From mboxrd@z Thu Jan 1 00:00:00 1970 From: Thierry Reding Subject: Re: [PATCH v1 3/4] iommu/tegra: gart: Constify number of GART pages Date: Fri, 27 Apr 2018 11:49:53 +0200 Message-ID: <20180427094953.GN30388@ulmo> References: <954659be6760130f6ffd5e733db2ad58cbb8e6e4.1523304324.git.digetx@gmail.com> Mime-Version: 1.0 Content-Type: multipart/mixed; boundary="===============9127911692487236358==" Return-path: In-Reply-To: <954659be6760130f6ffd5e733db2ad58cbb8e6e4.1523304324.git.digetx-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: iommu-bounces-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org Errors-To: iommu-bounces-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org To: Dmitry Osipenko Cc: linux-tegra-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, iommu-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org, Jonathan Hunter List-Id: linux-tegra@vger.kernel.org --===============9127911692487236358== Content-Type: multipart/signed; micalg=pgp-sha256; protocol="application/pgp-signature"; boundary="qYrsQHciA3Wqs7Iv" Content-Disposition: inline --qYrsQHciA3Wqs7Iv Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Mon, Apr 09, 2018 at 11:07:21PM +0300, Dmitry Osipenko wrote: > GART has a fixed aperture size, hence the number of pages is constant. >=20 > Signed-off-by: Dmitry Osipenko > --- > drivers/iommu/tegra-gart.c | 14 ++++++++------ > 1 file changed, 8 insertions(+), 6 deletions(-) This doesn't really give a good explanation of why you want to do this. While it is certainly true that the aperture is fixed in size, I can imagine cases where somebody would want to restrict the aperture size (perhaps there's a fixed mapping somewhere near the end of the mapping that Linux shouldn't touch, or the GART aperture could be reduced to simulate out of IOVA memory situations). Without a good explanation why this is necessary I don't see why the current code should be changed. Thierry --qYrsQHciA3Wqs7Iv Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- iQIzBAABCAAdFiEEiOrDCAFJzPfAjcif3SOs138+s6EFAlri8kEACgkQ3SOs138+ s6FctRAAoUkhihlrmgwWCXP1zK7QT3+qpmdYyr1JNLF4i+0x73Qb0/wPoGu89JNV EcjSkaOIm7SQN+pvvPQnbKVuIJYM1PDKIdC+XNEtOTkDmfx2vhWL/X4sXnth+cia aabuCK0Q5epsaUIS7cvpKgChuOwmNeKADI3WSWZEpI2etqeCo6xIQ3FB+3rsoQCQ /eOzmk6eKsaySKFRLLWq8SmOjw8e3HFgU8OgHU1jk2vzACgn2kN8p4r7voV20MrF Y6xdlySnVLaKkXNNtpjCZ51eOQkD34T4T3YaIf6aNwvv5TT3tiEvPk4zoHNq0/aB o9vFOYc8F5IApoLAx4N1KKItk2F9HuvpK2DSqlQRH6VJqUw4PL1qu+8Rq6wWhofC p4IR0iEcCa9NpHZrF3jAJdNhrOo/3vA2aFyOJwg7UYCFZIGd4gCNa24TZxlhp2Z7 6XDnqijmQHuQcl2wtvpwdRnpBXNQ5E2dvKpbNvRUsoPeD/1G25CaDySt2ol1mx3i ebOtpYSJ+oH/qNz+Da6qjH/agVtBYYjvpT6kA9fAr5MnF6/d/vCmt5TbdYpb4tio Y5mrcD488qIAifg6a1r/O2xq6v+q3h9NnyN4MNbibfuwRXaT+csBb5wYL9jlFC2P okwV9TwsbaVbh1lOZlALGKKt2HGhJYED4qKxgLd4pfUlPiCMN8w= =x0GZ -----END PGP SIGNATURE----- --qYrsQHciA3Wqs7Iv-- --===============9127911692487236358== Content-Type: text/plain; charset="us-ascii" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit Content-Disposition: inline --===============9127911692487236358==-- From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932547AbeD0Jt6 (ORCPT ); Fri, 27 Apr 2018 05:49:58 -0400 Received: from mail-wm0-f65.google.com ([74.125.82.65]:40746 "EHLO mail-wm0-f65.