subr_param.c revision 240068 
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: head/sys/kern/subr_param.c 240068 2012-09-03 09:26:56Z zont $");
39
40#include "opt_param.h"
41#include "opt_msgbuf.h"
42#include "opt_maxusers.h"
43
44#include <sys/param.h>
45#include <sys/systm.h>
46#include <sys/kernel.h>
47#include <sys/limits.h>
48#include <sys/msgbuf.h>
49#include <sys/sysctl.h>
50#include <sys/proc.h>
51
52#include <vm/vm.h>
53#include <vm/vm_param.h>
54#include <vm/pmap.h>
55
56/*
57 * System parameter formulae.
58 */
59
60#ifndef HZ
61#  if defined(__mips__) || defined(__arm__)
62#    define	HZ 100
63#  else
64#    define	HZ 1000
65#  endif
66#  ifndef HZ_VM
67#    define	HZ_VM 100
68#  endif
69#else
70#  ifndef HZ_VM
71#    define	HZ_VM HZ
72#  endif
73#endif
74#define	NPROC (20 + 16 * maxusers)
75#ifndef NBUF
76#define NBUF 0
77#endif
78#ifndef MAXFILES
79#define	MAXFILES (maxproc * 2)
80#endif
81
82static int sysctl_kern_vm_guest(SYSCTL_HANDLER_ARGS);
83
84int	hz;
85int	tick;
86int	maxusers;			/* base tunable */
87int	maxproc;			/* maximum # of processes */
88int	maxprocperuid;			/* max # of procs per user */
89int	maxfiles;			/* sys. wide open files limit */
90int	maxfilesperproc;		/* per-proc open files limit */
91int	msgbufsize;			/* size of kernel message buffer */
92int	ncallout;			/* maximum # of timer events */
93int	nbuf;
94int	ngroups_max;			/* max # groups per process */
95int	nswbuf;
96pid_t	pid_max = PID_MAX;
97long	maxswzone;			/* max swmeta KVA storage */
98long	maxbcache;			/* max buffer cache KVA storage */
99long	maxpipekva;			/* Limit on pipe KVA */
100int 	vm_guest;			/* Running as virtual machine guest? */
101u_long	maxtsiz;			/* max text size */
102u_long	dfldsiz;			/* initial data size limit */
103u_long	maxdsiz;			/* max data size */
104u_long	dflssiz;			/* initial stack size limit */
105u_long	maxssiz;			/* max stack size */
106u_long	sgrowsiz;			/* amount to grow stack */
107
108SYSCTL_INT(_kern, OID_AUTO, hz, CTLFLAG_RDTUN, &hz, 0,
109    "Number of clock ticks per second");
110SYSCTL_INT(_kern, OID_AUTO, ncallout, CTLFLAG_RDTUN, &ncallout, 0,
111    "Number of pre-allocated timer events");
112SYSCTL_INT(_kern, OID_AUTO, nbuf, CTLFLAG_RDTUN, &nbuf, 0,
113    "Number of buffers in the buffer cache");
114SYSCTL_INT(_kern, OID_AUTO, nswbuf, CTLFLAG_RDTUN, &nswbuf, 0,
115    "Number of swap buffers");
116SYSCTL_INT(_kern, OID_AUTO, msgbufsize, CTLFLAG_RDTUN, &msgbufsize, 0,
117    "Size of the kernel message buffer");
118SYSCTL_LONG(_kern, OID_AUTO, maxswzone, CTLFLAG_RDTUN, &maxswzone, 0,
119    "Maximum memory for swap metadata");
120SYSCTL_LONG(_kern, OID_AUTO, maxbcache, CTLFLAG_RDTUN, &maxbcache, 0,
121    "Maximum value of vfs.maxbufspace");
122SYSCTL_ULONG(_kern, OID_AUTO, maxtsiz, CTLFLAG_RW | CTLFLAG_TUN, &maxtsiz, 0,
123    "Maximum text size");
124SYSCTL_ULONG(_kern, OID_AUTO, dfldsiz, CTLFLAG_RW | CTLFLAG_TUN, &dfldsiz, 0,
125    "Initial data size limit");
126SYSCTL_ULONG(_kern, OID_AUTO, maxdsiz, CTLFLAG_RW | CTLFLAG_TUN, &maxdsiz, 0,
127    "Maximum data size");
128SYSCTL_ULONG(_kern, OID_AUTO, dflssiz, CTLFLAG_RW | CTLFLAG_TUN, &dflssiz, 0,
129    "Initial stack size limit");
130SYSCTL_ULONG(_kern, OID_AUTO, maxssiz, CTLFLAG_RW | CTLFLAG_TUN, &maxssiz, 0,
131    "Maximum stack size");
132SYSCTL_ULONG(_kern, OID_AUTO, sgrowsiz, CTLFLAG_RW | CTLFLAG_TUN, &sgrowsiz, 0,
133    "Amount to grow stack on a stack fault");
134SYSCTL_PROC(_kern, OID_AUTO, vm_guest, CTLFLAG_RD | CTLTYPE_STRING,
135    NULL, 0, sysctl_kern_vm_guest, "A",
136    "Virtual machine guest detected? (none|generic|xen)");
137
138/*
139 * These have to be allocated somewhere; allocating
140 * them here forces loader errors if this file is omitted
141 * (if they've been externed everywhere else; hah!).
