mirror of https://github.com/facebook/rocksdb.git
Add new API CacheReservationManager::GetTotalMemoryUsage() (#9071)
Summary:
Note: This PR is the 2nd PR of a bigger PR stack (https://github.com/facebook/rocksdb/pull/9073).
Context:
`CacheReservationManager::UpdateCacheReservation(std::size_t new_memory_used)` accepts an accumulated total memory used (e.g, used 10MB so far) instead of usage change (e.g, increase by 5 MB, decrease by 5 MB). It has benefits including consolidating API for increase and decrease as described in https://github.com/facebook/rocksdb/pull/8506.
However, not every `CacheReservationManager` user keeps track of this accumulated total memory usage. For example, Bloom/Ribbon Filter construction (e.g, [here](822d729fcd/table/block_based/filter_policy.cc (L587)) in https://github.com/facebook/rocksdb/pull/9073) does not while WriteBufferManager and compression dictionary buffering do.
Considering future users might or might not keep track of this counter and implementing this counter within `CacheReservationManager` is easy due to the passed-in `std::size_t new_memory_used` in calling `CacheReservationManager::UpdateCacheReservation(std::size_t new_memory_used)`, it is proposed to add a new API `CacheReservationManager::GetTotalMemoryUsage()`.
As noted in the API comments, since `CacheReservationManager` is NOT thread-safe, external synchronization is
needed in calling `UpdateCacheReservation()` if you want `GetTotalMemoryUsed()` returns the indeed latest memory used.
- Added and updated private counter `memory_used_` every time `CacheReservationManager::UpdateCacheReservation(std::size_t new_memory_used)` is called regardless if the call returns non-okay status
- Added `CacheReservationManager::GetTotalMemoryUsage()` to return `memory_used_`
Pull Request resolved: https://github.com/facebook/rocksdb/pull/9071
Test Plan:
- Passing new tests
- Passing existing tests
Reviewed By: ajkr
Differential Revision: D31887813
Pulled By: hx235
fbshipit-source-id: 9a09f0c8683822673260362894c878b61ee60ceb
This commit is contained in:
Hui Xiao
Facebook GitHub Bot
parent
efaef9b40a
commit
ffd6085e1f
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@ -23,7 +23,9 @@
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namespace ROCKSDB_NAMESPACE {
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CacheReservationManager::CacheReservationManager(std::shared_ptr<Cache> cache,
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bool delayed_decrease)
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: delayed_decrease_(delayed_decrease), cache_allocated_size_(0) {
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: delayed_decrease_(delayed_decrease),
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cache_allocated_size_(0),
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memory_used_(0) {
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assert(cache != nullptr);
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cache_ = cache;
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std::memset(cache_key_, 0, kCacheKeyPrefixSize + kMaxVarint64Length);
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@ -39,6 +41,7 @@ CacheReservationManager::~CacheReservationManager() {
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template <CacheEntryRole R>
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Status CacheReservationManager::UpdateCacheReservation(
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std::size_t new_mem_used) {
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memory_used_ = new_mem_used;
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std::size_t cur_cache_allocated_size =
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cache_allocated_size_.load(std::memory_order_relaxed);
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if (new_mem_used == cur_cache_allocated_size) {
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@ -118,6 +121,10 @@ std::size_t CacheReservationManager::GetTotalReservedCacheSize() {
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return cache_allocated_size_.load(std::memory_order_relaxed);
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}
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std::size_t CacheReservationManager::GetTotalMemoryUsed() {
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return memory_used_;
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}
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Slice CacheReservationManager::GetNextCacheKey() {
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// Calling this function will have the side-effect of changing the
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// underlying cache_key_ that is shared among other keys generated from this
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@ -128,4 +135,4 @@ Slice CacheReservationManager::GetNextCacheKey() {
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EncodeVarint64(cache_key_ + kCacheKeyPrefixSize, next_cache_key_id_++);
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return Slice(cache_key_, static_cast<std::size_t>(end - cache_key_));
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}
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} // namespace ROCKSDB_NAMESPACE
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} // namespace ROCKSDB_NAMESPACE
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@ -26,7 +26,9 @@ namespace ROCKSDB_NAMESPACE {
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// CacheReservationManager is for reserving cache space for the memory used
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// through inserting/releasing dummy entries in the cache.
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// This class is not thread-safe.
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//
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// This class is NOT thread-safe, except that GetTotalReservedCacheSize()
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// can be called without external synchronization.
