xref: /freebsd/sys/kern/subr_param.c (revision 641a6cfb86023499caafe26a4d821a0b885cf00b)
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_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.h>
52 #include <vm/vm_param.h>
53 #include <vm/pmap.h>
54 
55 /*
56  * System parameter formulae.
57  */
58 
59 #ifndef HZ
60 #  if defined(__mips__) || defined(__arm__)
61 #    define	HZ 100
62 #  else
63 #    define	HZ 1000
64 #  endif
65 #  ifndef HZ_VM
66 #    define	HZ_VM 100
67 #  endif
68 #else
69 #  ifndef HZ_VM
70 #    define	HZ_VM HZ
71 #  endif
72 #endif
73 #define	NPROC (20 + 16 * maxusers)
74 #ifndef NBUF
75 #define NBUF 0
76 #endif
77 #ifndef MAXFILES
78 #define	MAXFILES (maxproc * 2)
79 #endif
80 
81 static int sysctl_kern_vm_guest(SYSCTL_HANDLER_ARGS);
82 
83 int	hz;
84 int	tick;
85 int	maxusers;			/* base tunable */
86 int	maxproc;			/* maximum # of processes */
87 int	maxprocperuid;			/* max # of procs per user */
88 int	maxfiles;			/* sys. wide open files limit */
89 int	maxfilesperproc;		/* per-proc open files limit */
90 int	msgbufsize;			/* size of kernel message buffer */
91 int	ncallout;			/* maximum # of timer events */
92 int	nbuf;
93 int	ngroups_max;			/* max # groups per process */
94 int	nswbuf;
95 long	maxswzone;			/* max swmeta KVA storage */
96 long	maxbcache;			/* max buffer cache KVA storage */
97 long	maxpipekva;			/* Limit on pipe KVA */
98 int 	vm_guest;			/* Running as virtual machine guest? */
99 u_long	maxtsiz;			/* max text size */
100 u_long	dfldsiz;			/* initial data size limit */
101 u_long	maxdsiz;			/* max data size */
102 u_long	dflssiz;			/* initial stack size limit */
103 u_long	maxssiz;			/* max stack size */
104 u_long	sgrowsiz;			/* amount to grow stack */
105 
106 SYSCTL_INT(_kern, OID_AUTO, hz, CTLFLAG_RDTUN, &hz, 0,
107     "Number of clock ticks per second");
108 SYSCTL_INT(_kern, OID_AUTO, ncallout, CTLFLAG_RDTUN, &ncallout, 0,
109     "Number of pre-allocated timer events");
110 SYSCTL_INT(_kern, OID_AUTO, nbuf, CTLFLAG_RDTUN, &nbuf, 0,
111     "Number of buffers in the buffer cache");
112 SYSCTL_INT(_kern, OID_AUTO, nswbuf, CTLFLAG_RDTUN, &nswbuf, 0,
113     "Number of swap buffers");
114 SYSCTL_INT(_kern, OID_AUTO, msgbufsize, CTLFLAG_RDTUN, &msgbufsize, 0,
115     "Size of the kernel message buffer");
116 SYSCTL_LONG(_kern, OID_AUTO, maxswzone, CTLFLAG_RDTUN, &maxswzone, 0,
117     "Maximum memory for swap metadata");
118 SYSCTL_LONG(_kern, OID_AUTO, maxbcache, CTLFLAG_RDTUN, &maxbcache, 0,
119     "Maximum value of vfs.maxbufspace");
120 SYSCTL_ULONG(_kern, OID_AUTO, maxtsiz, CTLFLAG_RDTUN, &maxtsiz, 0,
121     "Maximum text size");
122 SYSCTL_ULONG(_kern, OID_AUTO, dfldsiz, CTLFLAG_RDTUN, &dfldsiz, 0,
123     "Initial data size limit");
124 SYSCTL_ULONG(_kern, OID_AUTO, maxdsiz, CTLFLAG_RDTUN, &maxdsiz, 0,
125     "Maximum data size");
126 SYSCTL_ULONG(_kern, OID_AUTO, dflssiz, CTLFLAG_RDTUN, &dflssiz, 0,
127     "Initial stack size limit");
128 SYSCTL_ULONG(_kern, OID_AUTO, maxssiz, CTLFLAG_RDTUN, &maxssiz, 0,
129     "Maximum stack size");
130 SYSCTL_ULONG(_kern, OID_AUTO, sgrowsiz, CTLFLAG_RDTUN, &sgrowsiz, 0,
131     "Amount to grow stack on a stack fault");
132 SYSCTL_PROC(_kern, OID_AUTO, vm_guest, CTLFLAG_RD | CTLTYPE_STRING,
133     NULL, 0, sysctl_kern_vm_guest, "A",
134     "Virtual machine guest detected? (none|generic|xen)");
135 
136 /*
137  * These have to be allocated somewhere; allocating
138  * them here forces loader errors if this file is omitted
139  * (if they've been externed everywhere else; hah!).
140  */
141 struct	buf *swbuf;
142 
143 /*
144  * The elements of this array are ordered based upon the values of the
145  * corresponding enum VM_GUEST members.
146  */
147 static const char *const vm_guest_sysctl_names[] = {
148 	"none",
149 	"generic",
150 	"xen",
151 	NULL
152 };
153 
154 #ifndef XEN
155 static const char *const vm_bnames[] = {
156 	"QEMU",				/* QEMU */
157 	"Plex86",			/* Plex86 */
158 	"Bochs",			/* Bochs */
159 	"Xen",				/* Xen */
160 	NULL
161 };
162 
163 static const char *const vm_pnames[] = {
164 	"VMware Virtual Platform",	/* VMWare VM */
165 	"Virtual Machine",		/* Microsoft VirtualPC */
166 	"VirtualBox",			/* Sun xVM VirtualBox */
167 	"Parallels Virtual Platform",	/* Parallels VM */
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 	 * The default for maxpipekva is min(1/64 of the kernel address space,
301 	 * max(1/64 of main memory, 512KB)).  See sys_pipe.c for more details.
302 	 */
303 	maxpipekva = (physpages / 64) * PAGE_SIZE;
304 	if (maxpipekva < 512 * 1024)
305 		maxpipekva = 512 * 1024;
306 	if (maxpipekva > (VM_MAX_KERNEL_ADDRESS - VM_MIN_KERNEL_ADDRESS) / 64)
307 		maxpipekva = (VM_MAX_KERNEL_ADDRESS - VM_MIN_KERNEL_ADDRESS) /
308 		    64;
309 	TUNABLE_LONG_FETCH("kern.ipc.maxpipekva", &maxpipekva);
310 }
311 
312 /*
313  * Sysctl stringiying handler for kern.vm_guest.
314  */
315 static int
316 sysctl_kern_vm_guest(SYSCTL_HANDLER_ARGS)
317 {
318 	return (SYSCTL_OUT(req, vm_guest_sysctl_names[vm_guest],
319 	    strlen(vm_guest_sysctl_names[vm_guest])));
320 }
321