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i40e: Add a SW workaround for lost interrupts

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This patch adds a workaround for cases where we might have
interrupts that got lost but WB happened.
If that happens without this patch we will see a tx_timeout.
To work around it, this patch goes ahead and reschedules NAPI
in that situation, if NAPI is not already scheduled.
We also add a counter in ethtool to keep track of when
we detect a case of tx_lost_interrupt.

Note: napi_reschedule() can be safely called from process/service_task
context and is done in other drivers as well without an issue.

Change-ID: I00f98f1ce3774524d9421227652bef20fcbd0d20
Signed-off-by: Anjali Singhai Jain <anjali.singhai@intel.com>
Tested-by: Andrew Bowers <andrewx.bowers@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
This commit is contained in:
Anjali Singhai Jain
2016-01-15 14:33:12 -08:00
committed by Jeff Kirsher
parent f734dfff2f
commit dd353109e4
7 changed files with 40 additions and 20 deletions
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10
drivers/net/ethernet/intel/i40evf/i40e_txrx.c
View File

@@ -129,15 +129,19 @@ void i40evf_free_tx_resources(struct i40e_ring *tx_ring)
/**
* i40evf_get_tx_pending - how many Tx descriptors not processed
* @tx_ring: the ring of descriptors
* @in_sw: is tx_pending being checked in SW or HW
*
* Since there is no access to the ring head register
* in XL710, we need to use our local copies
**/
u32 i40evf_get_tx_pending(struct i40e_ring *ring)
u32 i40evf_get_tx_pending(struct i40e_ring *ring, bool in_sw)
{
u32 head, tail;
head = i40e_get_head(ring);
if (!in_sw)
head = i40e_get_head(ring);
else
head = ring->next_to_clean;
tail = readl(ring->tail);
if (head != tail)
@@ -259,7 +263,7 @@ static bool i40e_clean_tx_irq(struct i40e_ring *tx_ring, int budget)
* them to be written back in case we stay in NAPI.
* In this mode on X722 we do not enable Interrupt.
*/
j = i40evf_get_tx_pending(tx_ring);
j = i40evf_get_tx_pending(tx_ring, false);
if (budget &&
((j / (WB_STRIDE + 1)) == 0) && (j > 0) &&

3
drivers/net/ethernet/intel/i40evf/i40e_txrx.h
View File

@@ -202,6 +202,7 @@ struct i40e_tx_queue_stats {
u64 tx_done_old;
u64 tx_linearize;
u64 tx_force_wb;
u64 tx_lost_interrupt;
};
struct i40e_rx_queue_stats {
@@ -326,7 +327,7 @@ 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);
void i40evf_force_wb(struct i40e_vsi *vsi, struct i40e_q_vector *q_vector);
u32 i40evf_get_tx_pending(struct i40e_ring *ring);
u32 i40evf_get_tx_pending(struct i40e_ring *ring, bool in_sw);
/**
* i40e_get_head - Retrieve head from head writeback