RFR (S) 8135152: Create a G1ParScanThreadStateSet class for managing G1 GC per thread states

[Erik Helin]

On 2015-09-08, Mikael Gerdin wrote:
> All,
> 
> On 2015-09-07 17:08, Mikael Gerdin wrote:
> >Hi all,
> >
> >I'd like to move management of the G1ParScanThreadState instances into a
> >ParScanThreadStateSet class, similar to how ParNew works.
> >
> >This first change simply moves the code for allocation/deallocation
> >and flushing of stats from the par scan thread state to the state set
> >object.
> >
> >There is another change coming (8135154) where some additional stats and
> >counters are moved from other ad-hoc locations to the par scan thread
> >state set.
> >
> >Webrev: http://cr.openjdk.java.net/~mgerdin/8135152/webrev.0/
> 
> I got some feedback that moving all the flushing code to the pss set was not
> particularly pretty, I agree with that statement and I've created a flush
> method on the per thread state which is then called from the pss set flush
> method to make the flushing process more explicit.
> 
> Incremental webrev:
> http://cr.openjdk.java.net/~mgerdin/8135152/webrev.0_to_1/
> Full webrev: http://cr.openjdk.java.net/~mgerdin/8135152/webrev.1/

Thanks for doing this, the patch looks good, just one minor nit:
Expressions such as
  G1ParScanThreadState* pss = _pss->state_for_worker(worker_id);
are a bit confusing given that `_pss` represents multiple
G1ParScanThreadState's and `pss` is a single G1ParScanThreadState.
Maybe we should use a different name for _pss?

I'm fine with cleaning up this in a follow-up patch. Reviewed.

Thanks,
Erik

> /Mikael
> 
> 
> >Bug: https://bugs.openjdk.java.net/browse/JDK-8135152
> >
> >Testing: JPRT
> >
> >/Mikael
>