Commit 447a851b authored by Jakub Kicinski's avatar Jakub Kicinski
Browse files

Merge branch 'sfc-TXQ-refactor' 



Edward Cree says:

====================
sfc: TXQ refactor

Refactor and unify partner-TXQ handling in the EF100 and legacy drivers.

The main thrust of this series is to remove from the legacy (Siena/EF10)
 driver the assumption that a netdev TX queue has precisely two hardware
 TXQs (checksummed and unchecksummed) associated with it, so that in
 future we can have more (e.g. for handling inner-header checksums) or
 fewer (e.g. to free up hardware queues for XDP usage).

Changes from v1:
 * better explain patch #1 in the commit message, and rename
   xmit_more_available to xmit_pending
 * add new patch #2 applying the same approach to ef100, for consistency
====================

Signed-off-by: default avatarJakub Kicinski <kuba@kernel.org>
parents 44a8c4f3 337792a2

drivers/net/ethernet/sfc/ef10.c

+1 −1
Original line number Diff line number Diff line
@@ -2367,7 +2367,7 @@ static void efx_ef10_tx_write(struct efx_tx_queue *tx_queue) 
	unsigned int write_ptr;

	efx_qword_t *txd;



	tx_queue->xmit_more_available = false;

	tx_queue->xmit_pending = false;

	if (unlikely(tx_queue->write_count == tx_queue->insert_count))

		return;

drivers/net/ethernet/sfc/ef100_tx.c

+19 −15
Original line number Diff line number Diff line
@@ -117,11 +117,13 @@ static efx_oword_t *ef100_tx_desc(struct efx_tx_queue *tx_queue, unsigned int in 
		return NULL;

}



void ef100_notify_tx_desc(struct efx_tx_queue *tx_queue)

static void ef100_notify_tx_desc(struct efx_tx_queue *tx_queue)

{

	unsigned int write_ptr;

	efx_dword_t reg;



	tx_queue->xmit_pending = false;



	if (unlikely(tx_queue->notify_count == tx_queue->write_count))

		return;
@@ -131,7 +133,6 @@ void ef100_notify_tx_desc(struct efx_tx_queue *tx_queue) 
	efx_writed_page(tx_queue->efx, &reg,

			ER_GZ_TX_RING_DOORBELL, tx_queue->queue);

	tx_queue->notify_count = tx_queue->write_count;

	tx_queue->xmit_more_available = false;

}



static void ef100_tx_push_buffers(struct efx_tx_queue *tx_queue)
@@ -359,28 +360,31 @@ int ef100_enqueue_skb(struct efx_tx_queue *tx_queue, struct sk_buff *skb) 
		goto err;

	ef100_tx_make_descriptors(tx_queue, skb, segments);



	fill_level = efx_channel_tx_fill_level(tx_queue->channel);

	fill_level = efx_channel_tx_old_fill_level(tx_queue->channel);

	if (fill_level > efx->txq_stop_thresh) {

		struct efx_tx_queue *txq2;



		netif_tx_stop_queue(tx_queue->core_txq);

		/* Re-read after a memory barrier in case we've raced with

		 * the completion path. Otherwise there's a danger we'll never

		 * restart the queue if all completions have just happened.

		 */

		smp_mb();

		fill_level = efx_channel_tx_fill_level(tx_queue->channel);

		efx_for_each_channel_tx_queue(txq2, tx_queue->channel)

			txq2->old_read_count = READ_ONCE(txq2->read_count);

		fill_level = efx_channel_tx_old_fill_level(tx_queue->channel);

		if (fill_level < efx->txq_stop_thresh)

			netif_tx_start_queue(tx_queue->core_txq);

	}



	if (__netdev_tx_sent_queue(tx_queue->core_txq, skb->len, xmit_more))

		tx_queue->xmit_more_available = false; /* push doorbell */

	else if (tx_queue->write_count - tx_queue->notify_count > 255)

		/* Ensure we never push more than 256 packets at once */

		tx_queue->xmit_more_available = false; /* push */

	else

		tx_queue->xmit_more_available = true; /* don't push yet */

	tx_queue->xmit_pending = true;



	if (!tx_queue->xmit_more_available)

	/* If xmit_more then we don't need to push the doorbell, unless there

	 * are 256 descriptors already queued in which case we have to push to

	 * ensure we never push more than 256 at once.

