[lworld] RFR: 8334140: [lworld] -XX:LockingMode=0 ignored makes MapLoops fail

[Coleen Phillimore]

On Wed, 12 Jun 2024 20:16:32 GMT, Roger Riggs <rriggs at openjdk.org> wrote:

> The MapLoops test uses `-XX:LockingMode=0 -XX:+VerifyHeavyMonitors ` for a debug test run.
> However, the LockingMode command line option is overridden in arguments.cpp when 
> Valhalla is enabled and it forces the lock mode to be LM_LEGACY.
> 
> The default for lightweight locking should only be overridden if Valhalla is enabled.

Marked as reviewed by coleenp (no project role).

src/hotspot/share/runtime/arguments.cpp line 1833:

> 1831: 
> 1832:   // Valhalla missing LM_LIGHTWEIGHT support just now
> 1833:   if (EnableValhalla && LockingMode == LM_LIGHTWEIGHT ) {

Nit: remove the space after LIGHTWEIGHT.

This should work.  If lightweight locking is specified on the command line, you probably should have a warning, but I assume this is temporary until it is supported.

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PR Review: https://git.openjdk.org/valhalla/pull/1124#pullrequestreview-2114150534
PR Review Comment: https://git.openjdk.org/valhalla/pull/1124#discussion_r1637037273