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rocksdb/cache/secondary_cache_adapter.cc

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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).
#include "cache/secondary_cache_adapter.h"
#include <atomic>
#include "cache/tiered_secondary_cache.h"
#include "monitoring/perf_context_imp.h"
#include "test_util/sync_point.h"
#include "util/cast_util.h"
namespace ROCKSDB_NAMESPACE {
namespace {
// A distinct pointer value for marking "dummy" cache entries
struct Dummy {
char val[7] = "kDummy";
};
const Dummy kDummy{};
Cache::ObjectPtr const kDummyObj = const_cast<Dummy*>(&kDummy);
const char* kTieredCacheName = "TieredCache";
} // namespace
// When CacheWithSecondaryAdapter is constructed with the distribute_cache_res
// parameter set to true, it manages the entire memory budget across the
// primary and secondary cache. The secondary cache is assumed to be in
// memory, such as the CompressedSecondaryCache. When a placeholder entry
// is inserted by a CacheReservationManager instance to reserve memory,
// the CacheWithSecondaryAdapter ensures that the reservation is distributed
// proportionally across the primary/secondary caches.
//
// The primary block cache is initially sized to the sum of the primary cache
// budget + teh secondary cache budget, as follows -
// |--------- Primary Cache Configured Capacity -----------|
// |---Secondary Cache Budget----|----Primary Cache Budget-----|
//
// A ConcurrentCacheReservationManager member in the CacheWithSecondaryAdapter,
// pri_cache_res_,
// is used to help with tracking the distribution of memory reservations.
// Initially, it accounts for the entire secondary cache budget as a
// reservation against the primary cache. This shrinks the usable capacity of
// the primary cache to the budget that the user originally desired.
//
// |--Reservation for Sec Cache--|-Pri Cache Usable Capacity---|
//
// When a reservation placeholder is inserted into the adapter, it is inserted
// directly into the primary cache. This means the entire charge of the
// placeholder is counted against the primary cache. To compensate and count
// a portion of it against the secondary cache, the secondary cache Deflate()
// method is called to shrink it. Since the Deflate() causes the secondary
// actual usage to shrink, it is refelcted here by releasing an equal amount
// from the pri_cache_res_ reservation. The Deflate() in the secondary cache
// can be, but is not required to be, implemented using its own cache
// reservation manager.
//
// For example, if the pri/sec ratio is 70/30, and the combined capacity is
// 100MB, the intermediate and final state after inserting a reservation
// placeholder for 10MB would be as follows -
//
// |-Reservation for Sec Cache-|-Pri Cache Usable Capacity-|---R---|
// 1. After inserting the placeholder in primary
// |------- 30MB -------------|------- 60MB -------------|-10MB--|
// 2. After deflating the secondary and adjusting the reservation for
// secondary against the primary
// |------- 27MB -------------|------- 63MB -------------|-10MB--|
//
// Likewise, when the user inserted placeholder is released, the secondary
// cache Inflate() method is called to grow it, and the pri_cache_res_
// reservation is increased by an equal amount.
//
// Another way of implementing this would have been to simply split the user
// reservation into primary and seconary components. However, this would
// require allocating a structure to track the associated secondary cache
// reservation, which adds some complexity and overhead.
//
CacheWithSecondaryAdapter::CacheWithSecondaryAdapter(
std::shared_ptr<Cache> target,
std::shared_ptr<SecondaryCache> secondary_cache,
TieredAdmissionPolicy adm_policy, bool distribute_cache_res)
: CacheWrapper(std::move(target)),
secondary_cache_(std::move(secondary_cache)),
adm_policy_(adm_policy),
distribute_cache_res_(distribute_cache_res),
placeholder_usage_(0),
reserved_usage_(0),
sec_reserved_(0) {
target_->SetEvictionCallback(
[this](const Slice& key, Handle* handle, bool was_hit) {
return EvictionHandler(key, handle, was_hit);
});
if (distribute_cache_res_) {
size_t sec_capacity = 0;
pri_cache_res_ = std::make_shared<ConcurrentCacheReservationManager>(
std::make_shared<CacheReservationManagerImpl<CacheEntryRole::kMisc>>(
target_));
Status s = secondary_cache_->GetCapacity(sec_capacity);
assert(s.ok());
// Initially, the primary cache is sized to uncompressed cache budget plsu
// compressed secondary cache budget. The secondary cache budget is then
// taken away from the primary cache through cache reservations. Later,
// when a placeholder entry is inserted by the caller, its inserted
// into the primary cache and the portion that should be assigned to the
// secondary cache is freed from the reservation.
