RFR: 8224974: Implement JEP 352

[Andrew Dinn]

Hi Brian,

On 06/06/2019 01:06, Brian Burkhalter wrote:
> With version 6 [1] of the patch applied, tests throw this exception:
> 
> Mapped java.lang.InternalError: java.lang.NullPointerException
> at
> java.base/jdk.internal.misc.ExtendedMapMode.newMapMode(ExtendedMapMode.java:58)
> at
> java.base/jdk.internal.misc.ExtendedMapMode.<clinit>(ExtendedMapMode.java:40)
> at java.base/sun.nio.ch.FileChannelImpl.map(FileChannelImpl.java:1007)
> 
> Looks like a problem in the initialization order of the static final
> constants: MAP_MODE_CONSTRUCTOR needs to be initialized first so I think
> the *_SYNC constants need to be after the static initializer [2].

Doh! Yes, you are right.

Sorry for adding confusion. webrev.06 was not meant to be intended for
public consumption. I uploaded it last night when I set the rebuild off
but I didn't intend to advertise it until I had retested and got your
confirmation on the suggestions I made. Anyway, thanks all the same for
reviewing it, trying to run it and also finding/fixing this issue.

I have updated webrev.06 in place and PmemTest now runs ok. I still need
to have Jonathan Halliday test the patch with our Transaction and Data
Grid software before it can be properly signed off. Another submit run
will also be needed. However, PmemTest is a good enough sanity check to
validate the changes you requested.

So, here is webrev.06 as the latest official patch:

  http://cr.openjdk.java.net/~adinn/8224974/webrev.06/

It should address

  changes requested on this list by Alan and Vladimir

  all the changes you requested in your review
  (modulo those you agreed to defer on)

  the change to correct this static init order bug

  a change to graal test CheckGraalIntrinsics to declare
  the new jdk13 intrinsics in alphanum sort order
  (this was requested offline by Alan -- without it the test
  refuses to run on jdk13)

The last of those changes still leaves one issue unanswered (although it
may not actually be an issue). Vladimir is probably best able to comment.

When I run CheckGraalIntrinsics (which is actually run indirectly by
compiler/graalunit/HotspotTest) with my patched tree it fails, claiming
that Graal does not know about Unsafe.writeback0:

  java.lang.AssertionError: missing Graal intrinsics for:
      jdk/internal/misc/Unsafe.writeback0(J)V

I am assuming this is what is expected to happen? Or perhaps the test is
supposed to be added to the problem or exclude lists?

> Sorry for suggesting the change that was the proximate cause of this. :-(
No problem :-) Thanks for reviewing and checking!

regards,


Andrew Dinn
-----------
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