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Commit e08400b7 authored by Emil Tantilov's avatar Emil Tantilov Committed by Jeff Kirsher
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ixgbevf: Add code to check for Tx hang 



This patch adds code to allow for Tx hang checking.  The idea is to provide
more robust debug info in the event of a transmit unit hang. Similar to the
logic in ixgbe.

CC: Alexander Duyck <alexander.h.duyck@redhat.com>
Signed-off-by: default avatarEmil Tantilov <emil.s.tantilov@intel.com>
Tested-by: default avatarPhil Schmitt <phillip.j.schmitt@intel.com>
Signed-off-by: default avatarJeff Kirsher <jeffrey.t.kirsher@intel.com>
parent d9bdb57f

drivers/net/ethernet/intel/ixgbevf/ixgbevf.h

+20 −1
Original line number Diff line number Diff line
@@ -43,6 +43,13 @@ 
#define BP_EXTENDED_STATS

#endif



#define IXGBE_MAX_TXD_PWR	14

#define IXGBE_MAX_DATA_PER_TXD	BIT(IXGBE_MAX_TXD_PWR)



/* Tx Descriptors needed, worst case */

#define TXD_USE_COUNT(S) DIV_ROUND_UP((S), IXGBE_MAX_DATA_PER_TXD)

#define DESC_NEEDED (MAX_SKB_FRAGS + 4)



/* wrapper around a pointer to a socket buffer,

 * so a DMA handle can be stored along with the buffer */

struct ixgbevf_tx_buffer {
@@ -85,6 +92,18 @@ struct ixgbevf_rx_queue_stats { 
	u64 csum_err;

};



enum ixgbevf_ring_state_t {

	__IXGBEVF_TX_DETECT_HANG,

	__IXGBEVF_HANG_CHECK_ARMED,

};



#define check_for_tx_hang(ring) \

	test_bit(__IXGBEVF_TX_DETECT_HANG, &(ring)->state)

#define set_check_for_tx_hang(ring) \

	set_bit(__IXGBEVF_TX_DETECT_HANG, &(ring)->state)

#define clear_check_for_tx_hang(ring) \

	clear_bit(__IXGBEVF_TX_DETECT_HANG, &(ring)->state)



struct ixgbevf_ring {

	struct ixgbevf_ring *next;

	struct net_device *netdev;
@@ -101,7 +120,7 @@ struct ixgbevf_ring { 
		struct ixgbevf_tx_buffer *tx_buffer_info;

		struct ixgbevf_rx_buffer *rx_buffer_info;

	};



	unsigned long state;

	struct ixgbevf_stats stats;

	struct u64_stats_sync syncp;

	union {

drivers/net/ethernet/intel/ixgbevf/ixgbevf_main.c

+95 −18
Original line number Diff line number Diff line
@@ -199,14 +199,64 @@ static void ixgbevf_unmap_and_free_tx_resource(struct ixgbevf_ring *tx_ring, 
	/* tx_buffer must be completely set up in the transmit path */

}



#define IXGBE_MAX_TXD_PWR	14

#define IXGBE_MAX_DATA_PER_TXD	(1 << IXGBE_MAX_TXD_PWR)

static u64 ixgbevf_get_tx_completed(struct ixgbevf_ring *ring)

{

	return ring->stats.packets;

}



static u32 ixgbevf_get_tx_pending(struct ixgbevf_ring *ring)

{

	struct ixgbevf_adapter *adapter = netdev_priv(ring->netdev);

	struct ixgbe_hw *hw = &adapter->hw;



	u32 head = IXGBE_READ_REG(hw, IXGBE_VFTDH(ring->reg_idx));

	u32 tail = IXGBE_READ_REG(hw, IXGBE_VFTDT(ring->reg_idx));



	if (head != tail)

		return (head < tail) ?

			tail - head : (tail + ring->count - head);



	return 0;

}



static inline bool ixgbevf_check_tx_hang(struct ixgbevf_ring *tx_ring)

{

	u32 tx_done = ixgbevf_get_tx_completed(tx_ring);

	u32 tx_done_old = tx_ring->tx_stats.tx_done_old;

	u32 tx_pending = ixgbevf_get_tx_pending(tx_ring);



	clear_check_for_tx_hang(tx_ring);



	/* Check for a hung queue, but be thorough. This verifies

	 * that a transmit has been completed since the previous

	 * check AND there is at least one packet pending. The

	 * ARMED bit is set to indicate a potential hang.

