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 "hammer_util.h" 38 39 static int CacheUse; 40 static int CacheMax = HAMMER_BUFSIZE * 1024; 41 static TAILQ_HEAD(, cache_info) CacheList = TAILQ_HEAD_INITIALIZER(CacheList); 42 43 int 44 hammer_parse_cache_size(const char *arg) 45 { 46 char *ptr; 47 int size = strtol(arg, &ptr, 0); 48 49 switch(*ptr) { 50 case 'm': 51 case 'M': 52 size *= 1024; 53 /* fall through */ 54 case 'k': 55 case 'K': 56 size *= 1024; 57 ++ptr; 58 break; 59 case '\0': 60 case ':': 61 /* bytes if no suffix */ 62 break; 63 default: 64 return(-1); 65 } 66 67 if (*ptr == ':') { 68 UseReadAhead = strtol(ptr + 1, NULL, 0); 69 UseReadBehind = -UseReadAhead; 70 } 71 if (size < 1024 * 1024) 72 size = 1024 * 1024; 73 if (UseReadAhead < 0) 74 return(-1); 75 if (UseReadAhead * HAMMER_BUFSIZE / size / 16) { 76 UseReadAhead = size / 16 / HAMMER_BUFSIZE; 77 UseReadBehind = -UseReadAhead; 78 } 79 80 CacheMax = size; 81 return(0); 82 } 83 84 void 85 hammer_cache_add(cache_info_t cache) 86 { 87 TAILQ_INSERT_HEAD(&CacheList, cache, entry); 88 CacheUse += HAMMER_BUFSIZE; 89 } 90 91 void 92 hammer_cache_del(cache_info_t cache) 93 { 94 TAILQ_REMOVE(&CacheList, cache, entry); 95 CacheUse -= HAMMER_BUFSIZE; 96 } 97 98 void 99 hammer_cache_used(cache_info_t cache) 100 { 101 TAILQ_REMOVE(&CacheList, cache, entry); 102 TAILQ_INSERT_TAIL(&CacheList, cache, entry); 103 } 104 105 void 106 hammer_cache_flush(void) 107 { 108 cache_info_t cache; 109 cache_info_t first = NULL; 110 int count = 0; 111 112 if (CacheUse >= CacheMax) { 113 while ((cache = TAILQ_FIRST(&CacheList)) != NULL) { 114 if (cache == first) 115 break; /* seen this ref'd before */ 116 117 if (cache->refs) { 118 if (first == NULL) 119 first = cache; 120 hammer_cache_used(cache); 121 count++; 122 continue; 123 } 124 if (count >= (CacheUse / HAMMER_BUFSIZE)) { 125 CacheMax += HAMMER_BUFSIZE * 512; 126 count = 0; 127 } 128 129 cache->refs = 1; 130 cache->delete = 1; 131 rel_buffer((buffer_info_t)cache); 132 133 if (CacheUse < CacheMax / 2) 134 break; 135 } 136 } 137 } 138 139