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List:       openjdk-serviceability-dev
Subject:    Re: RFR (T) 8241320: The ClassLoaderData::_is_unsafe_anonymous field is unused in the SA
From:       coleen.phillimore () oracle ! com
Date:       2020-03-20 19:28:36
Message-ID: 599f317f-2330-248e-d456-3fb506090abf () oracle ! com
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On 3/20/20 11:11 AM, serguei.spitsyn@oracle.com wrote:
> 
> On 3/20/20 04:28, coleen.phillimore@oracle.com wrote:
> > 
> > 
> > On 3/19/20 6:43 PM, David Holmes wrote:
> > > Hi Coleen,
> > > 
> > > On 20/03/2020 5:46 am, coleen.phillimore@oracle.com wrote:
> > > > Summary: remove unused code that is changing in Hotspot for hidden 
> > > > classes.
> > > 
> > > I'm not sure how to identify unused code in the SA given that it 
> > > exposes a Java API for querying the JVM internals. You say 
> > > getisUnsafeAnonymous() is unused because nothing in the SA calls it. 
> > > But the same would seem to be true for other parts of the CLD API - 
> > > for example
> > > 
> > > - ClassLoaderData::dictionary() is called from
> > > - ClassLoaderData::allEntriesDo, is called from
> > > - ClassLoaderDataGraph::allEntriesDo, is called from
> > > - nowhere ???
> > 
> > Actually I had a look at that too because, of course, I was trying to 
> > remove more.  I think there is a caller for that:
> > 
> > utilities/soql/sa.js: 
> > sa.sysDict["allEntriesDo(sun.jvm.hotspot.classfile.ClassLoaderDataGraph.ClassAndLoaderVisitor)"](visitor);
> >  
> > But I don't know what the java script interface to SA is.  So I 
> > thought I'd leave it for now.  It might actually be useful 
> > theoretically.
> 
I had second thoughts about it being useful from SA.  I think if we 
wanted to see what classes were loaded in the system dictionary for each 
loader, we could write a pretty simple python script from within gdb to 
do so.

Coleen

> We have a plan to remove the java script support from SA.
> Chris P. investigated this and, probably, can tell more.
> 
> Thanks,
> Serguei
> 
> > 
> > Thanks,
> > Coleen
> > 
> > > 
> > > David
> > > -----
> > > 
> > > > Ran tier1-3 tests.  See bug for more details.
> > > > 
> > > > open webrev at 
> > > > http://cr.openjdk.java.net/~coleenp/2020/8241320.01/webrev
> > > > bug link https://bugs.openjdk.java.net/browse/JDK-8241320
> > > > 
> > > > Thanks,
> > > > Coleen
> > 
> 


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