In one aspect, a process for roll grinding employs a grinding wheel that is porous and permeable. In another aspect, a process for grinding mill rolls includes dressing the grinding wheel as the wheel traverses the surface of a mill roll. Other aspects relate to a system, e.g., a mill roll grinding machine, or parts thereof, in which a dressing tool contacts the wheel as the wheel grinds the surface of the mill roll. In specific examples, the wheel and a rotary dressing tool are maintained in contact as the wheel traverses the surface of the mill roll.