Re: [Xen-devel] network hang trigger

[Bin Ren <br260@xxxxxxxxx>]

I've just modified the netfront.c (haven't touched netback.c yet). I've 
done two modifications: (1) free sk_buff properly on the transmit path (2) 
In netif_poll(...) function, packets **should not** be passed to 
netif_rx(); instead, use: int netif_receive_skb(struct sk_buff *skb).
With these two modifications, under 'ping -s 6000', network only 
occasionally loses a few packets but *very soon* recovers. It's much more 
stable than before. I'll take a closer look at netfront.c and netback.c 
tomorrow.
Here is the patch. Please try it out. With your results, the changes may 
get pushed into the repository.
-- Bin Ren

===== linux-2.6.8.1-xen-sparse/drivers/xen/netfront/netfront.c 1.49 vs 
edited ===== --- 
1.49/linux-2.6.8.1-xen-sparse/drivers/xen/netfront/netfront.c 2004-08-27 
13:28:33 +01:00 +++ 
edited/linux-2.6.8.1-xen-sparse/drivers/xen/netfront/netfront.c 2004-09-16 
00:34:33 +01:00 @@ -329,7 +329,7 @@
    {
        printk(KERN_ALERT "%s: full queue wasn't stopped!\n", dev->name);
        netif_stop_queue(dev);
-        return -ENOBUFS;
+       goto drop;
    }

    if ( unlikely((((unsigned long)skb->data & ~PAGE_MASK) + skb->len) >=
@@ -337,7 +337,7 @@
    {
        struct sk_buff *new_skb;
        if ( unlikely((new_skb = alloc_skb_page()) == NULL) )
-            return 1;
+            goto drop;
        skb_put(new_skb, skb->len);
        memcpy(new_skb->data, skb->data, skb->len);
        dev_kfree_skb(skb);
@@ -349,7 +349,7 @@
    if ( np->backend_state != BEST_CONNECTED )
    {
        spin_unlock_irq(&np->tx_lock);
-        return 1;
+        goto drop;
    }

    i = np->tx->req_prod;
@@ -385,6 +385,10 @@
        notify_via_evtchn(np->evtchn);

    return 0;
+
+ drop:
+    dev_kfree_skb(skb);
+    return 0;
}


@@ -501,7 +505,7 @@
        skb->protocol = eth_type_trans(skb, dev);

        /* Pass it up. */
-        netif_rx(skb);
+        netif_receive_skb(skb);
        dev->last_rx = jiffies;
    }


-------------------------------------------------------
This SF.Net email is sponsored by: thawte's Crypto Challenge Vl
Crack the code and win a Sony DCRHC40 MiniDV Digital Handycam
Camcorder. More prizes in the weekly Lunch Hour Challenge.
Sign up NOW http://ad.doubleclick.net/clk;10740251;10262165;m
_______________________________________________
Xen-devel mailing list
Xen-devel@xxxxxxxxxxxxxxxxxxxxx
https://lists.sourceforge.net/lists/listinfo/xen-devel