vnode_pager_haspage() could return TRUE but leave *before and *after
[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 $
4ecf7cc9 69 * $DragonFly: src/sys/vm/vm_pageout.c,v 1.36 2008/07/01 02:02:56 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 /*
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395 * Initiate I/O. Bump the vm_page_t->busy counter.
396 */
397 for (i = 0; i < count; i++) {
398 KASSERT(mc[i]->valid == VM_PAGE_BITS_ALL, ("vm_pageout_flush page %p index %d/%d: partially invalid page", mc[i], i, count));
399 vm_page_io_start(mc[i]);
400 }
401
402 /*
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MD
403 * We must make the pages read-only. This will also force the
404 * modified bit in the related pmaps to be cleared. The pager
405 * cannot clear the bit for us since the I/O completion code
406 * typically runs from an interrupt. The act of making the page
407 * read-only handles the case for us.
984263bc 408 */
984263bc 409 for (i = 0; i < count; i++) {
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410 vm_page_protect(mc[i], VM_PROT_READ);
411 }
412
413 object = mc[0]->object;
414 vm_object_pip_add(object, count);
415
416 vm_pager_put_pages(object, mc, count,
c439ad8f 417 (flags | ((object == &kernel_object) ? VM_PAGER_PUT_SYNC : 0)),
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418 pageout_status);
419
420 for (i = 0; i < count; i++) {
421 vm_page_t mt = mc[i];
422
423 switch (pageout_status[i]) {
424 case VM_PAGER_OK:
425 numpagedout++;
426 break;
427 case VM_PAGER_PEND:
428 numpagedout++;
429 break;
430 case VM_PAGER_BAD:
431 /*
432 * Page outside of range of object. Right now we
433 * essentially lose the changes by pretending it
434 * worked.
435 */
436 pmap_clear_modify(mt);
437 vm_page_undirty(mt);
438 break;
439 case VM_PAGER_ERROR:
440 case VM_PAGER_FAIL:
441 /*
c84c24da
MD
442 * A page typically cannot be paged out when we
443 * have run out of swap. We leave the page
444 * marked inactive and will try to page it out
445 * again later.
446 *
447 * Starvation of the active page list is used to
448 * determine when the system is massively memory
449 * starved.
984263bc 450 */
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MD
451 break;
452 case VM_PAGER_AGAIN:
453 break;
454 }
455
456 /*
457 * If the operation is still going, leave the page busy to
458 * block all other accesses. Also, leave the paging in
459 * progress indicator set so that we don't attempt an object
460 * collapse.
93afe6be
MD
461 *
462 * For any pages which have completed synchronously,
463 * deactivate the page if we are under a severe deficit.
464 * Do not try to enter them into the cache, though, they
465 * might still be read-heavy.
984263bc
MD
466 */
467 if (pageout_status[i] != VM_PAGER_PEND) {
468 vm_object_pip_wakeup(object);
469 vm_page_io_finish(mt);
93afe6be
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470 if (vm_page_count_severe())
471 vm_page_deactivate(mt);
472#if 0
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473 if (!vm_page_count_severe() || !vm_page_try_to_cache(mt))
474 vm_page_protect(mt, VM_PROT_READ);
93afe6be 475#endif
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MD
476 }
477 }
478 return numpagedout;
479}
480
481#if !defined(NO_SWAPPING)
482/*
483 * vm_pageout_object_deactivate_pages
484 *
485 * deactivate enough pages to satisfy the inactive target
486 * requirements or if vm_page_proc_limit is set, then
487 * deactivate all of the pages in the object and its
488 * backing_objects.
489 *
490 * The object and map must be locked.
491 */
1f804340
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492static int vm_pageout_object_deactivate_pages_callback(vm_page_t, void *);
493
984263bc 494static void
57e43348 495vm_pageout_object_deactivate_pages(vm_map_t map, vm_object_t object,
06ecca5a 496 vm_pindex_t desired, int map_remove_only)
984263bc 497{
1f804340 498 struct rb_vm_page_scan_info info;
984263bc 499 int remove_mode;
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MD
500
501 if (object->type == OBJT_DEVICE || object->type == OBJT_PHYS)
502 return;
503
504 while (object) {
505 if (pmap_resident_count(vm_map_pmap(map)) <= desired)
506 return;
507 if (object->paging_in_progress)
508 return;
509
510 remove_mode = map_remove_only;
511 if (object->shadow_count > 1)
512 remove_mode = 1;
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513
514 /*
515 * scan the objects entire memory queue. spl protection is
516 * required to avoid an interrupt unbusy/free race against
517 * our busy check.
