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-rw-r--r--contrib/bind9/lib/isc/stats.c326
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diff --git a/contrib/bind9/lib/isc/stats.c b/contrib/bind9/lib/isc/stats.c
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+/*
+ * Copyright (C) 2009 Internet Systems Consortium, Inc. ("ISC")
+ *
+ * Permission to use, copy, modify, and/or distribute this software for any
+ * purpose with or without fee is hereby granted, provided that the above
+ * copyright notice and this permission notice appear in all copies.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS" AND ISC DISCLAIMS ALL WARRANTIES WITH
+ * REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY
+ * AND FITNESS. IN NO EVENT SHALL ISC BE LIABLE FOR ANY SPECIAL, DIRECT,
+ * INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM
+ * LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE
+ * OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
+ * PERFORMANCE OF THIS SOFTWARE.
+ */
+
+/* $Id: stats.c,v 1.3.6.2 2009/01/29 23:47:44 tbox Exp $ */
+
+/*! \file */
+
+#include <config.h>
+
+#include <string.h>
+
+#include <isc/atomic.h>
+#include <isc/buffer.h>
+#include <isc/magic.h>
+#include <isc/mem.h>
+#include <isc/platform.h>
+#include <isc/print.h>
+#include <isc/rwlock.h>
+#include <isc/stats.h>
+#include <isc/util.h>
+
+#define ISC_STATS_MAGIC ISC_MAGIC('S', 't', 'a', 't')
+#define ISC_STATS_VALID(x) ISC_MAGIC_VALID(x, ISC_STATS_MAGIC)
+
+#ifndef ISC_STATS_USEMULTIFIELDS
+#if defined(ISC_RWLOCK_USEATOMIC) && defined(ISC_PLATFORM_HAVEXADD) && !defined(ISC_PLATFORM_HAVEXADDQ)
+#define ISC_STATS_USEMULTIFIELDS 1
+#else
+#define ISC_STATS_USEMULTIFIELDS 0
+#endif
+#endif /* ISC_STATS_USEMULTIFIELDS */
+
+#if ISC_STATS_USEMULTIFIELDS
+typedef struct {
+ isc_uint32_t hi;
+ isc_uint32_t lo;
+} isc_stat_t;
+#else
+typedef isc_uint64_t isc_stat_t;
+#endif
+
+struct isc_stats {
+ /*% Unlocked */
+ unsigned int magic;
+ isc_mem_t *mctx;
+ int ncounters;
+
+ isc_mutex_t lock;
+ unsigned int references; /* locked by lock */
+
+ /*%
+ * Locked by counterlock or unlocked if efficient rwlock is not
+ * available.
+ */
+#ifdef ISC_RWLOCK_USEATOMIC
+ isc_rwlock_t counterlock;
+#endif
+ isc_stat_t *counters;
+
+ /*%
+ * We don't want to lock the counters while we are dumping, so we first
+ * copy the current counter values into a local array. This buffer
+ * will be used as the copy destination. It's allocated on creation
+ * of the stats structure so that the dump operation won't fail due
+ * to memory allocation failure.
+ * XXX: this approach is weird for non-threaded build because the
+ * additional memory and the copy overhead could be avoided. We prefer
+ * simplicity here, however, under the assumption that this function
+ * should be only rarely called.
