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8277919: OldObjectSample event causing bloat in the class constant pool in JFR recording #15

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@mgronlun mgronlun commented Dec 13, 2021

Greetings,

Allocation heavy applications with OldObjectSample with stacktraces enabled will end up storing many duplicates of the same klass artefact, creating a considerable bloat in the class area of the recording constant pool. This is because of JDK-8233705, which can lead to multiple klass entries enqueued via the load barrier, in combination with an insufficient filter mechanism for the leak profiler artefacts. Leak profiler artefacts range over the entire set of artefacts enqueued in the previous epoch. Careful selection of clearing leakp bits for classes becomes a sufficient filtering mechanism similar to the one used for regular artefacts to avoid duplicates.

Thanks to @jbachorik for reporting and doing the initial analysis.

Markus


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  • JDK-8277919: OldObjectSample event causing bloat in the class constant pool in JFR recording

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bridgekeeper bot commented Dec 13, 2021

👋 Welcome back mgronlun! 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 openjdk bot added the rfr Pull request is ready for review label Dec 13, 2021
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openjdk bot commented Dec 13, 2021

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

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mlbridge bot commented Dec 13, 2021

Webrevs

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openjdk bot commented Dec 14, 2021

@mgronlun 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:

8277919: OldObjectSample event causing bloat in the class constant pool in JFR recording

Reviewed-by: jbachorik

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At the time when this comment was updated there had been 2 new commits pushed to the master branch:

  • 32139c1: 8262134: compiler/uncommontrap/TestDeoptOOM.java failed with "guarantee(false) failed: wrong number of expression stack elements during deopt"
  • c93b24d: 8132785: java/lang/management/ThreadMXBean/ThreadLists.java fails intermittently

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@openjdk openjdk bot added the ready Pull request is ready to be integrated label Dec 14, 2021
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mgronlun commented Dec 14, 2021

/integrate

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openjdk bot commented Dec 14, 2021

Going to push as commit 475ec8e.
Since your change was applied there have been 2 commits pushed to the master branch:

  • 32139c1: 8262134: compiler/uncommontrap/TestDeoptOOM.java failed with "guarantee(false) failed: wrong number of expression stack elements during deopt"
  • c93b24d: 8132785: java/lang/management/ThreadMXBean/ThreadLists.java fails intermittently

Your commit was automatically rebased without conflicts.

@openjdk openjdk bot closed this Dec 14, 2021
@openjdk openjdk bot added integrated Pull request has been integrated and removed ready Pull request is ready to be integrated rfr Pull request is ready for review labels Dec 14, 2021
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openjdk bot commented Dec 14, 2021

@mgronlun Pushed as commit 475ec8e.

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

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@jbachorik Unknown command backport - for a list of valid commands use /help.

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