This 'adopts' (i.e. mostly copy+pastes) the adaptive thresholds stuff from adaptive heuristics to be used in Traversal GC. Not sure if it should somehow be factored to be shared. http://cr.openjdk.java.net/~rkennke/traversal-adaptive-thresholds/webrev.00/ Testing: tier3_gc_shenandoah, eyeballling logs