[15] RFR 8245240: Shenandoah: support nesting evacuation OOM scope

[Aleksey Shipilev]

On 5/19/20 2:15 PM, Zhengyu Gu wrote:
> Bug: https://bugs.openjdk.java.net/browse/JDK-8245240
> Webrev: http://cr.openjdk.java.net/~zgu/JDK-8245240/webrev.00/index.html

I haven't looked through the state machine in more detail, but just a few coding nits:

 *) Do we really want to merge both _nesting_level and _is_evac_oom in the same field? Why can't we
do it in separate fields? If we do want them to share a byte, I think we have to assert that writes
to that byte field only happen from the same thread. Otherwise word-tearing bites us.

 *) This is just "if (level != 0)", right?

  88   // Not top level, just return
  89   if (level > 1) {
  90     return;
  91   }

-- 
Thanks,
-Aleksey