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Commit 9c6c1259 authored by Kiran Patil's avatar Kiran Patil Committed by Jeff Kirsher
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i40e: Detection and recovery of TX queue hung logic moved to service_task from tx_timeout 



This patch contains following changes:
   - detection and recovery logic (issue SW interrupt) has been moved to
     service_task from timeout function.
   - added some more debug info from tx_timeout.

Logic to detect and recover TX queue hung is now two step process:
  - service_task detects TX queue hung and sets a bit(hung_detected) if
    it was not set.
  - if bit was set (means this is back-back hung condition detected),
    issue SW interrupt and clear the bit.
  - napi_poll clears the bit unconditionally since it cleans TX/RX queues.

Change-ID: Ieed03a48927c845a988b3ff375090bf37caeb903
Signed-off-by: default avatarKiran Patil <kiran.patil@intel.com>
Tested-by: default avatarAndrew Bowers <andrewx.bowers@intel.com>
Signed-off-by: default avatarJeff Kirsher <jeffrey.t.kirsher@intel.com>
parent 05281eb8

drivers/net/ethernet/intel/i40e/i40e.h

+3 −0
Original line number Diff line number Diff line
@@ -579,6 +579,9 @@ struct i40e_q_vector { 


	u8 num_ringpairs;	/* total number of ring pairs in vector */



#define I40E_Q_VECTOR_HUNG_DETECT 0 /* Bit Index for hung detection logic */

	unsigned long hung_detected; /* Set/Reset for hung_detection logic */



	cpumask_t affinity_mask;

	struct rcu_head rcu;	/* to avoid race with update stats on free */

	char name[I40E_INT_NAME_STR_LEN];

drivers/net/ethernet/intel/i40e/i40e_main.c

+30 −6
Original line number Diff line number Diff line
@@ -4368,17 +4368,41 @@ static void i40e_detect_recover_hung_queue(int q_idx, struct i40e_vsi *vsi) 
	else

		val = rd32(&pf->hw, I40E_PFINT_DYN_CTL0);



	/* Bail out if interrupts are disabled because napi_poll

	 * execution in-progress or will get scheduled soon.

	 * napi_poll cleans TX and RX queues and updates 'next_to_clean'.

	 */

	if (!(val & I40E_PFINT_DYN_CTLN_INTENA_MASK))

		return;



	head = i40e_get_head(tx_ring);



	tx_pending = i40e_get_tx_pending(tx_ring);



	/* Interrupts are disabled and TX pending is non-zero,

	 * trigger the SW interrupt (don't wait). Worst case

	 * there will be one extra interrupt which may result

	 * into not cleaning any queues because queues are cleaned.

	/* HW is done executing descriptors, updated HEAD write back,

	 * but SW hasn't processed those descriptors. If interrupt is

	 * not generated from this point ON, it could result into

	 * dev_watchdog detecting timeout on those netdev_queue,

	 * hence proactively trigger SW interrupt.

	 */

	if (tx_pending && (!(val & I40E_PFINT_DYN_CTLN_INTENA_MASK)))

	if (tx_pending) {

		/* NAPI Poll didn't run and clear since it was set */

		if (test_and_clear_bit(I40E_Q_VECTOR_HUNG_DETECT,

				       &tx_ring->q_vector->hung_detected)) {

			netdev_info(vsi->netdev, "VSI_seid %d, Hung TX queue %d, tx_pending: %d, NTC:0x%x, HWB: 0x%x, NTU: 0x%x, TAIL: 0x%x\n",

				    vsi->seid, q_idx, tx_pending,

				    tx_ring->next_to_clean, head,

				    tx_ring->next_to_use,

				    readl(tx_ring->tail));

			netdev_info(vsi->netdev, "VSI_seid %d, Issuing force_wb for TX queue %d, Interrupt Reg: 0x%x\n",

				    vsi->seid, q_idx, val);

			i40e_force_wb(vsi, tx_ring->q_vector);

		} else {

			/* First Chance - detected possible hung */

			set_bit(I40E_Q_VECTOR_HUNG_DETECT,

				&tx_ring->q_vector->hung_detected);

		}

	}

}



/**

drivers/net/ethernet/intel/i40e/i40e_txrx.c

+2 −0
Original line number Diff line number Diff line
@@ -1891,6 +1891,8 @@ int i40e_napi_poll(struct napi_struct *napi, int budget) 
		return 0;

	}



	/* Clear hung_detected bit */

	clear_bit(I40E_Q_VECTOR_HUNG_DETECT, &q_vector->hung_detected);

	/* Since the actual Tx work is minimal, we can give the Tx a larger

	 * budget and be more aggressive about cleaning up the Tx descriptors.

	 */

drivers/net/ethernet/intel/i40evf/i40e_txrx.c

+14 −7
Original line number Diff line number Diff line
@@ -127,17 +127,24 @@ void i40evf_free_tx_resources(struct i40e_ring *tx_ring) 
}



/**

 * i40e_get_head - Retrieve head from head writeback

 * @tx_ring:  tx ring to fetch head of

 * i40evf_get_tx_pending - how many Tx descriptors not processed

 * @tx_ring: the ring of descriptors

 *

 * Returns value of Tx ring head based on value stored

 * in head write-back location

 * Since there is no access to the ring head register

 * in XL710, we need to use our local copies

 **/

static inline u32 i40e_get_head(struct i40e_ring *tx_ring)

u32 i40evf_get_tx_pending(struct i40e_ring *ring)

{

	void *head = (struct i40e_tx_desc *)tx_ring->desc + tx_ring->count;

	u32 head, tail;



	return le32_to_cpu(*(volatile __le32 *)head);

	head = i40e_get_head(ring);

	tail = readl(ring->tail);



	if (head != tail)

		return (head < tail) ?

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



	return 0;

}



#define WB_STRIDE 0x3

drivers/net/ethernet/intel/i40evf/i40e_txrx.h

+15 −0
Original line number Diff line number Diff line
@@ -324,4 +324,19 @@ int i40evf_setup_rx_descriptors(struct i40e_ring *rx_ring); 
void i40evf_free_tx_resources(struct i40e_ring *tx_ring);

void i40evf_free_rx_resources(struct i40e_ring *rx_ring);

int i40evf_napi_poll(struct napi_struct *napi, int budget);

u32 i40evf_get_tx_pending(struct i40e_ring *ring);



/**

 * i40e_get_head - Retrieve head from head writeback

 * @tx_ring: Tx ring to fetch head of

 *

 * Returns value of Tx ring head based on value stored

 * in head write-back location

 **/

static inline u32 i40e_get_head(struct i40e_ring *tx_ring)

{

	void *head = (struct i40e_tx_desc *)tx_ring->desc + tx_ring->count;



	return le32_to_cpu(*(volatile __le32 *)head);

}

#endif /* _I40E_TXRX_H_ */