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