On Fri, Sep 28, 2018 at 05:15:11PM +0100, Tiago Lam wrote:
> From: Mark Kavanagh <[email protected]>
>
> Currently, packets are only copied to a single segment in the function
> dpdk_do_tx_copy(). This could be an issue in the case of jumbo frames,
> particularly when multi-segment mbufs are involved.
>
> This patch calculates the number of segments needed by a packet and
> copies the data to each segment.
>
> A new function, dpdk_buf_alloc(), has also been introduced as a wrapper
> around the nonpmd_mp_mutex to serialise allocations from a non-pmd
> context.
>
> Co-authored-by: Michael Qiu <[email protected]>
> Co-authored-by: Tiago Lam <[email protected]>
>
> Signed-off-by: Mark Kavanagh <[email protected]>
> Signed-off-by: Michael Qiu <[email protected]>
> Signed-off-by: Tiago Lam <[email protected]>
> Acked-by: Eelco Chaudron <[email protected]>
> ---
> lib/netdev-dpdk.c | 91
> +++++++++++++++++++++++++++++++++++++++++++++++++------
> 1 file changed, 82 insertions(+), 9 deletions(-)
>
> diff --git a/lib/netdev-dpdk.c b/lib/netdev-dpdk.c
> index 8484239..e58e7ac 100644
> --- a/lib/netdev-dpdk.c
> +++ b/lib/netdev-dpdk.c
> @@ -552,6 +552,27 @@ dpdk_rte_mzalloc(size_t sz)
> return rte_zmalloc(OVS_VPORT_DPDK, sz, OVS_CACHE_LINE_SIZE);
> }
>
> +static struct rte_mbuf *
> +dpdk_buf_alloc(struct rte_mempool *mp)
> +{
> + struct rte_mbuf *mbuf = NULL;
> +
> + /* If non-pmd we need to lock on nonpmd_mp_mutex mutex */
> + if (!dpdk_thread_is_pmd()) {
> + ovs_mutex_lock(&nonpmd_mp_mutex);
> +
> + mbuf = rte_pktmbuf_alloc(mp);
> +
> + ovs_mutex_unlock(&nonpmd_mp_mutex);
> +
> + return mbuf;
> + }
> +
> + mbuf = rte_pktmbuf_alloc(mp);
> +
> + return mbuf;
> +}
What about:
if (dpdk_thread_is_pmd()) {
mbuf = rte_pktmbuf_alloc(mp);
} else {
ovs_mutex_lock(&nonpmd_mp_mutex);
mbuf = rte_pktmbuf_alloc(mp);
ovs_mutex_unlock(&nonpmd_mp_mutex);
}
return mbuf;
> +
> void
> free_dpdk_buf(struct dp_packet *packet)
> {
> @@ -2316,6 +2337,56 @@ out:
> }
> }
>
> +static int
> +dpdk_copy_dp_packet_to_mbuf(struct dp_packet *packet, struct rte_mbuf **head,
> + struct rte_mempool *mp)
> +{
> + struct rte_mbuf *mbuf, *fmbuf;
> + uint16_t max_data_len;
> + uint32_t nb_segs = 0;
> + uint32_t size = 0;
> +
> + /* We will need the whole data for copying below */
> + if (!dp_packet_is_linear(packet)) {
> + dp_packet_linearize(packet);
> + }
> +
> + /* Allocate first mbuf to know the size of data available */
> + fmbuf = mbuf = *head = dpdk_buf_alloc(mp);
> + if (OVS_UNLIKELY(!mbuf)) {
> + return ENOMEM;
> + }
> +
> + size = dp_packet_size(packet);
> +
> + /* All new allocated mbuf's max data len is the same */
> + max_data_len = mbuf->buf_len - mbuf->data_off;
> +
> + /* Calculate # of output mbufs. */
> + nb_segs = size / max_data_len;
> + if (size % max_data_len) {
> + nb_segs = nb_segs + 1;
> + }
> +
> + /* Allocate additional mbufs, less the one alredy allocated above */
> + for (int i = 1; i < nb_segs; i++) {
> + mbuf->next = dpdk_buf_alloc(mp);
> + if (!mbuf->next) {
> + free_dpdk_buf(CONTAINER_OF(fmbuf, struct dp_packet, mbuf));
> + fmbuf = NULL;
> + return ENOMEM;
> + }
> + mbuf = mbuf->next;
> + }
> +
> + fmbuf->nb_segs = nb_segs;
> + fmbuf->pkt_len = size;
> +
> + dp_packet_mbuf_write(fmbuf, 0, size, dp_packet_data(packet));
> +
> + return 0;
> +}
> +
> /* Tx function. Transmit packets indefinitely */
> static void
> dpdk_do_tx_copy(struct netdev *netdev, int qid, struct dp_packet_batch
> *batch)
> @@ -2332,6 +2403,7 @@ dpdk_do_tx_copy(struct netdev *netdev, int qid, struct
> dp_packet_batch *batch)
> struct rte_mbuf *pkts[PKT_ARRAY_SIZE];
> uint32_t cnt = batch_cnt;
> uint32_t dropped = 0;
> + uint32_t i;
>
> if (dev->type != DPDK_DEV_VHOST) {
> /* Check if QoS has been configured for this netdev. */
> @@ -2342,28 +2414,29 @@ dpdk_do_tx_copy(struct netdev *netdev, int qid,
> struct dp_packet_batch *batch)
>
> uint32_t txcnt = 0;
>
> - for (uint32_t i = 0; i < cnt; i++) {
> + for (i = 0; i < cnt; i++) {
> struct dp_packet *packet = batch->packets[i];
> uint32_t size = dp_packet_size(packet);
> + int err = 0;
>
> if (OVS_UNLIKELY(size > dev->max_packet_len)) {
> VLOG_WARN_RL(&rl, "Too big size %u max_packet_len %d",
> size, dev->max_packet_len);
> -
> dropped++;
> continue;
> }
>
> - pkts[txcnt] = rte_pktmbuf_alloc(dev->dpdk_mp->mp);
> - if (OVS_UNLIKELY(!pkts[txcnt])) {
> + err = dpdk_copy_dp_packet_to_mbuf(packet, &pkts[txcnt],
> + dev->dpdk_mp->mp);
> + if (err != 0) {
> + if (err == ENOMEM) {
> + VLOG_ERR_RL(&rl, "Failed to alloc mbufs! %u packets dropped",
> + cnt - i);
> + }
> +
> dropped += cnt - i;
> break;
> }
> -
> - /* We have to do a copy for now */
> - memcpy(rte_pktmbuf_mtod(pkts[txcnt], void *),
> - dp_packet_data(packet), size);
> - dp_packet_set_size((struct dp_packet *)pkts[txcnt], size);
> dp_packet_copy_mbuf_flags((struct dp_packet *)pkts[txcnt], packet);
>
> txcnt++;
> --
> 2.7.4
>
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--
Flavio
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