[11u] RFR(S): 8241234: Unify monitor enter/exit runtime entries.

[Doerr, Martin]

Hi Andrew,

> Why is anyone backporting a P4 Enhancement? Seems weird.
This is a good question in general. Personally, I'd vote for backporting fewer less important things to 11u in the future. We should better focus on 17 IMHO.

However, there are some arguments for backporting this one:
- Oracle has done so. There may be more backports in this area and I'd expect less effort if we have the same code in the open version.
- Performance is supposed to be better. (Though I didn't measure it.)
- New code is much cleaner. Let's keep in mind that we have to support it for quite a while.

Are you ok with it?

Best regards,
Martin


> -----Original Message-----
> From: Andrew Haley <aph at redhat.com>
> Sent: Donnerstag, 27. August 2020 11:45
> To: Doerr, Martin <martin.doerr at sap.com>; 'hotspot-compiler-
> dev at openjdk.java.net' <hotspot-compiler-dev at openjdk.java.net>; jdk-
> updates-dev at openjdk.java.net
> Cc: Lindenmaier, Goetz <goetz.lindenmaier at sap.com>
> Subject: Re: [11u] RFR(S): 8241234: Unify monitor enter/exit runtime entries.
> 
> On 17/08/2020 22:54, Doerr, Martin wrote:
> > Hi,
> >
> > I'd like to backport https://bugs.openjdk.java.net/browse/JDK-8241234 to
> JDK11u.
> >
> > Original JDK15 patch
> (https://hg.openjdk.java.net/jdk/jdk/rev/87c506c8be63) doesn't fit to
> JDK11u because the locking code has been reworked by
> https://bugs.openjdk.java.net/browse/JDK-8229844
> > As mentioned by Vladimir, there's already a GraalVM version available
> which consists of 2 patches (original + addon) and which can be applied:
> > https://github.com/graalvm/labs-openjdk-
> 11/commit/6c162cb15262e6aa77e36eb3a268320ef0a206a4
> > https://github.com/graalvm/labs-openjdk-
> 11/commit/6a28a618cdbe595f9a3993e0eb63c01ccae1a528
> > Only JVMCI part from GraalVM doesn't apply automatically. The version of
> this file from JDK15 is very simple and fits perfectly.
> >
> > Please review the JDK11u backport webrev:
> >
> http://cr.openjdk.java.net/~mdoerr/8241234_monitorenterexit_11u/webre
> v.00/
> 
> Why is anyone backporting a P4 Enhancement? Seems weird.
> 
> 
> --
> Andrew Haley  (he/him)
> Java Platform Lead Engineer
> Red Hat UK Ltd. <https://www.redhat.com>
> https://keybase.io/andrewhaley
> EAC8 43EB D3EF DB98 CC77 2FAD A5CD 6035 332F A671