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("$FreeBSD$");
39
40 #include "opt_param.h"
41 #include "opt_maxusers.h"
42
43 #include <sys/param.h>
44 #include <sys/systm.h>
45 #include <sys/kernel.h>
46 #include <sys/sysctl.h>
47
48 #include <vm/vm_param.h>
49
50 /*
51 * System parameter formulae.
52 */
53
54 #ifndef HZ
55 # if defined(__amd64__) || defined(__i386__) || defined(__ia64__) || defined(__sparc64__)
56 # define HZ 1000
57 # else
58 # define HZ 100
59 # endif
60 # ifndef HZ_VM
61 # define HZ_VM 100
62 # endif
63 #else
64 # ifndef HZ_VM
65 # define HZ_VM HZ
66 # endif
67 #endif
68 #define NPROC (20 + 16 * maxusers)
69 #ifndef NBUF
70 #define NBUF 0
71 #endif
72 #ifndef MAXFILES
73 #define MAXFILES (maxproc * 2)
74 #endif
75
76 static int sysctl_kern_vm_guest(SYSCTL_HANDLER_ARGS);
77
78 int hz;
79 int tick;
80 int maxusers; /* base tunable */
81 int maxproc; /* maximum # of processes */
82 int maxprocperuid; /* max # of procs per user */
83 int maxfiles; /* sys. wide open files limit */
84 int maxfilesperproc; /* per-proc open files limit */
85 int ncallout; /* maximum # of timer events */
86 int nbuf;
87 int nswbuf;
88 long maxswzone; /* max swmeta KVA storage */
89 long maxbcache; /* max buffer cache KVA storage */
90 long maxpipekva; /* Limit on pipe KVA */
91 int vm_guest; /* Running as virtual machine guest? */
92 u_long maxtsiz; /* max text size */
93 u_long dfldsiz; /* initial data size limit */
94 u_long maxdsiz; /* max data size */
95 u_long dflssiz; /* initial stack size limit */
96 u_long maxssiz; /* max stack size */
97 u_long sgrowsiz; /* amount to grow stack */
98
99 SYSCTL_INT(_kern, OID_AUTO, hz, CTLFLAG_RDTUN, &hz, 0,
100 "Number of clock ticks per second");
101 SYSCTL_INT(_kern, OID_AUTO, ncallout, CTLFLAG_RDTUN, &ncallout, 0,
102 "Number of pre-allocated timer events");
103 SYSCTL_INT(_kern, OID_AUTO, nbuf, CTLFLAG_RDTUN, &nbuf, 0,
104 "Number of buffers in the buffer cache");
105 SYSCTL_INT(_kern, OID_AUTO, nswbuf, CTLFLAG_RDTUN, &nswbuf, 0,
106 "Number of swap buffers");
107 SYSCTL_LONG(_kern, OID_AUTO, maxswzone, CTLFLAG_RDTUN, &maxswzone, 0,
108 "Maximum memory for swap metadata");
109 SYSCTL_LONG(_kern, OID_AUTO, maxbcache, CTLFLAG_RDTUN, &maxbcache, 0,
110 "Maximum value of vfs.maxbufspace");
111 SYSCTL_ULONG(_kern, OID_AUTO, maxtsiz, CTLFLAG_RDTUN, &maxtsiz, 0,
112 "Maximum text size");
113 SYSCTL_ULONG(_kern, OID_AUTO, dfldsiz, CTLFLAG_RDTUN, &dfldsiz, 0,
114 "Initial data size limit");
115 SYSCTL_ULONG(_kern, OID_AUTO, maxdsiz, CTLFLAG_RDTUN, &maxdsiz, 0,
116 "Maximum data size");
117 SYSCTL_ULONG(_kern, OID_AUTO, dflssiz, CTLFLAG_RDTUN, &dflssiz, 0,
118 "Initial stack size limit");
119 SYSCTL_ULONG(_kern, OID_AUTO, maxssiz, CTLFLAG_RDTUN, &maxssiz, 0,
120 "Maximum stack size");
121 SYSCTL_ULONG(_kern, OID_AUTO, sgrowsiz, CTLFLAG_RDTUN, &sgrowsiz, 0,
122 "Amount to grow stack on a stack fault");
123 SYSCTL_PROC(_kern, OID_AUTO, vm_guest, CTLFLAG_RD | CTLTYPE_STRING,
124 NULL, 0, sysctl_kern_vm_guest, "A",
125 "Virtual machine guest detected? (none|generic)");
126
127 /*
128 * These have to be allocated somewhere; allocating
129 * them here forces loader errors if this file is omitted
130 * (if they've been externed everywhere else; hah!).
131 */
132 struct buf *swbuf;
133
134 /*
135 * The elements of this array are ordered based upon the values of the
136 * corresponding enum VM_GUEST members.
137 */
138 static const char *const vm_guest_sysctl_names[] = {
139 "none",
140 "generic",
141 NULL
142 };
143
144 static const char *const vm_bnames[] = {
145 "QEMU", /* QEMU */
146 "Plex86", /* Plex86 */
147 "Bochs", /* Bochs */
148 "Xen", /* Xen */
149 NULL
150 };
151
152 static const char *const vm_pnames[] = {
153 "VMware Virtual Platform", /* VMWare VM */
154 "Virtual Machine", /* Microsoft VirtualPC */
155 "VirtualBox", /* Sun xVM VirtualBox */
156 "Parallels Virtual Platform", /* Parallels VM */
157 NULL
158 };
159
160
161 /*
162 * Detect known Virtual Machine hosts by inspecting the emulated BIOS.
