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From: Christoph Lameter <cl@linux.com>
To: Matthew Wilcox <matthew@wil.cx>
Cc: Pekka Enberg <penberg@kernel.org>,
	KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>,
	James Bottomley <James.Bottomley@hansenpartnership.com>,
	Michal Hocko <mhocko@suse.cz>,
	Andrew Morton <akpm@linux-foundation.org>,
	Hugh Dickins <hughd@google.com>,
	linux-mm@kvack.org, LKML <linux-kernel@vger.kernel.org>,
	linux-parisc@vger.kernel.org,
	David Rientjes <rientjes@google.com>, Ingo Molnar <mingo@elte.hu>,
	x86 maintainers <x86@kernel.org>, Mel Gorman <mel@csn.ul.ie>
Subject: Re: [PATCH v3] mm: make expand_downwards symmetrical to expand_upwards
Date: Wed, 20 Apr 2011 08:58:10 -0500 (CDT)	[thread overview]
Message-ID: <alpine.DEB.2.00.1104200855050.8634@router.home> (raw)
In-Reply-To: <20110420112020.GA31296@parisc-linux.org>

On Wed, 20 Apr 2011, Matthew Wilcox wrote:

> On Wed, Apr 20, 2011 at 10:34:23AM +0300, Pekka Enberg wrote:
> > That part makes me think the best option is to make parisc do
> > CONFIG_NUMA as well regardless of the historical intent was.
>
> But it's not just parisc.  It's six other architectures as well, some
> of which aren't even SMP.  Does !SMP && NUMA make any kind of sense?

Of course not.

> I think really, this is just a giant horrible misunderstanding on the part
> of the MM people.  There's no reason why an ARM chip with 16MB of memory
> at 0 and 16MB of memory at 1GB should be saddled with all the NUMA gunk.

DISCONTIG has fallen out of favor in the last years. SPARSEMEM has largely
replaced it. ARM uses that and does not suffer from these issue.

No one considered the issues of having a !NUMA configuration with
nodes (which DISCONTIG seems to create) when developing core code in the
last years. The implicit assumption has always been that page_to_nid(x)
etc is always zero on a !NUMA configuration.

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  parent reply	other threads:[~2011-04-20 13:58 UTC|newest]

