FreeBSD virtual memory subsystem code
vm_pageout.c
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1/*-
2 * SPDX-License-Identifier: (BSD-4-Clause AND MIT-CMU)
3 *
4 * Copyright (c) 1991 Regents of the University of California.
5 * All rights reserved.
6 * Copyright (c) 1994 John S. Dyson
7 * All rights reserved.
8 * Copyright (c) 1994 David Greenman
9 * All rights reserved.
10 * Copyright (c) 2005 Yahoo! Technologies Norway AS
11 * All rights reserved.
12 *
13 * This code is derived from software contributed to Berkeley by
14 * The Mach Operating System project at Carnegie-Mellon University.
15 *
16 * Redistribution and use in source and binary forms, with or without
17 * modification, are permitted provided that the following conditions
18 * are met:
19 * 1. Redistributions of source code must retain the above copyright
20 * notice, this list of conditions and the following disclaimer.
21 * 2. Redistributions in binary form must reproduce the above copyright
22 * notice, this list of conditions and the following disclaimer in the
23 * documentation and/or other materials provided with the distribution.
24 * 3. All advertising materials mentioning features or use of this software
25 * must display the following acknowledgement:
26 * This product includes software developed by the University of
27 * California, Berkeley and its contributors.
28 * 4. Neither the name of the University nor the names of its contributors
29 * may be used to endorse or promote products derived from this software
30 * without specific prior written permission.
31 *
32 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
33 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
34 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
35 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
36 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
37 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
38 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
39 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
40 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
41 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
42 * SUCH DAMAGE.
43 *
44 * from: @(#)vm_pageout.c 7.4 (Berkeley) 5/7/91
45 *
46 *
47 * Copyright (c) 1987, 1990 Carnegie-Mellon University.
48 * All rights reserved.
49 *
50 * Authors: Avadis Tevanian, Jr., Michael Wayne Young
51 *
52 * Permission to use, copy, modify and distribute this software and
53 * its documentation is hereby granted, provided that both the copyright
54 * notice and this permission notice appear in all copies of the
55 * software, derivative works or modified versions, and any portions
56 * thereof, and that both notices appear in supporting documentation.
57 *
58 * CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS"
59 * CONDITION. CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND
60 * FOR ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
61 *
62 * Carnegie Mellon requests users of this software to return to
63 *
64 * Software Distribution Coordinator or Software.Distribution@CS.CMU.EDU
65 * School of Computer Science
66 * Carnegie Mellon University
67 * Pittsburgh PA 15213-3890
68 *
69 * any improvements or extensions that they make and grant Carnegie the
70 * rights to redistribute these changes.
71 */
72
73/*
74 * The proverbial page-out daemon.
75 */
76
77#include <sys/cdefs.h>
78__FBSDID("$FreeBSD$");
79
80#include "opt_vm.h"
81
82#include <sys/param.h>
83#include <sys/systm.h>
84#include <sys/kernel.h>
85#include <sys/blockcount.h>
86#include <sys/eventhandler.h>
87#include <sys/lock.h>
88#include <sys/mutex.h>
89#include <sys/proc.h>
90#include <sys/kthread.h>
91#include <sys/ktr.h>
92#include <sys/mount.h>
93#include <sys/racct.h>
94#include <sys/resourcevar.h>
95#include <sys/sched.h>
96#include <sys/sdt.h>
97#include <sys/signalvar.h>
98#include <sys/smp.h>
99#include <sys/time.h>
100#include <sys/vnode.h>
101#include <sys/vmmeter.h>
102#include <sys/rwlock.h>
103#include <sys/sx.h>
104#include <sys/sysctl.h>
105
106#include <vm/vm.h>
107#include <vm/vm_param.h>
108#include <vm/vm_object.h>
109#include <vm/vm_page.h>
110#include <vm/vm_map.h>
111#include <vm/vm_pageout.h>
112#include <vm/vm_pager.h>
113#include <vm/vm_phys.h>
114#include <vm/vm_pagequeue.h>
115#include <vm/swap_pager.h>
116#include <vm/vm_extern.h>
117#include <vm/uma.h>
118
119/*
120 * System initialization
121 */
122
123/* the kernel process "vm_pageout"*/
124static void vm_pageout(void);
125static void vm_pageout_init(void);
126static int vm_pageout_clean(vm_page_t m, int *numpagedout);
127static int vm_pageout_cluster(vm_page_t m);
128static void vm_pageout_mightbe_oom(struct vm_domain *vmd, int page_shortage,
129 int starting_page_shortage);
130
131SYSINIT(pagedaemon_init, SI_SUB_KTHREAD_PAGE, SI_ORDER_FIRST, vm_pageout_init,
132 NULL);
133
134struct proc *pageproc;
135
136static struct kproc_desc page_kp = {
137 "pagedaemon",
139 &pageproc
140};
141SYSINIT(pagedaemon, SI_SUB_KTHREAD_PAGE, SI_ORDER_SECOND, kproc_start,
142 &page_kp);
143
145SDT_PROBE_DEFINE(vm, , , vm__lowmem_scan);
146
147/* Pagedaemon activity rates, in subdivisions of one second. */
148#define VM_LAUNDER_RATE 10
149#define VM_INACT_SCAN_RATE 10
150
153
154static int vm_panic_on_oom = 0;
155SYSCTL_INT(_vm, OID_AUTO, panic_on_oom,
156 CTLFLAG_RWTUN, &vm_panic_on_oom, 0,
157 "Panic on the given number of out-of-memory errors instead of "
158 "killing the largest process");
159
161SYSCTL_INT(_vm, OID_AUTO, pageout_update_period,
162 CTLFLAG_RWTUN, &vm_pageout_update_period, 0,
163 "Maximum active LRU update period");
164
166SYSCTL_INT(_vm, OID_AUTO, pageout_cpus_per_thread, CTLFLAG_RDTUN,
168 "Number of CPUs per pagedaemon worker thread");
169
170static int lowmem_period = 10;
171SYSCTL_INT(_vm, OID_AUTO, lowmem_period, CTLFLAG_RWTUN, &lowmem_period, 0,
172 "Low memory callback period");
173
175SYSCTL_INT(_vm, OID_AUTO, disable_swapspace_pageouts,
176 CTLFLAG_RWTUN, &disable_swap_pageouts, 0,
177 "Disallow swapout of dirty pages");
178
181 CTLFLAG_RD, &pageout_lock_miss, 0,
182 "vget() lock misses during pageout");
183
184static int vm_pageout_oom_seq = 12;
185SYSCTL_INT(_vm, OID_AUTO, pageout_oom_seq,
186 CTLFLAG_RWTUN, &vm_pageout_oom_seq, 0,
187 "back-to-back calls to oom detector to start OOM");
188
190SYSCTL_INT(_vm, OID_AUTO, act_scan_laundry_weight, CTLFLAG_RWTUN,
192 "weight given to clean vs. dirty pages in active queue scans");
193
194static u_int vm_background_launder_rate = 4096;
195SYSCTL_UINT(_vm, OID_AUTO, background_launder_rate, CTLFLAG_RWTUN,
197 "background laundering rate, in kilobytes per second");
198
199static u_int vm_background_launder_max = 20 * 1024;
200SYSCTL_UINT(_vm, OID_AUTO, background_launder_max, CTLFLAG_RWTUN,
202 "background laundering cap, in kilobytes");
203
205SYSCTL_ULONG(_vm, OID_AUTO, max_user_wired, CTLFLAG_RW,
207 "system-wide limit to user-wired page count");
208
209static u_int isqrt(u_int num);
210static int vm_pageout_launder(struct vm_domain *vmd, int launder,
211 bool in_shortfall);
212static void vm_pageout_laundry_worker(void *arg);
213
217 vm_page_t marker;
220};
221
222static void
224 vm_page_t marker, vm_page_t after, int maxscan)
225{
226
228 KASSERT((marker->a.flags & PGA_ENQUEUED) == 0,
229 ("marker %p already enqueued", marker));
230
231 if (after == NULL)
232 TAILQ_INSERT_HEAD(&pq->pq_pl, marker, plinks.q);
233 else
234 TAILQ_INSERT_AFTER(&pq->pq_pl, after, marker, plinks.q);
236
238 ss->pq = pq;
239 ss->marker = marker;
240 ss->maxscan = maxscan;
241 ss->scanned = 0;
243}
244
245static void
247{
248 struct vm_pagequeue *pq;
249
250 pq = ss->pq;
252 KASSERT((ss->marker->a.flags & PGA_ENQUEUED) != 0,
253 ("marker %p not enqueued", ss->marker));
254
255 TAILQ_REMOVE(&pq->pq_pl, ss->marker, plinks.q);
257 pq->pq_pdpages += ss->scanned;
258}
259
260/*
261 * Add a small number of queued pages to a batch queue for later processing
262 * without the corresponding queue lock held. The caller must have enqueued a
263 * marker page at the desired start point for the scan. Pages will be
264 * physically dequeued if the caller so requests. Otherwise, the returned
265 * batch may contain marker pages, and it is up to the caller to handle them.
266 *
267 * When processing the batch queue, vm_pageout_defer() must be used to
268 * determine whether the page has been logically dequeued since the batch was
269 * collected.
270 */
271static __always_inline void
272vm_pageout_collect_batch(struct scan_state *ss, const bool dequeue)
273{
274 struct vm_pagequeue *pq;
275 vm_page_t m, marker, n;
276
277 marker = ss->marker;
278 pq = ss->pq;
279
280 KASSERT((marker->a.flags & PGA_ENQUEUED) != 0,
281 ("marker %p not enqueued", ss->marker));
282
284 for (m = TAILQ_NEXT(marker, plinks.q); m != NULL &&
285 ss->scanned < ss->maxscan && ss->bq.bq_cnt < VM_BATCHQUEUE_SIZE;
286 m = n, ss->scanned++) {
287 n = TAILQ_NEXT(m, plinks.q);
288 if ((m->flags & PG_MARKER) == 0) {
289 KASSERT((m->a.flags & PGA_ENQUEUED) != 0,
290 ("page %p not enqueued", m));
291 KASSERT((m->flags & PG_FICTITIOUS) == 0,
292 ("Fictitious page %p cannot be in page queue", m));
293 KASSERT((m->oflags & VPO_UNMANAGED) == 0,
294 ("Unmanaged page %p cannot be in page queue", m));
295 } else if (dequeue)
296 continue;
297
298 (void)vm_batchqueue_insert(&ss->bq, m);
299 if (dequeue) {
300 TAILQ_REMOVE(&pq->pq_pl, m, plinks.q);
302 }
303 }
304 TAILQ_REMOVE(&pq->pq_pl, marker, plinks.q);
305 if (__predict_true(m != NULL))
306 TAILQ_INSERT_BEFORE(m, marker, plinks.q);
307 else
308 TAILQ_INSERT_TAIL(&pq->pq_pl, marker, plinks.q);
309 if (dequeue)
312}
313
314/*
315 * Return the next page to be scanned, or NULL if the scan is complete.
316 */
317static __always_inline vm_page_t
318vm_pageout_next(struct scan_state *ss, const bool dequeue)
319{
320
321 if (ss->bq.bq_cnt == 0)
322 vm_pageout_collect_batch(ss, dequeue);
323 return (vm_batchqueue_pop(&ss->bq));
324}
325
326/*
327 * Determine whether processing of a page should be deferred and ensure that any
328 * outstanding queue operations are processed.
329 */
330static __always_inline bool
331vm_pageout_defer(vm_page_t m, const uint8_t queue, const bool enqueued)
332{
334
335 as = vm_page_astate_load(m);
336 if (__predict_false(as.queue != queue ||
337 ((as.flags & PGA_ENQUEUED) != 0) != enqueued))
338 return (true);
339 if ((as.flags & PGA_QUEUE_OP_MASK) != 0) {
340 vm_page_pqbatch_submit(m, queue);
341 return (true);
342 }
343 return (false);
344}
345
346/*
347 * Scan for pages at adjacent offsets within the given page's object that are
348 * eligible for laundering, form a cluster of these pages and the given page,
349 * and launder that cluster.
350 */
351static int
353{
354 vm_object_t object;
355 vm_page_t mc[2 * vm_pageout_page_count], p, pb, ps;
356 vm_pindex_t pindex;
357 int ib, is, page_base, pageout_count;
358
359 object = m->object;
361 pindex = m->pindex;
362
364
365 mc[vm_pageout_page_count] = pb = ps = m;
366 pageout_count = 1;
367 page_base = vm_pageout_page_count;
368 ib = 1;
369 is = 1;
370
371 /*
372 * We can cluster only if the page is not clean, busy, or held, and
373 * the page is in the laundry queue.
