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[dragonfly.git] / sys / vm / vm_glue.c
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1 /*
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
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.
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.
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
46 * thereof, and that both notices appear in supporting documentation.
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
57 * Pittsburgh PA 15213-3890
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 1.56 2008/07/01 02:02:56 dillon Exp $
66 #include "opt_vm.h"
68 #include <sys/param.h>
69 #include <sys/systm.h>
70 #include <sys/proc.h>
71 #include <sys/resourcevar.h>
72 #include <sys/buf.h>
73 #include <sys/shm.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>
82 #include <vm/vm.h>
83 #include <vm/vm_param.h>
84 #include <sys/lock.h>
85 #include <vm/pmap.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>
92 #include <sys/user.h>
93 #include <vm/vm_page2.h>
94 #include <sys/thread2.h>
95 #include <sys/sysref2.h>
98 * THIS MUST BE THE LAST INITIALIZATION ITEM!!!
100 * Note: run scheduling should be divorced from the vm system.
102 static void scheduler (void *);
103 SYSINIT(scheduler, SI_SUB_RUN_SCHEDULER, SI_ORDER_FIRST, scheduler, NULL)
105 #ifdef INVARIANTS
107 static int swap_debug = 0;
108 SYSCTL_INT(_vm, OID_AUTO, swap_debug,
109 CTLFLAG_RW, &swap_debug, 0, "");
111 #endif
113 static int scheduler_notify;
115 static void swapout (struct proc *);
118 kernacc(c_caddr_t addr, int len, int rw)
120 boolean_t rv;
121 vm_offset_t saddr, eaddr;
122 vm_prot_t prot;
124 KASSERT((rw & (~VM_PROT_ALL)) == 0,
125 ("illegal ``rw'' argument to kernacc (%x)\n", rw));
128 * The globaldata space is not part of the kernel_map proper,
129 * check access separately.
131 if (is_globaldata_space((vm_offset_t)addr, (vm_offset_t)(addr + len)))
132 return (TRUE);
135 * Nominal kernel memory access - check access via kernel_map.
137 if ((vm_offset_t)addr + len > kernel_map.max_offset ||
138 (vm_offset_t)addr + len < (vm_offset_t)addr) {
139 return (FALSE);
141 prot = rw;
142 saddr = trunc_page((vm_offset_t)addr);
143 eaddr = round_page((vm_offset_t)addr + len);
144 vm_map_lock_read(&kernel_map);
145 rv = vm_map_check_protection(&kernel_map, saddr, eaddr, prot);
146 vm_map_unlock_read(&kernel_map);
147 return (rv == TRUE);
151 useracc(c_caddr_t addr, int len, int rw)
153 boolean_t rv;
154 vm_prot_t prot;
155 vm_map_t map;
156 vm_map_entry_t save_hint;
158 KASSERT((rw & (~VM_PROT_ALL)) == 0,
159 ("illegal ``rw'' argument to useracc (%x)\n", rw));
160 prot = rw;
162 * XXX - check separately to disallow access to user area and user
163 * page tables - they are in the map.
165 * XXX - VM_MAX_USER_ADDRESS is an end address, not a max. It was once
166 * only used (as an end address) in trap.c. Use it as an end address
167 * here too. This bogusness has spread. I just fixed where it was
168 * used as a max in vm_mmap.c.
170 if ((vm_offset_t) addr + len > /* XXX */ VM_MAX_USER_ADDRESS
171 || (vm_offset_t) addr + len < (vm_offset_t) addr) {
172 return (FALSE);
174 map = &curproc->p_vmspace->vm_map;
175 vm_map_lock_read(map);
177 * We save the map hint, and restore it. Useracc appears to distort
178 * the map hint unnecessarily.
180 save_hint = map->hint;
181 rv = vm_map_check_protection(map,
182 trunc_page((vm_offset_t)addr), round_page((vm_offset_t)addr + len), prot);
183 map->hint = save_hint;
184 vm_map_unlock_read(map);
186 return (rv == TRUE);
189 void
190 vslock(caddr_t addr, u_int len)
192 if (len) {
193 vm_map_wire(&curproc->p_vmspace->vm_map,
194 trunc_page((vm_offset_t)addr),
195 round_page((vm_offset_t)addr + len), 0);
199 void
200 vsunlock(caddr_t addr, u_int len)
202 if (len) {
203 vm_map_wire(&curproc->p_vmspace->vm_map,
204 trunc_page((vm_offset_t)addr),
205 round_page((vm_offset_t)addr + len),
206 KM_PAGEABLE);
211 * Implement fork's actions on an address space.
212 * Here we arrange for the address space to be copied or referenced,
213 * allocate a user struct (pcb and kernel stack), then call the
214 * machine-dependent layer to fill those in and make the new process
215 * ready to run. The new process is set up so that it returns directly
216 * to user mode to avoid stack copying and relocation problems.
