1 files changed, 469 insertions, 0 deletions
diff --git a/src/rocksdb/cache/cache_reservation_manager_test.cc b/src/rocksdb/cache/cache_reservation_manager_test.cc
new file mode 100644
index 000000000..2a0c318e0
--- /dev/null
+++ b/src/rocksdb/cache/cache_reservation_manager_test.cc
@@ -0,0 +1,469 @@
+//  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.
+#include "cache/cache_reservation_manager.h"
+
+#include <cstddef>
+#include <cstring>
+#include <memory>
+
+#include "cache/cache_entry_roles.h"
+#include "rocksdb/cache.h"
+#include "rocksdb/slice.h"
+#include "test_util/testharness.h"
+#include "util/coding.h"
+
+namespace ROCKSDB_NAMESPACE {
+class CacheReservationManagerTest : public ::testing::Test {
+ protected:
+  static constexpr std::size_t kSizeDummyEntry =
+      CacheReservationManagerImpl<CacheEntryRole::kMisc>::GetDummyEntrySize();
+  static constexpr std::size_t kCacheCapacity = 4096 * kSizeDummyEntry;
+  static constexpr int kNumShardBits = 0;  // 2^0 shard
+  static constexpr std::size_t kMetaDataChargeOverhead = 10000;
+
+  std::shared_ptr<Cache> cache = NewLRUCache(kCacheCapacity, kNumShardBits);
+  std::shared_ptr<CacheReservationManager> test_cache_rev_mng;
+
+  CacheReservationManagerTest() {
+    test_cache_rev_mng =
+        std::make_shared<CacheReservationManagerImpl<CacheEntryRole::kMisc>>(
+            cache);
+  }
+};
+
+TEST_F(CacheReservationManagerTest, GenerateCacheKey) {
+  std::size_t new_mem_used = 1 * kSizeDummyEntry;
+  Status s = test_cache_rev_mng->UpdateCacheReservation(new_mem_used);
+  ASSERT_EQ(s, Status::OK());
+  ASSERT_GE(cache->GetPinnedUsage(), 1 * kSizeDummyEntry);
+  ASSERT_LT(cache->GetPinnedUsage(),
+            1 * kSizeDummyEntry + kMetaDataChargeOverhead);
+
+  // Next unique Cache key
+  CacheKey ckey = CacheKey::CreateUniqueForCacheLifetime(cache.get());
+  // Get to the underlying values
+  uint64_t* ckey_data = reinterpret_cast<uint64_t*>(&ckey);
+  // Back it up to the one used by CRM (using CacheKey implementation details)
+  ckey_data[1]--;
+
+  // Specific key (subject to implementation details)
+  EXPECT_EQ(ckey_data[0], 0);
+  EXPECT_EQ(ckey_data[1], 2);
+
+  Cache::Handle* handle = cache->Lookup(ckey.AsSlice());
+  EXPECT_NE(handle, nullptr)
+      << "Failed to generate the cache key for the dummy entry correctly";
+  // Clean up the returned handle from Lookup() to prevent memory leak
+  cache->Release(handle);
+}
+
+TEST_F(CacheReservationManagerTest, KeepCacheReservationTheSame) {
+  std::size_t new_mem_used = 1 * kSizeDummyEntry;
+  Status s = test_cache_rev_mng->UpdateCacheReservation(new_mem_used);
+  ASSERT_EQ(s, Status::OK());
+  ASSERT_EQ(test_cache_rev_mng->GetTotalReservedCacheSize(),
+            1 * kSizeDummyEntry);
+  ASSERT_EQ(test_cache_rev_mng->GetTotalMemoryUsed(), new_mem_used);
+  std::size_t initial_pinned_usage = cache->GetPinnedUsage();
+  ASSERT_GE(initial_pinned_usage, 1 * kSizeDummyEntry);
+  ASSERT_LT(initial_pinned_usage,
+            1 * kSizeDummyEntry + kMetaDataChargeOverhead);
+
+  s = test_cache_rev_mng->UpdateCacheReservation(new_mem_used);
+  EXPECT_EQ(s, Status::OK())
+      << "Failed to keep cache reservation the same when new_mem_used equals "
