Re: [PATCH 4/4] zone_reclaim_mode is always 0 by default

Rik van Riel
2009-05-14T20:23:36Z

Christoph Lameter wrote:
> Not having zone reclaim on a NUMA system often means that per node
> allocations will fall back. Optimized node local allocations become very
> difficult for the page allocator. If the latency penalties are not
> significant then this may not matter. The larger the system, the larger
> the NUMA latencies become.
>
> One possibility would be to disable zone reclaim for low node numbers.
> Eanble it only if more than 4 nodes exist?

I suspect that patches 1/4 through 3/4 will cause the
system to behave better already, by only reclaiming
the easiest to reclaim pages from zone reclaim and
falling back after that - or am overlooking something?