HAMMER utilities: feature add.
[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 $
95813af0 69 * $DragonFly: src/sys/vm/vm_pageout.c,v 1.32 2007/03/20 00:54:26 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,
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 648void
95813af0
MD
649vm_pageout_page_free(vm_page_t m)
650{
984263bc
MD
651 vm_object_t object = m->object;
652 int type = object->type;
653
654 if (type == OBJT_SWAP || type == OBJT_DEFAULT)
655 vm_object_reference(object);
656 vm_page_busy(m);
657 vm_page_protect(m, VM_PROT_NONE);
658 vm_page_free(m);
659 if (type == OBJT_SWAP || type == OBJT_DEFAULT)
660 vm_object_deallocate(object);
661}
662
663/*
664 * vm_pageout_scan does the dirty work for the pageout daemon.
665 */
8fa76237
MD
666
667struct vm_pageout_scan_info {
668 struct proc *bigproc;
669 vm_offset_t bigsize;
670};
671
672static int vm_pageout_scan_callback(struct proc *p, void *data);
673
984263bc
MD
674static void
675vm_pageout_scan(int pass)
676{
8fa76237 677 struct vm_pageout_scan_info info;
984263bc
MD
678 vm_page_t m, next;
679 struct vm_page marker;
680 int page_shortage, maxscan, pcount;
681 int addl_page_shortage, addl_page_shortage_init;
984263bc
MD
682 vm_object_t object;
683 int actcount;
684 int vnodes_skipped = 0;
685 int maxlaunder;
984263bc
MD
686
687 /*
688 * Do whatever cleanup that the pmap code can.
689 */
690 pmap_collect();
691
692 addl_page_shortage_init = vm_pageout_deficit;
693 vm_pageout_deficit = 0;
694
695 /*
696 * Calculate the number of pages we want to either free or move
697 * to the cache.
698 */
699 page_shortage = vm_paging_target() + addl_page_shortage_init;
700
701 /*
702 * Initialize our marker
703 */
704 bzero(&marker, sizeof(marker));
705 marker.flags = PG_BUSY | PG_FICTITIOUS | PG_MARKER;
706 marker.queue = PQ_INACTIVE;
707 marker.wire_count = 1;
708
709 /*
710 * Start scanning the inactive queue for pages we can move to the
711 * cache or free. The scan will stop when the target is reached or
712 * we have scanned the entire inactive queue. Note that m->act_count
713 * is not used to form decisions for the inactive queue, only for the
714 * active queue.
715 *
716 * maxlaunder limits the number of dirty pages we flush per scan.
717 * For most systems a smaller value (16 or 32) is more robust under
718 * extreme memory and disk pressure because any unnecessary writes
719 * to disk can result in extreme performance degredation. However,
720 * systems with excessive dirty pages (especially when MAP_NOSYNC is
721 * used) will die horribly with limited laundering. If the pageout
722 * daemon cannot clean enough pages in the first pass, we let it go
723 * all out in succeeding passes.
724 */
725 if ((maxlaunder = vm_max_launder) <= 1)
726 maxlaunder = 1;
727 if (pass)
728 maxlaunder = 10000;
729
06ecca5a 730 /*
5fd012e0
MD
731 * We will generally be in a critical section throughout the
732 * scan, but we can release it temporarily when we are sitting on a
733 * non-busy page without fear. this is required to prevent an
734 * interrupt from unbusying or freeing a page prior to our busy
735 * check, leaving us on the wrong queue or checking the wrong
736 * page.
06ecca5a 737 */
5fd012e0 738 crit_enter();
984263bc
MD
739rescan0:
740 addl_page_shortage = addl_page_shortage_init;
12e4aaff 741 maxscan = vmstats.v_inactive_count;
984263bc
MD
742 for (m = TAILQ_FIRST(&vm_page_queues[PQ_INACTIVE].pl);
743 m != NULL && maxscan-- > 0 && page_shortage > 0;
06ecca5a
MD
744 m = next
745 ) {
12e4aaff 746 mycpu->gd_cnt.v_pdpages++;
984263bc 747
06ecca5a
MD
748 /*
749 * Give interrupts a chance
750 */
5fd012e0
MD
751 crit_exit();
752 crit_enter();
984263bc 753
06ecca5a
MD
754 /*
755 * It's easier for some of the conditions below to just loop
756 * and catch queue changes here rather then check everywhere
757 * else.
