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[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 $
08f2f1bb 69 * $DragonFly: src/sys/vm/vm_pageout.c,v 1.30 2007/02/03 17:05:59 corecode 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,
c439ad8f 412 (flags | ((object == &kernel_object) ? VM_PAGER_PUT_SYNC : 0)),
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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 */
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474static int vm_pageout_object_deactivate_pages_callback(vm_page_t, void *);
475
984263bc 476static void
57e43348 477vm_pageout_object_deactivate_pages(vm_map_t map, vm_object_t object,
06ecca5a 478 vm_pindex_t desired, int map_remove_only)
984263bc 479{
1f804340 480 struct rb_vm_page_scan_info info;
984263bc 481 int remove_mode;
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482
483 if (object->type == OBJT_DEVICE || object->type == OBJT_PHYS)
484 return;
485
486 while (object) {
487 if (pmap_resident_count(vm_map_pmap(map)) <= desired)
488 return;
489 if (object->paging_in_progress)
490 return;
491
492 remove_mode = map_remove_only;
493 if (object->shadow_count > 1)
494 remove_mode = 1;
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495
496 /*
497 * scan the objects entire memory queue. spl protection is
498 * required to avoid an interrupt unbusy/free race against
499 * our busy check.
500 */
5fd012e0 501 crit_enter();
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502 info.limit = remove_mode;
503 info.map = map;
504 info.desired = desired;
505 vm_page_rb_tree_RB_SCAN(&object->rb_memq, NULL,
506 vm_pageout_object_deactivate_pages_callback,
507 &info
508 );
509 crit_exit();
510 object = object->backing_object;
511 }
512}
513
514static int
515vm_pageout_object_deactivate_pages_callback(vm_page_t p, void *data)
516{
517 struct rb_vm_page_scan_info *info = data;
518 int actcount;
984263bc 519
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520 if (pmap_resident_count(vm_map_pmap(info->map)) <= info->desired) {
521 return(-1);
522 }
523 mycpu->gd_cnt.v_pdpages++;
524 if (p->wire_count != 0 || p->hold_count != 0 || p->busy != 0 ||
525 (p->flags & (PG_BUSY|PG_UNMANAGED)) ||
526 !pmap_page_exists_quick(vm_map_pmap(info->map), p)) {
527 return(0);
528 }
984263bc 529
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530 actcount = pmap_ts_referenced(p);
531 if (actcount) {
532 vm_page_flag_set(p, PG_REFERENCED);
533 } else if (p->flags & PG_REFERENCED) {
534 actcount = 1;
535 }
536
537 if ((p->queue != PQ_ACTIVE) &&
538 (p->flags & PG_REFERENCED)) {
539 vm_page_activate(p);
540 p->act_count += actcount;
541 vm_page_flag_clear(p, PG_REFERENCED);
542 } else if (p->queue == PQ_ACTIVE) {
543 if ((p->flags & PG_REFERENCED) == 0) {
544 p->act_count -= min(p->act_count, ACT_DECLINE);
545 if (!info->limit && (vm_pageout_algorithm || (p->act_count == 0))) {
984263bc 546 vm_page_protect(p, VM_PROT_NONE);
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547 vm_page_deactivate(p);
548 } else {
549 TAILQ_REMOVE(&vm_page_queues[PQ_ACTIVE].pl, p, pageq);
550 TAILQ_INSERT_TAIL(&vm_page_queues[PQ_ACTIVE].pl, p, pageq);
984263bc 551 }
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552 } else {
553 vm_page_activate(p);
554 vm_page_flag_clear(p, PG_REFERENCED);
555 if (p->act_count < (ACT_MAX - ACT_ADVANCE))
556 p->act_count += ACT_ADVANCE;
557 TAILQ_REMOVE(&vm_page_queues[PQ_ACTIVE].pl, p, pageq);
558 TAILQ_INSERT_TAIL(&vm_page_queues[PQ_ACTIVE].pl, p, pageq);
984263bc 559 }
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560 } else if (p->queue == PQ_INACTIVE) {
561 vm_page_protect(p, VM_PROT_NONE);
984263bc 562 }
1f804340 563 return(0);
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564}
565
566/*
567 * deactivate some number of pages in a map, try to do it fairly, but
568 * that is really hard to do.
569 */
570static void
57e43348 571vm_pageout_map_deactivate_pages(vm_map_t map, vm_pindex_t desired)
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572{
573 vm_map_entry_t tmpe;
574 vm_object_t obj, bigobj;
575 int nothingwired;
576
df4f70a6 577 if (lockmgr(&map->lock, LK_EXCLUSIVE | LK_NOWAIT)) {
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578 return;
579 }
580
581 bigobj = NULL;
582 nothingwired = TRUE;
583
584 /*
585 * first, search out the biggest object, and try to free pages from
586 * that.
587 */
588 tmpe = map->header.next;
589 while (tmpe != &map->header) {
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590 switch(tmpe->maptype) {
591 case VM_MAPTYPE_NORMAL:
592 case VM_MAPTYPE_VPAGETABLE:
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593 obj = tmpe->object.vm_object;
594 if ((obj != NULL) && (obj->shadow_count <= 1) &&
595 ((bigobj == NULL) ||
596 (bigobj->resident_page_count < obj->resident_page_count))) {
597 bigobj = obj;
598 }
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599 break;
600 default:
601 break;
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602 }
603 if (tmpe->wired_count > 0)
604 nothingwired = FALSE;
605 tmpe = tmpe->next;
606 }
607
608 if (bigobj)
609 vm_pageout_object_deactivate_pages(map, bigobj, desired, 0);
610
611 /*
612 * Next, hunt around for other pages to deactivate. We actually
613 * do this search sort of wrong -- .text first is not the best idea.
