> -----Original Message----- > From: Olivier Matz [mailto:olivier.matz at 6wind.com] > Sent: Tuesday, July 19, 2016 4:04 PM > To: Richardson, Bruce <bruce.richardson at intel.com> > Cc: dev at dpdk.org; jerin.jacob at caviumnetworks.com; > thomas.monjalon at 6wind.com > Subject: Re: [dpdk-dev] [PATCH] doc: announce ABI change for mbuf > structure > > Hi Bruce, > > On 07/19/2016 04:40 PM, Bruce Richardson wrote: > > On Tue, Jul 19, 2016 at 04:01:15PM +0200, Olivier Matz wrote: > >> For 16.11, the mbuf structure will be modified implying ABI breakage. > >> Some discussions already took place here: > >> http://www.dpdk.org/dev/patchwork/patch/12878/ > >> > >> Signed-off-by: Olivier Matz <olivier.matz at 6wind.com> > >> --- > >> doc/guides/rel_notes/deprecation.rst | 6 ++++++ > >> 1 file changed, 6 insertions(+) > >> > >> diff --git a/doc/guides/rel_notes/deprecation.rst > >> b/doc/guides/rel_notes/deprecation.rst > >> index f502f86..2245bc2 100644 > >> --- a/doc/guides/rel_notes/deprecation.rst > >> +++ b/doc/guides/rel_notes/deprecation.rst > >> @@ -41,3 +41,9 @@ Deprecation Notices > >> * The mempool functions for single/multi producer/consumer are > deprecated and > >> will be removed in 16.11. > >> It is replaced by rte_mempool_generic_get/put functions. > >> + > >> +* ABI changes are planned for 16.11 in the ``rte_mbuf`` structure: > >> +some > >> + fields will be reordered to facilitate the writing of > >> +``data_off``, > >> + ``refcnt``, and ``nb_segs`` in one operation. Indeed, some > >> +platforms > >> + have an overhead if the store address is not naturally aligned. > >> +The > >> + useless ``port`` field will also be removed at the same occasion. > >> -- > > > > Have we fully bottomed out on the mbuf changes. I'm not sure that once > > patches start getting considered for merge, new opinions may come > > forward. For instance, is the "port" field really "useless"? > > > > Would it not be better to put in a less specific deprecation notice? > > What happens if this notice goes in and the final changes are > > different from those called out here? > > Yes, you are right. What about the following text? > > ABI changes are planned for 16.11 in the ``rte_mbuf`` structure: some > fields may be reordered to facilitate the writing of ``data_off``, > ``refcnt``, and ``nb_segs`` in one operation. Indeed, some platforms have > an overhead if the store address is not naturally aligned. The ``port`` > field may also be removed at the same occasion. > Better. Two suggestions: 1. change "Indeed" to "because" and join the sentences. 2. change the last sentence to be even more general: "Other mbuf fields, such as the port field, may be moved or removed as part of this mbuf work".
/Bruce