kernel - Major signal path adjustments to fix races, tsleep race fixes, +more
[dragonfly.git] / sys / vm / vm_pageout.c
CommitLineData
984263bc 1/*
99ad9bc4
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2 * (MPSAFE)
3 *
984263bc
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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 *
11 * This code is derived from software contributed to Berkeley by
12 * The Mach Operating System project at Carnegie-Mellon University.
13 *
14 * Redistribution and use in source and binary forms, with or without
15 * modification, are permitted provided that the following conditions
16 * are met:
17 * 1. Redistributions of source code must retain the above copyright
18 * notice, this list of conditions and the following disclaimer.
19 * 2. Redistributions in binary form must reproduce the above copyright
20 * notice, this list of conditions and the following disclaimer in the
21 * documentation and/or other materials provided with the distribution.
984263bc
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22 * 4. Neither the name of the University nor the names of its contributors
23 * may be used to endorse or promote products derived from this software
24 * without specific prior written permission.
25 *
26 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
27 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
28 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
29 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
30 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
31 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
32 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
33 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
34 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
35 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
36 * SUCH DAMAGE.
37 *
38 * from: @(#)vm_pageout.c 7.4 (Berkeley) 5/7/91
39 *
40 *
41 * Copyright (c) 1987, 1990 Carnegie-Mellon University.
42 * All rights reserved.
43 *
44 * Authors: Avadis Tevanian, Jr., Michael Wayne Young
45 *
46 * Permission to use, copy, modify and distribute this software and
47 * its documentation is hereby granted, provided that both the copyright
48 * notice and this permission notice appear in all copies of the
49 * software, derivative works or modified versions, and any portions
50 * thereof, and that both notices appear in supporting documentation.
51 *
52 * CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS"
53 * CONDITION. CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND
54 * FOR ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
55 *
56 * Carnegie Mellon requests users of this software to return to
57 *
58 * Software Distribution Coordinator or Software.Distribution@CS.CMU.EDU
59 * School of Computer Science
60 * Carnegie Mellon University
61 * Pittsburgh PA 15213-3890
62 *
63 * any improvements or extensions that they make and grant Carnegie the
64 * rights to redistribute these changes.
65 *
66 * $FreeBSD: src/sys/vm/vm_pageout.c,v 1.151.2.15 2002/12/29 18:21:04 dillon Exp $
67 */
68
69/*
70 * The proverbial page-out daemon.
71 */
72
73#include "opt_vm.h"
74#include <sys/param.h>
75#include <sys/systm.h>
76#include <sys/kernel.h>
77#include <sys/proc.h>
78#include <sys/kthread.h>
79#include <sys/resourcevar.h>
80#include <sys/signalvar.h>
81#include <sys/vnode.h>
82#include <sys/vmmeter.h>
83#include <sys/sysctl.h>
84
85#include <vm/vm.h>
86#include <vm/vm_param.h>
87#include <sys/lock.h>
88#include <vm/vm_object.h>
89#include <vm/vm_page.h>
90#include <vm/vm_map.h>
91#include <vm/vm_pageout.h>
92#include <vm/vm_pager.h>
93#include <vm/swap_pager.h>
94#include <vm/vm_extern.h>
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95
96#include <sys/thread2.h>
b12defdc 97#include <sys/spinlock2.h>
12e4aaff 98#include <vm/vm_page2.h>
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99
100/*
101 * System initialization
102 */
103
104/* the kernel process "vm_pageout"*/
1388df65 105static int vm_pageout_clean (vm_page_t);
1388df65 106static int vm_pageout_free_page_calc (vm_size_t count);
bc6dffab 107struct thread *pagethread;
984263bc 108
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109#if !defined(NO_SWAPPING)
110/* the kernel process "vm_daemon"*/
1388df65 111static void vm_daemon (void);
bc6dffab 112static struct thread *vmthread;
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113
114static struct kproc_desc vm_kp = {
115 "vmdaemon",
116 vm_daemon,
bc6dffab 117 &vmthread
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118};
119SYSINIT(vmdaemon, SI_SUB_KTHREAD_VM, SI_ORDER_FIRST, kproc_start, &vm_kp)
120#endif
121
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122int vm_pages_needed=0; /* Event on which pageout daemon sleeps */
123int vm_pageout_deficit=0; /* Estimated number of pages deficit */
124int vm_pageout_pages_needed=0; /* flag saying that the pageout daemon needs pages */
125
126#if !defined(NO_SWAPPING)
127static int vm_pageout_req_swapout; /* XXX */
128static int vm_daemon_needed;
129#endif
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130static int vm_max_launder = 32;
131static int vm_pageout_stats_max=0, vm_pageout_stats_interval = 0;
132static int vm_pageout_full_stats_interval = 0;
133static int vm_pageout_stats_free_max=0, vm_pageout_algorithm=0;
134static int defer_swap_pageouts=0;
135static int disable_swap_pageouts=0;
136
137#if defined(NO_SWAPPING)
138static int vm_swap_enabled=0;
139static int vm_swap_idle_enabled=0;
140#else
141static int vm_swap_enabled=1;
142static int vm_swap_idle_enabled=0;
143#endif
144
145SYSCTL_INT(_vm, VM_PAGEOUT_ALGORITHM, pageout_algorithm,
146 CTLFLAG_RW, &vm_pageout_algorithm, 0, "LRU page mgmt");
147
148SYSCTL_INT(_vm, OID_AUTO, max_launder,
149 CTLFLAG_RW, &vm_max_launder, 0, "Limit dirty flushes in pageout");
150
151SYSCTL_INT(_vm, OID_AUTO, pageout_stats_max,
152 CTLFLAG_RW, &vm_pageout_stats_max, 0, "Max pageout stats scan length");
153
154SYSCTL_INT(_vm, OID_AUTO, pageout_full_stats_interval,
155 CTLFLAG_RW, &vm_pageout_full_stats_interval, 0, "Interval for full stats scan");
156
157SYSCTL_INT(_vm, OID_AUTO, pageout_stats_interval,
158 CTLFLAG_RW, &vm_pageout_stats_interval, 0, "Interval for partial stats scan");
159
160SYSCTL_INT(_vm, OID_AUTO, pageout_stats_free_max,
161 CTLFLAG_RW, &vm_pageout_stats_free_max, 0, "Not implemented");
162
163#if defined(NO_SWAPPING)
164SYSCTL_INT(_vm, VM_SWAPPING_ENABLED, swap_enabled,
165 CTLFLAG_RD, &vm_swap_enabled, 0, "");
166SYSCTL_INT(_vm, OID_AUTO, swap_idle_enabled,
167 CTLFLAG_RD, &vm_swap_idle_enabled, 0, "");
168#else
169SYSCTL_INT(_vm, VM_SWAPPING_ENABLED, swap_enabled,
170 CTLFLAG_RW, &vm_swap_enabled, 0, "Enable entire process swapout");
171SYSCTL_INT(_vm, OID_AUTO, swap_idle_enabled,
172 CTLFLAG_RW, &vm_swap_idle_enabled, 0, "Allow swapout on idle criteria");
173#endif
174
175SYSCTL_INT(_vm, OID_AUTO, defer_swapspace_pageouts,
176 CTLFLAG_RW, &defer_swap_pageouts, 0, "Give preference to dirty pages in mem");
177
178SYSCTL_INT(_vm, OID_AUTO, disable_swapspace_pageouts,
179 CTLFLAG_RW, &disable_swap_pageouts, 0, "Disallow swapout of dirty pages");
180
181static int pageout_lock_miss;
182SYSCTL_INT(_vm, OID_AUTO, pageout_lock_miss,
183 CTLFLAG_RD, &pageout_lock_miss, 0, "vget() lock misses during pageout");
184
185#define VM_PAGEOUT_PAGE_COUNT 16
186int vm_pageout_page_count = VM_PAGEOUT_PAGE_COUNT;
187
188int vm_page_max_wired; /* XXX max # of wired pages system-wide */
189
190#if !defined(NO_SWAPPING)
1388df65
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191typedef void freeer_fcn_t (vm_map_t, vm_object_t, vm_pindex_t, int);
192static void vm_pageout_map_deactivate_pages (vm_map_t, vm_pindex_t);
984263bc 193static freeer_fcn_t vm_pageout_object_deactivate_pages;
1388df65 194static void vm_req_vmdaemon (void);
984263bc 195#endif
027193eb 196static void vm_pageout_page_stats(int q);
984263bc 197
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198static __inline int
199PQAVERAGE(int n)
200{
201 if (n >= 0)
202 return((n + (PQ_L2_SIZE - 1)) / PQ_L2_SIZE + 1);
203 else
204 return((n - (PQ_L2_SIZE - 1)) / PQ_L2_SIZE - 1);
205}
206
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207/*
208 * vm_pageout_clean:
209 *
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210 * Clean the page and remove it from the laundry. The page must not be
211 * busy on-call.
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212 *
213 * We set the busy bit to cause potential page faults on this page to
214 * block. Note the careful timing, however, the busy bit isn't set till
215 * late and we cannot do anything that will mess with the page.
216 */
984263bc 217static int
57e43348 218vm_pageout_clean(vm_page_t m)
984263bc 219{
5f910b2f 220 vm_object_t object;
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221 vm_page_t mc[2*vm_pageout_page_count];
222 int pageout_count;
b12defdc 223 int error;
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224 int ib, is, page_base;
225 vm_pindex_t pindex = m->pindex;
226
227 object = m->object;
228
229 /*
230 * It doesn't cost us anything to pageout OBJT_DEFAULT or OBJT_SWAP
231 * with the new swapper, but we could have serious problems paging
232 * out other object types if there is insufficient memory.
233 *
234 * Unfortunately, checking free memory here is far too late, so the
235 * check has been moved up a procedural level.
236 */
237
238 /*
239 * Don't mess with the page if it's busy, held, or special
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240 *
241 * XXX do we really need to check hold_count here? hold_count
242 * isn't supposed to mess with vm_page ops except prevent the
243 * page from being reused.
984263bc 244 */
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245 if (m->hold_count != 0 || (m->flags & PG_UNMANAGED)) {
246 vm_page_wakeup(m);
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247 return 0;
248 }
249
250 mc[vm_pageout_page_count] = m;
251 pageout_count = 1;
252 page_base = vm_pageout_page_count;
253 ib = 1;
254 is = 1;
255
256 /*
257 * Scan object for clusterable pages.
258 *
259 * We can cluster ONLY if: ->> the page is NOT
260 * clean, wired, busy, held, or mapped into a
261 * buffer, and one of the following:
262 * 1) The page is inactive, or a seldom used
263 * active page.
264 * -or-
265 * 2) we force the issue.
266 *
267 * During heavy mmap/modification loads the pageout
268 * daemon can really fragment the underlying file
269 * due to flushing pages out of order and not trying
270 * align the clusters (which leave sporatic out-of-order
271 * holes). To solve this problem we do the reverse scan
272 * first and attempt to align our cluster, then do a
273 * forward scan if room remains.
