From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752367AbeEGPTa (ORCPT ); Mon, 7 May 2018 11:19:30 -0400 Received: from bombadil.infradead.org ([198.137.202.133]:55810 "EHLO bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752276AbeEGPT1 (ORCPT ); Mon, 7 May 2018 11:19:27 -0400 Date: Mon, 7 May 2018 12:19:16 -0300 From: Mauro Carvalho Chehab To: Laurent Pinchart Cc: Fabien Dessenne , Jean-Christophe Trotin , Yasunari Takiguchi , Sakari Ailus , "Luis R. Rodriguez" , linux-mm@kvack.org, linux-kernel@vger.kernel.org, linux-media@vger.kernel.org Subject: Re: Are media drivers abusing of GFP_DMA? - was: Re: [LSF/MM TOPIC NOTES] x86 ZONE_DMA love Message-ID: <20180507121916.4eb7f5b2@vento.lan> In-Reply-To: <3561479.qPIcrWnXEC@avalon> References: <20180426215406.GB27853@wotan.suse.de> <20180505130815.53a26955@vento.lan> <3561479.qPIcrWnXEC@avalon> X-Mailer: Claws Mail 3.16.0 (GTK+ 2.24.32; x86_64-redhat-linux-gnu) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Em Mon, 07 May 2018 16:26:08 +0300 Laurent Pinchart escreveu: > Hi Mauro, > > On Saturday, 5 May 2018 19:08:15 EEST Mauro Carvalho Chehab wrote: > > There was a recent discussion about the use/abuse of GFP_DMA flag when > > allocating memories at LSF/MM 2018 (see Luis notes enclosed). > > > > The idea seems to be to remove it, using CMA instead. Before doing that, > > better to check if what we have on media is are valid use cases for it, or > > if it is there just due to some misunderstanding (or because it was > > copied from some other code). > > > > Hans de Goede sent us today a patch stopping abuse at gspca, and I'm > > also posting today two other patches meant to stop abuse of it on USB > > drivers. Still, there are 4 platform drivers using it: > > > > $ git grep -l -E "GFP_DMA\\b" drivers/media/ > > drivers/media/platform/omap3isp/ispstat.c > > drivers/media/platform/sti/bdisp/bdisp-hw.c > > drivers/media/platform/sti/hva/hva-mem.c > > drivers/media/spi/cxd2880-spi.c > > > > Could you please check if GFP_DMA is really needed there, or if it is > > just because of some cut-and-paste from some other place? > > I started looking at that for the omap3isp driver but Sakari beat me at > submitting a patch. GFP_DMA isn't needed for omap3isp. > Thank you both for looking into it. Regards, Mauro Thanks, Mauro