Re: amd64 questions

From: Hugo Mills <hugo-lkml@carfax.org.uk>
To: Paul Wagland <paul@wagland.net>
Cc: Hugo Mills <hugo-lkml@carfax.org.uk>,
	"J. Ryan Earl" <heretic@clanhk.org>,
	linux-kernel@vger.kernel.org, Andi Kleen <ak@muc.de>
Subject: Re: amd64 questions
Date: Sun, 11 Apr 2004 12:45:57 +0100	[thread overview]
Message-ID: <20040411114557.GB22258@selene> (raw)
In-Reply-To: <A716F1DA-8BAC-11D8-A41D-000A95CD704C@wagland.net>

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On Sun, Apr 11, 2004 at 01:37:46PM +0200, Paul Wagland wrote:
> 
> On Apr 10, 2004, at 21:02, Hugo Mills wrote:
> 
> >On Sat, Apr 10, 2004 at 08:49:04PM +0200, Andi Kleen wrote:
> >>>line either?  Or we can if we use AMD64 [DM] libraries with a AMD64
> >>>kernel?  DM = Device Mapper right?
> >>
> >>You can't use Device Mapper with 32bit user tools on a 64bit kernel
> >>right now.
> >
> >   Well, you can, because that's what I'm doing on this machine. Joe
> >Thornber posted a patch[1] here a few weeks ago which fixes the
> >problem in a "sealing-wax-and-string" kind of way. It Works For
> >Me(tm), which is about all you can say about it -- it's not the
> >prettiest piece of code, even to my non-kernel eyes. :)
> 
> Ah, yes, but you missed the bit slightly later in the thread where Andi 
> requested that this not be added to the kernel since it would then 
> break all currently existing 64bit DM user tools. Newly compiled ones 
> would, of course, work, but you introduce a DM user tool versioning 
> problem, where the old 64 bit utils need to be used with old kernels, 
> and the new tools need to be used with the new kernels. As far as I 
> understood, this is the "official" line for the mainstream kernel. It 
> is my hope that the disties all decide to use Thornbers patch when they 
> do release, but only time will tell...

   Sorry, I probably wasn't making myself clear.

   I'm well aware of the issues surrounding this patch, and the fact
that it's never going to get into mainline kernels. However, it _does_
allow you to use DM with 32-bit user-space + 64-bit kernel, which was
my only point.

   Hugo.

-- 
=== Hugo Mills: hugo@... carfax.org.uk | darksatanic.net | lug.org.uk ===
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