274 */
275
398c240d 276 vm_object_hold(object);
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277more:
278 while (ib && pageout_count < vm_pageout_page_count) {
279 vm_page_t p;
280
281 if (ib > pindex) {
282 ib = 0;
283 break;
284 }
285
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286 p = vm_page_lookup_busy_try(object, pindex - ib, TRUE, &error);
287 if (error || p == NULL) {
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288 ib = 0;
289 break;
290 }
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291 if ((p->queue - p->pc) == PQ_CACHE ||
292 (p->flags & PG_UNMANAGED)) {
293 vm_page_wakeup(p);
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294 ib = 0;
295 break;
296 }
297 vm_page_test_dirty(p);
298 if ((p->dirty & p->valid) == 0 ||
027193eb 299 p->queue - p->pc != PQ_INACTIVE ||
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300 p->wire_count != 0 || /* may be held by buf cache */
301 p->hold_count != 0) { /* may be undergoing I/O */
b12defdc 302 vm_page_wakeup(p);
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303 ib = 0;
304 break;
305 }
306 mc[--page_base] = p;
307 ++pageout_count;
308 ++ib;
309 /*
310 * alignment boundry, stop here and switch directions. Do
311 * not clear ib.
312 */
313 if ((pindex - (ib - 1)) % vm_pageout_page_count == 0)
314 break;
315 }
316
317 while (pageout_count < vm_pageout_page_count &&
318 pindex + is < object->size) {
319 vm_page_t p;
320
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321 p = vm_page_lookup_busy_try(object, pindex + is, TRUE, &error);
322 if (error || p == NULL)
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323 break;
324 if (((p->queue - p->pc) == PQ_CACHE) ||
325 (p->flags & (PG_BUSY|PG_UNMANAGED)) || p->busy) {
b12defdc 326 vm_page_wakeup(p);
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327 break;
328 }
329 vm_page_test_dirty(p);
330 if ((p->dirty & p->valid) == 0 ||
027193eb 331 p->queue - p->pc != PQ_INACTIVE ||
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332 p->wire_count != 0 || /* may be held by buf cache */
333 p->hold_count != 0) { /* may be undergoing I/O */
b12defdc 334 vm_page_wakeup(p);
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335 break;
336 }
337 mc[page_base + pageout_count] = p;
338 ++pageout_count;
339 ++is;
340 }
341
342 /*
343 * If we exhausted our forward scan, continue with the reverse scan
344 * when possible, even past a page boundry. This catches boundry
345 * conditions.
346 */
347 if (ib && pageout_count < vm_pageout_page_count)
348 goto more;
349
398c240d
VS
350 vm_object_drop(object);
351
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352 /*
353 * we allow reads during pageouts...
354 */
355 return vm_pageout_flush(&mc[page_base], pageout_count, 0);
356}
357
358/*
359 * vm_pageout_flush() - launder the given pages
360 *
361 * The given pages are laundered. Note that we setup for the start of
362 * I/O ( i.e. busy the page ), mark it read-only, and bump the object
363 * reference count all in here rather then in the parent. If we want
364 * the parent to do more sophisticated things we may have to change
365 * the ordering.
99ad9bc4 366 *
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367 * The pages in the array must be busied by the caller and will be
368 * unbusied by this function.
984263bc 369 */
984263bc 370int
57e43348 371vm_pageout_flush(vm_page_t *mc, int count, int flags)
984263bc 372{
5f910b2f 373 vm_object_t object;
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374 int pageout_status[count];
375 int numpagedout = 0;
376 int i;
377
378 /*
17cde63e
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379 * Initiate I/O. Bump the vm_page_t->busy counter.
380 */
381 for (i = 0; i < count; i++) {
b12defdc
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382 KASSERT(mc[i]->valid == VM_PAGE_BITS_ALL,
383 ("vm_pageout_flush page %p index %d/%d: partially "
384 "invalid page", mc[i], i, count));
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385 vm_page_io_start(mc[i]);
386 }
387
388 /*
4530a3aa
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389 * We must make the pages read-only. This will also force the
390 * modified bit in the related pmaps to be cleared. The pager
391 * cannot clear the bit for us since the I/O completion code
392 * typically runs from an interrupt. The act of making the page
393 * read-only handles the case for us.
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MD
394 *
395 * Then we can unbusy the pages, we still hold a reference by virtue
396 * of our soft-busy.
984263bc 397 */
984263bc 398 for (i = 0; i < count; i++) {
984263bc 399 vm_page_protect(mc[i], VM_PROT_READ);
b12defdc 400 vm_page_wakeup(mc[i]);
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MD
401 }
402
403 object = mc[0]->object;
404 vm_object_pip_add(object, count);
405
406 vm_pager_put_pages(object, mc, count,
c439ad8f 407 (flags | ((object == &kernel_object) ? VM_PAGER_PUT_SYNC : 0)),
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408 pageout_status);
409
410 for (i = 0; i < count; i++) {
411 vm_page_t mt = mc[i];
412
413 switch (pageout_status[i]) {
414 case VM_PAGER_OK:
415 numpagedout++;
416 break;
417 case VM_PAGER_PEND:
418 numpagedout++;
419 break;
420 case VM_PAGER_BAD:
421 /*
422 * Page outside of range of object. Right now we
423 * essentially lose the changes by pretending it
424 * worked.
425 */
b12defdc 426 vm_page_busy_wait(mt, FALSE, "pgbad");
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427 pmap_clear_modify(mt);
428 vm_page_undirty(mt);
b12defdc 429 vm_page_wakeup(mt);
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430 break;
431 case VM_PAGER_ERROR:
432 case VM_PAGER_FAIL:
433 /*
c84c24da
MD
434 * A page typically cannot be paged out when we
435 * have run out of swap. We leave the page
436 * marked inactive and will try to page it out
437 * again later.
438 *
439 * Starvation of the active page list is used to
440 * determine when the system is massively memory
441 * starved.
984263bc 442 */
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MD
443 break;
444 case VM_PAGER_AGAIN:
445 break;
446 }
447
448 /*
449 * If the operation is still going, leave the page busy to
450 * block all other accesses. Also, leave the paging in
451 * progress indicator set so that we don't attempt an object
452 * collapse.
93afe6be
MD
453 *
454 * For any pages which have completed synchronously,
455 * deactivate the page if we are under a severe deficit.
456 * Do not try to enter them into the cache, though, they
457 * might still be read-heavy.
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458 */
459 if (pageout_status[i] != VM_PAGER_PEND) {
b12defdc 460 vm_page_busy_wait(mt, FALSE, "pgouw");
93afe6be
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461 if (vm_page_count_severe())
462 vm_page_deactivate(mt);
463#if 0
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464 if (!vm_page_count_severe() || !vm_page_try_to_cache(mt))
465 vm_page_protect(mt, VM_PROT_READ);
93afe6be 466#endif
a491077e 467 vm_page_io_finish(mt);
b12defdc 468 vm_page_wakeup(mt);
a491077e 469 vm_object_pip_wakeup(object);
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470 }
471 }
472 return numpagedout;
473}
474
475#if !defined(NO_SWAPPING)
476/*
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477 * deactivate enough pages to satisfy the inactive target
478 * requirements or if vm_page_proc_limit is set, then
479 * deactivate all of the pages in the object and its
480 * backing_objects.
984263bc 481 *
99ad9bc4 482 * The map must be locked.
398c240d 483 * The caller must hold the vm_object.
984263bc 484 */
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485static int vm_pageout_object_deactivate_pages_callback(vm_page_t, void *);
486
984263bc 487static void
57e43348 488vm_pageout_object_deactivate_pages(vm_map_t map, vm_object_t object,
99ad9bc4 489 vm_pindex_t desired, int map_remove_only)
984263bc 490{
1f804340 491 struct rb_vm_page_scan_info info;
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MD
492 vm_object_t lobject;
493 vm_object_t tobject;
984263bc 494 int remove_mode;
984263bc 495
05b9db80 496 ASSERT_LWKT_TOKEN_HELD(vm_object_token(object));
b12defdc 497 lobject = object;
398c240d 498
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MD
499 while (lobject) {
500 if (pmap_resident_count(vm_map_pmap(map)) <= desired)
501 break;
502 if (lobject->type == OBJT_DEVICE || lobject->type == OBJT_PHYS)
503 break;
504 if (lobject->paging_in_progress)
505 break;
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506
507 remove_mode = map_remove_only;
b12defdc 508 if (lobject->shadow_count > 1)
984263bc 509 remove_mode = 1;
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510
511 /*
a5fc46c9
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512 * scan the objects entire memory queue. We hold the
513 * object's token so the scan should not race anything.
06ecca5a 514 */
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515 info.limit = remove_mode;
516 info.map = map;
517 info.desired = desired;
b12defdc 518 vm_page_rb_tree_RB_SCAN(&lobject->rb_memq, NULL,
1f804340
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519 vm_pageout_object_deactivate_pages_callback,
520 &info
521 );
b12defdc
MD
522 while ((tobject = lobject->backing_object) != NULL) {
523 KKASSERT(tobject != object);
524 vm_object_hold(tobject);
525 if (tobject == lobject->backing_object)
526 break;
527 vm_object_drop(tobject);
528 }
05b9db80
MD
529 if (lobject != object) {
530 vm_object_lock_swap();
b12defdc 531 vm_object_drop(lobject);
05b9db80 532 }
b12defdc 533 lobject = tobject;
1f804340 534 }
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MD
535 if (lobject != object)
536 vm_object_drop(lobject);
1f804340 537}
99ad9bc4
MD
538
539/*
398c240d 540 * The caller must hold the vm_object.
