From: Will Deacon <will.deacon-5wv7dgnIgG8@public.gmane.org>
To: Robin Murphy <robin.murphy-5wv7dgnIgG8@public.gmane.org>
Cc: iommu-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org,
linux-arm-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org
Subject: Re: [PATCH v2 2/2] iommu/dma: Implement PCI allocation optimisation
Date: Mon, 23 Jan 2017 17:39:58 +0000 [thread overview]
Message-ID: <20170123173957.GD28914@arm.com> (raw)
In-Reply-To: <db8af3d98f2a717c51d007c9c36d3b8eb1acd9a1.1484572209.git.robin.murphy-5wv7dgnIgG8@public.gmane.org>
On Mon, Jan 16, 2017 at 01:24:55PM +0000, Robin Murphy wrote:
> Whilst PCI devices may have 64-bit DMA masks, they still benefit from
> using 32-bit addresses wherever possible in order to avoid DAC (PCI) or
> longer address packets (PCIe), which may incur a performance overhead.
> Implement the same optimisation as other allocators by trying to get a
> 32-bit address first, only falling back to the full mask if that fails.
>
> Signed-off-by: Robin Murphy <robin.murphy-5wv7dgnIgG8@public.gmane.org>
> ---
> drivers/iommu/dma-iommu.c | 21 +++++++++++++++------
> 1 file changed, 15 insertions(+), 6 deletions(-)
Looks good to me, and has the added benefit of getting PCI ethernet
working on Juno when using the SMMU. Unintended side-effect, but:
Acked-by: Will Deacon <will.deacon-5wv7dgnIgG8@public.gmane.org>
Will
WARNING: multiple messages have this Message-ID (diff)
From: will.deacon@arm.com (Will Deacon)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH v2 2/2] iommu/dma: Implement PCI allocation optimisation
Date: Mon, 23 Jan 2017 17:39:58 +0000 [thread overview]
Message-ID: <20170123173957.GD28914@arm.com> (raw)
In-Reply-To: <db8af3d98f2a717c51d007c9c36d3b8eb1acd9a1.1484572209.git.robin.murphy@arm.com>
On Mon, Jan 16, 2017 at 01:24:55PM +0000, Robin Murphy wrote:
> Whilst PCI devices may have 64-bit DMA masks, they still benefit from
> using 32-bit addresses wherever possible in order to avoid DAC (PCI) or
> longer address packets (PCIe), which may incur a performance overhead.
> Implement the same optimisation as other allocators by trying to get a
> 32-bit address first, only falling back to the full mask if that fails.
>
> Signed-off-by: Robin Murphy <robin.murphy@arm.com>
> ---
> drivers/iommu/dma-iommu.c | 21 +++++++++++++++------
> 1 file changed, 15 insertions(+), 6 deletions(-)
Looks good to me, and has the added benefit of getting PCI ethernet
working on Juno when using the SMMU. Unintended side-effect, but:
Acked-by: Will Deacon <will.deacon@arm.com>
Will
next prev parent reply other threads:[~2017-01-23 17:39 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-01-16 13:24 [PATCH v2 1/2] iommu/dma: Stop getting dma_32bit_pfn wrong Robin Murphy
2017-01-16 13:24 ` Robin Murphy
[not found] ` <d899aa686e7c8cb45142fa6785aa539ef3b88dec.1484572209.git.robin.murphy-5wv7dgnIgG8@public.gmane.org>
2017-01-16 13:24 ` [PATCH v2 2/2] iommu/dma: Implement PCI allocation optimisation Robin Murphy
2017-01-16 13:24 ` Robin Murphy
[not found] ` <db8af3d98f2a717c51d007c9c36d3b8eb1acd9a1.1484572209.git.robin.murphy-5wv7dgnIgG8@public.gmane.org>
2017-01-23 17:39 ` Will Deacon [this message]
2017-01-23 17:39 ` Will Deacon
2017-01-23 17:40 ` [PATCH v2 1/2] iommu/dma: Stop getting dma_32bit_pfn wrong Will Deacon
2017-01-23 17:40 ` Will Deacon
2017-01-30 15:16 ` Joerg Roedel
2017-01-30 15:16 ` Joerg Roedel
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