xref: /netbsd-src/sys/arch/i386/include/vmparam.h (revision ce0bb6e8d2e560ecacbe865a848624f94498063b)
1 /*	$NetBSD: vmparam.h,v 1.15 1994/10/27 04:16:34 cgd Exp $	*/
2 
3 /*-
4  * Copyright (c) 1990 The Regents of the University of California.
5  * All rights reserved.
6  *
7  * This code is derived from software contributed to Berkeley by
8  * William Jolitz.
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  * 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.
25  *
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
36  * SUCH DAMAGE.
37  *
38  *	@(#)vmparam.h	5.9 (Berkeley) 5/12/91
39  */
40 
41 
42 /*
43  * Machine dependent constants for 386.
44  */
45 
46 /*
47  * Virtual address space arrangement. On 386, both user and kernel
48  * share the address space, not unlike the vax.
49  * USRTEXT is the start of the user text/data space, while USRSTACK
50  * is the top (end) of the user stack. Immediately above the user stack
51  * resides the user structure, which is UPAGES long and contains the
52  * kernel stack.
53  *
54  * Immediately after the user structure is the page table map, and then
55  * kernal address space.
56  */
57 #define	USRTEXT		CLBYTES
58 #define	USRSTACK	VM_MAXUSER_ADDRESS
59 
60 /*
61  * Virtual memory related constants, all in bytes
62  */
63 #define	MAXTSIZ		(8*1024*1024)		/* max text size */
64 #ifndef DFLDSIZ
65 #define	DFLDSIZ		(16*1024*1024)		/* initial data size limit */
66 #endif
67 #ifndef MAXDSIZ
68 #define	MAXDSIZ		(256*1024*1024)		/* max data size */
69 #endif
70 #ifndef	DFLSSIZ
71 #define	DFLSSIZ		(512*1024)		/* initial stack size limit */
72 #endif
73 #ifndef	MAXSSIZ
74 #define	MAXSSIZ		(8*1024*1024)		/* max stack size */
75 #endif
76 
77 /*
78  * Default sizes of swap allocation chunks (see dmap.h).
79  * The actual values may be changed in vminit() based on MAXDSIZ.
80  * With MAXDSIZ of 16Mb and NDMAP of 38, dmmax will be 1024.
81  */
82 #define	DMMIN	32			/* smallest swap allocation */
83 #define	DMMAX	4096			/* largest potential swap allocation */
84 #define	DMTEXT	1024			/* swap allocation for text */
85 
86 /*
87  * Size of shared memory map
88  */
89 #ifndef SHMMAXPGS
90 #define SHMMAXPGS	1024
91 #endif
92 
93 /*
94  * Size of User Raw I/O map
95  */
96 #define	USRIOSIZE 	300
97 
98 /*
99  * The time for a process to be blocked before being very swappable.
100  * This is a number of seconds which the system takes as being a non-trivial
101  * amount of real time.  You probably shouldn't change this;
102  * it is used in subtle ways (fractions and multiples of it are, that is, like
103  * half of a ``long time'', almost a long time, etc.)
104  * It is related to human patience and other factors which don't really
105  * change over time.
106  */
107 #define	MAXSLP 		20
108 
109 /*
110  * A swapped in process is given a small amount of core without being bothered
111  * by the page replacement algorithm.  Basically this says that if you are
112  * swapped in you deserve some resources.  We protect the last SAFERSS
113  * pages against paging and will just swap you out rather than paging you.
114  * Note that each process has at least UPAGES+CLSIZE pages which are not
115  * paged anyways (this is currently 8+2=10 pages or 5k bytes), so this
116  * number just means a swapped in process is given around 25k bytes.
117  * Just for fun: current memory prices are 4600$ a megabyte on VAX (4/22/81),
118  * so we loan each swapped in process memory worth 100$, or just admit
119  * that we don't consider it worthwhile and swap it out to disk which costs
120  * $30/mb or about $0.75.
121  * { wfj 6/16/89: Retail AT memory expansion $800/megabyte, loan of $17
122  *   on disk costing $7/mb or $0.18 (in memory still 100:1 in cost!) }
123  */
124 #define	SAFERSS		8		/* nominal ``small'' resident set size
125 					   protected against replacement */
126 
127 /*
128  * Mach derived constants
129  */
130 
131 /* user/kernel map constants */
132 #define VM_MIN_ADDRESS		((vm_offset_t)0)
133 /* PTDPTDI<<PDSHIFT - UPAGES*NBPG */
134 #define VM_MAXUSER_ADDRESS	((vm_offset_t)0xf7bfe000)
135 /* PTDPTDI<<PDSHIFT + PTDPTDI<<PGSHIFT */
136 #define VM_MAX_ADDRESS		((vm_offset_t)0xf7fdf000)
137 /* KPTDI<<PDSHIFT */
138 #define VM_MIN_KERNEL_ADDRESS	((vm_offset_t)0xf8000000)
139 /* APTDPTDI<<PDSHIFT */
140 #define VM_MAX_KERNEL_ADDRESS	((vm_offset_t)0xffc00000)
141 
142 /* virtual sizes (bytes) for various kernel submaps */
143 #define VM_MBUF_SIZE		(NMBCLUSTERS*MCLBYTES)
144 #define VM_KMEM_SIZE		(NKMEMCLUSTERS*CLBYTES)
145 #define VM_PHYS_SIZE		(USRIOSIZE*CLBYTES)
146