openvswitch: Per cpu flow stats.

With mega flow implementation ovs flow can be shared between
multiple CPUs which makes stats updates highly contended
operation. This patch uses per-CPU stats in cases where a flow
is likely to be shared (if there is a wildcard in the 5-tuple
and therefore likely to be spread by RSS). In other situations,
it uses the current strategy, saving memory and allocation time.

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

1 files changed, 22 insertions, 7 deletions

diff --git a/net/openvswitch/flow.h b/net/openvswitch/flow.h
index 176406d9b779..2d770e28a3a3 100644
--- a/net/openvswitch/flow.h
+++ b/net/openvswitch/flow.h
@@ -19,6 +19,7 @@
 #ifndef FLOW_H
 #define FLOW_H 1
 
+#include <linux/cache.h>
 #include <linux/kernel.h>
 #include <linux/netlink.h>
 #include <linux/openvswitch.h>
@@ -146,6 +147,22 @@ struct sw_flow_actions {
         struct nlattr actions[];
 };
 
+struct flow_stats {
+        u64 packet_count;               /* Number of packets matched. */
+        u64 byte_count;                 /* Number of bytes matched. */
+        unsigned long used;             /* Last used time (in jiffies). */
+        spinlock_t lock;                /* Lock for atomic stats update. */
+        __be16 tcp_flags;               /* Union of seen TCP flags. */
+};
+
+struct sw_flow_stats {
+        bool is_percpu;
+        union {
+                struct flow_stats *stat;
+                struct flow_stats __percpu *cpu_stats;
+        };
+};
+
 struct sw_flow {
         struct rcu_head rcu;
         struct hlist_node hash_node[2];
@@ -155,12 +172,7 @@ struct sw_flow {
         struct sw_flow_key unmasked_key;
         struct sw_flow_mask *mask;
         struct sw_flow_actions __rcu *sf_acts;
-
-        spinlock_t lock;        /* Lock for values below. */
-        unsigned long used;     /* Last used time (in jiffies). */
-        u64 packet_count;       /* Number of packets matched. */
-        u64 byte_count;         /* Number of bytes matched. */
-        __be16 tcp_flags;       /* Union of seen TCP flags. */
+        struct sw_flow_stats stats;
 };
 
 struct arp_eth_header {
@@ -177,7 +189,10 @@ struct arp_eth_header {
         unsigned char       ar_tip[4];          /* target IP address        */
 } __packed;
 
-void ovs_flow_used(struct sw_flow *, struct sk_buff *);
+void ovs_flow_stats_update(struct sw_flow *flow, struct sk_buff *skb);
+void ovs_flow_stats_get(struct sw_flow *flow, struct ovs_flow_stats *stats,
+                        unsigned long *used, __be16 *tcp_flags);
+void ovs_flow_stats_clear(struct sw_flow *flow);
 u64 ovs_flow_used_time(unsigned long flow_jiffies);
 
 int ovs_flow_extract(struct sk_buff *, u16 in_port, struct sw_flow_key *);