RFR (S/M): 8014078: G1: improve remembered set summary information by providing per region type information

[Thomas Schatzl]

Hi,

On Tue, 2013-06-04 at 16:01 -0700, John Cuthbertson wrote:
> Hi Thomas,
> 
> I think RegionTypeCounter should inherit from _ValueObj (by means of 
> VALUE_OBJ_CLASS_SPEC).
> 
> Also a couple of nitty questions (feel free to ignore):
> 
> * Does the value parameter to RegionTypeCounter::percent_of need to be 
> passed as a pointer? It looks like you pass the address of a field in 
> the RegionTypeCounter instance and then dereference.

Fixed both things. I am not sure why the code passes the address of the
field, but this is probably a leftover of some earlier version.

I also combined the calc_percentage() function with the
RegionTypeCounter::percent_of() method as they are the same.

> * For continuous humongous would it make sense to skip them until we 
> process the StartsHumongous region and sum up the memory size and the 
> occupied value for the entire humongous region (HS and HC) before adding 
> to the humongous region counter?

Imho there is no need to do that - the memory sizes and occupancies of
HS and HC regions are completely independent. I.e. the order of
evaluation does not matter here. Doing so seems to only complicate the
code.

> Other than the above - it looks great!

Thank you. I will provide a new webrev with these changes.

Thomas