Re: [PATCH] swiotlb: avoid double copy with swiotlb on tx socket

[Luigi Rizzo]

On Mon, Aug 24, 2026 at 10:59 AM Dragos Tatulea <dtatulea@xxxxxxxxxx> wrote:
>
...
> An example of this is Jiri's system_cc_shared heap which is a dma-buf
> heap with decrypted memory for userspace.
>
> > I am still looking into this, I was planning to bring this up in the
> > upcoming LPC.
> > I will give this patch a try. However, I believe that we need a more
> > generalised concept for CoCo pre-decrypted allocators in the kernel.
> >
> There is a talk at LPC in the networking track about this [2]. This is
> exactly the type of discussion that I was hoping to have there.
>
> Besides the issues mentioned in this thread we've also found that a lot
> of overhead can come only from swiotlb allocations when running many queues.
>
> I will add information about this series in my talk. Hopefully I will also
> have time to add some numbers for comparison.
>
> Sorry for the late reply but I spotted this thread only now by
> accident.
>
> [1] https://lore.kernel.org/all/20260325192352.437608-3-jiri@xxxxxxxxxxx/
> [2] https://lpc.events/event/20/contributions/2464

Thank you for the feedback and links.

Do you have some code describing [2] ?

I just sent a cleaned-up v2 of my previous series, if you want to try
it please use the latter.

cheers
luigi