Review request: 8015268: NPG: 2.5% regression in young GC times on CRM Sales Opty

[Stefan Karlsson]

http://cr.openjdk.java.net/~stefank/8015268/webrev.00

8015268: NPG: 2.5% regression in young GC times on CRM Sales Opty
Summary: Split SystemDictionary and ClassLoaderDataGraph root processing 
to help load balancing.

The ClassLoaderDataGraph was added in the PermGen removal project and 
the he root processing of it was added to the system dictionary task, 
instead a separate phase/task. This patch splits the two tasks, so that 
they can be run in parallel.

It has been verified that this patch reduces the Parallel Scavenge young 
GC times with about 9% in the CRM Sales Opty benchmark.

thanks,
StefanK