From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from psmtp.com (na3sys010amx137.postini.com [74.125.245.137]) by kanga.kvack.org (Postfix) with SMTP id 3371B6B0082 for ; Mon, 28 May 2012 04:19:45 -0400 (EDT) Received: from euspt1 (mailout4.w1.samsung.com [210.118.77.14]) by mailout4.w1.samsung.com (Oracle Communications Messaging Server 7u4-24.01(7.0.4.24.0) 64bit (built Nov 17 2011)) with ESMTP id <0M4Q001E04I1CE40@mailout4.w1.samsung.com> for linux-mm@kvack.org; Mon, 28 May 2012 09:20:25 +0100 (BST) Received: from linux.samsung.com ([106.116.38.10]) by spt1.w1.samsung.com (iPlanet Messaging Server 5.2 Patch 2 (built Jul 14 2004)) with ESMTPA id <0M4Q0027D4GU8J@spt1.w1.samsung.com> for linux-mm@kvack.org; Mon, 28 May 2012 09:19:43 +0100 (BST) Date: Mon, 28 May 2012 10:19:39 +0200 From: Marek Szyprowski Subject: RE: [PATCHv2 3/4] mm: vmalloc: add VM_DMA flag to indicate areas used by dma-mapping framework In-reply-to: Message-id: <001d01cd3caa$a05d0510$e1170f30$%szyprowski@samsung.com> MIME-version: 1.0 Content-type: text/plain; charset=us-ascii Content-language: pl Content-transfer-encoding: 7BIT References: <1337252085-22039-1-git-send-email-m.szyprowski@samsung.com> <1337252085-22039-4-git-send-email-m.szyprowski@samsung.com> <4FBB3B41.8010102@kernel.org> <01e501cd39a8$67f34ea0$37d9ebe0$%szyprowski@samsung.com> <20120524122854.GD11860@linux-sh.org> Sender: owner-linux-mm@kvack.org List-ID: To: 'KOSAKI Motohiro' , 'Paul Mundt' Cc: 'Minchan Kim' , linux-arm-kernel@lists.infradead.org, linaro-mm-sig@lists.linaro.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, 'Kyungmin Park' , 'Arnd Bergmann' , 'Russell King - ARM Linux' , 'Chunsang Jeong' , 'Krishna Reddy' , 'Konrad Rzeszutek Wilk' , 'Hiroshi Doyu' , 'Subash Patel' , 'Nick Piggin' Hello, On Sunday, May 27, 2012 2:35 PM KOSAKI Motohiro wrote: > On Thu, May 24, 2012 at 8:28 AM, Paul Mundt wrote: > > On Thu, May 24, 2012 at 02:26:12PM +0200, Marek Szyprowski wrote: > >> On Tuesday, May 22, 2012 9:08 AM Minchan Kim wrote: > >> > Hmm, VM_DMA would become generic flag? > >> > AFAIU, maybe VM_DMA would be used only on ARM arch. > >> > >> Right now yes, it will be used only on ARM architecture, but maybe other architecture will > >> start using it once it is available. > >> > > There's very little about the code in question that is ARM-specific to > > begin with. I plan to adopt similar changes on SH once the work has > > settled one way or the other, so we'll probably use the VMA flag there, > > too. > > I don't think VM_DMA is good idea because x86_64 has two dma zones. x86 unaware > patches make no sense. I see no problems to add VM_DMA64 later if x86_64 starts using vmalloc areas for creating kernel mappings for the dma buffers (I assume that there are 2 dma zones: one 32bit and one 64bit). Right now x86 and x86_64 don't use vmalloc areas for dma buffers, so I hardly see how this patch can be considered as 'x86 unaware'. Best regards -- Marek Szyprowski Samsung Poland R&D Center -- 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 internet charges in Canada: sign http://stopthemeter.ca/ Don't email: email@kvack.org