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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 7.2 (Berkeley) 5/10/90
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: * DMMIN should be at least ctod(1) so that vtod() works.
49: * vminit() ensures this.
50: */
51: #define DMMIN 32 /* smallest swap allocation */
52: #define DMMAX 4096 /* largest potential swap allocation */
53: #define DMTEXT 1024 /* swap allocation for text */
54:
55: /*
56: * Sizes of the system and user portions of the system page table.
57: */
58: /* SYSPTSIZE IS SILLY; IT SHOULD BE COMPUTED AT BOOT TIME */
59: #define SYSPTSIZE ((20+MAXUSERS/2)*NPTEPG)
60: #define USRPTSIZE (4*NPTEPG)
61:
62: /*
63: * PTEs for system V compatible shared memory.
64: * This is basically slop for kmempt which we actually allocate (malloc) from.
65: */
66: #define SHMMAXPGS 512
67:
68: /*
69: * Boundary at which to place first MAPMEM segment if not explicitly
70: * specified. Should be a power of two. This allows some slop for
71: * the data segment to grow underneath the first mapped segment.
72: */
73: #define MMSEG 0x200000
74:
75: /*
76: * The size of the clock loop.
77: */
78: #define LOOPPAGES (maxfree - firstfree)
79:
80: /*
81: * The time for a process to be blocked before being very swappable.
82: * This is a number of seconds which the system takes as being a non-trivial
83: * amount of real time. You probably shouldn't change this;
84: * it is used in subtle ways (fractions and multiples of it are, that is, like
85: * half of a ``long time'', almost a long time, etc.)
86: * It is related to human patience and other factors which don't really
87: * change over time.
88: */
89: #define MAXSLP 20
90:
91: /*
92: * A swapped in process is given a small amount of core without being bothered
93: * by the page replacement algorithm. Basically this says that if you are
94: * swapped in you deserve some resources. We protect the last SAFERSS
95: * pages against paging and will just swap you out rather than paging you.
96: * Note that each process has at least UPAGES+CLSIZE pages which are not
97: * paged anyways (this is currently 8+2=10 pages or 5k bytes), so this
98: * number just means a swapped in process is given around 25k bytes.
99: * Just for fun: current memory prices are 4600$ a megabyte on VAX (4/22/81),
100: * so we loan each swapped in process memory worth 100$, or just admit
101: * that we don't consider it worthwhile and swap it out to disk which costs
102: * $30/mb or about $0.75.
103: */
104: #define SAFERSS 32 /* nominal ``small'' resident set size
105: protected against replacement */
106:
107: /*
108: * DISKRPM is used to estimate the number of paging i/o operations
109: * which one can expect from a single disk controller.
110: */
111: #define DISKRPM 60
112:
113: /*
114: * Klustering constants. Klustering is the gathering
115: * of pages together for pagein/pageout, while clustering
116: * is the treatment of hardware page size as though it were
117: * larger than it really is.
118: *
119: * KLMAX gives maximum cluster size in CLSIZE page (cluster-page)
120: * units. Note that ctod(KLMAX*CLSIZE) must be <= DMMIN in dmap.h.
121: * ctob(KLMAX) should also be less than MAXPHYS (in vm_swp.c) to
122: * avoid "big push" panics.
123: */
124:
125: #define KLMAX (32/CLSIZE)
126: #define KLSEQL (16/CLSIZE) /* in klust if vadvise(VA_SEQL) */
127: #define KLIN (8/CLSIZE) /* default data/stack in klust */
128: #define KLTXT (4/CLSIZE) /* default text in klust */
129: #define KLOUT (32/CLSIZE)
130:
131: /*
132: * KLSDIST is the advance or retard of the fifo reclaim for sequential
133: * processes data space.
134: */
135: #define KLSDIST 3 /* klusters advance/retard for seq. fifo */
136:
137: /*
138: * Paging thresholds (see vm_sched.c).
139: * Strategy of 1/19/85:
140: * lotsfree is 512k bytes, but at most 1/4 of memory
141: * desfree is 200k bytes, but at most 1/8 of memory
142: * minfree is 64k bytes, but at most 1/2 of desfree
143: */
144: #define LOTSFREE (512 * 1024)
145: #define LOTSFREEFRACT 4
146: #define DESFREE (200 * 1024)
147: #define DESFREEFRACT 8
148: #define MINFREE (64 * 1024)
149: #define MINFREEFRACT 2
150:
151: /*
152: * There are two clock hands, initially separated by HANDSPREAD bytes
153: * (but at most all of user memory). The amount of time to reclaim
154: * a page once the pageout process examines it increases with this
155: * distance and decreases as the scan rate rises.
156: */
157: #define HANDSPREAD (2 * 1024 * 1024)
158:
159: /*
160: * The number of times per second to recompute the desired paging rate
161: * and poke the pagedaemon.
162: */
163: #define RATETOSCHEDPAGING 4
164:
165: /*
166: * Believed threshold (in megabytes) for which interleaved
167: * swapping area is desirable.
168: */
169: #define LOTSOFMEM 2
170:
171: #define mapin(pte, v, pfnum, prot) \
172: (*(int *)(pte) = (pfnum) | (prot), mtpr(TBIS, v))
173:
174: /*
175: * Invalidate a cluster (optimized here for standard CLSIZE).
176: */
177: #if CLSIZE == 1
178: #define tbiscl(v) mtpr(TBIS, ptob(v))
179: #endif
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