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[209.132.183.28]) by mx.google.com with ESMTPS id s1si822085qvc.125.2019.02.06.12.16.10 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Wed, 06 Feb 2019 12:16:10 -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-mx05.intmail.prod.int.phx2.redhat.com [10.5.11.15]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id D6A933DBFE; Wed, 6 Feb 2019 20:16:08 +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 6D26D6247B; Wed, 6 Feb 2019 20:16:05 +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 , Christopher Lameter Cc: 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 15:16:02 -0500 In-Reply-To: <20190206194055.GP21860@bombadil.infradead.org> References: <20190205175059.GB21617@iweiny-DESK2.sc.intel.com> <20190206095000.GA12006@quack2.suse.cz> <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> Organization: Red Hat, Inc. Content-Type: multipart/signed; micalg="pgp-sha256"; protocol="application/pgp-signature"; boundary="=-1dGH+hKU+Z7r3DIuLEHD" User-Agent: Evolution 3.30.4 (3.30.4-1.fc29) Mime-Version: 1.0 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.15 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.30]); Wed, 06 Feb 2019 20:16:09 +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: --=-1dGH+hKU+Z7r3DIuLEHD Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable On Wed, 2019-02-06 at 11:40 -0800, Matthew Wilcox wrote: > On Wed, Feb 06, 2019 at 07:16:21PM +0000, Christopher Lameter wrote: > >=20 > > though? If we only allow this use case then we may not have to worry ab= out > > long term GUP because DAX mapped files will stay in the physical locati= on > > regardless. >=20 > ... except for truncate. And now that I think about it, there was a > desire to support hot-unplug which also needed revoke. We already support hot unplug of RDMA devices. But it is extreme. How does hot unplug deal with a program running from the device (something that would have returned ETXTBSY)? --=20 Doug Ledford GPG KeyID: B826A3330E572FDD Key fingerprint =3D AE6B 1BDA 122B 23B4 265B 1274 B826 A333 0E57 2FDD --=-1dGH+hKU+Z7r3DIuLEHD Content-Type: application/pgp-signature; name="signature.asc" Content-Description: This is a digitally signed message part Content-Transfer-Encoding: 7bit -----BEGIN PGP SIGNATURE----- iQIzBAABCAAdFiEErmsb2hIrI7QmWxJ0uCajMw5XL90FAlxbQIIACgkQuCajMw5X L90bChAAgL7lcxfXKSmYLGA1OFdVg5chnIDS93XRvqgpb+yb4Tpb+DhVqhoT3bHY gUpE9yFtWmLsUVrtn0xquWw8VG5Ciqm3T+EA1l2yfD0deu7WchyEG6Ezg90IefFl BSl6rXHScee62dUztlmRPuj9Tu9x8zQlWzeYQ+HXWbXKbY1L47bYLaFgaHdYnDUX NdI+Dw84LQTpBxPjiQV+mBWPFaGSX1dxC6RKKxPHNMFLpEq9qt1Z2Z3NkceEc39v jCUmCkvDdYhLgk2Mb7rHIl8IrTrt3q2ASte9Qane1B/AQoKDvf+icpqggzrljbA4 gFnNLeIphEsj4RdxS8Jj4oAf80I57Od236KprxjfHNxWv6tpmuMpVuO8+2Wve9YF rskQFW76KIViYuvQpb8FHhmVQDZ+4fAsAoKlucf0lMbUaIyIbsR13qlyrsHViOfv fx7RPeVPNC+uct0qWeHkAJuivBZym/dqTHVuNVXkNOFAoiOXRpfIXA26XJlnT1aX CpRspY8yFawWEZonppyKyjbt3fMs3rZIFmxSh6vTEV8oXSlFYsIRG2Cu9bInZC1N B7ZuDVLvjCyizywq0VobCgEf3mlpG056WLSu9vXqO1BPT6ASI/GcI+JEG+NcitIX nz9Q1Dewt67LDUWm61KTkkiMEON8ljYxRgSkREIm6ksW3G35M48= =WK6h -----END PGP SIGNATURE----- --=-1dGH+hKU+Z7r3DIuLEHD--