RFR: 8365190: Remove LockingMode related code from share

[Fredrik Bredberg]

On Tue, 2 Sep 2025 20:19:06 GMT, Coleen Phillimore <coleenp at openjdk.org> wrote:

>> Since the integration of [JDK-8359437](https://bugs.openjdk.org/browse/JDK-8359437) the `LockingMode` flag can no longer be set by the user. After that, a number of PRs has been integrated which has removed all `LockingMode` related code from all platforms (except from zero, which is done in this PR).
>> 
>> This PR removes `LockingMode` related code from the shared (non-platform specific) files. It also removes the `LockingMode` variable itself.
>> 
>> Passes tier1-tier5 with no added problems.
>
> src/hotspot/share/runtime/javaThread.cpp line 2007:
> 
>> 2005: #ifdef SUPPORT_MONITOR_COUNT
>> 2006:   // Nothing to do. Just do some sanity check.
>> 2007:   assert(_held_monitor_count == 0, "counter should not be used");
> 
> In further cleanup, can we now remove _held_monitor_count next?

I think so, but I'm not sure. Anyhow I've added this to o the [next cleanup](https://bugs.openjdk.org/browse/JDK-8365191).

> src/hotspot/share/runtime/synchronizer.inline.hpp line 48:
> 
>> 46:   assert(current == Thread::current(), "must be");
>> 47: 
>> 48:     LightweightSynchronizer::enter(obj, lock, current);
> 
> In the further RFE, we should remove these dispatch functions too.

Added this to o the [next cleanup](https://bugs.openjdk.org/browse/JDK-8365191).

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PR Review Comment: https://git.openjdk.org/jdk/pull/27041#discussion_r2321483375
PR Review Comment: https://git.openjdk.org/jdk/pull/27041#discussion_r2321488805