Re: iwlagn: order 2 page allocation failures

[Pekka Enberg <penberg@cs.helsinki.fi>]

On Wed, 2009-09-09 at 17:55 +0100, Mel Gorman wrote:
> On Wed, Sep 09, 2009 at 05:59:30PM +0200, Frans Pop wrote:
> > On Wednesday 09 September 2009, Mel Gorman wrote:
> > > Franz, in the full dmesg was there any mention of "SLUB: Unable to
> > > allocate memory on node"?
> > 
> > No, nothing at all. I double checked the kernel log, but it was completely 
> > quiet in the hours before and after the messages I already posted.
> > 
> 
> Ok, that in itself is unexpected.
> 
> Pekka, it looks from the stack trace that the failure is from
> __alloc_skb and I am guessing the failure path is around here
> 
>         size = SKB_DATA_ALIGN(size);
>         data = kmalloc_node_track_caller(size + sizeof(struct skb_shared_info),
>                         gfp_mask, node);
>         if (!data)
>                 goto nodata;
> 
> Why would the SLUB out-of-memory message not appear? It's hardly
> tripping up on printk_ratelimit() is it?

That's because it's a large allocation that's passed directly to the
page allocator. See kmalloc_large_node(), for example.

			Pekka