Thread overview: 90+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2011-04-15 13:51 [PATCH] " Michal Hocko
2011-04-18  3:00 ` Hugh Dickins
2011-04-18 10:01   ` [PATCH v2] " Michal Hocko
2011-04-18 20:56     ` Andrew Morton
     [not found]       ` <20110419091022.GA21689@tiehlicka.suse.cz>
2011-04-19 11:09         ` [PATCH followup] mm: get rid of CONFIG_STACK_GROWSUP || CONFIG_IA64 Michal Hocko
2011-04-20  0:33           ` KOSAKI Motohiro
2011-04-20  6:59             ` Michal Hocko
2011-04-20  7:08               ` KOSAKI Motohiro
2011-04-26  7:59           ` Michal Hocko
2011-04-19 11:10       ` [PATCH v3] mm: make expand_downwards symmetrical to expand_upwards Michal Hocko
2011-04-19 15:46         ` James Bottomley
2011-04-19 16:06           ` [PATCH v3] mm: make expand_downwards symmetrical to John David Anglin
2011-04-19 16:59             ` James Bottomley
2011-04-19 16:07           ` [PATCH v3] mm: make expand_downwards symmetrical to expand_upwards James Bottomley
2011-04-19 17:05           ` Pekka Enberg
2011-04-19 17:11             ` James Bottomley
2011-04-19 17:15               ` Christoph Lameter
2011-04-19 17:48                 ` James Bottomley
2011-04-19 18:10                   ` Christoph Lameter
2011-04-19 18:20                     ` James Bottomley
2011-04-19 18:35                       ` Christoph Lameter
2011-04-19 19:49                         ` James Bottomley
2011-04-19 20:56                           ` Christoph Lameter
2011-04-19 21:21                             ` James Bottomley
2011-04-19 21:39                               ` Christoph Lameter
2011-04-19 21:48                                 ` James Bottomley
2011-04-19 21:58                                   ` Christoph Lameter
2011-04-20  1:23                                     ` KOSAKI Motohiro
2011-04-20  2:48                                       ` James Bottomley
2011-04-20  2:57                                         ` KOSAKI Motohiro
2011-04-20 13:50                                           ` Christoph Lameter
2011-04-21 13:32                                             ` Tejun Heo
2011-04-20  5:53                                       ` Pekka Enberg
2011-04-20  7:15                                         ` KOSAKI Motohiro
2011-04-20  7:34                                           ` Pekka Enberg
2011-04-20  8:40                                             ` KOSAKI Motohiro
2011-04-20 16:32                                               ` James Bottomley
2011-04-20 16:50                                                 ` Christoph Lameter
2011-04-20 18:09                                                   ` James Bottomley
2011-04-20 21:18                                                 ` David Rientjes
2011-04-20 22:15                                                   ` James Bottomley
2011-04-20 23:12                                                     ` David Rientjes
2011-04-21 13:16                                                       ` KOSAKI Motohiro
2011-04-21 16:37                                                         ` James Bottomley
2011-04-21 18:33                                                           ` Christoph Lameter
2011-04-21 18:45                                                             ` Dave Hansen
2011-04-22 18:19                                                               ` James Bottomley
2011-04-22 20:24                                                                 ` Dave Hansen
2011-04-22 20:35                                                                   ` James Bottomley
2011-04-22 21:33                                                               ` James Bottomley
2011-04-23 18:34                                                                 ` [PATCH] convert parisc to sparsemem (was Re: [PATCH v3] mm: make expand_downwards symmetrical to expand_upwards) James Bottomley
2011-04-24 16:27                                                                   ` John David Anglin
2011-04-26  0:32                                                                   ` KOSAKI Motohiro
2011-04-27 16:36                                                                   ` Dave Hansen
2011-04-21 20:05                                                             ` [PATCH v3] mm: make expand_downwards symmetrical to expand_upwards James Bottomley
2011-04-21 21:07                                                               ` Christoph Lameter
2011-04-21 21:22                                                                 ` James Bottomley
2011-04-21 19:33                                                         ` David Rientjes
2011-04-22  0:34                                                           ` KOSAKI Motohiro
2011-04-21 13:03                                                   ` KOSAKI Motohiro
2011-04-21 19:38                                                     ` David Rientjes
2011-04-21 20:02                                                       ` Christoph Lameter
2011-04-21 21:19                                                         ` David Rientjes
2011-04-21 21:24                                                           ` James Bottomley
2011-04-21 21:34                                                             ` David Rientjes
2011-04-21 21:49                                                               ` James Bottomley
2011-04-21 22:12                                                                 ` David Rientjes
2011-04-22  8:02                                                                   ` Pekka Enberg
2011-04-22 13:49                                                                     ` James Bottomley
2011-04-22 17:00                                                                       ` Pekka Enberg
2011-04-22 17:03                                                                         ` James Bottomley
2011-04-21 21:41                                                           ` [patch] mm: always set nodes with regular memory in N_NORMAL_MEMORY David Rientjes
2011-04-22  0:36                                                             ` KOSAKI Motohiro
2011-04-20 21:05                                               ` [PATCH v3] mm: make expand_downwards symmetrical to expand_upwards David Rientjes
2011-04-20 11:20                                             ` Matthew Wilcox
2011-04-20 11:28                                               ` Pekka Enberg
2011-04-20 14:15                                                 ` James Bottomley
2011-04-20 14:50                                                   ` Christoph Lameter
2011-04-20 15:02                                                     ` James Bottomley
2011-04-20 15:22                                                       ` Christoph Lameter
2011-04-20 19:25                                                         ` Matthew Wilcox
2011-04-20 21:42                                                         ` David Rientjes
2011-04-21 16:06                                                           ` James Bottomley
2011-04-21 22:19                                                             ` David Rientjes
2011-04-21 22:31                                                               ` James Bottomley
2011-04-20 13:58                                               ` Christoph Lameter [this message]
2011-04-20 21:34                                               ` David Rientjes
2011-04-20 14:07                                             ` Christoph Lameter
2011-04-20  2:33                                     ` James Bottomley
2011-04-19 17:12             ` Christoph Lameter

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