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1.1 root 1: /*
2: * Copyright (c) 2000 Apple Computer, Inc. All rights reserved.
3: *
4: * @APPLE_LICENSE_HEADER_START@
5: *
6: * The contents of this file constitute Original Code as defined in and
7: * are subject to the Apple Public Source License Version 1.1 (the
8: * "License"). You may not use this file except in compliance with the
9: * License. Please obtain a copy of the License at
10: * http://www.apple.com/publicsource and read it before using this file.
11: *
12: * This Original Code and all software distributed under the License are
13: * distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY KIND, EITHER
14: * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
15: * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
16: * FITNESS FOR A PARTICULAR PURPOSE OR NON-INFRINGEMENT. Please see the
17: * License for the specific language governing rights and limitations
18: * under the License.
19: *
20: * @APPLE_LICENSE_HEADER_END@
21: */
22: /*-
23: * Copyright (c) 1991, 1993
24: * The Regents of the University of California. All rights reserved.
25: *
26: * Redistribution and use in source and binary forms, with or without
27: * modification, are permitted provided that the following conditions
28: * are met:
29: * 1. Redistributions of source code must retain the above copyright
30: * notice, this list of conditions and the following disclaimer.
31: * 2. Redistributions in binary form must reproduce the above copyright
32: * notice, this list of conditions and the following disclaimer in the
33: * documentation and/or other materials provided with the distribution.
34: * 3. All advertising materials mentioning features or use of this software
35: * must display the following acknowledgement:
36: * This product includes software developed by the University of
37: * California, Berkeley and its contributors.
38: * 4. Neither the name of the University nor the names of its contributors
39: * may be used to endorse or promote products derived from this software
40: * without specific prior written permission.
41: *
42: * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
43: * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
44: * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
45: * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
46: * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
47: * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
48: * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
49: * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
50: * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
51: * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
52: * SUCH DAMAGE.
53: *
54: * @(#)mpool.h 8.1 (Berkeley) 6/2/93
55: */
56:
57: /*
58: * The memory pool scheme is a simple one. Each in memory page is referenced
59: * by a bucket which is threaded in three ways. All active pages are threaded
60: * on a hash chain (hashed by the page number) and an lru chain. Inactive
61: * pages are threaded on a free chain. Each reference to a memory pool is
62: * handed an MPOOL which is the opaque cookie passed to all of the memory
63: * routines.
64: */
65: #define HASHSIZE 128
66: #define HASHKEY(pgno) ((pgno - 1) % HASHSIZE)
67:
68: /* The BKT structures are the elements of the lists. */
69: typedef struct BKT {
70: struct BKT *hnext; /* next hash bucket */
71: struct BKT *hprev; /* previous hash bucket */
72: struct BKT *cnext; /* next free/lru bucket */
73: struct BKT *cprev; /* previous free/lru bucket */
74: void *page; /* page */
75: pgno_t pgno; /* page number */
76:
77: #define MPOOL_DIRTY 0x01 /* page needs to be written */
78: #define MPOOL_PINNED 0x02 /* page is pinned into memory */
79: unsigned long flags; /* flags */
80: } BKT;
81:
82: /* The BKTHDR structures are the heads of the lists. */
83: typedef struct BKTHDR {
84: struct BKT *hnext; /* next hash bucket */
85: struct BKT *hprev; /* previous hash bucket */
86: struct BKT *cnext; /* next free/lru bucket */
87: struct BKT *cprev; /* previous free/lru bucket */
88: } BKTHDR;
89:
90: typedef struct MPOOL {
91: BKTHDR free; /* The free list. */
92: BKTHDR lru; /* The LRU list. */
93: BKTHDR hashtable[HASHSIZE]; /* Hashed list by page number. */
94: pgno_t curcache; /* Current number of cached pages. */
95: pgno_t maxcache; /* Max number of cached pages. */
96: pgno_t npages; /* Number of pages in the file. */
97: u_long pagesize; /* File page size. */
98: int fd; /* File descriptor. */
99: /* Page in conversion routine. */
100: void (*pgin) __P((void *, pgno_t, void *));
101: /* Page out conversion routine. */
102: void (*pgout) __P((void *, pgno_t, void *));
103: void *pgcookie; /* Cookie for page in/out routines. */
104: #ifdef STATISTICS
105: unsigned long cachehit;
106: unsigned long cachemiss;
107: unsigned long pagealloc;
108: unsigned long pageflush;
109: unsigned long pageget;
110: unsigned long pagenew;
111: unsigned long pageput;
112: unsigned long pageread;
113: unsigned long pagewrite;
114: #endif
115: } MPOOL;
116:
117: #ifdef __MPOOLINTERFACE_PRIVATE
118: /* Macros to insert/delete into/from hash chain. */
119: #define rmhash(bp) { \
120: (bp)->hprev->hnext = (bp)->hnext; \
121: (bp)->hnext->hprev = (bp)->hprev; \
122: }
123: #define inshash(bp, pg) { \
124: hp = &mp->hashtable[HASHKEY(pg)]; \
125: (bp)->hnext = hp->hnext; \
126: (bp)->hprev = (struct BKT *)hp; \
127: hp->hnext->hprev = (bp); \
128: hp->hnext = (bp); \
129: }
130:
131: /* Macros to insert/delete into/from lru and free chains. */
132: #define rmchain(bp) { \
133: (bp)->cprev->cnext = (bp)->cnext; \
134: (bp)->cnext->cprev = (bp)->cprev; \
135: }
136: #define inschain(bp, dp) { \
137: (bp)->cnext = (dp)->cnext; \
138: (bp)->cprev = (struct BKT *)(dp); \
139: (dp)->cnext->cprev = (bp); \
140: (dp)->cnext = (bp); \
141: }
142: #endif
143:
144: __BEGIN_DECLS
145: MPOOL *mpool_open __P((DBT *, int, pgno_t, pgno_t));
146: void mpool_filter __P((MPOOL *, void (*)(void *, pgno_t, void *),
147: void (*)(void *, pgno_t, void *), void *));
148: void *mpool_new __P((MPOOL *, pgno_t *));
149: void *mpool_get __P((MPOOL *, pgno_t, u_int));
150: int mpool_put __P((MPOOL *, void *, u_int));
151: int mpool_sync __P((MPOOL *));
152: int mpool_close __P((MPOOL *));
153: #ifdef STATISTICS
154: void mpool_stat __P((MPOOL *));
155: #endif
156: __END_DECLS
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