518 */
5fd012e0 519 crit_enter();
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520 info.limit = remove_mode;
521 info.map = map;
522 info.desired = desired;
523 vm_page_rb_tree_RB_SCAN(&object->rb_memq, NULL,
524 vm_pageout_object_deactivate_pages_callback,
525 &info
526 );
527 crit_exit();
528 object = object->backing_object;
529 }
530}
531
532static int
533vm_pageout_object_deactivate_pages_callback(vm_page_t p, void *data)
534{
535 struct rb_vm_page_scan_info *info = data;
536 int actcount;
984263bc 537
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538 if (pmap_resident_count(vm_map_pmap(info->map)) <= info->desired) {
539 return(-1);
540 }
541 mycpu->gd_cnt.v_pdpages++;
542 if (p->wire_count != 0 || p->hold_count != 0 || p->busy != 0 ||
543 (p->flags & (PG_BUSY|PG_UNMANAGED)) ||
544 !pmap_page_exists_quick(vm_map_pmap(info->map), p)) {
545 return(0);
546 }
984263bc 547
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548 actcount = pmap_ts_referenced(p);
549 if (actcount) {
550 vm_page_flag_set(p, PG_REFERENCED);
551 } else if (p->flags & PG_REFERENCED) {
552 actcount = 1;
553 }
554
555 if ((p->queue != PQ_ACTIVE) &&
556 (p->flags & PG_REFERENCED)) {
557 vm_page_activate(p);
558 p->act_count += actcount;
559 vm_page_flag_clear(p, PG_REFERENCED);
560 } else if (p->queue == PQ_ACTIVE) {
561 if ((p->flags & PG_REFERENCED) == 0) {
562 p->act_count -= min(p->act_count, ACT_DECLINE);
563 if (!info->limit && (vm_pageout_algorithm || (p->act_count == 0))) {
17cde63e 564 vm_page_busy(p);
984263bc 565 vm_page_protect(p, VM_PROT_NONE);
17cde63e 566 vm_page_wakeup(p);
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567 vm_page_deactivate(p);
568 } else {
569 TAILQ_REMOVE(&vm_page_queues[PQ_ACTIVE].pl, p, pageq);
570 TAILQ_INSERT_TAIL(&vm_page_queues[PQ_ACTIVE].pl, p, pageq);
984263bc 571 }
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572 } else {
573 vm_page_activate(p);
574 vm_page_flag_clear(p, PG_REFERENCED);
575 if (p->act_count < (ACT_MAX - ACT_ADVANCE))
576 p->act_count += ACT_ADVANCE;
577 TAILQ_REMOVE(&vm_page_queues[PQ_ACTIVE].pl, p, pageq);
578 TAILQ_INSERT_TAIL(&vm_page_queues[PQ_ACTIVE].pl, p, pageq);
984263bc 579 }
1f804340 580 } else if (p->queue == PQ_INACTIVE) {
17cde63e 581 vm_page_busy(p);
1f804340 582 vm_page_protect(p, VM_PROT_NONE);
17cde63e 583 vm_page_wakeup(p);
984263bc 584 }
1f804340 585 return(0);
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MD
586}
587
588/*
589 * deactivate some number of pages in a map, try to do it fairly, but
590 * that is really hard to do.
591 */
592static void
57e43348 593vm_pageout_map_deactivate_pages(vm_map_t map, vm_pindex_t desired)
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594{
595 vm_map_entry_t tmpe;
596 vm_object_t obj, bigobj;
597 int nothingwired;
598
df4f70a6 599 if (lockmgr(&map->lock, LK_EXCLUSIVE | LK_NOWAIT)) {
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MD
600 return;
601 }
602
603 bigobj = NULL;
604 nothingwired = TRUE;
605
606 /*
607 * first, search out the biggest object, and try to free pages from
608 * that.
609 */
610 tmpe = map->header.next;
611 while (tmpe != &map->header) {
1b874851
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612 switch(tmpe->maptype) {
613 case VM_MAPTYPE_NORMAL:
614 case VM_MAPTYPE_VPAGETABLE:
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615 obj = tmpe->object.vm_object;
616 if ((obj != NULL) && (obj->shadow_count <= 1) &&
617 ((bigobj == NULL) ||
618 (bigobj->resident_page_count < obj->resident_page_count))) {
619 bigobj = obj;
620 }
1b874851
MD
621 break;
622 default:
623 break;
984263bc
MD
624 }
625 if (tmpe->wired_count > 0)
626 nothingwired = FALSE;
627 tmpe = tmpe->next;
628 }
629
630 if (bigobj)
631 vm_pageout_object_deactivate_pages(map, bigobj, desired, 0);
632
633 /*
634 * Next, hunt around for other pages to deactivate. We actually
635 * do this search sort of wrong -- .text first is not the best idea.
636 */
637 tmpe = map->header.next;
638 while (tmpe != &map->header) {
639 if (pmap_resident_count(vm_map_pmap(map)) <= desired)
640 break;
1b874851
MD
641 switch(tmpe->maptype) {
642 case VM_MAPTYPE_NORMAL:
643 case VM_MAPTYPE_VPAGETABLE:
984263bc
MD
644 obj = tmpe->object.vm_object;
645 if (obj)
646 vm_pageout_object_deactivate_pages(map, obj, desired, 0);
1b874851
MD
647 break;
648 default:
649 break;
984263bc
MD
650 }
651 tmpe = tmpe->next;
652 };
653
654 /*
655 * Remove all mappings if a process is swapped out, this will free page
656 * table pages.
657 */
658 if (desired == 0 && nothingwired)
659 pmap_remove(vm_map_pmap(map),
88181b08 660 VM_MIN_USER_ADDRESS, VM_MAX_USER_ADDRESS);
984263bc 661 vm_map_unlock(map);
984263bc
MD
662}
663#endif
664
665/*
a11aaa81
MD
666 * Don't try to be fancy - being fancy can lead to vnode deadlocks. We
667 * only do it for OBJT_DEFAULT and OBJT_SWAP objects which we know can
668 * be trivially freed.
984263bc 669 */
984263bc 670void
95813af0
MD
671vm_pageout_page_free(vm_page_t m)
672{
984263bc
MD
673 vm_object_t object = m->object;
674 int type = object->type;
675
676 if (type == OBJT_SWAP || type == OBJT_DEFAULT)
677 vm_object_reference(object);
678 vm_page_busy(m);
679 vm_page_protect(m, VM_PROT_NONE);
680 vm_page_free(m);
681 if (type == OBJT_SWAP || type == OBJT_DEFAULT)
682 vm_object_deallocate(object);
683}
684
685/*
686 * vm_pageout_scan does the dirty work for the pageout daemon.
687 */
8fa76237
MD
688
689struct vm_pageout_scan_info {
690 struct proc *bigproc;
691 vm_offset_t bigsize;
692};
693
694static int vm_pageout_scan_callback(struct proc *p, void *data);
695
984263bc
MD
696static void
697vm_pageout_scan(int pass)
698{
8fa76237 699 struct vm_pageout_scan_info info;
984263bc
MD
700 vm_page_t m, next;
701 struct vm_page marker;
702 int page_shortage, maxscan, pcount;
703 int addl_page_shortage, addl_page_shortage_init;
984263bc
MD
704 vm_object_t object;
705 int actcount;
706 int vnodes_skipped = 0;
c84c24da 707 int pages_freed = 0;
984263bc 708 int maxlaunder;
984263bc
MD
709
710 /*
711 * Do whatever cleanup that the pmap code can.
