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Diffstat (limited to '')
-rw-r--r-- | src/rocksdb/memory/memory_usage.h | 38 |
1 files changed, 38 insertions, 0 deletions
diff --git a/src/rocksdb/memory/memory_usage.h b/src/rocksdb/memory/memory_usage.h new file mode 100644 index 000000000..76b9bd130 --- /dev/null +++ b/src/rocksdb/memory/memory_usage.h @@ -0,0 +1,38 @@ +// Copyright (c) 2011-present, Facebook, Inc. All rights reserved. +// This source code is licensed under both the GPLv2 (found in the +// COPYING file in the root directory) and Apache 2.0 License +// (found in the LICENSE.Apache file in the root directory). + +#pragma once + +#include <cstddef> +#include <unordered_map> +#ifdef USE_FOLLY +#include <folly/container/F14Map.h> +#endif + +#include "rocksdb/rocksdb_namespace.h" + +namespace ROCKSDB_NAMESPACE { + +// Helper methods to estimate memroy usage by std containers. + +template <class Key, class Value, class Hash> +size_t ApproximateMemoryUsage( + const std::unordered_map<Key, Value, Hash>& umap) { + using Map = std::unordered_map<Key, Value, Hash>; + return sizeof(umap) + + // Size of all items plus a next pointer for each item. + (sizeof(typename Map::value_type) + sizeof(void*)) * umap.size() + + // Size of hash buckets. + umap.bucket_count() * sizeof(void*); +} + +#ifdef USE_FOLLY +template <class Key, class Value, class Hash> +size_t ApproximateMemoryUsage(const folly::F14FastMap<Key, Value, Hash>& umap) { + return sizeof(umap) + umap.getAllocatedMemorySize(); +} +#endif + +} // namespace ROCKSDB_NAMESPACE |