refactor: Remove tiny range from StreamArena

velox/common/memory/HashStringAllocator.h

@@ -290,11 +290,6 @@ class HashStringAllocator : public StreamArena {
   /// Allocates a new range of at least 'bytes' size.
   void newContiguousRange(int32_t bytes, ByteRange* range);
 
-  void newTinyRange(int32_t bytes, ByteRange* lastRange, ByteRange* range)
-      override {
-    newRange(bytes, lastRange, range);
-  }
-
   /// Returns the total memory footprint of 'this'.
   int64_t retainedSize() const {
     return state_.pool().allocatedBytes() + state_.sizeFromPool();

velox/common/memory/StreamArena.cpp

@@ -65,25 +65,13 @@ void StreamArena::newRange(
   }
 }
 
-void StreamArena::newTinyRange(
-    int32_t bytes,
-    ByteRange* /*lastRange*/,
-    ByteRange* range) {
-  VELOX_CHECK_GT(bytes, 0, "StreamArena::newTinyRange can't be zero length");
-  tinyRanges_.emplace_back();
-  tinyRanges_.back().resize(bytes);
-  range->position = 0;
-  range->buffer = reinterpret_cast<uint8_t*>(tinyRanges_.back().data());
-  range->size = bytes;
-}
 void StreamArena::clear() {
   allocations_.clear();
   pool_->freeNonContiguous(allocation_);
   currentRun_ = 0;
   currentOffset_ = 0;
   largeAllocations_.clear();
   size_ = 0;
-  tinyRanges_.clear();
 }
 
 } // namespace facebook::velox

velox/common/memory/StreamArena.h

@@ -44,15 +44,11 @@ class StreamArena {
   /// its last 8 bytes. When extending, we need to update the entry so
   /// that the next pointer is not seen when reading the content and
   /// is also not counted in the payload size of the multipart entry.
+  ///
+  /// NOTE: The method does not guarantee returned 'range' has size of 'bytes',
+  /// it is caller's responsibility to check.
   virtual void newRange(int32_t bytes, ByteRange* lastRange, ByteRange* range);
 
-  /// sets 'range' to point to a small piece of memory owned by this. These
-  /// always come from the heap. The use case is for headers that may change
-  /// length based on data properties, not for bulk data. See 'newRange' for the
-  /// meaning of 'lastRange'.
-  virtual void
-  newTinyRange(int32_t bytes, ByteRange* lastRange, ByteRange* range);
-
   /// Returns the Total size in bytes held by all Allocations.
   virtual size_t size() const {
     return size_;
@@ -68,6 +64,7 @@ class StreamArena {
 
  private:
   memory::MemoryPool* const pool_;
+
   const memory::MachinePageCount allocationQuantum_{2};
 
   // All non-contiguous allocations.
@@ -88,8 +85,6 @@ class StreamArena {
 
   // Tracks all the contiguous and non-contiguous allocations in bytes.
   size_t size_ = 0;
-
-  std::vector<std::string> tinyRanges_;
 };
 
 } // namespace facebook::velox

velox/serializers/VectorStream.h

@@ -68,7 +68,15 @@ class VectorStream {
   }
 
   void initializeHeader(std::string_view name, StreamArena& streamArena) {
-    streamArena.newTinyRange(50, nullptr, &header_);
+    // Allocations from stream arena must be aligned size.
+    const auto headerSize = 64;
+    streamArena.newRange(headerSize, nullptr, &header_);
+    if (header_.size < headerSize) {
+      // StreamArena::newRange() does not guarantee the size. If returned range
+      // does not have enough space, allocate a new one.
+      streamArena.newRange(headerSize, nullptr, &header_);
+      VELOX_CHECK_EQ(header_.size, headerSize);
+    }
     header_.size = name.size() + sizeof(int32_t);
     folly::storeUnaligned<int32_t>(header_.buffer, name.size());
     ::memcpy(header_.buffer + sizeof(int32_t), &name[0], name.size());