@@ -94,6 +94,7 @@ static const struct ena_stats ena_stats_rx_strings[] = {
ENA_STAT_RX_ENTRY(dma_mapping_err),
ENA_STAT_RX_ENTRY(bad_desc_num),
ENA_STAT_RX_ENTRY(rx_copybreak_pkt),
+ ENA_STAT_RX_ENTRY(empty_rx_ring),
};
static const struct ena_stats ena_stats_ena_com_strings[] = {
@@ -190,6 +190,7 @@ static void ena_init_io_rings(struct ena_adapter *adapter)
rxr->sgl_size = adapter->max_rx_sgl_size;
rxr->smoothed_interval =
ena_com_get_nonadaptive_moderation_interval_rx(ena_dev);
+ rxr->empty_rx_queue = 0;
}
}
@@ -2619,6 +2620,58 @@ static void check_for_missing_tx_completions(struct ena_adapter *adapter)
adapter->last_monitored_tx_qid = i % adapter->num_queues;
}
+/* trigger napi schedule after 2 consecutive detections */
+#define EMPTY_RX_REFILL 2
+/* For the rare case where the device runs out of Rx descriptors and the
+ * napi handler failed to refill new Rx descriptors (due to a lack of memory
+ * for example).
+ * This case will lead to a deadlock:
+ * The device won't send interrupts since all the new Rx packets will be dropped
+ * The napi handler won't allocate new Rx descriptors so the device will be
+ * able to send new packets.
+ *
+ * This scenario can happen when the kernel's vm.min_free_kbytes is too small.
+ * It is recommended to have at least 512MB, with a minimum of 128MB for
+ * constrained environment).
+ *
+ * When such a situation is detected - Reschedule napi
+ */
+static void check_for_empty_rx_ring(struct ena_adapter *adapter)
+{
+ struct ena_ring *rx_ring;
+ int i, refill_required;
+
+ if (!test_bit(ENA_FLAG_DEV_UP, &adapter->flags))
+ return;
+
+ if (test_bit(ENA_FLAG_TRIGGER_RESET, &adapter->flags))
+ return;
+
+ for (i = 0; i < adapter->num_queues; i++) {
+ rx_ring = &adapter->rx_ring[i];
+
+ refill_required =
+ ena_com_sq_empty_space(rx_ring->ena_com_io_sq);
+ if (unlikely(refill_required == (rx_ring->ring_size - 1))) {
+ rx_ring->empty_rx_queue++;
+
+ if (rx_ring->empty_rx_queue >= EMPTY_RX_REFILL) {
+ u64_stats_update_begin(&rx_ring->syncp);
+ rx_ring->rx_stats.empty_rx_ring++;
+ u64_stats_update_end(&rx_ring->syncp);
+
+ netif_err(adapter, drv, adapter->netdev,
+ "trigger refill for ring %d\n", i);
+
+ napi_schedule(rx_ring->napi);
+ rx_ring->empty_rx_queue = 0;
+ }
+ } else {
+ rx_ring->empty_rx_queue = 0;
+ }
+ }
+}
+
/* Check for keep alive expiration */
static void check_for_missing_keep_alive(struct ena_adapter *adapter)
{
@@ -2673,6 +2726,8 @@ static void ena_timer_service(unsigned long data)
check_for_missing_tx_completions(adapter);
+ check_for_empty_rx_ring(adapter);
+
if (debug_area)
ena_dump_stats_to_buf(adapter, debug_area);
@@ -184,6 +184,7 @@ struct ena_stats_rx {
u64 dma_mapping_err;
u64 bad_desc_num;
u64 rx_copybreak_pkt;
+ u64 empty_rx_ring;
};
struct ena_ring {
@@ -231,6 +232,7 @@ struct ena_ring {
struct ena_stats_tx tx_stats;
struct ena_stats_rx rx_stats;
};
+ int empty_rx_queue;
} ____cacheline_aligned;
struct ena_stats_dev {