1 /*- 2 * SPDX-License-Identifier: BSD-3-Clause 3 * 4 * Copyright (c) 1991, 1993, 1994 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. Neither the name of the University nor the names of its contributors 16 * may be used to endorse or promote products derived from this software 17 * without specific prior written permission. 18 * 19 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 20 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 21 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 22 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 23 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 24 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 25 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 26 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 27 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 28 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 29 * SUCH DAMAGE. 30 */ 31 32 #ifndef _MPOOL_H_ 33 #define _MPOOL_H_ 34 35 #include <sys/queue.h> 36 37 /* 38 * The memory pool scheme is a simple one. Each in-memory page is referenced 39 * by a bucket which is threaded in up to two of three ways. All active pages 40 * are threaded on a hash chain (hashed by page number) and an lru chain. 41 * Inactive pages are threaded on a free chain. Each reference to a memory 42 * pool is handed an opaque MPOOL cookie which stores all of this information. 43 */ 44 #define HASHSIZE 128 45 #define HASHKEY(pgno) ((pgno - 1 + HASHSIZE) % HASHSIZE) 46 47 /* The BKT structures are the elements of the queues. */ 48 typedef struct _bkt { 49 TAILQ_ENTRY(_bkt) hq; /* hash queue */ 50 TAILQ_ENTRY(_bkt) q; /* lru queue */ 51 void *page; /* page */ 52 pgno_t pgno; /* page number */ 53 54 #define MPOOL_DIRTY 0x01 /* page needs to be written */ 55 #define MPOOL_PINNED 0x02 /* page is pinned into memory */ 56 #define MPOOL_INUSE 0x04 /* page address is valid */ 57 u_int8_t flags; /* flags */ 58 } BKT; 59 60 typedef struct MPOOL { 61 TAILQ_HEAD(_lqh, _bkt) lqh; /* lru queue head */ 62 /* hash queue array */ 63 TAILQ_HEAD(_hqh, _bkt) hqh[HASHSIZE]; 64 pgno_t curcache; /* current number of cached pages */ 65 pgno_t maxcache; /* max number of cached pages */ 66 pgno_t npages; /* number of pages in the file */ 67 unsigned long pagesize; /* file page size */ 68 int fd; /* file descriptor */ 69 /* page in conversion routine */ 70 void (*pgin)(void *, pgno_t, void *); 71 /* page out conversion routine */ 72 void (*pgout)(void *, pgno_t, void *); 73 void *pgcookie; /* cookie for page in/out routines */ 74 #ifdef STATISTICS 75 unsigned long cachehit; 76 unsigned long cachemiss; 77 unsigned long pagealloc; 78 unsigned long pageflush; 79 unsigned long pageget; 80 unsigned long pagenew; 81 unsigned long pageput; 82 unsigned long pageread; 83 unsigned long pagewrite; 84 #endif 85 } MPOOL; 86 87 #define MPOOL_IGNOREPIN 0x01 /* Ignore if the page is pinned. */ 88 #define MPOOL_PAGE_REQUEST 0x01 /* Allocate a new page with a 89 specific page number. */ 90 #define MPOOL_PAGE_NEXT 0x02 /* Allocate a new page with the next 91 page number. */ 92 93 __BEGIN_DECLS 94 MPOOL *mpool_open(void *, int, pgno_t, pgno_t); 95 void mpool_filter(MPOOL *, void (*)(void *, pgno_t, void *), 96 void (*)(void *, pgno_t, void *), void *); 97 void *mpool_new(MPOOL *, pgno_t *, unsigned int); 98 void *mpool_get(MPOOL *, pgno_t, unsigned int); 99 int mpool_delete(MPOOL *, void *); 100 int mpool_put(MPOOL *, void *, unsigned int); 101 int mpool_sync(MPOOL *); 102 int mpool_close(MPOOL *); 103 #ifdef STATISTICS 104 void mpool_stat(MPOOL *); 105 #endif 106 __END_DECLS 107 108 #endif 109