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* [dpdk-dev] [PATCH v4 1/2] net/mlx5: link status update separation
@ 2017-09-06 15:03 Matan Azrad
  2017-09-06 15:03 ` [dpdk-dev] [PATCH v4 2/2] net/mlx5: support device removal event Matan Azrad
  2017-09-06 15:14 ` [dpdk-dev] [PATCH v4 1/2] net/mlx5: link status update separation Adrien Mazarguil
  0 siblings, 2 replies; 8+ messages in thread
From: Matan Azrad @ 2017-09-06 15:03 UTC (permalink / raw)
  To: Nelio Laranjeiro, Adrien Mazarguil; +Cc: dev

Link status is sometimes inconsistent during a LSC event.
When it occurs, the PMD refrains from immediately notifying
the application; instead, an alarm is scheduled to check
link status later and notify the application once it has settled.

In the previous code the alarm callback calls to the interrupt
handler for link status recheck and may cause to unnecessary
interrupt events check.

This patch separates the link status update and the interrupt event
handler to avoid the unnecessary check and arranges the interrupt
handler for more interrupt supports in the future.

Comment was added in the new function to explain the inconsistent
link status reason.

Signed-off-by: Matan Azrad <matan@mellanox.com>
---
 drivers/net/mlx5/mlx5_ethdev.c | 83 ++++++++++++++++++++++++++++--------------
 1 file changed, 55 insertions(+), 28 deletions(-)

Changes:
V2:
Replace link status update function name.
Add inconsistent link workaround comment.

V3:
Fix indentations.
Accurate inconsistent link comment.

V4:
Separate the patch.
Short the comment.

diff --git a/drivers/net/mlx5/mlx5_ethdev.c b/drivers/net/mlx5/mlx5_ethdev.c
index 57f6237..64a8db8 100644
--- a/drivers/net/mlx5/mlx5_ethdev.c
+++ b/drivers/net/mlx5/mlx5_ethdev.c
@@ -1112,47 +1112,74 @@ mlx5_ibv_device_to_pci_addr(const struct ibv_device *device,
 }
 
 /**
- * Link status handler.
+ * Update the link status.
  *
  * @param priv
  *   Pointer to private structure.
- * @param dev
- *   Pointer to the rte_eth_dev structure.
  *
  * @return
- *   Nonzero if the callback process can be called immediately.
+ *   Zero if the callback process can be called immediately.
  */
 static int
-priv_dev_link_status_handler(struct priv *priv, struct rte_eth_dev *dev)
+priv_link_status_update(struct priv *priv)
+{
+	struct rte_eth_link *link = &priv->dev->data->dev_link;
+
+	mlx5_link_update(priv->dev, 0);
+	if (((link->link_speed == 0) && link->link_status) ||
+		((link->link_speed != 0) && !link->link_status)) {
+		/*
+		 * Inconsistent status. Event likely occurred before the
+		 * kernel netdevice exposes the new status.
+		 */
+		if (!priv->pending_alarm) {
+			priv->pending_alarm = 1;
+			rte_eal_alarm_set(MLX5_ALARM_TIMEOUT_US,
+					  mlx5_dev_link_status_handler,
+					  priv->dev);
+		}
+		return 1;
+	} else if (unlikely(priv->pending_alarm)) {
+		/* Link interrupt occurred while alarm is already scheduled. */
+		priv->pending_alarm = 0;
+		rte_eal_alarm_cancel(mlx5_dev_link_status_handler, priv->dev);
+	}
+	return 0;
+}
+
+/**
+ * Device status handler.
+ *
+ * @param priv
+ *   Pointer to private structure.
+ * @param events
+ *   Pointer to event flags holder.
+ *
+ * @return
+ *   Events bitmap of callback process which can be called immediately.
+ */
+static uint32_t
+priv_dev_status_handler(struct priv *priv)
 {
 	struct ibv_async_event event;
-	struct rte_eth_link *link = &dev->data->dev_link;
-	int ret = 0;
+	uint32_t ret = 0;
 
 	/* Read all message and acknowledge them. */
 	for (;;) {
 		if (ibv_get_async_event(priv->ctx, &event))
 			break;
-
-		if (event.event_type != IBV_EVENT_PORT_ACTIVE &&
-		    event.event_type != IBV_EVENT_PORT_ERR)
+		if ((event.event_type == IBV_EVENT_PORT_ACTIVE ||
+			event.event_type == IBV_EVENT_PORT_ERR) &&
+			(priv->dev->data->dev_conf.intr_conf.lsc == 1))
+			ret |= (1 << RTE_ETH_EVENT_INTR_LSC);
+		else
 			DEBUG("event type %d on port %d not handled",
 			      event.event_type, event.element.port_num);
 		ibv_ack_async_event(&event);
 	}
-	mlx5_link_update(dev, 0);
-	if (((link->link_speed == 0) && link->link_status) ||
-	    ((link->link_speed != 0) && !link->link_status)) {
-		if (!priv->pending_alarm) {
-			/* Inconsistent status, check again later. */
-			priv->pending_alarm = 1;
-			rte_eal_alarm_set(MLX5_ALARM_TIMEOUT_US,
-					  mlx5_dev_link_status_handler,
-					  dev);
-		}
-	} else {
-		ret = 1;
-	}
+	if (ret & (1 << RTE_ETH_EVENT_INTR_LSC))
+		if (priv_link_status_update(priv))
+			ret &= ~(1 << RTE_ETH_EVENT_INTR_LSC);
 	return ret;
 }
 
@@ -1172,9 +1199,9 @@ mlx5_dev_link_status_handler(void *arg)
 	priv_lock(priv);
 	assert(priv->pending_alarm == 1);
 	priv->pending_alarm = 0;
-	ret = priv_dev_link_status_handler(priv, dev);
+	ret = priv_link_status_update(priv);
 	priv_unlock(priv);
-	if (ret)
+	if (!ret)
 		_rte_eth_dev_callback_process(dev, RTE_ETH_EVENT_INTR_LSC, NULL,
 					      NULL);
 }
@@ -1192,12 +1219,12 @@ mlx5_dev_interrupt_handler(void *cb_arg)
 {
 	struct rte_eth_dev *dev = cb_arg;
 	struct priv *priv = dev->data->dev_private;
-	int ret;
+	uint32_t events;
 
 	priv_lock(priv);
-	ret = priv_dev_link_status_handler(priv, dev);
+	events = priv_dev_status_handler(priv);
 	priv_unlock(priv);
-	if (ret)
+	if (events & (1 << RTE_ETH_EVENT_INTR_LSC))
 		_rte_eth_dev_callback_process(dev, RTE_ETH_EVENT_INTR_LSC, NULL,
 					      NULL);
 }
-- 
2.7.4

^ permalink raw reply	[flat|nested] 8+ messages in thread
end of thread, other threads:[~2017-09-11 16:13 UTC | newest]

Thread overview: 8+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2017-09-06 15:03 [dpdk-dev] [PATCH v4 1/2] net/mlx5: link status update separation Matan Azrad
2017-09-06 15:03 ` [dpdk-dev] [PATCH v4 2/2] net/mlx5: support device removal event Matan Azrad
2017-09-06 15:14   ` Adrien Mazarguil
2017-09-08 10:05   ` Ferruh Yigit
2017-09-08 10:47   ` [dpdk-dev] [PATCH v5] " Matan Azrad
2017-09-11 16:12     ` Ferruh Yigit
2017-09-06 15:14 ` [dpdk-dev] [PATCH v4 1/2] net/mlx5: link status update separation Adrien Mazarguil
2017-09-11 16:12   ` Ferruh Yigit

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