1. A method for allocating computing resources on a parallel computing system having a plurality of compute nodes, each node compute node having at least one processor, the method comprising: suspending one or more of a plurality of computing jobs being executed on the parallel computing system, wherein each computing job is being executed on a block of compute nodes provided by the parallel computing system; moving each of the one or more suspended computing jobs to another block of compute nodes of the parallel system, whereby a space of available compute nodes provided by the parallel computing system is defragmented; and resuming execution of the one or more suspended jobs on the parallel computing system.