2 * Copyright (c) 1991, 1993
3 * The Regents of the University of California. All rights reserved.
5 * This code is derived from software contributed to Berkeley by
6 * The Mach Operating System project at Carnegie-Mellon University.
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted provided that the following conditions
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.
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
36 * from: @(#)vm_glue.c 8.6 (Berkeley) 1/5/94
39 * Copyright (c) 1987, 1990 Carnegie-Mellon University.
40 * All rights reserved.
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
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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.
52 * Carnegie Mellon requests users of this software to return to
54 * Software Distribution Coordinator or Software.Distribution@CS.CMU.EDU
55 * School of Computer Science
56 * Carnegie Mellon University
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59 * any improvements or extensions that they make and grant Carnegie the
60 * rights to redistribute these changes.
62 * $FreeBSD: src/sys/vm/vm_glue.c,v 1.94.2.4 2003/01/13 22:51:17 dillon Exp $
63 * $DragonFly: src/sys/vm/vm_glue.c,v 1.13 2003/07/19 21:14:53 dillon Exp $
68 #include <sys/param.h>
69 #include <sys/systm.h>
71 #include <sys/resourcevar.h>
74 #include <sys/vmmeter.h>
75 #include <sys/sysctl.h>
77 #include <sys/kernel.h>
78 #include <sys/unistd.h>
80 #include <machine/limits.h>
83 #include <vm/vm_param.h>
86 #include <vm/vm_map.h>
87 #include <vm/vm_page.h>
88 #include <vm/vm_pageout.h>
89 #include <vm/vm_kern.h>
90 #include <vm/vm_extern.h>
93 #include <vm/vm_page2.h>
96 * System initialization
98 * Note: proc0 from proc.h
101 static void vm_init_limits __P((void *));
102 SYSINIT(vm_limits, SI_SUB_VM_CONF, SI_ORDER_FIRST, vm_init_limits, &proc0)
105 * THIS MUST BE THE LAST INITIALIZATION ITEM!!!
107 * Note: run scheduling should be divorced from the vm system.
109 static void scheduler __P((void *));
110 SYSINIT(scheduler, SI_SUB_RUN_SCHEDULER, SI_ORDER_FIRST, scheduler, NULL)
113 static void swapout __P((struct proc *));
116 kernacc(addr, len, rw)
121 vm_offset_t saddr, eaddr;
124 KASSERT((rw & (~VM_PROT_ALL)) == 0,
125 ("illegal ``rw'' argument to kernacc (%x)\n", rw));
127 saddr = trunc_page((vm_offset_t)addr);
128 eaddr = round_page((vm_offset_t)addr + len);
129 vm_map_lock_read(kernel_map);
130 rv = vm_map_check_protection(kernel_map, saddr, eaddr, prot);
131 vm_map_unlock_read(kernel_map);
136 useracc(addr, len, rw)
143 vm_map_entry_t save_hint;
145 KASSERT((rw & (~VM_PROT_ALL)) == 0,
146 ("illegal ``rw'' argument to useracc (%x)\n", rw));
149 * XXX - check separately to disallow access to user area and user
150 * page tables - they are in the map.
152 * XXX - VM_MAXUSER_ADDRESS is an end address, not a max. It was once
153 * only used (as an end address) in trap.c. Use it as an end address
154 * here too. This bogusness has spread. I just fixed where it was
155 * used as a max in vm_mmap.c.
157 if ((vm_offset_t) addr + len > /* XXX */ VM_MAXUSER_ADDRESS
158 || (vm_offset_t) addr + len < (vm_offset_t) addr) {
161 map = &curproc->p_vmspace->vm_map;
162 vm_map_lock_read(map);
164 * We save the map hint, and restore it. Useracc appears to distort
165 * the map hint unnecessarily.
167 save_hint = map->hint;
168 rv = vm_map_check_protection(map,
169 trunc_page((vm_offset_t)addr), round_page((vm_offset_t)addr + len), prot);
170 map->hint = save_hint;
171 vm_map_unlock_read(map);
181 vm_map_pageable(&curproc->p_vmspace->vm_map, trunc_page((vm_offset_t)addr),
182 round_page((vm_offset_t)addr + len), FALSE);
190 vm_map_pageable(&curproc->p_vmspace->vm_map, trunc_page((vm_offset_t)addr),
191 round_page((vm_offset_t)addr + len), TRUE);
195 * Implement fork's actions on an address space.
