[PATCH 0/5] Sizing zones and holes in an architecture independent manner V7

[Andi Kleen]

> Ok, while true, I'm not sure how it affects performance. The only "real" 
> value affected by present_pages is the number of patches that are 
> allocated in batches to the per-cpu allocator.

It affects the low/high water marks in the VM zone balancer.

Especially for the 16MB DMA zone it can make a difference if you
account 4MB kernel in there or not.

-Andi