1 /* vmparam.h 4.5 83/06/29 */ 2 3 /* 4 * Machine dependent constants for VAX 5 */ 6 /* 7 * USRTEXT is the start of the user text/data space, while USRSTACK 8 * is the top (end) of the user stack. LOWPAGES and HIGHPAGES are 9 * the number of pages from the beginning of the P0 region to the 10 * beginning of the text and from the beginning of the P1 region to the 11 * beginning of the stack respectively. 12 */ 13 /* number of ptes per page */ 14 #define USRTEXT 0 15 #define USRSTACK (0x80000000-UPAGES*NBPG) 16 /* Start of user stack */ 17 #define P1PAGES 0x200000 /* number of pages in P1 region */ 18 #define LOWPAGES 0 19 #define HIGHPAGES UPAGES 20 21 /* 22 * Virtual memory related constants 23 */ 24 #define SLOP 32 25 #define MAXTSIZ (6*2048-SLOP) /* max text size (clicks) */ 26 #ifndef MAXDSIZ 27 #define MAXDSIZ (12*1024-32-SLOP) /* max data size (clicks) */ 28 #endif 29 #define MAXSSIZ (12*1024-32-SLOP) /* max stack size (clicks) */ 30 31 /* 32 * Sizes of the system and user portions of the system page table. 33 */ 34 /* SYSPTSIZE IS SILLY; IT SHOULD BE COMPUTED AT BOOT TIME */ 35 #define SYSPTSIZE ((20+MAXUSERS)*NPTEPG) 36 #define USRPTSIZE (8*NPTEPG) 37 38 /* 39 * The size of the clock loop. 40 */ 41 #define LOOPPAGES (maxfree - firstfree) 42 43 /* 44 * The time for a process to be blocked before being very swappable. 45 * This is a number of seconds which the system takes as being a non-trivial 46 * amount of real time. You probably shouldn't change this; 47 * it is used in subtle ways (fractions and multiples of it are, that is, like 48 * half of a ``long time'', almost a long time, etc.) 49 * It is related to human patience and other factors which don't really 50 * change over time. 51 */ 52 #define MAXSLP 20 53 54 /* 55 * A swapped in process is given a small amount of core without being bothered 56 * by the page replacement algorithm. Basically this says that if you are 57 * swapped in you deserve some resources. We protect the last SAFERSS 58 * pages against paging and will just swap you out rather than paging you. 59 * Note that each process has at least UPAGES+CLSIZE pages which are not 60 * paged anyways (this is currently 8+2=10 pages or 5k bytes), so this 61 * number just means a swapped in process is given around 25k bytes. 62 * Just for fun: current memory prices are 4600$ a megabyte on VAX (4/22/81), 63 * so we loan each swapped in process memory worth 100$, or just admit 64 * that we don't consider it worthwhile and swap it out to disk which costs 65 * $30/mb or about $0.75. 66 */ 67 #define SAFERSS 32 /* nominal ``small'' resident set size 68 protected against replacement */ 69 70 /* 71 * DISKRPM is used to estimate the number of paging i/o operations 72 * which one can expect from a single disk controller. 73 */ 74 #define DISKRPM 60 75 76 /* 77 * Klustering constants. Klustering is the gathering 78 * of pages together for pagein/pageout, while clustering 79 * is the treatment of hardware page size as though it were 80 * larger than it really is. 81 * 82 * KLMAX gives maximum cluster size in CLSIZE page (cluster-page) 83 * units. Note that KLMAX*CLSIZE must be <= DMMIN in dmap.h. 84 */ 85 86 #define KLMAX (32/CLSIZE) 87 #define KLSEQL (16/CLSIZE) /* in klust if vadvise(VA_SEQL) */ 88 #define KLIN (8/CLSIZE) /* default data/stack in klust */ 89 #define KLTXT (4/CLSIZE) /* default text in klust */ 90 #define KLOUT (32/CLSIZE) 91 92 /* 93 * KLSDIST is the advance or retard of the fifo reclaim for sequential 94 * processes data space. 95 */ 96 #define KLSDIST 3 /* klusters advance/retard for seq. fifo */ 97 98 /* 99 * Paging thresholds (see vm_sched.c). 100 * Strategy of 4/22/81: 101 * lotsfree is 1/4 of memory free. 102 * desfree is 200k bytes, but at most 1/8 of memory 103 * minfree is 64k bytes, but at most 1/2 of desfree 104 */ 105 #define LOTSFREEFRACT 4 106 #define DESFREE (200 * 1024) 107 #define DESFREEFRACT 8 108 #define MINFREE (64 * 1024) 109 #define MINFREEFRACT 2 110 111 /* 112 * Believed threshold (in megabytes) for which interleaved 113 * swapping area is desirable. 114 */ 115 #define LOTSOFMEM 2 116 117 /* 118 * BEWARE THIS DEFINITION WORKS ONLY WITH COUNT OF 1 119 */ 120 #define mapin(pte, v, pfnum, count, prot) \ 121 (*(int *)(pte) = (pfnum) | (prot), mtpr(TBIS, ptob(v))) 122