JVM/TI code review request (XS and M) (7182152)

[Daniel D. Daugherty]

On 2/4/13 12:21 PM, serguei.spitsyn at oracle.com wrote:
> Dan,
>
>
> The fixes look good for all 3 HS versions (modulo discussions with 
> Coleen and Karen).
> Great discovery, thank you for doing this!

Thanks Serguei!

I'm working on addressing Coleen's and Karen's comments
and will be rolling out three new webrevs...

Dan


>
> Thanks,
> Serguei
>
>
>
> On 2/1/13 11:55 AM, Daniel D. Daugherty wrote:
>> Greetings,
>>
>> I have a fix for the following JVM/TI bug:
>>
>>     7182152 Instrumentation hot swap test incorrect monitor count
>>     http://bugs.sun.com/bugdatabase/view_bug.do?bug_id=7182152
>>     https://jbs.oracle.com/bugs/browse/JDK-7182152
>>
>> The fix for the bug in the product code is one line:
>>
>> src/share/vm/oops/klassVtable.cpp:
>>
>> @@ -992,18 +1020,50 @@
>>            // RC_TRACE macro has an embedded ResourceMark
>>            RC_TRACE(0x00200000, ("itable method update: %s(%s)",
>>              new_method->name()->as_C_string(),
>>              new_method->signature()->as_C_string()));
>>          }
>> -        break;
>> +        // cannot 'break' here; see for-loop comment above.
>>        }
>>        ime++;
>>      }
>>    }
>>  }
>>
>> and is applicable to JDK7u10/HSX-23.6 and JDK7u14/HSX-24. Coleen
>> already fixed the bug as part of the Perm Gen Removal (PGR) project
>> in HSX-25. Yes, we found a 1-line bug fix buried in the monster PGR
>> changeset. Many thanks to Coleen for her help in this bug hunt!
>>
>> The rest of the code in the webrevs are:
>>
>> - additional JVM/TI tracing code backported from Coleen's PGR changeset
>> - additional JVM/TI tracing code added by me and forward ported to 
>> HSX-25
>> - a new -XX:TraceRedefineClasses=16384 flag value for finding these
>>   elusive old or obsolete methods
>> - exposure of some printing code to the PRODUCT build so that the new
>>   tracing is available in a PRODUCT build
>>
>> You might be wondering why the new tracing code is exposed in a PRODUCT
>> build. Well, it appears that more and more PRODUCT bits deployments are
>> using JVM/TI RedefineClasses() and/or RetransformClasses() at run-time
>> to instrument their systems. This bug (7182152) was only intermittently
>> reproducible in the WLS environment in which it occurred so I made the
>> tracing available in a PRODUCT build to assist in the hunt.
>>
>> Raj from the WLS team has also verified that the HSX-23.6 version of
>> fix resolves the issue in his environment. Thanks Raj!
>>
>> Here are the URLs for the three webrevs:
>>
>> http://cr.openjdk.java.net/~dcubed/7182152-webrev/0-hsx23.6/
>> http://cr.openjdk.java.net/~dcubed/7182152-webrev/0-hsx24/
>> http://cr.openjdk.java.net/~dcubed/7182152-webrev/0-hsx25/
>>
>> I have run the following test suites from the JPDA stack on the
>> JDK7u10/HSX-23.6 version of the fix with -XX:TraceRedefineClasses=16384
>> specified:
>>
>>     sdk-jdi
>>     sdk-jdi_closed
>>     sdk-jli
>>     vm-heapdump
>>     vm-hprof
>>     vm-jdb
>>     vm-jdi
>>     vm-jdwp
>>     vm-jvmti
>>     vm-sajdi
>>
>> The tested configs are:
>>
>>     {Solaris-X86, WinXP}
>>       X {Client VM, Server VM}
>>       X {-Xmixed, -Xcomp}
>>       X {product, fastdebug}
>>
>> With the 1-liner fix in place, the new tracing code does not find any
>> instances of this failure mode in any of the above test suites. Without
>> the the 1-liner fix in place, the new tracing code finds one instance
>> of this failure mode in the above test suites:
>>
>>     test/java/lang/instrument/IsModifiableClassAgent.java
>>
>> There are two new tests that will be pushed to the JDK repos using
>> a different bug ID (not yet filed):
>>
>>     test/com/sun/jdi/RedefineAbstractClass.sh
>> test/java/lang/instrument/RedefineSubclassWithTwoInterfaces.sh
>>
>> There will be a separate review request for the new tests.
>>
>> I'm currently running the JPDA stack of tests on the JDK7u14/HSX-24
>> and JDK8-B75/HSX-25 versions of the fix. That testing will likely
>> take all weekend to complete.
>>
>> Thanks, in advance, for any comments and/or suggestions.
>>
>> Dan
>>
>