1 files changed, 156 insertions, 0 deletions
diff --git a/src/rocksdb/utilities/persistent_cache/block_cache_tier.h b/src/rocksdb/utilities/persistent_cache/block_cache_tier.h
new file mode 100644
index 000000000..ae0c13fdb
--- /dev/null
+++ b/src/rocksdb/utilities/persistent_cache/block_cache_tier.h
@@ -0,0 +1,156 @@
+//  Copyright (c) 2013, 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
+
+#ifndef ROCKSDB_LITE
+
+#ifndef  OS_WIN
+#include <unistd.h>
+#endif // ! OS_WIN
+
+#include <atomic>
+#include <list>
+#include <memory>
+#include <set>
+#include <sstream>
+#include <stdexcept>
+#include <string>
+#include <thread>
+
+#include "rocksdb/cache.h"
+#include "rocksdb/comparator.h"
+#include "rocksdb/persistent_cache.h"
+
+#include "utilities/persistent_cache/block_cache_tier_file.h"
+#include "utilities/persistent_cache/block_cache_tier_metadata.h"
+#include "utilities/persistent_cache/persistent_cache_util.h"
+
+#include "memory/arena.h"
+#include "memtable/skiplist.h"
+#include "monitoring/histogram.h"
+#include "port/port.h"
+#include "util/coding.h"
+#include "util/crc32c.h"
+#include "util/mutexlock.h"
+
+namespace ROCKSDB_NAMESPACE {
+
+//
+// Block cache tier implementation
+//
+class BlockCacheTier : public PersistentCacheTier {
+ public:
+  explicit BlockCacheTier(const PersistentCacheConfig& opt)
+      : opt_(opt),
+        insert_ops_(static_cast<size_t>(opt_.max_write_pipeline_backlog_size)),
+        buffer_allocator_(opt.write_buffer_size, opt.write_buffer_count()),
+        writer_(this, opt_.writer_qdepth, static_cast<size_t>(opt_.writer_dispatch_size)) {
+    Info(opt_.log, "Initializing allocator. size=%d B count=%" ROCKSDB_PRIszt,
+         opt_.write_buffer_size, opt_.write_buffer_count());
+  }
+
+  virtual ~BlockCacheTier() {
+    // Close is re-entrant so we can call close even if it is already closed
+    Close();
+    assert(!insert_th_.joinable());
+  }
+
+  Status Insert(const Slice& key, const char* data, const size_t size) override;
+  Status Lookup(const Slice& key, std::unique_ptr<char[]>* data,
+                size_t* size) override;
+  Status Open() override;
+  Status Close() override;
+  bool Erase(const Slice& key) override;
+  bool Reserve(const size_t size) override;
+
+  bool IsCompressed() override { return opt_.is_compressed; }
+
+  std::string GetPrintableOptions() const override { return opt_.ToString(); }
+
+  PersistentCache::StatsType Stats() override;
+
+  void TEST_Flush() override {
+    while (insert_ops_.Size()) {
+      /* sleep override */
+      Env::Default()->SleepForMicroseconds(1000000);
+    }
+  }
+
+ private:
+  // Percentage of cache to be evicted when the cache is full
+  static const size_t kEvictPct = 10;
+  // Max attempts to insert key, value to cache in pipelined mode
+  static const size_t kMaxRetry = 3;
+
+  // Pipelined operation
+  struct InsertOp {
+    explicit InsertOp(const bool signal) : signal_(signal) {}
+    explicit InsertOp(std::string&& key, const std::string& data)
+        : key_(std::move(key)), data_(data) {}
+    ~InsertOp() {}
+
+    InsertOp() = delete;
+    InsertOp(InsertOp&& /*rhs*/) = default;
+    InsertOp& operator=(InsertOp&& rhs) = default;
+
+    // used for estimating size by bounded queue
+    size_t Size() { return data_.size() + key_.size(); }
+
+    std::string key_;
+    std::string data_;
+    bool signal_ = false;  // signal to request processing thread to exit
+  };
+
+  // entry point for insert thread
+  void InsertMain();
+  // insert implementation
+  Status InsertImpl(const Slice& key, const Slice& data);
+  // Create a new cache file
+  Status NewCacheFile();
+  // Get cache directory path
+  std::string GetCachePath() const { return opt_.path + "/cache"; }
+  // Cleanup folder
+  Status CleanupCacheFolder(const std::string& folder);
+
+  // Statistics
+  struct Statistics {
+    HistogramImpl bytes_pipelined_;
+    HistogramImpl bytes_written_;
+    HistogramImpl bytes_read_;
+    HistogramImpl read_hit_latency_;
+    HistogramImpl read_miss_latency_;
+    HistogramImpl write_latency_;
+    std::atomic<uint64_t> cache_hits_{0};
+    std::atomic<uint64_t> cache_misses_{0};
+    std::atomic<uint64_t> cache_errors_{0};
+    std::atomic<uint64_t> insert_dropped_{0};
+
+    double CacheHitPct() const {
+      const auto lookups = cache_hits_ + cache_misses_;
+      return lookups ? 100 * cache_hits_ / static_cast<double>(lookups) : 0.0;
+    }
+
+    double CacheMissPct() const {
+      const auto lookups = cache_hits_ + cache_misses_;
+      return lookups ? 100 * cache_misses_ / static_cast<double>(lookups) : 0.0;
+    }
+  };
+
+  port::RWMutex lock_;                          // Synchronization
+  const PersistentCacheConfig opt_;             // BlockCache options
+  BoundedQueue<InsertOp> insert_ops_;           // Ops waiting for insert
+  ROCKSDB_NAMESPACE::port::Thread insert_th_;   // Insert thread
+  uint32_t writer_cache_id_ = 0;                // Current cache file identifier
+  WriteableCacheFile* cache_file_ = nullptr;    // Current cache file reference
+  CacheWriteBufferAllocator buffer_allocator_;  // Buffer provider
+  ThreadedWriter writer_;                       // Writer threads
+  BlockCacheTierMetadata metadata_;             // Cache meta data manager
+  std::atomic<uint64_t> size_{0};               // Size of the cache
+  Statistics stats_;                                 // Statistics
+};
+
+}  // namespace ROCKSDB_NAMESPACE
+
+#endif