diff mbox

[xenial] hv_netvsc: Exclude non-TCP port numbers from vRSS hashing

Message ID 1501076279-16454-2-git-send-email-marcelo.cerri@canonical.com
State New
Headers show

Commit Message

Marcelo Henrique Cerri July 26, 2017, 1:37 p.m. UTC 
From: Haiyang Zhang <haiyangz@microsoft.com>

BugLink: http://bugs.launchpad.net/bugs/1690174

Azure hosts are not supporting non-TCP port numbers in vRSS hashing for
now. For example, UDP packet loss rate will be high if port numbers are
also included in vRSS hash.

So, we created this patch to use only IP numbers for hashing in non-TCP
traffic.

Signed-off-by: Haiyang Zhang <haiyangz@microsoft.com>
Reviewed-by: Stephen Hemminger <sthemmin@microsoft.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
(backported from commit f72860afa2e32cdc674cbdd7f354f8fb62e908a6)
Signed-off-by: Marcelo Henrique Cerri <marcelo.cerri@canonical.com>

Conflicts:
	drivers/net/hyperv/netvsc_drv.c
---
 drivers/net/hyperv/netvsc_drv.c | 32 +++++++++++++++++++++++++++++++-
 1 file changed, 31 insertions(+), 1 deletion(-)

Comments

Kleber Sacilotto de Souza Aug. 7, 2017, 1:38 p.m. UTC | #1 
Applied on xenial/master-next branch.

Thank you,
Kleber
diff mbox

Patch

diff --git a/drivers/net/hyperv/netvsc_drv.c b/drivers/net/hyperv/netvsc_drv.c
index 48f1d5982bde..4b0cce6950e7 100644
--- a/drivers/net/hyperv/netvsc_drv.c
+++ b/drivers/net/hyperv/netvsc_drv.c
@@ -204,6 +204,36 @@  static void *init_ppi_data(struct rndis_message *msg, u32 ppi_size,
 	return ppi;
 }
 
+/* Azure hosts don't support non-TCP port numbers in hashing yet. We compute
+ * hash for non-TCP traffic with only IP numbers.
+ */
+static inline u32 netvsc_get_hash(struct sk_buff *skb, struct sock *sk)
+{
+	struct flow_keys flow;
+	u32 hash;
+	static u32 hashrnd __read_mostly;
+
+	net_get_random_once(&hashrnd, sizeof(hashrnd));
+
+	if (!skb_flow_dissect_flow_keys(skb, &flow, 0))
+		return 0;
+
+	if (flow.basic.ip_proto == IPPROTO_TCP) {
+		return skb_get_hash(skb);
+	} else {
+		if (flow.basic.n_proto == htons(ETH_P_IP))
+			hash = jhash2((u32 *)&flow.addrs.v4addrs, 2, hashrnd);
+		else if (flow.basic.n_proto == htons(ETH_P_IPV6))
+			hash = jhash2((u32 *)&flow.addrs.v6addrs, 8, hashrnd);
+		else
+			hash = 0;
+
+		skb_set_hash(skb, hash, PKT_HASH_TYPE_L3);
+	}
+
+	return hash;
+}
+
 static u16 netvsc_select_queue(struct net_device *ndev, struct sk_buff *skb,
 			void *accel_priv, select_queue_fallback_t fallback)
 {
@@ -215,7 +245,7 @@  static u16 netvsc_select_queue(struct net_device *ndev, struct sk_buff *skb,
 	if (nvsc_dev == NULL || ndev->real_num_tx_queues <= 1)
 		return 0;
 
-	hash = skb_get_hash(skb);
+	hash = netvsc_get_hash(skb, skb->sk);
 	q_idx = nvsc_dev->send_table[hash % VRSS_SEND_TAB_SIZE] %
 		ndev->real_num_tx_queues;