cavis/libnd4j/include/helpers/SimpleReadWriteLock.h

61 lines
1.9 KiB
C++

/*******************************************************************************
* Copyright (c) 2015-2018 Skymind, Inc.
*
* This program and the accompanying materials are made available under the
* terms of the Apache License, Version 2.0 which is available 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.
*
* SPDX-License-Identifier: Apache-2.0
******************************************************************************/
//
// Created by raver on 8/29/2018.
//
#ifndef LIBND4J_READWRITELOCK_H
#define LIBND4J_READWRITELOCK_H
#include <atomic>
#include <mutex>
#include <system/dll.h>
/**
* This class provides PRIMITIVE read-write lock, and should NOT be used outside of GraphServer due to its inefficiency.
* However, since GraphServer isn't supposed to have Reads/Writes ration even close to 1.0, it'll work just fine.
*
* Basic idea: write lock won't be obtained before all read requests served
*/
namespace sd {
class ND4J_EXPORT SimpleReadWriteLock {
private:
std::atomic<unsigned long long int> _read_locks;
std::atomic<unsigned long long int> _write_locks;
std::mutex _mutex;
public:
explicit SimpleReadWriteLock();
SimpleReadWriteLock(const SimpleReadWriteLock& other);
~SimpleReadWriteLock() = default;
// read lock
void lockRead();
void unlockRead();
// write lock
void lockWrite();
void unlockWrite();
SimpleReadWriteLock& operator= ( const SimpleReadWriteLock &other);
};
}
#endif //DEV_TESTS_READWRITELOCK_H