1 /*- 2 * Copyright (c) 1988 The Regents of the University of California. 3 * All rights reserved. 4 * 5 * This code is derived from software contributed to Berkeley by 6 * Computer Consoles Inc. 7 * 8 * %sccs.include.proprietary.c% 9 * 10 * @(#)vmparam.h 7.3 (Berkeley) 05/08/91 11 */ 12 13 /*- 14 * Machine dependent constants for tahoe. 15 */ 16 17 /* 18 * USRTEXT is the start of the user text/data space, while USRSTACK 19 * is the top (end) of the user stack. LOWPAGES and HIGHPAGES are 20 * the number of pages from the beginning of the P0 region to the 21 * beginning of the text and from the beginning of the P2 region to the 22 * beginning of the stack respectively. 23 */ 24 #define USRTEXT 0 25 #define USRSTACK (0xc0000000-UPAGES*NBPG) /* Start of user stack */ 26 #define BTOPUSRSTACK (0x300000 - UPAGES) /* btop(USRSTACK) */ 27 #define P2PAGES 0x100000 /* number of pages in P2 region */ 28 #define LOWPAGES 0 29 #define HIGHPAGES UPAGES 30 31 /* 32 * Virtual memory related constants, all in bytes 33 */ 34 #define MAXTSIZ (6*1024*1024) /* max text size */ 35 #ifndef DFLDSIZ 36 #define DFLDSIZ (6*1024*1024) /* initial data size limit */ 37 #endif 38 #ifndef MAXDSIZ 39 #define MAXDSIZ (32*1024*1024) /* max data size */ 40 #endif 41 #ifndef DFLSSIZ 42 #define DFLSSIZ (512*1024) /* initial stack size limit */ 43 #endif 44 #ifndef MAXSSIZ 45 #define MAXSSIZ MAXDSIZ /* max stack size */ 46 #endif 47 48 /* 49 * Default sizes of swap allocation chunks (see dmap.h). 50 * The actual values may be changed in vminit() based on MAXDSIZ. 51 * With MAXDSIZ of 16Mb and NDMAP of 38, dmmax will be 1024. 52 * DMMIN should be at least ctod(1) so that vtod() works. 53 * vminit() ensures this. 54 */ 55 #define DMMIN 32 /* smallest swap allocation */ 56 #define DMMAX 4096 /* largest potential swap allocation */ 57 #define DMTEXT 1024 /* swap allocation for text */ 58 59 /* 60 * Sizes of the system and user portions of the system page table. 61 */ 62 /* SYSPTSIZE IS SILLY; IT SHOULD BE COMPUTED AT BOOT TIME */ 63 #define SYSPTSIZE ((20+MAXUSERS/2)*NPTEPG) 64 #define USRPTSIZE (4*NPTEPG) 65 66 /* 67 * PTEs for system V compatible shared memory. 68 * This is basically slop for kmempt which we actually allocate (malloc) from. 69 */ 70 #define SHMMAXPGS 512 71 72 /* 73 * Boundary at which to place first MAPMEM segment if not explicitly 74 * specified. Should be a power of two. This allows some slop for 75 * the data segment to grow underneath the first mapped segment. 76 */ 77 #define MMSEG 0x200000 78 79 /* 80 * The size of the clock loop. 81 */ 82 #define LOOPPAGES (maxfree - firstfree) 83 84 /* 85 * The time for a process to be blocked before being very swappable. 86 * This is a number of seconds which the system takes as being a non-trivial 87 * amount of real time. You probably shouldn't change this; 88 * it is used in subtle ways (fractions and multiples of it are, that is, like 89 * half of a ``long time'', almost a long time, etc.) 90 * It is related to human patience and other factors which don't really 91 * change over time. 92 */ 93 #define MAXSLP 20 94 95 /* 96 * A swapped in process is given a small amount of core without being bothered 97 * by the page replacement algorithm. Basically this says that if you are 98 * swapped in you deserve some resources. We protect the last SAFERSS 99 * pages against paging and will just swap you out rather than paging you. 100 * Note that each process has at least UPAGES+CLSIZE pages which are not 101 * paged anyways (this is currently 8+2=10 pages or 5k bytes), so this 102 * number just means a swapped in process is given around 25k bytes. 103 * Just for fun: current memory prices are 4600$ a megabyte on VAX (4/22/81), 104 * so we loan each swapped in process memory worth 100$, or just admit 105 * that we don't consider it worthwhile and swap it out to disk which costs 106 * $30/mb or about $0.75. 107 */ 108 #define SAFERSS 32 /* nominal ``small'' resident set size 109 protected against replacement */ 110 111 /* 112 * DISKRPM is used to estimate the number of paging i/o operations 113 * which one can expect from a single disk controller. 114 */ 115 #define DISKRPM 60 116 117 /* 118 * Klustering constants. Klustering is the gathering 119 * of pages together for pagein/pageout, while clustering 120 * is the treatment of hardware page size as though it were 121 * larger than it really is. 122 * 123 * KLMAX gives maximum cluster size in CLSIZE page (cluster-page) 124 * units. Note that ctod(KLMAX*CLSIZE) must be <= DMMIN in dmap.h. 125 * ctob(KLMAX) should also be less than MAXPHYS (in vm_swp.c) to 126 * avoid "big push" panics. 127 */ 128 129 #define KLMAX (32/CLSIZE) 130 #define KLSEQL (16/CLSIZE) /* in klust if vadvise(VA_SEQL) */ 131 #define KLIN (8/CLSIZE) /* default data/stack in klust */ 132 #define KLTXT (4/CLSIZE) /* default text in klust */ 133 #define KLOUT (32/CLSIZE) 134 135 /* 136 * KLSDIST is the advance or retard of the fifo reclaim for sequential 137 * processes data space. 138 */ 139 #define KLSDIST 3 /* klusters advance/retard for seq. fifo */ 140 141 /* 142 * Paging thresholds (see vm_sched.c). 143 * Strategy of 1/19/85: 144 * lotsfree is 512k bytes, but at most 1/4 of memory 145 * desfree is 200k bytes, but at most 1/8 of memory 146 * minfree is 64k bytes, but at most 1/2 of desfree 147 */ 148 #define LOTSFREE (512 * 1024) 149 #define LOTSFREEFRACT 4 150 #define DESFREE (200 * 1024) 151 #define DESFREEFRACT 8 152 #define MINFREE (64 * 1024) 153 #define MINFREEFRACT 2 154 155 /* 156 * There are two clock hands, initially separated by HANDSPREAD bytes 157 * (but at most all of user memory). The amount of time to reclaim 158 * a page once the pageout process examines it increases with this 159 * distance and decreases as the scan rate rises. 160 */ 161 #define HANDSPREAD (2 * 1024 * 1024) 162 163 /* 164 * The number of times per second to recompute the desired paging rate 165 * and poke the pagedaemon. 166 */ 167 #define RATETOSCHEDPAGING 4 168 169 /* 170 * Believed threshold (in megabytes) for which interleaved 171 * swapping area is desirable. 172 */ 173 #define LOTSOFMEM 2 174 175 #define mapin(pte, v, pfnum, prot) \ 176 (*(int *)(pte) = (pfnum) | (prot), mtpr(TBIS, v)) 177 178 /* 179 * Invalidate a cluster (optimized here for standard CLSIZE). 180 */ 181 #if CLSIZE == 1 182 #define tbiscl(v) mtpr(TBIS, ptob(v)) 183 #endif 184