numa involved in instability and swap usage despite RAM free?

[Steve Kargl]

On Sun, Jun 24, 2018 at 12:03:29PM +0200, Alexander Leidinger wrote:
> 
> I don't have hard evidence, but there is enough "smell" to open up a  
> discussion...
> 
> Short:
> Can it be that enabling numa in the kernel is the reason why some  
> people see instability with zfs and usage of swap while a lot of free  
> RAM is available?

Interesting observation.  I do have NUMA in my kernel, and swap
seems to be used instead of recycling freeing inactive memory.
Top shows

Mem: 506M Active, 27G Inact, 98M Laundry, 2735M Wired, 1474M Buf, 1536M Free
Swap: 16G Total, 120M Used, 16G Free

Perhaps, I don't understand what is meant by inactive memory.  I
thought that this means memory is still available in the buffer
cache, but nothing is current using what is there.

--  
Steve