From mboxrd@z Thu Jan 1 00:00:00 1970 From: Dor Laor Subject: Re: [PATCH] QEMU support for virtio balloon driver Date: Tue, 26 Feb 2008 01:45:38 +0200 Message-ID: <1203983138.3053.42.camel@localhost.localdomain> References: <1203968825-19161-1-git-send-email-aliguori@us.ibm.com> Reply-To: dor.laor@qumranet.com Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Cc: kvm-devel@lists.sourceforge.net, Marcelo Tosatti , Avi Kivity To: Anthony Liguori Return-path: In-Reply-To: <1203968825-19161-1-git-send-email-aliguori@us.ibm.com> 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 On Mon, 2008-02-25 at 13:47 -0600, Anthony Liguori wrote: > This patch adds support to QEMU for Rusty's recently introduce virtio balloon > driver. The user-facing portions of this are the introduction of a "balloon" > and "info balloon" command in the monitor. > The patch looks good. Might be a good idea to split it into 2 (balloon vs s->vdev.get_config patch. > Right now madvise() is commented out since it causes host panics. Ballooning > is still functional though--the host just doesn't reclaim the memory > immediately. > Since the mmu notifiers are not merged into 2.6.25 even, we need a temporary solution for it. There are two+ options: 1. Use the ksm (shared pages) scan and zero ballooned pages. This way the memory will be quickly picked up by the kernel. 2. Add in-kernel atomic ioctl for zapping the mmu + madvise 2+. Some sort of mmu notifiers backport (hard and hacky). IMHO 2 is the best option. btw: Izik's ksm module enable running 50 1G xp guests over a 16G host even without the ballooning running! ------------------------------------------------------------------------- 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/