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[dragonfly.git] / sys / vm / vm_pageout.c
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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 $
a11aaa81 69 * $DragonFly: src/sys/vm/vm_pageout.c,v 1.24 2006/08/12 00:26:22 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>
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98
99#include <sys/thread2.h>
12e4aaff 100#include <vm/vm_page2.h>
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101
102/*
103 * System initialization
104 */
105
106/* the kernel process "vm_pageout"*/
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107static void vm_pageout (void);
108static int vm_pageout_clean (vm_page_t);
109static void vm_pageout_scan (int pass);
110static int vm_pageout_free_page_calc (vm_size_t count);
bc6dffab 111struct thread *pagethread;
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112
113static struct kproc_desc page_kp = {
114 "pagedaemon",
115 vm_pageout,
bc6dffab 116 &pagethread
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117};
118SYSINIT(pagedaemon, SI_SUB_KTHREAD_PAGE, SI_ORDER_FIRST, kproc_start, &page_kp)
119
120#if !defined(NO_SWAPPING)
121/* the kernel process "vm_daemon"*/
1388df65 122static void vm_daemon (void);
bc6dffab 123static struct thread *vmthread;
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124
125static struct kproc_desc vm_kp = {
126 "vmdaemon",
127 vm_daemon,
bc6dffab 128 &vmthread
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129};
130SYSINIT(vmdaemon, SI_SUB_KTHREAD_VM, SI_ORDER_FIRST, kproc_start, &vm_kp)
131#endif
132
133
134int vm_pages_needed=0; /* Event on which pageout daemon sleeps */
135int vm_pageout_deficit=0; /* Estimated number of pages deficit */
136int vm_pageout_pages_needed=0; /* flag saying that the pageout daemon needs pages */
137
138#if !defined(NO_SWAPPING)
139static int vm_pageout_req_swapout; /* XXX */
140static int vm_daemon_needed;
141#endif
142extern int vm_swap_size;
143static int vm_max_launder = 32;
144static int vm_pageout_stats_max=0, vm_pageout_stats_interval = 0;
145static int vm_pageout_full_stats_interval = 0;
146static int vm_pageout_stats_free_max=0, vm_pageout_algorithm=0;
147static int defer_swap_pageouts=0;
148static int disable_swap_pageouts=0;
149
150#if defined(NO_SWAPPING)
151static int vm_swap_enabled=0;
152static int vm_swap_idle_enabled=0;
153#else
154static int vm_swap_enabled=1;
155static int vm_swap_idle_enabled=0;
156#endif
157
158SYSCTL_INT(_vm, VM_PAGEOUT_ALGORITHM, pageout_algorithm,
159 CTLFLAG_RW, &vm_pageout_algorithm, 0, "LRU page mgmt");
160
161SYSCTL_INT(_vm, OID_AUTO, max_launder,
162 CTLFLAG_RW, &vm_max_launder, 0, "Limit dirty flushes in pageout");
163
164SYSCTL_INT(_vm, OID_AUTO, pageout_stats_max,
165 CTLFLAG_RW, &vm_pageout_stats_max, 0, "Max pageout stats scan length");
166
167SYSCTL_INT(_vm, OID_AUTO, pageout_full_stats_interval,
168 CTLFLAG_RW, &vm_pageout_full_stats_interval, 0, "Interval for full stats scan");
169
170SYSCTL_INT(_vm, OID_AUTO, pageout_stats_interval,
171 CTLFLAG_RW, &vm_pageout_stats_interval, 0, "Interval for partial stats scan");
172
173SYSCTL_INT(_vm, OID_AUTO, pageout_stats_free_max,
174 CTLFLAG_RW, &vm_pageout_stats_free_max, 0, "Not implemented");
175
176#if defined(NO_SWAPPING)
177SYSCTL_INT(_vm, VM_SWAPPING_ENABLED, swap_enabled,
178 CTLFLAG_RD, &vm_swap_enabled, 0, "");
179SYSCTL_INT(_vm, OID_AUTO, swap_idle_enabled,
180 CTLFLAG_RD, &vm_swap_idle_enabled, 0, "");
181#else
182SYSCTL_INT(_vm, VM_SWAPPING_ENABLED, swap_enabled,
183 CTLFLAG_RW, &vm_swap_enabled, 0, "Enable entire process swapout");
184SYSCTL_INT(_vm, OID_AUTO, swap_idle_enabled,
185 CTLFLAG_RW, &vm_swap_idle_enabled, 0, "Allow swapout on idle criteria");
186#endif
187
188SYSCTL_INT(_vm, OID_AUTO, defer_swapspace_pageouts,
189 CTLFLAG_RW, &defer_swap_pageouts, 0, "Give preference to dirty pages in mem");
190
191SYSCTL_INT(_vm, OID_AUTO, disable_swapspace_pageouts,
192 CTLFLAG_RW, &disable_swap_pageouts, 0, "Disallow swapout of dirty pages");
193
194static int pageout_lock_miss;
195SYSCTL_INT(_vm, OID_AUTO, pageout_lock_miss,
196 CTLFLAG_RD, &pageout_lock_miss, 0, "vget() lock misses during pageout");
197
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198int vm_load;
199SYSCTL_INT(_vm, OID_AUTO, vm_load,
200 CTLFLAG_RD, &vm_load, 0, "load on the VM system");
201int vm_load_enable = 1;
202SYSCTL_INT(_vm, OID_AUTO, vm_load_enable,
203 CTLFLAG_RW, &vm_load_enable, 0, "enable vm_load rate limiting");
204#ifdef INVARIANTS
205int vm_load_debug;
206SYSCTL_INT(_vm, OID_AUTO, vm_load_debug,
207 CTLFLAG_RW, &vm_load_debug, 0, "debug vm_load");
208#endif
209
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210#define VM_PAGEOUT_PAGE_COUNT 16
211int vm_pageout_page_count = VM_PAGEOUT_PAGE_COUNT;
212
213int vm_page_max_wired; /* XXX max # of wired pages system-wide */
214
215#if !defined(NO_SWAPPING)
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216typedef void freeer_fcn_t (vm_map_t, vm_object_t, vm_pindex_t, int);
217static void vm_pageout_map_deactivate_pages (vm_map_t, vm_pindex_t);
984263bc 218static freeer_fcn_t vm_pageout_object_deactivate_pages;
1388df65 219static void vm_req_vmdaemon (void);
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220#endif
221static void vm_pageout_page_stats(void);
222
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223/*
224 * Update
225 */
226void
227vm_fault_ratecheck(void)
228{
229 if (vm_pages_needed) {
230 if (vm_load < 1000)
231 ++vm_load;
232 } else {
233 if (vm_load > 0)
234 --vm_load;
235 }
236}
237
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238/*
239 * vm_pageout_clean:
240 *
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241 * Clean the page and remove it from the laundry. The page must not be
242 * busy on-call.
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243 *
244 * We set the busy bit to cause potential page faults on this page to
245 * block. Note the careful timing, however, the busy bit isn't set till
246 * late and we cannot do anything that will mess with the page.