758 */
759 if (m->queue != PQ_INACTIVE)
760 goto rescan0;
984263bc
MD
761 next = TAILQ_NEXT(m, pageq);
762
763 /*
764 * skip marker pages
765 */
766 if (m->flags & PG_MARKER)
767 continue;
768
769 /*
770 * A held page may be undergoing I/O, so skip it.
771 */
772 if (m->hold_count) {
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MD
773 TAILQ_REMOVE(&vm_page_queues[PQ_INACTIVE].pl, m, pageq);
774 TAILQ_INSERT_TAIL(&vm_page_queues[PQ_INACTIVE].pl, m, pageq);
984263bc
MD
775 addl_page_shortage++;
776 continue;
777 }
06ecca5a 778
984263bc
MD
779 /*
780 * Dont mess with busy pages, keep in the front of the
781 * queue, most likely are being paged out.
782 */
783 if (m->busy || (m->flags & PG_BUSY)) {
784 addl_page_shortage++;
785 continue;
786 }
787
984263bc 788 if (m->object->ref_count == 0) {
06ecca5a
MD
789 /*
790 * If the object is not being used, we ignore previous
791 * references.
792 */
984263bc
MD
793 vm_page_flag_clear(m, PG_REFERENCED);
794 pmap_clear_reference(m);
795
984263bc 796 } else if (((m->flags & PG_REFERENCED) == 0) &&
06ecca5a
MD
797 (actcount = pmap_ts_referenced(m))) {
798 /*
799 * Otherwise, if the page has been referenced while
800 * in the inactive queue, we bump the "activation
801 * count" upwards, making it less likely that the
802 * page will be added back to the inactive queue
803 * prematurely again. Here we check the page tables
804 * (or emulated bits, if any), given the upper level
805 * VM system not knowing anything about existing
806 * references.
807 */
984263bc
MD
808 vm_page_activate(m);
809 m->act_count += (actcount + ACT_ADVANCE);
810 continue;
811 }
812
813 /*
814 * If the upper level VM system knows about any page
815 * references, we activate the page. We also set the
816 * "activation count" higher than normal so that we will less
817 * likely place pages back onto the inactive queue again.
818 */
819 if ((m->flags & PG_REFERENCED) != 0) {
820 vm_page_flag_clear(m, PG_REFERENCED);
821 actcount = pmap_ts_referenced(m);
822 vm_page_activate(m);
823 m->act_count += (actcount + ACT_ADVANCE + 1);
824 continue;
825 }
826
827 /*
828 * If the upper level VM system doesn't know anything about
829 * the page being dirty, we have to check for it again. As
830 * far as the VM code knows, any partially dirty pages are
831 * fully dirty.
41a01a4d
MD
832 *
833 * Pages marked PG_WRITEABLE may be mapped into the user
834 * address space of a process running on another cpu. A
835 * user process (without holding the MP lock) running on
836 * another cpu may be able to touch the page while we are
837 * trying to remove it. To prevent this from occuring we
838 * must call pmap_remove_all() or otherwise make the page
839 * read-only. If the race occured pmap_remove_all() is
840 * responsible for setting m->dirty.
984263bc
MD
841 */
842 if (m->dirty == 0) {
843 vm_page_test_dirty(m);
41a01a4d
MD
844#if 0
845 if (m->dirty == 0 && (m->flags & PG_WRITEABLE) != 0)
846 pmap_remove_all(m);
847#endif
984263bc
MD
848 } else {
849 vm_page_dirty(m);
850 }
851
984263bc 852 if (m->valid == 0) {
41a01a4d
MD
853 /*
854 * Invalid pages can be easily freed
855 */
984263bc 856 vm_pageout_page_free(m);
12e4aaff 857 mycpu->gd_cnt.v_dfree++;
984263bc 858 --page_shortage;
984263bc
MD
859 } else if (m->dirty == 0) {
860 /*
41a01a4d
MD
861 * Clean pages can be placed onto the cache queue.
862 * This effectively frees them.
984263bc
MD
863 */
864 vm_page_cache(m);
865 --page_shortage;
866 } else if ((m->flags & PG_WINATCFLS) == 0 && pass == 0) {
867 /*
868 * Dirty pages need to be paged out, but flushing
869 * a page is extremely expensive verses freeing
870 * a clean page. Rather then artificially limiting
871 * the number of pages we can flush, we instead give
872 * dirty pages extra priority on the inactive queue
873 * by forcing them to be cycled through the queue
874 * twice before being flushed, after which the
875 * (now clean) page will cycle through once more
876 * before being freed. This significantly extends
877 * the thrash point for a heavily loaded machine.
