How does Ruby manage heap fragmentation and compaction in GC?

Ruby GC reduces fragmentation using slot reuse and optional heap compaction strategies.

CRuby allocates objects in fixed-size slots, which reduces external fragmentation. However, internal fragmentation can occur due to uneven object lifetimes. GC reuses freed slots via free lists. Modern Ruby also supports heap compaction, which moves objects to eliminate gaps and improve memory locality, at the cost of pointer updates.