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: src/include/mpool.h,v 1.9 2002/03/23 17:24:53 imp Exp $
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. */
53typedef 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
64typedef 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	unsigned 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	unsigned long	cachehit;
80	unsigned long	cachemiss;
81	unsigned long	pagealloc;
82	unsigned long	pageflush;
83	unsigned long	pageget;
84	unsigned long	pagenew;
85	unsigned long	pageput;
86	unsigned long	pageread;
87	unsigned long	pagewrite;
88#endif
89} MPOOL;
90
91__BEGIN_DECLS
92MPOOL	*mpool_open(void *, int, pgno_t, pgno_t);
93void	 mpool_filter(MPOOL *, void (*)(void *, pgno_t, void *),
94	    void (*)(void *, pgno_t, void *), void *);
95void	*mpool_new(MPOOL *, pgno_t *);
96void	*mpool_get(MPOOL *, pgno_t, unsigned int);
97int	 mpool_put(MPOOL *, void *, unsigned int);
98int	 mpool_sync(MPOOL *);
99int	 mpool_close(MPOOL *);
100#ifdef STATISTICS
101void	 mpool_stat(MPOOL *);
102#endif
103__END_DECLS
104
105#endif
106