[PATCH net-next v7 4/5] net: sched: add timeout count to NETDEV WATCHDOG message

[hawk@kernel.org]

From: Jesper Dangaard Brouer <hawk@kernel.org>

Add the per-queue timeout counter (trans_timeout) to the core NETDEV
WATCHDOG log message.  This makes it easy to determine how frequently
a particular queue is stalling from a single log line, without having
to search through and correlate spaced-out log entries.

Useful for production monitoring where timeouts are spaced by the
watchdog interval, making frequency hard to judge.

Suggested-by: Jakub Kicinski <kuba@kernel.org>
Link: https://lore.kernel.org/all/20251107175445.58eba452@kernel.org/
Signed-off-by: Jesper Dangaard Brouer <hawk@kernel.org>
Tested-by: Jonas Köppeler <j.koeppeler@tu-berlin.de>
---
 net/sched/sch_generic.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/net/sched/sch_generic.c b/net/sched/sch_generic.c
index 237ee1cd0136..eb6066d1ed90 100644
--- a/net/sched/sch_generic.c
+++ b/net/sched/sch_generic.c
@@ -533,6 +533,7 @@ static void dev_watchdog(struct timer_list *t)
 		    netif_running(dev) &&
 		    netif_carrier_ok(dev)) {
 			unsigned int timedout_ms = 0;
+			unsigned long trans_timeout = 0;
 			unsigned int i;
 			unsigned long trans_start;
 			unsigned long oldest_start = jiffies;
@@ -553,6 +554,7 @@ static void dev_watchdog(struct timer_list *t)
 				if (time_after(jiffies, trans_start + dev->watchdog_timeo)) {
 					timedout_ms = jiffies_to_msecs(jiffies - trans_start);
 					atomic_long_inc(&txq->trans_timeout);
+					trans_timeout = atomic_long_read(&txq->trans_timeout);
 					break;
 				}
 				if (time_after(oldest_start, trans_start))
@@ -561,9 +563,9 @@ static void dev_watchdog(struct timer_list *t)
 
 			if (unlikely(timedout_ms)) {
 				trace_net_dev_xmit_timeout(dev, i);
-				netdev_crit(dev, "NETDEV WATCHDOG: CPU: %d: transmit queue %u timed out %u ms\n",
+				netdev_crit(dev, "NETDEV WATCHDOG: CPU: %d: transmit queue %u timed out %u ms (n:%ld)\n",
 					    raw_smp_processor_id(),
-					    i, timedout_ms);
+					    i, timedout_ms, trans_timeout);
 				netif_freeze_queues(dev);
 				dev->netdev_ops->ndo_tx_timeout(dev, i);
 				netif_unfreeze_queues(dev);
-- 
2.43.0