[aarch64-port-dev ] RFR: Shenandoah import

[Roman Kennke]

Thanks for all the reviews so far.

In the meantime we've got two more changes that seem important to 
include. One is another improvement for Shenandoah isolation from 
Roland, and the other is a fix for a nasty deadlock (in Shenandoah) that 
only occurs in jdk8.

http://cr.openjdk.java.net/~rkennke/jdk8u-shenandoah-integration-2017-10-02/webrev.01/ 
<http://cr.openjdk.java.net/%7Erkennke/jdk8u-shenandoah-integration-2017-10-02/webrev.01/>

When ok, I'll push this together with the earlier changesets to the 
intergration repo.

Roman

> This imports Shenandoah changes from shenandoah/jdk8u/hotspot into the 
> integration repository aarch64-port/jdk8u-shenandoah/hotspot .
>
> It includes (and thus supercedes) changes proposed here:
>
> http://mail.openjdk.java.net/pipermail/aarch64-port-dev/2017-August/004854.html 
>
>
> Instead of doing bulk-import I went back to transplanting 
> single-changeset import. I can avoid the merge conflicts simply by not 
> merging back from aarch64-port/jdk8u-shenandoah but instead from 
> aarch64-port/jdk8u. Plus we get the benefit of preserving the original 
> changesets, make bisecting more useful, etc.
>
> It also includes newer backports from Aug 21 - today.
>
> Everything has been extensively tested and baked in Shenandoah land.
>
> Notably, it includes a bunch of changes done by Roland that better 
> isolates Shenandoah specific code paths in C2 (thus minimizing 
> Shenandoah exposure in non-Shenandoah runs).
>
> Besides that, all of it is bugfixing plus performance and usability 
> improvements.
>
> The complete list of changesets is here:
>
> http://cr.openjdk.java.net/~rkennke/jdk8u-shenandoah-integration-2017-10-02/changesets.txt 
> <http://cr.openjdk.java.net/%7Erkennke/jdk8u-shenandoah-integration-2017-10-02/changesets.txt> 
>
>
> The total webrev is here:
>
> http://cr.openjdk.java.net/~rkennke/jdk8u-shenandoah-integration-2017-10-02/webrev.00/ 
> <http://cr.openjdk.java.net/%7Erkennke/jdk8u-shenandoah-integration-2017-10-02/webrev.00/> 
>
>
> Please review! Thanks, Roman
>