247 */
248
249static int
57e43348 250vm_pageout_clean(vm_page_t m)
984263bc 251{
5f910b2f 252 vm_object_t object;
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253 vm_page_t mc[2*vm_pageout_page_count];
254 int pageout_count;
255 int ib, is, page_base;
256 vm_pindex_t pindex = m->pindex;
257
258 object = m->object;
259
260 /*
261 * It doesn't cost us anything to pageout OBJT_DEFAULT or OBJT_SWAP
262 * with the new swapper, but we could have serious problems paging
263 * out other object types if there is insufficient memory.
264 *
265 * Unfortunately, checking free memory here is far too late, so the
266 * check has been moved up a procedural level.
267 */
268
269 /*
270 * Don't mess with the page if it's busy, held, or special
271 */
272 if ((m->hold_count != 0) ||
273 ((m->busy != 0) || (m->flags & (PG_BUSY|PG_UNMANAGED)))) {
274 return 0;
275 }
276
277 mc[vm_pageout_page_count] = m;
278 pageout_count = 1;
279 page_base = vm_pageout_page_count;
280 ib = 1;
281 is = 1;
282
283 /*
284 * Scan object for clusterable pages.
285 *
286 * We can cluster ONLY if: ->> the page is NOT
287 * clean, wired, busy, held, or mapped into a
288 * buffer, and one of the following:
289 * 1) The page is inactive, or a seldom used
290 * active page.
291 * -or-
292 * 2) we force the issue.
293 *
294 * During heavy mmap/modification loads the pageout
295 * daemon can really fragment the underlying file
296 * due to flushing pages out of order and not trying
297 * align the clusters (which leave sporatic out-of-order
298 * holes). To solve this problem we do the reverse scan
299 * first and attempt to align our cluster, then do a
300 * forward scan if room remains.
301 */
302
303more:
304 while (ib && pageout_count < vm_pageout_page_count) {
305 vm_page_t p;
306
307 if (ib > pindex) {
308 ib = 0;
309 break;
310 }
311
312 if ((p = vm_page_lookup(object, pindex - ib)) == NULL) {
313 ib = 0;
314 break;
315 }
316 if (((p->queue - p->pc) == PQ_CACHE) ||
317 (p->flags & (PG_BUSY|PG_UNMANAGED)) || p->busy) {
318 ib = 0;
319 break;
320 }
321 vm_page_test_dirty(p);
322 if ((p->dirty & p->valid) == 0 ||
323 p->queue != PQ_INACTIVE ||
324 p->wire_count != 0 || /* may be held by buf cache */
325 p->hold_count != 0) { /* may be undergoing I/O */
326 ib = 0;
327 break;
328 }
329 mc[--page_base] = p;
330 ++pageout_count;
331 ++ib;
332 /*
333 * alignment boundry, stop here and switch directions. Do
334 * not clear ib.
335 */
336 if ((pindex - (ib - 1)) % vm_pageout_page_count == 0)
337 break;
338 }
339
340 while (pageout_count < vm_pageout_page_count &&
341 pindex + is < object->size) {
342 vm_page_t p;
343
344 if ((p = vm_page_lookup(object, pindex + is)) == NULL)
345 break;
346 if (((p->queue - p->pc) == PQ_CACHE) ||
347 (p->flags & (PG_BUSY|PG_UNMANAGED)) || p->busy) {
348 break;
349 }
350 vm_page_test_dirty(p);
351 if ((p->dirty & p->valid) == 0 ||
352 p->queue != PQ_INACTIVE ||
353 p->wire_count != 0 || /* may be held by buf cache */
354 p->hold_count != 0) { /* may be undergoing I/O */
355 break;
356 }
357 mc[page_base + pageout_count] = p;
358 ++pageout_count;
359 ++is;
360 }
361
362 /*
363 * If we exhausted our forward scan, continue with the reverse scan
364 * when possible, even past a page boundry. This catches boundry
365 * conditions.
366 */
367 if (ib && pageout_count < vm_pageout_page_count)
368 goto more;
369
370 /*
371 * we allow reads during pageouts...
372 */
373 return vm_pageout_flush(&mc[page_base], pageout_count, 0);
374}
375
376/*
377 * vm_pageout_flush() - launder the given pages
378 *
379 * The given pages are laundered. Note that we setup for the start of
380 * I/O ( i.e. busy the page ), mark it read-only, and bump the object
381 * reference count all in here rather then in the parent. If we want
382 * the parent to do more sophisticated things we may have to change
383 * the ordering.
384 */
385
386int
57e43348 387vm_pageout_flush(vm_page_t *mc, int count, int flags)
984263bc 388{
5f910b2f 389 vm_object_t object;
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390 int pageout_status[count];
391 int numpagedout = 0;
392 int i;
393
394 /*
395 * Initiate I/O. Bump the vm_page_t->busy counter and
396 * mark the pages read-only.
397 *
398 * We do not have to fixup the clean/dirty bits here... we can
399 * allow the pager to do it after the I/O completes.
400 */
401
402 for (i = 0; i < count; i++) {
403 KASSERT(mc[i]->valid == VM_PAGE_BITS_ALL, ("vm_pageout_flush page %p index %d/%d: partially invalid page", mc[i], i, count));
404 vm_page_io_start(mc[i]);
405 vm_page_protect(mc[i], VM_PROT_READ);
406 }
407
408 object = mc[0]->object;
409 vm_object_pip_add(object, count);
410
411 vm_pager_put_pages(object, mc, count,
412 (flags | ((object == kernel_object) ? VM_PAGER_PUT_SYNC : 0)),
413 pageout_status);
414
415 for (i = 0; i < count; i++) {
416 vm_page_t mt = mc[i];
417
418 switch (pageout_status[i]) {
419 case VM_PAGER_OK:
420 numpagedout++;
421 break;
422 case VM_PAGER_PEND:
423 numpagedout++;
424 break;
425 case VM_PAGER_BAD:
426 /*
427 * Page outside of range of object. Right now we
428 * essentially lose the changes by pretending it
429 * worked.
430 */
431 pmap_clear_modify(mt);
432 vm_page_undirty(mt);
433 break;
434 case VM_PAGER_ERROR:
435 case VM_PAGER_FAIL:
436 /*
437 * If page couldn't be paged out, then reactivate the
438 * page so it doesn't clog the inactive list. (We
439 * will try paging out it again later).
440 */
441 vm_page_activate(mt);
442 break;
443 case VM_PAGER_AGAIN:
444 break;
445 }
446
447 /*
448 * If the operation is still going, leave the page busy to
449 * block all other accesses. Also, leave the paging in
450 * progress indicator set so that we don't attempt an object
451 * collapse.
