[8] RFR: Shenandoah: JNI weak roots are always cleared before Full GC mark

[Zhengyu Gu]

Hi Kornel,

Yes, I will RFR to backout this workaround.

Thanks,

-Zhengyu

On 8/28/20 12:52 AM, Kornel Pal wrote:
> Hi Aleksey,
> 
> Thank you very much for all the dedicated work on Shenandoah GC, it 
> really is useful.
> 
> I wonder whether this workaround could safely be removed, now that 
> JDK-8248041 was backported to 8u.
> 
> Thank you,
> Kornel
> 
> On 2020-06-22 19:39, Aleksey Shipilev wrote:
>> Amir found the crash with Cassandra that started to happen recently 
>> with Shenandoah 8u. It
>> reproduces more or less reliably with starting Cassandra 3.11.4 with 
>> fastdebug build and
>> -XX:ShenandoahGCMode=passive -XX:-ShenandoahDegeneratedGC.
>>
>> This is a symptom of a larger problem (see JDK-8248041), but 8u it is 
>> catastrophic due to clearing
>> of the weak roots.
>>
>> Fix:
>>    
>> https://cr.openjdk.java.net/~shade/shenandoah/8u-fullgc-jni-weak/webrev.01/ 
>>
>>
>> Testing: hotspot_gc_shenandoah; Cassandra tests
>>
>