diff mbox series

[net-next,4/4] net: no longer stop all TX queues in dev_watchdog()

Message ID 20211117032924.1740327-5-eric.dumazet@gmail.com (mailing list archive)
State Accepted
Commit bec251bc8b6ab83464f6fca6842ad4ee47307d2e
Delegated to: Netdev Maintainers
Headers show
Series net: make dev_watchdog() less intrusive | expand

Checks

Context Check Description
netdev/tree_selection success Clearly marked for net-next
netdev/fixes_present success Fixes tag not required for -next series
netdev/subject_prefix success Link
netdev/cover_letter success Series has a cover letter
netdev/patch_count success Link
netdev/header_inline success No static functions without inline keyword in header files
netdev/build_32bit success Errors and warnings before: 8 this patch: 8
netdev/cc_maintainers warning 3 maintainers not CCed: xiyou.wangcong@gmail.com jiri@resnulli.us jhs@mojatatu.com
netdev/build_clang success Errors and warnings before: 22 this patch: 22
netdev/module_param success Was 0 now: 0
netdev/verify_signedoff success Signed-off-by tag matches author and committer
netdev/verify_fixes success No Fixes tag
netdev/build_allmodconfig_warn success Errors and warnings before: 12 this patch: 12
netdev/checkpatch success total: 0 errors, 0 warnings, 0 checks, 30 lines checked
netdev/kdoc success Errors and warnings before: 0 this patch: 0
netdev/source_inline success Was 0 now: 0

Commit Message

Eric Dumazet Nov. 17, 2021, 3:29 a.m. UTC 
From: Eric Dumazet <edumazet@google.com>

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>
---
 net/sched/sch_generic.c | 8 +++++---
 1 file changed, 5 insertions(+), 3 deletions(-)
diff mbox series

Patch

diff --git a/net/sched/sch_generic.c b/net/sched/sch_generic.c
index 389e0d8fc68d12cf092a975511729a8dae1b29fb..d33804d41c5c5a9047c808fd37ba65ae8875fc79 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);
 }