subr_param.c revision 217688 
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 217688 2011-01-21 10:26:26Z pluknet $");
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_param.h>
52
53/*
54 * System parameter formulae.
55 */
56
57#ifndef HZ
58#  if defined(__mips__) || defined(__arm__)
59#    define	HZ 100
60#  else
61#    define	HZ 1000
62#  endif
63#  ifndef HZ_VM
64#    define	HZ_VM 100
65#  endif
66#else
67#  ifndef HZ_VM
68#    define	HZ_VM HZ
69#  endif
70#endif
71#define	NPROC (20 + 16 * maxusers)
72#ifndef NBUF
73#define NBUF 0
74#endif
75#ifndef MAXFILES
76#define	MAXFILES (maxproc * 2)
77#endif
78
79static int sysctl_kern_vm_guest(SYSCTL_HANDLER_ARGS);
80
81int	hz;
82int	tick;
83int	maxusers;			/* base tunable */
84int	maxproc;			/* maximum # of processes */
85int	maxprocperuid;			/* max # of procs per user */
86int	maxfiles;			/* sys. wide open files limit */
87int	maxfilesperproc;		/* per-proc open files limit */
88int	msgbufsize;			/* size of kernel message buffer */
89int	ncallout;			/* maximum # of timer events */
90int	nbuf;
91int	ngroups_max;			/* max # groups per process */
92int	nswbuf;
93long	maxswzone;			/* max swmeta KVA storage */
94long	maxbcache;			/* max buffer cache KVA storage */
95long	maxpipekva;			/* Limit on pipe KVA */
96int 	vm_guest;			/* Running as virtual machine guest? */
97u_long	maxtsiz;			/* max text size */
98u_long	dfldsiz;			/* initial data size limit */
99u_long	maxdsiz;			/* max data size */
100u_long	dflssiz;			/* initial stack size limit */
101u_long	maxssiz;			/* max stack size */
102u_long	sgrowsiz;			/* amount to grow stack */
103
104SYSCTL_INT(_kern, OID_AUTO, hz, CTLFLAG_RDTUN, &hz, 0,
105    "Number of clock ticks per second");
106SYSCTL_INT(_kern, OID_AUTO, ncallout, CTLFLAG_RDTUN, &ncallout, 0,
107    "Number of pre-allocated timer events");
108SYSCTL_INT(_kern, OID_AUTO, nbuf, CTLFLAG_RDTUN, &nbuf, 0,
109    "Number of buffers in the buffer cache");
110SYSCTL_INT(_kern, OID_AUTO, nswbuf, CTLFLAG_RDTUN, &nswbuf, 0,
111    "Number of swap buffers");
112SYSCTL_INT(_kern, OID_AUTO, msgbufsize, CTLFLAG_RDTUN, &msgbufsize, 0,
113    "Size of the kernel message buffer");
114SYSCTL_LONG(_kern, OID_AUTO, maxswzone, CTLFLAG_RDTUN, &maxswzone, 0,
115    "Maximum memory for swap metadata");
116SYSCTL_LONG(_kern, OID_AUTO, maxbcache, CTLFLAG_RDTUN, &maxbcache, 0,
117    "Maximum value of vfs.maxbufspace");
118SYSCTL_ULONG(_kern, OID_AUTO, maxtsiz, CTLFLAG_RDTUN, &maxtsiz, 0,
119    "Maximum text size");
120SYSCTL_ULONG(_kern, OID_AUTO, dfldsiz, CTLFLAG_RDTUN, &dfldsiz, 0,
121    "Initial data size limit");
122SYSCTL_ULONG(_kern, OID_AUTO, maxdsiz, CTLFLAG_RDTUN, &maxdsiz, 0,
123    "Maximum data size");
124SYSCTL_ULONG(_kern, OID_AUTO, dflssiz, CTLFLAG_RDTUN, &dflssiz, 0,
125    "Initial stack size limit");
126SYSCTL_ULONG(_kern, OID_AUTO, maxssiz, CTLFLAG_RDTUN, &maxssiz, 0,
127    "Maximum stack size");
128SYSCTL_ULONG(_kern, OID_AUTO, sgrowsiz, CTLFLAG_RDTUN, &sgrowsiz, 0,
129    "Amount to grow stack on a stack fault");
130SYSCTL_PROC(_kern, OID_AUTO, vm_guest, CTLFLAG_RD | CTLTYPE_STRING,
131    NULL, 0, sysctl_kern_vm_guest, "A",
132    "Virtual machine guest detected? (none|generic|xen)");
133
134/*
135 * These have to be allocated somewhere; allocating
136 * them here forces loader errors if this file is omitted
137 * (if they've been externed everywhere else; hah!).
138 */
139struct	buf *swbuf;
140
141/*
142 * The elements of this array are ordered based upon the values of the
143 * corresponding enum VM_GUEST members.
144 */
145static const char *const vm_guest_sysctl_names[] = {
146	"none",
147	"generic",
148	"xen",
149	NULL
150};
151
152#ifndef XEN
153static const char *const vm_bnames[] = {
154	"QEMU",				/* QEMU */
155	"Plex86",			/* Plex86 */
156	"Bochs",			/* Bochs */
157	"Xen",				/* Xen */
158	NULL
159};
160
161static const char *const vm_pnames[] = {
162	"VMware Virtual Platform",	/* VMWare VM */
163	"Virtual Machine",		/* Microsoft VirtualPC */
164	"VirtualBox",			/* Sun xVM VirtualBox */
165	"Parallels Virtual Platform",	/* Parallels VM */
166	NULL
167};
168
169
170/*
171 * Detect known Virtual Machine hosts by inspecting the emulated BIOS.
