RFR (M): 8201491: G1 support for java.lang.ref.Reference precleaning

[Kim Barrett]

> On Apr 26, 2018, at 5:36 AM, Thomas Schatzl <thomas.schatzl at oracle.com> wrote:
> 
> Hi all,
> 
>  can I have reviews for this change that implements reference
> precleaning like CMS for G1?
> 
> […]
> CR:
> https://bugs.openjdk.java.net/browse/JDK-8201491
> Webrev:
> http://cr.openjdk.java.net/~tschatzl/8201491/webrev/
> Testing:
> hs-tier1-5, *many* times Kitchensink reference stress test
> 
> Thanks,
>  Thomas

Looks good.