RFR: 8313395: LotsUnloadTest.java fails with OOME transiently with libgraal

[Ioi Lam]

On Thu, 10 Jul 2025 09:38:56 GMT, Doug Simon <dnsimon at openjdk.org> wrote:

> Is the increased memory usage of Graal limited to `-Xcomp` runs?

Yes. Here are the logs from my comments in the bug report. Memory use goes from about 32m to about 96m when -Xcomp is used with graal.


$ java -Xmx64m -Xms32m -Xcomp -cp . LotsUnloadApp
$ java -Xmx64m -Xms32m -Xcomp -XX:+UnlockExperimentalVMOptions -XX:+EnableJVMCI -cp . LotsUnloadApp
$ java -Xmx64m -Xms32m -Xcomp -XX:+UnlockExperimentalVMOptions -XX:+UseGraalJIT -cp . LotsUnloadApp

Exception: java.lang.OutOfMemoryError thrown from the UncaughtExceptionHandler in thread "Thread-3"
Exception in thread "Thread-2" java.lang.OutOfMemoryError: Java heap space
java.lang.OutOfMemoryError: Java heap space
Exception in thread "Thread-0" java.lang.OutOfMemoryError: Java heap space

$ java -Xmx96m -Xms32m -Xcomp -XX:+UnlockExperimentalVMOptions -XX:+UseGraalJIT -cp . LotsUnloadApp
$

$ java -Xmx48m -Xms32m -Xcomp -cp . LotsUnloadApp
$ java -Xmx32m -Xms32m -Xcomp -cp . LotsUnloadApp
$ java -Xmx32m -Xms32m -XX:+UnlockExperimentalVMOptions -XX:+UseGraalJIT -cp . LotsUnloadApp
$

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

PR Comment: https://git.openjdk.org/jdk/pull/26230#issuecomment-3057974643