s = pri_cache_res_->UpdateCacheReservation(sec_capacity);
assert(s.ok());
sec_cache_res_ratio_ = (double)sec_capacity / target_->GetCapacity();
}
}
CacheWithSecondaryAdapter::~CacheWithSecondaryAdapter() {
// `*this` will be destroyed before `*target_`, so we have to prevent
// use after free
target_->SetEvictionCallback({});
#ifndef NDEBUG
if (distribute_cache_res_) {
size_t sec_capacity = 0;
Status s = secondary_cache_->GetCapacity(sec_capacity);
assert(s.ok());
assert(placeholder_usage_ == 0);
assert(reserved_usage_ == 0);
assert(pri_cache_res_->GetTotalMemoryUsed() == sec_capacity);
}
#endif // NDEBUG
}
bool CacheWithSecondaryAdapter::EvictionHandler(const Slice& key,
Handle* handle, bool was_hit) {
auto helper = GetCacheItemHelper(handle);
if (helper->IsSecondaryCacheCompatible() &&
adm_policy_ != TieredAdmissionPolicy::kAdmPolicyThreeQueue) {
auto obj = target_->Value(handle);
// Ignore dummy entry
if (obj != kDummyObj) {
bool force = false;
if (adm_policy_ == TieredAdmissionPolicy::kAdmPolicyAllowCacheHits) {
force = was_hit;
} else if (adm_policy_ == TieredAdmissionPolicy::kAdmPolicyAllowAll) {
force = true;
}
// Spill into secondary cache.
secondary_cache_->Insert(key, obj, helper, force).PermitUncheckedError();
}
}
// Never takes ownership of obj
return false;
}
bool CacheWithSecondaryAdapter::ProcessDummyResult(Cache::Handle** handle,
bool erase) {
if (*handle && target_->Value(*handle) == kDummyObj) {
target_->Release(*handle, erase);
*handle = nullptr;
return true;
} else {
return false;
}
}
void CacheWithSecondaryAdapter::CleanupCacheObject(
ObjectPtr obj, const CacheItemHelper* helper) {
if (helper->del_cb) {
helper->del_cb(obj, memory_allocator());
}
}
Cache::Handle* CacheWithSecondaryAdapter::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) {
assert(secondary_handle->IsReady());
ObjectPtr obj = secondary_handle->Value();
if (!obj) {
// Nothing found.
return nullptr;
}
// Found something.
switch (helper->role) {
case CacheEntryRole::kFilterBlock:
RecordTick(stats, SECONDARY_CACHE_FILTER_HITS);
break;
case CacheEntryRole::kIndexBlock:
RecordTick(stats, SECONDARY_CACHE_INDEX_HITS);
break;
case CacheEntryRole::kDataBlock:
RecordTick(stats, SECONDARY_CACHE_DATA_HITS);
break;
default:
break;
}
PERF_COUNTER_ADD(secondary_cache_hit_count, 1);
RecordTick(stats, SECONDARY_CACHE_HITS);
// Note: SecondaryCache::Size() is really charge (from the CreateCallback)
size_t charge = secondary_handle->Size();
Handle* result = nullptr;
// Insert into primary cache, possibly as a standalone+dummy entries.
if (secondary_cache_->SupportForceErase() && !found_dummy_entry) {
// Create standalone and insert dummy
// Allow standalone to be created even if cache is full, to avoid
// reading the entry from storage.
result =
CreateStandalone(key, obj, helper, charge, /*allow_uncharged*/ true);
assert(result);
PERF_COUNTER_ADD(block_cache_standalone_handle_count, 1);
// Insert dummy to record recent use
// TODO: try to avoid case where inserting this dummy could overwrite a
// regular entry
Status s = Insert(key, kDummyObj, &kNoopCacheItemHelper, /*charge=*/0,
/*handle=*/nullptr, priority);
s.PermitUncheckedError();
// Nothing to do or clean up on dummy insertion failure
} else {
// Insert regular entry into primary cache.
