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ixgbe: move tx processing into NAPI context
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This patch moves the tx cleanup processing out of the MSI-X interrupt
processing and gives it it's own napi routine.  This allows the driver to
process TX cleanup in a polling context instead of in an interrupt context
which prevents TX from starving RX.

Signed-off-by: Alexander Duyck <alexander.h.duyck@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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Alexander Duyck authored and David S. Miller committed Jun 7, 2009
1 parent fe49f04 commit 91281fd
Showing 1 changed file with 107 additions and 34 deletions.
141 changes: 107 additions & 34 deletions drivers/net/ixgbe/ixgbe_main.c
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Original file line number Diff line number Diff line change
Expand Up @@ -1178,17 +1178,16 @@ static irqreturn_t ixgbe_msix_clean_tx(int irq, void *data)
r_idx = find_first_bit(q_vector->txr_idx, adapter->num_tx_queues);
for (i = 0; i < q_vector->txr_count; i++) {
tx_ring = &(adapter->tx_ring[r_idx]);
#ifdef CONFIG_IXGBE_DCA
if (adapter->flags & IXGBE_FLAG_DCA_ENABLED)
ixgbe_update_tx_dca(adapter, tx_ring);
#endif
tx_ring->total_bytes = 0;
tx_ring->total_packets = 0;
ixgbe_clean_tx_irq(q_vector, tx_ring);
r_idx = find_next_bit(q_vector->txr_idx, adapter->num_tx_queues,
r_idx + 1);
}

/* disable interrupts on this vector only */
ixgbe_irq_disable_queues(adapter, ((u64)1 << q_vector->v_idx));
napi_schedule(&q_vector->napi);

return IRQ_HANDLED;
}

Expand Down Expand Up @@ -1228,8 +1227,36 @@ static irqreturn_t ixgbe_msix_clean_rx(int irq, void *data)

static irqreturn_t ixgbe_msix_clean_many(int irq, void *data)
{
ixgbe_msix_clean_rx(irq, data);
ixgbe_msix_clean_tx(irq, data);
struct ixgbe_q_vector *q_vector = data;
struct ixgbe_adapter *adapter = q_vector->adapter;
struct ixgbe_ring *ring;
int r_idx;
int i;

if (!q_vector->txr_count && !q_vector->rxr_count)
return IRQ_HANDLED;

r_idx = find_first_bit(q_vector->txr_idx, adapter->num_tx_queues);
for (i = 0; i < q_vector->txr_count; i++) {
ring = &(adapter->tx_ring[r_idx]);
ring->total_bytes = 0;
ring->total_packets = 0;
r_idx = find_next_bit(q_vector->txr_idx, adapter->num_tx_queues,
r_idx + 1);
}

r_idx = find_first_bit(q_vector->rxr_idx, adapter->num_rx_queues);
for (i = 0; i < q_vector->rxr_count; i++) {
ring = &(adapter->rx_ring[r_idx]);
ring->total_bytes = 0;
ring->total_packets = 0;
r_idx = find_next_bit(q_vector->rxr_idx, adapter->num_rx_queues,
r_idx + 1);
}

/* disable interrupts on this vector only */
ixgbe_irq_disable_queues(adapter, ((u64)1 << q_vector->v_idx));
napi_schedule(&q_vector->napi);

return IRQ_HANDLED;
}
Expand Down Expand Up @@ -1274,40 +1301,53 @@ static int ixgbe_clean_rxonly(struct napi_struct *napi, int budget)
}

/**
* ixgbe_clean_rxonly_many - msix (aka one shot) rx clean routine
* ixgbe_clean_rxtx_many - msix (aka one shot) rx clean routine
* @napi: napi struct with our devices info in it
* @budget: amount of work driver is allowed to do this pass, in packets
*
* This function will clean more than one rx queue associated with a
* q_vector.
**/
static int ixgbe_clean_rxonly_many(struct napi_struct *napi, int budget)
static int ixgbe_clean_rxtx_many(struct napi_struct *napi, int budget)
{
struct ixgbe_q_vector *q_vector =
container_of(napi, struct ixgbe_q_vector, napi);
struct ixgbe_adapter *adapter = q_vector->adapter;
struct ixgbe_ring *rx_ring = NULL;
struct ixgbe_ring *ring = NULL;
int work_done = 0, i;
long r_idx;
bool tx_clean_complete = true;

r_idx = find_first_bit(q_vector->txr_idx, adapter->num_tx_queues);
for (i = 0; i < q_vector->txr_count; i++) {
ring = &(adapter->tx_ring[r_idx]);
#ifdef CONFIG_IXGBE_DCA
if (adapter->flags & IXGBE_FLAG_DCA_ENABLED)
ixgbe_update_tx_dca(adapter, ring);
#endif
tx_clean_complete &= ixgbe_clean_tx_irq(q_vector, ring);
r_idx = find_next_bit(q_vector->txr_idx, adapter->num_tx_queues,
r_idx + 1);
}

