RFR: 8142402: G1 should not redirty cards in free regions

[Erik Helin]

And StefanK spotted that we no longer need to use
G1CollectedHeap::heap() in G1RedirtyLoggedCardsTasks since we store a
pointer to G1CollectedHeap in the field _g1h. Please see new webrevs:

- incremental
http://cr.openjdk.java.net/~ehelin/8142402/webrev.01-02/
- full:
http://cr.openjdk.java.net/~ehelin/8142402/webrev.02/

Thanks,
Erik

On 2015-11-10, Erik Helin wrote:
> All,
> 
> I just rebased the patch and discovered that heap_region_containing_raw
> has been renamed to heap_region_containing. Please see new webrevs:
> 
> - incremental:
> http://cr.openjdk.java.net/~ehelin/8142402/webrev.00-01/
> - full:
> http://cr.openjdk.java.net/~ehelin/8142402/webrev.01/
> 
> Thanks,
> Erik
> 
> On 2015-11-10, Erik Helin wrote:
> > Hi all,
> > 
> > this patch ensures that G1 does not redirty cards for regions that are
> > free. This not a problem for product builds, but it causes the card
> > verification code to fail in debug builds, which is annoying.
> > 
> > Enhancement:
> > https://bugs.openjdk.java.net/browse/JDK-8142402
> > 
> > Webrev:
> > http://cr.openjdk.java.net/~ehelin/8142402/webrev.00/
> > 
> > Testing:
> > JPRT
> > 
> > Thanks,
> > Erik