1. A method of data processing in a data processing system, the method comprising: a processor core generating one or more store operations by executing one or more store instructions in an instruction sequence; selectively marking the store operation as a high priority store operation, wherein the selectively marking includes: marking the one or more store operations as high priority store operations in response to detecting, in the instruction sequence, a window opening instruction and a window closing instruction bounding the one or more store instructions and refraining from marking the one or more store operations as high priority store operations otherwise; buffering the one or more store operations within a store queue associated with a cache memory of the processor core; and expediting handling of the one or more store operations in the store queue in response to the one or more store operations being marked as high priority store operations and otherwise refraining from expediting handling of the one or more store operations in the store queue.