/* attempt to distribute budget to each queue fairly, but don't allow
* the budget to go below 1 because we'll exit polling */
budget /= (q_vector->rxr_count ?: 1);
budget = max(budget, 1);
r_idx = find_first_bit(q_vector->rxr_idx, adapter->num_rx_queues);
for (i = 0; i < q_vector->rxr_count; i++) {
rx_ring = &(adapter->rx_ring[r_idx]);
ring = &(adapter->rx_ring[r_idx]);
#ifdef CONFIG_IXGBE_DCA
if (adapter->flags & IXGBE_FLAG_DCA_ENABLED)
ixgbe_update_rx_dca(adapter, rx_ring);
ixgbe_update_rx_dca(adapter, ring);
#endif
ixgbe_clean_rx_irq(q_vector, rx_ring, &work_done, budget);
ixgbe_clean_rx_irq(q_vector, ring, &work_done, budget);
r_idx = find_next_bit(q_vector->rxr_idx, adapter->num_rx_queues,
r_idx + 1);
}

r_idx = find_first_bit(q_vector->rxr_idx, adapter->num_rx_queues);
rx_ring = &(adapter->rx_ring[r_idx]);
ring = &(adapter->rx_ring[r_idx]);
/* If all Rx work done, exit the polling mode */
if (work_done < budget) {
napi_complete(napi);
Expand All @@ -1321,6 +1361,46 @@ static int ixgbe_clean_rxonly_many(struct napi_struct *napi, int budget)

return work_done;
}

/**
* ixgbe_clean_txonly - msix (aka one shot) tx clean routine
* @napi: napi struct with our devices info in it
* @budget: amount of work driver is allowed to do this pass, in packets
*
* This function is optimized for cleaning one queue only on a single
* q_vector!!!
**/
static int ixgbe_clean_txonly(struct napi_struct *napi, int budget)
{
struct ixgbe_q_vector *q_vector =
container_of(napi, struct ixgbe_q_vector, napi);
struct ixgbe_adapter *adapter = q_vector->adapter;
struct ixgbe_ring *tx_ring = NULL;
int work_done = 0;
long r_idx;

r_idx = find_first_bit(q_vector->txr_idx, adapter->num_tx_queues);
tx_ring = &(adapter->tx_ring[r_idx]);
#ifdef CONFIG_IXGBE_DCA
if (adapter->flags & IXGBE_FLAG_DCA_ENABLED)
ixgbe_update_tx_dca(adapter, tx_ring);
#endif

if (!ixgbe_clean_tx_irq(q_vector, tx_ring))
work_done = budget;

/* If all Rx work done, exit the polling mode */
if (work_done < budget) {
napi_complete(napi);
if (adapter->itr_setting & 1)
ixgbe_set_itr_msix(q_vector);
if (!test_bit(__IXGBE_DOWN, &adapter->state))
ixgbe_irq_enable_queues(adapter, ((u64)1 << q_vector->v_idx));
}

return work_done;
}

static inline void map_vector_to_rxq(struct ixgbe_adapter *a, int v_idx,
int r_idx)
{
Expand Down Expand Up @@ -2213,12 +2293,15 @@ static void ixgbe_napi_enable_all(struct ixgbe_adapter *adapter)
for (q_idx = 0; q_idx < q_vectors; q_idx++) {
struct napi_struct *napi;
q_vector = adapter->q_vector[q_idx];
if (!q_vector->rxr_count)
continue;
napi = &q_vector->napi;
if ((adapter->flags & IXGBE_FLAG_MSIX_ENABLED) &&
(q_vector->rxr_count > 1))
napi->poll = &ixgbe_clean_rxonly_many;
if (adapter->flags & IXGBE_FLAG_MSIX_ENABLED) {
if (!q_vector->rxr_count || !q_vector->txr_count) {
if (q_vector->txr_count == 1)
napi->poll = &ixgbe_clean_txonly;
else if (q_vector->rxr_count == 1)
napi->poll = &ixgbe_clean_rxonly;
}
}

napi_enable(napi);
}
Expand All @@ -2236,8 +2319,6 @@ static void ixgbe_napi_disable_all(struct ixgbe_adapter *adapter)

for (q_idx = 0; q_idx < q_vectors; q_idx++) {
q_vector = adapter->q_vector[q_idx];
if (!q_vector->rxr_count)
continue;
napi_disable(&q_vector->napi);
}
}
Expand Down Expand Up @@ -3321,7 +3402,7 @@ static int ixgbe_alloc_q_vectors(struct ixgbe_adapter *adapter)
if (adapter->flags & IXGBE_FLAG_MSIX_ENABLED) {
num_q_vectors = adapter->num_msix_vectors - NON_Q_VECTORS;
napi_vectors = adapter->num_rx_queues;
poll = &ixgbe_clean_rxonly;
poll = &ixgbe_clean_rxtx_many;
} else {
num_q_vectors = 1;
napi_vectors = 1;
Expand All @@ -3335,9 +3416,7 @@ static int ixgbe_alloc_q_vectors(struct ixgbe_adapter *adapter)
q_vector->adapter = adapter;
q_vector->eitr = adapter->eitr_param;
q_vector->v_idx = q_idx;
if (q_idx < napi_vectors)
netif_napi_add(adapter->netdev, &q_vector->napi,
(*poll), 64);
netif_napi_add(adapter->netdev, &q_vector->napi, (*poll), 64);
adapter->q_vector[q_idx] = q_vector;
}

Expand Down Expand Up @@ -3365,22 +3444,16 @@ static int ixgbe_alloc_q_vectors(struct ixgbe_adapter *adapter)
static void ixgbe_free_q_vectors(struct ixgbe_adapter *adapter)
{
int q_idx, num_q_vectors;
int napi_vectors;

if (adapter->flags & IXGBE_FLAG_MSIX_ENABLED) {
if (adapter->flags & IXGBE_FLAG_MSIX_ENABLED)
num_q_vectors = adapter->num_msix_vectors - NON_Q_VECTORS;
napi_vectors = adapter->num_rx_queues;
} else {
else
num_q_vectors = 1;
napi_vectors = 1;
}

for (q_idx = 0; q_idx < num_q_vectors; q_idx++) {
struct ixgbe_q_vector *q_vector = adapter->q_vector[q_idx];

adapter->q_vector[q_idx] = NULL;
if (q_idx < napi_vectors)
netif_napi_del(&q_vector->napi);
netif_napi_del(&q_vector->napi);
kfree(q_vector);
}
}
Expand Down

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