diff options
| author | Paolo Abeni <pabeni@redhat.com> | 2018-05-15 11:50:31 +0300 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2018-05-16 19:26:25 +0300 |
| commit | 32f7b44d0f5661044fcfa84e9ad402ed9d759107 (patch) | |
| tree | d2453e21a4187e32c9da74a25bbfee4446e725b5 /net/core/dev.c | |
| parent | 5a63f77af7d69deb02a92b60d61141fe687997f8 (diff) | |
| download | linux-32f7b44d0f5661044fcfa84e9ad402ed9d759107.tar.xz | |
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 <pabeni@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/core/dev.c')
| -rw-r--r-- | net/core/dev.c | 2 |
1 files changed, 1 insertions, 1 deletions
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)) |