RFR: 8235366: ZGC: Kitchensink.java fails in ZBarrier::should_mark_through

[Per Liden]

Thanks Stefan.

/Per

On 12/10/19 10:04 AM, Stefan Karlsson wrote:
> Looks good.
> 
> StefanK
> 
> On 2019-12-09 11:57, Per Liden wrote:
>> JDK-8230661 introduced a bug where we can accidentally "downgrade" an 
>> oop while healing it. More specifically, during the marking phase, an 
>> AS_NO_KEELALIVE load racing with finalizable marking could leave the 
>> oop in a remapped state (instead of finalizable marked state).
>>
>> The problem is the conditions for when to re-try a failing heal CAS. 
>> Instead of using an is_good_or_null() check, this patch uses the 
>> barrier fast_path() in the self_heal() function to avoid "downgrading" 
>> oops.
>>
>> Bug: https://bugs.openjdk.java.net/browse/JDK-8235366
>> Webrev: http://cr.openjdk.java.net/~pliden/8235366/webrev.1
>>
>> Testing: ZGC tier1-8
>>
>> /Per