Date: Thu, 7 Dec 2006 02:24:30 +0100 (CET)
From: Roman Zippel <zippel@linux-m68k.org>
To: Linus Torvalds <torvalds@osdl.org>
cc: Matthew Wilcox <matthew@wil.cx>, Christoph Lameter <clameter@sgi.com>,
       David Howells <dhowells@redhat.com>, Andrew Morton <akpm@osdl.org>,
       linux-kernel@vger.kernel.org, linux-arch@vger.kernel.org
Subject: Re: [PATCH] WorkStruct: Implement generic UP cmpxchg() where an arch
 doesn't support it
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References: <20061206164314.19870.33519.stgit@warthog.cambridge.redhat.com>
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Hi,

On Wed, 6 Dec 2006, Linus Torvalds wrote:

> > > Any _real_ CPU will simply never care about _anything_ else than just the 
> > > size of the datum in question.
> > 
> > ..or alignment which a dedicated atomic type would allow to be attached.
> 
> Can you give any example of a real CPU where alignment matters?
> 
> Sure, it needs to be naturally aligned, but that's true of _any_ type in 
> the kernel. We don't do unaligneds without "get_unaligned()" and friends.

m68060 produces a trap for unaligned atomic access, unfortunately standard 
alignment is smaller than this.

bye, Roman
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