The reason for a bus-style IPC implemented in the kernel is the same that sendfile(2) exists. I doubt anyone thinks it's the pinnacle of great design, but redu

The reason for a bus-style IPC implemented in the kernel is the same that sendfile(2) exists. I doubt anyone thinks it's the pinnacle of great design, but reduced copies and context switching for real application workload: sometimes the more 'proper' design is sacrificed for practicality.