Re: [Sablevm-developer] Question about _svmf_stopping_java()

[Etienne G. <gag...@uq...>]

Archie Cobbs wrote:
> The reasoning is simple: pending_halt_thread_count only counts threads
> that are running in Java mode. When it reaches zero, you consider the
> world halted, yet there may very well be threads running in native mode
> that had already entered native mode when stop_the_world() was called
> (and so they didn't count in the pending_halt_thread_count total).

This is exacly what we want.  Do you have any idea when a native thread might
call back into the VM (e.g. either the call ends, or some JNI function is called)?
I don't.  In fact, the native thread might be sleeping or into some kind of
almost infinite loop.  We definitely don't want GC to wait for such thread.

> So if that's the case, then my idea of allowing halting threads to enter
> native mode should not be adding any bugs that aren't already there.
> Am I making any sense? :-)

Yes and no.  We would have to change the state diagram and
make sure we have not introduced a bug somewhere else.

In the state diagram, there is no direct transition from SVM_THREAD_STATUS_HALT_REQUESTED
to SVM_THREAD_STATUS_NOT_RUNNING_JAVA_RESUMING_DISALLOWED.

OK.  This is all hypothetical stuff.  Let stop it here.

Etienne
PS:  Of course, it would be awesome if somebody gave his notes to Chris for
transcription. :-)  Thanks for the offer, Chris.

-- 
Etienne M. Gagnon, Ph.D.             http://www.info.uqam.ca/~egagnon/
SableVM:                                       http://www.sablevm.org/
SableCC:                                       http://www.sablecc.org/