[ELDK] Jumbo Frames, sil24 SATA driver, and kswapd0 page allocation failures

Jonathan Haws Jonathan.Haws at sdl.usu.edu
Thu Aug 13 00:06:21 CEST 2009


> What is the size of your Jumbo Frame MTU? I have had problems on the
> 440EP with an MTU larger than 4080 related to the MAL allocating
> multiple buffer descriptors. Try shrinking your MTU to below 4K and
> see if the problem still occurs.

I have tried shrinking it to 4000 and I still saw the error.  Our
system needs to use a standard jumbo frame however (9014 byte MTU). 
Looking through the EMAC code, it appears that the driver writer took
the time to implement scatter/gather linking of the multiple
descriptors.

The thing that concerns me is that if it really was an MTU issue, it
would occur just by dumping data over the network.  I ran the system
overnight receiving 36 MBytes/s without a single hiccup.  That tells
me that the problem is not in the network, but somewhere in how the
ATA driver is handling memory.

I may be wrong though (and I am hoping that I am and someone knows the
answer).

Thanks,

Jonathan





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