From: Eric Dumazet <eduma...@google.com>
UDP busy polling is restricted to connected UDP sockets.
This is because sk_busy_loop() only takes care of one NAPI context.
There are cases where it could be extended.
1) Some hosts receive traffic on a single NIC, with one RX queue.
2) Some applications use SO_REUSEPORT and associated BPF filter
to split the incoming traffic on one UDP socket per RX
queue/thread/cpu
3) Some UDP sockets are used to send/receive traffic for one flow, but
they do not bother with connect()
This patch records the napi_id of first received skb, giving more
reach to busy polling.
Tested:
lpaa23:~# echo 70 >/proc/sys/net/core/busy_read
lpaa24:~# echo 70 >/proc/sys/net/core/busy_read
lpaa23:~# for f in `seq 1 10`; do ./super_netperf 1 -H lpaa24 -t UDP_RR -l 5;
done
Before patch :
27867 28870 37324 41060 41215
36764 36838 44455 41282 43843
After patch :
73920 73213 70147 74845 71697
68315 68028 75219 70082 73707
Signed-off-by: Eric Dumazet <eduma...@google.com>
Cc: Willem de Bruijn <will...@google.com>
---
include/net/busy_poll.h | 28 +++++++++++++++++++---------
net/ipv4/udp.c | 2 ++
net/ipv6/udp.c | 2 ++
3 files changed, 23 insertions(+), 9 deletions(-)
diff --git a/include/net/busy_poll.h b/include/net/busy_poll.h
index
2fbeb1313c0f4f78ac82ddf6c18d1016a901f99a..34c57a0ec040a58f09b12e3878f534433dc30015
100644
--- a/include/net/busy_poll.h
+++ b/include/net/busy_poll.h
@@ -81,11 +81,6 @@ static inline void skb_mark_napi_id(struct sk_buff *skb,
skb->napi_id = napi->napi_id;
}
-/* used in the protocol hanlder to propagate the napi_id to the socket */
-static inline void sk_mark_napi_id(struct sock *sk, struct sk_buff *skb)
-{
- sk->sk_napi_id = skb->napi_id;
-}
#else /* CONFIG_NET_RX_BUSY_POLL */
static inline unsigned long net_busy_loop_on(void)
@@ -108,10 +103,6 @@ static inline void skb_mark_napi_id(struct sk_buff *skb,
{
}
-static inline void sk_mark_napi_id(struct sock *sk, struct sk_buff *skb)
-{
-}
-
static inline bool busy_loop_timeout(unsigned long end_time)
{
return true;
@@ -123,4 +114,23 @@ static inline bool sk_busy_loop(struct sock *sk, int
nonblock)
}
#endif /* CONFIG_NET_RX_BUSY_POLL */
+
+/* used in the protocol hanlder to propagate the napi_id to the socket */
+static inline void sk_mark_napi_id(struct sock *sk, const struct sk_buff *skb)
+{
+#ifdef CONFIG_NET_RX_BUSY_POLL
+ sk->sk_napi_id = skb->napi_id;
+#endif
+}
+
+/* variant used for unconnected sockets */
+static inline void sk_mark_napi_id_once(struct sock *sk,
+ const struct sk_buff *skb)
+{
+#ifdef CONFIG_NET_RX_BUSY_POLL
+ if (!sk->sk_napi_id)
+ sk->sk_napi_id = skb->napi_id;
+#endif
+}
+
#endif /* _LINUX_NET_BUSY_POLL_H */
diff --git a/net/ipv4/udp.c b/net/ipv4/udp.c
index
9ae7c63a8b131f56a3c05e00a8f7d106a0362c54..e1fc0116e8d59d8185670c6e55d1219bde55610d
100644
--- a/net/ipv4/udp.c
+++ b/net/ipv4/udp.c
@@ -1569,6 +1569,8 @@ static int __udp_queue_rcv_skb(struct sock *sk, struct
sk_buff *skb)
sock_rps_save_rxhash(sk, skb);
sk_mark_napi_id(sk, skb);
sk_incoming_cpu_update(sk);
+ } else {
+ sk_mark_napi_id_once(sk, skb);
}
rc = __udp_enqueue_schedule_skb(sk, skb);
diff --git a/net/ipv6/udp.c b/net/ipv6/udp.c
index
86a8cacd333b64f40acc7350a45213cb422a9c1a..4f99417d9b401f2a65c7828e7d6b86d1d6161794
100644
--- a/net/ipv6/udp.c
+++ b/net/ipv6/udp.c
@@ -519,6 +519,8 @@ static int __udpv6_queue_rcv_skb(struct sock *sk, struct
sk_buff *skb)
sock_rps_save_rxhash(sk, skb);
sk_mark_napi_id(sk, skb);
sk_incoming_cpu_update(sk);
+ } else {
+ sk_mark_napi_id_once(sk, skb);
}
rc = __udp_enqueue_schedule_skb(sk, skb);
