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Date: Sat, 28 Feb 2009 10:39:58 -0800
From: Arjan van de Ven <arjan@infradead.org>
To: Ingo Molnar <mingo@elte.hu>
Cc: Linus Torvalds <torvalds@linux-foundation.org>,
       Nick Piggin <nickpiggin@yahoo.com.au>, Salman Qazi <sqazi@google.com>,
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       Thomas Gleixner <tglx@linutronix.de>, "H. Peter Anvin" <hpa@zytor.com>,
       Andi Kleen <andi@firstfloor.org>
Subject: Re: [patch] x86, mm: pass in 'total' to __copy_from_user_*nocache()
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On Sat, 28 Feb 2009 19:27:59 +0100
Ingo Molnar <mingo@elte.hu> wrote:

> 
> OTOH, given how draconian non-temporal stores are, i'm leaning 
> towards removing them from the x86 code altogether. If it matter 
> to performance somewhere it can be reintroduced, based on really 
> well backed up numbers.

I think that is mostly the right approach; O_DIRECT could be the
exception to that (because there we don't only wipe it from the cpu
cache due to DMA, it even gets wiped from the pagecache!).
But I can see that being too special of a case to care about in the
grand scheme of things (although the database people will now get upset
with me ;-)

-- 
Arjan van de Ven 	Intel Open Source Technology Centre
For development, discussion and tips for power savings, 
visit http://www.lesswatts.org