US Patent 7774556 Asymmetric memory migration in hybrid main memory

Main memory is managed by receiving a command from an application to read data associated with a virtual address that is mapped to the main memory. A memory controller determines that the virtual address is mapped to one of the symmetric memory components of the main memory, and accesses memory use characteristics indicating how the data associated with the virtual address has been accessed, The memory controller determines that the data associated with the virtual address has access characteristics suited to an asymmetric memory component of the main memory and loads the data associated with the virtual address to the asymmetric memory component of the main memory. After the loading and using the memory management unit, a command is received from the application to read the data associated with the virtual address, and the data associated with the virtual address is retrieved from the asymmetric memory component.