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

[Zhengyu Gu]

Hi Kornel,

Thanks for reminding me. The patch is ready to go, I will run some 
tests, should push soon.

Thanks,

-Zhengyu

On 12/2/20 11:27 AM, Kornel Pal wrote:
> 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
>>>>>>
>>>>>
>>>>
>>>
>>
>> .
>