From 32f7b44d0f5661044fcfa84e9ad402ed9d759107 Mon Sep 17 00:00:00 2001 From: Paolo Abeni Date: Tue, 15 May 2018 10:50:31 +0200 Subject: sched: manipulate __QDISC_STATE_RUNNING in qdisc_run_* helpers Currently NOLOCK qdiscs pay a measurable overhead to atomically manipulate the __QDISC_STATE_RUNNING. Such bit is flipped twice per packet in the uncontended scenario with packet rate below the line rate: on packed dequeue and on the next, failing dequeue attempt. This changeset moves the bit manipulation into the qdisc_run_{begin,end} helpers, so that the bit is now flipped only once per packet, with measurable performance improvement in the uncontended scenario. This also allows simplifying the qdisc teardown code path - since qdisc_is_running() is now effective for each qdisc type - and avoid a possible race between qdisc_run() and dev_deactivate_many(), as now the some_qdisc_is_busy() can properly detect NOLOCK qdiscs being busy dequeuing packets. Signed-off-by: Paolo Abeni Signed-off-by: David S. Miller --- net/core/dev.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'net/core/dev.c') diff --git a/net/core/dev.c b/net/core/dev.c index 9f4390182384..7ca19f47a92a 100644 --- a/net/core/dev.c +++ b/net/core/dev.c @@ -3244,7 +3244,7 @@ static inline int __dev_xmit_skb(struct sk_buff *skb, struct Qdisc *q, rc = NET_XMIT_DROP; } else { rc = q->enqueue(skb, q, &to_free) & NET_XMIT_MASK; - __qdisc_run(q); + qdisc_run(q); } if (unlikely(to_free)) -- cgit v1.2.3