diff options
| author | Eric Dumazet <edumazet@google.com> | 2026-03-07 16:34:30 +0000 |
|---|---|---|
| committer | Jakub Kicinski <kuba@kernel.org> | 2026-03-09 18:55:55 -0700 |
| commit | 47e8dbb6e763e5ccfed2ab4aa55cbb163382aec1 (patch) | |
| tree | d3f680a255a0dce919442e8f1d780c508e6049c5 /net/core | |
| parent | 82f36517a13e6339ddd9737d8a310949e057e596 (diff) | |
net/sched: do not reset queues in graft operations
Following typical script is extremely disruptive,
because each graft operation calls dev_deactivate()
which resets all the queues of the device.
QPARAM="limit 100000 flow_limit 1000 buckets 4096"
TXQS=64
for ETH in eth1
do
tc qd del dev $ETH root 2>/dev/null
tc qd add dev $ETH root handle 1: mq
for i in `seq 1 $TXQS`
do
slot=$( printf %x $(( i )) )
tc qd add dev $ETH parent 1:$slot fq $QPARAM
done
done
One can add "ip link set dev $ETH down/up" to reduce the disruption time:
QPARAM="limit 100000 flow_limit 1000 buckets 4096"
TXQS=64
for ETH in eth1
do
ip link set dev $ETH down
tc qd del dev $ETH root 2>/dev/null
tc qd add dev $ETH root handle 1: mq
for i in `seq 1 $TXQS`
do
slot=$( printf %x $(( i )) )
tc qd add dev $ETH parent 1:$slot fq $QPARAM
done
ip link set dev $ETH up
done
Or we can add a @reset_needed flag to dev_deactivate() and
dev_deactivate_many().
This flag is set to true at device dismantle or linkwatch_do_dev(),
and to false for graft operations.
In the future, we might only stop one queue instead of the whole
device, ie call dev_deactivate_queue() instead of dev_deactivate().
I think the problem (quadratic behavior) was added in commit
2fb541c862c9 ("net: sch_generic: aviod concurrent reset and enqueue op
for lockless qdisc") but this does not look serious enough to deserve
risky backports.
Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Yunsheng Lin <linyunsheng@huawei.com>
Reviewed-by: Jamal Hadi Salim <jhs@mojatatu.com>
Reviewed-by: Toke Høiland-Jørgensen <toke@redhat.com>
Reviewed-by: Victor Nogueira <victor@mojatatu.com>
Link: https://patch.msgid.link/20260307163430.470644-1-edumazet@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Diffstat (limited to 'net/core')
| -rw-r--r-- | net/core/dev.c | 2 | ||||
| -rw-r--r-- | net/core/link_watch.c | 2 |
2 files changed, 2 insertions, 2 deletions
diff --git a/net/core/dev.c b/net/core/dev.c index 203dc36aaed5..6fc9350f0be8 100644 --- a/net/core/dev.c +++ b/net/core/dev.c @@ -1756,7 +1756,7 @@ static void __dev_close_many(struct list_head *head) smp_mb__after_atomic(); /* Commit netif_running(). */ } - dev_deactivate_many(head); + dev_deactivate_many(head, true); list_for_each_entry(dev, head, close_list) { const struct net_device_ops *ops = dev->netdev_ops; diff --git a/net/core/link_watch.c b/net/core/link_watch.c index 25c455c10a01..ff2c1d4538ef 100644 --- a/net/core/link_watch.c +++ b/net/core/link_watch.c @@ -181,7 +181,7 @@ static void linkwatch_do_dev(struct net_device *dev) if (netif_carrier_ok(dev)) dev_activate(dev); else - dev_deactivate(dev); + dev_deactivate(dev, true); netif_state_change(dev); } |