1/*-
  2 * SPDX-License-Identifier: BSD-3-Clause
  3 *
  4 * Copyright (c) 1991, 1993, 1994
  5 *	The Regents of the University of California.  All rights reserved.
  6 *
  7 * Redistribution and use in source and binary forms, with or without
  8 * modification, are permitted provided that the following conditions
  9 * are met:
 10 * 1. Redistributions of source code must retain the above copyright
 11 *    notice, this list of conditions and the following disclaimer.
 12 * 2. Redistributions in binary form must reproduce the above copyright
 13 *    notice, this list of conditions and the following disclaimer in the
 14 *    documentation and/or other materials provided with the distribution.
 15 * 3. Neither the name of the University nor the names of its contributors
 16 *    may be used to endorse or promote products derived from this software
 17 *    without specific prior written permission.
 18 *
 19 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
 20 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 21 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 22 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
 23 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 24 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 25 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 26 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 27 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 28 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 29 * SUCH DAMAGE.
 30 *
 31 *	@(#)mpool.h	8.4 (Berkeley) 11/2/95
 32 */
 33
 34#ifndef _MPOOL_H_
 35#define _MPOOL_H_
 36
 37#include <sys/queue.h>
 38
 39/*
 40 * The memory pool scheme is a simple one.  Each in-memory page is referenced
 41 * by a bucket which is threaded in up to two of three ways.  All active pages
 42 * are threaded on a hash chain (hashed by page number) and an lru chain.
 43 * Inactive pages are threaded on a free chain.  Each reference to a memory
 44 * pool is handed an opaque MPOOL cookie which stores all of this information.
 45 */
 46#define	HASHSIZE	128
 47#define	HASHKEY(pgno)	((pgno - 1 + HASHSIZE) % HASHSIZE)
 48
 49/* The BKT structures are the elements of the queues. */
 50typedef struct _bkt {
 51	TAILQ_ENTRY(_bkt) hq;		/* hash queue */
 52	TAILQ_ENTRY(_bkt) q;		/* lru queue */
 53	void    *page;			/* page */
 54	pgno_t   pgno;			/* page number */
 55
 56#define	MPOOL_DIRTY	0x01		/* page needs to be written */
 57#define	MPOOL_PINNED	0x02		/* page is pinned into memory */
 58#define	MPOOL_INUSE	0x04		/* page address is valid */
 59	u_int8_t flags;			/* flags */
 60} BKT;
 61
 62typedef struct MPOOL {
 63	TAILQ_HEAD(_lqh, _bkt) lqh;	/* lru queue head */
 64					/* hash queue array */
 65	TAILQ_HEAD(_hqh, _bkt) hqh[HASHSIZE];
 66	pgno_t	curcache;		/* current number of cached pages */
 67	pgno_t	maxcache;		/* max number of cached pages */
 68	pgno_t	npages;			/* number of pages in the file */
 69	unsigned long	pagesize;	/* file page size */
 70	int	fd;			/* file descriptor */
 71					/* page in conversion routine */
 72	void    (*pgin)(void *, pgno_t, void *);
 73					/* page out conversion routine */
 74	void    (*pgout)(void *, pgno_t, void *);
 75	void	*pgcookie;		/* cookie for page in/out routines */
 76#ifdef STATISTICS
 77	unsigned long	cachehit;
 78	unsigned long	cachemiss;
 79	unsigned long	pagealloc;
 80	unsigned long	pageflush;
 81	unsigned long	pageget;
 82	unsigned long	pagenew;
 83	unsigned long	pageput;
 84	unsigned long	pageread;
 85	unsigned long	pagewrite;
 86#endif
 87} MPOOL;
 88
 89#define	MPOOL_IGNOREPIN	0x01		/* Ignore if the page is pinned. */
 90#define	MPOOL_PAGE_REQUEST	0x01	/* Allocate a new page with a
 91					   specific page number. */
 92#define	MPOOL_PAGE_NEXT		0x02	/* Allocate a new page with the next
 93					  page number. */
 94
 95__BEGIN_DECLS
 96MPOOL	*mpool_open(void *, int, pgno_t, pgno_t);
 97void	 mpool_filter(MPOOL *, void (*)(void *, pgno_t, void *),
 98	    void (*)(void *, pgno_t, void *), void *);
 99void	*mpool_new(MPOOL *, pgno_t *, unsigned int);
100void	*mpool_get(MPOOL *, pgno_t, unsigned int);
101int	 mpool_delete(MPOOL *, void *);
102int	 mpool_put(MPOOL *, void *, unsigned int);
103int	 mpool_sync(MPOOL *);
104int	 mpool_close(MPOOL *);
105#ifdef STATISTICS
106void	 mpool_stat(MPOOL *);
107#endif
108__END_DECLS
109
110#endif