YugabyteDB (2.13.1.0-b60, 21121d69985fbf76aa6958d8f04a9bfa936293b5)

//  Copyright (c) 2011-present, Facebook, Inc.  All rights reserved.

//  This source code is licensed under the BSD-style license found in the

//  LICENSE file in the root directory of this source tree. An additional grant

//  of patent rights can be found in the PATENTS file in the same directory.

//

// The following only applies to changes made to this file as part of YugaByte development.

//

// Portions Copyright (c) YugaByte, Inc.

//

// 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

//

// 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.

//

// Copyright (c) 2011 The LevelDB Authors. All rights reserved.

// Use of this source code is governed by a BSD-style license that can be

// found in the LICENSE file. See the AUTHORS file for names of contributors.

#ifndef YB_ROCKSDB_UTIL_THREAD_POSIX_H

#define YB_ROCKSDB_UTIL_THREAD_POSIX_H

#pragma once

#include <pthread.h>

#include <string.h>

#include <cstdarg>

#include <deque>

#include "yb/gutil/ref_counted.h"

#include "yb/rocksdb/env.h"

#include "yb/rocksdb/file.h"

#include "yb/util/faststring.h"

namespace yb {

class Thread;

}

namespace rocksdb {

class ThreadPool {

 public:

  ThreadPool();

  ~ThreadPool();

  void JoinAllThreads();

  void LowerIOPriority();

  void BGThread(size_t thread_id);

  void WakeUpAllThreads();

  void IncBackgroundThreadsIfNeeded(int num);

  void SetBackgroundThreads(int num);

  void StartBGThreads();

  void Schedule(void (*function)(void* arg1), void* arg, void* tag,

                void (*unschedFunction)(void* arg));

  int UnSchedule(void* arg);

  unsigned int GetQueueLen() const {

    return queue_len_.load(std::memory_order_relaxed);

  }

  void SetHostEnv(Env* env) { env_ = env; }

  Env* GetHostEnv() { return env_; }

  // Return true if there is at least one thread needs to terminate.

  bool HasExcessiveThread() {

    return static_cast<int>(bgthreads_.size()) > total_threads_limit_;

  }

  // Return true iff the current thread is the excessive thread to terminate.

  // Always terminate the running thread that is added last, even if there are

  // more than one thread to terminate.

  bool IsLastExcessiveThread(size_t thread_id) {

    return HasExcessiveThread() && 
thread_id == bgthreads_.size() - 197
;

  }

  // Is one of the threads to terminate.

  bool IsExcessiveThread(size_t thread_id) {

    return static_cast<int>(thread_id) >= total_threads_limit_;

  }

  // Return the thread priority.

  // This would allow its member-thread to know its priority.

  Env::Priority GetThreadPriority() { return priority_; }

  // Set the thread priority.

  void SetThreadPriority(Env::Priority priority) { priority_ = priority; }

  static void PthreadCall(const char* label, int result);

 private:

  // Entry per Schedule() call

  struct BGItem {

    void* arg;

    void (*function)(void*);

    void* tag;

    void (*unschedFunction)(void*);

  };

  typedef std::deque<BGItem> BGQueue;

  pthread_mutex_t mu_;

  pthread_cond_t bgsignal_;

  int total_threads_limit_ = 1;

  std::vector<scoped_refptr<yb::Thread>> bgthreads_;

  BGQueue queue_;

  std::atomic_uint queue_len_{0};  // Queue length. Used for stats reporting

  bool exit_all_threads_ = false;

  bool low_io_priority_ = false;

  Env::Priority priority_ = static_cast<Env::Priority>(0);

  Env* env_ = nullptr;

  void SetBackgroundThreadsInternal(int num, bool allow_reduce);

};

}  // namespace rocksdb

#endif // YB_ROCKSDB_UTIL_THREAD_POSIX_H