Timeline for BiasedLocking removal?

[Roman Kennke]

Good. Does obsoletion mean it can be removed altogether?

If nobody's signed up for it yet, I could also handle the actual removal.

Thanks,
Roman

> JDK-8256425 Obsolete Biased Locking in JDK 18
> https://bugs.openjdk.java.net/browse/JDK-8256425
> 
> On 5/11/21 9:50 AM, Roman Kennke wrote:
>> Hi Hotspot devs,
>>
>> what is the timeline for removing BiasedLocking altogether? Or have we 
>> even agreed that we are going to remove it?
>>
>> I am asking because this affects how I'd move forward with Lilliput. 
>> If I can ignore BiasedLocking because it'd be removed in, say, JDK 18 
>> anyway, then I believe I can come up with a relatively simple 
>> implementation for 64bit header that should be possible to integrate 
>> into JDK 18. That is, I put the (compressed) Klass* in the upper bits 
>> of the header, also keep the hashcode in the header, and keep 
>> everything else (locking, GC bits) as they are.
>>
>> With biased-locking, the Klass* would clash with the Thread* in the 
>> upper bits. If we are not going to remove BiasedLocking anytime soon, 
>> I would have to come up with a different plan.
>>
>> (Also, note that I expect the performance improvement of Lilliput to 
>> outweight possible - and hopefully rare - biased-locking removal 
>> regressions)
>>
>> WDYT?
>>
>> Cheers,
>> Roman
>>
>