From: Dave Hansen <dave@linux.vnet.ibm.com>
To: Christoph Lameter <cl@linux-foundation.org>
Cc: Russell King - ARM Linux <linux@arm.linux.org.uk>,
Minchan Kim <minchan.kim@gmail.com>,
KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>,
Milton Miller <miltonm@bga.com>,
linux-kernel@vger.kernel.org, linux-mm@kvack.org,
Andrew Morton <akpm@linux-foundation.org>,
Mel Gorman <mel@csn.ul.ie>, Johannes Weiner <hannes@cmpxchg.org>,
Kukjin Kim <kgene.kim@samsung.com>
Subject: Re: [PATCH] Tight check of pfn_valid on sparsemem - v4
Date: Fri, 30 Jul 2010 08:43:54 -0700 [thread overview]
Message-ID: <1280504634.16922.14449.camel@nimitz> (raw)
In-Reply-To: <alpine.DEB.2.00.1007300745180.9007@router.home>
On Fri, 2010-07-30 at 07:48 -0500, Christoph Lameter wrote:
> On Thu, 29 Jul 2010, Dave Hansen wrote:
>
> > SPARSEMEM_EXTREME would be a bit different. It's a 2-level lookup.
> > You'd have 16 "section roots", each representing 256MB of address space.
> > Each time we put memory under one of those roots, we'd fill in a
> > 512-section second-level table, which is designed to always fit into one
> > page. If you start at 256MB, you won't waste all those entries.
>
> That is certain a solution to the !MMU case and it would work very much
> like a page table. If you have an MMU then the vmemmap sparsemem
> configuration can take advantage of of that to avoid the 2 level lookup.
Yup, couldn't agree more, Christoph.
It wouldn't hurt to have several them available on ARM since the
architecture is so diverse.
-- Dave
WARNING: multiple messages have this Message-ID (diff)
From: Dave Hansen <dave@linux.vnet.ibm.com>
To: Christoph Lameter <cl@linux-foundation.org>
Cc: Russell King - ARM Linux <linux@arm.linux.org.uk>,
Minchan Kim <minchan.kim@gmail.com>,
KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>,
Milton Miller <miltonm@bga.com>,
linux-kernel@vger.kernel.org, linux-mm@kvack.org,
Andrew Morton <akpm@linux-foundation.org>,
Mel Gorman <mel@csn.ul.ie>, Johannes Weiner <hannes@cmpxchg.org>,
Kukjin Kim <kgene.kim@samsung.com>
Subject: Re: [PATCH] Tight check of pfn_valid on sparsemem - v4
Date: Fri, 30 Jul 2010 08:43:54 -0700 [thread overview]
Message-ID: <1280504634.16922.14449.camel@nimitz> (raw)
In-Reply-To: <alpine.DEB.2.00.1007300745180.9007@router.home>
On Fri, 2010-07-30 at 07:48 -0500, Christoph Lameter wrote:
> On Thu, 29 Jul 2010, Dave Hansen wrote:
>
> > SPARSEMEM_EXTREME would be a bit different. It's a 2-level lookup.
> > You'd have 16 "section roots", each representing 256MB of address space.
> > Each time we put memory under one of those roots, we'd fill in a
> > 512-section second-level table, which is designed to always fit into one
> > page. If you start at 256MB, you won't waste all those entries.
>
> That is certain a solution to the !MMU case and it would work very much
> like a page table. If you have an MMU then the vmemmap sparsemem
> configuration can take advantage of of that to avoid the 2 level lookup.
Yup, couldn't agree more, Christoph.
It wouldn't hurt to have several them available on ARM since the
architecture is so diverse.
