xref: /freebsd/sys/kern/subr_param.c (revision 0f2bd1e89db1a2f09268edea21e0ead329e092df)
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("$FreeBSD$");
39 
40 #include "opt_param.h"
41 #include "opt_maxusers.h"
42 
43 #include <sys/limits.h>
44 #include <sys/param.h>
45 #include <sys/systm.h>
46 #include <sys/kernel.h>
47 #include <sys/sysctl.h>
48 
49 #include <vm/vm_param.h>
50 
51 /*
52  * System parameter formulae.
53  */
54 
55 #ifndef HZ
56 #  if defined(__mips__) || defined(__arm__)
57 #    define	HZ 100
58 #  else
59 #    define	HZ 1000
60 #  endif
61 #  ifndef HZ_VM
62 #    define	HZ_VM 100
63 #  endif
64 #else
65 #  ifndef HZ_VM
66 #    define	HZ_VM HZ
67 #  endif
68 #endif
69 #define	NPROC (20 + 16 * maxusers)
70 #ifndef NBUF
71 #define NBUF 0
72 #endif
73 #ifndef MAXFILES
74 #define	MAXFILES (maxproc * 2)
75 #endif
76 
77 static int sysctl_kern_vm_guest(SYSCTL_HANDLER_ARGS);
78 
79 int	hz;
80 int	tick;
81 int	maxusers;			/* base tunable */
82 int	maxproc;			/* maximum # of processes */
83 int	maxprocperuid;			/* max # of procs per user */
84 int	maxfiles;			/* sys. wide open files limit */
85 int	maxfilesperproc;		/* per-proc open files limit */
86 int	ncallout;			/* maximum # of timer events */
87 int	nbuf;
88 int	ngroups_max;			/* max # groups per process */
89 int	nswbuf;
90 long	maxswzone;			/* max swmeta KVA storage */
91 long	maxbcache;			/* max buffer cache KVA storage */
92 long	maxpipekva;			/* Limit on pipe KVA */
93 int 	vm_guest;			/* Running as virtual machine guest? */
94 u_long	maxtsiz;			/* max text size */
95 u_long	dfldsiz;			/* initial data size limit */
96 u_long	maxdsiz;			/* max data size */
97 u_long	dflssiz;			/* initial stack size limit */
98 u_long	maxssiz;			/* max stack size */
99 u_long	sgrowsiz;			/* amount to grow stack */
100 
101 SYSCTL_INT(_kern, OID_AUTO, hz, CTLFLAG_RDTUN, &hz, 0,
102     "Number of clock ticks per second");
103 SYSCTL_INT(_kern, OID_AUTO, ncallout, CTLFLAG_RDTUN, &ncallout, 0,
104     "Number of pre-allocated timer events");
105 SYSCTL_INT(_kern, OID_AUTO, nbuf, CTLFLAG_RDTUN, &nbuf, 0,
106     "Number of buffers in the buffer cache");
107 SYSCTL_INT(_kern, OID_AUTO, nswbuf, CTLFLAG_RDTUN, &nswbuf, 0,
108     "Number of swap buffers");
109 SYSCTL_LONG(_kern, OID_AUTO, maxswzone, CTLFLAG_RDTUN, &maxswzone, 0,
110     "Maximum memory for swap metadata");
111 SYSCTL_LONG(_kern, OID_AUTO, maxbcache, CTLFLAG_RDTUN, &maxbcache, 0,
112     "Maximum value of vfs.maxbufspace");
113 SYSCTL_ULONG(_kern, OID_AUTO, maxtsiz, CTLFLAG_RDTUN, &maxtsiz, 0,
114     "Maximum text size");
115 SYSCTL_ULONG(_kern, OID_AUTO, dfldsiz, CTLFLAG_RDTUN, &dfldsiz, 0,
116     "Initial data size limit");
117 SYSCTL_ULONG(_kern, OID_AUTO, maxdsiz, CTLFLAG_RDTUN, &maxdsiz, 0,
118     "Maximum data size");
119 SYSCTL_ULONG(_kern, OID_AUTO, dflssiz, CTLFLAG_RDTUN, &dflssiz, 0,
120     "Initial stack size limit");
121 SYSCTL_ULONG(_kern, OID_AUTO, maxssiz, CTLFLAG_RDTUN, &maxssiz, 0,
122     "Maximum stack size");
123 SYSCTL_ULONG(_kern, OID_AUTO, sgrowsiz, CTLFLAG_RDTUN, &sgrowsiz, 0,
124     "Amount to grow stack on a stack fault");
125 SYSCTL_PROC(_kern, OID_AUTO, vm_guest, CTLFLAG_RD | CTLTYPE_STRING,
126     NULL, 0, sysctl_kern_vm_guest, "A",
127     "Virtual machine guest detected? (none|generic|xen)");
128 
129 /*
130  * These have to be allocated somewhere; allocating
131  * them here forces loader errors if this file is omitted
132  * (if they've been externed everywhere else; hah!).
