From mboxrd@z Thu Jan 1 00:00:00 1970 From: Avi Kivity Subject: Re: [kvm-devel] performance with guests running 2.4 kernels (specifically RHEL3) Date: Wed, 28 May 2008 17:57:21 +0300 Message-ID: <483D72D1.7080803@qumranet.com> References: <482C1633.5070302@qumranet.com> <482E5F9C.6000207@cisco.com> <482FCEE1.5040306@qumranet.com> <4830F90A.1020809@cisco.com> <4830FE8D.6010006@cisco.com> <48318E64.8090706@qumranet.com> <4832DDEB.4000100@qumranet.com> <4835EEF5.9010600@cisco.com> <483D391F.7050007@qumranet.com> <483D6898.2050605@cisco.com> <20080528144850.GX27375@duo.random> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Cc: "David S. Ahern" , kvm@vger.kernel.org To: Andrea Arcangeli Return-path: Received: from bzq-179-150-194.static.bezeqint.net ([212.179.150.194]:49032 "EHLO il.qumranet.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751054AbYE1O50 (ORCPT ); Wed, 28 May 2008 10:57:26 -0400 In-Reply-To: <20080528144850.GX27375@duo.random> Sender: kvm-owner@vger.kernel.org List-ID: Andrea Arcangeli wrote: > On Wed, May 28, 2008 at 08:13:44AM -0600, David S. Ahern wrote: > >> Weird. Could it be something about the hosts? >> > > Note that the VM itself will never make use of kmap. The VM is "data" > agonistic. The VM has never any idea with the data contained by the > pages. kmap/kmap_atomic/kunmap_atomic are only need to access _data_. > > What about CONFIG_HIGHPTE? -- Do not meddle in the internals of kernels, for they are subtle and quick to panic.