99ad9bc4 541 */
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542static int
543vm_pageout_object_deactivate_pages_callback(vm_page_t p, void *data)
544{
545 struct rb_vm_page_scan_info *info = data;
546 int actcount;
984263bc 547
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MD
548 if (pmap_resident_count(vm_map_pmap(info->map)) <= info->desired) {
549 return(-1);
550 }
551 mycpu->gd_cnt.v_pdpages++;
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MD
552
553 if (vm_page_busy_try(p, TRUE))
554 return(0);
555 if (p->wire_count || p->hold_count || (p->flags & PG_UNMANAGED)) {
556 vm_page_wakeup(p);
557 return(0);
558 }
559 if (!pmap_page_exists_quick(vm_map_pmap(info->map), p)) {
560 vm_page_wakeup(p);
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561 return(0);
562 }
984263bc 563
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564 actcount = pmap_ts_referenced(p);
565 if (actcount) {
566 vm_page_flag_set(p, PG_REFERENCED);
567 } else if (p->flags & PG_REFERENCED) {
568 actcount = 1;
569 }
570
b12defdc 571 vm_page_and_queue_spin_lock(p);
027193eb 572 if (p->queue - p->pc != PQ_ACTIVE && (p->flags & PG_REFERENCED)) {
b12defdc 573 vm_page_and_queue_spin_unlock(p);
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574 vm_page_activate(p);
575 p->act_count += actcount;
576 vm_page_flag_clear(p, PG_REFERENCED);
027193eb 577 } else if (p->queue - p->pc == PQ_ACTIVE) {
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578 if ((p->flags & PG_REFERENCED) == 0) {
579 p->act_count -= min(p->act_count, ACT_DECLINE);
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580 if (!info->limit &&
581 (vm_pageout_algorithm || (p->act_count == 0))) {
582 vm_page_and_queue_spin_unlock(p);
984263bc 583 vm_page_protect(p, VM_PROT_NONE);
1f804340
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584 vm_page_deactivate(p);
585 } else {
027193eb
MD
586 TAILQ_REMOVE(&vm_page_queues[p->queue].pl,
587 p, pageq);
588 TAILQ_INSERT_TAIL(&vm_page_queues[p->queue].pl,
589 p, pageq);
b12defdc 590 vm_page_and_queue_spin_unlock(p);
984263bc 591 }
1f804340 592 } else {
b12defdc 593 vm_page_and_queue_spin_unlock(p);
1f804340
MD
594 vm_page_activate(p);
595 vm_page_flag_clear(p, PG_REFERENCED);
b12defdc
MD
596
597 vm_page_and_queue_spin_lock(p);
027193eb 598 if (p->queue - p->pc == PQ_ACTIVE) {
b12defdc
MD
599 if (p->act_count < (ACT_MAX - ACT_ADVANCE))
600 p->act_count += ACT_ADVANCE;
027193eb
MD
601 TAILQ_REMOVE(&vm_page_queues[p->queue].pl,
602 p, pageq);
603 TAILQ_INSERT_TAIL(&vm_page_queues[p->queue].pl,
604 p, pageq);
b12defdc
MD
605 }
606 vm_page_and_queue_spin_unlock(p);
984263bc 607 }
027193eb 608 } else if (p->queue - p->pc == PQ_INACTIVE) {
b12defdc 609 vm_page_and_queue_spin_unlock(p);
1f804340 610 vm_page_protect(p, VM_PROT_NONE);
b12defdc
MD
611 } else {
612 vm_page_and_queue_spin_unlock(p);
984263bc 613 }
b12defdc 614 vm_page_wakeup(p);
1f804340 615 return(0);
984263bc
MD
616}
617
618/*
99ad9bc4 619 * Deactivate some number of pages in a map, try to do it fairly, but
984263bc
MD
620 * that is really hard to do.
621 */
622static void
57e43348 623vm_pageout_map_deactivate_pages(vm_map_t map, vm_pindex_t desired)
984263bc
MD
624{
625 vm_map_entry_t tmpe;
626 vm_object_t obj, bigobj;
627 int nothingwired;
628
df4f70a6 629 if (lockmgr(&map->lock, LK_EXCLUSIVE | LK_NOWAIT)) {
984263bc
MD
630 return;
631 }
632
633 bigobj = NULL;
634 nothingwired = TRUE;
635
636 /*
637 * first, search out the biggest object, and try to free pages from
638 * that.
639 */
640 tmpe = map->header.next;
641 while (tmpe != &map->header) {
1b874851
MD
642 switch(tmpe->maptype) {
643 case VM_MAPTYPE_NORMAL:
644 case VM_MAPTYPE_VPAGETABLE:
984263bc
MD
645 obj = tmpe->object.vm_object;
646 if ((obj != NULL) && (obj->shadow_count <= 1) &&
647 ((bigobj == NULL) ||
648 (bigobj->resident_page_count < obj->resident_page_count))) {
649 bigobj = obj;
650 }
1b874851
MD
651 break;
652 default:
653 break;
984263bc
MD
654 }
655 if (tmpe->wired_count > 0)
656 nothingwired = FALSE;
657 tmpe = tmpe->next;
658 }
659
05b9db80
MD
660 if (bigobj) {
661 vm_object_hold(bigobj);
984263bc 662 vm_pageout_object_deactivate_pages(map, bigobj, desired, 0);
05b9db80
MD
663 vm_object_drop(bigobj);
664 }
984263bc
MD
665
666 /*
667 * Next, hunt around for other pages to deactivate. We actually
668 * do this search sort of wrong -- .text first is not the best idea.
669 */
670 tmpe = map->header.next;
671 while (tmpe != &map->header) {
672 if (pmap_resident_count(vm_map_pmap(map)) <= desired)
673 break;
1b874851
MD
674 switch(tmpe->maptype) {
675 case VM_MAPTYPE_NORMAL:
676 case VM_MAPTYPE_VPAGETABLE:
984263bc 677 obj = tmpe->object.vm_object;
05b9db80
MD
678 if (obj) {
679 vm_object_hold(obj);
984263bc 680 vm_pageout_object_deactivate_pages(map, obj, desired, 0);
05b9db80
MD
681 vm_object_drop(obj);
682 }
1b874851
MD
683 break;
684 default:
685 break;
984263bc
MD
686 }
687 tmpe = tmpe->next;
688 };
689
690 /*
691 * Remove all mappings if a process is swapped out, this will free page
692 * table pages.
693 */
694 if (desired == 0 && nothingwired)
695 pmap_remove(vm_map_pmap(map),
88181b08 696 VM_MIN_USER_ADDRESS, VM_MAX_USER_ADDRESS);
984263bc 697 vm_map_unlock(map);
984263bc
MD
698}
699#endif
700
701/*
a5fc46c9
MD
702 * Called when the pageout scan wants to free a page. We no longer
703 * try to cycle the vm_object here with a reference & dealloc, which can
704 * cause a non-trivial object collapse in a critical path.
99ad9bc4 705 *
a5fc46c9
MD
706 * It is unclear why we cycled the ref_count in the past, perhaps to try
707 * to optimize shadow chain collapses but I don't quite see why it would
708 * be necessary. An OBJ_DEAD object should terminate any and all vm_pages
709 * synchronously and not have to be kicked-start.
984263bc 710 */
99ad9bc4 711static void
95813af0
MD
712vm_pageout_page_free(vm_page_t m)
713{
984263bc
MD
714 vm_page_protect(m, VM_PROT_NONE);
715 vm_page_free(m);
984263bc
MD
716}
717
718/*
20479584 719 * vm_pageout_scan does the dirty work for the pageout daemon.
984263bc 720 */
8fa76237
MD
721struct vm_pageout_scan_info {
722 struct proc *bigproc;
723 vm_offset_t bigsize;
724};
725
726static int vm_pageout_scan_callback(struct proc *p, void *data);
727
20479584 728static int
51c99c61 729vm_pageout_scan_inactive(int pass, int q, int avail_shortage,
027193eb 730 int *vnodes_skippedp)
984263bc 731{
b12defdc 732 vm_page_t m;
984263bc 733 struct vm_page marker;
5d6a945b 734 struct vnode *vpfailed; /* warning, allowed to be stale */
027193eb
MD
735 int maxscan;
736 int delta = 0;
984263bc
MD
737 vm_object_t object;
738 int actcount;
984263bc 739 int maxlaunder;
984263bc
MD
740
741 /*
984263bc
MD
742 * Start scanning the inactive queue for pages we can move to the
743 * cache or free. The scan will stop when the target is reached or
744 * we have scanned the entire inactive queue. Note that m->act_count
745 * is not used to form decisions for the inactive queue, only for the
746 * active queue.
747 *
748 * maxlaunder limits the number of dirty pages we flush per scan.
749 * For most systems a smaller value (16 or 32) is more robust under
750 * extreme memory and disk pressure because any unnecessary writes
751 * to disk can result in extreme performance degredation. However,
752 * systems with excessive dirty pages (especially when MAP_NOSYNC is
753 * used) will die horribly with limited laundering. If the pageout
754 * daemon cannot clean enough pages in the first pass, we let it go
755 * all out in succeeding passes.
756 */
757 if ((maxlaunder = vm_max_launder) <= 1)
758 maxlaunder = 1;
759 if (pass)
760 maxlaunder = 10000;
761
06ecca5a 762 /*
b12defdc
MD
763 * Initialize our marker
764 */
765 bzero(&marker, sizeof(marker));
766 marker.flags = PG_BUSY | PG_FICTITIOUS | PG_MARKER;
027193eb
MD
767 marker.queue = PQ_INACTIVE + q;
768 marker.pc = q;
b12defdc
MD
769 marker.wire_count = 1;
770
771 /*
772 * Inactive queue scan.
773 *
774 * NOTE: The vm_page must be spinlocked before the queue to avoid
775 * deadlocks, so it is easiest to simply iterate the loop
776 * with the queue unlocked at the top.
06ecca5a 777 */
5d6a945b 778 vpfailed = NULL;
b12defdc 779
027193eb
MD
780 vm_page_queues_spin_lock(PQ_INACTIVE + q);
781 TAILQ_INSERT_HEAD(&vm_page_queues[PQ_INACTIVE + q].pl, &marker, pageq);
51c99c61 782 maxscan = vm_page_queues[PQ_INACTIVE + q].lcnt;
027193eb 783 vm_page_queues_spin_unlock(PQ_INACTIVE + q);
b12defdc
MD
784
785 while ((m = TAILQ_NEXT(&marker, pageq)) != NULL &&
51c99c61 786 maxscan-- > 0 && avail_shortage - delta > 0)
b12defdc
MD
787 {
788 vm_page_and_queue_spin_lock(m);
789 if (m != TAILQ_NEXT(&marker, pageq)) {
790 vm_page_and_queue_spin_unlock(m);
791 ++maxscan;
792 continue;
793 }
027193eb
MD
794 KKASSERT(m->queue - m->pc == PQ_INACTIVE);
795 TAILQ_REMOVE(&vm_page_queues[PQ_INACTIVE + q].pl,
b12defdc 796 &marker, pageq);
027193eb 797 TAILQ_INSERT_AFTER(&vm_page_queues[PQ_INACTIVE + q].pl, m,
b12defdc 798 &marker, pageq);
12e4aaff 799 mycpu->gd_cnt.v_pdpages++;
984263bc 800
06ecca5a 801 /*
b12defdc 802 * Skip marker pages
06ecca5a 803 */
b12defdc
MD
804 if (m->flags & PG_MARKER) {
805 vm_page_and_queue_spin_unlock(m);
806 continue;
807 }
984263bc
MD
808
809 /*
b12defdc
MD
810 * Try to busy the page. Don't mess with pages which are
811 * already busy or reorder them in the queue.
