The G1SATBCT barrier set kind appears to be a left-over from an earlier implementation that did not perform any logging (in either the pre-barrier or post-barrier). Present occurrences of it are very nearly a proper subset of the actually used G1SATBCTLogging barrier kind. The only differences now are that there are some places that either verify (usually by assert) the barrier kind is G1SATBCTLogging, or verify that it is not G1SATBCT. The G1SATBCT barrier set kind should just be eliminated.