RFR(S): 8151808: Factor G1 heap sizing code out of the G1CollectorPolicy

Tom Benson tom.benson at oracle.com
Tue Mar 15 18:18:39 UTC 2016

Hi Mikael,
I noticed that g1HeapSizingPolicy.hpp defines 
NumPrevPausesForHeuristics, which is also defined in your new 
g1Measurements.hpp header.  I think it should only be in the latter.  
And as long as you're in g1HeapSizingPolicy.hpp, could you stick a blank 
line before line 42, "// Ratio check data..."?  8^)

Aside from that, looks good.

On 3/15/2016 9:40 AM, Mikael Gerdin wrote:
> Hi all,
> The code responsible for determining the heap expansion amount is 
> currently part of the class G1CollectorPolicy. The computations and 
> data required by this functionality is completely independent of the 
> other pieces of the class and could be moved to class of its own.
> One could of course imagine that there could be situations where the 
> sizing of the heap is influenced by the more general collector policy 
> but there is nothing preventing that with the new model. The only 
> difference would be that there would be a need for clearer API for 
> such influences.
> The patch is based on 8151711 and 8151637 but can be delivered 
> separately, I just have them all in the same workspace.
> Bug: https://bugs.openjdk.java.net/browse/JDK-8151808
> Webrev: http://cr.openjdk.java.net/~mgerdin/8151808/webrev.0/
> Testing: JPRT, RBT GC Testing
> Perf testing in aggregate with some other policy changes shows no 
> regressions or improvements.
> /Mikael

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