True, it's all a bit more complicated. Perhaps he should tune things like
dirty_ratio and other dirty_* settings instead.
But a large free list is useful to handle sudden memory pressure situations
well without destroying latency. So if you have a spiky load having a bigger
free list seems like a good idea to me. If you make sudden huge allocations
then a bigger free list won't help much, what you want then is little dirty
data hanging around.