712 */
713 pmap_collect();
714
715 addl_page_shortage_init = vm_pageout_deficit;
716 vm_pageout_deficit = 0;
717
718 /*
719 * Calculate the number of pages we want to either free or move
720 * to the cache.
721 */
722 page_shortage = vm_paging_target() + addl_page_shortage_init;
723
724 /*
725 * Initialize our marker
726 */
727 bzero(&marker, sizeof(marker));
728 marker.flags = PG_BUSY | PG_FICTITIOUS | PG_MARKER;
729 marker.queue = PQ_INACTIVE;
730 marker.wire_count = 1;
731
732 /*
733 * Start scanning the inactive queue for pages we can move to the
734 * cache or free. The scan will stop when the target is reached or
735 * we have scanned the entire inactive queue. Note that m->act_count
736 * is not used to form decisions for the inactive queue, only for the
737 * active queue.
738 *
739 * maxlaunder limits the number of dirty pages we flush per scan.
740 * For most systems a smaller value (16 or 32) is more robust under
741 * extreme memory and disk pressure because any unnecessary writes
742 * to disk can result in extreme performance degredation. However,
743 * systems with excessive dirty pages (especially when MAP_NOSYNC is
744 * used) will die horribly with limited laundering. If the pageout
745 * daemon cannot clean enough pages in the first pass, we let it go
746 * all out in succeeding passes.
747 */
748 if ((maxlaunder = vm_max_launder) <= 1)
749 maxlaunder = 1;
750 if (pass)
751 maxlaunder = 10000;
752
06ecca5a 753 /*
5fd012e0
MD
754 * We will generally be in a critical section throughout the
755 * scan, but we can release it temporarily when we are sitting on a
756 * non-busy page without fear. this is required to prevent an
757 * interrupt from unbusying or freeing a page prior to our busy
758 * check, leaving us on the wrong queue or checking the wrong
759 * page.
06ecca5a 760 */
5fd012e0 761 crit_enter();
984263bc
MD
762rescan0:
763 addl_page_shortage = addl_page_shortage_init;
12e4aaff 764 maxscan = vmstats.v_inactive_count;
984263bc
MD
765 for (m = TAILQ_FIRST(&vm_page_queues[PQ_INACTIVE].pl);
766 m != NULL && maxscan-- > 0 && page_shortage > 0;
06ecca5a
MD
767 m = next
768 ) {
12e4aaff 769 mycpu->gd_cnt.v_pdpages++;
984263bc 770
06ecca5a
MD
771 /*
772 * Give interrupts a chance
773 */
5fd012e0
MD
774 crit_exit();
775 crit_enter();
984263bc 776
06ecca5a
MD
777 /*
778 * It's easier for some of the conditions below to just loop
779 * and catch queue changes here rather then check everywhere
780 * else.
781 */
782 if (m->queue != PQ_INACTIVE)
783 goto rescan0;
984263bc
MD
784 next = TAILQ_NEXT(m, pageq);
785
786 /*
787 * skip marker pages
788 */
789 if (m->flags & PG_MARKER)
790 continue;
791
792 /*
793 * A held page may be undergoing I/O, so skip it.
794 */
795 if (m->hold_count) {
984263bc
MD
796 TAILQ_REMOVE(&vm_page_queues[PQ_INACTIVE].pl, m, pageq);
797 TAILQ_INSERT_TAIL(&vm_page_queues[PQ_INACTIVE].pl, m, pageq);
984263bc
MD
798 addl_page_shortage++;
799 continue;
800 }
06ecca5a 801
984263bc
MD
802 /*
803 * Dont mess with busy pages, keep in the front of the
804 * queue, most likely are being paged out.
805 */
806 if (m->busy || (m->flags & PG_BUSY)) {
807 addl_page_shortage++;
808 continue;
809 }
810
984263bc 811 if (m->object->ref_count == 0) {
06ecca5a
MD
812 /*
813 * If the object is not being used, we ignore previous
814 * references.
815 */
984263bc
MD
816 vm_page_flag_clear(m, PG_REFERENCED);
817 pmap_clear_reference(m);
818
984263bc 819 } else if (((m->flags & PG_REFERENCED) == 0) &&
06ecca5a
MD
820 (actcount = pmap_ts_referenced(m))) {
821 /*
822 * Otherwise, if the page has been referenced while
823 * in the inactive queue, we bump the "activation
824 * count" upwards, making it less likely that the
825 * page will be added back to the inactive queue
826 * prematurely again. Here we check the page tables
827 * (or emulated bits, if any), given the upper level
828 * VM system not knowing anything about existing
829 * references.
830 */
984263bc
MD
831 vm_page_activate(m);
832 m->act_count += (actcount + ACT_ADVANCE);
833 continue;
834 }
835
836 /*
837 * If the upper level VM system knows about any page
838 * references, we activate the page. We also set the
839 * "activation count" higher than normal so that we will less
840 * likely place pages back onto the inactive queue again.
841 */
842 if ((m->flags & PG_REFERENCED) != 0) {
843 vm_page_flag_clear(m, PG_REFERENCED);
844 actcount = pmap_ts_referenced(m);
845 vm_page_activate(m);
846 m->act_count += (actcount + ACT_ADVANCE + 1);
847 continue;
848 }
849
850 /*
851 * If the upper level VM system doesn't know anything about
852 * the page being dirty, we have to check for it again. As
853 * far as the VM code knows, any partially dirty pages are
854 * fully dirty.
41a01a4d
MD
855 *
856 * Pages marked PG_WRITEABLE may be mapped into the user
857 * address space of a process running on another cpu. A
858 * user process (without holding the MP lock) running on
859 * another cpu may be able to touch the page while we are
17cde63e
MD
860 * trying to remove it. vm_page_cache() will handle this
861 * case for us.
