From: Dave Hansen <dave@linux.vnet.ibm.com>
To: James Bottomley <James.Bottomley@HansenPartnership.com>
Cc: Christoph Lameter <cl@linux.com>,
KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>,
David Rientjes <rientjes@google.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, Ingo Molnar <mingo@elte.hu>,
x86 maintainers <x86@kernel.org>, Tejun Heo <tj@kernel.org>,
Mel Gorman <mel@csn.ul.ie>
Subject: Re: [PATCH v3] mm: make expand_downwards symmetrical to expand_upwards
Date: Fri, 22 Apr 2011 13:24:48 -0700 [thread overview]
Message-ID: <1303503888.9308.6661.camel@nimitz> (raw)
In-Reply-To: <1303496357.2590.38.camel@mulgrave.site>
On Fri, 2011-04-22 at 13:19 -0500, James Bottomley wrote:
> I looked at converting parisc to sparsemem and there's one problem that
> none of these cover. How do you set up bootmem? If I look at the
> examples, they all seem to have enough memory in the first range to
> allocate from, so there's no problem. On parisc, with discontigmem, we
> set up all of our ranges as bootmem (we can do this because we
> effectively have one node per range). Obviously, since sparsemem has a
> single bitmap for all of the bootmem, we can no longer allocate all of
> our memory to it (well, without exploding because some of our gaps are
> gigabytes big). How does everyone cope with this (do you search for
> your largest range and use that as bootmem or something)?
Sparsemem is purely post-bootmem. It doesn't deal with sparse
bootmem. :(
That said, I'm not sure you're in trouble. One bit of bitmap covers 4k
(with 4k pages of course) of memory, one byte covers 32k, and A 32MB
bitmap can cover 1TB of address space. It explodes, but I think it's
manageable. It hasn't been a problem enough up to this point to go fix
it.
-- Dave
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next prev parent reply other threads:[~2011-04-22 20:24 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
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 [this message]
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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