[PATCH v3] RFC deprecate RTE_MARKER in struct rte_mbuf

[Morten Brørup]

> From: Tyler Retzlaff [mailto:roretzla at linux.microsoft.com]
> Sent: Wednesday, 14 February 2024 00.33
> 
> Here is the latest iteration of the proposed change to allow struct
> rte_mbuf
> to be consumed by MSVC.
> 
> * Introduce an internal __rte_marker macro conditionally expanded for
> MSVC
>   vs existing users of the struct. At some point we can uncomment
> __rte_deprecated
>   to assist migration away from the current marker fields for
> applications
>   after appropriate announcement periods etc..
> 
> * Introduce anonymous unions to allow aliasing of the previous named
>   offsets by a *new* name.  The intention would be to convert the dpdk
> tree
>   to use the new names along with this change and enable
> __rte_deprecated
>   for dpdk builds (not applications) to avoid accidental re-
> introduction.
> 
> * The anonymous unions are now also used to pad cacheline0 and
> cacheline1 instead
>   of __rte_cache_min_aligned.

ACK. This design also seems reusable for similar structures.