374 *
375 * During heavy mmap/modification loads the pageout
376 * daemon can really fragment the underlying file
377 * due to flushing pages out of order and not trying to
378 * align the clusters (which leaves sporadic out-of-order
379 * holes). To solve this problem we do the reverse scan
380 * first and attempt to align our cluster, then do a
381 * forward scan if room remains.
382 */
383more:
384 while (ib != 0 && pageout_count < vm_pageout_page_count) {
385 if (ib > pindex) {
386 ib = 0;
387 break;
388 }
389 if ((p = vm_page_prev(pb)) == NULL ||
390 vm_page_tryxbusy(p) == 0) {
391 ib = 0;
392 break;
393 }
394 if (vm_page_wired(p)) {
395 ib = 0;
397 break;
398 }
400 if (p->dirty == 0) {
401 ib = 0;
403 break;
404 }
407 ib = 0;
408 break;
409 }
410 mc[--page_base] = pb = p;
411 ++pageout_count;
412 ++ib;
413
414 /*
415 * We are at an alignment boundary. Stop here, and switch
416 * directions. Do not clear ib.
417 */
418 if ((pindex - (ib - 1)) % vm_pageout_page_count == 0)
419 break;
420 }
421 while (pageout_count < vm_pageout_page_count &&
422 pindex + is < object->size) {
423 if ((p = vm_page_next(ps)) == NULL ||
424 vm_page_tryxbusy(p) == 0)
425 break;
426 if (vm_page_wired(p)) {
428 break;
429 }
431 if (p->dirty == 0) {
433 break;
434 }
437 break;
438 }
439 mc[page_base + pageout_count] = ps = p;
440 ++pageout_count;
441 ++is;
442 }
443
444 /*
445 * If we exhausted our forward scan, continue with the reverse scan
446 * when possible, even past an alignment boundary. This catches
447 * boundary conditions.
448 */
449 if (ib != 0 && pageout_count < vm_pageout_page_count)
450 goto more;
451
452 return (vm_pageout_flush(&mc[page_base], pageout_count,
453 VM_PAGER_PUT_NOREUSE, 0, NULL, NULL));
454}
455
456/*
457 * vm_pageout_flush() - launder the given pages
458 *
459 * The given pages are laundered. Note that we setup for the start of
460 * I/O ( i.e. busy the page ), mark it read-only, and bump the object
461 * reference count all in here rather then in the parent. If we want
462 * the parent to do more sophisticated things we may have to change
463 * the ordering.
464 *
465 * Returned runlen is the count of pages between mreq and first
466 * page after mreq with status VM_PAGER_AGAIN.
467 * *eio is set to TRUE if pager returned VM_PAGER_ERROR or VM_PAGER_FAIL
468 * for any page in runlen set.
469 */
470int
471vm_pageout_flush(vm_page_t *mc, int count, int flags, int mreq, int *prunlen,
472 boolean_t *eio)
473{
474 vm_object_t object = mc[0]->object;
475 int pageout_status[count];
476 int numpagedout = 0;
477 int i, runlen;
478
480
481 /*
482 * Initiate I/O. Mark the pages shared busy and verify that they're
483 * valid and read-only.
484 *
485 * We do not have to fixup the clean/dirty bits here... we can
486 * allow the pager to do it after the I/O completes.
487 *
488 * NOTE! mc[i]->dirty may be partial or fragmented due to an
489 * edge case with file fragments.
490 */
491 for (i = 0; i < count; i++) {
492 KASSERT(vm_page_all_valid(mc[i]),
493 ("vm_pageout_flush: partially invalid page %p index %d/%d",
494 mc[i], i, count));
495 KASSERT((mc[i]->a.flags & PGA_WRITEABLE) == 0,
496 ("vm_pageout_flush: writeable page %p", mc[i]));
498 }
499 vm_object_pip_add(object, count);
500
501 vm_pager_put_pages(object, mc, count, flags, pageout_status);
502
503 runlen = count - mreq;
504 if (eio != NULL)
505 *eio = FALSE;
506 for (i = 0; i < count; i++) {
507 vm_page_t mt = mc[i];
508
509 KASSERT(pageout_status[i] == VM_PAGER_PEND ||
510 !pmap_page_is_write_mapped(mt),
511 ("vm_pageout_flush: page %p is not write protected", mt));
512 switch (pageout_status[i]) {
513 case VM_PAGER_OK:
514 /*
515 * The page may have moved since laundering started, in
516 * which case it should be left alone.
517 */
518 if (vm_page_in_laundry(mt))
520 /* FALLTHROUGH */
521 case VM_PAGER_PEND:
522 numpagedout++;
523 break;
524 case VM_PAGER_BAD:
525 /*
526 * The page is outside the object's range. We pretend
527 * that the page out worked and clean the page, so the
528 * changes will be lost if the page is reclaimed by
529 * the page daemon.
530 */
531 vm_page_undirty(mt);
532 if (vm_page_in_laundry(mt))
534 break;
535 case VM_PAGER_ERROR:
536 case VM_PAGER_FAIL:
537 /*
538 * If the page couldn't be paged out to swap because the
539 * pager wasn't able to find space, place the page in
540 * the PQ_UNSWAPPABLE holding queue. This is an
541 * optimization that prevents the page daemon from
542 * wasting CPU cycles on pages that cannot be reclaimed
543 * because no swap device is configured.
544 *
545 * Otherwise, reactivate the page so that it doesn't
546 * clog the laundry and inactive queues. (We will try
547 * paging it out again later.)
548 */
549 if ((object->flags & OBJ_SWAP) != 0 &&
550 pageout_status[i] == VM_PAGER_FAIL) {
552 numpagedout++;
553 } else
555 if (eio != NULL && i >= mreq && i - mreq < runlen)
556 *eio = TRUE;
557 break;
558 case VM_PAGER_AGAIN:
559 if (i >= mreq && i - mreq < runlen)
560 runlen = i - mreq;
561 break;
562 }
563
564 /*
565 * If the operation is still going, leave the page busy to
566 * block all other accesses. Also, leave the paging in
567 * progress indicator set so that we don't attempt an object
568 * collapse.
569 */
570 if (pageout_status[i] != VM_PAGER_PEND) {
571 vm_object_pip_wakeup(object);
572 vm_page_sunbusy(mt);
573 }
574 }
575 if (prunlen != NULL)
576 *prunlen = runlen;
577 return (numpagedout);
578}
579
580static void
581vm_pageout_swapon(void *arg __unused, struct swdevt *sp __unused)
582{
583
584 atomic_store_rel_int(&swapdev_enabled, 1);
585}
586
587static void
588vm_pageout_swapoff(void *arg __unused, struct swdevt *sp __unused)
589{
590
591 if (swap_pager_nswapdev() == 1)
592 atomic_store_rel_int(&swapdev_enabled, 0);
593}
594
595/*
596 * Attempt to acquire all of the necessary locks to launder a page and
597 * then call through the clustering layer to PUTPAGES. Wait a short
598 * time for a vnode lock.
599 *
600 * Requires the page and object lock on entry, releases both before return.
601 * Returns 0 on success and an errno otherwise.
602 */
603static int
604vm_pageout_clean(vm_page_t m, int *numpagedout)
605{
606 struct vnode *vp;
607 struct mount *mp;
608 vm_object_t object;
609 vm_pindex_t pindex;
610 int error;
611
612 object = m->object;
614 error = 0;
615 vp = NULL;
616 mp = NULL;
617
618 /*
619 * The object is already known NOT to be dead. It
620 * is possible for the vget() to block the whole
621 * pageout daemon, but the new low-memory handling
622 * code should prevent it.
623 *
624 * We can't wait forever for the vnode lock, we might
625 * deadlock due to a vn_read() getting stuck in
626 * vm_wait while holding this vnode. We skip the
627 * vnode if we can't get it in a reasonable amount
628 * of time.
629 */
630 if (object->type == OBJT_VNODE) {
632 vp = object->handle;
633 if (vp->v_type == VREG &&
634 vn_start_write(vp, &mp, V_NOWAIT) != 0) {
635 mp = NULL;
636 error = EDEADLK;
637 goto unlock_all;
638 }
639 KASSERT(mp != NULL,
640 ("vp %p with NULL v_mount", vp));
642 pindex = m->pindex;
643 VM_OBJECT_WUNLOCK(object);
644 if (vget(vp, vn_lktype_write(NULL, vp) | LK_TIMELOCK) != 0) {
645 vp = NULL;
646 error = EDEADLK;
647 goto unlock_mp;
648 }
649 VM_OBJECT_WLOCK(object);
650
651 /*
652 * Ensure that the object and vnode were not disassociated
653 * while locks were dropped.
654 */
655 if (vp->v_object != object) {
656 error = ENOENT;
657 goto unlock_all;
658 }
659
660 /*
661 * While the object was unlocked, the page may have been:
662 * (1) moved to a different queue,
663 * (2) reallocated to a different object,
664 * (3) reallocated to a different offset, or
665 * (4) cleaned.
666 */
667 if (!vm_page_in_laundry(m) || m->object != object ||
668 m->pindex != pindex || m->dirty == 0) {
669 error = ENXIO;
670 goto unlock_all;
671 }
672
673 /*
674 * The page may have been busied while the object lock was
675 * released.
676 */
677 if (vm_page_tryxbusy(m) == 0) {
678 error = EBUSY;
679 goto unlock_all;
680 }
681 }
682
683 /*
684 * Remove all writeable mappings, failing if the page is wired.
685 */
686 if (!vm_page_try_remove_write(m)) {
688 error = EBUSY;
689 goto unlock_all;
690 }
691
692 /*
693 * If a page is dirty, then it is either being washed
694 * (but not yet cleaned) or it is still in the
695 * laundry. If it is still in the laundry, then we
696 * start the cleaning operation.
697 */
698 if ((*numpagedout = vm_pageout_cluster(m)) == 0)
699 error = EIO;
700
701unlock_all:
702 VM_OBJECT_WUNLOCK(object);
703
704unlock_mp:
705 if (mp != NULL) {
706 if (vp != NULL)
707 vput(vp);
708 vm_object_deallocate(object);
709 vn_finished_write(mp);
710 }
711
712 return (error);
713}
714
715/*
716 * Attempt to launder the specified number of pages.
717 *
718 * Returns the number of pages successfully laundered.
719 */
720static int
721vm_pageout_launder(struct vm_domain *vmd, int launder, bool in_shortfall)
722{
723 struct scan_state ss;
724 struct vm_pagequeue *pq;
725 vm_object_t object;
726 vm_page_t m, marker;
727 vm_page_astate_t new, old;
728 int act_delta, error, numpagedout, queue, refs, starting_target;
729 int vnodes_skipped;
730 bool pageout_ok;
731
732 object = NULL;
733 starting_target = launder;
734 vnodes_skipped = 0;
735
736 /*
737 * Scan the laundry queues for pages eligible to be laundered. We stop
738 * once the target number of dirty pages have been laundered, or once
739 * we've reached the end of the queue. A single iteration of this loop
740 * may cause more than one page to be laundered because of clustering.
741 *
742 * As an optimization, we avoid laundering from PQ_UNSWAPPABLE when no
743 * swap devices are configured.
744 */
745 if (atomic_load_acq_int(&swapdev_enabled))
746 queue = PQ_UNSWAPPABLE;
747 else
748 queue = PQ_LAUNDRY;
749
750scan:
751 marker = &vmd->vmd_markers[queue];
752 pq = &vmd->vmd_pagequeues[queue];
754 vm_pageout_init_scan(&ss, pq, marker, NULL, pq->pq_cnt);
755 while (launder > 0 && (m = vm_pageout_next(&ss, false)) != NULL) {
756 if (__predict_false((m->flags & PG_MARKER) != 0))
757 continue;
758
759 /*
760 * Don't touch a page that was removed from the queue after the
761 * page queue lock was released. Otherwise, ensure that any
762 * pending queue operations, such as dequeues for wired pages,
763 * are handled.
764 */
765 if (vm_pageout_defer(m, queue, true))
766 continue;
767
768 /*
769 * Lock the page's object.
770 */
771 if (object == NULL || object != m->object) {
772 if (object != NULL)
773 VM_OBJECT_WUNLOCK(object);
774 object = atomic_load_ptr(&m->object);
775 if (__predict_false(object == NULL))
776 /* The page is being freed by another thread. */
777 continue;
778
779 /* Depends on type-stability. */
780 VM_OBJECT_WLOCK(object);
781 if (__predict_false(m->object != object)) {
782 VM_OBJECT_WUNLOCK(object);
783 object = NULL;
784 continue;
785 }
786 }
787
788 if (vm_page_tryxbusy(m) == 0)
789 continue;
790
791 /*
792 * Check for wirings now that we hold the object lock and have
793 * exclusively busied the page. If the page is mapped, it may
794 * still be wired by pmap lookups. The call to
795 * vm_page_try_remove_all() below atomically checks for such
796 * wirings and removes mappings. If the page is unmapped, the
797 * wire count is guaranteed not to increase after this check.