+         "to current cache reservation";
+  EXPECT_EQ(test_cache_rev_mng->GetTotalReservedCacheSize(),
+            1 * kSizeDummyEntry)
+      << "Failed to bookkeep correctly when new_mem_used equals to current "
+         "cache reservation";
+  EXPECT_EQ(test_cache_rev_mng->GetTotalMemoryUsed(), new_mem_used)
+      << "Failed to bookkeep the used memory correctly when new_mem_used "
+         "equals to current cache reservation";
+  EXPECT_EQ(cache->GetPinnedUsage(), initial_pinned_usage)
+      << "Failed to keep underlying dummy entries the same when new_mem_used "
+         "equals to current cache reservation";
+}
+
+TEST_F(CacheReservationManagerTest,
+       IncreaseCacheReservationByMultiplesOfDummyEntrySize) {
+  std::size_t new_mem_used = 2 * kSizeDummyEntry;
+  Status s = test_cache_rev_mng->UpdateCacheReservation(new_mem_used);
+  EXPECT_EQ(s, Status::OK())
+      << "Failed to increase cache reservation correctly";
+  EXPECT_EQ(test_cache_rev_mng->GetTotalReservedCacheSize(),
+            2 * kSizeDummyEntry)
+      << "Failed to bookkeep cache reservation increase correctly";
+  EXPECT_EQ(test_cache_rev_mng->GetTotalMemoryUsed(), new_mem_used)
+      << "Failed to bookkeep the used memory correctly";
+  EXPECT_GE(cache->GetPinnedUsage(), 2 * kSizeDummyEntry)
+      << "Failed to increase underlying dummy entries in cache correctly";
+  EXPECT_LT(cache->GetPinnedUsage(),
+            2 * kSizeDummyEntry + kMetaDataChargeOverhead)
+      << "Failed to increase underlying dummy entries in cache correctly";
+}
+
+TEST_F(CacheReservationManagerTest,
+       IncreaseCacheReservationNotByMultiplesOfDummyEntrySize) {
+  std::size_t new_mem_used = 2 * kSizeDummyEntry + kSizeDummyEntry / 2;
+  Status s = test_cache_rev_mng->UpdateCacheReservation(new_mem_used);
+  EXPECT_EQ(s, Status::OK())
+      << "Failed to increase cache reservation correctly";
+  EXPECT_EQ(test_cache_rev_mng->GetTotalReservedCacheSize(),
+            3 * kSizeDummyEntry)
+      << "Failed to bookkeep cache reservation increase correctly";
+  EXPECT_EQ(test_cache_rev_mng->GetTotalMemoryUsed(), new_mem_used)
+      << "Failed to bookkeep the used memory correctly";
+  EXPECT_GE(cache->GetPinnedUsage(), 3 * kSizeDummyEntry)
+      << "Failed to increase underlying dummy entries in cache correctly";
+  EXPECT_LT(cache->GetPinnedUsage(),
+            3 * kSizeDummyEntry + kMetaDataChargeOverhead)
+      << "Failed to increase underlying dummy entries in cache correctly";
+}
+
+TEST(CacheReservationManagerIncreaseReservcationOnFullCacheTest,
+     IncreaseCacheReservationOnFullCache) {
+  ;
+  constexpr std::size_t kSizeDummyEntry =
+      CacheReservationManagerImpl<CacheEntryRole::kMisc>::GetDummyEntrySize();
+  constexpr std::size_t kSmallCacheCapacity = 4 * kSizeDummyEntry;
+  constexpr std::size_t kBigCacheCapacity = 4096 * kSizeDummyEntry;
+  constexpr std::size_t kMetaDataChargeOverhead = 10000;
+
+  LRUCacheOptions lo;
+  lo.capacity = kSmallCacheCapacity;
+  lo.num_shard_bits = 0;  // 2^0 shard
+  lo.strict_capacity_limit = true;
+  std::shared_ptr<Cache> cache = NewLRUCache(lo);
+  std::shared_ptr<CacheReservationManager> test_cache_rev_mng =
+      std::make_shared<CacheReservationManagerImpl<CacheEntryRole::kMisc>>(
