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