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Subject: Re: [Linaro-mm-sig] Re: [RFC PATCH 00/10] Device Memory TCP
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To:     Jason Gunthorpe <jgg@ziepe.ca>,
        Stephen Hemminger <stephen@networkplumber.org>
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        Sumit Semwal <sumit.semwal@linaro.org>,
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Am 20.07.23 um 01:24 schrieb Jason Gunthorpe:
> On Wed, Jul 19, 2023 at 10:57:11AM -0700, Stephen Hemminger wrote:
>
>> Naive idea.
>> Would it be possible for process to use mmap() on the GPU memory and then
>> do zero copy TCP receive some how? Or is this what is being proposed.
> It could be possible, but currently there is no API to recover the
> underlying dmabuf from the VMA backing the mmap.

Sorry for being a bit late, have been on vacation.

Well actually this was discussed before to work around problems with 
Windows applications through wine/proton.

Not 100% sure what the outcome of that was, but if I'm not completely 
mistaken getting the fd behind a VMA should be possible.

It might just not be the DMA-buf fd, because we use mmap() re-routing to 
be able to work around problems with the reverse tracking of mappings.

Christian.

>
> Also you can't just take arbitary struct pages from any old VMA and
> make them "netmem"
>
> Jason
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