From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:34775) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1Z8ML7-0008IO-BL for qemu-devel@nongnu.org; Fri, 26 Jun 2015 01:38:14 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1Z8ML6-0002pB-1N for qemu-devel@nongnu.org; Fri, 26 Jun 2015 01:38:13 -0400 Date: Fri, 26 Jun 2015 15:33:29 +1000 From: David Gibson Message-ID: <20150626053329.GD22737@voom.redhat.com> References: <1435212855-21685-1-git-send-email-bharata@linux.vnet.ibm.com> <1435212855-21685-7-git-send-email-bharata@linux.vnet.ibm.com> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="bjuZg6miEcdLYP6q" Content-Disposition: inline In-Reply-To: <1435212855-21685-7-git-send-email-bharata@linux.vnet.ibm.com> Subject: Re: [Qemu-devel] [RFC PATCH v5 6/6] spapr: Don't allow memory hotplug to memory less nodes List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Bharata B Rao Cc: mdroth@linux.vnet.ibm.com, aik@ozlabs.ru, agraf@suse.de, qemu-devel@nongnu.org, qemu-ppc@nongnu.org, tyreld@linux.vnet.ibm.com, nfont@linux.vnet.ibm.com, imammedo@redhat.com --bjuZg6miEcdLYP6q Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Thu, Jun 25, 2015 at 11:44:15AM +0530, Bharata B Rao wrote: > Currently PowerPC kernel doesn't allow hot-adding memory to memory-less > node, but instead will silently add the memory to the first node that has > some memory. This causes two unexpected behaviours for the user. >=20 > Memory gets hotplugged to a different node than what the user specified. > Since pc-dimm subsystem in QEMU still thinks that memory belongs to > memory-less node, a reboot will set things accordingly and the previously > hotplugged memory now ends in the right node. This appears as if some > memory moved from one node to another. >=20 > So until kernel starts supporting memory hotplug to memory-less > nodes, just prevent such attempts upfront in QEMU. >=20 > Signed-off-by: Bharata B Rao I presume you're talking about host kernel limitations here? If that does get changed in future we'll need some sort of ugly compat test in qemu to see if the new kernel can handle it, but there's no way to avoid that, so. Reviewed-by: David Gibson --=20 David Gibson | I'll have my music baroque, and my code david AT gibson.dropbear.id.au | minimalist, thank you. NOT _the_ _other_ | _way_ _around_! http://www.ozlabs.org/~dgibson --bjuZg6miEcdLYP6q Content-Type: application/pgp-signature -----BEGIN PGP SIGNATURE----- Version: GnuPG v1 iQIcBAEBAgAGBQJVjOQpAAoJEGw4ysog2bOSEuAQAJkLop/Y/meFxfQy68dUXfuY yeLqtWg998TSaAcvb0SQ51WQHD2DiftoxlWkwDrCn1XQElTjBU3uNovCne1jBcdZ c2z5i7UqaPJclRUwB3IQz4SFY6clhw6tm4vvVzguuUBRXIF1EIT8xkQ3/wpYL8j9 ej00q5k+Azc4/NzrDn82wm9ePjYza/Fx6rxnukL3i1it68JX5hrLaQTOziQwbxNA H8w6AsiFMGry9TM6YYqFc7yOEeupwN1SHCbldWBayrJitv4dWzSqLqQuZFJvRnvp MNqkIeJ0htBxxsEr5YnMyHHYSvwRAUEDCDNND7732Hb4UHlZWh19Qix9c3Y1yLxk /7UvyNXGkYFPaQEqvJnjAIit/YyYYqhoC3zMTlp/UJvYtJ0Cxn2PRA+cNQYYxoUb 80DTWnS9GhMN/IFcHB2OgF2XPI7YOHbm3fzGRJrwR2P576FhP8pZEU/a3i4O5DRs rNcIUybpD+uPbKazV9OVch2BhWcPf5j62L6ZdQz178XxwbRRRVSxuYPM7+I1ol1M cvl2YHg3cV+Mh7sp4RIvXEHdglLNdojrKEcL1LgobsJpenu60KE6bxU4NiUytwu6 U2v3WlvbxVlSMcBMj8PNjAoiVxcAtXcJVxxMye9MJP34YTNVgLS8/SjN8wPdWBW3 b7VDUg+vnkCKOZXbs/20 =zxLY -----END PGP SIGNATURE----- --bjuZg6miEcdLYP6q--