// Don't allow it to spill into secondary cache again if it was kept there.
Status s = Insert(
key, obj, kept_in_sec_cache ? helper->without_secondary_compat : helper,
charge, &result, priority);
if (s.ok()) {
assert(result);
PERF_COUNTER_ADD(block_cache_real_handle_count, 1);
} else {
// Create standalone result instead, even if cache is full, to avoid
// reading the entry from storage.
result =
CreateStandalone(key, obj, helper, charge, /*allow_uncharged*/ true);
assert(result);
PERF_COUNTER_ADD(block_cache_standalone_handle_count, 1);
}
}
return result;
}
Status CacheWithSecondaryAdapter::Insert(const Slice& key, ObjectPtr value,
const CacheItemHelper* helper,
size_t charge, Handle** handle,
Priority priority,
const Slice& compressed_value,
CompressionType type) {
Status s = target_->Insert(key, value, helper, charge, handle, priority);
if (s.ok() && value == nullptr && distribute_cache_res_ && handle) {
charge = target_->GetCharge(*handle);
MutexLock l(&cache_res_mutex_);
placeholder_usage_ += charge;
// Check if total placeholder reservation is more than the overall
// cache capacity. If it is, then we don't try to charge the
// secondary cache because we don't want to overcharge it (beyond
// its capacity).
// In order to make this a bit more lightweight, we also check if
// the difference between placeholder_usage_ and reserved_usage_ is
// atleast kReservationChunkSize and avoid any adjustments if not.
if ((placeholder_usage_ <= target_->GetCapacity()) &&
((placeholder_usage_ - reserved_usage_) >= kReservationChunkSize)) {
reserved_usage_ = placeholder_usage_ & ~(kReservationChunkSize - 1);
size_t new_sec_reserved =
static_cast<size_t>(reserved_usage_ * sec_cache_res_ratio_);
size_t sec_charge = new_sec_reserved - sec_reserved_;
s = secondary_cache_->Deflate(sec_charge);
assert(s.ok());
s = pri_cache_res_->UpdateCacheReservation(sec_charge,
/*increase=*/false);
assert(s.ok());
sec_reserved_ += sec_charge;
}
}
// Warm up the secondary cache with the compressed block. The secondary
// cache may choose to ignore it based on the admission policy.
if (value != nullptr && !compressed_value.empty() &&
adm_policy_ == TieredAdmissionPolicy::kAdmPolicyThreeQueue &&
helper->IsSecondaryCacheCompatible()) {
Status status = secondary_cache_->InsertSaved(key, compressed_value, type);
assert(status.ok() || status.IsNotSupported());
}
return s;
}
Cache::Handle* CacheWithSecondaryAdapter::Lookup(const Slice& key,
const CacheItemHelper* helper,
CreateContext* create_context,
Priority priority,
Statistics* stats) {
// NOTE: we could just StartAsyncLookup() and Wait(), but this should be a bit
// more efficient
Handle* result =
target_->Lookup(key, helper, create_context, priority, stats);
bool secondary_compatible = helper && helper->IsSecondaryCacheCompatible();
bool found_dummy_entry =
ProcessDummyResult(&result, /*erase=*/secondary_compatible);
if (!result && secondary_compatible) {
// Try our secondary cache
bool kept_in_sec_cache = false;
std::unique_ptr<SecondaryCacheResultHandle> secondary_handle =
secondary_cache_->Lookup(key, helper, create_context, /*wait*/ true,
found_dummy_entry, stats,
/*out*/ kept_in_sec_cache);
if (secondary_handle) {
result = Promote(std::move(secondary_handle), key, helper, priority,
stats, found_dummy_entry, kept_in_sec_cache);
}
}
return result;
}
bool CacheWithSecondaryAdapter::Release(Handle* handle,
bool erase_if_last_ref) {
if (erase_if_last_ref) {
ObjectPtr v = target_->Value(handle);
if (v == nullptr && distribute_cache_res_) {
size_t charge = target_->GetCharge(handle);
MutexLock l(&cache_res_mutex_);
placeholder_usage_ -= charge;
// Check if total placeholder reservation is more than the overall
// cache capacity. If it is, then we do nothing as reserved_usage_ must
// be already maxed out
if ((placeholder_usage_ <= target_->GetCapacity()) &&
(placeholder_usage_ < reserved_usage_)) {
// Adjust reserved_usage_ in chunks of kReservationChunkSize, so
// we don't hit this slow path too often.
