From mboxrd@z Thu Jan 1 00:00:00 1970 From: Izik Eidus Subject: Re: [RFC][PATCH 0/5] Memory merging driver for Linux Date: Thu, 24 Jan 2008 11:26:25 +0200 Message-ID: <479859C1.1070301@qumranet.com> References: <4794C2E1.8040607@qumranet.com> <20080123231037.GA3629@sequoia.sous-sol.org> <479824EA.7070603@qumranet.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Cc: andrea-atKUWr5tajBWk0Htik3J/w@public.gmane.org, yaniv-atKUWr5tajBWk0Htik3J/w@public.gmane.org, kvm-devel , Chris Wright , linux-mm-Bw31MaZKKs3YtjvyW6yDsg@public.gmane.org To: Avi Kivity Return-path: In-Reply-To: <479824EA.7070603-atKUWr5tajBWk0Htik3J/w@public.gmane.org> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: kvm-devel-bounces-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@public.gmane.org Errors-To: kvm-devel-bounces-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@public.gmane.org List-Id: kvm.vger.kernel.org Avi Kivity wrote: > Chris Wright wrote: >> * Izik Eidus (izike-atKUWr5tajBWk0Htik3J/w@public.gmane.org) wrote: >> >>> this module find this identical data (pages) and merge them into one >>> single page >>> this new page is write protected so in any case the guest will try >>> to write to it do_wp_page will duplicate the page >>> >> >> What happens if you've merged more pages than you can recover on write >> faults? >> > > You start to swap. Just like Linux when you start to write on > fork()ed memory. > > A management application may start taking measures, like inflating > balloons and migrating to other hosts, but swapping is needed as a > last resort measure. > yes, write faults are getting into do_wp_page() that in turn create a new anonymous/swappable page so it is safe. -- woof. ------------------------------------------------------------------------- This SF.net email is sponsored by: Microsoft Defy all challenges. Microsoft(R) Visual Studio 2008. http://clk.atdmt.com/MRT/go/vse0120000070mrt/direct/01/