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. */ 51 typedef 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. */ 65 typedef 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 72 typedef 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 127 MPOOL *mpool_open __P((DBT *, int, pgno_t, pgno_t)); 128 void mpool_filter __P((MPOOL *, void (*)(void *, pgno_t, void *), 129 void (*)(void *, pgno_t, void *), void *)); 130 void *mpool_new __P((MPOOL *, pgno_t *)); 131 void *mpool_get __P((MPOOL *, pgno_t, u_int)); 132 int mpool_put __P((MPOOL *, void *, u_int)); 133 int mpool_sync __P((MPOOL *)); 134 int mpool_close __P((MPOOL *)); 135 #ifdef STATISTICS 136 void mpool_stat __P((MPOOL *)); 137 #endif 138 __END_DECLS 139 140 #endif 141