A computer-implemented method and computer processing system are provided for coordinated heap contraction. The method includes starting a contraction of a heap responsive to a physical memory use of the heap approaching a limit. The contraction starts from a particular runtime system that was estimated to be slowest for the contraction from among a plurality of runtime systems that use the heap, based on previously determined estimates. The method also includes decreasing the physical memory use of the heap by compacting the heap with only one Garbage Collection (GC) thread, responsive to the contraction of the heap being unable to catch up to the physical memory use.