mpool.h revision 1540
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. */ 48typedef 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. */ 62typedef 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 69typedef 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 124MPOOL *mpool_open __P((DBT *, int, pgno_t, pgno_t)); 125void mpool_filter __P((MPOOL *, void (*)(void *, pgno_t, void *), 126 void (*)(void *, pgno_t, void *), void *)); 127void *mpool_new __P((MPOOL *, pgno_t *)); 128void *mpool_get __P((MPOOL *, pgno_t, u_int)); 129int mpool_put __P((MPOOL *, void *, u_int)); 130int mpool_sync __P((MPOOL *)); 131int mpool_close __P((MPOOL *)); 132#ifdef STATISTICS 133void mpool_stat __P((MPOOL *)); 134#endif 135__END_DECLS 136