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From: Jeremy Fitzhardinge <jeremy@goop.org>
To: Christoph Lameter <clameter@sgi.com>
Cc: Rusty Russell <rusty@rustcorp.com.au>,
	akpm@linux-foundation.org, linux-kernel@vger.kernel.org,
	Andi Kleen <ak@suse.de>
Subject: Re: [patch 05/14] percpu: Use a Kconfig variable to configure arch specific percpu setup
Date: Wed, 28 Nov 2007 17:54:55 -0800	[thread overview]
Message-ID: <474E1BEF.7010303@goop.org> (raw)
In-Reply-To: <Pine.LNX.4.64.0711281745470.20042@schroedinger.engr.sgi.com>

Christoph Lameter wrote:
> The percpu areas need to be allocated in a NUMA aware fashion. Otherwise 
> you use distant memory for the most performance sensitive areas. The NUMA 
> subsystem must be so far up that these allocations can be performed in the 
> right way. And this means at least you need to know on which node each 
> processor is located. That is what the PDA is currently used for and i386 
> has no other way of doing that. I think we could use an array [NR_CPUS] 
> for this one but we want to avoid these arrays because NR_CPUS may get 
> very big.
>   

Oh, you mean there needs to be some percpu data mechanism operating in
order to do numa-aware allocations, which would be necessary to allocate
the percpu memory itself?

I can see how that would be awkward.

    J


  reply	other threads:[~2007-11-29  1:55 UTC|newest]

Thread overview: 58+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2007-11-27  0:14 [patch 00/14] Per cpu code simplification Christoph Lameter
2007-11-27  0:14 ` [patch 01/14] Modules: Handle symbols that have a zero value Christoph Lameter
2007-11-27  0:14 ` [patch 02/14] Modules: Include sections.h to avoid defining linker variables explicitly Christoph Lameter
2007-11-27  0:14 ` [patch 03/14] Modules: Fold percpu_modcopy into module.c and get rid of the macro from hell Christoph Lameter
2007-11-27  0:14 ` [patch 04/14] ia64: Remove the __SMALL_ADDR_AREA attribute for per cpu access Christoph Lameter
2007-11-27  5:20   ` David Mosberger-Tang
2007-11-27 18:15     ` Christoph Lameter
2007-11-27 21:10       ` David Mosberger-Tang
2007-11-27 21:18         ` Christoph Lameter
2007-11-27 21:27           ` David Mosberger-Tang
2007-11-27 22:02             ` Christoph Lameter
2007-11-27  9:30   ` Andreas Schwab
2007-11-27 18:17     ` Christoph Lameter
2007-11-27 21:24       ` Andreas Schwab
2007-11-27 21:38         ` Christoph Lameter
2007-11-27 22:14           ` Adrian Bunk
2007-11-27  0:14 ` [patch 05/14] percpu: Use a Kconfig variable to configure arch specific percpu setup Christoph Lameter
2007-11-27  4:30   ` Rusty Russell
2007-11-27 18:14     ` Christoph Lameter
2007-11-28  1:36       ` Rusty Russell
2007-11-28 18:51         ` Christoph Lameter
2007-11-28 23:17           ` Rusty Russell
2007-11-28 23:36             ` Christoph Lameter
2007-11-30  2:23               ` Rusty Russell
2007-11-28 23:45             ` Jeremy Fitzhardinge
2007-11-29  0:11               ` Christoph Lameter
2007-11-29  1:18                 ` Andi Kleen
2007-11-29  1:27                   ` Christoph Lameter
2007-11-29  1:30                 ` Jeremy Fitzhardinge
2007-11-29  1:32                   ` Andi Kleen
2007-11-29  1:35                   ` Christoph Lameter
2007-11-29  1:42                     ` Jeremy Fitzhardinge
2007-11-29  1:48                       ` Christoph Lameter
2007-11-29  1:54                         ` Jeremy Fitzhardinge [this message]
2007-11-29  2:06                       ` Christoph Lameter
2007-11-29  5:29                         ` Jeremy Fitzhardinge
2007-11-29  6:08                           ` Christoph Lameter
2007-11-29  6:10                           ` Christoph Lameter
2007-11-27 23:40   ` Randy Dunlap
2007-11-28  0:03     ` Christoph Lameter
2007-11-28  0:05       ` Randy Dunlap
2007-11-27  0:14 ` [patch 06/14] percpu: Move arch XX_PER_CPU_XX definitions into linux/percpu.h Christoph Lameter
2007-11-27  0:14 ` [patch 07/14] percpu: Make the asm-generic/percpu.h more generic Christoph Lameter
2007-11-27  0:14 ` [patch 08/14] x86_32: Use generic percpu.h Christoph Lameter
2007-11-27  0:14 ` [patch 09/14] x86_64: Use generic percpu Christoph Lameter
2007-11-27  0:14 ` [patch 10/14] s390: " Christoph Lameter
2007-11-27  0:14 ` [patch 11/14] Powerpc: Use generic per cpu Christoph Lameter
2007-11-27  7:41   ` Kumar Gala
2007-11-27 18:16     ` Christoph Lameter
2007-11-27 20:58       ` Paul Mackerras
2007-11-27 21:13         ` Christoph Lameter
2007-11-28  2:35           ` Paul Mackerras
2007-11-28 18:54             ` Christoph Lameter
2007-12-02 20:55               ` Benjamin Herrenschmidt
2007-11-27  0:14 ` [patch 12/14] Sparc64: Use generic percpu Christoph Lameter
2007-11-27  0:14 ` [patch 13/14] ia64: " Christoph Lameter
2007-11-27  1:37   ` Christoph Lameter
2007-11-27  0:14 ` [patch 14/14] x86: Unify percpu.h Christoph Lameter

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