614 */
615 tmpe = map->header.next;
616 while (tmpe != &map->header) {
617 if (pmap_resident_count(vm_map_pmap(map)) <= desired)
618 break;
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619 switch(tmpe->maptype) {
620 case VM_MAPTYPE_NORMAL:
621 case VM_MAPTYPE_VPAGETABLE:
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622 obj = tmpe->object.vm_object;
623 if (obj)
624 vm_pageout_object_deactivate_pages(map, obj, desired, 0);
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625 break;
626 default:
627 break;
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628 }
629 tmpe = tmpe->next;
630 };
631
632 /*
633 * Remove all mappings if a process is swapped out, this will free page
634 * table pages.
635 */
636 if (desired == 0 && nothingwired)
637 pmap_remove(vm_map_pmap(map),
88181b08 638 VM_MIN_USER_ADDRESS, VM_MAX_USER_ADDRESS);
984263bc 639 vm_map_unlock(map);
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640}
641#endif
642
643/*
a11aaa81
MD
644 * Don't try to be fancy - being fancy can lead to vnode deadlocks. We
645 * only do it for OBJT_DEFAULT and OBJT_SWAP objects which we know can
646 * be trivially freed.
984263bc 647 */
984263bc
MD
648void
649vm_pageout_page_free(vm_page_t m) {
650 vm_object_t object = m->object;
651 int type = object->type;
652
653 if (type == OBJT_SWAP || type == OBJT_DEFAULT)
654 vm_object_reference(object);
655 vm_page_busy(m);
656 vm_page_protect(m, VM_PROT_NONE);
657 vm_page_free(m);
658 if (type == OBJT_SWAP || type == OBJT_DEFAULT)
659 vm_object_deallocate(object);
660}
661
662/*
663 * vm_pageout_scan does the dirty work for the pageout daemon.
664 */
8fa76237
MD
665
666struct vm_pageout_scan_info {
667 struct proc *bigproc;
668 vm_offset_t bigsize;
669};
670
671static int vm_pageout_scan_callback(struct proc *p, void *data);
672
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MD
673static void
674vm_pageout_scan(int pass)
675{
8fa76237 676 struct vm_pageout_scan_info info;
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MD
677 vm_page_t m, next;
678 struct vm_page marker;
679 int page_shortage, maxscan, pcount;
680 int addl_page_shortage, addl_page_shortage_init;
984263bc
MD
681 vm_object_t object;
682 int actcount;
683 int vnodes_skipped = 0;
684 int maxlaunder;
984263bc
MD
685
686 /*
687 * Do whatever cleanup that the pmap code can.
688 */
689 pmap_collect();
690
691 addl_page_shortage_init = vm_pageout_deficit;
692 vm_pageout_deficit = 0;
693
694 /*
695 * Calculate the number of pages we want to either free or move
696 * to the cache.
697 */
698 page_shortage = vm_paging_target() + addl_page_shortage_init;
699
700 /*
701 * Initialize our marker
702 */
703 bzero(&marker, sizeof(marker));
704 marker.flags = PG_BUSY | PG_FICTITIOUS | PG_MARKER;
705 marker.queue = PQ_INACTIVE;
706 marker.wire_count = 1;
707
708 /*
709 * Start scanning the inactive queue for pages we can move to the
710 * cache or free. The scan will stop when the target is reached or
711 * we have scanned the entire inactive queue. Note that m->act_count
712 * is not used to form decisions for the inactive queue, only for the
713 * active queue.
714 *
715 * maxlaunder limits the number of dirty pages we flush per scan.
716 * For most systems a smaller value (16 or 32) is more robust under
717 * extreme memory and disk pressure because any unnecessary writes
718 * to disk can result in extreme performance degredation. However,
719 * systems with excessive dirty pages (especially when MAP_NOSYNC is
720 * used) will die horribly with limited laundering. If the pageout
721 * daemon cannot clean enough pages in the first pass, we let it go
722 * all out in succeeding passes.
723 */
724 if ((maxlaunder = vm_max_launder) <= 1)
725 maxlaunder = 1;
726 if (pass)
727 maxlaunder = 10000;
728
06ecca5a 729 /*
5fd012e0
MD
730 * We will generally be in a critical section throughout the
731 * scan, but we can release it temporarily when we are sitting on a
732 * non-busy page without fear. this is required to prevent an
733 * interrupt from unbusying or freeing a page prior to our busy
734 * check, leaving us on the wrong queue or checking the wrong
735 * page.
06ecca5a 736 */
5fd012e0 737 crit_enter();
984263bc
MD
738rescan0:
739 addl_page_shortage = addl_page_shortage_init;
12e4aaff 740 maxscan = vmstats.v_inactive_count;
984263bc
MD
741 for (m = TAILQ_FIRST(&vm_page_queues[PQ_INACTIVE].pl);
742 m != NULL && maxscan-- > 0 && page_shortage > 0;
06ecca5a
MD
743 m = next
744 ) {
12e4aaff 745 mycpu->gd_cnt.v_pdpages++;
984263bc 746
06ecca5a
MD
747 /*
748 * Give interrupts a chance
749 */
5fd012e0
MD
750 crit_exit();
751 crit_enter();
984263bc 752
06ecca5a
MD
753 /*
754 * It's easier for some of the conditions below to just loop
755 * and catch queue changes here rather then check everywhere
756 * else.
