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From: Christoph Lameter <cl@linux.com>
To: James Bottomley <James.Bottomley@HansenPartnership.com>
Cc: linux-arch@vger.kernel.org, linux-mm@vger.kernel.org,
	"hugh.dickins@tiscali.co.uk" <hugh.dickins@tiscali.co.uk>,
	Parisc List <linux-parisc@vger.kernel.org>
Subject: Re: slub: fix panic with DISCONTIGMEM
Date: Tue, 19 Apr 2011 16:38:29 -0500 (CDT)	[thread overview]
Message-ID: <alpine.DEB.2.00.1104191633250.23077@router.home> (raw)
In-Reply-To: <1303248576.11237.23.camel@mulgrave.site>

On Tue, 19 Apr 2011, James Bottomley wrote:

> Slub makes assumptions about page_to_nid() which are violated by
> DISCONTIGMEM and !NUMA.  This violation results in a panic because

Fix this by stating correctly by saying "The kernel makes assumptions in
various subsystems ..."

> page_to_nid() can be non-zero for pages in the discontiguous ranges and
> this leads to a null return by get_node().  The assertion by the
> maintainer is that DISCONTIGMEM should only be allowed when NUMA is also
> defined.  However, at least six architectures: alpha, ia64, m32r, m68k,

That is not what I said. DISCONTIG support needs to be fixed so that the
core subsystems using page_to_nid() will operate correctly with a !NUMA
discontig configuration. Core will expect page_to_nid() to only return 0
on !NUMA.

  parent reply	other threads:[~2011-04-19 21:38 UTC|newest]

Thread overview: 12+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2011-04-19 21:29 slub: fix panic with DISCONTIGMEM James Bottomley
2011-04-19 21:29 ` James Bottomley
2011-04-19 21:38 ` Christoph Lameter [this message]
2011-04-19 21:52   ` James Bottomley
2011-04-19 21:52     ` James Bottomley
2011-04-19 22:04     ` Christoph Lameter
2011-04-19 22:04       ` Christoph Lameter
2011-04-20  7:48 ` Geert Uytterhoeven
2011-04-20  7:48   ` Geert Uytterhoeven
2011-04-20 13:54   ` Christoph Lameter
2011-04-23  1:27   ` Michael Schmitz
2011-04-23  1:27     ` Michael Schmitz

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