From 483eb2f56657e8e7f419ab1a4fab8dce9ade8609 Mon Sep 17 00:00:00 2001 From: Daniel Baumann Date: Sat, 27 Apr 2024 20:24:20 +0200 Subject: Adding upstream version 14.2.21. Signed-off-by: Daniel Baumann --- src/rocksdb/cache/sharded_cache.h | 103 ++++++++++++++++++++++++++++++++++++++ 1 file changed, 103 insertions(+) create mode 100644 src/rocksdb/cache/sharded_cache.h (limited to 'src/rocksdb/cache/sharded_cache.h') diff --git a/src/rocksdb/cache/sharded_cache.h b/src/rocksdb/cache/sharded_cache.h new file mode 100644 index 00000000..920898b8 --- /dev/null +++ b/src/rocksdb/cache/sharded_cache.h @@ -0,0 +1,103 @@ +// 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). +// +// Copyright (c) 2011 The LevelDB Authors. All rights reserved. +// Use of this source code is governed by a BSD-style license that can be +// found in the LICENSE file. See the AUTHORS file for names of contributors. + +#pragma once + +#include +#include + +#include "port/port.h" +#include "rocksdb/cache.h" +#include "util/hash.h" + +namespace rocksdb { + +// Single cache shard interface. +class CacheShard { + public: + CacheShard() = default; + virtual ~CacheShard() = default; + + virtual Status Insert(const Slice& key, uint32_t hash, void* value, + size_t charge, + void (*deleter)(const Slice& key, void* value), + Cache::Handle** handle, Cache::Priority priority) = 0; + virtual Cache::Handle* Lookup(const Slice& key, uint32_t hash) = 0; + virtual bool Ref(Cache::Handle* handle) = 0; + virtual bool Release(Cache::Handle* handle, bool force_erase = false) = 0; + virtual void Erase(const Slice& key, uint32_t hash) = 0; + virtual void SetCapacity(size_t capacity) = 0; + virtual void SetStrictCapacityLimit(bool strict_capacity_limit) = 0; + virtual size_t GetUsage() const = 0; + virtual size_t GetPinnedUsage() const = 0; + virtual void ApplyToAllCacheEntries(void (*callback)(void*, size_t), + bool thread_safe) = 0; + virtual void EraseUnRefEntries() = 0; + virtual std::string GetPrintableOptions() const { return ""; } +}; + +// Generic cache interface which shards cache by hash of keys. 2^num_shard_bits +// shards will be created, with capacity split evenly to each of the shards. +// Keys are sharded by the highest num_shard_bits bits of hash value. +class ShardedCache : public Cache { + public: + ShardedCache(size_t capacity, int num_shard_bits, bool strict_capacity_limit, + std::shared_ptr memory_allocator = nullptr); + virtual ~ShardedCache() = default; + virtual const char* Name() const override = 0; + virtual CacheShard* GetShard(int shard) = 0; + virtual const CacheShard* GetShard(int shard) const = 0; + virtual void* Value(Handle* handle) override = 0; + virtual size_t GetCharge(Handle* handle) const = 0; + virtual uint32_t GetHash(Handle* handle) const = 0; + virtual void DisownData() override = 0; + + virtual void SetCapacity(size_t capacity) override; + virtual void SetStrictCapacityLimit(bool strict_capacity_limit) override; + + virtual Status Insert(const Slice& key, void* value, size_t charge, + void (*deleter)(const Slice& key, void* value), + Handle** handle, Priority priority) override; + virtual Handle* Lookup(const Slice& key, Statistics* stats) override; + virtual bool Ref(Handle* handle) override; + virtual bool Release(Handle* handle, bool force_erase = false) override; + virtual void Erase(const Slice& key) override; + virtual uint64_t NewId() override; + virtual size_t GetCapacity() const override; + virtual bool HasStrictCapacityLimit() const override; + virtual size_t GetUsage() const override; + virtual size_t GetUsage(Handle* handle) const override; + virtual size_t GetPinnedUsage() const override; + virtual void ApplyToAllCacheEntries(void (*callback)(void*, size_t), + bool thread_safe) override; + virtual void EraseUnRefEntries() override; + virtual std::string GetPrintableOptions() const override; + + int GetNumShardBits() const { return num_shard_bits_; } + + private: + static inline uint32_t HashSlice(const Slice& s) { + return static_cast(GetSliceNPHash64(s)); + } + + uint32_t Shard(uint32_t hash) { + // Note, hash >> 32 yields hash in gcc, not the zero we expect! + return (num_shard_bits_ > 0) ? (hash >> (32 - num_shard_bits_)) : 0; + } + + int num_shard_bits_; + mutable port::Mutex capacity_mutex_; + size_t capacity_; + bool strict_capacity_limit_; + std::atomic last_id_; +}; + +extern int GetDefaultCacheShardBits(size_t capacity); + +} // namespace rocksdb -- cgit v1.2.3