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dpif-netdev: Upcall: Remove an extra memcpy of packet data.

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When a bridge of datatype type netdev receives a packet, it
copies the packet from the NIC to a buffer in userspace.
Currently, when making an upcall, the packet is again copied
to the upcall's buffer. However, this extra copy is not
necessary when the datapath exists in userspace as the upcall
can directly access the packet data.

This patch eliminates this extra copy of the packet data in
most cases. In cases where the packet may still be used later
by callers of dp_netdev_execute_actions, making a copy of the
packet data is still necessary.

This patch also adds a dpdk_buf field to 'struct ofpbuf' when
using DPDK. This field holds a pointer to the allocated DPDK
buffer in the rte_mempool. Thus, an upcall packet ofpbuf
allocated on the stack can now share data and free memory of
a rte_mempool allocated ofpbuf.

Signed-off-by: Ryan Wilson <wryan@nicira.com>
Acked-by: Jarno Rajahalme <jrajahalme@nicira.com>
Acked-by: Pravin B Shelar <pshelar@nicira.com>
This commit is contained in:
Ryan Wilson
2014-06-04 13:49:06 -07:00
committed by Pravin B Shelar
parent d221ffa1e1
commit 143859ec63
4 changed files with 19 additions and 12 deletions
Download Patch File Download Diff File Expand all files Collapse all files

15
lib/dpif-netdev.c
View File

@@ -2024,7 +2024,6 @@ dp_netdev_input(struct dp_netdev *dp, struct ofpbuf *packet,
miniflow_hash_5tuple(&key.flow, 0)
% dp->n_handlers,
DPIF_UC_MISS, &key.flow, NULL);
ofpbuf_delete(packet);
}
}
@@ -2063,7 +2062,6 @@ dp_netdev_output_userspace(struct dp_netdev *dp, struct ofpbuf *packet,
if (userdata) {
buf_size += NLA_ALIGN(userdata->nla_len);
}
buf_size += ofpbuf_size(packet);
ofpbuf_init(buf, buf_size);
/* Put ODP flow. */
@@ -2078,15 +2076,14 @@ dp_netdev_output_userspace(struct dp_netdev *dp, struct ofpbuf *packet,
NLA_ALIGN(userdata->nla_len));
}
ofpbuf_set_data(&upcall->packet,
ofpbuf_put(buf, ofpbuf_data(packet), ofpbuf_size(packet)));
ofpbuf_set_size(&upcall->packet, ofpbuf_size(packet));
upcall->packet = *packet;
seq_change(q->seq);
error = 0;
} else {
dp_netdev_count_packet(dp, DP_STAT_LOST);
ofpbuf_delete(packet);
error = ENOBUFS;
}
ovs_mutex_unlock(&q->mutex);
@@ -2120,19 +2117,17 @@ dp_execute_cb(void *aux_, struct ofpbuf *packet,
break;
case OVS_ACTION_ATTR_USERSPACE: {
struct ofpbuf *userspace_packet;
const struct nlattr *userdata;
userdata = nl_attr_find_nested(a, OVS_USERSPACE_ATTR_USERDATA);
userspace_packet = may_steal ? packet : ofpbuf_clone(packet);
dp_netdev_output_userspace(aux->dp, packet,
dp_netdev_output_userspace(aux->dp, userspace_packet,
miniflow_hash_5tuple(aux->key, 0)
% aux->dp->n_handlers,
DPIF_UC_ACTION, aux->key,
userdata);
if (may_steal) {
ofpbuf_delete(packet);
}
break;
}

2
lib/netdev-dpdk.c
View File

@@ -205,7 +205,7 @@ dpdk_rte_mzalloc(size_t sz)
void
free_dpdk_buf(struct ofpbuf *b)
{
struct rte_mbuf *pkt = (struct rte_mbuf *) b;
struct rte_mbuf *pkt = (struct rte_mbuf *) b->dpdk_buf;
rte_mempool_put(pkt->pool, pkt);
}

11
lib/ofpbuf.c
View File

@@ -117,6 +117,9 @@ void
ofpbuf_init_dpdk(struct ofpbuf *b, size_t allocated)
{
ofpbuf_init__(b, allocated, OFPBUF_DPDK);
#ifdef DPDK_NETDEV
b->dpdk_buf = b;
#endif
}
/* Initializes 'b' as an empty ofpbuf with an initial capacity of 'size'
@@ -134,8 +137,14 @@ ofpbuf_uninit(struct ofpbuf *b)
if (b) {
if (b->source == OFPBUF_MALLOC) {
free(ofpbuf_base(b));
} else if (b->source == OFPBUF_DPDK) {
#ifdef DPDK_NETDEV
ovs_assert(b != b->dpdk_buf);
free_dpdk_buf(b);
#else
ovs_assert(b->source != OFPBUF_DPDK);
#endif
}
ovs_assert(b->source != OFPBUF_DPDK);
}
}

3
lib/ofpbuf.h
View File

@@ -59,6 +59,7 @@ enum OVS_PACKED_ENUM ofpbuf_source {
struct ofpbuf {
#ifdef DPDK_NETDEV
struct rte_mbuf mbuf; /* DPDK mbuf */
void *dpdk_buf; /* First byte of allocated DPDK buffer. */
#else
void *base_; /* First byte of allocated space. */
void *data_; /* First byte actually in use. */
@@ -354,6 +355,8 @@ static inline const void *ofpbuf_get_icmp_payload(const struct ofpbuf *b)
}
#ifdef DPDK_NETDEV
BUILD_ASSERT_DECL(offsetof(struct ofpbuf, mbuf) == 0);
static inline void * ofpbuf_data(const struct ofpbuf *b)
{
return b->mbuf.pkt.data;