From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:41611) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1Xr8AX-0002SM-Es for qemu-devel@nongnu.org; Wed, 19 Nov 2014 11:31:54 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1Xr8AS-0003b2-He for qemu-devel@nongnu.org; Wed, 19 Nov 2014 11:31:49 -0500 Received: from mx1.redhat.com ([209.132.183.28]:56038) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1Xr8AS-0003aw-9Z for qemu-devel@nongnu.org; Wed, 19 Nov 2014 11:31:44 -0500 Message-ID: <546CC5E7.3010908@redhat.com> Date: Wed, 19 Nov 2014 09:31:35 -0700 From: Eric Blake MIME-Version: 1.0 References: <1416201070-11448-1-git-send-email-zhang.zhanghailiang@huawei.com> <1416201070-11448-2-git-send-email-zhang.zhanghailiang@huawei.com> <20141119103246.GE26395@redhat.com> <20141119101336.5893db6c@redhat.com> <546CBCB3.9040606@redhat.com> <20141119160628.GF28563@redhat.com> In-Reply-To: <20141119160628.GF28563@redhat.com> Content-Type: multipart/signed; micalg=pgp-sha256; protocol="application/pgp-signature"; boundary="H8gteot1JeGjRk3vV5GRIiUo7m5C7Pfxx" Subject: Re: [Qemu-devel] [PATCH v2 1/3] pc-dimm: add a function to calculate VM's current RAM size List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: "Michael S. Tsirkin" Cc: qemu-devel@nongnu.org, imammedo@redhat.com, peter.huangpeng@huawei.com, zhanghailiang , Luiz Capitulino This is an OpenPGP/MIME signed message (RFC 4880 and 3156) --H8gteot1JeGjRk3vV5GRIiUo7m5C7Pfxx Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable On 11/19/2014 09:06 AM, Michael S. Tsirkin wrote: >>>> This affects QMP right? >>> >>> I think later patches will tell how. CC'ing Eric. >> >> As far as I can tell, this is just correcting a reporting issue; the >> existing QMP commands/events for tracking balloon size will now proper= ly >> account for hotplugged memory. >> >> What I don't know is if this change in semantics will affect any users= =2E >> Libvirt is not yet supporting memory hotplug, so ideally, fixing this= >> bug before libvirt uses memory hotplug means libvirt will never have t= o >> worry about qemu versions that do incorrect reporting. >> >> The alternative is to declare that the existing QMP commands cannot >> change in semantics for the existing members that it reports, and must= >> instead report additional dictionary members describing the amount of >> hot-plugged memory, and then require that the client add the numbers >> together itself. That sounds mean to the client, so I'm hoping we don= 't >> have to go there. >=20 >=20 > IOW you ack this patch for 2.2? >=20 Is memory hotplug one of the new features in 2.2? If so, then yes, we should get its semantics right from the start (this is a bug fix to avoid a release with broken semantics). On the other hand, if hotplug existed in 2.1, then we already have a release with odd semantics, so delaying this fix until 2.3 and leaving 2.2 with the same odd semantics would not hurt, and it then becomes a judgment call of whether we are rushing in a possibly incomplete solution by trying to get this into 2.2. (Sorry I haven't been following the history of memory hotplug closer= ) --=20 Eric Blake eblake redhat com +1-919-301-3266 Libvirt virtualization library http://libvirt.org --H8gteot1JeGjRk3vV5GRIiUo7m5C7Pfxx Content-Type: application/pgp-signature; name="signature.asc" Content-Description: OpenPGP digital signature Content-Disposition: attachment; filename="signature.asc" -----BEGIN PGP SIGNATURE----- Version: GnuPG v1 Comment: Public key at http://people.redhat.com/eblake/eblake.gpg iQEcBAEBCAAGBQJUbMXnAAoJEKeha0olJ0NqC0oH/RkkvMfXs3EMz/Z4Vs5LBq56 qLLe5OViE6kKMza0RcKbm12qJY0X1nL3JwNW5pNhcZ0FiSxVrDYSIjf6h8lybuq0 AbApONyuVOpMNLcOnBC4L0Q6dMx8PkhOvNGnTMAOFmOxg89YgGKmLSorX0V0eIV0 XvvQNeVo2VcNriAUr/9PftXoLrGntVrlAdWbdiI2yTZ+9cSn4Q12XpN0y/cug08Y +rlyiuTWB+axQbdWidMi1lruX/4vyMC/uqnsxk8tCrYKCQvGhGLjTFDd0WaBmE8j KKGm18woi0twn22rFsl1dKhE/qrBS7rem7G9qMEDB034SbkCyKVJGzT1CSiGfbM= =0yHI -----END PGP SIGNATURE----- --H8gteot1JeGjRk3vV5GRIiUo7m5C7Pfxx--