-- Dave
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next prev parent reply other threads:[~2010-07-30 15:44 UTC|newest]
Thread overview: 72+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-07-26 15:46 [PATCH] Tight check of pfn_valid on sparsemem - v4 Minchan Kim
2010-07-26 15:46 ` Minchan Kim
2010-07-26 15:46 ` Minchan Kim
2010-07-26 16:40 ` Christoph Lameter
2010-07-26 16:40 ` Christoph Lameter
2010-07-26 16:40 ` Christoph Lameter
2010-07-26 22:47 ` Minchan Kim
2010-07-26 22:47 ` Minchan Kim
2010-07-26 22:47 ` Minchan Kim
2010-07-27 5:55 ` miltonm
2010-07-27 5:55 ` miltonm
2010-07-27 6:11 ` Minchan Kim
2010-07-27 8:12 ` Milton Miller
2010-07-27 8:12 ` Milton Miller
2010-07-27 8:13 ` KAMEZAWA Hiroyuki
2010-07-27 8:13 ` KAMEZAWA Hiroyuki
2010-07-27 10:01 ` Minchan Kim
2010-07-27 10:01 ` Minchan Kim
2010-07-27 14:34 ` Christoph Lameter
2010-07-27 14:34 ` Christoph Lameter
2010-07-27 22:33 ` Minchan Kim
2010-07-27 22:33 ` Minchan Kim
2010-07-28 15:14 ` Christoph Lameter
2010-07-28 15:14 ` Christoph Lameter
2010-07-28 15:56 ` Minchan Kim
2010-07-28 15:56 ` Minchan Kim
2010-07-28 17:02 ` Christoph Lameter
2010-07-28 17:02 ` Christoph Lameter
2010-07-28 22:57 ` Minchan Kim
2010-07-28 22:57 ` Minchan Kim
2010-07-29 15:46 ` Christoph Lameter
2010-07-29 15:46 ` Christoph Lameter
2010-07-29 16:18 ` Minchan Kim
2010-07-29 16:18 ` Minchan Kim
2010-07-29 16:47 ` Christoph Lameter
2010-07-29 16:47 ` Christoph Lameter
2010-07-29 17:03 ` Minchan Kim
2010-07-29 17:03 ` Minchan Kim
2010-07-29 17:30 ` Christoph Lameter
2010-07-29 17:30 ` Christoph Lameter
2010-07-29 18:33 ` Russell King - ARM Linux
2010-07-29 18:33 ` Russell King - ARM Linux
2010-07-29 19:55 ` Christoph Lameter
2010-07-29 19:55 ` Christoph Lameter
2010-07-29 21:13 ` Russell King - ARM Linux
2010-07-29 21:13 ` Russell King - ARM Linux
2010-07-29 20:55 ` Dave Hansen
2010-07-29 20:55 ` Dave Hansen
2010-07-29 22:14 ` Russell King - ARM Linux
2010-07-29 22:14 ` Russell King - ARM Linux
2010-07-29 22:28 ` Christoph Lameter
2010-07-29 22:28 ` Christoph Lameter
2010-07-30 0:38 ` Dave Hansen
2010-07-30 0:38 ` Dave Hansen
2010-07-30 9:43 ` Minchan Kim
2010-07-30 9:43 ` Minchan Kim
2010-07-30 12:48 ` Christoph Lameter
2010-07-30 12:48 ` Christoph Lameter
2010-07-30 15:43 ` Dave Hansen [this message]
2010-07-30 15:43 ` Dave Hansen
2010-07-31 15:30 ` Russell King - ARM Linux
2010-07-31 15:30 ` Russell King - ARM Linux
2010-08-02 15:48 ` Christoph Lameter
2010-08-02 15:48 ` Christoph Lameter
2010-07-30 9:32 ` Minchan Kim
2010-07-30 9:32 ` Minchan Kim
2010-07-31 10:38 ` Russell King - ARM Linux
2010-07-31 10:38 ` Russell King - ARM Linux
2010-08-11 15:31 ` Dave Hansen
2010-08-11 15:31 ` Dave Hansen
2010-07-27 9:56 ` Minchan Kim
2010-07-27 9:56 ` Minchan Kim
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