Problematic backport to 8u: "Ensure tasks use correct number of workers"

[Zhengyu Gu]

Simply introduce ShenandoahWorkGang to bypass assertion in 
FlexibleWorkGang (and avoid contaminate upstream).

Webrev: 
http://cr.openjdk.java.net/~zgu/shenandoah/assert_workers_8u/webrev.00/

Test:

  hotspot_gc_shenandoah fastdebug + release.

-Zhengyu




On 10/02/2017 12:15 PM, Aleksey Shipilev wrote:
> On 10/02/2017 05:23 PM, Zhengyu Gu wrote:
>> Jdk8 workgang implementation is not flexible enough to support our single workgang approach. We may
>> have to provide our own implementation (although, should be simple).
> 
> Please try to do this. At very minimum, we should backport the asserts and the test, and make sure
> we pass it. In this minimum case, we might need to round up the number of concurrent and parallel
> threads to make current workgang mechanics work?
> 
> Thanks,
> -Aleksey
>