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1.1 root 1: /*
2: * Copyright (c) 1988 Regents of the University of California.
3: * All rights reserved. The Berkeley software License Agreement
4: * specifies the terms and conditions for redistribution.
5: *
6: * @(#)vmparam.h 7.1 (Berkeley) 5/21/88
7: */
8:
9: /*
10: * Machine dependent constants for tahoe.
11: */
12:
13: /*
14: * USRTEXT is the start of the user text/data space, while USRSTACK
15: * is the top (end) of the user stack. LOWPAGES and HIGHPAGES are
16: * the number of pages from the beginning of the P0 region to the
17: * beginning of the text and from the beginning of the P2 region to the
18: * beginning of the stack respectively.
19: */
20: #define USRTEXT 0
21: #define USRSTACK (0xc0000000-UPAGES*NBPG) /* Start of user stack */
22: #define BTOPUSRSTACK (0x300000 - UPAGES) /* btop(USRSTACK) */
23: #define P2PAGES 0x100000 /* number of pages in P2 region */
24: #define LOWPAGES 0
25: #define HIGHPAGES UPAGES
26:
27: /*
28: * Virtual memory related constants, all in bytes
29: */
30: #define MAXTSIZ (6*1024*1024) /* max text size */
31: #ifndef DFLDSIZ
32: #define DFLDSIZ (6*1024*1024) /* initial data size limit */
33: #endif
34: #ifndef MAXDSIZ
35: #define MAXDSIZ (32*1024*1024) /* max data size */
36: #endif
37: #ifndef DFLSSIZ
38: #define DFLSSIZ (512*1024) /* initial stack size limit */
39: #endif
40: #ifndef MAXSSIZ
41: #define MAXSSIZ MAXDSIZ /* max stack size */
42: #endif
43:
44: /*
45: * Default sizes of swap allocation chunks (see dmap.h).
46: * The actual values may be changed in vminit() based on MAXDSIZ.
47: * With MAXDSIZ of 16Mb and NDMAP of 38, dmmax will be 1024.
48: */
49: #define DMMIN 32 /* smallest swap allocation */
50: #define DMMAX 4096 /* largest potential swap allocation */
51: #define DMTEXT 1024 /* swap allocation for text */
52:
53: /*
54: * Sizes of the system and user portions of the system page table.
55: */
56: /* SYSPTSIZE IS SILLY; IT SHOULD BE COMPUTED AT BOOT TIME */
57: #define SYSPTSIZE ((20+MAXUSERS/2)*NPTEPG)
58: #define USRPTSIZE (4*NPTEPG)
59:
60: /*
61: * The size of the clock loop.
62: */
63: #define LOOPPAGES (maxfree - firstfree)
64:
65: /*
66: * The time for a process to be blocked before being very swappable.
67: * This is a number of seconds which the system takes as being a non-trivial
68: * amount of real time. You probably shouldn't change this;
69: * it is used in subtle ways (fractions and multiples of it are, that is, like
70: * half of a ``long time'', almost a long time, etc.)
71: * It is related to human patience and other factors which don't really
72: * change over time.
73: */
74: #define MAXSLP 20
75:
76: /*
77: * A swapped in process is given a small amount of core without being bothered
78: * by the page replacement algorithm. Basically this says that if you are
79: * swapped in you deserve some resources. We protect the last SAFERSS
80: * pages against paging and will just swap you out rather than paging you.
81: * Note that each process has at least UPAGES+CLSIZE pages which are not
82: * paged anyways (this is currently 8+2=10 pages or 5k bytes), so this
83: * number just means a swapped in process is given around 25k bytes.
84: * Just for fun: current memory prices are 4600$ a megabyte on VAX (4/22/81),
85: * so we loan each swapped in process memory worth 100$, or just admit
86: * that we don't consider it worthwhile and swap it out to disk which costs
87: * $30/mb or about $0.75.
88: */
89: #define SAFERSS 32 /* nominal ``small'' resident set size
90: protected against replacement */
91:
92: /*
93: * DISKRPM is used to estimate the number of paging i/o operations
94: * which one can expect from a single disk controller.
95: */
96: #define DISKRPM 60
97:
98: /*
99: * Klustering constants. Klustering is the gathering
100: * of pages together for pagein/pageout, while clustering
101: * is the treatment of hardware page size as though it were
102: * larger than it really is.
103: *
104: * KLMAX gives maximum cluster size in CLSIZE page (cluster-page)
105: * units. Note that KLMAX*CLSIZE must be <= DMMIN in dmap.h.
106: */
107:
108: #define KLMAX (32/CLSIZE)
109: #define KLSEQL (16/CLSIZE) /* in klust if vadvise(VA_SEQL) */
110: #define KLIN (8/CLSIZE) /* default data/stack in klust */
111: #define KLTXT (4/CLSIZE) /* default text in klust */
112: #define KLOUT (32/CLSIZE)
113:
114: /*
115: * KLSDIST is the advance or retard of the fifo reclaim for sequential
116: * processes data space.
117: */
118: #define KLSDIST 3 /* klusters advance/retard for seq. fifo */
119:
120: /*
121: * Paging thresholds (see vm_sched.c).
122: * Strategy of 1/19/85:
123: * lotsfree is 512k bytes, but at most 1/4 of memory
124: * desfree is 200k bytes, but at most 1/8 of memory
125: * minfree is 64k bytes, but at most 1/2 of desfree
126: */
127: #define LOTSFREE (512 * 1024)
128: #define LOTSFREEFRACT 4
129: #define DESFREE (200 * 1024)
130: #define DESFREEFRACT 8
131: #define MINFREE (64 * 1024)
132: #define MINFREEFRACT 2
133:
134: /*
135: * There are two clock hands, initially separated by HANDSPREAD bytes
136: * (but at most all of user memory). The amount of time to reclaim
137: * a page once the pageout process examines it increases with this
138: * distance and decreases as the scan rate rises.
139: */
140: #define HANDSPREAD (2 * 1024 * 1024)
141:
142: /*
143: * The number of times per second to recompute the desired paging rate
144: * and poke the pagedaemon.
145: */
146: #define RATETOSCHEDPAGING 4
147:
148: /*
149: * Believed threshold (in megabytes) for which interleaved
150: * swapping area is desirable.
151: */
152: #define LOTSOFMEM 2
153:
154: #define mapin(pte, v, pfnum, prot) \
155: (*(int *)(pte) = (pfnum) | (prot), mtpr(TBIS, v))
156:
157: /*
158: * Invalidate a cluster (optimized here for standard CLSIZE).
159: */
160: #if CLSIZE == 1
161: #define tbiscl(v) mtpr(TBIS, ptob(v))
162: #endif
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