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| author | Derek Mauro <dmauro@google.com> | 2023-03-20 14:10:11 -0700 |
|---|---|---|
| committer | Copybara-Service <copybara-worker@google.com> | 2023-03-20 14:11:09 -0700 |
| commit | 396e9764cded739f595ba880b95b061051c49128 (patch) | |
| tree | 02b550c2a2b9a4fcacb4cf2555d9d8672d53248b /absl/synchronization/internal/pthread_waiter.cc | |
| parent | e5067964adcb792b7c9dbddbdcfe4d9b94079597 (diff) | |
| download | abseil-396e9764cded739f595ba880b95b061051c49128.tar.gz abseil-396e9764cded739f595ba880b95b061051c49128.tar.bz2 abseil-396e9764cded739f595ba880b95b061051c49128.zip | |
Synchronization: Refactor Waiter to allow us to write tests
Instead of being only able to test the platform Waiter implementation,
this allows us to be able to test all Waiter implementations that
build on a specific platform.
A unittest is added that tests all implementations that work for the
platform, and allows us to check that the expected one is being used
by printing the name of the selected implementation.
PiperOrigin-RevId: 518072415
Change-Id: Ie9e6fcd9d8283b4038e6f4e68a304d2adcc04b19
Diffstat (limited to 'absl/synchronization/internal/pthread_waiter.cc')
| -rw-r--r-- | absl/synchronization/internal/pthread_waiter.cc | 138 |
1 files changed, 138 insertions, 0 deletions
diff --git a/absl/synchronization/internal/pthread_waiter.cc b/absl/synchronization/internal/pthread_waiter.cc new file mode 100644 index 00000000..52587827 --- /dev/null +++ b/absl/synchronization/internal/pthread_waiter.cc @@ -0,0 +1,138 @@ +// Copyright 2023 The Abseil Authors. +// +// Licensed under the Apache License, Version 2.0 (the "License"); +// you may not use this file except in compliance with the License. +// You may obtain a copy of the License at +// +// https://www.apache.org/licenses/LICENSE-2.0 +// +// Unless required by applicable law or agreed to in writing, software +// distributed under the License is distributed on an "AS IS" BASIS, +// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. +// See the License for the specific language governing permissions and +// limitations under the License. + +#include "absl/synchronization/internal/pthread_waiter.h" + +#ifdef ABSL_INTERNAL_HAVE_PTHREAD_WAITER + +#include <pthread.h> +#include <sys/time.h> +#include <unistd.h> + +#include <cerrno> + +#include "absl/base/config.h" +#include "absl/base/internal/raw_logging.h" +#include "absl/base/internal/thread_identity.h" +#include "absl/base/optimization.h" +#include "absl/synchronization/internal/kernel_timeout.h" + +namespace absl { +ABSL_NAMESPACE_BEGIN +namespace synchronization_internal { + +namespace { +class PthreadMutexHolder { + public: + explicit PthreadMutexHolder(pthread_mutex_t *mu) : mu_(mu) { + const int err = pthread_mutex_lock(mu_); + if (err != 0) { + ABSL_RAW_LOG(FATAL, "pthread_mutex_lock failed: %d", err); + } + } + + PthreadMutexHolder(const PthreadMutexHolder &rhs) = delete; + PthreadMutexHolder &operator=(const PthreadMutexHolder &rhs) = delete; + + ~PthreadMutexHolder() { + const int err = pthread_mutex_unlock(mu_); + if (err != 0) { + ABSL_RAW_LOG(FATAL, "pthread_mutex_unlock failed: %d", err); + } + } + + private: + pthread_mutex_t *mu_; +}; +} // namespace + +#ifdef ABSL_INTERNAL_NEED_REDUNDANT_CONSTEXPR_DECL +constexpr char PthreadWaiter::kName[]; +#endif + +PthreadWaiter::PthreadWaiter() : waiter_count_(0), wakeup_count_(0) { + const int err = pthread_mutex_init(&mu_, 0); + if (err != 0) { + ABSL_RAW_LOG(FATAL, "pthread_mutex_init failed: %d", err); + } + + const int err2 = pthread_cond_init(&cv_, 0); + if (err2 != 0) { + ABSL_RAW_LOG(FATAL, "pthread_cond_init failed: %d", err2); + } +} + +bool PthreadWaiter::Wait(KernelTimeout t) { + struct timespec abs_timeout; + if (t.has_timeout()) { + abs_timeout = t.MakeAbsTimespec(); + } + + PthreadMutexHolder h(&mu_); + ++waiter_count_; + // Loop until we find a wakeup to consume or timeout. + // Note that, since the thread ticker is just reset, we don't need to check + // whether the thread is idle on the very first pass of the loop. + bool first_pass = true; + while (wakeup_count_ == 0) { + if (!first_pass) MaybeBecomeIdle(); + // No wakeups available, time to wait. + if (!t.has_timeout()) { + const int err = pthread_cond_wait(&cv_, &mu_); + if (err != 0) { + ABSL_RAW_LOG(FATAL, "pthread_cond_wait failed: %d", err); + } + } else { + const int err = pthread_cond_timedwait(&cv_, &mu_, &abs_timeout); + if (err == ETIMEDOUT) { + --waiter_count_; + return false; + } + if (err != 0) { + ABSL_RAW_LOG(FATAL, "pthread_cond_timedwait failed: %d", err); + } + } + first_pass = false; + } + // Consume a wakeup and we're done. + --wakeup_count_; + --waiter_count_; + return true; +} + +void PthreadWaiter::Post() { + PthreadMutexHolder h(&mu_); + ++wakeup_count_; + InternalCondVarPoke(); +} + +void PthreadWaiter::Poke() { + PthreadMutexHolder h(&mu_); + InternalCondVarPoke(); +} + +void PthreadWaiter::InternalCondVarPoke() { + if (waiter_count_ != 0) { + const int err = pthread_cond_signal(&cv_); + if (ABSL_PREDICT_FALSE(err != 0)) { + ABSL_RAW_LOG(FATAL, "pthread_cond_signal failed: %d", err); + } + } +} + +} // namespace synchronization_internal +ABSL_NAMESPACE_END +} // namespace absl + +#endif // ABSL_INTERNAL_HAVE_PTHREAD_WAITER |