+ */
+ isc_uint64_t *copiedcounters;
+};
+
+static isc_result_t
+create_stats(isc_mem_t *mctx, int ncounters, isc_stats_t **statsp) {
+ isc_stats_t *stats;
+ isc_result_t result = ISC_R_SUCCESS;
+
+ REQUIRE(statsp != NULL && *statsp == NULL);
+
+ stats = isc_mem_get(mctx, sizeof(*stats));
+ if (stats == NULL)
+ return (ISC_R_NOMEMORY);
+
+ result = isc_mutex_init(&stats->lock);
+ if (result != ISC_R_SUCCESS)
+ goto clean_stats;
+
+ stats->counters = isc_mem_get(mctx, sizeof(isc_stat_t) * ncounters);
+ if (stats->counters == NULL) {
+ result = ISC_R_NOMEMORY;
+ goto clean_mutex;
+ }
+ stats->copiedcounters = isc_mem_get(mctx,
+ sizeof(isc_uint64_t) * ncounters);
+ if (stats->copiedcounters == NULL) {
+ result = ISC_R_NOMEMORY;
+ goto clean_counters;
+ }
+
+#ifdef ISC_RWLOCK_USEATOMIC
+ result = isc_rwlock_init(&stats->counterlock, 0, 0);
+ if (result != ISC_R_SUCCESS)
+ goto clean_copiedcounters;
+#endif
+
+ stats->references = 1;
+ memset(stats->counters, 0, sizeof(isc_stat_t) * ncounters);
+ stats->mctx = NULL;
+ isc_mem_attach(mctx, &stats->mctx);
+ stats->ncounters = ncounters;
+ stats->magic = ISC_STATS_MAGIC;
+
+ *statsp = stats;
+
+ return (result);
+
+clean_counters:
+ isc_mem_put(mctx, stats->counters, sizeof(isc_stat_t) * ncounters);
+
+#ifdef ISC_RWLOCK_USEATOMIC
+clean_copiedcounters:
+ isc_mem_put(mctx, stats->copiedcounters,
+ sizeof(isc_stat_t) * ncounters);
+#endif
+
+clean_mutex:
+ DESTROYLOCK(&stats->lock);
+
+clean_stats:
+ isc_mem_put(mctx, stats, sizeof(*stats));
+
+ return (result);
+}
+
+void
+isc_stats_attach(isc_stats_t *stats, isc_stats_t **statsp) {
+ REQUIRE(ISC_STATS_VALID(stats));
+ REQUIRE(statsp != NULL && *statsp == NULL);
+
+ LOCK(&stats->lock);
+ stats->references++;
+ UNLOCK(&stats->lock);
+
+ *statsp = stats;
+}
+
+void
+isc_stats_detach(isc_stats_t **statsp) {
+ isc_stats_t *stats;
+
+ REQUIRE(statsp != NULL && ISC_STATS_VALID(*statsp));
+
+ stats = *statsp;
+ *statsp = NULL;
+
+ LOCK(&stats->lock);
+ stats->references--;
+ UNLOCK(&stats->lock);
+
+ if (stats->references == 0) {
+ isc_mem_put(stats->mctx, stats->copiedcounters,
+ sizeof(isc_stat_t) * stats->ncounters);
+ isc_mem_put(stats->mctx, stats->counters,
+ sizeof(isc_stat_t) * stats->ncounters);
+ DESTROYLOCK(&stats->lock);
+#ifdef ISC_RWLOCK_USEATOMIC
+ isc_rwlock_destroy(&stats->counterlock);
+#endif
+ isc_mem_putanddetach(&stats->mctx, stats, sizeof(*stats));
+ }
+}
+
+int
+isc_stats_ncounters(isc_stats_t *stats) {
+ REQUIRE(ISC_STATS_VALID(stats));
+
+ return (stats->ncounters);
+}
+
+static inline void
+incrementcounter(isc_stats_t *stats, int counter) {
+ isc_int32_t prev;
+
+#ifdef ISC_RWLOCK_USEATOMIC
+ /*
+ * We use a "read" lock to prevent other threads from reading the
+ * counter while we "writing" a counter field. The write access itself
+ * is protected by the atomic operation.
+ */
+ isc_rwlock_lock(&stats->counterlock, isc_rwlocktype_read);
+#endif
+
+#if ISC_STATS_USEMULTIFIELDS
+ prev = isc_atomic_xadd((isc_int32_t *)&stats->counters[counter].lo, 1);
+ /*
+ * If the lower 32-bit field overflows, increment the higher field.
+ * Note that it's *theoretically* possible that the lower field
+ * overlaps again before the higher field is incremented. It doesn't
+ * matter, however, because we don't read the value until
+ * isc_stats_copy() is called where the whole process is protected
+ * by the write (exclusive) lock.
