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| author | Yunsheng Lin <linyunsheng@huawei.com> | 2021-05-14 11:17:01 +0800 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2021-05-14 15:05:46 -0700 |
| commit | dcad9ee9e0663d74a89b25b987f9c7be86432812 (patch) | |
| tree | ab35fda898b963d929da7fc6a42c9c08518b022e /net/core/dev.c | |
| parent | 102b55ee92f9fda4dde7a45d2b20538e6e3e3d1e (diff) | |
| download | linux-dcad9ee9e0663d74a89b25b987f9c7be86432812.tar.gz linux-dcad9ee9e0663d74a89b25b987f9c7be86432812.tar.bz2 linux-dcad9ee9e0663d74a89b25b987f9c7be86432812.zip | |
net: sched: fix tx action reschedule issue with stopped queue
The netdev qeueue might be stopped when byte queue limit has
reached or tx hw ring is full, net_tx_action() may still be
rescheduled if STATE_MISSED is set, which consumes unnecessary
cpu without dequeuing and transmiting any skb because the
netdev queue is stopped, see qdisc_run_end().
This patch fixes it by checking the netdev queue state before
calling qdisc_run() and clearing STATE_MISSED if netdev queue is
stopped during qdisc_run(), the net_tx_action() is rescheduled
again when netdev qeueue is restarted, see netif_tx_wake_queue().
As there is time window between netif_xmit_frozen_or_stopped()
checking and STATE_MISSED clearing, between which STATE_MISSED
may set by net_tx_action() scheduled by netif_tx_wake_queue(),
so set the STATE_MISSED again if netdev queue is restarted.
Fixes: 6b3ba9146fe6 ("net: sched: allow qdiscs to handle locking")
Reported-by: Michal Kubecek <mkubecek@suse.cz>
Acked-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Yunsheng Lin <linyunsheng@huawei.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/core/dev.c')
| -rw-r--r-- | net/core/dev.c | 3 |
1 files changed, 2 insertions, 1 deletions
diff --git a/net/core/dev.c b/net/core/dev.c index d596cd746353..ef8cf7619baf 100644 --- a/net/core/dev.c +++ b/net/core/dev.c @@ -3853,7 +3853,8 @@ static inline int __dev_xmit_skb(struct sk_buff *skb, struct Qdisc *q, if (q->flags & TCQ_F_NOLOCK) { rc = q->enqueue(skb, q, &to_free) & NET_XMIT_MASK; - qdisc_run(q); + if (likely(!netif_xmit_frozen_or_stopped(txq))) + qdisc_run(q); if (unlikely(to_free)) kfree_skb_list(to_free); |