RFR (S): 8144714 Add extension point to G1 evacuation closures

[Erik Helin]

On 2015-12-04, Mikael Gerdin wrote:
> Hi all,
> 
> Please review this small change to add a hook in the G1 evacuation path.
> This allows extension code to register regions which are otherwise
> interesting to the GC and get notifications when pointers into such regions
> are encountered.
> 
> Testing: JPRT, gc test suite
> Performance:
> This additional branch in G1ParScanClosure introduces a slight regression of
> about 1-2% in GC pause times. I have some performance fixes to make up for
> that regression in the pipe.
> 
> webrev: http://cr.openjdk.java.net/~mgerdin/8144714/webrev.0/

Looks good, Reviewed.

There seems to be an extra newline at the end of
g1ParScanThreadState_ext.cpp, can you fix that before you push?

Thanks,
Erik

> bug: https://bugs.openjdk.java.net/browse/JDK-8144714
> 
> Thanks
> /Mikael