878 */
984263bc
MD
879 vm_page_flag_set(m, PG_WINATCFLS);
880 TAILQ_REMOVE(&vm_page_queues[PQ_INACTIVE].pl, m, pageq);
881 TAILQ_INSERT_TAIL(&vm_page_queues[PQ_INACTIVE].pl, m, pageq);
984263bc
MD
882 } else if (maxlaunder > 0) {
883 /*
884 * We always want to try to flush some dirty pages if
885 * we encounter them, to keep the system stable.
886 * Normally this number is small, but under extreme
887 * pressure where there are insufficient clean pages
888 * on the inactive queue, we may have to go all out.
889 */
890 int swap_pageouts_ok;
891 struct vnode *vp = NULL;
892
893 object = m->object;
894
895 if ((object->type != OBJT_SWAP) && (object->type != OBJT_DEFAULT)) {
896 swap_pageouts_ok = 1;
897 } else {
898 swap_pageouts_ok = !(defer_swap_pageouts || disable_swap_pageouts);
899 swap_pageouts_ok |= (!disable_swap_pageouts && defer_swap_pageouts &&
900 vm_page_count_min());
901
902 }
903
904 /*
905 * We don't bother paging objects that are "dead".
906 * Those objects are in a "rundown" state.
907 */
908 if (!swap_pageouts_ok || (object->flags & OBJ_DEAD)) {
984263bc
MD
909 TAILQ_REMOVE(&vm_page_queues[PQ_INACTIVE].pl, m, pageq);
910 TAILQ_INSERT_TAIL(&vm_page_queues[PQ_INACTIVE].pl, m, pageq);
984263bc
MD
911 continue;
912 }
913
914 /*
915 * The object is already known NOT to be dead. It
916 * is possible for the vget() to block the whole
917 * pageout daemon, but the new low-memory handling
918 * code should prevent it.
919 *
920 * The previous code skipped locked vnodes and, worse,
921 * reordered pages in the queue. This results in
922 * completely non-deterministic operation because,
923 * quite often, a vm_fault has initiated an I/O and
924 * is holding a locked vnode at just the point where
925 * the pageout daemon is woken up.
926 *
927 * We can't wait forever for the vnode lock, we might
928 * deadlock due to a vn_read() getting stuck in
929 * vm_wait while holding this vnode. We skip the
930 * vnode if we can't get it in a reasonable amount
931 * of time.
932 */
933
934 if (object->type == OBJT_VNODE) {
935 vp = object->handle;
936
87de5057 937 if (vget(vp, LK_EXCLUSIVE|LK_NOOBJ|LK_TIMELOCK)) {
984263bc
MD
938 ++pageout_lock_miss;
939 if (object->flags & OBJ_MIGHTBEDIRTY)
940 vnodes_skipped++;
941 continue;
942 }
943
944 /*
945 * The page might have been moved to another
946 * queue during potential blocking in vget()
947 * above. The page might have been freed and
948 * reused for another vnode. The object might
949 * have been reused for another vnode.
950 */
951 if (m->queue != PQ_INACTIVE ||
952 m->object != object ||
953 object->handle != vp) {
954 if (object->flags & OBJ_MIGHTBEDIRTY)
955 vnodes_skipped++;
956 vput(vp);
957 continue;
958 }
959
960 /*
961 * The page may have been busied during the
962 * blocking in vput(); We don't move the
963 * page back onto the end of the queue so that
964 * statistics are more correct if we don't.
965 */
966 if (m->busy || (m->flags & PG_BUSY)) {
967 vput(vp);
968 continue;
969 }
970
971 /*
972 * If the page has become held it might
973 * be undergoing I/O, so skip it
974 */
975 if (m->hold_count) {
984263bc
MD
976 TAILQ_REMOVE(&vm_page_queues[PQ_INACTIVE].pl, m, pageq);
977 TAILQ_INSERT_TAIL(&vm_page_queues[PQ_INACTIVE].pl, m, pageq);
984263bc
MD
978 if (object->flags & OBJ_MIGHTBEDIRTY)
979 vnodes_skipped++;
980 vput(vp);
981 continue;
982 }
983 }
984
985 /*
986 * If a page is dirty, then it is either being washed
987 * (but not yet cleaned) or it is still in the
988 * laundry. If it is still in the laundry, then we
989 * start the cleaning operation.
990 *
991 * This operation may cluster, invalidating the 'next'
992 * pointer. To prevent an inordinate number of
993 * restarts we use our marker to remember our place.