757 */
758 if (m->queue != PQ_INACTIVE)
759 goto rescan0;
984263bc
MD
760 next = TAILQ_NEXT(m, pageq);
761
762 /*
763 * skip marker pages
764 */
765 if (m->flags & PG_MARKER)
766 continue;
767
768 /*
769 * A held page may be undergoing I/O, so skip it.
770 */
771 if (m->hold_count) {
984263bc
MD
772 TAILQ_REMOVE(&vm_page_queues[PQ_INACTIVE].pl, m, pageq);
773 TAILQ_INSERT_TAIL(&vm_page_queues[PQ_INACTIVE].pl, m, pageq);
984263bc
MD
774 addl_page_shortage++;
775 continue;
776 }
06ecca5a 777
984263bc
MD
778 /*
779 * Dont mess with busy pages, keep in the front of the
780 * queue, most likely are being paged out.
781 */
782 if (m->busy || (m->flags & PG_BUSY)) {
783 addl_page_shortage++;
784 continue;
785 }
786
984263bc 787 if (m->object->ref_count == 0) {
06ecca5a
MD
788 /*
789 * If the object is not being used, we ignore previous
790 * references.
791 */
984263bc
MD
792 vm_page_flag_clear(m, PG_REFERENCED);
793 pmap_clear_reference(m);
794
984263bc 795 } else if (((m->flags & PG_REFERENCED) == 0) &&
06ecca5a
MD
796 (actcount = pmap_ts_referenced(m))) {
797 /*
798 * Otherwise, if the page has been referenced while
799 * in the inactive queue, we bump the "activation
800 * count" upwards, making it less likely that the
801 * page will be added back to the inactive queue
802 * prematurely again. Here we check the page tables
803 * (or emulated bits, if any), given the upper level
804 * VM system not knowing anything about existing
805 * references.
806 */
984263bc
MD
807 vm_page_activate(m);
808 m->act_count += (actcount + ACT_ADVANCE);
809 continue;
810 }
811
812 /*
813 * If the upper level VM system knows about any page
814 * references, we activate the page. We also set the
815 * "activation count" higher than normal so that we will less
816 * likely place pages back onto the inactive queue again.
817 */
818 if ((m->flags & PG_REFERENCED) != 0) {
819 vm_page_flag_clear(m, PG_REFERENCED);
820 actcount = pmap_ts_referenced(m);
821 vm_page_activate(m);
822 m->act_count += (actcount + ACT_ADVANCE + 1);
823 continue;
824 }
825
826 /*
827 * If the upper level VM system doesn't know anything about
828 * the page being dirty, we have to check for it again. As
829 * far as the VM code knows, any partially dirty pages are
830 * fully dirty.
41a01a4d
MD
831 *
832 * Pages marked PG_WRITEABLE may be mapped into the user
833 * address space of a process running on another cpu. A
834 * user process (without holding the MP lock) running on
835 * another cpu may be able to touch the page while we are
836 * trying to remove it. To prevent this from occuring we
837 * must call pmap_remove_all() or otherwise make the page
838 * read-only. If the race occured pmap_remove_all() is
839 * responsible for setting m->dirty.
984263bc
MD
840 */
841 if (m->dirty == 0) {
842 vm_page_test_dirty(m);
41a01a4d
MD
843#if 0
844 if (m->dirty == 0 && (m->flags & PG_WRITEABLE) != 0)
845 pmap_remove_all(m);
846#endif
984263bc
MD
847 } else {
848 vm_page_dirty(m);
849 }
850
984263bc 851 if (m->valid == 0) {
41a01a4d
MD
852 /*
853 * Invalid pages can be easily freed
854 */
984263bc 855 vm_pageout_page_free(m);
12e4aaff 856 mycpu->gd_cnt.v_dfree++;
984263bc 857 --page_shortage;
984263bc
MD
858 } else if (m->dirty == 0) {
859 /*
41a01a4d
MD
860 * Clean pages can be placed onto the cache queue.
861 * This effectively frees them.
984263bc
MD
862 */
863 vm_page_cache(m);
864 --page_shortage;
865 } else if ((m->flags & PG_WINATCFLS) == 0 && pass == 0) {
866 /*
867 * Dirty pages need to be paged out, but flushing
868 * a page is extremely expensive verses freeing
869 * a clean page. Rather then artificially limiting
870 * the number of pages we can flush, we instead give
871 * dirty pages extra priority on the inactive queue
872 * by forcing them to be cycled through the queue
873 * twice before being flushed, after which the
874 * (now clean) page will cycle through once more
875 * before being freed. This significantly extends
876 * the thrash point for a heavily loaded machine.
877 */
984263bc
MD
878 vm_page_flag_set(m, PG_WINATCFLS);
879 TAILQ_REMOVE(&vm_page_queues[PQ_INACTIVE].pl, m, pageq);
880 TAILQ_INSERT_TAIL(&vm_page_queues[PQ_INACTIVE].pl, m, pageq);
984263bc
MD
881 } else if (maxlaunder > 0) {
882 /*
883 * We always want to try to flush some dirty pages if
884 * we encounter them, to keep the system stable.
