freebsd-skq/include/mpool.h
Xin LI 9fc74a871c Minor changes from Berkeley DB 1.86 and further improvements from OpenBSD.
This does not include the new hash routines since they will cause problems
when reading old hash files.

Since mpool(3) has been changed, provide a compatibility shim for older
binaries.

Obtained from:	OpenBSD
2009-03-28 07:31:02 +00:00

114 lines
4.3 KiB
C

/*-
* 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 8.4 (Berkeley) 11/2/95
* $FreeBSD$
*/
#ifndef _MPOOL_H_
#define _MPOOL_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) % 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 */
#define MPOOL_INUSE 0x04 /* page address is valid */
u_int8_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;
#define MPOOL_IGNOREPIN 0x01 /* Ignore if the page is pinned. */
#define MPOOL_PAGE_REQUEST 0x01 /* Allocate a new page with a
specific page number. */
#define MPOOL_PAGE_NEXT 0x02 /* Allocate a new page with the next
page number. */
__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 *, unsigned int);
void *mpool_get(MPOOL *, pgno_t, unsigned int);
int mpool_delete(MPOOL *, void *);
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