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Annotation of XNU/bsd/include/mpool.h, revision 1.1

1.1     ! root        1: /*
        !             2:  * Copyright (c) 2000 Apple Computer, Inc. All rights reserved.
        !             3:  *
        !             4:  * @APPLE_LICENSE_HEADER_START@
        !             5:  * 
        !             6:  * The contents of this file constitute Original Code as defined in and
        !             7:  * are subject to the Apple Public Source License Version 1.1 (the
        !             8:  * "License").  You may not use this file except in compliance with the
        !             9:  * License.  Please obtain a copy of the License at
        !            10:  * http://www.apple.com/publicsource and read it before using this file.
        !            11:  * 
        !            12:  * This Original Code and all software distributed under the License are
        !            13:  * distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY KIND, EITHER
        !            14:  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
        !            15:  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
        !            16:  * FITNESS FOR A PARTICULAR PURPOSE OR NON-INFRINGEMENT.  Please see the
        !            17:  * License for the specific language governing rights and limitations
        !            18:  * under the License.
        !            19:  * 
        !            20:  * @APPLE_LICENSE_HEADER_END@
        !            21:  */
        !            22: /*-
        !            23:  * Copyright (c) 1991, 1993
        !            24:  *     The Regents of the University of California.  All rights reserved.
        !            25:  *
        !            26:  * Redistribution and use in source and binary forms, with or without
        !            27:  * modification, are permitted provided that the following conditions
        !            28:  * are met:
        !            29:  * 1. Redistributions of source code must retain the above copyright
        !            30:  *    notice, this list of conditions and the following disclaimer.
        !            31:  * 2. Redistributions in binary form must reproduce the above copyright
        !            32:  *    notice, this list of conditions and the following disclaimer in the
        !            33:  *    documentation and/or other materials provided with the distribution.
        !            34:  * 3. All advertising materials mentioning features or use of this software
        !            35:  *    must display the following acknowledgement:
        !            36:  *     This product includes software developed by the University of
        !            37:  *     California, Berkeley and its contributors.
        !            38:  * 4. Neither the name of the University nor the names of its contributors
        !            39:  *    may be used to endorse or promote products derived from this software
        !            40:  *    without specific prior written permission.
        !            41:  *
        !            42:  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
        !            43:  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
        !            44:  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
        !            45:  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
        !            46:  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
        !            47:  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
        !            48:  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
        !            49:  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
        !            50:  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
        !            51:  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
        !            52:  * SUCH DAMAGE.
        !            53:  *
        !            54:  *     @(#)mpool.h     8.1 (Berkeley) 6/2/93
        !            55:  */
        !            56: 
        !            57: /*
        !            58:  * The memory pool scheme is a simple one.  Each in memory page is referenced
        !            59:  * by a bucket which is threaded in three ways.  All active pages are threaded
        !            60:  * on a hash chain (hashed by the page number) and an lru chain.  Inactive
        !            61:  * pages are threaded on a free chain.  Each reference to a memory pool is
        !            62:  * handed an MPOOL which is the opaque cookie passed to all of the memory
        !            63:  * routines.
