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| author | Eric Dumazet <edumazet@google.com> | 2014-10-04 10:11:31 -0700 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2014-10-06 00:55:10 -0400 |
| commit | f2600cf02b5b59aaee082c3485b7f01fc7f7b70c (patch) | |
| tree | f38d692c3f706ead3d0cfd77b216fbd629a22964 /net/sched | |
| parent | 681d2421e1135b95f5cd9d16fe10eac7f570a9f2 (diff) | |
| download | linux-f2600cf02b5b59aaee082c3485b7f01fc7f7b70c.tar.gz linux-f2600cf02b5b59aaee082c3485b7f01fc7f7b70c.tar.bz2 linux-f2600cf02b5b59aaee082c3485b7f01fc7f7b70c.zip | |
net: sched: avoid costly atomic operation in fq_dequeue()
Standard qdisc API to setup a timer implies an atomic operation on every
packet dequeue : qdisc_unthrottled()
It turns out this is not really needed for FQ, as FQ has no concept of
global qdisc throttling, being a qdisc handling many different flows,
some of them can be throttled, while others are not.
Fix is straightforward : add a 'bool throttle' to
qdisc_watchdog_schedule_ns(), and remove calls to qdisc_unthrottled()
in sch_fq.
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/sched')
| -rw-r--r-- | net/sched/sch_api.c | 5 | ||||
| -rw-r--r-- | net/sched/sch_fq.c | 6 | ||||
| -rw-r--r-- | net/sched/sch_tbf.c | 3 |
3 files changed, 7 insertions, 7 deletions
diff --git a/net/sched/sch_api.c b/net/sched/sch_api.c index c79a226cc25c..2cf61b3e633c 100644 --- a/net/sched/sch_api.c +++ b/net/sched/sch_api.c @@ -594,13 +594,14 @@ 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_ns(struct qdisc_watchdog *wd, u64 expires, bool throttle) { if (test_bit(__QDISC_STATE_DEACTIVATED, &qdisc_root_sleeping(wd->qdisc)->state)) return; - qdisc_throttled(wd->qdisc); + if (throttle) + qdisc_throttled(wd->qdisc); hrtimer_start(&wd->timer, ns_to_ktime(expires), diff --git a/net/sched/sch_fq.c b/net/sched/sch_fq.c index c9b9fcb53206..cbd7e1fd23b4 100644 --- a/net/sched/sch_fq.c +++ b/net/sched/sch_fq.c @@ -377,7 +377,6 @@ static int fq_enqueue(struct sk_buff *skb, struct Qdisc *sch) if (time_after(jiffies, f->age + q->flow_refill_delay)) f->credit = max_t(u32, f->credit, q->quantum); q->inactive_flows--; - qdisc_unthrottled(sch); } /* Note: this overwrites f->age */ @@ -385,7 +384,6 @@ static int fq_enqueue(struct sk_buff *skb, struct Qdisc *sch) if (unlikely(f == &q->internal)) { q->stat_internal_packets++; - qdisc_unthrottled(sch); } sch->q.qlen++; @@ -433,7 +431,8 @@ begin: if (!head->first) { if (q->time_next_delayed_flow != ~0ULL) qdisc_watchdog_schedule_ns(&q->watchdog, - q->time_next_delayed_flow); + q->time_next_delayed_flow, + false); return NULL; } } @@ -495,7 +494,6 @@ begin: } out: qdisc_bstats_update(sch, skb); - qdisc_unthrottled(sch); return skb; } diff --git a/net/sched/sch_tbf.c b/net/sched/sch_tbf.c index 77edffe329c4..a4afde14e865 100644 --- a/net/sched/sch_tbf.c +++ b/net/sched/sch_tbf.c @@ -268,7 +268,8 @@ static struct sk_buff *tbf_dequeue(struct Qdisc *sch) } qdisc_watchdog_schedule_ns(&q->watchdog, - now + max_t(long, -toks, -ptoks)); + now + max_t(long, -toks, -ptoks), + true); /* Maybe we have a shorter packet in the queue, which can be sent now. It sounds cool, |