RFR: 8204554: JFR TLAB tracing broken after 8202776

Thomas Schatzl thomas.schatzl at oracle.com
Mon Jun 11 09:34:10 UTC 2018


On Thu, 2018-06-07 at 16:27 +0200, Erik Österlund wrote:
> Hi,
> 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.

  looks good.


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