From mboxrd@z Thu Jan 1 00:00:00 1970 From: Avi Kivity Subject: Re: KVM on old kernels pre-2.6.28 Date: Thu, 27 Jan 2011 11:55:54 +0200 Message-ID: <4D41412A.2090001@redhat.com> References: <4D405116.2040206@shiftmail.org> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Cc: KVM mailing list To: Asdo Return-path: Received: from mx1.redhat.com ([209.132.183.28]:52087 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753889Ab1A0J4A (ORCPT ); Thu, 27 Jan 2011 04:56:00 -0500 In-Reply-To: <4D405116.2040206@shiftmail.org> Sender: kvm-owner@vger.kernel.org List-ID: 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