984263bc
MD
862 */
863 if (m->dirty == 0) {
864 vm_page_test_dirty(m);
865 } else {
866 vm_page_dirty(m);
867 }
868
984263bc 869 if (m->valid == 0) {
41a01a4d
MD
870 /*
871 * Invalid pages can be easily freed
872 */
984263bc 873 vm_pageout_page_free(m);
12e4aaff 874 mycpu->gd_cnt.v_dfree++;
984263bc 875 --page_shortage;
c84c24da 876 ++pages_freed;
984263bc
MD
877 } else if (m->dirty == 0) {
878 /*
41a01a4d
MD
879 * Clean pages can be placed onto the cache queue.
880 * This effectively frees them.
984263bc
MD
881 */
882 vm_page_cache(m);
883 --page_shortage;
c84c24da 884 ++pages_freed;
984263bc
MD
885 } else if ((m->flags & PG_WINATCFLS) == 0 && pass == 0) {
886 /*
887 * Dirty pages need to be paged out, but flushing
888 * a page is extremely expensive verses freeing
889 * a clean page. Rather then artificially limiting
890 * the number of pages we can flush, we instead give
891 * dirty pages extra priority on the inactive queue
892 * by forcing them to be cycled through the queue
893 * twice before being flushed, after which the
894 * (now clean) page will cycle through once more
895 * before being freed. This significantly extends
896 * the thrash point for a heavily loaded machine.
897 */
984263bc
MD
898 vm_page_flag_set(m, PG_WINATCFLS);
899 TAILQ_REMOVE(&vm_page_queues[PQ_INACTIVE].pl, m, pageq);
900 TAILQ_INSERT_TAIL(&vm_page_queues[PQ_INACTIVE].pl, m, pageq);
984263bc
MD
901 } else if (maxlaunder > 0) {
902 /*
903 * We always want to try to flush some dirty pages if
904 * we encounter them, to keep the system stable.
905 * Normally this number is small, but under extreme
906 * pressure where there are insufficient clean pages
907 * on the inactive queue, we may have to go all out.
908 */
909 int swap_pageouts_ok;
910 struct vnode *vp = NULL;
911
912 object = m->object;
913
914 if ((object->type != OBJT_SWAP) && (object->type != OBJT_DEFAULT)) {
915 swap_pageouts_ok = 1;
916 } else {
917 swap_pageouts_ok = !(defer_swap_pageouts || disable_swap_pageouts);
918 swap_pageouts_ok |= (!disable_swap_pageouts && defer_swap_pageouts &&
919 vm_page_count_min());
920
921 }
922
923 /*
924 * We don't bother paging objects that are "dead".
925 * Those objects are in a "rundown" state.
926 */
927 if (!swap_pageouts_ok || (object->flags & OBJ_DEAD)) {
984263bc
MD
928 TAILQ_REMOVE(&vm_page_queues[PQ_INACTIVE].pl, m, pageq);
929 TAILQ_INSERT_TAIL(&vm_page_queues[PQ_INACTIVE].pl, m, pageq);
984263bc
MD
930 continue;
931 }
932
933 /*
934 * The object is already known NOT to be dead. It
935 * is possible for the vget() to block the whole
936 * pageout daemon, but the new low-memory handling
937 * code should prevent it.
938 *
939 * The previous code skipped locked vnodes and, worse,
940 * reordered pages in the queue. This results in
941 * completely non-deterministic operation because,
942 * quite often, a vm_fault has initiated an I/O and
943 * is holding a locked vnode at just the point where
944 * the pageout daemon is woken up.
945 *
946 * We can't wait forever for the vnode lock, we might
947 * deadlock due to a vn_read() getting stuck in
948 * vm_wait while holding this vnode. We skip the
949 * vnode if we can't get it in a reasonable amount
950 * of time.
951 */
952
953 if (object->type == OBJT_VNODE) {
954 vp = object->handle;
955
87de5057 956 if (vget(vp, LK_EXCLUSIVE|LK_NOOBJ|LK_TIMELOCK)) {
984263bc
MD
957 ++pageout_lock_miss;
958 if (object->flags & OBJ_MIGHTBEDIRTY)
959 vnodes_skipped++;
960 continue;
961 }
962
963 /*
964 * The page might have been moved to another
965 * queue during potential blocking in vget()
966 * above. The page might have been freed and
967 * reused for another vnode. The object might
968 * have been reused for another vnode.
969 */
970 if (m->queue != PQ_INACTIVE ||
971 m->object != object ||
972 object->handle != vp) {
973 if (object->flags & OBJ_MIGHTBEDIRTY)
974 vnodes_skipped++;
975 vput(vp);
976 continue;
977 }
978
979 /*
980 * The page may have been busied during the
981 * blocking in vput(); We don't move the
982 * page back onto the end of the queue so that
983 * statistics are more correct if we don't.
984 */
985 if (m->busy || (m->flags & PG_BUSY)) {
986 vput(vp);
987 continue;
988 }
989
990 /*
991 * If the page has become held it might
992 * be undergoing I/O, so skip it
993 */
994 if (m->hold_count) {
984263bc
MD
995 TAILQ_REMOVE(&vm_page_queues[PQ_INACTIVE].pl, m, pageq);
996 TAILQ_INSERT_TAIL(&vm_page_queues[PQ_INACTIVE].pl, m, pageq);
984263bc
MD
997 if (object->flags & OBJ_MIGHTBEDIRTY)
998 vnodes_skipped++;
999 vput(vp);
1000 continue;
1001 }
1002 }
1003
1004 /*
1005 * If a page is dirty, then it is either being washed
1006 * (but not yet cleaned) or it is still in the
1007 * laundry. If it is still in the laundry, then we
1008 * start the cleaning operation.
1009 *
1010 * This operation may cluster, invalidating the 'next'
1011 * pointer. To prevent an inordinate number of
1012 * restarts we use our marker to remember our place.
1013 *
1014 * decrement page_shortage on success to account for
1015 * the (future) cleaned page. Otherwise we could wind
1016 * up laundering or cleaning too many pages.