798 */
799 if (__predict_false(vm_page_wired(m)))
800 goto skip_page;
801
802 /*
803 * Invalid pages can be easily freed. They cannot be
804 * mapped; vm_page_free() asserts this.
805 */
806 if (vm_page_none_valid(m))
807 goto free_page;
808
809 refs = object->ref_count != 0 ? pmap_ts_referenced(m) : 0;
810
811 for (old = vm_page_astate_load(m);;) {
812 /*
813 * Check to see if the page has been removed from the
814 * queue since the first such check. Leave it alone if
815 * so, discarding any references collected by
816 * pmap_ts_referenced().
817 */
818 if (__predict_false(_vm_page_queue(old) == PQ_NONE))
819 goto skip_page;
820
821 new = old;
822 act_delta = refs;
823 if ((old.flags & PGA_REFERENCED) != 0) {
824 new.flags &= ~PGA_REFERENCED;
825 act_delta++;
826 }
827 if (act_delta == 0) {
828 ;
829 } else if (object->ref_count != 0) {
830 /*
831 * Increase the activation count if the page was
832 * referenced while in the laundry queue. This
833 * makes it less likely that the page will be
834 * returned prematurely to the laundry queue.
835 */
836 new.act_count += ACT_ADVANCE +
837 act_delta;
838 if (new.act_count > ACT_MAX)
839 new.act_count = ACT_MAX;
840
841 new.flags &= ~PGA_QUEUE_OP_MASK;
842 new.flags |= PGA_REQUEUE;
843 new.queue = PQ_ACTIVE;
844 if (!vm_page_pqstate_commit(m, &old, new))
845 continue;
846
847 /*
848 * If this was a background laundering, count
849 * activated pages towards our target. The
850 * purpose of background laundering is to ensure
851 * that pages are eventually cycled through the
852 * laundry queue, and an activation is a valid
853 * way out.
854 */
855 if (!in_shortfall)
856 launder--;
857 VM_CNT_INC(v_reactivated);
858 goto skip_page;
859 } else if ((object->flags & OBJ_DEAD) == 0) {
860 new.flags |= PGA_REQUEUE;
861 if (!vm_page_pqstate_commit(m, &old, new))
862 continue;
863 goto skip_page;
864 }
865 break;
866 }
867
868 /*
869 * If the page appears to be clean at the machine-independent
870 * layer, then remove all of its mappings from the pmap in
871 * anticipation of freeing it. If, however, any of the page's
872 * mappings allow write access, then the page may still be
873 * modified until the last of those mappings are removed.
874 */
875 if (object->ref_count != 0) {
877 if (m->dirty == 0 && !vm_page_try_remove_all(m))
878 goto skip_page;
879 }
880
881 /*
882 * Clean pages are freed, and dirty pages are paged out unless
883 * they belong to a dead object. Requeueing dirty pages from
884 * dead objects is pointless, as they are being paged out and
885 * freed by the thread that destroyed the object.
886 */
887 if (m->dirty == 0) {
888free_page:
889 /*
890 * Now we are guaranteed that no other threads are
891 * manipulating the page, check for a last-second
892 * reference.
893 */
894 if (vm_pageout_defer(m, queue, true))
895 goto skip_page;
896 vm_page_free(m);
897 VM_CNT_INC(v_dfree);
898 } else if ((object->flags & OBJ_DEAD) == 0) {
899 if ((object->flags & OBJ_SWAP) == 0 &&
900 object->type != OBJT_DEFAULT)
901 pageout_ok = true;
902 else if (disable_swap_pageouts)
903 pageout_ok = false;
904 else
905 pageout_ok = true;
906 if (!pageout_ok) {
908 goto skip_page;
909 }
910
911 /*
912 * Form a cluster with adjacent, dirty pages from the
913 * same object, and page out that entire cluster.
914 *
915 * The adjacent, dirty pages must also be in the
916 * laundry. However, their mappings are not checked
917 * for new references. Consequently, a recently
918 * referenced page may be paged out. However, that
919 * page will not be prematurely reclaimed. After page
920 * out, the page will be placed in the inactive queue,
921 * where any new references will be detected and the
922 * page reactivated.
923 */
924 error = vm_pageout_clean(m, &numpagedout);
925 if (error == 0) {
926 launder -= numpagedout;
927 ss.scanned += numpagedout;
928 } else if (error == EDEADLK) {
930 vnodes_skipped++;
931 }
932 object = NULL;
933 } else {
934skip_page:
936 }
937 }
938 if (object != NULL) {
939 VM_OBJECT_WUNLOCK(object);
940 object = NULL;
941 }
945
946 if (launder > 0 && queue == PQ_UNSWAPPABLE) {
947 queue = PQ_LAUNDRY;
948 goto scan;
949 }
950
951 /*
952 * Wakeup the sync daemon if we skipped a vnode in a writeable object
953 * and we didn't launder enough pages.
954 */
955 if (vnodes_skipped > 0 && launder > 0)
956 (void)speedup_syncer();
957
958 return (starting_target - launder);
959}
960
961/*
962 * Compute the integer square root.
963 */
964static u_int
965isqrt(u_int num)
966{
967 u_int bit, root, tmp;
968
969 bit = num != 0 ? (1u << ((fls(num) - 1) & ~1)) : 0;
970 root = 0;
971 while (bit != 0) {
972 tmp = root + bit;
973 root >>= 1;
974 if (num >= tmp) {
975 num -= tmp;
976 root += bit;
977 }
978 bit >>= 2;
979 }
980 return (root);
981}
982
983/*
984 * Perform the work of the laundry thread: periodically wake up and determine
985 * whether any pages need to be laundered. If so, determine the number of pages
986 * that need to be laundered, and launder them.
987 */
988static void
990{
991 struct vm_domain *vmd;
992 struct vm_pagequeue *pq;
993 uint64_t nclean, ndirty, nfreed;
994 int domain, last_target, launder, shortfall, shortfall_cycle, target;
995 bool in_shortfall;
996
997 domain = (uintptr_t)arg;
998 vmd = VM_DOMAIN(domain);
999 pq = &vmd->vmd_pagequeues[PQ_LAUNDRY];
1000 KASSERT(vmd->vmd_segs != 0, ("domain without segments"));
1001
1002 shortfall = 0;
1003 in_shortfall = false;
1004 shortfall_cycle = 0;
1005 last_target = target = 0;
1006 nfreed = 0;
1007
1008 /*
1009 * Calls to these handlers are serialized by the swap syscall lock.
1010 */
1011 (void)EVENTHANDLER_REGISTER(swapon, vm_pageout_swapon, vmd,
1012 EVENTHANDLER_PRI_ANY);
1013 (void)EVENTHANDLER_REGISTER(swapoff, vm_pageout_swapoff, vmd,
1014 EVENTHANDLER_PRI_ANY);
1015
1016 /*
1017 * The pageout laundry worker is never done, so loop forever.
1018 */
1019 for (;;) {
1020 KASSERT(target >= 0, ("negative target %d", target));
1021 KASSERT(shortfall_cycle >= 0,
1022 ("negative cycle %d", shortfall_cycle));
1023 launder = 0;
1024
1025 /*
1026 * First determine whether we need to launder pages to meet a
1027 * shortage of free pages.
1028 */
1029 if (shortfall > 0) {
1030 in_shortfall = true;
1031 shortfall_cycle = VM_LAUNDER_RATE / VM_INACT_SCAN_RATE;
1032 target = shortfall;
1033 } else if (!in_shortfall)
1034 goto trybackground;
1035 else if (shortfall_cycle == 0 || vm_laundry_target(vmd) <= 0) {
1036 /*
1037 * We recently entered shortfall and began laundering
1038 * pages. If we have completed that laundering run
1039 * (and we are no longer in shortfall) or we have met
1040 * our laundry target through other activity, then we
1041 * can stop laundering pages.
1042 */
1043 in_shortfall = false;
1044 target = 0;
1045 goto trybackground;
1046 }
1047 launder = target / shortfall_cycle--;
1048 goto dolaundry;
1049
1050 /*
1051 * There's no immediate need to launder any pages; see if we
1052 * meet the conditions to perform background laundering:
1053 *
1054 * 1. The ratio of dirty to clean inactive pages exceeds the
1055 * background laundering threshold, or
1056 * 2. we haven't yet reached the target of the current
1057 * background laundering run.
1058 *
1059 * The background laundering threshold is not a constant.
1060 * Instead, it is a slowly growing function of the number of
1061 * clean pages freed by the page daemon since the last
1062 * background laundering. Thus, as the ratio of dirty to
1063 * clean inactive pages grows, the amount of memory pressure
1064 * required to trigger laundering decreases. We ensure
1065 * that the threshold is non-zero after an inactive queue
1066 * scan, even if that scan failed to free a single clean page.
1067 */
1068trybackground:
1069 nclean = vmd->vmd_free_count +
1071 ndirty = vmd->vmd_pagequeues[PQ_LAUNDRY].pq_cnt;
1072 if (target == 0 && ndirty * isqrt(howmany(nfreed + 1,
1073 vmd->vmd_free_target - vmd->vmd_free_min)) >= nclean) {
1074 target = vmd->vmd_background_launder_target;
1075 }
1076
1077 /*
1078 * We have a non-zero background laundering target. If we've
1079 * laundered up to our maximum without observing a page daemon
1080 * request, just stop. This is a safety belt that ensures we
1081 * don't launder an excessive amount if memory pressure is low
1082 * and the ratio of dirty to clean pages is large. Otherwise,
1083 * proceed at the background laundering rate.
1084 */
1085 if (target > 0) {
1086 if (nfreed > 0) {
1087 nfreed = 0;
1088 last_target = target;
1089 } else if (last_target - target >=
1090 vm_background_launder_max * PAGE_SIZE / 1024) {
1091 target = 0;
1092 }
1093 launder = vm_background_launder_rate * PAGE_SIZE / 1024;
1094 launder /= VM_LAUNDER_RATE;
1095 if (launder > target)
1096 launder = target;
1097 }
1098
1099dolaundry:
1100 if (launder > 0) {
1101 /*
1102 * Because of I/O clustering, the number of laundered
1103 * pages could exceed "target" by the maximum size of
1104 * a cluster minus one.
1105 */
1106 target -= min(vm_pageout_launder(vmd, launder,
1107 in_shortfall), target);
1108 pause("laundp", hz / VM_LAUNDER_RATE);
1109 }
1110
1111 /*
1112 * If we're not currently laundering pages and the page daemon
1113 * hasn't posted a new request, sleep until the page daemon
1114 * kicks us.
1115 */
1117 if (target == 0 && vmd->vmd_laundry_request == VM_LAUNDRY_IDLE)
1118 (void)mtx_sleep(&vmd->vmd_laundry_request,
1119 vm_pagequeue_lockptr(pq), PVM, "launds", 0);
1120
1121 /*
1122 * If the pagedaemon has indicated that it's in shortfall, start
1123 * a shortfall laundering unless we're already in the middle of
1124 * one. This may preempt a background laundering.
1125 */
1127 (!in_shortfall || shortfall_cycle == 0)) {
1128 shortfall = vm_laundry_target(vmd) +
1130 target = 0;
1131 } else
1132 shortfall = 0;
1133
1134 if (target == 0)
1136 nfreed += vmd->vmd_clean_pages_freed;
1137 vmd->vmd_clean_pages_freed = 0;
1139 }
1140}
1141
1142/*
1143 * Compute the number of pages we want to try to move from the
1144 * active queue to either the inactive or laundry queue.
1145 *
1146 * When scanning active pages during a shortage, we make clean pages
1147 * count more heavily towards the page shortage than dirty pages.
1148 * This is because dirty pages must be laundered before they can be
1149 * reused and thus have less utility when attempting to quickly
1150 * alleviate a free page shortage. However, this weighting also
1151 * causes the scan to deactivate dirty pages more aggressively,
1152 * improving the effectiveness of clustering.
1153 */
1154static int
1156{
1157 int shortage;
1158
1159 shortage = vmd->vmd_inactive_target + vm_paging_target(vmd) -
1162 shortage *= act_scan_laundry_weight;
1163 return (shortage);
1164}
1165
1166/*
1167 * Scan the active queue. If there is no shortage of inactive pages, scan a
1168 * small portion of the queue in order to maintain quasi-LRU.
1169 */
1170static void
1171vm_pageout_scan_active(struct vm_domain *vmd, int page_shortage)
1172{
1173 struct scan_state ss;
1174 vm_object_t object;
1175 vm_page_t m, marker;
1176 struct vm_pagequeue *pq;
1177 vm_page_astate_t old, new;
1178 long min_scan;
1179 int act_delta, max_scan, ps_delta, refs, scan_tick;
1180 uint8_t nqueue;
1181
1182 marker = &vmd->vmd_markers[PQ_ACTIVE];
1183 pq = &vmd->vmd_pagequeues[PQ_ACTIVE];
1185
1186 /*
1187 * If we're just idle polling attempt to visit every
1188 * active page within 'update_period' seconds.
