RFR: enqueue barrier + some other things

[Roman Kennke]

Am 21.06.2018 um 17:17 schrieb Roland Westrelin:
> 
>> *) This condition in ShenandoahWriteBarrierNode::expand looks odd:
>>
>>  586     if (ShenandoahBarrierSetC2::bsc2()->state()->shenandoah_barriers_count() > 0 ||
>> (!ShenandoahWriteBarrier && ShenandoahStoreValEnqueueBarrier)) {
>>
>> The second part enables when -WB && +SVEB. When this configuration actually manifests? I think
>> Traversal still uses both WB and SVEB.
> 
> I think one0 of the shenandoah jtreg tests tries several different
> combination of flags including -WB +EQ.
> 
>> *) The change to barrierSetC2 should be on our list to upstream. I wonder if boolean parameter
>> should be at the second place:
>>
>>   virtual bool array_copy_requires_gc_barriers(BasicType type, bool tightly_coupled_allocation);
> 
> Actually that part of the change doesn't make any functional change and
> the API will need to be extended to properly cover shenandoah so I won't
> push the array_copy_requires_gc_barriers() changes.
> 
> Roland.
> 

Go for it!
Thanks,
Roman