* Copyright (c) 1991, 1993, 1994
* The Regents of the University of California. All rights reserved.
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* modification, are permitted provided that the following conditions
* 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
* @(#)mpool.h 8.2 (Berkeley) 7/14/94
* 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 HASHKEY(pgno) ((pgno - 1) % HASHSIZE)
/* The BKT structures are the elements of the queues. */
CIRCLEQ_ENTRY(_bkt
) hq
; /* hash queue */
CIRCLEQ_ENTRY(_bkt
) q
; /* lru queue */
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 */
CIRCLEQ_HEAD(_lqh
, _bkt
) lqh
; /* lru queue head */
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 */
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_new
__P((MPOOL
*, pgno_t
*));
void *mpool_get
__P((MPOOL
*, pgno_t
, u_int
));
int mpool_put
__P((MPOOL
*, void *, u_int
));
int mpool_sync
__P((MPOOL
*));
int mpool_close
__P((MPOOL
*));
void mpool_stat
__P((MPOOL
*));