RFR: 8373945: vmTestbase eatMemory/ClassUnloader provoke OOME to force GC and might cause GC in other threads

[SendaoYan]

On Thu, 18 Dec 2025 08:26:44 GMT, SendaoYan <syan at openjdk.org> wrote:

> Hi all,
> 
> This PR use `WhiteBox.getWhiteBox().fullGC()` instead of `eatMemory` to grigger full GC. The OOME trigger by `eatMemory` may cause vmTestbase/nsk/monitoring/stress/classload tests intermittent fails when run those tests simultancely on some machines. The WB.fullGC() might be use for same purpose. It also reduce test execution time.
> 
> Change has been verified locally by running tests vmTestbase/nsk/monitoring/stress/classload on linux-x64.
> 
> Additional testing:
> 
> - [ ] All jtreg tests by fastdebug build

GHA report jdk build fails on linux-x64-hs-optimized. Seems like environmental issue or infrastructure issue. It's unrelated to this PR.

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PR Comment: https://git.openjdk.org/jdk/pull/28891#issuecomment-3669059576