1/*	$NetBSD: mpool.h,v 1.16 2016/09/24 21:18:09 christos Exp $	*/
2
3/*-
4 * Copyright (c) 1991, 1993, 1994
5 *	The Regents of the University of California.  All rights reserved.
6 *
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
9 * are met:
10 * 1. Redistributions of source code must retain the above copyright
11 *    notice, this list of conditions and the following disclaimer.
12 * 2. Redistributions in binary form must reproduce the above copyright
13 *    notice, this list of conditions and the following disclaimer in the
14 *    documentation and/or other materials provided with the distribution.
15 * 3. Neither the name of the University nor the names of its contributors
16 *    may be used to endorse or promote products derived from this software
17 *    without specific prior written permission.
18 *
19 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
20 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
21 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
22 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
23 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
24 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
25 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
26 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
27 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
28 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
29 * SUCH DAMAGE.
30 *
31 *	@(#)mpool.h	8.2 (Berkeley) 7/14/94
32 */
33
34#ifndef _MPOOL_H_
35#define _MPOOL_H_
36
37#include <sys/cdefs.h>
38#include <sys/queue.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)
49
50/* The BKT structures are the elements of the queues. */
51typedef 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	uint8_t flags;			/* flags */
61} BKT;
62
63typedef 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/* flags for get/put */
91#define	MPOOL_IGNOREPIN		0x01	/* Ignore if the page is pinned. */
92/* flags for newf */
93#define	MPOOL_PAGE_REQUEST	0x01	/* Allocate a new page with a
94					   specific page number. */
95#define	MPOOL_PAGE_NEXT		0x02	/* Allocate a new page with the next
96					   page number. */
97
98__BEGIN_DECLS
99MPOOL	*mpool_open(void *, int, pgno_t, pgno_t);
100void	 mpool_filter(MPOOL *, void (*)(void *, pgno_t, void *),
101	    void (*)(void *, pgno_t, void *), void *);
102void	*mpool_new(MPOOL *, pgno_t *);
103void	*mpool_newf(MPOOL *, pgno_t *, unsigned int);
104int	 mpool_delete(MPOOL *, void *);
105void	*mpool_get(MPOOL *, pgno_t, unsigned int);
106int	 mpool_put(MPOOL *, void *, unsigned int);
107int	 mpool_sync(MPOOL *);
108int	 mpool_close(MPOOL *);
109#ifdef STATISTICS
110void	 mpool_stat(MPOOL *);
111#endif
112__END_DECLS
113
114#endif /* _MPOOL_H_ */
115