Changes in dev.c to support batching : add dev_add_skb_to_blist,
register_netdev recognizes batch aware drivers, and net_tx_action is
the sole user of batching.
Signed-off-by: Krishna Kumar <[EMAIL PROTECTED]>
---
dev.c | 77 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++---
1 files changed, 74 insertions(+), 3 deletions(-)
diff -ruNp org/net/core/dev.c new/net/core/dev.c
--- org/net/core/dev.c 2007-07-20 07:49:28.000000000 +0530
+++ new/net/core/dev.c 2007-07-20 08:31:35.000000000 +0530
@@ -1414,6 +1414,45 @@ static int dev_gso_segment(struct sk_buf
return 0;
}
+/*
+ * Add skb (skbs in case segmentation is required) to dev->skb_blist. We are
+ * holding QDISC RUNNING bit, so no one else can add to this list. Also, skbs
+ * are dequeued from this list when we call the driver, so the list is safe
+ * from simultaneous deletes too.
+ *
+ * Returns count of successful skb(s) added to skb_blist.
+ */
+int dev_add_skb_to_blist(struct sk_buff *skb, struct net_device *dev)
+{
+ if (!list_empty(&ptype_all))
+ dev_queue_xmit_nit(skb, dev);
+
+ if (netif_needs_gso(dev, skb)) {
+ if (unlikely(dev_gso_segment(skb))) {
+ kfree(skb);
+ return 0;
+ }
+
+ if (skb->next) {
+ int count = 0;
+
+ do {
+ struct sk_buff *nskb = skb->next;
+
+ skb->next = nskb->next;
+ __skb_queue_tail(dev->skb_blist, nskb);
+ count++;
+ } while (skb->next);
+
+ skb->destructor = DEV_GSO_CB(skb)->destructor;
+ kfree_skb(skb);
+ return count;
+ }
+ }
+ __skb_queue_tail(dev->skb_blist, skb);
+ return 1;
+}
+
int dev_hard_start_xmit(struct sk_buff *skb, struct net_device *dev)
{
if (likely(!skb->next)) {
@@ -1566,7 +1605,7 @@ gso:
/* reset queue_mapping to zero */
skb->queue_mapping = 0;
rc = q->enqueue(skb, q);
- qdisc_run(dev);
+ qdisc_run(dev, NULL);
spin_unlock(&dev->queue_lock);
rc = rc == NET_XMIT_BYPASS ? NET_XMIT_SUCCESS : rc;
@@ -1763,7 +1802,11 @@ static void net_tx_action(struct softirq
clear_bit(__LINK_STATE_SCHED, &dev->state);
if (spin_trylock(&dev->queue_lock)) {
- qdisc_run(dev);
+ /*
+ * Try to send out all skbs if batching is
+ * enabled.
+ */
+ qdisc_run(dev, dev->skb_blist);
spin_unlock(&dev->queue_lock);
} else {
netif_schedule(dev);
@@ -3397,6 +3440,28 @@ int register_netdevice(struct net_device
}
}
+ if (dev->features & NETIF_F_BATCH_SKBS) {
+ if (!dev->hard_start_xmit_batch ||
+ dev->tx_queue_len < MIN_QUEUE_LEN_BATCH) {
+ /*
+ * Batch TX requires API support in driver plus have
+ * a minimum sized queue.
+ */
+ printk(KERN_ERR "%s: Dropping NETIF_F_BATCH_SKBS "
+ "since no API support or queue len "
+ "is smaller than %d.\n",
+ dev->name, MIN_QUEUE_LEN_BATCH);
+ dev->features &= ~NETIF_F_BATCH_SKBS;
+ } else {
+ dev->skb_blist = kmalloc(sizeof *dev->skb_blist,
+ GFP_KERNEL);
+ if (dev->skb_blist) {
+ skb_queue_head_init(dev->skb_blist);
+ dev->tx_queue_len >>= 1;
+ }
+ }
+ }
+
/*
* nil rebuild_header routine,
* that should be never called and used as just bug trap.
@@ -3732,10 +3797,16 @@ void unregister_netdevice(struct net_dev
synchronize_net();
+ /* Deallocate batching structure */
+ if (dev->skb_blist) {
+ skb_queue_purge(dev->skb_blist);
+ kfree(dev->skb_blist);
+ dev->skb_blist = NULL;
+ }
+
/* Shutdown queueing discipline. */
dev_shutdown(dev);
-
/* Notify protocols, that we are about to destroy
this device. They should clean all the things.
*/
-
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