RFR: 8221359: Eliminate SATBMarkQueueSet::filter_thread_buffers

[Thomas Schatzl]

Hi Kim,

On Mon, 2019-04-01 at 03:40 -0400, Kim Barrett wrote:
> Please review this removal of the function used by G1 to clean up the
> per-thread SATB queues when a young-only collection will have moved
> young object references present in those queues.  This cleanup isn't
> needed, since the same cleanup may be done before enqueuing a
> completed queue buffer, and will also be done during the eventual
> processing of the buffer contents.  Having this function called
> during
> a pause just moves some work from the concurrent phase into a pause,
> which isn't a good tradeoff.
> 
> Also renamed G1GCPhaseTimes::ExtRootScanSubPhases(Start|End) =>
> ExtRootScanSubPhases(First|Last), to remove the ambiguity over
> whether
> "end" is inclusive or exclusive.  (It was inclusive here.)
> 
> CR:
> https://bugs.openjdk.java.net/browse/JDK-8221359
> 
> Webrev:
> http://cr.openjdk.java.net/~kbarrett/8221359/open.00/
> 

  looks good.

Thanks,
  Thomas