reserved_usage_ = placeholder_usage_ & ~(kReservationChunkSize - 1);
size_t new_sec_reserved =
static_cast<size_t>(reserved_usage_ * sec_cache_res_ratio_);
size_t sec_charge = sec_reserved_ - new_sec_reserved;
Status s = secondary_cache_->Inflate(sec_charge);
assert(s.ok());
s = pri_cache_res_->UpdateCacheReservation(sec_charge,
/*increase=*/true);
assert(s.ok());
sec_reserved_ -= sec_charge;
}
}
}
return target_->Release(handle, erase_if_last_ref);
}
Cache::ObjectPtr CacheWithSecondaryAdapter::Value(Handle* handle) {
ObjectPtr v = target_->Value(handle);
// TODO with stacked secondaries: might fail in EvictionHandler
assert(v != kDummyObj);
return v;
}
void CacheWithSecondaryAdapter::StartAsyncLookupOnMySecondary(
AsyncLookupHandle& async_handle) {
assert(!async_handle.IsPending());
assert(async_handle.result_handle == nullptr);
std::unique_ptr<SecondaryCacheResultHandle> secondary_handle =
secondary_cache_->Lookup(
async_handle.key, async_handle.helper, async_handle.create_context,
/*wait*/ false, async_handle.found_dummy_entry, async_handle.stats,
/*out*/ async_handle.kept_in_sec_cache);
if (secondary_handle) {
// TODO with stacked secondaries: Check & process if already ready?
async_handle.pending_handle = secondary_handle.release();
async_handle.pending_cache = secondary_cache_.get();
}
}
void CacheWithSecondaryAdapter::StartAsyncLookup(
AsyncLookupHandle& async_handle) {
target_->StartAsyncLookup(async_handle);
if (!async_handle.IsPending()) {
bool secondary_compatible =
async_handle.helper &&
async_handle.helper->IsSecondaryCacheCompatible();
async_handle.found_dummy_entry |= ProcessDummyResult(
&async_handle.result_handle, /*erase=*/secondary_compatible);
if (async_handle.Result() == nullptr && secondary_compatible) {
// Not found and not pending on another secondary cache
StartAsyncLookupOnMySecondary(async_handle);
}
}
}
void CacheWithSecondaryAdapter::WaitAll(AsyncLookupHandle* async_handles,
size_t count) {
if (count == 0) {
// Nothing to do
return;
}
// Requests that are pending on *my* secondary cache, at the start of this
// function
std::vector<AsyncLookupHandle*> my_pending;
// Requests that are pending on an "inner" secondary cache (managed somewhere
// under target_), as of the start of this function
std::vector<AsyncLookupHandle*> inner_pending;
// Initial accounting of pending handles, excluding those already handled
// by "outer" secondary caches. (See cur->pending_cache = nullptr.)
for (size_t i = 0; i < count; ++i) {
AsyncLookupHandle* cur = async_handles + i;
if (cur->pending_cache) {
assert(cur->IsPending());
assert(cur->helper);
assert(cur->helper->IsSecondaryCacheCompatible());
if (cur->pending_cache == secondary_cache_.get()) {
my_pending.push_back(cur);
// Mark as "to be handled by this caller"
cur->pending_cache = nullptr;
} else {
// Remember as potentially needing a lookup in my secondary
inner_pending.push_back(cur);
}
}
}
// Wait on inner-most cache lookups first
// TODO with stacked secondaries: because we are not using proper
// async/await constructs here yet, there is a false synchronization point
// here where all the results at one level are needed before initiating
// any lookups at the next level. Probably not a big deal, but worth noting.