452 */
453 if (pageout_status[i] != VM_PAGER_PEND) {
454 vm_object_pip_wakeup(object);
455 vm_page_io_finish(mt);
456 if (!vm_page_count_severe() || !vm_page_try_to_cache(mt))
457 vm_page_protect(mt, VM_PROT_READ);
458 }
459 }
460 return numpagedout;
461}
462
463#if !defined(NO_SWAPPING)
464/*
465 * vm_pageout_object_deactivate_pages
466 *
467 * deactivate enough pages to satisfy the inactive target
468 * requirements or if vm_page_proc_limit is set, then
469 * deactivate all of the pages in the object and its
470 * backing_objects.
471 *
472 * The object and map must be locked.
473 */
474static void
57e43348 475vm_pageout_object_deactivate_pages(vm_map_t map, vm_object_t object,
06ecca5a 476 vm_pindex_t desired, int map_remove_only)
984263bc 477{
5f910b2f 478 vm_page_t p, next;
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479 int rcount;
480 int remove_mode;
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481
482 if (object->type == OBJT_DEVICE || object->type == OBJT_PHYS)
483 return;
484
485 while (object) {
486 if (pmap_resident_count(vm_map_pmap(map)) <= desired)
487 return;
488 if (object->paging_in_progress)
489 return;
490
491 remove_mode = map_remove_only;
492 if (object->shadow_count > 1)
493 remove_mode = 1;
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494
495 /*
496 * scan the objects entire memory queue. spl protection is
497 * required to avoid an interrupt unbusy/free race against
498 * our busy check.
499 */
5fd012e0 500 crit_enter();
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501 rcount = object->resident_page_count;
502 p = TAILQ_FIRST(&object->memq);
06ecca5a 503
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504 while (p && (rcount-- > 0)) {
505 int actcount;
06ecca5a 506 if (pmap_resident_count(vm_map_pmap(map)) <= desired) {
5fd012e0 507 crit_exit();
984263bc 508 return;
06ecca5a 509 }
984263bc 510 next = TAILQ_NEXT(p, listq);
12e4aaff 511 mycpu->gd_cnt.v_pdpages++;
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512 if (p->wire_count != 0 ||
513 p->hold_count != 0 ||
514 p->busy != 0 ||
515 (p->flags & (PG_BUSY|PG_UNMANAGED)) ||
516 !pmap_page_exists_quick(vm_map_pmap(map), p)) {
517 p = next;
518 continue;
519 }
520
521 actcount = pmap_ts_referenced(p);
522 if (actcount) {
523 vm_page_flag_set(p, PG_REFERENCED);
524 } else if (p->flags & PG_REFERENCED) {
525 actcount = 1;
526 }
527
528 if ((p->queue != PQ_ACTIVE) &&
529 (p->flags & PG_REFERENCED)) {
530 vm_page_activate(p);
531 p->act_count += actcount;
532 vm_page_flag_clear(p, PG_REFERENCED);
533 } else if (p->queue == PQ_ACTIVE) {
534 if ((p->flags & PG_REFERENCED) == 0) {
535 p->act_count -= min(p->act_count, ACT_DECLINE);
536 if (!remove_mode && (vm_pageout_algorithm || (p->act_count == 0))) {
537 vm_page_protect(p, VM_PROT_NONE);
538 vm_page_deactivate(p);
539 } else {
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540 TAILQ_REMOVE(&vm_page_queues[PQ_ACTIVE].pl, p, pageq);
541 TAILQ_INSERT_TAIL(&vm_page_queues[PQ_ACTIVE].pl, p, pageq);
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542 }
543 } else {
544 vm_page_activate(p);
545 vm_page_flag_clear(p, PG_REFERENCED);
546 if (p->act_count < (ACT_MAX - ACT_ADVANCE))
547 p->act_count += ACT_ADVANCE;
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548 TAILQ_REMOVE(&vm_page_queues[PQ_ACTIVE].pl, p, pageq);
549 TAILQ_INSERT_TAIL(&vm_page_queues[PQ_ACTIVE].pl, p, pageq);
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550 }
551 } else if (p->queue == PQ_INACTIVE) {
552 vm_page_protect(p, VM_PROT_NONE);
553 }
554 p = next;
555 }
5fd012e0 556 crit_exit();
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557 object = object->backing_object;
558 }
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559}
560
561/*
562 * deactivate some number of pages in a map, try to do it fairly, but
563 * that is really hard to do.
564 */
565static void
57e43348 566vm_pageout_map_deactivate_pages(vm_map_t map, vm_pindex_t desired)
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567{
568 vm_map_entry_t tmpe;
569 vm_object_t obj, bigobj;
570 int nothingwired;
571
df4f70a6 572 if (lockmgr(&map->lock, LK_EXCLUSIVE | LK_NOWAIT)) {
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573 return;
574 }
575
576 bigobj = NULL;
577 nothingwired = TRUE;
578
579 /*
580 * first, search out the biggest object, and try to free pages from
581 * that.
582 */
583 tmpe = map->header.next;
584 while (tmpe != &map->header) {
585 if ((tmpe->eflags & MAP_ENTRY_IS_SUB_MAP) == 0) {
586 obj = tmpe->object.vm_object;
587 if ((obj != NULL) && (obj->shadow_count <= 1) &&
588 ((bigobj == NULL) ||
589 (bigobj->resident_page_count < obj->resident_page_count))) {
590 bigobj = obj;
591 }
592 }
593 if (tmpe->wired_count > 0)
594 nothingwired = FALSE;
595 tmpe = tmpe->next;
596 }
597
598 if (bigobj)
599 vm_pageout_object_deactivate_pages(map, bigobj, desired, 0);
600
601 /*
602 * Next, hunt around for other pages to deactivate. We actually
603 * do this search sort of wrong -- .text first is not the best idea.
604 */
605 tmpe = map->header.next;
606 while (tmpe != &map->header) {
607 if (pmap_resident_count(vm_map_pmap(map)) <= desired)
608 break;
609 if ((tmpe->eflags & MAP_ENTRY_IS_SUB_MAP) == 0) {
610 obj = tmpe->object.vm_object;
611 if (obj)
612 vm_pageout_object_deactivate_pages(map, obj, desired, 0);
613 }
614 tmpe = tmpe->next;
615 };
616
617 /*
618 * Remove all mappings if a process is swapped out, this will free page
619 * table pages.
620 */
621 if (desired == 0 && nothingwired)
622 pmap_remove(vm_map_pmap(map),
623 VM_MIN_ADDRESS, VM_MAXUSER_ADDRESS);
624 vm_map_unlock(map);
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625}
626#endif
627
628/*
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629 * Don't try to be fancy - being fancy can lead to vnode deadlocks. We
630 * only do it for OBJT_DEFAULT and OBJT_SWAP objects which we know can
631 * be trivially freed.
984263bc 632 */
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633void
634vm_pageout_page_free(vm_page_t m) {
635 vm_object_t object = m->object;
636 int type = object->type;
637
638 if (type == OBJT_SWAP || type == OBJT_DEFAULT)
639 vm_object_reference(object);
640 vm_page_busy(m);
641 vm_page_protect(m, VM_PROT_NONE);
642 vm_page_free(m);
643 if (type == OBJT_SWAP || type == OBJT_DEFAULT)
644 vm_object_deallocate(object);
645}
646
647/*
648 * vm_pageout_scan does the dirty work for the pageout daemon.