1189 */
1190 scan_tick = ticks;
1191 if (vm_pageout_update_period != 0) {
1192 min_scan = pq->pq_cnt;
1193 min_scan *= scan_tick - vmd->vmd_last_active_scan;
1194 min_scan /= hz * vm_pageout_update_period;
1195 } else
1196 min_scan = 0;
1197 if (min_scan > 0 || (page_shortage > 0 && pq->pq_cnt > 0))
1198 vmd->vmd_last_active_scan = scan_tick;
1199
1200 /*
1201 * Scan the active queue for pages that can be deactivated. Update
1202 * the per-page activity counter and use it to identify deactivation
1203 * candidates. Held pages may be deactivated.
1204 *
1205 * To avoid requeuing each page that remains in the active queue, we
1206 * implement the CLOCK algorithm. To keep the implementation of the
1207 * enqueue operation consistent for all page queues, we use two hands,
1208 * represented by marker pages. Scans begin at the first hand, which
1209 * precedes the second hand in the queue. When the two hands meet,
1210 * they are moved back to the head and tail of the queue, respectively,
1211 * and scanning resumes.
1212 */
1213 max_scan = page_shortage > 0 ? pq->pq_cnt : min_scan;
1214act_scan:
1215 vm_pageout_init_scan(&ss, pq, marker, &vmd->vmd_clock[0], max_scan);
1216 while ((m = vm_pageout_next(&ss, false)) != NULL) {
1217 if (__predict_false(m == &vmd->vmd_clock[1])) {
1219 TAILQ_REMOVE(&pq->pq_pl, &vmd->vmd_clock[0], plinks.q);
1220 TAILQ_REMOVE(&pq->pq_pl, &vmd->vmd_clock[1], plinks.q);
1221 TAILQ_INSERT_HEAD(&pq->pq_pl, &vmd->vmd_clock[0],
1222 plinks.q);
1223 TAILQ_INSERT_TAIL(&pq->pq_pl, &vmd->vmd_clock[1],
1224 plinks.q);
1225 max_scan -= ss.scanned;
1227 goto act_scan;
1228 }
1229 if (__predict_false((m->flags & PG_MARKER) != 0))
1230 continue;
1231
1232 /*
1233 * Don't touch a page that was removed from the queue after the
1234 * page queue lock was released. Otherwise, ensure that any
1235 * pending queue operations, such as dequeues for wired pages,
1236 * are handled.
1237 */
1238 if (vm_pageout_defer(m, PQ_ACTIVE, true))
1239 continue;
1240
1241 /*
1242 * A page's object pointer may be set to NULL before
1243 * the object lock is acquired.
1244 */
1245 object = atomic_load_ptr(&m->object);
1246 if (__predict_false(object == NULL))
1247 /*
1248 * The page has been removed from its object.
1249 */
1250 continue;
1251
1252 /* Deferred free of swap space. */
1253 if ((m->a.flags & PGA_SWAP_FREE) != 0 &&
1254 VM_OBJECT_TRYWLOCK(object)) {
1255 if (m->object == object)
1257 VM_OBJECT_WUNLOCK(object);
1258 }
1259
1260 /*
1261 * Check to see "how much" the page has been used.
1262 *
1263 * Test PGA_REFERENCED after calling pmap_ts_referenced() so
1264 * that a reference from a concurrently destroyed mapping is
1265 * observed here and now.
1266 *
1267 * Perform an unsynchronized object ref count check. While
1268 * the page lock ensures that the page is not reallocated to
1269 * another object, in particular, one with unmanaged mappings
1270 * that cannot support pmap_ts_referenced(), two races are,
1271 * nonetheless, possible:
1272 * 1) The count was transitioning to zero, but we saw a non-
1273 * zero value. pmap_ts_referenced() will return zero
1274 * because the page is not mapped.
1275 * 2) The count was transitioning to one, but we saw zero.
1276 * This race delays the detection of a new reference. At
1277 * worst, we will deactivate and reactivate the page.
1278 */
1279 refs = object->ref_count != 0 ? pmap_ts_referenced(m) : 0;
1280
1281 old = vm_page_astate_load(m);
1282 do {
1283 /*
1284 * Check to see if the page has been removed from the
1285 * queue since the first such check. Leave it alone if
1286 * so, discarding any references collected by
1287 * pmap_ts_referenced().
1288 */
1289 if (__predict_false(_vm_page_queue(old) == PQ_NONE)) {
1290 ps_delta = 0;
1291 break;
1292 }
1293
1294 /*
1295 * Advance or decay the act_count based on recent usage.
1296 */
1297 new = old;
1298 act_delta = refs;
1299 if ((old.flags & PGA_REFERENCED) != 0) {
1300 new.flags &= ~PGA_REFERENCED;
1301 act_delta++;
1302 }
1303 if (act_delta != 0) {
1304 new.act_count += ACT_ADVANCE + act_delta;
1305 if (new.act_count > ACT_MAX)
1306 new.act_count = ACT_MAX;
1307 } else {
1308 new.act_count -= min(new.act_count,
1309 ACT_DECLINE);
1310 }
1311
1312 if (new.act_count > 0) {
1313 /*
1314 * Adjust the activation count and keep the page
1315 * in the active queue. The count might be left
1316 * unchanged if it is saturated. The page may
1317 * have been moved to a different queue since we
1318 * started the scan, in which case we move it
1319 * back.
1320 */
1321 ps_delta = 0;
1322 if (old.queue != PQ_ACTIVE) {
1323 new.flags &= ~PGA_QUEUE_OP_MASK;
1324 new.flags |= PGA_REQUEUE;
1325 new.queue = PQ_ACTIVE;
1326 }
1327 } else {
1328 /*
1329 * When not short for inactive pages, let dirty
1330 * pages go through the inactive queue before
1331 * moving to the laundry queue. This gives them
1332 * some extra time to be reactivated,
1333 * potentially avoiding an expensive pageout.
1334 * However, during a page shortage, the inactive
1335 * queue is necessarily small, and so dirty
1336 * pages would only spend a trivial amount of
1337 * time in the inactive queue. Therefore, we
1338 * might as well place them directly in the
1339 * laundry queue to reduce queuing overhead.
1340 *
1341 * Calling vm_page_test_dirty() here would
1342 * require acquisition of the object's write
1343 * lock. However, during a page shortage,
1344 * directing dirty pages into the laundry queue
1345 * is only an optimization and not a
1346 * requirement. Therefore, we simply rely on
1347 * the opportunistic updates to the page's dirty
1348 * field by the pmap.
1349 */
1350 if (page_shortage <= 0) {
1351 nqueue = PQ_INACTIVE;
1352 ps_delta = 0;
1353 } else if (m->dirty == 0) {
1354 nqueue = PQ_INACTIVE;
1355 ps_delta = act_scan_laundry_weight;
1356 } else {
1357 nqueue = PQ_LAUNDRY;
1358 ps_delta = 1;
1359 }
1360
1361 new.flags &= ~PGA_QUEUE_OP_MASK;
1362 new.flags |= PGA_REQUEUE;
1363 new.queue = nqueue;
1364 }
1365 } while (!vm_page_pqstate_commit(m, &old, new));
1366
1367 page_shortage -= ps_delta;
1368 }
1370 TAILQ_REMOVE(&pq->pq_pl, &vmd->vmd_clock[0], plinks.q);
1371 TAILQ_INSERT_AFTER(&pq->pq_pl, marker, &vmd->vmd_clock[0], plinks.q);
1374}
1375
1376static int
1378 vm_page_t m)
1379{
1381
1383
1384 as = vm_page_astate_load(m);
1385 if (as.queue != PQ_INACTIVE || (as.flags & PGA_ENQUEUED) != 0)
1386 return (0);
1388 TAILQ_INSERT_BEFORE(marker, m, plinks.q);
1389 return (1);
1390}
1391
1392/*
1393 * Re-add stuck pages to the inactive queue. We will examine them again
1394 * during the next scan. If the queue state of a page has changed since
1395 * it was physically removed from the page queue in
1396 * vm_pageout_collect_batch(), don't do anything with that page.
1397 */
1398static void
1400 vm_page_t m)
1401{
1402 struct vm_pagequeue *pq;
1403 vm_page_t marker;
1404 int delta;
1405
1406 delta = 0;
1407 marker = ss->marker;
1408 pq = ss->pq;
1409
1410 if (m != NULL) {
1411 if (vm_batchqueue_insert(bq, m))
1412 return;
1414 delta += vm_pageout_reinsert_inactive_page(pq, marker, m);
1415 } else
1417 while ((m = vm_batchqueue_pop(bq)) != NULL)
1418 delta += vm_pageout_reinsert_inactive_page(pq, marker, m);
1419 vm_pagequeue_cnt_add(pq, delta);
1422}
1423
1424static void
1425vm_pageout_scan_inactive(struct vm_domain *vmd, int page_shortage)
1426{
1427 struct timeval start, end;
1428 struct scan_state ss;
1429 struct vm_batchqueue rq;
1430 struct vm_page marker_page;
1431 vm_page_t m, marker;
1432 struct vm_pagequeue *pq;
1433 vm_object_t object;
1434 vm_page_astate_t old, new;
1435 int act_delta, addl_page_shortage, starting_page_shortage, refs;
1436
1437 object = NULL;
1438 vm_batchqueue_init(&rq);
1439 getmicrouptime(&start);
1440
1441 /*
1442 * The addl_page_shortage is an estimate of the number of temporarily
1443 * stuck pages in the inactive queue. In other words, the
1444 * number of pages from the inactive count that should be
1445 * discounted in setting the target for the active queue scan.
1446 */
1447 addl_page_shortage = 0;
1448
1449 /*
1450 * Start scanning the inactive queue for pages that we can free. The
1451 * scan will stop when we reach the target or we have scanned the
1452 * entire queue. (Note that m->a.act_count is not used to make
1453 * decisions for the inactive queue, only for the active queue.)
1454 */
1455 starting_page_shortage = page_shortage;
1456 marker = &marker_page;
1457 vm_page_init_marker(marker, PQ_INACTIVE, 0);
1458 pq = &vmd->vmd_pagequeues[PQ_INACTIVE];
1460 vm_pageout_init_scan(&ss, pq, marker, NULL, pq->pq_cnt);
1461 while (page_shortage > 0 && (m = vm_pageout_next(&ss, true)) != NULL) {
1462 KASSERT((m->flags & PG_MARKER) == 0,
1463 ("marker page %p was dequeued", m));
1464
1465 /*
1466 * Don't touch a page that was removed from the queue after the
1467 * page queue lock was released. Otherwise, ensure that any
1468 * pending queue operations, such as dequeues for wired pages,
1469 * are handled.
1470 */
1471 if (vm_pageout_defer(m, PQ_INACTIVE, false))
1472 continue;
1473
1474 /*
1475 * Lock the page's object.
1476 */
1477 if (object == NULL || object != m->object) {
1478 if (object != NULL)
1479 VM_OBJECT_WUNLOCK(object);
1480 object = atomic_load_ptr(&m->object);
1481 if (__predict_false(object == NULL))
1482 /* The page is being freed by another thread. */
1483 continue;
1484
1485 /* Depends on type-stability. */
1486 VM_OBJECT_WLOCK(object);
1487 if (__predict_false(m->object != object)) {
1488 VM_OBJECT_WUNLOCK(object);
1489 object = NULL;
1490 goto reinsert;
1491 }
1492 }
1493
1494 if (vm_page_tryxbusy(m) == 0) {
1495 /*
1496 * Don't mess with busy pages. Leave them at
1497 * the front of the queue. Most likely, they
1498 * are being paged out and will leave the
1499 * queue shortly after the scan finishes. So,
1500 * they ought to be discounted from the
1501 * inactive count.
1502 */
1503 addl_page_shortage++;
1504 goto reinsert;
1505 }
1506
1507 /* Deferred free of swap space. */
1508 if ((m->a.flags & PGA_SWAP_FREE) != 0)
1510
1511 /*
1512 * Check for wirings now that we hold the object lock and have
1513 * exclusively busied the page. If the page is mapped, it may
1514 * still be wired by pmap lookups. The call to
1515 * vm_page_try_remove_all() below atomically checks for such
1516 * wirings and removes mappings. If the page is unmapped, the
1517 * wire count is guaranteed not to increase after this check.
1518 */
1519 if (__predict_false(vm_page_wired(m)))
1520 goto skip_page;
1521
1522 /*
1523 * Invalid pages can be easily freed. They cannot be
1524 * mapped, vm_page_free() asserts this.
