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

Mandy Chung mandy.chung at oracle.com
Tue Sep 6 17:49:38 PDT 2011


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.

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.

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

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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