1017 */
984263bc 1018 TAILQ_INSERT_AFTER(&vm_page_queues[PQ_INACTIVE].pl, m, &marker, pageq);
984263bc
MD
1019 if (vm_pageout_clean(m) != 0) {
1020 --page_shortage;
1021 --maxlaunder;
c84c24da
MD
1022 } else {
1023 addl_page_shortage++;
1024 }
984263bc
MD
1025 next = TAILQ_NEXT(&marker, pageq);
1026 TAILQ_REMOVE(&vm_page_queues[PQ_INACTIVE].pl, &marker, pageq);
984263bc
MD
1027 if (vp != NULL)
1028 vput(vp);
1029 }
1030 }
1031
1032 /*
1033 * Compute the number of pages we want to try to move from the
1034 * active queue to the inactive queue.
1035 */
1036 page_shortage = vm_paging_target() +
c84c24da 1037 vmstats.v_inactive_target - vmstats.v_inactive_count;
984263bc
MD
1038 page_shortage += addl_page_shortage;
1039
c84c24da
MD
1040 /*
1041 * If the system is running out of swap or has none a large backlog
1042 * can accumulate in the inactive list. Continue moving pages to
1043 * the inactive list even though its 'target' has been met due to
1044 * being unable to drain. We can then use a low active count to
1045 * measure stress and out-of-memory conditions.
1046 */
1047 if (page_shortage < addl_page_shortage)
1048 page_shortage = addl_page_shortage;
1049
984263bc
MD
1050 /*
1051 * Scan the active queue for things we can deactivate. We nominally
1052 * track the per-page activity counter and use it to locate
1053 * deactivation candidates.
06ecca5a 1054 *
5fd012e0 1055 * NOTE: we are still in a critical section.
984263bc 1056 */
12e4aaff 1057 pcount = vmstats.v_active_count;
984263bc
MD
1058 m = TAILQ_FIRST(&vm_page_queues[PQ_ACTIVE].pl);
1059
1060 while ((m != NULL) && (pcount-- > 0) && (page_shortage > 0)) {
06ecca5a
MD
1061 /*
1062 * Give interrupts a chance.
1063 */
5fd012e0
MD
1064 crit_exit();
1065 crit_enter();
984263bc
MD
1066
1067 /*
06ecca5a 1068 * If the page was ripped out from under us, just stop.
984263bc 1069 */
06ecca5a 1070 if (m->queue != PQ_ACTIVE)
984263bc 1071 break;
984263bc 1072 next = TAILQ_NEXT(m, pageq);
06ecca5a 1073
984263bc
MD
1074 /*
1075 * Don't deactivate pages that are busy.
1076 */
1077 if ((m->busy != 0) ||
1078 (m->flags & PG_BUSY) ||
1079 (m->hold_count != 0)) {
984263bc
MD
1080 TAILQ_REMOVE(&vm_page_queues[PQ_ACTIVE].pl, m, pageq);
1081 TAILQ_INSERT_TAIL(&vm_page_queues[PQ_ACTIVE].pl, m, pageq);
984263bc
MD
1082 m = next;
1083 continue;
1084 }
1085
1086 /*
1087 * The count for pagedaemon pages is done after checking the
1088 * page for eligibility...
1089 */
12e4aaff 1090 mycpu->gd_cnt.v_pdpages++;
984263bc
MD
1091
1092 /*
1093 * Check to see "how much" the page has been used.
1094 */
1095 actcount = 0;
1096 if (m->object->ref_count != 0) {
1097 if (m->flags & PG_REFERENCED) {
1098 actcount += 1;
1099 }
1100 actcount += pmap_ts_referenced(m);
1101 if (actcount) {
1102 m->act_count += ACT_ADVANCE + actcount;
1103 if (m->act_count > ACT_MAX)
1104 m->act_count = ACT_MAX;
1105 }
1106 }
1107
1108 /*
1109 * Since we have "tested" this bit, we need to clear it now.
1110 */
1111 vm_page_flag_clear(m, PG_REFERENCED);
1112
1113 /*
1114 * Only if an object is currently being used, do we use the
1115 * page activation count stats.
1116 */
1117 if (actcount && (m->object->ref_count != 0)) {
984263bc
MD
1118 TAILQ_REMOVE(&vm_page_queues[PQ_ACTIVE].pl, m, pageq);
1119 TAILQ_INSERT_TAIL(&vm_page_queues[PQ_ACTIVE].pl, m, pageq);
984263bc
MD
1120 } else {
1121 m->act_count -= min(m->act_count, ACT_DECLINE);
1122 if (vm_pageout_algorithm ||
1123 m->object->ref_count == 0 ||
b5ccee96 1124 m->act_count < pass) {
984263bc
MD
1125 page_shortage--;
1126 if (m->object->ref_count == 0) {
17cde63e 1127 vm_page_busy(m);
984263bc 1128 vm_page_protect(m, VM_PROT_NONE);
17cde63e 1129 vm_page_wakeup(m);
c84c24da
MD
1130 if (m->dirty == 0) {
1131 ++pages_freed;
984263bc 1132 vm_page_cache(m);
c84c24da 1133 } else {
984263bc 1134 vm_page_deactivate(m);
c84c24da 1135 }
984263bc
MD
1136 } else {
1137 vm_page_deactivate(m);
1138 }
1139 } else {
984263bc
MD
1140 TAILQ_REMOVE(&vm_page_queues[PQ_ACTIVE].pl, m, pageq);
1141 TAILQ_INSERT_TAIL(&vm_page_queues[PQ_ACTIVE].pl, m, pageq);
984263bc
MD
1142 }
1143 }
1144 m = next;
1145 }
1146
984263bc
MD
1147 /*
1148 * We try to maintain some *really* free pages, this allows interrupt
1149 * code to be guaranteed space. Since both cache and free queues
1150 * are considered basically 'free', moving pages from cache to free
1151 * does not effect other calculations.
06ecca5a 1152 *
5fd012e0 1153 * NOTE: we are still in a critical section.
c84c24da
MD
1154 *
1155 * Pages moved from PQ_CACHE to totally free are not counted in the
1156 * pages_freed counter.
