Restrictions for lock coarsening?

[Tom Rodriguez]

> It's already some time ago I looked at the biased-locking code... is  
> it
> possible at all to revoke contented locks (or CAS-based locks) to be
> biasable?  If yes, is the "not-biasable" state different to CAS-based
> lock?

It's been a while for me too so my answers aren't the final word but I  
don't think there's any implementation reason why a previously  
unbiasable object couldn't be converted back to a biasable one.  I  
think it's mainly a matter of policy and performance.  The better  
solution would be to remove the startup delay all together but I don't  
think anyone has a good idea one what it would take to do that.  The  
original decision was motivated by not allowing any regression, not  
matter how small, in the startup benchmarks.  It's possible it's not a  
big deal now but I don't think anyone has done the investigation to  
know one way or another.

tom

>
>
> - Christian
>