From mboxrd@z Thu Jan  1 00:00:00 1970
From: Dave McCracken <dcm@mccr.org>
Subject: Re: [PATCH xen-unstable] Remove PSE flag from guest CR4
Date: Mon, 14 Sep 2009 14:47:44 -0500
Message-ID: <200909141447.44271.dcm@mccr.org>
References: <C6D43F08.14B08%keir.fraser@eu.citrix.com>
	<200909141253.38621.dcm@mccr.org> <4AAE947A.8010009@goop.org>
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To: Jeremy Fitzhardinge <jeremy@goop.org>
Cc: Xen Developers List <xen-devel@lists.xensource.com>, Keir Fraser <keir.fraser@eu.citrix.com>
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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