[8u] RFR: Backport 8161993 G1 crashes if active_processor_count changes during startup

[Thomas Schatzl]

Hi,

On Fri, 2016-12-16 at 13:10 +1000, David Holmes wrote:
> On 16/12/2016 1:06 PM, David Holmes wrote:
> > 
> > Bug: https://bugs.openjdk.java.net/browse/JDK-8161993
> > 
> > JDK9 changeset:
> > http://hg.openjdk.java.net/jdk9/jdk9/hotspot/rev/8986e5b85e73
> > 
> > webrev: http://cr.openjdk.java.net/~dholmes/8161993/webrev.8u/
> > 
> > The changes for 8147910 are there only for reference.
> > 
> > The backport was straight-forward but couldn't apply directly due
> > to
> > file/directory renaming. Also in 9 we had already changed
> > os::processor_count() to os::active_processor_count() and then to
> > os::initial_active_processor_count(), but in 8u we skip the middle
> > step.
> Nope sorry - confused myself. In both cases we go from
> processor_count() 
> to initial_active_processor_count(). So it's even more direct than I 
> thought.

  this backport seems to contain both the changes from JDK-8147910
and JDK-8161993.
I am a bit confused what "The changes for 8147910 are there only for
reference." means. Are you intending to push the webrev as is, or only
the JDK-8161993 part?
How would that work, as JDK-8161993 is based on JDK-8147910?

If the former, I would prefer to make two separate backports, one for
each. This makes it much easier to track whether a particular issue has
already been backported or not (or is still missing).
It does not seem to be that much more effort. I will review both asap.

If this has been discussed before, and everyone agreed on that it is
for some reason better to combine the backports, ignore this.

Thanks,
  Thomas