1525 */
1526 if (vm_page_none_valid(m))
1527 goto free_page;
1528
1529 refs = object->ref_count != 0 ? pmap_ts_referenced(m) : 0;
1530
1531 for (old = vm_page_astate_load(m);;) {
1532 /*
1533 * Check to see if the page has been removed from the
1534 * queue since the first such check. Leave it alone if
1535 * so, discarding any references collected by
1536 * pmap_ts_referenced().
1537 */
1538 if (__predict_false(_vm_page_queue(old) == PQ_NONE))
1539 goto skip_page;
1540
1541 new = old;
1542 act_delta = refs;
1543 if ((old.flags & PGA_REFERENCED) != 0) {
1544 new.flags &= ~PGA_REFERENCED;
1545 act_delta++;
1546 }
1547 if (act_delta == 0) {
1548 ;
1549 } else if (object->ref_count != 0) {
1550 /*
1551 * Increase the activation count if the
1552 * page was referenced while in the
1553 * inactive queue. This makes it less
1554 * likely that the page will be returned
1555 * prematurely to the inactive queue.
1556 */
1557 new.act_count += ACT_ADVANCE +
1558 act_delta;
1559 if (new.act_count > ACT_MAX)
1560 new.act_count = ACT_MAX;
1561
1562 new.flags &= ~PGA_QUEUE_OP_MASK;
1563 new.flags |= PGA_REQUEUE;
1564 new.queue = PQ_ACTIVE;
1565 if (!vm_page_pqstate_commit(m, &old, new))
1566 continue;
1567
1568 VM_CNT_INC(v_reactivated);
1569 goto skip_page;
1570 } else if ((object->flags & OBJ_DEAD) == 0) {
1571 new.queue = PQ_INACTIVE;
1572 new.flags |= PGA_REQUEUE;
1573 if (!vm_page_pqstate_commit(m, &old, new))
1574 continue;
1575 goto skip_page;
1576 }
1577 break;
1578 }
1579
1580 /*
1581 * If the page appears to be clean at the machine-independent
1582 * layer, then remove all of its mappings from the pmap in
1583 * anticipation of freeing it. If, however, any of the page's
1584 * mappings allow write access, then the page may still be
1585 * modified until the last of those mappings are removed.
1586 */
1587 if (object->ref_count != 0) {
1589 if (m->dirty == 0 && !vm_page_try_remove_all(m))
1590 goto skip_page;
1591 }
1592
1593 /*
1594 * Clean pages can be freed, but dirty pages must be sent back
1595 * to the laundry, unless they belong to a dead object.
1596 * Requeueing dirty pages from dead objects is pointless, as
1597 * they are being paged out and freed by the thread that
1598 * destroyed the object.
1599 */
1600 if (m->dirty == 0) {
1601free_page:
1602 /*
1603 * Now we are guaranteed that no other threads are
1604 * manipulating the page, check for a last-second
1605 * reference that would save it from doom.
1606 */
1607 if (vm_pageout_defer(m, PQ_INACTIVE, false))
1608 goto skip_page;
1609
1610 /*
1611 * Because we dequeued the page and have already checked
1612 * for pending dequeue and enqueue requests, we can
1613 * safely disassociate the page from the inactive queue
1614 * without holding the queue lock.
1615 */
1616 m->a.queue = PQ_NONE;
1617 vm_page_free(m);
1618 page_shortage--;
1619 continue;
1620 }
1621 if ((object->flags & OBJ_DEAD) == 0)
1622 vm_page_launder(m);
1623skip_page:
1624 vm_page_xunbusy(m);
1625 continue;
1626reinsert:
1627 vm_pageout_reinsert_inactive(&ss, &rq, m);
1628 }
1629 if (object != NULL)
1630 VM_OBJECT_WUNLOCK(object);
1631 vm_pageout_reinsert_inactive(&ss, &rq, NULL);
1632 vm_pageout_reinsert_inactive(&ss, &ss.bq, NULL);
1636
1637 /*
1638 * Record the remaining shortage and the progress and rate it was made.
1639 */
1640 atomic_add_int(&vmd->vmd_addl_shortage, addl_page_shortage);
1641 getmicrouptime(&end);
1642 timevalsub(&end, &start);
1643 atomic_add_int(&vmd->vmd_inactive_us,
1644 end.tv_sec * 1000000 + end.tv_usec);
1645 atomic_add_int(&vmd->vmd_inactive_freed,
1646 starting_page_shortage - page_shortage);
1647}
1648
1649/*
1650 * Dispatch a number of inactive threads according to load and collect the
1651 * results to present a coherent view of paging activity on this domain.
1652 */
1653static int
1654vm_pageout_inactive_dispatch(struct vm_domain *vmd, int shortage)
1655{
1656 u_int freed, pps, slop, threads, us;
1657
1658 vmd->vmd_inactive_shortage = shortage;
1659 slop = 0;
1660
1661 /*
1662 * If we have more work than we can do in a quarter of our interval, we
1663 * fire off multiple threads to process it.
1664 */
1665 threads = vmd->vmd_inactive_threads;
1666 if (threads > 1 && vmd->vmd_inactive_pps != 0 &&
1667 shortage > vmd->vmd_inactive_pps / VM_INACT_SCAN_RATE / 4) {
1668 vmd->vmd_inactive_shortage /= threads;
1669 slop = shortage % threads;
1671 blockcount_acquire(&vmd->vmd_inactive_starting, threads - 1);
1672 blockcount_acquire(&vmd->vmd_inactive_running, threads - 1);
1673 wakeup(&vmd->vmd_inactive_shortage);
1675 }
1676
1677 /* Run the local thread scan. */
1679
1680 /*
1681 * Block until helper threads report results and then accumulate
1682 * totals.
1683 */
1684 blockcount_wait(&vmd->vmd_inactive_running, NULL, "vmpoid", PVM);
1685 freed = atomic_readandclear_int(&vmd->vmd_inactive_freed);
1686 VM_CNT_ADD(v_dfree, freed);
1687
1688 /*
1689 * Calculate the per-thread paging rate with an exponential decay of
1690 * prior results. Careful to avoid integer rounding errors with large
1691 * us values.
1692 */
1693 us = max(atomic_readandclear_int(&vmd->vmd_inactive_us), 1);
1694 if (us > 1000000)
1695 /* Keep rounding to tenths */
1696 pps = (freed * 10) / ((us * 10) / 1000000);
1697 else
1698 pps = (1000000 / us) * freed;
1699 vmd->vmd_inactive_pps = (vmd->vmd_inactive_pps / 2) + (pps / 2);
1700
1701 return (shortage - freed);
1702}
1703
1704/*
1705 * Attempt to reclaim the requested number of pages from the inactive queue.
1706 * Returns true if the shortage was addressed.
1707 */
1708static int
1709vm_pageout_inactive(struct vm_domain *vmd, int shortage, int *addl_shortage)
1710{
1711 struct vm_pagequeue *pq;
1712 u_int addl_page_shortage, deficit, page_shortage;
1713 u_int starting_page_shortage;
1714
1715 /*
1716 * vmd_pageout_deficit counts the number of pages requested in
1717 * allocations that failed because of a free page shortage. We assume
1718 * that the allocations will be reattempted and thus include the deficit
1719 * in our scan target.
1720 */
1721 deficit = atomic_readandclear_int(&vmd->vmd_pageout_deficit);
1722 starting_page_shortage = shortage + deficit;
1723
1724 /*
1725 * Run the inactive scan on as many threads as is necessary.
1726 */
1727 page_shortage = vm_pageout_inactive_dispatch(vmd, starting_page_shortage);
1728 addl_page_shortage = atomic_readandclear_int(&vmd->vmd_addl_shortage);
1729
1730 /*
1731 * Wake up the laundry thread so that it can perform any needed
1732 * laundering. If we didn't meet our target, we're in shortfall and
1733 * need to launder more aggressively. If PQ_LAUNDRY is empty and no
1734 * swap devices are configured, the laundry thread has no work to do, so
1735 * don't bother waking it up.
1736 *
1737 * The laundry thread uses the number of inactive queue scans elapsed
1738 * since the last laundering to determine whether to launder again, so
1739 * keep count.
1740 */
1741 if (starting_page_shortage > 0) {
1742 pq = &vmd->vmd_pagequeues[PQ_LAUNDRY];
1745 (pq->pq_cnt > 0 || atomic_load_acq_int(&swapdev_enabled))) {
1746 if (page_shortage > 0) {
1748 VM_CNT_INC(v_pdshortfalls);
1749 } else if (vmd->vmd_laundry_request !=
1751 vmd->vmd_laundry_request =
1753 wakeup(&vmd->vmd_laundry_request);
1754 }
1755 vmd->vmd_clean_pages_freed +=
1756 starting_page_shortage - page_shortage;
1758 }
1759
1760 /*
1761 * Wakeup the swapout daemon if we didn't free the targeted number of
1762 * pages.
1763 */
1764 if (page_shortage > 0)
1766
1767 /*
1768 * If the inactive queue scan fails repeatedly to meet its
1769 * target, kill the largest process.
1770 */
1771 vm_pageout_mightbe_oom(vmd, page_shortage, starting_page_shortage);
1772
1773 /*
1774 * Reclaim pages by swapping out idle processes, if configured to do so.
1775 */
1777
1778 /*
1779 * See the description of addl_page_shortage above.
1780 */
1781 *addl_shortage = addl_page_shortage + deficit;
1782
1783 return (page_shortage <= 0);
1784}
1785
1787
1788/*
1789 * The pagedaemon threads randlomly select one to perform the
1790 * OOM. Trying to kill processes before all pagedaemons
1791 * failed to reach free target is premature.
1792 */
1793static void
1794vm_pageout_mightbe_oom(struct vm_domain *vmd, int page_shortage,
1795 int starting_page_shortage)
1796{
1797 int old_vote;
1798
1799 if (starting_page_shortage <= 0 || starting_page_shortage !=
1800 page_shortage)
1801 vmd->vmd_oom_seq = 0;
1802 else
1803 vmd->vmd_oom_seq++;
1804 if (vmd->vmd_oom_seq < vm_pageout_oom_seq) {
1805 if (vmd->vmd_oom) {
1806 vmd->vmd_oom = FALSE;
1807 atomic_subtract_int(&vm_pageout_oom_vote, 1);
1808 }
1809 return;
1810 }
1811
1812 /*
1813 * Do not follow the call sequence until OOM condition is
1814 * cleared.
1815 */
1816 vmd->vmd_oom_seq = 0;
1817
1818 if (vmd->vmd_oom)
1819 return;
1820
1821 vmd->vmd_oom = TRUE;
1822 old_vote = atomic_fetchadd_int(&vm_pageout_oom_vote, 1);
1823 if (old_vote != vm_ndomains - 1)
1824 return;
1825
1826 /*
1827 * The current pagedaemon thread is the last in the quorum to
1828 * start OOM. Initiate the selection and signaling of the
1829 * victim.
1830 */
1832
1833 /*
1834 * After one round of OOM terror, recall our vote. On the
1835 * next pass, current pagedaemon would vote again if the low
1836 * memory condition is still there, due to vmd_oom being
1837 * false.
1838 */
1839 vmd->vmd_oom = FALSE;
1840 atomic_subtract_int(&vm_pageout_oom_vote, 1);
1841}
1842
1843/*
1844 * The OOM killer is the page daemon's action of last resort when
1845 * memory allocation requests have been stalled for a prolonged period
1846 * of time because it cannot reclaim memory. This function computes
1847 * the approximate number of physical pages that could be reclaimed if
1848 * the specified address space is destroyed.
1849 *
1850 * Private, anonymous memory owned by the address space is the
1851 * principal resource that we expect to recover after an OOM kill.
1852 * Since the physical pages mapped by the address space's COW entries
1853 * are typically shared pages, they are unlikely to be released and so
1854 * they are not counted.
1855 *
1856 * To get to the point where the page daemon runs the OOM killer, its
1857 * efforts to write-back vnode-backed pages may have stalled. This
1858 * could be caused by a memory allocation deadlock in the write path
1859 * that might be resolved by an OOM kill. Therefore, physical pages
1860 * belonging to vnode-backed objects are counted, because they might
1861 * be freed without being written out first if the address space holds
1862 * the last reference to an unlinked vnode.
1863 *
1864 * Similarly, physical pages belonging to OBJT_PHYS objects are
1865 * counted because the address space might hold the last reference to
1866 * the object.
