RFR: Backport 8195115: G1 Old Gen MemoryPool CollectionUsage.used values don't reflect mixed GC results

[Thomas Schatzl]

Hi Paul,

On Fri, 2018-10-12 at 00:03 +0000, Hohensee, Paul wrote:
> Please review a backport to jdk8u.
> 
> Bug: https://bugs.openjdk.java.net/browse/JDK-8195115
> Webrev: http://cr.openjdk.java.net/~phh/8195115/webrev.05/
> JDK11 patch: http://hg.openjdk.java.net/jdk/jdk/rev/5d3c5af82654
> 
> The backport is slightly different from the JDK11 patch due to G1
> refactoring, hence my request for new review. I’ll ask for jdk8u
> approval once the backport is reviewed.

> I backported two jtreg tests from JDK11, which pass. Also, all the
> hotspot gc jtreg tests pass as well as they do for jdk8u-dev.

I think the backport is good. Others need to decide whether this change
is worth backporting.

> There was a CSR involved, 
> https://bugs.openjdk.java.net/browse/JDK-8196719. Does that have to
> be re-approved for jdk8u as well, and if so, what’s the process?

CC'ed Joe Darcy as I am not sure either.

Thanks,
  Thomas