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class CacheReservationManager {
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public:
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// Construct a CacheReservationManager
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@ -53,8 +55,8 @@ class CacheReservationManager {
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template <CacheEntryRole R>
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// Insert and release dummy entries in the cache to
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// match the size of total dummy entries with the smallest multiple of
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// kSizeDummyEntry that is greater than or equal to new_mem_used
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// match the size of total dummy entries with the least multiple of
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// kSizeDummyEntry greater than or equal to new_mem_used
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//
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// Insert dummy entries if new_memory_used > cache_allocated_size_;
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//
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@ -68,13 +70,34 @@ class CacheReservationManager {
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// is set true.
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//
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// @param new_memory_used The number of bytes used by new memory
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// The most recent new_memoy_used passed in will be returned
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// in GetTotalMemoryUsed() even when the call return non-ok status.
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//
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// Since the class is NOT thread-safe, external synchronization on the
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// order of calling UpdateCacheReservation() is needed if you want
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// GetTotalMemoryUsed() indeed returns the latest memory used.
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//
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// @return On inserting dummy entries, it returns Status::OK() if all dummy
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// entry insertions succeed. Otherwise, it returns the first non-ok status;
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// On releasing dummy entries, it always returns Status::OK().
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// On keeping dummy entries the same, it always returns Status::OK().
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// entry insertions succeed.
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// Otherwise, it returns the first non-ok status;
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// On releasing dummy entries, it always returns Status::OK().
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// On keeping dummy entries the same, it always returns Status::OK().
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Status UpdateCacheReservation(std::size_t new_memory_used);
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// Return the size of the cache (which is a multiple of kSizeDummyEntry)
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// successfully reserved by calling UpdateCacheReservation().
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//
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// When UpdateCacheReservation() returns non-ok status,
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// calling GetTotalReservedCacheSize() after that might return a slightly
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// smaller number than the actual reserved cache size due to
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// the returned number will always be a multiple of kSizeDummyEntry
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// and cache full might happen in the middle of inserting a dummy entry.
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std::size_t GetTotalReservedCacheSize();
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// Return the latest total memory used indicated by the most recent call of
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// UpdateCacheReservation(std::size_t new_memory_used);
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std::size_t GetTotalMemoryUsed();
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static constexpr std::size_t GetDummyEntrySize() { return kSizeDummyEntry; }
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private:
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@ -92,6 +115,7 @@ class CacheReservationManager {
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std::shared_ptr<Cache> cache_;
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bool delayed_decrease_;
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std::atomic<std::size_t> cache_allocated_size_;
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std::size_t memory_used_;
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std::vector<Cache::Handle *> dummy_handles_;
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std::uint64_t next_cache_key_id_ = 0;
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// The non-prefix part will be updated according to the ID to use.
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@ -81,6 +81,7 @@ TEST_F(CacheReservationManagerTest, KeepCacheReservationTheSame) {
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ASSERT_EQ(s, Status::OK());
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ASSERT_EQ(test_cache_rev_mng->GetTotalReservedCacheSize(),
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1 * kSizeDummyEntry);
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ASSERT_EQ(test_cache_rev_mng->GetTotalMemoryUsed(), new_mem_used);
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std::size_t initial_pinned_usage = cache->GetPinnedUsage();
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ASSERT_GE(initial_pinned_usage, 1 * kSizeDummyEntry);
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ASSERT_LT(initial_pinned_usage,
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@ -96,6 +97,9 @@ TEST_F(CacheReservationManagerTest, KeepCacheReservationTheSame) {
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1 * kSizeDummyEntry)
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<< "Failed to bookkeep correctly when new_mem_used equals to current "
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"cache reservation";
