Annotation of src/include/mpool.h, Revision 1.1.1.1
1.1 deraadt 1: /* $NetBSD: mpool.h,v 1.6 1994/10/26 00:56:07 cgd Exp $ */
2:
3: /*-
4: * Copyright (c) 1991, 1993
5: * The Regents of the University of California. All rights reserved.
6: *
7: * Redistribution and use in source and binary forms, with or without
8: * modification, are permitted provided that the following conditions
9: * are met:
10: * 1. Redistributions of source code must retain the above copyright
11: * notice, this list of conditions and the following disclaimer.
12: * 2. Redistributions in binary form must reproduce the above copyright
13: * notice, this list of conditions and the following disclaimer in the
14: * documentation and/or other materials provided with the distribution.
15: * 3. All advertising materials mentioning features or use of this software
16: * must display the following acknowledgement:
17: * This product includes software developed by the University of
18: * California, Berkeley and its contributors.
19: * 4. Neither the name of the University nor the names of its contributors
20: * may be used to endorse or promote products derived from this software
21: * without specific prior written permission.
22: *
23: * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
24: * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
25: * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
26: * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
27: * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
28: * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
29: * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
30: * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
31: * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
32: * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
33: * SUCH DAMAGE.
34: *
35: * @(#)mpool.h 8.1 (Berkeley) 6/2/93
36: */
37:
38: /*
39: * The memory pool scheme is a simple one. Each in memory page is referenced
40: * by a bucket which is threaded in three ways. All active pages are threaded
41: * on a hash chain (hashed by the page number) and an lru chain. Inactive
42: * pages are threaded on a free chain. Each reference to a memory pool is
43: * handed an MPOOL which is the opaque cookie passed to all of the memory
44: * routines.
45: */
46: #define HASHSIZE 128
47: #define HASHKEY(pgno) ((pgno - 1) % HASHSIZE)
48:
49: /* The BKT structures are the elements of the lists. */
50: typedef struct BKT {
51: struct BKT *hnext; /* next hash bucket */
52: struct BKT *hprev; /* previous hash bucket */
53: struct BKT *cnext; /* next free/lru bucket */
54: struct BKT *cprev; /* previous free/lru bucket */
55: void *page; /* page */
56: pgno_t pgno; /* page number */
57:
58: #define MPOOL_DIRTY 0x01 /* page needs to be written */
59: #define MPOOL_PINNED 0x02 /* page is pinned into memory */
60: unsigned long flags; /* flags */
61: } BKT;
62:
63: /* The BKTHDR structures are the heads of the lists. */
64: typedef struct BKTHDR {
65: struct BKT *hnext; /* next hash bucket */
66: struct BKT *hprev; /* previous hash bucket */
67: struct BKT *cnext; /* next free/lru bucket */
68: struct BKT *cprev; /* previous free/lru bucket */
69: } BKTHDR;
70:
71: typedef struct MPOOL {
72: BKTHDR free; /* The free list. */
73: BKTHDR lru; /* The LRU list. */
74: BKTHDR hashtable[HASHSIZE]; /* Hashed list by page number. */
75: pgno_t curcache; /* Current number of cached pages. */
76: pgno_t maxcache; /* Max number of cached pages. */
77: pgno_t npages; /* Number of pages in the file. */
78: u_long pagesize; /* File page size. */
79: int fd; /* File descriptor. */
80: /* Page in conversion routine. */
81: void (*pgin) __P((void *, pgno_t, void *));
82: /* Page out conversion routine. */
83: void (*pgout) __P((void *, pgno_t, void *));
84: void *pgcookie; /* Cookie for page in/out routines. */
85: #ifdef STATISTICS
86: unsigned long cachehit;
87: unsigned long cachemiss;
88: unsigned long pagealloc;
89: unsigned long pageflush;
90: unsigned long pageget;
91: unsigned long pagenew;
92: unsigned long pageput;
93: unsigned long pageread;
94: unsigned long pagewrite;
95: #endif
96: } MPOOL;
97:
98: #ifdef __MPOOLINTERFACE_PRIVATE
99: /* Macros to insert/delete into/from hash chain. */
100: #define rmhash(bp) { \
101: (bp)->hprev->hnext = (bp)->hnext; \
102: (bp)->hnext->hprev = (bp)->hprev; \
103: }
104: #define inshash(bp, pg) { \
105: hp = &mp->hashtable[HASHKEY(pg)]; \
106: (bp)->hnext = hp->hnext; \
107: (bp)->hprev = (struct BKT *)hp; \
108: hp->hnext->hprev = (bp); \
109: hp->hnext = (bp); \
110: }
111:
112: /* Macros to insert/delete into/from lru and free chains. */
113: #define rmchain(bp) { \
114: (bp)->cprev->cnext = (bp)->cnext; \
115: (bp)->cnext->cprev = (bp)->cprev; \
116: }
117: #define inschain(bp, dp) { \
118: (bp)->cnext = (dp)->cnext; \
119: (bp)->cprev = (struct BKT *)(dp); \
120: (dp)->cnext->cprev = (bp); \
121: (dp)->cnext = (bp); \
122: }
123: #endif
124:
125: __BEGIN_DECLS
126: MPOOL *mpool_open __P((DBT *, int, pgno_t, pgno_t));
127: void mpool_filter __P((MPOOL *, void (*)(void *, pgno_t, void *),
128: void (*)(void *, pgno_t, void *), void *));
129: void *mpool_new __P((MPOOL *, pgno_t *));
130: void *mpool_get __P((MPOOL *, pgno_t, u_int));
131: int mpool_put __P((MPOOL *, void *, u_int));
132: int mpool_sync __P((MPOOL *));
133: int mpool_close __P((MPOOL *));
134: #ifdef STATISTICS
135: void mpool_stat __P((MPOOL *));
136: #endif
137: __END_DECLS
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