RFR: 8187809: UseMembar should be set true and deprecate the flag

[Robbin Ehn]

Thanks David!

/Robbin


On 11/09/2017 02:48 AM, David Holmes wrote:
> Looks good.
> 
> One nit below ...
> 
> On 9/11/2017 6:48 AM, Robbin Ehn wrote:
>> Hi all, please review!
>>
>> This patch set the default technique for reading thread state to memory 
>> barriers instead of using the asymmetric dekker synchronization on all platforms.
> 
> That's not quite an accurate description. The option is to use platform memory 
> barriers (+UseMembar) or the memory-serialization-page "simulated" memory 
> barrier. We still employ asymmetric Dekker synchronization.
> 
> Thanks,
> David
> 
>> We also deprecate the option and starting the removal process. There have been 
>> discussion with people involved in all platforms and we will have another 
>> discussion before obsoleting the flag to make sure no issue have been found.
>>
>> More info in CSR:
>> https://bugs.openjdk.java.net/browse/JDK-8187812
>>
>> Bug:
>> https://bugs.openjdk.java.net/browse/JDK-8187809
>>
>> Code:
>> http://cr.openjdk.java.net/~rehn/8187809/webrev/
>>
>> Thanks, Robbin