994 *
995 * decrement page_shortage on success to account for
996 * the (future) cleaned page. Otherwise we could wind
997 * up laundering or cleaning too many pages.
998 */
984263bc 999 TAILQ_INSERT_AFTER(&vm_page_queues[PQ_INACTIVE].pl, m, &marker, pageq);
984263bc
MD
1000 if (vm_pageout_clean(m) != 0) {
1001 --page_shortage;
1002 --maxlaunder;
1003 }
984263bc
MD
1004 next = TAILQ_NEXT(&marker, pageq);
1005 TAILQ_REMOVE(&vm_page_queues[PQ_INACTIVE].pl, &marker, pageq);
984263bc
MD
1006 if (vp != NULL)
1007 vput(vp);
1008 }
1009 }
1010
1011 /*
1012 * Compute the number of pages we want to try to move from the
1013 * active queue to the inactive queue.
1014 */
1015 page_shortage = vm_paging_target() +
12e4aaff 1016 vmstats.v_inactive_target - vmstats.v_inactive_count;
984263bc
MD
1017 page_shortage += addl_page_shortage;
1018
1019 /*
1020 * Scan the active queue for things we can deactivate. We nominally
1021 * track the per-page activity counter and use it to locate
1022 * deactivation candidates.
06ecca5a 1023 *
5fd012e0 1024 * NOTE: we are still in a critical section.
984263bc 1025 */
12e4aaff 1026 pcount = vmstats.v_active_count;
984263bc
MD
1027 m = TAILQ_FIRST(&vm_page_queues[PQ_ACTIVE].pl);
1028
1029 while ((m != NULL) && (pcount-- > 0) && (page_shortage > 0)) {
06ecca5a
MD
1030 /*
1031 * Give interrupts a chance.
1032 */
5fd012e0
MD
1033 crit_exit();
1034 crit_enter();
984263bc
MD
1035
1036 /*
06ecca5a 1037 * If the page was ripped out from under us, just stop.
984263bc 1038 */
06ecca5a 1039 if (m->queue != PQ_ACTIVE)
984263bc 1040 break;
984263bc 1041 next = TAILQ_NEXT(m, pageq);
06ecca5a 1042
984263bc
MD
1043 /*
1044 * Don't deactivate pages that are busy.
1045 */
1046 if ((m->busy != 0) ||
1047 (m->flags & PG_BUSY) ||
1048 (m->hold_count != 0)) {
984263bc
MD
1049 TAILQ_REMOVE(&vm_page_queues[PQ_ACTIVE].pl, m, pageq);
1050 TAILQ_INSERT_TAIL(&vm_page_queues[PQ_ACTIVE].pl, m, pageq);
984263bc
MD
1051 m = next;
1052 continue;
1053 }
1054
1055 /*
1056 * The count for pagedaemon pages is done after checking the
1057 * page for eligibility...
1058 */
12e4aaff 1059 mycpu->gd_cnt.v_pdpages++;
984263bc
MD
1060
1061 /*
1062 * Check to see "how much" the page has been used.
1063 */
1064 actcount = 0;
1065 if (m->object->ref_count != 0) {
1066 if (m->flags & PG_REFERENCED) {
1067 actcount += 1;
1068 }
1069 actcount += pmap_ts_referenced(m);
1070 if (actcount) {
1071 m->act_count += ACT_ADVANCE + actcount;
1072 if (m->act_count > ACT_MAX)
1073 m->act_count = ACT_MAX;
1074 }
1075 }
1076
1077 /*
1078 * Since we have "tested" this bit, we need to clear it now.
1079 */
1080 vm_page_flag_clear(m, PG_REFERENCED);
1081
1082 /*
1083 * Only if an object is currently being used, do we use the
1084 * page activation count stats.