984263bc
MD
1157 */
1158
12e4aaff 1159 while (vmstats.v_free_count < vmstats.v_free_reserved) {
984263bc
MD
1160 static int cache_rover = 0;
1161 m = vm_page_list_find(PQ_CACHE, cache_rover, FALSE);
1162 if (!m)
1163 break;
1164 if ((m->flags & (PG_BUSY|PG_UNMANAGED)) ||
1165 m->busy ||
1166 m->hold_count ||
1167 m->wire_count) {
1168#ifdef INVARIANTS
086c1d7e 1169 kprintf("Warning: busy page %p found in cache\n", m);
984263bc
MD
1170#endif
1171 vm_page_deactivate(m);
1172 continue;
1173 }
17cde63e
MD
1174 KKASSERT((m->flags & PG_MAPPED) == 0);
1175 KKASSERT(m->dirty == 0);
984263bc
MD
1176 cache_rover = (cache_rover + PQ_PRIME2) & PQ_L2_MASK;
1177 vm_pageout_page_free(m);
12e4aaff 1178 mycpu->gd_cnt.v_dfree++;
984263bc 1179 }
06ecca5a 1180
5fd012e0 1181 crit_exit();
984263bc
MD
1182
1183#if !defined(NO_SWAPPING)
1184 /*
1185 * Idle process swapout -- run once per second.
1186 */
1187 if (vm_swap_idle_enabled) {
1188 static long lsec;
1189 if (time_second != lsec) {
1190 vm_pageout_req_swapout |= VM_SWAP_IDLE;
1191 vm_req_vmdaemon();
1192 lsec = time_second;
1193 }
1194 }
1195#endif
1196
1197 /*
1198 * If we didn't get enough free pages, and we have skipped a vnode
1199 * in a writeable object, wakeup the sync daemon. And kick swapout
1200 * if we did not get enough free pages.
1201 */
1202 if (vm_paging_target() > 0) {
1203 if (vnodes_skipped && vm_page_count_min())
418ff780 1204 speedup_syncer();
984263bc
MD
1205#if !defined(NO_SWAPPING)
1206 if (vm_swap_enabled && vm_page_count_target()) {
1207 vm_req_vmdaemon();
1208 vm_pageout_req_swapout |= VM_SWAP_NORMAL;
1209 }
1210#endif
1211 }
1212
1213 /*
c84c24da
MD
1214 * If we are out of swap space (or have no swap) then we
1215 * can detect when the system has completely run out of
1216 * memory by observing several variables.
1217 *
1218 * - swap_pager_full is set if insufficient swap was
1219 * available to satisfy a requested pageout.
1220 *
1221 * - vm_page_count_min() means we could not recover
1222 * enough pages to meet bare minimum needs.
1223 *
1224 * - vm_active_count
1225 *
1226 *and we were
1227 * not able to reach our minimum free page count target,
1228 * then we can detect whether we have run out of memory
1229 * by observing the active count. A memory starved
1230 * system will reduce the active count
1231 *
1232 * If under these circumstances our paging target exceeds
1233 * 1/2 the number of active pages we have a very serious
1234 * problem that the deactivation of pages failed to solve
1235 * and must start killing things.
984263bc 1236 */
c84c24da
MD
1237 if (swap_pager_full && vm_page_count_min())
1238 kprintf("Warning: system low on memory+swap!\n");
1239 if (swap_pager_full && vm_page_count_min() &&
1240 vm_paging_target() > vmstats.v_active_count / 4) {
8fa76237
MD
1241 info.bigproc = NULL;
1242 info.bigsize = 0;
1243 allproc_scan(vm_pageout_scan_callback, &info);
1244 if (info.bigproc != NULL) {
1245 killproc(info.bigproc, "out of swap space");
1246 info.bigproc->p_nice = PRIO_MIN;
08f2f1bb
SS
1247 info.bigproc->p_usched->resetpriority(
1248 FIRST_LWP_IN_PROC(info.bigproc));
12e4aaff 1249 wakeup(&vmstats.v_free_count);
8fa76237 1250 PRELE(info.bigproc);
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1251 }
1252 }
1253}
1254
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1255static int
1256vm_pageout_scan_callback(struct proc *p, void *data)
1257{
1258 struct vm_pageout_scan_info *info = data;
1259 vm_offset_t size;
1260
1261 /*
1262 * if this is a system process, skip it
1263 */
1264 if ((p->p_flag & P_SYSTEM) || (p->p_pid == 1) ||
1265 ((p->p_pid < 48) && (vm_swap_size != 0))) {
1266 return (0);
1267 }
1268
1269 /*
1270 * if the process is in a non-running type state,
1271 * don't touch it.
1272 */
164b8401 1273 if (p->p_stat != SACTIVE && p->p_stat != SSTOP) {
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1274 return (0);
1275 }
1276
1277 /*
1278 * get the process size
1279 */
1280 size = vmspace_resident_count(p->p_vmspace) +
1281 vmspace_swap_count(p->p_vmspace);
1282
1283 /*
1284 * If the this process is bigger than the biggest one
1285 * remember it.
1286 */
1287 if (size > info->bigsize) {
1288 if (info->bigproc)
1289 PRELE(info->bigproc);
1290 PHOLD(p);
1291 info->bigproc = p;
1292 info->bigsize = size;
1293 }
1294 return(0);
1295}
1296
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1297/*
1298 * This routine tries to maintain the pseudo LRU active queue,
1299 * so that during long periods of time where there is no paging,
1300 * that some statistic accumulation still occurs. This code
1301 * helps the situation where paging just starts to occur.