218 void
219 vm_fork(struct proc *p1, struct proc *p2, int flags)
221 if ((flags & RFPROC) == 0) {
223 * Divorce the memory, if it is shared, essentially
224 * this changes shared memory amongst threads, into
225 * COW locally.
227 if ((flags & RFMEM) == 0) {
228 if (p1->p_vmspace->vm_sysref.refcnt > 1) {
229 vmspace_unshare(p1);
232 cpu_fork(ONLY_LWP_IN_PROC(p1), NULL, flags);
233 return;
236 if (flags & RFMEM) {
237 p2->p_vmspace = p1->p_vmspace;
238 sysref_get(&p1->p_vmspace->vm_sysref);
241 while (vm_page_count_severe()) {
242 vm_wait(0);
245 if ((flags & RFMEM) == 0) {
246 p2->p_vmspace = vmspace_fork(p1->p_vmspace);
248 pmap_pinit2(vmspace_pmap(p2->p_vmspace));
250 if (p1->p_vmspace->vm_shm)
251 shmfork(p1, p2);
254 pmap_init_proc(p2);
258 * Called after process has been wait(2)'ed apon and is being reaped.
259 * The idea is to reclaim resources that we could not reclaim while
260 * the process was still executing.
262 void
263 vm_waitproc(struct proc *p)
265 cpu_proc_wait(p);
266 vmspace_exitfree(p); /* and clean-out the vmspace */
270 * Set default limits for VM system. Call during proc0's initialization.
272 void
273 vm_init_limits(struct proc *p)
275 int rss_limit;
278 * Set up the initial limits on process VM. Set the maximum resident
279 * set size to be half of (reasonably) available memory. Since this
280 * is a soft limit, it comes into effect only when the system is out
281 * of memory - half of main memory helps to favor smaller processes,
282 * and reduces thrashing of the object cache.
284 p->p_rlimit[RLIMIT_STACK].rlim_cur = dflssiz;
285 p->p_rlimit[RLIMIT_STACK].rlim_max = maxssiz;
286 p->p_rlimit[RLIMIT_DATA].rlim_cur = dfldsiz;
287 p->p_rlimit[RLIMIT_DATA].rlim_max = maxdsiz;
288 /* limit the limit to no less than 2MB */
289 rss_limit = max(vmstats.v_free_count, 512);
290 p->p_rlimit[RLIMIT_RSS].rlim_cur = ptoa(rss_limit);
291 p->p_rlimit[RLIMIT_RSS].rlim_max = RLIM_INFINITY;
295 * Faultin the specified process. Note that the process can be in any
296 * state. Just clear P_SWAPPEDOUT and call wakeup in case the process is
297 * sleeping.
299 void
300 faultin(struct proc *p)
302 if (p->p_flag & P_SWAPPEDOUT) {
304 * The process is waiting in the kernel to return to user
305 * mode but cannot until P_SWAPPEDOUT gets cleared.
307 crit_enter();
308 p->p_flag &= ~(P_SWAPPEDOUT | P_SWAPWAIT);
309 #ifdef INVARIANTS
310 if (swap_debug)
311 kprintf("swapping in %d (%s)\n", p->p_pid, p->p_comm);
312 #endif
313 wakeup(p);
315 crit_exit();
320 * Kernel initialization eventually falls through to this function,
321 * which is process 0.
323 * This swapin algorithm attempts to swap-in processes only if there
324 * is enough space for them. Of course, if a process waits for a long
325 * time, it will be swapped in anyway.
328 struct scheduler_info {
329 struct proc *pp;
330 int ppri;
333 static int scheduler_callback(struct proc *p, void *data);
335 static void
336 scheduler(void *dummy)
338 struct scheduler_info info;
339 struct proc *p;
341 KKASSERT(!IN_CRITICAL_SECT(curthread));
342 loop:
343 scheduler_notify = 0;
345 * Don't try to swap anything in if we are low on memory.
347 if (vm_page_count_severe()) {
348 vm_wait(0);
349 goto loop;
353 * Look for a good candidate to wake up
355 info.pp = NULL;
356 info.ppri = INT_MIN;
357 allproc_scan(scheduler_callback, &info);
360 * Nothing to do, back to sleep for at least 1/10 of a second. If
361 * we are woken up, immediately process the next request. If
362 * multiple requests have built up the first is processed
363 * immediately and the rest are staggered.
365 if ((p = info.pp) == NULL) {
366 tsleep(&proc0, 0, "nowork", hz / 10);
367 if (scheduler_notify == 0)
368 tsleep(&scheduler_notify, 0, "nowork", 0);
369 goto loop;
373 * Fault the selected process in, then wait for a short period of
374 * time and loop up.
376 * XXX we need a heuristic to get a measure of system stress and
377 * then adjust our stagger wakeup delay accordingly.
