1 /* 2 * Copyright (c) 2008 The DragonFly Project. All rights reserved. 3 * 4 * This code is derived from software contributed to The DragonFly Project 5 * by Matthew Dillon <dillon@backplane.com> 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 * 11 * 1. Redistributions of source code must retain the above copyright 12 * notice, this list of conditions and the following disclaimer. 13 * 2. Redistributions in binary form must reproduce the above copyright 14 * notice, this list of conditions and the following disclaimer in 15 * the documentation and/or other materials provided with the 16 * distribution. 17 * 3. Neither the name of The DragonFly Project nor the names of its 18 * contributors may be used to endorse or promote products derived 19 * from this software without specific, prior written permission. 20 * 21 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS 22 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 23 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS 24 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE 25 * COPYRIGHT HOLDERS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, 26 * INCIDENTAL, SPECIAL, EXEMPLARY OR CONSEQUENTIAL DAMAGES (INCLUDING, 27 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; 28 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED 29 * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, 30 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT 31 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 32 * SUCH DAMAGE. 33 * 34 * $DragonFly: src/sbin/hammer/cache.c,v 1.5 2008/05/16 18:39:03 dillon Exp $ 35 */ 36 37 #include <sys/types.h> 38 #include <assert.h> 39 #include <stdio.h> 40 #include <stdlib.h> 41 #include <stdarg.h> 42 #include <string.h> 43 #include <unistd.h> 44 #include <err.h> 45 #include <fcntl.h> 46 #include "hammer_util.h" 47 48 static int CacheUse; 49 static int CacheMax = 16 * 1024 * 1024; 50 static int NCache; 51 static TAILQ_HEAD(, cache_info) CacheList = TAILQ_HEAD_INITIALIZER(CacheList); 52 53 void 54 hammer_cache_set(int bytes) 55 { 56 CacheMax = bytes; 57 } 58 59 void 60 hammer_cache_add(struct cache_info *cache, enum cache_type type) 61 { 62 TAILQ_INSERT_HEAD(&CacheList, cache, entry); 63 cache->type = type; 64 CacheUse += HAMMER_BUFSIZE; 65 ++NCache; 66 } 67 68 void 69 hammer_cache_del(struct cache_info *cache) 70 { 71 TAILQ_REMOVE(&CacheList, cache, entry); 72 CacheUse -= HAMMER_BUFSIZE; 73 --NCache; 74 } 75 76 void 77 hammer_cache_used(struct cache_info *cache) 78 { 79 TAILQ_REMOVE(&CacheList, cache, entry); 80 TAILQ_INSERT_TAIL(&CacheList, cache, entry); 81 } 82 83 void 84 hammer_cache_flush(void) 85 { 86 struct cache_info *cache; 87 int target; 88 int count = 0; 89 int ncache = NCache; 90 91 if (CacheUse >= CacheMax) { 92 target = CacheMax / 2; 93 while ((cache = TAILQ_FIRST(&CacheList)) != NULL) { 94 ++count; 95 if (cache->refs) { 96 TAILQ_REMOVE(&CacheList, cache, entry); 97 TAILQ_INSERT_TAIL(&CacheList, cache, entry); 98 continue; 99 } 100 if (count >= NCache) { 101 CacheMax += 8 * 1024 * 1024; 102 target = CacheMax / 2; 103 count = 0; 104 } 105 cache->refs = 1; 106 cache->delete = 1; 107 --count; 108 109 switch(cache->type) { 110 case ISVOLUME: 111 rel_volume(cache->u.volume); 112 break; 113 case ISBUFFER: 114 rel_buffer(cache->u.buffer); 115 break; 116 default: 117 errx(1, "hammer_cache_flush: unknown type: %d", 118 (int)cache->type); 119 /* not reached */ 120 break; 121 } 122 /* structure was freed */ 123 if (CacheUse < target) 124 break; 125 } 126 if (DebugOpt) 127 fprintf(stderr, "hammer_cache_flush: free %d/%d cache\n", 128 ncache - NCache, ncache); 129 } 130 } 131 132