1302 */
1303static void
57e43348 1304vm_pageout_page_stats(void)
984263bc 1305{
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1306 vm_page_t m,next;
1307 int pcount,tpcount; /* Number of pages to check */
1308 static int fullintervalcount = 0;
1309 int page_shortage;
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1310
1311 page_shortage =
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1312 (vmstats.v_inactive_target + vmstats.v_cache_max + vmstats.v_free_min) -
1313 (vmstats.v_free_count + vmstats.v_inactive_count + vmstats.v_cache_count);
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1314
1315 if (page_shortage <= 0)
1316 return;
1317
5fd012e0 1318 crit_enter();
984263bc 1319
12e4aaff 1320 pcount = vmstats.v_active_count;
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1321 fullintervalcount += vm_pageout_stats_interval;
1322 if (fullintervalcount < vm_pageout_full_stats_interval) {
12e4aaff 1323 tpcount = (vm_pageout_stats_max * vmstats.v_active_count) / vmstats.v_page_count;
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1324 if (pcount > tpcount)
1325 pcount = tpcount;
1326 } else {
1327 fullintervalcount = 0;
1328 }
1329
1330 m = TAILQ_FIRST(&vm_page_queues[PQ_ACTIVE].pl);
1331 while ((m != NULL) && (pcount-- > 0)) {
1332 int actcount;
1333
1334 if (m->queue != PQ_ACTIVE) {
1335 break;
1336 }
1337
1338 next = TAILQ_NEXT(m, pageq);
1339 /*
1340 * Don't deactivate pages that are busy.
1341 */
1342 if ((m->busy != 0) ||
1343 (m->flags & PG_BUSY) ||
1344 (m->hold_count != 0)) {
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1345 TAILQ_REMOVE(&vm_page_queues[PQ_ACTIVE].pl, m, pageq);
1346 TAILQ_INSERT_TAIL(&vm_page_queues[PQ_ACTIVE].pl, m, pageq);
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1347 m = next;
1348 continue;
1349 }
1350
1351 actcount = 0;
1352 if (m->flags & PG_REFERENCED) {
1353 vm_page_flag_clear(m, PG_REFERENCED);
1354 actcount += 1;
1355 }
1356
1357 actcount += pmap_ts_referenced(m);
1358 if (actcount) {
1359 m->act_count += ACT_ADVANCE + actcount;
1360 if (m->act_count > ACT_MAX)
1361 m->act_count = ACT_MAX;
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1362 TAILQ_REMOVE(&vm_page_queues[PQ_ACTIVE].pl, m, pageq);
1363 TAILQ_INSERT_TAIL(&vm_page_queues[PQ_ACTIVE].pl, m, pageq);
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1364 } else {
1365 if (m->act_count == 0) {
1366 /*
1367 * We turn off page access, so that we have
1368 * more accurate RSS stats. We don't do this
1369 * in the normal page deactivation when the
1370 * system is loaded VM wise, because the
1371 * cost of the large number of page protect
1372 * operations would be higher than the value
1373 * of doing the operation.
1374 */
17cde63e 1375 vm_page_busy(m);
984263bc 1376 vm_page_protect(m, VM_PROT_NONE);
17cde63e 1377 vm_page_wakeup(m);
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1378 vm_page_deactivate(m);
1379 } else {
1380 m->act_count -= min(m->act_count, ACT_DECLINE);
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1381 TAILQ_REMOVE(&vm_page_queues[PQ_ACTIVE].pl, m, pageq);
1382 TAILQ_INSERT_TAIL(&vm_page_queues[PQ_ACTIVE].pl, m, pageq);
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1383 }
1384 }
1385
1386 m = next;
1387 }
5fd012e0 1388 crit_exit();
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1389}
1390
1391static int
57e43348 1392vm_pageout_free_page_calc(vm_size_t count)
984263bc 1393{
12e4aaff 1394 if (count < vmstats.v_page_count)
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1395 return 0;
1396 /*
1397 * free_reserved needs to include enough for the largest swap pager
1398 * structures plus enough for any pv_entry structs when paging.
1399 */
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1400 if (vmstats.v_page_count > 1024)
1401 vmstats.v_free_min = 4 + (vmstats.v_page_count - 1024) / 200;
984263bc 1402 else
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1403 vmstats.v_free_min = 4;
1404 vmstats.v_pageout_free_min = (2*MAXBSIZE)/PAGE_SIZE +
1405 vmstats.v_interrupt_free_min;
1406 vmstats.v_free_reserved = vm_pageout_page_count +
1407 vmstats.v_pageout_free_min + (count / 768) + PQ_L2_SIZE;
1408 vmstats.v_free_severe = vmstats.v_free_min / 2;
1409 vmstats.v_free_min += vmstats.v_free_reserved;
1410 vmstats.v_free_severe += vmstats.v_free_reserved;
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1411 return 1;
1412}
1413
1414
1415/*
1416 * vm_pageout is the high level pageout daemon.
1417 */
1418static void
57e43348 1419vm_pageout(void)
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1420{
1421 int pass;
1422
1423 /*
1424 * Initialize some paging parameters.
1425 */
4ecf7cc9 1426 curthread->td_flags |= TDF_SYSTHREAD;
984263bc 1427
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1428 vmstats.v_interrupt_free_min = 2;
1429 if (vmstats.v_page_count < 2000)
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1430 vm_pageout_page_count = 8;
1431
12e4aaff 1432 vm_pageout_free_page_calc(vmstats.v_page_count);
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1433 /*
1434 * v_free_target and v_cache_min control pageout hysteresis. Note
1435 * that these are more a measure of the VM cache queue hysteresis
1436 * then the VM free queue. Specifically, v_free_target is the
1437 * high water mark (free+cache pages).
1438 *
1439 * v_free_reserved + v_cache_min (mostly means v_cache_min) is the
1440 * low water mark, while v_free_min is the stop. v_cache_min must
1441 * be big enough to handle memory needs while the pageout daemon
1442 * is signalled and run to free more pages.
