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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. 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
 */
#include "queue.h" /* * 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)(void *, pgno_t, void *); /* page out conversion routine */
void (*pgout)(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; MPOOL *mpool_open(void *, int, pgno_t, pgno_t); void mpool_filter(MPOOL *, void (*)(void *, pgno_t, void *), void (*)(void *, pgno_t, void *), void *); void *mpool_new(MPOOL *, pgno_t *); void *mpool_get(MPOOL *, pgno_t, u_int); int mpool_put(MPOOL *, void *, u_int); int mpool_sync(MPOOL *); int mpool_close(MPOOL *); #ifdef STATISTICS void mpool_stat(MPOOL *); #endif

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