+ */
+ if (prev == (isc_int32_t)0xffffffff)
+ isc_atomic_xadd((isc_int32_t *)&stats->counters[counter].hi, 1);
+#elif defined(ISC_PLATFORM_HAVEXADDQ)
+ UNUSED(prev);
+ isc_atomic_xaddq((isc_int64_t *)&stats->counters[counter], 1);
+#else
+ UNUSED(prev);
+ stats->counters[counter]++;
+#endif
+
+#ifdef ISC_RWLOCK_USEATOMIC
+ isc_rwlock_unlock(&stats->counterlock, isc_rwlocktype_read);
+#endif
+}
+
+static inline void
+decrementcounter(isc_stats_t *stats, int counter) {
+ isc_int32_t prev;
+
+#ifdef ISC_RWLOCK_USEATOMIC
+ isc_rwlock_lock(&stats->counterlock, isc_rwlocktype_read);
+#endif
+
+#if ISC_STATS_USEMULTIFIELDS
+ prev = isc_atomic_xadd((isc_int32_t *)&stats->counters[counter].lo, -1);
+ if (prev == 0)
+ isc_atomic_xadd((isc_int32_t *)&stats->counters[counter].hi,
+ -1);
+#elif defined(ISC_PLATFORM_HAVEXADDQ)
+ UNUSED(prev);
+ isc_atomic_xaddq((isc_int64_t *)&stats->counters[counter], -1);
+#else
+ UNUSED(prev);
+ stats->counters[counter]--;
+#endif
+
+#ifdef ISC_RWLOCK_USEATOMIC
+ isc_rwlock_unlock(&stats->counterlock, isc_rwlocktype_read);
+#endif
+}
+
+static void
+copy_counters(isc_stats_t *stats) {
+ int i;
+
+#ifdef ISC_RWLOCK_USEATOMIC
+ /*
+ * We use a "write" lock before "reading" the statistics counters as
+ * an exclusive lock.
+ */
+ isc_rwlock_lock(&stats->counterlock, isc_rwlocktype_write);
+#endif
+
+#if ISC_STATS_USEMULTIFIELDS
+ for (i = 0; i < stats->ncounters; i++) {
+ stats->copiedcounters[i] =
+ (isc_uint64_t)(stats->counters[i].hi) << 32 |
+ stats->counters[i].lo;
+ }
+#else
+ UNUSED(i);
+ memcpy(stats->copiedcounters, stats->counters,
+ stats->ncounters * sizeof(isc_stat_t));
+#endif
+
+#ifdef ISC_RWLOCK_USEATOMIC
+ isc_rwlock_unlock(&stats->counterlock, isc_rwlocktype_write);
+#endif
+}
+
+isc_result_t
+isc_stats_create(isc_mem_t *mctx, isc_stats_t **statsp, int ncounters) {
+ REQUIRE(statsp != NULL && *statsp == NULL);
+
+ return (create_stats(mctx, ncounters, statsp));
+}
+
+void
+isc_stats_increment(isc_stats_t *stats, isc_statscounter_t counter) {
+ REQUIRE(ISC_STATS_VALID(stats));
+ REQUIRE(counter < stats->ncounters);
+
+ incrementcounter(stats, (int)counter);
+}
+
+void
+isc_stats_decrement(isc_stats_t *stats, isc_statscounter_t counter) {
+ REQUIRE(ISC_STATS_VALID(stats));
+ REQUIRE(counter < stats->ncounters);
+
+ decrementcounter(stats, (int)counter);
+}
+
+void
+isc_stats_dump(isc_stats_t *stats, isc_stats_dumper_t dump_fn,
+ void *arg, unsigned int options)
+{
+ int i;
+
+ REQUIRE(ISC_STATS_VALID(stats));
+
+ copy_counters(stats);
+
+ for (i = 0; i < stats->ncounters; i++) {
+ if ((options & ISC_STATSDUMP_VERBOSE) == 0 &&
+ stats->copiedcounters[i] == 0)
+ continue;
+ dump_fn((isc_statscounter_t)i, stats->copiedcounters[i], arg);
+ }
+}
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