2 * Copyright (c) 1982, 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.
10 * Redistribution and use in source and binary forms, with or without
11 * modification, are permitted provided that the following conditions
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 * 3. All advertising materials mentioning features or use of this software
19 * must display the following acknowledgement:
20 * This product includes software developed by the University of
21 * California, Berkeley and its contributors.
22 * 4. Neither the name of the University nor the names of its contributors
23 * may be used to endorse or promote products derived from this software
24 * without specific prior written permission.
26 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
27 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
28 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
29 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
30 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
31 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
32 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
33 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
34 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
35 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
38 * @(#)param.h 8.3 (Berkeley) 4/4/95
39 * $Id: param.h,v 1.34 1998/07/06 16:07:43 eivind Exp $
45 #define BSD 199506 /* System version (year & month). */
48 #undef __FreeBSD_version
49 #define __FreeBSD_version 300003 /* Master, propagated to newvers */
56 #include <sys/types.h>
60 * Machine-independent constants (some used in following include files).
61 * Redefined constants are from POSIX 1003.1 limits file.
63 * MAXCOMLEN should be >= sizeof(ac_comm) (see <acct.h>)
64 * MAXLOGNAME should be == UT_NAMESIZE+1 (see <utmp.h>)
66 #include <sys/syslimits.h>
68 #define MAXCOMLEN 16 /* max command name remembered */
69 #define MAXINTERP 32 /* max interpreter file name length */
70 #define MAXLOGNAME 17 /* max login name length (incl. NUL) */
71 #define MAXUPRC CHILD_MAX /* max simultaneous processes */
72 #define NCARGS ARG_MAX /* max bytes for an exec function */
73 #define NGROUPS NGROUPS_MAX /* max number groups */
74 #define NOFILE OPEN_MAX /* max open files per process */
75 #define NOGROUP 65535 /* marker for empty group set member */
76 #define MAXHOSTNAMELEN 256 /* max hostname size */
78 /* More types and definitions used throughout the kernel. */
80 #include <sys/cdefs.h>
81 #include <sys/errno.h>
90 #include <sys/signal.h>
93 /* Machine type dependent parameters. */
94 #include <machine/param.h>
96 #include <machine/limits.h>
100 * Priorities. Note that with 32 run queues, differences less than 4 are
108 #define PZERO 22 /* No longer magic, shouldn't be here. XXX */
115 #define MAXPRI 127 /* Priorities range from 0 through MAXPRI. */
117 #define PRIMASK 0x0ff
118 #define PCATCH 0x100 /* OR'd with pri for tsleep to check signals */
120 #define NZERO 0 /* default "nice" */
122 #define NBPW sizeof(int) /* number of bytes per word (integer) */
124 #define CMASK 022 /* default file mask: S_IWGRP|S_IWOTH */
125 #define NODEV (dev_t)(-1) /* non-existent device */
128 * Clustering of hardware pages on machines with ridiculously small
129 * page sizes is done here. The paging subsystem deals with units of
130 * CLSIZE pte's describing PAGE_SIZE (from machine/machparam.h) pages each.
133 #define CLBYTES (CLSIZE*PAGE_SIZE)
136 #define CBLOCK 128 /* Clist block size, must be a power of 2. */
137 #define CBQSIZE (CBLOCK/NBBY) /* Quote bytes/cblock - can do better. */
138 /* Data chars/clist. */
139 #define CBSIZE (CBLOCK - sizeof(struct cblock *) - CBQSIZE)
140 #define CROUND (CBLOCK - 1) /* Clist rounding. */
143 * File system parameters and macros.
