stats.c revision 1.2.2.3
1 /* $NetBSD: stats.c,v 1.2.2.3 2019/01/18 08:49:57 pgoyette Exp $ */ 2 3 /* 4 * Copyright (C) Internet Systems Consortium, Inc. ("ISC") 5 * 6 * This Source Code Form is subject to the terms of the Mozilla Public 7 * License, v. 2.0. If a copy of the MPL was not distributed with this 8 * file, You can obtain one at http://mozilla.org/MPL/2.0/. 9 * 10 * See the COPYRIGHT file distributed with this work for additional 11 * information regarding copyright ownership. 12 */ 13 14 15 /*! \file */ 16 17 #include <config.h> 18 19 #include <inttypes.h> 20 #include <string.h> 21 22 #include <isc/atomic.h> 23 #include <isc/buffer.h> 24 #include <isc/magic.h> 25 #include <isc/mem.h> 26 #include <isc/platform.h> 27 #include <isc/print.h> 28 #include <isc/rwlock.h> 29 #include <isc/stats.h> 30 #include <isc/util.h> 31 32 #define ISC_STATS_MAGIC ISC_MAGIC('S', 't', 'a', 't') 33 #define ISC_STATS_VALID(x) ISC_MAGIC_VALID(x, ISC_STATS_MAGIC) 34 35 #ifndef _LP64 36 typedef atomic_int_fast32_t isc_stat_t; 37 #else 38 typedef atomic_int_fast64_t isc_stat_t; 39 #endif 40 41 struct isc_stats { 42 /*% Unlocked */ 43 unsigned int magic; 44 isc_mem_t *mctx; 45 int ncounters; 46 47 isc_mutex_t lock; 48 unsigned int references; /* locked by lock */ 49 50 /*% 51 * Locked by counterlock or unlocked if efficient rwlock is not 52 * available. 53 */ 54 isc_stat_t *counters; 55 56 /*% 57 * We don't want to lock the counters while we are dumping, so we first 58 * copy the current counter values into a local array. This buffer 59 * will be used as the copy destination. It's allocated on creation 60 * of the stats structure so that the dump operation won't fail due 61 * to memory allocation failure. 62 * XXX: this approach is weird for non-threaded build because the 63 * additional memory and the copy overhead could be avoided. We prefer 64 * simplicity here, however, under the assumption that this function 65 * should be only rarely called. 66 */ 67 uint64_t *copiedcounters; 68 }; 69 70 static isc_result_t 71 create_stats(isc_mem_t *mctx, int ncounters, isc_stats_t **statsp) { 72 isc_stats_t *stats; 73 isc_result_t result = ISC_R_SUCCESS; 74 75 REQUIRE(statsp != NULL && *statsp == NULL); 76 77 stats = isc_mem_get(mctx, sizeof(*stats)); 78 if (stats == NULL) 79 return (ISC_R_NOMEMORY); 80 81 isc_mutex_init(&stats->lock); 82 83 stats->counters = isc_mem_get(mctx, sizeof(isc_stat_t) * ncounters); 84 if (stats->counters == NULL) { 85 result = ISC_R_NOMEMORY; 86 goto clean_mutex; 87 } 88 stats->copiedcounters = isc_mem_get(mctx, 89 sizeof(uint64_t) * ncounters); 90 if (stats->copiedcounters == NULL) { 91 result = ISC_R_NOMEMORY; 92 goto clean_counters; 93 } 94 95 stats->references = 1; 96 memset(stats->counters, 0, sizeof(isc_stat_t) * ncounters); 97 stats->mctx = NULL; 98 isc_mem_attach(mctx, &stats->mctx); 99 stats->ncounters = ncounters; 100 stats->magic = ISC_STATS_MAGIC; 101 102 *statsp = stats; 103 104 return (result); 105 106 clean_counters: 107 isc_mem_put(mctx, stats->counters, sizeof(isc_stat_t) * ncounters); 108 109 clean_mutex: 110 isc_mutex_destroy(&stats->lock); 111 isc_mem_put(mctx, stats, sizeof(*stats)); 112 113 return (result); 114 } 115 116 void 117 isc_stats_attach(isc_stats_t *stats, isc_stats_t **statsp) { 118 REQUIRE(ISC_STATS_VALID(stats)); 119 REQUIRE(statsp != NULL && *statsp == NULL); 120 121 LOCK(&stats->lock); 122 stats->references++; 123 UNLOCK(&stats->lock); 124 125 *statsp = stats; 126 } 127 128 void 129 isc_stats_detach(isc_stats_t **statsp) { 130 isc_stats_t *stats; 131 132 REQUIRE(statsp != NULL && ISC_STATS_VALID(*statsp)); 133 134 stats = *statsp; 135 *statsp = NULL; 136 137 LOCK(&stats->lock); 138 stats->references--; 139 140 if (stats->references == 0) { 141 isc_mem_put(stats->mctx, stats->copiedcounters, 142 sizeof(isc_stat_t) * stats->ncounters); 143 isc_mem_put(stats->mctx, stats->counters, 144 sizeof(isc_stat_t) * stats->ncounters); 145 UNLOCK(&stats->lock); 146 isc_mutex_destroy(&stats->lock); 147 isc_mem_putanddetach(&stats->mctx, stats, sizeof(*stats)); 148 return; 149 } 150 151 UNLOCK(&stats->lock); 152 } 153 154 int 155 isc_stats_ncounters(isc_stats_t *stats) { 156 REQUIRE(ISC_STATS_VALID(stats)); 157 158 return (stats->ncounters); 159 } 160 161 isc_result_t 162 isc_stats_create(isc_mem_t *mctx, isc_stats_t **statsp, int ncounters) { 163 REQUIRE(statsp != NULL && *statsp == NULL); 164 165 return (create_stats(mctx, ncounters, statsp)); 166 } 167 168 void 169 isc_stats_increment(isc_stats_t *stats, isc_statscounter_t counter) { 170 REQUIRE(ISC_STATS_VALID(stats)); 171 REQUIRE(counter < stats->ncounters); 172 173 atomic_fetch_add_explicit(&stats->counters[counter], 1, 174 memory_order_relaxed); 175 } 176 177 void 178 isc_stats_decrement(isc_stats_t *stats, isc_statscounter_t counter) { 179 REQUIRE(ISC_STATS_VALID(stats)); 180 REQUIRE(counter < stats->ncounters); 181 182 atomic_fetch_sub_explicit(&stats->counters[counter], 1, 183 memory_order_relaxed); 184 } 185 186 void 187 isc_stats_dump(isc_stats_t *stats, isc_stats_dumper_t dump_fn, 188 void *arg, unsigned int options) 189 { 190 int i; 191 192 REQUIRE(ISC_STATS_VALID(stats)); 193 194 for (i = 0; i < stats->ncounters; i++) { 195 stats->copiedcounters[i] = 196 atomic_load_explicit(&stats->counters[i], 197 memory_order_relaxed); 198 } 199 200 for (i = 0; i < stats->ncounters; i++) { 201 if ((options & ISC_STATSDUMP_VERBOSE) == 0 && 202 stats->copiedcounters[i] == 0) 203 continue; 204 dump_fn((isc_statscounter_t)i, stats->copiedcounters[i], arg); 205 } 206 } 207 208 void 209 isc_stats_set(isc_stats_t *stats, uint64_t val, 210 isc_statscounter_t counter) 211 { 212 REQUIRE(ISC_STATS_VALID(stats)); 213 REQUIRE(counter < stats->ncounters); 214 215 atomic_store_explicit(&stats->counters[counter], val, 216 memory_order_relaxed); 217 } 218
Indexes created Thu May 14 00:25:00 UTC 2026