From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail143.messagelabs.com (mail143.messagelabs.com [216.82.254.35]) by kanga.kvack.org (Postfix) with SMTP id 567176B024D for ; Thu, 22 Jul 2010 12:28:23 -0400 (EDT) Date: Thu, 22 Jul 2010 09:28:20 -0700 From: Zach Pfeffer Subject: Re: [RFC 1/3 v3] mm: iommu: An API to unify IOMMU, CPU and device memory management Message-ID: <20100722162818.GD10255@codeaurora.org> References: <20100715014148.GC2239@codeaurora.org> <20100719082213.GA7421@n2100.arm.linux.org.uk> <20100720221959.GC12250@codeaurora.org> <20100721104356S.fujita.tomonori@lab.ntt.co.jp> <20100722043034.GC22559@codeaurora.org> <20100722073917.GC6802@n2100.arm.linux.org.uk> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20100722073917.GC6802@n2100.arm.linux.org.uk> Sender: owner-linux-mm@kvack.org To: Russell King - ARM Linux Cc: FUJITA Tomonori , ebiederm@xmission.com, linux-arch@vger.kernel.org, dwalker@codeaurora.org, mel@csn.ul.ie, linux-arm-msm@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, andi@firstfloor.org, linux-omap@vger.kernel.org, linux-arm-kernel@lists.infradead.org List-ID: On Thu, Jul 22, 2010 at 08:39:17AM +0100, Russell King - ARM Linux wrote: > On Wed, Jul 21, 2010 at 09:30:34PM -0700, Zach Pfeffer wrote: > > This goes to the nub of the issue. We need a lot of 1 MB physically > > contiguous chunks. The system is going to fragment and we'll never get > > our 12 1 MB chunks that we'll need, since the DMA API allocator uses > > the system pool it will never succeed. > > By the "DMA API allocator" I assume you mean the coherent DMA interface, > The DMA coherent API and DMA streaming APIs are two separate sub-interfaces > of the DMA API and are not dependent on each other. I didn't know that, but yes. As far as I can tell they both allocate memory from the VM. We'd need a way to hook in our our own minimized mapping allocator. -- 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/ . Don't email: email@kvack.org