From mboxrd@z Thu Jan 1 00:00:00 1970 From: Andres Lagar-Cavilla Subject: Re: [PATCH 3/7] libxenlight resend: 8mb physmap slack for pv domains Date: Thu, 03 Dec 2009 11:03:58 -0500 Message-ID: <4B17E16E.3000302@lagarcavilla.com> References: <4B16AB3F.4000809@lagarcavilla.com> <20091203161013.GB16684@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: <20091203161013.GB16684@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 No extra memory is being allocated at all in any way. The only impact is a wee bit larger p2m table. Andres Vincent Hanquez wrote: > On Wed, Dec 02, 2009 at 06:00:31PM +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. >> >> Note that this does not allocate any extra memory >> to the domain, it simply extends the physmap with >> some extra room for "bounce bufffering back" pfn's >> that are yielded to dom0. >> > > but the memory is still going off from somewhere isn't it ? > all those random memory constants spread around in xend took us quite some time > to get things right in XCP and XenServer, and also for keeping the library as > dumb as possible, I'ld rather have the toolstack set the field in the structure > (even if it end up beeing 8M all the time) than starting adding those things. > >