On Wed, Oct 29, 2008 at 01:04:52AM +0900, Roger Pack wrote: > A way to avoid this [as Boehm does (?)] would be to throw up a write > barrier during collection and search it in the parent thread for new > references--I am somewhat scared of doing so since it sounds hard :) Requiring all ObjectSpace methods to grab a mutex and wait for the collector to complete should probably be sufficient. #each_object becomes tricky, because you still want the collector to be invokable when you are iterating over all objects. The easiest solution is to disable #each_object when your patch is enabled. Paul