+          cache);
+
+  std::size_t new_mem_used = kSmallCacheCapacity + 1;
+  Status s = test_cache_rev_mng->UpdateCacheReservation(new_mem_used);
+  EXPECT_EQ(s, Status::MemoryLimit())
+      << "Failed to return status to indicate failure of dummy entry insertion "
+         "during cache reservation on full cache";
+  EXPECT_GE(test_cache_rev_mng->GetTotalReservedCacheSize(),
+            1 * kSizeDummyEntry)
+      << "Failed to bookkeep correctly before cache resevation failure happens "
+         "due to full cache";
+  EXPECT_LE(test_cache_rev_mng->GetTotalReservedCacheSize(),
+            kSmallCacheCapacity)
+      << "Failed to bookkeep correctly (i.e, bookkeep only successful dummy "
+         "entry insertions) when encountering cache resevation failure due to "
+         "full cache";
+  EXPECT_EQ(test_cache_rev_mng->GetTotalMemoryUsed(), new_mem_used)
+      << "Failed to bookkeep the used memory correctly";
+  EXPECT_GE(cache->GetPinnedUsage(), 1 * kSizeDummyEntry)
+      << "Failed to insert underlying dummy entries correctly when "
+         "encountering cache resevation failure due to full cache";
+  EXPECT_LE(cache->GetPinnedUsage(), kSmallCacheCapacity)
+      << "Failed to insert underlying dummy entries correctly when "
+         "encountering cache resevation failure due to full cache";
+
+  new_mem_used = kSmallCacheCapacity / 2;  // 2 dummy entries
+  s = test_cache_rev_mng->UpdateCacheReservation(new_mem_used);
+  EXPECT_EQ(s, Status::OK())
+      << "Failed to decrease cache reservation after encountering cache "
+         "reservation failure due to full cache";
+  EXPECT_EQ(test_cache_rev_mng->GetTotalReservedCacheSize(),
+            2 * kSizeDummyEntry)
+      << "Failed to bookkeep cache reservation decrease correctly after "
+         "encountering cache reservation due to full cache";
+  EXPECT_EQ(test_cache_rev_mng->GetTotalMemoryUsed(), new_mem_used)
+      << "Failed to bookkeep the used memory correctly";
+  EXPECT_GE(cache->GetPinnedUsage(), 2 * kSizeDummyEntry)
+      << "Failed to release underlying dummy entries correctly on cache "
+         "reservation decrease after encountering cache resevation failure due "
+         "to full cache";
+  EXPECT_LT(cache->GetPinnedUsage(),
+            2 * kSizeDummyEntry + kMetaDataChargeOverhead)
+      << "Failed to release underlying dummy entries correctly on cache "
+         "reservation decrease after encountering cache resevation failure due "
+         "to full cache";
+
+  // Create cache full again for subsequent tests
+  new_mem_used = kSmallCacheCapacity + 1;
+  s = test_cache_rev_mng->UpdateCacheReservation(new_mem_used);
+  EXPECT_EQ(s, Status::MemoryLimit())
+      << "Failed to return status to indicate failure of dummy entry insertion "
+         "during cache reservation on full cache";
+  EXPECT_GE(test_cache_rev_mng->GetTotalReservedCacheSize(),
+            1 * kSizeDummyEntry)
+      << "Failed to bookkeep correctly before cache resevation failure happens "
+         "due to full cache";
+  EXPECT_LE(test_cache_rev_mng->GetTotalReservedCacheSize(),
+            kSmallCacheCapacity)
+      << "Failed to bookkeep correctly (i.e, bookkeep only successful dummy "
