RFR (S): 8138750: Clean up survivor rate group

[Mikael Gerdin]

Hi Thomas,

On 2015-10-02 14:45, Thomas Schatzl wrote:
> Hi all,
>
>    can I have reviews for the following cleanup (read deletion) of unused
> code and some better naming/moving it to a better place for some method?
>
> In particular:
> - Surv_rate_group::accum_surv_rate() is never called, so remove it and
> all code referencing _accum_surv_rate.
> - CollectorState has this method
>
>   124   bool should_propagate() const { // XXX should have a more
> suitable state name or abstraction for this
>
> that is only used for updating the survivor rate group predictors in the
> collector policy. Since it does not have anything to do with G1
> collector state, I moved it to G1CollectorPolicy, and renamed it to
> "should_update_surv_rate_group_predictors()" which is what it decides.
>
> There is a bug in that method: the current code reads
>
>    return _last_young_gc && !_in_marking_code;

This should be !_in_marking_window I suppose.

>
> which has been introduced in JDK-7097567. It should actually be:
>
>    return _last_gc_was_young && !_in_marking_window;
>
> I will fix that in JDK-8138752 to keep the cleanup separate from the bug
> fix unless someone objects.

Splitting the change up sounds good to me.

>
> CR:
> https://bugs.openjdk.java.net/browse/JDK-8138750
> Webrev:
> http://cr.openjdk.java.net/~tschatzl/8138750/webrev

Looks good.
/Mikael

> Testing:
> jprt
>
> Thanks,
>    Thomas
>
>