datapath: Use percpu allocator for flow-stats.

Use percpu allocator for stats due to objection to stats array.
But percpu allocator is not designed for high churn allocation/
deallcation. so we need to avoid allocating percpu flow for
short lived flows. One cheaper way to detect flow is by checking
if 5-tuple used in RSS are masked or not. if any one of them is
masked, flow is likely shared across CPU where percpu stat
should be more scalable. And that flow should be relatively
long lived flow.

Signed-off-by: Pravin B Shelar <pshelar@nicira.com>
Acked-by: Jesse Gross <jesse@nicira.com>

1 files changed, 52 insertions, 4 deletions

diff --git a/datapath/flow_netlink.c b/datapath/flow_netlink.c
index 75c72b361..9b26528b0 100644
--- a/datapath/flow_netlink.c
+++ b/datapath/flow_netlink.c
@@ -266,6 +266,20 @@ static bool is_all_zero(const u8 *fp, size_t size)
 	return true;
 }
 
+static bool is_all_set(const u8 *fp, size_t size)
+{
+	int i;
+
+	if (!fp)
+		return false;
+
+	for (i = 0; i < size; i++)
+		if (fp[i] != 0xff)
+			return false;
+
+	return true;
+}
+
 static int __parse_flow_nlattrs(const struct nlattr *attr,
 				const struct nlattr *a[],
 				u64 *attrsp, bool nz)
@@ -487,8 +501,9 @@ static int metadata_from_nlattrs(struct sw_flow_match *match,  u64 *attrs,
 	return 0;
 }
 
-static int ovs_key_from_nlattrs(struct sw_flow_match *match,  u64 attrs,
-				const struct nlattr **a, bool is_mask)
+static int ovs_key_from_nlattrs(struct sw_flow_match *match,  bool *exact_5tuple,
+				u64 attrs, const struct nlattr **a,
+				bool is_mask)
 {
 	int err;
 	u64 orig_attrs = attrs;
@@ -545,6 +560,11 @@ static int ovs_key_from_nlattrs(struct sw_flow_match *match,  u64 attrs,
 		SW_FLOW_KEY_PUT(match, eth.type, htons(ETH_P_802_2), is_mask);
 	}
 
+	if (is_mask && exact_5tuple) {
+		if (match->mask->key.eth.type != htons(0xffff))
+			*exact_5tuple = false;
+	}
+
 	if (attrs & (1ULL << OVS_KEY_ATTR_IPV4)) {
 		const struct ovs_key_ipv4 *ipv4_key;
 
@@ -567,6 +587,13 @@ static int ovs_key_from_nlattrs(struct sw_flow_match *match,  u64 attrs,
 		SW_FLOW_KEY_PUT(match, ipv4.addr.dst,
 				ipv4_key->ipv4_dst, is_mask);
 		attrs &= ~(1ULL << OVS_KEY_ATTR_IPV4);
+
+		if (is_mask && exact_5tuple && *exact_5tuple) {
+			if (ipv4_key->ipv4_proto != 0xff ||
+			    ipv4_key->ipv4_src != htonl(0xffffffff) ||
+			    ipv4_key->ipv4_dst != htonl(0xffffffff))
+				*exact_5tuple = false;
+		}
 	}
 
 	if (attrs & (1ULL << OVS_KEY_ATTR_IPV6)) {
@@ -598,6 +625,13 @@ static int ovs_key_from_nlattrs(struct sw_flow_match *match,  u64 attrs,
 				is_mask);
 
 		attrs &= ~(1ULL << OVS_KEY_ATTR_IPV6);
+
+		if (is_mask && exact_5tuple && *exact_5tuple) {
+			if (ipv6_key->ipv6_proto != 0xff ||
+			    !is_all_set((u8 *)ipv6_key->ipv6_src, sizeof(match->key->ipv6.addr.src)) ||
+			    !is_all_set((u8 *)ipv6_key->ipv6_dst, sizeof(match->key->ipv6.addr.dst)))
+				*exact_5tuple = false;
+		}
 	}
 
 	if (attrs & (1ULL << OVS_KEY_ATTR_ARP)) {
@@ -640,6 +674,11 @@ static int ovs_key_from_nlattrs(struct sw_flow_match *match,  u64 attrs,
 					tcp_key->tcp_dst, is_mask);
 		}
 		attrs &= ~(1ULL << OVS_KEY_ATTR_TCP);
+
+		if (is_mask && exact_5tuple && *exact_5tuple &&
+		    (tcp_key->tcp_src != htons(0xffff) ||
+		     tcp_key->tcp_dst != htons(0xffff)))
+			*exact_5tuple = false;
 	}
 
 	if (attrs & (1ULL << OVS_KEY_ATTR_TCP_FLAGS)) {
@@ -671,6 +710,11 @@ static int ovs_key_from_nlattrs(struct sw_flow_match *match,  u64 attrs,
 					udp_key->udp_dst, is_mask);
 		}
 		attrs &= ~(1ULL << OVS_KEY_ATTR_UDP);
+
+		if (is_mask && exact_5tuple && *exact_5tuple &&
+		    (udp_key->udp_src != htons(0xffff) ||
+		     udp_key->udp_dst != htons(0xffff)))
+			*exact_5tuple = false;
 	}
 
 	if (attrs & (1ULL << OVS_KEY_ATTR_SCTP)) {
@@ -756,6 +800,7 @@ static void sw_flow_mask_set(struct sw_flow_mask *mask,
  * attribute specifies the mask field of the wildcarded flow.
  */
 int ovs_nla_get_match(struct sw_flow_match *match,
+		      bool *exact_5tuple,
 		      const struct nlattr *key,
 		      const struct nlattr *mask)
 {
@@ -803,10 +848,13 @@ int ovs_nla_get_match(struct sw_flow_match *match,
 		}
 	}
 
-	err = ovs_key_from_nlattrs(match, key_attrs, a, false);
+	err = ovs_key_from_nlattrs(match, NULL, key_attrs, a, false);
 	if (err)
 		return err;
 
+	if (exact_5tuple)
+		*exact_5tuple = true;
+
 	if (mask) {
 		err = parse_flow_mask_nlattrs(mask, a, &mask_attrs);
 		if (err)
@@ -844,7 +892,7 @@ int ovs_nla_get_match(struct sw_flow_match *match,
 			}
 		}
 
-		err = ovs_key_from_nlattrs(match, mask_attrs, a, true);
+		err = ovs_key_from_nlattrs(match, exact_5tuple, mask_attrs, a, true);
 		if (err)
 			return err;
 	} else {