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1 | /*- |
2 | * Copyright (c) 1991 The Regents of the University of California. | |
3 | * All rights reserved. | |
4 | * | |
5 | * %sccs.include.redist.c% | |
6 | * | |
93a5373b | 7 | * @(#)mpool.h 5.2 (Berkeley) %G% |
43dfd197 KB |
8 | */ |
9 | ||
10 | /* | |
11 | * The memory pool scheme is a simple one. Each in memory page is referenced | |
12 | * by a bucket which is threaded in three ways. All active pages are threaded | |
13 | * on a hash chain (hashed by the page number) and an lru chain. Inactive | |
14 | * pages are threaded on a free chain. Each reference to a memory pool is | |
15 | * handed an MPOOL which is the opaque cookie passed to all of the memory | |
16 | * routines. | |
17 | */ | |
18 | #define HASHSIZE 128 | |
19 | #define HASHKEY(pgno) ((pgno - 1) % HASHSIZE) | |
20 | ||
21 | /* The BKT structures are the elements of the lists. */ | |
22 | typedef struct BKT { | |
23 | struct BKT *hnext; /* next hash bucket */ | |
24 | struct BKT *hprev; /* previous hash bucket */ | |
25 | struct BKT *cnext; /* next free/lru bucket */ | |
26 | struct BKT *cprev; /* previous free/lru bucket */ | |
27 | void *page; /* page */ | |
28 | pgno_t pgno; /* page number */ | |
29 | ||
30 | #define MPOOL_DIRTY 0x01 /* page needs to be written */ | |
31 | #define MPOOL_PINNED 0x02 /* page is pinned into memory */ | |
32 | unsigned long flags; /* flags */ | |
33 | } BKT; | |
34 | ||
35 | /* The BKTHDR structures are the heads of the lists. */ | |
36 | typedef struct BKTHDR { | |
37 | struct BKT *hnext; /* next hash bucket */ | |
38 | struct BKT *hprev; /* previous hash bucket */ | |
39 | struct BKT *cnext; /* next free/lru bucket */ | |
40 | struct BKT *cprev; /* previous free/lru bucket */ | |
41 | } BKTHDR; | |
42 | ||
43 | typedef struct MPOOL { | |
44 | BKTHDR free; /* The free list. */ | |
45 | BKTHDR lru; /* The LRU list. */ | |
46 | BKTHDR hashtable[HASHSIZE]; /* Hashed list by page number. */ | |
47 | pgno_t curcache; /* Current number of cached pages. */ | |
48 | pgno_t maxcache; /* Max number of cached pages. */ | |
49 | pgno_t npages; /* Number of pages in the file. */ | |
93a5373b | 50 | indx_t pagesize; /* File page size. */ |
43dfd197 KB |
51 | int fd; /* File descriptor. */ |
52 | /* Page in conversion routine. */ | |
53 | void (*pgin) __P((void *, pgno_t, void *)); | |
54 | /* Page out conversion routine. */ | |
55 | void (*pgout) __P((void *, pgno_t, void *)); | |
56 | void *pgcookie; /* Cookie for page in/out routines. */ | |
57 | #ifdef STATISTICS | |
58 | unsigned long cachehit; | |
59 | unsigned long cachemiss; | |
60 | unsigned long pagealloc; | |
61 | unsigned long pageflush; | |
62 | unsigned long pageget; | |
63 | unsigned long pagenew; | |
64 | unsigned long pageput; | |
65 | unsigned long pageread; | |
66 | unsigned long pagewrite; | |
67 | #endif | |
68 | } MPOOL; | |
69 | ||
70 | #ifdef __MPOOLINTERFACE_PRIVATE | |
71 | /* Macros to insert/delete into/from hash chain. */ | |
72 | #define rmhash(bp) { \ | |
73 | (bp)->hprev->hnext = (bp)->hnext; \ | |
74 | (bp)->hnext->hprev = (bp)->hprev; \ | |
75 | } | |
76 | #define inshash(bp, pg) { \ | |
77 | hp = &mp->hashtable[HASHKEY(pg)]; \ | |
78 | (bp)->hnext = hp->hnext; \ | |
79 | (bp)->hprev = (struct BKT *)hp; \ | |
80 | hp->hnext->hprev = (bp); \ | |
81 | hp->hnext = (bp); \ | |
82 | } | |
83 | ||
84 | /* Macros to insert/delete into/from lru and free chains. */ | |
85 | #define rmchain(bp) { \ | |
86 | (bp)->cprev->cnext = (bp)->cnext; \ | |
87 | (bp)->cnext->cprev = (bp)->cprev; \ | |
88 | } | |
89 | #define inschain(bp, dp) { \ | |
90 | (bp)->cnext = (dp)->cnext; \ | |
91 | (bp)->cprev = (struct BKT *)(dp); \ | |
92 | (dp)->cnext->cprev = (bp); \ | |
93 | (dp)->cnext = (bp); \ | |
94 | } | |
95 | #endif | |
96 | ||
97 | __BEGIN_DECLS | |
98 | MPOOL *mpool_open __P((DBT *, int, pgno_t, pgno_t)); | |
99 | void mpool_filter __P((MPOOL *, void (*)(void *, pgno_t, void *), | |
100 | void (*)(void *, pgno_t, void *), void *)); | |
101 | void *mpool_new __P((MPOOL *, pgno_t *)); | |
102 | void *mpool_get __P((MPOOL *, pgno_t, u_int)); | |
103 | int mpool_put __P((MPOOL *, void *, u_int)); | |
104 | int mpool_sync __P((MPOOL *)); | |
105 | int mpool_close __P((MPOOL *)); | |
106 | #ifdef STATISTICS | |
107 | void mpool_stat __P((MPOOL *)); | |
108 | #endif | |
109 | __END_DECLS |