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[Xen-devel] Re: [PATCH xen-unstable] Remove PSE flag from guest CR4

To: Jeremy Fitzhardinge <jeremy@xxxxxxxx>
Subject: [Xen-devel] Re: [PATCH xen-unstable] Remove PSE flag from guest CR4
From: Dave McCracken <dcm@xxxxxxxx>
Date: Mon, 14 Sep 2009 14:47:44 -0500
Cc: Xen Developers List <xen-devel@xxxxxxxxxxxxxxxxxxx>, Keir Fraser <keir.fraser@xxxxxxxxxxxxx>
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On Monday 14 September 2009, Jeremy Fitzhardinge wrote:
> On 09/14/09 10:53, Dave McCracken wrote:
> > Linux assumes it will just work.
> >
> > Since hugepages in Linux are an optional feature the kernel will boot
> > even on a machine that doesn't support PSE.  Applications that use
> > hugepages will get a nasty error.
> 
> That sounds like a Linux bug; at the very least, it sounds very fragile
> to rely on this behaviour.

Perhaps, but hugepages has always worked like that.  I think the reality is 
that any machine small enough/old enough to not support PSE is way too small 
for hugepages to be useful on it, so no one tries to run it on those machines.

Dave McCracken

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