1 /*- 2 * Copyright (c) 1991, 1993, 1994 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 8.2 (Berkeley) 7/14/94 34 * $FreeBSD$ 35 */ 36 37 #ifndef _MPOOL_H_ 38 #define _MPOOL_H_ 39 40 #include <sys/queue.h> 41 42 /* 43 * The memory pool scheme is a simple one. Each in-memory page is referenced 44 * by a bucket which is threaded in up to two of three ways. All active pages 45 * are threaded on a hash chain (hashed by page number) and an lru chain. 46 * Inactive pages are threaded on a free chain. Each reference to a memory 47 * pool is handed an opaque MPOOL cookie which stores all of this information. 48 */ 49 #define HASHSIZE 128 50 #define HASHKEY(pgno) ((pgno - 1) % HASHSIZE) 51 52 /* The BKT structures are the elements of the queues. */ 53 typedef struct _bkt { 54 TAILQ_ENTRY(_bkt) hq; /* hash queue */ 55 TAILQ_ENTRY(_bkt) q; /* lru queue */ 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 u_int8_t flags; /* flags */ 62 } BKT; 63 64 typedef struct MPOOL { 65 TAILQ_HEAD(_lqh, _bkt) lqh; /* lru queue head */ 66 /* hash queue array */ 67 TAILQ_HEAD(_hqh, _bkt) hqh[HASHSIZE]; 68 pgno_t curcache; /* current number of cached pages */ 69 pgno_t maxcache; /* max number of cached pages */ 70 pgno_t npages; /* number of pages in the file */ 71 u_long pagesize; /* file page size */ 72 int fd; /* file descriptor */ 73 /* page in conversion routine */ 74 void (*pgin)(void *, pgno_t, void *); 75 /* page out conversion routine */ 76 void (*pgout)(void *, pgno_t, void *); 77 void *pgcookie; /* cookie for page in/out routines */ 78 #ifdef STATISTICS 79 u_long cachehit; 80 u_long cachemiss; 81 u_long pagealloc; 82 u_long pageflush; 83 u_long pageget; 84 u_long pagenew; 85 u_long pageput; 86 u_long pageread; 87 u_long pagewrite; 88 #endif 89 } MPOOL; 90 91 __BEGIN_DECLS 92 MPOOL *mpool_open(void *, int, pgno_t, pgno_t); 93 void mpool_filter(MPOOL *, void (*)(void *, pgno_t, void *), 94 void (*)(void *, pgno_t, void *), void *); 95 void *mpool_new(MPOOL *, pgno_t *); 96 void *mpool_get(MPOOL *, pgno_t, u_int); 97 int mpool_put(MPOOL *, void *, u_int); 98 int mpool_sync(MPOOL *); 99 int mpool_close(MPOOL *); 100 #ifdef STATISTICS 101 void mpool_stat(MPOOL *); 102 #endif 103 __END_DECLS 104 105 #endif 106