+         "entry insertions) when encountering cache resevation failure due to "
+         "full cache";
+  EXPECT_EQ(test_cache_rev_mng->GetTotalMemoryUsed(), new_mem_used)
+      << "Failed to bookkeep the used memory correctly";
+  EXPECT_GE(cache->GetPinnedUsage(), 1 * kSizeDummyEntry)
+      << "Failed to insert underlying dummy entries correctly when "
+         "encountering cache resevation failure due to full cache";
+  EXPECT_LE(cache->GetPinnedUsage(), kSmallCacheCapacity)
+      << "Failed to insert underlying dummy entries correctly when "
+         "encountering cache resevation failure due to full cache";
+
+  // Increase cache capacity so the previously failed insertion can fully
+  // succeed
+  cache->SetCapacity(kBigCacheCapacity);
+  new_mem_used = kSmallCacheCapacity + 1;
+  s = test_cache_rev_mng->UpdateCacheReservation(new_mem_used);
+  EXPECT_EQ(s, Status::OK())
+      << "Failed to increase cache reservation after increasing cache capacity "
+         "and mitigating cache full error";
+  EXPECT_EQ(test_cache_rev_mng->GetTotalReservedCacheSize(),
+            5 * kSizeDummyEntry)
+      << "Failed to bookkeep cache reservation increase correctly after "
+         "increasing cache capacity and mitigating cache full error";
+  EXPECT_EQ(test_cache_rev_mng->GetTotalMemoryUsed(), new_mem_used)
+      << "Failed to bookkeep the used memory correctly";
+  EXPECT_GE(cache->GetPinnedUsage(), 5 * kSizeDummyEntry)
+      << "Failed to insert underlying dummy entries correctly after increasing "
+         "cache capacity and mitigating cache full error";
+  EXPECT_LT(cache->GetPinnedUsage(),
+            5 * kSizeDummyEntry + kMetaDataChargeOverhead)
+      << "Failed to insert underlying dummy entries correctly after increasing "
+         "cache capacity and mitigating cache full error";
+}
+
+TEST_F(CacheReservationManagerTest,
+       DecreaseCacheReservationByMultiplesOfDummyEntrySize) {
+  std::size_t new_mem_used = 2 * kSizeDummyEntry;
+  Status s = test_cache_rev_mng->UpdateCacheReservation(new_mem_used);
+  ASSERT_EQ(s, Status::OK());
+  ASSERT_EQ(test_cache_rev_mng->GetTotalReservedCacheSize(),
+            2 * kSizeDummyEntry);
+  ASSERT_EQ(test_cache_rev_mng->GetTotalMemoryUsed(), new_mem_used);
+  ASSERT_GE(cache->GetPinnedUsage(), 2 * kSizeDummyEntry);
+  ASSERT_LT(cache->GetPinnedUsage(),
+            2 * kSizeDummyEntry + kMetaDataChargeOverhead);
+
+  new_mem_used = 1 * kSizeDummyEntry;
+  s = test_cache_rev_mng->UpdateCacheReservation(new_mem_used);
+  EXPECT_EQ(s, Status::OK())
+      << "Failed to decrease cache reservation correctly";
+  EXPECT_EQ(test_cache_rev_mng->GetTotalReservedCacheSize(),
+            1 * kSizeDummyEntry)
+      << "Failed to bookkeep cache reservation decrease correctly";
+  EXPECT_EQ(test_cache_rev_mng->GetTotalMemoryUsed(), new_mem_used)
+      << "Failed to bookkeep the used memory correctly";
+  EXPECT_GE(cache->GetPinnedUsage(), 1 * kSizeDummyEntry)
+      << "Failed to decrease underlying dummy entries in cache correctly";
+  EXPECT_LT(cache->GetPinnedUsage(),
+            1 * kSizeDummyEntry + kMetaDataChargeOverhead)
+      << "Failed to decrease underlying dummy entries in cache correctly";
+}
+
