review (XXS): 7151089: PS NUMA: NUMA allocator should not attempt to free pages when using SHM large pages

[Vladimir Kozlov]

This looks good.

Thanks,
Vladimir

Igor Veresov wrote:
>   Sure: http://cr.openjdk.java.net/~iveresov/7151089/webrev.01/
> 
> I also decided to use the check of UseSHM explicitly to make the idea 
> clearer. 
> 
> Thanks!
> igor
> 
> On Monday, March 5, 2012 at 7:12 PM, Vladimir Kozlov wrote:
> 
>> Add comment explaining the condition.
>>
>> Vladimir
>>
>> Igor Veresov wrote:
>>> We already turn adaptive resizing off (UseAdaptiveNUMAChunkSizing and
>>> UseAdaptiveSizePolicy) when using SHM-based large pages because these
>>> don't support uncommiting. However that is not enough - during the
>>> initialization we still do it once, which on linux leads to mmaping over
>>> the eden portion of the SHM segment. By doing this we loose large pages
>>> support and also increase memory requirements.
>>>
>>> The solution is to avoid attempting to free memory for SHM-based setups.
>>>
>>> Webrev: http://cr.openjdk.java.net/~iveresov/7151089/webrev.00/
>>>
>>> igor
>