649 */
8fa76237
MD
650
651struct vm_pageout_scan_info {
652 struct proc *bigproc;
653 vm_offset_t bigsize;
654};
655
656static int vm_pageout_scan_callback(struct proc *p, void *data);
657
984263bc
MD
658static void
659vm_pageout_scan(int pass)
660{
8fa76237 661 struct vm_pageout_scan_info info;
984263bc
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662 vm_page_t m, next;
663 struct vm_page marker;
664 int page_shortage, maxscan, pcount;
665 int addl_page_shortage, addl_page_shortage_init;
984263bc
MD
666 vm_object_t object;
667 int actcount;
668 int vnodes_skipped = 0;
669 int maxlaunder;
984263bc
MD
670
671 /*
672 * Do whatever cleanup that the pmap code can.
673 */
674 pmap_collect();
675
676 addl_page_shortage_init = vm_pageout_deficit;
677 vm_pageout_deficit = 0;
678
679 /*
680 * Calculate the number of pages we want to either free or move
681 * to the cache.
682 */
683 page_shortage = vm_paging_target() + addl_page_shortage_init;
684
685 /*
686 * Initialize our marker
687 */
688 bzero(&marker, sizeof(marker));
689 marker.flags = PG_BUSY | PG_FICTITIOUS | PG_MARKER;
690 marker.queue = PQ_INACTIVE;
691 marker.wire_count = 1;
692
693 /*
694 * Start scanning the inactive queue for pages we can move to the
695 * cache or free. The scan will stop when the target is reached or
696 * we have scanned the entire inactive queue. Note that m->act_count
697 * is not used to form decisions for the inactive queue, only for the
698 * active queue.
699 *
700 * maxlaunder limits the number of dirty pages we flush per scan.
701 * For most systems a smaller value (16 or 32) is more robust under
702 * extreme memory and disk pressure because any unnecessary writes
703 * to disk can result in extreme performance degredation. However,
704 * systems with excessive dirty pages (especially when MAP_NOSYNC is
705 * used) will die horribly with limited laundering. If the pageout
706 * daemon cannot clean enough pages in the first pass, we let it go
707 * all out in succeeding passes.
708 */
709 if ((maxlaunder = vm_max_launder) <= 1)
710 maxlaunder = 1;
711 if (pass)
712 maxlaunder = 10000;
713
06ecca5a 714 /*
5fd012e0
MD
715 * We will generally be in a critical section throughout the
716 * scan, but we can release it temporarily when we are sitting on a
717 * non-busy page without fear. this is required to prevent an
718 * interrupt from unbusying or freeing a page prior to our busy
719 * check, leaving us on the wrong queue or checking the wrong
720 * page.
06ecca5a 721 */
5fd012e0 722 crit_enter();
984263bc
MD
723rescan0:
724 addl_page_shortage = addl_page_shortage_init;
12e4aaff 725 maxscan = vmstats.v_inactive_count;
984263bc
MD
726 for (m = TAILQ_FIRST(&vm_page_queues[PQ_INACTIVE].pl);
727 m != NULL && maxscan-- > 0 && page_shortage > 0;
06ecca5a
MD
728 m = next
729 ) {
12e4aaff 730 mycpu->gd_cnt.v_pdpages++;
984263bc 731
06ecca5a
MD
732 /*
733 * Give interrupts a chance
734 */
5fd012e0
MD
735 crit_exit();
736 crit_enter();
984263bc 737
06ecca5a
MD
738 /*
739 * It's easier for some of the conditions below to just loop
740 * and catch queue changes here rather then check everywhere
741 * else.
742 */
743 if (m->queue != PQ_INACTIVE)
744 goto rescan0;
984263bc
MD
745 next = TAILQ_NEXT(m, pageq);
746
747 /*
748 * skip marker pages
749 */
750 if (m->flags & PG_MARKER)
751 continue;
752
753 /*
754 * A held page may be undergoing I/O, so skip it.
755 */
756 if (m->hold_count) {
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MD
757 TAILQ_REMOVE(&vm_page_queues[PQ_INACTIVE].pl, m, pageq);
758 TAILQ_INSERT_TAIL(&vm_page_queues[PQ_INACTIVE].pl, m, pageq);
984263bc
MD
759 addl_page_shortage++;
760 continue;
761 }
06ecca5a 762
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MD
763 /*
764 * Dont mess with busy pages, keep in the front of the
765 * queue, most likely are being paged out.
766 */
767 if (m->busy || (m->flags & PG_BUSY)) {
768 addl_page_shortage++;
769 continue;
770 }
771
984263bc 772 if (m->object->ref_count == 0) {
06ecca5a
MD
773 /*
774 * If the object is not being used, we ignore previous
775 * references.
776 */
984263bc
MD
777 vm_page_flag_clear(m, PG_REFERENCED);
778 pmap_clear_reference(m);
779
984263bc 780 } else if (((m->flags & PG_REFERENCED) == 0) &&
06ecca5a
MD
781 (actcount = pmap_ts_referenced(m))) {
782 /*
783 * Otherwise, if the page has been referenced while
784 * in the inactive queue, we bump the "activation
785 * count" upwards, making it less likely that the
786 * page will be added back to the inactive queue
787 * prematurely again. Here we check the page tables
788 * (or emulated bits, if any), given the upper level
789 * VM system not knowing anything about existing
790 * references.
791 */
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MD
792 vm_page_activate(m);
793 m->act_count += (actcount + ACT_ADVANCE);
794 continue;
795 }
796
797 /*
798 * If the upper level VM system knows about any page
799 * references, we activate the page. We also set the
800 * "activation count" higher than normal so that we will less
801 * likely place pages back onto the inactive queue again.
802 */
803 if ((m->flags & PG_REFERENCED) != 0) {
804 vm_page_flag_clear(m, PG_REFERENCED);
805 actcount = pmap_ts_referenced(m);
806 vm_page_activate(m);
807 m->act_count += (actcount + ACT_ADVANCE + 1);
808 continue;
809 }
810
811 /*
812 * If the upper level VM system doesn't know anything about
813 * the page being dirty, we have to check for it again. As
814 * far as the VM code knows, any partially dirty pages are
815 * fully dirty.
41a01a4d
MD
816 *
817 * Pages marked PG_WRITEABLE may be mapped into the user
818 * address space of a process running on another cpu. A
819 * user process (without holding the MP lock) running on
820 * another cpu may be able to touch the page while we are
821 * trying to remove it. To prevent this from occuring we
822 * must call pmap_remove_all() or otherwise make the page
823 * read-only. If the race occured pmap_remove_all() is
824 * responsible for setting m->dirty.
