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

[Kornel Pal]

Hi Zhengyu,

Unfortunately I am not sure whether the integration was completed, but I 
see a lot of backports happening currently.

I just wanted to make sure that this does not fall off the radar.

Thank you,
Kornel

On 2020-09-08 21:07, Zhengyu Gu wrote:
> Hi Kornel,
> 
> On 9/7/20 1:08 PM, Kornel Pal wrote:
>> Hi Zhengyu,
>>
>> Thank you for getting back to me and preparing the change this quickly.
>>
>> I'm looking forward to see the change in the nightly builds.
>>
> 
> Thanks for reporting.
> 
> The fix is reviewed and ready for pushing.
> 
> However, current shenandoah/jdk8 repo is closed for upcoming 
> integration. I will push the change once the repo is reopen.
> 
> -Zhengyu
> 
>> Thank you,
>> Kornel
>>
>> On 2020-08-28. 14:36, Zhengyu Gu wrote:
>>> 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
>>>>>
>>>>
>>>
>>
> 
> .