RFR: 8204554: JFR TLAB tracing broken after 8202776

[Roman Kennke]

Looks good. Go!

Thanks,
Roman

> Hi Roman,
> 
> Thanks for the review.
> StefanK thought it would be nicer to move the outside of TLAB path into
> a new function. So I did that. Hope you agree that is a good idea. If
> you want to override that behaviour you can still override
> obj_allocate_raw.
> 
> Full webrev:
> cr.openjdk.java.net/~eosterlund/8204554/webrev.01/
> 
> Incremental webrev:
> cr.openjdk.java.net/~eosterlund/8204554/webrev.00_01/
> 
> Checked again that tests pass now, and it passes.
> 
> Thanks,
> /Erik
> 
> On 2018-06-07 16:41, Roman Kennke wrote:
>> Hi Erik,
>>
>>> The recent allocation path modularization (8202776) broke JFR TLAB
>>> sampling. This was discovered in tier 5 testing.
>>>
>>> The problem is that there was previously an early exit TLAB path, that
>>> should not run the tracing code when not returning NULL, and a
>>> mem_allocate call that should run the tracing code when not returning
>>> NULL. However, these paths were joined in a virtual member function,
>>> making them look the same to the tracing code, which caused the non-TLAB
>>> tracing code to be run on TLAB allocations as well.
>>>
>>> The solution I propose is to move the TLAB tracing code into the new
>>> virtual member function. It seems that whatever GC overrides this code,
>>> should also decide what to do about the tracing code there anyway.
>>>
>>> Webrev:
>>> http://cr.openjdk.java.net/~eosterlund/8204554/webrev.00/
>>>
>>> Bug:
>>> https://bugs.openjdk.java.net/browse/JDK-8204554
>>>
>>> I have run failing tests locally to verify they have been fixed with the
>>> proposed patch. I am now running hs-tier1-3 as well, but am waiting for
>>> the results.
>> This looks good to me. Thank you!
>>
>> Roman
>>
>