bsd/include/mpool.h

   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