RFR (XS) 8230646: Epsilon does not extend TLABs to max size

[Zhengyu Gu]

Looks good to me.

-Zhengyu

On 9/5/19 7:33 AM, Aleksey Shipilev wrote:
> Bug:
>    https://bugs.openjdk.java.net/browse/JDK-8230646
> 
> I was playing with performance benchmarks and noticed that Epsilon does not extend issued TLABs to
> max tlab size, because of the simple overlook. TLAB allocation path asks GC about the max tlab size
> currently available with unsafe_max_tlab_alloc(). But, in Epsilon code, there is discrepancy: the
> caller interprets the returned value in bytes, while Epsilon code has the size in words. Every other
> GC adjusts accordingly, Epsilon should too.
> 
> Fix:
>    http://cr.openjdk.java.net/~shade/8230646/webrev.01/
> 
> Testing: gc/epsilon, jdk-submit
>