RFR (7xS): 8177707: Specialize G1RemSet::refine_card for concurrent/during safepoint refinement

[Kim Barrett]

> On May 5, 2017, at 7:52 AM, Thomas Schatzl <thomas.schatzl at oracle.com> wrote:
> 
> New webrevs:
> http://cr.openjdk.java.net/~tschatzl/8177707/webrev.0_to_1/ (diff)
> http://cr.openjdk.java.net/~tschatzl/8177707/webrev.1/ (full)
> 
> Thanks,
>   Thomas

Looks good.