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EXPECT_EQ(test_cache_rev_mng->GetTotalMemoryUsed(), new_mem_used)
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<< "Failed to bookkeep the used memory correctly when new_mem_used "
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"equals to current cache reservation";
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EXPECT_EQ(cache->GetPinnedUsage(), initial_pinned_usage)
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<< "Failed to keep underlying dummy entries the same when new_mem_used "
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"equals to current cache reservation";
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@ -113,6 +117,8 @@ TEST_F(CacheReservationManagerTest,
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EXPECT_EQ(test_cache_rev_mng->GetTotalReservedCacheSize(),
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2 * kSizeDummyEntry)
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<< "Failed to bookkeep cache reservation increase correctly";
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EXPECT_EQ(test_cache_rev_mng->GetTotalMemoryUsed(), new_mem_used)
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<< "Failed to bookkeep the used memory correctly";
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EXPECT_GE(cache->GetPinnedUsage(), 2 * kSizeDummyEntry)
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<< "Failed to increase underlying dummy entries in cache correctly";
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EXPECT_LT(cache->GetPinnedUsage(),
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@ -132,6 +138,8 @@ TEST_F(CacheReservationManagerTest,
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EXPECT_EQ(test_cache_rev_mng->GetTotalReservedCacheSize(),
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3 * kSizeDummyEntry)
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<< "Failed to bookkeep cache reservation increase correctly";
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EXPECT_EQ(test_cache_rev_mng->GetTotalMemoryUsed(), new_mem_used)
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<< "Failed to bookkeep the used memory correctly";
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EXPECT_GE(cache->GetPinnedUsage(), 3 * kSizeDummyEntry)
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<< "Failed to increase underlying dummy entries in cache correctly";
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EXPECT_LT(cache->GetPinnedUsage(),
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@ -173,6 +181,8 @@ TEST(CacheReservationManagerIncreaseReservcationOnFullCacheTest,
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<< "Failed to bookkeep correctly (i.e, bookkeep only successful dummy "
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"entry insertions) when encountering cache resevation failure due to "
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"full cache";
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EXPECT_EQ(test_cache_rev_mng->GetTotalMemoryUsed(), new_mem_used)
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<< "Failed to bookkeep the used memory correctly";
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EXPECT_GE(cache->GetPinnedUsage(), 1 * kSizeDummyEntry)
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<< "Failed to insert underlying dummy entries correctly when "
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"encountering cache resevation failure due to full cache";
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@ -191,6 +201,8 @@ TEST(CacheReservationManagerIncreaseReservcationOnFullCacheTest,
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2 * kSizeDummyEntry)
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<< "Failed to bookkeep cache reservation decrease correctly after "
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"encountering cache reservation due to full cache";
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EXPECT_EQ(test_cache_rev_mng->GetTotalMemoryUsed(), new_mem_used)
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<< "Failed to bookkeep the used memory correctly";
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EXPECT_GE(cache->GetPinnedUsage(), 2 * kSizeDummyEntry)
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<< "Failed to release underlying dummy entries correctly on cache "
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"reservation decrease after encountering cache resevation failure due "
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@ -218,6 +230,8 @@ TEST(CacheReservationManagerIncreaseReservcationOnFullCacheTest,
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<< "Failed to bookkeep correctly (i.e, bookkeep only successful dummy "
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"entry insertions) when encountering cache resevation failure due to "
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"full cache";
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EXPECT_EQ(test_cache_rev_mng->GetTotalMemoryUsed(), new_mem_used)
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<< "Failed to bookkeep the used memory correctly";
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EXPECT_GE(cache->GetPinnedUsage(), 1 * kSizeDummyEntry)
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<< "Failed to insert underlying dummy entries correctly when "
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"encountering cache resevation failure due to full cache";
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@ -239,6 +253,8 @@ TEST(CacheReservationManagerIncreaseReservcationOnFullCacheTest,
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5 * kSizeDummyEntry)
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<< "Failed to bookkeep cache reservation increase correctly after "
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"increasing cache capacity and mitigating cache full error";
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EXPECT_EQ(test_cache_rev_mng->GetTotalMemoryUsed(), new_mem_used)
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<< "Failed to bookkeep the used memory correctly";
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EXPECT_GE(cache->GetPinnedUsage(), 5 * kSizeDummyEntry)
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<< "Failed to insert underlying dummy entries correctly after increasing "
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"cache capacity and mitigating cache full error";
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@ -258,6 +274,7 @@ TEST_F(CacheReservationManagerTest,
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ASSERT_EQ(s, Status::OK());
