RFR(S): 8198794: Hotspot crash on Cassandra 3.11.1 startup with libnuma 2.0.3

[David Holmes]

On 14/03/2018 4:35 AM, Gustavo Romero wrote:
> Hi,
> 
> On 03/13/2018 11:50 AM, Hohensee, Paul wrote:
>> Looks good to me.
> 
> Thanks for reviewing it.
> 
> 
> @David, do you mind to review that small change (maybe it
> should be marked as XS actually...) regarding libnuma
> since you reviewed the previous ones?
> 
> bug   : https://bugs.openjdk.java.net/browse/JDK-8198794
> webrev: http://cr.openjdk.java.net/~gromero/8198794/v1/

Seems okay. Couple of grammar nits with the mega comment:

// it can exist nodes

it -> there

// are besides that non-contiguous.

"are besides that" -> "may be"

Thanks,
David

> 
> Regards,
> Gustavo
> 
>> Paul
>>
>> On 3/12/18, 6:13 PM, "Gustavo Romero" <gromero at linux.vnet.ibm.com> 
>> wrote:
>>
>>      Hi.
>>      Paul, I just saw today your bug on JBS...
>>      https://bugs.openjdk.java.net/browse/JDK-8198794
>>      Thanks for reporting and debugging it.
>>      It looks like the issue boils down to the fact that although
>>      'numa_all_nodes_ptr' was introduced with libnuma API v2, 
>> 'numa_nodes_ptr'
>>      was only introduced later on libnuma v2.0.9, so it's not present 
>> in libnuma
>>      2.0.3 which dates back to Jun 2009 [1]. I agree with your initial 
>> patch
>>      that a reasonable way to address it for archs like x86_64 is to use
>>      'numa_all_nodes_ptr' as a surrogate for 'numa_nodes_ptr' (PowerPC 
>> needs
>>      'numa_nodes_ptr' anyway and will have to stick with libnuma 2.0.9 
>> and above
>>      because it's not unusual to have non-configured nodes on PPC64 
>> and nodes
>>      can be non-contiguous as well).
>>      I just think it's better to handle it inside 
>> isnode_in_existing_nodes()
>>      interface, which is where such a information is needed in the 
>> end. In that
>>      sense, if you agree could you please check if the following 
>> webrev fixes
>>      the issue for you? It must also apply ok for jdk8u:
>>      bug   : https://bugs.openjdk.java.net/browse/JDK-8198794
>>      webrev: http://cr.openjdk.java.net/~gromero/8198794/v1/
>>      If it does solve your issue, I will kindly ask for another Reviewer.
>>      Thank you.
>>      Best regards,
>>      Gustavo
>>      [1] 
>> http://cr.openjdk.java.net/~gromero/misc/numa_all_nodes_ptr_VS_numa_nodes_ptr.txt 
>>
>>
>