100 lines
3.9 KiB
C
100 lines
3.9 KiB
C
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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. All advertising materials mentioning features or use of this software
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* must display the following acknowledgement:
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* This product includes software developed by the University of
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* California, Berkeley and its contributors.
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* 4. 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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#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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u_int8_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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u_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) __P((void *, pgno_t, void *));
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/* page out conversion routine */
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void (*pgout) __P((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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u_long cachehit;
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u_long cachemiss;
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u_long pagealloc;
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u_long pageflush;
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u_long pageget;
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u_long pagenew;
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u_long pageput;
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u_long pageread;
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u_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 __P((void *, int, pgno_t, pgno_t));
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void mpool_filter __P((MPOOL *, void (*)(void *, pgno_t, void *),
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void (*)(void *, pgno_t, void *), void *));
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void *mpool_new __P((MPOOL *, pgno_t *));
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void *mpool_get __P((MPOOL *, pgno_t, u_int));
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int mpool_put __P((MPOOL *, void *, u_int));
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int mpool_sync __P((MPOOL *));
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int mpool_close __P((MPOOL *));
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#ifdef STATISTICS
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void mpool_stat __P((MPOOL *));
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#endif
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__END_DECLS
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