mpool.h revision 2162
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#ifndef _MPOOL_H_ 37#define _MPOOL_H_ 38 39/* 40 * The memory pool scheme is a simple one. Each in memory page is referenced 41 * by a bucket which is threaded in three ways. All active pages are threaded 42 * on a hash chain (hashed by the page number) and an lru chain. Inactive 43 * pages are threaded on a free chain. Each reference to a memory pool is 44 * handed an MPOOL which is the opaque cookie passed to all of the memory 45 * routines. 46 */ 47#define HASHSIZE 128 48#define HASHKEY(pgno) ((pgno - 1) % HASHSIZE) 49 50/* The BKT structures are the elements of the lists. */ 51typedef struct BKT { 52 struct BKT *hnext; /* next hash bucket */ 53 struct BKT *hprev; /* previous hash bucket */ 54 struct BKT *cnext; /* next free/lru bucket */ 55 struct BKT *cprev; /* previous free/lru bucket */ 56 void *page; /* page */ 57 pgno_t pgno; /* page number */ 58 59#define MPOOL_DIRTY 0x01 /* page needs to be written */ 60#define MPOOL_PINNED 0x02 /* page is pinned into memory */ 61 unsigned long flags; /* flags */ 62} BKT; 63 64/* The BKTHDR structures are the heads of the lists. */ 65typedef struct BKTHDR { 66 struct BKT *hnext; /* next hash bucket */ 67 struct BKT *hprev; /* previous hash bucket */ 68 struct BKT *cnext; /* next free/lru bucket */ 69 struct BKT *cprev; /* previous free/lru bucket */ 70} BKTHDR; 71 72typedef struct MPOOL { 73 BKTHDR free; /* The free list. */ 74 BKTHDR lru; /* The LRU list. */ 75 BKTHDR hashtable[HASHSIZE]; /* Hashed list by page number. */ 76 pgno_t curcache; /* Current number of cached pages. */ 77 pgno_t maxcache; /* Max number of cached pages. */ 78 pgno_t npages; /* Number of pages in the file. */ 79 u_long pagesize; /* File page size. */ 80 int fd; /* File descriptor. */ 81 /* Page in conversion routine. */ 82 void (*pgin) __P((void *, pgno_t, void *)); 83 /* Page out conversion routine. */ 84 void (*pgout) __P((void *, pgno_t, void *)); 85 void *pgcookie; /* Cookie for page in/out routines. */ 86#ifdef STATISTICS 87 unsigned long cachehit; 88 unsigned long cachemiss; 89 unsigned long pagealloc; 90 unsigned long pageflush; 91 unsigned long pageget; 92 unsigned long pagenew; 93 unsigned long pageput; 94 unsigned long pageread; 95 unsigned long pagewrite; 96#endif 97} MPOOL; 98 99#ifdef __MPOOLINTERFACE_PRIVATE 100/* Macros to insert/delete into/from hash chain. */ 101#define rmhash(bp) { \ 102 (bp)->hprev->hnext = (bp)->hnext; \ 103 (bp)->hnext->hprev = (bp)->hprev; \ 104} 105#define inshash(bp, pg) { \ 106 hp = &mp->hashtable[HASHKEY(pg)]; \ 107 (bp)->hnext = hp->hnext; \ 108 (bp)->hprev = (struct BKT *)hp; \ 109 hp->hnext->hprev = (bp); \ 110 hp->hnext = (bp); \ 111} 112 113/* Macros to insert/delete into/from lru and free chains. */ 114#define rmchain(bp) { \ 115 (bp)->cprev->cnext = (bp)->cnext; \ 116 (bp)->cnext->cprev = (bp)->cprev; \ 117} 118#define inschain(bp, dp) { \ 119 (bp)->cnext = (dp)->cnext; \ 120 (bp)->cprev = (struct BKT *)(dp); \ 121 (dp)->cnext->cprev = (bp); \ 122 (dp)->cnext = (bp); \ 123} 124#endif 125 126__BEGIN_DECLS 127MPOOL *mpool_open __P((DBT *, int, pgno_t, pgno_t)); 128void mpool_filter __P((MPOOL *, void (*)(void *, pgno_t, void *), 129 void (*)(void *, pgno_t, void *), void *)); 130void *mpool_new __P((MPOOL *, pgno_t *)); 131void *mpool_get __P((MPOOL *, pgno_t, u_int)); 132int mpool_put __P((MPOOL *, void *, u_int)); 133int mpool_sync __P((MPOOL *)); 134int mpool_close __P((MPOOL *)); 135#ifdef STATISTICS 136void mpool_stat __P((MPOOL *)); 137#endif 138__END_DECLS 139 140#endif 141