1. A computer-implemented method, comprising: determining whether an indication of ownership for a portion of a shared data structure indicates a software-mode or a transactional-mode for modifying the portion of a shared data structure, wherein a block of shared memory represents current data of the portion of the shared data structure; attempting to modify a value of the portion of a shared data structure using a transaction if the indication of ownership indicates the transactional-mode; and attempting to modify the value of the portion of a shared data structure using software operations if the indication of ownership indicates the software-mode.