From: Joerg Roedel <joro@8bytes.org>
To: Zach Pfeffer <zpfeffer@codeaurora.org>
Cc: Hari Kanigeri <hari.kanigeri@gmail.com>,
Daniel Walker <dwalker@codeaurora.org>,
Andi Kleen <andi@firstfloor.org>,
Randy Dunlap <randy.dunlap@oracle.com>,
mel@csn.ul.ie, linux-mm@kvack.org, linux-kernel@vger.kernel.org,
linux-arm-msm@vger.kernel.org, linux-omap@vger.kernel.org,
linux-arm-kernel@lists.infradead.org
Subject: Re: [RFC 3/3] mm: iommu: The Virtual Contiguous Memory Manager
Date: Wed, 14 Jul 2010 21:34:03 +0200 [thread overview]
Message-ID: <20100714193403.GC23755@8bytes.org> (raw)
In-Reply-To: <4C3BF7C1.9040904@codeaurora.org>
On Mon, Jul 12, 2010 at 10:21:05PM -0700, Zach Pfeffer wrote:
> Joerg Roedel wrote:
> > The DMA-API already does this with the help of IOMMUs if they are
> > present. What is the benefit of your approach over that?
>
> The grist to the DMA-API mill is the opaque scatterlist. Each
> scatterlist element brings together a physical address and a bus
> address that may be different. The set of scatterlist elements
> constitute both the set of physical buffers and the mappings to those
> buffers. My approach separates these two things into a struct physmem
> which contains the set of physical buffers and a struct reservation
> which contains the set of bus addresses (or device addresses). Each
> element in the struct physmem may be of various lengths (without
> resorting to chaining). A map call maps the one set to the other.
Okay, thats a different concept, where is the benefit?
Joerg
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next prev parent reply other threads:[~2010-07-14 19:34 UTC|newest]
Thread overview: 48+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-06-30 5:55 [RFC 1/3] mm: iommu: An API to unify IOMMU, CPU and device memory management Zach Pfeffer
2010-06-30 5:55 ` [RFC 2/3] mm: iommu: A physical allocator for the VCMM Zach Pfeffer
2010-06-30 5:55 ` [RFC 3/3] mm: iommu: The Virtual Contiguous Memory Manager Zach Pfeffer
2010-07-01 17:17 ` Randy Dunlap
2010-07-01 18:02 ` Andi Kleen
2010-07-01 19:28 ` Daniel Walker
2010-07-01 19:38 ` Andi Kleen
2010-07-01 19:42 ` Daniel Walker
2010-07-01 22:15 ` Hari Kanigeri
2010-07-02 7:09 ` Zach Pfeffer
2010-07-10 14:36 ` Joerg Roedel
2010-07-13 5:21 ` Zach Pfeffer
2010-07-14 19:34 ` Joerg Roedel [this message]
2010-07-15 1:18 ` Zach Pfeffer
2010-07-01 22:00 ` Zach Pfeffer
2010-07-01 22:05 ` Daniel Walker
2010-07-02 7:33 ` Zach Pfeffer
2010-07-10 14:56 ` Joerg Roedel
2010-07-13 5:46 ` Zach Pfeffer
2010-07-13 5:59 ` FUJITA Tomonori
2010-07-13 8:20 ` Alan Cox
2010-07-13 8:30 ` FUJITA Tomonori
2010-07-13 8:42 ` Alan Cox
2010-07-13 8:45 ` FUJITA Tomonori
2010-07-13 9:02 ` Russell King - ARM Linux
2010-07-14 1:59 ` FUJITA Tomonori
2010-07-22 3:50 ` Zach Pfeffer
2010-07-22 4:47 ` FUJITA Tomonori
2010-07-22 16:33 ` Zach Pfeffer
2010-07-22 7:51 ` Russell King - ARM Linux
2010-07-22 16:13 ` Zach Pfeffer
2010-07-13 12:06 ` Zach Pfeffer
2010-07-01 22:51 ` Hari Kanigeri
2010-07-02 7:29 ` Zach Pfeffer
2010-07-01 23:00 ` Andi Kleen
2010-07-02 6:17 ` Zach Pfeffer
2010-07-02 8:22 ` Andi Kleen
2010-07-02 18:42 ` Zach Pfeffer
2010-07-10 15:11 ` Joerg Roedel
2010-07-13 5:52 ` Zach Pfeffer
2010-07-03 6:36 ` Zach Pfeffer
2010-07-10 14:54 ` Joerg Roedel
2010-07-13 5:27 ` Zach Pfeffer
2010-07-01 20:59 ` Paul Walmsley
2010-07-01 21:48 ` Randy Dunlap
2010-06-30 23:40 ` [RFC 1/3] mm: iommu: An API to unify IOMMU, CPU and device memory management Randy Dunlap
2010-07-01 7:16 ` Zach Pfeffer
2010-07-02 7:00 ` Paul Mundt
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