YugabyteDB (2.13.0.0-b42, bfc6a6643e7399ac8a0e81d06a3ee6d6571b33ab)

// 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.

//

#ifndef YB_SERVER_TOTAL_MEM_WATCHER_H

#define YB_SERVER_TOTAL_MEM_WATCHER_H

#include <functional>

#include <memory>

#include "yb/gutil/macros.h"

#include "yb/util/status_fwd.h"

namespace yb {

namespace server {

// Allows to monitor total memory usage (resident set size, or RSS) of the current process as seen

// by the operating system, and decide whether the process should exit if it allocates too much

// memory.

//

// This class is not thread-safe.

class TotalMemWatcher {

 public:

  virtual ~TotalMemWatcher();

  // Re-check the total memory usage and populate the internal state of this watcher object.

  virtual CHECKED_STATUS Check() = 0;

  // Determines whether the program should terminate based on the most recent check. Returns a

  // non-empty string with the termination reason if the program should terminate, or or an empty

  // string if it should not.

  virtual std::string GetTerminationExplanation() { return std::string(); }

  // Returns a human-readable representation of memory usage details to be printed before program

  // terminates due to exceeding the memory limit.

  virtual std::string GetMemoryUsageDetails() { return "N/A"; }

  static std::unique_ptr<TotalMemWatcher> Create();

  // Enters an infinite loop monitoring memory usage. Exits from the loop if the memory usage limit

  // has been exceeded. Uses the provided functions to initiate server shutdown and check if

  // shutdown has completed.

  void MemoryMonitoringLoop(std::function<void()> shutdown_fn,

                            std::function<bool()> is_shutdown_finished_fn);

 protected:

  TotalMemWatcher();

  size_t rss_termination_limit_bytes_;

 private:

  DISALLOW_COPY_AND_ASSIGN(TotalMemWatcher);

};

}  // namespace server

}  // namespace yb

#endif  // YB_SERVER_TOTAL_MEM_WATCHER_H