| // Licensed to the Apache Software Foundation (ASF) under one |
| // or more contributor license agreements. See the NOTICE file |
| // distributed with this work for additional information |
| // regarding copyright ownership. The ASF licenses this file |
| // to you 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 |
| // |
| // http://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 <glog/logging.h> |
| |
| #include "kudu/util/resettable_heartbeater.h" |
| |
| #include "kudu/gutil/ref_counted.h" |
| #include "kudu/gutil/strings/substitute.h" |
| #include "kudu/util/countdown_latch.h" |
| #include "kudu/util/locks.h" |
| #include "kudu/util/random.h" |
| #include "kudu/util/status.h" |
| #include "kudu/util/thread.h" |
| |
| namespace kudu { |
| using std::string; |
| |
| class ResettableHeartbeaterThread { |
| public: |
| ResettableHeartbeaterThread(std::string name, MonoDelta period, |
| HeartbeatFunction function); |
| |
| Status Start(); |
| Status Stop(); |
| void Reset(); |
| |
| private: |
| void RunThread(); |
| bool IsCurrentThread() const; |
| |
| const string name_; |
| |
| // The heartbeat period. |
| const MonoDelta period_; |
| |
| // The function to call to perform the heartbeat |
| const HeartbeatFunction function_; |
| |
| // The actual running thread (NULL before it is started) |
| scoped_refptr<kudu::Thread> thread_; |
| |
| CountDownLatch run_latch_; |
| |
| // Whether the heartbeater should shutdown. |
| bool shutdown_; |
| |
| // lock that protects access to 'shutdown_' and to 'run_latch_' |
| // Reset() method. |
| mutable simple_spinlock lock_; |
| DISALLOW_COPY_AND_ASSIGN(ResettableHeartbeaterThread); |
| }; |
| |
| ResettableHeartbeater::ResettableHeartbeater(const std::string& name, |
| MonoDelta period, |
| HeartbeatFunction function) |
| : thread_(new ResettableHeartbeaterThread(name, period, function)) { |
| } |
| |
| Status ResettableHeartbeater::Start() { |
| return thread_->Start(); |
| } |
| |
| Status ResettableHeartbeater::Stop() { |
| return thread_->Stop(); |
| } |
| void ResettableHeartbeater::Reset() { |
| thread_->Reset(); |
| } |
| |
| ResettableHeartbeater::~ResettableHeartbeater() { |
| WARN_NOT_OK(Stop(), "Unable to stop heartbeater thread"); |
| } |
| |
| ResettableHeartbeaterThread::ResettableHeartbeaterThread( |
| std::string name, MonoDelta period, HeartbeatFunction function) |
| : name_(std::move(name)), |
| period_(std::move(period)), |
| function_(std::move(function)), |
| run_latch_(0), |
| shutdown_(false) {} |
| |
| void ResettableHeartbeaterThread::RunThread() { |
| CHECK(IsCurrentThread()); |
| VLOG(1) << "Heartbeater: " << name_ << " thread starting"; |
| |
| bool prev_reset_was_manual = false; |
| Random rng(random()); |
| while (true) { |
| MonoDelta wait_period = period_; |
| if (prev_reset_was_manual) { |
| // When the caller does a manual reset, we randomize the subsequent wait |
| // timeout between period_/2 and period_. This builds in some jitter so |
| // multiple tablets on the same TS don't end up heartbeating in lockstep. |
| int64_t half_period_ms = period_.ToMilliseconds() / 2; |
| wait_period = MonoDelta::FromMilliseconds( |
| half_period_ms + |
| rng.NextDoubleFraction() * half_period_ms); |
| prev_reset_was_manual = false; |
| } |
| if (run_latch_.WaitFor(wait_period)) { |
| // CountDownLatch reached 0 -- this means there was a manual reset. |
| prev_reset_was_manual = true; |
| lock_guard<simple_spinlock> lock(&lock_); |
| // check if we were told to shutdown |
| if (shutdown_) { |
| // Latch fired -- exit loop |
| VLOG(1) << "Heartbeater: " << name_ << " thread finished"; |
| return; |
| } else { |
| // otherwise it's just a reset, reset the latch |
| // and continue; |
| run_latch_.Reset(1); |
| continue; |
| } |
| } |
| |
| Status s = function_(); |
| if (!s.ok()) { |
| LOG(WARNING)<< "Failed to heartbeat in heartbeater: " << name_ |
| << " Status: " << s.ToString(); |
| continue; |
| } |
| } |
| } |
| |
| bool ResettableHeartbeaterThread::IsCurrentThread() const { |
| return thread_.get() == kudu::Thread::current_thread(); |
| } |
| |
| Status ResettableHeartbeaterThread::Start() { |
| CHECK(thread_ == nullptr); |
| run_latch_.Reset(1); |
| return kudu::Thread::Create("heartbeater", strings::Substitute("$0-heartbeat", name_), |
| &ResettableHeartbeaterThread::RunThread, |
| this, &thread_); |
| } |
| |
| void ResettableHeartbeaterThread::Reset() { |
| if (!thread_) { |
| return; |
| } |
| run_latch_.CountDown(); |
| } |
| |
| Status ResettableHeartbeaterThread::Stop() { |
| if (!thread_) { |
| return Status::OK(); |
| } |
| |
| { |
| lock_guard<simple_spinlock> l(&lock_); |
| if (shutdown_) { |
| return Status::OK(); |
| } |
| shutdown_ = true; |
| } |
| |
| run_latch_.CountDown(); |
| RETURN_NOT_OK(ThreadJoiner(thread_.get()).Join()); |
| return Status::OK(); |
| } |
| |
| } // namespace kudu |