+TEST_F(CacheReservationManagerTest,
+       DecreaseCacheReservationNotByMultiplesOfDummyEntrySize) {
+  std::size_t new_mem_used = 2 * kSizeDummyEntry;
+  Status s = test_cache_rev_mng->UpdateCacheReservation(new_mem_used);
+  ASSERT_EQ(s, Status::OK());
+  ASSERT_EQ(test_cache_rev_mng->GetTotalReservedCacheSize(),
+            2 * kSizeDummyEntry);
+  ASSERT_EQ(test_cache_rev_mng->GetTotalMemoryUsed(), new_mem_used);
+  ASSERT_GE(cache->GetPinnedUsage(), 2 * kSizeDummyEntry);
+  ASSERT_LT(cache->GetPinnedUsage(),
+            2 * kSizeDummyEntry + kMetaDataChargeOverhead);
+
+  new_mem_used = kSizeDummyEntry / 2;
+  s = test_cache_rev_mng->UpdateCacheReservation(new_mem_used);
+  EXPECT_EQ(s, Status::OK())
+      << "Failed to decrease cache reservation correctly";
+  EXPECT_EQ(test_cache_rev_mng->GetTotalReservedCacheSize(),
+            1 * kSizeDummyEntry)
+      << "Failed to bookkeep cache reservation decrease correctly";
+  EXPECT_EQ(test_cache_rev_mng->GetTotalMemoryUsed(), new_mem_used)
+      << "Failed to bookkeep the used memory correctly";
+  EXPECT_GE(cache->GetPinnedUsage(), 1 * kSizeDummyEntry)
+      << "Failed to decrease underlying dummy entries in cache correctly";
+  EXPECT_LT(cache->GetPinnedUsage(),
+            1 * kSizeDummyEntry + kMetaDataChargeOverhead)
+      << "Failed to decrease underlying dummy entries in cache correctly";
+}
+
+TEST(CacheReservationManagerWithDelayedDecreaseTest,
+     DecreaseCacheReservationWithDelayedDecrease) {
+  constexpr std::size_t kSizeDummyEntry =
+      CacheReservationManagerImpl<CacheEntryRole::kMisc>::GetDummyEntrySize();
+  constexpr std::size_t kCacheCapacity = 4096 * kSizeDummyEntry;
+  constexpr std::size_t kMetaDataChargeOverhead = 10000;
+
+  LRUCacheOptions lo;
+  lo.capacity = kCacheCapacity;
+  lo.num_shard_bits = 0;
+  std::shared_ptr<Cache> cache = NewLRUCache(lo);
+  std::shared_ptr<CacheReservationManager> test_cache_rev_mng =
+      std::make_shared<CacheReservationManagerImpl<CacheEntryRole::kMisc>>(
+          cache, true /* delayed_decrease */);
+
+  std::size_t new_mem_used = 8 * kSizeDummyEntry;
+  Status s = test_cache_rev_mng->UpdateCacheReservation(new_mem_used);
+  ASSERT_EQ(s, Status::OK());
+  ASSERT_EQ(test_cache_rev_mng->GetTotalReservedCacheSize(),
+            8 * kSizeDummyEntry);
+  ASSERT_EQ(test_cache_rev_mng->GetTotalMemoryUsed(), new_mem_used);
+  std::size_t initial_pinned_usage = cache->GetPinnedUsage();
+  ASSERT_GE(initial_pinned_usage, 8 * kSizeDummyEntry);
+  ASSERT_LT(initial_pinned_usage,
+            8 * kSizeDummyEntry + kMetaDataChargeOverhead);
+
+  new_mem_used = 6 * kSizeDummyEntry;
+  s = test_cache_rev_mng->UpdateCacheReservation(new_mem_used);
+  EXPECT_EQ(s, Status::OK()) << "Failed to delay decreasing cache reservation";
+  EXPECT_EQ(test_cache_rev_mng->GetTotalReservedCacheSize(),
+            8 * kSizeDummyEntry)
+      << "Failed to bookkeep correctly when delaying cache reservation "
+         "decrease";
+  EXPECT_EQ(test_cache_rev_mng->GetTotalMemoryUsed(), new_mem_used)
+      << "Failed to bookkeep the used memory correctly";
+  EXPECT_EQ(cache->GetPinnedUsage(), initial_pinned_usage)
+      << "Failed to delay decreasing underlying dummy entries in cache";
