request for review (M): 4965777 GC changes to support use of discovered field for pending references

Y. S. Ramakrishna y.s.ramakrishna at oracle.com
Tue Sep 6 17:56:32 PDT 2011


Hi Mandy --

On 09/06/11 17:49, Mandy Chung wrote:
> Hi Ramki,
> 
> I reviewed the JDK webrev:
>> JDK webrev:   http://cr.openjdk.java.net/~ysr/4965777/jdk/webrev/
> 
> The change looks good.  I ran the JCK tests on solaris-i586
> that I can reproduce the bug with JDK 7 and verify that they pass
> with your fix.

Thanks for the review, the testing and for your help with this CR.

> 
> It'd be good to write a regression test for this bug to be included
> in the jdk fix.  I can help writing it if you want.

Yes, that would be great if you could help write that, Mandy.
I'll contact you off-line on that.

> 
> I didn't review the hotspot change but had a quick scan on it.
> There is a typo "ir" in referenceProcessor.hpp L302 that I think you
> meant "or"
> 
> 302   // and thus whether ir not it uses the discovered field to chain

I'll fix that.

-- ramki

> 
> Thanks for fixing this long standing bug.
> Mandy
> 
> On 9/5/11 2:16 AM, Ramki Ramakrishna wrote:
>>
>> CR's 4243978 and  4268317 have proposed to use the discovered field of
>> a java.lang.ref.reference object to link the objects in the pending list.
>> This requires changes in both GC and in the reference handler code.
>> The JVM adaptsso as to allow it to run either inside a newer JDK which 
>> uses the
>> discovered field to link the references or inside an older JDK which 
>> uses the
>> next field for that purpose. Although the JDK part of the changes are
>> also being submitted for review here, that part will be integrated as 
>> a separate
>> CR and changeset into the JDK repo following the integration of the 
>> JVM changes
>> into an appropriate version of the HotSpot (express) repos.
>>
>>   JVM webrev:  http://cr.openjdk.java.net/~ysr/4965777/hotspot/webrev/
>>   JDK webrev:   http://cr.openjdk.java.net/~ysr/4965777/jdk/webrev/
>>
>> Many thanks to Mandy Chung and John Coomes for advice and for
>> earlier reviews; and to Mandy for additional testing help.
>>
>> Thanks for any other reviews or comments.
>> -- ramki
> 


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