From bec251bc8b6ab83464f6fca6842ad4ee47307d2e Mon Sep 17 00:00:00 2001
From: Eric Dumazet <edumazet@google.com>
Date: Tue, 16 Nov 2021 19:29:24 -0800
Subject: [PATCH] net: no longer stop all TX queues in dev_watchdog()
There is no reason for stopping all TX queues from dev_watchdog()
Not only this stops feeding the NIC, it also migrates all qdiscs
to be serviced on the cpu calling netif_tx_unlock(), causing
a potential latency artifact.
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
---
net/sched/sch_generic.c | 8 +++++---
1 file changed, 5 insertions(+), 3 deletions(-)
diff --git a/net/sched/sch_generic.c b/net/sched/sch_generic.c
index 389e0d8fc68d..d33804d41c5c 100644
--- a/net/sched/sch_generic.c
+++ b/net/sched/sch_generic.c
@@ -500,7 +500,7 @@ static void dev_watchdog(struct timer_list *t)
{
struct net_device *dev = from_timer(dev, t, watchdog_timer);
- netif_tx_lock(dev);
+ spin_lock(&dev->tx_global_lock);
if (!qdisc_tx_is_noop(dev)) {
if (netif_device_present(dev) &&
netif_running(dev) &&
@@ -523,11 +523,13 @@ static void dev_watchdog(struct timer_list *t)
}
}
- if (some_queue_timedout) {
+ if (unlikely(some_queue_timedout)) {
trace_net_dev_xmit_timeout(dev, i);
WARN_ONCE(1, KERN_INFO "NETDEV WATCHDOG: %s (%s): transmit queue %u timed out\n",
dev->name, netdev_drivername(dev), i);
+ netif_freeze_queues(dev);
dev->netdev_ops->ndo_tx_timeout(dev, i);
+ netif_unfreeze_queues(dev);
}
if (!mod_timer(&dev->watchdog_timer,
round_jiffies(jiffies +
@@ -535,7 +537,7 @@ static void dev_watchdog(struct timer_list *t)
dev_hold(dev);
}
}
- netif_tx_unlock(dev);
+ spin_unlock(&dev->tx_global_lock);
dev_put(dev);
}