RFR 8085965: VM hangs in C2Compiler

[Kim Barrett]

On Jun 16, 2015, at 1:59 PM, Jon Masamitsu <jon.masamitsu at oracle.com> wrote:
> 
> Poonam,
> 
> With your changes try
> 
> java -XX:+ExplicitGCInvokesConcurrentAndUnloadsClasses -XX:-ClassUnloading -XX:+UseConcMarkSweepGC  -XX:+PrintFlagsFinal -version
> 
> and check if ExplicitGCInvokesConcurrent is true or false.
> 
> If it is true, I don't know if that is the right thing to do.  In this case on the
> command line ExplicitGCInvokesConcurrentAndUnloadsClasses has been
> set to true and ClassUnloading has been set to false.  As a side effect,
> ExplicitGCInvokesConcurrent is set to true.  Whereas ExplicitGCInvokesConcurrentAndUnloadsClasses
> has been set back to false (probably) That may be a surprise to the
> users.

Yes, I think that would be a surprise.  That would be another reason to check for FLAG_IS_CMDLINE
and value is true for at least that one, and complain in some way if so.