+
+  new_mem_used = 7 * kSizeDummyEntry;
+  s = test_cache_rev_mng->UpdateCacheReservation(new_mem_used);
+  EXPECT_EQ(s, Status::OK()) << "Failed to delay decreasing cache reservation";
+  EXPECT_EQ(test_cache_rev_mng->GetTotalReservedCacheSize(),
+            8 * kSizeDummyEntry)
+      << "Failed to bookkeep correctly when delaying cache reservation "
+         "decrease";
+  EXPECT_EQ(test_cache_rev_mng->GetTotalMemoryUsed(), new_mem_used)
+      << "Failed to bookkeep the used memory correctly";
+  EXPECT_EQ(cache->GetPinnedUsage(), initial_pinned_usage)
+      << "Failed to delay decreasing underlying dummy entries in cache";
+
+  new_mem_used = 6 * kSizeDummyEntry - 1;
+  s = test_cache_rev_mng->UpdateCacheReservation(new_mem_used);
+  EXPECT_EQ(s, Status::OK())
+      << "Failed to decrease cache reservation correctly when new_mem_used < "
+         "GetTotalReservedCacheSize() * 3 / 4 on delayed decrease mode";
+  EXPECT_EQ(test_cache_rev_mng->GetTotalReservedCacheSize(),
+            6 * kSizeDummyEntry)
+      << "Failed to bookkeep correctly when new_mem_used < "
+         "GetTotalReservedCacheSize() * 3 / 4 on delayed decrease mode";
+  EXPECT_EQ(test_cache_rev_mng->GetTotalMemoryUsed(), new_mem_used)
+      << "Failed to bookkeep the used memory correctly";
+  EXPECT_GE(cache->GetPinnedUsage(), 6 * kSizeDummyEntry)
+      << "Failed to decrease underlying dummy entries in cache when "
+         "new_mem_used < GetTotalReservedCacheSize() * 3 / 4 on delayed "
+         "decrease mode";
+  EXPECT_LT(cache->GetPinnedUsage(),
+            6 * kSizeDummyEntry + kMetaDataChargeOverhead)
+      << "Failed to decrease underlying dummy entries in cache when "
+         "new_mem_used < GetTotalReservedCacheSize() * 3 / 4 on delayed "
+         "decrease mode";
+}
+
+TEST(CacheReservationManagerDestructorTest,
+     ReleaseRemainingDummyEntriesOnDestruction) {
+  constexpr std::size_t kSizeDummyEntry =
+      CacheReservationManagerImpl<CacheEntryRole::kMisc>::GetDummyEntrySize();
+  constexpr std::size_t kCacheCapacity = 4096 * kSizeDummyEntry;
+  constexpr std::size_t kMetaDataChargeOverhead = 10000;
+
+  LRUCacheOptions lo;
+  lo.capacity = kCacheCapacity;
+  lo.num_shard_bits = 0;
+  std::shared_ptr<Cache> cache = NewLRUCache(lo);
+  {
+    std::shared_ptr<CacheReservationManager> test_cache_rev_mng =
+        std::make_shared<CacheReservationManagerImpl<CacheEntryRole::kMisc>>(
+            cache);
+    std::size_t new_mem_used = 1 * kSizeDummyEntry;
+    Status s = test_cache_rev_mng->UpdateCacheReservation(new_mem_used);
+    ASSERT_EQ(s, Status::OK());
+    ASSERT_GE(cache->GetPinnedUsage(), 1 * kSizeDummyEntry);
+    ASSERT_LT(cache->GetPinnedUsage(),
+              1 * kSizeDummyEntry + kMetaDataChargeOverhead);
+  }
+  EXPECT_EQ(cache->GetPinnedUsage(), 0 * kSizeDummyEntry)
+      << "Failed to release remaining underlying dummy entries in cache in "
+         "CacheReservationManager's destructor";
+}
+
+TEST(CacheReservationHandleTest, HandleTest) {
+  constexpr std::size_t kOneGigabyte = 1024 * 1024 * 1024;
+  constexpr std::size_t kSizeDummyEntry = 256 * 1024;
+  constexpr std::size_t kMetaDataChargeOverhead = 10000;
+
+  LRUCacheOptions lo;
