From 6888fc87768eaa218b6244f2e78c55416706981a Mon Sep 17 00:00:00 2001 From: David Daney Date: Thu, 7 Jan 2010 11:05:03 -0800 Subject: Staging: Octeon Ethernet: Rewrite transmit code. Stop the queue if too many packets are queued. Restart it from a high resolution timer. Rearrange and simplify locking and SKB freeing code Signed-off-by: David Daney To: linux-mips@linux-mips.org To: gregkh@suse.de Patchwork: http://patchwork.linux-mips.org/patch/843/ Signed-off-by: Ralf Baechle --- drivers/staging/octeon/ethernet-tx.c | 172 +++++++++++++++++++++++------------ 1 file changed, 112 insertions(+), 60 deletions(-) (limited to 'drivers/staging/octeon/ethernet-tx.c') diff --git a/drivers/staging/octeon/ethernet-tx.c b/drivers/staging/octeon/ethernet-tx.c index e5695d9..05b58f8 100644 --- a/drivers/staging/octeon/ethernet-tx.c +++ b/drivers/staging/octeon/ethernet-tx.c @@ -64,6 +64,49 @@ #define GET_SKBUFF_QOS(skb) 0 #endif + +static inline int32_t cvm_oct_adjust_skb_to_free(int32_t skb_to_free, int fau) +{ + int32_t undo; + undo = skb_to_free > 0 ? MAX_SKB_TO_FREE : skb_to_free + MAX_SKB_TO_FREE; + if (undo > 0) + cvmx_fau_atomic_add32(fau, -undo); + skb_to_free = -skb_to_free > MAX_SKB_TO_FREE ? MAX_SKB_TO_FREE : -skb_to_free; + return skb_to_free; +} + +void cvm_oct_free_tx_skbs(struct octeon_ethernet *priv) +{ + int32_t skb_to_free; + int qos, queues_per_port; + queues_per_port = cvmx_pko_get_num_queues(priv->port); + /* Drain any pending packets in the free list */ + for (qos = 0; qos < queues_per_port; qos++) { + if (skb_queue_len(&priv->tx_free_list[qos]) == 0) + continue; + skb_to_free = cvmx_fau_fetch_and_add32(priv->fau+qos*4, MAX_SKB_TO_FREE); + skb_to_free = cvm_oct_adjust_skb_to_free(skb_to_free, priv->fau+qos*4); + + while (skb_to_free > 0) { + dev_kfree_skb_any(skb_dequeue(&priv->tx_free_list[qos])); + skb_to_free--; + } + } +} + +enum hrtimer_restart cvm_oct_restart_tx(struct hrtimer *timer) +{ + struct octeon_ethernet *priv = container_of(timer, struct octeon_ethernet, tx_restart_timer); + struct net_device *dev = cvm_oct_device[priv->port]; + + cvm_oct_free_tx_skbs(priv); + + if (netif_queue_stopped(dev)) + netif_wake_queue(dev); + + return HRTIMER_NORESTART; +} + /** * Packet transmit * @@ -77,13 +120,13 @@ int cvm_oct_xmit(struct sk_buff *skb, struct net_device *dev) union cvmx_buf_ptr hw_buffer; uint64_t old_scratch; uint64_t old_scratch2; - int dropped; int qos; - int queue_it_up; + enum {QUEUE_CORE, QUEUE_HW, QUEUE_DROP} queue_type; struct octeon_ethernet *priv = netdev_priv(dev); + struct sk_buff *to_free_list; int32_t skb_to_free; - int32_t undo; int32_t buffers_to_free; + unsigned long flags; #if REUSE_SKBUFFS_WITHOUT_FREE unsigned char *fpa_head; #endif @@ -94,9 +137,6 @@ int cvm_oct_xmit(struct sk_buff *skb, struct net_device *dev) */ prefetch(priv); - /* Start off assuming no drop */ - dropped = 0; - /* * The check on CVMX_PKO_QUEUES_PER_PORT_* is designed to * completely remove "qos" in the event neither interface @@ -268,9 +308,9 @@ int cvm_oct_xmit(struct sk_buff *skb, struct net_device *dev) skb->tc_verd = 0; #endif /* CONFIG_NET_CLS_ACT */ #endif /* CONFIG_NET_SCHED */ +#endif /* REUSE_SKBUFFS_WITHOUT_FREE */ dont_put_skbuff_in_hw: -#endif /* REUSE_SKBUFFS_WITHOUT_FREE */ /* Check if we can use the hardware checksumming */ if (USE_HW_TCPUDP_CHECKSUM && (skb->protocol == htons(ETH_P_IP)) && @@ -295,18 +335,7 @@ dont_put_skbuff_in_hw: cvmx_fau_fetch_and_add32(FAU_NUM_PACKET_BUFFERS_TO_FREE, 0); } - /* - * We try to claim MAX_SKB_TO_FREE buffers. If there were not - * that many available, we have to un-claim (undo) any that - * were in excess. If skb_to_free is positive we will free - * that many buffers. - */ - undo = skb_to_free > 0 ? - MAX_SKB_TO_FREE : skb_to_free + MAX_SKB_TO_FREE; - if (undo > 0) - cvmx_fau_atomic_add32(priv->fau+qos*4, -undo); - skb_to_free = -skb_to_free > MAX_SKB_TO_FREE ? - MAX_SKB_TO_FREE : -skb_to_free; + skb_to_free = cvm_oct_adjust_skb_to_free(skb_to_free, priv->fau+qos*4); /* * If we're sending faster than the receive can free them then @@ -317,60 +346,83 @@ dont_put_skbuff_in_hw: pko_command.s.reg0 = priv->fau + qos * 4; } - cvmx_pko_send_packet_prepare(priv->port, priv->queue + qos, - CVMX_PKO_LOCK_CMD_QUEUE); + if (pko_command.s.dontfree) + queue_type = QUEUE_CORE; + else + queue_type = QUEUE_HW; + + spin_lock_irqsave(&priv->tx_free_list[qos].lock, flags); /* Drop this packet if we have too many already queued to the HW */ - if (unlikely - (skb_queue_len(&priv->tx_free_list[qos]) >= MAX_OUT_QUEUE_DEPTH)) { - /* - DEBUGPRINT("%s: Tx dropped. Too many queued\n", dev->name); - */ - dropped = 1; + if (unlikely(skb_queue_len(&priv->tx_free_list[qos]) >= MAX_OUT_QUEUE_DEPTH)) { + if (dev->tx_queue_len != 0) { + /* Drop the lock when notifying the core. */ + spin_unlock_irqrestore(&priv->tx_free_list[qos].lock, flags); + netif_stop_queue(dev); + hrtimer_start(&priv->tx_restart_timer, + priv->tx_restart_interval, HRTIMER_MODE_REL); + spin_lock_irqsave(&priv->tx_free_list[qos].lock, flags); + + } else { + /* If not using normal queueing. */ + queue_type = QUEUE_DROP; + goto skip_xmit; + } } + + cvmx_pko_send_packet_prepare(priv->port, priv->queue + qos, + CVMX_PKO_LOCK_NONE); + /* Send the packet to the output queue */ - else if (unlikely - (cvmx_pko_send_packet_finish - (priv->port, priv->queue + qos, pko_command, hw_buffer, - CVMX_PKO_LOCK_CMD_QUEUE))) { + if (unlikely(cvmx_pko_send_packet_finish(priv->port, + priv->queue + qos, + pko_command, hw_buffer, + CVMX_PKO_LOCK_NONE))) { DEBUGPRINT("%s: Failed to send the packet\n", dev->name); - dropped = 1; + queue_type = QUEUE_DROP; } +skip_xmit: + to_free_list = NULL; - if (USE_ASYNC_IOBDMA) { - /* Restore the scratch area */ - cvmx_scratch_write64(CVMX_SCR_SCRATCH, old_scratch); - cvmx_scratch_write64(CVMX_SCR_SCRATCH + 8, old_scratch2); + switch (queue_type) { + case QUEUE_DROP: + skb->next = to_free_list; + to_free_list = skb; + priv->stats.tx_dropped++; + break; + case QUEUE_HW: + cvmx_fau_atomic_add32(FAU_NUM_PACKET_BUFFERS_TO_FREE, -1); + break; + case QUEUE_CORE: + __skb_queue_tail(&priv->tx_free_list[qos], skb); + break; + default: + BUG(); } - queue_it_up = 0; - if (unlikely(dropped)) { - dev_kfree_skb_any(skb); - priv->stats.tx_dropped++; - } else { - if (USE_SKBUFFS_IN_HW) { - /* Put this packet on the queue to be freed later */ - if (pko_command.s.dontfree) - queue_it_up = 1; - else - cvmx_fau_atomic_add32 - (FAU_NUM_PACKET_BUFFERS_TO_FREE, -1); - } else { - /* Put this packet on the queue to be freed later */ - queue_it_up = 1; - } + while (skb_to_free > 0) { + struct sk_buff *t = __skb_dequeue(&priv->tx_free_list[qos]); + t->next = to_free_list; + to_free_list = t; + skb_to_free--; } - if (queue_it_up) { - spin_lock(&priv->tx_free_list[qos].lock); - __skb_queue_tail(&priv->tx_free_list[qos], skb); - cvm_oct_free_tx_skbs(priv, skb_to_free, qos, 0); - spin_unlock(&priv->tx_free_list[qos].lock); - } else { - cvm_oct_free_tx_skbs(priv, skb_to_free, qos, 1); + spin_unlock_irqrestore(&priv->tx_free_list[qos].lock, flags); + + /* Do the actual freeing outside of the lock. */ + while (to_free_list) { + struct sk_buff *t = to_free_list; + to_free_list = to_free_list->next; + dev_kfree_skb_any(t); } - return 0; + if (USE_ASYNC_IOBDMA) { + /* Restore the scratch area */ + cvmx_scratch_write64(CVMX_SCR_SCRATCH, old_scratch); + cvmx_scratch_write64(CVMX_SCR_SCRATCH + 8, old_scratch2); + } + + return NETDEV_TX_OK; } /** -- cgit v1.1