RFR: 8225255: Make SATB qset lock-free

[Thomas Schatzl]

Hi,

On Wed, 2019-06-19 at 14:10 -0400, Kim Barrett wrote:
> Please review this refactoring of the PtrQueueSet hierarchy to allow
> the elimination of the completed buffer lock for SATBMarkQueueSet.
> 

[...]
> 
> CR:
> https://bugs.openjdk.java.net/browse/JDK-8225255
> 
> Webrev:
> http://cr.openjdk.java.net/~kbarrett/8225255/open.00/
> 
> Testing:
> mach5 tier1-5
> local extended gcbasher.
> 

Looks good.

Thomas