From mboxrd@z Thu Jan 1 00:00:00 1970 From: Keir Fraser Subject: Re: [RFC] new totalmem= boot parameter Date: Mon, 19 Jul 2010 19:11:19 +0100 Message-ID: References: <682e4bcf-71e3-4b49-a25b-79404ae470bb@default> Mime-Version: 1.0 Content-Type: text/plain; charset="US-ASCII" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <682e4bcf-71e3-4b49-a25b-79404ae470bb@default> List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Sender: xen-devel-bounces@lists.xensource.com Errors-To: xen-devel-bounces@lists.xensource.com To: Sarina Canelake , "xen-devel@lists.xensource.com" List-Id: xen-devel@lists.xenproject.org On 19/07/2010 18:56, "Sarina Canelake" wrote: > We have a need for ensuring the total RAM available to [Xen / the kernel] at > boot is X MB because there are situations in which you wish to limit the > amount of RAM available to a box. The existing mem= option doesn't work > because it limits the maximum physical address, NOT the amount of available > RAM. Many, if not all, systems contain a substantial memory hole below 4 Gb, > typically a 0.5 or 1 Gb hole from 3-4 Gb. Thus, on a system with 6 Gb of RAM, > requesting mem=4096M will yield a box with maximum physical address in the 4 > Gb neighborhood but perhaps only 3 or 3.5 actual gigs of RAM available. It doesn't sound *very* useful. But then neither is mem= really. We can add something like this if you really need it. So what's the motivation? -- Keir