CRR (S): 7046182: G1: remove unnecessary iterations over the collection set

[John Cuthbertson]

Hi Tony,

I'm looking at it now - should be done very shortly.

JohnC

On 06/20/11 14:25, Tony Printezis wrote:
> Hi,
>
> I have one code review for this (from Bengt). Any chance of getting a 
> second one to get it off my plate? Thanks.
>
> Tony
>
> On 06/13/2011 01:16 PM, Tony Printezis wrote:
>> Hi all,
>>
>> Could I have a couple of code reviews for this change?
>>
>> http://syros.us.oracle.com/local_ws/hotspot-g1-cset-iter/webrev/
>>
>> Basically, we (unnecessarily) iterate over the collection set a 
>> couple of times during each GC to reset two fields on the RSet data 
>> structure. It's better to make sure that those fields are reset when 
>> the region is freed (so it's "ready to go" when it's re-allocated) to 
>> avoid those two iterations.
>>
>> I added some extra code to assert that these two fields are in the 
>> correct state before each GC and I also added an extra verification 
>> step on the master free list to also check that condition on all the 
>> regions on it (since the two fields in question should be reset 
>> before the region is added to the master free list).
>>
>> I'm piggy-backing the removal of the G1_REM_SET_LOGGING code on this 
>> (it's kinda related as it also iterates over the collection set - so, 
>> we remove more collection set iterations!). We haven't used it for a 
>> while and it's helpfulness is marginal.
>>
>> Thanks,
>>
>> Tony
>>
>>