1 /* $NetBSD: stats.c,v 1.10 2022/09/23 12:15:33 christos Exp $ */
2
3 /*
4 * Copyright (C) Internet Systems Consortium, Inc. ("ISC")
5 *
6 * SPDX-License-Identifier: MPL-2.0
7 *
8 * This Source Code Form is subject to the terms of the Mozilla Public
9 * License, v. 2.0. If a copy of the MPL was not distributed with this
10 * file, you can obtain one at https://mozilla.org/MPL/2.0/.
11 *
12 * See the COPYRIGHT file distributed with this work for additional
13 * information regarding copyright ownership.
14 */
15
16 /*! \file */
17
18 #include <inttypes.h>
19 #include <string.h>
20
21 #include <isc/atomic.h>
22 #include <isc/buffer.h>
23 #include <isc/magic.h>
24 #include <isc/mem.h>
25 #include <isc/platform.h>
26 #include <isc/print.h>
27 #include <isc/refcount.h>
28 #include <isc/stats.h>
29 #include <isc/util.h>
30
31 #define ISC_STATS_MAGIC ISC_MAGIC('S', 't', 'a', 't')
32 #define ISC_STATS_VALID(x) ISC_MAGIC_VALID(x, ISC_STATS_MAGIC)
33
34 #if (defined(_WIN32) && !defined(_WIN64)) || !defined(_LP64)
35 typedef atomic_int_fast32_t isc__atomic_statcounter_t;
36 #else /* if defined(_WIN32) && !defined(_WIN64) */
37 typedef atomic_int_fast64_t isc__atomic_statcounter_t;
38 #endif /* if defined(_WIN32) && !defined(_WIN64) */
39
40 struct isc_stats {
41 unsigned int magic;
42 isc_mem_t *mctx;
43 isc_refcount_t references;
44 int ncounters;
45 isc__atomic_statcounter_t *counters;
46 };
47
48 static isc_result_t
create_stats(isc_mem_t * mctx,int ncounters,isc_stats_t ** statsp)49 create_stats(isc_mem_t *mctx, int ncounters, isc_stats_t **statsp) {
50 isc_stats_t *stats;
51 size_t counters_alloc_size;
52
53 REQUIRE(statsp != NULL && *statsp == NULL);
54
55 stats = isc_mem_get(mctx, sizeof(*stats));
56 counters_alloc_size = sizeof(isc__atomic_statcounter_t) * ncounters;
57 stats->counters = isc_mem_get(mctx, counters_alloc_size);
58 isc_refcount_init(&stats->references, 1);
59 for (int i = 0; i < ncounters; i++) {
60 atomic_init(&stats->counters[i], 0);
61 }
62 stats->mctx = NULL;
63 isc_mem_attach(mctx, &stats->mctx);
64 stats->ncounters = ncounters;
65 stats->magic = ISC_STATS_MAGIC;
66 *statsp = stats;
67
68 return (ISC_R_SUCCESS);
69 }
70
71 void
isc_stats_attach(isc_stats_t * stats,isc_stats_t ** statsp)72 isc_stats_attach(isc_stats_t *stats, isc_stats_t **statsp) {
73 REQUIRE(ISC_STATS_VALID(stats));
74 REQUIRE(statsp != NULL && *statsp == NULL);
75
76 isc_refcount_increment(&stats->references);
77 *statsp = stats;
78 }
79
80 void
isc_stats_detach(isc_stats_t ** statsp)81 isc_stats_detach(isc_stats_t **statsp) {
82 isc_stats_t *stats;
83
84 REQUIRE(statsp != NULL && ISC_STATS_VALID(*statsp));
85
86 stats = *statsp;
87 *statsp = NULL;
88
89 if (isc_refcount_decrement(&stats->references) == 1) {
90 isc_refcount_destroy(&stats->references);
91 isc_mem_put(stats->mctx, stats->counters,
92 sizeof(isc__atomic_statcounter_t) *
93 stats->ncounters);
94 isc_mem_putanddetach(&stats->mctx, stats, sizeof(*stats));
95 }
96 }
97
98 int
isc_stats_ncounters(isc_stats_t * stats)99 isc_stats_ncounters(isc_stats_t *stats) {
100 REQUIRE(ISC_STATS_VALID(stats));
101
102 return (stats->ncounters);
103 }
104
105 isc_result_t
isc_stats_create(isc_mem_t * mctx,isc_stats_t ** statsp,int ncounters)106 isc_stats_create(isc_mem_t *mctx, isc_stats_t **statsp, int ncounters) {
107 REQUIRE(statsp != NULL && *statsp == NULL);
108
109 return (create_stats(mctx, ncounters, statsp));
110 }
