From mboxrd@z Thu Jan  1 00:00:00 1970
Return-Path: <linux-kernel-owner+willy=40w.ods.org-S1751159AbWDQQ5W@vger.kernel.org>
Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand
	id S1751159AbWDQQ5W (ORCPT <rfc822;willy@w.ods.org>);
	Mon, 17 Apr 2006 12:57:22 -0400
Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751154AbWDQQ5W
	(ORCPT <rfc822;linux-kernel-outgoing>);
	Mon, 17 Apr 2006 12:57:22 -0400
Received: from omx1-ext.sgi.com ([192.48.179.11]:7296 "EHLO
	omx1.americas.sgi.com") by vger.kernel.org with ESMTP
	id S1751124AbWDQQ5V (ORCPT <rfc822;linux-kernel@vger.kernel.org>);
	Mon, 17 Apr 2006 12:57:21 -0400
Date: Mon, 17 Apr 2006 09:55:02 -0700 (PDT)
From: Christoph Lameter <clameter@sgi.com>
To: kiran@scalex86.org
cc: Nick Piggin <nickpiggin@yahoo.com.au>,
       Steven Rostedt <rostedt@goodmis.org>,
       LKML <linux-kernel@vger.kernel.org>, Andrew Morton <akpm@osdl.org>,
       Linus Torvalds <torvalds@osdl.org>, Ingo Molnar <mingo@elte.hu>,
       Thomas Gleixner <tglx@linutronix.de>, Andi Kleen <ak@suse.de>,
       Martin Mares <mj@atrey.karlin.mff.cuni.cz>, bjornw@axis.com,
       schwidefsky@de.ibm.com, benedict.gaster@superh.com, lethal@linux-sh.org,
       Chris Zankel <chris@zankel.net>, Marc Gauthier <marc@tensilica.com>,
       Joe Taylor <joe@tensilica.com>,
       David Mosberger-Tang <davidm@hpl.hp.com>, rth@twiddle.net,
       spyro@f2s.com, starvik@axis.com, tony.luck@intel.com,
       linux-ia64@vger.kernel.org, ralf@linux-mips.org,
       linux-mips@linux-mips.org, grundler@parisc-linux.org,
       parisc-linux@parisc-linux.org, linuxppc-dev@ozlabs.org,
       paulus@samba.org, linux390@de.ibm.com, davem@davemloft.net
Subject: Re: [PATCH 00/05] robust per_cpu allocation for modules
In-Reply-To: <4440855A.7040203@yahoo.com.au>
Message-ID: <Pine.LNX.4.64.0604170953390.29732@schroedinger.engr.sgi.com>
References: <1145049535.1336.128.camel@localhost.localdomain>
 <4440855A.7040203@yahoo.com.au>
MIME-Version: 1.0
Content-Type: TEXT/PLAIN; charset=US-ASCII
Sender: linux-kernel-owner@vger.kernel.org
X-Mailing-List: linux-kernel@vger.kernel.org

On Sat, 15 Apr 2006, Nick Piggin wrote:

> If I'm following you correctly, this adds another dependent load
> to a per-CPU data access, and from memory that isn't node-affine.

I am also concerned about that. Kiran has a patch to avoid allocpercpu
having to go through one level of indirection that I guess would no 
longer work with this scheme.
 
> If so, I think people with SMP and NUMA kernels would care more
> about performance and scalability than the few k of memory this
> saves.

Right.