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/8.0/sys/kern/subr_param.c 195430 2009-07-08 01:09:12Z silby $");
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 /* Values of enum VM_GUEST members are used as indices in
77 * vm_guest_sysctl_names */
78 enum VM_GUEST { VM_GUEST_NO = 0, VM_GUEST_VM, VM_GUEST_XEN };
79
80 static int sysctl_kern_vm_guest(SYSCTL_HANDLER_ARGS);
81
82 int hz;
83 int tick;
84 int maxusers; /* base tunable */
85 int maxproc; /* maximum # of processes */
86 int maxprocperuid; /* max # of procs per user */
87 int maxfiles; /* sys. wide open files limit */
88 int maxfilesperproc; /* per-proc open files limit */
89 int ncallout; /* maximum # of timer events */
90 int nbuf;
91 int nswbuf;
92 long maxswzone; /* max swmeta KVA storage */
93 long maxbcache; /* max buffer cache KVA storage */
94 long maxpipekva; /* Limit on pipe KVA */
95 int vm_guest; /* Running as virtual machine guest? */
96 u_long maxtsiz; /* max text size */
97 u_long dfldsiz; /* initial data size limit */
98 u_long maxdsiz; /* max data size */
99 u_long dflssiz; /* initial stack size limit */
100 u_long maxssiz; /* max stack size */
101 u_long sgrowsiz; /* amount to grow stack */
102
103 SYSCTL_INT(_kern, OID_AUTO, hz, CTLFLAG_RDTUN, &hz, 0,
104 "Number of clock ticks per second");
105 SYSCTL_INT(_kern, OID_AUTO, ncallout, CTLFLAG_RDTUN, &ncallout, 0,
106 "Number of pre-allocated timer events");
107 SYSCTL_INT(_kern, OID_AUTO, nbuf, CTLFLAG_RDTUN, &nbuf, 0,
108 "Number of buffers in the buffer cache");
109 SYSCTL_INT(_kern, OID_AUTO, nswbuf, CTLFLAG_RDTUN, &nswbuf, 0,
110 "Number of swap buffers");
111 SYSCTL_LONG(_kern, OID_AUTO, maxswzone, CTLFLAG_RDTUN, &maxswzone, 0,
112 "Maximum memory for swap metadata");
113 SYSCTL_LONG(_kern, OID_AUTO, maxbcache, CTLFLAG_RDTUN, &maxbcache, 0,
114 "Maximum value of vfs.maxbufspace");
115 SYSCTL_ULONG(_kern, OID_AUTO, maxtsiz, CTLFLAG_RDTUN, &maxtsiz, 0,
116 "Maximum text size");
117 SYSCTL_ULONG(_kern, OID_AUTO, dfldsiz, CTLFLAG_RDTUN, &dfldsiz, 0,
118 "Initial data size limit");
119 SYSCTL_ULONG(_kern, OID_AUTO, maxdsiz, CTLFLAG_RDTUN, &maxdsiz, 0,
120 "Maximum data size");
121 SYSCTL_ULONG(_kern, OID_AUTO, dflssiz, CTLFLAG_RDTUN, &dflssiz, 0,
122 "Initial stack size limit");
123 SYSCTL_ULONG(_kern, OID_AUTO, maxssiz, CTLFLAG_RDTUN, &maxssiz, 0,
124 "Maximum stack size");
125 SYSCTL_ULONG(_kern, OID_AUTO, sgrowsiz, CTLFLAG_RDTUN, &sgrowsiz, 0,
126 "Amount to grow stack on a stack fault");
127 SYSCTL_PROC(_kern, OID_AUTO, vm_guest, CTLFLAG_RD | CTLTYPE_STRING,
128 NULL, 0, sysctl_kern_vm_guest, "A",
129 "Virtual machine detected? (none|generic|xen)");
130
131 /*
132 * These have to be allocated somewhere; allocating
133 * them here forces loader errors if this file is omitted
134 * (if they've been externed everywhere else; hah!).
135 */
136 struct buf *swbuf;
137
138 static const char *const vm_guest_sysctl_names[] = {
139 "none",
140 "generic",
141 "xen",
142 NULL
143 };
144
145 #ifndef XEN
146 static const char *const vm_bnames[] = {
147 "QEMU", /* QEMU */
148 "Plex86", /* Plex86 */
149 "Bochs", /* Bochs */
150 NULL
151 };
152
153 static const char *const vm_pnames[] = {
154 "VMware Virtual Platform", /* VMWare VM */
155 "Virtual Machine", /* Microsoft VirtualPC */
156 "VirtualBox", /* Sun xVM VirtualBox */
157 "Parallels Virtual Platform", /* Parallels VM */
158 NULL
159 };
160
161
162 /*
163 * Detect known Virtual Machine hosts by inspecting the emulated BIOS.
