xref: /netbsd-src/sys/arch/i386/include/vmparam.h (revision ae1bfcddc410612bc8c58b807e1830becb69a24c)
1 /*-
2  * Copyright (c) 1990 The Regents of the University of California.
3  * All rights reserved.
4  *
5  * This code is derived from software contributed to Berkeley by
6  * William Jolitz.
7  *
8  * Redistribution and use in source and binary forms, with or without
9  * modification, are permitted provided that the following conditions
10  * are met:
11  * 1. Redistributions of source code must retain the above copyright
12  *    notice, this list of conditions and the following disclaimer.
13  * 2. Redistributions in binary form must reproduce the above copyright
14  *    notice, this list of conditions and the following disclaimer in the
15  *    documentation and/or other materials provided with the distribution.
16  * 3. All advertising materials mentioning features or use of this software
17  *    must display the following acknowledgement:
18  *	This product includes software developed by the University of
19  *	California, Berkeley and its contributors.
20  * 4. Neither the name of the University nor the names of its contributors
21  *    may be used to endorse or promote products derived from this software
22  *    without specific prior written permission.
23  *
24  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
25  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
26  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
27  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
28  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
29  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
30  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
31  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
32  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
33  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
34  * SUCH DAMAGE.
35  *
36  *	from: @(#)vmparam.h	5.9 (Berkeley) 5/12/91
37  *	$Id: vmparam.h,v 1.14 1994/01/16 01:36:07 cgd Exp $
38  */
39 
40 
41 /*
42  * Machine dependent constants for 386.
43  */
44 
45 /*
46  * Virtual address space arrangement. On 386, both user and kernel
47  * share the address space, not unlike the vax.
48  * USRTEXT is the start of the user text/data space, while USRSTACK
49  * is the top (end) of the user stack. Immediately above the user stack
50  * resides the user structure, which is UPAGES long and contains the
51  * kernel stack.
52  *
53  * Immediately after the user structure is the page table map, and then
54  * kernal address space.
55  */
56 #define	USRTEXT		CLBYTES
57 #define	USRSTACK	VM_MAXUSER_ADDRESS
58 
59 /*
60  * Virtual memory related constants, all in bytes
61  */
62 #define	MAXTSIZ		(8*1024*1024)		/* max text size */
63 #ifndef DFLDSIZ
64 #define	DFLDSIZ		(16*1024*1024)		/* initial data size limit */
65 #endif
66 #ifndef MAXDSIZ
67 #define	MAXDSIZ		(256*1024*1024)		/* max data size */
68 #endif
69 #ifndef	DFLSSIZ
70 #define	DFLSSIZ		(512*1024)		/* initial stack size limit */
71 #endif
72 #ifndef	MAXSSIZ
73 #define	MAXSSIZ		(8*1024*1024)		/* max stack size */
74 #endif
75 
76 /*
77  * Default sizes of swap allocation chunks (see dmap.h).
78  * The actual values may be changed in vminit() based on MAXDSIZ.
79  * With MAXDSIZ of 16Mb and NDMAP of 38, dmmax will be 1024.
80  */
81 #define	DMMIN	32			/* smallest swap allocation */
82 #define	DMMAX	4096			/* largest potential swap allocation */
83 #define	DMTEXT	1024			/* swap allocation for text */
84 
85 /*
86  * Size of shared memory map
87  */
88 #ifndef SHMMAXPGS
89 #define SHMMAXPGS	1024
90 #endif
91 
92 /*
93  * Size of User Raw I/O map
94  */
95 #define	USRIOSIZE 	300
96 
97 /*
98  * The time for a process to be blocked before being very swappable.
99  * This is a number of seconds which the system takes as being a non-trivial
100  * amount of real time.  You probably shouldn't change this;
101  * it is used in subtle ways (fractions and multiples of it are, that is, like
102  * half of a ``long time'', almost a long time, etc.)
103  * It is related to human patience and other factors which don't really
104  * change over time.
105  */
106 #define	MAXSLP 		20
107 
108 /*
109  * A swapped in process is given a small amount of core without being bothered
110  * by the page replacement algorithm.  Basically this says that if you are
111  * swapped in you deserve some resources.  We protect the last SAFERSS
112  * pages against paging and will just swap you out rather than paging you.
113  * Note that each process has at least UPAGES+CLSIZE pages which are not
114  * paged anyways (this is currently 8+2=10 pages or 5k bytes), so this
115  * number just means a swapped in process is given around 25k bytes.
116  * Just for fun: current memory prices are 4600$ a megabyte on VAX (4/22/81),
117  * so we loan each swapped in process memory worth 100$, or just admit
118  * that we don't consider it worthwhile and swap it out to disk which costs
119  * $30/mb or about $0.75.
120  * { wfj 6/16/89: Retail AT memory expansion $800/megabyte, loan of $17
121  *   on disk costing $7/mb or $0.18 (in memory still 100:1 in cost!) }
122  */
123 #define	SAFERSS		8		/* nominal ``small'' resident set size
124 					   protected against replacement */
125 
126 /*
127  * Mach derived constants
128  */
129 
130 /* user/kernel map constants */
131 #define VM_MIN_ADDRESS		((vm_offset_t)0)
132 /* PTDPTDI<<PDSHIFT - UPAGES*NBPG */
133 #define VM_MAXUSER_ADDRESS	((vm_offset_t)0xf7bfe000)
134 /* PTDPTDI<<PDSHIFT + PTDPTDI<<PGSHIFT */
135 #define VM_MAX_ADDRESS		((vm_offset_t)0xf7fdf000)
136 /* KPTDI<<PDSHIFT */
137 #define VM_MIN_KERNEL_ADDRESS	((vm_offset_t)0xf8000000)
138 /* APTDPTDI<<PDSHIFT */
139 #define VM_MAX_KERNEL_ADDRESS	((vm_offset_t)0xffc00000)
140 
141 /* virtual sizes (bytes) for various kernel submaps */
142 #define VM_MBUF_SIZE		(NMBCLUSTERS*MCLBYTES)
143 #define VM_KMEM_SIZE		(NKMEMCLUSTERS*CLBYTES)
144 #define VM_PHYS_SIZE		(USRIOSIZE*CLBYTES)
145