diff options
author | Tao Liu <xliutaox@google.com> | 2021-10-11 08:36:46 -0700 |
---|---|---|
committer | David S. Miller <davem@davemloft.net> | 2021-10-11 23:25:35 +0100 |
commit | 61d72c7e486b63340f1fadcf3bed4cae98f03d9b (patch) | |
tree | 77122eb48073115bd5d77b0bb2568bfe58382ed0 /drivers/net/ethernet/google/gve/gve_tx.c | |
parent | gve: Add rx buffer pagecnt bias (diff) | |
download | linux-dev-61d72c7e486b63340f1fadcf3bed4cae98f03d9b.tar.xz linux-dev-61d72c7e486b63340f1fadcf3bed4cae98f03d9b.zip |
gve: Do lazy cleanup in TX path
When TX queue is full, attemt to process enough TX completions
to avoid stalling the queue.
Fixes: f5cedc84a30d2 ("gve: Add transmit and receive support")
Signed-off-by: Tao Liu <xliutaox@google.com>
Signed-off-by: Catherine Sullivan <csully@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'drivers/net/ethernet/google/gve/gve_tx.c')
-rw-r--r-- | drivers/net/ethernet/google/gve/gve_tx.c | 94 |
1 files changed, 53 insertions, 41 deletions
diff --git a/drivers/net/ethernet/google/gve/gve_tx.c b/drivers/net/ethernet/google/gve/gve_tx.c index 9922ce46a635..a9cb241fedf4 100644 --- a/drivers/net/ethernet/google/gve/gve_tx.c +++ b/drivers/net/ethernet/google/gve/gve_tx.c @@ -144,7 +144,7 @@ static void gve_tx_free_ring(struct gve_priv *priv, int idx) gve_tx_remove_from_block(priv, idx); slots = tx->mask + 1; - gve_clean_tx_done(priv, tx, tx->req, false); + gve_clean_tx_done(priv, tx, priv->tx_desc_cnt, false); netdev_tx_reset_queue(tx->netdev_txq); dma_free_coherent(hdev, sizeof(*tx->q_resources), @@ -176,6 +176,7 @@ static int gve_tx_alloc_ring(struct gve_priv *priv, int idx) /* Make sure everything is zeroed to start */ memset(tx, 0, sizeof(*tx)); + spin_lock_init(&tx->clean_lock); tx->q_num = idx; tx->mask = slots - 1; @@ -328,10 +329,16 @@ static inline bool gve_can_tx(struct gve_tx_ring *tx, int bytes_required) return (gve_tx_avail(tx) >= MAX_TX_DESC_NEEDED && can_alloc); } +static_assert(NAPI_POLL_WEIGHT >= MAX_TX_DESC_NEEDED); + /* Stops the queue if the skb cannot be transmitted. */ -static int gve_maybe_stop_tx(struct gve_tx_ring *tx, struct sk_buff *skb) +static int gve_maybe_stop_tx(struct gve_priv *priv, struct gve_tx_ring *tx, + struct sk_buff *skb) { int bytes_required = 0; + u32 nic_done; + u32 to_do; + int ret; if (!tx->raw_addressing) bytes_required = gve_skb_fifo_bytes_required(tx, skb); @@ -339,29 +346,28 @@ static int gve_maybe_stop_tx(struct gve_tx_ring *tx, struct sk_buff *skb) if (likely(gve_can_tx(tx, bytes_required))) return 0; - /* No space, so stop the queue */ - tx->stop_queue++; - netif_tx_stop_queue(tx->netdev_txq); - smp_mb(); /* sync with restarting queue in gve_clean_tx_done() */ - - /* Now check for resources again, in case gve_clean_tx_done() freed - * resources after we checked and we stopped the queue after - * gve_clean_tx_done() checked. - * - * gve_maybe_stop_tx() gve_clean_tx_done() - * nsegs/can_alloc test failed - * gve_tx_free_fifo() - * if (tx queue stopped) - * netif_tx_queue_wake() - * netif_tx_stop_queue() - * Need to check again for space here! - */ - if (likely(!gve_can_tx(tx, bytes_required))) - return -EBUSY; + ret = -EBUSY; + spin_lock(&tx->clean_lock); + nic_done = gve_tx_load_event_counter(priv, tx); + to_do = nic_done - tx->done; - netif_tx_start_queue(tx->netdev_txq); - tx->wake_queue++; - return 0; + /* Only try to clean if there is hope for TX */ + if (to_do + gve_tx_avail(tx) >= MAX_TX_DESC_NEEDED) { + if (to_do > 0) { + to_do = min_t(u32, to_do, NAPI_POLL_WEIGHT); + gve_clean_tx_done(priv, tx, to_do, false); + } + if (likely(gve_can_tx(tx, bytes_required))) + ret = 0; + } + if (ret) { + /* No space, so stop the queue */ + tx->stop_queue++; + netif_tx_stop_queue(tx->netdev_txq); + } + spin_unlock(&tx->clean_lock); + + return ret; } static void gve_tx_fill_pkt_desc(union gve_tx_desc *pkt_desc, @@ -576,7 +582,7 @@ netdev_tx_t gve_tx(struct sk_buff *skb, struct net_device *dev) WARN(skb_get_queue_mapping(skb) >= priv->tx_cfg.num_queues, "skb queue index out of range"); tx = &priv->tx[skb_get_queue_mapping(skb)]; - if (unlikely(gve_maybe_stop_tx(tx, skb))) { + if (unlikely(gve_maybe_stop_tx(priv, tx, skb))) { /* We need to ring the txq doorbell -- we have stopped the Tx * queue for want of resources, but prior calls to gve_tx() * may have added descriptors without ringing the doorbell. @@ -672,19 +678,19 @@ static int gve_clean_tx_done(struct gve_priv *priv, struct gve_tx_ring *tx, return pkts; } -__be32 gve_tx_load_event_counter(struct gve_priv *priv, - struct gve_tx_ring *tx) +u32 gve_tx_load_event_counter(struct gve_priv *priv, + struct gve_tx_ring *tx) { - u32 counter_index = be32_to_cpu((tx->q_resources->counter_index)); + u32 counter_index = be32_to_cpu(tx->q_resources->counter_index); + __be32 counter = READ_ONCE(priv->counter_array[counter_index]); - return READ_ONCE(priv->counter_array[counter_index]); + return be32_to_cpu(counter); } bool gve_tx_poll(struct gve_notify_block *block, int budget) { struct gve_priv *priv = block->priv; struct gve_tx_ring *tx = block->tx; - bool repoll = false; u32 nic_done; u32 to_do; @@ -692,17 +698,23 @@ bool gve_tx_poll(struct gve_notify_block *block, int budget) if (budget == 0) budget = INT_MAX; + /* In TX path, it may try to clean completed pkts in order to xmit, + * to avoid cleaning conflict, use spin_lock(), it yields better + * concurrency between xmit/clean than netif's lock. + */ + spin_lock(&tx->clean_lock); /* Find out how much work there is to be done */ - tx->last_nic_done = gve_tx_load_event_counter(priv, tx); - nic_done = be32_to_cpu(tx->last_nic_done); - if (budget > 0) { - /* Do as much work as we have that the budget will - * allow - */ - to_do = min_t(u32, (nic_done - tx->done), budget); - gve_clean_tx_done(priv, tx, to_do, true); - } + nic_done = gve_tx_load_event_counter(priv, tx); + to_do = min_t(u32, (nic_done - tx->done), budget); + gve_clean_tx_done(priv, tx, to_do, true); + spin_unlock(&tx->clean_lock); /* If we still have work we want to repoll */ - repoll |= (nic_done != tx->done); - return repoll; + return nic_done != tx->done; +} + +bool gve_tx_clean_pending(struct gve_priv *priv, struct gve_tx_ring *tx) +{ + u32 nic_done = gve_tx_load_event_counter(priv, tx); + + return nic_done != tx->done; } |