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| author |   Eric Dumazet <eric.dumazet@gmail.com> | 2011-01-20 03:48:19 +0000 |
|---|---|---|
| committer |   David S. Miller <davem@davemloft.net> | 2011-01-20 16:59:32 -0800 |
| commit | a2da570d62fcb9e8816f6920e1ec02c706b289fa (patch) | |
| tree | 9a24b76262c40ec2f1be11e29e224c7d7b20fa26 /net/core/dev.c | |
| parent | net_sched: move TCQ_F_THROTTLED flag (diff) | |
| download | linux-dev-a2da570d62fcb9e8816f6920e1ec02c706b289fa.tar.xz linux-dev-a2da570d62fcb9e8816f6920e1ec02c706b289fa.zip | |
net_sched: RCU conversion of stab
This patch converts stab qdisc management to RCU, so that we can perform
the qdisc_calculate_pkt_len() call before getting qdisc lock.
This shortens the lock's held time in __dev_xmit_skb().
This permits more qdiscs to get TCQ_F_CAN_BYPASS status, avoiding lot of
cache misses and so reducing latencies.
Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
CC: Patrick McHardy <kaber@trash.net>
CC: Jesper Dangaard Brouer <hawk@diku.dk>
CC: Jarek Poplawski <jarkao2@gmail.com>
CC: Jamal Hadi Salim <hadi@cyberus.ca>
CC: Stephen Hemminger <shemminger@vyatta.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/core/dev.c')
| -rw-r--r-- | net/core/dev.c | 8 |
1 files changed, 5 insertions, 3 deletions
diff --git a/net/core/dev.c b/net/core/dev.c index a4ccd47f3196..2730352d2ccc 100644 --- a/net/core/dev.c +++ b/net/core/dev.c @@ -2325,15 +2325,18 @@ static inline int __dev_xmit_skb(struct sk_buff *skb, struct Qdisc *q, struct netdev_queue *txq) { spinlock_t *root_lock = qdisc_lock(q); - bool contended = qdisc_is_running(q); + bool contended; int rc; + qdisc_skb_cb(skb)->pkt_len = skb->len; + qdisc_calculate_pkt_len(skb, q); /* * Heuristic to force contended enqueues to serialize on a * separate lock before trying to get qdisc main lock. * This permits __QDISC_STATE_RUNNING owner to get the lock more often * and dequeue packets faster. */ + contended = qdisc_is_running(q); if (unlikely(contended)) spin_lock(&q->busylock); @@ -2351,7 +2354,6 @@ static inline int __dev_xmit_skb(struct sk_buff *skb, struct Qdisc *q, if (!(dev->priv_flags & IFF_XMIT_DST_RELEASE)) skb_dst_force(skb); - qdisc_skb_cb(skb)->pkt_len = skb->len; qdisc_bstats_update(q, skb); if (sch_direct_xmit(skb, q, dev, txq, root_lock)) { @@ -2366,7 +2368,7 @@ static inline int __dev_xmit_skb(struct sk_buff *skb, struct Qdisc *q, rc = NET_XMIT_SUCCESS; } else { skb_dst_force(skb); - rc = qdisc_enqueue_root(skb, q); + rc = q->enqueue(skb, q) & NET_XMIT_MASK; if (qdisc_run_begin(q)) { if (unlikely(contended)) { spin_unlock(&q->busylock); |