Re: [EXTERNAL] Re: [PATCH 1/2] node: add global node mbuf dynfield

[Stephen Hemminger <stephen@networkplumber.org>]

On Fri, 4 Apr 2025 08:11:07 +0000
Pavan Nikhilesh Bhagavatula <pbhagavatula@marvell.com> wrote:

> > Hi Stephen,
> > 
> > Thanks for commenting. See response inline.
> > 
> > Regards,
> > Nitin
> > 
> > On Tue, Apr 1, 2025 at 7:45 PM Stephen Hemminger
> > <stephen@networkplumber.org> wrote:  
> > >
> > > On Tue, 1 Apr 2025 09:50:46 +0530
> > > Nitin Saxena <nsaxena@marvell.com> wrote:
> > >  
> > > > +int rte_node_mbuf_dynfield_register(void)
> > > > +{
> > > > +     struct node_mbuf_dynfield_mz *f = NULL;
> > > > +     const struct rte_memzone *mz = NULL;
> > > > +     int dyn_offset;
> > > > +
> > > > +     RTE_BUILD_BUG_ON(sizeof(rte_node_mbuf_dynfield_t) <  
> > RTE_NODE_MBUF_DYNFIELD_SIZE);  
> > > > +     RTE_BUILD_BUG_ON(sizeof(rte_node_mbuf_overload_fields_t) <
> > > > +                      RTE_NODE_MBUF_OVERLOADABLE_FIELDS_SIZE);
> > > > +
> > > > +     mz =  
> > rte_memzone_lookup(NODE_MBUF_DYNFIELD_MEMZONE_NAME);  
> > >
> > > Seems wasteful to have a whole memzone for this, the data is small.
> > > Is there a reason it could not just be a global variable like timestamp.
> > >  
> > Replaced usage of memzone with global variable in v2  
> 
> We need to use memzone to share the offset between primary and secondary
> processes I don’t see any other way.


Normally secondary just uses dynamic field lookup to find the offset.