RFR: Hole in CAS barrier when using traversal heuristics

[Zhengyu Gu]

> 
> We have a little naming problem here. While we're using G1's SATB buffer 
> to enqueue objects, the traversal GC algorithm is *not* SATB-based. It 
> is incremental-update-based, which is kindof the opposite of SATB. (one 
> could call it 'snapshot-at-the-end' (-of-traversal). Instead of enqueing 
> the previous values on stores, it enqueues the *new* values on stores. 
> This is why the storeval barrier can do both enqueue (for i-u) and WB 
> (for update-refs-consistency) in one swoop.
> 
> I hope this clarifies it. ?
Okay, I guess I have to catch up this :-(

Thanks,

-Zhengyu

> 
> Roman