From mboxrd@z Thu Jan 1 00:00:00 1970 From: Andres Lagar-Cavilla Subject: Re: [PATCH 03/14]: libxenlight, 8MB slack for PV domains Date: Tue, 01 Dec 2009 09:15:19 -0500 Message-ID: <4B1524F7.30905@lagarcavilla.com> References: <4B1418C2.1060907@lagarcavilla.com> <20091201063440.GA15810@gwig.uk.xensource.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20091201063440.GA15810@gwig.uk.xensource.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: Vincent Hanquez Cc: "xen-devel@lists.xensource.com" , Stefano Stabellini List-Id: xen-devel@lists.xenproject.org The 8mb slack is not real memory allocated. It's extra room in the pfn space. The memory's domain allocation remains capped at the amount intended. I haven't seen anyone in xen-devel for five years needing more slack than that ') Particularly since the network rx flipping path stopped being the default Andres Vincent Hanquez wrote: > On Mon, Nov 30, 2009 at 07:10:58PM +0000, Andres Lagar-Cavilla wrote: > >> Contemplate 8MB of slack for PV domains, since they >> do ballooning (or flipping network rx) and need >> some extra room in their pfn space. >> >> Signed-off-by: Andres Lagar-Cavilla >> > > this probably should be in the build structure. not magically adding 8 mb without the > toolstack knowing, otherwise no toolstack can provide more or less slacks on a > per domain basis. And it make precise memory handling a nightmare, and thus > dynamic memory handling too. in some way this parameter is just like the > shadow_memory one in the hvm build structure. > >