1085 */
1086 if (actcount && (m->object->ref_count != 0)) {
984263bc
MD
1087 TAILQ_REMOVE(&vm_page_queues[PQ_ACTIVE].pl, m, pageq);
1088 TAILQ_INSERT_TAIL(&vm_page_queues[PQ_ACTIVE].pl, m, pageq);
984263bc
MD
1089 } else {
1090 m->act_count -= min(m->act_count, ACT_DECLINE);
1091 if (vm_pageout_algorithm ||
1092 m->object->ref_count == 0 ||
b5ccee96 1093 m->act_count < pass) {
984263bc
MD
1094 page_shortage--;
1095 if (m->object->ref_count == 0) {
1096 vm_page_protect(m, VM_PROT_NONE);
1097 if (m->dirty == 0)
1098 vm_page_cache(m);
1099 else
1100 vm_page_deactivate(m);
1101 } else {
1102 vm_page_deactivate(m);
1103 }
1104 } else {
984263bc
MD
1105 TAILQ_REMOVE(&vm_page_queues[PQ_ACTIVE].pl, m, pageq);
1106 TAILQ_INSERT_TAIL(&vm_page_queues[PQ_ACTIVE].pl, m, pageq);
984263bc
MD
1107 }
1108 }
1109 m = next;
1110 }
1111
984263bc
MD
1112 /*
1113 * We try to maintain some *really* free pages, this allows interrupt
1114 * code to be guaranteed space. Since both cache and free queues
1115 * are considered basically 'free', moving pages from cache to free
1116 * does not effect other calculations.
06ecca5a 1117 *
5fd012e0 1118 * NOTE: we are still in a critical section.
984263bc
MD
1119 */
1120
12e4aaff 1121 while (vmstats.v_free_count < vmstats.v_free_reserved) {
984263bc
MD
1122 static int cache_rover = 0;
1123 m = vm_page_list_find(PQ_CACHE, cache_rover, FALSE);
1124 if (!m)
1125 break;
1126 if ((m->flags & (PG_BUSY|PG_UNMANAGED)) ||
1127 m->busy ||
1128 m->hold_count ||
1129 m->wire_count) {
1130#ifdef INVARIANTS
086c1d7e 1131 kprintf("Warning: busy page %p found in cache\n", m);
984263bc
MD
1132#endif
1133 vm_page_deactivate(m);
1134 continue;
1135 }
1136 cache_rover = (cache_rover + PQ_PRIME2) & PQ_L2_MASK;
1137 vm_pageout_page_free(m);
12e4aaff 1138 mycpu->gd_cnt.v_dfree++;
984263bc 1139 }
06ecca5a 1140
5fd012e0 1141 crit_exit();
984263bc
MD
1142
1143#if !defined(NO_SWAPPING)
1144 /*
1145 * Idle process swapout -- run once per second.
1146 */
1147 if (vm_swap_idle_enabled) {
1148 static long lsec;
1149 if (time_second != lsec) {
1150 vm_pageout_req_swapout |= VM_SWAP_IDLE;
1151 vm_req_vmdaemon();
1152 lsec = time_second;
1153 }
1154 }
1155#endif
1156
1157 /*
1158 * If we didn't get enough free pages, and we have skipped a vnode
1159 * in a writeable object, wakeup the sync daemon. And kick swapout
1160 * if we did not get enough free pages.
1161 */
1162 if (vm_paging_target() > 0) {
1163 if (vnodes_skipped && vm_page_count_min())
418ff780 1164 speedup_syncer();
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MD
1165#if !defined(NO_SWAPPING)
1166 if (vm_swap_enabled && vm_page_count_target()) {
1167 vm_req_vmdaemon();
1168 vm_pageout_req_swapout |= VM_SWAP_NORMAL;
1169 }
1170#endif
1171 }
1172
1173 /*
1174 * If we are out of swap and were not able to reach our paging
1175 * target, kill the largest process.
1176 */
1177 if ((vm_swap_size < 64 && vm_page_count_min()) ||
1178 (swap_pager_full && vm_paging_target() > 0)) {
1179#if 0
1180 if ((vm_swap_size < 64 || swap_pager_full) && vm_page_count_min()) {
1181#endif
8fa76237
MD
1182 info.bigproc = NULL;
1183 info.bigsize = 0;
1184 allproc_scan(vm_pageout_scan_callback, &info);
1185 if (info.bigproc != NULL) {
1186 killproc(info.bigproc, "out of swap space");
1187 info.bigproc->p_nice = PRIO_MIN;
08f2f1bb
SS
1188 info.bigproc->p_usched->resetpriority(
1189 FIRST_LWP_IN_PROC(info.bigproc));
12e4aaff 1190 wakeup(&vmstats.v_free_count);
8fa76237 1191 PRELE(info.bigproc);
984263bc
MD
1192 }
1193 }
1194}
1195
8fa76237
MD
1196static int
1197vm_pageout_scan_callback(struct proc *p, void *data)
1198{
1199 struct vm_pageout_scan_info *info = data;
1200 vm_offset_t size;
1201
1202 /*
1203 * if this is a system process, skip it
1204 */
1205 if ((p->p_flag & P_SYSTEM) || (p->p_pid == 1) ||
1206 ((p->p_pid < 48) && (vm_swap_size != 0))) {
1207 return (0);
1208 }
1209
1210 /*
1211 * if the process is in a non-running type state,
1212 * don't touch it.