984263bc
MD
825 */
826 if (m->dirty == 0) {
827 vm_page_test_dirty(m);
41a01a4d
MD
828#if 0
829 if (m->dirty == 0 && (m->flags & PG_WRITEABLE) != 0)
830 pmap_remove_all(m);
831#endif
984263bc
MD
832 } else {
833 vm_page_dirty(m);
834 }
835
984263bc 836 if (m->valid == 0) {
41a01a4d
MD
837 /*
838 * Invalid pages can be easily freed
839 */
984263bc 840 vm_pageout_page_free(m);
12e4aaff 841 mycpu->gd_cnt.v_dfree++;
984263bc 842 --page_shortage;
984263bc
MD
843 } else if (m->dirty == 0) {
844 /*
41a01a4d
MD
845 * Clean pages can be placed onto the cache queue.
846 * This effectively frees them.
984263bc
MD
847 */
848 vm_page_cache(m);
849 --page_shortage;
850 } else if ((m->flags & PG_WINATCFLS) == 0 && pass == 0) {
851 /*
852 * Dirty pages need to be paged out, but flushing
853 * a page is extremely expensive verses freeing
854 * a clean page. Rather then artificially limiting
855 * the number of pages we can flush, we instead give
856 * dirty pages extra priority on the inactive queue
857 * by forcing them to be cycled through the queue
858 * twice before being flushed, after which the
859 * (now clean) page will cycle through once more
860 * before being freed. This significantly extends
861 * the thrash point for a heavily loaded machine.
862 */
984263bc
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863 vm_page_flag_set(m, PG_WINATCFLS);
864 TAILQ_REMOVE(&vm_page_queues[PQ_INACTIVE].pl, m, pageq);
865 TAILQ_INSERT_TAIL(&vm_page_queues[PQ_INACTIVE].pl, m, pageq);
984263bc
MD
866 } else if (maxlaunder > 0) {
867 /*
868 * We always want to try to flush some dirty pages if
869 * we encounter them, to keep the system stable.
870 * Normally this number is small, but under extreme
871 * pressure where there are insufficient clean pages
872 * on the inactive queue, we may have to go all out.
873 */
874 int swap_pageouts_ok;
875 struct vnode *vp = NULL;
876
877 object = m->object;
878
879 if ((object->type != OBJT_SWAP) && (object->type != OBJT_DEFAULT)) {
880 swap_pageouts_ok = 1;
881 } else {
882 swap_pageouts_ok = !(defer_swap_pageouts || disable_swap_pageouts);
883 swap_pageouts_ok |= (!disable_swap_pageouts && defer_swap_pageouts &&
884 vm_page_count_min());
885
886 }
887
888 /*
889 * We don't bother paging objects that are "dead".
890 * Those objects are in a "rundown" state.
891 */
892 if (!swap_pageouts_ok || (object->flags & OBJ_DEAD)) {
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MD
893 TAILQ_REMOVE(&vm_page_queues[PQ_INACTIVE].pl, m, pageq);
894 TAILQ_INSERT_TAIL(&vm_page_queues[PQ_INACTIVE].pl, m, pageq);
984263bc
MD
895 continue;
896 }
897
898 /*
899 * The object is already known NOT to be dead. It
900 * is possible for the vget() to block the whole
901 * pageout daemon, but the new low-memory handling
902 * code should prevent it.
903 *
904 * The previous code skipped locked vnodes and, worse,
905 * reordered pages in the queue. This results in
906 * completely non-deterministic operation because,
907 * quite often, a vm_fault has initiated an I/O and
908 * is holding a locked vnode at just the point where
909 * the pageout daemon is woken up.
910 *
911 * We can't wait forever for the vnode lock, we might
912 * deadlock due to a vn_read() getting stuck in
913 * vm_wait while holding this vnode. We skip the
914 * vnode if we can't get it in a reasonable amount
915 * of time.
916 */
917
918 if (object->type == OBJT_VNODE) {
919 vp = object->handle;
920
87de5057 921 if (vget(vp, LK_EXCLUSIVE|LK_NOOBJ|LK_TIMELOCK)) {
984263bc
MD
922 ++pageout_lock_miss;
923 if (object->flags & OBJ_MIGHTBEDIRTY)
924 vnodes_skipped++;
925 continue;
926 }
927
928 /*
929 * The page might have been moved to another
930 * queue during potential blocking in vget()
931 * above. The page might have been freed and
932 * reused for another vnode. The object might
933 * have been reused for another vnode.
934 */
935 if (m->queue != PQ_INACTIVE ||
936 m->object != object ||
937 object->handle != vp) {
938 if (object->flags & OBJ_MIGHTBEDIRTY)
939 vnodes_skipped++;
940 vput(vp);
941 continue;
942 }
943
944 /*
945 * The page may have been busied during the
946 * blocking in vput(); We don't move the
947 * page back onto the end of the queue so that
948 * statistics are more correct if we don't.
949 */
950 if (m->busy || (m->flags & PG_BUSY)) {
951 vput(vp);
952 continue;
953 }
954
955 /*
956 * If the page has become held it might
957 * be undergoing I/O, so skip it
958 */
959 if (m->hold_count) {
984263bc
MD
960 TAILQ_REMOVE(&vm_page_queues[PQ_INACTIVE].pl, m, pageq);
961 TAILQ_INSERT_TAIL(&vm_page_queues[PQ_INACTIVE].pl, m, pageq);
984263bc
MD
962 if (object->flags & OBJ_MIGHTBEDIRTY)
963 vnodes_skipped++;
964 vput(vp);
965 continue;
966 }
967 }
968
969 /*
970 * If a page is dirty, then it is either being washed
971 * (but not yet cleaned) or it is still in the
972 * laundry. If it is still in the laundry, then we
973 * start the cleaning operation.
974 *
975 * This operation may cluster, invalidating the 'next'
976 * pointer. To prevent an inordinate number of
977 * restarts we use our marker to remember our place.
978 *
979 * decrement page_shortage on success to account for
980 * the (future) cleaned page. Otherwise we could wind
981 * up laundering or cleaning too many pages.
982 */
984263bc 983 TAILQ_INSERT_AFTER(&vm_page_queues[PQ_INACTIVE].pl, m, &marker, pageq);
984263bc
MD
984 if (vm_pageout_clean(m) != 0) {
985 --page_shortage;
986 --maxlaunder;
987 }
984263bc
MD
988 next = TAILQ_NEXT(&marker, pageq);
989 TAILQ_REMOVE(&vm_page_queues[PQ_INACTIVE].pl, &marker, pageq);
984263bc
MD
990 if (vp != NULL)
991 vput(vp);
992 }
993 }
994
995 /*
996 * Compute the number of pages we want to try to move from the
997 * active queue to the inactive queue.
998 */
999 page_shortage = vm_paging_target() +
12e4aaff 1000 vmstats.v_inactive_target - vmstats.v_inactive_count;
984263bc
MD
1001 page_shortage += addl_page_shortage;
1002
1003 /*
1004 * Scan the active queue for things we can deactivate. We nominally
1005 * track the per-page activity counter and use it to locate
1006 * deactivation candidates.
06ecca5a 1007 *
5fd012e0 1008 * NOTE: we are still in a critical section.
