From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail190.messagelabs.com (mail190.messagelabs.com [216.82.249.51]) by kanga.kvack.org (Postfix) with SMTP id C18716B0087 for ; Thu, 23 Dec 2010 08:41:33 -0500 (EST) Received: by bwz16 with SMTP id 16so7947643bwz.14 for ; Thu, 23 Dec 2010 05:41:31 -0800 (PST) From: Michal Nazarewicz Subject: Re: [PATCHv8 00/12] Contiguous Memory Allocator References: <20101223100642.GD3636@n2100.arm.linux.org.uk> 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> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Sender: owner-linux-mm@kvack.org 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 List-ID: 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, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Fight unfair telecom policy in Canada: sign http://dissolvethecrtc.ca/ Don't email: email@kvack.org