Re: IOMMU keeping mapping over long period of time

[Jerome Glisse]

On Tue, Oct 18, 2011 at 11:56 AM, Andi Kleen <andi@xxxxxxxxxxxxxx> wrote:
> Jerome Glisse <j.glisse@xxxxxxxxx> writes:
>>
>> GPU for which we are interested have dma mask of 40bits at least, thus
>> they can work with high mem page. My main concern is when an iommu is
>> active, such amount of continuously mapped page might exhaust the iommu
>> address space. My understanding is that Intel & AMD iommu are capable of
>> growing their address space but is it somethings we can rely on ?
>
> I don't think relying on this is very wise. Better add some way to unmap
> when space is running short.
>
> -Andi
>

Maybe i should have add that the usecase involve the driver never knowing when
the GPU will make use of the mapped memory and this can happen anytime.

Cheers,
Jerome
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/