if (!inner_pending.empty()) {
target_->WaitAll(async_handles, count);
}
// For those that failed to find something, convert to lookup in my
// secondary cache.
for (AsyncLookupHandle* cur : inner_pending) {
if (cur->Result() == nullptr) {
// Not found, try my secondary
StartAsyncLookupOnMySecondary(*cur);
if (cur->IsPending()) {
assert(cur->pending_cache == secondary_cache_.get());
my_pending.push_back(cur);
// Mark as "to be handled by this caller"
cur->pending_cache = nullptr;
}
}
}
// Wait on all lookups on my secondary cache
{
std::vector<SecondaryCacheResultHandle*> my_secondary_handles;
for (AsyncLookupHandle* cur : my_pending) {
my_secondary_handles.push_back(cur->pending_handle);
}
secondary_cache_->WaitAll(std::move(my_secondary_handles));
}
// Process results
for (AsyncLookupHandle* cur : my_pending) {
std::unique_ptr<SecondaryCacheResultHandle> secondary_handle(
cur->pending_handle);
cur->pending_handle = nullptr;
cur->result_handle = Promote(
std::move(secondary_handle), cur->key, cur->helper, cur->priority,
cur->stats, cur->found_dummy_entry, cur->kept_in_sec_cache);
assert(cur->pending_cache == nullptr);
}
}
std::string CacheWithSecondaryAdapter::GetPrintableOptions() const {
std::string str = target_->GetPrintableOptions();
str.append(" secondary_cache:\n");
str.append(secondary_cache_->GetPrintableOptions());
return str;
}
const char* CacheWithSecondaryAdapter::Name() const {
if (distribute_cache_res_) {
return kTieredCacheName;
} else {
// To the user, at least for now, configure the underlying cache with
// a secondary cache. So we pretend to be that cache
return target_->Name();
}
}
// Update the total cache capacity. If we're distributing cache reservations
// to both primary and secondary, then update the pri_cache_res_reservation
// as well. At the moment, we don't have a good way of handling the case
// where the new capacity < total cache reservations.
void CacheWithSecondaryAdapter::SetCapacity(size_t capacity) {
size_t sec_capacity = static_cast<size_t>(
capacity * (distribute_cache_res_ ? sec_cache_res_ratio_ : 0.0));
size_t old_sec_capacity = 0;
if (distribute_cache_res_) {
MutexLock m(&cache_res_mutex_);
Status s = secondary_cache_->GetCapacity(old_sec_capacity);
if (!s.ok()) {
return;
}
if (old_sec_capacity > sec_capacity) {
// We're shrinking the cache. We do things in the following order to
// avoid a temporary spike in usage over the configured capacity -
// 1. Lower the secondary cache capacity
// 2. Credit an equal amount (by decreasing pri_cache_res_) to the
// primary cache
// 3. Decrease the primary cache capacity to the total budget
s = secondary_cache_->SetCapacity(sec_capacity);
if (s.ok()) {
if (placeholder_usage_ > capacity) {
// Adjust reserved_usage_ down
reserved_usage_ = capacity & ~(kReservationChunkSize - 1);
}
size_t new_sec_reserved =
static_cast<size_t>(reserved_usage_ * sec_cache_res_ratio_);
s = pri_cache_res_->UpdateCacheReservation(
(old_sec_capacity - sec_capacity) -
(sec_reserved_ - new_sec_reserved),
/*increase=*/false);
sec_reserved_ = new_sec_reserved;
assert(s.ok());
target_->SetCapacity(capacity);
}
} else {
// We're expanding the cache. Do it in the following order to avoid
// unnecessary evictions -
// 1. Increase the primary cache capacity to total budget
// 2. Reserve additional memory in primary on behalf of secondary (by
// increasing pri_cache_res_ reservation)
// 3. Increase secondary cache capacity
target_->SetCapacity(capacity);
s = pri_cache_res_->UpdateCacheReservation(
sec_capacity - old_sec_capacity,
/*increase=*/true);
assert(s.ok());
s = secondary_cache_->SetCapacity(sec_capacity);
assert(s.ok());
}
} else {
// No cache reservation distribution. Just set the primary cache capacity.