984263bc 1009 */
12e4aaff 1010 pcount = vmstats.v_active_count;
984263bc
MD
1011 m = TAILQ_FIRST(&vm_page_queues[PQ_ACTIVE].pl);
1012
1013 while ((m != NULL) && (pcount-- > 0) && (page_shortage > 0)) {
06ecca5a
MD
1014 /*
1015 * Give interrupts a chance.
1016 */
5fd012e0
MD
1017 crit_exit();
1018 crit_enter();
984263bc
MD
1019
1020 /*
06ecca5a 1021 * If the page was ripped out from under us, just stop.
984263bc 1022 */
06ecca5a 1023 if (m->queue != PQ_ACTIVE)
984263bc 1024 break;
984263bc 1025 next = TAILQ_NEXT(m, pageq);
06ecca5a 1026
984263bc
MD
1027 /*
1028 * Don't deactivate pages that are busy.
1029 */
1030 if ((m->busy != 0) ||
1031 (m->flags & PG_BUSY) ||
1032 (m->hold_count != 0)) {
984263bc
MD
1033 TAILQ_REMOVE(&vm_page_queues[PQ_ACTIVE].pl, m, pageq);
1034 TAILQ_INSERT_TAIL(&vm_page_queues[PQ_ACTIVE].pl, m, pageq);
984263bc
MD
1035 m = next;
1036 continue;
1037 }
1038
1039 /*
1040 * The count for pagedaemon pages is done after checking the
1041 * page for eligibility...
1042 */
12e4aaff 1043 mycpu->gd_cnt.v_pdpages++;
984263bc
MD
1044
1045 /*
1046 * Check to see "how much" the page has been used.
1047 */
1048 actcount = 0;
1049 if (m->object->ref_count != 0) {
1050 if (m->flags & PG_REFERENCED) {
1051 actcount += 1;
1052 }
1053 actcount += pmap_ts_referenced(m);
1054 if (actcount) {
1055 m->act_count += ACT_ADVANCE + actcount;
1056 if (m->act_count > ACT_MAX)
1057 m->act_count = ACT_MAX;
1058 }
1059 }
1060
1061 /*
1062 * Since we have "tested" this bit, we need to clear it now.
1063 */
1064 vm_page_flag_clear(m, PG_REFERENCED);
1065
1066 /*
1067 * Only if an object is currently being used, do we use the
1068 * page activation count stats.
1069 */
1070 if (actcount && (m->object->ref_count != 0)) {
984263bc
MD
1071 TAILQ_REMOVE(&vm_page_queues[PQ_ACTIVE].pl, m, pageq);
1072 TAILQ_INSERT_TAIL(&vm_page_queues[PQ_ACTIVE].pl, m, pageq);
984263bc
MD
1073 } else {
1074 m->act_count -= min(m->act_count, ACT_DECLINE);
1075 if (vm_pageout_algorithm ||
1076 m->object->ref_count == 0 ||
b5ccee96 1077 m->act_count < pass) {
984263bc
MD
1078 page_shortage--;
1079 if (m->object->ref_count == 0) {
1080 vm_page_protect(m, VM_PROT_NONE);
1081 if (m->dirty == 0)
1082 vm_page_cache(m);
1083 else
1084 vm_page_deactivate(m);
1085 } else {
1086 vm_page_deactivate(m);
1087 }
1088 } else {
984263bc
MD
1089 TAILQ_REMOVE(&vm_page_queues[PQ_ACTIVE].pl, m, pageq);
1090 TAILQ_INSERT_TAIL(&vm_page_queues[PQ_ACTIVE].pl, m, pageq);
984263bc
MD
1091 }
1092 }
1093 m = next;
1094 }
1095
984263bc
MD
1096 /*
1097 * We try to maintain some *really* free pages, this allows interrupt
1098 * code to be guaranteed space. Since both cache and free queues
1099 * are considered basically 'free', moving pages from cache to free
1100 * does not effect other calculations.
06ecca5a 1101 *
5fd012e0 1102 * NOTE: we are still in a critical section.
984263bc
MD
1103 */
1104
12e4aaff 1105 while (vmstats.v_free_count < vmstats.v_free_reserved) {
984263bc
MD
1106 static int cache_rover = 0;
1107 m = vm_page_list_find(PQ_CACHE, cache_rover, FALSE);
1108 if (!m)
1109 break;
1110 if ((m->flags & (PG_BUSY|PG_UNMANAGED)) ||
1111 m->busy ||
1112 m->hold_count ||
1113 m->wire_count) {
1114#ifdef INVARIANTS
1115 printf("Warning: busy page %p found in cache\n", m);
1116#endif
1117 vm_page_deactivate(m);
1118 continue;
1119 }
1120 cache_rover = (cache_rover + PQ_PRIME2) & PQ_L2_MASK;
1121 vm_pageout_page_free(m);
12e4aaff 1122 mycpu->gd_cnt.v_dfree++;
984263bc 1123 }
06ecca5a 1124
5fd012e0 1125 crit_exit();
984263bc
MD
1126
1127#if !defined(NO_SWAPPING)
1128 /*
1129 * Idle process swapout -- run once per second.
1130 */
1131 if (vm_swap_idle_enabled) {
1132 static long lsec;
1133 if (time_second != lsec) {
1134 vm_pageout_req_swapout |= VM_SWAP_IDLE;
1135 vm_req_vmdaemon();
1136 lsec = time_second;
1137 }
1138 }
1139#endif
1140
1141 /*
1142 * If we didn't get enough free pages, and we have skipped a vnode
1143 * in a writeable object, wakeup the sync daemon. And kick swapout
1144 * if we did not get enough free pages.
1145 */
1146 if (vm_paging_target() > 0) {
1147 if (vnodes_skipped && vm_page_count_min())
418ff780 1148 speedup_syncer();
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MD
1149#if !defined(NO_SWAPPING)
1150 if (vm_swap_enabled && vm_page_count_target()) {
1151 vm_req_vmdaemon();
1152 vm_pageout_req_swapout |= VM_SWAP_NORMAL;
1153 }
1154#endif
1155 }
1156
1157 /*
1158 * If we are out of swap and were not able to reach our paging
1159 * target, kill the largest process.
1160 */
1161 if ((vm_swap_size < 64 && vm_page_count_min()) ||
1162 (swap_pager_full && vm_paging_target() > 0)) {
1163#if 0
1164 if ((vm_swap_size < 64 || swap_pager_full) && vm_page_count_min()) {
1165#endif
8fa76237
MD
1166 info.bigproc = NULL;
1167 info.bigsize = 0;
1168 allproc_scan(vm_pageout_scan_callback, &info);
1169 if (info.bigproc != NULL) {
1170 killproc(info.bigproc, "out of swap space");
1171 info.bigproc->p_nice = PRIO_MIN;
1172 info.bigproc->p_usched->resetpriority(&info.bigproc->p_lwp);
12e4aaff 1173 wakeup(&vmstats.v_free_count);
8fa76237 1174 PRELE(info.bigproc);
984263bc
MD
1175 }
1176 }
1177}
1178
8fa76237
MD
1179static int
1180vm_pageout_scan_callback(struct proc *p, void *data)
1181{
1182 struct vm_pageout_scan_info *info = data;
1183 vm_offset_t size;
1184
1185 /*
1186 * if this is a system process, skip it
1187 */
1188 if ((p->p_flag & P_SYSTEM) || (p->p_pid == 1) ||
1189 ((p->p_pid < 48) && (vm_swap_size != 0))) {
1190 return (0);
1191 }
1192
1193 /*
1194 * if the process is in a non-running type state,
1195 * don't touch it.
