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
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29 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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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
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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
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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 1.24 2004/06/20 22:29:10 hmp 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 (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 (void *);
110 SYSINIT(scheduler, SI_SUB_RUN_SCHEDULER, SI_ORDER_FIRST, scheduler, NULL)
113 static void swapout (struct proc *);
116 kernacc(caddr_t addr, int len, int rw)
119 vm_offset_t saddr, eaddr;
122 KASSERT((rw & (~VM_PROT_ALL)) == 0,
123 ("illegal ``rw'' argument to kernacc (%x)\n", rw));
125 saddr = trunc_page((vm_offset_t)addr);
126 eaddr = round_page((vm_offset_t)addr + len);
127 vm_map_lock_read(kernel_map);
128 rv = vm_map_check_protection(kernel_map, saddr, eaddr, prot);
129 vm_map_unlock_read(kernel_map);
134 useracc(caddr_t addr, int len, int rw)
139 vm_map_entry_t save_hint;
141 KASSERT((rw & (~VM_PROT_ALL)) == 0,
142 ("illegal ``rw'' argument to useracc (%x)\n", rw));
145 * XXX - check separately to disallow access to user area and user
146 * page tables - they are in the map.
148 * XXX - VM_MAXUSER_ADDRESS is an end address, not a max. It was once
149 * only used (as an end address) in trap.c. Use it as an end address
150 * here too. This bogusness has spread. I just fixed where it was
151 * used as a max in vm_mmap.c.
153 if ((vm_offset_t) addr + len > /* XXX */ VM_MAXUSER_ADDRESS
154 || (vm_offset_t) addr + len < (vm_offset_t) addr) {
157 map = &curproc->p_vmspace->vm_map;
158 vm_map_lock_read(map);
160 * We save the map hint, and restore it. Useracc appears to distort
161 * the map hint unnecessarily.
163 save_hint = map->hint;
164 rv = vm_map_check_protection(map,
165 trunc_page((vm_offset_t)addr), round_page((vm_offset_t)addr + len), prot);
166 map->hint = save_hint;
167 vm_map_unlock_read(map);
173 vslock(caddr_t addr, u_int len)
175 vm_map_wire(&curproc->p_vmspace->vm_map, trunc_page((vm_offset_t)addr),
176 round_page((vm_offset_t)addr + len), 0);
180 vsunlock(caddr_t addr, u_int len)
182 vm_map_wire(&curproc->p_vmspace->vm_map, trunc_page((vm_offset_t)addr),
183 round_page((vm_offset_t)addr + len), KM_PAGEABLE);
187 * Implement fork's actions on an address space.
188 * Here we arrange for the address space to be copied or referenced,
189 * allocate a user struct (pcb and kernel stack), then call the
190 * machine-dependent layer to fill those in and make the new process
191 * ready to run. The new process is set up so that it returns directly
192 * to user mode to avoid stack copying and relocation problems.
195 vm_fork(struct proc *p1, struct proc *p2, int flags)
200 if ((flags & RFPROC) == 0) {
202 * Divorce the memory, if it is shared, essentially
203 * this changes shared memory amongst threads, into
206 if ((flags & RFMEM) == 0) {
207 if (p1->p_vmspace->vm_refcnt > 1) {
211 cpu_fork(p1, p2, flags);
216 p2->p_vmspace = p1->p_vmspace;
217 p1->p_vmspace->vm_refcnt++;
220 while (vm_page_count_severe()) {
224 if ((flags & RFMEM) == 0) {
225 p2->p_vmspace = vmspace_fork(p1->p_vmspace);
227 pmap_pinit2(vmspace_pmap(p2->p_vmspace));
229 if (p1->p_vmspace->vm_shm)
233 td2 = lwkt_alloc_thread(NULL, -1);
234 pmap_init_proc(p2, td2);
235 lwkt_setpri(td2, TDPRI_KERN_USER);
236 lwkt_set_comm(td2, "%s", p1->p_comm);
241 * p_stats currently points at fields in the user struct
242 * but not at &u, instead at p_addr. Copy parts of
243 * p_stats; zero the rest of p_stats (statistics).
245 * If procsig->ps_refcnt is 1 and p2->p_sigacts is NULL we dont' need
246 * to share sigacts, so we use the up->u_sigacts.
248 p2->p_stats = &up->u_stats;
249 if (p2->p_sigacts == NULL) {
250 if (p2->p_procsig->ps_refcnt != 1)
251 printf ("PID:%d NULL sigacts with refcnt not 1!\n",p2->p_pid);
252 p2->p_sigacts = &up->u_sigacts;
253 up->u_sigacts = *p1->p_sigacts;
256 bzero(&up->u_stats, sizeof(struct pstats));
257 bcopy(&p1->p_stats->p_prof, &up->u_stats.p_prof,
258 sizeof(struct uprof));
259 bcopy(&p1->p_thread->td_start, &p2->p_thread->td_start,
260 sizeof(struct timeval));
264 * cpu_fork will copy and update the pcb, set up the kernel stack,
265 * and make the child ready to run.
267 cpu_fork(p1, p2, flags);
271 * Called after process has been wait(2)'ed apon and is being reaped.
272 * The idea is to reclaim resources that we could not reclaim while
273 * the process was still executing.
276 vm_waitproc(struct proc *p)
279 vmspace_exitfree(p); /* and clean-out the vmspace */
283 * Set default limits for VM system.
284 * Called for proc 0, and then inherited by all others.
286 * XXX should probably act directly on proc0.
