/contrib/bind9/lib/isc/stats.c
https://bitbucket.org/freebsd/freebsd-head/ · C · 326 lines · 218 code · 58 blank · 50 comment · 34 complexity · c8ffd7052b2552c54ced664664e3b1fa MD5 · raw file
- /*
- * Copyright (C) 2009, 2012 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.
- */
- /* $Id$ */
- /*! \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);
- }
- }