8277946: NMT: Deprecate and remove VM.native_memory shutdown jcmd command option

[zhengyu123]

NMT shutdown functionality is a remnant of its first implementation, which could consume excessive amount of memory, therefore, it needed capability to shut it self down to ensure health of JVM. This is no longer a case for new implementation.

NMT shutdown can be requested via Jcmd. However, it is rare used.

We should deprecate for shutdown Jcmd command for removing NMT shutdown functionality.

Corresponding CSR has been approved.

---

Progress

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Issues

• JDK-8277946: NMT: Deprecate and remove VM.native_memory shutdown jcmd command option
• JDK-8277947: NMT: Deprecate and remove VM.native_memory shutdown jcmd command option (CSR) ⚠️ Issue is not open.

Reviewers

• Thomas Stuefe (@tstuefe - Reviewer)
• Aleksey Shipilev (@shipilev - Reviewer)
• David Holmes (@dholmes-ora - Reviewer)

Reviewing

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[mlbridge]

Webrevs

• 00: Full (69e0d17b)

[tstuefe]

Nice. Looks good. But that just removes the jcmd; I assume you remove the shutdown-on-OOM functionality, together with shutdown mechanics itself, in a separate RFE?

[openjdk]

@zhengyu123 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:

8277946: NMT: Deprecate and remove VM.native_memory shutdown jcmd command option

Reviewed-by: stuefe, shade, dholmes

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:

• da2be99: 8277026: Remove blank lines remaining from snippet markup
• 0a01baa: 8277986: Typo in javadoc of java.util.zip.ZipEntry#setTime
• 7049c13: 8231107: Allow store password to be null when saving a PKCS12 KeyStore
• ab867f6: 8272162: S4U2Self ticket without forwardable flag
• dd73e3c: 8277814: ConcurrentRefineThread should report rate when deactivating
• 65251f7: 8151594: Move concurrent refinement thread activation logging out of GC pause
• f1c20e9: 8190748: java/text/Format/DateFormat/DateFormatTest.java and NonGregorianFormatTest fail intermittently
• 2942646: 8276683: Malformed Javadoc inline tags in JDK source in com/sun/tools/javac/util/RawDiagnosticFormatter.java
• e30e676: 8277606: String(String) constructor could copy hashIsZero
• 5a4a9bb: 8278019: ProblemList java/awt/dnd/BadSerializationTest/BadSerializationTest.java on linux and windows
• ... and 17 more: https://git.openjdk.java.net/jdk/compare/05ab1767684bee0a3b8c8214c610beafaad058f9...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.

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[zhengyu123]

Nice. Looks good. But that just removes the jcmd; I assume you remove the shutdown-on-OOM functionality, together with shutdown mechanics itself, in a separate RFE?

Thanks for the review, @tstuefe

Yes, I filed JDK-8277990 to remove the rest.

[shipilev]

Looks fine. I wonder: was NMT_minimal the state after "shutdown"? If so, should it be removed too? (in separate PR, probably)

[zhengyu123]

Looks fine. I wonder: was NMT_minimal the state after "shutdown"? If so, should it be removed too? (in separate PR, probably)

Thanks for the review, @shipilev

Yes, NMT_minimal will be removed in followup CR 8277990.

[dholmes-ora]

Hi Zhengyu,

I am fine with removal of the shutdown option of the jcmd as presented, but as per the CSR request I think "Deprecate" has to be removed from this as nothing has been deprecated.

I'm not at all clear why the actual shutdown mechanics removal has been deferred to another issue - that would make sense if this PR actually just deprecated something, but as it is I would have expected everything to go. With RDP1 upon us I assume the actual removal will now be in 19.

Thanks,
David

[zhengyu123]

Hi Zhengyu,

I am fine with removal of the shutdown option of the jcmd as presented, but as per the CSR request I think "Deprecate" has to be removed from this as nothing has been deprecated.

I'm not at all clear why the actual shutdown mechanics removal has been deferred to another issue - that would make sense if this PR actually just deprecated something, but as it is I would have expected everything to go. With RDP1 upon us I assume the actual removal will now be in 19.

Thanks, David

Hi David,

Thanks for the review. I were not sure I should remove shutdown mechanics with this CR, as it only mentions jcmd part and there is auto-shutdown part also.

I already have the second change ready, will PR tomorrow, it is quite large through.

-Zhengyu

[zhengyu123]

/integrate

[openjdk]

Going to push as commit abaa073.
Since your change was applied there have been 37 commits pushed to the master branch:

• 37ff7f3: 8277866: gc/epsilon/TestMemoryMXBeans.java failed with wrong initial heap size
• 8d7958e: 8277981: String Deduplication table is never cleaned up due to bad dead_factor_for_cleanup
• bc6dce1: 8277736: G1: Allow forced evacuation failure of first N regions in collection set
• 0c29ee5: 8274319: Replace usages of Collections.sort with List.sort call in jdk.jfr
• f505396: 8277459: Add jwebserver tool
• 84aa0a1: 8278047: Few javax/imageio test regressed after JDK-8262297 fix
• fde0b95: 8277861: Terminally deprecate Thread.stop
• 70d5dff: 8275326: C2: assert(no_dead_loop) failed: dead loop detected
• 349328c: 8277777: [Vector API] assert(r->is_XMMRegister()) failed: must be in x86_32.ad
• c733193: 8262297: ImageIO.write() method will throw IndexOutOfBoundsException
• ... and 27 more: https://git.openjdk.java.net/jdk/compare/05ab1767684bee0a3b8c8214c610beafaad058f9...master

Your commit was automatically rebased without conflicts.

[openjdk]

@zhengyu123 Pushed as commit abaa073.

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