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ASSERT_EQ(test_cache_rev_mng->GetTotalReservedCacheSize(),
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2 * kSizeDummyEntry);
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ASSERT_EQ(test_cache_rev_mng->GetTotalMemoryUsed(), new_mem_used);
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ASSERT_GE(cache->GetPinnedUsage(), 2 * kSizeDummyEntry);
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ASSERT_LT(cache->GetPinnedUsage(),
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2 * kSizeDummyEntry + kMetaDataChargeOverhead);
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@ -271,6 +288,8 @@ TEST_F(CacheReservationManagerTest,
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EXPECT_EQ(test_cache_rev_mng->GetTotalReservedCacheSize(),
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1 * kSizeDummyEntry)
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<< "Failed to bookkeep cache reservation decrease correctly";
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EXPECT_EQ(test_cache_rev_mng->GetTotalMemoryUsed(), new_mem_used)
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<< "Failed to bookkeep the used memory correctly";
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EXPECT_GE(cache->GetPinnedUsage(), 1 * kSizeDummyEntry)
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<< "Failed to decrease underlying dummy entries in cache correctly";
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EXPECT_LT(cache->GetPinnedUsage(),
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@ -288,6 +307,7 @@ TEST_F(CacheReservationManagerTest,
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ASSERT_EQ(s, Status::OK());
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ASSERT_EQ(test_cache_rev_mng->GetTotalReservedCacheSize(),
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2 * kSizeDummyEntry);
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ASSERT_EQ(test_cache_rev_mng->GetTotalMemoryUsed(), new_mem_used);
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ASSERT_GE(cache->GetPinnedUsage(), 2 * kSizeDummyEntry);
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ASSERT_LT(cache->GetPinnedUsage(),
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2 * kSizeDummyEntry + kMetaDataChargeOverhead);
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@ -301,6 +321,8 @@ TEST_F(CacheReservationManagerTest,
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EXPECT_EQ(test_cache_rev_mng->GetTotalReservedCacheSize(),
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1 * kSizeDummyEntry)
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<< "Failed to bookkeep cache reservation decrease correctly";
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EXPECT_EQ(test_cache_rev_mng->GetTotalMemoryUsed(), new_mem_used)
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<< "Failed to bookkeep the used memory correctly";
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EXPECT_GE(cache->GetPinnedUsage(), 1 * kSizeDummyEntry)
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<< "Failed to decrease underlying dummy entries in cache correctly";
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EXPECT_LT(cache->GetPinnedUsage(),
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@ -330,6 +352,7 @@ TEST(CacheReservationManagerWithDelayedDecreaseTest,
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ASSERT_EQ(s, Status::OK());
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ASSERT_EQ(test_cache_rev_mng->GetTotalReservedCacheSize(),
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8 * kSizeDummyEntry);
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ASSERT_EQ(test_cache_rev_mng->GetTotalMemoryUsed(), new_mem_used);
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std::size_t initial_pinned_usage = cache->GetPinnedUsage();
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ASSERT_GE(initial_pinned_usage, 8 * kSizeDummyEntry);
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ASSERT_LT(initial_pinned_usage,
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@ -344,6 +367,8 @@ TEST(CacheReservationManagerWithDelayedDecreaseTest,
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8 * kSizeDummyEntry)
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<< "Failed to bookkeep correctly when delaying cache reservation "
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"decrease";
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EXPECT_EQ(test_cache_rev_mng->GetTotalMemoryUsed(), new_mem_used)
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<< "Failed to bookkeep the used memory correctly";
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EXPECT_EQ(cache->GetPinnedUsage(), initial_pinned_usage)
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<< "Failed to delay decreasing underlying dummy entries in cache";
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@ -356,6 +381,8 @@ TEST(CacheReservationManagerWithDelayedDecreaseTest,
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8 * kSizeDummyEntry)
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<< "Failed to bookkeep correctly when delaying cache reservation "
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"decrease";
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EXPECT_EQ(test_cache_rev_mng->GetTotalMemoryUsed(), new_mem_used)
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<< "Failed to bookkeep the used memory correctly";
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EXPECT_EQ(cache->GetPinnedUsage(), initial_pinned_usage)
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<< "Failed to delay decreasing underlying dummy entries in cache";
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@ -370,6 +397,8 @@ TEST(CacheReservationManagerWithDelayedDecreaseTest,
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6 * kSizeDummyEntry)
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<< "Failed to bookkeep correctly when new_mem_used < "
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"GetTotalReservedCacheSize() * 3 / 4 on delayed decrease mode";
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EXPECT_EQ(test_cache_rev_mng->GetTotalMemoryUsed(), new_mem_used)
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<< "Failed to bookkeep the used memory correctly";
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EXPECT_GE(cache->GetPinnedUsage(), 6 * kSizeDummyEntry)
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<< "Failed to decrease underlying dummy entries in cache when "
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"new_mem_used < GetTotalReservedCacheSize() * 3 / 4 on delayed "
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