172 */
173static enum VM_GUEST
174detect_virtual(void)
175{
176	char *sysenv;
177	int i;
178
179	sysenv = getenv("smbios.bios.vendor");
180	if (sysenv != NULL) {
181		for (i = 0; vm_bnames[i] != NULL; i++)
182			if (strcmp(sysenv, vm_bnames[i]) == 0) {
183				freeenv(sysenv);
184				return (VM_GUEST_VM);
185			}
186		freeenv(sysenv);
187	}
188	sysenv = getenv("smbios.system.product");
189	if (sysenv != NULL) {
190		for (i = 0; vm_pnames[i] != NULL; i++)
191			if (strcmp(sysenv, vm_pnames[i]) == 0) {
192				freeenv(sysenv);
193				return (VM_GUEST_VM);
194			}
195		freeenv(sysenv);
196	}
197	return (VM_GUEST_NO);
198}
199#endif
200
201/*
202 * Boot time overrides that are not scaled against main memory
203 */
204void
205init_param1(void)
206{
207#ifndef XEN
208	vm_guest = detect_virtual();
209#else
210	vm_guest = VM_GUEST_XEN;
211#endif
212	hz = -1;
213	TUNABLE_INT_FETCH("kern.hz", &hz);
214	if (hz == -1)
215		hz = vm_guest > VM_GUEST_NO ? HZ_VM : HZ;
216	tick = 1000000 / hz;
217
218#ifdef VM_SWZONE_SIZE_MAX
219	maxswzone = VM_SWZONE_SIZE_MAX;
220#endif
221	TUNABLE_LONG_FETCH("kern.maxswzone", &maxswzone);
222#ifdef VM_BCACHE_SIZE_MAX
223	maxbcache = VM_BCACHE_SIZE_MAX;
224#endif
225	TUNABLE_LONG_FETCH("kern.maxbcache", &maxbcache);
226	msgbufsize = MSGBUF_SIZE;
227	TUNABLE_INT_FETCH("kern.msgbufsize", &msgbufsize);
228
229	maxtsiz = MAXTSIZ;
230	TUNABLE_ULONG_FETCH("kern.maxtsiz", &maxtsiz);
231	dfldsiz = DFLDSIZ;
232	TUNABLE_ULONG_FETCH("kern.dfldsiz", &dfldsiz);
233	maxdsiz = MAXDSIZ;
234	TUNABLE_ULONG_FETCH("kern.maxdsiz", &maxdsiz);
235	dflssiz = DFLSSIZ;
236	TUNABLE_ULONG_FETCH("kern.dflssiz", &dflssiz);
237	maxssiz = MAXSSIZ;
238	TUNABLE_ULONG_FETCH("kern.maxssiz", &maxssiz);
239	sgrowsiz = SGROWSIZ;
240	TUNABLE_ULONG_FETCH("kern.sgrowsiz", &sgrowsiz);
241
242	/*
243	 * Let the administrator set {NGROUPS_MAX}, but disallow values
244	 * less than NGROUPS_MAX which would violate POSIX.1-2008 or
245	 * greater than INT_MAX-1 which would result in overflow.
246	 */
247	ngroups_max = NGROUPS_MAX;
248	TUNABLE_INT_FETCH("kern.ngroups", &ngroups_max);
249	if (ngroups_max < NGROUPS_MAX)
250		ngroups_max = NGROUPS_MAX;
251}
252
253/*
254 * Boot time overrides that are scaled against main memory
255 */
256void
257init_param2(long physpages)
258{
259
260	/* Base parameters */
261	maxusers = MAXUSERS;
262	TUNABLE_INT_FETCH("kern.maxusers", &maxusers);
263	if (maxusers == 0) {
264		maxusers = physpages / (2 * 1024 * 1024 / PAGE_SIZE);
265		if (maxusers < 32)
266			maxusers = 32;
267		if (maxusers > 384)
268			maxusers = 384;
269	}
270
271	/*
272	 * The following can be overridden after boot via sysctl.  Note:
273	 * unless overriden, these macros are ultimately based on maxusers.
274	 */
275	maxproc = NPROC;
276	TUNABLE_INT_FETCH("kern.maxproc", &maxproc);
277	/*
278	 * Limit maxproc so that kmap entries cannot be exhausted by
279	 * processes.
280	 */
281	if (maxproc > (physpages / 12))
282		maxproc = physpages / 12;
283	maxfiles = MAXFILES;
284	TUNABLE_INT_FETCH("kern.maxfiles", &maxfiles);
285	maxprocperuid = (maxproc * 9) / 10;
286	maxfilesperproc = (maxfiles * 9) / 10;
287
288	/*
289	 * Cannot be changed after boot.
290	 */
291	nbuf = NBUF;
292	TUNABLE_INT_FETCH("kern.nbuf", &nbuf);
293
294	ncallout = 16 + maxproc + maxfiles;
295	TUNABLE_INT_FETCH("kern.ncallout", &ncallout);
296}
297
298/*
299 * Boot time overrides that are scaled against the kmem map
300 */
301void
302init_param3(long kmempages)
303{
304
305	/*
306	 * The default for maxpipekva is max(5% of the kmem map, 512KB).
307	 * See sys_pipe.c for more details.
308	 */
309	maxpipekva = (kmempages / 20) * PAGE_SIZE;
310	if (maxpipekva < 512 * 1024)
311		maxpipekva = 512 * 1024;
312	TUNABLE_LONG_FETCH("kern.ipc.maxpipekva", &maxpipekva);
313}
314
315/*
316 * Sysctl stringiying handler for kern.vm_guest.
317 */
318static int
319sysctl_kern_vm_guest(SYSCTL_HANDLER_ARGS)
320{
321	return (SYSCTL_OUT(req, vm_guest_sysctl_names[vm_guest],
322	    strlen(vm_guest_sysctl_names[vm_guest])));
323}
324