BackgroundMoverStrategy.h

/*
 * Copyright (c) Meta Platforms, Inc. and affiliates.
 *
 * 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 "cachelib/allocator/Cache.h"

namespace facebook {
namespace cachelib {

struct MemoryDescriptorType {
  MemoryDescriptorType(PoolId pid, ClassId cid) : pid_(pid), cid_(cid) {}
  PoolId pid_;
  ClassId cid_;
};

// Base class for background eviction strategy.
class BackgroundMoverStrategy {
 public:
  // Calculate how many items should be moved by the background mover
  //
  // @param cache   Cache allocator that implements CacheBase
  // @param acVec   vector of memory descriptors for which batch sizes should
  //                be calculated
  //
  // @return vector of batch sizes, where each element in the vector specifies
  //         batch size for the memory descriptor in acVec
  virtual std::vector<size_t> calculateBatchSizes(
      const CacheBase& cache, std::vector<MemoryDescriptorType> acVec) = 0;

  virtual ~BackgroundMoverStrategy() = default;
};

} // namespace cachelib
} // namespace facebook