1196 */
1197 if (p->p_stat != SRUN && p->p_stat != SSLEEP) {
1198 return (0);
1199 }
1200
1201 /*
1202 * get the process size
1203 */
1204 size = vmspace_resident_count(p->p_vmspace) +
1205 vmspace_swap_count(p->p_vmspace);
1206
1207 /*
1208 * If the this process is bigger than the biggest one
1209 * remember it.
1210 */
1211 if (size > info->bigsize) {
1212 if (info->bigproc)
1213 PRELE(info->bigproc);
1214 PHOLD(p);
1215 info->bigproc = p;
1216 info->bigsize = size;
1217 }
1218 return(0);
1219}
1220
984263bc
MD
1221/*
1222 * This routine tries to maintain the pseudo LRU active queue,
1223 * so that during long periods of time where there is no paging,
1224 * that some statistic accumulation still occurs. This code
1225 * helps the situation where paging just starts to occur.
1226 */
1227static void
57e43348 1228vm_pageout_page_stats(void)
984263bc 1229{
984263bc
MD
1230 vm_page_t m,next;
1231 int pcount,tpcount; /* Number of pages to check */
1232 static int fullintervalcount = 0;
1233 int page_shortage;
984263bc
MD
1234
1235 page_shortage =
12e4aaff
MD
1236 (vmstats.v_inactive_target + vmstats.v_cache_max + vmstats.v_free_min) -
1237 (vmstats.v_free_count + vmstats.v_inactive_count + vmstats.v_cache_count);
984263bc
MD
1238
1239 if (page_shortage <= 0)
1240 return;
1241
5fd012e0 1242 crit_enter();
984263bc 1243
12e4aaff 1244 pcount = vmstats.v_active_count;
984263bc
MD
1245 fullintervalcount += vm_pageout_stats_interval;
1246 if (fullintervalcount < vm_pageout_full_stats_interval) {
12e4aaff 1247 tpcount = (vm_pageout_stats_max * vmstats.v_active_count) / vmstats.v_page_count;
984263bc
MD
1248 if (pcount > tpcount)
1249 pcount = tpcount;
1250 } else {
1251 fullintervalcount = 0;
1252 }
1253
1254 m = TAILQ_FIRST(&vm_page_queues[PQ_ACTIVE].pl);
1255 while ((m != NULL) && (pcount-- > 0)) {
1256 int actcount;
1257
1258 if (m->queue != PQ_ACTIVE) {
1259 break;
1260 }
1261
1262 next = TAILQ_NEXT(m, pageq);
1263 /*
1264 * Don't deactivate pages that are busy.
1265 */
1266 if ((m->busy != 0) ||
1267 (m->flags & PG_BUSY) ||
1268 (m->hold_count != 0)) {
984263bc
MD
1269 TAILQ_REMOVE(&vm_page_queues[PQ_ACTIVE].pl, m, pageq);
1270 TAILQ_INSERT_TAIL(&vm_page_queues[PQ_ACTIVE].pl, m, pageq);
984263bc
MD
1271 m = next;
1272 continue;
1273 }
1274
1275 actcount = 0;
1276 if (m->flags & PG_REFERENCED) {
1277 vm_page_flag_clear(m, PG_REFERENCED);
1278 actcount += 1;
1279 }
1280
1281 actcount += pmap_ts_referenced(m);
1282 if (actcount) {
1283 m->act_count += ACT_ADVANCE + actcount;
1284 if (m->act_count > ACT_MAX)
1285 m->act_count = ACT_MAX;
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1286 TAILQ_REMOVE(&vm_page_queues[PQ_ACTIVE].pl, m, pageq);
1287 TAILQ_INSERT_TAIL(&vm_page_queues[PQ_ACTIVE].pl, m, pageq);
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1288 } else {
1289 if (m->act_count == 0) {
1290 /*
1291 * We turn off page access, so that we have
1292 * more accurate RSS stats. We don't do this
1293 * in the normal page deactivation when the
1294 * system is loaded VM wise, because the
1295 * cost of the large number of page protect
1296 * operations would be higher than the value
1297 * of doing the operation.
1298 */
1299 vm_page_protect(m, VM_PROT_NONE);
1300 vm_page_deactivate(m);
1301 } else {
1302 m->act_count -= min(m->act_count, ACT_DECLINE);
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1303 TAILQ_REMOVE(&vm_page_queues[PQ_ACTIVE].pl, m, pageq);
1304 TAILQ_INSERT_TAIL(&vm_page_queues[PQ_ACTIVE].pl, m, pageq);
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1305 }
1306 }
1307
1308 m = next;
1309 }
5fd012e0 1310 crit_exit();
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1311}
1312
1313static int
57e43348 1314vm_pageout_free_page_calc(vm_size_t count)
984263bc 1315{
12e4aaff 1316 if (count < vmstats.v_page_count)
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1317 return 0;
1318 /*
1319 * free_reserved needs to include enough for the largest swap pager
1320 * structures plus enough for any pv_entry structs when paging.
1321 */
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1322 if (vmstats.v_page_count > 1024)
1323 vmstats.v_free_min = 4 + (vmstats.v_page_count - 1024) / 200;
984263bc 1324 else
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1325 vmstats.v_free_min = 4;
1326 vmstats.v_pageout_free_min = (2*MAXBSIZE)/PAGE_SIZE +
1327 vmstats.v_interrupt_free_min;
1328 vmstats.v_free_reserved = vm_pageout_page_count +
1329 vmstats.v_pageout_free_min + (count / 768) + PQ_L2_SIZE;
1330 vmstats.v_free_severe = vmstats.v_free_min / 2;
1331 vmstats.v_free_min += vmstats.v_free_reserved;
1332 vmstats.v_free_severe += vmstats.v_free_reserved;
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1333 return 1;
1334}
1335
1336
1337/*
1338 * vm_pageout is the high level pageout daemon.
1339 */
1340static void
57e43348 1341vm_pageout(void)
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1342{
1343 int pass;
1344
1345 /*
1346 * Initialize some paging parameters.
1347 */
1348
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1349 vmstats.v_interrupt_free_min = 2;
1350 if (vmstats.v_page_count < 2000)
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1351 vm_pageout_page_count = 8;
1352
12e4aaff 1353 vm_pageout_free_page_calc(vmstats.v_page_count);
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1354 /*
1355 * v_free_target and v_cache_min control pageout hysteresis. Note
1356 * that these are more a measure of the VM cache queue hysteresis
1357 * then the VM free queue. Specifically, v_free_target is the
1358 * high water mark (free+cache pages).
