RFR(S): Ensure collection set and cset map are consistent, and a few cleanup

[Zhengyu Gu]

On 05/31/2017 02:12 PM, Aleksey Shipilev wrote:
> On 05/31/2017 08:04 PM, Zhengyu Gu wrote:
>> Added collection set/cset fast test verification code, and restricting access to
>> cset fast test map to ensure they are consistent.
>>
>> Also, eliminated unused parameters in ShenandoahPolicy code, plus a few cleanup.
>>
>> We might want to get rid of region cache in collection set. instead, just have
>> collection set to wrap around cset fast test. I will experiment this later.
>>
>> Webrev:
>> http://cr.openjdk.java.net/~zgu/shenandoah/cset_cleanup/webrev.00/index.html
>
> Excellent, this always disturbed me.
>
>  *) This looks okay, but chf's partial would trade that "int* connections"
> parameter for "ShConnMatrix*". I think that leaving this cleanup alone helps chf
> to not to rebase much:
>
>  189   virtual void choose_collection_set(ShenandoahCollectionSet*
> collection_set, int* connections=NULL);
>
OK, I will revert this.

>  *) Is removal of this branch meaningful? It was supposed to avoid some stores:
>
>  228         if (!r->is_root()) {
>  229           r->set_root(true);
>  230         }

Just a bit awkward. Do those stores matter? It is at a safepoint, and 
you have region in cache anyway.

>
>  *) I don't think looped partial GC belongs in this change. Split it out?
>
I will split this out.

Thanks,

-Zhengyu

> Thanks,
> -Aleksey
>