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From: Christoph Lameter <clameter@sgi.com>
To: Andrew Morton <akpm@linux-foundation.org>
Cc: Andi Kleen <ak@suse.de>,
	KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>,
	LKML <linux-kernel@vger.kernel.org>, GOTO <y-goto@jp.fujitsu.com>,
	Christoph Lameter <clameter@engr.sgi.com>
Subject: Re: [2.6.20][PATCH] fix mempolicy error check on a system with memory-less-node
Date: Thu, 8 Feb 2007 11:09:40 -0800 (PST)	[thread overview]
Message-ID: <Pine.LNX.4.64.0702081106460.11045@schroedinger.engr.sgi.com> (raw)
In-Reply-To: <20070207094344.0efdde10.akpm@linux-foundation.org>

On Wed, 7 Feb 2007, Andrew Morton wrote:

> > > 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,
> > 
> > It doesn't.
> 
> Fix it?

Why? It is a bad idea.
 
> > > and to 
> > > accurately present the machine's topology to the user without us having to
> > > go adding falsehoods like this?
> > 
> > a node is a piece of memory. Without memory it doesn't make sense.
> 
> Who said?  I can pick up a piece of circuitry which has four CPUs and no
> RAM, wave it about then stick it in a computer.  The kernel is just wrong,
> surely?

Surely your computer has some memory so attach it to that memory (which 
in a NUMA system would be one or the other node).

Cpu only "nodes" would mean that all memory would be off node. Meaning 
whatever interconnect one has would be heavily used. Operating system and 
application performance will suffer.



  parent reply	other threads:[~2007-02-08 19:09 UTC|newest]

Thread overview: 26+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2007-02-06 11:23 KAMEZAWA Hiroyuki
2007-02-06 17:26 ` Christoph Lameter
2007-02-07  1:14   ` KAMEZAWA Hiroyuki
2007-02-07  8:04     ` Christoph Lameter
2007-02-07  8:36       ` KAMEZAWA Hiroyuki
2007-02-08 11:49         ` Bob Picco
2007-02-07 10:20       ` Andi Kleen
2007-02-07 10:20 ` Andi Kleen
2007-02-07 10:07   ` KAMEZAWA Hiroyuki
2007-02-07 10:19     ` Andi Kleen
2007-02-07 10:37       ` KAMEZAWA Hiroyuki
2007-02-07 10:41         ` Andi Kleen
2007-02-07 10:49           ` KAMEZAWA Hiroyuki
2007-02-07 11:32             ` Andi Kleen
2007-02-07 12:27               ` KAMEZAWA Hiroyuki
2007-02-07 14:05     ` Christoph Lameter
2007-02-07 15:28       ` KAMEZAWA Hiroyuki
2007-02-07 14:03   ` Christoph Lameter
2007-02-07 16:23   ` Andrew Morton
2007-02-07 16:50     ` Andi Kleen
2007-02-07 17:43       ` Andrew Morton
2007-02-07 18:15         ` [PATCH] FS : Speedup rw_verify_area() Eric Dumazet
2007-02-08  0:37         ` [2.6.20][PATCH] fix mempolicy error check on a system with memory-less-node KAMEZAWA Hiroyuki
2007-02-08 19:09         ` Christoph Lameter [this message]
2007-02-08 19:26           ` Andrew Morton
2007-02-08 19:35             ` Christoph Lameter

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