FreeBSD/Linux Kernel Cross Reference
sys/vm/vm_glue.c
1 /*
2 * Copyright (c) 1991, 1993
3 * The Regents of the University of California. All rights reserved.
4 *
5 * This code is derived from software contributed to Berkeley by
6 * The Mach Operating System project at Carnegie-Mellon University.
7 *
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted provided that the following conditions
10 * are met:
11 * 1. Redistributions of source code must retain the above copyright
12 * notice, this list of conditions and the following disclaimer.
13 * 2. Redistributions in binary form must reproduce the above copyright
14 * notice, this list of conditions and the following disclaimer in the
15 * documentation and/or other materials provided with the distribution.
16 * 3. All advertising materials mentioning features or use of this software
17 * must display the following acknowledgement:
18 * This product includes software developed by the University of
19 * California, Berkeley and its contributors.
20 * 4. Neither the name of the University nor the names of its contributors
21 * may be used to endorse or promote products derived from this software
22 * without specific prior written permission.
23 *
24 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
25 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
26 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
27 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
28 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
29 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
30 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
31 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
32 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
33 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
34 * SUCH DAMAGE.
35 *
36 * from: @(#)vm_glue.c 8.6 (Berkeley) 1/5/94
37 *
38 *
39 * Copyright (c) 1987, 1990 Carnegie-Mellon University.
40 * All rights reserved.
41 *
42 * Permission to use, copy, modify and distribute this software and
43 * its documentation is hereby granted, provided that both the copyright
44 * notice and this permission notice appear in all copies of the
45 * software, derivative works or modified versions, and any portions
46 * thereof, and that both notices appear in supporting documentation.
47 *
48 * CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS"
49 * CONDITION. CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND
50 * FOR ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
51 *
52 * Carnegie Mellon requests users of this software to return to
53 *
54 * Software Distribution Coordinator or Software.Distribution@CS.CMU.EDU
55 * School of Computer Science
56 * Carnegie Mellon University
57 * Pittsburgh PA 15213-3890
58 *
59 * any improvements or extensions that they make and grant Carnegie the
60 * rights to redistribute these changes.
61 *
62 * $FreeBSD: releng/5.0/sys/vm/vm_glue.c 105695 2002-10-22 14:31:32Z jhb $
63 */
64
65 #include "opt_vm.h"
66
67 #include <sys/param.h>
68 #include <sys/systm.h>
69 #include <sys/lock.h>
70 #include <sys/mutex.h>
71 #include <sys/proc.h>
72 #include <sys/resourcevar.h>
73 #include <sys/shm.h>
74 #include <sys/vmmeter.h>
75 #include <sys/sx.h>
76 #include <sys/sysctl.h>
77
78 #include <sys/kernel.h>
79 #include <sys/ktr.h>
80 #include <sys/unistd.h>
81
82 #include <machine/limits.h>
83
84 #include <vm/vm.h>
85 #include <vm/vm_param.h>
86 #include <vm/pmap.h>
87 #include <vm/vm_map.h>
88 #include <vm/vm_page.h>
89 #include <vm/vm_pageout.h>
90 #include <vm/vm_object.h>
91 #include <vm/vm_kern.h>
92 #include <vm/vm_extern.h>
93 #include <vm/vm_pager.h>
94
95 #include <sys/user.h>
96
97 extern int maxslp;
98
99 /*
100 * System initialization
101 *
102 * Note: proc0 from proc.h
103 */
104 static void vm_init_limits(void *);
105 SYSINIT(vm_limits, SI_SUB_VM_CONF, SI_ORDER_FIRST, vm_init_limits, &proc0)
106
107 /*
108 * THIS MUST BE THE LAST INITIALIZATION ITEM!!!
109 *
110 * Note: run scheduling should be divorced from the vm system.