1443 */
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1444 if (vmstats.v_free_count > 6144)
1445 vmstats.v_free_target = 4 * vmstats.v_free_min + vmstats.v_free_reserved;
984263bc 1446 else
12e4aaff 1447 vmstats.v_free_target = 2 * vmstats.v_free_min + vmstats.v_free_reserved;
984263bc 1448
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1449 if (vmstats.v_free_count > 2048) {
1450 vmstats.v_cache_min = vmstats.v_free_target;
1451 vmstats.v_cache_max = 2 * vmstats.v_cache_min;
1452 vmstats.v_inactive_target = (3 * vmstats.v_free_target) / 2;
984263bc 1453 } else {
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1454 vmstats.v_cache_min = 0;
1455 vmstats.v_cache_max = 0;
1456 vmstats.v_inactive_target = vmstats.v_free_count / 4;
984263bc 1457 }
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1458 if (vmstats.v_inactive_target > vmstats.v_free_count / 3)
1459 vmstats.v_inactive_target = vmstats.v_free_count / 3;
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1460
1461 /* XXX does not really belong here */
1462 if (vm_page_max_wired == 0)
12e4aaff 1463 vm_page_max_wired = vmstats.v_free_count / 3;
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1464
1465 if (vm_pageout_stats_max == 0)
12e4aaff 1466 vm_pageout_stats_max = vmstats.v_free_target;
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1467
1468 /*
1469 * Set interval in seconds for stats scan.
1470 */
1471 if (vm_pageout_stats_interval == 0)
1472 vm_pageout_stats_interval = 5;
1473 if (vm_pageout_full_stats_interval == 0)
1474 vm_pageout_full_stats_interval = vm_pageout_stats_interval * 4;
1475
1476
1477 /*
1478 * Set maximum free per pass
1479 */
1480 if (vm_pageout_stats_free_max == 0)
1481 vm_pageout_stats_free_max = 5;
1482
1483 swap_pager_swap_init();
1484 pass = 0;
1485 /*
1486 * The pageout daemon is never done, so loop forever.
1487 */
1488 while (TRUE) {
1489 int error;
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1490
1491 /*
1492 * If we have enough free memory, wakeup waiters. Do
1493 * not clear vm_pages_needed until we reach our target,
1494 * otherwise we may be woken up over and over again and
1495 * waste a lot of cpu.
1496 */
5fd012e0 1497 crit_enter();
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1498 if (vm_pages_needed && !vm_page_count_min()) {
1499 if (vm_paging_needed() <= 0)
1500 vm_pages_needed = 0;
12e4aaff 1501 wakeup(&vmstats.v_free_count);
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1502 }
1503 if (vm_pages_needed) {
1504 /*
1505 * Still not done, take a second pass without waiting
1506 * (unlimited dirty cleaning), otherwise sleep a bit
1507 * and try again.
1508 */
1509 ++pass;
1510 if (pass > 1)
377d4740 1511 tsleep(&vm_pages_needed, 0, "psleep", hz/2);
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1512 } else {
1513 /*
1514 * Good enough, sleep & handle stats. Prime the pass
1515 * for the next run.
1516 */
1517 if (pass > 1)
1518 pass = 1;
1519 else
1520 pass = 0;
1521 error = tsleep(&vm_pages_needed,
377d4740 1522 0, "psleep", vm_pageout_stats_interval * hz);
984263bc 1523 if (error && !vm_pages_needed) {
5fd012e0 1524 crit_exit();
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1525 pass = 0;
1526 vm_pageout_page_stats();
1527 continue;
1528 }
1529 }
1530
1531 if (vm_pages_needed)
12e4aaff 1532 mycpu->gd_cnt.v_pdwakeups++;
5fd012e0 1533 crit_exit();
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1534 vm_pageout_scan(pass);
1535 vm_pageout_deficit = 0;
1536 }
1537}
1538
1539void
57e43348 1540pagedaemon_wakeup(void)
984263bc 1541{
bc6dffab 1542 if (!vm_pages_needed && curthread != pagethread) {
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1543 vm_pages_needed++;
1544 wakeup(&vm_pages_needed);
1545 }
1546}
1547
1548#if !defined(NO_SWAPPING)
1549static void
57e43348 1550vm_req_vmdaemon(void)
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1551{
1552 static int lastrun = 0;
1553
1554 if ((ticks > (lastrun + hz)) || (ticks < lastrun)) {
1555 wakeup(&vm_daemon_needed);
1556 lastrun = ticks;
1557 }
1558}
1559
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1560static int vm_daemon_callback(struct proc *p, void *data __unused);
1561
984263bc 1562static void
57e43348 1563vm_daemon(void)
984263bc 1564{
984263bc 1565 while (TRUE) {
377d4740 1566 tsleep(&vm_daemon_needed, 0, "psleep", 0);
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1567 if (vm_pageout_req_swapout) {
1568 swapout_procs(vm_pageout_req_swapout);
1569 vm_pageout_req_swapout = 0;
1570 }
1571 /*
1572 * scan the processes for exceeding their rlimits or if
1573 * process is swapped out -- deactivate pages
1574 */
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1575 allproc_scan(vm_daemon_callback, NULL);
1576 }
1577}
984263bc 1578
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1579static int
1580vm_daemon_callback(struct proc *p, void *data __unused)
1581{
1582 vm_pindex_t limit, size;
984263bc 1583
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1584 /*
1585 * if this is a system process or if we have already
1586 * looked at this process, skip it.
1587 */
1588 if (p->p_flag & (P_SYSTEM | P_WEXIT))
1589 return (0);
984263bc 1590
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1591 /*
1592 * if the process is in a non-running type state,
1593 * don't touch it.
1594 */
164b8401 1595 if (p->p_stat != SACTIVE && p->p_stat != SSTOP)
8fa76237 1596 return (0);
984263bc 1597
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1598 /*
1599 * get a limit
1600 */
1601 limit = OFF_TO_IDX(qmin(p->p_rlimit[RLIMIT_RSS].rlim_cur,
1602 p->p_rlimit[RLIMIT_RSS].rlim_max));
1603
1604 /*
1605 * let processes that are swapped out really be
1606 * swapped out. Set the limit to nothing to get as
1607 * many pages out to swap as possible.
1608 */
1609 if (p->p_flag & P_SWAPPEDOUT)
1610 limit = 0;
1611
1612 size = vmspace_resident_count(p->p_vmspace);
1613 if (limit >= 0 && size >= limit) {
1614 vm_pageout_map_deactivate_pages(
1615 &p->p_vmspace->vm_map, limit);
984263bc 1616 }
8fa76237 1617 return (0);
984263bc 1618}
8fa76237 1619
984263bc 1620#endif