RFR(s): 8198553: jcmd: separate Metaspace statistics from NMT

[coleen.phillimore at oracle.com]

Looks good, I'm happy to sponsor.
Coleen

On 2/22/18 8:41 AM, Thomas Stüfe wrote:
> Hi all,
>
> may I please have reviews and a sponsor for this small change:
>
> Issue: https://bugs.openjdk.java.net/browse/JDK-8198553
> webrev:
> http://cr.openjdk.java.net/~stuefe/webrevs/8198553-jcmd-separate-metaspace-stat-from-nmt/webrev.00/webrev/
>
> Prior discussion on hotspot-runtime:
> http://mail.openjdk.java.net/pipermail/hotspot-runtime-dev/2018-February/026354.html
> .
>
> This patch introduces a new jcmd command, "VM.metaspace", which prints out
> the metaspace statistics we before had as part of the NMT printout
> (VM.native_memory). This is better because we now can print metaspace
> statistics at any time regardless whether NMT is switched on or not.
>
> Note that this does not affect the Metaspace information printed as part of
> the final NMT report (-XX:+PrintNMTStatistics). That is still there.
>
> Tested on Windows, AIX and Linux x64.
>
> Thanks, Thomas