984263bc 812 */
b12defdc
MD
813 if (vm_page_busy_try(m, TRUE)) {
814 vm_page_and_queue_spin_unlock(m);
984263bc 815 continue;
b12defdc
MD
816 }
817 vm_page_and_queue_spin_unlock(m);
027193eb 818 KKASSERT(m->queue - m->pc == PQ_INACTIVE);
984263bc 819
d2d8515b
MD
820 lwkt_yield();
821
984263bc 822 /*
b12defdc
MD
823 * The page has been successfully busied and is now no
824 * longer spinlocked. The queue is no longer spinlocked
825 * either.
984263bc 826 */
06ecca5a 827
984263bc 828 /*
90244566
MD
829 * It is possible for a page to be busied ad-hoc (e.g. the
830 * pmap_collect() code) and wired and race against the
831 * allocation of a new page. vm_page_alloc() may be forced
832 * to deactivate the wired page in which case it winds up
833 * on the inactive queue and must be handled here. We
834 * correct the problem simply by unqueuing the page.
835 */
836 if (m->wire_count) {
837 vm_page_unqueue_nowakeup(m);
838 vm_page_wakeup(m);
839 kprintf("WARNING: pagedaemon: wired page on "
840 "inactive queue %p\n", m);
841 continue;
842 }
843
844 /*
b12defdc 845 * A held page may be undergoing I/O, so skip it.
984263bc 846 */
b12defdc
MD
847 if (m->hold_count) {
848 vm_page_and_queue_spin_lock(m);
027193eb
MD
849 if (m->queue - m->pc == PQ_INACTIVE) {
850 TAILQ_REMOVE(
851 &vm_page_queues[PQ_INACTIVE + q].pl,
852 m, pageq);
853 TAILQ_INSERT_TAIL(
854 &vm_page_queues[PQ_INACTIVE + q].pl,
855 m, pageq);
b12defdc
MD
856 }
857 vm_page_and_queue_spin_unlock(m);
858 ++vm_swapcache_inactive_heuristic;
859 vm_page_wakeup(m);
984263bc
MD
860 continue;
861 }
862
984263bc 863 if (m->object->ref_count == 0) {
06ecca5a
MD
864 /*
865 * If the object is not being used, we ignore previous
866 * references.
867 */
984263bc
MD
868 vm_page_flag_clear(m, PG_REFERENCED);
869 pmap_clear_reference(m);
b12defdc 870 /* fall through to end */
984263bc 871 } else if (((m->flags & PG_REFERENCED) == 0) &&
06ecca5a
MD
872 (actcount = pmap_ts_referenced(m))) {
873 /*
874 * Otherwise, if the page has been referenced while
875 * in the inactive queue, we bump the "activation
876 * count" upwards, making it less likely that the
877 * page will be added back to the inactive queue
878 * prematurely again. Here we check the page tables
879 * (or emulated bits, if any), given the upper level
880 * VM system not knowing anything about existing
881 * references.
882 */
984263bc
MD
883 vm_page_activate(m);
884 m->act_count += (actcount + ACT_ADVANCE);
b12defdc 885 vm_page_wakeup(m);
984263bc
MD
886 continue;
887 }
888
889 /*
b12defdc
MD
890 * (m) is still busied.
891 *
984263bc
MD
892 * If the upper level VM system knows about any page
893 * references, we activate the page. We also set the
894 * "activation count" higher than normal so that we will less
895 * likely place pages back onto the inactive queue again.
896 */
897 if ((m->flags & PG_REFERENCED) != 0) {
898 vm_page_flag_clear(m, PG_REFERENCED);
899 actcount = pmap_ts_referenced(m);
900 vm_page_activate(m);
901 m->act_count += (actcount + ACT_ADVANCE + 1);
b12defdc 902 vm_page_wakeup(m);
984263bc
MD
903 continue;
904 }
905
906 /*
907 * If the upper level VM system doesn't know anything about
908 * the page being dirty, we have to check for it again. As
909 * far as the VM code knows, any partially dirty pages are
910 * fully dirty.
41a01a4d
MD
911 *
912 * Pages marked PG_WRITEABLE may be mapped into the user
913 * address space of a process running on another cpu. A
914 * user process (without holding the MP lock) running on
915 * another cpu may be able to touch the page while we are
17cde63e
MD
916 * trying to remove it. vm_page_cache() will handle this
917 * case for us.
984263bc
MD
918 */
919 if (m->dirty == 0) {
920 vm_page_test_dirty(m);
921 } else {
922 vm_page_dirty(m);
923 }
924
984263bc 925 if (m->valid == 0) {
41a01a4d
MD
926 /*
927 * Invalid pages can be easily freed
928 */
984263bc 929 vm_pageout_page_free(m);
12e4aaff 930 mycpu->gd_cnt.v_dfree++;
027193eb 931 ++delta;
984263bc
MD
932 } else if (m->dirty == 0) {
933 /*
41a01a4d
MD
934 * Clean pages can be placed onto the cache queue.
935 * This effectively frees them.
984263bc
MD
936 */
937 vm_page_cache(m);
027193eb 938 ++delta;
984263bc
MD
939 } else if ((m->flags & PG_WINATCFLS) == 0 && pass == 0) {
940 /*
941 * Dirty pages need to be paged out, but flushing
942 * a page is extremely expensive verses freeing
943 * a clean page. Rather then artificially limiting
944 * the number of pages we can flush, we instead give
945 * dirty pages extra priority on the inactive queue
946 * by forcing them to be cycled through the queue
947 * twice before being flushed, after which the
948 * (now clean) page will cycle through once more
949 * before being freed. This significantly extends
950 * the thrash point for a heavily loaded machine.
951 */
984263bc 952 vm_page_flag_set(m, PG_WINATCFLS);
b12defdc 953 vm_page_and_queue_spin_lock(m);
027193eb
MD
954 if (m->queue - m->pc == PQ_INACTIVE) {
955 TAILQ_REMOVE(
956 &vm_page_queues[PQ_INACTIVE + q].pl,
957 m, pageq);
958 TAILQ_INSERT_TAIL(
959 &vm_page_queues[PQ_INACTIVE + q].pl,
960 m, pageq);
b12defdc
MD
961 }
962 vm_page_and_queue_spin_unlock(m);
e527fb6b 963 ++vm_swapcache_inactive_heuristic;
b12defdc 964 vm_page_wakeup(m);
984263bc
MD
965 } else if (maxlaunder > 0) {
966 /*
967 * We always want to try to flush some dirty pages if
968 * we encounter them, to keep the system stable.
969 * Normally this number is small, but under extreme
970 * pressure where there are insufficient clean pages
971 * on the inactive queue, we may have to go all out.
972 */
973 int swap_pageouts_ok;
974 struct vnode *vp = NULL;
975
976 object = m->object;
977
978 if ((object->type != OBJT_SWAP) && (object->type != OBJT_DEFAULT)) {
979 swap_pageouts_ok = 1;
980 } else {
981 swap_pageouts_ok = !(defer_swap_pageouts || disable_swap_pageouts);
982 swap_pageouts_ok |= (!disable_swap_pageouts && defer_swap_pageouts &&
20479584 983 vm_page_count_min(0));
984263bc
MD
984
985 }
986
987 /*
988 * We don't bother paging objects that are "dead".
989 * Those objects are in a "rundown" state.
990 */
991 if (!swap_pageouts_ok || (object->flags & OBJ_DEAD)) {
b12defdc 992 vm_page_and_queue_spin_lock(m);
027193eb
MD
993 if (m->queue - m->pc == PQ_INACTIVE) {
994 TAILQ_REMOVE(
995 &vm_page_queues[PQ_INACTIVE + q].pl,
996 m, pageq);
997 TAILQ_INSERT_TAIL(
998 &vm_page_queues[PQ_INACTIVE + q].pl,
999 m, pageq);
b12defdc
MD
1000 }
1001 vm_page_and_queue_spin_unlock(m);
e527fb6b 1002 ++vm_swapcache_inactive_heuristic;
b12defdc 1003 vm_page_wakeup(m);
984263bc
MD
1004 continue;
1005 }
1006
1007 /*
b12defdc
MD
1008 * (m) is still busied.
1009 *
984263bc
MD
1010 * The object is already known NOT to be dead. It
1011 * is possible for the vget() to block the whole
1012 * pageout daemon, but the new low-memory handling
1013 * code should prevent it.
1014 *
1015 * The previous code skipped locked vnodes and, worse,
1016 * reordered pages in the queue. This results in
1017 * completely non-deterministic operation because,
1018 * quite often, a vm_fault has initiated an I/O and
1019 * is holding a locked vnode at just the point where
1020 * the pageout daemon is woken up.
1021 *
1022 * We can't wait forever for the vnode lock, we might
1023 * deadlock due to a vn_read() getting stuck in
1024 * vm_wait while holding this vnode. We skip the
1025 * vnode if we can't get it in a reasonable amount
1026 * of time.
5d6a945b
MD
1027 *
1028 * vpfailed is used to (try to) avoid the case where
1029 * a large number of pages are associated with a
1030 * locked vnode, which could cause the pageout daemon
1031 * to stall for an excessive amount of time.
984263bc 1032 */
984263bc 1033 if (object->type == OBJT_VNODE) {
5d6a945b 1034 int flags;
984263bc 1035
5d6a945b
MD
1036 vp = object->handle;
1037 flags = LK_EXCLUSIVE | LK_NOOBJ;
1038 if (vp == vpfailed)
1039 flags |= LK_NOWAIT;
1040 else
1041 flags |= LK_TIMELOCK;
b12defdc
MD
1042 vm_page_hold(m);
1043 vm_page_wakeup(m);
1044
1045 /*
1046 * We have unbusied (m) temporarily so we can
1047 * acquire the vp lock without deadlocking.
1048 * (m) is held to prevent destruction.
1049 */
5d6a945b
MD
1050 if (vget(vp, flags) != 0) {
1051 vpfailed = vp;
984263bc
MD
1052 ++pageout_lock_miss;
1053 if (object->flags & OBJ_MIGHTBEDIRTY)
027193eb 1054 ++*vnodes_skippedp;
b12defdc 1055 vm_page_unhold(m);
984263bc
MD
1056 continue;
1057 }
1058
1059 /*
1060 * The page might have been moved to another
1061 * queue during potential blocking in vget()
1062 * above. The page might have been freed and
1063 * reused for another vnode. The object might
1064 * have been reused for another vnode.
1065 */
027193eb 1066 if (m->queue - m->pc != PQ_INACTIVE ||
984263bc
MD
1067 m->object != object ||
1068 object->handle != vp) {
1069 if (object->flags & OBJ_MIGHTBEDIRTY)
027193eb 1070 ++*vnodes_skippedp;
984263bc 1071 vput(vp);
b12defdc 1072 vm_page_unhold(m);
984263bc
MD
1073 continue;
1074 }
1075
1076 /*
1077 * The page may have been busied during the
1078 * blocking in vput(); We don't move the
1079 * page back onto the end of the queue so that
1080 * statistics are more correct if we don't.