196 * Here we arrange for the address space to be copied or referenced,
197 * allocate a user struct (pcb and kernel stack), then call the
198 * machine-dependent layer to fill those in and make the new process
199 * ready to run. The new process is set up so that it returns directly
200 * to user mode to avoid stack copying and relocation problems.
203 vm_fork(p1, p2, flags)
204 register struct proc *p1, *p2;
207 register struct user *up;
210 if ((flags & RFPROC) == 0) {
212 * Divorce the memory, if it is shared, essentially
213 * this changes shared memory amongst threads, into
216 if ((flags & RFMEM) == 0) {
217 if (p1->p_vmspace->vm_refcnt > 1) {
221 cpu_fork(p1, p2, flags);
226 p2->p_vmspace = p1->p_vmspace;
227 p1->p_vmspace->vm_refcnt++;
230 while (vm_page_count_severe()) {
234 if ((flags & RFMEM) == 0) {
235 p2->p_vmspace = vmspace_fork(p1->p_vmspace);
237 pmap_pinit2(vmspace_pmap(p2->p_vmspace));
239 if (p1->p_vmspace->vm_shm)
243 td2 = lwkt_alloc_thread(NULL);
244 pmap_init_proc(p2, td2);
245 lwkt_setpri(td2, TDPRI_KERN_USER);
246 lwkt_set_comm(td2, "%s", p1->p_comm);
251 * p_stats currently points at fields in the user struct
252 * but not at &u, instead at p_addr. Copy parts of
253 * p_stats; zero the rest of p_stats (statistics).
255 * If procsig->ps_refcnt is 1 and p2->p_sigacts is NULL we dont' need
256 * to share sigacts, so we use the up->u_sigacts.
258 p2->p_stats = &up->u_stats;
259 if (p2->p_sigacts == NULL) {
260 if (p2->p_procsig->ps_refcnt != 1)
261 printf ("PID:%d NULL sigacts with refcnt not 1!\n",p2->p_pid);
262 p2->p_sigacts = &up->u_sigacts;
263 up->u_sigacts = *p1->p_sigacts;
266 bzero(&up->u_stats.pstat_startzero,
267 (unsigned) ((caddr_t) &up->u_stats.pstat_endzero -
268 (caddr_t) &up->u_stats.pstat_startzero));
269 bcopy(&p1->p_stats->pstat_startcopy, &up->u_stats.pstat_startcopy,
270 ((caddr_t) &up->u_stats.pstat_endcopy -
271 (caddr_t) &up->u_stats.pstat_startcopy));
275 * cpu_fork will copy and update the pcb, set up the kernel stack,
276 * and make the child ready to run.
278 cpu_fork(p1, p2, flags);
282 * Called after process has been wait(2)'ed apon and is being reaped.
283 * The idea is to reclaim resources that we could not reclaim while
284 * the process was still executing.
287 vm_waitproc(struct proc *p)
290 vmspace_exitfree(p); /* and clean-out the vmspace */
294 * Set default limits for VM system.
295 * Called for proc 0, and then inherited by all others.
297 * XXX should probably act directly on proc0.
300 vm_init_limits(udata)
303 register struct proc *p = udata;
307 * Set up the initial limits on process VM. Set the maximum resident
308 * set size to be half of (reasonably) available memory. Since this
309 * is a soft limit, it comes into effect only when the system is out
310 * of memory - half of main memory helps to favor smaller processes,
311 * and reduces thrashing of the object cache.
313 p->p_rlimit[RLIMIT_STACK].rlim_cur = dflssiz;
314 p->p_rlimit[RLIMIT_STACK].rlim_max = maxssiz;
315 p->p_rlimit[RLIMIT_DATA].rlim_cur = dfldsiz;
316 p->p_rlimit[RLIMIT_DATA].rlim_max = maxdsiz;
317 /* limit the limit to no less than 2MB */
318 rss_limit = max(vmstats.v_free_count, 512);
319 p->p_rlimit[RLIMIT_RSS].rlim_cur = ptoa(rss_limit);
320 p->p_rlimit[RLIMIT_RSS].rlim_max = RLIM_INFINITY;
329 if ((p->p_flag & P_INMEM) == 0) {
337 if (p->p_stat == SRUN)
340 p->p_flag |= P_INMEM;
342 /* undo the effect of setting SLOCK above */
350 * This swapin algorithm attempts to swap-in processes only if there
351 * is enough space for them. Of course, if a process waits for a long
352 * time, it will be swapped in anyway.
