A data processing system may include a storage unit and a controller in communication with the storage unit and configured to program write data to a first area as at least one of the plurality of storage areas with priority over a second area as at least one of the plurality of storage areas and transfer data of the first area to the second area. The controller is further configured to adjust a size of the first area based on 1) a number of times saturated by the write data for the first area, a saturation occurring due to a size of the write data written to the first area being greater than a certain size and 2) an overflow size of the write data corresponding to a difference between the size of the write data and the certain size.