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) 05/10/90 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)) 175