111 */
112 static void scheduler(void *);
113 SYSINIT(scheduler, SI_SUB_RUN_SCHEDULER, SI_ORDER_FIRST, scheduler, NULL)
114
115 #ifndef NO_SWAPPING
116 static void swapout(struct proc *);
117 static void vm_proc_swapin(struct proc *p);
118 static void vm_proc_swapout(struct proc *p);
119 #endif
120
121 /*
122 * MPSAFE
123 */
124 int
125 kernacc(addr, len, rw)
126 caddr_t addr;
127 int len, rw;
128 {
129 boolean_t rv;
130 vm_offset_t saddr, eaddr;
131 vm_prot_t prot;
132
133 KASSERT((rw & ~VM_PROT_ALL) == 0,
134 ("illegal ``rw'' argument to kernacc (%x)\n", rw));
135 prot = rw;
136 saddr = trunc_page((vm_offset_t)addr);
137 eaddr = round_page((vm_offset_t)addr + len);
138 rv = vm_map_check_protection(kernel_map, saddr, eaddr, prot);
139 return (rv == TRUE);
140 }
141
142 /*
143 * MPSAFE
144 */
145 int
146 useracc(addr, len, rw)
147 caddr_t addr;
148 int len, rw;
149 {
150 boolean_t rv;
151 vm_prot_t prot;
152 vm_map_t map;
153
154 KASSERT((rw & ~VM_PROT_ALL) == 0,
155 ("illegal ``rw'' argument to useracc (%x)\n", rw));
156 prot = rw;
157 map = &curproc->p_vmspace->vm_map;
158 if ((vm_offset_t)addr + len > vm_map_max(map) ||
159 (vm_offset_t)addr + len < (vm_offset_t)addr) {
160 return (FALSE);
161 }
162 rv = vm_map_check_protection(map, trunc_page((vm_offset_t)addr),
163 round_page((vm_offset_t)addr + len), prot);
164 return (rv == TRUE);
165 }
166
167 /*
168 * MPSAFE
169 */
170 void
171 vslock(addr, len)
172 caddr_t addr;
173 u_int len;
174 {
175
176 vm_map_wire(&curproc->p_vmspace->vm_map, trunc_page((vm_offset_t)addr),
177 round_page((vm_offset_t)addr + len), FALSE);
178 }
179
180 /*
181 * MPSAFE
182 */
183 void
184 vsunlock(addr, len)
185 caddr_t addr;
186 u_int len;
187 {
188
189 vm_map_unwire(&curproc->p_vmspace->vm_map,
190 trunc_page((vm_offset_t)addr),
191 round_page((vm_offset_t)addr + len), FALSE);
192 }
193
194 /*
195 * Create the U area for a new process.
196 * This routine directly affects the fork perf for a process.
197 */
198 void
199 vm_proc_new(struct proc *p)
200 {
201 vm_page_t ma[UAREA_PAGES];
202 vm_object_t upobj;
203 vm_offset_t up;
204 vm_page_t m;
205 u_int i;
206
207 /*
208 * Allocate object for the upage.
209 */
210 upobj = vm_object_allocate(OBJT_DEFAULT, UAREA_PAGES);
211 p->p_upages_obj = upobj;
212
213 /*
214 * Get a kernel virtual address for the U area for this process.
215 */
216 up = kmem_alloc_nofault(kernel_map, UAREA_PAGES * PAGE_SIZE);
217 if (up == 0)
218 panic("vm_proc_new: upage allocation failed");
219 p->p_uarea = (struct user *)up;
220
221 for (i = 0; i < UAREA_PAGES; i++) {
222 /*
223 * Get a uarea page.
224 */
225 m = vm_page_grab(upobj, i,
226 VM_ALLOC_NORMAL | VM_ALLOC_RETRY | VM_ALLOC_WIRED);
227 ma[i] = m;
228
229 vm_page_wakeup(m);
230 vm_page_flag_clear(m, PG_ZERO);
231 m->valid = VM_PAGE_BITS_ALL;
232 }
233
234 /*
235 * Enter the pages into the kernel address space.
236 */
237 pmap_qenter(up, ma, UAREA_PAGES);
238 }
239
240 /*
241 * Dispose the U area for a process that has exited.
242 * This routine directly impacts the exit perf of a process.
243 * XXX proc_zone is marked UMA_ZONE_NOFREE, so this should never be called.
