Re: [PATCH 2/2] eal: add meson options for hotplug MP message buffer sizes

[Stephen Hemminger <stephen@networkplumber.org>]

On Tue, 24 Mar 2026 18:45:06 -0700
Long Li <longli@microsoft.com> wrote:

> Add meson build options to allow increasing the multi-process hotplug
> message buffer limits at build time for deployments with many NICs:
> - 'dev_mp_devargs_max_len' (default 128): max device args length
> - 'mp_max_param_len' (default 256): max MP IPC message param length
> 
> Example: meson setup build -Ddev_mp_devargs_max_len=256 -Dmp_max_param_len=512
> 
> Guard the existing #defines with #ifndef so the meson-generated values
> from rte_build_config.h take precedence when overridden.
> 
> Add a static_assert to ensure eal_dev_mp_req fits within the MP message
> param buffer, catching misconfiguration at compile time.
> 
> Note: all primary and secondary processes must be built with the same
> values, as these sizes affect shared IPC message struct layouts.
> 
> Signed-off-by: Long Li <longli@microsoft.com>



The whole mp API needs some work on sizing.
Ideally the message would be variable size and not include all the
file descriptors if not needed.

Even better it should be TLV encoded instead of fixed structure.
But doing this probably has to wait until 26.11.