RFR: JDK-8079556: BACKOUT - Determining the desired PLAB size adjusts to the the number of threads at the wrong place

[Bengt Rutisson]

On 2015-05-07 10:34, Jesper Wilhelmsson wrote:
> Hi,
>
> Please review this backout of JDK-8073204 - Determining the desired 
> PLAB size adjusts to the the number of threads at the wrong place
>
> After the change the size returned by PLABStats::desired_plab_sz() can 
> get below the minimum PLAB size due to truncating integer division in 
> that function, and actually missing alignment. This results in several 
> places getting the wrong results because of this broken invariant.
>
> The fix will take more than a day and this change is now blocking a 
> push of hs-gc to main.
>
> Thomas prepared this backout, I have reviewed it (looks good), so we 
> need another Reviewer to push it.
>
> Backout bug: https://bugs.openjdk.java.net/browse/JDK-8079556
> Webrev: http://cr.openjdk.java.net/~jwilhelm/8073204/webrev_backout.00/
> Original change: 
> http://hg.openjdk.java.net/jdk9/hs-gc/hotspot/rev/d57d15fb074b
>
> The backout applies cleanly to latest hs-gc.

Looks good.

Bengt

>
> Thanks,
> /Jesper