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From: Keir Fraser <keir.fraser@eu.citrix.com>
To: Sarina Canelake <sarina.canelake@Oracle.Com>,
	"xen-devel@lists.xensource.com" <xen-devel@lists.xensource.com>
Subject: Re: [RFC] new totalmem= boot parameter
Date: Mon, 19 Jul 2010 19:11:19 +0100	[thread overview]
Message-ID: <C86A53D7.1B016%keir.fraser@eu.citrix.com> (raw)
In-Reply-To: <682e4bcf-71e3-4b49-a25b-79404ae470bb@default>

On 19/07/2010 18:56, "Sarina Canelake" <sarina.canelake@Oracle.Com> 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

  reply	other threads:[~2010-07-19 18:11 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2010-07-19 17:56 [RFC] new totalmem= boot parameter Sarina Canelake
2010-07-19 18:11 ` Keir Fraser [this message]
2010-07-20 21:26   ` Sarina Canelake
2010-07-20 21:55     ` Konrad Rzeszutek Wilk
2010-07-21  7:46     ` Keir Fraser

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