FreeBSD/Linux Kernel Cross Reference
sys/kern/subr_param.c
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: releng/8.2/sys/kern/subr_param.c 211891 2010-08-27 18:55:24Z jhb $");
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 }
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