Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752880Ab0LWNle (ORCPT ); Thu, 23 Dec 2010 08:41:34 -0500 Received: from mail-bw0-f46.google.com ([209.85.214.46]:50703 "EHLO mail-bw0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752238Ab0LWNld (ORCPT ); Thu, 23 Dec 2010 08:41:33 -0500 DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=sender:from:to:cc:subject:references:x-face:face:x-url:x-pgp-fp :x-pgp:date:in-reply-to:message-id:user-agent:mime-version :content-type; b=SLMHzP7+YHPpb73Eoc2FBh7hyFtO4dwAGoDJhwR5YL45WJd3buUxEUmGD0kXB8mi/H CctUOeyHjNMqf6AFu37jVqFQbSM5gi6VUgVmB9c9zM2oN/akvgKFJQ/qzXF776ygV3vo 7i158cnvGRhFawHfX5POZmMuC+wHpGHAmcgno= From: Michal Nazarewicz To: Russell King - ARM Linux Cc: Kyungmin Park , linux-arm-kernel@lists.infradead.org, Daniel Walker , Johan MOSSBERG , Mel Gorman , linux-kernel@vger.kernel.org, linux-mm@kvack.org, Ankita Garg , Andrew Morton , linux-media@vger.kernel.org, KAMEZAWA Hiroyuki , Marek Szyprowski Subject: Re: [PATCHv8 00/12] Contiguous Memory Allocator References: <20101223100642.GD3636@n2100.arm.linux.org.uk> X-Face: PbkBB1w#)bOqd`iCe"Ds{e+!C7`pkC9a|f)Qo^BMQvy\q5x3?vDQJeN(DS?|-^$uMti[3D*#^_Ts"pU$jBQLq~Ud6iNwAw_r_o_4]|JO?]}P_}Nc&"p#D(ZgUb4uCNPe7~a[DbPG0T~!&c.y$Ur,=N4RT>]dNpd;KFrfMCylc}gc??'U2j,!8%xdD Face: 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 X-Url: http://mina86.com/ X-PGP-FP: 9134 06FA 7AD8 D134 9D0C C33F 532C CB00 B7C6 DF1E X-PGP: B7C6DF1E Date: Thu, 23 Dec 2010 14:41:26 +0100 In-Reply-To: <20101223100642.GD3636@n2100.arm.linux.org.uk> (Russell King's message of "Thu, 23 Dec 2010 10:06:42 +0000") Message-ID: <87k4j0ehdl.fsf@erwin.mina86.com> User-Agent: Gnus/5.110011 (No Gnus v0.11) Emacs/24.0 (Slckware Linux) MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1210 Lines: 27 Russell King - ARM Linux writes: > Has anyone addressed my issue with it that this is wide-open for > abuse by allocating large chunks of memory, and then remapping > them in some way with different attributes, thereby violating the > ARM architecture specification? > > In other words, do we _actually_ have a use for this which doesn't > involve doing something like allocating 32MB of memory from it, > remapping it so that it's DMA coherent, and then performing DMA > on the resulting buffer? Huge pages. Also, don't treat it as coherent memory and just flush/clear/invalidate cache before and after each DMA transaction. I never understood what's wrong with that approach. -- Best regards, _ _ .o. | Liege of Serenly Enlightened Majesty of o' \,=./ `o ..o | Computer Science, Michal "mina86" Nazarewicz (o o) ooo +------ooO--(_)--Ooo-- -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/