On Wed, 26 Aug 2026 15:48:38 GMT, Axel Boldt-Christmas <[email protected]> 
wrote:

> The interface on oopDesc and the markWord w.r.t. the locking bits have grown 
> overtime the names do not reflect what they actually do, there are multiple 
> ways of asking for the same property.
> 
> The properties `is_locked` and `is_unlocked` are misleading. As the answer 
> true of false does not necessarily reflect the locking state of the object. I 
> suggest we use a single terminology `is_fast_locked` to mean the locking bits 
> are locked using lightweight non-monitor locking and `is_neutral` to mean the 
> locking bits are in the prototype state.
> 
> Using `is_fast_unlocked` could be an alternative to `is_neutral`, but 
> `is_neutral` captures the state better of being an object which is currently 
> not taking part in locking. However the name does not make it obvious that it 
> is referring to the locking state / mark state. Not 100% on this naming, and 
> how the comments and code which uses these constants in the MacroAssembler 
> should name and deal with this.
> 
> Also cleaned up the C1 and C2 Valhalla header bits checks which were gated on 
> the locking bits. There is not more displaced header so conditionally 
> checking the prototype header in the Klass* is not needed.
> 
> Testing (in progress):
> * Tier 1-5 Oracle supported platforms
> * GHA
> 
> ---------
> - [x] I confirm that I make this contribution in accordance with the [OpenJDK 
> Interim AI Policy](https://openjdk.org/legal/ai).

This pull request has now been integrated.

Changeset: c9281180
Author:    Axel Boldt-Christmas <[email protected]>
URL:       
https://git.openjdk.org/jdk/commit/c92811804f8c4db057c2680c835d9c55fdacecf9
Stats:     538 lines in 48 files changed: 161 ins; 222 del; 155 mod

8391176: Cleanup the markWord locking bits

Co-authored-by: Roberto Castañeda Lozano <[email protected]>
Reviewed-by: rcastanedalo, thartmann, stefank, fbredberg

-------------

PR: https://git.openjdk.org/jdk/pull/32544

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