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28e48405 RG |
1 | /*- |
2 | * Copyright (c) 1991, 1993 | |
3 | * The Regents of the University of California. All rights reserved. | |
4 | * | |
5 | * Redistribution and use in source and binary forms, with or without | |
6 | * modification, are permitted provided that the following conditions | |
7 | * are met: | |
8 | * 1. Redistributions of source code must retain the above copyright | |
9 | * notice, this list of conditions and the following disclaimer. | |
10 | * 2. Redistributions in binary form must reproduce the above copyright | |
11 | * notice, this list of conditions and the following disclaimer in the | |
12 | * documentation and/or other materials provided with the distribution. | |
13 | * 3. All advertising materials mentioning features or use of this software | |
14 | * must display the following acknowledgement: | |
15 | * This product includes software developed by the University of | |
16 | * California, Berkeley and its contributors. | |
17 | * 4. Neither the name of the University nor the names of its contributors | |
18 | * may be used to endorse or promote products derived from this software | |
19 | * without specific prior written permission. | |
20 | * | |
21 | * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND | |
22 | * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE | |
23 | * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE | |
24 | * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE | |
25 | * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL | |
26 | * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS | |
27 | * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) | |
28 | * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT | |
29 | * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY | |
30 | * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF | |
31 | * SUCH DAMAGE. | |
32 | * | |
33 | * @(#)mpool.h 8.1 (Berkeley) 6/2/93 | |
34 | */ | |
35 | ||
36 | /* | |
37 | * The memory pool scheme is a simple one. Each in memory page is referenced | |
38 | * by a bucket which is threaded in three ways. All active pages are threaded | |
39 | * on a hash chain (hashed by the page number) and an lru chain. Inactive | |
40 | * pages are threaded on a free chain. Each reference to a memory pool is | |
41 | * handed an MPOOL which is the opaque cookie passed to all of the memory | |
42 | * routines. | |
43 | */ | |
44 | #define HASHSIZE 128 | |
45 | #define HASHKEY(pgno) ((pgno - 1) % HASHSIZE) | |
46 | ||
47 | /* The BKT structures are the elements of the lists. */ | |
48 | typedef struct BKT { | |
49 | struct BKT *hnext; /* next hash bucket */ | |
50 | struct BKT *hprev; /* previous hash bucket */ | |
51 | struct BKT *cnext; /* next free/lru bucket */ | |
52 | struct BKT *cprev; /* previous free/lru bucket */ | |
53 | void *page; /* page */ | |
54 | pgno_t pgno; /* page number */ | |
55 | ||
56 | #define MPOOL_DIRTY 0x01 /* page needs to be written */ | |
57 | #define MPOOL_PINNED 0x02 /* page is pinned into memory */ | |
58 | unsigned long flags; /* flags */ | |
59 | } BKT; | |
60 | ||
61 | /* The BKTHDR structures are the heads of the lists. */ | |
62 | typedef struct BKTHDR { | |
63 | struct BKT *hnext; /* next hash bucket */ | |
64 | struct BKT *hprev; /* previous hash bucket */ | |
65 | struct BKT *cnext; /* next free/lru bucket */ | |
66 | struct BKT *cprev; /* previous free/lru bucket */ | |
67 | } BKTHDR; | |
68 | ||
69 | typedef struct MPOOL { | |
70 | BKTHDR free; /* The free list. */ | |
71 | BKTHDR lru; /* The LRU list. */ | |
72 | BKTHDR hashtable[HASHSIZE]; /* Hashed list by page number. */ | |
73 | pgno_t curcache; /* Current number of cached pages. */ | |
74 | pgno_t maxcache; /* Max number of cached pages. */ | |
75 | pgno_t npages; /* Number of pages in the file. */ | |
76 | u_long pagesize; /* File page size. */ | |
77 | int fd; /* File descriptor. */ | |
78 | /* Page in conversion routine. */ | |
79 | void (*pgin) __P((void *, pgno_t, void *)); | |
80 | /* Page out conversion routine. */ | |
81 | void (*pgout) __P((void *, pgno_t, void *)); | |
82 | void *pgcookie; /* Cookie for page in/out routines. */ | |
83 | #ifdef STATISTICS | |
84 | unsigned long cachehit; | |
85 | unsigned long cachemiss; | |
86 | unsigned long pagealloc; | |
87 | unsigned long pageflush; | |
88 | unsigned long pageget; | |
89 | unsigned long pagenew; | |
90 | unsigned long pageput; | |
91 | unsigned long pageread; | |
92 | unsigned long pagewrite; | |
93 | #endif | |
94 | } MPOOL; | |
95 | ||
96 | #ifdef __MPOOLINTERFACE_PRIVATE | |
97 | /* Macros to insert/delete into/from hash chain. */ | |
98 | #define rmhash(bp) { \ | |
99 | (bp)->hprev->hnext = (bp)->hnext; \ | |
100 | (bp)->hnext->hprev = (bp)->hprev; \ | |
101 | } | |
102 | #define inshash(bp, pg) { \ | |
103 | hp = &mp->hashtable[HASHKEY(pg)]; \ | |
104 | (bp)->hnext = hp->hnext; \ | |
105 | (bp)->hprev = (struct BKT *)hp; \ | |
106 | hp->hnext->hprev = (bp); \ | |
107 | hp->hnext = (bp); \ | |
108 | } | |
109 | ||
110 | /* Macros to insert/delete into/from lru and free chains. */ | |
111 | #define rmchain(bp) { \ | |
112 | (bp)->cprev->cnext = (bp)->cnext; \ | |
113 | (bp)->cnext->cprev = (bp)->cprev; \ | |
114 | } | |
115 | #define inschain(bp, dp) { \ | |
116 | (bp)->cnext = (dp)->cnext; \ | |
117 | (bp)->cprev = (struct BKT *)(dp); \ | |
118 | (dp)->cnext->cprev = (bp); \ | |
119 | (dp)->cnext = (bp); \ | |
120 | } | |
121 | #endif | |
122 | ||
123 | __BEGIN_DECLS | |
124 | MPOOL *mpool_open __P((DBT *, int, pgno_t, pgno_t)); | |
125 | void mpool_filter __P((MPOOL *, void (*)(void *, pgno_t, void *), | |
126 | void (*)(void *, pgno_t, void *), void *)); | |
127 | void *mpool_new __P((MPOOL *, pgno_t *)); | |
128 | void *mpool_get __P((MPOOL *, pgno_t, u_int)); | |
129 | int mpool_put __P((MPOOL *, void *, u_int)); | |
130 | int mpool_sync __P((MPOOL *)); | |
131 | int mpool_close __P((MPOOL *)); | |
132 | #ifdef STATISTICS | |
133 | void mpool_stat __P((MPOOL *)); | |
134 | #endif | |
135 | __END_DECLS |