RFR: 8079275: Remove CollectedHeap::use_parallel_gc_threads

[Kim Barrett]

On May 4, 2015, at 2:33 PM, Stefan Karlsson <stefan.karlsson at oracle.com> wrote:
> 
>> However, I think the class ModUnionClosure is no longer used directly, only as a base class for ModUnionClosurePar and as a type in signatures that always get passed the latter.  If that’s correct, then some class hierarchy cleanup can be done, perhaps with some naming cleanup too.  I’ll keep looking at new versions of this if you want to continue the cleanup here, or you can defer such cleanup to a new CR.  Or you can tell me I missed something.
> 
> It's used in CMSParRemarkTask::do_dirty_card_rescan_tasks and CMSCollector::do_remark_non_parallel.

Oops, you’re right; I didn’t look hard enough.