subr_param.c revision 219920 
1/*-
2 * Copyright (c) 1980, 1986, 1989, 1993
3 *	The Regents of the University of California.  All rights reserved.
4 * (c) UNIX System Laboratories, Inc.
5 * All or some portions of this file are derived from material licensed
6 * to the University of California by American Telephone and Telegraph
7 * Co. or Unix System Laboratories, Inc. and are reproduced herein with
8 * the permission of UNIX System Laboratories, Inc.
9 *
10 * Redistribution and use in source and binary forms, with or without
11 * modification, are permitted provided that the following conditions
12 * are met:
13 * 1. Redistributions of source code must retain the above copyright
14 *    notice, this list of conditions and the following disclaimer.
15 * 2. Redistributions in binary form must reproduce the above copyright
16 *    notice, this list of conditions and the following disclaimer in the
17 *    documentation and/or other materials provided with the distribution.
18 * 4. Neither the name of the University nor the names of its contributors
19 *    may be used to endorse or promote products derived from this software
20 *    without specific prior written permission.
21 *
22 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
23 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
24 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
25 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
26 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
27 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
28 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
29 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
30 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
31 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
32 * SUCH DAMAGE.
33 *
34 *	@(#)param.c	8.3 (Berkeley) 8/20/94
35 */
36
37#include <sys/cdefs.h>
38__FBSDID("$FreeBSD: head/sys/kern/subr_param.c 219920 2011-03-23 16:38:29Z alc $");
39
40#include "opt_param.h"
41#include "opt_msgbuf.h"
42#include "opt_maxusers.h"
43
44#include <sys/limits.h>
45#include <sys/param.h>
46#include <sys/systm.h>
47#include <sys/kernel.h>
48#include <sys/sysctl.h>
49#include <sys/msgbuf.h>
50
51#include <vm/vm.h>
52#include <vm/vm_param.h>
53#include <vm/pmap.h>
54
55/*
56 * System parameter formulae.
57 */
58
59#ifndef HZ
60#  if defined(__mips__) || defined(__arm__)
61#    define	HZ 100
62#  else
63#    define	HZ 1000
64#  endif
65#  ifndef HZ_VM
66#    define	HZ_VM 100
67#  endif
68#else
69#  ifndef HZ_VM
70#    define	HZ_VM HZ
71#  endif
72#endif
73#define	NPROC (20 + 16 * maxusers)
74#ifndef NBUF
75#define NBUF 0
76#endif
77#ifndef MAXFILES
78#define	MAXFILES (maxproc * 2)
79#endif
80
81static int sysctl_kern_vm_guest(SYSCTL_HANDLER_ARGS);
82
83int	hz;
84int	tick;
85int	maxusers;			/* base tunable */
86int	maxproc;			/* maximum # of processes */
87int	maxprocperuid;			/* max # of procs per user */
88int	maxfiles;			/* sys. wide open files limit */
89int	maxfilesperproc;		/* per-proc open files limit */
90int	msgbufsize;			/* size of kernel message buffer */
91int	ncallout;			/* maximum # of timer events */
92int	nbuf;
93int	ngroups_max;			/* max # groups per process */
94int	nswbuf;
95long	maxswzone;			/* max swmeta KVA storage */
96long	maxbcache;			/* max buffer cache KVA storage */
97long	maxpipekva;			/* Limit on pipe KVA */
98int 	vm_guest;			/* Running as virtual machine guest? */
99u_long	maxtsiz;			/* max text size */