145 * The file system is made out of blocks of at most MAXBSIZE units, with
146 * smaller units (fragments) only in the last direct block. MAXBSIZE
147 * primarily determines the size of buffers in the buffer pool. It may be
148 * made larger without any effect on existing file systems; however making
149 * it smaller make make some file systems unmountable. Also, MAXBSIZE
150 * must be less than MAXPHYS!!! DFLTBSIZE is the average amount of
151 * memory allocated by vfs_bio per nbuf. BKVASIZE is the average amount
152 * of kernel virtual space allocated per nbuf. BKVASIZE should be >=
153 * DFLTBSIZE. If it is significantly bigger than DFLTBSIZE, then
154 * kva fragmentation causes fewer performance problems.
156 #define MAXBSIZE 65536
157 #define BKVASIZE 8192
158 #define DFLTBSIZE 4096
162 * MAXPATHLEN defines the longest permissible path length after expanding
163 * symbolic links. It is used to allocate a temporary buffer from the buffer
164 * pool in which to do the name expansion, hence should be a power of two,
165 * and must be less than or equal to MAXBSIZE. MAXSYMLINKS defines the
166 * maximum number of symbolic links that may be expanded in a path name.
167 * It should be set high enough to allow all legitimate uses, but halt
168 * infinite loops reasonably quickly.
170 #define MAXPATHLEN PATH_MAX
171 #define MAXSYMLINKS 32
173 /* Bit map related macros. */
174 #define setbit(a,i) ((a)[(i)/NBBY] |= 1<<((i)%NBBY))
175 #define clrbit(a,i) ((a)[(i)/NBBY] &= ~(1<<((i)%NBBY)))
176 #define isset(a,i) ((a)[(i)/NBBY] & (1<<((i)%NBBY)))
177 #define isclr(a,i) (((a)[(i)/NBBY] & (1<<((i)%NBBY))) == 0)
179 /* Macros for counting and rounding. */
181 #define howmany(x, y) (((x)+((y)-1))/(y))
183 #define rounddown(x, y) (((x)/(y))*(y))
184 #define roundup(x, y) ((((x)+((y)-1))/(y))*(y)) /* to any y */
185 #define roundup2(x, y) (((x)+((y)-1))&(~((y)-1))) /* if y is powers of two */
186 #define powerof2(x) ((((x)-1)&(x))==0)
188 /* Macros for min/max. */
190 #define MIN(a,b) (((a)<(b))?(a):(b))
191 #define MAX(a,b) (((a)>(b))?(a):(b))
195 * Constants for setting the parameters of the kernel memory allocator.
197 * 2 ** MINBUCKET is the smallest unit of memory that will be
198 * allocated. It must be at least large enough to hold a pointer.
200 * Units of memory less or equal to MAXALLOCSAVE will permanently
201 * allocate physical memory; requests for these size pieces of
202 * memory are quite fast. Allocations greater than MAXALLOCSAVE must
203 * always allocate and free physical memory; requests for these
204 * size allocations should be done infrequently as they will be slow.
206 * Constraints: PAGE_SIZE <= MAXALLOCSAVE <= 2 ** (MINBUCKET + 14), and
207 * MAXALLOCSIZE must be a power of two.
209 #if defined(__alpha__)
210 #define MINBUCKET 5 /* 5 => min allocation of 32 bytes */
212 #define MINBUCKET 4 /* 4 => min allocation of 16 bytes */
214 #define MAXALLOCSAVE (2 * PAGE_SIZE)
217 * Scale factor for scaled integers used to count %cpu time and load avgs.
219 * The number of CPU `tick's that map to a unique `%age' can be expressed
220 * by the formula (1 / (2 ^ (FSHIFT - 11))). The maximum load average that
221 * can be calculated (assuming 32 bits) can be closely approximated using
222 * the formula (2 ^ (2 * (16 - FSHIFT))) for (FSHIFT < 15).
224 * For the scheduler to maintain a 1:1 mapping of CPU `tick' to `%age',
225 * FSHIFT must be at least 11; this gives us a maximum load avg of ~1024.
227 #define FSHIFT 11 /* bits to right of fixed binary point */
228 #define FSCALE (1<<FSHIFT)
230 #endif /* _SYS_PARAM_H_ */