target_->SetCapacity(capacity);
}
}
Status CacheWithSecondaryAdapter::GetSecondaryCacheCapacity(
size_t& size) const {
return secondary_cache_->GetCapacity(size);
}
Status CacheWithSecondaryAdapter::GetSecondaryCachePinnedUsage(
size_t& size) const {
Status s;
if (distribute_cache_res_) {
MutexLock m(&cache_res_mutex_);
size_t capacity = 0;
s = secondary_cache_->GetCapacity(capacity);
if (s.ok()) {
size = capacity - pri_cache_res_->GetTotalMemoryUsed();
} else {
size = 0;
}
} else {
size = 0;
}
return s;
}
// Update the secondary/primary allocation ratio (remember, the primary
// capacity is the total memory budget when distribute_cache_res_ is true).
// When the ratio changes, we may accumulate some error in the calculations
// for secondary cache inflate/deflate and pri_cache_res_ reservations.
// This is due to the rounding of the reservation amount.
//
// We rely on the current pri_cache_res_ total memory used to estimate the
// new secondary cache reservation after the ratio change. For this reason,
// once the ratio is lowered to 0.0 (effectively disabling the secondary
// cache and pri_cache_res_ total mem used going down to 0), we cannot
// increase the ratio and re-enable it, We might remove this limitation
// in the future.
Status CacheWithSecondaryAdapter::UpdateCacheReservationRatio(
double compressed_secondary_ratio) {
if (!distribute_cache_res_) {
return Status::NotSupported();
}
MutexLock m(&cache_res_mutex_);
size_t pri_capacity = target_->GetCapacity();
size_t sec_capacity =
static_cast<size_t>(pri_capacity * compressed_secondary_ratio);
size_t old_sec_capacity;
Status s = secondary_cache_->GetCapacity(old_sec_capacity);
if (!s.ok()) {
return s;
}
// Calculate the new secondary cache reservation
// reserved_usage_ will never be > the cache capacity, so we don't
// have to worry about adjusting it here.
sec_cache_res_ratio_ = compressed_secondary_ratio;
size_t new_sec_reserved =
static_cast<size_t>(reserved_usage_ * sec_cache_res_ratio_);
if (sec_capacity > old_sec_capacity) {
// We're increasing the ratio, thus ending up with a larger secondary
// cache and a smaller usable primary cache capacity. Similar to
// SetCapacity(), we try to avoid a temporary increase in total usage
// beyond the configured capacity -
// 1. A higher secondary cache ratio means it gets a higher share of
// cache reservations. So first account for that by deflating the
// secondary cache
// 2. Increase pri_cache_res_ reservation to reflect the new secondary
// cache utilization (increase in capacity - increase in share of cache
// reservation)
// 3. Increase secondary cache capacity
s = secondary_cache_->Deflate(new_sec_reserved - sec_reserved_);
assert(s.ok());
s = pri_cache_res_->UpdateCacheReservation(
(sec_capacity - old_sec_capacity) - (new_sec_reserved - sec_reserved_),
/*increase=*/true);
assert(s.ok());
sec_reserved_ = new_sec_reserved;
s = secondary_cache_->SetCapacity(sec_capacity);
assert(s.ok());
} else {
// We're shrinking the ratio. Try to avoid unnecessary evictions -
// 1. Lower the secondary cache capacity
// 2. Decrease pri_cache_res_ reservation to relect lower secondary
// cache utilization (decrease in capacity - decrease in share of cache
// reservations)
// 3. Inflate the secondary cache to give it back the reduction in its
// share of cache reservations
s = secondary_cache_->SetCapacity(sec_capacity);
if (s.ok()) {
