From mboxrd@z Thu Jan 1 00:00:00 1970 From: George Shuklin Subject: Re: a ton of kernel issues Date: Wed, 14 Dec 2011 01:10:39 +0400 Message-ID: <4EE7BF4F.7030700@gmail.com> References: <4EE675A8.3030609@niemail.de> <4EE71663.5040308@gmail.com> <4EE72A94.6040904@gmail.com> <20111213141835.GA32247@andromeda.dapyr.net> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii"; Format="flowed" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20111213141835.GA32247@andromeda.dapyr.net> List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Sender: xen-devel-bounces@lists.xensource.com Errors-To: xen-devel-bounces@lists.xensource.com To: Konrad Rzeszutek Wilk Cc: xen-devel@lists.xensource.com, sandr8@gmail.com List-Id: xen-devel@lists.xenproject.org On 13.12.2011 18:18, Konrad Rzeszutek Wilk wrote: >>> what glitches should one expect with 3.0+, and having the choice, >>> would it be better to go with 3.1 or even 3.2? >>> >> Right now I know about two of them: >> When you set up memory for virtual machine using xenballon, value in >> dom0 differ from value in domU. The issue is that -xen kernels 'hide' >> some memory in 'used' memory, and pv-ops just reducing TotalMem to value >> without that memory. Practically that means if you set up memory for >> domain to 2GiB client will saw only 1.95GiB and so on. >> >> The second issue is lack of support of 'pre-inflated balloon', means you >> can not set up memory-static-max to 2GiB, target to 1GiB and do 'memory >> grow' from 1 G to 2 G latter without VM reboot. -xen kernels allow this >> (up to memory-static-max limit). > Is all of this with 'xm' or with 'xl' tools? What happens when you 'grow' > the memory from 1G to 2G? Are you using the hotplug memory balloon or > the older one? This is xcp (with shutdowned squeezed, it not a problem), so we using direct calls to xc (domain_set_maxkb), but I can repeat this with xl (which one and only one available in XCP), with same results. If I create VM with static-max 2GiB, dynamic-max 1GiB, boot it, then: 1) with PV_ops I can go lower than 1GiB, but never any higher than 1GiB 2) with -xen kernels I can go upper to 2GiB. If I compile kernel with xenballoon hotplug option enabled, after some (very small) memory growth (within preallocated memory?) after future attempts I getting this message: [1935380.223401] System RAM resource 18000000 - 27ffffff cannot be added [1935380.223414] xen_balloon: reserve_additional_memory: add_memory() failed: -17 (tested with vanilla 3.0, 3.1 and some RCs of 3.2)