244 */
245 void
246 vm_proc_dispose(struct proc *p)
247 {
248 vm_object_t upobj;
249 vm_offset_t up;
250 vm_page_t m;
251
252 upobj = p->p_upages_obj;
253 if (upobj->resident_page_count != UAREA_PAGES)
254 panic("vm_proc_dispose: incorrect number of pages in upobj");
255 vm_page_lock_queues();
256 while ((m = TAILQ_FIRST(&upobj->memq)) != NULL) {
257 vm_page_busy(m);
258 vm_page_unwire(m, 0);
259 vm_page_free(m);
260 }
261 vm_page_unlock_queues();
262 up = (vm_offset_t)p->p_uarea;
263 pmap_qremove(up, UAREA_PAGES);
264 kmem_free(kernel_map, up, UAREA_PAGES * PAGE_SIZE);
265 vm_object_deallocate(upobj);
266 }
267
268 #ifndef NO_SWAPPING
269 /*
270 * Allow the U area for a process to be prejudicially paged out.
271 */
272 static void
273 vm_proc_swapout(struct proc *p)
274 {
275 vm_object_t upobj;
276 vm_offset_t up;
277 vm_page_t m;
278
279 upobj = p->p_upages_obj;
280 if (upobj->resident_page_count != UAREA_PAGES)
281 panic("vm_proc_dispose: incorrect number of pages in upobj");
282 vm_page_lock_queues();
283 TAILQ_FOREACH(m, &upobj->memq, listq) {
284 vm_page_dirty(m);
285 vm_page_unwire(m, 0);
286 }
287 vm_page_unlock_queues();
288 up = (vm_offset_t)p->p_uarea;
289 pmap_qremove(up, UAREA_PAGES);
290 }
291
292 /*
293 * Bring the U area for a specified process back in.
294 */
295 static void
296 vm_proc_swapin(struct proc *p)
297 {
298 vm_page_t ma[UAREA_PAGES];
299 vm_object_t upobj;
300 vm_offset_t up;
301 vm_page_t m;
302 int rv;
303 int i;
304
305 upobj = p->p_upages_obj;
306 for (i = 0; i < UAREA_PAGES; i++) {
307 m = vm_page_grab(upobj, i, VM_ALLOC_NORMAL | VM_ALLOC_RETRY);
308 if (m->valid != VM_PAGE_BITS_ALL) {
309 rv = vm_pager_get_pages(upobj, &m, 1, 0);
310 if (rv != VM_PAGER_OK)
311 panic("vm_proc_swapin: cannot get upage");
312 }
313 ma[i] = m;
314 }
315 if (upobj->resident_page_count != UAREA_PAGES)
316 panic("vm_proc_swapin: lost pages from upobj");
317 vm_page_lock_queues();
318 TAILQ_FOREACH(m, &upobj->memq, listq) {
319 m->valid = VM_PAGE_BITS_ALL;
320 vm_page_wire(m);
321 vm_page_wakeup(m);
322 }
323 vm_page_unlock_queues();
324 up = (vm_offset_t)p->p_uarea;
325 pmap_qenter(up, ma, UAREA_PAGES);
326 }
327 #endif
328
329 /*
330 * Implement fork's actions on an address space.
331 * Here we arrange for the address space to be copied or referenced,
332 * allocate a user struct (pcb and kernel stack), then call the
333 * machine-dependent layer to fill those in and make the new process
334 * ready to run. The new process is set up so that it returns directly
335 * to user mode to avoid stack copying and relocation problems.
336 */
337 void
338 vm_forkproc(td, p2, td2, flags)
339 struct thread *td;
340 struct proc *p2;
341 struct thread *td2;
342 int flags;
343 {
344 struct proc *p1 = td->td_proc;
345 struct user *up;
346
347 GIANT_REQUIRED;
348
349 if ((flags & RFPROC) == 0) {
350 /*
351 * Divorce the memory, if it is shared, essentially
352 * this changes shared memory amongst threads, into
353 * COW locally.
354 */
355 if ((flags & RFMEM) == 0) {
356 if (p1->p_vmspace->vm_refcnt > 1) {
357 vmspace_unshare(p1);
358 }
359 }
360 cpu_fork(td, p2, td2, flags);
361 return;
362 }
363
364 if (flags & RFMEM) {
365 p2->p_vmspace = p1->p_vmspace;
366 p1->p_vmspace->vm_refcnt++;
367 }
368
369 while (vm_page_count_severe()) {
370 VM_WAIT;
371 }
372
373 if ((flags & RFMEM) == 0) {
374 p2->p_vmspace = vmspace_fork(p1->p_vmspace);
375
376 pmap_pinit2(vmspace_pmap(p2->p_vmspace));
377
378 if (p1->p_vmspace->vm_shm)
379 shmfork(p1, p2);
380 }
381
382 /* XXXKSE this is unsatisfactory but should be adequate */
383 up = p2->p_uarea;
384
385 /*
386 * p_stats currently points at fields in the user struct
387 * but not at &u, instead at p_addr. Copy parts of
388 * p_stats; zero the rest of p_stats (statistics).
