RFR(S): 8168305 GC.class_stats should not require -XX:+UnlockDiagnosticVMOptions

[Ioi Lam]

Looks good.

Thanks
- Ioi

On 10/27/16 2:41 AM, Marcus Larsson wrote:
> Hi Staffan,
>
>
> On 2016-10-27 10:36, Staffan Larsen wrote:
>> All,
>>
>> Please review this small patch to remove the requirement 
>> -XX:+UnlockDiagnosticVMOptions when running the GC.class_stats 
>> diagnostic command. Diagnostic commands are used for diagnosing 
>> problems and should not require restarting the JVM with a different 
>> command line flag if this can be avoided.
>>
>> While fixing this I also noticed that VM.print_touched_methods said 
>> it required -XX:+UnlockDiagnosticVMOptions, while what it really 
>> required was -XX:+LogTouchedMethods (which in turn requires 
>> -XX:+UnlockDiagnosticVMOptions) so I changed the error message here. 
>> In this case I think it is ok to require a special command line flag 
>> since collecting the information comes with an overhead.
>>
>> I have verified the fix manually and by running these tests: 
>> hotspot/test/runtime/CommandLine/PrintTouchedMethods.java 
>> hotspot/test/serviceability/sa/TestInstanceKlassSize.java 
>> hotspot/test/serviceability/sa/TestInstanceKlassSizeForInterface.java
>>
>> bug: https://bugs.openjdk.java.net/browse/JDK-8168305
>> webrev: http://cr.openjdk.java.net/~sla/8168305/webrev.01/
>
> The command description still mentions the flag, see
> src/share/vm/services/diagnosticCommand.hpp:389
>
> Apart from that this looks good to me!
>
> Thanks,
> Marcus
>
>>
>> Thanks,
>> /Staffan
>