[dpdk-dev] [PATCH v2] net/octeontx2: avoid per-pkt barrier with multi seg

Jerin Jacob jerinjacobk at gmail.com
Sat Oct 31 14:55:53 CET 2020


On Wed, Oct 28, 2020 at 5:17 PM Nithin Dabilpuram
<ndabilpuram at marvell.com> wrote:
>
> Avoid per-pkt barrier with multi-seg with fast free
> and remove mbuf update to NULL.
>
> Fixes: ce8628c66a22 ("net/octeontx2: fix jumbo frame crash")
> Cc: hkalra at marvell.com
> Cc: stable at dpdk.org
>
> Signed-off-by: Nithin Dabilpuram <ndabilpuram at marvell.com>
> Signed-off-by: Jerin Jacob <jerinj at marvell.com>

Applied to dpdk-next-net-mrvl/for-main. Thanks



> ---
>
> v2:
> - Add fixes tag and also cc stable
>
>  drivers/event/octeontx2/otx2_worker.h | 22 ++++++++--------------
>  drivers/net/octeontx2/otx2_tx.c       |  8 ++++++--
>  drivers/net/octeontx2/otx2_tx.h       | 12 ++++++++----
>  3 files changed, 22 insertions(+), 20 deletions(-)
>
> diff --git a/drivers/event/octeontx2/otx2_worker.h b/drivers/event/octeontx2/otx2_worker.h
> index 4501f4e..3efd3ba 100644
> --- a/drivers/event/octeontx2/otx2_worker.h
> +++ b/drivers/event/octeontx2/otx2_worker.h
> @@ -288,18 +288,12 @@ otx2_ssogws_event_tx(struct otx2_ssogws *ws, struct rte_event ev[],
>
>         /* Perform header writes before barrier for TSO */
>         otx2_nix_xmit_prepare_tso(m, flags);
> -       /* Lets commit any changes in the packet here in case of single seg as
> -        * no further changes to mbuf will be done.
> -        * While for multi seg all mbufs used are set to NULL in
> -        * otx2_nix_prepare_mseg() after preparing the sg list and these changes
> -        * should be committed before LMTST.
> -        * Also in no fast free case some mbuf fields are updated in
> -        * otx2_nix_prefree_seg
> -        * Hence otx2_nix_xmit_submit_lmt_release/otx2_nix_xmit_mseg_one_release
> -        * has store barrier for multiseg.
> +       /* Lets commit any changes in the packet here in case when
> +        * fast free is set as no further changes will be made to mbuf.
> +        * In case of fast free is not set, both otx2_nix_prepare_mseg()
> +        * and otx2_nix_xmit_prepare() has a barrier after refcnt update.
>          */
> -       if (!(flags & NIX_TX_MULTI_SEG_F) &&
> -           !(flags & NIX_TX_OFFLOAD_MBUF_NOFF_F))
> +       if (!(flags & NIX_TX_OFFLOAD_MBUF_NOFF_F))
>                 rte_io_wmb();
>         txq = otx2_ssogws_xtract_meta(m, txq_data);
>         otx2_ssogws_prepare_pkt(txq, m, cmd, flags);
> @@ -311,12 +305,12 @@ otx2_ssogws_event_tx(struct otx2_ssogws *ws, struct rte_event ev[],
>                 if (!ev->sched_type) {
>                         otx2_nix_xmit_mseg_prep_lmt(cmd, txq->lmt_addr, segdw);
>                         otx2_ssogws_head_wait(ws);
> -                       if (otx2_nix_xmit_submit_lmt_release(txq->io_addr) == 0)
> +                       if (otx2_nix_xmit_submit_lmt(txq->io_addr) == 0)
>                                 otx2_nix_xmit_mseg_one(cmd, txq->lmt_addr,
>                                                        txq->io_addr, segdw);
>                 } else {
> -                       otx2_nix_xmit_mseg_one_release(cmd, txq->lmt_addr,
> -                                                      txq->io_addr, segdw);
> +                       otx2_nix_xmit_mseg_one(cmd, txq->lmt_addr,
> +                                              txq->io_addr, segdw);
>                 }
>         } else {
>                 /* Passing no of segdw as 4: HDR + EXT + SG + SMEM */
> diff --git a/drivers/net/octeontx2/otx2_tx.c b/drivers/net/octeontx2/otx2_tx.c
> index 4458d8b..439c46f 100644
> --- a/drivers/net/octeontx2/otx2_tx.c
> +++ b/drivers/net/octeontx2/otx2_tx.c
> @@ -77,11 +77,15 @@ nix_xmit_pkts_mseg(void *tx_queue, struct rte_mbuf **tx_pkts,
>                         otx2_nix_xmit_prepare_tso(tx_pkts[i], flags);
>         }
>
> +       /* Lets commit any changes in the packet here as no further changes
> +        * to the packet will be done unless no fast free is enabled.
> +        */
> +       if (!(flags & NIX_TX_OFFLOAD_MBUF_NOFF_F))
> +               rte_io_wmb();
> +
>         for (i = 0; i < pkts; i++) {
>                 otx2_nix_xmit_prepare(tx_pkts[i], cmd, flags);
>                 segdw = otx2_nix_prepare_mseg(tx_pkts[i], cmd, flags);
> -               /* Lets commit any changes in the packet */
> -               rte_io_wmb();
>                 otx2_nix_xmit_prepare_tstamp(cmd, &txq->cmd[0],
>                                              tx_pkts[i]->ol_flags, segdw,
>                                              flags);
> diff --git a/drivers/net/octeontx2/otx2_tx.h b/drivers/net/octeontx2/otx2_tx.h
> index d6ea3b4..a97b160 100644
> --- a/drivers/net/octeontx2/otx2_tx.h
> +++ b/drivers/net/octeontx2/otx2_tx.h
> @@ -440,13 +440,17 @@ otx2_nix_prepare_mseg(struct rte_mbuf *m, uint64_t *cmd, const uint16_t flags)
>                 sg_u = sg_u | ((uint64_t)m->data_len << (i << 4));
>                 *slist = rte_mbuf_data_iova(m);
>                 /* Set invert df if buffer is not to be freed by H/W */
> -               if (flags & NIX_TX_OFFLOAD_MBUF_NOFF_F)
> +               if (flags & NIX_TX_OFFLOAD_MBUF_NOFF_F) {
>                         sg_u |= (otx2_nix_prefree_seg(m) << (i + 55));
> +                       /* Commit changes to mbuf */
> +                       rte_io_wmb();
> +               }
>                 /* Mark mempool object as "put" since it is freed by NIX */
> -               if (!(sg_u & (1ULL << (i + 55)))) {
> -                       m->next = NULL;
> +#ifdef RTE_LIBRTE_MEMPOOL_DEBUG
> +               if (!(sg_u & (1ULL << (i + 55))))
>                         __mempool_check_cookies(m->pool, (void **)&m, 1, 0);
> -               }
> +               rte_io_wmb();
> +#endif
>                 slist++;
>                 i++;
>                 nb_segs--;
> --
> 2.8.4
>


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