164 */
165 static enum VM_GUEST
166 detect_virtual(void)
167 {
168 char *sysenv;
169 int i;
170
171 sysenv = getenv("smbios.bios.vendor");
172 if (sysenv != NULL) {
173 for (i = 0; vm_bnames[i] != NULL; i++)
174 if (strcmp(sysenv, vm_bnames[i]) == 0) {
175 freeenv(sysenv);
176 return (VM_GUEST_VM);
177 }
178 freeenv(sysenv);
179 }
180 sysenv = getenv("smbios.system.product");
181 if (sysenv != NULL) {
182 for (i = 0; vm_pnames[i] != NULL; i++)
183 if (strcmp(sysenv, vm_pnames[i]) == 0) {
184 freeenv(sysenv);
185 return (VM_GUEST_VM);
186 }
187 freeenv(sysenv);
188 }
189 return (VM_GUEST_NO);
190 }
191 #endif
192
193 /*
194 * Boot time overrides that are not scaled against main memory
195 */
196 void
197 init_param1(void)
198 {
199 #ifndef XEN
200 vm_guest = detect_virtual();
201 #else
202 vm_guest = VM_GUEST_XEN;
203 #endif
204 hz = -1;
205 TUNABLE_INT_FETCH("kern.hz", &hz);
206 if (hz == -1)
207 hz = vm_guest > VM_GUEST_NO ? HZ_VM : HZ;
208 tick = 1000000 / hz;
209
210 #ifdef VM_SWZONE_SIZE_MAX
211 maxswzone = VM_SWZONE_SIZE_MAX;
212 #endif
213 TUNABLE_LONG_FETCH("kern.maxswzone", &maxswzone);
214 #ifdef VM_BCACHE_SIZE_MAX
215 maxbcache = VM_BCACHE_SIZE_MAX;
216 #endif
217 TUNABLE_LONG_FETCH("kern.maxbcache", &maxbcache);
218
219 maxtsiz = MAXTSIZ;
220 TUNABLE_ULONG_FETCH("kern.maxtsiz", &maxtsiz);
221 dfldsiz = DFLDSIZ;
222 TUNABLE_ULONG_FETCH("kern.dfldsiz", &dfldsiz);
223 maxdsiz = MAXDSIZ;
224 TUNABLE_ULONG_FETCH("kern.maxdsiz", &maxdsiz);
225 dflssiz = DFLSSIZ;
226 TUNABLE_ULONG_FETCH("kern.dflssiz", &dflssiz);
227 maxssiz = MAXSSIZ;
228 TUNABLE_ULONG_FETCH("kern.maxssiz", &maxssiz);
229 sgrowsiz = SGROWSIZ;
230 TUNABLE_ULONG_FETCH("kern.sgrowsiz", &sgrowsiz);
231 }
232
233 /*
234 * Boot time overrides that are scaled against main memory
235 */
236 void
237 init_param2(long physpages)
238 {
239
240 /* Base parameters */
241 maxusers = MAXUSERS;
242 TUNABLE_INT_FETCH("kern.maxusers", &maxusers);
243 if (maxusers == 0) {
244 maxusers = physpages / (2 * 1024 * 1024 / PAGE_SIZE);
245 if (maxusers < 32)
246 maxusers = 32;
247 if (maxusers > 384)
248 maxusers = 384;
249 }
250
251 /*
252 * The following can be overridden after boot via sysctl. Note:
253 * unless overriden, these macros are ultimately based on maxusers.
254 */
255 maxproc = NPROC;
256 TUNABLE_INT_FETCH("kern.maxproc", &maxproc);
257 /*
258 * Limit maxproc so that kmap entries cannot be exhausted by
259 * processes.
260 */
261 if (maxproc > (physpages / 12))
262 maxproc = physpages / 12;
263 maxfiles = MAXFILES;
264 TUNABLE_INT_FETCH("kern.maxfiles", &maxfiles);
265 maxprocperuid = (maxproc * 9) / 10;
266 maxfilesperproc = (maxfiles * 9) / 10;
267
268 /*
269 * Cannot be changed after boot.
270 */
271 nbuf = NBUF;
272 TUNABLE_INT_FETCH("kern.nbuf", &nbuf);
273
274 ncallout = 16 + maxproc + maxfiles;
275 TUNABLE_INT_FETCH("kern.ncallout", &ncallout);
276 }
277
278 /*
279 * Boot time overrides that are scaled against the kmem map
280 */
281 void
282 init_param3(long kmempages)
283 {
284
285 /*
286 * The default for maxpipekva is max(5% of the kmem map, 512KB).
287 * See sys_pipe.c for more details.
288 */
289 maxpipekva = (kmempages / 20) * PAGE_SIZE;
290 if (maxpipekva < 512 * 1024)
291 maxpipekva = 512 * 1024;
292 TUNABLE_LONG_FETCH("kern.ipc.maxpipekva", &maxpipekva);
293 }
294
295 /*
296 * Sysctl stringiying handler for kern.vm_guest.
297 */
298 static int
299 sysctl_kern_vm_guest(SYSCTL_HANDLER_ARGS)
300 {
301 return (SYSCTL_OUT(req, vm_guest_sysctl_names[vm_guest],
302 strlen(vm_guest_sysctl_names[vm_guest])));
303 }
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