From mboxrd@z Thu Jan 1 00:00:00 1970 From: Avi Kivity Subject: Re: Re: [kvm] Re: Questions about duplicate memory work Date: Tue, 27 Sep 2011 12:49:29 +0300 Message-ID: <4E819C29.9040000@redhat.com> References: <20110925044511.GI30419@stodi.digitalkingdom.org> <20110926071803.GE18099@stodi.digitalkingdom.org> <20110927073842.GY18099@stodi.digitalkingdom.org> <20110927084843.GB28218@stodi.digitalkingdom.org> <20110927090000.GC28218@stodi.digitalkingdom.org> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Cc: Emmanuel Noobadmin , kvm@vger.kernel.org, Andrea Arcangeli To: Robin Lee Powell Return-path: Received: from mx1.redhat.com ([209.132.183.28]:23273 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751631Ab1I0Jtj (ORCPT ); Tue, 27 Sep 2011 05:49:39 -0400 In-Reply-To: <20110927090000.GC28218@stodi.digitalkingdom.org> Sender: kvm-owner@vger.kernel.org List-ID: On 09/27/2011 12:00 PM, Robin Lee Powell wrote: > On Tue, Sep 27, 2011 at 01:48:43AM -0700, Robin Lee Powell wrote: > > On Tue, Sep 27, 2011 at 04:41:33PM +0800, Emmanuel Noobadmin wrote: > > > On 9/27/11, Robin Lee Powell wrote: > > > > On Mon, Sep 26, 2011 at 04:15:37PM +0800, Emmanuel Noobadmin > > > > wrote: > > > >> It's unrelated to what you're actually using as the disks, > > > >> whether file or block devices like LVs. I think it just makes > > > >> KVM tell the host not to cache I/O done on the storage device. > > > > > > > > Wait, hold on, I think I had it backwards. > > > > > > > > It tells the *host* to not cache the device in question, or the > > > > *VMs* to not cache the device in question? > > > > > > I'm fairly certain it tells the qemu not to cache the device in > > > question. If you don't want the guest to cache their i/o, then the > > > guest OS should be configured if it allows that. Although I'm not > > > sure if it's possible to disable disk buffering/caching system > > > wide in Linux. > > > > OK, great, thanks. > > > > Now if I could just figure out how to stop the host from swapping > > out much of the VMs' qemu-kvm procs when it has almost a GiB of RAM > > left. -_- swappiness 0 doesn't seem to help there. > > Grrr. > > I turned swap off to clear it. A few minutes ago, this host was at > zero swap: > > top - 01:59:10 up 10 days, 15:17, 3 users, load average: 6.39, 4.26, 3.24 > Tasks: 151 total, 1 running, 150 sleeping, 0 stopped, 0 zombie > Cpu(s): 6.6%us, 1.0%sy, 0.0%ni, 85.9%id, 6.3%wa, 0.0%hi, 0.2%si, 0.0%st > Mem: 8128772k total, 6511116k used, 1617656k free, 14800k buffers > Swap: 8388604k total, 672828k used, 7715776k free, 97536k cached > > PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND > 2504 qemu 20 0 2425m 1.8g 448 S 10.0 23.4 3547:59 qemu-kvm > 2258 qemu 20 0 2425m 1.7g 444 S 2.7 21.7 1288:15 qemu-kvm > 18061 qemu 20 0 2433m 1.8g 428 S 2.3 23.4 401:01.99 qemu-kvm > 10335 qemu 20 0 1864m 861m 456 S 1.0 10.9 2:04.26 qemu-kvm > [snip] > > Why is it doing this?!? ;'( > Please post the contents of /proc/meminfo and /proc/zoneinfo when this is happening. -- error compiling committee.c: too many arguments to function