1867 */
1868static long
1870{
1871 vm_map_t map;
1872 vm_map_entry_t entry;
1873 vm_object_t obj;
1874 long res;
1875
1876 map = &vmspace->vm_map;
1877 KASSERT(!map->system_map, ("system map"));
1878 sx_assert(&map->lock, SA_LOCKED);
1879 res = 0;
1880 VM_MAP_ENTRY_FOREACH(entry, map) {
1881 if ((entry->eflags & MAP_ENTRY_IS_SUB_MAP) != 0)
1882 continue;
1883 obj = entry->object.vm_object;
1884 if (obj == NULL)
1885 continue;
1886 if ((entry->eflags & MAP_ENTRY_NEEDS_COPY) != 0 &&
1887 obj->ref_count != 1)
1888 continue;
1889 if (obj->type == OBJT_DEFAULT || obj->type == OBJT_PHYS ||
1890 obj->type == OBJT_VNODE || (obj->flags & OBJ_SWAP) != 0)
1891 res += obj->resident_page_count;
1892 }
1893 return (res);
1894}
1895
1897static int vm_oom_pf_secs = 10;
1898SYSCTL_INT(_vm, OID_AUTO, oom_pf_secs, CTLFLAG_RWTUN, &vm_oom_pf_secs, 0,
1899 "");
1900static struct mtx vm_oom_ratelim_mtx;
1901
1902void
1903vm_pageout_oom(int shortage)
1904{
1905 const char *reason;
1906 struct proc *p, *bigproc;
1907 vm_offset_t size, bigsize;
1908 struct thread *td;
1909 struct vmspace *vm;
1910 int now;
1911 bool breakout;
1912
1913 /*
1914 * For OOM requests originating from vm_fault(), there is a high
1915 * chance that a single large process faults simultaneously in
1916 * several threads. Also, on an active system running many
1917 * processes of middle-size, like buildworld, all of them
1918 * could fault almost simultaneously as well.
1919 *
1920 * To avoid killing too many processes, rate-limit OOMs
1921 * initiated by vm_fault() time-outs on the waits for free
1922 * pages.
1923 */
1924 mtx_lock(&vm_oom_ratelim_mtx);
1925 now = ticks;
1926 if (shortage == VM_OOM_MEM_PF &&
1927 (u_int)(now - vm_oom_ratelim_last) < hz * vm_oom_pf_secs) {
1928 mtx_unlock(&vm_oom_ratelim_mtx);
1929 return;
1930 }
1931 vm_oom_ratelim_last = now;
1932 mtx_unlock(&vm_oom_ratelim_mtx);
1933
1934 /*
1935 * We keep the process bigproc locked once we find it to keep anyone
1936 * from messing with it; however, there is a possibility of
1937 * deadlock if process B is bigproc and one of its child processes
1938 * attempts to propagate a signal to B while we are waiting for A's
1939 * lock while walking this list. To avoid this, we don't block on
1940 * the process lock but just skip a process if it is already locked.
1941 */
1942 bigproc = NULL;
1943 bigsize = 0;
1944 sx_slock(&allproc_lock);
1945 FOREACH_PROC_IN_SYSTEM(p) {
1946 PROC_LOCK(p);
1947
1948 /*
1949 * If this is a system, protected or killed process, skip it.
1950 */
1951 if (p->p_state != PRS_NORMAL || (p->p_flag & (P_INEXEC |
1952 P_PROTECTED | P_SYSTEM | P_WEXIT)) != 0 ||
1953 p->p_pid == 1 || P_KILLED(p) ||
1954 (p->p_pid < 48 && swap_pager_avail != 0)) {
1955 PROC_UNLOCK(p);
1956 continue;
1957 }
1958 /*
1959 * If the process is in a non-running type state,
1960 * don't touch it. Check all the threads individually.
1961 */
1962 breakout = false;
1963 FOREACH_THREAD_IN_PROC(p, td) {
1964 thread_lock(td);
1965 if (!TD_ON_RUNQ(td) &&
1966 !TD_IS_RUNNING(td) &&
1967 !TD_IS_SLEEPING(td) &&
1968 !TD_IS_SUSPENDED(td) &&
1969 !TD_IS_SWAPPED(td)) {
1970 thread_unlock(td);
1971 breakout = true;
1972 break;
1973 }
1974 thread_unlock(td);
1975 }
1976 if (breakout) {
1977 PROC_UNLOCK(p);
1978 continue;
1979 }
1980 /*
1981 * get the process size
1982 */
1983 vm = vmspace_acquire_ref(p);
1984 if (vm == NULL) {
1985 PROC_UNLOCK(p);
1986 continue;
1987 }
1988 _PHOLD_LITE(p);
1989 PROC_UNLOCK(p);
1990 sx_sunlock(&allproc_lock);
1991 if (!vm_map_trylock_read(&vm->vm_map)) {
1992 vmspace_free(vm);
1993 sx_slock(&allproc_lock);
1994 PRELE(p);
1995 continue;
1996 }
1997 size = vmspace_swap_count(vm);
1998 if (shortage == VM_OOM_MEM || shortage == VM_OOM_MEM_PF)
1999 size += vm_pageout_oom_pagecount(vm);
2001 vmspace_free(vm);
2002 sx_slock(&allproc_lock);
2003
2004 /*
2005 * If this process is bigger than the biggest one,
2006 * remember it.
2007 */
2008 if (size > bigsize) {
2009 if (bigproc != NULL)
2010 PRELE(bigproc);
2011 bigproc = p;
2012 bigsize = size;
2013 } else {
2014 PRELE(p);
2015 }
2016 }
2017 sx_sunlock(&allproc_lock);
2018
2019 if (bigproc != NULL) {
2020 switch (shortage) {
2021 case VM_OOM_MEM:
2022 reason = "failed to reclaim memory";
2023 break;
2024 case VM_OOM_MEM_PF:
2025 reason = "a thread waited too long to allocate a page";
2026 break;
2027 case VM_OOM_SWAPZ:
2028 reason = "out of swap space";
2029 break;
2030 default:
2031 panic("unknown OOM reason %d", shortage);
2032 }
2033 if (vm_panic_on_oom != 0 && --vm_panic_on_oom == 0)
2034 panic("%s", reason);
2035 PROC_LOCK(bigproc);
2036 killproc(bigproc, reason);
2037 sched_nice(bigproc, PRIO_MIN);
2038 _PRELE(bigproc);
2039 PROC_UNLOCK(bigproc);
2040 }
2041}
2042
2043/*
2044 * Signal a free page shortage to subsystems that have registered an event
2045 * handler. Reclaim memory from UMA in the event of a severe shortage.
2046 * Return true if the free page count should be re-evaluated.
2047 */
2048static bool
2050{
2051 static int lowmem_ticks = 0;
2052 int last;
2053 bool ret;
2054
2055 ret = false;
2056
2057 last = atomic_load_int(&lowmem_ticks);
2058 while ((u_int)(ticks - last) / hz >= lowmem_period) {
2059 if (atomic_fcmpset_int(&lowmem_ticks, &last, ticks) == 0)
2060 continue;
2061
2062 /*
2063 * Decrease registered cache sizes.
2064 */
2065 SDT_PROBE0(vm, , , vm__lowmem_scan);
2066 EVENTHANDLER_INVOKE(vm_lowmem, VM_LOW_PAGES);
2067
2068 /*
2069 * We do this explicitly after the caches have been
2070 * drained above.
2071 */
2073 ret = true;
2074 break;
2075 }
2076
2077 /*
2078 * Kick off an asynchronous reclaim of cached memory if one of the
2079 * page daemons is failing to keep up with demand. Use the "severe"
2080 * threshold instead of "min" to ensure that we do not blow away the
2081 * caches if a subset of the NUMA domains are depleted by kernel memory
2082 * allocations; the domainset iterators automatically skip domains
2083 * below the "min" threshold on the first pass.
2084 *
2085 * UMA reclaim worker has its own rate-limiting mechanism, so don't
2086 * worry about kicking it too often.
2087 */
2088 if (vm_page_count_severe())
2090
2091 return (ret);
2092}
2093
2094static void
2096{
2097 struct vm_domain *vmd;
2098 u_int ofree;
2099 int addl_shortage, domain, shortage;
2100 bool target_met;
2101
2102 domain = (uintptr_t)arg;
2103 vmd = VM_DOMAIN(domain);
2104 shortage = 0;
2105 target_met = true;
2106
2107 /*
2108 * XXXKIB It could be useful to bind pageout daemon threads to
2109 * the cores belonging to the domain, from which vm_page_array
2110 * is allocated.
2111 */
2112
2113 KASSERT(vmd->vmd_segs != 0, ("domain without segments"));
2114 vmd->vmd_last_active_scan = ticks;
2115
2116 /*
2117 * The pageout daemon worker is never done, so loop forever.
2118 */
2119 while (TRUE) {
2121
2122 /*
2123 * We need to clear wanted before we check the limits. This
2124 * prevents races with wakers who will check wanted after they
2125 * reach the limit.
2126 */
2127 atomic_store_int(&vmd->vmd_pageout_wanted, 0);
2128
2129 /*
2130 * Might the page daemon need to run again?
2131 */
2132 if (vm_paging_needed(vmd, vmd->vmd_free_count)) {
2133 /*
2134 * Yes. If the scan failed to produce enough free
2135 * pages, sleep uninterruptibly for some time in the
2136 * hope that the laundry thread will clean some pages.
2137 */
2139 if (!target_met)
2140 pause("pwait", hz / VM_INACT_SCAN_RATE);
2141 } else {
2142 /*
2143 * No, sleep until the next wakeup or until pages
2144 * need to have their reference stats updated.
2145 */
2146 if (mtx_sleep(&vmd->vmd_pageout_wanted,
2147 vm_domain_pageout_lockptr(vmd), PDROP | PVM,
2148 "psleep", hz / VM_INACT_SCAN_RATE) == 0)
2149 VM_CNT_INC(v_pdwakeups);
2150 }
2151
2152 /* Prevent spurious wakeups by ensuring that wanted is set. */
2153 atomic_store_int(&vmd->vmd_pageout_wanted, 1);
2154
2155 /*
2156 * Use the controller to calculate how many pages to free in
2157 * this interval, and scan the inactive queue. If the lowmem
2158 * handlers appear to have freed up some pages, subtract the
2159 * difference from the inactive queue scan target.
2160 */
2161 shortage = pidctrl_daemon(&vmd->vmd_pid, vmd->vmd_free_count);
2162 if (shortage > 0) {
2163 ofree = vmd->vmd_free_count;
2164 if (vm_pageout_lowmem() && vmd->vmd_free_count > ofree)
2165 shortage -= min(vmd->vmd_free_count - ofree,
2166 (u_int)shortage);
2167 target_met = vm_pageout_inactive(vmd, shortage,
2168 &addl_shortage);
2169 } else
2170 addl_shortage = 0;
2171
2172 /*
2173 * Scan the active queue. A positive value for shortage
2174 * indicates that we must aggressively deactivate pages to avoid
2175 * a shortfall.
2176 */
2177 shortage = vm_pageout_active_target(vmd) + addl_shortage;
2178 vm_pageout_scan_active(vmd, shortage);
2179 }
2180}
2181
2182/*
2183 * vm_pageout_helper runs additional pageout daemons in times of high paging
2184 * activity.
2185 */
2186static void
2188{
2189 struct vm_domain *vmd;
2190 int domain;
2191
2192 domain = (uintptr_t)arg;
2193 vmd = VM_DOMAIN(domain);
2194
2196 for (;;) {
2197 msleep(&vmd->vmd_inactive_shortage,
2198 vm_domain_pageout_lockptr(vmd), PVM, "psleep", 0);
2199 blockcount_release(&vmd->vmd_inactive_starting, 1);
2200
2204
2205 /*
2206 * Release the running count while the pageout lock is held to
2207 * prevent wakeup races.
2208 */
2209 blockcount_release(&vmd->vmd_inactive_running, 1);
2210 }
2211}
2212
2213static int
2215{
2216 unsigned total_pageout_threads, eligible_cpus, domain_cpus;
2217
2218 if (VM_DOMAIN_EMPTY(vmd->vmd_domain))
2219 return (0);
2220
2221 /*
2222 * Semi-arbitrarily constrain pagedaemon threads to less than half the
2223 * total number of CPUs in the system as an upper limit.
2224 */
2227 else if (pageout_cpus_per_thread > mp_ncpus)
2228 pageout_cpus_per_thread = mp_ncpus;
2229
2230 total_pageout_threads = howmany(mp_ncpus, pageout_cpus_per_thread);
2231 domain_cpus = CPU_COUNT(&cpuset_domain[vmd->vmd_domain]);
2232
2233 /* Pagedaemons are not run in empty domains. */
2234 eligible_cpus = mp_ncpus;
2235 for (unsigned i = 0; i < vm_ndomains; i++)
2236 if (VM_DOMAIN_EMPTY(i))
2237 eligible_cpus -= CPU_COUNT(&cpuset_domain[i]);
2238
2239 /*
2240 * Assign a portion of the total pageout threads to this domain
2241 * corresponding to the fraction of pagedaemon-eligible CPUs in the
2242 * domain. In asymmetric NUMA systems, domains with more CPUs may be
2243 * allocated more threads than domains with fewer CPUs.
