
1061 */
1062
12e4aaff 1063 while (vmstats.v_free_count < vmstats.v_free_reserved) {
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1064 static int cache_rover = 0;
1065 m = vm_page_list_find(PQ_CACHE, cache_rover, FALSE);
1066 if (!m)
1067 break;
1068 if ((m->flags & (PG_BUSY|PG_UNMANAGED)) ||
1069 m->busy ||
1070 m->hold_count ||
1071 m->wire_count) {
1072#ifdef INVARIANTS
1073 printf("Warning: busy page %p found in cache\n", m);
1074#endif
1075 vm_page_deactivate(m);
1076 continue;
1077 }
1078 cache_rover = (cache_rover + PQ_PRIME2) & PQ_L2_MASK;
1079 vm_pageout_page_free(m);
12e4aaff 1080 mycpu->gd_cnt.v_dfree++;
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MD
1081 }
1082 splx(s);
1083
1084#if !defined(NO_SWAPPING)
1085 /*
1086 * Idle process swapout -- run once per second.
1087 */
1088 if (vm_swap_idle_enabled) {
1089 static long lsec;
1090 if (time_second != lsec) {
1091 vm_pageout_req_swapout |= VM_SWAP_IDLE;
1092 vm_req_vmdaemon();
1093 lsec = time_second;
1094 }
1095 }
1096#endif
1097
1098 /*
1099 * If we didn't get enough free pages, and we have skipped a vnode
1100 * in a writeable object, wakeup the sync daemon. And kick swapout
1101 * if we did not get enough free pages.
1102 */
1103 if (vm_paging_target() > 0) {
1104 if (vnodes_skipped && vm_page_count_min())
1105 (void) speedup_syncer();
1106#if !defined(NO_SWAPPING)
1107 if (vm_swap_enabled && vm_page_count_target()) {
1108 vm_req_vmdaemon();
1109 vm_pageout_req_swapout |= VM_SWAP_NORMAL;
1110 }
1111#endif
1112 }
1113
1114 /*
1115 * If we are out of swap and were not able to reach our paging
1116 * target, kill the largest process.
1117 */
1118 if ((vm_swap_size < 64 && vm_page_count_min()) ||
1119 (swap_pager_full && vm_paging_target() > 0)) {
1120#if 0
1121 if ((vm_swap_size < 64 || swap_pager_full) && vm_page_count_min()) {
1122#endif
1123 bigproc = NULL;
1124 bigsize = 0;
1125 for (p = allproc.lh_first; p != 0; p = p->p_list.le_next) {
1126 /*
1127 * if this is a system process, skip it
1128 */
1129 if ((p->p_flag & P_SYSTEM) || (p->p_pid == 1) ||
1130 ((p->p_pid < 48) && (vm_swap_size != 0))) {
1131 continue;
1132 }
1133 /*
1134 * if the process is in a non-running type state,
1135 * don't touch it.
1136 */
1137 if (p->p_stat != SRUN && p->p_stat != SSLEEP) {
1138 continue;
1139 }
1140 /*
1141 * get the process size
1142 */
1143 size = vmspace_resident_count(p->p_vmspace) +
1144 vmspace_swap_count(p->p_vmspace);
1145 /*
1146 * if the this process is bigger than the biggest one
1147 * remember it.
1148 */
1149 if (size > bigsize) {
1150 bigproc = p;
1151 bigsize = size;
1152 }
1153 }
1154 if (bigproc != NULL) {
1155 killproc(bigproc, "out of swap space");
1156 bigproc->p_estcpu = 0;
1157 bigproc->p_nice = PRIO_MIN;
1158 resetpriority(bigproc);
12e4aaff 1159 wakeup(&vmstats.v_free_count);
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1160 }
1161 }
1162}
1163
1164/*
1165 * This routine tries to maintain the pseudo LRU active queue,
1166 * so that during long periods of time where there is no paging,
1167 * that some statistic accumulation still occurs. This code
1168 * helps the situation where paging just starts to occur.
