8268458: Add verification type for evacuation failures

[tschatzl]

Hi all,

can I have reviews for this change that adds a new verification type (argument for -XX:VerifyGCType for G1) that only enables verification after an evacuation failure?

The reasons is that time and time again we have issues with evacuation failure as it's by far not tested as much as regular collection, and reproducing issues then is often hampered by that there is no way to just verify after verification failure. Enabling it just for all young collections is possible, but typically does not help much.

Fwiw, this change requires a small semantics change in how the current VerifyGCType is compared to the one stored as active (i.e. in G1HeapVerifier::_enabled_verification_types). Since the situations that can be enabled are not distinct any more (any young gc can have an evacuation failure), the existing check for a given set bit in G1HeapVerifier::should_verify() does not work any more.

This also means that the previous assumption that G1VerifyType::G1VerifyAll is not the same as all flags enabled can not be checked any more. I do not think this is any loss in functionality (see the gtests for removed checks).

The same functionality could also have been implemented by injecting all of the young gen type bits into the existing type on evacuation failure at the cost of remembering that the user selected evacuation failures for evacuation somewhere else. Not sure if that would be simpler.

Testing: tier1-2 (still running), updated test

Thanks,
Thomas

---

Progress

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Issue

• JDK-8268458: Add verification type for evacuation failures

Reviewers

• Kim Barrett (@kimbarrett - Reviewer)
• Ivan Walulya (@walulyai - Committer)

Reviewing

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[openjdk]

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[tschatzl]

This change helped a lot with JDK-8267073.

[mlbridge]

Webrevs

• 00: Full (b03fe649)

[kimbarrett]

Looks good.

G1VerifyType seems poorly named. The name suggests a single value, but it's really a selection bitmask. Perhaps a followup RFE?

[openjdk]

@tschatzl 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:

8268458: Add verification type for evacuation failures

Reviewed-by: kbarrett, iwalulya

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 115 new commits pushed to the master branch:

• 1692fd2: 8017163: G1: Refactor remembered sets
• 0b8a0e2: 8266082: AssertionError in Annotate.fromAnnotations with -Xdoclint
• b7d78a5: Merge
• b8f073b: 8268316: Typo in JFR jdk.Deserialization event
• b9d7337: 8268638: semaphores of AsyncLogWriter may be broken when JVM is exiting.
• 8caeca0: 8264775: ClhsdbFindPC still fails with java.lang.RuntimeException: 'In java stack' missing from stdout/stderr
• 7e03cf2: 8265073: XML transformation and indentation when using xml:space
• 60389ee: 8269025: jsig/Testjsig.java doesn't check exit code
• dab00ee: 8266518: Refactor and expand scatter/gather tests
• f9c8c1c: 8268903: JFR: RecordingStream::dump is missing @SInCE
• ... and 105 more: https://git.openjdk.java.net/jdk/compare/94d0b0f9810bd1a8da06ec267a1c7589d6cb756b...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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[tschatzl]

Thanks @kimbarrett for your review. I agree that we should probably rename that flag, I'll file an RFE

[tschatzl]

Thanks @kimbarrett @walulyai for your reviews.

Integrate

[tschatzl]

/integrate

[openjdk]

Going to push as commit cd20c01.
Since your change was applied there have been 117 commits pushed to the master branch:

• a58c477: 8268952: Automatically update heap sizes in G1MonitoringScope
• cbec37d: 8269029: compiler/codegen/TestCharVect2.java fails for client VMs
• 1692fd2: 8017163: G1: Refactor remembered sets
• 0b8a0e2: 8266082: AssertionError in Annotate.fromAnnotations with -Xdoclint
• b7d78a5: Merge
• b8f073b: 8268316: Typo in JFR jdk.Deserialization event
• b9d7337: 8268638: semaphores of AsyncLogWriter may be broken when JVM is exiting.
• 8caeca0: 8264775: ClhsdbFindPC still fails with java.lang.RuntimeException: 'In java stack' missing from stdout/stderr
• 7e03cf2: 8265073: XML transformation and indentation when using xml:space
• 60389ee: 8269025: jsig/Testjsig.java doesn't check exit code
• ... and 107 more: https://git.openjdk.java.net/jdk/compare/94d0b0f9810bd1a8da06ec267a1c7589d6cb756b...master

Your commit was automatically rebased without conflicts.

[openjdk]

@tschatzl Pushed as commit cd20c01.

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