1359 *
1360 * v_free_reserved + v_cache_min (mostly means v_cache_min) is the
1361 * low water mark, while v_free_min is the stop. v_cache_min must
1362 * be big enough to handle memory needs while the pageout daemon
1363 * is signalled and run to free more pages.
1364 */
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1365 if (vmstats.v_free_count > 6144)
1366 vmstats.v_free_target = 4 * vmstats.v_free_min + vmstats.v_free_reserved;
984263bc 1367 else
12e4aaff 1368 vmstats.v_free_target = 2 * vmstats.v_free_min + vmstats.v_free_reserved;
984263bc 1369
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1370 if (vmstats.v_free_count > 2048) {
1371 vmstats.v_cache_min = vmstats.v_free_target;
1372 vmstats.v_cache_max = 2 * vmstats.v_cache_min;
1373 vmstats.v_inactive_target = (3 * vmstats.v_free_target) / 2;
984263bc 1374 } else {
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1375 vmstats.v_cache_min = 0;
1376 vmstats.v_cache_max = 0;
1377 vmstats.v_inactive_target = vmstats.v_free_count / 4;
984263bc 1378 }
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1379 if (vmstats.v_inactive_target > vmstats.v_free_count / 3)
1380 vmstats.v_inactive_target = vmstats.v_free_count / 3;
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1381
1382 /* XXX does not really belong here */
1383 if (vm_page_max_wired == 0)
12e4aaff 1384 vm_page_max_wired = vmstats.v_free_count / 3;
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1385
1386 if (vm_pageout_stats_max == 0)
12e4aaff 1387 vm_pageout_stats_max = vmstats.v_free_target;
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1388
1389 /*
1390 * Set interval in seconds for stats scan.
1391 */
1392 if (vm_pageout_stats_interval == 0)
1393 vm_pageout_stats_interval = 5;
1394 if (vm_pageout_full_stats_interval == 0)
1395 vm_pageout_full_stats_interval = vm_pageout_stats_interval * 4;
1396
1397
1398 /*
1399 * Set maximum free per pass
1400 */
1401 if (vm_pageout_stats_free_max == 0)
1402 vm_pageout_stats_free_max = 5;
1403
1404 swap_pager_swap_init();
1405 pass = 0;
1406 /*
1407 * The pageout daemon is never done, so loop forever.
1408 */
1409 while (TRUE) {
1410 int error;
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1411
1412 /*
1413 * If we have enough free memory, wakeup waiters. Do
1414 * not clear vm_pages_needed until we reach our target,
1415 * otherwise we may be woken up over and over again and
1416 * waste a lot of cpu.
1417 */
5fd012e0 1418 crit_enter();
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1419 if (vm_pages_needed && !vm_page_count_min()) {
1420 if (vm_paging_needed() <= 0)
1421 vm_pages_needed = 0;
12e4aaff 1422 wakeup(&vmstats.v_free_count);
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1423 }
1424 if (vm_pages_needed) {
1425 /*
1426 * Still not done, take a second pass without waiting
1427 * (unlimited dirty cleaning), otherwise sleep a bit
1428 * and try again.
1429 */
1430 ++pass;
1431 if (pass > 1)
377d4740 1432 tsleep(&vm_pages_needed, 0, "psleep", hz/2);
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1433 } else {
1434 /*
1435 * Good enough, sleep & handle stats. Prime the pass
1436 * for the next run.
1437 */
1438 if (pass > 1)
1439 pass = 1;
1440 else
1441 pass = 0;
1442 error = tsleep(&vm_pages_needed,
377d4740 1443 0, "psleep", vm_pageout_stats_interval * hz);
984263bc 1444 if (error && !vm_pages_needed) {
5fd012e0 1445 crit_exit();
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1446 pass = 0;
1447 vm_pageout_page_stats();
1448 continue;
1449 }
1450 }
1451
1452 if (vm_pages_needed)
12e4aaff 1453 mycpu->gd_cnt.v_pdwakeups++;
5fd012e0 1454 crit_exit();
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1455 vm_pageout_scan(pass);
1456 vm_pageout_deficit = 0;
1457 }
1458}
1459
1460void
57e43348 1461pagedaemon_wakeup(void)
984263bc 1462{
bc6dffab 1463 if (!vm_pages_needed && curthread != pagethread) {
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1464 vm_pages_needed++;
1465 wakeup(&vm_pages_needed);
1466 }
1467}
1468
1469#if !defined(NO_SWAPPING)
1470static void
57e43348 1471vm_req_vmdaemon(void)
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1472{
1473 static int lastrun = 0;
1474
1475 if ((ticks > (lastrun + hz)) || (ticks < lastrun)) {
1476 wakeup(&vm_daemon_needed);
1477 lastrun = ticks;
1478 }
1479}
1480
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1481static int vm_daemon_callback(struct proc *p, void *data __unused);
1482
984263bc 1483static void
57e43348 1484vm_daemon(void)
984263bc 1485{
984263bc 1486 while (TRUE) {
377d4740 1487 tsleep(&vm_daemon_needed, 0, "psleep", 0);
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1488 if (vm_pageout_req_swapout) {
1489 swapout_procs(vm_pageout_req_swapout);
1490 vm_pageout_req_swapout = 0;
1491 }
1492 /*
1493 * scan the processes for exceeding their rlimits or if
1494 * process is swapped out -- deactivate pages
1495 */
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1496 allproc_scan(vm_daemon_callback, NULL);
1497 }
1498}
984263bc 1499
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1500static int
1501vm_daemon_callback(struct proc *p, void *data __unused)
1502{
1503 vm_pindex_t limit, size;
984263bc 1504
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1505 /*
1506 * if this is a system process or if we have already
1507 * looked at this process, skip it.
1508 */
1509 if (p->p_flag & (P_SYSTEM | P_WEXIT))
1510 return (0);
984263bc 1511
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1512 /*
1513 * if the process is in a non-running type state,
1514 * don't touch it.
1515 */
1516 if (p->p_stat != SRUN && p->p_stat != SSLEEP)
1517 return (0);
984263bc 1518
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1519 /*
1520 * get a limit
1521 */
1522 limit = OFF_TO_IDX(qmin(p->p_rlimit[RLIMIT_RSS].rlim_cur,
1523 p->p_rlimit[RLIMIT_RSS].rlim_max));
1524
1525 /*
1526 * let processes that are swapped out really be
1527 * swapped out. Set the limit to nothing to get as
1528 * many pages out to swap as possible.
1529 */
1530 if (p->p_flag & P_SWAPPEDOUT)
1531 limit = 0;
1532
1533 size = vmspace_resident_count(p->p_vmspace);
1534 if (limit >= 0 && size >= limit) {
1535 vm_pageout_map_deactivate_pages(
1536 &p->p_vmspace->vm_map, limit);
984263bc 1537 }
8fa76237 1538 return (0);
984263bc 1539}
8fa76237 1540
984263bc 1541#endif