1. A method of instruction cache (I-cache) management, comprising: maintaining a different substantially random instruction mapping policy into an I-cache for each of multiple processes; and for each process, performing a substantially random mapping scheme for mapping a process instruction into the I-cache based on the substantially random instruction mapping policy for said process; wherein said multiple processes include security critical process instructions, such that maintaining a different substantially random instruction mapping policy into an I-cache for each of multiple processes includes maintaining a different substantially random instruction mapping policy into the I-cache for each of multiple security critical processes.