| 1 | /*-
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| 2 | * Copyright (c) 1991, 1993, 1994
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| 3 | * The Regents of the University of California. All rights reserved.
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| 4 | *
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| 5 | * Redistribution and use in source and binary forms, with or without
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| 6 | * modification, are permitted provided that the following conditions
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| 7 | * are met:
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| 8 | * 1. Redistributions of source code must retain the above copyright
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| 9 | * notice, this list of conditions and the following disclaimer.
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| 10 | * 2. Redistributions in binary form must reproduce the above copyright
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| 11 | * notice, this list of conditions and the following disclaimer in the
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| 12 | * documentation and/or other materials provided with the distribution.
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| 13 | * 3. All advertising materials mentioning features or use of this software
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| 14 | * must display the following acknowledgement:
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| 15 | * This product includes software developed by the University of
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| 16 | * California, Berkeley and its contributors.
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| 17 | * 4. Neither the name of the University nor the names of its contributors
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| 18 | * may be used to endorse or promote products derived from this software
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| 19 | * without specific prior written permission.
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| 20 | *
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| 21 | * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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| 22 | * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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| 23 | * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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| 24 | * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
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| 25 | * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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| 26 | * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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| 27 | * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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| 28 | * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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| 29 | * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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| 30 | * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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| 31 | * SUCH DAMAGE.
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| 32 | *
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| 33 | * @(#)mpool.h 8.2 (Berkeley) 7/14/94
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| 34 | */
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| 35 |
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| 36 | #include <sys/queue.h>
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| 37 |
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| 38 | /*
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| 39 | * The memory pool scheme is a simple one. Each in-memory page is referenced
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| 40 | * by a bucket which is threaded in up to two of three ways. All active pages
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| 41 | * are threaded on a hash chain (hashed by page number) and an lru chain.
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| 42 | * Inactive pages are threaded on a free chain. Each reference to a memory
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| 43 | * pool is handed an opaque MPOOL cookie which stores all of this information.
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| 44 | */
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| 45 | #define HASHSIZE 128
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| 46 | #define HASHKEY(pgno) ((pgno - 1) % HASHSIZE)
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| 47 |
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| 48 | /* The BKT structures are the elements of the queues. */
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| 49 | typedef struct _bkt {
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| 50 | CIRCLEQ_ENTRY(_bkt) hq; /* hash queue */
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| 51 | CIRCLEQ_ENTRY(_bkt) q; /* lru queue */
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| 52 | void *page; /* page */
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| 53 | pgno_t pgno; /* page number */
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| 54 |
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| 55 | #define MPOOL_DIRTY 0x01 /* page needs to be written */
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| 56 | #define MPOOL_PINNED 0x02 /* page is pinned into memory */
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| 57 | u_int8_t flags; /* flags */
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| 58 | } BKT;
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| 59 |
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| 60 | typedef struct MPOOL {
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| 61 | CIRCLEQ_HEAD(_lqh, _bkt) lqh; /* lru queue head */
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| 62 | /* hash queue array */
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| 63 | CIRCLEQ_HEAD(_hqh, _bkt) hqh[HASHSIZE];
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| 64 | pgno_t curcache; /* current number of cached pages */
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| 65 | pgno_t maxcache; /* max number of cached pages */
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| 66 | pgno_t npages; /* number of pages in the file */
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| 67 | u_long pagesize; /* file page size */
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| 68 | int fd; /* file descriptor */
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| 69 | /* page in conversion routine */
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| 70 | void (*pgin) __P((void *, pgno_t, void *));
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| 71 | /* page out conversion routine */
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| 72 | void (*pgout) __P((void *, pgno_t, void *));
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| 73 | void *pgcookie; /* cookie for page in/out routines */
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| 74 | #ifdef STATISTICS
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| 75 | u_long cachehit;
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| 76 | u_long cachemiss;
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| 77 | u_long pagealloc;
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| 78 | u_long pageflush;
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| 79 | u_long pageget;
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| 80 | u_long pagenew;
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| 81 | u_long pageput;
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| 82 | u_long pageread;
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| 83 | u_long pagewrite;
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| 84 | #endif
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| 85 | } MPOOL;
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| 86 |
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| 87 | __BEGIN_DECLS
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| 88 | MPOOL *mpool_open __P((void *, int, pgno_t, pgno_t));
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| 89 | void mpool_filter __P((MPOOL *, void (*)(void *, pgno_t, void *),
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| 90 | void (*)(void *, pgno_t, void *), void *));
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| 91 | void *mpool_new __P((MPOOL *, pgno_t *));
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| 92 | void *mpool_get __P((MPOOL *, pgno_t, u_int));
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| 93 | int mpool_put __P((MPOOL *, void *, u_int));
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| 94 | int mpool_sync __P((MPOOL *));
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| 95 | int mpool_close __P((MPOOL *));
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| 96 | #ifdef STATISTICS
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| 97 | void mpool_stat __P((MPOOL *));
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| 98 | #endif
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| 99 | __END_DECLS
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