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

From: Rik van Riel
Date: Thu May 14 2009 - 16:23:38 EST


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?
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