1213 */
164b8401 1214 if (p->p_stat != SACTIVE && p->p_stat != SSTOP) {
8fa76237
MD
1215 return (0);
1216 }
1217
1218 /*
1219 * get the process size
1220 */
1221 size = vmspace_resident_count(p->p_vmspace) +
1222 vmspace_swap_count(p->p_vmspace);
1223
1224 /*
1225 * If the this process is bigger than the biggest one
1226 * remember it.
1227 */
1228 if (size > info->bigsize) {
1229 if (info->bigproc)
1230 PRELE(info->bigproc);
1231 PHOLD(p);
1232 info->bigproc = p;
1233 info->bigsize = size;
1234 }
1235 return(0);
1236}
1237
984263bc
MD
1238/*
1239 * This routine tries to maintain the pseudo LRU active queue,
1240 * so that during long periods of time where there is no paging,
1241 * that some statistic accumulation still occurs. This code
1242 * helps the situation where paging just starts to occur.
1243 */
1244static void
57e43348 1245vm_pageout_page_stats(void)
984263bc 1246{
984263bc
MD
1247 vm_page_t m,next;
1248 int pcount,tpcount; /* Number of pages to check */
1249 static int fullintervalcount = 0;
1250 int page_shortage;
984263bc
MD
1251
1252 page_shortage =
12e4aaff
MD
1253 (vmstats.v_inactive_target + vmstats.v_cache_max + vmstats.v_free_min) -
1254 (vmstats.v_free_count + vmstats.v_inactive_count + vmstats.v_cache_count);
984263bc
MD
1255
1256 if (page_shortage <= 0)
1257 return;
1258
5fd012e0 1259 crit_enter();
984263bc 1260
12e4aaff 1261 pcount = vmstats.v_active_count;
984263bc
MD
1262 fullintervalcount += vm_pageout_stats_interval;
1263 if (fullintervalcount < vm_pageout_full_stats_interval) {
12e4aaff 1264 tpcount = (vm_pageout_stats_max * vmstats.v_active_count) / vmstats.v_page_count;
984263bc
MD
1265 if (pcount > tpcount)
1266 pcount = tpcount;
1267 } else {
1268 fullintervalcount = 0;
1269 }
1270
1271 m = TAILQ_FIRST(&vm_page_queues[PQ_ACTIVE].pl);
1272 while ((m != NULL) && (pcount-- > 0)) {
1273 int actcount;
1274
1275 if (m->queue != PQ_ACTIVE) {
1276 break;
1277 }
1278
1279 next = TAILQ_NEXT(m, pageq);
1280 /*
1281 * Don't deactivate pages that are busy.
1282 */
1283 if ((m->busy != 0) ||
1284 (m->flags & PG_BUSY) ||
1285 (m->hold_count != 0)) {
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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 m = next;
1289 continue;
1290 }
1291
1292 actcount = 0;
1293 if (m->flags & PG_REFERENCED) {
1294 vm_page_flag_clear(m, PG_REFERENCED);
1295 actcount += 1;
1296 }
1297
1298 actcount += pmap_ts_referenced(m);
1299 if (actcount) {
1300 m->act_count += ACT_ADVANCE + actcount;
1301 if (m->act_count > ACT_MAX)
1302 m->act_count = ACT_MAX;
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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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MD
1305 } else {
1306 if (m->act_count == 0) {
1307 /*
1308 * We turn off page access, so that we have
1309 * more accurate RSS stats. We don't do this
1310 * in the normal page deactivation when the
1311 * system is loaded VM wise, because the
1312 * cost of the large number of page protect
1313 * operations would be higher than the value
1314 * of doing the operation.
1315 */
1316 vm_page_protect(m, VM_PROT_NONE);
1317 vm_page_deactivate(m);
1318 } else {
1319 m->act_count -= min(m->act_count, ACT_DECLINE);
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1320 TAILQ_REMOVE(&vm_page_queues[PQ_ACTIVE].pl, m, pageq);
1321 TAILQ_INSERT_TAIL(&vm_page_queues[PQ_ACTIVE].pl, m, pageq);
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1322 }
1323 }
1324
1325 m = next;
1326 }
5fd012e0 1327 crit_exit();
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1328}
1329
1330static int
57e43348 1331vm_pageout_free_page_calc(vm_size_t count)
984263bc 1332{
12e4aaff 1333 if (count < vmstats.v_page_count)
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1334 return 0;
1335 /*
1336 * free_reserved needs to include enough for the largest swap pager
1337 * structures plus enough for any pv_entry structs when paging.