+  lo.capacity = kOneGigabyte;
+  lo.num_shard_bits = 0;
+  std::shared_ptr<Cache> cache = NewLRUCache(lo);
+
+  std::shared_ptr<CacheReservationManager> test_cache_rev_mng(
+      std::make_shared<CacheReservationManagerImpl<CacheEntryRole::kMisc>>(
+          cache));
+
+  std::size_t mem_used = 0;
+  const std::size_t incremental_mem_used_handle_1 = 1 * kSizeDummyEntry;
+  const std::size_t incremental_mem_used_handle_2 = 2 * kSizeDummyEntry;
+  std::unique_ptr<CacheReservationManager::CacheReservationHandle> handle_1,
+      handle_2;
+
+  // To test consecutive CacheReservationManager::MakeCacheReservation works
+  // correctly in terms of returning the handle as well as updating cache
+  // reservation and the latest total memory used
+  Status s = test_cache_rev_mng->MakeCacheReservation(
+      incremental_mem_used_handle_1, &handle_1);
+  mem_used = mem_used + incremental_mem_used_handle_1;
+  ASSERT_EQ(s, Status::OK());
+  EXPECT_TRUE(handle_1 != nullptr);
+  EXPECT_EQ(test_cache_rev_mng->GetTotalReservedCacheSize(), mem_used);
+  EXPECT_EQ(test_cache_rev_mng->GetTotalMemoryUsed(), mem_used);
+  EXPECT_GE(cache->GetPinnedUsage(), mem_used);
+  EXPECT_LT(cache->GetPinnedUsage(), mem_used + kMetaDataChargeOverhead);
+
+  s = test_cache_rev_mng->MakeCacheReservation(incremental_mem_used_handle_2,
+                                               &handle_2);
+  mem_used = mem_used + incremental_mem_used_handle_2;
+  ASSERT_EQ(s, Status::OK());
+  EXPECT_TRUE(handle_2 != nullptr);
+  EXPECT_EQ(test_cache_rev_mng->GetTotalReservedCacheSize(), mem_used);
+  EXPECT_EQ(test_cache_rev_mng->GetTotalMemoryUsed(), mem_used);
+  EXPECT_GE(cache->GetPinnedUsage(), mem_used);
+  EXPECT_LT(cache->GetPinnedUsage(), mem_used + kMetaDataChargeOverhead);
+
+  // To test
+  // CacheReservationManager::CacheReservationHandle::~CacheReservationHandle()
+  // works correctly in releasing the cache reserved for the handle
+  handle_1.reset();
+  EXPECT_TRUE(handle_1 == nullptr);
+  mem_used = mem_used - incremental_mem_used_handle_1;
+  EXPECT_EQ(test_cache_rev_mng->GetTotalReservedCacheSize(), mem_used);
+  EXPECT_EQ(test_cache_rev_mng->GetTotalMemoryUsed(), mem_used);
+  EXPECT_GE(cache->GetPinnedUsage(), mem_used);
+  EXPECT_LT(cache->GetPinnedUsage(), mem_used + kMetaDataChargeOverhead);
+
+  // To test the actual CacheReservationManager object won't be deallocated
+  // as long as there remain handles pointing to it.
+  // We strongly recommend deallocating CacheReservationManager object only
+  // after all its handles are deallocated to keep things easy to reasonate
+  test_cache_rev_mng.reset();
+  EXPECT_GE(cache->GetPinnedUsage(), mem_used);
+  EXPECT_LT(cache->GetPinnedUsage(), mem_used + kMetaDataChargeOverhead);
+
+  handle_2.reset();
+  // The CacheReservationManager object is now deallocated since all the handles
+  // and its original pointer is gone
+  mem_used = mem_used - incremental_mem_used_handle_2;
+  EXPECT_EQ(mem_used, 0);
+  EXPECT_EQ(cache->GetPinnedUsage(), mem_used);
+}
+}  // namespace ROCKSDB_NAMESPACE
+
+int main(int argc, char** argv) {
+  ROCKSDB_NAMESPACE::port::InstallStackTraceHandler();
+  ::testing::InitGoogleTest(&argc, argv);
+  return RUN_ALL_TESTS();
+}