Re: [Xen-devel] network dropouts

[Jan Kundrát <jan.kundrat@xxxxxx>]

Keir Fraser wrote:
> > no, I'm setting it manually via `ifconfig` in init script. Notice the 
> > following lines in kernel log:
> > Dec 12 20:33:23 zirafa xen-br0: port 1(eth0) entering disabled state
> > Dec 12 20:34:23 zirafa xen-br0: port 1(eth0) entering learning state
> >
> > Why is eth0 (the only physical device in xen-br0) getting into disabled 
> > state?
>
> My guess would be that the bridge code is receiving carrier-change
> events from eth0. This causes it to put eth0 in disabled state for a
> while. 
>
> One way to check this would be to add some printk()'s to
> net/bridge/br_notify.c and see whether you are getting NETDEV_CHANGE
> or NETDEV_DOWN events. If so, it may be that your physical connection,
> or your router/switch/hub, is a bit dodgy.
>
> None of the other paths via which the interface may get disabled seem
> very likely to occur, but we can look at those if it doesn't appear
> that you are getting NETDEV events.
Hi, I finally managed to get it. Here is my patch to net/bridge/br_notify.c:

--- br_notify.c.original        2004-11-14 15:31:58.000000000 +0100
+++ br_notify.c 2004-12-17 13:57:19.000000000 +0100
@@ -45,37 +45,58 @@
        switch (event) {
        case NETDEV_CHANGEMTU:
                dev_set_mtu(br->dev, br_min_mtu(br));
+               printk("NETDEV_CHANGEMTU\n");
                break;

        case NETDEV_CHANGEADDR:
                br_fdb_changeaddr(p, dev->dev_addr);
                br_stp_recalculate_bridge_id(br);
+               printk("NETDEV_CHANGEADDR\n");
                break;

        case NETDEV_CHANGE:     /* device is up but carrier changed */
-               if (!(br->dev->flags & IFF_UP))
+               printk("NETDEV_CHANGE ");
+               if (!(br->dev->flags & IFF_UP)) {
+                       printk("- !(br->dev->flags & IFF_UP)==true\n");
                        break;
+               }

                if (netif_carrier_ok(dev)) {
-                       if (p->state == BR_STATE_DISABLED)
+                       printk("- netif_carrier_ok(dev)==true ");
+                       if (p->state == BR_STATE_DISABLED) {
+                               printk("- calling br_stp_enable_port(p)");
                                br_stp_enable_port(p);
+                       }
                } else {
-                       if (p->state != BR_STATE_DISABLED)
+                       printk("- netif_carrier_ok(dev)!=true ");
+                       if (p->state != BR_STATE_DISABLED) {
+                               printk(" - calling br_stp_disable_port(p)");
                                br_stp_disable_port(p);
+                       }
                }
+               printk("\n");
                break;

        case NETDEV_DOWN:
-               if (br->dev->flags & IFF_UP)
+               printk("NETDEV_DOWN ");
+               if (br->dev->flags & IFF_UP) {
+                       printk("- calling br_stp_disable_port(p)");
                        br_stp_disable_port(p);
+               }
+               printk("\n");
                break;

        case NETDEV_UP:
-               if (netif_carrier_ok(dev) && (br->dev->flags & IFF_UP))
+               printk("NETDEV_UP ");
+               if (netif_carrier_ok(dev) && (br->dev->flags & IFF_UP)) {
+                       printk("- calling br_stp_enable_port(p)");
                        br_stp_enable_port(p);
+               }
+               printk("\n");
                break;

        case NETDEV_UNREGISTER:
+               printk("NETDEV_UNREGISTER\n");
                spin_unlock_bh(&br->lock);
                br_del_if(br, dev);
                goto done;

and messages from syslog (obviously my patch is wrong as it'ss putting 
several messages together (missing "\n")):
Dec 17 18:37:02 zirafa NETDEV_CHANGE - netif_carrier_ok(dev)!=true  - 
calling br_stp_disable_port(p)<6>xen-br0: port 1(eth0) entering disabled 
state
Dec 17 18:37:02 zirafa
Dec 17 18:38:02 zirafa NETDEV_CHANGE - netif_carrier_ok(dev)==true - 
calling br_stp_enable_port(p)<6>xen-br0: port 1(eth0) entering learning 
state
Dec 17 18:38:02 zirafa
Dec 17 18:38:02 zirafa xen-br0: topology change detected, propagating
Dec 17 18:38:02 zirafa xen-br0: port 1(eth0) entering forwarding state

However, `ifconfig` says 0 for carrier:

eth0      Link encap:Ethernet  HWaddr 00:10:4B:B6:BD:0E
          inet addr:10.18.6.60  Bcast:10.18.6.63  Mask:255.255.255.192
          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
          RX packets:3382 errors:0 dropped:0 overruns:0 frame:0
          TX packets:3164 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1000
          RX bytes:312112 (304.7 Kb)  TX bytes:334955 (327.1 Kb)
          Interrupt:11 Base address:0xe400
xen-br0   Link encap:Ethernet  HWaddr 00:10:4B:B6:BD:0E
          inet addr:10.18.6.60  Bcast:10.18.6.63  Mask:255.255.255.255
          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
          RX packets:3186 errors:0 dropped:0 overruns:0 frame:0
          TX packets:2971 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:0
          RX bytes:246738 (240.9 Kb)  TX bytes:307288 (300.0 Kb)

Xen box has 3c590 card which is connected by cat5 1m long patch cable 
into TP-Link TL-SL3210 managable switch (which has 8*100Mbps, 1*1Gbps 
and 1 GBIC slot) which was quite expensive, so I don't think it's such a 
piece of s*** :-), but I might be mistaken (hope I am not).
Possible workaround could be setting up routing between domain0 and 
other domains, but it won't be a simple task.
TIA,
jkt

--
cd /local/pub && more beer > /dev/mouth



-------------------------------------------------------
SF email is sponsored by - The IT Product Guide
Read honest & candid reviews on hundreds of IT Products from real users.
Discover which products truly live up to the hype. Start reading now. 
http://productguide.itmanagersjournal.com/
_______________________________________________
Xen-devel mailing list
Xen-devel@xxxxxxxxxxxxxxxxxxxxx
https://lists.sourceforge.net/lists/listinfo/xen-devel