885 * Normally this number is small, but under extreme
886 * pressure where there are insufficient clean pages
887 * on the inactive queue, we may have to go all out.
888 */
889 int swap_pageouts_ok;
890 struct vnode *vp = NULL;
891
892 object = m->object;
893
894 if ((object->type != OBJT_SWAP) && (object->type != OBJT_DEFAULT)) {
895 swap_pageouts_ok = 1;
896 } else {
897 swap_pageouts_ok = !(defer_swap_pageouts || disable_swap_pageouts);
898 swap_pageouts_ok |= (!disable_swap_pageouts && defer_swap_pageouts &&
899 vm_page_count_min());
900
901 }
902
903 /*
904 * We don't bother paging objects that are "dead".
905 * Those objects are in a "rundown" state.
906 */
907 if (!swap_pageouts_ok || (object->flags & OBJ_DEAD)) {
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MD
908 TAILQ_REMOVE(&vm_page_queues[PQ_INACTIVE].pl, m, pageq);
909 TAILQ_INSERT_TAIL(&vm_page_queues[PQ_INACTIVE].pl, m, pageq);
984263bc
MD
910 continue;
911 }
912
913 /*
914 * The object is already known NOT to be dead. It
915 * is possible for the vget() to block the whole
916 * pageout daemon, but the new low-memory handling
917 * code should prevent it.
918 *
919 * The previous code skipped locked vnodes and, worse,
920 * reordered pages in the queue. This results in
921 * completely non-deterministic operation because,
922 * quite often, a vm_fault has initiated an I/O and
923 * is holding a locked vnode at just the point where
924 * the pageout daemon is woken up.
925 *
926 * We can't wait forever for the vnode lock, we might
927 * deadlock due to a vn_read() getting stuck in
928 * vm_wait while holding this vnode. We skip the
929 * vnode if we can't get it in a reasonable amount
930 * of time.
931 */
932
933 if (object->type == OBJT_VNODE) {
934 vp = object->handle;
935
87de5057 936 if (vget(vp, LK_EXCLUSIVE|LK_NOOBJ|LK_TIMELOCK)) {
984263bc
MD
937 ++pageout_lock_miss;
938 if (object->flags & OBJ_MIGHTBEDIRTY)
939 vnodes_skipped++;
940 continue;
941 }
942
943 /*
944 * The page might have been moved to another
945 * queue during potential blocking in vget()
946 * above. The page might have been freed and
947 * reused for another vnode. The object might
948 * have been reused for another vnode.
949 */
950 if (m->queue != PQ_INACTIVE ||
951 m->object != object ||
952 object->handle != vp) {
953 if (object->flags & OBJ_MIGHTBEDIRTY)
954 vnodes_skipped++;
955 vput(vp);
956 continue;
957 }
958
959 /*
960 * The page may have been busied during the
961 * blocking in vput(); We don't move the
962 * page back onto the end of the queue so that
963 * statistics are more correct if we don't.
964 */
965 if (m->busy || (m->flags & PG_BUSY)) {
966 vput(vp);
967 continue;
968 }
969
970 /*
971 * If the page has become held it might
972 * be undergoing I/O, so skip it
973 */
974 if (m->hold_count) {
984263bc
MD
975 TAILQ_REMOVE(&vm_page_queues[PQ_INACTIVE].pl, m, pageq);
976 TAILQ_INSERT_TAIL(&vm_page_queues[PQ_INACTIVE].pl, m, pageq);
984263bc
MD
977 if (object->flags & OBJ_MIGHTBEDIRTY)
978 vnodes_skipped++;
979 vput(vp);
980 continue;
981 }
982 }
983
984 /*
985 * If a page is dirty, then it is either being washed
986 * (but not yet cleaned) or it is still in the
987 * laundry. If it is still in the laundry, then we
988 * start the cleaning operation.
989 *
990 * This operation may cluster, invalidating the 'next'
991 * pointer. To prevent an inordinate number of
992 * restarts we use our marker to remember our place.
993 *
994 * decrement page_shortage on success to account for
995 * the (future) cleaned page. Otherwise we could wind
996 * up laundering or cleaning too many pages.
997 */
984263bc 998 TAILQ_INSERT_AFTER(&vm_page_queues[PQ_INACTIVE].pl, m, &marker, pageq);
984263bc
MD
999 if (vm_pageout_clean(m) != 0) {
1000 --page_shortage;
1001 --maxlaunder;
1002 }
984263bc
MD
1003 next = TAILQ_NEXT(&marker, pageq);
1004 TAILQ_REMOVE(&vm_page_queues[PQ_INACTIVE].pl, &marker, pageq);
984263bc
MD
1005 if (vp != NULL)
1006 vput(vp);
1007 }
1008 }
1009
1010 /*
1011 * Compute the number of pages we want to try to move from the
1012 * active queue to the inactive queue.
1013 */
1014 page_shortage = vm_paging_target() +
12e4aaff 1015 vmstats.v_inactive_target - vmstats.v_inactive_count;
984263bc
MD
1016 page_shortage += addl_page_shortage;
1017
1018 /*
1019 * Scan the active queue for things we can deactivate. We nominally
1020 * track the per-page activity counter and use it to locate
1021 * deactivation candidates.
