mpool.h

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/*-
 * Copyright (c) 1991, 1993, 1994
 * The Regents of the University of California. All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 * notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 * notice, this list of conditions and the following disclaimer in the
 * documentation and/or other materials provided with the distribution.
 * 3. All advertising materials mentioning features or use of this software
 * must display the following acknowledgement:
 * This product includes software developed by the University of
 * California, Berkeley and its contributors.
 * 4. Neither the name of the University nor the names of its contributors
 * may be used to endorse or promote products derived from this software
 * without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 *
 * @(#)mpool.h 8.2 (Berkeley) 7/14/94
 */

#ifndef _MPOOL_H
#define _MPOOL_H 1

#include <sys/queue.h>
#ifndef CIRCLEQ_HEAD
#include <circ-queue.h>
#endif

/*
 * The memory pool scheme is a simple one. Each in-memory page is referenced
 * by a bucket which is threaded in up to two of three ways. All active pages
 * are threaded on a hash chain (hashed by page number) and an lru chain.
 * Inactive pages are threaded on a free chain. Each reference to a memory
 * pool is handed an opaque MPOOL cookie which stores all of this information.
 */
#define HASHSIZE 128
#define HASHKEY(pgno) ((pgno - 1) % HASHSIZE)

/* The BKT structures are the elements of the queues. */
typedef struct _bkt {
 CIRCLEQ_ENTRY(_bkt) hq; /* hash queue */
 CIRCLEQ_ENTRY(_bkt) q; /* lru queue */
 void *page; /* page */
 pgno_t pgno; /* page number */

#define MPOOL_DIRTY 0x01 /* page needs to be written */
#define MPOOL_PINNED 0x02 /* page is pinned into memory */
 u_int8_t flags; /* flags */
} BKT;

typedef struct MPOOL {
 CIRCLEQ_HEAD(_lqh, _bkt) lqh; /* lru queue head */
 /* hash queue array */
 CIRCLEQ_HEAD(_hqh, _bkt) hqh[HASHSIZE];
 pgno_t curcache; /* current number of cached pages */
 pgno_t maxcache; /* max number of cached pages */
 pgno_t npages; /* number of pages in the file */
 u_long pagesize; /* file page size */
 int fd; /* file descriptor */
 /* page in conversion routine */
 void (*pgin) __P((void *, pgno_t, void *));
 /* page out conversion routine */
 void (*pgout) __P((void *, pgno_t, void *));
 void *pgcookie; /* cookie for page in/out routines */
#ifdef STATISTICS
 u_long cachehit;
 u_long cachemiss;
 u_long pagealloc;
 u_long pageflush;
 u_long pageget;
 u_long pagenew;
 u_long pageput;
 u_long pageread;
 u_long pagewrite;
#endif
} MPOOL;

__BEGIN_DECLS
MPOOL *__mpool_open __P((void *, int, pgno_t, pgno_t));
MPOOL *mpool_open __P((void *, int, pgno_t, pgno_t));
void __mpool_filter __P((MPOOL *, void (*)(void *, pgno_t, void *),
 void (*)(void *, pgno_t, void *), void *));
void mpool_filter __P((MPOOL *, void (*)(void *, pgno_t, void *),
 void (*)(void *, pgno_t, void *), void *));
void *__mpool_new __P((MPOOL *, pgno_t *));
void *mpool_new __P((MPOOL *, pgno_t *));
void *__mpool_get __P((MPOOL *, pgno_t, u_int));
void *mpool_get __P((MPOOL *, pgno_t, u_int));
int __mpool_put __P((MPOOL *, void *, u_int));
int mpool_put __P((MPOOL *, void *, u_int));
int __mpool_sync __P((MPOOL *));
int mpool_sync __P((MPOOL *));
int __mpool_close __P((MPOOL *));
int mpool_close __P((MPOOL *));
#ifdef STATISTICS
void mpool_stat __P((MPOOL *));
#endif
__END_DECLS

#endif /* mpool.h */