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

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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 */
35
36#ifndef _MPOOL_H_
37#define _MPOOL_H_
38
39#include <sys/queue.h>
40
41/*
42 * The memory pool scheme is a simple one. Each in-memory page is referenced
43 * by a bucket which is threaded in up to two of three ways. All active pages
44 * are threaded on a hash chain (hashed by page number) and an lru chain.
45 * Inactive pages are threaded on a free chain. Each reference to a memory
46 * pool is handed an opaque MPOOL cookie which stores all of this information.
47 */
48#define HASHSIZE 128
49#define HASHKEY(pgno) ((pgno - 1) % HASHSIZE)
50
51/* The BKT structures are the elements of the queues. */
52typedef struct _bkt {
53 CIRCLEQ_ENTRY(_bkt) hq; /* hash queue */
54 CIRCLEQ_ENTRY(_bkt) q; /* lru queue */
55 void *page; /* page */
56 pgno_t pgno; /* page number */
57
58#define MPOOL_DIRTY 0x01 /* page needs to be written */
59#define MPOOL_PINNED 0x02 /* page is pinned into memory */
60 u_int8_t flags; /* flags */
61} BKT;
62
63typedef struct MPOOL {
64 CIRCLEQ_HEAD(_lqh, _bkt) lqh; /* lru queue head */
65 /* hash queue array */
66 CIRCLEQ_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 u_long pagesize; /* file page size */
71 int fd; /* file descriptor */
72 /* page in conversion routine */
73 void (*pgin) __P((void *, pgno_t, void *));
74 /* page out conversion routine */
75 void (*pgout) __P((void *, pgno_t, void *));
76 void *pgcookie; /* cookie for page in/out routines */
77#ifdef STATISTICS
78 u_long cachehit;
79 u_long cachemiss;
80 u_long pagealloc;
81 u_long pageflush;
82 u_long pageget;
83 u_long pagenew;
84 u_long pageput;
85 u_long pageread;
86 u_long pagewrite;
87#endif
88} MPOOL;
89
90__BEGIN_DECLS
91MPOOL *mpool_open __P((void *, int, pgno_t, pgno_t));
92void mpool_filter __P((MPOOL *, void (*)(void *, pgno_t, void *),
93 void (*)(void *, pgno_t, void *), void *));
94void *mpool_new __P((MPOOL *, pgno_t *));
95void *mpool_get __P((MPOOL *, pgno_t, u_int));
96int mpool_put __P((MPOOL *, void *, u_int));
97int mpool_sync __P((MPOOL *));
98int mpool_close __P((MPOOL *));
99#ifdef STATISTICS
100void mpool_stat __P((MPOOL *));
101#endif
102__END_DECLS
103
104#endif