RFR 8251118: BiasedLocking::preserve_marks should not have a HandleMark

[Harold Seigel]

Hi Patricio,

The fix looks good.  Could you also add a test based on the failure 
discussed in the bug description?

Thanks, Harold

On 8/11/2020 2:11 PM, Patricio Chilano wrote:
> Hi all,
>
> Please review the following small fix which involves removing the 
> added HandleMark in BiasedLocking::preserve_marks():
>
> Bug: https://bugs.openjdk.java.net/browse/JDK-8251118
> Webrev: http://cr.openjdk.java.net/~pchilanomate/8251118/v1/webrev/
>
> I've inspected the callers of BiasedLocking::preserve_marks() and they 
> all have an assert that the current thread is the VMThread. Since the 
> VMThread creates a HandleMark object before executing a VM operation 
> the extra HandleMark added in 8249192 is not needed.
> I've run tiers1-3 in mach5 with -XX:+UseBiasedLocking and without the 
> patch I get several crashes in BiasedLocking::restore_marks(). With 
> the patch tests completed successfully.
>
> Thanks,
> Patricio
>