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 */