net_sched: sch_htb: export class backlog in dumps

We already get child qdisc qlen, we also can get its backlog
so that class dumps can report it.

Also replace qstats by a single drop counter, but move it in
a separate cache line so that drops do not dirty useful cache lines.

Tested:

$ tc -s cl sh dev eth0
class htb 1:1 root leaf 3: prio 0 rate 1Gbit ceil 1Gbit burst 500000b cburst 500000b
 Sent 2183346912 bytes 9021815 pkt (dropped 2340774, overlimits 0 requeues 0)
 rate 1001Mbit 517543pps backlog 120758b 499p requeues 0
 lended: 9021770 borrowed: 0 giants: 0
 tokens: 9 ctokens: 9

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

diff --git a/net/sched/sch_htb.c b/net/sched/sch_htb.c
index f388225..ba098f2 100644 (file)
--- a/net/sched/sch_htb.c
+++ b/net/sched/sch_htb.c
@@ -117,7 +117,6 @@ struct htb_class {
         * Written often fields
         */
        struct gnet_stats_basic_packed bstats;
-       struct gnet_stats_queue qstats;
        struct tc_htb_xstats    xstats; /* our special stats */
 
        /* token bucket parameters */
@@ -140,6 +139,8 @@ struct htb_class {
        enum htb_cmode          cmode;          /* current mode of the class */
        struct rb_node          pq_node;        /* node for event queue */
        struct rb_node          node[TC_HTB_NUMPRIO];   /* node for self or feed tree */
+
+       unsigned int drops ____cacheline_aligned_in_smp;
 };
 
 struct htb_level {
@@ -595,7 +596,7 @@ static int htb_enqueue(struct sk_buff *skb, struct Qdisc *sch,
                                        to_free)) != NET_XMIT_SUCCESS) {
                if (net_xmit_drop_count(ret)) {
                        qdisc_qstats_drop(sch);
-                       cl->qstats.drops++;
+                       cl->drops++;
                }
                return ret;
        } else {
@@ -1110,17 +1111,22 @@ static int
 htb_dump_class_stats(struct Qdisc *sch, unsigned long arg, struct gnet_dump *d)
 {
        struct htb_class *cl = (struct htb_class *)arg;
+       struct gnet_stats_queue qs = {
+               .drops = cl->drops,
+       };
        __u32 qlen = 0;
 
-       if (!cl->level && cl->un.leaf.q)
+       if (!cl->level && cl->un.leaf.q) {
                qlen = cl->un.leaf.q->q.qlen;
+               qs.backlog = cl->un.leaf.q->qstats.backlog;
+       }
        cl->xstats.tokens = PSCHED_NS2TICKS(cl->tokens);
        cl->xstats.ctokens = PSCHED_NS2TICKS(cl->ctokens);
 
        if (gnet_stats_copy_basic(qdisc_root_sleeping_running(sch),
                                  d, NULL, &cl->bstats) < 0 ||
            gnet_stats_copy_rate_est(d, NULL, &cl->rate_est) < 0 ||
-           gnet_stats_copy_queue(d, NULL, &cl->qstats, qlen) < 0)
+           gnet_stats_copy_queue(d, NULL, &qs, qlen) < 0)
                return -1;
 
        return gnet_stats_copy_app(d, &cl->xstats, sizeof(cl->xstats));