1. A method for dynamically adjusting a policy of whether a memory operand access of a memory accessing instruction is to be treated as a transaction atomic access in a transactional execution environment, the method comprising: executing, by a processor, one or more processor-state-setting instructions, the one or more processor-state-setting instructions causing processor first state information to be set in the processor, the processor first state information defined by an instruction set architecture (ISA) of the processor; and beginning execution of a transaction, the execution comprising: executing, by the processor, a transaction-policy-override instruction, the transaction-policy-override instruction causing processor second state information to be set in the processor, the processor second state information defined by the ISA of the processor; based on the processor second state information having a first value, entering a transaction-footprint-override mode; and based on the processor being in transaction-footprint-override mode, any one of ignoring memory conflicts that would otherwise be monitored and monitoring memory conflicts that would otherwise be ignored.