1. An apparatus comprising: execution resources to execute first transaction and a second transaction nested in the first transaction; a monitoring module to detect an invalidating event during execution of the second transaction; a logging module to take a second-level snapshot of a second-level value in a memory location to be changed during execution of the second transaction; and a roll-back module to roll-back the memory location to the second-level snapshot, upon the monitor module detecting an invalidating event during execution of the second transaction.