Re: [PATCH v4 0/2] node: add mbuf dynamic field for nodes

[David Marchand <david.marchand@redhat.com>]

Hello Nitin,

On Mon, Apr 7, 2025 at 9:48 AM Nitin Saxena <nsaxena@marvell.com> wrote:
>
> Currently each rte_node registers separate mbuf dynamic fields for their
> own purpose. This leads to wastage of mbuf space as once mbuf get passed
> a particular node, the registered dynamic field(by that node) is no
> longer used.
>
> This patch series adds a global/common mbuf dynamic field which is
> reusable by all the nodes(including out-of-tree nodes). This helps to
> repurpose same mbuf dynamic field for other nodes. It contains two types
> of fields: (a) persistent (b) overloadable.
>
> While persistent fields are those which does not often changes during a
> graph walk such as rx/tx interface, buffer flags etc. Currently there
> are no persistent fields added but they can be added later
>
> Overloadable fields are those which can be overloaded by two adjacent
> nodes. Overloadable fields can be repurposed by other two adjacent nodes.
>
> This patch series also updates ip4/ip6 lookup/rewrite nodes to use
> overlaodable mbuf dynamic fields.
>
> Changes in v4
> - Fix github CI
>
> Changes in v3:
> - Fix CI build error
>
> Changes in v2:
> - removed usage of memzone for saving mbuf dynfield [Stephen]
> - fixed checkpatch issues
> - redefine RTE_NODE_MBUF_OVERLOADABLE_FIELDS_SIZE to 8 byte which are
>   currently in use. Size can increase later based on the usage
>
>
> Nitin Saxena (2):
>   node: add global node mbuf dynfield
>   node: use node mbuf dynfield in ip4 nodes
>
>  doc/api/doxy-api-index.md              |   3 +-
>  doc/guides/rel_notes/release_25_07.rst |   6 ++
>  lib/node/ip4_lookup.c                  |  14 +--
>  lib/node/ip4_rewrite.c                 |  15 ++-
>  lib/node/ip6_lookup.c                  |  15 ++-
>  lib/node/ip6_rewrite.c                 |  14 +--
>  lib/node/meson.build                   |   2 +
>  lib/node/node_mbuf_dynfield.c          |  44 ++++++++
>  lib/node/node_private.h                |  40 +------
>  lib/node/rte_node_mbuf_dynfield.h      | 141 +++++++++++++++++++++++++
>  lib/node/version.map                   |   3 +

I did not review this series but I noticed some version.map update.

When pulling main, you'll notice that exporting symbols must be done
via RTE_EXPORT_*SYMBOL macros now.
No version.map touching anymore, those files are generated at build
time, so developers don't need to care about them.

In lib/node/node_mbuf_dynfield.c, you need to include eal_export.h and add:

+RTE_EXPORT_EXPERIMENTAL_SYMBOL(rte_node_mbuf_dynfield_register, 25.07)
+int rte_node_mbuf_dynfield_register(void)
+{
...


-- 
David Marchand