commit f5a7833e83628f18c1ee94e6ffcb1d232f029be9
author Cong Wang <xiyou.wangcong@gmail.com> Tue May 26 21:35:25 2020 -0700
committer David S. Miller <davem@davemloft.net> Wed May 27 15:05:49 2020 -0700
tree 744de84947c3dab8440aecda9c93f536e3437b3b
parent a34dac0b9055202cf9c64e08d8d8dc5e23029d3a

net_sched: add a tracepoint for qdisc creation

With this tracepoint, we could know when qdisc's are created,
especially those default qdisc's.

Sample output:

  tc-736   [001] ...1    56.230107: qdisc_create: dev=ens3 kind=pfifo parent=1:0
  tc-736   [001] ...1    56.230113: qdisc_create: dev=ens3 kind=hfsc parent=ffff:ffff
  tc-738   [001] ...1    56.256816: qdisc_create: dev=ens3 kind=pfifo parent=1:100
  tc-739   [001] ...1    56.267584: qdisc_create: dev=ens3 kind=pfifo parent=1:200
  tc-740   [001] ...1    56.279649: qdisc_create: dev=ens3 kind=fq_codel parent=1:100
  tc-741   [001] ...1    56.289996: qdisc_create: dev=ens3 kind=pfifo_fast parent=1:200
  tc-745   [000] .N.1   111.687483: qdisc_create: dev=ens3 kind=ingress parent=ffff:fff1

Cc: Jamal Hadi Salim <jhs@mojatatu.com>
Cc: Jiri Pirko <jiri@resnulli.us>
Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/sched/sch_api.c

diff --git a/net/sched/sch_api.c b/net/sched/sch_api.c
index 0d99df1..9a3449b 100644
--- a/net/sched/sch_api.c
+++ b/net/sched/sch_api.c
@@ -32,6 +32,8 @@
 #include <net/pkt_sched.h>
 #include <net/pkt_cls.h>
 
+#include <trace/events/qdisc.h>
+
 /*
 
    Short review.
@@ -1283,6 +1285,7 @@ static struct Qdisc *qdisc_create(struct net_device *dev,
 	}
 
 	qdisc_hash_add(sch, false);
+	trace_qdisc_create(ops, dev, parent);
 
 	return sch;