1169 */
1170static void
57e43348 1171vm_pageout_page_stats(void)
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MD
1172{
1173 int s;
1174 vm_page_t m,next;
1175 int pcount,tpcount; /* Number of pages to check */
1176 static int fullintervalcount = 0;
1177 int page_shortage;
1178 int s0;
1179
1180 page_shortage =
12e4aaff
MD
1181 (vmstats.v_inactive_target + vmstats.v_cache_max + vmstats.v_free_min) -
1182 (vmstats.v_free_count + vmstats.v_inactive_count + vmstats.v_cache_count);
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MD
1183
1184 if (page_shortage <= 0)
1185 return;
1186
1187 s0 = splvm();
1188
12e4aaff 1189 pcount = vmstats.v_active_count;
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1190 fullintervalcount += vm_pageout_stats_interval;
1191 if (fullintervalcount < vm_pageout_full_stats_interval) {
12e4aaff 1192 tpcount = (vm_pageout_stats_max * vmstats.v_active_count) / vmstats.v_page_count;
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1193 if (pcount > tpcount)
1194 pcount = tpcount;
1195 } else {
1196 fullintervalcount = 0;
1197 }
1198
1199 m = TAILQ_FIRST(&vm_page_queues[PQ_ACTIVE].pl);
1200 while ((m != NULL) && (pcount-- > 0)) {
1201 int actcount;
1202
1203 if (m->queue != PQ_ACTIVE) {
1204 break;
1205 }
1206
1207 next = TAILQ_NEXT(m, pageq);
1208 /*
1209 * Don't deactivate pages that are busy.
1210 */
1211 if ((m->busy != 0) ||
1212 (m->flags & PG_BUSY) ||
1213 (m->hold_count != 0)) {
1214 s = splvm();
1215 TAILQ_REMOVE(&vm_page_queues[PQ_ACTIVE].pl, m, pageq);
1216 TAILQ_INSERT_TAIL(&vm_page_queues[PQ_ACTIVE].pl, m, pageq);
1217 splx(s);
1218 m = next;
1219 continue;
1220 }
1221
1222 actcount = 0;
1223 if (m->flags & PG_REFERENCED) {
1224 vm_page_flag_clear(m, PG_REFERENCED);
1225 actcount += 1;
1226 }
1227
1228 actcount += pmap_ts_referenced(m);
1229 if (actcount) {
1230 m->act_count += ACT_ADVANCE + actcount;
1231 if (m->act_count > ACT_MAX)
1232 m->act_count = ACT_MAX;
1233 s = splvm();
1234 TAILQ_REMOVE(&vm_page_queues[PQ_ACTIVE].pl, m, pageq);
1235 TAILQ_INSERT_TAIL(&vm_page_queues[PQ_ACTIVE].pl, m, pageq);
1236 splx(s);
1237 } else {
1238 if (m->act_count == 0) {
1239 /*
1240 * We turn off page access, so that we have
1241 * more accurate RSS stats. We don't do this
1242 * in the normal page deactivation when the
1243 * system is loaded VM wise, because the
1244 * cost of the large number of page protect
1245 * operations would be higher than the value
1246 * of doing the operation.
