8362482: [TESTBUG] serviceability/HeapDump/UnmountedVThreadNativeMethodAtTop.java: System.gc() does not provide full GC

[reinrich]

Call WhiteBox.fullGC() instead of System.gc() for a guaranteed full GC.
It is assumed that one full GC is sufficient for these tests.

Testing was done with fastdebug and release builds on the main platforms and also on Linux/PPC64le and AIX.

---

Progress

• Change must be properly reviewed (1 review required, with at least 1 Reviewer)
• Change must not contain extraneous whitespace
• Commit message must refer to an issue

Issue

• JDK-8362482: [TESTBUG] serviceability/HeapDump/UnmountedVThreadNativeMethodAtTop.java: System.gc() does not provide full GC (Bug - P4)

Reviewers

• Serguei Spitsyn (@sspitsyn - Reviewer)
• Christoph Langer (@RealCLanger - Reviewer)

Reviewing

Using git

Checkout this PR locally:
$ git fetch https://git.openjdk.org/jdk.git pull/26363/head:pull/26363
$ git checkout pull/26363

Update a local copy of the PR:
$ git checkout pull/26363
$ git pull https://git.openjdk.org/jdk.git pull/26363/head

Using Skara CLI tools

Checkout this PR locally:
$ git pr checkout 26363

View PR using the GUI difftool:
$ git pr show -t 26363

Using diff file

Download this PR as a diff file:
https://git.openjdk.org/jdk/pull/26363.diff

Using Webrev

Link to Webrev Comment

[bridgekeeper]

👋 Welcome back rrich! 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]

@reinrich 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:

8362482: [TESTBUG] serviceability/HeapDump/UnmountedVThreadNativeMethodAtTop.java: System.gc() does not provide full GC

Reviewed-by: sspitsyn, clanger

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 49 new commits pushed to the master branch:

• 08b0b34: 8361715: (bf) Improve java/nio/Buffer/GetChars.java and migrate to JUnit
• 7bf4c60: 8364120: RISC-V: unify the usage of MacroAssembler::instruction_size
• b7703f7: 8364185: [BACKOUT] AArch64: [VectorAPI] sve vector math operations are not supported after JDK-8353217
• ... and 46 more: https://git.openjdk.org/jdk/compare/0735dc27c71de46896afd2f0f608319304a3d549...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.

[openjdk]

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

• serviceability

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.

[sendaoYan]

Maybe use '@run junit/othervm/native' more better.

[reinrich]

I guess that's better. Thanks for the hint. I wasn't aware of the /native option.

[openjdk]

@reinrich this pull request can not be integrated into master due to one or more merge conflicts. To resolve these merge conflicts and update this pull request you can run the following commands in the local repository for your personal fork:

git checkout 8362482_whitebox_fullgc
git fetch https://git.openjdk.org/jdk.git master
git merge FETCH_HEAD
# resolve conflicts and follow the instructions given by git merge
git commit -m "Merge master"
git push

[mlbridge]

Webrevs

• 00: Full (62353839)

[sspitsyn]

This looks good.

[reinrich]

Thanks!
/integrate

[openjdk]

Going to push as commit b4028c9.
Since your change was applied there have been 49 commits pushed to the master branch:

• 08b0b34: 8361715: (bf) Improve java/nio/Buffer/GetChars.java and migrate to JUnit
• 7bf4c60: 8364120: RISC-V: unify the usage of MacroAssembler::instruction_size
• b7703f7: 8364185: [BACKOUT] AArch64: [VectorAPI] sve vector math operations are not supported after JDK-8353217
• ... and 46 more: https://git.openjdk.org/jdk/compare/0735dc27c71de46896afd2f0f608319304a3d549...master

Your commit was automatically rebased without conflicts.

[openjdk]

@reinrich Pushed as commit b4028c9.

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

[reinrich]

/backport :jdk25

[openjdk]

@reinrich Could not automatically backport b4028c91 to openjdk/jdk due to conflicts in the following files:

• test/hotspot/jtreg/serviceability/HeapDump/UnmountedVThreadNativeMethodAtTop.java

Please fetch the appropriate branch/commit and manually resolve these conflicts by using the following commands in your personal fork of openjdk/jdk. Note: these commands are just some suggestions and you can use other equivalent commands you know.

# Fetch the up-to-date version of the target branch
$ git fetch --no-tags https://git.openjdk.org/jdk.git jdk25:jdk25

# Check out the target branch and create your own branch to backport
$ git checkout jdk25
$ git checkout -b backport-reinrich-b4028c91-jdk25

# Fetch the commit you want to backport
$ git fetch --no-tags https://git.openjdk.org/jdk.git b4028c91d5615f43cbf209eeeb1014966de22a38

# Backport the commit
$ git cherry-pick --no-commit b4028c91d5615f43cbf209eeeb1014966de22a38
# Resolve conflicts now

# Commit the files you have modified
$ git add files/with/resolved/conflicts
$ git commit -m 'Backport b4028c91d5615f43cbf209eeeb1014966de22a38'

Once you have resolved the conflicts as explained above continue with creating a pull request towards the openjdk/jdk with the title Backport b4028c91d5615f43cbf209eeeb1014966de22a38.

Below you can find a suggestion for the pull request body:

Hi all,

This pull request contains a backport of commit b4028c91 from the openjdk/jdk repository.

The commit being backported was authored by Richard Reingruber on 28 Jul 2025 and was reviewed by Serguei Spitsyn and Christoph Langer.

Thanks!