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/8.4/sys/kern/subr_param.c 246401 2013-02-06 13:14:30Z zont $");
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
79 static int sysctl_kern_vm_guest(SYSCTL_HANDLER_ARGS);
80
81 int hz;
82 int tick;
83 int maxusers; /* base tunable */
84 int maxproc; /* maximum # of processes */
85 int maxprocperuid; /* max # of procs per user */
86 int maxfiles; /* sys. wide open files limit */
87 int maxfilesperproc; /* per-proc open files limit */
88 int msgbufsize; /* size of kernel message buffer */
89 int ncallout; /* maximum # of timer events */
90 int nbuf;
91 int ngroups_max; /* max # groups per process */
92 int nswbuf;
93 long maxswzone; /* max swmeta KVA storage */
94 long maxbcache; /* max buffer cache KVA storage */
95 long maxpipekva; /* Limit on pipe KVA */
96 int vm_guest; /* Running as virtual machine guest? */
97 u_long maxtsiz; /* max text size */
98 u_long dfldsiz; /* initial data size limit */
99 u_long maxdsiz; /* max data size */
100 u_long dflssiz; /* initial stack size limit */
101 u_long maxssiz; /* max stack size */
102 u_long sgrowsiz; /* amount to grow stack */
103
104 SYSCTL_INT(_kern, OID_AUTO, hz, CTLFLAG_RDTUN, &hz, 0,
105 "Number of clock ticks per second");
106 SYSCTL_INT(_kern, OID_AUTO, ncallout, CTLFLAG_RDTUN, &ncallout, 0,
107 "Number of pre-allocated timer events");
108 SYSCTL_INT(_kern, OID_AUTO, nbuf, CTLFLAG_RDTUN, &nbuf, 0,
109 "Number of buffers in the buffer cache");
110 SYSCTL_INT(_kern, OID_AUTO, nswbuf, CTLFLAG_RDTUN, &nswbuf, 0,
111 "Number of swap buffers");
112 SYSCTL_INT(_kern, OID_AUTO, msgbufsize, CTLFLAG_RDTUN, &msgbufsize, 0,
113 "Size of the kernel message buffer");
114 SYSCTL_LONG(_kern, OID_AUTO, maxswzone, CTLFLAG_RDTUN, &maxswzone, 0,
115 "Maximum memory for swap metadata");
116 SYSCTL_LONG(_kern, OID_AUTO, maxbcache, CTLFLAG_RDTUN, &maxbcache, 0,
117 "Maximum value of vfs.maxbufspace");
118 SYSCTL_ULONG(_kern, OID_AUTO, maxtsiz, CTLFLAG_RW | CTLFLAG_TUN, &maxtsiz, 0,
119 "Maximum text size");
120 SYSCTL_ULONG(_kern, OID_AUTO, dfldsiz, CTLFLAG_RW | CTLFLAG_TUN, &dfldsiz, 0,
121 "Initial data size limit");
122 SYSCTL_ULONG(_kern, OID_AUTO, maxdsiz, CTLFLAG_RW | CTLFLAG_TUN, &maxdsiz, 0,
123 "Maximum data size");
124 SYSCTL_ULONG(_kern, OID_AUTO, dflssiz, CTLFLAG_RW | CTLFLAG_TUN, &dflssiz, 0,
125 "Initial stack size limit");
126 SYSCTL_ULONG(_kern, OID_AUTO, maxssiz, CTLFLAG_RW | CTLFLAG_TUN, &maxssiz, 0,
127 "Maximum stack size");
128 SYSCTL_ULONG(_kern, OID_AUTO, sgrowsiz, CTLFLAG_RW | CTLFLAG_TUN, &sgrowsiz, 0,
129 "Amount to grow stack on a stack fault");
130 SYSCTL_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 */
139 struct 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 */
145 static const char *const vm_guest_sysctl_names[] = {
146 "none",
147 "generic",
148 "xen",
149 NULL
150 };
151
152 #ifndef XEN
153 static const char *const vm_bnames[] = {
154 "QEMU", /* QEMU */
155 "Plex86", /* Plex86 */
156 "Bochs", /* Bochs */
157 "Xen", /* Xen */
158 "Seabios", /* KVM */
159 NULL
160 };
161
162 static const char *const vm_pnames[] = {
163 "VMware Virtual Platform", /* VMWare VM */
164 "Virtual Machine", /* Microsoft VirtualPC */
165 "VirtualBox", /* Sun xVM VirtualBox */
166 "Parallels Virtual Platform", /* Parallels VM */
167 "KVM", /* KVM */
168 NULL
169 };
170
171
172 /*
173 * Detect known Virtual Machine hosts by inspecting the emulated BIOS.
174 */
175 static enum VM_GUEST
176 detect_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 */
206 void
207 init_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 */
258 void
259 init_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 /*
301 * Boot time overrides that are scaled against the kmem map
302 */
303 void
304 init_param3(long kmempages)
305 {
306
307 /*
308 * The default for maxpipekva is max(5% of the kmem map, 512KB).
309 * See sys_pipe.c for more details.
310 */
311 maxpipekva = (kmempages / 20) * PAGE_SIZE;
312 if (maxpipekva < 512 * 1024)
313 maxpipekva = 512 * 1024;
314 TUNABLE_LONG_FETCH("kern.ipc.maxpipekva", &maxpipekva);
315 }
316
317 /*
318 * Sysctl stringiying handler for kern.vm_guest.
319 */
320 static int
321 sysctl_kern_vm_guest(SYSCTL_HANDLER_ARGS)
322 {
323 return (SYSCTL_OUT(req, vm_guest_sysctl_names[vm_guest],
324 strlen(vm_guest_sysctl_names[vm_guest])));
325 }
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