mpool.h (4242B) - Raw
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 * @(#)mpool.h 8.4 (Berkeley) 11/2/95 32 */ 33 34 #ifndef _MPOOL_H_ 35 #define _MPOOL_H_ 36 37 #include <sys/queue.h> 38 39 /* 40 * The memory pool scheme is a simple one. Each in-memory page is referenced 41 * by a bucket which is threaded in up to two of three ways. All active pages 42 * are threaded on a hash chain (hashed by page number) and an lru chain. 43 * Inactive pages are threaded on a free chain. Each reference to a memory 44 * pool is handed an opaque MPOOL cookie which stores all of this information. 45 */ 46 #define HASHSIZE 128 47 #define HASHKEY(pgno) ((pgno - 1 + HASHSIZE) % HASHSIZE) 48 49 /* The BKT structures are the elements of the queues. */ 50 typedef struct _bkt { 51 TAILQ_ENTRY(_bkt) hq; /* hash queue */ 52 TAILQ_ENTRY(_bkt) q; /* lru queue */ 53 void *page; /* page */ 54 pgno_t pgno; /* page number */ 55 56 #define MPOOL_DIRTY 0x01 /* page needs to be written */ 57 #define MPOOL_PINNED 0x02 /* page is pinned into memory */ 58 #define MPOOL_INUSE 0x04 /* page address is valid */ 59 u_int8_t flags; /* flags */ 60 } BKT; 61 62 typedef struct MPOOL { 63 TAILQ_HEAD(_lqh, _bkt) lqh; /* lru queue head */ 64 /* hash queue array */ 65 TAILQ_HEAD(_hqh, _bkt) hqh[HASHSIZE]; 66 pgno_t curcache; /* current number of cached pages */ 67 pgno_t maxcache; /* max number of cached pages */ 68 pgno_t npages; /* number of pages in the file */ 69 unsigned long pagesize; /* file page size */ 70 int fd; /* file descriptor */ 71 /* page in conversion routine */ 72 void (*pgin)(void *, pgno_t, void *); 73 /* page out conversion routine */ 74 void (*pgout)(void *, pgno_t, void *); 75 void *pgcookie; /* cookie for page in/out routines */ 76 #ifdef STATISTICS 77 unsigned long cachehit; 78 unsigned long cachemiss; 79 unsigned long pagealloc; 80 unsigned long pageflush; 81 unsigned long pageget; 82 unsigned long pagenew; 83 unsigned long pageput; 84 unsigned long pageread; 85 unsigned long pagewrite; 86 #endif 87 } MPOOL; 88 89 #define MPOOL_IGNOREPIN 0x01 /* Ignore if the page is pinned. */ 90 #define MPOOL_PAGE_REQUEST 0x01 /* Allocate a new page with a 91 specific page number. */ 92 #define MPOOL_PAGE_NEXT 0x02 /* Allocate a new page with the next 93 page number. */ 94 95 __BEGIN_DECLS 96 MPOOL *mpool_open(void *, int, pgno_t, pgno_t); 97 void mpool_filter(MPOOL *, void (*)(void *, pgno_t, void *), 98 void (*)(void *, pgno_t, void *), void *); 99 void *mpool_new(MPOOL *, pgno_t *, unsigned int); 100 void *mpool_get(MPOOL *, pgno_t, unsigned int); 101 int mpool_delete(MPOOL *, void *); 102 int mpool_put(MPOOL *, void *, unsigned int); 103 int mpool_sync(MPOOL *); 104 int mpool_close(MPOOL *); 105 #ifdef STATISTICS 106 void mpool_stat(MPOOL *); 107 #endif 108 __END_DECLS 109 110 #endif