111
112 void
isc_stats_increment(isc_stats_t * stats,isc_statscounter_t counter)113 isc_stats_increment(isc_stats_t *stats, isc_statscounter_t counter) {
114 REQUIRE(ISC_STATS_VALID(stats));
115 REQUIRE(counter < stats->ncounters);
116
117 atomic_fetch_add_relaxed(&stats->counters[counter], 1);
118 }
119
120 void
isc_stats_decrement(isc_stats_t * stats,isc_statscounter_t counter)121 isc_stats_decrement(isc_stats_t *stats, isc_statscounter_t counter) {
122 REQUIRE(ISC_STATS_VALID(stats));
123 REQUIRE(counter < stats->ncounters);
124 atomic_fetch_sub_release(&stats->counters[counter], 1);
125 }
126
127 void
isc_stats_dump(isc_stats_t * stats,isc_stats_dumper_t dump_fn,void * arg,unsigned int options)128 isc_stats_dump(isc_stats_t *stats, isc_stats_dumper_t dump_fn, void *arg,
129 unsigned int options) {
130 int i;
131
132 REQUIRE(ISC_STATS_VALID(stats));
133
134 for (i = 0; i < stats->ncounters; i++) {
135 uint32_t counter = atomic_load_acquire(&stats->counters[i]);
136 if ((options & ISC_STATSDUMP_VERBOSE) == 0 && counter == 0) {
137 continue;
138 }
139 dump_fn((isc_statscounter_t)i, counter, arg);
140 }
141 }
142
143 void
isc_stats_set(isc_stats_t * stats,uint64_t val,isc_statscounter_t counter)144 isc_stats_set(isc_stats_t *stats, uint64_t val, isc_statscounter_t counter) {
145 REQUIRE(ISC_STATS_VALID(stats));
146 REQUIRE(counter < stats->ncounters);
147
148 atomic_store_release(&stats->counters[counter], val);
149 }
150
151 void
isc_stats_update_if_greater(isc_stats_t * stats,isc_statscounter_t counter,isc_statscounter_t value)152 isc_stats_update_if_greater(isc_stats_t *stats, isc_statscounter_t counter,
153 isc_statscounter_t value) {
154 REQUIRE(ISC_STATS_VALID(stats));
155 REQUIRE(counter < stats->ncounters);
156
157 isc_statscounter_t curr_value =
158 atomic_load_acquire(&stats->counters[counter]);
159 do {
160 if (curr_value >= value) {
161 break;
162 }
163 } while (!atomic_compare_exchange_weak_acq_rel(
164 &stats->counters[counter], &curr_value, value));
165 }
166
167 isc_statscounter_t
isc_stats_get_counter(isc_stats_t * stats,isc_statscounter_t counter)168 isc_stats_get_counter(isc_stats_t *stats, isc_statscounter_t counter) {
169 REQUIRE(ISC_STATS_VALID(stats));
170 REQUIRE(counter < stats->ncounters);
171
172 return (atomic_load_acquire(&stats->counters[counter]));
173 }
174
175 void
isc_stats_resize(isc_stats_t ** statsp,int ncounters)176 isc_stats_resize(isc_stats_t **statsp, int ncounters) {
177 isc_stats_t *stats;
178 size_t counters_alloc_size;
179 isc__atomic_statcounter_t *newcounters;
180
181 REQUIRE(statsp != NULL && *statsp != NULL);
182 REQUIRE(ISC_STATS_VALID(*statsp));
183 REQUIRE(ncounters > 0);
184
185 stats = *statsp;
186 if (stats->ncounters >= ncounters) {
187 /* We already have enough counters. */
188 return;
189 }
190
191 /* Grow number of counters. */
192 counters_alloc_size = sizeof(isc__atomic_statcounter_t) * ncounters;
193 newcounters = isc_mem_get(stats->mctx, counters_alloc_size);
194 for (int i = 0; i < ncounters; i++) {
195 atomic_init(&newcounters[i], 0);
196 }
197 for (int i = 0; i < stats->ncounters; i++) {
198 uint32_t counter = atomic_load_acquire(&stats->counters[i]);
199 atomic_store_release(&newcounters[i], counter);
200 }
201 isc_mem_put(stats->mctx, stats->counters,
202 sizeof(isc__atomic_statcounter_t) * stats->ncounters);
203 stats->counters = newcounters;
204 stats->ncounters = ncounters;
205 }
206