1. A method for implementing memory hierarchy placement decisions in a memory system in a computer system comprising: providing a memory controller in the memory system; providing an in-memory processing element in the memory system; receiving first data from an input output (IO) device and receiving second data exchanged over a network; routing arriving first data and second data directly into the memory system; selectively injecting the first data and the second data into a processor cache; and using one of said memory controller and said in-memory processing element in the memory system, selectively driving data placement into a level of the memory hierarchy based upon the arrival of first data from said input output (IO) device, and from one of computation and a directive of said in-memory processing element.