Funny seeing this here, as I was just visiting Steve and his students a few days ago as part of my OOPSLA trip. I'm not an expert in this area, but here's my hi

Funny seeing this here, as I was just visiting Steve and his students a few days ago as part of my OOPSLA trip. I'm not an expert in this area, but here's my high level understanding: MMtk is an attempt to define a high performance generic interface for garbage collectors. The idea is that a language implementation can use the MMtk API and then plug in want of a number of garbage collectors, including the state of the art collectors like Immix. If you've ever worked with garbage collectors, you know that garbage collector assumptions tend to be hard wired into the language. And given how important low level implementation details are to GC, it's not obvious that am abstract interface would work. But MMtk shows that's possible.