diff mbox

[1/2,net] ibmvnic: Fix overflowing firmware/hardware TX queue

Message ID 1488737922-17305-1-git-send-email-tlfalcon@linux.vnet.ibm.com
State Accepted, archived
Delegated to: David Miller
Headers show

Commit Message

Thomas Falcon March 5, 2017, 6:18 p.m. UTC
Use a counter to track the number of outstanding transmissions sent
that have not received completions. If the counter reaches the maximum
number of queue entries, stop transmissions on that queue. As we receive 
more completions from firmware, wake the queue once the counter reaches 
an acceptable level.

This patch prevents hardware/firmware TX queue from filling up and
and generating errors.  Since incorporating this fix, internal testing
has reported that these firmware errors have stopped.

Signed-off-by: Thomas Falcon <tlfalcon@linux.vnet.ibm.com>
---
 drivers/net/ethernet/ibm/ibmvnic.c | 27 ++++++++++++++++++++++++++-
 drivers/net/ethernet/ibm/ibmvnic.h |  1 +
 2 files changed, 27 insertions(+), 1 deletion(-)

Comments

David Miller March 7, 2017, 10:14 p.m. UTC | #1
From: Thomas Falcon <tlfalcon@linux.vnet.ibm.com>
Date: Sun,  5 Mar 2017 12:18:41 -0600

> Use a counter to track the number of outstanding transmissions sent
> that have not received completions. If the counter reaches the maximum
> number of queue entries, stop transmissions on that queue. As we receive 
> more completions from firmware, wake the queue once the counter reaches 
> an acceptable level.
> 
> This patch prevents hardware/firmware TX queue from filling up and
> and generating errors.  Since incorporating this fix, internal testing
> has reported that these firmware errors have stopped.
> 
> Signed-off-by: Thomas Falcon <tlfalcon@linux.vnet.ibm.com>

Applied.
diff mbox

Patch

diff --git a/drivers/net/ethernet/ibm/ibmvnic.c b/drivers/net/ethernet/ibm/ibmvnic.c
index 9198e6b..0e87b83 100644
--- a/drivers/net/ethernet/ibm/ibmvnic.c
+++ b/drivers/net/ethernet/ibm/ibmvnic.c
@@ -705,6 +705,7 @@  static int ibmvnic_xmit(struct sk_buff *skb, struct net_device *netdev)
 	u8 *hdrs = (u8 *)&adapter->tx_rx_desc_req;
 	struct device *dev = &adapter->vdev->dev;
 	struct ibmvnic_tx_buff *tx_buff = NULL;
+	struct ibmvnic_sub_crq_queue *tx_scrq;
 	struct ibmvnic_tx_pool *tx_pool;
 	unsigned int tx_send_failed = 0;
 	unsigned int tx_map_failed = 0;
@@ -724,6 +725,7 @@  static int ibmvnic_xmit(struct sk_buff *skb, struct net_device *netdev)
 	int ret = 0;
 
 	tx_pool = &adapter->tx_pool[queue_num];
+	tx_scrq = adapter->tx_scrq[queue_num];
 	txq = netdev_get_tx_queue(netdev, skb_get_queue_mapping(skb));
 	handle_array = (u64 *)((u8 *)(adapter->login_rsp_buf) +
 				   be32_to_cpu(adapter->login_rsp_buf->
@@ -826,6 +828,14 @@  static int ibmvnic_xmit(struct sk_buff *skb, struct net_device *netdev)
 		ret = NETDEV_TX_BUSY;
 		goto out;
 	}
+
+	atomic_inc(&tx_scrq->used);
+
+	if (atomic_read(&tx_scrq->used) >= adapter->req_tx_entries_per_subcrq) {
+		netdev_info(netdev, "Stopping queue %d\n", queue_num);
+		netif_stop_subqueue(netdev, queue_num);
+	}
+
 	tx_packets++;
 	tx_bytes += skb->len;
 	txq->trans_start = jiffies;
@@ -1213,6 +1223,7 @@  static struct ibmvnic_sub_crq_queue *init_sub_crq_queue(struct ibmvnic_adapter
 	scrq->adapter = adapter;
 	scrq->size = 4 * PAGE_SIZE / sizeof(*scrq->msgs);
 	scrq->cur = 0;
+	atomic_set(&scrq->used, 0);
 	scrq->rx_skb_top = NULL;
 	spin_lock_init(&scrq->lock);
 
@@ -1355,8 +1366,22 @@  static int ibmvnic_complete_tx(struct ibmvnic_adapter *adapter,
 						 DMA_TO_DEVICE);
 			}
 
-			if (txbuff->last_frag)
+			if (txbuff->last_frag) {
+				atomic_dec(&scrq->used);
+
+				if (atomic_read(&scrq->used) <=
+				    (adapter->req_tx_entries_per_subcrq / 2) &&
+				    netif_subqueue_stopped(adapter->netdev,
+							   txbuff->skb)) {
+					netif_wake_subqueue(adapter->netdev,
+							    scrq->pool_index);
+					netdev_dbg(adapter->netdev,
+						   "Started queue %d\n",
+						   scrq->pool_index);
+				}
+
 				dev_kfree_skb_any(txbuff->skb);
+			}
 
 			adapter->tx_pool[pool].free_map[adapter->tx_pool[pool].
 						     producer_index] = index;
diff --git a/drivers/net/ethernet/ibm/ibmvnic.h b/drivers/net/ethernet/ibm/ibmvnic.h
index 422824f..1993b42 100644
--- a/drivers/net/ethernet/ibm/ibmvnic.h
+++ b/drivers/net/ethernet/ibm/ibmvnic.h
@@ -863,6 +863,7 @@  struct ibmvnic_sub_crq_queue {
 	spinlock_t lock;
 	struct sk_buff *rx_skb_top;
 	struct ibmvnic_adapter *adapter;
+	atomic_t used;
 };
 
 struct ibmvnic_long_term_buff {