Path: csiph.com!news.mixmin.net!aioe.org!gothmog.csi.it!bofh.it!news.nic.it!robomod From: Thierry Reding Newsgroups: linux.kernel Subject: Re: [PATCH 2/4] arm64: defconfig: Set cma heap size to 128MB Date: Mon, 22 Aug 2016 11:10:01 +0200 Message-ID: References: X-PGP-Universal: processed; by hqnvupgp08.nvidia.com on Mon, 22 Aug 2016 02:02:03 -0700 MIME-Version: 1.0 X-Nvconfidentiality: public User-Agent: Mutt/1.6.2 (2016-07-01) X-Originating-IP: [10.2.70.221] X-Clientproxiedby: UKMAIL102.nvidia.com (10.26.138.15) To UKMAIL101.nvidia.com (10.26.138.13) Content-Type: multipart/signed; micalg=pgp-sha256; protocol="application/pgp-signature"; boundary="SkvwRMAIpAhPCcCJ" Content-Disposition: inline Sender: robomod@news.nic.it List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Approved: robomod@news.nic.it Lines: 50 Organization: linux.* mail to news gateway X-Original-Cc: , , , , , , , , , , , , , Xinliang Liu X-Original-Date: Mon, 22 Aug 2016 11:06:01 +0200 X-Original-Message-ID: <20160822090600.GB25947@ulmo.ba.sec> X-Original-References: <1471621328-21102-1-git-send-email-guodong.xu@linaro.org> <1471621328-21102-3-git-send-email-guodong.xu@linaro.org> X-Original-Sender: linux-kernel-owner@vger.kernel.org Xref: csiph.com linux.kernel:1467488 --SkvwRMAIpAhPCcCJ Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Fri, Aug 19, 2016 at 11:42:06PM +0800, Guodong Xu wrote: > From: Xinliang Liu >=20 > For debian linux, cma heap is used to allocate graphic buffers. > The default size is 16 MB which is not enought. > So increase the size to 128 MB. >=20 > Signed-off-by: Xinliang Liu > --- > arch/arm64/configs/defconfig | 1 + > 1 file changed, 1 insertion(+) This is a bad idea. You're increasing this heap for all users of the default configuration (which on 64-bit ARM is everyone, really). Many of the devices don't require the CMA except maybe for the occasional very small buffer. Most implement some form of IOMMU support that removes the need for large amounts of contiguous physical memory. I think it's a better idea to have some bootloader append a cma=3D128 to the kernel command-line if necessary. Thierry --SkvwRMAIpAhPCcCJ Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- Version: GnuPG v2 iQIcBAABCAAGBQJXusB1AAoJEN0jrNd/PrOhI9sP/2ViuUs5e0ShzFCu+RBHQ+S5 DbRg5yQ/t/jk3XFUHolBYdPK2FDZuHezuyKfHu7amxl+iPu5205lamsV3RqDOjas +nKDvVASTxOFoYbvjdgyvru9R94S8g3aO+QcrsFLuu5LaE8fQ8byoI8hGOza7ZpZ 8xtDGtvD/q9TwGXwGAe9JDjNa6N5ncWC2SqgKkrV7tpHf5Pa/m/GT8zBZ5ek6mKM c5NAGsJsv3DfJWONy0EuIyHx0UyS8TMwnc/DPsFOPx2pOok5UY1HIU9VEjpJTfcN mt6bNwb1qUxjw4pgtq5ifjlO74h/EqD5KauLh7YcvgQ0B+ImfLTdv2BC1Iow3/YM SNPW8ImnkgqASfBFTWgpGozG3zDRH1Bdawv6SOzQZDT7tuk/qZOMIwTSjCCmd6J3 dAE6Q/4ixsCZv8erf76gi38WWHWvi6ddzUb5aGen5dmBxLbmIoW4Fry8w7JjAGnw 853mQhzjdWuMDOiseV3dMYXtKdgxtBKevhLhlC7B5fy8SG0dstysqEBOQeBV8510 EYM6vr6c908VcMpTDrKmnhmU8+aCK/piEPOfXfGEDHAqIGyp8yMP/JD/IIt53z+V NyDEE+3JqDekh4bj+5OI1Z0aBi4TGW2qv3/BAb7rq4vvN6N+Hv55o/ePjlYVH/hP zQLL+Ws5ugiNQeMUVc2L =VoTr -----END PGP SIGNATURE----- --SkvwRMAIpAhPCcCJ--