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// Copyright (c) Meta Platforms, Inc. and affiliates.
// 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 "cache/cache_reservation_manager.h"
#include "rocksdb/secondary_cache.h"
namespace ROCKSDB_NAMESPACE {
class CacheWithSecondaryAdapter : public CacheWrapper {
public:
explicit CacheWithSecondaryAdapter(
std::shared_ptr<Cache> target,
std::shared_ptr<SecondaryCache> secondary_cache,
TieredAdmissionPolicy adm_policy = TieredAdmissionPolicy::kAdmPolicyAuto,
bool distribute_cache_res = false);
~CacheWithSecondaryAdapter() override;
Status Insert(
const Slice& key, ObjectPtr value, const CacheItemHelper* helper,
size_t charge, Handle** handle = nullptr,
Priority priority = Priority::LOW,
const Slice& compressed_value = Slice(),
CompressionType type = CompressionType::kNoCompression) override;
Handle* Lookup(const Slice& key, const CacheItemHelper* helper,
CreateContext* create_context,
Priority priority = Priority::LOW,
Statistics* stats = nullptr) override;
using Cache::Release;
bool Release(Handle* handle, bool erase_if_last_ref = false) override;
ObjectPtr Value(Handle* handle) override;
void StartAsyncLookup(AsyncLookupHandle& async_handle) override;
void WaitAll(AsyncLookupHandle* async_handles, size_t count) override;
std::string GetPrintableOptions() const override;
const char* Name() const override;
void SetCapacity(size_t capacity) override;
Status GetSecondaryCacheCapacity(size_t& size) const override;
Status GetSecondaryCachePinnedUsage(size_t& size) const override;
Status UpdateCacheReservationRatio(double ratio);
Status UpdateAdmissionPolicy(TieredAdmissionPolicy adm_policy);
Cache* TEST_GetCache() { return target_.get(); }
SecondaryCache* TEST_GetSecondaryCache() { return secondary_cache_.get(); }
private:
static constexpr size_t kReservationChunkSize = 1 << 20;
bool EvictionHandler(const Slice& key, Handle* handle, bool was_hit);
void StartAsyncLookupOnMySecondary(AsyncLookupHandle& async_handle);
Handle* Promote(
std::unique_ptr<SecondaryCacheResultHandle>&& secondary_handle,
const Slice& key, const CacheItemHelper* helper, Priority priority,
Statistics* stats, bool found_dummy_entry, bool kept_in_sec_cache);
bool ProcessDummyResult(Cache::Handle** handle, bool erase);
void CleanupCacheObject(ObjectPtr obj, const CacheItemHelper* helper);
std::shared_ptr<SecondaryCache> secondary_cache_;
TieredAdmissionPolicy adm_policy_;
// Whether to proportionally distribute cache memory reservations, i.e
// placeholder entries with null value and a non-zero charge, across
// the primary and secondary caches.
bool distribute_cache_res_;
// A cache reservation manager to keep track of secondary cache memory
// usage by reserving equivalent capacity against the primary cache
std::shared_ptr<ConcurrentCacheReservationManager> pri_cache_res_;
// Fraction of a cache memory reservation to be assigned to the secondary
// cache
double sec_cache_res_ratio_;
// Mutex for use when managing cache memory reservations. Should not be used
// for other purposes, as it may risk causing deadlocks.
mutable port::Mutex cache_res_mutex_;
// Total memory reserved by placeholder entriesin the cache
size_t placeholder_usage_;
// Total placeholoder memory charged to both the primary and secondary
// caches. Will be <= placeholder_usage_.
size_t reserved_usage_;
// Amount of memory reserved in the secondary cache. This should be
// reserved_usage_ * sec_cache_res_ratio_ in steady state.
size_t sec_reserved_;
};
} // namespace ROCKSDB_NAMESPACE
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