net_sched: add 64bit rate estimators

struct gnet_stats_rate_est contains u32 fields, so the bytes per second
field can wrap at 34360Mbit.

Add a new gnet_stats_rate_est64 structure to get 64bit bps/pps fields,
and switch the kernel to use this structure natively.

This structure is dumped to user space as a new attribute :

TCA_STATS_RATE_EST64

Old tc command will now display the capped bps (to 34360Mbit), instead
of wrapped values, and updated tc command will display correct
information.

Old tc command output, after patch :

eric:~# tc -s -d qd sh dev lo
qdisc pfifo 8001: root refcnt 2 limit 1000p
 Sent 80868245400 bytes 1978837 pkt (dropped 0, overlimits 0 requeues 0)
 rate 34360Mbit 189696pps backlog 0b 0p requeues 0

This patch carefully reorganizes "struct Qdisc" layout to get optimal
performance on SMP.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Ben Hutchings <bhutchings@solarflare.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

5 files changed, 25 insertions, 13 deletions

diff --git a/include/net/act_api.h b/include/net/act_api.h
index 06ef7e926a6..b8ffac7b6ba 100644
--- a/include/net/act_api.h
+++ b/include/net/act_api.h
@@ -18,7 +18,7 @@ struct tcf_common {
 	struct tcf_t			tcfc_tm;
 	struct gnet_stats_basic_packed	tcfc_bstats;
 	struct gnet_stats_queue		tcfc_qstats;
-	struct gnet_stats_rate_est	tcfc_rate_est;
+	struct gnet_stats_rate_est64	tcfc_rate_est;
 	spinlock_t			tcfc_lock;
 	struct rcu_head			tcfc_rcu;
 };
diff --git a/include/net/gen_stats.h b/include/net/gen_stats.h
index a79b6cfb02a..cf8439ba4d1 100644
--- a/include/net/gen_stats.h
+++ b/include/net/gen_stats.h
@@ -30,7 +30,7 @@ extern int gnet_stats_copy_basic(struct gnet_dump *d,
 				 struct gnet_stats_basic_packed *b);
 extern int gnet_stats_copy_rate_est(struct gnet_dump *d,
 				    const struct gnet_stats_basic_packed *b,
-				    struct gnet_stats_rate_est *r);
+				    struct gnet_stats_rate_est64 *r);
 extern int gnet_stats_copy_queue(struct gnet_dump *d,
 				 struct gnet_stats_queue *q);
 extern int gnet_stats_copy_app(struct gnet_dump *d, void *st, int len);
@@ -38,13 +38,13 @@ extern int gnet_stats_copy_app(struct gnet_dump *d, void *st, int len);
 extern int gnet_stats_finish_copy(struct gnet_dump *d);
 
 extern int gen_new_estimator(struct gnet_stats_basic_packed *bstats,
-			     struct gnet_stats_rate_est *rate_est,
+			     struct gnet_stats_rate_est64 *rate_est,
 			     spinlock_t *stats_lock, struct nlattr *opt);
 extern void gen_kill_estimator(struct gnet_stats_basic_packed *bstats,
-			       struct gnet_stats_rate_est *rate_est);
+			       struct gnet_stats_rate_est64 *rate_est);
 extern int gen_replace_estimator(struct gnet_stats_basic_packed *bstats,
-				 struct gnet_stats_rate_est *rate_est,
+				 struct gnet_stats_rate_est64 *rate_est,
 				 spinlock_t *stats_lock, struct nlattr *opt);
 extern bool gen_estimator_active(const struct gnet_stats_basic_packed *bstats,
-				 const struct gnet_stats_rate_est *rate_est);
+				 const struct gnet_stats_rate_est64 *rate_est);
 #endif
diff --git a/include/net/netfilter/xt_rateest.h b/include/net/netfilter/xt_rateest.h
index 5a2978d1cb2..495c71f66e7 100644
--- a/include/net/netfilter/xt_rateest.h
+++ b/include/net/netfilter/xt_rateest.h
@@ -6,7 +6,7 @@ struct xt_rateest {
 	struct gnet_stats_basic_packed	bstats;
 	spinlock_t			lock;
 	/* keep rstats and lock on same cache line to speedup xt_rateest_mt() */
-	struct gnet_stats_rate_est	rstats;
+	struct gnet_stats_rate_est64	rstats;
 
 	/* following fields not accessed in hot path */
 	struct hlist_node		list;
diff --git a/include/net/sch_generic.h b/include/net/sch_generic.h
index e7f4e21cc3e..df567602982 100644
--- a/include/net/sch_generic.h
+++ b/include/net/sch_generic.h
@@ -58,14 +58,12 @@ struct Qdisc {
 				      * multiqueue device.
 				      */
 #define TCQ_F_WARN_NONWC	(1 << 16)
-	int			padded;
+	u32			limit;
 	const struct Qdisc_ops	*ops;
 	struct qdisc_size_table	__rcu *stab;
 	struct list_head	list;
 	u32			handle;
 	u32			parent;
-	atomic_t		refcnt;
-	struct gnet_stats_rate_est	rate_est;
 	int			(*reshape_fail)(struct sk_buff *skb,
 					struct Qdisc *q);
 
@@ -76,8 +74,9 @@ struct Qdisc {
 	 */
 	struct Qdisc		*__parent;
 	struct netdev_queue	*dev_queue;
-	struct Qdisc		*next_sched;
 
+	struct gnet_stats_rate_est64	rate_est;
+	struct Qdisc		*next_sched;
 	struct sk_buff		*gso_skb;
 	/*
 	 * For performance sake on SMP, we put highly modified fields at the end
@@ -88,8 +87,10 @@ struct Qdisc {
 	unsigned int		__state;
 	struct gnet_stats_queue	qstats;
 	struct rcu_head		rcu_head;
-	spinlock_t		busylock;
-	u32			limit;
+	int			padded;
+	atomic_t		refcnt;
+
+	spinlock_t		busylock ____cacheline_aligned_in_smp;
 };
 
 static inline bool qdisc_is_running(const struct Qdisc *qdisc)
diff --git a/include/uapi/linux/gen_stats.h b/include/uapi/linux/gen_stats.h
index 552c8a0a12d..6487317ea61 100644
--- a/include/uapi/linux/gen_stats.h
+++ b/include/uapi/linux/gen_stats.h
@@ -9,6 +9,7 @@ enum {
 	TCA_STATS_RATE_EST,
 	TCA_STATS_QUEUE,
 	TCA_STATS_APP,
+	TCA_STATS_RATE_EST64,
 	__TCA_STATS_MAX,
 };
 #define TCA_STATS_MAX (__TCA_STATS_MAX - 1)
@@ -38,6 +39,16 @@ struct gnet_stats_rate_est {
 };
 
 /**
+ * struct gnet_stats_rate_est64 - rate estimator
+ * @bps: current byte rate
+ * @pps: current packet rate
+ */
+struct gnet_stats_rate_est64 {
+	__u64	bps;
+	__u64	pps;
+};
+
+/**
  * struct gnet_stats_queue - queuing statistics
  * @qlen: queue length
  * @backlog: backlog size of queue