133  */
134 struct	buf *swbuf;
135 
136 /*
137  * The elements of this array are ordered based upon the values of the
138  * corresponding enum VM_GUEST members.
139  */
140 static const char *const vm_guest_sysctl_names[] = {
141 	"none",
142 	"generic",
143 	"xen",
144 	NULL
145 };
146 
147 #ifndef XEN
148 static const char *const vm_bnames[] = {
149 	"QEMU",				/* QEMU */
150 	"Plex86",			/* Plex86 */
151 	"Bochs",			/* Bochs */
152 	"Xen",				/* Xen */
153 	NULL
154 };
155 
156 static const char *const vm_pnames[] = {
157 	"VMware Virtual Platform",	/* VMWare VM */
158 	"Virtual Machine",		/* Microsoft VirtualPC */
159 	"VirtualBox",			/* Sun xVM VirtualBox */
160 	"Parallels Virtual Platform",	/* Parallels VM */
161 	NULL
162 };
163 
164 
165 /*
166  * Detect known Virtual Machine hosts by inspecting the emulated BIOS.
167  */
168 static enum VM_GUEST
169 detect_virtual(void)
170 {
171 	char *sysenv;
172 	int i;
173 
174 	sysenv = getenv("smbios.bios.vendor");
175 	if (sysenv != NULL) {
176 		for (i = 0; vm_bnames[i] != NULL; i++)
177 			if (strcmp(sysenv, vm_bnames[i]) == 0) {
178 				freeenv(sysenv);
179 				return (VM_GUEST_VM);
180 			}
181 		freeenv(sysenv);
182 	}
183 	sysenv = getenv("smbios.system.product");
184 	if (sysenv != NULL) {
185 		for (i = 0; vm_pnames[i] != NULL; i++)
186 			if (strcmp(sysenv, vm_pnames[i]) == 0) {
187 				freeenv(sysenv);
188 				return (VM_GUEST_VM);
189 			}
190 		freeenv(sysenv);
191 	}
192 	return (VM_GUEST_NO);
193 }
194 #endif
195 
196 /*
197  * Boot time overrides that are not scaled against main memory
198  */
199 void
200 init_param1(void)
201 {
202 #ifndef XEN
203 	vm_guest = detect_virtual();
204 #else
205 	vm_guest = VM_GUEST_XEN;
206 #endif
207 	hz = -1;
208 	TUNABLE_INT_FETCH("kern.hz", &hz);
209 	if (hz == -1)
210 		hz = vm_guest > VM_GUEST_NO ? HZ_VM : HZ;
211 	tick = 1000000 / hz;
212 
213 #ifdef VM_SWZONE_SIZE_MAX
214 	maxswzone = VM_SWZONE_SIZE_MAX;
215 #endif
216 	TUNABLE_LONG_FETCH("kern.maxswzone", &maxswzone);
217 #ifdef VM_BCACHE_SIZE_MAX
218 	maxbcache = VM_BCACHE_SIZE_MAX;
219 #endif
220 	TUNABLE_LONG_FETCH("kern.maxbcache", &maxbcache);
221 
222 	maxtsiz = MAXTSIZ;
223 	TUNABLE_ULONG_FETCH("kern.maxtsiz", &maxtsiz);
224 	dfldsiz = DFLDSIZ;
225 	TUNABLE_ULONG_FETCH("kern.dfldsiz", &dfldsiz);
226 	maxdsiz = MAXDSIZ;
227 	TUNABLE_ULONG_FETCH("kern.maxdsiz", &maxdsiz);
228 	dflssiz = DFLSSIZ;
229 	TUNABLE_ULONG_FETCH("kern.dflssiz", &dflssiz);
230 	maxssiz = MAXSSIZ;
231 	TUNABLE_ULONG_FETCH("kern.maxssiz", &maxssiz);
232 	sgrowsiz = SGROWSIZ;
233 	TUNABLE_ULONG_FETCH("kern.sgrowsiz", &sgrowsiz);
234 
235 	/*
236 	 * Let the administrator set {NGROUPS_MAX}, but disallow values
237 	 * less than NGROUPS_MAX which would violate POSIX.1-2008 or
238 	 * greater than INT_MAX-1 which would result in overflow.