06ecca5a 1022 *
5fd012e0 1023 * NOTE: we are still in a critical section.
984263bc 1024 */
12e4aaff 1025 pcount = vmstats.v_active_count;
984263bc
MD
1026 m = TAILQ_FIRST(&vm_page_queues[PQ_ACTIVE].pl);
1027
1028 while ((m != NULL) && (pcount-- > 0) && (page_shortage > 0)) {
06ecca5a
MD
1029 /*
1030 * Give interrupts a chance.
1031 */
5fd012e0
MD
1032 crit_exit();
1033 crit_enter();
984263bc
MD
1034
1035 /*
06ecca5a 1036 * If the page was ripped out from under us, just stop.
984263bc 1037 */
06ecca5a 1038 if (m->queue != PQ_ACTIVE)
984263bc 1039 break;
984263bc 1040 next = TAILQ_NEXT(m, pageq);
06ecca5a 1041
984263bc
MD
1042 /*
1043 * Don't deactivate pages that are busy.
1044 */
1045 if ((m->busy != 0) ||
1046 (m->flags & PG_BUSY) ||
1047 (m->hold_count != 0)) {
984263bc
MD
1048 TAILQ_REMOVE(&vm_page_queues[PQ_ACTIVE].pl, m, pageq);
1049 TAILQ_INSERT_TAIL(&vm_page_queues[PQ_ACTIVE].pl, m, pageq);
984263bc
MD
1050 m = next;
1051 continue;
1052 }
1053
1054 /*
1055 * The count for pagedaemon pages is done after checking the
1056 * page for eligibility...
1057 */
12e4aaff 1058 mycpu->gd_cnt.v_pdpages++;
984263bc
MD
1059
1060 /*
1061 * Check to see "how much" the page has been used.
1062 */
1063 actcount = 0;
1064 if (m->object->ref_count != 0) {
1065 if (m->flags & PG_REFERENCED) {
1066 actcount += 1;
1067 }
1068 actcount += pmap_ts_referenced(m);
1069 if (actcount) {
1070 m->act_count += ACT_ADVANCE + actcount;
1071 if (m->act_count > ACT_MAX)
1072 m->act_count = ACT_MAX;
1073 }
1074 }
1075
1076 /*
1077 * Since we have "tested" this bit, we need to clear it now.
1078 */
1079 vm_page_flag_clear(m, PG_REFERENCED);
1080
1081 /*
1082 * Only if an object is currently being used, do we use the
1083 * page activation count stats.
1084 */
1085 if (actcount && (m->object->ref_count != 0)) {
984263bc
MD
1086 TAILQ_REMOVE(&vm_page_queues[PQ_ACTIVE].pl, m, pageq);
1087 TAILQ_INSERT_TAIL(&vm_page_queues[PQ_ACTIVE].pl, m, pageq);
984263bc
MD
1088 } else {
1089 m->act_count -= min(m->act_count, ACT_DECLINE);
1090 if (vm_pageout_algorithm ||
1091 m->object->ref_count == 0 ||
b5ccee96 1092 m->act_count < pass) {
984263bc
MD
1093 page_shortage--;
1094 if (m->object->ref_count == 0) {
1095 vm_page_protect(m, VM_PROT_NONE);
1096 if (m->dirty == 0)
1097 vm_page_cache(m);
1098 else
1099 vm_page_deactivate(m);
1100 } else {
1101 vm_page_deactivate(m);
1102 }
1103 } else {
984263bc
MD
1104 TAILQ_REMOVE(&vm_page_queues[PQ_ACTIVE].pl, m, pageq);
1105 TAILQ_INSERT_TAIL(&vm_page_queues[PQ_ACTIVE].pl, m, pageq);
984263bc
MD
1106 }
1107 }
1108 m = next;
1109 }
1110
984263bc
MD
1111 /*
1112 * We try to maintain some *really* free pages, this allows interrupt
1113 * code to be guaranteed space. Since both cache and free queues
1114 * are considered basically 'free', moving pages from cache to free
1115 * does not effect other calculations.
06ecca5a 1116 *
5fd012e0 1117 * NOTE: we are still in a critical section.
984263bc
MD
1118 */
1119
12e4aaff 1120 while (vmstats.v_free_count < vmstats.v_free_reserved) {
984263bc
MD
1121 static int cache_rover = 0;
1122 m = vm_page_list_find(PQ_CACHE, cache_rover, FALSE);
1123 if (!m)
1124 break;
1125 if ((m->flags & (PG_BUSY|PG_UNMANAGED)) ||
1126 m->busy ||
1127 m->hold_count ||
1128 m->wire_count) {
1129#ifdef INVARIANTS
086c1d7e 1130 kprintf("Warning: busy page %p found in cache\n", m);
984263bc
MD
1131#endif
1132 vm_page_deactivate(m);
1133 continue;
1134 }
1135 cache_rover = (cache_rover + PQ_PRIME2) & PQ_L2_MASK;
1136 vm_pageout_page_free(m);
12e4aaff 1137 mycpu->gd_cnt.v_dfree++;
984263bc 1138 }
06ecca5a 1139
5fd012e0 1140 crit_exit();
984263bc
MD
1141
1142#if !defined(NO_SWAPPING)
1143 /*
1144 * Idle process swapout -- run once per second.