2244 */
2245 return (howmany(total_pageout_threads * domain_cpus, eligible_cpus));
2246}
2247
2248/*
2249 * Initialize basic pageout daemon settings. See the comment above the
2250 * definition of vm_domain for some explanation of how these thresholds are
2251 * used.
2252 */
2253static void
2255{
2256 struct vm_domain *vmd;
2257 struct sysctl_oid *oid;
2258
2259 vmd = VM_DOMAIN(domain);
2260 vmd->vmd_interrupt_free_min = 2;
2261
2262 /*
2263 * v_free_reserved needs to include enough for the largest
2264 * swap pager structures plus enough for any pv_entry structs
2265 * when paging.
2266 */
2267 vmd->vmd_pageout_free_min = 2 * MAXBSIZE / PAGE_SIZE +
2270 vmd->vmd_pageout_free_min + vmd->vmd_page_count / 768;
2271 vmd->vmd_free_min = vmd->vmd_page_count / 200;
2272 vmd->vmd_free_severe = vmd->vmd_free_min / 2;
2273 vmd->vmd_free_target = 4 * vmd->vmd_free_min + vmd->vmd_free_reserved;
2274 vmd->vmd_free_min += vmd->vmd_free_reserved;
2276 vmd->vmd_inactive_target = (3 * vmd->vmd_free_target) / 2;
2277 if (vmd->vmd_inactive_target > vmd->vmd_free_count / 3)
2278 vmd->vmd_inactive_target = vmd->vmd_free_count / 3;
2279
2280 /*
2281 * Set the default wakeup threshold to be 10% below the paging
2282 * target. This keeps the steady state out of shortfall.
2283 */
2284 vmd->vmd_pageout_wakeup_thresh = (vmd->vmd_free_target / 10) * 9;
2285
2286 /*
2287 * Target amount of memory to move out of the laundry queue during a
2288 * background laundering. This is proportional to the amount of system
2289 * memory.
2290 */
2292 vmd->vmd_free_min) / 10;
2293
2294 /* Initialize the pageout daemon pid controller. */
2295 pidctrl_init(&vmd->vmd_pid, hz / VM_INACT_SCAN_RATE,
2296 vmd->vmd_free_target, PIDCTRL_BOUND,
2297 PIDCTRL_KPD, PIDCTRL_KID, PIDCTRL_KDD);
2298 oid = SYSCTL_ADD_NODE(NULL, SYSCTL_CHILDREN(vmd->vmd_oid), OID_AUTO,
2299 "pidctrl", CTLFLAG_RD | CTLFLAG_MPSAFE, NULL, "");
2300 pidctrl_init_sysctl(&vmd->vmd_pid, SYSCTL_CHILDREN(oid));
2301
2303}
2304
2305static void
2307{
2308 u_long freecount;
2309 int i;
2310
2311 /*
2312 * Initialize some paging parameters.
2313 */
2314 if (vm_cnt.v_page_count < 2000)
2316
2317 freecount = 0;
2318 for (i = 0; i < vm_ndomains; i++) {
2319 struct vm_domain *vmd;
2320
2322 vmd = VM_DOMAIN(i);
2323 vm_cnt.v_free_reserved += vmd->vmd_free_reserved;
2324 vm_cnt.v_free_target += vmd->vmd_free_target;
2325 vm_cnt.v_free_min += vmd->vmd_free_min;
2326 vm_cnt.v_inactive_target += vmd->vmd_inactive_target;
2327 vm_cnt.v_pageout_free_min += vmd->vmd_pageout_free_min;
2328 vm_cnt.v_interrupt_free_min += vmd->vmd_interrupt_free_min;
2329 vm_cnt.v_free_severe += vmd->vmd_free_severe;
2330 freecount += vmd->vmd_free_count;
2331 }
2332
2333 /*
2334 * Set interval in seconds for active scan. We want to visit each
2335 * page at least once every ten minutes. This is to prevent worst
2336 * case paging behaviors with stale active LRU.
2337 */
2338 if (vm_pageout_update_period == 0)
2340
2341 /*
2342 * Set the maximum number of user-wired virtual pages. Historically the
2343 * main source of such pages was mlock(2) and mlockall(2). Hypervisors
2344 * may also request user-wired memory.
2345 */
2346 if (vm_page_max_user_wired == 0)
2347 vm_page_max_user_wired = 4 * freecount / 5;
2348}
2349
2350/*
2351 * vm_pageout is the high level pageout daemon.
2352 */
2353static void
2355{
2356 struct proc *p;
2357 struct thread *td;
2358 int error, first, i, j, pageout_threads;
2359
2360 p = curproc;
2361 td = curthread;
2362
2363 mtx_init(&vm_oom_ratelim_mtx, "vmoomr", NULL, MTX_DEF);
2365 for (first = -1, i = 0; i < vm_ndomains; i++) {
2366 if (VM_DOMAIN_EMPTY(i)) {
2367 if (bootverbose)
2368 printf("domain %d empty; skipping pageout\n",
2369 i);
2370 continue;
2371 }
2372 if (first == -1)
2373 first = i;
2374 else {
2375 error = kthread_add(vm_pageout_worker,
2376 (void *)(uintptr_t)i, p, NULL, 0, 0, "dom%d", i);
2377 if (error != 0)
2378 panic("starting pageout for domain %d: %d\n",
2379 i, error);
2380 }
2381 pageout_threads = VM_DOMAIN(i)->vmd_inactive_threads;
2382 for (j = 0; j < pageout_threads - 1; j++) {
2383 error = kthread_add(vm_pageout_helper,
2384 (void *)(uintptr_t)i, p, NULL, 0, 0,
2385 "dom%d helper%d", i, j);
2386 if (error != 0)
2387 panic("starting pageout helper %d for domain "
2388 "%d: %d\n", j, i, error);
2389 }
2390 error = kthread_add(vm_pageout_laundry_worker,
2391 (void *)(uintptr_t)i, p, NULL, 0, 0, "laundry: dom%d", i);
2392 if (error != 0)
2393 panic("starting laundry for domain %d: %d", i, error);
2394 }
2395 error = kthread_add(uma_reclaim_worker, NULL, p, NULL, 0, 0, "uma");
2396 if (error != 0)
2397 panic("starting uma_reclaim helper, error %d\n", error);
2398
2399 snprintf(td->td_name, sizeof(td->td_name), "dom%d", first);
2400 vm_pageout_worker((void *)(uintptr_t)first);
2401}
2402
2403/*
2404 * Perform an advisory wakeup of the page daemon.
2405 */
2406void
2408{
2409 struct vm_domain *vmd;
2410
2411 vmd = VM_DOMAIN(domain);
2413 if (curproc == pageproc)
2414 return;
2415
2416 if (atomic_fetchadd_int(&vmd->vmd_pageout_wanted, 1) == 0) {
2418 atomic_store_int(&vmd->vmd_pageout_wanted, 1);
2419 wakeup(&vmd->vmd_pageout_wanted);
2421 }
2422}
int pmap_ts_referenced(vm_page_t m)
struct vm_batchqueue bq
Definition: vm_pageout.c:215
vm_page_t marker
Definition: vm_pageout.c:217
struct vm_pagequeue * pq
Definition: vm_pageout.c:216
u_int vmd_free_min
Definition: vm_pagequeue.h:287
u_int vmd_page_count
Definition: vm_pagequeue.h:249
volatile u_int vmd_inactive_freed
Definition: vm_pagequeue.h:263
u_int vmd_inactive_target
Definition: vm_pagequeue.h:288
u_int vmd_domain
Definition: vm_pagequeue.h:248
blockcount_t vmd_inactive_starting
Definition: vm_pagequeue.h:261
u_int vmd_free_severe
Definition: vm_pagequeue.h:292
u_int vmd_clean_pages_freed
Definition: vm_pagequeue.h:283
struct vm_page vmd_clock[2]
Definition: vm_pagequeue.h:270
u_int vmd_free_reserved
Definition: vm_pagequeue.h:285
u_int vmd_inactive_threads
Definition: vm_pagequeue.h:258
struct vm_page vmd_markers[PQ_COUNT]
Definition: vm_pagequeue.h:268
u_int vmd_inactive_pps
Definition: vm_pagequeue.h:265
volatile u_int vmd_addl_shortage
Definition: vm_pagequeue.h:262
u_int vmd_pageout_free_min
Definition: vm_pagequeue.h:289
int vmd_pageout_wanted
Definition: vm_pagequeue.h:272
struct sysctl_oid * vmd_oid
Definition: vm_pagequeue.h:295
boolean_t vmd_oom
Definition: vm_pagequeue.h:257
u_int vmd_background_launder_target
Definition: vm_pagequeue.h:284
blockcount_t vmd_inactive_running
Definition: vm_pagequeue.h:260
volatile u_int vmd_inactive_us
Definition: vm_pagequeue.h:264
int vmd_last_active_scan
Definition: vm_pagequeue.h:267
struct pidctrl vmd_pid
Definition: vm_pagequeue.h:256
u_int vmd_inactive_shortage
Definition: vm_pagequeue.h:259
u_int vmd_free_target
Definition: vm_pagequeue.h:286
long vmd_segs
Definition: vm_pagequeue.h:250
u_int vmd_pageout_wakeup_thresh
Definition: vm_pagequeue.h:290
u_int vmd_pageout_deficit
Definition: vm_pagequeue.h:252
int vmd_oom_seq
Definition: vm_pagequeue.h:266
enum vm_domain::@14 vmd_laundry_request
u_int vmd_interrupt_free_min
Definition: vm_pagequeue.h:291
struct vm_pagequeue vmd_pagequeues[PQ_COUNT]
Definition: vm_pagequeue.h:238
Definition: vm_map.h:101
vm_eflags_t eflags
Definition: vm_map.h:110
union vm_map_object object
Definition: vm_map.h:108
Definition: vm_map.h:197
struct sx lock
Definition: vm_map.h:199
u_char system_map
Definition: vm_map.h:205
objtype_t type
Definition: vm_object.h:114
volatile u_int ref_count
Definition: vm_object.h:111
u_short flags
Definition: vm_object.h:115
int resident_page_count
Definition: vm_object.h:119
struct pglist pq_pl
Definition: vm_pagequeue.h:71
uint64_t pq_pdpages
Definition: vm_pagequeue.h:74
struct vm_map vm_map
Definition: vm_map.h:282
long vmspace_swap_count(struct vmspace *vmspace)
Definition: swap_pager.c:2754
int swap_pager_nswapdev(void)
Definition: swap_pager.c:1774
void swap_pager_swap_init(void)
Definition: swap_pager.c:596
int swap_pager_avail
void uma_reclaim(int req)
Definition: uma_core.c:5207
void uma_reclaim_worker(void *)
#define UMA_RECLAIM_TRIM
Definition: uma.h:431
void uma_reclaim_wakeup(void)
Definition: uma_core.c:5251
struct vm_object * vm_object
Definition: vm_map.h:91
uint16_t flags
Definition: vm_page.h:218
uint8_t queue
Definition: vm_page.h:219
@ OBJT_DEFAULT
Definition: vm.h:92
@ OBJT_VNODE
Definition: vm.h:94
@ OBJT_PHYS
Definition: vm.h:96
int vm_ndomains
Definition: vm_phys.c:81
void vmspace_free(struct vmspace *)
Definition: vm_map.c:390
struct vmspace * vmspace_acquire_ref(struct proc *)
Definition: vm_map.c:467
#define MAP_ENTRY_NEEDS_COPY
Definition: vm_map.h:123
#define vm_map_unlock_read(map)
Definition: vm_map.h:344
#define VM_MAP_ENTRY_FOREACH(it, map)
Definition: vm_map.h:505
#define MAP_ENTRY_IS_SUB_MAP
Definition: vm_map.h:121
#define vm_map_trylock_read(map)
Definition: vm_map.h:346
struct vmmeter __read_mostly vm_cnt
Definition: vm_meter.c:61
void vm_object_pip_add(vm_object_t object, short i)
Definition: vm_object.c:344
void vm_object_pip_wakeup(vm_object_t object)
Definition: vm_object.c:352
void vm_object_reference_locked(vm_object_t object)
Definition: vm_object.c:526
void vm_object_deallocate(vm_object_t object)
Definition: vm_object.c:625
#define VM_OBJECT_TRYWLOCK(object)
Definition: vm_object.h:266
#define VM_OBJECT_WLOCK(object)
Definition: vm_object.h:270
#define OBJ_SWAP
Definition: vm_object.h:205
#define OBJ_DEAD
Definition: vm_object.h:199
#define VM_OBJECT_WUNLOCK(object)
Definition: vm_object.h:274
#define VM_OBJECT_ASSERT_WLOCKED(object)
Definition: vm_object.h:252
void vm_page_activate(vm_page_t m)
Definition: vm_page.c:4159
void vm_page_init_marker(vm_page_t marker, int queue, uint16_t aflags)
Definition: vm_page.c:428
void vm_page_launder(vm_page_t m)
Definition: vm_page.c:4187
