From mboxrd@z Thu Jan 1 00:00:00 1970 From: Keir Fraser Subject: Re: RFC: [0/2] Remove netloop by lazy copying in netback Date: Tue, 27 Mar 2007 09:31:15 +0100 Message-ID: References: <20070327081352.GA24634@gondor.apana.org.au> Mime-Version: 1.0 Content-Type: text/plain; charset="US-ASCII" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20070327081352.GA24634@gondor.apana.org.au> List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Sender: xen-devel-bounces@lists.xensource.com Errors-To: xen-devel-bounces@lists.xensource.com To: Herbert Xu Cc: Isaku Yamahata , Xen Development Mailing List List-Id: xen-devel@lists.xenproject.org On 27/3/07 09:13, "Herbert Xu" wrote: > I was actually thinking of Jose's scheme where it's mapped in on > demand. So you would still do your grant table map operation, > but instead of mapping it in as we do now it would simply notify > the hypervisor of the intention to map this page, and the hypervisor > can then map it in when it actually faults. That's not quite how Jose's patch works. The lazy mapping is done by the guest in his patch. If we're not going to go as far as supporting guest-visible 'p2m faults' then I think overall your original patch is probably the best approach so far. If I view the new hypercall as a special case of the existing unmap (which is an unmap-to-zero-pte special case) then it's not so bad. At least there should be very little new code in the hypervisor needed to implement it. We have a little while longer to think about this since the patches aren't for 3.0.5. -- Keir