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

[Vladimir Kozlov]

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
>