Re: problems with e1000 and jumboframes

From: Krzysztof Oledzki
Date: Thu Aug 03 2006 - 10:47:06 EST

On Thu, 3 Aug 2006, Benjamin LaHaise wrote:

On Thu, Aug 03, 2006 at 03:48:39PM +0200, Arnd Hannemann wrote:
However the box is a VIA Epia MII12000 with 1 GB of Ram and 1 GB of swap
enabled, so there should be plenty of memory available. HIGHMEM support
is off. The e1000 nic seems to be an 82540EM, which to my knowledge
should support jumboframes.

However I can't always reproduce this on a freshly booted system, so
someone else may be the culprit and leaking pages?

Any ideas how to debug this?

This is memory fragmentation, and all you can do is work around it until
the e1000 driver is changed to split jumbo frames up on rx. Here are a
few ideas that should improve things for you:

- switch to a 2GB/2GB split to recover the memory lost to highmem
(see Processor Type and Features / Memory split)
With 1 GB of RAM full 1GB/3GB (CONFIG_VMSPLIT_3G_OPT) seems to be enough...

- increase /proc/sys/vm/min_free_kbytes -- more free memory will
improve the odds that enough unfragmented memory is available for
incoming network packets

True. IMO, 65535 is a good starting point.

Best regards,
Krzysztof Olędzki