1247 */
1248 vm_page_protect(m, VM_PROT_NONE);
1249 vm_page_deactivate(m);
1250 } else {
1251 m->act_count -= min(m->act_count, ACT_DECLINE);
1252 s = splvm();
1253 TAILQ_REMOVE(&vm_page_queues[PQ_ACTIVE].pl, m, pageq);
1254 TAILQ_INSERT_TAIL(&vm_page_queues[PQ_ACTIVE].pl, m, pageq);
1255 splx(s);
1256 }
1257 }
1258
1259 m = next;
1260 }
1261 splx(s0);
1262}
1263
1264static int
57e43348 1265vm_pageout_free_page_calc(vm_size_t count)
984263bc 1266{
12e4aaff 1267 if (count < vmstats.v_page_count)
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MD
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 */
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MD
1273 if (vmstats.v_page_count > 1024)
1274 vmstats.v_free_min = 4 + (vmstats.v_page_count - 1024) / 200;
984263bc 1275 else
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MD
1276 vmstats.v_free_min = 4;
1277 vmstats.v_pageout_free_min = (2*MAXBSIZE)/PAGE_SIZE +
1278 vmstats.v_interrupt_free_min;
1279 vmstats.v_free_reserved = vm_pageout_page_count +
1280 vmstats.v_pageout_free_min + (count / 768) + PQ_L2_SIZE;
1281 vmstats.v_free_severe = vmstats.v_free_min / 2;
1282 vmstats.v_free_min += vmstats.v_free_reserved;
1283 vmstats.v_free_severe += vmstats.v_free_reserved;
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1284 return 1;
1285}
1286
1287
1288/*
1289 * vm_pageout is the high level pageout daemon.
1290 */
1291static void
57e43348 1292vm_pageout(void)
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1293{
1294 int pass;
1295
1296 /*
1297 * Initialize some paging parameters.
1298 */
1299
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1300 vmstats.v_interrupt_free_min = 2;
1301 if (vmstats.v_page_count < 2000)
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1302 vm_pageout_page_count = 8;
1303
12e4aaff 1304 vm_pageout_free_page_calc(vmstats.v_page_count);
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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 */
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1316 if (vmstats.v_free_count > 6144)
1317 vmstats.v_free_target = 4 * vmstats.v_free_min + vmstats.v_free_reserved;
984263bc 1318 else
12e4aaff 1319 vmstats.v_free_target = 2 * vmstats.v_free_min + vmstats.v_free_reserved;
984263bc 1320
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1321 if (vmstats.v_free_count > 2048) {
1322 vmstats.v_cache_min = vmstats.v_free_target;
1323 vmstats.v_cache_max = 2 * vmstats.v_cache_min;
1324 vmstats.v_inactive_target = (3 * vmstats.v_free_target) / 2;
984263bc 1325 } else {
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1326 vmstats.v_cache_min = 0;
1327 vmstats.v_cache_max = 0;
1328 vmstats.v_inactive_target = vmstats.v_free_count / 4;
984263bc 1329 }
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1330 if (vmstats.v_inactive_target > vmstats.v_free_count / 3)
1331 vmstats.v_inactive_target = vmstats.v_free_count / 3;
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1332
1333 /* XXX does not really belong here */
1334 if (vm_page_max_wired == 0)
12e4aaff 1335 vm_page_max_wired = vmstats.v_free_count / 3;
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1336
1337 if (vm_pageout_stats_max == 0)
12e4aaff 1338 vm_pageout_stats_max = vmstats.v_free_target;
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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;
12e4aaff 1373 wakeup(&vmstats.v_free_count);
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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)
377d4740 1383 tsleep(&vm_pages_needed, 0, "psleep", hz/2);
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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,
377d4740 1394 0, "psleep", vm_pageout_stats_interval * hz);
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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)
12e4aaff 1404 mycpu->gd_cnt.v_pdwakeups++;
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1405 splx(s);
1406 vm_pageout_scan(pass);
1407 vm_pageout_deficit = 0;
1408 }
1409}
1410
1411void
57e43348 1412pagedaemon_wakeup(void)
984263bc 1413{
bc6dffab 1414 if (!vm_pages_needed && curthread != pagethread) {
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1415 vm_pages_needed++;
1416 wakeup(&vm_pages_needed);
1417 }
1418}
1419
1420#if !defined(NO_SWAPPING)
1421static void
57e43348 1422vm_req_vmdaemon(void)
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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
57e43348 1433vm_daemon(void)
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1434{
1435 struct proc *p;
1436
1437 while (TRUE) {
377d4740 1438 tsleep(&vm_daemon_needed, 0, "psleep", 0);
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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