From mboxrd@z Thu Jan 1 00:00:00 1970 From: Doug Ledford Subject: Re: [LSF/MM TOPIC] Discuss least bad options for resolving longterm-GUP usage by RDMA Date: Wed, 06 Feb 2019 15:50:39 -0500 Message-ID: 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> Mime-Version: 1.0 Content-Type: multipart/signed; micalg="pgp-sha256"; protocol="application/pgp-signature"; boundary="=-npO7kZeSLN7JvETiEniW" Return-path: In-Reply-To: <20190206204954.GS21860@bombadil.infradead.org> Sender: linux-kernel-owner@vger.kernel.org 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 List-Id: linux-rdma@vger.kernel.org --=-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--