389 *
390 * If procsig->ps_refcnt is 1 and p2->p_sigacts is NULL we dont' need
391 * to share sigacts, so we use the up->u_sigacts.
392 */
393 p2->p_stats = &up->u_stats;
394 if (p2->p_sigacts == NULL) {
395 if (p2->p_procsig->ps_refcnt != 1)
396 printf ("PID:%d NULL sigacts with refcnt not 1!\n",p2->p_pid);
397 p2->p_sigacts = &up->u_sigacts;
398 up->u_sigacts = *p1->p_sigacts;
399 }
400
401 bzero(&up->u_stats.pstat_startzero,
402 (unsigned) ((caddr_t) &up->u_stats.pstat_endzero -
403 (caddr_t) &up->u_stats.pstat_startzero));
404 bcopy(&p1->p_stats->pstat_startcopy, &up->u_stats.pstat_startcopy,
405 ((caddr_t) &up->u_stats.pstat_endcopy -
406 (caddr_t) &up->u_stats.pstat_startcopy));
407
408
409 /*
410 * cpu_fork will copy and update the pcb, set up the kernel stack,
411 * and make the child ready to run.
412 */
413 cpu_fork(td, p2, td2, flags);
414 }
415
416 /*
417 * Called after process has been wait(2)'ed apon and is being reaped.
418 * The idea is to reclaim resources that we could not reclaim while
419 * the process was still executing.
420 */
421 void
422 vm_waitproc(p)
423 struct proc *p;
424 {
425
426 GIANT_REQUIRED;
427 cpu_wait(p);
428 vmspace_exitfree(p); /* and clean-out the vmspace */
429 }
430
431 /*
432 * Set default limits for VM system.
433 * Called for proc 0, and then inherited by all others.
434 *
435 * XXX should probably act directly on proc0.
436 */
437 static void
438 vm_init_limits(udata)
439 void *udata;
440 {
441 struct proc *p = udata;
442 int rss_limit;
443
444 /*
445 * Set up the initial limits on process VM. Set the maximum resident
446 * set size to be half of (reasonably) available memory. Since this
447 * is a soft limit, it comes into effect only when the system is out
448 * of memory - half of main memory helps to favor smaller processes,
449 * and reduces thrashing of the object cache.
450 */
451 p->p_rlimit[RLIMIT_STACK].rlim_cur = dflssiz;
452 p->p_rlimit[RLIMIT_STACK].rlim_max = maxssiz;
453 p->p_rlimit[RLIMIT_DATA].rlim_cur = dfldsiz;
454 p->p_rlimit[RLIMIT_DATA].rlim_max = maxdsiz;
455 /* limit the limit to no less than 2MB */
456 rss_limit = max(cnt.v_free_count, 512);
457 p->p_rlimit[RLIMIT_RSS].rlim_cur = ptoa(rss_limit);
458 p->p_rlimit[RLIMIT_RSS].rlim_max = RLIM_INFINITY;
459 }
460
461 void
462 faultin(p)
463 struct proc *p;
464 {
465
466 GIANT_REQUIRED;
467 PROC_LOCK_ASSERT(p, MA_OWNED);
468 mtx_assert(&sched_lock, MA_OWNED);
469 #ifdef NO_SWAPPING
470 if ((p->p_sflag & PS_INMEM) == 0)
471 panic("faultin: proc swapped out with NO_SWAPPING!");
472 #else
473 if ((p->p_sflag & PS_INMEM) == 0) {
474 struct thread *td;
475
476 ++p->p_lock;
477 /*
478 * If another process is swapping in this process,
479 * just wait until it finishes.
