Request for review (M): 6976060 G1: humongous object allocations should initiate marking cycles when necessary

[Bengt Rutisson]

Hi again,

Updated webrev with just one change compared to the last one. Tony 
pointed out that I mixed one of the if statements a bit based on his 
initial comments. Thanks Tony for catching it!

http://cr.openjdk.java.net/~brutisso/6976060/webrev.05/

Bengt

On 2012-01-16 15:22, Bengt Rutisson wrote:
>
> Hi again,
>
> Updated webrev based on comments from Tony:
> http://cr.openjdk.java.net/~brutisso/6976060/webrev.04/
>
> Thanks, Tony for the review! Still need one more...
>
> Bengt
>
> On 2012-01-12 23:26, Bengt Rutisson wrote:
>>
>> Hi all,
>>
>> Could I have a couple of reviews for this fix?
>> http://cr.openjdk.java.net/~brutisso/6976060/webrev.03/
>>
>> 6976060 G1: humongous object allocations should initiate marking 
>> cycles when necessary
>> http://monaco.us.oracle.com/detail.jsf?cr=6976060
>> http://bugs.sun.com/bugdatabase/view_bug.do?bug_id=6976060
>>
>> Background:
>>
>> We can hit the threshold where we should initiate a concurrent 
>> marking cycle when we do humongous allocation. This fix will check 
>> that threshold after each humongous object allocation to make sure 
>> that we don't miss the chance to run a concurrent mark and have to 
>> revert to full GCs.
>>
>> Testing:
>> I wrote a small Java app that only allocates humongous objects. 
>> Before my fix I get only full GCs. With my change I avoid full GCs 
>> all together.
>>
>> Thanks,
>> Bengt
>