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757800AbeD0Jt4 (ORCPT ); Fri, 27 Apr 2018 05:49:56 -0400 X-Google-Smtp-Source: AB8JxZrxtC9XsLJ6/WVm3m5h3jOHSLgWnHtAt2/nJ2xYWpFrDRBsmV15r//5hHEylNe5p9CwpJV1pw== Date: Fri, 27 Apr 2018 11:49:53 +0200 From: Thierry Reding To: Dmitry Osipenko Cc: Jonathan Hunter , Joerg Roedel , iommu@lists.linux-foundation.org, linux-tegra@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH v1 3/4] iommu/tegra: gart: Constify number of GART pages Message-ID: <20180427094953.GN30388@ulmo> References: <954659be6760130f6ffd5e733db2ad58cbb8e6e4.1523304324.git.digetx@gmail.com> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha256; protocol="application/pgp-signature"; boundary="qYrsQHciA3Wqs7Iv" Content-Disposition: inline In-Reply-To: <954659be6760130f6ffd5e733db2ad58cbb8e6e4.1523304324.git.digetx@gmail.com> User-Agent: Mutt/1.9.5 (2018-04-13) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org --qYrsQHciA3Wqs7Iv Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Mon, Apr 09, 2018 at 11:07:21PM +0300, Dmitry Osipenko wrote: > GART has a fixed aperture size, hence the number of pages is constant. >=20 > Signed-off-by: Dmitry Osipenko > --- > drivers/iommu/tegra-gart.c | 14 ++++++++------ > 1 file changed, 8 insertions(+), 6 deletions(-) This doesn't really give a good explanation of why you want to do this. While it is certainly true that the aperture is fixed in size, I can imagine cases where somebody would want to restrict the aperture size (perhaps there's a fixed mapping somewhere near the end of the mapping that Linux shouldn't touch, or the GART aperture could be reduced to simulate out of IOVA memory situations). Without a good explanation why this is necessary I don't see why the current code should be changed. Thierry --qYrsQHciA3Wqs7Iv Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- iQIzBAABCAAdFiEEiOrDCAFJzPfAjcif3SOs138+s6EFAlri8kEACgkQ3SOs138+ s6FctRAAoUkhihlrmgwWCXP1zK7QT3+qpmdYyr1JNLF4i+0x73Qb0/wPoGu89JNV EcjSkaOIm7SQN+pvvPQnbKVuIJYM1PDKIdC+XNEtOTkDmfx2vhWL/X4sXnth+cia aabuCK0Q5epsaUIS7cvpKgChuOwmNeKADI3WSWZEpI2etqeCo6xIQ3FB+3rsoQCQ /eOzmk6eKsaySKFRLLWq8SmOjw8e3HFgU8OgHU1jk2vzACgn2kN8p4r7voV20MrF Y6xdlySnVLaKkXNNtpjCZ51eOQkD34T4T3YaIf6aNwvv5TT3tiEvPk4zoHNq0/aB o9vFOYc8F5IApoLAx4N1KKItk2F9HuvpK2DSqlQRH6VJqUw4PL1qu+8Rq6wWhofC p4IR0iEcCa9NpHZrF3jAJdNhrOo/3vA2aFyOJwg7UYCFZIGd4gCNa24TZxlhp2Z7 6XDnqijmQHuQcl2wtvpwdRnpBXNQ5E2dvKpbNvRUsoPeD/1G25CaDySt2ol1mx3i ebOtpYSJ+oH/qNz+Da6qjH/agVtBYYjvpT6kA9fAr5MnF6/d/vCmt5TbdYpb4tio Y5mrcD488qIAifg6a1r/O2xq6v+q3h9NnyN4MNbibfuwRXaT+csBb5wYL9jlFC2P okwV9TwsbaVbh1lOZlALGKKt2HGhJYED4qKxgLd4pfUlPiCMN8w= =x0GZ -----END PGP SIGNATURE----- --qYrsQHciA3Wqs7Iv--