RFR: 8209376: ZGC: Move ZMarkStackAllocator into a separate file

[Erik Österlund]

Hi Per,

Looks good.

Thanks,
/Erik

On 2018-08-13 09:53, Per Liden wrote:
> Break out the mark stack allocation logic from ZMarkStack.[ch]pp into 
> ZMarkStackAllocator.[ch].pp.
>
> Bug: https://bugs.openjdk.java.net/browse/JDK-8209376
> Webrev: http://cr.openjdk.java.net/~pliden/8209376/webrev.0
>
> /Per