Review comments at https://github.com/openjdk/jdk/pull/20395/files#r1698662111 suggest that it might be beneficial to clean up the current implementation of the "preselected" predicate on shenandoah heap regions, used during collection set construction. The code currently creates a resource allocated boolean array indexed by heap regions, representing the predicate, whose lifetime is controlled by a resource mark. While there is no leak (the resource object is created once and freed when the resource mark is exited), it might be sufficient to set and clear a boolean attribute (or heap region state bit) in each region for this purpose without adversely affecting performance. Careful performance comparisons will need to be done, but the resulting clean up will be more maintainable and less awkward code.