1. A system, comprising: one or more processors; and a memory coupled to the one or more processors and comprising program instructions configured to: execute a plurality of transactions operating in a transactional memory space within the memory, wherein the transactional memory space comprises a plurality of locations each associated with one of a plurality of ownership records; wherein the memory further comprises: a global conflict indication comprising a single value indicating whether a read-write conflict has occurred that affects any of the plurality of locations in the transactional memory space, wherein the global conflict indication is accessible by all of the plurality of transactions operating in the transactional memory space; means for semi-transparently reading the transactional memory space, wherein to support semi-transparently reading, the memory is configured to indicate in an ownership record associated with one or more locations in the transactional memory that one or more of the plurality of transactions are reading the one or more locations in the transactional memory space without specifically identifying the one or more transactions; and means for validating transactional reads of the transactional memory space, wherein to validate one or more transactional reads of a given transaction, the means for validating is configured to: determine whether the value of the global conflict indication indicates that a read-write conflict has occurred in the transactional memory space; attempt to validate the one or more transactional reads in response to determining that the value of the global conflict indication indicates that a read-write conflict has occurred in the transactional memory; and allow execution of the given transaction to continue without attempting to validate the one or more transactional reads in response to determining that the value of the global conflict indication indicates that a read-write conflict has not occurred in the transactional memory.