RFR: 8370732: vmTestbase/nsk/jvmti/AttachOnDemand/attach020/TestDescription.java intermittent fails [v7]

[Leonid Mesnik]

On Wed, 29 Oct 2025 06:17:19 GMT, SendaoYan <syan at openjdk.org> wrote:

>> Hi all,
>> 
>> We observed the test vmTestbase/nsk/jvmti/AttachOnDemand/attach020/TestDescription.java intermittent fails. since the target application intermittent OOM. The target application will try to exhaust the heap memory and then trigger garbage collection by `ClassUnloader.eatMemory()` in file test/hotspot/jtreg/vmTestbase/nsk/jvmti/AttachOnDemand/attach020/attach020Target.java.
>> 
>> So I think it's better to limited the max heap usage of target application. Before this PR, the physical memory usage is about 30.7GB(this depends the total free memory on the test machine), and the jtreg main action take about 11 seconds to finish; After this PR, the physical memory usage is about 126MB, and the jtreg main action take about 0.7 senonds to finish. I use below command to get the usage of physical memory.
>> 
>> Change has been verified locally, test-fix only, no risk.
>> 
>> 
>> grep VmRSS /proc/`ps -ef | grep -w java | grep vmsqe.aod.AppId | awk '{print $2}'`/status
>
> SendaoYan has updated the pull request incrementally with one additional commit since the last revision:
> 
>   Remove unnecessary try/catch and loop

Sorry, I missed first time. See my comment about `import nsk.share.ClassUnloader;` inline.

test/hotspot/jtreg/vmTestbase/nsk/jvmti/AttachOnDemand/attach022/attach022Target.java line 51:

> 49: 
> 50:             log.display("Provoking GC");
> 51:             WhiteBox.getWhiteBox().fullGC();

Please also remove lines
`import nsk.share.ClassUnloader;`
ssince this class is not using anymore.

-------------

Changes requested by lmesnik (Reviewer).

PR Review: https://git.openjdk.org/jdk/pull/28011#pullrequestreview-3397245800
PR Review Comment: https://git.openjdk.org/jdk/pull/28011#discussion_r2476258933