142 */
143struct	buf *swbuf;
144
145/*
146 * The elements of this array are ordered based upon the values of the
147 * corresponding enum VM_GUEST members.
148 */
149static const char *const vm_guest_sysctl_names[] = {
150	"none",
151	"generic",
152	"xen",
153	NULL
154};
155
156#ifndef XEN
157static const char *const vm_bnames[] = {
158	"QEMU",				/* QEMU */
159	"Plex86",			/* Plex86 */
160	"Bochs",			/* Bochs */
161	"Xen",				/* Xen */
162	NULL
163};
164
165static const char *const vm_pnames[] = {
166	"VMware Virtual Platform",	/* VMWare VM */
167	"Virtual Machine",		/* Microsoft VirtualPC */
168	"VirtualBox",			/* Sun xVM VirtualBox */
169	"Parallels Virtual Platform",	/* Parallels VM */
170	NULL
171};
172
173
174/*
175 * Detect known Virtual Machine hosts by inspecting the emulated BIOS.
176 */
177static enum VM_GUEST
178detect_virtual(void)
179{
180	char *sysenv;
181	int i;
182
183	sysenv = getenv("smbios.bios.vendor");
184	if (sysenv != NULL) {
185		for (i = 0; vm_bnames[i] != NULL; i++)
186			if (strcmp(sysenv, vm_bnames[i]) == 0) {
187				freeenv(sysenv);
188				return (VM_GUEST_VM);
189			}
190		freeenv(sysenv);
191	}
192	sysenv = getenv("smbios.system.product");
193	if (sysenv != NULL) {
194		for (i = 0; vm_pnames[i] != NULL; i++)
195			if (strcmp(sysenv, vm_pnames[i]) == 0) {
196				freeenv(sysenv);
197				return (VM_GUEST_VM);
198			}
199		freeenv(sysenv);
200	}
201	return (VM_GUEST_NO);
202}
203#endif
204
205/*
206 * Boot time overrides that are not scaled against main memory
207 */
208void
209init_param1(void)
210{
211#ifndef XEN
212	vm_guest = detect_virtual();
213#else
214	vm_guest = VM_GUEST_XEN;
215#endif
216	hz = -1;
217	TUNABLE_INT_FETCH("kern.hz", &hz);
218	if (hz == -1)
219		hz = vm_guest > VM_GUEST_NO ? HZ_VM : HZ;
220	tick = 1000000 / hz;
221
222#ifdef VM_SWZONE_SIZE_MAX
223	maxswzone = VM_SWZONE_SIZE_MAX;
224#endif
225	TUNABLE_LONG_FETCH("kern.maxswzone", &maxswzone);
226#ifdef VM_BCACHE_SIZE_MAX
227	maxbcache = VM_BCACHE_SIZE_MAX;
228#endif
229	TUNABLE_LONG_FETCH("kern.maxbcache", &maxbcache);
230	msgbufsize = MSGBUF_SIZE;
231	TUNABLE_INT_FETCH("kern.msgbufsize", &msgbufsize);
232
233	maxtsiz = MAXTSIZ;
234	TUNABLE_ULONG_FETCH("kern.maxtsiz", &maxtsiz);
235	dfldsiz = DFLDSIZ;
236	TUNABLE_ULONG_FETCH("kern.dfldsiz", &dfldsiz);
237	maxdsiz = MAXDSIZ;
238	TUNABLE_ULONG_FETCH("kern.maxdsiz", &maxdsiz);
239	dflssiz = DFLSSIZ;
240	TUNABLE_ULONG_FETCH("kern.dflssiz", &dflssiz);
241	maxssiz = MAXSSIZ;
242	TUNABLE_ULONG_FETCH("kern.maxssiz", &maxssiz);
243	sgrowsiz = SGROWSIZ;
244	TUNABLE_ULONG_FETCH("kern.sgrowsiz", &sgrowsiz);
245
246	/*
247	 * Let the administrator set {NGROUPS_MAX}, but disallow values
248	 * less than NGROUPS_MAX which would violate POSIX.1-2008 or
249	 * greater than INT_MAX-1 which would result in overflow.