359 register struct proc *p;
365 if (vm_page_count_min()) {
372 for (p = allproc.lh_first; p != 0; p = p->p_list.le_next) {
373 if (p->p_stat == SRUN &&
374 (p->p_flag & (P_INMEM | P_SWAPPING)) == 0) {
376 pri = p->p_swtime + p->p_slptime;
377 if ((p->p_flag & P_SWAPINREQ) == 0) {
378 pri -= p->p_nice * 8;
382 * if this process is higher priority and there is
383 * enough space, then select this process instead of
384 * the previous selection.
394 * Nothing to do, back to sleep.
396 if ((p = pp) == NULL) {
397 tsleep(&proc0, 0, "sched", 0);
400 p->p_flag &= ~P_SWAPINREQ;
403 * We would like to bring someone in. (only if there is space).
412 #define swappable(p) \
413 (((p)->p_lock == 0) && \
414 ((p)->p_flag & (P_TRACED|P_SYSTEM|P_INMEM|P_WEXIT|P_SWAPPING)) == P_INMEM)
418 * Swap_idle_threshold1 is the guaranteed swapped in time for a process
420 static int swap_idle_threshold1 = 2;
421 SYSCTL_INT(_vm, OID_AUTO, swap_idle_threshold1,
422 CTLFLAG_RW, &swap_idle_threshold1, 0, "");
425 * Swap_idle_threshold2 is the time that a process can be idle before
426 * it will be swapped out, if idle swapping is enabled.
428 static int swap_idle_threshold2 = 10;
429 SYSCTL_INT(_vm, OID_AUTO, swap_idle_threshold2,
430 CTLFLAG_RW, &swap_idle_threshold2, 0, "");
433 * Swapout is driven by the pageout daemon. Very simple, we find eligible
434 * procs and unwire their u-areas. We try to always "swap" at least one
435 * process in case we need the room for a swapin.
436 * If any procs have been sleeping/stopped for at least maxslp seconds,
437 * they are swapped. Else, we swap the longest-sleeping or stopped process,
438 * if any, otherwise the longest-resident process.
441 swapout_procs(action)
444 register struct proc *p;
445 struct proc *outp, *outp2;
450 outpri = outpri2 = INT_MIN;
452 for (p = allproc.lh_first; p != 0; p = p->p_list.le_next) {
466 * do not swapout a realtime process
468 if (RTP_PRIO_IS_REALTIME(p->p_rtprio.type))
472 * YYY do not swapout a proc waiting on a critical
475 * Guarentee swap_idle_threshold time in memory
477 if (p->p_slptime < swap_idle_threshold1)
481 * If the system is under memory stress, or if we
482 * are swapping idle processes >= swap_idle_threshold2,
483 * then swap the process out.
485 if (((action & VM_SWAP_NORMAL) == 0) &&
486 (((action & VM_SWAP_IDLE) == 0) ||
487 (p->p_slptime < swap_idle_threshold2)))
492 * do not swapout a process that is waiting for VM
493 * data structures there is a possible deadlock.
495 if (lockmgr(&vm->vm_map.lock,
496 LK_EXCLUSIVE | LK_NOWAIT,
497 (void *)0, curthread)) {
501 vm_map_unlock(&vm->vm_map);
503 * If the process has been asleep for awhile and had
504 * most of its pages taken away already, swap it out.
506 if ((action & VM_SWAP_NORMAL) ||
507 ((action & VM_SWAP_IDLE) &&
508 (p->p_slptime > swap_idle_threshold2))) {
516 * cleanup our reference
522 * If we swapped something out, and another process needed memory,
523 * then wakeup the sched process.
531 register struct proc *p;
534 #if defined(SWAP_DEBUG)
535 printf("swapping out %d\n", p->p_pid);
537 ++p->p_stats->p_ru.ru_nswap;
539 * remember the process resident count
541 p->p_vmspace->vm_swrss = vmspace_resident_count(p->p_vmspace);
544 p->p_flag &= ~P_INMEM;
545 p->p_flag |= P_SWAPPING;
546 if (p->p_flag & P_ONRUNQ)
550 pmap_swapout_proc(p);
552 p->p_flag &= ~P_SWAPPING;
555 #endif /* !NO_SWAPPING */