Fix MonotonicBufferResource buffer growth

Reviewers: teon.banek

Reviewed By: teon.banek

Subscribers: pullbot

Differential Revision: https://phabricator.memgraph.io/D2483

src/utils/memory.cpp

@@ -37,10 +37,7 @@ MonotonicBufferResource::MonotonicBufferResource(void *buffer,
                                                  MemoryResource *memory)
     : memory_(memory),
       initial_buffer_(buffer),
-      initial_size_(buffer_size),
-      next_buffer_size_(GrowMonotonicBuffer(
-          initial_size_, std::numeric_limits<size_t>::max() - sizeof(Buffer))) {
-}
+      initial_size_(buffer_size) {}
 
 MonotonicBufferResource::MonotonicBufferResource(
     MonotonicBufferResource &&other) noexcept
@@ -48,6 +45,7 @@ MonotonicBufferResource::MonotonicBufferResource(
       current_buffer_(other.current_buffer_),
       initial_buffer_(other.initial_buffer_),
       initial_size_(other.initial_size_),
+      next_buffer_size_(other.next_buffer_size_),
       allocated_(other.allocated_) {
   other.current_buffer_ = nullptr;
 }
@@ -60,6 +58,7 @@ MonotonicBufferResource &MonotonicBufferResource::operator=(
   current_buffer_ = other.current_buffer_;
   initial_buffer_ = other.initial_buffer_;
   initial_size_ = other.initial_size_;
+  next_buffer_size_ = other.next_buffer_size_;
   allocated_ = other.allocated_;
   other.current_buffer_ = nullptr;
   other.allocated_ = 0U;
@@ -76,6 +75,7 @@ void MonotonicBufferResource::Release() {
     b = next;
   }
   current_buffer_ = nullptr;
+  next_buffer_size_ = initial_size_;
   allocated_ = 0U;
 }
 

tests/unit/utils_memory.cpp

@@ -329,6 +329,39 @@ TEST(PoolResource, BlockDeallocation) {
   EXPECT_EQ(test_mem.new_count_, 0U);
 }
 
+class AllocationTrackingMemory final : public utils::MemoryResource {
+ public:
+  std::vector<size_t> allocated_sizes_;
+
+ private:
+  void *DoAllocate(size_t bytes, size_t alignment) override {
+    allocated_sizes_.push_back(bytes);
+    return utils::NewDeleteResource()->Allocate(bytes, alignment);
+  }
+
+  void DoDeallocate(void *ptr, size_t bytes, size_t alignment) override {
+    return utils::NewDeleteResource()->Deallocate(ptr, bytes, alignment);
+  }
+
+  bool DoIsEqual(const utils::MemoryResource &other) const noexcept override {
+    return this == &other;
+  }
+};
+
+// NOLINTNEXTLINE(hicpp-special-member-functions)
+TEST(MonotonicBufferResource, ResetGrowthFactor) {
+  AllocationTrackingMemory test_mem;
+  constexpr size_t stack_data_size = 1024;
+  char stack_data[stack_data_size];
+  utils::MonotonicBufferResource mem(&stack_data[0], stack_data_size,
+                                     &test_mem);
+  mem.Allocate(stack_data_size + 1);
+  mem.Release();
+  mem.Allocate(stack_data_size + 1);
+  ASSERT_EQ(test_mem.allocated_sizes_.size(), 2);
+  ASSERT_EQ(test_mem.allocated_sizes_.front(), test_mem.allocated_sizes_.back());
+}
+
 // NOLINTNEXTLINE(hicpp-special-member-functions)
 class ContainerWithAllocatorLast final {
  public: