104 lines
		
	
	
		
			3.8 KiB
		
	
	
	
		
			C
		
	
	
	
	
	
			
		
		
	
	
			104 lines
		
	
	
		
			3.8 KiB
		
	
	
	
		
			C
		
	
	
	
	
	
/*	$NetBSD: mpool.h,v 1.13 2008/08/26 21:18:38 joerg Exp $	*/
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/*-
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 * Copyright (c) 1991, 1993, 1994
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 *	The Regents of the University of California.  All rights reserved.
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 *
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 * Redistribution and use in source and binary forms, with or without
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 * modification, are permitted provided that the following conditions
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 * are met:
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 * 1. Redistributions of source code must retain the above copyright
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 *    notice, this list of conditions and the following disclaimer.
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 * 2. Redistributions in binary form must reproduce the above copyright
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 *    notice, this list of conditions and the following disclaimer in the
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 *    documentation and/or other materials provided with the distribution.
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 * 3. Neither the name of the University nor the names of its contributors
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 *    may be used to endorse or promote products derived from this software
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 *    without specific prior written permission.
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 *
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 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
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 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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 * SUCH DAMAGE.
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 *
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 *	@(#)mpool.h	8.2 (Berkeley) 7/14/94
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 */
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#ifndef _MPOOL_H_
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#define _MPOOL_H_
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#include <sys/cdefs.h>
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#include <sys/queue.h>
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/*
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 * The memory pool scheme is a simple one.  Each in-memory page is referenced
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 * by a bucket which is threaded in up to two of three ways.  All active pages
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 * are threaded on a hash chain (hashed by page number) and an lru chain.
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 * Inactive pages are threaded on a free chain.  Each reference to a memory
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 * pool is handed an opaque MPOOL cookie which stores all of this information.
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 */
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#define	HASHSIZE	128
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#define	HASHKEY(pgno)	((pgno - 1) % HASHSIZE)
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/* The BKT structures are the elements of the queues. */
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typedef struct _bkt {
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	CIRCLEQ_ENTRY(_bkt) hq;		/* hash queue */
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	CIRCLEQ_ENTRY(_bkt) q;		/* lru queue */
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	void    *page;			/* page */
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	pgno_t   pgno;			/* page number */
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#define	MPOOL_DIRTY	0x01		/* page needs to be written */
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#define	MPOOL_PINNED	0x02		/* page is pinned into memory */
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	uint8_t flags;			/* flags */
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} BKT;
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typedef struct MPOOL {
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	CIRCLEQ_HEAD(_lqh, _bkt) lqh;	/* lru queue head */
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					/* hash queue array */
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	CIRCLEQ_HEAD(_hqh, _bkt) hqh[HASHSIZE];
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	pgno_t	curcache;		/* current number of cached pages */
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	pgno_t	maxcache;		/* max number of cached pages */
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	pgno_t	npages;			/* number of pages in the file */
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	unsigned long	pagesize;		/* file page size */
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	int	fd;			/* file descriptor */
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					/* page in conversion routine */
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	void    (*pgin)(void *, pgno_t, void *);
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					/* page out conversion routine */
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	void    (*pgout)(void *, pgno_t, void *);
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	void	*pgcookie;		/* cookie for page in/out routines */
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#ifdef STATISTICS
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	unsigned long	cachehit;
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	unsigned long	cachemiss;
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	unsigned long	pagealloc;
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	unsigned long	pageflush;
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	unsigned long	pageget;
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	unsigned long	pagenew;
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	unsigned long	pageput;
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	unsigned long	pageread;
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	unsigned long	pagewrite;
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#endif
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} MPOOL;
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__BEGIN_DECLS
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MPOOL	*mpool_open(void *, int, pgno_t, pgno_t);
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void	 mpool_filter(MPOOL *, void (*)(void *, pgno_t, void *),
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	    void (*)(void *, pgno_t, void *), void *);
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void	*mpool_new(MPOOL *, pgno_t *);
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void	*mpool_get(MPOOL *, pgno_t, unsigned int);
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int	 mpool_put(MPOOL *, void *, unsigned int);
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int	 mpool_sync(MPOOL *);
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int	 mpool_close(MPOOL *);
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#ifdef STATISTICS
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void	 mpool_stat(MPOOL *);
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#endif
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__END_DECLS
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#endif /* _MPOOL_H_ */
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