From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Jiang, Yunhong" Subject: RE: Re: [PATCH] Support swap a page from user spacetools -- Was RE: [RFC][PATCH] Basic support for page offline Date: Fri, 20 Mar 2009 18:13:13 +0800 Message-ID: References: Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: quoted-printable Return-path: In-Reply-To: Content-Language: en-US List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Sender: xen-devel-bounces@lists.xensource.com Errors-To: xen-devel-bounces@lists.xensource.com To: Keir Fraser , Jan Beulich Cc: Tim Deegan , "xen-devel@lists.xensource.com" List-Id: xen-devel@lists.xenproject.org Keir Fraser wrote: > On 20/03/2009 10:03, "Keir Fraser" wrote: >=20 >>>> Ah, you do a suspend-cancel/fast-resume? >>>=20 >>> Yes, that's suggested by Tim and I think that's meet our purpose quite >>> well.=20 >>=20 >> Okay, then I suggest you extend XENMEM_exchange so that in.mem_flags can >> tell that hypercall to copy data from old to new pages. XENMEMF_copy_dat= a? >=20 > Even this may not work. Old grants will reference the old > page. Subsequent > attempts by a backend to map the grant will fail. And the > resulting failed > I/Os will probably make the frontend driver throw a fit. Getting this > working with suspend-cancel seems pretty tricky. If there is grant map for it, I think we will fail since the reference is n= ot 1 when XENMEM_exchange. Or do you mean there is a reference in grant table but is not mapped still?= Will the refrence count be added when a page is granted? I'm not quite sur= e about this, but I think that will be same to original XENMEM_exchange. If= yes, we may have to update the grant information? The normal save-restore method may cause service broken, I think that's the= reason of choosing the suspend-cacel method. Thanks Yunhong Jiang >=20 > -- Keir=