RFR: 8210063: ZGC: Enable load barriers for IN_NATIVE runtime barriers

[Erik Österlund]

Hi Per,

Thanks for the review. Will sort that out before pushing.

/Erik

On 2018-08-29 08:45, Per Liden wrote:
> On 08/28/2018 01:03 PM, Erik Österlund wrote:
>> Hi,
>>
>> In an effort to scan more (strong) root sets concurrently, we need to 
>> support IN_NATIVE oops not being fixed up in safepoints. Both the 
>> ZBarrierSetAssembler, ZBarrierSetC1 and ZBarrierSetC2 already have 
>> IN_NATIVE load barriers on for all strong oops. However, ZBarrierSet 
>> does not yet enable it. I propose to enable it so we can scan more 
>> things concurrently.
>>
>> Webrev:
>> http://cr.openjdk.java.net/~eosterlund/8210063/webrev.00/
>
> Looks good. I think we should also add an 
> verify_decorators_absent<ON_UNKNOWN_OOP_REF>(), like we do in 
> "in_heap" version of oop_load. If nothing else, just to keep these in 
> sync with each other.
>
> /Per
>
>>
>> Bug:
>> https://bugs.openjdk.java.net/browse/JDK-8210063
>>
>> Thanks,
>> /Erik