1081 */
b12defdc 1082 if (vm_page_busy_try(m, TRUE)) {
984263bc 1083 vput(vp);
b12defdc 1084 vm_page_unhold(m);
984263bc
MD
1085 continue;
1086 }
b12defdc 1087 vm_page_unhold(m);
984263bc
MD
1088
1089 /*
b12defdc
MD
1090 * (m) is busied again
1091 *
1092 * We own the busy bit and remove our hold
1093 * bit. If the page is still held it
1094 * might be undergoing I/O, so skip it.
984263bc
MD
1095 */
1096 if (m->hold_count) {
b12defdc 1097 vm_page_and_queue_spin_lock(m);
027193eb
MD
1098 if (m->queue - m->pc == PQ_INACTIVE) {
1099 TAILQ_REMOVE(&vm_page_queues[PQ_INACTIVE + q].pl, m, pageq);
1100 TAILQ_INSERT_TAIL(&vm_page_queues[PQ_INACTIVE + q].pl, m, pageq);
b12defdc
MD
1101 }
1102 vm_page_and_queue_spin_unlock(m);
e527fb6b 1103 ++vm_swapcache_inactive_heuristic;
984263bc 1104 if (object->flags & OBJ_MIGHTBEDIRTY)
027193eb 1105 ++*vnodes_skippedp;
b12defdc 1106 vm_page_wakeup(m);
984263bc
MD
1107 vput(vp);
1108 continue;
1109 }
b12defdc 1110 /* (m) is left busied as we fall through */
984263bc
MD
1111 }
1112
1113 /*
b12defdc
MD
1114 * page is busy and not held here.
1115 *
984263bc
MD
1116 * If a page is dirty, then it is either being washed
1117 * (but not yet cleaned) or it is still in the
1118 * laundry. If it is still in the laundry, then we
1119 * start the cleaning operation.
1120 *
20479584
MD
1121 * decrement inactive_shortage on success to account
1122 * for the (future) cleaned page. Otherwise we
1123 * could wind up laundering or cleaning too many
1124 * pages.
984263bc 1125 */
984263bc 1126 if (vm_pageout_clean(m) != 0) {
027193eb 1127 ++delta;
984263bc 1128 --maxlaunder;
c84c24da 1129 }
b12defdc 1130 /* clean ate busy, page no longer accessible */
984263bc
MD
1131 if (vp != NULL)
1132 vput(vp);
b12defdc
MD
1133 } else {
1134 vm_page_wakeup(m);
984263bc
MD
1135 }
1136 }
027193eb
MD
1137 vm_page_queues_spin_lock(PQ_INACTIVE + q);
1138 TAILQ_REMOVE(&vm_page_queues[PQ_INACTIVE + q].pl, &marker, pageq);
1139 vm_page_queues_spin_unlock(PQ_INACTIVE + q);
027193eb
MD
1140 return (delta);
1141}
1142
1143static int
1144vm_pageout_scan_active(int pass, int q,
51c99c61 1145 int avail_shortage, int inactive_shortage,
027193eb
MD
1146 int *recycle_countp)
1147{
1148 struct vm_page marker;
1149 vm_page_t m;
1150 int actcount;
1151 int delta = 0;
51c99c61 1152 int maxscan;
984263bc
MD
1153
1154 /*
20479584
MD
1155 * We want to move pages from the active queue to the inactive
1156 * queue to get the inactive queue to the inactive target. If
1157 * we still have a page shortage from above we try to directly free
1158 * clean pages instead of moving them.
06ecca5a 1159 *
20479584
MD
1160 * If we do still have a shortage we keep track of the number of
1161 * pages we free or cache (recycle_count) as a measure of thrashing
1162 * between the active and inactive queues.
1163 *
51db7ca2
MD
1164 * If we were able to completely satisfy the free+cache targets
1165 * from the inactive pool we limit the number of pages we move
1166 * from the active pool to the inactive pool to 2x the pages we
e6e9a0c3
MD
1167 * had removed from the inactive pool (with a minimum of 1/5 the
1168 * inactive target). If we were not able to completely satisfy
1169 * the free+cache targets we go for the whole target aggressively.
20479584
MD
1170 *
1171 * NOTE: Both variables can end up negative.
1172 * NOTE: We are still in a critical section.
984263bc 1173 */
20479584 1174
027193eb
MD
1175 bzero(&marker, sizeof(marker));
1176 marker.flags = PG_BUSY | PG_FICTITIOUS | PG_MARKER;
1177 marker.queue = PQ_ACTIVE + q;
1178 marker.pc = q;
1179 marker.wire_count = 1;
b12defdc 1180
027193eb
MD
1181 vm_page_queues_spin_lock(PQ_ACTIVE + q);
1182 TAILQ_INSERT_HEAD(&vm_page_queues[PQ_ACTIVE + q].pl, &marker, pageq);
51c99c61 1183 maxscan = vm_page_queues[PQ_ACTIVE + q].lcnt;
027193eb 1184 vm_page_queues_spin_unlock(PQ_ACTIVE + q);
b12defdc
MD
1185
1186 while ((m = TAILQ_NEXT(&marker, pageq)) != NULL &&
51c99c61
MD
1187 maxscan-- > 0 && (avail_shortage - delta > 0 ||
1188 inactive_shortage > 0))
b12defdc
MD
1189 {
1190 vm_page_and_queue_spin_lock(m);
1191 if (m != TAILQ_NEXT(&marker, pageq)) {
1192 vm_page_and_queue_spin_unlock(m);
51c99c61 1193 ++maxscan;
b12defdc
MD
1194 continue;
1195 }
027193eb
MD
1196 KKASSERT(m->queue - m->pc == PQ_ACTIVE);
1197 TAILQ_REMOVE(&vm_page_queues[PQ_ACTIVE + q].pl,
b12defdc 1198 &marker, pageq);
027193eb 1199 TAILQ_INSERT_AFTER(&vm_page_queues[PQ_ACTIVE + q].pl, m,
b12defdc 1200 &marker, pageq);
984263bc 1201
06ecca5a 1202 /*
b12defdc 1203 * Skip marker pages
984263bc 1204 */
b12defdc
MD
1205 if (m->flags & PG_MARKER) {
1206 vm_page_and_queue_spin_unlock(m);
1207 continue;
1208 }
06ecca5a 1209
984263bc 1210 /*
b12defdc
MD
1211 * Try to busy the page. Don't mess with pages which are
1212 * already busy or reorder them in the queue.
984263bc 1213 */
b12defdc
MD
1214 if (vm_page_busy_try(m, TRUE)) {
1215 vm_page_and_queue_spin_unlock(m);
984263bc
MD
1216 continue;
1217 }
1218
1219 /*
b12defdc
MD
1220 * Don't deactivate pages that are held, even if we can
1221 * busy them. (XXX why not?)
1222 */
1223 if (m->hold_count != 0) {
027193eb 1224 TAILQ_REMOVE(&vm_page_queues[PQ_ACTIVE + q].pl,
b12defdc 1225 m, pageq);
027193eb 1226 TAILQ_INSERT_TAIL(&vm_page_queues[PQ_ACTIVE + q].pl,
b12defdc
MD
1227 m, pageq);
1228 vm_page_and_queue_spin_unlock(m);
1229 vm_page_wakeup(m);
1230 continue;
1231 }
1232 vm_page_and_queue_spin_unlock(m);
d2d8515b 1233 lwkt_yield();
b12defdc
MD
1234
1235 /*
1236 * The page has been successfully busied and the page and
1237 * queue are no longer locked.
1238 */
1239
1240 /*
984263bc
MD
1241 * The count for pagedaemon pages is done after checking the
1242 * page for eligibility...
1243 */
12e4aaff 1244 mycpu->gd_cnt.v_pdpages++;
984263bc
MD
1245
1246 /*
20479584
MD
1247 * Check to see "how much" the page has been used and clear
1248 * the tracking access bits. If the object has no references
1249 * don't bother paying the expense.
984263bc
MD
1250 */
1251 actcount = 0;
1252 if (m->object->ref_count != 0) {
20479584
MD
1253 if (m->flags & PG_REFERENCED)
1254 ++actcount;
984263bc
MD
1255 actcount += pmap_ts_referenced(m);
1256 if (actcount) {
1257 m->act_count += ACT_ADVANCE + actcount;
1258 if (m->act_count > ACT_MAX)
1259 m->act_count = ACT_MAX;
1260 }
1261 }
984263bc
MD
1262 vm_page_flag_clear(m, PG_REFERENCED);
1263
1264 /*
20479584 1265 * actcount is only valid if the object ref_count is non-zero.
984263bc 1266 */
20479584 1267 if (actcount && m->object->ref_count != 0) {
b12defdc 1268 vm_page_and_queue_spin_lock(m);
027193eb
MD
1269 if (m->queue - m->pc == PQ_ACTIVE) {
1270 TAILQ_REMOVE(
1271 &vm_page_queues[PQ_ACTIVE + q].pl,
1272 m, pageq);
1273 TAILQ_INSERT_TAIL(
1274 &vm_page_queues[PQ_ACTIVE + q].pl,
1275 m, pageq);
b12defdc
MD
1276 }
1277 vm_page_and_queue_spin_unlock(m);
1278 vm_page_wakeup(m);
984263bc
MD
1279 } else {
1280 m->act_count -= min(m->act_count, ACT_DECLINE);
1281 if (vm_pageout_algorithm ||
1282 m->object->ref_count == 0 ||
20479584
MD
1283 m->act_count < pass + 1
1284 ) {
1285 /*
1286 * Deactivate the page. If we had a
1287 * shortage from our inactive scan try to
1288 * free (cache) the page instead.
e6e9a0c3
MD
1289 *
1290 * Don't just blindly cache the page if
1291 * we do not have a shortage from the
1292 * inactive scan, that could lead to
1293 * gigabytes being moved.
20479584 1294 */
51c99c61
MD
1295 --inactive_shortage;
1296 if (avail_shortage - delta > 0 ||
20479584 1297 m->object->ref_count == 0) {
51c99c61 1298 if (avail_shortage - delta > 0)
027193eb 1299 ++*recycle_countp;
984263bc 1300 vm_page_protect(m, VM_PROT_NONE);
e6e9a0c3 1301 if (m->dirty == 0 &&
51c99c61 1302 avail_shortage - delta > 0) {
984263bc 1303 vm_page_cache(m);
c84c24da 1304 } else {
984263bc 1305 vm_page_deactivate(m);
a491077e 1306 vm_page_wakeup(m);
c84c24da 1307 }
984263bc
MD
1308 } else {
1309 vm_page_deactivate(m);
b12defdc 1310 vm_page_wakeup(m);
984263bc 1311 }
51c99c61 1312 ++delta;
984263bc 1313 } else {
b12defdc 1314 vm_page_and_queue_spin_lock(m);
027193eb 1315 if (m->queue - m->pc == PQ_ACTIVE) {
b12defdc 1316 TAILQ_REMOVE(
027193eb
MD
1317 &vm_page_queues[PQ_ACTIVE + q].pl,
1318 m, pageq);
b12defdc 1319 TAILQ_INSERT_TAIL(
027193eb
MD
1320 &vm_page_queues[PQ_ACTIVE + q].pl,
1321 m, pageq);
b12defdc
MD
1322 }
1323 vm_page_and_queue_spin_unlock(m);
1324 vm_page_wakeup(m);
984263bc
MD
1325 }
1326 }
984263bc
MD
1327 }
1328
984263bc 1329 /*
b12defdc
MD
1330 * Clean out our local marker.
