Date: Wed, 20 Jan 2010 12:12:55 -0600 (CST)
From: Christoph Lameter <cl@linux-foundation.org>
To: Mel Gorman <mel@csn.ul.ie>
cc: David Rientjes <rientjes@google.com>,
       Andrea Arcangeli <aarcange@redhat.com>, Adam Litke <agl@us.ibm.com>,
       Avi Kivity <avi@redhat.com>, linux-kernel@vger.kernel.org,
       linux-mm@kvack.org
Subject: Re: [PATCH 5/7] Add /proc trigger for memory compaction
In-Reply-To: <20100120094813.GC5154@csn.ul.ie>
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On Wed, 20 Jan 2010, Mel Gorman wrote:

> True, although the per-node structures are only available on NUMA making
> it necessary to have two interfaces. The per-node one is handy enough
> because it would be just
>
> /sys/devices/system/node/nodeX/compact_node
> 	When written to, this node is compacted by the writing process
>
> But there does not appear to be a "good" way of having a non-NUMA
> interface. /sys/devices/system/node does not exist .... Does anyone
> remember why !NUMA does not have a /sys/devices/system/node/node0? Is
> there a good reason or was there just no point?

We could create a fake node0 for the !NUMA case I guess? Dont see a major
reason why not to do it aside from scripts that may check for the presence
of the file to switch to a "NUMA" mode.

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