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[glibc.git] / db / mpool.h
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1 /*-
2 * Copyright (c) 1991, 1993, 1994
3 * The Regents of the University of California. All rights reserved.
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.
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.
33 * @(#)mpool.h 8.2 (Berkeley) 7/14/94
36 #ifndef _MPOOL_H
37 #define _MPOOL_H 1
39 #include <sys/queue.h>
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.
48 #define HASHSIZE 128
49 #define HASHKEY(pgno) ((pgno - 1) % HASHSIZE)
51 /* The BKT structures are the elements of the queues. */
52 typedef 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 */
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;
63 typedef 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) __PMT((void *, pgno_t, void *));
74 /* page out conversion routine */
75 void (*pgout) __PMT((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;
90 __BEGIN_DECLS
91 MPOOL *__mpool_open __P((void *, int, pgno_t, pgno_t));
92 MPOOL *mpool_open __P((void *, int, pgno_t, pgno_t));
93 void __mpool_filter __P((MPOOL *, void (*)(void *, pgno_t, void *),
94 void (*)(void *, pgno_t, void *), void *));
95 void mpool_filter __P((MPOOL *, void (*)(void *, pgno_t, void *),
96 void (*)(void *, pgno_t, void *), void *));
97 void *__mpool_new __P((MPOOL *, pgno_t *));
98 void *mpool_new __P((MPOOL *, pgno_t *));
99 void *__mpool_get __P((MPOOL *, pgno_t, u_int));
100 void *mpool_get __P((MPOOL *, pgno_t, u_int));
101 int __mpool_put __P((MPOOL *, void *, u_int));
102 int mpool_put __P((MPOOL *, void *, u_int));
103 int __mpool_sync __P((MPOOL *));
104 int mpool_sync __P((MPOOL *));
105 int __mpool_close __P((MPOOL *));
106 int mpool_close __P((MPOOL *));
107 #ifdef STATISTICS
108 void mpool_stat __P((MPOOL *));
109 #endif
110 __END_DECLS
112 #endif /* mpool.h */