CSR Review: 8189423: Add option to disable stack overflow checking in primordial thread for use with JNI_CreateJavaJVM

[Robbin Ehn]

Hi,

On 10/17/2017 10:04 AM, Thomas Stüfe wrote:
> Hi David,
> 
> Just some notes:
> 
> - I am confused about the "primordial thread" naming; I always understood
> the primordial thread to be the thread running main(), not the thread
> invoking JNI_CreateJavaVM. I always used this term in this way for AIX
> related problems. How about "VM-Initializing thread"?

That is how I also have interpret it.

> 
> - Would this not also be a useful feature for other threads attached to the
> VM (AttachCurrentThread), as those threads may use a different SO-handling
> scheme too ?

This is much bigger problem imho. In a product I work with we had several different stack-sizes on attached threads.
E.g. a 3rd party library might have created a thread which you want to attach for a jni call.

> 
> Other than that, I think this is a useful addition. Would have helped me
> before on AIX (see https://bugs.openjdk.java.net/browse/JDK-8179327)

Since we had similar problems, we used the advice do not call CreateJavaVM with a thread you care about.
Just spawn a new thread and call CreateJavaVM, not sure if that is worth having an option for?

I much rather have an option that say do not try to figure out stacksize, because you can't.
Alternative you should have the option of attaching individual threads with different stacksizes.

It's also very confusing when you are using a 3rd party library which require large stacks.
A normal unix user would just set ulimit -s 32768, but you would also need to set Xss to 32M.
A not set Xss should be the same value as pthread create uses.

So my opinion is that R can fix this with a new thread for CreateJavaVM (temporarily) and we should spend some time figuring all this out before adding a new option?

Thanks Robbin

> 
> Kind Regards, Thomas
> 
> 
> 
> On Tue, Oct 17, 2017 at 9:22 AM, David Holmes <david.holmes at oracle.com>
> wrote:
> 
>> CSR: https://bugs.openjdk.java.net/browse/JDK-8189423
>>
>> Bug: https://bugs.openjdk.java.net/browse/JDK-8189170
>>
>> Could I please have a reviewer for this CSR request so I can fast-track it.
>>
>> Comments on the proposal are of course welcome.
>>
>> Thanks,
>> David
>>