Page allocation failure with MTU 9000

[Ben Hutchings <ben@decadent.org.uk>]

On Thu, Jun 27, 2013 at 09:11:05PM +0200, Damien Martins wrote:
> cat /etc/debian_version
> 7.1
> 
> uname -a
> Linux nassounet 3.2.0-4-orion5x #1 Debian 3.2.41-2 armv5tel GNU/Linux
> 
> When settings MTU to 9000 (ifconfig eth0 mtu 9000) :
> [4098918.032189] mv643xx_eth_port mv643xx_eth_port.0: eth0: link up,
> 1000 Mb/s, full duplex, flow control disabled
> 
> When having heavy network usage (300MB file transfer using NFS) :
> 
> [4101722.937455] swapper: page allocation failure: order:2, mode:0x20
[...]

This is a common failure case when using most of the system memory and
using stupid drivers or hardware that can't scatter received packets
across individual buffers.  I don't know whether the hardware in this
case is capable of scattering.

Increasing sysctl vm.min_free_kbytes is sometimes an effective
workaround, but it may be that your system just don't have enough
memory to make jumbo packets usable.

Ben.

-- 
Ben Hutchings
We get into the habit of living before acquiring the habit of thinking.
                                                              - Albert Camus