Re: [PATCH] Use MPOL_INTERLEAVE for tmpfs files

From: Martin J. Bligh
Date: Tue Nov 02 2004 - 11:02:04 EST


> 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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