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 */