mirror of https://gitee.com/bigwinds/arangodb
115 lines
3.3 KiB
C++
115 lines
3.3 KiB
C++
////////////////////////////////////////////////////////////////////////////////
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/// DISCLAIMER
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///
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/// Copyright 2014-2016 ArangoDB GmbH, Cologne, Germany
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/// Copyright 2004-2014 triAGENS GmbH, Cologne, Germany
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///
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/// Licensed under the Apache License, Version 2.0 (the "License");
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/// you may not use this file except in compliance with the License.
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/// You may obtain a copy of the License at
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///
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/// http://www.apache.org/licenses/LICENSE-2.0
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///
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/// Unless required by applicable law or agreed to in writing, software
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/// distributed under the License is distributed on an "AS IS" BASIS,
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/// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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/// See the License for the specific language governing permissions and
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/// limitations under the License.
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///
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/// Copyright holder is ArangoDB GmbH, Cologne, Germany
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///
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/// @author Jan Steemann
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////////////////////////////////////////////////////////////////////////////////
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#ifndef ARANGOD_VOCBASE_REVISION_CACHE_CHUNK_ALLOCATOR_H
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#define ARANGOD_VOCBASE_REVISION_CACHE_CHUNK_ALLOCATOR_H 1
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#include "Basics/Common.h"
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#include "Basics/ConditionVariable.h"
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#include "Basics/Mutex.h"
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#include "Basics/ReadWriteLock.h"
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#include "Basics/Thread.h"
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#include "VocBase/RevisionCacheChunk.h"
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namespace arangodb {
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class CollectionRevisionsCache;
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class ReadCache;
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class RevisionCacheGCThread;
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class RevisionCacheChunkAllocator {
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public:
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RevisionCacheChunkAllocator() = delete;
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RevisionCacheChunkAllocator(RevisionCacheChunkAllocator const&) = delete;
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RevisionCacheChunkAllocator& operator=(RevisionCacheChunkAllocator const&) = delete;
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RevisionCacheChunkAllocator(uint32_t defaultChunkSize, uint64_t totalTargetSize);
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~RevisionCacheChunkAllocator();
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public:
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void startGcThread();
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void stopGcThread();
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void beginShutdown();
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/// @brief total number of bytes allocated by the cache
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uint64_t totalAllocated();
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/// @brief order a new chunk
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RevisionCacheChunk* orderChunk(CollectionRevisionsCache* collectionCache, uint32_t valueSize, uint32_t chunkSize);
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void returnUsed(ReadCache* cache, RevisionCacheChunk* chunk);
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void removeCollection(ReadCache* cache);
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bool garbageCollect();
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private:
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/// @brief physically delete a chunk
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void deleteChunk(RevisionCacheChunk* chunk) const;
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static constexpr uint32_t blockSize() { return 2048; }
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private:
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// lock for the lists of chunks
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arangodb::basics::ReadWriteLock _chunksLock;
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// completely (or partially unused) chunks that can still be written to
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std::vector<RevisionCacheChunk*> _freeList;
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Mutex _gcLock;
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std::unordered_map<ReadCache*, std::unordered_map<RevisionCacheChunk*, bool>> _fullChunks;
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// default size for new memory chunks
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uint32_t _defaultChunkSize;
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// total target size for all chunks
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uint64_t _totalTargetSize;
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// total number of bytes allocated by chunks
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uint64_t _totalAllocated;
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std::unique_ptr<RevisionCacheGCThread> _gcThread;
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};
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class RevisionCacheGCThread : public Thread {
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public:
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explicit RevisionCacheGCThread(RevisionCacheChunkAllocator*);
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~RevisionCacheGCThread() { shutdown(); }
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void beginShutdown() override;
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void signal();
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protected:
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void run() override;
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private:
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RevisionCacheChunkAllocator* _allocator;
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basics::ConditionVariable _condition;
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};
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} // namespace arangodb
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#endif
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