289 vm_init_limits(void *udata)
291 struct proc *p = udata;
295 * Set up the initial limits on process VM. Set the maximum resident
296 * set size to be half of (reasonably) available memory. Since this
297 * is a soft limit, it comes into effect only when the system is out
298 * of memory - half of main memory helps to favor smaller processes,
299 * and reduces thrashing of the object cache.
301 p->p_rlimit[RLIMIT_STACK].rlim_cur = dflssiz;
302 p->p_rlimit[RLIMIT_STACK].rlim_max = maxssiz;
303 p->p_rlimit[RLIMIT_DATA].rlim_cur = dfldsiz;
304 p->p_rlimit[RLIMIT_DATA].rlim_max = maxdsiz;
305 /* limit the limit to no less than 2MB */
306 rss_limit = max(vmstats.v_free_count, 512);
307 p->p_rlimit[RLIMIT_RSS].rlim_cur = ptoa(rss_limit);
308 p->p_rlimit[RLIMIT_RSS].rlim_max = RLIM_INFINITY;
312 faultin(struct proc *p)
316 if ((p->p_flag & P_INMEM) == 0) {
324 if (p->p_stat == SRUN)
327 p->p_flag |= P_INMEM;
329 /* undo the effect of setting SLOCK above */
337 * Kernel initialization eventually falls through to this function,
338 * which is process 0.
340 * This swapin algorithm attempts to swap-in processes only if there
341 * is enough space for them. Of course, if a process waits for a long
342 * time, it will be swapped in anyway.
346 scheduler(void *dummy)
353 KKASSERT(!IN_CRITICAL_SECT(curthread));
355 if (vm_page_count_min()) {
362 for (p = allproc.lh_first; p != 0; p = p->p_list.le_next) {
363 if (p->p_stat == SRUN &&
364 (p->p_flag & (P_INMEM | P_SWAPPING)) == 0) {
366 pri = p->p_swtime + p->p_slptime;
367 if ((p->p_flag & P_SWAPINREQ) == 0) {
368 pri -= p->p_nice * 8;
372 * if this process is higher priority and there is
373 * enough space, then select this process instead of
374 * the previous selection.
384 * Nothing to do, back to sleep.
386 if ((p = pp) == NULL) {
387 tsleep(&proc0, 0, "sched", 0);
390 p->p_flag &= ~P_SWAPINREQ;
393 * We would like to bring someone in. (only if there is space).
402 #define swappable(p) \
403 (((p)->p_lock == 0) && \
404 ((p)->p_flag & (P_TRACED|P_SYSTEM|P_INMEM|P_WEXIT|P_SWAPPING)) == P_INMEM)
408 * Swap_idle_threshold1 is the guaranteed swapped in time for a process
410 static int swap_idle_threshold1 = 2;
411 SYSCTL_INT(_vm, OID_AUTO, swap_idle_threshold1,
412 CTLFLAG_RW, &swap_idle_threshold1, 0, "");
415 * Swap_idle_threshold2 is the time that a process can be idle before
416 * it will be swapped out, if idle swapping is enabled.
418 static int swap_idle_threshold2 = 10;
419 SYSCTL_INT(_vm, OID_AUTO, swap_idle_threshold2,
420 CTLFLAG_RW, &swap_idle_threshold2, 0, "");
423 * Swapout is driven by the pageout daemon. Very simple, we find eligible
424 * procs and unwire their u-areas. We try to always "swap" at least one
425 * process in case we need the room for a swapin.
426 * If any procs have been sleeping/stopped for at least maxslp seconds,
427 * they are swapped. Else, we swap the longest-sleeping or stopped process,
428 * if any, otherwise the longest-resident process.
431 swapout_procs(int action)
434 struct proc *outp, *outp2;
439 outpri = outpri2 = INT_MIN;
441 for (p = allproc.lh_first; p != 0; p = p->p_list.le_next) {
455 * do not swapout a realtime process
457 if (RTP_PRIO_IS_REALTIME(p->p_rtprio.type))
461 * YYY do not swapout a proc waiting on a critical
464 * Guarentee swap_idle_threshold time in memory
466 if (p->p_slptime < swap_idle_threshold1)
470 * If the system is under memory stress, or if we
471 * are swapping idle processes >= swap_idle_threshold2,
472 * then swap the process out.
474 if (((action & VM_SWAP_NORMAL) == 0) &&
475 (((action & VM_SWAP_IDLE) == 0) ||
476 (p->p_slptime < swap_idle_threshold2)))
481 * do not swapout a process that is waiting for VM
482 * data structures there is a possible deadlock.
484 if (lockmgr(&vm->vm_map.lock,
485 LK_EXCLUSIVE | LK_NOWAIT,
490 vm_map_unlock(&vm->vm_map);
492 * If the process has been asleep for awhile and had
493 * most of its pages taken away already, swap it out.
495 if ((action & VM_SWAP_NORMAL) ||
496 ((action & VM_SWAP_IDLE) &&
497 (p->p_slptime > swap_idle_threshold2))) {
505 * cleanup our reference
511 * If we swapped something out, and another process needed memory,
512 * then wakeup the sched process.
519 swapout(struct proc *p)
522 #if defined(SWAP_DEBUG)
523 printf("swapping out %d\n", p->p_pid);
525 ++p->p_stats->p_ru.ru_nswap;
527 * remember the process resident count
529 p->p_vmspace->vm_swrss = vmspace_resident_count(p->p_vmspace);
532 p->p_flag &= ~P_INMEM;
533 p->p_flag |= P_SWAPPING;
534 if (p->p_flag & P_ONRUNQ)
538 pmap_swapout_proc(p);
540 p->p_flag &= ~P_SWAPPING;
543 #endif /* !NO_SWAPPING */