[8u] RFR: 8203357: Container Metrics

[Severin Gehwolf]

On Thu, 2020-07-30 at 11:17 +0200, Severin Gehwolf wrote:
> Hi Andrew,
> 
> Thanks for the review!
> 
> On Tue, 2020-07-21 at 20:38 +0100, Andrew Hughes wrote:
> > On 16/07/2020 16:48, Severin Gehwolf wrote:
> > > Hi,
> > > 
> > > Please review this OpenJDK 8u backport of the Java Metrics classes
> > > which are in later JDKs. It is a pre-requisite for JDK-8226575 an
> > > Oracle JDK parity issue. Implementations of the interface are provided
> > > for Linux only and, thus, are compiled for Linux only. This backport
> > > differs from the original JDK 11 change in the following way:
> > > 
> > >  * MetricsTester: Arrays.compare() => Arrays.equals(). Arrays.compare()
> > >    is JDK 9+ only.
> > >  * JDK-8223147: JFR Backport, brought in test library code included in
> > >    the JDK 11 changeset. I've only done the needed adjustments to the
> > >    relevant files in the test libary. Many were already present.
> > >  * For this backport I've not included changes to the Launcher to
> > >    support -XshowSettings:system (as in later JDKs).
> > > 
> > > Bug: https://bugs.openjdk.java.net/browse/JDK-8203357
> > > webrev: 
> > > http://cr.openjdk.java.net/~sgehwolf/webrevs/JDK-8203357/jdk8/01/webrev/
> > > 
> > > Testing: Included docker tests on Linux x86_64. All pass. Though, they
> > > are in dire need of reliability improvements which I'll work on as a
> > > follow-up.
> > > 
> > > Thanks,
> > > Severin
> > > 
> [...]
> > Comments:
> >   * @author tags are removed from Container.java & Metrics.java. Why? I
> > can see a case for removing the "@since 11" but not the authorship.
> >   * Removal of test code related to the module system seems fine.
> 
> [...]
> 
> > Comments:
> >   * The Makefile changes look right and in line with those for Mac OS & AIX.
> >   * The MetricsTester changes look correct. I can only imagine this
> > wasn't caught when the test was backported because JDK-8206456 was also
> > backported and so the length != 0 checks that introduced were never
> > triggered (as the metrics weren't actually there)
> 
> It appears MetricsTester was never run, thus compiled. So I think this
> never worked in 8u. Now code uses it and the Arrays.compare() JDK 9+
> feature needed to be reworked.
> 
> [...]
> 
> > So, action items are the missing @author tags and launcher support.
> 
> New webrev:
> http://cr.openjdk.java.net/~sgehwolf/webrevs/JDK-8203357/jdk8/02/webrev/
> 
> Thoughts?

Ping? This is blocking some other backports in my queue.

Thanks,
Severin