From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Denis V. Lunev" Subject: Re: [PATCH 0/2] virtio_balloon: do not change memory amount visible via /proc/meminfo Date: Mon, 31 Aug 2015 10:33:21 +0300 Message-ID: <55E40341.60500@openvz.org> References: <1440020989-10824-1-git-send-email-den@openvz.org> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii"; Format="flowed" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <1440020989-10824-1-git-send-email-den@openvz.org> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: virtualization-bounces@lists.linux-foundation.org Errors-To: virtualization-bounces@lists.linux-foundation.org To: "Michael S. Tsirkin" Cc: virtualization@lists.linux-foundation.org List-Id: virtualization@lists.linuxfoundation.org On 08/20/2015 12:49 AM, Denis V. Lunev wrote: > Though there is a problem in this setup. The end-user and hosting provider > have signed SLA agreement in which some amount of memory is guaranted for > the guest. The good thing is that this memory will be given to the guest > when the guest will really need it (f.e. with OOM in guest and with > VIRTIO_BALLOON_F_DEFLATE_ON_OOM configuration flag set). The bad thing > is that end-user does not know this. > > Balloon by default reduce the amount of memory exposed to the end-user > each time when the page is stolen from guest or returned back by using > adjust_managed_page_count and thus /proc/meminfo shows reduced amount > of memory. > > Fortunately the solution is simple, we should just avoid to call > adjust_managed_page_count with VIRTIO_BALLOON_F_DEFLATE_ON_OOM set. > > Please note that neither VMWare ballon nor HyperV balloon do not care > about proper handling of adjust_managed_page_count at all. > > Signed-off-by: Denis V. Lunev > CC: Michael S. Tsirkin ping Michael, the issue is important for us. Can you pls look? Den