1338 */
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MD
1339 if (vmstats.v_page_count > 1024)
1340 vmstats.v_free_min = 4 + (vmstats.v_page_count - 1024) / 200;
984263bc 1341 else
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1342 vmstats.v_free_min = 4;
1343 vmstats.v_pageout_free_min = (2*MAXBSIZE)/PAGE_SIZE +
1344 vmstats.v_interrupt_free_min;
1345 vmstats.v_free_reserved = vm_pageout_page_count +
1346 vmstats.v_pageout_free_min + (count / 768) + PQ_L2_SIZE;
1347 vmstats.v_free_severe = vmstats.v_free_min / 2;
1348 vmstats.v_free_min += vmstats.v_free_reserved;
1349 vmstats.v_free_severe += vmstats.v_free_reserved;
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1350 return 1;
1351}
1352
1353
1354/*
1355 * vm_pageout is the high level pageout daemon.
1356 */
1357static void
57e43348 1358vm_pageout(void)
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1359{
1360 int pass;
1361
1362 /*
1363 * Initialize some paging parameters.
1364 */
1365
12e4aaff
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1366 vmstats.v_interrupt_free_min = 2;
1367 if (vmstats.v_page_count < 2000)
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1368 vm_pageout_page_count = 8;
1369
12e4aaff 1370 vm_pageout_free_page_calc(vmstats.v_page_count);
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1371 /*
1372 * v_free_target and v_cache_min control pageout hysteresis. Note
1373 * that these are more a measure of the VM cache queue hysteresis
1374 * then the VM free queue. Specifically, v_free_target is the
1375 * high water mark (free+cache pages).
1376 *
1377 * v_free_reserved + v_cache_min (mostly means v_cache_min) is the
1378 * low water mark, while v_free_min is the stop. v_cache_min must
1379 * be big enough to handle memory needs while the pageout daemon
1380 * is signalled and run to free more pages.
1381 */
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1382 if (vmstats.v_free_count > 6144)
1383 vmstats.v_free_target = 4 * vmstats.v_free_min + vmstats.v_free_reserved;
984263bc 1384 else
12e4aaff 1385 vmstats.v_free_target = 2 * vmstats.v_free_min + vmstats.v_free_reserved;
984263bc 1386
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1387 if (vmstats.v_free_count > 2048) {
1388 vmstats.v_cache_min = vmstats.v_free_target;
1389 vmstats.v_cache_max = 2 * vmstats.v_cache_min;
1390 vmstats.v_inactive_target = (3 * vmstats.v_free_target) / 2;
984263bc 1391 } else {
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1392 vmstats.v_cache_min = 0;
1393 vmstats.v_cache_max = 0;
1394 vmstats.v_inactive_target = vmstats.v_free_count / 4;
984263bc 1395 }
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1396 if (vmstats.v_inactive_target > vmstats.v_free_count / 3)
1397 vmstats.v_inactive_target = vmstats.v_free_count / 3;
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1398
1399 /* XXX does not really belong here */
1400 if (vm_page_max_wired == 0)
12e4aaff 1401 vm_page_max_wired = vmstats.v_free_count / 3;
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1402
1403 if (vm_pageout_stats_max == 0)
12e4aaff 1404 vm_pageout_stats_max = vmstats.v_free_target;
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1405
1406 /*
1407 * Set interval in seconds for stats scan.
1408 */
1409 if (vm_pageout_stats_interval == 0)
1410 vm_pageout_stats_interval = 5;
1411 if (vm_pageout_full_stats_interval == 0)
1412 vm_pageout_full_stats_interval = vm_pageout_stats_interval * 4;
1413
1414
1415 /*
1416 * Set maximum free per pass
1417 */
1418 if (vm_pageout_stats_free_max == 0)
1419 vm_pageout_stats_free_max = 5;
1420
1421 swap_pager_swap_init();
1422 pass = 0;
1423 /*
1424 * The pageout daemon is never done, so loop forever.
1425 */
1426 while (TRUE) {
1427 int error;
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1428
1429 /*
1430 * If we have enough free memory, wakeup waiters. Do
1431 * not clear vm_pages_needed until we reach our target,
1432 * otherwise we may be woken up over and over again and
1433 * waste a lot of cpu.
