[ovs-dev] [PATCH v8 10/14] netdev-dpdk: copy large packet to multi-seg. mbufs
Tiago Lam
tiago.lam at intel.com
Mon Aug 20 17:44:31 UTC 2018
From: Mark Kavanagh <mark.b.kavanagh at intel.com>
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 <qiudayu at chinac.com>
Co-authored-by: Tiago Lam <tiago.lam at intel.com>
Signed-off-by: Mark Kavanagh <mark.b.kavanagh at intel.com>
Signed-off-by: Michael Qiu <qiudayu at chinac.com>
Signed-off-by: Tiago Lam <tiago.lam at intel.com>
Acked-by: Eelco Chaudron <echaudro at redhat.com>
---
lib/netdev-dpdk.c | 84 +++++++++++++++++++++++++++++++++++++++++++++++++------
1 file changed, 75 insertions(+), 9 deletions(-)
diff --git a/lib/netdev-dpdk.c b/lib/netdev-dpdk.c
index e005d00..e2df825 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;
+}
+
void
free_dpdk_buf(struct dp_packet *packet)
{
@@ -2316,6 +2337,49 @@ 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;
+ uint32_t size = dp_packet_size(packet);
+ uint16_t max_data_len;
+ uint32_t nb_segs = 0;
+
+ /* Allocate first mbuf to know the size of data available */
+ fmbuf = mbuf = *head = dpdk_buf_alloc(mp);
+ if (OVS_UNLIKELY(!mbuf)) {
+ return ENOMEM;
+ }
+
+ /* 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 +2396,7 @@ 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 +2407,29 @@ 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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