Constrained transaction execution

A method of processing transactions within a computing environment, said method comprising:nobtaining, by a processor, a machine instruction, the machine instruction to initiate a transaction of a specified type, the specified type explicitly indicated in a field of the machine instruction;executing, by the processor, the transaction initiated by the machine instruction, the transaction effectively delaying committing transactional stores to main memory until completion of a selected transaction;determining, based on executing the transaction, that an abort condition has occurred;checking whether the specified type of transaction is a constrained transaction, the constrained transaction having one or more restrictions associated therewith, and the checking comprising checking the field of the machine instruction to determine whether the transaction is a constrained transaction; andperforming processing based on determining the abort condition and dependent on the specified type of transaction, wherein based on the checking indicating the transaction is a constrained transaction and based on the abort condition being a particular type of abort condition, the performing processing comprising returning to a beginning of the transaction to re-execute the transaction, and wherein a fail path, other than returning to the beginning of the transaction, is not provided to handle the abort condition.