Date: Tue, 02 Nov 2004 07:46:59 -0800
From: "Martin J. Bligh" <mbligh@aracnet.com>
To: Brent Casavant <bcasavan@sgi.com>, linux-kernel@vger.kernel.org,
       linux-mm@kvack.org
cc: hugh@veritas.com, ak@suse.de
Subject: Re: [PATCH] Use MPOL_INTERLEAVE for tmpfs files
Message-ID: <14340000.1099410418@[10.10.2.4]>
In-Reply-To: <Pine.SGI.4.58.0411011901540.77038@kzerza.americas.sgi.com>
References: <Pine.SGI.4.58.0411011901540.77038@kzerza.americas.sgi.com>
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> This patch causes memory allocation for tmpfs files to be distributed
> evenly across NUMA machines.  In most circumstances today, tmpfs files
> will be allocated on the same node as the task writing to the file.
> In many cases, particularly when large files are created, or a large
> number of files are created by a single task, this leads to a severe
> imbalance in free memory amongst nodes.  This patch corrects that
> situation.

Yeah, but it also ruins your locality of reference (in a NUMA sense). 
Not convinced that's a good idea. You're guaranteeing universally consistent
worse-case performance for everyone. And you're only looking at a situation
where there's one allocator on the system, and that's imbalanced.

You WANT your data to be local. That's the whole idea.

M.
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