pasemi_mac: Batch up TX buffer frees

Postpone pci unmap and skb free of the transmitted buffers to outside of
the tx ring lock, batching them up 32 at a time.

Also increase the count threshold to 128.

Signed-off-by: Olof Johansson <olof@lixom.net>
Signed-off-by: Jeff Garzik <jeff@garzik.org>

1 files changed, 29 insertions, 10 deletions

diff --git a/drivers/net/pasemi_mac.c b/drivers/net/pasemi_mac.c
index f71a6864cdc2..4836d405cd5d 100644
--- a/drivers/net/pasemi_mac.c
+++ b/drivers/net/pasemi_mac.c
@@ -551,37 +551,56 @@ static int pasemi_mac_clean_tx(struct pasemi_mac *mac)
         int i;
         struct pasemi_mac_buffer *info;
         struct pas_dma_xct_descr *dp;
-        int start, count;
+        unsigned int start, count, limit;
+        unsigned int total_count;
         int flags;
+        struct sk_buff *skbs[32];
+        dma_addr_t dmas[32];
 
+        total_count = 0;
+restart:
         spin_lock_irqsave(&mac->tx->lock, flags);
 
         start = mac->tx->next_to_clean;
+        limit = min(mac->tx->next_to_use, start+32);
+
         count = 0;
 
-        for (i = start; i < mac->tx->next_to_use; i++) {
+        for (i = start; i < limit; i++) {
                 dp = &TX_DESC(mac, i);
+
                 if (unlikely(dp->mactx & XCT_MACTX_O))
+                        /* Not yet transmitted */
                         break;
 
-                count++;
-
                 info = &TX_DESC_INFO(mac, i);
-
-                pci_unmap_single(mac->dma_pdev, info->dma,
-                                 info->skb->len, PCI_DMA_TODEVICE);
-                dev_kfree_skb_irq(info->skb);
+                skbs[count] = info->skb;
+                dmas[count] = info->dma;
 
                 info->skb = NULL;
                 info->dma = 0;
                 dp->mactx = 0;
                 dp->ptr = 0;
+
+                count++;
         }
         mac->tx->next_to_clean += count;
         spin_unlock_irqrestore(&mac->tx->lock, flags);
         netif_wake_queue(mac->netdev);
 
-        return count;
+        for (i = 0; i < count; i++) {
+                pci_unmap_single(mac->dma_pdev, dmas[i],
+                                 skbs[i]->len, PCI_DMA_TODEVICE);
+                dev_kfree_skb_irq(skbs[i]);
+        }
+
+        total_count += count;
+
+        /* If the batch was full, try to clean more */
+        if (count == 32)
+                goto restart;
+
+        return total_count;
 }
 
 
@@ -777,7 +796,7 @@ static int pasemi_mac_open(struct net_device *dev)
                            PAS_IOB_DMA_RXCH_CFG_CNTTH(0));
 
         write_iob_reg(mac, PAS_IOB_DMA_TXCH_CFG(mac->dma_txch),
-                           PAS_IOB_DMA_TXCH_CFG_CNTTH(32));
+                           PAS_IOB_DMA_TXCH_CFG_CNTTH(128));
 
         /* Clear out any residual packet count state from firmware */
         pasemi_mac_restart_rx_intr(mac);