RFR: ShenandoahWriteBarrierRB flag to conditionally disable RB on WB fastpath

[Roman Kennke]

Am 10.01.2018 um 13:08 schrieb Aleksey Shipilev:
> http://cr.openjdk.java.net/~shade/shenandoah/barrier-disable-wb-fastpath-rb/webrev.01/
> 
> I keep reimplementing this patch during performance investigations. It is sometimes useful to
> dissect the WB cost by measuring if the evac-in-progress check itself, or the RB on the fastpath is
> the reason for performance penalty. New flag allows to do that.
> 
> Testing: hotspot_gc_shenandoah, eyeballing assembly
> 
> Thanks,
> -Aleksey
> 
Ok