LCOM1920-T02G10

/*        $NetBSD: mpool.h,v 1.14 2013/11/22 16:25:01 christos Exp $        */

/*-

 * 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

 */

#ifndef _MPOOL_H_

#define _MPOOL_H_

#include <sys/cdefs.h>

#include <sys/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 {

        TAILQ_ENTRY(_bkt) hq;                /* hash queue */

        TAILQ_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 */

        uint8_t flags;                        /* flags */

} BKT;

typedef struct MPOOL {

        TAILQ_HEAD(_lqh, _bkt) lqh;        /* lru queue head */

                                        /* hash queue array */

        TAILQ_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 */

        unsigned 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

        unsigned long        cachehit;

        unsigned long        cachemiss;

        unsigned long        pagealloc;

        unsigned long        pageflush;

        unsigned long        pageget;

        unsigned long        pagenew;

        unsigned long        pageput;

        unsigned long        pageread;

        unsigned long        pagewrite;

#endif

} MPOOL;

__BEGIN_DECLS

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, unsigned int);

int         mpool_put(MPOOL *, void *, unsigned int);

int         mpool_sync(MPOOL *);

int         mpool_close(MPOOL *);

#ifdef STATISTICS

void         mpool_stat(MPOOL *);

#endif

__END_DECLS

#endif /* _MPOOL_H_ */