On Wed, 29 Oct 2025 02:56:44 GMT, SendaoYan <[email protected]> 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:
>
> Add -Xmx128 for attach021/022
I think it would be better to use
WhiteBox.fullGC()
It is the fast and robust way to trigger Full GC without risks hitting OOME.
The test has been developed before WhiteBox was added.
-------------
PR Comment: https://git.openjdk.org/jdk/pull/28011#issuecomment-3459437370
