From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753516AbYKKXDj (ORCPT ); Tue, 11 Nov 2008 18:03:39 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752315AbYKKXDU (ORCPT ); Tue, 11 Nov 2008 18:03:20 -0500 Received: from mx2.redhat.com ([66.187.237.31]:39570 "EHLO mx2.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752146AbYKKXDT (ORCPT ); Tue, 11 Nov 2008 18:03:19 -0500 Message-ID: <491A0F17.2070706@redhat.com> Date: Wed, 12 Nov 2008 01:02:47 +0200 From: Izik Eidus User-Agent: Thunderbird 2.0.0.17 (X11/20081009) MIME-Version: 1.0 To: Jonathan Corbet CC: linux-kernel@vger.kernel.org, linux-mm@kvack.org, kvm@vger.kernel.org, aarcange@redhat.com, chrisw@redhat.com, avi@redhat.com Subject: Re: [PATCH 3/4] add ksm kernel shared memory driver References: <1226409701-14831-1-git-send-email-ieidus@redhat.com> <1226409701-14831-2-git-send-email-ieidus@redhat.com> <1226409701-14831-3-git-send-email-ieidus@redhat.com> <1226409701-14831-4-git-send-email-ieidus@redhat.com> <20081111150345.7fff8ff2@bike.lwn.net> <491A0483.3010504@redhat.com> <20081111153028.422b301a@bike.lwn.net> In-Reply-To: <20081111153028.422b301a@bike.lwn.net> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Jonathan Corbet wrote: > > What about things like cache effects from scanning all those pages? My > guess is that, if you're trying to run dozens of Windows guests, cache > usage is not at the top of your list of concerns, but I could be > wrong. Usually am... > Ok, ksm does make the cache of the cpu dirty when scanning the pages (but the scanning happen slowly slowly and cache usually get dirty much faster) But infact it improve the cache by the fact that it make many ptes point to the same page so if before we had 12 process touching 12 diffrent physical page they would dirty the page but now they will touch just one... so i guess it depend on how you see it... > Thanks, > > jon >