RFR (S) 8205608: Fix 'frames()' in ThreadReferenceImpl.c to prevent quadratic runtime behavior

[Chris Plummer]

Hi Ralf,

Overall looks good, but I do have a few comments and questions.

Please update the copyright.

What testing have you done?

How long does this test take to run.

What happens if for some reason SOE is never thrown? It's not clear to 
me what the script would do in this case.

In answer to the ShellScaffold.sh question, there is already work 
underway to convert to pure java tests. See JDK-8201652. I'm not certain 
if it is ok for you to just submit this new shell script, or if should 
be rewritten in pure java. Most of the work to convert the scripts has 
already been done but was put on hold. Maybe Serguei can comment and 
guide you on how it would be done in java.

thanks,

Chris

On 7/3/18 3:43 AM, Schmelter, Ralf wrote:
> Hi All,
>
> Please review the fix for the bughttps://bugs.openjdk.java.net/browse/JDK-8205608  . The webref is athttp://cr.openjdk.java.net/~simonis/webrevs/2018/8205608/  .
>
> This fixes the quadratic runtime (in the number of frames) of the frames() method, making it linear instead. It uses additional memory proportional to the number of frames on the stack.
>
> I've included a jtreg test, which would time out in the old implementation (since it takes minutes to get the stack frames). I'm not sure how useful this is.
>
> Best regards,
> Ralf Schmelter