1 files changed, 166 insertions, 0 deletions
diff --git a/src/rocksdb/cache/sharded_cache.cc b/src/rocksdb/cache/sharded_cache.cc
new file mode 100644
index 00000000..a48a3218
--- /dev/null
+++ b/src/rocksdb/cache/sharded_cache.cc
@@ -0,0 +1,166 @@
+//  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.
+
+#ifndef __STDC_FORMAT_MACROS
+#define __STDC_FORMAT_MACROS
+#endif
+
+#include "cache/sharded_cache.h"
+
+#include <string>
+
+#include "util/mutexlock.h"
+
+namespace rocksdb {
+
+ShardedCache::ShardedCache(size_t capacity, int num_shard_bits,
+                           bool strict_capacity_limit,
+                           std::shared_ptr<MemoryAllocator> allocator)
+    : Cache(std::move(allocator)),
+      num_shard_bits_(num_shard_bits),
+      capacity_(capacity),
+      strict_capacity_limit_(strict_capacity_limit),
+      last_id_(1) {}
+
+void ShardedCache::SetCapacity(size_t capacity) {
+  int num_shards = 1 << num_shard_bits_;
+  const size_t per_shard = (capacity + (num_shards - 1)) / num_shards;
+  MutexLock l(&capacity_mutex_);
+  for (int s = 0; s < num_shards; s++) {
+    GetShard(s)->SetCapacity(per_shard);
+  }
+  capacity_ = capacity;
+}
+
+void ShardedCache::SetStrictCapacityLimit(bool strict_capacity_limit) {
+  int num_shards = 1 << num_shard_bits_;
+  MutexLock l(&capacity_mutex_);
+  for (int s = 0; s < num_shards; s++) {
+    GetShard(s)->SetStrictCapacityLimit(strict_capacity_limit);
+  }
+  strict_capacity_limit_ = strict_capacity_limit;
+}
+
+Status ShardedCache::Insert(const Slice& key, void* value, size_t charge,
+                            void (*deleter)(const Slice& key, void* value),
+                            Handle** handle, Priority priority) {
+  uint32_t hash = HashSlice(key);
+  return GetShard(Shard(hash))
+      ->Insert(key, hash, value, charge, deleter, handle, priority);
+}
+
+Cache::Handle* ShardedCache::Lookup(const Slice& key, Statistics* /*stats*/) {
+  uint32_t hash = HashSlice(key);
+  return GetShard(Shard(hash))->Lookup(key, hash);
+}
+
+bool ShardedCache::Ref(Handle* handle) {
+  uint32_t hash = GetHash(handle);
+  return GetShard(Shard(hash))->Ref(handle);
+}
+
+bool ShardedCache::Release(Handle* handle, bool force_erase) {
+  uint32_t hash = GetHash(handle);
+  return GetShard(Shard(hash))->Release(handle, force_erase);
+}
+
+void ShardedCache::Erase(const Slice& key) {
+  uint32_t hash = HashSlice(key);
+  GetShard(Shard(hash))->Erase(key, hash);
+}
+
+uint64_t ShardedCache::NewId() {
+  return last_id_.fetch_add(1, std::memory_order_relaxed);
+}
+
+size_t ShardedCache::GetCapacity() const {
+  MutexLock l(&capacity_mutex_);
+  return capacity_;
+}
+
+bool ShardedCache::HasStrictCapacityLimit() const {
+  MutexLock l(&capacity_mutex_);
+  return strict_capacity_limit_;
+}
+
+size_t ShardedCache::GetUsage() const {
+  // We will not lock the cache when getting the usage from shards.
+  int num_shards = 1 << num_shard_bits_;
+  size_t usage = 0;
+  for (int s = 0; s < num_shards; s++) {
+    usage += GetShard(s)->GetUsage();
+  }
+  return usage;
+}
+
+size_t ShardedCache::GetUsage(Handle* handle) const {
+  return GetCharge(handle);
+}
+
+size_t ShardedCache::GetPinnedUsage() const {
+  // We will not lock the cache when getting the usage from shards.
+  int num_shards = 1 << num_shard_bits_;
+  size_t usage = 0;
+  for (int s = 0; s < num_shards; s++) {
+    usage += GetShard(s)->GetPinnedUsage();
+  }
+  return usage;
+}
+
+void ShardedCache::ApplyToAllCacheEntries(void (*callback)(void*, size_t),
+                                          bool thread_safe) {
+  int num_shards = 1 << num_shard_bits_;
+  for (int s = 0; s < num_shards; s++) {
+    GetShard(s)->ApplyToAllCacheEntries(callback, thread_safe);
+  }
+}
+
+void ShardedCache::EraseUnRefEntries() {
+  int num_shards = 1 << num_shard_bits_;
+  for (int s = 0; s < num_shards; s++) {
+    GetShard(s)->EraseUnRefEntries();
+  }
+}
+
+std::string ShardedCache::GetPrintableOptions() const {
+  std::string ret;
+  ret.reserve(20000);
+  const int kBufferSize = 200;
+  char buffer[kBufferSize];
+  {
+    MutexLock l(&capacity_mutex_);
+    snprintf(buffer, kBufferSize, "    capacity : %" ROCKSDB_PRIszt "\n",
+             capacity_);
+    ret.append(buffer);
+    snprintf(buffer, kBufferSize, "    num_shard_bits : %d\n", num_shard_bits_);
+    ret.append(buffer);
+    snprintf(buffer, kBufferSize, "    strict_capacity_limit : %d\n",
+             strict_capacity_limit_);
+    ret.append(buffer);
+  }
+  snprintf(buffer, kBufferSize, "    memory_allocator : %s\n",
+           memory_allocator() ? memory_allocator()->Name() : "None");
+  ret.append(buffer);
+  ret.append(GetShard(0)->GetPrintableOptions());
+  return ret;
+}
+int GetDefaultCacheShardBits(size_t capacity) {
+  int num_shard_bits = 0;
+  size_t min_shard_size = 512L * 1024L;  // Every shard is at least 512KB.
+  size_t num_shards = capacity / min_shard_size;
+  while (num_shards >>= 1) {
+    if (++num_shard_bits >= 6) {
+      // No more than 6.
+      return num_shard_bits;
+    }
+  }
+  return num_shard_bits;
+}
+
+}  // namespace rocksdb