Integrated: 8308469: [PPC64] Implement alternative fast-locking scheme

[Martin Doerr]

On Sat, 20 May 2023 15:32:29 GMT, Martin Doerr <mdoerr at openjdk.org> wrote:

> New alternative fast-locking scheme for PPC64. Mostly implemented like on other platforms.
> Differences (also explained by comments in code):
> - Not using C2HandleAnonOMOwnerStub because the C2 code is reused for native wrappers.
> - Implemented a helper function `MacroAssembler::atomically_flip_locked_state` which makes it much easier to implement fast_lock/unlock for PPC64 (mainly because of register constraints in C1).
> - Using acquire/release barriers only for locking/unlocking.
> 
> I have changed the C2 code to use ConditionRegister CR0 which fits better to the new locking code. Therefore, I have adapted the other modes to work with that, too.
> Note that we don't support RTM with new locking modes. That feature will probably get removed in a future JDK version. (Already unsupported with Power10.)

This pull request has now been integrated.

Changeset: 0ab09630
Author:    Martin Doerr <mdoerr at openjdk.org>
URL:       https://git.openjdk.org/jdk/commit/0ab09630c6af42cb4d65a79a2ddd7799443e73ee
Stats:     390 lines in 7 files changed: 233 ins; 33 del; 124 mod

8308469: [PPC64] Implement alternative fast-locking scheme

Reviewed-by: rrich, lucy

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PR: https://git.openjdk.org/jdk/pull/14069