480 */
481 if (p->p_sflag & PS_SWAPPINGIN) {
482 mtx_unlock_spin(&sched_lock);
483 msleep(&p->p_sflag, &p->p_mtx, PVM, "faultin", 0);
484 mtx_lock_spin(&sched_lock);
485 --p->p_lock;
486 return;
487 }
488
489 p->p_sflag |= PS_SWAPPINGIN;
490 mtx_unlock_spin(&sched_lock);
491 PROC_UNLOCK(p);
492
493 vm_proc_swapin(p);
494 FOREACH_THREAD_IN_PROC (p, td) {
495 pmap_swapin_thread(td);
496 TD_CLR_SWAPPED(td);
497 }
498
499 PROC_LOCK(p);
500 mtx_lock_spin(&sched_lock);
501 p->p_sflag &= ~PS_SWAPPINGIN;
502 p->p_sflag |= PS_INMEM;
503 FOREACH_THREAD_IN_PROC (p, td)
504 if (TD_CAN_RUN(td))
505 setrunnable(td);
506
507 wakeup(&p->p_sflag);
508
509 /* undo the effect of setting SLOCK above */
510 --p->p_lock;
511 }
512 #endif
513 }
514
515 /*
516 * This swapin algorithm attempts to swap-in processes only if there
517 * is enough space for them. Of course, if a process waits for a long
518 * time, it will be swapped in anyway.
519 *
520 * XXXKSE - process with the thread with highest priority counts..
521 *
522 * Giant is still held at this point, to be released in tsleep.
523 */
524 /* ARGSUSED*/
525 static void
526 scheduler(dummy)
527 void *dummy;
528 {
529 struct proc *p;
530 struct thread *td;
531 int pri;
532 struct proc *pp;
533 int ppri;
534
535 mtx_assert(&Giant, MA_OWNED | MA_NOTRECURSED);
536 /* GIANT_REQUIRED */
537
538 loop:
539 if (vm_page_count_min()) {
540 VM_WAIT;
541 goto loop;
542 }
543
544 pp = NULL;
545 ppri = INT_MIN;
546 sx_slock(&allproc_lock);
547 FOREACH_PROC_IN_SYSTEM(p) {
548 struct ksegrp *kg;
549 if (p->p_sflag & (PS_INMEM | PS_SWAPPING | PS_SWAPPINGIN)) {
550 continue;
551 }
552 mtx_lock_spin(&sched_lock);
553 FOREACH_THREAD_IN_PROC(p, td) {
554 /*
555 * An otherwise runnable thread of a process
556 * swapped out has only the TDI_SWAPPED bit set.
557 *
558 */
559 if (td->td_inhibitors == TDI_SWAPPED) {
560 kg = td->td_ksegrp;
561 pri = p->p_swtime + kg->kg_slptime;
562 if ((p->p_sflag & PS_SWAPINREQ) == 0) {
563 pri -= kg->kg_nice * 8;
564 }
565
566 /*
567 * if this ksegrp is higher priority
568 * and there is enough space, then select
569 * this process instead of the previous
570 * selection.
571 */
572 if (pri > ppri) {
573 pp = p;
574 ppri = pri;
575 }
576 }
577 }
578 mtx_unlock_spin(&sched_lock);
579 }
580 sx_sunlock(&allproc_lock);
581
582 /*
583 * Nothing to do, back to sleep.
584 */
585 if ((p = pp) == NULL) {
586 tsleep(&proc0, PVM, "sched", maxslp * hz / 2);
587 goto loop;
588 }
589 PROC_LOCK(p);
590 mtx_lock_spin(&sched_lock);
591
592 /*
593 * Another process may be bringing or may have already
594 * brought this process in while we traverse all threads.
595 * Or, this process may even be being swapped out again.
596 */
597 if (p->p_sflag & (PS_INMEM|PS_SWAPPING|PS_SWAPPINGIN)) {
598 mtx_unlock_spin(&sched_lock);
599 PROC_UNLOCK(p);
600 goto loop;
601 }
602
603 p->p_sflag &= ~PS_SWAPINREQ;
604
605 /*
606 * We would like to bring someone in. (only if there is space).
