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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