RFR (M): 8235860: Obsolete the UseParallelOldGC option

[Kim Barrett]

> On Dec 18, 2019, at 4:52 AM, Thomas Schatzl <thomas.schatzl at oracle.com> wrote:
> 
> Fixed in
> http://cr.openjdk.java.net/~tschatzl/8235860/webrev.0_to_1 (diff)
> http://cr.openjdk.java.net/~tschatzl/8235860/webrev.1 (full)

Looks good.

> 
>> ------------------------------------------------------------------------------
>> src/hotspot/share/gc/parallel/psParallelCompact.hpp
>> Pre-existing: It seems like the big block comment before SplitInfo
>> should have received some updates as part of the recent shadow-region
>> patch, but it wasn't touched.
>> ------------------------------------------------------------------------------
> 
> I am filing a CR for that.

The comment before PSParallelCompact in the same file might also need some updating.

(I was a bit confused in my earlier review about where the relevant comments were.)