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SubjectRe: vmalloced stacks on x86_64?
On Oct 25, 2014 2:15 AM, "Ingo Molnar" <mingo@kernel.org> wrote:
>
>
> * Andy Lutomirski <luto@amacapital.net> wrote:
>
> > Is there any good reason not to use vmalloc for x86_64 stacks?
>
> In addition to what hpa mentioned, __pa()/__va() on-kstack DMA
> gets tricky, for legacy drivers. (Not sure how many of these are
> left though.)

Hopefully very few. DMA debugging warns if the driver uses the DMA
API, and if the driver doesn't, then IOMMUs will break it.

virtio-net is an oddball offender. I have a patch.

--Andy

>
> Thanks,
>
> Ingo


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