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Message-ID: <1457049649.26149.11.camel@mhfsdcap03>
Subject: Re: [PATCH] arm64/dma-mapping: Add DMA_ATTR_ALLOC_SINGLE_PAGES
 support
From: Yong Wu <yong.wu@mediatek.com>
To: Doug Anderson <dianders@chromium.org>
CC: Joerg Roedel <joro@8bytes.org>, Catalin Marinas <catalin.marinas@arm.com>,
        Will Deacon <will.deacon@arm.com>,
        "Matthias Brugger" <matthias.bgg@gmail.com>,
        Robin Murphy <robin.murphy@arm.com>, Daniel Kurtz <djkurtz@google.com>,
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	<linux-arm-kernel@lists.infradead.org>,
        <iommu@lists.linux-foundation.org>,
        Marek Szyprowski <m.szyprowski@samsung.com>
Date: Fri, 4 Mar 2016 08:00:49 +0800
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On Thu, 2016-03-03 at 09:44 -0800, Doug Anderson wrote:
> Hi,
> 
> On Wed, Mar 2, 2016 at 10:54 AM, Yong Wu <yong.wu@mediatek.com> wrote:
> > Sometimes it is not worth for the iommu allocating big chunks.
> > Here we enable DMA_ATTR_ALLOC_SINGLE_PAGES which could help avoid to
> > allocate big chunks while iommu allocating buffer.
> >
> > More information about this attribute, please check Doug's commit[1].
> >
> > [1]: https://lkml.org/lkml/2016/1/11/720
> >
> > Cc: Robin Murphy <robin.murphy@arm.com>
> > Suggested-by: Douglas Anderson <dianders@chromium.org>
> > Signed-off-by: Yong Wu <yong.wu@mediatek.com>
> > ---
> >
> > Our video drivers may soon use this.
> >
> >  arch/arm64/mm/dma-mapping.c |  4 ++--
> >  drivers/iommu/dma-iommu.c   | 14 ++++++++++----
> >  include/linux/dma-iommu.h   |  4 ++--
> >  3 files changed, 14 insertions(+), 8 deletions(-)
> 
> It should also be mentioned that this depends on commit df05c6f6e0bb
> ("ARM: 8506/1: common: DMA-mapping: add DMA_ATTR_ALLOC_SINGLE_PAGES
> attribute") which is not in mainline quite yet.

Thanks. I will add it in the commit message.

> 
> Also please CC Marek Szyprowski on any future patches in this area
> since I saw a patch series from him that was touching this same area.

Will do.

> 
> Reviewed-by: Douglas Anderson <dianders@chromium.org>

Thanks.