1. A system comprising: a first processor including at least one core to execute instructions; and a system memory coupled to the first processor, the system memory including instructions that enable the first processor to access, during a transactional memory (TM) transaction, metadata associated with a first predetermined portion of an object stored in the system memory, determine if the metadata includes an address of a shadow copy of the object and if not, perform a first barrier operation on the object, and if the metadata includes the address not perform the first barrier operation, and if the first barrier operation was performed, store the address of the shadow copy of the object in the metadata associated with the first predetermined portion of the object.