Garbage collection of objects within the heap of a computing system, and movement of adjacent sets of live objects as a whole in order to perform compaction. The compaction may be performed even if there are adjacent sets of live objects that include one or more pinned objects that should not be moved by the garbage collector. The garbage collector uses gaps to include relocation information with respect to sets of adjacent objects of the same pinned status. Some gaps may be formulated by writing over the live objects themselves, in which case that written over data is saved off prior to formulating the gap. When compaction is performed, the saved off data is used to fully integrate the adjacent objects of the same pinned status in the process of compaction.