From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:50100) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1X89ct-0004gO-C9 for qemu-devel@nongnu.org; Fri, 18 Jul 2014 10:59:19 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1X89cj-00078l-7y for qemu-devel@nongnu.org; Fri, 18 Jul 2014 10:59:11 -0400 Received: from mail1.windriver.com ([147.11.146.13]:47055) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1X89ce-00077x-8p for qemu-devel@nongnu.org; Fri, 18 Jul 2014 10:59:01 -0400 Received: from ALA-HCA.corp.ad.wrs.com (ala-hca.corp.ad.wrs.com [147.11.189.40]) by mail1.windriver.com (8.14.5/8.14.5) with ESMTP id s6IEwrCP023746 (version=TLSv1/SSLv3 cipher=AES128-SHA bits=128 verify=FAIL) for ; Fri, 18 Jul 2014 07:58:54 -0700 (PDT) Message-ID: <53C9362C.8040507@windriver.com> Date: Fri, 18 Jul 2014 08:58:52 -0600 From: Chris Friesen MIME-Version: 1.0 Content-Type: text/plain; charset="ISO-8859-1"; format=flowed Content-Transfer-Encoding: 7bit Subject: [Qemu-devel] is there a limit on the number of in-flight I/O operations? List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-devel@nongnu.org Hi, I've recently run up against an interesting issue where I had a number of guests running and when I started doing heavy disk I/O on a virtio disk (backed via ceph rbd) the memory consumption spiked and triggered the OOM-killer. I want to reserve some memory for I/O, but I don't know how much it can use in the worst-case. Is there a limit on the number of in-flight I/O operations? (Preferably as a configurable option, but even hard-coded would be good to know as well.) Thanks, Chris