Re: [dpdk-dev] [PATCH] memory: do not use base-virtaddr in secondary processes

[Alejandro Lucero <alejandro.lucero@netronome.com>]

On Mon, Jun 18, 2018 at 8:03 PM, Stojaczyk, DariuszX <
dariuszx.stojaczyk@intel.com> wrote:

>
> > -----Original Message-----
> > From: Alejandro Lucero [mailto:alejandro.lucero@netronome.com]
> > Sent: Monday, June 18, 2018 7:22 PM
> >
> > Should not be better to handle these allocations being aware about the
> > problem for secondary processes?
> >
> > I do not know exactly what are the (other) reasons behind base-virtaddr,
> > but it turns out NFP requires this to be used when DPDK apps executed
> > by non-root users.
> >
> > I'm working on a RFC for handling our specific case, that could also be
> > required for other devices, and this change would make the NFP unusable
> > for the secondary processes.
> >
>
> The only place base-virtaddr is used in secondary processes in DPDK 18.05
> is this shadow memseg mapping, which shouldn't really need to be accessed
> by anyone else than DPDK EAL.


Yes, I'm aware this is EAL code.

Can you point me out to an NFP guide or some code that describes this in
> more detail?
>

As I said, I'm working on a RFC. I will send something shortly. But I could
give you an advance: the hugepages needs to be mapped below certain virtual
address, 1TB, and I'm afraid that includes the primary and also the
secondary processes. At least if any process can send or receive packets
to/from a NFP.


>
> If we're talking about base-virtaddr for hugepages, then that's always
> inherited from the primary process, regardless of what base-virtaddr is
> supplied to the secondary.
>
>
But, is not your patch avoiding to use that base-virtaddr for secondary
processes?


> Regards!
> D.
>