379 faultin(p);
380 p->p_swtime = 0;
381 PRELE(p);
382 tsleep(&proc0, 0, "swapin", hz / 10);
383 goto loop;
386 static int
387 scheduler_callback(struct proc *p, void *data)
389 struct scheduler_info *info = data;
390 struct lwp *lp;
391 segsz_t pgs;
392 int pri;
394 if (p->p_flag & P_SWAPWAIT) {
395 pri = 0;
396 FOREACH_LWP_IN_PROC(lp, p) {
397 /* XXX lwp might need a different metric */
398 pri += lp->lwp_slptime;
400 pri += p->p_swtime - p->p_nice * 8;
403 * The more pages paged out while we were swapped,
404 * the more work we have to do to get up and running
405 * again and the lower our wakeup priority.
407 * Each second of sleep time is worth ~1MB
409 pgs = vmspace_resident_count(p->p_vmspace);
410 if (pgs < p->p_vmspace->vm_swrss) {
411 pri -= (p->p_vmspace->vm_swrss - pgs) /
412 (1024 * 1024 / PAGE_SIZE);
416 * If this process is higher priority and there is
417 * enough space, then select this process instead of
418 * the previous selection.
420 if (pri > info->ppri) {
421 if (info->pp)
422 PRELE(info->pp);
423 PHOLD(p);
424 info->pp = p;
425 info->ppri = pri;
428 return(0);
431 void
432 swapin_request(void)
434 if (scheduler_notify == 0) {
435 scheduler_notify = 1;
436 wakeup(&scheduler_notify);
440 #ifndef NO_SWAPPING
442 #define swappable(p) \
443 (((p)->p_lock == 0) && \
444 ((p)->p_flag & (P_TRACED|P_SYSTEM|P_SWAPPEDOUT|P_WEXIT)) == 0)
448 * Swap_idle_threshold1 is the guaranteed swapped in time for a process
450 static int swap_idle_threshold1 = 15;
451 SYSCTL_INT(_vm, OID_AUTO, swap_idle_threshold1,
452 CTLFLAG_RW, &swap_idle_threshold1, 0, "");
455 * Swap_idle_threshold2 is the time that a process can be idle before
456 * it will be swapped out, if idle swapping is enabled. Default is
457 * one minute.
459 static int swap_idle_threshold2 = 60;
460 SYSCTL_INT(_vm, OID_AUTO, swap_idle_threshold2,
461 CTLFLAG_RW, &swap_idle_threshold2, 0, "");
464 * Swapout is driven by the pageout daemon. Very simple, we find eligible
465 * procs and mark them as being swapped out. This will cause the kernel
466 * to prefer to pageout those proc's pages first and the procs in question
467 * will not return to user mode until the swapper tells them they can.
469 * If any procs have been sleeping/stopped for at least maxslp seconds,
470 * they are swapped. Else, we swap the longest-sleeping or stopped process,
471 * if any, otherwise the longest-resident process.
474 static int swapout_procs_callback(struct proc *p, void *data);
476 void
477 swapout_procs(int action)
479 allproc_scan(swapout_procs_callback, &action);
482 static int
483 swapout_procs_callback(struct proc *p, void *data)
485 struct vmspace *vm;
486 struct lwp *lp;
487 int action = *(int *)data;
488 int minslp = -1;
490 if (!swappable(p))
491 return(0);
493 vm = p->p_vmspace;
496 * We only consider active processes.
498 if (p->p_stat != SACTIVE && p->p_stat != SSTOP)
499 return(0);
501 FOREACH_LWP_IN_PROC(lp, p) {
503 * do not swap out a realtime process
505 if (RTP_PRIO_IS_REALTIME(lp->lwp_rtprio.type))
506 return(0);
509 * Guarentee swap_idle_threshold time in memory
511 if (lp->lwp_slptime < swap_idle_threshold1)
512 return(0);
515 * If the system is under memory stress, or if we
516 * are swapping idle processes >= swap_idle_threshold2,
517 * then swap the process out.
519 if (((action & VM_SWAP_NORMAL) == 0) &&
520 (((action & VM_SWAP_IDLE) == 0) ||
521 (lp->lwp_slptime < swap_idle_threshold2))) {
522 return(0);
525 if (minslp == -1 || lp->lwp_slptime < minslp)
526 minslp = lp->lwp_slptime;
529 sysref_get(&vm->vm_sysref);
532 * If the process has been asleep for awhile, swap
533 * it out.
535 if ((action & VM_SWAP_NORMAL) ||
536 ((action & VM_SWAP_IDLE) &&
537 (minslp > swap_idle_threshold2))) {
538 swapout(p);
542 * cleanup our reference
544 sysref_put(&vm->vm_sysref);
546 return(0);
549 static void
550 swapout(struct proc *p)
552 #ifdef INVARIANTS
553 if (swap_debug)
554 kprintf("swapping out %d (%s)\n", p->p_pid, p->p_comm);
555 #endif
556 ++p->p_ru.ru_nswap;
558 * remember the process resident count
560 p->p_vmspace->vm_swrss = vmspace_resident_count(p->p_vmspace);
561 p->p_flag |= P_SWAPPEDOUT;
562 p->p_swtime = 0;
565 #endif /* !NO_SWAPPING */