8200233: Simple G1 evacuation path performance enhancements Summary: Implement some minor performance optimizations in the evacuation path including changing some stores to be OOP_NOT_NULL, specializing the compressed/uncompressed oops path and delay some load of the current heapregion until absolutely necessary. Reviewed-by: kbarrett, sjohanss

8201365: Remove G1Policy::should_process_references() Reviewed-by: shade

8201247: Various cleanups in the attach framework Reviewed-by: goetz, cjplummer

8200228: Change default value of HeapSizePerGCThread Reviewed-by: tschatzl, shade, jwilhelm

8200195: serviceability/jvmti/FieldAccessWatch/FieldAccessWatch.java crashes with "assert(thread->thread_state() == _thread_in_native) failed: coming from wrong thread state" Reviewed-by: sspitsyn, cjplummer

8194812: Extend class-data sharing to support the module path 8199360: Rework the support for the 'ignored' module options in CDS Reviewed-by: jiangli, lfoltan, iklam, mseledtsov

8198313: Wrap holder object for ClassLoaderData in a WeakHandle Summary: Use WeakHandle for ClassLoaderData::_holder so that is_alive closure is not needed Reviewed-by: rehn, kbarrett

8201321: NMT: Unnecessary re-recording thread stack and size when attaching listener to JavaThread Summary: Replaced recoding thread stack and size with assertion Reviewed-by: dholmes, coleenp

8201334: Move runtime/NMT/MallocStressTest.java to hotspot_tier3_runtime Reviewed-by: lfoltan, mseledtsov, mikael

8201217: Split specialized_oop_closures.hpp into GC specific files Reviewed-by: sjohanss, eosterlund