[dpdk-dev] [PATCH v2 6/8] mbuf: use 2 bytes for port and nb segments

[Morten Brørup]

> -----Original Message-----
> From: dev [mailto:dev-bounces at dpdk.org] On Behalf Of Olivier Matz
> Sent: Monday, July 10, 2017 10:00 AM
> Subject: Re: [dpdk-dev] [PATCH v2 6/8] mbuf: use 2 bytes for port and
> nb segments
> 
> Hi,
> 
> On Tue, 4 Jul 2017 07:54:23 +0000, "Wang, Zhihong"
> <zhihong.wang at intel.com> wrote:
> > > -----Original Message-----
> > > From: dev [mailto:dev-bounces at dpdk.org] On Behalf Of Olivier MATZ
> > > Sent: Tuesday, April 18, 2017 9:03 PM
> > > To: Yuanhan Liu <yuanhan.liu at linux.intel.com>
> > >
> > > Hi Yuanhan,
> > >
> > > On Thu, 6 Apr 2017 13:45:23 +0800, Yuanhan Liu
> > > <yuanhan.liu at linux.intel.com> wrote:
> > > > Hi Olivier,
> > > >
> > > > On Tue, Apr 04, 2017 at 06:28:05PM +0200, Olivier Matz wrote:
> > > > > Change the size of m->port and m->nb_segs to 16 bits.
> > > >
> > > > But all the ethdev APIs are still using 8 bits. 16 bits won't
> > > > really take effect without updating those APIs. Any plans?
> > > >
> > > > 	--yliu
> > >
> > > Yes, there is some work in ethdev, drivers and in example apps to
> > > make the change effective. I think we could define a specific type
> > > for a port number, maybe rte_eth_port_num_t. Using this type could
> > > be a first step (for 17.08) before switching to 16 bits (17.11?).
> > >
> > > I'll do the change and send a rfc.
> >
> > Ping ;) Is this still in your plan?
> >
> 
> Sorry, I don't think I will have time to work on this issue in the
> coming weeks. If you plan to do it, I will be happy to help with
> reviews and comments.
> 
> As I said in a previous message, I think a good first step would be to
> introduce a typedef for the port number: rte_eth_port_num_t.
> It can still be uint8_t for now, and can be switched to 16 bits in one
> step when everyone uses this new type.
> 
> Olivier

I think that DPDK follows the Linux tradition of exposing the variable types, as opposed to hiding them behind typedefs. This has the unfortunate consequence that when a variable type changes, it has to be changed everywhere.

Introducing a rte_eth_port_num_t will require changing the same files at the same locations everywhere, so not even as a temporary solution will it be beneficial.


Med venlig hilsen / kind regards
- Morten Brørup