If there is enough space in the heap to satisfy a memory request, it can be handled by the language runtime without kernel involvement.

It focuses on scalability and response time improvements, looking to enhance interfaces across vertical component and system stacks (e.g. runtime, kernel, OS, hyperviser).

It's unclear why they made this change; possibly they found that most drivers didn't use the features of Objective-C, or possibly they just wanted to move the Objective-C runtime out of the kernel.