> -----Original Message----- > From: dev [mailto:dev-bounces at dpdk.org] On Behalf Of Bruce Richardson > Sent: Thursday, December 04, 2014 2:40 PM > To: Jean-Mickael Guerin > Cc: dev at dpdk.org > Subject: Re: [dpdk-dev] [PATCH 1/2] ixgbe: fix setup of mbuf initializer > template > > On Thu, Dec 04, 2014 at 03:26:20PM +0100, Jean-Mickael Guerin wrote: > > Add a compiler barrier to make sure all fields covered by > > the marker rearm_data are assigned before the read. > > > > Signed-off-by: Jean-Mickael Guerin <jean-mickael.guerin at 6wind.com> > > Acked-by: David Marchand <david.marchand at 6wind.com> > > Fixes: 0ff3324da2 ("ixgbe: rework vector pmd following mbuf changes") > > Acked-by: Bruce Richardson <bruce.richardson at intel.com> > > > --- > > lib/librte_pmd_ixgbe/ixgbe_rxtx_vec.c | 3 +++ > > 1 file changed, 3 insertions(+) > > > > diff --git a/lib/librte_pmd_ixgbe/ixgbe_rxtx_vec.c > > b/lib/librte_pmd_ixgbe/ixgbe_rxtx_vec.c > > index 579bc46..c1b5a78 100644 > > --- a/lib/librte_pmd_ixgbe/ixgbe_rxtx_vec.c > > +++ b/lib/librte_pmd_ixgbe/ixgbe_rxtx_vec.c > > @@ -739,6 +739,9 @@ ixgbe_rxq_vec_setup(struct igb_rx_queue *rxq) > > mb_def.buf_len = rxq->mb_pool->elt_size - sizeof(struct rte_mbuf); > > mb_def.port = rxq->port_id; > > rte_mbuf_refcnt_set(&mb_def, 1); > > + > > + /* prevent compiler reordering: rearm_data covers previous fields */ > > + rte_compiler_barrier(); > > rxq->mbuf_initializer = *((uint64_t *)&mb_def.rearm_data); > > return 0; > > } > > --
Hmm, can someone explain to me why do we need a compiler barrier here? Konstantin > > 2.1.3 > >
