[PATCH net-next 1/3] net_sched: add qdisc_watchdog_schedule_range_ns()

[Eric Dumazet <edumazet@google.com>]

Some packet schedulers might want to add a slack
when programming hrtimers. This can reduce number
of interrupts and increase batch sizes and thus
give good xmit_more savings.

This commit adds qdisc_watchdog_schedule_range_ns()
helper, with an extra delta_ns parameter.

Legacy qdisc_watchdog_schedule_n() becomes an inline
passing a zero slack.

Signed-off-by: Eric Dumazet <edumazet@google.com>
---
 include/net/pkt_sched.h | 10 +++++++++-
 net/sched/sch_api.c     | 12 +++++++-----
 2 files changed, 16 insertions(+), 6 deletions(-)

diff --git a/include/net/pkt_sched.h b/include/net/pkt_sched.h
index 20d2c6419612fd4d35b0960456394ea69ced7e7d..9092e697059e775af307be69a879386ebfd9924f 100644
--- a/include/net/pkt_sched.h
+++ b/include/net/pkt_sched.h
@@ -75,7 +75,15 @@ struct qdisc_watchdog {
 void qdisc_watchdog_init_clockid(struct qdisc_watchdog *wd, struct Qdisc *qdisc,
 				 clockid_t clockid);
 void qdisc_watchdog_init(struct qdisc_watchdog *wd, struct Qdisc *qdisc);
-void qdisc_watchdog_schedule_ns(struct qdisc_watchdog *wd, u64 expires);
+
+void qdisc_watchdog_schedule_range_ns(struct qdisc_watchdog *wd, u64 expires,
+				      u64 delta_ns);
+
+static inline void qdisc_watchdog_schedule_ns(struct qdisc_watchdog *wd,
+					      u64 expires)
+{
+	return qdisc_watchdog_schedule_range_ns(wd, expires, 0ULL);
+}
 
 static inline void qdisc_watchdog_schedule(struct qdisc_watchdog *wd,
 					   psched_time_t expires)
diff --git a/net/sched/sch_api.c b/net/sched/sch_api.c
index 50794125bf0240031c142045d09b429cf945029f..83984be04f57d93b4efc50bb9cf390b116101fdd 100644
--- a/net/sched/sch_api.c
+++ b/net/sched/sch_api.c
@@ -618,7 +618,8 @@ void qdisc_watchdog_init(struct qdisc_watchdog *wd, struct Qdisc *qdisc)
 }
 EXPORT_SYMBOL(qdisc_watchdog_init);
 
-void qdisc_watchdog_schedule_ns(struct qdisc_watchdog *wd, u64 expires)
+void qdisc_watchdog_schedule_range_ns(struct qdisc_watchdog *wd, u64 expires,
+				      u64 delta_ns)
 {
 	if (test_bit(__QDISC_STATE_DEACTIVATED,
 		     &qdisc_root_sleeping(wd->qdisc)->state))
@@ -628,11 +629,12 @@ void qdisc_watchdog_schedule_ns(struct qdisc_watchdog *wd, u64 expires)
 		return;
 
 	wd->last_expires = expires;
-	hrtimer_start(&wd->timer,
-		      ns_to_ktime(expires),
-		      HRTIMER_MODE_ABS_PINNED);
+	hrtimer_start_range_ns(&wd->timer,
+			       ns_to_ktime(expires),
+			       delta_ns,
+			       HRTIMER_MODE_ABS_PINNED);
 }
-EXPORT_SYMBOL(qdisc_watchdog_schedule_ns);
+EXPORT_SYMBOL(qdisc_watchdog_schedule_range_ns);
 
 void qdisc_watchdog_cancel(struct qdisc_watchdog *wd)
 {
-- 
2.25.1.481.gfbce0eb801-goog