RFR (S) 8232788: Move biased locking initalization

[David Holmes]

On 23/10/2019 10:37 pm, coleen.phillimore at oracle.com wrote:
> On 10/22/19 10:29 PM, David Holmes wrote:
>> Hi Coleen,
>>
>> On 23/10/2019 5:54 am, coleen.phillimore at oracle.com wrote:
>>> Summary: Move from before adding to the dictionary to during 
>>> InstanceKlass construction, which occurs right before.
>>
>> Right before? I had trouble seeing where the IK was created relative 
>> to the call to SD::update_dictionary. But I don't think it really 
>> matters as long as the biased locking state is set before the new IK 
>> gets added to the SD.
> 
> Right.  The InstanceKlass is parsed or loaded from the shared archive, 
> then added to the SD.   Nothing else gets to see the InstanceKlass until 
> then.
> 
>>
>> But I don't understand the change to restore_shareableinfo. Where 
>> would the biased locking state get set on that code path today?
> 
> Today, it's updated in update_dictionary in the case where the klass is 
> loaded from the shared archive.

Okay. I can't track where update_dictionary gets called in relation to 
the use of load_shared_class and the subsequent call to 
restore_unshareable_info.

>  With this simple change, it's done in 
> the constructor and removing this code from SystemDictionary that 
> shouldn't know anything about it.

I agree SD shouldn't need to know about it.

Thanks,
David

> Coleen
> 
>>
>> Thanks,
>> David
>>
>>> Tested with tier1 all Oracle platforms, tier 2-3, linux-x64-debug, 
>>> tier1 with -XX:BiasedLockingDelay=100, and gtest with 
>>> -XX:-UseBiasedLocking.
>>>
>>> open webrev at 
>>> http://cr.openjdk.java.net/~coleenp/2019/8232788.01/webrev
>>> bug link https://bugs.openjdk.java.net/browse/JDK-8232788
>>>
>>> Thanks,
>>> Coleen
>