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

[Bengt Rutisson]

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