We introduced per-worker preserved mark stacks for ParNew and ParallelGC (see JDK-8146989 and JDK-8146991). Both GCs use the PreservedMarks* classes. It'd be worthwhile also changing G1 to use the same classes as the other two to get code parity between all GCs.
            
- relates to
- 
                    JDK-8146989 Introduce per-worker preserved mark stacks in ParNew -           
- Resolved
 
-         
- 
                    JDK-8146991 Introduce per-worker preserved mark stacks in ParallelGC -           
- Resolved
 
-         
- 
                    JDK-8152312 ParNew: Restore preserved marks in parallel -           
- Resolved
 
-