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 7.2 (Berkeley) 11/30/87 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 */ 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)*NPTEPG) 60 #define USRPTSIZE (32*NPTEPG) 61 62 /* 63 * The size of the clock loop. 64 */ 65 #define LOOPPAGES (maxfree - firstfree) 66 67 /* 68 * The time for a process to be blocked before being very swappable. 69 * This is a number of seconds which the system takes as being a non-trivial 70 * amount of real time. You probably shouldn't change this; 71 * it is used in subtle ways (fractions and multiples of it are, that is, like 72 * half of a ``long time'', almost a long time, etc.) 73 * It is related to human patience and other factors which don't really 74 * change over time. 75 */ 76 #define MAXSLP 20 77 78 /* 79 * A swapped in process is given a small amount of core without being bothered 80 * by the page replacement algorithm. Basically this says that if you are 81 * swapped in you deserve some resources. We protect the last SAFERSS 82 * pages against paging and will just swap you out rather than paging you. 83 * Note that each process has at least UPAGES+CLSIZE pages which are not 84 * paged anyways (this is currently 8+2=10 pages or 5k bytes), so this 85 * number just means a swapped in process is given around 25k bytes. 86 * Just for fun: current memory prices are 4600$ a megabyte on VAX (4/22/81), 87 * so we loan each swapped in process memory worth 100$, or just admit 88 * that we don't consider it worthwhile and swap it out to disk which costs 89 * $30/mb or about $0.75. 90 */ 91 #define SAFERSS 32 /* nominal ``small'' resident set size 92 protected against replacement */ 93 94 /* 95 * DISKRPM is used to estimate the number of paging i/o operations 96 * which one can expect from a single disk controller. 97 */ 98 #define DISKRPM 60 99 100 /* 101 * Klustering constants. Klustering is the gathering 102 * of pages together for pagein/pageout, while clustering 103 * is the treatment of hardware page size as though it were 104 * larger than it really is. 105 * 106 * KLMAX gives maximum cluster size in CLSIZE page (cluster-page) 107 * units. Note that KLMAX*CLSIZE must be <= DMMIN in dmap.h. 108 */ 109 110 #define KLMAX (32/CLSIZE) 111 #define KLSEQL (16/CLSIZE) /* in klust if vadvise(VA_SEQL) */ 112 #define KLIN (8/CLSIZE) /* default data/stack in klust */ 113 #define KLTXT (4/CLSIZE) /* default text in klust */ 114 #define KLOUT (32/CLSIZE) 115 116 /* 117 * KLSDIST is the advance or retard of the fifo reclaim for sequential 118 * processes data space. 119 */ 120 #define KLSDIST 3 /* klusters advance/retard for seq. fifo */ 121 122 /* 123 * Paging thresholds (see vm_sched.c). 124 * Strategy of 1/19/85: 125 * lotsfree is 512k bytes, but at most 1/4 of memory 126 * desfree is 200k bytes, but at most 1/8 of memory 127 * minfree is 64k bytes, but at most 1/2 of desfree 128 */ 129 #define LOTSFREE (512 * 1024) 130 #define LOTSFREEFRACT 4 131 #define DESFREE (200 * 1024) 132 #define DESFREEFRACT 8 133 #define MINFREE (64 * 1024) 134 #define MINFREEFRACT 2 135 136 /* 137 * There are two clock hands, initially separated by HANDSPREAD bytes 138 * (but at most all of user memory). The amount of time to reclaim 139 * a page once the pageout process examines it increases with this 140 * distance and decreases as the scan rate rises. 141 */ 142 #define HANDSPREAD (2 * 1024 * 1024) 143 144 /* 145 * The number of times per second to recompute the desired paging rate 146 * and poke the pagedaemon. 147 */ 148 #define RATETOSCHEDPAGING 4 149 150 /* 151 * Believed threshold (in megabytes) for which interleaved 152 * swapping area is desirable. 153 */ 154 #define LOTSOFMEM 2 155 156 #define mapin(pte, v, pfnum, prot) \ 157 (*(int *)(pte) = (pfnum) | (prot), mtpr(TBIS, v)) 158