        !            64:  */
        !            65: #define        HASHSIZE        128
        !            66: #define        HASHKEY(pgno)   ((pgno - 1) % HASHSIZE)
        !            67: 
        !            68: /* The BKT structures are the elements of the lists. */
        !            69: typedef struct BKT {
        !            70:        struct BKT      *hnext;         /* next hash bucket */
        !            71:        struct BKT      *hprev;         /* previous hash bucket */
        !            72:        struct BKT      *cnext;         /* next free/lru bucket */
        !            73:        struct BKT      *cprev;         /* previous free/lru bucket */
        !            74:        void            *page;          /* page */
        !            75:        pgno_t          pgno;           /* page number */
        !            76: 
        !            77: #define        MPOOL_DIRTY     0x01            /* page needs to be written */
        !            78: #define        MPOOL_PINNED    0x02            /* page is pinned into memory */
        !            79:        unsigned long   flags;          /* flags */
        !            80: } BKT;
        !            81: 
        !            82: /* The BKTHDR structures are the heads of the lists. */
        !            83: typedef struct BKTHDR {
        !            84:        struct BKT      *hnext;         /* next hash bucket */
        !            85:        struct BKT      *hprev;         /* previous hash bucket */
        !            86:        struct BKT      *cnext;         /* next free/lru bucket */
        !            87:        struct BKT      *cprev;         /* previous free/lru bucket */
        !            88: } BKTHDR;
        !            89: 
        !            90: typedef struct MPOOL {
        !            91:        BKTHDR  free;                   /* The free list. */
        !            92:        BKTHDR  lru;                    /* The LRU list. */
        !            93:        BKTHDR  hashtable[HASHSIZE];    /* Hashed list by page number. */
        !            94:        pgno_t  curcache;               /* Current number of cached pages. */
        !            95:        pgno_t  maxcache;               /* Max number of cached pages. */
        !            96:        pgno_t  npages;                 /* Number of pages in the file. */
        !            97:        u_long  pagesize;               /* File page size. */
        !            98:        int     fd;                     /* File descriptor. */
        !            99:                                        /* Page in conversion routine. */
        !           100:        void    (*pgin) __P((void *, pgno_t, void *));
        !           101:                                        /* Page out conversion routine. */
        !           102:        void    (*pgout) __P((void *, pgno_t, void *));
        !           103:        void    *pgcookie;              /* Cookie for page in/out routines. */
        !           104: #ifdef STATISTICS
        !           105:        unsigned long   cachehit;
        !           106:        unsigned long   cachemiss;
        !           107:        unsigned long   pagealloc;
        !           108:        unsigned long   pageflush;
        !           109:        unsigned long   pageget;
        !           110:        unsigned long   pagenew;
        !           111:        unsigned long   pageput;
        !           112:        unsigned long   pageread;
        !           113:        unsigned long   pagewrite;
        !           114: #endif
        !           115: } MPOOL;
        !           116: 
        !           117: #ifdef __MPOOLINTERFACE_PRIVATE
        !           118: /* Macros to insert/delete into/from hash chain. */
        !           119: #define rmhash(bp) { \
        !           120:         (bp)->hprev->hnext = (bp)->hnext; \
        !           121:         (bp)->hnext->hprev = (bp)->hprev; \
        !           122: }
        !           123: #define inshash(bp, pg) { \
        !           124:        hp = &mp->hashtable[HASHKEY(pg)]; \
        !           125:         (bp)->hnext = hp->hnext; \
        !           126:         (bp)->hprev = (struct BKT *)hp; \
        !           127:         hp->hnext->hprev = (bp); \
        !           128:         hp->hnext = (bp); \
        !           129: }
        !           130: 
        !           131: /* Macros to insert/delete into/from lru and free chains. */
        !           132: #define        rmchain(bp) { \
        !           133:         (bp)->cprev->cnext = (bp)->cnext; \
        !           134:         (bp)->cnext->cprev = (bp)->cprev; \
        !           135: }
        !           136: #define inschain(bp, dp) { \
        !           137:         (bp)->cnext = (dp)->cnext; \
        !           138:         (bp)->cprev = (struct BKT *)(dp); \
        !           139:         (dp)->cnext->cprev = (bp); \
        !           140:         (dp)->cnext = (bp); \
        !           141: }
        !           142: #endif
        !           143: 
        !           144: __BEGIN_DECLS
        !           145: MPOOL  *mpool_open __P((DBT *, int, pgno_t, pgno_t));
        !           146: void    mpool_filter __P((MPOOL *, void (*)(void *, pgno_t, void *),
        !           147:            void (*)(void *, pgno_t, void *), void *));
        !           148: void   *mpool_new __P((MPOOL *, pgno_t *));
        !           149: void   *mpool_get __P((MPOOL *, pgno_t, u_int));
        !           150: int     mpool_put __P((MPOOL *, void *, u_int));
        !           151: int     mpool_sync __P((MPOOL *));
        !           152: int     mpool_close __P((MPOOL *));
        !           153: #ifdef STATISTICS
        !           154: void    mpool_stat __P((MPOOL *));
        !           155: #endif
        !           156: __END_DECLS

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