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[209.132.183.28]) by mx.google.com with ESMTPS id h1si2871010qkj.187.2019.02.06.12.50.45 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Wed, 06 Feb 2019 12:50:46 -0800 (PST) Received-SPF: pass (google.com: domain of dledford@redhat.com designates 209.132.183.28 as permitted sender) client-ip=209.132.183.28; Authentication-Results: mx.google.com; spf=pass (google.com: domain of dledford@redhat.com designates 209.132.183.28 as permitted sender) smtp.mailfrom=dledford@redhat.com; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=redhat.com Received: from smtp.corp.redhat.com (int-mx08.intmail.prod.int.phx2.redhat.com [10.5.11.23]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 152B6144040; Wed, 6 Feb 2019 20:50:45 +0000 (UTC) Received: from haswell-e.nc.xsintricity.com (ovpn-112-17.rdu2.redhat.com [10.10.112.17]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 7A5AC1C94A; Wed, 6 Feb 2019 20:50:42 +0000 (UTC) Message-ID: Subject: Re: [LSF/MM TOPIC] Discuss least bad options for resolving longterm-GUP usage by RDMA From: Doug Ledford To: Matthew Wilcox Cc: Christopher Lameter , Jason Gunthorpe , Jan Kara , Ira Weiny , lsf-pc@lists.linux-foundation.org, linux-rdma@vger.kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, John Hubbard , Jerome Glisse , Dan Williams , Dave Chinner , Michal Hocko Date: Wed, 06 Feb 2019 15:50:39 -0500 In-Reply-To: <20190206204954.GS21860@bombadil.infradead.org> References: <20190206173114.GB12227@ziepe.ca> <20190206175233.GN21860@bombadil.infradead.org> <47820c4d696aee41225854071ec73373a273fd4a.camel@redhat.com> <01000168c43d594c-7979fcf8-b9c1-4bda-b29a-500efe001d66-000000@email.amazonses.com> <20190206194055.GP21860@bombadil.infradead.org> <20190206202021.GQ21860@bombadil.infradead.org> <20190206204128.GR21860@bombadil.infradead.org> <20190206204954.GS21860@bombadil.infradead.org> Organization: Red Hat, Inc. Content-Type: multipart/signed; micalg="pgp-sha256"; protocol="application/pgp-signature"; boundary="=-npO7kZeSLN7JvETiEniW" User-Agent: Evolution 3.30.4 (3.30.4-1.fc29) Mime-Version: 1.0 X-Scanned-By: MIMEDefang 2.84 on 10.5.11.23 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.38]); Wed, 06 Feb 2019 20:50:45 +0000 (UTC) X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: --=-npO7kZeSLN7JvETiEniW Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable On Wed, 2019-02-06 at 12:49 -0800, Matthew Wilcox wrote: > On Wed, Feb 06, 2019 at 03:47:53PM -0500, Doug Ledford wrote: > > On Wed, 2019-02-06 at 12:41 -0800, Matthew Wilcox wrote: > > > On Wed, Feb 06, 2019 at 03:28:35PM -0500, Doug Ledford wrote: > > > > On Wed, 2019-02-06 at 12:20 -0800, Matthew Wilcox wrote: > > > > > Not hot-unplugging the RDMA device but hot-unplugging an NV-DIMM. >=20 > ^^^ I think you missed this line ^^^ Indeed, I did ;-) >=20 > > You said "now that I think about it, there was a desire to support hot- > > unplug which also needed revoke". For us, hot unplug is done at the > > device level and means all connections must be torn down. So in the > > context of this argument, if people want revoke so DAX can migrate from > > one NV-DIMM to another, ok. But revoke does not help RDMA migrate. > >=20 > > If, instead, you mean that you want to support hot unplug of an NV-DIMM > > that is currently the target of RDMA transfers, then I believe > > Christoph's answer on this is correct. It all boils down to which > > device you are talking about doing the hot unplug on. --=20 Doug Ledford GPG KeyID: B826A3330E572FDD Key fingerprint =3D AE6B 1BDA 122B 23B4 265B 1274 B826 A333 0E57 2FDD --=-npO7kZeSLN7JvETiEniW Content-Type: application/pgp-signature; name="signature.asc" Content-Description: This is a digitally signed message part Content-Transfer-Encoding: 7bit -----BEGIN PGP SIGNATURE----- iQIzBAABCAAdFiEErmsb2hIrI7QmWxJ0uCajMw5XL90FAlxbSJ8ACgkQuCajMw5X L91Y+hAAusyH3LPRH/wvWQK4kvGUWublDXN9K/Udjlf1z1agPHTyDxMEP4lqYbkz +dlHYgggahnY4m/J8N1ctQ/wVqdxnT/aO/iKuAmZszWwPDNl6D6cksEXnW4Gsdh/ AGp+06hK1ZtigzRLXajHbcLZqgWTfCE8Y00PhiUe26M8BTx2dNM3pHvH0aQtkcnK I6k4ZBMu4t0zojN3flit89NuRnfE+1b0dnH+9XqzLlCKRmfN9ZnJtvBLu3vKyd1d wK2nms1N8Zsn7hrI0d7L8hDFZudfd7tcsdGLEKr48I6JcOnfppzr7fNl8hCT62xn xkE/HXyz1K8TQrKn8plAzGFFVANCy7VqQPD+xN49G7dg7+go9srl7OO0o5JxPdY2 xQlRSa03pP4/Qt2NS7+Ar0FUi9UAISSmcAc+A5hZAdEIICj9sjSavSotCx2jTFcB zHml+SejW2r5CEfPrDNzoeBe1m4H4nS113bSujtgjrVkW2uN3GrXLFwAaD0dKJSN YNXmbNxGUCcXPfWnL/AK27DXnmLhC48wRpk1YhHjuNpJ/kgwPVtO37QDqPK7wjpY 1tJigUxaFXfvfryOtTnvoPcZM5Icyo60ocREqJP4Y62xTbL2rLQvL7Qm1oZlO5jN ZIxjvEVS25lqOehKH6ldv0KP0Zqrv1CwQ7Q6FDDeSaeEcRrVyzg= =EurJ -----END PGP SIGNATURE----- --=-npO7kZeSLN7JvETiEniW--