1145 */
1146 if (vm_swap_idle_enabled) {
1147 static long lsec;
1148 if (time_second != lsec) {
1149 vm_pageout_req_swapout |= VM_SWAP_IDLE;
1150 vm_req_vmdaemon();
1151 lsec = time_second;
1152 }
1153 }
1154#endif
1155
1156 /*
1157 * If we didn't get enough free pages, and we have skipped a vnode
1158 * in a writeable object, wakeup the sync daemon. And kick swapout
1159 * if we did not get enough free pages.
1160 */
1161 if (vm_paging_target() > 0) {
1162 if (vnodes_skipped && vm_page_count_min())
418ff780 1163 speedup_syncer();
984263bc
MD
1164#if !defined(NO_SWAPPING)
1165 if (vm_swap_enabled && vm_page_count_target()) {
1166 vm_req_vmdaemon();
1167 vm_pageout_req_swapout |= VM_SWAP_NORMAL;
1168 }
1169#endif
1170 }
1171
1172 /*
1173 * If we are out of swap and were not able to reach our paging
1174 * target, kill the largest process.
1175 */
1176 if ((vm_swap_size < 64 && vm_page_count_min()) ||
1177 (swap_pager_full && vm_paging_target() > 0)) {
1178#if 0
1179 if ((vm_swap_size < 64 || swap_pager_full) && vm_page_count_min()) {
1180#endif
8fa76237
MD
1181 info.bigproc = NULL;
1182 info.bigsize = 0;
1183 allproc_scan(vm_pageout_scan_callback, &info);
1184 if (info.bigproc != NULL) {
1185 killproc(info.bigproc, "out of swap space");
1186 info.bigproc->p_nice = PRIO_MIN;
08f2f1bb
SS
1187 info.bigproc->p_usched->resetpriority(
1188 FIRST_LWP_IN_PROC(info.bigproc));
12e4aaff 1189 wakeup(&vmstats.v_free_count);
8fa76237 1190 PRELE(info.bigproc);
984263bc
MD
1191 }
1192 }
1193}
1194
8fa76237
MD
1195static int
1196vm_pageout_scan_callback(struct proc *p, void *data)
1197{
1198 struct vm_pageout_scan_info *info = data;
1199 vm_offset_t size;
1200
1201 /*
1202 * if this is a system process, skip it
1203 */
1204 if ((p->p_flag & P_SYSTEM) || (p->p_pid == 1) ||
1205 ((p->p_pid < 48) && (vm_swap_size != 0))) {
1206 return (0);
1207 }
1208
1209 /*
1210 * if the process is in a non-running type state,
1211 * don't touch it.
1212 */
1213 if (p->p_stat != SRUN && p->p_stat != SSLEEP) {
1214 return (0);
1215 }
1216
1217 /*
1218 * get the process size
1219 */
1220 size = vmspace_resident_count(p->p_vmspace) +
1221 vmspace_swap_count(p->p_vmspace);
1222
1223 /*
1224 * If the this process is bigger than the biggest one
1225 * remember it.
1226 */
1227 if (size > info->bigsize) {
1228 if (info->bigproc)
1229 PRELE(info->bigproc);
1230 PHOLD(p);
1231 info->bigproc = p;
1232 info->bigsize = size;
1233 }
1234 return(0);
1235}
1236
984263bc
MD
1237/*
1238 * This routine tries to maintain the pseudo LRU active queue,
1239 * so that during long periods of time where there is no paging,
1240 * that some statistic accumulation still occurs. This code
1241 * helps the situation where paging just starts to occur.
1242 */
1243static void
57e43348 1244vm_pageout_page_stats(void)
984263bc 1245{
984263bc
MD
1246 vm_page_t m,next;
1247 int pcount,tpcount; /* Number of pages to check */
1248 static int fullintervalcount = 0;
1249 int page_shortage;
984263bc
MD
1250
1251 page_shortage =
12e4aaff
MD
1252 (vmstats.v_inactive_target + vmstats.v_cache_max + vmstats.v_free_min) -
1253 (vmstats.v_free_count + vmstats.v_inactive_count + vmstats.v_cache_count);
984263bc
MD
1254
1255 if (page_shortage <= 0)
1256 return;
1257
5fd012e0 1258 crit_enter();
984263bc 1259
12e4aaff 1260 pcount = vmstats.v_active_count;
984263bc
MD
1261 fullintervalcount += vm_pageout_stats_interval;
1262 if (fullintervalcount < vm_pageout_full_stats_interval) {
12e4aaff 1263 tpcount = (vm_pageout_stats_max * vmstats.v_active_count) / vmstats.v_page_count;
984263bc
MD
1264 if (pcount > tpcount)
1265 pcount = tpcount;
1266 } else {
1267 fullintervalcount = 0;
1268 }
1269
1270 m = TAILQ_FIRST(&vm_page_queues[PQ_ACTIVE].pl);
1271 while ((m != NULL) && (pcount-- > 0)) {
1272 int actcount;
1273
1274 if (m->queue != PQ_ACTIVE) {
1275 break;
1276 }
1277
1278 next = TAILQ_NEXT(m, pageq);
1279 /*
1280 * Don't deactivate pages that are busy.
