From mboxrd@z Thu Jan 1 00:00:00 1970 From: David Vrabel Subject: Re: [PATCH] x86: set dom0's default maximum reservation to the initial number of pages Date: Wed, 21 Mar 2012 10:33:57 +0000 Message-ID: <4F69AE95.9010707@citrix.com> References: <1332267691-13179-1-git-send-email-david.vrabel@citrix.com> <4F69A1060200007800079D0E@nat28.tlf.novell.com> <4F69A654.4020900@citrix.com> <4F69B8010200007800079D86@nat28.tlf.novell.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <4F69B8010200007800079D86@nat28.tlf.novell.com> List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Sender: xen-devel-bounces@lists.xen.org Errors-To: xen-devel-bounces@lists.xen.org To: Jan Beulich Cc: Konrad Rzeszutek Wilk , "Keir (Xen.org)" , xen-devel List-Id: xen-devel@lists.xenproject.org On 21/03/12 10:14, Jan Beulich wrote: > On 21.03.12 at 10:58, David Vrabel wrote: >> The docs still need updating and I think the min:MMM option should be >> deprecated. > > Why should we deprecate min:? It can be useful when combined with > other sub-options, can't it? Not convinced of its utility but it does do something, so yes, it should be kept. >>>> This change means that with Linux 3.0.5 and later kernels, >>>> dom0_mem=512M has the same result as older, 'classic Xen' kernels. The >>>> older kernels used the initial number of pages to set the maximum >>>> number of pages and did not query the hypervisor for the maximum >>>> reservation. >>> >>> If the pv-ops kernels behave differently in this aspect than the forward >>> ported ones, then it should really be the newer one to get adjusted to >>> the original behavior (if so intended), unless the old behavior was >>> completely insane. Adjusting the hypervisor for a shortcoming(?) in a >>> particular implementation of a Dom0 kernel doesn't seem to be the right >>> route - please also consider non-Linux Dom0 kernels that might expect >>> the current behavior. >> >> The old behaviour did not allow dom0 to balloon up beyond the initial >> allocation so we don't what to go back to that. > > In pv-ops Linux Dom0 you mean? While I can't speak of non-Linux, > ballooning up beyond the initial allocation works fine in the legacy > and forward ported kernels. Perhaps I'm looking at a XenServer specific limitation. David