	 */

	if (__netdev_tx_sent_queue(tx_queue->core_txq, skb->len, xmit_more) ||

	    tx_queue->write_count - tx_queue->notify_count > 255)

		ef100_tx_push_buffers(tx_queue);



	if (segments) {
@@ -399,10 +403,10 @@ err: 


	/* If we're not expecting another transmit and we had something to push

	 * on this queue then we need to push here to get the previous packets

	 * out.  We only enter this branch from before the 'Update BQL' section

	 * above, so xmit_more_available still refers to the old state.

	 * out.  We only enter this branch from before the xmit_more handling

	 * above, so xmit_pending still refers to the old state.

	 */

	if (tx_queue->xmit_more_available && !xmit_more)

	if (tx_queue->xmit_pending && !xmit_more)

		ef100_tx_push_buffers(tx_queue);

	return rc;

}

drivers/net/ethernet/sfc/ef100_tx.h

+0 −1
Original line number Diff line number Diff line
@@ -17,7 +17,6 @@ 
int ef100_tx_probe(struct efx_tx_queue *tx_queue);

void ef100_tx_init(struct efx_tx_queue *tx_queue);

void ef100_tx_write(struct efx_tx_queue *tx_queue);

void ef100_notify_tx_desc(struct efx_tx_queue *tx_queue);

unsigned int ef100_tx_max_skb_descs(struct efx_nic *efx);



void ef100_ev_tx(struct efx_channel *channel, const efx_qword_t *p_event);

drivers/net/ethernet/sfc/farch.c

+1 −1
Original line number Diff line number Diff line
@@ -320,7 +320,7 @@ void efx_farch_tx_write(struct efx_tx_queue *tx_queue) 
	unsigned write_ptr;

	unsigned old_write_count = tx_queue->write_count;



	tx_queue->xmit_more_available = false;

	tx_queue->xmit_pending = false;

	if (unlikely(tx_queue->write_count == tx_queue->insert_count))

		return;

drivers/net/ethernet/sfc/net_driver.h

+16 −6
Original line number Diff line number Diff line
@@ -244,7 +244,7 @@ struct efx_tx_buffer { 
 * @tso_fallbacks: Number of times TSO fallback used

 * @pushes: Number of times the TX push feature has been used

 * @pio_packets: Number of times the TX PIO feature has been used

 * @xmit_more_available: Are any packets waiting to be pushed to the NIC

 * @xmit_pending: Are any packets waiting to be pushed to the NIC

 * @cb_packets: Number of times the TX copybreak feature has been used

 * @notify_count: Count of notified descriptors to the NIC

 * @empty_read_count: If the completion path has seen the queue as empty
@@ -292,7 +292,7 @@ struct efx_tx_queue { 
	unsigned int tso_fallbacks;

	unsigned int pushes;

	unsigned int pio_packets;

	bool xmit_more_available;

	bool xmit_pending;

	unsigned int cb_packets;

	unsigned int notify_count;

	/* Statistics to supplement MAC stats */
@@ -1681,10 +1681,6 @@ efx_channel_tx_fill_level(struct efx_channel *channel) 
	struct efx_tx_queue *tx_queue;

	unsigned int fill_level = 0;



	/* This function is currently only used by EF100, which maybe

	 * could do something simpler and just compute the fill level

	 * of the single TXQ that's really in use.

	 */

	efx_for_each_channel_tx_queue(tx_queue, channel)

		fill_level = max(fill_level,

				 tx_queue->insert_count - tx_queue->read_count);
@@ -1692,6 +1688,20 @@ efx_channel_tx_fill_level(struct efx_channel *channel) 
	return fill_level;

}



/* Conservative approximation of efx_channel_tx_fill_level using cached value */

static inline unsigned int

efx_channel_tx_old_fill_level(struct efx_channel *channel)

{

	struct efx_tx_queue *tx_queue;

	unsigned int fill_level = 0;



	efx_for_each_channel_tx_queue(tx_queue, channel)

		fill_level = max(fill_level,

				 tx_queue->insert_count - tx_queue->old_read_count);



	return fill_level;

}



/* Get all supported features.

 * If a feature is not fixed, it is present in hw_features.

 * If a feature is fixed, it does not present in hw_features, but

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