163 */
164 static enum VM_GUEST
165 detect_virtual(void)
166 {
167 char *sysenv;
168 int i;
169
170 sysenv = getenv("smbios.bios.vendor");
171 if (sysenv != NULL) {
172 for (i = 0; vm_bnames[i] != NULL; i++)
173 if (strcmp(sysenv, vm_bnames[i]) == 0) {
174 freeenv(sysenv);
175 return (VM_GUEST_VM);
176 }
177 freeenv(sysenv);
178 }
179 sysenv = getenv("smbios.system.product");
180 if (sysenv != NULL) {
181 for (i = 0; vm_pnames[i] != NULL; i++)
182 if (strcmp(sysenv, vm_pnames[i]) == 0) {
183 freeenv(sysenv);
184 return (VM_GUEST_VM);
185 }
186 freeenv(sysenv);
187 }
188 return (VM_GUEST_NO);
189 }
190
191 /*
192 * Boot time overrides that are not scaled against main memory
193 */
194 void
195 init_param1(void)
196 {
197
198 vm_guest = detect_virtual();
199 hz = -1;
200 TUNABLE_INT_FETCH("kern.hz", &hz);
201 if (hz == -1)
202 hz = vm_guest > VM_GUEST_NO ? HZ_VM : HZ;
203 tick = 1000000 / hz;
204
205 #ifdef VM_SWZONE_SIZE_MAX
206 maxswzone = VM_SWZONE_SIZE_MAX;
207 #endif
208 TUNABLE_LONG_FETCH("kern.maxswzone", &maxswzone);
209 #ifdef VM_BCACHE_SIZE_MAX
210 maxbcache = VM_BCACHE_SIZE_MAX;
211 #endif
212 TUNABLE_LONG_FETCH("kern.maxbcache", &maxbcache);
213
214 maxtsiz = MAXTSIZ;
215 TUNABLE_ULONG_FETCH("kern.maxtsiz", &maxtsiz);
216 dfldsiz = DFLDSIZ;
217 TUNABLE_ULONG_FETCH("kern.dfldsiz", &dfldsiz);
218 maxdsiz = MAXDSIZ;
219 TUNABLE_ULONG_FETCH("kern.maxdsiz", &maxdsiz);
220 dflssiz = DFLSSIZ;
221 TUNABLE_ULONG_FETCH("kern.dflssiz", &dflssiz);
222 maxssiz = MAXSSIZ;
223 TUNABLE_ULONG_FETCH("kern.maxssiz", &maxssiz);
224 sgrowsiz = SGROWSIZ;
225 TUNABLE_ULONG_FETCH("kern.sgrowsiz", &sgrowsiz);
226 }
227
228 /*
229 * Boot time overrides that are scaled against main memory
230 */
231 void
232 init_param2(long physpages)
233 {
234
235 /* Base parameters */
236 maxusers = MAXUSERS;
237 TUNABLE_INT_FETCH("kern.maxusers", &maxusers);
238 if (maxusers == 0) {
239 maxusers = physpages / (2 * 1024 * 1024 / PAGE_SIZE);
240 if (maxusers < 32)
241 maxusers = 32;
242 if (maxusers > 384)
243 maxusers = 384;
244 }
245
246 /*
247 * The following can be overridden after boot via sysctl. Note:
248 * unless overriden, these macros are ultimately based on maxusers.
249 */
250 maxproc = NPROC;
251 TUNABLE_INT_FETCH("kern.maxproc", &maxproc);
252 /*
253 * Limit maxproc so that kmap entries cannot be exhausted by
254 * processes.
255 */
256 if (maxproc > (physpages / 12))
257 maxproc = physpages / 12;
258 maxfiles = MAXFILES;
259 TUNABLE_INT_FETCH("kern.maxfiles", &maxfiles);
260 maxprocperuid = (maxproc * 9) / 10;
261 maxfilesperproc = (maxfiles * 9) / 10;
262
263 /*
264 * Cannot be changed after boot.
265 */
266 nbuf = NBUF;
267 TUNABLE_INT_FETCH("kern.nbuf", &nbuf);
268
269 ncallout = 16 + maxproc + maxfiles;
270 TUNABLE_INT_FETCH("kern.ncallout", &ncallout);
271 }
272
273 /*
274 * Boot time overrides that are scaled against the kmem map
275 */
276 void
277 init_param3(long kmempages)
278 {
279
280 /*
281 * The default for maxpipekva is max(5% of the kmem map, 512KB).
282 * See sys_pipe.c for more details.
283 */
284 maxpipekva = (kmempages / 20) * PAGE_SIZE;
285 if (maxpipekva < 512 * 1024)
286 maxpipekva = 512 * 1024;
287 TUNABLE_LONG_FETCH("kern.ipc.maxpipekva", &maxpipekva);
288 }
289
290 /*
291 * Sysctl stringiying handler for kern.vm_guest.
292 */
293 static int
294 sysctl_kern_vm_guest(SYSCTL_HANDLER_ARGS)
295 {
296 return (SYSCTL_OUT(req, vm_guest_sysctl_names[vm_guest],
297 strlen(vm_guest_sysctl_names[vm_guest])));
298 }
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