xref: /freebsd/include/mpool.h (revision 39beb93c3f8bdbf72a61fda42300b5ebed7390c8)
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