AsymmetricMemoryBarrier.h

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/*
 * Copyright 2016-present Facebook, 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.
 */

#pragma once

#include <atomic>

#include <folly/portability/Asm.h>

namespace folly {

enum class AMBFlags {
  NORMAL,
  EXPEDITED,
};

FOLLY_ALWAYS_INLINE void asymmetricLightBarrier() {
  if (kIsLinux) {
    asm_volatile_memory();
  } else {
    std::atomic_thread_fence(std::memory_order_seq_cst);
  }
}

void asymmetricHeavyBarrier(AMBFlags flags = AMBFlags::EXPEDITED);
} // namespace folly