[10u] RFA: JDK-8203305 and JDK-8203669 (RTM fixes for POWER9)

[Gustavo Romero]

Hi,

Some distro releases, notably Ubuntu 18.04 LTS "Bionic Beaver", are already
shipping OpenJDK 10. Ubuntu 18.04 is able to run on the new POWER9
machines. On some of these new POWER9 machines the JVM won't be able to
detect a new POWER9 TM mode (called "TM with No Suspend mode") and will
halt on checking if the JVM is capable of enabling the RTM feature (which
depends upon TM).

So I would like to request the approval to backport the following two
changes to 10u that address this issue on POWER9 DD2.1:

Title        : RFR(XS): 8203305: PPC64: Improve TM detection for enabling RTM on Linux / POWER9 [1]
Bug          : https://bugs.openjdk.java.net/browse/JDK-8203305
Review thread: http://mail.openjdk.java.net/pipermail/hotspot-dev/2018-May/032313.html
Patch        : http://hg.openjdk.java.net/jdk/jdk/raw-rev/e2d9b38630c3

Title        : RFR(S) : 8203669: PPC64: Fix jtreg RTM tests after "8203305: Improve TM detection for enabling RTM on Linux / POWER9" [2]
Bug          : https://bugs.openjdk.java.net/browse/JDK-8203669
Review thread: http://mail.openjdk.java.net/pipermail/hotspot-compiler-dev/2018-May/029091.html
Patch        : http://hg.openjdk.java.net/jdk/jdk/raw-rev/ede65c4fb6da

Both changes apply cleanly to 10u except for small offsets.

Change [1] is PPC-only. Change [2] touches shared code but it just changes
a jtreg test in regard to PPC and fixes a few typos. Although changes [1]
and [2] are marked as "Enhancement" in the JBS, I understand that they
actually fit the "CPU fix merges" as found on Rule 3, in the Request
for Approval rules [3].

Thank you.


Best regards,
Gustavo

[3] http://openjdk.java.net/projects/jdk-updates/approval.html