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1.1 root 1: /*
2: * Copyright (c) 1982, 1986 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 7.3 (Berkeley) 5/10/90
7: */
8:
9: /*
10: * Machine dependent constants for VAX
11: */
12: /*
13: * USRTEXT is the start of the user text/data space, while USRSTACK
14: * is the top (end) of the user stack. LOWPAGES and HIGHPAGES are
15: * the number of pages from the beginning of the P0 region to the
16: * beginning of the text and from the beginning of the P1 region to the
17: * beginning of the stack respectively.
18: */
19: #define USRTEXT 0
20: #define USRSTACK (0x80000000-UPAGES*NBPG) /* Start of user stack */
21: #define BTOPUSRSTACK (0x400000 - UPAGES) /* btop(USRSTACK) */
22: /* number of ptes per page */
23: #define P1PAGES 0x200000 /* number of pages in P1 region */
24: #define LOWPAGES 0
25: #define HIGHPAGES UPAGES
26:
27: /*
28: * Virtual memory related constants, all in bytes
29: */
30: #ifndef MAXTSIZ
31: #define MAXTSIZ (6*1024*1024) /* max text size */
32: #endif
33: #ifndef DFLDSIZ
34: #define DFLDSIZ (6*1024*1024) /* initial data size limit */
35: #endif
36: #ifndef MAXDSIZ
37: #define MAXDSIZ (16*1024*1024) /* max data size */
38: #endif
39: #ifndef DFLSSIZ
40: #define DFLSSIZ (512*1024) /* initial stack size limit */
41: #endif
42: #ifndef MAXSSIZ
43: #define MAXSSIZ MAXDSIZ /* max stack size */
44: #endif
45:
46: /*
47: * Default sizes of swap allocation chunks (see dmap.h).
48: * The actual values may be changed in vminit() based on MAXDSIZ.
49: * With MAXDSIZ of 16Mb and NDMAP of 38, dmmax will be 1024.
50: * DMMIN should be at least ctod(1) so that vtod() works.
51: * vminit() ensures this.
52: */
53: #define DMMIN 32 /* smallest swap allocation */
54: #define DMMAX 4096 /* largest potential swap allocation */
55: #define DMTEXT 1024 /* swap allocation for text */
56:
57: /*
58: * Sizes of the system and user portions of the system page table.
59: */
60: /* SYSPTSIZE IS SILLY; IT SHOULD BE COMPUTED AT BOOT TIME */
61: #define SYSPTSIZE ((20+MAXUSERS)*NPTEPG)
62: #define USRPTSIZE (32*NPTEPG)
63:
64: /*
65: * PTEs for system V compatible shared memory.
66: * This is basically slop for kmempt which we actually allocate (malloc) from.
67: */
68: #define SHMMAXPGS 1024
69:
70: /*
71: * Boundary at which to place first MAPMEM segment if not explicitly
72: * specified. Should be a power of two. This allows some slop for
73: * the data segment to grow underneath the first mapped segment.
74: */
75: #define MMSEG 0x200000
76:
77: /*
78: * The size of the clock loop.
79: */
80: #define LOOPPAGES (maxfree - firstfree)
81:
82: /*
83: * The time for a process to be blocked before being very swappable.
84: * This is a number of seconds which the system takes as being a non-trivial
85: * amount of real time. You probably shouldn't change this;
86: * it is used in subtle ways (fractions and multiples of it are, that is, like
87: * half of a ``long time'', almost a long time, etc.)
88: * It is related to human patience and other factors which don't really
89: * change over time.
90: */
91: #define MAXSLP 20
92:
93: /*
94: * A swapped in process is given a small amount of core without being bothered
95: * by the page replacement algorithm. Basically this says that if you are
96: * swapped in you deserve some resources. We protect the last SAFERSS
97: * pages against paging and will just swap you out rather than paging you.
98: * Note that each process has at least UPAGES+CLSIZE pages which are not
99: * paged anyways (this is currently 8+2=10 pages or 5k bytes), so this
100: * number just means a swapped in process is given around 25k bytes.
101: * Just for fun: current memory prices are 4600$ a megabyte on VAX (4/22/81),
102: * so we loan each swapped in process memory worth 100$, or just admit
103: * that we don't consider it worthwhile and swap it out to disk which costs
104: * $30/mb or about $0.75.
105: */
106: #define SAFERSS 32 /* nominal ``small'' resident set size
107: protected against replacement */
108:
109: /*
110: * DISKRPM is used to estimate the number of paging i/o operations
111: * which one can expect from a single disk controller.
112: */
113: #define DISKRPM 60
114:
115: /*
116: * Klustering constants. Klustering is the gathering
117: * of pages together for pagein/pageout, while clustering
118: * is the treatment of hardware page size as though it were
119: * larger than it really is.
120: *
121: * KLMAX gives maximum cluster size in CLSIZE page (cluster-page)
122: * units. Note that ctod(KLMAX*CLSIZE) must be <= DMMIN in dmap.h.
123: * ctob(KLMAX) should also be less than MAXPHYS (in vm_swp.c) to
124: * avoid "big push" panics.
125: */
126:
127: #define KLMAX (32/CLSIZE)
128: #define KLSEQL (16/CLSIZE) /* in klust if vadvise(VA_SEQL) */
129: #define KLIN (8/CLSIZE) /* default data/stack in klust */
130: #define KLTXT (4/CLSIZE) /* default text in klust */
131: #define KLOUT (32/CLSIZE)
132:
133: /*
134: * KLSDIST is the advance or retard of the fifo reclaim for sequential
135: * processes data space.
136: */
137: #define KLSDIST 3 /* klusters advance/retard for seq. fifo */
138:
139: /*
140: * Paging thresholds (see vm_sched.c).
141: * Strategy of 1/19/85:
142: * lotsfree is 512k bytes, but at most 1/4 of memory
143: * desfree is 200k bytes, but at most 1/8 of memory
144: * minfree is 64k bytes, but at most 1/2 of desfree
145: */
146: #define LOTSFREE (512 * 1024)
147: #define LOTSFREEFRACT 4
148: #define DESFREE (200 * 1024)
149: #define DESFREEFRACT 8
150: #define MINFREE (64 * 1024)
151: #define MINFREEFRACT 2
152:
153: /*
154: * There are two clock hands, initially separated by HANDSPREAD bytes
155: * (but at most all of user memory). The amount of time to reclaim
156: * a page once the pageout process examines it increases with this
157: * distance and decreases as the scan rate rises.
158: */
159: #define HANDSPREAD (2 * 1024 * 1024)
160:
161: /*
162: * The number of times per second to recompute the desired paging rate
163: * and poke the pagedaemon.
164: */
165: #define RATETOSCHEDPAGING 4
166:
167: /*
168: * Believed threshold (in megabytes) for which interleaved
169: * swapping area is desirable.
170: */
171: #define LOTSOFMEM 2
172:
173: #define mapin(pte, v, pfnum, prot) \
174: (*(int *)(pte) = (pfnum) | (prot), mtpr(TBIS, v))
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