	 */

	if ((tx_done_old == tx_done) && tx_pending) {

		/* make sure it is true for two checks in a row */

		return test_and_set_bit(__IXGBEVF_HANG_CHECK_ARMED,

					&tx_ring->state);

	}

	/* reset the countdown */

	clear_bit(__IXGBEVF_HANG_CHECK_ARMED, &tx_ring->state);



/* Tx Descriptors needed, worst case */

#define TXD_USE_COUNT(S) DIV_ROUND_UP((S), IXGBE_MAX_DATA_PER_TXD)

#define DESC_NEEDED (MAX_SKB_FRAGS + 4)

	/* update completed stats and continue */

	tx_ring->tx_stats.tx_done_old = tx_done;



static void ixgbevf_tx_timeout(struct net_device *netdev);

	return false;

}



/**

 * ixgbevf_tx_timeout - Respond to a Tx Hang

 * @netdev: network interface device structure

 **/

static void ixgbevf_tx_timeout(struct net_device *netdev)

{

	struct ixgbevf_adapter *adapter = netdev_priv(netdev);



	/* Do the reset outside of interrupt context */

	schedule_work(&adapter->reset_task);

}



/**

 * ixgbevf_clean_tx_irq - Reclaim resources after transmit completes
@@ -311,6 +361,37 @@ static bool ixgbevf_clean_tx_irq(struct ixgbevf_q_vector *q_vector, 
	q_vector->tx.total_bytes += total_bytes;

	q_vector->tx.total_packets += total_packets;



	if (check_for_tx_hang(tx_ring) && ixgbevf_check_tx_hang(tx_ring)) {

		struct ixgbe_hw *hw = &adapter->hw;

		union ixgbe_adv_tx_desc *eop_desc;



		eop_desc = tx_ring->tx_buffer_info[i].next_to_watch;



		pr_err("Detected Tx Unit Hang\n"

		       "  Tx Queue             <%d>\n"

		       "  TDH, TDT             <%x>, <%x>\n"

		       "  next_to_use          <%x>\n"

		       "  next_to_clean        <%x>\n"

		       "tx_buffer_info[next_to_clean]\n"

		       "  next_to_watch        <%p>\n"

		       "  eop_desc->wb.status  <%x>\n"

		       "  time_stamp           <%lx>\n"

		       "  jiffies              <%lx>\n",

		       tx_ring->queue_index,

		       IXGBE_READ_REG(hw, IXGBE_VFTDH(tx_ring->reg_idx)),

		       IXGBE_READ_REG(hw, IXGBE_VFTDT(tx_ring->reg_idx)),

		       tx_ring->next_to_use, i,

		       eop_desc, (eop_desc ? eop_desc->wb.status : 0),

		       tx_ring->tx_buffer_info[i].time_stamp, jiffies);



		netif_stop_subqueue(tx_ring->netdev, tx_ring->queue_index);



		/* schedule immediate reset if we believe we hung */

		schedule_work(&adapter->reset_task);



		return true;

	}



#define TX_WAKE_THRESHOLD (DESC_NEEDED * 2)

	if (unlikely(total_packets && netif_carrier_ok(tx_ring->netdev) &&

		     (ixgbevf_desc_unused(tx_ring) >= TX_WAKE_THRESHOLD))) {
@@ -1479,6 +1560,8 @@ static void ixgbevf_configure_tx_ring(struct ixgbevf_adapter *adapter, 
	txdctl |= (1 << 8) |    /* HTHRESH = 1 */

		  32;          /* PTHRESH = 32 */



	clear_bit(__IXGBEVF_HANG_CHECK_ARMED, &ring->state);



	IXGBE_WRITE_REG(hw, IXGBE_VFTXDCTL(reg_idx), txdctl);



	/* poll to verify queue is enabled */
@@ -2643,6 +2726,12 @@ static void ixgbevf_watchdog(unsigned long data) 
	if (test_bit(__IXGBEVF_DOWN, &adapter->state))

		goto watchdog_short_circuit;



	/* Force detection of hung controller */

	if (netif_carrier_ok(adapter->netdev)) {

		for (i = 0; i < adapter->num_tx_queues; i++)

			set_check_for_tx_hang(adapter->tx_ring[i]);

	}



	/* get one bit for every active tx/rx interrupt vector */

	for (i = 0; i < adapter->num_msix_vectors - NON_Q_VECTORS; i++) {

		struct ixgbevf_q_vector *qv = adapter->q_vector[i];
@@ -2656,18 +2745,6 @@ static void ixgbevf_watchdog(unsigned long data) 
	schedule_work(&adapter->watchdog_task);

}



/**

 * ixgbevf_tx_timeout - Respond to a Tx Hang

 * @netdev: network interface device structure

 **/

static void ixgbevf_tx_timeout(struct net_device *netdev)

{

	struct ixgbevf_adapter *adapter = netdev_priv(netdev);



	/* Do the reset outside of interrupt context */

	schedule_work(&adapter->reset_task);

}



static void ixgbevf_reset_task(struct work_struct *work)

{

	struct ixgbevf_adapter *adapter;