1434 */
5fd012e0 1435 crit_enter();
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1436 if (vm_pages_needed && !vm_page_count_min()) {
1437 if (vm_paging_needed() <= 0)
1438 vm_pages_needed = 0;
12e4aaff 1439 wakeup(&vmstats.v_free_count);
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1440 }
1441 if (vm_pages_needed) {
1442 /*
1443 * Still not done, take a second pass without waiting
1444 * (unlimited dirty cleaning), otherwise sleep a bit
1445 * and try again.
1446 */
1447 ++pass;
1448 if (pass > 1)
377d4740 1449 tsleep(&vm_pages_needed, 0, "psleep", hz/2);
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1450 } else {
1451 /*
1452 * Good enough, sleep & handle stats. Prime the pass
1453 * for the next run.
1454 */
1455 if (pass > 1)
1456 pass = 1;
1457 else
1458 pass = 0;
1459 error = tsleep(&vm_pages_needed,
377d4740 1460 0, "psleep", vm_pageout_stats_interval * hz);
984263bc 1461 if (error && !vm_pages_needed) {
5fd012e0 1462 crit_exit();
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1463 pass = 0;
1464 vm_pageout_page_stats();
1465 continue;
1466 }
1467 }
1468
1469 if (vm_pages_needed)
12e4aaff 1470 mycpu->gd_cnt.v_pdwakeups++;
5fd012e0 1471 crit_exit();
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1472 vm_pageout_scan(pass);
1473 vm_pageout_deficit = 0;
1474 }
1475}
1476
1477void
57e43348 1478pagedaemon_wakeup(void)
984263bc 1479{
bc6dffab 1480 if (!vm_pages_needed && curthread != pagethread) {
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1481 vm_pages_needed++;
1482 wakeup(&vm_pages_needed);
1483 }
1484}
1485
1486#if !defined(NO_SWAPPING)
1487static void
57e43348 1488vm_req_vmdaemon(void)
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1489{
1490 static int lastrun = 0;
1491
1492 if ((ticks > (lastrun + hz)) || (ticks < lastrun)) {
1493 wakeup(&vm_daemon_needed);
1494 lastrun = ticks;
1495 }
1496}
1497
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1498static int vm_daemon_callback(struct proc *p, void *data __unused);
1499
984263bc 1500static void
57e43348 1501vm_daemon(void)
984263bc 1502{
984263bc 1503 while (TRUE) {
377d4740 1504 tsleep(&vm_daemon_needed, 0, "psleep", 0);
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1505 if (vm_pageout_req_swapout) {
1506 swapout_procs(vm_pageout_req_swapout);
1507 vm_pageout_req_swapout = 0;
1508 }
1509 /*
1510 * scan the processes for exceeding their rlimits or if
1511 * process is swapped out -- deactivate pages
1512 */
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1513 allproc_scan(vm_daemon_callback, NULL);
1514 }
1515}
984263bc 1516
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1517static int
1518vm_daemon_callback(struct proc *p, void *data __unused)
1519{
1520 vm_pindex_t limit, size;
984263bc 1521
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1522 /*
1523 * if this is a system process or if we have already
1524 * looked at this process, skip it.
1525 */
1526 if (p->p_flag & (P_SYSTEM | P_WEXIT))
1527 return (0);
984263bc 1528
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1529 /*
1530 * if the process is in a non-running type state,
1531 * don't touch it.
1532 */
164b8401 1533 if (p->p_stat != SACTIVE && p->p_stat != SSTOP)
8fa76237 1534 return (0);
984263bc 1535
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1536 /*
1537 * get a limit
1538 */
1539 limit = OFF_TO_IDX(qmin(p->p_rlimit[RLIMIT_RSS].rlim_cur,
1540 p->p_rlimit[RLIMIT_RSS].rlim_max));
1541
1542 /*
1543 * let processes that are swapped out really be
1544 * swapped out. Set the limit to nothing to get as
1545 * many pages out to swap as possible.
1546 */
1547 if (p->p_flag & P_SWAPPEDOUT)
1548 limit = 0;
1549
1550 size = vmspace_resident_count(p->p_vmspace);
1551 if (limit >= 0 && size >= limit) {
1552 vm_pageout_map_deactivate_pages(
1553 &p->p_vmspace->vm_map, limit);
984263bc 1554 }
8fa76237 1555 return (0);
984263bc 1556}
8fa76237 1557
984263bc 1558#endif