Subject: Re: iwlagn: order 2 page allocation failures
From: Pekka Enberg <penberg@cs.helsinki.fi>
To: Mel Gorman <mel@csn.ul.ie>
Cc: Frans Pop <elendil@planet.nl>,
	Larry Finger <Larry.Finger@lwfinger.net>,
	"John W. Linville" <linville@tuxdriver.com>,
	linux-kernel@vger.kernel.org, linux-wireless@vger.kernel.org,
	ipw3945-devel@lists.sourceforge.net,
	Andrew Morton <akpm@linux-foundation.org>,
	cl@linux-foundation.org, Assaf Krauss <assaf.krauss@intel.com>,
	Johannes Berg <johannes@sipsolutions.net>,
	Mohamed Abbas <mohamed.abbas@intel.com>
In-Reply-To: <20090909165545.GK24614@csn.ul.ie>
References: <200909060941.01810.elendil@planet.nl>
	 <4AA67139.80301@lwfinger.net> <20090909150418.GI24614@csn.ul.ie>
	 <200909091759.33655.elendil@planet.nl>  <20090909165545.GK24614@csn.ul.ie>
Date: Thu, 10 Sep 2009 11:18:42 +0300
Message-Id: <1252570722.4876.23.camel@penberg-laptop>
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Sender: linux-wireless-owner@vger.kernel.org

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