RFR 8231250: Shenandoah: Traversal GC should keep alive weak load from heap

[Zhengyu Gu]

On 9/23/19 12:37 PM, Roman Kennke wrote:
> OK.

Thanks for reviewing.

> 
> We need to have a close look at the interaction between traversal and 
> native barriers/conc roots soon.

Concurrent roots is not enabled for traversal. I think we have problem 
of hitting barriers on GC paths, which trigger side-effects of LRB.

Thanks,

-Zhengyu


> 
> Roman
> 
> 
>> Resubmit:
>> Was:  8231250: Shenandoah: Shenandoah assert_correct failed; Object 
>> klass pointer
>>
>> SAP reported that this patch did not fix the assert failure in 
>> original bug report. But the fix is legit, as JDK-8227635 did change 
>> the behavior of traversal GC, resulting it may drop keepalive for heap 
>> loads.
>>
>>
>> Bug: https://bugs.openjdk.java.net/browse/JDK-8231250
>> Webrev: http://cr.openjdk.java.net/~zgu/JDK-8231250/webrev.00/
>>
>> Test:
>>    hotspot_gc_shenandoah (fastdebug and release) on Linux x86_64
>>
>> Thanks,
>>
>> -Zhengyu
>>