Re: [2.6.20][PATCH] fix mempolicy error check on a system with memory-less-node

Andrew Morton
2007-02-07T16:23:42Z

On 07 Feb 2007 11:20:06 +0100 Andi Kleen <ak@suse.de> wrote:

> KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> writes:
>
> > current mempolicy just checks whether a node is online or not.
> > If there is memory-less-node, mempolicy's target node can be
> > invalid.
> > This patch adds a check whether a node has memory or not.
>
> IMHO there shouldn't be any memory less nodes. The architecture code
> should not create them. The CPU should be assigned to a nearby node instead.

umm, why?

A node which has CPUs and no memory is obviously physically possible and
isn't a completely insane thing for a user to do. I'd have thought that
the kernel should be able to cleanly and clearly handle it, and to
accurately present the machine's topology to the user without us having to
go adding falsehoods like this?

> At least x86-64 ensures that.
>
> -Andi