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1.1 root 1: /*
2: * Copyright (c) 1999 Apple Computer, Inc. All rights reserved.
3: *
4: * @APPLE_LICENSE_HEADER_START@
5: *
6: * Portions Copyright (c) 1999 Apple Computer, Inc. All Rights
7: * Reserved. This file contains Original Code and/or Modifications of
8: * Original Code as defined in and that are subject to the Apple Public
9: * Source License Version 1.1 (the "License"). You may not use this file
10: * except in compliance with the License. Please obtain a copy of the
11: * License at http://www.apple.com/publicsource and read it before using
12: * this file.
13: *
14: * The Original Code and all software distributed under the License are
15: * distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY KIND, EITHER
16: * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
17: * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
18: * FITNESS FOR A PARTICULAR PURPOSE OR NON-INFRINGEMENT. Please see the
19: * License for the specific language governing rights and limitations
20: * under the License.
21: *
22: * @APPLE_LICENSE_HEADER_END@
23: */
24:
25: /*-
26: * Copyright (c) 1991, 1993
27: * The Regents of the University of California. All rights reserved.
28: *
29: * Redistribution and use in source and binary forms, with or without
30: * modification, are permitted provided that the following conditions
31: * are met:
32: * 1. Redistributions of source code must retain the above copyright
33: * notice, this list of conditions and the following disclaimer.
34: * 2. Redistributions in binary form must reproduce the above copyright
35: * notice, this list of conditions and the following disclaimer in the
36: * documentation and/or other materials provided with the distribution.
37: * 3. All advertising materials mentioning features or use of this software
38: * must display the following acknowledgement:
39: * This product includes software developed by the University of
40: * California, Berkeley and its contributors.
41: * 4. Neither the name of the University nor the names of its contributors
42: * may be used to endorse or promote products derived from this software
43: * without specific prior written permission.
44: *
45: * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
46: * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
47: * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
48: * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
49: * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
50: * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
51: * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
52: * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
53: * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
54: * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
55: * SUCH DAMAGE.
56: *
57: * @(#)mpool.h 8.1 (Berkeley) 6/2/93
58: */
59:
60: /*
61: * The memory pool scheme is a simple one. Each in memory page is referenced
62: * by a bucket which is threaded in three ways. All active pages are threaded
63: * on a hash chain (hashed by the page number) and an lru chain. Inactive
64: * pages are threaded on a free chain. Each reference to a memory pool is
65: * handed an MPOOL which is the opaque cookie passed to all of the memory
66: * routines.
67: */
68: #define HASHSIZE 128
69: #define HASHKEY(pgno) ((pgno - 1) % HASHSIZE)
70:
71: /* The BKT structures are the elements of the lists. */
72: typedef struct BKT {
73: struct BKT *hnext; /* next hash bucket */
74: struct BKT *hprev; /* previous hash bucket */
75: struct BKT *cnext; /* next free/lru bucket */
76: struct BKT *cprev; /* previous free/lru bucket */
77: void *page; /* page */
78: pgno_t pgno; /* page number */
79:
80: #define MPOOL_DIRTY 0x01 /* page needs to be written */
81: #define MPOOL_PINNED 0x02 /* page is pinned into memory */
82: unsigned long flags; /* flags */
83: } BKT;
84:
85: /* The BKTHDR structures are the heads of the lists. */
86: typedef struct BKTHDR {
87: struct BKT *hnext; /* next hash bucket */
88: struct BKT *hprev; /* previous hash bucket */
89: struct BKT *cnext; /* next free/lru bucket */
90: struct BKT *cprev; /* previous free/lru bucket */
91: } BKTHDR;
92:
93: typedef struct MPOOL {
94: BKTHDR free; /* The free list. */
95: BKTHDR lru; /* The LRU list. */
96: BKTHDR hashtable[HASHSIZE]; /* Hashed list by page number. */
97: pgno_t curcache; /* Current number of cached pages. */
98: pgno_t maxcache; /* Max number of cached pages. */
99: pgno_t npages; /* Number of pages in the file. */
100: u_long pagesize; /* File page size. */
101: int fd; /* File descriptor. */
102: /* Page in conversion routine. */
103: void (*pgin) __P((void *, pgno_t, void *));
104: /* Page out conversion routine. */
105: void (*pgout) __P((void *, pgno_t, void *));
106: void *pgcookie; /* Cookie for page in/out routines. */
107: #ifdef STATISTICS
108: unsigned long cachehit;
109: unsigned long cachemiss;
110: unsigned long pagealloc;
111: unsigned long pageflush;
112: unsigned long pageget;
113: unsigned long pagenew;
114: unsigned long pageput;
115: unsigned long pageread;
116: unsigned long pagewrite;
117: #endif
118: } MPOOL;
119:
120: #ifdef __MPOOLINTERFACE_PRIVATE
121: /* Macros to insert/delete into/from hash chain. */
122: #define rmhash(bp) { \
123: (bp)->hprev->hnext = (bp)->hnext; \
124: (bp)->hnext->hprev = (bp)->hprev; \
125: }
126: #define inshash(bp, pg) { \
127: hp = &mp->hashtable[HASHKEY(pg)]; \
128: (bp)->hnext = hp->hnext; \
129: (bp)->hprev = (struct BKT *)hp; \
130: hp->hnext->hprev = (bp); \
131: hp->hnext = (bp); \
132: }
133:
134: /* Macros to insert/delete into/from lru and free chains. */
135: #define rmchain(bp) { \
136: (bp)->cprev->cnext = (bp)->cnext; \
137: (bp)->cnext->cprev = (bp)->cprev; \
138: }
139: #define inschain(bp, dp) { \
140: (bp)->cnext = (dp)->cnext; \
141: (bp)->cprev = (struct BKT *)(dp); \
142: (dp)->cnext->cprev = (bp); \
143: (dp)->cnext = (bp); \
144: }
145: #endif
146:
147: __BEGIN_DECLS
148: MPOOL *mpool_open __P((DBT *, int, pgno_t, pgno_t));
149: void mpool_filter __P((MPOOL *, void (*)(void *, pgno_t, void *),
150: void (*)(void *, pgno_t, void *), void *));
151: void *mpool_new __P((MPOOL *, pgno_t *));
152: void *mpool_get __P((MPOOL *, pgno_t, u_int));
153: int mpool_put __P((MPOOL *, void *, u_int));
154: int mpool_sync __P((MPOOL *));
155: int mpool_close __P((MPOOL *));
156: #ifdef STATISTICS
157: void mpool_stat __P((MPOOL *));
158: #endif
159: __END_DECLS
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