RFR: 8210883: ZGC: Parallel retire/resize/remap of TLABs

[Per Liden]

On 09/18/2018 10:24 PM, Per Liden wrote:
> Let ZGC retire/resize/remap TLABs in parallel. This change builds on 
> JDK-8210857 - "Allow retiring TLABs and collecting statistics in 
> parallel​", which is currently also out on review.
> 
> Bug: https://bugs.openjdk.java.net/browse/JDK-8210883
> Webrev: http://cr.openjdk.java.net/~pliden/8210883/webrev.0

While off-line reviewing with Erik we noticed that the 
ZMarkRootsIteratorClosure obviously has to be owned by the 
ZMarkRootsTask for the stat collection to work out as intended.
To be symmetric, ZRelocateRootsIteratorClosure/ZRelocateRootsTask were 
adjusted in the same way, even if it doesn't really matter in that case.

Diff: http://cr.openjdk.java.net/~pliden/8210883/webrev.0vs1
Full: http://cr.openjdk.java.net/~pliden/8210883/webrev.0

/Per