Didn't notice that. Will fix it in v2. Thanks!
> -----Original Message-----
> From: Gavin Hu (Arm Technology China) [mailto:[email protected]]
> Sent: Saturday, December 14, 2019 23:30
> To: Li, Xiaoyun <[email protected]>; Wu, Jingjing <[email protected]>
> Cc: [email protected]; [email protected]; nd <[email protected]>
> Subject: RE: [dpdk-dev] [PATCH] raw/ntb: fix write memory barrier issue
>
> Hi Xiaoyun,
>
> > -----Original Message-----
> > From: dev <[email protected]> On Behalf Of Xiaoyun Li
> > Sent: Wednesday, December 4, 2019 11:19 PM
> > To: [email protected]
> > Cc: [email protected]; Xiaoyun Li <[email protected]>; [email protected]
> > Subject: [dpdk-dev] [PATCH] raw/ntb: fix write memory barrier issue
> >
> > All buffers and ring info should be written before tail register update.
> > This patch relocates the write memory barrier before updating tail register
> > to avoid potential issues.
> >
> > Fixes: 11b5c7daf019 ("raw/ntb: add enqueue and dequeue functions")
> > Cc: [email protected]
> >
> > Signed-off-by: Xiaoyun Li <[email protected]>
> > ---
> > drivers/raw/ntb/ntb.c | 4 ++--
> > 1 file changed, 2 insertions(+), 2 deletions(-)
> >
> > diff --git a/drivers/raw/ntb/ntb.c b/drivers/raw/ntb/ntb.c
> > index ad7f6abfd..dd0b72f8c 100644
> > --- a/drivers/raw/ntb/ntb.c
> > +++ b/drivers/raw/ntb/ntb.c
> > @@ -683,8 +683,8 @@ ntb_enqueue_bufs(struct rte_rawdev *dev,
> > sizeof(struct ntb_used) * nb1);
> > rte_memcpy(txq->tx_used_ring, tx_used + nb1,
> > sizeof(struct ntb_used) * nb2);
> > - *txq->used_cnt = txq->last_used;
> > rte_wmb();
> > + *txq->used_cnt = txq->last_used;
> I am ok with the re-location of the barrier, but why not the rte_io_wmb
> instead
> of rte_wmb?
> Rte_io_wmb is sufficient to guarantee the preceding stores are visible to the
> device, rte_wmb is overkill.
> https://code.dpdk.org/dpdk/latest/source/lib/librte_eal/common/include/gener
> ic/rte_atomic.h#L92
> >
> > /* update queue stats */
> > hw->ntb_xstats[NTB_TX_BYTES_ID + off] += bytes;
> > @@ -789,8 +789,8 @@ ntb_dequeue_bufs(struct rte_rawdev *dev,
> > sizeof(struct ntb_desc) * nb1);
> > rte_memcpy(rxq->rx_desc_ring, rx_desc + nb1,
> > sizeof(struct ntb_desc) * nb2);
> > - *rxq->avail_cnt = rxq->last_avail;
> > rte_wmb();
> > + *rxq->avail_cnt = rxq->last_avail;
> >
> > /* update queue stats */
> > off = NTB_XSTATS_NUM * ((size_t)context + 1);
> > --
> > 2.17.1
