JVM hanging when using G1GC on JDK8 b78 or b79 (Linux 32 bit)

Thomas Schatzl thomas.schatzl at oracle.com
Wed Mar 6 05:43:04 PST 2013


Hi,

On Wed, 2013-03-06 at 13:49 +0100, Uwe Schindler wrote:
> Hi Bengt,
> 
> That was fast! We are happy that you were able to analyze the bug and will fix it soon. To not make our Jenkins server get stuck in the tests, I will disable G1GC until a new update is installed. We will then only test the other garbage collectors with Lucene.
> 
> Do you have an idea, why this bug is not appearing on 64 bit? It might be caused by other GC behavior as the word size is different (the Lucene tests use -Xmx512M, so its fixed in 32 and 64 bit at the moment). I just want to understand this! I can run the test suite with 64 bit JDK over and over, it never hangs. But when running with 32 bit it hangs in all cases.

  one possible reason is that the default mark stack size much is larger
on 64 bit, so no mark stack overflow occurs.

E.g. in globals.hpp:

  product(uintx, MarkStackSizeMax, NOT_LP64(4*M) LP64_ONLY(512*M),
\

You may want to try to set MarkStackSizeMax to 4M on 64 bit too to test
this.

This is just a hunch though.

Thomas




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