1331 */
027193eb
MD
1332 vm_page_queues_spin_lock(PQ_ACTIVE + q);
1333 TAILQ_REMOVE(&vm_page_queues[PQ_ACTIVE + q].pl, &marker, pageq);
1334 vm_page_queues_spin_unlock(PQ_ACTIVE + q);
1335
1336 return (delta);
1337}
1338
1339/*
1340 * The number of actually free pages can drop down to v_free_reserved,
1341 * we try to build the free count back above v_free_min. Note that
1342 * vm_paging_needed() also returns TRUE if v_free_count is not at
1343 * least v_free_min so that is the minimum we must build the free
1344 * count to.
1345 *
1346 * We use a slightly higher target to improve hysteresis,
1347 * ((v_free_target + v_free_min) / 2). Since v_free_target
1348 * is usually the same as v_cache_min this maintains about
1349 * half the pages in the free queue as are in the cache queue,
1350 * providing pretty good pipelining for pageout operation.
1351 *
1352 * The system operator can manipulate vm.v_cache_min and
1353 * vm.v_free_target to tune the pageout demon. Be sure
1354 * to keep vm.v_free_min < vm.v_free_target.
1355 *
1356 * Note that the original paging target is to get at least
1357 * (free_min + cache_min) into (free + cache). The slightly
1358 * higher target will shift additional pages from cache to free
1359 * without effecting the original paging target in order to
1360 * maintain better hysteresis and not have the free count always
1361 * be dead-on v_free_min.
1362 *
1363 * NOTE: we are still in a critical section.
1364 *
1365 * Pages moved from PQ_CACHE to totally free are not counted in the
1366 * pages_freed counter.
1367 */
1368static void
51c99c61 1369vm_pageout_scan_cache(int avail_shortage, int vnodes_skipped, int recycle_count)
027193eb
MD
1370{
1371 struct vm_pageout_scan_info info;
1372 vm_page_t m;
b12defdc 1373
cd3c66bd
MD
1374 while (vmstats.v_free_count <
1375 (vmstats.v_free_min + vmstats.v_free_target) / 2) {
1376 /*
b12defdc 1377 * This steals some code from vm/vm_page.c
cd3c66bd 1378 */
984263bc 1379 static int cache_rover = 0;
b12defdc
MD
1380
1381 m = vm_page_list_find(PQ_CACHE, cache_rover & PQ_L2_MASK, FALSE);
20479584 1382 if (m == NULL)
984263bc 1383 break;
b12defdc
MD
1384 /* page is returned removed from its queue and spinlocked */
1385 if (vm_page_busy_try(m, TRUE)) {
1386 vm_page_deactivate_locked(m);
1387 vm_page_spin_unlock(m);
984263bc 1388#ifdef INVARIANTS
086c1d7e 1389 kprintf("Warning: busy page %p found in cache\n", m);
984263bc 1390#endif
b12defdc
MD
1391 continue;
1392 }
1393 vm_page_spin_unlock(m);
1394 pagedaemon_wakeup();
d2d8515b 1395 lwkt_yield();
b12defdc
MD
1396
1397 /*
1398 * Page has been successfully busied and it and its queue
1399 * is no longer spinlocked.
1400 */
1401 if ((m->flags & PG_UNMANAGED) ||
1402 m->hold_count ||
1403 m->wire_count) {
984263bc 1404 vm_page_deactivate(m);
b12defdc 1405 vm_page_wakeup(m);
984263bc
MD
1406 continue;
1407 }
17cde63e
MD
1408 KKASSERT((m->flags & PG_MAPPED) == 0);
1409 KKASSERT(m->dirty == 0);
b12defdc 1410 cache_rover += PQ_PRIME2;
984263bc 1411 vm_pageout_page_free(m);
12e4aaff 1412 mycpu->gd_cnt.v_dfree++;
984263bc 1413 }
06ecca5a 1414
984263bc
MD
1415#if !defined(NO_SWAPPING)
1416 /*
1417 * Idle process swapout -- run once per second.
1418 */
1419 if (vm_swap_idle_enabled) {
1420 static long lsec;
1421 if (time_second != lsec) {
1422 vm_pageout_req_swapout |= VM_SWAP_IDLE;
1423 vm_req_vmdaemon();
1424 lsec = time_second;
1425 }
1426 }
1427#endif
1428
1429 /*
1430 * If we didn't get enough free pages, and we have skipped a vnode
1431 * in a writeable object, wakeup the sync daemon. And kick swapout
1432 * if we did not get enough free pages.
1433 */
1434 if (vm_paging_target() > 0) {
20479584 1435 if (vnodes_skipped && vm_page_count_min(0))
418ff780 1436 speedup_syncer();
984263bc
MD
1437#if !defined(NO_SWAPPING)
1438 if (vm_swap_enabled && vm_page_count_target()) {
1439 vm_req_vmdaemon();
1440 vm_pageout_req_swapout |= VM_SWAP_NORMAL;
1441 }
1442#endif
1443 }
1444
1445 /*
20479584
MD
1446 * Handle catastrophic conditions. Under good conditions we should
1447 * be at the target, well beyond our minimum. If we could not even
1448 * reach our minimum the system is under heavy stress.
1449 *
1450 * Determine whether we have run out of memory. This occurs when
1451 * swap_pager_full is TRUE and the only pages left in the page
1452 * queues are dirty. We will still likely have page shortages.
c84c24da
MD
1453 *
1454 * - swap_pager_full is set if insufficient swap was
1455 * available to satisfy a requested pageout.
1456 *
20479584
MD
1457 * - the inactive queue is bloated (4 x size of active queue),
1458 * meaning it is unable to get rid of dirty pages and.
c84c24da 1459 *
20479584
MD
1460 * - vm_page_count_min() without counting pages recycled from the
1461 * active queue (recycle_count) means we could not recover
1462 * enough pages to meet bare minimum needs. This test only
1463 * works if the inactive queue is bloated.
c84c24da 1464 *
51c99c61 1465 * - due to a positive avail_shortage we shifted the remaining
20479584
MD
1466 * dirty pages from the active queue to the inactive queue
1467 * trying to find clean ones to free.
984263bc 1468 */
20479584 1469 if (swap_pager_full && vm_page_count_min(recycle_count))
c84c24da 1470 kprintf("Warning: system low on memory+swap!\n");
20479584
MD
1471 if (swap_pager_full && vm_page_count_min(recycle_count) &&
1472 vmstats.v_inactive_count > vmstats.v_active_count * 4 &&
51c99c61 1473 avail_shortage > 0) {
20479584
MD
1474 /*
1475 * Kill something.
1476 */
8fa76237
MD
1477 info.bigproc = NULL;
1478 info.bigsize = 0;
1479 allproc_scan(vm_pageout_scan_callback, &info);
1480 if (info.bigproc != NULL) {
1481 killproc(info.bigproc, "out of swap space");
1482 info.bigproc->p_nice = PRIO_MIN;
08f2f1bb
SS
1483 info.bigproc->p_usched->resetpriority(
1484 FIRST_LWP_IN_PROC(info.bigproc));
12e4aaff 1485 wakeup(&vmstats.v_free_count);
8fa76237 1486 PRELE(info.bigproc);
984263bc
MD
1487 }
1488 }
1489}
1490
99ad9bc4 1491/*
b12defdc 1492 * The caller must hold proc_token.
99ad9bc4 1493 */
8fa76237
MD
1494static int
1495vm_pageout_scan_callback(struct proc *p, void *data)
1496{
1497 struct vm_pageout_scan_info *info = data;
1498 vm_offset_t size;
1499
1500 /*
20479584
MD
1501 * Never kill system processes or init. If we have configured swap
1502 * then try to avoid killing low-numbered pids.
8fa76237 1503 */
4643740a 1504 if ((p->p_flags & P_SYSTEM) || (p->p_pid == 1) ||
8fa76237
MD
1505 ((p->p_pid < 48) && (vm_swap_size != 0))) {
1506 return (0);
1507 }
1508
1509 /*
1510 * if the process is in a non-running type state,
1511 * don't touch it.
1512 */
20479584 1513 if (p->p_stat != SACTIVE && p->p_stat != SSTOP)
8fa76237 1514 return (0);
8fa76237
MD
1515
1516 /*
20479584
MD
1517 * Get the approximate process size. Note that anonymous pages
1518 * with backing swap will be counted twice, but there should not
1519 * be too many such pages due to the stress the VM system is
1520 * under at this point.
8fa76237 1521 */
20479584 1522 size = vmspace_anonymous_count(p->p_vmspace) +
8fa76237
MD
1523 vmspace_swap_count(p->p_vmspace);
1524
1525 /*
1526 * If the this process is bigger than the biggest one
1527 * remember it.
1528 */
20479584 1529 if (info->bigsize < size) {
8fa76237
MD
1530 if (info->bigproc)
1531 PRELE(info->bigproc);
1532 PHOLD(p);
1533 info->bigproc = p;
1534 info->bigsize = size;
1535 }
d2d8515b 1536 lwkt_yield();
8fa76237
MD
1537 return(0);
1538}
1539
984263bc
MD
1540/*
1541 * This routine tries to maintain the pseudo LRU active queue,
1542 * so that during long periods of time where there is no paging,
1543 * that some statistic accumulation still occurs. This code
1544 * helps the situation where paging just starts to occur.
1545 */
1546static void
027193eb 1547vm_pageout_page_stats(int q)
984263bc 1548{
984263bc 1549 static int fullintervalcount = 0;
b12defdc
MD
1550 struct vm_page marker;
1551 vm_page_t m;
1552 int pcount, tpcount; /* Number of pages to check */
984263bc 1553 int page_shortage;
984263bc 1554
b12defdc
MD
1555 page_shortage = (vmstats.v_inactive_target + vmstats.v_cache_max +
1556 vmstats.v_free_min) -
1557 (vmstats.v_free_count + vmstats.v_inactive_count +
1558 vmstats.v_cache_count);
984263bc
MD
1559
1560 if (page_shortage <= 0)
1561 return;
1562
51c99c61 1563 pcount = vm_page_queues[PQ_ACTIVE + q].lcnt;
984263bc
MD
1564 fullintervalcount += vm_pageout_stats_interval;
1565 if (fullintervalcount < vm_pageout_full_stats_interval) {
51c99c61
MD
1566 tpcount = (vm_pageout_stats_max * pcount) /
1567 vmstats.v_page_count + 1;
984263bc
MD
1568 if (pcount > tpcount)
1569 pcount = tpcount;
1570 } else {
1571 fullintervalcount = 0;
1572 }
1573
b12defdc
MD
1574 bzero(&marker, sizeof(marker));
1575 marker.flags = PG_BUSY | PG_FICTITIOUS | PG_MARKER;
027193eb
MD
1576 marker.queue = PQ_ACTIVE + q;
1577 marker.pc = q;
b12defdc
MD
1578 marker.wire_count = 1;
1579
027193eb
MD
1580 vm_page_queues_spin_lock(PQ_ACTIVE + q);
1581 TAILQ_INSERT_HEAD(&vm_page_queues[PQ_ACTIVE + q].pl, &marker, pageq);
1582 vm_page_queues_spin_unlock(PQ_ACTIVE + q);
b12defdc
MD
1583
1584 while ((m = TAILQ_NEXT(&marker, pageq)) != NULL &&
1585 pcount-- > 0)
1586 {
984263bc
MD
1587 int actcount;
1588
b12defdc
MD
1589 vm_page_and_queue_spin_lock(m);
1590 if (m != TAILQ_NEXT(&marker, pageq)) {
1591 vm_page_and_queue_spin_unlock(m);
1592 ++pcount;
1593 continue;
984263bc 1594 }
027193eb
MD
1595 KKASSERT(m->queue - m->pc == PQ_ACTIVE);
1596 TAILQ_REMOVE(&vm_page_queues[PQ_ACTIVE + q].pl, &marker, pageq);
1597 TAILQ_INSERT_AFTER(&vm_page_queues[PQ_ACTIVE + q].pl, m,
b12defdc 1598 &marker, pageq);
984263bc 1599
984263bc 1600 /*
b12defdc 1601 * Ignore markers
984263bc 1602 */
b12defdc
MD
1603 if (m->flags & PG_MARKER) {
1604 vm_page_and_queue_spin_unlock(m);
984263bc
MD
1605 continue;
1606 }
1607
b12defdc
MD
1608 /*
1609 * Ignore pages we can't busy
1610 */
1611 if (vm_page_busy_try(m, TRUE)) {
1612 vm_page_and_queue_spin_unlock(m);
1613 continue;
1614 }
1615 vm_page_and_queue_spin_unlock(m);
027193eb 1616 KKASSERT(m->queue - m->pc == PQ_ACTIVE);
b12defdc
MD
1617
1618 /*
1619 * We now have a safely busied page, the page and queue
1620 * spinlocks have been released.
1621 *
1622 * Ignore held pages
1623 */
1624 if (m->hold_count) {
1625 vm_page_wakeup(m);
1626 continue;
1627 }
1628
1629 /*
1630 * Calculate activity
1631 */
984263bc
MD
1632 actcount = 0;
1633 if (m->flags & PG_REFERENCED) {
1634 vm_page_flag_clear(m, PG_REFERENCED);
1635 actcount += 1;
1636 }
984263bc 1637 actcount += pmap_ts_referenced(m);
b12defdc
MD
1638
1639 /*
1640 * Update act_count and move page to end of queue.
1641 */
984263bc
MD
1642 if (actcount) {
1643 m->act_count += ACT_ADVANCE + actcount;
1644 if (m->act_count > ACT_MAX)
1645 m->act_count = ACT_MAX;
b12defdc 1646 vm_page_and_queue_spin_lock(m);
027193eb
MD
1647 if (m->queue - m->pc == PQ_ACTIVE) {
1648 TAILQ_REMOVE(
1649 &vm_page_queues[PQ_ACTIVE + q].pl,
1650 m, pageq);
1651 TAILQ_INSERT_TAIL(
1652 &vm_page_queues[PQ_ACTIVE + q].pl,
1653 m, pageq);
984263bc 1654 }
b12defdc
MD
1655 vm_page_and_queue_spin_unlock(m);
1656 vm_page_wakeup(m);
1657 continue;
984263bc
MD
1658 }
1659
b12defdc
MD
1660 if (m->act_count == 0) {
1661 /*
1662 * We turn off page access, so that we have
1663 * more accurate RSS stats. We don't do this
1664 * in the normal page deactivation when the
1665 * system is loaded VM wise, because the
1666 * cost of the large number of page protect
1667 * operations would be higher than the value
1668 * of doing the operation.
1669 *
1670 * We use the marker to save our place so
1671 * we can release the spin lock. both (m)
1672 * and (next) will be invalid.
1673 */
1674 vm_page_protect(m, VM_PROT_NONE);
1675 vm_page_deactivate(m);
1676 } else {
1677 m->act_count -= min(m->act_count, ACT_DECLINE);
1678 vm_page_and_queue_spin_lock(m);
027193eb
MD
1679 if (m->queue - m->pc == PQ_ACTIVE) {
1680 TAILQ_REMOVE(
1681 &vm_page_queues[PQ_ACTIVE + q].pl,
1682 m, pageq);
1683 TAILQ_INSERT_TAIL(
1684 &vm_page_queues[PQ_ACTIVE + q].pl,
1685 m, pageq);
b12defdc
MD
1686 }
1687 vm_page_and_queue_spin_unlock(m);
1688 }
1689 vm_page_wakeup(m);
984263bc 1690 }
b12defdc
MD
1691
1692 /*
1693 * Remove our local marker
1694 */
027193eb
MD
1695 vm_page_queues_spin_lock(PQ_ACTIVE + q);
1696 TAILQ_REMOVE(&vm_page_queues[PQ_ACTIVE + q].pl, &marker, pageq);
1697 vm_page_queues_spin_unlock(PQ_ACTIVE + q);
984263bc
MD
1698}
1699
1700static int
57e43348 1701vm_pageout_free_page_calc(vm_size_t count)
984263bc 1702{
12e4aaff 1703 if (count < vmstats.v_page_count)
984263bc
MD
1704 return 0;
1705 /*
1706 * free_reserved needs to include enough for the largest swap pager
1707 * structures plus enough for any pv_entry structs when paging.
0a4d4828
MD
1708 *
1709 * v_free_min normal allocations
1710 * v_free_reserved system allocations
1711 * v_pageout_free_min allocations by pageout daemon
1712 * v_interrupt_free_min low level allocations (e.g swap structures)
984263bc 1713 */
12e4aaff 1714 if (vmstats.v_page_count > 1024)
0a4d4828 1715 vmstats.v_free_min = 64 + (vmstats.v_page_count - 1024) / 200;
984263bc 1716 else
0a4d4828
MD
1717 vmstats.v_free_min = 64;
1718 vmstats.v_free_reserved = vmstats.v_free_min * 4 / 8 + 7;
1719 vmstats.v_free_severe = vmstats.v_free_min * 4 / 8 + 0;
1720 vmstats.v_pageout_free_min = vmstats.v_free_min * 2 / 8 + 7;
1721 vmstats.v_interrupt_free_min = vmstats.v_free_min * 1 / 8 + 7;
1722
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1723 return 1;
1724}
1725
1726
1727/*
20479584 1728 * vm_pageout is the high level pageout daemon.
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1729 *
1730 * No requirements.
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1731 */
1732static void
cd8ab232 1733vm_pageout_thread(void)
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1734{
1735 int pass;
027193eb 1736 int q;
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1737
1738 /*
1739 * Initialize some paging parameters.
1740 */
4ecf7cc9 1741 curthread->td_flags |= TDF_SYSTHREAD;
984263bc 1742
12e4aaff 1743 if (vmstats.v_page_count < 2000)
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1744 vm_pageout_page_count = 8;
1745
12e4aaff 1746 vm_pageout_free_page_calc(vmstats.v_page_count);
20479584 1747
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1748 /*
1749 * v_free_target and v_cache_min control pageout hysteresis. Note
1750 * that these are more a measure of the VM cache queue hysteresis
1751 * then the VM free queue. Specifically, v_free_target is the
1752 * high water mark (free+cache pages).
1753 *
1754 * v_free_reserved + v_cache_min (mostly means v_cache_min) is the
1755 * low water mark, while v_free_min is the stop. v_cache_min must
1756 * be big enough to handle memory needs while the pageout daemon
1757 * is signalled and run to free more pages.
1758 */
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1759 if (vmstats.v_free_count > 6144)
1760 vmstats.v_free_target = 4 * vmstats.v_free_min + vmstats.v_free_reserved;
984263bc 1761 else
12e4aaff 1762 vmstats.v_free_target = 2 * vmstats.v_free_min + vmstats.v_free_reserved;
984263bc 1763
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1764 /*
1765 * NOTE: With the new buffer cache b_act_count we want the default
1766 * inactive target to be a percentage of available memory.
1767 *
1768 * The inactive target essentially determines the minimum
1769 * number of 'temporary' pages capable of caching one-time-use
1770 * files when the VM system is otherwise full of pages
1771 * belonging to multi-time-use files or active program data.
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1772 *
1773 * NOTE: The inactive target is aggressively persued only if the
1774 * inactive queue becomes too small. If the inactive queue
1775 * is large enough to satisfy page movement to free+cache
1776 * then it is repopulated more slowly from the active queue.
e15708fc 1777 * This allows a general inactive_target default to be set.
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1778 *
1779 * There is an issue here for processes which sit mostly idle
1780 * 'overnight', such as sshd, tcsh, and X. Any movement from
1781 * the active queue will eventually cause such pages to
1782 * recycle eventually causing a lot of paging in the morning.
1783 * To reduce the incidence of this pages cycled out of the
1784 * buffer cache are moved directly to the inactive queue if
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1785 * they were only used once or twice.
1786 *
1787 * The vfs.vm_cycle_point sysctl can be used to adjust this.
1788 * Increasing the value (up to 64) increases the number of
1789 * buffer recyclements which go directly to the inactive queue.
0e8bd897 1790 */
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1791 if (vmstats.v_free_count > 2048) {
1792 vmstats.v_cache_min = vmstats.v_free_target;
1793 vmstats.v_cache_max = 2 * vmstats.v_cache_min;
984263bc 1794 } else {
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1795 vmstats.v_cache_min = 0;
1796 vmstats.v_cache_max = 0;
984263bc 1797 }
e15708fc 1798 vmstats.v_inactive_target = vmstats.v_free_count / 4;
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1799
1800 /* XXX does not really belong here */
1801 if (vm_page_max_wired == 0)
12e4aaff 1802 vm_page_max_wired = vmstats.v_free_count / 3;
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1803
1804 if (vm_pageout_stats_max == 0)
12e4aaff 1805 vm_pageout_stats_max = vmstats.v_free_target;
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1806
1807 /*
1808 * Set interval in seconds for stats scan.
