Re: [PATCH 8/8] eal: configure initial device probing

Kevin Traynor
2026-03-25T10:57:41Z

On 3/23/26 10:53 AM, David Marchand wrote:
> Some applications use port hotplug as their primary way for using DPDK
> resources.
> Having a systematic device probing is a problem when not all available
> resources will be used by the application, as such applications won't set
> an explicit allow list at startup.
>
> This is the case for OVS on systems with multiple mlx5 devices:
> one device can be used by the kernel while the other(s) are used by DPDK.
> In such a setup, the kernel used device may get reconfigured in
> unexpected ways and trigger issues like the one described by Kevin
> not so long ago in bugzilla 1873.
>
> Add an EAL option so that we can change the default behavior from
> block-listing to allow-listing which can be summed up as disabling
> automatic probing.
> In case some applications want to require automatic probing, add the
> opposite option.
>
> Signed-off-by: David Marchand <david.marchand@redhat.com>
> Acked-by: Bruce Richardson <bruce.richardson@intel.com>
> Reviewed-by: Robin Jarry <rjarry@redhat.com>
> ---
> Changes since RFC v2:
> - added -A short option alias as it seems intuitive to use with -a,

nit: I think I would have said '-B' as it's not allowing anything and
it's equivalent of adding a -b for all devices, but let's not bike shed
on it :-)

> - renamed option to --no-auto-probing (half Robin and half Thomas
> suggestions),
> - made -A and -b conflicting options,
> - added opposite option in case an application wants an explicit behavior,
> - updated unit tests accordingly,
> - updated documentation (namely some detail on --vdev),
>
> Changes since RFC v1:
> - changed approach following Bruce suggestion,
>
> ---
> app/test/test_eal_flags.c | 63 +++++++++++++++++++++++
> devtools/test-null.sh | 2 +-
> doc/guides/linux_gsg/eal_args.include.rst | 13 +++++
> lib/eal/common/eal_common_bus.c | 17 +++---
> lib/eal/common/eal_common_options.c | 10 ++++
> lib/eal/common/eal_internal_cfg.h | 1 +
> lib/eal/common/eal_option_list.h | 2 +
> 7 files changed, 101 insertions(+), 7 deletions(-)
>

LGTM

Acked-by: Kevin Traynor <ktraynor@redhat.com>