[FWD] [Xen-users] Jumbo frame support for Xen

[FWD] [Xen-users] Jumbo frame support for Xen

[PÁSZTOR György]

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Hi,

I just got some hint, to forward my original mail to this list too.

Cheers,
----- Forwarded message from PÁSZTOR György <pasztor@linux.gyakg.u-szeged.hu> -----

Hi,

I had to use bridge interfaces with mtu other than 9000, so I started to
google for a solution. Then I found this thread:
http://web.archiveorange.com/archive/v/ZvO4j2ymSAvyo8GNrwhY

But, It didn't work, as the original author says.
I tried to find an easier way, to setup this, so as I found out: If you
configure a vif's mtu, the logical solution is to use the same mtu as the
bridge interface -> So I wrote a smaller, nicer, and... a working patch.

The "trick" is that, I don't use the xen's bridge creation scripts, I
preconfigure my bridge interfaces from my Debian configuration, far before
the xen things would start.
bridge entry from my /etc/network/interfaces:
auto br201
iface br201 inet static
	address 10.0.3.5
	netmask 255.255.0.0
	network 10.0.0.0
	broadcast 10.0.255.255
	mtu 9000
	bridge_ports bond0.201
	bridge_fd 0
	bridge_maxwait 0

This iface config pre-creates the vlan if on my bonding if, creates the
bridge, add the bond.vlan into my bridge interface, and every mtu is OK,
until xen starts...
Then, with my patched xen scripts,... work again, still, whatever you want:
It's just work! ;-)

Use it wise, and for your own risk!

The patch:

diff -urN /etc/xen/scripts.orig/vif-bridge /etc/xen/scripts/vif-bridge
--- /etc/xen/scripts.orig/vif-bridge	2011-04-14 15:24:51.000000000 +0200
+++ /etc/xen/scripts/vif-bridge	2011-10-12 18:13:13.873102049 +0200
@@ -82,6 +82,7 @@
 case "$command" in
     online)
 	setup_bridge_port "$vif"
+	set_vif_mtu "$vif" "$(get_if_mtu $bridge)"
 	add_to_bridge "$bridge" "$vif"
         ;;
 
diff -urN /etc/xen/scripts.orig/xen-network-common.sh /etc/xen/scripts/xen-network-common.sh
--- /etc/xen/scripts.orig/xen-network-common.sh	2010-06-21 15:46:02.000000000 +0200
+++ /etc/xen/scripts/xen-network-common.sh	2011-10-12 18:07:00.456909410 +0200
@@ -116,3 +116,19 @@
     ip link set ${dev} up
 }
 
+get_if_mtu () {
+    local dev=$1
+    local line
+    ip link show $dev | \
+	( read line
+	line="${line##*mtu }"
+	line="${line%% *}"
+	echo $line
+	cat >/dev/null )
+}
+
+set_vif_mtu () {
+    local vif=$1
+    local mtu=$2
+    ip link set "$vif" mtu "$mtu"
+}

Cheers!


_______________________________________________
Xen-users mailing list
Xen-users@lists.xensource.com
http://lists.xensource.com/xen-users

----- End forwarded message -----

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Re: [FWD] [Xen-users] Jumbo frame support for Xen

[Konrad Rzeszutek Wilk]

On Thu, Oct 13, 2011 at 12:00:58PM +0200, PÁSZTOR György wrote:
> Hi,
> 
> I just got some hint, to forward my original mail to this list too.

The patch looks OK, except that it does not check for the cases where the
mtu is not set.

Would you be up for respinning the patch with that check and also include
your Signed-off-by?

> 
> Cheers,
> ----- Forwarded message from PÁSZTOR György <pasztor@linux.gyakg.u-szeged.hu> -----
> 
> Hi,
> 
> I had to use bridge interfaces with mtu other than 9000, so I started to
> google for a solution. Then I found this thread:
> http://web.archiveorange.com/archive/v/ZvO4j2ymSAvyo8GNrwhY
> 
> But, It didn't work, as the original author says.
> I tried to find an easier way, to setup this, so as I found out: If you
> configure a vif's mtu, the logical solution is to use the same mtu as the
> bridge interface -> So I wrote a smaller, nicer, and... a working patch.
> 
> The "trick" is that, I don't use the xen's bridge creation scripts, I
> preconfigure my bridge interfaces from my Debian configuration, far before
> the xen things would start.
> bridge entry from my /etc/network/interfaces:
> auto br201
> iface br201 inet static
> 	address 10.0.3.5
> 	netmask 255.255.0.0
> 	network 10.0.0.0
> 	broadcast 10.0.255.255
> 	mtu 9000
> 	bridge_ports bond0.201
> 	bridge_fd 0
> 	bridge_maxwait 0
> 
> This iface config pre-creates the vlan if on my bonding if, creates the
> bridge, add the bond.vlan into my bridge interface, and every mtu is OK,
> until xen starts...
> Then, with my patched xen scripts,... work again, still, whatever you want:
> It's just work! ;-)
> 
> Use it wise, and for your own risk!
> 
> The patch:
> 
> diff -urN /etc/xen/scripts.orig/vif-bridge /etc/xen/scripts/vif-bridge
> --- /etc/xen/scripts.orig/vif-bridge	2011-04-14 15:24:51.000000000 +0200
> +++ /etc/xen/scripts/vif-bridge	2011-10-12 18:13:13.873102049 +0200
> @@ -82,6 +82,7 @@
>  case "$command" in
>      online)
>  	setup_bridge_port "$vif"
> +	set_vif_mtu "$vif" "$(get_if_mtu $bridge)"
>  	add_to_bridge "$bridge" "$vif"
>          ;;
>  
> diff -urN /etc/xen/scripts.orig/xen-network-common.sh /etc/xen/scripts/xen-network-common.sh
> --- /etc/xen/scripts.orig/xen-network-common.sh	2010-06-21 15:46:02.000000000 +0200
> +++ /etc/xen/scripts/xen-network-common.sh	2011-10-12 18:07:00.456909410 +0200
> @@ -116,3 +116,19 @@
>      ip link set ${dev} up
>  }
>  
> +get_if_mtu () {
> +    local dev=$1
> +    local line
> +    ip link show $dev | \
> +	( read line
> +	line="${line##*mtu }"
> +	line="${line%% *}"
> +	echo $line
> +	cat >/dev/null )
> +}
> +
> +set_vif_mtu () {
> +    local vif=$1
> +    local mtu=$2
> +    ip link set "$vif" mtu "$mtu"
> +}
> 
> Cheers!
> 
> 
> _______________________________________________
> Xen-users mailing list
> Xen-users@lists.xensource.com
> http://lists.xensource.com/xen-users
> 
> ----- End forwarded message -----


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