RFR: JDK-8262163: Extend settings printout in jcmd VM.metaspace

[Lutz Schmidt]

On Wed, 24 Feb 2021 17:11:20 GMT, Lutz Schmidt <lucy at openjdk.org> wrote:

>> This is quite trivial. 
>> 
>> jcmd VM.metaspace prints metaspace settings at the end of its printout. Missing from that printout are some settings which would be nice to see here, eg the GC thresholds and CDS settings (nice to know since CDS affects how metaspace is used).
>> 
>> Example output:
>> 
>> Settings:
>> MaxMetaspaceSize: 17179869184,00 GB
>> CompressedClassSpaceSize: 1,00 GB
>> Initial GC threshold: 20,75 MB
>> Current GC threshold: 21,50 MB
>> CDS: on
>> MetaspaceReclaimPolicy: balanced
>> -------
>> Tests: Manually ran runtime/Metaspace/PrintMetaspaceDcmd.java.
>
> The changes look good to me. 
> 
> What I don't like is the printout of the MaxMetaspaceSize value. It is outrageously big. The value displayed corresponds to 0x400000000 GB. Looking at the code, I would expect "unlimited" to be printed. Can you explain why it is not?

I just found JDK-8262099. It deals with the effect I disliked in my review comment. So, once JDK-8262099 is in, I am happy with this change here.

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PR: https://git.openjdk.java.net/jdk/pull/2686