[net-next PATCH v3 3/5] net: Enable Tx queue selection based on Rx queues

[Amritha Nambiar <amritha.nambiar@intel.com>]

This patch adds support to pick Tx queue based on the Rx queue(s) map
configuration set by the admin through the sysfs attribute
for each Tx queue. If the user configuration for receive queue(s) map
does not apply, then the Tx queue selection falls back to CPU(s) map
based selection and finally to hashing.

Signed-off-by: Amritha Nambiar <amritha.nambiar@intel.com>
Signed-off-by: Sridhar Samudrala <sridhar.samudrala@intel.com>
---
 include/net/busy_poll.h |    3 ++
 include/net/sock.h      |   14 +++++++++++
 net/core/dev.c          |   60 ++++++++++++++++++++++++++++++++---------------
 net/core/sock.c         |    4 +++
 net/ipv4/tcp_input.c    |    3 ++
 5 files changed, 65 insertions(+), 19 deletions(-)

diff --git a/include/net/busy_poll.h b/include/net/busy_poll.h
index 71c72a9..fc4fb68 100644
--- a/include/net/busy_poll.h
+++ b/include/net/busy_poll.h
@@ -136,6 +136,9 @@ 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
+#ifdef CONFIG_XPS
+	sk->sk_rx_queue_mapping = skb_get_rx_queue(skb);
+#endif
 }
 
 /* variant used for unconnected sockets */
diff --git a/include/net/sock.h b/include/net/sock.h
index 4f7c584..12313653 100644
--- a/include/net/sock.h
+++ b/include/net/sock.h
@@ -139,6 +139,7 @@ typedef __u64 __bitwise __addrpair;
  *	@skc_node: main hash linkage for various protocol lookup tables
  *	@skc_nulls_node: main hash linkage for TCP/UDP/UDP-Lite protocol
  *	@skc_tx_queue_mapping: tx queue number for this connection
+ *	@skc_rx_queue_mapping: rx queue number for this connection
  *	@skc_flags: place holder for sk_flags
  *		%SO_LINGER (l_onoff), %SO_BROADCAST, %SO_KEEPALIVE,
  *		%SO_OOBINLINE settings, %SO_TIMESTAMPING settings
@@ -215,6 +216,9 @@ struct sock_common {
 		struct hlist_nulls_node skc_nulls_node;
 	};
 	int			skc_tx_queue_mapping;
+#ifdef CONFIG_XPS
+	int			skc_rx_queue_mapping;
+#endif
 	union {
 		int		skc_incoming_cpu;
 		u32		skc_rcv_wnd;
@@ -326,6 +330,9 @@ struct sock {
 #define sk_nulls_node		__sk_common.skc_nulls_node
 #define sk_refcnt		__sk_common.skc_refcnt
 #define sk_tx_queue_mapping	__sk_common.skc_tx_queue_mapping
+#ifdef CONFIG_XPS
+#define sk_rx_queue_mapping	__sk_common.skc_rx_queue_mapping
+#endif
 
 #define sk_dontcopy_begin	__sk_common.skc_dontcopy_begin
 #define sk_dontcopy_end		__sk_common.skc_dontcopy_end
@@ -1696,6 +1703,13 @@ static inline int sk_tx_queue_get(const struct sock *sk)
 	return sk ? sk->sk_tx_queue_mapping : -1;
 }
 
+static inline void sk_mark_rx_queue(struct sock *sk, struct sk_buff *skb)
+{
+#ifdef CONFIG_XPS
+	sk->sk_rx_queue_mapping = skb_get_rx_queue(skb);
+#endif
+}
+
 static inline void sk_set_socket(struct sock *sk, struct socket *sock)
 {
 	sk_tx_queue_clear(sk);
diff --git a/net/core/dev.c b/net/core/dev.c
index bba755f..1880e6c 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -3479,36 +3479,58 @@ sch_handle_egress(struct sk_buff *skb, int *ret, struct net_device *dev)
 }
 #endif /* CONFIG_NET_EGRESS */
 
