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From: Avi Kivity <avi@redhat.com>
To: Asdo <asdo@shiftmail.org>
Cc: KVM mailing list <kvm@vger.kernel.org>
Subject: Re: KVM on old kernels pre-2.6.28
Date: Thu, 27 Jan 2011 11:55:54 +0200	[thread overview]
Message-ID: <4D41412A.2090001@redhat.com> (raw)
In-Reply-To: <4D405116.2040206@shiftmail.org>

On 01/26/2011 06:51 PM, Asdo wrote:
> Some time ago in this list it was mentioned that old kernels pre-2.6.28
> don't work well with KVM.
> (in particular we have a machine with 2.6.24)
>

pre 2.6.27 kernels don't have mmu notifiers and thus don't handle 
overcommit well.  No idea if there's anything wrong with 2.6.27 itself.

> Unfortunately the type of problem was not mentioned in the posts I could
> find. Is that a performance problem, a stability problem, or a data
> corruption problem... ?
>
> And I would also like to know if the "problem" can be worked around by
> installing a new kvm-kmod like 2.6.36.2  or we really need to upgrade
> the whole kernel to get rid of it.

The mmu notifier issue requires 2.6.27 or above.  Using kvm-kmod allows 
you to run a newer kvm on an older kernel, but doesn't fix 
infrastructure issues like I mentioned.

> (I was thinking at installing a new qemu-kvm like the 0.12.5 on that)

0.12.5 is already old.  But why are you running such old and unsupported 
kernels?  I recommend either running a distribution kernel, where 
someone takes care of bug fixes and security updates, or running one of 
the stable tree kernels.

-- 
error compiling committee.c: too many arguments to function


  reply	other threads:[~2011-01-27  9:56 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2011-01-26 16:51 KVM on old kernels pre-2.6.28 Asdo
2011-01-27  9:55 ` Avi Kivity [this message]
2011-01-27 18:09   ` David Ahern
2011-01-30 13:03     ` Avi Kivity
2011-01-30 16:37       ` David Ahern
2011-01-30 17:03         ` Avi Kivity
2011-02-03 14:33   ` Asdo
2011-02-03 14:38     ` Avi Kivity

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