GetHeapObjectSize in old space contains the size of huge object. In some ways, huge object space belongs to old space. But the committed size of old space and huge object space is independent. Huge object space will be sweeped in old and compress GC. When the engine checks whether it needs old GC or compress GC. It needs to calculate the committed size of old space and huge object space. Then, it decides to trigger Old GC or Compress GC.