1809 */
1810 if (vm_pageout_stats_interval == 0)
1811 vm_pageout_stats_interval = 5;
1812 if (vm_pageout_full_stats_interval == 0)
1813 vm_pageout_full_stats_interval = vm_pageout_stats_interval * 4;
1814
1815
1816 /*
1817 * Set maximum free per pass
1818 */
1819 if (vm_pageout_stats_free_max == 0)
1820 vm_pageout_stats_free_max = 5;
1821
1822 swap_pager_swap_init();
1823 pass = 0;
20479584 1824
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1825 /*
1826 * The pageout daemon is never done, so loop forever.
1827 */
1828 while (TRUE) {
1829 int error;
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1830 int delta1;
1831 int delta2;
51c99c61 1832 int avail_shortage;
027193eb 1833 int inactive_shortage;
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1834 int vnodes_skipped = 0;
1835 int recycle_count = 0;
1836 int tmp;
984263bc 1837
12d8aca7 1838 /*
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1839 * Wait for an action request. If we timeout check to
1840 * see if paging is needed (in case the normal wakeup
1841 * code raced us).
12d8aca7 1842 */
20479584 1843 if (vm_pages_needed == 0) {
984263bc 1844 error = tsleep(&vm_pages_needed,
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1845 0, "psleep",
1846 vm_pageout_stats_interval * hz);
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1847 if (error &&
1848 vm_paging_needed() == 0 &&
1849 vm_pages_needed == 0) {
51c99c61 1850 for (q = 0; q < PQ_L2_SIZE; ++q)
027193eb 1851 vm_pageout_page_stats(q);
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1852 continue;
1853 }
20479584 1854 vm_pages_needed = 1;
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1855 }
1856
20479584 1857 mycpu->gd_cnt.v_pdwakeups++;
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1858
1859 /*
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1860 * Do whatever cleanup that the pmap code can.
1861 */
1862 pmap_collect();
1863
1864 /*
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1865 * Scan for pageout. Try to avoid thrashing the system
1866 * with activity.
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1867 *
1868 * Calculate our target for the number of free+cache pages we
1869 * want to get to. This is higher then the number that causes
1870 * allocations to stall (severe) in order to provide hysteresis,
1871 * and if we don't make it all the way but get to the minimum
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1872 * we're happy. Goose it a bit if there are multipler
1873 * requests for memory.
027193eb 1874 */
51c99c61 1875 avail_shortage = vm_paging_target() + vm_pageout_deficit;
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1876 vm_pageout_deficit = 0;
1877 delta1 = 0;
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1878 if (avail_shortage > 0) {
1879 for (q = 0; q < PQ_L2_SIZE; ++q) {
1880 delta1 += vm_pageout_scan_inactive(
1881 pass, q,
1882 PQAVERAGE(avail_shortage),
1883 &vnodes_skipped);
1884 }
1885 avail_shortage -= delta1;
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1886 }
1887
1888 /*
1889 * Figure out how many active pages we must deactivate. If
1890 * we were able to reach our target with just the inactive
1891 * scan above we limit the number of active pages we
1892 * deactivate to reduce unnecessary work.
1893 */
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1894 inactive_shortage = vmstats.v_inactive_target -
1895 vmstats.v_inactive_count;
027193eb 1896
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1897 /*
1898 * If we were unable to free sufficient inactive pages to
1899 * satisfy the free/cache queue requirements then simply
1900 * reaching the inactive target may not be good enough.
1901 * Try to deactivate pages in excess of the target based
1902 * on the shortfall.
1903 *
1904 * However to prevent thrashing the VM system do not
1905 * deactivate more than an additional 1/10 the inactive
1906 * target's worth of active pages.
1907 */
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1908 if (avail_shortage > 0) {
1909 tmp = avail_shortage * 2;
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1910 if (tmp > vmstats.v_inactive_target / 10)
1911 tmp = vmstats.v_inactive_target / 10;
51c99c61 1912 inactive_shortage += tmp;
3038a8ca 1913 }
027193eb 1914
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1915 if (avail_shortage > 0 || inactive_shortage > 0) {
1916 delta2 = 0;
1917 for (q = 0; q < PQ_L2_SIZE; ++q) {
1918 delta2 += vm_pageout_scan_active(
1919 pass, q,
1920 PQAVERAGE(avail_shortage),
1921 PQAVERAGE(inactive_shortage),
1922 &recycle_count);
1923 }
1924 inactive_shortage -= delta2;
1925 avail_shortage -= delta2;
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1926 }
1927
1928 /*
1929 * Finally free enough cache pages to meet our free page
1930 * requirement and take more drastic measures if we are
1931 * still in trouble.
1932 */
51c99c61 1933 vm_pageout_scan_cache(avail_shortage, vnodes_skipped,
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1934 recycle_count);
1935
1936 /*
1937 * Wait for more work.
20479584 1938 */
51c99c61 1939 if (avail_shortage > 0) {
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1940 ++pass;
1941 if (swap_pager_full) {
1942 /*
1943 * Running out of memory, catastrophic back-off
1944 * to one-second intervals.
1945 */
1946 tsleep(&vm_pages_needed, 0, "pdelay", hz);
1947 } else if (pass < 10 && vm_pages_needed > 1) {
1948 /*
1949 * Normal operation, additional processes
1950 * have already kicked us. Retry immediately.
1951 */
1952 } else if (pass < 10) {
1953 /*
1954 * Normal operation, fewer processes. Delay
1955 * a bit but allow wakeups.
1956 */
1957 vm_pages_needed = 0;
1958 tsleep(&vm_pages_needed, 0, "pdelay", hz / 10);
1959 vm_pages_needed = 1;
1960 } else {
1961 /*
1962 * We've taken too many passes, forced delay.
1963 */
1964 tsleep(&vm_pages_needed, 0, "pdelay", hz / 10);
1965 }
1966 } else {
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1967 /*
1968 * Interlocked wakeup of waiters (non-optional)
1969 */
20479584 1970 pass = 0;
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1971 if (vm_pages_needed && !vm_page_count_min(0)) {
1972 wakeup(&vmstats.v_free_count);
1973 vm_pages_needed = 0;
1974 }
20479584 1975 }
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1976 }
1977}
1978
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1979static struct kproc_desc page_kp = {
1980 "pagedaemon",
1981 vm_pageout_thread,
1982 &pagethread
1983};
1984SYSINIT(pagedaemon, SI_SUB_KTHREAD_PAGE, SI_ORDER_FIRST, kproc_start, &page_kp)
1985
1986
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1987/*
1988 * Called after allocating a page out of the cache or free queue
1989 * to possibly wake the pagedaemon up to replentish our supply.
1990 *
1991 * We try to generate some hysteresis by waking the pagedaemon up
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1992 * when our free+cache pages go below the free_min+cache_min level.
1993 * The pagedaemon tries to get the count back up to at least the
1994 * minimum, and through to the target level if possible.
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1995 *
1996 * If the pagedaemon is already active bump vm_pages_needed as a hint
1997 * that there are even more requests pending.
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1998 *
1999 * SMP races ok?
2000 * No requirements.
20479584 2001 */
984263bc 2002void
57e43348 2003pagedaemon_wakeup(void)
984263bc 2004{
1bfac262 2005 if (vm_paging_needed() && curthread != pagethread) {
20479584 2006 if (vm_pages_needed == 0) {
1bfac262 2007 vm_pages_needed = 1; /* SMP race ok */
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2008 wakeup(&vm_pages_needed);
2009 } else if (vm_page_count_min(0)) {
1bfac262 2010 ++vm_pages_needed; /* SMP race ok */
20479584 2011 }
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2012 }
2013}
2014
2015#if !defined(NO_SWAPPING)
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2016
2017/*
2018 * SMP races ok?
2019 * No requirements.
2020 */
984263bc 2021static void
57e43348 2022vm_req_vmdaemon(void)
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MD
2023{
2024 static int lastrun = 0;
2025
2026 if ((ticks > (lastrun + hz)) || (ticks < lastrun)) {
2027 wakeup(&vm_daemon_needed);
2028 lastrun = ticks;
2029 }
2030}
2031
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2032static int vm_daemon_callback(struct proc *p, void *data __unused);
2033
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2034/*
2035 * No requirements.
2036 */
984263bc 2037static void
57e43348 2038vm_daemon(void)
984263bc 2039{
99ad9bc4 2040 /*
b12defdc 2041 * XXX vm_daemon_needed specific token?
99ad9bc4 2042 */
984263bc 2043 while (TRUE) {
377d4740 2044 tsleep(&vm_daemon_needed, 0, "psleep", 0);
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2045 if (vm_pageout_req_swapout) {
2046 swapout_procs(vm_pageout_req_swapout);
2047 vm_pageout_req_swapout = 0;
2048 }
2049 /*
2050 * scan the processes for exceeding their rlimits or if
2051 * process is swapped out -- deactivate pages
2052 */
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2053 allproc_scan(vm_daemon_callback, NULL);
2054 }
2055}
984263bc 2056
99ad9bc4 2057/*
b12defdc 2058 * Caller must hold proc_token.
99ad9bc4 2059 */
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2060static int
2061vm_daemon_callback(struct proc *p, void *data __unused)
2062{
2063 vm_pindex_t limit, size;
984263bc 2064
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2065 /*
2066 * if this is a system process or if we have already
2067 * looked at this process, skip it.
2068 */
4643740a 2069 if (p->p_flags & (P_SYSTEM | P_WEXIT))
8fa76237 2070 return (0);
984263bc 2071
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2072 /*
2073 * if the process is in a non-running type state,
2074 * don't touch it.
2075 */
164b8401 2076 if (p->p_stat != SACTIVE && p->p_stat != SSTOP)
8fa76237 2077 return (0);
984263bc 2078
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2079 /*
2080 * get a limit
2081 */
2082 limit = OFF_TO_IDX(qmin(p->p_rlimit[RLIMIT_RSS].rlim_cur,
2083 p->p_rlimit[RLIMIT_RSS].rlim_max));
2084
2085 /*
2086 * let processes that are swapped out really be
2087 * swapped out. Set the limit to nothing to get as
2088 * many pages out to swap as possible.
2089 */
4643740a 2090 if (p->p_flags & P_SWAPPEDOUT)
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2091 limit = 0;
2092
b12defdc 2093 lwkt_gettoken(&p->p_vmspace->vm_map.token);
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MD
2094 size = vmspace_resident_count(p->p_vmspace);
2095 if (limit >= 0 && size >= limit) {
b12defdc 2096 vm_pageout_map_deactivate_pages(&p->p_vmspace->vm_map, limit);
984263bc 2097 }
b12defdc 2098 lwkt_reltoken(&p->p_vmspace->vm_map.token);
8fa76237 2099 return (0);
984263bc 2100}
8fa76237 2101
984263bc 2102#endif