From mboxrd@z Thu Jan 1 00:00:00 1970 From: Pasi =?iso-8859-1?Q?K=E4rkk=E4inen?= Subject: Re: Memory allocation going seriously wonky on 4.1.1 Date: Sat, 1 Oct 2011 15:07:06 +0300 Message-ID: <20111001120706.GZ12984@reaktio.net> References: <4E85DB1A.5060606@overnetdata.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Content-Disposition: inline In-Reply-To: <4E85DB1A.5060606@overnetdata.com> List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Sender: xen-devel-bounces@lists.xensource.com Errors-To: xen-devel-bounces@lists.xensource.com To: Anthony Wright Cc: "xen-devel@lists.xensource.com" List-Id: xen-devel@lists.xenproject.org On Fri, Sep 30, 2011 at 04:07:06PM +0100, Anthony Wright wrote: > I have a machine with 16GB of RAM running 32 bit xen 4.1.1 with Dom0 > running a 3.0.4 linux kernel and 23 paravirtualized DomUs. > Hey, Why 32bit Xen? I think all (most?) hypervisor testing happens with 64bit Xen. Note that you can still have 32bit dom0 kernel with 64b hypervisor. > As the free ram gets to 2391 MB free the system behaves as if it's got > no more ram, and starts grabbing ram from Dom0, before getting even more > confused and failing to start DomUs and eventually crashing the whole > machine. I have attached a tarball with the output of xl dmesg, xl info > & xl list at various points. > - Do you use dom0_mem= parameter for Xen? - Did you disable dom0 ballooning? http://wiki.xen.org/xenwiki/XenBestPractices > Stage 1 > Everything is fine, Dom0 has 2000MB according to xl list, and 'xl info' > says there is 2405MB free. > - How much memory did dom0 initially have? - Did you use mem= parameter for dom0 kernel (vmlinuz) ? See: http://wiki.xen.org/xenwiki/Linux_30_bugs > Stage 2 > I have increased the memory for the DomU labelled 10-4 from 700MB to > 1000MB, Dom0 has 1713MB and 'xl info' says there is 2391MB free. > > Stage 3 > I have tried to increase the memory for the DomU labelled 13-4 from > 700MB to 1000MB, but it failed on the 'xl create' displaying the message > 'failed to free memory for the domain'. Dom0 has 1413MB and 'xl info' > says there is 3391MB free. > > State 4 > I tried to create the 13-4 DomU again, and this time it succeeds. Dom0 > has 1413MB and 'xl info' says there is 2391MB free. > > If I repeatedly stop and start DomUs at this point, particularly if I > request more ram, the machine locks up. This may be due to lack of Dom0 ram. -- Pasi