[master] RFR: 8300440: [Lilliput] Implement alternative fast-locking scheme

[Aleksey Shipilev]

On Wed, 18 Jan 2023 08:14:51 GMT, Roman Kennke <rkennke at openjdk.org> wrote:

> This cherry-picks https://github.com/openjdk/jdk/pull/10907 before it lands in mainline JDK. It will:
> - Greatly simply access to the header in the face of racy stack-locking
> - Enable some optimizations in various places, most importantly accessing Klass* and i-hash
> - Enable full SA support
> - Enable full ZGC support
> - Enable adding a runtime flag to turn on/off Lilliput
> 
> However, this PR implements none of the above. It is a straight port of the upstream change, and fast-locking is *not yet* enabled with Lilliput. This is going to happen in a follow-up PR.
> 
> Testing and performance impact, see upstream PR.
> 
> Ok to push to Lilliput?

OK for Lilliput.

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Marked as reviewed by shade (Committer).

PR: https://git.openjdk.org/lilliput/pull/62