RFR: 8210061: ZGC: Remove STW weak processor mode

[Erik Österlund]

Hi Per,

Thanks for the review. Will remove the unused stat counters before pushing.

/Erik

On 2018-08-29 08:31, Per Liden wrote:
> Hi,
>
> On 08/28/2018 11:58 AM, Erik Österlund wrote:
>> Hi,
>>
>> ZGC has multiple modes for processing weaks. ZWeakRoots allows 
>> treating weaks as strong, and in addition to that, 
>> ZConcurrentStringTable, ZConcurrentVMWeakHandles and 
>> ZConcurrentJNIWeakGlobalHandles allow certain subsets of weak roots 
>> to be processed concurrently or in a pause. Except there is no 
>> obvious reason why you would ever opt out of doing it concurrently. 
>> So I propose to remove this functionality.
>> Part of the motivation is that a concurrent strong root processor is 
>> on its way, and all these modes nobody uses leads to pointless 
>> complexity.
>>
>> Webrev:
>> http://cr.openjdk.java.net/~eosterlund/8210061/webrev.00/
>
> Looks good. One thing though, you also want to remove the following 
> stat phases, as they are no longer used:
>
> ZSubPhasePauseWeakRootsVMWeakHandles
> ZSubPhasePauseWeakRootsJNIWeakHandles
> ZSubPhasePauseWeakRootsStringTable
>
> I don't need to see a new webrev.
>
> cheers,
> Per
>
>>
>> Bug:
>> https://bugs.openjdk.java.net/browse/JDK-8210061
>>
>> Thanks,
>> /Erik