How does the Go Garbage Collector work?

Go uses a concurrent, tri-color mark-and-sweep garbage collector optimized for low latency.

The GC phase runs concurrently with the application (mutators). It paints objects Black (reachable, scanned), Grey (reachable, unscanned children), or White (unreachable). It scans from root objects (globals, stack vars), turning Grey to Black. Write barriers ensure memory safety if the application modifies pointers during the scan. White objects are then swept (freed).