RFR(S): 8227225: ParallelGC: add subspace transitions for young gen for gc+heap=info log lines

[Thomas Schatzl]

Hi,

On Fri, 2019-07-19 at 10:40 -0700, Tony Printezis wrote:
> Hey Thomas,
> 
> Thanks for taking a look and again apologies for the late reply, I
> was on vacation until earlier this week. Please see inline.
> 
> [...]
> > > I have a similar change ready to go for GenCollectedHeap (Serial 
> > > / CMS). 
> > > I’ll see what the feedback is on this before I open that for 
> > > code review. 
> > > 
> > > A couple of notes: 
> > > 
> > > - I moved the PreGCValues class to gc/shared as I’d like to re-
> > > use  it for the GenCollectedHeap changes too.  
> > 
> > It's a bit awkwards as there are non-generational GCs now, but I do
> > not have a better idea. Maybe somebody else has. 
> 
> I could just rename this to GenPreGCValues so it’s clear it’s only
> for the generational GCs? Or I could come up with a convoluted class
> hierarchy that can handle both generational and non-generational GCs.
> But I’d rather not, given we don’t have any use cases for this for
> the latter. So, maybe, rename PreGCValues to GenPreGCValues and, if
> we need to in the future, we can just split the class as needed?

I agree with your plan. Don't do too much potentially unnecessary work
:)

Thanks,
  Thomas