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Annotation of 42BSD/sys/vax/vmparam.h, revision 1.1

1.1     ! root        1: /*     vmparam.h       6.1     83/07/29        */
        !             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)))

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