1/*-
2 * SPDX-License-Identifier: BSD-3-Clause
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
32#ifndef _MPOOL_H_
33#define _MPOOL_H_
34
35#include <sys/queue.h>
36
37/*
38 * The memory pool scheme is a simple one. Each in-memory page is referenced
39 * by a bucket which is threaded in up to two of three ways. All active pages
40 * are threaded on a hash chain (hashed by page number) and an lru chain.
41 * Inactive pages are threaded on a free chain. Each reference to a memory
42 * pool is handed an opaque MPOOL cookie which stores all of this information.
43 */
44#define HASHSIZE 128
45#define HASHKEY(pgno) ((pgno - 1 + HASHSIZE) % HASHSIZE)
46
47/* The BKT structures are the elements of the queues. */
48typedef struct _bkt {
49 TAILQ_ENTRY(_bkt) hq; /* hash queue */
50 TAILQ_ENTRY(_bkt) q; /* lru queue */
51 void *page; /* page */
52 pgno_t pgno; /* page number */
53
54#define MPOOL_DIRTY 0x01 /* page needs to be written */
55#define MPOOL_PINNED 0x02 /* page is pinned into memory */
56#define MPOOL_INUSE 0x04 /* page address is valid */
57 u_int8_t flags; /* flags */
58} BKT;
59
60typedef struct MPOOL {
61 TAILQ_HEAD(_lqh, _bkt) lqh; /* lru queue head */
62 /* hash queue array */
63 TAILQ_HEAD(_hqh, _bkt) hqh[HASHSIZE];
64 pgno_t curcache; /* current number of cached pages */
65 pgno_t maxcache; /* max number of cached pages */
66 pgno_t npages; /* number of pages in the file */
67 unsigned long pagesize; /* file page size */
68 int fd; /* file descriptor */
69 /* page in conversion routine */
70 void (*pgin)(void *, pgno_t, void *);
71 /* page out conversion routine */
72 void (*pgout)(void *, pgno_t, void *);
73 void *pgcookie; /* cookie for page in/out routines */
74#ifdef STATISTICS
75 unsigned long cachehit;
76 unsigned long cachemiss;
77 unsigned long pagealloc;
78 unsigned long pageflush;
79 unsigned long pageget;
80 unsigned long pagenew;
81 unsigned long pageput;
82 unsigned long pageread;
83 unsigned long pagewrite;
84#endif
85} MPOOL;
86
87#define MPOOL_IGNOREPIN 0x01 /* Ignore if the page is pinned. */
88#define MPOOL_PAGE_REQUEST 0x01 /* Allocate a new page with a
89 specific page number. */
90#define MPOOL_PAGE_NEXT 0x02 /* Allocate a new page with the next
91 page number. */
92
93__BEGIN_DECLS
94MPOOL *mpool_open(void *, int, pgno_t, pgno_t);
95void mpool_filter(MPOOL *, void (*)(void *, pgno_t, void *),
96 void (*)(void *, pgno_t, void *), void *);
97void *mpool_new(MPOOL *, pgno_t *, unsigned int);
98void *mpool_get(MPOOL *, pgno_t, unsigned int);
99int mpool_delete(MPOOL *, void *);
100int mpool_put(MPOOL *, void *, unsigned int);
101int mpool_sync(MPOOL *);
102int mpool_close(MPOOL *);
103#ifdef STATISTICS
104void mpool_stat(MPOOL *);
105#endif
106__END_DECLS
107
108#endif