250	 */
251	ngroups_max = NGROUPS_MAX;
252	TUNABLE_INT_FETCH("kern.ngroups", &ngroups_max);
253	if (ngroups_max < NGROUPS_MAX)
254		ngroups_max = NGROUPS_MAX;
255
256	/*
257	 * Only allow to lower the maximal pid.
258	 * Prevent setting up a non-bootable system if pid_max is too low.
259	 */
260	TUNABLE_INT_FETCH("kern.pid_max", &pid_max);
261	if (pid_max > PID_MAX)
262		pid_max = PID_MAX;
263	else if (pid_max < 300)
264		pid_max = 300;
265}
266
267/*
268 * Boot time overrides that are scaled against main memory
269 */
270void
271init_param2(long physpages)
272{
273
274	/* Base parameters */
275	maxusers = MAXUSERS;
276	TUNABLE_INT_FETCH("kern.maxusers", &maxusers);
277	if (maxusers == 0) {
278		maxusers = physpages / (2 * 1024 * 1024 / PAGE_SIZE);
279		if (maxusers < 32)
280			maxusers = 32;
281		if (maxusers > 384)
282			maxusers = 384;
283	}
284
285	/*
286	 * The following can be overridden after boot via sysctl.  Note:
287	 * unless overriden, these macros are ultimately based on maxusers.
288	 */
289	maxproc = NPROC;
290	TUNABLE_INT_FETCH("kern.maxproc", &maxproc);
291	/*
292	 * Limit maxproc so that kmap entries cannot be exhausted by
293	 * processes.
294	 */
295	if (maxproc > (physpages / 12))
296		maxproc = physpages / 12;
297	maxfiles = MAXFILES;
298	TUNABLE_INT_FETCH("kern.maxfiles", &maxfiles);
299	maxprocperuid = (maxproc * 9) / 10;
300	maxfilesperproc = (maxfiles * 9) / 10;
301
302	/*
303	 * Cannot be changed after boot.
304	 */
305	nbuf = NBUF;
306	TUNABLE_INT_FETCH("kern.nbuf", &nbuf);
307
308	ncallout = 16 + maxproc + maxfiles;
309	TUNABLE_INT_FETCH("kern.ncallout", &ncallout);
310
311	/*
312	 * The default for maxpipekva is min(1/64 of the kernel address space,
313	 * max(1/64 of main memory, 512KB)).  See sys_pipe.c for more details.
314	 */
315	maxpipekva = (physpages / 64) * PAGE_SIZE;
316	if (maxpipekva < 512 * 1024)
317		maxpipekva = 512 * 1024;
318	if (maxpipekva > (VM_MAX_KERNEL_ADDRESS - VM_MIN_KERNEL_ADDRESS) / 64)
319		maxpipekva = (VM_MAX_KERNEL_ADDRESS - VM_MIN_KERNEL_ADDRESS) /
320		    64;
321	TUNABLE_LONG_FETCH("kern.ipc.maxpipekva", &maxpipekva);
322}
323
324/*
325 * Sysctl stringiying handler for kern.vm_guest.
326 */
327static int
328sysctl_kern_vm_guest(SYSCTL_HANDLER_ARGS)
329{
330	return (SYSCTL_OUT(req, vm_guest_sysctl_names[vm_guest],
331	    strlen(vm_guest_sysctl_names[vm_guest])));
332}
333