[master] RFR: OMWorld: reenable all platforms

[Coleen Phillimore]

On Wed, 12 Jun 2024 14:53:54 GMT, Roman Kennke <rkennke at openjdk.org> wrote:

>> This reenables all platforms to use OMWorld, and by extension UseCompactObjectHeaders. 
>> 
>> This change simply calls the runtime if a lock is inflated, until port support for OMWorld cache lookup is added.
>> 
>> ARM (32-bit) required no changes as it already always called the runtime when a monitor is inflated.
>
> src/hotspot/share/runtime/lightweightSynchronizer.cpp line 1045:
> 
>> 1043:   const markWord mark = obj->mark();
>> 1044: 
>> 1045:   if (mark.is_unlocked()) {
> 
> Was that not needed before? Or why is this added now?

Also wondering this.  We come here if the object is locked via slow path, but can it become unlocked only for the platforms that come don't check the ObjectMonitor and go slow path?

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PR Review Comment: https://git.openjdk.org/lilliput/pull/174#discussion_r1636943499