On Mon, 2006-12-04 at 11:30 -0800, Andrew Morton wrote:
I'd also like to pin down the situation with lumpy-reclaim versus
anti-fragmentation. No offence, but I would of course prefer to avoid
merging the anti-frag patches simply based on their stupendous size. It
seems to me that lumpy-reclaim is suitable for the e1000 problem, but
perhaps not for the hugetlbpage problem. Whereas anti-fragmentation adds
vastly more code, but can address both problems? Or something.
From my understanding they complement each other nicely. Without someform of anti fragmentation there is no guarantee lumpy reclaim will ever
free really high order pages. Although it might succeed nicely for the
network sized allocations we now have problems with.
- Andy, do you have any number on non largepage order allocations?
But anti fragmentation as per Mel's patches is not good enough to
provide largepage allocations since we would need to shoot down most of
the LRU to obtain such a large contiguous area. Lumpy reclaim however
can quickly achieve these sizes.