From mboxrd@z Thu Jan 1 00:00:00 1970 From: Avi Kivity Subject: Re: KVM architecture docs Date: Wed, 05 Mar 2008 07:19:02 +0200 Message-ID: <47CE2D46.1030608@qumranet.com> References: <47CC1E91.7050207@sintesi80.it> <47CC421F.5070003@qumranet.com> <47CD0769.6020104@qumranet.com> <47CD14B6.9010908@qumranet.com> <90eb1dc70803040617j3590c52bj3d77a327143bda5f@mail.gmail.com> <47CD6601.5050907@qumranet.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Cc: kvm-devel@lists.sourceforge.net, Javier Guerra To: Zhao Forrest Return-path: In-Reply-To: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: kvm-devel-bounces@lists.sourceforge.net Errors-To: kvm-devel-bounces@lists.sourceforge.net List-Id: kvm.vger.kernel.org Zhao Forrest wrote: >> - swapping allows you to overcommit memory >> > > Normally swapping mechanism choose the Least Recently Used(LRU) pages > of a process to be swapped out. When KVM uses MMU notifier in linux > kernel to implement swapping for VM, could KVM choose LRU pages of a > VM to swap out? If so, could you give a brief description about how > this is implemented? > The Linux memory manager approximates LRU by scanning pages for the accessed bit, which is set in the pte by the processor when a page is accessed through that pte. mmu notifiers provide a callback for the check, so that kvm can check the accessed bit on the shadow ptes. -- Do not meddle in the internals of kernels, for they are subtle and quick to panic. ------------------------------------------------------------------------- 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/