Technologies relating to efficient memory management for parallel synchronous computing systems are disclosed. Parallel synchronous computing systems may include, for example, a host, a memory management subsystem, and an array of processing units adapted to execute in parallel. Memory management may be implemented at least in part via the memory management subsystem. A memory management subsystem may include one or more memory subsystem layers deployed between the host and the array of processing units. Each memory subsystem layer may have a local memory accessible by entities (whether the host or another layer) above the memory subsystem layer; and a memory controller adapted to manage communications between the entities (whether another layer or the processing units in the array) below the memory subsystem layer.