239 	 */
240 	ngroups_max = NGROUPS_MAX;
241 	TUNABLE_INT_FETCH("kern.ngroups", &ngroups_max);
242 	if (ngroups_max < NGROUPS_MAX)
243 		ngroups_max = NGROUPS_MAX;
244 }
245 
246 /*
247  * Boot time overrides that are scaled against main memory
248  */
249 void
250 init_param2(long physpages)
251 {
252 
253 	/* Base parameters */
254 	maxusers = MAXUSERS;
255 	TUNABLE_INT_FETCH("kern.maxusers", &maxusers);
256 	if (maxusers == 0) {
257 		maxusers = physpages / (2 * 1024 * 1024 / PAGE_SIZE);
258 		if (maxusers < 32)
259 			maxusers = 32;
260 		if (maxusers > 384)
261 			maxusers = 384;
262 	}
263 
264 	/*
265 	 * The following can be overridden after boot via sysctl.  Note:
266 	 * unless overriden, these macros are ultimately based on maxusers.
267 	 */
268 	maxproc = NPROC;
269 	TUNABLE_INT_FETCH("kern.maxproc", &maxproc);
270 	/*
271 	 * Limit maxproc so that kmap entries cannot be exhausted by
272 	 * processes.
273 	 */
274 	if (maxproc > (physpages / 12))
275 		maxproc = physpages / 12;
276 	maxfiles = MAXFILES;
277 	TUNABLE_INT_FETCH("kern.maxfiles", &maxfiles);
278 	maxprocperuid = (maxproc * 9) / 10;
279 	maxfilesperproc = (maxfiles * 9) / 10;
280 
281 	/*
282 	 * Cannot be changed after boot.
283 	 */
284 	nbuf = NBUF;
285 	TUNABLE_INT_FETCH("kern.nbuf", &nbuf);
286 
287 	ncallout = 16 + maxproc + maxfiles;
288 	TUNABLE_INT_FETCH("kern.ncallout", &ncallout);
289 }
290 
291 /*
292  * Boot time overrides that are scaled against the kmem map
293  */
294 void
295 init_param3(long kmempages)
296 {
297 
298 	/*
299 	 * The default for maxpipekva is max(5% of the kmem map, 512KB).
300 	 * See sys_pipe.c for more details.
301 	 */
302 	maxpipekva = (kmempages / 20) * PAGE_SIZE;
303 	if (maxpipekva < 512 * 1024)
304 		maxpipekva = 512 * 1024;
305 	TUNABLE_LONG_FETCH("kern.ipc.maxpipekva", &maxpipekva);
306 }
307 
308 /*
309  * Sysctl stringiying handler for kern.vm_guest.
310  */
311 static int
312 sysctl_kern_vm_guest(SYSCTL_HANDLER_ARGS)
313 {
314 	return (SYSCTL_OUT(req, vm_guest_sysctl_names[vm_guest],
315 	    strlen(vm_guest_sysctl_names[vm_guest])));
316 }
317