607 * [What checks the space? ]
608 */
609 faultin(p);
610 PROC_UNLOCK(p);
611 p->p_swtime = 0;
612 mtx_unlock_spin(&sched_lock);
613 goto loop;
614 }
615
616 #ifndef NO_SWAPPING
617
618 /*
619 * Swap_idle_threshold1 is the guaranteed swapped in time for a process
620 */
621 static int swap_idle_threshold1 = 2;
622 SYSCTL_INT(_vm, OID_AUTO, swap_idle_threshold1,
623 CTLFLAG_RW, &swap_idle_threshold1, 0, "");
624
625 /*
626 * Swap_idle_threshold2 is the time that a process can be idle before
627 * it will be swapped out, if idle swapping is enabled.
628 */
629 static int swap_idle_threshold2 = 10;
630 SYSCTL_INT(_vm, OID_AUTO, swap_idle_threshold2,
631 CTLFLAG_RW, &swap_idle_threshold2, 0, "");
632
633 /*
634 * Swapout is driven by the pageout daemon. Very simple, we find eligible
635 * procs and unwire their u-areas. We try to always "swap" at least one
636 * process in case we need the room for a swapin.
637 * If any procs have been sleeping/stopped for at least maxslp seconds,
638 * they are swapped. Else, we swap the longest-sleeping or stopped process,
639 * if any, otherwise the longest-resident process.
640 */
641 void
642 swapout_procs(action)
643 int action;
644 {
645 struct proc *p;
646 struct thread *td;
647 struct ksegrp *kg;
648 struct proc *outp, *outp2;
649 int outpri, outpri2;
650 int didswap = 0;
651
652 GIANT_REQUIRED;
653
654 outp = outp2 = NULL;
655 outpri = outpri2 = INT_MIN;
656 retry:
657 sx_slock(&allproc_lock);
658 FOREACH_PROC_IN_SYSTEM(p) {
659 struct vmspace *vm;
660 int minslptime = 100000;
661
662 /*
663 * Watch out for a process in
664 * creation. It may have no
665 * address space or lock yet.
666 */
667 mtx_lock_spin(&sched_lock);
668 if (p->p_state == PRS_NEW) {
669 mtx_unlock_spin(&sched_lock);
670 continue;
671 }
672 mtx_unlock_spin(&sched_lock);
673
674 /*
675 * An aio daemon switches its
676 * address space while running.
677 * Perform a quick check whether
678 * a process has P_SYSTEM.
679 */
680 PROC_LOCK(p);
681 if ((p->p_flag & P_SYSTEM) != 0) {
682 PROC_UNLOCK(p);
683 continue;
684 }
685
686 /*
687 * Do not swapout a process that
688 * is waiting for VM data
689 * structures as there is a possible
690 * deadlock. Test this first as
691 * this may block.
692 *
693 * Lock the map until swapout
694 * finishes, or a thread of this
695 * process may attempt to alter
696 * the map.
697 */
698 vm = p->p_vmspace;
699 KASSERT(vm != NULL,
700 ("swapout_procs: a process has no address space"));
701 ++vm->vm_refcnt;
702 PROC_UNLOCK(p);
703 if (!vm_map_trylock(&vm->vm_map))
704 goto nextproc1;
705
706 PROC_LOCK(p);
707 if (p->p_lock != 0 ||
708 (p->p_flag & (P_STOPPED_SINGLE|P_TRACED|P_SYSTEM|P_WEXIT)
709 ) != 0) {
710 goto nextproc2;
711 }
712 /*
713 * only aiod changes vmspace, however it will be
714 * skipped because of the if statement above checking
715 * for P_SYSTEM
716 */
717 mtx_lock_spin(&sched_lock);
718 if ((p->p_sflag & (PS_INMEM|PS_SWAPPING|PS_SWAPPINGIN)) != PS_INMEM)
719 goto nextproc;
720
721 switch (p->p_state) {
722 default:
723 /* Don't swap out processes in any sort
724 * of 'special' state. */
725 goto nextproc;
726
727 case PRS_NORMAL:
728 /*
729 * do not swapout a realtime process
730 * Check all the thread groups..
731 */
732 FOREACH_KSEGRP_IN_PROC(p, kg) {
733 if (PRI_IS_REALTIME(kg->kg_pri_class))
734 goto nextproc;
735
736 /*
737 * Guarantee swap_idle_threshold1
738 * time in memory.