1281 */
1282 if ((m->busy != 0) ||
1283 (m->flags & PG_BUSY) ||
1284 (m->hold_count != 0)) {
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1285 TAILQ_REMOVE(&vm_page_queues[PQ_ACTIVE].pl, m, pageq);
1286 TAILQ_INSERT_TAIL(&vm_page_queues[PQ_ACTIVE].pl, m, pageq);
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1287 m = next;
1288 continue;
1289 }
1290
1291 actcount = 0;
1292 if (m->flags & PG_REFERENCED) {
1293 vm_page_flag_clear(m, PG_REFERENCED);
1294 actcount += 1;
1295 }
1296
1297 actcount += pmap_ts_referenced(m);
1298 if (actcount) {
1299 m->act_count += ACT_ADVANCE + actcount;
1300 if (m->act_count > ACT_MAX)
1301 m->act_count = ACT_MAX;
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1302 TAILQ_REMOVE(&vm_page_queues[PQ_ACTIVE].pl, m, pageq);
1303 TAILQ_INSERT_TAIL(&vm_page_queues[PQ_ACTIVE].pl, m, pageq);
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1304 } else {
1305 if (m->act_count == 0) {
1306 /*
1307 * We turn off page access, so that we have
1308 * more accurate RSS stats. We don't do this
1309 * in the normal page deactivation when the
1310 * system is loaded VM wise, because the
1311 * cost of the large number of page protect
1312 * operations would be higher than the value
1313 * of doing the operation.
1314 */
1315 vm_page_protect(m, VM_PROT_NONE);
1316 vm_page_deactivate(m);
1317 } else {
1318 m->act_count -= min(m->act_count, ACT_DECLINE);
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1319 TAILQ_REMOVE(&vm_page_queues[PQ_ACTIVE].pl, m, pageq);
1320 TAILQ_INSERT_TAIL(&vm_page_queues[PQ_ACTIVE].pl, m, pageq);
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1321 }
1322 }
1323
1324 m = next;
1325 }
5fd012e0 1326 crit_exit();
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1327}
1328
1329static int
57e43348 1330vm_pageout_free_page_calc(vm_size_t count)
984263bc 1331{
12e4aaff 1332 if (count < vmstats.v_page_count)
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1333 return 0;
1334 /*
1335 * free_reserved needs to include enough for the largest swap pager
1336 * structures plus enough for any pv_entry structs when paging.
1337 */
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1338 if (vmstats.v_page_count > 1024)
1339 vmstats.v_free_min = 4 + (vmstats.v_page_count - 1024) / 200;
984263bc 1340 else
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1341 vmstats.v_free_min = 4;
1342 vmstats.v_pageout_free_min = (2*MAXBSIZE)/PAGE_SIZE +
1343 vmstats.v_interrupt_free_min;
1344 vmstats.v_free_reserved = vm_pageout_page_count +
1345 vmstats.v_pageout_free_min + (count / 768) + PQ_L2_SIZE;
1346 vmstats.v_free_severe = vmstats.v_free_min / 2;
1347 vmstats.v_free_min += vmstats.v_free_reserved;
1348 vmstats.v_free_severe += vmstats.v_free_reserved;
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1349 return 1;
1350}
1351
1352
1353/*
1354 * vm_pageout is the high level pageout daemon.
1355 */
1356static void
57e43348 1357vm_pageout(void)
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1358{
1359 int pass;
1360
1361 /*
1362 * Initialize some paging parameters.
1363 */
1364
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1365 vmstats.v_interrupt_free_min = 2;
1366 if (vmstats.v_page_count < 2000)
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1367 vm_pageout_page_count = 8;
1368
12e4aaff 1369 vm_pageout_free_page_calc(vmstats.v_page_count);
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1370 /*
1371 * v_free_target and v_cache_min control pageout hysteresis. Note
1372 * that these are more a measure of the VM cache queue hysteresis
1373 * then the VM free queue. Specifically, v_free_target is the
1374 * high water mark (free+cache pages).
1375 *
1376 * v_free_reserved + v_cache_min (mostly means v_cache_min) is the
1377 * low water mark, while v_free_min is the stop. v_cache_min must
1378 * be big enough to handle memory needs while the pageout daemon
1379 * is signalled and run to free more pages.
1380 */
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1381 if (vmstats.v_free_count > 6144)
1382 vmstats.v_free_target = 4 * vmstats.v_free_min + vmstats.v_free_reserved;
984263bc 1383 else
12e4aaff 1384 vmstats.v_free_target = 2 * vmstats.v_free_min + vmstats.v_free_reserved;
984263bc 1385
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1386 if (vmstats.v_free_count > 2048) {
1387 vmstats.v_cache_min = vmstats.v_free_target;
1388 vmstats.v_cache_max = 2 * vmstats.v_cache_min;
1389 vmstats.v_inactive_target = (3 * vmstats.v_free_target) / 2;
984263bc 1390 } else {
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1391 vmstats.v_cache_min = 0;
1392 vmstats.v_cache_max = 0;
1393 vmstats.v_inactive_target = vmstats.v_free_count / 4;
984263bc 1394 }
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1395 if (vmstats.v_inactive_target > vmstats.v_free_count / 3)
1396 vmstats.v_inactive_target = vmstats.v_free_count / 3;
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1397
1398 /* XXX does not really belong here */
1399 if (vm_page_max_wired == 0)
12e4aaff 1400 vm_page_max_wired = vmstats.v_free_count / 3;
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1401
1402 if (vm_pageout_stats_max == 0)
12e4aaff 1403 vm_pageout_stats_max = vmstats.v_free_target;
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1404
1405 /*
1406 * Set interval in seconds for stats scan.
