RFR: 8201316: Move G1-related static members from JavaThread to G1BarrierSet

[Aleksey Shipilev]

On 04/10/2018 01:05 PM, Per Liden wrote:
> As part of the effort to make GCs more pluggable, the G1-specific data in JavaThread should be moved
> out into a more appropriate abstraction.
> 
> The first step is to move G1's static members (_satb_mark_queue_set and _dirty_card_queue_set) from
> JavaThread to the G1BarrierSet.
> 
> This will be followed up by JDK-8201318, which is a more complex change, to remove the non-static G1
> members in JavaThread.
> 
> Bug: https://bugs.openjdk.java.net/browse/JDK-8201316
> Webrev: http://cr.openjdk.java.net/~pliden/8201316/webrev.0

I actually think we should instead move SATB machinery into gc/shared (Shenandoah uses it!), and
leave these static members in the JavaThread.

See:
  https://bugs.openjdk.java.net/browse/JDK-8154343

-Aleksey