Re: [dpdk-dev] [PATCH 07/13] mbuf: use macros only to access the mbuf metadata

[Olivier MATZ <olivier.matz@6wind.com>]

Hi Bruce,

On 09/10/2014 05:09 PM, Bruce Richardson wrote:
>> Just one question: why not removing RTE_MBUF_METADATA*() macros?
>> I'd just provide one macro that gives a (void*) to the first byte
>> after the mbuf structure.
>>
>> The format of the metadata is up to the application, that usually
>> casts (m + 1) into a private structure, making the macros not very
>> useful. I suggest to move these macros outside rte_mbuf.h, in the
>> application-specific or library-specific header, what do you think?
>>
>
> Things look to work if I just move the definitions en-masse into
> rte_port.h. Is that the sort of change you would be thinking of?
> I was wondering about replacing the typed macros here with a
> generic one to access just beyond the definition of the mbuf
> structure, but on further thought, I believe that using the
> buf_addr pointer in the mbuf data structure is probably enough
> for most applications. [An alternative to moving the definitions
> into rte_port.h is to move them into rte_table.h and having
> port_frag.c use the buf_addr pointer instead of a macro to get at
> the metadata. All other references to the macros apart from two
> in that port file, are in the tables or in apps that use the
> tables lib.]
> What do you think?

Yes, moving the macros in rte_port.h looks good to me, since
the libraries using rte_ports are the users of this specific
metadata format.

Thanks!
Olivier