Re: Default zone_reclaim_mode = 1 on NUMA kernel is bad forfile/email/webservers

[Christoph Lameter]

On Tue, 21 Sep 2010, Mel Gorman wrote:

> > However there's still another question, why is this problem happening at
> > all for us? I know almost nothing about NUMA, but from other posts, it
> > sounds like the problem is the memory allocations are all happening on
> > one node?
>
> Yes.

This could be a screwy hardware issue as pointed out before. Certain
controllers restrict the memory that I/O can be done to also (32 bit
controller only able to do I/O to lower 2G?, controller on a PCI bus that
is local only to a particular node) which would make balancing
the file cache difficult.
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