100u_long	dfldsiz;			/* initial data size limit */
101u_long	maxdsiz;			/* max data size */
102u_long	dflssiz;			/* initial stack size limit */
103u_long	maxssiz;			/* max stack size */
104u_long	sgrowsiz;			/* amount to grow stack */
105
106SYSCTL_INT(_kern, OID_AUTO, hz, CTLFLAG_RDTUN, &hz, 0,
107    "Number of clock ticks per second");
108SYSCTL_INT(_kern, OID_AUTO, ncallout, CTLFLAG_RDTUN, &ncallout, 0,
109    "Number of pre-allocated timer events");
110SYSCTL_INT(_kern, OID_AUTO, nbuf, CTLFLAG_RDTUN, &nbuf, 0,
111    "Number of buffers in the buffer cache");
112SYSCTL_INT(_kern, OID_AUTO, nswbuf, CTLFLAG_RDTUN, &nswbuf, 0,
113    "Number of swap buffers");
114SYSCTL_INT(_kern, OID_AUTO, msgbufsize, CTLFLAG_RDTUN, &msgbufsize, 0,
115    "Size of the kernel message buffer");
116SYSCTL_LONG(_kern, OID_AUTO, maxswzone, CTLFLAG_RDTUN, &maxswzone, 0,
117    "Maximum memory for swap metadata");
118SYSCTL_LONG(_kern, OID_AUTO, maxbcache, CTLFLAG_RDTUN, &maxbcache, 0,
119    "Maximum value of vfs.maxbufspace");
120SYSCTL_ULONG(_kern, OID_AUTO, maxtsiz, CTLFLAG_RDTUN, &maxtsiz, 0,
121    "Maximum text size");
122SYSCTL_ULONG(_kern, OID_AUTO, dfldsiz, CTLFLAG_RDTUN, &dfldsiz, 0,
123    "Initial data size limit");
124SYSCTL_ULONG(_kern, OID_AUTO, maxdsiz, CTLFLAG_RDTUN, &maxdsiz, 0,
125    "Maximum data size");
126SYSCTL_ULONG(_kern, OID_AUTO, dflssiz, CTLFLAG_RDTUN, &dflssiz, 0,
127    "Initial stack size limit");
128SYSCTL_ULONG(_kern, OID_AUTO, maxssiz, CTLFLAG_RDTUN, &maxssiz, 0,
129    "Maximum stack size");
130SYSCTL_ULONG(_kern, OID_AUTO, sgrowsiz, CTLFLAG_RDTUN, &sgrowsiz, 0,
131    "Amount to grow stack on a stack fault");
132SYSCTL_PROC(_kern, OID_AUTO, vm_guest, CTLFLAG_RD | CTLTYPE_STRING,
133    NULL, 0, sysctl_kern_vm_guest, "A",
134    "Virtual machine guest detected? (none|generic|xen)");
135
136/*
137 * These have to be allocated somewhere; allocating
138 * them here forces loader errors if this file is omitted
139 * (if they've been externed everywhere else; hah!).
140 */
141struct	buf *swbuf;
142
143/*
144 * The elements of this array are ordered based upon the values of the
145 * corresponding enum VM_GUEST members.
146 */
147static const char *const vm_guest_sysctl_names[] = {
148	"none",
149	"generic",
150	"xen",
151	NULL
152};
153
154#ifndef XEN
155static const char *const vm_bnames[] = {
156	"QEMU",				/* QEMU */
157	"Plex86",			/* Plex86 */
158	"Bochs",			/* Bochs */
159	"Xen",				/* Xen */
160	NULL
161};
162
163static const char *const vm_pnames[] = {
164	"VMware Virtual Platform",	/* VMWare VM */
165	"Virtual Machine",		/* Microsoft VirtualPC */
166	"VirtualBox",			/* Sun xVM VirtualBox */
167	"Parallels Virtual Platform",	/* Parallels VM */
168	NULL
169};
170
171
172/*
173 * Detect known Virtual Machine hosts by inspecting the emulated BIOS.
174 */
175static enum VM_GUEST
176detect_virtual(void)
177{
178	char *sysenv;
179	int i;
180
181	sysenv = getenv("smbios.bios.vendor");
182	if (sysenv != NULL) {
183		for (i = 0; vm_bnames[i] != NULL; i++)
184			if (strcmp(sysenv, vm_bnames[i]) == 0) {
185				freeenv(sysenv);
186				return (VM_GUEST_VM);
187			}
188		freeenv(sysenv);
189	}
190	sysenv = getenv("smbios.system.product");
191	if (sysenv != NULL) {
192		for (i = 0; vm_pnames[i] != NULL; i++)
193			if (strcmp(sysenv, vm_pnames[i]) == 0) {
194				freeenv(sysenv);
195				return (VM_GUEST_VM);
196			}
197		freeenv(sysenv);
198	}
199	return (VM_GUEST_NO);
200}
201#endif
