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. Neither the name of the University nor the names of its contributors 14 * may be used to endorse or promote products derived from this software 15 * without specific prior written permission. 16 * 17 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 18 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 19 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 20 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 21 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 22 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 23 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 24 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 25 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 26 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 27 * SUCH DAMAGE. 28 * 29 * @(#)mpool.h 8.4 (Berkeley) 11/2/95 30 * $FreeBSD: head/include/mpool.h 203964 2010-02-16 19:39:50Z imp $ 31 */ 32 33 #ifndef _MPOOL_H_ 34 #define _MPOOL_H_ 35 36 #include <sys/cdefs.h> 37 #include <sys/queue.h> 38 #include <db.h> 39 40 /* 41 * The memory pool scheme is a simple one. Each in-memory page is referenced 42 * by a bucket which is threaded in up to two of three ways. All active pages 43 * are threaded on a hash chain (hashed by page number) and an lru chain. 44 * Inactive pages are threaded on a free chain. Each reference to a memory 45 * pool is handed an opaque MPOOL cookie which stores all of this information. 46 */ 47 #define HASHSIZE 128 48 #define HASHKEY(pgno) ((pgno - 1 + HASHSIZE) % HASHSIZE) 49 50 /* The BKT structures are the elements of the queues. */ 51 typedef struct _bkt { 52 TAILQ_ENTRY(_bkt) hq; /* hash queue */ 53 TAILQ_ENTRY(_bkt) q; /* lru queue */ 54 void *page; /* page */ 55 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 #define MPOOL_INUSE 0x04 /* page address is valid */ 60 u_int8_t flags; /* flags */ 61 } BKT; 62 63 typedef struct MPOOL { 64 TAILQ_HEAD(_lqh, _bkt) lqh; /* lru queue head */ 65 /* hash queue array */ 66 TAILQ_HEAD(_hqh, _bkt) hqh[HASHSIZE]; 67 pgno_t curcache; /* current number of cached pages */ 68 pgno_t maxcache; /* max number of cached pages */ 69 pgno_t npages; /* number of pages in the file */ 70 unsigned long pagesize; /* file page size */ 71 int fd; /* file descriptor */ 72 /* page in conversion routine */ 73 void (*pgin)(void *, pgno_t, void *); 74 /* page out conversion routine */ 75 void (*pgout)(void *, pgno_t, void *); 76 void *pgcookie; /* cookie for page in/out routines */ 77 #ifdef STATISTICS 78 unsigned long cachehit; 79 unsigned long cachemiss; 80 unsigned long pagealloc; 81 unsigned long pageflush; 82 unsigned long pageget; 83 unsigned long pagenew; 84 unsigned long pageput; 85 unsigned long pageread; 86 unsigned long pagewrite; 87 #endif 88 } MPOOL; 89 90 #define MPOOL_IGNOREPIN 0x01 /* Ignore if the page is pinned. */ 91 #define MPOOL_PAGE_REQUEST 0x01 /* Allocate a new page with a 92 specific page number. */ 93 #define MPOOL_PAGE_NEXT 0x02 /* Allocate a new page with the next 94 page number. */ 95 96 __BEGIN_DECLS 97 MPOOL *mpool_open(void *, int, pgno_t, pgno_t); 98 void mpool_filter(MPOOL *, void (*)(void *, pgno_t, void *), 99 void (*)(void *, pgno_t, void *), void *); 100 void *mpool_new(MPOOL *, pgno_t *, unsigned int); 101 void *mpool_get(MPOOL *, pgno_t, unsigned int); 102 int mpool_delete(MPOOL *, void *); 103 int mpool_put(MPOOL *, void *, unsigned int); 104 int mpool_sync(MPOOL *); 105 int mpool_close(MPOOL *); 106 #ifdef STATISTICS 107 void mpool_stat(MPOOL *); 108 #endif 109 __END_DECLS 110 111 #endif 112