[8u] RFR: 8250627: Use -XX:+/-UseContainerSupport for enabling/disabling Java container metrics

[Severin Gehwolf]

On Tue, 2020-08-04 at 18:21 +0200, Aleksey Shipilev wrote:
> On 8/4/20 5:49 PM, Severin Gehwolf wrote:
> > Bug: https://bugs.openjdk.java.net/browse/JDK-8250627
> > webrev: https://cr.openjdk.java.net/~sgehwolf/webrevs/JDK-8250627/jdk8/01/
> > JDK 11 change: https://hg.openjdk.java.net/jdk-updates/jdk11u-dev/rev/a75956082916
> 
> Substantially, I think the patch is fine.

Thanks for the review!

> But, I do wonder if the new classes should be in sun.misc.*, not in jdk.internal.*. One of the
> reasons to use sun.misc.* is to get the proper javac warning on use. jdk.internal is something that
> is protected by module boundaries in JDK 9+, not available in 8u.

That's a good point. However, we should discuss this in context of JDK-
8203357 which actually introduces the Java metrics classes. This patch,
then should follow suite.

With that being said, I'm not sure diverging from later JDKs for that
reason is warranted. Another data point is JFR java classes which also
seem to partially under jdk.jfr.internal in JDK 8u. Just like JDK 11u.

Thanks,
Severin