1407 */
1408 if (vm_pageout_stats_interval == 0)
1409 vm_pageout_stats_interval = 5;
1410 if (vm_pageout_full_stats_interval == 0)
1411 vm_pageout_full_stats_interval = vm_pageout_stats_interval * 4;
1412
1413
1414 /*
1415 * Set maximum free per pass
1416 */
1417 if (vm_pageout_stats_free_max == 0)
1418 vm_pageout_stats_free_max = 5;
1419
1420 swap_pager_swap_init();
1421 pass = 0;
1422 /*
1423 * The pageout daemon is never done, so loop forever.
1424 */
1425 while (TRUE) {
1426 int error;
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1427
1428 /*
1429 * If we have enough free memory, wakeup waiters. Do
1430 * not clear vm_pages_needed until we reach our target,
1431 * otherwise we may be woken up over and over again and
1432 * waste a lot of cpu.
1433 */
5fd012e0 1434 crit_enter();
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1435 if (vm_pages_needed && !vm_page_count_min()) {
1436 if (vm_paging_needed() <= 0)
1437 vm_pages_needed = 0;
12e4aaff 1438 wakeup(&vmstats.v_free_count);
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1439 }
1440 if (vm_pages_needed) {
1441 /*
1442 * Still not done, take a second pass without waiting
1443 * (unlimited dirty cleaning), otherwise sleep a bit
1444 * and try again.
1445 */
1446 ++pass;
1447 if (pass > 1)
377d4740 1448 tsleep(&vm_pages_needed, 0, "psleep", hz/2);
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1449 } else {
1450 /*
1451 * Good enough, sleep & handle stats. Prime the pass
1452 * for the next run.
1453 */
1454 if (pass > 1)
1455 pass = 1;
1456 else
1457 pass = 0;
1458 error = tsleep(&vm_pages_needed,
377d4740 1459 0, "psleep", vm_pageout_stats_interval * hz);
984263bc 1460 if (error && !vm_pages_needed) {
5fd012e0 1461 crit_exit();
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1462 pass = 0;
1463 vm_pageout_page_stats();
1464 continue;
1465 }
1466 }
1467
1468 if (vm_pages_needed)
12e4aaff 1469 mycpu->gd_cnt.v_pdwakeups++;
5fd012e0 1470 crit_exit();
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1471 vm_pageout_scan(pass);
1472 vm_pageout_deficit = 0;
1473 }
1474}
1475
1476void
57e43348 1477pagedaemon_wakeup(void)
984263bc 1478{
bc6dffab 1479 if (!vm_pages_needed && curthread != pagethread) {
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1480 vm_pages_needed++;
1481 wakeup(&vm_pages_needed);
1482 }
1483}
1484
1485#if !defined(NO_SWAPPING)
1486static void
57e43348 1487vm_req_vmdaemon(void)
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1488{
1489 static int lastrun = 0;
1490
1491 if ((ticks > (lastrun + hz)) || (ticks < lastrun)) {
1492 wakeup(&vm_daemon_needed);
1493 lastrun = ticks;
1494 }
1495}
1496
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1497static int vm_daemon_callback(struct proc *p, void *data __unused);
1498
984263bc 1499static void
57e43348 1500vm_daemon(void)
984263bc 1501{
984263bc 1502 while (TRUE) {
377d4740 1503 tsleep(&vm_daemon_needed, 0, "psleep", 0);
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1504 if (vm_pageout_req_swapout) {
1505 swapout_procs(vm_pageout_req_swapout);
1506 vm_pageout_req_swapout = 0;
1507 }
1508 /*
1509 * scan the processes for exceeding their rlimits or if
1510 * process is swapped out -- deactivate pages
1511 */
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1512 allproc_scan(vm_daemon_callback, NULL);
1513 }
1514}
984263bc 1515
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1516static int
1517vm_daemon_callback(struct proc *p, void *data __unused)
1518{
1519 vm_pindex_t limit, size;
984263bc 1520
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1521 /*
1522 * if this is a system process or if we have already
1523 * looked at this process, skip it.
1524 */
1525 if (p->p_flag & (P_SYSTEM | P_WEXIT))
1526 return (0);
984263bc 1527
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1528 /*
1529 * if the process is in a non-running type state,
1530 * don't touch it.
1531 */
1532 if (p->p_stat != SRUN && p->p_stat != SSLEEP)
1533 return (0);
984263bc 1534
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1535 /*
1536 * get a limit
1537 */
1538 limit = OFF_TO_IDX(qmin(p->p_rlimit[RLIMIT_RSS].rlim_cur,
1539 p->p_rlimit[RLIMIT_RSS].rlim_max));
1540
1541 /*
1542 * let processes that are swapped out really be
1543 * swapped out. Set the limit to nothing to get as
1544 * many pages out to swap as possible.
1545 */
1546 if (p->p_flag & P_SWAPPEDOUT)
1547 limit = 0;
1548
1549 size = vmspace_resident_count(p->p_vmspace);
1550 if (limit >= 0 && size >= limit) {
1551 vm_pageout_map_deactivate_pages(
1552 &p->p_vmspace->vm_map, limit);
984263bc 1553 }
8fa76237 1554 return (0);
984263bc 1555}
8fa76237 1556
984263bc 1557#endif