Home | History | Annotate | Line # | Download | only in include 
      1 /*	$NetBSD: mpool.h,v 1.16 2016/09/24 21:18:09 christos Exp $	*/
      2 
      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	8.2 (Berkeley) 7/14/94
     32  */
     33 
     34 #ifndef _MPOOL_H_
     35 #define _MPOOL_H_
     36 
     37 #include <sys/cdefs.h>
     38 #include <sys/queue.h>
     39 
     40 /*
     41  * The memory pool scheme is a simple one.  Each in-memory page is referenced
     42  * by a bucket which is threaded in up to two of three ways.  All active pages
     43  * are threaded on a hash chain (hashed by page number) and an lru chain.
     44  * Inactive pages are threaded on a free chain.  Each reference to a memory
     45  * pool is handed an opaque MPOOL cookie which stores all of this information.
     46  */
     47 #define	HASHSIZE	128
     48 #define	HASHKEY(pgno)	((pgno - 1) % HASHSIZE)
     49 
     50 /* The BKT structures are the elements of the queues. */
     51 typedef struct _bkt {
     52 	TAILQ_ENTRY(_bkt) hq;		/* hash queue */
     53 	TAILQ_ENTRY(_bkt) q;		/* lru queue */
     54 	void    *page;			/* page */
     55 	pgno_t   pgno;			/* page number */
     56 
     57 #define	MPOOL_DIRTY	0x01		/* page needs to be written */
     58 #define	MPOOL_PINNED	0x02		/* page is pinned into memory */
     59 #define	MPOOL_INUSE	0x04		/* page address is valid */
     60 	uint8_t flags;			/* flags */
     61 } BKT;
     62 
     63 typedef struct MPOOL {
     64 	TAILQ_HEAD(_lqh, _bkt) lqh;	/* lru queue head */
     65 					/* hash queue array */
     66 	TAILQ_HEAD(_hqh, _bkt) hqh[HASHSIZE];
     67 	pgno_t	curcache;		/* current number of cached pages */
     68 	pgno_t	maxcache;		/* max number of cached pages */
     69 	pgno_t	npages;			/* number of pages in the file */
     70 	unsigned long	pagesize;		/* file page size */
     71 	int	fd;			/* file descriptor */
     72 					/* page in conversion routine */
     73 	void    (*pgin)(void *, pgno_t, void *);
     74 					/* page out conversion routine */
     75 	void    (*pgout)(void *, pgno_t, void *);
     76 	void	*pgcookie;		/* cookie for page in/out routines */
     77 #ifdef STATISTICS
     78 	unsigned long	cachehit;
     79 	unsigned long	cachemiss;
     80 	unsigned long	pagealloc;
     81 	unsigned long	pageflush;
     82 	unsigned long	pageget;
     83 	unsigned long	pagenew;
     84 	unsigned long	pageput;
     85 	unsigned long	pageread;
     86 	unsigned long	pagewrite;
     87 #endif
     88 } MPOOL;
     89 
     90 /* flags for get/put */
     91 #define	MPOOL_IGNOREPIN		0x01	/* Ignore if the page is pinned. */
     92 /* flags for newf */
     93 #define	MPOOL_PAGE_REQUEST	0x01	/* Allocate a new page with a
     94 					   specific page number. */
     95 #define	MPOOL_PAGE_NEXT		0x02	/* Allocate a new page with the next
     96 					   page number. */
     97 
     98 __BEGIN_DECLS
     99 MPOOL	*mpool_open(void *, int, pgno_t, pgno_t);
    100 void	 mpool_filter(MPOOL *, void (*)(void *, pgno_t, void *),
    101 	    void (*)(void *, pgno_t, void *), void *);
    102 void	*mpool_new(MPOOL *, pgno_t *);
    103 void	*mpool_newf(MPOOL *, pgno_t *, unsigned int);
    104 int	 mpool_delete(MPOOL *, void *);
    105 void	*mpool_get(MPOOL *, pgno_t, unsigned int);
    106 int	 mpool_put(MPOOL *, void *, unsigned int);
    107 int	 mpool_sync(MPOOL *);
    108 int	 mpool_close(MPOOL *);
    109 #ifdef STATISTICS
    110 void	 mpool_stat(MPOOL *);
    111 #endif
    112 __END_DECLS
    113 
    114 #endif /* _MPOOL_H_ */
    115