net: new counter for tx_timeout errors in sysfs

This adds the /sys/class/net/DEV/queues/Q/tx_timeout attribute
containing the total number of timeout events on the given queue. It
is always available with CONFIG_SYSFS, independently of
CONFIG_RPS/XPS.

Credits to Stephen Hemminger for a preliminary version of this patch.

Tested:
  without CONFIG_SYSFS (compilation only)
  with sysfs and without CONFIG_RPS & CONFIG_XPS
  with sysfs and without CONFIG_RPS
  with sysfs and without CONFIG_XPS
  with defaults

Signed-off-by: David Decotigny <david.decotigny@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 10 insertions, 2 deletions

diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h
index 31da3bbe7b1b..4d5698aa828b 100644
--- a/include/linux/netdevice.h
+++ b/include/linux/netdevice.h
@@ -532,7 +532,7 @@ struct netdev_queue {
         struct Qdisc            *qdisc;
         unsigned long           state;
         struct Qdisc            *qdisc_sleeping;
-#if defined(CONFIG_RPS) || defined(CONFIG_XPS)
+#ifdef CONFIG_SYSFS
         struct kobject          kobj;
 #endif
 #if defined(CONFIG_XPS) && defined(CONFIG_NUMA)
@@ -547,6 +547,12 @@ struct netdev_queue {
          * please use this field instead of dev->trans_start
          */
         unsigned long           trans_start;
+
+        /*
+         * Number of TX timeouts for this queue
+         * (/sys/class/net/DEV/Q/trans_timeout)
+         */
+        unsigned long           trans_timeout;
 } ____cacheline_aligned_in_smp;
 
 static inline int netdev_queue_numa_node_read(const struct netdev_queue *q)
@@ -1109,9 +1115,11 @@ struct net_device {
 
         unsigned char           broadcast[MAX_ADDR_LEN];        /* hw bcast add */
 
-#if defined(CONFIG_RPS) || defined(CONFIG_XPS)
+#ifdef CONFIG_SYSFS
         struct kset             *queues_kset;
+#endif
 
+#ifdef CONFIG_RPS
         struct netdev_rx_queue  *_rx;
 
         /* Number of RX queues allocated at register_netdev() time */