RE: Linux kernel version for DPDK 24.11

["Morten Brørup" <mb@smartsharesystems.com>]

> From: Stephen Hemminger [mailto:stephen@networkplumber.org]
> 
> On Tue, 13 Aug 2024 22:53:55 +0200
> Morten Brørup <mb@smartsharesystems.com> wrote:
> 
> > Stephen,
> >
> > Kernel 4.19 will reach EOL in December 2024 [1], so we should skip
> ahead to 5.4 (projected EOL December 2025) or 5.10 (projected EOL
> December 2026).
> >
> > For reference, the CIP project provides a SLTS (Super Long-Time
> Stable) kernel based on version 5.10 [2]. Their previous SLTS was based
> on kernel version 4.19.
> >
> > Based on the above information, it could make sense updating the DPDK
> minimum requirements for DPDK 24.11 to kernel version 5.10.
> >
> > You usually have a good overview of what is going on in the relevant
> distros. Could you please provide a doc patch like you have done before
> [3].
> >
> > [1]: https://www.kernel.org/category/releases.html
> > [2]: https://www.cip-project.org/blog/2022/04/04/cip-expands-work-on-
> slts-kernel-maintenance
> > [3]:
> https://git.dpdk.org/dpdk/commit/doc/guides/linux_gsg?id=0b9db7caa8c223a
> 541a323793068bc920789331c
> >
> >
> > Med venlig hilsen / Kind regards,
> > -Morten Brørup
> >
> 
> Yes, but we still have to support the distro's (Ubuntu, Fedora, RHEL)
> which may have older kernels.

Agree.

The DPDK doc [4] says:
"Required: Kernel version >= 4.19
The kernel version required is based on the oldest long term stable kernel available at kernel.org when the DPDK version is in development. Compatibility for recent distribution kernels will be kept, notably RHEL/CentOS 7."

[4]: https://doc.dpdk.org/guides/linux_gsg/sys_reqs.html

Also, your other mail about RHEL 8.8 was exactly the kind of distro insight was hoping for you to add to the discussion. :-)

> Kernel version doesn't matter as much now that drivers are gone.

ACK.

> But the issue is more about
> potentially missing stuff in header files.

Good point!
I recall Kernel uAPI headers being discussed on the tech board regarding VirtIO and Vhost.

@Maxime: Any preferences regarding kernel version for the Kernel uAPI headers? E.g. what are the oldest kernel versions of the Kernel uAPI headers required for respectively minimum or full support of the VirtIO and Vhost components in DPDK?

Do we want to be conservative and stick with 4.19 and RHEL/CentOS 7?
Or pick a supported kernel version newer than 4.19 and maybe upgrade the "notably" part to RHEL 8?