[Rohansi]

Also, if you'd like to know of an earlier example, the very first Raspberry Pi has fully unified memory. Released 2012, SoC from 2011. It's not exposed in the usual APIs which is why you have a configurable RAM allocation for the GPU, so you need to write special code targeting the GPU cores. You can pass a pointer from the CPU and have the GPU read data directly. Results are written back to RAM which can be read by the CPU.