s = pri_cache_res_->UpdateCacheReservation(
(old_sec_capacity - sec_capacity) -
(sec_reserved_ - new_sec_reserved),
/*increase=*/false);
assert(s.ok());
s = secondary_cache_->Inflate(sec_reserved_ - new_sec_reserved);
assert(s.ok());
sec_reserved_ = new_sec_reserved;
}
}
return s;
}
Status CacheWithSecondaryAdapter::UpdateAdmissionPolicy(
TieredAdmissionPolicy adm_policy) {
adm_policy_ = adm_policy;
return Status::OK();
}
std::shared_ptr<Cache> NewTieredCache(const TieredCacheOptions& _opts) {
if (!_opts.cache_opts) {
return nullptr;
}
TieredCacheOptions opts = _opts;
{
bool valid_adm_policy = true;
switch (_opts.adm_policy) {
case TieredAdmissionPolicy::kAdmPolicyAuto:
// Select an appropriate default policy
if (opts.adm_policy == TieredAdmissionPolicy::kAdmPolicyAuto) {
if (opts.nvm_sec_cache) {
opts.adm_policy = TieredAdmissionPolicy::kAdmPolicyThreeQueue;
} else {
opts.adm_policy = TieredAdmissionPolicy::kAdmPolicyPlaceholder;
}
}
break;
case TieredAdmissionPolicy::kAdmPolicyPlaceholder:
case TieredAdmissionPolicy::kAdmPolicyAllowCacheHits:
case TieredAdmissionPolicy::kAdmPolicyAllowAll:
if (opts.nvm_sec_cache) {
valid_adm_policy = false;
}
break;
case TieredAdmissionPolicy::kAdmPolicyThreeQueue:
if (!opts.nvm_sec_cache) {
valid_adm_policy = false;
}
break;
default:
valid_adm_policy = false;
}
if (!valid_adm_policy) {
return nullptr;
}
}
std::shared_ptr<Cache> cache;
if (opts.cache_type == PrimaryCacheType::kCacheTypeLRU) {
LRUCacheOptions cache_opts =
*(static_cast_with_check<LRUCacheOptions, ShardedCacheOptions>(
opts.cache_opts));
cache_opts.capacity = opts.total_capacity;
cache_opts.secondary_cache = nullptr;
cache = cache_opts.MakeSharedCache();
} else if (opts.cache_type == PrimaryCacheType::kCacheTypeHCC) {
HyperClockCacheOptions cache_opts =
*(static_cast_with_check<HyperClockCacheOptions, ShardedCacheOptions>(
opts.cache_opts));
cache_opts.capacity = opts.total_capacity;
cache_opts.secondary_cache = nullptr;
cache = cache_opts.MakeSharedCache();
} else {
return nullptr;
}
std::shared_ptr<SecondaryCache> sec_cache;
opts.comp_cache_opts.capacity = static_cast<size_t>(
opts.total_capacity * opts.compressed_secondary_ratio);
sec_cache = NewCompressedSecondaryCache(opts.comp_cache_opts);
if (opts.nvm_sec_cache) {
if (opts.adm_policy == TieredAdmissionPolicy::kAdmPolicyThreeQueue) {
sec_cache = std::make_shared<TieredSecondaryCache>(
sec_cache, opts.nvm_sec_cache,
TieredAdmissionPolicy::kAdmPolicyThreeQueue);
} else {
return nullptr;
}
}
return std::make_shared<CacheWithSecondaryAdapter>(
cache, sec_cache, opts.adm_policy, /*distribute_cache_res=*/true);
}
Status UpdateTieredCache(const std::shared_ptr<Cache>& cache,
int64_t total_capacity,
double compressed_secondary_ratio,
TieredAdmissionPolicy adm_policy) {
if (!cache || strcmp(cache->Name(), kTieredCacheName)) {
return Status::InvalidArgument();
}
CacheWithSecondaryAdapter* tiered_cache =
static_cast<CacheWithSecondaryAdapter*>(cache.get());
Status s;
if (total_capacity > 0) {
tiered_cache->SetCapacity(total_capacity);
}
if (compressed_secondary_ratio >= 0.0 && compressed_secondary_ratio <= 1.0) {
s = tiered_cache->UpdateCacheReservationRatio(compressed_secondary_ratio);
}
if (adm_policy < TieredAdmissionPolicy::kAdmPolicyMax) {
s = tiered_cache->UpdateAdmissionPolicy(adm_policy);
}
return s;
}
} // namespace ROCKSDB_NAMESPACE
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