739 */
740 if (kg->kg_slptime < swap_idle_threshold1)
741 goto nextproc;
742
743 /*
744 * Do not swapout a process if it is
745 * waiting on a critical event of some
746 * kind or there is a thread whose
747 * pageable memory may be accessed.
748 *
749 * This could be refined to support
750 * swapping out a thread.
751 */
752 FOREACH_THREAD_IN_GROUP(kg, td) {
753 if ((td->td_priority) < PSOCK ||
754 !thread_safetoswapout(td))
755 goto nextproc;
756 }
757 /*
758 * If the system is under memory stress,
759 * or if we are swapping
760 * idle processes >= swap_idle_threshold2,
761 * then swap the process out.
762 */
763 if (((action & VM_SWAP_NORMAL) == 0) &&
764 (((action & VM_SWAP_IDLE) == 0) ||
765 (kg->kg_slptime < swap_idle_threshold2)))
766 goto nextproc;
767
768 if (minslptime > kg->kg_slptime)
769 minslptime = kg->kg_slptime;
770 }
771
772 /*
773 * If the process has been asleep for awhile and had
774 * most of its pages taken away already, swap it out.
775 */
776 if ((action & VM_SWAP_NORMAL) ||
777 ((action & VM_SWAP_IDLE) &&
778 (minslptime > swap_idle_threshold2))) {
779 swapout(p);
780 didswap++;
781
782 /*
783 * swapout() unlocks a proc lock. This is
784 * ugly, but avoids superfluous lock.
785 */
786 mtx_unlock_spin(&sched_lock);
787 vm_map_unlock(&vm->vm_map);
788 vmspace_free(vm);
789 sx_sunlock(&allproc_lock);
790 goto retry;
791 }
792 }
793 nextproc:
794 mtx_unlock_spin(&sched_lock);
795 nextproc2:
796 PROC_UNLOCK(p);
797 vm_map_unlock(&vm->vm_map);
798 nextproc1:
799 vmspace_free(vm);
800 continue;
801 }
802 sx_sunlock(&allproc_lock);
803 /*
804 * If we swapped something out, and another process needed memory,
805 * then wakeup the sched process.
806 */
807 if (didswap)
808 wakeup(&proc0);
809 }
810
811 static void
812 swapout(p)
813 struct proc *p;
814 {
815 struct thread *td;
816
817 PROC_LOCK_ASSERT(p, MA_OWNED);
818 mtx_assert(&sched_lock, MA_OWNED | MA_NOTRECURSED);
819 #if defined(SWAP_DEBUG)
820 printf("swapping out %d\n", p->p_pid);
821 #endif
822
823 /*
824 * The states of this process and its threads may have changed
825 * by now. Assuming that there is only one pageout daemon thread,
826 * this process should still be in memory.
827 */
828 KASSERT((p->p_sflag & (PS_INMEM|PS_SWAPPING|PS_SWAPPINGIN)) == PS_INMEM,
829 ("swapout: lost a swapout race?"));
830
831 #if defined(INVARIANTS)
832 /*
833 * Make sure that all threads are safe to be swapped out.
834 *
835 * Alternatively, we could swap out only safe threads.
836 */
837 FOREACH_THREAD_IN_PROC(p, td) {
838 KASSERT(thread_safetoswapout(td),
839 ("swapout: there is a thread not safe for swapout"));
840 }
841 #endif /* INVARIANTS */
842
843 ++p->p_stats->p_ru.ru_nswap;
844 /*
845 * remember the process resident count
846 */
847 p->p_vmspace->vm_swrss = vmspace_resident_count(p->p_vmspace);
848
849 PROC_UNLOCK(p);
850 p->p_sflag &= ~PS_INMEM;
851 p->p_sflag |= PS_SWAPPING;
852 mtx_unlock_spin(&sched_lock);
853
854 vm_proc_swapout(p);
855 FOREACH_THREAD_IN_PROC(p, td) {
856 pmap_swapout_thread(td);
857 TD_SET_SWAPPED(td);
858 }
859 mtx_lock_spin(&sched_lock);
860 p->p_sflag &= ~PS_SWAPPING;
861 p->p_swtime = 0;
862 }
863 #endif /* !NO_SWAPPING */
Cache object: 940a3ff0bedcacdfc919ce1d1cc7d0cb
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