-static inline int get_xps_queue(struct net_device *dev, struct sk_buff *skb)
+#ifdef CONFIG_XPS
+static int __get_xps_queue_idx(struct net_device *dev, struct sk_buff *skb,
+			       struct xps_dev_maps *dev_maps, unsigned int tci)
+{
+	struct xps_map *map;
+	int queue_index = -1;
+
+	if (dev->num_tc) {
+		tci *= dev->num_tc;
+		tci += netdev_get_prio_tc_map(dev, skb->priority);
+	}
+
+	map = rcu_dereference(dev_maps->attr_map[tci]);
+	if (map) {
+		if (map->len == 1)
+			queue_index = map->queues[0];
+		else
+			queue_index = map->queues[reciprocal_scale(
+						skb_get_hash(skb), map->len)];
+		if (unlikely(queue_index >= dev->real_num_tx_queues))
+			queue_index = -1;
+	}
+	return queue_index;
+}
+#endif
+
+static int get_xps_queue(struct net_device *dev, struct sk_buff *skb)
 {
 #ifdef CONFIG_XPS
 	struct xps_dev_maps *dev_maps;
-	struct xps_map *map;
+	struct sock *sk = skb->sk;
 	int queue_index = -1;
+	unsigned int tci = 0;
 
 	if (!static_key_false(&xps_needed))
 		return -1;
 
+	if (sk && sk->sk_rx_queue_mapping <= dev->num_rx_queues)
+		tci = sk->sk_rx_queue_mapping;
+
 	rcu_read_lock();
-	dev_maps = rcu_dereference(dev->xps_cpus_map);
-	if (dev_maps) {
-		unsigned int tci = skb->sender_cpu - 1;
+	dev_maps = rcu_dereference(dev->xps_rxqs_map);
+	if (dev_maps)
+		queue_index = __get_xps_queue_idx(dev, skb, dev_maps, tci);
 
-		if (dev->num_tc) {
-			tci *= dev->num_tc;
-			tci += netdev_get_prio_tc_map(dev, skb->priority);
-		}
 
-		map = rcu_dereference(dev_maps->attr_map[tci]);
-		if (map) {
-			if (map->len == 1)
-				queue_index = map->queues[0];
-			else
-				queue_index = map->queues[reciprocal_scale(skb_get_hash(skb),
-									   map->len)];
-			if (unlikely(queue_index >= dev->real_num_tx_queues))
-				queue_index = -1;
-		}
+	if (queue_index < 0) {
+		tci = skb->sender_cpu - 1;
+		dev_maps = rcu_dereference(dev->xps_cpus_map);
+		if (dev_maps)
+			queue_index = __get_xps_queue_idx(dev, skb, dev_maps,
+							  tci);
 	}
 	rcu_read_unlock();
 
diff --git a/net/core/sock.c b/net/core/sock.c
index 435a0ba..3c10d31 100644
--- a/net/core/sock.c
+++ b/net/core/sock.c
@@ -2824,6 +2824,10 @@ void sock_init_data(struct socket *sock, struct sock *sk)
 	sk->sk_pacing_rate = ~0U;
 	sk->sk_pacing_shift = 10;
 	sk->sk_incoming_cpu = -1;
+
+#ifdef CONFIG_XPS
+	sk->sk_rx_queue_mapping = -1;
+#endif
 	/*
 	 * Before updating sk_refcnt, we must commit prior changes to memory
 	 * (Documentation/RCU/rculist_nulls.txt for details)
diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c
index d5ffb57..cc69f75 100644
--- a/net/ipv4/tcp_input.c
+++ b/net/ipv4/tcp_input.c
@@ -78,6 +78,7 @@
 #include <linux/errqueue.h>
 #include <trace/events/tcp.h>
 #include <linux/static_key.h>
+#include <net/busy_poll.h>
 
 int sysctl_tcp_max_orphans __read_mostly = NR_FILE;
 
@@ -5574,6 +5575,7 @@ void tcp_finish_connect(struct sock *sk, struct sk_buff *skb)
 	if (skb) {
 		icsk->icsk_af_ops->sk_rx_dst_set(sk, skb);
 		security_inet_conn_established(sk, skb);
+		sk_mark_napi_id(sk, skb);
 	}
 
 	tcp_init_transfer(sk, BPF_SOCK_OPS_ACTIVE_ESTABLISHED_CB);
@@ -6402,6 +6404,7 @@ int tcp_conn_request(struct request_sock_ops *rsk_ops,
 	tcp_rsk(req)->snt_isn = isn;
 	tcp_rsk(req)->txhash = net_tx_rndhash();
 	tcp_openreq_init_rwin(req, sk, dst);
+	sk_mark_rx_queue(req_to_sk(req), skb);
 	if (!want_cookie) {
 		tcp_reqsk_record_syn(sk, req, skb);
 		fastopen_sk = tcp_try_fastopen(sk, skb, req, &foc, dst);