[PATCH] typeToVtbl of BasicTypeDataBase should not be static

[Staffan Larsen]

Coleen wrote to me privately that she is ok with the change. I have submitted a JPRT job with the change.

Thanks,
/Staffan

On 19 mar 2013, at 08:45, 云达(Yunda) <yunda.mly at taobao.com> wrote:

> cc'ing hotspot-runtime for an official Review.
>  
> Regards,
> Yunda
>  
> From: Staffan Larsen [mailto:staffan.larsen at oracle.com] 
> Sent: Tuesday, March 05, 2013 9:18 PM
> To: 云达(Yunda)
> Cc: serviceability-dev at openjdk.java.net
> Subject: Re: [PATCH] typeToVtbl of BasicTypeDataBase should not be static
>  
> Yunda,
>  
> Thanks for the patch. I have created issue JDK-8009456 to track this and can sponsor the fix as soon as we get a Review of the fix.
>  
> /Staffan
>  
> On 28 feb 2013, at 04:59, 云达(Yunda) <yunda.mly at taobao.com> wrote:
> 
> 
> Hi all,
>  
> I found that when I detached a java process and attached another java process, the “universe” command of CLHSDB didn’t show the right information. But when I restarted CLHSDB and attached to the same process the problem disappeared:
>  
> hsdb> attach 29211
> Attaching to process 29211, please wait...
> hsdb> universe
> Heap Parameters:
> ParallelScavengeHeap [ PSYoungGen [ eden =  [0x00000000ee200000,0x00000000ee289aa8,0x00000000eef70000] , from =  [0x00000000ef1a0000,0x00000000ef1a0000,0x00000000ef3d0000] , to =  [0x00000000eef70000,0x00000000eef70000,0x00000000ef1a0000]  ] PSOldGen [  [0x00000000ca600000,0x00000000ca600000,0x00000000cc9c0000]  ]  ] hsdb>
> hsdb> detach
> hsdb> attach 29887
> Attaching to process 29887, please wait...
> hsdb> universe
> Heap Parameters:
> unknown subtype of CollectedHeap @ 0x0000000000d56fb0 (0x00000000ca600000,0x0000000100000000)
> hsdb> quit
> [~]$ java -cp .:$JAVA_HOME/lib/sa-jdi.jar sun.jvm.hotspot.CLHSDB
> hsdb> attach 29887
> Attaching to process 29887, please wait...
> hsdb> universe
> Heap Parameters:
> ParallelScavengeHeap [ PSYoungGen [ eden =  [0x00000000ee200000,0x00000000ee289a68,0x00000000eef70000] , from =  [0x00000000ef1a0000,0x00000000ef1a0000,0x00000000ef3d0000] , to =  [0x00000000eef70000,0x00000000eef70000,0x00000000ef1a0000]  ] PSOldGen [  [0x00000000ca600000,0x00000000ca600000,0x00000000cc9c0000]  ]  ] hsdb>
>  
> I think it’s caused by the wrong definition of “typeToVtbl” field of BasicTypeDataBase. Since typeToVtbl should be recreated every time SA attaches to a new process, it should not be static. So I made a small patch fo fix it:
>  
> diff -r ec2eddfed950 agent/src/share/classes/sun/jvm/hotspot/types/basic/BasicTypeDataBase.java
> --- a/agent/src/share/classes/sun/jvm/hotspot/types/basic/BasicTypeDataBase.java     Tue Feb 26 14:09:52 2013 +0100
> +++ b/agent/src/share/classes/sun/jvm/hotspot/types/basic/BasicTypeDataBase.java  Thu Feb 28 11:57:55 2013 +0800
> @@ -150,7 +150,7 @@
>      return VM.getVM().getOopSize();
>    }
> -  static HashMap typeToVtbl = new HashMap();
> +  private HashMap typeToVtbl = new HashMap();
>    private Address vtblForType(Type type) {
>      Address vtblAddr = (Address)typeToVtbl.get(type);
>  
>  
> After applying this patch, the problem I mentioned above disappeared.
>  
> Regards,
> Yunda
>  
>  
> 
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