RFR: Add new pinned/cset region state for evac-failure-path

[Aleksey Shipilev]

On 11/08/2017 02:13 PM, Roman Kennke wrote:
> All that the patch does is introduce legal region state changes for the exceptional path: suppose
> we'd try to do without pinned_cset, what could we do when pinning a cset region? We can make it
> pinned, but lose the info that it was cset, and then when unpinning, go back to regular? This sounds
> wrong.

Yes, okay then. I was worried that another pinned state makes Full GC complain. If it is not, we are
fine.
> http://cr.openjdk.java.net/~rkennke/pinned-cset/webrev.01

Good, but not enough, add this:
  http://cr.openjdk.java.net/~shade/shenandoah/pinned-cset-1.patch

-Aleksey