net: ena: add jiffies of last napi call to stats

There are instances when we want to know when the last napi was
called for debugging.

On stuck / heavy loaded CPUs, the ena napi handler might not be
called for a long period of time. This stat can help us to
determine how much time passed since the last execution of napi.

Signed-off-by: Sameeh Jubran <sameehj@amazon.com>
Signed-off-by: Shay Agroskin <shayagr@amazon.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/drivers/net/ethernet/amazon/ena/ena_netdev.c b/drivers/net/ethernet/amazon/ena/ena_netdev.c
index d7bc4f4..f013fa3 100644 (file)
--- a/drivers/net/ethernet/amazon/ena/ena_netdev.c
+++ b/drivers/net/ethernet/amazon/ena/ena_netdev.c
@@ -228,6 +228,7 @@ static int ena_xdp_io_poll(struct napi_struct *napi, int budget)
        xdp_ring->tx_stats.napi_comp += napi_comp_call;
        xdp_ring->tx_stats.tx_poll++;
        u64_stats_update_end(&xdp_ring->syncp);
+       xdp_ring->tx_stats.last_napi_jiffies = jiffies;
 
        return ret;
 }
@@ -1989,6 +1990,8 @@ static int ena_io_poll(struct napi_struct *napi, int budget)
        tx_ring->tx_stats.tx_poll++;
        u64_stats_update_end(&tx_ring->syncp);
 
+       tx_ring->tx_stats.last_napi_jiffies = jiffies;
+
        return ret;
 }
 
@@ -3695,6 +3698,9 @@ static int check_missing_comp_in_tx_queue(struct ena_adapter *adapter,
                                          struct ena_ring *tx_ring)
 {
        struct ena_napi *ena_napi = container_of(tx_ring->napi, struct ena_napi, napi);
+       unsigned int time_since_last_napi;
+       unsigned int missing_tx_comp_to;
+       bool is_tx_comp_time_expired;
        struct ena_tx_buffer *tx_buf;
        unsigned long last_jiffies;
        u32 missed_tx = 0;
@@ -3708,9 +3714,10 @@ static int check_missing_comp_in_tx_queue(struct ena_adapter *adapter,
                        /* no pending Tx at this location */
                        continue;
 
-               if (unlikely(!READ_ONCE(ena_napi->first_interrupt) &&
-                       time_is_before_jiffies(last_jiffies + 2 *
-                               adapter->missing_tx_completion_to))) {
+               is_tx_comp_time_expired = time_is_before_jiffies(last_jiffies +
+                        2 * adapter->missing_tx_completion_to);
+
+               if (unlikely(!READ_ONCE(ena_napi->first_interrupt) && is_tx_comp_time_expired)) {
                        /* If after graceful period interrupt is still not
                         * received, we schedule a reset
                         */
@@ -3723,12 +3730,17 @@ static int check_missing_comp_in_tx_queue(struct ena_adapter *adapter,
                        return -EIO;
                }
 
-               if (unlikely(time_is_before_jiffies(last_jiffies +
-                               adapter->missing_tx_completion_to))) {
-                       if (!tx_buf->print_once)
+               is_tx_comp_time_expired = time_is_before_jiffies(last_jiffies +
+                       adapter->missing_tx_completion_to);
+
+               if (unlikely(is_tx_comp_time_expired)) {
+                       if (!tx_buf->print_once) {
+                               time_since_last_napi = jiffies_to_usecs(jiffies - tx_ring->tx_stats.last_napi_jiffies);
+                               missing_tx_comp_to = jiffies_to_msecs(adapter->missing_tx_completion_to);
                                netif_notice(adapter, tx_err, adapter->netdev,
-                                            "Found a Tx that wasn't completed on time, qid %d, index %d.\n",
-                                            tx_ring->qid, i);
+                                            "Found a Tx that wasn't completed on time, qid %d, index %d. %u usecs have passed since last napi execution. Missing Tx timeout value %u msecs\n",
+                                            tx_ring->qid, i, time_since_last_napi, missing_tx_comp_to);
+                       }
 
                        tx_buf->print_once = 1;
                        missed_tx++;

diff --git a/drivers/net/ethernet/amazon/ena/ena_netdev.h b/drivers/net/ethernet/amazon/ena/ena_netdev.h
index 834348f..0c39fc2 100644 (file)
--- a/drivers/net/ethernet/amazon/ena/ena_netdev.h
+++ b/drivers/net/ethernet/amazon/ena/ena_netdev.h
@@ -206,6 +206,7 @@ struct ena_stats_tx {
        u64 llq_buffer_copy;
        u64 missed_tx;
        u64 unmask_interrupt;
+       u64 last_napi_jiffies;
 };
 
 struct ena_stats_rx {