Re: [PATCH v7 24/27] x86: Add swiotlb force off support

From: Yinghai Lu
Date: Sat Dec 22 2012 - 00:12:01 EST


On Fri, Dec 21, 2012 at 6:42 PM, Eric W. Biederman
<ebiederm@xxxxxxxxxxxx> wrote:
> Konrad Rzeszutek Wilk <konrad.wilk@xxxxxxxxxx> writes:
>
>> On Mon, Dec 17, 2012 at 11:15:56PM -0800, Yinghai Lu wrote:
>>> So use could disable swiotlb from command line, even swiotlb support
>>> is compiled in. Just like we have intel_iommu=on and intel_iommu=off.
>>
>> You really need to spell out why this is useful.
>
> YH why can't we safely autodetect that the swiotlb is unusable when
> there is no memory below 4G free?

good point.

will give it try.

Yinghai
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