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

[tstuefe]

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.

---

Progress

• Change must not contain extraneous whitespace
• Commit message must refer to an issue
• Change must be properly reviewed

Issue

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

Reviewers

• Lutz Schmidt (@RealLucy - Reviewer)

Download

$ git fetch https://git.openjdk.java.net/jdk pull/2686/head:pull/2686
$ git checkout pull/2686

[bridgekeeper]

👋 Welcome back stuefe! A progress list of the required criteria for merging this PR into master will be added to the body of your pull request. There are additional pull request commands available for use with this pull request.

[openjdk]

@tstuefe The following label will be automatically applied to this pull request:

• hotspot-runtime

When this pull request is ready to be reviewed, an "RFR" email will be sent to the corresponding mailing list. If you would like to change these labels, use the /label pull request command.

[mlbridge]

Webrevs

• 00: Full (9500117)

[y1yang0]

Looks good! IMHO, can we simply reorder these settings? i.e.

Settings:
AppCDS: on
Initial GC threshold: 20,75 MB
Current GC threshold: 21,50 MB
MaxMetaspaceSize: 17179869184,00 GB
MetaspaceReclaimPolicy: balanced
CompressedClassSpaceSize: 1,00 GB

[tstuefe]

Hi Yang,

Looks good! IMHO, can we simply reorder these settings? i.e.

Settings:
AppCDS: on
Initial GC threshold: 20,75 MB
Current GC threshold: 21,50 MB
MaxMetaspaceSize: 17179869184,00 GB
MetaspaceReclaimPolicy: balanced
CompressedClassSpaceSize: 1,00 GB

Sure, I can reorder that, but on what base? Alphabetically?

..Thomas

[y1yang0]

Maybe good-looking based ordering : )

[tstuefe]

Maybe good-looking based ordering : )

In that case I rather keep it as it is, since its ordered by subjective importance :)

[RealLucy]

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?

[RealLucy]

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.

[tstuefe]

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.

Thanks Lutz! Yes, I left the fix for MaxMetaspaceSize out to not interfere with Yi Yang's change.

Cheers, Thomas

[tstuefe]

/integrate

[openjdk]

@tstuefe This PR has not yet been marked as ready for integration.

[tstuefe]

@RealLucy Can you please approve then? Thanks!

[RealLucy]

With the other change: LGTM.

[tstuefe]

@RealLucy Can you please approve? As in, press the "Approve" button? :) Thanks!

[RealLucy]

LGTM.

[openjdk]

@tstuefe This change now passes all automated pre-integration checks.

ℹ️ This project also has non-automated pre-integration requirements. Please see the file CONTRIBUTING.md for details.

After integration, the commit message for the final commit will be:

8262163: Extend settings printout in jcmd VM.metaspace

Reviewed-by: lucy

You can use pull request commands such as /summary, /contributor and /issue to adjust it as needed.

At the time when this comment was updated there had been 27 new commits pushed to the master branch:

• 0f8be6e: 8261868: Reduce inclusion of metaspace.hpp
• 3a0d6a6: 8262099: jcmd VM.metaspace should report unlimited size if MaxMetaspaceSize isn't specified
• a50725d: 8254001: [Metrics] Enhance parsing of cgroup interface files for version detection
• 6549212: 8262315: missing ';' in generated entities
• d70fd7b: 8258855: Two tests sun/security/krb5/auto/ReplayCacheTestProc.java and ReplayCacheTestProcWithMD5.java failed on OL8.3
• 9d9ad96: 8261919: java/util/Locale/LocaleProvidersRun.java failed with "RuntimeException: Expected log was not emitted. LogRecord: null"
• 2c99bad: 8261920: [AIX] jshell command throws java.io.IOError on non English locales
• 8c07063: 8262259: Remove unused variable in MethodLiveness::BasicBlock::compute_gen_kill_single
• 0d2dbd2: 8262027: Improve how HttpConnection detects a closed channel when taking/returning a connection to the pool
• 382e38d: 8256438: AArch64: Implement match rules with ROR shift register value
• ... and 17 more: https://git.openjdk.java.net/jdk/compare/8cfea7c523fdda1375dc74bfc3a1042d45f2188e...master

As there are no conflicts, your changes will automatically be rebased on top of these commits when integrating. If you prefer to avoid this automatic rebasing, please check the documentation for the /integrate command for further details.

➡️ To integrate this PR with the above commit message to the master branch, type /integrate in a new comment.

[tstuefe]

/integrate

[openjdk]

@tstuefe Since your change was applied there have been 28 commits pushed to the master branch:

• a83e802: 8262299: C2 compilation fails with "modified node was not processed by IGVN.transform_old()"
• 0f8be6e: 8261868: Reduce inclusion of metaspace.hpp
• 3a0d6a6: 8262099: jcmd VM.metaspace should report unlimited size if MaxMetaspaceSize isn't specified
• a50725d: 8254001: [Metrics] Enhance parsing of cgroup interface files for version detection
• 6549212: 8262315: missing ';' in generated entities
• d70fd7b: 8258855: Two tests sun/security/krb5/auto/ReplayCacheTestProc.java and ReplayCacheTestProcWithMD5.java failed on OL8.3
• 9d9ad96: 8261919: java/util/Locale/LocaleProvidersRun.java failed with "RuntimeException: Expected log was not emitted. LogRecord: null"
• 2c99bad: 8261920: [AIX] jshell command throws java.io.IOError on non English locales
• 8c07063: 8262259: Remove unused variable in MethodLiveness::BasicBlock::compute_gen_kill_single
• 0d2dbd2: 8262027: Improve how HttpConnection detects a closed channel when taking/returning a connection to the pool
• ... and 18 more: https://git.openjdk.java.net/jdk/compare/8cfea7c523fdda1375dc74bfc3a1042d45f2188e...master

Your commit was automatically rebased without conflicts.

Pushed as commit ea48a0b.

💡 You may see a message that your pull request was closed with unmerged commits. This can be safely ignored.