bool vm_page_pqstate_commit(vm_page_t m, vm_page_astate_t *old, vm_page_astate_t new)
Definition: vm_page.c:3573
void vm_page_unswappable(vm_page_t m)
Definition: vm_page.c:4197
vm_page_t vm_page_prev(vm_page_t m)
Definition: vm_page.c:1745
int vm_page_tryxbusy(vm_page_t m)
Definition: vm_page.c:1151
void vm_page_pqbatch_submit(vm_page_t m, uint8_t queue)
Definition: vm_page.c:3657
vm_page_t vm_page_next(vm_page_t m)
Definition: vm_page.c:1725
bool vm_page_try_remove_all(vm_page_t m)
Definition: vm_page.c:4348
void vm_page_sunbusy(vm_page_t m)
Definition: vm_page.c:972
void vm_page_busy_downgrade(vm_page_t m)
Definition: vm_page.c:909
void vm_page_test_dirty(vm_page_t m)
Definition: vm_page.c:5444
bool vm_page_try_remove_write(vm_page_t m)
Definition: vm_page.c:4358
void vm_page_free(vm_page_t m)
Definition: vm_page.c:1326
void vm_page_deactivate_noreuse(vm_page_t m)
Definition: vm_page.c:4177
static void vm_page_aflag_set(vm_page_t m, uint16_t bits)
Definition: vm_page.h:858
#define PQ_ACTIVE
Definition: vm_page.h:333
#define vm_page_assert_xbusied(m)
Definition: vm_page.h:745
static bool vm_page_in_laundry(vm_page_t m)
Definition: vm_page.h:945
#define PQ_NONE
Definition: vm_page.h:331
static bool vm_page_all_valid(vm_page_t m)
Definition: vm_page.h:990
static uint8_t _vm_page_queue(vm_page_astate_t as)
Definition: vm_page.h:910
#define VPO_UNMANAGED
Definition: vm_page.h:296
#define ACT_DECLINE
Definition: vm_page.h:468
#define PGA_REFERENCED
Definition: vm_page.h:438
#define ACT_ADVANCE
Definition: vm_page.h:469
#define PQ_INACTIVE
Definition: vm_page.h:332
static bool vm_page_none_valid(vm_page_t m)
Definition: vm_page.h:997
static __inline void vm_page_undirty(vm_page_t m)
Definition: vm_page.h:902
#define PGA_SWAP_FREE
Definition: vm_page.h:445
#define PG_MARKER
Definition: vm_page.h:462
#define PQ_LAUNDRY
Definition: vm_page.h:334
#define PQ_UNSWAPPABLE
Definition: vm_page.h:335
#define PGA_WRITEABLE
Definition: vm_page.h:437
static vm_page_astate_t vm_page_astate_load(vm_page_t m)
Definition: vm_page.h:811
#define ACT_MAX
Definition: vm_page.h:471
#define PGA_ENQUEUED
Definition: vm_page.h:440
static void vm_page_aflag_clear(vm_page_t m, uint16_t bits)
Definition: vm_page.h:840
#define vm_page_xunbusy(m)
Definition: vm_page.h:764
#define PGA_REQUEUE
Definition: vm_page.h:442
static bool vm_page_wired(vm_page_t m)
Definition: vm_page.h:983
#define PG_FICTITIOUS
Definition: vm_page.h:460
#define PGA_QUEUE_OP_MASK
Definition: vm_page.h:448
static void vm_pageout_scan_active(struct vm_domain *vmd, int page_shortage)
Definition: vm_pageout.c:1171
static int vm_pageout_active_target(struct vm_domain *vmd)
Definition: vm_pageout.c:1155
void pagedaemon_wakeup(int domain)
Definition: vm_pageout.c:2407
static int pageout_cpus_per_thread
Definition: vm_pageout.c:165
int vm_pageout_page_count
Definition: vm_pageout.c:152
static int vm_pageout_clean(vm_page_t m, int *numpagedout)
Definition: vm_pageout.c:604
static int disable_swap_pageouts
Definition: vm_pageout.c:174
static int vm_pageout_oom_vote
Definition: vm_pageout.c:1786
static void vm_pageout_swapon(void *arg __unused, struct swdevt *sp __unused)
Definition: vm_pageout.c:581
static int vm_panic_on_oom
Definition: vm_pageout.c:154
SYSCTL_ULONG(_vm, OID_AUTO, max_user_wired, CTLFLAG_RW, &vm_page_max_user_wired, 0, "system-wide limit to user-wired page count")
static int vm_pageout_inactive_dispatch(struct vm_domain *vmd, int shortage)
Definition: vm_pageout.c:1654
static int vm_pageout_reinsert_inactive_page(struct vm_pagequeue *pq, vm_page_t marker, vm_page_t m)
Definition: vm_pageout.c:1377
static int lowmem_period
Definition: vm_pageout.c:170
static int vm_pageout_oom_seq
Definition: vm_pageout.c:184
static __always_inline void vm_pageout_collect_batch(struct scan_state *ss, const bool dequeue)
Definition: vm_pageout.c:272
static int vm_oom_pf_secs
Definition: vm_pageout.c:1897
static void vm_pageout_helper(void *arg)
Definition: vm_pageout.c:2187
static int vm_pageout_update_period
Definition: vm_pageout.c:160
static void vm_pageout_mightbe_oom(struct vm_domain *vmd, int page_shortage, int starting_page_shortage)
Definition: vm_pageout.c:1794
static void vm_pageout(void)
Definition: vm_pageout.c:2354
static int pageout_lock_miss
Definition: vm_pageout.c:179
SDT_PROVIDER_DEFINE(vm)
static void vm_pageout_init(void)
Definition: vm_pageout.c:2306
static long vm_pageout_oom_pagecount(struct vmspace *vmspace)
Definition: vm_pageout.c:1869
void vm_pageout_oom(int shortage)
Definition: vm_pageout.c:1903
SYSCTL_INT(_vm, OID_AUTO, panic_on_oom, CTLFLAG_RWTUN, &vm_panic_on_oom, 0, "Panic on the given number of out-of-memory errors instead of " "killing the largest process")
SDT_PROBE_DEFINE(vm,,, vm__lowmem_scan)
static void vm_pageout_worker(void *arg)
Definition: vm_pageout.c:2095
SYSCTL_UINT(_vm, OID_AUTO, background_launder_rate, CTLFLAG_RWTUN, &vm_background_launder_rate, 0, "background laundering rate, in kilobytes per second")
static void vm_pageout_init_scan(struct scan_state *ss, struct vm_pagequeue *pq, vm_page_t marker, vm_page_t after, int maxscan)
Definition: vm_pageout.c:223
__FBSDID("$FreeBSD$")
static bool vm_pageout_lowmem(void)
Definition: vm_pageout.c:2049
static void vm_pageout_laundry_worker(void *arg)
Definition: vm_pageout.c:989
static u_int vm_background_launder_rate
Definition: vm_pageout.c:194
static u_int vm_background_launder_max
Definition: vm_pageout.c:199
static int act_scan_laundry_weight
Definition: vm_pageout.c:189
u_long vm_page_max_user_wired
Definition: vm_pageout.c:204
#define VM_INACT_SCAN_RATE
Definition: vm_pageout.c:149
static struct kproc_desc page_kp
Definition: vm_pageout.c:136
static __always_inline bool vm_pageout_defer(vm_page_t m, const uint8_t queue, const bool enqueued)
Definition: vm_pageout.c:331
static __always_inline vm_page_t vm_pageout_next(struct scan_state *ss, const bool dequeue)
Definition: vm_pageout.c:318
static struct mtx vm_oom_ratelim_mtx
Definition: vm_pageout.c:1900
static void vm_pageout_scan_inactive(struct vm_domain *vmd, int page_shortage)
Definition: vm_pageout.c:1425
static void vm_pageout_reinsert_inactive(struct scan_state *ss, struct vm_batchqueue *bq, vm_page_t m)
Definition: vm_pageout.c:1399
static void vm_pageout_end_scan(struct scan_state *ss)
Definition: vm_pageout.c:246
static int vm_pageout_launder(struct vm_domain *vmd, int launder, bool in_shortfall)
Definition: vm_pageout.c:721
static int get_pageout_threads_per_domain(const struct vm_domain *vmd)
Definition: vm_pageout.c:2214
SYSINIT(pagedaemon_init, SI_SUB_KTHREAD_PAGE, SI_ORDER_FIRST, vm_pageout_init, NULL)
#define VM_LAUNDER_RATE
Definition: vm_pageout.c:148
static int vm_pageout_inactive(struct vm_domain *vmd, int shortage, int *addl_shortage)
Definition: vm_pageout.c:1709
static int vm_oom_ratelim_last
Definition: vm_pageout.c:1896
static void vm_pageout_swapoff(void *arg __unused, struct swdevt *sp __unused)
Definition: vm_pageout.c:588
struct proc * pageproc
Definition: vm_pageout.c:134
static int vm_pageout_cluster(vm_page_t m)
Definition: vm_pageout.c:352
static void vm_pageout_init_domain(int domain)
Definition: vm_pageout.c:2254
int vm_pageout_flush(vm_page_t *mc, int count, int flags, int mreq, int *prunlen, boolean_t *eio)
Definition: vm_pageout.c:471
static u_int isqrt(u_int num)
Definition: vm_pageout.c:965
static int swapdev_enabled
Definition: vm_pageout.c:151
void vm_swapout_run(void)
Definition: vm_swapout.c:336
#define VM_OOM_SWAPZ
Definition: vm_pageout.h:83
void vm_swapout_run_idle(void)
Definition: vm_swapout.c:348
#define VM_OOM_MEM
Definition: vm_pageout.h:81
#define VM_LOW_PAGES
Definition: vm_pageout.h:89
#define VM_OOM_MEM_PF
Definition: vm_pageout.h:82
#define vm_domain_pageout_assert_unlocked(n)
Definition: vm_pagequeue.h:327
static int vm_paging_needed(struct vm_domain *vmd, u_int free_count)
Definition: vm_pagequeue.h:410
static bool vm_batchqueue_insert(struct vm_batchqueue *bq, vm_page_t m)
Definition: vm_pagequeue.h:360
#define vm_pagequeue_assert_locked(pq)
Definition: vm_pagequeue.h:304
#define vm_pagequeue_lockptr(pq)
Definition: vm_pagequeue.h:306
#define vm_pagequeue_unlock(pq)
Definition: vm_pagequeue.h:308
static int vm_laundry_target(struct vm_domain *vmd)
Definition: vm_pagequeue.h:441
static __inline void vm_pagequeue_cnt_add(struct vm_pagequeue *pq, int addend)
Definition: vm_pagequeue.h:335
static void vm_batchqueue_init(struct vm_batchqueue *bq)
Definition: vm_pagequeue.h:353
#define vm_pagequeue_lock(pq)
Definition: vm_pagequeue.h:305
#define vm_domain_pageout_lockptr(d)
Definition: vm_pagequeue.h:323
#define vm_domain_pageout_unlock(d)
Definition: vm_pagequeue.h:331
static vm_page_t vm_batchqueue_pop(struct vm_batchqueue *bq)
Definition: vm_pagequeue.h:371
@ VM_LAUNDRY_SHORTFALL
Definition: vm_pagequeue.h:41
@ VM_LAUNDRY_BACKGROUND
Definition: vm_pagequeue.h:40
@ VM_LAUNDRY_IDLE
Definition: vm_pagequeue.h:39
#define VM_DOMAIN(n)
Definition: vm_pagequeue.h:301
#define vm_domain_pageout_lock(d)
Definition: vm_pagequeue.h:329
#define VM_BATCHQUEUE_SIZE
Definition: vm_pagequeue.h:78
static int vm_paging_target(struct vm_domain *vmd)
Definition: vm_pagequeue.h:400
#define VM_DOMAIN_EMPTY(n)
Definition: vm_pagequeue.h:302
static __inline void vm_pager_put_pages(vm_object_t object, vm_page_t *m, int count, int flags, int *rtvals)
Definition: vm_pager.h:144
#define VM_PAGER_AGAIN
Definition: vm_pager.h:115
#define VM_PAGER_FAIL
Definition: vm_pager.h:112
static __inline void vm_pager_page_unswapped(vm_page_t m)
Definition: vm_pager.h:197
#define VM_PAGER_PEND
Definition: vm_pager.h:113
#define VM_PAGER_PUT_NOREUSE
Definition: vm_pager.h:119
#define VM_PAGER_ERROR
Definition: vm_pager.h:114
#define VM_PAGER_BAD
Definition: vm_pager.h:111
#define VM_PAGER_OK
Definition: vm_pager.h:110