From: Tejun Heo <tj@kernel.org>
To: Christoph Lameter <cl@linux.com>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>,
James Bottomley <James.Bottomley@HansenPartnership.com>,
Pekka Enberg <penberg@kernel.org>, 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>
Subject: Re: [PATCH v3] mm: make expand_downwards symmetrical to expand_upwards
Date: Thu, 21 Apr 2011 15:32:48 +0200 [thread overview]
Message-ID: <20110421133248.GD31724@htj.dyndns.org> (raw)
In-Reply-To: <alpine.DEB.2.00.1104200847240.8634@router.home>
Hey,
On Wed, Apr 20, 2011 at 08:50:15AM -0500, Christoph Lameter wrote:
> Tejon was working on getting rid of DISCONTIG. SPARSEMEM is the favored
> alternative today. So we could potentially change the arches to use SPARSE
> configs in the !NUMA case.
Well, the thing is that sparsemem w/ vmemmap is definitely better than
discontigmem on x86-64; however, on x86-32, vmemmap can't be used due
to address space shortage and there are some minor disadvantages to
sparsemem compared to discontigmem.
IIRC, the biggest was losing a bit of granuality in memsections and
possibly wasting slightly more memory on the page array. Both didn't
seem critical to me but given that the actual amount of code needed
for discontigmem in arch code was fairly small (although the amount of
added complexity for auditing/testing can be much higher) I didn't
feel sure about dropping discontigmem and thus the patchset to drop
discontigmem was posted as RFC, to which nobody commented.
http://thread.gmane.org/gmane.linux.kernel/1121321
What do you guys think?
Thanks.
--
tejun
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next prev parent reply other threads:[~2011-04-21 13:33 UTC|newest]
Thread overview: 90+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-04-15 13:51 [PATCH] mm: make expand_downwards symmetrical to expand_upwards 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 [this message]
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
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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