RFR: 2178143: VM crashes if the number of bound CPUs changed during runtime

Yumin Qi yumin.qi at oracle.com
Mon Mar 25 16:15:12 PDT 2013


It should be "AssumeMP".

/Yumin

On 3/25/2013 3:32 PM, Yumin Qi wrote:
> Hi,
>
>   New webrev to use "-XX:+AssumMP" flag. Also add warning to recommend 
> use this flag with "-XX:ParallelGCThreads" to remind user to avoid 
> running with only one GC thread. This is verified by Oleksandr with 
> the test case running on Linux which is not Zone configured.
>
>   Same link.
>
> Thanks
> Yumin
>
> On 3/20/2013 2:27 PM, Yumin Qi wrote:
>>
>> 2178143:  VM crashes if the number of bound CPUs changed during runtime.
>>
>> Situation: Customer first configure only one CPU online and turn 
>> others offline to run java application, after java program started, 
>> bring more CPUs back online. Since VM started on a single CPU, 
>> os::is_MP() will return false, but after more CPUs available, OS will 
>> schedule the app run on multiple CPUs, this caused SEGV in various 
>> places where data consistency was broken. The solution is supply a 
>> flag to assume it is running on MP, so lock is forced to be called.
>>
>> http://cr.openjdk.java.net/~minqi/2178143/
>>
>> Thanks
>> Yumin
>



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