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>

13 files changed, 54 insertions, 30 deletions

diff --git a/include/net/act_api.h b/include/net/act_api.h
index 06ef7e926a66..b8ffac7b6bab 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 a79b6cfb02a8..cf8439ba4d11 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 5a2978d1cb22..495c71f66e7e 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 e7f4e21cc3e1..df5676029827 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 552c8a0a12d1..6487317ea619 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
diff --git a/net/core/gen_estimator.c b/net/core/gen_estimator.c
index d9d198aa9fed..6b5b6e7013ca 100644
--- a/net/core/gen_estimator.c
+++ b/net/core/gen_estimator.c
@@ -82,7 +82,7 @@ struct gen_estimator
 {
         struct list_head        list;
         struct gnet_stats_basic_packed  *bstats;
-        struct gnet_stats_rate_est      *rate_est;
+        struct gnet_stats_rate_est64    *rate_est;
         spinlock_t              *stats_lock;
         int                     ewma_log;
         u64                     last_bytes;
@@ -167,7 +167,7 @@ static void gen_add_node(struct gen_estimator *est)
 
 static
 struct gen_estimator *gen_find_node(const struct gnet_stats_basic_packed *bstats,
-                                    const struct gnet_stats_rate_est *rate_est)
+                                    const struct gnet_stats_rate_est64 *rate_est)
 {
         struct rb_node *p = est_root.rb_node;
 
@@ -203,7 +203,7 @@ struct gen_estimator *gen_find_node(const struct gnet_stats_basic_packed *bstats
  *
  */
 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)
 {
@@ -258,7 +258,7 @@ EXPORT_SYMBOL(gen_new_estimator);
  * Note : Caller should respect an RCU grace period before freeing stats_lock
  */
 void gen_kill_estimator(struct gnet_stats_basic_packed *bstats,
-                        struct gnet_stats_rate_est *rate_est)
+                        struct gnet_stats_rate_est64 *rate_est)
 {
         struct gen_estimator *e;
 
@@ -290,7 +290,7 @@ EXPORT_SYMBOL(gen_kill_estimator);
  * Returns 0 on success or a negative error code.
  */
 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)
 {
         gen_kill_estimator(bstats, rate_est);
@@ -306,7 +306,7 @@ EXPORT_SYMBOL(gen_replace_estimator);
  * Returns true if estimator is active, and false if not.
  */
 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)
 {
         bool res;
 
diff --git a/net/core/gen_stats.c b/net/core/gen_stats.c
index ddedf211e588..9d3d9e78397b 100644
--- a/net/core/gen_stats.c
+++ b/net/core/gen_stats.c
@@ -143,18 +143,30 @@ EXPORT_SYMBOL(gnet_stats_copy_basic);
 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)
 {
+        struct gnet_stats_rate_est est;
+        int res;
+
         if (b && !gen_estimator_active(b, r))
                 return 0;
 
+        est.bps = min_t(u64, UINT_MAX, r->bps);
+        /* we have some time before reaching 2^32 packets per second */
+        est.pps = r->pps;
+
         if (d->compat_tc_stats) {
-                d->tc_stats.bps = r->bps;
-                d->tc_stats.pps = r->pps;
+                d->tc_stats.bps = est.bps;
+                d->tc_stats.pps = est.pps;
         }
 
-        if (d->tail)
-                return gnet_stats_copy(d, TCA_STATS_RATE_EST, r, sizeof(*r));
+        if (d->tail) {
+                res = gnet_stats_copy(d, TCA_STATS_RATE_EST, &est, sizeof(est));
+                if (res < 0 || est.bps == r->bps)
+                        return res;
+                /* emit 64bit stats only if needed */
+                return gnet_stats_copy(d, TCA_STATS_RATE_EST64, r, sizeof(*r));
+        }
 
         return 0;
 }
diff --git a/net/netfilter/xt_rateest.c b/net/netfilter/xt_rateest.c
index ed0db15ab00e..7720b036d76a 100644
--- a/net/netfilter/xt_rateest.c
+++ b/net/netfilter/xt_rateest.c
@@ -18,7 +18,7 @@ static bool
 xt_rateest_mt(const struct sk_buff *skb, struct xt_action_param *par)
 {
         const struct xt_rateest_match_info *info = par->matchinfo;
-        struct gnet_stats_rate_est *r;
+        struct gnet_stats_rate_est64 *r;
         u_int32_t bps1, bps2, pps1, pps2;
         bool ret = true;
 
diff --git a/net/sched/sch_cbq.c b/net/sched/sch_cbq.c
index 1bc210ffcba2..71a568862557 100644
--- a/net/sched/sch_cbq.c
+++ b/net/sched/sch_cbq.c
@@ -130,7 +130,7 @@ struct cbq_class {
         psched_time_t           penalized;
         struct gnet_stats_basic_packed bstats;
         struct gnet_stats_queue qstats;
-        struct gnet_stats_rate_est rate_est;
+        struct gnet_stats_rate_est64 rate_est;
         struct tc_cbq_xstats    xstats;
 
         struct tcf_proto        *filter_list;
diff --git a/net/sched/sch_drr.c b/net/sched/sch_drr.c
index 759b308d1a8d..8302717ea303 100644
--- a/net/sched/sch_drr.c
+++ b/net/sched/sch_drr.c
@@ -25,7 +25,7 @@ struct drr_class {
 
         struct gnet_stats_basic_packed          bstats;
         struct gnet_stats_queue         qstats;
-        struct gnet_stats_rate_est      rate_est;
+        struct gnet_stats_rate_est64    rate_est;
         struct list_head                alist;
         struct Qdisc                    *qdisc;
 
diff --git a/net/sched/sch_hfsc.c b/net/sched/sch_hfsc.c
index 9facea03faeb..c4075610502c 100644
--- a/net/sched/sch_hfsc.c
+++ b/net/sched/sch_hfsc.c
@@ -114,7 +114,7 @@ struct hfsc_class {
 
         struct gnet_stats_basic_packed bstats;
         struct gnet_stats_queue qstats;
-        struct gnet_stats_rate_est rate_est;
+        struct gnet_stats_rate_est64 rate_est;
         unsigned int    level;          /* class level in hierarchy */
         struct tcf_proto *filter_list;  /* filter list */
         unsigned int    filter_cnt;     /* filter count */
diff --git a/net/sched/sch_htb.c b/net/sched/sch_htb.c
index adaedd79389c..162fb800754c 100644
--- a/net/sched/sch_htb.c
+++ b/net/sched/sch_htb.c
@@ -78,7 +78,7 @@ struct htb_class {
         /* general class parameters */
         struct gnet_stats_basic_packed bstats;
         struct gnet_stats_queue qstats;
-        struct gnet_stats_rate_est rate_est;
+        struct gnet_stats_rate_est64 rate_est;
         struct tc_htb_xstats xstats;    /* our special stats */
         int refcnt;             /* usage count of this class */
 
diff --git a/net/sched/sch_qfq.c b/net/sched/sch_qfq.c
index d51852bba01c..7c195d972bf0 100644
--- a/net/sched/sch_qfq.c
+++ b/net/sched/sch_qfq.c
@@ -138,7 +138,7 @@ struct qfq_class {
 
         struct gnet_stats_basic_packed bstats;
         struct gnet_stats_queue qstats;
-        struct gnet_stats_rate_est rate_est;
+        struct gnet_stats_rate_est64 rate_est;
         struct Qdisc *qdisc;
         struct list_head alist;         /* Link for active-classes list. */
         struct qfq_aggregate *agg;      /* Parent aggregate. */