202
203/*
204 * Boot time overrides that are not scaled against main memory
205 */
206void
207init_param1(void)
208{
209#ifndef XEN
210	vm_guest = detect_virtual();
211#else
212	vm_guest = VM_GUEST_XEN;
213#endif
214	hz = -1;
215	TUNABLE_INT_FETCH("kern.hz", &hz);
216	if (hz == -1)
217		hz = vm_guest > VM_GUEST_NO ? HZ_VM : HZ;
218	tick = 1000000 / hz;
219
220#ifdef VM_SWZONE_SIZE_MAX
221	maxswzone = VM_SWZONE_SIZE_MAX;
222#endif
223	TUNABLE_LONG_FETCH("kern.maxswzone", &maxswzone);
224#ifdef VM_BCACHE_SIZE_MAX
225	maxbcache = VM_BCACHE_SIZE_MAX;
226#endif
227	TUNABLE_LONG_FETCH("kern.maxbcache", &maxbcache);
228	msgbufsize = MSGBUF_SIZE;
229	TUNABLE_INT_FETCH("kern.msgbufsize", &msgbufsize);
230
231	maxtsiz = MAXTSIZ;
232	TUNABLE_ULONG_FETCH("kern.maxtsiz", &maxtsiz);
233	dfldsiz = DFLDSIZ;
234	TUNABLE_ULONG_FETCH("kern.dfldsiz", &dfldsiz);
235	maxdsiz = MAXDSIZ;
236	TUNABLE_ULONG_FETCH("kern.maxdsiz", &maxdsiz);
237	dflssiz = DFLSSIZ;
238	TUNABLE_ULONG_FETCH("kern.dflssiz", &dflssiz);
239	maxssiz = MAXSSIZ;
240	TUNABLE_ULONG_FETCH("kern.maxssiz", &maxssiz);
241	sgrowsiz = SGROWSIZ;
242	TUNABLE_ULONG_FETCH("kern.sgrowsiz", &sgrowsiz);
243
244	/*
245	 * Let the administrator set {NGROUPS_MAX}, but disallow values
246	 * less than NGROUPS_MAX which would violate POSIX.1-2008 or
247	 * greater than INT_MAX-1 which would result in overflow.
248	 */
249	ngroups_max = NGROUPS_MAX;
250	TUNABLE_INT_FETCH("kern.ngroups", &ngroups_max);
251	if (ngroups_max < NGROUPS_MAX)
252		ngroups_max = NGROUPS_MAX;
253}
254
255/*
256 * Boot time overrides that are scaled against main memory
257 */
258void
259init_param2(long physpages)
260{
261
262	/* Base parameters */
263	maxusers = MAXUSERS;
264	TUNABLE_INT_FETCH("kern.maxusers", &maxusers);
265	if (maxusers == 0) {
266		maxusers = physpages / (2 * 1024 * 1024 / PAGE_SIZE);
267		if (maxusers < 32)
268			maxusers = 32;
269		if (maxusers > 384)
270			maxusers = 384;
271	}
272
273	/*
274	 * The following can be overridden after boot via sysctl.  Note:
275	 * unless overriden, these macros are ultimately based on maxusers.
276	 */
277	maxproc = NPROC;
278	TUNABLE_INT_FETCH("kern.maxproc", &maxproc);
279	/*
280	 * Limit maxproc so that kmap entries cannot be exhausted by
281	 * processes.
282	 */
283	if (maxproc > (physpages / 12))
284		maxproc = physpages / 12;
285	maxfiles = MAXFILES;
286	TUNABLE_INT_FETCH("kern.maxfiles", &maxfiles);
287	maxprocperuid = (maxproc * 9) / 10;
288	maxfilesperproc = (maxfiles * 9) / 10;
289
290	/*
291	 * Cannot be changed after boot.
292	 */
293	nbuf = NBUF;
294	TUNABLE_INT_FETCH("kern.nbuf", &nbuf);
295
296	ncallout = 16 + maxproc + maxfiles;
297	TUNABLE_INT_FETCH("kern.ncallout", &ncallout);
298
299	/*
300	 * The default for maxpipekva is min(1/64 of the kernel address space,
301	 * max(1/64 of main memory, 512KB)).  See sys_pipe.c for more details.
302	 */
303	maxpipekva = (physpages / 64) * PAGE_SIZE;
304	if (maxpipekva < 512 * 1024)
305		maxpipekva = 512 * 1024;
306	if (maxpipekva > (VM_MAX_KERNEL_ADDRESS - VM_MIN_KERNEL_ADDRESS) / 64)
307		maxpipekva = (VM_MAX_KERNEL_ADDRESS - VM_MIN_KERNEL_ADDRESS) /
308		    64;
309	TUNABLE_LONG_FETCH("kern.ipc.maxpipekva", &maxpipekva);
310}
311
312/*
313 * Sysctl stringiying handler for kern.vm_guest.
314 */
315static int
316sysctl_kern_vm_guest(SYSCTL_HANDLER_ARGS)
317{
318	return (SYSCTL_OUT(req, vm_guest_sysctl_names[vm_guest],
319	    strlen(vm_guest_sysctl_names[vm_guest])));
320}
321